Polyolefin compositions
Embodiments are directed towards polyolefin compositions including a high molecular weight polyolefin and a low molecular weight polyolefin.
1 . A polyethylene composition comprising:
a first polyethylene having a density from 0.920 to 0.945 g/cm 3 wherein the first polyethylene is an ethylene/1-hexene copolymer that has a high load melt index (I 21 ) from 0.45 to 1.50 g/10 min.; and
a second polyethylene having an I 2 from 5 to 200 g/10 min,
wherein the polyethylene composition has a first polyethylene split of from 39 to 49 weight percent and a cumulative detector fraction (CDF LS ) at a molecular weight of ≥10,000,000 g/mol of greater than 0.085, further wherein the polyethylene composition exhibits one or more of:
(i) an absolute Z-average molecular weight (M z (Abs)) from 3,500,000 to 12,000,000 g/mol; or
(ii) an absolute weight average molecular weight (M w (Abs)) from 350,000 to 800,000 g/mol.
2 . The polyethylene composition of claim 1 , wherein the second polyethylene is a polyethylene homopolymer.
3 . The polyethylene composition of claim 1 , wherein the polyethylene composition provides an Environmental Stress Crack Resistance F 50 Condition B (10% IGEPAL) greater than 140 hours.
4 . The polyethylene composition of claim 1 , wherein the polyethylene composition provides a swell (t1000) greater than 6.5 seconds.
5 . The polyethylene composition of claim 1 ,
wherein the polyethylene composition has a density from 0.930 to 0.970 g/cm 3, a M w /M n greater than 17, a melt index (I 21 ) from 15 to 40 g/10 min, and
provides a G′/G″ (0.02 s −1 ) value that is greater than 0.3087+0.00404*(Eta at 0.02 s −1 )/(Eta at 200 s −1 )−0.224* first polyethylene Split, and
a G′(G″=3000 Pa) value from 1650 to 1870 Pa.
6 . The polyethylene composition of claim 1 , wherein the polyethylene composition provides a melt strength from 6.5 to 12.0 cN.
7 . The polyethylene composition of claim 1 , wherein the polyethylene composition has a weight Z-average molecular weight (M z ) from 1,500,000 to 5,500,000 g/mol.
8 . The polyethylene composition of claim 1 , having one or more of the following limitations:
(ii) wherein the first polyethylene has a density from 0.937 to 0.941 g/cm 3; and
(iii) wherein the second polyethylene has a melt index (I 2 ) from 16.5 to 129 g/10 min.
9 . A method of making the polyethylene composition of claim 1 , the method comprising polymerizing with a Ziegler-Natta catalyst ethylene and 1-hexene in a first fluidized bed reactor under first process conditions to make the first polyethylene containing the olefin polymerization catalyst, transferring the first polyethylene containing the olefin polymerization catalyst to a second fluidized bed reactor, which is in-series with the first fluidized bed reactor, and polymerizing ethylene in the second fluidized bed reactor under second process conditions so as to make the second polyethylene, wherein the first process conditions in the first fluidized bed reactor are configured for making the first polyethylene and the second process conditions in the second fluidized bed reactor are configured for making the second polyethylene, thereby making the polyethylene composition.