What Are The Influencing Factors of Alkali Reduction?

The degree of alkali reduction treatment is generally expressed by the reduction rate.

1. Type and concentration of alkali agent

The ability of organic bases to hydrolyze ester bonds is less than that of inorganic bases, but it does great damage to fiber strength.

Inorganic base: KOH>NaOH>sodium carbonate

As the concentration increases, the reduction rate increases

The larger the specific surface area of the fiber, the greater the weight loss rate.

2. Alkali reduction accelerator

Cationic surfactants are often used to promote the reaction of alkali on polyester.

Promote the transfer of OH- in the solution and enrich it on the fiber surface

3. Influence of processing temperature

The temperature is lower than the glass transition temperature, and the reaction can only occur on the outermost surface of the fiber

When the temperature is higher than the glass transition temperature, the reaction can occur in a certain depth area

As the temperature increases, not only does the rate increase, but the hydrolysis reaction becomes violent and the alkali consumption is relatively high.

4. Influence of processing time

On the premise of ensuring a certain production efficiency, lower temperature, thicker alkali solution and longer time should be used for volume reduction treatment.

5. Liquor ratio

The liquor ratio is small and uneven weight reduction is likely to occur.

6. Influence of fiber morphology and structure

It is difficult for the sodium hydroxide solution to penetrate into the fiber, and the reaction is mainly concentrated on the surface of the fiber.

The finer the fiber, the larger the specific surface area and the faster the reaction.

Fibers with smooth and round cross-sections are more resistant to alkali than fibers with special-shaped fiber cross-sections such as matte and multi-leaf shapes.

New synthetic fibers are much faster than conventional fibers, but react less uniformly