EP0044601A1

EP0044601A1 - Process for discharge printing of polyester materials

Info

Publication number: EP0044601A1
Application number: EP81200822A
Authority: EP
Inventors: Ronald Johannes Spierdijk; Willem Laurens Veltman; Louis Leonard Weerkamp
Original assignee: EPEC-DINON
Current assignee: EPEC-DINON
Priority date: 1980-07-18
Filing date: 1981-07-20
Publication date: 1982-01-27
Also published as: NL8004160A; DE3174709D1; ATE20100T1; JPS57101086A; EP0044601B1

Abstract

Composition for discharge printing of textile materials in one step consisting of cellulose fibers, such as cotton and synthetic fibers, such as polyester, containing thiourea as an agent discharging dischargeable dyes. Thiourea is present in an amount of not more than 5%. For rotation film printing the composition together with another composition is applied on to the textile material, whereafter the whole is subjected to a steam treatment at a temperature comprised between 150 and 180°C.

Description

The present invention relates to a composition for the discharge printing of textile materials, more particularly polyester, triacetate, acetate and a mixture of said textile materials with natural fibres
Discharge printing is widely adapted for applying colored patterns on textile materials, whereby a first dye is applied to a layer of textile material followed, on this first dye, by a composition that contains a . substance which breaks down the first dye present. When a composition is worked which only contains the chemical substance which decomposes the first dye, white or uncoloured parts are obtained on the textile material.
When the unprinted composition with the discharging agent contains not only the discharging agent but also additionally a dye that is proof against the discharging agent, another second colour is obtained at the place where the composition is applied.
This method of printing textile materials is relatively complicated, since light prints are difficult to see on a dark background, so that matching difficulties may occur. The more that heavier qualities are used, the greater the risk of the position of the contours of small motifs being unclear and diffuse on the large background. The cause of this is the high pressure that must be set on a printing machine in order to obtain any effective penetration of the print into the textile material.
The production process of discharge printing of textile materials is achieved by a so-called two-stage method and proceeds as follows.
The dischargeable base c lours are dyed, sized or preprinted and then dried, after which the textile material is printed with the aid of a rotary, screen, roller or litho printing machine while applying the compostition containing a discharging agent which may additionally contain dyes which are proof against the agent. The whole is then dried, fixed and further treated.
With this known process, use is generally made of stannous II chloride as discharging agent, but other metal compounds may also very easily be used, such as e.g. zinc formaldehydesulfoxylate.
The concentration of the discharging compound to be wsed is relatively high (100 g per kg of discharging agent- containing composition or more) owing to the lack of the mechanical effect (cover print) and the hydrophobic nature of artificial fibres.
The application of a high concentration of discharging agent present the disadvantage that

a) a small dying range is obtained since, the more reducing agent is used, the less the dyes become dischargeproof. In practice, this results in discharge-proof dyes which are relatively dull in colour.
b) When the dyes are fixed on the textile material, hydrochloric acid escapes during this reaction mechanism which gives rise to high corrosion and attack of the metal of the steamer in which the fixation takes place.
c) Stannous chloride is an expensive product so that the process is very costly.

The two-stage method as applied has the disadvantage; in particular, that a high percentage of waste occurs, which is a consequence of the fact that the process is difficult to check and when the first dye applied is dried, certain parts may be fixed so that the discharge print fails when the composition containing the discharging agent is printed on the first dye. Furthermore, the opportunities for design and artistic work are restricted since the print with the compostion containing the discharging agent and the first dye cannot be printed to match in relation to each other, while, finally, this process can virtually be applied only on thin polyester materials.
Having regard to the above disadvantages of the two-stage method, processes have been sought in which, during printing, the first dye is applied in one stage together with the print of the composition containing the discharging agent. By this means, the following advantages are obtained.
a) The textile material need be passed over a printing machine once only, while drying after applying the first dye-containing composition can be omitted; this leads to major economic advantages.
b) Since the drying of the first colour-containing composition is superfluous, no additional problems can result with parts of the textile material containing dye-, already fixed, so that the percentage of waste is reduced.
c) The composition containing the first dye and a discharging compound can be printed in relation to each other so that the opportunities for design and artistic work are much greater. In particular, this process allows designs hitherto impossible to be printed onto textile materials.
d) Through an appreciably smaller use of stannous II chloride important economic advantages are obtained.
e) Owing to the fact that less stannous II chloride need be used, less corrosion of the installation is also likely.
f) A more extensive range of dyes can be worked with as more dyes will be proof to the discharging agent owing to the smaller quantities of the latter, so that the opportunity of printing light tints is also gained.
g) Single-stage printing allows thicker, coarser polyester qualities to be worked with.
h) A multi-coloured design can be obtained by making use of masks both in the stencils for the first colour and the stencils for applying the compound containing the discharging agent, which may contain a second colour which is proof against the discharging compound.
It will be clear that a very great number of possibilities of colour patterns can be achieved by including dischargeable and discharge-resistant dyes in the composition for applying the first dye. With these single-stage methods known hitherto, use is made of a first dye-containing composition on to which a second composition is applied which contains a thickener, in addition to e.g. zinc- formaldehydesulfoxylate, also known as "Decroline". The difficulty that arises with this process is that a relatively large quantity of decroline must be used which has a detrimental effect on the colour pattern or design eventually obtained.
It is a primary object of the invention to provide a composition for the discharge printing of textile materials, preferably in a single stage, by applying a discharging agent whereby the above disadvantages do not arise and,, in particular, improved colour patterns can be obtained with an appreciable saving in raw materials. The opportunity is also created for discharging textile materials without stannous II chloride, depending on the dyes and materials to be processed.
This is attained according to the invention by a composition for discharge printing textile materials, which does not coagulate with the composition and a discharging agent, characterized in that the composition contains as discharging agent, at least one organic composition exerting a reducing effect on organic dyes.
The composition may effectively include an organic compound exerting a reducing effect with the formula R₁ ^R ₂ ^{C -} X or R₁R₂C - XH where X is a sulphur or selenium atom, the group R₁ an amino group whether substituted or not and the group R₂ consists of an amino group if there is a double bond between the carbon atom and the X atom or consists of an imino group if there is no double bond between the carbon atom and the X atom.
The composition preferably contains an additional discharging agent in the form of a salt of a metal of the second to fourth groups of the periodic system. However, this is unnecessary if suitable recipes are applied.
The composition may with particular advantage contain as a discharging agent a halogen compound of a bivalent metal, in particular zinc chloride, and yet more advantageously a halogen compound of a quadrivalent metal, in particular stannium, which stannium compound is applied in the form of stannous II chloride.
The thickeners applied in the composition according to the invention may effectively consist of cellulose or starch derivatives thickening with water. Other solvents can also be included in the composition such as e.g. benzine, in which case semi-emulsions are obtained.
A composition may effectively be used for printing which contains 0,1 to 4% of a metal salt, more particularly 0,1 to 2% and 0,5 to 10% organic discharging agent, still more particularly 1 to 5%_and more effectively 0,5 to 1% of a metal salt, preferably stannous II chloride and/or 0,5 to 5% thiourea.
The composition according to the invention is particularly used for rotation film-printing of textile materials containing synthetic and natural fibers, particularly cellulose fibers (cotton) and polyester.
The invention will now be explained with the aid of several examples.

Example I

Discharging composition for e.g. dispersed dyes

360 g of thickener (12% solution) is mixed with 40 g-of emulsifier (12,5% solution), 16 g of sodium acetate and 2 g of citric acid and 48 g of thiourea.
Further, 10 g of carrier and 320 ml of terpentol are added to this composition, together with a desired quantity of discharge-proof dispersed dyes and 20 to 40 g of stannous II chloride (depending on the properties and concentrations present of the dischargeable dyes or those to be discharged). This is filled up to 1000 g with water or another solvent.

Example II

Discharging composition suitable for e.g. dispersed dyes

The composition described in Example I is prepared but without 20 - 40 g stannous II chloride. Instead of stannous II chloride 30 g of "Solutionsalz" or an identical product and 30 g of Lyogene V or an identical product is added. It is filled up to 1000 g with water.

Example III

Discharging composition suitable for dispersed reactive dyes

The composition described in examples I or II is taken but the quantity of citric acid is increased to 50 g and 80 g of polyethyleneglycol (specific weight 300) is also added, after which discharging on to polyester/cotton is possible.

Example IV

Discharging composition suitable for pigment dyes

700 g of an acid pigment cover printing paste is taken, to which is added 20 g of sodium acetate, 20 g of fixation agent, 50 g of tylose MH 300 (7° solution), 50 g of citric acid and 50 g of thiourea. A certain quantity of discharge-resistant pigment dye and 20 - 40 g of stannous II chloride (depending on the properties and dye concentrations present of dischargeable dyes or dyes to be discharged) is further added to this composition. It is filled up to 1000 g with water. By means of this printing paste cover printing is possible on polyester/cotton with discharge-resistant pigment-dyes.

Example V

Discharge composition suitable for pigment dyes

The composition described in Example IV is taken but without 20 - 40 g of stannous II chloride and, instead, the products named in Example II are added.

Example VI

Printing of textile

A layer of one of the discharge-resistant printing

pastes as described in one of the examples I to V is applied to the textile material to be printed (50% cotton fibre and 50% polyester fibre) and a print overlayer is applied to this of a known printing paste with dischargeable dyes.
Both printing pastes are printed wet on wet in a single stage with the aid of a printing machine.
The cloth is then dried, fixed at e.g. a temperature of 170°C within a period of e.g. 10 minutes, after which the textile material is further treated.
It is recommended that the printing paste according to the invention be first applied to the textile material and then the paste with dischargeable dye, as this produces optimum results.

Claims

1. Composition for the discharge printing of textile materials, which composition contains a thickener
not coagulating with the composition, and a discharging agent, characterized in
that the composition contains as discharging agent at least one organic compound exerting a reducing effect on organic dyes.

2. Composition as claimed in claim 1, characterized in
that the composition contains an organic compound exerting a reducing effect of the formula R₁R₂C = X or R₁R₂C - XH, where X constitutes a sulphur or selenium atom, the group R₁ an amino group whether substituted or not and the group R₂ consists of an amino group if there is a double bond between the cprbon atom and the X atom or consists of an imino group if there is no double bond between the carbon atom and the X atom.

3. Composition as claimed in claim 1, characterized in
that the composition contains no more than 10% of the organic compound exerting a reducing effect, preferably 0,1 to 5%, said organic compound being preferably thiourea or isothiourea.

4. Composition as claimed in claim 1, characterized in
that the composition contains an additional discharging agent, preferably a salt of a metal of the second to fourth group.of the periodic system.

5. Composition as claimed in claim 1, characterized in
that the composition contains a halide of a metal of the second to fourth groups of the periodic system, particularly a halide of zinc or a stannous II halide, more particularly stannous II chloride as an additional discharging agent.

6. Composition as claimed in claim 1, characterized in
that the composition contains one or more of the following compounds:

a) a thickening agent which thickens with water;

b) a thickener which consists of a cellulose or starch derivative;

c) a non-dischargable dye.

7. Composition as claimed in claim 1, characterized in that the composition is suitable for printing on textile materials in a single step.

8. Process for printing textile materials, preferably in a single step, by applying at least one first composition which contains a dischargeable dye and another composition which contains at least one discharging agent for the said dischargeable dye, characterized in
that the other composition is a composition according to one or more of the preceeding claims.

9. Process as claimed in claim 8, characterized in that the other composition is first applied on to the textile and on it the first composition containing the dischargeable dye.

10. Process as claimed in claim 8, comprising one or more of the following measures:

a) after applying the first and another composition, the whole is subjected to heat treatment at a temperature exceeding 80°C and less than the decomposing temperature of the textile material, preferably to a heat treatment at a temperature of 150 to 180°C, more preferably a steam treatment;

b) after the dyes have been fixed the textile material is further treated or further cleaned;

c) the textile material contains at least synthetic fibres;

d) the textile material is a mixture of cellulose and synthetic fibres, more particularly polyester fibrest

e) the first and another composition are substantially simultaneously applied.