CA1051613A - Process for fixing prints and dyeings - Google Patents

Abstract

PROCESS FOR FIXING PRINTS AND DYEINGS
Abstract of disclosure A process for fixing dyeings and prints on cellulose fiber material and mixtures thereof with synthetic fibers according to a two-phase method, wherein the printed or padded material is coated with a foam, the liquid phase of which is the alkaline fixing liquor necessary for the fix ation of the dyes in said two-phase fixing processes.

Description

/ ~ ~ ~ 092 The present invention relates to a procsss ~or ~i~ing prints and dyeings.
Two phase methods for the development of vat dyes, leuco ester vat dyes and reactive dyes are liable to ~if~icult-ies occuring in the second step of the process, i.e. in the application of the fixing chemicals onto the padded or printed textile material; the adequate dosing of the liquor fesd containing these chemicals always raises problems.
Known methods in this field are the padding, slop-padding, cross-printing and spraying methods. The high require-ments on an even application of the chemicals include the great risk to supply, for example, too much padding liquor to the material; which might cause the prints to flow, thus blurring the design on the goods~ To avoid this risk, con-siderable amounts of inorganic salts are added ~o the fixing liquor in order to reduce the solubility of the applied dyes of all the said dyestuff classes. The amount of liquor really necessary for fixing the dyes is generally substaniially lower than the total amount o~ liquor hitherto applied by conventional methods. Any difficulties, including those of sewage water pollution, which are caused by those salt additi ons could therefore be avoided by reducing the amount of the liquid phase applied.
According to German Offenlegungsschrift NosO 2,1l~5,827 and 2~243~865, it is knowII that textile materials can be dyed or finiqh0d batchwlse usin~ a foam. Also, the Periodi-cal "Textilvered]ung" 6 ~1971), No. 11, pages 708 - 711, describes a process wherein piece goods can be dyed batchwise 29 by means of ~oamed-up dyestuff liqlors and using centripedal

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force. Finally, accordlng to German Offenlegungsschrift No. 2,214,377, it has already been proposedi to apply dyes and/or finishing agents as well as chemicals op~lonally required for *he fixing thereof onto flat textile arti-cles in the form of a foam. This latter method, however, neither requires nor benefits from the advantage of a low amount of liquor to be applied; more-over, that foam serves for dyeing and finishingJ optionally a~ the same tlme, and may produce, where required, also design and multicolor effects. Mi~ration may be avoided in this ~anner. Although that method is a single-step dyeing process, it is very difficult to ob~ain even dyeings by it, slnce the hand-ling and uniform appllcation of the foam ~ and thus the entlrely steady transfer of liquor to the material - present considerable difficulties in practice.
According to the present invention there is provided a process for fixing dyeings and prints on cellulose fiber material and mixtures there-of wlth synthetic fibers according to a ~wo-phase method, wherein a printed or padded materlal ls coated with a foam, the llquid phase of whlch is the fixing liquor necessary for the fixation of the dyes in said two-phase flxing processes.
Alth~ugh, according to this novel application technique, a certain increase in concentration of ~he fixing agent in the liquid phase of the foam is necessary, the total amount of fixing liquor is reduced. As a whole, it is thus possible, when applying for example 20% of liquid phase in the form of, for example, a 5 to 15% foam, to reduce the amount of chemicals to, for example, 10% of the amount hitherto used.
The liquid phase of the foam may contain up to 100 g~L

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_OE ~4/~ 092 ~L~5~L3 of sodium carbonate, ZOO cm3 of NaOH (38 Bé)/L or 400 cm3 of water glass (50 Bé)/L. Normal:Ly, a standardized alkaline liquid phase containing 80 g of sodium carbonate and 5 g of so-~
dium hydroxide in 1 l water is used.
The fixing chemicals used as a foam according to the in-vention are moreover distributed evenly and satisfactorily on the substrate and the extremely low water content of the foam ~ in extreme cases, it is even less than l~ of water - per-mits the amount of chemicals to be dosed quite exactl~. The consistent foam never has the nature of a liquid, and there-fore prints produced by this technique will not have blurred outlinesj nor will a padded dyestuff be dissolved and removed~
According to this technique, also prints, for example on a gasoline emulsion basis 9 may be treated with the foam or with a foamed emulsion. --To assure a satisfactory operation and an even and uni-form application of foam according to the invention9 it is advantageouis to maintain a sufficiently high foam concentration lcvel on the material~ while bearing in mind that more foam maans more liquid and hence the risk of blurring the sharp out-lines of the prints, In such cases, it is advisable to add up to 10~ of inorganic salts, for example sodium chloride or Glauber salt, to the liquid phase of the foam9 or to use coagulating thickeners in the printing pastes.
In contradistinction to the above-cited methods pertaining to the state of the art, the dyestuff solutions are applied according to the invention onto the textile material generally ~ in the usual manner by padding or printing opera~ions. Only 29 the alkaline agents or acids required for fixing the dyes are ~ 4 -.1,. . . .. ~ . , . ~ . . :

~2 5~3 applied as a foam, thus assuring a more economic dosing of the alkali amount than hitherto possible in the second phase of the application method. According to conventional padding methods using alkaline fixing liquors, a minimu~ of 50% of water is applied to the material. This water has to be sn-riched with otherwise dispensible salts, in order to prevent migration of the dyes. Reducing this amount of water thsre-~or~means dilu$ing the salt solutions, thus saving chemicals for two reasons: Less liquor and a lower concentration of salt.
In contradistinction to a single-step application Or dyes and fixing auxiliary according to German Offenlegungs-- schrift No. 2,214,377, the two-step operation according to this invention safeguards stability of the padding liquors and printing pastes right from the startO Neither are there any pr~blems of levelness as mentioned for the prior art methods, since the aqueous padding liquor and printing pastes are, in any case, applied in uniform mannerO The application of the ~ixing chemicals in the foam state (second stop) affects the uniformity of dyestuff fixing only inasfar as, over the whole length and width of the material, merely a minimum of r~ecf~7tc~/
fixing chGmical is required, a ~u~Yu-~y~ proble~ which is - very easy to solve. Overdosing the fixing chemicals does not detrimentally influence the dyestuff yield.
The present process is advantageously carried out accord-ing to known methods, for example by preparing a stable ("long-life") foam by means of a foam fire extinguisher, with-out having to take the time of spontaneous foam break-down 29 into regardO Suitable foaming agents are preferabl~ produc~s .... ~: :
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' ' ' on the basis of triethanolamine alkyl sulfates of the general formula R - O - S03HN(CH2 ~ CH2 ~ OH)3 alkyl polyglycol ether sulfates of the general formula R - O - (CH2 - CH2 ~)n - S03X, in which R stands for an alkyl group of 12 to 14 carbon atoms, X for an alkali metal or ammonium ion, and n for an integer of 2 to 5, and mixtures thereof at any mixing ratio. As solvents suitable for the preparation of these foam concentrations, butyl diglycol is preferably used, and the foam is stabilized by means of small amounts of a fatty alcohol, for example lauryl alcohol. These foam concentrates are added in a concentration of ; -0.5 to 3% of the aqueous fixing liquor to produce a long-life foam.
According to the broadest aspect of the invention there is provided a process for fixing dyeings and prints on cellulose fiber material and mixtures thereof with synthetic fibers according to a two-phase method, wherein a printed or padded material is coated with a foam, the liquid phase of which is the fixing liquor necessary for the fixation of the dyes in said two-phase fixing processes.
The fixing process of the invention is predominantly used for fixing dyeings and prints produced with reactive dyes. The alkali required for the fixation of reactive dye-stuffs is applied in the form of a foam, the liquid phase of which is the solution of an aIkali metal hydroxide, silicate or sodium carbonate.
When vat dyes are used, a sodium carbonate reducing system may also be foamed up according to the invention.
To fix and develop dyes made of combinations of naphtho-: . ' . -A

~2 1~ 3 lates and stabilized diazo compounds~ for exampls a 5~ foam containing 10~ of formic acid in the liquid phase, is applied.
A passage of the so-treated material through tha air within 60 seconds is sufficient for the de~elopment of the dye on the fiber, on which it has been printed.
~hen fabrics that have been printed with vat pigments are , s~pplied with fixing chemicals, it is of speclal importance to add an adequate foam-destroying agent to the printing pastes, since the air-containing foam should have collapsed prior to entering the steàmer, so that the detrimental in-~ fluence of enclosed air is excluded.
A device for carr~ing out the process of the invention is illustrated diagrammatically be way of example in the accompanying drawings. In these drawings, ~igs. 1 to 4 are cross-sectio~al YieWs of some embodiments o~ the de~ice.
Referring to these ~igures, the reference numbers have tha following meanings-1 material web 2 endle~s circulating rubber cloth

3 drivable transport rollers

4 foam tank or box

5 foam containing treating agent

6 contact area of foam and material

7 cover sheet for Yarying length of contact area 6

8 doctor blade which is adjustable in height

9 foam feeder pipe

10 guide rollers for the material web

11 slit nozzle for foam outlet 29 12 slant " ,:, ,, . ., .:
, ' ~' 13 trough lOS1~13 14 foam-applylng roller According to an advantageous e~bodiment af the new process, the foam containing the treating agent is put in a box on high wheels and is retained by means of a scarcely wettable doctor blade at a pre-determined height above the material.
It has pro~ed to be advantageous to feed the foam to this box in a continuous or discontinuous manner or to produce it steadily or batchwise in the lower portion o~ the box. In these boxes or tanks, the material conducted by a roller or a . 1 . .
transport belt driven by a roller system is immersed more or 14ss deeply ln the foam. With these two ~ariants, the amount of foam absorbed oan ~ greatly varied by the contact time between the foam and the matarial web to be treated. In a simple manner, this is done as illustrated in Fig. 1 by covering part of the contact area of tha material and the ~oam supply in the case of thin material requiring less foam .
With the contact area varying, it is easier-to adapt it to a change in the transport speed of the material. In the sim-~ , - plest case, the material is supplied with foa~ using a slant which is usually the doctor blade or which passes into a doc$or blade. Two of such arrangements are illustrated in ~igs. 2 and 3. Fig. 4 finally shows a pair of rollers as the application arrangement for the foam. In this arrangement, the ~oam is supplied onto tha surface of the one roller which carries it along while rotating, and in the nip of the rollers the foam is transferred onto the material web which is conducted ro~nd the other roller. The distanc~ between tho 29 two rollers determines the thiokness of the foam layer ~height - . . . . . . . .. .. . .. ... . .. ... . . . .. . . . . . .

~l)51~i~3 of foam) on the material.
The following Examples illustrate the in~ention, the dyes used therein havebeen taken from Colour Index Numbers given in the 3rd edition of this Inde~ from 1971, the percentages being by weight unless stated otherwise.
E X A M P L E 1:
A cotton knit fabric having a weight o~ 200 g/~ was - printed with a printing.paste containing 15 g of the dyestuff Reactive B~ 19 - CoI~ No. 61 2009 2 g of primary sodium phosphate, - 483 g of sodium alginate (in an aqueous 5% solution) and ~00 g of water to make up a ~olume of 1000 g.
Upon drying, the fabric was supplied in the arrangement illustrated in ~ig. 4 with a layer of.an aqueous 5% foam having a liquid phase of 10~ of a 30~ sodium hydroxide solution and 1% of a foam concentrate on a triethanolamine-coco fatty sulfate basis. The liquor pickup was 20~ b~ weight which means that ~ ml of the 30~ sodium hydroxide solution was brought on 1 m2 of the fabric.
The foam was applied at a distance of about 1.cm between the 'cwo separately driven rollers, which rsgulated the height of the ~oam layer. The two rollers may also be driven at . different speeds9 the rollsr that carried the foam running at a higher speed~ In such a case, one roller may be dri~en ~ by the other one. In the simplest case, the drive is trans-ferred by pressing the rollers one against the other, after a cloth strip of at least 20 cm width has been wound around 29 the two ends of one roller. This clo'ch winding has to be as , .
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~2 ~5~3 thick as to match the distance bet~een *he two rollers at ths portions conducting the material.
The material provided with a foam layer was conveyed to a steamer, after having left the application arrangement, and was treated with steam at 100 C for ZO seconds. Upon washing and drying, a blue print on a whi*e bottom was ob-tained.
E X A M P L E 2:
A cotton towelling material having a weight of 400 g/m2 was printed with 25 g of the dyestuff Vat Orange 7 - C.I. No.
- 71 105. In addition to this dyes$uf~, the printlng paste contained 50 g of starch ether (in the form of an aqueous 10% solution) as a thickener and 0.5 g of an anti-foaming agent on a silicone basis~
After having le~t the printing unit, the still moist material was coated in an arrangement as illustrated in Fig.
1 with an aqueous 5~ foam prepared with an addition of 2% of a 1~1 mixture of triethanolamine-coco fatty sulfate and :
ammonium salt of coco fatty acid triglycol ether sulfate.
The liquid phase of this ~oam oonsisted of a 5~ sodium hy~
droxide solution, in which another 5~ of sodium dithionite had been dis~olvedO The layer thickness of the foam was 1.6 mm as controlled by the adjusted height of the doctor blade illustrated in Fig. 1. Immediately after ha~ing left the foam supply box, the foam collapsed and the aqueous phase was absorbed by the printed fabric. The ~quor pickup was 20% whioh means that 80 ml of the 5% sodit1m hydroxide solution was brought on 1 m of the material~
Z9 Upon application of the foam, the material was at once . . .

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, : ' : , . , - ~ :' . : .: .' E 7 4/~ 092 entered into a steamer,without being dried1and treated with steam at 120C for 1 minute. Upon rinsing, oxidizing and washing the material thus treated, a bright oranga print on a white bottom was obtained.

X A-M P L E `3:
A linen mat~rial having a w~ight of 350 g~m was printed ! with the printing pas~ as disclosed in Example 1 using, how-ever, 15 ~ of the dyestuff Reactive Yellow 17 - C.I. No.
-18 852, and coated with the foam prepared as in Example 1 in the arrangement illustrated in ~ig. 3. The liquor pick-up was 15~ which means that 52.5 ml of the sodium hydroxide solution was brought on 1 m of the material. The thickness of the foam was approximately 1 mm.
The linen fabric, which had been coated with the foam and then treated with the doctor blade, was introduced into a heat channel at 60C, stored thcre for 10 minutes and then washed. A golden yellow design on a semi-white bottom was obtained .
E X A M P ~ E 4:
A mixture of 15 g of Azoic Coupling Component 2 - C.I. No. 37 505, and 10 g of p-nitro-aniline in the form of its diazonium salt, stabilized as a diazo amino compound, ~as dissolved in 1 l of a 2% sodium hydroxide solution, and the solution was thickened by means of locust b~an flour ether. A spun rayon fabric having a weight of 125 g/m2 was printed with this printing paste and dricd.
An aqueous 10~ formic~ acid was then foam~d up witll 1~2%
29 of a foam concantrate on the basis o~ ammonium salt of coco . ~
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H OE 7 4/P~ ~O~, ~S~ 3 ~atty acid triglycol ether sul~ate, to give an aqueous 5%
foam,and the foam WQS applled on the material by means of the arrangement illustrated in Fig. 2. The liquor pick-up was 30% which is a pick-up of 3.75 g pure formic acid on 1 m2 of tne fabric. The foam thickness was ca. 1 ~m.
After the residual foam had been removed by a doc~or blade, the material was exposed to air for 60 seconds, whilst the produced shade developed its full intensity. The development - of the dye may also be intensified by heatin~ with infrared rays. h red print on a white bottom was obtained.
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Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for fixing dyeings and prints on cellulose fiber material and mixtures thereof with synthetic fibers according to a two-phase method, wherein a printed or padded material is coated with a foam, the liquid phase of which is the fixing liquor necessary for the fixation of the dyes in said two-phase fixing processes.

2. A process as claimed in claim 1, wherein the padding liquor or printing paste contains a foam-destroying agent which causes the foam to collapse upon contact of the material with the foam.

3. A process as claimed in claim 1, wherein the cellulosic fibers and the cellulosic fiber portions in blended fabrics are dyed with vat dyes, leuco ester vat dyes, stabilized azo dyes or reactive dyes.

4. A process as claimed in claim 1 wherein the cellulose fiber material is dyed with reactive and vat dyes and said fixing liquor is alkaline.