Golf ball

• US 6,251,030 B1
• Filed: 07/02/1999
• Issued: 06/26/2001
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: SRI Sports Limited (Sumitomo Rubber Industries Limited)
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Kato, Akira, Yabuki, Yoshikazu
• Primary Examiner(s): Gerrity, Stephen F.
• Assistant Examiner(s): Kim, Paul D
• Application Number:
  US09/346,541
• Time in Patent Office: 725 Days
• Field of Search: 473/365, 473/363, 473/371, 473/372, 473/373, 473/374, 473/375
• US Class Current: 473/365
• CPC Class Codes: A63B 2037/087 Wound cores or layers
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0024 Materials other than ionomers or polyurethane
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0036 Melt flow rate [MFR]
• CPC Class Codes: A63B 37/0037 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0052 Liquid cores
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0083 Weight; Mass
• CPC Class Codes: A63B 37/0084 Initial velocity
• CPC Class Codes: A63B 37/0096 Spin rate
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/03 containing three or more polymers in a blend
• CPC Class Codes: C08L 23/0869 Acids or derivatives thereof
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 51/06 grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
• CPC Class Codes: C08L 53/00 Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 53/005 : Modified block copolymers
• CPC Class Codes: C08L 53/02 : of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C08L 55/00 : Compositions of homopolymers or copolymers, obtained by polymerisation reactions only involving carbon-to-carbon unsaturated bonds, not provided for in groups C08L23/00 - C08L53/00

Abstract

The present invention provides a multi-layer structure golf ball having a thread rubber layer, which has good shot feel and controllability as well as satisfactory flight performance and cut resistance. The golf ball includes a thread wound core and a cover covering the thread wound core, wherein the cover is formed from a heated mixture of:

(A) an ionomer resin,

(B) a thermoplastic elastomer having a carboxyl group or a thermoplastic elastomer having a terminal OH group, and

(C) a block copolymer having a styrene-butadiene-styrene structure in which the polybutadiene block contains epoxy groups, or a block copolymer having styrene-isoprene-styrene structure in which the polyisoprene block contains epoxy groups,

the cover has a flexural modulus of from 50 to 300 MPa and a Shore D-scale hardness of from 40 to 60.

Claims

1. A golf ball comprising a thread wound core and a cover covering the thread wound core, wherein the cover is formed from a heated mixture of:

(A) an ionomer resin,

(B) a thermoplastic elastomer having a terminal OH group, and

(C) a block copolymer having a styrene-butadiene-styrene structure in which the polybutadiene block contains epoxy groups, or a block copolymer having styrene-isoprene-styrene structure in which the polyisoprene block contains epoxy groups.

2. The golf ball according to claim 1, wherein the ionomer resin is obtained by neutralizing at least a portion of carboxyl groups in a copolymer of ethylene and acrylic or methacrylic acid with metal ion and/or obtained by neutralizing at least a portion of carboxyl groups in a terpolymer of ethylene, acrylic or methacrylic acid and an α

,β

-unsaturated carboxylate with metal ion, which has an acid content of from 10 to 20% by weight, when its backbone is a copolymer of ethylene and acrylic or methacrylic acid, or has an acid content of from 5 to 20% by weight, when its backbone is a terpolymer of ethylene, acrylic or methacrylic acid and an α

,β

-unsaturated carboxylate.

3. The golf ball according to claim 1, wherein the ionomer resin is obtained by neutralizing at least a portion of carboxyl groups in a copolymer of ethylene and acrylic or methacrylic acid with metal ion, which has a melt index of 3 to 7 and a flexural modulus of 200 to 400 MPa.

4. The golf ball according to claim 1, wherein the thermoplastic elastomer having a terminal OH group is a block copolymer having a styrene-hydrogenated butadiene-styrene structure with a terminal OH group or a block copolymer having a styrene-hydrogenated isoprene-styrene structure with a terminal OH group.

5. The golf ball according to claim 1, wherein the thread wound core is composed of a center and a thread rubber layer formed by winding a thread rubber around the center, and the center is a solid center and a diameter of the center is from 28 to 38 mm and a deformation amount of 0.5 to 2.5 mm, the deformation amount being determined by applying a weight of from an initial load of 10 Kg to a final load of 30 Kg on the solid center and measuring a change of the deformation of the solid conter by mm.

6. The golf ball according to claim 1, wherein the thread wound core is composed of a center and a thread rubber layer formed by winding a thread rubber around the center, and the center is a liquid center and a diameter of the center is from 26 to 34 mm.

7. The golf ball according to claim 1, wherein the cover has a flexural modulus of from 130 to 275 MPa and a Shore D-scale hardness of from 40 to 60.

8. The golf ball according to claim 1, wherein the cover has a flexural modulus of from 50 to 300 MPa and a Shore D-scale hardness of from 40 to 60.