US2993743A

US2993743A - i i ttts

Info

Publication number: US2993743A
Authority: US
Publication date: 1961-07-25
Anticipated expiration: 1978-07-25

Description

tates This invention relates to an indirect process of printing with vat and sulfur dyestuffs in which a solution of an alkali salt of straight-chain or branched hydroxyalkyl sulfinic acid with 2 to 4 carbon atoms is used as reducing agent.

Processes for the printing of textile goods with vat and sulfur dyestulfs are known in which the dyestuff is printed on together with certain coagulable thickening agents, for example with alkyl cellulose ethers, carob bean flour ether, polyvinyl alcohol, ethers of gum guar, alginates or also simple carob bean flour thickening. The printing pastes themselves contain no reducing agent, but now and again alkaline agents, such as potassium or sodium carbonate or also sodium hydroxide depending on the compatibility of the thickenings with these alkaline agents. After printing and drying, the goods are treated with solutions of reducing agents, possibly containing alkaline agents, which usually contain additions which effect or promote the coagulation of the above-mentioned thickening agents, such as sodium borate or sodium aluminate, and in many cases also sodium sulfate. These reducing agents are sometimes thickened with non-coagulable thickening agents.

Immediately after preparation, for example by means of a foulard or engraved rollers, the textiles, while thus still in a moist state, and supplied to a heat treatment with exclusion of air. The reduction and fixation of the dyestulfs are thereby achieved. The heat-transferring agent may be air-free saturated or superheated steam of 1 to 3 atmospheres absolute, at a temperature of 100 to 200 C. Hot metal baths or hot oil baths may however also be used, and also hot Water which may if desired be enriched with agents having an electrolytic action. The heat may also be transmitted to the moist textile goods by hot metallic surfaces, the access of atmospheric oxygen to the textile goods being prevented by a preheated rubber cloth.

In all these methods, which are known under the terms two-phase printing methods or indirect printing with vat dyestuffs or vat-pigment printing methods, there is preferably used as reducing agent sodium formaldehyde sulfoxylate. and more rarely sodium dithionite. These printing methods are hereinafter defined as two-phase printing method or two-phase printing process.

The advantage of sodium formaldehyde sulfoxylate solutions lies in the stability of these solutions at 20 C. and also in the fact that these solutions still do not have a reducing action on vat dyestuffs at 20 C. Thus when padding the printed fabric web in the foulard chassis there does not occur either a vatting of the printed dyestuft (and consequently a bleeding out onto the unprinted places) or a staining or tinting of the padding liquor. When it is desired to achieve with the development of the printed dyestuif a simultaneous coloring of the unprinted places in pale shades, there may be added to the sodium formaldehyde sulfoxylate solution a small amount of a vat and/ or sulfur dyestulf.

It is however disadvantageous that when using sodium formaldehyde sulfoxylate as reducing agent in the usual steamers, treatment times of 3 to 5 minutes per square meter weight of the textile web are required in atent order completely to fix the dyestufi printed on. If sodium dithionite is used as reducing agent, it is true that shorter steaming times of about 30 seconds duration are possible, but it is a disadvantage that sodium dithionite solutions reduce vat dyestuffs already at 20 C. in the presence of alkali hydroxides and/or alkali carbonates. This gives rise to the following consequences; the printed vat dyestuffs vat in the preparation in the foulard chassis, bleed into the nonprinted ground and also tint or stain the padding liquor or the thickened sodium dithionite solution in an undesirable way.

The instability of cold sodium dithionite solutions, also in the presence of alkaline agents, is also disadvantageous. Thus when using sodium dithionite fixation it is necessary to prepare the padding liquor for the treatment of the fabric fresh at short intervals, i.e. at intervals of 30 to minutes.

With this state of the art, methods were sought after which would combine the advantages of reduction with sodium dithionite and the advantages of reduction with sodium formaldehyde sulfoxylate without exhibiting the disadvantages which the use of these reducing agents occasions.

We have found that textile goods can be printed with dyestuffs selected from the group consisting of vat dyestuffs and sulfur dyestufis by:

(1) Printing the goods in the first stage with dyestuffs with the addition of coagulable thickening agents and, after drying, fixing the prints in a second stage by treatment with a solution of an alkali salt of a straightchain or branched hydroxy-alkyl sulfinic acid with 2 to 4 carbon atoms which contains an alkaline agent and subsequent short heat treatment,

(2) Printing the goods in the first stage with dyestuffs with the addition of alkaline agents and coagulable thickening agents and, after drying, fixing the prints in a second stage by treatment with a solution of an alkali salt of a straight-chain or branched hydroxy-alkyl sulfinic acid with 2 to 4 carbon atoms and subsequent short heat treatment,

(3) Printing the goods in the first stage with dyestuff-s with the addition of non-co-agulable thickening agents and, after drying, fixing the prints in a second stage by spraying on a solution, containing an alkaline agent, of an alkali salt of a hydroxy-alkyl sulfinic acid with 2 to 4 carbon atoms and subsequent short heat treatment, or

(4) Printing the goods in the first stage with dyestuffs with the addition of alkaline agents and non-coagulable thickening agents and fixing the prints in a second stage by spraying on a solution of an alkali salt of a hydroxy-alkyl sulfinic acid with 2 to 4 carbon atoms and subsequent short heat treatment.

Included in the term textile goods are to be understood structures, such as woven or knitted fabrics, especially those of native and/or regenerated cellulose, natural silk or linear polyamides. As alkali salts of hydroxy-alkyl sulfinic acids with 2 to 4 carbon atoms there may be mentioned for example the sodium, potassium or ammonium salts of hydroxy-ethane sulfinic acid, hydroxy-normal-propane sulfinic acid, hydroxy-iso-propane sulfinic acid or hydroxy-normal-butane sulfinicacid, and as alkaline agents there may be mentioned for example sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate and/or mixtures of the same. As coagulable thickening agents there may be mentioned for example alkyl cellulose ethers, carob bean flour ether, polyvinyl alcohol, ethers of gum guar, alginates or also simple carob bean flour thickenings and, as non-coagulable thickening agents there may be mentioned for example tragacanth mucilage. The fixation of the prints is effected by a short heat treatment of 10 to 60 seconds duration at a temperature of 80 to 200 C., advantageously between 90 and 120 C.

The preparation of the sulfinic acid compounds employed in the process of the invention can be accomplished by well known methods, e.g. by reaction of the corresponding aldehydes or ketones with metal hyposulfites, preferably sodium or zinc hyposulfites. The resulting products are the metal salts of hydroxy-alkyl sulfinic acids with 2 to 4 carbon atoms. See, for example, the preparation of sulfinic acids as disclosed by Gilman, Organic Chemistry, vol. I, pp. 9l3-9l9, 2nd ed., John Wiley & Sons, Inc., New York (1949).

Solutions of alkali salts of hydroxy-alkyl sulfinic acids with '2 to 4 carbon atoms can be obtained for example by dissolving the corresponding salts in water. Such solutions may however also be obtained from the salts of hydroxy-alkyl sulfinic acids with 2 to 4 carbon atoms which are difiicultly soluble in water, for example the calcium, barium, di-zinc or mono-zinc salts, by treatment with aqueous solutions of alkali hydroxides or carbonates, for example sodium or potassium hydroxide or carbonate, by so-called double decomposition.

An advantage of the new process consists in the fact that the alkali salts of straight-chain or branched hydroxy-alkyl sulfinic acids with 2 to 4 carbon atoms used as reducing agents, and which do not reduce dyestuffs at room temperature even in the presence of strongly alkaline agents, such as sodium or potassium hydroxide, and therefore do not cause any detachment of dyestuff in the padding liquor during the preparation of the printed fabric, have such a high decomposition speed at temperatures above 50 C. that the dyestuffs can be fixed on the fiber with a heat treatment which is just as short as when using sodium dithionite as reducing agent. The new rapid fixing process moreover permits the use of a far greater number of vat dyestuffs than hitherto, because when using sodium dithionite only those vat dyestuffs could be used which by reason of their high leuco dyestuif potential were not reduced by cold hyposulfite solutions. The stability of aqueous solutions of the alkali salts of straight-chain or branched hydroxy-alkyl sulfinic acids with 2 to 4 carbon atoms is so great even at 20 C. against the oxygen and carbon dioxide content of the air that aqueous solutions can be sprayed onto the printed textile goods without suffering appreciable loss of reducing agent. On the contrary if aqueous sodium dithionite solutions are sprayed, usually only between and 30% of the reducing agent originally present can be detected in the solution collected after spraying. It is true that aqueous solutions of sodium formaldehyde sulfoxylate can be sprayed without appreciable diminution in reducing value but it is known that the use of this reducing agent necessitates a much longer heat treatment of the textile goods for the fixation of the dyestuffs. On the contrary if the printed fabric is sprayed, as above described, with aqueous solutions of alkali salts of straightchain or branched hydroxy-alkyl sufinic acids with 2 to 4 carbon atoms it is possible on the one hand to use short heat treatment periods and on the other hand it is no longer essential to use coagulable thickenings in the printing pastes.

The following examples will further illustrate this invention but the invention is not restricted to these examples. The parts and percentages specified are parts and percentages by weight.

Example 1 A cotton fabric is printed with the following printing paste:

100 parts of a yellow vat dyestuif, for example Vat Yellow 1, 0.1. 70600 (Color Index, 1956, volume 2, page 2427) in the form of a 20% aqueous paste;

100 parts of water;

600 parts of a 3% decoction of carob bean flour; and

- 4 200 parts of a 10% wheat starch paste (making 1000 parts in all).

After printing and drying, the fabric is prepared with:

800 parts of water;

200 parts of a 30% aqueous solution of the potassium salt, of hydroxy-ethane sulfinic acid;

50 parts of sodium hydroxide; and

5 parts of sodium tetraborate.

The fabric, while still moist, is then exposed for 30 seconds to an air-free steam atmosphere without excess pressure at 108 C. To finish off" the print, the fabric is treated for 2 minutes in flowing water at 20 C., oxidized for 2 minutes in an aqueous solution at C. which contains 2 grams of sodium perborate per liter, soaped, rinsed and dried. A brilliant yellow print on a white ground is obtained.

The same result is achieved when the prepared still moist fabric, instead of being subjected to the 30 seconds steaming process, is applied to a metallic surface heated to'l10 C. and covered with a rubber cloth preheated to about 80 'C., the said heat treatment lasting for 25 seconds.

Example 2 A viscose rayon staple fiber fabric is printed with the following printing paste:

parts of a blue vat dyestuif, for example Vat Blue 14, CI. 69810 (Color Index, 1956, volume 2, page 2501) in the form of a 15% aqueous paste;

50 parts of water;

600 parts of a 4.5% carob bean flour decoction in water;

200 parts of a 10% maize starch paste;

30 parts of potassium carbonate; and

20 parts of sodium hydroxide (making 1000 parts in all).

After printing and drying, it is treated with a solution of:

850 parts of water;

150 parts of a 40% aqueous solution of the potassium salt of hydroxypropane sulfinic acid; and

15 parts of sodium tetraborate.

Example 3 A cotton fabric is printed with the following printing paste:

100 parts of a yellow vat dyestuff, for example Vat Yellow 1, CI. 70600 (Color Index, 1956, volume 2, page 2427) in the form of a 20% aqueous paste;

150 parts of water;

500 parts of 6% tragacanth mucilage; and

250 parts of a 10% wheat starch paste (making 1000 parts in all).

The printed and dried fabric is sprayed with the following solution so that the fabric absorbs at least 50% of its own weight of solution:

800 parts of Water;

200 parts of a 40% aqueous solution of the sodium salt of hydroxy-ethane sulfinic acid; and

50 parts of sodium hydroxide.

The still moist fabric is continuously supplied to a steamer and there treated for 30 seconds at about C. in air-free steam without excess pressure. The fabric is finished off according to Example 1.

A brilliant yellow print is obtained on a white ground.

Instead of the solution of the sodium salt of hydroxyethane sulfinic acid, there may also be used a solution of the ammonium salt of hydroxy-ethane sulfinic acid under otherwise identical conditions.

Example 4 A cuprammonium rayon fabric is printed with the following paste:

800 parts of water;

200 parts of a 35% aqueous solution of the sodium salt of hydroxy-butane sulfinic acid; and

50 parts of sodium hydroxide.

The still moist fabric is continuously supplied to a steamer and treated therein for 30 seconds at 110 C. with air-free steam. The finishing off of the fabric takes place in the same way as described in Example 1.

The result is a brilliant red-violet print on a white ground.

Instead of the sodium salt of hydroxy-butane sulfinic acid there may also be used the sodium, potassium or ammonium salts of hydroxy-iso-propane sulfinic acid or their aqueous solutions.

Example 5 A natural silk fabric is printed according to the following prescription:

40 parts of a green vat dyestufi, for example Vat Green 1, CI. 59855 (Color Index, 1956, volume 2, page 2519) in the form of a aqueous paste;

210 parts of water;

500 parts of a 5% alkyl cellulose ether thickening; and

250 par-ts of a 10% wheat starch thickening (making 1000 parts in all).

After printing and drying, it is padded on the foulard with the following solution:

850 parts of water;

150 parts of a 30% aqueous solution of the sodium salt of hydroxy-ethane sulfinic acid;

parts of sodium hydroxide; and

25 parts of potassium carbonate.

The still moist material is treated for 60 seconds at 0.3 atmosphere excess pressure with air free steam. The further finishing oif takes place according to Example 1.

The product is a brilliant green print on a white ground.

The alkyl cellulose ether thickening may also be replaced by the same amount of a 17% polyvinyl alcohol thickening.

Example 6 A fabric of polycaprolactam fibrous material is printed with the following paste:

40 parts of a green vat dyestuff, for example Vat Green 1, CI. 59855 (Color Index, 195 6, volume 2, page 2519) in the form of a 10% aqueous paste;

110 parts of water;

600 parts of a 5% sodium alginate thickening; and

250 parts of a 10% wheat starch paste.

After printing and drying, it is padded with the following solution on a two-roller foulard:

800 parts of water;

15 parts of aluminum sulfate (anhydrous);

45 parts of sodium hydroxide;

40 parts of sodium carbonate (calcined); and

200 parts of a 40% aqueous solution of the potassium salt of hydroxy-ethane sulfinic acid.

The moist fabric is supplied continuously to a steamer and treated therein for 50 seconds with air-free steam at 105 C. The steamed print is finished off according to Example 1 and a full bluish-green print is obtained on a white ground.

Steaming may also be for 40 seconds at an excess pressure of 1.5 atmospheres.

Example 7 A cotton fabric is printed with the following printing paste:

20 parts of a grey vat dyestuif, for example Vat Black 25, Cl. 69525 (Color Index, 1956, volume 2, page 2560) in the form of a 20% aqueous paste;

130 parts of water;

600 parts of a 4.5% gum guar ether decoction in water;

and

250 parts of a 10% wheat starch paste (making 1000 parts in all).

After printing and drying it is padded on the tworoller foulard with the following solution:

850 parts of water;

150 parts of a 30% aqueous solution of the potassium salt of hydroxy-ethane sulfinic acid;

20 parts of sodium tetraborate; and

50 parts of sodium hydroxide.

The still m'oist fabric is led through the following solution heated to C. for the heat treatment:

730 parts of Water;

200 parts of anhydrous sodium sulfate; 20 parts of sodium tetraborate; and

20 parts of sodium hydroxide.

The period of treatment in this solution lasts for 40 seconds. The finishing lofi, such as oxidation, soaping and rinsing, of the print takes place as in Example 1.

Gray prints on a white ground are obtained.

Example 8 A cotton fabric is printed with the following paste:

70 parts of a yellow vat dyestufi, for example Vat Yellow .2, C.-I. 67300 (Color Index, 1956, volume 2, page 2428) in the form of a 20% aqueous paste; 30 parts of water; 600 parts of a 4.5% carob bean flour ether thickening;

and 300 parts of a 10% wheat starch paste (making 1000 parts in all).

After printing and drying, the following thickened solution of reducing agent is printed on by means of a roller engraved over the whole surface:

700 parts of water;

parts of a 6% tragacanth mucilage;

200 parts of a 40% solution of the sodium salt of hydroxy-ethane sulfinic acid; and

60 parts of sodium hydroxide.

The fabric is then treated for 35 seconds in air-free steam at C. without the use of excess pressure. The finishing off of the print takes place according to Example 1.

A brilliant greenish-yellow print is obtained on a white ground.

1 to 3% of sodium tetraborate may also be added to '7 the thickened solution of reducing agent for the coagulation of the carob bean flour ether thickening.

Example 9 The printed and dried fabric is prepared with the following solution of reducing agent on the two-roller foulard:

750 parts of water; parts of a yellow vat dyestuff, for example Vat Yellow 1, Cl. 70600 (Color Index, 1956, volume 2, page 2427) in the form of a 20% aqueous paste;

200 parts of a 40% solution of the sodium salt of hydroxy-ethane sulfinic acid;

50 parts of sodium hydroxide; and

15 parts of sodium tetraborate.

The fabric is then treated for 30 seconds in air-free steam at 110 C. without excess pressure. The finishing off of the steamed fabric is carried out as in Example 1.

A red print on a yellow ground is obtained.

The solution of reducing agent containing vat dyestuff may also be thickened with 100 parts of a 6% tragacanth mucilage while omitting the same amount of water, and this thickened solution applied by means of a roller engraved over its whole surface.

Example 10 A white cotton fabric is printed according to the following prescription:

50 parts of a yellow sulfur dyestulf, for example C.l. Sulfur Yellow 5 (Color Index, 1956, volume 2, page 2365);

parts of crystallized sodium sulfide;

135 parts of water;

600 parts of 6% tragacanth mucilage; and

200 parts \of 10% wheat starch paste (making 1000 parts in all).

After printing and drying, the fabric is sprayed with a solution of 900 parts of water;

100 parts of a 40% aqueous solution of the sodium salt of hydroxy-ethane sulfinic acid; and

50 parts of sodium hydroxide.

The still moist fabric is supplied continuously to a steamer and treated therein for 45 seconds in air-free steam at 110 C. The finishing off of the print, such as oxidation, soaping and rinsing, takes place as in Example 1.

A yellow print is obtained on a white ground.

Instead of the said yellow sulfur dyestuif there may also be used a brown sulfur dyestuff, for example C.I. Sulfur Brown 16, CI. 53285 (Color Index, 1956, volume 2).

In this case a deep brown print is obtained on a white ground.

Example 11 A white cotton fabric is printed with the printing paste described in Example 8 and dried. Then 50 parts of sodium hydroxide;

15 parts of sodium tetraborate; and

100 parts of the di-zinc salt of hydroxy-ethane sulfinic acid are added to 1000 parts of water. The mixture is stirred occasionally during the course of 10 minutes and then allowed to stand for 30 minutes. During this time the readily soluble sodium salt of hydroxy-ethane sulfinic acid forms from the diflicultly soluble di-zinc salt. The solution is carefully decanted from the sediment. With the solution of the sodium salt of hydroxy-ethane sulfinic acid containing sodium hydroxide and sodium tetraborate thus obtained, the fabric is prepared on the tworoller foulard and subsequently steamed for 20 seconds in air-free steam at 105 C. The finishing olf, consisting of oxidation, soaping and rinsing, takes place as described in Example 1. A yellow print is obtained on a white ground. The same result is obtained when, instead of being subjected to the steaming process lasting 20 seconds, the prepared fabric is led over a drum heated with steam with the fabric lying closely against the surface of the drum and protected from the action of atmospheric oxygen by being covered with a heat-stable elastic rubber or plastic cover, this heat treatment being allowed to last for 20 seconds.

Example 12 A white cotton fabric is printed with the following printing paste and dried:

30 parts of a violet vat dyestuff, for example Vat Violet 1, CI. 60010 (Color Index, 1956, volume 2, page 2479) in the form of a 15% aqueous paste;

120 parts of water;

600 parts of a 4.5% carob bean flour ether decoction in water;

200 parts of a 10% wheat starch paste; and

50 parts of sodium hydroxide (making 1000 parts in all).

Then

20 parts of sodium hydroxide;

87 parts of the di-Zinc salt of hydroxy-ethane sulfinic acid; and

15 parts of sodium tetraborate are added to 1000 parts of water. It is stirred occasionally during the course of 10 minutes and the mixture then allowed to stand for 30 minutes. After this period, the solution of the sodium salt of hydroxy-ethane sulfinic acid containing sodium hydroxide and sodium tetraborate is carefully decanted from the sediment and the fabric is prepared therewith. Then it is treated for 30 seconds in air-free steam at 105 C. The finshing off, consisting of oxidation, soaping and rinsing, takes place as described in Example 1. A violet print is obtained on a white ground.

The di-zinc salt of hydroxy-ethane sulfinic acid may also be replaced by parts of the more readily soluble mono-zinc salt of hydroxy-ethane sulfinic acid if 27 parts of sodium hydroxide are used instead of 20 parts.

Example 13 A white cotton fabric is printed with the following printing paste and dried:

30 parts of a violet vat dyestuif, for example Vat Violet 1, 0.1. 60010 (Color Index, 1956, volume 2, page 2479) in the form of a 15 aqueous paste;

50 parts of Water;

700 parts of a 4.5% carob bean flour ether decoction in water; and

220 parts of a 10% wheat starch paste (making 1000 parts in all).

Then the following are introduced into 900 parts of water at intervals of 10 minutes between each addition:

parts of potassium carbonate;

100 parts of the calcium salt of hydroxy-ethane sulfinic acid 30 parts of sodium hydroxide and 15 parts of sodium tetraborate,

with light stirring and the mixture is allowed to stand for 1 hour. In the course of this time, the potassium salt of hydroxy-ethane sulfinic acid, which is readily soluble in water, forms from the calcium salt which is diflicultly soluble in water, and calcium carbonate remains as a precipitate difiicultly soluble in water at the bottom of the vessel. The supernatant solution is decanted from the sediment and the fabric is prepared with the resultant solution of the potassium salt of hydroxyethane sulfinic acid containing sodium hydroxide and sodium tetrab orate with the aid of a two-roller foulard and then steamed for 30 seconds in air-free steam at 110 C. The finishing 01f, consisting of oxidation, soaping and rinsing, takes place according to Example 1. A violet print is obtained on a white ground.

For the production of the above described preparation solution there may be used, instead of the calcium salt, also the corresponding amount of the barium salt of hydroxy-ethane sulfinic acid. The same result is obtained under otherwise unchanged working conditions.

We claim:

1. In a two-phase printing process for printing textile materials with a dyestuff selected from the class consisting of vat dyestuffs and sulfur dyestuffs wherein said textile material is treated in a first stage by printing thereon a composition containing said dyestuff and a thickening agent and then drying said textile material and in a second stage by applying a reducing agent to said textile material and then heating for a short period of time sufficient to fix said dyestuif on said textile material, an alkaline agent also being applied to said textile material in at least one f said two stages, the improvement which comprises: using as the reducing agent in said second stage an alkali salt of a hydroxyalkyl sulfinic acid with from 2 to 4 carbon atoms, and heating said textile material in said second stage for a period of time of about 10 to 60 seconds at a temperature between 80 C. and 200 C. whereby said dyestufl is fixed on said textile material.

2. An improved pnocess as claimed in claim 1 wherein the heating temperature is between about 90 C. and 120 C.

3. In a two-phase printing process for printing textile materials with a dyestufi selected from the class consisting of vat dyestulfs and sulfur dyestufis wherein said textile material is printed in a first stage with a composition containing said dyestufi and a coagulable thickening agent and then dried, and the print is fixed in a second stage by applying a solution, containing an alkaline agent, of a reducing agent and then heating for a period of time of about 10 to 60 seconds at a temperature between about 80 C. and 200 C., the improvement which comprises: employing as the reducing agent in said second stage an alkali salt of a hydroxyalkyl sulfinic acid with from 2 to 4 carbon atoms.

4. In a two-phase printing process for printing textile materials With a dyestufi selected from the class consisting of vat dyestufis and sulfur dyestuifs wherein said textile material is printed in a first stage with a composition containing said dyestuff, an alkaline agent and a coagulable thickening agent and then dried, and the print is fixed in a second stage by applying a solution of a reducing agent and then heating for a period of time of about 10 to seconds at a temperature between about C. and 200 C., the improvement which oomprises: employing as the reducing agent in said second stage an alkali salt of a hydroxyalkyl sulfinic acid with from 2 to 4 carbon atoms.

5. In a two-phase printing process for printing textile materials with a dyestuff selected from the class consisting of vat dyestuffs and sulfur dyestuffs wherein said textile material is printed in a first stage with a composition containing said dyestuff and a non-coagulable thickening agent and then dried, and the print is fixed in a second stage by applying a solution, containing an alkaline agent, of a reducing agent and then heating for a period of time of about 10 to 60 seconds at a temperature between 80 C. and 200 C., the improvement which comprises: employing as the reducing agent in said second stage an alkali salt of a hydroxyalkyl sulfinic acid with from 2 to 4 carbon atoms.

6. In a two-phase printing process for printing textile materials with a dyestuif selected from the class consisting of vat dyestuffs and sulfur dyestufis wherein said textile material is printed in a first stage with a. composition containing said dyestufi, an alkaline agent and a non-coagulable thickening agent and then dried, and the print is fixed in a second stage by applying a solution of a reducing agent and then heating for a period of time of about 10 to 60 seconds at a temperature between about 80 C. and 200 C., the improvement which comprises: employing as the reducing agent in said second stage an alkali salt of a hydroxyalkyl sulfinic acid with from 2 to 4 carbon atoms.

7. A improved process as claimed in claim 1 wherein the reducing agent is the sodium salt of hydroxy-ethane sulfinic acid.

8. An improved process as claimed in claim 1 wherein the reducing agent is the potassium salt of hydroxyethane sulfinic acid.

References Cited in the file of this patent UNITED STATES PATENTS 2,164,930 Lubs July 4, 1939 2,276,704 Schneevoigt. Mar. 17, 1942 2,315,514 Fox Apr. 6, 194-3 2,412,909 Potter Dec. 17, 1946

Claims

1. IN A TWO-PHASE PRINTING PROCESS FOR PRINTING TEXTILE MATERIALS WITH A DYESTUFF SELECTED FROM THE CLASS CONSISTING OF VAT DYESTUFFS AND SULFUR DYESTUFFS WHEREIN SAID TEXTILE MATERIAL IS TREATED IN A FIRST STAGE BY PRINTING THEREON A COMPOSITION CONTAINING SAID DYESTUFF AND A THICKENING AGENT AND THEN DRYING SAID TEXTILE MATERIAL AND IN A SECOND STAGE BY APPLYING A REDUCING AGENT TO SAID TEXTILE MATERIAL AND THEN HEATING FOR A SHORT PERIOD OF TIME SUFFICIENT TO FIX SAID DYESTUFF ON SAID TEXTILE MATERIAL, AN ALKALINE AGENT ALSO BEING APPLIED TO SAID TEXTILE MATERIAL IN AT LEAST ONE OF SAID TWO STAGES, THE IMPROVEMENT WHICH COMPRISES: USING AS THE REDUCING AGENT IN SAID SECOND STAGE AN ALKALI SALT OF A HYDROXYALKYL SULFINIC ACID WITH FROM 2 TO 4 CARBON ATOMS, AND HEATING SAID TEXTILE MATERIAL IN SAID SECOND STAGE FOR A PERIOD OF TIME OF ABOUT 10 TO 60 SECONDS AT A TEMPERATURE BETWEEN 80* C. AND 200*C. WHEREBY SAID DYESTUFF IS FIXED ON SAID TEXTILE MATERIAL.