| abstract |
The invention provides a substantially uniformly blended, flame retardant polypropylene composition and an extruded polypropylene sheet which comprises a polypropylene polymer, the bis(2,3-dibromopropylether) of tetrabromobisphenol A, antimony trioxide, titanium dioxide, calcium sulfate and distearyl pentaerythritol diphosphite. The invention further provides a method for producing such a polypropylene sheet material by forming a substantially uniform physical blend of the above components; drying the blend; heating the blend at a temperature above its melting point to form a melt of the blend components while mixing the melt; and extruding the blend through a sheet forming die and highly polished rollers. |