JP2008055174A - Multilayer golf ball having thick inner cover - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf ball having a high restitution coefficient even if an impact speed is slow or fast. <P>SOLUTION: The golf ball comprises a core having a diameter of 0.5-1.4 inches, a compression of approximately 45 or lower and the restitution coefficient of 0.730-0.810, a cast polyurea cover, and an interlayer arranged between the core and the cover and having the thickness of 0.11 inches or greater and composed of highly neutralized composition having a water vapor transmission rate of 8 g-mil/100 in<SP>2</SP>/day or lower. Compression of approximately 70-100 is achieved by a combination of the core and the interlayer. The restitution coefficient of the golf ball is 0.805-0.820 when it is measured at an input speed of 125 ft/s. The restitution coefficient is 0.75 or greater when it is measured at an input speed of 160 ft/s, and the compression of the golf ball is 75-105. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a golf ball having a large coefficient of restitution and small deformation, and more specifically to a golf ball having a large coefficient of restitution even if the club speed is large.

  This application is a continuation-in-part of US patent application 11 / 267,487, which is a continuation-in-part of US patent application 10 / 267,487, filed May 7, 2004.

  Golf balls have been designed to achieve specific play characteristics. These characteristics are generally the initial ball speed, coefficient of restitution (COR), compression, weight distribution and spin speed of the ball and can be optimized for various types of players.

  Conventional golf balls can be divided into two general classes: solids and spools. Solid golf balls are available in single-layer, double-layer (ie, solid core and cover), and multi-layer (ie, solid-core two-piece (ie, one or more solid core and / or one or more cover) golf balls. A wound ball typically includes a solid, hollow, or liquid-filled center that is typically surrounded by a stretched elastic material and a cover.

  In general, the hardness of a golf ball or golf ball core is one of many factors employed in the heel of designing a golf ball. Typically, if the ball is hard, for example, it has high compression and the deformation when hit with a club is small, the ball has a large COR and the initial velocity after hitting with a golf club is high. When the ball becomes softer, for example, when the compression is smaller and the deformation is larger, a “soft” feeling is realized and the control is more prepared with a short iron in green side play. Recently developed solid balls have a core, at least one intermediate layer, and a cover. The intermediate layer improves other play characteristics of the solid ball and may be manufactured from a thermoset or thermoplastic material.

  Recent developments in golf ball design make it possible to achieve golf balls with low compression for soft “feel” and high COR for long flight distances. However, the COR of a low compression ball decreases as the impact speed of the golf club increases.

  There remains a need in the industry for low compression golf balls that have a high coefficient of restitution, whether impact speed is small or large.

[Definition]
The following terms employed in this application are defined in terms of the following numbered ASTM tests: That is, specific gravity ASTM D-792, flexural modulus ASTM D-790, Shore D hardness ASTM D-2240, and Shore C hardness ASTM D-2240. The ASTM D-792 test was performed at laboratory conditions with a temperature of 20-23 ° C.

  As used herein, the terms “point” and “compression point” refer to a compression scale, or compression scale based on the ATTI Engineering Tester. This scale is well known to those skilled in the art and is employed to determine the relative compression of the core or ball. Compression is measured using a manual instrument ("Atti Gauge") from Atti Engineering Company of Union City, New Jersey, applying a spring load force to the golf ball center, golf ball core, or golf ball to be measured. The The instrument is equipped with a Federal Dial Gauge Model D81-C and uses a calibration spring under a known load. The sphere to be inspected receives a force of 0.2 inches (5 mm) against this spring. If the spring is compressed by 0.2 inches, the compression is evaluated as 100, and if the spring is compressed by 0.1 inches, the compression value is evaluated as zero. To explain more clearly, a soft material has a smaller Atti compression value than a material that is hard and hard to shrink. The compression measured with this device is also called PGA compression.

  As used herein, “COR” refers to the coefficient of restitution, which is obtained by dividing the ball rebound speed by its initial speed (ie, input speed). This test is performed by firing a sample from an air cannon to a vertical steel plate at a test speed (75 to 150 ft / s). A golf ball with a large COR consumes a smaller fraction of the total energy when it hits and bounces off a plate, compared to a ball with a small COR. Unless otherwise stated, the reported COR values are those determined at an input speed of 125 ft / s.

  As used herein, the term “copolymer” refers to a polymer made from two or more monomers. However, the monomers are not identical.

  As used herein, the term “terpolymer” refers to a polymer made from three monomers. However, the monomers are not identical.

  As used herein, the term “filler” includes any compound or composition that can be employed to modify the density and other properties of the subject gait ball core.

  As used herein, the term “phr”, in the context of batch formulation, refers to parts by weight of a component relative to 100 parts of a base composition (eg, elastomer).

  As used herein, the term “Mooney viscosity” refers to a unit employed to measure the plasticity of raw or unvulcanized rubber. The Mooney unit plasticity is equal to the torque applied to the disk in a container that rotates at 2 revolutions per minute, including rubber at a temperature of 100 ° C., measured at any scale. The measurement of Mooney viscosity is specified in ASTM D-1646.

  As used herein, the term “about” is understood to refer to all such numbers, all such numbers within a range, in relation to one or more numbers and ranges of numbers. I want to be.

Detailed Description of the Invention

  The golf balls of the present invention may have any one of a variety of structures such as two-piece, multilayer and wound balls, which have various cores, interlayers, covers and coatings. The cover and core of the present invention include a structure having one or more layers. The core may be the only single layer having the entire core from the center to the outer perimeter, and may have the center and at least one outer cover layer surrounding it. The innermost part of the center and core is preferably solid, but may be hollow, liquid filled, gel filled or gas filled. The outer core layer may be a wound layer made from a pulled elastic material. The golf ball cover of the present invention may include a double cover with one or more layers, for example, an inner and outer cover layer. Optionally, an intermediate layer disposed between the core and the cover may be incorporated. The intermediate layer, when present, may have one or more layers and is again referred to as the inner cover layer, outer core layer, or mantle layer, as so called in the art.

  According to the present invention, a low compression, high COR layer is provided on the golf ball, which is supported by the low strain layer or reinforced by other techniques. Preferably, the low compression, high COR layer is made from a polymer composition comprising a halogenated thiophenol compound. Such rubber and halogenated thiophenol compositions are fully disclosed in US Pat. No. 6,635,716, the disclosure of which is hereby incorporated by reference.

  Preferred core compositions have a base rubber compound, a co-reactant, a filler, an optional halogenated thiophenol compound, and a co-crosslinking or initiator.

The base rubber compound typically includes natural or synthetic rubber. A preferred base rubber is 1,4-polybutadiene having a cis-structure of at least 40%, preferably at least 90%, and most preferably at least about 95%. Most preferably, the base rubber is a high Mooney viscosity rubber. Preferably, the Mooney viscosity of the base rubber is greater than about 35, more preferably greater than about 50. Preferably, the polybutadiene rubber has a molecular weight of greater than about 400,000 and its polydispersity is no greater than 2. A general indicator of the degree of dispersion of the molecular weight of a polymer is polydispersity, which is defined as the non-weight of the weight average molecular weight _{Nw to} the number average molecular weight _Mn . Polydispersity (“dispersibility”) is also an indicator of the degree to which polymer chains share the same degree of polymerization. Since _Nw is always greater than or _{equal to Mn} , by definition, polydispersity is greater than or _equal to 1.0. Such rubber compounds are commercially available from Bayer of Akron, OH, Ube Industries of Tokyo (UBE Industries of Tokyo, Japan), and Shell of Houston, TX. . To modify the core properties, the polybutadiene may be mixed with other elastomers known in the art, such as natural rubber, polyisoprene rubber and / or styrene-butadiene rubber.

  Suitable co-reactants include diacrylate, dimethacrylate, or metal salts of monomethacrylate. Preferably, the co-reactant is zinc diacrylate (ZDA) and is in an amount of about 5 to about 40, more preferably in an amount of about 5 to about 30, most preferably 100 parts of rubber compound (phr). , From about 10 to about 20. Suitable crosslinkers may be any of the known polymerization initiators that decompose during the cure cycle. Suitable initiators are organic peroxide compounds such as dicumyl peroxide. In pure form, the preferred amount of oxyperoxide is from about 0.25 phr to about 2.5 phr. Any desired amount of any filler can be used to modify the specific gravity, flexural modulus, moment of inertia, flow properties, and other core properties. Suitable fillers include, but are not limited to, tungsten, zinc oxide, zinc sulfate, silica, metal oxide, ceramic and fiber.

  The polybutadiene rubber composition of the present invention may optionally contain a halogenated thiophenol compound. The halogenated thiophenol is preferably present from 0.01 pph to about 5 pph, more preferably from about 2.2 pph to about 5 pph, and most preferably from about 2.3 pph to 4 pph. The halogenated thiophenol compound is pentafluorothiophenol; 2-fluorothiophenol; 3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol; 2,4-fluorothiophenol; 3,5-fluorothiophenol; 2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol; 2,3,4,5-tetrafluorothiophenol; 2,3,5 4-chlorotetrafluorothiophenol; pentachlorothiophenol; 2-chlorothiophenol; 3-chlorothiophenol; 4-chlorothiophenol; 2,3-chlorothiophenol; -Chlorothiophenol; 3,4-Chlorothiop 3,5-chlorothiophenol; 2,3,4-chlorothiophenol; 3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol; 2,3,5,6 Pentachlorothiophenol; 2-bromothiophenol; 3-bromothiophenol; 4-bromothiophenol; 2,3-bromothiophenol; 2,4-bromothiophenol; 3,4-bromo 3,5-bromothiophenol; 2,3,4-bromothiophenol; 3,4,5-bromothiophenol; 2,3,4,5-tetrabromothiophenol; 6-tetrabromothiophenol; pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol; 4-iodo 2,3-iodothiophenol; 3,4-iodothiophenol; 3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol; -Iodothiophenol; 2,3,4,5-tetraiodothiophenol; 2,3,5,6-tetraiodothiophenol; and zinc salts thereof, metal salts thereof and mixtures thereof. The metal salts are zinc, calcium, potassium, magnesium, sodium, and lithium, with zinc being preferred. Pentachlorothiophenol is commercially available from Struktol Company, Stow, OH. Pentachlorothiophenol is available through the market in pure form or in salt form from Echinachem of San Francisco, Calif. Zinc pentachlorothiophenol is available from Echinachem (San Francisco, Calif.).

  A preferred polybutadiene rubber composition may further comprise an α, β-unsaturated carboxylic acid or metal salt thereof, an organic peroxide, and a filler. Also as discussed in the '448 patent application, another preferred polybutadiene rubber compound having a halogenated thiophenol is a medium Mooney viscosity polybutadiene having a viscosity in the range of about 40 to about 60 Mooney.

  The present invention also relates to “modified” soft, resilient thermoplastic ionomers for golf ball intermediate layers, preferably thick intermediate layers, disposed between a core and a cover. These “soft” ionomers typically comprise a melt blend of (a) an acid copolymer or a melt processable ionomer prepared as described above and (b) one or more organic acids or salts thereof. More than 80%, preferably more than 90% of all acids (a) and (b) are neutralized by the cation source. Preferably, 100% of all acids (a) and (b) are neutralized with a cation source. Preferably, more cation source is used to neutralize acids (a) and (b) than is required for neutralization of acids (a) and (b). It is preferably blended with a fatty acid or a fatty acid salt.

  An organic acid or salt thereof is added sufficient to increase the flexibility of the copolymer. Preferably, an organic acid or salt thereof is added in an amount sufficient to substantially remove residual ethylene crystallinity of the copolymer.

  Preferably, the organic acid or salt thereof is added by at least about 5% (by weight) based on the total amount of copolymer and organic acid. More preferably, the organic acid or salt thereof is added at least about 15%, even more preferably at least about 20%. Preferably, the organic acid is added up to about 50% (weight basis) based on the total amount of copolymer and organic acid. More preferably, the organic acid or salt thereof is added up to about 40%, even more preferably up to about 35%. The non-volatile, non-imigrate organic acid is preferably one or more aliphatic, monofunctional organic acids or salts thereof, as described below. Yes, specifically one or more aliphatic, monofunctional saturated or unsaturated organic acids having less than 36 carbon atoms, preferably stearic acid or oleic acid. Most preferred are fatty acids or fatty acid salts.

Fatty acid (salt) modification processes are known in the art. Specifically, the modified highly neutralized soft elastic acid copolymer ionomer of the present invention can be produced by the following (a) and (b).
(A) (1) an ethylene, α, β-ethylenically unsaturated C _3-8 carboxylic acid copolymer or melt processable ionomer thereof, which has been crystallized by adding a softening monomer or other means, (2) A non-volatile, non-migrating organic acid that substantially enhances elasticity and destroys (preferably removes) the remaining ethylene crystallinity is melt blended simultaneously or sequentially, and simultaneously and sequentially In addition,
(B) the neutralization level of all acid moieties (including the acid moiety in the acid copolymer and, if the non-volatile, non-migratory organic acid is an organic acid) to the desired level A sufficient amount of cation source is added.

  The weight ratio of X to Y in the composition is at least about 1:20. Preferably, the weight ratio of X to Y is at least about 1:15, more preferably about 1:10. Further, the weight ratio of X to Y in the composition is up to about 1: 1.67, more preferably up to about 1: 2. Most preferably, the weight ratio of X to Y in the composition is up to about 1: 2.2.

  The acid copolymer used to produce the ionomer in this invention is preferably a "direct" acid copolymer (including high levels of softening monomer). As noted above, the acid copolymer is at least partially neutralized, preferably at least about 40% of X in the composition is neutralized. More preferably, at least about 55% of X is neutralized. More preferably at least about 70%, and most preferably at least about 80% of X is neutralized. If the copolymer is highly neutralized (eg, at least 45%, preferably 50%, 55%, 70%, or 80% acid moiety), the MI of the acid copolymer is increased sufficiently to neutralize the resin Of MI at ASTM D-1238, Condition E, 100 ° C., weighing 2160 grams. Preferably, the MI obtained is at least 0.1, preferably at least 0.5, more preferably at least 1.0 or more. Preferably, for highly neutralized copolymers, the MI of the acid copolymer-based resin is at least 20 or at least 40, at least 70, more preferably at least 150.

The acid copolymer is preferably a softening selected from α-olefins, specifically C _3-8 , α, β-ethylenically unsaturated carboxylic acids, specifically acrylic acid and methacrylic acid, and alkyl acrylates and alkyl methacrylates Including monomers, the alkyl group is a copolymer containing 1-8 carbon atoms. “Softening” means that the crystallinity is destroyed (the crystallinity of the polymer is reduced). Although alpha-olefins are alpha-olefins of C ₂ -C _4, ethylene is most preferred when used in the present invention. Therefore, ethylene will be mainly described as the alpha olefin.

  The acid copolymer can be described as an E / X / Y copolymer when the alpha olefin is ethylene, where E is ethylene, X is an α, β-ethylenically unsaturated carboxylic acid, and Y is a softening comonomer. X is preferably present in an amount of 2-30% by weight of the polymer (more preferably 4-20% by weight, most preferably 5-15% by weight). Y is preferably present in an amount of 17-40% by weight of the polymer (more preferably 20-40% by weight, most preferably 24-35% by weight).

  Ethylene acid copolymers with high levels of acid (X) are difficult to prepare for continuous polymerization due to monomer-polymer layer separation. However, the “co-solvent technology” described in US Pat. No. 5,028,674 is employed, or a pressure somewhat greater than the pressure at which a copolymer with low acid can be prepared. Therefore, this difficulty can be avoided.

  Specific acid copolymers are ethylene / (meth) acrylic acid / n-butyl (meth) acrylate, ethylene / (meth) acrylic acid / iso-butyl (meth) acrylate, ethylene / (meth) acrylic acid / methyl (meth). Acrylate and ethylene / (meth) acrylic acid / methyl (meth) acrylate terpolymers.

  The organic acids employed are aliphatic, monofunctional (saturated, unsaturated or polyunsaturated) organic acids, specifically those having less than 36 carbon atoms. Fatty acids or fatty acid salts are preferred. The salt can be any of a wide range, specifically the salts of organic acids barium, lithium, sodium, zinc, bismuth, potassium, strontium, magnesium or calcium. Specific organic acids useful for this invention are caproic acid, caprylic acid, capric acid, lauric acid, stearic acid, behenic acid, erucic acid, oleic acid, and linoleic acid.

  Optional filler elements are selected to adjust the density of the blends of the elements described above, and the selection varies from part to part (eg, cover, antle, core, center, multi-layer core or intermediate layer in a ball), and Different for each type of golf ball desired (eg one piece, two piece, three piece or multi piece ball). This will be described in detail below.

Generally, the filler is an inorganic material having a density greater than about 4 g / cm ³ , preferably greater than 5 g / cm ³ , and is present in an amount between 0 and 60% by weight based on the total weight of the composition. Examples of useful fillers are zinc oxide, barium sulfide, lead silicate, tungsten carbide, and other well-known fillers used in golf balls. The filler material is preferably non-reactive or almost non-reactive and does not harden or increase compression and does not significantly reduce the coefficient of restitution.

An additional optional additive useful in the practice of this invention is an acid copolymer wax (e.g., Allied Wax AC143, which is ethylene / 16-18% acrylic acid coparmer and is considered to have an average molecular weight of 2040. Which helps to prevent reaction between the filler material (e.g. ZnO) and the acid portion of the ethylene coparimer. Other optional additives include a TiO _2, which bleaches, brighteners, surfactants, used as a processing aid.

  The ionomer (HNP type or others) may be blended with conventional ionomer copolymers (di-, ter-, etc.) and the product properties are adjusted to the desired one using well-known techniques. Even after blending, the hardness is still lower and the modulus of elasticity is greater than when blending based on conventional ionomers.

  The ionomer may be blended with a nonionic thermoplastic resin to adjust the product characteristics. Nonionic thermoplastic resins are not limited to these examples, but are based on thermoplastic elastomers such as polyurethane, polyether-ester, poly-amide-ether, polyether-urea, PEBAX (polyether-block-amide). (Commercially available from Atochem), styrene-butadiene-styrene (SBS) block copolymers, styrene (ethylene-butylene) -styrene block copolymers, other polyamides (oligomers or polymers), polyesters, polyolefins (Including PE, PP, E / P coparimer, etc.), ethylene copolymers with various comonomers (for example, vinyl acetate, (meth) acrylate, (meth) acrylic acid, epoxy functionalized monomers, C Etc.), including maleic anhydride-grafted, functionality copolymers with epoxy, etc., elastomers such as EPDM, metallocene catalyzed PE and copolymer, ground powder of thermosetting elastomer, and the like. In such thermoplastic blends, the first thermoplastic material may be from about 1% to about 99% by weight, and the second thermoplastic material may be from about 99% to about 1% by weight. Good.

  In addition, US Pat. No. 6,953,820 and US Pat. No. 6,653,382 discuss high COR compositions made as solid spheres, the disclosures of which are incorporated herein by reference.

The HNP thermoplastic composition of this invention comprises (a) an aliphatic, monofunctional organic acid having less than 36 carbon atoms and (b) an ethylene, α, β-ethylenically unsaturated C _3-8 carboxylic acid copolymer. And more than 90%, preferably close to 100%, and more preferably 100% of all acids of (a) and (b).

The HNP thermoplastic composition described above is preferably melt processable, highly neutralized (greater than 90%, preferably close to 00%, more preferably 100%) (1) addition of softening monomers or other means such as high Ethylene, α, β-ethylenically unsaturated C _3-8 carboxylic acid copolymer disrupted in crystallinity by acid level, (2) non-selected to substantially destroy residual ethylene crystallinity Includes volatile, non-migratory drugs such as polymers of organic acids (or salts). Drugs other than organic acids (or salts) may be used.

  It has been found that modification of an acid copolymer or ionomer with a special organic acid (or salt thereof) can highly neutralize the acid polymer without losing processability or properties such as stretchability and toughness. The organic acids employed in this invention are aliphatic, monofunctional, saturated or unsaturated organic acids, especially those with fewer than 36 carbon atoms, and are non-volatile, non-migratory and ionic array softening And ethylene crystal suppression properties.

  By adding sufficient organic acid, more than 90%, close to 100%, and preferably 100% of the acid portion in the acid copolymer to form the ionomer can be neutralized, with processability and stretch Properties such as strength and toughness are not impaired.

A melt processable, highly neutralized acid copolymer ionomer can be prepared as follows.
(A) (1) an ethylene, α, β-ethylenically unsaturated C _3-8 carboxylic acid copolymer or melt processable ionomer thereof (the ionomer is not neutralizable to an unprocessable or melt-processable level); (1) melt blending one or more aliphatic, monofunctional, saturated or unsaturated organic acids or salts thereof having less than 36 carbon atoms, and simultaneously or sequentially,
(B) an amount of cation source sufficient to increase the neutralization level of all acid moieties (including those in the acid copolymer and in the organic acid) to greater than 90%, preferably close to 100%, more preferably 100%. Add.

Preferably, the highly neutralized thermoplastic material of the present invention is produced as follows.
(A) (1) an ethylene, α, β-ethylenically unsaturated C _3-8 carboxylic acid copolymer or melt processable ionomer thereof, which has been crystallized by adding a softening monomer or other means, (2) A non-volatile, non-migratory organic acid that substantially removes residual ethylene crystallinity is melt blended and simultaneously or sequentially,
(B) The neutralization level of all acid moieties (including the acid moiety in the acid copolymer and, if the non-volatile, non-migratory organic acid is an organic acid) exceeds 90% A sufficient amount of cation source is added, preferably to a level close to 100%, more preferably 100%.

The acid copolymer used to make the ionomer in this invention is preferably a “direct” acid copolymer. The acid copolymers are preferably alpha olefins, specifically C _3-8 , α, β-ethylenically unsaturated carboxylic acids, specifically acrylic acid and methacrylic acid, copolymers. They may optionally include a third softening monomer. “Softening” means that the crystallinity is destroyed (the crystallinity of the polymer is reduced). Suitable “softening” comonomers are softening monomers selected from alkyl acrylates and alkyl methacrylates, wherein the alkyl group contains 1-8 carbon atoms.

  The intermediate layer of the present invention optionally includes a durable low deformation material such as metal, rigid plastic, or a polymer reinforced with high strength organic or inorganic fillers or fibers, or blends or composites thereof. This may be included and will be discussed below. Suitable plastics or polymers include, but are not limited to, high cis- or trans-polybutadiene, one or more partially or fully neutralized ionomers (if the metal ion is a salt of an organic acid) Including those neutralized with the metal ions), polyethylene, polypropylene, polyolefins including polybutylene, and copolymers thereof (including polyethylene acrylic acid or methacrylic acid copolymers) or ethylene and methyl acrylate, Terpolymers of softening acrylate class esters such as n-butyl-acrylate or iso-butyl-acrylate and carboxylic acids such as acrylic acid or methacrylic acid (eg polyethylene-methacrylic acid-n or iso-butyl acrylate) Including methyl acrylate, polyethylene vinyl acetate, terpolymers) containing polyethylene glycidyl acrylate - bets and polyethylene - acrylic acid. Suitable polymers are metallocene catalyzed polyolefins, polyesters, polyamines, nonionic thermoplastic elastomers, copolyether-esters, copolyether-amides, EPR, EPDM, thermoplastic or thermoset polyurethanes, polyureas, polyurethane ionomers, epoxies, Also included are polycarbonate, polybutadiene, polyisoprene, and blends thereof. In the case of metallocene, the polymer may be crosslinked by free radical sources such as peroxides or high irradiation. Suitable polymeric materials are U.S. Patent Nos. 6,187,864, 6,232,400, 6,245,862, 6,290,611, 6,142,887. 5,902,855, and 5,306,760 and those listed in PCT publications WO01 / 29129 and WO00 / 23519.

  Preferably, when the interlayer is made from polybutadiene or other synthetic or natural bomb, the rubber composition is crosslinked to hardness with at least 50 phr of a suitable co-reactant, which is a diacrylate, dimethacrylate, or monomethacrylate. Contains metal salts. Preferably, the co-reactant is zinc diacrylate. Highly cross-linked rubber compounds are discussed in the applicant's patent application entitled No. 10 / 178,580, filed Jul. 20, 2002, entitled “Golf Ball and Method of Controlling Spin Rate”. The contents of the study are incorporated herein by reference.

  If necessary, the golf ball may include a very rigid material, such as a given metal, which, non-limitingly, is tungsten, steel, titanium, chromium, nickel, aluminum, zinc, manganese. Lead, tin, iron, molybdenum, and alloys thereof. Suitable very rigid materials include those listed in US Pat. No. 6,244,977. A filler having a large specific gravity, such as that disclosed in US Pat. No. 6,287,217, may be incorporated into the inner core. Suitable fillers and composites include, but are not limited to, carbon including graphite, glass, aramid, polyester, polyethylene, polypropylene, silicon carbide, boron carbide, natural or artificial silk.

  According to one embodiment of the present invention, a golf ball has at least two core layers, an innermost core, an outer core, and a cover. Preferably, the outer core has a soft, low compression, high COR rubber composition as described above and the inner core has a low strain material as described above. The hard, low strain inner core maintains the optimum level of COR against high club speed deformation, while the elastic outer layer achieves high COR when the club speed is low, Realize the conditions required for play. Thus, the ball of the present invention achieves high initial speed and high COR at high and low club head speeds while maintaining the soft feel and sound desired for green side play.

  The other rubber compound for the outer core may be any low compression, high elasticity polymer, which is a natural rubber containing cis-polyisoprene, trans-polyisoprene, or balata, 1, 2, -Synthetic rubbers including polybutadiene, cis-polybutadiene, trans-polybutadiene, polychloroprene, poly (norbornene), polyoctenamel, polypentenamel, and other diene polymers. The outer core may include multiple layers, such as a laminate, where several thin and soft layers are even laminated together and others.

  If there is a rigid inner core, the flexural modulus is preferably in the range of about 25000 psi to about 250,000 psi. More preferably, the flexural modulus of the rigid inner core is in the range of about 75000 psi to about 225000 psi, and most preferably in the range of about 80000 psi to about 200000 psi. Further, the shore C scale durometer hardness of the rigid inner core is in the range of greater than about 70. The compression of the rigid inner core is preferably greater than about 60 PGA or Atti. More preferably, this compression is greater than about 70, and most preferably greater than about 80. Shore hardness is measured according to ASTM D-2240-00, and flexural modulus is measured approximately two weeks after preparing the test material according to ASTM D6272-98.

  Preferably, the outer core is softer and its compression is smaller than the inner core. Preferably, the outer core has a flexural modulus of about 500 psi to about 25000 psi. More preferably, the flexural modulus is less than about 15000 psi. The hardness of the outer core is preferably from about 25 to about 70 on the Shore C scale. More preferably, the hardness is less than 60 on the Shore C scale.

  One preferred method of achieving the hardness difference between the inner and outer cores is to make the inner core from a non-foamed polymer and the outer core from a foamed polymer selected from the appropriate materials described above. Alternatively, the outer core may be made from a suitable material with reduced specific gravity. In this example, the inner core and outer core may be made from the same polymer or polymeric composition.

  Preferably, the thickness of the outer core layer is about 0.001 inch to about 0.1 inch, preferably about 0.01 inch to about 0.08 inch, and more preferably about 0.03 inch. From about 0.05 inches. Preferably, the overall core diameter is less than about 1.50 inches, preferably less than about 1.45 inches, more preferably from about 0.5 inches to about 1.4 inches. The inner core dimensions may be arbitrary as long as the overall core diameter is the preferred dimensions listed above.

  The cover must be selected from conventional materials that are strong and cut resistant and that are employed as golf ball covers based on the desired performance characteristics. The cover may have one or more layers, for example, an outer cover layer and an inner cover layer. Cover materials such as ionomer resins, blends of ionomer resins, and thermoplastic or thermoset urethanes and ureas may be employed as is known in the art.

  The cover is preferably a resilient, non-decreasing layer. Suitable materials include any material capable of adjusting ball compression, coefficient of restitution, spin rate, and U.S. Pat. Nos. 6,419,535, 6,152,834, 5,919,100. And No. 5,885,172. Ionomers, ionomer blends, thermosetting or thermoplastic polyurethanes, metallocenes, polyurethanes and polyureas (and hybrids thereof) are preferred materials. The cover can be produced by casting methods, reactive injection molding, injection or compression molding, spraying or dipping methods. Preferably, the cover is cast around the core, more preferably the cover is cast around the thick intermediate layer and has polyurea.

  In a preferred embodiment, the golf ball includes an intermediate layer as an outer core layer or inner cover in addition to the outer cover layer. As disclosed in US Pat. Nos. 5,885,172 and 6,132,324, the outer cover layer is made from a soft thermosetting material, such as cast polyurethane or polyurea, and the inner cover is Made from an ionomer material, preferably one containing at least two ionomers.

  When the intermediate layer is an inner cover layer, this is preferably formed from a material with a high flexural modulus, which is currently required when hitting a long shot (eg driver or long iron) Contributes to spin and distance characteristics. Specifically, the Shore D hardness of the inner cover layer is about 55 or greater, preferably about 55-77, and most preferably about 60-70. The flexural modulus of the inner cover layer is at least about 50000 psi, preferably from about 50000 psi to about 150,000 psi, and most preferably from 75000 psi to 125000 psi. In preferred embodiments, the intermediate layer has a thickness of about 0.1 inches to about 0.5 inches, more preferably about 0.11 inches to about 0.12 inches, and most preferably about 0.115 inches to about 0. 119 inches. In other thin layer embodiments, the thickness of the intermediate layer is from about 0.020 inches to about 0.045 inches, more preferably from about 0.030 inches to about 0.040 inches, and most preferably about 0.035 inches. Inches.

  The outer cover layer can be formed from a relatively soft thermoset material to mimic the soft feel and high spin play characteristics of balata balls for “short game” shots. Specifically, the Shore D hardness of the outer cover layer is less than 65, or from about 20 to about 65, preferably from about 30 to about 60, and most preferably from about 35 to about 50. In addition, the material of the outer cover layer must have abrasion resistance suitable for use with the golf ball cover. The outer cover layer of the present invention may comprise any suitable thermosetting material, which is preferably formed from a castable reactive liquid material. Preferred materials for the outer cover layer include, but are not limited to, thermosetting urethanes and polyurethanes, thermosetting urethane ionomers, and thermosetting urethane epoxies. Examples of suitable polyurethane ionomers are disclosed in US Pat. No. 5,692,974, the disclosure of which is hereby incorporated by reference. Thermosetting polyurethanes and polyureas are suitable for the outer cover layer of the balls of this invention. Most preferably, the outer cover layer is a cast urea material.

  According to another embodiment of the invention, the golf ball has a relatively small, low compression, high COR inner core. The diameter of the inner core (or center) is preferably less than or less than 1.40 inches, more preferably from about 0.25 inches to about 1.25 inches, and most preferably from about 0.5 inches to about 1.0 inches. It is. The desired thickness of the core (center) or intermediate layer can be selected in relation to the flexural modulus of the material of each layer and the desired overall compression and deformation of the ball.

  In another embodiment, the inner core is made from a rubber composition containing a halogenated thiophenol as described above. Other polymers suitable for the inner core include polyethylene copolymers, EPR, EPDM, metallocene catalyst polymers, or any material discussed in connection with the outer core described above. However, the preferred compression, hardness and COE must be met. The rubber compound disclosed herein is preferably a high cis- or trans-polybutadiene and has a viscosity of about 40 to about 60 Mooney. Most preferably, the rubber composition is high cis. The hardness of the core is greater than about 70 on the Shore C scale, preferably greater than 80 on the Shore C scale. Also, the core has an Atti compression of less than about 60, preferably less than about 50. The CPR of the generated core is at least about 0.730, more preferably at least about 0.800, and most preferably at least about 0.810, measured at an input speed of 125 ft / s.

  Preferably, the intermediate layer is a low strain polymeric material, such as an ionomer, which is a low and high acid ionomer, an optionally partially or fully neutralized ionomer, or any thermoplastic or thermal Contains a curable polymer. The flexural modulus of the intermediate layer is preferably about 10,000 psi or more, more preferably from about 10,000 psi to about 100,000 psi, and most preferably from about 50,000 psi to about 75000 psi. Other preferred materials are hard, high flexural modulus ionomer resins and blends thereof. In addition, other suitable mantle materials (including core and cover materials) are disclosed in US Pat. No. 5,919,100 and International Publications WO00 / 23519 and WO01 / 29129. One particularly suitable material disclosed in WO01 / 29129 is a hardness neutralized ethylene copolymer and a melt having one or more aliphatic, monofunctional organic acids or salts thereof having less than 36 carbon atoms. It is a processable composition. However, more than 90% of all acids of the ethylene copolymer are neutralized.

  These ionomers are linked to monoolefin polymers in connection with one or more elements selected from the group consisting of unsaturated mono- or di-carboxylic acids having 3 to 12 carbon atoms and esters thereof. (the polymer comprises 1 to 50% of the weight of the unsaturated mono- or di-carboxylic acid and / or its ester). More specifically, the ionomer element of such acid-containing ethylene copolymers comprises an E / X / Y copolymer, where E is ethylene, X is 0-50 weight percent of the softening comonomer such as acrylate or Methacrylate (preferably 0-25 wt.%, Most preferably 0-20 wt.%), Y is 5-35 weight percent of acrylic acid or methacrylic acid (preferably at least about 16 wt.% M, more preferably about 16 wt.%). -35 wt.%, Most preferably about 16-20 wt.%) And the acid moiety is 1-90% (preferably at least about 40%, most preferably at least about 60%) cations such as lithium *, sodium *, Potassium, magnesium *, calcium, barium, lead, tin, zinc *, or aluminum Miniumu, or neutralized by a combination of them to produce a ionomer (indicating that "*" are preferred). Specific acid-containing ethylene copolymers are ethylene / acrylic acid, ethylene / methacrylic acid, ethylene / acrylic acid / n-butyl acrylate, ethylene / methacrylic acid / n-butyl acrylate, ethylene / methacrylic acid / iso-butyl acrylate, ethylene / Acrylic acid / iso-butyl acrylate, ethylene / methacrylic acid / methyl acrylate, ethylene / methacrylic acid / n-butyl methacrylate, ethylene / acrylic acid / methyl methacrylate, ethylene / methacrylic acid / n-butyl methacrylate, ethylene / acrylic acid / Methyl methacrylate, ethylene / acrylic acid / methyl acrylate, ethylene / methacrylic acid / methyl acrylate, ethylene / methacrylic acid / methyl methacrylate, and ethylene / acrylic acid / n Including butyl methacrylate. Preferred acid-containing ethylene copolymers are ethylene / methacrylic acid, ethylene / acrylic acid, ethylene / methacrylic acid / n-butyl acrylate, ethylene / methacrylic acid / methyl acrylate, and ethylene / acrylic acid / methyl acrylate copolymers. The most preferred acid-containing ethylene copolymers are ethylene / methacrylic acid, ethylene / acrylic acid, ethylene / (meth) acrylic acid / n-butyl acrylate, ethylene / (meth) acrylic acid / ethyl acrylate, and ethylene / (meth) acrylic acid / Methyl acrylate copolymer.

  Embodiments of making ionomers are well known in the art as described in US Pat. No. 3,262,272. Such ionomer resins are commercially available from DuPont under the SURLYN ™ trade name and from Exxon under the Iotek ™ trade name. Some particularly suitable SURLYN ™ are SURLYN ™ 8140 (Na) and SURLYN ™ 8546 (Li), which have a methacrylic acid content of about 19%.

The golf balls of the present invention include one-piece, two-piece, multilayer, and wound golf balls with various core structures, intermediate layers, covers and coatings. A golf ball core may be the only single layer with the entire core from the center to the outer perimeter, and may have a center and at least one outer cover layer surrounding it. The innermost part of the center and core is preferably solid, but may be hollow, liquid filled, gel filled or gas filled. The outer core layer may be a solid or a wound layer made from a stretched elastic material. Golf ball covers may include a double cover with one or more layers, eg, an inner and outer cover layer. Optionally, an additional layer may be placed between the core and the cover. In the golf ball of the present invention, at least one layer is produced from a polymer composition having an acid polymer neutralized to hardness with a water vapor transmission rate of 8 g · mil / 100 in ² / day or less. In the most preferred embodiment, the composition of the present invention is present in the relatively thick (0.110 inch or greater) intermediate layer (between the cover and core) of the multi-layer golf ball.

As used herein, a “highly neutralized acid polymer” is at least 70% acid, preferably at least 80%, more preferably at least 90%, more preferably at least 95%, more preferably 100% acid. Refers to the acid polymer after the group has been neutralized. According to this invention, an acid polymer or a partially neutralized acid polymer uses a cation source that is less hydrophilic than the magnesium-based cation source traditionally used to produce HNP. When neutralized to more than 70%, the resulting HNP of the present invention has been found to achieve a composition with improved water vapor transmission. For example, when HNP is produced using a cation source having low hydrophilicity, the water vapor permeability of the polymer composition having HNP is 8 g · mil / 100 in ² / day or less, or 5 g · mil / 100 in ² / day or less, Or 3 g · mil / 100 in ² / day or less, or 2 g · mil / 100 in ² / day or less, 1 g · mil / 100 in ² / day or less, or less than 1 g · mil / 100 in ² / day. As used herein, water vapor transmission rate (MVTR) is given in g · mil / 100 in ² / day, measured at 20 ° C. and complies with ASTM F1249-99.

“Less hydrophilic” is used herein to mean that the cation source is less hydrophilic than a normal magnesium-based cation source. The HNPs of this invention are made using one or more cation sources that are less hydrophilic. Examples of suitable cation sources that are less hydrophilic include, but are not limited to, silicones, silanes, silicic acid derivatives, and complex ligands; rare earth metal ions and compounds; and alkali metals, alkaline earth metals, and Metal ions and compounds with less hydrophilic transition metals; and combinations thereof. Specific cation sources that are less hydrophilic include, but are not limited to, potassium, cesium, calcium, barium, manganese, copper, zinc, tin, and rare earth metal metal ions and compounds. Potassium-based compounds are preferred cation sources with less hydrophilicity, especially E.I. I. Oxane (TM), commercially available from DuPont, is preferred. Oxane is a monopersulfate, where potassium monopersulfate is a compound of the chemical formula 2KHSO ₅ · KHSO ₄ · K ₂ SO ₄ [potassium hydrogen peroxymonosulfate sulfate (5: 3: 2: 2)]. It is an active ingredient that is lost as a salt element. The amount of less hydrophilic cation source can be readily determined based on the desired level of neutralization.

The highly neutralized acid polymers of this invention are α, β-ethylene based unsaturated mono- or dicarboxylic acid homopolymer and copolymer salts, and combinations thereof. The term “copolymer” as used herein includes a polymer comprising two types of monomers, a polymer comprising three types of monomers, and a polymer comprising four or more types of monomers. Preferred α, β-ethylenically unsaturated monocarboxylic or dicarboxylic acids are (meth) acrylic acid, ethacrylic acid, maleic acid, crotonic acid, fumaric acid, itaconic acid. (Meth) acrylic acid is particularly preferred. As used herein, “(meth) acrylic acid” means methacrylic acid and / or acrylic acid. Similarly, “(meth) acrylate” means methacrylate and / or acrylate. Preferred acid polymers are C ₃ to C ₈ α, β-ethylenically unsaturated mono- or dicarboxylic acids and ethylene or C ₃ to C ₆ α-olefins, optionally including a softening monomer. A particularly preferred acid polymer is a copolymer of ethylene and (meth) acrylic acid.

When softening monomers are included, such copolymers are referred to as E / X / Y type copolymers, where E is ethylene and X is a C ₃ to C ₈ α, β-ethylenically unsaturated mono monomer. Carboxylic acid or dicarboxylic acid, Y is a softening monomer. The softening monomer is typically an alkyl (meth) acrylate, where the alkyl group contains 1 to 8 carbon atoms. Preferred E / X / Y type copolymers are those where X is (meth) acrylic acid and / or Y is (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, methyl (meth) acrylate, and ethyl It is a copolymer that is (meth) acrylate. More preferred E / X / Y type copolymers are ethylene / (meth) acrylic acid / n-butyl acrylate, ethylene / (meth) acrylic acid / methyl acrylate, and ethylene / (meth) acrylic acid / ethyl acrylate.

The amount of ethylene or C ₃ to C ₆ α-olefin in the acid copolymer is typically at least 15 wt%, preferably at least 25 wt%, more preferably at least 40 wt%, based on the total weight of the copolymer, More preferably, it is 60 wt%. The amount of C ₃ to C ₈ α, β-ethylenically unsaturated mono- or dicarboxylic acid in the acid copolymer is typically from 1 wt% to 35 wt%, based on the total weight of the copolymer, It is preferably 4 wt% to 35 wt%, more preferably 6 wt% to 35 wt%, and even more preferably 8 wt% to 20 wt%. The amount of optional softening comonomer in the acid copolymer is typically 0 wt% to 50 wt%, based on the total weight of the copolymer.

  Suitable acid polymers also include partially neutralized acid polymers. Examples of suitable partially neutralized acid polymers include, but are not limited to: I. SURLYN ™ ionomers commercially available from DuPont; AClyn ™ ionomers commercially available from Honeywell International; and Iotek ™ ionomers commercially available from Exxon Mobile Chemical. Additional suitable acid polymers are described, for example, in US Pat. No. 6,953,820 and US Patent Application Publication 2005/0049367, the contents of which are hereby incorporated by reference.

  The acid polymer of this invention may be a direct copolymer in which all monomers are added simultaneously to polymerize the polymer, which is described, for example, in US Pat. No. 4,351,931, the contents of which are referred to Incorporate here. Ionomers can be made from direct copolymers as described in US Pat. No. 3,264,272, the contents of which are incorporated herein by reference. Alternatively, the acid polymer of this invention may be a graft copolymer in which monomers are grafted onto an existing polymer, as described, for example, in US Patent Application Publication 2002/0013413, the contents of which are referred to. Here.

  The composition of the present invention is preferably for an intermediate layer, and includes at least one HNP according to the invention (i.e., produced using a less hydrophilic cation source) and optional one or more additional Contains HNP. If additional HNP is included, the additional HNP is one or more HNPs according to the invention and / or one or more normal HNPs (ie produced using a normal cation source) Good. The total amount of HNP in the composition is preferably at least 30 wt%, more preferably at least 50 wt%, and preferably 50 wt% to 99.5 wt%, more preferably 60 wt%, based on the total weight of the polymer of the composition. % To 98 wt%. Preferably the amount of HNP according to the invention is at least 30 wt% in the composition.

  In order to be processable, the melt flow index of the ionomer-containing composition of this invention is at least 0.5 g / 10 min. Preferably, the melt flow index of the HNP-containing composition is from 0.5 g / 10 min to 100.0 g / 10 min, more preferably from 1.0 g / 10 min to 10.0 g / 10 min, and even more preferably 1.0 g / 10 minutes to 5.0 g / 10 minutes, more preferably 1.0 g / 10 minutes to 4.0 g / 10 minutes.

  The composition of the present invention may optionally include one or more melt flow modifiers. Suitable melt flow modifiers include organic acids and salts thereof, polyamides, polyesters, polyacrylates, polyurethanes, polyethers, thermoplastic polyureas, polyhydric alcohols, and combinations thereof. Suitable organic acids are aliphatic organic acids, aromatic organic acids, saturated monofunctional organic acids, unsaturated monofunctional organic acids, multiunsaturated monofunctional organic acids, and dimer derivatives thereof. Specific examples of suitable organic acids include, but are not limited to, caproic acid, caprylic acid, capric acid, lauric acid, stearic acid, behenic acid, erucic acid, oleic acid, linoleic acid, myristic acid, benzoic acid, Including palmitic acid, phenylacetic acid, naphthalenic acid, and dimer derivatives thereof. When the composition of this invention includes one or more organic acid salts, the cation source used to produce the organic acid salt is preferably a cation source with less hydrophilicity. Suitable organic acids are described in more detail, for example, in US Pat. No. 6,756,436, the contents of which are hereby incorporated by reference.

  Additional non-fatty acid melt flow modifiers suitable for use in the compositions of this invention include those described in U.S. Patent Application Nos. 11/216725 and 11/216726, the disclosures of which are incorporated herein by reference. Incorporate here.

The composition of the present invention may include one or more additives in an amount of 0 wt% to 60 wt%, based on the total weight of the composition. Suitable additives include, but are not limited to, chemical expansion and foaming agents, optical brighteners, colorants, fluorescent agents, whitening agents, UV absorbers, light stabilizers, antifoaming agents, processing aids, mica, talc, nano-fillers, antioxidants, stabilizers, softening agents, perfume ingredients, plasticizers, impact modifiers, TiO _2, acid copolymer wax, surfactants, and fillers, such as zinc oxide, tin oxide, Includes barium sulfate, zinc sulfate, calcium oxide, calcium carbonate, zinc carbonate, barium carbonate, clay, tungsten, tungsten carbide, silica, zinc silicate, liglind (recycled material), and mixtures thereof. Suitable additives are fully described, for example, in US Patent Application Publication 2003/0225197, incorporated herein by reference.

The intermediate layer may optionally be prepared by blending the HNP of the present invention with one or more additional polymers, such as thermoplastic polymers and elastomers. Examples of thermoplastic polymers suitable for blending with the HNP of this invention include, but are not limited to, polyolefins, polyamides, polyesters, polyethers, polycarbonates, polysulfones, polyacetals, polylactones, acrylonitrile-butadiene-styrene resins, polyphenylene oxides. , Polyphenylene sulfide, styrene-acrylonitrile resin, styrene maleic anhydride, polyimide, aromatic polyketone, ionomer and ionomer precursor, acid copolymer, conventional HNP, polyurethane, grafted or ungrafted metallocene catalyst polymer, single site catalyst polymerization Polymers, highly crystalline acid polymers, cationic ionomers, and combinations thereof. Specific polyolefins suitable for blending one or more linear or branched or cyclic _C 2 _{-C 40} olefin, specifically, of one or more _C 2 _{-C 40 olefins,} the C 3 _{-C 20} It is a polymer containing ethylene or propylene copolymerized with an α-olefin or a C ₃ -C ₁₀ α-olefin. Specific conventional HNPs suitable for blending include, but are not limited to, one or more HNPs disclosed in US Pat. Nos. 6,756,436, 6,894,098, and 6,953,820, the disclosure of which Are incorporated herein by reference. Examples of elastomers suitable for blending with the polymers of this invention include, but are not limited to, all natural and synthetic rubbers, ethylene propylene rubber ("EPR"), ethylene propylene diene rubber ("EPDM"), Styrene block copolymer rubber (eg, SI, SIS, SB, SBS, SIBS, etc., “S” is styrene, “I” is isobutylene, “B” is butadiene), butyl rubber, halobutyl rubber, isobutylene and para-alkyl Copolymers of styrene, halogenated copolymers of isobutylene and para-alkylstyrene, natural rubber, polyisoprene, copolymers of butadiene with acrylonitrile, polychloroprene, alkyl acrylate rubber, isoprene chloride rubber, acrylonitrile isoprene chloride Beam, and a polybutadiene rubber (cis and trans). Still other suitable blend polymers include those disclosed in US Pat. No. 5,981,658, eg, column 14, lines 30-56, the contents of which are incorporated herein by reference. The blends described herein can be made by combining the reactor in series with the reactor blend by blending after the reactor, and by producing multiple types of polymers using multiple catalysts in the same reactor, Can be manufactured. The polymer may be mixed before entering the extruder or may be mixed in the extruder.

  The flexural modulus of the interlayers of this invention is typically from 3000 psi to 200000 psi, preferably from 5000 psi to 150,000 psi, more preferably from 10,000 psi to 125000 psi, and even more preferably from 50,000 psi to 750,000 psi. The material hardness of the composition is generally from 30 Shore D to 80 Shore D. In embodiments where the composition is in the center of a golf ball, the material hardness is preferably 30 Shore D to 50 Shore D. In embodiments where the composition is in a golf ball cover layer, outer core layer or intermediate layer between the core and cover, the material hardness is preferably 30 Shore D to 70 Shore D. The notched Izod impact strength of the compositions of this invention is generally at least 2 ft · lb / in measured at 23 ° C. according to ASTM D256.

  The present invention is not limited to a specific method or apparatus for producing the composition. In the preferred embodiment, it is prepared by the following process. An acid polymer, preferably ethylene / (meth) acrylic acid, is fed to a melt extruder, such as a single or twin screw extruder. An appropriate amount of a less hydrophilic cation source is added to the molten acid polymer. The acid polymer may be partially neutralized prior to contact with a cation source, preferably a cation source selected from calcium, magnesium and zinc metal salts and compounds. The acid polymer / cation mixture is intensively mixed before it is extruded as a strand from the mold head. Optionally, a less hydrophilic cation source based on a fatty acid salt or non-fatty acid salt flow modifier is introduced during HNP generation. In a specific aspect of this invention, the ethylene / (meth) acrylic acid copolymer is prepared from E. I. Nuclel ™ acid copolymers commercially available from DuPont (eg, Nuclel 960. Ethylene / methacrylic acid copolymer) and Primacor ™ polymers (eg, Primacor XUS 60758.08L and XUS 60751) commercially available from Dow Chemical. 18. Ethylene / acrylic acid copolymer containing 13.5% and 15.0% acid respectively).

  Other materials suitable for the intermediate layer (a thick intermediate layer disposed between the core and cover, or alternatively, typically a relatively thin inner cover layer) are at least about 50 on the Shore D scale. A highly rigid and highly neutralized ionomer with durometer hardness and flexural modulus of at least about 150,000 psi. The range of flexural modulus is about 50,000 psi to about 150,000 psi. The hardness ranges from about 55 to about 80 Shore D, more preferably from about 55 to about 70 Shore D. The ionomer, preferably at least two ionomers, may be blended with a low neutralization ionomer having an acid content of 5 to 25%, and blended with a non-ionomer polymer or compatibilizer (eg, glycidyl or maleic anhydride). You can do it. However, the preferred hardness and flexural modulus must be met. Highly neutralized ionomers are disclosed in the Applicant's patent application publication 2003/0013549, which is incorporated herein by reference.

  In one preferred embodiment, this suitable material is a highly neutralized polymer with a fatty acid salt, such as a highly neutralized copolymer and an aliphatic, monofunctional, one or more carbon atoms of less than 36. A melt-processable composition having an organic acid or salt thereof and neutralizing more than 90% of all acids of the ethylene copolymer, and a rigid, partially neutralized ionomer, such as SURLYN ( Trademarks) commercially available as 8945, 7940, 8140, and 9120, and blends with others. The blend has a hardness range of about 65 to 75 on the Shore D scale.

  The intermediate layer has a laminated layer if necessary. For example, the intermediate layer may comprise a laminate having the following four layers. That is, a polyamide layer having a flexural modulus of about 200,000 psi, a terpolymer ionomer or non-neutralized acid terpolymer having a flexural modulus of about 30000 psi, a polyamide layer having a flexural modulus of about 60000 psi, a low acid ionomer, and a flexural modulus of about It is a 70,000 psi high acid ionomer. The composite flexural modulus of the four-layer laminate is about 90000 psi, ie, roughly the average of the flexural modulus of the four layers, assuming that each layer has the same thickness.

  In a preferred embodiment, if there is an inner core, the diameter of the inner core is about 0.800 inches to 1.400 inches, more preferably 1.3 inches to about 1.4 inches. Is about 44 or less, and its COR is about 0.800. The intermediate layer has at least two ionomers, has a flexural modulus of greater than about 50,000 psi and a thickness of at least about 0.110 inches, more preferably from about 0.11 inches to about 0.12 inches. The cover is preferably cast polyurethane or polyurea and has a hardness of about 40 to about 60 Shore D. The compression of the core is preferably about 44 or less, and the combination of core and interlayer has a compression of about 70 to about 100.

  The core is preferably a single solid layer. Alternatively, the core may have multiple layers. Preferably, the diameter is about 1.400 inches or less, more preferably between about 0.8 inches and about 1.4 inches, and most preferably between about 1.3 inches and about 1.4 inches. . The core has a COR of about 0.770 or more, more preferably about 0.800 or more, most preferably about 0.820 or more, and the ball has a COR of at least 0.800, more preferably about 0.805. To about 0.820. In one preferred embodiment, the core has a COR of about 0.770 to about 0.810.

  In the preferred embodiment, the intermediate cover layer and the outer cover layer are similar to the inner cover layer and the outer cover layer of the cover, respectively, in order to achieve gradual performance. For example, the outer cover layer is made from a soft thermoset polymer, such as cast polyurea, and the intermediate cover layer is a rigid ionomer or similar that has a hardness of at least 55 on the Shore D scale and a flexural modulus of at least 55000 psi. Manufactured from the composition.

  The overall thickness of the cover is preferably less than 0.125 inches. The innermost layer is preferably about 0.005 inches to about 0.100 inches, more preferably about 0.010 inches to about 0.090 inches, and most preferably about 0.015 inches to about 0.070 inches. It is. The thickness of the intermediate cover layer is preferably from about 0.010 inch to about 0.050 inch, and the thickness of the outer cover layer is preferably from about 0.020 inch to about 0.040 inch.

  The compression of golf balls made in accordance with the present invention and disclosed above is greater than about 60 PGA, more preferably greater than about 80 PGA, and even more preferably greater than about 90 GPA. These balls achieve a COR of at least 0.80, more preferably 0.81 at 125 ft / s. These balls achieve a COR of at least 0.75, more preferably 0.76 at 160 ft / s.

  All patents and patent applications cited herein are hereby expressly incorporated by reference.

  It should be noted that the invention described herein and set forth in the claims is not limited to the specific embodiments disclosed herein. This is because these examples are only intended to illustrate some aspects of the present invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those disclosed and shown herein will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the claims.

Claims (5)

A core having a diameter of 1.27 cm (0.5 inches) to 3.56 cm (1.4 inches), a compression of about 45 or less, and a coefficient of restitution of 0.730 to 0.810;
A cast polyurea cover;
Manufactured from a composition that is placed between the core and the cover and has a thickness of 0.279 cm (0.11 inches) or more, a highly neutralized water vapor transmission rate of 8 g · mil / 100 in ² / day or less An intermediate layer,
When the combination of the core and the intermediate layer achieves compression of about 70 to about 100, and the coefficient of restitution of the golf ball is measured at an input speed of 38.1 m / s (125 ft / s), 0.805 To 0.820, and when measured at an input speed of 48.8 m / s (160 ft / s), it is 0.75 or more, and the compression of the golf ball is 75 to 105 Golf ball.   The golf ball of claim 1, wherein the core has a diameter of 1.3 inches to 1.4 inches.   The golf ball of claim 1, wherein the intermediate layer has a hardness of 55 Shore D to 70 Shore D.   The golf ball of claim 1, wherein the cast polyurea cover has a hardness of 40 Shore D to 60 Shore D.   The golf ball according to claim 1, wherein a coefficient of restitution of the combination of the intermediate layer and the core is 0.810 to 0.820 when measured at an input speed of 38.1 m / s (125 ft / s).