Abstract: In a golf ball comprising a solid or wound core and a cover, the solid core or a center of the wound core is prepared by molding and vulcanizing a rubber composition comprising 100 parts by weight of base rubber and 10-120 parts by weight of a weight adjuster having a mean particle size of 30-1,000 .mu.m and a specific gravity of 4-19.1. The solid core or center is improved in restitution and the ball will fly a longer distance.

Abstract: The present invention provides a multi-layer structure golf ball using a thread wound core, which has good shot feel and attains long flight distance. The golf ball comprises a thread wound core composed of a solid center and thread rubber layer on the center, and a cover covering the thread wound core, the cover having two layered structure comprising an inner layer cover and an outer layer cover, wherein the inner layer cover has a specific gravity of 1-1.8 and a thickness of 0.5-3 mm, the outer layer cover has a specific gravity of 0.9-1.1 and a thickness of 1-3 mm, the specific gravity of the inner layer cover is larger than that of the outer layer cover, the solid center has a diameter of from 28 to 35 mm, the thread rubber has a thickness of from 1 to 5.5 mm, and a ratio of (diameter (mm) of the solid center)/(amount of deformation (mm) formed by applying a load of from an initial load of 10 Kg to a final load of 130 Kg to the thread wound core) is from 5 to 15.

Abstract: A thread-wound golf ball manufactured by concurrently winding a pair of rubber threads spaced 1-7 mm apart from each other on a core to form a wound core, which is then enclosed with a covering material. The covering material reliably penetrates into a rubber thread layer, thereby achieving an improved bonding strength between the covering material and the rubber thread layer. Durability of the golf ball is enhanced and the time period required for winding threads is considerably reduced, resulting in an improved productivity.

Abstract: Disclosed is a thread wound golf ball comprising a center, a thread rubber layer formed by winding a thread rubber around the center and a cover formed on the thread rubber layer, wherein the thread rubber is obtained by cutting, into a suitable width, a rubber sheet for thread rubber which is obtained by vulcanizing a raw rubber sheet for thread rubber using a pressure rotary drum type continuous vulcanizing device.

Abstract: A two-layer cover structure having a hard inner layer and a soft outer layer, wherein the flight distance attained by using a driver or iron are increased and the ease of stopping the ball when making an approach shot is improved. The golf ball of the present invention comprises a core (1) and a cover formed on the core, wherein the cover has a two-layer cover structure of a hard inner cover layer (2) and a soft outer cover layer (3), and the inner cover layer (2) comprises a high-rigid polyamide resin present in an amount of not less than 5% by weight based on the total weight of the inner cover components.

Abstract: The present invention provides a thread wound golf ball which keeps good hit feeling inherently holding in thread wound golf balls and attains long flying distance which is equal to that attained by the two-piece solid golf ball. The thread wound golf ball comprises a center composed of a vulcanized molded article of a rubber composition, a thread rubber layer formed on said center and a cover covering on said thread rubber layer, wherein said center has a diameter of 30 to 35 mm and a strain amount formed between an initial loading of 10 kg and a final loading of 30 kg is 1.2 to 2.5 mm. The cover of the thread rubber layer has many dimples thereon and the product of total volume of the dimples and the diameter of the center is 8,500 to 11,000 mm.sup.3.mm.

Abstract: A thread wound golf ball is provided comprising a liquid center having a center bag filled with a liquid, thread rubber, and a cover. The center bag is filled with 8-12 cm.sup.3 of the liquid containing at least 55% by weight of water. The ball is improved in initial speed and travels an increased flying distance.

Abstract: A wound golf ball including a liquid center (4) in the form of a rubber bag (2) filled with a liquid (3), a thread rubber layer (5), and a cover (6). The filling liquid of the liquid center is a liquid having water-insoluble powder dispersed therein so as to have a specific gravity in the range of 1.08-1.70 and a viscosity in the range 1-6,000 centipoise at 23.degree. C. The water-insoluble fine particles are present in the range of 4-60% by weight of the liquid dispersion. By improving the filling liquid, the wound golf ball is increased in flying distance while maintaining its own controllability.

Abstract: The present invention provides a rubber composition having high impact residence, preferred processability and workability which may be used for the manufacture of one-piece solid golf ball, solid core of multi-layered solid golf ball, solid center of thread-wound golf ball, etc. The rubber composition is characterized by that a rubber component is made from a mixture of:(1) 60 to 95 wt % of a polybutadiene containing at least more than 40% of cis-1,4 bond and having a Mooney viscosity [ML.sub.1+4 (100.degree. C.)] of 50 to 70, obtained by using lanthanum rare earth-based catalyst, nickel-based catalyst or cobalt-based catalyst, or a mixture thereof with another polybutadiene obtained by using a catalyst other than the above mentioned one, and(2) 5 to 40 wt % of a polyisoprene containing at least more than 90% of cis-1,4 bond and a Mooney viscosity of 70 to 90.