Patent ID: 6491984
Filing Date: 2002-12-10
Classification: C08L

Abstract:
Process for coating metallic surfaces comprising the flame-gun spraying of a polyolefin composition consisting essentially of (percentages by weight):1) from 1% to 40% of hollow microspheres; 2) from 60% to 99% of a polyolefin composition consisting essentially of (percentages by weight): a) from 25% to 95% of polypropylene homopolymer, polyethylene homopolymer, or a propylene/ethylene, propylene/C4-C10 &agr;-olefin, or propylene/ethylene/C4-C10 &agr;-olefin crystalline random copolymer, or mixtures thereof; b) from 0% to 70% of an ethylene-propylene or ethylene/C4-C10 &agr;-olefin elastomeric copolymer, optionally containing minor quantities of a diene; c) from 0.5% to 10% of polypropylene or polyethylene modified with polar groups in quantities ranging from 0.1% to 10%; d) from 0% to 10% of titanium dioxide; e) from 0% to 1.5% of an organic phosphite or phosphonite or mixtures thereof; f) from 0.8% to 2% of a thioester or an organic polysulfide or mixtures thereof; and g) from 0.45% to 1% of a phenolic stabilizer, the f/g weight ratio ranging from 0.8 to 4.5; said polyolefin composition 2) having Melt Flow Rate (â€œMFRâ€ ) (ASTM D-1238, condition L) from 2 to 150 g/10 min., having oxidation induction time values, measured at 220Â° C. and at an oxygen pressure of about 1200 mbar, greater or equal to 25 minutes, and being in powder form with not more than 3% of the granules having a diameter greater than 600 micrometers, and wherein said microspheres have not been treated with a polyolefin chain degradation agent prior to contact with said polyolefin composition, on the above mentioned surfaces.