Title:
Visual Effect on a Golf Ball Utilizing Overlapping Stamps on Different Layers
Kind Code:
A1


Abstract:
A golf ball with overlapping indicia is disclosed herein. The golf ball has a core and at least a cover layer. The cover layer of the golf ball is composed of a transparent, semi-transparent, translucent or semi-transluscent material. Each layer has an indicia thereon with the indicia on the non-cover layer visible.



Inventors:
Melanson, David M. (Northampton, MA, US)
Binette, Mark L. (Ludlow, MA, US)
Tzivanis, Michael J. (Chicopee, MA, US)
Miller, Scott R. (Southampton, MA, US)
Application Number:
11/459418
Publication Date:
02/01/2007
Filing Date:
07/24/2006
Primary Class:
Other Classes:
473/374, 473/378
International Classes:
A63B37/04; A63B37/06; A63B37/14
View Patent Images:
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Primary Examiner:
GORDEN, RAEANN
Attorney, Agent or Firm:
MICHAEL A. CATANIA (CARLSBAD, CA, US)
Claims:
We claim as our invention:

1. A golf ball comprising: an inner layer having a first indicia thereon; and a cover disposed over the inner layer, the cover composed of a translucent material and having a second indicia thereon; wherein the second indicia overlaps the first indicia.

2. The golf ball according to claim 1 wherein the inner layer is a core.

3. The golf ball according to claim 1 wherein the inner layer is an intermediate layer.

4. The golf ball according to claim 1 wherein the first indicia is larger in surface area than the second indicia.

5. A golf ball comprising: a core having a diameter ranging from 1.30 inches to 1.65 inches, the core having a surface; a first indicia disposed on the surface of the core; a cover disposed over the core and the first indicia, the cover composed of a translucent material or semi-translucent material, the cover having a thickness ranging from 0.01 inch to 1.0 inch, the cover having a surface; a second indicia disposed on the surface of the cover, the second indicia partially overlapping the first indicia.

6. The golf ball according to claim 5 further comprising a coating layer disposed over the second indicia.

7. The golf ball according to claim 6 further comprising a second coating layer disposed over the first coating layer.

8. The golf ball according to claim 5 wherein the cover is composed of an ionomer material.

9. The golf ball according to claim 5 wherein the first indicia is a different color from the second indicia.

10. A golf ball comprising: a core having a diameter ranging from 1.30 inches to 1.65 inches; an intermediate layer disposed over the core, the intermediate layer having a thickness ranging from 0.01 inch to 0.100 inch, the intermediate layer having a surface; a first indicia disposed on the surface of the intermediate layer; a cover disposed over the intermediate layer and the first indicia, the cover composed of a translucent material or semi-translucent material, the cover having a thickness ranging from 0.001 inch to 1.0 inch, the cover having a surface; and a second indicia partially overlapping the first indicia.

11. The golf ball according to claim 10 wherein the second indicia is disposed on the surface of the cover.

12. The golf ball according to claim 10 further comprising a coating layer, the second indicia disposed on the coating layer.

13. The golf ball according to claim 12 further comprising a second coating layer, the second coating layer disposed on the second indicia and the coating layer.

14. The golf ball according to claim 10 wherein the intermediate layer is composed of an inomer material.

15. The golf ball according to claim 10 wherein the cover is composed of a polyurethane material.

16. The golf ball according to claim 10 wherein the core is a liquid filled core.

Description:

CROSS REFERENCES

The Present Application claim priority to U.S. Provisional Application No. 60/595,676, filed on Jul. 27, 2005.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a golf ball. More specifically, the present invention relates to indicia utilized on a golf ball.

2. Description of the Related Art

Golf balls have been branded with logos and other symbols for many years. Typically, the indicia is placed on the outer surface of the golf ball and protected by a coating layer. This only provides a two dimensional effect on the golf ball.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a golf ball with a unique visual effect.

One aspect of the present invention is a golf ball with at least two layers. The cover layer is composed of a transparent, semi-transparent, translucent or semi-transluscent material. Each layer has an indicia thereon with the indicia on the non-cover layer visible.

Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of a golf ball with indicia thereon.

FIG. 2 is an isolated cross-sectional view of a two-piece golf ball with a single coating layer.

FIG. 3 is an isolated cross-sectional view of a two-piece golf ball with a two coating layers.

FIG. 4 is an isolated cross-sectional view of a three-piece golf ball with a single coating layer.

FIG. 5 is an isolated cross-sectional view of a three-piece golf ball with a single coating layer with a first indicia on an intermediate layer and a second indicia on a cover.

FIG. 6 is an isolated cross-sectional view of a three-piece golf ball with a single coating layer with a first indicia on an intermediate layer and a second indicia on a coating layer.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a golf ball is generally designated 10. The golf ball may be a two piece golf ball, three piece golf ball or multiple (greater than three) piece golf ball. The golf ball 10 has a second indicia 12 partially overlapping a first indicia 1 4.

As shown in FIG. 2, the golf ball 10 has a core 20 and a cover 22. The core 20 has a surface 21 with the first indicia 14 thereon. The cover 22 is disposed over the core 20 and the first indicia 14. The cover is composed of a transparent material or a semi-translucent material. The second indicia 12 is disposed a surface 23 of the cover 22. The second indicia 12 partially overlaps the first indicia 14. A coating layer 30 is disposed on the cover 22 and the second indicia 12.

As shown in FIG. 3, the golf ball 10 has a core 20 and a cover 22. The core 20 has a surface 21 with the first indicia 14 thereon. The cover 22 is disposed over the core 20 and the first indicia 14. The cover is composed of a transparent material or a semi-translucent material. A first coating layer 30 is disposed over the cover 22. The second indicia 12 is disposed a surface 31 of the first coating layer 30. The second indicia 12 partially overlaps the first indicia 14. A second coating layer 32 is disposed on the first coating layer 30 and the second indicia 12.

As shown in FIG. 4, the golf ball 10 has a core 20, an intermediate layer 24 and a cover 22. The core 20 has a surface 21 with the first indicia 14 thereon. The intermediate layer 24 is disposed over the core and the first indicia 14. The cover 22 is disposed over the intermediate layer 24. The cover 22 and the intermediate layer are each composed of a transparent, semi-translucent or transluscent material. The second indicia 12 is disposed a surface 23 of the cover 22. The second indicia 12 partially overlaps the first indicia 14. A coating layer 30 is disposed on the cover 22 and the second indicia 12.

As shown in FIG. 5, the golf ball 10 has a core 20, an intermediate layer 24 and a cover 22. The intermediate layer 24 is disposed over the core 20. The intermediate layer 24 has a surface 25 with the first indicia 14 thereon. The cover 22 is disposed over the intermediate layer 24 and the first indicia 14. The cover 22 is composed of a translucent material or a semi-translucent material. A first coating layer 30 is disposed over the cover 22. The second indicia 12 is disposed a surface 31 of the first coating layer 30. The second indicia 12 partially overlaps the first indicia 14.

As shown in FIG. 6, the golf ball 10 has a core 20, an intermediate layer 24 and a cover 22. The intermediate layer 24 is disposed over the core 20. The intermediate layer 24 has a surface 25 with the first indicia 14 thereon. The cover 22 is disposed over the intermediate layer 24 and the first indicia 14. The cover 22 is composed of a transparent material or a semi-translucent material. The second indicia 12 is disposed a surface 23 of the cover 22. The second indicia 12 partially overlaps the first indicia 14. A coating layer 30 is disposed on the cover 22 and the second indicia 12.

Preferably, the first indicia 14 covers a greater surface area than the second indicia 12. In a preferred embodiment, the first indicia 14 is a different color than the second indicia 12.

In a preferred embodiment, the cover is a multi-layer cover comprising an inner cover layer or layers formed over the core. Preferably, the inner cover layer is harder than the outer cover layer, the inner cover layer having a Shore D hardness of at least 60 (or at least about 80 Shore C) as measured on the surface thereof, and a softer outer cover layer comprising thermoplastic or thermoset polyurethane, polyurea or polyurethane/polyurea formed over the inner cover layer, the outer cover layer having a Shore B hardness of less than 98, preferably a Shore B hardness of 95 or less, more preferably 90 or less, as measured on the surface thereof, the golf ball cover having improved scuff resistance. Furthermore, the golf ball cover may be formed using a reaction injection molding process.

In another aspect, the present invention provides a golf ball comprising a core, a hard inner cover layer formed over the core, and a softer outer cover layer formed over the inner cover layer. The inner cover layer has a Shore D hardness of at least 60 (or at least about 80 Shore C) as measured on the curved surface thereof and is formed of a composition including at least one material selected from the group of consisting of ionomers, polyamides, polyurethanes, polyureas, polyester elastomers, polyester amides, metallocene catalyzed polyolefins, and blends thereof. The outer cover layer has a Shore B hardness of less than 98, preferably a Shore B hardness of 95 or less, more preferably 90 or less, as measured on the curved surface thereof. It is formed from a composition comprising a polyurethane, polyurea or polyurethane/polyurea material, with said composition being formed via injection molding or reaction injection molding.

The golf ball precursor products utilized with the invention can be of a standard or enlarged size. The core may have multiple layers, such as a dual core having a spherical center or inner core and a core layer surrounding the inner core. Additional core layers may also be present. The cover layer is preferably a multi-layer cover comprising at least an inner cover layer and an outer cover, although any number of cover layers, such as 2, 3, 4, 5 or more is possible.

The core or the dual core of the golf ball precursor product can be formed of a solid, a liquid, or any other substance that will result in an inner ball (core and inner cover layer), having the desired COR, compression and hardness. The multi-layered cover preferably comprises two layers: a first or inner layer or ply and a second or outer layer or ply. The inner layer can be ionomer, ionomer blends, non-ionomer, non-ionomer blends, or blends of ionomer and non-ionomer. The outer layer is preferably softer than the inner layer and can be thermoplastic or thermoset polyurethane, polyurea, polyurethane/polyurea blends, or a blend of a polyurethane/polyurea and ionomer or non-ionomer. The cover is preferably formed using injection molding or reaction injection molding techniques.

In a further embodiment, the inner layer is comprised of a hard, high acid (i.e. greater than 16 weight percent acid) ionomer resin or high acid ionomer blend. Preferably, the inner layer is comprised of a blend of two or more high acid (i.e. at least 16 weight percent acid) ionomer resins neutralized to various extents by different metal cations. The inner cover layer may or may not include a metal stearate (e.g., zinc stearate) or other metal fatty acid salt. The purpose of the metal stearate or other metal fatty acid salt is to lower the cost of production without affecting the overall performance of the finished golf ball. In an additional embodiment, the inner layer is comprised of a hard, low acid (i.e. 16 weight percent acid or less) ionomer blend. Preferably, the inner layer is comprised of a blend of two or more low acid (i.e. 16 weight percent acid or less) ionomer resins neutralized to various extents by different metal cations. The inner cover layer may or may not include a metal stearate (e.g., zinc stearate) or other metal fatty acid salt. In an additional embodiment the inner layer is comprised of a highly neutralized ionomeric material modifies with fatty acids or fatty acids salts.

In another preferred embodiment, the cover is a multi-layer cover comprising an inner cover layer over a core. The inner layer is softer than the outer layer, with the inner cover layer having a Shore D hardness of 60 or less as measured on the surface and the outer cover having a Shore D hardness of 61 or more. The inner cover layer is preferably a soft or low acid ionomer ionomer. Furthermore, this inner layer may consist of a highly neutralized ionomer modified with a fatty acid salt (e.g. magnesium oleate, magnesium stearate, etc.) The inner cover layer may also contain other fillers such as colorants, optical brighteners, and heavy metal fillers. The outer cover is preferably a medium to high acid ionomer of low haze and high clarity.

It has been found that a hard inner layer provides for a substantial increase in resilience (i.e., enhanced distance) over known multi-layer covered balls. The softer outer layer provides for desirable “feel” and high spin rate while maintaining respectable resiliency. The soft outer layer allows the cover to deform more during impact and increases the area of contact between the clubface and the cover, thereby imparting more spin on the ball. As a result, the soft cover provides the ball with a balata-like feel and playability characteristics with improved distance and durability. Consequently, the overall combination of the inner and outer cover layers results in a golf ball having enhanced resilience (improved travel distance) and durability (i.e. cut resistance, etc.) characteristics while maintaining and in many instances, improving, the playability properties of the ball.

The combination of a hard inner cover layer or layers with a soft, relatively low modulus thermoplastic or thermoset polyurethane, polyurea or polyurethane/polyurea outer cover layer provides for excellent overall coefficient of restitution (for example, excellent resilience) because of the improved resiliency produced by the inner cover layer. While some improvement in resiliency is also produced by the outer cover layer, the outer cover layer generally provides for a more desirable feel and high spin, particularly at lower swing speeds with highly lofted clubs such as half wedge shots.

Preferably, the inner cover layer is harder than the outer cover layer and generally has a thickness of 0.010 to 0.150 inches, preferably 0.010 to 0.100 inches for a 1.72 inch (or more) ball. The core and inner cover layer together form an inner ball having a coefficient of restitution of 0.750 or more and more preferably 0.790 or more, and a diameter in the range of 1.48 to 1.67 inches for a 1.68 inch ball and 1.50 to 1.71 inches for a 1.72 inch (or more) ball. The inner cover layer has a Shore D hardness of 50 or more (or at least about 70 Shore C). It is particularly advantageous if the golf balls of the invention have an inner layer with a Shore D hardness of 65 or more (or at least about 94 Shore C). If the inner layer is too thin, it is very difficult to accurately measure the Shore D, and sometimes the Shore C, of the inner layer as the layer may puncture. Additionally, if the core is harder, this will sometimes influence the reading. If the Shore C or Shore D is measured on a plaque of material, different values will result. The above-described characteristics of the inner cover layer provide an inner ball having a PGA compression of 100 or less. It is found that when the inner ball has a PGA compression of 90 or less, excellent playability results.

The inner layer compositions of the embodiments described herein may include the high acid ionomers such as those developed by E.I. DuPont de Nemours & Company under the trademark Surlyn® and by Exxon Corporation under the trademarks Escor® or Iotek®, or blends thereof.

The high acid ionomers which may be suitable for use in formulating the inner layer compositions of various embodiments of the invention are ionic copolymers which are the metal, (such as sodium, zinc, magnesium, etc.), salts of the reaction product of an olefin having from about 2 to 8 carbon atoms and an unsaturated monocarboxylic acid having from about 3 to 8 carbon atoms. Preferably, the ionomeric resins are copolymers of ethylene and either acrylic or methacrylic acid. In some circumstances, an additional comonomer such as an acrylate ester (for example, iso- or n-butylacrylate, etc.) can also be included to produce a softer terpolymer.

The carboxylic acid groups of the copolymer are partially neutralized (for example, approximately 10-100%, preferably 30-70%) by the metal ions. Each of the high acid ionomer resins which may be included in the inner layer cover compositions of the invention contains greater than about 16% by weight of a carboxylic acid, preferably from about 17% to about 25% by weight of a carboxylic acid, more preferably from about 18.5% to about 21.5% by weight of a carboxylic acid.

The high acid ionomeric resins available from Exxon under the designation Escor® or Iotek®, are somewhat similar to the high acid ionomeric resins available under the Surlyn® trademark. However, since the Escor®/Iotek® ionomeric resins are sodium or zinc salts of poly(ethylene-acrylic acid) and the Surlyn® resins are zinc, sodium, magnesium, etc. salts of poly(ethylene-methacrylic acid), distinct differences in properties exist.

Examples of the high acid methacrylic acid based ionomers found suitable for use in accordance with this invention include Surlyn® 8220 and 8240 (both formerly known as forms of Surlyn® AD-8422), Surlyn® 9220 (zinc cation), Surlyn® SEP-503-1 (zinc cation), and Surlyn® SEP-503-2 (magnesium cation). According to DuPont, all of these ionomers contain from about 18.5 to about 21.5% by weight methacrylic acid.

Examples of the high acid acrylic acid based ionomers suitable for use in the present invention also include the Escor® or Iotek® high acid ethylene acrylic acid ionomers produced by Exxon such as Ex 1001, 1002, 959, 960, 989, 990, 1003, 1004, 993, 994. In this regard, Escor® or Iotek® 959 is a sodium ion neutralized 20 ethylene-acrylic neutralized ethylene-acrylic acid copolymer. According to Exxon, Ioteks® 959 and 960 contain from about 19.0 to about 21.0% by weight acrylic acid with approximately 30 to about 70 percent of the acid groups neutralized with sodium and zinc ions, respectively.

Furthermore, as a result of the development by the assignee of this application of a number of high acid ionomers neutralized to various extents by several different types of metal cations, such as by manganese, lithium, potassium, calcium and nickel cations, several high acid ionomers and/or high acid ionomer blends besides sodium, zinc and magnesium high acid ionomers or ionomer blends are now available for golf ball cover production. It has been found that these additional cation neutralized high acid ionomer blends produce inner cover layer compositions exhibiting enhanced hardness and resilience due to synergies that occur during processing. Consequently, the metal cation neutralized high acid ionomer resins recently produced can be blended to produce substantially higher C.O.R.'s than those produced by the low acid ionomer inner cover compositions presently commercially available.

More particularly, several metal cation neutralized high acid ionomer resins have been produced by the assignee of this invention by neutralizing, to various extents, high acid copolymers of an alpha-olefin and an alpha, beta-unsaturated carboxylic acid with a wide variety of different metal cation salts. This discovery is the subject matter of U.S. Pat. No. 5,688,869, incorporated herein by reference. It has been found that numerous metal cation neutralized high acid ionomer resins can be obtained by reacting a high acid copolymer (i.e. a copolymer containing greater than 16% by weight acid, preferably from about 17 to about 25 weight percent acid, and more preferably about 20 weight percent acid), with a metal cation salt capable of ionizing or neutralizing the copolymer to the extent desired (for example, from about 10% to 90%).

The base copolymer is made up of greater than 16% by weight of an alpha, beta-unsaturated carboxylic acid and an alpha-olefin. Optionally, a softening comonomer can be included in the copolymer. Generally, the alpha-olefin has from 2 to 10 carbon atoms and is preferably ethylene, and the unsaturated carboxylic acid is a carboxylic acid having from about 3 to 8 carbons. Examples of such acids include acrylic acid, methacrylic acid, ethacrylic acid, chloroacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid, with acrylic acid being preferred.

The softening comonomer that can be optionally included in the inner cover layer for the golf ball of the invention may be selected from the group consisting of vinyl esters of aliphatic carboxylic acids wherein the acids have 2 to 10 carbon atoms, vinyl ethers wherein the alkyl groups contains 1 to 10 carbon atoms, and alkyl acrylates or methacrylates wherein the alkyl group contains 1 to 10 carbon atoms. Suitable softening comonomers include vinyl acetate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, or the like.

Consequently, examples of a number of copolymers suitable for use to produce the high acid ionomers included in the present invention include, but are not limited to, high acid embodiments of an ethylene/acrylic acid copolymer, an ethylene/methacrylic acid copolymer, an ethylene/itaconic acid copolymer, an ethylene/maleic acid copolymer, an ethylene/methacrylic acid/vinyl acetate copolymer, an ethylene/acrylic acid/vinyl alcohol copolymer, etc. The base copolymer broadly contains greater than 16% by weight unsaturated carboxylic acid, from about 39 to about 83% by weight ethylene and from 0 to about 40% by weight of a softening comonomer. Preferably, the copolymer contains about 20% by weight unsaturated carboxylic acid and about 80% by weight ethylene. Most preferably, the copolymer contains about 20% acrylic acid with the remainder being ethylene.

Along these lines, examples of the preferred high acid base copolymers which fulfill the criteria set forth above, are a series of ethylene-acrylic copolymers which are commercially available from The Dow Chemical Company, Midland, Mich., under the Primacor® designation.

The metal cation salts utilized in the invention are those salts that provide the metal cations capable of neutralizing, to various extents, the carboxylic acid groups of the high acid copolymer. These include acetate, oxide or hydroxide salts of lithium, calcium, zinc, sodium, potassium, nickel, magnesium, and manganese.

Examples of such lithium ion sources are lithium hydroxide monohydrate, lithium hydroxide, lithium oxide and lithium acetate. Sources for the calcium ion include calcium hydroxide, calcium acetate and calcium oxide. Suitable zinc ion sources are zinc acetate dihydrate and zinc acetate, a blend of zinc oxide and acetic acid. Examples of sodium ion sources are sodium hydroxide and sodium acetate. Sources for the potassium ion include potassium hydroxide and potassium acetate. Suitable nickel ion sources are nickel acetate, nickel oxide and nickel hydroxide. Sources of magnesium include magnesium oxide, magnesium hydroxide, and magnesium acetate. Sources of manganese include manganese acetate and manganese oxide.

The metal cation neutralized high acid ionomer resins are produced by reacting the high acid base copolymer with various amounts of the metal cation salts above the crystalline melting point of the copolymer, such as at a temperature from about 200° F. to about 500° F., preferably from about 250° F. to about 350° F. under high shear conditions at a pressure of from about 10 psi to 10,000 psi. Other well known blending techniques may also be used. The amount of metal cation salt utilized to produce the new metal cation neutralized high acid based ionomer resins is the quantity which provides a sufficient amount of the metal cations to neutralize the desired percentage of the carboxylic acid groups in the high acid copolymer. The extent of neutralization is generally from about 10% to about 90%.

A number of different types of metal cation neutralized high acid ionomers can be obtained from the above-indicated process. These include high acid ionomer resins neutralized to various extents with manganese, lithium, potassium, calcium and nickel cations. In addition, when a high acid ethylene/acrylic acid copolymer is utilized as the base copolymer component of the invention and this component is subsequently neutralized to various extents with the metal cation salts producing acrylic acid based high acid ionomer resins neutralized with cations such as sodium, potassium, lithium, zinc, magnesium, manganese, calcium and nickel, several cation neutralized acrylic acid based high acid ionomer resins are produced.

When compared to low acid versions of similar cation neutralized ionomer resins, the new metal cation neutralized high acid ionomer resins exhibit enhanced hardness, modulus and resilience characteristics. These are properties that are particularly desirable in a number of thermoplastic fields, including the field of golf ball manufacturing.

When utilized in the construction of the inner layer of a multi-layered golf ball, it has been found that the acrylic acid based high acid ionomers extend the range of hardness beyond that previously obtainable while maintaining the beneficial properties (i.e. durability, click, feel, etc.) of the softer low acid ionomer covered balls, such as balls produced utilizing the low acid ionomers disclosed in U.S. Pat. Nos. 4,884,814 and 4,911,451. By using these high acid ionomer resins, harder, stiffer inner cover layers having higher C.O.R.s, and thus longer distance, can be obtained.

More preferably, it has been found that when two or more of the above-indicated high acid ionomers, particularly blends of sodium and zinc high acid ionomers, are processed to produce the covers of multi-layered golf balls, (for example, the inner cover layer or layers herein) the resulting golf balls will travel further than previously known multi-layered golf balls produced with low acid ionomer resin covers due to the balls' enhanced coefficient of restitution values.

Alternatively, if the inner cover layer comprises a low acid, the low acid ionomers which may be suitable for use in formulating the inner layer compositions of the subject invention are ionic copolymers which are the metal, (sodium, zinc, magnesium, etc.), salts of the reaction product of an olefin having from about 2 to 8 carbon atoms and an unsaturated monocarboxylic acid having from about 3 to 8 carbon atoms. Preferably, the ionomeric resins are copolymers of ethylene and either acrylic or methacrylic acid. In some circumstances, an additional comonomer such as an acrylate ester (for example, iso- or n-butylacrylate, etc.) can also be included to produce a softer terpolymer. The carboxylic acid groups of the copolymer are partially neutralized (for example, approximately 10 to 100%, preferably 30 to 70%) by the metal ions. Each of the low acid ionomer resins which may be included in the inner layer cover compositions of the invention contains 16% by weight or less of a carboxylic acid.

The inner layer compositions include the low acid ionomers such as those developed and sold by E.I. DuPont de Nemours & Company under the trademark Surlyn® and by Exxon Corporation under the trademarks Escor® or Iotek®, or blends thereof.

The low acid ionomer resins available from Exxon under the designation Escor” and/or Iotek®, are somewhat similar to the low acid ionomeric resins available under the Surlyn® trademark. However, since the Escor®/Iotek® ionomeric resins are sodium or zinc salts of poly(ethylene-acrylic acid) and the Surlyn® resins are zinc, sodium, magnesium, etc. salts of poly(ethylene-methacrylic acid), distinct differences in properties exist.

When utilized in the construction of the inner layer of a multi-layered golf ball, it has been found that the low acid ionomer blends extend the range of compression and spin rates beyond that previously obtainable. More preferably, it has been found that when two or more low acid ionomers, particularly blends of sodium and zinc ionomers, are processed to produce the covers of multi-layered golf balls, (for example, the inner cover layer herein) the resulting golf balls will travel further and at an enhanced spin rate than previously known multi-layered golf balls. Such an improvement is particularly noticeable in enlarged or oversized golf balls.

In one embodiment of the inner cover layer, a blend of high and low acid ionomer resins is used. These can be the ionomer resins described above, combined in a weight ratio which preferably is within the range of 10 to 90 to 90 to 10 high and low acid ionomer resins.

Another embodiment of the inner cover layer is primarily or fully non-ionomeric thermoplastic material. Suitable non-ionomeric materials include metallocene catalyzed polyolefins or polyamides, polyamide/ionomer blends, polyphenylene ether/ionomer blends, etc., which have a Shore D hardness of at least 60 (or at least about 80 Shore C) and a flex modulus of greater than about 15,000, more preferably about 30,000 psi, or other hardness and flex modulus values which are comparable to the properties of the ionomers described above. Other suitable materials include but are not limited to thermoplastic or thermosetting polyurethanes, thermoplastic block polyesters, for example, a polyester elastomer such as that marketed by DuPont under the trademark Hytrel®, or thermoplastic block polyamides, for example, a polyether amide such as that marketed by Elf Atochem S. A. under the trademark Pebax®, a blend of two or more non-ionomeric thermoplastic elastomers, or a blend of one or more ionomers and one or more non-ionomeric thermoplastic elastomers. These materials can be blended with the ionomers described above in order to reduce cost relative to the use of higher quantities of ionomer.

A golf ball inner cover layer according to the present invention formed from a polyurethane material typically contains from about 0 to about 60 weight percent of filler material, more preferably from about 0 to about 30 weight percent, and most preferably from about 0 to about 20 weight percent.

While the core with the hard inner cover layer formed thereon provides the multi-layer golf ball with power and distance, the outer cover layer is preferably comparatively softer than the inner cover layer. The softness provides for the feel and playability characteristics typically associated with balata or balata-blend balls. The outer cover layer or ply is comprised of a relatively soft, low modulus (about 1,000 psi to about 100,000 psi, preferably about 5,000 psi to about 70,000) thermoplastic or thermoset polyurethane, polyurea or polyurethane/polyurea, or a blend of two or more polyurethanes, or a blend of one or more ionomers or one or more non-ionomeric thermoplastic materials with a thermoplastic polyurethane. The outer layer is 0.005 to about 0.150 inch in thickness, preferably 0.010 to 0.075 inch in thickness, more desirably 0.015 to 0.040 inch in thickness, but thick enough to achieve desired playability characteristics while minimizing expense. Thickness is defined as the average thickness of the non-dimpled areas of the outer cover layer. The outer cover layer preferably has a Shore C hardness of less than 98, preferably 95 or less, and more preferably 90 or less, as measured on the surface of the golf ball. If the inner layer and/or core are harder than the outer layer, this will sometimes influence the reading. If the Shore C is measured on a plaque of material, different values may result.

The outer cover layer of the invention is formed over a core to result in a golf ball having a coefficient of restitution of at least 0.750, more preferably at least 0.780, and most preferably at least 0.790. The coefficient of restitution of the ball will depend upon the properties of both the core and the cover. The PGA compression of the golf ball is 100 or less, and preferably is 90 or less.

In polyurethanes, cross-linking occurs between the isocyanate groups (—NCO) and the polyol's hydroxyl end-groups (—OH), and/or with already formed urethane groups. Additionally, the end-use characteristics of polyurethanes can also be controlled by different types of reactive chemicals and processing parameters. For example, catalysts are utilized to control polymerization rates.

Generally, thermoplastic polyurethanes have some cross-linking, but primarily by physical means. The cross-link bonds can be reversibly broken by increasing temperature, as occurs during molding or extrusion. In this regard, thermoplastic polyurethanes can be injection molded, and extruded as sheet and blow film. They can be used up to about 350° F. to 450° F. and are available in a wide range of hardnesses.

The thermoplastic polyurethane, polyurea or polyurethane/polyurea which is selected for use as a golf ball cover preferably has a Shore C hardness of from about 98 or less, more preferably about 95 or less, and most preferably about 90 or less when measured on the surface of the golf ball. The thermoplastic polyurethane, polyurea or polyurethane/polyurea which is to be used for a cover layer preferably has a flex modulus from about 1 to about 310 Kpsi, more preferably from about 5 to about 100 Kpsi, and most preferably from about 5 to about 70 Kpsi. Accordingly, covers comprising these materials exhibit similar properties.

Moreover, in alternative embodiments, either the inner and/or the outer cover layer may also additionally comprise up to 100 wt % of a soft, low modulus, non-ionomeric thermoplastic or thermoset material. Non-ionomeric materials are suitable so long as they produce the playability and durability characteristics desired without adversely affecting the enhanced travel distance characteristic produced by the high acid ionomer resin composition. These include but are not limited to styrene-butadiene-styrene block copolymers, including functionalized styrene-butadiene-styrene block copolymers, styrene-ethylene-butadiene-styrene (SEBS) block copolymers such as Kraton® materials from Shell Chem. Co., and functionalized SEBS block copolymers; metallocene catalyzed polyolefins; ionomer/rubber blends such as those in Spalding U.S. Pat. Nos. 4,986,545; 5,098,105 and 5,187,013; silicones; and Hytrel® polyester elastomers from DuPont and Pebax® polyetheramides from Elf Atochem S. A. A preferred non-ionomeric material suitable for the inner and/or outer cover layer includes polyurethane.

Additional materials may also be added to the inner and outer cover layer of the present invention as long as they do not substantially reduce the playability properties of the ball. Such materials include dyes (for example, Ultramarine Blue™ sold by Whittaker, Clark, and Daniels of South Plainsfield, N.J.) (see U.S. Pat. No. 4,679,795); pigments such as titanium dioxide, zinc oxide, barium sulfate and zinc sulfate; UV absorbers; antioxidants; antistatic agents; and stabilizers. Moreover, the cover compositions of the present invention may also contain softening agents such as those disclosed in U.S. Pat. Nos. 5,312,857 and 5,306,760, including plasticizers, metal stearates and other type of metallic fatty acids, processing acids, etc., and reinforcing materials such as glass fibers and inorganic fillers, as long as the desired properties produced by the golf ball covers of the invention are not impaired.

From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.





 
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