Abstract: An object of the present invention is to provide a golf ball excellent in hitting durability. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein at least a part of the spherical core is formed from a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (x) an olefin-alkyl (meth)acrylate copolymer, and a content of (x) the olefin-alkyl (meth)acrylate copolymer in the rubber composition ranges from 0.5 part by mass to 7.0 parts by mass with respect to 100 parts by mass of (a) the base rubber.

Abstract: An object of the present invention is to provide a golf ball showing excellent impact durability. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the golf ball comprises a reinforcing layer containing a polyvinyl acetal resin on the surface of the spherical core.

Abstract: An object of the present invention is to provide a method for manufacturing a golf ball excellent in kneading workability when preparing a core rubber composition containing (d) a carboxylic acid and/or a salt thereof. The present invention provides a method for manufacturing a golf ball comprising the steps of blending (a) a base rubber and at least (b) a carboxylic acid and/or a salt thereof to prepare a first masterbatch; blending (a) a base rubber and at least (c) a crosslinking initiator to prepare a second masterbatch; blending the first masterbatch and second masterbatch to form a core rubber composition; molding the core rubber composition into a spherical core; and forming one or more cover layers covering the spherical core.

Abstract: An object of the present invention is to provide a novel method of manufacturing a golf ball comprising forming a spherical core having less-variable compression deformation amount and stabilized properties. The present invention provides a method for manufacturing a golf ball, comprising the steps of: blending (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, (d) a carboxylic acid and/or a salt thereof having a number-average particle size ranging from 15 ?m to 60 ?m, and (e) where necessary a metal compound to prepare a core rubber composition; molding the core rubber composition into a spherical core under specific conditions; and forming at least one cover layer on the spherical core.

Abstract: An object of the present invention is to provide a golf ball providing a great distance. Another object of the present invention is to provide a golf ball striking a balance between a flight distance on a driver shot and an approach performance on an approach shot while providing an excellent shot feeling.

Abstract: An object of the present invention is to provide a golf ball comprising a core formed from a rubber composition containing (d) a carboxylic acid and/or a salt thereof and traveling a great flight distance on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, (d) a carboxylic acid and/or a salt thereof and two or more kinds of (e) organic sulfur compounds, provided that the rubber composition further contains (f) a metal compound in case of containing only (b) the ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms as the co-crosslinking agent.

Abstract: An object of the present invention is to provide a golf ball showing excellent impact durability. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the golf ball comprises a reinforcing layer containing a polyvinyl acetal resin on the surface of the spherical core.

Abstract: An object of the present invention is to provide a golf ball excellent in hitting durability. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein at least a part of the spherical core is formed from a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent, (c) a crosslinking initiator, and (x) an olefin-alkyl (meth)acrylate copolymer, and a content of (x) the olefin-alkyl (meth)acrylate copolymer in the rubber composition ranges from 0.5 part by mass to 7.0 parts by mass with respect to 100 parts by mass of (a) the base rubber.

Abstract: The present invention provides a golf ball having a center and at least one intermediate layer covering the center and a cover, wherein at least one of the intermediate layer is formed from a composition comprising, as a resin component, (A) a polyamide copolymer containing (a-1) a polymerized fatty acid, (a-2) sebacic acid and/or azelaic acid, (a-3) a polyamine component as an essential component, and (B) at least one member selected from (b-1) a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid, (b-2) a metal ion-neutralized product of a binary copolymer composed of an olefin and an ?,?-unsaturated carboxylic acid, (b-3) a ternary copolymer composed of an olefin, an ?,?-unsaturated carboxylic acid and an ?,?-unsaturated carboxylic acid ester, and (b-4) a metal ion-neutralized product of a ternary copolymer composed of an olefin, an ?,?-unsaturated carboxylic acid and an ?,?-unsaturated carboxylic acid ester.

Abstract: An object of the present invention is to provide a golf ball excellent in resilience and durability, with a good moldability of the intermediate layer. The present invention provides a golf ball having a center, a cover, and an intermediate layer disposed between the center and the cover, wherein the intermediate layer is formed from an intermediate layer composition having a flexural modulus ranging from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a rebound resilience of 55% or more, and a slab hardness ranging from 40 to 60 in Shore D hardness, and the intermediate layer composition comprises, as a resin component, 30 mass % to 70 mass % of (A) a modified polyester elastomer having a Shore A hardness of 95 or less; 70 mass % to 30 mass % of (B) a binary ionomer resin having a Shore D hardness of 65 or more, a flexural modulus of 300 MPa or more, and a melt flow rate (190° C., 2.16 kg) of 1.

Abstract: An object of the present invention is to provide a golf ball having a spherical core with an outer-hard inner-soft structure formed from a rubber composition excellent in kneading workability. Another object of the present invention is to provide a golf ball traveling a great flight distance on driver shots. The present invention provides a golf ball having a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, and (d) a basic metal salt of a fatty acid.

Abstract: An object of the present invention is to provide a golf ball having an excellent properties like flight distance and low temperature durability. The present invention provides a golf ball comprising: a core consisting of a center and one or more intermediate layers covering the center; and a cover covering the core, wherein at least one piece or one layer of said intermediate layers is formed from a highly elastic intermediate layer composition that contains (A) a highly elastic polyamide resin having a flexural modulus in a range from 700 MPa to 5,000 MPa; (B) a metal-neutralized product of ethylene-(meth)acrylic acid copolymer and (C) a resin having a polar functional group in a specific way.

Abstract: An object of the present invention is to provide a golf ball that decrease the spin rate on the driver shots while suppressing the decrease in the spin rate on the approach shots in a golf ball having a urethane cover. The present invention provides a golf ball having a core consisting of a center and at least one intermediate layer covering the center, and a cover covering the core, wherein the cover contains polyurethane, and has a slab hardness of 85 or less in JIS A hardness, the core has a surface hardness of 60 or more in Shore D hardness, the intermediate layer has a thickness ranging from 0.5 mm to 2.0 mm, and a resin component constituting the intermediate layer has a hardness from 62 to 68 in Shore D hardness, a flexural modulus from 300 MPa to 500 MPa, and a maximum storage modulus E? between ?30° C. to 0° C. ranging from 1,000 MPa to 2,000 MPa.

Abstract: An object of the present invention is to provide a golf ball having an improved controllability and shot feeling while maintaining a flight distance on driver shots. The present invention provides a golf ball having a core, an intermediate layer disposed around the core, and a cover disposed around the intermediate layer, wherein the core has a center and an envelope layer disposed around the center, and has a specific hardness distribution, and the intermediate layer is formed from an intermediate layer composition comprising, as a resin component, (A) a modified polyester elastomer and (B) a binary ionomer resin, and having a flexural modulus ranging from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a repulsive modulus of 55% or more, and a slab hardness ranging from 60 to 90 in JIS-hardness.

Abstract: A center of a golf ball is formed from a composition having a flexural modulus from 150-450 MPa, a maximum loss factor (tan ?) between ?20 and 0° C. of 0.08 or less, a rebound resilience of 55% or more, and a slab hardness ranging from 40-60 in Shore D hardness. The center composition includes, as a resin component, 30 to 70 mass % of (A) a modified polyester elastomer having a Shore A hardness of 95 or less; 70-30 mass % of (B) a binary ionomer resin having a Shore D hardness of 65 or more, a flexural modulus of 300 MPa or more, and a melt flow rate (190° C., 2.16 kg) of 1.0 g/10 min or more; and 0-50 mass % of (C) a thermoplastic resin other than (A) and (B) components (provided that a total content of (A), (B), and (C) components is 100 mass %).

Abstract: The present invention provides a golf ball comprising a core and a cover covering the core, wherein the cover is formed from a cover composition containing a non-petroleum based polyester resin as a resin component (A) and a needle-like and/or fibrous filler (B). The present invention further provide a golf ball comprising a core and a cover covering the core, wherein the cover is formed from a cover composition containing, a non-petroleum based polyester resin (A-1), at least one petroleum based thermoplastic resin (A-2), and a compatibilizer (C) containing at least a (meth)acrylic resin (C-1) having a polar functional group and an olefin resin (C-2) having a polar functional group. According to the present invention, durability, abrasion resistance and repulsion of a golf ball can be improved.

Abstract: The present invention is directed to a golf ball having a center, an envelope layer, an intermediate layer and a cover, wherein the intermediate layer has a thickness less than 1.2 mm, the envelope layer has a hardness Hs of 60 or more, the intermediate layer has a hardness Hm from 40 to 60, and the cover has a hardness Hc less than 40 in Shore D hardness, and the hardness Hs, Hm and Hc satisfy a following mathematical expression: Hs>Hm>Hc, and the intermediate layer composition has a flexural modulus from 150 MPa to 450 MPa, a maximum loss factor (tan ?) between ?20° C. and 0° C. of 0.08 or less, a rebound resilience of 55% or more.

Abstract: A golf ball 2 includes a core 4, a mid layer 6, and a cover 8. The difference between: a hardness H(5.0) at a point located at a distance of 5 mm from the central point of the core 4; and a hardness Ho at the central point is 6.0 or greater. The difference between: a hardness H(12.5) at a point 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 core 4 and 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. In the core 4, there is no zone in which a hardness decreases from the central point to the surface. A hardness H3 of the cover 8 is greater than a hardness H2 of the mid layer 6. The cover 8 is formed from a resin composition containing a polyamide copolymer including a polymerized fatty acid (a-1), sebacic acid and/or azelaic acid (a-2), and a polyamine component (a-3).

Abstract: An object of the present invention is to provide a novel method of manufacturing a golf ball comprising forming a spherical core having less-variable compression deformation amount and stabilized properties. The present invention provides a method for manufacturing a golf ball, comprising the steps of: blending (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, (d) a carboxylic acid and/or a salt thereof having a number-average particle size ranging from 15 ?m to 60 ?m, and (e) where necessary a metal compound to prepare a core rubber composition; molding the core rubber composition into a spherical core under specific conditions; and forming at least one cover layer on the spherical core.

Abstract: An object of the present invention is to provide a golf ball comprising a core formed from a rubber composition containing (d) a carboxylic acid and/or a salt thereof and traveling a great flight distance on driver shots. The present invention provides a golf ball comprising a spherical core and at least one cover layer covering the spherical core, wherein the spherical core is formed from a rubber composition containing (a) a base rubber, (b) an ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms and/or a metal salt thereof as a co-crosslinking agent, (c) a crosslinking initiator, (d) a carboxylic acid and/or a salt thereof and two or more kinds of (e) organic sulfur compounds, provided that the rubber composition further contains (f) a metal compound in case of containing only (b) the ?,?-unsaturated carboxylic acid having 3 to 8 carbon atoms as the co-crosslinking agent.