Polypropylenes having balanced strain hardening, melt strength, and shear thinning

Patent metadata

Field	Value
Publication number	US-10538645-B2
Application number	US-201615541609-A
Country	US
Kind code	B2
Filing date	Jan 21, 2016
Priority date	Feb 4, 2015
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

A composition comprising the reaction product of a polypropylene comprising at least 50 mol % propylene, and having a molecular weight distribution (Mw/Mn) greater than 6, a branching index (g′ vis ) of at least 0.97, and a melt strength greater than 10 cN determined using an extensional rheometer at 190° C.; and within the range from 0.01 to 3 wt % of at least one organic peroxide, by weight of the polypropylene and organic peroxide. Such hyperbranched polypropylenes are useful in films, foamed articles, and thermoformed articles.

First claim

The invention claimed is:

1. A composition comprising the reaction product of:
a polypropylene comprising at least 50 mol % propylene, and having a molecular weight distribution (Mw/Mn) greater than 6, an Mz/Mw value of greater than or equal to 2.8, a branching index (g′ vis ) of at least 0.97, and a melt strength greater than 10 cN determined using an extensional rheometer at 190° C.; and
within the range from 0.01 to 3 wt % of at least one organic peroxide, by weight of the polypropylene and organic peroxide.

2. The composition of claim 1 wherein the polypropylene has an MWD (Mw/Mn) within the range from 6 to 18.

3. The composition of claim 1 , wherein the polypropylene has a melt strength within the range from 10 cN to 40 cN.

4. The composition of claim 1 , wherein the polypropylene has a Peak Extensional Viscosity (non-annealed) within a range from 10 kPa·s to 60 kPa·s at a strain rate of 0.01/sec (190° C.).

5. The composition of claim 1 , wherein the polypropylene has a heat distortion temperature of greater than or equal to 100° C., determined according to ASTM D648 using a load of 0.45 MPa (66 psi).

6. The composition of claim 1 , wherein the polypropylene comprises at least 90 mol % propylene.

7. The composition of claim 1 , wherein the polypropylene has a melt flow rate (MFR) within the range from 0.1 to 100 g/10 min, determined according to ASTM D1238 Condition L (230° C./2.16 kg).

8. The composition of claim 1 , wherein the polypropylene has an Mz/Mw value of less than 3.6.

9. The composition of claim 1 , the composition having an Mz MALLS /Mw MALLS value of greater than 3.0.

10. The composition of claim 1 , the composition having an MWD MALLS within the range from 10 to 20.

11. The composition of claim 1 , the composition having a branching index (g′ vis ) of less than 0.97.

12. The composition of claim 1 , the composition having a melt strength within the range from 40 cN to 100 cN.

13. The composition of claim 1 , the composition having a Peak Extensional Viscosity (non-annealed) of greater than 50 kPa·s at a strain rate of 0.01/sec (190° C.).

14. The composition of claim 1 , wherein dienes are absent from the composition.

15. The composition of claim 1 , further comprising a foaming agent.

16. A foamed article comprising the reaction product of the foaming agent and composition of claim 15 .

17. The foamed article of claim 16 , the article selected from of cups, plates, and food storage boxes.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Pehlert George J
• Zhao Mosha H

Classifications

• C08J9/04 Primary

  using blowing gases generated by a previously added blowing agent · CPC title

• C08J2201/03

  Extrusion of the foamable blend · CPC title

• C08L2666/28

  Non-macromolecular organic substances · CPC title

• C08F2810/20

  leading to a crosslinking, either explicitly or inherently · CPC title

• C08F8/00

  Chemical modification by after-treatment (graft polymers, block polymers, crosslinking with unsaturated monomers or with polymers C08F251/00 - C08F299/00; of conjugated diene rubbers C08C) · CPC title