DE1081760B - Diazotype material and process for its preparation - Google Patents

Description

The invention relates to diazotype materials, which contain metal fluorides which are practically insoluble in water, which in finely divided form Surface of the support of the photosensitive layer separately from the sensitization or together with this cover.

The invention also relates to a process for the production of this type of diazotype materials.

Diazotype photosensitive materials containing metal fluorides usually consist of a carrier made of paper, cardboard, cellulose film, fabric and the like, which is covered by a photosensitive mixture of diazonium salts. When developing, this becomes Salt converted into dye by means of a coupling component, which is either the diazonium salt mixture or added to the developer.

One of the main characteristics of diazotype materials is the optical density of the image lines that hereinafter referred to as "density" and depends on the concentration of diazonium salt. The bigger this is the density, the more contrasting the image and the better the legibility of the copy.

The maximum density of a diazotype material is directly related to the exposure it receives to obtain a suitable copy. The following is called "sensitivity" of the material denotes the reciprocal value of the exposure that is necessary to obtain the white background of the copy. In general, as the maximum "density" of a diazotype material increases, its sensitivity decreases away.

The invention enables a larger one to be achieved "Density" of the image made from a diazotype material without reducing sensitivity. It also enables the use of more dilute sensitizing solutions for the same "Density" with a greater sensitivity than with the known sensitizing solutions that do not have any contain insoluble and finely divided metal fluorides.

If the area of maximum "density" of an exposed and developed copy is examined under the microscope at low magnification, it can be determined that the elementary areas of the surface fibers have a lower optical "density" than the elementary areas of the spaces between the fibers. This is due to the fact that the opacifying dye formed during development is largely located in the interior of the fiber in the case of surface fibers and therefore partially allows the specular reflection to exist. In the interstices, however, the dye formed completely covers the underlying fibers. When metal fluorides are used according to the invention, diazotype material
and its method of manufacture

Applicant:
SARL »S. A, P, HI «Societe Alsacienne

de Papiers Heliographiques Industrieis,
Paris

Representative: Dr.-Ing. E, Hoffmann, patent attorney,
Munich 22, Widenmayerstr. 34

Claimed priority:
France 6 December 1956

Raphael Landau, Epinay, Seine (France),
has been named as the inventor

notice that the specular reflection of the fibers decreases. This reduction can easily be determined when the angle of incidence at which the copy is illuminated is changed.

Incidentally, with a known type of diazotype material without metal fluorides, the maximum density is much less if a front lighting at an angle of 90 ° is used than for a side lighting Lighting. This difference is in the case of a diazotype material containing metal fluorides according to the invention greatly reduced. Because you always have a copy coming in one of several directions Examined diffuse light, it turns out that if the mentioned copy has a reduced specular reflection has a greater "density" than a copy with a very pronounced mirror reflection.

Furthermore, the finely divided state of the metal fluorides according to the invention enables better distribution of the dye formed when developing the diazotype material, so that an equal amount of a The absorbent material covering a given area absorbs the more when it is in finely divided form State.

009 50OT64

The finely divided pigments, such as zinc oxide, barium sulfate, Titanium white and the like, however, cannot be used in the context of the invention, since they form the support surface cover with a white layer that reduces their maximum density, rather than putting the dye on the To finally fix the surface of the support in a form in which the incident light is as strong as possible absorbed and thus the mirror reflection of the fibers is reduced.

In addition, when using the known precoats based on silicon or aluminum oxide or various synthetic resins reduce mirror reflection to a certain extent, however, these substances are not as effective and lead as the metal fluorides according to the invention to diazotype materials, which are not very homogeneous and more laborious as well as more complicated to produce.

The preceding explanations have only been given to facilitate understanding of the invention. In any case, it is certain that by using finely divided metal fluorides the real or apparent maximum density of the diazotype material is increased without reducing the sensitivity. The achievable "density" depends on the grain size of the metal fluoride. With a diameter of more than 1 to 2 microns, the increase in this "density" is relatively small, while at a diameter between 0.1 and 0.50 microns is particularly thick. If the grain size is less than With a diameter of 0.01 microns, the surface becomes less matt, but the absorption capacity remains increased still relatively high. When the diameter of the grains is greater than 0.5 microns the increase is less pronounced.

According to the invention, all can be practically insoluble Metal fluorides, especially those of the following metals: calcium, barium, strontium, magnesium, Aluminum or zinc, in a finely divided state, can be used.

These metal fluorides can be produced by having one dissolved in water or in suspension Metal compound, for example a chloride, a sulfate, a nitrate, a hydroxide and the like of calcium, of strontium, barium, magnesium, aluminum or zinc etc with a compound which contains a fluoride anion, for example with the fluorides of sodium, Potassium ^ ammonium, with gaseous or aqueous hydrofluoric acid, etc. Furthermore, one or several of these elements are implemented in gaseous form.

The preferred method is to use the metal fluoride precipitate in water, the reaction conditions taking into account the Temperature, time and concentration of the solutions are controlled so that a suspension is obtained in which the grain size is largely between the limits given above is from 0.01 to 0.50 microns. If necessary, the product obtained can be filtered, dialysis, Decant or purify by other suitable means. Furthermore, if necessary, a Colloid mill used for grinding caked grains ^

The metal fluorides are used either separately or mixed together, for example zinc and / or calcium fluoride, aluminum and / or calcium fluoride, zinc and aluminum fluoride, etc .; the best results can be achieved with calcium and / or zinc fluoride both when used separately as can also be achieved in a mixture. The metal fluorides can be in solid form, in powder form or with the aid of a Colloid mill dispersed in the sensitizing solution can be used. Furthermore, the metal fluorides in the form of a concentrated aqueous colloidal dispersion which is also concentrated Solution existing sensitizing solution can be added in such a way that the addition of the fluoride the reinstatement of the awareness solution

ίο enables the desired concentration.

The metal fluorides can be applied to the support of the photosensitive layer in one of the sensitization processes prior work step, which can be referred to as "pre-coating", can be applied.

The precoat solution then contains 1 to 25% metal fluoride, depending on the strength of the one desired Effect, the ease of using a concentrated solution and the economic Conditions. These three factors are best combined when creating solutions with between 3 and 10 weight percent fluorides can be used.

The precoating solution or the sensitizing solution may further contain fluorides other products, such as stabilizers (thiourea, 1,3,6-naphthalenetrisulfonic acid, citric acid, tartaric acid, Boric acid, phosphoric acid, etc.), part of the coupling component or components, diazonium salts, Wetting agents (saponin), colloids (gelatin, gum arabic, starch, etc.), development accelerators (Glycerin, glycol, etc.), dispersed resins (urea-formaldehyde, thiourea-formaldehyde, . Dicyandiamine-formaldehyde, polyvinyl acetate, etc.).

After this first layer has dried, the sensitizing solution is applied to the support in a known manner upset. In the sensitization mixture, the French patents 1 095 092, 1 096 363, 1 096 744 and 1 097 264 mentioned diazonium salts are used, namely the diazonium compounds, derived from

p-hydroxyethyl-ethyl-aminoaniline,
p-ethyl-aminoorthotoluidine,
p-diethyl-aminoaniline,
p-amino-diphenylamine,
p-benzylethyl-aminoaniline, etc.,

which can be used in their stabilized form, for example in the form of the double salts of Zinc chloride, tin chloride, chlorosulfobenzene, etc.

As coupling components, which with the di-

azonium salts form dyes during development and are used separately or in a mixture can, are to be mentioned: the R-salt, the Schaeffer salt, the 2,3-dihydroxynaphthalene-6-sulfonic acid, the Phloroglucinol, Resorcinol, Acetylacetanilid etc.

The metal fluorides can be in a finely divided state

also the cellulose pulp in the production of the carrier paper sheet, preferably with the approaches and incorporated in variable proportions, depending on the effect to be achieved. This share can be between 1% and the total amount of the normal approach (from kaolin, barium sulfate, titanium oxide etc.) fluctuate. A larger amount, between 20 and 90%, of the batch is preferably allowed to exist, whose job is to make the paper opaque.

It is known per se to add fluorides to diazotype layers, but only those which are significant To the extent that they are soluble in water. For example

Titanium potassium fluoride has been used, which is soluble in 13 g per liter of water at 20 ° C. The after The effect achieved by the invention cannot be achieved with fluorides that are so highly water-soluble.

The finely divided metal fluorides can be used at any stage in the manufacture of the paper between the Formation of the paper web and the final calendering either by surface treatment or incorporated by immersing the entire paper web in a colloidal metal fluoride suspension will.

The most common carrier used is paper, but other materials such as cardboard, Gelatin paper, art paper, cellulose film or cellulose esters stiffened on the surface, etc., are used will.

The use of metal fluorides under the conditions given above imparts the photosensitive ones Diazotype materials have the advantage of a »density« and a higher copy sensitivity are considered to be those of similar diazotype materials that either do not use Metal fluorides or with such, but in proportions thereof, are produced that are above or below the limits given above.

Finally, the use of metal fluorides enables the advantages indicated above in addition, an increase in the speed of development. In addition, a greater uniformity can be achieved achieve the coupling component mixture if, for example, blackening is to be achieved. In fact, with the help of these fluorides you can control the fluctuations in color depending on the person Conditions (low or high temperature) under which ammonia development occurs, be decreased ..

The invention is illustrated in more detail by the following examples. However, she is neither on these examples still limited to the details given in these. The quantities given are unless otherwise stated, parts by weight.

example 1

An aqueous dispersion of calcium fluoride is prepared in the following way: There are with equal volumes of a solution of 5 percent by weight anhydrous calcium chloride and a solution of 3.5% by weight of sodium fluoride (or also of 3% ammonium fluoride or 4.5% potassium fluoride) mixed.

A backing paper of the type customary in the diazotype process with a layer of this is then applied Dispersion coated in a coating machine for diazotype material.

After drying, the paper pretreated in this way becomes common with one of the following Coated sensitization mixtures used in the diazotype.

Sensitization Mix I (gives blue copies)

Glycerin 3 ecm

Tartaric acid 3 g

Thiourea 3 g

Zinc chloride 3 g

2,3-D ihy droxy naphthalene

6-sulfonic acid 2 g

p-diazo-dimethylaniline 2 g

Fill up with water up to 100 ecm.

Sensitization Mix II (gives black copies)

Ethylene glycol 3 ecm

Citric acid 5 g

Thiourea 3 g

Zinc chloride 3 g

2,3-dihydroxynaphthalene 0.5 g

2,3-dihydroxynaphthalene

6-sulfonic acid 0.8 g

Acetoacetanilide 0.7 g

Phloroglucine 0.1 g

p-Diazo- (N-hydroxyethyl-N-ethyl) -

aniline 2.8 g

Fill up with water to 100 ecm.

Example 2

The procedure is as in Example 1, with the exception that instead of calcium chloride an equimolecular Amount of zinc chloride or sulfate is used.

Example 3

The procedure is as in Example 1, with the difference that half of the calcium chloride through an equimolecular amount of zinc chloride or sulfate is replaced.

Example 4

The procedure is as in Example 1, with the change that an aqueous suspension of calcium fluoride the commercially available calcium fluoride is used when grinding with water in a colloid mill until a suspension is obtained, the particles of which for the most part have a diameter smaller than 1 micron.

B e i s ρ i e 1 5

A backing paper of the type used in the diazotype is made with a mixture of the example 1 given composition sensitized, however, 5 percent by weight zinc fluoride and / or calcium fluoride in the form of a fine powder, the grain size of which after dispersing in the sensitizer has been reduced to less than 1 micron in diameter using a colloid mill.

Example 6

A backing paper of the type used in the diazotype is made with a mixture of the example 1 given composition, with the exception that instead of 100 ecm of water only 75 ecm to be used to prepare the sensitization solution and this to 100 ecm with a The dispersion of zinc fluoride and / or calcium fluoride is made up with 20 percent by weight of metal fluoride, so that finally a concentration of 5% of metal fluoride is obtained.

Example 7

Examples 1 to 6 are repeated with the exception that a paper is used as the support which is covered with a pigment layer, for example art paper and baryta paper.

g examples

Metal fluorides, for example calcium fluoride and / or zinc fluoride and / or magnesium fluoride etc., the particles of which have the dimensions given above, are 10 to 50% by weight of the dry extract of one

Mixed baryta mixture, as it is used for the production of art print or baryta paper.

The paper pre-coated in this way is treated with a sensitizing mixture according to Example 1 coated.

Example 9

A backing paper of the methods known in the diazotype process for semi-wet under the name "development" process type used is pre-coated with a colloidal suspension of a mixture of 4 weight percent calcium fluoride, and l, 5 ^Q / aZinkfluorid.

After drying, the pre-coated surface is coated with the following mixture of diazonium salts sensitized, which is used in the so-called semi-wet development process.

p-Diazo- (N-benzyl-N-ethylamino) -

aniline 2 g

Tartaric acid 2 g

Gelatin 2 g

Thiourea 2 g

Fill up with water to 100 ecm.

The image is developed with a solution of the following composition:

Potassium carbonate 2 g

Sodium borate 2 g

Sodium thiosulphate 3 g

Phloroglucine 0.3 g

Fill up with water to 100 ecm.

Example 10

A paper suitable for the semi-wet development process is made with a bath of the following Composition sensitized:

Aqueous dispersion of 6% calcium fluoride, the grain size of which is smaller

than 1 micron, IQO is ecm

l-diazo-4-benzoylamine-

2,5-dimethoxybenzene ■ 2.5 g

Monosodium phosphate ... ,,, 2 g

1,3,6-naphthalenetrisulfonic acid 3 g

Thiourea 2 g

Concentrated hydrochloric acid 1 ecm

- The image is developed with a solution of the following composition;

Sodium formate,. ,,, .., ... ,, 8 g

Sodium benzoate .. ,, 3 g

Thiourea ,,,.,.,, 2 g

Phloroglucine, 0.4 g

Resorcinol, 0.2 g

Claims (6)

Patent claims: 1. Diazotype material composed of a photosensitive diazonium salt, a fluoride and optionally a product which serves as a coupling component for azo dyes, thereby characterized in that it contains at least one metal fluoride which is practically insoluble in water and which is present in fine grain form, preferably in a particle size of about 0.01 to 0.5 microns. 2. Material according to claim 1, characterized in that that it is the fluorides of calcium, barium, strontium, magnesium, or aluminum Contains zinc, each on its own or mixed with others. 3. Diazotype material according to claim 1 and 2, characterized in that the fluorides in a special layer on the support for the photosensitive layer or in the support substance are located. 4. diazotype material according to claim 1 or 2, characterized in that the fluorides in the photosensitive layer. 5. Method of making a diazotype material according to claims 1, 2 and 4, characterized in that a light-sensitive Diazonium salt-containing mixture is applied to a carrier, which beforehand at least an insoluble metal fluoride has been incorporated. 6. Method of making a diazotype material according to claims 1 to 3, characterized in that the for the production of the At least one insoluble metal fluoride is incorporated into the slurry used in the carrier. Considered publications:
German patent specification No. 922 390. © 0Oi 509/354 5.60