Golf ball core having medium positive hardness gradient and high surface hardness

• US 9,155,938 B2
• Filed: 03/06/2014
• Issued: 10/13/2015
• Est. Priority Date: 11/28/2001
• Status: Expired due to Fees

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Sullivan, Michael J., Comeau, Brian, Britton, Dennis
• Primary Examiner(s): Gorden, Raeann
• Application Number:
  US14/108,644
• Publication Number:
  US 20140295996A1
• Time in Patent Office: 586 Days
• Field of Search: 473/376
• US Class Current: 1/1
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0039 characterised by the material
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0044 Hardness gradient
• CPC Class Codes: A63B 37/00621 Centre hardness
• CPC Class Codes: A63B 37/00622 Surface hardness
• CPC Class Codes: A63B 37/0063 Hardness gradient
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0066 Density; Specific gravity
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/0092 Hardness distribution amongst different ball layers
• CPC Class Codes: A63B 37/02 Special cores balls with finger holes A63B37/0001, golf ball cores A63B37/005

Abstract

A golf ball includes a single solid core having a surface hardness and a geometric center hardness. The core has an outer diameter of about 1.5 to 1.62 inches. An outer cover layer formed from a polyurea or polyurethane has a first hardness, and an inner cover layer, disposed between the core and the outer cover, has a second hardness greater than the first hardness and within 5 Shore C of the core surface hardness. The geometric center hardness is about 64 to 85 Shore C, and the core surface hardness is greater than 85 Shore C and harder than the geometric center hardness by about 5 to 22 Shore C to define a positive hardness gradient.

Claims

1. A golf ball comprising:

a core comprising an inner core layer and an outer core layer, the inner core layer having a geometric center hardness of about 66 to 82 Shore C and a surface hardness of 62 to 78 Shore C and being softer than the center hardness to define a negative hardness gradient;

an outer cover layer comprising a polyurea, a polyurethane, or a hybrid thereof, the outer cover layer having a Vicker'"'"'s hardness of about 0.18 to 0.40 as measured on the ball at 0.49 N with a 10-s hold time; and

an inner cover layer comprising ionomer and being disposed between the core and the outer cover layer;

wherein the outer core layer comprises a stiffening thermoplastic polymer, has a surface hardness of 86 to 96 Shore C, and is harder than the geometric center by about 10 to 20 Shore C to define a positive hardness gradient.

2. The golf ball of claim 1, wherein the geometric center hardness is about 67 Shore C to about 80 Shore C.

3. The golf ball of claim 1, wherein the geometric center hardness is about 70 Shore C to about 80 Shore C.

4. The golf ball of claim 1, wherein the outer cover layer Vicker'"'"'s hardness is about 0.2 to 0.35 as measured on the ball at 0.49 N with a 10-s hold time.

5. The golf ball of claim 1, wherein the inner or outer core layers comprise a polybutadiene rubber and about 1 to 100 phr of a stiffening thermoplastic polymer.

6. The golf ball of claim 5, wherein the stiffening thermoplastic polymer comprises polyisoprene, trans butadiene rubbers, ionomer, acid co- or ter-polymers, polyamides, polyesters, polyoctenemers, styrene butadiene copolymers, polyether-esters, polyamide-esters, or polyethylene copolymers.

7. The golf ball of claim 1, wherein the inner or outer cover layers further comprise a polyurea, a polyurethane, a urethane-urea hybrid, a urea-urethane hybrid, a castable epoxy, a metallocene-catalyzed polyolefin, ionomers, ethylene-acrylic or -methacrylic acid copolymers or terpolymers, highly-neutralized ionomers, thermoset diene rubbers, polyether-esters, polyamide-esters, or polyether-amides.

8. The golf ball of claim 1, wherein the core diameter is about 1.53 to 1.58 inches.