WO2002097175A2

WO2002097175A2 - Cellulose-based material suitable for low-salt dyeing and printing providing high dyestuff yields and color fastness and for printing using an inkjet method and wet transfer printing

Info

Publication number: WO2002097175A2
Application number: PCT/EP2002/005858
Authority: WO
Inventors: Frank GÄHR; Frank Hermanutz
Original assignee: Deutsche Institute für Textil- und Faserforschung Stuttgart
Priority date: 2001-05-30
Filing date: 2002-05-28
Publication date: 2002-12-05
Also published as: DE10126244B4; DE50209491D1; AU2002319185A1; EP1399607B1; WO2002097175A3; DE10126244A1; ATE353989T1; EP1399607A2

Abstract

The invention relates to a method for the production of a cellulosic fiber or flat object by spinning or extruding a spinning or extrusion solution containing cellulose carbamate, which supplies cellulose materials containing carbamate groups, that provide high color shades, fixing yields and color fastness during dyeing or printing with dyes such as anionic textile dyes. The invention also relates to the cellulose materials produced according to the inventive method. The materials containing carbamate groups are also suitable for substantially reducing the salt additives required during dyeing, whereby a substantial improvement in waste water quality is achieved. The cellulose materials containing carbamate groups are also suitable for special printing methods such as printing with fiber reacting dyes using inkjet or wet transfer technology with high dyestuff yields.

Description

Cellulose-based material suitable for low-salt dyeing and printing in high color yields and fastness as well as for printing using the inkjet process and

Wet transfer printing

The invention relates to a process for producing a cellulosic fiber or sheet material containing carbamate groups, and to further processing, in particular by dyeing or printing. In addition, the present invention relates to cellulosic fiber or sheet-like structures produced by the method according to the invention and to their use as outer or undergarment material, lining material, upholstery material, technical textile, hygiene or medical fleece, sponge cloth and film. The cellulosic materials are suitable for significantly reducing the salt additives required for dyeing. This can significantly improve the quality of the wastewater and make it easier to reuse water through recycling. Furthermore, the cellulose materials are particularly suitable for special printing processes, such as printing with fiber-reactive dyes using inkjet or wet transfer technology in high color yields. A major disadvantage of the formulations used today for dyeing cellulose fibers (eg cotton, viscose) is the use of very high amounts of salt in order to achieve good fixing yields. For example, in reactive dyeing using the exhaust method, an average of approx. 50 g / 1 sodium chloride or sulfate is still added to the dye liquors. For this reason, salt consumption in reactive dyeing is estimated at 1.8 million tons per year worldwide. Disadvantages in the printing area are the relatively long machine set-up times with conventional printing processes (film or rotary printing), unsatisfactory transferability of sample prints to production, the low flexibility and, especially when printing with reactive dyes, the high wastewater load and the accumulation of residual pastes that are disposed of have to. There has been no shortage of attempts to establish new printing processes which do not have various of the disadvantages outlined. Ink-jet printing, which is particularly interesting for sample prints, is currently under development, further advanced and partly in production are systems for wet transfer printing. A problem that has not yet been solved satisfactorily both in wet transfer printing and in inkjet printing on cellulosic materials is the insufficient dye yield.

The steps in wet transfer printing with fiber-reactive dyes are the printing of a design on a specially coated paper using rotary film printing, intermediate drying and possible storage of the printed paper, contacting this printed paper with a moist web of cellulose material, which is usually impregnated with some fixing alkali. In this last step, the fiber-reactive dye is transferred from the paper to the textile containing cellulose fibers. In both steps, i.e. Both when printing on the paper and when transferring the dye to the textile, yield losses result from hydrolysis of the reactive dye or from incomplete transfer of the dye from the paper to the textile. In the first step approx. 10 to 15% of the dye is lost, in the second step approx. 20 to 30%. Overall, the fixing yield in wet transfer printing with fiber-reactive dyes is 60 to 65%, which is not an improvement compared to established printing processes. It would therefore be of great advantage if, in particular in the second step, the dye transfer from paper to the textile goods, a significant improvement in the fixing yield was achieved.

Ink jet printing uses only a fraction of the amount of dye compared to conventional direct printing. For this reason, dark shades are very difficult to achieve. The pressure drop is heavily dependent on the substrate, especially with ink-jet printing. In practice, the respective goods are therefore especially impregnated with certain substances. In order to improve the print quality, the impregnation of the printed matter with thickeners or quaternary nitrogen compounds is recommended in several patents (EP 534660, US 4702742, JP 268372). This pretreatment and impregnation of goods is based on empirical values and does not currently represent a satisfactory solution to the problem. It would be a great help if instead of pure cellulosic base materials such as cotton or viscose, better and deeper dyeable substrates based on cellulose were available. The object of the present invention is therefore to provide a process for the production of a cellulosic fiber or sheet material with high affinity for dyes and high absorption capacity for dyes, so that as little dye as possible is lost through chemical hydrolysis or transfer losses. The resulting colored or printed substrates should have high fastness properties (wash, light and rub fastness). According to a further object of the invention, these cellulose-based materials must be able to be produced by the processes customary in the textile industry. The chemicals used to manufacture these materials are said to be inexpensive. In addition, a further object of the invention is to provide fiber and flat structures produced by the method according to the invention and to propose an advantageous use thereof.

The object is achieved according to the invention by a process for producing a cellulosic fiber or sheet by spinning or extruding a cellulose-carbamate-containing spinning or extrusion solution, in which the carbamate groups in the cellulosic fiber or sheet not after the spinning or extrusion process be completely hydrolyzed. The process according to the invention gives fibrous or sheetlike structures which are particularly suitable for textile uses and which, when dyeing, in particular with anionic textile dyes, provide high color depths, fixation yields and fastness properties.

The process is preferably carried out in such a way that the cellulose carbamates produced contain 0.02 to 0.85, in particular 0.03 to 0.31, carbamate groups per anhydroglucose unit after the spinning or extrusion process, corresponding to nitrogen contents of 0.17 to 6% by weight. -%, in particular 0.23 to 2.5 wt .-%.

The cellulose carbamate starting material is preferably produced by the process described in DE 196 35 707, in which a small amount of inclusion cellulose containing a solvent is reacted with a urea melt. The fibrous cellulose carbamate starting material typically has nitrogen contents of 2.0 to 6.0%, depending on the synthesis conditions. For this Cellulose carbamate solutions are produced which preferably have a concentration of 7 to 12% by weight, based on α-cellulose. This can be done, for example, by dissolving the cellulose carbamate in about 1 to 10% by weight, in particular about 4% by weight. -%, sodium hydroxide solution. In a preferred embodiment, this solution is processed into a fibrous or sheet-like structure by a wet spinning or wet extrusion process from an alkaline solution, in which the solution is introduced into a precipitation bath through a corresponding spinneret or extrusion opening. The precipitation bath preferably contains a dilute acid, in particular dilute sulfuric acid. Alternatively, a lower alcohol, in particular methanol, can be used in the precipitation bath (coagulation bath) according to the method described in Lenzinger reports 59 (1985), 111-117, which likewise triggers precipitation (coagulation) of the polymer. In a preferred embodiment, the alcohol is selected such that the alcohol required for the production of the inclusion cellulose and the alcohol used as the precipitation medium are identical, so that recovery of the alcohol, in particular by destiUative processes, and also recovery of the alkali used is facilitated and is practicable at low cost.

In contrast to previously known spinning and extrusion processes for cellulose carbamate, in which complete saponification of the carbamate groups is carried out immediately after the spinning or extrusion process (usually by the action of 60 ° C. warm 1 N sodium hydroxide solution), the process according to the invention is followed no or only incomplete saponification of the carbamate groups at the precipitation bath. The products of the process according to the invention are therefore not cellulose regenerate products in the actual sense, but rather cellulose derivative products.

The acid carried along from the precipitation bath is advantageously removed by washing out in a bath with a weakly alkaline, aqueous medium, in particular in an aqueous medium containing hydrogen carbonate. The fiber structure obtained according to the invention preferably becomes a woven fabric,

Knitted or nonwoven processed. Such materials have not previously been used for dyeing and textile printing. Surprisingly, the fiber or sheet-like structures containing carbamate groups have highly affine properties with respect to reactive dyes, as a result of which dyeings and prints are obtained in a previously unknown quality. It has been found that a high content of carbamate groups leads to a high affinity of the material for textile dyes. This means that a high degree of substitution leads to high achievable color yields or color depths. In a preferred embodiment, the cellulosic fiber or flat structures or the woven, knitted or nonwoven fabrics produced therefrom are subjected to dyeing or printing.

A particular advantage of the process is that the dye solutions used do not have to have a high electrolyte content, as a result of which the waste water quality and the possibility of water recycling are significantly improved. Particularly good results are achieved when using anionic textile dyes. A particularly preferred embodiment consists in the use of fiber-reactive dyes with which very high color yields can be achieved. A reactive dye solution is preferably used which has a salt concentration of less than 35 g / 1, in particular less than 15 g / 1, for standard reactive dyes (for example CI Reactive Red 158) and less than for reactive dyes which are difficult to fix (for example CI Reactive Blue 21) 50 g / 1, in particular less than 25 g / 1. It has also been shown that printing on the cellulosic fiber or flat structures by inkjet printing or wet transfer printing leads to particularly good results. The present invention furthermore relates to cellulosic fiber or sheetlike structures produced by the preceding method and their use, in particular as outer or undergarment material, lining material, cover material, technical textile, hygiene or medical fleece, sponge cloth and film.

The process described for the production of cellulosic fiber or flat structures by spinning or extruding a cellulose-containing spinning or extrusion solution is clear compared to the processes described so far

Advantages on. For example, doing without the process-related saponification step leads to significantly lower costs. Dyeing tests show that ordinary dyes, such as anionic textile dyes and in particular fiber-active dyes, have a high affinity for these carbamate materials. The carbamate materials produced by the process claimed according to the invention are therefore very well suited to achieving dyeings and prints in high depths of color and yields. Very brilliant colors are obtained. With regard to color fastness, the surprisingly good light fastness and the wet rub fastness, which is significantly improved compared to normal viscose, are particularly noteworthy. The amount of salt required in dyeing liquors can be greatly reduced. These properties make these materials particularly suitable for printing with fiber-reactive dyes using the inkjet and wet transfer processes.

The invention will be explained in more detail using the following examples, without being restricted to these.

Example 1:

4 kg of alkali cellulose (average degree of polymerization (DP): 388) are rinsed with 22 l of methanol, pressed off and reacted in a heatable kneader for 2 hours in a 133 ° C. hot urea melt (2.5 kg of urea) to give the cellulose carbamate. The cellulose carbamate has a nitrogen content of 2.9%, corresponding to a DS of 0.37. It is washed and dissolved to produce the spinning solution directly in cold 8% by weight sodium hydroxide solution, so that the final concentration of the alkali in the finished solution is 4% by weight. The cellulose carbamate content of the Spirm solution is 9.6% by weight, based on alpha-cellulose. The spinning solution is spun at 5 ° C. in a precipitation bath with 10% sulfuric acid (room temperature), washed in a further bath which has been made slightly alkaline by hydrogen carbonate, then washed again in a water bath and wound onto a bobbin. The thread take-off speed was 72 m / min, number of individual filaments: 40, titer: 110 dtex, nitrogen content: 1.5%, DS 0.18. On knitted fabric made from this was both with the easily fixable reactive dye

C.I. Reactive Red 158 as well as with the difficult to fix fiber-reactive turquoise dye C.I. Reactive Blue 21 dyed after the pull-out procedure in a lockable staining cup made of stainless steel.

Fleet ratio: 1:20

Dye concentration: 3%

Glauber's salt: variable (see tables 1 and 2)

Dyeing temperature: 40 ° C for C.I. Reactive Red 158 80 ° C for C.I. Reactive Blue 21

Heating rate: 1.5 ° C

Add alkali 30 min after reaching the dyeing temperature: Reactive Red 158: 20 g / 1 soda

Reactive Blue 21: 15 g / 1 soda and 1.5 ml / 1 sodium hydroxide solution 32.5% by weight staining time from the addition of alkali: 60 min

For comparison, a knitted fabric made of textile viscose was dyed according to identical conditions.

The degrees of exhaustion (Table 1 and 2) were determined photometrically.

On dye series with C.I. Reactive Red 158 (see recipe above) was further determined by light exposure according to DIN 54004 by exposure to a Xenotest 450 System Cassella exposure device for 168 hours. For comparison, the light fastness obtained for identical dyeings on mercerized cotton (CO), modal (MOD) and lyocell (CLY) fabrics and for knitted fabrics made of viscose (CV) and cellulose carbamate (CC1) are compiled in Table 3.

Table 4 shows the wet rub fastness for dyeings with CI Reactive Red 158 (3% dye concentration) on cellulose carbamate (CC1) and viscose (CV). The wet fastness properties were determined in accordance with DIN EN ISO 105 X12. Table 4 shows the comparison between CC1 and CV. Example 2:

Analogously to Example 1, cellulose carbamate with a nitrogen content of 3.1% by weight, corresponding to a DS of 0.40, was produced by extending the reaction time to 3 hours with otherwise identical synthesis parameters. From this cellulose carbamate, as in Example 1, spun threads were produced which had a nitrogen content of 1.75% by weight. These filaments were processed into a fabric (CC2) with a square meter weight of 124 g. The fabric was impregnated with a solution which contains 3% by weight of sodium hydrogen carbonate and 10% by weight of urea and was dried for 5 minutes. Using a Piezo (DOD) ink jet printer from Mimaki, this material is produced in the colors black, turquoise, blue, red, orange and yellow, which were taken from the Cibacron range (salt-free) from Ciba-Geigy , printed. The printing inks are characterized by the following parameters: pH 7.7; Conductivity 3.7 mS / cm; Surface tension 51.3 mN / m; Viscosity approx. 1 mPas.

The pressure is fixed in saturated steam at 102 ° C for 10 minutes. The

Tissue is rinsed twice with hot water at 95 ° C and once with cold water. For comparison, a fabric made from normal viscose was treated, printed and washed according to identical conditions. Table 5 shows the color depth obtained for the 6 different colors based on the K / S values. In particular, the colors yellow and red appear much more brilliant on CC2 compared to CV.

Example 3:

The staple fibers of cellulose carbamate obtained in Example 2 are saponified by treatment with 2% by weight sodium hydroxide solution at a temperature of 60 ° C. to a nitrogen content of 0.24% by weight, corresponding to a DS of 0.03. These filaments were processed into a fabric (CC3) with a square meter weight of 120 g. The fabric was impregnated with a solution containing 3% by weight sodium hydrogen carbonate, 10% by weight urea and 0.5% by weight sodium borohydride, 5 minutes intermediate dried and printed as in Example 2. The pressure is fixed in saturated steam at 102 ° C for 10 minutes. The fabric is washed twice with hot water at 95 ° C and once with cold water. Table 6 shows the color depth obtained for each of the 6 different colors using the K S values in comparison to viscose fabric, which was impregnated and printed using an analogous process.

Example 4:

The fabric made of cellulose carbamate CC 2 produced according to Example 2 was printed with CI Reactive Blue 21 by the wet transfer process. In a first step, a paste was prepared that contained a thickener and 10 parts of CI Reactive Blue 21 liquid dye. The proportion of thickener was chosen so that a paste viscosity of 2000 mPa s with a shear rate of 10 s ^"1 resulted. The paste was left to swell overnight in the refrigerator, 5 parts (based on the weight of the paste) sodium hydrogen carbonate and 0. 5 parts of sodium borohydride were added and the mixture was briefly stirred again.This color paste was printed onto a coated, basic gp paper using a 125-mesh rotary stencil and a 1 cm roller doctor blade at a printing speed of 60 m / min the transfer of color was determined spectrophotometrically for the transfer prints, pretreated cotton fabric (135 g / m ² ) or fabric made of cellulose carbamate according to Examples 1 and 2. The two fabrics were each impregnated with 5% strength by weight sodium hydroxide solution and by means of a padding machine squeezed to a moisture content of 60%. The transfer printing was done with the help of the transfer paper by pressing the Pa piers on the fabric at the foulard. The transfer prints were fixed for 16 hours at room temperature in the manner of the block-cold retention process. For after-washing, the liquor ratio was 1:20, cold 2 times for 20 minutes and then 2 times 20 minutes at 95 ° C. with demineralized water. Table 7 shows the printing results based on the K / S values, the degree of exhaustion, the amount of dye transferred to the respective fabric [%] and the printing. Example 5:

Analogously to example 1, a cellulose carbamate (nitrogen content 2.9% by weight) was produced, washed and, likewise analogously to example 1, a spinning solution was prepared. The spinning solution is spun at room temperature in a coagulation bath containing ordinary technical methanol. The thread is then washed and processed as in Example 1. The nitrogen content of the carbamate thread (CC4) was 2.1%, corresponding to a DS of 0.26. A knitted fabric made from this was made with the difficult to fix fiber-reactive turquoise dye C.I. Reactive Blue 21 dyed using the pull-out method in a sealable stainless steel staining cup. For comparison, a knitted fabric made of textile viscose was dyed according to identical conditions. Liquor ratio: 1:20 dye concentration: 3% Glauber's salt: 10 g / 1

Dyeing temperature: 80 ° C for C. I. Reactive Blue 21

Heating rate: 1.5 ° C alkali addition 30 min after reaching the dyeing temperature: 15 g / 1 soda and 1.5 ml / 1 sodium hydroxide solution 32.5% by weight

Staining time from alkali addition: 60 min

Table 8 shows the color depths obtained, degrees of exhaustion [%] and lightfastness notes for the corresponding dyeings on viscose (CV) and cellulose carbamate (CC4).

Table 1: Degree of exhaustion for 3% staining with C.I. Reactive Red 158 depending on the amount of salt added to viscose (CV) and cellulose carbamate (CC1)

Table 2: Degree of exhaustion [%] for 3% staining with C.I. Reactive Blue 21 depending on the amount of salt added to viscose (CV) and cellulose secarbamate (CC1)

Table 3: Lightfastness of dyeings with C.I. Reactive Red 158 (3% staining concentration) on various substrates

Table 4: Wet rub fastness notes of dyeings with CI Reactive Red 158 (3% dye concentration) on cellulose carbamate (CC1) and viscose (CV)

Table 5: K / S values for 6 different reactive dyes in ink-jet printing on viscose (CV) and cellulose carbamate (CC2)

Table 6: K / S values for 6 different reactive dyes in ink-jet printing on viscose (CV) and cellulose carbamate (CC3)

Table 7: Dependency of the printing result for wet transfer printing with CI Reactive Blue 21 on the printed cellulosic tissue material

Table 8: Color depths, degree of exhaustion [%] and light fastness rating for 3% staining with C.I. Reactive Blue 21 on viscose (CV) and cellulose carbamate (CC4)

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Claims

claims

1. Process for the production of a cellulosic fiber or sheet by spinning or extruding a spinning or extrusion solution containing cellulose carbamate, characterized in that the carbamate groups in the cellulosic fiber or sheet are not completely hydrolyzed after the spinning or extrusion process.

2. The method according to claim 1, characterized in that 0.02 to 0.85 carbamate groups per anhydrogluccose unit remain in the cellulosic fiber or fabric.

3. The method according to claim 2, characterized in that 0.03 to 0.31 carbamate groups per anhydroglucose unit remain in the cellulosic fiber or sheet.

4. The method according to at least one of the preceding claims, characterized in that the spinning or extrusion is carried out by a wet spinning or wet extrusion process from an alkaline spinning solution.

5. The method according to at least one of the preceding claims, characterized in that the spinning or extrusion is carried out using a precipitation bath with dilute acid or a lower alcohol.

6. The method according to at least one of the preceding claims, characterized in that the cellulosic fiber or fabric is washed after the spinning or extrusion process in a weakly alkaline bath.

7. The method according to claim 6, characterized in that as a weakly alkaline

Bad a hydrogen carbonate bath is used.

8. The method according to at least one of the preceding claims, character- ized in that the cellulosic fiber structure to a fabric, knitted fabric or

Nonwoven is processed.

9. The method according to at least one of the preceding claims, characterized in that the cellulosic fiber or fabric, fabric, knitted or nonwoven is subjected to a dyeing.

10. The method according to at least one of the preceding claims, characterized in that the cellulosic fiber or flat structure, fabric, knitted fabric or nonwoven is subjected to printing.

11. The method according to claim 10, characterized in that the printing is carried out by inkjet printing.

12. The method according to claim 10, characterized in that the printing is carried out by wet transfer printing.

13. The method according to any one of claims 9 to 12, characterized in that an anionic textile dye is used for dyeing or printing.

14. The method according to at least one of claims 9 to 13, characterized in that a dye with a fiber-reactive group is used for dyeing or printing.

15. The method according to claim 14, characterized in that the dyeing is carried out with a dye solution which has a salt concentration of less than 50 g / 1.

16. The method according to claim 14, characterized in that the dye solution has a salt concentration of less than 25 g / 1.

17. Cellulosic fiber or sheet material, woven fabric, knitted fabric or nonwoven fabric, obtainable according to at least one of the preceding claims.

18. Use of the fibrous or flat structure, fabric or knitted fabric according to claim 17 as outer or undergarment fabric, lining fabric, upholstery fabric, technical textile, hygiene or medical fleece, sponge cloth and film.

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