Method for the Production of Fibres and Other Moulded Articles Comprising Cellulose Carbamate and/or Regenerated Cellulose

Abstract

The invention relates to high-strength fibres and other moulded articles comprising cellulose carbamate or cellulose which is obtained by regeneration of cellulose carbamate, and also production thereof by extrusion of a solution of cellulose carbamate in N-methylmorpholine-N-oxide (NMMNO).

Description

The subject according to the invention is intended to be explained in more detail with reference to the subsequent Figure and examples, without wishing to restrict said subject to these special embodiments.

FIG. 1 shows a schematic representation of the course of the method according to the invention.

The basic course of the method is represented in FIG. 1. The spinning solution 1 is, hereby extruded into a regenerating bath 4 via a spinning pump 2 by means of a nozzle beam 3 which contains a multiplicity of nozzles. Spinning is thereby effected vertically from the top to the bottom via the air gap into the regenerating bath. The fibres are drawn off in the horizontal direction via deflection rollers 5.

Example 1

(comparative example according to the state of the art)

A spinning solution of 9.5% cellulose in NMMO monohydrate with 0.5% by mass propyl gallate as stabiliser was spun in a laboratory spinning unit with a 40 hole nozzle at a temperature of 90° C., a 10% solution of NMMO in water being used as spinning bath (regenerating bath). The filament yarns had a strength of 35 cN/tex and a stretch of 9% with a titre of 8.0 tex.

Example 2

250 g cellulose carbamate (3% nitrogen content, cuoxam DP 300) were mixed in a kneader with 1305 g of a 50% aqueous NMMO solution, this solution was concentrated up to NNMO monohydrate by withdrawing the excess water under a vacuum of 80 mbar and the cellulose carbamate was thereby dissolved. The spinning solution had a cellulose content of 25% by mass. This spinning solution was spun on a laboratory spinning unit with a 40 hole nozzle at a temperature of 100° C., a 10% solution of NMMO in water being used as spinning bath (regenerating bath). The filament yarns had a strength of 65 cN/tex and a stretch of 6% with a titre of 8.1 tex.

Example 3

250 g cellulose carbamate (3% nitrogen content, cuoxam DP 300) were mixed in a kneader with 1305 g of a 50% aqueous NMMO solution, this solution was concentrated up to NNMO monohydrate by withdrawing the excess water under a vacuum of 80 mbar and the cellulose carbamate was thereby dissolved. The spinning solution had a cellulose content of 25% by mass. This spinning solution was spun on a laboratory spinning unit with a 40 hole nozzle at a temperature of 100° C., a 10% solution of NMMO in water being used as spinning bath (regenerating bath). The initially moist fibres were subjected to a subsequent treatment in 0.5% NaOH solution. The filament yarns had a strength of 69 cN/tex and a stretch of 4.5% with a titre of 7.6 tex.

Claims

1. Method for the production of fibres and other moulded articles, in which a lyotropic solution of cellulose carbamate in N-methylmorpholine-N-oxide (NMMNO) is shaped by means of extrusion from at least one nozzle via an air gap into a regenerating bath.

2. Method according to claim 1, characterised in that the ratio of length to diameter of the nozzles is from 1 to 20.

3. Method according to one of the claims 1 or 2, characterised in that the drawing-off ratio is in the range of 5 to 200.

4. Method according to one of the preceding claims, characterised in that the width of the air gap between nozzle and regenerating bath is 5 to 150 mm, in particular 10 to 50 mm.

5. Method according to one of the preceding claims, characterised in that the cellulose carbamate proportion of the lyotropic solution is at least 20% by wt., in particular 22 to 27% by wt., relative to the solution.

6. Method according to one of the preceding claims, characterised in that the lyotropic solution is produced by swelling of the cellulose carbamate in a 40 to 70%, in particular 50% solution of NMMNO in water and subsequent removal of the water up to a ratio of NMMNO to water between 80:20 and 90:10.

7. Method according to one of the preceding claims, characterised in that the regenerating bath comprises a solution of NMMNO in water with an NMMNO proportion of 0.5 to 25% by wt., in particular 5 to 15% by wt., relative to the solution.

8. Method according to one of the preceding claims, characterised in that the extrusion is effected at a temperature between 80 to 110° C., in particular 85 to 95° C.

9. Method according to one of the preceding claims, characterised in that the cellulose carbamate is regenerated into cellulose in a regenerating bath.

10. Method accordiing to the preceding claim, characterised in that the regenerating bath comprises 0.3 to 1% by wt. sodium hydroxide in water and the regeneration is implemented at a temperature of 60 to 95° C.

11. Fibres or other moulded articles comprising cellulose carbamate and/or regenerated cellulose, characterised in that the fibres or other moulded articles have a strength of at least 60 cN/tex.

12. Fibres or other moulded articles according to claim 12, characterised in that the fibres or other moulded articles can be produced according to the method according to one of the claims 1 to 11.