Patent ID: 6953823

Claim:
An elastomeric insulating composition for a solid propellant rocket motor which comprises: (a) 50 phr to 95 phr of a solid ethylene-propylene diene terpolymer rubber; (b) 5 phr to 50 phr of a liquid ethylene-propylene diene terpolymer rubber; (c) 5 phr to 50 phr of a polyaramid fiber; (d) 1 phr to 3 phr of a sulfur; (e) 1 phr to 3 phr of a curing accelerator, said curing accelerator is selected from the group consisting of 4,4′-dithio dimorpholine and N-tert-butyl-2 -benzo thiazole sulfenamide and a mixture thereof; and (f) 1 phr to 20 phr of a zinc hydroxystannate; (g) 10 phr to 50 phr of a chlorinated flame retardant which is 1,2,3,4,7,8,9,10,13,13,14,14-dodecachloro-1,4,4a,5,6,6a,7,10,10a,-11,12,12a-dodecahydro-1,4,7,10-dimethanodibenzo(a.e)cyclooctene; (h) 20 phr to 120 phr of an inorganic filler, said inorgenic filler is selected from the group consisting of silicon dioxide, aluminum hydroxide and magnesium hydroxide and a mixture thereof; (i) 4 phr to 8 phr of a tackifier of synthetic polyterpene resin.