Thermosetting compositions for injection molding

Claim 1

A process for preparing a thermoset injection molded product having a hot tensile strength of at least 250 pounds per square inch when measured according to ASTM D412-64T at the mold temperature employed in said process, which process comprises the steps of: injecting a vulcanizable composition into a preheated mold, said mold having been preheated to a temperature sufficient to crosslink said vulcanizable composition within five minutes, said composition consisting essentially of about 35 to about 75 parts by weight of (A) an ethylene-vinyl acetate copolymer containing about 7 to about 55 weight percent of vinyl acetate based on the total weight of said copolymer; about 65 to about 25 parts by weight of (B) a clay filler selected from the class consisting of an organosilane treated clay and an organopolyester treated clay wherein said organopolyester is reaction product of polyfunctional organic carboxylic acid and/or polyfunctional organic carboxylic acid anhydride with polyhydric alcohol; the sum of (A)+(B) being about 100 parts by weight in the composition; about 1 to about 5 parts by weight based on the sum of (A)+(B) of (C) an organic peroxide crosslinking agent having a half-life at its stock temperature of greater than one hour; and 0 to about 5 parts by weight based on the sum of (A)+(B) of (D) of an organic crosslinking booster; wherein said components (A), (B), (C) and (D) are such that a crosslinked product obtained upon crosslinking an admixture containing only said components (A), (B), (C) and (D) in the same proportions as (A), (B), (C) and (D) are present in said vulcanizable composition, has a hot tensile strength of at least 250 pounds per square inch when measured according to ASTM D412-64T at the same temperature employed to crosslink said admixture; crosslinking said composition in said mold, and recovering the thermoset injected molded product by removing it from said mold.