Multilayer golf ball with a thin thermoset outer layer

• US 7,090,798 B2
• Filed: 03/22/1999
• Issued: 08/15/2006
• 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): Lee, Edmund H.
• Application Number:
  US09/274,015
• Publication Number:
  US 20010009310A1
• Time in Patent Office: 2,703 Days
• Field of Search: 473/373, 473/372, 473/374, 473/375, 473/357, 473/377, 264/250, 264/255, 264/248, 264/278, 264/279.1
• US Class Current: 264/255
• 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 method of forming a golf ball comprising the steps of:

forming a core comprising;

a solid center made from a first rubber based material;

a solid outer layer made from a second rubber based material having different physical properties from said first rubber based material;

injection molding an inner cover layer made from a material having a first shore D hardness from about 65 to about 74 shore D and having an outer diameter of at least 1.6 inches;

casting a dimpled outer cover layer made from a thermoset material having a second shore D hardness less than the first shore D hardness of the material of the inner cover layer.

2. The method of claim 1 wherein the outer cover layer has a hardness of from about 30 to about 60 Shore D.

3. The method of claim 2 wherein the inner cover layer material has a hardness from about 68 to about 72 Shore D.

4. The method of claim 2 wherein the outer cover layer has a hardness from about 40 to about 60 Shore D.

5. The method of claim 4 wherein the hardness of the outer cover is from about 50 to about 60 Shore D.

6. The method of claim 1 wherein the core outer layer has a first crosslinking agent in an amount from about 20 to about 40 parts per hundred of rubber.

7. The method of claim 6 wherein the amount of first crosslinking agent in the core outer layer is from about 30 to about 38 parts per hundred of rubber.

8. The method of claim 6 wherein the core outer layer has from about 10 to about 17 parts of balata per hundred parts of rubber.

9. The method of claim 1 wherein the center has a second crosslinking agent in an amount from about 15 to about 25 parts per hundred of rubber.

10. The method of claim 9 wherein the amount of the second crosslinking agent in the center is from about 19 to about 25 parts per hundred of rubber.

11. A method of forming a golf ball comprising the steps of:

forming a core comprising;

a solid center made from a first rubber based material;

a solid core outer layer made from a second rubber based material having different physical properties from said first rubber based material;

injection molding an inner cover layer comprising a material having a first shore D hardness and having an outer diameter of at least 1.58 inches;

casting a dimpled outer cover layer comprising a thermoset castable reactive liquid material having a second shore D hardness less than the first shore D hardness.

12. The method of claim 11 wherein the outer cover layer has a hardness from about 30 Shore D to about 60 Shore D.

13. The method of claim 12 wherein the outer cover layer has a hardness from about 40 Shore D to about 60 Shore D.

14. The method of claim 13 wherein the outer cover layer has a hardness from about 50 Shore D to about 60 Shore D.

15. The method of claim 11 wherein the inner cover layer has a flexural modulus of about 65,000 psi or more.

16. The method of claim 15 wherein the inner cover layer has a hardness from about 65 Shore D to about 74 Shore D.

17. The method of claim 16 wherein the inner cover layer has a hardness from about 68 Shore D to about 72 Shore D.

18. The method of claim 11 wherein the outer diameter of the inner cover layer is from about 1.6 inches to about 1.63 inches.

19. The method of claim 18 wherein the outer diameter of the inner cover layer is from about 1.62 inches to about 1.63 inches.

20. The method of claim 11 wherein the center has an outer diameter from about 0.75 inches to about 1.3 inches.

21. The method of claim 20 wherein the center has an outer diameter from about 1 inch to about 1.15 inches.

22. The method of claim 11 wherein the outer diameter of the core outer layer is from about 1.55 inches to about 1.58 inches.

23. The method of claim 11 wherein the core outer layer has a first crosslinking agent in an amount from about 20 to about 40 parts per hundred of rubber.

24. The method of claim 23 wherein the amount of first crosslinking agent in the core outer layer is from about 30 to about 38 parts per hundred of rubber.

25. The method of claim 23 wherein the core outer layer has from about 10 to about 17 parts of balata per hundred parts of rubber.

26. The method of claim 11 wherein the center has a second crosslinking agent in an amount from about 15 to about 25 parts per hundred of rubber.

27. The method of claim 26 wherein the amount of second crosslinking agent in the center is from about 19 to about 25 parts per hundred of rubber.

28. A method of forming a golf ball comprising the steps of:

forming a core comprising;

a solid center made from a first rubber based material;

a solid outer layer made from a second rubber based material having different physical properties from said first rubber based material;

injection molding an inner cover layer made from a material having a first shore D hardness and having an outer diameter of at least 1.58 inches;

casting a dimpled outer cover layer having a thickness of about 0.05 inches or less made from a thermoset material having a second Shore D hardness less than the first shore D hardness of the material of the inner cover layer.

29. The method of claim 28 wherein the outer cover layer has a hardness of about 30 Shore D to about 60 Shore D.

30. The method of claim 28 wherein the inner cover layer has a hardness of about 65 to about 74 Shore D.

31. The method of claim 28 wherein the outer cover layer has a thickness of about 0.02 inches to about 0.04 inches.