JPH08322964A - Three-piece solid golf ball - Google Patents

Abstract

PURPOSE: To provide a three-piece solid golf ball which generates sufficient flying distance, gives soft touch of striking, and has high durability. CONSTITUTION: This three-piece solid golf ball is constituted so that a solid core 1 consisting of a nucleus 1a and a sheath 1b is enclosed with a cover 2, wherein (i) the Shore D hardness of the central part of the nucleus 1a is 15-45, and (ii) the Shore D hardness of the range 0-4mm from the surface of the nucleus 1a toward the center is not more than 45, provided that (i)<=(ii), and also it is conditioned that (iii) the Shore D hardness of the inner side of the sheath 1b is not more than 65, and (iv) the Shore D hardness of the range 0-2mm from the surface of the sheath 1b toward the inner side is not less than 40, provided that (ii)<(iii) and (iii)>(iv).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-piece solid golf ball in which a solid core having a two-layer structure is covered with a cover.

[0002]

2. Description of the Related Art Two-piece solid golf balls have a drawback that they have a hard hitting feel, although they have a long flight distance. Therefore, as a solution to this drawback of the two-piece solid golf ball, a three-piece solid golf ball having a two-layer solid core structure has been proposed.

For example, in JP-A-60-241464, a solid core is divided into an inner core and an outer core, and the inner core has a hardness of 50 to 70 (JI).
S-C hardness), outer core hardness 70-90 (JIS
-C hardness) three-piece solid golf balls are disclosed. The inner core is made soft and the outer core is made hard to obtain a soft hitting feel and a sufficient flight distance.

[0004]

In this case, the above three-piece solid golf ball has a soft impact feeling by softening the inner core, but the hardness of the outer core has an effect. Therefore, it is hard to say that the feel when hit is not necessarily soft. Further, this golf ball has a drawback that its durability is considerably lower than that of a two-piece solid golf ball, because the golf ball is largely deformed when hit.

It is an object of the present invention to provide a three-piece solid golf ball which can obtain a sufficient flight distance, has a soft hitting feel, and is highly durable.

[0006]

In order to achieve the above-mentioned object, the present invention provides a three-piece solid golf ball in which a solid core consisting of a core portion and an outer cover thereof is covered with a cover. (1) Shore D hardness of the central part of the core part: 15 to 45, (2) Shore D hardness in the range of 0 to 4 mm from the surface of the core part to the center part: 45 or less, and , (1) ≤ (2), and the jacket of the solid core is (3) Shore D hardness of the inner part of the jacket: 65 or less, (4) From the surface of the jacket toward the inner part. Shore D hardness in the range of 0 to 2 mm: 40 or more, and (2) <(3), (3)>
(4) is a feature.

As shown in FIG. 1, the three-piece solid golf ball of the present invention has a core portion 1a and its outer jacket 1b.
And a cover 2 that covers the solid core 1.

In the core portion 1a of the solid core 1, if the Shore D hardness of the central portion is lower than 15, durability may be poor, and if it is higher than 45, the feel on impact may be poor. Further, 0 to 4 mm from the surface of the core portion 1a toward the central portion.
Even if the Shore D hardness in the range is higher than 45, the feel on impact may be deteriorated. Furthermore, when the hardness of the central portion of the core portion 1a is higher than the hardness of the surface side,
The flight distance is hard to come out.

When the Shore D hardness of the inner portion of the outer cover 1b of the solid core 1 is higher than 65, the feel on impact is deteriorated. In addition, from the surface of the outer cover 1b toward the inner portion 0
If the Shore D hardness in the range of 2 mm is lower than 40, it becomes difficult to carry the flight distance. Furthermore, when the hardness of the inner portion of the outer cover 1b is lower than the hardness of the surface side, the feel on impact is deteriorated and the durability is reduced.

Further, when the Shore D hardness of the inner portion of the jacket 1b is lower than the Shore D hardness of 0 to 4 mm from the surface of the core portion 1a toward the central portion, the flight distance becomes difficult. .

In the three-piece solid golf ball of the present invention, the diameter of the solid core 1 is usually 37 to 41 mm, and the diameter of the core portion 1a of the solid core 1 is 24 to 30 mm.
However, these ranges can be changed slightly.

The core portion 1a of the solid core 1 is usually a natural rubber and / or a synthetic rubber (for example, polybutadiene rubber, isoprene rubber, styrene-butadiene rubber, etc.).
A, a metal salt of an α, β-unsaturated carboxylic acid (eg, zinc acrylate, zinc methacrylate, etc.), or α, β
-Unsaturated carboxylic acid (for example, acrylic acid, methacrylic acid, etc.) and a metal oxide (for example, zinc oxide, magnesium oxide, etc.) are mixed, and if necessary, a filler, an antioxidant, a pigment, etc. are mixed. , And organic peroxides (eg,
Dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane,
α, α'-bis (t-butylperoxyisopropyl)
It is formed by using a rubber composition containing benzene etc.).

The outer cover 1b of the solid core 1 is formed of a rubber composition similar to that of the core portion 1a, but the base rubber is made of cis.
1,4 structure 40% or more, Mooney viscosity [ML _{1 + 4} (10
0 ° C.)], containing a polybutadiene rubber of less than 70, based on 100 parts by weight of the base rubber, a higher fatty acid (for example, palmitic acid, stearic acid, lauric acid, myristic acid,
Behenic acid, oleic acid, linoleic acid, linolenic acid, etc.)
Is preferably added in an amount of 0.5 to 2 parts by weight. When the outer cover 1b is formed of such a rubber composition, high resilience can be obtained and the hardness distribution can be easily controlled.

The cover 2 is usually formed by using an ionomer resin or a material containing the same, but natural or synthetic balata rubber, polyurethane resin or the like can also be used. The cover 2 has the same thickness as the cover of a conventional three-piece solid golf ball (for example, 1.5 to 2.5).
mm). When the cover 2 is soft, the feeling of hitting is soft, but when the solid core 1 is soft, the flight distance is short. On the contrary, when the cover 2 is hard, the flight distance is long, but when the solid core 1 is hard, the feel at impact becomes poor. In order to achieve a good balance between the feel on impact and the flight distance, it is preferable that the cover 2 be hard when the solid core 1 is soft and the cover 2 be soft when the solid core 1 is hard. For example, the solid core 1 and the jacket 1
The soft solid core 1 classified by the Shore D hardness in the range of 0 to 2 mm from the surface of b toward the inner side, and having a Shore D hardness in the range of 0 to 2 mm from the surface is less than 50.
In the case of, the Shore D hardness of the cover 2 is 63 or more,
In the case of a solid core 1 having a hardness of 50 or more, it is preferable that the Shore D hardness of the cover 2 is 67 or less.

[0015]

In the present invention, the jacket 1b of the solid core 1
Is harder than the core portion 1a of the solid core 1 and has a hardness in the range of 0 to 2 mm from the surface of the outer cover 1b softer than the inner portion thereof. The shock of time is alleviated.

[0016]

Since the three-piece solid golf ball of the present invention has a high resilience, a sufficient flight distance can be obtained. Further, since the impact at the time of hitting the ball is alleviated, the ball has a soft hit feeling and sufficient durability.

[0017]

EXAMPLES A solid core 1 having a two-layer structure was molded by using the rubber composition for the core portion 1a and the jacket 1b, which has the composition of Examples 1 to 5 and Comparative Examples 1 and 2 [Table 1]. Next, the solid core 1 was coated with the material of the cover 2 having the composition shown in [Table 1] to produce three-piece solid golf balls of Examples 1 to 5 and Comparative Examples 1 and 2. Table 2 shows the results of measuring the initial velocity efficiency, carry, durability, and feel at impact of the obtained three-piece solid golf ball.

[0018]

[Table 1]

* 1: BR-1 manufactured by Nippon Synthetic Rubber Co., Ltd.
8 (trade name), cis 1,4 structure 96%, Mooney viscosity [ML _{1 + 4} (100 ° C)] 59 * 2: Trade name, sodium ion neutralized ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd. * 3: Trade name, zinc ion neutralization type ionomer resin manufactured by Mitsui DuPont Polychemical Co., Ltd. * 4: Saponified ethylene-ethyl acrylate copolymer

[0020]

[Table 2]

Initial velocity efficiency : The ratio of the initial velocity of a golf ball to the club head velocity when hit by a No. 1 wood club (# 1) using a swing robot device.

Carry : Measured by using a swing robot apparatus with a No. 1 wood club (# 1) at a club head speed of 45 m / sec.

Durability : Evaluation was made by repeatedly hitting with a No. 1 wood club (# 1) at a club head speed of 45 m / sec using a swing robot apparatus. ○ Good, △ Normal, × Bad

Shot Feeling : Evaluated by actual hitting by a senior golfer for men. ◎ Extremely good, ○ Good, × Bad.

The golf balls of Examples 1 to 5 in Table 2 had higher initial velocity efficiency as compared with Comparative Examples 1 and 2, and the carry was good at 203.6 to 205.4 m. In addition, the hit feeling was soft and was evaluated to be extremely good. Also,
Durability was also rated above average.

On the other hand, the golf ball of Comparative Example 1 was evaluated as having a hard solid core and a bad feel on impact. In addition, the golf ball of Comparative Example 2 has a poor initial velocity efficiency despite the hard cover and has a carry of 202.
I didn't fly at 7m.

[Brief description of drawings]

FIG. 1 is an explanatory view of a cross-sectional structure of a three-piece solid golf ball.

[Explanation of symbols]

 1 ... Solid core 1a ... Core part 1b ... Envelope 2 ... Cover

Claims (3)

[Claims] 1. A three-piece solid golf ball in which a solid core composed of a core portion and an outer cover thereof is covered with a cover, wherein the core portion of the solid core is: (1) Shore D hardness of the center portion of the core portion: 15 ~ 45,
(2) 0 to 4 m from the surface of the core toward the center
Shore D hardness in the range of m: 45 or less, and (1)
≦ (2), the outer cover of the solid core is (3) Shore D hardness of the inner portion of the outer cover is 65 or less,
(4) 0 to 2 m from the surface of the jacket toward the inner part
Shore D hardness in the range of m: 40 or more, and (2)
<(3), (3)> (4), A three-piece solid golf ball. 2. The three-piece solid golf ball according to claim 1, wherein the Shore D hardness in the range of 0 to 2 mm from the surface of the outer cover of the solid core to the inner portion is less than 50. Is covered with the cover having a Shore D hardness of 63 or more, and when it is 50 or more, the solid core is covered with the cover having a Shore D hardness of 67 or less. 3. The three-piece solid golf ball according to claim 1, wherein the solid core has a cis-1,4 structure of 40% or more and a Mooney viscosity [ML _{1 + 4} (100 ° C.)] of less than 70. A three-piece solid golf ball, which is formed from a rubber composition containing 0.5 to 2 parts by weight of a higher fatty acid based on 100 parts by weight of a base rubber containing rubber.