Multi-layer core golf ball

• US 8,303,438 B2
• Filed: 02/28/2011
• Issued: 11/06/2012
• Est. Priority Date: 02/06/2004
• Status: Active Grant

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Ladd, Derek A., Hebert, Edmund A.
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US13/036,586
• Publication Number:
  US 20110152009A1
• Time in Patent Office: 617 Days
• Field of Search: 473/376, 473/373, 473/374
• US Class Current: 473/376
• 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 70 and a hardness of less than 80 Shore C and an inner core specific gravity;

at least one intermediate layer surrounding the inner core having a specific gravity from about 1 to 2 and having a hardness greater than the inner core hardness;

an outer core layer surrounding the intermediate layer having a hardness greater than the inner core and greater than 80 Shore C and having an outer core layer specific gravity that is greater than the inner core specific gravity; and

a cover layer comprised of an ionomer blend surrounding the outer core layer;

wherein a ratio of flexural modulus (ksi) to Shore D hardness for the cover is less than about 1.0.

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

3. The golf ball of claim 1, wherein the inner core has a diameter of about 1.4 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 1, wherein the specific gravity of the outer core layer is greater than about 1.1.

6. The golf ball of claim 1, wherein the cover layer has a specific gravity that is less than the outer core layer specific gravity.

7. The golf ball of claim 1, wherein each successive intermediate layer comprises a larger specific gravity than a preceding intermediate layer closer to the inner core.