GB Patent 953908 - Improvements in and relating to two-component diazotype paper

Description

t -- --d

PATENT SPECIFICATION

NO DRAWINGS.

Date of Application and filing Complete Specification:

July 18, 1961.

No. 26062/61.

Application made in Netherlands (.Yo. 254,486) on Aug. 3, 1960.

Complete oSpecification Published: April 2, 1964.

Crown Copyright 1964.

Index at Acceptance:-G2 CD7.

International 0Classification:-G 03 c.

COMPLETE SPECIFICATION.

Improvements in and Relating to Two-Component Diazotype Paper.

EPMATA SPECIFICATION NO. 953,908

Page 2, lines 65 end 66 for "2-hydrozmethyl- 1', 2' 4, 5-naphthamidizolew read "ydroxyethyl -1', 2', 4, 5- naphthimldazole1, Page 4, llne 12 after "is" insert "precoated with approximately lOg/ri2"; Page 4, llne 114 for "Vinnapassn read "Vinnapas" Page 5 for line 17 read line 18 Page 5 for line 17 read "30g or zinc chloride" Page 5, line 18 for Y1Egn read "20g" Page 5, line 90 for "whic" read "white, Page 6, line 2 for "naphtllomldazale" read "naphthimlidazole" Page.6, lines 15 and 16 after "group" (second occurrence) delete "or a hydroxymethyl group" ITE PATENT OFFICE, 16th October, 1964 D 29452/1(1)/R. 109 200 10/64 TXL pllenyl) j-metnyt pyrazolone-[,). u pUll coupling, these combinations yield watersoluble azo dyestuffs.

In such diazotype papers use is also made of diazo compounds with one or more substituents enhancing the solubility in water, such as diazo compound with a dialkylamino group in para-position, in which one or both of the alkyl radicals carry a hydroxyl group, such as p-diazo N-ethyl N-hydroxyethylaniline, or a diazoa6cILL0 alv ------ ------. ^t� - _ nitrogen atom, such as: aryl derivatives of guanidine and biguanidine (Specifications Nos. 316,563 and 318,108), amines, such as cyclohexylamine, dicyclohexylamine, morpholine, amylamine, glycine, quinoline, and ethylene diamine (Specification No. 640,491), aliphatic polyamines, such as polyethylene imine and the reaction product of polyethylene diamine and dimethyl sulphate (German Patent Co mo 953,908 PATENT SPECIFICATION

NO DRAWINGS.

953,908 4,A,. Date of Application and filing Complete Specification:

> ff4v July 18, 1961. No. 26062/61.

Alpplication made in Netherlands (No. 254,486) on Aug. 3, 1960.

Complete Specification Published: April 2, 1964.

OtDOL () Crown Copyright 1964.

Index at Acceptance:-G2 0D7.

International Classification:-G 03 c.

COMPLETE SPECIFICATION.

Improvements in and Relating to Two-Component Diazotype Paper.

We, CHEMISCHE FABRIEK L. VAN DER GRINTEN N.V., a Limited Liability Company, organized and existing under the laws of the Kingdom of the Netherlands, residing at Venlo, the Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:-

The invention relates to two-component diazotype paper containing a light-sensitive diazo compound and an azo component, which upon development form together an azo dyestuff which carries at least one group enhancing the solubility of the azo dyestuff in water.

Such diazotype papers are known. For example, in such papers use may be made of combinations of a diazo compound derived from a p-phenylene diamine, and a readily water-soluble azo component of the naphthol type, such as 2,3-dihydroxy naphthalene 6-sulphonic acid, 2,7-dihydroxy naphthalene 3,6-disulphonic acid, 1,8-dihydroxy naphthalene 4-sulphonic acid, 2-hydroxy naphthalene 6-sulphonic acid, 2-hydroxy naphthalene 3,6-disulphonic acid, or of the phenol type, such as resorcinol sulphonic acids, phloroglucinol carboxylic acid, 1-acetylacetamino benzene 3-sulphonic acid, and 1-(4'-sulphophenyl) 3-methyl pyrazolone-(5). Upon coupling, these combinations yield watersoluble azo dyestuffs.

In such diazotype papers use is also made of diazo compounds with one or more substituents enhancing the solubility in water, such as diazo compound with a dialkylamino group in para-position, in which one or both of the alkyl radicals carry a hydroxyl group, such as p-diazo N-ethyl N-hydroxyethylaniline, or a diazonaphthol sulphonic acid, such as 2-diazo 1-naphthol 5-sulphonic acid and 1-diazo 2-naphthol 4-sulphonic acid. These diazo compounds yield water-soluble azo dyestuffs upon coupling with a polyvalent phenol, such as resorcinol and phloroglucinol, or a naphthol such as 2,3-dihydroxynaphthalene.

Two-component diazotype paper which contains a diazo compound and/or an azo component with a group enhancing the solubility in water, yields copies the azo dyestuff image of which has insufficient water-fastness, i.e. when the copies get wet, the azo dyestuff image will bleed owing to the solubility of the azo dyestuff in water. This is a serious drawback, which is especially inconvenient when the copies have to be painted with water colour, which is often the case in practice when copies are made from technical drawings. The azo dyestuff image then not only loses its sharp contours, but moreover the dissolving azo dyestuff will dirty the water colour.

Several agents have been suggested in the literature for improving the waterfastnes of the azo dyestuff image in copies made on two-component diazotype paper which contains a diazo compound and/or an azo component with a group enhancing the solubility in water. In the main these agents are substances containing a basic nitrogen atom, such as: aryl derivatives of guanidine and biguanidine (Specifications Nos. 316,563 and 318,108), amines, such as cyclohexylamine, dicyclohexylamine, morpholine, amylamine, glycine, quinoline, and ethylene diamine (Specification No. 640,491), aliphatic polyamines, such as polyethylene imine and the reaction product of polyethylene diamine and dimethyl sulphate (German Patent em c Specification No. 888,804), condensation products of (1) formaldehyde, (2) dicyanodiamide, and (3) a salt of ammonia or of an aromatic amine (Specification No.

660,088).

It has been proposed to improve the water-fastness of textile materials dyed with acid dyestuffs by the use of substances containing a basic nitrogen atom.

A suitable substance is, for example, a quaternary ammonium base obtained by peralkylation of 5,5'-methylene bis-(2methyl benzimidazole) (French Patent Specification No. 803,821).

The use of such a compound for improving the water-fastness of the azo dyestuff image in copies on two-component diazotype paper which contains an azo component with a group enhancing the solubility in water, has also been suggested in the literature (Fiat Report 813, microfilm P.B. 25 781, pages 85-86, Solidogen BS).

The above-mentioned substances indeed effect an improvement in the water-fastness of many azo dyestuffs. The said quaternary ammonium base and several of the condensation products of dicyanodiamide in general yield the best results, but the improvement effected with them still leaves a good deal to be desired. Thus, if relatively large quantities of these compounds are used, a reasonable improvement of the water-fastness can indeed be obtained, but large quantities have a detrimental effect on the development of the copies, so that weak images are often obtained. Moreover, both the said quaternary ammonium base and the said condensation products often form precipitates when added to aqueous sensitizing liquids which contain a diazo compound or an azo component with a group enhancing the solubility in water. In such cases these compounds have to be applied, in the production of the diazotype material, in a separate treatment before or after sensitization.

According to the present invention there is provided two component diazotype paper which carries a layer comprising (1) a lightsensitive diazo compound and (2) an azo coupling agent which is not a naphthimidazole derivative and couples more actively than 7'-hydroxy-1 ',2',4,5-naphthimidazole, the substances (1) and (2) coupling to form an azo dyestuff which contains at least one group which enhances its solubility in water, the azo coupling agent being present in a proportion sufficient to couple with all the diazo compound present, and (3) an agent for improving the water-fastness of the said azo dyestuff which is selected from 2-hydroxymethyl - 11,21,4,5 - naphthimidazole, 2-hydroxymethyl-1 l,21,4,5-naphthamidizole and 1l,2',4,5-naphthimidazoles having a hydrogen atom, a methyl group, a hydroxymethyl group or a hydroxyethyl group in 2-position and a hydroxy group 70 in 5', 6' or 71-position. Such diazotype paper yields copies the azo dyestuff image of which has excellent water-fastness, in many cases better than the azo dyestuff image of copies on corresponding 75 diazotype paper containing a comparable quantity of the best of the previously known agents.

The said imidazoles are all sufficiently soluble in the aqueous sensitizing liquids 80 commonly used for making two-component diazotype paper. Consequently they need not be applied in or on the diazotype paper in a separate treatment, before or after sensitization. In most cases they are 85 applied as salts of strong acids, such as hydrochloric acid.

In order to obtain copies with an azo dyestuff of excellent water-fastness in most cases a quantity of one or more of the 90 said imidazoles varying between 1 mol and 2 mols of imidazole per mol of diazo compound is applied in the diazotype paper according to the invention. Often smaller quantities will suffice, for example 95 when the imidazoles are applied in combination with one or more of the known agents for imparting water-fastness. If, however, the sole agent used for imparting water-fastness is a said imidazole, and 100 if the azo dyestuff contains more than one group enhancing its solubility in water, a quantity of imidazole which is larger than 2 mols per mol of diazo compound may be required. Such a larger quantity, 105 however, does not have a detrimental effect on the development of the copies, this being in contrast with, for instance, the effect of an equally active quantity of one of the condensation products of dicyanodiamide.

The required quantity of imidazole moreover is always considerably smaller than an equally active quantity of those condensation products. 115 Of course in diazotype papers containing diazo compounds and azo components, from which azo dyestuffs with poor waterfastness are formed, it is preferred that no agents which enhance the solubility 120 of the azo dyestuffs, such as polyethylene glycols, glycerol, and the like, should be present.

The agents for improving the waterfastness, applied in the diazotype paper 125 according to the present invention, are all very effective. Nevertheless there are differences in activity among them. The most active agents are the 11,2',4,5-naphthimidazoles the naphthalene nucleus of which 130 953,908 Diazotype material containing 61- or 71hydroxy 1',2',4,5-napthimidazole is known.

In Specification No. 523,922 6'-hydroxy

1U,2',4,5-naphthimidazole and 7'-hydroxy 11,2',4,5-napthimidazole have been suggested as azo components for the diazotype process. They couple slowly to form more or les red azo dyestuffs. In the diazotype material described in this Patent Specification no azo components other than 75 such napthimidazoles are employed.

Specification No. 596,048 describes twocomponent diazotype material which contains 71-hydroxy 11,2',4,5-napthimidazole in combination with a very small quantity 80 of a more actively coupling azo component.

The latter may be 1,8-dihydroxy naphthalene 4-sulphonic acid. Per gram molecule of diazo compound only 1/60-1/30 grammolecule of it is present. Consequently 85 the azo dyestuff formation in this diazotype material, at least in the poorly exposed and non-exposed portions, is not essentially determined by the 1,8-dihydroxynaphthalene 4-sulphonic acid, but 90 by the 71-hydroxy 11,2',4,5-napthimidazole.

The very small quantity of azo dyestuff formed from the 1,8-dihydroxynaphthalene 4-sulphonic acid moreover does not cause any serious lack of water-fastness of the 95 azo dyestuff image, not even in the portions where a large proportion of the diazo compound has been decomposed during exposure and only little azo dyestuff is formed from the 7-hydroxy 11,21,4,5naphthimidazole.

In modern two-component diazotype papers the highly light-sensitive diazo compounds derived from p-amino 2,5-dialkoxy phenyl morpholine, in which each 105 alkoxy group contains at most 2 carbon atoms, are often applied together with 2,3dihydroxynaphthalene 6-sulphonic acid or one of its water-soluble salts as the azo component and, if necessary, together with 110 other azo components, e.g. yellow-coupling ones. Because of their great lightsensitivity these diazo-type papers are very attractive. However, they yield copies the azo dyestuff images of which have 115 poor water-fastness and show an inconvenient red shade. If, however, these diazotype papers contain one or more of the above-mentioned imidazoles, they yield copies the azo dyestuff images of 120 which have excellent water-fastness and show a much more neutral colour.

For the preparation of 11,2',4,5-naphthimidazoles with a hydrogen atom, a methyl, a hydroxymethyl, or a hydroxyethyl group 125 in 2-position, the methods of preparation for the corresponding benzimidazoles described in Journal Chem. Soc. 1928, II, 2395, can be used, the starting product being naphthalen 1,2,diamine which carry in 5, 130 carries a hydroxyl group in 51, 61, or 71position, such as 51-hydroxy 11,21,4,5naphthimidazole, 51 - hydroxy 2 - methyl 1',2',4,5-naphthimidazole, 51-hydroxy 2hydiroxymethyl 11,21,4,5 - naphthimidazole, 5'-hydroxy 2-a-hydroxymethyl 11,21,4,5naphthimidazole, 51-hydroxy 2-fi-hydroxyethyl 1 1,21,4,5-naphthimidazole, 61-hydroxy 11,21,4,5 - napthimidazole, 61 - hydroxy 2methyl 1 1,21,4,5-naphthimidazole, 6'-hydroxy 2-hydroxymethyl 1 ',2',4,5-naphthimidazole, 6'-hydroxy 2-a-hydroxyethyl 1 1,2',4,5-napthimidazole, 6'-hydroxy 2-Phydroxyethyl 1 1,21,4,5-napthimidazole, 7'hydroxy 11,2',4,5-napthimidazole, 7'-hydroxy 2-methyl 11,21,4,5-napthimidazole, 71-hydroxy 2-hydroxymethyl 11,21,4,5napthimidazole, 71-hydroxy 2-a-hydroxyethyl 11,21,4,5-napthimidazole, 71-hydroxy 2-fp-hydroxyethyl 1 1,21,4,5-napthimidazole.

The possibility for writing with ink on copies in which these compounds are present is also greatly improved. This is especially important when a layer of fine particles of, for instance, silicon dioxide, alumrinium oxide, and the like is present on the surface of the copies. In order to increase the density of the azo dyestuff image and to improve the uniformity of the light-sensitive layer, modern diazotype papers are often provided with such fine particles either by applying liquid dispersions of the particles on the paper surface before sensitization or by adding them to the sensitizing liquid and then applying them on the paper surface together with the other components of the sensitizing liquid. These particles often cause serious ink-feathering in writing or drawing with ink on the copies the surface of which has been provided with such particles. If, however, one of the above-mentioned naphthimidazoles is also present on the surface of those copies, the said particles have a much smaller detrimental effect, if any, on the possibility of writing with ink on the copies, while their favourable influence on the density of the azo dyestuff image and the uniformity of the light-sensitive layer is maintained. The said napthimidazoles moreover will sometimes favourably affect the adhesion of such particles with colloidal dimensions to the surface of the copies.

The hydroxynaphthimidazole compounds are able to couple with diazo compounds to form azo dyestuffs, mostly red-coloured ones. Their coupling activity, however, is small. In the diazotype paper according to the invention an azo component is employed which is sufficiently active and is used in a quantity which is large enough to convert all the diazo molecules into azo dyestuff, so that no azo dyestuff is formed from the added hydroxynaphthimidazole.

953,908 6, or 7-position in sulphonic acid group which is converted into a hydroxyl group after closure of the imidazole ring (see BIOS Final Report 772, Item no. 22, page 5).

The following examples will serve to illustrate the invention. The words "Aerosil", "Vinnapas" and "Tylose" used in these examples are Registered Trade Marks.

EXAMPLE I.

White base-paper for the diazotype process of weight 80 g/m2 is of a dispersion of:g of "Aerosil (colloidal silica manufactured by Degussa, Frankfurt a/M, Germany) in 1000 cm' of water and dried.

The surface thus treated is sensitized (at room temperature) with a solution of:

16 g of p-diethylamino benzene diazonium chloride, zinc chloride double salt g of 2,3-dihydroxy naphthalene 6sulphonic acid sodium salt 14 g of tartaric acid g of citric acid g of thiourea g of naphthalene 1,3,6 - trisulphonic acid sodium salt g of zinc sulphate 7 aq.

g of zinc chloride g of N.N'-dimethylurea ml of "Vinnapas" H.60 (polyvinyl acetate emulsion manufactured by Wacker-Chemie G.m.b.H., Munich, Germany g of 71-hydroxy 11,21,4,5-naphthimidazole HCl-salt in100l cm0 of water and dried.

The light-sensitive side of a sheet of the diazotype paper thus obtained is covered with a tracing with broad ink-lines having good absorption for ultraviolet light (e.g.

black lines) and then exposed via the tracing until, underneath the blank portions of the tracing, the diazo compound has bleached out completely. After this the image is developed in ammonia vapour.

The diazotype copy thus made shows a dense blue image on a clear white background. The silica particles adhere well to the surface of the copy. It is possible to write or draw on the surface of the copy with various inks without encountering difficulties in the way of ink-feathering.

When this copy gets wet, it appears that the azo dyestuff image shows hardly any bleeding. The azo dyestuff image of a copy on diazotype paper sensitized with a liquid according to the above formula, but from which the imidazole has been omitted, on the contrary will bleed considerably under identical circumstances. The surface of such a copy will soon be damaged because the silica particles and the azo dyestuff present thereon tend to come off.

Several inks show serious feathering on such a copy.

If instead of 20 g of 71-hydroxy 1P,21,4,5naphthimidazole, 40 g of a quaternary ammonium base obtained by peralkylation of 5,51-methylene bis-(2-methyl benzimidazole) is used, an azo dyestuff image is obtained which still bleeds preceptibly when the copy gets wet. The sensitizing liquid is turbid. It is not possible to dissolve more than 40 g of this compound in the sensitizing liquid at room temperature.

If instead of the above-mentioned naphthimidazole it is desired to use one of the said condensation products of dicyanodiamide, these products, when added to the abovementioned sensitizing liquid, appear to form precipitates therein. They can indeed be added to the silica dispersion.

If 40 g of such a condensation product is added to the latter, a considerable improvement of the water-fastness of the azodyestuff image is obtained, but this image is much less dense than that according to the example.

EXAMPLE II.

White base-paper for the diazotype process of weight 80 g/m is sensitized with a solution of the following, applied at 18 C.:

17 g of 4-morpholino 2,5-diethoxy benzene diazonium chloride, zinc chloride double salt 100 g of 2,3-dihydroxy naphthalene 6sulphonic acid sodium salt g of 2,7-dihydroxy naphthalene 3,6-disulphonic acid sodium salt 1.3 g of acetylacetanilide 105 g of tartaric acid 3 g of boric acid g of zinc chloride g of N-2-hydroxyethyl N1-allyl thiourea 110 g of N.N'-dimethylurea g of 2-hydroxymethyl 11,21,4,5naphthimidazole HCl-salt cm3 of "Vinnapass" H.60 in 1000 cm' of water and dried.

A sheet of the highly light-sensitive diazotype paper thus prepared is imagewise exposed and developed as described in Example I. The copy obtained shows a 120 dense neutral black azo dyestuff image on a white background, which shows hardly any bleeding when the copy gets wet, this being in striking contrast with the azo 953,908 g of p-N-21-hydroxyethyl N-ethylamino benzene diazonium chloride, zinc chloride double salt g of tartaric acid g of boric acid g of thiourea g of zinc chloride g of resorcinol g of 2-methyl 71-hydroxy 11,2',4,5naphthimidazole 250 cm' of ethanol in 750 cm3 of water and then dried.

After imagewise exposure and development (as described in Example I) of a sheet of the diazotype paper thus obtained, a transparent diazotype copy with a brown image is obtained, which does not bleed when it gets wet.

The azo dyestuff image of a copy on corresponding diazotype material, but without imidazole, on the contrary has poor water-fastness.

The transparent copies obtained according to this example are very suitable as intermediate originals for making further copies on photoprinting material.

EXAMPLE VI.

Whie base-paper for the diazotype process of weight 80 g/m2 is treated on the side to be sensitized with a solution containing the following, applied at 18 C.:dyestuff image of a copy on corresponding diazotype paper which does not contain the imidazole.

EXAMPLE III.

White base-paper for the diazotype process of weight 80 g/m2 is sensitized with a solution of the following, applied at 18 C.:

14 g of 2-diazo 1Phydroxynaphthalene 5-sulphonic acid sodium salt 4 g of phloroglucinol g of tartaric acid g of urea 21 g of thiourea 13.5 gof sodium chloride 22.5 g of zinc sulphate 7 aq.

g of 71-hydroxy 11,2',4,5-naphthimidazole HCl-salt in1000 cm3 of water and dried.

A sheet of the diazotype paper thus made is imagewise exposed and developed as described in Example I. The copy obtained, which shows a violet image on a white background, has considerably better water-fastness than a copy on corresponding diazotype paper without the said imidazole.

EXAMPLE IV.

White base-paper for the diazotype process of weight 80 g/m2 is sensitized with a solution of the following, applied at room temperature: 17 g of p-dimethylamino benzene diazonium chloride, zinc chloride double salt gof 2 - hydroxynaphthalene 6sulphonic acid sodium salt g of citric acid 30 g of thiourea g of zinc chloride g of N.N'-dimethylurea g of 61-hydroxy 11,2',4,5-naphthimidazole HCl-salt 30 cm3 of "Vinnapas" H.60 in 1000 cm3 of water and dried.

A sheet of this diazotype paper is imagewise exposed and developed as described in Example I.

The copy shows a dense brown azo dyestuff image which exhibits hardly any bleeding when it gets wet. The copy can be properly painted with water colour. In diazotype paper not containing imidazole, the azo dyestuff of the image mixes with the water colour.

EXAMPLE V.

Tracing paper is sensitized with a solution of the following, applied at 20 C.:g cm' of 2-hydroxymethyl 11,21,4,5naphthimidazole HCl-salt and 95 of a 2% solution by weight of "Tylose" SL 100 (manufactured by Kalle Aktiengesellschaft, Wiesbaden - Biebrich, Germany) in water, 100 1000 cm' of water, and dried.

The paper thus precoated is sensitized with the sensitizing solution of Example I, from which the 71-hydroxy 1',21,4,5naphthimidazole HCl-sai,, however, has been omitted. A sheet of the diazotype paper is then imagewise exposed and developed in ammonia vapour. The azo dyestuff image of the diazotype copy is a 110 neutral blue and has excellent waterfastness.

The azo dyestuff image of a copy on corresponding diazo-type material, but without the imidazole, bleeds considerably 115 when it gets wet.