JPH10328325A - Multi-piece solid golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shooting feeling which is soft and has a clicking feeling at the time of a full shot by a driver while keeping a high repulsion, and at the same time, provide an excellent spinning performance at the time of an approach shot by a short iron club such as a sandwedge 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 code 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 formed to be 55-70 by the Shore D, and the surface hardness of the surrounding layer 4 is lower than the surface hardness of the inner core ball 3 by the Shore D, and the hardness of the inner core ball 3 is 1.5-4.5 mm by a deformation amount when a load of 100 kg is loaded, and a ratio of the inner core ball hardness A and the ball hardness B is 0.4<=A/B<=1.8 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, while maintaining high resilience at the time of a full shot with a driver, a soft and clicking feel can be obtained, and a spin performance and approach shot at the time of approach shot with short iron such as sand wedge and The present invention relates to a multi-piece solid golf ball having an excellent feel when putting.

[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 middle layer improve the hit feeling with the driver, but the click feeling is not obtained, and the cover is hard, so the hit feeling on approach shots is hard, and the spin is not applied enough to control It is inferior in sex. However, since the core which has the greatest influence on resilience is soft, resilience is insufficient and the flight distance on a driver hit is not sufficient. The driver feels softer, but lacks the click feeling required by advanced users due to its softness "without a core". Therefore, further improvements and developments have been desired.

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. In the ball, while maintaining high resilience at the time of a full shot with the driver, a good hit feeling with a soft and click feeling is obtained, and the spin performance at the approach shot with a short iron such as a sand wedge and at the time of approach shot and putting It is an object of the present invention to provide a multi-piece solid golf ball excellent in 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 the cover covering the core comprises an outer layer and an inner layer, a core comprising a relatively hard inner core ball and a relatively soft surrounding layer is covered with a cover comprising a soft outer layer and a hard inner layer. By forming a four-layer structure, the outer layer of the cover formed softly improves the spin performance at the time of approach shot with a short iron such as a sand wedge, and the hit feeling at the time of approach shot and putting becomes soft, By using a hard resin with good resilience for the inner layer of the cover, it is possible to maintain good flight performance. Comparatively hard to form, by coating the relatively soft envelope layer around it, while maintaining the high resilience full shot at with a driver, good to feel can be obtained with a soft and click feeling,
Were found 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 a solid golf ball, the outer layer hardness of the cover is 40 to 60 on Shore D, the inner layer hardness of the cover is 55 to 70 on Shore D, and the surface hardness of the surrounding layer is the surface of the inner core ball on Shore D. The hardness of the inner core ball is 1.5 to 4.5 mm in the deformation amount under a load of 100 kg, and the ratio of the inner ball hardness A to the ball hardness B is the deformation amount under a load of 100 kg. By forming 0.4 ≦ A / B ≦ 1.8,
The ability to effectively solve the problems of conventional three-piece solid golf balls, that is, while maintaining high resilience during a full shot with a driver, the flight distance is dramatically increased by an appropriate amount of spin, making it soft and professional. Excellent hit feeling with a "core" click feeling required by advanced users such as, etc., and excellent spin performance on approach shots with short irons such as sand wedges and excellent hit feeling on approach shots and putting Finding that a multi-piece solid golf ball can be obtained,
The present invention has been completed.

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.
The surface hardness of the surrounding layer is lower than the surface hardness of the inner sphere at Shore D, and the hardness of the inner sphere is 1.5 to 4.5 mm in a deformation amount under a load of 100 kg. The ratio between the inner core ball hardness A and the ball hardness B is 100
a multi-piece solid golf ball, wherein the deformation amount under a load of kg satisfies 0.4 ≦ A / B ≦ 1.8, (2) the inner core ball is mainly composed of a rubber base material and has a diameter of 20 ~
The multi-piece solid golf ball according to (1), wherein the golf ball has a core diameter of 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 mm, the thickness of the inner layer of the cover is 0.5 to 3.0 mm, and the difference in hardness between the outer layer and the inner layer is 5 or more in Shore D. The multi-piece solid golf ball according to (1) or (2), and (4) the multi-piece solid golf ball according to (1), (2) or (3), wherein the inner layer hardness of the cover is higher than the outer layer hardness. I will provide a.

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.

[0010] The hardness of the inner core ball 3 constituting the core 2 of the golf ball 1 of the present invention is 1.5 to 4.5 mm, more preferably 1.8 to 4.5 mm in a deformation amount under a load of 100 kg.
4.2 mm. If the deformation amount is less than 1.5 mm, the core becomes too hard, and the hit feeling becomes hard. On the other hand, if it exceeds 4.5 mm, the core becomes too soft, the resilience decreases, and a click feeling cannot be obtained. The surface hardness of the inner sphere is
It is preferably from 40 to 70, more preferably from 42 to 65, as measured by a Shore D hardness meter (hereinafter referred to as Shore D). Here, the surface hardness of the inner core sphere indicates the hardness of the surface of the inner core sphere, and is an average value measured at five points.

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 20 to 55, more preferably 25 to 50, and the surrounding layer has a surface hardness of the inner core sphere. It is necessary that the hardness is lower than the surface hardness. Specifically, Shore D is preferably 5 to 50, and more preferably 7 to
It is formed 40 lower. If the surface hardness of the surrounding layer is higher than the surface hardness of the inner core sphere, it is not possible to obtain a soft and clicking feel while maintaining the resilience during a full shot with a driver. The definition and measurement method of the surface hardness of the surrounding layer are the same as those in the case of 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. Point.

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 not particularly limited, and may be formed mainly of a rubber base material as in the case of the inner core sphere, or may be formed mainly of a thermoplastic resin. In this case, as the thermoplastic resin, for example, Hytrel 400
Polyester-based thermoplastic elastomers such as Nos. 1 and 3078 (manufactured by Dupont Toray) and ionomer resins such as Himilan (manufactured by Dupont Mitsui Polychemicals), Surlyn (manufactured by Dupont, USA), and the like. May be used alone or in combination of two or more. 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 sphere is covered with a half cup and heated and pressed under a predetermined condition is adopted. On the other hand, when the surrounding layer is a thermoplastic resin, the composition for the molten surrounding layer is injected by injection molding. A method of coating around the sphere is adopted.

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
Shore D: 55-70, preferably 55-67.
If the hardness of the inner layer is less than 55, the resilience may be too low, and if it is more than 70, the hit feeling becomes hard. Further, the hardness of the inner layer of the cover is preferably higher than the hardness of the outer layer, 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 which is hard and excellent in resilience is preferable, and a commercially available ionomer resin such as Himilan 1605, 1706, 1557, 1856 (manufactured by DuPont-Mitsui Polychemicals) is preferable, and other resins such as polyester, polyamide and polyurethane are preferable. Thermoplastic resins and the like,
One of these can be used alone, or two or more can be used in combination.

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 polyamide, polyester, 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, and the core may be wrapped in two half-cups which have been previously formed into a half-shell sphere and heated and pressed, or the cover composition may be coated with the cover composition. The periphery may be injection molded.

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 of the hardness A of the inner core ball to the hardness B of the golf ball is 0.4% in the amount of deformation under a load of 100 kg.
≦ A / B ≦ 1.8, preferably 0.6 ≦ A / B ≦
1.6. If A / B is less than 0.4, the ball is too soft and the resilience decreases, and if it exceeds 1.8, 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 structure, the golf ball of the present invention maintains a high resilience at the time of a full shot with a driver, has an appropriate spin amount, and increases the flight distance.
The softness of the "core" provides a good hit feeling with the click feeling especially demanded by professionals, while the spin is good on approach shots with sand wedges and putters, and it has excellent controllability. And has a soft and good hit feeling.

[0029]

According to the present invention, a soft and clicking feel can be obtained while maintaining high resilience at the time of a full shot with a driver, and a spin performance at the time of approach shot with a short iron such as a sand wedge. It is also excellent in 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] The inner core sphere compositions having the formulations shown in Tables 1 and 2 were kneaded using a kneading roll, and then vulcanized at 155 ° C for 15 minutes in a mold. Was prepared. If the surrounding layer is a rubber member on this inner core sphere,
The rubber compositions having the formulations shown in Tables 1 and 2 are kneaded with a kneading roll, molded in a half-cup shape in a semi-vulcanized state, and the inner core sphere is covered with the pair of half cups, and 155 is again formed.
A core was obtained by pressing at 15 ° C. for 15 minutes (Examples 1 to 3, Comparative Example 3). On the other hand, when the envelope layer is made of a thermoplastic resin, Table 1
The composition of the surrounding layer was injection-molded around the inner core sphere according to the formula (1) to obtain cores (Examples 4 to 7).

The cover inner layer and the outer layer prepared according to the formulations shown in Tables 1 and 2 were sequentially injection-molded on the obtained core to obtain golf balls having a four-layer structure of Examples 1 to 7 and Comparative Example 3. Was. Comparative Example 4 is a two-piece golf ball having a core and a single-layer cover, and Comparative Examples 1 and 2 are a three-piece golf ball having a single-layer core without an enclosing layer and an inner layer and an outer layer of a cover. The blending amounts shown in Tables 1 and 2 are all parts by weight, and the ratios are as follows: inner sphere, surrounding layer, inner cover layer,
It is independent in each outer layer.

[0033]

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

[0034]

[Table 2]

Next, the flying performance and the hit feeling of the obtained golf ball were measured according to the following methods. The results are shown in Tables 3 and 4.

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))
The amount of spin, the fall distance (carry), and the reach distance (total) when shot at / sec (HS50) were measured. In addition, sand wedge (J's Classica)
l Edition (Bridgestone Sports Co., Ltd .; #SW) at a head speed of 20 m / sec (H
The spin rate at the time of the shot in S20) was measured.

A head speed of about 50 m by a hit driver (# W1)
The feeling when five professionals actually hit at / sec (HS50) was evaluated according to the following criteria. ◎: Soft and click feeling ○: Soft but unreliable touch without click feeling ×: Hard In addition, when five professionals hit with a sand wedge (#SW) at a head speed of about 20 m / sec (HS20) Was evaluated according to the following criteria. ○: soft ×: hard

[0038]

[Table 3] * 4: Deformation amount under 100 kg load (mm)

[0039]

[Table 4]

From the results shown in Tables 3 and 4, Comparative Example 1 is a three-piece golf ball of the same type as that described in Japanese Patent Application Laid-Open No. 7-24084, in which the driver was used because the core and the intermediate layer (inner layer cover) were soft. Is soft, but there is no click feeling, and the cover is hard, so that the sand wedge has a hard feel and spin is not sufficiently applied. Comparative Example 2 is a three-piece golf ball of the same type as that described in Japanese Patent Application Laid-Open No. Hei 7-24085, in which the core is soft, so that the hit feeling with a driver is soft, but there is no click feeling. Both are soft, have insufficient rebound, and do not travel a short distance. Comparative Example 3 is a golf ball having a four-layer structure of the same type as that of the present application, and has a good hit feeling with a driver.
Although the flight distance also increases, the hit feeling of the sand wedge is hard because the outer layer cover is hard, and spin is not sufficiently applied. Comparative Example 4 is a general spin-type two-piece golf ball having a spin performance with a sand wedge,
The hit feeling is excellent, but the core is hard and the cover is single layer and soft, so that the hit feeling with a driver is hard, and 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 by a driver's full shot, a soft and clicking feel is obtained, and the approach shot with a sand wedge is soft. It has a hit feeling and good spin performance.

[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 inner layer hardness of the cover is formed to 55 to 70 by Shore D, the surface hardness of the surrounding layer is lower than the surface hardness of inner core ball at Shore D, and the hardness of the inner core ball is 100 kg. The deformation amount under load is 1.5 to 4.5 mm, and the ratio of the inner core ball hardness A to the ball hardness B is 0.4 ≦ A / B ≦ 1.8 at a deformation amount under a load of 100 kg. A multi-piece solid golf ball, characterized in that: 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.