Copolymers of propylene with hexene-1 and blown films obtained from them

Patent metadata

Field	Value
Publication number	US-9611338-B2
Application number	US-73514808-A
Country	US
Kind code	B2
Filing date	Nov 20, 2008
Priority date	Dec 18, 2007
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A copolymer of propylene with hexene-1 containing from 5 to 9% by weight of recurring units derived from hexene-1, having a melting temperature from 125° C. to 140° C. and Melt Flow Rate (ASTM D1238, 230° C./2.16 Kg) from 0.1 to 3 g/10 min., is used to produce blown films having valuable mechanical and optical properties.

First claim

What is claimed is:

1. A propylene copolymer comprising:
5-9% by weight of recurring units derived from hexene-1;
wherein the propylene copolymer has a melting temperature from 125-140° C., a melt flow rate (ASTM D1238, 230° C./2.16 kg) from 0.1 to 3 g/10 min, and a solubility in xylene at room temperature of 18.1% to 25% by weight.

2. A polymerization process for preparing a copolymer of propylene with hexene-1 containing from 5 to 9% by weight of recurring units derived from hexene-1, said copolymer having a melting temperature from 125-140° C., a Melt Flow Rate (ASTM D1238, 230° C./2.16 kg) from 0.1 to 3 g/10 min, and a solubility in xylene at room temperature of 18.1% to 25% by weight, the process comprising polymerizing monomers in the presence of a stereospecific Ziegler-Natta catalyst comprising a solid component containing a titanium compound and an electron-donor compound supported on magnesium chloride, an aluminum alkyl compound and an external electron-donor compound.

3. The polymerization process of claim 2 , wherein the external electron-donor compound is selected from silicon compounds containing at least one Si—OR bond, where R is a hydrocarbon radical.

4. The polymerization process of claim 2 , wherein the external electron-donor compound is thexyltrimethoxysilane.

5. A blown film comprising the propylene copolymer of claim 1 .

6. The blown film of claim 5 , comprising a thickness of less than 250 μm.

7. An article comprising the blown film of claim 5 , selected from an industrial package, a food package, a bag, a sack, a lamination film, a barrier film, an agriculture film and a hygienic product.

8. A process comprising blow molding a film comprising at least one film layer in a blown film process, the film layer comprising a copolymer of propylene with hexene-1 containing from 5 to 9% by weight of recurring units derived from hexene-1, said copolymer having a melting temperature from 125-140° C., a Melt Flow Rate (ASTM D1238, 230° C./2.16 kg) from 0.1 to 3 g/10 min, and a solubility in xylene at room temperature of 18.1% to 25% by weight.

9. The process of claim 8 , carried out under the following conditions:
a screw length from 20 to 40 times the screw diameter;
a barrel and die temperature from 160 to 270° C.;
an annular die gap of at most 3 mm;
a blow-up ratio from 2.2 to 4; and
a cooling medium temperature from 5 to 20° C.

10. The copolymer of claim 1 , further comprising a clarifying agent.

11. The copolymer of claim 10 , wherein the clarifying agent is selected from the group consisting of 3,4-dimethylbenzylidene sorbitol and hexafluoropropylene (HFP)-vinylidene fluoride (VF)-tetrafluoroethylene (TFE).

12. The copolymer of claim 1 , comprising a molecular weight distribution from 4 to 7.

13. The copolymer of claim 1 , comprising an isotacticity index equal to or higher than 97%.

Assignees

• Pellegatti Giampaolo
• Grazzi Michele
• Kokel Nicolas
• Angelini Antonella
• Basell Poliolefine Italia Srl

Inventors

• Pellegatti Giampaolo
• Grazzi Michele
• Kokel Nicolas
• Angelini Antonella

Classifications

• B29K2023/14

  Copolymers of polypropylene (B29K2023/16 takes precedence) · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08F210/06

  Propene · CPC title

• B29C2793/0063

  Cutting longitudinally · CPC title

• B29C48/0018

  combined with shaping by orienting, stretching or shrinking, e.g. film blowing (B29C48/0017 takes precedence) · CPC title