US1074092A - Articles composed of cellulose esters. - Google Patents

Description

UNITED STATES P tZFENT OFFICE.

HARRY S. MORK, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO CHEMICAL PRODUCTS COMP ANY, 0F BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

ARTICLES COMPOSED OF GELLULOSE ESTERS.

No Drawing. Original application filed February 10, 1910, Serial No. 543,098.

filed May 19, 1910.

To all whom it may concern:

Be it known that I, HARRY S. Monk, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented an Improvement in Articles Composed of Cellulose Esters, of which the following is a specification.

In Letters Patent No. 1,061,771, dated May 13, 1913, a process of treating cellulose esters, such as cellulose acetate, is em bodied, consisting essentially in producing a lower cellulose ester of a fatty acid by removing from a higher ester a portion of the combined acid.

In carrying out the process therein set forth the higher ester of the fatty acid is treated with a saponifying agent until a portion of the combined acid is removed.

This invention relates to sheets, or films, filaments and the like, composed in part of the lower esters of the fatty acids, as the lower acetates, which also involves the exercise of the invention set forth in my aforesaid patent of which this application is a division, yet comprehends new and useful features.

This invention comprises sheets or films and filaments and the like, made of triacetate of cellulose, such as may be prepared according to my Patent #85 1374, and such portion thereof as is desired changed by the removal of a part of the combined acid, as hereinafter set forth. Such a sheet or film, filament and the like, is adapted for many uses where the qualities of the triacetate are desirable in some part of the sheet or film, filament and the like, and the qualities of a lower acetate are desirable in other portions thereof. For instance the back of a photographic film base may be composed of the triacetate and the surface composed of a lower acetate; or a pattern on the surface of the base may be composed of a lower acetate; or threads may have an interior of the triacetate and an exterior of a lower acetate; or a part of a film may be changed to the lower acetate from front to back, leaving the remainder unchanged. In short many combinations of this nature may be produced readily involving my invention.

In the process of my application aforesaid partial saponification or removal of a Specification of Letters Patent.

Patented Sept. 23, 1913.

Divided and this application Serial No. 562,318.

part of the combined acid of the ester is effected in a number of different ways and by the application of usual or suitable saponifying agents, such as sodium or potassium hydroxid, hydrochloric or sulfuric acid, or by some reagents not ordinarily used for the purpose, such as sodium carbonate and ammonia. For example, if cellulose triacetate prepared according to my Patent #854,374, be allowed to stand in aqueous ammonia of specific gravity 0.9 for fifteen or sixteen hours, at a temperature of say 15 to 20 (3., saponification will gradually take place, although conversion toward the di-acetate and the monoacetate will not take place in definite stages. These results may likewise be reached by using a stronger solution for a shorter time or the saponification may be carried further if desired by stronger chemicals, greater heat, or longer time or both.

In the present invention the sheets or films, filaments and the like, are treated superficially whereby a portion only of the sheet or film, filament and the like, is changed. Superficial saponification is read ily effected by subjecting the portion it is desired to change. from the triacetate to a strong hot caustic soda solution or other active saponifying agent for a very short time, as for instance, a 10% sodium hydroxid solution for one or two minutes at 60 or 70 C. The saponification will proceed further the longer the reaction is permitted to continue. Or a thin layer of a viscous menstruum, like a starch or gelatin solution containing the active saponifying reagent, may be applied to the surface of the film.

In case it is desired to effect saponification locally in spots or configurations on the surface, the thick solution can be printed upon the film in any desired pattern. For many purposes it is not harmful if the reaction continues-so long that the film is superficially saponified until the acid groups have been completely removed.

One example where the exercise of my invention is useful is in the treatment of cellulose acetate films for photographic purposes. I have discovered that when such films are partially or superficially saponified they are, by reason of this modification, put

in condition so that the gelatin emulsion or substratum will more readily adhere to them, owing to the increased water absorptive capacity of that portion which has been partially or completely saponified, and the properties of the film may be varied greatly according to the extent of the saponification. Another application is in the case of artificial silk. The number of dyes that can be dyed directly from aqueous solutions on artificial silk made from cellulose triacetate is very limited. When the artificial silk has been subjected to the action of a saponifying agent, in accordance with this invention, I find that. by reason of this treatment the number of dyes available for dyeing the material is very materially increased. Another advantage of the exercise of my invention is the fact that even if the original cellulose triacetate is very flexible and strong, the

flexibility and strength are noticeably increased by subjecting the triacetate to partial saponification. Furthermore, a sheet or film or a filament superficially saponified by my process is quite distinct from any sheet or film or filament which could be ,made by attempting to combinetwo sheets, one made of the triacetate and one of the tion of the combined acid.

2. As a new article of manufacture, a sheet,,film or filament composed of an 'in-. separable combination of cellulose of pro.- gresslvely varying degrees of acetylation-including the triacetate and a lower acetate prepared by removing superficially or 10-' cally from the triacetate a portion of the combined acid.

3. As a new' article of manfufacture, a sheet, film or filament of cellulose'triacetate having its surface saponified to produce "an article of. progressively varying degrees of acetyla-tion.

4:. Asa new article of manufacture, a film, filament, sheet or structure composed of cellulose of progressively varying def grees of acetylation and which 1s physically homogeneous but chemically heterogeneous in its relations to water, dyes and solvents.

5. As a new article of manufacture, a

sheet, film or filament composed of cellulose acetate, superficially saponified.

6. As a new article of manufacture, a

sheet, film or filament composed mainly of an acetate ofcellulose higher than the diacetate and having a surface composed of an v acetate of cellulose lower than the triacetate.

7 As a new article of manufacture, a base for a photographic film composed of a cellulose ester, superficially saponified.---

8. As a new article of manufacture,- a-base for a photographic film composed of a-cellulose ester, the surface of which is composed of a lower ester than the remainder.

9. As a new article of manufacture, a base for a photogra hic film composed of a cellulose ester, a portion of the surface of which is composed of a lower ester than the remainder.

.10. As a new article of manufacture, a base fora photographic film composed of triacetate of cellulose with a surface composed of a lower acetate of cellulose.

IL-As a new article of manufacture, a

photographicfilm-base having a surface of an acetate of cellulose lower-'than-the-triacetate and a base of a-liigher degreeof acetylatio'n than the surface.

base for a photographic'film cc i tin f a support comfposed of=triacetate of cellulose and: a sur 13. As a new photographic film-base comp f e of the triacetate of cellulose: superficially saponified;

In testimony whereof I have-signed my two subscribing-witnesses. Y

Witnesses: B. J. Norms,

Y H. B. 1'D'Av1s.-

ace composed of a lower acefate of cellulose inseparably combined with 'thesupport.

- 12. As a new 'article of manufacture, a

article of -ma-nufacture', a

name to this specification in the presence of