Polyethylene Copolymers

摘要

A multimodal ethylene copolymer having the following properties:
i) density comprised in the range from 0.880 to 0.955 g/cm3;ii) total comonomer content ranging from 6% to 25% by weight;iii) content of 1-butene derived units ranging from 0 to 2% by weight;iv) Mw/Mn comprised from 4 to 20;v) intrinsic viscosity (decalin at 135° C. as determined according to EN ISO 1628-312003) comprised between 1.0 and 4.0 dL/g;

said multimodal ethylene copolymer comprises from 10% to 80% by weight of a first polyethylene component and being detected at the Crystaf® apparatus at a temperature higher than 75° C. and from 90% to 20% by weight of a second polyethylene component being a copolymer being detected at a Crystaf® apparatus at a temperature lower than 75° C.; wherein said multimodal ethylene copolymer being fractionated into 12 fractions by means of the Holtrup analysis, the fractions containing more than 2% by weight of the total amount of material meet the following relationship:
Cf/HDPE>−0.0075HDPE+0.58;
wherein Cf is the amount (% wt) of comonomer of formula CH2═CHT in the copolymer of the fraction and HDPE is the amount (% wt) of the homopolymer component present in the fraction.

主权项

1. A multimodal ethylene copolymer having a comonomer selected from a group consisting of derived units of alpha olefins of formula CH2═CHT wherein T is a C3-C10 alkyl group; said copolymer having the following properties:
i) a density in the range from 0.880 to 0.955 g/cm3; ii) a total comonomer content ranging from 6% to 25% by weight; iii) a content of 1-butene derived units ranging between 0.1 to 2% by weight; iv) a Mw/Mn comprised from 4 to 20; v) an intrinsic viscosity (decalin at 135° C. as determined according to EN ISO 1628-312003) comprised between 1.0 and 4.0 dL/g; said multimodal ethylene copolymer comprises from 10% to 80% by weight of a first polyethylene component and being with a CRYSTAF® apparatus at a temperature higher than 75° C. and from 90% to 20% by weight of a second polyethylene component being a copolymer comprising 5% to 40% by weight of derived units of alpha olefins of formula CH2═CHT and being detected with a CRYSTAF® apparatus at a temperature lower than 75° C.; wherein said multimodal ethylene copolymer being fractionated into 12 fractions by means of the Holtrup analysis, the fractions containing more than 2% by weight of the total amount of material meet the following relationship:
Cf/HDPE>−0.0075HDPE+0.58; wherein Cf is the amount (% wt) of comonomer of formula CH2═CHT in the copolymer of the fraction and HDPE is the amount (% wt) of any homopolymer component present in the fraction.