Technique for forming porous fibers

Patent metadata

Field	Value
Publication number	US-11724002-B2
Application number	US-201816470858-A
Country	US
Kind code	B2
Filing date	Jan 19, 2018
Priority date	Feb 28, 2017
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

A method for forming a fiber is provided. The method comprises extruding a matrix polymer and a nanoinclusion additive to form a thermoplastic composition in which the nanoinclusion additive is dispersed within a continuous phase of the matrix polymer. The extruded thermoplastic composition is thereafter passed through a spinneret to form a fiber having a porous network containing a plurality of nanopores, wherein the average percent volume occupied by the nanopores within a given unit volume of the fiber is from about 3% to about 15% per cm3.

First claim

What is claimed is:

1. A method for forming a fiber, the method comprising:
extruding a matrix polymer and a nanoinclusion additive to form a thermoplastic composition in which the nanoinclusion additive is dispersed within a continuous phase of the matrix polymer, wherein the nanoinclusion additive contains a copolyetherester elastomer; and
thereafter, passing the extruded thermoplastic composition through a spinneret to form a fiber having a porous network containing a plurality of nanopores, wherein the average percent volume occupied by the nanopores within a given unit volume of the fiber is from about 3% to about 15% per cm 3 .

2. The method of claim 1 , wherein the spinneret has a length-to-diameter ratio of about 6:1 or less.

3. The method of claim 1 , wherein the ratio of the melt flow rate of the matrix polymer to the melt flow rate of the nanoinclusion additive is about 2:1 or more.

4. The method of claim 1 , wherein the nanoinclusion additive has a melt flow rate of from about 0.1 to about 50 grams per 10 minutes, determined at a load of 2160 grams and at a temperature at least about 40° C. above the melting temperature of the nanoinclusion additive in accordance with ASTM D1238-13.

5. The method of claim 1 , wherein the matrix polymer has a melt flow rate of from about 0.5 to about 80 grams per 10 minutes, determined at a load of 2160 grams and at a temperature at least about 40° C. above the melting temperature of the matrix polymer in accordance with ASTM D1238-13.

6. The method of claim 1 , wherein extrusion occurs at a temperature of from about 180° C. to about 340° C.

7. The method of claim 1 , further comprising quenching the fiber after it is passed through the spinneret.

8. The method of claim 1 , wherein the fiber is a substantially continuous filament.

9. The method of claim 1 , wherein the fiber has a diameter of from about 1 to about 100 micrometers.

10. The method of claim 1 , wherein the nanoinclusion additive constitutes from about 0.01 wt. % to about 15 wt. % of the thermoplastic composition.

11. The method of claim 1 , wherein the nanoinclusion additive contains a siloxane polymer.

12. The method of claim 1 , wherein the nanoinclusion additive contains a polyepoxide.

13. The method of claim 1 , wherein the nanopores have an average cross-sectional dimension of about 800 nanometers or less.

14. The method of claim 1 , wherein the nanopores have an average axial dimension of from about 100 to about 5000 nanometers.

15. The method of claim 1 , wherein the matrix polymer includes a polyester.

16. The method of claim 15 , wherein the polyester is polyethylene terephthalate.

17. The method of claim 1 , wherein the matrix polymer includes a polyolefin.

18. The method of claim 17 , wherein the polyolefin is a propylene homopolymer.

19. The method of claim 1 , wherein the continuous phase constitutes from about 60 wt. % to about 99 wt. % of the thermoplastic composition.

20. The method of claim 1 , wherein the matrix polymer includes a polyester and wherein the continuous phase constitutes from about 60 wt. % to about 99 wt. % of the thermoplastic composition.

Assignees

• Kimberly Clark Co

Inventors

• Mceneany Ryan J
• Topolkaraev Vasily A
• Xu Yuewen

Classifications

• A61L15/26 Primary

  Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof {(A61L15/225 takes precedence)} · CPC title

• C08L67/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence) · CPC title

• D01D5/247

  Discontinuous hollow structure or microporous structure · CPC title

• D01F1/08

  for forming hollow filaments · CPC title

• D01F6/04

  from polyolefins · CPC title