PT91845B - PROCESS FOR THE TINTING OF TEXTILE MATERIALS MADE OF CELLULOSE FIBERS - Google Patents

Abstract

Process for dyeing textile materials from cellulose fibres in an alkaline aqueous medium with vat dyes in the presence of reducing agent mixtures of a) sodium dithionite and/or thiourea dioxide and b) alpha -hydroxycarbonyl compounds in a weight ratio of 1:1 to 1:15 at a pH of at least 13 and at temperatures of above 75 DEG C and finishing the dyeings in a conventional manner. The dyeings obtained are very level.

Description

During the dyeing of textile materials that are made of cellulose fibers or contain cellulose fibers mixed with synthetic fibers, with vat dyes, work in an alkaline-aqueous medium in the presence of reducing agents and, possibly, other substances usual auxiliaries at temperatures of, for example, 45 to 60 ° C and then dyeing is done by rinsing, oxidizing and soaping the textile material. The best known reducing agents used in cell dyeing for textile materials containing cellulose fibers are sodium dithionite, thio-urea dioxide (formamidine sulfinic acid) and hydroxyacetone. Thus, for example, from the patent DE-OS 20 11 587 it has become known to use thiourea dioxide as a reducing agent for tub dyeing of textiles containing cellulose fibers. As it has become known, moreover, from this publication, the reduction of vat dyes can be carried out additionally in the presence of glucose, to prevent sensitive dyes from being reduced in excess. According to the data cited in the examples, glucose is used in a reduced proportion, relative to the amount of thio-urea dioxide. The uniformity of the dyeings in the vat, which are thus obtained, needs, however, an improvement.

From the DE-PS 2 164 465 patent, a process for dyeing and printing textile materials with vat dyes has become known, whereby the vat dyes are reduced in aqueous media, with a pH value of at least 12, with acetone hydroxide in the presence of quinoid compounds, which are soluble in water under dyeing conditions. In this case, a disadvantage is that the quinoid compounds must be used together and the number of vat dyes appropriate for

te process is limited.

The purpose of the present invention is to provide a process for dyeing textile materials, which consist of cellulose fibers or contain cellulose fibers mixed with synthetic fibers, in an alkaline aqueous medium with vat dyes in presence of mixtures of reducing agents, and for the finishing of dyeings, in which dyes with better uniformity are obtained, than in known dyeing processes.

The objective is achieved according to the invention by the fact that, as mixtures of reducing agents, combinations of:

a) sodium dithionite and / or thio-urea dioxide, and

b) alpha-hydroxy-carbonyl compounds, in a weight ratio of 1: 1 to 1:15 β, the dyeing is carried out at pH values of at least 13, as well as at temperatures above 75 ° C.

Textile materials are made of cellulose fibers or contain cellulose fibers in a mixture with other fibers. They can be in any form of processing, for example as flakes, card tape, yarn, strip, fabrics or knits. In the case of cellulose fibers, it can be treated with either natural cellulose or regenerated cellulose, such as cellulosic wool or polynosic fibers. The action process:? According to the invention, it is especially suitable for dyeing mercerized cotton, raw cotton, as well as for dyeing raw yarns, which are in the form of a strip or cross bobbin. Synthetic fibers, which are mixed with cellulose fibers in textile materials, are for example polyester fibers or synthetic polyamide fibers. Natural or regenerated cellulose fibers are dyed with vat dyes. In the case of vat dyes,

these are mainly anthraquinoid dyes and indigestion. The dyes can be, for a long time, obtained in the market and are documented in the Color Index, see Color Index, 3rd edition ^â · 1971 »Volume 3, pages 3719 ~ 3844 and Volume 4, CI n2.58000-74000 , Society Dyers and Colorists, In glaterra.

The processes for dyeing cellulosic fibers with vat dyes in the presence of mixtures of reducing agents have already been treated above, regarding the current state of the art. Regarding the textile material, it is necessary, for this case, from 0.01 to 10% by weight of vat dye, or of a mixture of several vat dyes. The dyeing of textile materials can take place, for example, in a long heated bath, with a bath ratio of 1: 5 to 1:40, preferably between 1: 8 and 1:20, or also in a continuous process, for example. example the impregnation process. In this case, bath proportions are used from 1: 0.5 to 1: 3 · According to the invention, the reduction of the vat dyes takes place in an aqueous medium, with pH values of at least 13 and with lists of reduction agents consisting of

a) sodium dithionite and / or thio-urea dioxide (formamidine-sulfinic acid)

b) alpha-hydroxy-carbonyl compounds, in a weight ratio between 1: 1 and 1:15, at temperatures above 75 ° C.

As component a) of mixtures of reducing agents, sodium dithionite, thio-urea dioxide or mixtures of sodium dithionite and thio-urea dioxide are used in any desired proportion. As component a), sodium dithionite is preferably used.

As component b) of mixtures of reducing agents, alpha hydroxy compounds

-nanhorri it. Suitable alpha-hydroxy-carbonyl compounds are, for example, monohydroxy-acetone (hereinafter referred to as hydroxyacetone ' ¹ ), dihydroxy-acetone, glycolic aldehyde, dl hydroxy-butanone, the 2,3 ~ iihydroxy-acryl-aldehyde known as triosis -reducton, ascorbic acid and cyclopentene-diol-2,3-one-l. The compounds of this type are called reductones and reductonates. Other examples of compounds of this type are triose-reducton and reducing acid, which is obtained, for example, through the decomposition, acidic or alkaline, of glucose, saccharides or polysaccharides, such as starch, molasses and pectin. Of this group of reducing agents, hydroxy-acetone is preferably preferred. It is also possible, of course, to use mixtures of various alpha-hydroxy-carbonyl compounds as component b) of the combinations to be employed according to the invention, for example hydroxyacetone and glucose mixtures.

Preferably, as a mixture of reducing agents, a combination formed by:

a) sodium dithionite, and

b) hydroxyacetone in a weight ratio of 1: 2 to 1:10. Dyeing is carried out at pH values of at least 13. For this purpose, unlike those dyeing processes, in which sodium dithionite is used as the only reducing agent, a greater amount of an alkali is used. The pH value of the aqueous dyeing medium is regulated, preferably, by adding sodium chlorine to the bath. Other bases can also be used, for example potassium bleach. A pS value of at least 13 is achieved by adding at least 20 ml for each liter of the bath in 38 ° B sodium chloride, preferably more than 25 ml / liter of 38 ° sodium sodium chloride. Textile materials are introduced, for dyeing

I

in an aqueous-alkaline bath, containing the vat dye and mixtures of reducing agents to be employed according to the invention, and, where appropriate, other usual dyeing auxiliary agents. The textile material is reached in the bath at temperatures above 75 ° β to 120 °, preferably between 80 ° and 105 ° · As dyeing temperatures above 100 ° C must be applied, the weave is applied. performed on the pressure devices that are usual for this. In these conditions, the vat dyes become soluble and spread over the textile material. The dyeing time is about $ 0 to 120 minutes. Mixtures of reducing agents are used in quantities of 1 to 20, preferably 2 to 10 grams per liter, in the baths.

textile material which, after treatment in the dyeing bath, contains the tub dye in the leuco form, is then treated in the usual way, in order to complete the dyeing. For this purpose, the textile material is first oxidized according to the usual dyeing processes in vats. After oxidation, the textile material is rinsed and soaped. Finishing of the dyeings can also be carried out, so that the textile material, which contains the tub dye in the form of leuco, is first rinsed, then oxidized and then soaped.

The process according to the invention can, of course, also be carried out in the presence of the usual sizing agents for dyeing in the vat, for example, in the presence of polyvinyl-pinolidone or water-soluble polyamides, which are already known for example since DE-PS 1 125 881. During the dyeing of textile materials made from mercerized cotton or raw cotton, it is additionally used as auxiliary dyeing agents, homopolymerized from acrylic acid or copolymerized methacrylic acid from acrylic acid or acid methacrylic

other monomers, for example methacrylamide, acrylamide, ac: lonitrile, methacrylonitrile, acrylic acid ester, methacrylic acid ester, as well as maleic acid, plus 03 alkali or ammonium salts of copolymers or homopolymers containing carboxyl groups . In addition, copolymers made of maleic acids and styrene, maleic acid and vinyl esters or maleic acid and vinyl ethers are suitable. The polymers of interest have viscosities (measured with 0 ball drop viscometer according to HBppler, at 20 ° C, according to DIN 53 015) from 1 to 500 mPas in aqueous solution and at 7.5% by weight, which is regulated to a pH value of 9 with sodium chloride. The use of such polymers in vat dyeing in amounts of 0.05 to 2% by weight relative to the dyeing material is already known from DE-PS 2 444 825.

The advantages of the process according to the invention consist in a better uniformity of the textile materials that contain dyed cellulose fibers. This refers, in particular, to those textile materials, which are difficult to dye :? evenly, such as mercerized cotton, in particular mercerized cotton yarn in the form of a cord or cotton thread in particularly large bobbins (eg, bobbins with more than 1200 g of thread). In addition, in comparison with the known reducing agent mixtures, uniform dyes are obtained with vat dyes or vat dye combinations, in which special uniformity problems occur in the dyed materials. Another advantage of the process according to the invention is that wastewater pollution from textile processing requires less treatment than the isolated use of sodium dithionite and thiourea dioxide.

The parts indicated in the examples are parts in weight, the indications in percent, are percentages by weight.

EXAMPLE 1

A yarn of mercerized cotton yarn is pre-crosslinked initially in a yarn dyeing apparatus usual on the market, so the article is treated with 3 g / 1 of a diethylhexyl ester and phosphoric acid, as a crosslinker, for 15 minutes at room temperature, under constant pumping of the dyeing bath in the dyeing apparatus. The cross-linked yarn, made of mercerized cotton, is then dyed in a 1:20 proportion bath, at

* 100 C, and the bath has the following composition:

part of the vat dye, C.I. 69825, blue, parts of the 38 ° Bé aqueous sodium hydroxide solution, parts of sodium dithionite, parts of hydroxy-acetone, part of sodium polyacrylate (molecular weight 60,000) 952 parts of water.

bath is heated to 100 ° C for 30 minutes. Dye for 45 minutes at 100 ° C, then cool and dye ready as usual. A yarn of yarn dyed blue is obtained, uniformly, with a good penetration of the dyeing and very good purities.

The good uniformity of the dyeing within the yarn and between the different yarns can be clearly recognized when knitted pieces are produced with the yarn of a yarn and with a yarn of different yarns.

EEEUPLO 2

A raw cotton yarn is treated in a usual dyeing apparatus on the market, with cross bobbins, with an aqueous bath, which contains 3 g / liter of diethylhexyl ester and

phosphoric acid as a crosslinker for 15 minutes at room temperature under a permanent pumping of the aqueous medium. The end thus reticulated, made of raw cotton, is next :. dyed in a bath with a 1:15 ratio and which has the following composition:

0.8 parts of the CI 69525 »vat dye olive green, parts of 38 ° Be aqueous sodium chloride, part of sodium dithionite, parts of hydroxy-acetone, part of sodium polyacrylate, with a viscosity of 35 mPas ( 30% aqueous solution, at 20 ° C),

963.2 parts of water.

After the bath described above has been heated to 60 ° C, the bath is pumped for 10 minutes at 60 ° C. Then, the bath is heated under a permanent pumping for a period of 15 minutes, to 90 ° C and the textile material is dyed for 40 minutes at 90 ° C. Then, the bath is cooled to 60 ° C and the dyeing is primed as usual, namely rinsing with water, oxidation with 1 ml / 1 of 40% hydrogen superoxide and the soapy boiling with a bath that contains 0.5 g / l of an addition product of 25 moles of ethylene oxide in 1 mole of a fatty alcohol in ^C 12 ^C 18 ·

A uniform gray-olive gray textile material is obtained, with very good penetration and good resistance. The good uniformity of the dyeing in crosshead coil was clearly evidenced by the fact that mesh pieces were produced, in which the inner layers of the threads and the outer layers of the threads of a crosshead coil were interlaced in a mesh. In this case, no

differences in tone and intensity of tone between the outer and inner layers of the threads

EXAMPLE 5

Cotton weft articles ready for dyeing, were dyed in a usual dyeing machine, with closed pumps, which were activated during the entire dyeing process, in an aqueous bath, which contained the following components:

0.5% of the orange colorant, C.I. 69025, and

0.5% of the C.I. 59800 blue vat dye (relative to the weight of the dry cotton weft article), ml / 1 of aqueous sodium hydroxide solution (58 ° Bé),

0.5 g / l sodium chlorite, and 5 g / l hydroxy-acetone.

The proportion of the bath was 1:20. The bath was heated to 60 ° C. At this temperature, only half of the dyeing material was initially operated and the second half was added five minutes later. The two pieces of fabric were then fully dyed together with permanent activation of the pumps, while the bath was heated to 80 ° C for 10 minutes and then remained at 80 ° C for 50 minutes. Then, dyeing was done in the usual way, in which the fabric was washed with water, oxidized with 1 ml / 1 of hydrogen superoxide and soaped, at 90 to 100 ° (with a commercial rinsing agent.

The two 5 β 4 · dyes, used for dyeing, have a different migration capacity and spread quickly differently.

So it was not expected that the piece of fabric

of what was added later corresponded to the piece of fabric that was in the dyeing bath from the beginning, in terms of color tone and intensity. However, the example demonstrated that the two pieces of fabric were dyed to an almost equal color and, therefore, good uniformity had been achieved.

EXAMPLE 4

Example 3 was repeated, with the exception that the bath now contained, instead of the amounts of sodium hydroxide solution indicated in Example 3, sodium dithionite and hydroxy-acetone in the following amounts:

ml / c aqueous sodium hydroxy solution, 38 ° C,

0.5 g / 1 of sodium dithionite and

3.5 g / 1 hydroxy-acetone.

Two tintings were obtained in the taci pieces, which were barely distinguishable in terms of color depth and tone. Even in these unfavorable dyeing conditions, good uniformity was obtained.

Comparison example 1:

The dyeing recipe of Example 3 was repeated with dyes 3 and 4, with the exception that the aqueous bath - as in the usual processing according to the IN process - contained 12 ml / 1 of aqueous hydroxy solution of sodium at 38 ° Be and 3 g / 1 of sodium dithionite as the only reducing agent. In this operating mode, pieces of fabric are dyed in a distinctly different way. The piece of fabric added afterwards was dyed with a distinctly lighter and less intense blue color.

Comparison example 2:

The operational form indicated in Example 3 was repeated with the exception that, again, the dyeing bath contained 2.5 g / 1 of sodium dithionite and 0.5 g / 1 of hydroxy-acetone. The amount of sodium hydroxide solution remained the same. With this operational form, two pieces of fabric were dyed in a clearly uneven manner. The piece of fabric added later had a distinctly lighter and less deep blue color.

Comparison example 3:

The procedure indicated in Example 3 was repeated with the exception that 20 ml / 1 of a 38 ° B aqueous sodium hydroxide solution, 2.5 g / 1 of sodium bicarbonate and 2 g / 1 of hydroxy-acetone. Also obtained in this case were two pieces of fabric that were dyed in a different way, of which the piece of fabric added later is dyed with a lighter and less deep blue color.

Claims (2)

£ 1. - Process for dyeing textile materials that are made of cellulose fibers or contain cellulose fibers mixed with synthetic fibers, in an alkaline aqueous medium with vat dyes in the presence of mixtures of reducing agents and finishing agents of the characterized dyeing because mixtures of reducing agents are used as mixtures of reducing agents a) sodium dithionite and / or thio-urea dioxide, and b) alpha-hydroxycarbonyl compounds, in a weight ratio between 1: 1 and 1:15, θ the dyeing must be carried out at pH values of at least 15, as well as at temperatures above 75 ° C. 2§. Process according to claim 1, characterized in that combinations of a) sodium dithionite and b) hydroxyacetone, weight ratio from 1: 2 to 1:10.