Unimodal polyethylene copolymer and film thereof

Patent metadata

Field	Value
Publication number	US-11649305-B2
Application number	US-201917261605-A
Country	US
Kind code	B2
Filing date	Jul 29, 2019
Priority date	Jul 31, 2018
Publication date	May 16, 2023
Grant date	May 16, 2023

Abstract

A unimodal ethylene-co-1-hexene copolymer that, when in melted form at 190 degrees Celsius, is characterized by a unique melt property space defined by combination of melt elasticity and complex viscosity ratio (shear thinning)properties. A blown film consisting essentially of the unimodal ethylene-co-1-hexene copolymer. A method of synthesizing the unimodal ethylene-co-1-hexene copolymer. A method of making the blown film. A manufactured article comprising the unimodal ethylene-co-1-hexene copolymer.

First claim

The invention claimed is:

1. A unimodal ethylene-co-1-hexene copolymer that, when in melted form at 190° C., exhibits a melt property space defined by a combination of melt elasticity and complex viscosity ratio properties, wherein the combination is defined according to equation 1 (Eq. 1): 6*SH1000+1,721<G′ (G″=3,000 Pa)<6*SH1000+1,828 (Eq. 1); wherein < is less than; * is multiplication; + is addition; G′ (G″=3,000 Pa) is melt elasticity in Pascals (Pa) measured according to Melt Storage Modulus Test Method at loss modulus G″=3000 pascals; SH1000 is a complex viscosity ratio equal to Eta*0.126/Eta*126, wherein Eta*0.126 is complex viscosity in pascal-seconds (Pa-s) measured at 0.126 radian per second (rad/s) by Dynamic Mechanical Analysis Test Method; and Eta*126 is complex viscosity in Pa-s measured at 126 rad/s by the Dynamic Mechanical Analysis Test Method; wherein the unimodal ethylene-co-1-hexene copolymer has a high load melt index (I 21 ) from 15.0 to 25.0 grams per 10 minutes (g/10 min.), measured according to ASTM D1238-13 (190° C., 21.6 kg).

2. The unimodal ethylene-co-1-hexene copolymer of claim 1 exhibiting at least one of properties (a) to (g):
(a) a density from 0.935 to 0.945 gram per cubic centimeter (g/cm 3 ) measured according to ASTM D792-13, Method B;
(b) a high load melt index (I 21 ) from 17.5 to 22.6 grams per 10 minutes (g/10 min.), measured according to ASTM D1238-13 (190° C., 21.6 kg);
(c) a melt flow ratio (MFR5 or I 21 /I 5 ) from 20.1 to 22.9, wherein I 21 is measured according to ASTM D1238-13 (190° C., 21.6 kg) and I 5 is melt index in g/10 min. measured according to ASTM D1238-13 (190° C., 5.0 kg);
(d) a molecular mass dispersity (M w /M n ), Ð M , from 28.9 to 38.7, wherein M w and M n are measured according to the GPC Test Method;
(e) wherein the combination of melt elasticity and complex viscosity ratio (shear thinning) properties is defined according to equation 1a (Eq. 1a): Eq. 1a: 6*SH1000+1,726<G′ (G″=3,000 Pa)<6*SH1000+1,824 (Eq. 1a);
(f) a complex viscosity Eta*126 from 1225 to 1345 pascal-seconds (Pa-s) measured at 126 radians per second by Dynamic Mechanical Analysis Test Method; and
(g) a complex viscosity ratio SH1000 from 33.6 to 44.0, wherein SH1000 is the ratio of complex viscosity measured at 0.126 radian per second (Eta*0.126) to the Eta*126.

3. The unimodal ethylene-co-1-hexene copolymer of claim 2 further defined by any one of limitations (i) to (xi): (i) properties (a) and (b); (ii) properties (a) and (c); (iii) properties (a) and (d); (iv) properties (a) and (e); (v) properties (a) and (f); (vi) properties (a) and (g); (vii) properties (a), (b), and (c); (viii) properties (a), (b), and (d); (ix) properties (f) and (g); (x) any six of properties (a) to (g); and (xi) each of properties (a) to (g).

4. The unimodal ethylene-co-1-hexene copolymer of claim 1 further exhibiting any one of properties (h) to (i), or a combination of properties (h) and (i): (h) a weight-average molecular weight (M w ) from 200,000.0 to 300,000.0 grams per mole (g/mol) measured according to the Gel Permeation Chromatography (GPC) Test Method; and (i) a number-average molecular weight (M n ) from 7,600.0 to 10,000.0 g/mol measured according to the GPC Test Method.

5. A method of synthesizing the unimodal ethylene-co-1-hexene copolymer of claim 1 , the method consisting essentially of contacting ethylene and 1-hexene (“C 6 ”) with a single catalyst system consisting of a unimodal chromium catalyst system in a single fluidized bed, gas-phase polymerization (FB-GPP) reactor under effective operating conditions comprising a reactor bed temperature (RBT), an average polymer residence time (avgPRT), and an ethylene partial pressure (C2P) and receiving an ethylene (C 2 ) feed, a comonomer (1-hexene or “C 6 ”) feed, a hydrogen (H 2 ) feed, and, optionally, an oxygen (O 2 ) feed wherein the feeds are characterized by a H 2 /C 2 gas molar ratio (H 2 /C 2 ), a comonomer/ethylene gas molar ratio (“C 6 /C 2 ”), and a O 2 /C 2 gas volume ratio (“[O 2 /C 2 ]”, vol/vol in ppmv); wherein RBT is from 104.0° to 110.0° C.; avgPRT is from 1.70 to 3.10 hours, C2P is from 1,100 to 1,900 kilopascals (kPa); H 2 /C 2 gas molar ratio is from 0.05 to 0.150; C 6 /C 2 gas molar ratio is from 0.010 to 0.021; and O 2 /C 2 gas volume ratio is from >0 to 130 parts per billion volume/volume (ppbv); thereby synthesizing the unimodal ethylene-co hexene copolymer in the FB-GPP reactor.

6. The method of claim 5 further comprising removing the unimodal ethylene-co-1-hexene copolymer from the FB-GPP reactor to give a removed unimodal ethylene-co-1-hexene copolymer.

7. A manufactured article comprising the unimodal ethylene-co-1-hexene copolymer of claim 1 .

8. A film consisting essentially of the unimodal ethylene-co-1-hexene copolymer of claim 1 .

9. A method of making a blown film, the method comprising melting the unimodal ethylene-co-1-hexene copolymer of claim 1 so as to give a melt thereof, extruding the melt through a die configured for forming a bubble so as to make a bubble of the unimodal ethylene-co-1-hexene copolymer, and blowing the bubble with a film-blowing machine, thereby making the blown film.

10. A blown film made by the method of claim 9 and consisting essentially of the unimodal ethylene-co-1-hexene copolymer of claim 1 .

Assignees

• Univation Tech Llc

Inventors

• Liu Bo
• Zhang Yi
• Bafna Ayush A
• Alexandre François
• Reib Robert N

Classifications

• C08F2500/39

  Tensile storage modulus E'; Shear storage modulus G'; Tensile loss modulus E''; Shear loss modulus G''; Tensile complex modulus E*; Shear complex modulus G* · CPC title

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• C08F2/34

  Polymerisation in gaseous state · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08F2500/04

  Broad molecular weight distribution, i.e. Mw/Mn > 6 · CPC title