JPH0645261B2 - Diazo thermal recording material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a heat-sensitive recording material, and more particularly to a diazo-meter heat-sensitive recording material that can be fixed.

"Prior Art" As a recording material used in a heat-sensitive recording method, a leuco color-forming heat-sensitive recording material is usually used. However, this heat-sensitive recording material has a drawback that color develops unexpectedly due to severe handling after recording, heating or adhesion of solvents, and the recorded image is stained. As a heat-sensitive recording material without such a defect, research on a diazo-based heat-sensitive recording material has been actively conducted in recent years. For example, JP-A-57-1230
No. 86, Journal of the Institute of Image Electronics Engineers, 11 , 290 (1982), etc., but for recording materials using diazo compounds, coupling components and basic components (including substances that become basic by heat). Thermal recording is performed, and then light irradiation is performed to decompose the unreacted diazo compound and stop the color development. Certainly, according to this method, it is possible to stop (hereinafter, referred to as fixing) the color development of a portion where recording is unnecessary.
However, this recording material also has drawbacks such that pre-coupling gradually progresses during storage and undesired coloring (fog) occurs.

In order to improve these drawbacks, a heat-sensitive recording material using a microcapsule containing at least one kind of components involved in a color forming reaction in a core substance and forming a wall by polymerization around the core substance is particularly preferable. It is described in JP-A-59-190886.

"Problems to be solved by the invention" However, even in the heat-sensitive recording material by the microencapsulation method, if the core substance is not sufficiently encapsulated in the microcapsules, pre-coupling occurs to cause fog. Moreover, when an auxiliary solvent is used for the purpose of sufficiently encapsulating the core substance in the microcapsules, there is a manufacturing problem that the auxiliary solvent must be removed later, and further improvement has been demanded.

"Object of the Invention" An object of the present invention is to provide a heat-sensitive recording material having excellent manufacturability, which uses a compound capable of easily dissolving a core substance when forming microcapsules.

"Means for Solving Problems" An object of the present invention is to provide a heat-sensitive recording material having a heat-sensitive recording layer containing microcapsules containing any one of a diazo compound, a coupling component, and a basic compound on a support. This has been achieved by a diazo-based heat-sensitive recording material characterized in that the microcapsules contain optionally substituted diphenyl carbonate.

Among the diphenyl carbonates according to the present invention, preferable compounds are represented by the following general formula (I).

In the above formula, R ₁ or R ₂ each represents a phenyl group which may have a substituent, and preferred substituents for R ₁ and R _{2 in} the above formula are an alkyl group, an aryl group, an alkyloxy group, Examples thereof include an alkylthio group, an aryloxy group, an arylthio group, a halogen atom, a cyano group, an acyl group, a carboxylic acid ester group, and a sulfonic acid ester group.

R ₁ and R ₂ may be the same or different.

1) Diphenyl carbonate 2) 4-isopropylphenyl phenyl carbonate 3) 2-chlorophenyl phenyl carbonate 4) m-ethyl phenyl carbonate 5) p-ethyl Phenyl phenyl carbonate 6) o-methoxy carbonyl phenyl carbonate 7) p- methoxy phenyl phenyl carbonate etc. are mentioned. It goes without saying that the invention is not limited to these examples.

Moreover, these can also be used in combination of 2 or more types.

The diphenyl carbonate according to the present invention is contained as a core substance in the microcapsule, and can coexist with any of the diazo compound, the coupling component or the basic substance, but it is contained in the microcapsule together with the diazo compound. Is particularly preferable.

In the present invention, it is preferable that the coloring layer further contains at least one kind of aromatic ether or ester and at least one kind of alcohols, phenols, sulfonamides, and acid amides to improve raw storage stability and thermochromic property. Is preferable and the decrease in optical density of a recorded image due to long-term storage after thermal recording is reduced.

The aromatic ether is represented by Ar—O—R, and specific examples include 1) 2-benzyloxynaphthalene 2) 1-p-biphenyloxy-2-phenylethane 3) 2-p-chlorobenzyloxynaphthalene 4) 1, 2-diphenoxyethane 5) 1-phenoxy-2-p-chlorophenoxyethane 6) p-biphenyl-β-methoxyethyl ether 7) p-biphenyl-β-cyclohexyloxyethyl ether and the like.

As an ester compound And R ₁ and R ₂ or R ₃ and R ₄ may be the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an acyl group, a halogen atom,
It represents a cyano group, an aryl group, an alkyloxycarbonyl group or an aryloxycarbonyl group. R ₁ and R ₂ may be linked to form a ring.

Of the substituents represented by R, an alkoxy group, an aryloxy group, an alkyl group having 1 to 10 carbon atoms which may be substituted with a halogen atom or an aryl group, or an alkyl group, an alkoxy group, a hydroxy group or a halogen atom. An aryl group having 6 to 12 carbon atoms which may be substituted is particularly preferable.

1) 2-benzoyloxynaphthalene 2) 1,2-bis (β-phenoxyethoxycarbonyl) ethane 3) 1,4-bis (β-phenoxyethoxycarbonyl) butane 4) 1 -P-methylbenzoyloxy-2-p-biphenyloxyethane 5) 1-hydroxy-2-phenoxycarbonylnaphthalene and the like can be mentioned.

Examples of alcohols include the following: R—OH In the above formula, R is an optionally substituted alkyl group,
It may be linear, branched, cyclic or unsaturated and may be a halogen atom, an acyl group, an alkoxy group, a hydroxy group, an aryl group, an aryloxy group, an alkoxycarbonyl group, an acylamino group, a cyano group, a nitro group or an acyloxy. It may be substituted with one or more of the groups.

Specific examples are 1) p-xylenol, 2) m-xylenol, 3) hydroxybenzyl alcohol, 4).
Hydroxyphenethyl alcohol, 5) p-methoxyphenoxyethanol, 6) perhydrobisphenol A, 7) naphthylenediol, 8) methylxylylenediol, 9) methoxyxylylenediol, and the like.

The phenols are represented by Ar-OH, and specifically, 1) p
-T-butylphenol, 2) pt-octylphenol, 3) p-α-cumylphenol, 4) pt-pentylphenol, 5) 2,5-dimethylphenol,
6) 2,4,5-trimethylphenol, 7) 3-methyl-4-isopropylphenol, 8) p-benzylphenol, 9) o-cyclohexylphenol, 10) p
Examples include-(diphenylmethyl) phenol, 11) p-benzyloxyphenol and the like.

Examples of amides include carboxylic acid amides and sulfonic acid amides, and arylcarboxylic acid amides and arylsulfonic acid amides are particularly preferable.

Specific examples of the arylcarboxylic acid include 1) benzamide, 2) ethylbenzamide, 3) isopropylbenzamide, 4) dimethylbenzamide, 5) chlorobenzamide, 6) methoxybenzamide, and the like. As the sulfonic acid amide, 1) ethylbenzenesulfonamide, 2) o-toluenesulfonamide, 3)
and o-methoxybenzenesulfonamide, 4) chlorobenzenesulfonamide, 5) ethoxybenzenesulfonamide, 6) p-toluenesulfonamide, and the like.

The diazo compound used in the present invention has the general formula ArNa ⁺
X ⁻ (in the formula, Ar represents an aromatic moiety, N ₂₊ represents a diazonium group, and X ⁻ represents an acid anion).

It is a compound capable of producing a color by causing a coupling reaction with a coupling component and being decomposed by light.

Specific examples of the aromatic moiety are preferably those represented by the following general formula.

In the formula, Y represents a hydrogen atom, a substituted amino group, an alkoxy group, an aryloxy group, an arylthio group, an alkylthio group or an acylamino group, and R represents a hydrogen atom, an alkyl group, an alkoxy group, an aryloxy group, an arylamino group or , Halogen (I, Br, Cl, F). n represents 1 or 2.

The substituted amino group of Y includes a monoalkylamino group, a dialkylamino group, an arylamino group, a morpholino group,
A piperidino group and a pyrrolidino group are preferred.

Specific examples of the diazonium forming a salt include 4-diazo-1-dimethylaminobenzene, 4-diazo-1-diethylaminobenzene, 4-diazo-1-dipropylaminobenzene, 4-diazo-1-methylbenzylamino. Benzene, 4-diazo-1-dibenzylaminobenzene, 4-diazo-1-ethylhydroxyethylaminobenzene, 4-diazo-1-diethylamino-3-methoxybenzene, 4-diazo-1-dimethylamino-2-methyl Benzene, 4-diazo-1-benzoylamino-
2,5-diethoxybenzene, 4-diazo-1-morpholinobenzene, 4-diazo-1-morpholino-2,5-
Diethoxybenzene, 4-diazo-1-morpholino-
2,5-dibutoxybenzene, 4-diazo-1-anilinobenzene, 4-diazo-1-toluylmercapto-
2,5-diethoxybenzene, 4-diazo-1,4-methoxybenzoylamino-2,5-diethoxybenzene, 4-diazo-1-pyrrolidino-2-etherbenzene and the like can be mentioned.

Specific examples of the acid anion include CnF _{2n + 1} COO ⁻ (n
Is an integer of _{3~9), C m F 2m +} 1 SO 3 - (m is 2-8 _{integer), (C l F 2l +} 1 SO 2) 2 CH - (l 1 to 18 integer), Examples thereof include BF ₄ ⁻ and PF ₆ ⁻ .

Particularly, as the acid anion, those containing a perfluoroalkyl group or a perfluoroalkenyl group, or PF ₆ ⁻ is preferable because it does not increase fog during raw preservation.

Specific examples of the diazo compound (diazonium salt) include the following examples.

The coupling component used in the present invention is one that couples with a diazo compound (diazonium salt) in a basic atmosphere to form a dye, and specific examples thereof include resorcin, fluorocurcine and 2,3-dihydroxynaphthalene-6-sulfonic acid. Sodium, 1-hydroxy-2-
Naphthoic acid morpholinopropylamide, 1,5-dihydroxynaphthalene, 2,3-dihydroxynaphthalene,
2,3-dihydroxy-6-sulfanylnaphthalene,
2-Hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-naphthoic acid anilide, 2-
Hydroxy-3-naphthoic acid-2'-methylanilide,
2-hydroxy-3-naphthoic acid ethanolamide, 2
-Hydroxy-3-naphthoic acid octylamide, 2-hydroxy-3-naphthoic acid-N-dodecyl-oxy-propylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, 1- Phenyl-3-methyl-5-pyrazolone, 1- (2 ', 4', 6'-trichlorophenyl) -3-benzamido-5-pyrazolone, 1- (2 ', 4', 6'-trichlorophenyl) ) −
3-anilino-5-pyrazolone, 1-phenyl-3-phenylacetamido-5-pyrazolone and the like can be mentioned.
Further, by using two or more of these coupling components in combination, an image of any color tone can be obtained.

It is preferable to add a basic substance to the heat-sensitive recording material of the present invention in order to promote color development, but as the basic substance, a poorly water-soluble or water-insoluble basic substance or a substance which generates an alkali by heating is used. Used.

As the basic substance, inorganic and organic ammonium salts, organic amines, amides, urea and thiourea, isothiourea and its derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles and imidazolines. And nitrogen-containing compounds such as triazoles, morpholines, piperidines, amidines, formazines, and pyridines. Specific examples thereof include ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine, allylurea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, 2-benzylimidazole, 4-phenyl. Imidazole, 2-phenyl-4-methyl-imidazole, 2
-Undecyl-imidazoline, 2,4,5-trifuryl-2-imidazoline, 1,2-diphenyl-4,4-dimethyl-2-imidazoline, 2-phenyl-2-imidazoline, 1,2,3-triphenylguanidine , 1, 2
-Ditolylguanidine, 1,2-dicyclohexylguanidine, 1,2,3-tricyclohexylguanidine,
Guanidine trichloroacetate, N, N'-dibenzylpiperazine, 4,4'-dithiomorpholine, morpholinium trichloroacetate, 2-amino-benzothiazole,
There is 2-benzoylhydrazino-benzothiazole.
These basic substances can be used in combination of two or more.

In the present invention, the reactive substance contained in the core substance of the microcapsule is dissolved or dispersed in a water-insoluble organic solvent, and after emulsification, the microcapsule wall is formed by polymerization. Those having a boiling point of 180 ° C. or higher are preferable. Specifically, phosphoric acid ester, phthalic acid ester, other carboxylic acid ester, fatty acid amide, alkylated biphenyl, alkylated terphenyl, chlorinated paraffin, alkylated naphthalene, diarylethane and the like are used. Specific examples include tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, tricyclohexyl phosphate, dibutyl phthalate,
Dioctyl phthalate, dilauryl phthalate, dicyclohexyl phthalate, butyl oleate, diethylene glycol dibenzoate, dioctyl sebacate, dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, dibutyl maleate, isopropyl Biphenyl, isoamylbiphenyl, chlorinated paraffin, diisopropylnaphthalene, 1,1'-ditolylethane, 2,
4-di-syalyaminophenol, N, N-dibutyl-2-butoxy-5-ta-sialyoctylaniline and the like can be mentioned.

Among these, dibutyl phthalate, tricresyl phosphate, diethyl phthalate, dibutyl maleate and the like can be mentioned, but the compound according to the present invention can be used in combination with these solvents or can be used in place of these solvents.

The microcapsules of the present invention are produced by emulsifying a core substance containing a reactive substance and then forming a wall of a polymer substance around the oil droplets. The reactant forming the polymer substance is added inside the oil droplet and / or outside the oil droplet. Specific examples of the polymer substance include polyurethane, polyurea,
Polyamide, polyester, polycarbonate, urea-
Formaldehyde resin, melamine resin, polystyrene,
Examples thereof include styrene methacrylate copolymer, styrene-acrylate copolymer, gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like.

Two or more polymer substances can be used in combination. Preferred polymeric substances are polyurethane, polyurea, polyamide,
Polyester and polycarbonate, more preferably polyurethane and polyurea.

As a method of producing the microcapsule wall of the present invention, the effect is particularly large when the microencapsulation method by polymerizing the reactant from the inside of the oil droplet is used. That is, it is possible to obtain capsules having a uniform particle size within a short period of time, which are preferable as a recording material having excellent raw storability.

This technique and specific examples of compounds are described in the specifications of US Pat. Nos. 3,726,804 and 3,796,669.

For example, when polyurethane is used as a capsule wall material, a polyisocyanate and a second substance (for example, a polyol) which reacts with the polyisocyanate to form a capsule wall are mixed in an oily liquid to be encapsulated, emulsified and dispersed in water, and then the temperature is increased. By rising, a polymer forming reaction is caused at the oil droplet interface to form a microcapsule wall.

In this case, regarding the polyisocyanate to be used and the polyol and polyamine to be reacted therewith, U.S. Pat. Nos. 3,281,383, 3,773,695, and 3,793 are used.
No. 268, Japanese Patent Publication No. 48-40347, and No. 49-241.
59, JP-A-48-80191 and 48-8408.
No. 6, and they can also be used.

Also, tin salt or the like can be used in combination.

In particular, it is preferable to use polyisocyanate as the first wall film-forming substance and polyol as the second wall film-forming substance because of good raw storability. Also, by combining the two, the thermal permeability of the reactive substance can be arbitrarily changed.

Examples of the polyvalent isocyanate that is the first wall film forming substance include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, and naphthalene-1,4. -Diisocyanate, diphenylmethane-
4,4'-diisocyanate, 3,3'-dimethoxy-
4,4'-biphenyl-diisocyanate, 3,3'-
Dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4 '
-Diphenyl propane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate,
Propylene-1,2-diisocyanate, butylene-
1,2-diisocyanate, cyclohexylene-1,2
-Diisocyanates, diisocyanates such as cyclohexylene-1,4-diisocyanate, 4,4 ', 4 "-
Triphenylmethane triisocyanate, toluene-
Triisocyanates such as 2,4,6-triisocyanate, 4,4'-dimethyldiphenylmethane-2,
Tetraisocyanate such as 2 ', 5,5'-tetraisocyanate, adduct of hexamethylene diisocyanate and trimethylolpropane, adduct of 2,4-tolylene diisocyanate and trimethylolpropane, addition of xylylene diisocyanate and trimethylolpropane And an isocyanate prepolymer such as an addition product of tolylene diisocyanate and hexanetriol.

Examples of the polyol that is the second wall film forming substance include aliphatic and aromatic polyhydric alcohols, hydroxypolyesters, and hydroxypolyalkylene ethers. Examples of preferable polyols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanedinol, 1,8. -Octanediol, propylene glycol, 2,3-dihydroxybutane, 1,2-dihydroxybutane, 1,3-
Dihydroxybutane, 2,2-dimethyl-1,3-propanediol, 2,4-pentanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, dihydroxy Cyclohexane, diethylene glycol, 1,2,6
-Trihydroxyhexane, phenylethylene glycol, 1,1,1-trimethylolpropane, hexanetriol, pentaerythritol, glycerin 1,4-
Condensation products of aromatic polyhydric alcohols such as di (2-hydroxyethoxy) benzene and resorcinol dihydroxyethyl ether with alkylene oxides, p-xylylene glycol, m-xylylene glycol, α-α ′.
-Dihydroxy-p-diisopropylbenzene and the like.

Further, 4,4'-dihydroxy-diphenylmethane,
2- (p, p'-dihydroxydiphenylmethyl) benzyl alcohol, an adduct of ethylene oxide with bisphenol A, an adduct of propylene oxide with bisphenol A, and the like. The polyol is preferably used in such a manner that the ratio of the hydroxyl group is 0.02 to 2 mol with respect to 1 mol of the isocyanate group.

When making the microcapsules, a water-soluble polymer can be used, and the water-soluble polymer may be a water-soluble anionic polymer, nonionic polymer, or amphoteric polymer.
As the anionic polymer, natural or synthetic ones can be used, and examples thereof include those having a —COO ⁻ , —SO ₃ ^— group and the like. Specific examples of anionic natural polymers include arabic gum and alginic acid.
Semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, sulfated cellulose and lignin sulfonic acid.

Further, synthetic products include maleic anhydride-based (including hydrolyzed) copolymers, acrylic acid-based (including methacrylic acid-based) polymers and copolymers, vinylbenzenesulfonic acid-based polymers and copolymers, Examples include carboxy-modified polyvinyl alcohol.

Examples of the nonionic polymer include polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose and the like.

Examples of amphoteric compounds include gelatin.

These water-soluble polymers are used as 0.01-10 wt% water-soluble. The particle size of the microcapsules is adjusted to 20 μm or less. Generally, when the particle size exceeds 20 μ, the print image quality tends to deteriorate.

In particular, when heating with a thermal head is performed from the coating layer side, 8 μm or less is preferable in order to avoid pressure fog.

The diazo compound which is the main component used in the present invention, the coupling component and the basic substance which is optionally used are used as any one of them as the core substance of the microcapsules, or two or three of them. Can be used. When two kinds are contained in the core substance of the microcapsules, the same microcapsules or separate microcapsules may be used. Further, when three kinds are contained in the core substance of the microcapsule, the same microcapsule cannot contain three kinds at the same time, but there are various combinations. Other components not contained in the core material of the microcapsules are used in the heat-sensitive layer outside the microcapsules.

When making a microcapsule, it can be made from an emulsion containing 0.2 wt% or more of a component to be microencapsulated.

A diazo compound used in the present invention, a coupling component,
And, if the basic substance used as necessary is contained in the inside of the microcapsule or in the heat-sensitive layer outside the microcapsule, the coupling component is 0.1 to 10 parts by weight with respect to 1 part by weight of the diazo compound. It is preferable to use 0.1 part to 20 parts by weight of the basic substance. The diazo compound is preferably applied in an amount of 0.05 to 5.0 g / m ² .

When the diazo compound, the coupling component and the basic substance used in the present invention are not microencapsulated, it is preferable to use them by solid dispersion with a water-soluble polymer by a sand mill or the like. Preferred water-soluble polymers include water-soluble polymers used when making microcapsules.
At this time, the concentration of the water-soluble polymer is 2 to 30 wt%,
The diazo compound, the coupling component, and the basic substance are added to the water-soluble polymer solution so as to be 5 to 40 wt% each.

The dispersed particle size is preferably 10 μm or less.

To the heat-sensitive recording material of the present invention, a carbamic acid ester compound and an aromatic methoxy compound can be further added for the purpose of further improving the thermochromic property. It is considered that these compounds lower the melting point of the coupling component or the basic substance or improve the heat permeability of the microcapsule wall, and as a result, the practical concentration is increased.

Specific examples of the carbamic acid ester compound include N-phenylcarbamic acid ethyl ester, N-phenylcarbamic acid benzyl ester, N-phenylcarbamic acid phenethyl ester, carbamic acid benzyl ester,
Examples include carbamic acid butyl ester, carbamic acid isopropyl ester, and the like. Specific examples of the aromatic methoxy compound include 2-methoxybenzoic acid, 3,5-dimethoxyphenylacetic acid, 2-methoxynaphthalene, 1,
3,5-trimethoxybenzene, p-benzyloxymethoxybenzene and the like can be mentioned.

These compounds can be used either by forming a microcapsule together with the core substance of the microcapsule or by adding it to the coating liquid of the heat-sensitive recording material and existing outside the microcapsule. Is preferred. In any case, the amount used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, relative to 1 part by weight of the coupling component, but it may be appropriately selected in order to adjust to a desired color density. Good.

The compound according to the present invention is used in an amount of about 50 to 0.01 times, preferably about 10 to 0.2 times, per part by weight of the coupling component.

To the heat-sensitive recording material of the present invention, a free radical generator (a compound capable of generating a free radical upon irradiation with light) used in a photopolymerizable composition or the like for the purpose of reducing yellowing of the background portion after light fixation is added. be able to. As the free radical generator, aromatic ketones (for example, benzophenone, 4,4′-bis (dimethylamino) benzophenone, 4,4′-bis (diethylamino) benzophenone, 4-methoxy-4 ′ (dimethylamino) benzophenone, 4,4'-dimethoxybenzophenone, 4-dimethylaminobenzophenone, 4-
Methoxy, 3,3'-dimethinebenzophenone, 1-hydroxycyclohexylphenyl ketone, 4-dimethylaminoacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propanone- 1
-Acetophenone, benzyl), cyclic aromatic ketones (eg fluorenone, anthrone, xanthone, thioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, acridone, N-ethylacridone, benz Anthrone), quinones (eg benzoquinone, 2, 3, 5
-Trimethyl-6-bromobenzoquinone, 2,6-di-
n-decylbenzoquinone, 1,4-naphthoquinone, 2-
Isopropoxy-1,4-naphthoquinone, 1,2-naphthoquinone, anthraquinone, 2-chloro-anthraquinone, 2-methylanthraquinone, 2-tert-butylanthraquinone, phenanthraquinone), benzoin,
Benzoin ethers (eg, benzoin methyl ether, benzoin ethyl ether, 2,2-dimethoxy-
2-phenylacetophenone, α-methyl benzoin methyl ether), aromatic polycyclic hydrocarbons (for example,
Naphthalene, anthracene, phenanthrene, pyrene), azo compounds (for example, azobisisobutyronitrile, α-azo-1-cyclohexanecarbonitrile, azobisvaleronitrile), organic disulfides (for example, thiuram disulfide), acyloxy Esters (eg, benzyl- (o-ethoxycarbonyl)-
α-monooxime).

The amount added is based on 1 part by weight of the diazonium compound.
The free radical generator is preferably 0.01 to 5 parts by weight. More preferably, it is in the range of 0.1 to 1 part by weight.

By encapsulating the free radical generator together with the diazonium salt as the core substance of the microcapsule, it is possible to reduce the yellow coloring of the background portion after the above-mentioned photofixation.

In the heat-sensitive recording material of the present invention, a polymerizable compound having an ethylenically unsaturated bond (hereinafter referred to as a vinyl monomer) can be used for the purpose of reducing yellow coloring of the background portion after light fixation. A vinyl monomer is a compound having at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in its chemical structure, and is a monomer, prepolymer, that is, dimer, trimer or other The oligomer has a chemical form such as a mixture thereof and a copolymer thereof. Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids with aliphatic polyhydric alcohol compounds, and amides of unsaturated carboxylic acids with aliphatic polyhydric amine compounds.

Vinyl monomer is 0.2 with respect to 1 part by weight of diazo compound.
Used in a proportion of up to 20 parts by weight. The proportion is preferably 1 to 10 parts by weight.

The vinyl monomer is used by containing it in the core material of the microcapsule together with the diazo compound. At this time, part or all of the organic solvent used as the solvent (or dispersion medium) of the core material can be replaced with the vinyl monomer. It need not be added to harden the material.

When the thermosensitive recording material of the present invention contains a diazo compound as a core substance, the coupling reaction deactivator is contained in addition to the microcapsules so that the diazo compound existing in the aqueous phase and the diazo compound in the incomplete capsule are contained. The compound (that is, the diazo compound that is not completely blocked by the capsule wall) reacts with the coupling reaction deactivator, and the diazo compound undergoes the coupling reaction (coloring reaction).
You can lose the ability and prevent fogging.

The coupling reaction deactivator may be any substance that reduces the coloration of the solution in which the diazo compound is dissolved, and the diazo compound may be dissolved in water or an organic solvent and then dissolved in water or an organic solvent. It can be selected by adding the compound and observing the color change of the diazo compound.

Specific examples thereof include hydroquinone, sodium bisulfite, potassium nitrite, hypophosphorous acid, stannous chloride and formalin. Besides this, K. H. Saunders "The Aroma
tic Diazo-Compounds and Their Technical Applicatio
ns ”(London), 1949, pages 105-306.

The coupling reaction quenching agent is preferably one in which the quenching agent itself is less colored and has less side effects. More preferably, it is a water-soluble substance.

The coupling reaction deactivator is used to such an extent that it does not interfere with the thermal coloring reaction of the diazo compound, but it is usually the diazo compound 1
The deactivator is used in the range of 0.01 to 2 mol per mol. It is more preferably used in the range of 0.02 mol to 1 mol.

The coupling reaction quencher of the present invention is a liquid in which microcapsules containing a diazo compound are dispersed after being dissolved in a solvent,
Alternatively, it is used by adding it to a liquid in which a coupling agent or a basic substance is dispersed, or a mixed liquid thereof. Preferably, the quenching agent is used as an aqueous solution.

The heat-sensitive recording material of the present invention contains silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide, for the purpose of preventing sticking to the thermal head and improving the writability.
Pigments such as calcium carbonate and fine powders such as styrene beads and urea-melamine resin can be used.

Similarly, metal soaps can be used to prevent sticking. The usage of these is 0.2
~ 7 g / m ² .

Further, in the heat-sensitive recording material of the present invention, a heat-melting substance can be used to increase the heat-recording density. The heat-melting substance is a substance that is solid at room temperature and has a melting point of 50 to 150 ° C. that melts when heated by a thermal head, and is a substance that dissolves a diazo compound, a coupling component or a basic substance. The heat-fusible substance is dispersed in the form of particles having a particle size of 0.1 to 10 μm and used in an amount of 0.2 to 7 g / m ² of solid content. Specific examples of the heat-fusible substance include N-substituted fatty acid amides, ketone compounds, urea compounds, esters and the like.

The heat-sensitive recording material of the present invention can be coated with a suitable binder.

As the binder, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, arabic rubber, gelatin, polyvinyl pyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic ester, ethylene-vinyl acetate copolymer Various emulsions of polymers can be used. The amount used is a solid content of 0.5 to 5 g / m ² .

In the present invention, in addition to the above materials, citric acid as an acid stabilizer,
Tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid can be added.

The heat-sensitive recording material of the present invention comprises a diazo compound, a coupling component, a main component of a coating solution containing a basic substance and other additives, bar coating on a support such as paper or a synthetic resin film, and a blade. Solid content of 2.5 to 2.5 after coating and drying by coating methods such as coating, air knife coating, gravure coating, roll coating coating, spray coating, and dip coating.
A heat-sensitive layer of 25 g / m ² is provided. As another method, the main component of the coupling component, the basic substance and other additives are added as the core substance of the microcapsules, or they are dispersed in the solid form, or they are dissolved as an aqueous solution and mixed to prepare a coating liquid. Or by coating on a support and drying to obtain a precoat layer having a solid content of ² to 10 g / m ² , and further adding a diazo compound as a main component and other additives as a core substance of the microcapsule thereon, Alternatively, it is also possible to form a laminated type in which a coating liquid prepared by dispersing solid or dissolving as an aqueous solution and then mixing is applied and dried to provide a coating layer having a solid content of 1 to 15 g / m ² . The laminated type heat-sensitive recording material may be formed by laminating the layers in the reverse order, and the coating method may be sequential coating or simultaneous coating of the layers. This laminated-type heat-sensitive recording material is particularly excellent in long-term storability.

It is also possible to apply a heat-sensitive layer after providing an intermediate layer described in Japanese Patent Application No. 177669/1984 on the support.

The paper used for the support is heat extracted pH 6 sized with a neutral sizing agent such as alkyl ketene dimer.
~ 9 neutral paper (as described in JP-A-55-14281)
Is advantageous in terms of storage stability over time.

Further, in order to prevent the coating liquid from penetrating into the paper and to improve the contact between the recording paper head and the thermosensitive recording layer, JP-A-57-116 is used.
687 Moreover, paper having a smoothness of 90 seconds or more is advantageous.

Paper having an optical surface roughness of 8 .mu.m or less and a thickness of 40 to 75 .mu.m described in JP-A-58-136492,
Paper having a density of 0.9 g / cm ³ or less and an optical contact ratio of 15% or more, as described in JP-A No. 8-69091, JP-A-58-6909.
Canadian standard water degree described in No. 7 (JIS P8121)
Paper made from pulp beaten to 400 cc or more with a coating liquid to prevent penetration of the coating liquid, the glossy surface of the base paper made by the Yankee machine described in JP-A-58-65695 is used as the coating surface, and the color density and Papers having improved resolving power, such as those described in JP-A-59-35985, in which base paper is subjected to corona discharge treatment to improve coating suitability, and the like are also used in the present invention and give good results. In addition to these, any of the supports generally used in the field of heat-sensitive recording paper can be used as the support of the present invention.

The heat-sensitive recording material of the present invention can be used as printer paper for facsimiles and electronic calculators that require high-speed recording, and can be fixed by exposing after exposure to heat and decomposing unreacted diazo compounds. . In addition to this, it can also be used as a heat-developing copying paper.

"Examples" Examples will be shown below, but the present invention is not limited thereto. In addition, "part" indicating the addition amount represents "part by weight".

"Examples of the invention" Example 1 3.45 parts of the following diazo compound and (3: 1) adduct 1 of trimethylolpropane with xylylene diisocyanate 1
8 parts and 10 parts of trimethylolpropane were added to a mixed solvent of 6 parts of diphenyl carbonate and 5 parts of ethyl acetate to obtain a transparent solution which was heated and dissolved. A solution of this diazo compound,
5.2 parts of polyvinyl alcohol was mixed with an aqueous solution in which 58 parts of water was mixed, and the mixture was emulsified and dispersed at 20 ° C. to obtain an emulsion having an average particle size of 2.5 μ. 100 parts of water was added to the obtained emulsion, and the mixture was heated to 60 ° C. with stirring, and after 2 hours, a capsule liquid containing a diazo compound as a core substance was obtained.

(Diazo compound) Next, 10 parts of 2-hydroxy-3-naphthoic acid anilide and 10 parts of triphenylguanidine were added to 100 parts of a 5% aqueous solution of polyvinyl alcohol and dispersed in a sand mill for about 24 hours to obtain a coupling component having an average particle size of 3 μm and triphenylguanidine. A dispersion of

Further, 20 parts of p-benzyloxyphenol was added to 100 parts of a 4% polyvinyl alcohol aqueous solution and 100 parts of water, and the mixture was dispersed for 2 hours with a paint shaker to obtain a dispersion liquid having an average particle diameter of 3 μm.

Capsule liquid 5 of diazo compound obtained as described above
A coupling solution, 24 parts of a dispersion of triphenylguanidine and 28 parts of a dispersion of p-benzyloxyphenol were added to 0 parts to prepare a coating solution. This coating solution was applied to a smooth high-quality paper (50 g / m) using a coating bar so that the dry weight was 10 g / m ² , and dried at 25 ° C. for 30 minutes,
A heat sensitive material was obtained.

Example 2 A thermosensitive recording material was obtained in the same manner as in Example 1, except that the diphenyl carbonate of Example 1 was replaced with 4-ethylphenylphenyl carbonate. The solution of diazo compound was transparent.

Example 3 A thermosensitive recording material was obtained in the same manner as in Example 1 except that the diphenyl carbonate of Example 1 was changed to 4-methoxyphenylphenyl carbonate. The solution of diazo compound was transparent.

Example 4 A thermosensitive recording material was obtained in the same manner as in Example 1 except that the diphenyl carbonate of Example 1 was replaced with 2-methoxycarbonylphenylphenyl carbonate. The solution of diazo compound was transparent.

Comparative Example 1 The difuel carbonate of Example 1 was changed to tricresyl phosphate. However, the desired heat-sensitive recording material could not be obtained because the diazo compound was not completely dissolved and became cloudy.

Comparative Example 2 A thermosensitive recording material was obtained in the same manner as in Example 1 except that 18 parts of methine chloride was further added as a cosolvent to the tricresyl phosphate used in Comparative Example 1. The diazo compound solution became uniformly transparent. However, the odor of methylene chloride is strong during the reaction for forming capsules, and since it volatilizes into the air, a closed reaction tank equipped with a recovery device is required.

The fog on the background portion of the obtained raw sample of the thermosensitive recording paper was 0.10 to 0. 0 in each of Examples 1 to 4 and Comparative Example 2.
It was 12, which was satisfactory.

Claims (1)

[Claims] 1. A thermosensitive recording material having a thermosensitive recording layer containing a microcapsule containing any one of a diazo compound, a coupling component and a basic compound on a support, wherein the microcapsules may be substituted. A diazo heat-sensitive recording material containing an enyl carbonate.