JP2013183833A - Golf ball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf ball 2 which can be easily evaluated objectively.SOLUTION: A golf ball 2 includes a spherical core 4 and a cover 6 located outside the core 4. The core 4 includes a spherical center 8 and an intermediate layer 10 located outside the center 8. The cover 6 is formed of a first hemisphere 6a and a second hemisphere 6b. The first hemisphere 6a is made of a first resin composition. The second hemisphere 6b is made of a second resin composition. The specifications of the first hemisphere 6a are different from those of the second hemisphere 6b. As the specifications, hardness, composition, thickness and dimple patterns are illustrated. The base material polymer of the first resin composition may be different from that of the second resin composition. The contents of ultraviolet absorbent in the first resin composition may be different from those in the second resin composition. The contents of light stabilizer in the first resin composition may be different from those in the second resin composition.

Description

  The present invention relates to a golf ball. Specifically, the present invention relates to an improvement in a golf ball cover or paint layer.

  A typical golf ball, excluding a practice golf ball, includes a core, a cover, and a paint layer. The core is formed by crosslinking a rubber composition. There are cores with two or more layers. There is also a golf ball in which a part of the core is made of a resin composition. The cover is formed from a resin composition. There are covers with two or more layers. The cover has a dimple pattern on its surface.

  For forming the cover, a compression molding method, an injection molding method, or the like is employed. In the compression molding method, a half shell made of a resin composition is prepared. Two half shells cover the core. Both the core and the half shell are put into a mold including an upper mold and a lower mold having a hemispherical cavity. In this mold, the half shell is pressurized and heated. The half-shell resin composition melts and flows in the mold. This resin composition is solidified to form a cover. A paint (paint composition) is applied on the cover. The paint is cured to form a paint layer.

  Japanese Patent Application Laid-Open No. 63-38476 discloses a compression molding method for golf balls. In this compression molding method, the core is covered with two half shells having different colors.

  Golf ball manufacturers are conducting various tests on golf balls. For example, mechanical properties, feel at impact, durability, weather resistance, stain resistance, scratch resistance, and the like have been evaluated.

JP 63-38476 A

  In the evaluation of golf balls, a plurality of types of golf balls having different specifications are prepared. This preparation takes time. Furthermore, in order to obtain an objective evaluation result, the test conditions for the golf ball having the first specification and the test conditions for the golf ball having the second specification need to match. This matching is not easy.

  An object of the present invention is to provide a golf ball that can be easily objectively evaluated.

  The golf ball according to the present invention includes a core and a cover. This cover consists of a first hemisphere and a second hemisphere. The specification of the first hemisphere is different from the specification of the second hemisphere.

  The first hemisphere is made of the first resin composition. The second hemisphere is made of the second resin composition. Preferably, the composition of the first resin composition is different from the composition of the second resin composition. Preferably, the base resin of the first resin composition is different from the base resin of the second resin composition. Preferably, the hardness of the first resin composition is different from the hardness of the second resin composition.

  The first hemisphere may be composed of a first resin composition based on polyurethane, and the second hemisphere may be composed of a second resin composition based on another polyurethane. Preferably, the molecular weight of the polyol component of the polyurethane of the first resin composition is different from the molecular weight of the polyol component of the polyurethane of the second resin composition.

  The main component of the base resin of the first resin composition may be polyurethane, and the main component of the base resin of the second resin composition may be an ionomer resin.

  The first resin composition may contain an additive, and the second resin composition may contain another additive. The first resin composition may contain an ultraviolet absorber, and the second resin composition may contain another ultraviolet absorber. The first resin composition may contain a light stabilizer, and the second resin composition may contain another light stabilizer. The first resin composition may contain a specific gravity adjusting agent, and the second resin composition may contain another specific gravity adjusting agent.

  Preferably, the amount of additive in the first resin composition is different from the amount of additive in the second resin composition. Examples of the additive include an ultraviolet absorber, a light stabilizer, and a specific gravity adjuster.

  Preferably, the number of layers in the first hemisphere is different from the number of layers in the second hemisphere. Preferably, the dimple pattern of the first hemisphere is different from the dimple pattern of the second hemisphere.

  According to another aspect of the present invention, a golf ball according to the present invention includes a core, a cover, and a paint layer. This paint layer consists of a first hemisphere and a second hemisphere. The specification of the first hemisphere is different from the specification of the second hemisphere.

  The first hemisphere may be made of the first resin composition, and the second hemisphere may be made of the second resin composition. Preferably, the composition of the first resin composition is different from the composition of the second resin composition.

  The first resin composition may contain a glitter pigment, and the second resin composition may contain another glitter pigment.

  Preferably, the content of the glitter pigment in the first resin composition is different from the content of the glitter pigment in the second resin composition.

  Preferably, the hardness of the first hemisphere is different from the hardness of the second hemisphere. Preferably, the thickness of the first hemisphere is different from the thickness of the second hemisphere.

According to still another aspect of the present invention, a golf ball cover evaluation method according to the present invention includes:
A process for producing a golf ball comprising a core and a cover, the cover comprising a first hemisphere and a second hemisphere, wherein the specifications of the first hemisphere are different from the specifications of the second hemisphere;
A step of testing the golf ball;
And comparing the performance of the specification of the first hemisphere with the performance of the specification of the second hemisphere.

According to still another aspect of the present invention, a golf ball paint layer evaluation method according to the present invention includes a core, a cover, and a paint layer, and the paint layer includes a first hemisphere and a second hemisphere. A process for producing a golf ball in which the specifications of the first hemisphere are different from those of the second hemisphere,
A step of testing the golf ball;
And comparing the performance of the specification of the first hemisphere with the performance of the specification of the second hemisphere.

  In the golf ball according to the present invention, the performance of the first specification and the performance of the second specification can be compared by a test on one golf ball. This golf ball can contribute to the objectivity and efficiency of evaluation.

FIG. 1 is a cross-sectional view illustrating a golf ball according to an embodiment of the present invention. FIG. 2 is an exploded view showing a core and a half shell for the golf ball of FIG. FIG. 3 is a cross-sectional view illustrating a golf ball according to another embodiment of the present invention.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

  A golf ball 2 shown in FIG. 1 includes a spherical core 4 and a cover 6 positioned outside the core 4. The core 4 includes a spherical center 8 and an intermediate layer 10 located outside the center 8. The cover 6 includes a first hemisphere 6a and a second hemisphere 6b. The first hemisphere 6 a is combined with the second hemisphere 6 b on the equator of the golf ball 2. The cover 6 has a large number of dimples 12 on the surface thereof. A portion of the surface of the cover 6 other than the dimples 12 is a land 14. The golf ball 2 includes a paint layer and a mark layer outside the cover 6, but these layers are not shown.

  The center 8 is formed by crosslinking the rubber composition. Examples of the base rubber of the rubber composition include polybutadiene, polyisoprene, styrene-butadiene copolymer, ethylene-propylene-diene copolymer, and natural rubber. Two or more kinds of rubbers may be used in combination. From the viewpoint of resilience performance, polybutadiene is preferred, and high cis polybutadiene is particularly preferred.

  For crosslinking of the center 8, a co-crosslinking agent is preferably used. From the viewpoint of resilience performance, preferred co-crosslinking agents are zinc acrylate, magnesium acrylate, zinc methacrylate and magnesium methacrylate. It is preferable that the rubber composition contains an organic peroxide together with a co-crosslinking agent. Preferred organic peroxides include dicumyl peroxide, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (t-butyl). Peroxy) hexane and di-t-butyl peroxide.

  In the rubber composition of the center 8, various additives such as a filler, sulfur, a vulcanization accelerator, a sulfur compound, an anti-aging agent, a colorant, a plasticizer, and a dispersant are blended in appropriate amounts as necessary. Synthetic resin powder or crosslinked rubber powder may be blended with the rubber composition.

  The center 8 has a diameter of preferably 30.0 mm or more, particularly preferably 38.0 mm or more. The diameter of the center 8 is preferably 42.0 mm or less, and particularly preferably 41.5 mm or less. The center 8 may be composed of two or more layers. The center 8 may include a rib on the surface thereof. The center 8 may be hollow.

  A suitable polymer for the mid layer 10 is an ionomer resin. A preferable ionomer resin includes a binary copolymer of an α-olefin and an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms. As another preferable ionomer resin, a ternary copolymer of an α-olefin, an α, β-unsaturated carboxylic acid having 3 to 8 carbon atoms and an α, β-unsaturated carboxylic acid ester having 2 to 22 carbon atoms is used. A polymer is mentioned. In this binary copolymer and ternary copolymer, preferred α-olefins are ethylene and propylene, and preferred α, β-unsaturated carboxylic acids are acrylic acid and methacrylic acid. In this binary copolymer and ternary copolymer, some of the carboxyl groups are neutralized with metal ions. Examples of the metal ions for neutralization include sodium ions, potassium ions, lithium ions, zinc ions, calcium ions, magnesium ions, aluminum ions, and neodymium ions.

  Other polymers may be used for the mid layer 10 instead of the ionomer resin. Examples of other polymers include polystyrene, polyamide, polyester, polyolefin, and polyurethane. Two or more kinds of polymers may be used in combination.

  For the intermediate layer 10, a colorant such as titanium dioxide, a specific gravity adjusting agent such as barium sulfate, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent agent, a fluorescent brightening agent, etc. Is blended in an appropriate amount. For the purpose of adjusting the specific gravity, the intermediate layer 10 may be mixed with a powder of a high specific gravity metal such as tungsten or molybdenum.

  The thickness of the mid layer 10 is preferably 0.2 mm or more, and particularly preferably 0.3 mm or more. The thickness of the mid layer 10 is preferably 2.5 mm or less, and particularly preferably 2.2 mm or less. The specific gravity of the mid layer 10 is preferably 0.90 or more, particularly preferably 0.95 or more. The specific gravity of the intermediate layer 10 is preferably 1.10 or less, particularly preferably 1.05 or less. The intermediate layer 10 may be composed of two or more layers. The mid layer 10 may be formed by crosslinking the rubber composition. The golf ball 2 may include a core that does not have the mid layer 10.

  The cover 6 is made of a resin composition. Examples of the base polymer of the resin composition include polyurethane, ionomer resin, polystyrene, polyamide, polyester, and polyolefin. Two or more kinds of polymers may be used in combination.

  The resin composition of the cover 6 can contain an additive. Specific examples of the additive include a colorant such as titanium dioxide, a specific gravity adjusting agent such as barium sulfate, a dispersant, an antioxidant, an ultraviolet absorber, a light stabilizer, a fluorescent agent, and a fluorescent brightening agent. .

  The thickness of the cover 6 is preferably 0.2 mm or more, and particularly preferably 0.3 mm or more. The thickness of the cover 6 is preferably 2.5 mm or less, and particularly preferably 2.2 mm or less. The specific gravity of the cover 6 is preferably 0.90 or more, particularly preferably 0.95 or more. The specific gravity of the cover 6 is preferably 1.10 or less, and particularly preferably 1.05 or less. The cover 6 may be composed of two or more layers.

  The golf ball 2 may include a reinforcing layer between the mid layer 10 and the cover 6. The reinforcing layer is firmly attached to the intermediate layer 10 and is also firmly attached to the cover 6. The reinforcing layer suppresses peeling of the cover 6 from the intermediate layer 10. Examples of the base polymer of the reinforcing layer include two-component curable epoxy resins and two-component curable urethane resins.

  As described above, the cover 6 includes the first hemisphere 6a and the second hemisphere 6b. The 1st hemisphere 6a consists of a 1st resin composition. The second hemisphere 6b is made of the second resin composition. The specification of the first hemisphere 6a is different from the specification of the second hemisphere 6b. The specifications include hardness, composition, thickness, and dimple pattern. The base resin of the first resin composition may be different from the base resin of the second resin composition. The kind of additive in the first resin composition may be different from the kind of additive in the second resin composition. The additive content in the first resin composition may be different from the additive content in the second resin composition. The kind of ultraviolet absorber in the first resin composition may be different from the kind of ultraviolet absorber in the second resin composition. The content of the ultraviolet absorbent in the first resin composition may be different from the content of the ultraviolet absorbent in the second resin composition. The kind of light stabilizer in the first resin composition may be different from the kind of light stabilizer in the second resin composition. The content of the light stabilizer in the first resin composition may be different from the content of the light stabilizer in the second resin composition. The kind of specific gravity regulator in the first resin composition may be different from the kind of specific gravity regulator in the second resin composition. The content of the specific gravity adjusting agent in the first resin composition may be different from the content of the specific gravity adjusting agent in the second resin composition.

  When this golf ball 2 is subjected to the test, the performance of the first hemisphere 6a and the performance of the second hemisphere 6b are found. The performance of the first hemisphere 6a can be contrasted with the performance of the second hemisphere 6b.

  When the golf ball 2 is manufactured, as shown in FIG. 2, a first half shell 16a and a second half shell 16b are prepared. The first half shell 16a is made of a first resin composition. The second half shell 16b is made of the second resin composition. The core 4 is covered with the first half shell 16a and the second half shell 16b. The core 4 and the half shells 16a and 16b are put into a mold composed of an upper mold and a lower mold each having a hemispherical cavity. In this mold, the half shells 16a and 16b are pressurized and heated. The resin compositions of the half shells 16a and 16b melt and flow in the mold. The resin composition is solidified to obtain the cover 6. Dimples 12 are formed by pimples formed on the cavity surface.

  FIG. 3 shows a golf ball 17 according to another embodiment of the present invention. The golf ball 17 includes a spherical core 18, a cover 20 positioned outside the core 18, and a paint layer 22 positioned outside the cover 20. The core 18 includes a spherical center 24 and an intermediate layer 26 located outside the center 24. The paint layer 22 includes a first hemisphere 22a and a second hemisphere 22b. The first hemisphere 22 a is combined with the second hemisphere 22 b on the equator of the golf ball 17.

  The paint layer 22 covers the cover 20. The cover 20 is protected by the paint layer 22. The paint layer 22 achieves an excellent appearance of the golf ball 17. The paint layer 22 is formed by applying a paint. For the application, an electrostatic coating method, a spray gun method, a brush coating method, a dipping method, or the like can be employed.

  The paint consists of a resin composition. Examples of the base resin for the paint include polyurethane, epoxy resin, polyester, acrylic resin, and cellulose resin. From the viewpoint of durability of the paint layer 22, a two-component curable polyurethane is preferable.

  A two-component curable polyurethane is obtained by a reaction between a main agent and a curing agent. A two-component curable polyurethane obtained by a reaction between a main component containing a polyol component and a curing agent containing a polyisocyanate (including a polyisocyanate derivative) is preferred.

  It is preferable that urethane polyol is used as the polyol component of the main agent. Urethane polyol has a urethane bond and two or more hydroxyl groups. Preferably, the urethane polyol has a hydroxyl group at its terminal. The urethane polyol can be obtained by reacting the polyol and the polyisocyanate at a ratio such that the hydroxyl group of the polyol component is excessive in molar ratio with respect to the isocyanate group of the polyisocyanate.

  The polyol used for the production of the urethane polyol has a plurality of hydroxyl groups. A polyol having a weight average molecular weight of 50 to 2000, particularly 100 to 1900 is preferred. Examples of the low molecular weight polyol include diol and triol. Specific examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol and 1,6-hexanediol. Specific examples of the triol include glycerin, trimethylolpropane, and hexanetriol. High molecular weight polyols include polyether polyols such as polyoxyethylene glycol (PEG), polyoxypropylene glycol (PPG) and polyoxytetramethylene glycol (PTMG); polyethylene adipate (PEA), polybutylene adipate (PBA) ) And polyhexamethylene adipate (PHMA); lactone polyester polyols such as poly-ε-caprolactone (PCL); polycarbonate polyols such as polyhexamethylene carbonate; and acrylic polyols. Two or more polyols may be used in combination.

The polyisocyanate used for the production of the urethane polyol has a plurality of isocyanate groups. Specific examples of the polyisocyanate include 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, a mixture of 2,4-toluene diisocyanate and 2,6-toluene diisocyanate (TDI), and 4,4′-diphenylmethane diisocyanate (MDI). ), 1,5-naphthylene diisocyanate (NDI), 3,3′-vitrylene-4,4′-diisocyanate (TODI), xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI) and paraphenylene diisocyanate ( Aromatic polyisocyanates such as PPDI); 4,4′-dicyclohexylmethane diisocyanate (H ₁₂ MDI), hydrogenated xylylene diisocyanate (H ₆ XDI) and isophorone diisocyanate (IPDI) ); And aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI). Two or more polyisocyanates may be used in combination. From the viewpoint of weather resistance, TMXDI, XDI, HDI, H ₆ XDI, IPDI and H ₁₂ MDI are preferred.

  The curing agent contains polyisocyanate or a derivative thereof. The aforementioned polyisocyanate, which is a raw material of urethane polyol, can be used as a curing agent.

  As described above, the paint layer 22 includes the first hemisphere 22a and the second hemisphere 22b. The first hemisphere 22a is made of the first paint composition. The second hemisphere 22b is made of the second paint composition. The specification of the first hemisphere 22a is different from the specification of the second hemisphere 22b. The specifications include composition, hardness and thickness. The base resin of the first paint composition may be different from the base resin of the second paint composition. The pigment type in the first paint composition may be different from the pigment type in the second paint composition. The pigment content in the first paint composition may be different from the pigment content in the second paint composition.

  When this golf ball 17 is subjected to the test, the performance of the first hemisphere 22a and the performance of the second hemisphere 22b are found. The performance of the first hemisphere 22a can be contrasted with the performance of the second hemisphere 22b.

  When the golf ball 17 is manufactured, the first paint composition is applied to the cover 20 with half of the cover 20 masked. A first hemisphere 22a is formed from this first paint composition. The masking is removed and another masking is applied on the first hemisphere 22a. Further, the second paint composition is applied to the cover 20. From this second paint composition, a second hemisphere 22b is formed.

  Hereinafter, the effects of the present invention will be clarified by examples. However, the present invention should not be construed in a limited manner based on the description of the examples.

[Center]
100 parts by mass of high-cis polybutadiene (trade name “BR-730” from JSR), 5.15 parts by weight of Finco, 28.5 parts by weight of zinc acrylate (trade name “ZN-DA90S” by Nippon Distillation Co., Ltd.) ) 5 parts by weight of zinc oxide, 12.9 parts by weight of barium sulfate, 0.3 parts by weight of bis (pentabromophenyl) disulfide and 0.9 parts by weight of dicumyl peroxide (trade name of NOF Corporation “ Park mill D ") was kneaded to obtain a rubber composition. This rubber composition was put into a mold composed of an upper mold and a lower mold each having a hemispherical cavity and heated at 170 ° C. for 18 minutes to obtain a center having a diameter of 39.7 m.

[Middle layer]
50 parts by weight of ionomer resin (trade name “HIMILAN 1605” from Mitsui DuPont Polychemical), 50 parts by weight of another ionomer resin (trade name “HIMILAN AM7329” from Mitsui DuPont Polychemical) and 4 parts by weight of dioxide dioxide. Titanium was kneaded with a twin-screw kneading extruder to obtain a resin composition. This resin composition was coated around the center by an injection molding method to form an intermediate layer. The thickness of this intermediate layer was 1.0 mm.

[cover]
A first half shell was molded from the first resin composition by compression molding. A second half shell was molded from the second resin composition. These half shells covered the core. The half shell and the core were both put into a final mold including an upper mold and a lower mold having a hemispherical cavity and a large number of pimples on the cavity surface, and a cover was obtained by a compression molding method. The cover thickness was 0.5 mm. A first hemisphere of the cover was formed from the first half shell. A second hemisphere of the cover was formed from the second half shell. A dimple having a shape obtained by inverting the shape of the pimple was formed on the cover. Details of the resin compositions AH that can be used for the first hemisphere and the second hemisphere are shown in Table 1 below.

The details of the polyurethane in Table 1 are as follows.
Polyurethane # 1
BASF Japan Thermoplastic Polyurethane Elastomer Product Name: Elastollan NY82A10 Clear Polyoxytetramethylene glycol weight average molecular weight: 1400
Polyurethane # 2
BASF Japan Thermoplastic Polyurethane Elastomer Product Name: Elastollan NY88A10 Clear Polyoxytetramethylene glycol weight average molecular weight: 1400
Polyurethane # 3
BASF Japan Thermoplastic Polyurethane Elastomer Product Name: Elastollan XNY88A10 Clear Polyoxytetramethylene glycol weight average molecular weight: 1700

[Paint layer]
The first paint composition and the second paint composition were applied around the cover to obtain a paint layer. From the first paint composition, a first hemisphere of the paint layer was formed. A second hemisphere of the paint layer was formed from the second paint composition. Details of paint compositions (i) to (iv) that can be used in the first and second hemispheres are shown in Table 2 below.

  The main agent used in the paint layer of Table 2 is “Porin # 950”, a trade name of Shinto Paint Co., Ltd. The main agent is a urethane polyol composed of a polyol component (trimethylolpropane, polyoxytetramethylene glycol) and a polyisocyanate component (isophorone diisocyanate). The hydroxyl value of this main agent is 128 mgKOH / g.

The curing agent used for the paint layer of Table 2 is a mixture of the following compounds (a)-(c). The mass ratio (a / b / c) of these compounds is 30/30/40.
(A) Isocyanurate modified product of hexamethylene diisocyanate (trade name “Duranate TKA-100”, Asahi Kasei Chemicals Corporation), NCO content: 21.7%
(B) A modified burette of hexamethylene diisocyanate (trade name “Duranate 21S-75E” manufactured by Asahi Kasei Chemicals), NCO content: 15.5%
(C) Isocyanurate form of isophorone diisocyanate (Degussa's trade name “VESTANAT T1890”), NCO content: 12.0%

[Experiment 1]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition B. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit with a sand wedge alternately by the golf ball with the first hemispherical pole and the second hemispherical pole. Each strike was 20 times. When the golf ball after hitting was visually observed, it was found that the first hemisphere had better scratch resistance than the second hemisphere. In this experiment, the scratch resistance of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by variations in physical properties of the core.

[Experiment 2]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition B. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Seven out of ten golfers replied, “When you hit the first hemisphere, you feel softer.” In this experiment, the hit feeling of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by variations in physical properties of the core.

[Experiment 3]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition C. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit with a sand wedge alternately by the golf ball with the first hemispherical pole and the second hemispherical pole. Each strike was 20 times. When the golf ball after hitting was visually observed, it was found that the first hemisphere had better scratch resistance than the second hemisphere. In this experiment, the scratch resistance of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by variations in physical properties of the core.

[Experiment 4]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition C. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Nine out of 10 golfers replied, “When you hit the first hemisphere, you feel softer when you hit the ball.” In this experiment, the hit feeling of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by variations in physical properties of the core.

[Experiment 5]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition D. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). This golf ball was fixed to a sunshine weather meter, and this weather meter was operated for 60 hours. When the golf ball after the test was visually observed, it was found that the first hemisphere had better weather resistance than the second hemisphere. In this experiment, the weather resistance of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by the mounting position of the golf ball in the weather meter.

[Experiment 6]
The first hemisphere of the cover is molded with the resin composition A, and a half shell made of the resin composition B and having a thickness of 0.25 mm is stacked on the outside of the half shell made of the resin composition A and having a thickness of 0.25 mm. The second hemisphere was molded. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Six out of 10 golfers replied, “When you hit the first hemisphere, you feel softer.” In this experiment, the difference in feel at impact resulting from the difference in the number of half-shell layers can be evaluated with one type of golf ball. In this experiment, evaluation can be performed without being affected by variations in physical properties of the core.

[Experiment 7]
The first hemisphere of the cover is molded with the resin composition A, and the half shell made of the resin composition C and having a thickness of 0.25 mm is stacked on the outside of the half shell made of the resin composition B and having a thickness of 0.25 mm. The second hemisphere was molded. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. 10 golfers out of 10 replied, “When hitting the first hemisphere, the shot feel is softer.” In this experiment, the difference in feel at impact resulting from the difference in the number of half-shell layers can be evaluated with one type of golf ball. In this experiment, evaluation can be performed without being affected by variations in physical properties of the core.

[Experiment 8]
The first hemisphere of the cover was molded with the resin composition B, and the second hemisphere of the cover was molded with the resin composition E. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Eight out of 10 golfers replied, “When you hit the first hemisphere, you feel softer.” In this experiment, the hit feeling of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by variations in physical properties of the core.

[Experiment 9]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition F. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). This golf ball was fixed to a sunshine weather meter, and this weather meter was operated for 60 hours. When the golf ball after the test was visually observed, it was found that the first hemisphere had better weather resistance than the second hemisphere. In this experiment, the weather resistance of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by the mounting position of the golf ball in the weather meter.

[Experiment 10]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition G. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). This golf ball was fixed to a sunshine weather meter, and this weather meter was operated for 60 hours. When the golf ball after the test was visually observed, it was found that the first hemisphere had better weather resistance than the second hemisphere. In this experiment, the weather resistance of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by the mounting position of the golf ball in the weather meter.

[Experiment 11]
The first hemisphere of the cover was molded with the resin composition A, and the second hemisphere of the cover was molded with the resin composition H. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Six out of 10 golfers replied, “When you hit the first hemisphere, you feel softer.” In this experiment, the hit feeling of two types of resin compositions can be evaluated with one type of golf ball. In this experiment, two types of resin compositions can be evaluated without being affected by variations in physical properties of the core.

[Experiment 12]
The first hemisphere and the second hemisphere of the cover were molded with the resin composition A. The first hemisphere of the paint layer was formed with the paint composition (i), and the second hemisphere of the paint layer was formed with the paint composition (v) to obtain a golf ball. The golf ball was hit with a sand wedge alternately by the golf ball with the first hemispherical pole and the second hemispherical pole. Each strike was 20 times. When the golf ball after hitting was visually observed, it was found that the first hemisphere had better scratch resistance than the second hemisphere. In this experiment, the scratch resistance of two types of paint compositions can be evaluated with one type of golf ball. In this experiment, two types of paint compositions can be evaluated without being affected by variations in physical properties of the core and cover.

[Experiment 13]
The first hemisphere and the second hemisphere of the cover were molded with the resin composition A. The first hemisphere of the paint layer was formed with the paint composition (i), and the second hemisphere of the paint layer was formed with the paint composition (v) to obtain a golf ball. The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Six out of ten golfers replied, “When you hit the second hemisphere, you feel softer.” In this experiment, the hit feeling of two types of paint compositions can be evaluated with one type of golf ball. In this experiment, two types of paint compositions can be evaluated without being affected by variations in physical properties of the core and cover.

[Experiment 14]
The first hemisphere and the second hemisphere of the cover were molded with the resin composition A. A golf ball is formed by forming a first hemisphere of a paint layer having a thickness of 20 μm from the paint composition (i), and forming a second hemisphere of the paint layer having a thickness of 10 μm by the paint composition (ii). Obtained. The golf ball was hit with a sand wedge alternately by the golf ball with the first hemispherical pole and the second hemispherical pole. Each strike was 20 times. When the golf ball after hitting was visually observed, it was found that the first hemisphere had better scratch resistance than the second hemisphere. In this experiment, the scratch resistance of two types of paint compositions can be evaluated with one type of golf ball. In this experiment, two types of paint compositions can be evaluated without being affected by variations in physical properties of the core and cover.

[Experiment 15]
The first hemisphere and the second hemisphere of the cover were molded with the resin composition A. A golf ball is formed by forming a first hemisphere of a paint layer having a thickness of 20 μm from the paint composition (i), and forming a second hemisphere of the paint layer having a thickness of 10 μm by the paint composition (ii). Obtained. The golf ball was hit by 10 golfers with a putter on the first hemisphere pole and the second hemisphere pole. Six out of 10 golfers replied, “When you hit the first hemisphere, you feel softer.” In this experiment, the hit feeling of two types of paint compositions can be evaluated with one type of golf ball. In this experiment, two types of paint compositions can be evaluated without being affected by variations in physical properties of the core and cover.

[Experiment 16]
The first hemisphere and the second hemisphere of the cover were molded with the resin composition A. The first hemisphere of the paint layer was formed with the paint composition (i), and the second hemisphere of the paint layer was formed with the paint composition (iii) to obtain a golf ball. The appearance of this golf ball was visually observed by 10 golfers. 10 golfers out of 10 answered that the second hemisphere looks better. In this experiment, the appearance of two types of paint compositions can be evaluated with one type of golf ball.

[Experiment 17]
The first hemisphere and the second hemisphere of the cover were molded with the resin composition A. A first hemisphere of the paint layer was formed with the paint composition (iii), and a second hemisphere of the paint layer was formed with the paint composition (iv) to obtain a golf ball. The appearance of this golf ball was visually observed by 10 golfers. Seven out of ten golfers replied, “The second hemisphere looks better.” In this experiment, the appearance of two types of paint compositions can be evaluated with one type of golf ball.

[Experiment 18]
A first hemisphere and a second hemisphere of the cover were molded from the resin composition A using a mold having an upper mold dimple pattern different from the lower mold dimple pattern. A golf ball was obtained by forming a first hemisphere and a second hemisphere of the paint layer with the paint composition (i). The occupation ratio of the dimples in the first hemisphere obtained from the upper mold is 75%. The occupancy ratio of the dimples in the second hemisphere obtained from the lower mold is 83%. The golf ball was hit with a sand wedge alternately by the golf ball with the first hemispherical pole and the second hemispherical pole. Each strike was 20 times. When the golf ball after hitting was visually observed, it was found that the scratches were more conspicuous in the first hemisphere. In this experiment, the scratch resistance of two types of dimple patterns can be evaluated with one type of golf ball. In this experiment, two types of dimple patterns can be evaluated without being affected by variations in physical properties of the core and the cover.

  In the golf ball according to the present invention, various performances can be easily and objectively evaluated.

2, 17 ... Golf ball 4, 18 ... Core 6, 20 ... Cover 6a ... First hemisphere of cover 6b ... Second hemisphere of cover 8, 24 ... Center 10, 26 ... Intermediate layer 12 ... Dimple 14 ... Land 16a, 16b ... Half shell 22 ... Paint layer 22a ... First hemisphere of paint layer 22b ... Second hemisphere of paint layer

Claims (22)

  A golf ball comprising a core and a cover, wherein the cover comprises a first hemisphere and a second hemisphere, and the specification of the first hemisphere is different from the specification of the second hemisphere.   The first hemisphere is made of a first resin composition, the second hemisphere is made of a second resin composition, and the composition of the first resin composition is different from the composition of the second resin composition. The golf ball described in 1.   The first hemisphere is made of a first resin composition, the second hemisphere is made of a second resin composition, and the base resin of the first resin composition is different from the base resin of the second resin composition. The golf ball according to claim 1 or 2.   The first hemisphere is made of a first resin composition, the second hemisphere is made of a second resin composition, and the hardness of the first resin composition is different from the hardness of the second resin composition. 4. The golf ball according to any one of items 1 to 3.   The first hemisphere comprises a first resin composition based on polyurethane, the second hemisphere comprises a second resin composition based on another polyurethane, and the polyurethane polyol of the first resin composition The golf ball according to claim 1, wherein the molecular weight of the component is different from the molecular weight of the polyol component of the polyurethane of the second resin composition.   The golf ball according to claim 2, wherein a main component of the base resin of the first resin composition is polyurethane, and a main component of the base resin of the second resin composition is an ionomer resin.   The golf ball according to claim 2, wherein the first resin composition contains an additive, and the second resin composition contains another additive.   The golf ball according to claim 7, wherein the first resin composition contains an ultraviolet absorber, and the second resin composition contains another ultraviolet absorber.   The golf ball according to claim 7, wherein the first resin composition contains a light stabilizer and the second resin composition contains another light stabilizer.   The golf ball according to claim 7, wherein the first resin composition contains a specific gravity adjusting agent, and the second resin composition contains another specific gravity adjusting agent.   The first resin composition and the second resin composition contain an additive, and the content of the additive in the first resin composition is different from the content of the additive in the second resin composition. The golf ball according to claim 2.   The golf ball according to claim 11, wherein the additive is an ultraviolet absorber, a light stabilizer, or a specific gravity adjuster.   The first hemisphere has one or more layers, the second hemisphere has one or more layers, and the number of layers in the first hemisphere is the number of layers in the second hemisphere. The golf ball according to claim 1, which is different from the number.   The golf ball according to claim 1, wherein the cover has a number of dimples on a surface thereof, and a dimple pattern of the first hemisphere is different from a dimple pattern of the second hemisphere.   A golf ball comprising a core, a cover, and a paint layer, the paint layer comprising a first hemisphere and a second hemisphere, wherein the specification of the first hemisphere is different from the specification of the second hemisphere.   The first hemisphere is made of a first resin composition, the second hemisphere is made of a second resin composition, and the composition of the first resin composition is different from the composition of the second resin composition. The golf ball described in 1.   The golf ball according to claim 16, wherein the first resin composition contains a glitter pigment, and the second resin composition contains another glitter pigment.   The first resin composition and the second resin composition contain a bright pigment, and the content of the bright pigment in the first resin composition is the content of the bright pigment in the second resin composition. The golf ball according to claim 16, which is different from   The golf ball according to claim 15, wherein the hardness of the first hemisphere is different from the hardness of the second hemisphere.   The golf ball according to claim 15, wherein a thickness of the first hemisphere is different from a thickness of the second hemisphere. A process for producing a golf ball comprising a core and a cover, the cover comprising a first hemisphere and a second hemisphere, wherein the specifications of the first hemisphere are different from the specifications of the second hemisphere;
A step of testing the golf ball;
And a method for evaluating a golf ball cover, comprising the step of comparing the performance of the specifications of the first hemisphere with the performance of the specifications of the second hemisphere. A process for producing a golf ball comprising a core, a cover and a paint layer, the paint layer comprising a first hemisphere and a second hemisphere, wherein the specification of the first hemisphere is different from the specification of the second hemisphere;
A step of testing the golf ball;
And a method for evaluating a paint layer of a golf ball, comprising comparing the performance of the specifications of the first hemisphere with the performance of the specifications of the second hemisphere.

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