How to improve printing dyeing fastness to meet the increasingly fierce textile market demand, has become a research topic of printing and dyeing industries. In particular, the rectivary dye is sunshire fastness, the wet rub fastation of the deep concentrate fabric; the wet treatment fastness caused by the thermal migration of disperse dyes is decreased; and high-to-chlorine fastness, and sweat-resistant Light fastness, etc.
There are many factors affecting color fastness, and there are many ways to improve color fastness, I have passed many years of production practice. In terms of choosing a suitable dyeing agent, improving the dyeing and finishing process, strengthening process control, explores some methods and measures, has certain improvements and improvements in dyeing fastness, basically meet market demand.
1 Active dye light-colored fabric sun fastness
It is well known that Active dye on cotton fibers, under the sunshine attack, the chromophore or auxiliary group in the dye structure, which will be disrupted to different degrees, and cause color change or color, that is, the sun is fastness problem.
Chinas national standards have long been stipulated in the light-resistant fastness of the active dyes, such as GB / T411-93 cotton printing dye standard specified that the staining cloth tolerance of active dyes is 4-5 Level, printing cloth to light up 4; GB / T5326 combed polyester cotton mixed printing stamp standard and FZ / T14007-1998 Cotton-mixed printing cloth standfaction stipulates, dispersion / active dyeing cloth tolerance is 4, printing The cloth is also 4.
Active dye is more difficult to achieve this standard to achieve this standard.
The relationship between dyeing parent structure and sunlight
Japanese days of active dyes The sun effusion is mainly related to the parent structure of the dye, 70-75% of the active dye parent structure is azo type, and the rest is a pyroxin type, phthalocyanine type and an A-form.
The azo type light tolerance is poor.
The yellow active dye molecular structure is azo type, the parent chromogen is optimal, the active dye of the blue spectrum and the activated dye of the blue spectrum with pyrazolinone and naphthalene trisullonic acid. With the structure of anthraquinone, phthalocyanine, maternal structure, the sun is very fast, and the red spectrum active dye is azo type.The sunsian fastness is generally low, especially light colors.
The sunlight fastness of the staining sample changes with the dyeing concentrationDifferent, the same dye is staining on the same fiber, and its sunsia fastness increases with the increase of dyeing concentration, mainly due to the change in the distribution of aggregate particles on the fibers.
The aggregate particles are solarized, and the larger dye is exposed to air-moisture, the smaller, the higher the sunshine.The increase in dyeing concentration increases the proportion of large particles on the fibers, and the sunshine is also increased accordingly.
Low staining concentration of light-colored fabrics, the dye is lower in fibers, and most of the dyes have a single molecular state, that is, the dye is highly decomposed on the fibers. Each molecule has the same chance being affected by light and air, moisture, and the sun is declining.
ISO / 105B02-1994 Standard Day Sunset 1-8 Standard Assessment, Chinas national standards are also divided into 1-8 standards, AATCC16-1998 or AATCC20AFU standard day Radios 1-5 standard assessment.
Therefore, first, it is necessary to make a clear customer requirement, all dye production enterprises or companies including quot;dye indexquot;, the dyeing day, the dyeing day, sunset, The data measured in the case of the dye depth 1/1, that is, the data measured on the Chinese color fabric of about 20-30 g / L, the light-colored fabric is less than this level.
Measures to improve sunlight
1 , The use of dyes affects light-color fabricThe main factor in sunshine is the dye itself, so it is most important to use dyes.
When the dye is selected, it is necessary to make the light fastness level of each component dye of the selected amount, as long as any of the components, especially the least amount The lightweight fastness of the division does not reach the light color dyeing, the light fastness of the final dye is not met.
2, other measures
(1) Effect of floating dyes.
Dyeing soap is not thorough, and the unlimated dye and hydrolyzed dye remain on the layout will also affect the light fastness of the pigment, and their light fastness is significantly lower than that Active dye.
The more soap washing, the better the light tolerance.
(2) Effect of Soil and Soft Agent.
Cationic low molecular or polyamine condensation resin forming fixation and cationic softener are applied to the fabric finishing, which will cause the sunlight fastness of the pigment.
Therefore, it is necessary to pay attention to their effects of sunlight sunstrois in the sun.
(3) Effect of ultraviolet absorbers.
Ultraviolet absorbers have recently used for light-colored chromosomes to improve sunlight, but must have a lot of effect, not only increase cost, but also caused fabric yellow and damage. Therefore, it is best not to use this method.
2 Wet treatment of deep concentrate of active dye
In recent years, it has been difficult to use in active dyes and other dyes. The active dye is imparted by a covalent bond to impart excellent dyeing fastness, but the deep concentrated color is often faded and staining phenomenon, and these phenomena have occurred in addition to part of the dye matrix due to light, hot, sweat, acidity. Erosion of gas and oxidant, azo-based decomposition, complex metal ion detach, amino oxidation or the like, or the like, causing the color change and fading.
The breakage of the dye-fiber bond also causes fading and staining. The floating color on the chromosome is to cause water washing fastness of deep concentrated chromosomes.
Some dyes will leave a floating dye on the fabric after dyeing, and the floating dye of the active dye contains some hydrolyzed dyes, adsorbed to the fiber without participating in covalent reactions. Dyes, these floating dye clearance is related to their directness of the fibers, wherein the directness is the highest of the vinyl sulfone group dye, followed by hydrolyzed dyes, unreacted dyes due to a sulfur ester water soluble group, so the smallest fiber It is the easiest floating dye that is the easiest to remove. Practice has proved that even after full water (soap) washing, there is still some residual floating dye on the fibers, the larger the directness of the active dye, the less floating dyes are not easy to be from the fiber. Clear down, and it has water soluble, and it will be dissolved in the water, and the other fabric is contaminated, they are the residual dye depth concentrated fabric wet treatment fast, including water washing, soaphed and wet friction fastness The main reason.It is necessary to clear the floating dye to consider both dye selection and process rationalization.