JP3956069B2 - Multi-piece solid golf ball - Google Patents

Description

【００４１】
得られたソリッドコアを金型内に配備し、表２，３に示す内層カバー材を射出して、内層カバーを形成した後、金型から取り出して該内層カバーの表面をバレル研磨にて粗面化した。
【００４２】
上記粗面化したコアを金型内に配備し、表２，３に示す外層カバー材を射出し、総数４３２個、表面占有率７０％、体積率（ディンプル部分を考慮しないボールの仮想球体積に対するディンプル総容積の割合）０．９％のディンプルを有するマルチピースソリッドゴルフボールを作成した。
【００４３】
また、比較例１は、表１のソリッドコアに表３で示されるカバー材を１層被覆形成してなるツーピースソリッドゴルフボールであり、ディンプル個数及び態様は上記と同様である。
【００４４】
製造した各ソリッドゴルフボールに対して、下記方法により、飛び性能、スピン性能、コントロール性、耐擦過傷性、繰り返し打撃耐久性を評価した。結果を表２，３に併記する。なお、表中、中間ボールとはソリッドコアに内層カバーを形成したものを示す。
【００４５】
飛び性能
ツルー・テンパー（Ｔｒｕｅ Ｔｅｍｐｅｒ）社製のスウィングロボットを用い、ドライバーを用いてヘッドスピード５０ｍ／ｓｅｃ（ＨＳ＝５０）でショットしたときのスピン量、初速度、キャリー、トータル飛距離を測定した。
スピン性能
上記と同様のスウィングロボットにて、ピッチングウェッジを用いて、ヘッドスピード２０ｍ／ｓｅｃ（ＨＳ＝２０）でショットした時のスピン量を測定した。
コントロール性
上級アマチュアプレーヤー（いわゆるシングルプレーヤー）１０人により、ピッチングウェッジを用いてアプローチショットを行った時のコントロール性を下記基準にて官能評価した。
○：大変優れる
△：良好
×：悪い
耐擦過傷性
飛び性能と同様のスウィングロボットにて、ピッチングウェッジを用いて、ヘッドスピード３０ｍ／ｓｅｃ（ＨＳ＝３０）で、同一ボールにつき３回繰り返し打撃した後にボールの表面状態を目視にて観察し、１０段階で点数評価した（点数が高い程良好であることを示す）。
繰り返し打撃耐久性
飛び性能と同様のスウィングロボットにて、ドライバーを用いて、ヘッドスピード４５ｍ／ｓｅｃ（ＨＳ＝４５）で、同一ボールにつき３００回繰り返し打撃した後、ボールの状態を目視にて観察し、比較例１を基準値１００とした場合における各ボールの状態を比較評価した。
【００４６】
【表２】

【００４７】
【表３】

１）デュポン社製，酸含量１８％，亜鉛系アイオノマー（Ｄ６５）
２）デュポン社製，酸含量１８％，ナトリウム系アイオノマー（Ｄ６６）
３）デュポン社製，酸含量２０％，亜鉛系アイオノマー（Ｄ６７）
４）デュポン社製，酸含量２０％，ナトリウム系アイオノマー（Ｄ６８）
５）三井・デュポンポリケミカル社製，酸含量１５％，亜鉛系アイオノマー（Ｄ６２）
６）三井・デュポンポリケミカル社製，酸含量１５％，ナトリウム系アイオノマー（Ｄ６３）
７）住友化学工業社製，エチレン−グリシジルメタクリレート共重合体，
ＧＭＡ含量６重量％
８）三井・デュポンポリケミカル社製，エチレン−エチルアクリレートの無水マレイン酸グラフト変性物
９）エクソン社製，エチレン−メタアクリレート−アクリル酸三元共重合体
１０）東レ・デュポン社製，ポリエステルエラストマー（Ｄ４０）
１１）アトケム社製，ポリアミドエラストマー（Ｄ４０）
１２）大日本インキ化学工業社製，ポリウレタンエラストマー（Ｄ４０）
＊（Ｄ）はショアＤ硬度を示す。
１３）１００ｋｇ荷重負荷時のボールの変形量
１４）ゴルフボール公認機関（ＵＳＧＡ）の測定法に基づいて測定した初速度
【００４８】
本発明のマルチピースソリッドゴルフボールは、オレフィン系化合物にグリシジルメタクリレート又は有機酸をグラフト共重合又はランダム共重合させた重合体が外層カバー材に配合されているので、内層及び外層カバーが強固に接着しており、アプローチショット時のスピン量が多く、ドライバーショット時のスピン量が少なく、コントロール性に優れ、かつ飛距離の増大化が図れる優れたスピン量を有する上、アイアンショットに対する擦過傷が発生しにくく、繰り返し打撃耐久性に優れたものであることが認められた。
【００４９】
これに対して、比較例１のツーピースソリッドゴルフボールは、ドライバー、アイアンショット時におけるスピン性能が少なすぎ、コントロール性が悪く、耐久性が劣るもので、また比較例２〜４のいずれのカバー材にも上記共重合体を配合していないスリーピースソリッドゴルフボールは、耐久性及び耐擦過傷性が極端に劣るものであった。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multi-piece solid golf ball that is excellent in durability against repeated hitting, can increase a flight distance, and has excellent controllability and scratch resistance.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, for low-handy players, the spin control performance of the ball when shot with a short iron has been important, especially for the two-piece golf ball made of ionomer resin with a hard cover, excellent flying distance unique to the ball Improving spin control performance without compromising performance is a major issue in development, and various studies have been conducted.
[0003]
For example, US Pat. No. 4,431,193 discloses a three-piece solid golf ball in which an inner layer cover is formed of a hard ionomer resin and an outer layer cover is formed of a soft ionomer resin, thereby improving the respective spin amounts when shot with a driver and a short iron. It has been proposed to plan.
[0004]
However, since this golf ball is inferior to conventional two-piece solid golf balls in abrasion resistance and flight distance performance, improvements have been demanded.
[0005]
JP-A-6-343718 discloses a heat which does not contain a low modulus ionomer resin or an ionomer resin having a relatively low acid content while forming an inner layer cover with a high modulus ionomer resin having a relatively high acid content. A three-piece solid golf ball made of a plastic elastomer has been proposed.
[0006]
However, this golf ball has a problem that when the outer layer cover is formed of a thermoplastic elastomer resin, the rebound and durability of the ball may be significantly impaired due to poor adhesion of the inner layer cover to the ionomer resin. ing.
[0007]
The present invention has been made in view of the above circumstances, and has excellent flight distance performance over conventional two-piece solid golf balls, and is resistant to repeated hitting, such as controllability with a short iron, spin performance, abrasion resistance, etc. An object of the present invention is to provide a multi-piece solid golf ball capable of improving playability.
[0008]
Means for Solving the Problem and Embodiment of the Invention
In order to achieve the above object, the present inventors
(1) In a multi-piece solid golf ball in which a solid core and a cover having a two-layer structure consisting of an inner layer and an outer layer are coated on the solid core, the inner layer cover contains at least 15% by weight of α, β-unsaturated carboxylic acid. The outer layer cover is composed mainly of one or more selected from polyurethane elastomer, polyester elastomer and polyamide elastomer, and does not contain an ionomer resin. A multi-piece solid golf ball comprising a material obtained by blending a polymer obtained by graft copolymerization or random copolymerization of glycidyl methacrylate or an organic acid with an olefin compound ,
(2) The multi-layer solid golf ball according to (1), wherein the inner layer cover has a Shore D hardness of 60 to 75 and the outer layer cover has a Shore D hardness of 35 to 55 , and (3) the olefinic compound described above A polymer obtained by graft copolymerization or random copolymerization of glycidyl methacrylate or an organic acid is an ethylene-glycidyl methacrylate copolymer, an ethylene-ethyl acrylate maleic anhydride graft-modified product, or an ethylene-methacrylate-acrylic acid terpolymer. (1) A multi-piece solid golf ball according to (1) is provided.
[0009]
That is, as a result of intensive studies on a golf ball in which a solid core and a cover having a two-layer structure composed of an inner layer and an outer layer are coated on the solid core, the inventors have determined the materials of the inner layer cover and the outer layer cover. In addition , the compatibility between the polymer and the cover material is obtained by blending a polymer obtained by graft copolymerization or random copolymerization of glycidyl methacrylate or organic acid with an olefin compound into the main material of the outer layer cover. It is good, and the adhesion between the inner cover and outer cover is strengthened, the durability by repeated hits is dramatically improved, the flying distance is increased by reducing the spin at the time of driver shot, short iron etc. It is said that the controllability can be improved by increasing the spin at the time of approach shot, and the scratch resistance is good. It was found that multi-piece solid golf ball is obtained having excellent properties.
[0010]
In order to further improve the performance of the multi-piece solid golf ball, it is possible to optimize the Shore D hardness of the inner layer and the outer layer cover, specify the main material of the outer layer cover, and specify the material of the adhesive. It has been found that it is more effective and has led to the present invention.
[0011]
Hereinafter, the present invention will be described in more detail. As described above, the multi-piece solid golf ball of the present invention is formed by covering a solid core and a cover having a two-layer structure of an inner layer and an outer layer on the solid core. .
[0012]
Here, the solid core will be described in detail. The solid core of the present invention can be formed using a known material, and a known rubber in which a base rubber is blended with a co-crosslinking agent, a peroxide, an inert filler, and the like. This rubber composition can be obtained by heating, pressing and molding.
[0013]
In this case, as the base rubber, polybutadiene conventionally used for solid cores or a mixture of polybutadiene and polyisoprene rubber can be used. In particular, in order to obtain high resilience, a cis structure 90 is used. It is preferable to use cis-1,4-polybutadiene having at least%.
[0014]
As the co-crosslinking agent, for example, zinc salts of unsaturated fatty acids such as methacrylic acid and acrylic acid, and ester compounds such as magnesium salts and trimethylpropane trimethacrylate can be used. Can be suitably used. The compounding amount of these co-crosslinking agents is not limited, but can be 10 to 50 parts by weight with respect to 100 parts by weight of the base rubber.
[0015]
As the peroxide, for example, dicumyl peroxide or a mixture of dicumyl peroxide and 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane is preferably used. The blending amount is preferably 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the base rubber.
[0016]
Examples of the inert filler include zinc white, barium sulfate, silica, calcium carbonate and zinc carbonate. In general, zinc white and barium sulfate are preferably used, and the blending amount thereof is appropriately adjusted. In particular, in order to improve the resilience of the solid core, it is recommended that the zinc white be blended so as to be 30% by weight or more of the total filler.
[0017]
Moreover, additives, such as anti-aging agent, can be added to the core material as necessary.
[0018]
In order to obtain a solid core with the above material, it can be produced according to a known method. After kneading using a kneader such as a Banbury mixer or a roll, the material is put into a core mold, and a co-crosslinking agent and It can be cured by heating to a temperature sufficient for the peroxide to act.
[0019]
The solid core of the present invention has a diameter of 30 to 41 mm, particularly 32 to 40 mm, a weight of 15 to 35 g, particularly 20 to 32 g, and a deformation amount of 2.5 to 5.5 mm, particularly 3.0 to 30 kg when loaded with 100 kg. It can be formed to be 5.0 mm.
[0020]
The inner layer cover of the present invention is mainly composed of an ionomer resin containing α, β-unsaturated carboxylic acid at a high concentration of 15% by weight or more.
[0021]
Here, examples of the α, β-unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid and fumaric acid, and methacrylic acid and acrylic acid are particularly preferable.
[0022]
The ionomer resin used as the inner layer cover material of the present invention is one in which the α, β-unsaturated carboxylic acid is contained in the resin at a high concentration of 15% by weight or more, and the content is particularly 15 to 25% by weight. It is recommended that the content be 17 to 25% by weight, and more preferably 18.5 to 21.5% by weight. If it is less than 15% by weight, the rigidity is low and the resilience is also poor. In addition, when it exceeds 25 weight%, rigidity may become high too much and resin may become fragile.
[0023]
As such an ionomer resin, specifically, Himiran 1706, 1605 (Mitsui / DuPont Polychemical), Surlyn 8220, AM7317, 7318, 7315 (DuPont), etc. can be used. Can be used alone or in admixture of two or more, but in particular, the combination of two or more ionomer resins with different neutralizing metal ions is recommended. As an example of the combination of neutralizing metal ions, Zn / Na, Mg / Li, Mg / Na and the like.
[0024]
In the present invention, the inner layer cover hardness is not particularly limited, but a Shore D hardness of 60 to 75, particularly a Shore D hardness of 62 to 72 is recommended. If the pitch is higher than 75, the shot feeling becomes very hard and the feeling may be worsened. The specific gravity of the inner layer cover is preferably 0.8 to 1.5.
[0025]
Moreover, the thickness of the inner layer cover can usually be formed to 0.5 to 3.0 mm, particularly 1.0 to 2.0 mm, and if it is thinner than 0.5 mm, the effect of controlling the deformation of the core and increasing the resilience If the thickness is larger than 3.0 mm, the resilience of the core may not be fully utilized.
[0026]
The outer layer cover of the present invention is mainly composed of a thermoplastic elastomer containing no ionomer resin , and the thermoplastic elastomer is selected from a polyurethane elastomer, a polyester elastomer and a polyamide elastomer . As these commercially available products, Hytrel 4047 (polyester elastomer manufactured by Toray DuPont), Pebax 4033SA00 (polyamide elastomer manufactured by Atchem), Pandex T7890 (polyurethane elastomer manufactured by Dainippon Ink and Chemicals, Inc.) and the like can be suitably used. These can be used alone or in combination of two or more. The specific gravity of the outer cover can usually be adjusted to 1.0 to 1.5.
[0027]
In the present invention, the hardness of the outer layer cover is not particularly limited, but the Shore D hardness is 35 to 55, particularly 45 to 55, and is preferably formed to have a lower hardness than the inner layer cover described above.
[0028]
Further, the thickness of the outer layer cover is not particularly limited, and can be generally 0.6 to 1.6 mm, particularly 0.8 to 1.6 mm. If the outer layer cover is too thin, If the ball is too thick, the resilience of the ball will be reduced and good flight performance may not be obtained.
[0029]
The golf ball of the present invention is formed by blending the outer cover material with a polymer obtained by graft copolymerization or random copolymerization of olefin compound with glycidyl methacrylate or organic acid.
[0030]
In this case, examples of the olefinic compound include ethylene, a mixture of ethylene and ethyl acrylate, methacrylate, and the like, and examples of the organic acid include maleic anhydride and acrylic acid. Specifically, ethylene-glycidyl methacrylate copolymer, ethylene-ethyl acrylate maleic anhydride graft-modified product, ethylene-methacrylate-acrylic acid terpolymer, and the like are commercially available. 2C (ethylene-glycidyl methacrylate copolymer manufactured by Sumitomo Chemical Co., Ltd.), AR-201 (methylene anhydride-modified maleic anhydride grafted product of Mitsui DuPont Polychemical), ESCOR-ATX325 (ethylene-meta manufactured by Exxon) Acrylate-acrylic acid terpolymers) and the like can be suitably used, and these may be used alone or in combination of two or more.
[0031]
In the present invention, the blending amount of the polymer obtained by graft copolymerization or random copolymerization of glycidyl methacrylate or organic acid with the olefin compound is not particularly limited, but the main material of the outer layer cover material is not limited. It is usually preferable to mix 5 to 50 parts by weight, particularly 10 to 30 parts by weight with respect to 100 parts by weight. By blending with the outer layer cover material, the adhesiveness between the inner layer cover and the outer layer cover becomes strong and good. High flight performance and durability. Therefore, if the blending amount with respect to the outer layer cover material is less than the above-mentioned amount, the inner / outer layer cover may be weakly bonded and the durability may be deteriorated. There is.
[0032]
The multi-piece solid golf ball of the present invention is obtained by forming each layer by a known method using the material of each layer described above on a solid core prepared in advance, and the formation method of each layer is not particularly limited. Without, for example, a method in which a solid core is arranged in a mold and an inner layer cover material and an outer layer cover material are sequentially injected and molded, a pair of hemispherical bowl-shaped half cups are created in advance with the inner layer and the outer layer cover material, A method of forming a pair of half cups by overlapping the half cups of the outer layer cover on the half cups of the inner layer cover, encapsulating the solid core with the half cups, and compression molding at 110 to 160 ° C. for 2 to 10 minutes, above Encapsulate the solid core with a pair of half cups formed only by the inner layer cover, compression molding at 110-160 ° C for 2-10 minutes After this, the outer layer cover material can be injection molded from above, and in order to form the outer layer cover more stably on the inner layer cover, the barrel is previously placed on the inner layer cover surface before coating the outer layer cover. It is recommended that the surface be roughened by polishing or the like.
[0033]
The total thickness of the inner layer cover and the outer layer cover formed as described above is usually 1.0 to 6.0 mm, particularly preferably 2.0 to 4.0 mm, and the inner layer cover as a thickness ratio: It is preferable that the outer layer cover = 1: 6 to 6: 1.
[0034]
Further, the deformation amount of the ball when a load of 100 kg is applied is normally 2.3 to 4.5 mm, particularly preferably 2.5 to 4.0 mm.
[0035]
The multi-piece solid golf ball of the present invention is formed by forming a large number of dimples on the surface in the same manner as a normal golf ball, and the number of dimples is not particularly limited, but is usually 350 to 500, preferably May be 370 to 480, more preferably 390 to 450, and the dimples may be two or more types having different diameters and depths. The diameter is usually adjusted to 1.4 to 4.5 mm, particularly 2.0 to 4.3 mm, and the depth is preferably 0.15 to 0.25 mm, particularly 0.17 to 0.23 mm. .
[0036]
The golf ball of the present invention can be appropriately set according to the golf rules as long as it does not deviate from the above range, and can be formed to have a weight of 45.93 g or less and a diameter of 42.67 mm or more.
[0037]
【The invention's effect】
The multi-piece solid golf ball of the present invention is excellent in durability against repeated hits, has an excellent spin performance with a large amount of spin on approach shots, and a small amount of spin on driver shots, and has excellent controllability, The flight distance can be increased and the scuff resistance is excellent.
[0038]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example.
[0039]
[Examples and comparative examples]
The composition shown in Table 1 is obtained by kneading the rubber composition of the composition shown in Table 1 (all units in parts by weight) with a kneader, placing it in a mold, and heat-pressing it at 150 ° C. for 15 minutes. Created a solid core.
[0040]
[Table 1]

[0041]
The obtained solid core is placed in a mold, and the inner layer cover materials shown in Tables 2 and 3 are injected to form the inner layer cover. Then, the inner layer cover is taken out and roughened by barrel polishing on the surface of the inner layer cover. Faced.
[0042]
The above roughened core is placed in a mold, and the outer layer cover materials shown in Tables 2 and 3 are injected. The total number of 432 pieces, the surface occupancy 70%, and the volume ratio (the phantom sphere volume of the ball without considering the dimple portion) The ratio of the total volume of the dimples to the weight) A multi-piece solid golf ball having 0.9% dimples was prepared.
[0043]
Comparative Example 1 is a two-piece solid golf ball in which the solid core shown in Table 1 is covered with one layer of the cover material shown in Table 3, and the number and manner of dimples are the same as described above.
[0044]
With respect to each manufactured solid golf ball, flying performance, spin performance, controllability, scratch resistance, and repeated impact durability were evaluated by the following methods. The results are also shown in Tables 2 and 3. In the table, the intermediate ball indicates a solid core formed with an inner layer cover.
[0045]
Flying performance Spin amount, initial speed, carry and total flying when using a swing robot made by True Temper with a head speed of 50m / sec (HS = 50) using a driver The distance was measured.
Spin performance Using a swinging robot similar to the above, the amount of spin when shot at a head speed of 20 m / sec (HS = 20) was measured using a pitching wedge.
Controllability 10 senior amateur players (so-called single players) made a sensory evaluation of the controllability when an approach shot was performed using a pitching wedge based on the following criteria.
○: Excellent △: Good ×: Bad
Scratch resistance Using a swinging robot similar to flying performance, using a pitching wedge, with a head speed of 30 m / sec (HS = 30), hitting the same ball three times repeatedly, visually inspecting the surface state of the ball And scored in 10 stages (indicating that the higher the score, the better).
Repeated hitting durability Using a swing robot similar to flying performance, using a screwdriver, hitting the same ball 300 times at a head speed of 45 m / sec (HS = 45), and then visually checking the state of the ball And comparative evaluation was performed on the state of each ball when Comparative Example 1 was taken as the reference value 100.
[0046]
[Table 2]

[0047]
[Table 3]

1) Product made by DuPont, acid content 18%, zinc ionomer (D65)
2) DuPont, acid content 18%, sodium ionomer (D66)
3) DuPont, acid content 20%, zinc ionomer (D67)
4) DuPont, acid content 20%, sodium ionomer (D68)
5) 15% acid content, Mitsui DuPont Polychemicals, zinc ionomer (D62)
6) Mitsui-DuPont Polychemicals, acid content 15%, sodium ionomer (D63)
7) Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate copolymer,
GMA content 6% by weight
8) Mitsui-DuPont Polychemical Co., Ltd., Ethylene-ethyl acrylate maleic anhydride graft modified 9) Exxon, ethylene-methacrylate-acrylic acid terpolymer 10) Toray DuPont, polyester elastomer ( D40)
11) Polyamide elastomer (D40) manufactured by Atchem
12) Dainippon Ink & Chemicals, polyurethane elastomer (D40)
* (D) indicates Shore D hardness.
13) Amount of deformation of the ball under a load of 100 kg 14) Initial velocity measured based on a measurement method of a golf ball official agency (USGA)
In the multi-piece solid golf ball of the present invention, the polymer obtained by graft copolymerization or random copolymerization of olefin compound with glycidyl methacrylate or organic acid is blended in the outer layer cover material, so that the inner layer and the outer layer cover are firmly bonded. It has a high spin rate on approach shots, a low spin rate on driver shots, excellent controllability and an excellent spin rate that can increase the flight distance, and scratches on iron shots can occur. It was found to be difficult and excellent in repeated hitting durability.
[0049]
On the other hand, the two-piece solid golf ball of Comparative Example 1 has too little spin performance at the time of driver and iron shot, poor controllability, and poor durability, and any cover material of Comparative Examples 2 to 4 In addition, the three-piece solid golf ball not blended with the above copolymer was extremely inferior in durability and scratch resistance.

Claims (3)

A multi-piece solid golf ball in which a solid core and a two-layered cover composed of an inner layer and an outer layer are coated on the solid core, wherein the inner layer cover contains at least 15% by weight of an α, β-unsaturated carboxylic acid ionomer resin The outer layer cover is one or more selected from polyurethane elastomer, polyester elastomer and polyamide elastomer, and does not contain an ionomer resin. A multi-piece solid golf ball comprising a polymer obtained by graft copolymerization or random copolymerization of glycidyl methacrylate or an organic acid with an olefin compound . The multi-piece solid golf ball according to claim 1 , wherein the hardness of the inner layer cover is Shore D hardness 60 to 75 and the outer layer cover is Shore D hardness 35 to 55 . A polymer obtained by graft copolymerization or random copolymerization of glycidyl methacrylate or an organic acid with the above olefin compound is an ethylene-glycidyl methacrylate copolymer, an ethylene-ethyl acrylate maleic anhydride graft-modified product, or an ethylene-methacrylate- The multi-piece solid golf ball of claim 1, which is an acrylic acid terpolymer.