JPS61254388A - Thermal recording material - Google Patents

Abstract

PURPOSE:To provide a thermal recording material having excellent preservability and high color forming property, by microencapsulating at least one of a diazo compound and a coupling component together with a specified organic solvent. CONSTITUTION:To form microcapsules, a diazo compound or a coupling component to be microencapsulated is dissolved in a specified organic solvent, the solution is emulsified in water, and microcapsule walls are formed around liquid droplets by polymerization. The organic solvent is a compound of the formula, and is particularly preferably diphenylcresyl phosphate. In microencapsulation, 2-50pts.wt. of the solvent and 1-50pts.wt of the diazo compound or the coupling component are used per 24pts.wt. of the microcapsule wall material. The diazo compound is a diazonium salt of general formula: ArN2<+>X<->, wherein Ar is aromatic moiety, N2<+> is diazonium group, and X<-> is acid anion.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a heat-sensitive recording material.
The present invention relates to a heat-sensitive recording material that has excellent storage stability before heat recording, has high color density during heat recording, and has little background fog.

"Prior Art" The heat-sensitive recording method (1) does not require a real hawk. (2) When the support is paper, the paper quality is similar to ordinary paper; (3) it is easy to handle; (4) the color density is high; (5) the recording device is simple and inexpensive; (6) Because it has advantages such as no noise during recording, it has become rapidly popular in the field of facsimiles and printers in recent years.

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 develops color in unexpected places due to harsh handling, heating, or adhesion of solvents after recording.
It has the disadvantage of contaminating the surface. In recent years, research has been actively conducted on diazo color-forming heat-sensitive recording materials as heat-sensitive recording materials that do not have these drawbacks. For example, Tokukai Akira! 7-7λ
sot No. 2, Gataka Electronics Society Journal, //%2rio (iyrx
), etc., thermal recording is performed on a recording material using a diazo compound, a coupling component, and a chlorinated component (including substances that become basic when exposed to heat), and then light irradiation is performed. It decomposes unreacted diazo compounds and stops color development.

It is true that with this method, it is possible to stop color development (hereinafter referred to as fixing) in areas where recording is unnecessary.However, pre-coupling gradually progresses during storage of this recording material, resulting in undesirable coloring (fogging). may occur.

Various new functions have also been required in the field of recording, and for example, facsimile machines and color printers that transmit color originals have been developed. Inkjet methods and thermal transfer methods are used as these printing methods. However, these have drawbacks such as clogging of ink nozzles and generation of large amounts of unnecessary ink sheets. Thermal paper that can produce multiple colors using a thermal method is known. For example, there are those that apply diazosulfonate and those that combine diazosulfonate and leuco coloring system. Since these are compounds that cause a color reaction and need to have a difference in thermal response, the color forming materials that can be used are extremely limited, which greatly limits the design and production of recording materials.

In general, text recording is mainly carried out in thermal recording, but in recent years there has been an increasing demand for image quality recording with gradation, such as that of the TV ITiI.

There are two ways to express gradation: one is to keep the recording density constant and change the recording area, and the other is to keep the recording area constant and change the recording density. Since there is a limit to the expression of , the latter is better.

However, with conventional thermal paper, the former method is appropriate;
The latter method is not very suitable. This is because the latter method requires intermediate density printing on thermal paper. That is, it is required that the applied energy changes with a certain degree of gentleness (the rate of change is not too large).

However, conventional leuco color-forming thermal recording paper is made by finely dispersing leuco dye and phenolic color developer into micron-order sizes, mixing them, and applying the mixture to a paper support, which is then heated with a thermal head. Then, there is a monomer that develops color by melting and mixing the coloring components with each other, but it is not easy to create differences in temperature characteristics between particles or between coating layer parts.

Therefore, in order to solve these problems, we have developed a method in which at least 1 m of the components involved in the color reaction are declared in the core material, and a wall is formed around this core material by polymerization to form microcapsules (%H Showa zr-tzo≠No. 3)
We have discovered an excellent heat-sensitive recording material by combining a plurality of microcapsules with different heat-responsiveness and having different wall materials. They also discovered that a multicolor heat-sensitive recording material can be realized, and each
% hope! 71r/I presented it to Hirohiro Tarata.

``Problems to be Solved by the Invention'' However, even in heat-sensitive recording materials produced by this microencapsulation method, unexpected fogging often occurs during storage.

Furthermore, it is desired to further improve thermochromic properties.

``Object of the Invention'' Therefore, the first object of the present invention is to provide a heat-sensitive recording material that has excellent shelf life and high thermochromic properties.

A second object of the present invention is to provide a heat-sensitive recording material with excellent manufacturing suitability.

"Means for Solving the Problems" As a result of intensive research, the present inventors have found that in a heat-sensitive recording material having a heat-sensitive layer consisting of a diazo compound and a coupling component, at least 1 m of the diazo compound and the coupling component The problem was solved by a heat-sensitive recording material characterized in that it is encapsulated in microcapsules together with an organic solvent, and the organic solvent is a compound represented by the following general formula.

general formula In the formula, R represents a substituted or unsubstituted aryl group.

More specifically, the aryl group is preferably a phenyl group, the naphthyl group or fc is preferably an anthryl group, and the substituent is preferably an alkyl group having carbon number/~μ.

"Operation" The microcapsules of the present invention can be destroyed by heat or pressure, as used in conventional recording materials, to separate the reactive substances contained in the core of the microcapsules and the reactive substances outside the microcapsules. Rather than causing a coloring reaction upon contact, the reactive substance present in the core and outside of the microcapsule is heated to primarily penetrate through the microcapsule wall and cause a reaction.

The microcapsules of the present invention contain a diazo compound or a coupling component as a core substance.

After being dissolved in the organic solvent of the present invention and emulsified in water, microcapsule walls are formed in droplets by polymerization.

The organic solvent of the present invention is a compound represented by the above general formula, and diphenyl cresyl phosphate is particularly preferred.

The organic solvent of the present invention has higher solubility than conventional phosphate ester compounds, and causes less background fog when used in heat-sensitive recording materials. Although the effect on the occurrence of skin fog is not clear, it is expected that the organic solvent affects the formation of microcapsule walls. In particular, it is estimated that it affects the density of the microcapsule wall, which in turn affects the occurrence of skin fogging.

What is the amount of spout used for the microcapsules of the present invention?

The organic solvent of the present invention is 2.j0 parts by weight, and the diazo compound or coupling component is /-j0 parts by weight, based on 2 parts by weight of the microcapsule wall material. Even more preferably, organic solvent -2 to 30! 2 to 75 parts by weight of the diazo compound or coupling component.

The diazo compound used in the present invention has the general formula A r N
2 +)r (in the formula, Ar represents an aromatic moiety, and N
+ represents a diazonium group, and X- represents an acid anion. ) It is a diazonium salt that can develop a color by causing a unidirectional pulling reaction with a single force pulling component, and is also a compound that can be decomposed by light.

Specifically, as the aromatic moiety, those having the following general formula are preferable.

In the formula, Y is a hydrogen atom-substituted amino group, an alkoxy group, an aryloxy group, an arylthio group, an alkylthio group, or
Represents an acylamino group; % R is a hydrogen atom, an alkyl group,
Represents an alkoxy group, aryloxy group, arylamino group, or halogen (1°Br, CI, F).

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

Specific examples of diazoniums that form salts include diazo-1-dimethylaminobenzene%≠-diazo-1-diethylaminebenzene, diazo-7-dipropylaminobenzene, ≠-diazo/-methylbenzylaminobenzene, and 4t-diazo-1-dimethylaminobenzene. ”/-/-dibenzylaminobenzene, μm diazo-/-1f-hydroxyethylaminobenzene.

μm diazo-1-diethylamine-3-methoxybenzene, ≠-diazo-7-dimethylamino-comethylbenzene, μm diazo-1-diethylamine-3-methoxybenzene, μm diazo-1-diethylamine-3-methoxybenzene, μm diazo-1-diethylamine-2! -Jethoxybenzene, μm shea, /”-/-Morpholinobenzene% Gusiaso/-Morpholino-2,!-Jethoxybenzene, Hiro-Diazo-!-Morpholinoco, j-
Dibutoxybenzene, ≠-diazo/-anilinobenzene, ≠-diazo/-)ruylmercabutoe2. J-jethoxybenzene, Hiro-diazo-1,≠-methoxybenzoylaminoλ,! -jethoxybenzene, Hiro-diazo-1-pyrrolidino-2-ethylbenzene, and the like.

A specific example of an acid anion is (2h p 2b + ”
C00- (n is an integer from 3 to 2), Cm F Z rn
10' S O3 (m is -z ~ r-tv integer), (C,
F2. +□802) 20H (1 is an integer of /-/r).

c(CH3)3 r Examples include BF4, PF, -, and the like.

As the dianic acid anion, those rich in perfluoroalkyl groups or non-fluoroalkenyl groups or PF, - are preferable because they cause less increase in fog during raw storage.

Specific examples of diazo compounds (diazonium salts) include the following examples.

C4H9 0C4H0 QC4H0 C2H3 C(CH3)3 QC4H.

QC2H.

QC, Ho C4H9 The coupling component used in the present invention is one that forms a dye by coupling with a diazo compound (diazonium salt) in a basic atmosphere.

There are coupling components whose color development is promoted by a basic substance, and coupling components whose color development is high in color density even in the absence of a basic substance. Specific examples of coupling components whose color density is promoted by basic substances include resorcinol, phloroglucin, and co.

3-dihydroxynaphthalene-3-sulfonic acid) I
J+1/mu, l-hydroxynonaphthoic acid morpholinopropylamide, /, J'-dihydroxynaphthalene, λ, 3-dihydroxynaphthalene, 2゜3-dihydroxy-t-sulfanylnaphthalene, non-hydroxy-3-naphthoic acid anilide , 2-hydroxy-3-naphthoic acid 2/-methylanilide, no-hydroxy-3-
Naphthoic acid ethanolamide% λ-hydroxy-3-naphthoic acid octylamide% No-hydroxy-3-naphthoic acid-N-dodecyl-oxy-probylamide, No-hydroxy-3-naphthoic acid tetradecylamide, Acetanilide, Acetoacetanilide, Inzoylacetani IJ)', 1-7enyl J-Mef-Yo-pyrazolone, 7(2/,≠1.41)dicyclophenyl)-3-benzamide-! −Hirazolone, /−(λ′,
≠/,,G/hdicyclophenyl)-3-72! j
/ -! -Hiraso o7, /-phenyl-3
-phenylacetamido-j-pyrazolone and the like.

Coupling components that produce high color density even in the absence of a basic component include active methylene compounds, aromatic amine compounds, and aromatic hydroxy compounds that have a basic group in their molecules. is β−
Ketocarboxylic acid amides [for example, (/zoylacetani; knot, pyhaloylacetanilide, l,3-bis(benzoylacetamino)toluene%/, J-bis(pivaloylacetaminomethyl)benzene, etc.)] ,
Pyrazolones [e.g. 3-methyl-7-phenylpyrazolone, 3-hexylcarbamoyl-l-phenylpyrazolone, J-myristoylamino-/-(λ,≠,4-trichlorophenyl)pyrazolone, etc.], barbylic acids [e.g. , 3-didodecylbarbic acid, /, 3
-dicyclohexylbarbic acid% l-octyl-
3-stearylbarbic acid (!:)-'! '-Cyclohexundiones [e.g. j, j-dimethyl-/,
J-cyclohexanedione, 2,2-dimethyl-≠-phenyl/, J-cyclohexanedione], and the like.

As aromatic amine compounds, α-naphthylamine,
β-naphthylamine, l-anilino-naphthalene, 2-
Anilino-naphthalene, 3-amino-diphenylamine, ≠, 3'-diaminodiphenylmethane%N, N-dicyclohexylaniline, λ-aminocarbazole, J-
Examples include organic acid salts and inorganic acid salts of aromatic amines such as phenylindole, l-phenyl-comethylindole, p-toluenesulfonate of N,N-dimethylaniline, α-naphthylane hydrochloride, and the like.

Examples of aromatic hydroxy compounds having a basic group in the molecule include 2-hydroxy-3-naphthoic acid-3'-morpholinopropylamide, λ-hydroxy-3-naphthoic acid-λ'-diethylaminoethylamide% cohydroxy-3- naphthoic acid-3-piperidinopropylamide,
Euhydroxy-3-naphthoic acid-37-piperidinopropylamide % Co-hydroxy-3-naphthoic acid-p
-(3/N/-cyanoguanidinopropylnooxyanilide, salicylic acid-p-(j'-morpholinopropyl)
Oxyanilide, l-naphtho-ruder-sulfone rR3
Aromatic hydroxy compounds having residues such as /-diethylaminepropylamide, l-hydroxyquinoline-≠-sulfonic acid-λ'-diethylaminoethylamide, and organic carboxylic acid salts of amines that generate basicity by heating [e.g. -Hydroxy-3-naphthoic acid-3'-
Trichloroacetate of morpholinopropylamide.

/-f phenylthioacetate of phtorudasulfonic acid-3'-diethylaminopropylamide, etc.). Furthermore, by using two or more of these coupling components in combination, it is possible to obtain a painter of any desired color tone.

In the present invention (1cH), a basic substance can be added for the purpose of promoting thermal color development, and as the basic substance, a poorly water-soluble or water-insoluble basic substance or a substance that generates dialkali when heated is used.

Basic substances include inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidacillins, triazoles. Examples include nitrogen-rich compounds such as lysines, amidines, formazines, and pyridines. Specific examples of these are:
Example ammonium acetate, tricyclohexylamine,
Tribenzylamine, octadecylbenzylamine, stearylamine, allyl urea, thiourea, methylthiourea, allylthiourea, ethylenethiourea%2-benzylimidazole, 4t-phenylimidazole, +2-7
Enyl-goomethyl-imidazole, λ-undecyl-imidacillin, recognition, noon,! - tri7lyleucoimidazoline, l.

Cordiphenyl-coimidazoline, 4A-dimethyl-coimidazoline, λ-phenyl-coimidazoline% l.

2, J-) IJ phenylguanidine, l,2-ditolylguanidine.

l, λ-dicyclohexylguanidine, 1,2. ! −)
Licyclohexyguanidine, guanidine trichloride, N'-dibenzylpiperazine, ≠, 4C'-dithiomorpholine.

Morpholinium trichloroacetate% co-aminobenzothiazole% copenzoylhydrazinobenzothiazole. Two or more of these basic substances can also be used in combination.

The microcapsules of the present invention are made by emulsifying a diazo compound or a coupling component and the organic solvent of the present invention as a core material, and then forming a wall of a polymeric material around the oil droplets; forming a polymeric material. The actant is added to the interior of the oil droplet and/or to the exterior of the oil droplet. A specific example of a polymer substance is:

Polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer, gelatin,
Examples include polyvinylpyrrolidone and polyvinyl alcohol.

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

Preferred polymeric substances are polyurethane and polyurea.

Polyamide, polyester, polycarbonate,
More preferred are polyurethane and polyurea.

Although the organic solvent of the present invention is used for emulsification, conventionally known phthalate esters,
Boiling point of fatty acid amide, alkylnaphthalene, etc. l♂0°C
The above organic solvents and auxiliary solvents such as methylene chloride can also be used in combination.

The microcapsule wall of the present invention is particularly effective when using a microencapsulation method in which adhesive actant is polymerized from inside the oil droplet. That is, it is possible to obtain capsules, which are desirable as a recording material and have a uniform particle size and excellent storage stability, within a short period of time.

For details on this method and specific examples of compounds, please refer to US@Patent J
, 72A, No. 1r04A, No. 3, 7, No. 6.6ty.

For example, when polyurethane is used as a capsule wall material, a polyvalent incyanate and a second substance (for example, a polyol) that reacts with it to form the capsule wall are mixed into an oily liquid to be encapsulated, emulsified and dispersed in water, and then heated to than to rise.

A polymer formation reaction occurs at the oil droplet interface to form the microcapsule wall. At this time, if a co-solvent with a low boiling point and strong dissolving power can be used in the oily liquid, the polyincyanate used and the polyol or polyamine that reacts with it are described in US Patent No. 32f/Jl#1.
No. 3773t9j, No. 37ri 324r, Tokuko Sho≠! -≠03≠7 issue, same≠2-2≠/jri issue, JP-A-4
4f-401? and AT-RPOR No. 6, and they can also be used.

In addition to the method described above, the capsule wall is preferably a polymeric material formed by the reaction of a polyvalent incyanate and a polyol. The coloring temperature can be changed by the combination of polyvalent incyanate and polyol.

Examples of the polyvalent incyanate include m-phenylene diisocyanate, p-phenylene diisocyanate,
6-drylene diincyanate, 2. Hirotolylene diisocyanate, naphthalene-1, μm diincyanate, diphenylmethane-French, g'-diisocyanate b 3r''-dimethoxida, μ'-biphenyl diisocyanate, '137-dimethyldiphenylmethane≠, 4A'-diisocyanate , xylylene-7゜μm
Diincyanate, ≠, μ'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, prohylene-1, λ-diincyanate, butylene-/, J-diisocyanate,
Diisocyanates such as cyclohexylene-/, J-diisocyanate, cyclohexylene-/, μm diincyanate, etc.)-"+reference', ≠"-triisocyanates such as triphenylmethane triisocyanate, toluene-J, 44.4-triisocyanate, etc. , 4! ,! '-dimethyldiphenylmethane-2.2',! ,! Tetraincyanates such as r'-tetraisocyanate, adducts of hexamethylene diisocyanate and trimethylolpropane, adducts of ≠-tolylene diisocyanate and trimethylolpropane, adducts of xylylene diisocyanate and trimethylolpropane, There are incyanate prepolymers such as adducts of tolylene diisocyanate and hexanetriol.

Examples of polyols include aliphatic and aromatic polyhydric alcohols, hydroxy polyesters, and hydroxy polyalkylene ethers. Preferred polyols include the following (I) and (II)% between two hydroxyl groups.
(III) or a polyhydroxy compound having a (Fi'l) group in its molecular structure and having a molecular weight of zooo or less.

Here, A in (IF), (III), and (W) represents a substituted or unsubstituted aromatic moiety, and the aliphatic hydrocarbon group in (I) has a basic skeleton of -〇nH2n-. , the hydrogen group may be substituted with another element.

To give a specific example, an example of (I) is ethylene glycol, l,! --f'lonoξandiol, 1, Hiro-butanediol, l, J-bentanediol, /, 6
-hexanediol%/, 7-hebutansinol, i
, r-octanediol, propylene glycol, λ,
3-dihydroxybutane.

/, cordihydroxybutane, l, 3-dihydroxybutane% λ, 2-dimethyl-1. ! -prononediol, Ko, Hiro- is tantanediol%λ,! -Hexanediol, J-)'f Roux/,! - Bentakediol, /, 4
L-cyclohexane dimetatool, dihydroxycyclohexane, diethylene glycol%'lλ, G-trihydroxyhexane, phenylethylene glycol, /
, /, /-trimethylolpropane, hexanetriol, pentaerythritol, glycerin, etc.

Examples of ('II) include condensation products of aromatic polyhydric alcohols and alkylene oxides such as l,≠-di(2-hydroxyethoxy)benzene and resorcinol dihydroxyethyl ether.

Examples of fII[) include p-xylylene glycol,
m-xylylene glycol, α, α'-dihydroxy-p-diisopropylbenzene, etc. are used.

(IVIO examples include .mu., .mu.'-dihydroxy-diphenylmethane, 2 (ri+p'-dihydroxydiphenylmethyl)benzyl alcohol, bisphenol A and ethylene oxide adducts.

Adducts of propylene oxide are examples of bisphenols. The polyol is preferably used in a proportion of hydroxyl groups of 0.02 to λ mol per 7 mol of incyanate groups.

Polyvalent incyanates can also react with water to form polymeric materials.

When making microcapsules, water-soluble polymers can be used, and the water-soluble polymers may be any of water-soluble anionic polymers, nonionic polymers, and amphoteric polymers.

As the anionic polymer, both natural and synthetic polymers can be used, and examples thereof include those having -coo, -so, groups, etc. Specific anionic natural polymers include gum arabic and alginic acid.
Semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, sulfated cellulose, and lignin sulfonic acid.

Synthetic products include anhydrous maleic oxygen (including hydrolyzed ones) copolymers, acrylic acid-based (methacrylic acid-based) polymers and copolymers, vinylbenzene sulfonic 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.

These water-soluble polymers are used as a 0.0/10 wt% aqueous solution. The particle size of the microcapsules is adjusted to 20μ or less. Generally, if the particle size exceeds 20 μm, the print quality tends to be poor.

In particular, in the case of performing knife-edge heating using a thermal head from the coated layer side, the thickness is preferably tμ or less in order to avoid pressure fog.

Any one of the diazo compound and the coupling component, which are the main components used in the present invention, is used as the core material of the microcapsule. When the two types are enriched in the core material of microcapsules, separate microcapsules may be used. Other ingredients not possessed by the core material of the microcapsules are used in the heat sensitive layer outside the microcapsules.

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

Diazo compound used in the present invention, coupling component,
If necessary, the basic substance used is ff! inside the microcapsule. Whether it is attached to the heat-sensitive layer outside the microcapsule, the coupling component is o, 1-io parts by weight based on the diazo compound/M part, and the basic substance used if necessary is 0.1 parts by weight. , 20 parts by weight. Maku diazo compound is 0.0ri ~
! .

It is preferable to apply 2/m2.

When the diazo compound, the coupling component, and the basic substance used if necessary are not microencapsulated, they are preferably used as a solid dispersion together with a p-water bathing polymer using 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 λ~jOwi%, and the diazo compound, coupling component, and basic substance are each added to this water-soluble polymer solution! It is added so that ~≠Owt%.

The dispersed particle size is preferably less than ioμ.

The heat-sensitive recording material of the present invention contains pigments such as silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide, calcium carbonate, etc., and styrene beads for the purpose of preventing stickiness and improving writing properties against the thermal head. , urea-
Fine powder such as melamine resin can be used.

Similarly, metal soaps can also be used to prevent sticking. The usage amount of these is O1
2 to 7 fi/m2, and furthermore, in the heat-sensitive recording material of the present invention, thermofusible substances can be used to increase the heat recording density.

As a heat-melting substance, it is solid at room temperature, but it has a melting point that melts when heated by thermal '\t! It is a substance with a temperature of θ to izo°C, and is a substance that dissolves a diazo compound, a coupling component, or a basic substance. Heat-melting substances are o, i, io
Dispersed in the form of particles of μ, solid content Q, λ ~ 7 ji /
m'' is used. Specific examples of the heat-melting substance include fatty acid amides, Nf-converted fatty acid amides, ketone compounds, urea compounds, and esters.

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

Binders include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester, ethylene-acetic acid. Various emulsions of vinyl copolymers can be used. The amount used is 0 solid content, j−j g/m 2 .

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 can be added.

The heat-sensitive recording material of the present invention is produced by preparing a coating liquid containing a diazo compound, a coupling component, a basic substance used as necessary, and other additives, and coating it on a support such as paper or a synthetic resin film with a bar. coating, air knife coating,
A heat-sensitive layer having a solid content of j to 21 g/m2 is provided by coating and drying by a coating method such as gravure coating, roll coating, spray coating, or dip coating. Another method is to add the coupling component, the optional basic substance, and other additives as the core material of the microcapsules, or to solidly disperse them.

Alternatively, dissolve it as an aqueous solution and then mix to make a coating solution, apply it on a support, and dry it to a solid content of 2 to 109/m2.
A coating made by providing a pre-coat layer of 2 and then adding the main component diazo compound and other additives as the core material of the microcapsules, or by dispersing them as a solid or dissolving them as an aqueous solution and then mixing them. Apply liquid, dry and solid content /~/! It is also possible to use a laminated type with a coating layer of /l/m2. In any case, it is necessary to encapsulate either the diazo compound or the coupling component in microcapsules. The layered heat-sensitive recording material may have a layered layer in the reverse order, and the coating method may include successive layering or simultaneous coating. This laminated heat-sensitive recording material exhibits particularly excellent performance in long-term storage.

The paper used for the support is heat-extracted pH 4 paper sized with a neutral sizing agent such as an alkyl ketene dimer.
- Neutral paper and Tokukaisho! Yo-142g No. 1)
It is advantageous in terms of storage stability over time.

In addition, in order to prevent the coating liquid from penetrating into the paper and to improve the contact between the recording heat head and the heat-sensitive recording layer, Japanese Patent Application Laid-Open No. 1997-1999 J7-//
4j J'7 and which has a Bekk smoothness of 0 seconds or more is advantageous.

In addition, paper with an optical surface roughness of gμ or less and a thickness of 0 to 75μ, as described in Japanese Patent Application Laid-Open No. Sho JR-I3Tμ Octopus,
A paper with a density of 0°29/cm3 or less and an optical contact ratio of 1% or more as described in ZA-6RIQRI No. 1, JP-A-Sho! t-6
Kaname described in RiQri No. 7.

A paper made from pulp that has been beaten to a standard p water content (JIS Pr12i) of 7 aootx or higher to prevent penetration of the coating liquid. JP-A-Sho! describes a paper made by a Yankee machine and uses the glossy side of Kubara paper as the coating surface to improve color density and resolution. Ta 3!
The paper described in No. 15, which has been subjected to a corona discharge treatment to improve coating suitability, can also be used in the present invention and gives good results.

In addition to these, any support commonly 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 computers that require high-speed recording, and can be fixed by exposing to light to decompose unreacted diazo compounds after thermal printing. I can do it.

In addition, "Example" which may be used as a heat transfer type copying paper Examples are shown below, but the present invention is not limited thereto.The "part" indicating the amount added is " Parts by weight.

Example 1 <3:/) of the following diazo compound i part and xylylene diisocyanate and trimethylolpronoξ
s was dissolved in 2≠ parts of diphenyl cresyl phosphate. A solution of this diazo compound is mixed with polyvinyl alcohol 3.
! 7.7 parts of gelatin is water! It was mixed with the aqueous solution dissolved in part r and emulsified and dispersed at 200C.

Add 100 parts of water to the resulting emulsion and stir while stirring.
2 hours later, a capsule liquid containing the diazo compound and having an average particle size of 3 μm was obtained.

(Diazo compound) Next, add 20 parts of λ-hydroxy-3-sectanoic acid anilide! In addition to % polyvinyl alcohol water HK/00 parts,
Dispersion was carried out in a sand mill for about 2≠ hours to obtain a dispersion with an average particle size of 3μ.

Next, 720 parts of triphenylguanidine was added to 100 parts of a % polyvinyl alcohol aqueous solution, and about 40% of the mixture was dispersed in a sand mill for a period of time to obtain a dispersion having an average particle size of 3 μm.

Furthermore, 20 parts of p-benzyloxyphenol f! % polyvinyl alcohol aqueous solution using a sand mill for about 2 hours to obtain a dispersion with an average particle size of about 3 μm.

Diazo compound capsule liquid 1 obtained as above
0 parts, 1 part of coupling component dispersion, 1 part of triphenylguanidine dispersion. Part i and p-benzyloxyphenol dispersion 30W5 were used as a coating solution.

This coating solution was applied to smooth high-quality paper (-tO, !iF/m2) using a coach-in-blonde coater with a wire bar to give a dry weight of Ill/m2, and dried at ≠00C for 30 minutes to prepare a heat-sensitive recording material. Obtained.

(Test method) The obtained heat-sensitive recording material was thermally recorded using a Gm mode thermal printer (Hifax 700; manufactured by Hitachi, Ltd.), and then a high-pressure mercury lamp (Jet Light) was used. The entire surface was exposed to light using a 2000-color (oak) needle) and fixed. The blue density of the obtained recorded image was measured using a Macbeth reflection densitometer. 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 performed again on the fixed portions, no image was recorded on any of them, and it was confirmed that they were fixed.

Next, in order to examine the raw storage stability, the skin density (surface fog) of the heat-sensitive recording material and the heat-sensitive recording material were stored in the dark for 2≠ hours under the conditions of Hiro□QC1 relative humidity and 0% RH. After performing the deterioration test, the background fog was measured using a Macbeth reflection densitometer, and changes in the background fog were observed. The results are shown in Table 1.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that tricresyl-2≠ part of phosphate was used in place of the λ≠ part of diphenylcresyl phosphate in Example. In addition, tests were conducted in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 7 instead of the diphenylcresyl phosphate λq part of Example 1
A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 2≠ parts of dibutyl tarate were used. Further, tests were conducted in the same manner as in Example 1, and the results are shown in Table 1.

"Effects of the Invention" As can be seen from Table 1, compared to Comparative Examples 1 and 2 using conventional organic solvents, Example 1 using the single organic solvent of the present invention had a higher image density, and Concentration is low. Further, even after the forced deterioration test, the concentration in the skin area was lower in the example than in the comparative example.

Claims (1)

[Scope of Claims] A heat-sensitive recording material having a heat-sensitive layer comprising a diazo compound and a coupling component, wherein at least one of the diazo compound and the coupling component is encapsulated in microcapsules together with an organic solvent, and the organic A heat-sensitive recording material characterized in that the solvent is a compound represented by the following general formula. General formula ▲ Numerical formula, chemical formula, table, etc. are available ▼ In the formula, R represents a substituted or unsubstituted aryl group.