Brief Introduction Of Mercerizing Technology

Cotton products (yarns, fabrics) are treated with concentrated caustic soda under tension conditions, and then wash the caustic soda under tension.

Alkali shrinkage: cotton products are treated with concentrated caustic liquor in a relaxed state, so that fibre can shrink arbitrarily, and then wash away the caustic soda process, also known as tension-free mercerizing. It is mainly used for processing cotton knitwear.

The characteristics of mercerizing and alkali shrinkage fabrics.

After mercerization, the fabric has the following changes: gloss enhancement, adsorption capacity, chemical reaction ability, shrinkage rate, dimensional stability, fabric smoothness, strength and elongation. Mechanical properties of the fabric have been changed. Alkali shrinkage can not improve the fabric luster, but it can make yarn yarn become more compact, elastic and feel full. Besides, the strength and adsorption capacity of dye are improved.

Process arrangement.

First bleed after silk; mercerizing effect is good, waste alkali is net, but whiteness is poor, easy to stain, suitable for color cloth, especially heavy fabric.

First silk and then bleach: good whiteness, but poor luster. Fibre is easily damaged during bleaching. It is suitable for bleaching cloth, printed cloth, and mercerizing after dyeing. It is suitable for easily scratched or.

The handle is hard and dyed fast. When dyed dark, in order to improve the surface effect and color fastness of the fabric and some varieties that require high gloss, it can also be dyed with mercerizing.

Raw green mercerizing: some dark colored varieties (aniline black) can be directly carried out mercerizing after burning, cellulose sodium salt ionize to produce an unmovable cellulose anion Cell-O. There are still mobile Na and OH- in the solution. If there is NaCl, there is Cl. The fiber surface is considered to have semi permeable membrane properties. These ions are distributed according to certain conditions to achieve equilibrium.

But the waste alkali contains many impurities, which brings trouble to recycling.

Semi mercerizing before dyeing and conventional mercerization after dyeing: in order to improve the adsorption and chemical reactivity of dyes.

Cotton mercerization, mercerizing, mercerizing and wet mercerizing are two kinds of wet mercerization. Because wet cloth mercerizing is more difficult to control, the dry cloth is more mercerized.

Other alkali metal hydroxides also have a certain expansion effect on cellulose fibers, but their expansion capacity is higher and the cost is higher with the increase of atomic weight. Therefore, only caustic soda has practical value. Some acid and salt solutions (H2SO4, HNO3) can also make cellulose fibers puffed and get mercerizing effect, but the actual production is difficult and lacks practical significance.

Anhydrous liquid ammonia is also an excellent puffing agent because of its small molecule and high purity. It has not been studied in 1960s. Its luster and dyeing properties are not as good as alkali mercerizing. However, its soft handle, dimensional stability and crease resistance are relatively high. In recent years, it has been used as a new process for liquid ammonia finishing combined with the application of mechanical shrinkage and resin finishing.

Gloss is a measure.

One of the main indicators of appearance effect.

We can use variable angle spectrophotometry and polarized light method, but there is no unified ideal testing method.

Microsection observation of fiber morphology, adsorption capacity barium method: is a commonly used method to test mercerizing effect, barium value is large, mercerizing effect is good, cotton barium value =100, barium value >150 indicates full mercerization, generally 135~150.

Iodine staining and staining test method: different barium (100~160) samples were treated with direct blue 2B dye solution of or of iodine in certain concentration, and then the color cards were made. Then the iodine contamination of the unknown samples and the dyeing depth were compared with the color cards, and the mercerizing barium value was quantitatively evaluated.

Dimensional stability.

The shrinkage of the fabric before and after treatment is measured by mechanical shrinkage or impregnation shrinkage. The shrinkage rate is usually calculated by the formula, and the shrinkage rate is usually larger than the zonal direction. However, some of the varieties with higher density have negative shrinkage.