Metallocene-catalyzed polyethylene

Patent metadata

Field	Value
Publication number	US-10053522-B2
Application number	US-201214131397-A
Country	US
Kind code	B2
Filing date	Jul 6, 2012
Priority date	Jul 8, 2011
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

wherein the composition distribution breadth index (CDBI) of the polyethylene resin is below 70%, as analyzed by quench TREF (temperature rising elution fractionation) analysis.

First claim

The invention claimed is:

1. A metallocene-catalyzed polyethylene resin having a multimodal molecular weight distribution, comprising:
from 45% by weight to 75% by weight of a low density fraction, said low density fraction having a density below or equal to 0.918 g/cm 3 as measured following the method of standard test ISO 1183 at a temperature of 23° C.;
wherein the density of the polyethylene resin is from 0.920 to 0.945 g/cm 3 ;
wherein the Mw/Mn of the polyethylene resin is from 2.8 to 6;
wherein the melt index MI 2 of the polyethylene resin is from 0.1 to 5 g/10 min as measured following the method of standard test ISO 1133 Condition D at a temperature of 190° C. and under a load of 2.16 kg;
wherein the composition distribution breadth index (CDBI) of the polyethylene resin is below 70%, as analyzed by quench TREF (temperature rising elution fractionation) analysis; and wherein the polyethylene resin comprises a bimodal composition as measured by quench TREF analysis,
wherein the polyethylene resin has a g rheo of less than 0.90 and greater than 0.35, wherein g rheo is determined according to:

g
rheo

⁡

(
PE
)

=

M
w

⁡

(
SEC
)

M
w

⁡

(

η
0

,
MWD
,
SCB

)

wherein M w (SEC) is the weight average molecular weight obtained from size exclusion chromatography expressed in kDa, and wherein M w (n 0 ,MWD,SCB) is determined according to the following
M w (η 0 ,MWD,SCB )=exp(1.7789+0.199769Ln M n +0.209026(Lnη 0 )+0.955(ln ρ)−0.007561(Ln M z (Lnη 0 )+0.02355(ln M z ) 2

wherein density ρ is measured in g/cm 3 and measured according to ISO 1183 at a temperature of 23° C. and wherein zero shear viscosity η 0 in Pa·s is obtained from a frequency sweep experiment combined with a creep experiment, and taking the assumption of equivalence of angular frequency (rad/s) and shear rate, and wherein zero shear viscosity η 0 is estimated by fitting with Carreau-Yasuda flow curve (η−W) at a temperature of 190° C., obtained by oscillatory shear rheology on ARES-G2 equipment in the linear viscoelasticity domain, and wherein circular frequency (W in rad/s) varies from 0.05-0.1 rad/s to 250-500 rad/s, and the shear strain is typically 10%, and wherein the creep experiment is carried out at a temperature of 190° C. under nitrogen atmosphere with a stress level such that after 1200 s the total strain is less than 20%.

2. The metallocene-catalyzed polyethylene resin according to claim 1 , wherein the Mw of the low density fraction is from 80 to 140 kDa.

3. The metallocene-catalyzed polyethylene resin according to claim 1 , wherein the CDBI of the polyethylene resin is in a range of 30-50%, as analyzed by quench TREF analysis.

4. The metallocene-catalyzed polyethylene resin according to claim 1 , wherein the polyethylene resin comprises a higher density fraction having a higher density than the low density fraction, wherein a ratio Mw of the low density fraction/Mw of the higher density fraction is less than 6 and greater than 2.5.

Assignees

• Vantomme Aurelien
• Bernard Pierre
• Michel Jacques
• Willocq Christopher
• Sigwald Armelle
• Total Res & Technology Feluy

Inventors

• Vantomme Aurélien
• Bernard Pierre
• Michel Jacques
• Willocq Christopher
• Sigwald Armelle

Classifications

• C08L23/0807 Primary

  with unsaturated hydrocarbons only containing four or more carbon atoms · CPC title

• C08J2323/04

  Homopolymers or copolymers of ethene · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title