Golf balls comprising functionalized polyurethane compositions   

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to golf balls containing at least one layer made from a composition comprising a functionalized thermoplastic or thermoset polyurethane having ionomer or ionomer precursor moieties such as acids or esters. More particularly, the layer contains a functionalized polytrimethylene ether-based polyurethane produced from a reaction of polyisocyanate with polytrimethylene ether glycol or blends of polytrimethylene ether glycol with other glycols such as polyester glycol, polycaprolactone glycol, or polycarbonate glycol; and a curing agent. At least one of the reactive components contains acid or ester or ionic groups. The composition may be used to form any layer in the golf ball structure such as, for example, an outer core, intermediate layer, inner cover, and/or outer cover. The resulting golf ball has improved physical properties.

2. Brief Review of the Related Art

Multi-piece solid golf balls having an inner core and outer cover with an intermediate layer disposed there between are popular today in the golf industry. The inner core is made commonly of a rubber material such as natural and synthetic rubbers, styrene butadiene, polybutadiene, poly(cis-isoprene), or poly(trans-isoprene). Often, the intermediate layer is made of an olefin-based ionomer resin that imparts hardness to the ball. These ionomer acid copolymers contain inter-chain ionic bonding, and are generally made of an α-olefin such as ethylene and a vinyl comonomer having an acid group such as methacrylic, acrylic acid, or maleic acid. Metal ions such as sodium, lithium, zinc, and magnesium are used to neutralize the acid groups in the copolymer. Commercially available olefin-based ionomer resins are used in different industries and include numerous resins sold under the trademarks, Surlyn® (available from DuPont) and Escor® and Iotek® (available from ExxonMobil), Amplify IO® (available from Dow Chemical) and Clarix® (available from A. Schulman). Olefin-based ionomer resins are available in various grades and identified based on the type of base resin, molecular weight, and type of metal ion, amount of acid, degree of neutralization, additives, and other properties. The outer cover of conventional golf balls are made from a variety of materials including olefin-based ionomers, polyamides, polyesters, and thermoplastic and thermoset polyurethane and polyurea elastomers.

In recent years, there has been substantial interest in using thermoset, castable polyurethanes and polyureas to make core, intermediate, and/or cover layers for the golf balls. Basically, polyurethane compositions contain urethane linkages formed by reacting an isocyanate group (—N═C═O) with a hydroxyl group (OH). Polyurethanes are produced by the reaction of a polyisocyanate with a polyol in the presence of a catalyst and other additives. The chain length of the polyurethane prepolymer is extended by reacting it with a hydroxyl-terminated curing agent. Polyurea compositions, which are distinct from the above-described polyurethanes, also can be formed. In general, polyurea compositions contain urea linkages formed by reacting an isocyanate group (—N═C═O) with an amine group (NH or NH2). The chain length of the polyurea prepolymer is extended by reacting the prepolymer with an amine curing agent. Hybrid compositions containing urethane and urea linkages also may be produced. For example, a polyurethane/urea hybrid composition may be produced when a polyurethane prepolymer is reacted with an amine-terminated curing agent as discussed further below.

Golf balls made with polyurethane and polyurea materials are generally described in the patent literature, for example, U.S. Pat. Nos. 5,334,673; 6,476,176; 6,506,851; 6,867,279; 6,960,630; and 7,105,623. In particular, polyurethane ionomers are disclosed in U.S. Pat. Nos. 6,193,207,784; 6,207,784; and 6,610,812 but these patents do not teach the use of functionalized polytrimethylene based compositions having acid, ester, or ionic moieties.

As discussed above, in general, isocyanate compounds with two or more functional groups are reacted with polyols to form the polyurethane compositions. There are various isocyanates and polyols used to manufacture polyurethanes. For example, it is known that polyurethanes can be prepared using polytrimethylene ether glycols. For example, Sunkara, U.S. Pat. Nos. 6,852,823; 6,946,539; and 7,244,810; and U.S. Patent Application Publication Nos. US 2007/0129524 and US 2008/0039582 disclose polytrimethylene ether-based thermoplastic polyurethane and polyurethane-urea compositions and their ionomers prepared from: a) poly(trimethylene-ether) glycol; b) diisocyanate; and c) diol or diamine chain extender. These patent documents disclose that the compositions may be used for breathable membranes, synthetic lubricants, hydraulic fluids, cutting oils, motor oils, surfactants, spin-finishes, water-borne coatings, laminates, adhesives, packaging, films and foams, fibers and fabrics. Sunkara et al., U.S. Patent Application Publication No. US 2005/0256294 disclose using polytrimethylene ether glycol-based polyurethanes in one or more layers of a golf ball; however, there is no disclosure of using polyurethane ionomer or ionomer precursors in golf balls.

There continues to be interest in developing multi-layered golf balls containing components or layers that impart high resiliency to the balls. In general, golf balls having a higher resiliency tend to have higher initial velocity and retain more total energy when struck with a club. This allows players to achieve longer flight distances when hitting the ball off the tee. In addition, the balls should have relatively high cut/tear-resistance and impact durability. This helps the balls appear relatively new even after repeated use. Such balls generally do not cut, tear, or otherwise damage easily. At the same time, the golf ball should have a relatively soft feel. In general, golfers experience a more natural and pleasant feeling when striking such soft feel golf balls with the club face. The player senses more control and softer ball covers tend to provide higher initial spin. This is particularly advantageous to players making approach shots near the green.

Golf balls made of new polyurethane ionomer or ionomer precursor compositions are particularly desirable, because they can help provide a highly resilient ball with good impact durability and toughness as well as optimum playing performance properties such as feel, softness, spin control, and the like. The present invention provides methods for making such golf balls and the resultant balls.

SUMMARY

The present invention relates to multi-layered golf balls made from a composition comprising a thermoplastic or thermoset polyurethane ionomer or ionomer precursor. The composition may be used to form any layer in the golf ball structure such as, for example, an outer core, intermediate layer, inner cover, and/or outer cover. The golf balls made of the compositions of this invention are highly resilient and have good impact durability and toughness. Moreover, the ball has a soft feel and optimum playing performance properties.

In one preferred embodiment, the ball includes a core which can be made of polybutadiene, highly neutralized polymer, or other suitable material. The core preferably has Shore D surface hardness (H1) in the range of about 10 to about 60. An intermediate layer surrounds the core and is formed from a functionalized polytrimethylene ether-based polyurethane or polyurethane/polyurea hybrid composition. This is the reaction product of: i) an isocyanate compound, ii) a polytrimethylene ether glycol compound (or blends of polytrimethylene ether glycol with other glycols such as polyester glycol, polycaprolactone glycol, or polycarbonate glycol), and iii) a curing agent selected from the group consisting of hydroxyl-terminated curing agents, amine-terminated curing agents, and mixtures thereof, wherein at least one of the isocyanate compound, polytrimethylene ether glycol compound, or curing agent contains acid, ester, or ionic groups. The intermediate layer preferably has a thickness in the range of about 0.010 to about 0.040 inches and a Shore D surface hardness (H2) in the range of about 30 to about 75 and more preferably 50 to 75. A cover layer, which may be formed from conventional materials such as olefin-based ionomers, polyurethanes, polyureas, polyesters, polyamide-ester elastomers, surrounds the intermediate layer. The cover layer has a Shore D surface hardness (H3) in the range of about 30 to about 60. The ratio of H3 to H1 is in the range of about 0.6 to about 6.

In a second preferred embodiment, the ball includes a core having a Shore D surface hardness (H1) in the range of about 10 to about 60 and an intermediate layer having a Shore D surface hardness (H2) in the range of about 50 to about 75. There is a cover layer having a Shore D surface hardness (H3) in the range of about 45 to about 65 and a thickness in the range of about 0.010 to about 0.030 inches. The cover layer is formed from the functionalized polytrimethylene ether-based polyurethane or polyurethane/polyurea hybrid composition as described above.

In a third preferred embodiment, the ball includes a dual core having inner and outer core layers. The outer core has a thickness in the range of about 0.030 to about 0.070 inches and a Shore D surface hardness in the range of about 40 to about 70. An intermediate layer having a thickness in the range of about 0.010 to about 0.040 inches and a Shore D surface hardness in the range of about 50 to about 75 surrounds the outer core. A cover layer having a thickness in the range of about 0.010 to about 0.030 inches and a Shore D surface hardness in the range of about 45 to about 65 surrounds the intermediate layer. At least one of the outer core, intermediate, or cover layers is formed from the functionalized polytrimethylene ether-based polyurethane or polyurethane/polyurea hybrid composition as described above.

In a fourth preferred embodiment, the ball includes a triple-layered cover. The ball includes a core and a triple-layered cover surrounding the core. The innermost cover layer. overlying the core, has a Shore D surface hardness in the range of about 50 to about 75. Additionally, there are intermediate and outer cover layers. At least one of the innermost, intermediate, or outer cover layers is formed from a functionalized polytrimethylene ether-based polyurethane or polyurethane/polyurea hybrid composition as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features that are characteristic of the present invention are set forth in the appended claims. However, the preferred embodiments of the invention, together with further objects and attendant advantages, are best understood by reference to the following detailed description in connection with the accompanying drawings in which:

FIG. 1 is a front view of a dimpled golf ball made in accordance with the present invention;

FIG. 2 is a cross-sectional view of a multi-layered (three-piece) golf ball having an intermediate layer made of a functionalized polytrimethylene ether-based polyurethane acid, ester, or ionomer composition in accordance with the present invention;

FIG. 3 is a cross-sectional view of a multi-layered (four-piece) golf ball having an outer core layer made of a functionalized polytrimethylene ether-based polyurethane acid, ester, or ionomer composition in accordance with the present invention;

FIG. 4 is a cross-sectional view of a multi-layered (four-piece) golf ball having an inner cover layer made of a functionalized polytrimethylene ether-based polyurethane acid, ester, or ionomer composition in accordance with the present invention; and

FIG. 5 is a cross-sectional view of a multi-layered (four-piece) golf ball having a multi-layered core, intermediate layer, and outer cover layer made in accordance with the present invention

DETAILED DESCRIPTION

The present invention relates generally to golf balls containing at least one “layer” made from a polytrimethylene ether-based polyurethane acid, ester, or ionomer. The term, “layer” as used herein means generally any spherical portion of a golf ball. The polytrimethylene ether-based polyurethane acid, ester, or ionomer composition of this invention may be used to form any layer in the golf ball structure including, but not limited to, an outer cover, inner cover, intermediate layer, and/or outer core layer.

In general, polyurethane compositions contain urethane linkages formed by reacting an isocyanate group (—N═C═O) with a hydroxyl group (OH). Commercial polyurethanes are produced by the reaction of a polyisocyanate with a polyalcohol (polyol) in the presence of a catalyst and other additives. The chain length of the polyurethane prepolymer is extended by reacting it with a hydroxyl-terminated curing agent. The resulting polyurethane polymer has elastomeric properties based on phase separation of its soft and hard segments. The soft segments, which are formed from the polyols, are generally flexible, while the hard segments, which are formed from the isocyanate and chain extenders, are generally stiff

In the present invention, a functionalized polytrimethylene ether-based polyurethane or polyurethane/urea hybrid composition is produced by a reaction of an isocyanate compound, a polytrimethylene-ether glycol compound, and a hydroxyl or amine curing agent. At least one of the reactive components contains acid, ester, or ionic groups. If the reactive component contains acid or ester groups, then a polytrimethylene ether-based polyurethane (or polyurethane/urea hybrid) ionomer precursor is formed. On the other hand, if the reactive component contains ionic groups, then a polytrimethylene ether-based polyurethane (or polyurethane/urea hybrid) ionomer is formed. By the term, “polytrimethylene ether-based polyurethane and polyurethane/urea hybrid compositions” it is meant a functionalized polytrimethylene ether-based polyurethane or polyurethane/urea hybrid composition, unless otherwise specifically stated herein.

Isocyanate Compounds

Any suitable isocyanate known in the art can be used to produce the polyurethane composition in accordance with this invention. Such isocyanates include, for example, aliphatic, cycloaliphatic, aromatic aliphatic, aromatic, any derivatives thereof, and combinations of these compounds having two or more isocyanate (—N═C═O) groups per molecule. The isocyanates may be organic polyisocyanate-terminated prepolymers, isocyanate prepolymers having a low residual amount of unreacted isocyanate monomer (“low free” isocyanates), and mixtures thereof The isocyanate-containing reactable component also may include any isocyanate-functional monomer, dimer, trimer, or polymeric adduct thereof, prepolymer, quasi-prepolymer, or mixtures thereof Isocyanate-functional compounds may include monoisocyanates or polyisocyanates that include any isocyanate functionality of two or more.

Preferred isocyanates include diisocyanates (having two NCO groups per molecule), biurets thereof, dimerized uretdiones thereof, trimerized isocyanurates thereof, and polyfunctional isocyanates such as monomeric triisocyanates. Diisocyanates typically have the generic structure of OCN—R—NCO. Exemplary diisocyanates include, but are not limited to, unsaturated isocyanates such as: p-phenylene diisocyanate (“PPDI,” i.e., 1,4-phenylene diisocyanate), m-phenylene diisocyanate (“MPDI,” i.e., 1,3-phenylene diisocyanate), o-phenylene diisocyanate (i.e., 1,2-phenylene diisocyanate), 4-chloro-1,3-phenylene diisocyanate, toluene diisocyanate (“TDI”), m-tetramethylxylene diisocyanate (“m-TMXDI”), p-tetramethylxylene diisocyanate (“p-TMXDI”), 1,2-, 1,3-, and 1,4-xylene diisocyanates, 2,2′-, 2,4′-, and 4,4′-biphenylene diisocyanates, 3,3′-dimethyl-4,4′-biphenylene diisocyanate (“TODI”), 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanates (“MDI”), 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, carbodiimide-modified MDI, polyphenylene polymethylene polyisocyanate (“PMDI,” i.e., polymeric MDI), 1,5-naphthalene diisocyanate (“NDI”), 1,5-tetrahydronaphththalene diisocyanate, anthracene diisocyanate, tetracene diisocyanate; and saturated isocyanates such as: 1,4-tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, 1,6-hexamethylene diisocyanate (“HDI”) and isomers thereof, 2,2,4- and 2,4,4-trimethylhexamethylene diisocyanates, 1,7-heptamethylene diisocyanate and isomers thereof, 1,8-octamethylene diisocyanate and isomers thereof, 1,9-nonamethylene diisocyanate and isomers thereof, 1,10-decamethylene diisocyanate and isomers thereof, 1,12-dodecane diisocyanate and isomer thereof, 1,3-cyclobutane diisocyanate, 1,2-, 1,3-, and 1,4-cyclohexane diisocyanates, 2,4- and 2,6-methylcyclohexane diisocyanates, isophorone diisocyanate (“IPDI”), isocyanatomethylcyclohexane isocyanate, isocyanatoethylcyclohexane isocyanate, 4,4′-dicyclohexylmethane diisocyanate (“H12 MDI,” i.e., bis(4-isocyanatocyclohexyl)-methane), and 2,4′- and 4,4′-dicyclohexane diisocyanates. Dimerized uretdiones of diisocyanates and polyisocyanates include, for example, unsaturated isocyanates such as uretdiones of toluene diisocyanates, uretdiones of diphenylmethane diisocyanates; and saturated isocyanates such as uretdiones of hexamethylene diisocyanates. Trimerized isocyanurates of diisocyanates and polyisocyanates include, for example, unsaturated isocyanates such as trimers of diphenylmethane diisocyanate, trimers of tetramethylxylene diisocyanate, isocyanurates of toluene diisocyanates; and saturated isocyanates such as isocyanurates of isophorone diisocyanate, isocyanurates of hexamethylene diisocyanate, isocyanurates of trimethyl-hexamethylene diisocyanates. Monomeric triisocyanates include, for example, unsaturated isocyanates such as 2,4,4′-diphenylene triisocyanate, 2,4,4′-diphenylmethane triisocyanate, 4,4′,4″-triphenylmethane triisocyanate; and saturated isocyanates such as: 1,3,5-cyclohexane triisocyanate. Preferably, the isocyanate is selected from the group consisting of MDI, H12MDI, PPDI, TDI, IPDI, HDI, NDI, XDI, TMXDI, THDI (trimerized HDI), and TMDI (trimerized MDI), and homopolymers and copolymers and mixtures thereof.

Polyol Compounds

As discussed above, a polyurethane composition is generally an elastomeric material that is the reaction product of isocyanate and hydroxyl components. There are many polyol compounds known in the art. Surprisingly, it has been found that a polyol component selected from polytrimethylene ether glycol and blends of polytrimethylene ether glycol with other glycols such as polyester glycol, polycaprolactone glycol, or acid or ionic functionalized glycols provides a polyurethane composition having many advantageous properties for purposes of this invention. The resulting functionalized polytrimethylene ether-based polyurethane composition can be used to manufacture golf balls having an optimum combination of “resiliency” and “softer feel” properties. The combination of the polytrimethylene ether-based polyurethane and other materials comprising the core, intermediate layer and/or cover layer provides a finished ball that can be used to achieve increased distance. And yet, the golf ball retains a relatively soft feel. Thus, players can more easily control the play of the ball.

By the term, “polytrimethylene ether glycol” (“PO3G”), as used herein, it is meant oligomers and polymers in which at least about 50% of the repeating units are trimethylene ether units —(CH2—CH2—CH2—O—). More preferably from about 75% to 100%, still more preferably from about 90% to 100%, and even more preferably from about 99% to 100%, of the repeating units are trimethylene ether units. Such PO3G compounds and the methods for making such compounds are described in the above-mentioned patent application, Sunkara et al., U.S. Patent Application Publication 2008/0039582, the disclosure of which is hereby incorporated by reference. The PO3G compounds are preferably prepared by polycondensation of monomers comprising 1,3-propanediol, thus resulting in polymers or copolymers containing —(CH2CH2CH2O)— linkages (e.g, trimethylene ether repeating units). The 1,3-propanediol employed for preparing the PO3G may be obtained by any of the various well known chemical routes or by biochemical transformation routes. Preferably, the 1,3-propanediol is obtained biochemically from a renewable source (“biologically-derived” 1,3-propanediol).

The compounds of this invention based on polytrimethylene ether glycols, may contain lesser amounts of other polyalkylene ether repeating units in addition to the trimethylene ether units. The monomers for use in preparing polytrimethylene ether glycols can, therefore, contain up to 50% by weight (preferably about 20 wt or less, more preferably about 10 wt % or less, and still more preferably about 2 wt % or less), of comonomer polyols in addition to the 1,3-propanediol reactant. Comonomer polyols that are suitable for use in the process include aliphatic diols, for example, ethylene glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 3,3,4,4,5,5-hexafluro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-hexanediol, and 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexadecafluoro-1,12-dodecanediol; cycloaliphatic diols, for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and isosorbide; and polyhydroxy compounds, for example, glycerol, trimethylolpropane, and pentaerythritol. A preferred group of comonomer diols is selected from the group consisting of ethylene glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, C6-C10 diols (such as 1,6-hexanediol, 1,8-octanediol and 1,10-decanediol) and isosorbide, and mixtures thereof. A particularly preferred diol other than 1,3-propanediol is ethylene glycol, and C6-C10 diols can be particularly useful as well. In another embodiment of the present invention further comprises polytrimethylene ether ester glycols by reacting 1,3-propanediol with about 10 to about 0.1 mole % of aliphatic or aromatic diacid or esters thereof, such as terephthalic acid, isophthalic acid, bibenzoic acid, naphthalic acid, bis(p-carboxyphenyl)methane, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4′-sulfonyl dibenzoic acid, p-(hydroxyethoxy)benzoic acid, and combinations thereof, and dimethyl terephthalate, bibenzoate, isophthlate, naphthalate and phthalate; and combinations thereof. Of these, terephthalic acid, dimethyl terephthalate and dimethyl isophthalate are preferred.

The preferred polytrimethylene ether glycol and blends of polytrimethylene ether glycol compounds preferably have a number average molecular weight (Mn) in the range of about 200 to about 5000, and more preferably from about 500 to about 5000. The compounds may be blended with other oligomeric and/or polymer polyfunctional isocyanate-reactive compounds such as, for example, polyols, polyamines, polythiols, polythioamines, polyhydroxythiols and polyhydroxylamines. When blended, it is preferred to use difunctional components and, more preferably, one or more diols including, for example, polyether diols, polyester diols, polycarbonate diols, polyacrylate diols, polyolefin diols and silicone diols. The polytrimethylene ether glycol compounds contain at least about 40% PO3G and preferably about 60% PO3G. That is, the PO3G may be blended with up to about 60% polyfunctional oligomeric and/or polymeric polyfunctional isocyanate-reactive compounds. Preferably, the blended compounds are a blend of polytrimethylene ether glycol and a polyether glycol selected from the group consisting of polyethylene glycol, poly(1,3-propylene)glycol, polytetramethylene glycol, copolymers of tetrahydrofuran and ethylene oxide or propylene oxide glycol, and mixtures there of.

In the present invention, it is important that the polytrimethylene ether-based polyurethane contains acid or ester or ionic groups. That is, the polyurethane composition is preferably prepared from: i) an isocyanate compound, ii) a polytrimethylene ether glycol compound, and iii) a curing agent selected from the group consisting of hydroxyl-terminated curing agents, amine-terminated curing agents, and mixtures thereof. At least one of the reactive components contains acid or ester or ionic groups. The acid or ionic groups are chemically incorporated into the polytrimethylene ether-based polyurethane in an amount to provide an acid or ester or ionic content (with neutralization as needed) sufficient to render improved resiliency and good impact durability to the resulting golf ball without sacrificing a soft feel and playing control to the ball. Typically, the acid group content will range from about 0.5 to about 50 wt %, more preferably from about 2.5 to 45 wt %, and still more preferably from about 5 to 30 wt % based on the weight of the polytrimethylene-ether based polyurethane. Suitable compounds for incorporating these groups include (1) monoisocyanates or diisocyanates which contain acid, ester, or ionic groups, and (2) compounds which contain both isocyanate reactive groups and acid, ester, or ionic groups.

Examples of isocyanates that contain acid or ionic groups are sulfonated toluene diisocyanate and sulfonated diphenylmethanediisocyanate. With respect to compounds which contain isocyanate reactive groups and acid, ester, or ionic groups, the isocyanate reactive groups are typically amino and hydroxyl groups. The acid or their corresponding ionic groups may be cationic or anionic, although the anionic groups are preferred. Preferred examples of anionic groups include carboxylate and sulfonate groups. Preferred examples of cationic groups include quaternary ammonium groups and sulfonium groups. The term “neutralizing agents” is meant to include all types of agents that are useful for converting acid groups to the more hydrophilic ionic (salt) groups.

More particularly, the isocyanate reactant contains acid or ionic groups). Preferably, these reactants will contain one or two, more preferably two, isocyanate reactive groups, as well as at least one acid or ionic group. Examples of ionic dispersing groups include carboxylate groups (—COOM), phosphate groups (—OPO3 M2), phosphonate groups (—PO3M2), sulfonate groups (—SO3M), quaternary ammonium groups (—NR3Y, wherein Y is a monovalent anion such as chlorine or hydroxyl), or any other effective ionic group. M is a cation such as a mono-valent metal ion (e.g., Na+, K+, Li.+, and the like.), H+, NR4.+, and each R can be independently an alkyl, aralkyl, aryl, or hydrogen. These ionic dispersing groups are typically located pendant from the polyurethane backbone.

The acid groups in general correspond to the ionic groups, except they are in the acid (such as carboxyl —COOH) or base (such as primary, secondary or tertiary amine —NH2, —NRH, or —NR2) form. The acid groups are such that they are readily converted to their ionic form during the polymer preparation process as discussed below.

Manufacturing Processes

There are two basic techniques that can be used to make the functionalized polytrimethylene ether-based polyurethane compositions of this invention: a) one-shot technique, and b) prepolymer technique. In the one-shot technique, the isocyanate, polytrimethylene ether glycol, and hydroxyl and/or amine-terminated curing agent are reacted in one step. At least one of the reactive components contains acid, ester, or ionic groups. Meanwhile, the prepolymer technique involves a first reaction between the isocyanate and polytrimethylene ether glycol compounds to produce a polyurethane prepolymer, and a subsequent reaction between the prepolymer and hydroxyl and/or amine-terminated curing agent. As a result of the reaction between the isocyanate and polyol compounds, there will be some unreacted NCO groups in the polyurethane prepolymer. The prepolymer should have less than 14% unreacted NCO groups. Preferably, the prepolymer has no greater than 8.5% unreacted NCO groups, more preferably from 2.5% to 8%, and most preferably from 5.0% to 8.0% unreacted NCO groups. As the weight percent of unreacted isocyanate groups increases, the hardness of the composition also generally increases.

When the one-shot technique is used to form the polyurethane ionomers, the polytrimethylene ether glycol or blends of polytrimethylene ether glycol with other glycols such as polyester glycol or polycaprolactone glycol is reacted either with a diisocyanate having an acid or ester or ionic moiety such as 5-sulfo-isophthalic acid and 1,3 propane-diol or with a dimethylopropionic acid which is neutralized with a sufficient amount of a suitable cation source and a chain extender based on diols or diamines. When the two-shot (prepolymer) technique is used to form the polyurethane ionomers, the prepolymer having a polytrimethylene ether glycol based diisocyanate is reacted either with a diisocyanate having an acid or ester or ionic moiety such as 5-sulfo-isophthalic acid and 1,3 propane-diol or with a dimethylopropionic acid which is neutralized with a sufficient amount of a suitable cation source and a chain extender based on diols or diamines. The acid moiety is converted into an ionic moiety by selectively neutralizing the acid groups using suitable counter ions or salts. In one embodiment, the neutralization level is from 10 to 80%, more preferably 20 to 70%, and most preferably 30 to 50%. In another embodiment, the neutralization level is from 80 to 100%, more preferably 90 to 100%, and most preferably 95 to 100%. The acid groups may be neutralized with a suitable cation source, such as metal cations and salts thereof, organic amine compounds, ammonium, sodium hydroxide, bases, and combinations thereof. Preferred cation sources are metal cations and salts thereof, wherein the metal is preferably lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc, aluminum, manganese, nickel, chromium, copper, or a combination thereof. In addition, melt flow modifiers such as, for example, fatty acids and salts thereof, particularly stearic, benefic, erucic, oleic, linoelic, and dimerized derivatives thereof may be used. Organic acids and salts of organic acids also may be used.

Either the one-shot or prepolymer method may be employed to produce the functionalized polytrimethylene ether-based polyurethane compositions of the invention; however, the prepolymer technique is preferred because it provides better control of the chemical reaction. The prepolymer method provides a more homogeneous mixture resulting in a more consistent polymer composition. The one-shot method results in a mixture that is inhomogeneous (more random) and affords the manufacturer less control over the molecular structure of the resultant composition.

In the casting process, the functionalized polytrimethylene ether-based polyurethane composition can be formed by chain-extending the polyurethane prepolymer with a single curing agent or blend of curing agents as described further below. The compositions of the present invention may be selected from among both castable thermoplastic and thermoset materials. Thermoplastic polyurethane compositions are typically formed by reacting the isocyanate and polyol compound, each having two (or less) functional groups, at a 1:1 stoichiometric ratio. Thermoset compositions, on the other hand, are cross-linked polymers and are typically produced from the reaction of an isocyanate and hydroxyl-terminated compound, wherein each component has two (or greater) functional groups, at normally a 1.05:1 stoichiometric ratio. In general, thermoset polyurethane compositions are easier to prepare than thermoplastic polyurethanes.

Chain-Extending of Prepolymer

The functionalized polytrimethylene ether-based polyurethane prepolymer can be chain-extended by reacting it with a single curing agent or blend of curing agents. In general, the prepolymer can be reacted with hydroxyl-terminated curing agents, amine-terminated curing agents, or mixtures thereof. The curing agents extend the chain length of the prepolymer and build-up its molecular weight. Normally, the prepolymer and curing agent are mixed so the isocyanate groups and hydroxyl or amine groups are mixed at a 1.05:1.00 stoichiometric ratio.

A catalyst may be employed to promote the reaction between the isocyanate and polyol compounds for producing the prepolymer or between prepolymer and curing agent during the chain-extending step. Preferably, the catalyst is added to the reactants before producing the prepolymer. Suitable catalysts include, but are not limited to, bismuth catalyst; zinc octoate; stannous octoate; tin catalysts such as bis-butyltin dilaurate, bis-butyltin diacetate, stannous octoate; tin (II) chloride, tin (IV) chloride, bis-butyltin dimethoxide, dimethyl-bis[1-oxonedecyl)oxy]stannane, di-n-octyltin bis-isooctyl mercaptoacetate; amine catalysts such as triethylenediamine, triethylamine, and tributylamine; organic acids such as oleic acid and acetic acid; delayed catalysts; and mixtures thereof. The catalyst is preferably added in an amount sufficient to catalyze the reaction of the components in the reactive mixture. In one embodiment, the catalyst is present in an amount from about 0.001 percent to about 1 percent, and preferably 0.1 to 0.5 percent, by weight of the composition.

The hydroxyl chain-extending (curing) agents are preferably selected from the group consisting of ethylene glycol; diethylene glycol; polyethylene glycol; propylene glycol; 2-methyl-1,3 -propanediol; 2-methyl-1,4-butanediol; monoethanolamine; diethanolamine; triethanolamine; monoisopropanolamine; diisopropanolamine; dipropylene glycol; polypropylene glycol; 1,2-butanediol; 1,3-butanediol; 1,4-butanediol; 2,3-butanediol; 2,3-dimethyl-2,3-butanediol; trimethylolpropane; cyclohexyldimethylol; triisopropanolamine; N,N,N′,N′-tetra-(2-hydroxypropyl)-ethylene diamine; diethylene glycol bis-(aminopropyl)ether; 1,5-pentanediol; 1,6-hexanediol; 1,3-bis-(2-hydroxyethoxy) cyclohexane; 1,4-cyclohexyldimethylol; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]cyclohexane; 1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}cyclohexane; trimethylolpropane; polytetramethylene ether glycol, preferably having a molecular weight from about 250 to about 3900; and mixtures thereof. The acid, ester, or ionic derivatives of the hydroxyl curing agents also can be used per this invention.

Suitable amine chain-extending (curing) agents that can be used in chain-extending the polyurethane prepolymer of this invention include, but are not limited to, unsaturated diamines such as 4,4′-diamino-diphenylmethane (i.e., 4,4′-methylene-dianiline or “MDA”), m-phenylenediamine, p-phenylenediamine, 1,2- or 1,4-bis(sec-butylamino)benzene, 3,5-diethyl-(2,4- or 2,6-)toluenediamine or “DETDA”, 3,5-dimethylthio-(2,4- or 2,6-)toluenediamine, 3,5-diethylthio-(2,4- or 2,6-)toluenediamine, 3,3′-dimethyl-4,4′-diamino-diphenylmethane, 3,3′-diethyl-5,5′-dimethyl4,4′-diamino-diphenylmethane (i.e., 4,4′-methylene-bis(2-ethyl-6-methyl-benezeneamine)), 3,3′-dichloro-4,4′-diamino-diphenylmethane (i.e., 4,4′-methylene-bis(2-chloroaniline) or “MOCA”), 3,3′,5,5′-tetraethyl-4,4′-diamino-diphenylmethane (i.e., 4,4′-methylene-bis(2,6-diethylaniline), 2,2′-dichloro-3,3′,5,5′-tetraethyl-4,4′-diamino-diphenylmethane (i.e., 4,4′-methylene-bis(3-chloro-2,6-diethyleneaniline) or “MCDEA”), 3,3′-diethyl-5,5′-dichloro-4,4′-diamino-diphenylmethane, or “MDEA”), 3,3′-dichloro-2,2′,6,6′-tetraethyl-4,4′-diamino-diphenylmethane, 3,3′-dichloro-4,4′-diamino-diphenylmethane, 4,4′-methylene-bis(2,3-dichloroaniline) (i.e., 2,2′,3,3′-tetrachloro-4,4′-diamino-diphenylmethane or “MDCA”), 4,4′-bis(sec-butylamino)-diphenylmethane, N,N′-dialkylamino-diphenylmethane, trimethyleneglycol-di(p-aminobenzoate), polyethyleneglycol-di(p-aminobenzoate), polytetramethyleneglycol-di(p-aminobenzoate); saturated diamines such as ethylene diamine, 1,3-propylene diamine, 2-methyl-pentamethylene diamine, hexamethylene diamine, 2,2,4- and 2,4,4-trimethyl-1,6-hexane diamine, imino-bis(propylamine), imido-bis(propylamine), methylimino-bis(propylamine) (i.e., N-(3-aminopropyl)-N-methyl-1,3-propanediamine), 1,4-bis(3-aminopropoxy)butane (i.e., 3,3′-[1,4-butanediylbis-(oxy)bis]-1-propanamine), diethyleneglycol-bis(propylamine) (i.e., diethyleneglycol-di(aminopropyl)ether), 4,7,10-trioxatridecane-1,13-diamine, 1-methyl-2,6-diamino-cyclohexane, 1,4-diamino-cyclohexane, poly(oxyethylene-oxypropylene) diamines, 1,3- or 1,4-bis(methylamino)-cyclohexane, isophorone diamine, 1,2- or 1,4-bis(sec-butylamino)-cyclohexane, N,N′-diisopropyl-isophorone diamine, 4,4′-diamino-dicyclohexylmethane, 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane, 3,3′-dichloro-4,4′-diamino-dicyclohexylmethane, N,N′-dialkylamino-dicyclohexylmethane, polyoxyethylene diamines, 3,3′-diethyl-5,5′-dimethyl-4,4′-diamino-dicyclohexylmethane, polyoxypropylene diamines, 3,3′-diethyl-5,5′-dichloro-4,4′-diamino-dicyclohexylmethane, polytetramethylene ether diamines, 3,3′,5,5′-tetraethyl-4,4′-diamino-dicyclohexylmethane (i.e., 4,4′-methylene-bis(2,6-diethylaminocyclohexane)), 3,3′-dichloro-4,4′-diamino-dicyclohexylmethane, 2,2′-dichloro-3,3′,5,5′-tetraethyl-4,4′-diamino-dicyclohexylmethane, (ethylene oxide)-capped polyoxypropylene ether diamines, 2,2′,3,3′-tetrachloro-4,4′-diamino-dicyclohexylmethane, 4,4′-bis(sec-butylamino)-dicyclohexylmethane; triamines such as diethylene triamine, dipropylene triamine, (propylene oxide)-based triamines (i.e., polyoxypropylene triamines), N-(2-aminoethyl)-1,3-propylenediamine (i.e., N3 -amine), glycerin-based triamines, (all saturated); tetramines such as N,N′-bis(3-aminopropyl)ethylene diamine (i.e., N4-amine) (both saturated), triethylene tetramine; and other polyamines such as tetraethylene pentamine (also saturated). The amine curing agents used as chain extenders normally have a cyclic structure and a low molecular weight (250 or less). The acid, ester, or ionic derivatives of the amine curing agents also can be used per this invention.

When the polyurethane prepolymer is reacted with hydroxyl-terminated curing agents during the chain-extending step, as described above, the resulting composition is essentially a pure polyurethane composition. On the other hand, when the polyurethane prepolymer is reacted with an amine-terminated curing agent during the chain-extending step, any excess isocyanate groups in the prepolymer will react with the amine groups in the curing agent and create urea linkages.

This chain-extending step, which occurs when the polyurethane prepolymer is reacted with hydroxyl-terminated curing agents, amine-terminated curing agents, or mixtures thereof, builds-up the molecular weight and extends the chain length of the prepolymer. When the polyurethane prepolymer is reacted with hydroxyl-terminated curing agents, a polyurethane composition having urethane linkages is produced. When the polyurethane prepolymer is reacted with amine-terminated curing agents, a polyurethane/urea hybrid composition having urethane and urea linkages is produced. The polyurethane/urea hybrid composition is distinct from the pure polyurethane composition. The concentration of urethane and urea linkages in the hybrid composition may vary. In general, the hybrid composition may contain a mixture of about 10 to 90 wt. % urethane and about 90% to 10 wt. % urea linkages. The resulting polyurethane composition or polyurethane/urea hybrid composition has elastomeric properties based on phase separation of the soft and hard segments. The soft segments, which are formed from the polyol reactants, are generally flexible and mobile, while the hard segments, which are formed from the isocyanate and chain extenders, are generally stiff and immobile.

Golf Ball Construction

Core

The cores in the golf balls of this invention are typically made from rubber compositions containing a base rubber, free-radical initiator agent, cross-linking co-agent, and fillers. The base rubber may be selected, for example, from polybutadiene rubber, polyisoprene rubber, natural rubber, ethylene-propylene rubber, ethylene-propylene diene rubber, styrene-butadiene rubber, and combinations of two or more thereof A preferred base rubber is polybutadiene. Another preferred base rubber is polybutadiene optionally mixed with one or more elastomers such as polyisoprene rubber, natural rubber, ethylene propylene rubber, ethylene propylene diene rubber, styrene-butadiene rubber, polystyrene elastomers, polyethylene elastomers, polyurethane elastomers, polyurea elastomers, acrylate rubbers, polyoctenamers, metallocene-catalyzed elastomers, and plastomers. Highly neutralized olefin-based polymers, as known in the art, also can be used to form the core layer. Such materials are disclosed, for example, in U.S. Pat. No. 6,756,436, the disclosure of which is hereby incorporated by reference. The base rubber typically is mixed with at least one reactive cross-linking co-agent to enhance the hardness of the rubber composition. Suitable co-agents include, but are not limited to, unsaturated carboxylic acids and unsaturated vinyl compounds. A preferred unsaturated vinyl is trimethylolpropane trimethacrylate.

The rubber composition is cured using a conventional curing process. Suitable curing processes include, for example, peroxide curing, sulfur curing, high-energy radiation, and combinations thereof. In one embodiment, the base rubber is peroxide cured. Organic peroxides suitable as free-radical initiators include, for example, dicumyl peroxide; n-butyl-4,4-di(t-butylperoxy)valerate; 1,1-di(t-butylperoxy)3,3,5-trimethylcyclohexane; 2,5-dimethyl-2,5-di(t-butylperoxy)hexane; di-t-butyl peroxide; di-t-amyl peroxide; t-butyl peroxide; t-butyl cumyl peroxide; 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3; di(2-t-butyl-peroxyisopropyl)benzene; dilauroyl peroxide; dibenzoyl peroxide; t-butyl hydroperoxide; and combinations thereof. Cross-linking agents are used to cross-link at least a portion of the polymer chains in the composition. Suitable cross-linking agents include, for example, metal salts of unsaturated carboxylic acids having from 3 to 8 carbon atoms; unsaturated vinyl compounds and polyfunctional monomers (e.g., trimethylolpropane trimethacrylate); phenylene bismaleimide; and combinations thereof In a particular embodiment, the cross-linking agent is selected from zinc salts of acrylates, diacrylates, methacrylates, and dimethacrylates. In another particular embodiment, the cross-linking agent is zinc diacrylate (“ZDA”). Commercially available zinc diacrylates include those selected from Rockland React-Rite and Sartomer.

The rubber compositions also may contain “soft and fast” agents such as a halogenated organosulfur, organic disulfide, or inorganic disulfide compounds. Particularly suitable halogenated organosulfur compounds include, but are not limited to, halogenated thiophenols.

Preferred organic sulfur compounds include, but not limited to, pentachlorothiophenol (“PCTP”) and a salt of PCTP. A preferred salt of PCTP is ZnPCTP. A suitable PCTP is sold by the Struktol Company (Stow, Ohio) under the tradename, A95. ZnPCTP is commercially available from EchinaChem (San Francisco, Calif.). These compounds also may function as cis-to-trans catalysts to convert some cis-1,4 bonds in the polybutadiene to trans-1,4 bonds. Antioxidants also may be added to the rubber compositions to prevent the breakdown of the elastomers. Other ingredients such as accelerators (for example, tetra methylthiuram), processing aids, dyes and pigments, wetting agents, surfactants, plasticizers, as well as other additives known in the art may be added to the rubber composition. The core may be formed by mixing and forming the rubber composition using conventional techniques. These cores can be used to make finished golf balls by surrounding the core with outer core layer(s), intermediate layer(s), and/or cover materials as discussed further below. In another embodiment, the cores can be formed using a highly neutralized polymer compositions as disclosed in U.S. Pat. Nos. 6,756,436, 7,402,629, 7,517,289 and 7,030,192. Furthermore, the cores from the highly neutralized polymer compositions can be further cross-linked using any crosslinkable sources including radiation sources such as gamma or electron beam as well as chemical sources such as peroxides and the like.

Golf balls made in accordance with this invention can be of any size, although the USGA requires that golf balls used in competition have a diameter of at least 1.68 inches and a weight of no greater than 1.62 ounces. For play outside of USGA competition, the golf balls can have smaller diameters and be heavier. For example, the diameter of the golf ball may be in the range of about 1.68 to about 1.80 inches. In one embodiment, as shown in FIG. 2, the core is a single-piece having an outside diameter of about 1.00 to about 1.65 inches. Preferably, the single-piece core has a diameter of about 1.50 to about 1.64 inches. The core generally makes up a substantial portion of the ball, for example, the core may constitute at least about 90% of the ball. The hardness of the core may vary depending upon desired properties of the ball. In general, core hardness is in the range of about 10 to about 75 Shore D and more preferably in the range of about 10 to about 60 Shore D. The compression of the core is generally in the range of about 30 to about 110 and more preferably in the range of about 50 to about 100. In general, when the ball contains a relatively soft core, the resulting a driver spin rate of the ball is relatively low. On the other hand, when the ball contains a relatively hard core, the resulting spin rate of the ball is relatively high. In a second embodiment, as shown in FIG. 3, the core is made up of two pieces. The inner core (22) is made of a rubber composition as described above, while the outer core layer (24) is made of the polyurethane composition of this invention. In a preferred version, the outer core layer has a thickness in the range of about 0.030 to about 0.070 inches and a Shore D surface hardness in the range of about 40 to about 70.

In yet another embodiment, as shown in FIG. 5, the core is made up of three pieces. In the golf ball (35), the multi-layered core (36) includes an inner core layer (36a) preferably formed of polybutadiene or other suitable thermoplastic or thermoset material; an intermediate core layer (36b) formed of the functionalized polyurethane composition of this invention; and an outer core layer (36c) formed of polybutadiene or other suitable thermoplastic or thermoset material. The multi-layered core (36) generally has a total diameter of about 1.00 to about 1.65 inches and preferably a diameter of about 1.45 to about 1.60 inches. The center (36a) generally has a center hardness (Core-H1) in the range of about 10 to about 50 Shore D, preferably 15 to 45 Shore D, and more preferably 20 to 40 Shore D. The intermediate core layer (36b) generally has a hardness (Core-H2) in the range of about 40 to about 75 Shore D, preferably 50 to 70 Shore D, and more preferably 55 to 65 Shore D. The outer core layer (36c) generally has a hardness (Core-H3) in the range of about 20 to 80 Shore D, preferably 40 to 70 Shore D, and more preferably 40 to 60 Shore D. The thickness of the outer core layer (36c) is generally in the range of about 0.030 to about 0.070 inches. In a particular embodiment, Core-H1 is equal to Core-H3. In another particular embodiment, Core-H1 is less than Core-H3, and the difference between Core-H1 and Core-H3 is from 15 to 40, preferably from 15 to 20. In yet another particular embodiment, Core-H1 is greater than Core-H3, and the difference between Core-H1 and Core-H3 is from 15 to 40, preferably from 15 to 20. Preferably, the intermediate layer (36b) has a surface hardness (Core-H2) that is greater than both the center hardness (Core-H1) and surface hardness of the outer core layer (Core-H3). When the functionalized polyurethane composition of this invention is used to form the intermediate layer (36b) and the surface hardness of the core\'s intermediate layer (Core-H1) is greater than Core-H1 and Core-H3, this helps the ball have good resiliency and high initial velocity. As a result, the ball tends to travel longer distances.

Intermediate and Cover Layers

The golf balls of this invention preferably include at least one intermediate layer. As used herein, the term, “intermediate layer” means a layer of the ball disposed between the core and cover. The intermediate layer may be considered an outer core layer or inner cover layer or any other layer disposed between the inner core and outer cover of the ball. The intermediate layer also may be referred to as a casing or mantle layer. The intermediate layer preferably has water vapor barrier properties to prevent moisture from penetrating into the rubber core. The ball may include one or more intermediate layers disposed between the inner core and outer cover.

The functionalized polytrimethylene ether-based polyurethane composition of this invention can be used to make the outer core, intermediate layer, inner cover, and/or outer cover. In some instances, a traditional thermoplastic or thermosetting composition may be used to make one layer and a polytrimethylene ether-based polyurethane composition may be used to make a different layer of the golf ball. If a conventional thermoplastic or thermosetting composition is used in one layer (and the polytrimethylene ether-based polyurethane composition used in a different layer), then a wide variety of thermoplastic or thermosetting materials can be employed. These materials include for example, olefin-based copolymer ionomer resins (for example, Surlyn® ionomer resins and DuPont® HPF 1000 and HPF 2000, commercially available from E. I. du Pont de Nemours and Company; Iotek® ionomers, commercially available from ExxonMobil Chemical Company; Amplify® IO ionomers of ethylene acrylic acid copolymers, commercially available from The Dow Chemical Company; and Clarix® ionomer resins, commercially available from A. Schulman Inc.); polyurethanes; polyureas; copolymers and hybrids of polyurethane and polyurea; polyethylene, including, for example, low density polyethylene, linear low density polyethylene, and high density polyethylene; polypropylene; rubber-toughened olefin polymers; acid copolymers, for example, poly(meth)acrylic acid, which do not become part of an ionomeric copolymer; plastomers; flexomers; styrene/butadiene/styrene block copolymers; styrene/ethylene-butylene/styrene block copolymers; dynamically vulcanized elastomers; copolymers of ethylene and vinyl acetates; copolymers of ethylene and methyl acrylates; polyvinyl chloride resins; polyamides, poly(amide-ester) elastomers, and graft copolymers of ionomer and polyamide including, for example, Pebax® thermoplastic polyether block amides, commercially available from Arkema Inc; cross-linked trans-polyisoprene and blends thereof; polyester-based thermoplastic elastomers, such as Hytrel®, commercially available from E. I. du Pont de Nemours and Company; polyurethane-based thermoplastic elastomers, such as Elastollan®, commercially available from BASF; synthetic or natural vulcanized rubber; and combinations thereof.

The functionalized polytrimethylene ether-based polyurethane composition constituting the layer(s) of the golf ball may contain additives, ingredients, and other materials in amounts that do not detract from the properties of the final composition. These additive materials include, but are not limited to, activators such as calcium or magnesium oxide; fatty acids such as stearic acid and salts thereof; fillers and reinforcing agents such as organic or inorganic particles, for example, clays, talc, calcium, magnesium carbonate, silica, aluminum silicates zeolites, powdered metals, and organic or inorganic fibers, plasticizers such as dialkyl esters of dicarboxylic acids; surfactants; softeners; tackifiers; waxes; ultraviolet (UV) light absorbers and stabilizers; antioxidants; optical brighteners; whitening agents such as titanium dioxide and zinc oxide; dyes and pigments; processing aids; release agents; and wetting agents.

The functionalized polytrimethylene ether-based polyurethanes of this invention may be blended with non-ionomeric and olefin-based ionomeric polymers to form the composition that will be used to make the golf ball layer. Examples of non-ionomeric polymers include vinyl resins, polyolefins including those produced using a single-site catalyst or a metallocene catalyst, polyurethanes, polyureas, polyamides, polyphenylenes, polycarbonates, polyesters, polyacrylates, engineering thermoplastics, and the like. The blend may contain about 10 to about 90% by weight of the polyurethane and about 90 to about 10% by weight of a non-ionomeric polymer. Olefin-based ionomers, such as ethylene-based copolymers, normally include an unsaturated carboxylic acid, such as methacrylic acid, acrylic acid, or maleic acid. Other possible carboxylic acid groups include, for example, crotonic, maleic, fumaric, and itaconic acid. Low acid and high acid olefin-based ionomers, as well as blends of such ionomers, may be used. The acidic group in the olefin-based ionic copolymer is partially or totally neutralized with metal ions such as zinc, sodium, lithium, magnesium, potassium, calcium, manganese, nickel, chromium, copper, or a combination thereof. For example, ionomeric resins having carboxylic acid groups that are neutralized from about 10 percent to about 100 percent may be used. In one embodiment, the neutralization level is from 10 to 80%, more preferably 20 to 70%, and most preferably 30 to 50%. In another embodiment, the neutralization level is from 80 to 100%, more preferably 90 to 100%, and most preferably 95 to 100%. The cation source used to neutralize the acid groups of the olefin-based copolymer ionomer may be the same or different cation source used to neutralize the acid groups in the polytrimethylenee ether-based polyurethane compound as discussed above. The blend may contain about 10 to about 90% by weight of the polytrimethylene ether-based polyurethane and about 90 to about 10% by weight of a partially, highly, or fully-neutralized olefin-based ionomeric copolymer.

The golf balls of the present invention preferably have a “coefficient of restitution” (“COR”) of at least 0.750 and more preferably at least 0.800 (as measured per the test methods below) and a compression of from about 70 to about 110, preferably from 90 to 100 (as measured per the test methods below).

Golf Ball Construction

The polyurethane compositions of this invention may be used with any type of ball construction known in the art. Such golf ball designs include, for example, three-piece and four-piece designs. The core, intermediate casing, and cover portions making up the golf ball each can be single or multi-layered. In FIG. 1, one version of a golf ball that can be made in accordance with this invention is generally indicated at (10). Various patterns and geometric shapes of dimples (11) can be used to modify the aerodynamic properties of the golf ball (10). The dimples (11) can be arranged on the surface of the ball (10) using any suitable method known in the art.

Referring to FIG. 2, a three-piece golf ball (12) that can be made in accordance with this invention is illustrated. In this version, the ball (12) includes a solid core (14), an intermediate casing layer (16) made of the polyurethane composition, and cover layer (18). The core (14) is made of polybutadiene rubber or other suitable material as described above and has a diameter in the range of about 1.30 to about 1.60 inches. The cover layer (18) is made of a thermoplastic composition or thermoset composition as described above. For example, the cover layer (18) may be formed from a compound selected from the group consisting of olefin-based ionomers; polyesters; polyester-ether elastomers; polyester-ester elastomers; polyamides; polyamide-ether elastomers, and polyamide-ester elastomers; polyurethanes, polyureas, and polyurethane-polyurea hybrids; and mixtures thereof The range of thickness for the polyurethane intermediate layer (16) may vary, but it generally has a thickness of 0.010 to 0.030 inches, preferably 0.015 to 0.025 inches, and more preferably about 0.1015 to 0.020 inches. The intermediate layer (16) preferably has a Shore D surface hardness of 50 to 75, preferably 55 to 70, and most preferably 60 to 65. The thickness of the intermediate layer is preferably in the range of about 0.010 to 0.040 inches.

In one preferred version of a three-piece golf ball, the core has a first Shore D surface hardness of H1 in the range of about 10 to 60; the intermediate layer surrounding the core has a second Shore D surface hardness of H2 in the range of about 50 to 75 and a thickness in the range of about 0.010 to about 0.040 inches; and the cover layer surrounding the intermediate layer has a third Shore D surface hardness of H3 in the range of about 30 to 60. The ratio of H3 to H1 is in the range of about 0.6 to 6.0 In one version, H2 is greater than H3; while, in a second version, H3 is greater than H2.

In another embodiment of a three-piece golf ball, the core surface hardness is at least 83 JIS C or 52 Shore D, the casing surface hardness measured on the ball is at least 90 JIS C or 91 Shore C or 62 Shore D, the ten (10) days aged button hardness for the casing layer is at least 90 JIS C or 60 Shore D, the ball cover hardness is at least 81 JIS C or 82 Shore C or 59 Shore D and the ten (10) days aged button hardness for the cover layer is at least 72 JIS C or 72 Shore C or 47 Shore D.

In a further embodiment for a three-piece golf ball, the hardness gradient from the center to the outer core surface hardness is 5 JIS C or below, the outer core surface hardness is at least 83 JIS C or 52 Shore D, the casing surface hardness measured on the ball is at least 90 JIS C or 91 Shore C or 62 Shore D, the ten (10) days aged button hardness for the casing layer is at least 90 JIS C or 60 Shore D, the ball cover hardness is at least 81 JIS C or 82 Shore C or 59 Shore D and the ten (10) days aged button hardness for the cover layer of at least 72 JIS C or 72 Shore C or 47 Shore D.

In yet another three-piece golf ball, the core surface hardness is at least 88 JIS C or higher, the casing surface hardness measured on the ball is at least 85 JIS C or less, the ten (10) days aged button hardness for the casing layer is at least 85 JIS C or less, the ball cover hardness is at least 81 JIS C or 82 Shore C or 59 Shore D, and the ten (10) days aged button hardness for the cover layer is at least 72 JIS C or 72 Shore C or 47 Shore D.

It should be understood the three-piece golf ball construction shown in FIG. 2 is for illustrative purposes only and not meant to be restrictive. Other three-piece constructions can be made per this invention. For example, the cover layer (18) may be made of the polyurethane composition of this invention. In such an example, the cover layer (18) may have a thickness in the range of about 0.010 to about 0.030 inches and a Shore D surface hardness (H3) in the range of about 45 to about 65. In this version, the intermediate layer has a Shore D surface hardness (H2) in the range of about 50 to 75. In one version, H2 is greater than H3; while in second version, H3 is greater than H2.

In FIG. 3, a four-piece golf ball (20) having a multi-layered core is illustrated. The multi-layered core includes an inner core (22) and outer core layer (24). The inner core (22) may be made of a first rubber material, for example, polybutadiene, or highly neutralized polymer (HNP) and the outer core layer (24) may be made of the functionalized polytrimethylene ether-based polyurethane composition of this invention. The golf ball further includes an intermediate casing layer (26) and cover layer (28). Conventional thermoplastic or thermoset resins such as olefin-based ionomeric copolymers, polyamides, polyesters, polycarbonates, polyolefins, polyurethanes, and polyureas as described above can be used to make the casing layer (26) and/or cover layer (28). In such multi-layered cores, the inner core (22) preferably has a diameter of about 0.50 to about 1.30 inches, more preferably 1.00 to 1.15 inches, and is relatively soft (that is, it may have a compression of less than about 30.) Meanwhile, the encapsulating outer core layer (24) generally has a thickness of about 0.030 to about 0.070 inches, preferably 0.035 to 0.065 inches and is relatively hard (compression of about 70 or greater.) The outer core layer (24) preferably has a Shore D surface hardness in the range of about 40 to about 70. That is, the two-piece core, which is made up of the inner core (22) and outer core layer (24), preferably has a total diameter of about 1.50 to about 1.64 inches, more preferably 1.510 to 1.620 inches, and a compression of about 80 to about 115, more preferably 85 to 110.

In another version, the four-piece golf ball includes an inner core surface hardness of at least 76 JIS C or 43 Shore D, an outer core surface hardness measured on the ball at least 89 JIS C or 60 Shore D, a casing surface hardness measured on the ball at least 93 JIS C or 92 Shore C or 61 Shore D, a ten (10) days aged button hardness for the casing layer of at least 90 JIS C or 60 Shore D, a ball cover hardness of at least 81 JIS C or 82 Shore C or 59 Shore D and a ten (10) days aged button hardness for the cover layer of at least 72 JIS C or 72 Shore C or 47 Shore D.

In still another version, the four-piece golf ball includes an inner core surface hardness of at least 76 JIS C or 43 Shore D, an outer core surface hardness measured on the ball of at least 88 JIS C or greater, a casing surface hardness measured on the ball of at least 85 JIS C or less, a ball cover hardness of at least 81 JIS C or 82 Shore C or 59 Shore D and a ten (10) days aged button hardness for the cover layer of at least 72 JIS C or 72 Shore C or 47 Shore D.

In FIG. 3, the illustrated four-piece golf ball is not meant to be limiting. Other four-piece constructions can be made per this invention. For example, the intermediate casing layer (26) and/or cover layer (28) may be made of the polyurethane composition of this invention.

Turning to FIG. 4, a four-piece golf ball (30) having a multi-layered cover is shown. The ball (30) includes a solid, one-piece rubber core (33), an intermediate layer (34), and multi-layered cover constituting an inner cover layer (31) and outer cover layer (32). In this version, the inner cover layer (31) is made of the polyurethane composition of this invention and the outer cover layer (32) is made of a conventional thermoplastic or thermosetting resin. The inner cover layer (31) preferably has a thickness of about 0.020 to about 0.050 inches and Shore D material hardness of about 50 to about 70. The outer cover layer (32), which surrounds the inner cover layer (31), may be made of a thermoplastic or thermoset composition. For example, the outer cover (32) may be made of polyurethane, polyurea, ionomer resin or any of the other cover materials described above. The outer cover layer (32) preferably has a thickness in the range of about 0.020 to about 0.035 inches and a Shore D material hardness in the range of about 45 to about 65. The four-piece golf ball construction shown in FIG. 4 is one example and other four-piece constructions can be made in accordance with this invention. For example, in another version, the outer cover layer (32) may be made of the polyurethane composition of this invention.

Lastly, in FIG. 5, the golf ball (35) includes a multi-layered core (36) having layers of different hardness as described above. Particularly, the core includes an inner core layer (36a) preferably formed of polybutadiene or other suitable thermoplastic or thermoset material; an intermediate core layer (36b) formed of the polyurethane composition of this invention; and an outer core layer (36c) formed of polybutadiene or other suitable thermoplastic or thermoset material. The outer cover (40) may be made of the polyurethane composition of this invention. Other versions of a golf ball having a multi-layered core (36) may be made in accordance with this invention. For example, a golf ball having a multi-layered core; an inner cover layer made of an ionomer resin or other traditional thermoplastic or thermoset material; and a polyurethane outer cover can be constructed.

As noted above, the golf ball constructions shown in FIGS. 1-5 are for illustrative purposes only and are not meant to be restrictive. A wide variety of golf ball constructions may be made in accordance with the present invention depending upon the desired properties of the ball so long as at least one layer contains the polyurethane composition of this invention. As discussed above, such constructions include, but are not limited to, three-piece, and four-piece designs and the cores, intermediate layers, and/or covers may be single or multi-layered. Numerous other golf ball constructions having layers made of the polyurethane composition of this invention are contemplated. For example, in another embodiment, a three-piece cover golf ball can be made. The inner core has a surface hardness of at least 83 Shore C or 45 Shore D, the innermost cover layer has a surface hardness measured on the ball of at least 90 Shore C or 60 Shore D, the intermediate layer has a surface hardness measured on the ball of at least 93 Shore C or 62 Shore D. The ten (10) day aged button hardness for the casing layer is at least 65 Shore D, the ball cover hardness is at least 80 Shore C or 59 Shore D, and the ten (10) day aged button hardness for the cover layer is at least 72 JIS C or 72 Shore C or 47 Shore D.

In another example, a golf ball having a dual core and single cover layer can be made. The core has a surface hardness of at least 74 JIS C or 40 Shore D, an outer core surface surface hardness measured on the ball of at least 85 JIS C or 55 Shore D, a ball cover hardness of at least 55 Shore D and a ten (10) day aged button hardness for the cover layer of at least 56 Shore D.

In yet another example, a two-piece golf ball having a single core and a single cover can be made. The core has a surface hardness of at least 78 JIS C or 44 Shore D, a ball cover hardness of at least 63 Shore D, and a ten (10) day aged button hardness for the cover layer of at least 64 Shore D. The present invention also includes a two-piece golf ball having a core and a cover wherein the cover is formed using a functionalized polytrimethylene ether based polyurethanes with acid, ester, or ionic moieties and the core is coated with a moisture barrier composition to prevent moisture from penetrating into the core. Preferably, the moisture barrier composition has a moisture vapor transmission rate (MVTR) of 12.5 g-mil/100 in2/day or less as disclosed in the U.S. Pat. Nos. 7,357,733, 6,932,720, and 6,632,147, the disclosures of which are hereby incorporated by reference.

The golf balls of this invention may be constructed using any suitable technique known in the art. These methods generally include compression molding, flip molding, injection molding, retractable pin injection molding, reaction injection molding (RIM), liquid injection molding (LIM), casting, vacuum forming, powder coating, flow coating, spin coating, dipping, spraying, and the like.

The polyurethane compositions of this invention should provide the golf ball with advantageous properties and features. Compositions containing the polyurethane compositions, which have been developed in accordance with this invention, can be used in various ball constructions to provide desirable playing performance properties. For example, the compositions may be used to make the outer core, intermediate layer, and/or inner cover. The resulting golf ball has sufficient hardness and good impact durability. The ball has improved resiliency so that it shows good flight distance when hit off a tee. At the same time, the ball has a soft “feel” so that its flight path can be controlled on approach shots near the green.

It should be understood that concentrations, amounts, and other numerical data presented herein in a range format are used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted to include not only the explicitly recited limits of 1 to about 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, and the like. The same principle applies to ranges reciting only one numerical value, such as “less than about 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

The invention is further illustrated by the following examples and test methods, although these examples and test methods should not be construed as limiting the scope of the invention.

Test Methods

Compression The compression value of a golf ball or a golf ball subassembly (for example, golf ball core) is an important property affecting the ball\'s playing performance. For example, the compression of the core can affect the ball\'s spin rate off the driver as well as the “feel” of the ball as the club face makes impact with the ball. In general, balls with relatively low compression values have a softer feel. As disclosed in Jeff Dalton\'s Compression by Any Other Name, Science and Golf IV, Proceedings of the World Scientific Congress of Golf (Eric Thain ed., Routledge, 2002) (“J. Dalton”) several different methods can be used to measure compression including Atti compression, Riehle compression, load/deflection measurements at a variety of fixed loads and offsets, and effective modulus. For purposes of the present invention, “compression” refers to Atti compression and is measured according to a known procedure, using an Atti compression device, wherein a piston is used to compress a ball against a spring.

The travel of the piston is fixed and the deflection of the spring is measured. The measurement of the deflection of the spring does not begin with its contact with the ball; rather, there is an offset of approximately the first 1.25 mm (0.05 inches) of the spring\'s deflection. Cores having a very low stiffness will not cause the spring to deflect by more than 1.25 mm and therefore have a zero compression measurement. The Atti compression tester is designed to measure objects having a diameter of 1.680 inches; thus, smaller objects, such as golf ball cores, must be shimmed to a total height of 1.680 inches to obtain an accurate reading. Conversion from Atti compression to Riehle (cores), Riehle (balls), 100 kg deflection, 130-10 kg deflection or effective modulus can be carried out according to the formulas given in J. Dalton.

Coefficient of Restitution (COR) The “coefficient of restitution” or “COR” of a golf ball means the ratio of a ball\'s rebound velocity to its initial incoming velocity when the ball is fired out of an air cannon into a rigid vertical plate. The COR for a golf ball is written as a decimal value between zero and one. A golf ball may have different COR values at different initial velocities. The United States Golf Association (USGA) sets limits on the initial velocity of the ball so one objective of golf ball manufacturers is to maximize the COR under these conditions. Balls with a higher rebound velocity have a higher COR value. Such golf balls rebound faster, retain more total energy when struck with a club, and have longer flight distance. In general, the COR of the ball will increase as the hardness of the ball is increased.

In the present invention, COR is determined according to a known procedure, wherein a golf ball or golf ball subassembly (for example, a golf ball core) is fired from an air cannon at two given velocities and a velocity of 125 ft/s is used for the calculations. Ballistic light screens are located between the air cannon and steel plate at a fixed distance to measure ball velocity. As the ball travels toward the steel plate, it activates each light screen and the ball\'s time period at each light screen is measured. This provides an incoming transit time period which is inversely proportional to the ball\'s incoming velocity. The ball makes impact with the steel plate and rebounds so it passes again through the light screens. As the rebounding ball activates each light screen, the ball\'s time period at each screen is measured. This provides an outgoing transit time period which is inversely proportional to the ball\'s outgoing velocity. The COR is then calculates as the ratio of the ball\'s outgoing transit time period to the ball\'s incoming transit time period (COR=Vout/Vin=Tin/Tout).

Hardness The surface hardness of a golf ball layer (or other spherical surface) is obtained from the average of a number of measurements taken from opposing hemispheres, taking care to avoid making measurements on the parting line of the core or on surface defects such as holes or protrusions. Shore D Hardness measurements are made pursuant to ASTM D-2240 “Indentation Hardness of Rubber and Plastic by Means of a Durometer.” Because of the curved surface of the golf ball layer, care must be taken to ensure that the golf ball or golf ball subassembly is centered under the durometer indentor before a surface hardness reading is obtained. A calibrated digital durometer, capable of reading to 0.1 hardness units, is used for all hardness measurements and is set to take hardness readings at 1 second after the maximum reading is obtained. The digital durometer must be attached to and its foot made parallel to the base of an automatic stand. The weight on the durometer and attack rate conforms to ASTM D-2240. It should be understood that there is a fundamental difference between “material hardness” and “hardness as measured directly on a golf ball.” For purposes of the present invention, material hardness is measured according to ASTM D2240 and generally involves measuring the hardness of a flat “slab” or “button” formed of the material. Surface hardness as measured directly on a golf ball (or other spherical surface) typically results in a different hardness value. The difference in “surface hardness” and “material hardness” values is due to several factors including, but not limited to, ball construction (that is, core type, number of cores and/or cover layers, and the like); ball (or sphere) diameter; and the material composition of adjacent layers. It also should be understood that the two measurement techniques are not linearly related and, therefore, one hardness value cannot easily be correlated to the other. JIS-C hardness was measured according to the test methods JIS K 6301-1975. Shore C hardness was measured according to the test methods D2240-05.

The following prophetic examples describe functionalized polytrimethylene ether-based polyurethane ionomer compositions that can be prepared and used to make golf balls of this invention. As discussed above, the compositions can be used to make any layer of the golf ball layer (for example, outer cover, intermediate, inner cover, or outer core layer) The compositions provide the golf ball with high impact durability and scuff-resistance as well as high resiliency and other desirable properties.

This example illustrates preparation of a functionalized polytrimethylene ether-based polyurethane or polyurethane/polyurea hybrid ionomer from a polytrimethylene ether glycol, m-phenylene diisocyanate, and ether-ester diol based on 5-sulfo-isophthalic acid with 1,3-propane diol, which is chain-extended with a diamine such as 1,6-hexadiamine and further neutralized in the presence of a sufficient amount of suitable cation source such as sodium hydroxide to achieve a desired neutralization of about 50 to 90%. In this example, a one-shot manufacturing technique was used to combine the ingredients. However, it also is recognized that the above functionalized polymer can be prepared by a pre-polymer method by reacting a pre-polymer based on an isocyanate, a polytrimethylene ether glycol and an ether-ester diol based on 5-sulfo-isophthalic acid with 1,3-propane diol in the presence of a suitable chain extending agent and a cation source.

In this example, the one-shot method is used to prepare a functionalized polytrimethylene ether-based polyurethane ionomer from a polytrimethylene ether glycol, m-phenylene diisocyanate, ether-ester diol based on 5-sulfo-isophthalic acid and 1,3-propane diol, and N,N′-diethyl amino-diphenylmethane chain terminator and a sufficient amount of sodium hydroxide to achieve a neutralization of the acid content to about 60%.

In this example, the one-shot method is used to prepare a functionalized polytrimethylene ether-based polyurethane ionomer from polytrimethylene ether glycol, m-phenylene diisocyanate, ether-ester diol based on 5-sulfo-isophthalic acid and 1,3-propane diol and N,N′-diethyl amino-diphenylmethane chain terminator and a sufficient amount of sodium hydroxide to achieve a neutralization of the acid content to about 100%.

The above-described compositions also can be prepared by a two-shot method, that is, by reacting previously made prepolymers with polyols and chain extenders.

It is understood that the golf balls described and illustrated herein represent only presently preferred embodiments of the invention. It is appreciated by those skilled in the art that various changes and additions can be made to such golf balls without departing from the spirit and scope of this invention. It is intended that all such embodiments be covered by the appended claims.