US1399587A - Process of precipitating viscose - Google Patents

Description

FRANZ STETMMTG, 01F HANOVER, GERNT.

PRU'CESS T PRECTPTTAG VISCOSE.

teaser.

Specification of Letters Patent.

Patented Dec. 0, ffidf.

lt'o Drawing. tlrtginal application filed June it, 1913, serial No. 773,32t. Divider]. and this application filed August 112, 1916 ficrial l lo. 114L661.

(GRANTED UNDER THE JPRO VIEIMIDNS 01E THE ACT 0T lltlflR'Ull-l 3, 1921, M STAT. L, 1313.)

To all whom it may concern:

- Hanover, Germany, have invented certain new and useful Improvements in Processes of' Precipitating Viscose, (for which T have filed applications in Germany, Feb. 15, 1913,

flit lift L which is produced viscose.

and Great Britain May 10, 1913,) of which the following is a specification.

This invention relates to the production of cellulose compounds suitable for use as films or filaments for fabrics from the material known commercially as viscose from a solution of cellu-- lose as described in T]. S. Patent No. 520770 dated June 5th, 1894.

lln the manufacture of threads suitable.

for the manufacture of yarns and fabrics from viscose, preference has been given to setting baths consisting of acidulated solutions. This is readily understood in view of the fact that viscose contains a cellulose derivative which is soluble in an alkaline solution, that is to say, it cannot be precipitated by being acted upon by an alkali.

Nevertheless it would be, advantageous to employ a setting bath with an alkaline action for cellulose derivatives produced from ft is known that viscose may be coagulated by the aid of a concentrated solution of a neutral salt, (Patent .No, 520770 of 189i.) This coagulating action cannot, however, be employed commercially in a satisfactory manner to produce, derivatives. of cellulose with continuous operation of the process owing}; to the fact that the increasing quantity of alkali in-the bath soon renders its presence felt by preventing the cosomewhat unexpected as in'view of the experience gained with the process described in T]. S. Patent No. 622087 dated 28th March, 1899, it would appear that only a' concentrated solution (say to 40%) of ammonium sulfate would provide an ef-' bered that it is impossible with ordinary commercial, viscose to precipitate a single filament with a ten percent. ordinary solut on of ammonium sulfate.

Tn making the setting bath, T preferably prepare a solution containing ammonium sulfate, and a neutral salt such as sodium sulfate (Glaubers salt), magnesium chlorid, calcium-ohlorid, or sodium chlorid. Tn place of such neutralsalts, T can also employ such a material as a tertiary alcohol, e. g. glycerin.

The quantity of ammonium salt to be added to the neutral salt solution such as brine may be varied within narrow limits only. The amount depends to a great extent u on the kind of product which it is desire to produce and would require to be diflerent in the case of coarse fibers, say imitation horse hair and in the case of fine fibers such as are necessary. for artificial silk. The bestmy improved precipitating bath some third I substance, (such as an oxidizing agent or a reducing salt) just as in the case of acid baths. These agents, which may be sugar, arsenous compounds or the like, (which act as reducing agents) or sodium hypochlorite (which acts as an oxidizing agent) have the effect of adding brilliancy to the fibers. It is also quite practical to add metal salts to the precipitating bath as is known in another process, which salts form insoluble sulfids with the alkaline sulfid. This latter method is not however necessary as experience shows that with the herein described new bath there is no tendency of the fibers to become sticky.

The filaments or films may he squirted in any suitable way into the precipitating bath and on leaving this they are wound prefer.

ably on a drum which rotates in brine. in. this way the cellulose derivatives are washed,

. organic substances are'added for known purposes to affect the product and it has been found that with the invention such substances may be used with similar results as obtained in the known coagulating solutions.

In all cases I prefer to employ a setting bath containing one or more of the neutral salts above referred to (NaCl, Na SO MgCl CaCl etc.), which compounds are generically referred to as a neutral salt of an alkali-forming metal and also containing a relatively small amount of an ammonium salt, capable of existing in solution with the neutral salt (one or more of such) employed. Other agents for the productlon of special effects may be added if desired. The bath will preferably be substantially saturated with the neutral salt employed.

I call particular attention to the use of a solution made up by dissolving in thirty parts of water, sixty parts of Glaubers salt (Na SO 10H O) and ten parts of ammoniumesulfate. Such a bath has given excellent results, and is preferably maintained at a temperature of 35 to C.

Another bath which I find givesexcellent results is a solution containing 19 parts Nacl 12.5 pants Cacl 10 parts NH |Cl,

and 48.5 parts water. Another bath giving excellent results is a solution of 45 parts CaCl 10 parts NH Cl; and 45 parts of water. Magnesium chlorid in various mixtures gives good results.

Regarding the ammonium salt, this may be ammonium sulfay 'or ammonium chlorid, and I find that a mixture of these two, also gives good results.

I do not claim the setting baths, per se, in the present case, since said baths form the subject matter of -my copending application 773,324 of which the present case is a division.

What I claim is 1. Process for treating cellulose products for the manufacture of films and filaments, which consistsin squirting the viscose into an acid-free concentrated solution of a neutral salt also containing only a small percentage of an ammonium salt.

2. A process of treating viscose which comprises subjecting the same to the action of an acid-free bath containing a neutral salt and about ten per cent. of ammonium sulfate.

'sulfate and containing a small 3. Aprocess of treating viscose which consists in squirting the same into an acidfree solution containing ammonium sulfate and sodium sulfate.

4. A process for treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution-substantially saturated with a neutral salt, and containing a small percentage only of an ammonium salt.

5. A process of treating viscose which comprising subjecting the same to the action'of an acid-free setting bath comprising a solution substantially saturated with a neutral salt, and containing not over 10% of an ammonium salt.

6. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution substantially saturated with a neutral salt, and containing not over 10% of ammonium sulfate.

7. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a. solution substantially saturated with sodium percentage only of an ammonium salt.

8. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution substantially saturated with sodium sufate and containing not over 10% of an ammonium salt.

9. A process of treating viscose whichcomprises subjecting the same to the action of an acid-free settin bath comprisin a solution substantially saturated with sodium sulfate and containing not over 10% of an ammonium sulfate.

10. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprisin a solution substantially saturated with sodium sulfate and containing an ammonium salt.

11. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution substantially saturated with a nontral salt of an alkali forming metal and COiltiLlIllIlg not over 10% of an ammonium sa t.-

12. A process of treating viscose which comprises subjecting thesame to the action of an acid-free setting bath comprising a solution substantially saturated with a neutral salt ofan alkali forming metal and containing a small percentage of an ammonium salt.

13. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution substantially saturated with a neutral salt of an alkali forming metal and containing ammonium sulfate.

meats? 14L A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution substantially saturated with sodium sulfate and containing a small percentage of ammonium sulfate.

15. A process of treating viscose which comprises subjecting the same to the action of an acid-free setting bath comprising a solution substantially saturated with sodium 10 sulfate and containing not over 10% of an ammonium sulfate.

In testimony whereof ll afiix my signature in the presence of two Witnesses.

- FRANZ STEIMMIG. Witnesses:

N. N. BEHNE, R. MICHAELS.