EP0179353B1 - Method for dyeing on a jigger - Google Patents

Abstract

1. A method of dyeing textile fibres on a jigger, wherein the required amount of dyestuff is divided into two or more portions, characterised in that the first portion is added to the dye bath while the jigger is stationary and in the meantime the dye bath is heated to the temperature range for optimum dyestuff absorption, and in that after actuation of the jigger the other portion or portions of dyestuff is (are) introduced into the dye bath linearly as a function of the amount of fabric which passes through the dye bath, wherein the number of passes of the amount of fabric through the dye bath corresponds to the number of portions of dyestuff and the dye bath has a temperature within the range for optimum dyestuff absorption.

Description

The present invention relates to a method for dyeing textile fibers on a jigger, the necessary amount of dye being divided into two or more subsets. As is known, the jigger is a machine of the type in which a fabric web, also called a material web, is alternately unwound from the one of two rolls and wound thereon and kept immersed in a dye bath between the two rolls during the passage.

The web length immersed in the dye bath is usually of the order of 2 m, and since the speed of the web is of the order of 80-200 m / min. is, a certain point of the web will move during a passage in the dye bath in a period of the order of 1/3 - 3/4 sec. stop.

It is probably experimental and generally accepted that only extremely small amounts of dye are substantively absorbed onto the fibers of the goods during their very short stay in the dye bath during the passage. The dye is transferred from the dye bath to the web by exchanging a certain volume of liquid in the web with a corresponding volume of liquid from the dye bath, and the actual absorption of the dye in the fiber material occurs through the (much longer) period when the web winds up on the rolls if the conditions for dye absorption such. B. optimal temperature and the like are given.

If the jigger is operated under conditions where the conditions for dye absorption are optimal, there is a great risk of uneven color distribution along the web, because the dye concentration in the amount of liquid absorbed by the web during the passage due to the dilution effect of one Side of the web varies exponentially to the other.

• M_v = das Trocken gewicht der Ware
• f = die gesamte Badmengs das rockengewicht der Ware f₁ = die Flüssigkeitsmenge in aufgewickelter Warenbahn
• f₁ das Troc ce-1 n ämc der are _ die Badmenge im Farbbottich f-f₁ das Trockengewicht der Ware
• = die Flüssigkeitsmenge in aufgewickelter Warenbahn F ^f1f-f₁ die Badmenge im Farbbottich
• K_b = die augenblickliche Farbstoffkonzentration im Farbbad im Bottich
• V_v = Flüssigkeitsmenge in der aufgewickelten Warenbahn = f₁ . M_w
• V_b = das Badvolumen Badmenge im Farbbottich = (f - f₁) . M_v
• 
• p = Der Austauschgrad, d. h. der Teil der in der Ware enthaltenen Flüssigkeit, der bei der Passage ausgetauscht wird.
• u = Der Teil der ganzen Warenlänge, der eben durch das Bad passiert hat, so daß u = 0 am Anfang der Passage und u = 1 am Ende der Passage ist.

If the entire amount of dye is added to the bath from the start during the first passage on the jigger, the dye concentration in the web K _v in relation to the initial concentration K _{bo of} the bath during the passage can be calculated as follows:

• M _v = the dry weight of the goods
• f = the total amount of bad the rock weight of the goods f ₁ = the amount of liquid in the wound web
• f ₁ the Troc ce-1 n ämc der are _ the amount of bath in the ink tub ff ₁ the dry weight of the goods
• = the amount of liquid in the wound web F ^f1 ff ₁ the amount of bath in the ink tub
• K _b = the current dye concentration in the dye bath in the vat
• V _v = amount of liquid in the wound web = f ₁ . M _w
• V _b = the bath volume of the bath in the color vat = (f - f ₁ ). M _v
• 
• p = The degree of exchange, ie the part of the liquid contained in the goods that is exchanged during the passage.
• u = The part of the total length of goods that has just passed through the bath, so that u = 0 at the beginning of the passage and u = 1 at the end of the passage.

. du

The dye exits the bath:

. you

with the boundary condition K _h = K _ho for u = 0 the solution of this differential equation is:

or for the concentration in the goods, where K _u = Kb - P

The following passage will compensate for the uneven concentration distribution from the first passage, for example due to the opposite effect of the new exponential dye uptake, but a full adjustment cannot be achieved.

A method for dyeing on a jigger is known from German Patent No. 106,342, an attempt being made to eliminate the uneven dyeing by gradually adding the entire dye liquor to the jigger tub during the first passage, but using a small amount of the liquor to cover the bottom rollers may be added in advance.

This process also does not guarantee an even color distribution, since the bath concentration decreases in the course of the passage due to the increasing fabric speed on the old-fashioned jigger described in the German patent. The process is also impractical because it requires a container of the same size as the jigger tub to store the entire liquor.

• 1. Die gesamte Farbstoffmenge in mehrere Teilmengen aufgeteilt wird, am meisten zwei, und die Zuführen der Farbstoffmenge mit einer Teilmenge vor dem Anfang jeder neuen Passage geschieht.
• 2. Das Färben fängt mit einer so niedrigen Temperatur an, daß die Farbstoffabsorption in der aufgewickelten Warenbahn gering ist. Im Laufe einer Reihe von Passagen wird das Bad dann stufenweise zur optimalen Farbtemperatur beheizt.
• 3. Man stellt die Geschwindigkeit der Farbstoffabsorption chemisch ein, beispielsweise durch ein sukzessives Erhöhen der Elektrolytkonzentration im Bad (Zusatz von Salz).

In order to avoid uneven dyeing of the material web, one has to have a practice over time developed what:

• 1. The total amount of dye is divided into several subsets, mostly two, and the supply of the dye amount with one subset occurs before the start of each new passage.
• 2. The dyeing begins at such a low temperature that the dye absorption in the wound web is low. The bath is then gradually heated to the optimum color temperature over a series of passages.
• 3. The rate of dye absorption is adjusted chemically, for example by successively increasing the electrolyte concentration in the bath (addition of salt).

• 1.1. Die Hälfte oder zwei Drittel der gesamten Farbstoffmenge wird dem Bad vor der ersten Passage bei einer Temperatur von 50°C zugesetzt, wo die Farbstoffabsorption nicht zu beachten werden braucht.
• 1.2. Der Rest der Farbstoffmenge wird vor Anfang der zweiten Passage, noch bei 50° C, zugesetzt.
• 2.1. Vor Anfang der 3. Passage wird auf 60° C beheizt
• 2.2. Vor Anfang der 4. Passage wird auf 70° C beheizt
• 2.3. Vor Anfang der 5. Passage wird auf 80° C beheizet
• 2.4. Vor Anfang der 6. Passage wird auf 90° C beheizet
• 2.5. Vor Anfang der 7. Passage wird auf 100°C beheizt
• 2.6. Hiernach läuft eine gewisse Anzahl Passagen bei 100°C, bis Gleichgewicht zwischen der Farbstoffkonzentration in der Flüssigkeitsphase und der Farbstoffkonzentration im Fasermaterial sozusagen erreicht worden ist.

A general procedure today is to combine the above measures 1 and 2 in the following manner, for example:

• 1.1. Half or two thirds of the total amount of dye is added to the bath before the first passage at a temperature of 50 ° C, where the dye absorption need not be taken into account.
• 1.2. The rest of the amount of dye is added before the beginning of the second passage, still at 50 ° C.
• 2.1. Before the 3rd passage begins, the temperature is raised to 60 ° C
• 2.2. Before the 4th passage begins, the temperature is raised to 70 ° C
• 2.3. Before the 5th passage begins, the temperature is raised to 80 ° C
• 2.4. Before the 6th passage begins, the temperature is raised to 90 ° C
• 2.5. Before the 7th passage begins, the temperature is raised to 100 ° C
• 2.6. After this, a certain number of passages run at 100 ° C. until a balance between the dye concentration in the liquid phase and the dye concentration in the fiber material has been reached, so to speak.

Today's normal practice is still to combine the three measures above to avoid uneven dyeing of the web, but the example also shows that this practice requires a lot of time and labor.

The disadvantages mentioned apply to the jigger as a machine type, regardless of whether it is a machine that cannot be pressurized and therefore can only work at a bath temperature of 100 ° C or whether it is an HT jigger (high-temperature jigger), which is pressurized and can therefore work at higher temperatures.

However, the purchase of an HT jigger is considerably more expensive than the 100 ° C machine, and it is therefore crucial for profitability that the process time can be reduced to a minimum.

Of the fiber types that require color temperatures above 100 ° C, the polyester fiber is the most important, and the optimal color temperature of this fiber is 115 - 135 ° C, depending on whether you are working with low-molecular or high-molecular dyes. At these temperatures, dye absorption cannot be controlled by chemical means, and it is therefore common to control dye absorption by gradually increasing the temperature from a range where the absorption is zero, so to speak, to the optimal range. Since the limits of this area are very narrow, it turned out to be necessary to raise the temperature in very small steps. The process is also difficult in that it may be necessary to use different dye groups for the same dyeing, so that a critical temperature range has to be passed for each dye group. Since each jigger passage can take 30-60 minutes, it should be understood that this procedure takes a long time.

The present invention provides a method for dyeing on a jigger which ensures uniform dyeing of the web and which does not have the disadvantages of the known methods, i. H. poor economic exploitation of the jigger due to the time-consuming and labor-intensive gradual and slow heating of the dye bath. The method according to the invention is characterized in that the first subset is added to the dyebath while the jigger is at a standstill, during which the dyebath is heated to the temperature range for optimum dye absorption, so that after the jigger is actuated, the remaining subset or remaining subsets of dye ins Dye bath is entered linearly as a function of the amount of fabric that passes through the dye bath, the number of passages of the amount of fabric through the dye bath corresponding to the number of dye subsets and the dye bath having a temperature within the range for optimal dye absorption.

It has been shown in practice that this achieves uniform coloring and calculation, cf. below, confirms this result.

• 1. Der Farbstoff wird in die Warenbahn während der Passage durch das Bad infolge eines Austausches einer bestimmten Flüssigkeitsmenge zwischen der Flüssigkeitsphase der Warenbahn und dem Farbbad aufgenommen. Diese Voraussetzung gilt auch bei der ersten Passage, da die Warenbahn naß ist, beispielsweise durch ein vorhergehendes Waschen, wenn sie in den Jigger eingesetzt wird.
• 2. Der Farbstoff wird von der Flüssigkeitsphase der Warenbahn von den Fasern absorbiert, während die Ware im aufgewickelten Zustand ist, so daß die Flüssigkeitsphase der Warenbahn keinen Farbstoff enthält, wenn die Ware das Bad das nächste Mal passiert.

There are two prerequisites for the calculation:

• 1. The dye is taken up into the web during passage through the bath due to an exchange of a certain amount of liquid between the liquid phase of the web and the dye bath. This requirement also applies to the first passage, since the web is wet, for example by washing it beforehand when it is inserted into the jigger.
• 2. The dye is absorbed by the fibers from the liquid phase of the fabric while the fabric is in the wound state so that the liquid phase of the fabric contains no dye the next time the fabric passes the bath.

The second requirement is only sufficiently correct as long as the color process is far from the eventual equilibrium state, but it is precisely in this initial phase that the risk of uneven color absorption is greatest. As one approaches the eventual equilibrium state, the rate of absorption slows down and the risk of uneven ink absorption is reduced.

In the method according to the invention the total amount of dye is M. A subset thereof M ₁ is added before the start of the process and the dye bath thus contains the amount of dye

The web takes a dye menu during a passaae

and this amount is replaced by dosing one or more aliquots during the subsequent passages.

Dies gibt für

• n = 1 0,52
• n = 2 : ^M1/M = 0,36
• n=3:^M1 _/M=0,27
• n =4 ?=0,21

If it is desired that the partial amounts be dosed over n passages, the total amount of dye is

This gives for

• n = 1 0.52
• n = 2: ^M1 / M = 0.36
• n = 3: ^M1 _{/ M} = 0.27
• n = 4? = 0.21

This example shows that even in the extreme case where n = 1 is selected, 48% of the dye can be distributed evenly during the first passage in the process according to the invention. Practice then also showed that dividing the amount of dye into only two subsets is often sufficient to ensure uniform color distribution.

After this dosing of n aliquots of the dye, the critical period for color absorption is over as the equilibrium state approaches. The remaining dye absorption then takes place in traditional passenger walking without the risk of irregularities.

The invention has been illustrated with reference to the drawing.

This shows a schematic diagram of a high pressure jigger for practicing the method according to the invention. 1 is the high-pressure container, 2 is the jigger tub with the dye liquor or the bath 3. Above the tub, the jigger has two rolls 4 and 5, onto which the material web is alternately unwound and wound, as it passes through the bath during such a passage 3 happened around two bottom rollers 6 and 7. The jigger also has a circulation pump 8 for the dye bath, which is connected to the tub 2 by pipes 9 and 10. In the connection of the circulation pump, a metering device 11 for dye is provided.

Since the roll 4 is assumed to be the take-up roll during a given passage, the fabric web moves in the direction shown by the arrows, and a length of the fabric web corresponding to the distance between points A and B via the bottom rollers 7 and 8 is always immersed in the bathroom. This length is of the order of 2 m. The drive devices of the rollers 4 and 5 are not shown, but they are of a well known type and such that the web of fabric moves at a mainly constant speed.

In the method according to the invention, only auxiliaries such as. B. leveling agents, metal complexing agents and the like, but not dye, added to the bath from the beginning. The jigger is then actuated and the bath is heated to the temperature range that is optimal for color absorption. During this heating period, the fabric web can pass one or more passages through the colorless bath so that there is a temperature equilibrium between the bath and the fabric roll when the desired temperature has been reached. At this time, while the jigger is stopped, the first portion of the dye is added all at once, and when the jigger is actuated, the metering device 11 is opened and a second portion of the dye is metered evenly over the course of the first passage. In this way, it continues during the second and third passages, etc. until all aliquots of the dye have been added. However, as mentioned above, it is often sufficient to divide the amount of dye into two portions only, ie that all of the dye has been added after the first passage. When all the dye has been added, a traditional passage process is continued until the desired shade has been achieved, ie a number of passages known from experience which depend on the textile fibers concerned and the dyes used.

If one speaks of the jigger standing still above, it should be understood here that the jigger does not carry out any passage process of the tissue web. However, it can perform an oscillation while standing still, i. H. that the jigger makes short back and forth movements at one end of the tissue in order to avoid a side weight of the rollers.

Claims (1)

1. A method of dyeing textile fibres on a jigger, wherein the required amount of dyestuff is divided into two or more portions, characterised in that the first portion is added to the dye bath while the jigger is stationary and in the meantime the dye bath is heated to the temperature range for optimum dyestuff absorption, and in that after actuation of the jigger the other portion or portions of dyestuff is (are) introduced into the dye bath linearly as a function of the amount of fabric which passes through the dye bath, wherein the number of passes of the amount of fabric through the dye bath corresponds to the number of portions of dyestuff and the dye bath has a temperature within the range for optimum dyestuff absorption.

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