# US 7,077,764 B2 · Golf ball

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- Number: US 7,077,764 B2
- Document ID: US7077764B2
- Status: Granted
- Kind: B2
- Application number: 10/823,799
- Filed: 2004-04-14
- Published: 2005-10-20
- Granted: 2006-07-18
- Earliest claimed: 2004-04-14
- Assignees: Bridgestone Sports Co., Ltd.
- Inventors: Hideo Watanabe; Hiroyuki Nagasawa
- Web page: https://patentgrep.com/patent/US7077764B2

## CPC

- A63B 37/0003: {Golf balls}
- A63B 37/00621: {Centre hardness}
- A63B 37/00622: {Surface hardness}
- A63B 37/0033: {Thickness}
- A63B 37/0036: {Melt flow rate [MFR]}
- A63B 37/0051: {Materials other than polybutadienes; Constructional details}
- A63B 37/0054: {Substantially rigid, e.g. metal}
- A63B 37/0063: {Hardness gradient}
- A63B 37/0065: {Deflection or compression}
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)

## Abstract

A golf ball comprising a core and a cover formed of a cover resin composition is characterized in that the core has a hardness corresponding to a compressive deflection amount of at least 3.5 mm when the load applied thereto is increased from an initial load of 10 kgf to a final load of 130 kgf, the cover resin composition has a melt flow rate of at least 3 as measured according to JIS K7210, and the cover has a gage of up to 1.7 mm. The golf ball has a soft feel, offers superior flight performance to even those golf players with a low head speed of 35 m/s or less, and is improved in durability to repeated impact and moldability.

## Claims

### Claim 1

A golf ball comprising a core and a cover formed of a cover resin composition, wherein said core has a hardness corresponding to a compressive deflection amount of at least 3.5 mm when the load applied thereto is increased from an initial load of 10 kgf to a final load of 130 kgf, said cover resin composition has a melt flow rate of at least 3 as measured according to JIS K7210, and said cover has a gage of up to 1.7 mm, and
wherein said cover resin composition comprises (a) at least one component selected from the group consisting of olefin-unsaturated carboxylic acid copolymers, olefin-unsaturated carboxylic acid-unsaturated carboxylic acid ester copolymers, and metal ion-neutralized products of these copolymers and (b) a binary copolymer consisting of polyolefin and polyamide components in admixture as a resin component.

### Claim 2 (depends on 1)

The golf ball of claim 1, wherein said core has a hardness at its center of 28 to 40 in Shore D hardness and a hardness at its surface of 35 to 52 in Shore D hardness, and the difference in hardness between the core surface and the core center is 3 to 20.

### Claim 3 (depends on 1)

The golf ball of claim 1, wherein said cover resin composition has organic short fibers dispersed and incorporated therein.

### Claim 4 (depends on 1)

The golf ball of claim 1, wherein the polyamide in component (b) is in fiber form.

### Claim 5 (depends on 1)

The golf ball of claim 1, wherein a weight ratio of (a)/(b) is between 100/0.1 and 100/50.

### Claim 6 (depends on 1)

The golf ball of claim 1, wherein in component (b), a weight ratio of polyolefinlpolyamide components is between 25/75 and 95/5.

### Claim 7

A golf ball comprising a core and a cover formed of a cover resin composition, wherein said core is formed of a rubber composition containing polybutadiene synthesized with a rare-earth catalyst as base rubber, and the core has a hardness corresponding to a compressive deflection amount of at least 3.5 mm when the load applied thereto is increased from an initial load of 10 kgf to a final load of 130 kgf, said cover resin composition has a melt flow rate of at least 3 as measured according to JIS K7210, and said cover has a gage of up to 1.7 mm.

### Claim 8 (depends on 7)

The golf ball of claim 7, wherein said cover has a Shore D hardness of 59 to 61.

### Claim 9 (depends on 7)

The golf ball of claim 7, wherein said core contains an organosulfur compound or organosulfur compounds.

### Claim 10 (depends on 9)

The golf ball of claim 9, wherein said organosulfur compounds include thiophenols, thionaphthols, halogenated thiophenols, and metal salts thereof.

### Claim 11

A golf ball comprising a core and a cover formed of a cover resin composition, wherein said core has a hardness corresponding to a compressive deflection amount of at least 3.5 mm when the load applied thereto is increased from an initial load of 10 kgf to a final load of 130 kgf, said cover resin composition has a melt flow rate of at least 3 as measured according to JIS K7210, and said cover has a gage of up to 1.7 mm and a Shore D hardness of 59 to 61.

### Claim 12 (depends on 11)

The golf ball of claim 11, wherein said core contains an organosulfur compound or organosulfur compounds.

### Claim 13 (depends on 12)

The golf ball of claim 12, wherein said organosulfur compounds include thiophenols, thionaphthols, halogenated thiophenols, and metal salts thereof.