Golf ball

• US 20050107189A1
• Filed: 09/10/2004
• Published: 05/19/2005
• Est. Priority Date: 11/17/2003
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: SRI Sports Limited (Sumitomo Rubber Industries Limited)
• Inventors: Endo, Seiichiro, Ohama, Keiji, Sajima, Takahiro
• Granted Patent: US 7,691,010 B2
• Time in Patent Office: Days
• US Class Current: 473/371
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 37/0006 Arrangement or layout of dimples
• CPC Class Codes: A63B 37/0012 Dimple profile, i.e. cross-sectional view
• CPC Class Codes: A63B 37/0017 Specified total dimple volume
• CPC Class Codes: A63B 37/0018 Specified number of dimples
• CPC Class Codes: A63B 37/002 Specified dimple diameter
• CPC Class Codes: A63B 37/0021 Occupation ratio, i.e. percentage surface occupied by dimples
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/12 Special coverings , i.e. outer layer material balls with finger holes A63B37/0001, golf ball covers A63B37/0023
• CPC Class Codes: C08F 220/14 Methyl esters , e.g. methyl (meth)acrylate
• CPC Class Codes: C08F 236/06 Butadiene
• CPC Class Codes: C08F 265/04 on to polymers of esters
• CPC Class Codes: C08F 279/02 on to polymers of conjugated dienes
• CPC Class Codes: C08F 285/00 Macromolecular compounds obtained by polymerising monomers on to preformed graft polymers
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 2666/06 : Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof
• 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

Abstract

A golf ball 2 has a core, a mid layer and a cover. This mid layer comprises 10 parts by weight or greater and 70 parts by weight or less of a thermoplastic elastomer containing a styrene block having a material hardness of less than 10, and 30 parts by weight or greater and 90 parts by weight or less of an ethylene-(meth)acrylic acid copolymer based ionomer resin having a material hardness of 50 or greater and 70 or less. Hardness of this mid layer is less than 40, and the thickness is equal to or less than 1.2 mm. This golf ball 2 has seven kinds of dimples (Ato G), each having a different diameter. When all the dimples are arranged in decreasing order of the diameter Di, ratio (Dx/Dn) of the mean diameter Dx of the dimples ranking in the top 10% to the mean diameter Dn of the dimples ranking in the bottom 10% is equal to or greater than 1.30. Standard deviation η of diameters of all the dimples is equal to or less than 0.52

Claims

1. A golf ball which comprises a core, a mid layer and a cover,

said mid layer comprising 10 parts by weight or greater and 70 parts by weight or less of a thermoplastic elastomer containing a styrene block having the material hardness of less than 10, and 30 parts by weight or greater and 90 parts by weight or less of an ethylene-(meth)acrylic acid copolymer based ionomer resin having the material hardness of 50 or greater and 70 or less, per 100 parts by weight of the base polymer,

hardness of said mid layer being less than 40,

thickness of said mid layer being equal to or less than 1.2 mm,

said golf ball having three or more kinds of dimples, each having a different diameter, on the surface thereof,

occupation ratio of total area of the dimples in the surface area of a phantom sphere being equal to or greater than 75%,

Dx/Dn being equal to or greater than 1.30, when a mean diameter of the dimples having a diameter ranking in the top 10% of the diameters of all the dimples is defined as Dx and a mean diameter of the dimples having a diameter ranking in the bottom 10% of the diameters of all the dimples is defined as Dn, and

standard deviation η

of diameters of all the dimples being equal to or less than 0.52.

2. The golf ball according to claim 1 wherein said cover comprises 1 part by weight or greater and 30 parts by weight or less of a thermoplastic elastomer containing a styrene block having a material hardness of less than 10, and 50 parts by weight or greater and 99 parts by weight or less of an ethylene-(meth)acrylic acid copolymer based ionomer resin having a material hardness of 50 or greater and 70 or less, per 100 parts by weight of the base polymer,

hardness of said cover being equal to or greater than 55, and

thickness of said cover being 1.0 mm or greater and 1.8 mm or less.

3. The golf ball according to claim 1 wherein the mean value of the diameters of all the dimples is equal to or greater than 4.00 mm.

4. The golf ball according to claim 1 which comprises five or more kinds of dimples, each having a different diameter, on the surface thereof.