SE7712678L - VULLABLE MOLDING COMPOSITION AND PROCEDURE - Google Patents

Abstract

A vulcanizable composition suitable for thermoset injection molding 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; he 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. The invention is believed to represent the first thermosetting, injection moldable composition based on ethylene-vinyl acetate copolymers. It differs from prior art compositions primarily in that a specific copolymer containing specific amounts of comonomers polymerized therein are required, and that clay treated with silane or organopolyester is required. Also, the peroxide must halve specific properties described above.