Polyethylene copolymers having a particular comonomer distribution

Patent metadata

Field	Value
Publication number	US-10494462-B2
Application number	US-201615568662-A
Country	US
Kind code	B2
Filing date	Apr 21, 2016
Priority date	Apr 23, 2015
Publication date	Dec 3, 2019
Grant date	Dec 3, 2019

Abstract

Novel polyethylene copolymers having a relatively high comonomer partitioning tendency are disclosed as are methods for their preparation. The comonomer partitioning tendency is the tendency for a copolymer to have comonomer in the higher molecular weight chains. Novel metrics for describing the comonomer partitioning tendency are also disclosed.

First claim

What is claimed is:

1. A polyethylene copolymer, wherein the copolymer has a comonomer partitioning tendency (ζ) of greater than 1.4, wherein the copolymer has a melt index ratio (flow index (I 21 ) as measured in accordance with ASTM D1238/melt index (I 2 ) as measured in accordance with ASTM D1238) ranging from about 15 to about 50, and wherein the comonomer partitioning tendency is defined by equation (1) and measures a proclivity of the polyethylene copolymer to have comonomer in high molecular weight chains;

ξ
=

C
⁢

⁢
P
⁢

⁢
I

P
⁢

⁢
D
⁢

⁢
I
×
C
⁢

⁢
D
⁢

⁢
I

(
1
)

wherein
CPI is a comonomer partitioning index (χ w /χ n ) wherein χ w =ΣN i (M i C i ) 2 /ΣN i (M i C i ) and χ n =ΣN i (M i C i )/ΣN i ;
PDI is a polydispersity index (M w /M n );
CDI is a comonomer dispersity index (C w+1 /C w ) wherein C w =ΣN i M i C i /ΣN i M i and C w+1 =ΣN i M i C i 2 /ΣN i M i C i ;
M i =molecular weight of a copolymer;
N i =number of copolymers having molecular weight M i ;
C i =weight fraction of comonomer in a copolymer;
M w =weight average molecular weight of the copolymer;
M n =number average molecular weight of the copolymer; and
C w =average weight fraction of comonomer in the copolymer.

2. A copolymer according to claim 1 , wherein the comonomer is one or more comonomers containing 3 to 16 carbon atoms.

3. A copolymer according to claim 1 , wherein the copolymer has a melt index (I 2 ) ranging from about 0.2 to about 20.

4. A copolymer according to claim 1 , wherein the copolymer has a density ranging from about 0.87 g/cm 3 to about 0.97 g/cm 3 .

5. A copolymer according to claim 1 , wherein the copolymer has a polydispersity index (M w /M n ) ranging from about 1.5 to about 20.

Assignees

• Univation Tech Llc

Inventors

• Kuhlman Roger L

Classifications

• C08F4/65927

  two cyclopentadienyl rings being mutually bridged · CPC title

• C08F2/04

  Polymerisation in solution (C08F2/32 takes precedence) · CPC title

• C08F210/02 Primary

  Ethene · CPC title

• C08F2/34

  Polymerisation in gaseous state · CPC title

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title