Golf balls having low and high modulus core layers based on polyalkenamer rubber
View Patent ↗Golf balls golf balls containing a core having at least two layers made from a polyalkenamer rubber composition are provided. At least one layer is made from a relatively low modulus polyalkenamer rubber composition and at least one layer is made from a relatively high modulus polyalkenamer rubber composition. The rubber composition may further include other rubbers such as, for example, polybutadiene, polyisoprene, ethylene propylene rubber, ethylene propylene diene rubber, and styrene-butadiene rubber. The rubber composition helps improve resiliency of the core. In one version, a dual-core having an inner core and surrounding outer core layer is provided. In another version, the golf ball contains a three-piece core having an intermediate core layer made of polybutadiene rubber.
1. A golf ball, comprising:
a) an inner core layer formed from a first rubber composition, the first rubber composition comprising polyalkenamer rubber in an amount of 80 weight percent and polybutadiene rubber in amount of 20 weight percent, and having a modulus of 1,000 to 50,000 psi;
b) an outer core formed from a second rubber composition, the second rubber composition comprising polyalkenamer rubber in an amount of about 50 to about 95 weight percent and polybutadiene rubber, the second rubber composition having a modulus of 72,000 to 150,000 psi; the modulus of the first rubber composition being at least 25% less than the modulus of the second rubber composition; and
c) a cover.
2. The golf ball of claim 1 , wherein the first rubber composition comprises peroxide in an amount of 2.5 phr or greater based on weight of the polyalkenamer rubber.
3. The golf ball of claim 1 , wherein the core has an overall dual-core compression of 70 to 90.
4. The golf ball of claim 1 , wherein the inner core has a surface hardness of 30 to 87 Shore C.
5. The golf ball of claim 1 , Wherein the inner core has a surface hardness of 65 to 85 Shore C.
6. The golf ball of claim 1 , wherein the outer core layer has a surface hardness of 80 to 97 Shore C.
7. The golf ball of claim 1 , wherein the outer core layer has a surface hardness of 85 to 93 Shore C.
8. The golf ball of claim 1 , wherein the core has an overall dual-core diameter of 1.52 to 1.59 inches.
9. The golf bail of claim 1 , wherein the cover layer is formed from a composition selected from the group consisting of polyurethane; polyurea; or a hybrid, copolymer or blend of polyurethane and poly urea.
10. The golf ball of claim 1 , wherein the cover comprises an inner cover layer and outer cover layer.
11. The golf ball of claim 10 , wherein the hardness of the inner cover layer is greater than the hardness of the outer cover layer.