JPS6134275A - Alkali treatment of cellulose acetate fiber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This is a method for obtaining a new silk-like fiber, and it is possible to easily obtain a new rayon-like yarn with drapability. It is also possible to obtain a new rayon-like yarn with a special cross section from cellulose acetate yarn with a special cross section, which is not necessary and is relatively easy to obtain.

[Conventional technology]

The saponification of steam-stretched cellulose acetate to obtain rayon is well known, having been commercialized by Secinise with 7 ortiza/points.

It is also known that a strong yarn can be obtained by saponifying the stretched cellulose acetate with a strong alkaline aqueous solution containing an inorganic substance while it is being stretched or until the stretched cellulose acetate is nearly completely saponified. Kusengaku Shi, 7,505 (1951), etc. In addition, inorganic salts may slow down the rate of full alkali saponification.
Also known as 〈Censics Journal, 21.98 (1965)
On the other hand, it is also disclosed in JP-A-54-96112 that special sheath/core fibers can be obtained by surface saponification.

From these prior art techniques, it is known that cellulose acetate obtained by saponifying cellulose acetate to a high degree without stretching and under no tension has a problem in that the cellulose acetate is subject to significant shrinkage and strength loss.

[Problem that the invention seeks to solve]

In the present invention, cellulose acetate can be directly stretched to 10% without stretching.
When performing alkali treatment that causes a weight loss of more than % and obtain a new type of rayon-like yarn with a soft hand and drapability, a strong alkali is used to speed up the alkali treatment and shrinkage hardening is performed. This is an attempt to eliminate the problem of making money.

[Means to resolve the problem]

The present invention is an alkali treatment method for cellulose acetate fibers, the entire gist of which is to perform alkali treatment on cellulose acetate fibers with an aqueous solution containing a strong alkali and an inorganic salt, resulting in a weight loss of 10% or more.

The cellulose acetate fiber of the present invention has an acetylation degree of 50
~62% fibers and mixtures thereof. Strong alkali refers to an alkali such as caustic soda or caustic potash that exhibits a pH of approximately 15 in a 0.1N aqueous solution.

The weight loss of 10% or more is mostly due to weight loss due to elimination of acetyl groups, but also includes weight loss due to cellulose dissolving in alkali after complete elimination of 7 cetyl groups. 10
If the weight decreases by less than %, it is difficult to obtain a rayon-like drapey feel.

The inorganic salt used in the present invention is preferably one that is water-soluble and has high water solubility, such as sodium citric acid, sodium tartrate, sodium acetate, sodium sulfate, and potassium acetate.

゛ The alkali treatment in the present invention refers to immersing a thread or fabric made of cellulose acetate fibers in an aqueous solution containing a strong alkali and an inorganic salt, and treating the yarn or fabric at a predetermined temperature (from room temperature to 1000°C).
(temperature up to 100%)
This refers to dissolving the gas.

Cellulose acetate that has been stretched to a large extent is strong, but it is not possible to obtain a silk-like, drapey yarn, and stretching several times as much during alkali treatment is not good in terms of texture. It is desirable that the thread be stretched and stretched to such an extent that it does not cause undesirable stretching effects, such as smooth running of the thread through the alkaline bath or wrinkles in the fabric.

The present invention 8A enables alkaline saponification without shrinkage hardening by adding an inorganic salt to a strong alkali and treating cellulose acetate with an alkali.

〔Example〕

The present invention will be specifically explained below using examples.

Example 1 A plain woven fabric of 751/21f ply yarn of a ring (heat-resistant diacetate acetate degree 55.2% manufactured by Mitsubishi Acetate Co., Ltd.) was treated with tripolyphosphoric acid and a nonionic activator, and after desizing and scouring for 10 minutes at 70CX, 180CX After presetting for 30 seconds, in a bath of caustic soda 40 I/J sodium acetate 12011/-13,
As a result of treatment with 80CX for 2 minutes and neutralization drying, the weight loss rate was 39
A rayon-like fabric with a silk-like luster and great drapability was obtained.

For comparison, in the case of a similar product without adding sodium acetate, acetate dissolves in alkali and shrinks and hardens.
It was in the form of a film and was not available.

Example 2 756 of the ring (described above). /21r bright yarn and Soluna (polyester fiber manufactured by Mitsubishi Rayon) 506/4
8r semi-dull yarn mixed with strong twist □ Boil the fabric in a bath of caustic soda 40I/noacetic acid soda L5 Q, I/4×
The weight loss rate of the ring treated for 40 minutes was 48%, and the weight loss of the polyester was 23%, yielding a rayon-like polynystere mixed fiber strong twist fabric with silk-like luster and great drapability.

〔Effect of the invention〕

If the weight of the yarn is reduced to near complete saponification through this treatment, even if it is further treated with a strong alkali alone, the cellulose will dissolve and the weight will be reduced due to the alkali, but shrinkage and hardening will not occur, so polyester fibers etc. If the present invention is applied to cellulose acetate yarn fibers mixed with polyester, there is an effect that shrinkage and hardening will not occur even if the polyester is reduced.

Additionally, in cellulose acetate-based fibers mixed with polyester etc., it is possible to obtain rayon-like saponified acetate with drapability and at the same time reduce the amount of polyester with alkali. It is also a unique technology for producing a saponified acetate blend with a certain rayon-like appearance in one step.

Claims (1)

[Claims] 1. A method for alkali treatment of cellulose acetate fibers, which comprises performing an alkali treatment of cellulose acetate fibers with an aqueous solution containing a strong alkali and an inorganic salt, resulting in a weight loss of 10% or more.