JPS6154980A - Thermal recording material - Google Patents

Abstract

PURPOSE:To prevent the yellowing phenomenon of the base of a thermal recording material after being fixed by light as well as raise the thermally color-forming property and fixability of the recording material by interposing an intermediate layer composed of an inorganic pigment and/or organic pigment having less than a given apparent specific gravity and a film-forming polymer binder between a supporter and a thermal color-forming layer. CONSTITUTION:In a thermal recording material having a thermal color-forming layer composed of micro capsules incorporated with a diazo compound and a coupling component, an intermediate layer composed of an inorganic pigment (a) of an apparatus specific gravity of 0.7g/cm<3> or less and/or an organic pigment (b) and a film-forming polymer binder is provided between the supporter and the thermal color-forming layer. The thermal recording material may be used as printing papers for facsimile and electronic computers for high-speed recording. The thermal recording material is exposed to light after being thermally printed to decompose unreacted diazo compound for fixation.

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 heat-sensitive recording material. More specifically, the present invention relates to a heat-sensitive recording material that has excellent storage stability before heat recording, high color density during heat recording, and little yellowing of the background.

"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, heating, or adhesion of solvents after recording, which stains the recorded image. 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, JP-A-Sho r7-/2
Issue 30, Journal of the Institute of Image Electronics Engineers, Mu/, 2:00 (/ri JJ
), 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 remove unreacted components. It decomposes diazo compounds and stops color development.

Indeed, according to this method, it is possible to stop color development (hereinafter referred to as fixing) in areas that do not require recording.

However, this recording material may also undergo gradual pre-coupling during storage, resulting in undesirable coloration (capri). For this purpose, any seven of the color-forming components must be present in the form of discontinuous particles (solid dispersion), and contact between the components must be prevented to prevent pre-coupling. , Preservability of marking materials (hereinafter referred to as raw preservation)
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 as separate layers in order to minimize contact between the components (for example, the above-mentioned Japanese Patent Application Laid-Open No. 67-1989-1).
/, 23θ♂≦). 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 of increasing both raw storage stability and thermochromic property by 6°4, either the coupling component or the basic substance is mixed with a non-polar waxy substance (JP-A-Sho! 7-Guda/G/No., JP-A-Show! !7-
/4t2Otsu3Otsu No.) or by encapsulating it with a hydrophobic polymer substance (4'! Kaisho!7-/Takotafta No.)) to isolate it from other components.

However, these encapsulation methods involve dissolving wax or polymeric substances in their solvents, and dissolving or dispersing the color-forming ingredients in these solutions to form capsules. This is different from the concept of a normal capsule covered with water. For this purpose, 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 during storage at the wall interface of the capsule. 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, the manufacturing problems of having to remove the wax or the solvent used to dissolve the polymeric substance after forming the capsules are 1) unsatisfactory;

Therefore, in order to solve these problems, there is a method in which at least /filt of the components involved in the coloring reaction is contained in a core material, and a wall is formed around this core material by polymerization to form a microcapsule. An excellent heat-sensitive recording material was discovered using the TA♂-4104t3 paper.

``Problems to be Solved by the Invention'' However, even with heat-sensitive recording materials produced by this microencapsulation method, there are problems such as insufficient color density during heat recording or yellowing of the background after fixing. Ta.

Therefore, a first object of the present invention is to provide a fixable heat-sensitive recording material with high thermochromic properties.

A first object of the present invention is to provide a heat-sensitive recording material in which yellowing of the background area after photofixing is prevented.

"Means for Solving the Problems" The present inventors have conducted intensive research to solve these problems, and as a result, we have developed a heat-sensitive film consisting of microcapsules encapsulating a diazo compound and a coupling component on a paper support. In a heat-sensitive recording material provided with a color-forming layer, there is a gap between the support and the heat-sensitive color-forming layer (a) apparent specific gravity o, 797 cm;
The above drawbacks have been solved by interposing an intermediate layer consisting of 3 or less inorganic pigments and/or organic pigments and (b) a film-forming polymer binder.

Inorganic or organic pigments used in the intermediate layer according to the present invention include kaolin, calcined kaolin, talc, calcium carbonate, synthetic silica, lithopone, barium sulfate, urea-formalin resin fine powder, polystyrene fine powder, etc., with an apparent specific gravity θ , 7.51/cm3 or less, and more preferably, among these pigments, the whiteness is /! A percentage or higher is desirable.

Further, as the film-forming polymer binder used in the intermediate layer according to the present invention, latex such as SBR, MBR, SMBR, emulsion such as acrylic, vinyl acetate, polyester, etc.
Water-soluble polymers such as starch, gelatin, polyvinyl alcohol, polyacrylamide, and styrene-maleic anhydride copolymer salt. Incidentally, a sizing agent or a water-repellent agent such as an alkyl ketene dimer, wax, fatty acid, polyamide polyurea, melamine formaldehyde condensate, etc. may be added to the intermediate layer as necessary.

The coating amount of the intermediate layer according to the present invention is /~/! g/m\preferably 3~/θ,! i'/m2. If the amount applied is less than this, the effect will be small, and if it is more than this, aggregates will tend to form on the coated surface, and it is also unfavorable in terms of cost.

Note that the apparent specific gravity is measured using Becher-Rosenm
uller's method (published by Seibundo Shinkosha, latest pigment handbook/
/Bage). In addition, the measurement of whiteness is T
This was done in conjunction with the appi standard law T standard law approval.

The base papers used in the present invention are NBKP and LBKP.

Although paper is mainly made using wood pulp such as NBSP and LBSP, it is also possible to mix synthetic fibers such as vinylon, polyester, and nylon, or synthetic pulps such as polyethylene and polypropylene. The degree is preferably 200-700cc (C, S, F). In addition, fillers such as clay, Merck, calcium carbonate, and urea-formalin resin fine particles, sizing agents such as σ gin, paraffin wax, higher fatty acid salts, alkyl ketene dimers, and alkenyl succinates, and paper strength agents such as starch and polyacrylamide. If necessary, a fixing agent such as fluorine sulfate, polyamide polyamine epichlorohydrin, etc. may be added.

Further, an anti-curl layer made of latex such as SBR' or MBR, starch, or a water-soluble polymer such as PvA may be provided on the back side of the base paper.

Next, the thermosensitive coloring layer will be explained.

The diazo compound used in the present invention has the general formula A r N
2 + X (wherein, Ar represents an aromatic moiety,
N2+ represents a diazonium group, and X- represents an acid anion. ) It is a compound that can develop a color by causing a coupling reaction with a coupling component, and can be decomposed by light.

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

In the formula, Y represents a substituted amino group, an alkoxy group, an arylthio group, an alkylthio group, or an acylamino group, and R represents an alkyl group, an alkoxy group, an arylamino group, or a halogen (I, Br, CI, F) .

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

Specific examples of diazonium compounds that form salts include terdiazo-/-dimethylaminobenzenteriazo-/
-diethylaminebenzene, terdiazo-/-diethylaminebenzene, terdiazo-/-methylbenzylaminobenzene, terdiazo-/-dibenzylaminobenzene, terdiazo-7-niterhydroxyethylaminobenzene, terdiazo/-diethylamino-3-methoxybenzene, gudiazo -/-dimethylamino-colmethylbenzene, <1-thia7''-/-hensyylamino-, 21!-jethoxybenzene, kudiazo-7-morpholinobenzene, dadiazo/-morpholino-,
! -Jethoxybenzenegudiazo-/-morpholino-
2,J'-dibutoxybenzene, goudiazo-/-anilinobenzene, goudiazo-/-tolylmercapto-
2, t-jethoxybenzene, gudiazo-/, 4t-
Examples include methoxybenzoylamino-2, terjetoxybenzene, diazole/-hydrolidinocoethylbenzene, and the like.

Specific examples of acid anions include CnFzn-)-1cO
0- (n is an integer from 3 to 2), cmF2r11-1-1s
03-(m bar 2~? (D integer), (C, 6F21-
)-xsOz) 20H (l is an integer of Ha/~/r, (n is an integer of 3 to Wa) BF4-1PF6-, and the like.

In particular, as the anion, one containing a -(-fluoroalkyl group or perfluoroalkenyl group), or PF5- is preferable because it causes less increase in capri during raw storage.

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

C4H9 Rishi4n9 The coupling component used in the button of the present invention is one that forms a dye by coupling with a diazo compound (diazonium salt) in a basic atmosphere.Specific examples! : resorcin, phloroglucin 1.2゜3-dihydroxynaphthalene-6-sodium sulfonate, /-hydroxyconaphthoic acid morpholinopropylamide, /, j-
Dihydroxynaphthalene, -93-dihydroxynaphthalene, Co.

3-dihydroxy-ni-sulfanylnaphthalene, -monohydroxy-3-naphthoic acid morpholinopropylamide, -monohydroxy-3-naphthoic acid anilide, co-hydroxy-3-naphthoic acid 1l-J'-methylanilide, co-hydroxy-3-naphthoic acid Ethanolamide, no-hydroxy-3-naphthoic acid octylamide, co-hydroxy-3-naphthoic acid-N-dodecyloxy-glopyramide, λ-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide,
Benzoylacetanilide, /-phenyl-3-methyl-! -Pyrazolone, /- (1.4t/.

, <' -) ') chlorophenyl)-3-benzamide-yo-pyrazolone, '(2' + 4''
+6')dicyclophenyl)-3-anilino-
Yo-Hirazolone, /-Phenyl-3-phenylacetamide-! -Pyrazolone and the like. Furthermore, by using one or more of these coupling components in combination, an image of any color tone can be obtained.

In the present invention, a basic substance is used as necessary, and examples of the basic substance include poorly water-soluble or water-insoluble basic substances and substances that generate dialkali when heated.

Basic substances include inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, virols, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidacillins, and triazoles. Examples include nitrogen-containing compounds such as morpholines, piperidines, amidines, formazines, and pyridines. Specific examples of these are:
For example, ammonium acetate, tricyclohexylamine,
Tribenzylamine, octadecylbenzylamine, stearylamine, allyl urea, thiourea, methylthiourea, allylthiourea, ethylenethiourea, λ-benzylimidazole, gouphenylimidazole, λ-phenyl-g-methyl-imidazole, undecyl-imidazoline , 'J,Q,j-trifuryl-coimidazoline,/.

Kodiphenyluuk, Koudimethyl-koimidasoline, -1-phenyl-2-imitasoline, /.

2,! -) Riphenylguanidine, /, 2-cytoIJ
f7nidine, /, 2-dicyclohexylguanidine, /, 2.3-)dicyclohexylguanidine, guanidine trichloroacetate, N,N'-dibenzylpiperazine, p,4t'-diteomorpholine, Morpholinium trichloroacetate 1.2-amino-benzothiazole, 2-benzoylhydrazino-benzothiazole. These basic substances can be used in combination in amounts of 2'm or more.

The present invention uses a diazo compound encapsulated in a microcapsule, and the diazo compound contained in the core substance of the microcapsule is dissolved or dispersed in a water-insoluble organic solvent, and after emulsification, a microcapsule wall is formed around it by polymerization. However, the organic solvent preferably has a boiling point of /♂0'C or higher. Specifically, phosphoric acid ester,
Phthalate 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, octyl diphenyl phosphate, tricyclohexyl phosphate, diptyl phthalate, dioctyl heptathalate, dilauryl phthalate, dicyclohexyl phthalate, butyl oleate, diethylene glycoludipenzoate, and sebacic acid. Dioctyl, diptyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyl triethyl citrate, octyl maleate, diptyl maleate, isoglobylbiphenyl, inamyl biphenyl, chlorinated paraffin, diisopropylnaphthalene, /, /'-ditolylethane , 2. Gooji tertiary aminophenol, N,N-diptyl-λ-butoxy! -Tertiary octylaniline and the like. Among these, diptyl phthalate,
Particularly preferred are ester solvents such as tricresyl phosphate, dial phthalate, and diptyl maleate.

The microcapsules of the present invention are produced by emulsifying a core material containing a diazo compound and then forming a wall of a polymeric material around the oil droplets. The actant forming the polymeric material 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, styrene methacrylate copolymer, styrene-acrylate copolymer, gelatin, polyvinylpyrrolidone, polyvinyl alcohol, etc. can be mentioned.

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

Preferred polymeric materials include polyurethane, polyurea, polyamide, polyester, and polycarbonate.
GT materials 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 the U.S. Pat.
, 726, 70 da, same j, 7?4. , 4th issue.

For example, when polyurethane is used as a capsule wall material, a polyvalent isocyanate and a first substance (e.g. 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 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.
2tr, special public Shoda♂-gu 0341-7, 4t9-
24t/j No. 9, JP-A No. 4t, r-♂θlri No. 7, No. 4
t/-r4tOt4, and they can also be used.

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

In particular, it is preferable to use a polyvalent incyanate as the first wall-forming substance and a polyol as the first wall-forming substance because of their good shelf life. Furthermore, by combining the two, the thermal permeability of the diazo compound can be changed arbitrarily.

Examples of the polyvalent isocyanate that is the first wall film-forming substance include m-phenylene diiso7anate, p-phenylene diiso7anate, λl≦-tolylene diinocyanate 1.2,4t-)lylene diisocyanate, naphthalene-/, cudiisocyanate, diphenylmethane-x, 4t'-diisocyanate, 3.3'-dimethoxy-4tlg'-biphenyl-diincyanate, j,
J'-dimethyldiphenylmethane, Z'-diisocyanate, xylylene-/, cudiisocyanate, di'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-/, 2-diincyanate, butylene-/ , cordisocyanate, cyclohexylene-/
, cordisocyanate, cyclohexylene-7,4t
- diisocyanates such as diisocyanates), Q, g',
g'-triic anates such as triphenylmethane triisocyanate, toluene-2,4t, (-) diisocyanate, 4t, g'-dimethyldiphenylmethane-2,2', j, tetra'-tetraisocyanate, etc. Incyanate, adduct of hexamethylene diisocyanate and trimethylolpropane, '1g) adduct of lylene diisocyanate and trimethylolpropane, adduct of xylylene diisocyanate and trimethylolpropane, adduct of tolylene diisocyanate and hexanetriol There are isocyanate prepolymers such as

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 a molecular weight of j000 or less and having groups (1), (n), (III), or (IV) shown below between two hydroxyl groups in the molecular structure.

(Aliphatic hydrocarbon group having 2 to 1 carbon atoms) Here, Ar in (■), (■), and (IV) represents a substituted or unsubstituted aromatic moiety, and the aliphatic hydrocarbon group in (I) The hydrogen group has CnH2n- as its basic skeleton, and the hydrogen group may be substituted with another element.

To give a specific example, an example of (I) is ethylene glycol, /,! -7” lopanediol, /, 4-7
'Tandiol,/! -bentanediol, /, 6-
Hexanediol, /, 7-hebutansinol, /, ?
-Octanediol, propylene glycol, 2.3-
dihydroxybutane, /, cordihydroxybutane, /
,3-dihydroxybutane,kodimethyl-/,!
-7"O panediol 1.2.4t-bentanediol, co,!-hexanediol, 3-methyl-/,!-bentanediol, /, 4t-cyclohexane dimetatool, dihydroxycyclohexane, diethylene glycol, /, 2 .6-) Lihydroxyhexane, phenylethylene glycol, /, /, /-trimethylolpropane, hexanetriol, pentaerythritol, glycerin, and the like.

Examples of (n) include condensation products of aromatic polyhydric alcohols and alkylene oxides such as /, 4t-di(2-hydroxyethoxy)benzene, and resorcinol dihydroxyethyl ether.

Examples of (■) include p-xylylene glycol, m-
Xylylene glycol, α, α′-dihydroxy-p-
Diisopropylbenzene etc. are removed.

Examples of (■) are y, 4t/-dihydroxy-
Diphenylmethane, 'CPDP'/Hydroxydiphenylmethyl)benzyl alcohol, Bisphenol A
Examples include adducts of ethylene oxide and adducts of propylene oxide to bisphenol A. The polyol is preferably used in a proportion of hydroxyl groups of 0.02 to 2 moles per mole of incyanate 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.

Both natural and synthetic anionic polymers can be used, such as -〇〇〇, -8Oa
Examples include those having a group or the like. Specific anionic natural polymers include gum arabic and alginic acid, while semi-synthetic products include carboxymethyl cellulose, phthalated gelatin, sulfated starch, sulfated cellulose,
These include licunin 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, Carboxy-modified polyvinyl alcohol, etc.

Examples of non-ionic polymers include polyvinyl alcohol, hydroxyethyl cellulose, and methyl cellulose.

Examples of amphoteric compounds include gelatin.

These water-soluble polymers are used as an aqueous solution of 0007 to 70 wt %. The particle size of microcapsules is 20
Adjusted to less than μ. Generally, if the particle size exceeds 20 μm, the print quality tends to be poor.

In particular, when heating with a thermal head is performed from the coated layer side, the thickness is preferably ♂μ or less in order to avoid pressure blurring.

The diazo compound, which is the main component used in the present invention, the coupling component, and the diazo compound among the basic substances are used as the core material of the microcapsule, but other components may be contained in the core material of the microcapsule. , may be outside the microcapsule.

When the diazo compound and the other seven species are contained in microcapsules, they may be in the same microcapsule or in separate microcapsules.

When two other types are contained in a microcapsule, it is not possible to simultaneously contain three types in the same microcapsule, but there are various combinations.

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

When making microcapsules, the ingredients to be microencapsulated are 0. ．． It can be made from an emulsion containing 2 wt% or more.

The coupling component and basic substance used in the present invention are:
Even if it is contained in the inside of the microcapsule or in the heat-sensitive layer outside the microcapsule, the coupling component is 0.7 to /θ with respect to the diazo compound/part by weight.
Parts by weight, coloring aids are θ.

It is preferable to use it in a ratio of /~20B parts.

Also, the diazo compound is 0. It is preferable to apply the coating at a rate of 0.51/m2.

When the coupling component and the basic substance used in the present invention are not microencapsulated, they are preferably dispersed in a solid form together 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 the water-soluble polymer is 2-jOw L %, and the coupling component and the basic substance are each added to the water-soluble polymer solution in an amount of 3-gQwt%.

The dispersed particle size is preferably 70μ or less.

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

Similarly, metal soaps can also be used to prevent sticking. The amount of these used is 0.
2 to 7 j9/m''.

Furthermore, 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.

As a thermofusible substance, it is solid at room temperature and melts when heated by a thermal head, with a melting point of 10~/! It is a substance at 0°C that dissolves coupling components or basic substances. The thermofusible substance is 0. It is used by dispersing it in the form of particles of /~/θμ and having a solid content of 0.2 to 7 g/m2. Specific examples of heat-melting substances include fatty acid amides, N-substituted fatty acid amides, ketone compounds, R-element compounds, esters, and the like.

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

As a binder, polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, fV7-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 solid content 0. t~jp/m2.

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 as a main component, and other additives, and coating it on a support such as paper or a synthetic resin film with a bar or blade. The solid content is reduced to 2.0% by applying and drying using coating methods such as coating, air knife coating, gravure coating, roll coating, spray coating, and dip coating. ! ~2
A heat-sensitive layer of j 17 / m 2 is provided. Another method is to add the coupling component, the main component of the basic substance, and other additives as the core material of the microcapsules, or to form a coating layer by dispersing them in solid form, or by dissolving them in an aqueous solution and then mixing them. , coated on a support and dried to form a precoat layer with a solid content of 2 to 10 minutes/rn2, and then the main component diazo compound and other additives were added thereon as the core material of the microcapsules. , or apply a coating solution made by dispersing it as a solid or dissolving it as an aqueous solution and mixing it, and dry it to reduce the solid content/~
/! It is also possible to use a laminated type with a coating layer of tg/m2.

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 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.

"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 7 - Comparative Example / - 3 100 parts of LBKP was added to Canadian Freeness 3! θCC
Polyamide polyamine epichlorhythrin 0
．． 2 parts, 0.2 parts of alkyl ketene dimer was added, and the basis weight was 41 J g/m 2 and the thickness was j! A base paper of μ was made. On the above base paper (a) apparent specific gravity 0.7i/
An intermediate layer consisting of a pigment of cm3 or less and (b) a film-forming polymer binder was coated by a bar code method to obtain a support according to the present invention. At this time, examples in which (a) and (b) were variously changed, examples in which no intermediate layer was applied, examples in which (a) was not included, and examples in which (b) was outside the scope of the present invention were used as comparative examples. .

A fixable diazo heat-sensitive coating liquid was applied onto the supports obtained in Examples and Comparative Examples so that the solid content was /θl/m2 to obtain heat-sensitive recording materials.

The contents of these samples are shown in Table 1.

Next, these thermosensitive recording materials were thermally recorded, followed by photofixing, and then the color density was measured. In addition, the yellow density of the background portion was also measured in the same manner. The results are shown in Table 2.

In addition, the manufacturing method of the heat-sensitive coating liquid, the application method, the coloring density,
The method for measuring yellow density is shown below.

(Manufacturing and coating method of heat-sensitive coating liquid) Part of the following diazo compound and (j:/) adduct of xylylene diinocyanate and trimethylolpropane are mixed with tricresyl phosphate, 29 parts and dichloromethane! of the mixed solvent and dissolved therein. A solution of this diazo compound was mixed with 3 parts of polyvinyl alcohol, 7 parts of gelatin,
Gauge (2-hydroxyethoxy)benzene 2-%
Part water t Mix with the aqueous solution dissolved in part a θ0
Emulsified and dispersed with C.

Add 700 parts of water to the resulting emulsion and stir.
C. After one hour, capsules containing the diazo compound and having an average particle size of 3 μm were obtained.

(Diazo compound) Next, add the λθ portion of cohydroxy-3-naphthoic acid anilide! The mixture was added to 100 parts of Tivoli vinyl alcohol aqueous solution and dispersed for about 2 hours using a Su/Domil to obtain a dispersion having an average particle size of 3 μm.

Next, 2Q parts of triphenylguanidine was added to 700 parts of J''% polyvinyl alcohol aqueous solution, and about
Z & time dispersion was performed to obtain a dispersion having an average particle size of 3 μm.

Diazo compound capsule liquid 1 obtained as above
Coupling component dispersion in 0 parts/! 1 part, triphenylguanidine dispersion/j parts were added to prepare a heat-sensitive coating liquid.

(Method of Measuring Color Density and Yellow Density) The obtained heat-sensitive recording material was thermally recorded using a G[[[mode thermal printer (Hifax 700; manufactured by Hitachi, Ltd.), and then Ricopy Super Dry/00 (
The entire surface was exposed to light using Ricoh (manufactured by RICOH ■) 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 2. 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.

"Effects of the Invention" From the results of No. 2 and 2, the heat-sensitive 8-recording material (Examples/--G) according to the present invention has excellent properties in terms of both color development 4 degrees and yellow density. It's obvious that it's a crab.

Patent Applicant Fuji Photo Film Co., Ltd. Procedural Amendment Document Showa to Sasatsu/? Dear Commissioner of the Japan Patent Office, ゛¥Marriage Need'' 1. Indication of the case From the Showa era to the year 2007 patent application No. 17'#A2
No. 2, Title of the invention Thermal recording material 3, Relationship with the case of the person making the amendment Patent applicant 4, Subject of the amendment Column 5 of “Detailed description of the invention” in the specification, “Detailed description of the invention” in the description of the contents of the amendment The description in the "Detailed Explanation" section has been amended as follows.

(1) After "intermediate layer" on page 6/row
”, 3o, preferably 100', IO,1
The range is 00:20. ” Insert all.

Claims (1)

[Claims] In a heat-sensitive recording material in which a heat-sensitive coloring layer consisting of microcapsules encapsulating a diazo compound and a coupling component is provided on a paper support, a (
A heat-sensitive recording material characterized by interposing an intermediate layer consisting of a) an inorganic pigment and/or an organic pigment having an apparent specific gravity of 0.7 g/cm^3 or less and (b) a film-forming polymer binder.