| 摘要 |
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.cm-3, a melt flow rate of not more than 0.20 dg.min as measured at 190° C. and at a load of 2.16 kgf, a melt flow rate of 17.0 to 70.0 dg.min-1 as measured at 190° C. and at a load of 21.6 kgf, a zero shear viscosity (eta0) of 200,000 to 2,000,000 Pa.s, a characteristic time constant (&tgr;0) of 50 to 500 sec., and a ratio (&tgr;0/eta0) of 1.0x10-4 to 4.0x10-4 Pa-1, the zero shear viscosity (eta0) being obtained by approximating a dynamic melt viscosity (eta*, unit: Pa.s) with equation [1], the dynamic melt viscosity (eta*) being obtained by measurement using a rheometer at 190° 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.s-1:
|
