US-20260124503-A1 - MULTI-LAYER GOLF BALLS WITH INCREASED INTERLAYER ADHESION

US20260124503A1US 20260124503 A1US20260124503 A1US 20260124503A1US-20260124503-A1

Abstract

Casing compositions including carboxylic acid groups, cover compositions including an adhesion promoter with functional groups that crosslink with carboxylic acid groups, and golf balls made from such compositions that have crosslinks between functional groups of the cover compositions and the carboxylic acid groups. 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. Additionally, methods of crosslinking casing and cover layers made from such casing and cover compositions to increase interlayer adhesion are disclosed.

Inventors

Michael Michalewich
Shawn Ricci

Assignees

ACUSHNET COMPANY

Dates

Publication Date: 20260507
Application Date: 20251229

Claims (20)

1 . A golf ball, comprising: a core; a casing layer disposed on the core, wherein the casing layer has a moisture content in a first amount and comprises carboxylic acid groups and; and a cover disposed on the casing layer, wherein the cover comprises an adhesion promoter present in a second amount and comprising functional groups that crosslink with the carboxylic acid groups in the casing layer to form one or more of the following linkage:
2 . The golf ball of claim 1 , wherein the cover further comprises a base polymer selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof.
3 . The golf ball of claim 1 , wherein the first amount is about 0.1 percent to about 5 percent by weight.
4 . The golf ball of claim 3 , wherein the first amount is about 0.1 percent to about 1.5 percent by weight.
5 . The golf ball of claim 1 , wherein the second amount is about 0.1 percent to about 5 percent by weight.
6 . The golf ball of claim 5 , wherein the second amount is less than the first amount.
7 . The golf ball of claim 1 , wherein the adhesion promoter comprises an organic silane.
8 . A golf ball, comprising: a center; an outer core layer disposed on the center; a casing layer disposed on the outer core layer, wherein the casing layer comprises carboxyl groups; and a cover layer disposed about the casing layer and formed from a cover composition comprising an adhesion promoter with at least one functional group, wherein the casing layer and cover layer are bonded by crosslinks between the at least one functional group in the cover layer and the carboxyl groups in the casing layer.
9 . The golf ball of claim 8 , wherein at least one of the center and outer core layer comprises a rubber formulation including a base rubber, and wherein the base rubber is a polybutadiene rubber, butyl rubber, or a blend thereof.
10 . The golf ball of claim 8 , wherein the crosslinks comprises the following linkage:
11 . The golf ball of claim 8 , wherein the casing layer has a moisture content, wherein the cover composition comprises a second amount of adhesion promoter by weight of the cover composition, and wherein the second amount is less than the moisture content.
12 . The golf ball of claim 11 , wherein the moisture content is about 0.1 percent to about 5 percent by weight.
13 . The golf ball of claim 12 , wherein the second amount is about 0.1 percent to about 5 percent by weight of the cover composition.
14 . The golf ball of claim 8 , wherein the casing layer comprises an ionomer.
15 . The golf ball of claim 14 , wherein the cover composition further comprises a base polymer selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof.
16 . A golf ball, comprising: a core; a casing layer disposed on the core, wherein the casing layer comprises carboxyl groups; and a cover layer disposed about the casing layer and formed from a cover composition comprising an adhesion promoter with at least one functional group that crosslink with the carboxyl groups to form one or more of the following linkage:
17 . The golf ball of claim 16 , wherein the cover composition further comprises a base polymer selected from the group consisting of polyurethanes, polyureas, and hybrids, copolymers, and blends thereof.
18 . The golf ball of claim 16 , wherein the adhesion promoter is present in the cover composition in an amount of about 0.1 percent to about 5 percent by weight.
19 . The golf ball of claim 18 , wherein the casing layer comprises ionomer and has a moisture content.
20 . The golf ball of claim 19 , wherein the moisture content is higher than the amount of adhesion promoter in the cover composition.

Description

FIELD OF THE INVENTION The present disclosure relates generally to compositions for use in golf ball components that facilitate crosslinks between the components and methods of forming golf balls made from such components. The compositions and methods of the present disclosure result in golf ball components with improved adhesion strength therebetween. In addition, the compositions and methods 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 golf ball when such components are used in a golf ball. In addition, the present disclosure provides methods of making golf balls using such compositions and components made from such compositions to produce golf balls having increased shear durability and increased adhesion strength between layers. 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 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. Adhesion promoters are likewise usually 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 layer disposed on the core, the casing layer formed from a casing composition including carboxyl groups; and a cover disposed on the casing layer, the cover formed from a cover composition including a base polymer and adhesion promoter, wherein the cover composition i