DE553839C - Process for the production of rayon by spinning viscose solutions in baeder - Google Patents

Description

Process for the production of rayon by spinning viscose solutions in felling baths The invention relates to a method for producing artificial silk of high tensile strength made of viscose and enables artificial threads, ribbons or to obtain films, their tensile strength in wet as well as in dry state is exceptionally large.

It has been found that one can obtain a product of great tensile strength can be obtained in the wet as well as in the dry state if one according to the invention a spinning bath used, -which at least 30 sulfonic acids of aromatic hydrocarbons contains.

It has already been proposed to add 0.5 to 10% benzenesulfonic acids to the spinning bath to allow the draw spinning process for viscose (Swiss patent 94 42o). In exercising this proposal it has been found that the tensile strength of the product obtained practically with that of the one without the above-mentioned additive product received.

In addition, small amounts (6 to 8%) of sulfonic acids of aliphatic hydrocarbons were added to the spinning bath in order to be able to spin unripe viscose in this way (Patent 462: 217), while 12 to 15% of a condensation product of formaldehyde was also used for the same purpose and phenol sulfonic acids were added to the spinning bath (Patent 458 91o). Finally, the addition of sulfonic acids of aromatic, aliphatic or hydroaromatic substances to the spinning bath is known, the total acid content not being more than 18 % (French patent 578 159 and Dutch patent 851t). According to the invention, the amount of additive should be at least 30.degree. 1o if at least the particularly favorable results which form the subject of the invention are to be obtained.

The tensile strength of the rayon obtained according to the invention is more than 2, even up to 5 g per denier, a tensile strength which could otherwise only be achieved using a higher acid concentration. This high acid concentration, which has already been used to increase the tensile strength when spinning a cellulose solution in copper oxide ammonia (patent 125 310) and for spinning nitrocellulose (patent 339 011), results in certain values when used according to Viscosev (British patent 27q.521) Trouble. It is probably due to this situation that the originally proposed method, namely treating the viscose threads during manufacture by means of an acid with a parchmentizing effect (French patent 313 q.64), has not found any use in practice. It is also known to spin viscose in concentrated glycerol sulfuric acid (5010 H.S04) or 80% methyl or ethyl sulfuric acid (French patent 369957) , which actually results in a greater tensile strength. The following example serves to illustrate the invention: 1 kg of cellulose is soaked in sodium hydroxide of 180/1 for 2 hours; pressed until the weight is 3.3 kg, then ground and finally matured for 2 days. The sodium cellulose obtained in this way is xanthogenized by means of 300 cm 'carbon disulfide at 22 to 24 ° C. for 3 hours. The yanthate obtained in this way is dissolved in a sodium hydroxide solution in such a ratio that the solution obtained contains about 7% cellulose and 5 to C% total potassium. After it has dissolved, it is filtered and spun in a bath with 40 to 70% benzene monosulfonic acid. During the spinning, tension is exerted on the thread, which tension is obtained by means of a thread guide which is mounted in the spinning bath in the spinning bath 30 to 60 cm from the spinneret.

The strongly acidic thread is required if it is wound up in a spinning pot becomes, only one wash with water to produce a thread that is only approximately Contains 2% titratable acid. Instead of water you can also use diluted acid or use a saline solution to wash out.

The product obtained has a tensile strength of 2 to 3 grams per denier when wet and from 4 to 5 grams per denier when dry. The stretch is 10 to 13 per cent and more, which elongation is considerably greater than that which is obtained with spinning baths with a high concentration of inorganic acids.

The viscose solution can first be allowed to mature in the normal way or use only a short maturation period. Instead of pure beuzol sulfonic acid the reaction mixture of benzene and rigid sulfuric acid can also be used, such as this is common in the art for the production of benzene monosulfonic acid, whereby the advantage is achieved that there is no separation of the products, which in this Reaction arise, needs to be carried out. You can also use other sulfonic acids, which are soluble in the spinning bath mixture, use, as well as z. B. Sulphonation Products the benzene homologue. In addition, you can use known additives in the spinning bath, like glucose, alcohol, etc.

The composition of the viscose as well as its maturity can be within further limits vary, although the best successes with poorly ripened viscose can be obtained, especially when xanthogenated with a little carbon disulfide.

Claims (1)

PATENT CLAIM: Process for the production of rayon by spinning of viscose solutions in precipitation baths, the sulfonic acids of aromatic hydrocarbons contain, characterized in that these spinning baths contain at least 30 ° @ o sulfonic acids contain aromatic hydrocarbons.