US1709513A - Process of forming cellulose products - Google Patents

Description

Patented Apr. 16, l-929.

' UNITED STATES No Drawing.

This invention relates to processes of forming cellulose products, and more particularly to a process of forming finished products from acetyl nitro cellulose in which the acetyl nitro cellulose, while still in the acetylizing solution, is diluted to a desired consistency and then submitted to the usual spinning operation, or other finishing step to produce a desired product.

In the use of cellulose acetate or mixtures of cellulose acetate and nitro cellulose, it is customary to remove the material from the acetylizing solution, by precipitation, thus obtaining a solid substantially dry. material I which is then spun or otherwise treated to produce a finished product.

In a copending application Serial No. 638,391 filed May 11, 1923, we have disclosed andclaimed a cellulose material consisting of both nitro and acetyl groups in combination with the cellulose group, a product which is truly an acetyl nitro cellulose. We have found that this material ,may be spun ,or otherwise treated to produce a finished 2 product without first removing it from the acetylizing solution by first reducing the consistency of the solution containing the acetyl nitrocellulose to a workable consist-2 ency. The fact that this acetyl nitro cellulose may be treated to produce a finished product without first removing it from the acetylizing solution enables us to save considerable time and labor in the production of the finished product.

In the preferred practiceof the process, the solution obtained when the nitrocellulose is acetylized, consistingof acetyl nitro cellulose in a mixture of acetic acid and aceticanhydride, which is in the form of a 40 thick, viscous jelly obtained from the acetylizing reaction, as describedin our copending application, 'is treated with glacial acetic acid to reduce the consistency to a point where the material may be spun. In place of glacial acetic acid, a"weak"solution of acetic acid'may beemployed and a sufiicient amount of thisweak acetic acid is addedto the acetylizing solution, containing the. acetyl nitro cellulose to reduce the consistency Application filed May 11';

PATENT OFFICE. 4,-

nnnmr r.- :sAssmr, or CYNTHIANA, xnn'rucxy, AND rnonlms F. BANI'GAN, or PHILA- nnnrnm, PENNSYLVANIA, n ssrenons 'ro MEIGS, na'ssn'rcra SLAUGHTER, me, or PHILADELPHIA, PENNSYLVANIA, a CORPORATION or PENNSYLVANIA. H

rnocnss or FORMING CELLULOSE rnonucrs;

v192:2. Serial no. 638,39. v

to the point where the acetyl nitro cellulose is just about to be precipitated. This niaterlal-consistmgeither-of the acetylizingsolution containing acetyl nitro cellulose which has been treated with acetic acid, or

consisting of the acetylizing solution con-.

taining acetyl nitrocellulose which has been treated with a weak solution'of acetic acid, as above described, may then be spun to pro duce artificlal silk and other filament-s or may be treated in the usual-manner-to form photographic films or other finished products. I

In forming artificial 'silkfand other fila-- .ments, the material is spun'through a precipitating bath. Where the consistency. of the solut on has been reducedby the use of glacial aceticacid, this bath may consist of a mixture .of acetic acid and water, of about to ;per cent acetic acid. When weak acetic acid hasbeen used to reduce the solution to almostthe point-of precipitation of the acetyl nitro cellulose, a precipitating bath of very weak acetic acid may be used.

In either instance, the spinning mixture can be spun through a precipitating bath of acetic acid and an inert liquid, such as benzol. The benzol, or other inert liquid, is' employed to permit recovery of the acetic ztrnhydride contained in the spinning soluion. I

As stated, the fact that this material may be submitted to finishing steps to form finished products without removing it from the acetylizing solution is a material .advantage, in that it saves considerable time and labor in the elimination of the precipitating step.

While we have described in detail, the-preferred practice of our process, it is to be understood that the details of procedure may be widely varied without departing from the spirit of the invention or the scope of the subjoined claims.

We claim:

1. The process of forming cellulose products which comprises bringing an acetylizing solution containing acetyl nitro cellulose to a point just above the precipitating point of the acetyl nitro cellulose, and then subof the acetyl nitro cellulose; and then mitting it to a finishing step to produce a spinning the acetyl nitro cellulose Without desired product. removing it from the solution. 10

2. The process of forming cellulose prod- In testimony whereof, We afllx our signe- 5 ucts which comprises bringing an acetyliztures. I

ing solution containing acetyl nitro cellulose HARRY P. BASSETT. to a point just above the precipitating point THOMAS ll. BANIGAN.