Multi-layer core golf ball
Golf balls having a very high positive gradient multilayer core are provided. The multilayer core includes an outer core layer and a very soft, low compression inner core layer. The inner core layer is formed from an unfoamed composition and has a center hardness that is at least 40 Shore C points less than the outer surface hardness of the outer core layer.
1. A golf ball comprising a core and a cover, wherein the core comprises:
a solid inner core layer formed from an unfoamed composition and having a diameter of 1.10 inch or less and a center Shore C hardness (H center ) of 15 or less,
one or more optional intermediate core layers, and
an outer core layer having a thickness of 0.200 inches or greater and an outer surface Shore C hardness (H outer surface ) of 80 or greater,
wherein H outer surface >H center , and H outer surface −H center ≧70.
2. The golf ball of claim 1 , wherein the core has an overall compression of ≧70.
3. The golf ball of claim 1 , wherein the inner core layer composition is a thermoset composition consisting essentially of:
a base rubber;
from 0.1 phr to 2.0 phr of a peroxide;
optionally 5 phr or less of a metal oxide;
optionally 5 phr or less of a metal coagent;
optionally 5 phr or less of a metal carbonate; and
optionally one or more additional components selected from the group consisting of fillers, colorants, and antioxidants.
4. The golf ball of claim 1 , wherein the inner core layer composition is a thermoplastic.