Abstract: The present invention is a method for manufacturing a golf ball including a core, at least one intermediate layer, and a cover, the core being formed of a rubber material, the intermediate layer being formed of a resin composition, and the cover being formed of a urethane resin material, the method including: a step (1) of forming an intermediate layer-encased sphere by encasing the core with the at least one intermediate layer; a step (2) of subjecting the intermediate layer-encased sphere to a heat treatment at a temperature of at least a melting point of a base resin of the resin composition of the intermediate layer and less than 160° C.; and a step (3) of thereafter forming a cover-encased sphere by encasing the intermediate layer- encased sphere with the cover.

Abstract: In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer and a cover, the core is formed of one or more layer of a rubber composition; the envelope layer, intermediate layer and cover are each formed of a single layer of resin material; the hardness relationship among the layers satisfies the following two conditions: material hardness of cover>material hardness of intermediate layer, and material hardness of envelope layer?surface hardness of core; the ball additionally satisfies the condition: envelope layer thickness (mm)×envelope layer material hardness (Shore D hardness) cover thickness (mm)×cover material hardness (Shore D hardness); and the core and ball have optimized deflections when subjected to a specific loading. This ball serves as a distance ball which enables a superior distance to be achieved on full shots with a driver and with irons.

Abstract: A method for manufacturing a golf ball having a core and a cover of at least one layer includes the step of molding the cover layer with a vertically separating two-part injection mold which has a spherical cavity and three or more support pins disposed so as to be capable of advancing and retracting in a direction perpendicular to a mold parting line, each support pin being housing in a pin housing hole having a nitrided inner peripheral sidewall. This method enables a golf ball cover material to be molded using an injection mold which, because a thick plating of hard chrome does not need to be applied to the inner peripheral sidewalls of the holes housing the support pins, is inexpensive and in which the pin housing holes have a good abrasion resistance.

Abstract: In a golf ball having a core composed of one or more layer, the outermost layer of the core is formed of a rubber composition containing an ?,?-unsaturated metal carboxylate, and an envelope layer directly encasing the core is formed of a resin composition containing a thermoplastic resin having a structure that includes ?,?-ethylenically unsaturated carboxylic acid copolymerization units. The infrared absorption spectra at surface sites on the outermost layer of the core, as measured by ATR FT-IR spectroscopy, satisfy a specific condition. The ball has an enhanced adhesion between the rubber-based core and the adjacent cover layer that is formed of an ionomer resin or other ?,?-ethylenically unsaturated carboxylic acid copolymer-containing resin material.

Abstract: In a golf ball having a rubber core of at least one layer and a cover of at least one layer encasing the core, at least one layer of the cover is formed of a resin composition that includes (I) a polyurethane or a polyurea and (II) a (meth)acrylic block copolymer, and the CS1 value calculated by formula (1) below CS 1 = ( CV 50 - CV 12 ) / 38 ( 1 ) (wherein CV50 is the coefficient of restitution at an incident velocity of 50.0 m/s and CV12 is the coefficient of restitution at an incident velocity of 12.0 m/s) is larger than ?4.08×10?3. The golf ball has an excellent controllability on approach shots and is able to maintain a good scuff resistance and moldability.

Abstract: A foam composition that includes a polymer material such as polyurethane or polyurea and a leachable water-soluble fine powder is provided. This composition can be used in a relatively simple process to obtain a foam body (porous body) that is uniform only at the surface or uniform throughout. The foam body can be suitably used as a golf ball member in golf balls required to have good controllability on approach shots. Also provided is a method for producing a foam member, which method includes the steps of molding the foam composition to obtain a solid molded body, and then leaching out and removing the water-soluble fine powder so as to obtain a foam-molded body.

Abstract: A golf club head according to the disclosure is a cavity-back iron type golf club head that includes a face portion, a cavity portion provided behind the face portion, and a protrusion provided on a lower part of a rear face of the face portion. The protrusion includes a first recess extending from an upper surface of the protrusion toward a sole, a second recess positioned closer to a toe than the first recess is and extending from the upper surface of the protrusion toward the sole, and a thick portion provided between the first and second recesses in a toe-heel direction. The first and second recesses each has a substantially trapezoidal shape in a cross-sectional view taken along a plane that is parallel to a front face of the face portion and passes through a deepest part of each of the first and second recesses.

Abstract: A golf club head according to the disclosure is a cavity-back iron type golf club head that includes a face portion and a back portion. The face portion includes a front face and a rear face facing away from each other, the front face being a ball-striking face. A non-metallic member is fixed to the rear face. An abutment portion including a tip portion with a curved surface is provided on the back portion. The abutment portion is passed through the back portion, and the curved surface of the tip portion contacts the non-metallic member.

Abstract: In a golf ball for professional golfers and skilled amateurs which has a single-layer core, a cover and at least one intermediate layer therebetween, the core is molded from a rubber composition that includes a base rubber, an unsaturated carboxylic acid and/or metal salt thereof, an organic peroxide and, in a specific weight ratio, water and sulfur, and has a hardness profile which satisfies certain specific conditions. The ball achieves an excellent distance on full shots with a driver (W #1) and a middle iron, and is designed for high controllability in the short game.

Abstract: A golf ball according to the present invention includes a core, a cover located outside the core and having a plurality of dimples, and a coating layer located outside the cover and containing a delusterant, the surface of the coating layer having an average roughness Ra of at least 0.35. The surface of the golf ball has a static friction coefficient of at least 0.20. A method for producing a golf ball according to the present invention includes forming a coating layer on the surface of a cover having a plurality of dimples by using a coating material composition including a polyurethane coating material, a delusterant, and a solvent having a boiling point of at least 130° C.

Abstract: A golf ball is provided which suppresses twisting due to external forces while maintaining sufficient deflection at the time of impact, reduces the spin rate without lowering ball rebound, and is thus able to effectively increase the distance traveled by the ball, particularly on shots with a driver. In the golf ball, which includes a core and a cover, the core has a core body made of a first polybutadiene rubber and having a surface with a plurality of groves or holes thereon, which grooves or holes are filled with a second polybutadiene rubber of a differing composition from the first polybutadiene rubber. The polybutadiene rubber-filled groove portions or hole portions have a higher surface hardness than the core body.

Abstract: A multi-piece solid golf ball includes a core, an intermediate layer, and a cover, in which the core is formed of a rubber composition, the intermediate layer and the cover are formed of a resin composition, and a specific gravity of the intermediate layer is set to at least 1.05, or a relationship among a core surface hardness, a surface hardness of an intermediate layer-encased sphere, and a ball surface hardness satisfies the following condition: ball surface hardness<surface hardness of intermediate layer-encased sphere>core surface hardness and the core has a specific cross-sectional hardness profile, thereby to have a superior distance on full shots with clubs from a driver to an iron, good durability on repeated impact, and good controllability in the short game when used by amateur users who are advanced players.

Abstract: A golf ball includes a core, an intermediate layer, and a cover, in which an initial velocity is not more than 76.0 m/s, a deflection when the ball is compressed under a specific load is at least 2.8 mm, and letting a value of (initial velocity of core×weight of core) be Ciw, a value of [(initial velocity of intermediate layer-encased sphere?initial velocity of core)×(weight of intermediate layer-encased sphere?weight of core)] be Miw, and a value of [(initial velocity of ball?initial velocity of intermediate layer-encased sphere)×(weight of ball?weight of intermediate layer-encased sphere)] be CViw, the condition is of Ciw+Miw+CViw?2,550 is satisfied, thereby to be capable of making a distance for reducing a distance on shots with a driver and an iron by average hitters smaller.

Abstract: Provided are a golf ball which has a surface that sparkles when exposed to ultraviolet rays even if a naturally derived substance is used as a fluorescent material, and it is environmentally and human friendly, and a resin composition for a cover or a topcoat therefor. A resin composition for a cover or a topcoat of a golf ball of the present invention includes: a resin for a cover or a topcoat; and a plant-derived or alga-derived extract which emits light using an absorbed light as an energy source, as a fluorescent material. In the golf ball of the present invention, the cover or the topcoat is formed by using such a resin composition.

Abstract: The present invention provides a golf ball in which at least one intermediate layer is formed between a core and a cover, wherein an L value (brightness) of the core is not more than 85 in a Lab display based on JIS Z 8722, an L value (brightness) of a sphere (intermediate layer-encased sphere) obtained by encasing the core with the intermediate layer is at least 75 in the Lab display based on JIS Z 8722, a total light transmittance of the intermediate layer at a thickness of 1.0 mm is 1 to 50%, and a color difference ?E between the core and the intermediate layer-encased sphere is at least 10.

Abstract: A rubber composition for golf balls includes (a) a base rubber, relative amounts of (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof and of (c) an organic peroxide that together satisfy a specific condition, and (d) a specific amount of a moisture-providing agent, the latter being a substance which includes on the structure thereof a water constituent other than free water and eliminates moisture under heating or a substance which thermally decomposes under heating, releasing a water constituent. When the hardness difference in the internal hardness profile of a golf ball core made of the composition is large, the ball exhibits a low spin rate on shots, improving the flight performance of the ball, and the durability of the ball to cracking is enhanced.

Abstract: A golf ball includes one or more coating layer on a golf ball surface having a plurality of dimples thereon. At least one coating layer is formed of a two-component curable urethane coating composition having a polyol component and a polyisocyanate component, which polyol component is an acrylic polyol or a polyester polyol. The coating composition contains less than 5 wt % of polyurethane particles, relative to base resin solids within the composition. The coating layer formed on the ball surface suppresses coating sag, improves the film thickness edge ratio between the film thickness at the middle portion and the film thickness at edge portions of the dimples, and has an improved scuff resistance, peel resistance and marking protective effect.

Abstract: A rubber composition for golf balls is provided which, when the hardness difference in the internal hardness profile of a golf ball core made of the composition is set to a large value, enables the ball to exhibit low spin characteristics when hit, improving the flight performance of the ball, and also enhances the ball durability to cracking. The rubber composition includes (a) a base rubber, (b) a co-crosslinking agent that is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide and (d) water, component (d) being included in an amount of from 0.1 to 10 parts by weight per 100 parts by weight of component (a), and components (b) and (c) being included in relative amounts such that E, defined by the formula E=molar amount of component (b)/molar amount of active oxygens in component (c), has a value of 93 or more.

Abstract: The present invention provides a rubber composition for golf balls which includes (a) a base rubber, (b) a co-crosslinking agent being an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) a crosslinking initiator and (d) a specific amount of an anionic surfactant, so that the rubber composition reduces sticking of a molded rubber material made therefrom to the mold and also maintains the resilience and other properties of the molded rubber material.

Abstract: In a golf ball having a core and a cover of one or more layer, the core is a product molded under heat from a rubber composition which includes (a) a base rubber, (b) a co-crosslinking agent which is an ?,?-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, and (d) water, wherein the content of component (d) is set within a specific range and components (b) and (c) are included in relative amounts that satisfy a specific condition. The core has a specific compressive deformation and a specific hardness difference between the center and surface thereof. Owing to the large hardness difference in the internal hardness profile of the core, the ball exhibits low spin characteristics when hit, improving the flight performance, yet retains a good durability to impact.