US1428246A - Process for producing spun material resembling wool, cotton, or chappe from viscose solutions - Google Patents

Description

Patented Sept. 5, 11922.

air so 51 "res PATE T OFFICE.

PAUL HERMANN MINCK, F PETECRSDORF, GERMANY, ASSIG-NOR, BY MESNE ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INCL, A. CORPORATION OF DELAWARE.

rnocnss FOR PRODUCING SPUN MATERIAL RESEMBLING WOOL, .oor'roN, on GHAP'P'E mom vrscosn SOLUTIONS.

No Drawing.

Application filed May 16, 1919. Serial No. 297,712.

. (GRANTED UNDER THE PROVISIONS 01 THE ACT-0F MARCH 3, 1921, 41 STAT. L, 1313.)

To all whom it.;may concern:

Be it known that I, PAUL HERMANN MINoK, a citizen of the free city of Hamburg, residing at Petersdorf, Riesengebirge,

Germany, have invented certain new and useful Improvements in Processes for Producing Spun Material Resembling Wool, Cotton, or Chappe, from Viscose Solutions (for which I have filed applications in Germany, principal Feb. 22, 1918-; 1st additional Mar. 27, 1918; 2d additional April 6, 1918; 3d additional Aug. 15, 1918; Austria, Sept. 5, 1918; Hungary, principal Dec.

5, 1918; 1st additional Dec. 5, 1918; 2d additional Dec. 18, 1918), ofwhich the followin is a specification.

%t is well known that in preparing viscose solutions for the manufacture of artificial to. a very thorough hydration by' means of T alkali lyes, as only after such treatment,

it will, under action of carbon bisulphide be converted in alkaline solution into a solution sufliciently thin and homogeneous I essary to obtain the proper degree of hydrav tion of the cellulose, and the viscose solution prepared from such hydrated cellulose before it ma must mature for at least another four days he spun. If spun immediately an abso utely dull, brittle yarn will be obtained, by the highl hydrated cellulose being precipitated in t e coagulating bath in a form so incapable of diffusing that the solvent agents contained in the yarn and violently decomposing therein, will likewise decompose the wall of the thread.

With a continued maturation of the solution the greater part of the caustic soda and carbon blsulphide is again separated from the molecule of the cellulose alkali Xanthogenate, so that it is then possible to undisturb'edly precipitate the cellulose hydrate by aid of suitable precipitating baths.

The whole process is very expensive and requires much time, asthe preparation of a solution suitable for being spun into artlficial silk will require about nine days, during whlch time certain temperatures have to be maintained, a very complicated plant is required for storing the material and lastly very complicated spinning baths have to be employed in spinning the solutlons. The cost of manufacture has, indeed, not played any important part in the manufacture of artificial silk, which may be considered as an article de luxe.

In searching to produce a wool-like spun material for which a great demand has arisen owing to the scarcity in wool and cotton the inventor proceeded from the assumption that the heretofore employed far reaching hydration of the cellulose is undesirableas only the strength is required and a high gloss is of no importance .if the product is to be. used as a substitute for the natural fibres or for the manufacture of films.

Practical research showed that there exists a suitable minimum in the hydration of the cellulose, at which the latter will, after being converted into the Xanthogenate, still be completely dissolved.

The novel feature of the present process consists in that a solid, soft and wool-like spun yarn is produced which may serve as a substitute for wool, cotton and chappe, and yarns made therefrom, in particular such yarns which have the moderate gloss of real silk. This object is obtained by subjecting, when a viscose solution is used, the cellulose employed for such solution before its treatment with carbon bisulphide and its solution, to a moderate hydration by means of caustic alkalies so that the threads will not assume the typical high gloss of artificial silk. Compared to'the latter the new product has the advantage of its being possible to make and spin it in a single day, whereas with the process for making artificial silk about nine days are required.

differs from the usual viscose solutions for 1 i the manufacture of artificial silk by having a small dispersity and a comparatively higher viscosity, which is about three times as high as the usual solutions.

The new spinni material which co tains the cellulose in solution in. a very slightly hydrated form may, contrary to the known viscose solutions, be spun immediately after its production, 'and will yield an extremelfi strong and soft yarn having a soft, woo ike gloss. This new result is owing to the peculiar condition of these solutions. The coagulation of the threads obtained frame-the highl viscous solutions proceeds much more slbwly, so that for this purpose spinning baths prepared from diluted mineral acids may be used, without theotherwise appearing destruction of the cellulosehydrate precipitated being observed. The combination of the xanthogenatewiththe cellulose molecule is, owlng to themoderate hydration,

probably weaker in the solution and the solvent agents can, in conse uence of the lesser dispersity of the disso ved' cellulose and the resulting higher difi'using capacity of the coagulating thread, more easily emerge from the latter before the same is completely solidified.

Example.

100 k0. cellulose are saturated'witli 18% soda lye and thereupon centrifuged until it contains only two parts (by .weight) of lye to 1 part of cellulose. The cellulose is then left onl for 12 hours approximately under the by rating action of the alkali, whereupon it is treated with kc. carbon bisulphide and is dissolved in about 1600 ko. 3% soda lye. The thus obtained spinning material may be immediately spun in a.12-15% sulphuric acid bath, and during this spinning it is of advantage to afi'ord the threads as long a travel through the bath as possible,

It has been further found that, particularly in well. opened cellulose this already greating reduced after-hydration of the pressed out alkali cellulose by a temporary action of moderate heat and air may be entirely omitted and that in such case the yarn will become still more woollike and stronger. v

This represents a twofold improvement both as regards the economy of the process and the quality of thefinal product.

Also the solutions obtained from such slightly hydrated cellulose. (by a brief dipping merely). may be immediately spun in baths prepared from mineralacids and do not require a maturin period of several days. The concentration and len h of the spinning baths may have eonsi erably messes wider limits as the coagulating roperties of the spun threads will, with ecreasing hydration of the cellulose become more and more-favorable.

It has been further observed that the uality of the yarn is improved by reucingthe quantityof carbon bisulphide coming into action and by increasing the cellulose contents'of the spinnin solutions. It may be here mentioned that t e cellulose may be dipped at the ordinary temperature, but that for the dissolutionof the cellulose a somewhat lower temperature has to. be maintained, which is preferably maintained at the same de ee up to the spinning operation, as according to the feature of the novel process the after maturing, which is required for the'production of artificial silk threads, is completely omitted.

- Ema/mph.

freed by centrifuging or pressing from the" surplus soda. lye until the cellulose contains not more than two parts (by weight) of lye to onepart of cellulose. The thus obtained alkali cellulose is thereupon carded and immediatel treated with about 35% carbon bisulphlde (reckoned to 'the dry cellulose) without exposing the latter previously to an otherwise usual maturation in closed vessels at higher temperatures. The xanthogenate is then dissolved in about 1200 k0. 4% soda lyeat a temperature of less than 15 cent, whereupon the solution may be immediately spun in a mineral acid bath. The solution should be stored at-temperatures below 15 cent. as otherwise the maturing of the viscose, which ought to be avoided, will commence.

It has been found that a very small excess of soda lye beyond two parts of the cellulose weight will very' unfavorably influence the quality of the viscose solution and the yarn spun-therefrom.

With the present processan excess of water is to be avoided and accordingly it does not depend so much on obtaining an exact percentage of caustic soda in the cellulose but on the percentage of soda lye relatively'to the pe'rcentageof active water, 1. e. there must be no excess of water either chemically or mechanically bound by the The smallest excess of water in the reaction'heat necessarily produced by the treatment with carbon bisulphide, be decomposed or matured, which shall by all means be prevented according to my new process.

In preparing solutions for the manufacture of artificial silk this danger is of no importance, as the hydrated cellulose fibres will absorb the carbon bisulphide much more readily and the spinningmaterial produced has to subsequently mature for several days.

Experience has shown that an excess of liquid not bound by the cellulose will naturally appear as soon as the cellulose contains, relatively toits weight more. than a 200% aqueous solution of soda. At 200% and less the xanthogenate consists of a crumbling mass, in which a gelatinization of the fibre has not yet occurred, so that the above described disadvantages as regards the solution and the spinning cannot appear.

lmiereas in the manufactureof artificial silk the alkali cellulose has to be subjectedto storage for several days at temperatures from 20-30" cent., in order that at the further proceedin of the process the typical high gloss of t e spun yarn is obtained, the alkali cellulose shall, according to the present new process, even during the brief period between the dipping and the treatment with carbon bisulphide, not be subjected to temperatures higher than 20, as at higher temperatures a deeper reaching change of the cellulose molecules will immediately occur, which will affect the condition of the viscose solution and the quality of the yarns spun therefrom unfavorably as regards the present rocess. I

lVhen the stated weight of the lye in the alkali cellulose and the temperatures are ob served to which the same is exposed until it is treated with carbon bisulphide, the spun material will possess the original properties of the cellulose to an almost full extent. It will combine a mild woollike gloss with a tensile strength which is 50% higher than that of the highly glossy artificial silk and the considerably increased strength in a wet condition is particularly remarkable. This strength is with the new product about 50% of its dry strength compared to only 30% with artificial silk. The wet strength is, thus, more than 100% greater than with artificial silk.-

In spinning thevabove described new cellulose solutions, it has been found that these solutions are not always obtained of the same quality and that'the yarn spun therefrom will, under circumstances be of a lesser strength. Careful investigations have shown that in such cases the cellulose employed possessed an increased oxidizing capacity, or that the soda lye was of an -unsuitable quality, containing, namely, some noxious substances, such as common salt to a high percentage.

Instead of the intended, reduced hydration of the cellulose, an oxidation of the cellulose will occur under action of the air, and this oxidation will result in a more or less weakened yarn. It is therefore necessary to obviate this danger of an oxidation.

An effective means forthis has been found in a comparatively small quantity of reduc ing substances which will not disturb the equilibrium of the solutions. Such substances are, for example, the various kinds of sugar which will burn in sodalye under absorption of oxygen tocarbonic acid. The oxidation threatening the cellulose will, when such means are employed, afiect only the readily decomposing sugar, whilst the carbonic acid produced will serve as a further. protection for the cellulose against oxidizing influences.

These reducing substances may be employed in the dipping bath used for producing the alkali cellulose; when, however, these baths are repeatedly used, such. reducing substances will form in them by themof the finished yarn, an average of about 5% sugar will sufiice, calculated I to the weight of the dry cellulose. The suitable quantity is determined according to thecondition of the cellulose and of the soda lye.

According to the present process, therefore, reducing agents, the action of which has been accurately recognized and gauged, are employed with a novel viscose solution producing a novel result, consisting "in an oxidation of the cellulose being avoided and a maximum strength of the yarn produced being secured.

E wdmple.

100 ko. dry cellulose are hydrated in the aforesaid manner and then treated with carbon bisulphide. The xanthogenate thus obtained is then dissolved in an aqueous o lution of caustic soda to which about 5 ko.

sugar have beenv added. The non-matured mass is thereupon spun in baths prepared from mineral acids. I

I claim:-

1. The process of producing I wool-like threads from cellulose materials which comprises treating cellulose with a solution of caustic alkali suficient to produce incomplete hydration without an excess of water, at a temperature not over 20 (3., transforming the cellulose into xanthogenate by carbon bi-sulphide, dissolving the xanthogenate in an aqueous solution of caustic alkali of 3% to 5% and spinning the solution in a mineral acid bath. 7

.2. The process of producing wool-like threads from cellulose materials which com-' is prises dipping 100 parts of a cellulose containing material. into a caustic lye of about 18% strength, at a temperature of about 18 C. allowing said cellulose containing material to remain in said lye about three hours, removing said lye from said cellulose containing material until it contains about 2 parts of lye to one part o flcellulose; then treating with 35% carbon disulphide, dissolving in about 1200 parts of an aqueous 2o solution of caustic lye at a temperature less than 15 'C. and spinning in a dilute mineral acid bath.

' 3. The process of producing wool-like threads from cellulose materials which com prises dipping 100 parts of cellulose into a soda lye of about,18% strength at a temperature 0 f about 18 C. allowing said cellulose to remain in said lye about three hours, removing said lye from said cellulose until it 80 contains about 2 parts of lye to one part .,of cellulose; then treating wlth carbon disulphide, dissolving in about 1200 parts of soda lye at a temperature less than 15 C.

- and spinning in a 12% to 15% sulphuric 35 acid bath.

4:; The. process of producing wool-like threads from cellulose materials which com prises dipping 100 partsof cellulose into a soda lye of about 18% strength at a temper- 4o ature of about 18 'C. allowing said cellulose naaaeae to remain in said lye about three hours, removing said lye from said cellulose until it contains about two parts of lye to one part of cellulose; then treating with 35% carbon disulphide, dissolving in about 1200 parts of 4% soda 1 e containing a carbohydrate other than cellu ose and spinning in a 12% to 15% sulphuric acd bath.

5. The process of producing wool-like threads from cellulose materials which comprises dipping 100 parts of cellulose into a soda lye of about 18% strength at a temperature of about 18 0. allowing said cellulose to remain in said lye about three hours, removing said lye from said cellulose until it contains about two parts of lye to one part of cellulose; thentreating with 35% carbon disulphide, dissolving in about 1200 parts of 4% soda lye containing about 5 parts sugar and spinning in a 12% to 15% sulphuric acid bath.

(LA soft wool-like cellulose thread obtained by treating cellulose with an 18% soda lye at a temperature of about 18 C. removing said lye therefrom until there is contained therein about two parts lye to one part cellulose; then treating the 35% carbon disulphide, dissolving in 4% soda lye con taining 5 parts sugar, at a temperature less. than 15 and finally spinning at a 12% to 15% sulphuric acid bath, said fibres being free from a silky lustre and having a tense strength greater than that of an artificial silk thread of the same size and material.

lntestimony whereof l have afixed my 75 signature in resence of two witnesses.

j Pl lUlL HERMANN EMINCK. Witnesses:

KARL Harem Pam, Knuec, JOHANNA Mencannrnm lPoLUs'rmoK.