Polyolefin compositions
Ethylene copolymers valuable for films, coatings, sheets, and molded articles are disclosed. Some of the copolymers have a long-chain-branching index from 0.25 to 0.60 and a gpcBR index from 0.1 to 0.7. Others have a primary DSC melting point that is less than its secondary DSC melting point. Also disclosed is LLDPE in which the weight percentage of the low-temperature elution fraction exceeds that of the high-temperature fraction, and wherein the M w of the low-temperature fraction exceeds that of the high-temperature fraction. The ethylene copolymers process easily, even at low melt indices, and films from the copolymers have high stiffness, good impact resistance, and high heat-seal strength over a wide temperature range.
1. An ethylene copolymer having a density from 0.90 to 0.94 g/cm 3 , a melt index from 0.5 to 3 g/10 min, a long-chain-branching index from 0.25 to 0.60, and a gpcBR index within the range of 0.12 to 0.20.
2. The copolymer of claim 1 having primary and secondary DSC melting points corresponding to the peak melting temperature of, respectively, major and minor sample fractions; wherein the primary DSC melting point is less than the secondary DSC melting point.
3. The copolymer of claim 1 prepared using a bridged indeno[2,1-b]indolyl Group 3-10 metal complex.
4. A film produced from the ethylene copolymer of claim 1 .
5. An ethylene copolymer having a density from 0.90 to 0.94 g/cm 3 , a melt index from 0.5 to 3 g/10 min, and primary and secondary DSC melting points corresponding to the peak melting temperature of, respectively, major and minor sample fractions; wherein the primary DSC melting point is less than the secondary DSC melting point; said copolymer having a phase angle less than 70° at complex modulus, G*=2×10 4 dynes/cm 2 and at least 50° at G*=1×10 6 dynes/cm 2 .
6. A film produced from the ethylene copolymer of claim 5 .
7. An ethylene copolymer having a density from 0.90 to 0.94 g/cm 3 and a melt index from 0.5 to 3 g/10 min, wherein the copolymer comprises, by 3D-TREF analysis, at least 80 wt.% of a polymer component having a weight average molecular weight, M w , from 100,000 to 130,000 and an elution temperature range from 40° C. to 85° C.
8. The copolymer of claim 7 having a complex viscosity, η*, at 0.1 rad/sec in the range of 1.0×10 5 to 2.5×10 5 poise and η* at 100 rad/sec in the range of 1.1×10 4 to 1.7×10 4 poise.
9. The copolymer of claim 7 having a phase angle, δ, less than 70° at complex modulus, G*=2×10 4 dynes/cm 2 and at least 50° at G*=1×10 6 dynes/cm 2 .
10. The copolymer of claim 7 prepared using a bridged indeno[2,1-b]indolyl Group 3-10 metal complex.
11. A film produced from the ethylene copolymer of claim 7 .