Golf balls with soft, resilient bimodal ionomeric covers

• US 8,193,283 B2
• Filed: 12/05/2008
• Issued: 06/05/2012
• Est. Priority Date: 08/11/2000
• Status: Expired due to Fees

• Current Assignee: Performance Materials NA, Inc. (Dow, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Chen, John Chu
• Primary Examiner(s): BUTTNER, DAVID J
• Application Number:
  US12/315,731
• Publication Number:
  US 20090182089A1
• Time in Patent Office: 1,278 Days
• Field of Search: None
• US Class Current: 525/196
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0023 Covers
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0037 Flexural modulus; Bending stiffness
• CPC Class Codes: A63B 37/0073 Solid, i.e. formed of a single piece
• CPC Class Codes: A63B 37/0074 Two piece balls, i.e. cover and core
• CPC Class Codes: A63B 37/0083 Weight; Mass
• CPC Class Codes: A63B 37/0095 Scuff resistance
• 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: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof

Abstract

Disclosed are golf balls having soft, resilient bimodal ionomeric covers with improved softness and scuff resistance and methods for their preparation. The soft, resilient bimodal ionomeric covers comprise at least partially neutralized mixtures of carboxylate functionalized terpolymers (molecular weight between about 80,000 and 500,000) with carboxylate functionalized ethylene low copolymers (molecular weight between about 2,000 and 30,000).

Claims

1. A golf ball having a cover, wherein the cover comprises a thermoplastic composition that includes:

(a) at least one E/X/Y copolymer having a weight average molecular weight (M_w) of from about 80,000 to about 500,000 obtained by the copolymerization of comonomers E, X, and Y wherein E is ethylene, X is a C₃ to C₈ α

,β

-ethylenically unsaturated carboxylic acid, and Y is an alkyl acrylate or an alkyl methacrylate softening comonomer wherein the alkyl groups have from 1 to 8 carbon atoms, wherein X is present in an amount of from about 2 to about 30 wt. % of the E/X/Y copolymer, and Y is present in an amount of from about 17 to about 35 wt. % of the E/X/Y copolymer;

(b) one or more E/acrylic acid and/or E/methacrylic acid copolymers having a weight average molecular weight of from about 2,000 to about 30,000 and having from about 3 to about 20 wt. % acrylic acid and/or methacrylic acid present based on the weight of (b), the copolymer present in the composition in an amount of from about 5 to about 30 wt. % based on the combined weight of (a)+(b);

and wherein the thermoplastic composition is at least partially neutralized by one or more alkali metal, transition metal, or alkaline earth metal ionic.

2. The golf ball of claim 1 wherein at least 30% of the acid moieties of the composition are neutralized.

3. The golf ball of claim 2 wherein at least 45% of the acid moieties of the composition are neutralized.

4. The golf ball of claim 1 wherein the neutralizing agent has a cation selected from the group consisting of zinc, magnesium and lithium.

5. The golf ball of claim 4 wherein the neutralizing agent has a zinc cation.

6. The golf ball of claim 1 wherein the cover further comprises at least one thermoplastic polymer selected from the group consisting of copolyetheresters, copolyetheramides, elastomeric polyolefins, styrene diene block copolymers and thermoplastic.

7. The golf ball of claim 6 wherein at least 30% of the acid moieties of the composition are neutralized.

8. The golf ball of claim 7 wherein at least 45% of the acid moieties of the composition are neutralized.

9. The golf ball of claim 6 wherein the neutralizing agent has a cation selected from the group consisting of zinc, magnesium and lithium.

10. The golf ball of claim 8 wherein the neutralizing agent has a zinc cation.

11. A one-piece golf ball comprising a thermoplastic composition that includes:

(a) at least one E/X/Y copolymer having a weight average molecular weight of from about 80,000 to about 500,000 obtained by the copolymerization of comonomers E, X, and Y wherein E is ethylene, X is a C₃ to C₈ α

,β

-ethylenically unsaturated carboxylic acid, and Y is an alkyl acrylate or an alkyl methacrylate softening comonomer wherein the alkyl groups have from 1 to 8 carbon atoms, wherein E is present in an amount of from about 30 wt % to about 81 wt % based on the weight of the copolymer, X is present in an amount of from about 2 to about 30 wt. % of the copolymer, Y is present in an amount of from about 17 to about 35 wt. % of the copolymer;

(b) one or more E/acrylic acid and/or E/methacrylic acid copolymers having a weight average molecular weight of from about 2,000 to about 30,000 and having from about 3 to about 20 wt. % acrylic acid and/or methacrylic acid present based on the weight of (b), the copolymer present in the composition in an amount of from about 5 to about 30 wt. % based on the combined weight of (a)+(b);

and wherein the thermoplastic composition is at least partially neutralized by one or more alkali metal, transition metal, or alkaline earth metal.

12. The golf ball of claim 11, further comprising at least one thermoplastic polymer selected from the group consisting of copolyetheresters, copolyetheramides, elastomeric polyolefins, styrene diene block copolymers and thermoplastic polyurethanes.

13. The golf ball of claim 11 wherein at least 30% of the acid moieties of the composition are neutralized.

14. The golf ball of claim 13 wherein at least 45% of the acid moieties of the composition are neutralized.

15. The golf ball of claim 14 wherein the neutralizing agent has a cation selected from the group consisting of zinc, magnesium and lithium.

16. The golf ball of claim 15 wherein the neutralizing agent has a zinc cation.

17. The golf ball of claim 11 wherein sufficient filler is added to adjust the mass of the golf ball to a level meeting the limits set by the golfer'"'"'s governing authority.