How To Solve The Problem Of Chromatic Instability And Cloud Like Flowers In Reactive Black Dyeing?

At present, there are many active black varieties on the market.

Such as reactive black KN-G2RC, reactive black GR, reactive black GWF, reactive black ED, reactive black GFF, reactive black TBR, etc.

These reactive dyes, due to their good dyeing depth and low price, have become

(fabric) preferred when impregnated with black.

However, these reactive black dyes are easily undulate in the dip dyeing process, and are prone to produce cloudy flowers. The root cause of the problem is the defects in the dyestuff composition.

Reactive black is not a single structure but a compound dye.

The common reactive black is usually made of high density C.I. active green 5 (60%~80%) and C.I. active orange 82 as a secondary color (10%~20%).

C.I. activity yuan Qing 5, equivalent to domestic active black KN-B, active Yuan green B, active Tibetan green B, active Tibetan green GD.

Its molecular structure is as follows:

Because the activity of C.I., Yuan Qing 5 is actually a bluish green with higher grayscale than it is.

Therefore, it is necessary to add a proper amount of blue dye, orange dye, to turn the blue light into gray to increase the blackening degree by mixing C.I. with reactive green 5.

Therefore, although the proportion of active orange is not large, it plays a decisive role in the chromatic light.

Once the dye amount is different, it will cause the color light fluctuation.

Commonly used orange dyes are generally C.I. active orange 82.

C.I. active azo 5 Series diazo parent sulfonyl reactive dyes.

C.I. active orange 82 is a mono azo parent, one of which has a middle temperature active radical of beta hydroxyethyl sulfone sulfate, and the other side contains a two chloro three azine active group.

It can be seen that the compatibility of C.I. activity yuan Qing 5 and C.I. active orange 82 is poor, and the requirements for dyeing conditions are quite different.

If it is applied in medium temperature reactive dyes, it will be dyed at 60?

60 dyeing at high temperature will cause a large amount of active orange components to hydrolyze because of the high temperature, resulting in a significant "blue" and dark blackening.

Moreover, it is easy to cause different degree of hydrolysis, resulting in the degree of "go blue" of the colored light, which is suddenly neglected and heavy, resulting in obvious chromatic aberration.

Dyeing at 60 C will result in excessive color of active orange due to high temperature, resulting in uneven colouring, resulting in a cloud like flower.

The conventional heating method of 60 HT C dyeing will cause weak affinity in the neutral salt bath, low color absorption at a time and a large amount of dye remaining in the dye bath, resulting in two times of excessive color absorption at the initial stage of alkali fixation.

This will result in uneven color and low color fastness.

But also because of excessive floating color, reduce black purity.

Obviously, C.I. active black green 5 mixed with C.I.82 active orange is mainly reactive black, but it is not a real medium temperature dye.

It is not appropriate to use conventional medium temperature reactive dyes in the conventional temperature rising method at 60?

The countermeasures are as follows:

(1) segmented staining

The so-called piecewise staining is actually a one bath two staining method.

That is, dyeing at low temperature of 35~40 C will make C.I.82 active orange uniformly absorb and fix.

Moreover, the temperature of 60 C.I.5 was increased to normal color.

The test proves that

It can meet the specific requirements of dyeing temperature for C.I. activity, Yuan Qing 5 and C.I. active orange 82.

Therefore, the two quality problems caused by different dyeing temperatures can be solved easily.

Moreover, as the process is dyed from low temperature (35~40 HT C) in weak alkaline bath (the actual pre dyeing method is used), the color absorption of C.I. activated yuan Qing 5 can be greatly improved.

It was found that under the same conditions, the amount of C.I. absorbed in the weak alkaline bath increased by 4 times than that in the neutral bath, when the activity of the C.I. was 5.

However, due to the weak alkalinity and the ability to pfer dye, there is usually no problem of uneven color absorption.

Because the concentration of dye solution was greatly reduced before adding alkali to fix the color, the sudden dyeing in the initial stage of fixation was significantly relieved, so that the levelling effect of reactive yuan Qing was obviously improved.

Because of this, the segmented dyeing process can fundamentally eliminate the hidden danger of such reactive black and ensure uniform color and stable color and light.

(2) alkali agents are applied separately.

The fixation of soda ash is applied first and then multiple times, so that the alkalinity of the dye solution is weakened gradually. This can effectively alleviate the two color rate of the dyestuff during the fixation stage, and will also achieve positive effects on leveling and stabilizing the coloured light.

(3) strengthen the detection of dye into the factory.

The production of reactive black is mostly mixed by wet process.

And every time we synthesize it.

A large number of active oranges produce a batch of active green mixtures.

Due to the poor stability of C.I. active orange 82, dyes will be hydrolyzed successively during placement.

Therefore, the reactive black mixed with the front and back will often be different from the 82 force of the C.I. active orange, resulting in certain differences in color and light and blackening.

Therefore, black light and force should be carefully tested to prevent the generation of chromatic aberration.

Among the commercially available reactive black, some of them are genuine reactive black in the true sense, because they completely abandon the C.I. active orange 82 and replace them with medium temperature active orange.

Commonly used medium temperature active orange has C.I. active orange 107.

C.I. active orange 107 is also an intermediate temperature dye.

Therefore, the dyeing property of C.I. is 5.

There is absolutely no performance defect brought by C.I. active orange 82, but the price is higher.

Therefore, it is not necessary to use the special staining method to dye.

However, this type of reactive black is still mainly composed of C.I. activity yuan Qing 5. In the initial stage of alkali fixation, two times of excessive color absorption, that is, the sudden dye phenomenon is prominent, which is not conducive to levelling.

Therefore, it is necessary to use the alkali dyeing method to increase the first color absorption and alleviate the "sudden dye" phenomenon.