POLYOLEFIN COMPOSITIONS FOR BUILDING MATERIALS

Polyolefin compositions useful for construction articles for outdoor use, for instance house siding, cladding, soffit or roofing. The compositions comprise a polyolefin substrate which has incorporated therein one or more additives selected from the group consisting of a) one or more ultraviolet light absorbers, b) one or more hindered amine light stabilizers and c) one or more antioxidants. Advantageously, the polyolefin substrate also has incorporated therein d) one or more colorants, e) one or more fillers, f) one or more flame retardants and optionally g) one or more antimicrobial compounds. The compositions exhibit certain performance levels according to standard tests, for example impact strength of >35 in-lb per ASTM D4226, coefficient of linear thermal expansion of