JP2009034519A - Negative hardness gradient inner core for dual core golf ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a single layer core that has a soft-to-hard gradient from the surface to the center in a golf ball, and to achieve a method of producing such a core efficiently and at a low cost. <P>SOLUTION: The golf ball has an inner core having a first outer surface and a geometric center and being formed from a substantially homogenous formulation such that the inner core has a hardness of 45 Shore C to 65 Shore C, and an outer core layer disposed about the inner core, having a second outer surface and an inner surface and being formed from a substantially homogenous formulation such that the outer core layer has a hardness of 55 Shore C to 90 Shore C. A cover layer is disposed about the outer core layer. The hardness of the first outer surface is the same as or lower than the hardness of the geometric center to define a "negative hardness gradient" and the hardness of the second outer surface is greater than the hardness of the inner surface to define a "positive hardness gradient". <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  This invention relates generally to golf balls with a core, and more specifically to a single layer core with a surface hardness equal to or less than the center hardness.

  Solid golf balls are typically manufactured from a solid core encapsulated by a cover, both the solid core and the cover may have multiple layers, for example, a dual core comprises a solid center and an outer core layer. The multi-layer cover also has an inner layer. In general, golf ball cores and / or centers are constructed from compositions based on thermoset rubber, typically polybutadiene. The core is typically heated and cross-linked to achieve a predetermined property, such as greater or lesser compression, which affects the spin rate and / or better “feel” of the ball. These and other features may be fine-tuned according to the demands of golfers of various skills. From the golf ball manufacturer's point of view, it is desirable for the core to achieve a wide range of properties, such as elasticity, durability, spin, and “feel”. This allows manufacturers to manufacture and sell many different types of golf balls adapted to different levels of workmanship.

  Traditionally, many single core golf balls are known as “positive hardness gradients” with a conventional hardness gradient that goes from hard to soft from the core surface to the center of the core. The patent literature includes a number of literature that examines the hardness gradient across the golf ball from a hard surface to a soft center.

  U.S. Pat. No. 4,650,193 (Molitor et al., US Pat. No. 5,697,097) treats a curable elastomeric slag with a curing modifier and then molds the slag into a core to form a core surface layer. To provide a hardness gradient. This treatment is alleged to provide the core with two regions of different composition, the first part being the hard, resilient, central part of the core, which remains untreated, Section 2 is the outer layer of the core, which is soft and easy to deform, which has been treated with a core modifier. The two “layers” or regions of the core are integral with each other, resulting in a gradient effect from a soft surface to a hard center.

  U.S. Pat. No. 3,784,209 (Berman et al., U.S. Pat. No. 5,677,097) generally discloses a hardness gradient from soft to hard. The “209” patent discloses a non-uniform molded golf ball using a “mixed” elastomer core. The uncured central sphere is surrounded by a compatible but different uncured elastomer. The two layers of elastomer are simultaneously exposed to the curing agent and become integral with each other, thereby forming a mixed core. The core center is stiffer with a greater density of the first elastomer material than the outer layer. One drawback of this manufacturing method is the time-consuming process of forming the first elastomer, then forming the second elastomer, and then molding the two together. .

  Other patents consider cores that accept surface treatments that achieve a soft “skin”. However, because the internal parts of these cores are untreated, they are accompanied by a gradient from a hard surface to a soft center similar to conventional cores. For example, U.S. Pat. No. 6,113,831 (Nesbitt et al., US Pat. No. 5,677,086) discloses a generally conventional core and a separate soft skin that wraps around the core. This soft skin is formed by exposing the base material slag to the stream during the molding process such that the maximum molding temperature exceeds the stream set temperature, and controlling the exothermic molding temperature during molding. This skin has the outermost 1/32 inch to 1/4 inch in the radial direction of the spherical core. US Pat. Nos. 5,976,443 and 5,733,206 (both Nesbitt et al., Patent Documents 4 and 5) give water mist to the surface of the slag to form a soft skin before molding. Is disclosed. Allegedly, water delays cross-linking of the core surface, thereby forming a softer skin around the hard central portion, thereby softening the core compression.

  In addition, many patents disclose multi-layer golf ball cores, where each core layer has a different hardness, thereby creating a hardness gradient from one core layer to another two core layers.

However, it is possible to realize a single-layer core with a gradient that becomes softer and harder (“negative” gradient) from the surface to the center, and to realize an inexpensive and efficient method for manufacturing such a core. Still desired. A core having such properties allows golf ball designers to produce products with a unique combination of compression, “feel”, and spin.
US Pat. No. 4,650,193 US Pat. No. 3,784,209 US Pat. No. 6,113,831 US Pat. No. 5,976,443 US Pat. No. 5,733,206

  The present invention is a first formulation that is an inner core and includes a first outer surface and a geometric center, the hardness of which is substantially uniform throughout such that its hardness is in the range of 45 Shore C to 65 Shore C. Said inner core manufactured from; and an outer core layer disposed around said inner core, with a second outer surface and an inner surface, manufactured as a whole from a second substantially uniform formulation And is directed to a golf ball having the outer core layer having a hardness of 55 Shore C to 90 Shore C. A cover layer is disposed around the outer core layer. The hardness of the first outer surface is equal to or less than the hardness of the geometric center and forms a “negative hardness gradient”, and the hardness of the second outer surface is the inner surface A “positive hardness gradient” is formed.

  The inner core has a metal salt of a carboxylic acid in an amount of about 15 phr to about 30 phr, and about 0 when the ratio of antioxidant to initiator of the inner core is normalized to 100% activity. .40 or more, preferably about 0.50 or more, and the outer core layer has a metal salt of carboxylic acid in an amount of about 30 phr to about 45 phr. The initiator is typically 100% active and is present in an amount from about 0.25 phr to about 5.0 phr, and the antioxidant is typically in an amount from about 0.2 phr to about 1 phr. Only exist.

  In one embodiment, the hardness of the first outer surface is 42 Shore C to 60 Shore C, the hardness of the geometric center is 52 Shore C to 65 Shore C, and the magnitude of the “negative hardness gradient” is About 0 to -10. In another embodiment, the hardness of the second outer surface is 62 Shore C to 89 Shore C, the hardness of the inner surface is 58 Shore C to 82 Shore C, and the magnitude of the “positive hardness gradient” Is 10 to 20. Preferably, the outer diameter of the inner core is from 0.75 inches to 1.4 inches and the outer diameter of the outer core layer is from 1.5 inches to 1.59 inches. The cover layer typically has an inner cover layer and an outer cover layer. The inner core and outer core layers may be made from a diene rubber composition and optionally include softening and speeding agents (soft and fast agents).

  The present invention also includes an inner core comprising a first outer surface and a geometric center, the first substantially substantially uniform throughout, such that its hardness is in the range of 60 Shore C to 90 Shore C. Said inner core made from a formulation of: a second outer surface and an inner surface, a second substantially uniform throughout, such that its hardness is in the range of 45 Shore C to 70 Shore C An outer core layer made from a formulation of; and a cover layer. The geometric center, the first and second outer surfaces, and the inner surface each have a hardness. The hardness of the first outer surface is equal to or less than the hardness of the geometric center and forms a “negative hardness gradient”, and the hardness of the second outer surface is the inner surface A “positive hardness gradient” is formed.

  In one example, the inner core had a metal salt of a carboxylic acid in an amount of about 30 phr to about 45 phr, and the ratio of the inner core antioxidant to the initiator was normalized to 100% activity. Sometimes about 0.40 or more, preferably about 0.50 or more, and the outer core layer has a metal salt of carboxylic acid in an amount of about 15 phr to about 30 phr. The initiator is typically present in an amount of about 0.25 phr to about 5.0 phr under 100% activity and the antioxidant is present in an amount of about 0.2 phr to about 1 phr.

  In one embodiment, the hardness of the first outer surface is 61 Shore C to 83 Shore C, the hardness at the geometric center is 65 Shore C to 86 Shore C, and the magnitude of the “negative hardness gradient” is from 0 -10. In an alternative embodiment, the hardness of the second outer surface is 52 Shore C to 68 Shore C, the hardness of the inner surface is 49 Shore C to 63 Shore C, and the magnitude of the “positive hardness gradient” is About 10 to 20. Typically, the outer diameter of the inner core is 0.75 to 1.4 inches, and the outer diameter of the outer core layer is 1.5 inches to 1.59 inches. Preferably the cover layer has an inner cover layer and an outer cover layer. The inner core and outer core layers are typically made from a diene rubber composition and optionally include a softening and speeding agent.

  The present invention further includes an inner core comprising a first outer surface and a geometric center, the first substantially substantially uniform throughout, such that its hardness is in the range of 40 Shore C to 80 Shore C. Are directed to golf balls, including those made from the formulation. The outer core layer is formed around the inner core, has a second outer surface and an inner surface, and has a substantially uniform second thickness throughout, such that its hardness is in the range of 60 Shore C to 90 Shore C. Manufactured from two formulations. A cover layer comprising at least two layers is formed around the outer core layer.

  The hardness of the first outer surface is equal to or less than the hardness of the geometric center to form a “negative hardness gradient”, and the hardness of the second outer surface is greater than the hardness of the inner surface and is “positive hardness” A slope "is formed, whereby the hardness of the inner surface and the first outer surface is the same, and they are less than the hardness of the geometric center and the hardness of the second outer surface. The inner core and outer core layers typically comprise a diene rubber composition and optionally a softening and speeding agent.

  The golf balls of the present invention may include single-layer (one-piece) golf balls and multi-layer golf balls, such as golf balls with a core and a cover surrounding the core, but preferably a solid center (also known as the inner core). And a core having an outer core layer, an inner cover layer, and an outer cover layer. Of course, either the core and / or the cover layer may include multiple layers. In a preferred embodiment, the core is manufactured from an inner core and an outer core, the inner core and outer core layer being the innermost portion from the outer surface of each element (ie, the center of the inner core or the inner surface of the outer core layer). Although there is a “soft to hard” hardness gradient (“negative” hardness gradient) radially inward, alternative embodiments may be envisaged that change the direction and combination of hardness gradients between core elements. (For example, a “negative” gradient in the center but a “positive” gradient in the outer core layer, or vice versa).

  The center of the core may be a liquid-filled or hollow sphere surrounded by one or more intermediate and / or cover layers, or a solid or liquid wrapped around a tensioned elastic material It may be the center. Any layer disposed around these alternative centers may be accompanied by the hardness gradient (ie, “negative”) of the core of the present invention. The cover layer may be formed from a single layer or, for example, a plurality of layers, specifically an inner cover layer and an outer cover layer.

  As briefly discussed above, in the core of the present invention, the hardness gradient is measured in hardness on the surface of the inner core (or outer core layer) and radially to the center of the inner core, typically 2 mm. Defined by hardness measurements made in increments of. As used herein, the terms “negative” and “positive” refer to the innermost portion of the element being measured (eg, the center of the inner core in a solid core or dual core structure; the inner surface of the core layer; other ) Hardness value is subtracted from the hardness value of the outer surface of the element being measured (eg, the outer surface of the solid core; the outer surface of the inner core in the dual core; the outer surface of the outer core layer in the dual core, etc.) Results. For example, if the hardness value of the outer surface of the solid core is less than the center (ie, the surface is softer than the center), the hardness gradient is considered a “negative” gradient (small number−large number = negative number). The core of the present invention preferably has a zero or negative hardness gradient, more preferably between zero (0) and -10, most preferably between 0 and -5.

  Preferably, the core layer (inner core or outer core layer) is made from a composition comprising at least one thermoset base rubber, for example polybutadiene rubber, which comprises at least one peroxide and at least one reactive. Cured with a coagent, which may be an unsaturated carboxylic acid, such as a metal salt of acrylic acid or methacrylic acid, a non-metallic coagent, or a mixture thereof. Preferably, a suitable antioxidant is included in the composition. Optional softening and speeding agents (and often cis-to-trans catalysts), such as organic sulfur or metal-containing organic sulfur or rods, may also be included in the core formulation.

  Other ingredients known to those skilled in the art may be used, including but not limited to density adjusting fillers, processing aids, plasticizers, foaming agents or foaming agents, sulfur accelerators, and / or non-peroxidation. It can be understood to include a radical source.

  The base thermoset rubber may be blended with other rubbers and polymers and typically includes natural rubber or synthetic rubber. A preferred base rubber is 1,4-polybutadiene with a cis structure of at least 40%, preferably more than 80%, more preferably more than 90%.

  Examples of desired polybutadiene rubbers include BUNA ™ CB22 and BUNA ™ CB23, commercially available from LANXESS; UBEPOL ™ 360L, commercially available from UBE Industry, Tokyo, Japan; UBEPOL ™ 150L and UBEPOL-BR rubber; KINEX ™ 7245 available from Goodyear, Akron, Ohio; SE BR-1220 and TAKTENE ™ 1203G1,220 commercially available from Dow Chemical, And 221; Europrene (TM) NEOCIS (TM) BR40 and BR60 commercially available from Polymeri Europa; and Japan Synthetic Rubber BR 01 commercially available, BR 730, BR 11, and BR 51; PETROFLEX (TM) BRNd-40; and Karbochem Inc. from commercially available KABOCHEM (TM) ND40, ND45, and a ND60.

  The base rubber may have a Mooney viscosity high or medium rubber, or a blend thereof. The “Mooney” unit refers to the 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.

  The range of Mooney viscosity is preferably greater than about 40, more preferably in the range of about 40 to about 80, and even more preferably in the range of about 40 to about 60. Polybutadiene rubber having a higher Mooney viscosity may be used. However, it is a condition that the viscosity of the polybutadiene does not reach a level where the high viscosity polybutadiene is clogged or otherwise adversely affects the production machine. It can be understood that polybutadiene having a viscosity of less than 65 Mooney can be used in the present invention.

  In one embodiment of the present invention, a golf ball core made from a medium to high Mooney viscosity polybutadiene material achieves great resilience (and thus a large distance) without increasing the hardness of the ball. Such cores are soft, i.e., compression is less than about 60, more specifically in the range of about 50-55. Cores with compression in the range of about 30 to about 50 are also within the scope of such preferred embodiments.

  Suitable medium or high Mooney viscosity polybutadiene commercial resources include Bayer AG CB23 (Nd catalyst) and Shell 1220 (cocatalyst), the former with Mooney viscosity around 50 and linear vegetable polybutadiene in hardness. It is. When desired, the polybutadiene may be mixed with other elastomers known in the art, such as other polybutadiene rubber, natural rubber, styrene butadiene rubber, and / or isoprene rubber to modify the properties of the core. When using a mixture of elastomers, the amount of other components in the core composition is typically based on 100 parts by weight of the total amount of the elastomer mixture.

  In one embodiment, the base rubber comprises Nd catalyzed polybutadiene, rare earth catalyzed polybutadiene rubber, or a blend thereof. When desired, the polybutadiene may be mixed with other elastomers known in the art, such as natural rubber, polyisoprene rubber, and / or styrene butadiene rubber to modify the properties of the core. Other suitable base rubbers include thermosetting materials such as ethylene propylene diene monomer rubber, ethylene propylene rubber, butyl rubber, halobutyl rubber, hydrogenated nitrile butadiene rubber, nitrile rubber, and silicone rubber.

  A thermoplastic elastomer (TPE) may be mixed with a base thermoset rubber to modify the properties of the core layer or uncured core layer stock. These PTEs are natural or synthetic rubbers, or high trans-polyisoprene, high trans-polybutadiene, or any styrene block copolymer, such as styrene ethylene butadiene styrene, styrene-isoprene-styrene, metallocene or other single site catalyzed polyolefins For example, styrene-octene, or ethylene-butene, or thermoplastic polyurethane (TPU), which includes, for example, copolymers with silicone. Other TPEs suitable for mixing with the thermoset rubbers of this invention are considered to have polyetheramide copolymers, PEBAX ™, polyetherester copolymers, HYTEL ™, which are believed to have thermoplastic urethanes. ), And KRATON ™, which is believed to have a styrene block copolymer elastomer. Any of the TPEs or TPUs described above contain functional groups suitable for grafting and include maleic acid or maleic anhydride.

  Additional polymers may optionally be incorporated into the base rubber. Examples of such include, but are not limited to, thermosetting elastomers such as core liglins, thermoplastic vulcanizates, copolymeric ionomers, terpolymeric ionomers, polycarbonates, polyamides, copolymeric polyamides, polyesters, polyvinyl alcohol, acrylonitrile-butadiene- Styrene copolymer, polyarylate, polyacrylate, polyphenylene ether, impact modified polyphenylene ether, high impact polystyrene, diallyl phthalate polymer, styrene-acrylonitrile polymer (SAN) (including olefin modified SAN and acrylonitrile-styrene-acrylonitrile polymer) , Styrene-maleic anhydride copolymer, styrene copolymer, functional styrene copolymer, functional styrene terpoly Chromatography, styrene terpolymers, cellulose polymers, liquid crystal polymers, ethylene - vinyl acetate copolymer, polyurea and polysiloxane or these species metallocene-catalyzed polymers.

  Polyamides suitable for use as additional polymer materials in compositions within the scope of this invention include resins obtained as follows. (1) As (a) dicarboxylic acid such as succinic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, or 1,4-cyclohexanedicarboxylic acid, (b) diamine such as ethylenediamine, tetraethylenediamine, pentamethylenediamine, hexamethylene Polymerization is carried out with diamine, decamethylenediamine, 1,4-cyclohexylamine or m-xylylenediamine. As (2), ring-opening polymerization of a cyclic lactam such as epsilon caprolactam or omega laurolactam is performed. As (3), an aminocarboxylic acid such as 6-aminocaproic acid, 9-aminocaproic acid, 11-aminocaproic acid or 12-aminocaproic acid is polymerized. Alternatively, as (4), a cyclic lactam is copolymerized with a dicarboxylic acid and a diamine. Specific examples of suitable polyamides are NYLON6, NYLON66, NYLON610, NYLON11, NYLON12, copolymers NYLON, NYLONMXD6 and NYLON46.

  Suitable peroxide initiators are dicumyl peroxide; 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne 2,5-dimethyl-2,5-di (benzoylperoxy) hexane; 2,2'-bis (t-butylperoxy) -di-iso-propylbenzene; 1,1-bis (t-butylperoxy)- 3,3,5-trimethylcyclohexane; n-butyl-4,4-bis (t-butylperoxy) valerate; t-butylperbenzoate; benzoyl peroxide; n-butyl-4,4′-bis (butylperoxy) valerate Di-t-butyl peroxide; or 2,5-di- (t-butylperoxy) -2,5-dimethylhexane, lauryl peroxide; - including - (peroxy isopropyl 2-t-butyl) benzene, di -t- butyl peroxide butyl hydroperoxide, alpha-alpha-bis (t-butylperoxy) di-isopropyl propyl benzene, di. Preferably, the rubber composition comprises from about 0.25 to about 5.0 parts by weight (phr) of peroxide, more preferably from 0.5 phr to 3 phr, and most preferably from 0.1 to 100 parts by weight of rubber. Contains 5 phr to 1.5 phr peroxide. In the most preferred embodiment, the peroxide is present in an amount of about 0.8 phr. These ranges of peroxide are given under the assumption that the peroxide is 100% active and does not take into account any carriers that may be present. Since many commercially available peroxides are sold with a carrier compound, the actual abundance of active peroxide must be calculated. Commercially available peroxide initiators are dicumyl peroxide (DICUP ™ R, DICUP ™ 40C and DICUP ™ 40KE) of the DICUP ™ family available from Cropton (Geo Specialty Chemicals). )including. Similar initiators are described in AcroChem, Luxess, Flexsys / Haewick, and R.C. T.A. Available from Vanderbilt. Another commercially available and preferred initiator is TRIGONOX ™ 265-50B from Akzo Nobel, which is 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, and Di (2-t-butylperoxyisopropyl) benzene. TRIPONOX ™ peroxide is sold with a carrier compound.

  Suitable reactive coagents include, but are not limited to, metal salts of diacrylates, dimethacrylates, and monomethacrylates, suitable for use in the present invention are metals that are zinc, manganese, calcium, barium, Those that are tin, aluminum, lithium, sodium, potassium, iron, zirconium, and bismuth. Although zinc diacrylate (ZDA) is preferred, the invention is not so limited. ZDA imparts a large initial velocity to the golf ball. DZA can be of various purity grades. In order to realize the object of the present invention, the ZDA purity increases as the amount of zinc stearate present in the ZDA is small. ZDA containing less than about 10% zinc stearate is preferred. Further preferred is ZDA containing only about 4-8% zinc stearate. Suitable commercially available zinc diacrylates include those available from Sartmer. Preferred concentrations of ZDA available are from about 10 phr to about 40 phr, more preferably from about 20 phr to about 35 phr, and most preferably from about 25 phr to about 35 phr. In a specific preferred embodiment, the reactive coagent is present in an amount from about 29 phr to about 31 phr.

  Additional preferred coagents that may be utilized alone or in combination with those described above include, but are not limited to, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and others. Those skilled in the art will appreciate that when the coagent is a liquid at room temperature, advantageously, these compounds can be dispersed on a suitable carrier for easier integration into the rubber mixture. .

  Antioxidants are compounds that prevent oxidative breakdown of elastomers and / or prevent reactions promoted by oxygen radicals. Some exemplary antioxidants that can be utilized in this invention include, but are not limited to, quinoline-type antioxidants, amine-type antioxidants, and phenol-type antioxidants. Preferred antioxidants are R.I. T.A. 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol) available as VANOX ™ MBPC from Vanderbilt. Other polyphenolic antioxidants include VANOX (TM) T, VANOX (TM) L, VANOX (TM) SKT, VANOX (TM) SWP, VANOX (TM) 13, and VANOX (TM) 1290.

  Suitable antioxidants include, but are not limited to, alkylene-bis-alkyl substituted cresols such as 4,4′-methylene-bis (2,5-xylenol); 4,4′-ethylidene-bis- (6- 4,4′-butylidene-bis- (6-tert-butyl-m-cresol); 4,4′-decylidene-bis- (6-methyl-m-cresol); '-Methylene-bis- (2-amyl-m-cresol); 4,4'-propylidene-bis- (5-hexyl-m-cresol); 3,3'-decylidene-bis- (5-ethyl-p -Cresol); 2,2'-butylidene-bis- (3-n-hexyl-p-cresol); 4,4 '-(2-butylidene) -bis- (6-t-butyl-m-cresol); 3,3'-4 (Deciride ) -Bis- (5-ethyl-p-cresol); (2,5-dimethyl-4-hydroxyphenyl) (2-hydroxy-3,5-dimethylphenyl) methane; (2-methyl-4-hydroxy-5) -Ethylphenyl) (2-ethyl-3-hydroxy-5-methylphenyl) methane; (3-methyl-5-hydroxy-6-t-butylphenyl) (2-hydroxy-4-methyl-5-decylphenyl) (2-hydroxy-4-ethyl-5-methylphenyl) (2-decyl-3-hydroxy-4-methylphenyl) butylamylmethane; (3-ethyl-4-methyl-5-hydroxyphenyl) )-(2,3-dimethyl-3-hydroxy-phenyl) nonylmethane; (3-methyl-2-hydroxy-6-ethylphenyl)-(2-isopropyl Le-3-hydroxy-5-methyl - phenyl) cyclohexyl methane; (2-methyl-4-hydroxy-5-methylphenyl) (2-hydroxy-3-methyl-5-ethylphenyl) dicyclohexylmethane; others.

  Other suitable antioxidants include, but are not limited to, substituted phenols such as 2-tert-butyl-4-methoxyphenol; 3-tert-butyl-4-methoxyphenol; 3-tert-octyl-4- 2-methyl-4-methoxyphenol; 2-stearyl-4-n-butoxyphenol; 3-tert-butyl-4-stearyloxyphenol; 3-lauryl-4-ethoxyphenol; 2,5-di- t-butyl-4-methoxyphenol; 2-methyl-4-methoxyphenol; 2- (1-methylcyclohexyl) -4-methoxyphenol; 2-t-butyl-4-dodecyloxyphenol; 2- (1-methyl Benzyl) -4-methoxyphenol; 2-t-octyl-4-methoxyphenol; methyl gallate; N-butyl gallate; lauryl gallate; myristyl gallate; stearyl gallate; 2,4,5-trihydroxyacetophenol; 2,4,5-trihydroxy-n-butyrophenol; 2,6-ditert-butyl-4-methylphenol; 2,6-ditert-octyl-4-methylphenol; 2,6-ditert-butyl-4-stearylphenol; 2-methyl-4 -Methyl-6-tert-butylphenol; 2,6-distearyl-4-methylphenol; 2,6-dilauryl-4-methylphenol; 2,6-di (n-octyl) -4-methylphenol; 6-di (n-hexadecyl) -4-methylphenol; 2,6-di (1-methylundecyl) 2,6-di (1-methylheptadecyl) -4-methylphenol; 2,6-di (trimethylhexyl) -4-methylphenol; 2,6-di (1,1,3 , 3-tetramethyloctyl) -4-methylphenol; 2-n-dodecyl-6-tertbutyl-4-methylphenol; 2-n-dodecyl-6- (1-methylundecyl) -4-methylphenol; 2 -N-dodecyl-6- (1,1,3,3-tetramethyloctyl) -4-methylphenol; 2-n-dodecyl-6-n-octadecyl-4-methylphenol; 2-n-dodecyl-6 -N-octyl-4-methylphenol; 2-methyl-6-n-octadecyl-4-methylphenol; 2-n-dodecyl-6- (1-methylheptadecyl) -4-methylphenol 2,6-di (1-methylbenzyl) -4-methylphenol; 2,6-di (1-methylcyclohexyl) -4-methylphenol; 2,6- (1-methylcyclohexyl) -4-methyl Phenol; 2- (1-methylbenzyl) -4-methylphenol; and related substituted phenols.

  More suitable antioxidants include, but are not limited to, alkylene bisphenols such as 4,4′-butylidene bis (3-methyl-6-tert-butylphenol); 2,2-butylidene bis (4,6-dimethylphenol). 2,2'-butylidenebis (4-methyl-6-t-butylphenol); 2,2'-butylidenebis (4-t-butyl-6-methylphenol); 2,2'-ethylidenebis (4-methyl-); 6-t-butylphenol); 2,2'-methylidenebis (4,6-dimethylphenol); 2,2'-methylenebis (4-methyl-6-t-butylphenol); 2,2'-methylenebis (4-ethyl) -6-tert-butylphenol); 4,4'-methylenebis (2,6-di-tert-butylphenol); 4,4'-ethylenebis ( -Methyl-6-t-butylphenol); 4,4'-methylenebis (2,6-dimethylphenol); 2,2'-methylenebis (4-t-butyl-6-phenylphenol); 2,2'-dihydroxy 3,3 ′, 5,5′-tetramethylstilbene; 2,2′-isopropylidenebis (4-methyl-6-tert-butylphenol); ethylenebis (beta-naphthol); 1,5-hydroxynaphthalene; 2,4'-ethylenebis (4-methyl-6-propylphenol); 4,4'-methylenebis (2-propyl-6-tert-butylphenol); 4,4'-ethylenebis (2-methyl-6-) Propylphenol); 2,2′-methylenebis (5-methyl-6-tert-butylphenol); and 4,4′-butylidenebis (6-tert-butyl) 3, including the methyl phenol).

  Suitable antioxidants further include, but are not limited to, alkylene triphenols such as 2,6-bis (2′-hydroxy-3′-tert-butyl-5′-methylbenzyl) -4-methylphenol. 2,6-bis (2′-hydroxy-3′-t-ethyl-5′-butylbenzyl) -4-methylphenol; and 2,6-bis (2′-hydroxy-3′-t-butyl-); 5'-mepropylbenzyl) -4-methylphenol.

  Antioxidants are typically present in an amount from about 0.1 phr to about 5 phr, preferably from about 0.1 phr to about 2 phr, more preferably from about 0.1 phr to about 1 phr. In a specific preferred embodiment, the antioxidant is present in an amount of about 0.4 phr.

  In an alternative embodiment, the antioxidant must be present in an amount that ensures that the hardness gradient of the core of the invention is negative. Preferably, the antioxidant is from about 0.2 phr to about 1 phr, more preferably from about 0.3 phr to about 0.8 phr, and most preferably from about 0.4 phr to about 0.7 phr, core layer (inner core or outer Added to the preparation of the core layer). Preferably, from about 0.25 phr to about 1.5 phr peroxide may be added to the core formulation, more preferably from about 0.5 phr to about 1.2 phr, most calculated as 100% activity. Preferably from about 0.7 phr to about 1.0 phr may be added. The amount of ZDA may be varied to suit the desired compression, spinning and feeling of the manufactured bullball. Curing curing involves a temperature range of about 290 ° F. (143 ° C.) to about 335 ° F. (168 ° C.), more preferably about 300 ° F. (149 ° C.) to about 325 ° F. (163 ° C.). The stock is held at that temperature for at least about 10 minutes to about 30 minutes.

  The thermosetting composition of the present invention may contain an optional softening / fastening agent. As used herein, a “soft and fast agent” makes the core 1) softer under a certain COR than when prepared without a softening and speeding agent. (Small compression) or 2) Any compound or blend thereof, or any combination that causes greater compression with equal compression. Preferably, the composition of this invention contains from about 0.05 phr to about 10.0 phr of a softening and speeding agent. In one embodiment, the softening and speeding agent is present in the range of about 0.05 phr to about 3.0 pr, preferably about 0.05 phr to about 2.0 phr, more preferably about 0.05 phr to about 1.0 phr. To do. In other embodiments, the softening and speeding agent ranges from about 2.0 phr to about 5.0 pr, preferably from about 2.35 phr to about 4.0 phr, more preferably from about 2.35 phr to about 3.0 phr. Exists. In an alternative high concentration embodiment, the softening and speeding agent is from about 5.0 phr to about 10.0 pr, more preferably from about 6.0 phr to about 9.0 phr, and most preferably from about 7.0 phr to about 8 phr. It exists in the range of 0.0 phr. In the most preferred embodiment, the softening and speeding agent is present in an amount of about 2.6 phr.

  Suitable softening and speeding agents include, but are not limited to, organic sulfur or metal-containing organic sulfur compounds, inorganic sulfur compounds, Group VIA compounds, or mixtures thereof, where the organic sulfur compounds are mono-, di- And polysulfides, thiols, or mercapto compounds. The softening / accelerator compound may be a blend of an organic sulfur compound and an inorganic sulfur compound.

Suitable softening / acceleration agents of this invention include, but are not limited to, those having the following general formula:

In the formula, R _{1 to} R ₅ may be in any order, and may be a C _{1 to} C ₈ alkyl group; a halogen group; a thiol group (—SH), a carboxylate group; a sulfonate group; and hydrogen. 2-fluorothiophenol; 3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol; 2,4-fluorothiophenol; 3,4-fluorothiophenol; 3,3,4-fluorothiophenol; 3,3,4-fluorothiophenol; 2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetra 4-chlorotetrafluorothiophenol; pentachlorothiophenol; 2-chlorothiopheno 3-chlorothiophenol; 4-chlorothiophenol; 2,3-chlorothiophenol; 2,4-chlorothiophenol; 3,4-chlorothiophenol; 3,5-chlorothiophenol; 4-chlorothiophenol; 3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol; 2,3,5,6-tetrachlorothiophenol; pentabromothiophenol; 2-bromo 3-bromothiophenol; 4-bromothiophenol; 2,3-bromothiophenol; 2,4-bromothiophenol; 3,4-bromothiophenol; 3,5-bromothiophenol; , 4-bromothiophenol; 3,4,5-bromothiophenol; 2,3,4,5-tetrabromothiopheno 2,3,5,6-tetrabromothiophenol; pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol; 4-iodothiophenol; 2,3-iodothiophenol; 3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol; 3,4,5-iodothiophenol; 2,3,4,5-tetraiodo It may be thiophenol; 2,3,5,6-tetraiodothiophenol; and zinc salts thereof. Preferably the halogenated organic sulfur compound is pentachlorothiophenol, which is commercially available in pure form, or added 45 percent of pentachlorothiophenol (equivalent to 2.4 parts of PCTP). It is available under the trade name STRUKTOL®, a clay-based carrier containing sulfur compounds. STRUKTOL ™ is commercially available from StruktolCompanyof America, Stow, Ohio. PCTP is commercially available in pure form from eChinachem, San Francisco, California, and is available in salt form from eChinachem, San Francisco. Most preferably, the halogenated organosulfur compound is a zinc salt of pentachlorothiophenol, which is commercially available from eChinachem, San Francisco.

As used herein in reference to the present invention, the term “organo sulfur compound” refers to any compound containing carbon, hydrogen and sulfur, where the sulfur is directly on at least one carbon. To join. As used herein, the term “sulfur compound” means a compound that is elemental sulfur, polymeric sulfur, or a combination thereof. Further, it should be understood that “elemental sulfur” refers to a ring structure of S ₈ and “polymeric sulfur” is a structure that includes at least one additional sulfur relative to elemental sulfur.

  Additional suitable examples of softening and accelerating agents (which may also be considered cis-trans catalysts) include, but are not limited to, diphenyl disulfide; 4,4′-ditolyl disulfide; 2,2′-benzamide Diphenyl disulfide; bis (2-aminophenyl) disulfide; bis (4-aminophenyl) disulfide; bis (3-aminophenyl) disulfide; 2,2′-bis (4-aminonaphthyl) disulfide; (3-aminonaphthyl) disulfide; 2,2′-bis (4-aminonaphthyl) disulfide; 2,2′-bis (5-aminonaphthyl) disulfide; 2,2′-bis (6-aminonaphthyl) disulfide; 2,2′-bis (7-aminonaphthyl) disulfide; 2,2′-bis (8-aminonaphthyl) disulfide 1,1′-bis (2-aminonaphthyl) disulfide; 1,1′-bis (3-aminonaphthyl) disulfide; 1,1′-bis (3-aminonaphthyl) disulfide; Bis (4-aminonaphthyl) disulfide; 1,1′-bis (5-aminonaphthyl) disulfide; 1,1′-bis (6-aminonaphthyl) disulfide; 1,1′-bis (7-aminonaphthyl) disulfide 1,1′-bis (8-aminonaphthyl) disulfide; 1,2′-diamino-1,2′-dithiodinaphthalene; 2,3′-diamino-1,2′-dithiodinaphthalene; bis (4 -Chlorophenyl) disulfide; bis (2-chlorophenyl) disulfide; bis (3-chlorophenyl) disulfide; bis (4-bromophenyl) disulfide Bis (2-bromophenyl) disulfide; Bis (3-bromophenyl) disulfide; Bis (4-fluorophenyl) disulfide; Bis (4-iodophenyl) disulfide; Bis (2,5-dichlorophenyl) disulfide; Bis (3,5 Bis (2,4-dichlorophenyl) disulfide; bis (2,6-dichlorophenyl) disulfide; bis (2,5-dibromophenyl) disulfide; bis (3,5-dibromophenyl) disulfide; bis (2 -Chloro-5-bromophenyl) disulfide; bis (2,4,6-trichlorophenyl) disulfide; bis (2,3,4,5,6-pentachlorophenyl) disulfide; bis (4-cyanophenyl) disulfide; (2-cyanopheny Bis (4-nitrophenyl) disulfide; bis (2-nitrophenyl) disulfide; 2,2'-dithiobenzoic ethyl; 2,2'-dithiobenzoic methyl; 2,2'-dithiobenzoic acid 4,4'-dithiobenzoic ethyl; bis (4-acetylphenyl) disulfide; bis (2-acetylphenyl) disulfide; bis (4-formylphenyl) disulfide; bis (4-carbamoylphenyl) disulfide; '-Dinaphthyl disulfide; 2,2'-dinaphthyl disulfide; 1,2'-dinaphthyl disulfide; 2,2'-bis (1-chlorodinaphthyl) disulfide; 2,2'-bis (1-bromonaphthyl) ) Disulfide; 1,1′-bis (2-chloronaphthyl) disulfide; 2,2 ′ There is or mixtures thereof; bis (1-cyanonaphthyl) disulfide; 2,2'-bis (1-acetyl-naphthyl) such as disulfide. Preferred organic sulfur compounds are diphenyl disulfide, 4,4'-ditolyl disulfide, or 2,2'-benzamide diphenyl disulfide, or mixtures thereof. A more preferred organic sulfur compound is 4,4'-ditolyl disulfide. In other embodiments, metal-containing organosulfur compounds may be used in accordance with the present invention. Suitable metal-containing organosulfur compounds are, but are not limited to, cadmium, copper, lead, and tellurium analogs of diethyldithiocarbamate, diamyldithiocarbamate, and dimethyldithiocarbamate, or mixtures thereof.

Suitable substituted or unsubstituted aromatic organic components that do not contain sulfur or metals include, but are not limited to, 4,4′-diphenylacetylene, azobenzene, or mixtures thereof. The aromatic organic group is preferably in the range of C _{6 to} C ₂₀ and more preferably in the range of C _{6 to} C _{10 in} size. Suitable inorganic sulfide components include, but are not limited to, titanium sulfide, manganese sulfide, and similar sulfides of iron, calcium, cobalt, molybdenum, tungsten, copper, selenium, yttrium, zinc, tin, and bismuth. Not.

Substituted or unsubstituted aromatic organic compounds are also softening / accelerating agents. Suitable substituted or unsubstituted aromatic organic components include, but are not limited to, components having the formula (R ₁ ) _x —R ₃ —M—R ₄ — (R ₂ ) _y , where R ₁ and R ₂ are each hydrogen, or substituted or unsubstituted C _{1 to} C ₂₀ linear, branched or cyclic alkyl, alkoxy or alkylthio groups, or monocyclic, polycyclic or condensed ring C ₆ to be a C ₂₄ aromatic radical; x and y are each an integer of 0 to 5; _{R 3} and _{R 4} are each a monocyclic, from _C 6 _{-C 24} aromatic group polycyclic or fused Selected; M is an azo group or a metal component. R ₃ and R ₄ are each preferably selected from C ₆ -C ₁₀ aromatic groups, more preferably selected from phenyl, benzyl, naphthyl, benzamide and benzothiazyl. R ₁ and R ₂ are each preferably selected from substituted or unsubstituted C ₁ -C ₁₀ linear, branched or cyclic alkyl, alkoxy or alkylthio groups, or C ₆ -C ₁₀ aromatic groups . If R _{1, R 2,} R ₃ or R ₄ is substituted, the substituent, there may be one or more of the following substituents: hydroxy and metal salts thereof; mercapto and metal salts thereof; halogen; Amino, nitro, cyano and amide; carboxyls including esters, acids and metal salts thereof; silyl; acrylates and metal salts thereof; sulfonyl or sulfonamides; and phosphates and phosphites. When M is a metal component, M can be any suitable elemental metal available to those skilled in the art. Typically, the metal is a transition metal, but is preferably tellurium or selenium. It can be included in the cis-trans-conversion catalyst. In one embodiment, the aromatic organic compound is substantially free of metal, while in other embodiments, the aromatic organic compound is completely free of metal.

  The softening / acceleration agent can also include a Group VIA component. Elemental sulfur and polymeric sulfur are commercially available from, for example, Elastochem, Chardon, Ohio. Examples of sulfur catalyst compounds include PB (RM-S) -80 elemental sulfur and PB (CRST) -65 polymer sulfur, each of which is available from Elastochem. An example of a tellurium catalyst under the trade name “TELLOY” and an example of a selenium catalyst under the trade name “VANDEX” are each commercially available from RT Vanderbilt.

  Other suitable softening and speeding agents include, but are not limited to, hydroquinone, benzoquinone, quinhydrone, catechol, and resorcinol.

The hydroquinone compound is selected from compounds represented by the following chemical formula and hydrates thereof.

Here, each of R ₁ , R ₂ , R ₃ and R ₄ is hydrogen; halogen; alkyl; carboxyl; its metal salt and its ester; acetate and its ester; formyl; acyl; acetyl group; Sulfonyl halide; sulfino; alkyl sulfinyl; carbamoyl; alkyl halide; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl;

  Examples of other suitable hydroquinone compounds include, but are not limited to, hydroquinone; tetrachlorohydroquinone; 2-chlorohydroquinone; 2-bromohydroquinone; 2,5-dichlorohydroquinone; 2,5-dibromohydroquinone; tetrabromohydroquinone; 2-methylhydroquinone; 2-t-butylhydroquinone; 2,5-di-t-amylhydroquinone; and 2- (2-chlorophenyl) hydroquinone hydrate.

More suitable hydroquinone compounds include compounds represented by the following chemical formula and hydrates thereof.

Where R ₁ , R ₂ , R ₃ and R ₄ are each a carboxyl metal salt; acetate and its ester; hydroxy; hydroxy metal salt; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; Or vinyl.

Suitable benzoquinone compounds include compounds represented by the following chemical formula and hydrates thereof.

Here, each of R ₁ , R ₂ , R ₃ and R ₄ is hydrogen; halogen; alkyl; carboxyl; its metal salt and its ester; acetate and its ester; formyl; acyl; acetyl group; Sulfonyl halide; sulfino; alkyl sulfinyl; carbamoyl; alkyl halide; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl;

Other suitable benzoquinone compounds include one or more compounds represented by the following chemical formula and hydrates thereof.

Where R ₁ , R ₂ , R ₃ and R ₄ are each a carboxyl metal salt; acetate and its ester; hydroxy; hydroxy metal salt; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; Or vinyl.

Suitable quinhydrones include one or more compounds represented by the following chemical formula and hydrates thereof.

Where R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each hydrogen; halogen; alkyl; carboxyl; carboxyl metal salt and ester; acetate and ester Acyl; acetyl; carbonyl halide; sulfo and esters thereof; sulfonyl halide; sulfino; alkylsulfinyl; carbamoyl; alkyl halide; cyano; alkoxy; hydroxy and its metal salts; Arylalkyl; nitroso; acetamide; or vinyl.

Other suitable quinhydrones are those having the above formula. _{However, R 1, R 2, R} 3, R 4, R 5, R 6, each of _{R 7} and _{R 8} is a metal salt of a carboxyl; acetate and esters thereof, hydroxy, hydroxy metal salt; amino; nitro; Aryl; aryloxy; arylalkyl; nitroso; acetamide; or vinyl.

Suitable catechols include one or more compounds represented by the following chemical formula and hydrates thereof.

Here, each of R ₁ , R ₂ , R ₃ and R ₄ is hydrogen; halogen; alkyl; carboxyl; its metal salt and its ester; acetate and its ester; formyl; acyl; acetyl group; Sulfonyl halide; sulfino; alkyl sulfinyl; carbamoyl; alkyl halide; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl;

Suitable resorcinols include one or more compounds represented by the following chemical formula and hydrates thereof.

Here, each of R ₁ , R ₂ , R ₃ and R ₄ is hydrogen; halogen; alkyl; carboxyl; its metal salt and its ester; acetate and its ester; formyl; acyl; acetyl group; Sulfonyl halide; sulfino; alkyl sulfinyl; carbamoyl; alkyl halide; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl;

  Fillers may also be added to the core thermosetting composition to adjust the density of the composition upwards or downwards. Fillers are typically tungsten, zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate, metals, metal oxides and salts, liglind (recycled core material, typically about 30 mesh particles ), A high Mooney viscosity rubber liglind, a trans-riglind core material (a recycled core material containing a high trans-isomer of polybutadiene), and the like. When there is trans-ligrind, the amount of trans-isomer is preferably between about 10% and about 60%. In a preferred example of the invention, the core comprises polybutadiene having a cis-isomer content of greater than about 95% and a trans-liglind material (already sulfided) as a filler. A trans-liglind core material of any particle size is sufficient, but is preferably less than about 125 μm.

  Fillers added to one or many parts of a golf ball typically include processing aids or compounds that affect rheological and mixing properties, density adjusting fillers, tear strength or reinforcing fillers, and the like. Fillers are generally inorganic and suitable fillers include a number of metals or metal oxides such as zinc oxide and tin oxide, as well as barium sulfate, zinc sulfate, calcium carbonate, barium carbonate, clay, tungsten, tungsten carbide, silica. Including arrays, and mixtures thereof. Fillers can also include various foaming or blowing agents, which can be easily selected by those skilled in the art. Fillers may include polymers, ceramics, and metals, and the glass microspheres may be solid or hollow and may or may not be filled. Fillers are also typically added to one or more parts of the golf ball to adjust its density and meet uniform golf ball standards. Fillers can also be used to adjust the mass of the at least one additional layer for the center or special ball, for example, a ball with a low mass is preferred for a player with a low swing speed.

  Such as tungsten, zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate, metals, metal oxides and salts, liglind (recycled core material, typically ground to about 30 mesh particles) The material is also a suitable filler.

  Polybutadiene and / or any other base rubber or elastomer system is also foamed or filled with hollow microspheres or expandable microspheres that expand at set temperatures during the curing process to any low specific gravity level. You can. Other ingredients, such as sulfur promoters, specifically tetramethylthiuram, di, tri, or tetrasulfide, and / or metal-containing organic sulfur promoters may be used in accordance with the present invention. Suitable metal-containing organic sulfur promoters include, but are not limited to, cadmium, copper, lead, and ruthenium analogs of diethyldithiocarbamate, diamyldithiocarbamate, and dimethyldithiocarbamate or mixtures thereof. Other ingredients such as processing aids, specifically fatty acids and / or metal salts thereof, processing oils, dyes and pigments, and other additives well known to those skilled in the art A sufficient amount may be used to achieve

  There are three preferred embodiments defined by the present invention, which are preferably golf balls containing a “double core”, where both the inner and outer core layers have a “negative” hardness gradient. Optional zero slope. In the first preferred embodiment, the “low spin” embodiment, the inner surface of the outer core layer is harder than the outer surface of the inner core. In the second preferred embodiment, the “high spin” embodiment, the inner surface of the outer core layer is softer than the outer surface of the inner core. In a third preferred embodiment, the hardness of the inner surface of the outer core layer substantially coincides with the hardness of the outer surface of the inner core and extends continuously from the outer surface of the outer core layer to the center of the inner core. The gradient of is effectively realized.

  In the “low spin” embodiment, the hardness of the inner core (surface, center, or any other point) is 30 Shore C to 80 Shore C, more preferably 40 Shore C to 75 Shore C, most preferably 45 The range is from Shore C to 70 Shore C. At the same time, the hardness of the outer core layer (surface, inner surface, or any other point) is 60 Shore C to 95 Shore C, more preferably 60 Shore C to 90 Shore C, most preferably 65 Shore C to 80 Shore. C range.

  In the “high spin” embodiment, the hardness of the inner core ranges from 60 Shore C to 95 Shore C, more preferably from 60 Shore C to 90 Shore C, and most preferably from 65 Shore C to 80 Shore C. At the same time, the hardness of the outer core layer is in the range of 30 Shore C to 80 Shore C, more preferably 40 Shore C to 75 Shore C, and most preferably 45 Shore C to 70 Shore C.

  In embodiments where the outer core layer and inner core interface (i.e. the region where the two elements meet) have substantially the same hardness, it is realized for either the "low spin" or "high spin" embodiment. The range is also sufficient. However, a “negative” hardness gradient must be maintained and the hardness value of the inner surface of the outer core layer should be approximately the same as the hardness value of the outer surface of the inner core.

  A representative graph showing the hardness region where the “negative” hardness gradient disclosed herein is present is shown in FIGS. Specifically, as in the above-described embodiment, a “negative” slope involves an arbitrary slope (ie, deep slope, shallow slope, or substantially flat). In certain embodiments, the point or points measured along the “negative” gradient may be above or below the line that fits the gradient and the outermost and innermost points. Good. In an alternative preferred embodiment, the hardest point along the specific “negative” slope is greater than the innermost point (geometric center) of the outer core or the innermost point (inner surface) of the outer core layer. Also good. If the outermost point (ie, the outer surface of the inner core) is approximately the same or smaller than the innermost point (ie, the geometric center of the inner core), the “negative” slope is maintained.

  There are a number of suitable and alternative “low spin” embodiments, each of which varies the performance characteristics of the golf ball. In each of the following three examples, the outer diameter of the inner core is preferably about 1.00 inches and the outer diameter of the core (combination of inner core and outer core layer) is preferably about 1.53 inches. . Any of the cover materials listed above are considered suitable and may or may not have an inner cover. Preferably there is an inner cover layer, which consists of an ionomer based material, for example an ionomer neutralized to hardness, preferably the outer cover is made from a urethane or urea material.

a. A golf ball comprising a core made from an inner core and an outer core layer.
The inner core has a center hardness of about 42 Shore C and a surface hardness of about 37 Shore C, realizing the “negative” hardness gradient of the present invention. The hardness of the inner surface of the outer core layer is about 79 Shore C and the hardness of the outer surface is about 73 Shore C, again implementing the “negative” hardness gradient of the present invention. The core has an Atti compression of preferably about 60 and a COR of about 0.790. For the antioxidant (AO), the inner core initiator ratio is about 0.5 and the ZDA level is about 8-10 phr. For the antioxidant, the initiator ratio of the outer core layer is about 0.4 and the ZDA level is about 32-34 hpr. The cure temperature and time for both the inner and outer core layers is about 315 ° F. (157 ° C.) and 11 minutes.

b. A golf ball comprising a core made from an inner core and an outer core layer.
The inner core has a center hardness of about 56 Shore C and a surface hardness of about 55 Shore C, realizing the “negative” hardness gradient of the present invention. The hardness of the inner surface of the outer core layer is about 89 Shore C and the hardness of the outer surface is about 82 Shore C, again realizing the “negative” hardness gradient of the present invention. The core has an Atti compression of preferably about 70 and a COR of about 0.805. For antioxidants, the inner core initiator ratio is about 0.5 and the ZDA level is about 10-12 phr. For the antioxidant, the initiator ratio of the outer core layer is about 0.5 and the ZDA level is about 34-36 hpr. The curing temperature and time for both the inner and outer core layers is about 320 ° F. (160 ° C.) and 11 minutes.

c. A golf ball comprising a core made from an inner core and an outer core layer.
The inner core has a center hardness of about 46 Shore C and a surface hardness of about 44 Shore C, realizing the “negative” hardness gradient of the present invention. The hardness of the inner surface of the outer core layer is about 62 Shore C, and the hardness of the outer surface is about 58 Shore C, again implementing the “negative” hardness gradient of the present invention. The core has an Atti compression of preferably about 65 and a COR of about 0.800. For antioxidants, the inner core initiator ratio is about 0.4 and the ZDA level is about 8-10 phr. For antioxidants, the outer core layer initiator ratio is about 0.3 and the ZDA level is about 26-28 hpr. The cure temperature and time for both the inner and outer core layers is about 315 ° F. (157 ° C.) and 11 minutes.

  There are a number of suitable and alternative “high spin” embodiments, each of which varies a performance characteristic that differs from the performance characteristics of the golf ball achieved by the “low spin” embodiment. As above, in each of the following three examples, the outer diameter of the inner core is preferably about 1.00 inches, and the outer diameter of the core (a combination of inner core and outer core layer) is preferably about 1 .53 inches.

a. A golf ball comprising a core made from an inner core and an outer core layer.
The inner core has a center hardness of about 74 Shore C and a surface hardness of about 71 Shore C, realizing the “negative” hardness gradient of the present invention. The hardness of the inner surface of the outer core layer is about 68 Shore C and the hardness of the outer surface is about 63 Shore C, again realizing the “negative” hardness gradient of the present invention. The core has an Atti compression of preferably about 68 and a COR of about 0.790. For antioxidants, the inner core initiator ratio is about 0.5 and the ZDA level is about 28-30 phr. For antioxidants, the initiator ratio of the outer core layer is about 0.4 and the ZDA level is about 12-14 hpr. The curing temperature and time of the inner core is about 320 ° F. (160 ° C.) and 14 minutes, and the curing temperature and time of the outer core layer is about 320 ° F. (160 ° C.) and 11 minutes.

b. A golf ball comprising a core made from an inner core and an outer core layer.
The inner core has a center hardness of about 86 Shore C and a surface hardness of about 83 Shore C, realizing the “negative” hardness gradient of the present invention. The hardness of the inner surface of the outer core layer is about 61 Shore C, and the hardness of the outer surface is about 57 Shore C, again implementing the “negative” hardness gradient of the present invention. The core's Atti compression is preferably about 74 and the COR is about 0.800. For antioxidants, the inner core initiator ratio is about 0.4 and the ZDA level is about 33-35 phr. For antioxidants, the initiator ratio of the outer core layer is about 0.5 and the ZDA level is about 11-13 hpr. The curing temperature and time of the inner core is about 320 ° F. (160 ° C.) and 14 minutes, and the curing temperature and time of the outer core layer is about 315 ° F. (157 ° C.) and 11 minutes.

c. A golf ball comprising a core made from an inner core and an outer core layer.
The inner core has a center hardness of about 65 Shore C and a surface hardness of about 61 Shore C, realizing the “negative” hardness gradient of the present invention. The hardness of the inner surface of the outer core layer is about 52 Shore C and the hardness of the outer surface is about 49 Shore C, again implementing the “negative” hardness gradient of the present invention. The core has an Atti compression of preferably about 62 and a COR of about 0.785. For antioxidants, the inner core initiator ratio is about 0.5 and the ZDA level is about 22-27 phr. For antioxidants, the outer core layer initiator ratio is about 0.5 and the ZDA level is about 9-11 hpr. The curing temperature and time of the inner core is about 315 ° F. (157 ° C.) and 14 minutes, and the curing temperature and time of the outer core layer is about 315 ° F. (157 ° C.) and 11 minutes.

  An alternative embodiment is that the hardness of the outer surface of the inner core is generally in the range of 42 Shore C to 60 Shore C, and the hardness of the geometric center of the inner core is generally 52 Shore C to 65 Shore C; Golf balls having a “positive hardness gradient” of 0 to −10 are included. In this example, the hardness of the outer surface of the outer core layer is generally in the range of 62 Shore C to 89 Shore C, and the hardness of the inner surface of the outer core layer is generally 58 Shore C to 82 Shore C, The “negative hardness gradient” becomes a magnitude of 10 to 20.

  Furthermore, the hardness of the outer surface of the inner core is in the range of 61 Shore C to 83 Shore C, the hardness of the geometric center of the inner core is 65 Shore C to 86 Shore C, and the “positive hardness gradient” is from 0 It may be -10. In this example, the hardness of the outer surface of the outer core layer is generally in the range of 52 Shore C to 68 Shore C, and the hardness of the inner surface of the outer core layer is generally 49 Shore C to 63 Shore C, The “negative hardness gradient” becomes a magnitude of 10 to 20.

  The above embodiments may be adapted to meet predetermined performance characteristics. For example, alternative embodiments have an outer diameter of about 0.250 inches to about 1.550 inches, preferably about 0.500 inches to about 1.500 inches, more preferably about 0.750 inches to about 1. Includes those with a 400 inch inner core. In preferred embodiments, the outer diameter of the inner core is about 1.000 inches, 1.200 inches, or 1.300 inches, with the most preferred outer diameter being 1.130 inches. The outer diameter of the outer core layer (total dual core) is from about 1.30 inches to about 1.620 inches, preferably from about 1.400 inches to about 1.600 inches, more preferably from about 1.500 inches to about 1.590 inches. In the preferred embodiment, the outer diameter of the outer core layer is about 1.510 inches, 1.530 inches, and most preferably 1.550 inches.

（＊）ＶＡＮＯＸ ＭＢＰＣ：Ｒ．Ｔ．Ｖａｎｄｅｒｂｉｌｔから入手可能な２，２’−メチレン−ビス−（４−メチル−６−ｔ−ブチルフェノール）
（＊＊）ＴＲＩＧＯＮＯＸ ２６５−５０Ｂ：Ａｋｚｏ Ｎｏｂｅｌから入手可能な非活性キャリア上で５０％活性な１，１−ジ（ｔ−ブチルペルオキシ）−３，３，５−トリメチルシクロヘキサンおよびジ（２−ｔ−ブチルペルオキシイソプロピル）ベンゼンの混合物
（＊＊＊）Ｐｅｒｋａｄｏｘ ＢＣ−ＦＦ：Ａｋｚｏ Ｎｏｂｅｌから入手可能なジクミルペルオキシド（９９％−１００％活性）
（＋）ＳＲ−５２６：Ｓａｒｔｏｍｅｒから入手可能なＺＤＡ

A number of cores were produced based on the formulation and cure cycle described in Table 1 below, and their core hardness values are reported in Table 2 below and plotted in FIG.

(*) VANOX MBPC: R. T.A. 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol) available from Vanderbilt
(**) TRIGONOX 265-50B: 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane and di (2-t 50% active on non-active carrier available from Akzo Nobel -Butylperoxyisopropyl) benzene mixture (***) Perkadox BC-FF: Dicumyl peroxide available from Akzo Nobel (99% -100% active)
(+) SR-526: ZDA available from Sartomer

  The surface hardness of the core is obtained from the average of a number of measurements taken from the opposing hemisphere of the core and care is taken not to make measurements on the core separation lines or surface defects, such as holes or protrusions. The hardness is measured according to ASTM D-2240 “Durometer rubber and plastic dent hardness”. Since the core is a curved surface, it must be handled so that the core can be centered directly under the durometer indenter before the surface hardness can be read. One calibrated digital durometer capable of reading up to 0.1 units was used for all hardness measurements and was set to take a hardness reading 1 second after the maximum reading was obtained. The digital durometer must be mounted on the base of the auto stand with its legs parallel so that the weight and attack speed on the durometer conforms to ASTM D-2240.

  To prepare for the hardness gradient measurement of the core, the core is gently pushed into a hemispherical holder whose inner diameter is slightly smaller than the core diameter, and the core is held stationary in the hemispherical part of the holder, while at the same time the geometric center plane of the core To be exposed. The core is fixed in the holder by friction to prevent movement during the cutting and polishing steps. However, friction should not be excessive and the natural shape of the core should not be deformed. The core is fixed so that the separation line of the core is approximately parallel to the top of the holder. Before fixing the core, the core diameter is measured at 90 ° to this configuration. In addition, the distance from the bottom of the holder to the top of the core is measured to obtain a reference point for future calibration. Roughly cut using a band saw or other suitable cutting tool, just above the exposed geometric center of the core, keeping the core from moving within the holder during this step. The remaining part of the core still held in the holder is secured to the base plate of the surface polisher. The exposed “rough” core surface is polished to a smooth, flat surface to reveal the core's geometric center, which can be verified by measuring the height from the bottom of the holder to the exposed surface of the core . This ensures that exactly half of the original height of the core has been removed within the range of + -0.004 inches.

  Hold the core in the holder, find the center of the core with a centering ruler, mark it carefully, and measure the hardness with this center mark. Hardness measurements at an arbitrary distance from the center of the core are made by drawing a line extending radially outward from the center and measuring and marking the distance from the center, typically in 2 mm increments. Even if all hardness measurements are performed on a plane that passes through the geometric center, the core is still in the holder so that its configuration is not disturbed and the measurement plane is always parallel to the bottom of the holder . The hardness difference from any predetermined point on the core is calculated by subtracting the appropriate reference point from the average surface hardness, e.g. for a single solid core, the hardness at the center of the core, and the core surface softer than the center will be negative. The hardness gradient is as follows.

  Referring to Tables 1 and 2, in Example 1, the surface is 10 Shore C smaller than the center hardness and 12 Shore C smaller than the point of greatest hardness in the core. In Example 3, the surface is 5 Shore C less than the center hardness and 8 Shore C less than the point of greatest hardness in the core. In Example 2, the center and surface hardness values are equal and the softest point in the core is 10 Shore C smaller than the surface.

  In the example of the invention presented in Table 1, the curing temperature varies from 305 ° F. (152 ° C.) to 320 ° F. (160 ° C.) and the curing time varies from 11 to 16 minutes. The core composition of Examples 1 and 2 is vaginal and only the cure cycle is changed. In Example 3, the amount of antioxidant is the same as in Examples 1 and 2, but the other ingredients and the cure cycle are changed. Furthermore, the ratio of antioxidant to initiator varies from 0.50 to 0.57 in Examples 1, 2 and 3.

  The ratio of antioxidant to initiator is one factor that controls the surface hardness of the core. From the data shown in Table 2, it can be seen that the hardness gradient depends on, but is not limited to, the amount of antioxidants and peroxides, their ratio, and the cure cycle. Note that the more antioxidants, the more peroxide initiators are required to achieve the desired compression.

  In FIG. 1, the cores of Comparative Examples 1 to 3 are compared with the core of the present invention. The composition of the core of Comparative Example 1 is shown in Table 1 and was cured using a normal core cycle with a cure temperature of 350 ° F. (177 ° C.) and a cure time of 11 minutes. The core of this invention was manufactured using a cure cycle of 305 ° F. (152 ° C.), 14 minutes, 315 ° F. (157 ° C.), 11 minutes. The hardness gradient of these cores is measured and the following observations can be made. For the core of the comparative example, as expected, a normal gradient from a hard surface to a soft center can be clearly found. The gradients of the cores of the present invention take substantially the same shape as each other.

  In a preferred embodiment of the invention, the hardness of the core at the surface is at most about the same as or less than the hardness of the core at the center. Furthermore, the central hardness of the core may not be the hardest point in the core, but in all cases it is preferred that it be at least as hard as the surface. Furthermore, there is no need for the surface to have the least hardness anywhere in the core. In some embodiments, the smallest hardness value is within 6 mm outward of the core surface. However, as long as the surface hardness is still equal to or smaller than the center hardness, the smallest hardness value in the core may be at the surface or any point from the surface except the center. It should be noted that in the present invention, the preparation is the same throughout the core or core layer, and no surface treatment is applied to obtain a desirable surface hardness.

Although the golf balls of the present invention may be made from a variety of different conventional cover materials (both intermediate and outer cover layers), preferred cover materials include, but are not limited to:
(1) Polyurethanes, such as those prepared from polyols or polyamines and diisocyanates or polyisocyanates and / or prepolymers thereof, as well as in US Pat. Nos. 5,33,4673 and 6,506,851 What is disclosed.
(2) Polyureas such as those disclosed in US Pat. Nos. 5,484,870 and 6,835,794.
(3) A polyurethane-urea hybrid, blend or copolymer comprising urethane or urea segments.
Suitable polyurethane compositions include the reaction product of at least one polyisocyanate and at least one curing agent. The curing agent may include, for example, one or more polyamines, one or more polyols, or combinations thereof. The polyisocyanate may be combined with one or more polyols to form a prepolymer. This is combined with at least one curing agent as described above. Thus, the polyols described herein are suitable as one or both elements of the polyurethane material. That is, it is suitable for use as a part of the prepolymer and the curing agent. Suitable polyurethanes are described in US Patent Application Publication No. 2005/0176526, the contents of which are hereby incorporated by reference.

Any polyisocyanate available to those skilled in the art is suitable for use in accordance with the present invention. Examples of polyisocyanates include, but are not limited to: 4,4′-diphenylmethane diisocyanate (“MDI”); polymer MDI; carbodiimide-modified liquid MDI; 4,4′-dicyclohexylmethane diisocyanate (“H ₁₂ MDI”) P-phenylene diisocyanate (“PPDI”); m-phenylene diisocyanate (“MPDI”); toluene diisocyanate (“TDI”); 3,3′-dimethyl-4,4′-biphenylene diisocyanate (“TODI”); Isophorone diisocyanate ("IPDI"); hexamethylene diisocyanate ("HDI"); naphthalene diisocyanate ("NDI"); xylene diisocyanate ("XDI"); p-tetramethylxylene diisocyanate ("p-TM") DI "); m-tetramethylxylene diisocyanate (" m-TMXDI "); ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,4-diisocyanate; cyclohexyl diisocyanate; 1,6-hexamethylene-diisocyanate ( "HDI");dodecane-1,12-diisocyanate;cyclobutane-1,3-diisocyanate;cyclohexane-1,3-diisocyanate;cyclohexane-1,4-diisocyanate; 1-isocyanate-3,3,5-trimethyl-5 -Isocyanate methylcyclohexane; methylcyclohexylene diisocyanate; triisocyanate of HDI; triisocyanate of 2,4,4-trimethyl-1,6-hexane diisocyanate ("T DI "); tetracene diisocyanate; naphthalene diisocyanate; anthracene diisocyanate; and mixtures thereof; uretdione of hexamethylene diisocyanate; the isocyanurate of toluene diisocyanate. Polyisocyanates are known to those skilled in the art as having one or more isocyanate groups such as diisocyanates, triisocyanates and tetraisocyanates. Preferably, the polyisocyanate comprises MDI, PPDI, TDI, or mixtures thereof, more preferably the polyisocyanate comprises MDI. As used herein, the term “MDI” means 4,4′-diphenylmethane diisocyanate, polymeric MDI, carbodiimide-modified liquid MDI, and mixtures thereof, and the diisocyanate used is also “low free monomer”. It should be understood by those skilled in the art that the amount of “free” monomer is a low isocyanate group, typically that the amount of free monomer group is less than about 0.1%. is there. Examples of “low free monomer” diisocyanates include, but are not limited to, low free monomer MDI, low free monomer TDI, and low free monomer PPDI.

  The at least one polyisocyanate should have less than about 14% unreacted NCO groups. Preferably the at least one polyisocyanate has no more than about 7.5% NCO, more preferably less than about 7.0%.

  Any polyol available to one skilled in the art is suitable for use in accordance with the present invention. Examples of polyols include, but are not limited to, polyether polyols, hydroxy-terminated polybutadienes (including partially / fully hydrogenated derivatives), polyester polyols, polycaprolactone polyols, and polycarbonate polyols. In a preferred embodiment, the polyol comprises a polyether polyol. Examples are, but not limited to, polytetramethylene ether glycol (“PTMEG”), polyethylene propylene glycol, polyoxypropylene glycol, and mixtures thereof. The hydrocarbon chain can have saturated or unsaturated bonds and substituted or unsubstituted aromatic and cyclic groups. Preferably, the polyol of this invention comprises PTMEG.

  In another embodiment, the polyurethane material of this invention includes a polyester polyol. Suitable polyester polyols include, but are not limited to, polyethylene adipate glycol; polybutylene adipate glycol; polyethylene propylene adipate glycol; o-phthalate-1,6-hexanediol; poly (hexamethylene adipate) glycol; and mixtures thereof It is. The hydrocarbon chain can have saturated or unsaturated bonds, or substituted or unsubstituted aromatic and cyclic groups.

  In another embodiment, the polyurethane material of this invention includes a polycaprolactone polyol. Suitable polycaprolactone polyols include, but are not limited to, 1,6-hexanediol-initiated polycaprolactone, diethylene glycol initiated polycaprolactone, trimethylolpropane initiated polycaprolactone, neopentyl glycol initiated polycaprolactone, 1,4-butanediol initiated Polycaprolactone, PTMEG-initiated polycaprolactone, and mixtures thereof. The hydrocarbon chain can have saturated or unsaturated, or substituted or unsubstituted aromatic and cyclic groups.

  In yet another embodiment, the polyurethane material of this invention includes a polycarbonate polyol. Suitable polycarbonates include, but are not limited to, polyphthalate carbonate and poly (hexamethylene carbonate) glycol. The hydrocarbon chain can have saturated or unsaturated bonds, or substituted or unsubstituted aromatic and cyclic groups. In one example, the molecular weight of the polyol is from about 200 to about 4000.

  Polyamine curing agents are also suitable for use in the polyurethane compositions of this invention and have been found to improve the cut resistance, shear resistance, and impact resistance of product balls. Preferred polyamine curing agents include, but are not limited to, 3,5-dimethylthio-2,4-toluenediamine and its isomer; 3,5-diethyltoluene-2,4-diamine and its isomer, such as 3,5-diethyl Toluene-2,6-diamine; 4,4′-bis- (sec-butylamino) -diphenylmethane; 1,4-bis- (sec-butylamino) -benzene, 4,4′-methylene-bis- (2 -Chloroaniline); 4,4'-methylene-bis- (3-chloro-2,6-diethylaniline) ("MCDEA"); polytetramethylene oxide-di-p-aminobenzoate; N, N'-dialkyl Diaminodiphenylmethane; p, p'-methylenedianiline ("MDA"); m-phenylenediamine ("MPDA"); -Methylene-bis- (2-chloroaniline) ("MOCA"); 4,4'-methylene-bis- (2,6-diethylaniline) ("MDEA"); 4,4'-methylene-bis- ( 2,3-dichloroaniline) (“MDCA”); 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphenylmethane; 2,2′-3,3′-tetrachlorodiaminodiphenylmethane; Trimethylene glycol di-p-aminobenzoate; and mixtures thereof. Preferably, the curing agent of the present invention is 3,5-dimethylthio-2,4-toluenediamine and its isomers, such as Ethacure® available from Albemarle Corporation of Baton Rouge, LA. 300. Suitable polyamine curing agents include both primary and secondary amines, and preferably have a molecular weight in the range of about 64 to about 2000.

  At least one diol, triol, tetraol, or hydroxy-terminated curing agent can be added to the polyurethane composition described above. Suitable diol, triol, and tetraol groups include: ethylene glycol; diethylene glycol; polyethylene glycol; propylene glycol; polypropylene glycol; low molecular weight polytetramethylene ether glycol; 1,3-bis- [2- (2-hydroxyethoxy) ethoxy] benzene; 1,3-bis- {2- [2- (2-hydroxyethoxy) ethoxy] ethoxy} benzene; 1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol; resorcinol-di- (β-hydroxyethyl) ether; hydroquinone-di- (β-hydroxyethyl) ether; and mixtures thereof. Preferred hydroxy-terminated curing agents are 1,3-bis (2-hydroxyethoxy) benzene; 1,3-bis- [2- (2-hydroxyethoxy) ethoxy] benzene; 1,3-bis- {2- [2 -(2-hydroxyethoxy) ethoxy] ethoxy} benzene; 1,4-butanediol, and mixtures thereof. Preferably, the molecular weight of the hydroxy-terminated curing agent ranges from about 48 to about 2000. Here, the molecular weight is the absolute weight average Bunshiro, as understood by those skilled in the art.

  Both the hydroxy terminus and the amine curing agent can contain one or more saturated, unsaturated, aromatic, and cyclic groups. In addition, the hydroxy terminus and the amine curing agent can include one or more halogen groups. Polyurethane compositions can be made by blends or mixtures of curing agents. However, if desired, the polyurethane composition can be made with a single curing agent.

  In a preferred embodiment of the present invention, the saturated polyurethane used to form the cover layer, particularly the outer cover layer, can be selected from both castable thermoset and thermoplastic polyurethane.

  In this example, the saturated polyurethane of this invention is substantially free of aromatic groups or moieties. Saturated polyurethanes suitable for use in this invention are the reaction products of at least one polyurethane prepolymer and at least one saturated curing agent. The polyurethane prepolymer is a reaction product of at least one polyol and at least one saturated diisocyanate. As is well known in the art, a catalyst may be employed to promote the reaction of the curing agent and the isocyanate and polyol.

  Saturated diisocyanates that can be used include, but are not limited to, ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexamethylene diisocyanate ("HDI"); 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; dicyclohexylmethane diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1 , 4-diisocyanate; 1-isocyanate-3,3,5-trimethyl-5-isocyanate methylcyclohexane; isophorone diisocyanate; methylcyclohexylene dii Cyanate; HDI triisocyanate, including triisocyanate 2,2,4-trimethyl-1,6-hexane diisocyanate. The most preferred saturated diisocyanates are 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate.

  Saturated polyols suitable for use in this invention are, but not limited to, polyether polyols such as polytetramethylene ether glycol and poly (oxypropylene) glycol. Suitable saturated polyester polyols are polyethylene adipate glycol, polyethylene propylene adipate glycol, polybutylene adipate glycol, polycarbonate polyol and ethylene oxide capped polyoxypropylene diol. Saturated polycaprolactone polyols useful in this invention include diethylene glycol initiated polycaprolactone, 1,4-butanediol initiated polycaprolactone, 1,6-hexanediol initiated polycaprolactone; trimethylolpropane initiated polycaprolactone, neopentyl glycol initiated polycaprolactone, And polytetremethyl ether glycol initiated polycaprolactone. The most preferred saturated polyols are PTMEG and PTMEG initiated polycaprolactone.

  Suitable saturated hardeners are 1,4-butanediol, ethylene glycol, diethylene glycol, polytetramethylene ether glycol, propylene glycol; trimethanol propane; tetra- (2-hydroxypropyl) -ethylenediamine; isomers of cyclohexyldimethylol isomers. And mixtures, isomers and mixtures of isomers of cyclohexanebis (methylamine); triisopropanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, 4,4'-dicyclohexylmethanediamine, 2,2,4-trimethyl- 1,6-hexanediamine; 2,4,4-trimethyl-1,6-hexanediamine; diethylene glycol di- (aminopropyl) ether 4,4′-bis- (sec-butylamino) -dicyclohexylmethane; 1,2-bis- (sec-butylamino) cyclohexane; 1,4-bis- (sec-butylamino) cyclohexane; isophoronediamine, hexamethylene Diamine, propylenediamine, 1-methyl-2,4-cyclohexyldiamine, 1-methyl-2,6-cyclohexyldiamine, 1,3-diaminopropane, dimethylaminopropylamine, diethylaminopropylamine, imido-bis-propylamine, Isomers and mixtures of diaminocyclohexane isomers, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, and diisopropanolamine. The most preferred saturated curing agents are 1,4-butanediol, 1,4-cyclohexyldimethylol and 4,4'-bis- (sec-butylamino) -dicyclohexylmethane.

  Alternatively, other suitable polymers include partially or fully neutralized ionomers, metallocenes, or other single site catalyst polymers, polyesters, polyamides, non-ionomer thermoplastic elastomers, copolyether-esters, Copolyether-amides, polycarbonates, polybutadienes, polyisoprenes, polystyrene block copolymers (eg, styrene-butadiene-styrene), styrene-ethylene-propylene-styrene, styrene-ethylene-butylene-styrene, and the like, and blends thereof. Thermosetting polyurethane or polyurea is suitable as the outer cover layer of the golf ball of the present invention.

  Further, the polyurethane may be replaced with a polyurea material or blended. Polyureas are clearly different from polyurethane compositions, but provide the desired aerodynamic and aesthetic properties when used in golf ball components. The polyurea-based composition is preferably saturated in nature.

  Without being bound by any particular theory, by replacing the long-chain polyol segment in the polyurethane prepolymer with a long-chain polyetherdiamine oligomer soft segment to form a polyurea prepolymer, shear, cutability and It is currently believed that the impact resilience is improved and the adhesion to other components is improved. Accordingly, the polyurea composition of the present invention comprises a reaction product of an isocyanate and a polyamine prepolymer crosslinked with a curing agent. For example, the polyurea-based composition of this invention may be prepared from at least one isocyanate, at least one polyetheramine, and at least one diol curing agent or at least one diamine curing agent.

  All polyamines available to those skilled in the art are suitable for use in the polyurea prepolymer. Polyether amines are particularly suitable in the prepolymer. As used herein, the term “polyetheramine” means at least a polyoxyalkyleneamine comprising a primary amino group bonded to the end of the polyether backbone. However, the choice of diamines and polyetheramines is limited to those that allow the formation of polyurea prepolymers because of the rapid reaction of isocyanate and amine and the insolubility of many urea products. In one example, the polyether backbone is based on tetramethylene, propylene, ethylene, trimethylolpropane, glycerin, and mixtures thereof.

  Suitable polyether amines include, but are not limited to, polytetramethylene ether diamine, polyoxypropylene diamine, poly (ethylene oxide terminated oxypropylene) ether diamine, triethylene glycol diamine, propylene oxide based triamine, trimethylolpropane. Based triamines, glycerin based triamines, and mixtures thereof. In one example, the polyetheramine used to make the prepolymer is JEFFAMINE ™ D2000 (Huntsman, Austin, Texas).

  The molecular weight of the polyetheramine used in the polyurea prepolymer is in the range of about 100 to about 5000. In one example, the molecular weight of the polyetheramine is about 230 or greater. In other examples, the molecular weight of the polyetheramine is about 4000 or less. In yet another embodiment, the molecular weight of the polyetheramine is about 600 or greater. In yet another embodiment, the molecular weight of the polyetheramine is about 3000 or less. In yet another embodiment, the molecular weight of the polyetheramine is from about 1000 to about 3000, more preferably from about 1500 to about 2500. A low molecular weight polyetheramine tends to form solid polyurea, so a high molecular weight oligomer such as JEFFAMINE D2000 is preferred.

  As mentioned briefly above, many amines are unsuitable for reaction with isocyanates due to the rapid reaction of amines with isocyanates. In particular, short-chain amines react quickly. However, in one example, a sterically hindered second diamine may be suitable for use in a prepolymer. Without being bound by any particular theory, amines with a high degree of steric hindrance, such as amines with a tertiary butyl group attached to the nitrogen atom, are more kinetic than amines with no or less hindrance. Is thought to be slow. For example, 4,4'-bis- (sec-butylamino) -dicyclohexylmethane (CLEARLINK ™ 1000) may be suitable for producing a polyurea prepolymer in combination with an isocyanate.

  Any isocyanate available to those skilled in the art is suitable for use in the polyurea prepolymer. The isocyanates used in the present invention include aliphatic, cycloaliphatic, araliphatic, aromatic, any of these derivatives, and combinations of these compounds having two or more isocyanate (NCO) groups per molecule. Including. Isocyanates can be organic polyisocyanate-terminated prepolymers, lower free isocyanates, and mixtures thereof. The reactive component comprising an isocyanate can include any isocyanate functional monomer, dimer, trimer, or multimeric adducts, prepolymers, pseudoprepolymers, or mixtures thereof. Isocyanate functional compounds can include monoisocyanates or polyisocyanates containing two or more isocyanate functional groups.

  Suitable isocyanate-containing components include diisocyanates having the following general formula: O═C═N—R—N═C═O, wherein R is preferably cyclic, aromatic containing from about 1 to about 20 carbon atoms. Or a straight or branched hydrocarbon moiety. The diisocyanate may further comprise one or more cyclic groups or one or more phenyl groups. When a polycyclic group or aromatic group is present, linear and / or branched hydrocarbons containing from about 1 to about 10 carbon atoms can be present as a spacer between the cyclic group or aromatic group. . In some cases, the cyclic or aromatic group may be substituted in the 2-, 3-, and / or 4-position, or in the ortho-, meta- and / or para-position, respectively. The substituted group is, but not limited to, a halogen, a first, second, or third hydrocarbon group, or a mixture thereof.

  Examples of diisocyanates that can be used in the present invention include, but are not limited to, substituted and isomeric mixtures including 2,2'-, 2,4'-, and 4,4'-diphenylmethane diisocyanate; 3'-dimethyl-4,4'-biphenylene diisocyanate; toluene diisocyanate; polymer MDI; carbodiimide-modified liquid 4,4'-diphenylmethane diisocyanate; para-phenylene diisocyanate; meta-phenylene diisocyanate; triphenylmethane-4,4'- And triphenylmethane-4,4 "-triisocyanate; naphthylene-1,5-diisocyanate; 2,4'-, 4,4'- and 2,2-biphenyl diisocyanate; polyphenylpolymethylene polyisocyanate; and MDI PMDI blend A mixture of PMDI and TDI; ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,2-diisocyanate; tetramethylene-1,3-diisocyanate; tetramethylene-1,4-diisocyanate; Octamethylene diisocyanate; octamethylene diisocyanate; decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; dicyclohexylmethane diisocyanate; cyclobutane-1, 3-diisocyanate; cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate Methyl 4-cyclohexylene diisocyanate; 2,6-methylcyclohexane diisocyanate; 4,4'-dicyclohexyl diisocyanate; 2,4'-dicyclohexyl diisocyanate; 1,3,5-cyclohexane triisocyanate; Isocyanate methylcyclohexane isocyanate; 1-isocyanate-3,3,5-trimethyl-5-isocyanate methylcyclohexane; isocyanate ethylcyclohexane isocyanate; bis (isocyanatemethyl) -cyclohexane diisocyanate; 4,4′-bis (isocyanatemethyl) dicyclohexane; 2,4'-bis (isocyanatomethyl) dicyclohexane; isophorone diisocyanate; HD Triisocyanate of I; Triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate; 4,4′-dicyclohexylmethane diisocyanate; 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; 1,2-, 1,3- and 1,4-phenylene diisocyanates; aromatic aliphatic isocyanates such as 1,2-, 1,3- and 1,4-xylene diisocyanates; meta-tetramethylxylene diisocyanates; Para-tetramethylxylene diisocyanate; trimerized isocyanurate of any polyisocyanate, such as isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, tetramethylxylene diisocyanate Trimer, hexamethylene diisocyanate isocyanurate, and mixtures thereof; dimerized ureizions of any polyisocyanate, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and mixtures thereof; Modified polyisocyanates derived from polyisocyanates; and mixtures thereof.

  Examples of saturated diisocyanates that can be used in this invention include, but are not limited to, ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexa Octamethylene diisocyanate; decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; dicyclohexylmethane diisocyanate; cyclobutane-1,3 -Diisocyanate; Cyclohexane-1,2-diisocyanate; Cyclohexane-1,3-diisocyanate; Cyclohexane-1,4-diisocyanate 2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate; 4,4'-dicyclohexyl diisocyanate; 2,4'-dicyclohexyl diisocyanate; 1,3,5-cyclohexane triisocyanate Isocyanate methylcyclohexane isocyanate; 1-isocyanate-3,3,5-trimethyl-5-isocyanate methylcyclohexane; isocyanate ethylcyclohexane isocyanate; bis (isocyanate methyl) -cyclohexane diisocyanate; 4,4′-bis (isocyanate methyl) dicyclohexane 2,4′-bis (isocyanatomethyl) dicyclohexane; isophorone diisocyanate; HD 2,4,4-trimethyl-1,6-hexane diisocyanate; 4,4'-dicyclohexylmethane diisocyanate; 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; Including these mixtures. Aromatic aliphatic isocyanates can also be used to produce light stable materials. Examples of these isocyanates include: 1,2-, 1,3- and 1,4-xylene diisocyanates; meta-tetramethylxylene diisocyanate (m-TMXDI); para-tetramethylxylene diisocyanate (p-TMXDI) ); Trimerized isocyanurates of any polyisocyanate, such as isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate of hexamethylene diisocyanate, and mixtures thereof; A dimerized ureasione of any of the polyisocyanates, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and mixtures thereof; It is and mixtures thereof; where over preparative and polyisocyanates modified derived from a polyisocyanate. Furthermore, aromatic aliphatic isocyanates can be mixed with any of the saturated isocyanates listed above for the purposes of the present invention.

  By changing the number of unreacted NCO groups in the polyurea prepolymer of isocyanate and polyetheramine, factors such as reaction rate and hardness of the resulting composition can be controlled. For example, the number of unreacted NCO groups in the polyurea prepolymer of isocyanate and polyetheramine can be less than about 14%. In one example, the polyurea prepolymer has from about 5% to about 11% unreacted NCO groups, more preferably from about 6% to about 9.5% unreacted NCO groups. In one example, the proportion of unreacted NCO groups is about 3% to about 9%. Alternatively, the proportion of unreacted NCO groups is about 7.5% or lower, more preferably about 7% or lower. In other examples, the proportion of unreacted NCO groups is from about 2.5% to about 7.5%, more preferably from about 4% to about 6.5%.

  As produced, the polyurea prepolymer may comprise from about 10% to about 20% by weight of the free isocyanate monomer of the prepolymer. As a result, in one embodiment, free isocyanate monomer may be removed from the polyurea prepolymer. For example, after removal, the prepolymer will contain 1% or less of free isocyanate monomer. In other examples, the prepolymer may comprise about 0.5% by weight or less than free isocyanate monomer.

  Polyetheramine can be blended with additional polyol to form a copolymer that can be reacted with excess isocyanate to produce a polyurea prepolymer. In one embodiment, less than about 30% by weight of the copolymer is blended with a saturated polyetheramine. In other examples, less than about 20% by weight of the copolymer, preferably less than about 15% by weight of the copolymer is blended with the saturated polyetheramine. Any saturated polyol available to those skilled in the art, such as polyether polyols, polycaprolactone polyols, polyester polyols, polycarbonate polyols, hydrocarbon polyols, other polyols, and mixtures thereof are suitable for blending in accordance with the present invention. Yes. The molecular weight of these polymers can be from about 200 to about 4000, but can be from about 1000 to about 3000, more preferably from about 1500 to about 2500.

  Polyurea compositions can be made by cross-linking a polyurea prepolymer with a single curing agent or blend thereof. The curing agent used in this invention is preferably an amine-terminated curing agent, more preferably a second diamine curing agent, so that the composition contains only a single urea bond. In one example, the molecular weight of the amine-terminated curing agent is about 64 or greater. In other examples, the molecular weight of the amine-terminated curing agent is about 2000 or less. As noted above, certain amine-terminated curing agents may be modified with compatible amine-terminated freezing point depressants or mixtures thereof.

  Suitable amine-terminated curing agents include, but are not limited to, ethylenediamine; hexamethylenediamine; 1-methyl-2,6-cyclohexyldiamine; tetrahydroxypropyleneethylenediamine; 2,2,4- and 2,4,4- Trimethyl-1,6-hexanediamine; 4,4′-bis- (sec-butylamino) -dicyclohexylmethane; 1,4-bis- (sec-butylamino) -cyclohexane; 1,2-bis- (sec- Butylamino) -cyclohexane; 4,4′-bis- (sec-butylamino) -dicyclohexylmethane derivative; 4,4′-dicyclohexylmethanediamine; 1,4-cyclohexane-bis- (methylamine); -Cyclohexane-bis- (methylamine); diethylene glycol di- (amino 2-methylpentamethylene-diamine; diaminocyclohexane; diethylenetriamine; triethylenetetramine; tetraethylenepentamine; propylenediamine; 1,3-diaminopropane; dimethylaminopropylamine; diethylaminopropylamine; imido-bis-propyl Amine; monoethanolamine, diethanolamine; triethanolamine; monoisopropanolamine, diisopropanolamine; isophoronediamine; 4,4′-methylenebis- (2-chloroaniline); 3,5-dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; 3,5-diethylthio-2,4-toluenediamine; 3,5-diethylthio-2,6-toluenediamine 4,4′-bis- (sec-butylamino) -diphenylmethane and its derivatives; 1,4-bis- (sec-butylamino) -benzene; 1,2-bis- (sec-butylamino) -benzene; N , N′-dialkylamino-diphenylmethane; trimethylene glycol-di-aminobenzoate; polytetramethylene oxide-di-p-aminobenzoate; 4,4′-methylenebis- (3-chloro-2,6-diethyleneaniline); 4,4'-methylenebis- (2,6-diethylaniline); meta-phenylenediamine; para-phenylenediamine; cyclohexyldimethol; and mixtures thereof. In one example, the amine-terminated curing agent is 4,4'-bis- (sec-butylamino) -dicyclohexylmethane.

  Suitable saturated amine-terminated curing agents include, but are not limited to, ethylenediamine; hexamethylenediamine; 1-methyl-2,6-cyclohexyldiamine; tetrahydroxypropyleneethylenediamine; 2,2,4- and 2,4,4. -Trimethyl-1,6-hexanediamine; 4,4'-bis- (sec-butylamino) -dicyclohexylmethane; 1,4-bis- (sec-butylamino) -cyclohexane; 1,2-bis- (sec -Butylamino) -cyclohexane; 4,4'-bis- (sec-butylamino) -dicyclohexylmethane derivative; 4,4'-dicyclohexylmethanediamine; 1,4-cyclohexane-bis- (methylamine); 3-cyclohexane-bis- (methylamine); diethylene glycol di- ( 2-methylpentamethylene-diamine; diaminocyclohexane; diethylenetriamine; triethylenetetramine; tetraethylenepentamine; propylenediamine; 1,3-diaminopropane; dimethylaminopropylamine; diethylaminopropylamine; Amines; monoethanolamines, diethanolamines; triethanolamines; monoisopropanolamines, diisopropanolamines; isophoronediamines; triisopropanolamines; and mixtures thereof. In addition, any of the above polyether amines can be used as a curing agent to react with the polyurea prepolymer.

  The center and optional layers of a golf ball can be made from a highly neutralized polymer (“HNP”). The acid portion of HNP is typically an ethylene-based ionomer, preferably more than about 70%, more preferably more than about 90%, and most preferably at least about 100% neutralized. HNP can also be blended with the second polymer component, and if this component contains acid groups, it can be neutralized according to conventional methods, with organic fatty acids of the present invention, or both. . The second polymer component may be partially or fully neutralized, preferably ionomer copolymers and ionomer terpolymers, ionomer precursors, thermoplastics, polyamides, polycarbonates, polyesters, polyurethanes, polyureas, heat Includes plastic elastomers, polybutadiene rubber, balata, metallocene catalyzed polymers (grafted and ungrafted), single site polymers, highly crystalline acid polymers, cationic ionomers, and the like. The material hardness of the HNP polymer is typically between about 20 and about 80 Shore D, and the flexural modulus is between about 3,000 psi and about 200,000.

In one embodiment of the invention, the HNP is an ionomer and / or an acid precursor thereof, which is preferably fully or partially neutralized with an organic acid copolymer or salt thereof. The acid copolymer is preferably an α-olefin, such as ethylene, a C _3-8 α, β-ethylenically unsaturated carboxylic acid, such as an acrylic or methacrylic acid copolymer. These may optionally contain softening monomers such as alkyl acrylates and alkyl methacrylates. However, the acryl group comprises 1 to 8 carbon atoms.
x

The acid copolymer can be described as an E / X / Y copolymer, where E is ethylene, X is an α, β-ethylenically unsaturated carboxylic acid, and Y is a softening comonomer. In a preferred embodiment, X is acrylic acid or methacrylic acid and Y is a C _1-8 alkyl acrylate or methacrylate ester. X is preferably present in an amount of from about 1 to about 35% by weight of the polymer, more preferably from about 5 to about 30% by weight of the polymer, and most preferably from about 10 to about 20% by weight of the polymer. Y is preferably present in an amount of from about 0 to about 50% by weight of the polymer, more preferably from about 5 to about 25% by weight of the polymer, most preferably from about 10 to about 20% by weight of the polymer.

  Specific acid-containing ethylene copolymers include, but are not limited to, 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 / acrylic acid / methyl acrylate, ethylene / methacrylic acid / methyl acrylate, ethylene / methacryl Acid / methyl methacrylate and ethylene / acrylic acid / n-butyl methacrylate. Preferred acid-containing ethylene copolymers are ethylene / methacrylic acid / n-butyl acrylate, ethylene / acrylic acid / n-butyl acrylate, ethylene / methacrylic acid / methyl acrylate, ethylene / acrylic acid / ethyl acrylate, ethylene / methacrylic acid / ethyl acrylate. And ethylene / acrylic acid / methyl acrylate copolymers. The most preferred acid-containing ethylene copolymers are ethylene / (meth) acrylic acid / n-butyl acrylate, ethylene / (meth) acrylic acid / ethyl acrylate, and ethylene / (meth) acrylic acid / methyl acrylate copolymers.

  The ionomer is typically neutralized by metal cations such as Li, Na, Mg, K, Ca, or Zn. By adding enough organic acid or salt of organic acid, along with an appropriate base, to the acid copolymer or ionomer, the ionomer is neutralized to a much higher level relative to the metal cation without sacrificing processability. The Preferably, the acid moiety is neutralized by about 80% or more, preferably 90-100% neutralized, most preferably 100% neutralized. However, workability is not impaired. This involves melt blending an α, β-ethylenically unsaturated carboxylic acid copolymer with, for example, an organic acid or a salt of an organic acid, and then adding a sufficient amount of cation source to add all acid moieties (acid copolymer and organic acid). Of the acid moiety) is increased by more than 90% (preferably more than 100%).

  The organic acids of this invention are aliphatic, mono- or multi-functional (saturated, unsaturated or polyunsaturated) organic acids. These organic acid salts can also be used. The salt of the organic acid of the present invention is barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium. Salts, salts of fatty acids, in particular salts of stearic acid, behenic acid, erucic acid, oleic acid, linoleic acid or dimerized derivatives thereof. The organic acids and salts of the present invention are relatively non-migratory (no blooming on the surface of the polymer under normal pressure) and non-volatile (do not evaporate at the temperature required for melt blending) preferable.

  The ionomers of this invention may also be more conventional ionomers, i.e. partially neutralized with metal cations. The acid portion of the acid copolymer may be from about 1 to about 100%, preferably from at least about 40, depending on the cation, such as lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc, aluminum or mixtures thereof. About 100%, more preferably at least about 90 to about 100% neutralized to produce an ionomer.

  In a preferred embodiment, the single layer core of the present invention is surrounded by two cover layers, and the thickness of the inner cover layer is from about 0.01 inches to about 0.06 inches, more preferably from about 0.015 inches to about 0. 0.040 inches, most preferably from about 0.02 inches to about 0.035 inches, and the inner cover layer has a Shore D hardness of greater than about 55, more preferably greater than about 60, and most preferably greater than about 65. Manufactured from large, partially or fully neutralized ionomers. In this embodiment, the thickness of the outer cover layer is from about 0.015 inches to about 0.055 inches, more preferably from about 0.02 inches to about 0.04 inches, and most preferably from about 0.025 inches to about 0. 0.035 inch and its hardness should be about Shore D60 or less, more preferably about 55 or less, and most preferably about 52 or less. The inner cover layer needs to be harder than the outer cover layer. In this embodiment, the outer cover layer has a partially or fully neutralized ionomer, polyurethane, polyurea, or blend thereof. The most preferred outer cover layer is castable or reactive injection molded polyurethane, polyurea, or a hybrid thereof, with a Shore D hardness of about 40 to about 50. The most preferred inner cover layer material is a partially neutralized ionomer having an ionomer neutralized with zinc, sodium, or lithium, such as SURLYN ™ 8940, 8945, 9910, 7930, 7940 or blends thereof The Shore D hardness is about 63 to about 68.

  In other multilayer cover, single core embodiments, the outer cover and inner cover layers are the same material and thickness, but the hardness range is reversed. That is, the outer cover layer is harder than the inner cover layer.

  In an alternative preferred embodiment, the golf ball is a one-piece golf ball having a dimple surface, the surface hardness of which is less than or equal to the center hardness (ie, a negative hardness gradient). Preferably, the one-piece ball has a diameter of about 1.680 inches to about 1.690 inches, a weight of about 1.620 ounces, an Atti compression of about 40 to 120, and a COR of about 0.750 to about 0.825. It is.

  In a preferred two-piece ball embodiment, a single layer core with a negative hardness gradient is a single layer core with a Shore D hardness of about 20 to about 80, more preferably about 40 to about 75, and most preferably about 45 to about 70. Encapsulated in a cover material, thermoplastic or thermoset polyurethane, polyurea, polyamide, polyester, polyester elastomer, polyether-amide or polyester-amide, partially or fully neutralized ionomer, polyolefin such as polyethylene, polypropylene Polyethylene copolymers, such as ethylene-butyl acrylate or ethylene-methyl acrylate, poly (ethylene methacrylic acid) co- and terpolymers, metallocene-catalyzed polyolefins, polar group functional polyolefins, and their blends Having. The preferred cover material in the two-piece embodiment is an ionomer (ordinary or HNP) having a hardness of about 50 to about 70 Shore D. In the two-piece embodiment, another preferred cover material is a thermoplastic or thermoset polyurethane or polyurea. Preferred ionomers are high acid ionomers having a copolymer of ethylene and methacrylic acid or acrylic acid and having an acid content of at least 16 to about 25 weight percent. In this case, the spin reduction caused by the relatively strong, high acid ionomer is offset to some extent by the negative gradient core that increases spin. The core diameter may be from about 1.0 inch to about 1.64 inch, preferably from about 1.30 inch to about 1.620 inch, and most preferably from about 1.40 inch to about 1.60 inch.

  Other preferred cover materials have a castable or reactive injection moldable polyurethane, polyurea, or polyurethane / polyurea copolymer or hybrid. Preferably, the cover is thermoset but may be thermoplastic and has a Shore D hardness of about 20 to about 70, more preferably about 30 to about 65, and most preferably about 35 to about 60. is there. Covers water vapor barrier layers, such as those disclosed in US Pat. Nos. 6,632,147, 6,932,720, 7,004,854, and 7,182,702 Adopt as an option between layer and core. These patent documents are incorporated herein by reference.

  Although any of the embodiments shown here may involve any known number of dimples and patterns, the preferred number of dimples is 252 to 456, more preferably 330 to 392. The dimples may have any width, depth, and edge angle disclosed in the prior art, and the pattern may have a plurality of dimples with different widths, depths, and edge angles. The separation line structure of such a pattern may be a straight line or an alternate wavy separation line (SWPL: Staggered Wave Parting Line). Most preferably, the number of dimples is 330, 332, or 392, with dimple dimensions of 5 to 7. The separation line is SWPL.

  In any of these embodiments, the single layer core may be replaced with a core consisting of two or more layers. However. At least one core layer has a negative hardness gradient.

  Other things in the working examples, or all numerical ranges, quantities, values, percentages, such as those for the quantity of material, and others in the specification, even if not explicitly stated, even if the value, quantity or Even if the term “about” is not displayed in relation to a range, it can be read as if “about” is placed in front of it. Accordingly, unless indicated otherwise, the numerical parameters set forth in the specification and claims are approximate, depending on the desired characteristics that are contemplated by the present invention. Change. At a minimum, of course, it does not limit the application of the doctrine of equivalents, but each number of parameters should be interpreted in the light of the number of significant digits recorded and the normal rounding process.

  Although the numerical ranges and parameters that represent the broad scope of this invention are approximate, the numerical values shown in the examples were recorded as accurately as possible. Any numerical value nevertheless includes errors necessarily resulting from the standard deviation found in each test measurement. Further, it should be understood that any combination of values, including the exemplified values, can be used where numerical ranges of various scopes are indicated.

  While it will be appreciated that the exemplary embodiments of the invention described herein will satisfy preferred embodiments of the invention, it should be understood that various modifications and other embodiments can occur to those skilled in the art. Examples of such changes include slight changes in the numerical values described above. Accordingly, the numerical values recited above and in the claims include such numerical values and include values that are close to or very close to the values described above and recited in the claims. Accordingly, the claims are intended to cover all such modifications and other embodiments, and are to be understood as falling within the spirit and scope of this invention.

It is a graph which shows the hardness of the core according to the distance from the center regarding the core of this invention and the core of a comparative example. 6 is a graph showing a preferred hardness range for the “low spin” examples of this invention. 6 is a graph showing a preferred hardness range for the “high spin” examples of this invention.

Claims (13)

An inner core with a first outer surface and a geometric center, manufactured as a whole from a first substantially uniform formulation and having a hardness of 45 Shore C to 65 Shore C;
An outer core layer disposed about the inner core, with a second outer surface and an inner surface, manufactured as a whole from a second substantially uniform formulation having a hardness of 55 Shore C to 90 The outer core layer of Shore C;
A cover layer disposed around the outer core layer,
The geometric center, the first and second outer surfaces, and the inner surface each have a hardness, and the hardness of the first outer surface is substantially the same as the hardness of the geometric center or the hardness of the inner surface; A golf ball having a negative hardness gradient that is smaller than this, and that has a hardness of the second outer surface greater than that of the inner surface to form a positive hardness gradient.   The inner core has a metal salt of a carboxylic acid in an amount of about 15 phr to about 30 phr, and about 0 when the ratio of antioxidant to initiator of the inner core is normalized to 100% activity. The golf ball of claim 1, wherein the outer core layer has a metal salt of a carboxylic acid in an amount of about 30 phr to about 45 phr.   The golf ball of claim 2, wherein the ratio of antioxidant to initiator is about 0.50 or less.   The golf ball of claim 2, wherein the initiator is 100% active and is present in an amount from about 0.25 phr to about 5.0 phr, and the antioxidant is present in an amount from about 0.2 phr to about 1 phr.   The hardness of the first outer surface is 42 Shore C to 60 Shore C, the hardness of the geometric center is 52 Shore C to 65 Shore C, and the magnitude of the negative hardness gradient is about 0 to −10. The golf ball according to claim 1.   The hardness of the second outer surface is 62 Shore C to 89 Shore C, the hardness of the inner surface is 58 Shore C to 82 Shore C, and the magnitude of the positive hardness gradient is 10 to 20 Item 10. A golf ball according to Item 1.   The golf ball according to claim 1, wherein the inner core and the outer core layer have diene rubber and an optional softening and speeding agent. An inner core manufactured generally from a first substantially uniform formulation with a first outer surface and a geometric center and having a hardness of 35 Shore C to 55 Shore C;
An outer core layer disposed about the inner core, with a second outer surface and an inner surface, manufactured as a whole from a second substantially uniform formulation having a hardness of 55 Shore C to 90 The outer core layer of Shore C;
A cover layer disposed around the outer core layer,
The geometric center, the first and second outer surfaces, and the inner surface each have a hardness, and the hardness of the first outer surface is substantially the same as the hardness of the geometric center or the hardness of the inner surface; A first negative hardness gradient smaller than this, and a hardness of the second outer surface is substantially the same as or smaller than the hardness of the inner surface to form a second negative hardness gradient Golf ball to play.   The inner core has a metal salt of a carboxylic acid in an amount of about 5 phr to about 15 phr, and the first ratio of antioxidant to initiator of the inner core is normalized to 100% activity. About 0.50 or less, and wherein the outer core layer has a metal salt of a carboxylic acid in an amount of about 25 phr to about 40 phr, and a second to the antioxidant initiator of the outer core layer. The golf ball of claim 8, wherein the ratio is about 0.40 or greater when normalized to 100% activity.   3. The golf of claim 2, wherein the first ratio of the antioxidant to the initiator is about 0.50 or greater and the second ratio of the antioxidant to the initiator is about 0.40 or less. ball.   The golf ball of claim 9, wherein the initiator is 100% active and is present in an amount from about 0.25 phr to about 5.0 phr, and the antioxidant is present in an amount from about 0.2 phr to about 1 phr.   The hardness of the first outer surface is 37 Shore C to 55 Shore C, the hardness of the geometric center is 42 Shore C to 56 Shore C, and the magnitude of the negative hardness gradient is about 0 to −5. The golf ball according to claim 8.   The hardness of the second outer surface is 58 Shore C to 82 Shore C, the hardness of the inner surface is 62 Shore C to 89 Shore C, and the magnitude of the negative hardness gradient is 0 to −10. The golf ball according to claim 8.

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