US767943A - Process of dissolving nitrated cellulose. - Google Patents

Description

v and are therefore unsuited'for the purpose for which the nitration is carried on.

, formed which are to a slight degree soluble in the same solutions as the tetrates are soluble. This waste cannot be used for the purpose of To all whom it may concern.-

No. 7c7,943.

UNITED STATES Patented August "16, .1904.

PATENT OFFICE PROCESS OF DISSOLVING NITBATED cELLuLosE,

SPECIFICATION forming part, of Letters Patent No. 767,943, dated August16, 1904.

Original application filed September 9, 1899, Serial Ne. "729,937.?

- Aprillfi, 1904. serial No.

Be it known that I, ISIDOR Krrsnn, of the city and county of Philadelphia, State of Pennsylvania, have invented certain new and use 1 ful Improvements in the Process'of D'issolving N itrated Cellulose, of which the following is a specification.

, My invention relates to improvements in the process of dissolving nitrated cellulose.

On September 9, 1899, I filed an application for the same subject-matter, which application bears Serial No. 729,937, and this present application is a division of the former appli cation, which division was calledfor in ofiicial letter dated October 9, 1899, and this my invention has more special reference to the process of dissolving nitrated cellulose with the aid of the fumes of a suitable solvent.

It is well. known to the persons employed in the manufacture of nitrated cellulose for explosive purposes, as wellas for commercial purposes in general, that a great percentage of the cellulose is a waste product, for the reason that it is hardly possible to bring the whole mass to be nitrated to one and the same condition.

In the production of gun-cotton the nitration has to be so far advanced that a hexanitrate is produced. All particles not nitrated so highly are only detrimental to the product and are waste. Again, in the manufacture of celluloid and like compounds the nitration is only carried out to the point known in the art as triple or quadruple. In all these processes certain groups of nitrates are formed which have different composition More especially is this the case in the production of explosive nitrates. Compounds are.

making of same products known in commerce as celluloid, Xyonite, pyralin, &c. They are wastes that have to be worked over and the composition of which is oftensuch as not to compensate for the reworking. These wastes cannot be dissolved with the aid of Divided and'this application filed February 9. 1900. Renewed 203,376. (No specimens.)

heat or pressure in their dry state, for the reason that they are of too explosive a nature.

,Most of these wastes are soluble in concentrated acetic acid, and more so with the addition of a high temperature; but they are not soluble in acetic acid below eighty per cent.

- The difliculties of working with a strongly- ,concentrate'd acetic acid are twofold: first, the detrimental effect on the health of the persons working with such solution, which prevents entirely-the open working with such acid; second, the price 'of the concentrated article, which for all practical purposes is-prohibitive. At the same time when a thirtyper-cent. solution is'quoted in the market at about one dollar and fifty cents a ninety-percent. is quoted from eighteen to twenty-live dollars, according to the degree of purity.

The objects of my invention are to obviate these difliculties, to enable persons to use waste products of nitration, to dissolve these waste products with'the aid of acetic acid, and to use the cheap and not concentrated solution for this purpose.

As said above, the explosive nature of the waste product prohibits the working of same in a drystate under pressure or with the aid of heat. It is, therefore, for the sake of security necessary to dissolve this productin its moist'state and not to let it dry before it is dissolved; but the presence of water in the cellulose is detrimental to the process of dissolving it with most of the known solvents.

In the practice of my invention the presence of the moisture in the cellulose is not only not detrimental, but it is a necessity where solvents such as acetic acid and similarones are used. Through it I am enabled, as will be hereinafter more fully set forth, to make use of the cheapest grade of solvent.

Themodus opcrcmdc' of practicing my invention is as follows: The waste product, no

matter if one or more groups of different nitrations are present or if all or part only is soluble, is placed into the receiver of a distilling apparatus in a manner so that fumes passing through said receiver will have to penetrate every particle of the material. This receiver is connected with a-retort filled with acid fumes alone would not be capable of acting as solvent, and the presence of the moisture in the cellulose is therefore a necessity. After the dissolving process has been carried on to a point necessary for the intermixing of the dissolved product with an unnitrated cel lulose the contents of the receiverare dumped into what is technically called the mixture. In this mixture is also placed the necessary amount of unnitrated cellulose, which preferably consists of paper-pulp, raw cotton, hemp,

or flax, in the proportion of about fifty per cent. of paper-pulp or thirty per cent. of cottonor flax. After the nitrated and unnitrated material has been thoroughly intermixed the compound may be placed in molds and formed into any desired useful articles.

I am well aware that nitrated and unnitrated cellulosehas been used in the art, and applications therefor were made by me at different dates; but the great advantage of this my new process consists in the following: first, the use of the waste product of nitration, no matter how many different compositions this waste product contains, which waste product was formerly without any exception either thrown aside or had to be reworked; second, in the working of this waste product in its wet state, which evades the danger that accompanies the handling of such waste product if in a dry state; third, the use of a comparatively weak acetic acid as a solvent; fourth, the combination which consists in the use of the moisture present in the cellulose before drying as a vehicle, and therefore coagent of the dissolving process.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The process of dissolving nitrated cellulose, the same consisting in subjecting nitrated cellulose in moist condition to the fumes of a suitable solvent.

2. The process of dissolving nitrated cellulose, the same consisting in subjecting nitratcd cellulose in moist condition to the fumes of acetic acid.

In testimony whereof I hereby sign my name, in the presence of two subscribing witnesses, this 2d day of February, 1900.

ISIDOR KITSEE.

Witnesses:

EDITH P. STILLEY, A. P. Rn'rnnarom).