Golf ball

Patent metadata

Field	Value
Publication number	US-9731167-B2
Application number	US-201514981250-A
Country	US
Kind code	B2
Filing date	Dec 28, 2015
Priority date	Dec 26, 2014
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

An object of the present invention is to provide a golf ball striking a good balance between flight distance on driver shots and spin rate on approach shots, and excellent in stain resistance and shot feeling. The present invention provides a golf ball comprising a paint film, wherein a base resin of the paint film contains a polyurethane obtained by a reaction between a polyisocyanate composition and a polyol composition containing a urethane polyol having a polyether diol with a number average molecular weight in a range from 800 to 3,000 as a constituent component, and the following requirements are satisfied:

Mp≦200× X −75

Mp≦100

Minm−Moum>40

Moum−Mc<5

Tinm≧Toum>Tc>Tp

(Tinm×Minm)/(Toum×Moum)>2.0

(Toum×Moum)/(Tc×Mc)<3.0

(Tc×Mc)/(Tp×Mp)>10.0

[where Mp, Minm, Moum, and Mc represent a 10% elastic modulus (kgf/cm 2 ) of the paint film, inner intermediate layer, outer intermediate layer and cover, respectively; Tp, Tinm, Toum, and Tc represent a thicknesses (mm) of the paint film, inner intermediate layer, outer 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.].

First claim

The invention claimed is:

1. A golf ball comprising: a golf ball body including a spherical core, an inner intermediate layer covering the spherical core, an outer intermediate layer covering the inner intermediate layer, and a cover covering the outer intermediate layer; and a paint film formed on a surface of the golf ball body,
wherein a base resin constituting the paint film contains a polyurethane obtained by a reaction between a polyol composition and a polyisocyanate composition,
the polyol composition contains a urethane polyol having a polyether diol with a number average molecular weight in a range from 800 to 3,000 as a constituent component, and
following requirements are satisfied:
Mp≦200× X− 75

Mp≦100

Minm−Moum>40

Moum−Mc <5

Tinm≧Toum>Tc>Tp

(Tinm−Minm)/(Toum−Moum)>2.0

(Toum−Moum)/(Tc−Mc)<3.0

(Tc−Mc)/(Tp−Mp)>10.0

wherein
Mp represents a 10% elastic modulus (kgf/cm 2 ) of the paint film,
Minm represents a 10% elastic modulus (kgf/cm 2 ) of the inner intermediate layer,
Moum represents a 10% elastic modulus (kgf/cm 2 ) of the outer intermediate layer, and
Mc represents a 10% elastic modulus (kgf/cm 2 ) of the cover;
Tp represents a thickness (mm) of the paint film,
Tinm represents a thickness (mm) of the inner intermediate layer,
Toum represents a thickness (mm) of the outer intermediate layer, and
Tc represents a thickness (mm) of the cover; and
X represents a molar ratio (NCO/OH) of isocyanate groups (NCO groups) of the polyisocyanate composition to hydroxyl groups (OH groups) of the polyol composition.

2. The golf ball according to claim 1 , wherein an absolute value (|Mp−Mc |) of a difference between the 10% elastic modulus Mp of the paint film and the 10% elastic modulus Mc of the cover is 65 kgf/cm 2 or less.

3. The golf ball according to claim 1 , wherein a proportion occupied by a volume Vc of the cover in the golf ball body is less than 10 vol. %.

4. The golf ball according to claim 1 , wherein the 10% elastic modulus Mc of the cover is 100 kgf/cm 2 or less.

5. The golf ball according to claim 1 , wherein the 10% elastic modulus Minm of the inner intermediate layer is 120 kgf/cm 2 or more.

6. The golf ball according to claim 1 , wherein a difference (Hs—Ho) between a surface hardness Hs and a center hardness Ho of the spherical core is 20 or more in Shore C hardness.

7. The golf ball according to claim 1 , wherein the spherical core includes at least one layer foamed from a rubber composition containing a fatty acid and/or a metal salt thereof, and wherein the fatty acid and/or the metal salt thereof excludes α,β-unsaturated carboxylic acid having 3 to 8 carbon atoms or a metal salt thereof used as a co-crosslinking agent.

8. The golf ball according to claim 1 , wherein the spherical core is a dual-layered core composed of an inner core and an outer core covering the inner core.

9. The golf ball according to claim 1 , wherein the spherical core has a diameter in a range from 37.0 mm to 40.5 mm.

10. The golf ball according to claim 1 , wherein the urethane polyol has a weight average molecular weight in a range from 5000 to 20,000.

11. The golf ball according to claim 1 , wherein the polyisocyanate composition contains a biuret product and an isocyanurate product of hexamethylene diisocyanate, and a mass ratio (biuret product/isocyanurate product) of the biuret-modified product to the isocyanurate-modified product ranges from 20/40 to 40/20.

12. The golf ball according to claim 1 , wherein the thickness Tinm of the inner intermediate layer ranges from 0.7 mm to 1.6 mm.

13. The golf ball according to claim 1 , wherein the thickness Toum of the outer intermediate layer ranges from 0.5 mm to 1.2 mm.

14. The golf ball according to claim 1 , wherein the thickness Tc of the cover ranges from 0.1 mm to 0.6 mm.

15. The golf ball according to claim 1 , wherein a slab hardness of the inner intermediate layer ranges from 62 to 75 in Shore D hardness.

16. The golf ball according to claim 1 , wherein a slab hardness of the outer intermediate layer ranges from 42 to 63 in Shore D hardness.

17. The golf ball according to claim 1 , wherein a slab hardness of the cover ranges from 40 to 65 in Shore D hardness.

18. The golf ball according to claim 1 , wherein a proportion occupied by a volume Vinm of the inner intermediate layer in the golf ball body is 18.0 vol % or less.

19. The golf ball according to claim 1 , wherein a proportion occupied by a volume Voum of the outer intermediate layer in the golf ball body is 15.0 vol % or less.

20. The golf ball according to claim 1 , wherein the 10% elastic modulus Mourn of the outer intermediate layer is 35 kgf/cm 2 or more.

21. The golf ball according to claim 1 , wherein Mourn−Mc<0.

22. The golf ball according to claim 1 , wherein
(Tinm×Minm)/(Toum×Moum)≦8.0.

23. The golf ball according to claim 1 , wherein in a reaction between the polyol composition and the polyisocyanate composition, a molar ratio (NCO groups/OH groups) of isocyanate groups (NCO groups) of the polyisocyanate composition to hydroxyl groups (OH groups) of the polyol composition is more than 0.5 and 0.85 or less.

Assignees

• Dunlop Sports Co Ltd

Inventors

• Tachibana Kosuke
• Isogawa Kazuhiko
• Tarao Toshiyuki

Classifications

• C08G18/3206

  aliphatic · CPC title

• A63B37/0062

  Hardness · CPC title

• A63B37/0033

  Thickness · CPC title

• C08G18/246

  containing also tin-carbon bonds · CPC title

• A63B37/0096

  Spin rate · CPC title