The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 2000
Filed:
Jul. 16, 1999
Sumitomo Rubber Industries, Ltd., Hyogo-ken, JP;
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.90 time being a time for reaching 90% of a maximum torque, when the unvulcanized rubber composition is formed into a circular sample having a diameter of 43 mm and a thickness of 3 mm and then a torque is measured using a curastometer at a test temperature that is the same as a vulcanizing temperature.