JPH11119373A - Heat-developable recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-developable recording material high in sensitivity, Dmax, and contrast and superior preservablity, by incorporating an organic silver salt and a reducing agent and a specified compound. SOLUTION: The heat-developable recording material contains an organic silver salt and a reducing agent and one of the compounds represented by the formula, in which each of R1 -R3 is, independently, H atom or a univalent substituent; Z is an electron withdrawing group or a silyl group; each of R1 and Z, R2 and R3 , R1 and R2 , R3 and Z may combine with each other to form a cyclic structure; at least one of R1 -R3 and Z has a -L1 -(R4 -L2 )n1 -(R5 )n2 -X group; each of R4 and R5 is a divalent aliphatic or aromatic group; each of L1 and L2 is a divalent bonding group; each of n1 and n2 is, independently, 0 or 1; and X is a group for promoting adsorption to a silver salt. When each of R1 -R3 is a univalent group, they are embodied by a halogen atom, and alkyl, alkenyl, alkynyl, aryl, and heterocyclic groups, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat-developable recording material, and more particularly to a heat-developable photosensitive material suitable for printing plate making.

[0002]

2. Description of the Related Art A photothermographic material for forming a photographic image by using a heat development processing method is disclosed, for example, in US Pat. No. 3,152,904.
No. 3,457,075 and D.C. Morgan
And B. "Thermally Processed Silver Systems" by Shely
(Imaging Processes and Materials Neblette 8
Edition, Sturge, V. Walworth
h), A. Shepp, page 2, 1969.

[0003] Such a photothermographic material comprises a reducible silver source (for example, an organic silver salt), a photocatalyst having a catalytic amount (for example, silver halide), a color tone controlling agent for controlling the color tone of silver, and a reducing agent. It is contained in a dispersed state in the matrix. Although the photothermographic material is stable at room temperature, it can be reduced by a redox reaction between a silver source (which functions as an oxidizing agent) and a reducing agent when heated to a high temperature (for example, 80 ° C. or higher) after exposure. Produces silver. This oxidation-reduction reaction is promoted by the catalytic action of the latent image generated by the exposure.
The silver formed by the reaction of the organic silver salt in the exposed areas provides a black image, which contrasts with the unexposed areas, resulting in the formation of an image.

However, at present, such a photothermographic material is often used as a light-sensitive material for micros and a light-sensitive material for medical use, and is only partially used as a light-sensitive material for printing. This is because the obtained image has a low Dmax and soft gradation, so that the image quality of the printing photosensitive material is extremely poor.

On the other hand, in recent years, with the development of lasers and light emitting diodes, scanners and imagesetters having an oscillation wavelength in the range of 600 to 800 nm have become widespread, and the sensitivity, Dmax, and sensitivity of these output devices are high. The development of lumber was strongly desired.

In recent years, in the field of printing, it has been strongly desired to reduce the amount of processing waste liquid from the viewpoint of environmental conservation and space saving. Therefore, there is a need for a technique relating to a photothermographic material for printing, which can be efficiently exposed by a laser imagesetter and can form a black image having high resolution and sharpness. These photothermographic materials can eliminate the use of solution processing chemicals and provide a simpler and more environmentally friendly thermal development system to customers.

US Pat. No. 3,667,958 describes that a photothermographic material using polyhydroxybenzenes in combination with hydroxylamines, reductones or hydrazines has high image quality discrimination and resolution. It has been found that this combination of reducing agents easily causes an increase in fog.

As a method for obtaining a heat-developable recording material having a high Dmax and a high gradation, US Pat.
No. 695, a method of adding a hydrazine derivative to a light-sensitive material. This makes it possible to obtain a heat-developable recording material having a high Dmax and a super-high contrast.
It was found that Dmax, Dmin, the storage stability of the compound, and the like were not all at a satisfactory level.

The use of the hydrazine derivative described in European Patent No. 762196 A1 has improved the high contrast and the storage stability of the compound,
It turns out that it has not yet reached a satisfactory level.

Further, US Pat. No. 5,545,515 or US Pat. No. 5,635,339 shows an example of using acrylonitrile as a co-developer, but the compound used here can obtain a sufficiently satisfactory high contrast. No black spots were observed.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to provide sensitivity,
An object of the present invention is to provide a heat-developable recording material having a high Dmax, a high contrast, and excellent storage stability. Especially, the image quality is good,
An object of the present invention is to provide a photosensitive material for printing plate making of a completely dry process which does not require a wet process.

[0012]

The object of the present invention has been attained by the following items. (1) A heat-developable recording material having at least one image forming layer, comprising an organic silver salt, a reducing agent and a compound represented by the formula (I).

[0013]

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[In the general formula (I), R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a monovalent substituent, and Z represents an electron-withdrawing group or a silyl group. R ₁ and Z, R ₂ and R ₃ , R ₁ and R _2, and R ₃ and Z may be bonded to each other to form a cyclic structure. R ₁ , R ₂ ,
Of R ₃ and Z, at least one -L ₁ - (R ₄ -
L ₂ ) _n1- (R ₅ ) _n2 -X. R ₄ and R ₅ each represent a divalent aliphatic group or an aromatic group, and L ₁ and L ₂ each represent a divalent linking group. n ₁
And n ₂ each independently represent 0 or 1. X represents a group which promotes adsorption to a silver salt. (2) The heat-developable recording material according to the above (1), containing the hydrazine derivative represented by the general formula (H).

[0015]

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[In the general formula (H), R ¹ represents a hydrogen atom or a block group, R ² represents an aliphatic group, an aromatic group or a heterocyclic group, and G ¹ represents —CO—, —COCO
-, - C (= S) -, - SO 2 -, - SO -, - PO
^{(R 3) - (. R} 3 is selected from the same range as the groups defined in R ^1, may be different from R ^1), or an iminomethylene group. A ¹ and A ² each represent a hydrogen atom, an alkylsulfonyl group, an arylsulfonyl group or an acyl group, at least one of which is a hydrogen atom. m1 is 0 or 1, when m1 is 0, R ¹ represents an aliphatic group, an aromatic group or a heterocyclic group. (3) The heat-developable recording material as described in (1) or (2) above, which contains a photosensitive silver halide.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The photothermographic material of the present invention is a photothermographic material having at least one image forming layer, containing an organic silver salt and a reducing agent, and more preferably containing photosensitive silver halide. It is particularly preferable that the material is a printing material having high contrast.

By including the compound represented by the general formula (I) in such a heat-developable recording material,
A sufficiently satisfactory high contrast can be obtained and the storage stability is excellent. In addition, Dmax is high, and high sensitivity is obtained. In order to obtain a high-contrast image, the combined use with a hydrazine derivative is also preferable.

On the other hand, an acrylonitrile compound similar to the general formula (I) cannot achieve both high contrast and storage stability.

Next, the compound represented by formula (I) will be described in detail. In the general formula (I), R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a monovalent substituent. When R ₁ , R ₂ and R ₃ represent a monovalent substituent, examples of the monovalent substituent include, for example, a halogen atom (fluorine atom, chloro atom, bromine atom or iodine atom), an alkyl group (aralkyl group, cycloalkyl group). Alkyl group, active methine group, etc.), alkenyl group, alkynyl group, aryl group, heterocyclic group, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group), acyl group, alkoxycarbonyl group, aryl Oxycarbonyl group, carbamoyl group, carboxy group or salt thereof, sulfonylcarbamoyl group, acylcarbamoyl group, sulfamoylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, thiocarbamoyl group, hydroxy group or salt thereof, alkoxy Group (ethyleneoxy group or propyleneoxy group unit ), An aryloxy group, a heterocyclic oxy group, an acyloxy group (alkoxy or aryloxy) carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an amino group, an (alkyl, aryl, or heterocyclic) amino Group, N-substituted nitrogen-containing heterocyclic group, acylamino group (amide group), sulfonamide group, ureido group,
Thioureido group, imino group, (alkoxy or aryloxy) carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, quaternary ammonium group, oxamoylamino group, (alkyl or aryl) sulfonyluureide Group, acylureido group, acylsulfamoylamino group, nitro group, mercapto group or a salt thereof, (alkyl, aryl or heterocycle) thio group, (alkyl or aryl) sulfonyl group, (alkyl or aryl) sulfinyl group, sulfo group Group or its salt,
Examples include a sulfamoyl group, an acylsulfamoyl group, a sulfonylsulfamoyl group or a salt thereof, a group having a phosphoric amide or a phosphoric ester structure, a silyl group, and a stanyl group.

These monovalent substituents may be further substituted with these substituents.

The electron-withdrawing group represented by Z in the general formula (I) is a substituent whose Hammett's substituent constant σp can take a positive value. Carbonyl group, aryloxycarbonyl group, carbamoyl group, imino group, thiocarbonyl group, sulfonamide group, sulfamoyl group, alkylsulfonyl group,
Arylsulfonyl group, nitro group, halogen atom, perfluoroalkyl group, acyl group, formyl group, phosphoryl group, carboxy group (or salt thereof), sulfo group (or salt thereof), heterocyclic group, alkenyl group, alkynyl group, Examples include an acyloxy group, an acylthio group, a sulfonyloxy group, and an aryl group substituted with these electron-withdrawing groups. Here, the heterocyclic group is a saturated or unsaturated heterocyclic group, for example, a pyridyl group, a quinolyl group, a pyrazinyl group, a benzotriazolyl group, an imidazolyl group, a benzimidazolyl group, a benzoxazolyl group,
Examples thereof include a 1,3-oxazolidine-2,4-dione-3-yl group, a hydantoin-1-yl group, a succinimide group, and a phthalimide group.

The electron-withdrawing group represented by Z in the general formula (I) may further have a substituent, and the substituent includes R ₁ , R ₂ and R in the general formula (I). _{When 3} represents a monovalent substituent, the same substituents as the substituents that may be possessed are mentioned.

In the general formula (I), R ₁ and Z, R ₂ and R ₃ , R
₁ and R ₂ or R ₃ and Z may be bonded to each other to form a cyclic structure. The cyclic structure formed at this time is a saturated carbon ring or a saturated hetero ring.

The electron-withdrawing group represented by Z in the general formula (I) is preferably a group having a total carbon number of 0 to 20,
That is, a cyano group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, an imino group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a nitro group, a perfluoroalkyl group, an acyl group,
A formyl group, a phosphoryl group, an acyloxy group, an acylthio group, or a phenyl group substituted with an arbitrary electron-withdrawing group, and more preferably a cyano group, an alkoxycarbonyl group, a carbamoyl group, an imino group, a sulfamoyl group, or an alkyl group. A sulfonyl group, an arylsulfonyl group, an acyl group, a formyl group, a phosphoryl group, a trifluoromethyl group, or a phenyl group substituted with any electron-withdrawing group, and particularly preferably a cyano group, a formyl group, an acyl group, It is an alkoxycarbonyl group, an imino group or a carbamoyl group, most preferably a cyano group or a formyl group.

The silyl group represented by Z in the general formula (I) is preferably a trimethylsilyl group, t-
Butyldimethylsilyl group, phenyldimethylsilyl group,
A triethylsilyl group, a triisopropylsilyl group, a trimethylsilyldimethylsilyl group and the like.

In the general formula (I), R ₁ , R ₂ and R ₃
Preferably, the monovalent substituent represented by
To 25, specifically, a group having the same meaning as the electron-withdrawing group represented by Z in the above general formula (I), and an alkyl group, a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof) ), An alkoxy group, an aryloxy group, a heterocyclic oxy group, an alkylthio group, an arylthio group, a heterocyclic thio group, an amino group, an alkylamino group, an arylamino group, a heterocyclic amino group, a ureido group, an amide group, or a substituted or Examples include an unsubstituted aryl group.

In the general formula (I), R ₁ is preferably an electron-withdrawing group or an aryl or arylthio group. When R ₁ represents an electron-withdrawing group, preferably, it is a cyano group, a nitro group, an acyl group, a formyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, an imino group, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, or a sulfamoyl group. A trifluoromethyl group, a phosphoryl group, a thiocarbonyl group, a halogen atom, a carboxy group (or a salt thereof), or a saturated or unsaturated heterocyclic group, and further a cyano group, an acyl group, a formyl group, an alkoxycarbonyl group A carbamoyl group, an imino group, a sulfamoyl group, a carboxy group (or a salt thereof), or a saturated or unsaturated heterocyclic group. Particularly preferred are a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, and a saturated or unsaturated heterocyclic group.

When R ₁ represents an aryl group, it is preferably a substituted or unsubstituted phenyl group having 6 to 20 carbon atoms, and examples of the substituent include arbitrary substituents.

In the general formula (I), the monovalent substituent represented by R ₂ and R ₃ is preferably specifically defined as the same as the electron-withdrawing group represented by Z in the general formula (I). Group, alkyl group, hydroxy group (or salt thereof), mercapto group
(Or a salt thereof), an alkoxy group, an aryloxy group,
Heterocyclic oxy group, alkylthio group, arylthio group,
A heterocyclic thio group, an amino group, an alkylamino group, an arylamino group, a heterocyclic amino group, a ureido group, a substituted or unsubstituted phenyl group, or a heterocyclic group;
Particularly preferred are a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, a heterocyclic oxy group, an alkylthio group, a heterocyclic thio group, and a heterocyclic group.

In the general formula (I), Z and R ₁ , or alternatively, R
_It is also preferred that ₂ and R ₃ form a cyclic structure. The cyclic structure formed in this case has a total carbon number of 1 to 25,
It is a saturated carbocycle or a saturated heterocycle.

In the general formula (I), R ₄ and R ₅ represent a divalent aliphatic group or an aromatic group. The divalent aliphatic group is a substituted or unsubstituted, linear, branched, or cyclic alkylene group, alkenylene group, or alkynylene group.
A valent aromatic group is a monocyclic or bicyclic arylene group. R ₄ and R ₅ are preferably an alkylene group or an arylene group, and more preferably R ₄ represents a phenylene group, and R ₅ represents a phenylene group or an alkylene group.

In the general formula (I), the divalent linking groups represented by L ₁ and L ₂ are -O-, -S-, -N ( _RN )-.
( _RN represents a hydrogen atom, a substituted or unsubstituted alkyl group or an aryl group.), -CO-, -C (= S)
_{-, - SO 2 -, -} SO -, - P (O) -, an alkylene group, an arylene group, a single group such as saturated or unsaturated heterocyclic group or a group comprising a combination of these groups. If Shimese the group consisting of a combination where _{specifically, -CON (R N) -,} - SO 2 N (R N) -, - CO
_{O -, - N (R N} ) CON (R N) -, - N (R N) CS
_{N (R N) -, -} N (R N) SO 2 N (R N) -, - SO 2
_{N (R N) CO -,} - SO 2 N (R N) CON (R N) -,
_{-N (R N) COCON (R} N) -, - CON (R N) C
O-, -S-alkylene group -CONH-, -O-alkylene group -CONH-, -O-alkylene group -NHCO
_{-, - N (R N)} N (R N) CONH -, - NHCO- arylene group _{-SO 2 NH -, - OCH 2} -, - OCH 2 C
H ₂ —, —SCH ₂ —, —S-arylene group, —OCH ₂
- arylene _{group, -N (R N) CH 2} -, - OSO 2 -,
And a group such as —SO ₂ —arylene group— and —SSO ₂ —. In addition, these groups may be connected from either side. n ₁ and n ₂ are 0 or 1. In the general formula (I), X represents a group for promoting adsorption to silver halide or an organic silver salt, and preferred examples thereof include a thioamide group,
Examples thereof include a mercapto group and a 5- or 6-membered nitrogen-containing heterocyclic group. As the thioamide adsorption promoting group, the following formula

[0034]

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And may be a part of a ring structure, or preferably an acyclic thioamide group. Useful thioamide adsorption promoting groups are
For example, U.S. Pat. Nos. 4,030,925 and 4,031,
127, 4,080,207, 4,245,0
No. 37, No. 4, 255, 511, No. 4, 266, 01
Nos. 3 and 4,276,364 and Research
Disclosure (Research Disclosure) No. 151
Vol., November 1976, pp. 15162, and 17
6, December 1978, section 17626. Particularly preferred thioamide groups are those represented by the following formula (II).

[0036]

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Wherein one of E ₁ and E ₂ is —N (R ₇ )
- it represents and the other -O -, - S- or -N (R ₈₎ -
Represents R ₆ represents a hydrogen atom, an aliphatic group, or an aromatic group, or combines with E ₁ or E ₂ to form a 5- or 6-membered heterocyclic ring. R ₇ and R ₈ are each a hydrogen atom, an aliphatic group, or an aromatic group.

The thioamide represented by the formula (II) includes thiourea, thiourethane and dithiocarbamic acid ester. Examples of the case where E ₁ or E ₂ and R ₆ are bonded to each other to form a ring include those found as an acidic nucleus of a merocyanine dye, such as 4-thiazoline-2-thione and thiazolidine-2. -Thion, 4-
Oxazoline-2-thione, oxazolidin-2-thione, 2-pyrazolin-5-thione, 4-imidazoline-
2-thione, 2-thiohydantoin, rhodanine, isorhodanine, 2-thio-2,4-oxazolidine, thiobarbituric acid, tetrazoline-5-thione, 1,2,2
4-triazoline-3-thione, 1,3,4-thiadiazoline-2-thione, 1,3,4-oxadiazoline-
2-thione, benzimidazoline-2-thione, benzoxazoline-2-thione and benzothiazoline-2
-Thione and the like, which may be further substituted.

Examples of the mercapto adsorption-promoting group include an aliphatic mercapto group, an aromatic mercapto group, and a heterocyclic mercapto group (a ring-forming thioamide group which is a tautomer when the carbon to which the SH group is bonded is a nitrogen atom). Has already been mentioned). Examples of the aliphatic mercapto group include a mercaptoalkyl group (such as a mercaptoethyl group and a mercaptopropyl group), a mercaptoalkenyl group (such as a mercaptopropenyl group), and a mercaptoalkynyl group (such as a mercaptobutynyl group). Examples of the aromatic mercapto group include, in addition to those described for the ring-forming thioamide group, a 4-mercaptopyridyl group, a 5-mercaptoquinolinyl group, a 6-mercaptobenzothiazolyl group, and the like.

Examples of the 5- or 6-membered nitrogen-containing heterocyclic adsorption promoting group include a 5- or 6-membered nitrogen-containing heterocyclic ring (which may have a condensed ring) comprising a combination of nitrogen, oxygen, sulfur and carbon. And a group derived from Of these, preferred nitrogen-containing heterocycles include benzotriazole, triazole, tetrazole, indazole, benzimidazole, imidazole, benzothiazole, thiazole, benzoxazole, oxazole, thiadiazole, oxadiazole, triazine and the like. These may further have a suitable substituent. More preferably, the nitrogen-containing heterocycle forms imino silver, for example, benzotriazole, triazole, tetrazole and indazole, and most preferably benzotriazole.

Preferred specific examples of the nitrogen-containing heterocyclic group include, for example, benzotriazol-5-yl, 6-chlorobenzotriazol-5-yl, benzotriazol-5-carbonyl, 5-phenyl-1,3,3 4-triazol-2-yl, 4- (5-methyl-1,3,4-
Triazol-2-yl) benzoyl, 1H-tetrazol-5-yl and 3-cyanoindazol-5-yl.

Preferred as X in the general formula (I) is a cyclic thioamide group (ie, a mercapto-substituted nitrogen-containing heterocyclic group, for example, a 2-mercaptothiadiazolyl group, a 3-mercapto-1,2,4-triazolyl group). , 5
-Mercaptotetrazolyl group, 2-mercapto-1,
A 3,4-oxadiazolyl group, a 2-mercaptobenzoxazolyl group, etc.) or a nitrogen-containing heterocyclic group (eg, a benzotriazolyl group, a benzimidazolyl group, an indazolyl group, etc.).

Particularly preferred are a 2-mercaptothiadiazolyl group, a 5-mercaptotetrazolyl group, a 3-mercapto-1,2,4-triazolyl group and a benzotriazolyl group. -Mercapto-
A 1,2,4-triazolyl group and a 5-mercaptotetrazolyl group.

Among the compounds represented by the general formula (I), Z is preferably a cyano group, a formyl group, an acyl group, an alkoxycarbonyl group or a carbamoyl group.
R ₁ represents an electron-withdrawing group or an aryl group, one of R _{2 and} R ₃ is a hydrogen atom and the other is a hydroxy group (or a salt thereof), a mercapto group (or a salt thereof), an alkoxy group, an alkylthio group, X represents a 2-mercaptothiadiazolyl group, a 5-mercaptotetrazolyl group, a 3-mercapto-1,2,4-triazolyl group, a benzotriazolyl group, which represents a heterocyclic oxy group, a heterocyclic thio group, or a heterocyclic group. It is a compound that represents a hydroxyl group. R ₂ or R ₃
Is a hydrogen atom and the other is a hydroxy group (or a salt thereof) or a mercapto group (or a salt thereof), L ₁ represents —O—, —S—, —N (R _N ) —, —CO
-, An alkylene group, an arylene group, a saturated or unsaturated heterocyclic group, and the like, and combinations thereof are preferable. In this case, preferably R ₁ is a group having L _1, n _1, as the value of n ₂ 0 is preferable. One of R _{2 and} R ₃ is a hydrogen atom, and the other is an alkoxy group, an alkylthio group,
When representing a heterocyclic oxy group, a heterocyclic thio group, or a heterocyclic group, L ₁ represents —O—, —S—, —N (R _N ) —, —CO
—, —C (＝ S) —, —SO ₂ —, —P (O) —, an alkylene group, an arylene group, a saturated or unsaturated heterocyclic group, and the like, and combinations thereof are preferable. At this time, L ₁
The group having is preferably R ₁ , R ₂ or R ₃ ,
The value of n ₁ and n ₂ is preferably 0.

The compounds used in the present invention are listed below, but the present invention is not limited thereto.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

[0050]

[Table 5]

[0051]

[Table 6]

[0052]

[Table 7]

The compound represented by formula (I) of the present invention can be synthesized by various known methods. Since the most suitable synthesis method is selected depending on the individual compound, general synthesis methods cannot be mentioned. Among them, some examples of useful routes are shown below.

(Synthesis Example) (Synthesis of Exemplified Compound I-1a) 1-hydroxyethyl-
5-mercaptotetrazole 15 g of acetonitrile 1
After adding 13 ml of triethylamine to the 00 ml solution and cooling with ice, 18 g of phenyl chloroformate was added dropwise and stirred for 1 hour. Ethyl acetate and diluted hydrochloric acid were added to the reaction solution to extract the product, which was then dried and concentrated. To this crude product, 80 ml of toluene, 12 g of ethoxymethylenemalonitrile and 0.5 g of potassium carbonate were added, and the mixture was heated under reflux for 4 hours to remove generated ethanol. After standing to cool, the solvent was distilled off, and the residue was purified by column chromatography to give Exemplified Compound I-1.
6 g of a were obtained. The 1-hydroxyethyl-5-mercaptotetrazole used in the reaction was synthesized by the following method. 200 g of aqueous solution of 20 g of sodium azide
While heating 1 at 80 ° C., 32 g of 2-hydroxyethyl isocyanate was gradually added, and the mixture was further heated and stirred for 2 hours. After allowing to cool, sodium chloride and concentrated hydrochloric acid were added, and the mixture was cooled with ice. The precipitated solid was collected by filtration to obtain 45 g of 1-hydroxyethyl-5-mercaptotetrazole.

(Synthesis of Exemplified Compound I-1b) Exemplified compound I-1b was obtained in exactly the same manner as in the synthesis of Exemplified Compound I-1a except that ethyl ethoxymethylene cyanoacetate was used instead of ethoxymethylenemalononitrile. .

(Synthesis of Exemplified Compound I-31a) (Synthesis of Synthetic Intermediate 1) Cyclohexyl iso- A solution of 7 g of thiocyanate in 30 ml of acetonitrile was added, and the mixture was stirred at 40 ° C. for 3 hours. The reaction solution was cooled with ice, and the precipitated solid was collected by filtration and recrystallized from acetonitrile to obtain 113 g of a synthetic intermediate.

[0057]

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(Synthesis of Exemplified Compound I-31a) A solution of 13 g of the synthetic intermediate 13 in 50 ml of tetrahydrofuran was cooled on ice, 0.2 g of sodium hydride was gradually added, and the mixture was stirred for 15 minutes. To this solution was added 1 g of ethyl formate, and
Stirred for hours. After evaporating the solvent, methanol was added, and the precipitated solid was collected by filtration to give Exemplified Compound I-31a.
2 g were obtained.

The compound represented by the general formula (I) of the present invention may be any of water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone),
It can be used by dissolving in dimethylformamide, dimethylsulfoxide, methylcellosolve and the like.

Further, by a well-known emulsification and dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate or an auxiliary solvent such as ethyl acetate or cyclohexanone is used for dissolution, and An emulsified dispersion can be prepared and used. Alternatively, the powder can be dispersed in water by a ball mill, a colloid mill, or ultrasonic waves by a method known as a solid dispersion method and used.

The compound represented by formula (I) of the present invention may be added to the layer on the image forming layer side of the support, that is, to the image forming layer or any other layer. Alternatively, it is preferably added to a layer adjacent thereto.

The amount of the compound represented by the general formula (I) of the present invention is preferably 1 × 10 ^-6 to 1 mol, more preferably 1 × 10 ^{-5 to} 5 × 10 ^-1 mol, per mol of silver. More preferably 2 ×
Most preferably, it is 10 ^{-5 to} 2 × 10 ^-1 mol. These compounds may be used alone or in combination of two or more.

The heat-developable recording material of the present invention preferably contains a hydrazine derivative represented by the general formula (H).

Next, the hydrazine derivative represented by the general formula (H) and preferably used in the present invention will be described.

[0065]

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In the general formula (H), R ² represents an aliphatic group, an aromatic group, or a heterocyclic group, R ¹ represents a hydrogen atom or a block group, and G ¹ represents —CO—, —COCO—, -C (=
_{S) -, - SO 2 -} , - SO -, - PO (R 3) -. (R 3 is selected from the same range as the groups defined in R ^1, may be different from R ^1), or Represents an iminomethylene group. A ¹ , A ²
Each represents a hydrogen atom, or one represents a hydrogen atom and the other represents a substituted or unsubstituted alkylsulfonyl group, a substituted or unsubstituted arylsulfonyl group, or a substituted or unsubstituted acyl group. m1 is 0 or 1, when m1 is 0, R ¹ represents an aliphatic group, an aromatic group or a heterocyclic group.

In the general formula (H), the aliphatic group represented by R ² is preferably a substituted or unsubstituted, linear, branched or cyclic alkyl, alkenyl or alkynyl group having 1 to 30 carbon atoms. .

In the general formula (H), the aromatic group represented by R ² is a monocyclic or condensed-ring aryl group such as a phenyl group derived from a benzene ring or a naphthalene ring,
And a naphthyl group. The heterocyclic group represented by R ² is a monocyclic or condensed, saturated or unsaturated, aromatic or non-aromatic heterocyclic group, and the heterocyclic ring in these groups is, for example, a pyridine ring , Pyrimidine ring, imidazole ring, pyrazole ring, quinoline ring, isoquinoline ring, benzimidazole ring, thiazole ring,
Examples include a benzothiazole ring, a piperidine ring, a triazine ring, a morpholine ring, a piperidine ring, and a piperazine ring.

Preferred as R ² is an aryl group, an alkyl group, or an aromatic heterocyclic group.

R ² may be substituted. Representative substituents include, for example, a halogen atom (fluorine atom, chloro atom, bromine atom or iodine atom), an alkyl group (aralkyl group, cycloalkyl group, active methine group). Alkenyl group, alkynyl group, aryl group, heterocyclic group, heterocyclic group containing a quaternized nitrogen atom (eg, pyridinio group), acyl group, alkoxycarbonyl group,
Aryloxycarbonyl group, carbamoyl group, carboxy group or a salt thereof, sulfonylcarbamoyl group, acylcarbamoyl group, sulfamoylcarbamoyl group, carbazoyl group, oxalyl group, oxamoyl group, cyano group, thiocarbamoyl group, hydroxy group, alkoxy group ( (Including a group repeatedly containing an ethyleneoxy group or a propyleneoxy group unit), an aryloxy group, a heterocyclic oxy group, an acyloxy group, an (alkoxy or aryloxy) carbonyloxy group, a carbamoyloxy group, a sulfonyloxy group, an amino group, (Alkyl, aryl, or heterocyclic) amino group, N-substituted nitrogen-containing heterocyclic group, acylamino group, sulfonamide group, ureido group, thioureido group, imide group, (alkoxy or aryloxy Carbonylamino group, sulfamoylamino group, semicarbazide group, thiosemicarbazide group, hydrazino group, quaternary ammonio group, oxamoylamino group, (alkyl or aryl) sulfonyluureido group, acylureido group, acylsulfamoylamino group, A nitro group, a mercapto group, an (alkyl, aryl, or heterocyclic) thio group, an (alkyl or aryl) sulfonyl group, an (alkyl or aryl) sulfinyl group, a sulfo group or a salt thereof, a sulfamoyl group,
Examples include an acylsulfamoyl group, a sulfonylsulfamoyl group or a salt thereof, a group having a phosphoric acid amide or a phosphoric ester structure, a silyl group, a stanyl group, and the like.

These substituents may be further substituted with these substituents.

[0072] Preferred examples of the substituent which may be R ² optionally has, when R ² represents an aromatic group or a heterocyclic group, (including an active methylene group) alkyl group, an aralkyl group, a heterocyclic group, Substituted amino group, acylamino group, sulfonamide group, ureido group, sulfamoylamino group,
Imide group, thioureido group, phosphoric amide group, hydroxy group, alkoxy group, aryloxy group, acyloxy group, acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, carboxy group (including its salt), (alkyl , Aryl, or heterocycle)
Examples thereof include a thio group, a sulfo group (including a salt thereof), a sulfamoyl group, a halogen atom, a cyano group, and a nitro group.

When R ² represents an aliphatic group, an alkyl group, an aryl group, a heterocyclic group, an amino group, an acylamino group, a sulfonamide group, a ureido group, a sulfamoylamino group, an imide group, a thioureido group, Phosphoric acid amide group, hydroxy group, alkoxy group, aryloxy group,
Acyloxy group, acyl group, alkoxycarbonyl group,
Aryloxycarbonyl group, carbamoyl group, carboxy group (including its salt), (alkyl, aryl, or heterocycle) thio group, sulfo group (including its salt), sulfamoyl group, halogen atom, cyano group, nitro group, etc. Is preferred.

In the general formula (H), R ¹ represents a hydrogen atom or a blocking group, and the blocking group is specifically an aliphatic group (specifically, an alkyl group, an alkenyl group, an alkynyl group), an aromatic group or an aromatic group. Group (monocyclic or condensed-ring aryl group), heterocyclic group, alkoxy group, aryloxy group,
Represents an amino group or a hydrazino group.

The alkyl group represented by R ¹ is preferably a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, for example, methyl, ethyl, trifluoromethyl, difluoromethyl, 2-carboxytetra. Fluoroethyl group, pyridiniomethyl group, difluoromethoxymethyl group, difluorocarboxymethyl group, 3-hydroxypropyl group, hydroxymethyl group, 3-methanesulfonamidopropyl group, benzenesulfonamidomethyl group, trifluoroacetylmethyl group, dimethylaminomethyl Group, phenylsulfonylmethyl group, o-hydroxybenzyl group, methoxymethyl group, phenoxymethyl group, 4-ethylphenoxymethyl group, phenylthiomethyl group, t-butyl group, dicyanomethyl group, diphenylmethyl group, triphenyl Examples include a methyl group, a methoxycarbonyldiphenylmethyl group, a cyanodiphenylmethyl group, and a methylthiodiphenylmethyl group. The alkenyl group is preferably an alkenyl group having 1 to 10 carbon atoms, for example, a vinyl group, a 2-ethoxycarbonylvinyl group, a 2-trifluoro-2-methoxycarbonylvinyl group, a 2,2-dicyanovinyl group, a 2-cyano group -2-methoxycarbonylvinyl group and the like. The alkynyl group is preferably an alkynyl group having 1 to 10 carbon atoms, such as an ethynyl group and a 2-methoxycarbonylethynyl group. As the aryl group, a monocyclic or condensed-ring aryl group is preferable, and an aryl group containing a benzene ring is particularly preferable. For example, phenyl, perfluorophenyl, 3,5-dichlorophenyl, 2-methanesulfonamidophenyl, 2-carbamoylphenyl, 4,5-dicyanophenyl, 2-hydroxymethylphenyl, 2,6-dichloro -4-cyanophenyl group, 2-chloro-5-octylsulfamoylphenyl group and the like.

The heterocyclic group is preferably a 5- to 6-membered, saturated or unsaturated, monocyclic or condensed heterocyclic group containing at least one of nitrogen, oxygen and sulfur atoms. Morpholino group, piperidino group (N-substituted), imidazolyl group, indazolyl group (4-
Nitroindazolyl group, pyrazolyl group, triazolyl group, benzimidazolyl group, tetrazolyl group, pyridyl group, pyridinio group (N-methyl-3-pyridinio group, etc.), quinolinio group, quinolyl group, hydantoyl group, imidazolidinyl group, etc. is there.

The alkoxy group is preferably an alkoxy group having 1 to 8 carbon atoms, for example, methoxy, 2-hydroxyethoxy, benzyloxy, t-butoxy and the like. As the aryloxy group, a substituted or unsubstituted phenoxy group is preferable, and as the amino group, an unsubstituted amino group, and an alkylamino group having 1 to 10 carbon atoms,
An arylamino group or a saturated or unsaturated heterocyclic amino group (including a nitrogen-containing heterocyclic amino group containing a quaternized nitrogen atom) is preferred. Examples of the amino group include 2,2,6,6-tetramethylpiperidin-4-ylamino group, propylamino group, 2-hydroxyethylamino group, anilino group, o-hydroxyanilino group, 5
-Benzotriazolylamino group, N-benzyl-3-pyridinioamino group and the like. As the hydrazino group, a substituted or unsubstituted hydrazino group, or a substituted or unsubstituted phenylhydrazino group (such as a 4-benzenesulfonamidophenylhydrazino group) is particularly preferred.

The group represented by R ¹ may be substituted, and examples of the substituent include those exemplified as the substituent of R ² .

In the general formula (H), R ¹ cleaves the G ¹ -R ¹ moiety from the residual molecule and causes a cyclization reaction to form a cyclic structure containing atoms of the -G ¹ -R ¹ moiety. For example, Japanese Patent Application Laid-Open
No. 29751 and the like.

The hydrazine derivative represented by the formula (H) may have a built-in adsorptive group that adsorbs to silver halide. Such adsorbing groups include alkylthio, arylthio, thiourea, thioamide,
U.S. Pat. Nos. 4,385,108 and 4,459,347, JP-A-59-195233, JP-A-59-200231, JP-A-59-201045 and JP-A-59-201045, such as mercapto heterocyclic groups and triazole groups. 201046, 5
Nos. 9-201047, 59-201048, 59
-201049, JP-A-61-170733, and 6
1-270744, 62-948, 63-23
No. 4244, No. 63-234245, No. 63-234
No. 246. These adsorbing groups to silver halide may be precursors. As such a precursor, JP-A-2-285
No. 344.

R ¹ or R ^{2 in} the general formula (H) may have a ballast group or polymer commonly used in immobile photographic additives such as couplers incorporated therein. The ballast group is a group having a carbon number of 8 or more and relatively inactive to photographic properties, such as an alkyl group, an aralkyl group, an alkoxy group, a phenyl group, an alkylphenyl group, a phenoxy group, and an alkylphenoxy group. You can choose from. Examples of the polymer include those described in JP-A-1-100530.

R ¹ or R ² in the general formula (H) may contain a plurality of hydrazino groups as substituents. At this time, the compound represented by the general formula (H) is a polymer having a hydrazino group. Represents, for example, JP-A-64-86134
No., JP-A-4-16938, JP-A-5-97091, WO95-
No. 32452, WO95-32453, Japanese Patent Application No. 7-3511
No. 32, Japanese Patent Application No. 7-351269, Japanese Patent Application No. 7-351168, Japanese Patent Application No. 7-351
Compounds described in Japanese Patent Application No. 351287 and Japanese Patent Application No. 7-351279 are exemplified.

R ¹ or R ^{2 in} the general formula (H) represents a cationic group (specifically, a group containing a quaternary ammonium group, or a nitrogen-containing hetero atom containing a quaternized nitrogen atom). Ring group), a group containing a repeating unit of an ethyleneoxy group or a propyleneoxy group, a (alkyl, aryl, or heterocyclic) thio group, or a dissociable group (carboxy group, sulfo group, acylsulfa Moyl group, carbamoylsulfamoyl group, etc.). Examples of those groups include, for example, JP-A-7-234471 and JP-A-5-333466.
JP-A-6-19032, JP-A-6-19031
JP-A-5-45761, U.S. Pat. No. 4,994,365.
No. 4,988,604, JP-A-3-25924.
No. 0, JP-A-7-5610, JP-A-7-244348
And the compounds described in German Patent No. 4006032.

In the general formula (H), A ¹ and A ^{2 each} represent a hydrogen atom, an alkyl or arylsulfonyl group having 20 or less carbon atoms (preferably a phenylsulfonyl group or a Hammett substituent having a sum of -0.5 or more. Phenylsulfonyl group), an acyl group having 20 or less carbon atoms (preferably a benzoyl group, or a benzoyl group substituted so that the sum of Hammett's substituent constants becomes -0.5 or more, or A chain, branched or cyclic substituted or unsubstituted aliphatic acyl group (here, examples of the substituent include a halogen atom, an ether group, a sulfonamide group, a carbonamide group, a hydroxy group, a carboxy group, a sulfo group, etc. )).

A ¹ and A ² are most preferably hydrogen atoms.

Next, the preferred range of the hydrazine derivative represented by the general formula (H) of the present invention will be described.

In the general formula (H), R ² is a phenyl group,
An alkyl group having 1 to 3 carbon atoms or an aromatic heterocyclic group is preferred.

When R ² represents a phenyl group or an aromatic heterocyclic group, preferred substituents are a nitro group, a cyano group, an alkoxy group, an alkyl group, an acylamino group,
Ureido group, sulfonamide group, thioureido group, carbamoyl group, sulfamoyl group, sulfonyl group, carboxy group (or salt thereof), sulfo group (or salt thereof),
Examples thereof include an alkoxycarbonyl group and a chloro atom.

[0089] When R ² represents a substituted alkyl group having 1 to 3 carbon atoms, R ² is more preferably a substituted methyl group, more preferably a disubstituted methyl group or trisubstituted methyl group, as a substituent Are specifically a methyl group, a phenyl group, a cyano group, an (alkyl, aryl or heterocycle) thio group, an alkoxy group, an aryloxy group, a chloro atom, a heterocyclic group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl A group, a sulfamoyl group, an amino group, an acylamino group, or a sulfonamide group is preferred, and a substituted or unsubstituted phenyl group is particularly preferred.

When R ² represents a substituted methyl group, more preferred examples are t-butyl group, dicyanomethyl group, dicyanophenylmethyl group, triphenylmethyl group (trityl group), diphenylmethyl group, methoxycarbonyldiphenyl Examples include a methyl group, a cyanodiphenylmethyl group, a methylthiodiphenylmethyl group, a cyclopropyldiphenylmethyl group, and among them, a trityl group is most preferred.

When R ² represents an aromatic heterocyclic group, more preferably, the hetero ring in R ² is a pyridine ring, quinoline ring, pyrimidine ring, triazine ring, benzothiazole ring, benzimidazole ring, thiophene ring or the like. It is time to represent.

In the general formula (1), R ² is most preferably a substituted or unsubstituted phenyl group.

[0093] While in m1 general formula (H) represents 1 or 0, when m1 is 0, R ¹ represents an aliphatic group, an aromatic group or a heterocyclic group. When m1 is 0, R ¹ is particularly preferably a phenyl group, a substituted alkyl group having 1 to 3 carbon atoms, or an alkenyl group. The preferred range is the same as the preferred range of R ² described above. When R ¹ is an alkenyl group, preferably R ¹ is a vinyl group, and is a substituent selected from the following substituents: a cyano group, an acyl group, an alkoxycarbonyl group, a nitro group, a trifluoromethyl group, a carbamoyl group and the like. Group is 1
A vinyl group having two or two groups is particularly preferred. Specific examples include a 2,2-dicyanovinyl group, a 2-cyano-2-methoxycarbonylvinyl group, and a 2-acetyl-2-ethoxycarbonylvinyl group.

M1 is preferably 1.

Preferred among the groups represented by R ¹ are those in which R ² represents a phenyl group or an aromatic heterocyclic group;
And when G ¹ is —CO—, a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group, more preferably a hydrogen atom, an alkyl group, or an aryl group, and most preferably Is a hydrogen atom or an alkyl group. Here, when R ¹ represents an alkyl group, the substituent is a halogen atom, an alkoxy group,
Aryloxy group, alkylthio group, arylthio group,
Particularly preferred are a hydroxy group, a sulfonamide group, an amino group, an acylamino group, and a carboxy group.

R ² represents a substituted methyl group, and G ¹ represents-
In the case of CO-, R ¹ is preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an amino group (unsubstituted amino group, alkylamino group, arylamino group, heterocyclic amino group). And more preferably a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an alkylamino group, an arylamino group, or a heterocyclic amino group. When G ¹ is —COCO—, R
Regardless of ² , R ¹ is an alkoxy group, an aryloxy group,
An amino group is preferred, and a substituted amino group, specifically an alkylamino group, an arylamino group, or a saturated or unsaturated heterocyclic amino group is particularly preferred.

When G ¹ is —SO ₂ —, R ¹ is preferably an alkyl group, an aryl group or a substituted amino group regardless of R ² .

In the general formula (H), G ¹ is preferably-
CO- or -COCO-, particularly preferably -C
O-.

Next, specific examples of the compound represented by formula (H) are shown below. However, the present invention is not limited to the following compounds.

[0100]

[Table 8]

[0101]

[Table 9]

[0102]

[Table 10]

[0103]

[Table 11]

[0104]

[Table 12]

[0105]

[Table 13]

[0106]

[Table 14]

[0107]

[Table 15]

[0108]

[Table 16]

[0109]

[Table 17]

[0110]

[Table 18]

[0111]

[Table 19]

[0112]

[Table 20]

[0113]

[Table 21]

[0114]

[Table 22]

[0115]

[Table 23]

[0116]

[Table 24]

[0117]

[Table 25]

[0118]

[Table 26]

[0119]

[Table 27]

[0120]

[Table 28]

[0121]

[Table 29]

The hydrazine derivative used in the present invention is
One type may be used alone, or two or more types may be used in combination. Also,
In addition to the above, the following hydrazine derivatives are also preferably used. (In some cases, they can be used in combination.) The hydrazine derivative used in the present invention can also be synthesized by various methods described in the following patents.

(Formula 1) described in JP-B-6-77138
And specifically the compounds described on pages 3 and 4 of the same publication. A compound represented by the general formula (I) described in JP-B-6-93082, specifically, pages 8 to 1 of the publication
Compounds 1 to 38 on page 8. JP-A-6-23049
A compound represented by the general formula (4), the general formula (5) or the general formula (6) described in No. 7;
Compounds 4-1 to 4-10 described on page 26, compounds 5-1 to 5-42 described on pages 28 to 36, and 39
6-1 to 6-7. Compounds represented by general formula (H) and general formula (2) described in JP-A-6-289520.
Compounds 1-1) to 1-17) and 2-
1). Compounds represented by (Chemical Formula 2) and (Chemical Formula 3) described in JP-A-6-313936, specifically, compounds described on pages 6 to 19 of the same. Compounds represented by (Chemical Formula 1) described in JP-A-6-313951, specifically, compounds described on pages 3 to 5 of the same. Compounds represented by formula (I) described in JP-A-7-5610, specifically, compounds I-1 to I-38 described on pages 5 to 10 of the same. Compounds represented by the general formula (II) described in JP-A-7-77783, specifically, compounds II-1 to II-102 described on pages 10 to 27 of the same. Compounds represented by general formula (H) and general formula (Ha) described in JP-A-7-104426, specifically, compound H described on pages 8 to 15 of the same publication
-1 to H-44. EP-713131A is a compound characterized by having an anionic group or a nonionic group forming an intramolecular hydrogen bond with a hydrogen atom of hydrazine in the vicinity of a hydrazine group. Compounds represented by Formula (B), Formula (C), Formula (D), Formula (E), or Formula (F), specifically, Compounds N-1 to N-1 described in the same specification. N-30. EP-71
No. 3131A, represented by the general formula (H), specifically, compounds D-1 to D-5 described in the same specification
5.

Further, “Known Techniques (1 to
207) ”(published by Aztec) on pages 25 to 34. Compounds D-2 and D-39 of JP-A-62-86354 (pages 6 to 7).

The hydrazine-based nucleating agent of the present invention may be water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, methyl It can be used by dissolving it in cellosolve or the like.

Further, by a well-known emulsification and dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone is used for dissolution, and An emulsified dispersion can be prepared and used. Alternatively, a powder of a hydrazine derivative can be dispersed in a suitable solvent such as water by a ball mill, a colloid mill, or ultrasonic waves by a method known as a solid dispersion method, and used.

The hydrazine nucleating agent of the present invention may be added to the layer on the image forming layer side with respect to the support, that is, to the image forming layer or any other layer. It is preferred to add.

The amount of the nucleating agent of the present invention is preferably 1 × 10 ^-6 to 1 mol per mol of silver halide, and more preferably 1 × 10 ^-6 to 1 mol.
^{-5 to} 5 × 10 ^-1 mol is more preferred, and 2 × 10 ^-5 to 2 ×
10 ^-1 mol is most preferred.

The organic silver salt which can be used in the present invention includes:
Relatively stable to light, but forms a silver image when heated to 80 ° C. or higher in the presence of an exposed photocatalyst (such as a latent image of photosensitive silver halide) and a reducing agent It is a silver salt. The organic silver salt can be any organic substance including a source capable of reducing silver ions. Silver salts of organic acids, in particular silver salts of long-chain fatty carboxylic acids (with 10 to 30, preferably 15 to 28 carbon atoms) are preferred. Complexes of organic or inorganic silver salts wherein the ligand has a complex stability constant in the range of 4.0 to 10.0 are also preferred. The silver donor is preferably present in about 5-70 of the imaging layer.
% By weight. Preferred organic silver salts include silver salts of organic compounds having a carboxyl group. Examples of these include, but are not limited to, silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of the aliphatic carboxylic acid silver salt include silver behenate, silver arachidate, silver stearate, silver oleate,
Silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver linoleate, silver butyrate and silver camphorate, and mixtures thereof.

A silver salt of a compound containing a mercapto group or a thione group and derivatives thereof can also be used.
Preferred examples of these compounds include 3-mercapto-4
-Phenyl-1,2,4-triazole silver salt, 2-mercaptobenzimidazole silver salt, 2-mercapto-5-aminothiadiazole silver salt, 2- (ethylglycolamide) benzothiazole silver salt, S- Silver salts of thioglycolic acid such as silver salts of alkylthioglycolic acid (where the alkyl group has 12 to 22 carbon atoms), silver salts of dithiocarboxylic acids such as silver salts of dithioacetic acid, silver salts of thioamides, 5 -Carboxyl-1-methyl-2-phenyl-4-thiopyridine silver salt, mercaptotriazine silver salt, 2-mercaptobenzoxazole silver salt, silver salts described in U.S. Pat.No.4,123,274, for example, 3-amino-5 Silver salts of 1,2,4-mercaptothiazole derivatives such as -benzylthio-1,2,4-thiazole silver salt, 3- (3-carboxyethyl) -4- described in U.S. Pat.No. 3,301,678
Includes silver salts of thione compounds such as silver salt of methyl-4-thiazoline-2-thione. Furthermore, compounds containing an imino group can also be used. Preferred examples of these compounds include silver salts of benzotriazole and derivatives thereof,
For example, silver salts of benzotriazole such as silver methylbenzotriazole, silver salts of halogen-substituted benzotriazole such as silver 5-chlorobenzotriazole, U.S. Pat.
0,709 1,2,4-triazole or 1-H-
Includes silver salts of tetrazole, silver salts of imidazole and imidazole derivatives, and the like. For example, U.S. Pat.
Various silver acetylide compounds as described in No. 1 and 4,775,613 can also be used.

The shape of the organic silver salt that can be used in the present invention is not particularly limited, but a needle crystal having a short axis and a long axis is preferable. In the present invention, the minor axis is 0.01 μm or more and 0.2 μm or more.
0 μm or less, major axis of 0.10 μm or more and 5.0 μm or less, minor axis of 0.01 μm or more and 0.15 μm or less, and major axis of 0.10 μm or more and 4.0 μm or less are more preferred. The particle size distribution of the organic silver salt is preferably monodispersed. Monodisperse and the minor axis, the percentage of the value obtained by dividing the standard deviation of the length of each major axis by each minor axis, major axis is preferably 100% or less, more preferably 80% or less,
More preferably, it is 50% or less. The shape of the organic silver salt can be measured from a transmission electron microscope image of the organic silver salt dispersion. As another method of measuring the monodispersity, there is a method of determining the standard deviation of the volume-weighted average diameter of the organic silver salt, the percentage of the value divided by the volume-weighted average diameter (coefficient of variation) is preferably 100% or less, more Preferably 80% or less,
More preferably, it is 50% or less. As a measuring method, for example, the particle size (volume weighted average diameter) obtained by irradiating a laser beam to an organic silver salt dispersed in a liquid and obtaining an autocorrelation function with respect to a time change of fluctuation of the scattered light is obtained. Can be.

The organic silver salt that can be used in the present invention includes:
Preferably, desalting can be performed. The method for desalting is not particularly limited, and a known method can be used. However, a known filtration method such as centrifugal filtration, suction filtration, ultrafiltration, and floc forming water washing by a coagulation method can be preferably used. .

The organic silver salt which can be used in the present invention includes:
In order to obtain fine particles with small particle size and no aggregation,
It may be used as a solid fine particle dispersion using a dispersant. The method of dispersing the organic silver salt into solid fine particles is carried out by using a known fine means (for example, a ball mill, a vibrating ball mill, a planetary ball mill, a sand mill, a colloid mill, a jet mill, a roller mill) in the presence of a dispersing agent. Can be dispersed.

When the organic silver salt is formed into solid fine particles using a dispersant, for example, polyacrylic acid, a copolymer of acrylic acid, a maleic acid copolymer, a maleic acid monoester copolymer, and acryloylmethyl Synthetic anionic polymers such as propanesulfonic acid copolymers, semi-synthetic anionic polymers such as carboxymethyl starch and carboxymethyl cellulose, anionic polymers such as alginic acid and pectic acid, and JP-A-52-92716, WO88 / 04794, etc. Anionic surfactant described, the compound described in Japanese Patent Application No. 7-350753, or known anionic, nonionic,
Cationic surfactants and other known polymers such as polyvinyl alcohol, polyvinylpyrrolidone, carboxymethylcellulose, hydroxypropylcellulose, and hydroxypropylmethylcellulose, or naturally occurring polymer compounds such as gelatin can be appropriately selected and used. .

It is a general method that the dispersing aid is mixed with the organic silver salt powder or the organic silver salt in a wet cake state before dispersion, and then sent as a slurry to the dispersing machine. Heat treatment or treatment with a solvent may be performed in the combined state to form an organic silver salt powder or a wet cake. The pH may be controlled by a suitable pH adjuster before, during or after dispersion.

In addition to mechanical dispersion, the particles may be coarsely dispersed in a solvent by controlling the pH, and then finely divided by changing the pH in the presence of a dispersing aid. At this time, an organic solvent may be used as a solvent used for the coarse dispersion, and the organic solvent is usually removed after the completion of the fine particle formation.

The prepared dispersion is stored with stirring for the purpose of suppressing sedimentation of fine particles during storage, or stored in a highly viscous state (for example, in a jelly state using gelatin) with a hydrophilic colloid. You can also do.
Further, a preservative can be added for the purpose of preventing the propagation of various bacteria during storage.

Although the organic silver salt of the present invention can be used in a desired amount, the silver amount is preferably 0.1 to 5 g / m ² , more preferably 1 to 3 g, expressed in terms of the coating amount per m ^{2 of the} heat-developable recording material. /
a m ^2.

When the heat-developable recording material of the present invention is used as a photothermal recording material, photosensitive silver halide can be further used. In this case, a method for forming a photosensitive silver halide is well known in the art, and for example, a method described in Research Disclosure No. 17029, June 1978, and U.S. Patent No. 3,700,458 can be used. . Specific methods that can be used in the present invention include a method of converting a part of the silver of the organic silver salt to a photosensitive silver halide by adding a halogen-containing compound to the prepared organic silver salt, gelatin. Alternatively, a method of preparing a photosensitive silver halide grain by adding a silver supply compound and a halogen supply compound to another polymer solution and mixing the resultant with an organic silver salt can be used. In the present invention, the latter method can be preferably used. The particle size of the photosensitive silver halide is preferably small for the purpose of suppressing the white turbidity after image formation to be low.
20 μm or less, more preferably 0.01 μm or more and 0.16 μm or less,
More preferably, the thickness is 0.02 μm or more and 0.14 μm or less. Here, the grain size means the length of the edge of the silver halide grain when the silver halide grain is a cubic or octahedral so-called normal crystal. In the case where the silver halide grains are tabular grains, the diameter refers to a diameter when converted into a circular image having the same area as the projected area of the main surface. In the case of other than normal crystals, for example, in the case of spherical grains, rod-shaped grains, etc., it refers to the diameter of a sphere equivalent to the volume of silver halide grains.

The shape of the silver halide grains is cubic,
Octahedral, tabular particles, spherical particles, rod-like particles, potato-like particles and the like can be mentioned. In the present invention, cubic particles and tabular particles are particularly preferable. When tabular silver halide grains are used, the average aspect ratio is preferably 100: 1 to 2: 1, more preferably 50: 1 to 3: 1. Further, grains having rounded corners of silver halide grains can also be preferably used. The surface index (mirror index) of the outer surface of the photosensitive silver halide grain is not particularly limited, but the spectral sensitization efficiency when the spectral sensitizing dye is adsorbed is high.
The proportion occupied by the {100} plane is preferably high. The ratio is preferably 50% or more, more preferably 65% or more,
80% or more is more preferable. The Miller index ratio of {100} plane was determined by T. Tani; J. Imaging Sci., 29, 165 (1985) using the dependence of adsorption of sensitizing dyes on {111} and {100} planes. It can be determined by the method described. The halogen composition of the photosensitive silver halide is not particularly limited, and may be any of silver chloride, silver chlorobromide, silver bromide, silver iodobromide, silver iodochlorobromide, and silver iodide. The distribution of the halogen composition in the grains may be uniform, the halogen composition may be changed stepwise, or may be changed continuously, but as a preferable example, the silver iodide content inside the grains is High silver iodobromide grains can be used. Preferably, silver halide grains having a core / shell structure can be used. The structure is preferably 2
Core / shell particles having a ５5-fold structure, more preferably a 2- to 4-fold structure, can be used.

The photosensitive silver halide grains usable in the present invention include rhodium, rhenium, ruthenium, osmium,
It is preferable to contain at least one complex of a metal selected from iridium, cobalt, mercury and iron. One type of these metal complexes may be used, or two or more types of complexes of the same metal and different metals may be used in combination. The preferred content is in the range of 1 nmol to 10 mmol per 1 mol of silver, more preferably 10 nmol to 100 µmol. As a specific structure of the metal complex, a metal complex having a structure described in JP-A-7-225449 or the like can be used.
As the compound of cobalt and iron, a hexacyano metal complex can be preferably used. Specific examples include ferricyanate ion, ferrocyanate ion, hexacyanocobaltate ion, and the like, but are not limited thereto. The metal complex in the silver halide may be contained uniformly, may be contained in the core portion at a high concentration, or may be contained in the shell portion at a high concentration, and there is no particular limitation.

The photosensitive silver halide grains can be desalted by washing with a method known in the art, such as a noodle method or flocculation method, but in the present invention, it may or may not be desalted. .

The photosensitive silver halide grains usable in the present invention are preferably chemically sensitized. As a preferred chemical sensitization method, a sulfur sensitization method, a selenium sensitization method, and a tellurium sensitization method are well known in the art. Further, a noble metal sensitization method or a reduction sensitization method of a gold compound, platinum, palladium, an iridium compound or the like can be used. As the compound preferably used in the sulfur sensitization method, the selenium sensitization method, and the tellurium sensitization method, known compounds can be used, and the compounds described in JP-A-7-128768 can be used. Examples of tellurium sensitizers include diacyl tellurides, bis (oxycarbonyl) tellurides, bis (carbamoyl) tellurides, diacyl tellurides, bis (oxycarbonyl) ditellurides, bis (carbamoyl) ditellurides, P = Te Compounds having a bond, tellurocarboxylates, Te-organyltellurocarboxylates, di (poly) tellurides, tellurides, tellurols, telluroacetals, tellurosulfonates, P-Te
Compounds having a bond, Te-containing heterocycles, tellurocarbonyl compounds, inorganic tellurium compounds, colloidal tellurium, and the like can be used. Compounds preferably used for the noble metal sensitization method include, for example, chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide, gold selenide, or U.S. Pat.
Compounds described in 18,061 and the like can be preferably used. As specific compounds of the reduction sensitization method, in addition to ascorbic acid and thiourea dioxide, for example, stannous chloride, aminoiminomethanesulfinic acid, hydrazine derivatives, borane compounds, silane compounds, polyamine compounds and the like can be used. . Reduction sensitization can be achieved by ripening the emulsion while maintaining the pH of the emulsion at 7 or more or the pAg at 8.3 or less. Further, reduction sensitization can be achieved by introducing a single addition portion of silver ion during grain formation.

When a photosensitive silver halide is used in the present invention, the amount of the photosensitive silver halide to be used is preferably from 0.01 mol to 0.5 mol, and more preferably from 0.02 mol to 1 mol of the organic silver salt. It is more preferably at least 0.3 mol and not more than 0.03 mol, particularly preferably at least 0.03 mol and not more than 0.25 mol. Regarding the mixing method and the mixing conditions of the separately prepared photosensitive silver halide and organic silver salt, the prepared silver halide particles and organic silver salt are mixed with a high-speed stirrer, ball mill, sand mill, colloid mill, vibration mill, homogenizer, etc. There is a method of mixing, or a method of preparing an organic silver salt by mixing photosensitive silver halide prepared at any timing during the preparation of the organic silver salt, etc. There is no particular limitation as long as it appears.

As a method for preparing silver halide used in the present invention, a so-called halation method in which a part of silver of an organic silver salt is halogenated with an organic or inorganic halide is also preferably used. As the organic halide used here, any compound may be used as long as it is a compound that reacts with an organic silver salt to generate a silver halide, but N-halogenoimide (such as N-bromosuccinimide) and a quaternary nitrogen halide compound
(Eg, tetrabutylammonium bromide) and an association of a halogenated quaternary nitrogen salt with a halogen molecule (pyridinium bromide bromide). As the inorganic halogen compound, any compound may be used as long as it is a compound which reacts with an organic silver salt to generate silver halide, and includes an alkali metal or ammonium halide (such as sodium chloride, lithium bromide, potassium iodide, and ammonium bromide). ), Alkali earth metal halides (calcium bromide, magnesium chloride, etc.), transition metal halides (ferric chloride, cupric bromide, etc.), metal complexes with halogen ligands (sodium iridium bromide) , Ammonium rhodate, etc.), halogen molecules
(Bromine, chlorine, iodine). Further, a desired organic / inorganic halide may be used in combination.

In the present invention, the amount of the halide to be added is preferably 1 to 500 mmol, more preferably 10 to 250 mmol, as a halogen atom per 1 mol of the organic silver salt.
mmol is more preferred.

The heat-developable recording material of the present invention preferably contains a reducing agent for an organic silver salt. The reducing agent for the organic silver salt may be any substance that reduces silver ions to metallic silver, preferably an organic substance. Conventional photographic developers such as phenidone, hydroquinone and catechol are useful, but hindered phenol reducing agents are preferred. The reducing agent is preferably contained in an amount of 5 to 50 mol%, more preferably 10 to 40 mol%, per 1 mol of silver on the surface having the image forming layer. The layer to which the reducing agent is added may be any layer on the side having the image forming layer. When it is added to a layer other than the image forming layer, it is preferable to use a relatively large amount of 10 to 50 mol% with respect to 1 mol of silver. Further, the reducing agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a heat-developable recording material using an organic silver salt, a wide range of reducing agents are disclosed in JP-A-46-6074 and JP-A-47-1238.
47-33621, 49-46427, 49-115540, 50-14
No. 334, No. 50-36110, No. 50-147711, No. 51-32632,
No. 51-1023721, No. 51-32324, No. 51-51933, No. 52-8
4727, 55-108654, 56-146133, 57-82828
No. 57-82829, JP-A-6-3793, U.S. Pat.
No. 86, No. 3,679,426, No. 3,751,252, No. 3,751,255
Nos. 3,761,270, 3,782,949, 3,839,048,
3,928,686, 5,464,738, German patent 2321328,
It is disclosed in European Patent No. 692732 and the like. For example, phenylamide oxime, 2-thienylamide oxime and
Amide oximes such as p-phenoxyphenylamide oxime; azines such as 4-hydroxy-3,5-dimethoxybenzaldehyde azine; combinations of 2,2′-bis (hydroxymethyl) propionyl-β-phenylhydrazine with ascorbic acid A combination of such an aliphatic carboxylic acid aryl hydrazide and ascorbic acid; a combination of polyhydroxybenzene and hydroxylamine, reductone and / or hydrazine (eg, hydroquinone and bis (ethoxyethyl) hydroxylamine, piperidinohexose reductone Or a combination of formyl-4-methylphenylhydrazine, etc.); phenylhydroxamic acid, p
Hydroxamic acids such as -hydroxyphenylhydroxamic acid and β-alinine hydroxamic acid; combinations of azines with sulfonamidophenols (eg, phenothiazine and 2,6-dichloro-4-benzenesulfonamidophenol); ethyl-α-cyano Α-cyanophenylacetic acid derivatives such as 2-methylphenylacetate and ethyl-α-cyanophenylacetate; 2,2′-dihydroxy-1,1′-binaphthyl, 6,6′-dibromo-2,2′-dihydroxy Bis-β-naphthol as exemplified by -1,1′-binaphthyl and bis (2-hydroxy-1-naphthyl) methane; bis-β-naphthol and 1,3-dihydroxybenzene derivatives (eg, 2,4
-Dihydroxybenzophenone or 2 ', 4'-dihydroxyacetophenone); 3-methyl-1-phenyl
5-pyrazolone, such as -5-pyrazolone; reductones as exemplified by dimethylaminohexose reductone, anhydrodihydroaminohexose reductone and anhydrodihydropiperidone hexose reductone;
Sulfonamidophenol reducing agents such as 2,6-dichloro-4-benzenesulfonamidophenol and p-benzenesulfonamidophenol; 2-phenylindane-1,3-
Diones and the like; chromanes such as 2,2-dimethyl-7-t-butyl-6-hydroxychroman; 1,4-dihydropyridines such as 2,6-dimethoxy-3,5-dicarboethoxy-1,4-dihydropyridine; Bisphenols (e.g., bis (2-hydroxy
-3-t-butyl-5-methylphenyl) methane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4-ethylidene
-Bis (2-t-butyl-6-methylphenol), 1,1, -bis (2
-Hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane and the like); ascorbic acid derivatives (for example, palmitic acid 1 And aldehydes and ketones such as benzyl and biacetyl; 3-pyrazolidone and certain indan-1,3-diones; chromanol (such as tocopherol). Particularly preferred reducing agents are bisphenol and chromanol.

The reducing agent of the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

When an additive known as a “toning agent” for improving an image is contained, the optical density may be increased. The toning agent may also be advantageous in forming a black silver image. The toning agent is preferably contained in an amount of 0.1 to 50 mol% per mol of silver on the surface having the image forming layer,
More preferably, the content is 0.5 to 20 mol%. Further, the toning agent may be a so-called precursor which is derivatized so as to have a function effectively only during development.

In a heat-developable recording material using an organic silver salt, a wide range of color tones are disclosed in JP-A-46-6077 and JP-A-47-10282.
Nos. 49-5019, 49-5020, 49-91215, 49-9
No. 1215, No. 50-2524, No. 50-32927, No. 50-67132,
No. 50-67641, No. 50-114217, No. 51-3223, No. 51-279
No. 23, No. 52-14788, No. 52-99813, No. 53-1020, No. 5
3-76020, 54-156524, 54-156525, 61-1836
No. 42, JP-A-4-56848, JP-B-49-10727, 54-2033
No. 3, U.S. Pat.Nos. 3,080,254, 3,446,648, 3,782,9
No. 41, No. 4,123,282, No. 4,510,236, British Patent 138079
No. 5, Belgian Patent No. 841910 and the like. Examples of toning agents are phthalimide and N-hydroxyphthalimide; succinimide, pyrazolin-5-one, and quinazolinone, 3-phenyl-2-pyrazolin-5-one, 1-phenylurazole, quinazoline and 2,4-thiazolidinedione Cyclic imides such as; naphthalimides (eg, N
-Hydroxy-1,8-naphthalimide); cobalt complexes (eg, cobalt hexamine trifluoroacetate); 3-
Mercapto-1,2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole Illustrative mercaptans; N- (aminomethyl) aryldicarboximides, such as (N, N-dimethylaminomethyl) phthalimide and N, N- (dimethylaminomethyl)-
Naphthalene-2,3-dicarboximide); and blocked pyrazoles, isothiuronium derivatives and certain photobleaching agents (eg, N, N′-hexamethylenebis (1-carbamoyl-3,5-dimethylpyrazole), 1 , 8- (3,6-diazaoctane) bis (isothiuronium trifluoroacetate) and 2-tribromomethylsulfonyl)-(benzothiazole)); and 3-ethyl-5 [(3-ethyl-2-benzothia) Zolinylidene) -1-methylethylidene] -2-thio-2,4-oxazolidinedione; phthalazinone, phthalazinone derivative or metal salt, or 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7- Derivatives such as dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione; phthalazinone and phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachlorophthalic acid) Combination of anhydride such as phthalic acid); phthalazine, phthalazine derivatives or metal salts or 4- (1-naphthyl)
Derivatives such as phthalazine, 6-chlorophthalazine, 5,7-dimethoxyphthalazine and 2,3-dihydrophthalazine; phthalazine and phthalic acid derivatives (for example, phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid and tetrachloro Quinazolinedione, benzoxazine or naphthoxazine derivatives; rhodium complexes, such as hexachlororhodium, which function not only as a color tone control agent but also as a source of halide ions for silver halide formation in situ (III) ammonium, rhodium bromide, rhodium nitrate and hexachlororhodium (II
I) potassium acid and the like; inorganic peroxides and persulfates, such as ammonium disulfide and hydrogen peroxide;
Benzoxazine-2,4 such as benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione -Diones; pyrimidines and asymmetric-triazines (eg, 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine, etc.), azauracil, and tetraazapentalene derivatives (eg, 3,6-dimercapto-1,4 -Diphenyl-1
H, 4H-2,3a, 5,6a-tetraazapentalene, and 1,4-di
(o-chlorophenyl) -3,6-dimercapto-1H, 4H-2,3a, 5,6
a-tetraazapentalene).

In the present invention, the color tone agent may be added by any method such as a solution, a powder, and a solid fine particle dispersion. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

As the binder for the image forming layer in the present invention, well-known natural or synthetic resins such as gelatin, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, cellulose acetate, and the like can be used.
Any one can be selected from polyolefin, polyester, polystyrene, polyacrylonitrile, polycarbonate and the like. Of course, copolymers and terpolymers are also included. Preferred polymers are polyvinyl butyral, butyl ethyl cellulose, methacrylate copolymer, maleic anhydride copolymer, polystyrene and butadiene-styrene copolymer. If necessary, two or more of these polymers can be used in combination. Such a polymer is used in an amount sufficient to hold the components therein. That is, it is used in a range effective to function as a binder. The effective range can be appropriately determined by those skilled in the art. As a guide when at least the organic silver salt is retained, the ratio of the binder to the organic silver salt is preferably 15: 1 to 1: 2, particularly preferably 8: 1 to 1: 1.

Further, at least one of the image forming layers of the present invention may be an image forming layer containing the polymer latex described below in an amount of 50 wt% or more of the total binder. Hereinafter, this image forming layer is referred to as “the image forming layer of the present invention”, and the polymer latex used for the binder is referred to as “the polymer latex of the present invention”. However, the "polymer latex" referred to here is a water-insoluble hydrophobic polymer dispersed as fine particles in a water-soluble dispersion medium. The dispersion state is such that the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, or partially dispersed in polymer molecules and molecular chains themselves are molecularly dispersed. Any of them may be used. As for the polymer latex of the present invention, "Synthetic resin emulsion
(Edited by Okudadaira and Hiroshi Inagaki, published by the Society of Polymer Publishing (1978)),
`` Applications of synthetic latex (Takaaki Sugimura, Yasuo Kataoka, Soichi Suzuki, Keiji Kasahara, edited by Polymer Publishing Association (1993)) '', `` Chemistry of synthetic latex (Souichi Muroi, published by Polymer Publishing Association (19)
70))). The average particle size of the dispersed particles is 1
The range is preferably about 50,000 nm, more preferably about 5 to 1,000 nm. There is no particular limitation on the particle size distribution of the dispersed particles,
Those having a wide particle size distribution or those having a monodispersed particle size distribution may be used.

As the polymer latex of the present invention, other than a polymer latex having a normal uniform structure, a so-called core / polymer latex may be used.
Shell type latex may be used. In this case, it may be preferable to change the glass transition temperature of the core and the shell.

The minimum film forming temperature (MFT) of the polymer latex of the present invention is from -30 ° C to 90 ° C, more preferably from about 0 ° C to 70 ° C. A film-forming auxiliary may be added to control the minimum film-forming temperature. An organic compound that lowers the minimum film forming temperature of polymer latex, also called a plasticizer
(Usually an organic solvent) and described in, for example, the aforementioned "Synthesis of Synthetic Latex (Souichi Muroi, published by Kobunshi Kankokai (1970))".

Examples of the polymer used in the polymer latex of the present invention include acrylic resin, vinyl acetate resin, polyester resin, polyurethane resin, rubber resin, vinyl chloride resin, vinylidene chloride resin, polyolefin resin, and copolymers thereof. There is. The polymer may be a linear polymer, a branched polymer, or a crosslinked polymer. The polymer may be a so-called homopolymer in which a single monomer is polymerized, or a copolymer in which two or more monomers are polymerized. In the case of a copolymer, it may be a random copolymer or a block copolymer. The molecular weight of the polymer is preferably from 500 to 100,000, more preferably from 10,000 to 100,000 in number average molecular weight.
It is about 100000. If the molecular weight is too small, the mechanical strength of the image forming layer is insufficient, and if it is too large, the film-forming properties are poor, which is not preferable.

The polymer of the polymer latex used in the present invention preferably has an equilibrium water content at 25 ° C. and 60% RH of 2% by weight or less, more preferably 1% by weight or less. The lower limit of the equilibrium water content is not particularly limited, but is preferably 0.01% by weight, more preferably 0.03% by weight. For the definition and measurement method of the equilibrium moisture content, see, for example,
4, Polymer Material Testing Method (edited by the Society of Polymer Science, Jinjinshokan) ”and so on.

Specific examples of the polymer latex used as a binder for the image forming layer of the heat-developable recording material of the present invention include the following. Latex of methyl methacrylate / ethyl acrylate / methacrylic acid copolymer, latex of methyl methacrylate / 2 ethylhexyl acrylate / styrene / acrylic acid copolymer, latex of styrene / butadiene / acrylic acid copolymer, latex of styrene / butadiene / divinylbenzene / methacrylic acid copolymer, Latex of methyl methacrylate / vinyl chloride / acrylic acid copolymer, latex of vinylidene chloride / ethyl acrylate / acrylonitrile / methacrylic acid copolymer and the like.
Such polymers are also commercially available, and the following polymers can be used. For example, as examples of acrylic resin, Sebian A-4635,46583,4601 (all manufactured by Daicel Chemical Industries, Ltd.), Nipol Lx811,814,821,820,857
(Nippon Zeon Co., Ltd.) and other polyester resins, such as FINETEX ES650, 611, 675, 850 (Dai Nippon Ink Chemical Co., Ltd.), WD-size, WMS (Eastman Chemical Co., Ltd.), etc. HYDRAN AP10 as polyurethane resin,
LACSTAR 7310K, 3307B, 4700H, 7132C as rubber resins such as 20, 30, 40 (all manufactured by Dainippon Ink and Chemicals, Inc.)
(Dai Nippon Ink Chemical Co., Ltd.), Nipol Lx416, 41
0, 438C, 2507, (Nippon Zeon Co., Ltd.) and other vinyl chloride resins such as G351 and G576 (Nippon Zeon Co., Ltd.)
Examples of the vinylidene chloride resin include L502 and L513 (all manufactured by Asahi Kasei Kogyo Co., Ltd.), and olefin resins include Chemipearl S120 and SA100 (all manufactured by Mitsui Petrochemical Co., Ltd.). These polymers may be used alone or as a blend of two or more as necessary.

The image forming layer of the present invention comprises 50 wt.
% Or more of the polymer latex is preferably used, and more preferably 70 wt% or more of the polymer latex.

In the image forming layer of the present invention, if necessary, a hydrophilic polymer such as gelatin, polyvinyl alcohol, methylcellulose, hydroxypropylcellulose, carboxymethylcellulose and hydroxypropylmethylcellulose is added in an amount of 50% by weight or less of the whole binder. Is also good. The addition amount of these hydrophilic polymers is preferably 30% by weight or less of the total binder in the image forming layer.

The image forming layer of the present invention can be prepared by applying an aqueous coating solution and then drying. However, the term “aqueous” used herein means that 30% by weight or more of the solvent (dispersion medium) of the coating liquid is water. As components other than water of the coating solution, water-miscible organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, methyl cellosolve, ethyl cellosolve, dimethylformamide, and ethyl acetate can be used. Specific examples of the solvent composition include the following. Water / methanol = 90/10, water / methanol = 70/30, water / ethanol = 90/10, water / isopropanol = 90/10, water / dimethylformamide = 95/5, water /
Methanol / dimethylformamide = 80/15/5, water / methanol / dimethylformamide = 90/5/5. (However, the numbers represent wt%.)

Further, the method described in US Pat. No. 5,496,695 can also be used.

The total amount of the binder in the image forming layer of the present invention is 0.1.
The range is preferably ^{2 to} 30 g / m ² , more preferably 1 to 15 g / m ² . A crosslinking agent for crosslinking and a surfactant for improving coating properties may be added to the image forming layer of the invention.

As the sensitizing dye in the present invention, any dye can be used as long as it can spectrally sensitize silver halide grains in a desired wavelength region when adsorbed on silver halide grains. As the sensitizing dye, a cyanine dye, a merocyanine dye, a complex cyanine dye, a complex merocyanine dye, a holopolar cyanine dye, a styryl dye, a hemicyanine dye, an oxonol dye, a hemioxonol dye, and the like can be used. Useful sensitizing dyes for use in the present invention include, for example, RESEARCH DISCLOSURE Item 17
Item 643IV-A (p.23, December 1978), Item 1831X (August 1979)
p.437) or in the literature cited. In particular, a sensitizing dye having a spectral sensitivity suitable for the spectral characteristics of the light source of various laser imagers, scanners, imagesetters and plate making cameras can be advantageously selected.

As an example of spectral sensitization to red light, He-Ne
For lasers, so-called red light sources such as red semiconductor lasers and LEDs, I-1 to I-1 described in JP-A-54-18726.
-38, the compound of I-1 to I-35 described in JP-A-6-75322 and the compound of I-1 to I-34 described in JP-A-7-287338, JP-B-55-39818 Dyes 1 to 20 described, compounds of I-1 to I-37 described in JP-A-62-284343 and compounds of I-1 to I-34 described in JP-A-7-287338 are advantageously selected. Is done.

For a semiconductor laser light source in the wavelength range of 750 to 1400 nm, various known dyes including cyanine, merocyanine, styryl, hemicyanine, oxonol, hemioxonol and xanthene dyes are spectrally advantageously sensitized. Can be done. Useful cyanine dyes are, for example, cyanine dyes having basic nuclei such as thiazoline nuclei, oxazoline nuclei, pyrroline nuclei, pyridine nuclei, oxazole nuclei, thiazole nuclei, selenazole nuclei and imidazole nuclei. Preferred useful merocyanine dyes include, in addition to the above basic nuclei, acidic nuclei such as thiohydantoin nucleus, rhodanine nucleus, oxazolidinedione nucleus, thiazolinedione nucleus, barbituric acid nucleus, thiazolinone nucleus, malononitrile nucleus and pyrazolone nucleus. Including. Among the above cyanine and merocyanine dyes, those having an imino group or a carboxyl group are particularly effective. For example, U.S. Patent 3,761,279,
3,719,495 and 3,877,943, British Patent 1,466,201
No. 1,469,117, No. 1,422,057, Tokuhei 3-10391
No. 6-52387, JP-A-5-341432, 6-94781,
It may be appropriately selected from known dyes as described in JP-A-6-301141.

Particularly preferred as the structure of the dye used in the present invention is a cyanine dye having a thioether bond-containing substituent (for example, see JP-A-62-58239 and JP-A-3-13863).
No.8, No.3-138642, No.4-255840, No.5-72659, No.5-
72661, 6-222491, 2-230506, 6-258757
No., 6-317868, 6-324425, Tokuyohei 7-500926,
Dyes described in U.S. Pat.No. 5,541,054), dyes having a carboxylic acid group (for example, JP-A-3-163440, 6-30114
No. 1, U.S. Pat.No. 5,441,899), merocyanine dyes, polynuclear merocyanine dyes and polynuclear cyanine dyes
(JP 47-6329, JP 49-105524, JP 51-127719, JP
52-80829, 54-61517, 59-214846, 60-6750
No. 63-159841, JP-A-6-35109, JP-A-6-59381,
Nos. 7-146537, 7-46537, JP-T-55-50111, British Patent 1,467,638, and US Pat. No. 5,281,515).

Also, dyes described in Example 5 of US Pat. Nos. 5,510,236 and 3,871,887 as dyes forming a J-band,
JP-A-2-96131 and JP-A-59-48753 are disclosed and can be preferably used in the present invention.

These sensitizing dyes may be used alone.
Two or more kinds may be used in combination. Combinations of sensitizing dyes are often used, especially for supersensitization. Along with the sensitizing dye, the emulsion may contain a dye which does not itself have a spectral sensitizing effect or a substance which does not substantially absorb visible light and exhibits supersensitization. Useful sensitizing dyes, combinations of dyes exhibiting supersensitization and substances exhibiting supersensitization are
Research Disclosure Volume 176, 17643 (December 1978) No. 23
Section IV of Page IV, or JP-B-49-25500, 43-43933,
These are described in JP-A-59-19032 and JP-A-59-192242.

The sensitizing dyes used in the present invention may be used in combination of two or more. To add sensitizing dyes to a silver halide emulsion, they may be directly dispersed in the emulsion,
Or water, methanol, ethanol, propanol,
Acetone, methyl cellosolve, 2,2,3,3-tetrafluoropropanol, 2,2,2-trifluoroethanol, 3-methoxy-1-propanol, 3-methoxy-1-butanol, 1-methoxy-2-propanol , N, N-dimethylformamide or the like, alone or in a mixed solvent, and added to the emulsion.

As disclosed in US Pat. No. 3,469,987, a dye is dissolved in a volatile organic solvent, and this solution is dispersed in water or a hydrophilic colloid. Method of adding to Japanese Patent Publication No. 44-23389,
As disclosed in JP-A-44-27555 and JP-A-57-22091, a dye is dissolved in an acid and this solution is added to the emulsion, or an acid or base is added to the emulsion as an aqueous solution in the presence of an acid or base. A method of adding an aqueous solution or a colloidal dispersion in the presence of a surfactant to an emulsion as disclosed in U.S. Patent Nos. 3,822,135 and 4,006,025, JP-A-51-746, a method in which a dye is directly dispersed in a hydrophilic colloid and the dispersion is added to an emulsion as disclosed in JP-A-51-746.
As disclosed in JP-A No. 24, a method of dissolving a dye using a compound that causes a red shift and adding this solution to an emulsion can also be used. Also, ultrasonic waves can be used for dissolution.

The sensitizing dye used in the present invention may be added to the silver halide emulsion of the present invention at any stage of the emulsion preparation which has been found to be useful. For example, U.S. Patents 2,735,766 and 3,628,960,
4,183,756, 4,225,666, JP-A-58-184142,
As disclosed in the specification of JP-A-60-196749 and the like, the timing before silver halide grain forming step and / or desalting, during and / or after desalting and before the start of chemical ripening. As disclosed in the specification such as JP-A-58-113920, any time immediately before chemical ripening or during the process, after chemical ripening, and before coating the emulsion before coating It may be added at the time and in the process.
Further, as disclosed in the specification of U.S. Pat. No. 4,225,666, JP-A-58-7629, etc., the same compound may be used alone or in combination with a compound having a different structure, for example, during the particle forming step. The compound may be divided and added during the ripening step or after the completion of the chemical ripening, or may be added separately before or during the chemical ripening or after the completion of the chemical ripening. May be added.

The amount of the sensitizing dye used in the present invention may be a desired amount according to the performance such as sensitivity and fog.
The amount is preferably from 10 ^-6 to 1 mol, more preferably from 10 ^-4 to 10 ^-1 mol, per mol of silver halide in the image forming layer.

The silver halide emulsion according to the invention or /
And organic silver salts can be further protected against the formation of additional fog by antifoggants, stabilizers and stabilizer precursors, and can be stabilized against reduced sensitivity during storage in inventory. Suitable antifoggants, stabilizers and stabilizer precursors that can be used alone or in combination are the thiazonium salts described in U.S. Pat.Nos. 2,131,038 and 2,694,716, U.S. Pat. Azaindene, U.S. Pat.
8,663 mercury salt, U.S. Pat.No. 3,287,135 urazole, U.S. Pat.
Nitrone, nitroindazole, U.S. Patent No. 2,839,405
No. 3,220,839, thiuronium salts, and U.S. Pat.Nos. 2,566,263 and 2,597,915, palladium, platinum and gold salts, U.S. Pat.Nos. 4,108,665 and 4,442,202 No. 4,128,557
Nos. 4,137,079 and 4,138,365 and 4,
No. 4,59,350 and U.S. Pat.
And the phosphorus compounds described in No. 1,985.

The antifoggant preferably used in the present invention is an organic halide.
No. 50-120328, No. 51-121332, No. 54-58022, No.
56-70543, 56-99335, 59-90842, 61-12964
No. 2, 62-129845, JP-A-6-208191, 7-5621,
Nos. 7-2781, 8-15809, U.S. Pat.
Compounds such as those disclosed in US Pat.

The antifoggant of the present invention may be added by any method such as a solution, a powder, and a dispersion of solid fine particles. The dispersion of the solid fine particles is carried out by a known means for making fine (for example, a ball mill, a vibration ball mill, a sand mill, a colloid mill, a jet mill, a roller mill, etc.). When dispersing the solid fine particles, a dispersing aid may be used.

Although not required to practice the present invention,
It may be advantageous to add a mercury (II) salt as an antifoggant to the emulsion layer. Preferred mercury (II) salts for this purpose are
Mercury acetate and mercury bromide. The amount of mercury used in the present invention is preferably 1 nmol to 1 mmol, more preferably 10 nmol to 1 mol per mol of silver applied.
It is in the range of 100 μmol.

The heat-developable recording material of the present invention may contain benzoic acids for the purpose of increasing the sensitivity and preventing fog. The benzoic acids of the present invention may be any benzoic acid derivative,
Examples of preferred structures are described in U.S. Pat.
4,152,160, Japanese Patent Application Nos. 8-151242, 8-151241, 8-9
8051 and the like. The benzoic acids of the present invention may be added to any part of the recording material,
The additive layer is preferably added to the layer having the image forming layer, and more preferably to the organic silver salt-containing layer. The benzoic acid of the present invention may be added at any time during the preparation of the coating solution, and when it is added to the organic silver salt-containing layer, it may be added at any time from the preparation of the organic silver salt to the preparation of the coating solution. It is preferable after salt preparation and immediately before application. The benzoic acid of the present invention may be added by any method such as powder, solution, and fine particle dispersion. Further, it may be added as a solution mixed with other additives such as a sensitizing dye, a reducing agent and a color tone agent. The benzoic acid of the present invention may be added in any amount, but may be added in an amount of 1 to 1 mol of silver.
It is preferably from μmol to 2 mol, more preferably from 1 mmol to 0.5 mol.

In the present invention, a mercapto compound, a disulfide compound, and a thione compound are contained in order to suppress or accelerate development to control development, to improve spectral sensitization efficiency, to improve storage stability before and after development, and the like. be able to.

When a mercapto compound is used in the present invention, it may be of any structure, but may be any of Ar-SM, Ar-SSA
Those represented by r are preferred. In the formula, M is a hydrogen atom or an alkali metal atom, and Ar is an aromatic or condensed aromatic ring group having one or more nitrogen, sulfur, oxygen, selenium or tellurium atoms. Preferably, the heteroaromatic ring in these groups is benzimidazole, naphthimidazole, benzothiazole, naphthothiazole, benzoxazole, naphthoxazole, benzoselenazole, benzotellurazole, imidazole, oxazole, pyrazole, triazole, thiadiazole, tetrazole, Triazine, pyrimidine, pyridazine, pyrazine, pyridine, purine, quinoline or quinazolinone. The heteroaromatic ring includes, for example, halogens (e.g., Br and Cl), hydroxy, amino, carboxy,
Alkyl (e.g. one or more carbon atoms, preferably 1-4
Having one carbon atom) and alkoxy (e.g.,
One having at least one carbon atom, preferably having 1 to 4 carbon atoms). As mercapto-substituted heteroaromatic compounds, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, 2-mercaptobenzothiazole
Mercapto-5-methylbenzimidazole, 6-ethoxy-
2-mercaptobenzothiazole, 2,2'-dithiobis-benzothiazole, 3-mercapto-1,2,4-triazole, 4,5
-Diphenyl-2-imidazolethiol, 2-mercaptoimidazole, 1-ethyl-2-mercaptobenzimidazole, 2-mercaptoquinoline, 8-mercaptopurine, 2-mercapto-4 (3H) -quinazolinone, 7-trifluoromethyl-
4-quinolinethiol, 2,3,5,6-tetrachloro-4-pyridinethiol, 4-amino-6-hydroxy-2-mercaptopyrimidine monohydrate, 2-amino-5-mercapto-1,3,4 -
Thiadiazole, 3-amino-5-mercapto-1,2,4-triazole, 4-hydroxysiloxy-2-mercaptopyrimidine, 2-mercaptopyrimidine, 4,6-diamino-2-mercaptopyrimidine, 2-mercapto-4-methyl Pyrimidine hydrochloride, 3-mercapto-5-phenyl-1,2,4-triazole,
Examples include 2-mercapto-4-phenyloxazole, but the present invention is not limited thereto.

The addition amount of these mercapto compounds is preferably in the range of 0.001 to 1.0 mol per mol of silver in the emulsion layer, more preferably 0.01 to 0.3 mol per mol of silver.
It is a molar amount.

The heat-developable recording material of the present invention may contain a nucleation promoting agent which promotes the action of the nucleating agent.

Examples of the nucleation accelerator used in the present invention include:
Examples include amine derivatives, onium salts, disulfide derivatives or hydroxymethyl derivatives, hydroxamic acid derivatives, acyl hydrazide derivatives, acrylonitrile derivatives, hydrogen donors, and the like. Examples are listed below. Compounds described in JP-A-7-77783, page 48, lines 2 to 37, specifically compounds A-1) to A-73) described on pages 49 to 58.
Compounds represented by (Chemical Formula 21), (Chemical Formula 22) and (Chemical Formula 23) described in JP-A-7-84331.
Compound described on page 8. Compounds represented by general formula [Na] and general formula [Nb] described in JP-A-7-104426, specifically, compounds of Na-1 to Na-22 described on pages 16 to 20 of the same publication And Nb-1 to Nb-12. Japanese Patent Application 7-3781
Represented by general formula (1), general formula (2), general formula (3), general formula (4), general formula (5), general formula (6) and general formula (7) described in No. 7 Compounds, specifically, the compounds of 1-1 to 1-19, the compounds of 2-1 to 2-22, 3-1
~ 3-36 compounds, 4-1 ~ 4-5 compounds, 5-1 ~ 5-41 compounds, 6-1 ~ 6-58 compounds and 7-1 ~ 7-38 compounds. U.S. Pat.No. 5,554,505, page 19, line 43 to page 22, line 3; U.S. Pat.No. 5,554,507, page 17, line 43 to page 18, line 53; U.S. Pat. Compounds described in line 14; U.S. Pat. No. 5,558,983; page 16, line 31 to page 17, line 12; and WO 97/11407, page 27, line 4 to page 32, line 7. A nucleation accelerator described in Japanese Patent Application No. 8-70908.

The nucleation promoter of the present invention may be water or a suitable organic solvent such as alcohols (methanol, ethanol, propanol, fluorinated alcohol), ketones (acetone, methyl ethyl ketone), dimethylformamide, dimethyl sulfoxide, methyl cellosolve. It can be used by dissolving it in, for example.

Further, by a well-known emulsification and dispersion method, an oil such as dibutyl phthalate, tricresyl phosphate, glyceryl triacetate or diethyl phthalate, or an auxiliary solvent such as ethyl acetate or cyclohexanone is used to dissolve and dissolve. An emulsified dispersion can be prepared and used. Alternatively, a powder of a nucleation accelerator can be dispersed in water by a ball mill, a colloid mill, or ultrasonic waves by a method known as a solid dispersion method, and used.

The nucleation accelerator of the present invention may be added to the layer on the image forming layer side with respect to the support, that is, to the image forming layer or any other layer. It is preferred to add.

The addition amount of the nucleation accelerator of the present invention is preferably 1 × 10 ^-6 to 2 × 10 ^-1 mol per mol of silver, and more preferably 1 × 10 ^-5 to 1 × 10 ^-5 .
2 × 10 ⁻² mol is more preferred, and 2 × 10 ⁻⁵ to 1 × 10 ⁻² mol is most preferred.

In the image forming layer according to the invention, a polyhydric alcohol (for example, US Pat.
Glycerin and diols of the type described in U.S. Pat. No. 2,960,404), fatty acids or esters described in U.S. Pat. Nos. 2,588,765 and 3,121,060, and silicone resins described in British Patent No. 955,061.

The heat-developable recording material of the present invention may be provided with a surface protective layer for the purpose of preventing adhesion of the image forming layer.

The binder for the surface protective layer of the present invention may be any polymer, but preferably contains a polymer having a carboxylic acid residue in an amount of 100 mg / m ^{2 to} 5 g / m ² . Examples of the polymer having a carboxyl residue include natural polymers (gelatin, alginic acid, etc.), modified natural polymers (carboxymethylcellulose, phthalated gelatin, etc.), synthetic polymers (polymethacrylate, polyacrylate, polyalkyl methacrylate / acrylate). Copolymer, polystyrene / polymethacrylate copolymer, etc.). The content of carboxy residues in such a polymer is 10 mmol or more per 100 g of the polymer 1.
It is preferably at most 4 mol. The carboxylic acid residue may form a salt with an alkali metal ion, an alkaline earth metal ion, an organic cation, or the like.

As the surface protective layer of the present invention, any anti-adhesion material may be used. Examples of anti-adhesion materials include waxes, silica particles, styrene-containing elastomeric block copolymers (e.g., styrene-butadiene-
Styrene, styrene-isoprene-styrene), cellulose acetate, cellulose acetate butyrate, cellulose propionate, and mixtures thereof. Further, a crosslinking agent for crosslinking and a surfactant for improving coating properties may be added to the surface protective layer.

In the image forming layer or the protective layer of the image forming layer in the invention, US Pat. Nos. 3,253,921 and 2,27
Light absorbing substances and filter dyes as described in 4,782, 2,527,583 and 2,956,879 can be used. Also, for example, U.S. Pat.
The dye can be mordanted as described in US Pat. As the amount of filter dye used, the absorbance at the exposure wavelength is 0.
1-3 are preferable, and 0.2-1.5 are particularly preferable.

The image-forming layer or the protective layer of the image-forming layer in the present invention may comprise a matting agent such as starch, titanium dioxide, zinc oxide, silica, of the type described in US Pat. Nos. 2,992,101 and 2,701,245. Polymer beads, including beads, can be included. The matte degree of the emulsion surface may be any value as long as stardust failure does not occur, but the Beck smoothness is preferably from 200 seconds to 10,000 seconds, particularly preferably from 300 seconds to 10,000 seconds.

The heat-developable photographic emulsion of the present invention is contained in one or more layers on a support. One layer construction must include optional additional materials such as organic silver salts, silver halides, developers and binders, and toning agents, coating aids and other auxiliaries. The two-layer configuration is
One must contain the organic silver salt and silver halide in one emulsion layer (usually the layer adjacent to the support) and some other components in the second or both layers. However, a two-layer construction comprising a single emulsion layer containing all components and a protective topcoat is also contemplated. The construction of a multicolor photothermographic material may include a combination of these two layers for each color, and may include all components in a single layer as described in U.S. Pat.No. 4,708,928. Is also good. In the case of a multi-dye, multi-color photothermographic material, each emulsion layer is generally, as described in U.S. Pat.No. 4,460,681,
By using a functional or non-functional barrier layer between each emulsion layer (photosensitive layer), it is kept distinct from each other.

In the image forming layer of the present invention, various dyes and pigments can be used from the viewpoint of improving color tone and preventing irradiation. Dyes and pigments used in the image recording layer of the present invention may be any, for example, pigments and dyes described in the color index, specifically, pyrazoloazole dye, anthraquinone dye, azo dye, azomethine dye, oxonol dye, Carbocyanine dye, styryl dye, triphenylmethane dye, indoaniline dye,
Organic pigments such as indophenol dyes and phthalocyanines, and inorganic pigments. Preferred dyes used in the present invention include anthraquinone dyes (e.g., compounds 1 to 9 described in JP-A-5-341441, compounds 3-6 to 18 and 3-23 to 38 described in JP-A-5-165147), azomethine Dyes (e.g., compounds 17 to 47 described in JP-A-5-341441), indoaniline dyes (e.g., compound 1 described in JP-A-5-289227)
1 to 19, compound 47 described in JP-A-5-341441, JP-A-5-165
And the azo dyes (compounds 10 to 16 described in JP-A-5-341441). As a method for adding these dyes, any method such as a solution, an emulsion, a solid fine particle dispersion, and a state in which the dye is mordanted with a polymer mordant may be used. The amount of these compounds used is determined depending on the desired absorption amount, but it is generally preferable to use them in an amount of 1 μg or more and 1 g or less per 1 m ² .

In the present invention, the antihalation layer can be provided on the side farther from the light source than the image forming layer. The antihalation layer preferably has a maximum absorption in a desired wavelength range of 0.1 or more and 2 or less, more preferably an absorption of an exposure wavelength of 0.2 or more and 1.5 or less, and an absorption in a visible region after processing of 0.001 or more. It is preferably less than 0.2, and more preferably a layer having an optical density of 0.001 or more and less than 0.15.

When antihalation dyes are used in the present invention, these dyes have the desired absorption in the wavelength range, have a sufficiently low absorption in the visible region after treatment, and have the desired absorbance spectrum of the antihalation layer. Any compound can be used as long as it is possible. For example, the following are disclosed, but the present invention is not limited thereto. As a single dye, JP-A-59-56458, JP-A-Hei 2-
216140, 7-13295, 711432, U.S. Patent 5,380,
No. 635, JP-A-2-68539, page 13, lower left column, line 1 to page 14, lower left column, line 9, and JP-A-3-24539, page 14, lower left column, page 16, lower right column The dyes that can be decolorized by the treatment include JP-A-52-139136, JP-A-53-132334, and
56-501480, 57-16060, 57-68831, 57-1018
No. 35, 59-182436, JP-A-7-36145, 7-199409
No., JP-B-48-33692, JP-B-50-16648, JP-B2-41734
Nos., U.S. Pat.Nos. 4,088,497, 4,283,487, 4,548,89
No. 6 and 5,187,049.

The heat-developable recording material of the present invention is preferably a so-called single-sided recording material having at least one image forming layer on one side of a support and a back layer on the other side.

In the present invention, a matting agent may be added for improving transportability. The matting agent is generally fine particles of an organic or inorganic compound insoluble in water. Any matting agent can be used, for example, U.S. Pat.
No. 213, No. 2,701,245, No. 2,322,037, No. 3,262,782
Nos. 3,539,344, 3,767,448, etc., the organic matting agents described in each specification, 1,260,772, 2,192,241, 3,3
257,206, 3,370,951, 3,523,022, 3,769,0
Those well known in the art, such as an inorganic matting agent described in each specification such as No. 20, can be used. For example, specifically, examples of organic compounds that can be used as a matting agent include, as examples of water-dispersible vinyl polymers, polymethyl acrylate, polymethyl methacrylate, polyacrylonitrile, acrylonitrile-α-methylstyrene copolymer, and polystyrene. , Styrene-divinylbenzene copolymer, polyvinyl acetate, polyethylene carbonate, polytetrafluoroethylene, etc., examples of cellulose derivatives such as methylcellulose, cellulose acetate, cellulose acetate propionate, etc., and starch derivatives such as carboxy starch, carboxynitrophenyl Gelatin hardened with a known hardener such as starch, urea-formaldehyde-starch reactant, and hardened gelatin formed into microcapsule hollow granules by coacervate hardening are preferably used. Can be. As examples of the inorganic compound, silicon dioxide, titanium dioxide, magnesium dioxide, aluminum oxide, barium sulfate, calcium carbonate, silver chloride desensitized by a known method, silver bromide, glass, and diatomaceous earth can be preferably used. The above matting agents can be used by mixing different types of substances as necessary. The size and shape of the matting agent are not particularly limited, and those having an arbitrary particle size can be used. In practicing the present invention, it is preferable to use one having a particle size of 0.1 μm to 30 μm. Further, the particle size distribution of the matting agent may be narrow or wide. On the other hand, since the matting agent greatly affects the haze of the coating film and the surface gloss, the particle size, shape, and particle size distribution can be adjusted as necessary during the preparation of the matting agent or by mixing a plurality of matting agents. preferable.

In the present invention, the matte degree of the back layer is preferably such that the Bekk smoothness is 250 seconds or less and 10 seconds or more, and more preferably 180 seconds or less and 50 seconds or more.

In the present invention, the matting agent comprises the outermost surface layer of the heat-developable recording material or a layer functioning as the outermost surface layer;
Alternatively, it is preferably contained in a layer near the outer surface, and is preferably contained in a layer acting as a so-called protective layer.

In the present invention, suitable binders for the back layer are transparent or translucent, generally colorless, and natural polymer synthetic resins, polymers and copolymers, and other film-forming media such as: gelatin, gum arabic, poly (vinyl) (Alcohol), hydroxyethyl cellulose, cellulose acetate, cellulose acetate butyrate, poly (vinyl pyrrolidone), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (Styrene-maleic anhydride), copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinylacetal) s (e.g., poly (vinylformal) and poly (vinylformal))
(Vinyl butyral)), poly (ester) s, poly (urethanes), phenoxy resin, poly (vinylidene chloride), poly (vinylidene chloride)
(Epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, and poly (amides). The binder may be coated from water or an organic solvent or an emulsion.

In the present invention, the back layer preferably has a maximum absorption of 0.3 or more and 2 or less in a desired wavelength range.
More preferably the absorption is 0.5 or more and 2 or less, and the absorption in the visible region after the treatment is preferably 0.001 or more and less than 0.5, and more preferably a layer having an optical density of 0.001 or more and less than 0.3. . Examples of the antihalation dye used in the back layer are the same as those of the antihalation layer described above.

US Pat. Nos. 4,460,681 and 4,374,9
Backside resistive heating layer as shown in No. 21
stive heating layer) can be used in the image recording heat development photographic image system.

A hardener may be used in each layer such as the image forming layer, the protective layer and the back layer of the present invention. Examples of hardeners include U.S. Pat.No. 4,281,060, polyisocyanates described in JP-A-6-208193, U.S. Pat.
Epoxy compounds described in No. 2, etc.
Vinyl sulfone compounds described in 89048 and the like are used.

In the present invention, a surfactant may be used for the purpose of improving coating properties and charging. As the surfactant, any surfactant such as nonionic, anionic, cationic, and fluorine can be used as appropriate. Specifically,
No. 62-170950, Fluoropolymer surfactants described in U.S. Pat.No. 5,380,644, JP-A-60-244945, JP-A-63-18
8135 No. fluorinated surfactants described in U.S. Pat.
No. 5,965, and the like, and polysiloxy acid-based surfactants described in JP-A-6-301140 and the like, and polyalkylene oxide and anionic surfactants.

Examples of the solvent used in the present invention include a new edition solvent pocket book (Ohm Co., 1994), but the present invention is not limited thereto. The solvent used in the present invention has a boiling point of 40 ° C or more and 180 ° C or more.
C. or lower is preferred.

Examples of the solvent of the present invention include hexane, cyclohexane, toluene, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, ethyl acetate, 1,1,1-trichloroethane, tetrahydrofuran,
Triethylamine, thiophene, trifluoroethanol, perfluoropentane, xylene, n-butanol,
Phenol, methyl isobutyl ketone, cyclohexanone, butyl acetate, diethyl carbonate, chlorobenzene, dibutyl ether, anisole, ethylene glycol diethyl ether, N, N-dimethylformamide, morpholine,
Examples include propane sultone, perfluorotributylamine, and water.

The emulsion for heat development in the present invention can be coated on various supports. A typical support is
Polyester film, undercoat polyester film,
Poly (ethylene terephthalate) film, polyethylene naphthalate film, cellulose nitrate film, cellulose ester film, poly (vinyl acetal)
Including films, polycarbonate films and related or resinous materials, as well as glass, paper, metal and the like. Flexible substrates, especially baryta paper, partially acetylated, coated with α-olefin polymers, especially polymers of α-olefins having 2 to 10 carbon atoms such as polyethylene, polypropylene, ethylene-butene copolymer A paper support is typically used. The support may be transparent or opaque, but is preferably transparent.

The heat-developable recording material of the present invention comprises an antistatic or conductive layer such as a soluble salt (for example, chloride or nitrate), a vapor-deposited metal layer, US Pat. Nos. 2,861,056 and
It may have a layer containing an ionic polymer as described in 3,206,312 or an insoluble inorganic salt as described in US Pat. No. 3,428,451.

A method for obtaining a color image using the heat-developable recording material in the present invention is described in JP-A-7-13295, page 10, left column 4
There is a method described from the third line to the 11th left column, 40th line. Also, as a stabilizer for color dye images, UK Patent No. 1,326,889
No. 3,432,300, U.S. Pat.No. 3,698,909, U.S. Pat.
Nos. 574,627, 3,573,050, 3,764,337 and 4,042,394.

The photothermographic emulsions of the present invention can be coated by various coating operations including dip coating, air knife coating, flow coating or extrusion coating using a hopper of the type described in US Pat. No. 2,681,294. If desired, two or more layers can be coated simultaneously by the methods described in US Pat. No. 2,761,791 and British Patent No. 837,095.

Additional layers in the heat-developable recording material of the present invention, such as a dye-receiving layer for receiving a moving dye image, an opaque layer if reflective printing is desired, a protective topcoat layer and photothermographic techniques It may include a known primer layer and the like. It is preferable that the recording material of the present invention can form an image with only one material, and it is preferable that a functional layer necessary for image formation such as an image receiving layer does not become another material.

The heat-developable recording material of the present invention may be developed by any method, but is usually developed by elevating the temperature of the image-wise exposed recording material. The preferred development temperature is 80 to 250 ° C, more preferably 100 to 140 ° C. The development time is preferably from 1 to 180 seconds, more preferably from 10 to 90 seconds.

The heat-developable recording material of the present invention may be exposed by any method, but a laser beam is preferred as an exposure light source. As the laser beam according to the present invention, a gas laser, a YAG laser, a dye laser, a semiconductor laser and the like are preferable. Further, a semiconductor laser and a second harmonic generation element can be used.

When the heat-developable recording material of the present invention contains no photosensitive silver halide, the heat-developable recording material of the present invention can form a latent image by heating. Heating can be performed directly by using a thermal head, or by indirect heating in the presence of a material (dye, pigment, etc.) that absorbs a specific wavelength and converts it into heat in the recording material. But it is good. The light source used at this time is preferably the laser beam described above. Furthermore, these can be combined. When a latent image is formed by heating, a two-step process of forming a latent image by heating in a first step and forming an image in a second step may be performed. It can be performed up to the formation.

[0218]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. First, the structural formulas of the compounds used in the following examples are shown.

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Example 1 (Preparation of silver halide grains A) In 900 ml of water, 7.5 g of inert gelatin and 10 mg of potassium bromide were dissolved, the pH was adjusted to 3.0 at a temperature of 35 ° C., and 370 ml of an aqueous solution containing 74 g of silver nitrate was obtained.
And potassium bromide and potassium iodide in a molar ratio of 94: 6
An aqueous solution containing K ₃ [IrCl ₆ ] was added over 10 minutes by the control double jet method while maintaining the pAg at 7.7. (Ir
Cl ₆ ] ^3- was added in an amount of 3 × 10 ⁻⁷ mol per mol of silver. Thereafter, 0.3 g of 4-hydroxy-6-methyl-1,3,3a, 7-tetrazaindene was added, the pH was adjusted to 5 with NaOH, the average size was 0.06 μm, the projected area variation coefficient was 8%, {100} Area ratio
87% of cubic silver iodobromide grains were obtained. This emulsion was subjected to coagulation sedimentation using a gelatin coagulant, and after desalting, 0.1 g of phenoxyethanol was added to adjust the pH to 5.9 and the pAg to 7.5.

(Preparation of Organic Acid Silver Emulsion A) Behenic acid 10.6
g and distilled water (300 ml) were mixed at 90 ° C. for 15 minutes, 1N-NaOH aqueous solution (31.1 ml) was added over 15 minutes with vigorous stirring, and the mixture was allowed to stand for 1 hour and then cooled to 30 ° C. Next, 7 ml of a 1N-phosphoric acid aqueous solution was added, and 0.13 g of N-bromosuccinimide (C-2) was added while stirring more vigorously.
It was added in molar amounts. Furthermore, 1N-silver nitrate aqueous solution 2
5 ml was continuously added over 2 minutes, and stirring was continued for 90 minutes. After adding 37 g of a 1.2% by weight butyl acetate solution of polyvinyl acetate to the aqueous mixture to form flocs of the dispersion,
The water was removed, and two more water washes and water removals were performed. Thereafter, 20 g of a 2.5 wt% mixed solution of polyvinyl butyral (Denka Butyral # 3000-K, manufactured by Denki Kagaku Kogyo KK) and 1: 2 isopropyl alcohol was added with stirring. Thereafter, 7.8 g of polyvinyl butyral (Denka Butyral # 4000-2 manufactured by Denki Kagaku Kogyo Co., Ltd.) and 57 g of 2-butanone were added to the thus obtained mixture of the gelled organic acid and silver halide, and the mixture was dispersed with a homogenizer. , Silver behenate emulsion (average minor axis 0.04 μm, average major axis 1 μm, coefficient of variation 30%
Needle-shaped particles).

(Preparation of Emulsion Layer Coating Solution A) The following chemicals were added to the above-obtained organic acid silver emulsion in the following amounts per mole of silver. Sodium phenylthiosulfonate at 25 ° C
10 mg, sensitizing dye A 25 mg, sensitizing dye B 20 mg, sensitizing dye C
18 mg of 2-mercapto-5-methylbenzimidazole (C
-1) 2g, 4-chlorobenzophenone-2-carboxylic acid (C-3)
21.5 g, 2-butanone 580 g, and dimethylformamide 220 g were added with stirring and left for 3 hours. Next, 4 g of 4,6-ditrichloromethyl-2-phenyltriazine (C-4), 2 g of disulfide compound A, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5 -Trimethylhexane (C-5) 170
g, tetrachlorophthalic acid (C-7) 5 g, phthalazine (C-
6) 15 g, the amount of the compound shown in Table 30 in the amount shown in Table 30, Megafax F-176P (fluorinated surfactant manufactured by Dainippon Ink and Chemicals, Inc.) 1.1 g, 2-butanone 590 g, methyl isobutyl ketone 10 g were added with stirring.

(Preparation of Coating Solution A for Emulsion Surface Protective Layer) CAB171-1
5S (Cellulose acetate butyrate manufactured by Eastman Chemical Co., Ltd.)
75 g, 4-methylphthalic acid (C-8) 5.7 g, tetrachlorophthalic anhydride (C-9) 1.5 g, tribromomethylsulfonylbenzene (C-12) 8 g, 2-tribromomethylsulfonylbenzothiazole (C -10) 6g, phthalazone (C-11) 3
g, 0.3 g of Megafax F-176P, Sildex H31 (Dokai Chemical Co., Ltd., spherical silica average size 3 μm) 2 g, sumidur N
3500 (polyisocyanate manufactured by Sumitomo Bayer Urethane Co.) 6 g
Was dissolved in 3070 g of 2-butanone and 30 g of ethyl acetate.

(Preparation of support having back surface) 6 g of polyvinyl butyral (Denka Butyral # 4000-2, manufactured by Denki Kagaku Kogyo KK), Sildex H121 (average size of spherical silica 12 μm, manufactured by Dokai Chemical Co., Ltd.) 0.2 g, Sildex H51 (Tokai Chemical Co., Ltd., spherical silica average size 5 μm) 0.2 g, 0.1 g
Of Megafax F-176P was added to 64 g of 2-propanol with stirring, dissolved and mixed. In addition, 210mg
Of dye A and 210 mg of dye B in 10 g of methanol and 20 g of acetone
Mixed solution and 3-isocyanatomethyl-3,5,5
-0.8 g of trimethylhexyl isocyanate in ethyl acetate 6
A solution dissolved in g was added to prepare a coating solution.

A coating solution for the back side was applied to a polyethylene terephthalate film having a moisture-proof undercoat containing vinylidene chloride on both sides so as to have an optical density of 780 nm of 0.7.

After the emulsion layer coating solution was coated on the support prepared as described above so that the silver content was 2 g / m ² , the emulsion surface protective layer coating solution was dried on the emulsion surface to a dry thickness of 5 μm. To prepare a sample of a heat-developable recording material.

(Exposure, Development) Exposure to xenon flash light with a light emission time of 10 ^-4 sec through a step wedge through an interference filter having a peak at 780 nm, and
After processing (developing) at 25 ° C. for 25 seconds, the density of the obtained image was measured to obtain a characteristic curve.

(Evaluation of High Contrast Property) The gradient of a straight line connecting the points of density 0.3 and 3.0 was shown as gradation gamma. It is preferably 15 or more.

(Evaluation of Storage Property) In order to estimate a change in photographic properties due to storage for a long time, a sample was subjected to 50 ° C. and 50% RH.
Under the condition of 5 days, the sensitivity fluctuation was measured.
The sensitivity was evaluated by a logarithmic value of an exposure amount giving a density 1.5 higher than Dmin. Sensitivity change (ΔS) = sensitivity (sample aged at 50 ° C., 50% for 5 days) −sensitivity (new sample) The closer the value is to 0, the better the performance. The results are shown in Table 30.

[0234]

[Table 30]

(Results) By using the compound of the present invention, a heat-developable recording material satisfying ultra-high contrast property and storage stability could be obtained. The sample of the present invention had sufficiently high sensitivity and Dmax before aging (new).

Example 2 (Preparation of Silver Halide Particles B) After dissolving 22 g of phthalated gelatin and 30 mg of potassium bromide in 700 ml of water and adjusting the pH to 5.0 at a temperature of 40 ° C., an aqueous solution containing 18.6 g of silver nitrate 159m
l and an aqueous solution containing potassium bromide were added over 10 minutes by the control double jet method while maintaining the pAg at 7.7.
An aqueous solution containing 8 × 10 ⁻⁶ mol / L of K ₃ [IrCl ₆ ] ^3- and 1 mol / L of potassium bromide was added over 30 minutes by the control double jet method while maintaining the pAg at 7.7.
Thereafter, the pH was adjusted to 5.9 and pAg 8.0.

The obtained particles had an average particle size of 0.07 μm.
m, a cubic grain having a projection area diameter variation coefficient of 8% and a (100) area ratio of 86%.

The above silver halide grains B were heated to a temperature of 60 ° C., and 8.5 × 10 ⁻⁵ mol of sodium thiosulfate and 1.1 × 10 ⁻⁵ mol of 2,3,4,5, 6-Pentafluorophenyldiphenylsulfin selenide, 2 × 10 ^-6 mol of tellurium compound 1, 3.3 × 10 ^-6 mol of chloroauric acid, 2.3 × 10 ^-4 mol of thiocyanic acid were added, and the mixture was aged for 120 minutes. . Thereafter, the temperature was raised to 50 ° C., 8 × 10 ^-4 mol of sensitizing dye C was added with stirring, and further 3.5 × 10 ^-2 mol of potassium iodide was added, and the mixture was stirred for 30 minutes. After quenching, the preparation of silver halide grains was completed.

(Preparation of Silver Crystalline Dispersion of Organic Acid) Behenic Acid
40 g, stearic acid 7.3 g and distilled water 500 ml were mixed at 90 ° C. for 15 minutes, and 1N-NaOH aqueous solution 187 ml was added over 15 minutes with vigorous stirring, 1N-nitric acid aqueous solution 61 ml was added, and the temperature was lowered to 50 ° C. . Next, add 124 ml of 1N silver nitrate aqueous solution and leave
Stir for 30 minutes. Then, the solid content was filtered by suction filtration,
The solid content was washed with water until the conductivity of the filtrate reached 30 μS / cm. The solid content thus obtained was handled as a wet cake without drying, and 12 g of polyvinyl alcohol and 150 ml of water were added to a wet cake having a dry solid content of 34.8 g and mixed well to form a slurry. Prepare 840 g of zirconia beads having an average diameter of 0.5 mm, put them in a vessel together with the slurry, disperse them in a dispersing machine (1 / 4G-sand grinder mill: manufactured by IMEX Co., Ltd.) for 5 hours, and obtain a volume-weighted average of 1.5 μm. Of organic acid silver microcrystal dispersion was obtained. Particle size measurements are available from Malvern Instruments Ltd.
Performed by MasterSaizerX.

(Preparation of Material Solid Fine Particle Dispersion) Tetrachlorophthalic acid (C-7), 4-methylphthalic acid (C-8), 1,1-
Bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane (C-5), phthalazine (C-6), tribromomethylsulfonylbenzene (C-12) solid fine particle dispersion Was prepared.

To tetrachlorophthalic acid, 0.81 g of hydroxypropylcellulose and 94.2 ml of water were added, stirred well, and left as a slurry for 10 hours. Thereafter, 100 ml of zirconia beads having an average diameter of 0.5 mm and a slurry were put together in a vessel and dispersed for 5 hours using a dispersing machine of the same type as that used for the preparation of the silver salt of organic acid microcrystals. Was obtained. As for the particle size of the solid fine particles, 70 wt% was 1.0 μm or less.

With respect to other materials, the amount of the dispersant used and the dispersion time were appropriately changed in order to obtain a desired average particle size, and a solid fine particle dispersion was obtained.

(Preparation of Emulsion Layer Coating Solution) Each of the following compositions was added to the previously prepared organic acid silver microcrystal dispersion to prepare an emulsion coating solution. Organic acid silver microcrystal dispersion 1 mol Silver halide particles B 0.05 mol Binder: SBR latex (LACSTAR 3307B manufactured by Dainippon Ink and Chemicals, Inc.) 430 g Material for development: tetrachlorophthalic acid 5 g 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -3,5,5-trimethylhexane 98 g phthalazine 9.2 g tribromomethylphenylsulfone 12 g 4-methylphthalic acid 7 g The compounds described in Table 31 are described in Table 31 amount

Note that LACSTAR 3307B is a latex of a styrene-butadiene copolymer, the average particle size of the dispersed particles is 0.1 to 0.15 μm, and 25% of the polymer is 60%
The equilibrium water content at RH was 0.6 wt%.

(Preparation of Emulsion Protective Layer Coating Solution) The following compositions were added to inert gelatin to prepare an emulsion protective layer coating solution. Inert gelatin 10 g Surfactant A 0.26 g Surfactant B 0.09 g Silica fine particles (average particle size 2.5 μm) 0.9 g 1,2- (bisvinylsulfone acetamide) ethane 0.3 g Water 64 g

(Preparation of Back Surface Coating Solution) The following compositions were added to polyvinyl alcohol to prepare a back surface coating solution. Polyvinyl alcohol 30 g Dye C 5 g Water 250 g Sildex H121 (Dorokai Chemical Co., Ltd., spherical silica average size 12 μm) 1.8 g

The emulsion layer coating solution prepared as described above was coated on a polyethylene terephthalate support at a silver concentration of 1.6 g / m ² . An emulsion layer protective layer coating solution was coated thereon so that the coating amount of gelatin became 1.8 g / m ² .
After drying, apply the coating solution for the back side to 780 on the side opposite to the emulsion layer.
It was applied so that the optical density of nm became 0.7, and a sample was prepared.

(Evaluation of Photographic Performance) Exposure, development, and evaluation were performed in the same manner as in Example 1 using the above samples. The results are shown in Table 31.

[0249]

[Table 31]

(Results) By using the compound of the present invention, a heat-developable recording material satisfying ultra-high contrast property and storage stability could be obtained. The sample of the present invention had sufficiently high sensitivity and Dmax before aging (new).

[0251]

According to the present invention, high Dmax, high sensitivity, high contrast is sufficient, and storage stability is excellent.

Claims (3)

[Claims] 1. A heat-developable recording material having at least one image forming layer, comprising an organic silver salt, a reducing agent and a compound represented by the general formula (I):
A heat-developable recording material comprising a compound represented by the formula: Embedded image [In the general formula (I), R ₁ , R ₂ and R ₃ each independently represent a hydrogen atom or a monovalent substituent, and Z represents an electron-withdrawing group or a silyl group. R ₁ and Z, R ₂ and R ₃ ,
R ₁ and R ₂ and R ₃ and Z may be bonded to each other to form a cyclic structure. At least one of R ₁ , R ₂ , R ₃ and Z is -L _1- (R ₄ -L ₂ ) _n1-
(R ₅ ) has a group represented by n ₂ —X. R ₄ and R ₅ each represent a divalent aliphatic group or an aromatic group, and L ₁ and L ₂ each represent a divalent linking group. n ₁ and n ₂
Each independently represents 0 or 1. X represents a group which promotes adsorption to a silver salt. ] 2. The heat-developable recording material according to claim 1, comprising a hydrazine derivative represented by the general formula (H). Embedded image [In the general formula (H), R ¹ represents a hydrogen atom or a block group, R ² represents an aliphatic group, an aromatic group, or a heterocyclic group, and G ¹ represents —CO—, —COCO—, —C ( =
_{S) -, - SO 2 -} , - SO -, - PO (R 3) - (R 3
It is selected from the same range as the groups defined in R ^1, may be different from R ^1. ) Or iminomethylene group.
A ¹ and A ² each represent a hydrogen atom, an alkylsulfonyl group,
Represents an arylsulfonyl group or an acyl group, at least one of which is a hydrogen atom. m1 is 0 or 1, m
When 1 is 0, R ¹ represents an aliphatic group, an aromatic group or a heterocyclic group. ] 3. The heat-developable recording material according to claim 1, which contains a photosensitive silver halide.