DE2212302A1 - Thermophotographic recording material - Google Patents

Description

The invention relates to a thermophotographic recording material, consisting of a layer support and one or more layers applied to it, in or in those light-sensitive silver halide and an image-forming combination with (a) one of a heavy metal salt existing oxidizing agent and (b) .one of a bisnaphthol existing reducing agent is or are included.

It is known e.g. * Develop B from the US Patent 3,152,903 '& and 3,152,904, light-sensitive photographic materials by dry methods while heat. Such recording materials contain, inter alia, a reducing agent, for example a l-phenyl-3-pyrazolidone, hydroxylamine compounds, aminophenols, diphenols, for example pyrocatechol or resorcinol, aromatic esters, for example methyl gallate, or aromatic diamines, for example phenylenediamine, oxalates, formates or ascorbic acid.

It is also known, for example from the USA patent 3,094,619, for the production of photographic images by developing by dry means thermophotographic recording materials to use which contain a reducing agent which inactivates on imagewise exposure to UV light is.- In the case of the thermophotographic recording material known from US Pat. No. 3,094,619 the reducing agent consist of 1,1'-dihydroxy-2,2'-binaphthol. From US Pat. No. 3,080,254 there is also a thermophotographic recording material very similar to the thermophotographic recording material known from US Pat. No. 3,094,619 Recording material known which as a reducing agent is an α- or ß-naphthol together with 1- (2H-phthalazinone as toner contains »

Finally, it is also known, for example from US Pat. No. 2,165,421, 1,3-dihydroxybenzene compounds together with aliphatic aldehydes in photographic light-sensitive materials for hardening gelatin use.

It has also been shown that the simultaneous use of 1,3-dihydroxybenzene compounds, for example 2,4-dihydroxybenzaldehyde, and an oxidation-reduction image generator System in photosensitive materials that are developed by the action of heat does not belong to that leads to the desired increase in relative sensitivity and / or maximum density.

The object of the invention is to provide a thermophotographic recording material indicate that after the image-appropriate exposure by the action of heat in the usual known Way can be developed, however, of the previously known thermal photographic recording materials by a increased relative sensitivity and images of higher maximum density with increased exposure latitude without Increasing the minimum density provides.

The invention is based on the knowledge that combined Use of a bisnaphthol and a 1,3-DinyaVoxybenzo1verbindungen as reducing agents in thermophotographic recording materials those with a surprisingly increased relative Sensitivity can be obtained resulting in images with increased maximum density and expanded exposure latitude lead without increasing the minimum density if they are developed in the usual way by the action of heat.

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The invention is thus a thermophotographic Recording material, consisting of a layer support and one or more layers applied thereon in which or in which light-sensitive silver halide and an image-forming one Combination with (a) one of a heavy detailζ existing oxidizing agent and (b) a reducing agent consisting of a bisnaphthol is contained, which thereby is characterized in that the material contains a 1,3-dihydroxybenzene derivative as a second reducing agent in at least one layer.

As bisnaphthols, for example bisnaphthols of the following can be used given structural formula can be used:

(D

HO

OH

where mean:

R ₁ and Rj each represent a hydrogen atom or an alkyl radical having 1 to 3 carbon atoms or an alkoxy radical having 1 to 2 carbon atoms or a halogen atom or a nitro or amino radical and

η = 0 or 1.

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2,2'-Dihydroxy-1,1'-binaphthyl has proven to be a particularly suitable bis-ß-naphthol the following structural formula:

OH

Others for making thermophotographic recording materials Bis-naphthols particularly suitable according to the invention are, for example:

6,6'-Dibromo-2,2'-dihydroxy-1,1 ^f -binaphthyl 6,6 · -Dinitro-2,2 · -dihydroxy-1,1 · -binaphthyl bis (2-hydroxy-1-naphthyl) methane 6,6 '~ diethoxy-bis / ~ 2-hydroxy-1-naphthyl-7-methane 6,6'-diamino-2,2-dihydroxy-1,1 -binaphthyl 6,6'-dimethyl-2,2'- dihydroxy-1, I ¹ -binaphthyl and 6,6 * -dirnethoxy-2,2'-dihydroxy-1,1 · -binaphthyl.

Particularly advantageous 1,3-dihydroxybenzene derivatives for the production thermophotographic recording materials after of the invention can be represented by the following structural formula:

OH

C = O

R.

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wherein R, a hydrogen atom, an alkyl radical with preferably 1 to 6 carbon atoms or an aryl radical, preferably of the phenyl series.

Optionally, these can be 1,3-dihydroxybenzene derivatives, in particular the benzene nuclei of these compounds can be further substituted. Examples of making the thermophotographic 1,3-dihydroxybenzene derivatives suitable for recording materials are:

2,4-dihydroxybenzaldehyde, 2,4-dihydroxybenzophenone, 2 ¹ , 4 * -dihydroxyacetophenone, 2 ', 4'-dihydroxy-4-methylbenzophenone, 2 ¹ , 4'-dihydroxypropiophenone and 2', 4'-dihydroxybutyrophenone.

The combination of reducing agents used according to the invention thus forms a component of a thermophotographic Recording material consisting of a support, a photosensitive component, i.e. a photosensitive Silver halide, a bisnaphthol reducing agent and a 1,3-dihydroxybenzene derivative.

The oxidizing agent consisting of a heavy metal salt can from one of the thermophotographic recording materials common heavy metal salt exist, in particular a heavy metal salt of an organic acid. In doing so, are preferred uses heavy metal salts of organic acids which are resistant to exposure, d. H. not when exposing become dark »so that the exposed and developed images are not destroyed after development.

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As a particularly advantageous class of heavy metal salts, organic Acids, the silver salts of long-chain fatty acids, which are insoluble in water, have proven to be particularly light-stable are. Particularly advantageous such silver salts are, for example, silver behenate, silver stearate, silver oleate, silver laurate, Silver hydroxystearate, silver caprate, silver myristate and silver palmitate.

Other suitable carboxylic acid silver salts used as oxidizing agents can be used and are not silver salts of long-chain fatty acids are, for example, silver benzoate, SiI-ber-4'-n-octadecyloxydiphenyl-4-carboxylate, Silver o-aminobenzoate, silver acetamidobenzpate, silver furoate, silver camphorate, Silver p-phenyl benzoate, silver phenyl acetate, silver sal ^ cylate, Silver butyrate, silver terephthalate, silver phthalate, silver acetate and silver hydrogen phthalate.

Finally, compounds can also be used as oxidizing agents that do not consist of silver salts of carboxylic acids, for example silver compounds such as silver phthalazi-. non, silver benzotriazole and silver saccharin. Finally, oxidizing agents that can also be used are those that are not consist of silver salts such as zinc oxide, gold stearate, mercuribehenate, auribehenate and the like. As special However, the use of silver salts has proven advantageous.

The light-sensitive silver halide of the thermal photographic recording material according to the invention can be composed of any one of the usual ones for the production of thermophotographic recording material The silver halide used consists, for example, of silver chloride, silver bromide, silver bromide iodide, silver chloride bromide iodide or mixtures thereof. The light-sensitive silver halide can be coarse-grained or fine-grained. Very fine-grain emulsions have proven to be particularly advantageous.

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For the production of the thermophotographic recording materials according to the invention can be made from heavy metal salts existing oxidizing agents and the light-sensitive silver halides are used in usual concentrations »As It has been found to be useful per mole of heavy metal salt about 0.005 to about 0.50 moles of silver halide in the existing oxidizing agent.

The for the production of the thermophotographic recording material:] all photosensitive silver halides used in the invention can be prepared, sensitized, stabilized or otherwise treated according to customary known methods will.

The combination of reducing agents can be in different concentrations can be applied. It has proven to be particularly advantageous to use 0.4 to 2.0 moles of the reducing agent combination to be used per mole of photosensitive silver halide. According to a particularly advantageous embodiment of the invention 0.01 to 0.50 moles of photosensitive silver halide per mole of a heavy metal Isalζ existing oxidizing agent and 0.42 to 2.0 moles of bisnaphthol per mole of oxidizing agent with a molar ratio of bisnaphthol to 1,3-dihydroxybenzene derivative from 10: 1 to 1: 5 used.

The most favorable concentration ratios in the individual case can easily be determined by means of a series of experiments.

Apart from the combination of reducing agents according to the invention the thermophotographic recording materials according to the invention can thus, for example, have a structure as known from US Patents 3,457,075 and 3] 52,904 and from Belgian Patent 766,589 is.

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Optionally, for the production of the thermophotographic Recording materials according to the invention in addition to the bisnaphthols and 1,3-dihydroxybenzene derivatives described other reducing agents can be used. These additionally used Reducing agents can, for example, be made from silver halide developer compounds consist, for example of polyhydroxybenzenes, z. B. hydroquinones, phenylenediamines, aminophenols, Ascorbic acids and ascorbic acid derivatives, hydroxylamines, 3-pyrazolidones, hydroxytetronic acids and hydroxytetronimides, as well as developer connections consisting of reductones.

It can optionally be advantageous to use the layers of the thermophotographic recording materials according to the invention incorporate other customary additives, for example so-called activator toners to achieve deep black or even more neutral black images, stabilizers and stabilizer precursor compounds and the same. In addition, the usual known colloidal binders and / or synthetic polymers as binders, various common organic and inorganic hardeners, Plasticizers' and softeners, surface-active compounds, matting agents, optical brighteners, light-absorbing agents Substances and compounds that increase sensitivity are used. Finally, the thermophotographic Recording materials according to the invention also have customary antistatic or conductive layers.

Typical for the production of the thermophotographic recording materials According to the invention suitable activator-toner compounds are heterocyclic compounds with at least a nitrogen atom of the following structural formula:

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I ⁴

O = C * Z

mean:

R ^ eiaa hydrogen or metal ion ;, ζ * Β * a potassium,

, Sodium, lithium ₃ silver ₃ gold or mercury ion, or a hydroxyl group and

Z those to complete a heterocyclic nucleus, especially a 5- or 6-membered heterocyclic nucleus, required atoms »

The ones required to complete a heterocyclic nucleus For example, atoms can be a group of the following formula

-C-CR ₇ -CH-- U 2 2

or form an alkylene group having three or four carbon atoms. The atoms forming the heterocyclic nucleus can optionally substituted, for example by amino or alkylamino radicals, ζ. B. methylamine or ethylamino radicals, or by hydroxyl or carbamyl radicals.

Have beneficial activator-toner compounds as sponges heterocyclic compounds having at least one nitrogen atom, preferably consisting of a cyclicimide of the following Formula:

R,

o-c

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exists, proven. In this formula represent:

R _{5 is} a hydrogen or metal ion, for example a

Potassium, sodium, lithium, silver, gold or mercury ion, or a hydroxyl residue and

Z the atoms required to complete a cyclic imide nucleus, preferably such a cyclic imide nucleus which is formed from 5 or 6 carbon atoms, e.g. B. a phthalimide or succinimide core. The atoms of these cyclic imide nuclei can optionally be substituted, in particular by amino or alkyl radicals, in particular those with 1-5 carbon atoms, for example by methyl, ethyl, propyl, butyl or pentyl radicals, or by aryl radicals, especially by aryl radicals 6 to 20 carbon atoms, for example of the phenyl or naphthyl series, e.g. B. by phenyl, tolyl or xylyl radicals.

Typical advantageous activator-toner compounds that can be used in the context of the invention are, for example:

Phthalimide, N-hydroxyphthalimide,

N-Kaiiumphthal imid ,

N-silver phthalimide,, ^ N-mercury phthalimide, Succinimide and / or N-hydroxysuccinimide.

Together with or instead of the activator-toner compounds described, consisting of cyclic imides, it is of course also possible to use other activator-toner compounds. Typically, for example, widely heterocyclic organic toner compounds with at least two heteroatoms, ie heterocyclic ring, of

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at least one of which is a nitrogen atom can be used. Such organic toner compounds are for example in U.S. Patents 3,080,254 and 3,446,648. They consist, for example, of phthalazinone, phthalic anhydride, 2-acetylphthalazinone and 2-phthalylphthalazinone.

The activator-toner compounds described can be used in customary known concentrations can be used, preferably at concentrations of from about 0.10 to about 1.05 moles per mole Oxidizing agent.

It has also proven advantageous to incorporate a so-called image stabilizer or a compound which produces an image stabilizer, A, h. to incorporate a so-called stabilizer precursor compound. By using these compounds, it is possible, if necessary, to avoid or at least reduce copying out after the wrapping due to the effect of room light or the occurrence of background discoloration. Typical suitable stabilizer precursor compounds are, for example, azolethione ethers and so-called blocked azolthione stabilizers based on compounds, e.g. B ..: 5-acetyl-4-methyl-2- (3-oxobutylthio) thiazole; 4-furoyl-3-methylthio-1,2,4-thiadiaz61-5-thione; 5-acetyl-4-methyl-3- (3-oxobutyl) -thiazolin-2-thione and 2,6-di-tert-butyl-4- (1-phenyl-5-tetrazolyl) -thiophenol.

The stabilizers and stabilizer precursor compounds can be used in conventionally known concentrations, in particular in concentrations of about 0.002 to about 0.10 moles per mole of oxidizing agent, ζ. B. per mole of silver behenate.

For the production of the thermophotographic recording materials According to the invention, the customary known film supports can be used, for example film supports

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made of cellulose nitrate, cellulose esters, polyvinyl acetate, polystyrene, Polyethylene terephthalate, polycarbonates and other polymers as well as made of glass, paper, metal and the like. Flexible layer supports, in particular also paper layer supports, which have been partially acetylated, are of particular importance can, or can have a barite layer and / or a layer composed of an α-olefin polymer, in particular a layer from a polymer of an α-olefin having 2 to 10 carbon atoms, for example a layer of polyethylene, polypropylene, ethylene-butene copolymers and the like.

If necessary, non-aqueous, polar, organic solvents, for example compounds with a -C-, -S- or -S0 ₇ group, can also be used for the production of the thermophotographic recording materials according to the invention, 0 0

since these are often able to increase the maximum image density even further. Typical suitable such non-aqueous solvents are, for example, tetrahydrothiophene-1,1-dioxide, 4-hydroxybutanoic acid lactone and methylsulfinylmethane.

In order to increase the maximum image density, divalent metal salts which have the property that used to reinforce developed images. Typical such divalent metal salt image intensifiers are, for example Zinc acetate, cadmium acetate and cupric acetate. Such connections can, for example, in concentrations of from about 0.005 to about 0.20 moles per mole of oxidizing agent, in particular Silver salt oxidizing agents can be used. Particularly advantageous concentrations are from about 0.010 to about 0.10 moles per mole of oxidizing agent.

Optionally the photosensitive or photosensitive Silver halide also "in situ" in thermophotographic

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-, 13 -

Recording material are generated, for example by a method as is known from US Pat. No. 3,457,075 is. For example, a dilute solution of a halogen acid, for example a solution of hydrochloric acid, on the surface of a thin layer containing an organic silver salt, for example silver behenate, and on applied to a suitable support, after which the solvent can be removed. To this Silver halide is produced "in situ" over the entire surface before the layer of the organic silver salt.

The light-sensitive or photosensitive silver halide can furthermore be produced on or on the oxidizing agent, for example silver behenate or silver stearate or another organic silver salt, before the silver halide is applied to the layer support. Such a method is known, for example, from US Pat. No. 3,457,075. For example, an ilalogic acid, e.g. B. hydrochloric acid or hydrobromic acid, are mixed with an organic silver salt in a suitable reaction medium. A halide salt _9, which is more soluble than the organic silver salt, is then added to a suspension of the organic silver salt for the purpose of forming silver halide. Aqueous reaction media or other solutions which do not interfere with the reaction can be used for this purpose.

Particularly before being copied out by the action of light, recording materials which are stable can be achieved by using highly pure Starting materials are obtained, especially those that are free from halides and sulfides. By using high purity Silver behenate, for example, can be used to copy out the Kinter ^ round areas of a recording material according to the invention can be greatly reduced.

For the production of the thermophotographic recording materials according to the invention can also the most diverse common known spectral sensitizing color

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fabrics are used. The most favorable concentration in the individual case the same depends on the desired spectral sensitivity, other components of the recording materials, the desired image, developing conditions and the like. It has proven to be useful to use spectrally sensitizing Dyes in concentrations of from about 50 mg to about 2 g per mole of catalyst, e.g. B. per mole of photosensitive silver halide, to use. Particularly advantageous thermophotographic Recording materials according to the invention are characterized in that they contain:

a) light-sensitive silver halide,

b) silbefoehenate,

c) 2,2'-dihydroxy-1,1'-binaphthyl,

d) 2,4-dihydroxybenzaldehyde, 2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone,

e) phthalimide,

f) 5-acetyl-2-benzyloxycarbonylthio-4-methylthiazole and

g) 3-Carboxymethyl-5- / ~ (3-methyl-2 (3II) -thiazolinylidene) -isopropylidene_7rhodanine.

After exposure, the photothermographic recording materials of the present invention, the latent images thus obtained can be used in a conventional manner by simply heating the recording material to temperatures of about 80 to about developed 25O ⁰ C.

Temperatures of about 120 to 180 ^° C. are preferably used for the development. By increasing or decreasing the heating time, higher or lower temperatures can be used within the specified range. As a rule, imagewise exposed thermophotographic recording materials according to the invention can be produced within a few seconds,

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for example within 0.5 to about 60 seconds, in particular develop within 0.5 to 5 seconds.

The development can take place under normal pressure and humidity conditions take place. However, the development can, if necessary, also be carried out under pressure and humidity conditions that are outside of normal atmospheric conditions. Preferably, however, be atmospheric Conditions applied.

The heating of the exposed recording materials can be carried out in done in a conventional manner, for example by using usual simple heating plates, by iron or heating rollers.

It may be advantageous to use the silver halide des Recording material in one layer and the other components to be accommodated in other layers. For example, a thermophotographic recording material according to the Invention also consist of a support, furthermore a layer with light-sensitive photographic silver halide and a layer with the so-called thermographic combination, consisting of:

a) an oxidizing agent consisting of a heavy metal salt, - -

b) the described reducing agent combination and

c) preferably an activator-toner compound.

Of course, the layers can also contain other customary additives.

According to an advantageous embodiment of the invention, the oxidizing agent consists of a heavy metal salt thermophotographic recording material made of silver behenate and the reducing agent combination of 2,2'-dihydroxy-1,1'- "

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binaphthyl and a 1,3-dihydroxybenzene derivative from 2,4-dihydroxybenzaldehyde, 2,4-dihydroxybenzophenone and / or

2 ', 4'-dihydroxyacetophenone.

In the manufacture of the thermophotographic recording materials According to the invention, the active components of the layer or layers of the thermophotographic recording material dispersed in common known binders or are dissolved in a known manner using solvents. Typical ones that can be used in an advantageous manner Binders are binders based on polyvinyl butyral.

The following objects are intended to further illustrate the invention.

example 1

First, a photosensitive silver halide-silver behenate dispersion was prepared manufactured. For this purpose, the components listed below were first used for 72 hours in one Grinding ball mill:

Silver behenate behenic acid polyvinyl butyral Phthalimide

Acetone-Toluo1 mixture (Volume ratio 1: 1)

After grinding, 150 ml of a 1.0 wt. Algae lithium bromide solution were added in acetone was added, whereupon the mixture obtained was stirred for a further 16 hours. That way obtained light-sensitive silver halide-silver behenate dispersion is referred to as dispersion I in the following.

84 , 0 G 64 , 0 G 30th , 0 G 17th , 0 S. 1000 , 0 ml.

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2.0 ml of Dispersion I were then made with the following components mixed:

1.0 ml of a 0.01% strength by weight acetone solution of a sensitizing dye

2.0 ml of a 5.0% strength by weight solution of a bisnaphthol derivative in acetone

0.5 ml of a 1 wt. -! igen S-Acetyl - ^ - beiizoyloxycarbonylthio-4-methylthiazole solution in acetone

0.3 ml of a 5.0% strength by weight solution of a 1,3-dihydroxybenzene derivative in methanol or acetone and

8.0 ml of an acetone-toluene mixture in the weight ratio " 1: 1.

The dye consisted of 3-carboxymethyl-5- / ~ 3-methyl-2 (3H) -thiazolinylidene) isopropylidene_7rhodanine.

The ßisnaphthole and 1,3-dihydroxybenzene derivatives used are compiled in Table I below.

The photosensitive coating compositions obtained were then applied to conventional photographic paper supports in a thickness, measured wet, of about 0.010 cm. The recording materials were then exposed for 1 second in a conventional contact copier with a tungsten lamp. The exposed thermal photographic recording materials were then heated by bringing the side opposite the photosensitive side of the recording material into contact with a heating block made of metal. The heating time was approximately 4 seconds with a heating block temperature of 145 ° C.

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1 Q J. ο

There were the D and D. -Reflection densities as well as the different sensitivities (visible levels of the exposure scale) determined. The results obtained are summarized in the following table 1:

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Ee stratification s- ^ mass No. '

O CO OO

ßisnaphthol

Ψ,

Table 1

1,5-dihydroxybenzene reflection densities

Max

min

Exposure scale visible steps

II

ßr

-CII,

NH ₉ NH-,

Br

-CH.

II

-CH ₂ CH ₂ CH ₃ - (CH ₂ )

NH,

NILE

O O O

O O

H
H
H

0 ethyl C-CH ₂ CH ₃ )

1 propyl (-CH

1.40 black

deep black

black Cl, 28)

black

deep

black

deep black (1.54)

deep black

1.30

0.02

yellow-brown white

beipe (0.37)

yellow-brown

White

White

(0.14

white 0.02

11

10

11

10 10

Example 2

The procedure described in Example 1 was repeated with the exception that

a) other bisnaphthols and other 1,3-dihydroxybenzene derivatives used xvurden and that also

b) the obtained thermophotographic recording materials Were brought into contact with a metal block heated to a temperature of 135 ° C. for 7 seconds.

The results obtained are shown in Table 2 below :

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Coating ^R l Bisnaphthol η Table 2 Reflection densities Beiich-
_ ^^ 4 4> v ^ f * rf ^ ^ 4 '1 rr \ ^ x *** management
mass no. H R ₂ 1 DD. ■
max mm tungssKaia 10 -OH H 0 1,3-dihydroxybenzene deep black white stages 11 H 3 3 0 ^R 3 deep black white 11 12th H H 1.36 0.02 10 H 1 H 11 Mt 13th H H deep black white * O ' 11 CO
* · '
* »·
O Phenyl t- ^ ^ J

-OCH ₂ CH ₃ -OCH ₂ CH ₃ 1 phenyl-4-methyl

1 methyl C-CH ₃ )

ti · * · «* ™» % * Z, Ur .9 deep black "white

Comparative example

The procedure described in Example 1 was repeated with the exception, however, that at least one of the reducing agents was omitted. The heating temperatures used in the individual case and the heating times as well as those obtained in this way The results are summarized in the following table 3:

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Coating Bisnaphthol H p η 1,3-di
hydroxy Erhit Table 3 Reflection densities Max j) min Coating
management management - ^K 2 0 benzene. tion Erhit
tongue s- T) 0.21 0.02 scale mass no. 1 H H - ^R 3 duration ■ tempe ~ ₀ 0.14 0.02 visible 16 NH ₂ - 0 - temperature C 0.59
0.04 0.02
0.02 stages 17th - H 0 H 4 sec. 145 0.47 0.02 8th 18th
19th H NH ₂ - H 4 sec. 145 Ό, 14 0.02 7 "■ 20th 0 - 7 sec.
7 sec. 135
135 1.24 0.02 9
4th O
co
00 21st H H 7 sec. 135 6th ο 22nd - 15 sec. 135 6th 15 sec. 135 8th

221230?

A comparison of the results of Examples 1 and 2 with the results of Comparative Example 3 shows that the photothermographic recording materials of the invention show a surprising increase the maximum density and the exposure latitude, the broadening de _t s Belichtungsspeilra.umes by the larger number visible steps on the exposure scale.

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Claims (9)

PATENT RANKS LyThermophotographic recording material, consisting of a support and one or more layers applied to it, in which or in which light-sensitive silver halide and an image-forming combination with (a) an oxidizing agent consisting of a heavy metal salt and (b) a reducing agent consisting of a bisnaphthol is or ., characterized in that the material contains a 1,3-dihydroxybenzene derivative as a second reducing agent in at least one layer. 2. Thermophotographic recording material according to claim 1, characterized in that it is a 1,3-dihydroxybenzene derivative of the following structural formula as the second reducing agent contains: OH in which R, a hydrogen atom, an alkyl radical or a Represents aryl radical. 40ta 3. Thermophotographic recording material according to claims 1 and 2, characterized in that it contains a total of 0.4 to 2.0 moles of reducing agent per mole of silver halide. 4. Thermophotographic recording material according to claims 1 to 3, characterized in that the ratio of bisnaphthol to 1,3-dihydroxybenzene derivative is 10: 1 to 1: 5. 5. Thermophotographic recording material according to Claims 1 to 4, characterized in that there is per mole of heavy metal salt oxidizing agent Contains 0.01 to 0.50 moles of photosensitive silver halide. 6. Thermophotographic recording material according to Claims 1 to 5, characterized in that it additionally contains a stabilizer precursor compound contains. 7. Thermophotographic recording material according to claim 6, characterized in that it is 0.002 per mole of oxidizing agent contains up to 0.10 moles of stabilizer precursor compound. 8. Thermophotographic recording material according to claims 1 to 7, characterized in that there is also an activator-toner compound contains. 9. Thermophotographic recording material according to claim 8, characterized in that it contains phthalimide or phthalazinone as the activator-toner compound. 209840/1032