DE2220597C3 - Thermophotographic recording material - Google Patents

Description

15th

20th

is present in the

R is an alkyl, aryl, aroyl, arylsulfonyl or

heterocyclic group or the moiety

_x_ _NH -co-N / ^co \ A

25th

in which

X stands for an alkylene or arylene group,

means

2. Recording material according to claim 1, characterized in that R is an aryl group Denotes a phenyl or napthyl group and a benzoyl group as the aroyl group.

3. Recording material according to claim 1 and 2, characterized in that it contains the phthalazinone compound in a molar ratio of 1 to 4, based on the light-insensitive silver salt.

4. Recording material according to claim 1 to 3, characterized in that it is silver behenate or silver stearate as the light-insensitive silver salt contains

5. Recording material according to claim 1 to 4, characterized in that it is the photosensitive silver halide in amounts of 0.05 to 0.2 % By weight, based on the weight of the light-insensitive silver salt.

50

The invention relates to a thermophotographic recording material which is non-photosensitive Silver salt, a silver salt reducing agent and a toner composed of a phthalazinone compound, and light-sensitive silver halide and / or contains a polymethine spectral sensitizing dye.

In the recording process described in DE-PS 13 00 014, recording materials are used which contain an oxidizing agent Contain reducing agents and a minor amount of a photosensitive compound. To the exposed areas and with subsequent heating, a colored image is formed by a redox reaction. Organic silver salts are used as oxidizing agents and aminophenols and hydro are used as reducing agents xylamines, pyrrolidones or phenols furthermore, phenylenediamine or etherified naphthols, e.g. 4-methoxynaphthol-t, used. Heavy metal salts are suitable as light-sensitive compounds Exposure to form traces of free metal; in particular, they are photosensitive Silver salts, e.g. silver halides, which photolytically form silver on exposure. By this photolytically The redox reaction is initiated

Essential for the practical use of such Materials is the use of light-insensitive silver salts as oxidizing agents, such as. B. silver saccharide, or silver salts of long-chain fatty acids. Particularly high photosensitivity is achieved when the required silver halide is present on the surface of the light-insensitive silver salt by reaction with halide ions or a halide ion-forming Connection, e.g. B. according to the method described in DE-OS 15 72 203 is generated. These recording materials have a sensitivity im short-wave part of the spectrum according to the inherent sensitivity of the silver halides used and can also be sensitized for longer-wave light by adding spectral sensitizing dyes.

It is also a method of making photographic records on dry Ways are known in which a photographic recording material which contains a silver salt and a reducing agent for this silver salt is exposed imagewise and the exposed recording material is heated to a temperature at which the Reducing agent the silver compound in the exposed areas with the formation of a visible silver image reduced For this process, a photographic recording material is used with a layer which under the conditions of the process im essential light-insensitive silver compound, a reducing agent and a polymethine sensitizer for contains the spectral sensitization of the non-photosensitive silver compound

With these procedures - if appropriate measures are not taken - only yellow to Light brown silver pictures of poor contrast have been preserved. Better contrast can be achieved by increasing the Reducing agent can be achieved in the materials used. The measure has the following Disadvantages: The amount of reducing agent present in the photosensitive recording material must be kept to a minimum in order to avoid undesirable darkening of the casting solution or the Layer, d. H. to avoid a reduction in the organic silver salts during the production and storage of the recording material. Therefore this will be Recording materials preferably have weak reducing agents of the o-alkyl-substituted phenol type added, as described, for example, in DE-OS 19 08 761.

It is known to obtain images with sufficient optical density that have sufficient contrast in result of the finished recording to add so-called toners to the photosensitive layers, which the Shift image tone from brown to black. Such a compound is, for example, 2H-phthalazinone- (1). This toner, in combination with some silver salts and reducing agents, causes darkening the casting solution or the materials, whereby its

Usefulness is limited.

The invention is based on the object of developing toner for the above-described Phoiograpbischen Recording Roaterislien that the image tone of the Shift the silver image to black without increasing the stability of the recording material during production or storage by darkening worsen.

According to the invention, the object is achieved in that the phthalazinone compound is one of the following general formula

- CO-NHR

CH ^ ^N

is present in the

R is an alkyl, aryl, aroyl, arylsulfonyl

heterocyclic group or the moiety

in which

X stands for an alkylene or arylene group, means Suitable are e.g. B. the following connections:

(D

- CO - NH - CO - <T ^

/ V ^C ° N _N -CO-

NH

rn MU _ ^^ χ

- CO -NH- (CH ₂ J ₁₇ -CH ₃

(5)

^ N-CO-NH-C ₂ H ₅

It is also possible to use ζ, B, compounds of the above general formula, the 2 phthalazinone nuclei in the 2-StelJungen are connected by a -CO-NH-X-NH-CO group, where X is a divalent alkylene or arylene group means the phthalazinone derivatives of the above general formula are according to known methods, e.g., by reaction of phthalazione with an isocyanate, made The Preparation of compounds 1 and 2 is described below. Other of those in the invention Phthalazinones which can be used wisely are obtained in an analogous way.

Connection 1

A mixture of 146 g (1 mol) phthalazinone and 138 g (1.1 mol) phenyl isocyanate in 21% dry benzene is boiled for 4 hours with stirring. Then the solution is cooled and the precipitate formed suction filtered. This precipitate is washed with dry diethyl ether or diethyl ether.

Yield: 93%. Melting point: 154-156 ° C (decomposition).

Connection 2

To 146 g (1 mol) of phthalazinone, dissolved in 2 liters of boiling dry toluene, 147 g are added within 15 minutes (1 mol) benzoyl isocyanate added. The reaction product precipitates in the boiling solution. This The reaction mixture is stirred for 1 hour on the Maintained boiling point. Then it is cooled down the precipitate formed is filtered off with suction and washed with toluene.

Yield: 85%. Melting point: 179 ° C. The invention, a phthalazinone compound recording materials containing dung used for the methods described above for making recordings by dry means

By adding the phthalazinone compounds, the image tone of the silver images is as desired Shifted from yellowish-brownish to black to blue-black. The stability of the casting solutions for the layers and the stability of the layers themselves are not adversely affected by the addition of these toners. No browning occurs. About that In addition, surprisingly, the photographic properties, such as developability, in the (3) Comparison with the toner-free recording materials,

stabilized, especially under unfavorable conditions such as higher temperature and humidity, d. H.

under tropical conditions.

The first method uses a recording material having a layer which is a light-insensitive silver salt and generally thin Amounts of a photosensitive silver halide, as well as a reducing agent for reducing the silver salts at the exposed areas.

In the second method, a recording material is used with a layer containing a light-insensitive silver salt, a silver salt reducing agent te) and a generally small amount of a polymethine dye for spectral sensitization of the light-insensitive silver salt. This process is described in DE-OS 21 40 462. The sensitizing dyes are generally nen dissolved in organic solvents Casting solutions described below were added. The addition can also be in solid form to the silver salt before Grinding or just before the application of the

(6)

Casting solution is carried out on a carrier. The concentration of the sensitizing dye in the layer can vary within wide limits, it depends on the desired effect and the type of Sensitizing dyes in combination with the Silver salt, in general concentrations of 0.1-2 g of sensitizing dye, preferably 0.2-0.6 g per mole of silver salt has been found to be sufficient. In individual cases, the sensitizing dyes can also be added in amounts outside this range will.

The toners to be used in the manner of the present invention are preferably the photosensitive ones Layer added They can, however, also be partially added to an adjacent layer.

The toners to be used in the manner according to the invention can have various layers in the layers Quantities are added. The optimal amount depends on the desired effect and the layer composition. The optimal amount can go through few, simple experiments familiar to the average person skilled in the art can be found. Generally have Additions of 0.5-6 moles, preferably 1-4 moles, of the phthalazinone compound per mole of the non-sensitive silver salt, preferably an organic one Silver salt, proven to be sufficient.

The phthalazinone compounds to be used in the manner according to the invention can also be used in a mixture with known toners. the The concentration of the additional toners is preferably lower than that of the phthalazinone compounds. Reference is made to the unsubstituted phthalaz: - non, phthalimide or phthalimide derivatives, e.g. B. the compounds described in DE-OS 21 40 462.

The toners to be used in the manner according to the invention can be used in combination with those for the respective recording processes or materials and compounds known for the photosensitive recording material, e.g. B. reducing agents, Binding agents, silver salts and other heavy metal salts, white pigments and stabilizers are used will. Such materials are known and e.g. B. described in the following publications: DE-OS 13 00 014, 15 47 878, 15 72 203, 19 08 258, 19 08 761 and 20 31 748.

Organic reducing agents known for these processes contain active substances bonded to O, N or C Hydrogen atoms and are e.g. B. o-alkyl-substituted Phenols, di- and trihydroxyaryl-, aminophenols Aminonaphthol, p-phenylenediamine and hydroxylamine derivatives, alkoxynaphthols, acetoacetonitriles, PyrazoIidin-3-οπ- and pyrazolin-5 * one, indanedione-13, Ascorbic acid and hydroxychroman or hydroxycoumaran derivatives, e.g. according to DE-OS 20 31 748; 3. B. o-alkyl-substituted phenols, hydroquinone, aminophenol and methoxynaphthol derivatives are preferred.

Also in the case of the variant of the recording material according to the invention, in the case of the light-sensitive one If the compound silver halide is present, the layers can be modified by adding polymethine dyes be spectrally sensitized. As the sensitizing dyes, the compounds are preferably those which also usually for spectral sensitization conventional silver halide emulsion layers be used, d. H. Cyanine dyes, merocyanines, oxonols or rhodacyanines of various kinds, how they z. B. in the book by F. M. Hamen "The Cyanin Dyes and Related Compounds ", (1964).

To produce the recording material according to the invention, the components for the Redox reaction and the photosensitive silver halide together with a suitable binder The usual natural or synthetic film-forming polymers are suitable as binders, eg. B. proteins, especially gelatin, cellulose derivatives, especially cellulose ethers, cellulose esters or Carboxymethyl cellulose, alginic acid and derivatives thereof, starch ether or galactomannan; preferred as Binders are organic polymers such as copolymers of vinyl chloride and vinyl acetate or of Butadiene and styrene, polyethylene, polyamides, polyisobutylene, polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate or wholly or partially saponified polyvinyl acetate, Polyvinylidene chloride, polyvinyl pyrrolidone, polystyrene, chlorinated rubber, polyvinyl butyral, polymers of acrylic acid or methacrylic acid esters, acrylamide

jer copolymers of derivatives of acrylic acid and Methacrylic acid, cellulose derivatives such as nitrocellulose, cellulose acetates, cellulose propionates or mixtures such as cellulose acetobutyrate.

The recording layer can be applied as self-supporting splints, preferably however, it is applied to a suitable substrate, the substrate must be stable at the processing temperature between 60 and 200 ⁰ C. Suitable carriers are e.g. B. sheets or foils made of paper, cellulose acetates, polyethylene terephthalate, textile fabrics, metal foils or glass. In the case of paper backings, the papers can contain the usual auxiliary layers, such as barite layers and polyethylene layers.

As light-insensitive silver salts, e.g. B. in GB-PS Π 11 492 described silver salts of aliphatic carboxylic acids with a thioether group or silver salts of long-chain fatty acids such as silver behenate, silver palmitate or silver stearate.

The photosensitive silver halide is relatively small amounts of 0.05-0.2% by weight, based on the weight of the oxidizing agent light-insensitive silver salt, used. This proportion of photosensitive salt is sufficient for most Systems off. In exceptional cases, this percentage can be exceeded or not reached. The photosensitive silver halide should therefore be so small Amounts be present so that although photolytically formed silver metal nuclei can initiate the redox reaction that through the metal nuclei formed no or only negligible discoloration of the recording material takes place

Some of the inherently light-insensitive silver salts useful in the context of the present invention show upon precipitation in the presence of a protective colloid, e.g. B. proteins, especially gelatin, as usual in the production of conventional silver halide gelatin emulsions, a certain - if also low - photosensitivity In the precipitation of the silver salts for the production of the invention = When recording material, the procedure must therefore be such that the silver salts formed remain insensitive to light. This will generally be fine achieved when it is precipitated in the absence of a protective colloid.

The dried silver salts are then added to the solutions or dispersions of the desired layer

binder added.

The concentration of the silver salt in the binder dispersions can vary within wide limits, depending on the desired silver salt application in the recording layers. In general, amounts of 0.1-0.01 mol of silver salt per kilogram of casting solution are sufficient. 0.02-0.04 mol of silver salt is preferably used per kilogram of solution or dispersion. The same applies to the silver salt application in the finished recording material . Again, in the concentration can be varied depending on the desired effect, or the use within a wide range in general, the order is 0.1 ^-.!. 1 g silver in the form of the silver salt per m, preferably 0.3-0.6 g per m ² are Selbstver. - '> Of course, mixtures of different silver salts sensitive to lit!

will.

To improve the photographic characteristics of the recording material according to the invention, other light-insensitive heavy metal compounds can be added to the material, preferably to the layer containing the silver salt which is insensitive to radiation. This allows z. B. a Verminde: '<tion of the veil, an increase in the density or a shift in the image tone to desired shades, ζ. B. after neutral black, achieve.

Suitable for this are e.g. B. salts or compounds of mercury. Cadmium. Lead. Uranium. Gold. Platinum, palladium, or rhodium. The heavy metal compounds can be added during the precipitation of the silver salt. In this case, solutions of the heavy metal salts and the silver salts are preferably added to the submitted precipitation component in the double-jet process and are precipitated at the same time. Even if the joint precipitation of the silver salt and the heavy metal salt is particularly advantageous and, depending on the nature of the heavy metal salt, produces particularly favorable effects, the heavy metal salts can, however, also be added in solid or in dissolved form to the casting solutions already containing silver salt for the recording layer. The heavy metal salts may also be mixed with the dried silver salts by grinding or i ~ be added just prior to casting the casting solution for the recording layer. Combinations of different heavy metal salts can of course also be used.

The amount of heavy metal salts added can be greater than or equal to fluctuate within wide limits. Here, too, the concentration depends on the type of heavy metal salt and the silver salt and the desired effect The optimal amount can be achieved by a few simple Manual tests can easily be determined by any average person skilled in the art. The effectiveness of heavy metal salts is often more pronounced with joint precipitation. Suffice it here to achieve the desired effect mostly concentrations of 0.001 to 10 mol%. preferably 0.01-5 mol%. If you put the heavy metal salts at a later stage of the production of the recording material, approximately immediately before Shedding, concentrations of 0.001-02 are sufficient. preferably 0.005-0.07 moles of heavy flakes, e.g. B.Qüecksi! Beriii) -äceiäi. per MöI silver salt.

The recording materials can also contain white pigments, such as zinc oxide, silicon dioxide or titanium dioxide as fillers, for improving the whiteness and for Influencing the suitability of the layers to bond and improving the storage stability of terpene resins and contain organic acids. Such recording layers are in US Pat. No. 3,074,809 and 31 07 174 described.

For exposure of the recording materials according to the invention, those used in reproduction technology conventional light sources such as halogen lamps, iodine quartz lamps or incandescent lamps can be used. Which light source is used depends on the spectral sensitivity of the heavy metal salt used or sensitizer dye. The exposure time is a few seconds.

The development of silbersaizhaltigen up / calibration voltage materials happens in the heat at temperatures / wipe 80 and 200 ^r C. The heating can be done by, for. B. leads the recording material with srinrr Srhirhlseite over hot plates or rollers, or by irradiation with UR light. The recording material containing silver salt can be used in contact with a film, e.g. B. polyester film, are developed in the heat. The most favorable temperature and heating time naturally depend on the composition of the recording material. They can be determined by a few simple experiments.

example 1
Recording material

A mixture of the following composition is ground for several hours:

1.8 g silver behenate behenic acid (molar ratio I: 1).

one toner in the amount shown in the table below.

50 mg mercury (II) acetate.

1.5 g cellulose acetobutyrate,

0.75 g copolymer of vinyl chloride and vinyl acetate (uewicntsvernaitnis J: i),

26 g of methyl ethyl ketone.

0.5 mg of the sensitizer 5 - [(3-ethylthiazoli-

din-2-ylidene) ethylidene] -3-allyl-2-thio-oxazolidine-2,4-dione. solved in 0.5 m! Methyl ethyl ketone, and 1 g

Bis- (2-hydroxy-3-tert-butyl-5-methylphenyl) methane
added.

The casting solution is applied to a paper support and dried. The amount of silver applied is 3–0.6 g of silver in the form of the silver compound per m ² .

processing

The recording material is through a transparent template with tungsten lamps depending on their Intensity and the desired gradation exposed for 3-30 seconds and developed by heating Depending on the height of the temperature from 60-160 ° C and the device used, the development time is 3-80 seconds. As a developing device can be heated presses, drying drums, rollers or those in BE-PS 6 28174 or FR-PS 14 19 101, 14 16 752 and 15 12 332 described devices as well as commercially available devices are used will.

While only yellow image silver of low density is obtained without toner, in the presence the following toners can obtain black images of good density.

To protect the recording material and to The layer side of the material in contact with a can create a high gloss image Po'i'ester film can be developed in the heat.

In order to compare the stability of the recording materials according to the invention with those which contain known toners, namely the unsubstituted phthalazinone, test strips of the material containing the toner to be tested were tested in the following manner:

The unexposed strips became 20 with increasing temperature with gradient intervals of 5 ° C Developed for seconds. It was then determined the temperature at which the unexposed material a Shows development to a haze of 0.15-0.20. ] The higher this temperature is, the more stable it is photosensitive layer. The results of these investigations are summarized in the following table.

Tabel

g per toner Image tone Veil approach keen development temperature i.y 1 black 110 C 1.9 2 black 100 C 2.2 3 black 110 C 2 4th black 105 C 2.5 5 black 105 C 1 Comparison black 85 C attempt

The photosensitive toners according to the invention .in Compared to the phthalazinone-containing material, the recording material containing it has a

-1.1

temperature, therefore a better stability and also has a greater processing latitude. 0.1-0.2 g of phthalazinone can be added to the recording layers without any adverse effect on the stability Acceleration of development can be added.

Example 2

The following layers are applied to a base made of barytaised paper:

50 lyl-5- {2- [3-ethyl-benzoxazolylidene- (2)] ethylidene-2- thiohydantoin in chloroform,

0.15 g silicon dioxide,

55.0 g acetone,

1.0 g of a copolymer of vinyl chloride and

Vinyl acetate (weight ratio 22: 3) dissolved in

20 g butyl acetate,

3 g of compound 1, 0.2 g phthalazinone.

2. Top layer from the following casting solution: 10.0 g polyvinyl butyral,

4 g hydroquinone. 100 ml of methanol. 1.5 g toner 1.

The casting solution for the photosensitive layer is ground in a ball mill for 16 hours before application. The light-sensitive layer contains ^{0.7-0.9% silver per m 2} in the form of the specified silver salts.

The top layer is applied to the dried photosensitive layer. The concentration of the reducing agent in the top layer is 0.5-1.5 g per m ² .

The exposed recording material is developed in the heat as described in Example 1 and you get a black picture.

Example 3 Recording material

An equimolar mixture of silver behenate and behenic acid is made by precipitating silver nitrate with a solution of sodium behenate and behenic acid in alcohol and water. The precipitation will carefully washed and dried.

The suspension for the production of the layer is made by treating the following for 12 hours specified mixture produced in a ball mill:

240 ml of methanol,

125 ml of an IO% solution of polyvinyl butyral 111 rviciiiaiiui,

20 ml of a 10% solution of poly-N-vinylpyrrolidone in methanol,

30 g of the equimolar mixture of silver behenate and behenic acid,

10 ml of a 1% methanolic solution of ammonium bromide. 13 g toner 3, 15 g of 1-phenyl-3-methylpyrazolone- (5).

1. Photosensitive layer made from the following casting solution:

13 g silver behenate / behenic acid (molar ratio net 1: 1),

3.0 g cellulose acetate.

4.5 ml of a 1% calcium bromide solution in Methanol, 5.7 ml of a 1% methanolic solution of Mercury (II) acetate solution made by adding has been acidified by glacial acetic acid, 3.0 ml of a 0.01% solution of l-methyl-3-al- The above mixture is applied to a conventional paper backing in a concentration of 100 g per m ² and dried at room temperature.

processing

The recording material is exposed through a transparent original. A 750 is used as the light source Watt UV lamp used at a distance of 5 cm. The exposure time is 2 seconds. Then will Heated to a temperature of 120 ° C for seconds A black negative image of the original is obtained.

Claims (1)

Claims; 1. A thermal photographic recording material containing a light-insensitive silver salt Contains silver salt reducing agent and a toner composed of a phthalazinone compound and light-sensitive silver halide and / or a spectral sensitizing polymethine dye, characterized in that as Phthalazinone compound is one represented by the following general formula