A golf ball comprising a center comprising a polybutadiene having a molecular weight of greater than 200,000 and a resilience index of at least about 40; and a cover layer comprising a polyurethane composition formed from a prepolymer having no greater than 7.5 percent by weight unreacted isocyanate groups.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 10/256,011, filed Sep. 27, 2002, now U.S. Pat. No. 6,818,705, which is a continuation of U.S. patent application Ser. No. 09/721,740, filed Nov. 27, 2000, now U.S. Pat. No. 6,486,261, which is a continuation-in-part of U.S. patent application Ser. No. 09/461,736, filed Dec. 16, 1999, now U.S. Pat. No. 6,465,578, which claims the benefit of U.S. Patent Provisional Application No. 60/113,949, filed Dec. 24, 1998, and a continuation-in-part of U.S. patent application Ser. No. 09/311,591, filed May 14, 1999, now U.S. Pat. No. 6,210,294, and also a continuation-in-part of U.S. patent application Ser. No. 09/274,015, filed Mar. 22, 1999.
A golf ball comprising a center comprising a polybutadiene having a molecular weight of greater than 200,000 and a resilience index of at least about 40; and a cover layer comprising a polyurethane composition formed from a prepolymer having no greater than 7.5 percent by weight unreacted isocyanate groups.
Golf balls including centers formed from polybutadiene reaction products having a percent change in dynamic stiffness from 0.degree. C. to -50.degree. C. of less than 130 percent where the reaction products include a resilient polymer component, a crosslinking material, a cis-to-trans catalyst, and a free radical source. The golf balls may be formed with polyurethane covers, covers formed from castable reactive liquid materials, among other materials. The golf balls may also include an intermediate layer.
