Golf Ball Core Rubber Composition Hardness Gradient

The patent applies local quality by creating different crosslinking densities at different locations within the single-layer core. The core surface has high crosslinking density (high hardness) while the center has low crosslinking density (low hardness), achieving the desired hardness gradient without requiring multiple layers. This is accomplished through controlled peroxide decomposition and crosslinking reactions that proceed differently at the surface versus the center during vulcanization.

The patent resolves this contradiction by creating a spatial gradient in hardness: the core surface has high hardness (high crosslinking density) to reduce spin rate on full shots, while the core center maintains low hardness (low crosslinking density) to preserve good feel on impact. This local differentiation of properties allows both requirements to be satisfied simultaneously within a single-layer core structure.

The patent goes beyond simply adjusting the type and amount of co-crosslinking agents. Instead, it changes the fundamental parameter of crosslinking density distribution in space by controlling peroxide decomposition and crosslinking reactions. This creates a gradient in crosslinking density from surface to center, which simultaneously optimizes both core hardness and spin properties, overcoming the limitations of conventional uniform crosslinking approaches.