Interpenetrating polymer networks using blocked polyurethane/polyurea prepolymers for golf ball layers
View Patent ↗The present invention is directed to a method of forming a golf ball that contains an interpenetrating polymer network, or IPN, which includes at least two polymeric systems, in one or more of the layers. The first polymeric system may include a polyurethane-based or polyurea-based system having blocked isocyanate groups and the second polymeric system may include an epoxy-based or acrylic-based system, wherein the two systems are polymerized or cured simultaneously or sequentially to form an IPN.
1. A golf ball comprising at least one layer formed from an interpenetrating polymer network comprising:
a first polymeric system comprising the reaction product of a polyurethane prepolymer cured with a first curing agent, wherein the prepolymer comprises an isocyanate having terminal isocyanate groups, a blocking agent and a polyol; and
a second polymeric system comprising the reaction product of an epoxy resin and a second curing agent, wherein the first and second polymeric systems are not chemically bonded to each other.
2. The golf ball of claim 1 , wherein the blocking agent is selected from the group consisting of 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; and mixtures thereof.
3. The golf ball of claim 2 , wherein the blocking agent is selected from the group consisting of phenols, branched alcohols, methyl ethyl ketoxime, ε-caprolactam, ε-caprolactone, and mixtures thereof.
4. The golf ball of claim 1 , wherein the second curing agent is selected from the group consisting of anhydrides, Lewis bases, amines, amides, Lewis acids, and mixtures thereof.
5. The golf ball of claim 1 , wherein at least about 80 percent of the terminal isocyanate radicals groups are blocked.
6. The golf ball of claim 5 , wherein at least about 95 percent or more of the terminal isocyanate groups are blocked.
7. The golf ball of claim 1 , wherein the at least one layer comprises a cover layer.
8. The golf ball of claim 7 , wherein the cover layer comprise an inner cover layer and an outer cover layer, and wherein the outer cover layer comprises the interpenetrating polymer network.
9. A golf ball comprising a core and a cover, wherein a portion of the golf ball is formed from an interpenetrating polymer network comprising:
a first polymeric system comprising the reaction product of an isocyanate having terminal isocyanate groups, a polyol, and a blocked, delayed action curative; and
a second polymeric system comprising the reaction product of an epoxy resin and a curing agent, wherein the IPN is substantially free of inter-crosslinks between the first and second polymeric systems.
10. The golf ball of claim 9 , wherein the curing agent is selected from the group consisting of anhydrides, Lewis bases, amines, amides, Lewis acids, and mixtures thereof.
11. The golf ball of claim 9 , wherein the golf ball further comprises an intermediate layer formed of a thermoplastic material.
12. The golf ball of claim 9 , wherein the blocked delayed action amine curative comprises methylene dianiline and sodium chloride.
13. The golf ball of claim 12 , wherein the blocked delayed action amine curative has a deblocking temperature of about 175° F. to about 350° F.
14. The golf ball of claim 9 , wherein at least about 95 percent or more of the terminal isocyanate groups are blocked.
15. The golf ball of claim 9 , wherein at least about 97 percent or more of the terminal isocyanate groups are blocked.