JP3090875B2 - Solid golf ball - Google Patents

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 comprising a hollow core and a cover layer. More specifically, the present invention provides a golf ball having a good feel at impact, a large moment of inertia, a large launch angle at impact, The present invention relates to a golf ball having an increased flight distance.

[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 solid two-piece ball, and is composed of a core made 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 at the center is wound with a rubber thread winding,
It is covered with a cover of a 2 mm thick ionomer resin or balata. Compared to thread-wound golf balls, the two-piece solid golf ball has a longer flight distance due to its higher durability and ball speed when hit,
It has excellent flight characteristics and is used by many golfers, especially amateur golfers. On the other hand, the two-piece solid golf ball has a problem that the feel when hit is hard.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional two-piece solid golf ball, and achieves excellent hitting performance without deteriorating the excellent flight performance characteristic of the two-piece solid golf ball. It is an object of the present invention to provide a solid golf ball with improved feeling at the time.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that a hollow core comprising a hollow portion (1) having a diameter of 5 to 30 mm and a hollow core outer layer portion (2). By using, the feeling at the time of impact is improved, the moment of inertia is increased, the launch angle is large, the spin amount immediately after launch is small, and the spin decay rate between the ball rising and falling is It has been found that the distance can be increased by making the distance smaller, and based on this, the present invention has been completed.

When a golf ball is hit with a golf club, a spin occurs in the ball, and the spin acts on the flight curve of the ball in a direction normal to the flight curve. As for the force, a negative force acts on the ball with respect to the ball traveling direction, so that a large ball speed immediately after hitting is reduced by the lift. On the other hand, when the ball descends after passing the highest point of the flight curve, the lift due to the spin acts as a positive force in the traveling direction with the horizontal component, so the lift when the ball descends is It is preferable that the distance is large to increase the flight distance. Therefore, in order to increase the ball flight distance, it is preferable that the spin amount when the ball rises immediately after hitting is small and the spin amount when the ball descends is large. For that purpose, it is more preferable that the moment of inertia of the ball is large.

That is, the present invention comprises a hollow core and a cover layer (3) formed on the core, wherein the hollow core has a diameter of 10 to 3 mm.
Hollow part having 0 mm (1) and hollow core outer layer other than the hollow part
In the solid golf ball of (2), the hollow core outer layer portion is based on 100 parts by weight of the base rubber, and 25 to 45 parts by weight of a metal salt of an unsaturated carboxylic acid, and 0.5 to 3.0 parts by weight of an organic peroxide. The present invention relates to a solid golf ball comprising a vulcanized molded product of a rubber composition containing 10 to 110 parts by weight of a material, and more preferably comprising a high specific gravity metal powder in the filler.

Hereinafter, the present invention will be described in more detail. The golf ball of the present invention comprises a hollow portion (1) and a hollow core outer layer portion (2).
And a cover layer (3) formed on the hollow core.
Consisting of The larger the diameter of this hollow core hollow part,
Although a golf ball having a large moment of inertia can be obtained, the diameter of the hollow portion is 10 to 30 mm because the vulcanized molded product layer of the rubber composition having rebound resilience in the core is reduced.
Is preferably within the range. If it is larger than 30 mm, it is necessary to use a large amount of filler for adjusting the specific gravity in the outer layer of the hollow core, and the rebound is too low. If it is smaller than 10 mm, the hollow effect cannot be seen. Since the diameter of the hollow core is 37 to 39.5 mm, the thickness of the outer layer of the hollow core is 3.5 to 14.75 mm.

The hollow core outer layer is obtained by heating, pressing and molding a rubber composition containing a base rubber, a metal salt of an unsaturated carboxylic acid, an organic peroxide, a filler and the like.

As the base rubber, natural rubber and / or synthetic rubber conventionally used for solid golf balls are used, and particularly have a cis-1,4-structure of at least 40%, preferably at least 80%. So-called high cis polybutadiene rubber is preferred, and if desired, natural rubber, polyisoprene rubber, styrene polybutadiene rubber, EP
You may mix DM etc.

The metal salts of unsaturated carboxylic acids act as co-crosslinking agents, especially zinc, magnesium salts and the like of α, β-unsaturated carboxylic acids having 3 to 8 carbon atoms such as acrylic acid or methacrylic acid. Although a monovalent or divalent metal salt is mentioned, zinc acrylate which gives high repulsion is suitable. The compounding amount is preferably 25 to 45 parts by weight based on 100 parts by weight of the base rubber. If the amount is more than 45 parts by weight, it becomes too hard and the feeling becomes poor, and if it is less than 25 parts by weight, rebound becomes poor and the flight distance decreases.

The organic peroxide acts as a cross-linking or curing agent and includes, for example, dicumyl peroxide or t-butyl peroxide, with dicumyl peroxide being preferred. The compounding amount is 0.5 to 100 parts by weight of the base rubber.
Preferably it is 3.03.0 parts by weight. If it is less than 0.5 parts by weight, it becomes too soft and rebound becomes poor, resulting in a reduced flight distance.
If it exceeds 3.0 parts by weight, it will be too hard and the feeling will be poor.

The filler may be any one as long as it is usually compounded in the core of a golf ball. For example, an inorganic salt (specifically,
Zinc oxide, barium sulfate, calcium carbonate), high specific gravity metal powder (for example, tungsten powder, molybdenum powder, etc.) and mixtures thereof. Since the weight of the hollow core used in the present invention tends to be less than that of a normal solid core, it is preferable to use a mixture of an inorganic salt and a high specific gravity metal powder. The compounding amount is preferably 10 to 110 parts by weight based on 100 parts by weight of the base rubber. If the amount is less than 10 parts by weight, it is difficult to adjust the weight, and if it exceeds 110 parts by weight, the rebound is too low.

The hollow core can be obtained by vulcanizing and molding a rubber composition containing the above-mentioned components. However, it is necessary to devise a hollow core. For example, two semi-vulcanized hemispherical shells may be formed and combined to perform post-vulcanization. In this case, the vulcanization conditions during semi-vulcanization are 10-
The conditions for the post-vulcanization are 140 to 165 ° C. for 10 to 40 minutes.

The hollow core obtained by vulcanization preferably has a JIS C hardness (equivalent to Shore C hardness) of 50 to 90, more preferably 60 to 85. If it is less than 50, the core is too soft and the rebound decreases. If it exceeds 90, on the other hand, it becomes too hard, and the feeling decreases.

The specific gravity of the outer layer portion of the hollow core must be slightly higher than the specific gravity of the core of a conventional golf ball.
This is because the hollow portion has a high specific gravity to compensate for the weight of the hollow portion. The specific gravity of conventional golf balls is 1.
0 to 1.17, the specific gravity of the hollow core of the present application is 1.1 to 2.0.
It is.

Next, a cover layer is coated on the hollow core. The cover can be formed of an ionomer resin commonly used as a cover material for a solid golf ball, and a small amount of another resin may be added.

The cover composition may contain an additive such as titanium dioxide for coloring and other additives such as an ultraviolet absorber, a light stabilizer, a fluorescent material or a fluorescent brightener, and the like. Although it may be contained within a range that does not impair the desired properties of the ball cover, the amount of the coloring agent is usually preferably 0.1 to 0.5 part by weight.

The cover layer of the present invention is formed by a generally known method used for forming a cover of a golf ball, for example, injection molding, press molding or the like. The thickness of the cover layer is preferably 1 to 3 mm.
Many depressions called dimples are formed on the surface.
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.

According to the present invention, there is provided a golf ball having a good feel at impact, a large moment of inertia, a large launch angle at impact, and an increased flight distance.

[0020]

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

Preparation of Hollow Core The rubber composition shown in Table 1 was placed on both sides of a half-break mold for core pressing, and a hemispherical convex core mold having a hollow center diameter was sandwiched between the molds, and preformed at 155 ° C. for 10 minutes. Then, by removing the core mold and vulcanizing at 155 ° C for 30 minutes, the diameter is 39m.
m hollow cores A to E were obtained.

[0022]

[Table 1] (parts by weight) Type ABCD BR-18 (Note 1) 100 100 100 100 100 100 Zinc acrylate 37 37 37 37 37 37 Zinc oxide 5 5 22.6 5 52 15.2 Tungsten 12.3 14.8-37.9 106.0 − Anti-aging agent (Note 2) 0.5 0.5 0.5 0.5 0.5 0.5 Dicumyl peroxide 1 1 1 1 1 1 Hollow center diameter (mm) 5 10 10 20 30 0 Core weight (g) 36.1 36.1 36.1 36.1 36.1 36.1

Examples 1-4, Comparative Examples 1-2 Cover Layer A cover layer was formed by coating a cover composition having the composition shown in Table 2 on the hollow cores AE obtained as described above. A paint solid was applied to produce a hollow solid golf ball having a diameter of 42.7 mm.

[Table 2]

(Note 1) High-cis-1,4-polybutadiene manufactured by Nippon Synthetic Rubber Co., Ltd. (Note 2) Yoshitomi Pharmaceutical (Note 3) Ionomer resin manufactured by Mitsui Polychemicals

Each of the obtained golf balls was evaluated for flight performance by a driver (Wood No. 1 club) and feeling when hit, and the results are shown in Table 3.
The test method was performed as follows. (Test method) Launch angle, spin amount and flight distance A driver is attached to a swing robot manufactured by True Temper, and a golf ball is hit at a head speed of 45 m / sec.
The launch angle (ballistic height) is measured, the distance to the drop point (carry) is measured as the flight distance, and the shot amount of the golf ball is continuously photographed to determine the spin amount. Feeling at the time of impact Evaluate by hitting with a driver by a professional golfer.
The evaluation criteria are as follows. Evaluation criteria ◎… very soft and good ○… soft and good ×… hard and bad

[0026]

[Table 3]

From the above results, Examples 1 to 4 of the present invention have a better feel at impact, a larger launch angle at impact, and a longer flight distance than the solid golf balls of Comparative Examples 1 and 2. It was found to be large.

[0028]

The solid golf ball of the present invention has a diameter
By using a hollow core having a hollow portion having a length of 10 to 30 mm and a hollow core outer layer portion other than the hollow portion, the feeling at impact is improved, the moment of inertia is increased, and the launch angle at impact is increased. And the flight distance is increased.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hollow part 2 ... Hollow core outer layer part 3 ... Cover layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-323098 (JP, A) JP-A-60-241465 (JP, A) JP-A-49-103722 (JP, A) 63354 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A63B 37/00

Claims (2)

(57) [Claims] 1. A hollow core comprising a hollow core and a cover layer formed on the core, wherein the hollow core has a diameter of 10 to 30 mm and a hollow core outer layer other than the hollow portion. ), The hollow core outer layer portion is based on 100 parts by weight of the base rubber, and the metal salt 25 of the unsaturated carboxylic acid is used.
~ 45 parts by weight, organic peroxide 0.5 ~ 3.0 parts by weight, filler 10 ~
A solid golf ball comprising a vulcanized molded product of a rubber composition containing 110 parts by weight. 2. The solid golf ball according to claim 1, wherein the filler contains a high specific gravity metal powder.