Polyolefin-based composite resin composition having low coefficient of linear thermal expansion

This application is based on application No 99-66381 filed in the Korean Industrial Property Office on Dec. 30, 1999, the content of which is incorporated hereinto by reference. The present invention relates to a polyolefin-based composite resin composition having a low coefficient of linear thermal expansion, wherein the composition comprises a) 40 to 80 weight % of crystalline ethylene-propylene copolymer, b) 5 to 40 weight % of ethylene-alpha-olefin copolymer, c) 5 to 30 weight % of calcium-metasilicate based wollastonite, and d) 5 to 30 weight % of inorganic reinforcing agent based on the total composition amount. The polyolefin-based composite resin composition having a low coefficient of linear thermal expansion not only has excellent mechanical rigidity, impact resistance, heat resistance, injection moldability, product flatness, and dimensional stability, but also has a low shrinkage, a low coefficient of linear thermal expansion, and a low heat sag. Therefore, it can be used for the manufacture of automobile exterior components.