Golf ball

DETAILED DESCRIPTION OF THE INVENTION This invention is particularly directed towards liquid filled center core shells for use in golf balls.
Specifically, the present invention is directed towards center core shell for a liquid filled center golf ball wherein the center core shell is formed from a thermoplastic material.
FIG.
1 provides an illustration of a cross sectional view of a thread wound golf ball according to one embodiment of the present invention.
As illustrated in FIG.
1, the golf ball includes a hollow, spherical center core shell 1 having its hollow interior filled with a liquid 2.
A thread rubber layer 3 is formed by winding rubber thread around the outer circumference of center core shell 1.
A cover 4 encases the thread rubber layer 3.
As used herein, the term thermoplastic means a linear polymer, either straight-chain or branch-chained macromolecules, that softens when exposed to heat and returns to its original condition when cooled to room temperature.
The polymer can be heated and cooled repeatedly, as long as it is not heated above its decomposition point.
This is because the polymer chains are held only by intermolecular forces that are relatively weak and permit easy movement and sliding of the chains under small temperature changes.
As used herein, the term polymer means any type of polymer including random polymers, block polymers, graft polymers, etc.
The efficacy of thermoplastic materials for use in forming liquid filled centers has heretofore been unknown.
Prior to the present invention, it was a general consensus in the golf ball art that a wound golf ball formed of a thermoplastic liquid filled sphere would exhibit inferior in-play characteristics such as decreased initial velocity as compared to conventional would golf balls formed using conventional liquid filled rubber "bags" or spheres.
However, by the present invention, it has been now discovered that certain thermoplastic materials are suitable to provide a liquid filled center shell for golf balls