DE2511361A1 - HEAT DEVELOPMENT LIGHT SENSITIVE MATERIAL - Google Patents

Description

PATENT ADVOCATES A. GRÜNECKER

wi — ing

H. KINKELDEY

CKt-ING.

OC11OC1 W. STOCKMAIR

L 0 II S3 0 I DR-ING A ^ (CAUiCH

K. SCHUMANN

_% ORBBlNAr OPL-PHKS

P. H. JAKOB

DtPL-ING

β. BEZOLD

OR. HER N / VT-DtPL-CHBW.

MUNICH

E. K. WEIL

Dn RER oea ing

8 MUNICH 22

MAXIMILIANSTRASSE 43

March 14, 1975 P9024

Fuji Photo Film Co., Ltd.

No. 210, Nakanuma, Minami Ashigara-Shi, Kanagawa, Japan

LINDAU

Heat developable photosensitive material

The invention relates to heat developable photosensitive material, and more particularly to heat developable photosensitive material Material that leads to black images, and from which a lesser one Heat fog (fog formed in the unexposed areas when heated) occurs.

Photographic processes using silver halide are widely used because they have superior photographic properties, for example good speed or gradation compared to other photographic processes such as electrophotography or the diazotype. The silver halide photographic material used in these processes

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TELEPHONE (Ο89) 22 38 62 TELEX OS-SSSBO TELEGRAMS MONAP

however, after imagewise exposure the development will take Subjected to the use of a developer and then to various processing stages, such as stopping, fixing, washing or stabilization, so that the developed images do not become discolored or faded in normal Room lighting occur and no blackening of the undeveloped areas (hereinafter referred to as the background) takes place. These methods are thus time consuming and laborious. Other problems are that the handling of the The chemicals used poses hazards to the human body, and the hands and clothes of workers, as well the processing rooms are soiled or stained by processing. It is therefore very desirable to use the photographic Process using silver halide to improve processing in a dry state without application of processing solutions, and the processed images are preserved in a stabilized state can be.

Numerous efforts have already been made to overcome the aforementioned difficulties. One method is there in the use of heat developable em photosensitive Material, as in the published JA-PA 41 865/71, the U.S. Patents 3,152,904, 3,457,075, 3,635,719, 3,645,739, 3,707,377, 3,802,888, 3,704,329, 3,672,904, 3,846,136, 3,708,304, 3 761 279, 3 751 249, 3 770 448 and 3 773 512, the CA-PS 811 677, the BE-PS 765 452 and the JA-PA 318/73 and 89 720/73.

The method described in the aforesaid patent literature involves the use of a photosensitive element which a silver salt, for example a silver salt of a higher fatty acid, such as silver behenate, silver saccharin (o-sulfobenzoic acid imide) or silver benzotriazole as the main component, as well as one catalytic amount of a photosensitive silver halide · contains.

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In these heat developable photosensitive materials however, when heating after the imagewise exposure, the unexposed areas become blackened (hereinafter referred to as heat fog labeled), so that it is difficult to read or recognize the images, because the contrast between the exposure - " and the blackened non-image area (image density) is decreased.

An important problem is the reduction of this heat curtain. The most effective measure to overcome this The disadvantage is the use of a mercury compound, as described in the published JA-PA 11 113/72. As is well known however, mercury compounds are highly toxic, so that their use is relatively dangerous. So occurs for example When heated, the mercury evaporates, or the mercury is leached out when the waste of the mercury compounds containing material recycled.

On the other hand, it is known, for example from US Pat. No. 3,589,903, that phthalazinones are most effective for blackening the color of images in heat developable photosensitive Material are. The presence of phthalazinones in heat developable photosensitive material, however, has a significant impact Reinforcement of the heat veil with it, although the images turn black.

It is therefore an object of the invention to provide heat developable To provide photosensitive material that has little tendency to heat fog.

Another object of the invention is to provide heat developable To provide photosensitive material that is non-toxic.

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Another object of the invention is to provide heat developable to provide photosensitive material, which produces black images after exposure and development.

Another object of the invention is to provide heat developables To make light-sensitive material available, which has only a low tendency to form thermal fog and results in black images upon exposure and development.

It has now been found that the aforementioned objects can be achieved by using a phthalazinone and a sulfinic acid or a salt thereof is used.

The subject of the invention is thus heat developable photosensitive Material, which is characterized by a carrier and, located thereon, at least one layer with at least (a) a silver salt of an organic carboxylic acid, (b) a photosensitive silver halide or a component, which is able to form a light-sensitive silver halide upon reaction with the silver salt of the organic carboxylic acid (a), (c) a reducing agent, (d) at least one phthalazinone, and (e) at least one sulfic acid and / or a salt of this.

The silver salts of organic carboxylic acids used according to the invention as component (a) (hereinafter also referred to as organic carboxylic acid silver salts) are essentially colorless silver salts which are stable to light and which react with the reducing agent when heated to above 80 ^° C., preferably above 100 ⁰ C, produce silver images in the presence of exposed silver halide catalyst.

Examples of suitable organic carboxylic acid silver salts are silver salts of higher fatty acids (such as silver caprate, laurate,

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myristate, palmitate, stearate and behenate), silver salts of Dicarboxylic acids, such as silver adipate and sebacate, and silver salts of aromatic carboxylic acids, such as silver benzoate, -3 »5-dihydroxybenzoate, -o-methylbenzoate, -m-methylbenzoate, -p-methylbenzoate, -2,4-dichlorobenzoate, gallate, tannate, phthalate, terephthalate and salicylate.

Suitable processes for the preparation of the organic carboxylic acid silver salts (a) consist in that an aqueous solution of a water-soluble salt of an organic carboxylic acid (for Example an alkali metal salt, such as a sodium, potassium or Lithium salt, or an ammonium salt) with an aqueous silver- nitrate solution mixed, resulting in the desired silver salt; a solution of an organic carboxylic acid in solvents, which dissolve the organic carboxylic acid, but not or only not the organic carboxylic acid es.ilbers al ζ and silver nitrate Poorly dissolve and are poorly soluble in water (for example phosphoric acid esters, such as tricresyl phosphate, tributyl phosphate and Monooctyl dibutyl phosphate; Phthalic acid esters such as diethyl phthalate, dibutyl phthalate, dimethyl phthalate, dioctyl phthalate and dimethoxyethyl phthalate; Carboxylic acid esters, such as amyl acetate, isopropyl acetate, isoarayl acetate, ethyl acetate, 2-ethylbutyl acetate, Butyl acetate, propyl acetate, dioctyl sebacate, dibutyl sebacate, Diethyl sebacate, diethyl succinate, ethyl formate, propyl formate, Butyl formate, amyl formate, ethyl valerate, diethyl tartrate, methyl butyrate, Ethyl butyrate, butyl butyrate and isoamyl butyrate; Glycerol esters of higher fatty acids such as castor oil; aromatic hydrocarbons such as benzene, toluene and xylene; η-hexane or Cyclohexane, etc.) or, if necessary, an emulsion of this solution in water or an aqueous alkaline solution (for Example of an aqueous sodium hydroxide, potassium hydroxide or ammonia solution) with an aqueous silver nitrate solution or an aqueous solution of a silver complex salt (preferably a silver complex salt soluble in alkaline solution with a dissociation constant larger than that of the organic carboxylic acid silver salt, for example one

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Silver-ammine complex salt, silver-methylammine complex salt or silver-ethylamine complex salt) mixed, the organic Carboxylic acid silver salt is formed; or an emulsion of an aqueous solution of the organic carboxylic acid salt (for Example of the sodium, potassium or ammonium salt) and the aforementioned, Solvents that are poorly soluble in water, with an aqueous solution of a silver salt, for example silver nitrate or a silver complex salt, mixed, whereby the desired organic carboxylic acid silver salt is formed.

These processes for the preparation of organic carboxylic acid silver salts are disclosed in U.S. Patent 3,458,544, published U.S. Patent No. 3,458,544. JA-PA 30 270/69, the JA-PA 49 436/72, 48 453/72, 43 867/72, 7619/73 and 9362/73, as well as the FR-PS 2 147 286 described.

In the photosensitive silver halide component used in the present invention (b) it can be silver chloride, silver bromide, silver bromoiodide, silver iodobromochloride, silver bromochloride, Silver iodine chloride, silver iodide or mixtures of the aforementioned Act silver halides.

The photosensitive silver halides can be act coarse-grained or finely divided silver halides; finely divided Silver halides are preferred, with particle sizes of about 50 to 5000 Å, in particular 100 to 1000 Å, being preferred will. The photosensitive silver halides can be prepared according to known methods Process are produced. Examples of suitable methods are single-jet methods, double-jet methods, for Example Lipmann emulsions, ammonia processes and ripening processes using thiocyanates or thioethers, as described in U.S. Patents 2,222,264, 3,320,069 and 3,27,1157.

Process for preparing the photosensitive silver halide component (b) which are well suited for the heat developable photosensitive material of the invention are as follows described in detail.

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One method is to add a silver halide simultaneously with the formation of the organic carboxylic acid silver salt component (a) Produced by using a component containing silver halide during the preparation of the organic Forms carboxylic acid silver salt component (a). According to this process, a heat developable photosensitive material is obtained with improved photosensitivity, which leads to clear images with good contrast, since there is sufficient contact of the organic carboxylic acid silver salt with the silver halide. This procedure is described in JA-PA 65 727/73.

Another method for producing the photosensitive silver halide is described in U.S. Patent 3,457,075. The procedure here is to form a silver halide Component, for example a compound producing halogen ions, in vapor form or in solution with a previously prepared one organic carboxylic acid silver salt component (a) reacted in order to convert part of the organic carboxylic acid silver salt component (a) to convert into a catalytic amount of the silver halide component (b). This process can also be used to produce photosensitive materials Material with high sensitivity can be obtained.

Another method of making catalytic amounts of silver halide described in U.S. Patent 3,152,904 consists in preparing silver halide beforehand and this silver halide with an organic carboxylic acid silver - salt mixed.

Any compound can be used as the silver halide-forming component can be used so long as it forms silver halide by reaction with the organic carboxylic acid silver salt component (a). Effective silver halide-forming components can easily be determined, for example by looking after the reaction a silver halide-forming component with an organic carboxylic acid silver salt, optionally with heating, using an X-ray diffraction method to determine whether the

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has formed a diffraction peak characteristic of silver halide.

Suitable silver halide-forming components have, for example, the general formula

MX _n

in which M is a hydrogen atom, an ammonium group or a metal atom (for example a strontium, cadmium, zinc, tin, chromium, sodium, barium, iron, cesium, lanthanum, copper, Calcium, nickel, magnesium, potassium, aluminum, antimony, gold, cobalt, mercury, lead, beryllium, lithium, Manganese, gallium, indium, rhodium, ruthenium, palladium, iridium, platinum, thallium or bismuth atom) is; X is a halogen atom (preferably a chlorine, bromine or iodine atom); and η has the value 1 if M is a hydrogen atom or an ammo nium group, and η means the valence of the metal atom when M 'is a metal atom.

Further examples of silver halide-forming components are halogen-containing metal complexes, such as KpPtCIg, KpPtBrg, HAuCl ₄ , (NH ₄ J ₂ IrCl ₆ , (NH ₄ J ₃ IrCl 6, (NH ₄ J ₂ RuCl ₆ , (NH ₄ J ₃ RuCl ₆ , (NH ₄ J ₃ RhCIg and (NH ₄ J ₃ RhBr ₆ .

Additional · examples of silver halide-forming components are N — halogen compounds with a —CONX grouping (where X has the meaning Cl, Br or J). Examples of such compounds are N-haloacetamide, N-halophthalazinone and N-halosuccinimides of the general formula

R ^ N - X

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9 1. ι ι <· · I t

in which R denotes a radical which has a nitrogen-containing 5- or 6-membered heterocyclic ring, for example a Pyrrolidine, 3-pyrroline, pyridine or piperidine ring, completed, and X is Cl, Br or J.

Other N-halogen compounds, such as N-halogenobenzotriazole and substituted benzotriazoles are also effective.

Other suitable examples of silver halide-forming components are onium halides, for example cetylethyldimethyl- ammonium bromide and trimethylbenzylammonium bromide.

Halogenated hydrocarbons are considered to be silver halide-forming Components also effective. Examples of such coal. Hydrogens are iodoform, bromoform, carbon tetrabromide and 2-bromo-2-methylpropane.

Also halogen-containing compounds, such as triphenylmethyl chloride, Triphenylmethyl bromide, 2-bromobutyric acid, 2-bromoethanol and dichlorobenzophenone, can be used as the silver halide-forming component.

The foregoing compounds which are the photosensitive silver halide can be used either alone or in a combination of two or more compounds.

The silver halide or silver halide-forming component is preferably used in an amount of from about 0.001 to 0.5 mol, in particular 0.01 to 0.2 mol, each per mole of the or- Ganischen carboxylic acid silver salt component (a) is used. If the amount is less than about 0.001 mole per mole, the sensitivity is degraded. On the other hand, if the amount is more than about 0.5 mole per mole, discoloration under the action of light, occur and there may be a decrease in contrast between the Image area and the background come.

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According to the invention are as reducing agent coraponents (c) for Example organic reducing agents suitable which have a suitable reducing power for the organic carboxylic acid silver salt component (a) for the production of silver images under the catalytic effect of the "exposed silver halide component (b) in the exposed area when heated. the preferred reducing agents are selected according to the specific organic carboxylic acid silver salt component (a) with which the combination takes place. The reducing agent component (c) can be selected from the following classes of compounds:

1) monohydroxybenzenes,

2) dihydroxybiphenyls,

3) di- or polyhydroxybenzenes,

4) naphthols, naphthylamines and aminonaphthols,

5) hydroxybinaphthyls,

6) aminophenyls,

7) p-phenylenediamines,

8) alkylene biaphenols,

9) ascorbic acid and derivatives thereof, and 10) pyrazolidones.

Specific examples of the aforementioned compounds are

(1) monohydroxybenzenes, such as

p-phenylphenol, o-phenylphenol, p-ethylphenol, p-tert.-butylphenol, p-sec-butylphenol, p-tert-amylphenol,. p-methoxyphenol, p-ethoxyphenol, p-cresol, 2,6-di-tert, -butyl-p-cresol, 2,4-xylenol, 2,6-xylenol, 3,4-xylenol, p-acetylphenol, 1,4-dimethoxyphenol, 2,6-dimethoxyphenol, Hydroquinone mono-n-hexyl ether, hydroquinone monobenzyl ether and chlorothymolj

(2) dihydroxybiphenyls such as

3 »3 *, 5.5» -Tetra-tert-butyl-4,4'-dihydroxybenzene (3) Di- or polyhydroxybenzenes, such as

Hydroquinone, methylhydroquinone, tert-butylhydroquinone, 2, ^ 5-dimethylhydroquinone, 2,6-dimethylhydroquinone,

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tert-octylhydroquinone, phenylhydroquinone, methoxyhydroquinone, Athoxyhydroquinone, chlorohydroquinone, bromohydro- quinone, hydroquinone monosulfonic acid salts, pyrocatechol, 3-cyclohexylpyrocatechol, resorcinol, gallic acid, methyl- gallate and n-propyl gallate;

(4) naphthols, naphthylamines and aminonaphthols, such as s * v -naphthol, ß-naphthol, 1-hydroxy-4-ynethoxynaphthaiin, i-Hydroxy-4-ethoxynaphthalene, 1,4-dihydroxynaphthalene, 1,5-dihydroxynaphthalene, 1-hydroxy-2-phenyl-4-methoxynaphthalene, g-Hydroxy ^ -methyl ^ -methoxynaphthalin, Potassium-1- amino-2-naphthol sulfonate, 1-hydroxy-4-aminonaphthalene and 1-naphthylamine-7-sulfonic acid;

(5) hydroxybinaphthyls such as

1,1'-dihydroxy-2,2'-binaphthyl, 4,4'-dimethoxy-1,1'-dihydroxy-2,2'-binaphthyl, 6,6 ^f -dibromo-2,2'-dihydroxy-1 , 1 ^f binaphthyl, 6,6'-dinitro-2,2'-dihydroxy-1,1'-binaphthyl and bis (2-hydroxy-1-naphthyl) methane

(6) aminophenols such as

p-aminophenol, o-aminophenol, 2,4-diaminophenol, N-methyl- p-aminophenol, 2-methoxy-4-aminophenol and 2-ß-hydroxy- ethyl-4-aminophenol;

(7) p-phenylenediamines, such as

N, N ^f -diethyl-p-phenylenediamine and Ν, Ν'-dibenzylidene-p-phenylenediamine;

(8) alkylene bisphenols such as

1,1-bis- (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, 1,1-bis (2-hydroxy-3 »5-dimethylphenyl) -3,5 j5-trimethylhexane, 1,1-bis- (2-hydr.oxy-3 »5-di-tert-butylphenyl) -2-methylpropane, 2,2-bis- (^ hydroxy-S-methylphenyl) propane, 4,4- Bis- (4-hydroxy-3-methylphenyl) -heptane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) -propane, 2,2-bis- (4-hydroxy-3-phenylphenyl) -propane, 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 2,2-bis (4-hydroxy-3 »5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3 tert-butyl-5-methylphenyl) propane, 3,3-bis (4-hydroxy-3-tert-dodecylphenyl) hexane, (4,4 · dihydroxy-3-methyldiphenyl) -2, 2-propane, (4,4 ^1- dihydroxy-3-tert.-octyldiphenyl) -2,2-propane,

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(4,4'-Dihydroxy-3-tert-butyldiphenyl) -4-methyl-2,2-pentane, (4,4'-dihydroxy-3-methyl 1-3'-tert-butyldiphenyl) -2 , 2-propane, (4,4'-dihydroxy-3-methy 1-5-tert-butyldiphenyl) -2,2-propane, 2,2-bis- (4-hydroxyphenyl) -pfopan, (4,4 ^f -dihydroxy-3,3 ', 5-trimethy! diphenyl) -3,3 ~ pentane, N- (4-hydroxyphenyl) salicylarid, 2,2-bis- (3 »5-dibromo-4-hydroxyphenyl) - propane and bis (3-methyl-4-hydroxy-5-tert-butylphenyl) sulfide;

(9) ascorbic acid and derivatives thereof such as ^ -ascorbic acid, monoesters such as Z-ascorbic acid ethyl ester , and diesters such as ji-ascorbic acid diethyl ester; and

(10) pyrazolidones, such as

1-phenyl-3-pyrazolidone and 4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone.

The aforementioned reducing agents can either be used alone or can be used in combination of two or more compounds. The suitability of the reducing agent depends to a large extent on the reducibility of the organic carboxylic acid silver salt component used (a) from. In the case of silver salts of higher fatty acids, it is necessary, with increasing number of carbon atoms in the Acid to select a stronger reducing agent. A relatively weak reducing agent, such as p-phenylphenol, is for silver laurate suitable, while for silver behenate a relatively strong reducing agent such as 1,1'-bis- (2-hydroxy-3-tert-butyl-5-methylphenyl) methane, is preferred.

The amount of the aforementioned reducing agent component to be used (c) cannot be clearly determined from the outset, as this amount depends on the oxidation-reduction combination of components (a) and (c) depends. Generally, however, there is a range of about 0.1 to 5 moles of the reducing agent component (c), effective per mole of the organic carboxylic acid silver salt component (a), that is, the silver salt oxidizing agent.

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The together with the components (a) to (c) used phthalic azinonkomponente (d), which is one of the characteristic components of the invention, serves as Färbtonungsmittel "or color toner. Examples of such phthalazinones are phthalazinone itself, and in JA -PA 116 022/73 described substituted phthalazinones. Preferred Äthalazinones have the general formula I.

Ri Rs

in which R ₁ , Rp, R 1 and R ₄ each represent a hydrogen or halogen atom, an alkyl or alkoxy radical, a nitro, amino or hydroxyl group; R, - is a hydrogen or halogen atom, an alkyl radical, aryl radical, substituted alkyl radical, substituted aryl radical, benzylidene hydrazino, pyridyl, vinyl or 2-substituted vinyl group; and at least one of the radicals R ₁ , Rp >> R-Di R / and Rf- are an atom or a radical which is not a hydrogen atom.

In the general formula I, preferred examples of the radicals R ₁ , Rp »R ^ and R. are chlorine and bromine atoms for the halogen atoms, alkyl radicals with 1 to 4 carbon atoms, such as methyl, ethyl, propyl, butyl or tert-butyl groups for alkyl radicals and alkoxy radicals with 1 to 4 carbon atoms, such as methoxy, ethoxy, propoxy or butoxy groups, for alkoxy radicals. Preferred examples for R (- are chlorine and bromine atoms for halogen atoms; alkyl radicals with 1 to 4 carbon atoms, such as methyl, ethyl, propyl or butyl groups, for alkyl radicals; alkoxy radicals with 1 to 4 carbon atoms, such as methoxy- , Ethoxy, propoxy or butoxy groups, for alkoxy groups; phenyl, 1-naphthyl and 2-naphthyl groups for aryl groups; haloalkyl groups with 1 to 4 carbon atoms in the alkyl group, such as chloromethyl, bromoethyl, chloropropyl or chlorobutyl groups pen, hydroxyalkyl radicals with 1 to 4 carbon atoms in the alkyl radical, such as -hydroxymethyl-, ß-hydroxyethyl-, * f -hydroxypropyl- or

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a -Hydroxybutylgruppen, aminoalkyl radicals rait Ί to 4 carbon atoms in the alkyl radical, such as aminomethyl, aminoethyl or aminobutyl groups, dialkylaminoalkyl radicals with 1 to 4 carbon atoms in the alkyl radical ■ and alkyl radicals with 1 to 4 carbon atoms in the alkyl radical Dialkylamino substituents, such as dimethylaminomethyl or dimethylaminoethyl groups, aralkyl radicals with 1 to 4 carbon atoms in the alkyl radical, such as benzyl or phenethyl groups, alkoxyarylalkyl radicals with 1 to 4 carbon atoms in the alkyl radical and 1 to 4 carbon atoms in the alkoxy radical, such as p- Methoxybenzyl groups, and alkyl radicals having 1 to 4 carbon atoms, substituted by a morpholino group, for example one. Morpholinomethyl, morpholinoethyl, morpholinopropyl or morpholinobutyl group, as substituted alkyl radicals; Haloaryl radicals, such as chlorophenyl or bromophenyl groups, aryl radicals substituted with an alkyl radical having 1 to 4 carbon atoms, such as methylphenyl, ethylphenyl, butylphenyl or tert-butylphenyl groups, aminophenyl groups, and phenyl groups which are substituted by an amino group with alkyl radicals Contains 1 to 4 carbon atoms, such as dimethylaminophenyl groups, as substituted aryl radicals; and β-8tyryl, 2- (3-pyridyl) vinylidene and 2- (2-pyridyl) vinylidene groups as 2-substituted vinyl groups.

Specific examples of preferred compounds of the general Formula I are 4-methylphthalazinone, 4-phenylphthalazinone, 4- (1-naphthyl) -phthalazinone, 4- (2-naphthyl) -phthalazinone, 4-hydroxymethylphthalazinone, 4-chlorophthalazinone, 4-methoxyphthalazinone, 4-ß-styrylph.thalazinon, 4-dimeth.ylaminomethyl- phthalazinone, 4-morph.olinomethylphthalazinone, 4- (p-meth.oxy- benzyl) -phthalazinon, 4- (Benzylidenhydrazino) -phthalazinon, 4- (p-dimethylaminophenyl) phthalazinone, 4-benaylphthalazinone, 6-chlorophthalazinone, 5 »7-dimethoxyphthalazinone, 8-methylphthalazinone, 6-bromophthalazinone, δ-tert-butylphthalazinone, 5 — nitrophthalazinone, 8-aminophthalazinone, 8-hydroxyphthal— ■ azinone, 4- (p-chlorophenyl) phthalazinone and 4- (p-pyridino) -.

phthalazinone.

In addition, it is possible to combine the phthalazinones with other toners, such as phthalimides, oxazinediones,

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Pyrazolin-5-ones, quinazolinones and mercapto compounds, too use. These toners are disclosed in U.S. Patents 3,832,186 and US Pat 3,846,136; U.S. Patents 354 583/73 and 467 763/74, and U.S. Pat DT-OS 2 140 406 and 2 H1063 described.

The phthalazinone color toner is preferably used in an amount of about 0.0001 to 2 hol, in particular 0.0005 to 1 mol, in each case per mol of the organic silver salt component (a) is used. The sulfinic acids and sulfonic acid salts of component (e) of the invention preferably have the general formula II

R ₆ - SO ₂ X ₁ (II)

In the general formula II, R ₁ is a monovalent, aliphatic or aromatic radical, and X 1 is a monovalent, positive ion. Particularly preferred are those sulfinic acids and sulfinic acid salts of the general formula II in which Rg is an alkyl radical, a substituted alkyl radical, an aryl radical or a substituted aryl radical, and X ^ is a hydrogen atom, an alkali metal, alkaline earth metal or ammonium ion. Suitable alkyl radicals for R ^ - preferably have 6 to 22 carbon atoms, such as hexyl, heptyl, ethylhexyl, octyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl, eicosyl or docosyl groups · Preferred substituted alkyl radicals have 2 to 22 carbon atoms in the alkyl radical and carry halogen atoms (for example chlorine, bromine or iodine atoms), nitro groups, alkoxy radicals (preferably alkoxy radicals with 1 to 8 carbon atoms, such as methoxy, ethoxy, propoxy) as substituents -, butoxy, amyloxy, hexyloxy or octyloxy groups), hydroxyl groups, cyano groups, carbonxyl groups, amino groups or acetylamino groups. Examples of preferred aryl groups are phenyl groups and naphthyl groups, and examples of preferred substituted aryl groups are aryl groups which have alkyl groups as substituents (preferably alkyl groups with up to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl or octyl groups) , Halogen atoms (for example chlorine, bromine or iodine atoms), haloalkyl radicals (preferably haloalkyl radicals with 1 to 8 carbon atoms, such as chloromethyl, bromoethyl,

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Bromopropyl, chlorobutyl, iodohexyl or chlorooctyl groups), Nitro groups, aryl groups (such as phenyl or naphthyl groups), Alkylphenyl radicals (in which the alkyl radical as a substituent on the phenyl group is preferably an alkyl radical with 1 to 4 carbon atoms, for example a methyl, ethyl, propyl, butyl or tert-butyl group represents), carry hydroxyl groups, cyano groups, carboxyl groups, amino groups or acetylamino groups.

Specific examples of sulfinic acids and salts thereof are n-octylsulfinic acid, sodium n-octylsulfinate, disodium-2- carboxyethylsulfinate, sodium 2-cyanoethylsulfinate, sodium 2-ethoxycarbonylethylsulfinate, Benzenesulfinic acid dihydrate, p-toluenesulfinic acid, sodium benzene sulfinate, sodium p-toluenesulfinate, Potassium benzenesulf inate, zinc p-toluenesulf inate, Ammonium p-toluenesulfinate, 4-tert-butylbenzenesulfinic acid, p-bromobenzenesulfinic acid, p-chlorobenzenesulfinic acid, 4-acetamido- benzenesulfinic acid, sodium 3 »4-dimethyrbenzenesulfinate, potassium- 3-methylbenzenesulfinate, 4-nitrobenzenesulfinic acid and potassium-2-naphth hyl sulf inate. The sulfinic acids or the sulfinic acid salts can be used either singly or in combination of two or more compounds. Preferably the one used is Amount about 0.0001 to 1 mol, in particular 0.001 to 0.1 mol, in each case per mol of the organic carboxylic acid silver salt component (a).

These sulfinic acids and sulfinic acid salts can be any Time during or after the formation of the organic carboxylic acid silver salt component (a), before or after the formation of the SiI overhalide component (b), or before or after the addition of substances, such as the reducing agent component (c) or the color toner component (d), may be added. The sulfinic acid or sulfinic acid salts are preferably added after formation the organic carboxylic acid silver salt component (a) or during or after the formation of the silver halide component (b).

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An example of the addition of sodium benzene sulfinate to a silver benzotriazole containing silver salt oxidizing agent heat developable material is described in US-P5,3756,829 ". The coordination according to the invention using an organic carboxylic acid silver salt as the silver salt oxidizing agent and a phthalazinone as a color toner, however, is different from this known combination, and accordingly are The object and solution of the invention also differ from the prior art. In the known combination, sodium benzene sulfinate is used used only as a color toner and is therefore unable to prevent heat haze.

Furthermore, it emerges from JA-PA 5020/74 that phthalazinones have no color-toner effect. The invention is based on Surprising observation that the heat haze caused by the color toner effect of phthalazinones in heat developable light-sensitive material, the phthalazinone, organic Contains carboxylic acid silver salts and the other essential components by adding a sulfinic acid or a salt from this disappears completely.

According to the invention, components (a), (b), (c), (d) and (e) are preferably dispersed in a binder component (f) and then applied to a carrier. In this case, all components (a), (b), (c), (d) and (e) can be in the same binder dispersed and applied in a single layer to the support, or components (a) and (b) and the Components (c), (d) and (e), components (a), (b) and (c) and components (d) and (e), components (a), (b) and (e) and components (c) and (d), components (a), (b) and (d) and components (c) and (e), or the components (a), (b), (c) and (d) and component (e) can be dispersed separately in a binder and separately on the carrier are applied so that a multilayer structure is obtained.

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Any "in this" field in general binders used are used. In general, hydrophobic binders are preferred; however, it can also be hydrophilic Binders are used. Preferred binders are those that are transparent or translucent or semi-transparent are. Examples of suitable binders are natural substances such as gelatin, gelatin derivatives, mixtures thereof with Vinyl polymer latices, cellulose derivatives or synthetic polymeric substances. Specific examples are gelatin, with phthalic acid modified gelatine, polyacrylamide, polyvinyl butyral, Cellulose acetate butyrate, cellulose acetate propionate, polymethyl methacrylate, Polyvinylpyrrolidone, polystyrene, ethyl cellulose, polyvinyl chloride, chlorinated rubber, polyisobutylene, Butadiene-styrene copolymers, vinyl chloride-vinyl acetate copolymers, Vinyl acetate-vinyl chloride-maleic acid terpolymers, polyvinyl alcohol, polyvinyl acetate, benzyl cellulose, Cellulose diacetate, cellulose triacetate, cellulose propionate and Cellulose acetate phthalate. These binders can either be used alone or as mixtures of two or more of the foregoing Substances are used. Preferred is a weight ratio from binder component (f) to organic silver salt component component (a) from about 10: 1 to 1:10, in particular 4: 1 to 1: 4 »applied. It is also possible to omit the binder component (f) if the component (a) and / or (c) it is a matter of high molecular weight substances that are also capable of acting as binders.

According to the invention, any desired materials can be used as a carrier Find. Typical examples of suitable supports are films or sheets or plates made of cellulose nitrate, cellulose esters, Polyvinyl acetal, polystyrene, polyethylene terephthalate, Polycarbonate, glass, paper or metal. In the case of paper backings, the paper preferably contains clay or styrene-butadiene rubber.

509838/0 90 9

The binder dispersion is preferably applied to the carrier in an amount of 0.2 to 3 g, in particular 0.3 to 2 g (in each case

calculated on total silver), applied per m carrier. Lies

the amount below about 0.2 g / m 2 can provide sufficient image density not reached v / earth. On the other hand, if the 'amount is above

about 3 g / m, this causes a cost increase without this would be associated with additional advantages.

The heat developable photosensitive material of the invention may also have an antistatic layer or a conductive layer. Furthermore, the heat-developable photosensitive material can contain antihalo substances or antihalo paraffin. Optionally, it contains the heat developable photosensitive Material of the Invention Matting agents such as starch, titanium dioxide, zinc oxide, silicon dioxide or kaolin. Furthermore fluorescent whitening agents such as stilbenes, triazines, oxazoles or coumarins may also be included.

Finally, a polymer topcoat can be applied to the light-sensitive layer as the top-coat, to increase the transmittance of the heat developable photosensitive material and to increase the shelf life of the fresh material (the ability of the light-sensitive material which immediately after the production of the photographic Material to maintain existing properties during storage). Preferably the po- polymer top layer a thickness of about 1 to 20 u.

Preferred examples of those suitable for .the uppermost cover layer Polymers are polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, Polyvinyl butyral, polystyrene, polymethyl methacrylate, polyurethane rubber, xylene resins, benzyl cellulose, Ethyl cellulose, cellulose acetate butyrate, cellulose diacetate, Cellulose triacetate, polyvinylidene chloride, chlorinated polypropylene, polyvinylpyrrolidone, cellulose propionate, polyvinyl formal, Ceirulose acetate phthalate, polycarbonate and

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Cellulose acetate propionate.

Furthermore, the top cover layer preferably contains substances such as kaolin or silicic acid (silicon dioxide), since it is the presence such substances enables the heat developable photosensitive material after imaging with a Writing on ballpoint pen or pencil.

Furthermore, the top polymer cover layer can contain UV absorbers or higher fatty acids.

Furthermore, a phenolic coupler or a color coupler which has an active methylene group can be used together with p-pheny- Lenediamine can be used as a reducing agent in the light-sensitive material, so that color images are formed. This is in the published JA-PA 7782/71.

In addition, it is possible to use the photosensitive material Acids, such as higher fatty acids or benzenesulfonic acid, to be incorporated as a stabilizer, as in JA-PA 37 965/73 and 106 724/73 described.

In addition, stabilizers such as benzotriazole and derivatives thereof or 1-phenyl ~ 5-mercaptotetrazole can be added to the photosensitive material be incorporated.

The heat developable photosensitive layer may be various Additives, such as mercury salts (these are because of their Toxicity not preferred) or N-halogen compounds, such as N-bromosuccinimide, N-bromotetrafluorosuccinimide, N-bromophthalimld, Contain N-bromoacetanilide, N-bromoacetamide or N-chlorosuccinimide, so that heat fog (undesirable fog caused by heating in unexposed areas) is prevented will. This is disclosed in U.S. Patents 3,589,903 and 3,767,394, U.S. Pat US-PA 474 635/74, 434-326 / 74 and 427 612/73, as well as DT-OS 2,427,492.

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Preferably the heat developable photosensitive one contains Material of the invention sensitizer dyes such as cyanine dyes, Merocyanine dyes, rhodacyanine dyes, Styryl or acidic dyes as disclosed in U.S. Patents 3,152,904, 3,457,075 and 3,761,279, and US Pat JA-PA 127 999/72, 14 916/73, 7624/73, 12 587/73, 50 903/73 and 81 550/73. Merocyanine dyes that have a carboxyl group or having a carboxyalkyl group become special preferred because excellent sensitization effects can be achieved. These sensitizer dyes are generally

-6-2

mean in an amount of about 10 to about 10 moles, preferred

-5 -3
wise 10 to 10 hol, each per mole of the organic silver salt component (a) is used.

The heat developable photosensitive layer of the invention, can be produced on the carrier using various coating methods. Examples of suitable procedures are the dip coating, using the coating of slot dies, curtain coating or extrusion topcoat using a funnel as described in US Pat. No. 2,681,294. If necessary, two can also be used or more layers are applied at the same time.

The heat-developable photosensitive material of the invention after exposure to light can be developed by simple heating using various light sources such as xenon lamps, tungsten lamps or mercury lamps. The suitable exposure time depends on the intensity of the lighting, but is generally about 1 to 20 seconds. In general, temperatures of about 80 to 180 ^° C., preferably 110 to 150 ^° C., are heated. Here, higher temperatures correspond to shorter development times and vice versa. Development generally takes about 1 to 60 seconds.

509838/0909

For heating the heat developable en photosensitive. Various heating devices can be used with the materials of the invention. For example, one can use the photosensitive Material in contact with a simple heating plate or heating drum or let it pass through a heated zone. Furthermore, heating the heat developable photosensitive Materials can also be done by means of high-frequency heating or laser beams.

It has been found that the heat developable photosensitive The material of the invention leads to the formation of heat fog only to a very small extent. In addition, the heat developable photosensitive material of the invention easy to handle, since no toxic substances such as mercury compounds, must be present. The images produced are clear and of good quality due to the black tone.

The examples illustrate the invention. Unless otherwise stated, All parts, percentages, proportions and other information are based on weight.

B e i s ρ i el 1

1 liter of an aqueous solution containing 20 g of sodium hydroxide, are made into one with 2 liters of toluene containing 120 g of lauric acid using a high speed stirrer Mixed emulsion. After adding 500 ml of a 0.4 percent aqueous hydrobromic acid solution to this emulsion the mixture is emulsified again. The emulsion thus obtained 500 ml of an aqueous solution containing 85 g of silver nitrate are added. At the same time it comes to Formation of silver bromide and silver laurate. After the toluene phase containing silver laurate and silver bromide from the has separated aqueous phase, the resulting silver salt (silver laurate + silver bromide) 'using a high-speed stirrer in 2.4 kg of a 15 percent solution of

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Polyvinyl butyral dispersed in isopropanol.

200 g of the silver salt polymer dispersion thus obtained are with the components listed below are added to form a heat developable photosensitive coating solution receives. This coating solution is used to coat an art print paper (as a carrier) with a coverage of 0.6 g / m 2 of silver. After drying, a heat developable photosensitive material (A) is obtained.

Component Amount (ml)

2 ·, T'-dichlorofluorescein (sensitizer dye; 0.025 percent solution in methanol) 30 Sodium benzene sulfinate (anti-heat detergent; 1 percent solution in methanol) 4

6-chlorophthalazinone (color toner; 1.8 percent Solution in dimethylformamide) .. 40

p-Ethoxyphenol (reducing agent; 10 percent Solution in acetone) 60

For comparison purposes, a heat developable photosensitive Material (B) prepared in the same way as described above, but with the omission of the sodium benzene sulfinate will. Furthermore, a heat developable photosensitive material (G) is used in the same manner as for photosensitive material (A) described, prepared, but using a 3 percent methanolic solution of phthalazinone is used instead of 6-chlorophthalazinone.

The three photosensitive materials (A), (B) and (C) are behind an original artwork with gradation, using a tungsten light source, exposed and then heated for 10 seconds. In the photosensitive materials (A) and (C) obtained one pictures with black tone with little heat fog. The reflection densities of the unexposed areas are 0.20 and 0.18, respectively. In contrast, the photosensitive Material (B) difficult to see the image obtained because

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there is a high degree of heat fogging, the reflection density is 0.65.

Example 2

A thermally developable photosensitive material (A) is prepared using sodium n-octylsulfinate (2 ml of a 1% methanolic solution) as an antifoggant in place of sodium benzenesulfinate in the thermally developable photosensitive material (A) of Example 1. The obtained thermally developable photosensitive material (A) and the thermally developable photosensitive material (B) of Example 1 are exposed behind an original with gradation using a tungsten light source. The development takes place by heating to 140 ⁰ C for a time of. 15 seconds.

In the case of the photosensitive material (A), no heat fog occurs in the unexposed area (reflection density 0.19) »an image with a black tone is obtained. The photosensitive material (B) has excessive heat fog (reflection density 0.8o) and the image is difficult to see.

Example 5

In the recipe of Example 1, sodium 2-ethoxycarbonyl- ethyl sulfinate instead of sodium benzene sulfinate as an anti-fogging agent used.

When the procedure of Example 1 is repeated, the thermally developable photosensitive material (A) (comprising the 2 — Carboethoxyethylsulfinic acid contains hardly any heat haze (Reflection density 0.20), while the heat developable photosensitive material (B) (which does not contain 2-carboethoxyethylsulfinic acid contains) there is pronounced heat fogging (reflection density 0.65).

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Example 4

3.4 g of behenic acid are dissolved in 100 ml of toluene of 60 G ^0. The solution obtained is then mixed with 100 ml of dilute aqueous nitric acid of pH 2.0 (at 25 ^° C.) using a high-speed stirrer, while the temperature is kept at 20 ^° C. The mixture obtained is then admixed, with stirring, with an aqueous solution which has been obtained by adding an aqueous ammonia solution to 80 ml of an aqueous solution of 1.7 g of silver nitrate (to form a silver ammonium complex salt) and making up to a total volume of 100 ml with water . After 20 minutes of standing the resulting dispersion of microcrystals of (approximately 20 to 30 ⁰ C) SiI-berbehenat at room temperature occurs phase separation into a v / ässrige and an oily phase. After the oily phase has been removed by decantation and washed with water, the silver behenate is separated off by centrifugation. 4 g of spindle-shaped silver behenate crystals with a length of about 1 p are obtained. and a width of about 0.05 U.

After 2.5 g of this silver behenate has been added to 20 ml of a solution of 2 g of polyvinyl butyral in isopropanol, is the resulting mixture treated in a ball mill for 2 hours. The silver salt polymer dispersion obtained is converted into by addition A heat developable photosensitive coating solution was prepared from the components listed below. A polyethylene terephthalate film is made with this coating solution coated with a coverage of 1.5 g silver / m, being a heat developable photosensitive material (A) receives.

Component Amount (ml)

Hydrobromic acid (silver halide-forming Component 2 percent solution in methanol) 1 Tetrachlorotetrabromofluorescein (sensitizer; 0.025% solution in methanol) 5

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8-methylphthalazinone (color toner; 0.8 percent

Solution in ethanol / water (volume ratio

nis 80: 20)) 30

2,2'-methylene-bis- (6-tert-butyl-4-methy1-

phenol) (reaction agent; 20 percent solution

in acetone) 7.5

Sodium p-toluenesulfinate (anti-heat fogging agent; -0, 1 percent Solution in methanol) 5

For comparison purposes, a heat developable photosensitive Material (B), prepared in the same way as described above, except that the sodium p-toluenesulfinate is omitted.

The photosensitive materials (A) and (B) are then exposed according to Example 1 and developed. The reflection die in the unexposed area of the photosensitive material (A) is 0.18, and a good black one is obtained Image, while the photosensitive material (B) leads to considerable heat fogging (reflection density in unexposed area O, 65)> and the image difficult to see is.

example 5

The components listed below are added to 200 g of the silver salt polymer dispersion from Example 1, with a heat developable photosensitive coating solution is obtained. With this coating solution an art printing paper coated with a coverage of 0.6 g silver / m, being a heat developable photosensitive material (A) receives.

Component amount (ml) ,

Sensitizer dye *) (0.025 percent

Solution in 2-methoxyethanol) 30

Potassium benzene sulfinate (anti-heat fogging agent; 1 percent solution in methanol / acetic acid) 10

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4- (1-Naphthyl) -phthalazinon (color toner:

1 percent solution in dimethylformamide) 80

2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane (Reducing agent; 20 percent solution in acetone) 50

*) 3-Allyl-5- (3-ethyl (2-naphthoxazolididene) ethylidene) -1-phenyl-2-thiohydantoin

For the purposes of comparison, a heat-developable medium sensitivity is used. Liches material (B) prepared in the same way, but the potassium benzene sulfinate is omitted.

The photosensitive materials (A) and (B) are then exposed according to Example 1 and developed. Here joins the photosensitive material (A) does not have a heat fog (the reflection density in the unexposed area is 0.18), and you get a good black picture. On the other hand, it becomes more pronounced in the photosensitive material (B) Heat fogging (reflection density 0.70) and the image is difficult to see.

B e i s ρ i e 1 6

After 1.9 g of sodium hydroxide has been dissolved in 200 ml of water, the solution obtained is stirred with 100 ml of toluene containing 12 g of lauric acid using a stirrer to form an emulsion. An aqueous silver nitrate solution (8.5 g of silver nitrate in 50 ml of water) is added to the emulsion obtained for 60 seconds while stirring (800 rpm; 5 min). This leads to the precipitation of silver laurate, which is removed and dispersed in a ball mill together with 30 g of polyvinyl butyral and 200 ml of isopropanol. Here you get a. Silver salt polymer dispersion (solution (A)). After having added 50 g of the silver salt Polymerdisper.sion thus obtained with 6 ml of a 1,4prozentigen solution of N-bromosuccinimide in methanol, the resulting mixture is stirred for 90 minutes at 50 ⁰ C to give a solution (B).

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25 g of the solution (B) are mixed with the components of the formulation I given below. With the mixture obtained
a paper carrier (siyl-coated paper) is coated with a coverage of 0.4 g silver / m, using a heat-
developable photosensitive material (A) is obtained.

Recipe I

Sensitizer dye *) (0.025 percent
Solution in 2-methoxyethanol)

Phthalazinone (color toner; 3 percent solution
in methanol)

p-phenylphenol (reducing agent; 20 percent
Solution in acetone)

Sodium benzenesulfinate (anti-heat fogging agent;
7 percent solution in methanol)

Quantity (ml) 2 4 5 5

*) Sensitizer dye

C ₂ H ₅ CH - CH = p ~ N_ / - I.
N J I. I.
CH ₂ ' Vz O - CH

= CH ₂

For the purpose of comparison, a heat developable photosensitive material (B) is prepared in the same manner as described above except that the sodium benzene sulfinate is omitted. Further, for comparison, the heat developable photosensitive material (C) is used in the same way
produced, but the phthalazinone and the sodium benzene sulfate in the recipe I are omitted.

The photosensitive materials (A), (B) and (C) are
by means of light of 10 lux. sec behind an optical wedge
exposed using a tungsten light source and transmitted through

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Heating to 120 ⁰ C for a period of 40 seconds developed.

In the photosensitive material (A), there is no heat fog (reflection density 0.20), and a black, gradual one is obtained Image. In contrast, the photosensitive material (B) causes considerable heat fog. (reflection density 0.55), and the image is difficult to see. In the photosensitive material (C), although the heat fog is relatively small, it is yellowish brown Image that is difficult to see.

Example 7

50 g of solution (A), prepared in Example 4, are mixed with 6 ml of a 0.6 percent solution of N-bromophthalazinone (silver halide-forming component) in acetone instead of the N-bromosuccinimide used in Example 6. The mixture obtained is ^{heated to 30 °} C. for 90 minutes, the solution (C) being obtained.

25 g of this solution (C) are mixed with the components according to the formulation II given below, whereby a heat developable photosensitive material (A) is obtained.

Formulation II amount (ml)

Dye. *) (0.025 percent solution in

Methanol) 3

Phthalazinone (color toner; 3 percent solution

in methanol) .. 8

Potassium p-toluenesulfinate (anti-heat fogging agentj 0.2 percent solution in methanol) 5

Reducing agent **) (20 percent solution in Acetone) 5

*) Dye: 2 ¹ , T'-dichlorofluorescein **) reducing agent:

5098 38/0909

For comparison purposes, a heat development is shown in photosensitive Material (B) prepared in the same way, except that the potassium p-toluenesulfinate is omitted in formulation II.

The light-sensitive materials (A) and (B) obtained are exposed and developed according to Example 6. The photosensitive one Material (A) has no heat haze (reflection density 0.20), and a black, gradual one is obtained Image. In contrast to this, the photosensitive material (B) leads to pronounced heat fogging (reflection— density 0.55), and the image is difficult to see.

Example 8

3.4 g of silver behenate are dissolved in 100 ml of toluene of 60 ⁰ G; the temperature of the solution is adjusted to 60 ⁰ G. The solution is then mixed with 100 ml of dilute aqueous nitric acid of pH 2.0 (25 ^° C.) while stirring. The mixture thus obtained is then, while maintaining the temperature at 60 ⁰ G,. while stirring with an aqueous solution containing a silver ammonium complex salt, namely an aqueous solution which by adding an aqueous ammonia solution to 80 ml of an aqueous solution containing 1.7 g of silver nitrate, to form the silver ammonium complex salt _i and make up with water to a total volume of 100 ml has been obtained. In this way a dispersion containing microcrystals of silver behenate is obtained. When the dispersion is left to stand for 20 minutes at room temperature, the phases separate into an aqueous one

50 9 8 38/0909

Phase and a toluene phase. After the aqueous phase has been removed, the toluene phase by adding 400 ml Washed fresh water and subsequent decanting. After repeating this process three times, add 400 ml of toluene and the silver behenate is removed by separation using a centrifuge. 4 g of spindle-shaped material are obtained in this way Silver behenate about 1 micron long and about 0.05 microns wide.

2.5 g of this silver behenate are added to 60 ml of an isopropanol added solution containing 6 g of polyvinyl butyral · The obtained The mixture is ground in a ball mill for 1 hour, a polymer dispersion, solution (D) being obtained.

After 50 g of solution (D) have been mixed with 3 ml of N-bromoacetamide (1 percent solution in methanol) and 0.5 ml of N-iodosuccinimide (0.1 percent solution in methanol) (both compounds are silver halide-forming components) has added, the resulting mixture is ^{stirred at 65 °} C. for 90 minutes, the solution (E) being obtained.

The solution (E) is mixed with the components listed below according to recipe III, whereby a heat development bare photosensitive coating composition obtained. This coating compound is used to form a paper carrier with a cover of 0.6 g of silver / m 2 to obtain a heat developable photosensitive material (A).

Formulation III quantity (ml)

Dye (same dye as in Example 4; 0.025 percent solution in 2-methoxyethanol) 2 2,2'-methylenebis (6-tert-butyl-4-methylphenol) (Reducing agent; 25 percent solution in 2-methoxyethanol) 4

Phthalazinon (color toner, 2.5 percent solution

in 2-methoxyethanol) 5

Sodium gumbenzenesulfinate (anti-heat fogging agent; 0.5 percent solution in methanol) 5

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For comparison purposes, it will be a heat developable photosensitive Material (B) prepared in the same way, except that the sodium benzene sulfate in the formulation III is omitted.

The light-sensitive materials (A) and (B) are exposed and developed according to Example 6.

In the case of the photosensitive material (A), there is no heat fog (reflection density 0.19), and a clear, black, gradual image. In contrast to this, the photosensitive material (B) exhibits pronounced heat sink formation (Reflection density 0.60), and the obtained image is difficult to see.

Claims 509838/0909

Claims (11)

Claims Heat developable photosensitive material, characterized by a support and, located thereon, at least a layer comprising (a) a silver salt of an organic carboxylic acid, (b) a photosensitive silver halide or a component that forms a photosensitive silver halide by reacting with the organic carbon acid silver salt (a) capable of forming, (c) a reducing agent, (d) at least one phthalazinone, and (e) at least a sulfinic acid or a sulfinic acid salt. 2. Heat developable material according to claim 1, characterized in that that the silver salt of the organic carboxylic acid (a) is a silver salt of a higher monocarboxylic fatty acid, an aliphatic dicarboxylic acid or an aromatic carboxylic acid. 3 · Heat developable material according to at least one of the claims 1 and 2, characterized in that the silver salt of the organic carboxylic acid (a) is a silver salt of a higher Is monocarboxylic fatty acid. 4. Heat developable material according to at least one of the claims 1 to 3 »characterized in that the light-sensitive silver halide is silver chloride, silver bromide, Silver bromide iodide, silver iodobromochloride, silver bromochloride, silver iodine chloride, silver iodide, or a mixture of the foregoing Is silver halide. 5 »Heat developable material according to at least one of the claims 1 to 4 »characterized in that the component which is a photosensitive silver halide by reaction is able to form with the organic carboxylic acid silver salt (a), an inorganic compound of the general formula MX, in which M is a hydrogen atom, an ammonium group or a 509838/0909 Is metallatoni, X is a halogen atom, and η is the value 1 if M denotes a hydrogen atom or an aramonium group, and η denotes the valence of the metal atom, 'when EI represents a metal atom; containing a halogen Metal complex; an N-halogen compound with a -CONX grouping, in which X is a chlorine, bromine or iodine atom; an H-halobenzotriazole or substituted benzotriazole an onium halide; a halogenated hydrocarbon from the group iodoform, bromofon, carbon tetrabromide and ■ 2-bromo-2-diethylpropane; or a halogen containing compound from the group of triphenylmethyl chloride, triphenylmethyl bromide, 2-bromobutyric acid, 2-bromoethanol and dichlorobenzophenone is. 6. heat developable material according to at least one of claims 1 to 5, characterized in that the reduction ■ means (c) a monohydroxybenzene, dihydroxybiphenyl, di- or Polyhydroxybenzene, naphthol, naphthylamine, aminonaphthol, hydroxybinaphthyl, aminophenyl, p-phenylenediamine, or a Alkylenebisphenol, ascorbic acid or a derivative thereof, or a pyrazolidone. 7. Heat developable material according to at least one of the claims 1 to 6, characterized in that the phthalazinone (d) has the general formula I. - Ri R ₅ (I) R ₃ in which IL, R ₂ , R- and R. each represent a hydrogen atom, _f a halogen atom, an alkyl radical, an alkoxy radical, an Nxtro group, an amino group or a hydroxyl group; Usually a hydrogen atom, halogen atom, an alkyl radical, aryl radical , a benzylidene hydrazino, pyridyl or vinyl group 5098 38/0 909 GOPY is; and at least one of the radicals R ₁ , R _{? , R 1} , R and R 1 - denotes an atom or a group which is not a hydrogen atom. 8. Heat developable material according to at least one of claims 1 to J, characterized in that the sulfinic acid or the sulfinic acid salt (s) has the general formula II R ₆ - SO ₂ X ₁ ■ (II) in which Rg is a monovalent, aliphatic or aromatic radical, and X _{1 is} a monovalent positive ion. 9. Heat developable material according to at least one of the claims 1 to 8, characterized in that the phthalazinone (d) in an amount of about 0.0001 to 2 mol, per mol of the organic carboxylic acid silver salt (a), and the sulfinic acid or the sulfinic acid salt (e) in an amount of about 0.0001 to 1 mole, per mole of the organic carboxylic acid silver salt ■ (a), are present. 10. Use of the heat developable material according to any one of claims 1 to 9 for image formation. . 11. Embodiment according to claim 10, characterized in that the heat developable material according to the imagewise Exposure subjected to development by heating. 509838/0 90 9 copy