Interpenetrating polymer networks using blocked polyurethane/polyurea prepolymers for golf ball layers

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

providing a first polymeric precursor comprising a polyurethane or polyurea prepolymer having blocked isocyanate groups and a first curing agent;

providing a second polymeric precursor comprising an epoxy resin;

adding a second curing agent to the second polymeric precursor to form a second polymeric system wherein the second curing agent is substantially unreactive with the first polymeric precursor;

combining the first polymeric precursor and second polymeric system in a vessel;

elevating the temperature in the vessel to an amount sufficient to unblock the isocyanate groups in the first polymeric component to provide a first polymeric system resulting in an interpenetrating polymer network (“IPN”) comprising the first and second polymeric systems; and

forming the IPN into the portion of the golf ball, wherein the step of adding occurs prior to the steps of combining and elevating.

2. The method of claim 1 , wherein at least about 80 percent of the isocyanate groups are blocked.

3. The method of claim 1 , wherein the step of providing the first polymeric precursor further comprises the steps of:

providing an isocyanate having terminal isocyanate groups;

providing a polyol or amine-terminated component;

reacting the isocyanate and polyol or amine-terminated component to form a prepolymer;

blocking the terminal isocyanate groups; and

adding the first curing agent.

4. The method of claim 3 , wherein the step of blocking the terminal isocyanate groups further comprises the steps of:

providing a blocking agent; and

blocking the terminal isocyanate groups with the blocking agent to form a blocked prepolymer.

5. The method of claim 4 , wherein the blocking agent comprises linear and branched alcohols; phenols and phenol derivatives; oximes; lactams; lactones; β-dicarbonyl compounds; hydroxamic acid esters; bisulfite addition compounds; hydroxylamines; esters of p-hydroxybenzoic acid; N-hydroxyphthalimide; N-hydroxysuccinimide; triazoles; substituted imidazolines; tetrahydropyrimidines; caprolactones; or mixtures thereof.

6. The method of claim 1 , wherein the step of providing the first polymeric precursor further comprises the steps of:

providing an isocyanate having terminal isocyanate groups;

providing a blocking agent;

reacting the isocyanate and blocking agent to form a half-blocked intermediate;

providing a polyol or amine-terminated component;

reacting the half-blocked intermediate with a polyol or amine-terminated component to form a prepolymer; and

adding the first curing agent.

7. The method of claim 6 , wherein the blocking agent comprises linear and branched alcohols; phenols and phenol derivatives; oximes; lactams; lactones; β-dicarbonyl compounds; hydroxamic acid esters; bisulfite addition compounds; hydroxylamines; esters of p-hydroxybenzoic acid; N-hydroxyphthalimide; N-hydroxysuccinimide; triazoles; substituted imidazolines; tetrahydropyrimidines; caprolactones; or mixtures thereof.

8. The method of claim 1 , wherein the IPN is included in a cover layer disposed about a center.

9. The method of claim 1 , wherein the second curing agent is substantially unreactive with the first polymeric precursor.

10. A method of forming a portion of a golf ball comprising the steps of:

providing a first polymeric component comprising an isocyanate, a polyol or amine-terminated component and a blocked, delayed action curative;

providing a second polymeric component comprising an epoxy resin or acrylate resin;

reacting the second polymeric component with a second curing agent to form a second polymeric system, wherein the second curing agent is substantially unreactive with first polymeric component;

combining the first polymeric component and second polymeric system;

exposing the first polymeric component to elevated temperature to form a first polymeric system resulting in an interpenetrating network (“IPN”) comprising the first and second polymeric systems; and

forming the IPN into the portion of the golf ball,

wherein the step of reacting occurs prior to the steps of combining and exposing.

11. The method of claim 10 , wherein the step of providing the first polymeric component further comprises the steps of:

providing an isocyanate having terminal isocyanate groups; and

reacting the isocyanate and a polyol or amine-terminated component to form a prepolymer.

12. The method of claim 10 , wherein the step of providing the first polymeric component further comprises the steps of:

providing an isocyanate having terminal isocyanate groups;

reacting the isocyanate and polyol or amine-terminated component to form a prepolymer; and

adding the blocked, delayed action curative to the prepolymer.

13. The method of claim 10 , wherein the blocked, delayed action curative comprises a diamine.

14. The method of claim 10 , wherein the step of providing the first polymeric component further comprises the steps of:

providing an isocyanate having terminal isocyanate groups;

reacting the isocyanate and the blocked, delayed action curative to form a half-blocked intermediate;

reacting the half-blocked intermediate with the polyol or amine-terminated component to form a prepolymer.

15. The method of claim 14 , wherein the blocked, delayed action curative comprises methylene dianiline.

16. The method of claim 10 , wherein the second curing agent comprises a catalyst complex comprising BF 3 and 4-chlorobenzenamine.