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Abstract

A polyethylene resin superior in both moldability and long-term physical properties and suitable for both pipe and pipe joint, the polyethylene resin having a density of 0.915 to 0.955 g.multidot.cm.sup.-3, a melt flow rate of not more than 0.20 dg.multidot.min as measured at 190.degree. C. and at a load of 2.16 kgf, a melt flow rate of 17.0 to 70.0 dg.multidot.min.sup.-1 as measured at 190.degree. C. and at a load of 21.6 kgf, a zero shear viscosity (.eta..sub.0) of 200,000 to 2,000,000 Pa.multidot.s, a characteristic time constant (.tau..sub.0) of 50 to 500 sec., and a ratio (.tau..sub.0 /.eta..sub.0) of 1.0.times.10.sup.-4 to 4.0.times.10.sup.-4 Pa.sup.-1, the zero shear viscosity (.eta..sub.0) being obtained by approximating a dynamic melt viscosity (.eta.*, unit: Pa.multidot.s) with equation [1], the dynamic melt viscosity (.eta.*) being obtained by measurement using a rheometer at 190.degree. C., at a parallel plate spacing of 1.5 mm, at a distortion of 10% to 15% and in the frequency (.omega.) range of 100 to 0.01 rad.multidot.s.sup.-1 : ##EQU1##

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