DE810167C - Process for refining artificial structures, such as threads or, in particular, rayon from cellulose hydrate - Google Patents

Description

Process for refining artificial structures, such as threads or in particular Cellulose, from cellulose hydrate It is already known that cellulose and cellulose hydrate, like rayon and rayon, with a fatty acid anhydride at an elevated temperature using alkali salts of weak acids as a catalyst to a large extent to esterify. This esterification makes the properties of the starting fiber strong changed, e.g. reserve against substantive dyes, insolubility in organic solvents, higher ironing fastness, change in handle and appearance etc., achieved.

After the known processes one can produce largely esterified products get, when using acetic anhydride z. B. up to the stage of 21/2 acetate.

A major disadvantage of the largely esterified, z. B. acetylated eti It is a good thing that the acetate celluloses obtained are not resistant to laundry, So against soap and soda, what results in a significant increase in swelling of the originally heavily swollen goods. When boiled for 1/2 to 1 hour with a solution of 5 g of soap and 3 g of soda per liter, z. B. the source value a rayon acetylated according to known methods from 37% to 500/0. At a repeated washing results in a further deterioration in the swelling value. Even Goods that are even more esterified and have a swelling value of only 25% are subject to this this harmful nuisance. In and of itself there is the fact that with Cooking with soap and soda saponifies the cellulose acetate and thus increases the swelling value occurs, not surprisingly, for use in the laundry sector, however, where it is important is placed that the swelling of the fiber in the washing process in the size of the Cotton swell or remains below, however, such a product is almost unusable, at least Can only be used to a very limited extent.

The surprising finding has now been made that it canceled n is, to a large extent, esterified commodity, which has a strong reduction in swelling, namely decreasing up to 1 / s of the initial swelling, but against hot soap-soda solution is stable to achieve that the pretreated in a very specific way Cellulose is post-treated with aromatic acid anhydrides. The pre-treatment happens in such a way that the cellulose in concentrated solutions of alkali salts dipped in salicylic acid and then dried well. Although the The new type of process is also an esterification of cellulose cellulose esters formed after it nevertheless counteracts alkaline saponification Soap and soda surprisingly without any practical impairment of the swelling value resistant. Goods made from it can therefore be used safely in the important laundry sector are used, the favorable ones achieved by the strong reduction in the swelling value Properties are fully retained: n.

Aromatic ones have proven to be particularly advantageous in use Acid anhydrides have been shown to contain an aliphatic group in the molecule, e.g., benzoic acid anhydride, cinnamic acid anhydride, and the like. These substances result in an extremely strong reduction in the swelling value down to 1 / s des Initial value. Nevertheless, the goods refined with it are constantly swelling against hot soap or soda solutions. The simple aromatic acid anhydrides, such as benzoic anhydride and cinnamic anhydride, do not cause the oil to swell as much. The output source value is reduced by about 1 / a, but this is also de-swelling Resistant to soap and soda. The opposite to those with aliphatic acid anhydrides achieved advantage is obvious. The following may be given as working examples are: Example i 60o g moist, never dried, unavivated viscose rayon with about 70% water content is immersed in a 50% sodium salicylate solution for 30 minutes submerged, whereupon it is thrown off to a weight of 920 g. The pre-impregnated one Goods are kept for 90 minutes at 90 ° with good air circulation to a weight of 65 ° g dried. This is followed by an after-treatment in a bath of 6.6 1 chlorobenzene, in which 1.5 kg of benzoic acid anhydride are dissolved, for 120 minutes ioo ° instead. It is spun off with acetone, then washed with water, again spun off and dried normally. After conditioning, this is The weight of the goods is 435 g, so it has increased considerably. The water retention capacity is 230/0 compared to 74% of the untreated goods. In addition, the goods show water-repellent properties Properties; she floats on water. After one hour of soaking, the swelling value was up 24.8, so practically unchanged.

Example 2 1509 moist viscose staple viscose as in example i is immersed for 15 minutes in 2.5 l of a 40 ° saturated sodium salicylate solution and spun off to 233 g. The rayon, dried for 105 minutes at 90 ° to a weight of 165 g, is then treated for 60 minutes at 90 ° in a liquor of 1.7 liters of chlorobenzene and 350 g of benzoic anhydride and worked up as above. The rayon obtained has a water retention capacity of 51.70 / 0. After one hour of boiling soaping with a solution of 5 g of soap and 3 g of soda per liter, the swelling value was 52.9%, i.e. it remained practically the same.

Example 3 Treatment of contrast produced by the Patent 7o6 870, already dried cell wool with a 5o °! Pc potassium acetate before, dried and treated according to in Essigsäureanllydrid, one obtains a swelling value of 37.3% (untreated 86%). If the staple viscose soaked in this way is soaked for one hour at a boiling point with a solution of 5 g of soap and 3 g of soda, and then again the original value is determined, then the result is that the goods have suffered greatly in terms of their swelling value and has also become very uneven. The swelling values are between 45 and 54%.

Claims (1)

PATENT CLAIM: Process for refining artificial structures, such as threads or, in particular, rayon from cellulose hydrate, characterized in that the freshly produced, washed, post-treated, but not yet dried, unavailable threads are pretreated with a concentrated alkali salicylate solution, and after the excess is removed, the goods are dried and now an aromatic one Brings acid anhydride to act at an elevated temperature, followed by washing with an organic solvent such as acetone and the like, followed by washing with water and then drying.