Foam-core golf balls

• US 20060073914A1
• Filed: 11/21/2005
• Published: 04/06/2006
• Est. Priority Date: 05/29/2002
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Hebert, Edmund A., Ladd, Derek A.
• Granted Patent: US 7,708,654 B2
• Time in Patent Office: Days
• US Class Current: 473/371
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0041 Coefficient of restitution
• CPC Class Codes: A63B 37/0047 Density; Specific gravity
• CPC Class Codes: A63B 37/0082 Density; Specific gravity

Abstract

A golf ball with a controlled moment of inertia and controlled spin rate is disclosed. The ball has an intermediate layer positioned between the core and the cover and the intermediate layer has a reduced specific gravity. Preferably, this reduction is less than about 30% in specific gravity and the reduction in the coefficient of restitution is less than about 2%.

Claims

1. A golf ball comprising a core, an intermediate layer and a cover, wherein the intermediate layer is comprised of a highly neutralized polymer has its specific gravity reduced to less than 1.05 and wherein the reduction in specific gravity of the intermediate layer is between 3% and 15% to minimize the reduction in the coefficient of restitution of the ball.

2. The golf ball of claim 1, wherein the core is comprised of a polybutadiene.

3. The golf ball of claim 1, wherein the reduction in specific gravity is caused by foaming.

4. The golf ball of claim 1, wherein the reduction in specific gravity is caused by expandable microspheres.

5. The golf ball of claim 1, wherein the highly neutralized thermoplastic polymer comprises a copolymer of ethylene and an α

,β

-unsaturated carboxylic acid or a terpolymer of ethylene, an α

,β

-unsaturated carboxylic acid, and an n-alkyl acrylate, the acid being at least 80% neutralized by a salt of an organic acid, a cation source, or a suitable base of the organic acid.

6. The golf ball of claim 5, wherein the highly neutralized polymer is fully neutralized by a salt of an organic acid, a cation source or a suitable base of the organic acid.

7. The golf ball of claim 1, wherein the highly neutralized polymer comprises a melt processible thermoplastic composition comprising (a) aliphatic, mono-functional organic acid(s) having fewer than 36 atoms and (b) an ethylene, C_3-8 alpha, beta-ethylenically unsaturated carboxylic acid copolymer(s) and ionomer(s) thereof.

8. The golf ball of claim 1, wherein the highly neutralized polymer comprises (a) a salt of a high molecular weight organic acid and (b) an acid containing copolymer ionomer.

9. The golf ball of claim 8, wherein the highly neutralized polymer further comprises (c) a thermoplastic polymer selected from co-polyesteresters, copolyetheramides, block styrene polydiene thermoplastic elastomers, elastomeric polyolefins, and thermoplastic polyurethanes.

10. The golf ball of claim 1, wherein the diameter of the core and intermediate layer is from 1.45 inches to 1.66 inches.

11. The golf ball of claim 1, wherein the ball has a moment of inertia of greater than 85 g·

cm and the core has a reduced of specific gravity of at least 3%.

12. The golf ball of claim 1, wherein the ball has a moment of inertia of greater than 85 g·

cm and further comprises a thin dense layer having a specific gravity of greater than 2 surrounding the intermediate layer.

13. A golf ball comprising a sub-assembly of at least a core and an intermediate layer, wherein the subassembly has a diameter of at least 1.45 inches and the core has a diameter of 0.75 inch or less, wherein the specific gravity of the intermediate layer is reduced by 3% to 15% and the reduction in coefficient of restitution of the subassembly is less than 6%.

14. A golf ball comprising a sub-assembly of at least a core and an intermediate layer, wherein the subassembly has a diameter of at least 1.45 inches and the core has a diameter of 0.75 inch or less, wherein the wherein the specific gravity of the intermediate layer is reduced by 15% to 32% and the reduction in coefficient of restitution of the subassembly is less than 13%.

15. The golf ball of claim 14, wherein at least the intermediate layer is made from a highly neutralized polymer.

16. A golf ball comprising a subassembly of at least a core and an intermediate layer, wherein subassembly is encased in a cover, wherein the intermediate layer has its specific gravity reduced to less than 0.95 and the specific gravity of the subassembly is reduced by 2% to 5% and the reduction in coefficient of restitution of the subassembly is reduced less than 2%.

17. A golf ball comprising a subassembly of at least a core and an intermediate layer, wherein subassembly is encased in a cover, wherein the intermediate layer has its specific gravity reduced to less than 0.95 and wherein the specific gravity of the subassembly is reduced by 5% to 8% and the reduction in coefficient of restitution of the subassembly is less than 3%.

18. The golf ball of claim 17, wherein at least the intermediate layer of the golf ball is made from a highly neutralized polymer.

19. The golf ball of claim 18, wherein the core is made from the highly neutralized polymer.