POLYPROPYLENE-COATED STEEL PIPE WITH GOOD HEAT-OXIDATION DETERIORATION RESISTIVITY AND WEATHERABILITY, AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To form a polyethylene-coated steel pipe consistently having a heat- oxidation deterioration resistivity and weatherability of the polypropylene-coated steel pipe by finding out a prescription of an antioxidant and light stabilizer without danger of destroying anti-oxidation deterioration properties of polypropylene. SOLUTION: The polypropylene-coated steel pipe has an epoxy primer layer, a maleic anhydride modified polypropylene layer, and a polypropylene layer laminated in turn on the circumferential face of the steel plate, and the maleic anhydride modified polypropylene layer and polypropylene layer consists of ethylene-propylene block copolymer. In addition, a predetermined quantity of an antioxidant and light stabilizer, and an organic pigment are blended in the propylene layer respectively.