JP3754509B2 - Hollow solid golf ball - Google Patents

Description

【００２３】
【表２】

【００２４】
実施例１〜５および比較例１〜２
上記のように得られた中空コア上に、表３に示す配合のカバー用組成物を被覆してカバー層を形成し、ペイント塗装を施して、直径42.7mmの中空ソリッドゴルフボールを作製した。
【表３】

【００２５】
比較例３
表２に示す配合のゴム組成物を用いて、165℃×20分プレス加硫することにより、直径38.5mmの中実のコアを得た。実施例１〜５および比較例１〜２と同様にしてカバー層を形成し、ペイント塗装を施して、直径42.7mmの中実ソリッドゴルフボールを作製した。
【００２６】
得られた各ゴルフボールについて、慣性モーメント、衝撃力、飛距離（キャリー）、打出角、打出スピン量、耐久性について評価を行い、その結果を表４に示す。試験方法は以下の通り行った。
（試験方法）
▲１▼慣性モーメント
INERTIA DYNAMICS社製の、モデルNo.005-002シリーズNo.M99274を用いて測定した。
▲２▼衝撃力
ツルーテンパー社製スイングロボットにドライバーを取付け、ゴルフボールをヘッドスピード45m/秒で打撃する際に、クラブヘッド後部に加速度計を取り付けてヘッドの進行方向に対して逆方向に生ずる加速度を測定し、この加速度の最大値を力に変換することによって求めた。
▲３▼飛距離
ツルーテンパー社製スイングロボットにドライバーを取付け、ゴルフボールをヘッドスピード45m/秒で打撃し、落下点までの距離(キャリー)を飛距離として測定した。
▲４▼打出角および打出スピン量
ゴルフボールとクラブヘッドのインパクトの瞬間を一定間隔に設置した２台のカメラによって、一定時間ずらして撮影して、その差から算出した。
▲５▼耐久性
ツルーテンパー社製スイングロボットにドライバーを取付け、ゴルフボールをヘッドスピード45m/秒で50回打撃した時の割れの有無を観察した。
〇 … 50回で割れなし
× … 50回以内に割れ発生
▲６▼打撃時のフィーリング
プロゴルファー10人によりドライバーで実打して評価する。評価基準は下記の通りである。
評価基準
◎ …８人以上が良いと回答
○ …５〜７人が良いと回答
△ …２〜４人が良いと回答
× …１人以下が良いと回答
【００２７】
（試験結果）
【表４】

【００２８】
以上の結果より、本発明のコア内部が中空で、かつ中空部の直径に適したコア組成を用いたソリッドゴルフボール（実施例１〜５）は、中空であるために衝撃力が小さくなり、軟らかい良好な打撃時フィーリングが得られ、かつ中実ボール（比較例３）に比べて慣性モーメントが大きくなり、バックスピン量が小さくなり、更に打出角が大きくなることにより、ドライバーでの飛距離も優れていることが認められた。
【００２９】
【発明の効果】
本発明のソリッドゴルフボールは、直径５〜30mmを有する中空部と中空コア外層部から成る中空コアを用いると共に、コア配合を中空コア専用配合とすることにより、反撥性能を損なうことなく、打撃時のフィーリングを良好なものとし、慣性モーメントを大きくし、打撃時の打出角を大きくし、飛距離を増大させたものである。
【図面の簡単な説明】
【図１】 本発明のゴルフボールの断面概略図である。
【符号の説明】
１ … 中空部
２ … 中空コア外層部
３ … カバー層
４ … 中空コア[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hollow solid golf ball comprising a hollow core and a cover layer. More specifically, the present invention has a good feeling at the time of hitting, a large moment of inertia, and a large launch angle at the time of hitting without impairing the resilience performance. The present invention relates to a golf ball having increased flight distance.
[0002]
[Prior art]
In the prior art, there are mainly two types of golf balls. One is a solid golf ball such as a solid two-piece ball, and is composed of a core made of an integrally molded rubber member and a thermoplastic resin cover such as an ionomer resin coated on the core. The other is a thread-wound golf ball, in which a central solid or liquid core is wound with a rubber thread winding, and then covered with a cover of ionomer resin or balata having a thickness of 1 to 2 mm. Two-piece solid golf balls have greater durability and higher flight characteristics than ball-wound golf balls because of their durability and higher ball speed at the time of hitting, and are used by many golfers, especially amateur golfers. . On the other hand, the two-piece solid golf ball has a problem that the feeling at the time of hitting is hard, and it is sometimes avoided by specific users such as women and seniors.
[0003]
In order to improve the feeling at the time of hitting, a method of softening the cover or softening the core has been used, but there is a disadvantage that the entire ball has insufficient rigidity and rebound becomes worse and the flight distance is reduced. did.
[0004]
[Problems to be solved by the invention]
The present invention solves the problems of the conventional two-piece solid golf ball as described above, maintains the excellent flight performance characteristic of the two-piece solid golf ball without impairing the resilience performance, and provides a fee for hitting. An object of the present invention is to provide a hollow solid golf ball having an improved ring.
[0005]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors used a hollow core (4) comprising a hollow portion (1) having a diameter of 5 to 30 mm and a hollow core outer layer portion (2), By limiting the core composition to a specific range in order to control the elastic modulus, the feeling at impact is improved without impairing the rebound performance, the moment of inertia is increased, and therefore the launch angle is large and immediately after launch. The present inventors have found that the flight distance can be increased by increasing the spin retention rate from when the ball is raised to when it is lowered, and the present invention has been completed.
[0006]
The spin retention of the ball is affected by the dimple shape, but is also affected by the moment of inertia of the ball. In general, the larger the moment of inertia, the smaller the spin amount at the time of launch on driver shots, and the ball does not blow up and the flight distance increases. More specifically, when a golf ball is hit with a golf club, spin occurs in the ball, and this spin causes lift in the normal direction with respect to the flight curve of the ball. In the component force, since a negative force acts on the ball with respect to the moving direction of the ball, the large ball speed immediately after the hit is reduced by the lift force. On the other hand, when the ball descends after passing the highest point of the flight curve, the lift due to the spin acts as a positive force with respect to the traveling direction in the horizontal component force. A large value is preferable for increasing the flight distance. Therefore, in order to increase the ball flight distance, it is preferable that the spin amount when the ball is raised immediately after launching is small and the spin amount when the ball is lowered is large (high spin retention). For this purpose, it is more preferable that the moment of inertia of the ball is large. Also, during an approach shot, the higher the moment of inertia, the easier the backspin is held and the better it stops.
[0007]
That is, the present invention comprises a hollow core (4) and a cover layer (3) formed on the core, wherein the hollow core (4) has a diameter of 5 to 30 mm and other than the hollow portion. In the hollow solid golf ball comprising the hollow core outer layer portion (2), the metal salt of unsaturated carboxylic acid with respect to 100 parts by weight of the polybutadiene rubber in which the hollow core outer layer portion has at least 90% or more of cis-1,4 bonds 30-60 parts by weight, an organic peroxide 0.1 to 2.0 parts by weight, containing a low specific gravity of zinc oxide 5 to 110 by weight of a filler, and a highly dense metal filler 5 to 110 by weight parts The present invention relates to a hollow solid golf ball comprising a rubber composition, wherein the cover is formed of an ionomer resin.
[0008]
Hereinafter, the present invention will be described in more detail. The golf ball of the present invention includes a hollow core (4) comprising a hollow portion (1) and a hollow core outer layer portion (2), and a cover layer (3) formed on the core. Consists of. The larger the diameter of the hollow portion of the hollow core (4), the larger the moment of inertia can be obtained.However, since the vulcanized molded layer of the rubber composition having rebound resilience in the core decreases, The diameter of the part is preferably in the range of 5 to 30 mm. If it is larger than 30 mm, it is necessary to use a large amount of filler for adjusting the specific gravity in the outer layer of the hollow core, and the rebound becomes too low. If it is smaller than 5 mm, the hollow effect cannot be seen. The diameter of the hollow core is 36 to 41 mm, whereby the thickness of the hollow core outer layer portion is 3 to 17 mm.
[0009]
The hollow core outer layer portion is obtained by heating, pressing and molding a rubber composition containing a base rubber, a metal salt of an unsaturated carboxylic acid, an organic peroxide, a filler and the like. As the base rubber, natural rubber and / or synthetic rubber conventionally used for solid golf balls is used, and in particular, so-called high cis having a cis-1,4-structure of at least 90% or more, preferably 95% or more. Polybutadiene rubber is preferable, and if desired, natural rubber, polyisoprene rubber, styrene polybutadiene rubber, EPDM, or the like may be blended.
[0010]
The metal salt of the unsaturated carboxylic acid acts as a co-crosslinking agent, and is particularly monovalent or zinc or magnesium salt of an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms such as acrylic acid or methacrylic acid. Although a divalent metal salt is mentioned, the zinc acrylate which provides high repellent property is suitable. The compounding amount is 30 to 60 parts by weight, preferably 30 to 50 parts by weight with respect to 100 parts by weight of the base rubber. If it exceeds 60 parts by weight, it becomes too hard and the feeling becomes poor, and if it is less than 30 parts by weight, the rebound becomes worse and the flight distance decreases. This blending amount may be adjusted to give a desired elastic modulus depending on the size of the hollow diameter, the type of cover material, and the like.
[0011]
Organic peroxides act as crosslinkers or curing agents such as dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,5-trimethylcyclohexane, 2,5-dimethyl-2,5- Examples thereof include di (t-butylperoxy) hexane and di-t-butyl peroxide, and dicumyl peroxide is preferable. The amount is 0.1 to 3.0 parts by weight, preferably 0.3 to 2.5 parts by weight, based on 100 parts by weight of the base rubber. If it is less than 0.1 parts by weight, it becomes too soft and the rebound becomes worse and the flight distance decreases. If it exceeds 2.0 parts by weight, it becomes too hard and the feeling becomes worse.
[0012]
The low specific gravity filler is not particularly limited as long as it is usually blended in the core of the golf ball, and examples thereof include inorganic salts such as zinc oxide, barium sulfate, calcium carbonate, etc. Is used. The high specific gravity metal filler has a specific gravity of 8 to 20, for example, metal powder, metal oxide, metal nitride, etc. or a mixture thereof, specifically tungsten (specific gravity 19.3), tungsten carbide (specific gravity 15.8), molybdenum (Specific gravity 10.2), lead (specific gravity 11.3), lead oxide (specific gravity 9.3), nickel (specific gravity 8.9) and copper (specific gravity 8.9) or a mixture thereof. Since the hollow core (4) used in the present invention tends to be deficient in weight compared to a normal solid core, it is preferable to use a mixture of a low specific gravity filler and a high specific gravity metal powder. The blending amount is preferably 5 to 110 parts by weight per 100 parts by weight of the base rubber. If it is less than 5 parts by weight, it is difficult to adjust the weight, and if it exceeds 110 parts by weight, the weight ratio of the rubber becomes small and the rebound becomes too low.
[0013]
As a method for producing a hollow solid golf ball of the present invention, first, two hemispheres made of a rubber composition are bonded together, or a hollow sphere having a thickness of 1 to 5 mm and a diameter of 6 to 20 mm is obtained by blow-injecting a thermosetting resin. Make it. The hollow spheres may be produced by preparing a generally known liquid center and then extracting the liquid inside with a syringe. At that time, the injection hole is sealed with a rubber sheet coated with an adhesive. Subsequently, hemispheres having a thickness of 3 to 17 mm and a diameter of 36 to 41 mm are produced from the rubber composition before vulcanization. If this thickness is less than 3 mm, the durability is deteriorated, and if it exceeds 17 mm, the diameter of the hollow portion becomes 5 mm or less, and the moment of inertia becomes small, and the effect is lost. The hollow sphere is inserted into the center of the two hemispheres, placed in a spherical mold, and vulcanized at a temperature of 150 to 170 ° C. to obtain a hollow core. This hemisphere can be obtained by inserting the rubber composition into a hemispherical mold previously maintained at 110 to 130 ° C. and compressing it with a hemispherical metal core. Although the cover resin is not limited thereto, the core is coated by injection molding and then painted to obtain a golf ball.
[0014]
The weight of the hollow core obtained by vulcanization is 30 to 40 g, preferably 32 to 39 g. Further, the specific gravity of the outer layer portion of the hollow core must be slightly higher than the specific gravity of the core of the conventional golf ball. Because there is a hollow portion, the specific gravity increases to compensate for the weight of the portion. Since the specific gravity of the conventional golf ball is 1.0 to 1.17, the specific gravity of the hollow core of the present application is 1.1 to 2.0, preferably 1.1 to 1.7.
[0015]
Next, a cover layer is coated on the hollow core. The cover can be formed of an ionomer resin that is usually used as a cover material for solid golf balls, and a small amount of other resin may be added.
[0016]
In addition, the cover composition contains an additive such as titanium dioxide for coloring, and other additives such as an ultraviolet absorber, a light stabilizer, a fluorescent material, or a fluorescent brightening agent, depending on the golf ball cover. Although it may contain in the range which does not impair a desired characteristic, normally the compounding quantity of a coloring agent has a preferable 0.1-0.5 weight part.
[0017]
The cover layer of the present invention is formed by a generally known method used for forming a golf ball cover, such as injection molding or press molding. The cover layer preferably has a thickness of 1 to 5 mm. When the cover layer is covered, a number of depressions called dimples are usually formed on the surface. The golf ball of the present invention is usually coated with paint and put on the market in order to enhance the beauty and increase the commercial value.
[0018]
The present invention provides a golf ball having a good feeling at impact, a large moment of inertia, a large launch angle at impact, and an increased flight distance without impairing rebound performance.
[0019]
【Example】
The present invention will be described in further detail with reference to examples. However, the present invention is not limited to these examples.
[0020]
Production of hollow rubber spheres A rubber composition having the composition shown in Table 1 below was vulcanized and molded at 155 ° C for 15 minutes to produce hollow rubber hemispheres having a rubber thickness of 2 mm. As shown in Table 2, the diameter of the hollow part was four types. Using an acetone solution of the rubber composition shown in Table 1, two of these hollow rubber hemispheres were pre-bonded and vulcanized and bonded at 155 ° C. for 20 minutes to prepare hollow rubber balls. The hollow rubber spheres may be produced by producing a generally known liquid center and then extracting the liquid therein with a syringe. At that time, the injection hole is sealed with a rubber sheet coated with an adhesive.
[0021]
Production of hollow core A rubber composition having the composition shown in Table 2 was put on both sides of a half-pressing mold for core press, and a hemispherical convex core mold having a hollow center diameter was sandwiched between the molds, and 165C x 2 After preliminarily molding, the core mold was removed, the hollow center was enclosed therein, and press vulcanized at 165 ° C. for 20 minutes to obtain a hollow core having a diameter of 38.5 mm.
[0022]
[Table 1]

[0023]
[Table 2]

[0024]
Examples 1-5 and Comparative Examples 1-2
A cover layer having the composition shown in Table 3 was coated on the hollow core obtained as described above to form a cover layer, and paint coating was performed to produce a hollow solid golf ball having a diameter of 42.7 mm.
[Table 3]

[0025]
Comparative Example 3
A solid core having a diameter of 38.5 mm was obtained by press vulcanization at 165 ° C. for 20 minutes using the rubber composition having the composition shown in Table 2. A cover layer was formed in the same manner as in Examples 1 to 5 and Comparative Examples 1 and 2, and paint coating was performed to produce a solid solid golf ball having a diameter of 42.7 mm.
[0026]
Each golf ball obtained was evaluated for moment of inertia, impact force, flight distance (carry), launch angle, launch spin amount, and durability. Table 4 shows the results. The test method was as follows.
(Test method)
(1) Moment of inertia
Measurement was performed using Model No. 005-002 series No. M99274 manufactured by INERTIA DYNAMICS.
(2) Impact force When a driver is attached to a swing robot manufactured by True Temper and a golf ball is hit at a head speed of 45 m / sec, an accelerometer is attached to the rear of the club head, resulting in a direction opposite to the head traveling direction. The acceleration was measured and obtained by converting the maximum value of the acceleration into a force.
(3) Flying distance A driver was attached to a swing robot manufactured by True Temper, a golf ball was hit at a head speed of 45 m / sec, and the distance to the falling point (carry) was measured as the flying distance.
(4) Launch angle and launch spin amount The moments of impact between the golf ball and the club head were taken with two cameras set at regular intervals, and the difference was calculated from the difference.
(5) Durability A driver was attached to a swing robot manufactured by True Temper, and the presence or absence of cracks was observed when the golf ball was hit 50 times at a head speed of 45 m / sec.
〇… No cracking after 50 times ×… Cracking within 50 times (6) Feeling at the time of hitting Evaluation by hitting with 10 drivers professional golfers. The evaluation criteria are as follows.
Evaluation criteria ◎… Reply that 8 or more are good ○… Respond that 5 to 7 is good △… Respond that 2 to 4 are good ×… Respond that 1 or less is good [0027]
(Test results)
[Table 4]

[0028]
From the above results, the solid golf ball (Examples 1 to 5) using the core composition suitable for the diameter of the hollow portion having a hollow inside the core of the present invention has a small impact force because it is hollow, A soft and good feeling at impact is obtained, and the moment of inertia is larger than that of a solid ball (Comparative Example 3), the backspin amount is reduced, and the launch angle is further increased. Was also found to be excellent.
[0029]
【The invention's effect】
The solid golf ball of the present invention uses a hollow core composed of a hollow portion having a diameter of 5 to 30 mm and a hollow core outer layer portion, and by making the core compounded exclusively for the hollow core, it does not impair the repulsion performance, and at the time of hitting The feeling of this is good, the moment of inertia is increased, the launch angle at the time of impact is increased, and the flight distance is increased.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a golf ball of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Hollow part 2 ... Hollow core outer-layer part 3 ... Cover layer 4 ... Hollow core

Claims (3)

It consists of a hollow core (4) and a cover layer (3) formed on the core, the hollow core (4) having a diameter of 5 to 30 mm, and a hollow core outer layer portion other than the hollow portion ( 2) In the hollow solid golf ball comprising 2), 30 to 60 parts by weight of a metal salt of unsaturated carboxylic acid with respect to 100 parts by weight of polybutadiene rubber in which the hollow core outer layer part has at least 90% or more of cis-1,4 bonds, organic peroxide 0.1 to 2.0 parts by weight, it consists of a rubber composition containing the low specific gravity of zinc oxide 5 to 110 by weight of a filler, and a highly dense metal filler 5 to 110 by weight portion, A hollow solid golf ball, wherein the cover is formed of an ionomer resin.   The hollow solid golf ball of claim 1, wherein the high specific gravity metal filler has a specific gravity of 8 to 20 and is selected from the group consisting of metal powder, metal oxide, metal nitride, and mixtures thereof.   The hollow solid golf ball according to claim 1, wherein the high specific gravity metal filler is tungsten.

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