Patent ID: 6057017
Filing Date: 2000-05-02
Classification: B32B,F16L,Y10T

Abstract:
A polyolefin-coated steel pipe comprising a steel pipe having an external surface coated with an epoxy primer layer, a maleic anhydride-modified polyolefin layer and a polyolefin layer lying one upon another in that order, wherein the maleic anhydride-modified polyolefin layer contains compounds A to C, and the polyolefin layer contains compounds A to E:A: 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene;B: at least one compound selected from the group consisting of tetrakis{[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionyloxy]methyl}methan e, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-isocyanuric acid, and 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dime thylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane;C: pentaerythritol tetrakis(3-laurylthiopropionate);D: at least one selected from the group consisting of 2,4-di-tert-butylphenyl 3',5'-di-tert-butyl-4'-hydroxybenzoate, 4-tert-octylphenyl salicylate, 2-(2'-hydroxy-5'-methylphenyl)-benzotriazole, 2-(3-,5'-di-tert-butyl-2'-hydroxyphenyl)-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzo triazole and 2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole; andE: rutile type titanium dioxide.