A golf ball includes a relatively large polymer core and has a soft ball compression. The polymer is, in the illustrated embodiments, a highly neutralized acid polymer. The golf ball may, optionally, include an outer core made of a different material, such as a thermoset polybutadiene rubber. The golf ball may, optionally, include a mantle layer made of an ionomer material. The inner core having a diameter of between 24 mm and 40 mm, and in some designs, between 28 mm and 32 mm, yields increased iron initial velocity and lower iron spin while maintaining driver performance.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. Polyurethane primer coatings and polyurethane top-coatings are applied to the thermoplastic polyurethane cover. Isocyanate-rich and polyol-rich polyurethane coatings can be applied. In one embodiment, multi-functional imine and amine compounds can be used to treat the golf ball. The resulting coating may contain polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. The cover composition and surface coatings can further include catalysts, ultraviolet (UV)—light stabilizers, and other additives. Heat is used to cure the coatings. The coating methods have many benefits and the finished balls have good physical properties.

A constituent member of a golf ball comprising a vulcanized form of a rubber composition includes (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid and/or a metal salt thereof, (c) an organic peroxide, (d) water, (e) an antioxidant which is a benzoimidazole of the following general formula and/or a metal salt thereof, and (g-1) an organosulfur being alkylphenoldisulfide polymers represented by the specific chemical formula or (h) sulfur. When the rubber composition is used in constituent members of a golf ball, especially the core, the golf ball exhibits low spin properties on shots, resulting in an improved flight performance and enabling a good durability to be maintained.

Golf balls having covers made of thermoplastic polyurethane compositions are provided. Multi-piece golf balls can be made. Polyurethane primer coatings and polyurethane top-coatings are applied to the thermoplastic polyurethane cover. Isocyanate-rich and polyol-rich polyurethane coatings can be applied. In one embodiment, multi-functional imine and amine compounds can be used to treat the golf ball. The resulting coating may contain polyurethanes, polyureas, and hybrids, copolymers, and blends thereof. The cover composition and surface coatings can further include catalysts, ultraviolet (UV)-light stabilizers, and other additives. Heat is used to cure the coatings. The coating methods have many benefits and the finished balls have good physical properties.

An object of the present disclosure is to provide a golf ball having an increased spin rate when being hit with an 8-iron while suppressing rise in a spin rate when being hit with a driver. The present disclosure provides a golf ball comprising a spherical core having an inner core and an outer core, and a cover positioned outside the spherical core, wherein A×a is 12,200 or less and B×b is 20,400 or more, where “a” represents an average hardness (Shore C) of a hardness (H2.5) at a point of 2.5 mm from a center of the spherical core and a hardness (H5) at a point of 5 mm from the center of the spherical core, “b” represents an average hardness (Shore C) of a hardness (H7.5) at a point of 7.5 mm from the center of the spherical core and a hardness (H9) at a point of 9 mm from the center of the spherical core, “A” represents an impulse difference (kN.Math..Math.s) between a back spin impulse and a top spin impulse measured using a contact force tester under a condition corresponding to a condition when the golf ball is hit with a driver, and “B” represents an impulse difference (kN.Math..Math.s) between a back spin impulse and a top spin impulse measured using a contact force tester under a condition corresponding to a condition when the golf ball is hit with an 8-iron.

Systems and methods for measuring the concentricity of golf balls using filter pairs to gather and analyze data on concentricity.

In a golf ball having a core, envelope layer, intermediate layer and cover, the core has a specific hardness profile, the resin materials making up either or both of the envelope layer and the intermediate layer contain a high-acid ionomer, and the Shore C hardness relationships among the core center, surface of the envelope-encased layer and surface of the intermediate layer-encased sphere satisfy the following conditions:
surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere,  (1)
surface hardness of intermediate layer-encased sphere−center hardness of core≥40.  (2)
This ball achieves a good distance on shots with utility and iron clubs, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

In a golf ball having a core, envelope layer, intermediate layer and cover, the core has a specific hardness profile, the resin materials making up either or both of the envelope layer and the intermediate layer contain a high-acid ionomer, and the Shore C hardness relationships among the core center, surface of the envelope-encased layer and surface of the intermediate layer-encased sphere satisfy the following conditions:

surface hardness of envelope layer-encased sphere<surface hardness of intermediate layer-encased sphere,  (1)

surface hardness of intermediate layer-encased sphere−center hardness of core≥40.  (2)

This ball achieves a good distance on shots with utility and iron clubs, is receptive to spin in the short game, and has a soft feel at impact on all shots, making it useful to amateur golfers.

An object of the present invention is to provide a golf ball having excellent approach spin performance under a dry condition and excellent approach spin performance under a condition that there is grass between the golf ball and the club face. 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 is composed of at least one layer, and an outermost paint film layer located at the outermost layer of the golf ball contains, as a base resin, a polyurethane obtained by a reaction between (A) a polyisocyanate composition and (B) a polyol composition, and the outermost paint film layer has a dynamic friction coefficient of from 0.75 to 1.5 measured with a dynamic friction tester under specific conditions.

A golf ball wherein a slide amount Ds is 1.05 mm or less and a post-slide contact time Tc is 600 μs or more in the case where a golf ball 140 is dropped freely from a height position of 3 m above and away from a collision surface 130a inclined 58 degrees with respect to a horizontal direction to collide with the collision surface, the slide amount Ds being a vertical displacement of the golf ball from when the golf ball starts sliding on the collision surface to when the golf ball stops sliding on the collision surface, and the post-slide contact time Tc being a period from when the golf ball stops sliding on the collision surface to when the golf ball leaves the collision surface.