Multilayer golf ball with a thin thermoset outer layer

• US 7,335,114 B2
• Filed: 10/28/2005
• Issued: 02/26/2008
• Est. Priority Date: 05/27/1997
• Status: Expired due to Fees

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Cavallaro, Christopher, Hebert, Edmund A.
• Primary Examiner(s): GORDEN, RAEANN
• Application Number:
  US11/260,169
• Publication Number:
  US 20060046873A1
• Time in Patent Office: 851 Days
• Field of Search: 473/376, 473/373, 473/368
• US Class Current: 473/376
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0049 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/00922 whereby hardness of the cover is lower than hardness of the intermediate layers
• 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: B29C 35/02 Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mouldcold vulcanisation B29C35/18 ; vulcanising tyres, presses therefor B29D30/0601
• CPC Class Codes: B29C 39/00 Shaping by casting, i.e. introducing the moulding material into a mould or between confining surfaces without significant moulding pressure; Apparatus therefor B29C41/00 takes precedence
• CPC Class Codes: B29C 45/00 Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor injection blow-moulding B29C49/06
• CPC Class Codes: B29D 99/0042 Producing plain balls hollow balls B29D22/04
• CPC Class Codes: B29L 2031/54 Balls
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 23/08 Copolymers of ethene C08L23/16 takes precedence
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof

Abstract

The present invention is directed towards a method of forming a multilayer golf ball which comprises a core, an inner cover layer and an outer cover layer. The steps include forming a golf ball core; molding an inner cover layer around said golf ball core with a material having a first shore D hardness; and casting an outer cover layer around said inner cover layer and golf ball core with a thermoset material having a second shore D hardness less than the first. The core is comprised of a center made from a first rubber based material and an outer layer formed from a second rubber based material. Preferably, the first rubber based material has about 15 to 25 parts of a crosslinking agent per hundred parts of rubber and the second rubber based material has about 20 to 40 parts of a crosslinking agent per hundred parts of rubber.

Claims

1. A golf ball comprising:

a center comprising a first resilient rubber-based component comprising a first base rubber and a first amount of crosslinking agent, wherein the first amount is about 19 to about 25 parts per hundred of the first base rubber;

an outer core layer comprising a second resilient rubber-based component comprising a second base rubber and a second amount of crosslinking agent, wherein the second amount is about 30 to about 38 parts per hundred of the second base rubber;

an inner cover layer formed from a material having a flexural modulus of at least about 65,000 psi and a first Shore D hardness; and

an outer cover layer formed from a thermoset material and having a thickness of less than 0.05 inches and a second Shore D hardness less than the first Shore D hardness.

2. The golf ball of claim 1, wherein the outer cover has a thickness of less than about 0.02 inches to about 0.04 inches.

3. The golf ball of claim 1, wherein the thermoset material comprises polyurethane.

4. The golf ball of claim 1, wherein the inner cover layer is formed from a material having a flexural modulus of at least about 75,000 psi.

5. The golf ball of claim 1, wherein the inner cover layer is formed from an ionomer resin.

6. The golf ball of claim 1, wherein the first Shore D hardness is about 68 to about 74.

7. A golf ball comprising:

a center comprising a first resilient rubber-based component comprising a first base rubber and a first amount of crosslinking agent, wherein the first amount is about 19 to about 25 parts per hundred of the base rubber;

an outer core layer comprising a second resilient rubber-based component comprising a second base rubber and a second amount of crosslinking agent, wherein the second amount is about 30 to about 38 parts per hundred of the second base rubber;

an inner cover layer having a Shore D hardness of about 68 to about 74; and

an outer cover layer formed from a castable reactive liquid material, wherein the outer cover layer has a thickness of less than 0.05 inches and a Shore D hardness of about 50 to about 60.

8. The golf ball of claim 7, wherein the castable reactive liquid material comprises polyurethane.

9. The golf ball of claim 7, wherein the inner cover layer comprises ionomer resin.

10. The golf ball of claim 7, wherein the first and second resilient rubber-based components each further comprise an initiator agent.

11. The golf ball of claim 7, wherein the first and second resilient rubber-based components have different physical properties.

12. A golf ball comprising:

a center comprising a first resilient rubber-based component comprising a first base rubber and a first amount of crosslinking agent, wherein the first amount is about 19 to about 25 parts per hundred of the first base rubber;

an outer core layer comprising a second resilient rubber-based component comprising a second base rubber and a second amount of crosslinking agent, wherein the second amount is about 30 to about 38 parts per hundred of the second base rubber;

an inner cover layer comprising ionomer resin having a Shore D hardness of about 68 to about 74; and

an outer cover layer comprising polyurethane, wherein the outer cover layer has a thickness of about 0.02 inches to about 0.04 inches and a Shore D hardness of about 50 to about 60.

13. The golf ball of claim 12, wherein the polyurethane is thermoset.

14. The golf ball of claim 12, wherein the inner cover layer has a thickness of about 0.02 inches to about 0.045 inches.

15. The golf ball of claim 12, wherein the ionomer resin has a flexural modulus of at least about 75,000 psi.