JP5715038B2 - Dual core with zero gradient center and positive gradient outer core layer - Google Patents

Description

  The present invention relates generally to golf balls with a core comprising one or more layers, any of these layers having a “negative” or “positive” hardness gradient, a transformer gradient, or both. . More specifically, the golf ball has a core composed of two or more layers, and at least one layer, preferably the inner core layer, has a “zero hardness gradient” or “negative hardness gradient”.

  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. However, these slopes are typically very large, above 20 Shore C points and even above 25 Shore C points. The patent literature includes a number of literature that examines the hardness gradient across a 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 surface layer of the core. To provide a hardness gradient. This treatment is alleged to provide the core with two regions of different composition, the first part being a hard, resilient, central part of the core, which remains untreated, The part 2 is a soft, easily deformable core outer layer, 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 forming a hardness gradient from one core layer to another.

However, to realize a single-layer core with a shallow gradient ("positive" gradient) that becomes harder and softer from the surface to the center, and to realize an inexpensive and efficient method for manufacturing such a core. Is still desired.
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 directed to a golf ball that includes an inner core layer and an outer core layer forming a “double core”. The ball further includes an inner cover layer and an outer cover layer. The inner core layer is made from a substantially uniform rubber composition with a geometric center and a first outer surface. The outer core layer is made from a second substantially uniform composition, which may be the same as or different from the first, and is preferably different. The outer core layer has a second outer surface hardness, which is preferably different from the first.

  An inner cover layer is disposed around the core and preferably comprises an ionomer-based material. This layer preferably has a material hardness of about 60 Shore D or higher. The outer cover layer is disposed around the inner cover layer and is typically made from castable polyurea or castable polyurethane and has a material hardness of about 60 Shore D or less.

  The hardness of the first outer surface (that of the inner core) is smaller than the hardness of the geometric center (that of the inner core) to about 20 Shore C, forming an inner core layer with a negative hardness gradient. The hardness of the second outer surface (that of the outer core) is greater than the hardness of the geometric center up to about 18 Shore C, forming an outer core layer with a positive hardness gradient, and a shallow core with a positive hardness gradient. Form.

  The hardness of the first outer surface is generally less than the geometric center hardness by about 1 to about 15 Shore C and forms a negative hardness gradient of about -1 to about -15 Shore C, more preferably the first The hardness of the outer surface is less than the geometric center hardness by about 2 to about 12 Shore C and forms a negative hardness gradient of about −2 to about −12 Shore C.

  In one embodiment, the outer diameter of the inner core is about 0.5 to about 1.40 inches, more preferably about 0.8 to about 1.30 inches. The hardness at the geometric center of the core is about 55 to 82 Shore C, more preferably about 60 to 80 Shore C, and most preferably about 65 to 78 Shore C. The hardness of the inner core surface is about 50 to 82 Shore C, more preferably about 55 to 78 Shore C, and most preferably about 60 to 75 Shore C. The core surface hardness is about 82 to 98 Shore C.

  In other embodiments, the first substantially uniform rubber composition has an antioxidant to initiator ratio of about 0.40 or greater. The ionomer-based material of the inner cover layer preferably includes an ionomer of Na, Li, or Zn having an acid content of about 11 wt% to about 20 wt%. Alternatively, the ionomer-based material includes an ionomer having an acid content of about 16 wt% or higher and a maleic anhydride grafted metallocene-catalyzed polyolefin.

  The present invention also provides an inner core with a geometric center and a first outer surface positioned in the range of about 0.8 to about 1.3 inches from the geometric center Manufactured from a first substantially uniform rubber composition having an agent ratio of about 0.5 or greater; manufactured from a second substantially uniform rubber composition different from the first. And an outer core layer with a second outer surface positioned from about 1.53 to about 1.58 inches from the geometric center.

  An inner cover layer is formed around the core and includes an ionomer having an acid content of about 16 wt% or greater and a maleic anhydride grafted metallocene-catalyzed polyolefin. The outer cover layer is formed around the inner cover layer and includes castable polyurea or castable polyurethane.

  The hardness of the first outer surface is less than the hardness of the geometric center and forms a negative hardness gradient of about -1 to about -15, and the hardness of the second outer surface is 12 shores than the hardness of the inner surface of the outer core layer. An outer core layer having a large positive hardness gradient in the range up to C is formed.

FIG. 3 is a plot showing the hardness profile measured across the dual core of the golf ball of the present invention compared to the hardness profile of a conventional golf ball core.

  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 cover layer may include multiple layers. In a preferred embodiment, the core is manufactured from an inner core and an outer core, and the inner core and outer core layer is 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 can 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 at 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 or methacrylic acid, a non-metallic coagent, or a mixture thereof. Preferably, a suitable antioxidant is included in the composition. Optional softening and accelerating 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 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 ™ NEOCIS ™ 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.

Most preferred are neodymium and Koval catalyst grades from Lanxess, but all of the following may be employed. Buna CB21; Buna CB22; Buna CB23; Buna CB24; Buna CB25; Buna CB29 MES; Buna CB Nd40; Buna CB Nd40H; Buna CB Nd60; Buna CB55 Buna CB55 L; Buna CB70 B; Buna CB1220; Buna CB1221; Buna CB1203; Buna CB45. Many more suitable rubbers are available from JSR (Japan Synthetic Rubber), Ubepol sold by Ubein Sutries (Japan), BST sold by BST Elastomers (Thailand), and Indian Petrochemicals (India). NIPSU, Brazilian Petroflex, Korea LG, and South Korea Kuhmo Petrochemical sold by IPCL, Karbochem or South Africa's Karbochem.

  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 at which 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 an additional polymeric material for 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, t 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 include dicumyl peroxide (DICUP ™ R, DICUP ™ 40C and DICUP ™ 40KE) from the DICUP ™ family available from Cropton (Geo Specialty Chemicals). )including. Similar initiators are described in AcroChem, Luxess, Flexsys / Haewick, and R.C. T. T. et al. 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. T. et al. 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol) available from Vanderbilt as VANOX ™ MBPC. Other polyphenolic antioxidants include VANOX ™ T, VANOX ™ L, VANOX ™ SKT, VANOX ™ SWP, VANOX ™ 13 and VANOX ™ 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 (decylidene) -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-tert-butylphenyl) (2-hydroxy-4-methyl-5-decylphenyl) -n-butylmethane; (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-3-hydride) Carboxymethyl-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 (2-methyl-) -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; 2,2' -Ethylenebis (4-methyl-6-propylphenol); 4,4'-methylenebis (2-propyl-6-t-butylphenol); 4,4'-ethylenebis (2-methyl-6-propylphenol); 2,2'-methylenebis (5-methyl-6-t-butylphenol); and 4,4'-butylidenebis (6-t-butyl-3-methylphenol) Mu

  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.

  The antioxidant is 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 about 0.2 phr to about 1 phr, more preferably about 0.3 phr to about 0.8 phr, and most preferably about 0.4 phr to about 0.7 phr, core layer (inner core or outer Added to the preparation of the core layer). Preferably, when calculated as 100% activity, about 0.25 phr to about 1.5 phr of peroxide may be added to the core formulation, more preferably about 0.5 phr to about 1.2 phr, most preferably Preferably 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 a greater COR 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 another embodiment, 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 organic sulfur 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; '-Bis (2-aminonaphthyl) disulfide; 1,1'-bis (3-aminonaphthyl) disulfide; 1,1'-bis (3-aminonaphthyl) disulfide; 1,1'-bis (4-aminonaphthyl) ) Disulfide; 1,1′-bis (5-aminonaphthyl) disulfide; 1,1′-bis (6-aminonaphthyl) disulfide; 1,1′-bis (7-aminonaphthyl) disulfide; Bis (8-aminonaphthyl) disulfide; 1,2'-diamino-1,2'-dithiodinaphthalene; 2,3'-diamino-1,2'-dithiodinaphthalene; bis (4-chlorophenyl) disulfide; (2-chlorophenyl) disulfide; bis (3-chlorophenyl) disulfide; bis (4-bromophenyl) disulfide; bis (2-bromophenyl) Bis (3-bromophenyl) disulfide; bis (4-fluorophenyl) disulfide; bis (4-iodophenyl) disulfide; bis (2,5-dichlorophenyl) disulfide; bis (3,5-dichlorophenyl) disulfide; 2,4-dichlorophenyl) disulfide; bis (2,6-dichlorophenyl) disulfide; bis (2,5-dibromophenyl) disulfide; bis (3,5-dibromophenyl) disulfide; bis (2-chloro-5-bromophenyl) Bis (2,4,6-trichlorophenyl) disulfide; bis (2,3,4,5,6-pentachlorophenyl) disulfide; bis (4-cyanophenyl) disulfide; bis (2-cyanophenyl) disulfide Bis (4- Nitrophenyl) disulfide; bis (2-nitrophenyl) disulfide; 2,2'-dithiobenzoic ethyl; 2,2'-dithiobenzoic methyl; 2,2'-dithiobenzoic acid; 4,4'-dithioben Bis (4-acetylphenyl) disulfide; bis (2-acetylphenyl) disulfide; bis (4-formylphenyl) disulfide; bis (4-carbamoylphenyl) disulfide; 1,1′-dinaphthyl disulfide; 1,2′-dinaphthyl disulfide; 1,2′-dinaphthyl disulfide; 2,2′-bis (1-chlorodinaphthyl) disulfide; 2,2′-bis (1-bromonaphthyl) disulfide; Bis (2-chloronaphthyl) disulfide; 2,2′-bis (1-cyanonaphthyl) disulfide; , 2'-bis (1-acetyl-naphthyl) such as disulfide, is or mixtures thereof. 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 to} 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 . When R ₁ , R ₂ , R ₃ or R ₄ is substituted, the substituent may include one or more of the following substituents: hydroxy and its metal salt; mercapto and its metal salt; 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. Provided that R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ are each a carboxyl metal salt; acetate and its ester; 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 upward or downward. 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 present 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. It's okay. 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

  Without being bound by theory, the percentage of double bonds in the trans structure can be manipulated over a core comprising at least one main chain unsaturated rubber (eg, polybutadiene), plastic, or elastomer, which results in a transformer gradient. It is considered. The trans-gradient is adjusted (increase or decrease) by changing the type and amount of cis-to-trans catalyst (or softening and accelerating agent), the type and amount of peroxide, and the type and amount of co-agent in the formulation. )it can. For example, a formulation containing about 0.25 phr of ZnPCTP has a trans gradient of about 5% across the core, while a formulation containing about 2 phr of ZnPCTP has a trans gradient of about 10% or more. The transformer gradient can also be adjusted by cure time and temperature. Although lower temperatures and shorter cure times are likely to result in lower hardness gradients, the combination of many of these factors is different compared to what would be achieved when a single factor was employed. It may also result in a gradient in the direction and / or the opposite direction.

  The% trans isomer in the core can also be adjusted by adding organic sulfur compounds, such as those listed above, to the core formulation, including, but not limited to, pentachlorothiophenol, pentachlorothiophenol zinc, Includes ditolyl disulfide and diphenyl disulfide. The amount of organic sulfur and the overall state of cure will affect the amount of trans isomer produced during the core reaction. Another way to increase the trans content in the core is to introduce unsaturated rubber containing high levels of trans isomers, such as high trans content polybutadiene or high trans content polyoctenamer, into the core formulation. High trans rubber can be employed with or without organic sulfur compounds.

  In general, as the cure rate increases or increases, the level of trans content increases, which increases the concentration of peroxides and soft / fast agents, and to some extent the concentration of ZDA It is the same as it grows. Even the type of rubber affects the trans level, and those catalyzed by rare earth metals, such as Nd, have higher levels of transbutadiene than rubbers formed from Group VIII, such as Co, Ni, and Li. it can.

  The measurement of the polybutadiene trans isomer content referred to here is realized and can be realized as follows. A calibration standard is prepared by employing a polybutadiene rubber sample of at least two known trans contents (eg, high or low percent trans polybutadiene). Samples are used alone and blended to produce at least about 1.5% to 50% stepped transpolybutadiene, or to contain unknown quantities, resulting in a calibration curve of at least about 13 Include evenly spaced points.

Using a commercially available FTIR spectrometer equipped with a photoacoustic (“PAS”) cell, the PAS spectrum of each standard was acquired employing the following instrument parameters. That is, scanning at a speed of 2.5 KHz (optical speed of 0.16 cm / s), using an electronic filter of 1.2 KHz, setting to an undersampling ratio of 2 (number of laser signal zero crossings before sample collection), from 375 A minimum of 128 scans with a resolution of 4 cm ^{−1 in} the range of 4000 cm ⁻¹ together with a sensitivity setting of 1.

The cis-, trans-, and vinyl-polybutadiene peaks are found between 600-1100 cm ^{-1 in} the PAS spectrum. The original area of each of the peaks can be accumulated in trans-polybutadiene. The ratio of each peak to the total area of the three isomer peaks makes it possible to construct a calibration curve of the trans-polybutadiene area ratio versus the actual trans-polybutadiene content. The correlation coefficient (R ² ) of the calibration curve obtained must be at least 0.95.

  By filling the PAS cell with a sample containing an uncontaminated surface that has just been cut, free of mold release agent, etc., the PAS spectrum for the unknown core material at the point of interest can be obtained using the parameters described above. obtain. The area ratio of the unknown trans-polybutadiene is analyzed to determine the actual trans isomer content from the calibration curve.

  Under one known environment where barium sulfate is included, the previous method of testing the trans content will be accurate. Thus, an additional or alternative test for the polybutadiene trans content is as follows. A calibration standard is prepared by employing a polybutadiene rubber sample of at least two known trans contents (eg, high or low percent trans polybutadiene). Samples are used alone and blended to produce at least about 1.5% to 50% stepped transpolybutadiene, or to contain unknown quantities, resulting in a calibration curve of at least about 13 Include evenly spaced points.

Using an FT-Raman spectrometer equipped with a near-infrared laser, a Stokes Raman spectrum is acquired from each standard employing the following apparatus parameters. That is, sufficient laser power (typically 400-800 mW) to obtain a good signal-to-noise ratio without causing excessive heating or fluorescence, over a Raman shift spectrum of 400-4000 cm ⁻¹ , And at least 300 scans together.

A calibration curve can be constructed from the above generated data using a chemometric approach and software, eg, PLSplusIQ from Galactics Industries. An acceptable calibration is a PLS-1 curve generated using SNV (detrend) path length correction, average center data preparation, and 5 point SG second derivative over a spectral range of 1600-1700 cm ^−1. Adopted and acquired with this software. The correlation coefficient (R ² ) of the calibration curve obtained must be at least 0.95.

  The most suitable core of the golf ball of the present invention comprises an outer core layer formed on the inner core and is manufactured from a substantially uniform rubber composition. This “double core” involves an outer surface (the outer surface of the outer core layer) and a geometric center (the center point of the inner core layer). An intermediate layer, such as a casing layer (inner cover), is placed around the core, the cover layer is manufactured around the intermediate layer, and the cover is typically manufactured from castable polyurea or castable polyurethane. (Ie, the cover is castable polyurea (100% urea bond / no urethane bond); castable polyurethane (100% urethane bond / no urea bond); castable hybrid poly (urea / urethane) (All prepolymers are cured with amines with urethane linkages); and have castable hybrid poly (urethane / urea) (all prepolymers are urea linkages and cured with polyols). In a preferred embodiment, the core outer surface has a trans polybutadiene content of about 6% to 10%, the core has a trans polybutadiene content of about 1% to 3%, and the core outer surface has a trans polybutadiene content of about 1% to 3%. The content is about 6% or more greater than the central transformer content and forms a positive transformer gradient along the core diameter (ie, the surface transformer content is greater than the central transformer content. The core of the arrangement is considered to have a negative transformer slope, which is assumed here).

  As described above, the golf ball of the present invention preferably includes an inner core layer and an outer core layer to form a “double core”. The inner core preferably has a “zero” or “negative” hardness gradient. In one embodiment, the inner core has a hardness gradient of about 0 to about −20 (at Shore C point), more preferably about −1 to about −15 Shore C point, and most preferably about −2 to about −12 Shore C. It is a point.

  The outer diameter of the inner core is about 0.5 inches to about 1.40 inches, more preferably about 0.8 inches to about 1.30 inches, and most preferably about 1.00 inches to about 1.20 inches. . The hardness at the geometric center of the core is about 55 to 82 Shore C, more preferably about 60 to 80 Shore C, and most preferably about 65 to 78 Shore C. The surface hardness of the inner core layer is preferably about 50 to 82 Shore C, more preferably about 55 Shore C to 78 Shore C, and most preferably about 60 Shore C to 75 Shore C.

  In order to achieve the preferred embodiment described above, the rubber composition used to form the inner core layer is now described in further detail and is about 0.40 or more, more preferably from about 0.5. With large antioxidant to initiator ratio.

  The outer core layer preferably has a surface hardness of about 82 Shore C to about 98 Shore C, more preferably about 84 Shore C to about 95 Shore C, and most preferably about 85 Shore C to about 92 Shore C. In an alternative embodiment, the outer core layer preferably has a surface hardness of about 55 Shore D to about 75 Shore D, and most preferably about 58 Shore D to about 72 Shore D.

  The outer core layer is typically accompanied by a “positive hardness gradient”. Preferably, the hardness gradient across the outer core layer is about 16 Shore C or less, more preferably about 10 Shore C or less, and most preferably about 8 Shore C or less.

  Optionally, the dual core may include an intermediate core layer made from a thermoplastic rubber composition. Suitable rubbers and compositions made therefrom are discussed herein. The intermediate core layer may be accompanied by any hardness gradient, including “zero hardness gradient” and “negative hardness gradient” or “positive hardness gradient”.

  The core of the present invention, whether a dual core or a dual core including an optional intermediate core layer, is about 1.40 inches to about 1.64 inches, more preferably about 1.50 inches to about 1. With an outer diameter of 60 inches, most preferably from about 1.53 inches to about 1.58 inches.

  Regarding the hardness gradient, the core itself may be accompanied by an overall hardness gradient. In a preferred embodiment, the surface of the core is harder than the geometric center of the inner core layer and the hardness gradient is up to about 18 Shore C, more preferably up to about 15 Shore C, and most preferably up to about 12 Shore C.

  The inner core layer is made from a rubber composition, the transbutadiene content of which is about 10% or less, preferably about 1% to about 10%, more preferably about 2% to about 9%, most Preferably from about 4% to about 8%. The outer core layer is made from a rubber composition, and the transbutadiene content of the rubber composition is about 10% or more, more preferably about 20% or more, and most preferably about 30% or more. In order to achieve a variety of different core characteristics, the ratio of the inner core layer transformer content to the outer core layer transformer content may be varied. This ratio is preferably greater than 1.5, more preferably greater than 2.0, and most preferably greater than 3.0.

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

(*) 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

  Additionally, a number of dual cores are prepared according to the present invention, hardness measurements are taken across the cores, and the values are reported in Table 3 below. The resulting plot can be seen in FIG. All core diameters are 1.55 inches. Shore C hardness was measured in accordance with ASTM D-2240 at various points across the core cross-section. Geometric center, outer surface, 2-mm, 4-mm, 6-mm, 8-mm, 10-mm, 12-mm, 14-mm, 16-mm, and 18- The results of hardness at the mm position are shown in the table. Furthermore, the hardness data points are at (on the surface of the inner core) at or near (within about 1 mm) at the interface between the inner and outer core layers (in this example, 12.7 mm from the geometric center) and at the core. It was measured at the outer surface (19.6 mm from the geometric center in this example). Both the center of the invention and the control center were covered with the same outer core layer.

The overall core formulation is as follows. The inner core layer is about 80 phr BSTE 1220 polybutadiene rubber, about 20 phr CB23 polybutadiene rubber, 30-36 phr zinc diacrylate (forming different compressions, see FIG. 1), about 0.4 phr VANOX MBPC antioxidant. About 0.7 phr ZnPCTP, about 1 phr Perkadox BC peroxide, and ZnO to achieve a density of about 1.125 g / cc. The inner core of the control is about 85 phr BST BR1220 polybutadiene rubber, about 15 phr CB23 polybutadiene rubber, about 15 phr POLYWATE 325 (barium sulfate), about 5 phr ZnO, about 0.5 parts ZnPCTP, about 0.75 phr peroxide. Product, about 25 phr ZDA, about 1 phr AFLUX processing aid, colorant, and rigilind. The inner core layer watch is about 1.00 inches. The outer core layer includes about 78 phr BST BR1220 polybutadiene, about 13 phr CB23 polybutadiene, about 15 phr ZnO, about 0.4 phr PERKADOX BC peroxide, about 38 phr ZDA, liglind , colorant, and balata reinforcement.

The cure cycle was adjusted accordingly so that the hardness gradient across the core changed. The temperature / time criteria are about 330 ° F (166 ° C) / 20 minutes, about 335 ° F (168 ° C) / 18 minutes, about 340 ° F (171 ° C) / 16 minutes, about 345 ° F (174 ° F). ° C) / 14 minutes. The inner core of this invention was molded in about 18 minutes at 305 ° F. (152 ° C.).

  Referring to Table 3 and FIG. 1, Examples 1 to 3 all have a “negative hardness gradient” inner core layer, the magnitude of the gradient being 10 or greater (the center surface hardness is geometric centered). It is clear that it compares to hardness). Conversely, the control golf ball shows that the inner core layer is associated with a “positive hardness gradient”.

  The surface hardness of the core is taken 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 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 less than the center hardness and 12 Shore C less 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 compositions of Examples 1 and 2 are 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 components and the cure cycle are altered. Furthermore, the ratio of antioxidant to initiator changes 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 higher the antioxidant, the more peroxide initiator is required to achieve the desired compression.

  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 cores of this invention are manufactured using 305 ° F (152 ° C), 14 minutes, 315 ° F (157 ° C), 11 minutes, and 320 ° F (160 ° C), 16 minute cure cycles. It was. 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-TMXDI"); Sylene 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 ("TMDI"); tetracene diisocyanate Isocyanurates of toluene diisocyanate; naphthalene diisocyanate; anthracene diisocyanate and mixtures thereof; uretdione of hexamethylene 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” refers to 4,4′-diphenylmethane diisocyanate, polymeric MDI, carbodiimide modified liquid MDI, and mixtures thereof, and further the diisocyanate used is “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"); 4,4'-methylene-bi -(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 the present invention are 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, cut 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 the present 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 due to 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, trimethylol propane 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 about 1000 to about 3000, more preferably about 1500 to about 2500. Since low molecular weight polyether ethers tend to form solid polyureas, large molecular weight oligomers such as JEFFAMINE D2000 are 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 are 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 this 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 mixture; PMDI Ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,2-diisocyanate; tetramethylene-1,3-diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexamethylene 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; 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 (isocyanatemethyl) -cyclohexane diisocyanate; 4,4'-bis (isocyanatemethyl) dicyclohexane; '-Bis (isocyanatomethyl) dicyclohexane; isophorone diisocyanate; triisocyanate of HDI 2,2,4-trimethyl-1,6-hexane diisocyanate triisocyanate; 4,4′-dicyclohexylmethane diisocyanate; 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; -, 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-tetra Methyl xylene diisocyanate; trimerized isocyanurate of any polyisocyanate, for example, isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethyl xylene diisocyanate, hexa Isocyanurates of tylene diisocyanate, and mixtures thereof; dimerized ureizions of any polyisocyanate, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and mixtures thereof; modified from the above isocyanates and polyisocyanates 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 (isocyanatemethyl) -cyclohexane diisocyanate; 4,4′-bis (isocyanatemethyl) dicyclohexane 2,4′-bis (isocyanatomethyl) dicyclohexane; isophorone diisocyanate; Isocyanates; triisocyanates of 2,2,4-trimethyl-1,6-hexane diisocyanate; 4,4′-dicyclohexylmethane diisocyanate; 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; Contains a mixture. 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 isocyanurate of any polyisocyanate, for example, isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate of hexamethylene diisocyanate, and mixtures thereof; A dimerized ureizion 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 varying the number of unreacted NCO groups in the polyurea prepolymer of isocyanate and polyetheramine, factors such as the rate of reaction and the 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 also 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 a 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 embodiment, 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-terminal curing agents may be modified with a compatible amine-terminal freezing point depressant or mixture 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- (aminopropyl) 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; '-Bis- (sec-butylamino) -diphenylmethane and derivatives thereof; 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); '-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 derivatives; 4,4'-dicyclohexylmethanediamine; 1,4-cyclohexane-bis- (methylamine); 3-cyclohexane-bis- (methylamine); diethylene glycol di- (amino 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 layer 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.

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, and 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 / methacrylic 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 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 must be relatively non-migratory (do not cause blooming on the surface of the polymer under normal pressure) and be 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 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 that has a dimple surface and whose surface hardness 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, its weight is about 1.620 ounces, its Atti compression is about 40 to 120, and its COR is 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. A 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 herein may involve any known number of dimples and patterns, the preferred number of dimples is from 252 to 456, more preferably from 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 alternating wavy separation line (SWPL). 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 representing the broad scope of the invention are approximate, the numerical values shown in the examples were recorded as accurately as possible. Any numerical value still contains 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.

Claims (1)

An inner core made of a first substantially uniform rubber composition with a geometric center and a first outer surface;
An outer core layer made from a second substantially uniform rubber composition and having a second outer surface;
An inner cover layer disposed around the core, having an ionomer-based material and having a material hardness of 60 Shore D or more;
An outer cover layer disposed around the inner cover layer, having castable polyurea or castable polyurethane and having a material hardness of 60 Shore D or less;
The hardness of the first outer surface is smaller in the range of 20 Shore C than the hardness of the geometric center to form an inner core layer having a negative hardness gradient, and the hardness of the second outer surface is the geometric center. An outer core layer having a large positive hardness gradient in a range of up to 18 Shore C from the hardness of the inner core, and the entire core consisting of the inner core and the outer core layer has a hardness gradient from the geometric center to the second outer surface. A golf ball having a positive hardness gradient of 12 Shore C or less in the direction toward .

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