POLYMER FIBRE HAVING IMPROVED LONG-TERM DISPERSIBILITY

Abstract

The invention relates to a polymer fibre having improved long-term dispersibility, a method for production thereof, and use thereof.

The polymer fibre according to the invention comprises at least one synthetic polymer and a preparation present on the surface of the fibres, said preparation comprising at least one cellulose ether selected from the group carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methylethyl cellulose (MEC), hydroxyethylmethyl cellulose (HEMC), hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, and mixtures thereof.

The polymer fibre according to the invention has improved dispersibility and is thus suitable for the preparation of aqueous suspensions which are used, for example, in the formation of textile fabrics, for example nonwovens.

Claims

1. A method for stabilization of aqueous dispersions comprising: providing an aqueous dispersion which comprises water; adding synthetic polymer fibers to the aqueous dispersion wherein the synthetic polymer fibers have, on a surface thereof, a preparation including at least one cellulose ether selected from the group carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methylethyl cellulose (MEC), hydroxyethylmethyl cellulose (HEMC), hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, and mixtures thereof, and the at least one cellulose ether has a gelling temperature in the range of 35 C. to 90 C. and the preparation covers at least 99.9% of the total surface of the fiber; wherein the preparation has a thickness of 5-10 nm, and wherein the fiber is a staple fiber having a titre between 0.3 and 30 dtex.

2. The method according to claim 1, wherein the synthetic polymer is a thermoplastic polymer.

3. The method according to claim 1, wherein the synthetic polymer is selected from the group of polymers comprising acrylonitrile ethylene propylene (diene) styrene copolymer, acrylonitrile methacrylate copolymer, acrylonitrile methyl methacrylate copolymer, acrylonitrile chlorinated polyethylene styrene copolymer, acrylonitrile butadiene styrene copolymer, acrylonitrile ethylene propylene styrene copolymer, aromatic polyester, acrylonitrile styrene acryloester copolymer, butadiene styrene copolymer, cellulose acetate, cellulose acetobutyrate, cellulose acetopropionate, hydrated cellulose, carboxymethyl cellulose, cellulose nitrate, cellulose propionate, cellulose triacetate, polyvinylchloride, ethylene acrylic acid copolymer, ethylene butylacrylate copolymer, ethylene chlorotrifluoroethylene copolymer, ethylene ethylacrylate copolymer, ethylene methacrylate copolymer, ethylene methacrylic acid copolymer, ethylene tetrafluoroethylene copolymer, ethylene vinylalcohol copolymer, ethylene butene copolymer, ethylcellulose, polystyrene, polyfluoroethylene propylene, methylmethacrylate acrylonitrile butadiene styrene copolymer, methylmethacrylate butadiene styrene copolymer, methylcellulose, polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 6-3-T, polyamide 6-terephthalic acid copolymer, polyamide 66, polyamide 69, polyamide 610, polyamide 612, polyamide 61, polyamide MXD 6, polyamide PDA-T, polyamide, polyarylether, polyaryletherketone, polyamide imide, polyarylamide, polyamino-bis-maleimide, polyarylate, polybutene-1, polybutylacrylate, polybenzimidazole, poly-bis-maleimide, polyoxadiazobenzimidazole, polybutylene terephthalate, polycarbonate, polychiorotrifluoroethylene, polyethylene, polyestercarbonate, polyaryletherketone, polyetheretherketone, polyetherimide, polyetherketone, polyethylene oxide, polyarylethersulfone, polyethylene terephthalate, polyimide, polyisobutylene, polyisocyanurate, polyimide sulfone, polymethacrylimide, polymethacrylate, poly-4-methylpentene-1, polyacetal, polypropylene, polyphenylene oxide, polypropylene oxide, polyphenylene sulfide, polyphenylene sulfone, polystyrene, polysulfone, polytetrafluoroethylene, polyurethane, polyvinylacetate, polyvinylalcohol, polyvinylbutyral, polyvinylchloride, polyvinylidene chloride, polyvinylidene fluoride, polyvinylfluoride, polyvinylmethylether, polyvinylpyrrolidone, styrene butadiene copolymer, styrene isoprene copolymer, styrene maleic acid anhydride copolymer, styrene maleic acid anhydride butadiene copolymer, styrene methylmethacrylate copolymer, styrene methylstyrene copolymer, styrene acrylonitrile copolymer, vinylchloride ethylene copolymer, vinylchloride methacrylate copolymer, vinylchloride maleic acid anhydride copolymer, vinylchloride maleimide copolymer, vinylchloride methylmethacrylate copolymer, vinylchloride octylacrylate copolymer, vinylchloride vinylacetate copolymer, vinylchloride vinylidene chloride copolymer and vinylchloride vinylidene chloride acrylonitrile copolymer.

4. The method according to claim 1, wherein the synthetic polymer is a polyester.

5. The method according to claim 1, wherein the synthetic polymer is a synthetic biopolymer.

6. The method according to claim 5, wherein the synthetic biopolymer is polylactic acid and has a number-average molecular weight (Mn) of at least 500 g/mol.

7. The method according to claim 5, wherein the synthetic biopolymer is polylactic acid and a number-average molecular weight (Mn) of at most 1,000,000 g/mol.

8. The method according to claim 5, wherein the synthetic biopolymer is polylactic acid and has a weight-average molecular weight (Mw) in the range of 750 g/mol to 5,000,000 g/mol.

9. The method according to claim 5, wherein the synthetic biopolymer is polylactic acid and has a polydispersity in the range of from 1.5 to 5.

10. The method according to claim 5, wherein the synthetic biopolymer is polylactic acid and is a poly-D-, poly-L- or poly-D,L-lactic acid.

11. The method according to claim 1, wherein the fiber is a bicomponent fiber, the fiber consisting of a core component A and a shell component B, and the melting point of core component A is at least 5 C. higher than the melting point of shell component B.

12. The method according to claim 1, wherein between 0.1 and 20 wt. % of the preparation is applied to the surface of the fiber.

13. The method according to claim 1, wherein the preparation comprises at least two cellulose ethers selected from the group carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methylethyl cellulose (MEC), hydroxyethylmethyl cellulose (HEMC), hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose.

14. The method according to claim 1, wherein the at least one cellulose ether has a gelling temperature in the range of 40 C. to 70 C.

15. The method according to claim 1, wherein the at least one cellulose ether has a degree of substitution (number of substituted hydroxy groups per glucose molecule) in the range of from 1.3 to 2.6.

16. The method according to claim 1, wherein the at least one cellulose ether is methyl celluloses with a methoxy group fraction of from 26% to 33%.

17. The method according to claim 1, wherein the at least one cellulose ether is hydroxypropyl celluloses with a hydroxypropyl group fraction of at most 5%.

18. The method according to claim 1, wherein the at least one cellulose ether has a methoxy group fraction of from 26% to 33%, and a hydroxypropyl group fraction of at most 5%.

19. The method according to claim 1, wherein the at least one cellulose ether has a methoxy group fraction of from 26% to 33%, and a hydroxypropyl group fraction of from 7% to 12.

20. The method according to claim 1, wherein the aqueous dispersion further comprises mineral particles.

21. A method for stabiization of an aqueous system comprising: providing an aqueous system which comprises saline-based electrolytes wherein the aqueous system has a pH of <7; adding to the aqueous system synthetic polymer fibers wherein the synthetic polymer fibers have, on a surface thereof, a preparation including at least one cellulose ether selected from the group carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methylethyl cellulose (MEC), hydroxyethylmethyl cellulose (HEMC), hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, and mixtures thereof; and subjecting the aqueous system to high pressure, severe shear forces and elevated temperature.

22. A method of preparing a fiber having a titre between 0.3 and 30 dtex comprising: extruding a synthetic polymer to form a molten synthetic polymer; spinning the molten synthetic polymer to form a solidified thread; stretching the solidified thread to form a fiber; applying to the fiber a preparation including at least one cellulose ether selected from the group carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), methylethyl cellulose (MEC), hydroxyethylmethyl cellulose (HEMC) to the, hydroxypropylmethyl cellulose (HPMC), ethylhydroxyethyl cellulose, carboxymethylhydroxyethyl cellulose, and mixtures thereof; and drying the fiber in a hot air oven at a temperature of at most 120 C.

Description

EXAMPLES

[0097] Methyl cellulose solution was applied to melt-spun PLA fibres during processing on the conveyor line and was then dried. The produced PLA fibres thus have a preparation on the surface comprising at least one methyl cellulose (MC).

[0098] The produced PLA fibres comprise the preparation according to the invention on at least 99% of the total surface of the fibres.

[0099] The PLA fibres according to the invention were cut to a length of 6 mm, and 1 gram of the cut PLA fibres was dispersed and examined at room temperature (25 C.) as described beforehand.

[0100] For comparison, 1 gram PLA fibres without the additive according to the invention, but otherwise identical, was dispersed and examined at room temperature (25 C.) as described above.

[0101] The fibres according to the invention, in contrast to the comparison fibres (without the finish according to the invention), demonstrate a much improved long-term dispersion, and a much improved permanence of the dispersibility following a few weeks storage.