SU933844A1 - Method of saponification of acetate fibre - Google Patents

Description

(5) METHOD FOR WASHING ACETATE FIBER

I

The invention relates to chemical technology of silk materials. Namely, to the technology of saponification of acetate fiber.

Acetate fibers are scrubbed to reduce their electrified and to obtain from them cellulose hydrate,

A known method of saponification of acetate fibers by treating it with an aqueous solution of alkali metal hydroxide flj.

The disadvantage of this method of saponification is the low speed of the process and polymer degradation. The latter process worsens the physicomechanical properties of the fiber. The saponification rate increases with increasing alkali concentration and temperature. However, at the same time, the rate of destruction increases so much that the fiber becomes unsuitable for use.

Closest to the invention is a method of saponifying acetate fiber, according to which the fiber is treated with an aqueous solution containing sodium phosphate and sodium hydrogen phosphate. The phosphate concentration is U-38 g / l (1.4-3.6%), and the hydrogen phosphate is 1.4-3.8 g / l (0.14-0.36). The temperature of the wash solution does not exceed 70-80 C 2,

to

The disadvantage of this method is the low speed of the process. The complete saponification of acetate fibers is achieved in 30-65 minutes. Therefore, this method is applied only for

15 partially saponified fiber and in a batch process. This method is unsuitable for complete saponification of continuously moving fibers.

The purpose of the invention is to intensify

Claims (2)

30 process. The delivered chain is achieved by the fact that during the saponification of the acetate fiber by treating it with an aqueous solution with a sodium phosphate thief at an elevated temperature, the treatment is carried out with (40-48)% sodium phosphate solution at 100. 0.1-1.6% by weight of sodium hydroxide can be additionally added to the treatment solution in order to speed up the saponification process. Under these conditions, the fiber is practically not hydrolyzed and completely saponified in 25 minutes. Example 1. Acetate fiber, having a strength of 14 g / tex, is treated at a temperature with a solution containing 40.5% sodium phosphate. The fiber is completely washed for 5 minutes. The cellulose hydrate fiber obtained has a strength of 24 gf / tex and an elongation of 20. Example 2 Acetate fiber having a strength of 14 gf / tex is treated at a temperature of 125 ° C {solution containing 48% sodium phosphate. The fiber is completely saponified for 2 minutes. The resulting cellulose hydrate has a strength of 22 gf / tex and an elongation of 19%. Example 3. Acetate fiber having a strength of 15 gf / tex is treated at 100 ° C with a solution containing 40.5% sodium phosphate and 1% sodium hydroxide. The fiber is completely saponified for 1.5 m. The hydrated cellulose fiber obtained has a strength of 24 gf / tex and an elongation of 18%. EXAMPLE 4 Acetate fiber having a strength of 15 g / tex is treated at a temperature of 6 ° C with a solution containing 44% sodium phosphate and 1.6% sodium hydroxide. The fiber is completely saponified for 1.5 minutes. The obtained hydrate is roznu rolokno has a strength of 24 rc / teKC and an elongation of 21%. Example 5. Acetate fiber having a strength of 14 gf / tex is treated at a temperature with a solution containing 40% sodium phosphate p1 0.1% sodium hydroxide. The fiber is completely saponified for 4 minutes. The resulting cellulose hydrate has a strength of 23.5 gf / tex and an elongation of 20%. Thus, the proposed method makes it possible to speed up the saponification process by a factor of 20 while at the same time producing fibers with high physical and mechanical properties. This allows for the saponification of acetate fibers in a continuous production process using automation, which increases productivity. Claim 1. Method for saponizing acetate fiber by treating it with an aqueous solution of sodium phosphate at elevated temperature, characterized in that, in order to intensify the process, the treatment is carried out with (4048)% phosphate solution. Sodium at 100-125 0. 2. Method Pop. 1, characterized in that the treatment is carried out with a solution containing additionally 0.1-1.6% by weight of sodium hydroxide. Sources of information taken into account in the examination 1. Mankriff R.U. Chemical fiber. M., Easy Industri, 1964, p. 207-210. 2. US patent number 2206946, cl. 8-130, pub. 1940 (prototype).