WO2000040306A1

WO2000040306A1 - Improvement of golf ball cover using organometallic compounds

Info

Publication number: WO2000040306A1
Application number: PCT/US1999/031189
Authority: WO
Inventors: Hyun Kim; Dean A. Snell
Original assignee: Taylor Made Golf Company, Inc.
Priority date: 1999-01-06
Filing date: 1999-12-29
Publication date: 2000-07-13

Abstract

A composition for use in golf balls (1) comprising base material and 0.01-20phr of at least one organometallic compound chosen from the group consisting of titanates, zirconates, aluminates and silicates. Preferred base materials are elastomers, ionomers, and combinations thereof. The compositions of the present invention have improved rheological and mechanical properties which result in improved shear resistance and improved durability during repeated hitting of golf balls having covers (2) and/or mantles (4) comprising the compositions of the invention.

Description

IMPROVEMENT OF GOLF BALL COVER USING ORGANOMETALLIC

COMPOUNDS

Field of the Invention

The present invention relates generally to golf balls, more particularly to the use of organometallic compounds to improve the rheological and mechanical properties of polymer blends used to make golf ball covers and mantles. The improvement which results from the use of the organometallic compounds are directly related to the improved durability of a golf ball during repeated hitting.

Background of the Invention Modern golf balls are of multi-piece design and may comprise any of a multitude of different materials. Two-piece golf balls consist of a cover and a core, whereas three-piece golf balls consist of a cover, mantle and core. The core may be solid, liquid-filled, paste-filled, or some combination thereof. Mantles are generally solids and may comprise a mass of wound thread or one or more pieces of solid molded material. Covers may be made from a number of different materials and are preferably finished with a plurality of dimples which affect the flight characteristics of the ball.

One class of materials in general use for golf ball covers are ionomers. Ionomers, or ionomeric resins, are polymers which contain ionic groups, such as a carboxylic acid group, or ionic salts. Types of ionomers are distinguished in part by the type of metal ion, the acid content, and the degree of neutralization. There are a wide variety of ionomers available commercially including those sold as Surlyn by Du Pont and those sold as Iotek by Exxon.

One type of ionomer, high acid ionomers, have a high stiffness and a high level of resilience. Covers made from these materials impart a good initial velocity to the ball, which aids the ball in travelling a long distance when hit. However, the covers made from these materials have a very high Shore D hardness, which imparts a hard feel to the ball and a low spin rate, which makes shot distance hard to control when using short irons. Furthermore, the hardness of the material contributes to a brittleness that causes the ball to have low durability and to crack after multiple hits with a driver.

Another type of ionomers, the very low modulus ionomers or VLMI, are low in stiffness and hardness. However, because of these properties, they have poor resilience and result in low initial velocity to the ball when hit, which results in shorter shot distances. These materials also result in covers which are not durable in that they have poor resistance to cutting and shearing. Another class of materials used for covers are elastomers. The performance characteristics of an elastomer cover can vary widely with the grade used. Some commonly used thermoplastic elastomers are polyester elastomers, polyamide elastomers, and polyurethane elastomers. Other materials have been proposed for use in golf ball covers, but as with those listed above, it is difficult to find a single material which will form a golf ball cover which has durability, a soft feel, and good spin characteristics while retaining high resilience and good cut and shear resistance.

Very recently, some in the field have tried layering or blending two or more materials in order to get a cover which, when all the materials are acting together, would have all the desired characteristics. One difficulty in this, is that oftentimes the materials which are to be combined have widely divergent characteristics. Thus, the materials are not very compatible, and blends or layerings of two dissimilar materials can result in delamination and poor mechanical properties rather than having benefits of each of the blended materials. When this occurs, instead of getting a blend of the desired characteristics, what is achieved is a ball which does not perform as designed.

Summary of the Invention In accordance with the present invention there is provided a golf ball cover or mantle comprising a composition formed into the golf ball cover or mantle, wherein the composition comprises 100 parts by weight of base material and 0.01-20 phr of at least one organometallic compound. The base material is a homopolymer, copolymer, terpolymer, or blend of resins selected from the group consisting of elastomers, copolyetherester elastomers, copolyetheramide elastomers, styrenic copolymers, thermoplastic elastomers having a polar group, olefmic elastomers, polyurethanes, ionomers, polyamides, and polyesters. In one preferred embodiment, the composition comprises 0.1-10 phr of at least one organometallic compound. In an especially preferred embodiment, the composition comprises 0.2-5 phr of at least one organometallic compound.

In a preferred embodiment, the organometallic compound is selected from the group consisting of titantes, zirconates, and aluminates. In especially preferred embodiments, the organometallic compound is a neoalkoxy titanate or a neoalkoxy zirconate.

In accordance with the present invention there is also provided a golf ball comprising a core and a cover, wherein the cover comprises 100 parts by weight of base material and 0.01- further comprises a mantle which may comprise 100 parts by weight of base material and 0.01-20 phr of at least one organometallic compound..

In accordance with the present invention there is further provided a method of making a golf ball cover or mantle, comprising the steps of combining 100 parts by weight of at least one base material and 0.01-20 phr of at least one organometallic compound to form a composition, mixing the composition and molding the composition to form a golf ball cover or mantle.

Brief Description of the Drawings Figure 1 is a cross-section of a golf ball of two-piece construction, comprising a core and a cover. Figure 2 is a cross-section of a golf ball of three-piece construction, comprising a core, mantle, and cover.

Detailed Description of the Preferred Embodiment Most modern golf balls are of two- or three-piece design. A two-piece golf ball 1 is pictured in Figure 1. It comprises a core 3 and a cover 2, upon the surface of which is a plurality of dimples. An example of a three-piece golf ball 5 is shown in Figure 2. The three- piece ball comprises a core 3, a mantle 4, and a cover 2. The core 3 may be solid, liquid-filled or paste filled, the mantle 4 may be solid or comprised of one or more layers or made of wound thread, and the surface of the cover 2 generally has a plurality of dimples thereupon. The compositions of the present invention are suitable for use as a cover or mantle for either kind of ball.

Furthermore, a golf ball cover or mantle may comprise one or more layers as is known in the art. A single golf ball may have both a multi-layer mantle and a multi-layer cover. If there is more than one layer in a cover or mantle, different layers may comprise the same material or different materials, including the compounds of the present invention. Although the present invention is described in terms of use of the compositions in golf ball covers or in golf balls having covers of the compositions comprising organometallic compounds, it is to be understood that such description is for the sake of simplicity only. Description of the present invention in terms of covers is not intended to limit the scope of the invention which includes use of the compounds described herein in golf ball mantles. To improve the control and the feeling of a golf ball, it is desirable to use a soft cover material or to somehow decrease the hardness of a relatively hard cover material to a hardness of less than about 55 Shore D. At the same time, the cover material must have a high coefficient of restitution (C.O.R.) and demonstrate good resistance to damage such as cutting when it is hit by a golf club. It is difficult to satisfy all of these requirements. In general, when a material has the right softness and high C.O.R., the durability does not meet the requirements or when the durability and the softness are achieved, the coefficient of restitution is not high enough. Addition of an organometallic compound can improve the mechanical properties and/or rheological properties of a polymeric material. Thus, addition of an organometallic compound to a composition having good softness and C.O.R. allows for the durability of that material to be increased without losing the good properties of that material.

The use of monoalkoxy and neoalkoxy titanates in the cores of golf balls is the subject of the invention disclosed in U.K. Patent Application No. 2 317 897. Those organometallic compounds were used as coupling agents to create a bond between the organic phase of a rubber compound and the inorganic phase of fillers. The U.K. patent reference does not teach or suggest the use of organometallic compounds other than titanates, nor does it teach or suggest that the compounds of that invention or the organometallic agents used to form the compounds would have any utility in golf ball covers or mantles, or in increasing the durability of such covers and mantles.

The golf ball cover compositions of the present invention comprise at least one organometallic compound and a base material, which comprises one or more polymeric materials or resins. The base material may be a homopolymer, copolymer, terpolymer, or blends of resins which would give hardness less than 65 Shore D, preferably less than 55

Shore D. Organometallic Compounds

Preferred organometallic compounds for use in the compositions of the present invention are those which have central metals such as Titanium (Ti), Silicon (Si), Aluminum (Al) and Zirconium (Zr). organometallic compounds have distinct beneficial physical and rheological properties when they are introduced into a polymeric system, such as improvement in dispersion and rheology, improvement in mechanical properties, and promotion of adhesion.

One example of the organometallic compounds of the present invention are the organotitanates. There are several different types of organotitanates, according to the formula below, which differ in the number and type of substituents.

1 2 3 4 5 6

(RO)_m - Ti - (0 - X - R₂ - Y)_n wherein R and R₂ are C,.₃₀ alkyl or alkenyl groups Each of the functional groups, as numbered 1-6 above, provide specific function to the molecule as a whole. Functional group 1 provides for the attachment of the hydrolyzable portion of the molecule to the surface of an inorganic or proton bearing species. Functional group 2 acts as an electric donor or acceptor causing a catalytic rearrangement and redistribution of the molecular structure. Functional group 3 affects performance as determined by the chemistry of alkylate, carboxyl, sulfonyl, phenolic, phosphate, pyrophophate, and phosphite groups which are present. Functional group 4 provides van der Waals entanglement via long carbon chains for thermoplastic impact improvement, internal lubricity for processability, plasticizing, and compatibilization. Functional group 5 provides thermoset reactivity via functional groups such as methacrylates and amines. Functional group 6 provides one, two, or three pendant organic groups allowing functionality to be controlled from first to third degree.

As mentioned above, there are many types of organometallic compounds according to the above formula. The types of organometallic compounds are as follows: monoalkoxy type

(m=l, n=3); coordinate type (m=4, n=2); chelate type (m=l, n=2); quat type (m=l, n=2 or 3); neoalkoxy type (m=l, n=3); cycloheteroatom type (m=l, n=l). The monoalkoxy type and neoalkoxy type compounds are especially preferred. Organometallic compounds of this type are available as either liquid, powder, masterbatch in powder with silica, or in pellet form with polymeric binder, and are produced by Kenrich Petrochemicals, Inc. under the brands of Ken-

React LICA, Ken-React CAPOW, and Ken-React CAPS with numeric product designations after the name which represent the many different products with different chemical structures. Examples of monoalkoxy titanate available from Kenrich Petrochemicals are: KR TTS isopropyl triisostearoyl titanate; KR 7 isopropyl dimethacryl isostearoyl titanate; KR 9S isopropyl tri(dodecyl)bezenesulfonyl titanate; KR 12 isopropyl tri(dioctyl)phosphato titanate;

KR 26S isopropyl (4-amino)bezenesulfonyl di(dodecyl)bezenesulfonyl titanate; KR 33DS alkoxy trimethacryl titanate; KR 38S isopropyl tri(dioctyl)pyrophosphato titanate; KR 39DS alkoxy triacryl titanate; and KR 44 isopropyl tri(N-ethylenediamino)ethyl titanate.

Examples of chelate titanate available from Kenrich Petrochemicals are: KR 134S di(cumyl)phenyl oxoethylene titanate; KR 138S di(dioctyl)pyrophosphate oxoethylene titanate; KR 133DS dimethacryl, oxoethylene titanate; FR 158 FS di(butyl, methyl)pyrophosphato, oxoethylene di(dioctyl)phosphito titanate; KR 121 di(dioctyl)phosphato, ethylene titanate; KR 238S di(dioctyl)pyrophosphato ethylene titanate; and KR 262ES di(butyl, methyl) pyrophosphato, ethylene titanate.

Examples of quat titanate and zirconate available from Kenrich Petrochemicals are: KR 138D 2-(N,N-dimethylamino)isobutanol adduct of di(dioctyl)pyrophosphate oxoethylene titanate; KR 158D 2-(N,N-dimethylamino)isobutanol adduct of di(butyl, methyl)pyrophosphato, oxoethylene di(dioctyl)phosphito titanate; KR 238T triethylamine adduct of di(dioctyl)pyrophosphato ethylene titanate; KR 238M methacrylate functional amine adduct of di(dioctyl)pyrophosphato ethylene titanate; KR 238 A acrylate functional amine adduct of di(dioctyl)pyrophosphato ethylene titanate; KR 238 J methacrylamide functional amine adduct of di(dioctyl)pyrophosphato ethylene titanate; KR 262 A acrylate functional amine adduct of di(dioctyl)pyrophosphato ethylene titanate; LICA 38 J methacrylamide functional amine adduct of neopentyl(diallyl)oxy, tri(dioctyl)pyrophosphato titanate; and KZ TPPJ cycloneopentyl, cyclo(dimethylaminoethyl) pyrophosphato zirconate, dimesyl salt. Examples of coordinate titanate and zirconate available from Kenrich Petrochemicals are: KR 41 B tetraisopropyl di(dioctyl)phosphito titanate; KR 46B tetraoctyl di(ditridecyl)phosphito titanate; KR 55 tetra (2,2 diallyloxymethyl)butyl, di(ditridecyl)phosphito titanate; and KZ 55 tetra (2,2 diallyloxymethyl)butyl, di(ditridecyl)phosphito zirconate. Examples of neoalkoxy titanate zirconate available from Kenrich Petrochemicals are:

LICA 01 neopentyl(diallyl)oxy, trineodecanonyl titanate; LICA 09 neopentyl(diallyl)oxy, tri(dodecyl)bezene-sulfonyl titanate; LICA 12 neopentyl(diallyl)oxy, tri(dioctyl)phosphato titanate; LICA 38 neopentyl(diallyl)oxy, tri(dioctyl)pyro-phosphato titanate; LICA 44 neopentyl(diallyl)oxy, tri(N-ethylenediamino) ethyl titanate (pictured below); LICA 97 neopentyl(diallyl)oxy, tri(m-amino)phenyl titanate (pictured below); and LICA 99 neopentyl(diallyl)oxy, trihydroxy caproyl titanate.

LICA 94 ~ neopentyl(diallyl)oxy, tri(N-ethylenediamino)ethyl titanate

H,C= :CH- -CH, ^■ O- -CH,

H₃C H₂C — C CH₂ O Ti O C₂H₄ NH C₂H₄ - NH,

3

H,C= :CH- -CH, O- ^■CH,

LICA 97 — neopentyl(diallyl)oxy, tri(m-amino)phenyl titanate

Examples of cycloheteroatom titanate and zirconate available from Kenrich

Petrochemicals are: KR OPPR Cyclo(dioctyl)pyrophosphato dioctyl titanate; KR OPP2 Dicyclo(dioctyl)pyrophosphato titanate; KZ OPPR Cyclo(dioctyl)pyrophosphato dioctyl zirconate; and KZ TPP Cyclo[dineopentyl(diallyl)]pyrophosphato dineopentyl(diallyl) zirconate.

Examples of neoalkoxy zirconate available from Kenrich Petrochemicals are: NZ 01 neopentyl(diallyl)oxy, trineodecanoyl zirconate; NZ 09 neopentyl(diallyl)oxy, tri(dodecyl)bezene-sulfonyl zirconate; NZ 12 neopentyl(diallyl)oxy, tri(dioctyl) phosphato zirconate; NZ 38 neopentyl(diallyl)oxy, tri(dioctyl)pyro-phosphato zirconate; NZ 44 neopentyl(diallyl)oxy, tri(N-ethylenediamino) ethyl zirconate (pictured below); NZ 97 neopentyl(diallyl)oxy, tri(m-amino)phenyl zirconate (pictured below); NZ 33 neopentyl(diallyl)oxy, trimethacryl zirconate; NZ 39 neopentyl(diallyl)oxy, triacryl zirconate; NZ 37 dineopentyl(diallyl)oxy, diparamino benzoyl zirconate (pictured below); and NZ 66A neopentyl (diallyl)oxy, di(3-mercapto) propionic zirconate.

NZ37 — dineopentyl(diallyl)oxy, diparamino benzoyl zirconate

NZ44 — neopentyl(diallyl)oxy, tri(N-ethylenediamino)ethyl zirconate

NZ 97 — neopentyl(diallyl)oxy, tri(m-amino)phenyl zirconate

Organoaluminates can also be used in the present invention. Examples of organoaluminates are those which have the following structures.

Where R = C₁₈H₃₇, C₂H₅. and

Where R = C₁₈H₃₇, C₂H Base Materials

Preferred base materials for use in the compositions of the present invention are homopolymers, copolymers, terpolymers, and blends of resins of the following materials: elastomers, including copolyetherester elastomers, copolyetheramide elastomers, styrenic copolymers, thermoplastic elastomers having functional or polar groups, olefinic elastomers, and polyurethanes; ionomers; polyamides; polycarbonates; and polyesters.

Examples of preferred materials of the elastomer type are: thermoplastic elastomer, thermoplastic elastomer modified with various functional or polar groups, thermoplastic rubber, thermoset rubber, thermoset elastomer, dynamically vulcanized thermoplastic elastomers, metallocene polymer or blends of thereof. Elastomers include polyetherester elastomers, polyetheramide elastomers, propylenebutadiene copolymers, modified copolymers of ethylene and propylene, styrenic copolymers including styrenic block copolymers and randomly distributed styrenic copolymers such as styrene-isobutylene copolymers, ethylene-vinyl acetate copolymers (EVA), 1 ,2-polybutadiene, and styrene-butadiene copolymers, dynamically vulcanized PP/EPDM, polyether or polyester thermoplastic urethanes as well as thermoset polyurethanes.

A preferred type of elastomer are the copolyetherester elastomers, examples of which are: polyether ester block copolymers, polylactone ester block copolymers, aliphatic and aromatic dicarboxylic acid copolymerized polyesters, and the like. Polyether ester block copolymers are copolymers comprising polyester hard segments polymerized form a dicarboxylic acid and a low molecular weight diol and polyether soft segment polymerized from an alkylene glycol having 2 to 10 carbon atoms. The polylactone ester block copolymers are copolymers with polylactone chains for the polyether as the soft segments in the above mentioned polyether ester block copolymer structures. The aliphatic and aromatic dicarboxylic acid copolymerized polyesters are generally copolymers of an acid component selected from aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid and aliphatic dicarboxylic acids having 2 to 10 carbon atoms with at least one diol component selected from aliphatic and alicyclic diols having 2 to 10 carbon atoms although blends of an aromatic polyester and an aliphatic polyester may be equally used here. Some commercially available copolyetherester elastomers are SKYPEL G130D, G135D, and G140D resins from SK

Chemicals Co.; Hytrel G3078, G3548, G4074 resins from E.I. DuPont de Nemours & Company.

An especially preferred type of elastomer are the copolyetheramide elastomers, such as polyether amide block copolymer. One suitable family of such resins is the Pebax family available from Elf Atochem. Preferred members of the Pebax family include Pebax 2533, Pebax 4033, Pebax 3533, Pebax 4533, Pebax 1205, and Pebax 5533. Blends or combinations of these and other members of the Pebax family may be prepared as well. Pebax 2533 has a hardness of about 25 shore D (ASTM D-2240), a flexural modulus of 2.1 Kpsi (ASTM D-790), and a Bayshore resilience of about 62% (ASTM D-2632). Pebax 3533 has a hardness of about 35 shore D (ASTM D-2240), a flexural modulus of 2.8 Kpsi (ASTM D-790), and a Bayshore resilience of about 59%) (ASTM D-2632). Pebax has the unusual and likely unique property of increasing in resilience while decreasing in hardness. Pebax 4033 has a hardness of about 40 shore D (ASTM D-2240), a flexural modulus of 1.3 Kpsi (ASTM D-790), and a Bayshore resilience of about 51% (ASTM D-2632). Pebax 1205 has a hardness of about 40 shore D

(ASTM D-2240), and a flexural modulus of 1.13 Kpsi (ASTM D-790). However, a small amount of Pebax 5533 (55 Shore D) or Pebax 6533 (63 Shore D) or other Pebax of lower hardness can be envisioned as long as the total hardness remains within reasonable limits. The values herein are determined at room temperature, about 18°C - 23°C, however the shore D hardness of Pebax varies little with the temperature within the range of -40°C to 80°C.

Another preferred type of elastomer are the styrenic copolymers, examples of which are: styrenebutadiene-styrene and styrene-isoprene-styrene types manufactured by Shell Chemicals under the name Kraton D rubber; strene-ethylene-butylene-styrene and styrene-ethylene-propylene-styrene types manufactured under by Shell under the name Kraton G rubber; and randomly distributed styrenic copolymers including paramethylstyrene-isobutylene

(isobutene) copolymers developed by Exxon Chemical Co.

Another preferred type of elastomer are thermoplastic elastomers having functional or polar groups, such as carboxylic acid, maleic anhydride, glycidyl, norbonene, and hydroxyl group. Examples are maleic anhydride functionalized triblock copolymer consisting of polystyrene end blocks and poly(ethylene/butylene) such as Kraton FG 1901X by Shell

Chemical Co.; maleic anhydride modified ethylene- vinyl acetate copolymer such as Fusabond by Du Pont; ethylene-ethyl acrylate-maleic anhydride terpolymer such as Bondine AX 8390 by Sumitomo Chemical Industries Co. Ltd.; ethylene-ethyl acrylate-maleic anhydride terpolymer such as Bondine AX8060 by Sumitomo; brominated styrene-isobutylene copolymers such as Bromo XP-50, by Exxon; Lotader resins with glycidyl or maleic anhydride functional group by

Elf Atochem; ethylene-isobutyl acrylate-methacrylic acid terpolymer such as Nucrel by Du Pont and the mixtures of the above resins. Another preferred type of elastomer are the olefinic thermoplastic elastomers, such. as blends of polyolefins with ethyl-propylene-nonconjugated diene terpolymer, block copolymers of styrene and butadiene, or isoprene or ethylene-butylene elastomer. Examples of such resins are those sold under the names Santoprene, Dytron, Vistaflex, Sarlink, and Vyram, which are dynamically vulcanized thermoplastic elastomers.

Yet another preferred type of elastomer are the polyurethanes, including thermosets as well as thermoplastic polyurethanes. Examples of thermoplastic polyurethane resins are sold under the name Estane resin, such as Estane 58133, Estane 58134, and Estane 58144, Estane 58285 produced by B. F. Goodrich Co. Another preferred material for inclusion in the base material is ionomer which can be described as copolymer E/X/Y, where E represents ethylene, X represents a softening comonomer, and Y is acrylic or methacrylic acid. The acid moiety of Y is neutralized by a cation such as lithium, sodium, potassium, magnesium, calcium, barium, lead, zinc or aluminum. Also a combination of such cations are use for the neutralization. Preferred ionomers are the copolymers of α-olefin and unsaturated carboxylic acid, preferably, α,β- unsaturated carboxylic acids, whose acidic functions are partially neutralized by a metal ion.

Appropriate alpha-olefins for use in preparing ionomers include ethylene, propylene, 1- butene, and 1-hexene. Suitable unsaturated carboxylic acids include acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid.

The alkyl group of the alkyl methacrylate may comprise up to 18 carbon atoms. Preferred alkyl methacrylates include methyl, ethyl, n-butyl, and isobutyl methacrylate. Preferably the alkyl methacrylate resins have a flexural modulus of about 500-150,000 psi (ASTM D-790), a hardness of about 20-80 shore D (ASTM D-2240), and a melt flow index of about 0.2-10 g/lOmin (ASTM D-1238).

Acid ionomers may be classified as either high acid ionomers or low acid ionomers, wherein the high acid ionomers comprise at least 16% by weight carboxylic acid, preferably 18- 19%) by weight of carboxylic acid. The carboxylic acid is preferably unsaturated, more preferably α,β unsaturated. The low acid ionomers comprise less than 16% carboxylic acid by weight. Preferably the low acid ionomers used in the compositions of the present invention will have a flexural modulus less than about 60,000 psi (ASTM D-790) and the high acid ionomers will preferably have a flexural modulus greater than 60,000 psi. The high acid ionomers preferably have a hardness of at least about 65 shore D. Examples of high acid ionomers include those sold under the name Surlyn by E_^ I. DuPont de Nemours and Co, and the Exxon Co. resins sold under the names Iotek and Escor. These resins are available in a number of grades, for example the Surlyn resins are available as Surlyn 9120, 8140, AD8546 and AD8552. Any of these resins alone, or any combinations thereof, are suitable for use in the golf ball cover compositions of the present invention.

Yet another preferred material that the base material may comprise is polyamide. Polyamides are polymers containing amide groups, -CO-NH-, in the structure which are products of the condensation polymerization of a diacid and a diamine. Polyamides are also prepared from lactams by ring opening reaction. The polyamides; can be linear, semi-crystalline, or aromatic polyamides and/or their blends. For example, there are different types of polyamide resins, such as type 6, 11, 12, 46, 66, 610, 612, 6/66 sold under the name Ashlene by Ashley Polymers; Capron by AlliedSignal; Durathan by Bayer; Grilamid by EMS- America; Rilsan by Elf Atochem; Ube by Ube Industries; Ultramid by BASF; Vestamid by Creanova Inc.; and Zytel by Du Pont. Other preferred material for inclusion in the base material are polyesters and polycarbonates. Polyesters are polymers prepared either from a hydroxy acid or from a dialcohol and a diacid. Examples of thermoplastic polyesters are polyethylene terephthalate, polybutyleneterephthalate. Examples of polyesters and polycarbonates are sold under the names Valox and Lexan by GE Plastics, and come in a variety of grades. To make a composition of the present invention, the base material and the organometallic compounds are mixed together. The organometallic compounds can be in any form which allows for mixing and measuring, including liquid, liquid diluted with a solvent, powder, or in a pellet form. The quantity of active organometallic compounds used is preferably in the range of 0.01 - 20 phr (parts by weight per hundred parts of base material by weight), more preferably it is in the range of 0.1 - 10 phr, most preferably in the range of 0.2 -

5 phr. Here, "active organometallic compounds" means the organometallic compounds only, without any carrying agent, solvent, powder or polymeric binder which may be present. The composition of the invention can also include, in suitable amounts, one or more additional ingredients generally employed in golf ball cover or mantle compositions. Agents provided to achieve specific functions, such as additives, stabilizers, and reinforcing materials such as organic fibers and/or inorganic fibers can be present. Ingredients which are suitable include UV stabilizers, photo stabilizers, antioxidants, pigments, dispersants, mold release agent, and processing aids. Examples of fillers include one or more organic or inorganic fillers. For example, inorganic fillers can be added such as titanium dioxide (TiO₂), calcium carbonate, zinc sulfide, zinc oxide, or glass beads. Additional fillers, such as zinc oxide, barium sulfate, tungsten carbite, or lead powder, can be chosen to impart additional density to blends.

Once the components are chosen and the quantities for use measured, the composition of the present invention can be blended by an apparatus capable of mixing materials such as a dry mixer, Banbury type mixer, two-roll mill, or single screw or twin screw extruder.

The compositions of the present invention may be formed into golf ball covers or mantles by conventional techniques as are known in the art. The cover may be placed directly over the core of the ball to form a two-piece ball, or it may be used for covering the core which itself is already covered with an intermediate layer or layers of mantle materials to form a three-piece golf ball.

One technique known in the art is injection molding. In this technique, the cover can be directly applied by injection molding over a core or mantle layer or layers. The inner portion of the ball, comprising a core, mantle, or both, is placed into a mold and a melt of the cover material is injected into the mold. The melt of cover material fills the mold, surrounding the core or mantle and taking its shape from the shape of the mold. When the cover material has cooled sufficiently as not to be damaged by handling, the mold is opened and the newly formed golf ball is removed.

Another method comprises forming the material into half-cups, preferably by injection molding into a half-shell mold, positioning the two half-cups around the core or the mantle in a conventional compression molding device, and then applying pressure and heat for a predetermined time to allow the two halves to unite to form a single cover. The ball is allowed to cool in the mold until the cover is hard and solid enough to be removed from the mold without deforming. In the case of a wound mantle or core, this method is preferred over injection molding because the heat of the injection molding around a wound core or mantle may cause the thread to snap during molding.

Mantles may be made by an injection molding process whereby the mantle material of the present invention is injected into a mold over a core. The mantle is later topped with a cover. Mantles may also be made by the compression molding technique, as described above. In either case, the mantle may cover a core or the mantle may be assembled or molded, filled with a liquid, and then sealed or plugged before placing the cover over the mantle.

Once the cover is made the golf ball undergoes other operations such as buffing, painting, and stamping. In order to facilitate the buffing, the golf ball can be pre-frozen. Testing and Results

A composition of the present invention was tested in the form of a golf ball cover. The composition tested comprised 0.5 phr Capow LICA 97 (neopentyl(diallyl)oxy, tri(m- amino)phenyl titanate, Kenrich Petrochemicals) in Pebax 1205 (copolyetheramide, Elf

Atochem). Quantities of Pebax 1205 and LICA 97 were weighed according to the formulation and dry blended in a tumbler mixer for 30 minutes at room temperature. The batch of dry blended resins were then compounded by a 35 mm twin screw extruder. The processing conditions were as follows: from the feeder to die, TI = 80°C, T2 = 185°C, T3 = 205°C, T4 = 210°C, T5 = 210°C, T6 = 195°C, Tdie = 195°C, and screw speed = 150 rpm. The extruded resins were made into a golf ball cover by injection molding. Control golf balls having Pebax 1205 covers (without organometallic) were also made. The control golf balls and the golf balls of the present invention were three-piece golf balls and had the same core and mantle materials. Two types of commercially available balls, one having a synthetic balata cover and one having a cover made of Surlyn ionomer, completed the set of test balls.

To test the cut resistance of the covers, a shear test was done on the set of test balls above. In the test, two golf balls of each cover composition were shot twice at 80 mph with a Taylor Made Tour 55 sand wedge type club having the following physical characteristics: lie: 64°; loft: 55°; bounce: 8°; club length: 35 inches. A visual evaluation was made, and each ball was given a score from 1 to 5, depending on the degree of damage to the ball. The criteria for the scores were as follows: 1 = excellent (no paint or cover damage); 2 = good (paint damage only); 3 = average (minor cover damage); 4 = fair (moderate cover damage, slight material removed); 5 = poor (major cover damage, moderate material removed). An average was taken of the scores for each golf ball cover composition to get a final score for that composition. These results appear in Table 1 below.

To test the durability of the golf ball covers, a test was done to simulate the effect of being struck repeatedly with a driver. In the durability test, the set of test golf balls were fired out of the cylinder of a testing machine of the type used for conventional coefficient of restitution testing. The set of test golf balls (12 of each) were conditioned at room temperature for a period of two weeks prior to the test. The balls were fired out of the cylinder at 125 ft/sec onto a stationary steel plate, and periodically checked for cracks. The test for each set of 12 balls consisted of up to 5 cycles of 50 hits(firings) for each ball in the set. The test for a set of balls ceased when 50% of the balls in the set had crack failures (50% failure). If 50% failure was not reached, the test was stopped after 5 cycles (250 hits). The number of hits for the first failure and the number of hits for the 50%> failure are recorded for each set of test balls. The results of this test are shown in Table 1.

TABLE 1

It can be seen from the data in Table 1 that the addition of a small quantity of an organometallic compound to the elastomeric base material results in a substantial difference in the durability and shear resistance of the golf ball cover. Addition of a small amount of organometallic compound resulted in a shear resistance that was "good" compared to "poor" for the control ball. Additionally, none of the inventive balls tested experienced a crack failure in the durability test after as many as 250 hits, compared to the 50%> failure at 195 hits found for the control balls. Furthermore, the increase in durability and shear resistance was not achieved at the expense of the coefficient of restitution, which translates into good speed when leaving the club head. Although the present invention has been described in terms of certain preferred embodiments, it is to be understood that the scope of the invention is not to be limited thereby. Instead, the inventor intends that the scope of the invention be limited solely by reference to the attached claims, and that variations on the materials and formulations disclosed herein which are apparent to those of skill in the art will fall within the scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A golf ball cover or mantle comprising a composition formed into said golf ball cover or mantle, said composition comprising:

100 parts by weight of base material, wherein said base material is a homopolymer, copolymer, terpolymer or blend of resins selected from the group consisting of copolyetherester elastomers, copolyetherester elastomers, copolyetheramide elastomers, styrenic copolymers, thermoplastic elastomers having a polar group, olefmic elastomers, polyurethanes, ionomers, polyamides, and polyesters; and 0.01 -20 phr of at least one organometallic compound.

2. The golf ball cover or mantle of Claim 1, wherein said composition comprises 0.1-10 phr of at least one organometallic compound.

3. The golf ball cover or mantle of Claim 1, wherein said composition comprises 0.2-5 phr of at least one organometallic compound.

4. The golf ball cover or mantle of Claim 1 , wherein said organometallic compound is selected from the group consisting of titanates, zirconates, and aluminates.

5. The golf ball cover or mantle of Claim 1, wherein said organometallic compound is a neoalkoxy titanate.

6. The golf ball cover or mantle of Claim 1, wherein said organometallic compound is a neoalkoxy zirconate.

7. The golf ball cover or mantle of Claim 1, wherein said base material comprises copolyetheramide.

8. The golf ball cover or mantle of Claim 1, wherein said base material comprises copolyetherester.

9. A golf ball comprising a core; and a cover, wherein said cover comprises 100 parts by weight of base material, wherein said base material is a homopolymer, copolymer, or blend of resins selected from the group consisting of elastomers, copolyetherester elastomers, copolyetheramide elastomers, styrenic copolymers, thermoplastic elastomers having a polar group, olefmic elastomers, polyurethanes, ionomers, polyamides, and polyesters; and 0.01-20 phr of at least one organometallic compound.

10. The golf ball of Claim 9, further comprising a mantle.

11. The golf ball of Claim 10, wherein said mantle comprises 100 parts by weight-of base material, wherein said base material is a homopolymer, copolymer, or blend of resins selected from the group consisting of elastomers, copolyetherester elastomers, copolyetheramide elastomers, styrenic copolymers, thermoplastic elastomers having a polar group, olefmic elastomers, polyurethanes, ionomers, polyamides, and polyesters; and 0.01-20 phr of at least one organometallic compound.

12. The golf ball of Claim 10, wherein said mantle comprises wound thread.

13. The golf ball of Claim 12, wherein said core comprises liquid or paste.

14. The golf ball of Claim 9, wherein said cover comprises 0.1-10 phr of at least one organometallic compound.

15. The golf ball of Claim 9, wherein said cover comprises 0.2-5 phr of at least one organometallic compound.

16. The golf ball of Claim 9, wherein said organometallic compound is selected from the group consisting of titanates, zirconates, and aluminates.

17. The golf ball of Claim 9, wherein said organometallic compound is a neoalkoxy titanate.

18. The golf ball of Claim 9, wherein said organometallic compound is a neoalkoxy zirconate.

19. The golf ball of Claim 9, wherein said base material comprises copolyetheramide.

20. The golf ball of Claim 9, wherein said base material comprises copolyetherester.

21. A method of making a golf ball cover or mantle, comprising the steps of: combining 100 parts by weight of base material, wherein said base material is a homopolymer, copolymer, or blend of resins selected from the group consisting of elastomers, copolyetherester elastomers, copolyetheramide elastomers, styrenic copolymers, thermoplastic elastomers having a polar group, olefmic elastomers, polyurethanes, ionomers, polyamides, and polyesters with 0.01-20 phr of at least one organometallic compound to form a composition; mixing said composition; and molding said composition to form a golf ball cover or mantle.

22. The method of Claim 21, wherein said composition comprises 0.1-10 phr of at least one organometallic compound.

23. The method of Claim 21, wherein said composition comprises 0.2-5 phr of-at least one organometallic compound.

24. The method of Claim 21, wherein said organometallic compound is selected from the group consisting of titanates, zirconates, and aluminates.

25. The method of Claim 21, wherein said organometallic compound is a neoalkoxy titanate.

26. The method of Claim 21, wherein said organometallic compound is a neoalkoxy zirconate.

27. The method of Claim 21, wherein said base material comprises copolyetheramide.

28. The method of Claim 21 , wherein said base material comprises copolyetherester.