JP2008080123A - Acid polymer composition, highly neutralized, with small moisture vapor transmission, and its use for golf ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf ball, capable of preventing performance deterioration due to absorption of moisture at a core layer, a cover layer, or an intermediate layer in a yarn-wound golf ball of a one-piece, two-piece or multi-layer type. <P>SOLUTION: The acid polymer composition, highly neutralized, for a golf ball provided with at least one layer, is manufactured of moisture-resistant highly neutralized acid polymer, having a water vapor transmission of 12.5 g-mil/100 in<SP>2</SP>/day or less, and a bending elasticity modulus of 50 to 70 kpsi. It is manufactured through a process of contacting the acid polymer with a sufficient quantity of cation source based on lithium, in the existence of a melt-flow modifier to increase the neutralization level of copolymer up to 70% at least. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a composition comprising a highly neutralized acid polymer having a water vapor transmission rate of 12.5 g · mil / 100 in ² / day or less, a flexural modulus of 50 kpsi to 70 kpsi, and a golf ball thereof Is intended for use in The highly neutralized acid polymer of this invention is prepared with a cation source selected from lithium ions and compounds.

  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 highly neutralized ionomers, are a preferred group of polymers for golf ball layers due to their toughness, durability and a wide range of hardness values. However, conventional highly neutralized ionomers are hydrophilic due to the highly hydrophilic nature of the cation sources traditionally employed for ionomer neutralization, such as magnesium or magnesium salts of fatty acids. As a result of its hydrophilic nature, conventional highly neutralized ionomers absorb significant amounts of moisture, for example, 2000 to 10,000 PPM (parts per million), so that manufacturing issues such as parts during the injection molding process The problem is that bubbles are generated inside, and the performance of the golf ball is deteriorated, for example, the ion aggregation is plasticized by water molecules and the coefficient of restitution (COR) and rigidity are reduced. Degraded performance.

  Accordingly, there remains a need for compositions that include highly neutralized acid polymers and have improved water vapor transmission rates. The present invention describes such compositions and their use in golf ball core and cover layers.

In one embodiment, the present invention is directed to a golf ball comprising at least one layer made from a moisture resistant composition. The moisture resistant composition has a water vapor transmission rate (MVTR) of 12.5 g · mil / 100 in ² / day or less, the flexural modulus of the moisture resistant composition is from 50 kpsi to 70 kpsi, and the moisture resistant composition is highly Having a neutralized acid polymer. The highly neutralized acid polymer is based on the total weight of the copolymer, from 80 wt% to 90 wt% olefin selected from ethylene and propylene and from 10 wt% to 20 wt% α, β-ethylenically unsaturated A salt of a copolymer consisting of carboxylic acid and 0 to 10 wt% of a softening monomer. The α, β-ethylenically unsaturated carboxylic acid is selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. The softening monomer is selected from methyl acrylate, propyl acrylate, and butyl acrylate. A highly neutralized acid polymer is obtained by contacting the copolymer with a sufficient amount of a cation source based on lithium in the presence of a melt flow modifier to bring the level of neutralization of the copolymer to at least 70%. Manufactured by a process that includes increasing.

In another embodiment, the present invention is directed to a golf ball comprising at least one layer made from a moisture resistant composition. The moisture-resistant composition has a water vapor transmission rate (MVTR) of 5.0 g · mil / 100 in ² / day or less, the moisture-resistant composition has a flexural modulus of 50 kpsi to 70 kpsi, and the moisture-resistant composition has a high Having a neutralized acid polymer. The highly neutralized acid polymer consists of 74 wt% to 85 wt% ethylene, 15 wt% to 16 wt% acrylic acid, and 0 wt% to 10 wt% softening monomer, based on the total weight of the copolymer. A salt of the copolymer. The softening monomer is selected from methyl acrylate and butyl acrylate. Highly neutralized acid polymers increase the level of neutralization of the copolymer to 100% by contacting the copolymer with a sufficient amount of a cation source based on lithium in the presence of a melt flow modifier. Manufactured by a process including

Detailed Description of the Invention

  The golf balls of the present invention include one-piece, two-piece, multilayer and wound golf balls, which have various core structures, intermediate layers, covers and coatings. A golf ball core may be the only single layer with the entire core from the center to the outer perimeter, and may have a center and at least one outer cover layer surrounding it. The innermost part of the center and core is preferably solid, but may be hollow, liquid filled, gel filled or gas filled. The outer core layer may be a solid or a wound layer made from a stretched elastic material. Golf ball covers may include a double cover with one or more layers, eg, an inner and outer cover layer. Optionally, additional layers may be placed between the core and the cover.

  The golf ball of the present invention comprises at least one layer made from a moisture resistant composition having a highly neutralized polymer, as disclosed herein. The moisture resistant composition may be in any one or more of a core layer, a cover layer, or an intermediate layer disposed between the core or cover.

For the purposes of this disclosure, a composition is “moisture resistant” if the water vapor transmission rate (MVTR) of the composition is 12.5 g · mil / 100 in ² / day or less. Preferably, the composition has an MVTR of 8.0 g-mil / 100 in ² / day or less, or 6.5 g-mil / 100 in ² / day or less, or 5.0 g-mil / 100 in ² / day or less, or It is 4.0 g-mil / 100 in ² / day or less, or 2.5 g-mil / 100 in ² / day or less, or 2.0 g-mil / 100 in ² / day or less. 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.

  The moisture resistant composition of the present invention has a highly neutralized acid polymer ("HNP"). As used herein, “highly neutralized” means at least 70%, preferably at least 80%, more preferably at least 90%, more preferably at least 95%, and even more preferably 100% of its acid groups. % Refers to the acid polymer after neutralization. HNP may be neutralized by a cation, a salt of an organic acid, a suitable base of an organic acid, or a combination of two or more thereof

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

When including a softening monomer, such a copolymer is referred to as an E / X / Y type copolymer, where E is ethylene and X is a C ₃ to C ₈ α, β-ethylenic unsaturated as described above. A monocarboxylic acid or dicarboxylic acid, Y is a monomer for softening. The softening monomer is typically an alkyl (meth) acrylate, wherein the alkyl group contains 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms. Preferred E / X / Y type copolymers are those where Y is (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, methyl (meth) acrylate, and ethyl (meth) acrylate Is a copolymer. Particularly preferred are E / X / Y type copolymers wherein Y is selected from methyl acrylate, propyl acrylate, and butyl acrylate. More preferred E / X / Y type copolymers are ethylene / (meth) acrylic acid / methyl acrylate and ethylene / (meth) acrylic acid / butyl acrylate.

The amount of ethylene or C ₃ to C ₆ α-olefin in the acid copolymer is typically at least 15 wt%, preferably at least 25 wt%, more preferably at least 40 wt%, based on the total weight of the copolymer, More preferably, it is 60 wt%, more preferably 80 wt% to 90 wt%, and still more preferably 74 wt% to 85 wt%. The amount of C ₃ to C ₈ α, β-ethylenically unsaturated mono- or dicarboxylic acid in the acid copolymer is typically 1 wt%, or 3 wt%, based on the total weight of the copolymer Or 4 wt%, 5 wt%, 10 wt%, 13 wt%, or 15 wt% as the lower limit, and 20 wt%, 25 wt%, 30 wt%, or 35 wt% as the upper limit. The amount of optional softening comonomer in the acid copolymer is typically 0 wt%, or 5 wt%, with a lower limit of 10 wt%, or 20 wt%, or 30 wt%, or 35 wt%, based on the total weight of the copolymer , Or 40 wt%, or 50 wt%.

  The acid polymer may be partially neutralized prior to being neutralized to 70% or more. Suitable partially neutralized acid polymers include, but are not limited to, E.I. I. Surlyn ™ ionomer commercially available from DuPont; AClyn ™ ionomer commercially available from Honeywell International; Iotek ™ ionomer commercially available from Exxon Mobile Chemical; Contains Clarix ™ ionomers commercially available from Schulman.

  In a specific embodiment, the acid copolymer is a partially neutralized ethylene / acrylic acid copolymer prepared using a cation source based on Na or Li, such as A.I. Clarix ™ ionomer commercially available from Schulman.

  Additional suitable acid polymers are fully described, for example, in US Pat. No. 6,953,820 and US Patent Application Publication 2005/0049367, the descriptions of which are hereby incorporated by reference.

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

  Suitable cations for neutralizing the acid polymers of this invention are lithium ions and compounds. Other cations suitable for mixing with the lithium cation to produce the acid polymer of this invention include, but are not limited to, the “less hydrophilic” cation disclosed in US Patent Application Publication No. 2006/0106175. Normal cations, such as those disclosed in US Pat. Nos. 6,756,436 and 6,824,477; and cations disclosed in US Patent Application Publication No. 2005/026740. These contents are incorporated herein by reference.

  Although other cations may be included in the composition, the percentage of lithium salt in the composition is greater than 50%, or greater than 55%, based on all of the salts present in the composition, Or 60% or more, or 65% or more, or 70% or more, or 80% or more, or 90% or more, or 95% or more, or 100%. Equivalent% is determined by multiplying the cation valence by the mole% of the cation.

  The composition of the present invention comprises one or more HNPs of the invention (ie produced using a lithium-based cation source) and optionally one or more conventional HNPs (ie using a normal cation source). Manufactured). The total amount of HNP of the invention and normal HNP in the composition is preferably at least 30 wt%, more preferably at least 50 wt%, even more preferably from 50 wt% to 99.5 wt%, based on the total weight of the polymer in the composition. %. Preferably, the amount of HNP of this invention present in the composition is at least 30 wt% based on the total weight of polymer in the composition.

  The moisture resistant composition of the present invention optionally has one or more organic acids and / or salts 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. Specifically, aliphatic and monofunctional organic acids are suitable, preferably those having less than 36 carbon atoms. 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. Particularly suitable organic acid salts include those produced with a cation source selected from barium, lithium, sodium, zinc, bismuth, potassium, strontium, magnesium, calcium and combinations thereof. In a specific embodiment, the organic acid salt is selected from zinc stearate and calcium stearate. Particularly preferred is zinc stearate. 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.

  The moisture resistant composition of the present invention optionally includes one or more additives and / or one or more fillers. Suitable additives include, but are not limited to, swelling and foaming agents, optical brighteners, colorants, fluorescent agents, whitening agents, UV absorbers, light stabilizers, antifoaming agents, processing aids, mica , Talc, nanofillers, antioxidants, stabilizers, softeners, perfume ingredients, plasticizers, impact modifiers, acid copolymer waxes, and surfactants. Suitable fillers include but are not limited to inorganic fillers such as zinc oxide, titanium dioxide, tin oxide, calcium oxide, magnesium oxide, barium sulfate, zinc sulfate, calcium carbonate, zinc carbonate, barium carbonate, mica, talc, Clay, silica, lead silicate, etc .; high specific gravity metal powder fillers, such as tungsten powder, molybdenum powder, etc .; reground or ground and recycled core material; and nanofillers. The filler material may be a bifunctional filler such as zinc oxide (which can be used as a filler / acid scavenger) and titanium dioxide (which is used as a filler / lightening agent and used). In addition, examples of suitable fillers and additives include, but are not limited to, those disclosed in US Patent Application Publication 2003/0225197, the contents of which are hereby incorporated by reference.

  The moisture resistant composition of this invention optionally includes one or more non-fatty acid melt flow modifiers. Suitable non-fatty acid melt flow modifiers include polyamides, polyesters, polyacrylates, polyurethanes, polyethers, thermoplastic polyureas, polyhydric alcohols, and combinations thereof. Additional non-fatty acid melt flow modifiers suitable for use in the compositions of this invention include those described in US Patent Application Publication 2006/0063893 and US Patent Application 11/216726, the disclosure of which is Incorporated herein by reference.

  In some embodiments, the moisture resistant composition of the present invention further comprises an impact modifier. Suitable impact modifiers include, but are not limited to, alkyl (meth) acrylate homopolymers or copolymers, metallocene catalyzed and ungrafted polymers, and epoxy acrylates.

The moisture resistant composition of this invention can optionally be prepared by blending HNP with one or more additional polymers, such as thermoplastic polymers and elastomers. Examples of thermoplastic polymers suitable for blending with the HNP of this invention include, but are not limited to, polyolefins, polyamides, polyesters, polyethers, polycarbonates, polysulfones, polyacetals, polylactones, acrylonitrile-butadiene-styrene resins, polyphenylene oxides. , Polyphenylene sulfide, styrene-acrylonitrile resin, styrene maleic anhydride, polyimide, aromatic polyketone, ionomer and ionomer precursor, acid copolymer, conventional HNP, polyurethane, grafted or ungrafted metallocene catalyst polymer, single site catalyst polymerization Polymers, highly crystalline acid polymers, cationic ionomers, and combinations thereof. Specific polyolefins suitable for blending one or more linear or branched or cyclic _C 2 _{-C 40} olefin, specifically, of one or more _C 2 _{-C 40 olefins,} the C 3 _{-C 20} It is a polymer containing ethylene or propylene copolymerized with an α-olefin or a C ₃ -C ₁₀ α-olefin. Specific conventional HNPs suitable for blending are disclosed in, but not limited to, US Pat. Nos. 6,756,436, 6,894,098, and 6,953,820. One or more HNPs, the disclosures 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 are those disclosed in US Pat. No. 5,981,658, eg, column 14, lines 30-56, and US Patent Application Publication No. 2005/026740, eg, paragraph 0073 thereof. The disclosures of which are incorporated herein by reference. The blends described herein can be made by combining the reactor in series with the reactor blend by blending after the reactor, and by producing multiple types of polymers using multiple catalysts in the same reactor, Can be manufactured. The polymer may be mixed before entering the extruder or may be mixed in the extruder.

  The present invention is not limited to a specific method or apparatus for producing a moisture resistant composition. In a preferred embodiment, the composition is prepared by the following process. The acid polymer is fed to a melt extruder, such as a single or twin screw extruder. An appropriate amount of a cation source selected from Li ions and compounds is added to the molten acid polymer to provide at least all of the acid groups present, including acid groups of the acid polymer and acid groups of the optional organic acid. Neutralize 70%. Of all the acid groups present, preferably at least 80%, more preferably at least 90%, even more preferably at least 95%, more preferably at least 100% are neutralized. The acid polymer may be partially neutralized prior to contact with the cation source, preferably selected from Na and / or Li metal ions and compounds. The resulting mixture is intensively mixed before it is extruded as a strand from the mold head. Additional materials such as additives, fillers, melt flow modifiers, and impact modifiers are optionally incorporated during processing.

  Further, suitable moisture resistant compositions include, but are not limited to, compositions containing HNPs neutralized by less hydrophilic cations disclosed in US Patent Application Publication 2006/0106175, the disclosure of which The contents are incorporated herein by reference.

  In order to be processable, the moisture resistant composition of the present invention has a melt flow index of at least 0.5 g / 10 min (190 ° C., 2.16 kg). Preferably, the melt flow index of the moisture resistant composition is at least 0.8 g / 10 min, or alternatively a lower limit of 0.8 g / 10 min or 1.0 g / 10 min or 1.5 g / 10 min; The upper limit is 0 g / 10 min or 4.0 g / 10 min or 5.0 g / 10 min or 10.0 g / 10 min. For the purposes of this disclosure, the melt flow index is measured according to ASTM D1238, and the results are given in g / 10 minutes (190 ° C., 2.16 kg).

  The flexural modulus of the moisture resistant composition of this invention is preferably in the lower limit of 50 kpsi or 60 kpsi and in the range of 70 kpsi or 75 kpsi.

  Preferably, the moisture resistant composition of the present invention was impact resistant and there were no problems when a solid sphere of 1.550 inch diameter made from the composition was shot 50 times with an air gun. Equipment suitable for performing the impact resistance test includes the equipment used to measure COR, which is described below.

  The COR of the moisture resistant composition of this invention is at least 0.800, preferably at least 0.810, more preferably at least 0.820. The COR of the moisture resistant composition is measured according to the COR procedure described below on a 1.550 inch diameter solid sphere made from the moisture resistant composition. The compression of the moisture resistant composition of this invention is generally 50 to 160, as measured on a 1.550 inch diameter solid sphere made from the moisture resistant composition.

  The moisture resistant composition of the present invention can be used for various applications. For example, HMP-containing moisture resistant compositions are suitable for use in golf equipment. Golf equipment includes, but is not limited to, golf balls, golf shoes, and golf clubs.

  The golf ball of the present invention may be a spool, a one-piece, a two-piece, or a multi-layer golf ball. However, one or more layers are made from a moisture resistant composition that contains a highly neutralized polymer and has a melt flow index of 1.0 g / 10 min or more. In a golf ball having two or more layers having such a moisture resistant composition, the moisture resistant composition of one layer may be the same as or different from the moisture resistant composition of the other layer. The layer having the moisture resistant composition may be any one or more of a core layer (eg, center or outer core layer), an intermediate layer, or a cover layer. The composition of this invention may be foamed or filled with a density adjusting material to achieve a golf ball with a desired modified moment of inertia.

  The golf ball of the present invention has a coefficient of restitution (COR) of 0.780 or more, preferably 0.790 or more, and more preferably 0.800 or more. The compression of this golf ball is generally 100 or less, preferably 80 to 90.

  The golf ball core of the present invention may be a single layer, double layer, or multi-layer core and generally has an overall diameter of 1.50 inches to 1.62 inches, preferably an overall diameter of 1.50. Inches. The dual layer core of the present invention generally includes an inner core layer (or “center”) having a diameter of 0.50 to 1.55 inches and an outer core having a thickness of 0.03 to 0.25 inches A layer. The golf ball cover of the present invention is a single layer, double layer, or multilayer cover. The thickness of the single layer cover of this invention is generally 0.025 inches to 0.090 inches. The thickness of each layer of the double layer and multi-layer cover of this invention is typically 0.025 inches to 0.060 inches.

  The present invention is not limited to a specific method for producing a golf ball layer. Note that the layers may be manufactured by any suitable technique, including injection molding, compression molding, casting, and reactive injection molding. Preferably, the thermosetting cover material is manufactured into a golf ball cover by casting or reactive injection molding techniques, and the thermoplastic cover material is manufactured into a golf ball cover by compression or injection molding techniques.

  In a preferred embodiment, the present invention provides a two-piece golf ball comprising a compression molded rubber core and an injection or compression molded cover layer having the moisture resistant composition described above.

  In another preferred embodiment, the present invention provides a two-piece golf ball comprising a core and a polyurethane or polyurea cover, the core having the moisture resistant composition described above.

  In another preferred embodiment, the present invention provides a multilayer golf ball having an inner core layer, an outer core layer, and a cover comprising one or more layers. At least one of the inner core layer and the outer core layer has the moisture resistant composition described above.

  In another preferred embodiment, the present invention provides a multilayer golf ball having a core with one or more layers, an inner cover layer, and an outer cover layer. At least one of the inner cover layer and the outer cover layer has the moisture resistant composition described above.

  The golf ball of the present invention may comprise at least one layer manufactured from a composition other than the moisture resistant composition described above. Suitable materials for the golf ball core, intermediate layer and cover layer of this invention include, but are not limited to, polyethylene including, for example, low density polyethylene, linear low density polyethylene, and high density polyethylene; polypropylene; rubber reinforced olefin polymers; Ether-esters; copolyether-amides; polycarbonates; acid copolymers that do not form part of an ionomeric copolymer; plastomers; flexomers: vinyl resins, eg, those made by copolymerizing vinyl chloride with vinyl cetate, acrylic esters, or vinylidene Styrene / butadiene / styrene block copolymer; styrene / ethylene-butylene / styrene block copolymer; acrylonitrile-butadiene-styrene polymer; Polymers; dynamically vulcanized elastomers; ethylene vinyl acetate; ethylene methacrylate and ethylene ethacrylate; ethylene methacrylic acid, ethylene acrylic acid, and propylene acrylic acid; polyvinyl chloride resins; using metallocene or other single site catalysts Copolymers and homopolymers produced; polyamides, amide-ester elastomers, and ionomer and polyamide graft copolymers (including, for example, Pebax ™ thermoplastic polyether block amides commercially available from Arkema); polyphenylene oxidation Resin such as NORYL ™ commercially available from General Electric; cross-linked trans polyisoprene blend; polyurethane; Urea; polyester-based thermoplastic elastomers such as E.I. I. Hytel (TM), commercially available from DuPont de Nemours and Company, and LOMOD (TM), commercially available from General Electric; polyurethane-based thermoplastic elastomers, such as commercially available from BASF Elastollan ™; synthetic or natural rubber; partially or fully neutralized ionomers; and combinations thereof. Suitable golf ball materials and structures include, but are not limited to, those disclosed in US Pat. Nos. 6,117,025, 6,767,940, and 6,969,630, These contents may be referred to and incorporated herein.

  Particularly preferred materials for the outer cover of this invention include castable reactive materials, preferably aliphatic or aromatic thermosetting polyurethanes, and aliphatic or aromatic thermosetting polyurethanes.

  Also suitable cover layer materials and methods for making them are disclosed, for example, in US Pat. Nos. 5,484,870 and 6,835,794, the contents of which are hereby incorporated by reference. .

  For the purposes of this invention, compression is measured using an Atti compression test apparatus according to known procedures, where a piston is used to press the ball against the spring. The displacement of the piston is fixed and the displacement of the spring is measured. The measurement of spring deflection does not start at the point of contact of the ball. Rather, there is approximately a first 1.25 mm (0.25 inch) spring offset offset. A very stiff core will not deflect the spring more than 1.25 mm and zero compression is measured. The Atti compression tester is designed to measure objects with a diameter of 42.7 mm (1.68 inches). Therefore, smaller objects such as golf ball cores must fill the gaps to a height of 42.7 mm to obtain accurate measurements.

For the purposes of this invention, the COR is determined according to known procedures, in which a golf ball or golf ball subassembly (eg, a golf ball core) is moved from an air gun to a predetermined velocity (38.1 m / s for purposes of this invention). (125 ft / s)). A plurality of ballistic light screens are placed between the air cannon and the steel plate to measure the velocity of the ball. As the ball moves to the steel plate, the ball activates each light screen and measures the time on each light screen. Thereby, an incident transition time proportional to the incident speed of the ball is obtained. The ball collides with the steel plate and rebounds through multiple light screens, measuring the time interval it takes to move between the light screens. Thereby, the jumping transition time proportional to the jumping speed of the ball is obtained. COR is calculated as the ratio of the pop-out transition time interval to the incident transition time interval, COR = T _out / T _in .

Examples Note that the following examples are for illustrative purposes only. The invention is not limited in any way to the specific disclosure set forth herein.
Example 1 and Comparative Example 2
In Example 1, an ethylene / acrylic acid ionomer (15 wt% acid, partially neutralized with a Li-based cation source), lithium hydroxide, zinc stearate, and an antioxidant were mixed. Prepared. The relative amounts of each component used are shown in Table 1. The melt flow index, flexural modulus, and Shore D hardness of the composition were measured and are reported in Table 1.

Each of the previous compositions was injection molded to produce a 1.55 inch (3.94 cm) diameter solid sphere. The pressure, hardness, and COR of 125 ft / sec were evaluated for the sphere. The results are reported in Table 2.

  Note that where a lower numerical limit and an upper numerical limit are indicated here, any combination of these values may be employed.

  All patents, publications, test procedures and other reference materials cited herein, including prior art references, are hereby fully incorporated by reference to the extent not inconsistent with the present invention.

  Although exemplary embodiments of the present invention have been described in detail, it should be noted that various modifications and other embodiments can be readily devised by those skilled in the art without departing from the spirit of the invention. Accordingly, the claims are not to be limited to the examples and description shown herein, but rather, the claims are to be understood as encompassing all the novel features that are patentable in the invention. It should be noted that it includes all features that are considered equivalent by those skilled in the art to which this invention pertains.

Claims (10)

The moisture-resistant composition has at least one layer, and the moisture-resistant composition has a water vapor transmission rate (MVTR) of 12.5 g · mil / 100 in ² / day or less, and the moisture-resistant composition is bent. An elastic modulus of 50 kpsi to 75 kpsi, and the moisture resistant composition has a highly neutralized acid polymer;
The highly neutralized acid polymer is
Based on the total weight of the copolymer,
80 wt% to 90 wt% of an olefin selected from ethylene and propylene;
10 wt% to 20 wt% of an α, β-ethylenically unsaturated carboxylic acid selected from acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid;
Consisting of 0 wt% to 10 wt% of a softening monomer selected from methyl acrylate, propyl acrylate, and butyl acrylate,
A salt of a copolymer;
The highly neutralized acid polymer is obtained by contacting the copolymer with a sufficient amount of a cation source based on lithium in the presence of a melt flow modifier to reduce the level of neutralization of the copolymer by at least 70%. Manufactured by a process that includes increasing to
A golf ball wherein the coefficient of restitution (COR) of the moisture resistant composition is at least 0.800 when measured on a solid sphere having a diameter of 1.550 inches made from the moisture resistant composition .   The golf ball according to claim 1, wherein the olefin is ethylene.   The golf ball according to claim 2, wherein the α, β-ethylenically unsaturated carboxylic acid is acrylic acid or methacrylic acid.   The golf ball of claim 3, wherein the softening monomer is selected from methyl acrylate and butyl acrylate.   The golf ball of claim 1, wherein the copolymer has from 13 wt% to 18 wt% of the acid, based on the total weight of the copolymer.   The golf ball according to claim 1, wherein the moisture-resistant composition has a flexural modulus of 60 kpsi to 70 kpsi. The golf ball according to claim 1, wherein the moisture resistant composition has an MVTR of 5.0 g · mil / 100 in ² / day or less.   The golf ball of claim 1, wherein the moisture resistant composition has a melt flow index of 1.5 g / 10 minutes to 2.0 g / 10 minutes.   The golf ball according to claim 1, wherein the ball is a two-piece golf ball having a core and a cover, and the cover is manufactured from the moisture-resistant composition.   The ball has an inner core layer, an outer cover layer, and one or more intermediate layers disposed between the inner core layer and the outer cover layer, the inner core layer, the outer cover layer, and the The golf ball of claim 1, wherein at least one of the intermediate layers is made from the moisture resistant composition.