A composition comprising, by weight:
- (1) 100 parts of a thermoplastic olefin comprising an olefin polymer having an isotactic index of at least 80 and an olefin polymer rubber, the thermoplastic olefin having a rubber content of at least 20%;
- (2) about 5 to about 20 parts per hundred parts of the thermoplastic olefin of a propylene homopolymer or propylene copolymer with ethylene or a 4-8 C alpha-olefin having an ethylene or alpha-olefin content of about 0.5% to about 20%, grafted with an anhydride of an aliphatic .alpha., .beta.-unsaturated dicarboxylic acid and having an anhydride content of about 2% to about 5%;
- (3) about 3 to about 20 parts per hundred parts of the thermoplastic olefin of an oxidized polyethylene wax having a melting point of less than 116.degree. C. and an acid number of less than 40;
- (4) a functionalized polymer that is reactive with the anhydride groups of the grafted polymers, selected from the group consisting of:
- (a) about 2 to about 6 parts per hundred parts of the thermoplastic olefin of an amine-terminated polyalkylene glycol;
- (b) about 2 to about 6 parts per hundred parts of the thermoplastic olefin of a hydroxy-terminated polyolefin,
- (c) about 2 to about 6 parts per hundred parts of the thermoplastic olefin of a hydroxy-terminated polybutadiene;
- (d) about 2 to about 8 parts per hundred parts of the thermoplastic olefin of a hydroxy-terminated olefin/alkylene oxide copolymer;
- (e) about 2 to about 8 parts per hundred parts of the thermoplastic olefin of a hydroxy-terminated polyalkylene oxide,
- (f) about 2 to about 8 parts per hundred parts of the thermoplastic olefin of a methoxy-terminated polyalkylene oxide,
- (g) about 2 to about 8 parts per hundred parts of the thermoplastic olefin of an amine-terminated olefin/alkylene oxide copolymer, and
- (h) mixtures thereof;
- (5) optionally, about 5 to about 30 parts per hundred parts of the thermoplastic olefin of a polyolefin rubber grafted with an anhydride of an aliphatic .alpha., .beta.-unsaturated dicarboxylic acid, having an anhydride content of at least 0.3% but less than 3% and comprising a polymer of ethylene and a 3-8 C alpha-olefin, optionally containing about 0.5% to about 10% of a diene, which contains about 30% to about 70% ethylene;
- and
- (6) optionally about 5 to about 20 parts per hundred parts of the thermoplastic olefin of an ethylene polymer grafted with an anhydride of an aliphatic .alpha., .beta.-unsaturated dicarboxylic acid, having an anhydride content of about 1% to about 16% and a molecular weight M.sub.n of about 500 to about 5000, provided that at least 5 parts of anhydride-grafted polypropylene or propylene copolymer and 3 parts of oxidized polyethylene wax per hundred parts of the thermoplastic olefin are also present.