US2430254A - Fibrous sheet material for producing dyes thereon by electrolytic oxidation - Google Patents

Description

Patented Nov. 4, 1947 FIBROUS SHEET MATERIAL FOR PRODUC- ING DYES THEREON BY ELECTROLYTIC OXIDATION Myer Solomon, deceased, late of Westmont, N. J.,

by Nellie W. Solomon, administratrix, Princeton, N. J., assignor to Radio Corporation of America, a corporation of Delaware No Drawing. Application December 23, 1942, Serial No. 469,959

5 Claims. I

This invention relates to the electrolytic formation of quinoneimine dyes, particularly in connection with facsimile recording.

Various different types of facsimile receivers are used at the present time, and these are referred to in the copending application Serial No. 178,743, filed December 8, 1937, now U. S. P. 2,306,471, granted December 29, 1942, of which the present application is a continuation-in-part. Attention is directed to the rsum of the prior art given in said patent over which the present application constitutes an improvement.

In the present invention, it is proposed to produce the picture or printed matter on the recording paper in the form of a quinoneimine dye, the amount of such dye deposited being a function of the amount of current caused to flow through the recording paper. When the image is so formed, the pressure of the printer bar is maintained constant and the amount of current which is passed through increments of the paper is varied in accordance with the light and dark portions present on the picture or printed matter being scanned at the facsimile transmitter. When dyes are so formed by electrolytic action, varying half tone shades may be produced by merely regulating the amount of the current which is caused to flow through the recording paper.

In the present invention, facsimile recording is accompanied by electrolytic oxidation or forming quinoneimine dyes by electrolytically oxidizing chemicals that react to produce such dyes when oxidized.

The principle of operation of the present invention resides broadly in the fact that certain compounds or solutions produce quinoneimine dyes when oxidized. When any neutral, mildly acid, or mildly alkaline electrolyte is subjected to an electric current, acidification and oxidation are brought about at the positive electrode while the electrolyte is alkalized and reduced atthe negative electrode. Such oxidation is attributable to the nascent oxygen available at the positive electrode while the electrolyzing current is flowing. When there is present in the electrolyte, under these circumstances, compounds capable of oxidizing and coupling, such as, an aromatic paradiamine and an aromatic compound having an unsubstituted ring position para to an amino or hydroxyl group, quinoneimine dyes are formed.

It is accordingly an object of the present invention to form quinoneimine dyes by electrolytic oxidation of certain compounds.

Another purpose of the present invention resides in the formation of quinoneimine dyes by passing an electric current through a solution whereby the solution may be oxidized at the positive electrode to produce such a dye.

A further object of the present invention is a fibrous sheet material carrying an electrolyte and components capable of forming quinoneimine dyes by electrolytic oxidation.

Other purposes and advantages of the present invention will become apparent to those skilled in the art from the following more specific description of the present invention.

The essential components of the composition applied to the carrier which is a fibrous sheet, film, foil or the like, are the electrolyte and the components which are oxidized to produce the desired dyestuff. As the electrolyte, sodium chloride is preferred. This compound is generally used in a quantity such that a liter of solution will contain sodium ions equal to .1 to 3 gram molecular weights. Preferably, however, the concentration of sodium ions is about 1 gram molecular weight per liter. In lieu of sodium chloride there may be used other neutral electrolytes such as sodium bromide, potassium bromide, potassium chloride, lithium chloride, barium chloride, calcium chloride, magnesium chloride, potassium sulfate, sodium sulfate, magnesium sulfate and the like.

It is obvious that various appropriate chemicals may be added to deepen the color or to improve the background permanency. The substitution of barium (and sometimes calcium) chloride for part or all of the sodium chloride makes the colors more blue in shade and faster to washing, but such substitution usually lowers the solubility of the dye chemicals and not infrequently causes the formation of sludges which are of course objectionable. of iron, chromium, or other metals sometimes improve the fastness of the dye to washing and deepen the shade, or even change the color, of the dye. The addition of tartrates, formates, sulphites, hydrosulphites, thiosulphites, and/or other reducing agents results in a retardation of the background darkening, and in an extension of the useful working life of the solution by preventing slow chemical changes during storage, but is sometimes objectionable inasmuch as such reducing agents tend to decrease the sharpness of the detail of the recordings, to weaken the color of the dyes formed, and to require more electric current to produce the color.

The following example illustrates the forma- Complex cyanides tion of quinoneimine dyes in electrolytic facsimile recording:

EXAMPLE Quznonimine dyes (union of two dye intermediates by oxidation) Ingredients Formula gggilt Grains (I) paramincdimethylanilinehydrochloride NH: N(CHa)2'HC1 3. 46

NHr-HCI (II) metaphenylenediaminedihydrochloride. 3. 62

NHs-HCI (III) common salt NaOl- 68. 47 (IV) Water to a total volume of one liter.

The ingredients are dissolved in water, giving a pale yellow solution. With a copper-containing positive electrode deep greenish-blue recordings on a white background are obtained, the color appearing on both sides of the sheet. With a steel positive electrode the color is weaker, and in a few minutes fades out to a still weaker shade. N o recordings have been obtained with platinum, platinum-iridium, or tungsten electrodes. On standing for several days, the copper-produced recorded areas darken to blue-black, and the background also darkens. This darkening is greatly reduced, but not eliminated, by washing the recordings with water within a few hours of their formation. The reaction is general in scope,

as ingredient (I) may be replaced by other paradiamines or by para-amino phenols, and ingredient (II) may be replaced by other aromatic compounds having an unsubstituted ring position para to an amino or hydroxy group. Among the chemicals that have given this type of facsimile recording are:

Ingredient I p-Aminodimethylaniline p-Arninodiethylaniline p-Phenylenediamine p-Aminodiphenylamine p-Aminodiphenylamine sulphonic acid p-Aminophenyl-p-tolylamino sulphonic acid Ingredient II m-Phenylenediamine Alpha naphthylamine Alpha naphthol Gamma acid Chicago acid S-hydroxyquinoline GENERAL DISCUSSION In any of the above mentioned examples it will be noticed that the electrodes per so do not play any part in the formation of the dye other than as a means for subjecting the solution to an electric current, or as in the case of some oxidation dyes, where they may act as catalysts. The metal or material of which the electrodes are made does not combine with the solutions or chemicals and does not enter into the composition of the electrolytically produced dyes. The electrodes may, in' some instances, prevent the formation of the dye as stated above and by selecting a metal which will prevent dye formation for one of the electrodes the dye may be permitted to form on one side of the paper and trodes frequently is of particular advantage where alternating current is applied to the electrodes, or where the unrecorded side of a facsimile recording is to be used for a subsequent recording.

By the use of any of the above mentioned solutions and compounds, it is possible to produce dyes and pigments by subjecting solutions or mixtures of'chemicals to an electric current. Such dyes or pigments may then be collected in a paste, powder or liquid form and subsequently used for coloring paints, inks, etc. or for dyeing various materials. Also, materials such as clothing, piece goods, yarn, etc., may be dyed by immersing such material in a container which has been filled with the solutions and subsequently subjecting the entire mixture to the flow of an electric current in order that the dyes may be fixed in the materials so immersed. This method produces a uniform coloring of the material, particularly when some agitation is present during the time that the electrical current is applied to the solution.

If it is desired that not all of the material be subjected to the electrical current in order that varying intensities of colors may be produced, or that designs or other patterns be printed on the material, it is obvious from the above that only portions'of the material, allof which has been treated with the proper chemicals, need be subjected to the electric current and such selectivity of activation may be accomplished by controlling the distribution of current to various portions of the material either by controlling the current per se or by applying a non-conducting material such as varnish, lacquer, parafiin, etc., to the material where it is desired that no current'shall pass and no color shall be present. Furthermore, the material may be passed between a pair of rollers which are to act aS electrodes of an electric circuit and wherein one or both of the rollers is recessed or engraved or otherwise altered in contour or provided with non-electrically conductive areas in order that only portions of the material passing between the rollers will be subjected to the passage of current.

It is to be understood that,'although the present invention is concerned primarily with the reproduction of printed matter, pictures, etc, by a facsimile system, the invention may well be applied to other fields, and in' combination with other methods of dye formation.

Furthermore, it is to be understood that the invention, when applied to a facsimile receiver, may be used in such a mannerasto produce a continuous process wherein the paper to be 5. printed is fed from a'roll and passed through the solution in order to .sensitize the same. The paper so sensitized may then be directly transferred or fed to the facsimile receiver at which point the electric current causes the solution contained in the paper. to be changed into dyes in accordance with the values of the electric current. If desired, after passsing through the facsimile receiver, the paper may or may not be automatically or otherwise exposed to light and/or directed to a fixing bath and subsequently washed in order to reduce the tendency for the background to discolor. After the paper has been washed it may then be passed automatically or otherwise to a dryer at which point the facsimile reproduction is completed and ready for perusal and storage.

It is also to be understood that sheets of paper or material may be impregnated with one or another of the various solutions and the paper permitted to be subsequently dried. When the paper is dry it is relatively non-conducting and is not in a proper condition to be operated upon by the passage of electric current, The paper may then be humidified or dampened by any appropriate means, such as by steam or water vapor, for instance, in order to increase the conductivity thereof and the paper may then be placed in the facsimile receiving machine for use. By so preparing separate sheets of paper or separate rolls of paper it is possible to use the sensitized paper by merely subjecting the same to a certain degree of moisture in order that the current may pass therethrough and accordingly cause a dye to appear on the paper.

It is also to be understood that paper, cloth, or other materials on which dyes are to be produced electrolytically may be subjected in whole or in part to any number of successive chemical treatments, and electric current applied to all or part of the treated material before, during, or after any stage or stages of the treating process, in order to produce various multicolor effects.

It is also to be understood that the term facsimile as used herein is intended to involve not only the reproduction on the recording material of a pre-existing subject, for example a photograph which is scanned and reproduced in accordance with the impulses emanating from the scanning operation, but also embraces the recording of subject matter in the process of creation or formation without a, physically pro-existing subject. As illustrative of this latter category would bethe recording of simply a mental preconception, for example a pattern or design, either of a single color and shades thereof, or multicolors, which is recorded in accordance with an appropriate manual or automatic variation of the electric impulses delivered to the electrodes. Similarly in this category is intended the recording of an arbitrary or haphazard design, pattern or other subject, for example one secured by haphazardly or arbitrarily varying electric impulses delivered to the electrode by punching keys on a master keyboard having suitable electrical connections, by manually or automatically varying resistance, or the like.

Having described the invention, what is desired to be secured by Letters Patent is:

1. The method of electrolytically producing quinoneimine dyes on a fibrous sheet material which comprises treating said sheet material with an aqueous solution containing a sufficient amount of a water-soluble inorganic salt as the electrolyte to facilitate the passage of the electrolyzing current, and a sufficient amount of an aromatic para-diamine and an aromatic compound having an unsubstituted ring position para to a group selected from the class consisting of amino and hydroxyl groups to form a quinoneimine dye upon oxidation and eifecting anodic oxidation and coupling of said aromatic paradiamine and said aromatic compound having the aforesaid unsubstituted ring position with the attendant formation of a quinoneimine dye by subjecting said fibrous sheet material to the action of an electrolyzing current.

2. The method of producing facsimile records on a fibrous sheet material in response to electrical signal variations which comprises treating the fibrous sheet material with an aqueous solution containing a sufficient amount of a watersoluble inorganic salt as the electrolyte to facilitate the passage of the electrolyzing current and a sufficient quantity of an aromatic para-diamine and an aromatic compound having an unsubstituted ring position para to a group selected from the class consisting of amino and hydroxyl groups to form a quinoneimine dye upon oxidation, and effecting anodic oxidation and coupling of said aromatic para-diamine and said aromatic compound having the aforesaid unsubstituted ring position with attendant quinoneimine dyestufi formation by subjecting the fibrous sheet material to the action of an electrolyzing current applied in accordance with the received signal variations.

3. The process as defined in claim 1 wherein the aromatic para-diamine is para-amino-dimethylaniline hydrochloride and wherein the aromatic compound having an unsubstituted ring position para to a group selected from the class consisting of amino and hydroxyl groups is meta-phenylene diamine hydrochloride.

4. The process as defined in claim 2 wherein the aromatic para-diamine is para-amino-dimethylaniline hydrochloride and wherein the aromatic compound having an unsubstituted ring position para to a group selected from the class consisting of amino and hydroxyl groups is meta-phenylene diamine hydrochloride.

5. A fibrous sheet material for the electrolytic formation of quinoneimine dyestuffs carrying a composition capable of producing quinoneimine dyes by anodic oxidation when subjected to the action of an electrolyzing current and containing as its essential components a sufficient amount of a water soluble inorganic salt as the electrolyte to facilitate the passage of the electrolyzing current and a sufiicient quantity of p-amino-dimethylaniline hydrochloride and m-phenylene diamine hydrochloride to form a quinoneimine dye upon oxidation.

NELLIE W. SOLOMON, Administratria: of Estate of Myer Solomon, De-

ceased.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 168,466 Edison Oct. 5, 1875 761,310 Loeb May 31, 1904 1,844,199 Bicknell et al Feb. 9, 1932 1,880,449 Hickmen et al Oct. 4, 1932 1,892,099 Cornell Dec. 27, 1932 (Other references on following page) Number Red 14,824

Number Number 10 16,189 17,241 21,634 536,506 28,923

Name Date Basch -1- June 2, 1936 Weyde et a]. June 16, 1942 Albers et a1. Jan. 26, 1943 Green May 31, 1910 Fletcher July 7, 1914 FOREIGN PATENTS Country Date Great Britain 1907 Great Britain 1905 Great Britain 1904 Germany Oct. 23, 1931 Netherlands 1 Feb. 15, 1933