abstract |
A golf ball includes a core having an outer surface, a geometric center, and a soft transition region adjacent to the outer surface. The soft transition region has a thickness of about 4 mm or less and includes about 2 to 10 percent of a trans-polybutadiene isomer. An outer cover layer has a hardness of about 50 Shore M or greater. The core outer surface hardness is greater than the hardness at the geometric center to define a positive hardness gradient of about 10 to 48 Shore C. The core has a secondary gradient quotient, GQ′, of 1.5 to 7.25, GQ′ being defined by the equation: n n n n n n n G n ′ n n + n T n n n 10 n × n COR n n n n n n where G′ is the positive hardness gradient in Shore C, T is the percent trans-polybutadiene isomer at the core outer surface, and COR is the coefficient of restitution of the core measured at an incoming velocity of 125 ft/s. |