Low compression golf ball

Abstract

This invention relates to the use of chemical compounds to trap carbon-centered radicals during the golf ball curing process. The intended end result is a golf ball that has lower compression due to a decrease in crosslink density while retaining sufficient crosslink density to impart durability to the golf ball and either maintain or increase the resiliency of the golf ball. The subject invention more specifically discloses a golf ball which is comprised of a solid core and a resin cover wherein the core is produced by curing a composition comprising an elastomeric polymer, a free radical initiator, a radical crosslinking agent, and at least one carbon-centered radical trap, wherein the carbon-centered radical trap is free of sulfur, and wherein the carbon-centered radical trap is not a stable free radical. The present invention further discloses a process for manufacturing a golf ball core which comprises (1) blending a mixture of an elastomeric polymer, a free radical initiator, a radical crosslinking agent, and at least one carbon-centered radical trap to produce a golf ball core composition, wherein the carbon-centered radical trap is free of sulfur, and wherein the carbon-centered radical trap is not a stable free radical, (2) compressing the golf ball core composition into an essentially spherical shape to produce an uncured golf ball core and (3) heating the uncured golf ball cure at an elevated temperature to produce a cured golf ball core.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60 / 616,110, filed on Oct. 5, 2004, and incorporates herein by reference the teaching thereof in their entirety.FIELD OF THE INVENTION [0002] This invention relates to the use of chemical compounds to trap carbon-centered radicals during the golf ball curing process. The intended end result is a golf ball that has lower compression due to a decrease in crosslink density while retaining sufficient crosslink density to impart durability to the golf ball and either maintain or increase the resiliency of the golf ball. BACKGROUND OF THE INVENTION [0003] Golfers desire golf balls with high resiliency, which translates into improved flight distance. While desiring a long flight distance, golfers are also accustomed to a particular range of feel and sound from the golf ball. In general, an increase in resiliency can be obtained by manipulating the golf ball formulation. The problem with this approach ...

AI Technical Summary

Benefits of technology

[0024] The invention relates to the use of a carbon-centered radical trap in a golf ball formulation which includes an amount of polybutadiene, a free radical source, and a crosslinking coagent, such that the reaction product of the formulation has a lower extent of cure than would be present without said agent to trap carbon-centered radicals. This reduction in cure translates into reduced compression and a softer feel from the finished ball. Concurrently, the resiliency and flight distance of the compound may be increased or decreased by the presence of the carbon-centered radical trap.

Problems solved by technology

The problem with this approach however, is that augmentations to the formulation that would result in improved resiliency typically increase the rigidity of the golf ball.

Wound balls generally are more difficult and expensive to manufacture than solid golf balls.

One-piece balls are the simplest and least expensive to manufacture but do not offer the desired playing characteristics.

However, it was also reported that the curing process generated an exotherm during the vulcanization step.

The difficulty lies in the fact that to reach a necessary degree of crosslinking there needs to be a sufficient amount of polymerizable coagent as reported in U.S. Pat. No. 4,056,269 and U.S. Pat. No. 4,264,075.

However, it was also reported that the exotherm generated during the curing step made the molding process more difficult.

If a golf ball core is formulated with a lower level of polymerizable coagent, the resiliency and durability of the ball are compromised.

However, the degree of exotherm found during the cure is less and the time for complete conversion of the peroxide is conversely much longer.

The ability to control the exotherm by cooling is limited by the dimensions of the ball, which offer very little surface area to volume.