JP2007160115A - Golf ball having low modulus hnp layer and high modulus hnp layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf ball of a composition that achieves desired spin performance, feeling, and reflection coefficient by applying acid copolymer. <P>SOLUTION: The golf ball has a layer formed of a low modulus HNP composition (acid copolymer) and a layer formed of a high modulus HNP composition. For example, it has 3 layers including an inner core layer, an outer core layer and an optional intermediate core layer. It is not restricted whether which layer is formed of the low modulus HNP composition or which layer is formed of the high modulus HNP composition. The low modulus HNP composition has an acid copolymer whose modulus is highly neutralized to 1,000-50,000 psi. The high modulus HNP composition of this invention has an acid copolymer whose modulus is highly neutralized to 25,000-150,000 psi. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is directed to a golf ball having a layer produced from an HNP composition having a low elastic modulus and a layer produced from an HNP composition having a high elastic modulus. As long as both layers are present in the golf ball, this invention will identify which layer is made from a low modulus HNP composition or which layer is made from a high modulus HNP composition. , Not constrained.

  Conventional golf balls can be divided into two general classes: solids and spools. Solid golf balls include one-piece, two-piece (ie, solid core and cover), and multilayer (ie, one or more layers of solid core and / or one or more layers of cover) golf balls. A wound golf ball typically includes a solid, hollow, or liquid-filled center surrounded by a stretched elastic material and a cover.

  Golf ball core and cover layers are typically comprised of a polymer composition, which includes, for example, polybutadiene rubber, polyurethane, polyamide, ionomer, and blends thereof. Ionomers, particularly ionomers neutralized to hardness, are a preferred group of polymers for golf ball layers due to their toughness, durability and a wide range of hardness values.

  Golf ball compositions having highly neutralized acid polymers are known. For example, U.S. Patent Application Publication No. 2003/0130434 discloses the introduction of a melt-processable highly neutralized ethylene acid copolymer and an aliphatic, monofunctional organic acid into an acid copolymer; Discloses a process for producing more than 90% of all existing acid groups by neutralizing, the contents of which are incorporated herein by reference. The use of such compositions in various golf ball layers is disclosed. US Patent Application Publication No. 2005/0148725 (Patent Document 2) describes (a) an acid copolymer, (b) a high molecular weight, monomeric organic acid, (c) a thermoplastic resin, (d) a cation source, (e) A highly resilient thermoplastic composition with optional fillers is disclosed, the contents of which are incorporated herein by reference. This reference discloses one-piece, two-piece, three-piece, and multilayer golf balls having a highly resilient thermoplastic composition.

Although various applications of highly neutralized acid copolymers for golf balls have been disclosed, they have been highly neutralized to specific golf ball structures with the desired spin, feeling, and COR characteristics. There remains a need in the industry to apply acid copolymers widely. The present invention realizes such a golf ball structure by utilizing a layer manufactured from an HNP composition having a low elastic modulus and a layer manufactured from an HNP composition having a high elastic modulus.
US Patent Application Publication 2003/0130434 US Patent Application Publication 2005/0148725

  In one embodiment, the present invention is directed to a golf ball having an inner core layer, an outer core layer, and a cover layer. The inner core layer is produced from a low modulus HNP composition having a highly neutralized ethylene / acrylic (or methacrylic) acid / alkyl acrylate (or alkyl methacrylate) copolymer with a modulus of 1000 psi to 50000 psi. The outer core layer is produced from a high modulus HNP composition having a highly neutralized ethylene / acrylic (or methacrylic) acid copolymer with a modulus of 45000 psi to 150,000 psi. The modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition.

  In another embodiment, the present invention is directed to a golf ball having an inner core layer, an outer core layer, and a cover layer. The inner core layer is produced from a high modulus HNP composition having a highly neutralized ethylene / acrylic (or methacrylic) acid copolymer with a modulus of 25000 psi to 150,000 psi. The outer core layer is produced from a low modulus HNP composition having a highly neutralized ethylene / acrylic (or methacrylic) acid / alkyl acrylate (or alkyl methacrylate) copolymer with a modulus of 1000 psi to 50000 psi. The modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition.

  In another embodiment, the present invention is directed to a golf ball having an inner core layer, an outer core layer, an intermediate core layer and a cover layer disposed between the inner core layer and the outer core layer. The inner core layer has a diene rubber composition, the intermediate core layer is made from a low modulus HNP composition, and the outer core layer is made from a high modulus HNP composition. The low modulus HNP composition has a highly neutralized ethylene / acrylic (or methacrylic) acid / alkyl acrylate (or alkyl methacrylate) copolymer with a modulus of 1000 psi to 50000 psi. The high modulus HNP composition has a highly neutralized ethylene / acrylic (or methacrylic) acid copolymer with a modulus of 45,000 psi to 150,000 psi. The modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition.

  In yet another embodiment, the present invention is directed to a golf ball having an inner core layer, an outer core layer, an intermediate core layer and a cover layer disposed between the inner core layer and the outer core layer, The core layer has a diene rubber composition, the intermediate core layer is made from a high modulus HNP composition, and the outer core layer is made from a low modulus HNP composition. The high modulus HNP composition has a highly neutralized ethylene / acrylic (or methacrylic) acid copolymer with a modulus of 25000 psi to 150,000 psi. The low modulus HNP composition has a highly neutralized ethylene / acrylic (or methacrylic) acid / alkyl acrylate (or alkyl methacrylate) copolymer with a modulus of 1000 psi to 50000 psi. The modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition.

Detailed Description of the Invention

  The golf ball of the present invention comprises at least two layers produced from a highly neutralized acid polymer (“HNP”) composition. More specifically, the golf ball of the present invention includes at least one layer generated from an HNP composition having a low elastic modulus and at least one layer generated from an HNP composition having a high elastic modulus.

  As used herein, a “highly neutralized acid polymer” is at least 70% acid, preferably at least 80%, more preferably at least 90%, more preferably at least 95%, more preferably 100% acid. Refers to the acid polymer after the group has been neutralized.

  As used herein, “modulus” is the flexural modulus measured using a standard flex bar according to ASTM D790-B.

Low modulus HNP compositions The low modulus HNP compositions of this invention have an elastic modulus in the range of a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 17000 or 25000 or 28000 or 30000 or 35000 or 45000 or 50000 or 55000 psi At least one modulus of elasticity has a small HNP. In specific embodiments, the modulus of elasticity of the low modulus HNP is at least 25%, or at least 30%, or at least 35% less than the modulus of elasticity of the high modulus HNP.

The low modulus HNP of this invention is a salt of an acid copolymer. It is understood that the low modulus HNP may be a blend of two or more low modulus HNPs. The low-modulus HNP acid copolymer is an O / X / Y copolymer, where O is an α-olefin, X is a C ₃ -C ₈ α, β-ethylenically unsaturated carboxylic acid, and Y is It is a monomer for softening. O is preferably ethylene. X is preferably selected from (meth) acrylic acid, ethacrylic acid, maleic acid, crotonic acid, fumaric acid, itaconic acid. (Meth) acrylic acid is particularly preferred. As used herein, “(meth) acrylic acid” means methacrylic acid and / or acrylic acid. Similarly, “(meth) acrylate” means methacrylate and / or acrylate. Y is preferably an alkyl (meth) acrylate and the acrylic group has 1 to 8 carbon atoms. Preferred O / X / Y type copolymers are O for ethylene, X for (meth) acrylic acid, and Y for (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, methyl (meth) acrylate And a copolymer that is ethyl (meth) acrylate. More preferred O / X / Y type copolymers are ethylene / (meth) acrylic acid / n-butyl acrylate, ethylene / (meth) acrylic acid / methyl acrylate, and ethylene / (meth) acrylic acid / ethyl acrylate.

Low modulus HNP acid copolymers typically comprise at least 15 wt%, or at least 25 wt%, or at least 40 wt%, or at least 60 wt% α-olefin, based on the total weight of the copolymer. The amount of the C ₃ -C ₈ α, β-ethylenically unsaturated carboxylic acid in the acid copolymer is typically lower than 1 or 4 or 6 or 8 or based on the total weight of the copolymer 10 or 15 wt% and the upper limit is in the range of 20 or 35 or 40 wt%. The amount of softening monomer in the acid copolymer is typically 1 or 3 or 5 or 11 or 15 or 20 wt% lower limit and 23 or 25 or 30 or 35 upper limit based on the total weight of the acid copolymer. Or in the range of 50.

  Particularly suitable acid copolymers for low modulus HNP are ultra-low modulus ionomer (“VLMI-”, very low modulus ionomer) type ethylene-acid copolymers such as Surlyn ™ 6320, Surlyn ™ 8120, Surlyn (TM) 8320, Surlyn (TM) 9320. Surlyn ™ ionomer is a product of E.I. I. Commercially available from DuPont. DuPont ™ HPF 1000 and DuPont ™ HPF 2000 are also suitable. I. Commercially available from DuPont.

  Other suitable acid copolymers of low modulus HNP are, for example, US Patent Application Publication Nos. 2005/0148725, 2005/0020741, 2004/0220343, and 2003/0130434, and US Pat. Nos. 5,691,418, 6,562,906. Nos. 6,653,382, 6,777,472, 6,762,246, and 6,815,480, the contents of which are incorporated herein by reference.

  In a preferred embodiment, the low modulus HNP comprises reacting an optionally partially neutralized acid copolymer with a sufficient amount of cation source in the presence of a high molecular weight organic acid or salt thereof, Produced such that at least 80%, preferably at least 90%, more preferably at least 95%, and even more preferably 100% of all acid groups are neutralized. The acid copolymer may be reacted with a high molecular weight organic acid or salt thereof simultaneously with the cation source, or the acid copolymer may be reacted with a high molecular weight organic acid prior to adding the cation source.

  Suitable high molecular weight organic acids are aliphatic organic acids, aromatic organic acids, saturated monofunctional organic acids, unsaturated monofunctional organic acids, multiunsaturated monofunctional organic acids, and dimer derivatives thereof. . Specific examples of suitable organic acids include, but are not limited to, caproic acid, caprylic acid, capric acid, lauric acid, stearic acid, behenic acid, erucic acid, oleic acid, linoleic acid, myristic acid, benzoic acid, Including palmitic acid, phenylacetic acid, naphthalenic acid, dimer derivatives thereof, and combinations thereof. Polymeric organic acid salts include aliphatic organic acids, aromatic organic acids, saturated monofunctional organic acids, unsaturated monofunctional organic acids, multi-unsaturated monofunctional organic acids, their dimer derivatives, and their Combination salts, specifically, barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, ston, titanium, tungsten, magnesium, and calcium salts, respectively. Suitable organic acids and salts thereof are described in more detail, for example, in US Pat. No. 6,756,436, the contents of which are hereby incorporated by reference.

  Suitable cation sources include alkali metal, alkaline earth metal, and transition metal metal ions and compounds; rare earth metal ions and compounds; silicone, silane and silicate derivatives and complex ligands; and combinations thereof. Preferred cation sources are magnesium, sodium, potassium, cesium, calcium, barium, manganese, copper, zinc, tin, lithium, and rare earth metal metal ions and compounds. The acid copolymer may be at least partially neutralized prior to contacting the acid copolymer with a cation source to produce a low modulus HNP. Methods for preparing ionomers are well known and are disclosed, for example, in US Pat. No. 3,264,272, the contents of which are hereby incorporated by reference. The acid polymer may be a direct copolymer in which all monomers are added simultaneously to polymerize the polymer, which is described, for example, in US Pat. No. 4,351,931, the contents of which are incorporated herein by reference. Alternatively, the acid polymer may be a graft copolymer in which monomers are grafted onto an existing polymer, which is described, for example, in US Patent Application Publication 2002/0013413, the contents of which are hereby incorporated by reference. Incorporate.

  The low modulus HNP composition of the present invention may optionally include one or more melt flow modifiers. The amount of melt flow modifier in the composition is at least 0.1 g / 10 when the composition has a melt flow index of at least 0.1 g / 10 when measured using ASTM D-1238, Condition E, 190 ° C. with a 2160 gram weight. Minutes, preferably 0.5 g / 10 min to 10.0 g / 10 min, more preferably 1.0 g / 10 min to 6.0 g / 10 min.

  Suitable melt flow modifiers include, but are not limited to, high molecular weight organic acids and salts thereof, polyamides, polyesters, polyacrylates, polyurethanes, polyethers, polyureas, polyhydric alcohols, and combinations thereof. Suitable organic acids are aliphatic organic acids, aromatic organic acids, saturated monofunctional organic acids, unsaturated monofunctional organic acids, multiunsaturated monofunctional organic acids, and dimer derivatives thereof. Specific examples of suitable organic acids include, but are not limited to, caproic acid, caprylic acid, capric acid, lauric acid, stearic acid, behenic acid, erucic acid, oleic acid, linoleic acid, myristic acid, benzoic acid, Including palmitic acid, phenylacetic acid, naphthalenic acid, and dimer derivatives thereof. Suitable organic acids are described in more detail, for example, in US Pat. No. 6,756,436, the contents of which are hereby incorporated by reference.

  Additional melt flow modifiers suitable for use in the compositions of this invention include the non-fatty acid melt flow modifiers described in US patent applications 11/216725 and 11/216726, the disclosure of which is Incorporated herein by reference.

The low modulus HNP composition of the present invention comprises an optional additive in an amount of 50 wt% or less, or 30 wt% or less, or 15 wt% or less, and / or based on the total weight of the low modulus HNP composition Contains filler. Suitable additives and fillers include, but are not limited to, chemical expansion and foaming agents, optical brighteners, colorants, fluorescent agents, whitening agents, UV absorbers, light stabilizers, antifoaming agents, processing aids. agents, mica, talc, nano-fillers, antioxidants, stabilizers, softening agents, perfume ingredients, plasticizers, impact modifiers, TiO _2, acid copolymer wax, surfactants, and fillers, for example, zinc oxide, Includes tin, barium sulfate, zinc sulfate, calcium oxide, calcium carbonate, zinc carbonate, barium carbonate, clay, tungsten, tungsten carbide, silica, lead silicate, reground (recycled material), and mixtures thereof. Suitable additives are fully described, for example, in US Patent Application Publication 2003/0225197, incorporated herein by reference.

  The low modulus HNP composition of the present invention may optionally include a high modulus HNP.

  The hardness of the low modulus HNP composition of this invention has a lower limit in the range of 40, 50 or 55 Shore D and an upper limit of 70, 80 or 87 Shore C.

In specific examples, the water vapor transmission rate of the low modulus HNP composition is 8 g-mil / 100 in ² / day or less (ie, 3.2 g-mm / m ² day or less), or 5 g-mil / 100 in ^2. / Day or less (ie 2.0 g-mm / m ² days or less), or 3 g-mil / 100 in ² / day or less (ie 1.2 g-mm / m ² days or less), or 2 g-mil / 100 in ² / Day or less (ie 0.8 g-mm / m ² days or less), 1 g-mil / 100 in ² / day or less (ie 0.4 g-mm / m ² days or less), or less than 1 g-mil / 100 in ² / day (That is, less than 0.4 g-mm / m ² days). As used herein, water vapor transmission rate (MVTR) is given in g-mil / 100 in ² / day, measured at 20 ° C. and complies with ASTM F1249-99. In a preferred aspect of this example, the low modulus HNP composition comprises a low modulus HNP prepared using a cation source that is less hydrophilic than a conventional manganese-based cation source. Suitable water vapor resistant HNP compositions are disclosed, for example, in US Patent No. 11/270066 and US Patent Application Publication No. 2005/0267240, the contents of which are hereby incorporated by reference.

  The low elastic modulus HNP composition of the present invention is not limited to any specific manufacturing method or manufacturing apparatus. In a preferred embodiment, the composition is prepared in the following manner. Acid polymer (s), preferably VLMI-type ethylene-acid terpolymer, high molecular weight organic acid (s) or salt (s), and optionally additives / fillers simultaneously or Individually fed to a melt extruder, for example a single or twin screw extruder. Appropriate amount of cation source is added simultaneously or afterwards so that at least 80%, preferably at least 90, more preferably at least 95%, more preferably 100% of all the acid groups present are neutralized. To. Prior to the above process, the acid polymer may be at least partially neutralized. Each component is thoroughly mixed and then extruded as a strand from the mold head.

The low modulus HNP compositions of this invention may be blended with one or more additional polymers, such as thermoplastic polymers and elastomers. Examples of thermoplastic polymers suitable for blending are disclosed in, but not limited to, bimodal ionomers (eg, US Patent Application Publication No. 2004/0220343 and US Pat. Nos. 6,562,906 and 6,762,246). , The contents of which are incorporated herein by reference), rosin modified ionomers, such as those disclosed in US Patent Application Publication No. 2005/0020741, the contents of which are incorporated by reference. Flexible and resilient ethylene copolymers (such as those disclosed in US Patent Application Publication No. 2003/0114565, the contents of which are incorporated herein by reference), polyolefins, polyamides, polyesters, polyethers Polycarbonate, polysulfone, polyacetal, polylactone, acrylonitrile-butadiene-styrene resin, polyphenylene oxide, polyphenylene sulfide, styrene-acrylonitrile resin, styrene maleic anhydride, polyimide, aromatic polyketone, ionomer and ionomer precursor, acid copolymer, normal Including HNP, polyurethane, grafted or ungrafted metallocene catalyst polymer, single site catalyzed polymer, highly crystalline acid polymer, cationic ionomer, and combinations thereof. Specific polyolefins suitable for blending one or more linear or branched or cyclic _C 2 _{-C 40} olefin, specifically, of one or more _C 2 _{-C 40 olefins,} the C 3 _{-C 20} It is a polymer containing ethylene or propylene copolymerized with an α-olefin or a C ₃ -C ₁₀ α-olefin. Specific conventional HNPs suitable for blending include, but are not limited to, one or more HNPs disclosed in US Pat. Nos. 6,756,436, 6,894,098, and 6,953,820, the disclosure of which Are incorporated herein by reference. Examples of elastomers suitable for blending with the polymers of this invention include, but are not limited to, all natural and synthetic rubbers, ethylene propylene rubber ("EPR"), ethylene propylene diene rubber ("EPDM"), Styrene block copolymer rubber (eg, SI, SIS, SB, SBS, SIBS, etc., “S” is styrene, “I” is isobutylene, “B” is butadiene), butyl rubber, halobutyl rubber, isobutylene and para-alkyl Copolymers of styrene, halogenated copolymers of isobutylene and para-alkylstyrene, natural rubber, polyisoprene, copolymers of butadiene with acrylonitrile, polychloroprene, alkyl acrylate rubber, isoprene chloride rubber, acrylonitrile isoprene chloride Beam, and a polybutadiene rubber (cis and trans). Still other suitable blend polymers include those disclosed in US Pat. No. 5,981,658, eg, column 14, lines 30-56, the contents of which are incorporated herein by reference. The blends described herein can be made by combining the reactor in series with the reactor blend by blending after the reactor, and by producing multiple types of polymers using multiple catalysts in the same reactor, Can be manufactured. The polymer may be mixed before entering the extruder or may be mixed in the extruder.

  Specific suitable low modulus HNP compositions include, but are not limited to, high resiliency thermoplastic compositions disclosed in US Patent Application Publication No. 2005/0148725; US Pat. Nos. 6,653,382, 6,777,472. And the highly neutralized ethylene copolymers disclosed in US Patent Application Publication No. 2003/0130434; and the highly resilient thermoplastic elastomer compositions disclosed in US Pat. No. 6,815,480, the contents of which are incorporated herein by reference. And incorporate it here.

High modulus HNP compositions The high modulus HNP compositions of this invention have a lower limit of 25000 or 27000 or 30000 or 40000 or 45000 or 50000 or 55000 or 60000 psi and an upper limit of 72000 or 75000 or 100000 or 150,000 psi At least one modulus of elasticity has a large HNP.

The high modulus HNP of this invention is a salt of an acid copolymer. It is understood that the high modulus HNP may be a blend of two or more high modulus HNPs. Preferred acid copolymers are copolymers of α-olefins and C ₃ -C ₈ α, β-ethylenically unsaturated carboxylic acids. The acid is typically in an amount ranging from 1 or 10 or 12 or 15 or 20 wt% lower limit and 25 or 30 or 35 or 40 wt% upper limit based on the total weight of the acid copolymer. The α-olefin is preferably selected from ethylene and propylene. The acid is preferably selected from (meth) acrylic acid, ethacrylic acid, maleic acid, crotonic acid, fumaric acid, itaconic acid. (Meth) acrylic acid is particularly preferred. In a preferred embodiment, high modulus HNP has a higher acid level than low modulus HNP.

  Suitable acid copolymers include partially neutralized acid polymers. Examples of suitable partially neutralized acid polymers include, but are not limited to: I. Includes Surlyn ™ ionomers commercially available from DuPont; AClyn ™ ionomers commercially available from Honeywell International; and Iotek ™ ionomers commercially available from Exxon Mobile Chemical. Additional suitable acid polymers are described, for example, in US Pat. Nos. 6,953,820, 6,762,246, and 6,953,820 and US Patent Application Publications 2005/0049367, 2005/0020741, and 2004/0220343, Their contents are incorporated herein by reference.

  In a preferred embodiment, the high modulus HNP reacts the acid copolymer with a sufficient amount of cation source to provide at least 80%, preferably at least 90%, more preferably at least 95% of all acid groups, Preferably, it is produced so that 100% is neutralized. Suitable cation sources include alkali metal, alkaline earth metal, and transition metal metal ions and compounds; rare earth metal ions and compounds; silicone, silane and silicate derivatives and complex ligands; and combinations thereof. Preferred cation sources are magnesium, sodium, potassium, cesium, calcium, barium, manganese, copper, zinc, tin, lithium, and rare earth metal metal ions and compounds. Calcium and magnesium metal ions and compounds are particularly preferred. The acid copolymer may be at least partially neutralized prior to contacting the acid copolymer with a cation source to produce a high modulus HNP. As described above, methods for preparing ionomers and acid copolymers on which ionomers are based are disclosed, for example, in US Pat. Nos. 3,264,272 and 4,351,931 and US Patent Application Publication 2002/0013413. .

  The high modulus HNP composition of the present invention may optionally include one or more melt flow modifiers. The amount of melt flow modifier in the composition is at least 0.1 g / 10 when the composition has a melt flow index of at least 0.1 g / 10 when measured using ASTM D-1238, Condition E, 190 ° C. with a 2160 gram weight. Minutes, preferably 0.5 g / 10 min to 10.0 g / 10 min, more preferably 1.0 g / 10 min to 6.0 g / 10 min.

  Suitable melt flow modifiers include, but are not limited to, high molecular weight organic acids and salts thereof, polyamides, polyesters, polyacrylates, polyurethanes, polyethers, polyureas, polyhydric alcohols, and combinations thereof. Suitable organic acids are aliphatic organic acids, aromatic organic acids, saturated monofunctional organic acids, unsaturated monofunctional organic acids, multiunsaturated monofunctional organic acids, and dimer derivatives thereof. Specific examples of suitable organic acids include, but are not limited to, caproic acid, caprylic acid, capric acid, lauric acid, stearic acid, behenic acid, erucic acid, oleic acid, linoleic acid, myristic acid, benzoic acid, Including palmitic acid, phenylacetic acid, naphthalenic acid, and dimer derivatives thereof. Suitable organic acids are described in more detail, for example, in US Pat. No. 6,756,436, the contents of which are hereby incorporated by reference.

  Additional melt flow modifiers suitable for use in the compositions of this invention include the non-fatty acid melt flow modifiers described in US patent applications 11/216725 and 11/216726, the disclosure of which is Incorporated herein by reference.

  The high modulus HNP composition of this invention is based on the total weight of the low modulus HNP composition, optionally in an amount ranging from 0, 5 or 10 wt% lower limit to 25, 30 or 50 wt% upper limit Of additives and / or fillers. Suitable additives and fillers include those described as suitable for the low modulus HNP compositions of the present invention.

  In addition to high modulus HNP, optional melt flow modifiers, and optional additives and / or fillers, the high modulus HNP compositions of the present invention may optionally include low modulus HNP.

In specific examples, the high modulus HNP composition has an MVTR of 8 g-mil / 100 in ² / day or less (ie, 3.2 g-mm / m ² days or less), or 5 g-mil / 100 in ² / day. Or less (ie 2.0 g-mm / m ² days or less), or 3 g-mil / 100 in ² / day or less (ie 1.2 g-mm / m ² days or less), or 2 g-mil / 100 in ² / day Or less (ie 0.8 g-mm / m ² days or less), 1 g-mil / 100 in ² / day or less (ie 0.4 g-mm / m ² days or less), or less than 1 g-mil / 100 in ² / day (ie 0.4 g-mm / m < ² days). In a preferred aspect of this example, the high modulus HNP composition comprises a high modulus HNP prepared using a cation source that is less hydrophilic than a conventional manganese-based cation source. Suitable water vapor resistant HNP compositions are disclosed, for example, in US Patent No. 11/270066 and US Patent Application Publication No. 2005/0267240, the contents of which are hereby incorporated by reference.

  The high elastic modulus HNP composition of the present invention is not limited to any specific manufacturing method or manufacturing apparatus. In a preferred embodiment, the composition is prepared in the following manner. The acid polymer (s), preferably ethylene / (meth) acrylic acid copolymer, optional throat flow modifier, and optional additives / fillers, either simultaneously or separately, are melt-extruded, eg, single or twin screw extrusion Supply to the machine. Appropriate amount of cation source is added simultaneously or afterwards so that at least 80%, preferably at least 90, more preferably at least 95%, more preferably 100% of all the acid groups present are neutralized. To. Prior to the above process, the acid polymer may be at least partially neutralized. Each component is thoroughly mixed and then extruded as a strand from the mold head.

  In another embodiment, a low modulus HNP is mixed with a sufficient amount of one or more additional materials (including but not limited to additives, fillers, and polymeric materials) to provide elasticity. The high modulus HNP composition is produced such that the modulus is increased and the final composition has the modulus as described for the high modulus HNP composition.

  The HNP composition of this invention may be blended with one or more additional polymers, such as thermoplastic polymers and elastomers. Examples of thermoplastic polymers and elastomers suitable for blending include those described as suitable for blending into the low modulus HNP compositions of the present invention.

Application to Golf Ball The golf ball of the present invention has at least one layer made from a low modulus HNP composition and at least one layer made from a high modulus HNP composition. In a preferred embodiment, the present invention provides a golf ball comprising a dual core and a cover, wherein the dual core is formed from a low modulus HNP composition, and a high modulus HNP composition. And a layer generated from the object.

  Suitable cover layer materials for the golf balls disclosed herein include, but are not limited to, ionomer resins and blends thereof (specifically Surlyn ™ ionomers), polyurethanes, polyureas, (meth) acrylic acids, heat Includes plastic rubber polymers, polyethylene, and synthetic or natural vulcanizates such as balata. When used as a cover layer material, polyurethanes and polyureas may be thermoset or thermoplastic. Thermosetting materials can be manufactured into golf ball layers by conventional casting or reactive injection molding techniques. Thermoplastic materials can be manufactured into golf ball layers by conventional compression or injection molding techniques. Light stable polyurea or polyurethane is preferred as the material for the outer cover layer. Other suitable cover and rubber core materials are disclosed, for example, in US Patent Application Publication No. 2005/0164810, US Patent No. 5919100 and PCT Publications WO00 / 23519 and WO00 / 29129, the contents of which are hereby incorporated by reference. Incorporate. In one embodiment of the invention, the golf ball is provided with a single layer cover, and the cover layer material is preferably selected from polyurethane and polyurea. In embodiments of the invention, the golf ball is provided with a double cover, the inner cover layer is preferably a high modulus thermoplastic material, and the outer cover layer is preferably selected from polyurethane and polyurea. .

  The present invention is not limited to any specific method for manufacturing the golf ball layer. The layer can be manufactured by any suitable technique, including injection molding, compression molding, casting, and reactive injection molding.

  In embodiments disclosed herein, the low modulus HNP composition and / or the high modulus HNP composition is foamed or filled with a density adjusting material to achieve desired golf ball performance characteristics. Can be.

  The golf ball core of the present invention comprises a dual core and a multi-layer core and typically has an Atti compression of less than 100, preferably a lower limit of 20 or 50 and an upper limit of 80 or 90 or 100 With Atti compression inside. The golf ball core of the present invention has a coefficient of restitution ("COR") of at least 0.75, preferably at least 0.78, more preferably at least 0.79. The COR used here is defined as the ratio of the rebound velocity to the input velocity when the ball is launched onto the rigid plate. In determining the COR, the input speed is understood to be 125 ft / s.

  The golf ball of this invention typically has an Atti compression of less than 120, preferably a lower limit of 60 or 75 and an upper limit of 105 or 110 or 120. The golf ball of the present invention typically has a coefficient of restitution ("COR") of 125 ft / s, at least 0.75, preferably at least 0.78, and more preferably at least 0.79.

In one embodiment of a dual core / single cover golf ball , the invention includes an inner core layer made from a low modulus HNP composition, an outer core layer made from a high modulus HNP composition, and A golf ball having a single layer cover is realized. In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The outer core layer thickness has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.310 or 0.440 or 0.560 inches; the cover thickness has a lower limit of 0.00. 020 or 0.025 or 0.030 inches with an upper limit in the range of 0.065 or 0.080 or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less. According to yet another aspect of this example, the low modulus HNP modulus of the composition of the inner core layer has a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 17000 or 28000 or 30000 or 50000 psi, The elastic modulus of the high modulus HNP of the composition of the outer core layer has a lower limit of 45000 or 55000 or 60000 psi and an upper limit of 72000 or 75000 or 100,000 or 150,000 psi.

  In another embodiment, the invention provides a golf ball having an inner core layer made from a high modulus HNP composition, an outer core layer made from a low modulus HNP composition, and a single layer cover. Realize. In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The outer core layer thickness has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.310 or 0.440 or 0.560 inches; the cover thickness has a lower limit of 0.00. 020 or 0.025 or 0.030 inches with an upper limit in the range of 0.065 or 0.080 or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of at least 80, more preferably a lower limit of 80 or 90 or 100 and an upper limit of 130 or 140. According to yet another aspect of this embodiment, the high modulus HNP modulus of the composition of the inner core layer has a lower limit of 25000 or 27000 psi and an upper limit of 72000 or 75000 or 100000 or 150,000 psi, and the outer core The elastic modulus of the low modulus HNP of the layer composition ranges from a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 28000 or 30000 or 50000 psi.

Dual Core / Double Cover Golf Ball In another embodiment, the invention includes an inner core layer made from a low modulus HNP composition, an outer core layer made from a high modulus HNP composition, And a golf ball having a double cover. In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the outer core layer has a lower limit in the range of 0.020 or 0.025 or 0.032 inches and an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the double cover is The lower limit is 0.020 or 0.025 or 0.060 inches and the upper limit is 0.075 or 0.090 or 0.110 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less. According to yet another aspect of this example, the low modulus HNP modulus of the composition of the inner core layer has a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 17000 or 28000 or 30000 or 50000 psi, The elastic modulus of the high modulus HNP of the composition of the outer core layer has a lower limit of 45000 or 55000 or 60000 psi and an upper limit of 72000 or 75000 or 100,000 or 150,000 psi.

  In another embodiment, the present invention provides a golf ball having an inner core layer made from a high modulus HNP composition, an outer core layer made from a low modulus HNP composition, and a double cover. To do. In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches with a range of 1.550 or 1.570 or 1.580 inches; the outer core The layer thickness ranges from 0.020 or 0.025 or 0.032 inches at the lower limit and 0.310 or 0.440 or 0.560 inches at the upper limit; 0.020 or 0.025 or 0.060 inches with an upper limit in the range of 0.075 or 0.090 or 0.110 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of at least 80, more preferably a lower limit of 80 or 90 or 100 and an upper limit of 130 or 140. According to yet another aspect of this embodiment, the high modulus HNP modulus of the composition of the inner core layer has a lower limit of 25000 or 27000 psi and an upper limit of 72000 or 75000 or 100000 or 150,000 psi, and the outer core The elastic modulus of the low modulus HNP of the layer composition ranges from a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 28000 or 30000 or 50000 psi.

Multi-core golf ball In accordance with the present invention, in some embodiments, the use of a low modulus HNP-based layer and a high modulus HNP-based layer eliminates the need for a normal rubber-based layer. I found out that However, it will be appreciated that in some embodiments of the invention it may be preferable to include a conventional rubber-based layer.

Accordingly, in one embodiment, the present invention provides a golf ball having:
(A) an inner core layer having a rubber composition (b) an intermediate core layer produced from a low modulus HNP composition, (c) an outer core layer produced from a high modulus HNP composition, and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less. According to yet another aspect of this example, the low modulus HNP modulus of the intermediate core layer composition has a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 17000 or 28000 or 30000 or 50000 psi, The elastic modulus of the high modulus HNP of the composition of the outer core layer has a lower limit of 45000 or 55000 or 60000 psi and an upper limit of 72000 or 75000 or 100,000 or 150,000 psi.

In another embodiment, the present invention provides a golf ball having:
(A) an inner core layer produced from a low modulus HNP composition; (b) an intermediate core layer having a rubber composition; (c) an outer core layer produced from a high modulus HNP composition; and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less.

In another embodiment, the present invention provides a golf ball having:
(A) an inner core layer produced from a low modulus HNP composition; (b) an intermediate core layer having a rubber composition; (c) an outer core layer produced from a high modulus HNP composition; and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less.

In another embodiment, the present invention provides a golf ball having:
(A) an inner core layer produced from a low modulus HNP composition; (b) an intermediate core layer produced from a high modulus HNP composition; (c) an outer core layer having a rubber composition; and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less.

In another embodiment, the present invention provides a golf ball having:
(A) an inner core layer having a rubber composition (b) an intermediate core layer produced from a high modulus HNP composition, (c) an outer core layer produced from a low modulus HNP composition, and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of 80 or less, or 70 or less, or 65 or less. According to yet another aspect of this embodiment, the high modulus HNP modulus of the intermediate core layer composition has a lower limit of 25000 or 27000 psi and an upper limit of 72000 or 75000 or 100000 or 150,000 psi, and the outer core The elastic modulus of the low modulus HNP of the layer composition ranges from a lower limit of 1000 or 5000 or 10,000 psi and an upper limit of 28000 or 30000 or 50000 psi.

In another embodiment, the present invention provides a golf ball having:
(A) an inner core layer produced from a high modulus HNP composition; (b) an intermediate core layer produced from a low modulus HNP composition; (c) an outer core layer having a rubber composition; and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of at least 80, preferably a lower limit of 80 or 90 or 100 and an upper limit of 130 or 140.

In another embodiment, the present invention implements a golf ball having:
(A) an inner core layer produced from a high modulus HNP composition; (b) an intermediate core layer having a rubber composition; (c) an outer core layer produced from a low modulus HNP composition; and (d) Cover comprising one or more layers

  In a specific aspect of this embodiment, the inner core layer diameter has a lower limit of 0.500 or 0.750 or 1.000 inches and an upper limit of 1.550 or 1.570 or 1.580 inches; The thickness of the intermediate core layer has a lower limit of 0.020 or 0.025 or 0.032 inches and an upper limit of 0.150 or 0.220 or 0.280 inches; the outer core layer thickness has a lower limit 0.020 or 0.025 or 0.032 inches with an upper limit in the range of 0.310 or 0.440 or 0.560 inches; the overall thickness of the cover has a lower limit of 0.020 or 0.025 or 0 0.030 inches with an upper limit in the range of 0.065, 0.080, or 0.090 inches. According to another aspect of this embodiment, the inner core layer has an Atti compression of at least 80, preferably a lower limit of 80 or 90 or 100 and an upper limit of 130 or 140.

  Rubbers suitable for the golf ball layer of this invention include, but are not limited to, natural and synthetic rubbers such as polybutadiene, polyisoprene, ethylene propylene rubber ("EPR"), ethylene propylene diene rubber ("EPDM"), styrene. Block copolymer rubber (eg, SI, SIS, SB, SBS, SIBS, etc., “S” is styrene, “I” is isobutylene, “B” is butadiene), butyl rubber, halobutyl rubber, isobutylene and para-alkylstyrene Copolymers, halogenated copolymers of isobutylene and para-alkylstyrene, copolymers of butadiene with acrylonitrile, polychloroprene, alkyl acrylate rubber, isoprene chloride rubber, acrylonitrile isoprene chloride rubber, and combinations thereof Including fast-growing. Diene rubber is preferred.

  In embodiments where the inner core layer has a rubber composition, the inner core layer is preferably made from the reaction product of rubber, crosslinker, filler, and co-crosslinker or Philly radical initiator and optionally a cis-trans conversion catalyst. The The rubber is typically selected from polybutadiene and styrene-butadiene. The cross-linking agent typically comprises a metal salt, such as an acid having 3 to 8 carbon atoms, such as a zinc or magnesium salt of (meth) acrylic acid. The free radical initiator may be any known polymerization initiator that decomposes in the cure cycle, including but not limited to dicumyl peroxide, 1,1-di- (t-butylperoxy) 3, 3, 5 -Trimethylcyclohexane, a-a bis-(-butylperoxy) diisopropylbenzene, 2,5-memethyl-2,5 di- (t-butylperoxy) hexane or di-t-butylperoxide, and mixtures thereof. Suitable types and amounts of rubbers, crosslinkers, fillers, cocrosslinkers and initiators are fully described, for example, in US Patent Application Publication No. 2003/0144087, the contents of which are hereby incorporated by reference. See also US Patent Application Publication No. 2003/0144087 for various ball structures and materials that can be used for golf balls.

In one embodiment of a wound golf ball , the present invention relates to a core, a conventional elastomeric thread wound around the core, and a conventional golf ball cover material, such as an ionomer resin, blends thereof (specifically Surlyn ™ ) Ionomer resins), thermoset polyurethanes and polyureas, thermoplastic polyurethanes and polyureas, (meth) acrylic acid, thermoplastic rubber polymers, polyurethanes, and covers made from synthetic or natural vulcanised rubber, eg balata Realize a thread wound golf ball.

  In a specific aspect of this example, the core includes an inner core layer made from a low modulus HNP composition and an outer core layer made from a high modulus HNP composition. The diameter of the inner core layer is preferably 0.500 to 1.250 inches. The thickness of the outer core layer is preferably 0.125 to 0.525 inches. The overall diameter of the core is preferably 1.000 to 1.550 inches.

  In another specific aspect of this example, the core includes an inner core layer made from a high modulus HNP composition and an outer core layer made from a low modulus HNP composition. The diameter of the inner core layer is preferably 0.500 to 1.250 inches. The thickness of the outer core layer is preferably 0.125 to 0.525 inches. The overall diameter of the core is preferably 1.000 to 1.550 inches.

  The wound golf ball of the present invention is manufactured by a known method, for example, the method disclosed in US Pat. No. 4,846,910.

＊ 曲げ弾性率はＡＳＴＭ Ｄ７９０−０３手順Ｂにより測定した。
＊＊硬度はＡＳＴＭ Ｄ２２４０により測定した。 Other Examples of Suitable HNPs The HNPs in the table below have been found to be particularly useful as low modulus HNPs and / or high modulus HNPs of the present invention.

* Flexural modulus was measured according to ASTM D790-03 Procedure B.
** Hardness was measured according to ASTM D2240.

  In an embodiment of the invention directed to a golf ball having an inner core layer or an intermediate core layer made from a low modulus HNP composition, Examples 6-9 are the lower of the inner core layer or the intermediate core layer. Particularly suitable for use as an elastic modulus HNP composition.

  In an embodiment of the invention directed to a golf ball having an outer core layer produced from a low modulus HNP composition, Examples 5-9 are used as the low modulus HNP composition of the outer core layer. Especially suitable for doing.

  In an embodiment of the present invention directed to a golf ball having an inner core layer or an intermediate core layer made from a high modulus HNP composition, Examples 1-6 are used to increase the height of the inner core layer or the intermediate core layer. Particularly suitable for use as an elastic modulus HNP composition.

  In an embodiment of the invention directed to a golf ball having an outer core layer made from a high modulus HNP composition, Examples 1-4 are used as the high modulus HNP composition of the outer core layer. Especially suitable for doing.

  When the lower limit of numerical values and the upper limit of numerical values are indicated here, it can be easily understood that these values can be used in any combination.

  All patents, publications, test procedures and other documents cited herein, including priority documents, are hereby incorporated by reference to the extent they do not conflict with the present invention.

  Although exemplary embodiments of the present invention have been specifically described, it should be noted that various other modifications will be apparent to those skilled in the art and may be easily made without departing from the spirit of the invention. Accordingly, the scope of the appended claims is not intended to be limited to the examples and description disclosed herein. The claims should be understood to cover all novel patentable features of the invention, including all features equivalent to those of ordinary skill in the art.

Claims (20)

(A) An inner core layer made from a low modulus HNP composition, wherein the low modulus HNP composition is a highly neutralized ethylene / acrylic (or methacrylic) having an elastic modulus of 1000 psi to 50000 psi. ) Having an acid / alkyl acrylate (or alkyl methacrylate) copolymer;
(B) An outer core layer made from a high modulus HNP composition, wherein the high modulus HNP composition is a highly neutralized ethylene / acrylic (or methacrylic) having a modulus of elasticity of 45000 psi to 150,000 psi. ) Having an acid copolymer;
(C) having a cover;
The elastic modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the elastic modulus of the highly neutralized copolymer of the high modulus HNP composition. Golf ball.   The elastic modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 25% less than the elastic modulus of the highly neutralized copolymer of the high modulus HNP composition. The golf ball described.   The golf ball of claim 1, wherein the highly neutralized copolymer of the low modulus HNP composition has an elastic modulus of 1000 psi to 35000 psi.   The elastic modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 25% less than the elastic modulus of the highly neutralized copolymer of the high modulus HNP composition. The golf ball described.   The golf ball according to claim 1, wherein one or both of the inner core layer and the outer core layer are foamed.   The golf ball of claim 1, wherein the low modulus HNP composition has an elastic modulus of 1000 psi to 50000 psi, and the high modulus HNP composition has an elastic modulus of 45000 psi to 150,000 psi.   The golf ball of claim 6, wherein the low modulus HNP composition has a modulus of elasticity that is at least 25% less than the modulus of elasticity of the high modulus HNP composition. ^2. The golf ball according to claim 1, wherein the HNP composition having a high elastic modulus has a water vapor transmission rate of 8 g-mil / 100 in ² / day or less (that is, 3.2 g-mm / m ² day or less).   The golf ball of claim 1, wherein the cover is a single layer having a thickness of 0.020 inches to 0.090 inches and is made from a thermoplastic or thermoset material.   The cover has two or more layers, the overall thickness of the cover is 0.020 inches to 0.110 inches, and each of the cover layers is made from a thermoplastic or thermoset material. 1. The golf ball according to 1.   The golf ball of claim 1, wherein the golf ball has an additional intermediate core layer between the inner core layer and the outer core layer, the intermediate core layer being formed from a diene rubber composition. (A) An inner core layer made from a high modulus HNP composition, wherein the high modulus HNP composition is a highly neutralized ethylene / acrylic (or methacrylic) having a modulus of elasticity of 25000 psi to 150,000 psi. ) Having an acid copolymer;
(B) an outer core layer produced from a low modulus HNP composition, wherein the low modulus HNP composition is a highly neutralized ethylene / acrylic (or methacrylic) having a modulus of 1000 psi to 50000 psi. ) Having an acid / alkyl acrylate (or alkyl methacrylate) copolymer;
(C) having a cover;
The elastic modulus of the highly neutralized copolymer of the low modulus HNP composition is at least 10% less than the elastic modulus of the highly neutralized copolymer of the high modulus HNP composition. Golf ball.   The golf ball according to claim 12, wherein one or both of the inner core layer and the outer core layer are foamed.   13. The modulus of elasticity of the highly neutralized copolymer of the low modulus HNP composition is at least 25% less than the modulus of the highly neutralized copolymer of the high modulus HNP composition. The golf ball described.   The golf ball of claim 12, wherein the high modulus HNP composition has an elastic modulus of 25000 psi to 150,000 psi, and the low modulus HNP composition has an elastic modulus of 1000 psi to 50000 psi.   The golf ball of claim 12, wherein the high modulus HNP composition has an elastic modulus of 25000 psi to 75000 psi, and the low modulus HNP composition has an elastic modulus of 1000 psi to 50000 psi.   The golf ball of claim 16, wherein the low modulus HNP composition has a modulus of elasticity that is at least 25% less than the modulus of elasticity of the high modulus HNP composition. The golf ball according to claim 12, wherein the HNP composition having a low elastic modulus has a water vapor transmission rate of 8 g-mil / 100 in ² / day or less (that is, 3.2 g-mm / m ² day or less).   The golf ball of claim 12, wherein the cover is a single layer having a thickness of 0.020 inches to 0.090 inches and is made from a thermoplastic or thermoset material.   The cover has two or more layers, the overall thickness of the cover is 0.020 inches to 0.110 inches, and each of the cover layers is made from a thermoplastic or thermoset material. 12. The golf ball according to 12.