Polypropylene with living hinge properties

Patent metadata

Field	Value
Publication number	US-9464664-B2
Application number	US-201113877442-A
Country	US
Kind code	B2
Filing date	Oct 5, 2011
Priority date	Oct 6, 2010
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

The present invention relates to a polypropylene which has—a melt flow rate MFR(230° C., 2.16 kg) of at least 13 g/10 min,—an amount of xylene solubles XS of 6.0 wt % or less, and—a crystalline fraction, wherein at least 10% of the crystalline fraction melts the temperature range of from 160 to 170° C., as determined by the stepwise isothermal segregation technique (SIST).

First claim

The invention claimed is:

1. A polypropylene comprising:
a melt flow rate MFR(230° C., 2.16 kg) of at least 13 g/10 min,
an amount of xylene solubles XS of 6.0 wt % or less,
a crystalline fraction, wherein 10% to 40% of the crystalline fraction melts in the temperature range of from 160 to 170° C., as determined by the stepwise isothermal segregation technique (SIST), and
comonomer units derived from ethylene and/or a C 4-12 alpha-olefin in an amount of 1.5 wt % to 4.0 wt % of the polypropylene.

2. The polypropylene according to claim 1 , wherein the polypropylene has a melting temperature of from 146° C. to 164° C.

3. The polypropylene according to claim 1 , comprising a first propylene polymer fraction F 1 and one or more further propylene polymer fractions, wherein:
the first fraction F 1 contains comonomer units derived from ethylene and/or a C 4 -C 12 alpha-olefin,
the ratio of the amount of comonomer units of the first fraction F 1 to the amount of comonomer units of the polypropylene is less than 1.0, and
the ratio of the melt flow rate MFR(230° C., 2.16 kg) of the first fraction to the melt flow rate MFR(230° C., 2.16 kg) of the polypropylene is 3.0 or less.

4. The polypropylene according to claim 3 , wherein the first fraction has an amount of comonomer units within the range of 0.8 wt % to 3.0 wt %, and/or the first fraction has a melt flow rate MFR(230° C., 2.16 kg) within the range of 13 g/10 min to 35 g/10 min.

5. The polypropylene according to claim 3 , wherein the weight ratio of the first fraction F 1 to the one or more further propylene polymer fractions is within the range of from 30/70 to 70/30.

6. The polypropylene according to claim 1 , comprising a polymeric alpha-nucleating agent comprising monomer units derived from a vinyl compound of the following chemical formula:

wherein R1 and R2 independently from each other represent a substituted or unsubstituted alkyl, cycloalkyl or aryl, or R1 and R2 together form a saturated, unsaturated or aromatic ring system.

7. An article comprising a plastic hinge which comprises the polypropylene according to claim 1 .

Assignees

• Kheirandish Saeid
• Doshev Petar
• Reisecker Michael
• Friel David
• Simon Sybille
• Borealis Ag

Inventors

• Kheirandish Saeid
• Doshev Petar
• Reisecker Michael
• Friel David
• Simon Sybille

Classifications

• C08L2205/02

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

• E05D1/02

  made of one piece · CPC title

• C08F110/06

  Propene · CPC title

• C08F210/06

  Propene · CPC title

• C08L2314/02

  Ziegler natta catalyst · CPC title