JPS62146679A - Thermal recording material - Google Patents

Abstract

PURPOSE:To improve the light fastness and heat resistance of a thermally developed color image after fixing, by incorporating least one specific compound in thermal layer. CONSTITUTION:In a thermal recording material wherein a thermal layer containing a diazonium salt and a coupler is provided on a support, said thermal layer contains at least one compound represented by formula [I]. When the diazonium salt or the coupler was microencapsulated, said compound represented by the formula [I] can be contained in a microcapsule or added inside and outside said microcapsule. When the compound is added in a fine particulate sate, said compound is pref. used in an amount of about 0.05-20pts.wt. of 1pt. of the diazonium salt and, when added to the microcapsule, pref. used in an amount of about 0.01-5pts.wt. of 1pt. of the diazonium salt.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a heat-sensitive recording material, and particularly to a fixable diazo thread heat-sensitive recording material.

(Prior art) Recording material 1゛1 used in a thermal recording method is commonly known as
The δ leuco color-forming heat-sensitive recording material is γ1. ing. However, this heat-sensitive recording material has the disadvantage that color develops in unexpected places due to harsh handling or heating after recording or adhesion of solvents, staining the recorded image. As a heat-sensitive recording material that solves these drawbacks, a diazo color-forming heat-sensitive recording material has been proposed in recent years (for example, in Japanese Patent Application Laid-Open No. 57-12
No. 3086, Journal of the Institute of Image Electronics Engineers, Earthworks, 290 (198
2))

This involves thermal recording on a recording material that uses a diazo compound, a coupling component, and a basic component (including substances that become basic when heated), and then irradiating light to decompose the unreacted diazo compound and develop color. It is something that makes it stop. surely,
According to this method, color development is stopped in areas that do not require recording (hereinafter referred to as
However, this recording material also has the drawback that pre-coupling progresses gradually during storage, resulting in undesirable coloring (fogging). Therefore, it has been attempted to prevent contact between the components and prevent pre-coupling by making one of the coloring components exist in the form of discontinuous particles (solid dispersion), but even in this case, However, there are disadvantages in that the storage stability (hereinafter referred to as raw storage stability) of the recording material is not yet sufficient and the thermal coloring property is reduced.

As another measure, it is known to separate the diazo compound and the camping component as separate layers in order to minimize contact between the components (for example, in the above-mentioned Japanese Patent Application Laid-Open No. 57-12
3086), although this method improves raw storage stability, the thermal color development is greatly reduced, and it cannot respond to high-speed recording with a short pulse width, making it impractical. In addition, as a method to satisfy both raw storage stability and thermal color development, either the coupling component or the basic substance is replaced with a non-polar waxy substance (Japanese Patent Application Laid-Open No. 142636/1983) or a hydrophobic polymer substance ( It is known to isolate it from other components by encapsulating it (Japanese Patent Application Laid-open No. 57-192944). However, these encapsulation methods involve melting a wax or polymer substance in its solvent, and melting or dispersing the coloring component in the solution to form a capsule. This is different from the concept of a normal capsule covered with a shell. Therefore, when the coloring component is dissolved and formed, the coloring component does not become the core material of the capsule and mixes uniformly with the encapsulating material, and precoupling gradually progresses at the wall interface of the capsule during storage. In addition, it has the drawback that the raw storage stability is not fully satisfied, and the coloring reaction does not occur unless the capsule wall is thermally melted, so the thermal coloring property is reduced. There was a manufacturing problem in that the solvent used to melt the liquid had to be removed.

As a heat-sensitive material that solves these problems, at least one of the components involved in the coloring reaction is used as a core material, and a wall is formed around this core material by polymerization to form microcapsules. 65043) A heat-sensitive recording material has been proposed.

(The problem that the invention is trying to solve) However,
Even with heat-sensitive recording materials produced by this microencapsulation method, the printed image after photofixing has insufficient fastness to light and heat, and the unprinted areas have a high yellowish tinge (
Due to this drawback, further improvements were required.

Therefore, a first object of the present invention is to provide a heat-sensitive recording material in which a thermochromic image after fixing has good fastness to light and heat.

A second object of the present invention is to provide a heat-sensitive recording material in which printed images can be fixed and the whiteness of non-printed areas is high.

A third object of the present invention is to provide a heat-sensitive recording material that is excellent in all of raw storage stability, image quality, and image storage stability.

A fourth object of the present invention is to provide a heat-sensitive recording material that is easy to manufacture.

(Means for Solving the Problems) The above aspects of the present invention provide a heat-sensitive recording material in which a heat-sensitive layer having a diazonium salt and a coupler is provided on a support, the heat-sensitive layer having the following general formula (1). This was achieved using a heat-sensitive recording material characterized by containing at least one of the compounds shown above.

General formula (1) In the formula, R represents a substituted or unsubstituted 4-piperidyl group, and particularly preferably, R1 represents a substituted or unsubstituted alkyl group (for example, a methyl group, a propyl group, a methoxyethyl group, hydroxyethyl group, etc.), substituted or unsubstituted alkenyl group (e.g. vinyl group, allyl group, etc.), substituted or unsubstituted alkynyl group (e.g. ethynyl group, propargyl group, etc.), substituted or unsubstituted alkynyl group (e.g. ethynyl group, propargyl group, etc.) Aralkyl groups (e.g. benzyl group, p-methoxybenzyl group, phenethyl group, etc.) or substituted or unsubstituted acyl groups (
For example, it represents an acetyl group, a chloroacetyl group, an acryloyl group, a methacryloyl group, a crotonoyl group, etc.).

R2 is a hydrogen atom or one or more substituted or unsubstituted alkyl groups which may be the same or different and which are substituted on the piperidine ring (for example, a methyl group, an ethyl group,
one or more substituted or unsubstituted alkyl groups which may be the same or different (e.g. methyl group, isopropyl group, t-butyl group, etc.);
t-amyl group, chloromethyl group, etc.).

Y represents a hydrogen atom or a substituted or unsubstituted alkyl group (eg, butyl group, dodecyl group, β-methoxycarbonylethyl group, φ + .

m is 1 or 2, and (n + p = 'l).

Among the compounds represented by the general formula (T), the following general formula (I
The effects of the present invention are more effectively exhibited when using the compound represented by a).

General Formula (Ia) In General Formula (Ia), R1, Y, m, and p represent the same meanings as in General Formula (I).

Typical examples of compounds represented by the general formula (1) used in the present invention are shown below, but the compounds are not limited to the same extent.

(Knee, 2) [Ding-3] [Ding-μ] I-1 [■-O] Cl-7] (I-1,1 (]--5') (E-10) General formula (1) The compound represented by is, for example, a West German patent (
Publication) No. 2,456,364, No. 2,647.452, No. 2,654,058, No. 2゜656.769,
and Japanese Patent Publication No. 57-20617, etc., and can be synthesized by the methods described therein.

These compounds can be used alone or in combination of two or more kinds when carrying out the present invention, and furthermore, other known anti-fading agents can also be used in combination.

Known anti-fading agents include hydroquinone+q, phenols, chromanols, coumarans, hindered amines, complexes, etc., such as JP-A-59-83162, JP-A No. 5 B-241dl No. 1, JP-A No. 52-15222.
No. 5, U.S. Patent No. 3,698°909, U.S. Patent No. 4,261
No. 1.593, British Patent No. 2.069,162 (A)
No. 2. 027. It is described in specifications such as No. 731.

These compounds may be added in the form of fine particles, but if the diazonium salt or coupler is microencapsulated, they can be added inside the microcapsule or both inside and outside the microcapsule. be. When added in the form of fine particles, approximately 0% per 1 part by weight of diazonium salt.
．． 05 to 20 parts by weight is preferred, particularly 0.2 to 5 parts by weight. When added into microcapsules, the amount is preferably about 0.01 to 5 parts by weight, particularly preferably 0.05 to 1 part by weight, per 1 part by weight of the diazonium salt. It may also be used in combination with other anti-fading agents.

The diazo compound used in the present invention has the general formula ArN2+
It is a diazonium salt represented by X- (in the formula, Ar represents an aromatic moiety, N2+ represents a diazonium group, and X- represents an acid anion), and develops color by causing a coupling reaction with a coupling component. , a compound that can be broken down by parents.

Specifically, the aromatic moiety is preferably one of 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,
Represents an alkoxy group, aryloxy group, arylamino group, or halogen (1°Br, C1, F).

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

Diazonium compounds that form salts include 4-diazo-
1-dimethylaminobenzene, 4-diazo-1-diethylaminobenzene, 4-diazo-1-dipropylaminobenzene, 4-diazo-1-methylbenzylaminobenzene, 4-diazo-1-dibenzylaminobenzene, 4- Diazo-1-ethylhydroxyethylaminobenzene, 4
-Diazo-1-diethylamino-3-methoxybenzene, 4-diazo-1-dimethylamino-2-methylbenzene, 4-diazo-1-benzoylamino-2゜5-jethoxybenzene, 4-diazo-1-morpholino -2,5
-Jethoxybenzene, 4-diazo-1-morpholino-
2,5-dibutoxybenzene, 4-diazo-1-anilinobenzene, 4-diazo-1-)ruylmercabutoe 2
．． 5-jethoxybenzene, 4-diazo-1,4-methoxyhenzoylamino-2,5-jethoxybenzene,
Examples include 4-diazo-1-pyrrolidino-2-ethylbenzene.

Specific examples of acid anions include cnF'7n+l coo- (n is an integer from 3 to 9), C
mF2m+I SO3″″ (m is an integer from 2 to 8), (C
j2F2ff+l5O2)2CH"-(ff is 1 to 18
), C(qH3)3 (n is an integer of 3 to 9), BF4'''', PF5-, and the like.

In particular, as the acid anion, one containing a perfluoroalkyl group or a perfluoroalkenyl group, or PF5- is preferable because it causes less increase in fog during raw storage.

As a specific example of a diazo compound (diazonium salt),
Examples include:

Human C4Hg Do< 0C2I Engineering 5 OczH5 0C4Hg C2H5 The coupling component used in the present invention is a diazo compound (
It couples with diazonium salt 5 to form a dye. Specific examples include resorcinol,
Phloroglycin, 2,3-dihydroxynaphthalene-6
-Sodium sulfonate, 1-hydroxy-naphthoic acid morpholinopropylamide, 1.5-dihydroxynaphthalene, 2.3-dihydroxynaphthalene, 2.3-dihydroxy-6-sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropyl Amide, 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-
Probylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, 12) L-nyl-3-methyl-5-pyrazolone, 1-(2°, 4°.

6°-trichlorophenyl)-3-benzamide-5
-pyrazolone, 1-(2′,4°,6°-trichlorophenyl)-3-anilino-5-pyrazolone, 1-phenyl-3-phenylacetamido-5-pyrazolone, and the like.

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. Examples of the basic substance include a poorly water-soluble or water-insoluble basic substance and a substance that generates alkali when heated. Basic substances that can be used include inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiacol, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, Examples include nitrogen-containing compounds such as imidacillins, triazoles, morpholines, piperidines, amidines, formazines, and pyridines. Specific examples of these include ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine,
Stearylamine, allyl urea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, 2-benzylimidazole, 4-phenylimidazole, 2-phenyl-4-methyl-imidazole, 2-undecyl-imidacillin, 2.4.5- 1-Lift-true 2-imidacilline, l.

2-diphenyl-4,4-dimethyl-2-imidacilline, 2-phenyl-2-imidapurine, 1°2.3-)riphenylguanidine, ■, 2-ditolylguanidine, l
, 2-dicyclohexylguanidine, 1,2.3-)dicyclohexylguanidine, guanidine trichloroacetate, N, N'-dibenzylpiperazine, 4.4゛
-dithiomorpholine, morpholinium trichloroacetate, 2-amino-benzothiazole, 2-benzoylhydrazino-benzothiazole, and the like. Two or more of these basic substances can also be used in combination.

The microcapsules used in the present invention are not only destroyed by heat and pressure as used in conventional recording materials, but also by heating, the core of the microcapsules and reactive substances existing outside the microcapsules are destroyed. Also included are microcapsules that become capable of reacting by penetrating the capsule wall.

From the viewpoint of thermochromic properties, the latter microcapsules are preferred. The case where this latter microcapsule is used will be explained in detail below.

Microcapsules are impermeable to substances at room temperature, but become permeable by heating, by dissolving or dispersing the reactive substance contained in the core substance of the microcapsules in a water-insoluble organic solvent, emulsifying the substance, and then transmitting the substance around the oil droplets. The microcapsule walls are formed by polymerization. In this case, the organic solvent preferably has a boiling point of 180° C. or higher. Specifically, phosphoric acid esters, phthalic acid esters, other carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, diarylethanes, and the like are used. Specific examples include tricresyl phosphate, trioctyl phosphate, octyldiphenyl phosphate, tricyclohexyl phosphate, dilauryl phthalate, dicyclohexyl phthalate, butyl oleate, diethylene glycol dibenzoate, dioctyl sebacate, dibutyl sebacate, dioctyl adipate, Trioctyl trimellitate, acetyltriethyl citrate, octyl maleate, dibutyl maleate, isopropylbiphenyl, isoamyl biphenyl, chlorinated paraffin, diisopropylnaphthalene, ■.

1°-Ditolylethane, 2,4-di-tert-aminophenol, N,N'-dibutyl-2-butoxy-
Examples include 5-1ert-octylaniline and the like. Among these, ester solvents such as dibutyl phthalate, tricresyl phosphate, diethyl phthalate, and dibutyl maleate are particularly preferred.

, a reactant forming a polymeric substance as the microcapsule wall is added inside the oil droplet and/or outside the oil droplet. Specific examples of polymeric substances include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin,
Examples include polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer, gelatin, polyvinylpyrrolidone, polyvinyl alcohol, and the like.

Two or more types of polymeric substances can also be used in combination.

Preferred polymeric materials are polyurethanes, polyureas, polyamides, polyesters, polycarbonates, particularly preferred are polyureas and polyurethanes.

Regarding the preparation of the microcapsule wall of the present invention, the effect is particularly great when using a microencapsulation method by polymerizing a glue actant from inside an oil droplet. That is, since a uniform particle size is formed within a short period of time, it is preferable for producing heat-sensitive recording materials with excellent shelf life.

This method and specific examples of compounds are described in U.S. Pat.
, No. 726.804, 3. 79f3. It is described in the specification of No. 669.

For example, when polyurethane is used as the capsule wall material, a polyvalent isocyanate and a second substance that reacts with it to form the capsule wall (such as a polyol) are mixed into the oily liquid to be encapsulated, emulsified and dispersed in water, and then By increasing the temperature, a polymer formation reaction occurs at the oil droplet interface, forming a microcapsule wall. At this time, a co-solvent with a low boiling point and strong dissolving power can be used in the oily liquid.

In this case, regarding the polyisocyanate-1 used and the polyol and polyamine that react with it, U.S. Pat.
No. 3,793,268, Special Publication No. 48-40347,
It is disclosed in JP-A-49-24159, JP-A-48-80191, and JP-A-48-84086, and these can also be used.

Furthermore, a tin salt or the like can also be used in combination to promote the urethanization reaction.

In particular, when a polyvalent isocyanate is used as the first wall-forming material and a polyol is used as the second wall-forming material, storage stability is good (preferably). Thermal permeability can also be changed arbitrarily.

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゜-biphenyludiisocyanate, 3,3
° -dimethyldiphenylmethane-4,4”-diisocyanate, xylylene-1,4-diisocyanate,
4.4-Diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1
, 2-diisocyanate, cyclohexylene-1,4-
Diisocyanates such as diisocyanates, 4,4°, 4
Triisocyanates such as ``-triphenylmethane triisocyanate, toluene-2,4,6-triisocyanate, 4,4''-dimethylphenylmethane-2,2
', 5.5'-Tetraisocyanates such as tetraisocyanate, adducts of hexamethylene diisocyanate and trimethylolpropane, 2.4-) adducts of lylene diisocyanate and trimethylolpropane, adducts of xylylene diisocyanate and trimethylolpropane. , isocyanate prepolymers such as adducts of tolylene diisocyanate and hexanetriol, and the like.

The polyol, which is the second wall-forming substance, includes aliphatic and aromatic polyhydric alcohols, hydroxy polyesters,
There are things like hydroxy polyalkylene ether.

Preferred polyols include polyhydroxy compounds having a molecular weight of 5,000 or less, in which the following groups (1,), (■), (III), or (IV) exist between two hydroxyl groups in the molecular structure.

(1) Aliphatic hydrocarbon group having 2 to 8 carbon atoms (If)-Furu10-Ar-0-Furuichi Here, Ar in (If), (III), and (rV) is substituted or unsubstituted. The aliphatic hydrocarbon group represents an aromatic moiety, and the aliphatic hydrocarbon group has -CnH2n- as a basic skeleton, and the hydrogen group may be substituted with another element.

To give specific examples, examples of (1) include ethylene glycol, l,3-propanediol, 1,4-butanediol, 1,5-bentanediol, l,6-
Hexanediol, l,? -hebutanediol, 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-bentanediol, 1,4-cyclohexane dimetatool, dihydroxycyclohexane, diethylene glycol, 1
．． 2.6-) Lihydroxyhexane, phenylethylene glycol, 1.1°1-trimethylolpropane, hexanetriol, pentaerythritol, glycerin and the like.

Examples of (If) include condensation products of aromatic polyhydric alcohols and alkylene quinides, such as 1,4-di(2-hydroxyethoxy)benzene and resorcinol dihydroxyethyl ether.

Examples of (1) include p-xylylene glycol, m-
Xylylene glycol, α, α° -dihydroxy-p
-diisopropylbenzene and the like.

Examples of (IV) include 4,4°-dihydroxy-diphenylmethane, 2-(p,p'-dihydroxydiphenylmethyl)benzyl alcohol, adduct 1 of ethylene oxide to bisphenol A, and adduct 1 of propylene oxide to bisphenol A. etc. The polyol is preferably used in a ratio of 0.02 to 2 moles of hydroxyl groups per mole of isocyanate groups.

When manufacturing microcapsules, water-soluble polymers can be used. The water-soluble polymer in this case may be any water-soluble anionic polymer, nonionic polymer, or amphoteric polymer. As the anionic polymer, both natural and synthetic polymers can be used. For example, -coo-1
Examples include those having -so3- groups and the like. Specific examples of anionic natural polymers include gum arabic and alginic acid, and examples of semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, sulfated cellulose, and lignin sulfonic acid.

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 nonionic polymers include polyvinyl alcohol, hydroxyethyl cellulose, and methyl cellulose.

Examples of amphoteric compounds include gelatin.

Among these, the preferred water-soluble polymer is polyvinyl alcohol, which has a degree of saponification of 75% or more and a degree of polymerization of 300%.
These water-soluble polymers are preferably used as a 0.01-20% by weight aqueous solution.

The particle size of the microcapsules is set to 20μ or less.Generally, if the particle size exceeds 20μ, the print quality tends to be poor.Especially when heating with a thermal head is performed from the coating layer side, the particle size should be 8μ or less to avoid pressure capillary. is preferred.

The diazo compound, the coupling component, and the basic substance used as necessary, which are the main components of the heat-sensitive layer of the heat-sensitive recording material of the present invention, may be used as the core material of the microcapsules, either alone or in combination. , three types can also be used as core materials for microcapsules. When two types are contained in the core material of microcapsules, they may be in the same microcapsule or in separate microcapsules. Further, when three types are contained in the core material of a microcapsule, it is not possible to simultaneously contain the three types in the same microcapsule, but there are various combinations.

Other ingredients not contained in the core material of microcapsules are:
Used in the outer heat-sensitive layer of microcapsules.

The above-mentioned color image stabilizer used in the present invention may be present in the core of the microcapsule or outside.

When manufacturing microcapsules, they can be made from an emulsion containing 0.2 mm% or more of the component to be microencapsulated.

Diazo compound used in the present invention, coupling component,
And whether the basic substance used as necessary is contained inside the microcapsule or in the heat-sensitive layer outside the microcapsule, the coupling component is 0.1 to 1 part by weight of the diazo compound. It is preferable to use 10 parts by weight of the basic substance and 0.1 to 20 parts by weight of the basic substance. Also, the diazo compound is 0.05 to 5.0 g/+
It is preferable to apply d.

When the diazo compound, camping component, and basic substance used in the present invention are not microencapsulated, they are preferably used after being dispersed in solid form with a water-soluble polymer using a sand mill or the like. Preferred water-soluble polymers include water-soluble polymers used when making microcapsules.

In this case, the concentration of the water-soluble polymer is 2 to 30% by weight, and the diazo compound, coupling component, and basic substance are each added in an amount of 5 to 40% by weight with respect to the water-soluble polymer solution. be done. Dispersed particle size is 10μ
The following are preferred.

The G3 thermal recording material of the present invention contains hydroxy compounds, carbamate ester compounds,
Aromatic methoxy compounds or organic sulfonamide compounds can be added. These compounds can lower the melting point of the coupling component or basic substance or improve the thermal permeability of the microcapsule wall, resulting in a higher practical concentration during thermal recording. it is conceivable that.

Specific examples of hydroxy compounds include pt-butylphenol, pt-octylphenol, p-α-cumylphenol, pt-pentylphenol, m-xylenol, 2.5-dimethylphenol, 2. 4.5
-) dimethylphenol, 3-methyl-4-isopropylphenol, p-benzylphenol, 0-cyclo-
hexylphenol, p-(diphenylmethyl)phenol, p-(α,α-diphenylmethyl)phenol,
0-phenylphenol, ethyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p
-methoxyphenol, p-butoxyphenol, p-
Hebutyloxyphenol, p-benzyloxyphenol, dimethylvanillin 3-hydroxyphthalate, ■,
1-bis(4-hydroxyphenyl)dodecane, 1.1
-bis(4-hydroxyphenyl)-2-ethyl-hexane, 1.1-bis(4-hydroxyphenyl)-2-
Methyl-pentane, 2.2-bis(4-hydroxyphenyl)-hepcumvanillin, 2-t-butyl-4-methoxyphenol, 2゜6-simethoxyphenol, 2,
Phenol compounds such as 2°-dihydroxy-4-methoxybenzophenone, 2,5-dimethyl-2,5-hexanediol, resorcinol di (2-hydroxyethyl) ether, resorcinol mono (2-hydroxyethyl) ether, salicyl alcohol, 1.4-di(
hydroxyethoxy)benzene, p-xylylene diol, 1-phenyl-1,2-ethanediol, diphenylmethanol, 1.1-diphenylethanol, 2-methyl-2-phenyl-1,3-propanediol, 2.
6-dihydroxymethyl-p-cresol benzyl ether, 2.6-dihydroxymethyl-p-cresol benzyl ether, 3-(o-methoxyphenoxy)-1
, 2-propanediol, and the like. Specific examples of the carbamate ester compounds include N-phenylcarbamate ethyl ester, N-phenylcarbamate benzyl ester, N-phenylcarbamate phenethyl ester, carbamate benzyl ester, carbamate butyl ester, carbamate isopropyl ester, etc. Specific examples of aromatic methoxy compounds include 2-methoxybenzoic acid, 3.
Examples include 5-dimethoxyphenyloctaic acid, 2-methoxynaphthalene, 1,3.5-trit-xybenzene, p-dimethoxybenzene, p-benzyloxymethoxybenzene, and the like.

Specific examples of organic sulfonamides include p-toluenesulfonamide, 0-toluenesulfonamide, p-ethylbenzenesulfonamide, 0-ethylbenzenesulfonamide, m-ethylbenzenesulfonamide, benzenesulfonamide p-)toluenesulfonamide, N −(
p-methoxyphenyl)-p-toluenesulfamide,
N-(0-methoxyphenyl)-p-toluenesulfonamide, N-(p-chlorophenyl)-p-toluenesulfonamide, N-(o-chlorophenyl)-p-)luenesulfonamide, N-(p-tolyl) )-p-) luenesulfonamide, N-(0-hydroxyphenyl)-p
-) Luenesulfonamide, N-benzyl-p-toluenno, sulfonamide, N-(2-phenethyl) -p-
1-Luenesulfonamide, N-(2-hydroxyethyl)-p-)Luenesulfonamide, N-(3-, J toxypropyl)-p-)Luenesulfonamide, Methanesulfonamide, N-(p-1 -zyl)sulfonamide, N-(o-)zyl)sulfonamide, N-(p-methoxyphenyl)sulfonamide, N-(0-methoxy)sulfonamide, N=(p-chlorophenyl)sulfonamide, N-(o-chlorophenyl)sulfonamide, N-(2,4-xylyl)sulfonamide, N-(
p-ethoxyphenyl)sulfonamide, N-benzylmedanesulfonamide, N-(2-phenoxyethyl)
Examples include, but are not limited to, methanesulfonamide, 1,3-bis(methanesulfonylamino)benzene, 1,3-bis(p-toluenesulfonylamino)propane, and the like.

These compounds can be used by forming microcapsules together with the core material of the cocapsule, or by being added to the coating solution of the heat-sensitive recording material and existing outside the microcapsules; In either case, the amount used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, per 1 part by weight of the coupling component, but in order to adjust the color density to the desired level. can be selected as appropriate.

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 yellowing of the background after photofixing.

What is vinyl monomer? Its chemical structure [No. 1 is at least 1
A compound having ethylenically unsaturated bonds (vinyl group, vinylidene group, etc.), including monomers, prepolymers,
That is, it has chemical forms such as dimers, 39-mers, other oligomers, mixtures thereof, and copolymers thereof. Examples thereof include unsaturated carboxylic acids and salts thereof, esters of unsaturated carboxylic acids and aliphatic polyhydric alcohol compounds, amides of unsaturated carboxylic acids and aliphatic polyhydric amine compounds, and the like.

The vinyl monomer is 0.2 parts by weight of the diazo compound.
It is used in a proportion of ~20 parts by weight, preferably 1-10 parts by weight.

The vinyl monomer is used by being contained in the core material of the microcapsule together with the diazo compound, but at this time, the solvent for the core material (
Alternatively, part or all of the organic solvent used as a dispersion medium can be replaced with a vinyl monomer. In this case, it is not necessary to add enough to harden the core material.

When the heat-sensitive recording material of the present invention contains a diazo compound as a core material, the diazo compound present in the aqueous phase and the diazo compound in incomplete capsules can be removed by containing a camping reaction deactivator outside the microcapsules. (i.e., the diazo compound that is not completely blocked by the capsule wall) and the coupling reaction quencher react with each other, causing the diazo compound to lose its camping reaction (coloring reaction) ability, thereby preventing fogging. .

The coupling reaction deactivator may be any substance that reduces the coloring of a solution in which the diazo compound is dissolved, and may be used as a coupling reaction deactivator. The diazo compound can be selected by adding the compound and observing the color change of the diazo compound.

Specifically, hydroquinone, sodium bisulfite, potassium nitrite, hypophosphorous acid, and chloride No. 1! Examples include I, formalin, etc. In addition to this, H.

The Aromatic D by Sawn ders
iazo-CompoundsandTheirT
electrical applicationsJM,
C,,M.

A, (Cant ab,) B, Sc, (Lon
Don) published in 1949, pages 105-306.

The campling reaction quencher is preferably a quencher with little coloring itself and a quencher with few side effects, and particularly preferably a water-soluble substance.

The coupling reaction deactivator is used to the extent that it does not inhibit the thermal coloring reaction of the diazo compound.
It is preferable to use the deactivator in a range of 0.01 mol to 2 mol, particularly in a range of 0.02 mol to 1 mol, based on the mole.

The coupling reaction deactivator used in the present invention is a liquid in which microcapsules containing a diazo compound are dispersed after being dissolved in a solvent, a liquid in which a coupling agent or a basic substance is dispersed,
Alternatively, it can be used by adding it to a mixed solution of these, but it is particularly preferable to use the deactivator in the form of an aqueous solution.

The heat-sensitive recording material of the present invention contains pigments such as silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide, calcyano carbonate, etc., for the purpose of preventing sticking to heat and throat and improving writing properties. Fine powders such as styrene beads and urea-melamine resin (5) can be used. Similarly, metal soap powder 1 can also be used to prevent sticking. The appropriate amount of these to be used is 0.2 to 7 t'/d.

A heat-melting substance can be used in the heat-sensitive recording material of the present invention in order to increase the heat-recording density. Such a heat-melting substance is a substance that is solid at room temperature, has a melting point of 50 to 150°C and melts when heated by a thermal head, and is a substance that dissolves a diazo compound, a coupling component, or a basic substance. The thermofusible substance is dispersed in the form of particles of 0.1-10μ and used in an amount of solids content of 0.2-7 g/m. Specific examples of heat-melting substances include fatty acid amides, 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 using a suitable binder.

As a binder, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, bitroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, sudylene-butadiene latex, acryloni! - Various emulsions such as di-butadiene latex, polyvinyl acetate, polyacrylic ester, and ethylene-vinyl acetate copolymer can be used. The amount used is 0.5-5 g/m solids.

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

The heat-sensitive recording material of the present invention can be produced by preparing a coating solution containing a diazo compound, a coupling component, a basic substance, other additives, etc., and coating it on a support such as paper or a synthetic resin film by bar coating, blade coating, etc. Air knife coating, gravure coating,
Apply by coating methods such as roll coating, spray coating, dip coating, etc. and dry to a solid content of 2.5 to 25 g.
/ l of a heat-sensitive layer. Alternatively, the main component of the coupling component, a basic substance, and other additives may be added as core materials of microcapsules, or they may be mixed after solid dispersion or dissolved as an aqueous solution and then applied. Make a liquid, apply it on a support, dry it, and get a solid content of 2 to 10 tons? A precoat layer of /d is provided, and the main component diazo compound and other additives are added thereon as the core material of the microcapsules.
Alternatively, after solid dispersion or after γδ decomposition as an aqueous solution, a coating solution made by mixing the mixture is applied and dried to give 1 to 15 g/
It is also possible to use a laminated type in which a coating layer d is provided. A laminated type heat-sensitive recording material may be one in which the order of the layers I- and the above-mentioned Mi layer is reversed, and the coating method may be sequential coating or simultaneous coating of the laminated layers.

It is also possible to provide an intermediate layer on the support as described in Japanese Patent Application No. 59-177669, et al., and then coat the heat-sensitive layer.

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

(Effects of the Invention) The heat-sensitive recording material of the present invention has good image storage stability after recording and has a low coloring density in the background area after photofixing, so it is particularly effective for long-term storage of recorded images. Furthermore, the shelf life of the photosensitive material and the shelf life of recorded images can be further improved by microencapsulating at least one of the compounds involved in color development.

(Example) Examples are shown below, but the present invention is not limited thereto. Note that "parts" indicating the amount added represent "parts by weight."

Example 1 To 100 g of compound A, 5% polyvinyl alcohol (P
VA205: 200 g of an aqueous solution (trade name manufactured by Kuraray ■) was added and dispersed in a ball mill for 24 hours to obtain Solution A. 18g of compound B-1, 2g of compound B-2, 2g of compound C
200 g of a 5% polyvinyl alcohol aqueous solution was added to 60 g of 0 g of the compound, and the mixture was dispersed in a ball mill for 24 hours to obtain liquid BD.

Next, 600 g of water was added to 400 g of light calcium carbonate and dispersed using a disilver to obtain a pigment liquid.

Furthermore, compounds exemplified as color image stabilizers in this specification (
1-1) 30g of 5% polyvinyl alcohol aqueous solution 17
0 g and dispersed in a ball mill for 24 hours to obtain Solution E.

Measure out 2 parts of liquid A, 10 parts of liquid B-D, 5 parts of pigment liquid, and 3 parts of liquid E, split the coating liquid, and after drying on high-quality paper, the coating amount is 8 parts.
It was barcoded to be g/rd. Drying was performed at room temperature to obtain a heat-sensitive recording material (1).

(Test method) The obtained heat-sensitive recording material was thermally recorded using a Gull mode thermal printer (UF-1 manufactured by Matsushita Electric Transmission Co., Ltd.), and then the entire surface was exposed using Ricopy Super Dry 100 (manufactured by Ricoh B). It took hold. The density of the obtained recorded image was measured using a Macbeth reflection density needle. In addition, the yellow density of the background portion was also measured in the same manner. The results are shown in Table 1. On the other hand, when thermal recording was attempted again on the fixed portion, it was confirmed that no image was recorded and the image was fixed.

Next, in order to examine raw storage stability, we examined the background density (fog) of the heat-sensitive recording material and the heat-sensitive recording material at 40°C and 90% relative humidity.
After storing in a dark place under RH conditions for 24 hours and performing a forced deterioration test, fog was measured using a Macbeth reflection densitometer to measure changes in fog density. After fixing, the recorded image obtained by semi-fixing was measured using a xenon fade meter (Suga Test & i, FAL) to check the stability of the dye image and the yellowing of the background.
-25AX-HC type) for 24 hours, the density of the recorded image area and the background area was measured. The results are shown in Table 1.

The compounds used for sample preparation are as follows.

Compound A diazonium salt C4Hg Compound B-1 = Coupler Compound B-2: Coupler O = 0 Compound C: Organic basic compound ＼Di compound 2 color development improver CH2CH2- ・-3O2NH2 Example 2゜A thermosensitive recording material (2) was obtained in exactly the same manner as in Example 1 except that compound (1-3) was used instead of compound (I-1) as liquid E in Example 1. A test was conducted. The results are shown in Table 1.

In addition, compound (1-3) is the number of the compound exemplified in this specification. Comparative Example 1 A comparative sample (ratio -1) was obtained in the same manner as in Example 1 except that liquid B was not used in Sakai.

The test was conducted in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 Next, as an example, an example in which Compound A was microencapsulated is shown.

50 g of compound A, 150 g of methylene chloride, 50 g of tricresyl phosphate, 150 g of trimethylolpropane trimethacrylate, 7 of the trimethylolpropane 3:1 adduct of m-hemisilylene diisocyanate.
200 g of a 5% ethyl acetate solution (Cuquenate DIION: trade name manufactured by Takeda Pharmaceutical Co., Ltd.) was uniformly mixed to obtain an oil phase liquid.

On the other hand, 7% polyvinyl alcohol (PVA217E:
A saponification degree of 88 to 89% and a polymerization degree of 1700 (trade name manufactured by Kuraray Co., Ltd.) was used to prepare 600 g of a water-soluble polymer aqueous solution.

Attach DiSilver to a 51 stainless steel pot equipped with a hot bath, add a protective colloid aqueous solution, then add the oil phase solution while stirring DiSilver until the average particle size becomes approximately 1.5μ when observed under a microscope. Emulsification and dispersion was performed. After the dispersion was completed, the stirring was loosened, and 42°C hot water was passed through the hot bath to carry out the encapsulation reaction at an internal temperature of 40°C for 3 hours. Obtained A
The solution was used after removing the diazonium salt that could not be encapsulated with the ion exchange resin.

A°Liquid Part B-D liquid, pigment liquid and E used in Example 1
A coating solution was prepared using 7 parts, 3.5 parts, and 2.1 part of the solution, respectively, and coated on high-quality paper so that the coated amount after drying was 10 g/m to prepare a heat-sensitive recording material. (5) was produced.

The results of the test conducted in the same manner as in Example 1 are shown in Table 1.

Example 4 A heat-sensitive recording material (4
) was obtained.

The results of the test conducted in the same manner as in Example 1 are shown in Table 1.

Example 5 Next, as an example, an example in which Compound A and a color image stabilizer were microencapsulated is shown.

Microencapsulation was carried out in the same manner as in Example 3 except that 5 g of compound (1-1) was added to the oil phase solution of Example 3 to obtain liquid A'', and a heat-sensitive recording material ( 5)
I got it.

The results of the test conducted in the same manner as in Example 1 are shown in Table 1.

Example 6 Compound (1) was used instead of compound N-1 used in Example 5.
A thermosensitive recording material (6) was obtained in exactly the same manner as in Example 5, except that -3) was used. The results of the test conducted in the same manner as in Example 1 are shown in Table 1.

Comparative Example 2 A comparative sample (ratio-2) was obtained in exactly the same manner as in Example 3, except that liquid E was not used.

Table 1 shows the results of the test conducted in the same manner as in Example 1.

As is clear from the results in Table 1, the heat-sensitive recording material of the present invention has improved background density during recording, image deterioration after recording, yellowing of the background after recording, and shelf life before recording. It has been proven that there is.

This effect was the same even when the diazo compound was microencapsulated, and these Examples demonstrated the effectiveness of the present invention.

Claims (1)

[Scope of Claims] 1) A heat-sensitive recording material in which a heat-sensitive layer having a diazonium salt and a coupler is provided on a support, wherein the heat-sensitive layer is selected from compounds represented by the following general formula [I]. A heat-sensitive recording material characterized by containing at least one kind. General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. represents one or more optionally substituted or unsubstituted alkyl groups.Y represents a hydrogen atom or a substituted or unsubstituted alkyl group.m is 1 or 2, and m+p=2) 2) Heat sensitivity Among the diazonium salts and couplers in the layer,
The heat-sensitive recording material according to claim 1, wherein at least one of the components is encapsulated in microcapsules. 3) The heat-sensitive recording material according to claim 2, wherein the diazonium salt is encapsulated in microcapsules.