Golf ball incorporating tie layer between differing adjacent layers

Abstract

A golf ball having improved adhesion comprising: a core; a first layer surrounding the core; a tie layer surrounding at least a portion of an outer surface of the first layer and consisting of a mixture of a polyfunctional aziridine compound and a solvent; and a second layer that is different than the first layer formed about the tie layer. The first layer may consist of a non-urethane composition whereas the second layer consists of at least one urethane composition. The first layer may comprise a non-urethane composition whereas the second layer consists of at least one urethane composition. The first layer may consist of a non-urethane composition while the second layer comprises a urethane composition. The first layer may comprise an ionomer for example. The solvent may be aprotic. Alternatively, the solvent may be protic.

Description

FIELD OF THE INVENTION[0001]The present invention relates to durable golf balls possessing excellent adhesive strength between differing adjacent layers (i.e., layers having different chemical and / or physical properties).BACKGROUND OF THE INVENTION[0002]Golf balls are made in a variety of constructions and compositions. In this regard, each of the golf ball core, intermediate layer, and cover may be single layered or comprise multiple layers. Examples of golf ball materials range from balata to polybutadiene, ionomer resins, polyurethanes, and / or polyureas. Typically, outer layers are formed about the spherical outer surface of an inner golf ball component via compression molding, casting, or injection molding.[0003]Golf ball manufacturers continuously experiment with golf ball constructions and material formulations in order to target and improve aerodynamic and / or inertial properties and achieve desired feel without sacrificing durability. In this regard, the adhesion that exists ...

AI Technical Summary

Benefits of technology

The invention is a golf ball with improved adhesion between layers. It includes a core, a first layer surrounding the core, and a tie layer surrounding at least a portion of the outer surface of the first layer. The tie layer is made of a mixture of a polyfunctional aziridine compound and a solvent. The first layer can be made of a non-urethane composition and the second layer can be made of at least one urethane composition. The core can be made of polybutadiene. The mixture of the polyfunctional aziridine compound and solvent can be in a wt % ratio of from about 1:199 to about 1:199. The tie layer can surround the entire outer surface of the first layer or a portion of it. The second layer can be made of at least one urethane composition. The invention also includes a method of making the golf ball and a method of exposing the outer surface to the tie layer composition. The technical effects of the invention include improved adhesion between layers, improved durability, and improved performance.

Problems solved by technology

Without a satisfactory amount of adhesion between these layers, both the impact durability as well as the shear resistance of the cover can be deemed as unacceptable.

This issue sometimes arises, for example, in preparing solid multilayer balls when materials of an outer layer do not necessarily bond well with the materials used in the inner layers, especially when two adjacent golf ball layers are formed from different compositions—e.g., an ionomeric casing / intermediate layer surrounded by a polyurethane cover layer.

In such constructions, bond strength or “adhesive strength” between the two differing adjacent layers may be insufficient.

Poor bond or adhesive strength can result in layer separation or “delamination” when the golf ball is struck by a club.

Delamination detrimentally affects not only the appearance of the golf ball but playability as well.

A significant limitation with techniques such as the corona and plasma treatments, however, is that a newly reactive treated surface rapidly reverts back to its normal state when re-exposed to air if the outer layer is not assembled about the treated surface immediately following treatment.