JPH11244418A - One piece solid golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-piece solid golf ball having excellent durability and excellent carry performance. SOLUTION: The ball hardness distribution of the one-piece solid golf ball 1 obtd. by crosslinking a rubber compsn. contg. at least base material rubber, an inorg. filler, a crosslinking monomer and a crosslinking initiator is so determined that the hardness in the hardness designation by a JIS-C type hardness meter is 56 to 69 at the center, 63 to 73 on the side outer by 5 mm than the center, 67 to 76 on the side outer by 100 mm from the center, 72 to 80 on the side outer by 15 mm from the center, 73 to 83 on the surface and increases gradually nearer the outer side than the center. The ball is so formed that the compression deformation rate when a final load 130 kg is applied on the ball from the state of applying an initial load 10 kg on the ball attains 2.4 mm to 2.9 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a one-piece solid golf ball, and more particularly, to a one-piece solid golf ball having excellent durability and flight distance performance.

[0002]

2. Description of the Related Art Generally, golf balls have two uses depending on their use.
They are roughly classified into species. One of them is a round golf ball usually used in a golf course, and the other is a practice golf ball used in a driving range.

The performance required of the above two types of golf balls is not the same, although it is the same golf ball. That is, the performance required for a round golf ball is a good shot feeling, a shot with an excellent flight distance or elongation, and a certain degree of durability. However, when such a golf ball for a round is used for practice, although good hit feeling and flight distance performance are maintained, it is extremely durable as a golf ball for a driving range that is repeatedly hit hundreds of times. Will be bad. Therefore, a practice golf ball having excellent durability is used in a practice field.

The practice golf balls also have low rebound, low trajectory, high trajectory, water ball, etc. in addition to the standard ball, depending on the size of each practice area, the height of the net, and the like. Although there are various golf balls such as a one-piece golf ball and a two-piece golf ball in terms of structure, a one-piece solid golf ball, which is a standard ball, is most frequently used.

[0005]

However, recently, even in this one-piece solid golf ball, too much emphasis has been placed on durability, and the flight distance performance has been reduced. Tend to do so.

[0006] It is difficult to use a high quality material to improve the cost for a one-piece solid golf ball that requires low cost. For this reason, at present, a one-piece solid golf ball having satisfactory performance in both durability and flight distance performance has not been obtained.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a one-piece solid golf ball having excellent durability and flight distance performance.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have focused on the hardness distribution of a one-piece solid golf ball, and have made various studies on the hardness distribution, and have also studied on the amount of compressive deformation. As a result, durability is excellent,
The inventors have found that a one-piece solid golf ball having excellent flight distance performance can be obtained, and have completed the present invention.

That is, the present invention relates to a one-piece solid golf ball obtained by crosslinking a rubber composition containing at least a base rubber, an inorganic filler, a crosslinking agent monomer and a crosslinking initiator, using a JIS-C type hardness meter. The hardness is 56-66 at the center, 63-73 at 5 mm outside the center, and 6 at 10 mm outside the center.
7-76, 72-8 at 15mm outside center
0, having a hardness distribution of 73-83 on the surface and increasing in hardness from the center to the outside, and a final load of 130 kg from a state where an initial load of 10 kg is applied to the obtained ball
The present invention relates to a one-piece solid golf ball, wherein the amount of compressive deformation up to the time of application is 2.4 to 2.9 mm.

Although the one-piece solid golf ball of the present invention is a solid golf ball having an integral structure, the one-piece solid golf ball has a performance as if it were a multi-layered ball due to having the hardness distribution as described above. The launch angle is increased and the flight distance is improved without too much impact, and the hardness of the center of the ball is lower than that of the outside, so the center of the ball is softer than the outside, so that the impact on the ball at the center part They can be absorbed, so that a soft touch feeling and excellent durability can be obtained. Therefore, the one-piece solid golf ball of the present invention has excellent durability and excellent flight distance performance.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as the base rubber, any suitable natural rubber and / or synthetic rubber conventionally used for one-piece solid golf balls can be used. %, Especially preferred is cis-1,4-polybutadiene,
If desired, natural rubber, polyisoprene, styrene-butadiene rubber, and the like can be appropriately blended with the above polybutadiene.

As the inorganic filler, for example, zinc oxide, silicon oxide, calcium carbonate, aluminum silicate and the like are used. The main role of these inorganic fillers is to increase the hardness and impact strength, improve the durability of the ball, and improve the feel at impact and the impact sound, but in some cases α, such as acrylic acid and methacrylic acid, It reacts with β-monoethylenically unsaturated carboxylic acids to form metal salts of these acids, and also has a role of allowing the rubber composition to crosslink as a crosslinkable monomer. The amount of the inorganic filler to be compounded varies depending on the specific gravity, size, ball weight standard and the like of the ball, and is not particularly limited. However, usually, 10 to 60 parts by weight is preferable for 100 parts by weight of the base rubber.

The crosslinkable monomer is used to crosslink the rubber composition to exhibit rebound resilience and the like, and to impart hardness, durability, favorable hit feeling, hitting sound and the like to the golf ball. Examples of the functional monomer include, for example, α, β-monoethylenically unsaturated carboxylic acid such as methacrylic acid and acrylic acid or a metal salt thereof, polyfunctional methacrylic acid ester such as trimethylpropane trimethacrylate, and trimethylolpropane triacrylate. Functional acrylic acid esters and the like are used, and the amount of these crosslinkable monomers is not particularly limited, but is preferably 19 to 29 parts by weight, more preferably 22 to 26 parts by weight based on 100 parts by weight of the base rubber. Parts are preferred. If the amount of the crosslinking monomer is less than 19 parts by weight based on 100 parts by weight of the base rubber, the hardness of the ball tends to be insufficient. If the amount is more than 29 parts by weight, the ball becomes too hard and the ball is hit. It tends to impair the feeling of time.

The crosslinking initiator is used to initiate polymerization of the crosslinking monomer to crosslink the rubber composition. Examples of such a crosslinking initiator include dicumyl peroxide, 2,2-di (tert-
Peroxides such as butylperoxy) butane and tert-butyl perbenzoate are used, and the amount of these crosslinking initiators is not particularly limited.
0.1 to 3 parts by weight, preferably 0.15 to 2 parts by weight, per 100 parts by weight.

In the present invention, the rubber composition for producing a one-piece solid golf ball includes an antioxidant and other additives in addition to the base rubber, inorganic filler, crosslinkable monomer, and crosslinking initiator. May be appropriately compounded.

In the present invention, the hardness distribution of the ball is JIS-
The hardness at the center is 56 to 66 as measured by a C-type hardness meter.
63-73 at a location 5 mm outside the center, 67-76 at a location 10 mm outside the center, 15 m from the center
The cross-linking conditions are appropriately adjusted so that m is 72 to 80 on the outside, the surface is 73 to 83, and the hardness increases from the center to the outside. Adjustment of such cross-linking conditions is adjustment of the cross-linking temperature and time. Can be achieved by:
Crosslinking is carried out by heating under pressure. At that time, the temperature and time may be appropriately set. In addition to the case of crosslinking at a constant temperature, if necessary, the temperature may be changed in two or more steps. Step crosslinking can also be employed.

The hardness is measured with a JIS-C type hardness meter according to JIS-K-6301. The hardness tester is JI
Any type of hardness tester may be used as long as it is an SC type hardness meter, but in the present invention, JIS-C manufactured by Kobunshi Keiki Co., Ltd.
The hardness was measured using a mold hardness meter. The hardness inside the ball is measured by cutting the ball into two equal parts and measuring the hardness at each position of the hemisphere cut into two equal parts.

In the present invention, the hardness distribution of the ball is defined as J
The hardness is 56-66 in the hardness display by IS-C type hardness tester.
63-73 at a location 5 mm outside the center, 67-76 at a location 10 mm outside the center, 15 m from the center
As described above, the durability and the flight distance performance are improved by increasing the hardness from 72 to 80 on the outer side, from 73 to 83 on the surface, and increasing from the center to the outer side. Is out of the above range, the durability is reduced, or the flight distance performance is reduced, or both the durability and the flight distance performance are reduced, so that the one-piece solid with the desired durability and flight distance performance is excellent. Golf balls cannot be obtained.

The amount of compression deformation of the obtained ball also has a great effect on the feeling at the time of hitting and the flight distance performance. The term “compression deformation amount” as used herein refers to the amount of deformation of the ball from the state in which an initial load of 10 kg is applied to the ball until the final load of 130 kg is applied, and in the present invention, the amount of compression deformation is 2.4 to 2 .9 mm. That is,
When the amount of compressive deformation of the ball is smaller than 2.4 mm, the ball is too hard and the feel at impact is poor, and when the amount of compressive deformation is larger than 2.9 mm, the ball becomes too soft and the flight distance is short. The feeling at the time of hitting worsens as well.

Next, an example of the one-piece solid golf ball of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing one example of a one-piece solid golf ball of the present invention. This one-piece solid golf ball 1 has a rubber containing at least a base rubber, an inorganic filler, a crosslinkable monomer and a crosslinking initiator. It consists of a cross-linked molded product obtained by cross-linking the composition, and has a hardness of 56 to 66 at the center as indicated by a JIS-C hardness tester, 63 to 73 at 5 mm outside the center, and 67 to 73 at 10 mm outside from the center. 76, 72 at 15mm outside center
~ 80, the surface is 73-83, and has a hardness distribution in which the hardness increases as going from the center to the outside, and the amount of compressive deformation from when the initial load of 10 kg is applied to the final load of 130 kg to the ball Is 2.4 to 2.9 mm. In FIG. 1, reference numeral 1a denotes a dimple, and the dimple 1a is provided on the ball surface in an appropriate number and in an appropriate form so that desired or desired characteristics can be obtained. The one-piece solid golf ball is provided with paint or marking on the ball surface as necessary.

[0021]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

Examples 1 to 3 and Comparative Examples 1 to 2 The rubber compositions for producing one-piece solid golf balls were prepared by kneading the components shown in Table 1.

[0023]

[Table 1]

The antioxidant used was 4,4'-thiobis- (6-tert-butyl-3-methylphenol), and the obtained rubber composition was formed into a plug by an extruder. The resulting rubber composition was filled in a mold, and crosslinked under different conditions to produce a one-piece solid golf ball having a diameter of 42.88 mm. Crosslinking conditions (heating temperature and heating time)
Are as shown in Table 2 below.

[0025]

[Table 2]

The hardness distribution, compression deformation, restitution coefficient, flight distance (carry, run, total), back spin amount, launch angle and durability of the obtained one-piece solid golf ball were examined. Table 3 shows the results. The method for measuring the above characteristics is as follows.

Hardness: Measured by a JIS-C type hardness meter according to JIS-K-6301. The hardness was measured at a predetermined position, and Table 3 shows the hardness distribution. The hardness was measured for two balls for each ball, and the average value was displayed.

Amount of compressive deformation: The amount of deformation from the state where an initial load of 10 kg is applied to the ball until the final load of 130 kg is applied is examined. The measurement of the amount of compressive deformation is performed for eight balls for each ball, and the average value is obtained.

Coefficient of restitution: weight 1 due to resilience gun
A 98 g stainless steel cylinder was launched at an initial velocity of 45 m / s, and collided with a ball in front of the cylinder. The velocity of the cylinder and the ball after the collision were measured by two photoelectric tubes, and the coefficient of restitution was calculated from each velocity and weight. I do. The larger the coefficient of restitution, the higher the resilience performance of the ball and the better the flight distance performance. The measurement of the coefficient of restitution is performed for each of eight balls, and the average value is obtained.

Flying distance: The No. 1 wood club was attached to a swing robot manufactured by True Temper, and the ball was hit at a head speed of 45 m / sec in a windless state to carry (to the drop point) and run (to stop from the drop point). And the total (carry + run). The measurement of the flight distance is performed for eight balls for each ball, and the average value is obtained.

Back spin amount: Determined by attaching a No. 1 wood club to a swing robot manufactured by True Temper, hitting the ball at a head speed of 45 m / s, and continuously photographing the mark on the hit ball. The measurement of the backspin amount is performed for each of eight balls, and the average value is obtained.

Launch angle: Determined by attaching a No. 1 wood club to a swing robot manufactured by True Temper, hitting the ball at a head speed of 45 m / s, and continuously photographing the mark on the hit ball. The measurement of the launch angle is performed for eight balls for each ball, and the average value is obtained.

Durability: 4 balls on metal plate with air gun
The ball is hit at a ball speed of 5 m / s, and the number of times until the ball cracks is examined. The durability is measured for each of eight balls, and the average value is determined.

In displaying the hardness distribution in Table 3, “5 mm outside from the center” is simplified and indicated as “5 mm outside”, and “10 mm outside from the center” is simplified and indicated as “10 mm outside”. , "15mm outside center"
Is simplified and indicated as “15 mm outside”.

[0035]

[Table 3]

As shown in Table 3, Examples 1 to 3 had larger flight distances and better flight distance performance than Comparative Examples 1 and 2. This is apparent from the hardness distribution in Table 3,
In Examples 1 to 3, the hardness of the center is low, the hardness of the surface is high, and the outer hard and inner soft type has a hardness distribution, so the resilience performance of the ball is high, and the launch angle is large, This is considered to be due to the fact that the spin amount was reduced and the flight distance was increased. In Examples 1 to 3, since the hardness at the center was low, the feel at the time of hitting was soft, and the shot feeling was excellent.

On the other hand, in Comparative Examples 1 and 2, the hardness of the center is relatively high, and the hardness of the surface is not so high. In particular, the hardness from the position 15 mm outside the center to the surface decreases. A one-piece solid golf ball having such a hardness distribution has a low rebound performance, a small launch angle, a large backspin amount, a short flight distance, and a large flight distance as shown in Table 3. Cannot be obtained. In Comparative Examples 1 and 2, the feel was hard and the shot feeling was poor because the hardness at the center was high.

With respect to durability, Examples 1 to 3
It was almost the same level as Comparative Examples 1 and 2, and no decrease in durability due to the use of the above configuration was observed, and the durability was excellent.

[0039]

As described above, according to the present invention, a one-piece solid golf ball having excellent durability and flight distance performance can be provided. Further, the one-piece solid golf ball of the present invention has excellent durability and flight distance performance as described above, and is particularly suitable as a practice ball.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of a one-piece solid golf ball of the present invention.

[Explanation of symbols]

 1 One-piece solid golf ball

Claims (1)

[Claims] 1. A one-piece solid golf ball obtained by crosslinking a rubber composition containing at least a base rubber, an inorganic filler, a crosslinking monomer and a crosslinking initiator, the center of which is indicated by a hardness indicated by a JIS-C type hardness meter. 56 ~
66, 63-73 at a position 5 mm outside the center, 67-76 at a position 10 mm outside the center, 1
72 to 80 outside 5 mm, 73 to 83 on the surface
And has a hardness distribution in which the hardness increases with increasing distance from the center to the outside, and the amount of compressive deformation from a state where an initial load of 10 kg is applied to a state where a final load of 130 kg is applied to the ball is 2.4 to 2.9 mm. A one-piece solid golf ball, characterized in that: