US-20260124504-A1 - MULTI-LAYER GOLF BALLS WITH IN-SITU ADHESION PROMOTER

US20260124504A1US 20260124504 A1US20260124504 A1US 20260124504A1US-20260124504-A1

Abstract

Casing compositions including carboxyl groups, cover compositions including nucleophile groups and an adhesion promoter capable of crosslinking carboxyl and nucleophile groups, and golf balls made from such compositions that have crosslinks between carboxyl groups in the casing composition and nucleophile groups in the cover composition. The nucleophile groups may be hydroxyl groups, amino groups, or other types of nucleophile groups. The adhesion promoter may be a polyaziridine. An acid catalyst may be used to facilitate the reaction between the nucleophile groups in the cover composition and the adhesion promoter. The type and concentration of the components in the casing and cover compositions, including the adhesion promoter, affect the adhesion between golf balls having components made from such compositions and, thus, can be used to produce a golf ball having increased durability.

Inventors

Michael Michalewich
Shawn Ricci

Assignees

ACUSHNET COMPANY

Dates

Publication Date: 20260507
Application Date: 20260105

Claims (20)

1 . A golf ball, comprising: a subassembly comprising at least one layer, wherein the at least one layer is formed from a composition comprising carboxyl groups; an outer layer disposed on the subassembly and formed from a composition comprising nucleophile groups; and crosslinks between the carboxyl groups and the nucleophile groups.
2 . The golf ball of claim 1 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1, R2, and R3 are carbon chains.
3 . The golf ball of claim 1 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1, R2, and R3 are carbon chains.
4 . The golf ball of claim 1 , wherein the composition comprises an adhesion promoter.
5 . The golf ball of claim 4 , wherein the composition further comprises a catalyst.
6 . The golf ball of claim 5 , wherein the catalyst is an acid catalyst.
7 . A golf ball, comprising: a core; a casing layer disposed on the core, wherein the casing layer is formed from a casing composition comprising carboxyl groups; a cover disposed on the casing layer, wherein the cover layer is formed from a cover composition comprising nucleophile groups; and crosslinks between the carboxyl groups and the nucleophile groups.
8 . The golf ball of claim 7 , wherein the cover composition further comprises an adhesion promoter.
9 . The golf ball of claim 8 , wherein the adhesion promoter comprises a polyaziridine.
10 . The golf ball of claim 8 , wherein the adhesion promoter is included in the cover composition in an amount of about 0.01 percent to about 5.0 percent by weight.
11 . The golf ball of claim 8 , wherein the cover composition further comprises an acid catalyst.
12 . The golf ball of claim 7 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1, R2, and R3 are carbon chains.
13 . The golf ball of claim 7 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1, R2, and R3 are carbon chains.
14 . The golf ball of claim 8 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1 is a carbon chain in the adhesion promoter, R2 is a carbon chain in the cover layer, and R3 is a carbon chain in the casing layer.
15 . The golf ball of claim 8 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1 is a carbon chain in the adhesion promoter, R2 is a carbon chain in the cover layer, and R3 is a carbon chain in the casing layer.
16 . A golf ball, comprising: a subassembly comprising at least one layer, wherein the at least one layer is formed from a composition comprising carboxyl groups; an outer layer disposed on the subassembly and formed from a composition comprising an adhesion promoter and nucleophile groups; and crosslinks between the carboxyl groups and the nucleophile groups.
17 . The golf ball of claim 16 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1, R2, and R3 are carbon chains.
18 . The golf ball of claim 17 , and wherein R1 is a carbon chain in the adhesion promoter, R2 is a carbon chain in the cover layer, and R3 is a carbon chain in the casing layer.
19 . The golf ball of claim 16 , wherein the crosslinks comprise one or more of the following linkage: and wherein R1, R2, and R3 are carbon chains.
20 . The golf ball of claim 19 , and wherein R1 is a carbon chain in the adhesion promoter, R2 is a carbon chain in the cover layer, and R3 is a carbon chain in the casing layer.

Description

FIELD OF THE INVENTION The present disclosure relates generally to compositions for use in golf ball components that facilitate crosslinks between the components. The compositions of the present disclosure result in golf ball components with improved adhesion strength therebetween. In addition, the compositions of the present disclosure result in golf balls with better shear durability (as compared to conventional golf balls). More particularly, the present disclosure provides compositions and golf ball components made from such compositions that provide increased shear durability and increased adhesion strength between two or more layers of a golf ball when such components are used in a golf ball. BACKGROUND OF THE INVENTION The performance and/or durability of a golf ball is affected by a variety of factors including the materials, weight, size, dimple pattern, and external shape of the golf ball. As a result, golf ball manufacturers are constantly improving or tweaking the materials and construction of a ball in an effort to make incremental gains in performance without sacrificing durability. In this aspect, one issue with the multi-piece golf balls commonly used in modern play is the lack of adhesion between layers of the golf ball. Adhesion strength is a direct measure of the adhesion between two or more layers of a golf ball. The adhesion strength between two layers can be measured as the force required to separate the two layers. Low adhesion strength between layers of a golf ball may result in the golf ball having low shear durability. Golf balls having a low shear durability may delaminate more frequently when exposed to a shear force. Delamination is the decoupling of an outer layer of the golf ball, such as the cover of the golf ball, from an adjacent inner layer, such as a casing layer. Delamination commonly occurs when a golf ball is struck with a high-angle club, such as a wedge, that imposes a strong shear force on the golf ball. As a result of the shear force, the outer and inner layers may move in different directions or at different speeds and decouple from each other. Delamination may be visibly apparent as “bubbling” or air pockets between layers or as cutting in the cover of the golf ball. Delamination detrimentally affects not only the appearance of the golf ball but the performance as well. Modern multi-piece, solid golf balls often include a core, a casing layer disposed around the core, and a cover layer disposed around the casing layer. Casing layers and cover layers may be made of a variety of materials including ethylene acid copolymer ionomers, polyamides, polyesters, polyurethanes, and polyureas. In particular, cover layers are commonly cast from polyurethane. For example, popular three-piece golf balls may include a rubber core surrounded by an ionomer-based casing layer and a urethane-based cover layer. Currently, several different types of adhesion-promoting pre-treatment processes exist for addressing cut and shear issues caused by lack of adhesion between casing and cover layers. Examples of pretreatments include surface roughening; surface energy modifications such as corona, plasma, and flame treatments; adhesives; adhesion promoters; and combinations thereof. Adhesives are typically applied via spray or dip and usually require a drying and post-cure step. Certain adhesion promoters may be applied by dip or spray, followed by rinsing and drying steps. For golf balls having a cast urethane cover disposed on a casing layer, the casing layer must be treated with primer to increase adhesion between the casing layer and cover and decrease the likelihood of delamination. These adhesion-promoting processes increase the adhesion strength between layers and the overall durability of the golf ball but require expensive materials and additional steps in the manufacturing process, which increases manufacturing time and cost. Thus, it would be advantageous to have compositions for use in the casing and cover layers of golf balls that improve the durability of the golf ball while still providing desirable playing properties and without the need for additional materials or manufacturing steps. The present invention provides such compositions and golf balls including components made with such compositions. SUMMARY OF THE INVENTION The present invention relates to a golf ball including: a core; a casing layers disposed on the core, the casing layer formed from a composition including carboxyl groups; a cover disposed on the casing layer and formed from a cover composition including nucleophile groups and a polyaziridine adhesion promoter; and crosslinks between the carboxyl groups of the casing layer and the nucleophile groups of the cover layer. In some embodiments, the nucleophile groups include hydroxyl groups, and the crosslinks may include one or more of the following linkage: wherein R1 is a carbon chain in the adhesion promoter, R2 is a carbon chain in the cover layer, and R3 is