# US 8,771,103 B2 · Multi-piece solid golf ball

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- Number: US 8,771,103 B2
- Document ID: US8771103B2
- Status: Granted
- Kind: B2
- Application number: 11/451,461
- Filed: 2006-06-13
- Published: 2007-12-13
- Granted: 2014-07-08
- Earliest claimed: 2006-06-13
- Assignees: Bridgestone Sports Co., Ltd.
- Applicants: Hideo Watanabe; Akira Kimura
- Inventors: Hideo Watanabe; Akira Kimura
- Web page: https://patentgrep.com/patent/US8771103B2

## CPC

- A63B 37/06: Elastic cores
- A63B 37/0003: {Golf balls}
- A63B 37/0006: {Arrangement or layout of dimples}
- A63B 37/00922: {whereby hardness of the cover is lower than hardness of the intermediate layers}
- A63B 37/0031: {Hardness}
- A63B 37/0033: {Thickness}
- A63B 37/0043: {Hardness}
- A63B 37/0045: {Thickness}
- A63B 37/0064: {Diameter}
- A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers}
- A63B 37/0083: {Weight; Mass}
- A63B 37/0095: {Scuff resistance}
- A63B 37/0096: {Spin rate}
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)

## Abstract

The invention provides a multi-piece solid golf ball having a core, an envelope layer which encloses the core, an intermediate layer which encloses the envelope layer, and a cover which encloses the intermediate layer and has formed on a surface thereof a plurality of dimples. The core is formed primarily of a rubber material, the envelope layer is formed primarily of a specific resin mixture, the intermediate layer is formed primarily of a resin material, and the cover is formed primarily of polyurethane. The intermediate layer and the cover have surface hardnesses (Durometer D hardness) which satisfy the relationship: intermediate layer surface hardness>cover surface hardness. The golf ball has an excellent flight performance and controllability that are acceptable to professionals and other skilled golfers, while also having an excellent durability to cracking on repeated impact and an excellent scuff resistance.

## Claims

### Claim 1

A multi-piece solid golf ball comprising a core, an envelope layer which encloses the core, an intermediate layer which encloses the envelope layer, and a cover which encloses the intermediate layer and has formed on a surface thereof a plurality of dimples, wherein the core is formed primarily of a rubber material; the envelope layer is formed primarily of a mixture comprising:
100 parts by weight of a resin component composed of, in admixture,
a base resin of (a) an olefin-unsaturated carboxylic acid binary random copolymer and/or a metal ion-neutralized product of an olefin-unsaturated carboxylic acid binary random copolymer mixed with (b) an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester ternary random copolymer and/or a metal ion-neutralized product of an olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester ternary random copolymer in a weight ratio between 100:0 and 0:100, and
(e) a non-ionomeric thermoplastic elastomer in a weight ratio between 100:0 and 50:50,
(c) 5 to 80 parts by weight of a fatty acid and/or fatty acid derivative having a molecular weight of 280 to 1500, and
(d) 0.1 to 10 parts by weight of a basic inorganic metal compound capable of neutralizing un-neutralized acid groups in the base resin and component (c);
the intermediate layer is formed primarily of a resin material; the cover is formed primarily of polyurethane; and the intermediate layer and the cover have surface hardnesses (Durometer D hardness) which satisfy the relationship
intermediate layer surface hardness>cover surface hardness;
the envelope layer and the intermediate layer have surface hardnesses which satisfy the relationship
envelope layer surface hardness<intermediate layer surface hardness; and
the envelope layer, the intermediate layer and the cover have thicknesses which satisfy the relationship
cover thickness<intermediate layer thickness<envelope layer thickness.

### Claim 2 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the core has a diameter of at least 31 mm.

### Claim 3 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the resin material of which the cover is formed as the outermost layer is a material composed primarily of a heated mixture of
(A) a thermoplastic polyurethane material, and
(B) an isocyanate mixture of (b-1) an isocyanate compound having at least two isocyanate groups as functional groups per molecule, dispersed in (b-2) a thermoplastic resin which is substantially non-reactive with isocyanate.

### Claim 4 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the surface of the envelope layer is softer than the surface of the intermediate layer by a difference in Durometer D hardness of at least 3 but not more than 20.

### Claim 5 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the surface hardness of the golf ball is smaller than the surface hardness of the intermediate layer by an amount within a Durometer D hardness range of 1 to 10.

### Claim 6 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the diameter of the dimples is set to at least about 2.5 mm but not more than about 6.5 mm.

### Claim 7 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the dimple coverage on the spherical surface of the golf ball, which is the sum of the individual dimple surface areas, each defined by the border of the flat plane circumscribed by the edge of the dimple, expressed as a ratio (SR) with respect to the spherical surface area of the ball were it to be free of dimples, is at least 60% but not more than 90%.

### Claim 8 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the value V0 obtained by dividing the spatial volume of each dimple below the flat plane circumscribed by the edge of that dimple by the volume of a cylinder whose base is the flat plane and whose height from the base to the maximum depth of the dimple is at least 0.35 but not more than 0.80.

### Claim 9 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the VR value, which is the sum of the volumes of individual dimples formed below flat planes circumscribed by the dimple edges, as a percentage of the volume of the ball sphere were it to have no dimples thereon, is at least 0.6% but not more than 1.0%.

### Claim 10 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the number of dimples arranged on the cover surface is at least 280 but not more than 360.

### Claim 11 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the envelope layer material has a hardness of 40 to 62 expressed as the Durometer D hardness.

### Claim 12 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the envelope layer has a surface hardness of 50 to 70 expressed as the Durometer D hardness.

### Claim 13 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the envelope layer has a thickness of 1.0 to 4.0 mm.

### Claim 14 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the intermediate layer material has a hardness of 50 to 70 expressed as the Durometer D hardness.

### Claim 15 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the intermediate layer has a surface hardness of 60 to 80 expressed as the Durometer D hardness.

### Claim 16 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the intermediate layer has a thickness of 0.7 to 2.0 mm.

### Claim 17 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the cover material has a hardness of 40 to 60 expressed as the Durometer D hardness.

### Claim 18 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the cover has a thickness of 0.3 to 1.5 mm.

### Claim 19 (depends on 1)

The multi-piece solid golf ball of claim 1, wherein the surface hardness of the ball, in terms of the Durometer D hardness, is at least 55 but not more than 70.