JP2008068080A - Highly neutralized acid polymer composition with low water vapor transmission rate and its use in golf balls - Google Patents

Abstract

Provided is a golf ball in which problems such as air bubbles generated during ball production and performance deterioration during use are reduced due to the hydrophilicity of a material used for the golf ball.
The present invention provides moisture resistance having a highly neutralized acid polymer having a water vapor transmission rate of 12.5 g · mil / 100 in ² / day or less, a melt flow index of 1.0 g / 10 min or more. The present invention is directed to a golf ball having at least one layer made from the composition. The golf balls of this invention are one-piece, two-piece, multilayer and wound golf balls. The composition of the present invention may be any one or more of a core layer, a cover layer, or an intermediate layer.
[Selection figure] None

Description

The present invention is directed to a polymer composition having a water vapor permeability of 12.5 g · mil / 100 in ² / day or less, a melt flow index of 1.0 g / 10 min or more, and a highly neutralized acid polymer. It has been. The present invention is also directed to the use of such compositions in golf balls.

  This application is a continuation-in-part of US patent application 11 / 270,066, filed on November 9, 2005, which is a continuation of US patent application 10 / 959,751 filed on October 6, 2004. This is a continuation-in-part application, which is a continuation-in-part of US patent application 10 / 360,233, filed February 6, 2003, now US Pat. No. 6,939,907, This is a continuation-in-part of US patent application 10 / 118,719, filed April 9, 2002 and now US Pat. No. 6,756,436, which was issued on June 26, 2001. Claims priority of filed US provisional application 60 / 301,046. These contents are incorporated herein by reference.

  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. 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 two-piece golf ball having a core and a cover, wherein at least one of the core and cover is made from a moisture resistant composition. The moisture-resistant composition has a water vapor transmission rate of 12.5 g · mil / 100 in ² / day or less, a melt flow index of 1.0 g / 10 minutes (190 ° C, 2.16 kg) or more, Having a neutralized acid polymer.

In another embodiment, the invention has an inner core layer, an outer core layer, and a cover, at least one of the inner core layer, the outer core layer, and the cover being made from a moisture resistant composition. It is aimed at multilayer golf balls. The moisture-resistant composition has a water vapor transmission rate of 12.5 g · mil / 100 in ² / day or less, a melt flow index of 1.0 g / 10 minutes (190 ° C, 2.16 kg) or more, Having a neutralized acid polymer.

In another embodiment, the invention includes a multi-layer golf having a core, an inner cover layer, and an outer cover, wherein at least one of the core, inner cover layer, and outer cover is made from a moisture resistant composition. It is aimed at the ball. The core diameter is 1.50 inches, the inner cover layer thickness is 0.025 inches to 0.060 inches, and the outer cover layer thickness is 0.025 inches to 0.090 inches. The moisture-resistant composition has a water vapor transmission rate of 12.5 g · mil / 100 in ² / day or less, a melt flow index of 1.0 g / 10 minutes (190 ° C, 2.16 kg) or more, Having a neutralized acid polymer.

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 α, β-ethylenically unsaturated monocarboxylic or dicarboxylic acids are (meth) acrylic acid, ethacrylic acid, maleic acid, crotonic acid, fumaric acid, itaconic acid. (Meth) acrylic acid is particularly preferred. As used herein, “(meth) acrylic acid” means methacrylic acid and / or acrylic acid. Similarly, “(meth) acrylate” means methacrylate and / or acrylate. Preferred acid polymers are C ₃ to C ₈ α, β-ethylenically unsaturated mono- or dicarboxylic acids and ethylene or C ₃ to C ₆ α-olefins, optionally including a softening monomer. A particularly preferred acid polymer is a copolymer of ethylene and (meth) acrylic acid.

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

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

  Suitable acid polymers may be partially neutralized prior to being neutralized to 70% or higher. Suitable partially neutralized acid polymers include, but are not limited to, E.I. I. Includes Surlyn ™ ionomers commercially available from DuPont; AClyn ™ ionomers commercially available from Honeywell International; and Iotek ™ ionomers commercially available from Exxon Mobile Chemical.

  In a specific example, the acid copolymer is E.I. I. Nuclel ™ acid copolymer commercially available from DuPont (eg Nucrel 960. Ethylene / methacrylic acid copolymer), Primacor ™ polymer (eg Primacor XUS 60758.08L and XUS 60751) commercially available from Dow Chemical. 18. Ethylene / acrylic acid copolymers containing 13.5% and 15.0% acid, respectively, and these partially neutralized ionomers.

  Additional suitable acid polymers are described, for example, in US Pat. No. 6,953,820 and US Patent Application Publication 2005/0049367, the disclosures 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 include silicone, silane and silicate derivatives and complex ligands; rare earth metal ions and compounds; alkali metals, alkaline earth metals, and transition metal metals Ions and compounds; and combinations thereof. Specific cation sources include, but are not limited to, lithium, sodium, potassium, magnesium, cesium, calcium, barium, manganese, copper, zinc, tin, rare earth metals, and combinations of these metal ions and compounds. In a specific embodiment, the cation source is calcium metal ions and compounds, zinc metal ions and compounds, and combinations thereof. In a specific aspect of this example, the equivalent percentage of calcium and / or zinc salt in the final composition is greater than or equal to 50%, based on all of the salts in the final composition, or 60 % Or more, or 70% or more, or 80% or more, or 90% or more, and the equivalent% is determined by multiplying the mole% of the cation by the valence of the cation. In other specific examples, the cation source is selected from metal ions and compounds of lithium, sodium, potassium, magnesium, calcium, zinc, and combinations thereof. Specific potassium-based cation sources include E.I. I. Oxane ™, commercially available from DuPont. Oxane is a monopersulfate, where potassium monopersulfate is a compound of the chemical formula 2KHSO ₅ · KHSO ₄ · K ₂ SO ₄ [potassium hydrogen peroxymonosulfate sulfate (5: 3: 2: 2)]. An active ingredient present as a salt element. In another specific embodiment, the cation source is selected from lithium metal ions and compounds, zinc metal ions and compounds, and combinations thereof. Suitable cation sources also include mixtures of lithium and / or zinc with other cations. Other cations suitable for mixing with lithium and / or zinc to produce HNP include, but are not limited to, “less hydrophilic” cations disclosed in US 2006/0106175; 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. In a specific aspect of this example, the percentage of lithium and / or zinc salts in the composition is 50% or more, or 55% or more, or 60, based on all of the salts in the composition. % Or more, or 65% or more, or 70% or more, or 80% or more, or 90% or more, or 95% or more, or 100%. The amount of cation source used can be readily determined based on the level of neutralization desired.

  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. 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. Preferably, an appropriate amount of one cation source selected from Ca and / or Zn ions and compounds is added to the molten acid polymer to provide acid groups of the acid polymer and optional organic acid acid groups. Neutralize at least 70% of all acid groups present, including. 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 Ca and / or Zn 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, alternatively a lower limit of 0.8 g / 10 min or 1.0 g / 10 min and 4.0 g / 10 min or 5. It is in a range having an upper limit of 0 g / 10 minutes. For the purposes of this disclosure, the melt flow index is measured according to ASTM D1238.

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, at least one layer is manufactured from the moisture-resistant composition containing the above-mentioned HNP and having a melt flow index of 1.0 g / 10 min or more. In a golf ball having two or more layers having 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 the desired modified moment of inertia.

  The coefficient of restitution (COR) of the golf ball of the present invention is 0.800 or more, preferably 0.800 to 0.814. 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 layer may be manufactured by any suitable technique including injection molding, compression molding, molding, and reactive injection molding. Preferably, the thermosetting cover material is manufactured into a golf ball cover by a molding or reactive injection molding technique, and the thermoplastic cover material is manufactured into a golf ball cover by a compression or injection molding technique.

  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 moldable reactive materials, preferably aliphatic or aromatic thermoset polyurethanes, and aliphatic or aromatic thermoset 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, Example 2, Comparative Example 1, and Comparative Example 2
In Examples 1 and 2, compositions were prepared by mixing acid polymers selected from Clarix ™ and Iotek ™. The relative amounts of each component used are shown in Table 1. The melt flow index, flexural modulus, and Shore D hardness of each component were measured and are reported in Table 1.

  Clarix ™ and Iotek ™ are partially neutralized Na / Zn ethylene / acrylic acid ionomers with 10-15% by weight acid, respectively. Commercially available from Schulman and XXXonMobile Chemical.

The melt flow index was measured using 2.16 kg at room temperature according to ASTM D1238. The flexural modulus was measured using a flex bar, which was prepared and measured according to ASTM D790. Hardness was measured according to ASTM D2240. In the table below, “pph” is defined as parts per hundred parts of polymer.

Each of the previous compositions was injection molded to produce solid spheres of 1.55 inches (3.94 cm) in diameter. For the sphere, pressure, hardness, and COR of 125 ft / sec were measured. 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 (5)

Manufactured from a moisture resistant composition having a highly neutralized acid polymer with a water vapor transmission rate (MVTR) of 4.0 g · mil / 100 in ² / day or less, a melt flow index of 1.0 g / 10 min or more. A golf ball comprising at least one layer, wherein the highly neutralized acid polymer has from 0 wt% to 19 wt% softening monomer, based on the total weight of the polymer.   The golf ball of claim 1, wherein the cover has a thickness of 0.025 inches to 0.090 inches and is manufactured from the moisture resistant composition.   The golf ball of claim 1, wherein the moisture resistant composition has a melt flow index of 1.0 to 4.0 g / 10 minutes.   The golf ball of claim 1, wherein the acid polymer is an ethylene / acrylic acid (methacrylic acid) polymer having 0% to 19% by weight acrylic acrylate (acrylic methacrylate) based on the total weight of the polymer.   The golf ball of claim 4, wherein the moisture resistant composition further comprises an organic acid salt selected from zinc stearate and calcium stearate.