Golf ball

Abstract

The invention provides a golf ball having a core, at least one intermediate layer encasing the core, and a cover. The intermediate layer is formed primarily of a specific ionomer resin composition that is highly neutralized. The cover is formed by injection molding a single resin blend composed primarily of a thermoplastic polyurethane and (g) a polyisocyanate compound in at least some portion of which all the isocyanate groups on the molecule are present in an unreacted state. The golf ball of the invention has a low spin rate on shots with a driver, enabling it to travel a good distance, and achieves a sufficient spin rate on shots with a short iron such as a wedge. The ball also has an excellent scuff resistance.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a golf ball which achieves a good distance on shots with a driver and has good spin properties on shots with an iron, and which moreover has an excellent scuff resistance and a good durability.[0002]Most golf balls currently in use are generally manufactured by using a process such as injection molding or compression molding to encase the periphery of a solid core made primarily of a rubber such as diene rubber with a material composed primarily of, for example, urethane resin or ionomer resin.[0003]The major performance attributes required of golf balls include distance, controllability, durability and feel on impact; balls having the highest levels of such attributes are constantly being sought. In this context, there has emerged among recent golf balls a succession of balls with multilayer structures—typically three-piece balls. Providing a golf ball with a multilayer structure makes it possible to combine many mat...

AI Technical Summary

Benefits of technology

[0008]It is therefore an object of the present invention to provide a golf ball which achieves a good distance by suitably reducing the spin rate on shots with a driver, which achieves a suitable spin rate on shots with a short iron, and which has an excellent scuff resistance and a good durability.

Problems solved by technology

Although the distance in such a case can be increased, when the ball is hit with a short iron such as a wedge, sufficient spin is not achieved, resulting in a poor controllability and a diminished feel.

Yet, at the same time, making the ball softer lowers the rebound and also increases the spin rate on shots with a driver, making it difficult to achieve an increased distance.

A cover made of an ionomer resin that does not readily crack and is somewhat soft is commonly used in such soft (low hardness) balls, but the resulting balls tend to have a poor scuff resistance.

Sometimes the cover is made instead of a thermoplastic polyurethane resin, although prior-art covers made of thermoplastic polyurethane resins also have a poor scuff resistance.

Although forming an intermediate layer of a highly neutralized ionomer resin composition in which the degree of neutralization of the ionomer resin has been increased through the addition of a basic inorganic metal compound is effective for enhancing rebound and lowering the spin rate, the resulting ball often has a poor durability.

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