GOLF BALL

• US 20150273276A1
• Filed: 03/30/2015
• Published: 10/01/2015
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: Dunlop Sports Co. Ltd. (Sumitomo Rubber Industries Limited)
• Inventors: ISOGAWA, Kazuhiko, TACHIBANA, Kosuke, TARAO, Toshiyuki
• Granted Patent: US 9,533,196 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A63B 37/00222 Physical properties, e.g. hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0037 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0049 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0063 Hardness gradient
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/3206 aliphatic
• CPC Class Codes: C08G 18/4854 Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
• CPC Class Codes: C08G 18/6677 having at least three hydroxy groups
• CPC Class Codes: C08G 18/722 Combination of two or more aliphatic and/or cycloaliphatic polyisocyanates
• CPC Class Codes: C08G 18/755 and at least one isocyanate or isothiocyanate group linked to a secondary carbon atom of the cycloaliphatic ring, e.g. isophorone diisocyanate
• CPC Class Codes: C08G 18/7831 containing biuret groups
• CPC Class Codes: C08G 18/792 formed by oligomerisation of aliphatic and/or cycloaliphatic isocyanates or isothiocyanates
• CPC Class Codes: C09D 175/08 from polyethers

Abstract

An object of the present invention is to provide a golf ball striking a good balance between a flight distance on driver shots and a spin rate on approach shots, and excellent in stain resistance and a shot feeling. The present invention provides a golf ball comprising an intermediate layer, a cover, and a paint film, wherein a base resin of the paint film is a polyurethane obtained by a reaction between a polyisocyanate composition and a polyol composition containing a urethane polyol including a polyether diol with a number average molecular weight ranging from 800 to 3000 as a constituent component, and the golf ball satisfies the following requirements;

Mp≦200×X−75

Mp≦100

Mm−Mc>100

Tm>Tc>Tp

(Tm×Mm)/(Tc×Mc)>7.5

(Tc×Mc)/(Tp×Mp)>2.4.

[Mp, Mm and Mc represent 10% modulus (kgf/cm²) of the paint film, intermediate layer and cover, respectively; Tp, Tm and Tc represent thicknesses (mm) of the paint film, intermediate layer and cover, respectively; and X represents a molar ratio (NCO/OH) of a NCO group in the polyisocyanate composition to a OH group in the polyol composition.]

Claims

1. A golf ball comprising a golf ball body having a spherical core, an intermediate layer covering the spherical core and a cover covering the intermediate layer, and a paint film formed on a surface of the golf ball body,

wherein a base resin constituting the paint film is a polyurethane obtained by a reaction between a polyol composition and a polyisocyanate composition,

the polyol composition contains a urethane polyol including a polyether diol with a number average molecular weight ranging from 800 to 3000 as a constituent component, and

a 10% modulus Mp (kgf/cm²) of the paint film, a 10% modulus Mm (kgf/cm²) of the intermediate layer, a 10% modulus Mc (kgf/cm²) of the cover, a thickness Tp (mm) of the paint film, a thickness Tm (mm) of the intermediate layer, a thickness Tc (mm) of the cover, and a molar ratio (NCO/OH) X of an isocyanate group (NCO) in the polyisocyanate composition to a hydroxyl group (OH) in the polyol composition satisfy following requirements;

Mp≦

200×

X−

75

Mp≦

100

Mm−

Mc>

100

Tm>

Tc>

Tp

(Tm×

Mm)/(Tc×

Mc)>

7.5

(Tc×

Mc)/(Tp×

Mp)>

2.4.

2. The golf ball according to claim 1, further comprises an envelope layer disposed between the intermediate layer and the cover, wherein the 10% modulus Mm (kgf/cm²) of the intermediate layer, a 10% modulus Me (kgf/cm²) of the envelope layer, the 10% modulus Mc (kgf/cm²) of the cover, the thickness Tp (mm) of the paint film, the thickness Tm (mm) of the intermediate layer, a thickness Te (mm) of the envelope layer, and the thickness Tc (mm) of the cover satisfy following requirements;

Mm−

Me>

50

Me−

Mc>

55

Tm≧

Te>

Tc>

Tp

(Tm×

Mm)/(Te×

Me)>

1.8

(Te×

Me)/(Tc×

Mc)>

8.0

3. The golf ball according to claim 1, wherein an absolute value (|Mp−

Mc|) of a difference between the 10% modulus Mp (kgf/cm²) of the paint film and the 10% modulus Mc (kgf/cm²) of the cover is 65 kgf/cm² or less.

4. The golf ball according to claim 1, wherein a ratio of a volume Vc of the cover to a volume of the golf ball body is less than 10 vol %.

5. The golf ball according to claim 1, wherein the 10% modulus Mc (kgf/cm²) of the cover is 20 kgf/cm² or less.

6. The golf ball according to claim 1, wherein the 10% modulus Mm (kgf/cm²) of the intermediate layer is 120 kgf/cm² or more.

7. The golf ball according to claim 1, wherein the spherical core has a hardness difference (Hs−

Ho) between a surface hardness Hs and a center hardness Ho thereof of 20 or more in JIS-C hardness.

8. The golf ball according to claim 1, wherein the spherical core comprises at least one layer formed from a rubber composition containing a fatty acid and/or a metal salt thereof.

9. The golf ball according to claim 1, wherein the spherical core is a two layered core consisting of a spherical inner core and an outer core covering the inner core.

10. The golf ball according to claim 1, wherein a ratio of a volume Vm of the intermediate layer to a volume of the golf ball body ranges from 8 vol % to 20 vol %.

11. The golf ball according to claim 2, wherein a ratio of a volume Vm of the intermediate layer to a volume of the golf ball body ranges from 7.0 vol % to 18.0 vol %.

12. The golf ball according to claim 2, wherein a ratio of a volume Ve of the envelope layer to a volume of the golf ball body ranges from 6.0 vol % to 15.0 vol %.