How to control the fastness of various fabrics？

After dyeing of textiles, the ability of fabrics to retain their original color can be expressed by testing various dye fastnesses. Commonly used indicators for detecting dyeing fastness include washing fastness, rubbing fastness, light fastness, sublimation fastness and so on.

The better the washing fastness, rubbing fastness, light fastness and sublimation fastness of the fabric, the better the dyeing fastness of the textile.

The main factors affecting the above fastness include two aspects:

The first is the performance of the dye

The second is the formulation of the dyeing and finishing process

The selection of dyes with excellent performance is the basis for improving the dyeing fastness, and formulating a reasonable dyeing and finishing process is the key to ensuring the dyeing fastness. The two complement each other and cannot be neglected.

Washing fastness

The washing fastness of fabrics includes two aspects: fading fastness and staining fastness. Generally, the worse the color fastness of textiles, the worse the color fastness.

When testing the staining fastness of a certain textile, the staining of the fiber can be determined by examining the staining of the fiber to the six commonly used textile fibers (the six commonly used textile fibers usually include polyester, nylon, cotton, etc.). , acetate, wool or silk, acrylic fiber. The test on the color fastness of the six fibers is generally completed by a qualified independent professional inspection company, which is relatively objective and fair)

For cellulose fiber products, the washing fastness of reactive dyes is better than that of direct dyes. The dyeing process of insoluble azo dyes, vat dyes and sulfur dyes is more complicated than that of reactive dyes and direct dyes. Therefore, the washing fastness of the latter three dyes is more complicated. degree is more excellent.

Therefore, to improve the washing fastness of cellulose fiber products, it is necessary not only to choose the correct dye, but also to choose the correct dyeing process. Appropriate strengthening of washing, strengthening of color fixing and soaping can significantly improve the washing fastness.

For polyester fiber with deep color and luster, as long as it is fully restored and cleaned, the washing fastness of the fabric after dyeing can meet customer requirements. However, since polyester fabrics are mostly softened by padding cationic silicone softeners to improve the fabric feel, and at the same time, the anionic dispersants in disperse dyes may diffuse to the surface of the fibers due to thermal migration of the dyes when the polyester fabric is set at high temperature. The washing fastness of polyester fabrics with strong colors may be unqualified after setting. This requires that not only the sublimation fastness of disperse dyes, but also the thermal migration resistance of disperse dyes should be considered when selecting disperse dyes.

There are many ways to test the washing fastness. According to different testing standards, the washing fastness of textiles will be tested, and the conclusion will be drawn. When foreign customers put forward specific washing fastness indicators, if they can put forward specific testing standards, it will be conducive to smooth communication between the two parties. Although the strengthening of washing and post-treatment can improve the washing fastness of the fabric, it will also increase the emission reduction of the dyeing factory.

Finding some efficient detergents, rationally formulating dyeing and finishing processes, and strengthening research on short-process processes can not only improve production efficiency, but also contribute to energy conservation and emission reduction.

Rub fastness

The rubbing fastness of the fabric is the same as the washing fastness, and it also includes two aspects:

One is dry rubbing fastness and the other is wet rubbing fastness.

The dry rubbing fastness and wet rubbing fastness of the fabric are obtained through the testing of the fabric rubbing fastness testing instrument. Very convenient.

Usually, when testing the rubbing fastness of dark-colored textiles, the grade of dry rubbing fastness is generally about 1 level higher than that of wet rubbing fastness.

Taking direct dyeing of cotton fabric black as an example, although it has been effectively fixed, the level of dry rubbing fastness and wet rubbing fastness will not be very high, and sometimes it cannot meet customer requirements. In order to improve the rubbing fastness, reactive dyes, vat dyes and insoluble azo dyes are mostly used for dyeing. Strengthening dye screening, strengthening color fixing treatment and soaping are effective measures to improve the rubbing fastness of textiles.

In order to improve the wet rubbing fastness of dark-colored cellulose fiber products, special additives that can improve the wet rubbing fastness of textiles can be selected. Spend.

For chemical fiber filament dark-colored products, the wet rubbing fastness of the product can also be improved by adding a small amount of fluorine-containing water repellent when the final product is finalized.

When acid dyes are used to dye polyamide fibers with a deep color, the use of a special nylon fixing agent can significantly improve the wet rubbing fastness of the nylon fabric with a deep color.

For sanded dark-colored products, when testing their wet rubbing fastness, the shedding of short fibers on the fabric surface of sanded products will be more obvious than other products, so the wet rubbing fastness grade may be lowered.