DE2063179B2 - METHOD OF DYING SPINNING CABLE IN THE HYDRATED STATE - Google Patents

Description

The present invention relates to a process for continuous dyeing by the wet spinning process produced fibers, in particular of tow in the hydrated state, in which the fibers with adjustable speed after fiber formation moved by a counter-flowing dye liquor will.

Fibers made of polyacrylonitrile are obtained by the so-called dry spinning process, in which the fiber is produced from a solution of the polymer in organic solvents by evaporation of the solvent, or by the so-called wet spinning process, in which the fibers are precipitated in aqueous solution with the addition of electrolytes. In the so-called wet spinning process, following the actual fiber formation process (spinning process), the fiber is first subjected to a few washes and then stretched to orient the macromolecules before it is dried. In this "swollen" gel-like state, the fiber ₄ u is able to absorb dyes to a particularly high degree, e.g. B. from aqueous liquor, a dyeing in this state can therefore take place under much milder conditions than are required for dyeing the same, but then dried fiber after spinning. There is thus a saving in energy and time when dyeing tow in the hydrated state; in addition, a drying process can be saved.

The previously known processes for dyeing fibers in a gel-like state consist essentially in the fact that the fibers either on a padder or in a simple The dye bath is brought into contact with the dye liquor and then washed hot. As the fiber at a continuously running process constantly removing dye from the dyebath are known Process for achieving a certain color tone requires specific equipment measures, which guarantee that the dye concentration in the dye bath is kept constant. Such measures are e.g. B. the measurement of the dye concentration and a control of the replenishment of dye liquor, z. B. over an electronic control system, inevitable. If a dye mixture is used for coloring, like that in is generally the case, the individual dyes must be separated according to their coloring behavior be replenished, which requires a separate control of the individual dye liquors. Such control systems are very complicated and expensive, and often tend to cause the control variable to oscillate.

In the German Offenlegungsschrift 14 60 343, such a method is described in which the relative speed of textile goods to the dye liquor is adjustable and in which a colorimetric analysis of the dye bath is carried out, according to which the amount of dye is added to the bath, which of the Textile product is included in the treatment. However, this method has the aforementioned Disadvantages on.

The object of the invention is to create a process in which the wet spinning process manufactured fibers, especially polyacrylonitrile tow, continuously in the hydrated gel state in a simple manner without prior drying can be colored without having to use complicated and expensive control equipment. This task is achieved by the fact that the relative speed of the fibers to the dye liquor and the dye concentration the dye liquor at the fiber exit point from the Dye liquor are adjusted so that the dye concentration of the dye liquor at the fiber entry point is approximately zero.

The application of the countercurrent principle for practicing tow in the hydrated state is at Setting the dye concentration of the dye liquor in the manner according to the invention is very economical and enables the fibers to be produced in certain colors and with a degree of exhaustion of almost 100% using the continuous process to color.

The advantages of the new process are that the dye used is practically complete can be used and that no oscillation of the color strength of the colored fibers occurs, as in Systems that are based on a measurement of a variable and a control derived from it (re-dosing) are based. Furthermore, the problems of ending inequality are circumvented by adding each part of the Fiber material is brought into contact with fresh dye liquor at the end of the dyeing process.

According to the invention, the dye liquors customary in practice can be used. They become functional prepared in such a way that the dye is dissolved or dispersed in water and the dye liquor obtained with acid and / or a buffer salt to the desired adjusts the pH value.

Both disperse dyes and anionic and, in particular, cationic dyes can be used be used. The dyes can belong to any class.

The method according to the invention is explained in more detail using exemplary embodiments. In the drawing shows

F i g. 1 shows an embodiment of a device for carrying out the method according to the invention in schematic sectional view and

F i g. 2 shows a section along the line H-II in FIG. 1.

The dyeing machine shown consists essentially of a series of vessels Si, 52, Ss, St, a leading through these vessels transport device G, H for tow F, a mixer, L for the preparation of the dye liquor, and a metering pump K. The outlet of the mixer L is connected via the metering pump K to the last vessel S4 in relation to the transport direction. The vessels Si, Si, S2, St communicate with one another via overflows D. There are in the vessels

Guide plates C mounted, which wrestle the dye liquor in a countercurrent to the transport direction of the spinning rope F «. The first vessel is provided Si n £ effluent with a überlaufarti _as. A double jacket for φα heating medium for thermostating the row of vessels is drawn with manure.

The operation of this Färbeaggregate- is as follows: The mixed in the mixer L dye liquor by the metering pump K, possibly after prior dilution to the point A conveys the last vessel and the Färbeaggregats through the guide plates C, the dye liquor is forced in countercurrent direction through point B to flow downwards and then flow again at point D from the last vessel Si into the penultimate 53 g). The dye liquor now passes through all of the vessels Si, S3, Si, Si in the same amount, in order to finally exit again from the first vessel Si at point E. The tow F, which has undergone the usual treatment after the spinning process, is first immersed in the first vessel Si. The dwell time within a vessel depends on the one hand on the speed of the tow transport and on the other hand on the dimensions of the individual vessels.

It is on the order of about 0.1 to 30 seconds. The tow F is thus brought into contact with the least concentrated dye liquor for 2 seconds, absorbs a certain amount of dye from this, then passes into the next vessel S2 where the dye concentration is higher. In this way, the tow F is in contact with the fresh dye liquor at the end in the last vessel S4, so that, after the state of equilibrium has been established, the depth of color of the emerging tow F is constant at point /. The transport devices G and H are designed so that the tow F is distributed as widely as possible through the individual vessels Si, S2, Si, St, so that the penetration of the dye liquor into the tow F is optimal.

The depth of color is controlled on the one hand by varying the concentration of the Far'oflolte in mixer L, on the other hand by varying the amount of dye liquor given by the metering pump K. With constant concentration in mixer L and constant metering rate, Si, S2, S3 are produced in the individual vessels , Si equilibrium concentrations which _{decrease from the 4} s vessel St to vessel S3, S2, Si. The optimum setting is achieved when the concentration of the dye liquor emerging at outflow E is approximately zero, since in this way almost complete utilization of the dye is achieved. The time for <, ₀ adjust the equilibrium depends on the size of individual vessels, it is less so, the smaller the volume of the vessels. Since the speed of the dyeing process and the dye equilibrium concentrations achieved depend on the temperature of the dye liquor, it is advantageous to surround the entire dyeing unit with a double jacket M. For dyeing hydrated polyacrylonitrile cord! a temperature in the range between 20 and 70 ⁰ C should be able to be maintained.

In the following examples the temperatures are given in Ceisius degrees.

Examples

Dyeings are carried out in a dyeing unit which consists of 5 consecutive vessels Si to Si , which are constructed in such a way that they allow an immersion time of 0.7 sec / vessel at a tow speed of 0.5 m / sec. This corresponds to an immersion length of 0.35 m / vessel. Such a dyeing unit is shown in FIG. 1, but the individual vessels Si to Ss are arranged in a cascade.

At G, the dyeing unit is continuously fed with polyacrylonitrile tow, which is made from a solution of polyacrylonitrile in sodium thiocyanate by the wet spinning process and, as is customary in the art, stretched, washed but not dried at 95 °. The water content of the tow is reduced to around 170% of the dry weight by squeezing off the excess water. The amount of tow entering the dyeing unit at G is shown in Table II.

An aqueous solution of a dye, the composition of which is given in Table II, is mixed in the mixer L and added to the vessel Ss with the metering pump K at a constant metering volume at A , taking care that the dye liquor is distributed over the entire width of the vessel .

The tow, colorless at G , is successively dyed in the individual vessels Si to Ss and leaves the dyeing unit when / in the dyed state.

The dye liquor adhering to the hole is removed by two nip rollers and discarded. The colored spinning cabbage! is then briefly rinsed in hot water and then dried. The concentration of the dye liquor slowly decreases from vessel Ss to Si, so that the dye liquor leaves the dyeing unit at E in an approximately colorless state.

At the beginning of the dyeing process, all vessels are first filled with water. After a few minutes there is a A state of equilibrium with regard to the concentration of dye in the individual vessels has been reached. After that remains the color of the dyed spinning cable at a constant metering speed and at a constant metering concentration constant over a longer period of time.

The following table 1 shows the constitutions of the dyes used:

Table 1

I. Dye of the formula

O-N

NN

C!

Cl

CH ₁ (H,

continuation

II. Dye of the formula

ι Ii / ■ - / —t

H, C-N-CH ₁ -C- ^ f ^; -n = --- N-C NH

<CH,

1. Dye of the formula

CH ₃ O

IV. Dye of the formula

V. Dye of the formula VI. Dye of the formula

Cl

CH,

-N-CH ₂ CH ₂ OH C ₂ H ₅

QH ₅

ZnCI ₃

N:

Il

CH ₃ C-NH

HO

O NHCH,

Cl

VIl. Dye of the formula

VIII. Dye of the formula

CI

O NHCH ₁ CH ₁ OH

NH,

HO

SO ₃ Na

C ₂ H ₅

SO,

NH,

, V-N- N - V

HO

SO ₁ Na

continuation

IX. Dye of the formula

• N

NaO ₁ S

N -Γ

NaO = S

/ Νχ

cn cn

SO ₁ Na

SO ₁ Na

The following Table II gives the components used in Examples 1 to 9, their amount and dit Dyeing conditions again. At the end of the example, the hue in each case is that colored according to the invention Polyacrylonitrile fibers indicated.

Table II Examples 2 3 4th 5 6th 7th 8th 9 dye 1 I. I. Il 11: 1.5 g / l Hi: V: 35 g / l VII: VIII: I. I: 3.8 g / l 4.3 g / l V !: 7 g / l 88 g / l 12.6 g / l Hl: IV: IX: 62 g / l 6.1 g / l 0.12 g / l 43 43 160 43 Concentration of the trunk 2 2 3 2 6th - - - solution, g / l 2 2 2 3 2 2 - - - Acetic acid, conc., G / l 2 4.6 4.6 4.6 3.4 3.7 6.8 6.4 6.4 Sodium acetate, conc., G / l 4.6 30th 30th 35 50 22nd 48 25th 55 . PH 30th 110 110 260 100 130 165 110 60 Temperature, ° C 110 Dosing amount, stock solution, 1700 850 850 800 800 700 1250 1700 ml / min 1700 50 50 30th about 25 about 25 55 30th 55 Dosing amount, water, ml / min 25th 48-42 48-42 38-32 ! 38-26 37-25 42-53 35-28 43 54 Water temperature, ⁰ C 36-25 Temperature in vessel 430 430 430 430 430 430 430 430 Si up to 5s, ⁰ C 430 PAC tow quantity, g / min Relative dye concentrations trations *) in equilibrium 69 77 92 - - - 66 - State 80 44 42 56 - - - 41 - Vessel S \ % 54 25th 18th 35 - - - 25th - Vessel Sa, % 28 12th 7th 18th - - - 16 - Vessel S3,% 10 7th 3 8th about 2 2 - 11th - Vessel S2,% 4th 0.2 0.5 2.4 about 0.2 2 about 6 4th about 8 Vessel Si,% 1.6 93 96 91 98 98 about 86 88 about 84 Squeezed solution,% 95 1.02 1.06 4.4 0.24 0.13 1.4 1.96 0.87 Degree of exhaustion,% 1.05 dark dark yellow Gray blue green Red orange Color depth achieved "),% dark Red Red Hue of the colored poly- Red acrylonitrile fiber dry Fiber. ·) Conc. At increase = 100%.
· *) Dye, based on the Ge weight of For this 1 sheet drawings

Claims (1)

Claim: Process for the continuous dyeing of fibers produced by the wet spinning process, in particular of tow in the hydrated state, in which the fibers move at an adjustable speed after fiber formation are moved by a counter-flowing dye liquor, characterized by that the relative speed of the fibers to the dye liquor and the dye concentration the dye liquor at the fiber exit point from the dye liquor are adjusted so that the Dye concentration of the dye liquor at the fiber entry point is approximately zero.