JPH0439865B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a golf ball that provides durability, rebound resilience (flight characteristics), and excellent feel when hit. (Prior Art) Golf balls are required to have flight stability, long-distance flight performance, etc., and these characteristics require well-controlled rebound resilience, compressive strength, hardness, etc. Various proposals have been made for improving the quality of compositions. For example, it relates to a solid golf ball in which metal salt monomers of α,β-monoethylenically unsaturated carboxylic acids are added to a rubber composition, and these monomers are activated by a free radical initiator to form a rubber component. It is grafted onto the main chain of polybutadiene used as a polybutadiene and acts as a co-crosslinking agent, thereby giving the ball hardness, but a solid ball that is satisfactory in terms of durability and impact resilience has not been obtained. Further, the hardness of the golf ball can be adjusted by adjusting the amount of crosslinking agent, but if the amount is too large, the impact resilience will eventually decrease. Furthermore, various proposals have been made regarding fiber materials and fine particulate materials to improve the hardness, durability, and high resilience of rubber compositions, but at present, they all result in a decrease in durability and resilience, and little improvement can be expected. It was hot. Furthermore, although the fine fiber material is homogeneously dispersed in the rubber structure, it has poor wettability with the rubber material, and surface treatment of the fiber surface has been a major problem. Although it has been known that hydrolyzable silyl compounds are effective as a surface treatment technique for these, it requires a high degree of skill. Although it has been found that sulfur-containing silane compounds are excellent surface treatment agents with good compatibility with rubber components, these are all related to sulfur vulcanization systems, and conventionally, sulfur-containing compounds have been used for sulfur vulcanization systems. The curing mechanism inhibited vulcanization with non-sulfur-based vulcanizing agents, and it was thought to be impractical. (Problems to be Solved by the Invention) An object of the present invention is to provide a golf ball with excellent durability, rebound resilience, and hardness. Another object of the present invention is to provide a golf ball reinforced with a fibrous material surface-treated with a sulfur-containing compound that does not inhibit vulcanization even with non-sulfur vulcanizing agents. (Means for Solving the Problems) The present invention provides a thread-wound golf ball comprising a spherical core, a portion around which an elastic thread is wound under tension, and a covering layer, in which the spherical core has the following general formulas () and ( ) A fibrous alkali metal titanate surface treated with a surface treatment agent selected from mercapto group-containing silane compounds and silyl group-containing sulfide compounds shown in ) and one or more mixtures of synthetic rubber and/or natural rubber. The present invention relates to a golf ball characterized by comprising: Various known rubbers can be used as the rubber component of the present invention, such as natural rubber (NR),
Isoprene rubber (IR), styrene-butadiene rubber (SBR), nitrile rubber (NBR), butadiene rubber (BR), chloropropylene rubber (CR), butyl rubber (IIR), acrylic rubber (AR), urethane rubber (UR), Silicone rubber (SiR), fluorocarbon rubber (FR), ethylene propylene rubber (EPR), chlorosulfonated polyethylene (CSM), ethylene acetate rubber (EVA), chlorinated polyethylene (CPE), polyisobutylene (PIB), Alfin rubber ( A.L.),
Examples include polyester rubber (ESR), epichlorohydrin rubber (ECR), chlorinated butyl rubber (CIR), and nitrile isobutylene rubber (NIR). Among these rubber components, cis-
It is particularly preferable to use a material containing 30% by weight or more of 1,4-structured polybutadiene because hardness and impact resilience are improved. The reason for this is not clear, but perhaps the sulfur component of the surface treatment agent for the fibrous alkali metal titanate reacts with the cis-1,4-structured polybutadiene, resulting in a reinforcing effect that effectively utilizes the fiber shape of the alkali metal titanate. This is thought to be due to the appearance of sulfur components, and surface treatment agents that do not contain sulfur components, such as methyltrimethoxysilane, methyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltriethoxysilane, are commonly used. Hardness and impact resilience are improved compared to those using alkoxysilane-based surface treatment agents. In the present invention, the fibrous alkali metal titanate has a fiber length of 1 μm to 1 mm and an aspect ratio of 5 to 1 mm.
It is preferable to have a fiber shape of 1000, particularly preferably an average fiber length of 5 to 300 μm, and an aspect ratio of 10 to 300 μm.
300, and those in this range have excellent reinforcing properties and homogeneous dispersibility, and can obtain a homogeneous strength distribution. Specific examples include sodium titanate fiber, potassium titanate fiber, lithium titanate fiber, etc., which have excellent reinforcing properties, heat resistance, whiteness, can be colored to the desired color tone, and have fine and uniform fiber length. Potassium titanate fiber is a particularly suitable material because it can be easily produced and has high homogeneous dispersibility as a composite material. Potassium titanate fiber has the general formula _K2O・
It means a single crystal fiber represented by nTiO ₂ or the general formula K ₂ O・nTiO ₂・1/2H ₂ O (in both formulas, n represents an integer from 2 to 8), specifically, tetratitanic acid. Potassium fibers, potassium hexatitanate fibers, potassium octitanate fibers, etc. may be used alone, or two or more thereof may be used in combination. The average fiber diameter of these potassium titanate fibers is 0.1
-2 μm, average fiber length of 5-100 μm, and spectral ratio of 10-200. Here, the average fiber diameter and the average fiber length are the average values of the values measured for at least 10 or more fibers per field, examined using a scanning electron microscope in at least 5 or more fields of view, and the aspect ratio means the value obtained by dividing the average fiber length of such fibers by the average fiber diameter. In the present invention, examples of the surface treatment agent for treating the surface of the fibrous alkali metal titanate include sulfur-containing silane compounds such as mercapto group-containing silane compounds and silyl group-containing sulfide compounds. A typical example of the above mercapto group-containing silane compound is the general formula (R ¹ is a substituted or unsubstituted divalent hydrocarbon group having 2 to 6 carbon atoms, R ² is a substituted or unsubstituted monovalent hydrocarbon group, X is a hydrolyzable group, a is a 1 to 3 carbon number integer,
b is an integer from 0 to 2, and 1≦(a+b)≦. ) is a compound represented by Examples of R ¹ include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group, with an ethylene group and a trimethylene group being preferred, and a trimethylene group being particularly preferred. R ² is an alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl, octadecyl; alkenyl such as vinyl or allyl; phenyl aryl group such as tolyl group; aralkyl group such as benzyl group, β-phenylethyl group, β-phenylpropyl group; β-cyanoethyl group, γ-chloropropyl group 3,3,3
- Substituted hydrocarbon groups such as trifluoropropyl group and chlorophenyl group are exemplified, and various groups are selected depending on the type of rubber component and purpose of use. The group is effective for rubber components containing aromatic rings, and the substituted hydrocarbon group is effective for rubber components containing halogens, nitriles, etc. X is a hydrolyzable group bonded to a silicon atom; an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group; Alkoxy group; Enoxy group such as isopropenyloxy group; Ketooxymato group such as dimethylketooximato group, methylethylketooximato group; Amino group such as diethylamino group, dibutylamino group; Aminoxy group such as diethylaminoxy group; Acetoxy group, octa Examples include acyloxy groups such as a noyloxy group; and amide groups such as an N-methylacetamide group. Among these, lower alkoxy groups having 1 to 4 carbon atoms are preferred because they have excellent surface reactivity with fibrous alkali metal titanates, and among these, methoxy groups are particularly preferred because they have good reactivity. a is an integer of 1 to 3, preferably less than 2 on average, b is an integer of 0 to 2,
An average of 1 or less is preferable. If a and b are too large, the number of hydrolyzable groups will decrease and the reactivity with the fibrous alkali metal titanate will decrease, and if a is too small, the effect of the mercapto group on the rubber component will decrease. Preferably, the average value of a is adjusted to 1, and the average value of b is adjusted to less than 1. A typical example of a silyl group-containing sulfide compound is the general formula (R ³ is the same or different substituted or unsubstituted monovalent hydrocarbon group, R ⁴ is the same or different substituted or unsubstituted hydrocarbon group having 2 to 4 carbon atoms, Y is a hydrolyzable group , c is an integer of 0 to 2, and n is an integer of 1 to 6). R ³ is an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, octadecyl group; alkenyl group such as vinyl group or allyl group; phenyl group group, aryl group such as tolyl group; aralkyl group such as benzyl group, β-phenylethyl group, β-phenylpropyl group; β-cyanoethyl group, γ-chloropropyl group, 3,3,
Substituted hydrocarbon groups such as 3-trifluoropropyl group and chlorophenyl group are exemplified, and various groups are selected depending on the type of rubber component and purpose of use. Aralkyl groups are added to rubber components containing aromatic rings,
Also, substituted hydrocarbon groups are effective for rubber components containing halogens, nitriles, and the like. Examples of R ⁴ include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group, with an ethylene group and a trimethylene group being preferred, and a trimethylene group being particularly preferred. Y is a hydrolyzable group bonded to a silicon atom, and includes alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy groups; Alkoxy group; Enoxy group such as isopropenyloxy group; Ketooxymato group such as dimethylketooximato group, methylethylketooxymato group; Amino group such as diethylamino group, dibutylamino group; Aminoxy group such as diethylaminoxy group; Acetoxy group, octoxy group; Examples include acyloxy groups such as a noyloxy group; and amide groups such as an N-methylacetamide group. Among these, lower alkoxy groups having 1 to 4 carbon atoms are preferred because they have excellent surface reactivity with fibrous alkali metal titanates, and among these, propoxy groups are particularly preferred because they are easily synthesized and are stable compounds. c is an integer of 0 to 2, and there is at least one, preferably two, hydrolyzable groups that react with the surface of the fibrous alkali metal titanate in one molecule of the silyl group-containing sulfide compound represented by the general formula (). It is desirable that c is included, and c is preferably less than 2 on average. n is an integer from 1 to 6, ease of synthesis,
An average of 2 to 4 due to the relationship between affinity with rubber and vulcanization inhibition.
is preferred. In the present invention, the surface of the fibrous alkali metal titanate is treated with a surface treatment agent, and the amount of the surface treatment agent of the present invention used is generally about 0.05 to 10% by weight based on the fibrous alkali metal titanate. It is preferable to keep it in the range of . Within this range, the surface of the fibrous alkali metal titanate is sufficiently modified, and the physical properties of the rubber composition can be improved without inhibiting vulcanization during vulcanization, which will be described later. For the treatment method using the surface treatment agent of the present invention, any commonly used surface treatment method may be used. For example, the surface treatment agent of the present invention or its diluted solution is sprayed onto the fibrous alkali metal titanate surface. A method of homogeneous mixing with the fibrous alkali metal titanate or an impregnation treatment method can be adopted, and after the surface treatment agent of the present invention is uniformly adhered to the surface of the fibrous alkali metal titanate, the surface treatment agent is heated, dried, and hydrated. By performing decomposition or the like, the surface treatment agent of the present invention can be uniformly fixed to the surface of the fibrous alkali metal titanate. The surface treatment agent of the present invention contains a sulfur element in the molecule, and in particular, the terminal mercapto compound is a sulfur-containing compound that has been thought to inhibit vulcanization during peroxide-based vulcanization and deteriorate rubber physical properties. Although it is not clear by what mechanism of action the effect is expressed in the rubber composition, when fibrous alkali metal titanate is used, the effect is clearly expressed and the effect is achieved without inhibiting vulcanization. In addition to being homogeneously vulcanized, the fibrous alkali metal titanate and the rubber material are strongly bonded, and the sliding phenomenon at the interface between the fibrous filler and the rubber matrix, which is considered to be the cause of the decline in physical properties in composite materials, is eliminated. A rubber composition with high hardness and high compressive strength can be obtained. In the present invention, unsaturated carboxylic acids, salts thereof, other unsaturated vinyl compounds, etc. can be used as crosslinking monomers. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, 2-acetaminoacrylic acid, β,β-dimethacrylic acid, ethacrylic acid, α-chloroacrylic acid, cinnamic acid, acotic acid, 2-ethyl-3-propyl Acrylic acid, crotonic acid, aminocrotonic acid, acidophoshydroxyethyl (meth)acrylate, β
-Acryloxypropionic acid, 2-butene-
1,4-dicarboxylic acid, sorbic acid, acetylcarboxylic acid, N-butylmaleamic acid, fumaric acid,
Maleic acid, chlormaleic acid, di-n-butylmaleamic acid, N,N-dimethylmaleamic acid,
N-ethylmaleadic acid, N-phenylmaleadic acid, dichloromaleic acid, dihydroxymaleic acid, allylarsonic acid, chlorendeic acid,
Examples of other unsaturated vinyl compounds include vinyl compounds such as vinyl acetate, vinyl propionate, vinyl caproate, styrene, vinyltoluene, and divinylbenzene; acrylic acid, and methacrylic acid. Examples include alkyl esters such as; (meth)acrylic acid derivatives such as (meth)acrylonitrile, (meth)acrylamide, and glycidyl (meth)acrylate; and various compounds such as triallyl isocyanurate. Among these, acrylic acid,
Preference is given to methacrylic acid, cinnamic acid, acotic acid, crotonic acid, itaconic acid and benzoyl acrylic acid. These compounds can be used alone or in a mixture of two or more. In the present invention, metal salts of the above-mentioned unsaturated carboxylic acids can also be used, and representative examples of the metals include lithium, sodium, potassium, strontium, zinc, magnesium, calcium, barium, cadmium, lead, zirconium, beryllium, copper, and aluminum. , tin, iron,
Any one type or a mixture of two or more of antimony, bismuth, molybdenum, tungsten, nickel, etc. can be used, and divalent or higher metal salts are preferred because they increase the crosslinking effect, are easily available, and have low toxicity. Among them, calcium, zinc, magnesium, zirconium, etc. are preferred. In addition, these metal species can be used not only as metal salts of unsaturated carboxylic acids that have been previously reacted with unsaturated carboxylic acids, but also as unsaturated carboxylic acids and these metals, metal oxides, hydroxides, and carbonates. etc. are mixed separately into the rubber component,
It is also possible to react in a mixed system to form a metal salt. In the present invention, the amount of crosslinking monomer used is not particularly limited, but is 0.1 to 50 parts by weight, preferably 1 to 15 parts by weight, more preferably 3 parts by weight, based on 100 parts by weight of the rubber component.
~9 parts by weight, and within this range, durability is excellent and the hardness of impact resilience can be easily adjusted. Examples of the non-sulfur vulcanizing agent of the present invention include metal oxides such as magnesium oxide, lead oxide, and zinc oxide;
Crosslinkable resins such as phenolic resins, melamine formaldehyde resins, urethane resins, polyester resins, polyamide resins, and epoxy resins, and low molecular weight products or modified products thereof; diacetyl peroxide, dibenzoyl peroxide, dicapryl peroxide, di(p- chlorobenzoyl peroxide, didecanoyl peroxide, di(2,4-dichlorobenzoyl) peroxide, diisobutyl peroxide, diisonanoyl peroxide, dilauroyl peroxide, diperagonyl peroxide, dipropynyl peroxide, Di(β-carboxypropinoyl) peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide,
Dihydroxy-dimethyl-dioxacyclopentane, t-butyl peroxide, t-butyl peroxy (2-ethylhexanoate), t-butyl peroxyisobutyrate, O,O-t-butyl-O-isopropyl Monoperoxycarbonate, t-butylperoxypivalate, dimethyl-di(benzoylperoxy), hexane, t
-butyl peroxy (2-ethyl butyrate),
Di-t-butyl peroxide, dicumyl peroxide, dimethyl-bis(t-butylperoxy), hexane, t-butyl hydroperoxide, walnut hydroperoxide, bis(t-butylperoxy)trimethylcyclohexane, n -Butylbis(t-butylperoxy)
Examples include organic peroxides such as valerate.
Among these, dicumyl peroxide, cumyl hydroperoxide, t-butyl peroxide, dibutyl oxide, bis(t-butylperoxy)trimethylcyclohexane, n-
Butyl bis(t-butylperoxy)valerate and the like are suitable because vulcanization proceeds homogeneously due to the relationship between vulcanization temperature and half-life. These non-sulfur vulcanizing agents can be used alone or as a mixture of two or more, and the amount used is arbitrarily selected depending on the type of rubber used, the purpose of use of the rubber composition, etc. Preferably, it is used in a range of about 0.1 to 15% by weight based on the ingredients. In the present invention, it is possible to add various known additives, such as vulcanization accelerators, vulcanization retarders, anti-aging agents, plasticizers, plasticizers, tackifiers, anti-blocking agents, blowing agents, A dispersant, powder, mold release agent, solvent, softener, etc. can be added as necessary. Furthermore, in the present invention, carbon black, magnesium carbonate, zinc oxide, calcium carbonate, barium sulfate, aluminum hydroxide, aluminum oxide, silica powder, titanium oxide, mica, talc,
Various inorganic fillers such as clay powders such as clay, diatomaceous earth, and kaolin, and arbitrary pigments and dyes as coloring agents can also be used in combination. Also, any resin commonly used as an organic modifier, such as coumaron indene resin, phenol resin, polystyrene resin, acrylic resin, polyamide resin,
Epoxy resin, urethane resin, polyolefin resin, etc. may be mixed and used. Furthermore, in the present invention, commonly used long fiber reinforcing agents such as glass fiber,
Inorganic fibers such as carbon fibers, metal fibers, quartz fibers, ceramic fibers; nylon fibers, vinylon fibers, polyester fibers, aromatic polyamide fibers,
Organic fibers such as polyimide fibers and aromatic polyetheramide fibers can also be used in combination. The golf ball of the present invention includes a fibrous alkali metal titanate treated with the above-mentioned surface treatment agent, a rubber component, a vulcanizing agent, and various additives added as necessary.
After kneading the auxiliary agents etc. in the usual way, at about 80 to 180℃
It is obtained by molding a golf ball after vulcanization for 60 minutes, but the composition ratio of each component is adjusted depending on the type of rubber component and the purpose of use and cannot be specified, but it is a combination of surface-treated fibrous alkali metal titanate. The amount is usually about 2 to 100 parts by weight of the rubber component.
100 parts, particularly preferably about 10 to 50 parts; if too small, it will be soft but difficult to develop strength;
On the other hand, if the amount is too large, the strength will increase, but it will be too hard and the elongation rate will be insufficient, making it impractical. In the present invention, a spherical core made of elastic rubber as described above is used, the surface of which is wound with an elastic thread under tension in a conventional manner, and the upper surface is further coated with a hard elastic material to form a spherical golf ball with dimples, etc. It can be obtained by molding or by treating its surface with a conventional coating material. As the elastic system, known materials can be used; for example, elastic threads obtained by a known thread rubber manufacturing method using natural rubber (NR), polyisoprene rubber (IR), a blend thereof, etc. as a base material can be used. . Suitable examples of the hard elastic material include ionomer resins and transpolyisoprene resins. The ionomer resin has the general formula R-CH=
A copolymer of an α-olefin represented by CH ₂ (wherein R is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms) and an α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms, Examples include ionic copolymers obtained by reacting with metal compounds. The α-olefins include ethylene, propylene, butene-1, pentene-1, and hexene-1.
1, heptene-1,3-methylbutene-1,4-
Examples include methylpentene-1. Further, α-olefins having a large number of carbon atoms can also be used in the present invention, but they are difficult to obtain and lack practicality. These α-olefins may be used alone or in combination of two or more. The content of α-olefins in the copolymer is preferably at least 50 mol%, and preferably more than 80 mol% in terms of processability and physical properties. Examples of the α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms include acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, etc.; maleic acid, fumaric acid, etc., or monoesters of these dicarboxylic acids, such as maleic acid monomethyl ester. , fumaric acid monoethyl ester, and acid anhydrides of these dicarboxylic acids, such as maleic anhydride, but are not limited thereto. These α,β-unsaturated carboxylic acids may be used alone or in combination of two or more. α, β−
The content of unsaturated carboxylic acid in the copolymer is
0.5-25 mol% is preferable, and 1-10 mol% is more preferable. In addition, as a component other than α-olefin and α,β-unsaturated carboxylic acid, monomers copolymerizable with these, such as styrene, vinyl chloride, vinyl acetate, acrylonitrile, and vinyl methyl ether, may be used as a part of α-olefin. It is also possible to replace and copolymerize. The copolymer consisting of α-olefin and α,β-unsaturated carboxylic acid is not limited to one obtained by directly copolymerizing a mixture of monomers, but can be obtained from α-olefin. It may be obtained by graft polymerizing an α,β-unsaturated carboxylic acid monomer onto a base polymer. An ionic copolymer is obtained by reacting (neutralizing) the thus obtained copolymer with a metal compound that generates metal ions. Metal ions suitable for producing the ionic copolymers include metal ions of group 1 or 2 of the periodic table, namely Na, K, Li, Cs, Cu, Ag and Be,
Examples include Mg, Ca, Sr, Zn, Cd, and Hg, and these may be used alone or in combination of two or more. When these metal ions are used, cross-linking is suitably formed in the formation of an ionic copolymer. Among these metal ions, Na,
Zn is more preferred from the viewpoint of melt processability and physical properties in a solid state. The amount of ions used or the degree of neutralization of the copolymer cannot be determined unconditionally because it depends on the desired solid state properties and meltability of the ionic copolymer obtained. To effect a significant change in the solid state of the polymer, the amount is preferably such that it neutralizes at least 10% of the carboxyl groups in the copolymer, and can usually neutralize up to about 90%. .
The degree of neutralization to optimize the physical properties of an ionic copolymer varies depending on the use, and the physical properties of the ionic copolymer also vary depending on the carboxyl group concentration in the copolymer and the molecular weight of the copolymer. It is generally desirable to neutralize at least 50% of the carboxyl groups, although this cannot be determined unconditionally because of the differences in the carboxyl groups. The above-mentioned metal ions can be obtained by hydrating metal compounds that generate such metal ions, such as inorganic compounds such as sodium hydroxide and sodium carbonate, or organic metal compounds such as sodium methoxide, sodium formate, and sodium acetate. Alternatively, it can be obtained by dissolving it in an organic solvent such as methanol. There is no particular limitation on the method for obtaining the ionic copolymer from the copolymer and metal ions, and any known method may be used. The molecular weight of the ionic copolymer thus obtained is appropriately expressed by MI (melt index), which is a measure of melt viscosity described in ASTM D 1238. The range of MI of useful ionic copolymers is about 0.1 to 100 g/10 minutes (190°C), more preferably about 0.5 to 20 g/10 minutes (190°C). MI of ionic copolymers
is about 0.1 to 100g/10 minutes (190℃),
It has excellent melt processability and is extremely strong in the solid state, with appropriate elasticity and flexibility. In the present invention, these ionomer resins may be used in combination with commonly used fillers such as titanium oxide, talc, calcium carbonate, and silica, but in particular, in the present invention, titanium oxide, talc, calcium carbonate, silica, and other commonly used fillers may be used. It is effective to utilize the technology related to JP-A-60-202142 using acid potassium fibers. In the present invention, the trans polyisoprene resin exists as a main component of naturally occurring balata and gutta percha, and has a molecular structure of trans-1,4-polyisoprene. Kuraray Trans Polyisoprene TP is a typical example of a commercially available product.
-301 [Clare Isoprene Chemical Co., Ltd.]. In the present invention, after kneading the fibrous alkali metal titanate treated with the above-mentioned surface treatment agent of the present invention, a rubber component, a vulcanizing agent, and various additives and auxiliary agents added as necessary, in a conventional manner, A spherical core is created by vulcanization at the same time as the spherical molding process, and a spool core material is formed by winding an elastic thread under tension.The surface of the spool core is further covered with a hard elastic material, molded, and processed as necessary. A golf ball can be obtained by sulfurizing. In the present invention, the surface may be treated with a commonly used coating agent. (Example) Examples and comparative examples will be described below. Examples 1 to 4 and Comparative Examples 1 to 6 All components listed in Table 1 were added to a kneader, except for the vulcanizing agent, and heated at 60 to 100°C for 10 minutes.
After kneading for a minute, the contents were cooled to 60-70℃, a vulcanizing agent was added, the weight was adjusted, and the mixture was kneaded, followed by vulcanization at 150±5℃ for 30 minutes in a regular golf ball core mold. A core material was obtained by winding an elastic thread (NR-based rubber thread) around the obtained spherical core. This core material was coated with a mixture of 100 parts of ionomer resin and 10 parts of titanium oxide so that each ball weighed 45 g, and injection molded using an injection machine to obtain a thread-wound golf ball. The resulting balls were measured for their rebound resilience, durability, compression, and actual impact. The results are shown in Table 1. In addition, in the table *1 Nippon Synthetic Rubber BR-11 *2 Nippon Synthetic Rubber STEREON 720 *3 Nippon Synthetic Rubber IR-2200 *4 Seido Kagaku No. 3 Zinc White *5 Nippon Silica Nipseal VN3AQ Potassium titanate (untreated product) Otsuka Chemical Co., Ltd.
Manufactured by Teismo D. Processed product A is Teismo D treated with 1% bis(3-triethoxysilylpropyl)tetrasulfide, and processed product B is Teismo D treated with 1% γ-mercaptopropyltrimethoxysilane. Processed product C is Teismo D treated with 1% γ-mercaptopropyltriethoxysilane, and Processed product D is Teismo D treated with 1% bis(3-trimethoxysilylpropyl)tetrasulfide. Treated product E is Teismo D treated with 1% γ-glycidoxypropyltrimethoxysilane. In addition, the durability index is expressed as an index by measuring the number of times until it breaks after applying compression that deforms it by 10 mm, and taking Example 1 as 100, and rebound resilience is based on JIS S7005.
It was dropped from a height of 120cm and the rebound height was measured at a measurement temperature of 20℃, and the compression showed the strength when compressed by 2.54mm. Examples 11-14 In Examples 1-4, potassium titanate (treated product A) was added to 100 parts of ionomer resin as a coating layer.
A thread-wound golf ball was prepared in the same manner except that a hard elastic body containing 10 parts of the compound was used. The results are also shown in Table 2. Examples 21-24 and Comparative Examples 21-26 Thread-wound golf balls were prepared in the same manner as Examples 1-4, except that the spherical core composition shown in Table 3 was used. The results are also shown in Table 3. Examples 31 to 34 In Examples 21 to 24, potassium titanate (treated product A) was added to 100 parts of ionomer resin as a coating layer.
A thread-wound golf ball was prepared in the same manner except that a hard elastic body containing 10 parts of the compound was used. The results are also shown in Table 4. Examples 41 to 49 Core materials obtained from the same spherical core formulation as in Example 22 were coated with various coating layers shown in Table 5 to prepare thread-wound golf balls. The results are also shown in Table 5. Examples 50 to 60 Wound golf balls were made using the spherical core formulations shown in Table 6. In addition, as a coating layer, Example 43 was used for Examples 50 to 52, and Example 43 was used for Examples 53 to 56.
47, Examples 57 to 60 used the same material as Example 44. The results are also shown in Table 6.

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Claims (1)

[Claims] 1. In a thread-wound golf ball consisting of a spherical core, a portion around which an elastic thread is wound under tension, and a covering layer, the spherical core has a general formula. (R ¹ is a substituted or unsubstituted divalent hydrocarbon group having 2 to 6 carbon atoms, R ² is a substituted or unsubstituted monovalent hydrocarbon group, X is a hydrolyzable group, a is a 1 to 3 carbon number integer,
b is an integer from 0 to 2, and 1≦(a+b)≦3. )
Mercapto group-containing silane compound and general formula represented by (R ³ is the same or different substituted or unsubstituted monovalent hydrocarbon group, R ⁴ is the same or different substituted or unsubstituted hydrocarbon group having 2 to 4 carbon atoms, Y is a hydrolyzable group , c is an integer of 0 to 2, and n is an integer of 1 to 6. A golf ball characterized by being made of one type or a mixture of two or more types of natural rubber. 2. The spherical core is made of (a) a fibrous alkali metal titanate surface treated with the above surface treatment agent, (b) one or a mixture of two or more of synthetic rubber and/or natural rubber, and (c) a crosslinkable monomer. The golf ball according to claim 1, which is obtained by vulcanizing a mixture of a weight adjuster and a weight adjuster with a non-sulfur vulcanizing agent. 3 At least one of the synthetic rubber and/or natural rubber or a mixture of two or more of them is cis-1,4
-Claim 2 which is structural polybutadiene
The golf ball described in Section 1. 4. The golf ball according to claim 2, wherein the crosslinking monomer is an unsaturated carboxylic acid, a salt thereof, or an unsaturated vinyl compound. 5. The golf ball according to claim 1, wherein the coating layer is a fibrous alkali metal titanate-containing elastic body whose surface has been treated with the surface treatment agent. 6. The golf ball according to claim 5, wherein the elastic body forming the coating layer is an ionomer resin. 7. The golf ball according to claim 5, wherein the elastic body forming the coating layer is a trans polyisoprene resin.