WO2018137757A1

WO2018137757A1 - Spinning solution containing cellulose carbamate and cellulose xanthate, method for the production of shaped bodies, and correspondingly produced shaped bodies

Info

Publication number: WO2018137757A1
Application number: PCT/EP2017/051419
Authority: WO
Inventors: André Lehmann; Robert Protz; Gerd Weidel
Original assignee: Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V.
Priority date: 2017-01-24
Filing date: 2017-01-24
Publication date: 2018-08-02
Also published as: EP3574137A1

Abstract

The present invention relates to a spinning solution which contains or consists of cellulose carbamate and cellulose xanthate and a suitable solvent. The cellulose carbamate and the cellulose xanthate are present in the solvent in dissolved form. The present invention also relates to the production of a shaped body, in particular of a filament, by means of a shaping method, in particular a spinning method, from the aforementioned spinning solution. The invention also relates to a correspondingly produced shaped body, in particular a filament, which contains or consists of cellulose carbamate and cellulose xanthate.

Description

The present invention relates to a spinning solution which contains or consists of cellulose carbamate and cellulose xanthogenate and also a suitable solvent. The cellulose carbamate and the cellulose xanthate are dissolved in the solvent. In addition, the present invention relates to the production of a shaped body, in particular a filament by means of a shaping process, in particular a spinning process of the aforementioned spinning solution. The invention also relates to a correspondingly produced shaped body, in particular a filament, which contains or consists of cellulose carbamate and cellulose xanthogenate.

Synthetic fibers from regenerated cellulose are currently produced at a production volume of about 5 million t / a, with more than 90% being produced by the viscose process. Here is a Derivatization of cellulose with carbon disulfide (CS ₂ ) to cellulose xenonogenate instead. This method in which an average of 30% highly toxic carbon disulfide based on the cellulose as Derivatisierungsagenz is used (the amount varies depending on the type of fiber (modal, tire cord, textile) or molding (foil, sponge) allows due to the chemical and physical conditions of the process Variation of process-relevant and therefore final structural parameters such as degree of polymerization, orientation of the crystalline and amorphous regions and cross-sectional morphology For 1000 kg of cellulosic synthetic fiber (molded body) after the viscose process, an average of 300 kg of CS _{2 are} required.

In recent years, the improvement of existing viscose productions by optimizing the use of chemicals, in particular reduction of carbon disulfide consumption (CS ₂ ) is the focus of current research.

The complete avoidance of carbon disulphide is used in the Lenzing AG industrially realized Lyoce Ii method and the cellulosic synthetic fiber (Tencel ^® ) obtained therefrom commercially available in a current amount of about 225 kt / a. In this method, no derivatization is carried out on the cellulose, but aqueous N-methyl-morpholine-N-oxide used as a solvent. Therefore, this process is one of the so-called direct dissolution process. This results in high dope viscosities which require significantly more expensive process equipment to promote and filter such dope. Furthermore, in contrast to the viscose process, this process also requires the air gap spinning process for shaping the spinning solution into shaped articles such as staple fibers. Due to the non-existent derivatization of cellulose and the different spinning process, regenerated cellulosic fibers are produced which differ structurally and thus from the textile-physical properties of viscose fibers. Although the Lyoce II process makes it possible to omit CS ₂ altogether, other thread properties than those of viscose fibers result (see bold mark before), which is why lyocell fibers can only be used to a limited extent in fields of application in which viscose fibers are used. The Lyoce II method finds no

Derivatisierungder cellulose instead. The molded bodies produced, in particular Spun fibers produced therefrom have a different spectrum of the textile-physical characteristics and, in particular, exhibit a high tendency to fibrillate due to the high orientation of the amorphous regions of the semicrystalline cellulose polymer.

Another method known in the art is the carbamate process. Here, the cellulose used is derivatized with urea to cellulose carbamate. However, a disadvantage of molded articles produced by this process, in particular staple fibers, is their relatively high brittleness compared to viscose fibers.

Synthetic fibers produced by the viscose process thus differ from synthetic fibers produced after the carbamate process in terms of their structure and their superior mechanical properties.

On the part of research, the transformation of dissolved pulp from ionic liquids (Sixta, WO / 2014/162062), mixtures of urea and caustic soda (Zhang US12088686A1) and caustic soda (Struszczyk DE60123377T2) have themselves been advanced as a direct dissolution process, sometimes to pilot scale. These methods only allow a conditional influence on the structure formation during the regeneration in the precipitation bath, since this is based mainly on the exchange of solvent to non-solvent (precipitation bath).

Based on the above-discussed disadvantages of the prior art, it is the object of the present invention to provide a spinning solution, a process for producing a shaped body, in particular staple fibers and a shaped body, in particular staple fibers, wherein the physical-chemical properties of the produced Form body not at all or only slightly different from the physico-chemical properties of moldings, which were produced by the viscose process. In particular, the spinning solution according to the invention or the production process should make it possible to work for the viscose process while minimizing carbon disulfide in the comparison. In addition, it is an object of the present invention to provide new structure-property relationships in the moldings produced enable.

This object is achieved in terms of a spinning solution with the features of claim 1, with regard to a method for producing a shaped body, in particular a filament having the features of claim 10 and with respect to a shaped body, in particular a filament with the features of claim 19. The respective dependent claims represent advantageous developments.

The spinning solution according to the invention according to claim 1 contains cellulose carbamate and cellulose xanthate, which are dissolved in a suitable solvent. The term "solvent" in this case comprises a single suitable solvent and mixtures of a number of suitable solvents The spinning solution may alternatively also be formed from the abovementioned substances, ie cellulose carbamate, cellulose xanthate and solvent, so that, if appropriate, no further additives are present.

It has been found that by replacing parts of the cellulose xanthate (cellulose derivative from reaction of cellulose with CS ₂ in the viscose process) by cellulose carbamate in the spinning solution, the amount of CS ₂ required per amount of formed cellulose molded body can be reduced, thus saving CS ₂ compared to the viscose process can be. The spinning solution used thus has a reduced sulfur content. In spite of all this, it was possible, surprisingly, to retain the mechanical properties of the shaped bodies produced from the spinning solution, in particular of the spun fibers produced. These are equal to those of the staple fibers from the viscose process.

As a result, a more environmentally friendly and less toxic variant or modification of the viscose process can be provided.

The spinning solution according to the invention is in particular free of externally added carbon disulfide.

The particular advantage of the spinning solution according to the invention is that it has a shaping process, for example, a spinning process can be subjected, while maintaining the xanthate polyelectrolyte structure of the cellulosic material to be formed during the spinning process. This makes it possible to influence the diffusion processes and the coagulation rate by salts contained in the spinning bath during the regeneration of the dissolved cellulosic polymers. As a result, structural parameters such as crystallite size and orientation, degree of crystallinity and overall orientation of the cellulosic polymer chains can be varied over a larger range than is possible, for example, in the lyocell or carbamate process alone (compare characteristic values for the elongation Ex. 1 and Ex. 3) ,

The spinning solution according to the invention can be prepared by dissolving cellulose carbamate and cellulose xanthogenate in the solvent by stirring or kneading. The dissolution process is preferably carried out at temperatures below 10 ° C, more preferably below 0 ° C.

A preferred embodiment provides that the cellulose carbamate and / or the cellulose xanthate a DP _CU oxam (determined according to SCAN-CM 15:99) of 150 to 750, preferably from 250 to 550.

It is also advantageous if the cellulose has a degree of substitution of carbamate (DP rbamat _Ca) of 0.1 to 1, preferably from 0.2 to 0.6.

The cellulose xanthate can be prepared prior to introduction into the spinning solution by reaction of cellulose with CS ₂ analogously to the viscose process.

The cellulose xanthate preferably has a fresh y value (determined by Fock, Svensk Papperstidn, 60 (1957), 911-912) of 100 to 30, preferably 60 to 40.

In a further preferred embodiment, the cellulosic solids content, ie the total weight of cellulose carbamate and cellulose xanthogenate of the spinning solution of 4 to 15 wt .-%, preferably from 6 to 10 wt .-%. The spinning solution preferably has a content of cellulose carbamate of 1 to 15 wt .-%, preferably from 2 to 8 wt .-% and / or cellulose xanthate from 1 to 15 wt .-%, preferably from 2 to 8 wt .-% to.

In particular, it is advantageous if the weight ratio of cellulose carbamate to cellulose xanthogenate is from 5:95 to 95: 5, preferably from 60:40 to 85:15, particularly preferably from 65:35 to 70:30. Preferably, the solvent is selected from the group consisting of

Alkali solutions, in particular sodium hydroxide solution or potassium hydroxide solution, wherein preferably the concentration of alkali in the alkali metal hydroxide solution is 4 to 12% by weight, preferably 5 to 10% by weight, particularly preferably 6 to 9% by weight. In order to facilitate the processing of the spinning solution according to the invention, spinning aids, in particular inorganic spinning aids, such as, for example, can be used. Zinc oxide; organic spin agents, such as e.g. quaternary ammonium compounds; Alkyl ethers, e.g. polyoxyethylene glycol; sulfonated oils and / or mixtures thereof.

The present invention also relates to processes for producing a shaped body, in particular a filament, a bead, a sponge, a film of a spinning solution according to the invention, wherein the spinning solution by means of a shaping step in a molded body, transferred and during and / or after the forming Step, the solvent is removed from the molding.

In particular, the process according to the present invention relates to the production of filaments, in which case a spinning solution according to the invention is spun into filaments by means of a spinneret and the filaments produced are introduced into a coagulation bath.

The coagulation bath preferably contains water, and dissolved therein at least one component selected from the group consisting of inorganic acids, such as sulfuric acid; Salts, such as sodium sulfate; as well as organic liquids, for example glycerol or is formed therefrom. It is particularly advantageous if the spinning solution is freshly prepared in the solvent before the shaping step, in particular spinning by dissolving the cellulose carbamate and the cellulose xanthate and then ripened, the tire preferably over a period of 1 to 72 hours, more preferably from 5 to 36 hours, more preferably 12 to 24 hours and / or at temperatures of the spinning solution of -10 to +50 ° C, preferably 0 to 30 ° C, particularly preferably 15 to 25 ° C is performed.

Preferably, the coagulation bath to a temperature of 10 to 90 ° C, preferably 20 to 70 ° C, particularly preferably 30 to 50 ° C tempered.

After removal from the coagulation bath, the filaments can be fed to a stretching bath and stretched there, preferably with a stretching factor of 1.1 to 4, in particular 1.5 to 2.5.

The aforementioned stretching bath in this case is preferably an aqueous solution of an inorganic acid, which in particular includes sulfuric acid and / or at temperatures of 50 to 99 ° C, preferably from 60 to 90 ° C, more preferably 75 to 85 ° C tempered.

In the case of the production of filaments, these are preferably drawn off from the spinneret with a nozzle delay of 0.3 to 2.0, preferably 0.5 to 1.5, in particular 0.6 to 0.8.

The resulting shaped articles, in particular filaments, are preferably finally washed, in particular with water or, in particular, subsequently dried.

The invention additionally relates to a shaped body, in particular filament, pearl, sponge, foil, containing or consisting of cellulose carbamate and cellulose xanthogenate.

The shaped body described above is preferably produced or producible by a process according to the invention. The present invention will be further illustrated by the following examples, without limiting the invention thereto. The measured values determined in the examples became as follows

Rules determined:

Tear strength: determined according to DIN EN ISO 527-1: 2012 Elongation: determined according to DIN EN ISO 5079: 1996

Modulus of elasticity: determined in accordance with EN ISO 527-1: 2012 Example 1 (carbamate process)

9% Cellulosecarbamat (CC, DP _Cu oxam: 258, N content 2.2%) was dissolved in a 7 wt% aqueous sodium hydroxide solution in the cold at -4 ° C with stirring within 90 min. The Nachreife took place overnight for 20h at 22 ° C. The spinning solution thus produced was at a temperature of +5 ° C by means of a spinning pump to the spinneret (300 hole, 70μιη), which in a 40 ° C tempered, aqueous spinning bath of 80 g / l sulfuric acid and 240 g / l sodium sulfate, promoted , The coagulated filaments were drawn off by means of a nozzle delay of 0.7 and further in a stretching bath (stretching factor 1.15, 80 ° C, 20 g / l H ₂ S0 ₄ ) and then the laundry (60 ° C, distilled water) supplied before they were dried isometrically at 80 ° C using dry palettes and finally wound up as filament yarn.

The filaments thus produced had a tensile strength of 17 cN / tex, an elongation of 6% and an elastic modulus of 1020 cN / tex.

No external CS _{2 was used} for this transformation. Exemplary embodiment 2 (viscose process)

8% Na cellulose xanthogenate (CX, DP _Cu oxam: 330, fresh y value: 51.8) was allowed to set in a 7% by weight aqueous sodium hydroxide solution in the cold at 0 ° C Stirred within 90 min. The Nachreife took place overnight for 20h at 22 ° C.

The spinning solution thus produced was fed to the spinning nozzle at a spinning-y value of 38 at a temperature of +10 ° C. by means of a spinning pump (300 hole,

70μιη), which in a 40 ° C tempered, aqueous spinning bath of 80 g / l sulfuric acid and 240 g / l sodium sulfate protruded promoted. The coagulated filaments were drawn off by means of a nozzle delay of 0.7 and further in a stretching bath (stretching factor 1.15, 80 ° C, 20 g / l H ₂ S0 ₄ ) and then the laundry (60 ° C, distilled water ) were fed before they were dried isometrically at 80 ° C with the help of dry pallets and finally wound up as filament yarn.

The filaments thus produced had a tensile strength of 17 cN / tex, an elongation of 18% and an E modulus of 780 cN / tex.

Here, 32 parts of CS ₂ based on the parts of the cellulose regenerated filaments produced were used for this shaping. Example 3

Na cellulose _xanthate (CX, DP _CuO x: 340, fresh y value: 52.4) was dissolved in caustic at 5 ° C to realize cellulose content of 8.8% by weight and an alkali content of 7.0% by weight , Further, cellulose carbamate (CC, DPcuox: 258, N content 2.2%) was dissolved in a 7 wt% sodium hydroxide aqueous solution in the cold at -4 ° C with stirring within 90 minutes to give a CC concentration of 9.5 % to realize.

To the solution of cellulose carbamate in 7% by weight of alkali, the solution of CX was added with stirring to adjust a ratio of CC: CX of 67:33, the final resulting cellulose concentration being 8.5% by weight and that of the alkali being 7% by weight.

The thus produced low-viscosity spinning solution was after maturity (20h at 22 ° C) at a temperature of +5 ° C by means of a spinning pump to the spinneret

(300 hole, 70μιη), which in a 40 ° C tempered aqueous spin bath 80 g / l sulfuric acid and 240 g / l sodium sulfate protruded, promoted. The coagulated filaments were drawn off by means of a nozzle delay of 0.7 and further in a stretching bath (stretching factor 1.15, 80 ° C, 20 g / l H ₂ S0 ₄ ) and then the laundry (60 ° C, distilled water) supplied before they were dried isometrically at 80 ° C using dry palettes and finally wound up as filament yarn.

The filaments thus produced had a tenacity of 17 cN / tex, an elongation of 12% and a modulus of 970 cN / tex.

Furthermore, the nozzle distortions were varied to 0.6 and 0.9 at a constant stretching factor, resulting in the following textile-physical properties of the individual filaments:

DV Tear strength modulus [cN / tex] Elongation at break [%]

[CN / tex]

0.6 17 ± 0.7 938 ± 53 15 ± 1.6

0.9 18 ± 0.8 990 ± 45 11 ± 0.7

In order to produce the CX, 10 parts of CS 2 were used beforehand, based on the parts of the regenerated cellulose filaments produced, to derivatize the cellulose.

Example 4

Analogously to Example 3, to the solution of cellulose carbamate in 7% by weight of alkali, the solution of CX was added with stirring and a ratio of CC: CX of 33:67 was set, the final resulting cellulose concentration being 8.5% by weight and that of the alkali 7% by weight.

The low-viscosity spinning solution was after maturity (20h at 22 ° C) at a temperature of +5 ° C by means of a spinning pump to the spinneret (300 holes, 70μιη), which in a 40 ° C tempered aqueous spinning bath of 80 g / l

Sulfuric acid and 240 g / l sodium sulfate protruded, promoted. The coagulated filaments were drawn off by means of a nozzle draft of 0.7 and further in a stretching bath (stretching factor 1.15, 80 ° C, 20 g / l H ₂ S0 ₄ ) and then the laundry (60 ° C, distilled water) fed before this is dried isometrically at 80 ° C with the help of dry palettes and finally wound up as filament yarn.

The filaments thus produced had a tensile strength of 17 cN / tex, an elongation of 17% and a modulus of 890 cN / tex.

In order to produce the CX, 21 parts of CS ₂ were previously used, based on the parts of the regenerated cellulose filaments produced, to derivatize the cellulose.

Example 5 Analogously to Example 3, to the solution of cellulose carbamate in 7% by weight

Alkali the solution of the CX added with stirring and a ratio of CC: CX of 50:50 set, the final resulting cellulose concentration was 8.5% by weight and that of the alkali 7% by weight. The low-viscosity spinning solution was after maturity (20h at 22 ° C) at a

Temperature of +5 ° C by means of a spinning pump to the spinneret (300 holes, 70μιη), which in a 40 ° C tempered aqueous spin bath of 80 g / l sulfuric acid and 240 g / l sodium sulfate, promoted. The coagulated filaments were withdrawn by means of a nozzle delay of 0.7 and further in a stretching bath (stretching factor 1.33, 80 ° C, 20 g / l H2SO4) and then the laundry (60 ° C, distilled water) supplied before this dried isometrically at 80 ° C with the help of dry pallets and finally wound up as filament yarn.

The filaments thus produced had a tensile strength of 32 cN / tex, an elongation of 6% and a modulus of 1200 cN / tex.

To produce the CX, 15 parts of CS ₂ were previously used based on the parts of the generated Cellulosregene ratfilamente to derivatize the cellulose. Example 6

The procedure was as in Example 4 and made of the spinning solution at -2 ° C, a mixture with cotton fibers and sodium carbonate. 0.5 parts were added per 1 part of cellulose in the form of the dissolved cellulose derivatives

Cotton fibers and 9.3 parts Na ₂ C0 ₃ × 10H ₂ O. This mixture was coagulated at 100 ° C for 8 hours to form a sponge. The sponge was washed with water, neutralized with acid, washed again with glycerol-containing water and dried. After drying, the water absorption was determined. The sponge took up 125% of its dry weight

Water on.

Claims

claims

1. spinning solution, containing or consisting of cellulose and cellulose cellulose xanthate, the aforementioned substances being dissolved in a suitable solvent.

2. Dope according to one of the preceding claims, characterized in that the cellulose carbamate and / or the

Cellulose xanthogenate has a DP _CU oxam (determined according to SCAN-CM 15:99) of 150 to 750, preferably from 250 to 550.

3. spinning solution according to any one of the preceding claims, characterized in that the cellulose carbamate has a degree of substitution of carbamate (DP _Ca rbamat) of 0.1 to 1, preferably from 0.2 to 0.6.

4. spinning solution according to any one of the preceding claims, characterized in that the cellulose xanthate has a fresh Y value of 100 to 30, preferably 60 to 40.

5. spinning solution according to any one of the preceding claims, characterized in that the cellulosic solids content of the spinning solution of 4 to 15 wt .-%, preferably from 6 to 10 wt .-% is.

6. spinning solution according to any one of the preceding claims, characterized in that the spinning solution has a content

Cellulosecarbamat from 1 to 15 wt .-%, preferably from 2 to 8 wt .-% and / or

Cellulose xanthogenate from 1 to 15% by weight, preferably from 2 to 8% by weight

having. 2

7. spinning solution according to any one of the preceding claims, characterized in that the weight ratio of cellulose carbamate to cellulose xanthate from 5:95 to 95: 5, preferably from 60:40 to 85:15, particularly preferably from 65:35 to 70:30.

8. spinning solution according to any one of the preceding claims, characterized in that the solvent is selected from the group consisting of alkali liquors, in particular sodium hydroxide or potassium hydroxide solution, wherein preferably the concentration of alkali in the alkali hydroxide 4 to 12 wt .-%, preferably 5 to 10 Wt .-%, particularly preferably 6 to 9 Gew, -

% is.

9. spinning solution according to any one of the preceding claims, characterized in that they additionally spin aids, in particular inorganic spinning aids, such. Zinc oxide; organic spin agent, such as e.g. quaternary ammonium compounds; Alkyl ethers, e.g.

polyoxyethylene glycol; Contains sulfonated oils and / or mixtures thereof.

10. A process for producing a shaped body, in particular a filament, a bead, a sponge, a film of a spinning solution according to any one of the preceding claims, wherein the spinning solution by means of a shaping step in a molded body, transferred and during and / or after the shaping step, the solvent is removed from the molding.

11. The method according to the preceding claim, characterized in that filaments are produced, wherein a spinning solution according to one of the preceding claims by means of a spinneret to spun filaments and the filaments are introduced into a coagulation bath.

12. The method according to the preceding claim, characterized in that the coagulation bath water, as well as dissolved therein at least one component selected from the group consisting of inorganic 3

see acids, such as Sulfuric acid; Salts, e.g. Sodium sulfate; and organic liquids, e.g. Glycerin, includes or consists of.

13. The method according to any one of claims 10 to 12, characterized in that the spinning solution before the shaping step, in particular the spinning by dissolving the cellulose carbamate and the cellulose xanthate in the solvent freshly prepared and then ripened, wherein the tire preferably over a period of time from 1 to 72 hours, more preferably from 5 to 36 hours, particularly preferably 12 to 24 hours and / or at temperatures of the spinning solution of -10 to +50 ° C, preferably 0 to 30 ° C, particularly preferably 15 to 25 ° C is performed.

14. The method according to any one of claims 10 to 13, characterized in that the coagulation bath to a temperature of 10 to 90 ° C, preferably 20 to 70 ° C, more preferably 30 to 50 ° C is tempered.

15. The method according to any one of claims 10 to 14, characterized in that the filaments are supplied to a stretching bath after removal from the coagulation and stretched there, preferably with a stretching factor of 1.1 to 4, in particular 1.5 to 2.5 ,

16. The method according to the preceding claim, characterized in that the stretching bath contains an aqueous solution of an inorganic acid, in particular sulfuric acid and / or at temperatures of 50 to 99 ° C, preferably from 60 to 90 ° C, particularly preferably 75 to 85 ° C. is tempered.

17. The method according to any one of claims 10 to 16, characterized in that the filaments with a nozzle delay of 0.3 to 2.0, preferably 0.5 to 1.5, in particular 0.6 to 0.8 subtracted from the spinneret become.

18. The method according to any one of claims 10 to 17, characterized in that the resulting filaments are finally washed, in particular with water and / or dried.

19. Shaped body, in particular filament, pearl, sponge, foil, containing or consisting of cellulose carbamate and

Cellulose xanthate.

Shaped body according to the preceding claim, manufacturable or Herge provides by a method according to any one of claims 10 to 18.