Abstract: There is provided a method of producing a golf ball, capable of forming a cover to have a uniform thickness to produce a golf ball excellent in resistance to abrasion. The method includes a step to subject a cover material mainly composed of a thermoplastic resin to heat and compression molding to form a half shell, and a step to allow two such half shells to be arranged on a core or an intermediate layer, joined together, and heat and compression molded to mold the cover to have a thickness of 0.3 to 1.5 mm.

Abstract: The present invention provides a multi-piece solid golf ball, which is superior in flight distance, shot feel, controllability and scuff resistance. The present invention relates to a multi-piece solid golf ball comprising a core consisting of a center and an intermediate layer, and a cover having many dimples on the surface thereof, wherein the center has a diameter of 25 to 40 mm, and a surface hardness of the center is higher than a central point hardness of the center in Shore D hardness by not more than 7, the intermediate layer has a thickness of 0.5 to 8.0 mm, and a surface hardness in Shore D hardness of the intermediate layer is higher than the central point hardness of the center by 3 to 25, and a hardness in Shore D hardness of the cover is lower than the surface hardness of the intermediate layer by 0 to 15.

Abstract: A multi-piece golf ball with a two-part curing type polyurethane cover is provided, which is satisfactory in moldability and ball characteristics such as a abrasion resistance and a carry. The multi-piece golf ball according to this invention has a core having an increased diameter and provided with a hardness difference between its surface portion and its central portion. This feature imparts the multi-piece golf ball with such characteristics as a high repulsion property, high shot angle and low spin count, thereby making the golf ball ensure an increased carry. The polyurethane cover of the multi-piece golf ball, which is formed from a two-part curing type polyurethane including a specific isocyanate group-terminated urethane prepolymer and an aromatic polyamine compound, is excellent in durability and abrasion resistance.

Abstract: There is provided a method of producing a golf ball, eliminating defective air between the cover and the core, an insufficient thickness of the cover and an uneven thickness of the cover to provide the cover with a uniform thickness. In the method at the step of heat and compression molding to cover the core or an intermediate layer with half shells molded from a cover material mainly composed of a thermoplastic resin, if the mold has a temperature of T1° C. and the half shells start to flow at a temperature of T2° C., T1 minus T2 is set within a range of −3° C. to +10° C.

Abstract: The present invention provides a three-piece solid golf ball having long flight distance, by accomplishing high launch angle and low spin amount immediately after hitting, while maintaining soft and good shot feel when hitting at low head speed. The present invention relates to a three-piece solid golf ball comprising a center, an intermediate layer formed on the center, and an outer layer covering the intermediate layer, wherein the center has a central point hardness in JIS-C hardness of 55 to 75 and a surface hardness in JIS-C hardness of 65 to 85, the surface hardness is higher than the central point hardness by 10 to 20, a JIS-C hardness of the intermediate layer is higher than the surface hardness of the center by 10 to 20, and a JIS-C hardness of the outer layer is higher than the hardness of the intermediate layer by 5 to 15.

Abstract: The present invention provides a solid golf ball having long flight distance obtained by accomplishing high launch angle and low spin amount, and having excellent shot feel, rebound characteristics, scuff resistance and yellowing resistance. The present invention relates to a solid golf ball comprising a core and a cover formed on the core, wherein the cover comprises as a base resin (a) polyurethane-based thermoplastic elastomer formed by using cycloaliphatic diisocyanate, or (b) a mixture of polyurethane-based thermoplastic elastomer formed by using cycloaliphatic diisocyanate and polyamide-based thermoplastic elastomer, and has a thickness of not more than 1.0 mm, and a surface hardness in Shore D hardness of the core is higher than a central point hardness in Shore D hardness of the core by not less than 20.

Abstract: The present invention provides a golf ball having excellent scuff resistance. The present invention relates to a golf ball comprising at least one layer of a core and a cover covering the core, wherein the cover is formed from a material having a value of the maximum load of 1.5 to 3.0 kN at an impact energy of 47.3 J in penetration and impact fatigue tests.

Abstract: The present invention provides a multi-piece solid golf ball, which is superior in rebound characteristics, flight performance and durability, while maintaining good productivity. The present invention relates to a multi-piece solid golf ball comprising a core, an intermediate layer formed on the core and a cover covering the intermediate layer, wherein the intermediate layer is formed from an intermediate layer composition comprising a functional group modified resin as a main component, the cover is formed from a cover composition comprising a resin having polar site that can react with the functional group of the functional group modified resin in the intermediate layer as a main component, and a hardness of the intermediate layer is lower than that of the cover.

Abstract: The present invention provides a multi-piece solid golf ball, of which durability is excellent and flight distance is improved by accomplishing high launch angle and low spin amount, when hit by golfers, who swing a golf club at low head speed, using a middle iron club to a driver. The present invention relates to a multi-piece solid golf ball comprising a center, an intermediate layer formed on the center and a cover covering the intermediate layer, wherein the intermediate layer is formed from a material having an elongation of 9 to 20 mm when applying the maximum load in penetration and impact fatigue tests and a flexural stiffness of 300 to 2,000 MPa.

Abstract: To provide superior hit feel, a high coefficient of restitution, superior spin characteristics (controllability) and in addition thereto superior abrasion resistance when it is hit with an iron club, a golf gall includes a center core, an intermediate layer and a cover, wherein: the center core has a diameter of 25 to 40 mm, and a surface hardness (B) and a center hardness (A), the surface hardness (B) being at least 15 greater than the center hardness (A), as measured in Shore D hardness; the intermediate layer has a surface hardness (C) 20 to 50 greater than the center hardness (A) of the center core, as measured in Shore D hardness; the cover has a hardness (D) of 40 to 60, as measured in Shore D hardness; and the surface hardness (C) of the intermediate layer is 5 to 25 greater than the hardness (D) of said cover, as measured in Shore D hardness.

Abstract: The present invention provides a multi-piece solid golf ball, of which flight distance is improved by accomplishing high launch angle and low spin amount, when hit by golfers, who swing a golf club at low head speed, using a middle iron club to a driver. The present invention relates to multi-piece solid golf ball comprising a center, an intermediate layer formed on the center and a cover covering the intermediate layer, wherein the intermediate layer is formed from only one material having a flexural stiffness of 400 to 5,000 MPa.

Abstract: The present invention provides a golf ball having soft and good shot feel, high rebound characteristics and excellent abrasion resistance when hit by an iron club. The present invention related to a golf ball comprising a core and at least one layer of cover covering the core, wherein the outmost layer of the cover is formed from a base resin mainly containing the mixture of (i) ethylene-(meth)acrylic acid-acrylic ester terpolymer ionomer resin obtained by neutralizing with magnesium ion, (ii) ethylene-(meth)acrylic acid-acrylic ester terpolymer ionomer resin obtained by neutralizing with sodium ion and/or ethylene-(meth)acrylic acid-acrylic ester terpolymer ionomer resin obtained by neutralizing with zinc ion, and (iii) ethylene-(meth)acrylic acid copolymer ionomer resin obtained by neutralizing with magnesium ion, and the outmost layer of the cover has a Shore D hardness of 45 to 60.

Abstract: The present invention provides a method of making a golf ball comprising a core and polyurethane cover. The present invention relates to a method of making a golf ball comprising the steps of: (a) forming a core, and (b) putting polyurethane cover composition into a first half mold and allowing the composition to be made to a given gel state; turning the first mold upside down so as to position it above a core half mold placing the core therein; clamping the molds and press molding to form an intermediate molded article of golf ball; putting the composition into a second half mold and allowing the composition to be made to a given gel state in the same manner as the step (i); positioning the second mold below the first mold; clamping the molds and press molding to cover the other half of the surface of the core with the polyurethane cover.

Abstract: The present invention provides a golf ball having soft and good shot feel, high rebound characteristics and excellent abrasion resistance when hit by an iron club. The present invention related to a golf ball comprising a core and at least one layer of cover covering the core, wherein the outmost layer of the cover is formed from a base resin mainly containing the mixture of (i) ethylene-(meth)acrylic acid-acrylic ester terpolymer ionomer resin obtained by neutralizing with magnesium ion, (ii) ethylene-(meth)acrylic acid copolymer ionomer resin obtained by neutralizing with sodium ion, and (iii) ethylene-(meth)acrylic acid copolymer ionomer resin obtained by neutralizing with zinc ion, and the outmost layer of the cover has a Shore D hardness of 45 to 60.

Abstract: The present invention provides a multi-piece solid golf ball, which is superior in rebound characteristics and flight performance, while maintaining good productivity.

Abstract: The present invention provides a golf ball, which is superior in shot feel, rebound characteristics and laminar separation resistance.

Abstract: There is provided a solid golf ball comprising a multi-piece core and a cover made from polyurethane obtained by curing an isocyanate group-terminated urethane prepolymer including a residual polyisocyanate monomer content of not more than 0.1% by mass using an aromatic polyamine curing agent. The golf ball satisfies moldability of the polyurethane cover and durability, and exhibits excellent ball characteristic such as flight performance and shot feeling.

Abstract: Golf ball 1 has a core 2 and a cover 3. The cover 3 is formed from a polymer composition. A coefficient of loss at −20° C., T(−20), and a complex elastic modulus at −20° C.

Abstract: There is provided a solid golf ball comprising a core and a cover made from polyurethane obtained by curing an isocyanate group-terminated urethane prepolymer including a residual polyisocyanate monomer content of not more than 0.1% by mass using an aromatic polyamine curing agent. The golf ball satisfies moldability of the polyurethane cover and durability, and exhibits excellent ball characteristic such as flight performance and shot feeling.

Abstract: The present invention provides a multi-piece solid golf ball, which is superior in rebound characteristics, flight performance and durability, while maintaining good productivity.