Patent ID: 7037977

Claim:
A polyethylene resin comprising from 35 to 49 wt % of a first polyethylene fraction of high molecular weight and from 51 to 65 wt % of a second polyethylene fraction having a lower molecular weight than said first polyethylene fraction: (a) said first polyethylene fraction comprising a linear low density polyethylene having a density of no more than 0.928 g/cm 3 , and a high load melt index, HLMI, of less than 0.6 g/10 min; (b) said second polyethylene fraction comprising a high density polyethylene having a density of at least 0.969 g/cm 3 and a melt index, MI 2 of greater than 100 g/10 min.; and (c) said polyethylene resin having a density of greater than 0.951 g/cm 3 , a high load melt index, HMLI, within the range of 1–100 g/10 min and being effective when formed into a high strength pipe to provide such having a creep resistance measured according to ISO 1167 on a 32mm diameter SDR11 pipe of at least 500 hours at 20° C. and 13 MPa and a stress crack resistance measured according to the full notch creep test of ISO DIS 16770 of at least 500 hours measured at 80° C. and 5 MPa.