JP2002219196A - Three-piece solid golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance golf ball which can demonstrate favorable spin performance according to the kind of a club with soft striking feeling without reducing its flying distance and durability, and which has a good flying distance, durability, striking feeling and spin controllability. SOLUTION: This three-piece solid golf ball has a three-layer structure comprising of a solid core, a middle layer and a cover, and it has a characteristic as follows: The deformation amount of a solid core when loaded is 2.5 mm or more; the Shore D hardness of the middle layer is higher than the Shore D hardness of the cover by 13 degrees or more; and the Shore D hardness of the cover is 35 to 55. The gravity of the middle layer is smaller than the gravity of the solid core and the gravity of the cover, and the gravity of the cover is 1.05 or more. Also, the moment of inertia for the whole ball comprised of three layers is 83 gcm2 or more. As a result of this, an excellent controllability can be attained, and the spin characteristic of approach shot by using a short iron or the like can be improved without reducing the flying distance of a full shot by a driver or a long iron. This ball rolls well on the green, moves straight favorably and it is also possible to attain an excellent durability because the ball is less prone to have scratches easily by being struck.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a three-layer structure of a solid core, an intermediate layer, and a cover, and has excellent spin performance, feel, controllability and a good flight distance. The present invention relates to a solid golf ball.

[0002]

2. Description of the Related Art Conventionally, golf balls include a solid golf ball in which a solid core is covered with synthetic rubber as a cover, and a thread wound core in which a thread rubber is wound around a liquid center and a balata rubber are used. A wound golf ball coated with natural rubber or synthetic rubber as a cover is commercially available, but there are many solid golf balls covered with synthetic rubber that can increase the flight distance and have excellent durability. In the meantime, there are still many professional golfers who use a thread-wound golf ball using a balata rubber as a cover (hereinafter referred to as a thread-wound balata ball).

It can be said that the reason is that the thread-wound balata ball has better hit feeling and spin controllability than golf balls of other structures. In other words, although professional golfers want golf balls with excellent flight distance,
There are few cases where this is the first condition for selecting a ball, and it is considered that the emphasis is placed on the hit feeling and spin controllability over the flight distance.

In order to meet the needs of such professional golfers and obtain golf balls that can be suitably used by ordinary golfers, various types of solid golf balls having excellent flight distance, hit feeling, and spin controllability have been developed. Proposals have been made.

[0005] For example, Japanese Patent Application Laid-Open No.
JP-A-4110 and JP-A-6-31980 propose a two-piece type solid golf ball having excellent hitting feel, good spin characteristics and improved controllability.

Also, various three-piece solid golf balls having a three-layer structure including a solid core, an intermediate layer covering the solid core, and a cover have been proposed (for example, Japanese Patent Application Laid-Open No. Sho.
8-92372, JP-A-5-193095, JP-A-6-343718, JP-A-7-194735, JP-A-7-194736, JP-A-8-82121, etc.), hit feeling and controllability. There have been various proposals for three-piece solid golf balls aimed at improving the quality.

However, many players still use thread-wound balata balls, and solid golf balls have not yet been able to satisfy these players in terms of feel and spin control. In particular, spin control is one of the most important performance in golf ball performance, and solid golf ball can improve spin control without deteriorating flight distance and hit feeling characteristics. desired.

Here, the spin characteristics of the solid golf ball can be improved to some extent by softening the cover, but when the cover is softened in this way,
As a result, the resilience of the ball is degraded and the flight distance is reduced, so that it is not possible to obtain the excellent flight performance characteristic of a solid golf ball.

A golf club for obtaining a flight distance of a driver or a long iron has a small loft angle.
On the other hand, a golf club for aiming at a pin (target) such as a short iron has a large loft angle and is designed so that the ball can be stopped at a target position rather than a flight distance. That is, when a golf ball is hit with a golf club, a force is applied to the golf ball in a direction perpendicular to the club face and a force parallel to the club face according to the loft angle of the club face. It contributes to resilience of the ball, and the force in the parallel direction contributes to spin the ball. In this case, when hitting with a driver with a small loft angle or a long iron,
While the force in the orthogonal direction acts greatly, the force in the parallel direction is relatively small, and it is designed so as to obtain a flight distance by a moderate repulsion force with a relatively low trajectory by appropriately controlling the spin amount. When hitting a short iron or the like with a large loft angle, the force in the parallel direction acts greatly, and the force in the orthogonal direction is relatively small, so that the ball is designed to give a larger spin amount than the flight distance.

Therefore, instead of simply increasing the spin amount, if the ball is hit with a driver or a long iron, the spin amount is appropriately suppressed, and the ball swells due to the spin (for a trajectory higher than necessary). If the ball hits with a club aiming at a target such as a short iron, a sufficient spin amount can be obtained, without reducing the flight distance or being affected by the wind.
It is required that the ball has a relatively high trajectory, has few runs (rolling) after the ball falls, and has excellent controllability. It is also important that the spin amount given at the time of hitting is maintained well during flight, in order to increase the flight distance and sufficiently exhibit spin controllability.

Further, in putting, unlike a normal shot in which a ball flies, the ball rolls on the green, so that the trajectory of the ball tends to change due to undulation on the green. In this case, putting is usually aimed directly at the hole, so the quality of the putting directly affects the score making, and therefore has a good rolling property and a high straightness without being affected by subtle undulations during putting. Golf balls that can provide the desired properties are desired.

The present invention has been made in view of the above circumstances, and it is possible to obtain excellent spin performance according to the type of a club to be hit, and it has a soft hit feeling, excellent controllability and excellent hit feeling. It is an object of the present invention to provide a golf ball capable of obtaining excellent rolling properties and obtaining these characteristics without deteriorating the excellent flight distance and durability, which are characteristics of a solid golf ball.

[0013]

Means for Solving the Problems and Embodiments of the Invention The present inventors have conducted intensive studies in order to achieve the above object, and as a result, a three-piece solid golf ball having a three-layer structure of a solid core, an intermediate layer and a cover. In the above, the solid core was prepared so that the deformation amount under a load of 100 kg was 2.5 mm or more, and the Shore D of the intermediate layer was adjusted.
The hardness is 13 degrees or more higher than the Shore D hardness of the cover, and in this case, the Shore D hardness of the cover is 35 to 55,
The specific gravity of the intermediate layer is smaller than the specific gravity of the solid core and the cover, the specific gravity of the cover is 1.05 or more, and the moment of inertia of the entire ball composed of these three layers is 83 gcm.
By setting it to ² or more, it is possible to demonstrate good spin performance according to the type of club with a soft hit feeling without lowering the flight distance and durability, flying distance, durability, hit feeling and spin controllability It has been found that a high-performance golf ball having an excellent golf ball performance can be obtained, and that the golf ball also has excellent rolling properties and good straightness on a green without being influenced by subtle undulations.

That is, the golf ball has improved spin control by the soft cover. In this case, in the golf ball, the resilience of the soft cover is reduced by the hard intermediate layer. Good resilience can be obtained more than enough. Further, the golf ball of the present invention is formed by softening the solid core so that the deformation amount under a load of 100 kg is 2.5 mm or more. The amount of spin when hitting with a club with a small loft angle such as a long iron can be moderately suppressed, a trajectory that does not rise and is flat and less affected by wind is obtained, and in combination with the above good resilience A good flight distance can be obtained. Further, this golf ball has a moment of inertia of 8
By making it relatively large, 3gcm ² or more, it excels in spin holding power during flight, and gives the final elongation to the trajectory without dropping too much in the amount of spin until falling when shot with a driver or long iron. In addition to being able to achieve a high level of control, a shot with a short iron reduces the number of runs after falling and provides sufficient spin control, as well as excellent rolling properties, and a subtle ange on the green when putting. It is possible to obtain a high straightness without being influenced by the ratio.

Accordingly, the present invention provides a three-piece solid golf ball having a three-layer structure of a solid core, an intermediate layer and a cover, wherein the solid core has a deformation amount of 2.5 mm or more under a load of 100 kg, The Shore D hardness of the layer is 13 more than the Shore D hardness of the cover.
Degree or higher, the cover has a Shore D hardness of 35 to 55, the specific gravity of the intermediate layer is smaller than the specific gravity of any of the solid core and the cover, and the specific gravity of the cover is 1.05 or more, and is composed of these three layers. Provided is a three-piece solid golf ball, wherein the moment of inertia of the entire ball is 83 gcm ² or more.

Hereinafter, the present invention will be described in more detail.
The golf ball of the present invention is a three-piece solid golf ball having an intermediate layer 2 between a solid core 1 and a cover 3, as shown in FIG.

Here, each layer will be described in detail. First, the solid core 1 constituting the central core of the golf ball is:
As described above, the amount of deformation under a load of 100 kg is 2.
It is prepared to be 5 mm or more, preferably to 2.8 mm or more. In this case, the deformation amount of the core 1 under a load of 100 kg is 2.
If it is less than 5 mm, the ball may be swung due to excessive spin when shot with a driver or a long iron, and the hit feeling when shot with these clubs may be hardened.

Although the diameter of the solid core 1 is not particularly limited, it is usually formed to be 33 to 38 mm, especially 34 to 37 mm. 33mm in diameter
If it is smaller, the resilience will be reduced. If it is larger than 38 mm, the intermediate layer 2 or the cover 3 will need to be thinned, which may cause inconvenience such as deterioration of durability.

This solid core can be manufactured by a known method, and can be formed by heating, pressing and molding a known rubber composition in which a co-crosslinking agent and a peroxide are mixed with a base rubber. .

In this case, as the base rubber, polybutadiene rubber or a mixture of polybutadiene rubber and polyisoprene rubber which has been conventionally used for the core of a solid golf ball can be used. 1,4 having a cis structure of 90% or more to obtain
The use of polybutadiene rubber is preferred.

As a co-crosslinking agent, a solid golf ball has conventionally used an ester compound such as a zinc salt or a magnesium salt of an unsaturated fatty acid such as methacrylic acid or acrylic acid, or trimethylpropane trimethacrylate. These can also be used, but zinc acrylate can be suitably used particularly because of its high resilience. The amount of these co-crosslinking agents is preferably 15 to 35 parts by weight based on 100 parts by weight of the base rubber.

Various peroxides can be selected. Particularly, dicumyl peroxide or dicumyl peroxide and 1,1-bis (t-butylperoxy) 3,3,5
Mixtures with trimethylcyclohexane are preferred.
The compounding amount is 0.5 to 100 parts by weight of the base rubber.
Preferably it is 1 part by weight.

The rubber composition may further contain, if necessary, zinc oxide, barium sulfate and the like as an antioxidant and a filler for adjusting specific gravity.

Next, the intermediate layer 2 has a Shore D hardness higher than that of the cover 3 by 13 degrees or more. Although not specifically limited, Shore D hardness is 60.
The cover 3 preferably has a hardness of 13 to 40 degrees, especially 13 to 30 degrees higher than the Shore D hardness of the cover 3. The intermediate layer 2 is made of a relatively hard layer to compensate for a decrease in resilience due to a soft cover 3 described later. If the Shore D hardness is too low, the resilience of the ball decreases and the flight distance decreases. Will be invited.

Although the thickness of the intermediate layer 2 is not particularly limited, it is usually 1.4 to 4 mm, particularly 1.3 to 4 mm.
Preferably, it is formed to 2.6 mm.

The intermediate layer 2 is for compensating for a decrease in the resilience of the cover 3, which is formed as described above, and is made of a material which is relatively hard and has excellent resilience, and is not particularly limited. However, specifically, Himilan 170
6,1605 (manufactured by DuPont-Mitsui Polychemicals) and ionomer resins such as Surlyn (manufactured by DuPont). Among them, preferably used are Himilan 1706 and Himilan 1605 alone or as a 1: 1 blend. Can be. In this intermediate layer, specific gravity can be adjusted by adding an inorganic filler such as zinc oxide or barium sulfate as a weight adjuster in addition to the ionomer resin, and adding titanium dioxide (pigment) or the like. An agent may be added.

Further, the cover 3 has a Shore D hardness lower than that of the intermediate layer 2 by 13 degrees or more. Specifically, although not particularly limited, Shore D hardness is 3
5 to 55, especially 37 to 53, 13
It is preferable that the angle is lower by 40 to 40 degrees, particularly 13 to 30 degrees. The cover 3 is made of a soft layer to improve the spin characteristics. If the Shore D hardness is too high, the spin characteristics are deteriorated and good spin controllability cannot be obtained, thereby achieving the object of the present invention. Can not be done. On the other hand, if the hardness difference between the cover 3 and the intermediate layer 2 is less than 13 degrees, it becomes impossible to achieve both spin characteristics and resilience.

Although the thickness of the cover 3 is not particularly limited, it is usually 1 to 3 mm, especially 1.3 to 2.2.
It can be formed to 5 mm.

The cover 3 can be formed using a known material. For example, an ionomer resin, a thermoplastic polyurethane elastomer, a polyester elastomer, a polyamide elastomer, or the like is used alone as a main material.
Alternatively, a resin mixture in which a urethane resin, an ethylene-vinyl acetate copolymer, or the like is mixed with these resins can be used. In the present invention, a thermoplastic polyurethane elastomer is used because it is soft and has excellent scratch resistance. It is particularly preferable to use this thermoplastic polyurethane elastomer alone. Examples of the thermoplastic polyurethane elastomer include Pandex (manufactured by Dainippon Ink and Chemicals, Inc.).

Here, the specific gravity of the solid core 1, the intermediate layer 2, and the cover 3 constituting the golf ball of the present invention is not particularly limited, and can be appropriately set. It is preferable that the specific gravity of the intermediate layer 2 is smaller than the specific gravity of any of the solid core 1 and the cover 3.
Although not particularly limited, the specific gravity of the solid core 1 is 1.1 to 1.3, particularly 1.11 to 1.27,
Has a specific gravity of 0.93 to 1, particularly 0.95 to 0.99, and a specific gravity of the cover 3 is 1.05 to 1.3, particularly 1.1 to 1.25.
It is preferred that

The golf ball of the present invention is a solid golf ball having a three-layered structure including the solid core 1, the intermediate layer 2, and the cover 3, and having a three-layered ball having an overall moment of inertia of 83 gcm ² or more. It was prepared as follows.

Here, the moment of inertia will be described in detail. The appropriate range of the moment of inertia changes depending on the correlation with the cover hardness. That is, if the cover is hard, the cover needs to be large, and if the cover is soft, the cover does not need to be large.
The reason is that if the cover is soft, it tends to spin because of the high frictional force at impact, and if the cover is hard, it is difficult to spin because the frictional force is small, so a hard cover and a low spin rate were used. If the moment of inertia is small, the spin will attenuate quickly and stall when falling.On the other hand, if the ball is launched with a soft cover and a high spin rate, the spin decay will be too large if the moment of inertia is too large. Because of the small size, spinning more than necessary during the flight will make you feel more like
In any case, the flight distance tends to decrease.

Therefore, according to the golf ball of the present invention, which has a soft structure in which a soft cover and a soft core are combined as described above, so that the spin amount when shot with a driver or a long iron is appropriately suppressed. By increasing the spin holding power during flight and maintaining a good spin amount until the end of the flight, a trajectory with elongation to the end is obtained, and a high moment of inertia is necessary to increase the flight distance. Yes, the moment of inertia of the ball is 83 gcm ² or more, preferably 83.5 to 85.5.
gcm ² , more preferably 84 to 85.3 gcm ² . Therefore, when the moment of inertia is less than 83 gcm ² , the spin holding force is not sufficient, and an extended trajectory cannot be obtained, resulting in a reduction in flight distance.

Further, by increasing the moment of inertia in this way, the rolling property on the green at the time of putting is improved, and a high straightness can be obtained without being influenced by a subtle undulation on the green. It is.

The moment of inertia can be measured by a known method. Specifically, a moment of inertia measuring device (INERTIA DYNAMICS IN) is used.
(Manufactured by C Company), and the natural frequency X can be calculated by introducing the measured value X into the following equation (1).

[0036]

(Equation 1) M: Moment of inertia A: Constant 1.12 B: Natural frequency of ball C: Natural frequency only with mounting jig D: Natural frequency with calibration weight E: Natural frequency with no load

As described above, the golf ball of the present invention
By optimizing the hardness of each layer of the solid core 1, the intermediate layer 2, and the cover 3, and optimizing the moment of inertia of the entire ball composed of these three layers, it is good when hit with a driver or a long iron. With excellent resilience, trajectory without run-up due to moderately suppressed spin amount, and trajectory with elongation due to good spin holding power,
Increases the flight distance, and when hit with a short iron or pitching wedge, it can obtain a ball with excellent controllability that stops well due to spin characteristics, can aim at the pin deadly, and puts on the green In the case of performing, due to the excellent rolling properties, good straightness that is hardly influenced by undulation is obtained, and a soft good hit feeling is obtained in any shot and putting, in every scene during the round, It can exhibit excellent performance.

A large number of dimples can be formed on the surface of the golf ball of the present invention in the same manner as a normal golf ball. In this case, the arrangement of the dimples is not particularly limited, and a known arrangement such as a regular octahedral arrangement, a regular dodecahedral arrangement, and a regular icosahedral arrangement can be employed. The pattern drawn on the square, hexagon, pentagon,
Various patterns such as a triangle shape can be used.
The number of dimples is 360 to 450, particularly 372
Preferably, the dimple has a diameter of
Although two or more kinds of different depths and the like can be used, the diameter is usually 2.2 to 4.3 mm,
The depth is preferably in the range of 0.1 to 0.24 mm.

Further, in the golf ball of the present invention, the ball properties such as ball weight and diameter can be appropriately set according to the Rules of Golf, and the manufacturing method is not limited, and the solid core 1, the mid layer 2 and the cover are not limited. A known method of forming each layer of No. 3 by compression molding, injection molding or the like can be adopted.

[0040]

According to the three-piece solid golf ball of the present invention, the relationship between the hardness of each layer consisting of the solid core, the intermediate layer and the cover is optimized, and the moment of inertia of the entire ball comprising these three layers is optimized. By
Without reducing the flight distance when taking a full shot with a driver or long iron, the spin characteristics on approach shots using a short iron etc. can be improved and excellent controllability can be obtained, and on the green It is possible to obtain an excellent rolling property, a good straight running property, and an excellent durability in which abrasion due to impact is difficult to occur.

[0041]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Examples and Comparative Examples A rubber composition having the composition shown in Table 1 (all parts by weight) was kneaded and vulcanized.
A solid core having the properties shown in Table 3 was obtained, and an intermediate layer and a cover having the properties shown in Table 3 were formed on the solid core by injection molding using any of the compositions shown in Table 2 to obtain a three-piece solid. Golf ball (Examples 1 to
5, Comparative Examples 1 and 2) were obtained. The thread-wound golf ball of Comparative Example 3 was a commercially available product (T
HE REXTAR) was used.

For each of the obtained golf balls, the moment of inertia, flying performance, spin performance, hit feeling, durability and rolling property on a green were evaluated by the following methods. Table 3 shows the results.

Moment of inertia measuring device (INERTIA DYNAMI)
CS Inc.), and calculated by introducing the measured value X into the following equation (1).

[0045]

(Equation 2) M: Moment of inertia A: Constant 1.12 B: Natural frequency of the ball C: Natural frequency only with the mounting jig only D: Natural frequency with the calibration weight E: Natural frequency with no load

Flying performance Using a swing robot manufactured by True Temper, measurement of spin, carry, and total flying distance when shot with a driver (# W1) at a head speed of 50 m / sec (HS50). did.

Spin performance Using a swing robot similar to the above, a head speed of 25 m / sec (H) was obtained using a sand wedge (#SW).
The spin amount and the run distance when the shot was taken in S25) were measured.

A professional golfer with three feelings shots at a head speed of about 45 m / sec (HS45) using a driver, and a head speed of about 5 m / sec using a putter.
The shot feeling when shot with c (HS5) was evaluated according to the following criteria. ○: very soft △: normal ×: hard

Scratch The pitching wedge (#
Head speed 33m / sec (HS3
In 3), the degree of damage of the hitting point during the shot was visually evaluated based on the following criteria. ：: No scratches or scratches, but no concern at all ×: Marked scratches

Rolling property on green A three-player professional golfer evaluated the rolling condition of the ball when actually hit on the green using a putter (#PT) according to the following criteria. ：: straightness and rolling elongation ×: lack of linearity and no elongation

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 3]

As shown in Table 3, the golf ball of the present invention has a flight distance, spin control property, feeling,
It was confirmed that both the abrasion resistance and the rolling property were excellent. On the other hand, the golf ball of Comparative Example 1 has a high core hardness and a small moment of inertia, so that the spin performance is insufficient, and the golf ball has a large number of runs when hit by #SW and a rolling property on the green during putting. (Straightness), and also have poor abrasion resistance and poor durability. In addition, the golf ball of Comparative Example 2 has too high a cover hardness, a small difference in hardness between the intermediate layer and the cover, and an insufficient moment of inertia, resulting in poor spin characteristics and does not require a large amount of spin. #A large amount of spin is obtained at the time of hitting W1, but a small amount of spin is required at the time of hitting #SW which requires a large amount of spin.
Runs when hitting W are increasing. In addition, it has poor rolling properties (straightness) on the green during putting. Furthermore, the thread-wound golf ball of Comparative Example 3 was # W1
The spin amount is too large, and the moment of inertia is too small, so the trajectory tends to rise and the final elongation is lacking, so the flight distance is poor, and the rolling property on the green at the time of putting is also poor, Further, they are easily scratched and have poor durability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a three-piece solid golf ball of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solid core 2 Middle layer 3 Cover

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Dr. Higuchi 20, Onohara, Chichibu, Saitama Prefecture, Bridgestone Sports Co., Ltd. (72) Inventor Junji Hayashi, 20 Onohara, Chichibu City, Saitama Prefecture, Japan Nobuhiko Matsumura 4-17-305, Jonancho, Izumiotsu-shi, Osaka

Claims (4)

[Claims] 1. A three-piece solid golf ball having a three-layer structure of a solid core, an intermediate layer, and a cover, wherein the solid core has a deformation amount of 2.5 mm or more under a load of 100 kg, and a shore D of the intermediate layer. The hardness is at least 13 degrees higher than the Shore D hardness of the cover, the Shore D hardness of the cover is 35 to 55, the specific gravity of the intermediate layer is smaller than that of either the solid core or the cover, and the specific gravity of the cover is 1. 05 or more and these three
The moment of inertia of the entire ball composed of layers is 83 gcm ²
A three-piece solid golf ball characterized by the above. 2. The three-piece solid golf ball according to claim 1, wherein the mid layer has a Shore D hardness of 60 to 70. 3. The three-piece solid golf ball according to claim 1, wherein the cover is formed mainly of a thermoplastic polyurethane elastomer. 4. A moment of inertia of 84 to 85.3 gcm.
The three-piece solid golf ball according to any one of claims 1 to 3, which is ² .