Golf ball

• US 8,501,871 B2
• Filed: 07/06/2009
• Issued: 08/06/2013
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Dunlop Sports Co. Ltd. (Sumitomo Rubber Industries Limited)
• Inventors: Okabe, Satoko, Ohama, Keiji
• Primary Examiner(s): BUTTNER, DAVID J
• Application Number:
  US12/498,138
• Publication Number:
  US 20100009776A1
• Time in Patent Office: 1,492 Days
• Field of Search: None
• US Class Current: 525/179
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/004 Physical properties
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/0086 Flexural modulus; Bending stiffness
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 33/10 Homopolymers or copolymers of methacrylic acid esters
• CPC Class Codes: C08L 77/00 Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain of polyhydrazides C08L79/06; of polyamideimides or polyamide acids C08L79/08; Compositions of derivatives of such polymers

Abstract

An object of the present invention is to provide a golf ball having an excellent properties like flight distance and low temperature durability. The present invention provides a golf ball comprising: a core consisting of a center and one or more intermediate layers covering the center; and a cover covering the core, wherein at least one piece or one layer of said intermediate layers is formed from a highly elastic intermediate layer composition that contains (A) a highly elastic polyamide resin having a flexural modulus in a range from 700 MPa to 5,000 MPa; (B) a metal-neutralized product of ethylene-(meth)acrylic acid copolymer and (C) a resin having a polar functional group in a specific way.

Claims

1. A golf ball comprising:

an outer core consisting of an inner core and one or more intermediate layers covering the inner core; and

a cover covering the outer core,

wherein the inner core consists of a center and a surrounding layer disposed outside the center, and the inner core has a surface hardness H4 which is equal to or less than the surface hardness H6 of the outer core, and the cover has a hardness H7 of 50 or less in Shore D hardness,

wherein the intermediate layer is formed from a highly elastic intermediate layer composition that contains

(A) a highly elastic polyamide resin having a flexural modulus in a range from 700 MPa to 5,000 MPa;

(B) a metal-neutralized product of ethylene-(meth)acrylic acid copolymer in an amount ratio ((A)/(B)) of (A) the highly elastic polyamide resin to (B) the metal-neutralized product of ethylene-(meth)acrylic acid copolymer being (20 mass % to 80 mass %)/(80 mass % to 20 mass %) (the total is 100 mass %); and

(C) a resin having a polar functional group in an amount of 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of the sum of (A) the highly elastic polyamide resin and (B) the metal-neutralized product of ethylene-(meth)acrylic acid copolymer.

2. The golf ball according to claim 1, wherein the hardness H4 is in a range from 45 to 65 in Shore D hardness.

3. The golf ball according to claim 2, wherein the outer core has a surface hardness H6 in a range from 65 to 80 in Shore D hardness.

4. The golf ball according to claim 3, wherein the intermediate layer has a hardness H5 in a range from 65 to 75 in Shore D hardness.

5. The golf ball according to claim 4, wherein the intermediate layer has a flexural modulus in a range from 300 MPa to 1,000 MPa.

6. The golf ball according to claim 5, wherein the intermediate layer has a tensile strength in a range from 400 MPa to 1,500 MPa.

7. The golf ball according to claim 6, wherein the surrounding layer is formed from a rubber composition with a thickness in a range from 3 mm to 17 mm, and the center has a diameter in a range from 5 mm to 35 mm and a compression deformation amount in a range from 4.0 mm to 10.0 mm when applying an initial load of 98 N to a final load of 1275 N to the center.

8. The golf ball according to claim 6, wherein the surrounding layer is formed from a resin composition with a thickness in a range from 0.2 mm to 3.0 mm, and the center has a diameter in a range from 31 mm to 41 mm and a compression deformation amount in a range from 2.0 mm to 5.0 mm when applying an initial load of 98 N to a final load of 1275 N to the center.

9. The golf ball according to claim 6, wherein the cover has a thickness of 0.8 mm or less.

10. The golf ball according to claim 1, wherein (A) the highly elastic polyamide resin is at least one selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, polyamide 6T, polyamide 61, polyamide 9T, polyamide MST, and polyamide 612 and (C) the resin having a polar functional group is at least one selected from a group consisting of an ethylene-glycidyl methacrylate copolymer, an ethylene-acrylic acid-glycidyl methacrylate copolymer, and a methyl methacrylate-glycidyl methacrylate copolymer.