Negative Hardness Gradient Core Produced from a Low, Temperature-Based Cure Cycle Index

摘要

A method of making a golf ball comprising the steps of providing a preform comprising an uncured polybutadiene composition; curing the preform for a first isothermal step at a cure cycle index of 200 or less to form a crosslinked golf ball core having an outer diameter of 1.0 inches or greater, and an outer surface having a first hardness and a geometric center having a second hardness equal to or greater than the first to define a zero hardness gradient or a negative hardness gradient, wherein the cure cycle index has a formula ${\mathrm{CCI}}_{\mathrm{time}}=\sum _{n=1}^nt_n\mathrm{Log}T_n$ where t=time in min, T=temperature in ° C., and n=the number of the isothermal step; and forming at least one cover layer about the core to form the golf ball.