Continuous process for the simultaneous high grade finishing and dyeing of cellulosic piece goods
United States Patent 3893804
Process for the simultaneous high-grade finishing and dyeing with leuco esters of vat dyestuffs of piece-goods of cellulose fibres and mixtures thereof with synthetic fibres, preferably linear polyester fibres, in a continuous working method, wherein the textile material is impregnated at room temperature with an aqueous bath which contains, besides leuco esters of vat dyestuffs, aminoplast-precondensates which may be hardened in the heat and/or reactant resins which act to give cross-linking effects with the cellulose fibre, together with condensation catalysts acting simultaneously as acid donators, the material thus treated is dried and then subjected to the action of dry heat at 150° to 230°C.
US Patent References:
Process for simultaneously stabilizing and applying a vat dye to textile material comprising regenerated cellulose
Walmsley et al. - February 1953 - 2628151
/3576589.html
Coon - April 1971 - 3576589
Process for simultaneously stabilizing and applying a vat dye to textile material comprising regenerated cellulose
Walmsley et al. - February 1953 - 2628151
/3576589.html
Coon - April 1971 - 3576589
Inventors:
Hepp, Josef (Frankfurt am Main, DT)
Lehmann, Joachim Walter (Kelkheim/Taunus, DT)
Lehmann, Joachim Walter (Kelkheim/Taunus, DT)
Application Number:
05/334834
Publication Date:
07/08/1975
Filing Date:
02/22/1973
View Patent Images:
Export Citation:
Assignee:
Hoechst Aktiengesellschaft (Frankfurt am Main, DT)
Primary Class:
Other Classes:
8/918, 8/651, 8/629, 8/532, 8/586, 8/585
International Classes:
D06P1/22; D06P1/56; D06P1/62; D06P3/60; D06P3/82; D06P1/00; D06P1/44; D06P3/58; D06P1/30
Field of Search:
8/17,35
Other References:
Fortess et al., American Dyestuff Reporter, May 27, 1963, pp. 403-411, TP 890 A 512..
Primary Examiner:
Levy, Donald
Attorney, Agent or Firm:
Curtis, Morris & Safford
Claims:
We claim
1. A continuous process for the simultaneous highgrade finishing and dyeing of piece-goods of cellulose fibres and mixtures thereof with linear polyester fibres, with leuco esters of vat dyestuffs wherein: the textile material is impregnated at room temperature with an aqueous bath which contains (1) a leuco ester of a vat dyestuff; (2) an aminoplastprecondensate which may be heat hardenable and/or a reactant resin selected from the group of cyclic urea derivatives consisting of methylol-ethylene urea, methylol-hydroxy-ethylene urea, dimethylol dihydroxy-ethylene urea, dimethylol-ethylene urea, dimethylol-propylene urea, dimethylol triazinone, dimethylol-glyoxal monoureine, tetramethylol-acetylene diurea, dimethyl-dihydroxyimidazolone and dimethylol-hexahydropyrimidinone which crosslink with the cellulose fibre; and (3) a condensation catalyst acting as acid donator selected from the group consisting of chlorides, nitrates, and sulfates of zinc, magnesium and ammonium, hydrochlorides of aliphatic and aromatic amines, alkali salts of aliphatic monocarboxylic acids containing a halogen atom, and halogenacetamides; and the material thus treated is then dried and then subjected to dry heat at 150° to 230°C.
2. A process as recited in claim 1, wherein the impregnation bath additionally contains an oxidation agent which is effective when heated and under acidic conditions.
3. A process as recited in claim 2, wherein the impregnation bath contains an oxidation agent selected from the group consisting of chlorates and nitrates of alkali metals, zinc and magnesium.
1. A continuous process for the simultaneous highgrade finishing and dyeing of piece-goods of cellulose fibres and mixtures thereof with linear polyester fibres, with leuco esters of vat dyestuffs wherein: the textile material is impregnated at room temperature with an aqueous bath which contains (1) a leuco ester of a vat dyestuff; (2) an aminoplastprecondensate which may be heat hardenable and/or a reactant resin selected from the group of cyclic urea derivatives consisting of methylol-ethylene urea, methylol-hydroxy-ethylene urea, dimethylol dihydroxy-ethylene urea, dimethylol-ethylene urea, dimethylol-propylene urea, dimethylol triazinone, dimethylol-glyoxal monoureine, tetramethylol-acetylene diurea, dimethyl-dihydroxyimidazolone and dimethylol-hexahydropyrimidinone which crosslink with the cellulose fibre; and (3) a condensation catalyst acting as acid donator selected from the group consisting of chlorides, nitrates, and sulfates of zinc, magnesium and ammonium, hydrochlorides of aliphatic and aromatic amines, alkali salts of aliphatic monocarboxylic acids containing a halogen atom, and halogenacetamides; and the material thus treated is then dried and then subjected to dry heat at 150° to 230°C.
2. A process as recited in claim 1, wherein the impregnation bath additionally contains an oxidation agent which is effective when heated and under acidic conditions.
3. A process as recited in claim 2, wherein the impregnation bath contains an oxidation agent selected from the group consisting of chlorates and nitrates of alkali metals, zinc and magnesium.
Description:
The present invention relates to a process for the simultaneous high-grade finishing and dyeing with leuco esters of vat dyestuffs, of cellulosic piece goods and mixtures thereof with synthetic fibres in a continuous working method.
From German Offenlegungsschrift No. 1,469,700 a process is known according to which leuco esters of vat dyestuffs can be dyed on mixed fabrics of linear polyester and cellulose fibres according to a thermosol process [cf. Melliand Textilberichte 38/10 (1957), pages 1,157 to 1,159]. The padding liquor prepared in a neutral medium contains chemical products, which split off acid in the heat, saponifying, thus, the dyestuff esters applied onto the fibre material. The oxidation to the dyestuff pigment takes place spontaneously by the atmospheric oxygen and may be improved by the oxydating agents which are simultaneously used. By using suitable auxiliaries and varying the thermal conditions it is possible according to this state of the art to obtain on both fibre portions the same color intensity (tone-in tone covering).
The pad-thermosol-process has not been adopted for the dyeing of piece goods of pure cellulose fibres with leuco esters of vat dyestuffs, since there has been no need of it on account of the perfect working of the two-bath development of paddings with these dyestuffs. However, if in this case, the dyeing process can be combined with a finishing process, the method of operation according to the thermosol process is not only possible, but also has technical and economical advantages:
It has now been found that piece goods of cellulose fibres or mixtures thereof with synthetic fibres, preferably polyester fibres, may be high-grade finished and simultaneously dyed with leuco esters of vat dyestuffs in a continuous working method, when the textile material is impregnated at room temperature with an aqueous bath which contains, besides leuco esters of vat dyestuffs, aminoplast precondensates which may be hardened in the heat and/or reactant resins which act to give cross-linking effects with the cellulose fibre, together with condensation catalysts acting simultaneously as acid donators, the material thus treated is dried and then subjected to the action of dry heat at 150° to 230° C.
When carrying out the process of the invention, the fact is considered that the acid- or hardening catalysts available in the dyebaths together with the leuco vat esters and resin formers, split off acid in the heat and that they act as catalysts for the condensation or fibre reaction of the high-grade finishing products as well as for the acidic saponification of the ester bond of the dyestuffs. The oxydation of the split leuco dyestuff to the dyestuff pigment takes place during the thermal treatment of the material spontaneously by the atmospheric oxygen only or it may be favored by oxydating agents which are also used.
The color yield and the fastnesses of the dyeings obtained according to the present invention (in the case of mixtures of cellulose with polyester fibres on both fibre portions) and the high-grade finishing effect with regard to the angle of crease recovery of fabrics thus-finished corresponds in all aspects to the results of a finish, in which dyeing and finishing are effected subsequently. The mixed fabrics treated according to the invention are dyed on both fibre portions in nearly the same shade and the same color intensity.
The leuco esters of vat dyestuffs used according to the process claimed are water-soluble dyestuffs prepared from vat dyestuffs by esterification, preferably with sulfuric acid, which may belong to the indigo, thiondigo type and the corresponding derivatives thereof, to the anthraquinone dyestuffs having one or several anthraquinone nuclei, to the indanthrone, flavanthrone and anthraquinone carbazole, to the acridones, (thio-)oxanthrones, pyranthrones, anthranthrones and anthrinides and of the dibenzanthrone and dibenzopyrenquinone type and other compounds.
As resin formers for the high-grade finish of the textile articles may be considered according to the new process, in the presence of a catalyst and at a higher temperature with selfcondensation, cross-linking aminoplast-precondensates of the type of the urea and melamine-formaldehyde resins, for example monomethylol-urea, dimethylol-urea, hexamethylolmelamine and the methyl ethers thereof or mixtures of these substances. From the class of reactant resins, which show mono- or bifunctional reactions with the cellulose-hydroxyl groups while cross-linking, there may be mentioned cyclic urea derivatives, especially methylol-ethylene urea, methylol-hydroxy-ethylene urea, dimethylol-dihydroxy-ethylene urea, dimethylol-ethylene urea, dimethylol-propylene urea, dimethylol-triazinone, dimethylol-glyoxal monoureine, tetramethylol-acetylene diurea (tetramethylol-glyoxal diureine), and dimethyldihydroxy-imidazolone, furthermore dimethylol-adipic acid diamide, dimethylol-butanediol-diurethane, dimethylol-hexahydropyrimidinone, polycarbonates as well as acrylamides. These resin-treating agents are used in the amounts usual for the high-grade finishing of textiles of about 1 to 25 percent by weight, preferably 2 to 15 percent by weight, calculated on the textile material to be finished.
For the acidic saponification of the leuco ester of the vat dyestuff are used according to the invention those inorganic or organic compounds, which split off acid in the heat by reaction or hydrolysis, such as the chlorides, nitrates or sulfates of zinc, magnesium or ammonium, the hydrochlorides of aliphatic or aromatic amines, the alkali salts of aliphatic monocarboxylic acids with a halogen atom or halogenacetamides.
To favor the development of the leuco esters of vat dyestuffs and, thus, to improve the dyestuff yield, the dyebaths used may contain those oxydating agents, which develop their oxydating action only in the heat and in the acidic medium formed, for example chlorates or nitrates of alkali metals, zinc or magnesium, preferably sodium chlorate.
The process of the invention for the simultaneous fixation of high-grade finishing products and leuco esters of vat dyestuffs on textiles may be applied to the known cellulosic fibres and mixtures of synthetic fibres and cellulose fibres.
The cellulose fibres may be native fibres, such as flax, hemp, linen, cotton, or regenerated fibres, such as viscose, spun rayon, modal fibres (polynosic type).
The synthetic fibres in these mixtures are preferably those of known linear polyesters.
The principle of the working of the new process for being applied to cellulose fibres and to polyester/cellulose mixtures is describes below:
1. Padding liquor
a. The leuco ester of the vat dyestuff is dissolved hot in water without the addition of alkalis. In case wetting or padding auxiliaries are also used, these ones are dissolved together with the dyestuff. This solution is cooled or diluted with cold water.
b. The precondensate of the synthetic resins or reactant products which are generally available as a 50 % aqueous solution, are diluted in the amount forseen with cold water to about the double volume.
c. The acid-donators (hardening or reactant catalysts) are dissolved in cold water. In case oxydating agents (for example sodium chlorate) and an oxygen carrier (for example ammonium vanadate) are also used, these substances are added to the acid donator solutions. The solutions obtained in this way have a slightly acidic reaction, a neutralization with diluted sodium carbonate solution or ammonia to reach a pH value of 6 to 7 is possible, but not obligatory.
The solutions (a), (b) and (c) obtained in the manner above-described are combined with one another and filled up to the final volume with cold or luke warm water. The final temperature of the dyebath shall amount to 20° ° 30°C.
It has been surprising that the leuco esters of vat dyestuffs remain stable up to 30 hours in these baths despite the low pH value, even without previous neutralization, without being previously split, causing, thus, a loss of yield.
2. Padding and drying
The material is padded on a foulard at a liquor pick-up of 50 - 70 percent by weight with the bath prepared in this manner, and after a short passage through the air, during which the bath may enter into the interior of the threads and fibres, the material is dried at temperatures of from 90° to 120°C on suitable apparatus, as for example hot flues, tenters, infrared devices or the like.
The dyebath may be applied according to the present process not only by padding but also by slop-padding, dipping or spraying.
3. Thermal treatment (thermosolation, condensation, fibre reaction)
The dried fabric is subjected to a thermal treatment, either under conditions of temperature and reaction time most suitable for the condensation or fibre reaction of the finishing agents chosen, or, above all in the case of polyester mixtures, under thermosol conditions, preferably by means of hot air, during 1 to 180 seconds at temperatures of from 150° to 230°C, preferably for 10 to 120 seconds between 150° and 210°C.
The leuco ester of the vat dyestuff is fixed on the fibre or on both fibre portions, acidically saponified (split), reoxydized and the pre-condensates are condensed to a resin or cross-linked with the cellulose fibre.
4. After-treatment
The material is rinsed and soaped in a soda-alkaline medium at boiling temperature and in the presence of sequestration agents.
With regard to the practicability of the process claimed it has been surprising that the acidic high-grade finishing catalysts can simultaneously exert the function of the acidic saponification of the dyestuff ester and that a considerable amount of the dyestuff is fixed in the fibre and only a small portion is fixed in the resin layer. The distrubution of the dyestuff in the system fibre/layer depends to a small extent on the thermal conditions.
The following Examples illustrate the invention. The Colour Index Numbers indicated in the Examples for characterizing the dyestuffs were taken from the second edition 1956 as well as from the supplementary volume 1963.
EXAMPLE 1
A cotton fabric was padded on a foulard at a weight increase (liquor pick-up) of about 60 % with a bath of room temperature, which was prepared as follows:
a. 6 g of the leuco ester vat dyestuff Solubilized Vat Orange 1 - C.I.-No. 59 106 were dissolved in 50 ml of hot water, mixed with 1 g of diethylnaphthalene sulfonate and allowed to cool at room temperature.
b. 120 g of a 50 % aqueous solution of dimethylol-dihydroxyethylene urea were diluted with 200 ml of cold water.
c. 10 g of zinc nitrate-hexahydrate, Zn(NO 3 ) 2 . 6 H 2 O and 2 g of sodium chlorate were dissolved in 100 ml of cold water and mixed with 2 ml of a 1 % ammonium vanadate solution.
The three solutions were combined, completed by addition of cold water to a bath volume of 1 liter.
The material thus padded was dried at 100°C and then subjected for 30 seconds to a dry heat treatment at 180°C. Finally the dyeing was rinsed with water, soaped in usual manner with alkaline baths at boiling temperature and worked up.
A fast yellow dyeing with a good color yield and a good angle of crease recovery of the material was obtained.
EXAMPLE 2
A bath was prepared as follows:
a. 6 g of the leuco ester vat dyestuff Solubilised Vat Blue 6 - C.I.-No. 69 826 and 1 g of diethylnaphthalene sulfonate were dissolved in 50 ml of hot water and this solution was cooled by addition of 150 ml of cold water.
b. 150 g of a 50 % aqueous solution of a methylol-ureaprecondensate were diluted with 150 ml of cold water. c. 15 g of magnesium chloride-hexahydrate, MgCl 2 .6 H 2 O were dissolved in 100 ml of cold water.
The solutions (a), (b) and (c) were combined with one another in the order indicated and completed with luke warm water to a volume of 1 liter; the final temperature of the dyebath was to be about 25°C.
A piece-good of viscose cellulose was padded on a foulard with this bath, at a weight increase (liquor pick-up) of 70 %, the textile good was dried at 100°C and treated for 3 minutes with dry heat at 150°C.
A fast blue dyeing with a good angle of crease recovery of the fabric was obtained.
EXAMPLE 3
A dyeing liquor was prepared as follows:
a. 3 g of the leuco ester vat dyestuff Solubilised Vat Black 1 - C.I.-No. 73 671, 2 g of a reaction product of 1 mol of nonyl phenol and 8.5 mols of ethylene oxide and 1 g of diethylnaphthalene sulfonate were dissolved in 50 ml of hot water and cooled.
b. 100 g of a 50 % aqueous solution of dimethylolethylene urea were diluted with 200 ml of cold water.
c. 15 g of zinc chloride and 2 g of sodium chlorate were dissolved in 50 ml of cold water.
These three solutions were combined and the bath was adjusted with cold water to a final volume of 1 liter.
Piece-goods having a mixture of linear polyester fibres and cotton in the ratio of 67::33 were padded with this cold bath (or at temperatures of up to 30°C), at a weight increase of 50 % (liquor pick-up), the padded material was dried and treated for thermosolation for 30 seconds at 210°C.
A fast blue grey dyeing with a good angle of crease recovery of the fabric was obtained.
EXAMPLE 4
A dyebath was prepared as follows:
a. 4 g of the leuco ester vat dyestuff Solubilised Vat Red 1 - C.I.-No. 73 361, were dissolved in 50 ml of hot water and allowed to cool, if desired, while adding cold water.
b. 150 g of a 50 % aqueous solution of a pre-condensate of hexamethylolmelamine-hexamethyl ether
c. 10 g of zinc nitrate-hexahydrate, Zn(NO 3 ) 2 . 6 H 2 O and 2 g of sodium chlorate were dissolved in 50 ml of cold water.
The three solutions were combined and completed to 1 liter by addition of water; the bath temperature was to be about 30°C.
A well absorbent cotton piece-good was padded with this bath at a weight increase (liquor pick-up) of 70 %, the textile good was dried at 100°C and this material was treated for 30 seconds with dry heat at 180°C.
A fast pink dyeing with a good color yield and a good angle of crease recovery of the fabric was obtained.
EXAMPLE 5
A dyeing bath was prepared as follows:
a. 6 g of the leuco ester vat dyestuff Solubilised Vat Green 1 - C.I.-No. 59 826 and 2 g of a reaction product of one mol of nonyl phenol and 8.5 mols of ethylene oxide were dissolved in 50 ml of hot water and cooled to about room temperature with 200 ml of cold water
b. 100 g of an aqueous 50 % solution of N-methylolacrylamide and 100 g of an aqueous 50 % solution of dimethylolethylene urea were diluted with 200 ml. of cold water.
c. 10 g of zinc nitrate-hexahydrate, Zn(NO 3 ) 2 . 6 H 2 O and 2 g of a 1 % ammonium vanadate solution were dissolved in 50 ml of cold water.
The three solutions were combined and the bath was completed to 1 liter with water (final temperature of 25°-30°C).
Piece-goods of a mixture (67:33) of linear polyester fibres and cotton were padded with this bath at a weight increase of 50 % (liquor pick-up), the padded material was dried at 100°C and treated for 30 seconds under thermosol conditions at 210°C. The dyeing was after-treated by rinsing and boiling alkaline soaping.
A fast green dyeing with a good color yield and a good angle of crease-recovery of the fabric was obtained.
From German Offenlegungsschrift No. 1,469,700 a process is known according to which leuco esters of vat dyestuffs can be dyed on mixed fabrics of linear polyester and cellulose fibres according to a thermosol process [cf. Melliand Textilberichte 38/10 (1957), pages 1,157 to 1,159]. The padding liquor prepared in a neutral medium contains chemical products, which split off acid in the heat, saponifying, thus, the dyestuff esters applied onto the fibre material. The oxidation to the dyestuff pigment takes place spontaneously by the atmospheric oxygen and may be improved by the oxydating agents which are simultaneously used. By using suitable auxiliaries and varying the thermal conditions it is possible according to this state of the art to obtain on both fibre portions the same color intensity (tone-in tone covering).
The pad-thermosol-process has not been adopted for the dyeing of piece goods of pure cellulose fibres with leuco esters of vat dyestuffs, since there has been no need of it on account of the perfect working of the two-bath development of paddings with these dyestuffs. However, if in this case, the dyeing process can be combined with a finishing process, the method of operation according to the thermosol process is not only possible, but also has technical and economical advantages:
It has now been found that piece goods of cellulose fibres or mixtures thereof with synthetic fibres, preferably polyester fibres, may be high-grade finished and simultaneously dyed with leuco esters of vat dyestuffs in a continuous working method, when the textile material is impregnated at room temperature with an aqueous bath which contains, besides leuco esters of vat dyestuffs, aminoplast precondensates which may be hardened in the heat and/or reactant resins which act to give cross-linking effects with the cellulose fibre, together with condensation catalysts acting simultaneously as acid donators, the material thus treated is dried and then subjected to the action of dry heat at 150° to 230° C.
When carrying out the process of the invention, the fact is considered that the acid- or hardening catalysts available in the dyebaths together with the leuco vat esters and resin formers, split off acid in the heat and that they act as catalysts for the condensation or fibre reaction of the high-grade finishing products as well as for the acidic saponification of the ester bond of the dyestuffs. The oxydation of the split leuco dyestuff to the dyestuff pigment takes place during the thermal treatment of the material spontaneously by the atmospheric oxygen only or it may be favored by oxydating agents which are also used.
The color yield and the fastnesses of the dyeings obtained according to the present invention (in the case of mixtures of cellulose with polyester fibres on both fibre portions) and the high-grade finishing effect with regard to the angle of crease recovery of fabrics thus-finished corresponds in all aspects to the results of a finish, in which dyeing and finishing are effected subsequently. The mixed fabrics treated according to the invention are dyed on both fibre portions in nearly the same shade and the same color intensity.
The leuco esters of vat dyestuffs used according to the process claimed are water-soluble dyestuffs prepared from vat dyestuffs by esterification, preferably with sulfuric acid, which may belong to the indigo, thiondigo type and the corresponding derivatives thereof, to the anthraquinone dyestuffs having one or several anthraquinone nuclei, to the indanthrone, flavanthrone and anthraquinone carbazole, to the acridones, (thio-)oxanthrones, pyranthrones, anthranthrones and anthrinides and of the dibenzanthrone and dibenzopyrenquinone type and other compounds.
As resin formers for the high-grade finish of the textile articles may be considered according to the new process, in the presence of a catalyst and at a higher temperature with selfcondensation, cross-linking aminoplast-precondensates of the type of the urea and melamine-formaldehyde resins, for example monomethylol-urea, dimethylol-urea, hexamethylolmelamine and the methyl ethers thereof or mixtures of these substances. From the class of reactant resins, which show mono- or bifunctional reactions with the cellulose-hydroxyl groups while cross-linking, there may be mentioned cyclic urea derivatives, especially methylol-ethylene urea, methylol-hydroxy-ethylene urea, dimethylol-dihydroxy-ethylene urea, dimethylol-ethylene urea, dimethylol-propylene urea, dimethylol-triazinone, dimethylol-glyoxal monoureine, tetramethylol-acetylene diurea (tetramethylol-glyoxal diureine), and dimethyldihydroxy-imidazolone, furthermore dimethylol-adipic acid diamide, dimethylol-butanediol-diurethane, dimethylol-hexahydropyrimidinone, polycarbonates as well as acrylamides. These resin-treating agents are used in the amounts usual for the high-grade finishing of textiles of about 1 to 25 percent by weight, preferably 2 to 15 percent by weight, calculated on the textile material to be finished.
For the acidic saponification of the leuco ester of the vat dyestuff are used according to the invention those inorganic or organic compounds, which split off acid in the heat by reaction or hydrolysis, such as the chlorides, nitrates or sulfates of zinc, magnesium or ammonium, the hydrochlorides of aliphatic or aromatic amines, the alkali salts of aliphatic monocarboxylic acids with a halogen atom or halogenacetamides.
To favor the development of the leuco esters of vat dyestuffs and, thus, to improve the dyestuff yield, the dyebaths used may contain those oxydating agents, which develop their oxydating action only in the heat and in the acidic medium formed, for example chlorates or nitrates of alkali metals, zinc or magnesium, preferably sodium chlorate.
The process of the invention for the simultaneous fixation of high-grade finishing products and leuco esters of vat dyestuffs on textiles may be applied to the known cellulosic fibres and mixtures of synthetic fibres and cellulose fibres.
The cellulose fibres may be native fibres, such as flax, hemp, linen, cotton, or regenerated fibres, such as viscose, spun rayon, modal fibres (polynosic type).
The synthetic fibres in these mixtures are preferably those of known linear polyesters.
The principle of the working of the new process for being applied to cellulose fibres and to polyester/cellulose mixtures is describes below:
1. Padding liquor
a. The leuco ester of the vat dyestuff is dissolved hot in water without the addition of alkalis. In case wetting or padding auxiliaries are also used, these ones are dissolved together with the dyestuff. This solution is cooled or diluted with cold water.
b. The precondensate of the synthetic resins or reactant products which are generally available as a 50 % aqueous solution, are diluted in the amount forseen with cold water to about the double volume.
c. The acid-donators (hardening or reactant catalysts) are dissolved in cold water. In case oxydating agents (for example sodium chlorate) and an oxygen carrier (for example ammonium vanadate) are also used, these substances are added to the acid donator solutions. The solutions obtained in this way have a slightly acidic reaction, a neutralization with diluted sodium carbonate solution or ammonia to reach a pH value of 6 to 7 is possible, but not obligatory.
The solutions (a), (b) and (c) obtained in the manner above-described are combined with one another and filled up to the final volume with cold or luke warm water. The final temperature of the dyebath shall amount to 20° ° 30°C.
It has been surprising that the leuco esters of vat dyestuffs remain stable up to 30 hours in these baths despite the low pH value, even without previous neutralization, without being previously split, causing, thus, a loss of yield.
2. Padding and drying
The material is padded on a foulard at a liquor pick-up of 50 - 70 percent by weight with the bath prepared in this manner, and after a short passage through the air, during which the bath may enter into the interior of the threads and fibres, the material is dried at temperatures of from 90° to 120°C on suitable apparatus, as for example hot flues, tenters, infrared devices or the like.
The dyebath may be applied according to the present process not only by padding but also by slop-padding, dipping or spraying.
3. Thermal treatment (thermosolation, condensation, fibre reaction)
The dried fabric is subjected to a thermal treatment, either under conditions of temperature and reaction time most suitable for the condensation or fibre reaction of the finishing agents chosen, or, above all in the case of polyester mixtures, under thermosol conditions, preferably by means of hot air, during 1 to 180 seconds at temperatures of from 150° to 230°C, preferably for 10 to 120 seconds between 150° and 210°C.
The leuco ester of the vat dyestuff is fixed on the fibre or on both fibre portions, acidically saponified (split), reoxydized and the pre-condensates are condensed to a resin or cross-linked with the cellulose fibre.
4. After-treatment
The material is rinsed and soaped in a soda-alkaline medium at boiling temperature and in the presence of sequestration agents.
With regard to the practicability of the process claimed it has been surprising that the acidic high-grade finishing catalysts can simultaneously exert the function of the acidic saponification of the dyestuff ester and that a considerable amount of the dyestuff is fixed in the fibre and only a small portion is fixed in the resin layer. The distrubution of the dyestuff in the system fibre/layer depends to a small extent on the thermal conditions.
The following Examples illustrate the invention. The Colour Index Numbers indicated in the Examples for characterizing the dyestuffs were taken from the second edition 1956 as well as from the supplementary volume 1963.
EXAMPLE 1
A cotton fabric was padded on a foulard at a weight increase (liquor pick-up) of about 60 % with a bath of room temperature, which was prepared as follows:
a. 6 g of the leuco ester vat dyestuff Solubilized Vat Orange 1 - C.I.-No. 59 106 were dissolved in 50 ml of hot water, mixed with 1 g of diethylnaphthalene sulfonate and allowed to cool at room temperature.
b. 120 g of a 50 % aqueous solution of dimethylol-dihydroxyethylene urea were diluted with 200 ml of cold water.
c. 10 g of zinc nitrate-hexahydrate, Zn(NO 3 ) 2 . 6 H 2 O and 2 g of sodium chlorate were dissolved in 100 ml of cold water and mixed with 2 ml of a 1 % ammonium vanadate solution.
The three solutions were combined, completed by addition of cold water to a bath volume of 1 liter.
The material thus padded was dried at 100°C and then subjected for 30 seconds to a dry heat treatment at 180°C. Finally the dyeing was rinsed with water, soaped in usual manner with alkaline baths at boiling temperature and worked up.
A fast yellow dyeing with a good color yield and a good angle of crease recovery of the material was obtained.
EXAMPLE 2
A bath was prepared as follows:
a. 6 g of the leuco ester vat dyestuff Solubilised Vat Blue 6 - C.I.-No. 69 826 and 1 g of diethylnaphthalene sulfonate were dissolved in 50 ml of hot water and this solution was cooled by addition of 150 ml of cold water.
b. 150 g of a 50 % aqueous solution of a methylol-ureaprecondensate were diluted with 150 ml of cold water. c. 15 g of magnesium chloride-hexahydrate, MgCl 2 .6 H 2 O were dissolved in 100 ml of cold water.
The solutions (a), (b) and (c) were combined with one another in the order indicated and completed with luke warm water to a volume of 1 liter; the final temperature of the dyebath was to be about 25°C.
A piece-good of viscose cellulose was padded on a foulard with this bath, at a weight increase (liquor pick-up) of 70 %, the textile good was dried at 100°C and treated for 3 minutes with dry heat at 150°C.
A fast blue dyeing with a good angle of crease recovery of the fabric was obtained.
EXAMPLE 3
A dyeing liquor was prepared as follows:
a. 3 g of the leuco ester vat dyestuff Solubilised Vat Black 1 - C.I.-No. 73 671, 2 g of a reaction product of 1 mol of nonyl phenol and 8.5 mols of ethylene oxide and 1 g of diethylnaphthalene sulfonate were dissolved in 50 ml of hot water and cooled.
b. 100 g of a 50 % aqueous solution of dimethylolethylene urea were diluted with 200 ml of cold water.
c. 15 g of zinc chloride and 2 g of sodium chlorate were dissolved in 50 ml of cold water.
These three solutions were combined and the bath was adjusted with cold water to a final volume of 1 liter.
Piece-goods having a mixture of linear polyester fibres and cotton in the ratio of 67::33 were padded with this cold bath (or at temperatures of up to 30°C), at a weight increase of 50 % (liquor pick-up), the padded material was dried and treated for thermosolation for 30 seconds at 210°C.
A fast blue grey dyeing with a good angle of crease recovery of the fabric was obtained.
EXAMPLE 4
A dyebath was prepared as follows:
a. 4 g of the leuco ester vat dyestuff Solubilised Vat Red 1 - C.I.-No. 73 361, were dissolved in 50 ml of hot water and allowed to cool, if desired, while adding cold water.
b. 150 g of a 50 % aqueous solution of a pre-condensate of hexamethylolmelamine-hexamethyl ether
c. 10 g of zinc nitrate-hexahydrate, Zn(NO 3 ) 2 . 6 H 2 O and 2 g of sodium chlorate were dissolved in 50 ml of cold water.
The three solutions were combined and completed to 1 liter by addition of water; the bath temperature was to be about 30°C.
A well absorbent cotton piece-good was padded with this bath at a weight increase (liquor pick-up) of 70 %, the textile good was dried at 100°C and this material was treated for 30 seconds with dry heat at 180°C.
A fast pink dyeing with a good color yield and a good angle of crease recovery of the fabric was obtained.
EXAMPLE 5
A dyeing bath was prepared as follows:
a. 6 g of the leuco ester vat dyestuff Solubilised Vat Green 1 - C.I.-No. 59 826 and 2 g of a reaction product of one mol of nonyl phenol and 8.5 mols of ethylene oxide were dissolved in 50 ml of hot water and cooled to about room temperature with 200 ml of cold water
b. 100 g of an aqueous 50 % solution of N-methylolacrylamide and 100 g of an aqueous 50 % solution of dimethylolethylene urea were diluted with 200 ml. of cold water.
c. 10 g of zinc nitrate-hexahydrate, Zn(NO 3 ) 2 . 6 H 2 O and 2 g of a 1 % ammonium vanadate solution were dissolved in 50 ml of cold water.
The three solutions were combined and the bath was completed to 1 liter with water (final temperature of 25°-30°C).
Piece-goods of a mixture (67:33) of linear polyester fibres and cotton were padded with this bath at a weight increase of 50 % (liquor pick-up), the padded material was dried at 100°C and treated for 30 seconds under thermosol conditions at 210°C. The dyeing was after-treated by rinsing and boiling alkaline soaping.
A fast green dyeing with a good color yield and a good angle of crease-recovery of the fabric was obtained.