Multi-piece solid golf ball

• US 6,576,707 B2
• Filed: 12/12/2001
• Issued: 06/10/2003
• Est. Priority Date: 12/12/2000
• Status: Expired due to Term

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Sumitomo Rubber Industries Limited
• Inventors: Endo, Seiichiro, Ohama, Keiji
• Primary Examiner(s): Buttner, David J.
• Application Number:
  US10/012,534
• Publication Number:
  US 20020173380A1
• Time in Patent Office: 545 Days
• Field of Search: 525/93, 473/373, 473/374
• US Class Current: 525/93
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0065 Deflection or compression
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0078 Coefficient of restitution
• CPC Class Codes: A63B 37/00921 whereby hardness of the cover is higher than hardness of the intermediate layers
• CPC Class Codes: C08L 23/08 Copolymers of ethene C08L23/16 takes precedence
• 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 2666/24 Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 53/02 of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C08L 53/025 modified

Abstract

The present invention provides a multi-piece solid golf ball having very good shot feel, excellent durability and excellent flight performance. The present invention relates to a multi-piece solid golf ball comprising a core, an inner cover and outer cover, wherein the inner cover has a Shore D hardness of 30 to 62, and is formed from an inner cover composition comprising (a) 50 to 95 parts by weight of ethylene-(meth)acrylic acid copolymer ionomer resin, and (b) 5 to 50 parts by weight of thermoplastic elastomer formed from a polymer alloy of an olefin with a block copolymer having styrene block, based on 100 parts by weight of a base resin; the outer cover is formed from a composition comprising ionomer resin as a main component, and has a Shore D hardness of 58 to 68; and the hardness of the outer cover is higher than that of the inner cover.

Claims

1. A multi-piece solid golf ball comprising a core, an inner cover formed on the core and an outer cover covering the inner cover, wherein

the inner cover has a Shore D hardness of 30 to 62, and is formed from an inner cover composition comprising

(a) 50 to 95 parts by weight of ethylene-(meth)acrylic acid copolymer ionomer resin, and

(b) 5 to 50 parts by weight of thermoplastic elastomer formed from a polymer alloy of an polyolefin with a block copolymer having styrene block, based on 100 parts by weight of a base resin, and the block copolymer having styrene block is selected from the group consisting of styrene-butadiene-styrene block copolymer (SBS), hydrogenation product of SBS, styrene-isoprene-styrene block copolymer (SIS), hydrogenation product of SIS, styrene-isoprene-butadiene-styrene block copolymer (SIBS), and hydrogenation product of SIBS,

the outer cover is formed from an outer cover composition comprising ionomer resin as a main component, and has a Shore D hardness of 58 to 68, and

the hardness of the outer cover is higher than that of the inner cover.

2. The multi-piece solid golf ball according to claim 1, wherein the thermoplastic elastomer has a Shore A hardness of not more than 95.

3. The multi-piece solid golf ball according to claim 1, wherein a ratio (t₁/t₀) of a thickness of the inner cover (t₁) to that of the outer cover (t₀) is within the range of 0.8 to 1.2.

4. The multi-piece solid golf ball according to claim 1, wherein the core has a deformation amount of 3.5 to 6.0 mm, when applying from an initial load of 98 N to a final load of 1275 N.