Multi-layer core golf ball

• US 9,737,764 B2
• Filed: 09/30/2015
• Issued: 08/22/2017
• Est. Priority Date: 08/05/2013
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Comeau, Brian, Goguen, Douglas S.
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US14/870,468
• Publication Number:
  US 20160016048A1
• Time in Patent Office: 692 Days
• Field of Search: 473373, 473374
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0062 Hardness
• 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 37/0083 Weight; Mass
• CPC Class Codes: A63B 37/0087 Deflection or compression
• CPC Class Codes: A63B 37/0092 Hardness distribution amongst different ball layers
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C08L 9/00 Compositions of homopolymers or copolymers of conjugated diene hydrocarbons

Abstract

Golf ball incorporating core consisting of: a solid inner core layer consisting of a peroxide cured polybutadiene rubber composition and having a diameter of 1.25 inches or less and a center Shore C hardness (H_center) of 50 or less; and an outer core layer consisting of a thermoplastic composition Tc as defined herein and having a thickness of 0.400 inches or greater and an outer surface Shore C hardness (H_{outer surface}) of 70 or greater, wherein H_{outer surface}>H_center, and H_{outer surface}−H_center≧40. The peroxide cured polybutadiene rubber composition may comprise a reaction product of polybutadiene and a sufficient amount of peroxide to form the solid inner layer having the center Shore C hardness (H_center) of 50 or less. In one embodiment, 100 phr polybutadiene and from about 0.05 phr to about 3.0 phr of peroxide are mixed with at least one of 5 phr or less of a metal oxide; 5 phr or less of a metal coagent; or 5 phr or less of a metal carbonate. Alternatively, the solid inner core layer has a diameter of 1.10 inches or less or less than 1.0 inches.

Claims

1. A golf ball comprising a core and a cover, wherein the core consists of:

a solid inner core layer consisting of a peroxide cured polybutadiene rubber composition and having a diameter of 1.25 inches or less and a center Shore C hardness (H_center) of 50 or less; and

an outer core layer consisting of a thermoplastic composition Tc and having a thickness of 0.400 inches or greater and an outer surface Shore C hardness (H_{outer surface}) of 70 or greater,

wherein H_{outer surface}>

H_center, and H_{outer surface}−

H_center≧

40.

2. The golf ball of claim 1, wherein the peroxide cured polybutadiene rubber composition comprises a reaction product of polybutadiene and a sufficient amount of peroxide.

3. The golf ball of claim 2, wherein 100 phr polybutadiene and from about 0.05 phr to about 3.0 phr of peroxide are mixed with at least one of 5 phr or less of a metal oxide;

5 phr or less of a metal coagent;

or 5 phr or less of a metal carbonate.

4. The golf ball of claim 2, wherein the polybutadiene and peroxide are mixed with at least one filler, antioxidant, processing agent, light stabilizer, colorant, adhesion promotor, or combinations thereof.

5. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

45.

6. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

50.

7. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

55.

8. The golf ball of claim 1, wherein H_{outer surface}−

H_center≧

60.

9. The golf ball of claim 1, wherein the inner core layer has an inner core interface Shore C hardness H_{inner core interface} such that −

5≦

H_{inner core interface}−

H_center≦

5.

10. The golf ball of claim 1, wherein the outer core layer has an outer core interface Shore C hardness H_{outer core interface} such that H_{outer core interface}−

H_{inner core interface}≦

H_{outer surface}−

H_center.

11. The golf ball of claim 1, wherein the outer core layer has an outer core interface Shore C hardness H_{outer core interface} such that H_{outer core interface}−

H_{inner core interface}>

H_{outer surface}−

H_center.

12. The golf ball of claim 1, wherein Tc is formed from a highly neutralized polymer composition comprising:

an acid copolymer of ethylene and an α

,β

-unsaturated carboxylic acid, optionally including a softening monomer selected from the group consisting of alkyl acrylates and methacrylates;

a non-acid polymer selected from the group consisting of polyolefins, polyamides, polyesters, polyethers, polyurethanes, metallocene-catalyzed polymers, single-site catalyst polymerized polymers, ethylene propylene rubber, ethylene propylene diene rubber, styrenic block copolymer rubbers, alkyl acrylate rubbers, and functionalized derivatives thereof;

an organic acid or salt thereof; and

a cation source present in an amount sufficient to neutralize greater than 80% of all acid groups present in the composition.

13. The golf ball of claim 12, further comprising an intermediate layer disposed between the core and the cover comprising at least one of ionomers;

highly neutralized ionomers;

non-ionomeric acid polymers;

polyurethanes, polyureas, and polyurethane-polyurea hybrids;

polyester-based thermoplastic elastomers;

polyamides, copolymers of ionomer and polyamide, polyamide-ethers, and polyamide-esters;

ethylene-based homopolymers and copolymers;

propylene-based homopolymers and copolymers;

triblock copolymers based on styrene and ethylene/butylene;

derivatives thereof that are compatibilized with at least one grafted or copolymerized functional group; and

combinations thereof.

14. The golf ball of claim 12, further comprising an intermediate layer disposed between the core and the cover comprising at least one of natural rubber, polybutadiene, polyisoprene, ethylene propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), styrene-butadiene rubber, butyl rubber, halobutyl rubber, polyurethane, polyurea, acrylonitrile butadiene rubber, polychloroprene, alkyl acrylate rubber, chlorinated isoprene rubber, acrylonitrile chlorinated isoprene rubber, polyalkenamer, phenol formaldehyde, melamine formaldehyde, polyepoxide, polysiloxane, polyester, alkyd, polyisocyanurate, polycyanurate, polyacrylate, and combinations thereof.

15. The golf ball of claim 12, wherein the solid inner core layer has a center Shore C hardness (H_center) of 40 or less, the outer core layer has an outer surface Shore C hardness (H_{outer surface}) of 85 or greater, and wherein H_{outer surface}>

H_center, and H_{outer surface}−

H_center≧

45.

16. The golf ball of claim 12, wherein the diameter of the solid inner core layer is 1.10 inches or less.

17. The golf ball of claim 12, wherein the diameter of the solid inner core layer is less than 1.0 inch.