Cross-linked thermoplastic polyurethane/polyurea and method of making same

Abstract

A process for forming a cross-linked thermoplastic polymer is disclosed herein. The cross-linked thermoplastic polymer is formed by heating a first mixture containing a thermoplastic urethane base material, a monomeric diisocyanate comprising between 1 to 10% of the total weight of the first mixture, and a second mixture of a first diamine and a second diamine comprising between 1 to 10% of the total weight of a total reaction product. The heated first mixture, which is flowable, is injected into at least one injection molding device, with the second mixture injected at predetermined intervals to create a homogeneous reaction product.

1 . An apparatus for forming a golf ball layer composed of a cross-linked thermoplastic polymer, the apparatus comprising:
 a hopper for mixing a thermoplastic urethane based material and a monomeric diisocyanate to create a first mixture, the monomeric diisocynate comprising between 1% to 10% of the total mass of the first mixture, wherein the first mixture is heated within the hopper to a temperature within the range of 250° F. to 550° F. to create a heated first mixture;   a mixing chamber for mixing 4,4′ methylene-bis-(3-chloro-2,6-diethylaniline) and diethyl 2,4-toluenediamine to create a second mixture, wherein the 4,4′ methylene-bis-(3-chloro-2,6-diethylaniline) is 75% to 95% of the total mass of the second mixture and diethyl 2,4-toluenediamine is 25% to 5% of the total mass of the second mixture, wherein the second mixture is heated to a temperature greater than the melting point of the second mixture and less than 225° F. to create a liquid second mixture having a volume;   a barrel having a first opening in flow communication with the hopper for receiving the heated first mixture, the barrel in flow communication with the mixing chamber for receiving injections of the liquid second mixture into the barrel in a plurality of dispensing shots of approximately equal amounts of the volume of the liquid second mixture during a predetermined time period;   at least one injection mold cavity in flow communication with the barrel to receive the reaction product formed by the reaction of the heated first mixture and the liquid second mixture and to form a golf ball layer composed of the reaction product.