LDPE enabling high output and good optics when blended with other polymers

Patent metadata

Field	Value
Publication number	US-9243087-B2
Application number	US-48251709-A
Country	US
Kind code	B2
Filing date	Jun 11, 2009
Priority date	Jun 11, 2009
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

An ethylene-based polymer characterized as having a density from about 0.9 to about 0.94 grams per cubic centimeter, a molecular weight distribution (M w /M n ) from about 8 to about 30, a melt index (I 2 ) from about 0.1 to about 50 grams per 10 minutes, a gpcBR value greater than 1.4 as determined by a gpcBR Branching Index and a Y value less than about 2 is disclosed. This ethylene-based polymer is especially useful for blending with other polymers such as LLDPE. When converting the blends into film, especially blown film, bubble stability and output is increased.

First claim

What is claimed is:

1. A low density polyethylene (LDPE) characterized as having a density from about 0.9 to about 0.94 grams per cubic centimeter, a molecular weight distribution (M w /M n ) from about 8 to about 12, a melt index (I 2 ) greater than 0.5 and less than 2 g/10 minutes, a gpcBR value from about 1.4 to about 10 as determined by a gpcBR Branching Index, and a GPC-LS characterization Y value less than 1.2; and
wherein the polymer is prepared in a reactor configuration comprising a tubular reactor comprising multiple reaction zones, and wherein each reaction zone receives a peroxide injection, and wherein the peak temperature in each reaction zone is from 305° C. to 310° C.; and wherein the Y value is calculated from the following equations:
Y =Log(LSCDF)+3.5
LSCDF=Abs( A/B *SF),
SF=A Slope Function=Abs( x )+0.1,

wherein A=A1+A2, wherein A1 is the area bound between a straight line drawn between two logarithmic cc-GPC molecular weights at 350,000 g/mole and 1,320,000 g/mole, and the concentration-normalized LS concentration curve, where the concentration-normalized LS response value of the straight line is greater than the concentration-normalized LS response value for the concentration-normalized LS chromatogram curve between the two logarithmic cc-GPC molecular weights;
A2 is the area bound between a straight line drawn between two logarithmic cc-GPC molecular weights at 350,000 g/mole and 1,320,000 g/mole, and the concentration-normalized LS concentration curve, wherein the concentration-normalized LS response value of the straight line is less than the concentration-normalized LS response value for the concentration-normalized LS chromatogram curve between the two logarithmic cc-GPC molecular weights;
B is the area under the concentration-normalized LS chromatogram curve between the two logarithmic cc-GPC molecular weight values;

wherein the value of “x” is defined as follows:

x
=

LSresponse

(

Point
⁢

⁢
2

,
CN

)

-

LSresponse

(

Point
⁢

⁢
2

,
CN

)

LSresponse

(

Point
⁢

⁢
2

,
CN

)

log
⁢

⁢

MW

(

Point
⁢

⁢
2

,
ccGPC

)

-

log
⁢

⁢

MW

(

Point
⁢

⁢
1

,
ccGPC

)

;

wherein the “log MW” terms are the above logarithmic cc-GPC molecular weights for Points 1 and 2, respectively, and the “LS response” terms are the concentration-normalized LS response values for Points 1 and 2, respectively.

2. A composition comprising the polymer of claim 1 and at least one other natural or synthetic polymer.

3. The composition of claim 2 wherein the synthetic polymer is selected from the group consisting of linear low density polyethylene (LLDPE), high density polyethylene (HDPE), and a low density polyethylene (LDPE).

4. The composition of claim 2 wherein the synthetic polymer comprises LLDPE.

5. The composition of claim 4 wherein the LLDPE comprises at least 50 percent or greater, by weight of the composition.

6. At least one film layer comprising the composition of claim 3 .

7. The polymer of claim 1 , wherein the polymer has a GPC Mw and a zero shear viscosity (η o )(Pa*s) relationship
log(η o (Pa*s))>3.6607*log(GPC Mw)−14.678.

8. The polymer of claim 1 , wherein the polymer has a melt strength at 190° C. in cN of greater than 11.5 cN.

9. A film comprising at least one film layer comprising the polymer of claim 1 .

10. The film layer according to claim 9 , wherein the film layer has a machine direction (MD) shrink tension greater than 15 psi.

11. The polymer of claim 1 , wherein the LDPE polymer has a molecular weight distribution from 8.43 to 8.72.

12. A low density polyethylene (LDPE) characterized as having a density from about 0.9 to about 0.94 grams per cubic centimeter, a molecular weight distribution (M w /M n ) from about 8 to about 12, a melt index (I 2 ) greater than 0.5 and less than 2 g/10 minutes, a gpcBR value from about 1.4 to about 10 as determined by a gpcBR Branching Index, and a GPC-LS characte

Assignees

• Karjala Teresa P
• Savargaonkar Nilesh R
• Ortega Jose
• Cobler Brad A
• Kardos Lori L
• Yau Wallace W
• Dow Global Technologies Llc

Inventors

• Karjala Teresa P
• Savargaonkar Nilesh R
• Ortega Jose
• Cobler Brad A
• Kardos Lori L
• Yau Wallace W

Classifications

• C08F110/02

  Ethene · CPC title

• C08L23/04

  Homopolymers or copolymers of ethene · CPC title

• C08F2500/04

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

• C08L2666/04

  Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof · CPC title

• C08F2500/20

  Activation energy or enthalpy · CPC title