Game balls with cover containing post crosslinkable thermoplastic polyurethane and method of making same

• US 7,148,266 B2
• Filed: 09/07/2004
• Issued: 12/12/2006
• Est. Priority Date: 12/23/1999
• Status: Expired due to Term

• Current Assignee: Callaway Golf Company
• Original Assignee: Callaway Golf Company
• Inventors: Kennedy, Thomas J. III, Nesbitt, R. Dennis
• Primary Examiner(s): Buttner, David J.
• Application Number:
  US10/935,010
• Publication Number:
  US 20050054746A1
• Time in Patent Office: 826 Days
• Field of Search: None
• US Class Current: 522/145
• CPC Class Codes: A63B 2102/02 Tennis
• CPC Class Codes: A63B 2102/14 Lacrosse
• CPC Class Codes: A63B 2102/18 Baseball, rounders or similar games
• CPC Class Codes: A63B 2102/182 Softball
• CPC Class Codes: A63B 2102/32 Golf
• CPC Class Codes: A63B 2243/0025 Football American football A63B2243/007
• CPC Class Codes: A63B 2243/0037 Basketball
• CPC Class Codes: A63B 2243/0066 Rugby; American football
• CPC Class Codes: A63B 2243/007 American football
• CPC Class Codes: A63B 2243/0095 Volleyball
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: C08G 18/83 Chemically modified polymers
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence

Abstract

A game ball having a cover formed from a crosslinkable thermoplastic polyurethane is disclosed. By selective exposure to radiation, the thermoplastic polyurethane cover is crosslinked and its hardness is increased. Typically, increases in hardness values of at least 2 units on the Shore D scale are realized upon exposure to 3.5 Mrads of gamma radiation.

Claims

1. A golf ball, comprising:

a core, and

a cover layer formed over said core, said cover layer comprising a crosslinkable thermoplastic polyurethane and a co-agent capable of crosslinking said crosslinkable thermoplastic polyurethane via free radical initiation, the co-agent having the formula H₂C═

CH—

(CH₂)_n—

CH═

CH₂ where n is from 1 to 6.

2. The golf ball according to claim 1, wherein said crosslinkable thermoplastic polyurethane has a Shore D hardness of from about 35 to about 72 before crosslinking and undergoes an increase in Shore D hardness of at least 2 units upon exposure to gamma radiation at a dosage of 3.5 Mrads.

3. The golf ball according to claim 1, wherein said crosslinkable thermoplastic polyurethane has a Shore D hardness of from about 35 to about 72 before crosslinking and experiences an increase in Shore D hardness of at least 5 units upon exposure to gamma radiation at a dosage of 3.5 Mrads.

4. The golf ball according to claim 1, wherein said crosslinkable thermoplastic polyurethane comprises at least one of a polyether based polyurethane and a polyester based polyurethane.

5. The golf ball according to claim 1, wherein said core is at least one member selected from the group consisting of solid cores, wound cores and liquid filled cores.

6. A golf ball comprising:

a core; and

a cover layer disposed about said core, said cover comprising a thermoplastic polyurethane capable of undergoing crosslinking upon exposure to about 3.5 Mrads of radiation, and thereby increasing in hardness by at least 2 units on the Shore D hardness scale, wherein said cover layer further comprises a co-agent capable of crosslinking said thermoplastic polyurethane, the a co-agent having the formula H₂C═

CH—

(CH₂)_n—

CH═

CH₂ where n is from 1 to 6.

7. The golf ball according to claim 6, wherein said cover layer comprises at least an inner cover layer and an outer cover layer.