Development of flame and smoke retardant thermoplastic molding compounds

Compositions of polypropylene and ethylene-acrylic acid resins filled with high levels of alumina trihydrate of magnesium hydroxide were examined for smoke generation and impact resistance. Best results were obtained using alumina trihydrate coated with a low modulus elastomer, and ethylene-acrylic acid resin. Addition of polyvinyl alcohol fibers to the filled resin improves impact resistance and causes somewhat of an increase in smoke evolution.