EP0799924A2 - Method for continuous dyeing of warp yarns and device for carrying out the method - Google Patents

Abstract

For the continuous dyeing of warp yarns, the band of warps is passed through a hermetically sealed dye reactor (1), structured to give the best technological results for each group of dyestuffs. After initial immersion in fresh dye for impregnation, the yarns pass through an intermediate mangle (3a) within the reactor (1). The fixing dwell time is given through the passage round guide and deflection rollers (5a-5g), with oxygen excluded and without further immersion in the dye, with a variable dwell time to give the required deg. of colouration according to the set technological conditions. Also claimed is an appts. with a dye reactor (1) as a vessel closed at the top. The bottom of the vessel, forming the base, has containers (2a-2c) for the dye baths. Water locks are over the side walls from the outer dye bath containers (2a,2c) for each formed by guide and deflection rollers (4a-4c), sealed against the ambient environment, to carry the band of warps in and out. An intermediate mangle (3a), within the reactor (1), has a variable pressure setting down to zero pressure, working with warp guide and deflection rollers (5a-5g). A hydraulic pipe system, below the reactor (1), feeds the baths with dyestuffs.

Description

The invention relates to a process for the continuous dyeing of warp yarn, in particular cotton warp yarn with indigo or other dye groups which, after impregnation and squeezing, require oxidation or heat treatment for development and fixing.

Continuous warp yarn dyeing machines for dyeing with indigo for blue denim are known, which consist of connected dye containers with a squeeze mechanism one behind the other or dyeing foulards with a relatively large bath volume. These dye containers or foulards are also used for dyeing with sulfur or vat dyes for black and color denim. In order to solve ink run problems and to achieve a better dye yield, it is known to integrate additional units in warp yarn dyeing machines, consisting of a dyeing pad with a saving trough and a subsequent damper, units that cannot be used for the main production of indigo dyeing.

The known dyeing containers with squeezing mechanism or dyeing foulard consist of simple roller skids, in which the chain to be colored is impregnated by being guided and deflected over several cylinders or rollers and / or deflecting rollers, which are located under the fleet, and then squeezed off. The route of the chain under the fleet and thus the dwell time in the ink liquor is determined by the number of sub-liquor rollers and deflection rollers and their distance from one another.

Since the warp speed is specified for dyeing with indigo and is practically unchanged, the immersion time and the liquor volume are constant here and are therefore only dependent on the design of the dye container.

Due to the growing demand for indigo blue denim fabrics with different wash fastnesses and different shades, for indigo colors from light blue to super blue as well as the increasing market shares for black and color denim, greater flexibility is required.

Different depths of nuance, for example in conventional indigo dyeing systems with lighter shades, require the use of a few dye containers. In the case of dark shades, several dye containers connected in series are required. In the case of a dark shade, six dye containers, each with up to 2500 l of dye liquor, are used. This means that conventional indigo dyeing systems have to be converted to produce different depths of shade. Depending on the desired color shade, more dye containers have to be inserted or removed, and liquors have to be pumped in or out. The paint fleet, which is temporarily not required, has several thousand liters can make out, must be drained or temporarily stored.

In the known loop dye system, only one dye bath is required, through which the warp thread sheet is guided several times one above the other, four or five times for dark indigo nuances.

Shades other than indigo blue are colored with other dye groups, usually sulfur or vat dyes. These and also the other cotton dye groups, such as reactive and direct dyes, have different affinities for cotton, mostly higher than indigo. The affinities are also largely influenced by the dyeing temperature, which can be far apart for the different dye groups. For example, the affinity and the dye yield of indigo increase with falling temperature, whereas it usually increases with increasing temperature with other dye groups.

A greater affinity and dye yield would be achievable by cooling the indigo dye baths in conventional dyeing machines, but it is economically disadvantageous due to the large number of dye containers and the large amount of dye liquor.

Another problem that occurs with conventional dyeing machines is that the dye is pulled out of the dye bath by the affinity.

The result is that the beginning of the lot is colored darker than the end of the warp yarn group, so that the so-called head-tail flow occurs. This dreaded appearance, which can show up over several thousand meters of the chain to be colored, occurs particularly in large systems with large dye bath volumes, which lead to long color sequences.

It is therefore an object of the invention to eliminate the disadvantages of conventional processes for the continuous dyeing of warp yarn, in particular cotton warp yarn with indigo or other dye groups, which, after impregnation and squeezing, require oxidation or heat treatment for fixation. In particular, the required amount of liquor should be significantly reduced, and economically favorable conditions for cooling or heating the paint liquor should be made possible. The residence time of the warp yarn coulter in the dyeing system should also be variable, using simple constructional means, and the fixing temperature should be selectable from below room temperature to over 100 ° C.

The object of the invention is to provide a process for the continuous dyeing of warp yarn, in particular cotton warp yarn with indigo or other dye groups, which enables a high degree of variability in the dyeing of warp yarns with different shades of color, but also with different dye groups, and a device which can optionally be used for Use of Indigo, sulfur or vat dye colors under the optimal conditions.

According to the invention, this object is achieved in that a warp yarn group is passed through an airtight, closed dyeing reactor which can itself be adapted to the optimum technological conditions for the respective dye groups. For this purpose, after an initial immersion, the warp yarn coulter is impregnated in fresh dye liquor and then squeezed off in an intermediate crushing unit located in the reactor. The dwell fixation is then carried out via guide and deflection rollers with the exclusion of oxygen without or optionally with repeated dipping in fresh dye liquor, the dwell time of the warp threads in the dyeing reactor being variable, according to the desired shade and the technological requirements placed on the respective dye group.

The dyeing reactor according to the invention is a container which is closed at the top and has openings at its lower end for the entry and exit of the warp yarn coulter. Containers for the dye liquor, into which the lower reactor opening is immersed, are arranged below the dyeing reactor. These containers each form a water castle with guide and deflection rollers, which seal the dyeing reactor from the environment and through which the warp yarn sheet is fed in and out. In addition, another can be in the inlet trough Squeezing mechanism can be arranged, which squeezes out air that is still contained in the incoming warp yarn coulter. These containers are equipped with raised floors, through which the indigo dye liquor can be cooled, but other dye baths, for example sulfur dye, can be heated. An intermediate crushing unit is arranged in the dyeing reactor, the squeezing pressure of which can be set to variable or unpressurized. Instead of the intermediate crushing unit or in addition to this, pairs of rollers can be used, which strip off the excess ink liquor when the squeezing unit is open and thus prevent the ink liquor from dripping down. The pairs of rollers are adjustable and arranged so that the warp yarn share must make a more or less pronounced S curve or a Z curve. The dwell time of the warp yarn coulter can be shortened or lengthened, depending on the technological requirements, by means of guide and deflection rollers which are arranged in the interior of the dyeing reactor and can be displaced vertically in the interior.

A hydraulic pipe system for charging the reactor with liquors is arranged below the dyeing reactor. This circulation system, consisting of supply pipes with pumps arranged therein and a plurality of valves, serves to circulate the impregnation or paint liquor and, if necessary, to meter in a more concentrated additive.

Further tasks, features, details and advantages of the method according to the invention and the device according to the invention for carrying it out result from the following description of exemplary embodiments with reference to the attached drawing.

Fig. 1

einen Färbereaktor im Schnitt in Seitenansicht,

Fig. 2

den Färbereaktor gemäß Fig. 1 mit verkürztem Kettfadeneinzug,

Fig. 3

den Färbereaktor nach Fig. 1 beim Färben mit kleinster Flottenmenge,

Fig. 4

den Färbereaktor nach Fig. 1 beim Färben mit größter Flottenmenge.

Show it:

Fig. 1

a side view of a dyeing reactor,

Fig. 2

1 with shortened warp threading,

Fig. 3

1 when dyeing with the smallest amount of liquor,

Fig. 4

the dyeing reactor of FIG. 1 when dyeing with the largest amount of liquor.

The dyeing reactor 1 shown by way of example in FIG. 1 is a container closed at the top. On its lower side it has three dye containers 2a, 2b, 2c, which are filled with liquor. The containers 2a and 2c are also water locks, ie the lower part of the side walls of the dyeing reactor 1 protrudes into the dyeing reactor 1 after filling the containers 2a and 2c, so that the entry of ambient air, in particular atmospheric oxygen, into the dyeing reactor 1 is prevented. In addition, a further crushing mechanism 3c can be arranged in the inlet trough 2a, which air is still contained in the entering warp yarn coulter. In addition, the containers 2a and 2b contain double bottoms 7a and 7b, through which the dye liquors can be cooled (in the case of indigo) or heated (for example in the case of sulfur dye).

In the dyeing reactor 1 there is an intermediate squeezing unit 3a which can squeeze the warp yarn to such an extent that no "liquor noses" arise as the warp threads continue to run. With this intermediate squeezer 3a, the pinch pressure on the warp yarn coulter can be varied to zero pressure by means of adjustable pressure rollers.

Instead of the intermediate squeezing unit 3a or in addition to this, pairs of rollers A ₁ , A ₂ can be used, which strip off the excess ink liquor when the squeezing unit is open and thus prevent the ink liquor from dripping down. The roller pairs A ₁ and A ₂ are adjustable and arranged so that the warp yarn share must make a more or less pronounced S curve or a Z curve.

Guide and deflecting rollers 4a, 4b, 4c are located in the dyeing reactor 1 directly above the containers 2a and 2c. These are so-called sub-fleet rollers of the water castles. The warp yarn sheet is guided through the dyeing reactor 1 by further guide and deflecting rollers 5a to 5g provided in the dyeing reactor 1. These guide and deflecting rollers 5a to 5g are so-called ribbed rollers. The ribs 11 of these rollers prevent possible crossing of the threads. The finned rollers remain free of fibers and dirt, which prevents thread breaks. Furthermore, these guide and deflection rollers 5a, 5b, 5c and 5g are vertically adjustable in the reactor, whereby the warp thread length can be varied. In the example according to FIG. 1, the draw-in length K1 is 16 m. The shortened indentation K2 is shown in the example according to FIG. 2, it is 7 m long.

The reactor ceiling 8 is heatable and sloping so that dropping is avoided. Furthermore, the dyeing reactor 1 can be heated with steam through an annular steam tube 9.

In the case of heat fixation with steam, e.g. with sulfur dyes, excess steam is discharged through a chimney 10. The chimney 10 has overpressure control, i.e. it opens at a certain predetermined vapor pressure.

3 and 4, the hydraulic pipe system and the reactor feed with liquors are shown.

The ink liquor is fed through an inlet 11a. The uniformity of the feed liquor, which is higher in concentration than the impregnation liquor, is ensured by the fact that it flows evenly over the entire width of the reactor into the first paint container 2a via a horizontal weir. The volume the color liquor in this first container 2a is, for example, 150 l.

The process of the dye liquor can optionally take place via an overflow 11b or an overflow 11c, depending on which dye containers each contain liquor. Here, too, the weir is ensured across the entire width of the reactor by horizontal weirs.

The overflow of the squeezed and depleted liquor of a main squeeze unit 3b located outside the dyeing reactor 1 takes place via an outlet 11d.

The circulation of the impregnation or dye liquor, which is very important for uniform coloring, is ensured in the case of the choice of the small bath volume of 150 l via a circulation line system 12a and 12b with a circulation pump 14 which has a variable pumping capacity between 600 and 6,000 l / h . If the impregnation is selected in the two dyeing tanks 2a and 2b, with a liquor volume of 150 l in the first tank and 80 l in the second tank, the liquor circulation is also carried out via a second circulation system 12a and 12c by means of the circulation pump 14.

The selection of the small or large circulation of the paint liquors is controlled via valves 13a, 13b and 13c. The valve 13f on the drain pipe prevents accumulation the fleet in the event that an empty container is chosen.

The depleted liquor of the main squeeze unit 3b is fed into the dyeing reactor 1 via a further circulation system 12d and can be regulated via a valve 13d.

The continuously necessary concentration of the dye liquor with the amount of dye and chemicals required, which is carried along by the emerging warp threads, is carried out by metering in a more highly concentrated batch via an inlet 16 with a metering pump 17, which can be regulated via the valve 13e. This admixture of the additive to the two dye liquors in circulation, the circulation liquor and the squeezed-out depleted liquor of the main crushing unit 3b, takes place via a mixing tank 15 with a liquor volume of 30 l, including the pipelines.

The total volume of the dye liquor involved in the dyeing process is thus in a preferred example when only the first dye container 2a is used $$\text{150 + 60 + 30 = 240 l.}$$

When loading both dyeing tanks 2a and 2b, the total volume is $$\text{150 + 80 + 60 + 30 = 320 l.}$$

Of course, other total volumes of color liquor to be used are also possible. For example, a reduction through the use of displacement bodies in the dyeing tanks or an enlargement can be achieved by increasing the inflows and outflows and increasing the liquor level.

Two preferred dyeing processes are described in more detail below using exemplary embodiments:

Example 1:

A dye liquor with a total volume of 320 l is used for indigo dyeing in a standard navy blue shade. An indigo dip bath with 3 g / l indigo and the necessary amount of sodium hydroxide solution and hydrosulfite are used as reducing agents in order to reduce the dye.

After filling the two dyeing tanks 2a and 2b and the tank 2c of the main squeeze unit 3b, the latter in a 1: 1 dilution, the dye liquor is circulated via the circulation system 12c, 12a and the pump 14.

The valve position is as follows: valves 13a, 13c, 13d and 13e are open, the valve 13b is closed.

Thanks to the large chain feed (16 m), the dyeing speed can be up to 50 m / min and must be adjusted accordingly.

In this example, the impregnation liquor is expediently cooled to 15 ° C., which significantly increases the affinity of indigo for the cotton yarn. In addition, environmental temperature changes are kept away from the inside of the dyeing reactor.

The preparation of the prepared make-up of 80 g / l indigo with the required chemicals is proportional to the warp thread weight. The control of the dosing is carried out by a PC, which measures the incoming warp thread transfer, converts it to the weight per unit of time (e.g. 18 kg / min) and then doses the batch quantity proportionally. In this example, 4.5 l / min of make-up solution is metered in for a 2% staining at a make-up concentration of 80 g / l indigo.

If you choose the longest feed of 16 m, the dye yield will be the highest possible and the fastness to washing as well.

If you choose a smaller feeder, the wash fastness will be lower, which can certainly be required of the STONE washer.

Example 2:

In the case of sulfur dyeing for black denim or color denim, the procedure is basically the same as that described in Example 1, with the exception that only the first dyeing tank 2a is used and the total volume is 150 + 60 + 30 = 240 l is reduced.

Furthermore, the dye liquor is heated to at least 90 ° C and the interior of the reactor by steam to 100 ° - 102 ° C.

The warp threading is expediently 16 m, since the long residence time ensures the best dye yield.

Claims (21)

A process for the continuous dyeing of warp yarn, in particular cotton warp yarn, with indigo or with other dye groups, mainly sulfur and vat dyes, in which a parallel group of unbundled warp threads is impregnated by passing it through one or more dye containers filled with a dye liquor via roller skids or a dyeing pad as well as to extend the dwell time over several cylinders or rollers and / or deflection rollers that are in the paint liquor, then squeezed out via a squeeze mechanism, rinsed, finished and wound onto a warp beam,
characterized in that the warp yarn sheet is guided by an airtightly closed dyeing reactor (1) which can be adapted to the optimal technological conditions for the respective dye groups, so that the warp yarn sheet is impregnated in fresh dye liquor after an initial immersion, then in a soak Intermediate crushing unit (3a) located in the dyeing reactor (1) is squeezed off and then the dwell in fixation takes place with the exclusion of oxygen via guide and deflecting rollers (5a to 5g) without repeated dipping in fresh dye liquor, the dwell time of the warp threads in the dyeing reactor (1) being variable, accordingly the desired color shade and the technological requirements placed on the respective dye group can be adapted. A method according to claim 1, characterized in that after entering the dyeing reactor (1) the warp yarn sheet is immersed in an indigo dye liquor with a liquor content of less than 300 l and with a concentration of 3 g / l, after being squeezed in the intermediate crushing unit (3a) the concentration in the warp is reduced to about half, so that in the subsequent dwell time of the warp yarn in the reactor, the high concentration of 3 g / l still present can be drawn onto the cotton threads. A method according to claim 1, characterized in that the cooling of the dye liquor and the dwell time of the warp yarn in the dyeing reactor (1) can be adjusted during indigo dyeing in such a way that a maximum dye yield is achieved and the number of dye tanks or the dip-oxidation processes to be repeated is minimized becomes. A method according to claim 1, characterized in that the bath concentration in the outlet container (2c) is set so low that there is only little unfixed dye to be washed out in the subsequent rinsing bath on the chain after squeezing. A method according to claim 1, characterized in that to avoid oxidation of the dye in the hermetically sealed dye reactor (1) an inert gas, for example nitrogen, is introduced. A method according to claim 1, characterized in that, in order to avoid oxidation of the dye in the hermetically sealed dyeing reactor (1), the air in the incoming warp yarn coulter by a squeeze mechanism (3c) located at the entrance to the dyeing reactor (1), under liquor, is squeezed out. A method according to claim 1, characterized in that the indigo dye liquors located in the dyeing tanks (2a, 2b, 2c) can be cooled to increase the affinity. A method according to claim 1, characterized in that the sulfur dyes or vat dyes in the dyeing tanks (2a, 2b, 2c) can be heated and the reactor interior can be heated by means of steam. Method according to claim 1, characterized in that the squeezing of the warp yarn threads in the intermediate squeezing unit (3a) can be variably adjusted or disengaged to influence the dyeing and the fastness to washing. A method according to claim 1, characterized in that the uniformity of the dye liquor supply, which is above the concentration of the impregnation liquor, to the dyeing reactor (1) via the inlet (11a) is ensured with a weir, while the discharge of the dye liquor optionally via the outlet weir (11b ) or via the outlet weir (11c), depending on the choice of the dye liquor container or containers containing the impregnation liquors, and that the squeezed and depleted ink liquor overflows via the main crushing unit (3b) located outside the dyeing reactor (1) and the weir ( 11d) takes place. Method according to Claims 1 and 10, characterized in that the circulation of the impregnation or paint liquor is carried out via a circulation system (12a, 12b, 12c) with the circulation pump (14) in that a selection is made via valves (13a, 13b, 13c) can be determined for a smaller or a larger fleet volume and the depleted ink fleet of the main crushing unit (3b) is fed in via the pipe system (12d) with a controllable valve (13d). A method according to claim 1, 10 and 11, characterized in that the continuously necessary concentration of the dye liquor with the amount of dye and chemicals required in each case, that of the dye liquor through the dyeing of the warp threads is withdrawn, by metering in a more highly concentrated additive via an inlet (16) with a metering pump (17), which is regulated via a valve (13e). Apparatus for carrying out the method according to claims 1 to 12, characterized in that the dyeing reactor (1) is a container closed at the top, at the lower end of which, forming the reactor base, containers (2a, 2b, 2c) for the dye liquor are arranged, wherein the containers (2a and 2c) protruding from the side walls each form a water lock with guide and deflecting rollers (4a, 4b, 4c), which are sealing against the environment for the feeding and removal of the warp yarn coulter and that in the dyeing reactor (1) Intermediate crushing unit (3a), the squeezing pressure of which can be adjusted variably to unpressurized, as well as guide and deflecting rollers (5a to 5g) and below the dyeing reactor (1) a hydraulic pipe system for charging the reactor with liquors is arranged. Apparatus according to claim 13, characterized in that the guide and deflection rollers (5a to 5g) are arranged so as to be vertically displaceable in the dyeing reactor (1) in order to lengthen or shorten the warp thread group. Device according to claim 13, characterized in that the guiding and deflecting rollers (5a to 5g) are designed as fin rollers. Apparatus according to claim 13, characterized in that pairs of rollers (A ₁ , A ₂ ) which can be adjusted for stripping off excess liquor, preferably made of teflon-coated rods, are arranged in the dyeing reactor (1). Device according to claim 13, characterized in that the bottoms (7a, 7b) of the containers (2a, 2b) are designed to be heatable and coolable for the dye liquor. Apparatus according to claim 13, characterized in that the upper end (8) of the dyeing reactor (1) is designed to slope downwards and can be heated, and that an annular steam tube (9) is arranged for heating the interior of the dyeing reactor (1). Apparatus according to claim 13, characterized in that the dyeing reactor (1) is equipped with a chimney (10) with overpressure control. Apparatus according to claim 13, characterized in that the hydraulic pipe system for feeding the reactor and for circulating the impregnating or dye liquor from the feed pipes (12a to 12d) with a pump (14) arranged therein and the valves (13a to 13d) and a metering pump (17) is arranged in an inlet (16) with valve (13e) for metering in a more highly concentrated batch. Apparatus according to claim 13, characterized in that horizontal weirs are arranged in the inlet (11a) and the outlets (11b, 11c) to ensure uniformity of the dye liquor over the entire reactor width.

Images