Method of making filler-impregnated golf ball core

• US 7,351,370 B2
• Filed: 12/04/2002
• Issued: 04/01/2008
• 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: Morgan, William, Cavallaro, Christopher, Pasqua, Samuel A. Jr.
• Primary Examiner(s): Lee; Edmund H.
• Application Number:
  US10/309,613
• Publication Number:
  US 20030083156A1
• Time in Patent Office: 1,945 Days
• Field of Search: None
• US Class Current: 264/328.1
• CPC Class Codes: A63B 2037/087 Wound cores or layers
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0064 Diameter
• 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: 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 18/3225 Polyamines
• CPC Class Codes: C09D 175/04 Polyurethanes

Abstract

A method of making a golf ball core comprising the steps of providing a first polybutadiene pre-impregnated with at least about 50 weight percent of a first filler; providing a second polybutadiene substantially free of the first filler; providing a free radical initiator and a crosslinking agent; mixing the second polybutadiene, the free radical initiator, and the crosslinking agent with the first polybutadiene to form a polybutadiene blend; and molding the polybutadiene blend into the golf ball core.

Claims

1. A method of making a golf ball core comprising the steps of:

providing a first polybutadiene pre-impregnated with at least about 50 weight percent of tungsten;

providing a second polybutadiene substantially free of tungsten;

mixing the second polybutadiene with the first polybutadiene to form a polybutadiene blend;

mixing a crosslinking agent, and a free radical initiator into the polybutadiene blend to form a reaction mixture;

placing the reaction mixture into a mold cavity;

heating and pressurizing the reaction mixture to form the golf ball core.

2. The method of claim 1, wherein the step of mixing further includes a cis-to-trans catalyst.

3. A method of making a golf ball comprising the steps of:

providing a first polybutadiene pre-impregnated with at least about 50 weight percent of a first filler;

mixing a second polybutadiene, substantially free of the first filler, into the first polybutadiene to form a polybutadiene blend;

mixing a cis-to-trans catalyst, a crosslinking agent, and a free radical initiator into the polybutadiene blend to form a reaction product;

molding the reaction product into a golf ball core; and

forming a cover layer about the core to produce the golf ball.

4. The method of claim 3, wherein the first polybutadiene consists of greater than about 80 percent filler, by weight.

5. The method of claim 3, wherein the second polybutadiene consists of less than about 5 percent filler by weight.

6. The method of claim 5, wherein the second polybutadiene consists of between about 1 percent filler by weight and about 0.05 percent filler by weight.

7. The method of claim 3, wherein at least one of the first or second polybutadiene has a Mooney viscosity of about 40 to about 80.

8. The method of claim 3, wherein the first or second polybutadiene has a first dynamic stiffness measured at −

50°

C. that is less than about 130 percent of a second dynamic stiffness measured at 0°

C.

9. The method of claim 3, wherein the cover layer is formed by injection molding, compression molding, or casting a reactive liquid.

10. The method of claim 3, wherein the cover layer has a thickness of between about 0.05 inches and about 0.1 inches.

11. The method of claim 3, wherein the cover layer has a loss tangent of from about 0.03 to 0.08 between a temperature of −

30°

C. to 20°

C.

12. The method of claim 3, wherein the cover layer has an elasticity and complex modulus of from about 5,000 to 12,000 kgf/cm² over a temperature of about −

30°

C. to 20°

C.

13. The method of claim 3, wherein the cover layer comprises natural or synthetic balata material, thermoset and thermoplastic materials, ionomers, polyamides, polyureas, polyurethanes, and styrene-butadiene rubbers.

14. The method of claim 3, wherein the cover layer has a loss tangent of 0.16 to 0.075 over a range of −

30°

C. to 20°

C.

15. The method of claim 14, wherein the cover layer has a complex modulus of from about 1000 to 2800 kgf/cm² from −

30°

C. to 20°

C.

16. The method of claim 3, wherein the cover is an outer cover layer comprising polyurethane or polyurea.