JP4431371B2 - Multi-piece solid golf ball - Google Patents

Description

  The present invention relates to a multi-piece solid golf ball in which a solid core having an inner layer, an intermediate layer, and an outer layer is covered with a cover.

  Two-piece solid golf balls with a cover made of thermoplastic resin on the outside of a hard, highly repulsive core formed from a rubber composition that is made of polybutadiene and zinc acrylate are blended. It has the advantage of having better flight distance performance than a so-called thread-wound golf ball in which a cover is coated on the outer side of a thread-wound core around which is wound, and is widely used. However, the two-piece solid golf ball has a problem that the impact felt by the player at the time of hitting is relatively strong (the hit feeling is not soft).

  Therefore, in recent years, a golf ball in which a soft intermediate layer is interposed between the core and the cover, or a golf ball in which at least one of the core and the cover has a multi-layer structure, and one layer thereof is formed of a soft material. That is, so-called multi-piece solid golf balls are being developed.

  For example, Patent Document 1 includes a center (core), an intermediate layer composed of two layers, an inner layer and an outer layer, and a cover, and among these four layers, four-piece solid golf having the highest inner layer hardness in the intermediate layer. A ball has been proposed. As a specific example of the material for forming the inner layer, an ionomer resin is disclosed.

Japanese Patent Laid-Open No. 10-179797

  However, when a layer made of an ionomer resin is provided as in Patent Document 1 or a layer made of a thermoplastic elastomer is provided, the resilience may be reduced by the layer. Performance may be degraded.

  That is, in the multi-piece solid golf ball according to the prior art, although it is possible to soften the hit feeling to some extent, there is a problem that the flight distance performance may be deteriorated.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a multi-piece solid golf ball having excellent flight distance performance while ensuring a soft feel at impact.

In order to achieve the above object, the present invention comprises an inner layer, one or two intermediate layers, and a solid core having an outer layer in this order from the inside, and a cover that covers the outer layer of the solid core. In a multi-piece solid golf ball that
When one of the layers forming the intermediate layer is an A layer, the A layer is made of a thermoplastic resin and has a Shore D hardness of 33 to 45 ,
The outer layer is made of a rubber composition and has a Shore D hardness of 40 to 57 ,
When the Shore D hardness of the A layer is HD2 and the Shore D hardness of the outer layer is HD3, 3 ≦ (HD3−HD2) ≦ 24 is satisfied.

Here, the A layer does not refer to a specific layer, but refers to a layer covering an inner layer in a layer forming the intermediate layer. For example, when the intermediate layer has a two- layer structure, the inner layer may be an A layer. In other words, a layer made of a thermoplastic resin and having a Shore D hardness of 20 to 47 may be used. Further, when the intermediate layer has a single layer structure, the intermediate layer itself is formed as the A layer.

  In this way, one of the layers forming the intermediate layer (A layer) is formed of a thermoplastic resin, and the Shore D hardness HD2 and HD3 of the A layer and the outer layer are set within a predetermined range, By establishing a relationship of 3 ≦ (HD3−HD2) ≦ 30 between the Shore D hardness HD2 of the A layer and the Shore D hardness HD3 of the outer layer, it is possible to ensure resilience and consequently flight distance performance, A golf ball having a soft feel at impact can be configured. In other words, a multi-piece solid golf ball having excellent flight distance performance and a soft feel at impact can be obtained.

  In this case, it is preferable that −15 ≦ (HD2−HD1) ≦ 30 holds when the inner layer is made of a rubber composition and the Shore D hardness of the inner layer is HD1. Thereby, it is possible to reliably obtain a multi-piece solid golf ball having excellent flight distance performance and a soft feel at impact.

  Also, in order to improve the flight performance of the multi-piece solid golf ball and soften the feel at impact, the inner layer diameter is 15 to 27 mm, the A layer thickness is 0.8 to 3 mm, and the outer layer thickness is 2 to 7 mm. It is preferable to set. For the same reason, the cover preferably has a Shore D hardness of 60 or more and a thickness of 1 to 3 mm.

  Preferable examples of the thermoplastic resin forming the A layer include polyamide-based thermoplastic elastomers. Another suitable example includes a mixture of a polyamide-based thermoplastic elastomer and at least one of a polyester-based thermoplastic elastomer or a silicone-modified thermoplastic elastomer.

Further, when the intermediate layer has a two-layer structure, the outer layer (B layer) covering the A layer has a Shore D hardness to improve the flight distance performance of the multi-piece solid golf ball and soften the shot feeling. It is preferable that the A layer has a Shore D hardness or less.

  In any case, HD1 ≦ HD2 is established between the Shore D hardness HD1 of the inner layer and the Shore D hardness HD2 of the A layer, and between HD1 and the Shore D hardness HD3 of the outer layer (HD3-HD1) It is preferable that ≧ 23 holds. By setting the Shore D hardness between the respective layers in this way, a multi-piece solid golf ball can be reliably obtained that can provide a soft shot feeling while ensuring excellent flight distance performance.

According to the present invention, the layer covering the inner layer in the layer forming the intermediate layer is formed of a thermoplastic resin, and the Shore D hardness of the layer is set within a predetermined range, and the Shore D of the layer is set. The outer layer Shore D hardness is set so that a predetermined mathematical formula is satisfied between the hardness and the outer layer Shore D hardness. For this reason, it can be set as the multi-piece solid golf ball which is excellent in the flight distance performance and can obtain a soft feel at impact.

  Hereinafter, preferred embodiments of the golf ball according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic longitudinal sectional view of a multi-piece solid golf ball according to the present embodiment. The multi-piece solid golf ball 10 includes a solid core 12 and a cover 14 that covers the solid core 12. Among these, the solid core 12 has a four-layer structure in which four layers of an inner layer 16, a first intermediate layer 18, a second intermediate layer 20, and an outer layer 22 are laminated in this order from the inside.

  In this case, among the four layers constituting the solid core 12, the inner layer 16, the second intermediate layer 20, and the outer layer 22 are formed from a rubber composition in which a base rubber is blended with a co-crosslinking agent, a crosslinking initiator, and a filler. Is done.

  Preferable examples of the base rubber include polybutadiene containing 80% or more of cis-1,4 structure. Examples of the co-crosslinking agent for crosslinking such a base rubber include zinc salts of unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and examples of the crosslinking initiator include dicumyl peroxide, 1,1. -Bis (t-butylperoxy) 3,3,5-trimethylcyclohexane and the like are exemplified. Examples of the filler include zinc oxide and barium sulfate. You may mix | blend an anti-aging agent, a coloring agent, etc. further as needed.

  On the other hand, the 1st intermediate | middle layer 18 which coat | covers the inner layer 16 is formed from the thermoplastic resin. Preferable examples of the thermoplastic resin include polyamide-based thermoplastic elastomers, polyester-based thermoplastic elastomers, silicone-modified thermoplastic elastomers, and mixtures of two or more thereof. In particular, when the first intermediate layer 18 is made of a polyamide-based thermoplastic elastomer alone, it is preferable because flight distance performance can be sufficiently secured. Alternatively, it may be a mixture of at least one of a polyamide-based thermoplastic elastomer and a polyester-based thermoplastic elastomer or a silicone-modified thermoplastic elastomer.

  The silicone-modified thermoplastic elastomer can be easily synthesized using an organic polysiloxane having a hydroxyl group at the terminal, an isocyanate compound, and a chain extender. In this case, aromatic isocyanate or aliphatic isocyanate may be used as the isocyanate compound, while high molecular diols such as polyether diol and polyester diol may be used as the chain extender.

  In addition to the above thermoplastic resin, the first intermediate layer 18 may contain a filler, an antioxidant, a colorant, and the like as necessary.

  Here, the Shore D hardnesses HD1, HD2, and HD3 of the inner layer 16, the first intermediate layer 18, and the outer layer 22 are set as follows.

  First, the Shore D hardness HD2 of the first intermediate layer 18 is set to 20 to 47. If it is less than 20, the flight distance performance of the multi-piece solid golf ball 10 is lowered. On the other hand, if it exceeds 47, the shot feeling becomes hard. A more preferable range of HD2 is 33-45.

  Next, the Shore D hardness HD3 of the outer layer 22 is set to 30-60. If it is less than 30, the flight distance performance of the multi-piece solid golf ball 10 is lowered. Moreover, when it exceeds 60, a shot feeling will become hard. A more preferable range of HD3 is 40-57.

  A relationship of 3 ≦ (HD3−HD2) ≦ 30 is established between HD2 and HD3. By making HD3 and HD2 within the above-mentioned range and making the difference between them within such a range, the multi-piece solid golf ball 10 exhibits excellent flight distance performance and a soft feel at impact is obtained. Become. The difference between HD3 and HD2 is more preferably 5 or more and 25 or less.

  Furthermore, it is preferable that a relationship of −15 ≦ (HD2−HD1) ≦ 30 is established between HD1 and HD2. Thereby, the multi-piece solid golf ball 10 which can obtain a soft shot feeling while ensuring excellent flight distance performance can be reliably obtained.

  As understood from the above formula, HD1 may be larger or smaller than HD2 and is not particularly limited. However, when HD1 is equal to or lower than HD2 and (HD3-HD1) ≧ 23 is satisfied, the flight distance performance is further improved, which is preferable. The difference between HD3 and HD1 is more preferably 25 or more.

  As described above, in the present embodiment, the first intermediate layer 18 that covers the inner layer 16 is formed of a thermoplastic resin, and the Shore D hardness HD1, HD2, and the inner layer 16, the first intermediate layer 18, and the outer layer 22 are HD3 is set within a predetermined numerical range or a range satisfying a predetermined mathematical expression. Therefore, it is possible to obtain the multi-piece solid golf ball 10 that has excellent flight distance performance and a soft feel at impact.

  Here, if the Shore D hardness of the second intermediate layer 20 is HD4, the numerical range of HD4 is not particularly limited, but the multi-piece solid golf ball 10 exhibits excellent flight distance performance and feels at impact. In order to soften, it is preferable to set HD4 to be the Shore D hardness HD2 or less of the first intermediate layer 18.

  In order to obtain the multi-piece solid golf ball 10 having excellent flight distance performance and soft feel at impact, the inner layer 16 has a diameter of 15 to 27 mm, the first intermediate layer 18 has a thickness of 0.8 to 3 mm, and the outer layer. It is preferable to set the thickness of 22 to 2 to 7 mm.

  The cover 14 covering the solid core 12 formed as described above can be formed from, for example, an ionomer resin. You may make it mix | blend a filler, antioxidant, a coloring agent, a fluorescent whitening agent, etc. as needed. In the cover 14, in order to develop the excellent flight distance performance in the multi-piece solid golf ball 10 and soften the shot feeling, a suitable Shore D hardness is 60 or more, and a suitable thickness is 1 to 3 mm. .

  In the above-described embodiment, the intermediate layer is formed by two layers of the first intermediate layer 18 and the second intermediate layer 20, but the intermediate layer 24 having a single-layer structure as shown in FIG. Good. In this case, the intermediate layer 24 is formed of a thermoplastic resin, the Shore D hardness is set to 20 to 47, and 3 ≦ (HD3−HD2) ≦ 30, more preferably between the Shore D hardness HD3 of the outer layer 22. May satisfy the relationship of 5 ≦ (HD3−HD2) ≦ 25.

  In the embodiment shown in FIG. 1, the first intermediate layer 18 covering the inner layer 16 is formed of a thermoplastic resin, the Shore D hardness is set to 20 to 47, and the Shore D hardness HD3 of the outer layer 22 is 3 ≦ (HD3−HD2) ≦ 30 is established between the two, but instead of this, the second intermediate layer 20 is formed of a thermoplastic resin and its Shore D hardness (HD2) is 20 to 20 47 and the relationship of 3 ≦ (HD3−HD2) ≦ 30 may be established between the outer layer 22 and the Shore D hardness HD3. In this case, the Shore D hardness of the first intermediate layer 18 is not particularly limited, but is preferably equal to or higher than the Shore D hardness (HD2) of the second intermediate layer 20. That is, in the present invention, when the intermediate layer has a multilayer structure, it is sufficient that at least one layer satisfies the above conditions.

  Polybutadiene rubber, zinc acrylate, zinc oxide, anti-aging agent, dicumyl peroxide as a crosslinking agent are mixed in the proportions shown in FIG. 3 (numbers are weight ratios, the same applies hereinafter), and the kneaded rubber composition is mixed in the mold The inner layer 16 was produced by compression molding while heating at 160 ° C. for about 20 minutes.

  Next, Pebax MX 1205 (trade name, polyamide-based thermoplastic elastomer manufactured by Atchem Co.) was injection-molded on the inner layer 16 to form the first intermediate layer 18.

  Next, the same components as the inner layer 16 are mixed at a ratio shown in FIG. 3 to form a rubber composition. After the first intermediate layer 18 is coated with the rubber composition, heating and compression molding is performed in the same manner as the inner layer 16. A second intermediate layer 20 was provided.

  Next, the same components as those of the inner layer 16 are mixed at a ratio shown in FIG. 3 to form a rubber composition. -The outer layer 22 was formed by compression molding. As a result, a solid core 12 having a four-layer structure was obtained.

  Finally, an ionomer resin was injection-molded on the outer layer 22 to form a cover 14 to obtain a multi-piece solid golf ball 10 having a solid core 12 having four layers and a cover 14. This is Example 1.

  Example 1 except that the first intermediate layer 18 was formed from a 95: 5 mixture of Pebax MX1205 and X22-2335N (trade name, silicone-modified thermoplastic elastomer manufactured by Shin-Etsu Chemical Co., Ltd.). Thus, a multi-piece solid golf ball 10 was produced. This is Example 2.

  The first intermediate layer 18 is made from a 50:50 mixture of Pebax 3533 (trade name, polyamide-based thermoplastic elastomer manufactured by Atchem) and Hytrel 4047 (trade name, polyester-based thermoplastic elastomer manufactured by Toray DuPont). A multi-piece solid golf ball 10 was produced in the same manner as in Example 1 except that it was formed. This is Example 3.

  In the same manner as in Example 2, the inner layer 16 and the intermediate layer 24 were produced. Next, the intermediate layer 24 was covered with the rubber composition in which the raw materials were mixed in the ratio shown in FIG. As a result, a solid core 12 having a three-layer structure was obtained.

  Finally, a cover 14 made of an ionomer resin was provided in the same manner as in Example 2. As a result, a multi-piece solid golf ball 10 including a solid core 12 having three layers and a cover 14 was obtained. This is Example 4.

Comparative Example 1

  A solid consisting of three layers in the same manner as in Example 4 except that an intermediate layer having a ratio of X22-2335N, Pebax 3533, and Hytrel 4047 of 5:30:70 and a Shore D hardness of 48 was provided. A multi-piece solid golf ball having a core and a cover was obtained. This is referred to as Comparative Example 1.

  Then, the multi-piece solid golf balls of Examples 1 to 4 and Comparative Example 1 manufactured as described above were each hit, the initial velocity of the ball at the time of hitting was measured, and the hit feeling was examined. Here, the initial velocity was measured in accordance with an initial velocity test method defined by the American Golf Association, and the relative velocity was determined by setting the initial velocity of the golf ball of Comparative Example 1 to 100, and was used as a rebound index. The larger the rebound index, the higher the rebound, and the better the initial velocity when hit, and thus the better the flight distance performance. Also, the feel at impact is an evaluation by actual hitting of a male senior golfer using a No. 1 wood club, an No. 8 iron club, or a putter.

  The rebound index and feel at impact are shown in FIG. 4 together with various physical properties such as the diameter or thickness of each layer and Shore D hardness in the multi-piece solid golf balls of Examples 1 to 4 and Comparative Example 1. Here, regarding the feel at impact in FIG. 4, “は” represents “very soft”, “◯” represents “soft”, “Δ” represents “normal”, and “×” represents “hard”.

  From FIG. 4, each multi-piece solid golf ball 10 of Examples 1 to 4 has a rebound index and consequently an initial velocity that are significantly higher than those of the multi-piece solid golf ball of Comparative Example 1, and a softer feel at impact. Is clearly obtained.

1 is a schematic cross-sectional view of a multi-piece solid golf ball according to an embodiment. It is a schematic sectional drawing of the multi-piece solid golf ball concerning another embodiment. 4 is a chart showing ingredients and mixing ratios of raw materials for each layer in each multi-piece solid golf ball of Examples 1 to 4 and Comparative Example 1; 4 is a chart showing physical properties and evaluation results of each layer in each multi-piece solid golf ball of Examples 1 to 4 and Comparative Example 1;

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Multi-piece solid golf ball 12 ... Solid core 14 ... Cover 16 ... Inner layer 18 ... 1st intermediate | middle layer 20 ... 2nd intermediate | middle layer 22 ... Outer layer 24 ... Intermediate | middle layer

Claims (5)

In a multi-piece solid golf ball comprising a solid core having an inner layer, two intermediate layers, and an outer layer in this order from the inside, and a cover covering the outer layer of the solid core,
When the inner layer of the two layers forming the intermediate layer is the A layer and the outer layer covering the A layer is the B layer, the A layer is made of a thermoplastic resin and has a Shore D hardness of 33 to 45. And
The Shore D hardness of the B layer is less than or equal to the Shore D hardness of the A layer,
The outer layer is made of a rubber composition and has a Shore D hardness of 40 to 57,
When the Shore D hardness of the A layer is HD2 and the Shore D hardness of the outer layer is HD3, 3 ≦ (HD3−HD2) ≦ 24 holds,
The multi-piece solid golf ball, wherein the cover has a Shore D hardness of 60 or more and a thickness of 1 to 3 mm.   The golf ball according to claim 1, wherein the inner layer is made of a rubber composition, and when the Shore D hardness of the inner layer is HD1, −15 ≦ (HD2−HD1) ≦ 30 is satisfied. Peace solid golf ball.   3. The golf ball according to claim 1, wherein the inner layer has a diameter of 15 to 27 mm, the A layer has a thickness of 0.8 to 3 mm, and the outer layer has a thickness of 2 to 7 mm. Golf ball.   4. The multi-piece solid golf ball according to claim 1, wherein the thermoplastic resin forming the A layer is a polyamide-based thermoplastic elastomer. 5.   4. The golf ball according to claim 1, wherein the thermoplastic resin forming the layer A is at least one of a polyamide-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, or a silicone-modified thermoplastic elastomer. 5. A multi-piece solid golf ball characterized by being a mixture with either of them.

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