# US 10,369,419 B2 · Golf ball

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- Number: US 10,369,419 B2
- Document ID: US10369419B2
- Status: Granted
- Kind: B2
- Application number: 15/624,842
- Filed: 2017-06-16
- Published: 2017-10-05
- Granted: 2019-08-06
- Earliest claimed: 2013-09-03
- Assignees: Bridgestone Sports Co., Ltd.
- Applicants: Bridgestone Sports Co., Ltd.
- Inventors: Kae Ilzuka; Tsuyoshi Nakajima; Yuichiro Ozawa
- Web page: https://patentgrep.com/patent/US10369419B2

## CPC

- A63B 37/0074: {Two piece balls, i.e. cover and core}
- A63B 37/0024: {Materials other than ionomers or polyurethane}
- A63B 37/0051: {Materials other than polybutadienes; Constructional details}
- A63B 37/006: {Physical properties}
- A63B 37/0063: {Hardness gradient}
- A63B 37/0064: {Diameter}
- A63B 37/0065: {Deflection or compression}
- A63B 37/0066: {Density; Specific gravity}
- A63B 37/0068: {Initial velocity}
- A63B 37/0075: {Three piece balls, i.e. cover, intermediate layer and core}
- A63B 37/0076: {Multi-piece balls, i.e. having two or more intermediate layers}
- C08L 21/00: Compositions of unspecified rubbers
- A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

The invention provides a golf ball having a core and a cover of one layer or a plurality of layers, wherein the core is formed of a material molded under heat from a rubber composition containing (A) a base rubber, (B) an organic peroxide, and (C) water and/or a metal monocarboxylate, and has a hysteresis loss of 50% or less when compressed at a load cell speed of 500 mm/min and under a constant load of 5,000 N.

## Claims

### Claim 1

A golf ball comprising a core and a cover of one layer or a plurality of layers, wherein the core is formed of a material molded under heat from a rubber composition comprising the following components A to C:
(A) a base rubber,
(B) an organic peroxide, and
(C) water,
wherein the golf ball has a hardness at an interior thereof such that a value obtained by subtracting a JIS-C hardness H5.0 at a position 5.0 mm outward from a center of the core and toward a periphery of the core from a JIS-C hardness H15.0 at a position 15.0 mm outward from the core center and toward the core periphery is a positive value and not more than 18.3,
wherein the amount of the water included per 100 parts by weight of the base rubber serving as component A is from 0.1 to 5 parts by weight.

### Claim 2 (depends on 1)

The golf ball of claim 1, wherein the core has a JIS-C hardness difference obtained by subtracting a hardness at the center of the core from a hardness at a surface of the core which is at least 20.

### Claim 3 (depends on 1)

The golf ball of claim 1, wherein the core has a diameter of not more than 42.0 mm and a deflection when compressed under a final load of 1,275 N (130 kgf) from an initial load state of 98 N (10 kgf) of from 2.0 to 6.0 mm.

### Claim 4 (depends on 1)

The golf ball of claim 1, wherein the rubber composition before vulcanization has a moisture content of at least 1,000 ppm.

### Claim 5 (depends on 1)

The golf ball of claim 1, wherein the rubber composition includes from 0.1 to 5 parts by weight of an organosulfur compound per 100 parts by weight of the base rubber.

### Claim 6 (depends on 1)

The golf ball of claim 1, wherein the core after vulcanization has a higher moisture content at a center of the core than at a surface of the core.

### Claim 7 (depends on 1)

The golf ball of claim 1, wherein a product P×E of a difference P (mol/m3) in cros slink density between a surface of the core and a center of the core, as measured based on a toluene swelling test, multiplied by a deflection E (mm) of the core when compressed under a final load of 1,275 N (130 kgf) from an initial load state of 98 N (10 kgf) is at least 28×102 mol/m3·mm.

### Claim 8 (depends on 1)

The golf ball of claim 1 wherein, when a loss tangent of a center of the core is measured at a temperature of −12° C. and a frequency of 15 Hz, letting tan δ1 be a loss tangent at a dynamic strain of 1% and tan δ10 be a loss tangent at a dynamic strain of 10%, the slope of these tan δ values, expressed as [(tan δ10−tan δ1)/(10%−1%)], is not more than 0.003.

### Claim 9 (depends on 1)

The golf ball of claim 1, wherein each layer of the cover has a thickness in a range of from 0.5 to 2.5 mm.

### Claim 10 (depends on 1)

The golf ball of claim 1, wherein at least one layer of the cover is formed of a resin composition containing at least one of (I) and (II) below:
(I) an ionic or nonionic olefin-unsaturated carboxylic acid copolymer,
(II) an ionic or nonionic olefin-unsaturated carboxylic acid-carboxylic acid ester copolymer.

### Claim 11 (depends on 10)

The golf ball of claim 10, wherein copolymers (I) and (II) have a base monomer that is ethylenic.

### Claim 12 (depends on 10)

The golf ball of claim 10, wherein the carboxylic acid in ionic copolymers (I) and (II) is at least 30 mol % neutralized.

### Claim 13 (depends on 1)

The golf ball of claim 1, wherein the core has a hysteresis loss of 50% or less when compressed at a load cell speed of 500 mm/min and under a constant load of 5,000 N.

### Claim 14 (depends on 1)

The golf ball of claim 1, wherein a moisture content at the core center is from 1,000 to 7,000 ppm.

### Claim 15 (depends on 1)

The golf ball of claim 1, wherein tan δ10 is a loss tangent at a dynamic strain of 10%, and tan δ10 is from 0.053 to 0.066.

### Claim 16 (depends on 1)

The golf ball of claim 1, wherein a lower limit of the value obtained by subtracting the JIS-C hardness H5.0 from the JIS-C hardness H15.0 is 11.4.

### Claim 17

A golf ball comprising a core and a cover of one layer or a plurality of layers, wherein the core is formed of a material molded under heat from a rubber composition comprising the following components A to C:
(A) a base rubber,
(B) an organic peroxide, and
(C) water and/or a metal monocarboxylate,
wherein the golf ball has a hardness at an interior thereof such that a value obtained by subtracting a JIS-C hardness H5.0 at a position 5.0 mm outward from a center of the core and toward a periphery of the core from a JIS-C hardness H15.0 at a position 15.0 mm outward from the core center and toward the core periphery is a positive value and not more than 18.3,
wherein the core has a JIS-C hardness difference obtained by subtracting a hardness at the center of the core from a hardness at a surface of the core which is at least 20.

### Claim 18 (depends on 17)

The golf ball of claim 17, wherein a lower limit of the value obtained by subtracting the JIS-C hardness H5.0 from the JIS-C hardness H15.0 is 11.4.

### Claim 19

A golf ball comprising a core and a cover of one layer or a plurality of layers, wherein the core is formed of a material molded under heat from a rubber composition comprising the following components A to C:
(A) a base rubber,
(B) an organic peroxide, and
(C) water and/or a metal monocarboxylate,
wherein the golf ball has a hardness at an interior thereof such that a value obtained by subtracting a JIS-C hardness H5.0 at a position 5.0 mm outward from a center of the core and toward a periphery of the core from a JIS-C hardness H15.0 at a position 15.0 mm outward from the core center and toward the core periphery is a positive value and not more than 18.3,
wherein a moisture content at the core center is from 1,000 to 7,000 ppm.

### Claim 20 (depends on 19)

The golf ball of claim 19, wherein a lower limit of the value obtained by subtracting the JIS-C hardness H5.0 from the JIS-C hardness H15.0 is 11.4.