Multi-layer core golf ball

• US 7,354,357 B2
• Filed: 07/24/2006
• Issued: 04/08/2008
• Est. Priority Date: 02/06/2004
• Status: Expired due to Term

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Hebert, Edmund A., Ladd, Derek A.
• Primary Examiner(s): GORDEN, RAEANN
• Application Number:
  US11/459,477
• Publication Number:
  US 20060252577A1
• Time in Patent Office: 624 Days
• Field of Search: 473/373, 473/374, 473/368, 473/376
• US Class Current: 473/373
• CPC Class Codes: A63B 2037/085 liquid, jellylike
• CPC Class Codes: A63B 2209/00 Characteristics of used materials
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0037 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0045 Thickness
• CPC Class Codes: A63B 37/0047 Density; Specific gravity
• CPC Class Codes: A63B 37/0049 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0059 Ionomer
• CPC Class Codes: A63B 37/0061 Coefficient of restitution
• CPC Class Codes: A63B 37/0062 Hardness
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0065 Deflection or compression
• CPC Class Codes: A63B 37/0066 Density; Specific gravity
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/00776 Slab hardness
• CPC Class Codes: A63B 37/0078 Coefficient of restitution
• CPC Class Codes: A63B 37/00922 : whereby hardness of the cover is lower than hardness of the intermediate layers
• CPC Class Codes: A63B 37/02 : Special cores balls with finger holes A63B37/0001, golf ball cores A63B37/005
• CPC Class Codes: A63B 37/04 : Rigid cores
• CPC Class Codes: A63B 45/00 : Apparatus or methods for manufacturing balls working of plastics or substances in a plastic state B29
• CPC Class Codes: B29C 2043/3644 : Vacuum bags; Details thereof, e.g. fixing or clamping
• CPC Class Codes: B29C 43/146 : for making multilayered articles
• CPC Class Codes: B29C 43/18 : incorporating preformed parts or layers, e.g. compression moulding around inserts or for coating articles B29C43/206 takes precedence
• CPC Class Codes: B29C 43/305 : Making multilayered articles
• CPC Class Codes: B29C 70/70 : Completely encapsulating inserts B29C70/86 takes precedence
• CPC Class Codes: B29K 2105/256 : Sheets, plates, blanks or films
• CPC Class Codes: B29L 2031/52 : Sports equipment ; Games; Articles for amusement; Toys B29L2031/54 takes precedence
• CPC Class Codes: B29L 2031/54 : Balls
• CPC Class Codes: C08L 23/08 : Copolymers of ethene C08L23/16 takes precedence
• CPC Class Codes: C08L 2666/04 : Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/14 : Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 2666/24 : Graft or block copolymers according to groups C08L51/00, C08L53/00 or C08L55/02; Derivatives thereof
• CPC Class Codes: C08L 53/02 : of vinyl-aromatic monomers and conjugated dienes
• CPC Class Codes: C08L 75/02 : Polyureas
• CPC Class Codes: C08L 75/04 : Polyurethanes
• CPC Class Codes: C08L 9/00 : Compositions of homopolymers or copolymers of conjugated diene hydrocarbons

Abstract

The present invention is directed to an improved multi-layer golf ball displaying enhanced playing characteristics, including high speed, high launch, and low spin. In general the golf ball displays improved performance in areas such as distance and feel for lower swing speed players. The ball has a relatively large solid inner core, with at least one solid outer core layer surrounding the inner core, and a thin cover layer surrounding the outermost core layer. The inner core is softer than the outer core, which in turn is softer than the cover. The ball may be designed such that the coefficient of restitution (COR) gradient is from slow to fast; that is, the inner core has a lower COR than the total core, which has a lower COR than the entire golf ball.

Claims

1. A golf ball comprising:

an inner core having a compression of less than about 40;

at least one intermediate layer surrounding the inner core, having a hardness of at least about 55 Shore D, and a specific gravity greater than a specific gravity of the inner core; and

a cover surrounding the intermediate layer comprised of an acrylic acid ionomer having an acid content of between 13% and 16%;

wherein the inner core has a hardness less than a hardness of the intermediate layer and wherein a ratio of flexural modulus (ksi) to Shore D hardness for the cover is less than about 1.0 and a first COR of the inner core and the intermediate layer is less than a second COR of the entire ball.

2. The golf ball of claim 1, wherein the intermediate layer has a higher flexural modulus than a flexural modulus of the inner core.

3. The golf ball of claim 1, wherein the inner core has a diameter of about 1.4 inches or less and the intermediate layer has a thickness of about 0.1 inches or less.

4. The golf ball of claim 1, wherein the specific gravity of the inner core is less than about 1.15.

5. The golf ball of claim 4, wherein the specific gravity of the inner core is less than about 1.05.

6. The golf ball of claim 1, wherein the specific gravity of the intermediate layer is greater than about 1.15.

7. The golf ball of claim 6, wherein the specific gravity of the intermediate layer is greater than about 1.20.

8. The golf ball of claim 7, wherein the specific gravity of the intermediate layer is greater than about 1.25.

9. The golf ball of claim 1, wherein the cover has a hardness of at least about 60 Shore D, a modulus of least about 60 ksi, and a thickness of about 0.03 to about 0.5 inches.

10. The golf ball of claim 9, wherein the hardness of the cover is at least about 65 Shore D.

11. A golf ball comprising:

an inner core;

at least one intermediate core layer surrounding the inner core having a specific gravity larger than a specific gravity of the inner core;

at least one outer core layer surrounding the intermediate core layer having a specific gravity larger than the specific gravity of the intermediate core layer; and

a cover surrounding the outer core layer having a specific gravity smaller than the specific gravity of the outer core layer, wherein a ratio of flexural modulus (ksi) to Shore D hardness for the cover is less than about 1.0.

12. The golf ball of claim 11, wherein a volume of the inner core layer is greater than a volume of the outer core layer, and wherein a volume of the cover layer is less than the volume of the outer core layer.

13. The golf ball of claim 11, wherein a hardness of the inner core is less than a hardness of the outer core, and wherein a hardness of the cover is greater than the hardness of the outer core.

14. A golf ball comprising:

an inner core having a compression of less than about 60;

at least one outer core layer surrounding the inner core, having a hardness of at least about 55 Shore D, and a specific gravity greater than a specific gravity of the inner core; and

a cover surrounding the outer core layer;

wherein the inner core has a hardness less than a hardness of the outer core, and wherein the inner core layer comprises a unfilled highly neutralized thermoplastic ionomer (HNP) having a specific gravity of less than 0.95.

15. The golf ball of claim 14, wherein a ratio of the Shore D hardness to the flexural modulus of the cover layer is less than about 1.0.

16. The golf ball of claim 15, wherein said ratio is less than about 0.95.

17. The golf ball of claim 15, wherein said ratio is less than about 0.90.

18. The golf ball of claim 14, wherein the compression of the inner core is less than about 40.

19. The golf ball of claim 18, wherein the compression of the inner core is less than about 30.