Golf ball
AssigneeBridgestone Sports Co., Ltd.
InventorJun Shindo
Life of this patent
Estimating the term…
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 α,β-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.
Claims13
A golf ball comprising a core and a cover of one or more layer, wherein the core is a product molded under heat from a rubber composition which includes:
- (a) a base rubber,
- (b) zinc diacrylate (ZDA) as a co-crosslinking agent,
- (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 70 or more;
- the core includes grafted polymers of BR-ZDA in which ZDA nanoparticles agglomerate to become secondary particles and further the secondary particles are connected mutually such that a network structure is formed;
- the core has a deformation when compressed under a load of 1,275 N (130 kgf) from an initial load state of 98 N (10 kgf) of not more than 3.5 mm;
- and the core has a center and a surface with a hardness difference therebetween on the JIS-C hardness scale of 16 or more.
Dependencies are inferred from the claim text.