CH141560A - Process for the production of viscose. - Google Patents

Description

  

  Process for the production of viscose. Structures made of viscose, such as artificial threads, ribbons, films, artificial R, osshaur and the like, are severely impaired in their appearance and in their chemical and physical properties by a content of heavy metal compounds, for example compounds of iron, copper, etc. especially if the heavy metal compounds are not evenly distributed in the viscose.

   In practice, it is very difficult to make viscose free of heavy metal compounds, since in the course of the production process there are extraordinarily many possibilities for letting such substances get into the viscose. For example, this can happen when water containing iron is used or when the chemicals used are contaminated by iron, copper or similar metal compounds, or when apparatuses are used that release heavy metal compounds when they are used.

   In large companies, you will have to reckon with the fact that viscose containing more or less metal salt will be processed. The content of heavy metal compounds gives the structures made from viscose an unsightly appearance after coabelling and can also cause streakiness, blotchiness or other irregularities.

   A content of heavy metal compounds is also capable of largely changing the colorability of the structures by changing the chemical or physical nature of the structures.



  It has now been found that such deteriorations in quality can be avoided in part if the viscose is added during its production or before processing such acids or their alkali salts, which are capable of forming easily soluble compounds with heavy metal salts. Osalic acid or organic ogyic acids such as citric, tartaric and lactic acid, etc .; Salts of these acids, in particular their alkali metal salts, are also expediently used. It can be added to the viscose in any desired manner.

   For example, when the cellulose xanthogenate, the dissolving lye or the water are dissolved, the desired amount of alkali metal salt of the oxalic acid or the organic oxyacids can be added. Taking into account the neutralization process, free oxalic acid or the mentioned oxy acids can also be used; It is also possible to add the additives in the finished viscose.

    Concentrations of 1 to 10 grams of oxalic acid or organic oxy acids per liter of viscose have proven to be useful; Depending on the technical requirements, a little more or less can be used.



  According to the process described, a viscose is obtained from which structures can be produced. Which show a clear and light shade and a uniform appearance. Irregularities in the colorability of the structures, insofar as they occur: caused by the presence of heavy metal compounds, are completely or almost completely avoided when using a product according to the invention, as tests have shown.

    <I> Examples: </I> 1. 5 grams of sodium oxalate per 1 liter of the viscose to be produced are dissolved in the water used to dissolve the cellulose xanthogenate.



       @. A concentrated solution of 10 grams of potassium oxalate is stirred into 1 liter of viscose.



  3. 5 g Seignettesa.lz are dissolved in 1 liter of viscose while stirring.



  The further treatment of the viscose takes place in the usual way in all cases.

 

Claims (1)

PATENT CLAIM: Process for the production of viscose, characterized in that the viscose is given an addition of acids or their alkali salts which are capable of forming easily soluble compounds with heavy metal salts. SUBClaims: 1 .. Method according to patent claim, characterized in that the acid used is oxalic acid. 2. The method according to claim, characterized in that the acids used are organic oxy acids. 3. Method according to patent claim, characterized in that the acids or their alkali salts are added to the substances used for the preparation of viscose.