Enhanced ESCR bimodal rotomolding resin

A bimodal polyethylene composition having a density from 0.935 to 0.942 g/cm3, a melt index I2 determined according to ASTM D 1238 (2.16 kg 190° C.—I2) from 4.0 to 7.0 g/10 min, and I21 determined according to ASTM D 1238 (21.6 kg 190 C—I21) from 150 to 210 g/10 min, an I21/I2 from 28 to 40, a bent strip ESCR as determined by ASTM D 1693 in 100% octoxynol −9 for conditions A and B of greater than 1000 hours, a terminal vinyl unsaturation from 0.07 to 0.14 per 1000 carbon atoms, a number average molecular weight (Mn) from 11,000 to 35,000 as determined by GPC, a weight average molecular weight (Mw) from 55,000 to 82,000 as determined by GPC, a Z average molecular weight (Mz) from 140,000 to 2000,000 as determined by GPC, an overall Mw/Mn from 2.8 to 4.0, an index of Mz/Mw from 2 to 2.9 (paragraph 60) comprising from 0.1 to 8 weight % of one or more C4-8 alpha olefin comonomers as determined by FTIR which when de-convoluted into two components consists of:

• (i) from 20 to 45 weight % of a first component consisting of from 1 to 25 wt. % of one or more C4-8 alpha olefin comonomers and the balance ethylene, said component having a density as determined according to ASTM D 792 from 0.920 to 0.930 g/cm3;
• a weight average molecular weight (Mw) from 100,000 to 180,000 g/mol, a polydispersity between 2 and 3, and a degree of short chain branching from 3 to 13 per 1000 carbon atoms as determined by GPC-FTIR;
• and
• (ii) from 80 to 55 weight % of a second component comprising one or more of C4-8 alpha olefin comonomers and the balance ethylene said component having a density as determined according to ASTM D 792 from 0.945 to 0.955 g/cm3, a weight average molecular weight (Mw) from 15,000 to 70,000, a polydispersity of less than 3, and a degree of short chain branching less than 5 per 1000 carbon atoms as determined by GPC FTIR wherein in the difference in densities between components (i) and (ii) is less than 0.030 g/cm3.