Abstract: A thermoplastic resin composition having excellent characteristics such as impact resistance and coatability is described. The thermoplastic resin composition contains a propylene based polymer and a graft copolymer having an olefin homo/co-polymer portion forming its main chain and a vinyl copolymer portion forming its branched portion. In the graft copolymer, the proportion of the olefin homo/co-polymer portion is 5 to 95% by weight, and the vinyl copolymer portion occupies the remaining weight. The vinyl copolymer portion of the graft copolymer has a hydroxyl group as a functional group. One of the olefin homo/co-polymer portion and the vinyl copolymer portion forms a dispersed phase in the other with a particle size of 0.001 to 10 .mu.m. Consequently, the graft copolymer assumes a multi-phase structure. The thermoplastic resin composition optionally further contains a thermoplastic elastomer.

Abstract: A sliding property improving agent comprising a multi-phase structure thermosplastic resin which consists of a dispersion of 5 to 95 parts by weight of a non-polar .alpha.-olefin polymer (a) and 95 to 5 parts by weight of a vinyl polymer (b), with the dispersing polymer having a particle size from 0.001 to 10 .mu.m. A thermoplastic resin containing said resinous agent exhibits excellent mechanical strength, high anti-brasion and improved sliding properties.