How To Improve The Color Fastness Of Reactive Dyes

Textile printing and dyeing industry is facing unprecedented opportunities, but also faces severe challenges.

By increasing inspection efforts and difficulties, foreign businessmen are doing everything possible to set up green technology barriers to restrict China's textile exports.

The main problems found in the inspection of export textiles are:

Poor and dimensional change rate is not qualified and hazardous substances exceed standard.

The rate of dye fastness was 20% to 30%.

Mainly cotton and cotton blended dyed fabric wash, wear resistance, water stains and sweat stains fastness does not meet the requirements.

Reactive dyes accounted for more than 70% of cotton dyes.

Generally speaking, reactive dyes can be treated without fixation. In the process of production, the production of hydrolyzed dyes can be reduced by promoting the bonding of dyes and fibers, and the flooring will be enhanced by washing to ensure the fastness of dyed products.

However, after dyeing, there are certain restrictions on washing. Some of the hydrolyzed dyes and unfixed dyes are difficult to wash. In the process of washing and taking, they also cause hydrolysis of the bonded dyes to break off, causing the dye to fall off the fibers, causing discoloration or fading.

For this reason, dyeing plants need to fix their colours after dyeing to improve their fastness.

For a long time, the fixing agent Y has been widely adopted by domestic dyeing factories and occupies a huge market share.

Although the fixing agent is quite practical, it is a condensation product of dicyandiamide and formaldehyde, which easily leads to higher free formaldehyde content after fabric treatment, which makes the ecological detection items of dyeing products exceed the standard.

Therefore, it is more and more urgent to develop formaldehyde free fixing agents with excellent performance and excellent fixation effect.

In this paper, through the practice contrast, the color fixing agent H-8 produced by de Mei Chemical Co. Ltd. is used to improve the dyeing fastness of reactive dyed products, and the effect is excellent.

At present, there are mainly three types of fixing agents: A. cationic surface active dosage form, B. non surface active quaternary ammonium type, and C. cationic resin type.

Different fixative treatment effect is different. After treatment, some of the dyed products can improve the soaping fastness, but the water and sweat fastness is still poor. Some of them even reduce the original fastness of sunlight or change the color of the dyed products. The cationic resin fixing agent has the best comprehensive effect and the most widely used treatment.

Fixing agent H-8 is this type.

It can be associated with

Anionic binding produces insoluble salts, blocking the water-soluble groups of dyes, thus enhancing the wet fastness of dyes, but has no significant effect on color and sunlight fastness.

The fixing agent H-8 contains no formaldehyde and does not irritate the skin. It is an environmental friendly fixative and meets the requirements of ecological textiles.

Production practice.

The fabric is 40 x 40133 x 72 and all cotton mercerized plain dyed dark brown.

Dyeing.

The process is to dip the dye solution (one dip, one rolling, the remaining rate 70%) to pre drying, drying, rolling alkali to steam (102 60s *) to flat washing, drying, then rolling fixative to drying and finishing.

Test method for waterborne color fastness is tested by American Standard AATCC107.

The color fastness to soaping was tested by American Standard AATCC61 2A.

The color fastness to abrasion is tested by American Standard AATCC8.

The color fastness to sunlight was tested by American Standard AATCC16H.

Formaldehyde content was tested by ISO/FDIS141811.

Judging from the test results,

The color fastness to water stains and soaping resistance before fixing is poor. After fixing, it can be improved to a certain extent. However, the fixing agent Y has a great influence on the color of the dyed products, which will reduce the fastness to light and increase the formaldehyde content of the fabric after fixing.

The fixing agent H-8 can greatly improve the wet fastness of dyed products and has no other adverse effects.

It has been proved by practice that dyeing fastness of reactive dyestuffs has been improved obviously by proper fixing agents, especially for dark fabrics.

The use of environmentally-friendly fixative H-8 to make dyeing products conform to the requirements of ecological textiles, and lay a solid foundation for breaking through the green barriers of European and American countries and enhancing the international competitiveness of enterprises.