Title:
GOLF BALL COMPOSITIONS
Kind Code:
A1


Abstract:
A golf ball is disclosed which includes a central core; one or more mantle layers and an outer cover layer and where one or more of the core and one or more mantle layers is coated with a coating composition which includes one or more of the following components; a polysulfide silane; a waterborne polyurethane resin composition; a waterborne urethane modified acrylic resin composition; or an epoxy resin composition.



Inventors:
Kim, Hyun J. (Carlsbad, CA, US)
Jeon, Hong G. (Carlsbad, CA, US)
Bradford, Eric William (San Marcos, CA, US)
Application Number:
13/787519
Publication Date:
07/03/2014
Filing Date:
03/06/2013
Assignee:
Taylor Made Golf Company, Inc. (Carlsbad, CA, US)
Primary Class:
Other Classes:
427/407.1, 473/374
International Classes:
A63B37/00
View Patent Images:
Related US Applications:
20060211517Golf ballSeptember, 2006Isogawa et al.
20050176518Practice golf cage with a golf ball gathering central locationAugust, 2005Doherty et al.
20070281796MUSCLE-BACK IRON GOLF CLUBS WITH HIGHER MOMENT OF INTERTIA AND LOWER CENTER OF GRAVITYDecember, 2007Gilbert et al.
20110201453GOLF BALLAugust, 2011Kasashima et al.
20080171621Baseball and softball base anchoring systemJuly, 2008Jacobson
20150072812BROADHEADMarch, 2015Sanford
20110287867GOLF BALLNovember, 2011Higuchi et al.
20060035733Football hiking systemFebruary, 2006Silver et al.
20160096093Projectile and Throwing Apparatus and Game for Projectile ThrowingApril, 2016Evans
20170120119GOLFING ACCESSORY HAVING IMPROVED VISIBILITY AND FUNCTIONALITYMay, 2017Trojan
20100279785Angle Adjustment Features for Golf ClubsNovember, 2010Oldknow V et al.



Foreign References:
JPH02264674A1990-10-29
Primary Examiner:
STANCZAK, MATTHEW BRIAN
Attorney, Agent or Firm:
KLARQUIST SPARKMAN, LLP (PORTLAND, OR, US)
Claims:
What is claimed is:

1. A golf ball comprising; A) a central core; B) one or more mantle layers; and C) an outer cover layer wherein one or more of said core and said one or more mantle layers is coated with a coating composition selected from the group consisting of; a) a polysulfide silane; b) a waterborne polyurethane resin composition; c) a waterborne urethane modified acrylic resin composition; d) an epoxy resin composition; and e) any and all combinations of a-d.

2. The golf ball of claim 1 wherein one or more of said mantle layers comprises a polymer selected from the group consisting of natural rubbers, synthetic rubbers, thermoset polyurethanes, thermoset polyureas, thermoplastic polyurethanes, thermoplastic polyureas, metallocene catalyzed polymers, maleic anhydride grafted metallocene polymers, unimodal ethylene/carboxylic acid copolymers, unimodal ethylene/carboxylic acid/carboxylate terpolymers, bimodal ethylene/carboxylic acid copolymers, bimodal ethylene/carboxylic acid/carboxylate terpolymers, polyamides, copolyamides, polyesters, copolyesters, polycarbonates, polyolefins, halogenated polyolefins, halogenated polyalkylenes, polyalkenamer, polyphenylene oxides, polyphenylene sulfides, diallyl phthalate polymers, polyimides, polyvinyl chlorides, polyamide-ionomers, polyurethane-ionomers, polyvinyl alcohols, polyarylates, polyacrylates, polyphenylene ethers, impact-modified polyphenylene ethers, polystyrenes, high impact polystyrenes, acrylonitrile-butadiene-styrene copolymers, styrene-acrylonitriles (SAN), acrylonitrile-styrene-acrylonitriles, styrene-maleic anhydride (S/MA) polymers, styrenic block copolymers, functionalized styrenic block copolymers cellulosic polymers, liquid crystal polymers (LCP), ethylene-propylene-diene terpolymers (EPDM), ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymers, propylene elastomers, ethylene vinyl acetates, polysiloxanes, and any and all combinations thereof.

3. The golf ball of claim 1 wherein one or more of said mantle layers comprises greater than 85% by weight of a polyalkenamer rubber selected from the group consisting of polybutenamer rubber, polypentenamer rubber, polyhexenamer rubber, polyheptenamer rubber, polyoctenamer rubber, polynonenamer rubber, polydecenamer rubber polyundecenamer rubber, polydodecenamer rubber, polytridecenamer rubber and any and all combinations thereof.

4. The golf ball of claim 1 wherein one or more of said mantle layers comprises greater than 90% by weight of a polyalkenamer rubber selected from the group consisting of polypentenamer rubber, polyoctenamer rubber, polydodecenamer rubber and any and all combinations thereof.

5. The golf ball of claim 1 wherein the outer cover layer comprises a thermoplastic elastomer, a polyalkenamer composition, a thermoset polyurethane, a thermoplastic polyurethane, a thermoset polyurea, a thermoplastic polyurea, a polyamide, a unimodal ionomer, a bimodal ionomer, a modified unimodal ionomer, or a modified bimodal ionomer.

6. The golf ball of claim 1, wherein said outer cover layer comprises a blend composition comprising one or more ionomers blended with; A) one or more triblock copolymers; or B) one or more hydrogenation products of the triblock copolymers; or C) one or more hydrogenated diene block copolymers; and wherein each triblock copolymer has (i) a first polymer block comprising an aromatic vinyl compound, (ii) a second polymer block comprising a conjugated diene compound, and wherein each hydrogenated diene block copolymer has a polystyrene-reduced number-average molecular weight of from 50,000 to 600,000, and is a hydrogenation product of; (a) an A-B block copolymer, in which A is an alkenyl aromatic compound polymer block, and B is either (1) a conjugated diene homopolymer block, wherein the vinyl content of the conjugated diene portion is more than 60%, or (2) an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15-60%, or (b) an A-B-C block copolymer, in which A and B are as defined above and C is an alkenyl aromatic compound-conjugated diene copolymer tapered block, wherein the proportion of the alkenyl aromatic compound increases gradually, or (c) an A-B-A block copolymer, in which A and B are as defined above, and wherein in each of the hydrogenated diene block copolymers, the weight proportion of the alkenyl aromatic compound to conjugated diene is from 5/95 to 60/40, the content of the bound alkenyl aromatic compound in at least one block A is at least 3% by weight, the total of the bound alkenyl aromatic compound contents in the two block A's or the block A and the block C is 5% to 25% by weight based on the total monomers, and at least 80% of the double bond unsaturations of the conjugated diene portion is saturated by the hydrogenation.

7. The golf ball of claim 1, wherein the outer cover layer comprises the reaction product of: A) at least one component A comprising a monomer, oligomer, or prepolymer, or polymer comprising at least 5% by weight of at least one type of functional group; B) at least one component B comprising a monomer, oligomer, prepolymer, or polymer comprising less by weight of anionic functional groups than the weight percentage of anionic functional groups of the at least one component A; and C) at least one component C comprising a metal cation, wherein the reaction product comprises a pseudo-crosslinked network of the at least one component A in the presence of the at least one component B.

8. A golf ball comprising; A) a central core; B) one or more mantle layers; and C) an outer cover layer wherein one or more of said core or said one or more mantle layers is coated with successive coats of different coating compositions, the first applied coat comprising an epoxy resin coating composition and the second applied coat comprising a polyurethane resin coating composition.

9. The golf ball of claim 8 wherein one or more of said mantle layers comprises a polymer selected from the group consisting of natural rubbers, synthetic rubbers, thermoset polyurethanes, thermoset polyureas, thermoplastic polyurethanes, thermoplastic polyureas, metallocene catalyzed polymers, maleic anhydride grafted metallocene polymers, unimodal ethylene/carboxylic acid copolymers, unimodal ethylene/carboxylic acid/carboxylate terpolymers, bimodal ethylene/carboxylic acid copolymers, bimodal ethylene/carboxylic acid/carboxylate terpolymers, polyamides, copolyamides, polyesters, copolyesters, polycarbonates, polyolefins, halogenated polyolefins, halogenated polyalkylenes, polyalkenamer, polyphenylene oxides, polyphenylene sulfides, diallyl phthalate polymers, polyimides, polyvinyl chlorides, polyamide-ionomers, polyurethane-ionomers, polyvinyl alcohols, polyarylates, polyacrylates, polyphenylene ethers, impact-modified polyphenylene ethers, polystyrenes, high impact polystyrenes, acrylonitrile-butadiene-styrene copolymers, styrene-acrylonitriles (SAN), acrylonitrile-styrene-acrylonitriles, styrene-maleic anhydride (S/MA) polymers, styrenic block copolymers, functionalized styrenic block copolymers cellulosic polymers, liquid crystal polymers (LCP), ethylene-propylene-diene terpolymers (EPDM), ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymers, propylene elastomers, ethylene vinyl acetates, polysiloxanes, and any and all combinations thereof.

10. The golf ball of claim 8 wherein one or more of said mantle layers comprises greater than 85% by weight of a polyalkenamer rubber selected from the group consisting of polybutenamer rubber, polypentenamer rubber, polyhexenamer rubber, polyheptenamer rubber, polyoctenamer rubber, polynonenamer rubber, polydecenamer rubber polyundecenamer rubber, polydodecenamer rubber, polytridecenamer rubber and any and all combinations thereof.

11. The golf ball of claim 10 wherein one or more of said mantle layers comprises greater than 90% by weight of a polyalkenamer rubber selected from the group consisting of polypentenamer rubber, polyoctenamer rubber, polydodecenamer rubber and any and all combinations thereof.

12. The golf ball of claim 8 wherein the outer cover layer comprises a thermoplastic elastomer, a polyalkenamer composition, a thermoset polyurethane, a thermoplastic polyurethane, a thermoset polyurea, a thermoplastic polyurea, a polyamide, a unimodal ionomer, a bimodal ionomer, a modified unimodal ionomer, or a modified bimodal ionomer.

13. The golf ball of claim 8, wherein said outer cover layer comprises a blend composition comprising one or more ionomers blended with; A) one or more triblock copolymers; or B) one or more hydrogenation products of the triblock copolymers; or C) one or more hydrogenated diene block copolymers; and wherein each triblock copolymer has (i) a first polymer block comprising an aromatic vinyl compound, (ii) a second polymer block comprising a conjugated diene compound, and wherein each hydrogenated diene block copolymer has a polystyrene-reduced number-average molecular weight of from 50,000 to 600,000, and is a hydrogenation product of; (a) an A-B block copolymer, in which A is an alkenyl aromatic compound polymer block, and B is either (1) a conjugated diene homopolymer block, wherein the vinyl content of the conjugated diene portion is more than 60%, or (2) an alkenyl aromatic compound-conjugated diene random copolymer block wherein the vinyl content of the conjugated diene portion is 15-60%, or (b) an A-B-C block copolymer, in which A and B are as defined above and C is an alkenyl aromatic compound-conjugated diene copolymer tapered block, wherein the proportion of the alkenyl aromatic compound increases gradually, or (c) an A-B-A block copolymer, in which A and B are as defined above, and wherein in each of the hydrogenated diene block copolymers, the weight proportion of the alkenyl aromatic compound to conjugated diene is from 5/95 to 60/40, the content of the bound alkenyl aromatic compound in at least one block A is at least 3% by weight, the total of the bound alkenyl aromatic compound contents in the two block A's or the block A and the block C is 5% to 25% by weight based on the total monomers, and at least 80% of the double bond unsaturations of the conjugated diene portion is saturated by the hydrogenation.

14. The golf ball of claim 8, wherein the outer cover layer comprises the reaction product of: A) at least one component A comprising a monomer, oligomer, or prepolymer, or polymer comprising at least 5% by weight of at least one type of functional group; B) at least one component B comprising a monomer, oligomer, prepolymer, or polymer comprising less by weight of anionic functional groups than the weight percentage of anionic functional groups of the at least one component A; and C) at least one component C comprising a metal cation, wherein the reaction product comprises a pseudo-crosslinked network of the at least one component A in the presence of the at least one component B.

15. A method for making a golf ball comprising: coating onto at least one of a golf ball core or one or more golf ball mantle layers a coating composition wherein the coating composition includes a polysulfide silane; a waterborne polyurethane resin composition; a waterborne urethane modified acrylic resin composition; an epoxy resin composition; or a combination or mixture thereof.

16. The method of claim 15, wherein the coating composition is coated onto the golf ball core.

17. The method of claim 15, wherein the coating composition is coated onto a golf ball mantle layer.

18. The method of claim 15, wherein the coating composition is coated onto the golf ball core and onto a golf ball mantle layer.

19. The method of claim 18, wherein the coating composition coated onto the golf ball core is different compared to the coating composition coated onto the golf ball mantle layer.

20. The method of claim 15 wherein the core or the mantle layer is coated with successive coats of different coating compositions, the first applied coat comprising an epoxy resin coating composition and the second applied coat comprising a polyurethane resin coating composition.

Description:

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 61/746,536, which was filed on Dec. 27, 2012 and is incorporated herein by reference in its entirety.

BACKGROUND

The application of synthetic polymer chemistry to the field of sports equipment has revolutionized the performance of athletes in many sports. One sport in which this is particularly true is golf, especially as relates to advances in golf ball performance and ease of manufacture. For instance, the earliest golf balls consisted of a leather cover filled with wet feathers. These “feathery” golf balls were subsequently replaced with a single piece golf ball made from “gutta percha,” a naturally occurring rubber-like material. In the early 1900's, the wound rubber ball was introduced, consisting of a solid rubber core around which rubber thread was tightly wound with a gutta percha cover.

More modern golf balls can be classified as one-piece, two-piece, three-piece or multi-layered golf balls. One-piece balls are molded from a homogeneous mass of material with a dimple pattern molded thereon. One-piece balls are inexpensive and very durable, but do not provide great distance because of relatively high spin and low velocity. Two-piece balls are made by molding a cover around a solid rubber core. These are the most popular types of balls in use today. In attempts to further modify the ball performance, especially in terms of the distance such balls travel and the feel transmitted to the golfer through the club on striking the ball, the basic two piece ball construction has been further modified by the introduction of additional layers between the core and outer cover layer. If one additional layer is introduced between the core and outer cover layer a so called “three-piece ball” results and similarly if two additional layers are introduced between the core and outer cover layer, a so called “four-piece ball” results, and so on. In addition, so called “dual core” balls have been made in which the central rubber core is made from two discrete sections of the synthetic rubber material each section having different properties such as compression, resilience, hardness and durability. Even more recently, balls have been introduced having both dual cores and additional thin intermediate layers between the dual core and outer cover layer.

After core formation, any intermediate layers and finally the golf ball outer cover are typically formed over the core using one of three methods: casting, injection molding, or compression molding. Injection molding generally involves using a mold having one or more sets of two hemispherical mold sections that mate to form a spherical cavity during the molding process. The pairs of mold sections are configured to define a spherical cavity in their interior when mated. When used to mold an outer cover layer for a golf ball, the mold sections can be configured so that the inner surfaces that mate to form the spherical cavity include protrusions configured to form dimples on the outer surface of the molded cover layer.

In contrast, compression molding of a ball cover or intermediate layer typically requires the initial step of making half shells by injection molding the layer material into an injection mold. The half shells then are positioned in a compression mold around a ball core, whereupon heat and pressure are used to mold the half shells into a complete layer over the core, with or without a chemical reaction such as crosslinking. Compression molding also can be used as a curing step after injection molding. In such a process, an outer layer of thermally curable material is injection molded around a core in a cold mold. After the material solidifies, the ball is removed and placed into a mold, in which heat and pressure are applied to the ball to induce curing in the outer layer.

Of the various cover molding processes, injection molding is most preferred, due to the efficiencies gained by its use including a more rapid cycle time, cheaper operating costs and an improved ability to produce thinner layers around the core and closely control any thickness variation. This latter advantage is becoming more important with the developments of multi-layered balls with two or more intermediate layers between the core and cover thus requiring thinner layer formation.

Among the most common materials used in modern golf ball construction include polybutadiene which is typically utilized in golf ball core formation, ionomers which are often utilized in both golf ball intermediate layer and outer cover layer preparation, and thermoplastic and thermoset polyurethanes and polyureas which are most often utilized in golf ball outer cover layer preparation.

In addition to the polybutadiene-based synthetic rubbers typically used in golf ball core formation, another family of synthetic rubber available for use in golf balls are the so-called polyalkenamers. These synthetic rubbers are unique in that in addition to a liner polymeric component, they also contain a significant fraction of cyclic oligomer molecules, which in turn lowers their viscosity. Compounds of this class can be produced in accordance with the teachings of U.S. Pat. Nos. 3,804,803, 3,974,092 and 4,950,826, the entire contents of all of which are herein incorporated by reference.

To date, this material has been utilized primarily in blends with other polymers. For instance, U.S. Pat. No. 4,183,876 describes compositions comprising 15-95 parts by weight crystalline polyolefin resin and correspondingly 85-5 parts by weight cross-linked polyalkenamer rubber per 100 total parts by weight of resin and rubber. The resulting moldable thermoplastic compositions were said to exhibit improved strength and greater toughness and impact resistance than similar compositions containing substantially uncross-linked rubber. U.S. Pat. No. 4,840,993 describes a polyamide molding compound consisting of a mixture of 60 to 98% by weight of a polyamide and 2 to 40% by weight of a polyalkenamer, wherein the mixture is treated at elevated temperatures with 0.05 to 5% by weight of an organic radical source. No mention was made of the use of such compositions in balls including golf balls.

However, there a number of applications of polyalkenamer blends in game balls of various kinds. For example, U.S. Pat. No. 5,460,367 describes a pressureless tennis ball comprising a blend of trans-polyoctenamer rubber and natural rubber or other synthetic rubbers, e.g. cis-1,4-polybutadiene, trans-polybutadiene, polyisoprene, styrene-butadiene rubber, ethylene-propylene rubber or an ethylene-propylene-diene rubber (EPDM).

Also, U.S. Pat. No. 4,792,141 describes a golf ball comprising a core and a cover wherein the cover is formed from a composition comprising about 97 to about 60 parts balata and about 3 to about 40 parts by weight polyoctenylene rubber based on 100 parts by weight polymer in the composition. This patent also discloses that using more than about 40 parts by weight of polyoctenylene based on 100 parts by weight polymer in the composition has been found to produce deleterious effects.

More recently, U.S. Pat. No. 7,528,196 and copending US Pub. No. 2009/0191981A1 both to Taylor Made Golf Co. describe golf balls having cores and intermediate layers which comprise a polyalkenamer or polyalkenamer/polyamide blend composition. Similarly, U.S. Pat. No. 7,874,940 and copending US Pub. No. 2010/0323818A1 also assigned to Taylor Made Golf Co. discloses golf balls having intermediate layers comprising a polyalkenamer and methods for their preparation. Also, copending US Pub. No. 2010/0160079A1 also assigned to Taylor Made Golf Co. discloses polyalkenamer compositions (and golf ball therefrom) which are modified with for example carboxyl-functionalized diene polymers or their metal salts.

Use of these polyalkenamer compositions in golf ball layers provides injection moldable rubber compositions with the soft feel of a rubber such as balata, but of sufficiently low viscosity to allow the material to be injection molded. Another advantage of these compositions is that their properties can also be tailored by crosslinking reactions which utilize the ubiquitous formulation chemistry developed through the use of crosslinked polybutadiene compositions used in core construction.

Thus, multilayered golf balls are often fabricated with chemically distinct layers including ionomers, polyurethane, synthetic rubber compositions including polybutadienes and more recently polyalkenamers. This allows the production of golf balls having various combinations of hardness, modulus and other properties in order to tailor the resulting principal performance categories, including ball velocity, compression, spin and distance. However, one difficulty common to preparing solid multilayer balls with chemically distinct layers is that materials of an outer layer do not necessarily bond well with the materials used in the inner layer(s). This can result in layer separation, particularly when the golf ball is struck by a club, which can detrimentally affect the playability and appearance of the golf ball. Moreover, should the cover be cut or damaged, improper bonding between layers tends to permit further degradation of the cover or even complete disintegration of the ball layers.

Various types of surface treatment techniques are known for use in modifying polymer surfaces to improve adhesion between layers. These techniques include mechanical abrasion; chemical abrasion, such as etching; and high-voltage electrostatic discharge, also known as corona treatment. See, e.g., U.S. Pat. No. 5,466,424 (corona discharge surface treating method) and Stobbe, Bruce, “Corona Treatment 101,” Label and Narrow Web Indus., May-June, 1996. Another method of modifying polymer surfaces is plasma treating. Plasma treatment of various shapes and types of polymers in general is well known. See, e.g., Kaplan, S. L., “Cold Gas Plasma Treatment for Re-Engineering Films,” Paper Film Foil Converter, 71(6) June, 1997; Rose, P., et al., “Treating Plastic Surfaces with Cold Gas Plasmas,” Plastics Engineering, pp. 41-45 (October, 1985).

The use of primers is well known in the field of paints and coatings and has been used extensively in the golf ball art to prepare golf balls for painting or printing. For example, U.S. Pat. No. 7,682,662 discloses a method of improving the adhesion between aqueous polyurethane paint and the surface of the golf ball body by first applying an aqueous solution of polycarbodiimide. U.S. Pat. No. 5,000,458 discloses the use of a transparent primer coat, comprising optical brighteners. U.S. Pat. No. 5,300,325 discloses the use of 4% to 10% of a polyfunctional aziridine in the primer to promote adhesion between the cover and top coat of a golf ball. U.S. Pat. No. 6,893,360 describes a method of surface treating a golf ball by applying a thin coat of oleic acid to the surface of a ball having been prepped with a water-based primer coat. U.S. Pat. No. 6,672,423 describes heating the cover of a golf ball from about 90° F. to about 150° F. for 1 to 3 hours in a heated enclosure prior to applying a coat of primer to the balls which are then painted while still in the heated state. Also, U.S. Pat. No. 5,817,735 discloses primer compositions over which a paint layer or clear topcoat may be applied. The primers include substantially solvent-free urethane dispersions and a substantially solvent-free acrylic having a low volatile organic content.

However, it would be extremely advantageous if new systems could be developed which improve adhesion and limit delamination in golf balls having layers comprising synthetic rubber-based formulations.

The present disclosure provides a golf ball comprising one or more layers of a synthetic rubber composition wherein the layers immediately adjacent to the synthetic rubber-based layers are coated with an adhesion promoting composition which results in the golf balls exhibiting surprisingly improved adhesion and resistance to delamination. The improved adhesion results from the use of adhesion promoter compositions based on an epoxy composition or a urethane composition or an acrylic modified urethane composition or mixtures thereof.

SUMMARY

According to one embodiment a golf ball is disclosed which includes a central core; one or more mantle layers and an outer cover layer where one or more of the core and the one or more mantle layers is coated with an adhesion promoting composition which includes one or more of the following components; a polysulfide silane; a waterborne polyurethane resin composition; a waterborne urethane modified acrylic resin composition; or an epoxy resin composition.

According to another embodiment a golf ball is disclosed which includes a central core; one or more mantle layers and an outer cover layer and where one or more of core and one or more mantle layers is coated with successive coats of different adhesion promoting compositions, the first applied coat including an epoxy resin adhesion promoting composition and the second applied coat including a polyurethane resin adhesion promoting composition. Also disclosed herein is a method for making a golf ball that includes coating onto at least one of a golf ball core or one or more golf ball mantle layers a coating composition wherein the coating composition includes a polysulfide silane; a waterborne polyurethane resin composition; a waterborne urethane modified acrylic resin composition; an epoxy resin composition; or a combination or mixture thereof.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a three-piece golf ball 1 comprising a solid center or core 2, a mantle layer 3, and an outer cover layer 4.

FIG. 2 illustrates a four-piece golf ball 1 comprising a core 2, and an outer cover layer 5, an inner mantle layer 3, and an outer mantle layer 4.

FIG. 3 illustrates a six-piece golf ball 1 comprising a core 2, and an outer cover layer 7, an inner mantle layer 3, an outer mantle layer 4, an intermediate mantle layer 5 and an inner cover layer 6.

DETAILED DESCRIPTION

The presently disclosed compositions can be used in forming golf balls of any desired size. “The Rules of Golf” by the USGA dictate that the size of a competition golf ball must be at least 1.680 inches in diameter; however, golf balls of any size can be used for leisure golf play. The preferred diameter of the golf balls is from about 1.670 inches to about 1.800 inches or about 1.680 inches to about 1.800 inches. The more preferred diameter is from about 1.680 inches to about 1.760 inches. A diameter of from about 1.680 inches to about 1.740 inches is most preferred; however diameters anywhere in the range of from 1.70 to about 2.0 inches can be used. Oversize golf balls with diameters above about 1.760 inches to as big as 2.75 inches are also within the scope of the disclosure.

Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable is from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, it is intended that values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc., are expressly enumerated in this specification. For values, which have less than one unit difference, one unit is considered to be 0.1, 0.01, 0.001, or 0.0001 as appropriate. Thus all possible combinations of numerical values between the lowest value and the highest value enumerated herein are said to be expressly stated in this application.

The singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise. The word “comprises” indicates “includes.” It is further to be understood that all molecular weight or molecular mass values given for compounds are approximate, and are provided for description. The materials, methods, and examples are illustrative only and not intended to be limiting. Unless otherwise indicated, description of components in chemical nomenclature refers to the components at the time of addition to any combination specified in the description, but does not necessarily preclude chemical interactions among the components of a mixture once mixed.

For ease of understanding, the following terms used herein are described below in more detail. The below term descriptions are provided solely to aid the reader, and should not be construed to have a scope less than that understood by a person of ordinary skill in the art or as limiting the scope of the appended claims.

The term “bimodal polymer” refers to a polymer comprising two main fractions and more specifically to the form of the polymers molecular weight distribution curve, i.e., the appearance of the graph of the polymer weight fraction as function of its molecular weight. When the molecular weight distribution curves from these fractions are superimposed into the molecular weight distribution curve for the total resulting polymer product, that curve will show two maxima or at least be distinctly broadened in comparison with the curves for the individual fractions. Such a polymer product is called bimodal. It is to be noted here that also the chemical compositions of the two fractions may be different.

As used herein, the term “block copolymer” is intended to mean a polymer comprising two or more homopolymer subunits linked by covalent bonds. The union of the homopolymer subunits may require an intermediate non-repeating subunit, known as a junction block. Block copolymers with two or three distinct blocks are called diblock copolymers and triblock copolymers, respectively.

The term “core” is intended to mean the elastic center of a golf ball. The core may be a unitary core having a center it may have one or more “core layers” of elastic material, which are usually made of rubbery material such as diene rubbers. The core may also be of a so called “dual core” construction when it is made of up of (i) an interior spherical center component formed from a thermoset material, preferably polybutadiene and (ii) a second region formed around the interior spherical center component, also formed from a thermoset material, and preferably butadiene. Although the two core regions which constitute the dual core may both be formed form polybutadiene, each region preferably has different physical properties such as resilience, hardness or modulus resulting from the use of different crosslinking packages and/or processing conditions.

The term “solid core” as used herein refers to the elastic center of a golf ball, which is a solid sphere having a geometric center and an outer surface and comprising a resilient polymer and having a unitary construction.

The term “core outer surface” as used herein refers to the outer surface of the solid core.

The term “outer cover layer” as used herein refers to the outermost cover layer of the golf ball; the layer having 1) an outer surface of the outer cover layer which is the layer that is directly in contact with paint and/or ink on the surface of the golf ball and on which the dimple pattern is formed and 2) an inner surface of the outer cover layer spaced inwardly from the outer surface towards the geometric center of the golf ball.

The term “golf ball outer surface” as used herein is the surface of the golf ball which is directly in contact with the paint and/or ink and on which the dimple pattern is placed. When the golf ball has an outer cover layer, the outer surface of the outer cover layer is also the golf ball outer surface.

The term “fiber” as used herein is a general term for which the definition given in Engineered Materials Handbook, Vol. 2, “Engineering Plastics”, published by A.S.M. International, Metals Park, Ohio, USA, is relied upon to refer to filamentary materials with a finite length that is at least 100 times its diameter, which is typically 0.10 to 0.13 mm (0.004 to 0.005 in.). Fibers can be continuous or specific short lengths (discontinuous), normally no less than 3.2 mm (⅛ in.). Although fibers according to this definition are preferred, fiber segments, i.e., parts of fibers having lengths less than the aforementioned are also considered to be encompassed by the invention. Thus, the terms “fibers” and “fiber segments” are used herein. In the claims appearing at the end of this disclosure in particular, the expression “fibers or fiber segments” and “fiber elements” are used to encompass both fibers and fiber segments.

The term “hydrocarbyl” is intended to mean any aliphatic, cycloaliphatic, aromatic, aryl substituted aliphatic, aryl substituted cycloaliphatic, aliphatic substituted aromatic, or cycloaliphatic substituted aromatic groups. The aliphatic or cycloaliphatic groups are preferably saturated. Likewise, the term “hydrocarbyloxy” means a hydrocarbyl group having an oxygen linkage between it and the carbon atom to which it is attached.

The term “mantle layer” is intended to mean any layer(s) in a golf ball disposed between the core (and any core layers) and the outer cover layer. Should a ball have three mantle layers, these may be distinguished as the “inner mantle layer” which refers to the mantle layer nearest the core and furthest from the outer cover layer, as opposed to the “outer mantle layer” which refers to the mantle layer furthest from the core and closest to the outer cover layer, and as opposed to the “intermediate mantle layer” which refers to the mantle layer between the inner mantle layer and the outer mantle layer.

The term “(meth)acrylic acid copolymers” is intended to mean copolymers of methacrylic acid and/or acrylic acid.

The term “(meth)acrylate” is intended to mean an ester of methacrylic acid and/or acrylic acid.

The term “partially neutralized” is intended to mean an ionomer with a degree of neutralization of less than 100 percent. The term “highly neutralized” is intended to mean an ionomer with a degree of neutralization of greater than 50 percent. The term “fully neutralized” is intended to mean an ionomer with a degree of neutralization of 100 percent.

The term “prepolymer” as used herein is intended to mean any polymeric material that can be further processed to form a final polymer material of a manufactured golf ball, such as, by way of example and not limitation, a polymerized or partially polymerized material that can undergo additional processing, such as crosslinking.

The term “sports equipment” refers to any item of sports equipment such as sports clothing, boots, sneakers, clogs, sandals, slip on sandals and shoes, golf shoes, tennis shoes, running shoes, athletic shoes, hiking shoes, skis, ski masks, ski boots, cycling shoes, soccer boots, golf clubs, golf bags, and the like.

The term “synthetic rubber” as used herein may include the traditional rubber components used in golf ball applications including cis-1,4-polybutadiene, trans-1,4-polybutadiene, 1,2-polybutadiene, cis-polyisoprene, trans-polyisoprene, polychloroprene, polybutylene, styrene-butadiene rubber, styrene-butadiene-styrene block copolymer and partially and fully hydrogenated equivalents, styrene-isoprene-styrene block copolymer and partially and fully hydrogenated equivalents, nitrile rubber, silicone rubber, and polyurethane, as well as mixtures of these. Polybutadiene rubbers, especially 1,4-polybutadiene rubbers containing at least 40 mol %, and more preferably 80 to 100 mol % of cis-1,4 bonds, are preferred because of their high rebound resilience, moldability, and high strength after vulcanization. The polybutadiene component may be synthesized by using rare earth-based catalysts, nickel-based catalysts, or cobalt-based catalysts, conventionally used in this field. Polybutadiene obtained by using lanthanum rare earth-based catalysts usually employ a combination of a lanthanum rare earth (atomic number of 57 to 71)-compound, but particularly preferred is a neodymium compound.

The term “thermoplastic” as used herein is intended to mean a material that is capable of softening or melting when heated and of hardening again when cooled. Thermoplastic polymer chains often are not cross-linked or are lightly crosslinked using a chain extender, but the term “thermoplastic” as used herein may refer to materials that initially act as thermoplastics, such as during an initial extrusion process or injection molding process, but which also may be crosslinked, such as during a compression molding step to form a final structure.

The term “thermoset” as used herein is intended to mean a material that crosslinks or cures via interaction with as crosslinking or curing agent. Crosslinking may be induced by energy, such as heat (generally above 200° C.), through a chemical reaction (by reaction with a curing agent), or by irradiation. The resulting composition remains rigid when set, and does not soften with heating. Thermosets have this property because the long-chain polymer molecules cross-link with each other to give a rigid structure. A thermoset material cannot be melted and re-molded after it is cured. Thus thermosets do not lend themselves to recycling unlike thermoplastics, which can be melted and re-molded.

The term “thermoplastic polyurethane” as used herein is intended to mean a material prepared by reaction of a prepared by reaction of a diisocyanate with a polyol, and optionally addition of a chain extender.

The term “thermoplastic polyurea” as used herein is intended to mean a material prepared by reaction of a prepared by reaction of a diisocyanate with a polyamine, with optionally addition of a chain extender.

The term “thermoset polyurethane” as used herein is intended to mean a material prepared by reaction of a diisocyanate with a polyol (or a prepolymer of the two), and a curing agent.

The term “thermoset polyurea” as used herein is intended to mean a material prepared by reaction of a diisocyanate with a polyamine (or a prepolymer of the two) and a curing agent.

The term “unimodal polymer” refers to a polymer comprising one main fraction and more specifically to the form of the polymers molecular weight distribution curve, i.e., the molecular weight distribution curve for the total polymer product shows only a single maximum.

The term “urethane prepolymer” as used herein is intended to mean the reaction product of diisocyanate and a polyol.

The term “urea prepolymer” as used herein is intended to mean the reaction product of a diisocyanate and a polyamine.

The term “zwitterion” as used herein is intended to mean a form of the compound having both an amine group and carboxylic acid group, where both are charged and where the net charge on the compound is neutral.

The term “injection moldable” as used herein, and as applied to the synthetic rubber compositions used as described herein refers to a material amenable to use in injection molding apparatus designed for use with typical thermoplastic resins. In one example, the term injection moldable composition as applied to the uncross linked rubbers used in the present disclosure means compositions having a viscosity using a Dynamic Mechanical Analyzer (DMA) and ASTM D4440 at 200° C. of less than about 5,000 Pa-sec, preferably less than about 3,000 Pa-sec, more preferably less than about 2,000 Pa-sec and even more preferably less than about 1,000 Pa-sec. and a storage modulus (G′) at 1 Hz measured using a Dynamic Mechanical Analyzer (DMA) and ASTM D4065, and ASTM D4440, at 25° C., and 1 Hz of greater than about 1×107 dyn/cm2, preferably greater than about 1.5×107 dyn/cm2, more preferably greater than about 1×108 dyn/cm2, and most preferably greater than about 2×108 dyn/cm2.

The term “polyalkenamer” is used interchangeably herein with the term “polyalkenamer rubber” and means a rubbery polymer of one or more cycloalkenes having from 4-20, ring carbon atoms. The polyalkenamers may be prepared by ring opening metathesis polymerization of one or more cycloalkenes in the presence of organometallic catalysts as described in U.S. Pat. Nos. 3,492,245, and 3,804,803, the entire contents of both of which are herein incorporated by reference.

The golf balls may comprise a synthetic rubber comprising an injection moldable polyalkenamer rubber. Examples of suitable polyalkenamer rubbers are polybutenamer rubber, polypentenamer rubber, polyhexenamer rubber, polyheptenamer rubber, polyoctenamer rubber, polynonenamer rubber, polydecenamer rubber polyundecenamer rubber, polydodecenamer rubber, polytridecenamer rubber. For further details concerning polyalkenamer rubber, see Rubber Chem. & Tech., Vol. 47, page 511-596, 1974, which is incorporated herein by reference. Polyoctenamer rubbers are commercially available from Huls AG of Marl, Germany, and through its distributor in the U.S., Creanova Inc. of Somerset, N.J., and sold under the trademark VESTENAMER®. Two grades of the VESTENAMER® trans-polyoctenamer are commercially available: VESTENAMER 8012 designates a material having a trans-content of approximately 80% (and a cis-content of 20%) with a melting point of approximately 54° C.; and VESTENAMER 6213 designates a material having a trans-content of approximately 60% (cis-content of 40%) with a melting point of approximately 30° C. Both of these polymers have a double bond at every eighth carbon atom in the ring.

The polyalkenamer rubbers used in the present disclosure exhibit excellent melt processability above their sharp melting temperatures and exhibit high miscibility with various rubber additives as a major component without deterioration of crystallinity which in turn facilitates injection molding. Thus, unlike synthetic polybutadiene rubbers typically used in golf ball core preparation, injection molded parts of polyalkenamer-based compounds can be prepared which, in addition, can also be partially or fully crosslinked at elevated temperature. The crosslinked polyalkenamer compounds are highly elastic, and their mechanical and physical properties can be easily modified by adjusting the formulation.

The polyalkenamer composition surprisingly exhibits superior characteristics over a broad spectrum of properties. For example, the compositions exhibit superior impact durability and Coefficient of Restitution (COR) in a pre-determined hardness range (e.g., a hardness Shore D of from about 15 to about 85, preferably from about 40 to about 80, and more preferably from about 40 to about 75. More particularly, the compositions disclosed herein exhibit excellent hardness adjustment without significantly compromising COR or processability.

The polyalkenamer rubbers may also be blended within other polymers. A more complete description of the various polyalkenamer rubber compositions and blends is disclosed in U.S. Pat. No. 7,528,196, US Pub. No. 2009/0191981A1, U.S. Pat. No. 7,874,940, US Pub. No. 2010/0323818A1 and US Pub. No. 2010/0160079A1, all assigned to Taylor Made Golf Co. and all in the name of Hyun Kim at al., the entire contents of each of which are hereby incorporated by reference.

The polyalkenamer rubber preferably contains from about 50 to about 99, preferably from about 60 to about 99, more preferably from about 65 to about 99, even more preferably from about 70 to about 90 percent of its double bonds in the trans-configuration. The preferred form of the polyalkenamer has a trans content of approximately 80%, however, compounds having other ratios of the cis- and trans-isomeric forms of the polyalkenamer can also be obtained by blending available products for use in making the composition.

The polyalkenamer rubber has a molecular weight (as measured by GPC) from about 10,000 to about 300,000, preferably from about 20,000 to about 250,000, more preferably from about 30,000 to about 200,000, even more preferably from about 50,000 to about 150,000.

The polyalkenamer rubber has a degree of crystallization (as measured by DSC secondary fusion) from about 5 to about 70, preferably from about 6 to about 50, more preferably from about from 6.5 to about 50%, even more preferably from about from 7 to about 45%.

More preferably, the polyalkenamer rubber is a polymer prepared by polymerization of cyclooctene to form a trans-polyoctenamer rubber as a mixture of linear and cyclic macromolecules.

Prior to its use in golf balls, the polyalkenamer rubber or other synthetic rubber compositions used in the present invention may be further formulated with one or more of the following blend components:

A. Crosslinking Agents

The synthetic rubber compositions may include any crosslinking or curing system typically used for rubber crosslinking. Satisfactory crosslinking systems may include those based on sulfur-, peroxide-, azide-, maleimide- or resin-vulcanization agents, which may be used in conjunction with a vulcanization accelerator. Examples of satisfactory crosslinking system components are zinc oxide, sulfur, organic peroxide, azo compounds, magnesium oxide, benzothiazole sulfenamide accelerator, benzothiazyl disulfide, phenolic curing resin, m-phenylene bis-maleimide, thiuram disulfide and dipentamethylene-thiuram hexasulfide.

More preferable crosslinking agents include peroxides, sulfur compounds, as well as mixtures of these. Non-limiting examples of suitable crosslinking agents include primary, secondary, or tertiary aliphatic or aromatic organic peroxides. Peroxides containing more than one peroxy group can be used, such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-di-(2-tert-butyl peroxyisopropyl)benzene. Both symmetrical and asymmetrical peroxides can be used, for example, tert-butyl perbenzoate and tert-butyl cumyl peroxide. Peroxides incorporating carboxyl groups also are suitable. The decomposition of peroxides used as crosslinking agents in the disclosed compositions can be brought about by applying thermal energy, shear, irradiation, reaction with other chemicals, or any combination of these. Both homolytically and heterolytically decomposed peroxide can be used. Non-limiting examples of suitable peroxides include: diacetyl peroxide; di-tert-butyl peroxide; dibenzoyl peroxide; dicumyl peroxide; 2,5-dimethyl-2,5-di(benzoylperoxy)hexane; 1,4-bis-(t-butylperoxyisopropyl)benzene; t-butylperoxybenzoate; 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, such as Trigonox 145-45B, marketed by Akrochem Corp. of Akron, Ohio; 1,1-bis(t-butylperoxy)-3,3,5 tri-methylcyclohexane, such as Varox 231-XL, marketed by R.T. Vanderbilt Co., Inc. of Norwalk, Conn.; and di-(2,4-dichlorobenzoyl)peroxide.

The crosslinking agents can be blended in total amounts of about 0.1 part to about 10, more preferably about 0.4 to about 6, and most preferably about 0.8 part to about 4 parts per 100 parts of the synthetic rubber compositions used in the present invention. The crosslinking agent(s) may be mixed directly into or with the synthetic rubber compositions, or the crosslinking agent(s) may be pre-mixed with the synthetic rubber component to form a concentrated compound prior to subsequent compounding with the bulk of the synthetic rubber compositions used in the present invention.

Each peroxide crosslinking agent has a characteristic decomposition temperature at which 50% of the crosslinking agent has decomposed when subjected to that temperature for a specified time period (t1/2). For example, 1,1-bis-(t-butylperoxy)-3,3,5-tri-methylcyclohexane at t1/2=0.1 hr has a decomposition temperature of 138° C. and 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 at t1/2=0.1 hr has a decomposition temperature of 182° C. Two or more crosslinking agents having different characteristic decomposition temperatures at the same t1/2 may be blended in the composition. For example, where at least one crosslinking agent has a first characteristic decomposition temperature less than 150° C., and at least one crosslinking agent has a second characteristic decomposition temperature greater than 150° C., the composition weight ratio of the at least one crosslinking agent having the first characteristic decomposition temperature to the at least one crosslinking agent having the second characteristic decomposition temperature can range from 5:95 to 95:5, or more preferably from 10:90 to 50:50.

Besides the use of chemical crosslinking agents, exposure of the synthetic rubber compositions to radiation also can serve as a crosslinking agent. Radiation can be applied to the synthetic rubber compositions by any known method, including using microwave or gamma radiation, or an electron beam device. Additives may also be used to improve radiation-induced crosslinking of the synthetic rubber composition.

B. Co-Crosslinking Agent

The synthetic rubber compositions used in the present invention may also be blended with a co-crosslinking agent, which may be an unsaturated carboxylic acid, or a metal salt thereof. Examples of these include zinc and magnesium salts of unsaturated fatty acids having 3 to 8 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid, palmitic acid with the zinc salts of acrylic and methacrylic acid being most preferred. The unsaturated carboxylic acid metal salt can be blended in the synthetic rubber compositions either as a preformed metal salt, or by introducing an α,β-unsaturated carboxylic acid and a metal oxide or hydroxide into the synthetic rubber composition, and allowing them to react to form the metal salt. The unsaturated carboxylic acid metal salt can be blended in any desired amount, but preferably in amounts of about 5 to about 160, more preferably from about 10 to about 150, most preferably from about 20 to about 140 parts per 100 parts of the synthetic rubber composition.

C. Peptizer

The synthetic rubber compositions may also incorporate one or more of the so-called “peptizers”. The peptizer preferably comprises an organic sulfur compound and/or its metal or non-metal salt. Examples of such organic sulfur compounds include thiophenols, such as pentachlorothiophenol, 4-butyl-o-thiocresol, 4 t-butyl-p-thiocresol, and 2-benzamidothiophenol; thiocarboxylic acids, such as thiobenzoic acid; 4,4′dithio dimorpholine; and, sulfides, such as dixylyl disulfide, dibenzoyl disulfide; dibenzothiazyl disulfide; di(pentachlorophenyl)disulfide; dibenzamido diphenyldisulfide (DBDD), and alkylated phenol sulfides, such as VULTAC marketed by Atofina Chemicals, Inc. of Philadelphia, Pa. Preferred organic sulfur compounds include pentachlorothiophenol, and dibenzamido diphenyldisulfide.

Examples of the metal salt of an organic sulfur compound include sodium, potassium, lithium, magnesium calcium, barium, cesium and zinc salts of the above-mentioned thiophenols and thiocarboxylic acids, with the zinc salt of pentachlorothiophenol being most preferred.

Examples of the non-metal salt of an organic sulfur compound include ammonium salts of the above-mentioned thiophenols and thiocarboxylic acids wherein the ammonium cation has the general formula [NR1R2R3R4]+ where R1, R2, R3 and R4 are selected from the group consisting of hydrogen, a C1-C20 aliphatic, cycloaliphatic or aromatic moiety, and any and all combinations thereof, with the most preferred being the NH4+-salt of pentachlorothiophenol.

Additional peptizers include aromatic or conjugated peptizers comprising one or more heteroatoms, such as nitrogen, oxygen and/or sulfur. More typically, such peptizers are heteroaryl or heterocyclic compounds having at least one heteroatom, and potentially plural heteroatoms, where the plural heteroatoms may be the same or different. Such peptizers include peptizers such as an indole peptizer, a quinoline peptizer, an isoquinoline peptizer, a pyridine peptizer, purine peptizer, a pyrimidine peptizer, a diazine peptizer, a pyrazine peptizer, a triazine peptizer, a carbazole peptizer, or combinations of such peptizers.

Suitable peptizers also may include one or more additional functional groups, such as halogens, particularly chlorine; a sulfur-containing moiety exemplified by thiols, where the functional group is sulfhydryl (—SH), thioethers, where the functional group is —SR, disulfides, (R1S—SR2), etc.; and combinations of functional groups. Such peptizers are more fully disclosed in copending U.S. Application No. 60/752,475 filed on Dec. 20, 2005 in the name of Hyun Kim et al, the entire contents of which are herein incorporated by reference. A most preferred example is 2,3,5,6-tetrachloro-4-pyridinethiol (TCPT).

The peptizer, if employed in the synthetic rubber formulations used to prepare the golf balls, is present in an amount up to about 10, from about 0.1 to about 10, preferably of from about 0.5 to about 8, more preferably of from about 1 to about 6 parts by weight per 100 parts by weight of the synthetic rubber component.

D. Accelerators

The synthetic rubber compositions can also comprise one or more accelerators of one or more classes. Accelerators are added to an unsaturated polymer to increase the vulcanization rate and/or decrease the vulcanization temperature. Accelerators can be of any class known for rubber processing including mercapto-, sulfenamide-, thiuram, dithiocarbamate, dithiocarbamyl-sulfenamide, xanthate, guanidine, amine, thiourea, and dithiophosphate accelerators. Specific commercial accelerators include 2-mercaptobenzothiazole and its metal or non-metal salts, such as Vulkacit Mercapto C, Mercapto MGC, Mercapto ZM-5, and ZM marketed by Bayer AG of Leverkusen, Germany, Nocceler M, Nocceler MZ, and Nocceler M-60 marketed by Ouchisinko Chemical Industrial Company, Ltd. of Tokyo, Japan, and MBT and ZMBT marketed by Akrochem Corporation of Akron, Ohio. A more complete list of commercially available accelerators is given in The Vanderbilt Rubber Handbook: 13th Edition (1990, R.T. Vanderbilt Co.), pp. 296-330, in Encyclopedia of Polymer Science and Technology, Vol. 12 (1970, John Wiley & Sons), pp. 258-259, and in Rubber Technology Handbook (1980, Hanser/Gardner Publications), pp. 234-236. Preferred accelerators include 2-mercaptobenzothiazole (MBT) and its salts.

The synthetic rubber composition can further incorporate from about 0.1 part to about 10 parts by weight of the accelerator per 100 parts by weight of the synthetic rubber. More preferably, the ball composition can further incorporate from about 0.5 part to about 8 parts, and most preferably from about 1 part to about 6 parts, by weight of the accelerator per 100 parts by weight of the synthetic rubber.

Adhesion Promoting Compound (“APC”)

The APC used in the golf balls may be a bifunctional compound including both sulfide and silane functionality including for example, polysufide silanes including di-sulfide silane and tetra-sulfide silane. Examples of commercially available polysulfide silanes include the various silane coupling agents used for rubber compounding and sold by the Struktol Company of America including for example those sold under the brand names SCA 98 and SCA 985, SCA 989 and SCA 1100.

Also included as APC's are waterborne resin compositions containing a polyurethane resin, which can be prepared by, for example, subjecting a high-molecular-weight polyol compound, an organic polyisocyanate compound, and, as needed, a chain-extending agent to a urethane-forming reaction in a solvent with good affinity for water that is inert with respect to the reaction to obtain a prepolymer; neutralizing the prepolymer; and dispersing it in an aqueous solvent containing a chain-extending agent to increase the molecular weight. For such waterborne polyurethane resin compositions and methods of preparing them, reference can be made to, for example, paragraphs [0009] to [0013] of Japanese Patent No. 3,588,375, paragraphs [0012] to [0021] of Japanese Unexamined Patent Publication (KOKAI) Heisei No. 8-34897, paragraphs [0010] to [0033] of Japanese Unexamined Patent Publication (KOKAI) Heisei No. 11-92653, and paragraphs [0010] to [0033] of Japanese Unexamined Patent Publication (KOKAI) Heisei No. 11-92655. The content of the above publications are expressly incorporated herein by reference in their entirety.

The waterborne polyurethane resin composition can be employed in the form of a commercially available water-based urethane as is, or diluted with an aqueous solution as needed. Examples of commercially available waterborne polyurethanes are the “Adeka Bontighter” series made by Asahi Denka Kogyo, K. K.; the “Olester” series made by Mitsui-Toatsu Chemicals, Inc.; the “Bondick” and “Hydran” series made by Dainippon Ink and Chemicals; Corporation; the “Impranil” series made by Bayer; the “Sofranate” series made by Japan Sofran; the “Poise” series made by Kao; the “Sanprene” series made by Sanyo Chemical Industries, Ltd.; the “Izelax” series made by Hodogaya Chemical Co., Ltd.; the “Superflex” series made by Daiichi Yakuhin Kougyou Co., Ltd.; and the “Neo Rez” series made by Zeneca.

Also included as APC's for use in the golf balls are waterborne acrylic resin compositions, including the fast drying urethane modified acrylic polyurethane resins. An acrylic polyurethane resin is a two-part type acrylic resin comprising acrylic polyol and isocyanate, wherein a base material containing acrylic polyol is mixed with a curing agent containing isocyanate, the subsequent addition reaction between the OH group of the acrylic polyol and an isocyanate group (NCO group) forming a compound having an urethane bond.

The acrylic polyol is a copolymer or oligomer having a plurality of hydroxyl groups, which may be obtained by copolymerizing (meth)acrylic monomer having an —OH group, e.g. β-hydroxylethyl methacrylate, with (meth)acrylic acid and/or (meth)acrylate.

The usable isocyanate preferably has two or more isocyanate groups and examples thereof include aliphatic, alicyclic, aromatic and aromatic aliphatic diisocyanate compounds, such as hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, tetramethyl xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and tolylene diisocyanate. These isocyanates may be used alone or in combination. A ratio of NCO groups to a OH groups, NCO/OH, may be determined according to the curing rate required, and is preferably in a range, for example, from 0.5 to 2.0, more preferably in a range from 0.9 to 1.5.

Further illustrative APC's for use in the golf balls include epoxy resin based coatings which may have two or more epoxy groups in the polymer chain, capable of crosslinking through the reaction with the curing agent. The epoxy resin is cured to form a chemical network structure through a crosslinking reaction with a curing agent in the case of a thermoset epoxy resin or with a free radical produced from a photosensitizer by irradiation of ultraviolet ray in the case of a photosensitized epoxy resin.

Examples of such epoxy resins used as APC's in the golf balls include thermoset epoxy resins such as a bisphenol A type epoxy resin obtained from bisphenol A and epichlorohydrin, a bisphenol F type epoxy resin, a novolac-type epoxy resin, an alicyclic-type epoxy resin, a glycidyl ester-type epoxy resin, and glycidylamine-type epoxy resin; and photosensitized epoxy resins incorporated with an acryloyl group or a methacryloyl group to enhance their photosensitivity.

In certain embodiments, a preferable epoxy resin has a hydroxyl value of not less than 50, more preferably not less than 100, further preferably not less than 150, particularly not less than 180. The upper limit of the hydroxyl value of the epoxy resin is preferably not more than 300, more preferably not more than 250, further preferably not more than 195. The term “hydroxyl value” as used herein is a value serving as an indication of the amount of hydroxyl groups contained in an epoxy resin. Specifically, the hydroxyl value means the amount in “mg” of potassium hydroxide required to neutralize an acetyl group in acetic acid resulting from saponification of an acetylated compound.

The curing agent to be used for curing the thermoset epoxy resin may be any basic or acidic compound which has a plurality of active hydrogen atoms to react the epoxy group or which catalyzes ring opening of the epoxide. Examples of such curing agents include amines, acid anhydrides, isocyanate compounds, resol-type phenolic resins, melamine resins, and urea resins. Among them, isocyanate compounds are preferably employed.

Examples of specific amines for use as the curing agent include aliphatic amines such as ethylenediamine, 1,3-diaminopropane, 1,4-diaminopropane, and hexamethylenediamine; aliphatic polyamines such as diethylenetriamine, imino-bis-propylamine, and triethylenetetramine; and aromatic amines such as methaphenylenediamine, diaminodiphenylmethane, and diaminodiethyldiphenylmethane.

Examples of specific acid anhydrides for use as the curing agent include aliphatic acid anhydrides such as dodecenylsuccinic anhydride, polyadipic anhydride, polyazelaic anhydride, and polysebacic anhydride; alicyclic acid anhydrides such as methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, and tetrahydrophthalic anhydride; aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride; and halogen-based acid anhydrides such as HET anhydride.

The isocyanate compound preferably has two or more isocyanate groups. Examples of such isocyanate compounds include aliphatic, alicyclic, aromatic or aromatic aliphatic diisocyanate compounds such as hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, tetramethylxylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and tolylene diisocyanate. Among them, hexamethylene diisocyanate is preferred in terms of the durability of a resulting mark made from the cured ink and the adherence of the cured ink to the clear coat put on the mark.

Curing agents for use in combination with the APC's also include polyfunctional aziridine crosslinker materials, preferably tri- or more highly functional compounds. The preferred materials include: pentaerythritol-tris-(β-(N-aziridinyl) propionate); trimethylol-propane-tris-(β-(N-aziridinyl)propionate); mixtures of different polyfunctional aziridines identified in U.S. Pat. No. 5,057,371 (for example, from column 3, line 45 to column 5 line 19); the polyaziridine materials identified in U.S. Pat. Nos. 5,091,239 and 4,842,950; and other polyfunctional aziridines. The patents listed in this paragraph are hereby incorporated herein by reference in their entireties to exemplify polyfunctional aziridines. Representative polyfunctional aziridines which are useful herein are sold under the trade designations CX-100; XAMA-2; and XAMA-7 by the manufacturers listed in the patents previously incorporated by reference.

An especially preferred combination of APC's includes a combination where the first applied coat comprises an epoxy resin-based adhesion promoter and the second applied coat comprises a waterborne polyurethane resin-based adhesion promoter.

Additional Polymer Components

The golf balls may have layers which comprise one or more of the following additional polymers as one or more of the components of the golf balls either alone or as blend components. These polymers include, without limitation, natural rubbers, thermoset polymers such as thermoset polyurethanes or thermoset polyureas, as well as thermoplastic polymers including thermoplastic elastomers such as thermoplastic polyurethanes or thermoplastic polyureas, metallocene catalyzed polymers, unimodal ethylene/carboxylic acid copolymers, unimodal ethylene/carboxylic acid/carboxylate terpolymers, bimodal ethylene/carboxylic acid copolymers, bimodal ethylene/carboxylic acid/carboxylate terpolymers, polyamides, copolyamides, polyesters, copolyesters, polycarbonates, polyolefins, halogenated polyolefins, such as halogenated polyethylene [e.g. chlorinated polyethylene (CPE)], halogenated polyalkylene compounds, polyalkenamer, polyphenylene oxides, polyphenylene sulfides, diallyl phthalate polymers, polyimides, polyvinyl chlorides, polyamide-ionomers, polyurethane-ionomers, polyvinyl alcohols, polyarylates, polyacrylates, polyphenylene ethers, impact-modified polyphenylene ethers, polystyrenes, high impact polystyrenes, acrylonitrile-butadiene-styrene copolymers, styrene-acrylonitriles (SAN), acrylonitrile-styrene-acrylonitriles, styrene-maleic anhydride (S/MA) polymers, styrenic block copolymers including styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene. (SITS) and styrene-ethylene-propylene-styrene (SEM, styrenic terpolymers, functionalized styrenic block copolymers including hydroxylated, functionalized styrenic copolymers, and terpolymers, cellulosic polymers, liquid crystal polymers (LCP), ethylene-propylene-diene terpolymers (EPDM), ethylene-vinyl acetate copolymers (EVA), ethylene-propylene copolymers, propylene elastomers (such as those described in U.S. Pat. No. 6,525,157, to Kim et al, the entire contents of which is hereby incorporated by reference in its entirety), ethylene vinyl acetates and polysiloxanes, and any and all combinations thereof. Also included are the various grafted polymers including a maleic anhydride-grafted non-ionomeric polymer including maleic anhydride grafted polyolefins. A particularly suitable maleic anhydride-grafted polymer is Fusabond from DuPont, which is a maleic anhydride-grafted, metallocene-catalyzed ethylene-butene copolymer having about 0.9 wt % maleic anhydride grafted onto the copolymer.

One preferred material which may be used as a component of the outer cover layer and/or intermediate layers of the golf balls comprises a blend of an ionomer and a block copolymer. Examples of such block copolymers include styrenic block copolymers including styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene, (SEBS) and styrene-ethylene/propylene-styrene (SEPS). Also included are functionalized styrenic block copolymers, including those where the block copolymer incorporates a first polymer block having an aromatic vinyl compound, a second polymer block having a conjugated diene compound and a hydroxyl group located at a block copolymer, or its hydrogenation product, and in which the ratio of block copolymer to ionomer ranges from 5:95 to 95:5 by weight, more preferably from about 10:90 to about 90:10 by weight, more preferably from about 20:80 to about 80:20 by weight, more preferably from about 30:70 to about 70:30 by weight and most preferably from about 35:65 to about 65:35 by weight. A preferred functionalized styrenic block copolymer is SEPTON HG-252. Such blends are described in more detail in commonly-assigned U.S. Pat. No. 6,861,474 and U.S. Patent Publication No. 2003/0224871 both of which are incorporated herein by reference in their entireties.

Another preferred material for the outer cover and/or intermediate layers of the golf balls is a composition prepared by blending together at least three materials, identified as Components A, B, and C, and melt-processing these components to form in-situ, a polymer blend composition incorporating a pseudo-crosslinked polymer network. Such blends are described in more detail in commonly-assigned U.S. Pat. No. 6,930,150, to Kim et al, the content of which is incorporated by reference herein in its entirety. Component A is a monomer, oligomer, prepolymer or polymer that incorporates at least five percent by weight of at least one type of an acidic functional group. Examples of such polymers suitable for use as include, but are not limited to, ethylene/(meth)acrylic acid copolymers and ethylene/(meth)acrylic acid/alkyl (meth)acrylate terpolymers, or ethylene and/or propylene maleic anhydride copolymers and terpolymers. Examples of such polymers which are commercially available include, but are not limited to, the ESCOR® 5000, 5001, 5020, 5050, 5070, 5100, 5110 and 5200 series of ethylene-acrylic acid copolymers sold by Exxon and the PRIMACOR® 1321, 1410, 1410-XT, 1420, 1430, 2912, 3150, 3330, 3340, 3440, 3460, 4311, 4608 and 5980 series of ethylene-acrylic acid copolymers sold by The Dow Chemical Company, Midland, Mich. and the ethylene-acrylic acid copolymers Nucrel 599, 699, 0903, 0910, 925, 960, 2806, and 2906 ethylene-methacrylic acid copolymers. sold by DuPont Also included are the bimodal ethylene/carboxylic acid polymers as described in U.S. Pat. No. 6,562,906, the contents of which are incorporated herein by reference. These polymers comprise ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid high copolymers, particularly ethylene (meth)acrylic acid copolymers and ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers, having molecular weights of about 80,000 to about 500,000 which are melt blended with ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers, particularly ethylene/(meth)acrylic acid copolymers having molecular weights of about 2,000 to about 30,000.

Component B can be any monomer, oligomer, or polymer, preferably having a lower weight percentage of anionic functional groups than that present in Component A in the weight ranges discussed above, and most preferably free of such functional groups. Examples of materials for use as Component B include block copolymers such as styrenic block copolymers including styrene-butadiene-styrene (SBS), styrene-ethylene-butylene-styrene, (SEBS) and styrene-ethylene/propylene-styrene (SEPS). Also included are functionalized styrenic block copolymers, including those where the block copolymer incorporates a first polymer block having an aromatic vinyl compound, a second polymer block having a conjugated diene compound and a hydroxyl group located at a block copolymer, or its hydrogenation product. Commercial examples SEPTON marketed by Kuraray Company of Kurashiki, Japan; TOPRENE by Kumho Petrochemical Co., Ltd and KRATON marketed by Kraton Polymers.

Component C is a base capable of neutralizing the acidic functional group of Component A and is a base having a metal cation. These metals are from groups IA, IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VB, VIA, VIB, VIIB and VIIIB of the periodic table. Examples of these metals include lithium, sodium, magnesium, aluminum, potassium, calcium, manganese, tungsten, titanium, iron, cobalt, nickel, hafnium, copper, zinc, barium, zirconium, and tin. Suitable metal compounds for use as a source of Component C are, for example, metal salts, preferably metal hydroxides, metal oxides, metal carbonates, or metal acetates.

The composition preferably is prepared by mixing the above materials into each other thoroughly, either by using a dispersive mixing mechanism, a distributive mixing mechanism, or a combination of these. These mixing methods are well known in the manufacture of polymer blends. As a result of this mixing, the anionic functional group of Component A is dispersed evenly throughout the mixture. Most preferably, Components A and B are melt-mixed together without Component C, with or without the premixing discussed above, to produce a melt-mixture of the two components. Then, Component C separately is mixed into the blend of Components A and B. This mixture is melt-mixed to produce the reaction product. This two-step mixing can be performed in a single process, such as, for example, an extrusion process using a proper barrel length or screw configuration, along with a multiple feeding system.

Another preferred material for the outer cover and/or one or intermediate layers of the golf balls is a blend of a homopolyamide or copolyamide and a polymer including a grafted maleic anhydride group.

Another preferred material which may be used as a component of the outer cover layer and/or intermediate layer of the golf balls is the family of polyurethanes or polyureas which are typically prepared by reacting a diisocyanate with a polyol (in the case of polyurethanes) or with a polyamine (in the case of a polyurea). Thermoplastic polyurethanes or polyureas may consist solely of this initial mixture or may be further combined with a chain extender to vary properties such as hardness of the thermoplastic. Thermoset polyurethanes or polyureas typically are formed by the reaction of a diisocyanate and a polyol or polyamine respectively, and an additional crosslinking agent to crosslink or cure the material to result in a thermoset.

In what is known as a one-shot process, the three reactants, diisocyanate, polyol or polyamine, and optionally a chain extender or a curing agent, are combined in one step. Alternatively, a two-step process may occur in which the first step involves reacting the diisocyanate and the polyol (in the case of polyurethane) or the polyamine (in the case of a polyurea) to form a so-called prepolymer, to which can then be added either the chain extender or the curing agent. This procedure is known as the prepolymer process.

In addition, although depicted as discrete component packages as above, it is also possible to control the degree of crosslinking, and hence the degree of thermoplastic or thermoset properties in a final composition, by varying the stoichiometry not only of the diisocyanate-to-chain extender or curing agent ratio, but also the initial diisocyanate-to-polyol or polyamine ratio. Of course in the prepolymer process, the initial diisocyanate-to-polyol or polyamine ratio is fixed on selection of the required prepolymer.

In addition to discrete thermoplastic or thermoset materials, it also is possible to modify thermoplastic polyurethane or polyurea compositions by introducing materials in the composition that undergo subsequent curing after molding the thermoplastic to provide properties similar to those of a thermoset. For example, Kim in U.S. Pat. No. 6,924,337, the entire contents of which are hereby incorporated by reference, discloses a thermoplastic urethane or urea composition optionally comprising chain extenders and further comprising a peroxide or peroxide mixture, which can then undergo post curing to result in a thermoset.

Also, Kim et al. in U.S. Pat. No. 6,939,924, the entire contents of which are hereby incorporated by reference, discloses a thermoplastic urethane or urea composition, optionally also comprising chain extenders, that are prepared from a diisocyanate and a modified or blocked diisocyanate which unblocks and induces further cross linking post extrusion. The modified isocyanate preferably is selected from the group consisting of: isophorone diisocyanate (IPDI)-based uretdione-type crosslinker; a combination of a uretdione adduct of IPDI and a partially e-caprolactam-modified IPDI; a combination of isocyanate adducts modified by e-caprolactam and a carboxylic acid functional group; a caprolactam-modified Desmodur diisocyanate; a Desmodur diisocyanate having a 3,5-dimethyl pyrazole modified isocyanate; or mixtures of these.

Finally, Kim et al. in U.S. Pat. No. 7,037,985 B2, the entire contents of which are hereby incorporated by reference, discloses thermoplastic urethane or urea compositions further comprising a reaction product of a nitroso compound and a diisocyanate or a polyisocyanate. The nitroso reaction product has a characteristic temperature at which it decomposes to regenerate the nitroso compound and diisocyanate or polyisocyanate. Thus, by judicious choice of the post-processing temperature, further crosslinking can be induced in the originally thermoplastic composition to provide thermoset-like properties.

Any isocyanate available to one of ordinary skill in the art is suitable for use in the polyurethanes or polyureas. Isocyanates include, but are not limited to, aliphatic, cycloaliphatic, aromatic aliphatic, aromatic, any derivatives thereof, and combinations of these compounds having two or more isocyanate (NCO) groups per molecule. As used herein, aromatic aliphatic compounds should be understood as those containing an aromatic ring, wherein the isocyanate group is not directly bonded to the ring. One example of an aromatic aliphatic compound is a tetramethylene diisocyanate (TMXDI). The isocyanates may be organic polyisocyanate-terminated prepolymers, low free isocyanate prepolymer, and mixtures thereof. The isocyanate-containing reactable component also may include any isocyanate-functional monomer, dimer, trimer, or polymeric adduct thereof, prepolymer, quasi-prepolymer, or mixtures thereof. Isocyanate-functional compounds may include monoisocyanates or polyisocyanates that include any isocyanate functionality of two or more.

Suitable isocyanate-containing components include diisocyanates having the generic structure: O═C═N—R—N═C═O, where R preferably is a cyclic, aromatic, or linear or branched hydrocarbon moiety containing from about 1 to about 50 carbon atoms. The isocyanate also may contain one or more cyclic groups or one or more phenyl groups. When multiple cyclic or aromatic groups are present, linear and/or branched hydrocarbons containing from about 1 to about 10 carbon atoms can be present as spacers between the cyclic or aromatic groups. In some cases, the cyclic or aromatic group(s) may be substituted at the 2-, 3-, and/or 4-positions, or at the ortho-, meta-, and/or para-positions, respectively. Substituted groups may include, but are not limited to, halogens, primary, secondary, or tertiary hydrocarbon groups, or a mixture thereof.

Examples of isocyanates include, but are not limited to, substituted and isomeric mixtures including 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanate (MDI); 3,3′-dimethyl-4,4′-biphenylene diisocyanate (TODI); toluene diisocyanate (TDI); polymeric MDI; carbodiimide-modified liquid 4,4′-diphenylmethane diisocyanate; para-phenylene diisocyanate (PPDI); meta-phenylene diisocyanate (MPDI); triphenyl methane-4,4′- and triphenyl methane-4,4″-triisocyanate; naphthylene-1,5-diisocyanate; 2,4′-, 4,4′-, and 2,2-biphenyl diisocyanate; polyphenylene polymethylene polyisocyanate (PMDI) (also known as polymeric PMDI); mixtures of MDI and PMDI; mixtures of PMDI and TDI; ethylene diisocyanate; propylene-1,2-diisocyanate; trimethylene diisocyanate; butylenes diisocyanate; bitolylene diisocyanate; tolidine diisocyanate; tetramethylene-1,2-diisocyanate; tetramethylene-1,3-diisocyanate; tetramethylene-1,4-diisocyanate; pentamethylene diisocyanate; 1,6-hexamethylene diisocyanate (HDI); octamethylene diisocyanate; decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; dicyclohexylmethane diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate; diethylidene diisocyanate; methylcyclohexylene diisocyanate (HTDI); 2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate; 4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate; 1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexane diisocyanate; 4,4′-bis(isocyanatomethyl)dicyclohexane; 2,4′-bis(isocyanatomethyl)dicyclohexane; isophorone diisocyanate (IPDI); dimeryl diisocyanate, dodecane-1,12-diisocyanate, 1,10-decamethylene diisocyanate, cyclohexylene-1,2-diisocyanate, 1,10-decamethylene diisocyanate, 1-chlorobenzene-2,4-diisocyanate, furfurylidene diisocyanate, 2,4,4-trimethyl hexamethylene diisocyanate, 2,2,4-trimethyl hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,3-cyclobutane diisocyanate, 1,4-cyclohexane diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate), 4,4′-methylenebis(phenyl isocyanate), 1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane diisocyanate, 1,3-bis(isocyanato-methyl)cyclohexane, 1,6-diisocyanato-2,2,4,4-tetra-methylhexane, 1,6-diisocyanato-2,4,4-tetra-trimethylhexane, trans-cyclohexane-1,4-diisocyanate, 3-isocyanato-methyl-3,5,5-trimethylcyclo-hexyl isocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, cyclohexyl isocyanate, dicyclohexylmethane 4,4′-diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, m-phenylene diisocyanate, m-xylylene diisocyanate, m-tetramethylxylylene diisocyanate, p-phenylene diisocyanate, p,p′-biphenyl diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, 3,3′-diphenyl-4,4′-biphenylene diisocyanate, 4,4′-biphenylene diisocyanate, 3,3′-dichloro-4,4′-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, metaxylene diisocyanate, 2,4-toluene diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,4-chlorophenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, p,p′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2-diphenylpropane-4,4′-diisocyanate, 4,4′-toluidine diisocyanate, dianidine diisocyanate, 4,4′-diphenyl ether diisocyanate, 1,3-xylylene diisocyanate, 1,4-naphthylene diisocyanate, azobenzene-4,4′-diisocyanate, diphenyl sulfone-4,4′-diisocyanate, triphenylmethane 4,4′,4″-triisocyanate, isocyanatoethyl methacrylate, 3-isopropenyl-α,α-dimethylbenzyl-isocyanate, dichlorohexamethylene diisocyanate, ω, ω′-diisocyanato-1,4-diethylbenzene, polymethylene polyphenylene polyisocyanate, isocyanurate modified compounds, and carbodiimide modified compounds, as well as biuret modified compounds of the above polyisocyanates. These isocyanates may be used either alone or in combination. These combination isocyanates include triisocyanates, such as biuret of hexamethylene diisocyanate and triphenylmethane triisocyanates, and polyisocyanates, such as polymeric diphenylmethane diisocyanate.triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate (TMDI); 4,4′-dicyclohexylmethane diisocyanate (H12MDI); 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; 1,2-, 1,3-, and 1,4-phenylene diisocyanate; aromatic aliphatic isocyanate, such as 1,2-, 1,3-, and 1,4-xylene diisocyanate; meta-tetramethylxylene diisocyanate (m-TMXDI); para-tetramethylxylene diisocyanate (p-TMXDI); trimerized isocyanurate of any polyisocyanate, such as isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate of hexamethylene diisocyanate, and mixtures thereof, dimerized uretdione of any polyisocyanate, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and mixtures thereof; modified polyisocyanate derived from the above isocyanates and polyisocyanates; and mixtures thereof.

Suitable polyols include, but are not limited to, polyester polyols, polyether polyols, polycarbonate polyols and polydiene polyols such as polybutadiene polyols.

Any polyamine available to one of ordinary skill in the polyurethane art is suitable. Suitable polyamines include, but are not limited to, amine-terminated compounds typically are selected from amine-terminated hydrocarbons, amine-terminated polyethers, amine-terminated polyesters, amine-terminated polycaprolactones, amine-terminated polycarbonates, amine-terminated polyamides, and mixtures thereof. The amine-terminated compound may be a polyether amine selected from polytetramethylene ether diamines, polyoxypropylene diamines, poly(ethylene oxide capped oxypropylene) ether diamines, triethyleneglycoldiamines, propylene oxide-based triamines, trimethylolpropane-based triamines, glycerin-based triamines, and mixtures thereof.

The diisocyanate and polyol or polyamine components may be combined to form a prepolymer prior to reaction with a chain extender or curing agent. Any such prepolymer combination is suitable.

One preferred prepolymer is a toluene diisocyanate prepolymer with polypropylene glycol. Such polypropylene glycol terminated toluene diisocyanate prepolymers are available from Uniroyal Chemical Company of Middlebury, Conn., under the trade name ADIPRENE® LFG963A and LFG640D. Most preferred prepolymers are the polytetramethylene ether glycol terminated toluene diisocyanate prepolymers including those available from Uniroyal Chemical Company of Middlebury, Conn., under the trade name ADIPRENE® LF930A, LF950A, LF601D, and LF751D.

In one embodiment, the number of free NCO groups in the urethane or urea prepolymer may be less than about 14 percent. Preferably the urethane or urea prepolymer has from about 3 percent to about 11 percent, more preferably from about 4 to about 9.5 percent, and even more preferably from about 3 percent to about 9 percent, free NCO on an equivalent weight basis.

Polyol chain extenders or curing agents may be primary, secondary, or tertiary polyols. Non-limiting examples of monomers of these polyols include: trimethylolpropane (TMP), ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 2,5-hexanediol, 2,4-hexanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, and 2-ethyl-2-(hydroxymethyl)-1,3-propanediol.

Diamines and other suitable polyamines may be added to the compositions to function as chain extenders or curing agents. These include primary, secondary and tertiary amines having two or more amines as functional groups. Exemplary diamines include aliphatic diamines, such as tetramethylenediamine, pentamethylenediamine, hexamethylenediamine; alicyclic diamines, such as 3,3′-dimethyl-4,4′-diamino-dicyclohexyl methane; or aromatic diamines, such as diethyl-2,4-toluenediamine, 4,4″-methylenebis-(3-chloro,2,6-diethyl)-aniline (available from Air Products and Chemicals Inc., of Allentown, Pa., under the trade name LONZACURE®), 3,3′-dichlorobenzidene; 3,3′-dichloro-4,4′-diaminodiphenyl methane (MOCA); N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine, 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; N,N′-dialkyldiamino diphenyl methane; trimethylene-glycol-di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate, 4,4′-methylene bis-2-chloroaniline, 2,2′,3,3′-tetrachloro-4,4′-diamino-phenyl methane, p,p′-methylenedianiline, p-phenylenediamine or 4,4′-diaminodiphenyl; and 2,4,6-tris(dimethylaminomethyl) phenol.

Depending on their chemical structure, curing agents may be slow- or fast-reacting polyamines or polyols. As described in U.S. Pat. Nos. 6,793,864, 6,719,646 and copending U.S. Patent Publication No. 2004/0201133 A1, (the contents of all of which are hereby incorporated herein by reference), slow-reacting polyamines are diamines having amine groups that are sterically and/or electronically hindered by electron withdrawing groups or bulky groups situated proximate to the amine reaction sites. The spacing of the amine reaction sites will also affect the reactivity speed of the polyamines.

Suitable curatives selected from the slow-reacting polyamine group include, but are not limited to, 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; N,N′-dialkyldiamino diphenyl methane; trimethylene-glycol-di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate, and mixtures thereof. Of these, 3,5-dimethylthio-2,4-toluenediamine and 3,5-dimethylthio-2,6-toluenediamine are isomers and are sold under the trade name ETHACURE® 300 by Ethyl Corporation. Trimethylene glycol-di-p-aminobenzoate is sold under the trade name POLACURE 740M and polytetramethyleneoxide-di-p-aminobenzoates are sold under the trade name POLAMINES by Polaroid Corporation. N,N′-dialkyldiamino diphenyl methane is sold under the trade name UNILINK® by UOP.

Also included as a curing agent for use in the polyurethane or polyurea compositions are the family of dicyandiamides as described in copending application Ser. No. 11/809,432 filed on May 31, 2007 by Kim et al., the entire contents of which are hereby incorporated by reference.

The outer cover layer and/or intermediate layers of the golf balls may also comprise one or more ionomer resins. One family of such resins were developed in the mid-1960's, by E.I. DuPont de Nemours and Co., and sold under the trademark SURLYN®. Preparation of such ionomers is well known, for example see U.S. Pat. No. 3,264,272. Generally speaking, most commercial ionomers are unimodal and consist of a polymer of a mono-olefin, e.g., an alkene, with an unsaturated mono- or dicarboxylic acids having 3 to 12 carbon atoms. An additional monomer in the form of a mono- or dicarboxylic acid ester may also be incorporated in the formulation as a so-called “softening comonomer”. The incorporated carboxylic acid groups are then neutralized by a basic metal ion salt, to form the ionomer. The metal cations of the basic metal ion salt used for neutralization include Li+, Na+, K+, Zn2+, Ca2+, Co2+, Ni2+, Cu2+, Pb2+, and Mg2+, with the Li+, Na+, Ca2+, Zn2+, and Mg2+ being preferred. The basic metal ion salts include those of for example formic acid, acetic acid, nitric acid, and carbonic acid, hydrogen carbonate salts, oxides, hydroxides, and alkoxides.

The first commercially available ionomer resins contained up to 16 weight percent acrylic or methacrylic acid, although it was also well known at that time that, as a general rule, the hardness of these cover materials could be increased with increasing acid content. Hence, in Research Disclosure 29703, published in January 1989, DuPont disclosed ionomers based on ethylene/acrylic acid or ethylene/methacrylic acid containing acid contents of greater than 15 weight percent. In this same disclosure, DuPont also taught that such so called “high acid ionomers” had significantly improved stiffness and hardness and thus could be advantageously used in golf ball construction, when used either singly or in a blend with other ionomers.

More recently, high acid ionomers are typically defined as those ionomer resins with acrylic or methacrylic acid units present from 16 wt. % to about 35 wt. % in the polymer. Generally, such a high acid ionomer will have a flexural modulus from about 50,000 psi to about 125,000 psi.

Ionomer resins further comprising a softening comonomer, present from about 10 wt. % to about 50 wt. % in the polymer, have a flexural modulus from about 2,000 psi to about 10,000 psi, and are sometimes referred to as “soft” or “very low modulus” ionomers. Typical softening comonomers include n-butyl acrylate, iso-butyl acrylate, n-butyl methacrylate, methyl acrylate and methyl methacrylate.

Today, there are a wide variety of commercially available ionomer resins based both on copolymers of ethylene and (meth)acrylic acid or terpolymers of ethylene and (meth)acrylic acid and (meth)acrylate, all of which many of which are be used as a golf ball component. The properties of these ionomer resins can vary widely due to variations in acid content, softening comonomer content, the degree of neutralization, and the type of metal ion used in the neutralization. The full range commercially available typically includes ionomers of polymers of general formula, E/X/Y polymer, wherein E is ethylene, X is a C3 to C8 α,β ethylenically unsaturated carboxylic acid, such as acrylic or methacrylic acid, and is present in an amount from about 2 to about 30 weight % of the E/X/Y copolymer, and Y is a softening comonomer selected from the group consisting of alkyl acrylate and alkyl methacrylate, such as methyl acrylate or methyl methacrylate, and wherein the alkyl groups have from 1-8 carbon atoms, Y is in the range of 0 to about 50 weight % of the E/X/Y copolymer, and wherein the acid groups present in said ionomeric polymer are partially neutralized with a metal selected from the group consisting of zinc, sodium, lithium, calcium, magnesium, and combinations thereof.

E/X/Y, where E is ethylene, X is a softening comonomer such as present in an amount of from 0 wt. % to about 50 wt. % of the polymer, and Y is present in an amount from about 5 wt. % to about 35 wt. % of the polymer, and wherein the acid moiety is neutralized from about 1% to about 90% to form an ionomer with a cation such as lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc or aluminum, or a combination of such cations.

The ionomer may also be a so-called bimodal ionomer as described in U.S. Pat. No. 6,562,906 (the entire contents of which are herein incorporated by reference). These ionomers are bimodal as they are prepared from blends comprising polymers of different molecular weights. Specifically they include bimodal polymer blend compositions comprising:

    • a) a high molecular weight component having a weight average molecular weight, Mw, of about 80,000 to about 500,000 and comprising one or more ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers and/or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers; said high molecular weight component being partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and a mixture of any these; and
    • b) a low molecular weight component having a weight average molecular weight, Mw, of about from about 2,000 to about 30,000 and comprising one or more ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers and/or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers; said low molecular weight component being partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and a mixture of any these.

In addition to the unimodal and bimodal ionomers, also included are the so-called “modified ionomers” examples of which are described in U.S. Pat. Nos. 6,100,321, 6,329,458 and 6,616,552 and U.S. Patent Publication US 2003/0158312 A1, the entire contents of all of which are herein incorporated by reference.

The modified unimodal ionomers may be prepared by mixing:

    • a) an ionomeric polymer comprising ethylene, from 5 to 25 weight percent (meth)acrylic acid, and from 0 to 40 weight percent of a (meth)acrylate monomer, said ionomeric polymer neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, magnesium, and a mixture of any of these; and
    • b) from about 5 to about 40 weight percent (based on the total weight of said modified ionomeric polymer) of one or more fatty acids or metal salts of said fatty acid, the metal selected from the group consisting of calcium, sodium, zinc, potassium, and lithium, barium and magnesium and the fatty acid preferably being stearic acid.

The modified bimodal ionomers, which are ionomers derived from the earlier described bimodal ethylene/carboxylic acid polymers (as described in U.S. Pat. No. 6,562,906, the entire contents of which are herein incorporated by reference), are prepared by mixing:

    • a) a high molecular weight component having a weight average molecular weight, Mw, of about 80,000 to about 500,000 and comprising one or more ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers and/or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers; said high molecular weight component being partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, potassium, magnesium, and a mixture of any of these; and
    • b) a low molecular weight component having a weight average molecular weight, Mw, of about from about 2,000 to about 30,000 and comprising one or more ethylene/α, β-ethylenically unsaturated C3-8 carboxylic acid copolymers and/or one or more ethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers; said low molecular weight component being partially neutralized with metal ions selected from the group consisting of lithium, sodium, zinc, calcium, potassium, magnesium, and a mixture of any of these; and
    • c) from about 5 to about 40 weight percent (based on the total weight of said modified ionomeric polymer) of one or more fatty acids or metal salts of said fatty acid, the metal selected from the group consisting of calcium, sodium, zinc, potassium and lithium, barium and magnesium and the fatty acid preferably being stearic acid.

The fatty or waxy acid salts utilized in the various modified ionomers are composed of a chain of alkyl groups containing from about 4 to 75 carbon atoms (usually even numbered) and characterized by a —COOH terminal group. The generic formula for all fatty and waxy acids above acetic acid is CH3 (CH2)x COOH, wherein the carbon atom count includes the carboxyl group. The fatty or waxy acids utilized to produce the fatty or waxy acid salts modifiers may be saturated or unsaturated, and they may be present in solid, semi-solid or liquid form.

Examples of suitable saturated fatty acids, i.e., fatty acids in which the carbon atoms of the alkyl chain are connected by single bonds, include but are not limited to stearic acid (C18, i.e., CH3 (CH2)16 COOH), palmitic acid (C16, i.e., CH3 (CH2)14 COOH), pelargonic acid (C9, i.e., CH3 (CH2)7 COOH) and lauric acid (C12, i.e., CH3 (CH2)10 OCOOH). Examples of suitable unsaturated fatty acids, i.e., a fatty acid in which there are one or more double bonds between the carbon atoms in the alkyl chain, include but are not limited to oleic acid (C13, i.e., CH3 (CH2)7 CH:CH(CH2)7 COOH).

The source of the metal ions used to produce the metal salts of the fatty or waxy acid salts used in the various modified ionomers are generally various metal salts which provide the metal ions capable of neutralizing, to various extents, the carboxylic acid groups of the fatty acids. These include the sulfate, carbonate, acetate and hydroxylate salts of zinc, barium, calcium and magnesium.

Since the fatty acid salts modifiers comprise various combinations of fatty acids neutralized with a large number of different metal ions, several different types of fatty acid salts may be utilized in the invention, including metal stearates, laureates, oleates, and palmitates, with calcium, zinc, sodium, lithium, potassium and magnesium stearate being preferred, and calcium and sodium stearate being most preferred.

The fatty or waxy acid or metal salt of said fatty or waxy acid is present in the modified ionomeric polymers in an amount of from about 5 to about 40, preferably from about 7 to about 35, more preferably from about 8 to about 20 weight percent (based on the total weight of said modified ionomeric polymer).

As a result of the addition of the one or more metal salts of a fatty or waxy acid, from about 40 to 100, preferably from about 50 to 100, more preferably from about 70 to 100 percent of the acidic groups in the final modified ionomeric polymer composition are neutralized by a metal ion.

An example of such a modified ionomer polymer is DuPont® HPF-1000 available from E. I DuPont de Nemours and Co. Inc.

Fillers

The various polymeric compositions used to prepare the golf balls also can incorporate one or more fillers. Such fillers are typically in a finely divided form, for example, in a size generally less than about 20 mesh, preferably less than about 100 mesh U.S. standard size, except for fibers and flock, which are generally elongated. Filler particle size will depend upon desired effect, cost, ease of addition, and dusting considerations. The appropriate amounts of filler required will vary depending on the application but typically can be readily determined without undue experimentation.

The filler preferably is selected from the group consisting of precipitated hydrated silica, limestone, clay, talc, asbestos, barytes, glass fibers, aramid fibers, mica, calcium metasilicate, barium sulfate, zinc sulfide, lithopone, silicates, silicon carbide, diatomaceous earth, carbonates such as calcium or magnesium or barium carbonate, sulfates such as calcium or magnesium or barium sulfate, metals, including tungsten, steel, copper, cobalt or iron, metal alloys, tungsten carbide, metal oxides, metal stearates, and other particulate carbonaceous materials, and any and all combinations thereof. Preferred examples of fillers include metal oxides, such as zinc oxide and magnesium oxide. In another preferred aspect the filler comprises a continuous or non-continuous fiber. In another preferred aspect the filler comprises one or more so called nanofillers, as described in U.S. Pat. No. 6,794,447 and copending U.S. patent application Ser. No. 10/670,090 filed on Sep. 24, 2003 and copending U.S. patent application Ser. No. 10/926,509 filed on Aug. 25, 2004, the entire contents of each of which are incorporated herein by reference.

Inorganic nanofiller material generally is made of clay, such as hydrotalcite, phyllosilicate, saponite, hectorite, beidellite, stevensite, vermiculite, halloysite, mica, montmorillonite, micafluoride, or octosilicate. To facilitate incorporation of the nanofiller material into a polymer material, either in preparing nanocomposite materials or in preparing polymer-based golf ball compositions, the clay particles generally are coated or treated by a suitable compatibilizing agent. The compatibilizing agent allows for superior linkage between the inorganic and organic material, and it also can account for the hydrophilic nature of the inorganic nanofiller material and the possibly hydrophobic nature of the polymer. Compatibilizing agents may exhibit a variety of different structures depending upon the nature of both the inorganic nanofiller material and the target matrix polymer. Non-limiting examples include hydroxy-, thiol-, amino-, epoxy-, carboxylic acid-, ester-, amide-, and siloxy-group containing compounds, oligomers or polymers. The nanofiller materials can be incorporated into the polymer either by dispersion into the particular monomer or oligomer prior to polymerization, or by melt compounding of the particles into the matrix polymer. Examples of commercial nanofillers are various Cloisite grades including 10A, 15A, 20A, 25A, 30B, and NA+ of Southern Clay Products (Gonzales, Tex.) and the Nanomer grades including 1.24TL and C.30EVA of Nanocor, Inc. (Arlington Heights, Ill.).

Nanofillers when added into a matrix polymer, such as the polyalkenamer rubber, can be mixed in three ways. In one type of mixing there is dispersion of the aggregate structures within the matrix polymer, but on mixing no interaction of the matrix polymer with the aggregate platelet structure occurs, and thus the stacked platelet structure is essentially maintained. As used herein, this type of mixing is defined as “undispersed”.

However, if the nanofiller material is selected correctly, the matrix polymer chains can penetrate into the aggregates and separate the platelets, and thus when viewed by transmission electron microscopy or x-ray diffraction, the aggregates of platelets are expanded. At this point the nanofiller is said to be substantially evenly dispersed within and reacted into the structure of the matrix polymer. This level of expansion can occur to differing degrees. If small amounts of the matrix polymer are layered between the individual platelets then, as used herein, this type of mixing is known as “intercalation”.

In some circumstances, further penetration of the matrix polymer chains into the aggregate structure separates the platelets, and leads to a complete disruption of the platelet's stacked structure in the aggregate. Thus, when viewed by transmission electron microscopy (TEM), the individual platelets are thoroughly mixed throughout the matrix polymer. As used herein, this type of mixing is known as “exfoliated”. An exfoliated nanofiller has the platelets fully dispersed throughout the polymer matrix; the platelets may be dispersed unevenly but preferably are dispersed evenly.

While not wishing to be limited to any theory, one possible explanation of the differing degrees of dispersion of such nanofillers within the matrix polymer structure is the effect of the compatibilizer surface coating on the interaction between the nanofiller platelet structure and the matrix polymer. By careful selection of the nanofiller it is possible to vary the penetration of the matrix polymer into the platelet structure of the nanofiller on mixing. Thus, the degree of interaction and intrusion of the polymer matrix into the nanofiller controls the separation and dispersion of the individual platelets of the nanofiller within the polymer matrix. This interaction of the polymer matrix and the platelet structure of the nanofiller is defined herein as the nanofiller “reacting into the structure of the polymer” and the subsequent dispersion of the platelets within the polymer matrix is defined herein as the nanofiller “being substantially evenly dispersed” within the structure of the polymer matrix.

If no compatibilizer is present on the surface of a filler such as a clay, or if the coating of the clay is attempted after its addition to the polymer matrix, then the penetration of the matrix polymer into the nanofiller is much less efficient, very little separation and no dispersion of the individual clay platelets occurs within the matrix polymer.

Physical properties of the polymer will change with the addition of nanofiller. The physical properties of the polymer are expected to improve even more as the nanofiller is dispersed into the polymer matrix to form a nanocomposite.

Materials incorporating nanofiller materials can provide these property improvements at much lower densities than those incorporating conventional fillers. For example, a nylon-6 nanocomposite material manufactured by RTP Corporation of Wichita, Kans., uses a 3% to 5% clay loading and has a tensile strength of 11,800 psi and a specific gravity of 1.14, while a conventional 30% mineral-filled material has a tensile strength of 8,000 psi and a specific gravity of 1.36. Using nanocomposite materials with lower inorganic materials loadings than conventional fillers provides the same properties, and this allows products comprising nanocomposite fillers to be lighter than those with conventional fillers, while maintaining those same properties.

Nanocomposite materials are materials incorporating up to about 20%, or from about 0.1% to about 20%, preferably from about 0.1% to about 15%, and most preferably from about 0.1% to about 10% of nanofiller reacted into and substantially dispersed through intercalation or exfoliation into the structure of an organic material, such as a polymer, to provide strength, temperature resistance, and other property improvements to the resulting composite. Descriptions of particular nanocomposite materials and their manufacture can be found in U.S. Pat. No. 5,962,553 to Ellsworth, U.S. Pat. No. 5,385,776 to Maxfield et al., and U.S. Pat. No. 4,894,411 to Okada et al. Examples of nanocomposite materials currently marketed include M1030D, manufactured by Unitika Limited, of Osaka, Japan, and 1015C2, manufactured by UBE America of New York, N.Y.

When nanocomposites are blended with other polymer systems, the nanocomposite may be considered a type of nanofiller concentrate. However, a nanofiller concentrate may be more generally a polymer into which nanofiller is mixed; a nanofiller concentrate does not require that the nanofiller has reacted and/or dispersed evenly into the carrier polymer.

The nanofiller material is added in an amount up to about 20 wt %, from about 0.1% to about 20%, preferably from about 0.1% to about 15%, and most preferably from about 0.1% to about 10% by weight (based on the final weight of the polymer matrix material) of nanofiller reacted into and substantially dispersed through intercalation or exfoliation into the structure of the polymer matrix.

If desired, the various polymer compositions used to prepare the golf balls of the present invention can additionally contain other conventional additives such as plasticizers, pigments, antioxidants, U.V. absorbers, optical brighteners, or any other additives generally employed in plastics formulation or the preparation of golf balls.

Another particularly well-suited additive for use in the various polymer compositions used to prepare the golf balls of the present invention includes compounds having the general formula:


(R2N)m—R′—(X(O)nORy)m,

where R is hydrogen, or a C1-C20 aliphatic, cycloaliphatic or aromatic systems; R′ is a bridging group comprising one or more C1-C20 straight chain or branched aliphatic or alicyclic groups, or substituted straight chain or branched aliphatic or alicyclic groups, or aromatic group, or an oligomer of up to 12 repeating units including, but not limited to, polypeptides derived from an amino acid sequence of up to 12 amino acids; and X is C or S with the proviso that when X=C, n=1 and y=1 and when X=S, n=2 and y=1. Also, m=1-3. These materials are more fully described in copending U.S. patent application Ser. No. 11/182,170, filed on Jul. 14, 2005, the entire contents of which are incorporated herein by reference.

Preferably the material is selected from the group consisting of 4,4′-methylene-bis-(cyclohexylamine)carbamate (commercially available from R.T. Vanderbilt Co., Norwalk Conn. under the tradename Diak® 4), 11-aminoundecanoicacid, 12-aminododecanoic acid, epsilon-caprolactam; omega-caprolactam, and any and all combinations thereof.

In an especially preferred aspect, a nanofiller additive component in the golf ball of the present invention is surface modified with a compatibilizing agent comprising the earlier described compounds having the general formula:


(R2N)m—R′—(X(O)nORy)m,

A most preferred aspect would be a filler comprising a nanofiller clay material surface modified with an amino acid including 12-aminododecanoic acid. Such fillers are available from Nanonocor Co. under the tradename Nanomer 1.24TL.

The filler can be blended in variable effective amounts, such as amounts of greater than 0 to at least about 80 parts, and more typically from about 10 parts to about 80 parts, by weight per 100 parts by weight of the base rubber. If desired, the rubber composition can additionally contain effective amounts of a plasticizer, an antioxidant, and any other additives generally used to make golf balls.

The polymer compositions used as a component of the golf balls may also be further modified by addition of a monomeric aliphatic and/or aromatic amide as described in copending application Ser. No. 11/592,109 filed on Nov. 1, 2006 in the name of Hyun Kim et al., the entire contents of which are hereby incorporated by reference.

Golf balls also can include, in suitable amounts, one or more additional ingredients generally employed in golf ball compositions. Agents provided to achieve specific functions, such as additives and stabilizers, can be present. Examplary suitable ingredients include colorants, antioxidants, colorants, dispersants, mold releasing agents, processing aids, fillers, and any and all combinations thereof. Although not required, UV stabilizers, or photo stabilizers such as substituted hydroxphenyl benzotriazoles may be utilized in the present invention to enhance the UV stability of the final compositions. An example of a commercially available UV stabilizer is the stabilizer sold by Ciba Geigy Corporation under the tradename TINUVIN.

Golf Ball Composition and Construction

As described above, the golf balls may include a separate and discrete solid unitary golf ball core. In one embodiment the core of the golf balls, when present, may comprise multiple core layers. The core and any layers of the golf balls may be made from material commonly used to prepare golf ball cores including, but not limited to, cis 1,4-polybutadiene rubber, syn 1,2-polybutadiene rubber, polyalkenamer rubber, ionomers, thermoplastic and thermoset polyurethanes and polyureas. A preferred material is cis 1,4-polybutadiene. The various core layers (including the central core) may each exhibit a different hardness. The difference between the center hardness and that of the next adjacent layer, as well as the difference in hardness between the various core layers may be greater than 2, preferably greater than 5, most preferably greater than 10 units of Shore D. In one preferred embodiment, the hardness of the center and each sequential layer increases progressively outwards from the center to outer core layer. In another preferred embodiment, the hardness of the center and each sequential layer decreases progressively inwards from the outer core layer to the center.

In certain embodiments the core of the golf balls may have a diameter of from about 0.5 to about 1.62, preferably from about 0.7 to about 1.60, more preferably from about 1 to about 1.58, yet more preferably from about 1.15 to about 1.54, and most preferably from about 1.20 to about 1.50 in.

In certain embodiments the core of the golf balls, if present, also may have a PGA compression of from about 10 to about 200, preferably from about 20 to about 185, more preferably from about 30 to about 180, and most preferably from about 40 to about 120. In another embodiment, the core of the balls may have a PGA compression of from about 20 to about 100, preferably from about 25 to about 90, more preferably from about 30 to about 80.

Also as described above the golf balls in certain embodiments may have a discrete and separate outer cover layer. The outer cover layer of the balls may have a thickness of about 0.01 to about 0.10, preferably from about 0.015 to about 0.08, more preferably from about 0.02 to about 0.06 in.

The outer cover layer the balls may have a hardness Shore D from about 40 to about 70, preferably from about 45 to about 70 or about 50 to about 70, more preferably from 47 to about 68 or about 45 to about 70, and most preferably from about 50 to about 65.

The golf balls of the present invention may also have additional mantle layers. The golf ball may comprise from 0 to 5, preferably from 0 to 4, more preferably from 1 to 5, and most preferably from 1 to 4 such intermediate layer(s).

In certain embodiments the COR of the golf balls may be greater than about 0.760, preferably greater than about 0.780, more preferably greater than 0.790, most preferably greater than 0.795, and especially greater than 0.800 at 125 ft/sec inbound velocity. In another embodiment, the COR of the golf balls may be greater than about 0.760, preferably greater than about 0.780, more preferably greater than 0.790, most preferably greater than 0.795, and especially greater than 0.800 at 143 ft/sec inbound velocity.

Method of Making the Golf Balls

The synthetic rubber compositions used to form the layers of the golf balls can be prepared using any commonly used mixing methods. For instance, the synthetic rubber composition, and crosslinking agents, fillers and the like can be mixed together with or without melting them. Dry blending equipment, such as a tumble mixer, V-blender, ribbon blender, or two-roll mill, can be used to mix the compositions. The synthetic rubber compositions can also be mixed using a mill, internal mixer such as a Banbury or Farrel continuous mixer, extruder or combinations of these, with or without application of thermal energy to produce melting. The various components can be mixed together with the crosslinking agents, or each additive can be added in an appropriate sequence to the milled unsaturated polymer. In another method of manufacture the crosslinking agents and other components can be added to the unsaturated polymer as part of a concentrate using dry blending, roll milling, or melt mixing.

The compositions described herein can also be prepared by using a twin screw extruder with or without pre-mixing prior to charging to the extruder. The barrel temperature for the blending may be between about 140° C. to about 300° C., more preferably between about 160° C. to about 280° C., and most preferably between about 180° C. to about 260° C. The compounded material can be positioned readily around a golf ball core using injection molding. The barrel temperature for the injection molding may be between about 160° C. to about 280° C., more preferably between about 180° C. to about 260° C., and most preferably between about 200° C. and 260° C.

The ability of polyalkenamer rubber composition, to be injection molded and cured either subsequently by compression molding or actually during the injection molding process itself provides considerable flexibility in manufacture of the individual golf ball components.

In the case of golf balls having a separate and discrete core (and optionally additional core layers and intermediate layers), they may be prepared by initially positioning a solid preformed core in an injection-molding cavity followed by uniform injection of a polyalkenamer rubber composition, sequentially over the core, to produce layers of the required thickness and ultimately golf balls of the required diameter. Again use of a heated injection mold allows the temperature to be controlled sufficient to either partially of fully crosslink the material to yield the desired layer properties. If the material is partially cured, additional compression molding or irradiation steps may optionally be employed to complete the curing process to yield the desired properties.

Alternatively, the polyalkenamer layer may also be formed around the core or intermediate layer by first forming half shells by injection molding the polyalkenamer rubber composition, followed by a compression molding the half shells about the core or intermediate layer to effect the curing of the layers in the final ball.

Alternatively, the polyalkenamer layer may also be formed around the core or intermediate layer by first forming half shells by injection molding the polyalkenamer rubber composition, again using a heated injection mold which allows the temperature to be controlled sufficient to either partially of fully crosslink the material to yield the desired half shell properties layer properties. The resulting fully or partially cured half shells may then be compression molded around the core or core plus intermediate layer. Again, if the half shell is partially cured, the additional compression molding or irradiation steps may optionally be tailored to complete the curing process to yield the desired properties.

In addition, if radiation is used as a crosslinking agent, then the mixture comprising the unsaturated polymer and other additives can be irradiated following mixing, during forming into a part such as the core, intermediate layer, or outer cover of a ball, or after forming such part.

In addition, the present disclosure also relates to a method of preparation resulting from the combination of injection molding layers and half shells as described above.

Finally, the outer cover and any additional intermediate layers (if any) may also be formed using conventional molding techniques common used in golf ball preparation including but not limited to injection molding, casting and compression molding.

After formation of the polyalkenamer or other synthetic rubber layer in the golf ball or golf ball precursor and prior to formation of additional layers over the polyalkenamer or other synthetic rubber layer, the layer is treated with the one or more of the APC(s).

Coating of the APC on the golf ball layer may occur through any generally known coating method, such as spraying, dipping, rolling, pouring, brushing, or wiping so as to apply the APC with a uniform thickness. In an optional step, a predetermined time period may elapse between coating step and a subsequent curing step. During this time lapse, the APC may be allowed to sit in physical contact with the layer in an unreacted state. The coating material system may therefore penetrate into the layer. Curing processes for such ACPC's are known in the golf ball arts. For example, the curing step may comprise a heating step. In such embodiments, a golf ball may be heated to a temperature of at least about 35° C., or at least about 50° C., or at least about 75° C., for example. Typical heating times may be from about 5 minutes (for example, at higher temperatures) to about one hour.

EXAMPLES

The Examples are given below by way of illustration and not by way of limitation. The materials employed in were as follows:

VESTENAMER 8012 is a trademark of and commercially available from Huls AG of Marl, Germany, and through its distributor in the U.S., Creanova Inc. of Somerset, N.J., and is a trans-polyoctenamer having a trans-content of approximately 80% with a melting point of approximately 54° C.

SURLYN® 8150 is a grade of ionomer commercially available from DuPont, and is a sodium ionomer of an ethylene/methacrylic acid polymer.

SURLYN® 9150 is a grade of ionomer commercially available from DuPont, and is a zinc ionomer of an ethylene/methacrylic acid polymer.

NdBR40 is a cis-1,4-polybutadiene rubber made with a rare earth catalyst and commercially available from Enichem.

ZnO is a rubber grade zinc oxide purchased from Akrochem (Akron, Ohio).

ZDA are zinc diacrylates was purchased commercially from Sartomer under the tradenames SR416, and SR638, or Jinyang Chemical, under the tradename ZDA12.

Tetrachlorothiopyridine was purchased commercially from Jinyang Chemical.

BaSO4 is Poliwhite 200 barium sulfate purchased from Cinbar.

Varox 231-XL is 1,1-di(t-butylperoxy)-3,3,5-trimethyl-cyclohexane crosslinkinginitiator, (**40% active peroxide). This is commercially available from R.T. Vanderbilt and is made by Atofina.

Trigonox 145 is 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexyne crosslinkinginitiator, (**45% active peroxide). This is commercially available from Akzo Nobel. TAIC is triallyl isocyanurate, which is commercially available from Akrochem.

Nanomer 1.24TL is a surface treated clay nanofiller, commercially available from Nanonocor Co.

SCA 98 is a tetra-sulfide silane-based coupling agent available from THE STRUKTOL® Company of America.

SCA 1100 is a 3-aminopropyltriethoxysilane-based coating available from The STRUKTOL® Company of America.

SCA 985 is a di-sulfide silane-based coupling agent available from THE STRUKTOL® Company of America.

SCA 989 is a 3-mercaptopropyltriethoxysilane coupling agent available from THE STRUKTOL® Company of America.

Cho-Kwang W-Primer (U) is an acrylic modified aqueous urethane dispersion commercially available from ChoKwang.

Epoxy White Base is based on Bisphenol A used in combination with Epoxy White Hardener polyamine-based curing agent both commercially available from ChoKwang, and collectively “Epoxy White APC”.

Impranil DLP-R is an aqueous dispersion of an aliphatic polyurethane resin available from Bayer MaterialScience LLC.

CX-100 is a trifunctional aziridine-based crosslinker (trimethylolpropane tris(2-methyl-1-aziridinepropionate) commercially available from DSM.

Color concentrate is TiO2 with ionomer as binder.

The properties of Tensile Strength, Tensile Elongation, Flexural Strength, Flexural Modulus, PGA compression, C.O.R., Shore D hardness on both the materials and the resulting ball were conducted using the test methods as defined below.

Core or ball diameter was determined by using standard linear calipers or size gauge.

Specific gravity was determined by electronic densimeter using ASTM D-792.

Compression is measured by applying a spring-loaded force to the golf ball center, golf ball core, or the golf ball to be examined, with a manual instrument (an “Atti gauge”) manufactured by the Atti Engineering Company of Union City, N.J. This machine, equipped with a Federal Dial Gauge, Model D81-C, employs a calibrated spring under a known load. The sphere to be tested is forced a distance of 0.2 inch (5 mm) against this spring. If the spring, in turn, compresses 0.2 inch, the compression is rated at 100; if the spring compresses 0.1 inch, the compression value is rated as 0. Thus more compressible, softer materials will have lower Atti gauge values than harder, less compressible materials. Compression measured with this instrument is also referred to as PGA compression. The approximate relationship that exists between Atti or PGA compression and Riehle compression can be expressed as:


(Atti or PGA compression)=(160-Riehle Compression).

Thus, a Riehle compression of 100 would be the same as an Atti compression of 60.

Initial velocity of a golf ball after impact with a golf club is governed by the United States Golf Association (“USGA”). The USGA requires that a regulation golf ball can have an initial velocity of no more than 250 feet per second±2% or 255 feet per second. The USGA initial velocity limit is related to the ultimate distance that a ball may travel (280 yards±6%), and is also related to the coefficient of restitution (“COR”). The coefficient of restitution is the ratio of the relative velocity between two objects after direct impact to the relative velocity before impact. As a result, the COR can vary from 0 to 1, with 1 being equivalent to a perfectly or completely elastic collision and 0 being equivalent to a perfectly plastic or completely inelastic collision. Since a ball's COR directly influences the ball's initial velocity after club collision and travel distance, golf ball manufacturers are interested in this characteristic for designing and testing golf balls. One conventional technique for measuring COR uses a golf ball or golf ball subassembly, air cannon, and a stationary steel plate. The steel plate provides an impact surface weighing about 100 pounds or about 45 kilograms. A pair of ballistic light screens, which measure ball velocity, are spaced apart and located between the air cannon and the steel plate. The ball is fired from the air cannon toward the steel plate over a range of test velocities from 50 ft/s to 180 ft/sec. As the ball travels toward the steel plate, it activates each light screen so that the time at each light screen is measured. This provides an incoming time period proportional to the ball's incoming velocity. The ball impacts the steel plate and rebounds though the light screens, which again measure the time period required to transit between the light screens. This provides an outgoing transit time period proportional to the ball's outgoing velocity. The coefficient of restitution can be calculated by the ratio of the outgoing transit time period to the incoming transit time period, COR=TOut/Tin.

A “Mooney” viscosity is a unit used to measure the plasticity of raw or unvulcanized rubber. The plasticity in a Mooney unit is equal to the torque, measured on an arbitrary scale, on a disk in a vessel that contains rubber at a temperature of 100° C. and rotates at two revolutions per minute. The measurement of Mooney viscosity is defined according to ASTM D-1646.

Shore D material hardness was measured in accordance with ASTM Test D2240. Hardness of a layer was measured on the ball, and if on the outer surface, perpendicular to a land area between the dimples. Unless a material hardness is specified all hardnesses are measured on the ball.

The ball performance may be determined using a Robot Driver Test, which utilized a commercial swing robot in conjunction with an optical system to measure ball speed, launch angle, and backspin after a golf ball is hit with a titanium driver or standard 8 iron as applicable. In this test, club is attached to a swing robot and the swing speed and power profile as well as tee location and club lie angle is setup to generate the following values using the following set up conditions and reference balls:

175 mph: Titleist ProV1x, Ball Speed: 175 mph, Launch Angle: 12 deg, Backspin: 2600 rpm

160 mph: TaylorMade TP Red, Ball Speed: 160 mph, Launch Angle: 12 deg, Backspin: 2600 rpm

8 Iron: TaylorMade TP Red, Ball Speed: 110 mph, Launch Angle: 20 deg, Backspin: 7100 rpm

Then, the test ball was substituted for the reference ball and the corresponding values for 175 mph Driver Spin and Driver Speed, 160 mph Driver Spin and Driver Speed and 8 Iron Spin determined.

Shear cut resistance was determined by examining the balls after they were impacted by a pitching wedge at controlled speed, classifying each numerically from 1 (excellent) to 5 (poor), and averaging the results for a given ball type. Three samples of each Example was used for this testing. Each ball was hit twice, to collect two impact data points per ball. Then, each ball was assigned two numerical scores-one for each impact—from 1 (no visible damage) to 5 (substantial material displaced). These scores were then averaged for each Example to produce the shear resistance numbers below. These numbers could then be directly compared with the corresponding number for a commercially available ball, the Taylor Made TP Black under the same test conditions, had a rating of 1.62.

Tensile Strength was measured in accordance with ASTM Test D 368.

Tensile Elongation was measured in accordance with ASTM Test D 368.

Flexural Modulus was measured in accordance with ASTM Test D 790.

The Qualitative Adhesion Test was performed on sample spheres aged for 2 weeks after either injection molding of an ionomer outer layer or casting a thermoset polyurethane outer layer. The adhesion was tested by cutting the sphere into quarters and peeling by hand the outer layer from the spherical substrate and comparing the adhesion of each sample quantitatively. A scale of 1-3 based on the ease of peeling was developed where a score of 1 indicated little or no adhesion, a score of 2 indicated some adhesion) and a score of 3 indicated strong adhesion as difficult to peel.

The Quantitative Adhesion Test was performed by fixturing a golf ball in an Instron instrument and a test strip was pulled upwards at a consistent rate of 30 mm/min for 1 minute (see FIG. 1). The maximum load sensed by a 1 Kg load cell was measured and recorded. A second measurement, the average load measured over a user-defined integral, was also calculated and recorded. The qualitative results from these measurements parallel the quantitative data shown previously in Table 3.

Examples of the invention are given below by way of illustration and not by way of limitation.

Preparation of Samples 1-7

Sample 1—Polyalkenamer Spherical Substrate Preparation—A series of unitary spheres of 1.48 in diameter were prepared by mixing Vestenamer 8012 polyoctenamer, zinc oxide, SR638 zinc diacrylate, terachlorothiopyridine and Varox 231L peroxide, to produce a spherical substrate for adhesion testing having a core having a diameter of 1.48 in. An outer layer of an ethylene/acrylic acid-based zinc ionomer having an acid content of 15 wt %, and neutralized to a level of 40% and having a thickness of 0.05 in in and a hardness of 57 D was then injection molded around the spherical substrate. After allowing to age at room temperature for two weeks, the resulting sample was subjected to the Qualitative Adhesion Test.
Sample 2—Sample 2 was prepared as for Sample 1 using the same substrate and outer layer but prior to injection molding of the ionomer outer layer, the polyalkenamer sphere was then completely immersed or dipped in the water-based APC acrylic modified urethane Cho-Kwang W-Primer (U). The sample was then air dried and subjected to the Qualitative Adhesion Test, the results of which are summarized in Table 1.
Sample 3—Sample 3 was prepared as for Sample 2 but the APC used was the Epoxy White Base bisphenol-A-based epoxy mixed with Epoxy White Hardener polyamine curing agent at a weight ratio of 50:50 and the mixture was then diluted with ethyl acetate.
Sample 4—Sample 4 was prepared as for Sample 2 but the APC used was the Stuktrol® SCA 98 primer.
Sample 5—Sample 5 was prepared as for Sample 2 but the primer used was the Stuktrol® SCA 1100 primer.
Sample 6—Sample 6 was prepared as for Sample 2 but the primer used was the Stuktrol® SCA 985 primer.
Sample 7—Sample 7 was prepared as for Sample 2 but the primer used was the Stuktrol® SCA 989 primer.

TABLE 1
Evaluation of Adhesion Between Polyalkenamer Mantle with
Ionomer Cover Using Various Adhesion Promoting Agents:
Sam-Sam-Sam-Sam-Sam-Sam-
ple 2ple 3ple 4ple 5ple 6ple 7
Sam-ChoEpoxySCASCASCASCA
ple 1KwangWhite981100985989
No APCW APCAPCAPCAPCAPCAPC
Qualitative1231221
Adhesion
Test Score

Analysis of the data in Table 1 demonstrates the adhesion between a polyalkenamer-based mantle and an ionomer-based outer layer is improved when the Cho-Kwang acrylic modified aqueous urethane APC or Silane SCA1100, or Silane SCA985 APC's were applied. The best adhesion was observed with the Epoxy White APC system. The control with no priming agents showed low adhesion between the polyalkenamer-based mantle and an ionomer-based outer layer.

Comparative Example 1 and Examples 1-8

Comparative Example 1

A golf ball was prepared by first forming a unitary solid core made from a standard process that includes mixing the polybutadiene core material with a peroxide/zinc diacrylate-based crosslinking package in a two roll mill, extruding the mixture, and then forming and curing the core under heat and pressure in a compression molding cycle to yield a core having a diameter of 1.48 in. a specific gravity of 1.19 and a PGA compression of 45. Two half cups were then injection molded from a syntheti rubber mixture of Vestenamer 8012 polyoctenamer, zinc oxide, SR638 zinc diacrylate, terachlorothiopyridine and Varox 231L peroxide, having a thickness of 0.054 in. The half cups were then formed into a layer surrounding the preformed core by curing under heat and pressure in a compression molding cycle sufficient to result in a layer having an on the ball hardness of approximately 55 D. An outer layer of an ethylene/acrylic acid-based zinc ionomer having an acid content of 15 wt %, and neutralized to a level of 40% having a thickness of 0.05 in in and a hardness of 57D was then injection molded around the spherical core/mantle precursor to yield a golf ball having a diameter of 1.68 in. After allowing to age at room temperature for two weeks, the resulting ball was subjected to the Qualitative Adhesion Test and the results are summarized in Table 2 below.

Example 1

A golf ball was prepared as for Comparative Example 1 using the same spherical core/mantle precursor but prior to injection molding of the ionomer outer layer, a paint booth sprayer was used to apply Epoxy White APC. The Epoxy White Base bisphenol-A-based epoxy was mixed with the Epoxy White Hardener polyamine curing agent at a weight ratio of 50:50. This mixture was then diluted with ethyl acetate to arrive at a Zhan cup viscosity of 14 seconds and this solution was then loaded into the paint sprayer reservoir and the ball sprayed for sufficient time and in sufficient amount to result in the sample having a wet weight of 100 mg after application of the priming agent. The sample was initially dried for 15 minutes at 175 deg F and then air-dried until the tackiness of the epoxy was removed (approx. 4 hours at room temp).

Example 2

A golf ball was prepared as for Example 1 but using sufficient of the Epoxy White APC to result in the sample having a wet weight of 200 mg prior to drying.

Example 3

A golf ball was prepared as for Example 1 but using sufficient of the Epoxy White APC to result in the sample having a wet weight of 100 mg prior to drying. The sample was initially dried for 15 minutes at 150° F. and then air-dried until the tackiness of the epoxy was removed (approx. 4 hours at room temp).

Example 4

A golf ball was prepared as for Example 3 but using sufficient of Epoxy White APC to result in the sample having a wet weight of 200 mg prior to drying. The sample was again initially dried for 15 minutes at 150° F. and then air-dried until the tackiness of the epoxy was removed (approx. 4 hours at room temp).

Example 5

The golf ball of Example 1 was then subjected to a post cure period after molding of the outer cover layer by heating at 130° F. for 30 mins.

Example 6

The golf ball of Example 2 was then subjected to a post cure period after molding of the outer cover layer by heating at 130° F. for 30 mins.

Example 7

The golf ball of Example 3 was then subjected to a post cure period after molding of the outer cover layer by heating at 130° F. for 30 mins and a subsequent and additional post cure for 24 hr at 100° F.

Example 8

The golf ball of Example 4 was then subjected to a post cure period after molding of the outer cover layer by heating at 130° F. for 30 mins and a subsequent and additional post cure for 24 hr at 100° F.

TABLE 2
Evaluation of Adhesion Between Vestenamer-based Mantle
with Ionomer Cover Using Epoxy Adhesion Promoting
Agent Under Different Heat Cure Conditions:
Epoxy White APCComp
Cure TreatmentExExExExExExExExEx
(conc/temp/time)112345678
No Epoxy APCX
100 mg/175° F./15 minXX
200 mg/175° F./15 minXX
100 mg/150° F./15 minXX
200 mg/150° F./15 minXX
100 mg/130° F./35 minX
200 mg/130° F./35 minX
100 mg/100° F./24 hrX
200 mg/100° F./24 hrX
Qualitative Adhesion133333333
Test Score

Analysis of the date in Table 2 demonstrate that the adhesion to an ionomer-based outer layer is improved when an epoxy-based APC is applied to a synthetic rubber polyalkenamer mantle with a wet weight of 100 mg, dried at 150° F. for 15 minutes, and then allowed to air dry until tackiness is removed. A higher concentration of APC on the ball or more rigorous curing conditions in terms of higher temperature and additional time maintain but do not further improve the observed additional adhesion improvement.

Comparative Example 2 and Examples 9-14

Comparative Example 2

A golf ball was prepared by first forming a unitary solid core made from a standard process that includes mixing the polybutadiene core material with a peroxide/zinc diacrylate-based crosslinking package in a two roll mill, extruding the mixture, and then forming and curing the core under heat and pressure in a compression molding cycle to yield a core having a diameter of 1.48 in. a specific gravity of 1.19 and a PGA compression of 45. A series of layers were injected around the core formed from a mixture of Vestenamer 8012 polyoctenamer, zinc oxide, SR638 zinc diacrylate, terachlorothiopyridine and Varox 231L peroxide, and polyaramid fiber sand the samples subjected to grinding on a Glebar precision grinder to yield a spherical core/mantle precursor having a diameter of 1.6 inches. An outer layer prepared from a polyurethane composition comprising a prepolymer formed from toluene diisocyanate and polytetramethylene ether glycol (PTMEG) and a curing agent comprising diethyl toluene diamine) was then cast around the spherical core/mantle precursor at a thickness of 0.04 in to yield a golf ball having a final diameter of 1.68 in. After allowing to age at room temperature for two weeks, the resulting ball was subjected to the Qualitative and Quantitative Adhesion Tests, the results of which are summarized in Table 3 below.

Example 9

A golf ball was prepared by first forming a unitary solid core made from a standard process that includes mixing the polybutadiene core material with a peroxide/zinc diacrylate-based crosslinking package in a two roll mill, extruding the mixture, and then forming and curing the core under heat and pressure in a compression molding cycle to yield a core having a diameter of 1.48 in, a specific gravity of 1.19 and a PGA compression of 45. A series of layers were injected around the core formed from a mixture of Vestenamer 8012 polyoctenamer, zinc oxide, SR638 zinc diacrylate, terachlorothiopyridine and Varox 231L peroxide, and polyaramid fibers to yield a spherical core/mantle precursor having a diameter of 1.6 inches. Acrylic modified urethane Cho-Kwang W-Primer (U) water-based APC was first diluted with water to yield a final Zahn cup viscosity of 14 secs. This solution was then mixed with CX-100 water based aziridine cross linker at a ratio of 6:1 part by weight of polyurethane to aziridine which solution was then loaded in the paint gun sprayer reservoir and the ball sprayed for sufficient time and in sufficient amount to result in the sample having a wet weight of 100 mg after application of the APC mixture. The sample was then dried at dried at 140° F. for 15 minutes, and then allowed to air dry until tackiness is removed. An outer layer prepared from a polyurethane composition comprising a prepolymer formed from toluene diisocyanate and polytetramethylene ether glycol (PTMEG) and a curing agent comprising diethyl toluene diamine was then cast around the spherical core/mantle precursor at a thickness of 0.04 in to yield a golf ball having a final diameter of 1.68 in. After allowing to age at room temperature for two weeks, the resulting ball was subjected to the Qualitative and Quantitative Adhesion Tests, the results are summarized in Table 3 below.

Example 10

A golf ball was prepared as for Example 9 except that Epoxy White APC was used after first diluting with ethyl acetate to arrive at a Than cup viscosity of 14 seconds and this solution was then loaded into the paint sprayer reservoir and the ball sprayed for sufficient time and in sufficient amount to result in the sample having a wet weight of 100 mg after application of the APC mixture. The sample was initially dried for 15 minutes at 175° F. and then air-dried until the tackiness of the epoxy was removed (approx. 4 hours at room temp). After application of the outer layer the ball was allowed to age at room temperature for two weeks, and was then subjected to the Qualitative and Quantitative Adhesion Tests, the results of which are summarized in Table 3 below.

Example 11

A golf ball was prepared as for Example 9 except that for the APC coat, a paint booth sprayer was used to apply Impranil DLP-R aliphatic polyurethane resin as an aqueous dispersion having a Than cup viscosity of 14 seconds and in sufficient amount to result in the sample having a wet weight of 100 mg after application of the APC mixture. The sample was initially dried for 10 minutes at 90° F. and then air-dried until the tackiness of the epoxy was removed (approx. 4 hours at room temp). After application of the outer layer the ball was allowed to age at room temperature for two weeks, and was then subjected to the Qualitative and Quantitative Adhesion Tests, the results of which are summarized in Table 3 below.

Example 12

A golf ball was prepared as for Example 10 except that after preparation and drying of the first Epoxy White APC coat, a paint booth sprayer was used to apply a second APC coat of the acrylic modified urethane Cho-Kwang W-Primer (U) water-based APC as for Example 9. After application of the outer layer the ball was allowed to age at room temperature for two weeks, and was then subjected to the Qualitative and Quantitative Adhesion Tests, the results of which are summarized in Table 3 below.

Example 13

A golf ball was prepared as for Example 10 except that after preparation and drying of the first Epoxy White APC coat, a paint booth sprayer was used to apply a second primer coat of Impranil DLP-R aliphatic polyurethane resin as an aqueous dispersion as for Example 11. After application of the outer layer, the ball was allowed to age at room temperature for two weeks, and was then subjected to both the Qualitative and Quantitative Adhesion Tests, the results of which are summarized in Table 3 below.

TABLE 3
Evaluation of Adhesion Between Polyalkenamer
Mantle with a Polyurethane Cover
APC Cure TreatmentComp
(conc/temp/time)Ex 2Ex 9Ex 10Ex 11Ex 12Ex 13
No primerX
1st Adhesion Promoter Coat
Cho-Kwang W UX
100 mg/140° F./15 min
Epoxy WhiteXXX
100 mg/175° F./15 min
Impranil DLP-RX
100 mg/90° F./10 min
2nd Adhesion Promoter Coat
Cho-Kwang W UX
100 mg/140° F./15 min
Impranil DLP-RX
100 mg/90° F./10 min
Qualitative Adhesion123133
Test Score
Quantitative3.18.018.4<317.530.6
Adhesion Test Max
Quantitative1.76.212.9<1.713.523.3
Adhesion Test Av.

Analysis of the data in Table 3 again demonstrates that when a single APC is used an epoxy-based system yields the best adhesion between a synthetic rubber-based layer and a thermoset polyurethane layer. Surprisingly, it was also determined that after application of an initial epoxy based APC, subsequent application of less effective APC's when used alone produce excellent adhesion when used in combination with an initial epoxy-based APC treatment. The scope of this synergistic effect can be better determined by analysis of the Quantitative Adhesion Test data which further define the scope of this synergism in the case of the combination of the epoxy-based APC followed by the aliphatic polyurethane-based Impranil APC. This effect is clearly more than additive, as the epoxy treatment alone, (Ex 10) yields adhesion test nos. of 18.4 N (max) and 12.9 (av) and the Impranil alone yields adhesion test nos. of <3 N (max) and <1.7 N (av), whereas the combination of the two APC's (Ex 13) yields adhesion test nos. of 30.6 N (max) and 23.3 (av).