CA2835740C

Ethylene copolymer compositions, film and polymerization processes

Abstract

Ethylene copolymers having a relatively high melt flow ratio and a multimodal profile in a temperature rising elution fractionation (TREF) plot are disclosed. The copolymers can be made into film having good dart impact values and good stiffness properties under decreased extruder pressures.

CA2835740C, drawing sheet 1
Sheet 1 of 16

Term

7.2 yearsleft in the term

Expires 4 December 2033.

  1. Priority
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  3. Granted
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  5. Expires

22 claims: 3 independent, 19 dependent

  1. 1
    The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:1. An ethylene copolymer comprising ethylene and an alpha olefin having 3-8 carbon atoms, the ethylene copolymer having a density of from 0.916 g/cm 3 to 0.936 g/cm 3 , a melt index (h) of from 0.1 g/10min to 2.0 g/10min, a melt flow ratio (I21/I2) of from 32 to 50, a molecular weight distribution (Mw/Mn) of from 3.6 to 6.5, a reverse comonomer distribution profile as determined by GPC-FTIR, a multimodal TREF profile, and a composition distribution breadth index CDBI50 of from 45 wt% to 75 wt% as determined by TREF, and which further satisfies the relationship: (Mw/Mn) £ 72 [(I21/I2) 1 + 10- 6 (Mn)].
  2. 11
    An olefin polymerization process to produce an ethylene copolymer, the process comprising contacting ethylene and at least one alpha olefin having from 3-8 carbon atoms with a polymerization catalyst system in a single gas phase reactor; the ethylene copolymer having a density of from 0.916 g/cm 3 to 0.936 g/cm 3 , a melt index (h) of from CA 2835740 2020-01-22 119 0.1 g/10min to 2.0 g/10min, a melt flow ratio (I21/I2) of from 32 to 50, a molecular weight distribution (Mw/Mn) of from 3.6 to 6.5, a reverse comonomer distribution profile as determined by GPC-FTIR, a multimodal TREF profile, a composition distribution breadth index CDBI50 of from 50 wt% to 75 wt% as determined by TREF and which satisfies the following relationship:(Mw/Mn) 72 [(I21/I2)· 1 + 10 -6 (Mn)];wherein the polymerization catalyst system comprises a single transition metal catalyst, a support, a catalyst activator, and a catalyst modifier;and wherein the single transition metal catalyst is a group 4 organotransition metal catalyst.
  3. 18
    A film layer having a dart impact of greater than 200 g/mil, a 1 % MD secant modulus of greater than 140 MPa, a 1% TD secant modulus of greater than 175 MPa and a ratio of MD tear to TD tear of 0.75 or less, wherein the film layer comprises an ethylene copolymer having a density of from 0.916 g/cm 3 to 0.930 g/cm 3 , a melt index (I2) of from 0.1 g/10min to 2.0 g/10min, a melt flow ratio (I21/I2) of from 32 to 50, a molecular weight distribution (Mw/Mn) of from 3.6 to 6.5, a reverse comonomer distribution profile as determined by GPC-FTIR, a multimodal TREF profile, a composition distribution breadth index CDBI50 of from 50 wt% to 75 wt% as determined by TREF, and which satisfies the following relationship:(Mw/Mn) £ 72 [(I21/I2) 1 + 10^ (Mn)]. CA 2835740 2020-01-22 121