JPS62144990A - Thermal recording material - Google Patents

Abstract

PURPOSE:To provide a thermal recording material having excellent raw preservability and a high thermal color forming property and less susceptible to lowering of recorded image density during long-time preservation after thermal recording, by incorporating at least one aliphatic amide compound in a recording layer. CONSTITUTION:A thermal recording material comprises a recording layer comprising a diazo compound and a coupling component on a base, with at least one aliphatic amide compound incorporated in the recording layer. It is preferable that either one of the diazo compound and the coupling component is incorporated in microcapsules so that, when the recording layer is heated, reactive substance in the core of the microcapsules and in the exterior of the microcapsules are brought into reaction with each other mainly through microcapsule walls. A preferable example of the aliphatic amide compound is a compound of formula RCONH', wherein R represents hydrogen, an alkyl or alkenyl.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a heat-sensitive recording material, and particularly to a fixable diazo-based heat-sensitive recording material. More specifically, the present invention relates to a heat-sensitive recording material that has excellent storage stability before thermal recording, high color density during thermal recording, and is capable of light fixing after thermal recording.

"Prior Art" A leuco coloring type heat-sensitive recording material is usually used as a recording material used in a heat-sensitive recording method. However, this heat-sensitive recording material has the disadvantage that color develops in unexpected places due to harsh handling after recording or adhesion of heated dust or solvents, staining the recorded image. In recent years, research on diazo coloring type heat-sensitive recording materials has been actively conducted as a heat-sensitive recording material free from such drawbacks. For example, JP-A-57-/,
2JOI No. 6, Journal of the Institute of Image Electronics Engineers, //, Kota 0(1?t
2), etc., thermal recording is performed on a recording material using a diazo compound, a coupling component, and a basic component (including substances that become basic when heated), and then light irradiation is performed to detect unreacted components. It decomposes the diazo compound and stops color development.

It is true that this method makes it possible to completely stop color development (hereinafter referred to as fixing) in areas that do not require recording.

However, this recording material also undergoes gradual pre-coupling during storage, and undesirable coloring (fogging) may occur. For this purpose, attempts have been made to prevent all contact between the components and prevent pre-coupling by making any seven of the color-forming components exist in the form of discontinuous particles (solid dispersion). Preservability of materials (hereinafter referred to as raw shelf life)
However, it still has the drawback of not being sufficient, and that the thermal coloring property is reduced. As another measure, it is known to separate the diazo compound and the coupling component into completely separate layers in order to minimize contact between the components (for example, the above-mentioned Japanese Patent Application Laid-Open No. 37-1998)
123016). Although this method improves raw storage stability, the thermal coloring properties are greatly reduced, and it cannot respond to high-speed recording with short pulse widths, making it impractical. Furthermore, 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 (JP-A-17-4 (No. 4C/4C/, JP-A-Sho!). 7-
No. 7 Hiro 263), hydrophobic polymer substances (I! # Kaisho 7
It is known to isolate it from other fractions by encapsulating it with 7-/929μ≠.

However, these encapsulation methods involve dissolving wax or polymeric substances in their solvents, and forming capsules by dissolving or dispersing all of the coloring components in the solution, with a shell surrounding the core material. This is different from the concept of a normal capsule covered with water.

For this reason, when the coloring component is dissolved and formed, the coloring component does not become the core material of the capsule, but mixes uniformly with the encapsulating material, and pre-coupling gradually progresses on the outer surface of the capsule wall during storage. Raw storage stability is not fully satisfied. In addition, when a color-forming component is dispersed and formed, the color-forming reaction does not occur unless the capsule wall is thermally melted, resulting in a decrease in thermal color-forming properties. Furthermore, there is a manufacturing problem in that the solvent used to dissolve the wax or polymer substance must be removed after the capsules are formed, and this method is not completely satisfactory.

Therefore, in order to solve all of these problems, there is a method in which at least one of the components involved in the color reaction is contained in a core material, and a wall is formed around this core material by polymerization to form a microcapsule. Jet-410≠3 specifications)
We have discovered an excellent heat-sensitive recording material.

``Problems to be Solved by the Invention'' However, even with heat-sensitive recording materials made using this microencapsulation method, the optical density of the image-recording area may apparently decrease due to long-term storage after heat recording, and further improvement is required. was desired.

``Object of the Invention'' Therefore, the first object of the present invention is to provide a heat-sensitive recording material that has excellent raw storage stability, high thermochromic property, and less decrease in recorded image density during long-term storage after thermal recording. There is a particular thing.

A second object of the present invention is to provide a heat-sensitive recording material that can be fixed by photodecomposing unreacted diazo compounds after heat recording.

A third 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 in which a recording layer containing a diazo compound and a coupling component is coated on a support, at least an aliphatic amide compound is added. The problem was solved by a heat-sensitive recording material characterized by containing one or more types of heat-sensitive recording materials in the recording layer.

Note that either the diazo compound or the coupling component is preferably contained in microcapsules.

The microcapsules of the present invention are destroyed by heat or pressure, as used in conventional recording materials, and color is developed by bringing the reactive substance contained in the core of the microcapsule into contact with all the reactive substances outside the microcapsule. It does not cause a reaction, but rather reacts by mainly permeating through the microcapsule wall tube by heating all of the reactive substances present in the core and outside of the microcapsule.

As a result of intensive research into heat-sensitive recording materials using such microcapsules, the present inventors have found that they have excellent raw storage stability, good thermochromic properties, and improve the optical density of recorded images during long-term storage after heat recording. In order to eliminate the drop, it has been found that it is extremely effective to include an aliphatic amide compound in the layer in addition to the diazo fraction and coupling component.

Preferred examples of the aliphatic amide compound in the present invention include compounds represented by the following general formula (I).

That is, in the above formula, R represents a hydrogen atom, an alkyl group, or an alkenyl group.

Furthermore, substituents such as a halogen atom, an acyl group, an oxa group, a thioxa group, an alkoxy group, an aryloxy group, a sulfo group, a carbonato group, an alkoxycarbonyl group, an aryl group, a hydroxy group, a sulfamoyl group, a carbamoyl group, an aryloxycarbonyl group, At least one of an amino group, a substituted amine group, an acylamino group, an alkanesulfonyl group, an arylsulfonyl group, a cyan group, and an acyloxy group may be substituted. R' is a hydrogen atom, a halogen atom, a hydroxy group, or an alkoxy group. represents an alkyl group, an alkenyl group, or any of these groups which may have a substituent group. Among these, the melting point
Amide compounds having a total number of carbon atoms of 2j or less are preferred from the viewpoint of ease of handling and availability.

Specific examples of R include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an allyl group, a dimethylbutyl group, a t-amyl group,
Hexyl group, isoamyl group, cyclohexyl group, cyclohexylmethyl group, chloro atom, methylcyclohexyl group, chloroethyl group, β-acetoxyethyl group, 3-ketobutyl group, benzyl group, α and β-phenethyl group, vinyl group, methoxy group, Thiomethoxy group, ethoxy group, propoxy group, butoxy group, hydroxy group, diethylamino group, butylamino group, butoxycarbonyl group, ethylhexyloxycarbonyl group, N-hexylcarbamoyl group, β-acetoxyethoxy group, hydroxyethoxy group, phenoxy7ethyl group, λ-chlorophenoxycomethylethoxy group, dichlorophenoxy group, dichlorophenyl group, trimethylphenethyl group, amine group, nitro group, ethoxysulfonylethyl group, phthoxysulfonylprobyl group, ethoxycarbonylpropyl group group, butoxyethyl group, phenoxyprobyl group, β-phenoxybutyl group, β-methacryloxyethyl group, isobutyl group,
n-octyl group, arylamino group, chloroanilino group,
Thiophenoxy group, t-octyl group, cetyl group, phenylpropyl group, dodecyl group, p-methoxycinnamyl group, carbonatobutyl group, styryl group, β-su, methylmethyl group, benzyl group, cyclopropyl group, p -Chlorobenzyl group, methylbenzyl group, inpropylbenzyl group, m-chlorobenzyl group, vinylbenzyl group, carbamoylbutyl group, carbamoyloctyl group, ethoxyhexyl group, chloropropyl group, phenoxybutyl group, benzoylpropyl group, morpholinoethyl group group, naphthoylbutyl group, 0-ethoxycarbonylbenzyl group, β-thiophenoxyethyl group, β-anilinoethyl group, β-benzoylaminoethyl group, β-λ-ketocarbonyl group, β
-acetylaminoethyl group, Hiro-ketohexyl group, γ-
Examples include oxabutyl group, γ-butoxypropyl group, ethoxybenzyl group, and p-methoxybenzyl group.

Examples of R' include formyl group, acetyl group, methanesulfonyl group, benzoyl group, benzenesulfonyl group, methyl group, ethyl group, isopropyl group, benzyl group, hydroxy group, methoxy group, acetoxy group, β-ethoxyethyl group, etc. be. R and R' are mutually bonded! It may form a negative to r-membered ring. Among these FLSR' combinations, the solubility in water is the highest! Below, preferably O0! The following compounds are conveniently available.

When retaining an aliphatic amide compound as dispersed particles in a recording material, crystalline amides, especially melting point! OeaC
Or 200'C, good! L< is 7j″C or ty
Compounds with z"c are preferred, especially 1.
It is preferable that the weight loss rate when held for 1 minute is 1 ozb or less.

Specific examples include the following:

Oleic acid amide, propionamide, malonamide,
Phenylurea, sebacinamide, phenylacetamide, cinnamic acid amide, α-methylcinnamic acid amide, phenylpropionamide, β-chloropropionamide, O-
Methoxyphenoxyacetamide, p-ethoxyphenoxyacetamide, p-methoxyphenoxyacetamide, chlorophenylacetamide, O-methoxyphenylacetamide, capronamide, methoxyphenylpropionamide, phenylpropionate amidoxime, N-formyl-phenylpropion Amide, methylcyclohexylcarbonylamide, dodecylamide, phenoxyacetamide, naphthylformamide, benzylformamide, β-naphthoylpropionamide, phenylpropionamide, p-ethylphenylacetamide, naphthylpropionamide, methyl-2-toluamide, benzoylbutyl Amide, biphenylpropionamide, naphthylacetamide, picolinamide, β-su7toxybutyramide, m-methoxyphenylacetamide, m-ethoxyphenylpropionamide, N-formylphenylacetamide, phenoxyethoxypropionamide, Thia e
- Includes caprolactam.

Among these, compounds having at least one aromatic ring are preferred.

The diazo compound used in the present invention has the general formula ArN20X (wherein, Ar represents an aromatic moiety, N2+ represents a diazonium group, and X- represents an acid anion).
It is a diazonium salt represented by n, which can develop a color by causing a coupling reaction with a coupling component, and is 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 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, an aryloxy group, an arylamino group, or a halogen (l, Br+, F). n represents l or 2.

Substituted amine groups for Y include monoalkylamino groups, dialkylamino groups, arylamino groups, morpholif groups,
A piperidino group, a pyrrolidino group, etc. are preferred.

Specific examples of diazonium that forms salts include ≠-thiazo/-dimethylaminobenzene, ≠-diazo/-diethylaminobenzene', ≠-thiazo/-dipropylaminobenzene, ≠-diazo/-methylbenzylaminobenzene, Hiro- Diazo-7-dibenzylaminobenzene, μm diazo-/-ethylhydroxyethylaminobenzene, diazo-7-diethylamino-3-methoxybenzene, Hiro-diazo-l-dimethylamino-2-methylbenzene, ≠-diazo-7 -penzoylaminoko,
! -jethoxybenzene, arrow-diazo-l-morpholinobenzene, ≠-diazo/-morpholino 21! -Jethoxybenzene, Hiro-diazo-7-morpholino-2,!
-dibutoxybenzene, Hiro-diazo-7-anilinobenzene, ≠-diazo/-tolylmercapto-2,! −
Jetoxybenzene, ≠-diazo/ , 4'-methoxybenzoylamino-2,j-jethoxybenzene,
Gudiazo-7-pyrrolidino-λ-ethylbenzene and the like can be mentioned.

Specific examples of acid anions include CnF2n+IC0O-
(n is an integer from 1 to ri), CmF2m+1so3 (m is an integer from /-4), (CAi"21+l5Oz)2CH(
l is an integer of 1 to /l), HC(CHa)a (n is an integer of 7 to 1), B F 4 + PF 6-, and the like.

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

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

C4H9 C(CHa)a C2H5 C4H9 0C4H.

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, and specific examples include resorcinol, phloroglucin, and λ.

Sodium 3-dihydroxynaphthalene-6-sulfonate, /-hydroxy-2-naphthoic acid morpholinopropylamide, /, j-dihydroxynaphthalene, 2,3-
Dihydroxynaphthalene, 2゜3-dihydroxy-6-
Sulfanylnaphthalene, cohydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3-
Naphthoic acid anilide, 2-hydroxy-3-naphthoic acid-λ'-methylanilide, λ-hydroxy-3-naphthoic acid ethanolamide, co-hydroxy-3-naphthoic acid octylamide, λ-hydroxy-3-naphthoic acid-
N-dodecyl-oxy-propylamide, λ-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide, l-phenyl-3-methyl-! -pyrazolone, /-(
2', Hiro'6'-trichlorophenyl)-3-benzamide-yo-pyrazolone, /-(J', ≠/, tl
) Lichlorophenyl)-3-anilino-y-pyrazolone, l-phenyl-3-phenylacetamide-y-
Examples include pyrazolone. Furthermore, by using two or more of these coupling components in combination, it is possible to obtain an image of any desired color tone.

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 basic substances that are poorly water-soluble or water-insoluble, and substances that generate alkali when heated. 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, and triazoles. Examples include nitrogen-containing compounds such as lysines, amidines, formazines, and pyridines. Specific examples of these include ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine,
Stearylamine, allyl urea, thiourea, methyl urea, allyl thiourea, ethylene thiourea, cobenzylimidazole, Hiro-phenylimitasol, cophenylu≠-methyl-imidazole, 2-undecyl-imidacillin, λ,≠,! - triflyleucoimidazoline,
l.

Cordiphenyl-μ, France-dimeteru-co-imidazoline, 2-phenyl-co-imidazoline, l.

λl J l'! J phenylguanidine, N, N'
-phenylstyrylamidine, N,N'-phenylphenylamidine, /lλldilylguanidine, /,
, 2-dicyclohexylguanidine, /, 2°J −)
IJ cyclohexylguanidine, quanisine trichloroacetate, N,N'-dibenzylpiperazine, μ, 3'-dithiomorpholine, morpholinium trichloroacetate, co-aminopenzothiazole, 2-penzoylhydrazino-pensothiazole be. Two or more of these basic substances can also be used in combination.

In the present invention, a reactive substance contained in the core substance of a microcapsule is dissolved or dispersed in a water-insoluble organic solvent, and after emulsification, a microcapsule wall is formed around it by polymerization. The boiling point is preferably .

Specifically, phosphoric acid esters, heptatalic acid esters and other carboxylic acid esters, fatty acid amides, alkylated hypohenyls, alkylated terphenyls, chlorinated norafins,
Alkylated naphthalenes, diarylethanes, etc. are used. Specific examples include tricresyl phosphate, trioctyl phosphate, octyldiphenyl phosphate, dibutyl tricyclohexylphthalate, dioctyl heptathalate, dilauryl phthalate, dicyclohexyl phthalate, phther oleate, diethylene glycol dibenzoate, dioctyl sepacate, Dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyltriethyl citrate, octyl maleate, dibutyl maleate, isopropylbiphenyl, inamyl biphenyl, chlorinated paraffin, diisopropylnaphthalene, /,
/'-ditolylethane, 21 μm ditertiary aminophenol, N,N-dibutyl-λ-butoxy-5-tertiary octylaniline, and the like.

Among these, ester solvents such as didutyl phthalate, tricresyl phosphate, diethyl phthalate, and dibutyl maleate are particularly preferred.

The inventive microcapsules are made by emulsifying a core material containing a reactive substance and then forming a wall of polymeric material around the oil droplets. A reactant forming a polymeric substance is added to the interior of the oil droplet and/or to the exterior of the oil droplet. Specific examples of polymeric substances include polyurethane, polyurea,
Polyamide, polyester, polycarbonate, urea
formaldehyde resin, melamine resin, polystyrene,
Examples include 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 polyurethane, polyurea, polyamide, polyester, polycarbonate, and more preferred are polyurethane and polyurea.

The microcapsule wall of the present invention is particularly effective when using a microencapsulation method by polymerizing a glue actant from inside an 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.

This method and specific examples of compounds are described in U.S. Patent J.
, 724. It is described in the specifications of No. fOv, No. 3,7 A, and No. j62.

For example, when polyurethane is used as a capsule wall material, a polyvalent isocyanate and a second substance (such as a polyol) that reacts with it to form the capsule wall 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 to be used and the polyol and polyamine to be reacted with it, US Pat. No. 321r/JI3, US Pat. , same≠2-2
No. 44112, JP-A-P, R-ROIY1, Mukai at-
rttort, and all of them can also be used.

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

In particular, it is preferable to use polyvalent insia-ol 1-1 as the first wall-forming substance and polyol as the second wall-forming substance because of good shelf life. Furthermore, by adjusting both 'Icm', the thermal permeability of the reactive substance can be changed arbitrarily.

Examples of the polyvalent isocyanate which is the first wall-forming substance include m-phenyl diisocyanate, p-p-phyl diisocyanate, 2,6-tolylene diisocyanate, 2. μ-tolylene diisocyanate, naphthalene-7, diisocyanate, diphenylmethane, 3'-diisocyanate, 3.3'-dimethoxy-hiro, hiro'-biphenyl diisocyanate, j,
J'-Dimethyldiphenylmethane-Hiro, Hiro'-diisocyanate, xylylene-7,≠-diisocyanate, 4t, 4A'-diphenylprono-ξ-diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1, λ-diincyanate, butylene -7,2-diisocyanate, cyclohexylene-/,! -diisocyanate, cyclohexylene-/, diisocyanate such as Hiro-diisocyanate,
p, p',≠"-triphenylmethanetriinocyanate, toluene=2,≠, triinocyanates such as 6-dolyisocyanate, Hiroshi, 3'-dimethyldiphenylmethane-co, 2', ni, Z'-tetra Tetraincyanates such as incyanate, adducts of hexamethylene diisocyanate and trimethylolpropane, 2.I
A-) There are incyanate prepolymers such as adducts of lylene diisocyanate and trimethylolpropane, adducts of xylylene diisocyanate and trimethylolpropane, and adducts of tolylene diisocyanate and hexanetriol.

The polyol, which is the second wall-forming substance, includes aliphatic and aromatic polyhydric alcohols, hydroxy polyesters,
There is something called hydroxy polyalkylene ether. Preferred polyols include polyhydroxy compounds having the following group (11, (II), (1), or (IV)) in the molecular structure between two hydroxyl groups and having a molecular weight of not more than zoooo.

(1) Aliphatic hydrocarbon group (fV) with carbon number λ to t
-0-Ar-C-Ar -0-wherein (II),
Ar in (nl) and (IV) represents a substituted or unsubstituted aromatic moiety, and the aliphatic hydrocarbon group in (1) is
CnH2n has a basic skeleton, and hydrogen groups may be substituted with other elements.

Specifically, examples of (1) include ethylene glycol, 7.3-propanediol, 1≠-butanediol, 1lj-butanediol, /, 4-hexanediol, /, 7-hebutansinol, r-octanediol, propylene glycol, 3-dihydroxybutane.

l, 2-dihydroxybutane, /, J-dihydroxybutane, λ, cordimethyl-/, 3-propanediol,
λ, Hiro-pentanediol, 2. ! -hexanediol, 3-methyl-7lj-bentanediol, /, 4A-
Cyclohexane dimetatool, dihydroxycyclohexane, diethylene glycol, /, 2.4-)! J Hydroxyhexane, phenylethylene glycol, /, /
, /-trimethylolpropane, hexanetriol,
Erythritol, glycerin, etc. are recommended.

Examples of (n) include condensation products of aromatic polyhydric alcohols and alkylene oxides such as /, 4C-di(λ-hydroxyethoxy)henyne, and resorcinol dihydroxyethyl ether.

Examples of (nl) include p-xylylene glycol, m
-xylylene glycol, α, α′-dihydroxy-p
-diisopropylbenzene, etc.

Examples of MV) are 44, 4! Examples include '-dihydroxy-diphenylmethane, 2-(p,p'-dihydroxydiphenylmethyl)benzyl alcohol, an adduct of ethylene oxide to hisphenol A, and an adduct of propylene oxide to bisphenol A.

The polyol is preferably used in a ratio of 0.02 to 2 moles of hydroxyl groups per mole of isocyanate groups.

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.

Examples include those having -〇〇-1-803 groups. Specific anionic natural polymers include gum arabic and alginic acid, and semi-chemical products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, and sulfated cellulose.

These include lignin sulfonic acid.

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

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 0.07 to 10 wt% aqueous solution. The particle size of the microcapsules is adjusted to 20μ or less. Generally, if the particle size exceeds 0μ, the print quality tends to be poor.

In particular, when heating with a thermal head is performed from the coated layer side, it is preferable that the thickness be less than r[mu] to avoid pressure fog.

Of the diazo compound, the coupling component, and the basic substance used as necessary, which are the main components used in the present invention, any seven of them are used as the core material of the microcapsule, or two of them are used. Alternatively, three types can be used. When two types are contained in the core material of microcapsules, they may be the same microcapsule or 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 the microcapsules are used in the heat-sensitive layer outside the microcapsules.

The uninvented aliphatic amide compound may be present in the core of the microcapsule or outside.

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,
The basic substance used as necessary may be contained in the inside of the microcapsule or in the heat-sensitive layer outside the microcapsule, and the coupling component may be o, i to 1 with respect to 1 part by weight of the diazo compound. /Q heavy ring part It is preferable to use the heavy ring part substance in a proportion of o, i to co0 parts by weight. Also, diazo compounds are 0,0! -j, Ot
/m 2 coating is preferred.

When the diazo compound, coupling 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.

At this time, the concentration of water-soluble polymer is 2 to 30 wt%,
Add the diazo compound, coupling component, and basic substance to this water-soluble polymer solution, respectively! 〜≠Put it in so that it is even.

The dispersed particle size is preferably less than IOμ.

A hydroxy compound, a carbamate ester compound, an aromatic methoxy compound, an organic sulfonamide compound, or an aromatic amide compound can be added to the heat-sensitive recording material of the present invention for the purpose of further improving thermal color development. It is believed that these compounds 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.

Specific examples of hydroxy compounds include pt-butylphenol and pt-octylphenol.

p-α-cumylphenol p-i-<methylphenol, m-xylenol, 2. j-dimethylphenol,
λ,≠,! r-t+) methylphenol, 3-methyl-
Hiro-isopropylphenol, p-benzylphenol, 0-cyclohexylphenol, p-(diphenylmethyl)phenol, p-(α,α-diphenylethyl)phenol, 0-phenylphenol% p-hydroxybenzoethyl phenol , chloropyr p-hydroxybenzoate.

p-hy)'butyl p-hydroxybenzoate, hensyl p-hydroxybenzoate, p-methoxyphenol, p-methoxyphenol, p-hebutyloxyphenol, p-benzyloxyphenol, dimethylvanillin 3-hydroxyphthalate, /, l-bis(Hiro-hydroxyphenyl)
dodecane, /, /-his(Hiro-hydroxyphenyl)-
Coethylhexane, /, l-bis(≠-hydroxyphenyl)-2-methyl-pentane, λ, 2-bis(Hiro-?:)'roxyphenyl)-hebutane vanillin, λ-
ti-thiru≠-methoxyphenol, 2°t-dimethoxyphenol, 2. ．． 2'-dihydroxy-Hiroshi-
Phenolic compounds such as methoxybenzophenone, 2.
1-dimethyl-2,! -Hexanediol, resorcinol di(cohydroxyethyl)ether, resorcinol mono(cohydroxyethyl)ether, salicyl alcohol, t,ti-(hydroxyethoxy)benzene, p-xylylene diol, /-phenyl-7,2
-ethanediol, diphenylmethanol, 1. /-diphenylethanol, 2-methyl-λ-phenyl/,
J-floc/diol, λ,6-cyhydroxymethyl-p-cresol benzyl ether, 2. t-dihydroxymethyl-p-cresol benzyl ether,! −(
Examples include alcohol compounds such as o-methoxyphenoxy)-/, 2-i lopanediol, and the like. Specific examples of 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. can be mentioned. Specific examples of aromatic methoxy compounds include λ-methoxybenzoic acid, 3. j-dimethoxyphenylacetic acid, λ-methoxynaphthalene-'t3s! -trimethoxyhensen, p-dimethoxybenzene, p-benzyloxymethoxybenzene, 1. Examples include cordiphenoxyethane.

These compounds can be used by making microcapsules together with the core material of the microcapsules, or by being added to the coating solution of the heat-sensitive recording material and existing outside the microcapsules. is preferred. In any case, the amount used is 0.07 to 70 parts by weight, preferably 0.17 to 5 parts by weight, based on the coupling component/part by weight, but it may be selected as appropriate to adjust the desired color density. good.

The heat-sensitive recording material of the present invention includes a free radical generator (a compound that generates free radicals when irradiated with light) used in photopolymerizable compositions for the purpose of reducing yellowing of the background after photofixing. can be added. Examples of free radical generators include aromatic ketones (e.g., benzophenone, <4'-bis(dimethylamino)benzophenone, ≠, 3'-bis(diethylamino)benzophenone, μm methoxy-μ'(dimethylamino)benzophenone, 4(,!'-dimethoxybenzophenone, dimethylaminobenzophenone, μm methoxy-3,3'-dimethylbenzophenone, l-hydroxycyclohexyl 7enyl ketone, ≠-
Dimethylaminoacetophenone, λ-methyl/-[Hiro-(methylthio)phenyl-2-morpholino-propanone-7-acetophenone, benzyl), cyclic aromatic ketones (e.g., fluorenone, anthrone, xanthone, thioxanthone, λ-chlorothioxanthone) ,λ,
4! - Dimenalthioxane I-N, 29 μm diethylthioxanthone, acridone, N-ethyl acridone.

benzanthrone), quinone rA (e.g., benzoquinone, λ+j+j)'dimethyl-6-promobenzoquinone, 2,6-di-n-decylbenzoquinone, /
, ≠-naphthoquinone, 2-impropoxy-/, Hirosu 7-toquinone, /, 2-naphthoquinone, anthraquinone,
2-chloro-anthraquinone, 2-methylanthraquinone, 2-tert-butylanthraquinone, phenanthraquinone), benzoin, benzoin ethers (e.g. benzoin methyl ether, benzoin ethyl ether, λ).

azo compounds (e.g. azobisisobutyronitrile, α-azo -l-cyclohexanecarbonitrile, azobisvaleronitrile), organic disulfides (e.g., thiuram disulfide), and acyloxime esters (e.g., benzyl-(0-ethoxycarbonyl)-α-monoxime). .

The amount to be added is based on the diazonium compound/part by weight.
Free radical generator 0,0/~! Parts by weight are preferred. More preferably 0. /-/ parts by weight.

By encapsulating the free radical generator together with the diazonium salt as the core material of the microcapsule, the above-mentioned yellowing of the background after photofixing can be reduced.

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. A vinyl monomer is a compound that has at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.) in its chemical structure, and is a compound that has at least one ethylenically unsaturated bond (vinyl group, vinylidene group, etc.), and is a compound that contains monomers, prepolymers, λ-mers, trimers, and other It has chemical forms such as 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 the proportion is /-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 (
Although part or all of the organic solvent used as a vinyl monomer (or a dispersion medium) can be replaced with a vinyl monomer, 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, by incorporating a coupling reaction deactivator outside the microcapsules, the diazo compound present in the aqueous phase and the diazo compound in the incomplete capsules can be removed. (i.e., the diazo compound that is not completely blocked by the capsule wall) and the coupling reaction quencher react, and the diazo compound reacts with the coupling reaction (coloring reaction).
ability to be lost and fogging can be prevented.

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

Specifically, hydroquinone, sodium bisulfite,
Examples include potassium nitrite, hypophosphorous acid, stannous chloride, and formalin. In addition to this, H.

r'rhe Aromatic by Sawn ders
Diaz.

-Compounds and Their Te
chnicalApplicationsJ M, C,
tM,A.

(Cant ab, )B, Sc, (London)/
You can also choose from those published in P#P, pages 10r to 306.

The coupling reaction quenching agent is preferably one that has little coloring itself and has few side effects. More preferably, it is 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.
The deactivator is used in an amount of 1 to 2 moles per mole. More preferably, it is used in a 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 can be used by adding a coupling agent or a basic substance to a dispersed liquid or a mixture thereof. Preferably, the quencher is used in the form of an aqueous solution.

The heat-sensitive recording material of the present invention contains silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide,
Pigments such as calcium carbonate, fine powders such as styrene beads, urea-melamine resin, etc. can be used.

Similarly, metal soaps can also be used to prevent sticking. The usage amount of these is 0,
2~yy/m2.

Furthermore, a heat-melting substance can be used in the heat-sensitive recording material of this shield in order 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 j0 to /j00c that melts when heated by a thermal head, and is a substance that dissolves a diazo compound, a coupling component, or a basic substance. Thermal melting substances are 0, 7-70
It is used in an amount of 0.2 to 7 y/m2 of solids by dispersing it in the form of microscopic particles. 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 with a suitable binder.

Binders include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinyl♂rolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester, ethylene-vinyl acetate. Various emulsions of copolymers can be used. The amount used is solid content O,S~3F/7X2.

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 the main components of a diazo compound and a coupling component, as well as basic substances and other additives, and applying the coating liquid onto a support such as paper or a synthetic resin film. Apply by coating methods such as blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, etc., and dry it to reduce the solid content. ~
A heat sensitive layer of 2191/WL2 is provided. Another method is to add the main components of the coupling component, basic substances, and other additives as the core material of microcapsules, or to disperse them as solids, or to dissolve them as an aqueous solution and then mix them to form a coating solution. Prepared, coated on a support, dried to form a precoat layer with a solid content of λ ~ 10P/wL2, and further added the main component diazo compound and other additives as the core material of the microcapsule. The coating liquid is made by dispersing it as a solid or dissolving it as an aqueous solution and then mixing it, and then it is dried to reduce the solid content to 1~/! 2
It is also possible to use a laminated type with seven coating layers. The laminated type heat-sensitive recording material may have a reverse order of lamination, and the coating method may be sequential coating or simultaneous coating of the laminated layers. This laminated type heat-sensitive recording material exhibits particularly excellent long-term shelf life.

Also special request on the support! It is also possible to apply the heat-sensitive layer after providing the intermediate layer described in the Specification of Patent No. 177 Otsu No. 6.

The paper used as the support is a thermally extracted pH 4 paper sized with a neutral sizing agent such as an alkyl ketene dimer.
- Neutral paper (described in JP-A-Sho!!-/≠λ♂1)
Fully written information is advantageous in terms of storage stability over time.

In addition, in order to completely 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, JP-A-Shojt7-//
It is advantageous to use paper that is described in Otsu No. 7 and has a Beck smoothness of 0 seconds or more.

Tokukai Akira again! r-1Jtlfi? Paper having an optical surface roughness of tμ or less and a thickness of lIo to 7jμ as described in No. 2, and a paper having a density of 0°? as described in JP-A No. 1. /an
or less and the optical contact rate is /! Canadian Standard Water Intensity (JI) described in Japanese Patent Application Publication No.
S Plr/21) aoocr: Paper made from the pulp that has been beaten as above and prevented from soaking in the coating liquid, the gloss of the base paper made by a Yankee machine as described in JP-A-111-TJT Riyo No. JP-A-5'-3, which improves color density and resolution by using the surface as a coating surface! Rit!
The paper described in No. 1, in which the base paper is subjected to a corona discharge treatment to improve its 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 thermal 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 it to light after heating and decomposing unreacted diazo compounds. can. In addition, it can also be used as a heat-developable copying paper.

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

"Examples of the invention" Example 1 The following diazo compound 3. ≠ and (3:/) adduct of xylylene diisocyanate and trimethylolpropane i
Part t was added to a mixed bath medium of 24 A parts of tricresyl phosphate and 5 parts of ethyl acetate and dissolved.

The solution of this diazo compound was mixed with polyvinyl alcohol 3,
2 parts dissolved in 31 parts water, mixed into an aqueous solution, 2 parts
Emulsified and dispersed at 0C, with an average particle size of 2. An emulsion of jμ was obtained.

Add 100 parts of water to the obtained emulsion and boil it while stirring.
After 2 hours, a capsule liquid containing the diazotized adduct in the core material was obtained.

(Diazo Compound) Next, 10 parts of 2-hydroxy-3-naphthoic acid anilide and 10 parts of triphenylguanidine! The mixture was added to 100 parts of an aqueous solution of tipolyvinyl alcohol and dispersed in a sand mill for about 2≠ hours to obtain a dispersion of the coupling component and triphenylguanidine with an average particle size of 3 μm.

Further, 20 parts of α-toluamide were added with 10 parts of a μ-tivolivinyl alcohol aqueous solution and 10 parts of water and dispersed for 2 hours using a paint shaker to obtain a dispersion of α-toluamide having an average particle size of 3 μm.

Capsule liquid of diazo compound obtained as above 5
A coating liquid was prepared by adding the coupling component, 2 parts of a triphenylguanidine dispersion, and 2 parts of an α-toluamide dispersion to 0 parts. Pour this toilet cloth liquid onto smooth high-quality paper (jOr/
dry weight lO1/1 using a coating par
It was coated so as to have rL2 and dried for 30 minutes at 2j0C to obtain a heat-sensitive material.

Example λ A thermosensitive recording material was obtained in the same manner as in Example 1, except that phenoxyacetamide was used in place of α-toluamide in Example.

Example 3 A heat-sensitive recording material was obtained in the same manner as in Example 1, except that caprylamide was used instead of α-toluamide in Example 1.

Example 1 except that it does not contain any α-toluamide in Example 1.
A heat-sensitive recording material was obtained in the same manner as above.

(Test method) Heat recording was performed on the obtained heat-sensitive recording material using a Gut mode thermal printer (Hifax 700; manufactured by Hitachi, Ltd.), and then Riccobee Sue, O-Dry 100 (
+) manufactured by Koh α@)'t- was used to expose the entire surface to light and fix it. 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. All the results are shown in Table 1. On the other hand, when thermal recording was performed again on the fixed portions, it was confirmed that the images were fixed without being recorded.

Next, in order to examine raw storage stability, we checked the background density (fog) of the heat-sensitive recording material, and then stored the heat-sensitive recording material in a dark place for 2 hours at a relative humidity of ≠00C1 and 20% FLH to perform a forced deterioration test. Fog was measured using a Macbeth reflection densitometer to observe changes in fog.

Next, in order to investigate the decrease in optical density of the colored part due to long-term storage after thermal recording, the recorded image of the thermal recording material was
o Stored in the dark under 0C conditions for 76 hours and forced deterioration 72
The degree of decrease in the density of the recorded image after 11 recordings was completely evaluated.

The results are shown in Table 1.

Claims (1)

[Claims] 1. A heat-sensitive recording material comprising a recording layer containing a diazo compound and a coupling component coated on a support, the recording layer containing at least one aliphatic amide compound.