Multilayer golf ball with a thin thermoset outer layer

• US 8,109,843 B2
• Filed: 06/28/2010
• Issued: 02/07/2012
• 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: Hebert, Edmund A., Cavallaro, Christopher
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US12/824,853
• Publication Number:
  US 20100261553A1
• Time in Patent Office: 589 Days
• Field of Search: 473/376, 473/373, 473/374
• 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 crosslinking agent, wherein the first crosslinking agent is present in a first amount;

an outer core layer disposed about the center to form a core comprising a second resilient rubber-based component comprising a second base rubber and a second crosslinking agent, wherein the second crosslinking agent is present in an second amount of about 20 to about 40 parts per hundred parts of the second base rubber, wherein the second amount is greater than the first amount by at least about 5 parts per hundred, and wherein the second resilient rubber-based component has different physical properties than the first resilient rubber-based component;

an inner cover layer disposed about the core comprising a material having a first Shore D hardness; and

an outer cover layer disposed about the inner cover layer formed from a castable reactive liquid material and having a second Shore D hardness less than the first Shore D hardness.

2. The golf ball of claim 1, wherein the second Shore D hardness is from about 30 to about 60 Shore D, and wherein the first Shore D hardness is from about 65 to about 80 Shore D.

3. The golf ball of claim 1, wherein the first amount is from about 15 to about 25 parts per hundred parts of the first base rubber.

4. The golf ball of claim 1, wherein the inner cover layer comprises an ionomer resin.

5. The golf ball of claim 4, wherein the ionomer resin comprises at least about 16 percent by weight acrylic or methacrylic acid.

6. The golf ball of claim 1, wherein the castable reactive liquid material comprises thermoset polyurethane, thermoset urethane ionomer, or thermoset urethane epoxies.

7. A golf ball comprising:

a center comprising a first resilient rubber-based component comprising a first base rubber and a first crosslinking agent present in a first amount of about 15 to about 25 parts per hundred parts of the first base rubber;

an outer core layer disposed about the center to form a core comprising a second resilient rubber-based component comprising a second base rubber and a second crosslinking agent present in a second amount of about 20 to about 40 parts per hundred parts of the second base rubber, wherein the second amount is greater than the first amount by at least about 5 parts per hundred;

an inner cover layer disposed about the core having a hardness of about 65 to about 80 Shore D; and

an outer cover layer disposed about the inner cover layer having a hardness from about 30 to about 60 Shore D.

8. The golf ball of claim 7, wherein the outer cover layer is cast from thermoset polyurethane, thermoset polyurethane ionomer, or thermoset polyurethane epoxy.

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

10. The golf ball of claim 7, wherein the inner cover layer has a hardness of about 68 to about 72 Shore D.

11. A golf ball comprising:

a center comprising a first resilient rubber-based component comprising a first base rubber and a first crosslinking agent, wherein the first crosslinking agent is present in a first amount;

an outer core layer disposed about the center to form a core comprising a second resilient rubber-based component comprising a second base rubber and a second crosslinking agent, wherein the second crosslinking agent is present in a second amount that is greater than the first amount by at least about 5 parts per hundred, wherein the second amount is from about 20 to about 40 parts per hundred parts of the second base rubber, and wherein the second resilient rubber-based component has different physical properties than the first resilient rubber-based component;

an inner cover layer disposed about the core comprising a material having a first Shore D hardness and a flexural modulus of at least about 65,000 psi, wherein the inner cover layer comprises an ionomer resin comprises at least about 16 percent acrylic or methacrylic acid; and

an outer cover layer disposed about the inner cover layer formed from castable reactive liquid material and having a second Shore D hardness less than the first Shore D hardness.

12. The golf ball of claim 11, wherein the castable reactive liquid material comprises thermoset polyurethane.

13. The golf ball of claim 11, wherein the inner cover layer material has a flexural modulus of at least about 75,000 psi.

14. The golf ball of claim 11, wherein the first amount is about 15 to about 25 parts per hundred of the first base rubber.

15. The golf ball of claim 11, wherein the first Shore D hardness is about 65 to about 80 Shore D and the second Shore D hardness is about 30 to about 60 Shore D.

16. The golf ball of claim 11, wherein the ionomer resin comprises an E/X/Y copolymer, wherein E is ethylene, X is softening comonomer, and Y is acrylic or methacrylic acid, wherein Y is present in an amount at least about 16 percent by weight of the E/X/Y copolymer.

17. The golf ball of claim 11, wherein the outer core layer comprises a plurality of layers.