US3284201A

US3284201A - Three layered light-sensitive diazotype material

Info

Publication number: US3284201A
Application number: US245644A
Authority: US
Inventors: Meijs Jan Cornelis; Heuts Louis Bernard; Dohmen Jozef Maria Martinus
Original assignee: Grinten Chem L V D
Current assignee: Chemische Fabriek L Van der Grinten NV
Priority date: 1961-12-21
Filing date: 1962-12-19
Publication date: 1966-11-08
Anticipated expiration: 1983-11-08
Also published as: BE626167A; SE302406B; NL272831A; CH434974A; DE1251655B; GB983799A; ES283593A1

Description

United States Patent 3,284,201 THREE LAYERED LIGHT-SENSITIVE DIAZOTYPE MATERIAL Jan Cornelis Meijs, Louis Bernard Heuts, and Jozef Maria Martiuus Dohmen, all of Venlo, Netherlands, assignors to Chemische Fabriek L. van der Grinten N .V., Venlo, Netherlands No Drawing. Filed Dec. 19, 1962, Ser. No. 245,644 Claims priority, application Netherlands, Dec. 21, 1961, 272,831 16 Claims. (Cl. 96-75) The invention relates to diazo materials and more particularly to heat-developable two-component diazotype material.

The conventional two-component diazotype material is generally developed with the aid of ammonia vapour. This developing method is applied on a large scale, but it has disadvantages which make the application of the two-component diazotype process inconvenient in many cases, for instance .in otfices.

Special two-component diazotype materials have been proposed which can be developed without ammonia vapour, but solely by heating. Thus materials have been described of which the light-sensitive layer contains a substance which evaporates or decomposes upon heating, in consequence of which the pH in the light-sensitive layer increases to a value at which coupling of the diazo ctlumpound and the azo coupling component can take p ace.

Such diazotype materials either have poor keeping qualities, for instance because with a view to achieving the required developing speed the pH of the light-sensitive layer has been set too high or the layer has been stabilized insufficiently, or they cannot be developed at a temperature sufficiently low to be acceptable in practice, which is the case, for instance, if the substance elfecting the development is asubstance which splits off ammonia upon heating, such 'as urea, thiourea, and their alkyl derivatives. Developing temperatures of, for instance, 150 C. and higher are not desirable. If the copies are heated to such a high temperature they become brittle or they are scorched; moreover a large part of the diazo compound available for the formation of 'azo-dyestuff decomposes by pyrolysis, so that only weak azo-dyestulf images are obtained. In this connection it has to be observed that the temperature of the copies during development should not be confused with that of the developing device. The latter usually has a considerably higher temperature.

A summary of known processes and materials was published in Photographic Science and Eng, vol. 5, No. 4, July-August 1961, pages 239-243.

British patent specification 815,005 describes a heatdevelopabl'e diazotype material in which the diazo compound and the azo coupling component are present in separate layers, which are separated by a wax layer melting between 60 and 70 C. The latter is formed from molten wax. If necessary a top layer consisting of a film-forming organic binding agent can be applied. The diazo compound preferably is a very actively coupling and thus not particularly stable diazo compound, such as a 4-(4'-tolyl)mercapto-Z,5-diethoxybenzene diazonium salt or a 4-benzoylamino-2,S-diethoxybenzene diazonium salt. As suitable azo coupling components the actively coupling compounds resorcinol, phloroglucinol, and dimedone are mentioned.

Such diazotype material has good keeping qualities only if the waxy layer is thick. However, it then develops slowly and incompletely, because, upon heating, the azo coupling component has to dissolve in the molten waxy intermediate layer before penetrating into the diazo layer. All this has to take place during the time which is availice able for development and which, if pyrolysis of the diazo compound is to be avoided, can only be very short.

In order to increase the speed and the completeness of the development, the layer containing the azo coupling component may also contain a basic-reacting substance, for instance an amine of a long chain hydrocarbon such as steary-lamine.

In the presence of amines, however, some of the more commonly used azo coupling components, including phloroglucinol and resorcinol, form coloured oxidation products with the oxygen from the air. These oxidation products aifect the light-transmittance and the shade of the azo coupling component layer unfavourably. Moreover, the content of azo coupling component in the layer, and consequently also the completeness of the development, is decreased. Furthermore for diazotype material which is produced in the manner described in this patent specification it is not possible to use as support the conventional white base-paper for the diazoty-pe process, since this is transparentized by the molten wax item which the intermediate layer is formed.

In French patent specification 1,255,950 a similar heatdevelopable diazotype paper is described, in which an azo coupling component-containing layer, a wax layer, and a diazo layer are successively applied on a paper support. The azo coupling component-containing layer contains an "actively or very actively coupling azo coupling component, such as 2,3-dihydroxynaphthalene, or an azo coupling component of the pyrazolone or acetylacetanilide type with a low melting point. Furthermore it contains a hydrophilic binding agent, such as polyvinyl alcohol, and, if necessary, a basic-reacting substance such as hexylamine, laurylamine, and stearylamine. In this layer polyvinyl acetate may also be present.

The intermediate layer mainly consists of waxy mate- 'rial, such as paraffin and polyethylene, applied on the azo coupling component layer from an emulsion or an aqueous dispersion. It contains a hydrophilic binding agent, such as polyvinyl alcohol, and melts when the diazoty-pe paper is heated to above C.

The light-sensitive layer contains a diazo compound p-diazo-N,N-dimethylaniline, a slowly coupling stable diazo compound, and an acid the first dissociation constant of which is greater than 10- such as maleic acid or sulphamic acid. To avoid premature coupling, a fairly large quantity of such a strong acid has to be used. Moreover, the waxy intermediate layer still has to be rather thick, so that also with this material the development proceeds comparatively slowly, i.e. if the diazotype material is to be developed as satisfactorily as possible, it has to be kept at an elevated temperature for a long time. However, unless the content of diazo compound in the light-sensitive layer is high, it yields azo-dyestuff images which are not very dense, due to the pyrolysis of the diazo compound then occurring.

It is a further disadvantage of the use of intermediate layers of waxy material, as described in British patent specification 815,005 and French patent specification 1,255,950, that upon development the diazo compound is laterally displaced by the molten waxy material. There is, in consequence, a tendency to the formation of blurred images.

The present invention is concerned with the production of heat-developable diazotype material, which avoids the disadvantages referred to above.

According to the present invention there is provided a process for the production of heat-developable twocomponent diazotype paper which contains a light-sensitive benzene diazonium compound, an azo coupling component, an acid-reacting compound, a quantity of water of the order of that commonly used in twocomponent 3 diazotype material, and a fusible acid-neutralizing material, the latter material being separated from the layer which contains the diazonium compound by means of an intermediate layer, said process being characterized in that the paper is coated successively with:

(1) an open-structure light-sensitive layer containing, in addition to the diazonium compound, the azo coupling component, and the acid-reacting compound, a quantity of 1-6 g./m. of a thermoplastic, high-molecular, polymerized substituted vinyl compound, which is applied from an aqueous dispersion;

(2) A thin hydrophobic thermoplastic film layer, having a weight not exceeding 4 g./m. which layer separates the acid-neutralizing material from the light-sensitive layer, but transmits this material upon heating, and in which layer is present a polymeric substance selected from hydrophobic polymerized substituted vinyl compounds and hydrophobic cellulose derivatives, said film layer being formed on the dry light-sensitive [layer from a solution of the polymeric substance in a solvent in which the diazonium compound, the azo coupling component, and the acid-reacting compound present in the lightsensitive layer do not dissolve, or only slightly so; and

(3) A light-transmitting layer which is dry and solid at room temperature and which contains a filler as well as an acid-neutralizing organic material melting below 100 C. and selected from non-volatile or only slightly volatile organic non-aromatic amines and the salts of those amines with weak acids.

The invention also relates to heat-developable twocomponent diazotype paper, which is produced by the above-mentioned method. By means of the invention, heat-developable two-component diazotype paper can be produced which has good keeping qualities under normal atmospheric conditions, and copies on this material can be developed within a few seconds by heating to a temperature not exceeding 120 C., strong azo-dyestuff images thus being formed.

-It is one of the characteristic qualities of heat-developable two-component diazotype paper according to the invention that the diazo compound and the azo coupling component are present in one layer together with a quantity of an acid or an acid-reacting substance necessary for preventing decomposition of the diazo compound and premature coupling of the-diazo compound and the azo coupling component. This layer can be regarded as a normal two-component diazotype layer, which, if desired, can indeed also be developed with the aid of ammonia vapour. The paper according to the invention can therefore be developed in two different ways, which may be an advantage for users who already have apparatus for ammonia-development at their disposal, for instance in a drawing office, and who set up a heat-developing machine in the general office, but wish to use the same paper in the two departments.

For development with ammonia vapour, the diazotype paper of this invention is preferably placed in such a way that its back is turned to the source of ammonia, because the paper support will generally have greater transmission for ammonia vapour than the combination of layers applied on the light-sensitive layer.

The structure of the light-sensitive layer of the diazotype paper a-ccording to the invention has to satisfy certain special requirements as compared with normal two-component diazotype paper. Thus, upon development by heating, the liquid acid-neutralizing organic material has to penetrate via the intermediate layer into the light-sensitive layer, where it has to neutralize the acid-reacting compound present therein, in order to effect the azo-dyestuff formation. The lightsensitive layer has to be permeated with the acid-neutralizing material within a few seconds, because otherwise pyrolysis of the diazo I ture and preferably should be present on the surface of the support as a very thin separate layer.

This desired condition may not be obtained, for instance, if the diazo compound and the azo coupling component have penetrated between or into the fibres of the paper support. The support used therefore is preferably paper which has been pre-coated with a so-called surfaceimproving agent, such as colloidal or non-colloidal silica or aluminium oxide or titanium dioxide or baryta (colloidal), clays such as kaolin, bentonite, zeolite, attapulgite, halloysite and the like, or synthetic resins such as polystyrene, polymethylmethacryl-ate, polyvinyl acetate, butadiene-acryl-onitrile copolymers, vinylidene chloride copolymers and the like, or paper which has been lacquered, for instance, with a cellulose acetate lacquer. If desired and if possible, the surface-improving agent may also be added to the sensitizing liquid.

In order to give the light-sensitive layer the desired open structure, a quantity of a finely divided thermo-' plastic, high-molecular, polymerized substituted vinyl compound is incorporated in this layer from an aqueous dispersion. Preferably an acid aqueous dispersion of such a polymer is added to the aqueous sensitizing liquid with the aid of which the light-sensitive layer is formed. It is also possible, however, to apply the dispersion before or after sensitization.

In principle the acid aqueous dispersions of many thermoplastic, high-molecular, polymerized substituted vinyl compounds can be used. Preferably use is made of polymers the particles of which soften and adhere together upon the application of heat sufiicient to dry the surface that has been treated with the polymer containing liquid. Polymers the particles of which do not have this quality can be given this quality by addition of plasticizer. The particles of such polymers, however, may alternatively be fixed to the paper surface with the aid of a binding agent such as polyvinyl alcohol.

The polymer, however, must not be markedly adhesive or form a closed film on the paper surface, both of which are qualities of polymers with a relatively low molecular weight \and/ or high content of plasticizer.

Polymerized substituted vinyl compounds which are suitable for use in the light-sensitive layer and can be incorporated therein from an acid aqueous dispersion are, for instance, high-molecular polyvinyl acetate, polystyrene, polyvinyl chloride, high-rnolecular copolymers of vinyl acetate with vinyl chloride and of styrene with butadiene, polymethylmethacrylate, polybutylmethacrylate, copolymers of vinylidene chloride, and copolymers of vinyl chloride with vinyl isobutyl ether.

Preferably dispersions with an average particle size between 05 and 3 microns are used. Useful results can also be obtained with finer dispersions. Thus dispersions of polymers which soften at relatively high temperatures, such as polystyrene, the average particle size of which 1s about 0.1 micron, can be used, although light-sensitive layers which are formed with such dispersions are less readily accessible to the acid-neutralizing material penetrating through the intermediate layer upon development than are light-sensitive layers in the formation of which coarser dispersions have been used. In the case of polymers With a low softening point, such as polyvinyl acetate, finer dispersions (with an average particle size smaller than 0.5 micron) are much less suitable, because a light-sensitive layer formed with them often does not have the desired open structure. A light-sensitive layer in which a polymer from an aqueous dis-persion with an average particle size of more than 3 microns has been incorporated often has a structure that is too rough and too open, in consequence of which it is difficult to form a thin intermediate layer on such a layer. The best results are obtained with aqueous dispersions of polymers with an average particle size of about 1 micron.

The quantity of polymer which the light-sensitive layer should contain, in order that it should possess the desired structure lies between 1 and 6 g. of polymer per m? of sensitized surface. Quantities smaller than 1 g./m. are not very effective, whilst quantities of more than 6 g. cause the light-sensitive layer to become too thick. In both cases the development proceeds too slowly and relatively weak azo-dyestuff images are obtained. Usually quantities of 2 to 4 g./m. are chosen.

On the light-sensitive layer a thin hydrophobic thermoplastic film layer is applied. This layer separates the acid-neutralizing organic material from the light-sensitive layer, even when the diazotype material is kept under unfavourable conditions, for instance in warm moist surroundings. However, upon development it permits the passage of that material.

Polymers which are suitable for the formation of the intermediate layer include the non'crystallizing and the non-waxy, hydrophobic, polymeric substituted vinyl compounds, for instance polyvinyl acetates, polyvinyl acetals, polyvinyl butyrals, polystyrenes, polymethylmethacrylates and copolymers thereof, polybutylrnethacrylates, and copolymers of vinyl acetate with vinyl chloride, and cellulose acetates, cellulose acetate butyrates, benzylcelluloses, and ethylcelluloses. Mixtures of these polymers may also be used.

The solution from which the intermediate layer is formed preferably contains l-3% by weight of the poly mer in a solvent such as ethyl acetate, acetone, trichloroethylene, carbon tetrachloride, benzene, toluene or tetra hydrofur-an. The diazo compound, the azo coupling component, and the acid-reacting compound which are present in the light-sensitive layer, do not dissolve in these solvents or only slightly so, so that when the intermediate layer is applied, these substances remain in situ and are not mixed with the polymer from which the intermediate layer is formed. Mixtures of these solvents may also be used.

The intermediate layer may be of very small thickness. Layers of which the weight is considerably less than 0.5 g./m. can still afford good results. But their production calls for a very accurate working method, because, for instance, any impurity in the liquid from which such a layer is formed may cause an opening in the layer, through which the acid-neutralizing material may prematurely penetrate into the light-sensitive layer. Intermediate layers having a weight of more than 4 g./rn. cannot be used very well in practice, because the time which the acid-neutralizing material needs to penetrate through them upon development is too long. Very suitable intermediate layers are those having a weight of 0.3 to 1 g./m.

The acid-neutralizing organic material is present on the intermediate layer in a light-transmitting layer which is dry and solid at room temperature. It should be substantially non-volatile at temperatures below 140 C. and may consist of a substance that is solid at room temperature and has a low melting point. It may, however, also be liquid at room temperature. The non-volatile or slightly volatile organic non-aromatic amines and their salts with weak acids have been found to be very suitable. Examples of suitable amines are primary aliphatic amines with a long carbon chain, such as laurylamine, stearylamine, octamethylene diamine, decamethylene diamine; N-(alkylcarbonylamido)ethyl-N-ethanolamines having an alkyl radical of 6-18 C-atoms; triethanolamine. Salts of such amines with weak acids, such as triethanolamine stearate and phosphate, are also suitable. Such salts may be formed in the solution or dispersion with the aid of which the layer containing the acid-neutralizing material is applied, for instance from a mixture of a salt of such an amine with a strong acid and a salt of a strong base with a weak acid, for instance from ttriethanolamine chloride and sodium stearate.

Amongst these substances the N-(alkylcarbonylamido) ethyl-N-ethanolarnines having an alkyl radical of 6-18 carbon atoms are preferred. Upon development they permeate quickly through the intermediate layer and they hardly evaporate at temperatures of l20-140 C.

In order to obtain a layer which is dry and solid at room temperature, which can readily be written on, and which is pleasant to the touch, the acid-neutralizing organic material is mixed with finely divided substances, herein referred to as fillers, such as silica, aluminium oxide, kaolin, titanium dioxide, barium sulphate, bentonite, magnesium carbonate, synthetic resin dispersions, for instance dispersions of polyvinylacetate, polyvinyl chloride, polystyrene, polymethylmethacrylate, and copolymers thereof.

Each of the different layers in the two-component diazotype paper according to the invention should have a uniform thickness and structure throughout its plane and should have good anchorage to the support paper and the adjacent layers. A preferred embodiment of the process according to the invention is that. in which the intermediate layer is formed from a solution of a suitable polymer in a solvent in which the polymer present in the light-sensitive layer swells or dissolves. quence, upon the formation of the intermediate layer, good adhesion of the polymer that is present in the said solution to the polymer in the light-sensitive layer is obtained, owing to which the two layers are firmly fixed together. In this process good results are always obtained if the two polymers are of the same kind or at least are chemically very closely related, provided, of course, that the dispersion from which the polymer in the lightsensitive layer is applied has been so chosen that the lightsensitive layer has the desired open structure. Thus, if the polymer in the light-sensitive layer is applied from an aqueous dispersion of polystyrene or poly-n-butylmethacrylate, and, if the intermediate layer is formed with a solution of polystyrene or with a solution of polymethylmethacrylate, in solvents such as trichloroethylene, ethyl acetate, and acetone, two-component diazotype paper according to the invention which has good keeping qualities and develops well at about 120 C. can be produced.

A good result is achieved if polyvinyl acetate is present either in the light-sensitive layer or in the solution from which the intermediate layer is formed, or in both. Thus, stable and rapidly developing two-component diazotype paper according to the invention can be produced if the intermediate layer is formed from a solution of polyvinylacetate in a solvent in which the polymer present in the light-sensitive layer swells or dissolves, such as ethyl acetate, acetone, carbon tetrachloride, trichloroethylene, benzene or toluene. Other polymers may also be present in the polyvinyl acetate solution. Instead of polyvinylacetate, copolyrners thereof can also be used. A solution of 13% by weight of polyvinyl acetate having a molecular weight of 500,000 or higher, preferably 1,000,000 or higher, in ethyl acetate, acetone or trichloroethylene is preferred. When polyvinyl acetate is used in the light-sensitive layer, the polyvinyl acetate dispersion has to meet the requirements stated above with reference to the polymer in the light-sensitive layer. Twocomponent diazotype paper according to the invention which has good structure and good anchor-age of the layers, and which develops rapidly and has good keeping qualities, is that in which the light-sensitive layer contains a quantity between 1 and 6 g./m. of finely divided polyvinyl acetate having a molecular weight of at least 500,000, applied from an acid aqueous dispersion the average particle size of which is between 0.8 and 3 microns, and the intermediate layer is a thin film layer having a weight not exceeding 4 g./m. consisting substantially of polyvinyl acetate with a molecular weight of more than 500,000 and covered with a light-transmitting layer which is dry and solid at room temperature .and contains a filler as well as an acid-neutralizing organic material melting below C. which is a non-volatile or only slightly volatile organic non-aromatic amine or a salt of such an amine with a weak acid. Very satis- In consefactory two-component diazotype paper according to the invention is also obtained if, using the said finely divided polyvinyl acetate in the light-sensitive layer the intermediate layer is formed with the aid of a solution of a polymer other than polyvinyl acetate, for instance of a hydrophobic cellulose derivative, such as cellulose acetate, cellulose acetate butyrate, ethylcellulose, benzylcellulose, or with the aid of a solution of polystyrene, polymethylmethacrylate, polyvinyl chloride, or copolymers thereof. In all these cases a solvent for polyvinyl acetate is used in which the diazo compound, the am coupling component, and the acid-reacting compound present in the light-sensitive layer do not dissolve.

The two-component diazotype paper according to the invention in which the polymer in the light-sensitive layer, or that in the intermediate layer, or both is or are polyvinyl acetate develops rapidly at temperatures between 100 and 130 C. and has good keeping qualities if the acid-neutralizing organic material is a water-soluble N-(alkylcarbonylamido) ethyl-N-ethanolamine the alkyl radical of which contains at least 6 carbon atoms.

In the heat-developable two-component diazotype paper according to the invention the light-sensitive diazonium compounds commonly used in the two-component diazotype process can be employed. Good results are obtained with benzene diazonium salts with a tertiary amino group in p-position, such as 4-diazo N,N-dimethylaniline, 4-diazo N,N-diethylaniline, 4-diazo N-ethyl N-2-hydroxyethylaniline and 4-diazo morpholinobenzene, and also with diazo compounds with a secondary amino group in p-position such as 4-diazo 2-rnethoxy N-rnethylaniline. During the time necessary for the development, these diazonium compounds are satisfactorily resistant to .temperatures of l-130 C. Surprisingly, the much less stable 4-diazo 2,S-dialkoxyphenylmorpholines, such as 4-diazo 2.,5-diethoxyphenylrnorpholine and 4-diazo 2,5-din-hutoxyphenylrnorpholine, can also be used with a good result. Apparently the quantity of these latter diazonium compounds converted in a few seconds at a developing temperature of 120 C. into azo-dyestutf is sufficient to obtain strong azo-dyestuff images. Because of their great light-sensitivity a larger quantity of these latter compounds can be used than of the first-mentioned compounds. Nevertheless the diazotype paper produced therewith is much more light-sensitive than the diazotype paper made with the first-mentioned compounds.

The azo coupling components which are commonly used in the two-component diazotype process, are eminently suitable for use in the heat-developable two component diazo-type material according to the invention. Examples are Z-hydroxynaphthalene, 2,3-dihydroxynapthalene, 2,3-dihydroxynaphthalene 6-sulphonic acid, 2,7-dihydroXynaphthalene-3,6-disulphonic acid, 1,6,7-trihydroxynaphthalene-3-sulphonic acid, 7-hydroxy-1,2, 4,5 naphthimidazole, 2 hydroxy 3 (2'hydroxy)ethylamido-carbonylnaphthalene, m-ureidophenol, 2,2,4,4'- diresorcinol, hydroxyethylamide of fl-resorcyclic acid, 4-di-methylamino methyl-2,S-dimethylphenol, dimedone and 1-phenyl-3-amido-carbonylpyrazolone-S. As in the normal two-component diazotype process, actively coupling azo coupling components such as phloroglucinol and resorcinol may be used in combination with relatively slowly coupling diazonium compounds, to avoid premature coupling, whilst slowly coupling azo coupling components such as 2-hydroxy-naphthalene-3,6-disulphonic acid and 7-hydroxy-1,2,4,S-naphthimidazole may be used with relatively actively coupling diazonium compounds.

The light-sensitive layer further contains a suflicient quantity of an acid-reacting compound, such as tartaric acid, citric acid, maleic acid, succinic acid, alum and the like.

It may also contain other auxiliary agents commonly used in two-component diazotype layers, for instance metal salts, such as zinc chloride, magnesium chloride and nickel sulphate; substances which increase the developing speed, such as glycerol, polyethylene glycol, urea, allylthiourea; stabilizers, such as thiourea and naphthalenel,3,6-trisulphonic acid or one of its salts; and substances which improve the shade of the azo-dyestuif formed upon development, such as 2-hydroxymethylbenzimidazole.

As in the conventional two-component diazotype material, the heat-developable two-component diazotype paper according to the invention should contain a small quantity of water in order to ensure good development.

The following examples will serve further to illustrate the invention:

Example I White base-paper of weight g./m. and suitable for the diazotype process, which has been pre-coated with an aqueous silica dispersion and dried, is sensitized with a liquid containing:

9 g. of 4-diethylamino'benzene diazonium chloride, zinc chloride double salt 7.5 g. of 2,3-dihydroxynaphthalene 15 g. of calfeine 3 g. of citric acid 450 ml. of the aqueous polyvinyl acetate polyvinyl chloride copolymer dispersion Appretan EM.

600 ml. of water and dried until the paper only contains about 3% by weight of Water. The light-sensitive layer contains about 3 g. of polymer per m.

On the dried light-sensitive layer an intermediate layer is formed by spreading on it a solution of:

30 g. of the high-molecular polyvinyl acetate Mowilith 70 (molecular weight about 1,000,000) in 1000 ml. of ethyl acetate and drying.

The intermediate layer weighs 0.5-0.7 g./m. Finally the material obtained is coated with a dry, solid, light-transmitting layer which contains acid-neutralizing material, by applying on the intermediate layer a layer of 10 to 15 g./m. of a liquid containing:

50 g. of stearylamine (melting point about 43 C.) 17 g. of non-colloidal silica (Syloid 244) 1000 ml. of petroleum ether and drying.

A sheet of the diazotype paper thus produced is imagewise exposed in contact underneath a transparent ink drawing until underneath the white portions of the drawmg all the diazo compound has bleached out, and is then developed by guiding it round a metal cylinder having a temperature of C., which cylinder rotates with a circumferential speed of about 1.5 m./min., while the sheet lies with its back against the cylinder and is in contact with the cylinder over a distance of about 10 cm. Every part of the sheet is thus heated for about 4 seconds.

The copy obtain-ed shows a strong violet-blue azo-dyestuff image on a clear white background. The image side of the copy can readily be written on with pencil, fountain-pen, and ballpointpen.

Copies on this diazotype paper can also be developed by exposure to ammonia vapour, the sheet to be developed being turned with the paper side towards the source of ammonia.

The diazotype paper has good keeping qualities.

Example 11 White base-paper of weight 80 g./m. and suitable for the diazotype process, which has been pre-co-ated with an aqueous dispersion of polyvinyl acetate and dried, is coated with a light-sensitive layer by treating it on the pre-coated side with a liquid containing:

16 g. of 4-morpholino-2,S-diethoxybenzene diazonium chlorlde, zinc chloride double salt and drying until the paper has a moisture content of 2 to 3%. The light-sensitive layer contains about 4 g. of polymer per m On the light-sensitive layer an intermediate layer is now applied by spreading on it a thin layer of a solution of:

30 g. of the high-molecular poylyvinyl acetate Mowilith 90 (molecular weight about 2,000,000) in 1000 ml. of trichloroethylene and drying. 1 g./m.

On the intermediate layer is applied a light-transmitting, dry, solid layer, which contains an acid-neutralizing organic material. To this end a thin layer of a liquid containing:

The intermediate layer weighs about 40 g. of the N-(alkylcarbonylamido) ethyl-N-ethanolamine Nalcamine A.12 (melting point 35 C.)

7 g. of non-colloidal Silica (Syloid 244) 250 ml. of the polyvinyl acetate dispersion Vinnapas H.60, and

1000 ml. of water is applied and dried.

A sheet of the highly light-sensitive diazotype material thus obtained is imagewise exposed until underneath the white portions of the original all the diazo compound has bleached out, and is then developed by guiding it round a metal cylinder having a temperature of 135 C., which cylinder rotates with a speed of about 1.8 m./min., while the sheet lies with its light-sensitive side against the cylinder and is in contact with the cylinder over a distance of 10 cm. Every part of the sheet is thus heated for about 3 and /3 seconds.

The copy obtained shows a strong violet-blue azo-dyestuif image on a white background. Development with the aid of ammonia vapour also yields a strong violet-blue azo-dyestuff image.

The diazotype paper has good keeping qualities.

Example III White base-paper of weight 80 g./m. and suitable for the diazotype process, which has been pro-coated with the aqueous butadiene-acrylonitrile copolymer dispersion Chemigum 245 CH8 and dried, is sensitized with a liquid containing:

6 g. of 4-morpholino 2,5-di-n-butyoxybenzene diazonium chloride, zinc chloride double salt 12 g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt 2 g. of tartaric acid 600 ml. of water 450 ml. of the aqueous polyvinyl acetate dispersion Vinnapas H60 and dried. The light-sensitive layer contains g. of polymer per m. The diazotype paper has a moisture content of about 2.5%.

The dry light-sensitive layer is treated with a solution of:

g. of the high-molecular polyvinyl acetate Mowilith 90 in 1000 m1. of trichloroethylene and then dried. Thus an intermediate layer is formed with a weight of about 0.3 g./m.

A dry, solid, light-transmitting layer is formed on the intermediate layer by application of a liquid containing:

45 g. of the N-(alkylcarbonylamido) ethyl-N-ethanolamine Nalcamine A12 60 m1. of the aqueous silica dispersion Satessa 14 300 ml. of water, and

600 ml. of a solution of 70 g. of the polyvinyl alcohol Mowiol 5098 in a mixture of 300 ml. of ethanol (96%) and 700 ml. of water,

and drying.

A sheet of the highly light-sensitive diazotype material thus obtained is imagewise exposed and developed as in Example I. It shows a strong dark-blue azo-dyestulf image.

The diazotype paper has reasonable keeping qualities.

Example IV White base-paper of weight 70 g./m. and suitable for the diazotype process, which has been pre-c-oated with an aqueous silica dispersion and then dried, is sensitized with a liquid containing:

9 g. of 4-N-2'-hydroxyethyl N-ethylaminobenzene diazonium chloride, zinc chloride double salt 9 g. of 2,7-dihydroxynaphthalene-3,6-disulphonic acid sodium salt 3 g. of boric acid 450 ml. of polyvinyl acetate dispersion Setamul N. 9125,

and

600 ml. of water,

and dried. The light-sensitive layer contains about 3 g. of polymer per m. The diazotype paper has a moisture content of about 4%.

On the dry light-sensitive layer a polyvinyl acetate intermediate layer is applied with the aid of a solution of:

30 g. of polyvinyl acetate Mowilith in 1000 ml. of trichloroethylene.

After drying, a thin film of polyvinyl acetate has been formed on the light-sensitive layer, which film firmly adheres to the light-sensitive layer. It weighs about 0.5 g./m. On the filmlike intermediate layer is applied a layer which contains an acid-neutralizing organic material, from a liquid containing:

30 g. of triethanolamine stearate 12 g. of non-colloidal silica (Syloid 244) 1000 ml. of water.

After the water has evaporated, a solid dry layer is left, which is not sticky.

A sheet of the diazotype paper thus obtained is imagewise exposed and developed as in Example II. The copy shows a violet image on a white background. Development with ammonia vapour also yields a violet image on a white background.

The diazotype paper has excellent keeping qualities.

Example V White paper of weight g./m. which is coated on one side with a cellulose acetate film layer (approximately 50% by weight of combined acetic acid) having a thickness of about 10 microns, which is fixed to the paper by means of an adhesive, is coated on the side of the cellulose acetate layer with a light-sensitive'layer by treatment with a solution containing:

10 g. of 4-morpholino-2,S-diethoxybenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 30 g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt 500 ml. of the polystyrene dispersion Polystyrene R 500 m1. of water and drying.

The light-sensitive layer contains about 2 g. of polystyrene per m? and about 2 g. of water per m.

On the light-sensitive layer an intermediate layer is ap- 1 1 plied by spreading on it a thin layer of a solution containing:

22.5 g. of the polyvinyl acetate Mowilith 70 7.5 g. of cellulose acetate of the type Hercules L.M.1 in 1000 ml. of acetone and drying.

On the intermediate layer, which weighs about 1 g./m. is applied the light-transmitting, dry, solid layer described in Example I, which contains an acid-neutralizing organic material.

A sheet of the highly light-sensitive diazotype material thus obtained is imagewise exposed and developed as in Example II. The copy obtained shows a violet-blue image on a white background. The diazotype paper has good keeping qualities.

Example VI White base-paper of weight 70 g./m. and suitable for the diazotype process, which has been pre-coated with the aqueous n-butyl-methacrylate dispersion Plextol P2n and dried, is sensitized with a liquid containing:

7.5 g. 4-methylamine-3-methoxybenzene diazonium chloride, zinc chloride double salt 15 g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt 2.5 g. of tartaric acid 750 ml. of the n-butylmethacrylate dispersion Plextol P2n 250 ml. of water and dried in the usual way.

The light-sensitive layer contains about 3 g. of polymer per m.

n the dry light-sensitive layer an intermediate layer of 3 g./m. is applied with the aid of a solution of:

30 g. of the polyvinyl acetate Mowilith 90 in 1000 ml. of acetone.

On the intermediate layer a dry solid layer, which contains-an acid-neutralizing organic material, is applied by treatment with a liquid containing:

31 g. of the N-(alkylcarbonylamido) ethyl-N-ethanolamine Nalcamine A.12

5.5 g. of non-colloidal silica 150 ml. of the polyvinyl acetate dispersion Vinnapas H60 850 ml. of water and drying.

A sheet of the diazotype paper thus obtained is imagewise exposed and developed as in Example I. The copy shows a violet-blue azo-dyestutf image on a white background.

The diazotype paper has good keeping qualities.

Example VII White base-paper of weight 70 g./m. and suitable for the diazotype process, which has been pre-coated with the aqueous polyvinylidene chloride copolymer dispersion Saran F. l22A.15 and then dried, is sensitized with a liquid containing:

g. of 4-morpholino-2,S-diethoxybenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt 600 ml. of the polyvinyl acetate dispersion Vinnapas H60 400 ml. of water and dried in the usual way.

The dry light-sensitive layer contains about 5 g. of polyvinyl acetate per m. On the light-sensitive layer an intermediate layer is applied by spreading on it a thin layer of a solution containing:

25 g. of the copolymer Plexigum M265 containing predominantly polymethylmethacrylate in 1000 ml. of acetone and drying.

Example VIII White base-paper of weight 70 -g./m. and suitable for the diazotype process, which has been pre-coated with an aqueous silica dispersion, is sensitized with a liquid containing:

, 10 g. of 4-morpholino-2,5diethoxybenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 30 g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt I 400 ml. of water 600 ml. of the n-butylmethacrylate dispersion Plextol P2n and dried in the usual way.

The dry light-sensitive layer contains about 4 g. of polymer per m.

With the aid of a solution of:

50 g. of the polyvinyl acetate chloride copolymer Vinnol HH 40 in 1000 ml. of trichloroethylene an intermediate layer, which after drying weighs about 2 g. per m is formed on the light-sensitive layer.

On the intermediate layer is applied the dry, solid, light transmitting layer described in Example III, containing acid-neutralizing organic material. A sheet of the highly light-sensitive diazotype paper thus obtained is imagewise exposed and developed as in Example I. The copy shows a strong violet-blue image on a white background.

The diazotype paper has reasonable keeping qualities.

Example IX White base-paper of weight 70 .g./m. and suitable for the diazotype process which has been pre-coated with an aqueous silica dispersion and dried, is sensitized with a liquid containing:

10 g. of 4-niorpholino-2,S-diethoxybenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 32 g. of 2,3 dihydroxynaphthalene-6-sulphonic acid sodium salt 400 ml. of water 600ml. of the polysnabutylmethacrylate dispersion Plextol and dried in the usual way.

On the dry light-sensitive layer, which contains about 4 g. of polymer per m. an intermediate layer is formed by treatment with a solution of 25 g. of the copolymer Plexigum M. 265 containing predominantly polymethylmethacrylate in 1000 ml. of acetone and drying, as a result of which an intermediate layer of about 1 g./m. is formed.

0n the intermediate layer is applied the top layer described in Example III, which contains an acid-neutralizing organic material.

A sheet of the highly light-sensitive diazotype paper thus obtained is imagewise exposed and developed as in Example I. A copy with a strong violet-blue azo-dyestuff l3 image on a white background is obtained, which copy can readily be written on.

Example X White -base-paper of weight 70 g./n1. and suitable for the diazotype process, which has been pre-ooa ted with an aqueous silica dispersion and dried, is sensitized with a liquid containing:

8 g. of 4-morpholino-2,5-diethoxybenzene diazonium chloride, zinc chloride double salt 16 g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt 4 g. of tartaric acid 400 ml. of water 600 ml. of the polystyrene dispersion Polystyrene R,

and dried in the usual way.

On the dry light-sensitive layer, which contains about 2 g. of polystyrene per m. an intermediate layer of about 1.5 g. is formed by treatment with a solution of:

25 g. of polystyrene in 1000 ml. of carbon tetrachloride and drying.

Then the layer described in Example III, which contains acid-neutralizing organic material, is applied on the intermediate layer.

A sheet of the satisfactorily light-sensitive diazotype paper thus obtained is imagewise exposed and developed as in Example II. The copy shows a violet-blue image on a white background.

Example XI White base-paper of weight 70 g./tm. and suitable for the diazotype process is sensitized with a liquid containing:

12 g. of 4-morpholinobenzene diazonium chloride, zinc chloride double salt 2 g. of tartaric acid 24 g. of 2-hydroxy-3-(,B-hydroxyethyl)amidocarbonylnaphthalene 48 g. of caffeine 400 ml. of water 600 'ml. of the acrylic polymer Rhoplex 13.15

and dried in the usual way.

On the dry light-sensitive layer, which contains about 3 g. of polymer per m. an intermediate layer of about 2 g. is formed with the aid of a solution of:

25 g. of the polyvinyl aoetal Alvar 1570 in 1000 ml. of trichloroethylene.

After drying, this intermediate 'layer is coated with a layer in which acid-neutralizing organic material is present, by treatment with a liquid containing:

35 g. of the N-(alkylcarbonylamido) ethyl-N-etha-nolamine Nalcamine A.l2

175 ml. of Vinnapas H.6O

6 g. of tbentonite Colclay 0023 900 ml. of water and drying.

A sheet of the diazotype paper thus obtained is imagewise exposed and developer as in Example I. The copy shows a violet-blue azo-dyestutf image on a white background.

Example XII White base-paper of weight 70 g./m. and suitable for the diazotype process, which has been pre-coated with an aqueous silica dispersion and dried, is sensitized with a liquid containing:

12 g. of 4-diethylamino-Z-ethoxybenzene diazonium chloride, zinc chloride double salt 2 g. of tartaric acid 14 24 g. of 2,3-dihydroxynaphthalene-6-sulphonic acid sodium salt 400 ml. of water 600 ml. of the polyvinyl acetate dispersion Setamul 9125 and dried in the usual way.

The dry light-sensitive layer contains about 4 g. of polyvinyl acetate per m. On this layer an intermediate layer of about 1 g./m. is formed by treating it with a solution of:

25 g. of the cellulose acetate Cellit L.l000 in 1000 ml. of acetone and drying.

On the dry intermediate layer a layer containing acidneutralizing organic material is applied by treating it with a liquid containing:

50 g. of decamethylene diamine 5 g. of non-colloidal silica 950 ml. of a solution of 70 g. of the polyvinyl alcohol Mowiol 5098 in 300 ml. of ethanol and 700 ml. of water and drying.

A sheet of the diazotype paper thus obtained is imagewise exposed and developed as in Example II. The copy shows a blue-green image on a white background.

Example XIII White base-paper of 70 g./m. for the diazotype process, which has been pre-coated with an aqueous dispersion of silica and dried, is sensitized with the sensitizing liquid described in Example XII and dried.

On the dry light-sensitive layer an intermediate layer of about 1 g./m. is applied by treatment with a solution of:

25 g. of the ethylcellulose Hercules 10 c.p.s. in 1000 ml. of acetone and drying. The material thus produced is then coated with a layer containing an acid-neutralizing material with the aid of a liquid containing:

40 g. of octamethylene diamine 4 g. of non-colloidal silica 950 ml. of a solution of 70 g. of the polyvinyl alcohol Mowiol 50-98 in 300 ml. of ethanol and 700 ml. of water.

A sheet of the diazotype paper thus obtained is imagewise exposed and developed as in Example I. The copy obtained shows a blue-green image on a white background.

Example XIV and dried. The dry light-sensitive layer contains about 4 g. of polymer per m.

The dry light-sensitive layer is provided with an intermediate layer and a top layer containing acid-neutralizing material, as described in Example III.

Upon imagewise exposure and development of a sheet of the diazotype paper thus produced as in Example II, a copy With a red azo-dyestufi image on a. white background is obtained.

The diazotype paper has reasonable keeping qualities.

(b) If instead of the above-mentioned sensitizing liquid a liquid containing:

12 g. of 4-p-tolylthio-2,S-diethoxybenzene diazonium chloride, zinc chloride double salt 24 g. of ethanolamide of fi-resorcylic acid 40 g. of citric acid 400 ml. of water 600 ml. of Vinnapas R60 is used, and if a heat-developable two-component diazotype paper is produced by an otherwise entirely identical method to that described above, such paper has reasonable keeping qualities, and after imagewise exposure and development yields copies with a red-brown azo-dyestuif image on a white background.

What we claim is:

1. A heat-developable diazotype material comprising a support carrying in cohering superposed relation on a side thereof (a) a light-sensitive two-component diazotype layer containing a light-sensitive diazo compound, an azo component capable of coupling with said compound to form an azo dyestulf and a substance preventing coupling of said component with said compound,

(b) a developer layer containing an agent capable of reacting with said substance to render it incapable of preventing said coupling, and

(c) between said layers a thermoplastic film layer holding said agent inaccessible to said substance at normal atmospheric temperatures, said agent being in liquid state upon a heating of said layers insufficient to pyrolyze said diazo compound, and said film layer upon such heating melting and admitting said agent in liquid state into said light-sensitive layer to bring about said coupling.

2. A diazotype material according to claim 1, said support being a paper support carrying said light-sensitive layer next to a surface thereof, said support and said light-sensitive layer being permeable by a gas capable of reacting with said substance, to render said substance incapable of preventing said' coupling, whereby after an imagewise exposure of the light-sensitive layer to actinic light an image of said dyestuff may be developed therein either by said heating or by contacting said support with said gas.

3. A diazotype material according to claim 1, said support being paper carrying next to and between its surface and said light-sensitive layer a coating inhibiting penetration of said diazo compound and said azo component into the paper.

4. A diazotype material according to claim 1, said light-sensitive layer containing, in addition to said diazo compound, said azo component and said substance, -finely divided solid particles rendering said light-sensitive layer quickly permeable by said agent in liquid state.

5. A diazotype material according to claim 4, said solid particles lbeing particles having an average size of about 0.1-3 microns, of a thermoplastic high-molecular polymer of an olefinically unsaturaated compound having a terminal methylene group, and being present in a quantity of 1-6 grams per square meter of said lightsensitive layer.

6. A diazotype material according to claim 1, said film layer being a continuous thin layer having a weight not exceeding 4 g./rn.. of a polymeric substance selected from the group consisting of hydrophobic polymers of olefinically unsaturated compounds having tenminal methylene group, hydrophobic cellulose esters and ethers, and mixtures thereof.

7. A diazotype material according to claim 5, said film layer being a continuous thin layer formed 'by coating and drying upon said light-sensitive layer a solution of a polymeric substance selected from the group consisting of hydrophobic polymers of olefinically unsaturated compounds having terminal methylene groups,

hydrophobic cellulose esters and ethers, and mixtures thereof, in a solvent that attaches said film layer to particles of the polymer in said light-sensitive layer.

8. A diazotype material according to claim 7, the polymer in said light-sensitive layer comprising a polyvinyl acetate and having a molecular weight of at least 500,000 and an average particle size of 0.8-3 microns, and said polymeric substance comprising a polyvinyl acetate and having a molecular weight greater than that of the polymer in said light-sensitive layer.

9. A diazotype material according to claim 1, said substance being an acidic compound and said agent being a normally solid organic material that melts at a temperature below C. and is capable in liquid state of neutralizing said acidic compound.

10. A diazotype material according to claim 1, said developer layer forming an outer surface of said material, being pervious to the light to which said diazo compound is sensitive, being dry and solid at room temperature, and comprising a mixture of said agent with a finely divided substantially inert solid rendering said outer surface amenable to being written upon.

11. A heat-developable two-component diazotype paper comprising a paper support carrying thereon a lightsensitive layer which contains a diazonium compound, an azo component capable of coupling with said compound to form an azo dyestufi and an acidic compound effective at room temperature to prevent coupling of said component with said diazonium compound, the said constit-uents being disposed in a liquid permeable layer structure constituted by 16 grams per square meter of said layer of a finely-divided thermoplastic high-molecular polymer of an olefinically unsaturated compound having a terminal methylene group; superimposed upon the said layer a continuous thin hydrophoibic thermoplastic film layer having a weight not exceeding 4 g./m. and substantially constituted by a polymeric substance selected from the group consisting of hydrophobic polymers of olefinically unsaturated compounds having tenminal methylene groups, hydrophobic cellulose esters and ethers, and mixtures thereof, said film layer being firmly fixed to particles of said polymer present in said light-sensitive layer; and superimposed upon said film layer a layer which is pervious to light to which said diazonium compound is sensitive, is dry and solid at room temperature, and comprises a mix ture of a finely-divided substantially inert solid and a normally solid acid-neutralizing organic material that melts at a temperature below 100 C. and is selected from the group consisting of non-volatile and'only slightly volatile amines and salts of such amines with weak acids; said film layer melting and admitting said acid-neutralizing material in molten state to said light-sensitive layer, so as to neutralize said acidic compound and thus bring about said coupling, upon a heating of said layers insufficient 'to pyrolyze substantially said diazonium com-- pound. 1

12. A heat-developable two-component diazotype paper comprising a paper support carrying thereon a lightsensitive layer which contains a diazonium compound, an azo component capable of coupling with said compound to form an azo dyestuif and an acidic com pound effective at room temperature to prevent coupling of said component with said diazonium compound, the said constituents being (disposed in a liquid permeable layer structure constituted by 1-6 grams per square meter of said layer of a finely-divided thermoplastic highrnolecul-ar polymer of an olefinically unsaturated compound having a terminal methylene group which polymer is attacked by a solvent for polyvinyl acetate; superimposed upon the said layer a continuous thin hydrophobic thermoplastic film layer having a Weight not exceeding 4 g./m. and substantially constituted by a polyvinyl acetate having a molecular weight of more than 500,000, oaid film layer being firmly fixed to particles of said polymer present in said light-sensitive layer; and superimposed upon said film layer a layer which is pervious to light to which said diazonium compound is sensitive, is dry and solid at room temperature, and comprises a mixture of a finely-divided substantially inert solid and a normally solid acid-neutralizing organic material that melts at a temperature below 100 C. and is selected from the group consisting of non-volatile and only slightly volatile amines and salts of such amines with weak acids; said film layer melting and admitting said acid-neutralizing material in molten state to said light-sensitive layer, so as to neutralize said acidic compound and thus bring about said coupling, upon a heating of said layers insutficient to pyrolyze substantially said diazonium compound.

13. A heat-developable two-component diazotype paper according to claim 11, said layer structure being a product of the drying of an acid aqueous dispelrison of a finely-divided polyvinyl acetate having a molecular weight of at least 500,000 and an average particle size of 0.8-3 microns; said film layer being a product of the drying of a solution of said polymeric substance in a solvent for polyvinyl acetate in which said diazonium compound, said azo component and said acidic compound do not appreciably dissolve.

14. A heat-developable two-component diazotype paper according to claim 11, said acid-neutralizing organic material being a water-soluble N-(alkylcarbonylamido) ethyl-N-ethanolamine the alkyl radical of which contains at least 6 carbon atoms.

15. A heat-developable two-component diazotype paper according to claim 11, said diazonium compound being a diazonium salt of a 4-morpholino-2,5-dialkoxy aniline.

16. A heat-developable diazotype material comprising a support carrying in cohering superposed relation on a side thereof (a) a light-sensitive two-component diazotype layer containing a light-sensitive diazo compound, an azo coupling component capable of coupling with said compound to form an azo dyestutf, an acidic compound preventing coupling of said component with said diazo compound, and finely divided solid particles rendering said layer quickly permeable by liquid,

0b) a developer layer over the outer side of said lightsensitive layer, said developer layer being pervious to the light to which said diazo compound is sensitive, being dry and solid at room temperature, and containing a N-(alkylcarbonylamido) ethyl-N-ethanolamine having an .alkyl radical of 6-18 carbon atoms, which amine melts at a temperature below C. and is capable in liquid state of neutralizing said acidic compound to render the latter incapable of preventing said coupling, and

(0) between said layers a thermoplastic film layer holding said amine inaccessible to said light-sensitive layer at normal atmospheric temperatures, said film layer being composed essentially of a polymeric substance selected from the group consisting of hydrophobic polymers of olefinically unsaturated compounds having terminal methylene groups, hydrophobic cellulose esters and ethers, and mixtures thereof,

said amine melting to liquid state, and said film layer melting and admitting said lQIHlIlE in liquid state into said light-sensitive layer to bring about said coupling, upon a heating of said layers insufficient to pyrolyze said diazo compound.

References Cited by the Examiner UNITED STATES PATENTS 3,046,128 7/ 19162 Klimlcowski 9675 X 3,140,180 7/1964 Fritz 9691 X 3,140,181 7/1964 Wilders et a1. 9649 X FOREIGN PATENTS 1,249,913 11/ 1960 France. 1,255,950 2/ 196 1 France.

815,005 6/ 1959 Great Britain.

OTHER REFERENCES Kosar, Photographic Science and Engineering, vol, 5, No. 4, July-Aug. 1961, pages 239-243.

NORMAN G. TORCHIN, Primary Examiner.

R. L. STONE, C. BOWERS, Assistant Examiners.

Claims

1. A HEAT-DEVELOPABLE DIAZOTYPE MATERIAL COMPRISING A SUPPORT CARRYING IN COHERING SUPERPOSED RELATION ON A SIDE THEREOF (A) A LIGHT:SENSITIVE TWO-COMPONENT DIAZOTYPE LAYER CONTAINING A LIGHT-SENSITIVE DIAZO COMPOUND, A AZO COMPONENT CAPABLE OF COUPLING WITH SAID COMPOUND TO FORM AN AZO DYESTUFF AND A SUBSTANCE PREVENTING COUPLING OF SAID COMPONENT WITH SAID COMPOUND, (B) A DEVELOPER LAYER CONTAINING AN AGENT CAPABLE OF REACTING WITH SAID SUBSTANCE TO RENDER IT INCAPABLE OF PREVENTING SAID COUPLING, AND (C) BETWEEN SAID LAYERS A THERMOPLASTIC FILM LAYER HOLDING SAID AGENT INACCESSIBLE TO SAID SUBSTANCE AT NORMAL ATMOSPHERIC TEMPERATURES, SAID AGENT BEING IN LIQUID STATE UPON A HEATING OF SAID AGENT BEING SUFFICIENT TO PYROLYZE SAID DIAZO COMPOUND, AND SAID FILM LAYER UPON SUCH HEATING MELTING AND ADMITTING SAID AGENT IN LIQUID STATE INTO SAID LIGH-SENSITIVE LAYER TO BRING ABOUT SAID COUPLING.