Joinprofit group dedicated to clothing ecology
29
2024
-
08
What is alkali reduction? After reading it, you will understand!
The fiber wall of C-shaped fibers becomes significantly thinner, and the middle pores become significantly larger
Author:
Alkali reduction is the treatment of polyester fabrics in high temperature and concentrated caustic soda. After the surface of polyester is etched by alkali, the weight is reduced, the fiber diameter becomes thinner, the surface forms pits, the shear stiffness of fibers decreases, the aurora of polyester fibers is eliminated, and the gaps at the interweaving points of the fabric are increased, making the fabric feel soft and glossy, and improving its moisture absorption and sweat wicking properties.
Alkali reduction principle
Alkali reduction treatment is the process of treating polyester fabrics in high temperature and concentrated caustic soda solution. Polyester fibers are hydrolyzed and broken by the ester bonds of the polyester molecular chains on the fiber surface in sodium hydroxide aqueous solution, continuously forming hydrolysis products with different degrees of polymerization, ultimately forming water-soluble sodium phthalate and ethylene glycol.
Alkali plays a dual role: (1) it catalyzes hydrolysis; (2) Neutralization and hydrolysis of carboxylic acids
Changes in Polyester Alkali Reduction Treatment
The impact on fiber structure
After alkali reduction treatment, the surface of polyester fibers appears uneven, eliminating the aurora of polyester silk fabrics and making the luster softer; At the same time, alkali reduction treatment significantly reduces the bending and shear characteristics of polyester fabrics, causing fibers to become finer and softer. The interweaving points of the fabric are prone to looseness, eliminating the original smooth and stiff feeling of the fabric, making it soft, smooth, and elastic, with a style similar to real silk.
At lower alkali reduction, the fiber surface undergoes roughening and etching, resulting in the formation of pits on the fiber surface. With the increase of alkali reduction, the fibers will become finer, resulting in an increase in the specific surface area of the fibers and an increase in the surface area per unit mass.
The fiber wall of C-shaped fibers becomes significantly thinner, and the middle pores become significantly larger, accompanied by splitting phenomenon; Hollow fibers exhibit an increase in mesopores
The impact on fabric properties
The influence of 1 on the mechanical properties of fabrics
After alkali reduction treatment, the properties of polyester fabrics undergo significant changes. From the table, it can be seen that as the reduction rate increases, the fracture strength and fracture energy decrease. This is because after alkali reduction treatment, the fibers of polyester fabric become finer, and concave holes are formed on the fiber surface, causing stress concentration and a decrease in fracture strength and fracture energy. As the reduction rate increases, the elongation at break and Young's modulus of polyester fabric show a relationship of first increasing and then decreasing.
Key words:
Related news
4th Floor, No. 16-2, Wangwanghai Road, Xiamen Software Park 2
