JPS6290285A - Thermal recording material - Google Patents

Abstract

PURPOSE:To provide a thermal recording material enhanced in preservability (raw preservability) and excellent in recording image characteristics such as developed color density, by forming a thermal recording layer containing a specific diazo compound. CONSTITUTION:In a thermal recording material wherein a thermal recording layer consisting of a diazo compound and a binder containing and supporting a coupling component is provided on a support, at least a diazo compound represented by general formula [I] (wherein R<1> is a hydrogen or a 1-30 C substituted or unsubstituted alkyl group, R<2> and R<3> are a hydrogen atom, a 1-10 C substituted or unsubstituted alkyl group, an alkenyl group, an aralkyl group or an aryl group, R4 is a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower alkyl ester group or a lower alkylcarbamoyl group and R<4> may be same or different when (m) is 2 or larger. X<-> is an acid anion, (n) is an integer of 1-18 and (m) is an integer of 1-4) is contained in the thermal recording layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a diazo color-forming heat-sensitive recording material using a novel diazo compound.

[Prior Art] As a recording material used in a heat-sensitive recording method, a leuco color-forming heat-sensitive recording material is usually used. In this heat-sensitive recording material, an image is formed on the recording material E by utilizing the fact that one of the leuco dye and the acidic substance dispersed in the heat-sensitive recording layer is melted by natural energy to cause a coloring reaction. It is something.

This is because this recording material has poor fixation of recorded images.

It has the disadvantage that color develops in unexpected places due to harsh handling or heating after recording, 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-57-123086, Journal of the Institute of Image Electronics Engineers, Vol. 290 (1982), etc. describe diazo compounds, coupling components, and 11! This document describes a recording material having a recording layer containing a coloring component consisting of a chemical component (including a substance that becomes basic when heated), and according to this recording material, an image is formed on the recording material E by heating. After that, the recording material is irradiated with light to decompose the unreacted diazo compound and stop color development (fixing).

However, even in recording materials that use diazo compounds,
Precoupling (coloring reaction) progresses gradually during the storage stage before thermal recording, and undesired coloration (capri) tends to occur.

Various improvements have been made to eliminate this coloring (fogging). For example, any of the ingredients that develop color
Either the seeds are present in the form of discontinuous particles (solid dispersion), or the components that develop the color are separated as separate layers.
I (Japanese Unexamined Patent Publication No. 57-123086). This is intended to prevent contact between the components and prevent the progress of pre-coupling. However, in either case, although the shelf life (so-called fresh shelf life) is improved satisfactorily, the thermal response (meltability to heat), which is an important performance, tends to be low.

Furthermore, we developed a non-polar wax-like substance (Japanese Patent Laid-Open No. 57-44
No. 141, JP-A-57-142636, etc.) or a hydrophobic polymer substance (JP-A-57-192,944) to encapsulate one or the other coloring component and isolate it from the other components. It is known.

These encapsulation methods involve dissolving a wax-like substance or a polymeric substance in a suitable solvent, and dissolving or dispersing a coloring component in this solution to form a capsule. This is different from the concept of a normal capsule covered with. For this reason, when a capsule is formed by dissolving a color-forming component, the color-forming component does not necessarily become the core material of the capsule, but mixes uniformly with the encapsulating material, and pre-coupling gradually progresses at the wall interface of the capsule. Furthermore, if the color-forming ingredients are dispersed to form capsules, the color reaction will not occur unless the walls of the capsule are melted by heat, leading to problems such as low heat response. Ta. Furthermore, there is a manufacturing problem in that the solvent used to dissolve the wax-like substance or polymeric substance must be removed after the capsules are formed, and this method is not completely satisfactory.

Therefore, as a method to solve these problems, at least seeds of the components related to the color reaction are contained in a core material, and a wall is formed around this core material using a metal plate to form microcapsules. (Unexamined Japanese Patent Publication No. 59-19088
6, Japanese Unexamined Patent Publication No. 60-6493), etc. have also been proposed.

By the way, the diazo compound conventionally used as a color-forming component requires the use of a large amount of solvent when it is intended to be included as a core material in microcapsules as in Section L. Furthermore, this compound generally did not have sufficient dispersibility in solvents. Therefore, when producing recording materials using these compounds, there are problems in production such as removal of solvents, and the resulting recording materials cannot be expected to have improved recorded image characteristics. . Furthermore, since conventional diazo compounds have not been fully satisfactory in terms of stability to heat or light (meltability to heat, decomposition reactivity to light, etc.), these factors also reduce various properties of heat-sensitive recording materials. This was the cause.

[Summary of the Invention] An object of the present invention is to provide a heat-sensitive recording material that is excellent in recorded image characteristics such as color density.

Another object of the present invention is to provide a heat-sensitive recording material with improved storage stability (raw storage stability).

That is, the present invention provides a heat-sensitive recording material having on a support a heat-sensitive recording layer comprising a diazo compound and a supporting binder containing a coupling component, wherein the heat-sensitive recording layer comprises at least a diazo compound represented by the following general formula (I). The present invention provides a heat-sensitive recording material characterized by a layer containing a compound.

(However, R1 is a hydrogen atom; a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, an alkenyl group, an aralkyl group, an aryl group, an acyl group, an acyloxy group, an ester group, an amide group, a carbamoyl group, a urethane group, A ureido group, a sulfone group, an oxysulfonyl group, a sulfonyloxy group, a sulfonamide group, or a sulfamoyl group. ill2 and R3 are each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, or an alkenyl group. , an aralkyl group, an aryl group, an alkyloxy group, and an aryloxy group, l (4 is a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower alkyl ester group, or a lower alkylcarbamoyl group, and m is When 2 or more, R4 may be the same or different from each other; X- is an acid anion; n is an integer from 1 to 18; -m is from 1 to 4;
As a result of research on diazo color-forming heat-sensitive recording materials, the present inventor found that by using a novel compound represented by the above general formula [I] as a diazo compound as a color-forming component,
The inventors have discovered that a heat-sensitive recording material having excellent properties can be obtained, and have arrived at the present invention.

The novel diazo compound represented by the above general formula [I] of the present invention has extremely good solubility in solvents compared to diazo compounds conventionally used in diazo color-forming heat-sensitive recording materials, and It shows poor solubility in water. Therefore, for example, when it is intended to be included as a core material in microcapsules, the amount of solvent can be minimized and high dispersibility can be obtained. Microcapsules containing a compound in a concentrated state can be formed.

This diazo compound also has excellent properties in terms of stability against heat and light. In other words, it can respond (melt) extremely sensitively in a specific temperature range (for example, the temperature range of heat applied from a thermal head or the like during image recording) in terms of its heat properties, and it can also respond extremely sensitively to light when irradiated. Therefore, this reduces the reactivity with the coupling component in the recording layer! This means that it is possible to significantly increase iA, and at the same time it means that a reliable fixing state can be formed in the developing process (light irradiation after image recording).

From the above, the heat-sensitive recording material using the diazo compound according to the present invention can form a high-density image on the recording layer. Furthermore, since the light fixability can be improved, it becomes possible to significantly reduce coloring (fogging) during storage (during raw storage).

[Structure of the Invention] The heat-sensitive recording material of the present invention has a structure basically consisting of a support and a heat-sensitive recording layer provided thereon.

The heat-sensitive recording layer can be formed on the support, for example, by the method described below.

The heat-sensitive recording layer is a layer containing a diazo compound and a coupling component in a dispersed state with a binder.

The diazo compound, which is a characteristic feature of the present invention, has the following characteristics:
It is a diazonium salt represented by the general formula [I], and is a compound that develops color by causing a coupling reaction with a coupling component.

Todoroki (However, 1li1 is a hydrogen atom, carbon atom number 1 to 30
Substituted or unsubstituted group - (alkyl group, alkenyl group, aralkyl group, aryl group, acyl group.

R2 and 1 (ff
are hydrogen-based f, substituted or unsubstituted with 1 to 10 carbon atoms, J! (alkyl group, alkenyl group, aralkyl group, aryl group, alkyloxy group or aryloxy group), and Ra is a hydrogen atom, a halogen atom,
lower alkyl group, lower alkoxy group, lower alkyl ester group and lower alkyl carbamoyl group, and when m is 2 or more, R4 may be the same or different from each other; X- is an acid anion; n is l m is an integer of 1 to 4) Here, lower means that the number of carbon atoms is 1 to 6.

In the general formula [I], the diazo compound used in the present invention has a total number of carbon atoms of R1, R2 and R3 of 5.
It is preferably in the range of 30 to 30.

In addition, in the above general formula [I], the acid anion representing X is, for example, (a) Cs F2 J-ICO2-(, is 3 to 9
(b) CkF2 is an integer from 2 to 8) (c) (C is an integer from 1 to 18) (c) (C is an integer from 1 to 18) (d) C,, HCON (CH2) 2 Co 2-
C,H.

(1 is an integer from 3 to 9) CH.

(, is an integer from 3 to 9) (i) BF4 - (j) PFs - (k) Z nciL's - and the like. Among these, those containing a perfluoroalkyl group, a perfluoroalkenyl group, or an acid anion of PF6- are particularly preferable because the increase in capri during raw storage is small.

Specific examples of the diazo compound (diazonium 11) according to the present invention include (A) 4-(β-(2,4-di-tert-amylphenoxy)butyloxy)benzenediazonium hexafluorophosphate, [melting point = 145 degrees] (B) 4-(2-phenoxyethyloxy)benzenediazonium hexafluorophosphate, [melting point = 1
28 degrees] (C) 4-octadecyloxybenzenediazonium hexafluorophosphate [melting point: 96 degrees] (D) 4-(2-ethylhexyloxy)benzenediazonium hexafluorophosphate, [melting point 2 8
2 degrees] (E) 4-(tert-octylamidomethyloxy)benzenediazonium hexafluorophosphate, [Melting point: 129 degrees] (F) 4- (N
, N-dibutylamidomethyloxy)benzenediazonium hexafluorophosphate, [
Melting point = 139 degrees] (G) 4- (N, N-di-2-ethylhexylamide methyloxy)benzenediazonium hexafluorophosphate, [melting point = 123 degrees] (
H) 4-(2-ethylhexyloxylcarbonylmethyloxy)benzenediazonium hexafluorophosphate, [melting point: 71 degrees] CI) 4-(benzylamidomethyloxy)benzenediazonium hexafluorophosphate.

[Melting point = 142 degrees] (J) 4-(2,4-di-tert-amylphenoxycarbonylmethyJ-reoxy)benzenediazonium hexafluorophosphate, [Melting point: 110 degrees] (K) 2-(N,N-di Examples include 2-ethylhexylmethyloxy)benzenediazonium hexafluorophosphate [melting point: 97 degrees].

The F diazo compound may be used alone.

Further, depending on the purpose, it may be used in combination with already known diazo compounds.

The coupling component used in the present invention is one that undergoes a coupling reaction with the L diazo compound in a basic atmosphere to develop color, and can be selected depending on the desired hue. Specific examples of these include resorcin, phloroglucin, sodium 2,3-dihydroxynaphthalene 6-sulfonate, sodium 2-hydroxy-3-naphthalene sulfonate, and 2-hydroxy-3-sodium sulfonate.
naphthalenesulfonic acid anilide, 2-hydroquine-3-
Naphthalenesulfonic acid morpholinoamide, 2-hydroxy-3-naphthalenesulfonic acid morpholinopropylamide, 2-hydroxy-3-naphthalenesulfonic acid-2ethylhexyloxypropylamide, 2-hydroxy-
3-naphthalenesulfonic acid-2ethylhexylamide,
1-hydroxy-8-acetylaminonaphthalene-3,
6 Sodium disulfonate, l-hydroxy-8-7
Cetyl aminonaphthalene-3,6-disulfonic acid dianilide, l-hydroxy-2-naphthoic acid morpholinopropylamide, 1.5-dihydroxynaphthalene, 2.3
-dihydroxynaphthalene, 2,3-dihydroxy-6
-Sulfanylnaphthalene, 2-hydroxy-3-naphthoic acid morpholinopropylamide, 2-hydroxy-3
-Naphthoic acid anilide, 2-hydroxy-3-naphthoic acid-2°-methylanilide, 2-hydroxy-3-naphthoic acid ethanolamide, 2-hydroxy-3-naphthoic acid octylamide, 2-hydroxynaphthoic acid morpholinoethylamide , 2-hydroxynaphthoic acid piperidinopropylamide, 2-hydroxynaphthoic acid piperidinoethylamide, 2-hydroxy-3-naphthoic acid-N
-dodecyl-oxy-propylamide, 2-hydroxy-3-naphthoic acid tetradecylamide, acetanilide, acetoacetanilide, benzoylacetanilide,
l-phenyl-3-methyl-5-pyrazolone, 1-(2
',4°,6'-trichlorophenyl)-3-benzamido-5-pyrazolone, 1-(2',4°,6'-trichlorophenyl)-3-7nilino-5-pyrazolone, 1
-phenyl-3-phenylacetamido-5-pyrazolone and the like.

These coupling components may be used alone or
It is also possible to use two inserts together.

The diazo compound represented by formula (I) is contained in the heat-sensitive recording layer in an amount of 0.02 to 2 g/rrf, preferably in a range of o, t-1 g/rrt.

The basic substance for forming the basic atmosphere used in the present invention can be obtained arbitrarily from organic basic substances or substances that generate alkali upon heating. Specific examples thereof include ammonium acetate, tricyclohexylamine, tribenzylamine, octadecylbenzylamine, stearylamine, 2-benzylimidazole, 4-phenylimidazole, 2-phenyl-4-methyl-imidazole.

2-Undecyl-imidacillin, 2,4.5-)rifthal-2-imidacillin, 1,2-diphenyl-4,4-
Dimethyl-2-imidacillin, 2-phenyl-2-imidacillin, 1,2.3-)riphenylguanidine, 1.
2-ditolylguanidine, 1,2-dicyclohexylguanidine, 1゜2,3-tricyclohexylguanidine, guanidine trichloroacetate, N,N'-dibenzylpiperazine, 4.4゛-dithiomorpholine, morpholinium Trichloroacetate, 2-amino-benzothiazole, 2-penzoylhydrazino-benzothiazole and the like can be mentioned. These compounds may be used alone or in combination of -1 or more depending on the purpose.

Examples of binders used in the heat-sensitive recording layer include polyvinyl alcohol boxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone,
Mention may be made of casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester and ethylene-vinyl acetate copolymer, and these compounds are used in the form of various emulsions.

The binder is used at a solids content of 0.5 to 5 g/rr1'.

The heat-sensitive recording layer is prepared by mixing and dispersing the diazo compound, coupling component, basic substance, and binder with an appropriate solvent using a 7-triter, sand mill, etc. to prepare a coating solution. It can be formed by applying a coating solution onto a support by a coating method such as bar coating, blade coating, air knife coating, gravure coating, roll coating, spray coating, or dip coating, and drying.

Further, the recording layer can also be formed by microcapsulating a diazo compound.

The method for forming microcapsules can be carried out using already known methods. I will briefly describe it below.

First, the diazo compound described in L is dissolved or dispersed in a suitable organic solvent, and then this solution or dispersion (oil-based liquid) is emulsified and dispersed in an aqueous medium.

If an organic solvent with a low boiling point is used, there will be evaporation loss during storage, so it is preferable to use one with a boiling point of 180°C or higher. As the organic solvent, phosphoric acid ester, phthalic acid ester, other carboxylic acid ester, fatty acid amide, alkylated biphenyl, alkylated terphenyl, liiJH-halafine, alkylated naphthalene, diarylethane, etc. are used.

Next, a wall made of material is formed around the emulsified and dispersed oil droplets. The adhesive actant to form the polymeric material is added to an oily liquid and/or an aqueous medium.

The polymeric material forming the capsule wall is impermeable and aged at room temperature, but needs to become permeable when heated, and a material with a glass transition temperature of 60 to 200°C is particularly preferred. Examples thereof include polyurethane, polyurea, polyamide, polyester, urea-based formaldehyde resin, melamine resin, polystyrene, styrene/methacrylate copolymer, styrene/acrylate copolymer, and mixtures thereof.

As a method for forming microcapsules, interfacial polymerization method and internal use method are suitable.

For details of the encapsulation force method and specific examples of reactants, see U.S. Pat.
, No. 796,669. For example, when polyurea polyurethane is used as a capsule wall material, a polyisocyanate and a second substance (e.g., polyol, polyamine) that reacts with it to form the capsule wall are mixed into an aqueous medium or an oily liquid to be encapsulated; By emulsifying and dispersing these in water and then heating them, a polymer formation reaction occurs at the oil droplet interface and a microcapsule wall is formed.

Incidentally, an auxiliary solvent with a low boiling point and strong dissolving power may be added to the oily liquid.Even if the addition of the substance described in L is omitted, polyurea will be generated by reacting with water.

Furthermore, when forming microcapsules, a water-soluble component P compound can be used as a protective colloid. Examples of the water-soluble polymer compound include water-soluble anionic polymer compounds, nonionic polymer compounds, and amphoteric polymer compounds.

These water-soluble polymer compounds are contained in an amount of 0.01 to 10% by weight.
It is used as an aqueous solution.

In the case of forming a heat-sensitive recording layer, a substance for increasing the heat-recording density can be further added to the binder solution. Specifically, it has a melting point in the range of 50 to 150°C, preferably in the temperature range of 90 to 130°C, and is selected from compounds that are compatible with diazo compounds, coupling components, or basic substances. Examples include fatty acid amides, ketone compounds, ether compounds, urea compounds, and esters. These compounds are usually dispersed into particles of 1 to 10 .mu.m and used in an amount of 0.2 to 7 g/rr1' of solid content.

In addition, for the purpose of preventing sticking to the thermal head and improving writing properties, pigments such as kaolin, talc, silica, [barium acid, titanium dioxide, aluminum hydroxide, zinc oxide, calcium carbonate, etc.] and styrene beads,
Fine powder of urea, melamine resin, etc. can be added. Similarly, full-strength soaps can also be used to prevent sticking. The amount of these additives added is usually in the range of 0.2 to 7 g/rrf.

In addition to the E additives, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, etc. can also be added as stabilizers.

The recording layer is usually provided with a solid content in the range of 2.5 to 25 g/rn'.

The support used in the present invention can be arbitrarily selected from materials known as supports for heat-sensitive recording materials, such as high-quality paper, synthetic paper, and synthetic resin film, depending on the purpose. For example, as a paper support, heat-extracted neutral paper with a pH of 6 to 9 sized with a neutral sizing agent such as an alkyl ketene dimer (as described in JP-A-55-14281) is preferable in terms of storage stability over time. .Other examples include JP-A-57-
116687, JP 58-136492, JP 5869091, JP 58-656
Papers such as those described in Japanese Patent Application Laid-open No. 95 and Japanese Patent Application Laid-Open No. 59-35985 can be used.

Examples and comparative examples of the present invention will be described in the following margins. However, each of these does not limit the present invention, and in each of the following, "part" means 1 unless otherwise specified.
[Example 1] (i) 30.6 parts of β-2,4-di-tert-amylphenoxybutanol, 16 parts of p-nitrochlorobenzene.
A mixture of 5 parts of anhydrous potassium carbonate, 21 parts of anhydrous potassium carbonate, and 0.5 parts of copper powder was heated at 180°C in an oil bath with 50 parts of dimethylformamide.
After 30 hours of reaction, the product was poured into water, the solid content was filtered off, extracted with ethyl acetate, and washed with water. Ethyl acetate was distilled off to obtain β-(2°,4”-dite
36 parts of rt-amylphenoxy)butyloxy-4-nitrophenyl ether were obtained as an oil.

(ii) 1. The compound 34fi obtained in step (i) was reduced in methanol using hydrazine elongate to give β-(2,
4-tert-amylphenoxy)butyloxy-
4-7 minophenyl ether 3111 was obtained.

(item i) β-(2,4-diter obtained in h) (ii)
31 parts of t-amylphenoxy)butyloxy-4-7minophenyl ether was dissolved in 160 parts of methanol, 18 parts of hydrochloric acid was added, and the mixture was cooled to -5 to 0°C. To this was added an aqueous solution of 5.5 parts of sodium nitrite so that the temperature of the solution did not exceed 0°C to obtain diazonium hydrochloride. To this was added 14.4 parts of potassium hexafluorophosphate, and
After stirring for an hour, the precipitated crystals were collected by filtration, dried, and 4-(β
35.7 parts of -(2,4-di-tart-amylphenoxy)butyloxy)benzenediazonium hexafluorophosphate-) were obtained (yield: 83%).

In this way, diazonium compound (A) was synthesized.

[Example 2] (i) A mixture of 26 parts of 2-ethylhexyl alcohol and 20.2 parts of triethylamine was dissolved in 15 parts of acetonitrile.
0 parts and cooled to 0-5°C. After the reaction, a solution of 45.3 parts of p-nitrophenoxyacetic acid chloride in acetonitrile was added in such a way that the temperature of the solution did not exceed 5°C.The reaction product was poured into a wood, extracted with ethyl acetate, and washed with water.
Ethyl acetate was distilled off to give p-nitrophenoxyacetic acid 2-
56 parts of ethylhexyl ester were obtained.

(ii) L: 41.8 parts of p-7 minophenoxyacetic acid 2-ethylhexyl ester was obtained by performing the same operation as in (11) of Example [I] for 56 parts of the compound obtained in (i). (yield 98%).

(iii) 41.8 parts of the compound obtained in section h (ii) was subjected to the same procedure as in (iii) of Example [I] to obtain 4-(2-ethylhexyloxylcarbonylmethyloxy). 56.9 parts of benzenediazonium hexafluorophosphate was obtained (yield: 87.
%).

In this way, diazonium compound (H) was synthesized.

[¥Stream side 3] (i) In Example 2, β-2,4-G-tert-
The same method as in Example 2 (i) except that a mixture of 46.8 parts of amylphenol and 21.2 parts of triethylamine was dissolved in 200 parts of acetonitrile and 45.2 parts of p-nitrophenoxyacetic acid chloride was used. p-nitrophenoxyacetic acid β-2,4-di-tert-7 milphenyl ester 7
0.51 was obtained (yield 85%).

(ii)): p-7 minophenoxyacetic acid β-2,
40.8 parts of 4-di-tert-amyl phenyl ester were obtained (yield 97%).

(iii) 4-(2,4-di-tert-
40.8 parts of amylphenoxycarbonylmethyloxy)benzenediazonium hexafluorophosphate was obtained (yield*76%).

In this way, diazonium compound (J) was synthesized.

The physical properties (melting point, solubility) of each of the diazonium compounds (A), (H), and (J) thus obtained were evaluated using conventional measurement methods.

The evaluation results are summarized in Table 1.

Table 1 Diazo compounds Melting point 1) TCP (%) Water (A)
145 13 Hardly soluble (H) 7
1 40 Hardly soluble (J) 110
30 Slightly soluble, but tricresyl phosphate (TCP
) refers to the value measured at a liquid temperature of 50°C.

As is clear from the results shown in Table 1, all of the diazo compounds according to the present invention have melting points within the preferred temperature range (60-
150°C), and these compounds are in a solvent (TC
Although it showed high solubility in P), it showed poor solubility in water.

[Example 4] (i) Diazonium compound (A) obtained in Example 1 [
120 parts of 4-(β-(2,4-di-tert-amylphenoxy)butyloxy)benzenediazonium hexafluorophosphate was added to an aqueous polyvinyl alcohol solution (
A diazo compound dispersion having an average particle diameter of 24 m was prepared by adding 100 parts of a 5% by weight solution and dispersing it using a Dyno Mill (manufactured by Bouillier Bacoquin AG).

(ii)) Add 20 parts of Riphenylguanidine to 100 parts of polyvinyl alcohol aqueous solution (5% by weight solution) and disperse using Dynomill (manufactured by Puillier Bacofen AG) to obtain a basic substance dispersion with an average particle I diameter of 3ILm. A liquid was prepared.

(iii) 2-hydroxy-3-naphthoic acid anilide 2
0 parts to 1 part of polyvinyl alcohol aqueous solution (5% by weight solution)
00 parts and dispersed using Dynomil (manufactured by Bouillier Bacofen AG) to prepare a coupling component dispersion having an average particle size of 3 ILm.

(ii) 40 parts of calcium carbonate was added to 60 parts of water in which 0.4 part of sodium hexametaphosphate was dissolved and dispersed using a Dynomill to prepare a calcium carbonate dispersion.

A coating liquid was prepared by mixing 10 parts of the obtained diazo compound dispersion, 10 parts of the basic substance dispersion, 15 parts of the coupling component dispersion, and 15 parts of the calcium carbonate dispersion.

This coating solution was applied to the surface of smooth L-page paper (50 parts/ff1') and dried at a temperature of 40° C. for 30 minutes to form a heat-sensitive recording layer having a dry weight of 5 g/rrf.

In this way, a heat-sensitive recording sheet in which the diazonium compound (A) was dispersed was produced.

[Example 51 - In Example 4, as a diazonium compound (A)
The diazonium compound (H) was prepared by the same procedure as in Example 4 except that (H) [4-(2-ethylhexyloxylcarbonylmethyloxy)benzenediazonium hexafluorophosphate] was used instead of A heat-sensitive recording sheet was produced in which the following were dispersed.

[Example 6] Example 4 except that (J) [4-(2,4-di-tert-amylphenoxycarbonylmethyloxy)benzenediazonium hexafluorophosphate] was used instead of (A) as the diazo compound. Example 4
A heat-sensitive recording sheet in which the diazonium compound (J) was dispersed was produced by carrying out the same operation as in the method described above.

Next, thermal recording was performed using each of the obtained thermal recording sheets.

The heat-sensitive recording sheet was loaded into a facsimile (Melfame 6200 model, manufactured by Mitsubishi Electric Corporation), and the thermal head was operated to record heat on the recording sheet E. A clear red image was obtained with each heat-sensitive recording sheet.

Each heat-sensitive recording sheet on which a recorded image was obtained was evaluated by the coloring density test described below.

Density test From the recording layer side of each heat-sensitive recording sheet, measure the color density (magenta density) on the sheet surface using a Macbeth reflection densitometer (RD-91
8, Macbeth (manufactured by Macbeth)).

The results are shown in Table 2.

Table 2 Example Coloring Density Test 4 0.95 5 1.05 6 1.02 From the results shown in Table 2, it can be seen that thermal recording sheets containing the diazo compound according to the present invention in a dispersed state (Example 4 to 6)
It is clear that a recorded image can be obtained that has a level of image density that is generally required for a heat-sensitive recording material.

In addition, each of the heat-sensitive recording sheets obtained above was evaluated by conducting the raw storage test (humidity resistance, heat resistance, light resistance) described in the following.

Humidity Resistance Test Each heat-sensitive recording sheet was left in an atmosphere with a room temperature of 40° C. and a relative humidity of 90% RH for 24 hours, and the color density on the sheet surface was measured in the same manner as above.

Flycatcher 1 Each heat-sensitive recording sheet was left in an atmosphere with a room temperature of 60° C. and a relative humidity of 30% RH for 24 hours, and the color density on the sheet surface was measured in the same manner as above.

Moisture resistance test The sheet surface side (recording layer side) of each heat-sensitive recording sheet was exposed to a fluorescent lamp (28,000 Jlux)'F for 16 hours, and the color density on the sheet surface was measured in the same manner as described above.

The above results are summarized in Table 3. Table 3 also lists the coloring density before the test.

Table 3 Example Before test Moisture resistance Heat resistance Light resistance 4 0.
08 0.11 0.14 0.125 0
．． 09 0.12 0.14 0.126
0.09 0.12 0.12 0.11 From the results shown in Table 3, it was found that the heat-sensitive recording sheets (Examples 4 to 6) containing the diazo compound according to the present invention in a dispersed state had excellent raw storage properties. It is clear that it has a sexual nature.

[Example 7] (i) Diazonium compound (A) obtained in Example 1 [
15.1 parts of 4-(β-(2,4-di-tert-amylphenoxy)butyloxy)benzenediazonium hexafluorophosphate, 6 parts of tricresyl phosphate
parts, methylene chloride 12 parts, trimethylolpropane trimethacrylate 18 parts and Takenate D-11ON
(manufactured by Takeda Pharmaceutical Co., Ltd.) 24 parts were mixed to prepare a solution serving as a core material.

This solution was added to an aqueous solution in which 63 parts of a polyvinyl alcohol aqueous solution (8% by weight solution) was dissolved in 100 parts of distilled water, and emulsified and dispersed at a temperature of 20°C.
An emulsion of m was obtained. This emulsion was cooled to 20°C while stirring at 40°C for 3 hours to obtain a microcapsule liquid containing the diazo compound (A) as a core material.

(ii) Add 42 parts of triphenylguanidine to 124 parts of a polyvinyl alcohol aqueous solution (6.7% by weight solution) and disperse using Dynomil (manufactured by Bouillier Bacofen AG) to obtain a basic solution with an average particle size of 3 m. A substance dispersion was prepared.

(iii) 2-hydroxy-3-naphthoic acid anilide 2
8 parts of polyvinyl alcohol aqueous solution (4% by weight solution) 1
38 parts and dispersed using a Dyno Mill (manufactured by Vuilli Arbacofen AG) to prepare a coupling component dispersion having an average particle diameter of 3 μm.

10 parts of the obtained microcapsule liquid, 10 parts of the basic substance dispersion, 10 parts of the coupling component dispersion, and 30 parts of calcium carbonate (40ffiH% aqueous solution) were mixed to prepare a coating liquid.

This coating solution was applied to the surface of smooth E-page paper (50 parts/m') and dried at a temperature of 40°C for 30 minutes until the amount of dry balls was 15.
A heat-sensitive recording layer of g/rn' was provided.

In this way, a heat-sensitive recording sheet containing the diazonium compound (A) in microcapsules was produced.

[Example 8] Example 7 except that (H) [4-(2-ethylhexyloxylcarbonylmethyloxy)benzenediazonium hexafluorophosphate] is used instead of (A) as the diazonium compound. A heat-sensitive recording sheet in which the diazonium compound (H) was contained in microcapsules was prepared by carrying out the same operation as in the method described above.

[Example 9] Example 7 except that (J) [4-(2,4-di-tert-amylphenoxycarbonylmethyloxy)benzenediazonium hexafluorophosphate] was used instead of (A) as the diazo compound. Example 7
A heat-sensitive recording sheet in which the diazonium compound (J) was contained in microcapsules was produced by carrying out the same operation as in the method described above.

Next, thermal recording was carried out using each of the heat-sensitive recording sheets obtained in L2 using a device similar to that used in Ibisho, and a clear red image was obtained on each of the heat-sensitive recording sheets.

Subsequently, evaluation was carried out by the same coloring density test as above. The obtained results were almost the same as the measurement results shown in Table E-2. That is, in the thermal recording sheets (Examples 7 to 9) containing microcapsules having a diazo compound as a core material according to the present invention, the thermal recording sheets containing the diazo compound in a dispersed state (Examples 4 to 6) Similar recorded images (colored density) could be obtained.

In addition, each heat-sensitive recording sheet listed in Section L was evaluated by conducting a raw storage test (moisture resistance, heat resistance, and light resistance) under the same conditions as in Section L.

The results are summarized in Table 4. In Table 4, the coloring density before the test is also listed.

Table 4 Example Before test Moisture resistance Heat resistance Light resistance 7 0.
08 0.0? 0.0? 0.0?8
0.0B 0.0B 0.0? 0.0
? 9 0.84 0.0B 0.08 0
．． From the results shown in OEf Table 4, it was found that the heat-sensitive recording sheets (Examples 7 to 9) containing microcapsules having a diazo compound as a core material according to the present invention also have excellent shelf life. is clear.

[Example 10] (i) In (i) of Example 7, the diazo compound (A)
A diazo compound other than the diazo compound according to the present invention was obtained by carrying out the same operation as in the method (+) of Example 7 except that the diazo compound 2,5-dibutoxy-4-morpholinobenzenediazonium hexafluorophosphate was used instead of . A microcapsule liquid containing the diazo compound was prepared.

(11) In (ii) of Example 7, the method is the same as in (ii) of Example 7, except that metaxylylenediamine bispivaloyl acetate amide is used instead of 2-hydroxy-3-naphthoic acid anilide. A coupling component dispersion liquid was prepared by performing the following operations.

In Example 7, Section L (i) and (i) of Example 7
65 parts of the microcapsule liquid obtained in Example 7, 20 parts of the basic substance dispersion, 10 parts each of the coupling component dispersion obtained in (ii) and (11) of Example 7, and 40 parts of the calcium carbonate dispersion. A heat-sensitive recording layer having a dry weight of 20 g/g was provided by mixing the two parts to prepare a coating liquid and performing the same operation as in Example 7 except for using this coating liquid.

In this way, a heat-sensitive recording sheet containing microcapsules each containing a diazonium compound (A) and a diazo compound other than the diazo compound according to the present invention as core materials was produced.

Next, using the thermosensitive recording sheet obtained in L2, thermal recording was performed using the same apparatus as described in E, and a clear black image was obtained on the thermosensitive recording sheet h.

Further, after irradiating this thermosensitive recording sheet with light (wavelength: 400 nm) for 6 minutes, thermal recording was carried out using the same apparatus as described in E, and a red t# river image was obtained on thermosensitive recording sheet F. The density at that time was evaluated by the same coloring density test as in Section E. The obtained results were almost the same as the measurement results shown in Table L Foot Temperature 2 (magenta density: 1.02). In other words, the present invention also applies to a heat-sensitive recording sheet (Example 10) containing microcapsules having a core material of a diazo compound according to 93 years old and microcapsules having a core material of other diazo compounds. It was possible to obtain recorded images (coloring density) similar to those of the heat-sensitive recording sheets containing such diazo compounds in a dispersed state (Examples 4 to 6).

In addition, the heat-sensitive recording sheet described in section h was evaluated by conducting a raw storage test (lit humidity, heat resistance, double light) under the same conditions as above.

The above results are summarized in Table 5. Table 5 also lists the coloring density before the test.

Table 5 Example Before test Moisture resistance Heat resistance Ryohikari 10
0.07 (From the results shown in Table 5 of LO80, 080, 2007, 1. Microcapsules having a core material of the diazo compound according to the present invention and microcapsules having a core material of other diazo compounds) were used in combination. It is clear that the heat-sensitive recording sheet (Example 10) containing the same material also has excellent raw storage stability.

Patent applicant: Tomishichi Photo Film Co., Ltd. Attorney: Yasushi Yanagawa Man procedure -? ##lCorrect: iμ) March 18th, 1986

Claims (1)

[Scope of Claims] A heat-sensitive recording material having on a support a heat-sensitive recording layer comprising a supporting binder containing a diazo compound and a coupling component, wherein the heat-sensitive recording layer has at least the following general formula (
A heat-sensitive recording material characterized by having a layer containing a diazo compound represented by I). General formulas: ▲ Numerical formulas, chemical formulas, tables, etc. R^2 and R^3 are each hydrogen atom or carbon 1
to 10 substituted or unsubstituted alkyl groups, alkenyl groups, aralkyl groups, aryl groups, alkyloxy groups or aryloxy groups; R^4 is a hydrogen atom, a halogen atom, a lower alkyl group, a lower alkoxy group, a lower alkyl group; is an ester group or a lower alkylcarbamoyl group, and when m is 2 or more, R^4 may be the same or different from each other; X^- is an acid anion; n is an integer from 1 to 18; m is an integer from 1 to 4) 2, In the above general formula [I], R^1, R^
2. The heat-sensitive recording material according to claim 1, wherein the total number of carbon atoms of 2 and R^3 is in the range of 5 to 30. 3. The diazo compound represented by the above general formula (I) is
The heat-sensitive recording material according to claim 1, characterized in that the heat-sensitive recording layer contains 0.02 to 2 g/m^2.