STRETCHED POLYETHYLENE PIPE EXCELLENT IN ENVIRONMENTAL STRESS CRACKING RESISTANCE

摘要

PROBLEM TO BE SOLVED: To enhance environmental stress cracking resistance by using a precursor containing polyethylene as a raw material. SOLUTION: A stretched polyethylene pipe is produced by using a Ziegler- Natta catalyst consisting of a solid catalyst component containing Mg, Ti and halogen as essential components and an organoaluminum compd. and satisfies respective conditions of (A) a ratio (Mw/Mn) of a wt. average mol.wt. (Mw) and a number average mol.wt. (Mn) of 8 or more, (B) a melt flow rate(MFR) of 0.01-1 g/10 min, (C) a density (ρ) of 0.940 g/cm3 or more and (D)ρ<=-2.171×103×log(MFR)+0.950.