JP2000245871A - Solid golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid golf ball of which the ball-hitting feeling, the control property and the finished appearance are favorable, and which is excellent in a repelling perfarmance and flying performance. SOLUTION: In this solid golf ball equipped with a core and a cover, the core is formed of a rubber composition containing 20-40 pts.wt. of a metal salt of an unsaturated carboxylic acid, 0.05-3.0 pts.wt. of an organic sulfuric compound, and 0.3-3.0 pts.wt. of a co-crosslinking starting agent, based on 100 pts.wt. of a base material rubber. Also, the cover is formed of a resin composition containing 50-90 pts.wt. of a binary copolymer based ionomer, 5-30 pts.wt. of a ternary copolymer based ionomer, 1-20 pts.wt. of a polyamide based thermoplastic elastomer resin, and 1-15 pts.wt. of an epoxidized diene based block copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid golf ball having a core and a cover, and more particularly, to a solid golf ball excellent in shot feeling, controllability and finished appearance, and excellent in rebound performance and flight performance. It is about.

[0002]

2. Description of the Related Art There are roughly two types of golf balls used so far. One is a thread wound golf ball. This thread-wound golf ball has a thread or rubber wound around a liquid or solid center and covered with a cover mainly composed of balata (trans polyisoprene) or an ionomer resin. The other is a solid golf ball such as a two-piece ball or a three-piece ball. This solid golf ball has a core made of a rubber member covered with a thermoplastic resin cover containing an ionomer resin and the like. Also excellent in flight performance. On the other hand, solid golf balls have a hard hitting feel, and have a small contact area between the hitting surface of the golf club and the ball at the time of hitting, making it difficult for spin to be applied and insufficient controllability on approach shots and the like. He was often shunned by professional golfers and advanced amateur golfers who value the feel and control.

Various proposals have been made so far to solve the above problems. For example, JP-A-4-10997
No. 0 proposes forming a core ball using a rubber composition containing a specific component in a multilayer solid golf ball having a core ball and a cover material. However, such a proposal is an improvement only from the material side of the core sphere, and its improvement effect is naturally limited. Also, JP-A-8-15
Japanese Patent Publication No. 5053 proposes that a golf ball having a core and a cover is formed with a specific resin mixture as a main component. According to this proposal, the cover is softened and the controllability is improved, but the resilience performance is not yet at a satisfactory level, and in addition, the compatibility between the polyamide elastomer resin and the ionomer is poor, so that the outermost layer cover There was a problem to use. JP-A-9-176429 proposes to form a cover with a thermoplastic resin composition obtained by mixing a specific resin. According to this proposal, although good flexibility and resilience performance can be obtained, the compatibility with the ionomer and the epoxidized diene-based block copolymer is poor due to the large content of the polyamide-based elastomer resin. However, there was a problem in using it as a cover of the outermost layer.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is intended to provide a solid golf ball which is excellent in shot feeling, controllability and finish appearance, and excellent in rebound performance and flight performance. Its purpose is to provide.

[0005]

According to the present invention, in a solid golf ball provided with a core and a cover, the core contains 20 to 40 parts by weight of a metal salt of an unsaturated carboxylic acid per 100 parts by weight of a base rubber. Parts by weight, 0.05 parts organic sulfur compound
To 3.0 parts by weight, a rubber composition containing 0.3 to 3.0 parts by weight of a co-crosslinking initiator, and the cover is formed of 50 to 90 parts by weight of a binary copolymer ionomer, It is formed of a resin composition containing 5 to 30 parts by weight of a copolymeric ionomer, 1 to 20 parts by weight of a polyamide-based thermoplastic elastomer resin, and 1 to 15 parts by weight of an epoxidized diene-based block copolymer. Is provided.

Here, the amount of deformation of the core when a load of 10 kg to 130 kg is applied is preferably in the range of 3.0 to 4.5 mm. The cover preferably has a flexural rigidity in the range of 1,300 to 3,000 kg / cm ² and a Shore D hardness of 56 to 68. The deformation amount of the golf ball when a load of 10 kg to 130 kg is applied is 2.5 to 3.7 mm.
Is desirably within the range.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have found that a solid golf ball maintains the excellent flight performance and rebound performance inherently possessed by a solid golf ball, while having a shot feeling, controllability and finish appearance equal to or better than a thread-wound golf ball. As a result of various studies as to whether or not it is possible to impart a specific material, the above performance is obtained by forming a core using a rubber composition containing a specific substance in a specific amount, and forming a cover using a resin composition containing a specific substance in a specific amount. The present inventors have found that a solid golf ball having the same can be obtained, and have accomplished the present invention.

That is, one of the major features of the present invention is that, based on 100 parts by weight of the base rubber, the metal salt of the unsaturated carboxylic acid is 20 to 40 parts by weight, and the organic sulfur compound is 0.05 to 40 parts by weight.
The core is formed by using a rubber composition having 3.0 parts by weight and a co-crosslinking initiator in an amount of 0.3 to 3.0 parts by weight. With this configuration, it is possible to obtain a core having low hardness and high resilience.

As the base rubber which can be used in the present invention, conventionally used natural rubber and synthetic rubber can be used. Among them, cis-1,4-polybutadiene rubber can be preferably used.
Preferably, it contains 80% or more. In addition, other natural rubbers, polyisoprene rubbers, styrene butadiene rubbers, EPDM
And the like may be added as needed.

The metal salt of an unsaturated carboxylic acid which can be used in the present invention is not particularly limited, and conventionally known ones can be used. Among these, a monovalent or divalent metal salt having 3 to 8 carbon atoms, such as zinc acrylate or zinc methacrylate, is desirable. When resilience is important, zinc acrylate is preferably used.

The content of the unsaturated carboxylic acid metal salt is in the range of 20 to 40 parts by weight, preferably 25 to 34 parts by weight, based on 100 parts by weight of the base rubber. When the content is less than 20 parts by weight, the hardness of the golf ball becomes insufficient, resulting in a heavy shot feeling. Also, the resilience performance may be deteriorated. On the other hand, if the content is more than 40 parts by weight, the hardness becomes too large, and a hard shot feeling may be obtained.

The organic sulfur compound that can be used in the present invention is not particularly limited. For example, thiophenols such as pentachlorothiophenol, 4-t-butylthiophenol and 2-benzamidothiophenol; thiocarboxylic acids such as thiobenzoic acid Diphenyl monosulfide;
Diphenyl disulfide, diphenyl polysulfide,
Morpholine disulfide, dixylyl disulfide,
Sulfides such as alkylated phenol sulfides and the like can be mentioned, and one or more of these can be used in combination. These organic sulfur compounds are S-
The bond between S or the bond between C and S is dissociated under vulcanization conditions to easily generate a radical, and the generated radical affects the butadiene main chain and the like. That is, it is considered that this affects the cross-linking system between the rubber and the unsaturated carboxylic acid, and improves the resilience performance without hardening the core, that is, ensuring the feel at impact.

The content of the organic sulfur compound as described above is as follows:
The range is 0.05 to 3.0 parts by weight, preferably 0.3 to 2.0 parts by weight, based on 100 parts by weight of the base rubber.
If the content is less than 0.05 part by weight, the above-mentioned effect due to the addition of the organic sulfur compound cannot be obtained. If the content is more than 3.0 parts by weight, the effect on the organic peroxide increases, and the hardness decreases. Regardless, the shot feeling is not improved, and the resilience performance is reduced, and the flight performance is reduced.

The co-crosslinking initiator which can be used in the present invention is not particularly limited. For example, dicumyl peroxide, di-
T-butyl peroxide and the like can be mentioned, and among them, dicumyl peroxide can be preferably used.
Such a co-crosslinking initiator is decomposed by heat to form a radical, thereby increasing the degree of crosslinking between the metal salt of the unsaturated carboxylic acid and the base rubber, thereby improving the resilience performance.

The content of such a crosslinking agent depends on the base rubber 1
The range is 0.3 to 3.0 parts by weight, preferably 0.5 to 2.5 parts by weight, per 100 parts by weight. If the content is less than 0.3 parts by weight, the hardness of the golf ball is insufficient, resulting in a heavy shot feeling, while if the content is more than 3.0 parts by weight,
The hardness becomes too large, giving a hard feel at impact.

The rubber composition constituting the core of the ball of the present invention contains, in addition to the above essential components, a core for golf balls such as a specific gravity adjuster, an antioxidant, a plasticizer, a dispersant, an ultraviolet absorber and a colorant. It is possible to appropriately mix ordinary additives to be added to the material as needed.

In the present invention, as a specific gravity adjusting agent to be added as required, a metal oxide or an inorganic metal salt, specifically, an inorganic substance generally used as an inorganic filler, such as zinc oxide, barium sulfate, or calcium carbonate, is used. Among them, zinc oxide, which also functions as a vulcanization aid in the vulcanization step, is particularly preferable. Zinc oxide and the like are usually blended as a modifier for lowering the specific gravity, but as a modifier for increasing the specific gravity, metal powder, metal oxide, metal nitride, specifically, tungsten, molybdenum, Metals such as lead, nickel and copper, or oxides, carbides and nitrides thereof can also be used. These specific gravity adjusters may be used alone or in combination of two or more, and the specific gravity may be adjusted by mixing a low specific gravity substance and a high specific gravity substance.

In the present invention, the rubber composition having the above-mentioned component composition is uniformly kneaded, heated and pressed in a mold, and vulcanized to form a core. Conditions at this time are not particularly limited, but are usually 130 to 180 ° C. and pressure 30 to 10
It is performed within a range of 0 kg / cm ² and 15 to 60 min.
When the core is composed of a plurality of layers, it is sufficient that the vulcanized molded article of the rubber composition constitutes one or more layers of the plurality of layers. It is constituted by a vulcanized molded article of the composition, and more preferably, the whole core is constituted by a vulcanized molded article of the rubber composition.

The outer diameter of the core (when the core has a multi-layer structure, the outer diameter of the outermost layer of the core) is preferably 32.0 to 40.5 mm, more preferably about 35.0 to 40.0 mm. If the outer diameter is too small, the excellent resilience performance of the core material cannot be effectively utilized, and if the outer diameter is too large, the cover is liable to be damaged and the durability tends to be deteriorated.

The resulting core has an amount of compression deformation (compression) of 3.0 to 4.5 mm, more preferably 3.3 to 4.3 mm, from when an initial load of 10 kg is applied to when a final load of 130 kg is applied. If it is less than 3.0 mm, it tends to be too hard and the feeling at the time of impact tends to be poor. On the other hand, if it exceeds 4.5 mm and the amount of compressive deformation is too large, the repulsion force is insufficient. It is difficult to obtain a satisfactory flight distance.

The core of the golf ball of the present invention (when the core has a single layer, it corresponds to a vulcanized molded article of the rubber composition).
Has a JIS-C hardness of preferably from 75 to 90 degrees, more preferably from 78 to 88 degrees. If the angle is smaller than 75 degrees, the resilience performance decreases, and if the angle is larger than 90 degrees, the impact feeling becomes too hard.

Another major feature of the present invention is that the binary copolymer ionomer is 50 to 90 parts by weight, the terpolymer copolymer ionomer is 5 to 30 parts by weight, and the polyamide thermoplastic elastomer resin is 1 to 20 parts by weight. The cover is formed by using a resin composition containing 1 to 15 parts by weight of the epoxidized diene-based block copolymer. In other words, while adding high hardness and high resilience performance to the cover by blending a binary copolymer type ionomer resin having high hardness and high resilience performance, this alone is inferior in hitting feeling and controllability, so it has a relatively low altitude. However, by blending an elastomer resin having high resilience performance, the shot feeling and controllability are improved. In addition, if the hardness of the conventional golf ball composed of a terpolymer ionomer and a binary copolymer ionomer resin is sufficient, the binary copolymer ionomer resin can be blended in a larger amount than usual, and High resilience performance. On the other hand, by adding a terpolymer ionomer resin having low resilience performance and low hardness, a good shot feeling and controllability can be imparted to the cover. At this time, the terpolymer ionomer resin also has an effect of improving the compatibility with the elastomer resin. However, the ternary copolymer-based ionomer resin alone is not enough to improve the compatibility, so that an epoxidized diene-based block copolymer that is soluble in both the ionomer resin and the elastomer resin is separately compounded as a compatibilizer. By blending each of the above resins in a specific amount, good shot feeling, controllability, resilience performance and finished appearance can be obtained.

Hereinafter, these resins will be described. First, the binary copolymer-based ionomer will be described. Its content is in the range of 50 to 90 parts by weight, preferably 55 to 8 parts by weight.
The range is 5 parts by weight. If the content is less than 50 parts by weight, the cover becomes too soft and the resilience performance may be reduced. On the other hand, if the content is more than 90 parts by weight, the cover hardness may be too hard and the shot feeling may be poor. The binary copolymer ionomer refers to a copolymer ionomer of ethylene- (meth) acrylic acid.

The binary copolymer ionomer that can be used in the present invention is not particularly limited as long as it is an ethylene- (meth) acrylic acid binary copolymer ionomer resin, and a metal ion for neutralizing a carboxyl group. As alkali metal ions such as Na ions, K ions, and Li ions; and Zn ions, Ca ions, and Mg ions.
Valent ions; trivalent ions such as Al ions and Nd ions, etc., can be used alone, and two or more of them can be used in combination. Among these metal ions, Na ions, Zn ions, and Mg ions are particularly preferable for improving durability and repulsion performance. Also, the content of each monomer is not particularly limited, but ethylene is 70 to 95 wt%.
Good to be included.

A specific example of a preferable binary copolymer ionomer resin is "Himilan 1555, 1706".
(Manufactured by DuPont-Mitsui Polychemicals), "IOTEC 8
000 "(manufactured by Exxon Chemical Co., Ltd.) and the like, but are not limited to these.

Next, the terpolymer ionomer resin will be described. The content is in the range of 5 to 30 parts by weight.
Preferably it is in the range of 8 to 25 parts by weight. When the content is less than 5 parts by weight, the hardness of the cover cannot be reduced and the shot feeling is deteriorated, and the compatibility is reduced, so that the durability of the cover is reduced and the workability in the manufacturing process may be reduced. is there. On the other hand, if the content is more than 30 parts by weight, the cover hardness may be too low and the resilience performance may be reduced.
Here, the terpolymer ionomer resin of the present invention means an ethylene- (meth) acrylic acid- (meth) acrylate terpolymer ionomer resin. As the ester group, a methyl group, an ethyl group, an n-butyl group, i
-Butyl group, t-butyl group, n-propyl group and the like. As the metal ion for neutralizing the carboxyl group, those exemplified for the aforementioned binary copolymer ionomer can be used.

The content of each monomer of ethylene, (meth) acrylic acid and (meth) acrylate in the terpolymer ionomer resin is not particularly limited. For example, ethylene is in the range of 20 to 90 wt%, The content of (meth) acrylic acid is preferably in the range of 5 to 30% by weight, and the content of (meth) acrylate is preferably in the range of 5 to 50% by weight.

Specific examples of preferred terpolymer ionomer resins include “Surlyn AD8542, 832”.
0, AM7316 "(manufactured by DuPont)," Himi Milan 1
855, 1856 "(manufactured by Du Pont-Mitsui Polychemicals)," IOTEC 7510, 7520 "(manufactured by Exxon Chemical Co., Ltd.) and the like, but are not limited thereto.

The polyamide-based thermoplastic elastomer resin that can be used in the present invention is a thermoplastic elastomer resin having a portion called a hard segment and a portion called a soft segment in a molecule and having polyamide as a hard segment. Specific examples of the elastomer resin include, for example, those commercially available from Toray Industries, Inc. under the trade name “Pebax”.

The content of the elastomer resin is from 1 to 20.
Parts by weight, preferably in the range of 3 to 15 parts by weight. If the content is less than 1 part by weight, the above-mentioned effect cannot be sufficiently exhibited. On the other hand, if the content is more than 20 parts by weight, the compatibility with the ionomer resin is deteriorated, the durability is reduced, and the workability in the production process is reduced.

Next, the epoxidized diene block copolymer will be described. The content is in the range of 1 to 15 parts by weight, preferably in the range of 2 to 10 parts by weight. If the content is less than 1 part by weight, the compatibility is reduced, so that the durability of the cover is reduced and the workability in the manufacturing process may be reduced. On the other hand, if the content is more than 15 parts by weight, the resilience performance of the cover may be reduced.

The epoxidized diene block copolymer is
A double bond derived from a conjugated diene compound of a block copolymer or a partially hydrogenated block copolymer is epoxidized. The block copolymer serving as the base is a block copolymer comprising a polymer block A mainly composed of at least one vinyl aromatic compound and a polymer block B mainly composed of at least one conjugated diene compound. It is. In addition, the partially hydrogenated block copolymer is obtained by hydrogenating the above block copolymer.

Examples of the vinyl aromatic compound constituting the block copolymer include styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene,
One or two of 1,1-diphenylethylene and the like
More than one kind can be selected and adopted, and styrene is particularly preferable.

Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene,
1 out of 2,3-dimethyl-1,3-butadiene, etc.
Species or two or more species can be selectively adopted, among which butadiene,
Isoprene and combinations thereof are preferred. Specific examples of the epoxidized diene-based block copolymer include, for example, “Epofriend A” from Daicel Chemical Industries, Ltd.
1010 ".

The cover containing the resin component described above is provided with a filler such as barium sulfate, a coloring material such as titanium dioxide, a dispersant, and the like, if necessary, in addition to the resin component as a main component.
An appropriate amount of an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent agent, a fluorescent bleach and the like can be added.

The cover in the present invention means a cover forming the outermost layer. That is, a golf ball such as a three-piece golf ball or a four-piece golf ball,
When the cover is laminated, it means the outermost cover of the cover. There is no particular limitation on the thickness of the cover, but it is in the range of 1.0 to 3.0 mm, and more preferably 1.3 to 3.0 mm.
A range of 2.5 mm is preferred. If the thickness is less than 1.0 mm, the original effect of the cover is not exhibited, while the thickness is 3.0.
When the thickness is larger than mm, the effect of the core is hardly exhibited.

The flexural rigidity of the cover is from 1,300 to 3,0.
In the range of 00 kg / cm ² , and more preferably in the range of 1,500 to 2,7
A range of 00 kg / cm ² is preferred. Rigidity is 1,30
If it is smaller than 0 kg / cm ² , the resilience performance of the cover may be insufficient, while the rigidity is 3,000 kg / cm ^2.
If it is larger than cm ² , the shot feeling may be deteriorated due to being too hard. Here, the flexural rigidity of the cover was determined by preparing a sheet of the cover composition having a thickness of about 2 mm by hot press molding, storing the sheet at 23 ° C. for 2 weeks,
It is a value measured according to IS K-7106.

The Shore D hardness of the cover is 56-6.
A range of 8 is preferable, and a range of 58 to 66 is more preferable. If the Shore D hardness is smaller than 56, the resilience performance of the cover may be insufficient. On the other hand, if the Shore D hardness is larger than 68, the shot feeling may be deteriorated due to too high hardness. The Shore D hardness of the cover was determined by preparing a sheet of the cover composition having a thickness of about 2 mm by hot press molding, storing the sheet at 23 ° C. for 2 weeks, and then measuring the surface of the sheet with ASTM D.
The value is a value measured by a Shore D type spring hardness tester specified in -2240.

There is no particular limitation on the method of forming the cover on the core, and the cover can be formed by a known method employed for molding a cover of a solid golf ball. Form a hemispherical shell half shell, wrap the two together and wrap the solid core, press molding at about 130-170 ° C. for about 1-15 minutes, or apply the cover composition directly on the solid core Examples include a method of injection molding and molding so as to surround the core.

A large number of pits, usually called dimples, are formed on the surface during cover molding, and a paint finish, a marking stamp, or the like is applied to enhance aesthetics and commercial value, thereby making the product into a product.

The solid golf ball of the present invention has an amount of deformation in a range of 2.5 to 3.7 mm when a load of an initial load of 10 kg to a final load of 130 kg is applied, more preferably 3.0 to 3.0 mm.
Preferably it is in the range of 3.5 mm. When the deformation amount is smaller than 2.5 mm, the hardness is too high and the shot feeling and controllability may be deteriorated. On the other hand, when the deformation amount is larger than 3.7 mm, the hardness is too low and the resilience performance may be deteriorated. is there.

[0042]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" described in Examples and Comparative Examples are "parts by weight",
“%” Indicates “% by weight”.

(Preparation of Cores) The compositions and the rubber compositions shown in Table 1 were mixed and heated at 157 ° C. for 30 minutes to prepare spherical cores 1 to 6. Table 1 shows the amount of compressive deformation and the coefficient of restitution of these cores.

The amount of compressive deformation of the core refers to the amount of deformation of the core when a load from an initial load of 10 kg to a final load of 130 kg is applied, and the coefficient of restitution is measured using an R & A initial speed measuring machine to measure a metal cylinder at 40 m / s. The core speed at the time of collision with the core at the speed is measured and calculated from the core speed.

[0045]

[Table 1]

In the table, "base rubber" means cis-1,4-
Polybutadiene ("BR-18" manufactured by Nippon Synthetic Rubber Co., Ltd.),
“Organic sulfur compound” is diphenyl disulfide, and “co-crosslinking initiator” is dicumyl peroxide.

(Preparation of cover composition) The compositions and the amounts of the cover compositions shown in Table 2 were mixed, kneaded with a twin screw extruder, and pelletized with a pelletizer (covers 1 to 10). ) Got. Shore D of these covers
Table 2 shows the hardness and the flexural rigidity.

The measurement of the Shore D hardness and the flexural rigidity of the cover were performed by the above-described methods.

[0049]

[Table 2]

Here, "Himilan 1555" is a sodium ion neutralized ethylene / methacrylic acid copolymer ionomer resin manufactured by Mitsui Dupont Polychemicals, and "Himilan 1557" is a zinc ion neutralized type manufactured by Mitsui Dupont Polychemicals. Ethylene / methacrylic acid copolymer ionomer resin, “Himilan 1605” is a sodium ion neutralized ethylene / methacrylic acid copolymer ionomer resin manufactured by DuPont Mitsui Polychemicals, and “Himilan 1706” is zinc manufactured by DuPont Mitsui Polychemicals. Ion neutralized ethylene / methacrylic acid copolymer ionomer resin, "Himilan 1855" is a zinc ion neutralized ethylene / methacrylic acid / isobutyl acrylate terpolymer ionomer resin manufactured by DuPont Mitsui Polychemicals, "Sari""8945" is a sodium ion neutralized ethylene / methacrylic acid copolymer ionomer resin manufactured by DuPont. "Surlyn 9945" is a zinc ion neutralized ethylene / methacrylic acid copolymer ionomer resin manufactured by DuPont. "Surlyn AD8542". Is a magnesium ion neutralized ethylene / methacrylic acid terpolymer ionomer resin manufactured by DuPont;
"533" is a polyamide-based thermoplastic elastomer resin manufactured by Toray Industries, Ltd., and "Epofriend A1010" is a block copolymer having an SBS structure containing an epoxy group-containing polybutadiene block manufactured by Daicel Chemical Industries.

(Production of Golf Ball) A cover composition (covers 1 to 10) was injection-molded on the surfaces of the cores 1 to 6 prepared above to form covers. Next, deburring, paint pretreatment, and painting were performed to obtain a diameter of 42.7 mm and a weight of 4
A 5.4 g golf ball was produced. Tables 3 and 4 show the combinations of the core and the cover and the following characteristics of the golf ball.

(Compression Deformation of Golf Ball) The amount of deformation (mm) of the golf ball when a load of 10 kgf of initial load to 130 kgf of final load is applied to the golf ball.

(Flying distance) A No. 1 wood club was attached to a swing robot manufactured by True Temper, and a golf ball was hit at a head speed of 45 m / s to measure a distance to a falling point.

(Feeling of hitting ball) An actual hitting test was performed by 10 professional golfers, and evaluated by the following criteria. ：: 8 to 10 players answered that the shot feeling was good. Δ: 5 to 7 players answered that the shot feeling was good. ×: 0 to 4 players answered that the shot feeling was good.

(Controllability) A 30-yard approach with a sand wedge was carried out by 10 professional golfers, and evaluated according to the following criteria. ：: 6 to 10 persons answered that the controllability was good. X: 0 to 5 persons answered that the controllability was good.

(Finish Appearance) When the burr formed on the mold mating surface after molding and the entire surface of the golf ball were polished, the surface condition of the polished portion was visually evaluated according to the following criteria. ：: Smooth surface state without roughness (Sakura) ×: Rough (Sakura)

[0057]

[Table 3]

[0058]

[Table 4]

The golf balls of Examples 1 to 4 according to the present invention showed satisfactory results in all of the flight distance, shot feeling, and controllability. On the other hand, in the golf ball of Comparative Example 1, the cover composition was too soft because the amount of the polyamide thermoplastic elastomer in the cover composition was too large, so that the shot feeling was poor and the flight distance was poor, being 202 m. In the golf balls of Comparative Examples 2 and 4, the epoxidized diene-based block copolymer or the polyamide-based thermoplastic elastomer was not included in the cover composition, so that the resilience performance was reduced and the flight distance was 206 m or 205 m. It was a bad result. In the golf ball of Comparative Example 3, since the cover composition was only a binary copolymer ionomer resin, the cover was too hard, the impact upon impact was large, and the controllability was poor. In the golf ball of Comparative Example 5, since the amount of the terpolymer ionomer resin in the cover composition was large, the bending rigidity was reduced and the flight distance was 202.
m was short. The golf ball of Comparative Example 6 did not contain the terpolymer ionomer resin in the cover composition and had poor compatibility between the binary copolymer ionomer resin and other elastomer resins. Its own resilience fell and the flight distance could not be extended. The shot feeling was not good either. In the golf ball of Comparative Example 7, since the amount of the binary copolymer-based ionomer resin in the cover composition was small and the amount of the epoxidized diene-based block copolymer was large, the flexural rigidity was low compared to the cover hardness, and the shot feeling was low. It was heavy and the flight distance did not increase. In the golf ball of Comparative Example 8, since the amount of zinc acrylate contained in the core composition was small, the core was soft, the core deformation was large at the time of hitting, the shot feeling was heavy, and the flight distance was not extended to 204 m. Comparative Example 9
In the golf ball of No. 1, since the organic composition was not contained in the core composition, the resilience performance of the core was lowered and the flight distance was not extended. In the golf ball of Comparative Example 10, since the amount of zinc acrylate in the core composition was large, the core was too hard and the impact upon impact was large.

Further, in the golf balls of Comparative Examples 1, 2, 4, and 7, roughening (crackling) occurred in the polished portion, and the finished appearance was not good. In the golf ball of Comparative Example 1, the polyamide-based thermoplastic elastomer resin and the ionomer resin were originally poorly compatible and had a high content of the polyamide-based thermoplastic elastomer resin. is there. In the golf ball of Comparative Example 2, the epoxidized diene-based block copolymer, which also functions as a dispersant, was not contained in the cover composition, so that the dispersion was poor and rust was generated.

The epoxidized diene-based block copolymer is
As such, it has good compatibility with the ionomer resin, but the epoxy group of the copolymer and the carboxyl group of the ionomer resin are liable to react with each other. appear. In the golf ball of Comparative Example 4, rust occurred for this reason. In the golf ball of Comparative Example 7, the amount of epoxy groups was too large, the dispersion was poor, and rust was generated.

On the other hand, in the golf balls of Examples 1 to 4,
An ionomer resin, a polyamide-based thermoplastic elastomer resin, and an epoxidized diene-based block copolymer are blended in an appropriate amount, respectively, and the compatibility is improved by the block copolymer, and the reaction between the block copolymer and the ionomer resin. Did not occur, good dispersion was obtained, and no rust was formed.

[0063]

According to the solid golf ball of the present invention, the core is formed by the rubber composition containing the specific composition in a specific amount, and the cover is formed by the resin composition containing the specific composition in a specific amount. Thus, it was possible to improve the feel at impact, the controllability, and the finished appearance while maintaining the excellent flight performance and rebound performance originally possessed by the solid golf ball.

Claims (4)

[Claims] 1. A solid golf ball having a core and a cover, wherein the core contains 20 to 40 parts by weight of a metal salt of an unsaturated carboxylic acid and 0.05 to 0.05 parts by weight of an organic sulfur compound based on 100 parts by weight of a base rubber. The cover is formed of a rubber composition containing 0.3 to 3.0 parts by weight of a co-crosslinking initiator and 50 to 90 parts by weight of a binary copolymer ionomer. A resin composition containing 5 to 30 parts by weight of a source copolymer ionomer, 1 to 20 parts by weight of a polyamide-based thermoplastic elastomer resin, and 1 to 15 parts by weight of an epoxidized diene-based block copolymer A solid golf ball characterized by the following. 2. The solid golf ball according to claim 1, wherein an amount of deformation of the core when a load of 10 kg to 130 kg is applied is in a range of 3.0 to 4.5 mm. 3. The cover has a flexural rigidity of 1,300.
3. The solid golf ball according to claim 1, wherein the hardness is in the range of 3,000 kg / cm ² and the Shore D hardness is in the range of 56 to 68. 4. 4. The amount of deformation when a load of 10 kg to 130 kg is applied is in the range of 2.5 to 3.7 mm.
4. The solid golf ball according to any one of claims 1 to 3.