EP0311796A1 - Method for wet treatment of sheet-like materials - Google Patents

Abstract

The device (100) for carrying out the method comprises a padder (10) in which the web (1) is provided with a first treatment liquor and squeezed to a moisture content of 60 to 100%. A gusset application device (20) is combined with the foulard (10), in which the web (1) is provided with an additional liquor application of 40 to 100%. The application takes place in an upright trough (9) in which the material web (1) is only in contact with a very small amount of constantly supplied treatment liquor (13). The trough (9) is sealed at the bottom by two inflatable hoses (17, 18) lying horizontally opposite one another on both sides of the web (1), which abut the web and strip off the treatment liquor carried by it to a predeterminable total moisture content. During dyeing operations, the web then runs into a damper (30) and a washing device (40).

Description

The invention relates to a method according to the preamble of claim 1 and a corresponding device.

The starting point of the invention were problems which have been pending for a long time in continuous dyeing with direct dyes (noun dyes) (see Fischer-Bobsien "International Lexicon textile finishing + border areas" 4th edition 1975, columns 419-422). The dyeing liquor can be applied in a foulard, so that the web is passed through the larger amount of dyeing liquid in the pool of the foulard. This has resulted in unavoidable end processes, both at the beginning and at the end of the web. When passing the first parts of the web through the fleet in the basin, parts of the fleet are towed out of the web, which cause a corresponding depletion of the fleet, which must be readjusted. It takes a certain amount of time before an equilibrium relationship has been established and the concentration of the fleet remains constant. By the time this condition is reached, an end run of 50 to 150 m has occurred. Such lengths of goods with a different and in particular not constant color tone cannot be used together with the rest of the goods are used, but are sold as lower qualities or over-dyed black. In any case, these end processes result in a certain previously unavoidable loss.

Another problem is the fact that the direct dyes do not fully absorb and the non-fixed portions on the web are washed out after steaming. The dye yield, i.e. the ratio of the dye actually fixed on the goods to the dye originally applied is far from complete, but is in the order of 60%. The undrawn 40% "go into the sewer" and represent not only a very significant cost factor, but also a difficult environmental problem, especially since many molecules of direct dyes contain complex-bound heavy metal ions, in particular copper ions, which are regarded as a dangerous waste water poison and with regard to their strict official regulations.

It is now known that the application of direct dyes to the goods can be improved by adding salts such as table salt or Glauber's salt. In this way, the proportion of the dye that is actually absorbed on the fibers can be increased and thus the loss of dye on the one hand and the environmental impact on the other hand can be reduced.

In the continuous process, however, the addition of salt to the dye bath in the foulard increases the end processes. The salt increases the drawability of the goods so that the eager dye takes up from the liquor and the amount of liquor at the beginning and towards the end shows even stronger and difficult to control changes in concentration. This can be used to improve the dye yield and the environmental impact So don't get involved in continuous dyeing without further ado.

Based on this particular problem, the invention has for its object to design a method and a corresponding device so that the interaction of the two treatment fleets starts in a controlled manner, that there are no changes in treatment loss due to changes in concentration in the second treatment fleet and that there is a more uniform length of the web Ceases treatment.

This object is achieved in its procedural aspect by the invention reproduced in claim 1.

The method is primarily considered for the treatment of flat fabrics. In such a web, the first treatment liquor is applied in some way and then squeezed to 60 to 120%. The moisture values always relate to the amount of treatment liquor in relation to the dry weight of the web to which the treatment liquor has been applied. A value of 120% is the upper limit of what can still be squeezed evenly in a squeezing device with interacting rollers; at higher moisture contents, the squeezing mechanism would have to be driven with line pressures so low that the uniformity of the squeezing would no longer be guaranteed and there would even be a risk of the rollers lifting off from one another in certain areas. On the other hand, such an amount of moisture can hardly be applied to a product web with effort that is justifiable in practice other than by impregnation or wetting of the product web with subsequent squeezing. Spraying is difficult to do evenly. The same applies to infusion, since the amount of liquid to form a even film is too low.

The second treatment liquor is now applied to the web loaded with the specified amount of liquid, in a special way. The material web should not be passed through a larger fleet, in which there is a risk of concentration changes due to the amount of treatment agent carried out by the material web. For this reason, when the second treatment fleet is applied, the web should only be in contact with the smallest possible amount of liquor, which is very quickly absorbed and transported away by the web and which is accordingly constantly renewed or supplemented by introducing fresh treatment fleets. Fresh liquor is therefore always applied to the web on both sides, through which no longer lengths of the web have yet passed. In this way, changes in concentration in the amount of treatment liquor in contact with the material web and corresponding differences in treatment failure can be minimized.

It is also important that the second treatment liquor is not squeezed off after application. By squeezing, no total moisture content can be set evenly, which is significantly above 120%. If squeezed after the application of the second treatment fleet, it would at best be possible to add a few 10% of the second treatment fleet, which in many cases is too little for the interaction of the two treatment fleets and the failure of the treatment. For this reason, the material web is stripped off after the second treatment liquor has been applied, so that the same amount of treatment liquid can be added in the order of magnitude as can be achieved with the first application and total moisture contents can be achieved, which are in the range of what the web of moisture can hold at all without the moisture dripping from the web or running down on it. Such loads of liquor, which have been pushed to the limits of the drip-free moisture content, are advantageous for many treatments, because this gives great water mobility on the web and the transport of the treatment agents between the two fleets and in particular the drawing up of the treatment agents from the entire fleet onto the fibers in the steaming step that generally follows the order.

A wet-on-wet application of a treatment liquid in two stages is known per se from DE-AS 10 78 527. However, the second order takes place in a gusset application unit, with which the high liquid occupancies of the material web required in the invention cannot be realized without the liquid running between the rollers and unevenness.

A preferred application example of the method according to the invention is the subject of claim 2.

It has been proven by extensive tests that the end processes when dyeing cotton fabric with direct or substantive dyes by the process according to the invention are brought down from a size of about 50 to 150 m of web length to a size of 3 to 5 m and the dye yield is reduced by up to 40% can be increased, so that the dye losses and also the environmental impact of heavy metals entering the wastewater can be reduced accordingly.

Further possible application examples of the method according to the invention are given in claims 3 and 4.

In the case of reactive dyes in particular, the losses have so far been so high that continuous processes have hardly been carried out.

It is particularly advisable here to keep the temperature of the two applied treatment liquors essentially the same, because this results in an optimal interaction of the same and with the material web.

However, the invention is in no way limited to dyeing treatments for textile webs. Rather, it can be used in all cases in which the liquor separation according to the invention offers procedural advantages, e.g. also when bleaching. There is also no restriction on the type of web. For example, also treated a paper or similar web, in particular dyed.

The object of the invention is achieved in its device aspect by the invention reproduced in claim 6, which can be implemented in detail in the manner represented in claims 7 to 11.

Gusset applicators of the type specified are known per se from FR-PS 13 81 081. However, the invention does not lie in the gusset application device as such, but in the combination of an impregnation device with squeezing with an impregnation device with very little liquor content, in which subsequently stripped, i.e. a relatively large fleet quantity is left evenly on the web.

In the drawing, an embodiment of the invention is shown in the form of a device designated 100 as a whole for dyeing a flat woven fabric made of cotton with direct dyes. The web 1 is first passed through a padder 10 forming the first application device, which includes a plunge pool 2, which at a width of the web 1 of 1.80 m 30 to 60 l of a salt liquor 3, through which the web is passed in the manner shown over a deflection roller 4, then passed vertically upwards and in the nip 5 between the nip rollers 6 and 7 to a moisture content of 70 to be squeezed off to 90% of the basis weight of the dry web 1.

The material web loaded with this moisture is then deflected vertically downward on a deflection roller 8 and thus passes into the gusset application device 20 which forms the second application device. The gusset application device 20 comprises mutually opposing walls 11, 12, which in the exemplary embodiment in FIG are essentially flat and slightly inclined to the web, ie approach her in the running direction. At the ends, the walls 11, 12 are connected to one another outside the edges of the web 1, so that an upright, funnel-like trough 9 is formed, which can be filled with a treatment liquid 13 up to a selectable low fill level.

At the lower end of the trough 9, oblong recesses 15, 16 are formed which extend across the width of the web and are open to the web 1 and in which inflatable pressure hoses 17, 18 are arranged. When inflated, the hoses 17, 18 lie on both sides with a gentle pressure which is very uniform over the width of the web and seal the trough 9 at the bottom. Outside the edges of the web 1, the hoses 17, 18 lie directly against one another and also seal in these areas. The material web is slidably pulled through the gap 19 between the hoses 17, 18. The 9th absorbed treatment liquor 13, which in the exemplary embodiment is a dye liquor with direct dyes, is stripped down to a total moisture content determined by the pressure in the tubes 17, 18. This total moisture content is in the range of approximately 100 to 200%, ie the same amount of treatment liquor is added to the gusset application device 20 as was already applied in the foulard 10.

The hoses 17, 18 can be coated on the mutually facing sides with a special sliding material. Thin sliding plates made of corrosion-resistant steel, which can withstand the stresses caused by the burr that can be found on the welded edges of the backs of carpet webs, have proven particularly useful.

The level in the trough 9 is kept very low. With a web width of 1.80 m and the corresponding width of the trough 9 there are, for example, 4 to 8 l of the treatment liquor 13 in the trough 9. This amount would only suffice for a few meters of web 1 and would be used up very quickly. For this reason, the treatment liquor 13 is constantly supplied fresh by a feed device 14 and is kept in the trough 9 at a constant, albeit low, level. A significant change in the concentration of the treatment liquor 13 by treatment agents carried along by the material web 1 cannot therefore occur. Except for very small processes of the order of magnitude from 3 to 5 m, the entire length of the web 1 is colored evenly.

The web 1 treated in this way now immediately moves into a damper 30 and then into a washing device 40 provided with several compartments.

TEST EXAMPLES 1. Dyeing with direct dyes

a) A flat fabric made of cotton with a weight per unit area of 200 g / m 2 was provided in accordance with the prior art in a foulard without the addition of salt with the following dyeing liquor and then steamed in the steamer for 2 minutes: 3.0 ml / l Wetting agent 2.0 ml / l Blocking aids 1.0 g / l Oxidizing agent 0.5 ml / l ventilator 7.7 g / l Direct blue I 2.3 g / l Direct blue II The fleet order was 85%, the working speed 30 m / min, the web width 1.8 m.

The result was a blue-colored web with end drains of the order of 100 m, which had to be used for other purposes.

b) An identical web was now dyed with the addition of salt on the device according to the invention in the same shade of blue.

First, the following salt liquor was applied to the foulard 10: 3.0 ml / l Wetting agent 3.0 ml / l Blocking aids 1.0 g / l Oxidizing agent 0.5 ml / l ventilator 30.0 g / l Table salt which was squeezed to a moisture content of 85%.

The material web 1 was then immediately fed into the gusset dyeing device 20 and provided there with a dyeing liquor which was composed as follows: 2.0 ml / l Wetting agent 4.2 g / l Direct blue I 1.2 g / l Direct blue II. The tubes 17, 18 were inflated with a pressure P = 0.5 bar, which resulted in an additional liquor application of 100%, so that the total moisture content of the web 1 after the gusset dyeing device was 185%. The web 1 loaded with it was steamed for 2 minutes and then washed in the washing device 40 in six compartments cold with overflow. The result was the same shade of blue as in case a), but the flow was only 5 m and, instead of as in case a), with 7, 7 plus 2, 3 = 10 g / l of dye with 4, 2 plus 1, 2 = 5.4 g / l dye could be worked. The addition of salt promoted the absorption of the dye in such a way that a much larger proportion of the dye actually applied to the fibers or, conversely, to achieve the same shade depth, a 37% lower use of dye could be used. The dye losses and the pollutants, in particular heavy metal ions, which are introduced into the wastewater by the otherwise washed-out losses are correspondingly reduced. So it will be both in this Area as well as by shortening the processes.

2. Staining with sulfur dyes

a) According to the prior art, a flat fabric made of cotton with a basis weight of 250 g / m² in a width of 1.8 m was provided at a speed of 45 m / min on a foulard with the following dyeing liquor: 3.0 ml / l Wetting agent 2.0 g / l Complexing agent 14.6 g / l Sulfur black 9.0 g / l Sulfur brown 1.8 g / l Sulfur red 20.0 g / l glucose 35.0 ml / l NaOH 29% 3.0 ml / l Sodium borate 3.0 ml / l Wetting agent 0.5 ml / l ventilator and squeezed to a moisture content of 85%. After steaming and washing there was a gray color with an end run of 100 m.

b) An identical material web 1 was provided in the foulard 10 with the following salt liquor: 3.0 ml / l Wetting agent 30.0 g / l Table salt 0.5 ml / l ventilator and squeezed to a moisture content of 85%. The web 1 was then introduced into a gusset application device 20 and provided with the following dyeing liquor there: 2.0 g / l Complexing agent 11.1 g / l Sulfur black 6.8 g / l Sulfur brown 1.4 g / l Sulfur red 20.0 g / l glucose 35.0 ml / l NaOH 29% 3.0 ml / l Sodium borate 3.0 ml / l Wetting agent 0.4 ml / l ventilator The fleet order was 100%, so that there was again a total moisture content of the web 1 of 185%, with which the web 1 entered the damper 30. It was then washed in washer 40 in six compartments as follows: 1. 50 ° C Overflow 2nd 70 ° C Overflow 3rd 95 ° C oxidize 15 ml / l textile auxiliaries 4th 95 ° C oxidize 1 g / l soda 5. 50 ° C Overflow 6. cold Overflow

The result was a gray color with a run of about 5 m. The amount of sulfur black consumed of 25.4 g / l on the one hand and 19.3 g / l on the other hand results in a dye saving of 13% with the same dyeing result

3. Bleach

A cotton fabric web with a basis weight of 150 g / m² was provided with the following impregnation on a foulard: 6.0 g / l NaOH solid as an alkali 2.0 g / l alkali-resistant wetting agent 6.0 g / l organic stabilizer 1.0 g / l Complexing agent and squeezed to a moisture content of 80%. The material web 1 was then introduced into a gusset application device 20 and there was additionally provided with an order of 80% of the following bleaching liquor: 30.0 g / l Na peroxide 35%

Claims (11)

1. Continuous process for treating a textile web under wet-on-wet application of two interacting treatment liquors, in which a first treatment liquor is first applied and squeezed and then a second treatment liquor is applied to the still wet web so that the web is always is only in contact with a small, continuously used and freshly replenished fleet supply, whereupon the fabric web is immediately partially dehumidified, characterized in that the fabric web is squeezed to a moisture content of 60 to 120% after application of the first and after the order of the second treatment liquor is partially dehumidified in such a way that it is stripped to a total moisture content of 100 to 200% while passing through a gap with at least one elastic border on the web. 2. The method according to claim 1,
characterized,
that a salt liquor and a dye liquor are applied with direct dyes,
that a first of these liquors is first applied and squeezed to a moisture content of 70 to 90%,
that the second of these fleets is then applied
and that the web is then stripped to a total moisture content of 130 to 160%. 3. The method according to claim 1,
characterized,
that a salt liquor and a dye liquor with sulfur dyes are applied,
that a first of these liquors is first applied and squeezed to a moisture content of 70 to 90%,
that the second of these fleets is then applied
and that the web is then stripped to a total moisture content of 160 to 200%. 4. The method according to claim 1,
characterized,
that an alkali liquor may be applied with salt and a dye liquor with reactive dyes,
that a first of these liquors is first applied and squeezed to a moisture content of 70 to 100%,
that the second of these fleets is then applied
and that the web is then stripped to a total moisture content of 160 to 200%. 5. The method according to any one of claims 1 to 4, characterized in that the temperature of the two applied treatment liquors is the same. 6. Device for the continuous treatment of a textile web, in which two application devices for treatment liquors are arranged one behind the other in the direction of travel of the web and the web runs in with the moisture of the first application device into the second application device, in particular for carrying out a method according to one of claims 1 to 5, wherein the first application device comprises an impregnation device for the web with a downstream roller crusher and the second application device comprises an impregnation device for the web, in which the web is in contact with both sides only with a very small, constantly metered addition of fleet stock, in accordance with consumption a gap extending directly across the width of the goods is immediately downstream, characterized in that the gap (19) is formed in a stripping device (17, 18) and at least on one side of the material web in a crosswise across the material web (1) zone is bounded by a flexible wall that is inflatable by a fluid pressure medium against the material web (1) and seals against it. 7. Device according to claim 6, characterized in that the first application device is a foulard (10). 8. Device according to claim 6 or 7, characterized in that the second application device is a gusset application device (20) with mutually on both sides of the web (1) opposite walls (11, 12), which at the ends laterally outside the web (1) are connected and form an upright, transversely across the width of the web, up to a selectable fill level with a treatment liquor (13) fillable trough (19) through which the web (1) can be passed vertically and at the lower end of the gap (19). 9. Device according to claim 8, characterized in that the gap (19) by two mutually parallel on both sides of the web (1) opposite, flexible, inflatable against the web and sealingly abutting walls is limited. 10. The device according to claim 9, characterized in that the walls are formed by two inflatable tubes (17, 18). 11. Device according to one of claims 8 to 10, characterized in that the trough (9) is filled with at most an amount of treatment liquor (13) which is sufficient for the treatment of 30 m web (1).

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