Abstract: The present invention provides a hollow golf ball having good shot feel at the time of hitting by making impact force small, while keeping excellent flight performance. Improved shot feel at the time of hitting by improving an impact absorption, while keeping excellent flight performance. The present invention relates to a hollow golf ball comprising: a hollow core composed of a hollow portion and one or more hollow core outer layers formed from a core composition comprising rubber component, resin component or the mixture thereof, and a cover formed on the hollow core, wherein, when a secondary natural frequency of the hollow golf ball is expressed as X and a deformation amount, when applying from an initial load of 10 kgf to a final load of 130 kgf on the hollow golf ball, is expressed as Y, a difference of X−Y is within the range of 0.1 to 1.5.

Abstract: An earth-friendly tire using raw materials derived from non-petroleum resources instead of all or part of raw materials derived from petroleum resources currently used for tires.The tire is prepared by using a natural rubber instead of a synthetic rubber; an inorganic filler and/or a biofiller instead of carbon black; vegetable oil instead of petroleum oil; and natural fiber instead of synthetic fiber so that the tire comprises a non-petroleum raw material in an amount of at least 75% by weight based on the total weight of the tire.

Abstract: A rubber composition for tire and a pneumatic tire in which the rubber composition is used improve steering performance on snowy and icy roads as well as traction performance in the forward and backward directions while reducing the recycling and manufacturing cost. The rubber composition for tire contains from 0.5 to 12 parts by weight of paper relative to 100 parts by weight of a rubber component, and preferably further contains from 5 to 100 parts by weight of silica and from 2 to 15 parts by weight of short fiber relative to 100 parts by weight of the rubber component. The paper is newspaper waste. From 10 to 100 parts by weight of carbon black may further be contained relative to 100 parts by weight of the rubber component.

Abstract: A hollow golf ball comprising a hollow core and a cover layer that possesses good shot feel, an increased moment of inertia, and a high launch angle at the time of hitting. Immediately after impact, the hollow golf ball has a small spin amount. The specific hollow core reduces the rate of spin dumping between the ascending and descending of the ball, which results in increased flight distance. The hollow golf ball has a hollow core and a cover layer formed on the core, wherein the hollow core is composed of a hollow portion having a diameter of 5 to 30 mm and a core outer layer portion surrounding said hollow portion.

Abstract: A hollow golf ball having good shot feel at the time of hitting, while maintaining excellent flight performance, wherein the hollow golf ball has a hollow core having a hollow portion and one or more hollow core outer layers formed thereon, the hollow core outer layers having a core composition containing rubber, a resin or a mixture thereof, and a cover formed on the hollow core, and wherein the hollow portion has a diameter of 5 to 25 mm, the hollow core outer layer has a surface hardness of 71 to 91 in JIS-C hardness and a deformation amount of 2.0 to 3.5 mm when applying from an initial load of 10 kgf to a final load of 130 kgf on the core.

Abstract: A method of producing a hollow golf ball having excellent durability, which comprises a hollow portion with perfect spherical shape. The method of making a hollow golf ball having a hollow core composed of a hollow center having a hollow portion and optionally one or more intermediate core layers formed on the hollow center, and a cover formed on the hollow core, includes the steps of (a) preparing a rubber composition for the hollow center, (b) molding the rubber composition for the hollow center into a vulcanized semi-spherical half-shell, and (c) bonding the two vulcanized semi-spherical half-shells by placing an unvulcanized adhesive rubber composition between bonding surfaces of the two vulcanized semi-spherical half-shells, and vulcanizing it in a mold to form the hollow center, wherein the unvulcanized rubber composition has a t.sub.90 time of 5 to 20 minutes, the t.sub.

Abstract: The present invention provides a method for the production of a hollow golf ball, which has a perfect spherical hollow portion and possesses excellent durability and good shot feel at the time of hitting, without adversely affecting a good rebound performance. The present invention provides a method for producing a hollow golf ball comprising a hollow core (5) having a hollow center (2) and a hollow portion (1) and, optionally, at least one intermediate core layer (3) formed on the hollow center (2), and a cover (4) formed on the hollow core (5), wherein the step of producing the hollow center (2) comprises:(i) preparing a rubber composition for hollow center;(ii) forming a bowl-shaped half-shell from the rubber composition for the hollow center and vulcanizing only the inside of the half-shell; and(iii) bonding two of the half-shells together to form a complete sphere body which is then vulcanized to obtain the hollow center (2).

Abstract: The present invention provides a hollow golf ball having a spherical cavity in the center, which exhibits excellent durability and less impact strength to result in excellent shot feel without degrading flight performance, and the production of the same. The hollow golf ball includes: (a) hollow center formed from a material selected from the group consisting of rubber, thermoplastic resin and a mixture thereof, the hollow center having a hollow portion with a diameter of 5 to 30 mm; (b) at least one core rubber layer, formed on said hollow center, the core rubber layer being obtained by vulcanizing a rubber composition which comprises a base rubber, a metal salt of an unsaturated carboxylic acid, an organic peroxide and filler; and (c) a cover formed on said core rubber layer.