JPH09122273A - Solid golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball which improves in feeling of drive and controllability of approach without impairing carry or durability characterizing golf balls, particularly, solid balls. SOLUTION: In a golf ball consisting of a core 1 and a cover formed on the core and having a double-layer cover structure with the cover consisting of the inside cover layer 2 and outside cover layer 3, a solid golf ball uses the rubber composition of the core 1 containing 0.05-6 pts.wt. of organic sulfide compound to 100 pts.wt. of base material rubber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf ball, and more particularly to a golf ball having improved feel at hitting and controllability in approach without impairing the flight distance and durability which are features of solid golf balls.

[0002]

2. Description of the Related Art In the prior art, there are mainly two types of golf balls. One is a solid golf ball such as a two-piece ball, which is composed of a core formed of an integrally molded rubber member and a thermoplastic resin cover such as an ionomer resin coated on the core. The other is a thread-wound golf ball, in which a solid or liquid core is wound with a rubber thread winding and then covered with a cover made of an ionomer resin or balata having a thickness of 1 to 2 mm. The solid golf ball has a long flight distance and excellent flight characteristics because of its high durability and high ball speed upon hitting, as compared with the thread wound golf ball. On the other hand, solid golf balls have a hard feel when hit, a high ball speed when hit, and a small contact area with the hitting surface of the golf club, which makes spin less likely to occur and controllability of the approach. There was a problem of lacking.

In order to solve this problem, it has been proposed to use a cover made of a soft material to give flexibility to the outer portion of the ball. However, the impact resilience of the ball is inferior to that of the conventional cover, so the flight distance, which is a characteristic of the two-piece ball, is reduced.

In order to solve such a problem, a two-layer cover golf ball has been proposed in which the cover layer has a two-layer structure and different cover materials are used for the respective layers. For example, in JP-A-4-244174, a thermoplastic material containing an amide block copolymer is used for the inner cover layer, and a thermoplastic resin is used for the outer cover layer. However, in this golf ball, a block copolymer having a low rigidity is used for the inner cover layer, which causes a reduction in repulsion and is not sufficient in terms of increasing the flight distance. In addition, Japanese Unexamined Patent Publication
According to Japanese Patent No. 343718, in a golf ball having a two-layer cover structure, a cover made of a hard high-acid ionomer resin is used for the inner cover layer to increase the flight distance. Even if a hard (high rigidity) high acid ionomer resin is used for the inner cover layer, there is a limit to increase the ball speed because the outer cover layer is soft, and the inner cover layer is hardened to increase the ball speed. I had to do it.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that the core contains 0.05 to 5 parts by weight of an organic sulfide compound with respect to 100 parts by weight of a base rubber. It has been found that the use of the rubber composition increases the impact resilience of the core and thereby the impact resilience of the ball.

The present invention will be described in more detail below. In the golf ball of the present invention, a cover layer (2 and 3) having a two-layer structure is formed on a core (1). The core is obtained by heating, pressing and molding a rubber composition containing a base rubber, a crosslinking agent, a co-crosslinking agent, an organic sulfide compound and the like.

As the base rubber, natural rubber and / or synthetic rubber conventionally used for solid golf balls is used, and in particular, cis-containing 40% or more cis-structure.
1,4-polybutadiene is preferred, if desired natural rubber,
Polyisoprene rubber, styrene-butadiene rubber, EP
You may mix DM etc.

Examples of crosslinking agents include organic peroxides such as dicumyl peroxide or t-butyl peroxide, with dicumyl peroxide being preferred.
The compounding amount is 0.3 to 5.0 parts by weight, preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the base rubber.

As the co-crosslinking agent, those which have been used for conventional solid golf balls can be used. Examples thereof include metal salts of unsaturated fatty acids, particularly monovalent or divalent metal salts having 3 to 8 carbon atoms such as acrylic acid or methacrylic acid, and zinc acrylate having high repulsion property is preferable. The compounding amount is preferably 10 to 40 parts by weight with respect to 100 parts by weight of the base rubber. If it is more than 40 parts by weight, it becomes too hard and the feeling becomes bad, and if it is less than 10 parts by weight, the repulsion becomes worse.

The rubber composition used for producing the solid golf ball of the present invention contains an organic sulfide compound in addition to the above components. Examples of the organic sulfide compound include polysulfides having a sulfur number of 2 to 4, such as diphenyl polysulfide, dibenzyl polysulfide, dibenzoyl polysulfide, dibenzothiazoyl polysulfide and dithiobenzoyl polysulfide, and a compound represented by the formula: (In the formula, n is an integer of 1 to 4, and R and R ′ are C
H _3, a _{C 2 H 5, C 4 H} 9, C 6 H 5 or ethyleneoxy. ) Tetraalkyl thiuram sulfide as shown in () is illustrated. These may be used alone or in combination of two or more. The compounding amount is 0.05 to 5 parts by weight, particularly preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the base rubber.
Parts by weight. If the amount is less than 0.05 parts by weight, the effect of the organic sulfide cannot be exhibited, and if the amount is more than 5 parts by weight, the effect is not improved.

Further, the rubber composition is appropriately blended with an inert filler such as zinc oxide, barium sulfate and calcium carbonate, an antioxidant and other components which can be usually used for producing a solid golf ball core. Good.

The core obtained by heat-molding the above-mentioned composition by using the method and conditions usually used for a solid core preferably has a diameter of 32 to 37.5 mm. Further, in order to obtain a desired feeling, the amount of deformation when a load of 10 kg to 130 kg is applied is preferably 3.5 to 6.0 mm, and if it is smaller than 3.5 mm, it becomes too hard, and if it is larger than 6.0 mm, it becomes too soft.

Next, the core (1) is covered with an inner cover (2) and an outer cover (3). As the material for the inner cover, ionomer, polyester, nylon or the like may be used alone or in combination of two or more, but the bending rigidity thereof is 3,000 to 7,000 from the viewpoint of feeling and flight characteristics.
It is preferably kgf / cm ² and its thickness is preferably 1.0 to 3.0 mm.

As the outer cover material, those usually used for conventional two-piece golf ball covers, for example, ionomer resins may be used alone or in combination.
In terms of feel and flight characteristics, the stiffness modulus is 1,000~2,800kgf / cm ^2, its thickness is 1.0~3.0mm
It is desirable that Total cover thickness is 2.0 to 5.0
mm is preferred.

The cover layer of the present invention (inner cover layer
(2) and the outer cover layer (3)), for example, a coloring agent such as titanium oxide and other additives such as an ultraviolet absorber, a light stabilizer and a fluorescent material or a brightening agent, golf ball cover It may be contained in a range that does not impair the desired characteristics of

The cover layer of the present invention is formed by a generally known method used for forming a cover of a golf ball, such as injection molding or press molding. First, the inner cover (2) is manufactured by coating the core (1) and then the outer cover (3). When the outer cover (3) is covered, a large number of depressions called dimples are usually formed on the surface. Both the outer and inner cover layers have a thickness of 1.
The range of 0 to 2.3 mm is preferable. The golf ball of the present invention is usually coated with paint and put on the market in order to enhance aesthetic appearance and commercial value.

In the present invention, a golf ball having a soft and excellent repulsion, a soft feeling and excellent flight characteristics is provided by blending an organic sulfide compound.

[0018]

The present invention will be described in more detail with reference to examples.
However, the present invention is not limited to these examples.

(Compounding) (a) Core blending (the following core blending was kneaded and then heat-molded to obtain a spherical core having a diameter of 35.6 mmφ).

[Table 1] Example ratio Comparative example type 1 2 3 4 5 1 2 3 BR-01 (Note 1) 100 100 100 100 100 100 100-Zinc acrylate 26 28 26 26 26 26 24 24-Zinc oxide 30 29 30 30 30 30 31-Dicumyl peroxide 2.0 2.0 2.0 2.0 2.0 2.0 2.0-Anti-aging agent (Note 2) 0.5 0.5 0.5 0.5 0.5 0.5 0.5- Diphenyl disulfide 0.5 2.0 0.5 0.5 0.5 --- Vulcanization condition: 150 ° C 25 minutes

(B) Inner cover layer composition (The following cover composition was injection-molded on the above core to form an inner cover layer having a thickness of 1.7 mm.)

[Table 2] Type ABCD High Milan (Note 3) 1605 40 38 High Milan 1706 40 38 50 High Milan AM7317 40 High Milan AM7318 60 Lilsan AMN OD (Note 4) 20 High Milan 1855 50 IOTEC 8000 (Note 5) 50

(C) Outer cover layer composition (The following cover composition was injection-molded on the ball coated with the inner cover to form an outer cover layer having a thickness of 1.9 mm, and at the same time, dimples were also formed.)

[Table 3] Type E FGH Himilan 1652 50 25 30 Himilan 1855 50 25 30 Himilan 1557 50 Himilan 1605 50 Himilan 1706 25 20 Himilan 1707 25 20

(Note 1) Polybutadiene manufactured by Japan Synthetic Rubber Co., Ltd. (Note 2) Yoshitomi Pharmaceutical (Note 3) Ionomer resin manufactured by Mitsui Polychemicals (Note 4) Polyamide elastomer manufactured by Toray Industries (Note 5) Ionomer manufactured by Exxon resin

(Test results)

[Table 4] Actual example ratio Comparative example Test item 1 2 3 4 5 1 2 3 (Note 1) Inner cover layer A B A C C D A A Bending rigidity (kgf / cm ² ) 4400 5100 4400 3000 4200 4400 4400- Outer cover layer E GH H EF- Flexural rigidity (kgf / cm ² ) 1300 1300 2800 2600 2600 1300 3100- W # 1 carry (yard) 221 219 222 219 221 217 216 216 Feeling ○ ○ ○ ○ ○ × × △ Approach ○ ○ ○ ○ ○ △ × △ Controllability (Note 1) Commercial two-piece ball manufactured by Sumitomo Rubber Industries, Ltd. Compared with the comparative example, the carry in W # 1 is equal to or more than that of the comparative example. The result is excellent in control of feeling and approach.

(Test Method) (a) Carry Golf club W of a golf ball manufactured by using the core, the inner cover layer and the outer cover layer having the above-mentioned composition.
The carry was measured with # 1 (head speed: 45 m / sec) (device name: swing robot manufactured by Trutemper Co., Ltd.). (b) Feeling and controllability of approach We conducted a questionnaire to 10 professional and top amateur golfers, and evaluated it as follows based on the number of people who answered that both items were good. ○… 8-10 people △… 4-7 people ×… 0-3 people

[0025]

EFFECTS OF THE INVENTION The solid golf ball of the present invention, by using the core molded by the above-mentioned composition, can suppress the reduction of the repulsion even if the hardness of the core is reduced, and the durability is improved by the multi-layer cover. It improves the feel when hit and the controllability when approaching.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a golf ball of the present invention.

[Explanation of symbols]

 1 ... Core 2 ... Inner cover layer 3 ... Outer cover layer

Claims (4)

[Claims] 1. A core (1) and a cover formed on the core, the cover comprising an inner cover layer (2) and an outer cover layer.
In the golf ball having the two-layer cover structure of (3),
A solid golf ball using a rubber composition in which the core (1) contains 0.05 to 5 parts by weight of an organic sulfide compound with respect to 100 parts by weight of a base rubber. 2. The golf ball according to claim 1, wherein the amount of deformation of the core under a load of 10 to 130 kg is 3.5 to 6.0 mm. 3. The bending rigidity of the inner cover layer (2) is 3,0.
The golf ball according to claim 1, which has a range of 00 to 7,000 kgf / cm ² . 4. The flexural rigidity of the outer cover layer (3) is 1,0.
The golf ball according to claim 1, which has a range of 00 to 2,800 kgf / cm ² .