JP2010142296A - Golf ball - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a golf ball excellent in abrasion resistance and resilience. <P>SOLUTION: The golf ball includes a core and a cover covering the core. The cover is made from a cover composition including a resin composition as a resin component acquired by the reaction of: (a) a hydrogen additive of a block copolymer including at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block; (b) olefine polymer; (c) a specific silane compound; and (d) organic peroxide. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a golf ball, and more particularly, to a technique for achieving both scratch resistance and resilience.

  As a resin component constituting the golf ball cover, ionomer resin and polyurethane are used. Covers made of ionomer resin are widely used because of their excellent resilience, durability, and workability. However, they have a high rigidity and hardness, resulting in poor shot feel and sufficient spin performance. Has been pointed out, such as poor control and poor control. On the other hand, polyurethane is used as the base resin constituting the cover because the shot feeling and spin characteristics are improved as compared with the ionomer resin.

  For example, Patent Documents 1 to 3 disclose that a thermosetting polyurethane is used for the cover, and Patent Documents 4 and 5 disclose that a thermoplastic polyurethane is used for the cover. However, when thermosetting polyurethane is used for the cover, a golf ball having excellent scratch resistance can be obtained, but the manufacturing process of the golf ball is complicated. Further, golf balls using thermoplastic polyurethane as a cover are not sufficient in scuff resistance and durability compared to the case where thermosetting polyurethane is used.

As a technique for improving the scuff resistance of the cover, for example, there are Patent Documents 6 to 9. Patent Documents 6 and 7 disclose golf balls in which a cover is formed from a cover composition in which a titanate coupling agent is added to a base resin mainly composed of an ionomer resin or a thermoplastic polyurethane. . In Patent Document 8, in a golf ball comprising a core and a coating layer formed around the core, at least one of the coating layers has at least 40 cis 1, 4 structure as a layer forming material. It is formed by cross-linking a rubber composition containing α, β-unsaturated carboxylic acid, metal oxide, and polymerization initiator to a base rubber mainly composed of polybutadiene having a% or more. A golf ball is disclosed. In Patent Document 9, in a golf ball including a center and a cover disposed on the center, at least one interpenetrating polymer network is present in at least a part of the golf ball outside the center. A golf ball is disclosed.
Japanese Patent Laid-Open No. 51-74726 Japanese Patent No. 2662909 US Pat. No. 4,123,061 U.S. Pat. No. 3,395,109 U.S. Pat. No. 4,248,432 JP 2006-346014 A JP 2006-346015 A JP 2001-70478 A JP 2003-244471 A

  As a technique for improving the scratch resistance of the cover, a method of blending a coupling material with thermoplastic polyurethane or ionomer resin as a composition for the cover has been proposed, but there is room for improvement from the viewpoint of resilience. was there.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a golf ball that is excellent in abrasion resistance and resilience.

  The golf ball of the present invention that has solved the above-mentioned problems is a golf ball having a core and a cover that covers the core, wherein the cover contains (a) vinyl aromatic hydrocarbon heavy as a resin component. A hydrogenated product of a block copolymer having at least one coalescence block and at least one conjugated diene polymer block, (b) an olefin polymer, (c) a silane compound represented by the following general formula (1), and (D) It is formed from the composition for a cover containing the resin composition obtained by making an organic peroxide react.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]

  The cover composition containing the resin composition obtained by reacting the above (a) to (d) can stably retain thermoplasticity under the condition where moisture is isolated. That is, during storage in the absolutely dry state and during cover molding performed at a high temperature of 100 ° C. or higher, the cover can be easily molded because of thermoplasticity. After molding the cover, the alkoxysilane group in the cover is allowed to undergo a crosslinking reaction by hydrolysis and condensation reaction simply by leaving it in a normal temperature and humidity atmosphere (for example, temperature 20 ± 15 ° C., relative humidity 65 ± 20% RH). Thus, a three-dimensional crosslinked structure can be formed in the cover. Therefore, the scuff resistance and resilience of the cover can be improved without reducing the productivity of the golf ball.

  The cover composition is preferably obtained by further adding (f) a silanol condensation catalyst composition to the resin composition. By adding the (f) silanol condensation catalyst composition to the cover composition, the progress of the cross-linking reaction by the alkoxysilane group can be accelerated, so that workability is improved. The component (a) is preferably a hydrogenated product of a block copolymer having at least two styrene blocks as a vinyl aromatic hydrocarbon polymer block and at least one butadiene block as a conjugated diene polymer block. The block copolymer constituting the component (a) has a weight average molecular weight of 160,000 or less, and the vinyl aromatic hydrocarbon polymer block content in the block copolymer is 25% by mass to 70%. It is more preferable that it is mass%.

Wherein (b) as the component, (b-1) and the flexural modulus of the propylene polymer of 100MPa~1800MPa, (b-2) a density of 0.870g ^/ cm ³ ~0.910g ^/ cm 3 ethylene Those containing a copolymer are preferred. As the component (f), a compound having a sulfonic acid group or an organic tin compound is suitable.

  In addition to the components (a) to (d), the resin composition is preferably obtained by further reacting (e) a rubber softener. The blending ratio (total 100% by mass) of the component (a), the component (b) and the component (e) in the resin composition is (a) component / (b) component / (e) component = 20% by mass to 80% by mass / 5% by mass to 50% by mass / 1% by mass to 40% by mass are preferable, and the content of the component (c) is the total amount of the component (a), the component (b), and the component (e) 100. 0.01 mass part-10 mass parts are preferable with respect to a mass part, and content of the said (d) component is with respect to 100 mass parts of total amounts of (a) component, (b) component, and (e) component. 0.01 parts by mass to 3 parts by mass is preferable. The content of the component (f) in the cover composition is preferably 0.2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the resin composition.

  The cover composition preferably has a rebound resilience of 40% to 70%, a slab hardness of 75 to 98 in Shore A hardness, a flexural modulus of 10 MPa to 300 MPa, and a three-dimensional crosslinking ratio of 15 to 50% by weight.

  The present invention includes (a) a hydrogenated block copolymer having at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block, (b) an olefin polymer, (c) ) A step of preparing a resin composition by reacting a silane compound represented by the following general formula (1) and (d) an organic peroxide; a cover composition is prepared using the obtained resin composition; A golf ball manufacturing method comprising: a cover molding step of molding a cover from the cover composition.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]

  In the step of molding the cover, it is preferable to prepare a cover composition by further adding (f) a silanol condensation catalyst to the resin composition.

  According to the present invention, a golf ball excellent in abrasion resistance and resilience can be obtained.

  The golf ball of the present invention comprises (a) a hydrogenated block copolymer having at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block, (b) an olefin polymer, (C) It is formed from the composition for covers containing the resin composition obtained by making the silane compound represented by following General formula (1), and (d) organic peroxide react, It is characterized by the above-mentioned. To do.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]

  First, the resin composition will be described. (A) a hydrogenated block copolymer having at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block (hereinafter simply referred to as “(a) block copolymer) used in the resin composition; The polymer hydrogenated product ”is sometimes described.

  Examples of the vinyl aromatic hydrocarbon compound constituting the vinyl aromatic hydrocarbon polymer block include styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl. Styrene, 2,6-dimethylstyrene, 3,5-dimethylstyrene, p-ethylstyrene, t-butylstyrene, divinylbenzene, 1,1-diphenylethylene, vinylnaphthalene, vinylanthracene, N, N-diethyl-p- Examples include aminoethyl styrene and vinyl pyridine. These vinyl aromatic hydrocarbon compounds may be used alone or in combination of two or more. Of these, styrene compounds are preferred, and styrene is particularly preferred.

  Examples of the conjugated diene compound constituting the conjugated diene polymer block include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3. -Octadiene, 1,3-hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, and the like. These conjugated diene compounds may be used alone or in combination of two or more. Among these, 1,3-butadiene and isoprene are preferable.

  The weight average molecular weight of the block copolymer constituting the hydrogenated product of the block copolymer (a) is preferably 160,000 or less, more preferably 140,000 or less, and still more preferably 120,000 or less.

  The content of the vinyl aromatic hydrocarbon polymer block in the block copolymer constituting the hydrogenated product of the block copolymer (a) is preferably 25% by mass or more, more preferably 28% by mass or more, 70 mass% or less is preferable, More preferably, it is 65 mass% or less. When the content of the vinyl aromatic hydrocarbon polymer block in the block copolymer is within the above range, the resilience characteristics of the hydrogenated product of (a) the block copolymer alone are good.

  Specific examples of the hydrogenated product of the block copolymer (a) include, for example, at least two styrene blocks as vinyl aromatic hydrocarbon polymer blocks and at least one butadiene block as conjugated diene polymer blocks. Hydrogenated block copolymer (styrene-ethylene / butylene-styrene (SEBS)), at least two styrene blocks as vinyl aromatic hydrocarbon polymer blocks, and at least one isoprene block as conjugated diene polymer blocks Examples thereof include a hydrogenated block copolymer (styrene-ethylene / propylene-styrene (SEPS)). Among these, SEBS is particularly preferable as the hydrogenated product of the block copolymer (a).

  Specific examples of the hydrogenated product of the block copolymer (a) are illustrated by trade names: “KRATON (registered trademark) G”, “KRATON D” manufactured by Kraton Polymer, and “Septon (registered trademark)” manufactured by Kuraray. ) "," Tuftec (registered trademark) "manufactured by Asahi Kasei Chemicals Corporation.

  The (b) olefin polymer used for the resin composition will be described.

  The (b) olefin polymer is not particularly limited, but ethylene, propylene, 1-butene, 2-methyl-1-butene, 1-pentene, 2-methyl-1-pentene, 1- Hexene, 2,2-dimethyl-1-butene, 2-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 2-methyl-1-hexene, 3-methyl-1-hexene, 2, 2-dimethyl-1-pentene, 3,3-dimethyl-1-pentene, 2,3-dimethyl-1-pentene, 3-ethyl-1-pentene, 2,2,3-trimethyl-1-butene, 1- Preferred are olefin homopolymers or copolymers such as octene, 2,2,4-trimethyl-1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene. The copolymer may be a random copolymer or a block copolymer, but a random copolymer is preferred. Moreover, the (b) olefin polymer may contain monomer components other than the above-mentioned olefins to the extent that the effects of the present invention are not impaired.

The (b) olefin polymer includes (b-1) a propylene polymer having a flexural modulus of 100 MPa to 1800 MPa, and (b-2) a density of 0.870 g / cm ^{3 to} 0.910 g / cm ³ . It is preferable to contain an ethylene copolymer.

  The propylene polymer (b-1) having a flexural modulus of 100 MPa to 1800 MPa (hereinafter sometimes simply referred to as “(b-1) propylene polymer”) has a propylene component content in the polymer. If it is 50 mass% or more and the bending elastic modulus is 100 MPa to 1800 MPa, it is not particularly limited.

  The bending elastic modulus of the (b-1) propylene polymer is 100 MPa to 1800 MPa. (B-1) The flexural modulus of the propylene-based polymer is more preferably 500 MPa or more, further preferably 800 MPa or more, and preferably 1800 MPa or less. In addition, the flexural modulus of the (b-1) propylene-based polymer is a value measured according to JIS K 7171.

  The melt flow rate (230 ° C., 2.16 kg load) of the (b-1) propylene polymer is preferably 20 g / 10 min or less, more preferably 10 g / 10 min or less. In addition, the melt flow rate (230 degreeC, 2.16kg load) of (b-1) propylene-type polymer is the value measured according to JISK7210.

  Specific examples of the (b-1) propylene-based polymer are illustrated by trade names: “NOVATEC (registered trademark) PP” manufactured by Nippon Polypro Co., Ltd., “Sun Aroma (registered trademark) PP” manufactured by Sun Allomer, Prime Polymer Co., Ltd. “Prime Polypro (registered trademark)” manufactured by the same company.

Wherein (b-2) density of 0.870g ^/ cm ³ ~0.910g ^/ cm 3 of ethylene copolymer (hereinafter referred to simply as "(b-2) ethylene copolymer") is and the content of ethylene component in the polymer is not less than 50 wt%, the density is not particularly limited as long as the ^{0.870g / cm 3 ~0.910g / cm 3} .

Density of the (b-2) The ethylene copolymer is ^{0.870g / cm 3 ~0.910g / cm 3} . (B-2) the density of the ethylene copolymer is if ^{0.870g / cm 3 ~0.910g / cm 3} , a slab hardness of the cover composition is improved. In addition, the density of (b-2) ethylene-type polymer is the value measured according to JISK7112.

  The melt flow rate (190 ° C., 2.16 kg load) of the (b-2) ethylene polymer is preferably 5 g / 10 min or more, more preferably 10 g / 10 min or more. In addition, the melt flow rate (190 degreeC, 2.16kg load) of (b-2) ethylene-type polymer is the value measured according to JISK7210.

  Specific examples of the (b-2) ethylene-based polymer are exemplified by trade names: “Novatech (registered trademark)” and “Kernel (registered trademark)” manufactured by Nippon Polyethylene Co., Ltd., “engage ( ENGAGE) (registered trademark), “Tafmer (registered trademark)” manufactured by Mitsui Chemicals, and the like.

  When the (b) olefin polymer contains (b-1) a propylene polymer and (b-2) an ethylene polymer, their blending ratio (100% by mass in total) is (b -1) propylene polymer / (b-2) ethylene polymer = 1% by mass to 99% by mass / 99% by mass to 1% by mass, more preferably 5% by mass to 95% by mass / 95% by mass It is -5 mass%, More preferably, it is 10 mass%-90 mass% / 90 mass%-10 mass%. Moreover, the aspect in which (b) olefin polymer consists only of (b-1) propylene polymer and (b-2) ethylene polymer is also preferable.

  The (c) silane compound represented by the following general formula (1) (hereinafter sometimes simply referred to as “(c) silane compound”) used in the resin composition will be described.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]

In the general formula (1), the ethylenically unsaturated hydrocarbon group represented by R ¹ is not particularly limited as long as it has radical reactivity, and may have an oxygen atom. Examples of the ethylenically unsaturated hydrocarbon group include an alkenyl group having 2 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, a (meth) acryl group, a (meth) acryloyl group, and the like. Among these, a vinyl group, an allyl group, an isopropenyl group, a butenyl group, and a γ- (meth) acryloxypropyl group are preferable. In addition, in this application, (meth) acryl shows an acryl and / or methacryl.

Examples of the alkyl group having 1 to 12 carbon atoms represented by R ² include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Is mentioned. Examples of the hydrolyzable group represented by Y include alkoxy groups such as a methoxy group, an ethoxy group, and a propoxy group; a formyloxy group, an acetoxy group, a propionyloxy group, an arylamino group, and the like. Groups are preferred.

  As said (c) silane compound, the compound represented by following General formula (2) is more preferable.

[Wherein R ³ represents a hydrogen atom or a methyl group, R ⁴ represents the same or different alkyl group having 4 or less carbon atoms, and R ⁵ represents a phenyl group or an alkyl group having 4 or less carbon atoms]

In the general formula (2), the alkyl group having 4 or less carbon atoms represented by R ⁴ and R ⁵ includes a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an i-butyl group, t -A butyl group etc. are mentioned.

  (C) As a silane compound, vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltripropoxysilane are preferable.

  Specific examples of the (c) silane compound include “KBM-1003 (vinyltrimethoxysilane)” and “KBE-1003 (vinyltriethoxysilane)” manufactured by Shin-Etsu Silicone.

  The (d) organic peroxide used in the resin composition will be described.

  The (d) organic peroxide used in the present invention is not particularly limited as long as it is a compound generally used in the grafting reaction of polyolefin. For example, benzoyl peroxide, dicumyl peroxide, di-t-butyl Peroxide, t-butyloxy-2-ethylhexanoate, cumene hydroperoxide, succinic peroxide, di (2-ethoxyethyl) peroxydicarbonate, (α, α'-bis-neodecanoyl peroxy) Diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneo Decanoate, t-butylperoxyneodecanoate, t-hexyl Ruperoxypivalate, t-butylperoxyneohexanoate, t-amylperoxy-2-ethylhexanoate, t-butylperoxypivalate, t-amylperoxypivalate, 1,1,3 3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy-2- Ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxyisopropylmonocarbonate, t -Butylperoxy 3,5,5-tri-methylhexanoate, t-butylperoxyla Rate, 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy 2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxy m-toluoylbenzoate, t-butylperoxybenzoate, bis-t-butylperoxy Isophthalate, 2,4,4-trimethylpentylperoxy-phenoxyacetate, di-t-butylperoxyhexahydroterephthalate, di-t-butylperoxyazelate, di-t-butylperoxy-trimethyladipate Can be mentioned. These organic peroxides may be used alone or in combination of two or more.

  Among these, an organic peroxide having a half-life of less than 6 minutes at the temperature (reaction temperature) when the components (a) to (d) or the components (a) to (e) are melt-mixed is preferable, and more preferable. Is an organic peroxide having a half-life of less than 1 minute at the reaction temperature. Specifically, benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyloxy-2-ethylhexanoate and the like are preferable.

  Specific examples of the organic peroxide (d) include “Nyper (registered trademark) FF”, “Perhexa (registered trademark) 25B”, and “Park Mill (registered trademark) D” manufactured by NOF. .

  In addition to the components (a) to (d), the resin composition is preferably obtained by further reacting (e) a rubber softener. (E) By using the rubber softener, the fluidity of the resin composition is improved, so that the fluidity of the cover composition is improved and the moldability of the cover is further improved. Moreover, the slab hardness and the rebound resilience of the cover composition can be adjusted by adjusting the blending amount of the rubber softener (e).

  The (e) rubber softener is not particularly limited, and examples thereof include paraffinic, naphthenic and aromatic mineral oil hydrocarbons; low molecular weight synthetic resin hydrocarbons such as polybutenes and polybutadienes. Etc. Among these, mineral oil-based hydrocarbons are preferable because cover molding from the cover composition is easy, and those having a weight average molecular weight of 300 to 2000, particularly 500 to 1500 are preferable.

  As a mineral oil rubber softener, a mixture of aromatic hydrocarbon, naphthene hydrocarbon and paraffin hydrocarbon is generally used. Usually, the mineral oil-based rubber softener is an aromatic oil whose aromatic hydrocarbon number is 30% by mass or more of the total carbon number, and the naphthenic hydrocarbon number of carbon is equal to the total carbon number. Those having 30% to 45% by mass are called naphthenic oils, and those having 50% by mass or more of paraffinic hydrocarbons in the total number of carbons are called paraffinic oils. As the rubber softener (e) used in the present invention, paraffinic oil is particularly preferable from the viewpoint of weather resistance and color tone.

  Specific examples of the above-mentioned (e) rubber softener are illustrated by trade names: “Diana (registered trademark) process oil PW90”, “Diana process oil PW32”, “Diana process oil PW150” manufactured by Idemitsu Kosan, Matsumura Oil "Barrel process oil P series" and the like.

  When the (e) rubber softener is used, the blending ratio of the hydrogenated product of (a) block copolymer, (b) olefin polymer and (e) rubber softener in the resin composition (total (When 100% by mass), (a) hydrogenated block copolymer / (b) olefin polymer / (e) rubber softener = 20% by mass to 80% by mass / 5% by mass to 50% The mass% is preferably 1% by mass to 40% by mass, and more preferably 40% by mass to 70% by mass / 10% by mass to 50% by mass / 5% by mass to 20% by mass.

  The compounding amount of the (c) silane compound in the resin composition is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the total amount of the component (a), the component (b) and the component (e). Preferably it is 0.2 mass part or more, More preferably, it is 0.5 mass part or more, 10 mass parts or less are preferable, More preferably, it is 5 mass parts or less, More preferably, it is 3 mass parts or less. If the blending amount of the (c) silane compound is 0.01 parts by mass or more, sufficient grafting and crosslinking degree can be obtained, so that the scuff resistance of the obtained cover is further improved, while 10 parts by mass or less. If so, it is suppressed that the melt viscosity of the cover composition becomes too high during cover molding, workability is good, and moldability is good.

  The blending amount of the organic peroxide (d) in the resin composition is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the total amount of the component (a), the component (b) and the component (e). More preferably, it is 0.02 parts by mass or more, more preferably 0.1 parts by mass or more, preferably 3 parts by mass or less, more preferably 2 parts by mass or less, still more preferably 1.5 parts by mass or less. If the blending amount of the (d) organic peroxide is 0.01 parts by mass or more, the grafting reaction proceeds sufficiently to easily obtain a desired three-dimensional crosslinking rate, while if it is 3 parts by mass or less, organic An unintended cross-linking reaction (peroxide cross-linking) due to peroxide does not proceed, the occurrence of scorch phenomenon, a decrease in surface smoothness, an increase in viscosity, and the like are suppressed, and the cover moldability is good.

  The resin composition is obtained by reacting the components (a) to (d) or the components (a) to (e) described above, and the preparation method thereof will be described later.

  The melt flow rate (230 ° C., 5 kg load) of the resin composition is preferably 10 g / 10 min or more, more preferably 15 g / 10 min or more, still more preferably 20 g / 10 min or more, and preferably 60 g / 10 min or less. Preferably it is 55 g / 10min or less, More preferably, it is 50 g / 10min or less. When the melt flow rate of the resin composition is within the above range, the fluidity of the cover composition is improved and the thin cover can be easily molded.

  Next, the cover composition used in the present invention will be described.

  The cover composition is preferably obtained by further adding (f) a silanol condensation catalyst composition to the resin composition.

  The (f) silanol condensation catalyst composition is a mixture of a silanol condensation catalyst and a thermoplastic resin. When the silanol condensation catalyst is added directly in the same manner as other components, a cross-linking reaction is likely to occur locally in the molded cover, resulting in a decrease in molding appearance, a decrease in fluidity of the cover composition, and cover molding. Problems such as local accumulation in the machine and acceleration of corrosion of the device may occur. Therefore, it is preferable that the silanol condensation catalyst is mixed with a thermoplastic resin in advance to prepare a masterbatch, and this masterbatch and other components are mixed to improve the handleability.

  Examples of the silanol condensation catalyst used in the (f) silanol condensation catalyst composition include carboxylic acid compounds such as acetic acid, stearic acid and maleic acid, compounds having a sulfonic acid group such as dodecylbenzenesulfonic acid and toluenesulfonic acid, Organic base compounds such as dibutylamine, hexylamine and pyridine; inorganic acids such as sulfuric acid and hydrochloric acid; dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, stannous acetate, stannous caprylate, etc. Organic tin compounds, organic titanium compounds such as tetrabutyl titanate, tetranonyl titanate, organic zinc compounds, organic iron compounds, organic lead compounds such as lead naphthenate, organic cobalt compounds such as cobalt naphthenate, etc. Metal compounds; Etc., and the like. These silanol condensation catalysts may be used alone or in combination of two or more. Among these, a compound having a sulfonic acid group and an organic tin compound are preferable, and dodecylbenzenesulfonic acid is particularly preferable.

  What is necessary is just to use what was illustrated as said (a) component or (b) component as a thermoplastic resin which comprises the said (f) silanol condensation catalyst composition. The thermoplastic resin constituting the (f) silanol condensation catalyst composition is preferably polyethylene.

  (F) The content of the silanol condensation catalyst in the silanol condensation catalyst composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and further preferably 0.3% by mass or more. It is preferably at most 5% by mass, more preferably at most 5% by mass, even more preferably at most 3% by mass.

  The amount of the (f) silanol condensation catalyst composition in the cover composition is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, with respect to 100 parts by mass of the resin composition. More preferably, it is 1 mass part or more, 10 mass parts or less are preferable, More preferably, it is 8 mass parts or less, More preferably, it is 5 mass parts or less. If the blending amount of the (f) silanol condensation catalyst composition is 0.2 parts by mass or more, the progress of the crosslinking reaction can be accelerated, and workability is improved. Early cross-linking does not occur during molding, and the occurrence of the scorch phenomenon can be suppressed.

  The cover composition used in the present invention is not particularly limited as long as it contains the above-described resin composition as a resin component. The total content of the resin composition and the component (f) in the resin component constituting the cover composition is preferably 50% by mass or more, and more preferably 70% by mass or more. By setting the total content of the resin composition and the component (f) in the resin component constituting the cover composition to 50% by mass or more, the fluidity of the cover composition is improved and the resistance is improved. The effect of improving scratch resistance and resilience is further increased. It is particularly preferable that the cover composition contains only the resin composition and (f) a silanol condensation catalyst composition as resin components.

  The cover composition can contain other resin components as a resin component as long as the effects of the present invention are not impaired.

  As said other resin component, a polyurethane resin, an ionomer resin, a thermoplastic elastomer etc. can be mentioned, for example. Specific examples of the polyurethane resin include “Elastolan (registered trademark)” commercially available from BASF Japan. Specific examples of the ionomer resin include “Himiran (registered trademark)” commercially available from Mitsui DuPont Polychemical Co., Ltd. Specific examples of the thermoplastic elastomer include, for example, a thermoplastic polyamide elastomer commercially available from Arkema Co., Ltd. under the trade name “Pebax (registered trademark)” (for example, “Pebax 2533”), Toray DuPont Co., Ltd. Commercially available under the trade name “Hytrel® (for example,“ Hytrel 3548 ”,“ Hytrel 4047 ”)” or the product name “Primalloy® (for example“ Primalloy A1500 ”) from Mitsubishi Chemical Corporation. And thermoplastic polystyrene elastomers commercially available from Mitsubishi Chemical Corporation under the trade name “Lavalon (registered trademark)”.

  In addition to the resin component described above, the cover composition used in the present invention is a pigment component such as a white pigment (titanium oxide), a blue pigment, or a red pigment; a specific gravity adjusting agent such as zinc oxide, calcium carbonate, or barium sulfate; A property modifier, a dispersant, an anti-aging agent, an ultraviolet absorber, a light stabilizer, a fluorescent material, a fluorescent brightening agent, and the like may be contained as long as the performance of the cover is not impaired.

  The content of the pigment component is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 100 parts by mass of the resin component constituting the cover. Is desirably 8 parts by mass or less. By making the content of the pigment component 0.5 parts by mass or more, the cover can be concealed. Moreover, it is because durability of the cover obtained may fall when content of a pigment component exceeds 10 mass parts. Examples of the fluidity modifier include silicon elastomer. Specific examples of the silicone elastomer include, for example, a copolymer of polydimethylsiloxane and urea commercially available from Asahi Kasei Wacker Silicone Co., Ltd. under the trade name “GENIOMER (registered trademark)”.

  The impact resilience of the cover composition is preferably 40% or more, more preferably 42% or more, still more preferably 45% or more, preferably 70% or less, more preferably 68% or less, and still more preferably 66. % Or less. If the impact resilience of the cover composition is within the above range, the resilience of the resulting golf ball can be improved.

  The slab hardness of the cover composition is preferably a Shore A hardness of 75 or more, more preferably 76 or more, still more preferably 77 or more, preferably 98 or less, more preferably 95 or less, and still more preferably 90 or less. It is. When the slab hardness of the cover composition is within the above range in terms of Shore A hardness, the feeling of the obtained golf ball and the spin rate at the approach shot increase, and the controllability improves.

  The bending elastic modulus of the cover composition is preferably 10 MPa or more, more preferably 11 MPa or more, further preferably 12 MPa or more, preferably 300 MPa or less, more preferably 250 MPa or less, and further preferably 200 MPa or less. When the bending elastic modulus of the cover composition is within the above range, the spin performance upon shot by a driver is good.

  The three-dimensional crosslinking rate of the cover composition is preferably 15% by mass or more, more preferably 16% by mass or more, still more preferably 17% by mass or more, and preferably 50% by mass or less, more preferably 49% by mass. Hereinafter, it is more preferably 48% by mass or less. When the three-dimensional crosslinking rate of the cover composition is within the above range, the scratch resistance of the resulting golf ball is improved.

  The rebound resilience, flexural modulus, and tensile fracture strength of the cover composition are values measured by molding the cover composition into a sheet shape, and are measured by a measurement method described later. The three-dimensional crosslinking rate of the cover composition can be determined from the insoluble content of the formed cover by refluxing xylene, and the measurement method will be described later.

  Next, the manufacturing method of the golf ball of the present invention will be described.

  The method for producing a golf ball of the present invention comprises: (a) a hydrogenated block copolymer having at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block; A step of preparing a resin composition by reacting a polymer, (c) a silane compound represented by the following general formula (1), and (d) an organic peroxide; a composition for a cover using the obtained resin composition Preparing a product and molding a cover from the cover composition.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]

  In the present invention, in the step of preparing the resin composition, (a) a hydrogenated block copolymer, (b) an olefin copolymer, (c) a silane compound, and (d) an organic peroxide are reacted. By doing so, the component (c) is graft-polymerized to the component (a) and the component (b), and a hydrolyzable group is introduced into the component (a) and the component (b). Next, in the step of molding the cover described later, the hydrolyzable group introduced into the component (a) and the hydrolyzable group introduced into the component (b) are hydrolyzed / crosslinked, so that A three-dimensional crosslinked structure is formed, and the resilience and scratch resistance of the cover can be improved.

  The process for preparing the resin composition will be described.

  In the step of preparing the resin composition, the method of reacting the components (a) to (d) is not particularly limited, and examples thereof include a melting method, a solution method, and a suspension polymerization method. A melt kneading method is preferred. For the melt-kneading method, a normal melt-kneader, for example, a single-screw extruder, a twin-screw extruder, a Banbury mixer, a mixing roll, a kneader blender, a Brabender plastograph, a horizontal twin-screw reactor, or the like may be used. it can. Among these, a twin screw extruder is industrially suitable.

  When the resin composition is prepared by the melt kneading method, the mixing temperature is preferably 100 ° C or higher, more preferably 120 ° C or higher, preferably 400 ° C or lower, more preferably 250 ° C or lower. If the mixing temperature is too high, the resin component may be severely deteriorated.

  Moreover, as an aspect of melt-kneading each component, for example, when melt-kneading using an extruder, (a) to (d) an aspect in which all the components are added together and mixed; (a) to (c) component A mode in which the component (d) is added and mixed using a side feeder or the like after first charging the component; after the components (a), (b) and (d) are first charged, the side feeder or the like is used. (C) A mode in which the component is added and mixed; a mode in which the components (a), (c) and (d) are first added and then the component (b) is added and mixed using a side feeder or the like; In order to obtain the desired physical properties according to the blending ratio of each component, a generally known mode may be adopted.

  In addition, in the process of preparing a resin composition, when melt-kneading each component, the (a)-(d) component must be finally mix | blended by one mixing. For example, if only the components (c) and (d) are melt-kneaded and the mixture is temporarily stored and then mixed with the components (a) and (b), the effects of the present invention cannot be obtained. That is, in the present invention, in the step of preparing the resin composition, by reacting the components (a) to (d) by a single mixing, hydrolyzable groups are present in the components (a) and (b). It is introduced uniformly. As a result, a three-dimensional cross-linking structure is uniformly formed in the molded cover.

  In the golf ball manufacturing method of the present invention, in the step of preparing the resin composition, it is preferable to further add (e) a rubber softener in addition to the components (a) to (d). Preparation of the resin composition in the case of using the component (e) may be performed in the same manner as the method of melt-kneading the components (a) to (d).

  Next, a process for preparing a cover composition using the obtained resin composition and molding a cover from the cover composition will be described.

  Examples of a method for preparing a cover composition using the resin composition include an embodiment in which the resin composition and a cover additive such as titanium oxide are mixed. The method of mixing the resin composition and the cover additive such as titanium oxide is not particularly limited. For example, it is preferable to use a mixer that can blend pellet-shaped raw materials, and more preferably to use a tumbler mixer. preferable.

  In the golf ball manufacturing method of the present invention, in the step of molding the cover, it is preferable to prepare a cover composition by further adding (f) a silanol condensation catalyst composition to the resin composition. When the component (f) is used, as a method for preparing the cover composition, for example, (I) a resin composition and a cover additive such as titanium oxide are mixed and pelletized, and then the pellet ( f) A mode in which the component is mixed; (II) A mode in which the component (f) and a cover additive such as titanium oxide are mixed and pelletized, and then the pellet and the resin composition are mixed; (III) Resin Examples include an embodiment in which the composition, the component (f), and a cover additive such as titanium oxide are mixed at the same time.

  In the method for producing a golf ball of the present invention, an aspect of molding the cover using the cover composition is not particularly limited, but an aspect in which the cover composition is directly injection-molded on the core; An embodiment in which a shell-like shell is formed, and the core is covered with a plurality of shells and compression-molded (preferably, a hollow shell-shaped half shell is formed from the cover composition, and the core is covered with two half-shells. And an aspect of compression molding). In the golf ball manufacturing method of the present invention, an embodiment in which the cover composition is directly injection-molded on the core is preferable. In addition, when the cover composition is directly injection-molded on the core, for example, a pellet of the cover composition may be prepared using an extruder, and then the injection molding may be performed using the pellet. A cover material may be mixed to prepare a cover composition, which may be directly injection molded without being pelletized.

  When forming a cover by direct injection molding of the cover composition onto the core, the upper and lower molds for cover molding have a hemispherical cavity, with pimples, and a part of the pimples can be advanced and retracted It is preferable to use the one that also serves as The cover can be molded by injection molding by protruding the hold pin, inserting the core and holding it, and then injecting the heat-melted composition for the cover and cooling, for example, The cover composition heated to 200 ° C. or more and 250 ° C. or less is injected into the mold clamped at a pressure of 980 Kpa or more and 1,500 KPa or less in 0.5 seconds or more and 5 seconds or less, and 10 seconds or more and 60 seconds or less. This is done by cooling and opening the mold.

  In the cover composition used in the present invention, the hydrolyzable group introduced into the components (a) and (b) undergoes a hydrolysis / crosslinking reaction to form a three-dimensional crosslinked structure in the cover. Here, the molding of the cover is performed in a sealed environment of 100 ° C. or more as in the case of injection molding, and the cover composition is isolated from moisture, and the hydrolysis / condensation reaction of the hydrolyzable group does not proceed. Therefore, the moldability of the cover is good.

  In addition, after the cover is formed, the hydrolysis / condensation reaction of the hydrolyzable group usually proceeds automatically in a water atmosphere at a temperature of 5 ° C. or higher and a humidity of 20% or higher. For example, when the cover composition contains (f) a silanol condensation catalyst composition, the hydrolysis / crosslinking reaction is completed in about 48 hours to 72 hours. Therefore, a three-dimensional crosslinked structure can be formed in the cover without performing a special crosslinking treatment. In addition, when a hydrolyzable group such as an alkoxysilane group undergoes hydrolysis and condensation reaction, a trace amount of alcohol is generated, but the cover formed from the cover composition has a very high gas permeability, Since the generated alcohol is immediately released out of the system, the generated alcohol does not cause defects in the cover.

  Here, in the golf ball manufacturing method of the present invention, a crosslinking treatment may be performed as necessary. The crosslinking treatment applied to the molded cover is not particularly limited, and the golf ball formed with the cover may be exposed to a water atmosphere. By performing the crosslinking treatment, hydrolysis reaction and condensation reaction of the alkoxysilane group introduced into the component (a) and the component (b) can be promoted. Examples of the crosslinking treatment include a method of immersing in water at 60 ° C. to 80 ° C., a method of exposing to a humid atmosphere of 60% to 80 ° C. and a humidity of 80% or more, a method of spraying steam, and a method of showering with hot water. Can be mentioned.

  The thickness of the cover of the golf ball of the present invention is not particularly limited, but is preferably 0.3 mm or more, more preferably 0.5 mm or more, and further preferably 0.7 mm or more. This is because if the cover is too thin, the scratch resistance tends to decrease. Moreover, it is preferable that the thickness of a cover is 2.5 mm or less, More preferably, it is 2.3 mm or less, More preferably, it is 2.1 mm or less. If the cover is too thick, the resilience may decrease.

  Further, when molding the cover, a depression called dimple is usually formed on the surface. Further, it is preferable that the golf ball main body with the cover formed is taken out from the mold and subjected to surface treatment such as deburring, washing, and sand blasting as necessary. Moreover, a coating film and a mark can also be formed if desired. The film thickness of the coating film is not particularly limited, but is preferably 5 μm or more, more preferably 7 μm or more and 25 μm or less, and more preferably 18 μm or less. This is because if the film thickness is less than 5 μm, the coating film tends to wear and disappear due to continuous use, and if the film thickness exceeds 25 μm, the dimple effect decreases and the flight performance of the golf ball decreases.

  Next, a preferred embodiment of the core of the golf ball of the present invention will be described.

  Examples of the structure of the core of the golf ball of the present invention include a single-layer core, a core composed of a center and a single-layer intermediate layer covering the center, and a plurality of or multiple intermediate layers covering the center and the center. And a core composed of The core shape is preferably spherical. When the core shape is not spherical, the thickness of the cover is not uniform. As a result, a part in which the cover performance is partially reduced occurs. On the other hand, the shape of the center is generally spherical, but a ridge may be provided so as to divide the surface of the spherical center, for example, the ridge so as to divide the surface of the spherical center equally. May be provided. As an aspect which provides the said protrusion, the aspect which provides a protrusion integrally with a center on the surface of a spherical center, the aspect which provides the intermediate | middle layer of a protrusion on the surface of a spherical center, etc. can be mentioned, for example.

  For example, when the spherical center is regarded as the earth, the ridge is preferably provided along an equator and an arbitrary meridian that equally divides the surface of the spherical center. For example, when the spherical center surface is divided into 8 parts, 90 degrees east longitude, 90 degrees west longitude, and east longitude (west longitude) with reference to the equator, an arbitrary meridian (longitude 0 degrees), and the meridian of such longitude 0 degrees It may be provided along the meridian of 180 degrees. When providing the ridge, the concave portion partitioned by the ridge is filled with a plurality of intermediate layers or a single intermediate layer covering each of the concave portions, and the core shape is made spherical. It is preferable to do so. The cross-sectional shape of the protrusion is not particularly limited, and examples thereof include an arc shape or a substantially arc shape (for example, a shape in which notched portions are provided at portions intersecting or orthogonal to each other).

  For the core or center of the golf ball of the present invention, a conventionally known rubber composition (hereinafter may be simply referred to as “core rubber composition”) may be employed. A rubber composition containing an agent, a co-crosslinking agent, and a filler can be molded by hot pressing. The shape of the core is preferably spherical. When the core shape is not spherical, the thickness of the cover is not uniform. As a result, a part in which the cover performance is partially reduced occurs.

  As the base rubber, natural rubber and / or synthetic rubber can be used. For example, polybutadiene rubber, natural rubber, polyisoprene rubber, styrene polybutadiene rubber, ethylene-propylene-diene rubber (EPDM) and the like can be used. Among these, it is particularly preferable to use a high-cis polybutadiene having a cis bond advantageous for repulsion of 40% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

  The said crosslinking initiator is mix | blended in order to bridge | crosslink a base rubber component. As the crosslinking initiator, an organic peroxide is suitable. Specifically, dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, Examples thereof include organic peroxides such as di-t-butyl peroxide, among which dicumyl peroxide is preferably used. The amount of the crosslinking initiator is preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 3 parts by mass or less, more preferably 100 parts by mass of the base rubber. 2 parts by mass or less. If it is less than 0.2 parts by mass, the core tends to be too soft and the resilience tends to decrease. If it exceeds 3 parts by mass, it is necessary to increase the amount of co-crosslinking agent used in order to obtain an appropriate hardness. There is a lack of resilience.

  The co-crosslinking agent is not particularly limited as long as it has a function of crosslinking rubber molecules by graft polymerization to a base rubber molecular chain. For example, α, β- having 3 to 8 carbon atoms. Unsaturated carboxylic acid or its metal salt can be used, Preferably, acrylic acid, methacrylic acid, or these metal salts can be mentioned. Examples of the metal constituting the metal salt include zinc, magnesium, calcium, aluminum, sodium and the like, and zinc is preferably used because resilience increases. The amount of the co-crosslinking agent used is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, relative to 100 parts by mass of the base rubber. It is desirable that When the amount of the co-crosslinking agent used is less than 10 parts by mass, the amount of the crosslinking initiator must be increased in order to obtain an appropriate hardness, and the resilience tends to decrease. On the other hand, when the usage-amount of a co-crosslinking agent exceeds 50 mass parts, a core may become hard too much and there exists a possibility that a shot feeling may fall.

  The filler contained in the core rubber composition is mainly blended as a specific gravity adjusting agent for adjusting the specific gravity of the golf ball obtained as a final product to a range of 1.0 to 1.5. What is necessary is just to mix | blend as needed. Examples of the filler include inorganic fillers such as zinc oxide, barium sulfate, calcium carbonate, magnesium oxide, tungsten powder, and molybdenum powder. The blending amount of the filler is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, and preferably 50 parts by mass or less, more preferably 35 parts by mass or less with respect to 100 parts by mass of the base rubber. It is desirable that If the blending amount of the filler is less than 2 parts by mass, it is difficult to adjust the weight, and if it exceeds 50 parts by mass, the weight fraction of the rubber component tends to decrease and the resilience tends to decrease.

  In addition to the base rubber, the crosslinking initiator, the co-crosslinking agent, and the filler, an organic sulfur compound, an antiaging agent, a peptizer, and the like can be appropriately added to the core rubber composition.

  As the organic sulfur compound, diphenyl disulfides can be preferably used. Examples of the diphenyl disulfides include diphenyl disulfide; bis (4-chlorophenyl) disulfide, bis (3-chlorophenyl) disulfide, bis (4-bromophenyl) disulfide, bis (3-bromophenyl) disulfide, bis (4- Mono-substituted products such as fluorophenyl) disulfide, bis (4-iodophenyl) disulfide, bis (4-cyanophenyl) disulfide; bis (2,5-dichlorophenyl) disulfide, bis (3,5-dichlorophenyl) disulfide, bis ( 2,6-dichlorophenyl) disulfide, bis (2,5-dibromophenyl) disulfide, bis (3,5-dibromophenyl) disulfide, bis (2-chloro-5-bromophenyl) disulfide, bis (2-cyano Disubstituted compounds such as 5-bromophenyl) disulfide; trisubstituted compounds such as bis (2,4,6-trichlorophenyl) disulfide and bis (2-cyano-4-chloro-6-bromophenyl) disulfide; bis (2 , 3,5,6-tetrachlorophenyl) disulfide and the like; bis (2,3,4,5,6-pentachlorophenyl) disulfide, bis (2,3,4,5,6-pentabromophenyl) Examples include penta-substituted products such as disulfide. These diphenyl disulfides have some influence on the vulcanized state of the rubber vulcanizate and can improve the resilience. Among these, it is preferable to use diphenyl disulfide and bis (pentabromophenyl) disulfide from the viewpoint that a highly repulsive golf ball can be obtained. The compounding amount of the organic sulfur compound is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more and preferably 5.0 parts by mass or less with respect to 100 parts by mass of the base rubber. More preferably, it is 3.0 parts by mass or less.

  The blending amount of the anti-aging agent is preferably 0.1 parts by mass or more and 1 part by mass or less with respect to 100 parts by mass of the base rubber. Moreover, it is preferable that the compounding quantity of a peptizer is 0.1 to 5 mass parts with respect to 100 mass parts of base rubber.

  The hot-press molding conditions for the core rubber composition may be appropriately set according to the rubber composition, but are usually heated at 130 to 200 ° C. for 10 to 60 minutes, or at 130 to 150 ° C. for 20 to 40 minutes. After heating, it is preferable to heat at 160 to 180 ° C. for 2 to 5 minutes.

  When the golf ball of the present invention is a three-piece golf ball or a multi-piece golf ball, as the intermediate layer, for example, a cured product of a rubber composition, a conventionally known ionomer resin, a product name “Arkema Co., Ltd.” Thermoplastic polyamide elastomer commercially available from Pebax (registered trademark) (for example, “Pebucks 2533”), trade names “Hytrel” (for example, “Hytrel 3548”, “Hytrel 4047” from Toray DuPont Co., Ltd.) ”)”, A thermoplastic polyurethane elastomer commercially available from BASF Japan under the trade name “Elastolan (registered trademark)” (for example, “Elastolan XNY97A”), Mitsubishi Chemical Corporation ) Under the trade name "Lavalon (registered trademark)" Thermoplastic polystyrene elastomers, and the like that. As the ionomer resin, in particular, an ionomer resin obtained by neutralizing at least a part of a carboxyl group in a copolymer of ethylene and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms with a metal ion, ethylene and carbon number What neutralized at least one part of the carboxyl group in the terpolymer of 3-8 alpha, beta-unsaturated carboxylic acid and alpha, beta-unsaturated carboxylic acid ester with a metal ion, or these Can be mentioned.

  Specific examples of the ionomer resin are illustrated by trade names, such as “Himilan (registered trademark)” (for example, Himilan 1555 (Na), Himilan 1557 (Zn), Himilan, which is commercially available from Mitsui DuPont Polychemical Co., Ltd. 1605 (Na), HiMilan 1706 (Zn), HiMilan 1707 (Na), HiMilan AM7311 (Mg), and the like. Examples of the terpolymer ionomer resins include HiMilan 1856 (Na) and HiMilan 1855 (Zn). ".

  Further, ionomer resins commercially available from DuPont include “Surlyn (registered trademark)” (for example, Surlyn 8945 (Na), Surlyn 9945 (Zn), Surlyn 8140 (Na), Surlyn 8150 (Na), Surlyn 9120 (Zn), Surlyn 9150 (Zn), Surlyn 6910 (Mg), Surlyn 6120 (Mg), Surlyn 7930 (Li), Surlyn 7940 (Li), Surlyn AD8546 (Li) and the like, and terpolymers Examples of the ionomer resin include Surlyn 8120 (Na), Surlyn 8320 (Na), Surlyn 9320 (Zn), Surlyn 6320 (Mg)), “HPF 1000 (Mg), HPF 2000 (Mg)”.

  Examples of ionomer resins commercially available from ExxonMobil Chemical Co., Ltd. include “Iotek (registered trademark)” (for example, Iotech 8000 (Na), Iotech 8030 (Na), Iotech 7010 (Zn), Iotech 7030 ( Zn) and the like, and examples of the ternary copolymer ionomer resin include Iotech 7510 (Zn) and Iotech 7520 (Zn)).

  Note that Na, Zn, Li, Mg, and the like described in parentheses after the trade name of the ionomer resin indicate the metal species of these neutralized metal ions. The intermediate layer may further contain a specific gravity adjusting agent such as barium sulfate or tungsten, an anti-aging agent, or a pigment.

  When the golf ball of the present invention is a three-piece golf ball or a multi-piece golf ball, the center diameter is preferably 30 mm or more, more preferably 32 mm or more, and preferably 41 mm or less, more preferably 40.5 mm or less. It is desirable. When the diameter of the center is smaller than 30 mm, the intermediate layer or the cover needs to be thicker than a desired thickness, and as a result, the resilience may be lowered. On the other hand, when the diameter of the center exceeds 41 mm, it is necessary to make the intermediate layer or cover thinner than a desired thickness, and the function of the intermediate layer or cover layer is not sufficiently exhibited.

  The core used in the golf ball of the present invention preferably has a diameter of 39 mm or more, more preferably 39.5 mm or more, still more preferably 40.8 mm or more, preferably 42.2 mm or less, more preferably 42 mm or less, even more preferably. Is preferably 41.8 mm or less. If the core diameter is less than the above lower limit, the cover will be too thick and the rebound will be reduced.On the other hand, if the core diameter exceeds the upper limit, the cover will be too thick. This is because molding becomes difficult.

  When the core has a diameter of 39 mm to 42.2 mm, the amount of compressive deformation (the amount by which the core shrinks in the compression direction) from when the initial load 98 N is applied to when the final load 1275 N is applied is 2.50 mm or more. It is preferably 2.60 mm or more, 3.20 mm or less, and more preferably 3.10 mm or less. When the amount of compressive deformation is less than 2.50 mm, the feel at impact is hard and worse, and when it exceeds 3.20 mm, the resilience may be lowered.

  It is also a preferred aspect to use a core having a hardness difference between the center and the surface, and the difference between the surface hardness and the center hardness according to JIS-C hardness is preferably 10 or more, more preferably 12 or more, 40 or less is preferable, 35 or less is more preferable, and 30 or less is still more preferable. If the hardness difference is larger than 40, the durability may be lowered. If the hardness difference is smaller than 10, the shot feeling may be hard and the impact may be increased. The surface hardness of the core is JIS-C hardness, preferably 65 or more, more preferably 70 or more, still more preferably 72 or more, and preferably 85 or less. If the surface hardness of the core is less than 65 in terms of JIS-C hardness, the core becomes too soft and the resilience is lowered, which may reduce the flight distance. On the other hand, if the core surface hardness is greater than 85, the core may become too hard and the feel at impact may deteriorate. The center hardness of the core is JIS-C hardness, preferably 45 or more, more preferably 50 or more, preferably 70 or less, more preferably 65 or less. If the core center hardness is less than 45, the core becomes too soft and the durability may be reduced. If the core center hardness is greater than 70, the core may become too hard and the feel at impact may deteriorate. The hardness difference of the core can be provided by appropriately selecting the thermoforming conditions for the core.

  The structure of the golf ball of the present invention is not particularly limited as long as it has a core and a cover, and a two-piece golf ball having a single-layer core and a cover covering the core; the center and the center are covered. A three-piece golf ball having a core composed of a single intermediate layer and a cover covering the core; a core composed of a center and a plurality of or multiple intermediate layers covering the center; and a cover covering the core A multi-piece golf ball having a thread-wound golf ball having a thread-wound core and a cover may be used. This is because the present invention can be preferably applied in any case.

  When the golf ball of the present invention is a thread wound golf ball, a thread wound core may be used as the core. In such a case, as the thread wound core, for example, a thread core composed of a center formed by curing the core rubber composition described above and a thread rubber layer formed by winding the thread rubber around the center in a stretched state is used. do it. The thread rubber wound on the center may be the same as that conventionally used for the thread wound layer of a thread wound golf ball, for example, natural rubber or natural rubber and synthetic polyisoprene with sulfur, You may use what was obtained by vulcanizing the rubber composition which mix | blended the vulcanization adjuvant, the vulcanization accelerator, the anti-aging agent, etc. The thread rubber is stretched about 10 times on the center and wound to form a thread wound core.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Evaluation methods]
(1) Core hardness (JIS-C)
Using a spring type hardness tester C type defined in JIS-K 6301, the JIS-C hardness measured at the surface of the core was defined as the surface hardness of the core, the core was cut into a hemisphere, and measured at the center of the cut surface. The JIS-C hardness was defined as the center hardness of the core.

(2) Compression deformation (mm)
The amount of deformation in the compression direction (the amount by which the core or golf ball shrinks in the compression direction) from when the initial load 98N was applied to the core or golf ball to when the final load 1275N was applied was measured.

(3) Rebound resilience Using the cover composition, a sheet having a thickness of about 2 mm was produced by hot press molding, and six sheets were cut from the sheet into a circular shape having a diameter of 28 mm. A cylindrical specimen having a diameter of about 12 mm and a diameter of 28 mm was produced. A Rüpke-type rebound resilience test (test temperature and humidity 23 ° C., 50 RH%) was performed on this test piece. The test piece was prepared and tested in accordance with JIS K6255.

(4) Slab hardness (Shore A hardness)
Using the cover composition, a sheet having a thickness of about 2 mm was produced by hot press molding and stored at 23 ° C. for 2 weeks. An automatic rubber hardness tester P1 type manufactured by Kobunshi Keiki Co., Ltd. equipped with a spring type hardness tester Shore A type as defined in ASTM-D2240 in a state where three or more sheets are stacked so as not to affect the measurement substrate or the like. It measured using.

(5) Flexural modulus Using the cover composition, a test piece having a length of 80.0 ± 2 mm, a width of 10.0 ± 0.2 mm, and a thickness of 4.0 ± 0.2 mm was produced by injection molding. Stored at 23 ° C. for 2 weeks. The bending elastic modulus of this sheet was measured according to ISO178. The measurement was performed at a temperature of 23 ° C. and a humidity of 50% RH.

(6) Three-dimensional crosslinking rate Using the cover composition, a test piece of 1 mm square or less was produced in the same manner as the cover molding conditions, and the three-dimensional crosslinking rate was measured. The measurement of the three-dimensional crosslinking rate is based on ISO 10147-1994, and the sample was continuously extracted with a Soxhlet extractor using xylene as the solvent at the boiling temperature of xylene for 10 hours. It calculated using the following formula | equation using the weight.

(7) Melt flow rate (MFR) of resin composition
The MFR of the resin compositions obtained in the examples was measured according to JIS K7210 using a flow tester (manufactured by Shimadzu Corporation, Shimadzu flow tester CFT-100C). The measurement conditions were golf ball No. 4 was performed under the conditions of a measurement temperature of 230 ° C. and a load of 2.16 kg, and the other conditions were performed under the conditions of a measurement temperature of 230 ° C. and a load of 5 kg.

(8) Scratch resistance A golf club laboratory swing robot M / C is attached with a sand wedge (SRI Sports, Shaft S), and hits two locations of the ball once at a head speed of 36 m / sec. Observed and evaluated in 4 stages.
Evaluation criteria of scratch resistance ◎: There is no scratch on the surface of the golf ball.
○: Slight scratches remain on the surface of the golf ball, but are hardly noticed.
Δ: The surface of the golf ball is clearly scratched and slightly fuzzy.
X: The surface of the golf ball is considerably shaved and fuzz is conspicuous.

(9) Restitution coefficient Each golf ball was impacted with 198.4 g of a metal cylinder at a speed of 40 m / sec, and the speed of the cylinder and the golf ball before and after the collision was measured. The coefficient of restitution of the ball was calculated. The measurement was performed 12 pieces for each golf ball, and the average value was used as the coefficient of restitution of each golf ball. The coefficient of restitution is the golf ball no. The coefficient of restitution of 6 is assumed to be 100.0, and is shown as an indexed value.

(10) Approach performance A sand wedge (SRIXON I-302, manufactured by SRI Sports Co., Ltd.) is attached to a swing robot M / C manufactured by Golf Laboratory, and a golf ball is hit at a head speed of 21 m / sec. Spin speed (rpm) was measured by taking continuous photographs. The measurement was performed 10 times for each golf ball, and the average value was defined as the spin speed (rpm).

[Production of golf balls]
(1) Production of core Production of core A The core composition having the composition shown in Table 1 was kneaded and heated and pressed at 160 ° C. for 13 minutes in an upper and lower mold having hemispherical cavities to obtain a diameter of 40.0 mm. Core A was obtained.

Preparation of Core B A rubber center composition having the composition shown in Table 1 was kneaded and heated and pressed at 170 ° C. for 15 minutes in an upper and lower mold having hemispherical cavities to obtain a spherical center having a diameter of 39.8 mm. . The intermediate layer material having the composition shown in Table 1 was mixed by a twin-screw kneading type extruder to prepare a pellet-shaped intermediate layer composition. Extrusion was performed with a screw diameter of 45 mm, a screw speed of 200 rpm, and a screw L / D = 35. The blend was heated to 150-230 ° C. at the die position of the extruder. The obtained intermediate layer composition is injection-molded on the center obtained as described above, and has a center B and an intermediate layer (thickness 1.0 mm) covering the center. Was made.

Polybutadiene rubber: “BR730 (high cis polybutadiene)” manufactured by JSR Corporation
Zinc oxide: Toho Zinc Co., Ltd., “Ginren (registered trademark) R”
Zinc acrylate: “ZNDA-90S” manufactured by Nippon Distillery
Barium sulfate: manufactured by Sakai Chemicals, "Barium sulfate BD"
Diphenyl disulfide: Sumitomo Seika's dicumyl peroxide: NOF "Park Mill (registered trademark) D"
High Milan 1605: Sodium ion neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd. High Milan AM7329: Zinc ion neutralized ethylene-methacrylic acid copolymer ionomer resin manufactured by Mitsui DuPont Polychemical

(2) Preparation of resin composition The components (a) and (e) shown in Table 2 were stirred for 5 minutes with a Henschel mixer, and then the components (b), (c) and (d) were added. Further, the blended product stirred for 1 minute was kneaded and reacted at a cylinder temperature of 200 ° C. and a discharge rate of 30 kg / hr using a twin-screw kneader (screw diameter: 30 mm, screw rotation speed: 200 rpm, L / D = 52). Thus, pellets of the resin composition were prepared. The final resin temperature was 210 ° C to 240 ° C.

(3) Preparation of cover composition Pellet of the obtained resin composition, (f) silanol condensation catalyst composition, and cover additive (titanium oxide) were tumbler type so as to have the composition shown in Table 2. A cover composition was prepared by dry blending using a mixer.

(4) Production of Golf Ball Body A cover was formed by injection-molding the obtained cover composition on the spherical core to produce a golf ball. The upper and lower molds for molding have hemispherical cavities, are provided with pimples, and also serve as hold pins in which a part of the pimples can advance and retreat. The hold pin is protruded, the core is inserted and then held, and a resin heated to 210 ° C. is injected into a mold clamped at a pressure of 80 tons in 0.3 seconds, cooled for 30 seconds, and the mold is opened to open a golf ball Was taken out. The obtained golf ball is stored for 48 hours to 72 hours in an atmosphere with a humidity of 20% or more, and then the surface of the golf ball body is sandblasted and marked, and then a clear paint is applied to the oven at 40 ° C. The paint was dried to obtain a golf ball having a diameter of 42.8 mm and a mass of 45.4 g.

Hydrogenated product of block copolymer A: Hydrogenated product of styrene-butadiene-styrene block copolymer (weight average molecular weight 80,000, styrene content 32% by mass)
Block copolymer hydrogenated product B: Hydrogenated product of styrene-isoprene-styrene block copolymer (weight average molecular weight 80,000, styrene content 60 mass%)
Olefin-based polymer A: Polypropylene (melt flow rate (MFR) 1 g / 10 min (230 ° C., 2.16 kg load), flexural modulus 1300 MPa)
Olefin polymer B: ethylene copolymer (density 0.89 g / cm ³ )
Rubber softener: “Diana (registered trademark) Process Oil PW90” manufactured by Idemitsu Kosan
Ethylenically unsaturated silane compound: “KBM-1003 (vinyltrimethoxysilane)” manufactured by Shin-Etsu Silicone
Organic peroxide: NOF "NIPA (registered trademark) FF"
Silanol condensation catalyst composition: Polyethylene resin in which dodecylbenzenesulfonic acid is dispersed (dodecylbenzenesulfonic acid content: 1.0 mass%)
Thermoplastic polyurethane: “Elastollan (registered trademark) ET885” manufactured by BASF
Divinylbenzene: Wako Pure Chemical Industries

  Golf ball no. 1-4, in which the cover has, as a resin component, (a) a hydrogenated block copolymer, (b) an olefin polymer, (c) a silane compound, (d) an organic peroxide, and (c) It is formed from a cover composition containing a resin composition obtained by reacting a rubber softener. These golf balls No. 1-4 are all excellent in scuff resistance and resilience.

  Golf ball no. 5 is a case where divinylbenzene is contained instead of (c) the silane compound, but crosslinking has progressed during the molding of the cover, and the cover could not be molded. Golf ball no. Nos. 6 and 7 are cases where the cover is formed from (c) a composition for a cover that does not contain a silane compound, but both have poor scratch resistance. Golf ball no. Nos. 8 and 9 are cases where the cover is formed from a cover composition containing only thermoplastic polyurethane as a resin component, but both have poor scratch resistance.

  The present invention relates to a golf ball. More specifically, the present invention is useful for a golf ball having excellent scratch resistance and resilience.

Claims (12)

A golf ball having a core and a cover covering the core,
The cover is a resin component,
(A) hydrogenated block copolymer having at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block, (b) an olefin polymer, (c) the following general formula ( A golf ball comprising a cover composition containing a resin composition obtained by reacting the silane compound represented by 1) and (d) an organic peroxide.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]   The golf ball according to claim 1, wherein the cover composition is obtained by further adding (f) a silanol condensation catalyst composition to the resin composition.   The component (a) is a hydrogenated product of a block copolymer having at least two styrene blocks as vinyl aromatic hydrocarbon polymer blocks and at least one butadiene block as conjugated diene polymer blocks. Or the golf ball of 2.   The block copolymer constituting the component (a) has a weight average molecular weight of 160,000 or less, and the content of the vinyl aromatic hydrocarbon polymer block in the block copolymer is 25% by mass to 70% by mass. The golf ball according to claim 3, which is%. Wherein component (b), (b-1) Bending and propylene polymer modulus 100MPa~1800MPa, (b-2) density of 0.870g ^/ cm ³ ~0.910g ^/ cm 3 of the ethylene The golf ball according to claim 1, comprising a polymer.   The golf ball according to claim 2, wherein the component (f) is a compound having a sulfonic acid group or an organotin compound.   The golf ball according to any one of claims 1 to 6, wherein the resin composition is obtained by further reacting (e) a rubber softener in addition to the components (a) to (d). . The blending ratio of the component (a), component (b) and component (e) (total 100% by mass) in the resin composition is (a) component / (b) component / (e) component = 20% by mass- 80 mass% / 5 mass% -50 mass% / 1 mass% -40 mass%,
The amount of the component (c) is 0.01 part by mass to 10 parts by mass with respect to 100 parts by mass of the total amount of the component (a), the component (b) and the component (e),
The blending amount of the component (d) is 0.01 part by mass to 3 parts by mass with respect to 100 parts by mass of the total amount of the component (a), the component (b), and the component (e). Golf ball.   The blending amount of the component (f) in the cover composition is 0.2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the resin component. Golf ball.   The cover composition has a rebound resilience of 40% to 70%, a slab hardness of 75 to 98 in Shore A hardness, a flexural modulus of 10 MPa to 300 MPa, and a three-dimensional crosslinking ratio of 15 to 50% by weight. Item 10. The golf ball according to any one of Items 1 to 9. (A) hydrogenated block copolymer having at least one vinyl aromatic hydrocarbon polymer block and at least one conjugated diene polymer block, (b) an olefin polymer, (c) the following general formula ( A step of preparing a resin composition by reacting the silane compound represented by 1) and (d) an organic peroxide;
A method for producing a golf ball comprising: preparing a cover composition using the obtained resin composition, and molding a cover from the cover composition.

[Wherein, R ¹ represents an ethylenically unsaturated hydrocarbon group, R ² represents an alkyl group having 1 to 12 carbon atoms, Y represents a hydrolyzable group, and n represents 0, 1 or 2]   The golf ball manufacturing method according to claim 11, wherein in the step of forming the cover, the cover composition is prepared by further adding (f) a silanol condensation catalyst composition to the resin composition.