SU61906A1 - The method of obtaining secondary cellulose acetate - Google Patents

Description

v oBpeMCii.ibic c: iGco6b no.iyMCiins aceticl alkallose have a number of disadvantagesTBtMiHbix, of which it is worth mentioning dopedly the process of ripening nrn for burning (adhesion) (acetone) acetone in the pulp. Under natural conditions, the ripening process is from up to 60 hours.

In those cases; x. when it is necessary (try ntskoatsetnlirovannuyu nellu.yuzu with soda 1zhne; 46. svy-siuy acetic acid, have H1, her systsalnuyu g value, the process is lengthened to 80 --- 120 hours. At the same time, the viscosity of acetals pulping decreases sharply, indicating a significant destruction of the product.

The duration of c (): the acetylcellulose cutter forces the acetylnrowine process and further processing of the obtained acetate ii to several stages (acetylated, saponified and matured, sedimentation, etc., with a large number of apnarates (acetyls, chapes for maturation, precipitate, sediment, precipitate, sediment, etc.). etc.). Zgo 1, treats for itself the cost of labor and energy, accelerated depreciation of equipment, and contributes to the creation of anti-hygienic equipment and production.

Offer the method makes it possible to reduce the d / shta.nost, the process of saponification and the ripening of the anetium. I have combined several onerations (acetylclic acid: saponification, maturation, and precipitation), in order to implement them in the same form (acetyl torus). Especially important is the proposed method to have for obtaining low-acetylated cellulose, so Kaic ipii does not observe a sharp drop in the viscosity of the product.

No. 61906-2

The essence of the method is that the syrup, along with the usual scrubbing mixture, diluted with acetic acid or a mixture of water and sulfuric acid, is added to the syrup of the bony active substance that provides the fastest and most intimate sonric of the nervous cellulose acetate. (triacetate) with water, thereby accelerating the saponification process and all colloidal natroceses associated with it.

It is known to use organic compounds containing hydroxyl granules as additives to the saponification mixture in the process of obtaining secondary cellulose acetate from the primary. The reason for the proposed method is that hydrophilic, having surface-active properties, hydrocellulose substances of varying degree of degradation, oxycetotulose, hydrate, pulp or pulverized cellulose are used as additives.

Otav1la. With acetate tse.tlyu.yuzy in small to. The properties of hydrocellulose and; e- may interfere with the synthesis of the product produced for technical purposes. In the production of plastics G1, the cellulose serves as an active ionopolymer and increases the mechanical yield of plastics produced. When producing artificial fiber or films, the hydrocellulose can be filtered during the process without incurring additional costs, since cellulose acetate solutions are usually subjected to multiple filming before spraying or before casting to a film machine.

In addition to artificial administration, 1-hydrocello pulp can be obtained by the acetylation process itself, if instead of the usual 250-300%, 200-170% acetic anhydride (by weight of cellulose) is taken. The hydrocellulose produced along with primary acetate accelerates the saponification and maturation process several times.

An example of the preparation of normolpi secondary acetate is cellulose. Cotton or wood pulp is subjected to conventional ocetylation (per 100 parts by weight of linter take 225-300 parts by weight of acetic anhydride, 400 parts of acetic acid, 12-25 parts of sulfuric acid or the corresponding amount of another catalyst) at a temperature of 30-35. Then, a quantity of water or dilute acetic acid is introduced into the clear syrup of primary cellulose acetate so that the final concentration of acetic acid in the solution does not exceed 95-97%. Then, at the same temperature and with stirring, 5% hydrocellulose with a copper number of 10-15 is added. Stirring is carried out within 1-2 hours. During this time, the developmental and ripening period ends. The resulting secondary cellulose acetate with a content of 55-57% bound acetic acid is precipitated with conventional puff (water).

Before precipitating the hydrochloride. Loza. It is possible from 11.

Production Example of Low Acetylcrow Cellulose with 46-50% Associated Acetic Acid Content. The saponification and ripening process is carried out under conditions similar to those described, but in the continuation of 6-8 hours or for 2-4 hours, but in the presence of 20-30%. hydrochloride.

Finally, the acylation can be carried out with a deficiency of acetic anhydride (200-170% by weight of cellulose); however, the maturation hydrocellulose is not additionally introduced.

The method of producing secondary acetate of cellulose by saponification of primary acetate with organic compounds containing hydrolysilic groups in the presence of a conventional saponification mixture, characterized in that, in order to accelerate the saponification process, hydrocellulose, hydroxycellulose, cellulose cellulose, or pulp hydrate are added to a conventional saponification mixture, hydrochloride, cellulose hydrate, cellulose cellulose, or pulp hydrochloride. cellulose in an amount up to 30% by weight of acetylcellulose.

.NO 61906

Subject invention