This method is used for PVA-based mixed pulp (including starch) and PA-based slurry.
Desizing principle:
Starch and chemical pulp under the action of hot caustic soda, strong expansion, adhesion to the fiber becomes loose, from the gel state to the sol state, the chemical pulp increases solubility in the hot alkali, and is easily washed from the fabric by effective water washing. Washed off, while the hot caustic soda solution can remove a part of natural impurities, especially suitable for cotton cloth containing more cottonseed husks. Most of the alkali used for desizing is scouring or mercerizing waste alkali, which is low in cost and does not damage the fiber, so this process is widely used in printing and dyeing factories. The desizing rate of alkali desizing is about 50~70%, and the remaining slurry can only be further removed during scouring.
Features:
- The cost is low, and the waste alkali liquor in the pretreatment can be utilized;
- It helps to remove the fiber from the remover of the cottonseed hull, reduce the refining burden, and has good whiteness and permeability;
- It has a role in all kinds of slurry;
- The desizing rate is not high, and the stacking time is long, which hinders the continuous production;
- The alkali has no chemical degradation effect on the PVA slurry, the viscosity of the water washing liquid is large, and the water washing should be sufficient to prevent the slurry from re-staining the fabric.