Analysis Of Basic Conditions For Mercerizing Process

The basic conditions are the concentration of NaOH solution, temperature, time of action, tension and alkali removal.

Alkali concentration is the main factor affecting mercerizing effect.

Cotton fiber with different concentrations of caustic soda solution after treatment, the length and diameter of the change: concentration >8%, diameter increased, the length shortened to the maximum, cotton yarn in different concentrations of NaOH solution shrinkage and dyeing, cotton mercerization on the concentration requirements (C and contraction and barium value relationship), C= 177g/L, the barium value is 150, C=245g/l, barium value is the highest.

C=240~280g/l, the shrinkage tends to be stable.

Therefore, the best caustic soda concentration for mercerizing is about 245g/l. Considering the alkali absorption of fabric and alkali consumption in the air, the mercerizing soda concentration of cotton cloth is 260 ~ 280g/l.

In actual production, it can be selected according to the quality of semi-finished products and the quality requirements of finished products.

The effect of tension on fabric lustre is that only when the cotton fabric is treated with strong alkali, it can be displayed with good luster only if the proper tension is applied. The effect of tension on the properties of cotton yarn mercerization can be seen: the tension is large and the gloss is good.

The effect of tension on the mechanical properties and adsorption properties of fabrics is that the strength of cotton yarns has been improved under the condition of inability. If the appropriate tension is applied, the strength can be further improved, but the gloss increases little, and the fracture elongation and adsorption properties decrease.

The influence of tension on the shrinkage of fabrics is very important.

In actual production, the shrinkage ratio of warp and weft fabrics of various specifications is unbalanced.

Khaki, Fu tune and other fabrics with higher density have a higher shrinkage rate than the zonal shrinkage, so the meridional tension is preferred.

It is necessary to ensure that the caustic soda is rapidly and evenly distributed and penetrated into the inner part of the cotton or fabric and fiber.

When the cotton yarn is used for 280g/lNaOH under the condition of no tension, it is found that the yarn shrinkage rate and the dye absorption rate reach the maximum value at 20s time. The extension time is not significant to enhance the mercerizing effect.

In addition, the time is related to the alkali concentration and temperature. When the concentration is low, the action time should be appropriately extended; generally 50 ~ 60s.

Alkali removal has a great effect on the shaping effect of mercerizing. If the tension is relaxed, more than 5% alkali is still on the fabric, the fabric will shrink, which will affect the gloss and the weft shrinkage rate.

De alkali is divided into two steps: (1) under the condition of enlargement, the hot and dilute alkali is used to rinse the fabric with flushing device.

Commonly used

There are cloth mercerizing, bending roll mercerizing and straight roller mercerizing machine.

The cloth mercerizing machine has the best effect and the most extensive application.

The difference between the bending roller mercerizing machine and the cloth mercerizing machine is mainly in the expansion and initial washing parts, and the expansion part is composed of a shallow flat step iron groove and 10~12 pairs of bending rollers.

The enlarging effect is widened by the zonal force generated by the fabric around the curved camshaft of the curved sleeve.

In the process of bending roll mercerizing machine, two layers of fabric are often folded together, and the output is higher, but the efficiency of alkali washing is low and the expansion effect is poor.

Although it has the advantages of short fuselage and single tube structure, it is easy to produce uneven density, and the weft yarn is curved and moon shaped.

Straight roller mercerizing machine and the first two different is that there is no rolling and cloth roller, nor expansion device.

Features: double deck, high yield, uniform mercerization, no break edge, short fuselage, simple pmission and easy operation, but the expansion effect is poor (the drawback shrinkage rate is difficult to reach the national standard), which is the main drawback.

Some factories in China use cloth and straight roller to solve this problem.