Propylene polymer for high-tenacity fibers and nonwovens

Patent metadata

Field	Value
Publication number	US-10023663-B2
Application number	US-201314411250-A
Country	US
Kind code	B2
Filing date	Jun 27, 2013
Priority date	Jun 27, 2012
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

Propylene polymers having a melt flow index in the range from 3.0 dg/min to 8.0 dg/min can be particularly suited for high-tenacity fibers and yarns and nonwovens. The propylene polymers can be produced by a process that includes polymerizing propylene or propylene and at least one comonomer in presence of a Ziegler-Natta polymerization catalyst, an aluminium alkyl, and hydrogen.

First claim

The invention claimed is:

1. A propylene polymer with up to and including 1.0 wt %, relative to the total weight of the propylene polymer, of at least one comonomer selected from the group of alpha-olefins consisting of ethylene, butane-1, pentene-1,4-methyl-pentene-1 and octene-1, said propylene polymer comprising:
a melt flow index in the range from 3.0 to 8.0 dg/min, determined according to ISO 1133, condition L, 230° C., 2.16 kg,
a xylene solubles content in the range from 1.0 wt % to 3.5 wt %, relative to the total weight of the propylene polymer,
a polydispersity index of at least 3.0 and of at most 5.0,
a content of mmmm pentads in the range from 97.0% to 99.0%, determined on the insoluble heptane fraction of the xylene insolubles fraction, and
a recovery compliance in the range from 2.5·10 −4 Pa −1 to 5.5·10 −4 Pa −1 .

2. The propylene polymer according to claim 1 with up to and including 0.05 wt %, relative to the total weight of the propylene polymer, of at least one comonomer selected from the group of alpha-olefins consisting of ethylene, butene-1, pentene-1, 4 -methyl-pentene-1 and octene-1.

3. The propylene polymer according to claim 2 , wherein the melt flow index is in the range from 4.0 dg/min to 8.0 dg/min, determined according to ISO 1133, condition L, at 230° C. and 2.16 kg.

4. The propylene polymer according to claim 2 , wherein the xylene solubles content is in the range from 1.5 wt % to 3.5 wt %, relative to the total weight of the propylene polymer.

5. The propylene polymer according to claim 2 , wherein the recovery compliance is in the range from 4.0·10 −4 Pa −1 to 5.5·10 −4 Pa −1 .

6. The propylene polymer according to claim 1 , with from more than 0.05 wt % to 1.0 wt %, relative to the total weight of the propylene polymer, of at least one comonomer selected from the group of alpha-olefins consisting of ethylene, butene-1, pentene-1, 4 -methyl-pentene-1 and octane-1.

7. The propylene polymer according to claim 6 , wherein the melt flow index is in the range from 3.0 dg/min to 6.0 dg/min, determined according to ISO 1133, condition L, at 230° C. and 2.16 kg.

8. The propylene polymer according to claim 6 , wherein the xylene solubles content is in the range from 1.5 wt % to 3.0 wt %, relative to the total weight of the propylene polymer.

9. The propylene polymer according to claim 6 , wherein the recovery compliance is in the range from 3.0·10 −4 Pa −1 to 4.5·10 −4 Pa −1 .

10. Fibers or yarns comprising the propylene copolymer of claim 1 .

11. Nonwovens comprising the fibers of claim 10 .

12. A process for the production of the propylene polymer comprising the step of
(a) polymerizing propylene or polymerizing propylene and at least one comonomer in presence of a Ziegler-Natta polymerization catalyst, an aluminium alkyl, and hydrogen, said Ziegler-Natta polymerization catalyst comprising a titanium compound, which has at least one titanium-halogen bond, and an internal donor, both supported on magnesium halide in active form,
wherein the process is controlled so as to produce propylene polymer with:
1.0 wt %, relative to the total weight of the propylene polymer, of at least one comonomer; consisting of ethylene, butane-1, pentene-1,4 -methyl-pentene-1 and octane-1;
a melt flow index in the range from 3.0 to 8.0 dg/min, determined according to ISO 1133, condition L, 230° C., 2.16 kg;
a xylene solubles content in the range from 1.0 wt % to 3.5 wt %, relative to the total weight of the propylene polymer;
a polydispersity index of at least 3.0 and of at most 5.0;
a content of mmmm pentads in the range from 97.0% to 99.0%, determined on the insoluble heptane fraction of the xylene insolubles fraction; and
a recovery compliance in the range from 2.5·10 −4 Pa −1 to 5.5·10 −4 Pa −1 .

13. The process according to claim 12 , wherein the Ziegler-Natta polymerization catalyst has an internal electron donor that comprises at least 80 wt % of a diether.

14. The process according to any of claim 12 , further comprising the steps of
(b) melting the propylene copolymer obtained in step (a) in an extruder,
(c) extruding the molten propylene copolymer of step (b) from a number of fine capillaries of a spinneret, thus obtaining molten fibers, and
(d) subsequently solidifying the fibers of step (c).

15. The process according to claim 14 , further comprising the steps of
(e) re-heating the solidified fibers of step (d) to a temperature of 130° C. or less,
(f) drawing said re-heated fibers of step (e) with a draw ratio of at least 2.5, and
(g) annealing said drawn fibers obtained in step (f).

16. The propylene polymer according to claim 1 , wherein the melt flow index is in the range from 4.5 dg/min to 7.5 dg/min, determined according to ISO 1133, condition L, at 230° C. and 2.16 kg.

17. The propylene polymer according to claim 1 , wherein the melt flow index is in the range from 5.0 dg/min to 7.0 dg/min, determined according to ISO 1133, condition L, at 230° C. and 2.16 kg.

Assignees

• Total Res & Technology Feluy

Inventors

• Geeurickx Peter
• Standaert Alain
• Zuliani Jean-Luc

Classifications

• D01D10/02

  Heat treatment (heating for finishing D02J13/00) · CPC title

• Y10T442/60

  Nonwoven fabric [i.e., nonwoven strand or fiber material] · CPC title

• D01D5/12 Primary

  Stretch-spinning methods ({D01D5/098 takes precedence} finishing by stretching D02J1/22) · CPC title

• B29K2023/14

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

• D01F6/30

  comprising olefins as the major constituent · CPC title