Introduction
In the textile industry, sodium alginate is an excellent raw material for preparation of warp sizing and dyeing pastes. Especially in the printing and dyeing industry, sodium alginate has good washing out, high paste off rate, the film formed after printing on fabric has certain adhesion and flexibility. It does not react with dyes and other auxiliaries, the film formed after the film even after baking or high-temperature steam, it will be easily removed in the washing process, so that the hand feeling of the fabric is soft.
REACTIVE DYEING
Sodium alginate is an ideal thickener in reactive dye printing as it can not react with reactive dyes. In the molecular structure of sodium alginate, -COONa is negatively charged in water, so sodium alginate is negative. Because there arecarboxyl, sulfonic acid groups in the matrix of the reactive dyes and they are ionized in the water and has a negative charge, so that the reactive dyes also have a negative charge. The electrostatic repulsion prevents the binding of reactive dyes with sodium alginate so it can promote the dye rate. While others such as paste, starch, synthetic tragacanth, printing paste should not be reactive, because their molecules contain a large number of hydroxyl groups, and its easy to bond with active groups to make the color light and easy to be washed out.
DISPERSE DYEING
Disperse dyes are used in synthetic fibre printing, and the fine printing effect can be obtained by using sodium alginate as thickening agent. As the majority of synthetic fiber has the characteristics of hydrophobic absorption, less printing paste, we usually choose low viscosity sodium alginate, preparation of high solid content paste and the dye particles are uniformly dispersed in the paste to improve the printing effect.
Advantage
1、High purity and stability.
2、Good filtration, high permeability rate.
3、Easy to color and good washing out.
4、Clear and bright pattern
5、Low consumption
