DETAILED DESCRIPTION OF THE INVENTION

[0058] The present invention is directed to compositions including oxa acids and/or oxa acids salts combined with an non-neutralized or partially neutralized polymers to produce highly neutralized polymers for use in golf ball components. The present invention also relates to golf balls including at least one foamed or unfoamed layer that includes at least one oxa ester, at least one saponified polymer, saponified polymer/oxa ester blends, oxa acids, oxa acid/oxa ester blends, all of which may be blended with conventional ionomers and thermoplastic ionomers, grafted metallocene catalyzed polymers or polymer blends, non-grafted metallocene catalyzed polymers or polymer blends, as well as additives well known in the golf ball art. The compositions of the invention are contemplated for use in golf balls of any construction, e.g., one-piece, two-piece, and three-piece balls.

[0059] As used herein, the terms “conventional ionomers” and “conventional thermoplastic ionomers”, refer to copolymers and terpolymers including an a-olefin, an α,β-unsaturated carboxylic acid, and, optionally, a softening monomer, such as an acrylate class ester, where at least a portion the carboxylic acid groups on the polymer have been neutralized with at least one metal atom, such as lithium, sodium, potassium, cesium, magnesium, calcium, barium, zinc, manganese, copper, and aluminum. In addition, as used herein, the term “metallocene catalyzed polymer” refers to any polymer, copolymer, or terpolymer, and, in particular, any polyolefin, polymerized using a metallocene catalyst. The term “grafted metallocene catalyzed polymer” refers to any metallocene catalyzed polymer in which the metallocene catalyzed polymer has been subjected to a post-polymerization reaction to graft at least one functional group onto the metallocene catalyzed polymer. Similarly, the term “non-grafted metallocene catalyzed polymer” refers to any metallocene catalyzed polymer in which the metallocene catalyzed polymer has not been subjected to such a post-polymerization reaction. Accordingly, the term “metallocene catalyzed polymer” encompasses both non-grafted metallocene catalyzed polymers and grafted metallocene catalyzed polymers.

[0060] Compositions of the Invention

[0061] As briefly discussed above, the compositions of the present invention may include saponified polymers, oxa esters, oxa acids, highly neutralized polymers, and blends thereof. For example, in one embodiment, an oxa acid and/or a salt thereof is combined with a thermoplastic resin component having an acid or ionic group, i.e., an acid polymer or partially neutralized polymer, to produce a highly neutralized polymer. As used herein, a partially neutralized polymer should be understood to mean polymers with about 10 to about 70 percent of the acid groups neutralized. In another aspect of the invention, the compositions of the invention include an oxa ester/saponified polymer blend. The compositions of the invention, components of the compositions, ball construction, and ball properties are discussed in detail below.

[0062] Highly Neutralized Polymers

[0063] Unlike methods using fatty acid moieties to produce highly neutralized polymers, the present invention employs a novel combination of an oxa acid and/or a salts thereof, a thermoplastic resin component, and an inorganic metal compound or organic amine compound to produce highly neutralized polymers. In this aspect of the invention, the oxa acid acts as a reactive processing aid to avoid processing problems typically encountered with other methods of making highly neutralized polymers. As used herein, the term highly neutralized polymer is intended to cover those polymers having greater than about 70 percent of the acid groups neutralized. In one embodiment, about 80 percent or greater of the acid groups are neutralized. In another embodiment, about 90 percent or greater of the acid groups are neutralized. In still another embodiment, all of the acid groups (100 percent) in the polymer composition are neutralized.

[0064] Thus, highly neutralized polymers according to the invention may be formed from a composition including at least one oxa acid, oxa acid salt, or oxa ester and at least one thermoplastic resin component having an acid or ionic group. In one embodiment, about 0.1 percent to about 50 percent by weight of at least one oxa acid, oxa salt, oxa ester, or combination thereof, preferably about 1 percent to about 50 percent by weight of the composition, is combined with about 50 percent to about 99 percent by weight thermoplastic resin component to form a highly neutralized polymer composition. In addition, at least one inorganic metal compound or organic amine compound is preferably included in the composition. For example, about 0.5 percent to about 10 percent by weight inorganic metal compound or organic amine compound may be used in the compositions of the invention.

[0065] In another embodiment, a highly neutralized polymer composition according to the present invention includes about 5 percent to about 40 percent by weight of at least one oxa acid, oxa salt, or combination thereof, about 60 percent to about 95 percent by weight thermoplastic resin component to form a highly neutralized polymer composition. In addition, about 1 percent to about 8 percent by weight inorganic metal compound or organic amine compound may be used in the compositions of the invention. In still another embodiment, the highly neutralized polymer composition includes about 10 percent to about 30 percent by weight of at least one oxa acid, about 70 percent to about 90 percent by weight of at least one thermoplastic resin component, and about 2 percent to about 6 percent by weight of an inorganic metal compound, organic amine, or a combination thereof.

[0066] Oxa Acids and Salts Thereof

[0067] For the purposes of the present invention, any oxa acid that functions as a reactive processing moiety may be used in the compositions of the invention. In another embodiment, the oxa acid has the following formula: 8

[0068] wherein R is an organic moiety selected from the group consisting of moieties having the formula —[CH ₂ —CH ₂ O] _n —R′ and alkyl, carbocyclic, and heterocyclic groups, wherein R′ is an organic moiety selected from the group consisting of alkyl, carbocyclic, carboxylic acid, heterocyclic groups, and mixtures thereof, and wherein n is at least 1.

[0069] Numerous oxa acid compounds useful in the compositions of the present invention are available from Hoechst Celanese Corporation, Fine Chemicals Division under the trade name “Oxa Acids.” In particular, the oxa acid, oxa acid salt, or mixture thereof may include 3,6-dioxaheptanoic acid, 7,7-dimethyl-3,6-dioxaheptanoic acid, 3,6-dioxaheptanoic acid ethyl ester, 3,6-dioxaheptanoic acid dodecyl ester, 2-phenyl-3,6-dioxaheptanoic acid, 2-benzyl-3,6-dioxaheptanoic acid, 2-methyl-3,6- dioxaheptanoic acid, 3,6,9-trioxadecanoic acid, 3,6,9-trioxaheptanoic acid, 2-phenyl-3,6,9-trioxaheptanoic acid, 2-benzyl-3,6,9-trioxaheptanoic acid, 2-decyl-3,6,9-trioxaheptanoic acid, 3,6,9-trioxaundecanedioic acid, 3,6,9,12-tetraoxatridecanoic acid, 3,6,9,12,15-pentaoxahexadecanoic acid, 2-methyl-3,6,9-trioxadecanoic acid, 10,10-dimethyl-3,6,9-trioxadecanoic acid, 2-ethyl-3,6,9,12-tetraoxatridecanoic acid, 10-phenyl-3,6,9-trioxadecanoic acid, 3,6,9-trioxadecanoic acid ethyl ester, 10,10-dimethyl-3,6,9-trioxadecanoic acid ethyl ester, 10,10-dimethyl-3,6,9-trioxadecanoic acid heptadecanyl ester, polyglycol diacid, and mixtures thereof. In one embodiment, the oxa acid includes 3,6-dioxaheptanoic acid, 3,6,9 trioxadecanoic acid, 3,6,9-trioxaundecanedioic acid, polyglycol diacid (where n=about 10 to about 12), and mixtures thereof, which have the following formulae: 9

[0070] The oxa acid preferably has an acid number (calculated by dividing acid equivalent weight to 56,100) of at least about 10 mg KOH/g, preferably from about 20 mg KOH/g to about 420 mg KOH/g, more preferably from about 25 mg KOH/g to about 150 mg KOH/g, and most preferably from about 30 mg KOH/g to about 75 mg KOH/g. In one embodiment, the acid number of the oxa acid is about 50 mg KOH/g or greater.

[0071] The viscosity of the oxa acid is preferably about 35 mPAS at 20° C. In one embodiment, the viscosity is about 40 mPAS or greater. In another embodiment, the oxa acid has a viscosity of about 45 mPAS or greater.

[0072] The thermoplastic resin component may include any suitable olefin-unsaturated carboxylic acid random copolymer, any olefin-unsaturated carboxylic acid-unsaturated carboxylate ternary copolymer, any olefin-unsaturated carboxylic acid-unsaturated carboxylate ternary copolymer at least partially neutralized with a metal ion, and mixtures thereof. In one embodiment, the thermoplastic resin component for use in the present invention includes polyolefins, olefin elastomers, urethane elastomers, polyester elastomers, styrene elastomers, polyamide elastomers, polyurea elastomers, polyamides, polycarbonates, polyimides, polyacrylates, polysilicones, or mixtures thereof. Thus, the thermoplastic resin component of the invention preferably includes at least one acid group, ionic group, or combination thereof.

[0073] In one embodiment, the thermoplastic resin component is an ionic copolymer or terpolymer of ethylene based on an α,β-unsaturated carboxylic acid, such as acrylic acid or methacrylic acid. Ethylene methacrylic acid ionomers and ethylene acrylic acid ionomers and their terpolymers are sold commercially under the trade names SURLYN® and IOTEK® or ESCOR®, which are manufactured by DuPont and Exxon, respectively. These are copolymers or terpolymers of ethylene and methacrylic acid or acrylic acid at least partially neutralized to about 10 to about 70 percent with salts of zinc, sodium, lithium, magnesium, potassium, calcium, manganese, nickel or the like. The carboxylic acid groups may also include methacrylic, crotonic, maleic, fumaric or itaconic acid. The salts are the reaction product of an olefin having from 2 to 10 carbon atoms and an unsaturated monocarboxylic acid having 3 to 8 carbon atoms.

[0074] In one embodiment, the thermoplastic resin component includes at least one ionomer, such as acid-containing ethylene copolymer ionomers, including E/X/Y terpolymers where E is ethylene, X is an acrylate or methacrylate-based softening comonomer present in about 0 to 50 weight percent, and Y is acrylic or methacrylic acid present in about 5 to 35 weight percent. In another embodiment, the acrylic or methacrylic acid is present in about 5 to 30 weight percent, more preferably 8 to 25 weight percent, and most preferably 8 to 20 weight percent.

[0075] The thermoplastic resin component may also include so-called “low acid” and “high acid” ionomers, as well as blends thereof. In general, ionic copolymers including up to about 15 percent acid are considered “low acid” ionomers, while those including greater than about 15 percent acid are considered “high acid” ionomers.

[0076] Use of a low acid ionomeric composition in a golf ball is believed to impart high spin. Thus, in one embodiment, the thermoplastic resin includes a low acid ionomer where the acid is present in about 5 to 15 weight percent and optionally includes a softening comonomer, e.g., iso- or n-butylacrylate, to produce a softer terpolymer. The softening comonomer 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.

[0077] In another embodiment, the thermoplastic resin composition includes at least one high acid ionomer, to produce a composition for use in a golf ball for low spin rate and maximum distance. In this aspect, the acrylic or methacrylic acid is present in about 15 to about 35 weight percent, making the ionomer a high modulus ionomer. In one embodiment, the high modulus ionomer includes about 16 percent by weight of a carboxylic acid, preferably from about 17 percent to about 25 percent by weight of a carboxylic acid, more preferably from about 18.5 percent to about 21.5 percent by weight of a carboxylic acid. In some circumstances, an additional comonomer such as an acrylate ester (i.e., iso- or n-butylacrylate, etc.) can also be included to produce a softer terpolymer. The additional comonomer 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.

[0078] Consequently, examples of a number of copolymers suitable for use to produce the high modulus ionomers 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, and the like.

[0079] The inorganic metal compound may include any compound capable of neutralizing the acid groups in the thermoplastic resin component. For example, monoxide or hydroxide may be used with the present invention. High reactivity with the thermoplastic and the absence of organic compounds in the reaction by-products enable the degree of neutralization of the present invention. Examples of metal ions that may be used in the inorganic metal compound include, but are not limited to, lithium (Li), sodium (Na), potassium (K), calcium (Ca), barium (Ba), magnesium (Mg), zinc (Zn), aluminum (Al), nickel (Ni), iron (Fe), copper (Cu), manganese (Mn), tin (Sn), lead (Pb), and cobalt (Co). To achieve the unique combination of a high degree of neutralization and good flow, the neutralization of the composition preferably involves neutralization of the acid groups with transition metal ions, e.g., Zn, and alkali metal and/or alkaline earth metal ions, e.g., Li, Na, Ca, and Mg. Because transition metal ions have weaker ionic cohesion than alkali metal and alkaline earth metal ions, however, the use of transition metal ions to neutralize some of the acid groups may provide a substantial improvement in the flow characteristics. The ratio between the transition metal ions and the alkali metal and/or alkaline earth metal ions may be adjusted as appropriate. For example, in one embodiment, a ratio of the transition metal ion to alkali metal or alkali earth metal ions is from about 10:90 to about 90:10. In another embodiment, the ratio is about 20:80 to about 80:20 transition metal ion to alkali metal or alkali earth metal ion.

[0080] Thus, non-limiting examples of inorganic metal compounds may include basic inorganic fillers containing the above metal ions, such as oxides, acetates, hydroxides, carbonates, nitrates, and derivatives of Li, Na, K, Mg, Ca, Ba, Mn, Ni, Cu, Zn, and Al metal ions. In one embodiment, the inorganic metal compound includes magnesium oxide, magnesium hydroxide, magnesium carbonate, zinc oxide, zinc acetate, sodium hydroxide, sodium carbonate, calcium oxide, calcium hydroxide, lithium oxide, lithium hydroxide, and mixtures thereof.

[0081] The highly neutralized polymer composition may be prepared by mixing and heating the thermoplastic resin component, the oxa acid, oxa salt, or combination thereof, and the inorganic metal compound or organic amine compound in any well-known manner. For example, heat mixing may be achieved by mixing the components in an internal mixer, such as a twin-screw extruder, a Banbury mixer, or a kneader, and heating the composition at a temperature of about 150° C. to about 250° C. Where various additives are to be added, any suitable method may be used to incorporate the additives together with the essential components. For example, the essential components and the additives are simultaneously heated and mixed. Alternatively, the essential components are premixed before the additives are added thereto and the overall composition heated and mixed.

[0082] The highly neutralized polymer may include fatty acids, such as those disclosed in U.S. Patent Publication No. 2003/0013549, which is incorporated in its entirety by reference herein, providing that all of the fatty acids are neutralized. That is, the excess fatty acids are neutralized with excess metallic salt. As discussed, highly neutralized polymers formed from fatty acids typically have processability problems, which usually stem from a very low melt flow index. However, too high of a melt flow index may also cause processing problems. Therefore, the highly neutralized polymer of the present invention preferably has a melt flow index of about 0.5 g/10 min or greater at a temperature of 190° C. under a load of 2100 g. In addition, the melt flow index of the highly neutralized polymer is preferably no greater than about 20 g/10 min, preferably about 15 g/10 min or less. In one embodiment, the melt flow index of the highly neutralized polymer composition is about 1.0 g/10 min or greater. In yet another embodiment, the melt flow index is about 1.5 g/10 min or greater. In still another embodiment, the melt flow index if about 2 g/10 min or greater.

[0083] In addition, the specific gravity of the highly neutralized polymer is not critical, however, preferably the specific gravity is about 0.9 or greater. In one embodiment, the specific gravity of the highly neutralized polymer is about 1.5 or less. For example, the specific gravity of the highly neutralized polymer may be from about 0.9 to about 1.3.

[0084] Saponified Polymers and Polymer Blends

[0085] The compositions of the invention may also include saponified polymers. As used herein, the terms “saponified polymer” and “saponified ionomer” refer to a polymer including at least one olefin and at least one unsaturated monomer that contains a pendant ester group, where at least some of the pendant ester groups have been hydrolyzed or saponified. Saponified ionomers differ from prior art ionomers in that any pendant groups that are not modified by the saponification process are ester groups in contrast to the pendant carboxylic acid groups that remain after neutralization in prior art ionomers.

[0086] Saponified polymers useful in the invention can be made from polymers of formula 1: 10

[0087] wherein:

[0088] R ₁₂ and R ₁₄ are independently hydrogen, alkyl such as methyl, ethyl, and branched or straight chain propyl, butyl, pentyl, hexyl, heptyl, and octyl;

[0089] R ₁₃ and R ₁₅ are independently hydrogen, lower alkyl including C ₁ ⁻ C ₅ carbocyclic, or aromatic;

[0090] R ₁₆ is selected from the group consisting of C _n H _2n+1 , for n=1 to 18 (which includes, for example, CH ₃ , C ₂ H ₅ , C ₃ , H ₇ , C ₄ , H ₉ , C ₅ H ₁₁ , C ₆ H, ₁₃ , C ₇ , H ₁₅ , C ₉ H ₁₉ , C ₁₀ , H ₁₂ ,) and phenyl, in which from 0 to 5 H within R,6 can be replaced by substituents selected from the group consisting of COOH, SO ₃ H, NH ₂ , succinic anhydride and their salts, or R ₁₆ can be replaced by substituents selected from the group consisting of F, Cl, Br, I, OH, SH, epoxy, silicone, lower alkyl esters, lower alkyl ethers, and aromatic rings, wherein optionally R ₁₅ and R ₁₆ can be combined to form a bicyclic ring;

[0091] R ₁₇ and R ₁₈ are independently hydrogen, lower alkyl including C ₁ -C ₅ , carbocyclic, or aromatic;

[0092] wherein 1, m and n are the relative percentages of each co-monomer. Saponified polymers can also be formed from polymers of formula II: 11

[0093] wherein:

[0094] R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , and R ₁₆ are as defined above; and wherein o, p and q are the relative percentages of each co-monomer;

[0095] from polymers of formula III: 12

[0096] wherein:

[0097] R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , and R ₁₆ are as defined above; and wherein r, s and t are the relative percentages of each co-monomer; and from polymers of formula IV: 13

[0098] wherein:

[0099] R ₁₂ , R ₁₃ , R ₁₄ , R ₁₅ , and R ₁₆ are as defined above; R ₁₉ is hydrogen, lower alkyl including C,-C ₅ , carbocyclic, or aromatic; R _2o is hydrogen or lower alkyl including C ₁ -C ₅ ; and R ₂₁ , is hydrogen, or is selected from the group consisting of C _n H _2n+1 , for n=1 to 18 and phenyl, in which from 0 to 5 H within R ₂₁ , can be replaced by substituents selected from the group consisting of COOH, S0 ₃ H, NH ₂ , succinic anhydride and their salts, or R ₂₁ , can be replaced by substituents selected from the group consisting of F, Cl, Br, I, OH, SH, epoxy, silicon, lower alkyl esters, lower alkyl ethers and aromatic rings, wherein optionally R ₂₀ and R ₂₁ can be combined to form a bicyclic ring; and wherein u, v and w are the relative percentages of each co-monomer. In addition, saponified polymers can be formed from polymers of formula V: 14

[0100] wherein:

[0101] R ₁₂ -R ₁₆ are as defined above; R ₂₂ is hydrogen, lower alkyl including C ₁ -C ₅ , carbocyclic, or aromatic; R ₂₃ is hydrogen or lower alkyl including C,-C ₅ ; and R ₂₄ is hydrogen or is selected from the group consisting of C _n H _2n+1 for n=1 to 18 and phenyl, in which from 0 to 5 H within R ₂₄ can be replaced by substituents selected from the group consisting of COON, SO ₃ H, NH ₂ , succinic anhydride and their salts, or R ₂₄ can be replaced by substituents selected from the group consisting of F, Cl, Br, 1, OH, SH, epoxy, silicone, lower alkyl esters, lower alkyl ethers and aromatic rings; and R ₂₄ is the same as R ₂₁ wherein optionally R ₂₃ and R ₂₄ can be combined to form a bicyclic ring; and wherein x, y and z are the relative percentages of each co-monomer.

[0102] In each of the polymers described above, R ₂ and R ₃ can be any combination of alkyl, carbocyclic or aromatic groups, for example, 1-cyclohexylpropyl, benzyl cyclohexylmethyl, 2-cyclohexylpropyl, 2,2-methylcyclohexylpropyl, 2,2-methylphenylpropyl, 2,2-methylphenylbutyl. Comonomer units according to the above formulae are easily manufactured according to techniques and synthetic strategies well known to the skilled artisan. These comonomers are also commercially available from a number of commercial sources.

[0103] As used herein with regard to saponified polymers and oxa esters, the phrase “branched or straight chain alkyl” means any substituted or unsubstituted acyclic carbon-containing compounds. Examples of alkyl groups include lower alkyl, for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl or tert-butyl; upper alkyl, for example, octyl, nonyl, decyl, and the like; and lower alkylene, for example, ethylene, propylene, butylene, pentene, hexene, heptene, octene, norbomene, nonene, decene and the like. The ordinary skilled artisan is familiar with numerous linear and branched alkyl groups, which are within the scope of the present invention.

[0104] In addition, such alkyl groups may also contain various substituents in which one or more hydrogen atoms has been replaced by a functional group. Functional groups include, but are not limited to hydroxyl, amino, carboxyl, sulfonic amide, ester, ether, phosphates, thiol, nitro, silane and halogen (fluorine, chlorine, bromine and iodine), to mention but a few.

[0105] As used herein, “substituted and unsubstituted carbocyclic” means cyclic carbon-containing compounds, including, but not limited to cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, and the like. Such cyclic groups may also contain various substituents in which one or more hydrogen atoms has been replaced by a functional group. Such functional groups include those described above, and lower alkyl groups having from 1-28 carbon atoms. The cyclic groups of the invention may further include a heteroatom.

[0106] As used herein, “substituted and unsubstituted aryl groups” refers to any functional group including a hydrocarbon ring having a system of conjugated double bonds, such as phenyl, naphthyl, anisyl, toluyl, xylenyl and the like. According to the present invention, aryl also includes heteroaryl groups, e.g., pyrimidine or thiophene. These aryl groups may also be substituted with any number of a variety of functional groups. In addition to the functional groups described above in connection with substituted alkyl groups and carbocyclic groups, functional groups on the aryl groups can include nitro groups.

[0107] As used herein, “heterocyclic groups” means closed cyclic carbon-containing compounds wherein one or more of the atoms in the ring is an element other than carbon, e.g. sulfur, nitrogen, etc, including but not limited to pyridine, pyrole, furan, thiophene, and purine.

[0108] Saponified polymers can be random, block or alternating polymers and may be made by blending two, three, four, five or more different monomers according to processes well known to one of ordinary skill in the art. Additionally, the subject polymers may be isotactic, syndiotactic or atactic, or any combination of these forms of types of polymers. The pendant groups creating the isotactic, syndiotactic or atactic polymers can be chosen to determine the interactions between the different polymer chains making up the resin to control the final properties of the resins used in golf ball covers. Aromatic and cyclic olefins can be used in the present invention as well as such specific groups as methyl and phenyl.

[0109] The comonomers described herein can be combined in a variety of ways to provide a final copolymer with a variety of characteristics. The letters k, n, q, t and w represent numbers that can independently range from 1-99 percent, preferably from 10-95 percent, more preferably from 10-70 percent and, most preferably, from about 10-50 percent. The coefficients e, o, r, u and x can independently range from 99-1 percent, preferably from 90-5 percent, more preferably from 90-30 percent, and most preferred from 90-50 percent, and m, p, s, v and y can independently range from 0 to 49 percent.

[0110] Graft copolymers of the saponified polymers described above can also be prepared for use in forming golf balls. For example, graft polymers can be produced such that the graft segment making up the linkage between polymer chains includes an anhydride, wherein “anhydride” is taken to mean a compound having the formula: 15

[0111] wherein R ₂₅ and R ₂₆ are the same or different and are chosen from among hydrogen, linear or branched chain alkyl and substituted or unsubstituted carboxylic groups. Alternately, however, other grafting agents containing double or triple bonds can be used. Examples of these materials include, but are not limited to, acrylates, styrene and butadiene.

[0112] Grafting the polymer molecules of the present invention can be accomplished according to any technique known in the art. See, e.g., Block and Graft Copolymers , by R. Ceresa, pub. by Butterworths, London, U.S. (1962), incorporated by reference herein. It is preferred that any grafting of the polymers of the present invention be accomplished by adding from about 1 to about 50 percent, or preferably from about 1 to about 25 percent and most preferably from about 1 to about 15 percent of a grafting agent, such as an anhydride according to the formula above. The grafting agents can be added either as a solid or a non-aqueous liquid, to a polymer according to the present invention. Such post reaction grafting can make the final grafted polymer more flexible.

[0113] In one embodiment, the polymers used for saponification include: (1) a first monomeric component including an olefinic monomer having from 2 to 8 carbon atoms; (2) a second monomeric component including an unsaturated carboxylic acid based acrylate class ester having from 4 to 22 carbon atoms; and (3) an optional third monomeric component including at least one monomer selected from the group consisting of carbon monoxide, sulfur dioxide, an anhydride monomer, an unsaturated monocarboxylic acid, an olefin having from 2 to 8 carbon atoms and a vinyl ester or a vinyl ether of an alkyl acid having from 4 to 21 carbon atoms.

[0114] Polymers that can be saponified for use in the present invention can be synthesized by a variety of methods, including metallocene catalysis, since it is well known in the art of polymer synthesis that many different synthetic protocols can be used to prepare a given compound. Different routes can involve more or less expensive reagents, easier or more difficult separation or purification procedures, straightforward or cumbersome scale-up, and higher or lower yield. The skilled synthetic polymer chemist knows well how to balance the competing characteristics of synthetic strategies. Thus, the saponified polymers useful in the present invention are not limited by the choice of synthetic strategy, and any synthetic strategy that yields the saponified polymers described above can be used.

[0115] One non-limiting example of saponified polymer synthesis includes adding a metal base or metal salt in the form of a solid or a solution to a polymer, such as the polymers described above. The metal base includes at least one metallic cation, such as lithium, sodium, potassium, cesium, magnesium, calcium, barium, zinc, manganese, copper, aluminum, and at least one anion, such as hydroxide, alkoxide, acetate, carbonate, bicarbonate, oxide, formate, or nitrate. In one embodiment, the metal base is in the form of a solid, such as a powder or a pellet. Powdered bases used in the invention preferably have an average powder particle diameter of at least 1 to 500 microns, more preferably 10 to 100 microns. In the case of pellets, substantially any commercially available pellet particle size can be used. In another embodiment, the metal base can be added in the form of a solution. Preferably, the solution is non-aqueous so that difficulties arising from incomplete removal of water during subsequent processing and use are avoided. Such non-aqueous solutions typically include solvents such as alcohol, acetic acid and acetic anhydride, although other solvents may, of course, be used.

[0116] The polymers described herein may be saponified or hydrolyzed by introducing the polymer into an extruder inlet zone, and melting and mixing the polymer in the inlet zone; passing the molten polymer through an addition zone within the extruder downstream from the inlet zone; and adding a metal base into the molten polymer as it passes through the addition zone. The base may be added to the molten polymer under saponification conditions until the polymer is at least partially saponified, as indicated by, for example, its melt index or by titrating versus an acid.

[0117] However, when using a metal base, the metal base is preferably mixed with the polymer under non-saponification conditions. Instead of simultaneously mixing and saponifying or hydrolyzing as practiced in the prior art, these operations are carried out separately. In the first step, the polymer is heated to a substantially molten state at a temperature typically between about 50-350° C., depending upon the polymer chosen, to facilitate subsequent mixing with a metal base. This pre-heating step assures a greater degree of homogeneity in the final product, and provides a final product having correspondingly improved properties.

[0118] In the next step, the metal base is added to the molten polymer, and the polymer and metal base are extensively mixed under conditions in which no substantial hydrolysis occurs. A sufficient amount of metal base must be added overall to obtain a degree of saponification of the polymer between about 1 and about 50 percent. The mixing is carried out at a temperature slightly higher than the melting temperature of the polymer. For mixing on an extruder, the screw speed can be varied between about 20-500 rpm, depending upon the material's viscosity, i.e., the higher the viscosity, the greater the screw rpm required. Furthermore, as would be well understood by one of ordinary skill in the art, the depth of the conveying element of the extruder is chosen to prevent substantial hydrolysis of the material during mixing.

[0119] Alternately, the mixing may be accomplished using a roll mill. In such a case, the cylinder roll speed is adjusted to between about 5-100 rpm depending upon the viscosity of the material. Additionally, the mill gap is adjusted as necessary to control the amount of shear, and thus the degree of hydrolysis. The metal base may be added all at once to the molten polymer, or alternately it may be introduced in batches or stages.

[0120] In a third step, conditions are provided such that a hydrolysis or saponification reaction occurs between the polymer and the metal base. Saponification is achieved by continuous mixing of the polymer and base at an elevated temperature, which is substantially higher than the melting point temperature.

[0121] This process offers several improvements over the methods disclosed in the prior art. First, it provides for greater ease of mixing of the reactants before the reaction begins. Because the melt viscosity of the non-salt polymer is much lower than the salt polymer form, the melt mixing of the polymer and metal base is more readily carried out with lower input power requirements. Additionally, mixing of polymer and metal base is more uniform because there are no substantially hydrolyzed or saponified regions of high melt viscosity present within regions that have not yet reacted and, therefore, have low melt viscosity. Furthermore, the degree of mixing or dispersion of the base in the polymer is more easily controlled since melt viscosity is more uniform throughout the volume of molten polymer. Using this method, once substantial saponification begins, the reaction is thought to be more uniform than the methods previously disclosed.

[0122] This process is preferably accomplished using a twin screw extruder wherein the twin screw extruder includes melting, addition, and mixing zone means. The process can further be accomplished using a master batch including a concentrated amount of metal base in a polymer, with the same or different composition as the polymer introduced into the inlet zone, wherein the master batch is added from a side-stream extruder. The side-stream extruder can be a twin screw extruder including melting, addition, and mixing zone means.

[0123] Alternatively, another process useful for saponification according to the invention involves introducing the polymer into an inlet zone of an extruder, and melting and mixing the polymer in the inlet zone; passing the molten polymer through at least two addition zones connected in series; and adding a portion of a metal base into the molten polymer as it passes through each addition zone until the polymer is at least partially saponified.

[0124] This process can be accomplished using a twin screw extruder wherein the twin screw extruder includes melting, addition, and mixing zone means. The process can further be accomplished using a single or a plurality of master batches including a concentrated amount of metal base in a polymer, with the same or different composition as the polymer introduced into the inlet zone, and with the same or different amount of metal base as the other master batches, wherein the master batch is added from a side-stream extruder. The process can be accomplished with a single or with multiple side-stream extruders which are twin screw extruders including melting, addition, and mixing zone means.

[0125] Oxa Esters

[0126] The compositions of the invention may also include at least one oxa ester or oxa ester blend. As used herein, the term oxa ester may include:

[0127] (a) monoesters of the formula: 16

[0128] b) diesters of formula: 17

[0129] wherein n is an integer greater than or equal to 1, preferably from 1 to 27, R ₁ and R ₃ are typically CH ₃ , but may be any organic moiety selected from the group consisting of a linear or branch chained alkyl, a substituted or unsubstituted carbocyclic or heterocyclic groups, and R ₂ is H or an organic moiety selected from the group consisting of linear and branch chained alkyl, substituted and unsubstituted carbocyclic, and heterocyclic groups;

[0130] (c) polymers of formula 18

[0131] (d) polymers of formula 19

[0132] and (e) polymers of formula 20

[0133] where R ₄ and R ₅ are independently selected from the group consisting of hydrogen or an alkyl group containing from 1 to 8 carbon atoms;

[0134] a is an integer in the range of from 1 to about 2,000 and preferably from 1 to about 1000;

[0135] b, d and g are independently an integer in the range of from about 1 to about 10,000 and preferably is in the range of from about 10 to about 1,000 and most preferably in the range of from about 50 to about 200;

[0136] c is an integer in the range of from 1 to 2000

[0137] e is an integer in the range of from 1 to about 6,000, preferably from 1 to about 1,200, most preferably from about 1 to about 250;

[0138] f is an integer from about 1 to about 200;

[0139] R ₆ is an alkylene containing from 2 to 12 carbon atoms or is an oxyalkylene group of formula:

—[(CH ₂ ) _h —O—] _i —(CH ₂ ) _j —

[0140] where h is an integer in the range of from about 2 to about 5, i is an integer in the range of from about 0 to about 2,000 and preferably from 0 to 12, and j is an integer in the range of from about 2 to about 5;

[0141] R ₇ is an alkylene unit containing from 2 to 8 methylene units; p 1 R ₈ is selected from the group consisting of —C(R ₉ )(R, ₁₀ )—, (CH ₂ ) ₃ —0—, —CH ₂ CH ₂ 0—CH ₂ ; —CR ₁₁ H—CH ₂ ,—(CH ₂ ) ₄ —(CH ₂ ,) _k —0—C(0)—, and ⁻ (CH ₂ )k ⁻ C(O) ⁻ CH ₂ ;

[0142] R ₉ and R ₁₀ are independently hydrogen or an alkyl containing from 1 to about 8 carbon atoms;

[0143] R ₁₁ is hydrogen or methyl;

[0144] k is an integer of from about 2 to about 6;

[0145] G represents the residue minus from 1 to e hydrogen atoms from the hydroxyl groups of an alcohol previously containing from 1 to about 200 hydroxyl groups; and

[0146] L is an integer from about 1 to about 200. The term “about,” as used herein in connection with one or more numbers or numerical ranges, should be understood to refer to all such numbers, including all numbers in a range.

[0147] In one embodiment, the composition of the invention includes about 35 to about 1 part oxa ester, based on 100 parts by weight of the composition. In another embodiment, the composition of the invention includes about 25 parts to about 1 part oxa ester, based on 100 parts by weight of the composition. In yet another embodiment, the oxa ester is included in the composition of the invention in about 15 parts to about 1 part, based on 100 parts by weight of the composition.

[0148] Oxa esters may be blended with other polymers or ionomers, according to methods well known in the art, to form compositions useful for forming golf balls. For example, oxa esters may be blended with saponified polymers to form saponified polymer/oxa ester blends, which be used alone or blended with thermoplastic ionomers, such as ethylene methacrylic acid ionomers and ethylene acrylic acid ionomers and their terpolymers, which are sold commercially under the trade names SURLYN® and IOTEK® by DuPont and Exxon respectively.

[0149] The terms “saponified polymer/oxa ester blend” and “saponified/oxa ester blend”, as used herein, refers to any polymer blend that includes at least one saponified polymer and at least one oxa ester. As used herein with regard to a polymer blend, the term “compatible” refers to a blend of two or more polymers, having useful golf ball properties, that is homogeneous on a macroscopic scale. Compatible blends may be miscible (i.e., homogeneous on a microscopic scale), or at least partially immiscible (i.e., heterogeneous on a microscopic scale, but homogeneous on a macroscopic scale) and have a “reduced interfacial tension” at the polymer interface. The term “incompatible” refers to a mixture of at least two polymers that is heterogeneous on both a microscopic scale and a macroscopic scale, such that useful golf ball properties, such as durability, are lacking.

[0150] In the aspect of the invention involving saponified polymer/oxa ester blends, a saponified polymer with ionomeric character may first be blended with the other similar polymers, having a different metal base cation or distribution of cationic species than used to make the first saponified polymer, to yield a blend with desirable golf ball properties. Alternatively, two different saponified polymers with ionomeric character, having the same metal base cation can be blended to yield a useful blend. The two polymers can differ in their degree of hydrolysis, degree of subsequent acidification, molecular weight, molecular weight distribution, tacticity, blockiness, etc.

[0151] For example, the other polymers that can be used in conjunction with saponified polymer/oxa ester blends in golf ball covers include, but are not limited to: block copolymers of a poly(ether-ester), such as HYTREL® available from DuPont, block copolymers of a poly(ether-amide), such as PEBAX® available from Atofina, styrene-butadiene-styrene block copolymers, such as the KRATON D® grades available from Shell Chemical, styrene-(ethylene-propylene)-styrene or styrene-(ethylene-butylene)-styrene block copolymers, such as the KRATON G® series from Shell Chemical, either of the KRATON®s with maleic anhydride or sulfonic graft or functionality, such as the KRATON FD® or KRATON FG® series available from Shell Chemical, olefinic copolymers, such as the ethylene-acrylate or ethylene methacrylate series available from Quantum, metallocene catalyzed polymers, including ethylene-octene copolymers made from metallocene catalysts, such as those available as the AFFINITY® or ENGAGE® series from Dow, and ethylene-alpha olefin copolymers and terpolymers made from metallocene catalysts, available as the EXACT® series from Exxon, block poly(urethane-ester) or block poly(urethane-ether) or block poly(urethane-caprolactone), such as the ESTANE® series available from BF Goodrich, polyethylene glycol, such as CARBOWAX® available from Union Carbide, polycaprolactone, polycaprolactam, polyesters, such as EKTAR® available from Eastman, polyamides, such as nylon 6 or nylon 6,6, available from DuPont and ICI, ethylene-propylene-(diene monomer) terpolymers and their sulfonated or carboxylated derivatives, and PP/EPDM and dynamically vulcanized rubbers, such as SANTOPRENE® from Monsanto.

[0152] In one embodiment, the saponified polymer/oxa ester blend includes about 65 parts to about 99 parts of at least one saponified polymer and about 35 parts to about 1 part of at least one oxa ester, based on 100 parts by weight of the saponified polymer/oxa ester blend. In another embodiment, the saponified polymer/oxa ester blend includes about 75 parts to about 99 parts saponified polymer and about 25 parts to about 1 part oxa ester, based on 100 parts by weight of the saponified polymer/oxa ester blend. In still another embodiment, the saponified polymer/oxa ester blend includes about 85 parts to about 99 parts of at least one saponified polymer and about 15 parts to about 1 part of at least one oxa ester, based on 100 parts by weight of the saponified polymer/oxa ester blend.

[0153] The saponified polymer/oxa ester blends of the present invention can be prepared with or without the addition of a compatibilizer, and with varying molecular architecture of blend components, such as varying molecular weight, tacticity, degrees of blockiness, etc., as is well known to those knowledgeable in the art of blending polymers.

[0154] The amounts of polymers used to form saponified polymer/oxa ester blends can vary from about 1 to about 99 parts of the saponified polymer/oxa ester blend to about 99 to about 1 parts of other polymers or ionomers, based on the total weight of polymers. More preferred ratios of about 95 to about 5 parts of the saponified polymer/oxa ester blend with about 5 to about 95 parts of one or more other polymers. Most preferred is from about 95 parts to about 10 parts of the subject saponified polymer/oxa ester blends and from about 5 to about 90 parts of the other polymer or ionomer.

[0155] Blending of the saponified polymer/oxa ester blends is accomplished in a conventional manner using conventional equipment. Good results have been obtained by mixing the resins in a solid, pelletized form and then placing the mix into a hopper which i., used to feed the heated barrel of the injection molding machine. Further mixing is accomplished by a screw in the heated barrel. For golf ball covers, the injection molding machine may be used either to make preformed half-shells for compression molding about core or for molding flowable cover stock about a core using a retractable-pin mold. Similar techniques may be used to form golf ball cores and mantle or intermediate layers situated between a cover an a core with any of the compositions of the invention. Such machines and techniques are conventional.

[0156] Compositions including oxa esters may be blended with additional ingredients noted below, for example, to be used in a golf ball cover using any conventional blending technique. For example, the present compounds may be added to a vessel containing pelletized polymer resins and heated to 300 to 500° F. Thorough mixing of the materials is accomplished by means of a screw in the heated vessel.

[0157] Additives

[0158] The compositions of the invention described above may also include various additives. For example, fillers may be added to the compositions of the invention to affect rheological and mixing properties, the specific gravity, i.e., density-modifying fillers, the modulus, the tear strength, reinforcement, and the like. The fillers are generally inorganic, and suitable fillers include numerous metals, metal oxides and salts, such as zinc oxide and tin oxide, as well as barium sulfate, zinc sulfate, calcium oxide, calcium carbonate, zinc carbonate, barium carbonate, clay, tungsten, tungsten carbide, an array of silicas, regrind (recycled core material typically ground to about 30 mesh particle), high-Mooney-viscosity rubber regrind, and mixtures thereof.

[0159] In one embodiment, the compositions of the invention can be reinforced by blending with a wide range of density-adjusting fillers, e.g., ceramics, glass spheres (solid or hollow, and filled or unfilled), and fibers, inorganic particles, and metal particles, such as metal flakes, metallic powders, oxides, and derivatives thereof, as is known to those with skill in the art. The selection of such filler(s) is dependent upon the type of golf ball desired, i.e., one-piece, two-piece, multi-component, or wound, as will be more fully detailed below. In another embodiment, the filler will be inorganic, having a density of greater than 4 g/cc, and will be present in amounts between about 5 and about 65 weight percent based on the total weight of the polymer composition.

[0160] The compositions of the invention may also be foamed by the addition of the at least one physical or chemical blowing or foaming agent. The use of a foamed polymer allows the golf ball designer to adjust the density or mass distribution of the ball to adjust the angular moment of inertia, and, thus, the spin rate and performance of the ball. Foamed materials also offer a potential cost savings due to the reduced use of polymeric material. As used herein, the term “foamed” encompasses “conventional foamed” materials that have cells with an average diameter of greater than 100 microns and “microcellular” type materials that have closed cell sizes on the order of 2 to 25 microns. Examples of conventional foamed materials include those described in U.S. Pat. No. 4,274,637. Examples of microcellular closed cell foams include those foams disclosed in U.S. Pat. Nos. 4,473,665 and 5,160,674. In this embodiment, the polymer blend may be foamed during molding by any conventional foaming or blowing agent. Preferably, foamed layers incorporating an oxa ester or oxa ester blend have a flexural modulus of at least 1,000 to about 150,000 psi.

[0161] Blowing or foaming agents useful include, but are not limited to, organic blowing agents, such as azobisformamide; azobisisobutyronitrile; diazoaminobenzene; N,N-dimethyl-N,N-dinitroso terephthalamide; N,N-dinitrosopentamethylene-tetramine; benzenesulfonyl-hydrazide; benzene-1,3-disulfonyl hydrazide; diphenylsulfone-3,3′-disulfonyl hydrazide; 4,4′-oxybis benzene sulfonyl hydrazide; p-toluene sulfonyl semicarbizide; barium azodicarboxylate; butylamine nitrile; nitroureas; trihydrazino triazine; phenyl-methyl-uranthan; p-sulfonhydrazide; peroxides; and inorganic blowing agents such as ammonium bicarbonate and sodium bicarbonate. A gas, such as air, nitrogen, carbon dioxide, etc., can also be injected into the composition during the injection molding process.

[0162] A foamed composition of the present invention may also be formed by blending microspheres with the composition either during or before the molding process. Polymeric, ceramic, metal, and glass microspheres are useful in the invention, and may be solid or hollow and filled or unfilled. In particular, microspheres up to about 1000 micrometers in diameter are useful. Generally, either injection molding or compression molding may be used to form a layer or a core including a foamed polymeric material.

[0163] Additional materials conventionally included in golf ball compositions may be added to the compositions of the invention. These additional materials include, but are not limited to, reaction enhancers, crosslinking agents, optical brighteners, coloring agents, fluorescent agents, whitening agents, UV absorbers, hindered amine light stabilizers, defoaming agents, processing aids, mica, talc, nano-fillers, and other conventional additives. Antioxidants, stabilizers, softening agents, fragrance components, plasticizers, including internal and external plasticizers, impact modifiers, foaming agents, excipients, reinforcing materials and compatibilizers can also be added to any composition of the invention. All of these materials, which are well known in the art, are added for their usual purpose in typical amounts.

[0164] Golf Ball Construction

[0165] The compositions of the invention described above are contemplated for use in golf balls of any construction, e.g., one-piece, two-piece, or three-piece design, a double core, a double cover, an intermediate layer(s), a multi-layer core, and/or a multi-layer cover, depending on the type of performance desired of the ball. As used herein, the term “multilayer” means at least two layers. For example, the compositions of the invention may be used in a core, intermediate layer, and/or cover of a golf ball, each of which may have a single layer or multiple layers.

[0166] Thus, golf balls of the invention preferably include at least one foamed or unfoamed layer formed from a composition including at least one highly neutralized polymer, oxa ester, saponified polymer/oxa ester blends, saponified polymer, saponified polymer/oxa acid blend, grafted metallocene catalyzed polymers or polymer blends, non-grafted metallocene catalyzed polymers or polymer blends and metallocene catalyzed polymers or conventional materials, including balata and ionomer cover stock. As used herein, the term “layer” includes any generally spherical portion of a golf ball, i.e., a golf ball core or center, an intermediate layer, and/or a golf ball cover.

[0167] Oxa ester and saponified polymer/oxa ester blend cover layers according to the invention may be used with conventional solid or wound cores, as well as those including other core materials, such as those described above, including, but not limited to, oxa esters, saponified polymer/oxa ester blends, oxa acids, saponified polymers, saponified polymer/oxa acid blend, grafted and non-grafted metallocene catalyzed polymers and polymer blends. Preferably, the cover of a golf ball according to the invention is formed from a polymer blend including at least one oxa ester or saponified polymer/oxa ester blend.

[0168] The compositions of the invention may be used to form any type of golf ball. In particular, two-piece golf balls including a cover surrounding a core are within the scope of the present invention, as are wound golf balls, in which a fluid, semi-solid or solid core is surrounded by an elastic synthetic material. Any type of golf ball core can be used in the golf balls of the present invention. Preferred cores, however, include some amount of cis-polybutadiene. The subject polymers may also be used in golf balls having multiple covers and/or multiple cores.

[0169] For example, FIG. 1 illustrates a golf ball according to the invention with a one-piece core. Golf ball 1 includes a core 2 and a cover 3 , wherein at least one of core 2 and cover 3 incorporates at least one foamed or unfoamed layer including at least one composition of the invention described above, e.g., oxa ester composition, saponified polymer/oxa ester blend, oxa acid composition, oxa ester/oxa acid blend, saponified polymer/oxa acid blend, highly neutralized polymer composition, or a combination thereof. Similarly, FIG. 2 illustrates a golf ball according to the invention incorporating a multi-piece core. Golf ball 10 includes a cover 12 , a core having a center 14 and at least one additional core layer 16 . Any of the cover 12 , center 14 , or core layer 16 may incorporate at least one foamed or unfoamed layer that includes at least one composition of the invention.

[0170] A golf ball incorporating an intermediate layer is illustrated in FIG. 3 , which depicts golf ball 20 , having cover 23 , core 24 , and an intermediate layer 25 situated between the cover and the core. Any of cover 23 , core 24 , and intermediate layer 25 may incorporate at least one foamed or unfoamed layer including at least one oxa ester, oxa acid, saponified polymer/oxa ester blend, oxa ester/oxa acid blend, highly neutralized polymer, or a combination thereof. Core 24 may be a one-piece core, a multi-layer core, or a wound core, having a solid or fluid center formed from one or more of the materials described below.

[0171] Core Layer(s)

[0172] The present invention contemplates the use of the compositions of the invention in one-piece cores and one-piece balls. As used herein, the term “core” means the innermost portion of a golf ball, and may include one or more layers. When more than one layer is contemplated, the core includes a center and at least one outer core layer disposed thereabout. At least a portion of the core, typically the center, is solid, hollow, or fluid-filled. As used herein, the term “fluid” means a gas, liquid, gel, paste, or the like, or a combination thereof.

[0173] In one embodiment, the core of a golf ball of the invention includes oxa esters or saponified polymer/oxa ester blends. Alternatively, the cores of the present invention may also include rubber-based materials, such as compositions including a base rubber, a crosslinking agent, and a density adjusting filler. The base rubber may includes natural or synthetic rubbers. In one embodiment, core is formed of a polybutadiene reaction product as disclosed in co-pending U.S. patent application Ser. No. 10/190,705, filed Jul. 9, 2002, entitled “Low Compression, Resilient Golf Balls With Rubber Cores,” which is incorporated in its entirety by reference herein. Crosslinking agents include metal salts of unsaturated fatty acids, such as zinc or magnesium salts of acrylic or methacrylic acid. The density adjusting filler typically includes materials such as zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate and the like.

[0174] The core may also include one or more wound layers (surrounding a fluid or solid center) including at least one tensioned elastomeric material wound about the center. In one embodiment, the tensioned elastomeric material includes natural or a synthetic elastomers or blends thereof. The synthetic elastomer preferably includes LYCRA.

[0175] In another embodiment, the tensioned elastomeric material incorporates a polybutadiene reaction product as disclosed in co-pending U.S. patent application Ser. No. 10/190,705. In yet another embodiment, the tensioned elastomeric material may also be formed from conventional polyisoprene. In still another embodiment, a polyurea composition (as disclosed in co-pending U.S. patent application Ser. No. 10/228,311, filed Aug. 27, 2002, entitled “Golf Balls Comprising Light Stable Materials and Methods for Making Same,” which is incorporated by reference in its entirety by reference herein) is used to form the tensioned elastomeric material,. In another embodiment, solvent spun polyether urea, as disclosed in U.S. Pat. No. 6,149,535, which is incorporated in its entirety by reference herein, is used to form the tensioned elastomeric material in an effort to achieve a smaller cross-sectional area with multiple strands.

[0176] The tensioned elastomeric layer may also be a high tensile filament having a tensile modulus of about 10,000 kpsi or greater, as disclosed in co-pending U.S. patent application Ser. No. 09/842,829, filed Apr. 27, 2001, entitled “All Rubber Golf Ball with Hoop-Stress Layer,” the entire disclosure of which is incorporated by reference herein. In another embodiment, the tensioned elastomeric layer is coated with a binding material that will adhere to the core and itself when activated, causing the strands of the tensioned elastomeric layer to swell and increase the cross-sectional area of the layer by at least about 5 percent. An example of such a golf ball construction is provided in co-pending U.S. patent application Ser. No. 09/841,910, the entire disclosure of which is incorporated by reference herein.

[0177] Intermediate Layer(s)

[0178] The present invention also contemplates the use of the compositions of the invention described above in intermediate layers. An intermediate layer” (also known as inner layer or mantle layer) is defined herein as a portion of the golf ball that occupies a volume between the cover and the core. Such an intermediate layer may be distinguished from a cover or a core by some difference between the golf ball layers, e.g., hardness, compression, thickness, and the like. An intermediate layer may be used, if desired, with a multilayer cover or a multilayer core, or with both a multilayer cover and a multilayer core. Therefore, an intermediate layer is also sometimes referred to in the art as an inner cover layer, an outer core layer, or a mantle layer.

[0179] In one embodiment, the intermediate layer includes at least one at least one oxa ester, conventional ionomer, oxa acid, saponified polymer/oxa acid blend, saponified polymer/oxa ester blend, highly neutralized polymer, or other polymer blend, such as those formed from a grafted or non-grafted metallocene catalyzed polymer or polymer blend, or from any other suitable polymeric material having the desired properties, including, but not limited to, block copolymers of a poly(ether-ester), such as HYTREL®, available from DuPont, block copolymers of a poly(ether-amide), such as PEBAX®, available from Elf Atochem, styrene-butadiene-styrene and styrene-(ethylene-propylene)-styrene or styrene-(ethylene-butylene)-styrene block copolymers, and their functionalized derivatives, such as KRATON D®, KRATON G®, and KRATON FG® from Shell Chemical. The layer formed from a composition of the invention preferably has a thickness of at least about 0.005 inch to about 0.125 inch and a hardness of about 15 Shore D to about 80 Shore D.

[0180] The intermediate layer may also be formed of a binding material and an interstitial material distributed in the binding material, as discussed in U.S patent application Ser. No. 10/028,826, filed Dec. 28, 2001, entitled, “Golf Ball with a Radially Oriented Transversely Isotropic Layer and Manufacture of Same,” the entire disclosure of which is incorporated by reference herein. In addition, at least one intermediate layer may also be a moisture barrier layer, such as the ones described in U.S. Pat. No. 5,820,488, which is incorporated in its entirety by reference herein. The intermediate layer may also be formed from any of the polyurethane, polyurea, and polybutadiene materials discussed co-pending U.S. patent application Ser. No. 10/228,311.

[0181] The intermediate layer may also likewise include one or more homopolymeric or copolymeric materials, such as:

[0182] (1) Vinyl resins, such as those formed by the polymerization of vinyl chloride, or by the copolymerization of vinyl chloride with vinyl acetate, acrylic esters or vinylidene chloride;

[0183] (2) Polyolefins, such as polyethylene, polypropylene, polybutylene and copolymers such as ethylene methylacrylate, ethylene ethylacrylate, ethylene vinyl acetate, ethylene methacrylic or ethylene acrylic acid or propylene acrylic acid and copolymers and homopolymers produced using a single-site catalyst or a metallocene catalyst;

[0184] (3) Polyurethanes, such as those prepared from polyols and diisocyanates or polyisocyanates and those disclosed in U.S. Pat. No. 5,334,673;

[0185] (4) Polyureas, such as those disclosed in U.S. Pat. No. 5,484,870;

[0186] (5) Polyamides, such as poly(hexamethylene adipamide) and others prepared from diamines and dibasic acids, as well as those from amino acids such as poly(caprolactam), and blends of polyamides with SURLYN, polyethylene, ethylene copolymers, ethyl-propylene-non-conjugated diene terpolymer, and the like;

[0187] (6) Acrylic resins and blends of these resins with poly vinyl chloride, elastomers, and the like;

[0188] (7) Thermoplastics, such as urethanes; olefinic thermoplastic rubbers, such as blends of polyolefins with ethylene-propylene-non-conjugated diene terpolymer; block copolymers of styrene and butadiene, isoprene or ethylene-butylene rubber; or copoly(ether-amide), such as PEBAX, sold by ELF Atochem of Philadelphia, Pa.;

[0189] (8) Polyphenylene oxide resins or blends of polyphenylene oxide with high impact polystyrene as sold under the trademark NORYL by General Electric Company of Pittsfield, Mass.;

[0190] (9) Thermoplastic polyesters, such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate/glycol modified and elastomers sold under the trademarks HYTREL by E. I. DuPont de Nemours & Co. of Wilmington, Del., and LOMOD by General Electric Company of Pittsfield, Mass.;

[0191] (10) Blends and alloys, including polycarbonate with acrylonitrile butadiene styrene, polybutylene terephthalate, polyethylene terephthalate, styrene maleic anhydride, polyethylene, elastomers, and the like, and polyvinyl chloride with acrylonitrile butadiene styrene or ethylene vinyl acetate or other elastomers; and

[0192] (11) Blends of thermoplastic rubbers with polyethylene, propylene, polyacetal, nylon, polyesters, cellulose esters, and the like.

[0193] In one embodiment, the intermediate layer includes polymers, such as ethylene, propylene, butene-1 or hexane-1 based homopolymers or copolymers including functional monomers, such as acrylic and methacrylic acid and fully or partially neutralized ionomer resins and their blends, methyl acrylate, methyl methacrylate homopolymers and copolymers, imidized, amino group containing polymers, polycarbonate, reinforced polyamides, polyphenylene oxide, high impact polystyrene, polyether ketone, polysulfone, poly(phenylene sulfide), acrylonitrile-butadiene, acrylic-styrene-acrylonitrile, poly(ethylene terephthalate), poly(butylene terephthalate), poly(ethelyne vinyl alcohol), poly(tetrafluoroethylene) and their copolymers including functional comonomers, and blends thereof.

[0194] As briefly mentioned above, the intermediate layer may include ionomeric materials, such as ionic copolymers of ethylene and an unsaturated monocarboxylic acid, which are available under the trademark SURLYN® of E. I. DuPont de Nemours & Co., of Wilmington, Del., or IOTEK® or ESCOR® of Exxon. These are copolymers or terpolymers of ethylene and methacrylic acid or acrylic acid totally or partially neutralized, i.e., from about 1 to about 100 percent, with salts of zinc, sodium, lithium, magnesium, potassium, calcium, manganese, nickel or the like. In one embodiment, the carboxylic acid groups are neutralized from about 10 percent to about 100 percent. The carboxylic acid groups may also include methacrylic, crotonic, maleic, fumaric or itaconic acid. The salts are the reaction product of an olefin having from 2 to 10 carbon atoms and an unsaturated monocarboxylic acid having 3 to 8 carbon atoms.

[0195] The intermediate layer may also include at least one ionomer, such as acid-containing ethylene copolymer ionomers, including E/X/Y terpolymers where E is ethylene, X is an acrylate or methacrylate-based softening comonomer present in about 0 to 50 weight percent and Y is acrylic or methacrylic acid present in about 5 to 35 weight percent. The ionomer also may include so-called “low acid” and �