JP2001162946A - Photosensitive and heat sensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive and heat sensitive recording material excellent in green preservability, with which a high coloring density is obtained, the lowerings of an image density and of the whiteness of an non-image part (or a ground part) are small even under high temperature environment and an image with a high contrast can be stably formed. SOLUTION: In this photosensitive and heat sensitive recording material having a photosensitive and heat sensitive recording layer including a diazonium salt and a coupler on a support, at least one kind of the diazonium salt is a compound represented by general formula, wherein R1 is a secondary or tertiary alkyl group, R2 and R3 are alkyl groups or allyl groups, n is an integer from 1 through 4 and X- is a negative ion. In preferable embodiments, R1 is a 3 to 12C secondary or tertiary alkyl group, R2 and R3 are 1 to 10C alkyl groups or 6 to 10C allyl groups and X- is a PF6- or a BF4-.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light and heat sensitive recording material having a diazonium salt and a coupler as a color forming component, and more particularly, to a light and heat sensitive recording material capable of obtaining a high color density, forming a high contrast and robust image. About.

[0002]

2. Description of the Related Art Various methods for synthesizing azo dye compounds have been known for a long time.
(Maruzen Co., Ltd., Vol. 14-III, pp. 1516-153
As described in 4), there are synthesis by oxidation reaction, synthesis by reduction reaction, synthesis by substitution reaction, synthesis by addition reaction, synthesis by condensation reaction, and other synthesis methods. However, widely used as an industrial production method of azo dye compounds, in view of availability of raw materials, cost, yield, etc., an azo coupling reaction between a diazonium salt and a coupler such as aniline or a phenol is performed. In most cases, there is a risk that the explosion of the diazonium salt may occur. Therefore, the development of a stable diazonium salt having a low risk of explosion has been conventionally demanded.

On the other hand, some skeletons have been proposed as diazonium salt compounds which can be photodecomposed with a light source having a wavelength longer than 400 nm. For example, "Photosen
situ Diazo Compounds an
d their uses ”(1964 the Fo
cal Press London and New
York, p. 57-86), "J. Inf. Rec.
Mater "(1990, 5, p. 383-395). However, these compounds have problems such as a low photodecomposition rate or low stability, and are further applied to a light fixing type thermosensitive recording material (photosensitive thermosensitive recording material) as described later. Improvement was desired.

A diazonium salt is generally a compound having a very high chemical activity, and easily reacts with a compound having a phenol derivative or an active methylene group, so-called a coupler, to form an azo dye and has photosensitivity. Decomposes by light irradiation and loses its activity. Therefore, diazonium salts have been used for a long time as optical recording materials represented by diazo copy ("Photographic Engineering Fundamentals-Non-Silver Salt Photography-" edited by The Photographic Society of Japan, Corona Co. (1982).
p. 89-117, p. 182-201). Furthermore, utilizing the property of decomposing by light and losing activity, it has recently been applied to recording materials that require fixing of images, and a typical example is recording with a recording layer containing a diazonium salt and a coupler. Heat the material according to the image signal
A photo-fixing type heat-sensitive recording material has been proposed in which a reaction is performed, an image is formed, and an image is fixed by irradiation with light (Koji Sato et al., Journal of the Institute of Image Electronics Engineers of Japan, Vol. 11, No. 4 (1982)).
p. 290-296).

However, in these recording materials using a diazonium salt as a color-forming component, the chemical activity of the diazonium salt is extremely high, and even in a dark place, the diazonium salt gradually decomposes and loses its reactivity. Therefore, there was a disadvantage that the shelf life as a recording material was short. In addition, there is a disadvantage that the residual diazonium salt compound is decomposed at the background portion, which is a non-image portion, at the time of light fixing, and the non-image portion is colored due to generation of a colored decomposition product (stain). Furthermore, even in the completed image after fixing, the non-image portion has a weak light resistance, and there is a drawback that coloring is increased when the image is left for a long time under sunlight or a fluorescent lamp.

Various methods have been proposed as means for improving the instability of such diazonium salts. One of the most effective means is to encapsulate a diazonium salt in microcapsules. Microencapsulation of the diazonium salt isolates the diazonium salt from substances that promote decomposition, such as water and bases, so that its decomposition is significantly suppressed and the shelf life of the recording material using it is dramatically improved. (Masamasa Usami et al., "Journal of the Electrographic Society of Japan," Vol. 26, No. 2, (1987) pp. 115-125).

As a general method for encapsulating a diazonium salt in microcapsules, a diazonium salt is dissolved in a hydrophobic solvent (oil phase), and this is added to an aqueous solution (water phase) in which a water-soluble polymer is dissolved. While emulsifying and dispersing with a homogenizer or the like, the monomer or prepolymer serving as the wall material of the microcapsules is added to either the oil phase side or the aqueous phase side, or both, so that the oil phase and the aqueous phase Is a method in which a polymerization reaction is caused at the interface of the polymer or a polymer is precipitated to form a wall made of a polymer compound to form microcapsules. Such a method
For example, it is described in detail in "Microcapsule" (Asashi Kondo, published by Nikkan Kogyo Shimbunsha, 1970), "Microcapsule" (Tamotsu Kondo et al., Published by Sankyo Publishing, 1977) and the like.

[0008] As the capsule wall of the microcapsule to be formed, various materials such as cross-linked gelatin, alginate, celluloses, urea resin, urethane resin, melamine resin and nylon resin can be used. In particular, in the case of a microcapsule having a glass transition temperature such as a urea resin or urethane resin and having a wall whose glass transition temperature is slightly higher than room temperature, at room temperature the capsule wall shows a material non-permeability, Since it shows a substance permeability above the glass transition temperature, it is called a thermoresponsive microcapsule, and it can be said that it is very useful for a thermosensitive recording material.

That is, a heat-sensitive recording material or a heat-sensitive heat-sensitive material in which a thermoresponsive microcapsule containing a diazonium salt on a support and a (photosensitive) heat-sensitive recording layer containing a coupler as a main color-forming component outside the capsule are provided. In the recording material, the diazonium salt can be stably retained for a long period of time, and at the same time, a colored image can be easily formed by heating, and the formed image can be fixed by further irradiating light. The microencapsulation of the diazonium salt makes it possible to dramatically improve the stability as a recording material.

As described above, although the stability as a heat-sensitive recording material (light-sensitive heat-sensitive recording material) is remarkably improved, the instability caused by the diazonium salt itself is not completely suppressed. It has not yet been possible to obtain sufficient long-term storage properties of heat-sensitive recording materials and the like. In addition, even after printing and fixing, if exposed to a light source for a long period of time, the photodegradation product of the diazonium salt causes a photodecomposition reaction, and the coloring stain increases with the reaction, resulting in a non-image after photofixation. There is also a problem that the whiteness of the portion (background portion) is reduced and the contrast with the colored portion is also reduced.

Further, it is known that the photodecomposition reaction as described above cannot occur uniformly and various decomposition products are produced depending on the surrounding environment and the like. This results in a product called photolytic stain, which has absorption in the visible region in particular. Here, if the occurrence of this stain is remarkable, the whiteness of the non-image portion (background portion) after light fixing is reduced, and the contrast with the color-developed portion is also reduced. As a result, the commercial value of the recording material itself is significantly impaired. Become. However, since the photodecomposition reaction of the diazonium salt is complicated and its product is difficult to identify, it is considered difficult to suppress the photodegradation stain.

[0012] Accordingly, in recent years, researches on the improvement of long-term stabilization caused by photodegradation stain have been actively conducted. For example, Japanese Patent Application Laid-Open No. 8-324129 discloses a microcapsule containing a light-fixing type diazonium salt. By using a specific hydrophobic oil together, a light-fixing type heat-sensitive recording material that has excellent raw storability and also has excellent image storability that does not impair whiteness even if exposed to light for a long time after image formation is obtained. Proposed. Further, Japanese Patent Application No. 9-237233 proposes a non-fixing type heat-sensitive recording material using a novel diazonium salt for the purpose of improving the stability of the diazonium salt itself. That is, a diazonium salt having a maximum light absorption wavelength in a shorter wavelength range than near 350 nm is encapsulated in a microcapsule, and a non-fixing type thermosensitive recording material using the microcapsule generally has a wavelength of 350 nm represented by a fluorescent lamp or the like. Improvements regarding whiteness and image storability of a background portion after image formation under a light source having a wavelength longer than the vicinity have been proposed.

However, depending on the preservation environment, raw preservability,
At present, image storability in a color-developed portion and a background portion (non-image portion) after image recording is not yet sufficient, and further improvement in stability is required at present.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, according to the present invention, a high color density can be obtained, and even in a high temperature environment, a decrease in image density and a decrease in whiteness of a non-image portion (background portion) are small and a high-contrast image can be stably formed. It is an object of the present invention to provide a light and heat sensitive recording material having excellent storage stability.

[0015]

Means for solving the above problems are as follows. That is, <1> in a light and heat sensitive recording material having a light and heat sensitive recording layer containing a diazonium salt and a coupler on a support, at least one of the diazonium salts is a compound represented by the following general formula (1). This is a light and heat sensitive recording material.

[0016]

Embedded image [Wherein, R ¹ represents a secondary or tertiary alkyl group;
R ² and R ³ each independently represent an alkyl group or an aryl group. n represents an integer of 1 to 4. X ^- represents an anion. ]

<2> In the general formula (1), R ¹ is a secondary or tertiary alkyl group having 3 to 12 carbon atoms;
R ^2, R ³ are each an alkyl group or an aryl group having 6 to 10 carbon atoms having 1 to 10 carbon atoms, X ^- is PF ₆ ^- or BF ₄ ^- light and heat sensitive recording material according to <1> is It is. <3> The light and heat sensitive recording material according to <1> or <2>, wherein R ² and R ³ in the general formula (1) are both alkyl groups.

<4> The light and heat sensitive recording material according to any one of <1> to <3>, wherein the diazonium salt is encapsulated in microcapsules. <5> The light and heat sensitive recording material according to <4>, wherein the capsule wall of the microcapsule contains polyurethane and / or polyurea as a component.

<6> The light- and heat-sensitive recording material according to any one of <1> to <5>, wherein at least one of the couplers is a compound represented by the following general formula (2) or a tautomer thereof. It is.

[0020]

Embedded image [In the formula, E ¹ and E ² each independently represent an electron-withdrawing group, and E ¹ and E ² may combine to form a ring. ]

<7> The light and heat sensitive recording material according to any one of <1> to <6>, wherein the light and heat sensitive recording layer contains a basic substance.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The light and heat sensitive recording material of the present invention comprises at least a light and heat sensitive recording layer on a support, and the light and heat sensitive recording layer reacts with a diazonium salt and a diazonium salt as a color-forming component. A compound represented by the following general formula (1) is used as the diazonium salt. In addition, other components such as a basic substance are included as necessary. Hereinafter, the light and heat sensitive recording material of the present invention will be described in detail.

(Diazonium Salt) In the light- and heat-sensitive recording material of the present invention, the light- and heat-sensitive recording layer contains at least one compound represented by the following general formula (1) as a diazonium salt as a color-forming component. Features. That is,
A diazonium salt in which an alkyl group having one or two branched chains is disposed at the position represented by R ¹ in the structure of the general formula (1).

[0024]

Embedded image

R ¹ in the general formula (1) is a secondary or tertiary
A secondary or tertiary alkyl group having 3 to 12 carbon atoms is preferable, and a 2- (4,4-dimethylpentyl) group, a 3-heptyl group, and a 2- (6-methylheptyl) are preferable. The groups, 2-propyl, 2-butyl, and 5-undecyl are particularly preferred.

R ² and R ³ each independently represent an alkyl group or an aryl group. Examples of the alkyl group include an ethyl group, a butyl group, a hexyl group, an octyl group, a decyl group, a benzyl group, a phenoxyethyl group, and a phenylethyl group. Among them, an alkyl group having 1 to 10 carbon atoms is preferable. , N-propyl group, n-hexyl group, 2
-Propyl and 2-methyl-1-propyl are particularly preferred. Examples of the aryl group include a phenyl group,
A 4-methoxyphenyl group, a 4-carbamoylphenyl group, a 2- (N, N-diethylcarbamoyl) phenyl group, and the like. Among them, an aryl group having 6 to 10 carbon atoms is preferable, and a phenyl group and a 4-methoxyphenyl group are preferable. Is particularly preferred.

Further, a compound having a structure in which both R ² and R ³ are an alkyl group is more preferred. R ² and R ³
Is an alkyl group, R ² and R ³ may combine with each other to form a ring structure and form a cyclic group containing a nitrogen atom. Examples of the cyclic group include a pyrrolidino group, a piperidino group, a morpholino group, a 4-octanoylpiperazino group, a 4- (2- (2,4-di-t-amylphenoxy)) butanoylpiperazino group , 4- (2- (n-octyloxy) -5-t-octylphenyl) sulfonylpiperazino group, hexamethyleneimino group, indolino group and the like, among which a pyrrolidino group and a hexamethyleneimino group are preferable.

In the general formula (1), n represents an integer of 1 to 4, and preferably an integer of 1 to 2. Further, the X ^- represents an anion. The anion may be either an inorganic anion or an organic anion. Examples of the inorganic anion include hexafluorophosphate ion (PF ₆ ⁻ ), borofluoride ion (BF ₄ ⁻ ),
Chloride ion, sulfate ion and hydrogen sulfate ion are preferably exemplified. Examples of the organic anion include polyfluoroalkyl sulfonate ion, polyfluoroalkyl carboxylate ion, tetraphenyl borate ion and aromatic carboxylate ion. And aromatic sulfonic acid ions. Among them, hexafluorophosphate ion (PF ₆ ⁻ ) and borofluoride ion (BF ₄ ⁻ ) are preferable.

Hereinafter, specific examples of the diazonium salt represented by the general formula (1) will be shown, but the present invention is not limited thereto.

[0030]

Embedded image

[0031]

Embedded image

[0032]

Embedded image

The diazonium salt represented by the general formula (1) can be produced by a known method. That is,
It can be synthesized by diazotizing the corresponding aniline using sodium nitrite, nitrosylsulfuric acid, isoamyl nitrite or the like in an acidic solvent.

The diazonium salt represented by the general formula (1) may be oily or crystalline, but is preferably in a crystalline state at room temperature in terms of handleability. The diazonium salt may be used alone, two or more kinds may be used in combination, or may be used in combination with an existing diazonium salt.

When the diazonium salt is used in a light and heat sensitive recording layer of a light and heat sensitive recording material, the content thereof is preferably 0.02 to 5 g / m ² , and 0.1 to 4 g in terms of color density. / M ² is more preferred.

For stabilization of the diazonium salt of the present invention, a complex compound may be formed using zinc chloride, cadmium chloride, tin chloride or the like to stabilize the diazonium salt.

As described above, the diazonium salt represented by the general formula (1) having -O (CH ₂ ) _n- (secondary or tertiary alkyl group) at the ortho position of the diazonio group is: A color is formed by the reaction with the coupler described below, and at the same time, a high color density can be obtained.Also, even when placed in a high-temperature environment for a long time, a decrease in whiteness due to generation of colored stains and a decrease in density due to a decrease in the color development reaction are caused. Since it is small and has excellent raw storability, it is very useful as a color-forming component used in a light-fixing type light- and heat-sensitive recording material. Therefore, the photosensitive and heat-sensitive recording material containing the diazonium salt can suppress a decrease in image density and a decrease in whiteness of a background portion even in a high-temperature environment, and can form a high-contrast and robust image.

(Coupler) Next, a coupler (coupling component) usable in the light and heat sensitive recording material of the present invention.
Will be described. As the coupler, any compound can be used as long as it can form a dye by coupling with a diazonium salt in a basic atmosphere and / or a neutral atmosphere. All so-called 4-equivalent couplers for silver halide photographic materials can be used as couplers. These can be selected according to the desired hue. For example, a so-called active methylene compound having a methylene group next to a carbonyl group, a phenol derivative,
There are naphthol derivatives and the like, and specific examples include the following, which are used within a range that meets the purpose of the present invention.

Specific examples of the coupler include, for example,
Resorcin, phloroglucin, 2,3-dihydroxynaphthalene, sodium 2,3-dihydroxynaphthalene-6-sulfonate, morpholinopropylamide 1-hydroxy-2-naphthoate, sodium 2-hydroxy-3-naphthalenesulfonate, 2-hydroxy -3-naphthalenesulfonic acid anilide, 2-hydroxy-3-naphthalenesulfonic acid morpholinopropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2-ethylhexyloxypropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2- Ethylhexylamide, 5-acetamido-1-naphthol, 1-hydroxy-8-acetamidonaphthalene-3,6-disulfonate sodium, 1-hydroxy-8-acetamidonaphthalene-
3,6-disulfonic acid dianilide, 1,5-dihydroxynaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3-naphthoic acid anilide, 5, 5-dimethyl-1,3-cyclohexanedione, 1,3-cyclopentanedione, 5- (2-n-tetradecyloxyphenyl) -1,3-cyclohexanedione, 5-phenyl-4-methoxycarbonyl-1 ,
3-cyclohexanedione, 5- (2,5-di-n-octyloxyphenyl) -1,3-cyclohexanedione,

N, N'-dicyclohexyl barbituric acid, N, N'-di-n-dodecyl barbituric acid, N-
n-octyl-N'-n-otatadecyl barbituric acid, N-phenyl-N '-(2,5-di-n-octyl oxdiphenyl) barbituric acid, N, N'-bis (octadecyloxycarbonyl) Methyl) barbituric acid,
1-phenyl-3-methyl-5-pyrazolone, 1-
(2,4,6-trichlorophenyl) -3-anilino-
5-pyrazolone, 1- (2,4,6-trichlorophenyl) -3-benzamido-5-pyrazolone, 6-hydroxy-4-methyl-3-cyano-1- (2-ethylhexyl) -2-pyridone, 2 , 4-bis- (benzoylacetamido) toluene, 1,3-bis- (pivaloylacetamidomethyl) benzene, benzoylacetonitrile, thenoylacetonitrile, acetoacetanilide,
Benzoylacetanilide, pivaloylacetanilide, 2-chloro-5- (Nn-butylsulfamoyl) -1-bivaloylacetamidobenzene, 1- (2
-Ethylhexyloxypropyl) -3-cyano-4-
Methyl-6-hydroxy-1,2-dihydropyridine-
2-one, 1- (dodecyloxypropyl) -3-acetyl-4-methyl-6-hydroxy-1,2-dihydropyridin-2-one, 1- (4-n-octyloxyphenyl) -3-tert- Butyl-5-aminopyrazole and the like.

For details of the coupler, see JP-A-4-4-2.
01483, JP-A-7-223267, JP-A-7-223
223368, JP-A-7-323660, Japanese Patent Application No. 5
-278608, Japanese Patent Application No. 5-297024, Japanese Patent Application No. 6-18669, Japanese Patent Application No. 6-18670, Japanese Patent Application No. 7
No. 316280, Japanese Patent Application No. 8-027095, Japanese Patent Application No. 8-027096, Japanese Patent Application No. 8-030799, Japanese Patent Application No. 8-12610, Japanese Patent Application No. 8-132394, Japanese Patent Application No. 8-358755. And Japanese Patent Application Nos. 8-358756 and 9-0699990.

Among the above, in the present invention, a compound represented by the following general formula (2) or a tautomer thereof is particularly preferred. Hereinafter, the coupler represented by Formula (2) will be described in detail.

[0043]

Embedded image [In the formula, E ¹ and E ² each independently represent an electron-withdrawing group, and E ¹ and E ² may combine to form a ring. ]

The electron-withdrawing group represented by E ¹ and E ² means a substituent having a positive Hammett σ _p value, which may be the same or different. Acetyl, propionyl, pivaloyl, chloroacetyl, trichloroacetyl, trifluoroacetyl, 1-methylcyclopropylcarbonyl, 1
Acyl groups such as -ethylcyclopropylcarbonyl group, 1-benzylcyclopropylcarbonyl group, benzoyl group, 4-methoxybenzoyl group, and thenoyl group; methoxycarbonyl group, ethoxycarbonyl group, 2-methoxyethoxycarbonyl group, 4-methoxyphenoxy An oxycarbonyl group such as a carbonyl group; a carbamoyl group, N, N-
Dimethylcarbamoyl group, N, N-diethylcarbamoyl group, N-phenylcarbamoyl group, N- [2,4-bis (pentyloxy) phenyl] carbamoyl group, N-
Carbamoyl groups such as [2,4-bis (octyloxy) phenyl] carbamoyl group and morpholinocarbonyl group;
Alkylsulfonyl or arylsulfonyl such as methanesulfonyl, benzenesulfonyl and toluenesulfonyl; phosphono such as diethylphosphono; benzoxazol-2-yl, benzothiazole-2-
Yl group, 3,4-dihydroquinazolin-4-one-2-
Yl group, 3,4-dihydroquinazoline-4-sulfone-
A heterocyclic group such as a 2-yl group; a heterocyclic group; a nitro group; an imino group;

The electron-withdrawing groups represented by E ¹ and E ² may be bonded to each other to form a ring. The ring formed by E ¹ and E ² is preferably a 5- or 6-membered carbocyclic or heterocyclic ring.

Hereinafter, specific examples of the coupler represented by the general formula (2) are shown, but the present invention is not limited thereto. In addition, the tautomers of the couplers shown below can also be mentioned as preferable ones.

[0047]

Embedded image

[0048]

Embedded image

[0049]

Embedded image

[0050]

Embedded image

[0051]

Embedded image

[0052]

Embedded image

[0053]

Embedded image

The tautomers of the above-mentioned couplers are those which exist as isomers of the above-mentioned couplers and which have a structure in which the two are easily changed. The tautomers are also preferable as the coupler used in the above.

<Microencapsulation> In the light- and heat-sensitive recording material of the present invention, a diazonium salt is preferably encapsulated in microcapsules for the purpose of improving the raw preservability before use. The method for forming the microcapsules can be appropriately selected from known methods. As the polymer substance forming the capsule wall of the microcapsule, it is impermeable at room temperature and needs to have a property of being permeable at the time of heating. Preferred are, for example, polyurethane, polyurea, polyamide, polyester, urea / formaldehyde resin, melamine resin, polystyrene, styrene / methacrylate copolymer, styrene / acrylate copolymer, and a mixture thereof.

As a method for forming microcapsules, specifically, an interfacial polymerization method or an internal polymerization method is suitable. For details of the capsule forming method and specific examples of the reactants, see US Pat. Nos. 3,726,804 and 3,795.
No. 6,669 and the like. For example, when polyurea or polyurethane is used as the capsule wall material, a polyisocyanate and a second substance (for example, polyol or polyamine) which reacts with the polyisocyanate to form a capsule wall are mixed in an aqueous medium or an oil medium to be encapsulated. Then, these are emulsified and dispersed in water and then heated to cause a polymer forming reaction at the oil droplet interface to form a microcapsule wall. Note that polyurea can be produced even when the addition of the second substance is omitted.

In the present invention, the polymer substance forming the capsule wall of the microcapsule preferably contains at least one of polyurethane and polyurea as a component.

Next, a method for producing a diazonium salt-containing microcapsule (polyurea / polyurethane wall) will be described. First, a diazonium salt is dissolved or dispersed in a hydrophobic organic solvent serving as a core of a capsule to prepare an oil phase serving as a core of a microcapsule. At this time, a polyvalent isocyanate is further added as a wall material.

In preparing the oil phase, the hydrophobic organic solvent used for forming the core of the microcapsules by dissolving and dispersing the diazonium salt is preferably an organic solvent having a boiling point of 100 to 300 ° C., for example, alkylnaphthalene, Alkyl diphenyl ethane, alkyl diphenyl methane, alkyl biphenyl, alkyl terphenyl, chlorinated paraffin, phosphates, maleates, adipic esters, phthalates, benzoates, carbonates, ethers, Sulfuric esters, sulfonic esters and the like can be mentioned. These are 2
You may mix and use more than one kind.

When the solubility of the diazonium salt to be encapsulated in the above-mentioned organic solvent is poor, a low-boiling solvent having a high solubility for the diazonium salt to be used can be used in combination. For example, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methylene chloride, tetrahydrofuran, acetonitrile, acetone and the like can be mentioned. For this reason, the diazonium salt preferably has an appropriate solubility in a high-boiling hydrophobic organic solvent and a low-boiling solvent, and specifically, has a solubility of 5% or more in the solvent. preferable. The solubility in water is preferably 1% or less.

On the other hand, an aqueous solution in which a water-soluble polymer is dissolved is used for the aqueous phase, and after the above-mentioned oil phase is charged, emulsification and dispersion are carried out by means of a homogenizer or the like. And acts as a dispersion medium for stabilizing the emulsified aqueous solution. Here, in order to more uniformly emulsify and disperse and stabilize, a surfactant may be added to at least one of the oil phase and the aqueous phase. As the surfactant, a known surfactant for emulsification can be used. The addition amount of the surfactant is preferably 0.1 to 5% by weight based on the weight of the oil phase,
0.5 to 2% by weight is more preferred.

The water-soluble polymer used for the aqueous solution of the prepared water-soluble polymer in which the oil phase is dispersed is preferably a water-soluble polymer having a solubility in water of 5% or more at the temperature at which the emulsion is to be emulsified. And modified products thereof, polyacrylamide and its derivatives, ethylene-
Vinyl acetate copolymer, styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyvinylpyrrolidone, ethylene-acrylic acid copolymer, vinyl acetate-acrylic acid copolymer Examples include polymers, carboxymethylcellulose, methylcellulose, casein, gelatin, starch derivatives, gum arabic, sodium alginate and the like.

It is preferable that the water-soluble polymer has no or low reactivity with the isocyanate compound.
For example, those having a reactive amino group in the molecular chain, such as gelatin, are preferably modified beforehand to eliminate the reactivity.

As the polyvalent isocyanate compound,
A compound having a trifunctional or higher isocyanate group is preferable, but a bifunctional isocyanate compound may be used.
Specifically, diisocyanates such as xylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, tolylene diisocyanate and its hydrogenated product, and isophorone diisocyanate are used as main raw materials, and dimers or trimers of these (buret or isocyanate) are used. Nurate), as well as polyfunctional adducts of polyols such as trimethylolpropane and bifunctional isocyanates such as xylylene diisocyanate, and adducts of polyols such as trimethylolpropane and bifunctional isocyanates such as xylylene diisocyanate And a compound in which a high molecular weight compound such as polyether having active hydrogen such as polyethylene oxide is introduced, and a formalin condensate of benzene isocyanate. JP-A-62-21
Compounds described in JP-A-2190, JP-A-4-26189, JP-A-5-317694, Japanese Patent Application No. 8-268721, and the like are preferred.

The amount of the polyvalent isocyanate used is determined so that the microcapsules have an average particle size of 0.3 to 12 μm and a wall thickness of 0.01 to 0.3 μm. The diameter of the dispersed particles is generally about 0.2 to 10 μm. In the emulsified dispersion obtained by adding an oil phase to an aqueous phase, a polyurea isocyanate polymerization reaction occurs at the interface between the oil phase and the aqueous phase to form a polyurea wall.

If a polyol and / or a polyamine is further added to the hydrophobic solvent in the aqueous phase or the oil phase, it can be used as one of the constituents of the microcapsule wall by reacting with the polyvalent isocyanate. . In the above reaction, it is preferable to keep the reaction temperature high or to add an appropriate polymerization catalyst from the viewpoint of increasing the reaction rate. Specific examples of these polyols or polyamines include propylene glycol, glycerin, trimethylolpropane,
Triethanolamine, sorbitol, hexamethylenediamine and the like. When a polyol is added, a polyurethane wall is formed. Details of polyvalent isocyanates, polyols, reaction catalysts, and polyamines for forming a part of the wall material are described in detail in Polygraphs (Polyurethane Handbook, edited by Keiji Iwata, Nikkan Kogyo Shimbun (1987)).

The emulsification can be carried out by appropriately selecting from known emulsifying apparatuses such as a homogenizer, a Manton-Gawley, an ultrasonic disperser, a dissolver and a Keddy mill.
After the emulsification, the emulsion is heated to 30 to 70 ° C. in order to promote the capsule wall forming reaction. During the reaction, in order to prevent aggregation of the capsules, it is necessary to lower the probability of collision between the capsules by adding water or to perform sufficient stirring.

During the reaction, a dispersion for preventing aggregation may be added again. Generation of carbon dioxide gas is observed with the progress of the polymerization reaction, and the end thereof can be regarded as an approximate end point of the capsule wall forming reaction. Usually, by reacting for several hours, a desired diazonium salt-encapsulated microcapsule can be obtained.

Next, the coupler used in the present invention can be used as a solid dispersion with, for example, a sand mill together with a water-soluble polymer, an organic base, and other color-forming auxiliaries. After being dissolved in a high-boiling organic solvent that is hardly soluble or insoluble in water, this is dissolved in a surfactant and / or
Alternatively, it is preferably used as an emulsified dispersion obtained by mixing with a polymer aqueous solution (aqueous phase) containing a water-soluble polymer as a protective colloid and emulsifying with a homogenizer or the like. In this case, if necessary, a low boiling point solvent can be used as a dissolution aid. Further, the coupler and the organic base can be separately emulsified and dispersed, or can be mixed and then dissolved in a high boiling point organic solvent to be emulsified and dispersed. The preferred emulsified dispersion particle size is 1 μm or less.

The amount of the coupler to be used is preferably 0.1 to 30 parts by weight based on 1 part by weight of the diazonium salt.

The high boiling organic solvent used in this case is
For example, it can be appropriately selected from high boiling oils described in JP-A-2-141279. Among them, esters are preferable and tricresyl phosphate is particularly preferable from the viewpoint of the emulsion stability of the emulsified dispersion. It is also possible to use the above oils together or with other oils.

In the above organic solvent, further as a dissolution aid,
An auxiliary solvent having a low boiling point can be added, and examples of the auxiliary solvent include, for example, ethyl acetate, isopropyl acetate, butyl acetate, and methylene chloride. Depending on the case, it is also possible to use only low-boiling auxiliary solvents without high-boiling oils.

Examples of the water-soluble polymer to be contained as a protective colloid in the aqueous phase include known anionic polymers,
It can be appropriately selected from nonionic polymers and amphoteric polymers, and among them, for example, polyvinyl alcohol, gelatin, cellulose derivatives and the like are preferable.

As the surfactant to be contained in the aqueous phase, an anionic or nonionic surfactant which does not cause precipitation or aggregation by acting with the above protective colloid is appropriately selected and used. can do. Examples of the surfactant include sodium alkylbenzene sulfonate, sodium alkyl sulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (for example, polyoxyethylene nonylphenyl ether) and the like.

In the present invention, it is also a preferable embodiment to add a basic substance such as an organic base for the purpose of promoting the coupling reaction between the diazonium salt and the coupler. Examples of the organic base include tertiary amines, piperidines,
Nitrogen-containing compounds such as piperazines, amidines, formamidines, pyridines, guanidines, morpholines and the like, for example, JP-B-52-46806,
JP-A-62-70082, JP-A-57-1697
No. 45, Japanese Patent Application Laid-Open No. 60-94381, Japanese Patent Application Laid-Open
JP-A-7-123086, JP-A-60-49991, JP-B-2-24916, JP-B-2-2847
9, JP-A-60-165288, JP-A-60-165288
Preferred examples include those described in JP-A-7-185430. These may be used alone or in combination of two or more.

Of the above, specifically, N, N'-bis (3-phenoxy-2-hydroxypropyl) piperazine, N, N'-bis [3- (p-methylphenoxy)-
2-hydroxypropyl] piperazine, N, N′-bis [3- (p-methoxyphenoxy) -2-hydroxypropyl] piperazine, N, N′-bis (3-phenylthio-2-hydroxypropyl) piperazine, N, N N'-
Bis [3- (β-naphthoxy) -2-hydroxypropyl] piperazine, N-3- (β-naphthoxy) -2-hydroxypropyl-N′-methylpiperazine, 1,4-
Piperazines such as bis {[3- (N-methylpiperazino) -2-hydroxy] propyloxy) benzene;
[3- (β-naphthoxy) -2-hydroxy] propylmorpholine, 1,4-bis (3-morpholino-2-hydroxy-propyloxy) benzene, 1,8-bis (3
Morpholinos such as -morpholino-2-hydroxy-propyloxy) benzene, piperidines such as N- (3-phenoxy-2-hydroxypropyl) piperidine, N-dodecylpiperidine, triphenylguanidine, tricyclohexylguanidine, dicyclohexylphenylguanidine And the like are preferable.

The amount of the basic substance used is preferably 0.1 to 30 parts by weight based on 1 part by weight of the diazonium salt. If the amount is less than 0.1 part by weight, a sufficient color density may not be obtained. If the amount exceeds 30 parts by weight, decomposition of the diazonium salt may be promoted.

Further, in addition to the above-mentioned basic substance, a coloring aid may be added to the photosensitive and heat-sensitive recording layer for the purpose of accelerating the coloring reaction, that is, rapidly and completely thermally printing with low energy. Here, the coloring aid is a substance that increases the coloring density during heating recording or controls the coloring temperature, such as lowering the melting point of a coupler, a basic substance or a diazonium salt, or the softening point of the capsule wall. The condition is such that a diazonium salt, a basic substance, a coupler, and the like are easily reacted by an action capable of lowering the concentration. Examples of the coloring aid include phenol derivatives, naphthol derivatives, alkoxy-substituted benzenes, alkoxy-substituted naphthalenes, aromatic ethers, thioethers, esters, amides, ureides, urethanes, sulfonamide compounds, and hydroxy compounds.

The coloring aid also includes a heat-meltable substance. The heat-meltable substance is a substance that is solid at room temperature and melts by heating and has a melting point of 50 ° C. to 150 ° C., and is a substance that can dissolve a diazonium salt, a coupler, an organic base, or the like. Specific examples include carboxylic amides, N-substituted carboxylic amides, ketone compounds, urea compounds, esters and the like.

In the light and heat sensitive recording material of the present invention, the light and heat fastness of a thermochromic image is improved, or
For the purpose of reducing the yellowing of the unprinted portion (non-image portion) after fixing by light, it is also preferable to use the following known antioxidants and the like. Regarding the antioxidant, for example, European Patent Publication Nos. 223739 and 3094
Nos. 01, 309402 and 31055
No. 1, No. 310552, No. 559416
No. 3,435,443, JP-A-54-48535, JP-A-62-262047, JP-A-63-113536, and JP-A-63-16335.
No. 1, JP-A-2-262654, JP-A-2-262654
No. 71262, JP-A-3-121449, JP-A-5-61166, JP-A-5-119449, U.S. Pat. No. 4,814,262, U.S. Pat. No. 4,980,275, and the like.

It is also effective to use various known additives already used in heat-sensitive or pressure-sensitive recording materials. Examples of the various additives include, for example, JP-A-60-1
Nos. 07384, 60-107383 and 6
Nos. 0-125470, 60-125471, 60-125472 and 60-28748.
No. 5, JP-A-60-287486, JP-A-60-28
Nos. 7487, 60-287488, 61
JP-160287, JP-A-61-185483,
Nos. 61-211079, 62-146678, 62-146680, and 62-1466
No. 79, 62-282885, 63-0
Nos. 51174, 63-89877, 63
JP-A-88380, JP-A-63-088381, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, and JP-A-63-26759.
No. 4, JP-A-63-182484, and JP-A No. 1-2
JP-A-39282, JP-A-4-291885, JP-A-4-291885
291684, 5-188687, 5
Compounds described in JP-A-188686, JP-A-5-110490, JP-A-5-170361, JP-B-48-043294, JP-A-48-033212 and the like can be mentioned.

Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2 -Dihydroquinoline, 6-ethoxy-1-
Phenyl-2,2.4-trimethyl-1,2,3,4-
Tetrahydroquinoline, 6-ethoxy-1-octyl-
2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, nickel cyclohexanoate, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2- Ethyl hexane, 2
-Methyl-4-methoxy-diphenylamine, 1-methyl-2-phenylindole and the like.

The amount of the antioxidant or various additives is 0.05 to 1 part by weight of the diazonium salt.
It is preferably from 100 to 100 parts by weight, more preferably from 0.2 to 30 parts by weight.

The antioxidant and various additives may be contained in a microcapsule together with a diazonium salt, or may be contained as a solid dispersion together with a coupler, a basic substance and other coloring aids. It may be emulsified and contained together with a suitable emulsifying aid, or may be contained in both forms. Further, the antioxidant or various additives may be used alone or in combination of two or more. Further, it can be contained in a protective layer.

The antioxidant and various additives need not always be added to the same layer. The antioxidant and / or
Or, when using a plurality of various additives in combination, aniline, alkoxybenzenes, binder phenols, hindered amines, hydroquinone derivatives, phosphorus compounds, structurally categorized as sulfur compounds, mutually different structures. These may be combined, or a plurality of the same may be combined.

For the purpose of reducing the yellowing of the background after image recording, a free radical generator (a compound which generates free radicals upon irradiation with light) used in a photopolymerizable composition or the like can be added. Examples of the free radical generator include aromatic ketones, quinones, benzoin, benzoin ethers, azo compounds, organic disulfides, acyl oxime esters, and the like. The amount of the free radical generator is 0.01 to 1 part by weight of the diazonium salt.
5 parts by weight are preferred.

Similarly, for the purpose of reducing yellow coloration, a polymerizable compound having an ethylenically unsaturated bond (hereinafter referred to as “polymerizable compound”)
It is called "vinyl monomer". ) Can also be used. A vinyl monomer is a compound having at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in its chemical structure, and has a chemical form of a monomer or prepolymer. Examples of the vinyl monomer include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohols, and amides of unsaturated carboxylic acids and aliphatic polyamine compounds. The vinyl monomer is used in an amount of 0.2 to 20 parts by weight based on 1 part by weight of the diazonium salt. The free radical generator and the vinyl monomer can be used in a microcapsule together with a diazonium salt.

Further, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid and the like can be added as an acid stabilizer.

The photosensitive and heat-sensitive recording layer is prepared by preparing a coating solution containing a microcapsule containing a diazonium salt represented by the general formula (1), a coupler, and if necessary, a basic substance and other components. The coating solution can be applied on a support such as paper or a synthetic resin film by applying and drying. In the present invention, an embodiment in which the light and heat sensitive recording layer contains a basic substance is preferred.

The coating can be appropriately selected from known coating methods, for example, bar coating, blade coating, air knife coating, gravure coating, roll coating, spray coating, dip coating, curtain coating and the like. Can be The dry coating amount of the light and heat sensitive recording layer after coating and drying is preferably 2.5 to 30 g / m ² .

The constitution of the light and heat sensitive recording layer in the light and heat sensitive recording material of the present invention is not particularly limited. For example, a single layer in which microcapsules, couplers, basic substances and the like are all contained in the same layer is used. It may be an embodiment composed of a single layer, or may be an embodiment of a multi-layer laminate type included in another layer. Also, on the support, Japanese Patent Application No.
After providing the intermediate layer described in the specification of 77669, etc., the photosensitive and heat-sensitive recording layer may be formed by coating. Further, as described later, a full-color color developing mode in which a plurality of single-color and single light- and heat-sensitive recording layers having different hues are laminated.

In the light and heat sensitive recording material of the present invention, each layer such as the light and heat sensitive recording layer, the intermediate layer and the protective layer described below can contain a binder. As the binder, a known water-soluble polymer compound or It can be appropriately selected from latexes and the like. Examples of the water-soluble polymer compound include methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, starch derivatives, casein, gum arabic, gelatin, ethylene-maleic anhydride copolymer,
Styrene-maleic anhydride copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, epichlorohydrin-modified polyamide, isobutylene-maleic salicylic anhydride copolymer, polyacrylic acid, polyacrylamide, etc. and modified products thereof Is mentioned.

Examples of the latex include styrene-butadiene rubber latex, methyl acrylate-
Butadiene rubber latex, vinyl acetate emulsion and the like. Among them, hydroxyethyl cellulose,
Preferred are starch derivatives, gelatin, polyvinyl alcohol derivatives, polyacrylamide derivatives and the like.

The light- and heat-sensitive recording material of the present invention may contain a pigment. The pigment may be any known organic or inorganic pigment, for example, kaolin, calcined kaolin, talc, wax. Stone, diatomaceous earth, calcium carbonate, aluminum hydroxide, magnesium hydroxide, zinc oxide, lithopone, amorphous silica, colloidal silica, calcined stone, silica, magnesium carbonate, titanium oxide, alumina, barium carbonate, barium sulfate, mica , Microballoons, urea-formalin fillers, polyester particles, cellulose fillers and the like.

If necessary, various additives such as known waxes, antistatic agents, defoaming agents, conductive agents, fluorescent dyes, surfactants, ultraviolet absorbers and precursors thereof can be used. .

In the light and heat sensitive recording material of the present invention, if necessary, a protective layer may be provided on the light and heat sensitive recording layer. Two or more protective layers may be laminated as necessary. Materials used for the protective layer include polyvinyl alcohol, carboxy-modified polyvinyl alcohol, vinyl acetate-acrylamide copolymer, silicon-modified polyvinyl alcohol, starch, modified starch, methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose,
Gelatin, gum arabic, casein, styrene-maleic acid copolymer hydrolyzate, styrene-maleic acid copolymer half ester hydrolyzate, isobutylene-maleic anhydride copolymer hydrolyzate, polyacrylamide derivative, polyvinylpyrrolidone And water-soluble polymer compounds such as sodium polystyrene sulfonate and sodium alginate; and latexes such as styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, and vinyl acetate emulsion.

The storage stability can be further improved by crosslinking the water-soluble polymer compound.
The crosslinking agent can be appropriately selected from known crosslinking agents, for example, a water-soluble initial condensate such as N-methylol urea, N-methylol melamine, urea-formalin; Aldehyde compounds; inorganic crosslinking agents such as boric acid and borax; and polyamide epichlorohydrin.

For the protective layer, known pigments, metal soaps, waxes, surfactants and the like can be further used. The coating amount of the protective layer is 0.2 to 5 in a dry coating amount.
preferably ^{g / m 2, 0.5~2g / m} 2 is more preferable. The thickness is preferably 0.2 to 5 μm,
0.5 to 2 μm is more preferable. When a protective layer is provided, a known ultraviolet absorber or a precursor thereof may be contained in the protective layer. The protective layer can be provided by the above-mentioned known coating method as in the case of forming the light and heat sensitive recording layer on the support.

As the support usable in the light- and heat-sensitive recording material of the present invention, any paper support used for ordinary pressure-sensitive paper, heat-sensitive paper, dry or wet diazo copy paper, etc. can be used. For example, acid paper, neutral paper, coated paper, plastic film laminated paper, synthetic paper, and plastic films such as polyethylene terephthalate and polyethylene naphthalate can be used.

A back coat layer may be provided on the support for the purpose of correcting the curl balance or improving the chemical resistance from the back surface. The back coat layer can be provided in the same manner as the protective layer. Furthermore, if necessary, an antihalation layer is provided between the support and the light and heat sensitive recording layer, or on the surface of the support on which the light and heat sensitive recording layer is provided, and a slip layer is formed on the back surface thereof.
An antistatic layer, a pressure-sensitive adhesive layer and the like can be provided. Alternatively, a label may be formed by combining a release paper on the back surface of the support (the surface on the side where the photosensitive and heat-sensitive recording layer is not provided) with an adhesive layer interposed therebetween.

As described above, by using the diazonium salt of the present invention in the light- and heat-sensitive recording layer, a high color-forming density can be obtained, and a decrease in whiteness due to coloring of a non-image portion (background portion) in a high-temperature environment. Can be prevented, and a high-contrast image with a small decrease in color density can be stably obtained. Further, by enclosing the diazonium salt in microcapsules, the long-term stability as a recording material can be further improved.

<Image Forming Method> The image forming using the light and heat sensitive recording material of the present invention may be performed by the following method. That is, for example, by heating and printing the surface of the light and heat sensitive recording material on the side where the light and heat sensitive recording layer is provided by a heating device such as a thermal head, the heating portion of the light and heat sensitive recording layer, A method in which a capsule wall containing polyurea and / or polyurethane is softened and becomes material-permeable, and when a coupler or a basic substance (organic base) outside the capsule enters the microcapsule, an image-like color is formed to form an image. It may be. In this case, after the color is formed, by further irradiating light corresponding to the absorption wavelength of the diazonium salt (light fixing), the diazonium salt causes a decomposition reaction and loses reactivity with the coupler, so that the image can be fixed. . By applying light fixing as described above, unreacted diazonium salt causes a decomposition reaction and loses its activity. Therefore, the density of the formed image fluctuates, and coloring occurs due to generation of stain in the non-image area (background area). That is, a decrease in whiteness and a decrease in image contrast due to the decrease can be suppressed.

Examples of the light source used for the light fixing include various fluorescent lamps, xenon lamps, mercury lamps, and the like. The light emission spectrum of these light sources is almost identical to the absorption spectrum of the diazonium salt in the light and heat sensitive recording material. Is preferable in that fixing can be performed with high efficiency. In particular, in the present invention, the emission center wavelength of the irradiated light is 340 to 380 n
It is particularly preferred to use m light sources.

Further, writing is performed imagewise by light,
It can also be used as a photo-writing heat-developing type thermosensitive recording material which forms an image by heat development. In this case, the printing process
A light source such as a laser is used instead of the above-described heating device.

In the light and heat sensitive recording material of the present invention, a multicolor light and heat sensitive recording material can be formed by laminating a plurality of light and heat recording layers having different coloring hues. Examples of the light and heat sensitive recording layer to be laminated include a light and heat sensitive recording layer containing a photodegradable diazonium salt. The multicolor photosensitive and heat-sensitive recording material is disclosed in JP-A-3-288.
No. 688, No. 4-135787, No. 4-14
No. 4784, No. 4-144785, No. 4-1
Nos. 94842, 4-24747, 4-
247448, 4-340540, 4
-340541, 5-34860, 5
194842, Japanese Patent Application No. 7-316280, Japanese Patent Application No. 10-151007, Japanese Patent Application No. 10-1.
No. 51008, Japanese Patent Application No. Hei 10-187783,
It is described in Japanese Patent Application No. 11-253817.

For example, the layer constitution of the full-color photosensitive / thermosensitive recording material may be constituted as follows. However, the present invention is not limited to this. That is, two layers having different coloring hues, comprising two kinds of diazonium salts having different photosensitive wavelengths and being combined with a coupler capable of reacting with the respective diazonium salts upon heating to form different hues, and being contained in separate layers. A full-color photosensitive / thermosensitive recording material comprising a laminated photosensitive / thermosensitive recording layer (layer B, layer C) and a photosensitive / thermosensitive recording layer (layer A) in which an electron-donating colorless dye and an electron-accepting compound are combined. Alternatively, the photosensitive / thermosensitive recording layer may be a combination of the above two photosensitive / thermosensitive recording layers (B layer and C layer), a diazonium salt having a different photosensitive wavelength, and a coupler which reacts with the diazonium salt when heated to form a color. It may be a full-color light and heat sensitive recording material in which a recording layer (layer A) is laminated.

Specifically, an electron-donating colorless dye and an electron-accepting compound or a compound having a maximum absorption wavelength of 3
A first photosensitive and heat-sensitive recording layer (A layer) containing a diazonium salt shorter than 50 nm and a coupler which reacts with the diazonium salt to form a color when heated, and has a maximum absorption wavelength of 360 nm ± 20.
The second photosensitive and heat-sensitive recording layer (B layer) containing a diazonium salt having a wavelength of 400 nm and a coupler which reacts with the diazonium salt when heated to form a color, a diazonium salt having a maximum absorption wavelength of 400 ± 20 nm, Third light- and heat-sensitive recording layer (C layer) containing a coupler that develops a color upon reaction
May be sequentially laminated. In this case, a full-color image can be recorded by selecting the color hues of the photosensitive and heat-sensitive recording layers so as to be three primary colors, yellow, magenta, and cyan in the subtractive color mixing. As the layer configuration of the full-color recording material, yellow, magenta, and cyan color forming layers may be laminated in any manner.
From the viewpoint of the color reproducibility, it is preferable that yellow, cyan, magenta, or yellow, magenta, and cyan are stacked in this order from the support side.

A recording method in the case of a multicolor light- and heat-sensitive recording material can be performed, for example, as follows.
That is, first, the third light and heat sensitive recording layer (C layer) is heated,
The diazonium salt and the coupler contained in the layer are colored. Next, light of 400 ± 20 nm is irradiated to decompose unreacted diazonium salts contained in the C layer. Next, sufficient heat is applied to the second photosensitive and heat-sensitive recording layer (layer B) to develop color, and the diazonium salt and coupler contained in the layer are colored. At this time, the C layer is also heated strongly, but the diazonium salt has already been decomposed and the color forming ability has been lost, so that no color is formed. After this, 360 ± 20n
m is irradiated to decompose the diazonium salt contained in the B layer. Finally, heat is applied to the first photosensitive and heat-sensitive recording layer (A layer) to develop a color, and the color is developed. Then C
The layers B and B are also heated strongly at the same time, but the diazonium salt has already been decomposed and the color-forming ability has been lost, so that no color is formed. In the light and heat sensitive recording material of the present invention, it is preferable to use a multicolor light and heat recording material as described above.

As described above, the color-forming mechanism of the light- and heat-sensitive recording layer (layer A) directly laminated on the support surface may be a combination of an electron-donating dye and an electron-accepting dye, or a diazonium salt and the diazonium salt. It is not limited to a combination of a salt and a coupler which develops a color when reacted with heat, and develops a color by contacting with a basic compound to form a base, a chelate or a nucleophile to cause a elimination reaction. Any of a coloring system or the like may be used. By providing a light- and heat-sensitive recording layer containing a diazonium salt and a coupler that reacts with the diazonium salt and forms a color on the light- and heat-sensitive recording layer, a multicolor light and heat-sensitive recording material can be formed.

In the case of a multicolor photosensitive / thermosensitive recording material, an intermediate layer may be provided between the photosensitive / thermosensitive recording layers in order to prevent color mixing between the photosensitive / thermosensitive recording layers. The intermediate layer is made of a water-soluble polymer compound such as gelatin, phthalated gelatin, polyvinyl alcohol, and polyvinylpyrrolidone, and may appropriately contain various additives.

When the light- and heat-sensitive recording material of the present invention is a multicolor light- and heat-sensitive recording material having a light-fixing light- and heat-sensitive recording layer on a support, if necessary, a light transmittance control may be further provided as an upper layer. It is desirable to provide a layer or a protective layer, or a light transmittance adjusting layer and a protective layer. The light transmittance adjusting layer is described in JP-A-9-39395 and JP-A-9-39.
396, Japanese Patent Application No. 7-208386, and the like. When a component that functions as a precursor of an ultraviolet absorber is used in the light transmittance adjustment layer, a high light transmittance is required before irradiation with light in a wavelength range necessary for fixing because the component does not function as an ultraviolet absorber. Therefore, when fixing the light-fixing type photosensitive heat-sensitive recording layer, it is possible to sufficiently transmit wavelengths in a region required for fixing and has a high visible light transmittance, which hinders fixing of the photosensitive heat-sensitive recording layer. Never.

On the other hand, the precursor of the ultraviolet absorber is irradiated with light in a wavelength region necessary for photo-fixing of the photo-fixing type photosensitive heat-sensitive recording layer (photo-decomposition of diazonium salt by light irradiation), and then reacted by the light. And act as an ultraviolet absorber. The ultraviolet absorber absorbs most of the light having a wavelength in the ultraviolet region, lowers the transmittance, and improves the light resistance of the light and heat sensitive recording material. However, since there is no absorption of visible light, the transmittance of visible light is not substantially changed. At least one light transmittance adjusting layer can be provided in the light and heat sensitive recording material, and particularly, it is preferably formed between the light and heat sensitive recording layer and the protective layer. Further, the function of the light transmittance adjusting layer may be imparted to the protective layer, and may be shared.

[0113]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. In the examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

(Example 1) <Synthesis of diazonium salt A-1>: Exemplified compound A-1 10 g of 4-di-n-propylamino-2- (3,5,5-trimethylhexyloxy) acetanilide, hydrochloric acid 7
Then, 50 ml of methanol and 50 ml of methanol were mixed, the mixture was heated under reflux for 1 hour, and after cooling, 4.0 ml of an aqueous solution in which 2.0 g of sodium nitrite was dissolved was added dropwise. Thereafter, the mixture was stirred at 0 ° C. for 15 minutes, 6.0 g of potassium hexafluorophosphate was added, and the generated crystals were collected by filtration. The obtained crystals were recrystallized from ethyl acetate-2-propyl alcohol, collected by filtration and dried to obtain a diazonium salt A-1.
Was obtained in an amount of 9.1 g (yield 70%).

The diazonium salt A-1 thus obtained was identified by
^{This was performed by 1} H-NMR (solvent: CDCl ₃ , 300 MHz). The data is shown below. ¹ H-NMR (δ, ppm): 0.91 (s, 9H),
0.93-1.08 (br, 9H), 1.16 (dd,
1H), 1.25 (dd, 1H), 1.71 (br, 6
H), 1.91 (m, 1H), 3.48 (t, 4H),
4.26 (t, 2H), 6.10 (d, 1H), 6.5
4 (dd, 1H), 7.93 (d, 1H) The maximum absorption wavelength λmax in methanol is 369 nm,
The molecular extinction coefficient ε was 3.48 × 10 ⁴ [cm ⁻¹ M ⁻¹ ].

<Preparation of microcapsule solution containing diazonium salt> In 16 parts of ethyl acetate, 3.0 parts of the diazonium salt A-1 obtained above and tricresyl phosphate 1 were added.
2.1 parts and mixed uniformly. Next, 8.8 parts of a capsule wall material (Takenate D-110N, manufactured by Takeda Pharmaceutical Co., Ltd.) was added to and mixed with this mixed liquid to obtain Liquid I. Next, 60 parts of an 8% aqueous solution of phthalated gelatin, water 2
3.5 parts of sodium dodecylbenzenesulfonate
Solution I obtained above was added to a mixed solution of 2.5 parts of a 0% aqueous solution, and the mixture was subjected to 40 ° C. and 100 rpm using a homogenizer.
The mixture was emulsified and dispersed at 00 rpm for 10 minutes.

To the obtained emulsified dispersion, 20 parts of water was added, and the mixture was uniformly mixed. The mixture was microencapsulated at 40 ° C. for 3 hours with stirring to obtain a diazonium salt-containing microcapsule liquid. The average particle size of the microcapsules is 0.
It was 8 to 1.1 μm.

<Preparation of Coupler Emulsion> Ethyl acetate 1
In 0.5 part, 3 parts of a coupler (exemplified compound B-40), 2.8 parts of triphenylguanidine, 0.8 part of tricresyl phosphate, and 0.5 part of diethyl maleate were dissolved.
Solution II was obtained. Next, a 15% aqueous solution of lime-processed gelatin 4
9 parts, 10% of sodium dodecylbenzenesulfonate
9.5 parts of an aqueous solution and 35 parts of water were mixed, and the resulting solution II was added to a mixed solution homogenized at 40 ° C., and the mixture was added at 40 ° C. and 10000 rpm using a homogenizer.
Emulsified and dispersed for 0 minutes. The obtained emulsified dispersion was stirred at 40 ° C. for 2 hours to remove ethyl acetate.
One part was added to obtain a coupler emulsion.

<Preparation of Coating Solution for Light- and Heat-Sensitive Recording Layer> 3.6 parts of a diazonium salt-encapsulated microcapsule solution, 3.3 parts of water
And 10.5 parts of a coupler emulsion were mixed to prepare a coating solution for a light and heat sensitive recording layer.

<Preparation of Coating Solution for Protective Layer> 100 parts of a 6% aqueous solution of itaconic acid-modified polyvinyl alcohol (KL-318; manufactured by Kuraray Co., Ltd.) and epoxy-modified polyamide (FL-71; manufactured by Toho Chemical Co., Ltd.) 30% dispersion 10
And a dispersion of 40% zinc stearate (Hydrin Z; manufactured by Chukyo Yushi Co., Ltd.) was uniformly mixed with the mixed solution to prepare a coating solution for a protective layer.

As a support, a photographic paper support obtained by laminating polyethylene on a high-quality paper was prepared, and a coating solution for a light and heat sensitive recording layer and a coating solution for a protective layer were applied in this order on a photographic paper support with a wire bar. After coating, drying was performed at 50 ° C. to obtain a light and heat sensitive recording material (1) of the present invention. The dry coating amounts of the light and heat sensitive recording layer and the protective layer were 8.0 g /
m ² , 1.6 g / m ² .

<Coloring Test> A thermal head (KST type) manufactured by Kyocera Corporation was used to determine the voltage and pulse width applied to the thermal head so that the recording energy per unit area was 50 mJ / mm ^2, and the light and heat recording was performed. After thermal printing from the protective layer of the material (1) to form an image, ultraviolet light was applied to the entire surface of the protective layer for 12 seconds using an ultraviolet lamp having an emission center wavelength of 365 nm and an output of 40 W.
After the irradiation, the image density and the background density (density of the non-image part) of the color-developed part were measured. The usable range is 1.5 or higher in the density of the color forming portion, and 0.15 or lower in the non-image portion. The measured results are shown in Table 1 below.

<Preservation test> The unprinted photosensitive and heat-sensitive recording material (1) was placed in a thermo-hygrostat at 60 ° C. and 30% RH for 72 hours.
After standing for a period of time, an image was formed by thermal printing in the same manner as in the color development test, and the entire surface was irradiated with ultraviolet light. afterwards,
The image density and the background density (density of the non-image part) of the color-developed part were measured. As for the storability, as compared with the density measured by the color development test, the smaller the change width of the image density and the smaller the value of the background density, the better. The measured results are shown in Table 1 below.
Shown in

<Density Measurement> The density measurement in each of the above tests was performed using a Macbeth densitometer (Macbeth RD-91).
8; manufactured by Macbeth Co., Ltd.), and the density of the colored portion was measured at the C position, and the density of the background portion was measured at the Y position.

(Example 2) The present invention was carried out in the same manner as in Example 1 except that the above-mentioned exemplified compound A-2 (diazonium salt) was used instead of the diazonium salt A-1 used in Example 1. The photosensitive and heat-sensitive recording material (2) was obtained. In addition, the diazonium salt A-2 was obtained in the same manner as in Example 1. Further, using the photosensitive and heat-sensitive recording material (2), a color development test and a storage stability test were performed in the same manner as in Example 1, and the density of the formed image was measured. The measurement results are shown in Table 1 below.

Example 3 The above-mentioned exemplified compound B-35 was used in place of the coupler used in the coupler emulsion of Example 1.
A light and heat sensitive recording material (3) of the present invention was obtained in the same manner as in Example 1 except that (coupler) was used. Further, using the photosensitive and heat-sensitive recording material (3), a color development test and a storage stability test were performed in the same manner as in Example 1, and the density of the formed image was measured. The measurement results are shown in Table 1 below.

(Example 4) The diazonium salt A-1 used in Example 1 was replaced with the exemplified compound A-3 (diazonium salt) described above, and the coupler used in the coupler emulsion of Example 1 was replaced with A light- and heat-sensitive recording material (4) of the present invention was obtained in the same manner as in Example 1, except that Example Compound B-35 (coupler) described above was used instead. In addition, the diazonium salt A-3 is
Obtained in the same manner as in Example 1. Further, using the photosensitive and heat-sensitive recording material (4), a color development test and a storage stability test were performed in the same manner as in Example 1, and the density of the formed image was measured. The measurement results are shown in Table 1 below.

Comparative Example 1 A light and heat sensitive recording material (5) was prepared in the same manner as in Example 1 except that the following diazonium salt C-1 was used in place of the diazonium salt A-1 used in Example 1. Obtained. Further, using a light and heat sensitive recording material (5),
In the same manner as in Example 1, a color development test and a storage stability test were performed, and the density of the formed image was measured. The measurement results are shown in Table 1 below.

Comparative Example 2 A light and heat sensitive recording material (6) was prepared in the same manner as in Example 2 except that the following diazonium salt C-2 was used in place of the diazonium salt A-1 used in Example 1. Obtained. Further, using a light and heat sensitive recording material (6),
In the same manner as in Example 1, a color development test and a storage stability test were performed, and the density of the formed image was measured. The measurement results are shown in Table 1 below.

Comparative Example 3 A light and heat sensitive recording material (7) was prepared in the same manner as in Example 1 except that the following diazonium salt C-3 was used in place of the diazonium salt A-1 used in Example 1. Obtained. Further, using a light and heat sensitive recording material (7),
In the same manner as in Example 1, a color development test and a storage stability test were performed, and the density of the formed image was measured. The measurement results are shown in Table 1 below.

[0131]

Embedded image

[0132]

[Table 1]

From the results shown in Table 1, the above-mentioned general formula (1)
In the light- and heat-sensitive recording materials (1) to (4) of the present invention containing a diazonium salt represented by the following formula as a color-forming component, sufficient color density and whiteness of the background can be obtained. Even when stored for a long time underneath, a robust image with little reduction in image density of the image portion and whiteness of the background portion could be formed. On the other hand, the light and heat sensitive recording materials (5) to which the diazonium salt specified in the present invention was not used were used.
In (7), the background density was also increased by the image formation in the color development test, and furthermore, when each photosensitive and heat-sensitive recording material was stored for a long time in a high-temperature environment, the density fluctuation range of the image density and the background density was reduced. Large, robust images could not be obtained. In addition, the contrast also decreased as the whiteness of the non-image portion decreased.

[0134]

According to the present invention, a high color density can be obtained, and even in a high temperature environment, a decrease in image density and a decrease in whiteness of a non-image portion (background portion) are small and a high-contrast image can be stably formed. A photosensitive and heat-sensitive recording material which can be formed and has excellent raw preservability can be provided.

Claims (7)

[Claims] 1. A light and heat sensitive recording material having a light and heat sensitive recording layer containing a diazonium salt and a coupler on a support, wherein at least one of the diazonium salts is a compound represented by the following general formula (1). A light- and heat-sensitive recording material, characterized in that: Embedded image [Wherein, R ¹ represents a secondary or tertiary alkyl group;
R ² and R ³ each independently represent an alkyl group or an aryl group. n represents an integer of 1 to 4. X ^- represents an anion. ] 2. In the general formula (1), R ¹ has 3 carbon atoms.
To 12 secondary or tertiary alkyl groups, wherein R ² and R ³ are each an alkyl group having 1 to 10 carbon atoms or 6-1.
0 of an aryl group, X ^- is PF ₆ ^- or BF ₄ ^- light and heat sensitive recording material according to claim 1 is. 3. The light- and heat-sensitive recording material according to claim 1, wherein R ² and R ³ in the general formula (1) are both alkyl groups. 4. The light and heat sensitive recording material according to claim 1, wherein the diazonium salt is encapsulated in a microcapsule. 5. The light and heat sensitive recording material according to claim 4, wherein the capsule wall of the microcapsule contains polyurethane and / or polyurea as a component. 6. The light- and heat-sensitive recording material according to claim 1, wherein at least one of the couplers is a compound represented by the following general formula (2) or a tautomer thereof. Embedded image [In the formula, E ¹ and E ² each independently represent an electron-withdrawing group, and E ¹ and E ² may combine to form a ring. ] 7. The light and heat sensitive recording material according to claim 1, wherein the light and heat sensitive recording layer contains a basic substance.