US2059934A - Process of treating organic esters of cellulose - Google Patents

Description

Patented Nov. 3, 1936 UNITED STATES PATENT OFFICE PROCESS OF TREATING ORGANIC 'ESTERS OF CELLULOSE Alma Dobry, Paris, France, assignor to Compagnie de Produits Ghimiques et Electrometallurgiques, Alais, Frogcs et Camargue, Paris, France, a corporation of France No Drawing. Application January 24, 1935, Serial No. 3,364. In France February 21, 1933 6 Claims. (Cl. 1854) The present invention relates to a method of form of an even sheet on a solid surface, either treating organic esters of cellulose, which is movable or not, and will furnish, after coagubased on a property of said bodies that was not lation in a bath of water, a film which can be known up to the present time and therefore was used as a support for photographic gelatine. Or

never used for practical purposes. This propagain a vegetalor metallic fabric canbe impreg- 5 erty is the solubility of these bodies in the aquenated with the solution of cellulose acetate and ous solutions of a great number of metallic salts subjected to the action of water, which will proof perchloric acid. duce ultra-filter membranes. Ordinary paper Cellulose acetate, of the composition generor filter paper can also be treated in the same 10 ally employed in the art (soluble in acetone), is manner. They will thus be strengthened and e soluble in the cold state in concentrated and made watertight, which will make it possible to neutral aqueous solutions of the perchlorates of obtain either reinforced filter paper or parchberyllium and of aluminium, and in those of ment paper resisting the action of water. The magnesium, calcium, lead (neutral or basic applications of the process according to the presl5 salt), copper, zinc, strontium, barium, lithium. ent invention are not limited to the examp The solutions remain sufficiently fluid in the cold above stated.

state up to a concentration of cellulose acetate Such perch o a Solutions y be ed W of about 15%. At a higher temperature, the one another before coagulation. For instance, concentration can be further increased. I may miX perehlorevted Solutions of diaeetyl- Primary cellulose acetate, or triacetate, is not Cellulose, of triecetyleellulose and of cellulose, 2 directly soluble in solutions of metallic perchloin such manner as to obtain a mixed pro rates. But if it is previously dissolved in a solthe cost of which is lower than that of p vent, such as methyl formiate, and if the oluacetylcelluloses. (The perchlorated solutions of tion thus obtained is mixed with an aqueous so cellulose have been described in my U. S. patent lution of beryllium or aluminium perchlorate, application 712,059 filed February 25 the acetate remains in the dissolved state and 1934, now Patent 2,022,539 of Which the present the mixture can be freed from methyl formiate, application is a Continuation in p I y without precipitating. It is thus possible, through also incorporate with the perchlorated solutions an indirect method, to dissolve triacetate in vari us nit n u p du t su s gelatine,

perchlorates. fibroin, natural silk. These mixed solutions, 30

The perchlorated solutions thus obtained, wh n ooaeulated. y means f w r, r in either of cellulose diacetate (acetate soluble in to the examples ab Stated. yield new P acetone), or of triacetate, coagulate instantan ts i W h the presence of the it nous neously by contact with water and the organic matter ensures the p p of being e ea y ester of cellulose is regenerated, without any dyed than purely oellulosio products a nearly 35 alteration. Furthermore, the coagulation baths as easily dy as W001 Silk, though h ess containing perchlorate regenerate, by mere expensiveevaporation, Without any loss, the solvent ready Of c for e particular pl it is to dissolve again a new amount of cellulosic advisable to determine the nature of the p product, and so on. chlorate that gives the best results, and also the 40 The properties that have just been described b st condit ons of Wor ing. The following specan be applied in many ways to industrial cific process s will now be given y Way of manufactures or operations. For instance, the examp solution of cellulose acetate can be forced Erwmple 'mmes of commercial through pieces provided with fine holes and imcellulose acetate soluble in acetone are dissolved 45 mersed in a bath of water; the cellulose acetate in 100 kilogrammes of a saturated solution of then coagulates in the form of a thread which, magnesium perchlorate as pure as possible. after washing and drying, will furnish artificial After homoge a solution is obtained which silk or artificial horse-hair. precipitates immediately, under the action of The solution of cellulose acetate can also be water, regenerating the acetate, and which can be 50 forced through a narrow slot immersed in water utilized for the obtainment of transp fi s and will thus furnish, after washing and dryor artificial silks. ing, a strong thin sheet, adapted to be used, for Example II.2 kilogrammes of gelatine are instance, for fine wrappings. Or again the somixed with 500 litres of a saturated solution of lution of cellulose acetate will be poured in the magnesium perchlorate. After dissolution of the 55 gelatine, kilogrammes of cellulose diacetate are added thereto. The solution thus obtained can be used for manufacturing artificial textiles having dyeing properties more advantageous than those of cellulose acetate alone.

Cellulose formiates and acetoformiates are also very easily dissolved in saturated aqueous solutions of metallic perchlorates and more especially in solutions of magnesium perchlorate. These solutions precipitate very easily under the action of water, giving threads or films which possess interesting mechanical properties. The solutions of cellulose formiate thus obtained can be employed, either alone or mixed with solutions in perchlorate of cellulose acetate or of cellulose, in all the known fabrications that make use of cellulosic solutions, such as the preparations of artificial textiles, of thin films for wrapping or photography, of tulles, artificial leathers and so on.

Example HI.-5 kilogrammes of cellulose formiate are mixed with 50 litres of a saturated solution of magnesium perchlorate. After homogenizing and filtering, the solution that is obtained can be employed for the manufacture of artificial silk by means of known apparatus, use being made, as coagulation bath, of water or saline solutions.

The diluted solutions of metallic perchlorates that remain after precipitation of the organic esters of cellulose can be easily concentrated again by evaporation, with extremely low losses, so that they can be reutilized for subsequent operations. Precipitation can also be obtained by utilizing, instead of water, other coagulation baths such as saline or acid solutions which modify the characteristics of the products obtained.

What I claim is:

1. A process of treating an organic ester of cellulose, which comprises forming a solution of said ester in a concentrated aqueous solution of a metallic perchlorate, and treating with a liquid adapted to cause the separation of the perchlorate from the organic ester of cellulose.

2. A process of treating an organic ester of cellulose of the type soluble in metallic perchlorate, which comprises substantially dissolving the same directly in a concentrated aqueous solution of a metallic perchlorate, and precipitating the organic ester of cellulose by means of a liquid from the solution thus obtained.

3. A process of treating an organic ester of cellulose, which comprises substantially dissolving the same in a concentrated aqueous solution of beryllium perchlorate, and precipitating the organic ester of cellulose by means of a liquid from the solution thus obtained.

4. A process of treating an organic ester of cellulose, which comprises substantially dissolving the same in a concentrated aqueous solution of aluminium perchlorate, and precipitating the organic ester of cellulose by means of a liquid from the solution thus obtained.

5. A process of treating an organic ester of cellulose, which comprises substantially dissolving the same in a concentrated aqueous solution of magnesium perchlorate, and precipitating the organic ester of cellulose by means of a liquid from the solution thus obtained.

6. A process of treating an organic ester of cellulose, which comprises substantially dissolving the same in a concentrated aqueous solution of a metallic perchlorate, and precipitating the organic ester of cellulose by means of water from the solution thus obtained.

ALMA DOBRY.