abstract |
A golf ball including a core having an inner core having an outer surface and a geometric center; and an outer core layer. The outer core layer has an outer surface and includes a soft transition region. An outer cover layer is formed over the core. The soft transition region has a thickness of up to 4 mm, has about 5 to 15 percent trans-polybutadiene isomer, and has a negative hardness gradient of up to about 10 Shore C. The core has an overall positive hardness gradient of about 5 Shore C to 15 Shore C and has a gradient quotient, GQ, defined by the equation: n n n n n 1 n ≤ n n n G n + n T n n n 10 n × n COR n n n ≤ n 4 n n n n n where G is the overall positive hardness gradient in Shore C, T is the percent of trans-polybutadiene isomer at the core outer surface, and COR is the coefficient of restitution measured at an incoming velocity of 125 ft/s. |