Flash spinning process

Patent metadata

Field	Value
Publication number	US-2016362816-A1
Application number	US-201615172753-A
Country	US
Kind code	A1
Filing date	Jun 3, 2016
Priority date	Jun 11, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

A process for the preparation of plexifilamentary film-fibril strands of polymer. The process includes the steps of generating a spin fluid containing (a) 5 to 30 wt. % containing one or more polymer types, (b) a primary spin agent selected from the group consisting of dichloromethane, cis-1,2-dichloroethylene and trans-1,2-dichloroethylene, and (c) a co-spin agent comprising 1H,6H-perfluorohexane or 1H-perfluorohexane or 1H-perfluoroheptane. The spin fluid is flash-spun at a pressure that is greater than the autogenous pressure of the spin fluid into a region of lower pressure to form plexifilamentary film-fibril strands of the polymer. The co-spin agent is present in the spin fluid in an amount sufficient to form an azeotrope-like composition with the primary spin agent in the presence of the one or more polymer types. The polymer may be selected from the group consisting of high density polyethylene, polypropylene, polybutene-1, polymethylpentene, polyvinylidene fluoride, poly (ethylene tetrafluoroethylene), and blends of the foregoing.

First claim

1 . A process for the preparation of plexifilamentary film-fibril strands of polymer which comprises the steps of:
(i) generating a spin fluid comprising (a) 5 to 30 wt. % of total spin fluid being a polymer of one or more polymer types, (b) a primary spin agent selected from the group consisting of dichloromethane, cis-1,2-dichloroethylene and trans-1,2-dichloroethylene, and (c) a co-spin agent selected from the group consisting of 1H,6H-perfluorohexane, 1H-perfluoroheptane, and 1H-perfluorohexane, and (ii) flash-spinning the spin fluid at a pressure that is greater than the autogenous pressure of the spin fluid into a region of lower pressure to form plexifilamentary film-fibril strands of the polymer wherein;
the co-spin agent being present in the spin fluid in an amount sufficient to form an azeotrope or azeotrope-like composition with the primary spin agent in the presence of the polymer.

2 . The process of claim 1 wherein the co-spin agent and the primary spin agent are present in the spin fluid in amounts sufficient to form an azeotrope or azeotrope-like composition in the presence of the polymer that is at the weight % selected in (a).

3 . The process of claim 1 in which the primary spin agent is dichloromethane, the co-spin agent is 1H,6H-perfluorohexane and the ratio of dichloromethane to 1H,6H-perfluorohexane is between 73:27 and 100:0 by weight of total spin agent.

4 . The process of claim 3 wherein the polymer is of a type selected from the group consisting of polyethylene, polypropylene, polybutene-1, poly(4-methyl-1-pentene), polyvinylidenefluoride, and blends of the foregoing.

5 . The process of claim 1 in which the primary spin agent is dichloromethane, the co-spin agent is 1H-perfluorohexane and the ratio of dichloromethane to 1H-perfluorohexane is between 52:48 and 66:34 by weight.

6 . The process of claim 5 wherein the polymer is of a type selected from the group of polypropylene, polybutene-1, poly(4-methyl-1-pentene), polyvinylidenefluoride, poly (ethylene tetrafluoroethylene) and blends of the foregoing.

7 . The process of claim 1 in which the primary spin agent is dichloromethane, the co-spin agent is 1H-perfluoroheptane and the ratio of dichloromethane to 1H-perfluoroheptane is between 70:30 and 89:11 ratio by weight

8 . The process of claim 7 wherein the polymer is of a type selected from the group of polyethylene, polypropylene, polybutene-1, poly(4-methyl-1-pentene), polyvinylidenefluoride, poly (ethylene tetrafluoroethylene) and blends of the foregoing.

9 . The process of claim 1 in which the primary spin agent is trans-1,2-dichloroethylene, the co-spin agent is 1H,6H-perfluorohexane and the ratio of trans-1,2-dichloroethylene to 1H,6H-perfluorohexane is between 72:28 and 100:0 ratio by weight.

10 . The process of claim 9 wherein the polymer is of a type selected from the group of polyethylene, polypropylene, polybutene-1, poly(4-methyl-1-pentene), poly (ethylene tetrafluoroethylene) and blends of the foregoing.

11 . The process of claim 1 in which the primary spin agent is trans-1,2-dichloroethylene, the co-spin agent is 1H-perfluorohexane and the ratio of trans-1,2-dichloroethylene to 1H-perfluorohexane is between 47:53 and 64:36 ratio by weight.

12 . The process of claim 11 wherein the polymer is of a type selected from the group of polypropylene, polybutene-1, poly(4-methyl-1-pentene), poly(ethylene tetrafluoroethylene) and blends of the foregoing.

13 . The process of claim 1 in which the primary spin agent is trans-1,2-dichloroethylene, the co-spin agent is 1H-perfluoroheptane and the ratio of trans-1,2-dichloroethylene to 1H-perfluoroheptane is between 67:33 and 100:0 ratio by weight.

14 . The process of claim 13 wherein the polymer is of a type selected from the group of polyethylene, polypropylene, polybutene-1, poly(4-methyl-1-pentene), poly(ethylene tetrafluoroethylene) and blends of the foregoing.

15 . A process for the preparation of plexifilamentary film-fibril strands of polymer which comprises the steps of:
(i) generating a spin fluid comprising (a) 5 to 30 wt. % of total spin fluid being a polymer of one or more polymer types, (b) a primary spin agent selected from the group consisting of dichloromethane, cis-1,2-dichloroethylene and trans-1,2-dichloroethylene, and (c) a co-spin agent selected from the group consisting of 1H,6H-perfluorohexane, 1H-perfluoroheptane, and 1H-perfluorohexane, and (ii) flash-spinning the spin fluid at a pressure that is greater than the autogenous pressure of the spin fluid into a region of lower pressure to form plexifilamentary film-fibril strands of the polymer wherein;
the co-spin agent being present in the spin fluid in an amount sufficient to form a cloud point.

Assignees

• Du Pont

Inventors

• Schmitz Corneille
• Van Meerveld Jan
• Skoplyak Orest
• Rebouillat Serge

Classifications

• D01D11/00

  Other features of manufacture · CPC title

• D01D5/11 Primary

  Flash-spinning · CPC title

• D01D1/02

  Preparation of spinning solutions · CPC title

• D01F1/10

  Other agents for modifying properties · CPC title

• D01F6/06 Primary

  from polypropylene · CPC title