Method of forming a multilayer golf ball with a thin thermoset outer layer

• US 6,749,789 B1
• Filed: 07/25/2000
• Issued: 06/15/2004
• Est. Priority Date: 05/27/1997
• Status: Expired due to Term

• Current Assignee: Acushnet Company (FILA Holdings Corp.)
• Original Assignee: Acushnet Company (FILA Holdings Corp.)
• Inventors: Hebert, Edmund A., Snell, Dean, Morgan, William E.
• Primary Examiner(s): Lee, Edmund H.
• Application Number:
  US09/625,544
• Time in Patent Office: 1,421 Days
• Field of Search: 264/250, 264/255, 264/279.1, 264/275, 264/325
• US Class Current: 264/250
• CPC Class Codes: A63B 2037/087 Wound cores or layers
• 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 37/0045 Thickness
• CPC Class Codes: A63B 37/0054 Substantially rigid, e.g. metal
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• 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: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/3225 Polyamines
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 23/0876 Neutralised polymers, i.e. ionomers
• CPC Class Codes: C09D 175/04 Polyurethanes

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; forming an inner cover layer around golf ball core with a material having a first shore D hardness; and casting an outer cover layer around inner cover layer and golf ball core with a thermoset material having a second shore D hardness less than the first. The inner cover layer is formed of a material having a shore D hardness that is about 5 to about 50 greater than the shore D hardness of the thermoset material forming the outer cover layer.

Claims

1. A method of forming a golf ball comprising the steps of

(a) forming a golf ball core;

(b) compression molding an inner cover layer around said golf ball core with a material having a first shore D hardness, thereby forming a coated golf ball core; and

(c) 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, wherein casting the outer cover layer comprises;

(i) placing the inner cover layer and the golf ball core in core holder;

(ii) gelling the thermoset material in the first mold half;

(iii) placing the inner cover layer and the golf ball core in to the gelling thermoset material in the first mold half,

(iv) disengaging the inner cover layer and the golf ball core from the core holder after a selected period of time;

(v) placing the inner cover layer and the golf ball core, while still in said first mold half with the thermoset material against a second mold half having additional thermoset material and mating the two mold halves together; and

(vi) curing the thermoset material in the mated mold halves.

2. The method of claim 1, wherein the inner cover layer is formed of a material having a shore D hardness that is about 5 to about 50 greater than the shore D hardness of the thermoset material forming the outer cover layer.

3. The method of claim 1, wherein the inner cover layer is formed from at least one material selected from the group consisting of an ionomer resin, a polyurethane, a polyetherester, a polyetheramide, a polyester, a dynamically vulcanized elastomer, a functionalized styrene-butadiene elastomer, a metallocene polymer, nylon, and acrylonitrilebutadiene-styrene copolymer.

4. The method of claim 1, wherein the outer cover layer thermoset material has a shore D hardness in the range of about 30 to 60.

5. The method of claim 4, wherein the outer cover layer thermoset material has a shore D hardness in the range of about 35 to 50.

6. The method of claim 1, wherein the thermoset material of the outer cover layer comprises at least one of a thermoset urethane, a polyurethane, a thermoset urethane ionomer, or a thermoset urethane epoxy.

7. The method of claim 1, wherein the outer cover layer has a thickness of less than about 0.05 inches.