US2021887A - Cellulose mixed ester composition - Google Patents

Description

Patented Nov. 26, 1935 v I t v UNITED STATES PATENT c rr -ice CELLULOSE MIXED ESTER COMPOSITION Hans T. Clarke, New'York, and Carl J. Malm,

Rochester, N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of a New York No Drawing. Application April 9, 1931,

' Serial No. 528,966

a 10 Claims.- (01.106-40) Thisinvention relates to compositions of mat- Pending applications 6 and 7, ter in which mixed organic acid esters of cellulose filed March 28, 1927, now U. Patents 1,300,360 are homogeneously mixed with an aryl phosphate and 1,8 p ively- W y O the such as triphenyl phosphate, with or without mixed organic acid esters ,known, have been other useful addition agents, so that the resultd o pr duce valuable materials when coming product will have properties such as will billed With a y p p a od Of make the composition highly advantageous'for king ixed Organic d esters-are m n usein the plastic and analogous arts such, for and are shown for example in j Ol pinstance, as the manufacture of wrapping sheets, plications and patents and in the U. S. patents to photographic film, artificial silk, varnishes or .Clarke' and Malm, No.f, 8; 8, 0 8 lacquers, molded products and the like. 1,735,159, U. S. Patent No. 1,65'l'.991' to Berthon One object of this invention is to produce a, and British Patent No. 219,926 to Societe de composition of matter which may be made into Stearinerie et Savonhe'rie... v permanently transparent, strong and flexible However, prior to 0111 discovery. it s not sheets or films of desired thinness which are subognized that these mixed esters of cellulose could stantially waterproof, are unaffected by ordinary e as i i d or a these esters e more photographic fluids and possess the desired propcompatible with the aryl phosphates than celluies of a support for sensitive photographic lose acetate. We have found that the aryl phoscoatings. phates, when added to mixed organic'acid esters Another object of our invention is to produce of cellulose, do plasticize these esters and produce a composition which is capable of easy and. conmaterials therefrom of highly desirable characvenient manipulation in the plastic and analoteristics such as flexibility, stability, non-ingousarts, such-as in the manufacture of thin flammability, smoothness, transparency, etc.

sheets suitable for wrapping articles of com- The addition of aryl phosphates to cellulose ace- 25 merce, films, artificial silk filaments, -varni shes, tate is well known, but cellulose acetate offers the lacquers and the like; and to produce a compos'idisadvantage in this connection of permitting tion which will not injure or be injured by, the only a limited amount oftriphenyl phosphate, substances or surfaces with which it is associated for instance, to be incorporated therewith. This during manufacture, storage for use. Other and disadvantage obviously limits the number of com-- 30 further objects will hereinafter become apparent binations, for instance, of triphenyl phosphate to those skilled in the art to which this invention and cellulose acetate which are possible, and conpertainssequently, the properties of cellulose acetate can We have found that when the mixed organic only be improved to a certain extent. We have acid esters are colloidized or physically combined found the triaryl' phosphates to be compatible with a triaryl phosphate, the value of the resultwith the mixed organic esters of cellulose in a far 35 ing product is considerably enhanced for the greater range of proportions than they are with various purposes mentioned above, as disclosed incellulose acetate. We have prepared composiour co-pending U. S. application Serial No. tions containing as much triphenyl phosphate as 179,177 filed Mar. 28, 1927, now U. S.- Patent No. the amount of cellulose ester present and they 1,880,808, of which this application is a continuwere found to be homogeneously combined. We 40 ation-in-part. The instant application is also in have yet to'find a combination of these ingredipart a continuation of our copending application ents which will not form a homogeneous com- Serial No. 520,151, filed March 4, 1931 (later position. Whereas cellulose acetate is tolerant of abandoned) disclosing mixed organic acid esters only about 30% of its weight of triphenyl phosof cellulose plasticized with a plasticizer such as phate and about 20% of tricresyl p p the triphenyl phosphate and containing claims mixed esters as exemplified by cellulose acetatethereto. In addition to plasticizing the mixed propionate are tolerant of an unlimited amount esters of cellulose, the triaryl phosphates also of triphenyl phosphate and of or even more have been found to materially reduce the inflamof tricresyl phosphate. Thus, the de e of 50 mability of the mixed esters so that any danger tening of thecellulose mixed organic acid ester 5 from rapid burning in, for instance, its use as film desired may be readily obtained. Other triaryl befiomes eliminated phosphates than those mentioned, such as mono- Anv of the mixed organic acid esters of cellucresy diph nyl p ph t 'trinaphthyl p oslose may be employed in' our composition of phate, etc., also come within the scope of our matter, especially-those contemplated in our coinvention. 55

, acetate-stearate-palmitate, cellulose propionatestearate, cellulose butyrate-stearate, cellulose acetate-crotonate, cellulose acetate-oleate, cellulose acetate -laurate, cellulose acetate-laurate-myristate. t

From the above list, it may be noted that the mixed fatty acid esters of cellulose are particularly suited to our composition of matter. The term fatty acid as used herein is understood to include both the saturated and unsaturated series or, as they are commonly known, the acetic and the oleic acid series of acids. 7

In order that those skilled in this art may better understand our invention, by way of illustration the following is an example of a composition of matter which is quite suitable for the manufacture of photographic film or other sheets: about 100 parts of a cellulose acetate-propionate containing from 20% propionyl radical is dissolved with stirring at atmospheric temperature in about 400 parts of acetone. To this solution is then added 30 parts (or any amount desired for,that matter) of triphenyl phosphate. The amount of plasticizer which one may use depends on the particular condition desired in the final product. For example, if one desires a softer, more pliable and flexible product than that obtained by employing 30 parts of triphenyl phosphate, a greater amount of plasticizer-may be used. There need be no fear of incompatibility of, the two ingredients when a larger amount of plasticizer is incorporated into a mixed organic acid ester of cellulose to form the product of our invention.

- The following illustration discloses the com- .poundingof a product which may be employed for the manufacture of a thin'sheeting, for example, for wrapping purposes; 100 parts of a cellulose acetate-stearate having an acetyl content of about 40% is dissolved in about 500 parts of ethylene chloride. 10-20 parts of tricresyl phosphate may then be'added to this solution although, as stated above, the degree of flexibility desired will determine the amount of plasticizer which should be incorporated.

In substantially the sameman'ner as triphenyl phosphate ,is employed, we may also compound tricresyl phosphate with the mixed organic esters of cellulose except that not much more than 50 parts of tricresyl phosphate should be added to- .oils may be added to our composition while it-is still in solution. v

A composition of matter, such as above described, may be deposited upon any suitable film forming surface to form a film or sheet, asis well known to those skilled in the art. A film so produced has permanent brilliancy, transparency and low inflammability, burning even less readily than ordinary newspaper. Such film is tough and flexible as shown by the fact that it will withstand many folds upon a modified Schop- 5 per fold-tester (commonly used for such purposes) without breaking and that even after being subjected for a number of weeks to air maintained at 65 C., the film still maintains fiexibility, demonstrating that the film will withstand 10 ordinary'usage satisfactorily for years.

Other solvents such as ethylene chloride, ethyl acetate, chloroform-alcohol, etc., which are compatible with the particular mixed ester and plasticizer used, may be employed instead of acetone if desired. Also, instead of forming a composition of a single mixed ester and a single aryl phosphate, compositions may be produced in which mixtures of mixed esters and/or mixtures of various aryi phosphates may be employed. As stated before, simple esters may be incorporated in our composition together with mixed esters. In some cases the mixture of a simple and mixed ester results in a greater flexibility and resistance to moisture than is exhibited by either by itself. 5-

The preparation of compositions of matter, or articles therefrom, by dissolving the cellulose mixed organic acid esters or the cellulose higher esters in ethylene chloride is not our joint invention but is the sole invention of Carl J. Malm, one of the applicants herein, as set forth in his application Serial No. 551,545, filed July 17, 1931.

In addition to its utility in the production of films and sheets, our composition of matter may alsobe employed with advantage in other branches of the plastic art. For example, our new composition of matter may be employed in the manufacture of artificial silk by the dry spinning method. It may be desired to employ a composition of different viscosity or evaporation characteristics, but this is a mere matter of changing the solvent proportion or adding evaporation retardants, such as higher alcohols or other higher or intermediate boiling constituents as has been well known in the art for more than a decade.

Our new composition of matter may be substituted to advantage for other cellulose derivative materials, in a number of the known lacquer formulas where they are compatible. Other uses within. the scope of our invention will also suggest themselves to those skilled in the art such as the production of molded articles by heating under formed into a film or sheet, comprising a mixed 0 organic acid ester of cellulose and an amount of a triaryl phosphate sufiicient to increase the flexibility of said fllm or sheet substantially beyond the inherent flexibility of an unplasticized film or sheet of the mixed organic acid ester of cellulose, without substantially impairing its transparency.

2. A composition of matter adapted to be formed into a film or sheet, comprising a mixed organic acid ester of cellulose and an amount of a triaryl phosphate, selected from the group consisting of triphenyl and tricresyl phosphates, suflloient to increase the flexibility of said film or sheet substantially beyond the inherent flexibility of an unplasticized film or sheet of the mixed and cellulose acetate-butyrate, and an amount of triphenyl phosphate sufllcient to increase the flexibility of said film or sheet substantially beyond the inherent flexibility of an unplasticized; film or sheet of the mixed organic acid ester of cellulose, without substantially impairing its transparency.

4. A composition oi matter adapted to be formed into a fllm or sheet, comprising a mixed organic acid ester of cellulose, selected from the group consisting of cellulose acetate propionate and cellulose acetate-butyrate, and an amount of tricresyl phosphate sufllcient to increase the flexibility of said film or sheet substantially beyond the inherent flexibility of an unplasticized fllm or sheet of the mixed organic'acid ester of cellulose, without substantially impairing its transparency. v

. 5. A composition of matter comprising a mixed organic acid ester of cellulose and ill-100% oi triaryl phosphate.

-6. A composition of matter adapted to be formed into a fllm or sheet, comprising a fully esterifled mixed organic acid ester of cellulose and an amount of a triaryl phosphate suillclent to increase the flexibility of said fllm or sheet substan tially beyond the inherent flexibility 01' an'unplasticized fllm orsheet oithe mixed organic acid ester of cellulose, without substantially impairing its transparency. q

o. 'I. A transparent, flexible sheet comprising a mixed organic acid ester. 01 cellulose and an amount of a triaryl phosphate .suilicient to ins crease the flexibility of said sheet substantially 4 beyond the inherent flexibility of an unplasticised sheet the mixed organic acid ester of cellulose,

- without substantially impairing its transparency.

-8. A transparent, flexible sheet comprising cellulose-acetate-propionate and an amount 0! a "triaryl phosphate sufllcient to increase the flexibility of said sheet substantially beyond the inherent flexibility of an unplasticized sheet of cellulose acetate-propionate, without substantially impairing its transparency.

8. A transparent, flexible sheet comprising a iully esterifled mixed organic acid ester of cellulose and an amount of a triaryl phosphate suflicient to increase the flexibility oi said sheet substantlally beyond the inherent flexibility of an unplastlcized sheet oi the mixed organic acid ester of cellulose. without substantially impairing its transparency.

10. A transparent. flexible sheet comprising fully esterifled cellulose-acetate-propicnate"and an amount oi a triaryl' phosphate sufllcient to increase the flexibility of said sheet substantially beyond the inherent flexibility of an unplasticiaed sheet of cellulose .acetate-propionate, without substantially impairing its transparency.

HANS 'r. cmaxn.

cam. J. muss.