US2873671A - Copy process and materials for use in same - Google Patents

Description

COPY PROCESS'AND MATERIALS FOR USE IN SAME Robert T. Florence, Park Ridge, 111-, assignor to A. B.

Dick Company, Niles, lll., a corporation of Illinois No Drawing. Application May 11, 1955 Serial No. 501,739

15 'Claims. (Cl. 101-4494 This invention relates to a multiple-copy process and to materials for use in the practice thereof. More particularly, it relates to an improvement in the invention described and claimed in my copending application Serial No. 287,616, filed May 13, 1952, now Patent No. 2,748,024.

It is an object of this invention to provide a new and improved multiple-copy process for use'in the field of ofiice copy work, and to provide elements for use in same.

More particularly, it is an object of this invention to provide an improvement in a copy process of the type described in my copending'application Serial No. 287,616 wherein a master imaged with a composition containing a water-and-alcohol soluble component of an azo dye isbrought into surface contact with copy sheets which have previouslybeen wetted with a solvent for the dye-forming component for leaching some of the dye-forming component for transfer from theimaged portion of the master tocorrespondingareas of the copy sheet and in which the copy sheet is provided with a component whichcauses reaction of the dye-forming component'upon transfer to form the dyestufis, and it is arelated objectto produce new and'improved materials-for use in same.

In theprcferred concept of the invention described and claimed in theaforementioned copendingapplication, a

diazo compound and-a coupler for reactiontherewith' are both contained in' a non-coupling-state in the transfer coating of a carbon sheet or mother-compositions for usein. the preparationv of animaged master; In the concept describednthe. diazo compound is 'stabilized against'reactionwith the coupler by'conversion'to a' diazonium' salt and/or. by adjustment .to maintain acidic conditions,"

as,b.eloW-a"pH"of 3.5 to prevent coupling. The fluid which is used to wet thesurfaces of the copy sheetsprior to contact with the imagedmasteris' :formed of a solvent for the stabilized diazo compound and coupler and contains a basic medium which, upon leaching of the diazo and couplerfrom the imaged master for transfer to' the copy esses.

2,873,671 Patented el). 7 i7, i959 In the system of the aforementioned copending application, the only time that a dyestuif isformed is in the copy sheets after they have been passed through the duplicating machine, and the dyestuifwhich is formed at this stage can be an insoluble dyestuff as distinguished from the highlywater-and-alcohol soluble dye of which the copy is formed in conventional spirit duplicating 1 systems.

Elimination of the dirtiness characteristic of conventional spirit duplicating or hectograph systems is achieved without sacrifice in the simplicity of the copy process, without sacrifice in the ease of "preparation of the imaged master or in the correction or modification of-the imaged master, and in the use of the imaged master to produce copies, or in the number of copies of good quality that can beproduced.

It has now been found, by way ofa still further improvement, that the character ofthe copy and the stability of the transfer sheet and the master imaged therefrom can be greatly improved when, instead of making use of a coupler and a stabilized diazo compound as separate components in the imaging compositiomuse is made of a complexcompound in the from of a diazo salt of a coupler formed by a non-couplingreaction of the diazo compound with the coupler in acidic medium.

Thesalt that is formed is sufiiciently soluble in the 'spirit fluids formed of alcohol and/ or a mixture of alcopresent in the image on the'surface of the master can be leached for transfer from the imaged areas of the master to corresponding areas of the copy sheets. If the fluid applied to the surface of the copy sheets contains a base, such as diethanolamine, monoethanolamine, or other organic base amines, sodium hydroxide, ammonium hydroxide or the like inorganic bases, or if the copy sheets contain a base or alkali incorporated therein, as during manufacture or by application subsequent to manufacture, or if the copy sheets onto which the salt has been leached from the master for transfer to the copy sheets are subsequently wet with a second. fluid containing. a base or alkali in solution, the adjustment of pH toward the alkaline side is sufiicient to initiate coupling reaction between the components of the saltto form the corresponding azo dyestufi or monoazo dye.

A number of very important and-distinct advantages and improvements are achieved by the use of the couplerstabilized salt instead of thecoupler and stabilized diazo compound as separate components, as in the process described in the copending application. From the standpoint of shelf life, and conditions of use in storage, the

coupler-stabilized diazo salt employed in the practice of this invention enjoys considerably'greater stability as compared to the system wherein use is made of a stabilized diazo compound as a component separate and apart from the coupler. As a result, the coupler-stabilized diazo salt or the diazo salt of the coupleris capable of storage over extended periods oftime and under differing atmospheric conditions without destruction or decomposition, and its resistance to decomposition and light is also greatly improved thereby markedly to enhance the service condi tions and life or the ,imagingcomposition, the transfer sheets formed thereof, and theimaged master.

More important from. the standpoint. of the .copy process itself, it has been found that the presence of the diazo and coupler in a single compound in the ratio in which they react to form the dyestutf insures intimate contact and immediate availability of the components necessary for reaction to form the dyestuff in the copy sheets. As a result, reaction takes place more quickly and more completely, and full use is made of all the diazo and coupler in dye formation to produce copy.

Still more important from the standpoint of the character of the copy and the intensity of the copy produced, as well as the number of copies available, is the fact that the presence of the diazo and coupler in a single compound militates against the extraction of one component in greater amounts than the other. In the system wherein the diazo is present in an imagining composition as a compound separate and apart from the coupler, the more soluble component, such as the coupler, is usually extracted in greater amounts than the other with the result that less copy is produced, and the copy is of inferior quality. By way of illustration, it may be assumed in a process of the type described in the aforementioned copending application that the coupler is more soluble in the fluid than the diazo compound. If the coupler and diazo are present in substantially equal proportions in the imaging material, then the fluid on the surface of the copy sheets brought into contact with the imaged master will tend to leach larger amounts of coupler than diazo from the image. While this may result in the production of copy of high intensity at the start, soon the image, or at least the surface portion thereof, will become exhausted or depleted of coupler, with the result that the intensity of copy produced will diminish greatly before all or even a good part of the diazo compound has been employed. As a result, any fraction of the diazo compound will be used, and an equally large fraction of the coupler will be wasted. The number of copies of good quality produced Will be less than the amount that should have been produced in proportion to the fraction of diazo which remains unused or inadequately used in the imaged master.

If, on the other hand, the ratio of coupler to diazo is increased in the imaging material to compensate for the greater solubility and preferential extraction of the coupler, the concentration of the essential dye-forming components in the imaged master will of necessity he reduced. This will result not only in reduction in the number of copies that can be made available, but the intensity of the copies produced throughout the run will be similarly diminished.

When, however, in accordance with the practice of this invention, the diazo and coupler are present as a single stabilized soluble compound, one equivalent weight of diazo will be removed with one equivalent weight of coupler. As a result, a maximum amount of the dye-forming components may be embodied in the imaging material. Only the amount of coupler necessary for reaction with the diazo will be leached with the diazo from the imaged master for use in production of the dyestuff.

Relatively little, if any, unused diazo Wiilremain in the imaging material Without an equivalent amount of coupler present for reaction therewith to form the monoazo dye. As long as the rate of solution is controlled and remains substantially uniform, the intensity of copy will have very little variation from beginning of the run to the end. Full utilization can be made of the dye-forming components formulated in higher concentrations in the imaging material thereby greatly to increase the number of copies of good quality that "can be produced. As previously pointed out, the coupler and diazo are so intimately associated together in the compound that the coupling reaction takes place substantially completely and immediately upon adjustment of the pH to form the dyestuff in the copy sheets. These and other advantages are available in the practice of this invention.

The coupler-stabilized diazo compound can be prepared by combining an alkaline solution of the sulfonic acid coupler compound with an acid solution of the diazo in which sufiicient free acid is available to more than neutralize the free alkali in the solution of the coupler to form a mixture having a weakly acid pH, such as in the range of 6.0-6.5. By way of example, l-naphthol-S amino-3,6 disulfonic acid (mono sodium salt) in alkaline solution can be added slowly to p-diazo dimethyl aniline to form the p-diazo dimethyl aniline salt of l-naphthol-S amino-3,6 disulfonic acid. 2,3 dihydroxy naphthalene-6 sulfonic acid in alkaline solution can be combined with p-diazo diethyl aniline to form the p-diazo diethyl aniline salt of the 2,3 dihydroxy naphthalene-6 sulfonic acid.

The 2,3 dihydroxy naphthalene-6 sulfonic in alkaline solution can be combined with an acid solution of p-diazo-N ethyl-N hydroxy ethyl aniline to form the p-diazo-N ethyl-N hydroxy ethyl aniline salt of 2,3 dihydroxy naphthalene-6 sulfonic acid. l-naphthol-8 amino- 3,6 disulfonic acid sodium salt in alkaline solution can be combined with p-diazo diethyl aniline in acid solution to form the corresponding p-diazo diethyl aniline salt of 1-naphthol-8 amino-3,6 disulfonic acid. l-naphthol-6 amino-3 sulfonic acid in alkaline solution may be combined with o-anisidine diazo in acid solution to form the corresponding o-anisidine diazo salt of l-naphthol-G amino-3 sulfonic acid. l-naphthol-S sulfonic acid in alkaline solution can be combined with o-anisidine diazo in acid solution to form the corresponding o-anisidine diazo salt of l-naphthol-S sulfonic acid.

As an example of the formation of a coupler-diazo salt, one molecular weight of a sulfonic acid coupler is dissolved in water at an alkaline pH. A separate acid pH solution is formed of an equivalent molecular weight of the diazo compound. The alkaline solution is added slowly to the acid solution with vigorous stirring to maintain a uniform mixture. The free acid content .in the second solution is preferably greater than the free alkaline content of the first by about ten percent. The volume of the two solutions can vary widely without changing the course of the reaction. The pH of the final solution will usually be below 7 and preferably within the range of 66.5 for best results, and the temperature should be held at about room temperature or lower. For a more detaled description of the reaction to form a corresponding salt, reference may be had to the U. S. Patent No. 2,525,75l.'

By way of illustration, but not by way of limitation, description will now be made of the preparation of a transfer sheet which makes use of the coupler-stabilizer diazo compound and the use of the transfer sheet in the preparation of an imaged master and in the production of copy therefrom.

Example I A carbon-type transfer sheet is formed by coating :1 thin'fibrous sheet of paper or the like with a composition compounded of the following materials:

11% by weight carnauba wax 15% by weight oxidized microcrystalline' wax 15 by weight heavy mineral oil 13% by Weight light mineral oil 1.5% by weight sodium oleate 44.5% (by weight coupler-stabilized diazo complex compoun The composition is heated to a temperature of about to C. for application as a hot melt onto the surface of the base sheet in concentrations ranging from 15 to 20 pounds per 3,000 square feet of surface area.

When applied as a hotsrnelty.thei compositionapplied? as a coating-to the surface of-....the base1sheet-remains as a substantially separated layeron .thesurfacetoform, a transfer coating capable of .displacement, onto materials in surface contact therewith responsive to the application of force.

naphthol-S sulfonic acid;-o-anisidine diazo-l naphthol-6- amino-3 sulfonic acid; 6 benzoyl amino-4 methoxy toluene-3 diazo salt of 1-naphthol-6"amino-3*sulfonic acid, or the like. coupler-stabilized diazo complexcompounds which are soluble in alcohol and water.

Example 11 vFor preparation of the imaged-master, the'coated carbon sheet manufactured inaccordance with Example I, ispositioned with the coated side at'surfacecontact with ,the prepared surface of a. suitable master, and the; coating is displaced from th'e carbon-sheet'to the master to form the mirror image in responseto forces applied against the uncoated side of the. carbon sheet, as by means of a stylus or other writing tool, typewriter key, die impression, or the like.

Instead of forming the image on the master sheet by transfer of portions of the'coating from the described carbon sheet, the image maybe-formed on the master sheet directly by printing or by the application of-a composition containing the coupler-stabilized diazo complex in a suitable carrier, such as when contained 1n a writing crayon, in a typewriter ribbon, or in a writing fluid or 111k.

Example III For the production commune copies, the imaged master prepared in accordance with Example II is mounted ona cylinder of a rotary duplicating machine of the conventional type used for spirit or hectograph processes. The fluid appliedto the surface of thecopy sheets in advance of contact with-the mastermay be formulated to contain the following;

12% by weight diethanolamine, 3% by weight Celloso1ve" by weight water 75% by weight-methanol As the :wetted, surfaceslof thecopy sheets are brought into surface contact with the imaged master' between the impression rollerand the-cylinder, some of the couplerstabilized diazo-complex is -,.'dissolved from the. surface portion of the image .and is transferre'dto'the .corre-i sponding areas of the copyJsheetwherethe diethanol amine functions to adjust the pHlevel'for effecting the coupling reaction to form .a .vvater insolublemonoazo dyestufi in direct image in the -.copy sheets, 7

From observation, it will become evident that the Instead of applying .the coating materials as a hot melt, the compositionmay be appliedfrom solvent solution or aqueous dispersionbyother dyestufif is formed in the copysheets as distinguished from theirnaged master, otherwisetransfer of .the coupled reaction product would bemorefdifiicult to achieve underthe conditions described and ,very faint,,if any, copy would result. Color development takesplace rather quickly once the COUPICIEStQbiliZfid diazo compouudhas been adjustedtoward the'alkaline side by the alkali me- 6 dillm: to form, the dyestufi. .Therapysheets--are-.capable of being handled: almost immediately; without fear? of? set-'ofi =orsmear, because. thecolor produced is rather permanent and substantially insoluble in character.

The number of copies secured depends: in part: upon, thethickness-of the coating of which the image is formed and the. amount of-coupler-stabilized. diazo compound contained in the coating composition, as well as the character and quantity-of fluidapplied to :the copysheets for effecting transfer'of thedye components from the imagedmaster forcoupling. to formthe dyestufi. -It--will be apparent, as previously described, that-the intensity of the color developed by the azo dye'will remain substantially. uniform throughout .the run :as long as :the amount of coupler-stabilized diazo compound that is. transferred remains substantially; the same. Under-.normalz-con'die. tions, the number of. copies produced by the practice of this invention is greater than that heretofore: secured by the process described in the '-aforementioned.cop endingapplication. From to 500 copies maybe secured. from ,a single master.

It is desirable-to embody ashigh a concentration ofthe: coupler-stabilizeddiazo compound as, possible-infi the imaging composition consistent with-the ability=of the coating to remainas a-film'for. forming the'image. Gen erally, the amount of dye-forming components introduced. as an ingredient in the coating composition depends upon the abilityto maintain sufiicient fluidity .under :thewon ditions existing in applyingthe coating to achieve -the-desired coverage. For the productionof a numberof'copiesof sufilcient intensity, it is desirable to-maintain the con centration of the coupler-stabilized diazocompound, in amounts in excess of 40% 'by weight, and preferably in amountsin excess of 60% by weight. When. theconcentration reaches as much as.80% by weight; the film-form, ing characteristics of theimaging material are reduced, unless modification ismadea-by the" addition of fluidizing,

agents.

When-appliedas a hot melt, or when applied from solvent solution or aqueous emulsion-it isfdesirable :to-secure acoating on the transfer sheet having a coating. weight withinthe range of .10 to,30 pounds1per 3,000 squarefeet of surface-area. 'When applied in solvent, solution with ethyl acetate, tri-chloroethylene,:and the like, alonev or in combination j with "diluents such -asv toluene orbenzene application may be made of the-coat;- ing composition present in amounts ranging from ,20% to 40% solids by weight, or the compositionmaybe formulated'into an-aqueous dispersion containing 5.40% to 60% by weight solids.

Instead of the fluidemployed in ExampleIILuse may bernade of other fluids embodying the following compositions.

Example IV Example V 2.0% by weight ammonium :hydroxide 98.0% .by Weight methanol V The following example provides for'thepr'oduction'of a red copy from an imaged duplicating master-z ExampZe VL Transfelr sheet composition g 7;

44.5 by weight 6'benzoyl amino-4 methoxy t'oluene- 3 diazo salt of l-naphthol-6 amino 3 *sulfonic acid (couplenstabilized diazo complex) 11.0% by Weight carnauba wax 15.0%by weight-oxidized microcrystalline was 28.0% by weight light mineral oil 1.5% 'by weight. sodium oleate Thef'above composition is reduced to a fluid; state by heating to a temperature of about 80-85 C. and then applied by a bolt melt coating process in' weights of about 20-30 pounds per 3,000 square feet of surface area onto a suitable base sheet whereby the applied coating composition remains concentrated on the surface of the base sheet for easy transfer therefrom upon cooling.

A master imaged with a transfer sheet prepared in accordance with Example VI may be used to produce red copy when the fluid applied to the surface of the copy sheets contains a base such as diethanolamine, monoethanolamine or the like.

It will be understood that the coupler-stabilized diazo complexes may be embodied in other suitable carriers such as combinations of oils in waxes wherein the oil components are present in higher concentrations to provide a liquid composition which may be inscribed to form the image on a suitable master sheet. Instead, the coupler-stabilized diazo complex may be embodied in a waxy system of the type which is applied on typewriter ribbons for transfer directly to the master to provide the irnage thereon from which copy may be produced.

It will be understood that changes may be made in the method of formulation and application in preparation of the imaging material to form the transfer coating on the carbon sheet or the image on the master, and that changes may also be made in the techniques for effecting transfer of some of the imaging material from the master to the copy sheets for the production of copy without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. A transfer medium for use in the preparation of an image duplicating master which is substantially free of color transfer value, comprising a base fabric and a composition present in transfer relation on said base fabric containing a coupler-stabilized diazo compound.

2. A transfer sheet for use in the preparation of an imaged duplicating master which is substantially free of color transfer value, comprising a paper base sheet and a continuous coating concentrated on the surface of the base sheet and capable of'substantially complete displacement therefrom containing a stabilized diazo salt of a coupler which is soluble in a medium selected from the group consisting of water and alcohol and containing a base. v r

3. A transfer sheet for use in the preparation of an imaged duplicating master which is substantially free of color transfer value, comprising a paper base sheet and a continuous coating concentrated on the surface of the base sheet and capable of substantially complete displacement therefrom formed of a wax base and containing a coupler-stabilized diazo compound.

4. A transfer sheet as claimed in claim 2 in which the stabilized diazo salt of the coupler is present in amounts ranging from 40-80 percent by weight in the coating composition.

5. A transfer sheet as claimed in'claim 2 in which the stabilized diazo salt of the coupler comprises a diazo salt of a sulfonic acid coupler.

6. A transfer sheet as claimed in claim 2 in which the stabilized diazo salt of the coupler is a stabilized compound selected from the group consisting of p-diazo dimethyl aniline-1 naphthol-8 amino 3,6 disulfonic acid; p-diazo diethyl aniline-2,3 dihydroxy naphthalene-6 sulfonic acid; p-diazo-N ethyl-N hydroxy ethyl aniline-2,3 dihydroxy naphthalene-6 sulfonic acid; p-diazo diethyl aniline-l naphthol-B amino-3,6 disulfonic acid; o-anisidine diazo-1 naphthol-S sulfonic acid; o-anisidine diazo-1 naphthol-6 amino-3 sulfonic acid, and 6 benzoyl amino-4 methoxy toluene-3 diazo salt of 1 naphthol-6 amino-3 sulfonic acid.

7. A composition for imaging a spirit duplicating master comprising a wax-oil base containing a coupler-stabilized diazo compound in the form of a diazo salt of a sulfonic acid coupler stabilized against reaction in acidic medium and which is soluble in a medium selected from the group consisting of water and alcohol.

8. A duplicating master comprising a master sheet comprising a waxy carrier and an image on the surface of the master sheet containing a coupler-stabilized diazo complex compound which is soluble in a medium selected from the group consisting of water and alcohol and containing a base.

9. A duplicating master as claimed in claim 8 in which the coupler-stabilized diazo complex compound is present in the imaging material in amounts ranging from 40-80 percent by weight.

I 10. A duplicating master as claimed in claim 8 in which the coupler-stabilized diazo complex compound is a diazo salt of a sulfonic acid coupler stabilized by formation in an acidic medium.

11. A duplicating master as claimed in claim 8 in which the coupler-stabilized diazo complex compound is a coupler-stabilized diazo salt selected from the group consisting of p-diazo dimethyl aniline-l naphthol-8 amino-3,6 disulfonic acid; p-diazo diethyl aniline-2,3 dihydroxy naphthalene-6 sulfonic acid; p-diazo-N ethyl N hydroxy ethyl aniline-2,3 dihydroxy naphthalene-6 sulfonic acid; p-diazo diethyl aniline-1 naphthol-8 amino 3,6 disulfonic acid; o-anisidine diazo-l naphthol-S sulfonc acid; o-anisidine diazo-1 naphthol-6 amino-3 sulfonic acid, and 6 benzoyl amino-4 methoxy toluene-3 diazo salt of 1 naphthol-6 amino-3 sulfonic acid.

12. The method of producing copy by spirit duplication with a master imaged with a material containing a large proportion of a coupler-stabilized diazo complex compound lacking in color transfer value and which is incapable of coupling reaction without adjustment of pH, comprising contacting the imaged surface of the master with copy sheets wetted with a fluid containing a solvent for the coupler-stabilized diazo complex compound and a compound for adjustment of the pH to a level where reaction can take place between the coupler and diazo components of'the compound to form the corresponding azo dyestufl whereby some of the couplerstabilized diazo complex compound transfers from the imaged areas of the masterto the copy sheet upon contact where reaction takes place to form the azo dyestuff.

13. The method of producing copy by spirit duplication with a master imaged with a composition containing a large proportion of a coupler-stabilized diazo complex compound substantially free of any color transfer value and which remains non-coupling until adjustment of pH to a higher pH level, comprising contacting the imaged master with a copy sheet wetted with a fluid containing a solvent for the coupler-stabilized diazo complex compound and a base for adjustment of the pH to a level where coupling reaction can take place between the diazo and coupler components of the compound to form the azo dyestuff whereby some of the coupler-stabilized diazo complex compound, transfers from the imaged areas of the master to the copy sheetwhere reaction takes place to form the azo dyestuif.

14. The method. of producing copy comprising'the steps ,of imaging a master with a composition substantially free of any dye color and containing a high proportion of a coupler-stabilized diazo complex compound soluble in a medium selectedfrom the group consisting of alcohol and water, wetting the surface of a copy sheet with a fluid containing a solvent for. the coupler and a base for adjusting the pH to permit coupling reaction between the diazo and coupler components of the compound, contacting the wetting copy sheet with the imaged surface ofthe master to effect transfer of some of the imaging material from the copy sheetwhere reaction takes place to form the azo dyestufi.

1 5. The rnethod,of producing copy, comprising the steps of imaging a master'with a composition substantially free of any dye color and containing a high proportion of a coupler-stabilized diazo complex compound which is non-coupling until adjustment of the pH, wetting the surface of a copy sheet with a fluid containing a solvent for the coupler-stabilized diazo complex compound and a medium for adjusting the pH to permit coupling reaction between the diazo and coupler components of the compound to form the corresponding azo dyestuff, contacting the wetted copy sheet with the imaged surface of the master to leach some of the couplerstabilized diazo complex compound for transfer from the imaged master to the copy sheet where reaction takes place upon pH adjustment to form the azo dyestufi therein.

References Cited in the file of this patent UNITED STATES PATENTS Thorpe Sept. 25, Dreyfus et a1. Sept. 29, Neidich Feb. 14, Neidich Oct. 8, Spoeni et a1. Oct. 10, Holik May 29, Yutzy et al. May 13, Klimkowski et al Apr. 14, Klimkowski et a1 May 29,

Claims (1)

12. THE METHOD OF PRODUCING COPY BY SPIRIT DUPLICATION WITH A MASTER IMAGED WITH A MATERIAL CONTAINING A LARGE PROPORTION OF A COUPLER-STABILIZED DIAZO COMPLEX COMPOUND LACKING IN COLOR TRANSFER VALUE AND WHICH IS INCAPABLE OF COUPLING REACTION WITHOUT ADJUSTMENT OF PH, COMPRISING CONTACTING THE IMAGED SURFACE OF THE MASTER WITH COPY SHEETS WETTED WITH A FLUID CONTAINING A SOLVENT FOR THE COUPLER-STABLIZED DIAZO COMPLEX COMPOUND AND A COMPOUND FOR ADJUSTMENT OF THE PH TO A LEVEL WHERE REACTION CAN TAKE PLACE BETWEEN THE COUPLER AND DIAZO COMPONENTS OF THE COMPOUND TO FORM THE CORRESPONDING AZO DYESTUFF WHEREBY SOME OF THE COUPLERSTABILIZED DIAZO COMPLEX COMPOUND TRANSFERS FROM THE IMAGED AREAS OF THE MASTER TO THE COPY SHEET UPON CONTACT WHERE REACTION TAKES PLACE TO FORM THE AZO DYESTUFF.