JPH10328326A - Multi-piece sold golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a favorable shooting feeling at the time of a full shot by a driver, regardless of a degree of the head speed while keeping a high repulsion, and at the same time, provide an excellent spinning performance at the time of an approach shot by a sandwedge, etc., and an excellent shooting feeling at the times of an approach shot and a putting. SOLUTION: For this multi-piece solid golf ball wherein a core 2 comprises an inner core ball 3 and a surrounding layer 4 which covers the inner core ball 3, and a cover 5 which covers the core 2 comprises an external layer and an internal layer, the external layer hardness of the cover 5 is 40-60 by a Shore D, and the internal layer hardness of the cover 5 is 55-70 by the Shore D, and the surface hardness of the surrounding layer is higher than the surface hardness of the inner core ball by the Shore D, and the hardness of the inner core ball 3 is 3.0-8.0 mm by a deformation amount when a load of 100 kg is loaded, and a ratio of the inner code ball hardness A and the ball hardness B is 1.1<=A/B<=3.5 by a deformation amount when a load of 100 kg is loaded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer solid golf ball having a four-layer structure in which a core comprises an inner sphere and an envelope layer for covering the inner sphere, and a cover for covering the core comprises an outer layer and an inner layer. More specifically, it has excellent spin performance on approach shots with sand wedges, etc., has a soft hit feeling when approaching and putting, and fly regardless of the head speed during full shots with the driver. The present invention relates to a multi-piece solid golf ball that has an increased distance and is soft and has a good hit feeling.

[0002]

2. Description of the Related Art
A two-piece solid golf ball in which a rubber-based core is covered with a cover made of an ionomer resin or the like has excellent flight performance and durability, but has a disadvantage in that the hit feeling is hard. For this reason, various soft two-piece solid golf balls have been proposed. In order to obtain such a soft type two-piece solid golf ball, a soft core is generally used,
When the core is softened, the resilience is reduced, the flying performance is deteriorated, and the durability is also significantly reduced. Not only the excellent flying performance and durability characteristic of the two-piece solid golf ball are not obtained, but also the actual It may be difficult to use.

[0003] For this reason, many three-piece solid golf balls have been proposed. For example, in a solid three-piece golf ball in which a core composed of an inner layer and an outer layer is covered with an outer skin, a soft, relatively small inner layer (outer diameter:
24-29 mm, hardness: Shore D15-30) hard outer layer (outer diameter: 36-41 mm, hardness: Shore D55-6)
5) having a core covered with 5) and having a great flight distance, a feeling of impact extremely close to a thread-wound golf ball, and controllability (Japanese Patent Publication No. 4-55077, JP-A-64-8)
No. 0377), in a three-piece solid golf ball comprising a center core, an intermediate layer, and a cover, a soft intermediate layer is provided around the softly formed center core, and the thickness, specific gravity of the center core, the intermediate layer, and the cover are provided. Is set in a specific range to improve the feeling without deteriorating the flight performance and durability (Japanese Patent Laid-Open No. 7-24084), and includes a center core, an intermediate layer, and a cover. In a three-piece solid golf ball, a relatively hard intermediate layer is formed between a relatively soft core and a cover to improve the feeling and controllability without deteriorating flying performance and durability ( JP-A-7-2408
No. 5) has been attempted.

[0004] However, although there is no regulation regarding the cover, when a soft member is used for the cover, the resilience is not sufficient and the flight distance is short. On the other hand, when a hard member is used for the cover, since the cover and the core outer layer inside the cover are hard, the hit feeling during an approach shot, which is a small deformation region, is particularly hard. The soft core and the intermediate layer improve the hit feeling with a driver, but the cover is hard, so that the hit feeling with a sand wedge is hard, and the spin is not sufficiently applied and controllability is poor. In the case of the core, the core most affecting the feel and resilience is formed relatively soft, and in the range where the feel is sufficiently soft, the resilience becomes insufficient and the flight distance is short. On the other hand, if the resilience is in a sufficient range, the core is slightly hard and the hit feeling is not sufficiently soft, and the middle layer is also hard, so that a player with a low head speed cannot give sufficient deformation to the ball, and Each of them has a problem that a sufficient distance cannot be obtained, and there is still room for improvement.

The present invention has been made in view of the above circumstances, and a multi-piece solid golf having a core comprising an inner sphere and an envelope layer covering the inner sphere, and a cover covering the core comprising an outer layer and an inner layer. The ball has excellent spin performance when approaching shots with a sand wedge, etc., has a soft feel when approaching and putting, and increases the flight distance regardless of the head speed when driving with a full shot. It is an object of the present invention to provide a soft multi-piece solid golf ball having a good hit feeling.

[0006]

Means for Solving the Problems and Embodiments of the Invention The present inventor has conducted intensive studies to achieve the above object, and as a result, the core was formed from the inner core sphere and the surrounding layer covering the inner sphere. In a multi-piece solid golf ball in which a cover covering the core is composed of an outer layer and an inner layer, a core composed of a soft inner core ball and a relatively hard surrounding layer is covered with a cover composed of a soft outer layer and a hard inner layer. By forming a layered structure, the soft outer layer of the cover improves the spin performance at the time of approach shot with sand wedge etc., and the hit feeling at the time of approach shot and putting becomes soft, and the inner layer of the cover By using hard and good resilience resin, good flight performance can be maintained, and the inner core ball is formed softly, By covering the surrounding layer made of a relatively hard and highly resilient member, a very soft feel can be obtained while maintaining high resilience regardless of the head speed during a full shot with a driver. , Respectively.

As a result of further intensive studies based on the above findings, the core is composed of an inner core sphere and an envelope layer covering the inner core sphere, and the cover covering the core is composed of an outer layer and an inner layer. In the solid golf ball, the outer layer hardness of the cover is 40-60 in Shore D, the inner layer hardness of the cover is 55-70 in Shore D, and the surface hardness of the surrounding layer is higher than the surface hardness of the inner sphere in Shore D. Then, the hardness of the inner core sphere is set to 3.0 to 8.0 mm in the amount of deformation under a load of 100 kg, and the ratio of the inner core sphere hardness A to the ball hardness B is 1. By forming 1 ≦ A / B ≦ 3.5, the ball is sufficiently deformed when a full shot with a driver, which is a large deformation area of the ball, especially when a player with a low head speed hits. Irrespective of the level of head speed, while maintaining high resilience, the flight distance is dramatically increased by an appropriate amount of spin, giving a soft and very good feel and Spin is applied well at the time of approach shot or putting with sand wedge etc. which is the deformation area, has excellent controllability and soft and good hit feeling, and can effectively solve the problem in the conventional three-piece solid golf ball The inventors have found that a multi-piece solid golf ball can be obtained, and have completed the present invention.

Accordingly, the present invention provides (1) a multi-piece solid golf ball according to the above (1), wherein the core comprises an inner sphere and an envelope layer covering the inner sphere, and a cover covering the core comprises an outer layer and an inner layer. The outer layer hardness of the cover is Shore D
And the inner layer hardness of the cover is Shore D.
55 to 70, the surface hardness of the surrounding layer is higher than the surface hardness of the inner sphere at Shore D, and the hardness of the inner sphere is 100 kg.
The deformation amount under load is 3.0 to 8.0 mm, and the ratio between the inner core ball hardness A and the ball hardness B is 1.1 ≦ A / B ≦ 3.5 at a load amount of 100 kg load. (2) The multi-piece solid golf ball according to (1), wherein the inner core ball is mainly composed of a rubber base material, has a diameter of 20 to 37 mm, and a core diameter of 32 to 41 mm. Peace solid golf ball, (3) the thickness of the outer layer of the cover is 0.3 to 3.0 mm, and the thickness of the inner layer of the cover is 0.3 mm.
The multi-piece solid golf ball according to (1) or (2), wherein the hardness difference between the outer layer and the inner layer is 5 or more in Shore D, and (4) the hardness of the inner layer of the cover is the outer layer hardness. A multi-piece solid golf ball according to (1), (2) or (3), which is formed higher.

Hereinafter, the present invention will be described in more detail. The multi-piece solid golf ball 1 of the present invention
As shown in FIG. 1, a core 4 composed of an inner core sphere 3, an envelope layer 4 covering the inner core sphere, and a cover 5 composed of an inner layer 6 and an outer layer 7 formed around the core. This is a golf ball having a layer structure. The surrounding layer 4 is not limited to a single layer, and may be formed in two or more layers.

The hardness of the inner core ball 3 constituting the core 2 of the golf ball 1 of the present invention is 3.0 to 8.0 mm in terms of deformation under a load of 100 kg, and more preferably 3.5 to 8.0 mm.
7.5 mm. When the deformation amount is less than 3.0 mm, the core becomes too hard, and particularly in a player with a low head speed, the flight distance decreases and the hit feeling becomes hard. On the other hand, 8.0m
If it exceeds m, the core will be too soft, and the resilience and durability will be too low. The surface hardness of the inner sphere is Shore D
It is preferably from 15 to 55, more preferably from 20 to 50, as measured by a hardness tester (hereinafter referred to as Shore D). Here, the surface hardness of the inner sphere indicates the hardness of the surface of the inner sphere,
It is the average value of five-point measurements.

The diameter of the inner sphere is preferably 20 to 3
7 mm, more preferably 22 to 35 mm. In addition,
The specific gravity, weight, and the like of the inner core sphere can be appropriately adjusted as long as the object of the present invention can be achieved.

In the present invention, the composition for forming the inner core sphere is not particularly limited, and a rubber base material usually used for forming the inner core sphere is mainly used.
It can be formed by adding a co-crosslinking agent, an inert filler or the like. In this case, as the rubber substrate, natural rubber and / or synthetic rubber conventionally used for solid golf balls can be used. In the present invention, 1,4 having at least 40% or more of the cis structure is used. -Cis-polybutadiene is particularly preferred. In this case, if necessary, natural rubber, polyisoprene rubber, styrene-butadiene rubber, or the like may be appropriately blended with the polybutadiene. Examples of the crosslinking agent include organic peroxides such as dicumyl peroxide and di-t-butyl peroxide. The amount of the crosslinking agent is usually about 0.5 to 2.0 parts by weight based on 100 parts by weight of the base rubber component.

The co-crosslinking agent is not particularly limited.
Metal salts of unsaturated fatty acids, especially unsaturated fatty acids having 3 to 8 carbon atoms (for example, acrylic acid, (meth) acrylic acid, etc.)
Examples thereof include zinc salts and magnesium salts, and zinc acrylate is particularly preferred. The compounding amount of the co-crosslinking agent is appropriately set, and usually is 5 to 100 parts by weight of the base rubber component.
About 50 parts by weight. Further, examples of the inert filler include zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate, and the like. Zinc oxide and barium sulfate are generally used, and the amount of the filler is determined by the specific gravity of the core and the cover, and the amount of the ball. The weight is usually 5 to 100 parts by weight based on 100 parts by weight of the base rubber. In the present invention, the crosslinking agent and zinc oxide,
The hardness and weight of the inner sphere can be adjusted to optimal values by appropriately adjusting the mixing ratio of the filler such as barium sulfate.

The composition for the inner core sphere obtained by blending the above components is kneaded using a conventional kneading machine, for example, a Banbury mixer or a roll, and the inner core sphere having the above hardness is formed using a mold for the inner core sphere. Can be formed.

The surrounding layer 4 covering the inner core sphere 3 has a Shore D surface hardness of preferably 40 to 70, more preferably 45 to 68. The surface hardness of the envelope layer needs to be higher than the surface hardness of the inner core sphere, and specifically, Shore D is preferably 5 to 55, and more preferably 5 to 55.
45 higher. If the surface hardness of the surrounding layer is lower than the surface hardness of the inner core sphere, the resilience and durability are too low. Note that the definition and measurement method of the surface hardness of the surrounding layer are the same as those for the inner core sphere. When the surrounding layer is composed of two or more layers, the surface hardness of the surrounding layer is the surface hardness of the outermost surrounding layer. Refers to hardness.

The thickness of the surrounding layer is preferably 0.5 to
It is 10.5 mm, more preferably 1 to 9 mm, and the specific gravity can be appropriately adjusted within a range that can achieve the object of the present invention.

The surrounding layer 4 is preferably made of a member that is relatively hard and has good resilience, and may be formed of a rubber base material as in the case of the inner core ball, or a thermoplastic resin. It may be formed as a main material. In this case, as the thermoplastic resin, for example, polyester-based thermoplastic elastomer such as Hytrel 4767 (manufactured by Toray DuPont),
Ionomer resins such as Himilan (manufactured by DuPont-Mitsui Polychemicals) and Surlyn (manufactured by DuPont, USA) are suitably used, and one of these can be used alone or two or more can be used in combination. In addition, an inorganic filler such as zinc oxide or barium sulfate or an additive such as titanium dioxide for coloring can be added as a weight adjuster in addition to the resin composition.

The method of coating the inner sphere 3 with the surrounding layer 4 is not particularly limited. When the surrounding layer is a rubber member, it is preliminarily formed into a half cup shape in a semi-vulcanized state. A method in which the inner core sphere is covered with a half cup and heated and pressed under a predetermined condition is adopted. On the other hand, when the envelope layer is made of a thermoplastic resin, the molten envelope layer composition is injected with the inner core sphere by injection molding. And the like.

The core 2 thus obtained preferably has a diameter of 32 to 41 mm, more preferably 34 to 41 mm.
40 mm.

The cover 5 for covering the core 2 includes an inner layer 6
And an outer layer 7. The outer layer 7 covers the inner layer 6. The outer layer 7 of the cover has a Shore D hardness of 40-60, preferably 42-58. If the hardness of the outer layer is less than 40, the resilience is too low, and 6
If it exceeds 0, the spin performance at the time of the approach shot is reduced, and the hit feeling becomes hard. The hardness of the inner layer 6 of the cover is
When the Shore D is 55 to 70, and the hardness of the inner layer is less than 55, the resilience is too low, and when the hardness is more than 70, the hit feeling is too hard. Further, the inner layer hardness of the cover is preferably higher than the outer layer hardness, and the hardness difference between the inner layer and the outer layer is preferably 5 or more, more preferably 5 to 25, in Shore D.

The thickness of the cover outer layer is preferably 0.3
To 3.0 mm, more preferably 0.5 to 2.5 mm, and the thickness of the cover inner layer is preferably 0.5 to 3.0 m.
m, more preferably 0.7 to 2.8 mm. Also,
The total thickness of the cover including the outer layer and the inner layer is preferably 0.8 to 5.4 mm, and more preferably 1.3 to 4.4 m.
m.

The material constituting the cover inner layer includes:
A resin that is hard and has excellent resilience is preferable. For example, Himilan AM7317, AM7318, 1605, and 17
Commercially available ionomer resins such as No. 06, No. 1557 and No. 1856 (manufactured by DuPont-Mitsui Polychemicals) are preferable, and others include thermoplastic resins such as polyesters, polyamides and polyurethanes. Two or more kinds can be used as a mixture.

The material constituting the cover outer layer includes:
There is no particular limitation, and commercially available ionomer resins such as Surlyn 8120 (manufactured by Dupont, USA) and Himilan 1706 (manufactured by Dupont Mitsui Polychemicals), thermoplastic resins such as polyester, polyamide, and polyurethane are preferably used. The species can be used alone or as a mixture of two or more.

Further, the composition for the inner layer and the outer layer of the cover includes:
If necessary, a UV absorber, an antioxidant, and a dispersing aid such as a metal soap can be added.

The method of coating the cover around the core is not particularly limited. Usually, the core is wrapped in two half cups previously formed into a half-shell sphere, and the core is heated and pressed, or the cover composition is prepared. Injection molding may be performed around the core.

The hardness of the golf ball obtained in this manner is preferably the amount of deformation under a load of 100 kg, preferably 2.
It is 3 to 4.0 mm, more preferably 2.5 to 3.8 mm. In this case, the ratio between the hardness A of the inner core ball and the hardness B of the golf ball is 1.1 in the amount of deformation under a load of 100 kg.
≦ A / B ≦ 3.5, preferably 1.1 ≦ A / B ≦
3.0. If A / B is less than 1.1, the ball becomes too soft and the resilience decreases, and if it exceeds 3.5, the ball is too hard and the hit feeling becomes hard.

The properties of the ball, such as the weight and diameter of the ball, can be appropriately set in accordance with the Rules of Golf.

With the golf ball of the present invention having the above-described structure, the dependence of the head speed on the driver is extremely small, and the influence of the club number is extremely small. In other words, when a full shot with a driver, which is a large deformation area of the ball, especially when a player with a low head speed makes a full shot, the ball can be sufficiently deformed, and high resilience is obtained regardless of the head speed. While maintaining, a soft and very good hit feeling can be obtained, and a good spin can be applied at the time of approach shot or putting with a sand wedge etc., which is a small deformation area of the ball, excellent controllability and soft and good hit feeling It has.

[0029]

According to the present invention, a good hit feeling can be obtained while maintaining high resilience irrespective of the head speed during a full shot with a driver, and a spin at the time of an approach shot with a sand wedge or the like can be obtained. It is excellent in performance and hit feeling at the time of approach shot and putting.

[0030]

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] An inner core sphere composition having the composition shown in Table 1 was kneaded using a kneading roll and vulcanized in a mold at 155 ° C for 15 minutes to prepare an inner core sphere. did. When the surrounding layer is a rubber member on the inner core sphere, Table 1
The rubber composition of the formula shown in the following is kneaded with a kneading roll and molded in a half-cup shape in a semi-vulcanized state. Cores were obtained by pressing (Examples 5 and 6). On the other hand, when the envelope layer was a thermoplastic resin, the envelope layer composition was injection-molded around the inner core sphere according to the formulation in Table 1 to obtain a core (Example 1).
4).

The inner layer and the outer layer of the cover prepared according to the formulation shown in Table 1 were sequentially injection-molded on the obtained core to obtain golf balls having a four-layer structure of Examples 1 to 6. Comparative Examples 1 to 3 are three-piece solid golf balls having a core and a two-layer cover, and Comparative Example 4 are two-piece golf balls having a core and a one-layer cover. In addition, the compounding amount shown in Table 1 is all parts by weight, and the amount ratio is the inner sphere,
The envelope layer, the inner layer of the cover, and the outer layer are independent of each other.

[0033]

[Table 1] * 1: Ionomer resin manufactured by DuPont, USA * 2: Ionomer resin manufactured by DuPont Mitsui Polychemicals * 3: Polyester thermoplastic elastomer manufactured by Dupont Toray

Next, the flying performance and the hit feeling of the obtained golf ball were measured according to the following methods. Table 2 shows the results
Shown in

Flying performance Using a swing robot, a driver (PRO 2
Head speed 50m / at 30 Titan, 10 degree loft angle (Bridgestone Sports Co., Ltd .; # W1)
sec (HS50) and head speed 35m / sec
Spin amount when shot with, fall distance (carry),
The reaching distance (total) was measured. Also, the amount of spin when a shot was taken at a head speed of 20 m / sec (HS20) with a sand wedge (J's Classical Edition (Bridgestone Sports Co., Ltd .; #SW)) was measured.

The head speed is about 50 m by the feel driver (# W1).
/ Sec (HS50) with 5 professionals, head speed about 3
The feeling when five female top amateurs actually hit at 5 m / sec was evaluated according to the following criteria. ：: Soft △: Normal ×: Hard In addition, the feel when five professional golfers actually hit with a sand wedge (#SW) at a head speed of about 20 m / sec (HS20) was evaluated according to the following criteria. ○: Soft △: Normal ×: Hard

[0037]

[Table 2] * 4: Deformation amount under 100 kg load (mm)

From the results shown in Table 2, Comparative Example 1 shows that
US Patent No. 24084 is a three-piece golf ball of the same type as that described in Japanese Patent Publication No. It is hard and does not take enough spin. Comparative Example 2
Is a three-piece golf ball having the same type of soft core as that described in Japanese Patent Application Laid-Open No. 7-24085. The soft core has a soft hitting sensation with a driver, but the core and cover are both soft, so the resilience is poor. It is enough and the flight distance is not enough. Comparative Example 3 is disclosed in
A core of the same type as that described in Japanese Patent No. 24085 is a slightly harder three-piece golf ball, which has a slightly hard hitting feel, and particularly a poor hitting feel at a low head speed and poor flight distance. Comparative Example 4 is a general spin-type two-piece golf ball, which has excellent spin performance and hit feeling with a sand wedge, but has a hard core and a single-layer soft cover, so that the hit feeling with a driver is low. Become harder,
The flight distance is not sufficient due to an increase in the spin amount.

On the other hand, in the multi-piece solid golf ball of the present invention, the flight distance is increased irrespective of the head speed of the driver, so that a soft hit feeling is obtained, and the soft whit feeling is obtained with the sand wedge. It was confirmed that spin performance was obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a golf ball according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Golf ball 2 Core 3 Inner core ball 4 Surrounding layer 5 Cover 6 Inner layer 7 Outer layer

Claims (4)

[Claims] 1. A multi-piece solid golf ball in which a core comprises an inner core ball and an envelope layer covering the inner core ball, and a cover covering the core comprises an outer layer and an inner layer. The hardness of the inner layer of the cover is 55 to 70 at Shore D, and the surface hardness of the surrounding layer is higher than the surface hardness of the inner core ball at Shore D.
The hardness of the inner core ball is 3.0 to 8.0 mm in the amount of deformation under a load of 100 kg, and the ratio between the inner core ball hardness A and the ball hardness B is 1.1 in the amount of deformation under a load of 100 kg.
≦ A / B ≦ 3.5. A multi-piece solid golf ball, wherein: 2. An inner core ball having a rubber base as a main material and having a diameter of 2
2. The multi-piece solid golf ball according to claim 1, having a core diameter of 0 to 37 mm and a core diameter of 32 to 41 mm. 3. The thickness of the outer layer of the cover is 0.3 to 3.0 m.
m, the thickness of the inner layer of the cover is 0.5 to 3.0 mm,
3. The multi-piece solid golf ball according to claim 1, wherein the hardness difference between the outer layer and the inner layer is 5 or more in Shore D. 4. The multi-piece solid golf ball according to claim 1, wherein the inner layer hardness of the cover is higher than the outer layer hardness.