Sri Sports Limited

Dunlop Sports Company Limited

Sumitomo Rubber Industries Limited

Mitsubishi Chemical Corporation

Kazuhiko Isogawa

Koichi Fujisawa

Kosuke Tachibana

Seiichiro Endo

Tsutomu Hirau

Keiji Ohama

Masatoshi Yokota

Hirotaka Nakamura

Yoshikazu Yabuki

Satoko Okabe

Toshiyuki Tarao

Keiji Moriyama

Takahiro Shigemitsu

Takashi Sasaki

Masaaki Kikuchi

Takahiro Sajima

Yoshiko Matsuyama

Kuniyasu Horiuchi

Akira Kato

Kazuya Kamino

Yoshinori Sano

Kazuhisa Fushihara

Hyoungchol Kim

Hirokazu Okamoto

Masahiko Shiraishi

Keiko Matsuhisa

A golf ballincludes a core, a first mid layer, a second mid layer, and a cover. The coreincludes a centerand an envelope layer. The centeris formed by crosslinking a first rubber composition, and the envelope layeris formed by crosslinking a second rubber composition. The first rubber composition or the second rubber composition includes a base rubber, a co-crosslinking agent, a crosslinking initiator, and an acid and/or a salt. The co-crosslinking agent is:

Golf ball

A golf ballincludes a core, amid layer, a reinforcing layer, and a cover. The coreincludes a centerand an envelope layer. The envelope layeris formed by a rubber composition being crosslinked. The rubber composition includes a base rubber (a), a co-crosslinking agent (b), a crosslinking initiator (c), and an acid and/or a salt (d). The co-crosslinking agent (b) is:

The present invention provides a golf ball comprising a spherical core composed of a spherical inner core layer and an outer core layer, an intermediate layer and a cover, wherein the inner core layer has a hardness difference (Hs1&#x2212;Ho) between a surface hardness (Hs1) and a center hardness (Ho) of 5 or less in JIS-C hardness, the outer core is such that Rof a linearly approximated curve obtained from a least square method is 0.95 or higher, when JIS-C hardness, measured at nine points obtained by dividing a thickness of the outer core in a radius direction of the spherical core into equal parts having 12.5% intervals therebetween, is plotted against distance (%) from a border point between the outer core layer and the inner core layer, and the intermediate layer has a slab hardness which is greater than a slab hardness of the cover.

A golf ball includes a spherical core, a mid layer, an inner cover, and an outer cover. A hardness Hm of the mid layer is greater than a hardness Hinc of the inner cover which is greater than a hardness Houc of the outer cover. A difference (Hm&#x2212;Houc) is greater than 25. A volume Vm of the mid layer is greater than a volume Vinc of the inner cover which is greater than a volume Vouc of the outer cover. A ratio [(Vm+Vinc+Vouc)/V] of a sum (Vm+Vinc+Vouc) relative to a volume V of an entirety of the golf ball is less than 0.30. A ratio (Vm/Vouc) is greater than 1.50. A product (Vm*Hm) and a product (Vouc*Houc) meet the following relationship: [(Vm*Hm)/(Vouc*Houc)]&#x3e;3.0.

Provided is a golf ball is excellent in flight distance performance, approach performance, and feel at impact. A ballincludes a core, a mid layer, and a cover. The coreincludes an inner coreand an outer core. The coverincludes an inner layer coverand an outer layer cover. An inner core volume Vc, a mid layer volume Vm, a mid layer hardness Hm, an inner layer cover volume Vinc, an inner layer cover hardness Hinc, an outer layer cover volume Vouc, an outer layer cover hardness Houc, and a ball volume V meet the following relational expressions (a) to (g): (a) Vc/V&#x3c;0.07, (b) Hm&#x3e;Hinc&#x3e;Houc, (c) Hm&#x2212;Houc&#x3e;25, (d) Vm&#x3e;Vinc&#x3e;Vouc, (e) (Vm+Vinc+Vouc)/V&#x3c;0.30, (f) Vm/Vouc&#x3e;1.50, and (g) (Vm*Hm)/(Vouc*Houc)&#x3e;3.0.

A golf ball includes a core, a mid layer, and a cover. The core includes an inner core, a mid core, and an outer core. The mid layer includes an inner mid layer and an outer mid layer. A hardness H(C) is equal to or greater than a hardness H(B). A hardness H(E) is equal to or greater than a hardness H(D). An angle &#x3b1; is calculated by (Formula 1). An angle &#x3b2; is calculated by (Formula 2). The angle &#x3b1; is 0&#xb0; or greater. A difference (&#x3b1;&#x2212;&#x3b2;) is 0&#xb0; or greater. A hardness Hmof the outer mid layer is greater than a hardness Hmof the inner mid layer.&#x3b1;=(180&#xb0;/&#x3c0;)*tan [{()&#x2212;()}/]&#x2003;&#x2003;(Formula 1)&#x3b2;=(180&#xb0;/&#x3c0;)*tan [{()&#x2212;()}/]&#x2003;&#x2003;(Formula 2)

An object of the present invention is to provide a golf ball striking a good balance between flight distance on driver shots and spin rate on approach shots, and excellent in stain resistance and shot feeling. The present invention provides a golf ball comprising a paint film, wherein a base resin of the paint film contains a polyurethane obtained by a reaction between a polyisocyanate composition and a polyol composition containing a urethane polyol having a polyether diol with a number average molecular weight in a range from 800 to 3,000 as a constituent component, and the following requirements are satisfied:Mp&#x2266;200&#xd7;&#x2212;75Mp&#x2266;100Minm&#x2212;Moum&#x3e;40Moum&#x2212;Mc&#x3c;5Tinm&#x2267;Toum&#x3e;Tc&#x3e;Tp(Tinm&#xd7;Minm)/(Toum&#xd7;Moum)&#x3e;2.0(Toum&#xd7;Moum)/(Tc&#xd7;Mc)&#x3c;3.0(Tc&#xd7;Mc)/(Tp&#xd7;Mp)&#x3e;10.0[where Mp, Minm, Moum, and Mc represent a 10% elastic modulus (kgf/cm) of the paint film, inner intermediate layer, outer intermediate layer and cover, respectively; Tp, Tinm, Toum, and Tc represent a thicknesses (mm) of the paint film, inner intermediate layer, outer intermediate layer and cover, respectively; and X represents a molar ratio (NCO/OH) of a NCO group in the polyisocyanate composition to a OH group in the polyol composition.].

A golf ballincludes a spherical core, a mid layer, and a cover. The coreis obtained by crosslinking a rubber composition. The difference between: a hardness H(5.0) at a point which is located at a distance of 5 mm from the central point of the core; and a hardness Ho at the central point is 6.0 or greater. The difference between: a hardness H(12.5) at a point which is located at a distance of 12.5 mm from the central point; and the hardness H(5.0) is 4.0 or less. The difference between a hardness Hs at the surface of the coreand the hardness H(12.5) is 10.0 or greater. The difference between the hardness Hs and the hardness Ho is 22.0 or greater. There is no zone in which a hardness decreases from the central point to the surface. A Shore D hardness H3 of the cover is greater than a Shore D hardness H2 of the mid layer.

A golf ballincludes a core, a first mid layer, a second mid layer, a third mid layer, and a cover. A volume Vinm and a Shore D hardness Hinm of the first mid layer, a volume Vm and a Shore D hardness Hm of the second mid layer, a volume Voum and a Shore D hardness Houm of the third mid layer, a volume Vc and a Shore D hardness Hc of the cover, and a volume V of an entirety of the ball meet: (a) Hinm&#x3c;Hm&#x3e;Houm&#x3e;Hc, (b) Vinm&#x3c;Vm&#x3e;Voum&#x3e;Vc, (c) Hm&#x2212;Hc&#x3e;25, (d) (Vinm+Vm+Voum+Vc)/V&#x3c;0.40, (e) Vm/Vc&#x3e;1.50, and (f) (Vm*Hm)/(Vc*Hc)&#x3e;3.0.

A golf ball includes a spherical core and a cover. The core includes an inner core, a mid core, and an outer core. A hardness H(C) is equal to or greater than a hardness H(B). A hardness H(E) is equal to or greater than a hardness H(D). An angle &#x3b1; is calculated by (Formula 1) from a thickness Y (mm) of the mid core, the hardness H(C), and the hardness H(D). An angle &#x3b2; is calculated by (Formula 2) from a thickness Z (mm) of the outer core, the hardness H(E), and the hardness H(F). Each of the angle &#x3b1; and a difference (&#x3b1;&#x2212;&#x3b2;) between the angles &#x3b1; and &#x3b2; is equal to or greater than 0&#xb0;. The golf ball has excellent flight performance upon a shot with a driver.&#x3b1;=(180/&#x3c0;)*tan [{()&#x2212;()}/&#x2003;&#x2003;(Formula 1)&#x3b2;=(180/&#x3c0;)*tan [{()()&#x2003;&#x2003;(Formula 2)

A golf ball includes an intermediate layer, a cover, and a paint film, wherein a base resin of the paint film is a polyurethane obtained by a reaction between a polyisocyanate composition and a polyol composition containing a urethane polyol including a polyether diol with a number average molecular weight ranging from 800 to 3000 as a constituent component, and the golf ball satisfies the following requirements;&#x2266;200&#xd7;&#x2212;75Mp&#x2266;100&#x3e;100Tm&#x3e;Tc&#x3e;Tp()/()&#x3e;7.5()/()&#x3e;2.4.[Mp, Mm and Mc represent 10% modulus (kgf/cm) of the paint film, intermediate layer and cover, respectively; Tp, Tm and Tc represent thicknesses (mm) of the paint film, intermediate layer and cover, respectively; and X represents a molar ratio (NCO/OH).]

An object of the present is to provide a golf ball having a high spin rate on approach shots under the wet condition and rough condition. The present invention provides a golf ball comprising a golf ball body, and a paint film formed on a surface of the golf ball body, wherein the paint film has a martens hardness of 2.0 mgf/&#x3bc;mor less, and a ratio (50% modulus/10% modulus) of 50% modulus to 10% modulus of 1.6 or more.

A golf ball includes a core, a mid layer, and a cover. The core includes an inner core, a mid core, and an outer core. The mid layer includes an inner mid layer and an outer mid layer. A hardness H(C) is equal to or greater than a hardness H(B). A hardness H(E) is equal to or greater than a hardness H(D). An angle &#x3b1; is calculated by (Formula 1). An angle &#x3b2; is calculated by (Formula 2). The angle &#x3b1; is 0&#xb0; or greater. A difference (&#x3b1;&#x2212;&#x3b2;) is 0&#xb0; or greater. A hardness Hm2 of the outer mid layer is less than a hardness Hm1 of the inner mid layer. A hardness Hc of the cover is less than the hardness Hm2.&#x3b1;=(180&#xb0;/&#x3c0;)*tan [{()&#x2212;()}/&#x2003;&#x2003;(Formula 1)&#x3b2;=(180&#xb0;/&#x3c0;)*tan [{()&#x2212;()}/&#x2003;&#x2003;(Formula 2)

The present invention provides a golf ball comprising a golf ball body with a spherical core having one or more layers, an intermediate layer disposed outside the spherical core and a cover disposed outside the intermediate layer and a paint film formed on a surface of the golf ball body, and having a friction coefficient calculated using a contact force tester of 0.35 or more and 0.60 or less, wherein the golf ball body has specific plurality of dimples on the surface thereof, at least one layer of the spherical core is a rubber layer having a specific hardness distribution, and the rubber layer has a hardness at the outermost point which is greater than a hardness at the innermost point, and the intermediate layer has a slab hardness (Hm) which is greater than a slab hardness (Hc) of the cover.

A golf ballincludes a core, a mid layerpositioned outside the core, a reinforcing layerpositioned outside the mid layer, and a coverpositioned outside the reinforcing layer. The coreis obtained by a rubber composition being crosslinked. The rubber composition includes a base rubber, a co-crosslinking agent, a crosslinking initiator, and a carboxylate. The co-crosslinking agent is: (1) an &#x3b1;, &#x3b2;-unsaturated carboxylic acid having 3 to 8 carbon atoms; and/or (2) a metal salt of an &#x3b1;, &#x3b2;-unsaturated carboxylic acid having 3 to 8 carbon atoms. The amount of the carboxylate is equal to or greater than 1.0 parts by weight but less than 40 parts by weight per 100 parts by weight of the base rubber. A hardness of the mid layeris greater than a hardness of the cover

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Kobe, Japan

Kazuhiko Isogawa