JPH03183588A - Thermally transferable material - Google Patents

Abstract

PURPOSE:To obtain a thermally transferable material which has a satisfactory shelf life and provides high image density with high thermal sensitivity by creating a thermally sensitive layer which contains a coloring component in a microcapsule and a sensitizer component containing alkylphenol on a support. CONSTITUTION:A thermally sensitive layer is provided on a support. Said layer consists of a substantially colorless coloring component A contained in a microcapsule and a sensitizer component B containing an emulsified dispersion product obtained by emulsifying it in an aqueous solution after being dissolved in a solvent which is solution-retardative or insoluble in water with alkylphenol. Alkylphenol is a substance which enhances coloring density during thermal printing or lowers the minimum level of coloring density. The oil obtained by dissolving an emulsified dispersion product such as a coupling component, a basic substance, alkylphenol and a developer in a solvent which is solution- retardative or insoluble in water, and the water containing protective colloid and surfactant are mixed and dispersed using any device used for routine fine particle emulsification such as high-speed stirring or ultrasound dispersion. Thus a thermally sensitive recording material can be obtained easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a heat-sensitive recording material having a transparent heat-sensitive layer, and particularly to a heat-sensitive recording material having a transparent heat-sensitive layer having good storage stability and heat sensitivity.

(Prior art) The thermal recording method has three advantages: (1) no development is required; (2) when the support is paper, the quality of the paper is similar to that of ordinary paper; (3) it is easy to handle; and (4) color density is high. (5) The recording device is simple and inexpensive, and (6) There is no noise during recording, so it has become rapidly popular in the field of black and white factor ξ and printers in recent years. A thermal recording material is a support such as paper or synthetic paper coated with a color forming agent or developer, and is recorded by a heating process using a thermal head based on an electric signal corresponding to the original.

In this field as well, with the rapid development of the information industry, there is an increasing demand for easily obtaining color hard copies from information equipment terminals such as computers and facsimiles.

By the way, when recording color information, it is common to stack layers that produce different hues, and in this case,
In order to make the colored image of the lower layer clear, the upper colored layer must be transparent, but this is a completely new requirement for thermal recording materials that have been aiming to be similar to plain paper. Met.

(Problems to be Solved by the Invention) In response to such demands, the present inventors have developed and already proposed a substantially transparent heat-sensitive recording material (for example, in JP-A-63-9
No. 2489, No. 63-45084). In these heat-sensitive recording materials, some of the coloring components are microencapsulated, so while they have good shelf life and image preservation, it is difficult to increase image density and the heat sensitivity is low. There was a drawback.

As a result of intensive studies from this point of view, the present inventors found that by incorporating an alkylphenol into the heat-sensitive layer, the image density of the transparent heat-sensitive recording material can be increased and the heat sensitivity can be elegantly improved. Reached.

Therefore, a first object of the present invention is to provide a transparent heat-sensitive recording material that can realize high image density.

A second object of the present invention is to provide a transparent heat-sensitive recording material that has good storage stability and high heat sensitivity.

(Means for Solving the Problems) The above aspects of the present invention are such that at least a substantially colorless coloring component A contained in microcapsules is reacted with the coloring component A on a support. In a heat-sensitive recording material provided with a heat-sensitive layer containing a substantially colorless color-forming component B, the heat-sensitive layer includes at least the color-forming component B dissolved together with an alkylphenol in a solvent that is sparingly soluble or insoluble in water. This was achieved by preparing a coating solution containing an emulsified dispersion and the microcapsules emulsified in an aqueous solution, and then applying and drying the coating solution.

The heat-sensitive recording material of the present invention includes an embodiment in which coloring component A is a diazo compound and coloring component B is a coupler, as well as an embodiment in which coloring component A is an electron-donating dye precursor and coloring component B is a color developer. .

In the present invention, the diazo compound used as the color former A reacts with the coupling component described below to develop a desired hue, but it decomposes especially when exposed to light of a specific wavelength before the reaction. However, photodegradable diazo compounds that no longer have color-forming ability even when a coupling component acts on them are preferred. The hue in this coloring system is mainly determined by the diazo dye produced by the reaction between the diazo compound and the coupling component.

The photodegradable diazo compound referred to in the present invention mainly refers to aromatic diazo compounds, and more specifically refers to compounds such as aromatic diazonium salts, diazosulfonate compounds, and cyasia ξ) compounds.

For example, it is said that the photodecomposition wavelength of a diazonium salt is its maximum absorption wavelength. Also, the maximum absorption wavelength of diazonium salts varies from about 200 nm to 700 nm, depending on their chemical structure.
It is known that the change occurs down to about nanometers (“Photodecomposition and chemical structure of photosensitive diazonium salts” by Takahiro Tsunoda and Adai Yamaoka, Journal of the Photographic Society of Japan 29 (4), pp. 197-205 (
1965)).

That is, when a diazonium salt is used as a photodegradable compound, it is decomposed by light of a specific wavelength depending on its chemical structure, and
If the chemical structure of the diazonium salt is changed, the hue of the dye will also change when the coupling reaction occurs, even if the same coupling component is used.

Details of these diazo compounds are described, for example, in JP-A-63-134282.

The color developer for the diazo compound used in the present invention is a coupling component that forms a dye by coupling with the diazo compound (diazonium salt), and specific examples include 2-hydroxy-3-naphthoic acid. In addition to anilide, patent application No. 60-287485 includes resorcinol.
Examples include those listed in the No.

Since the coupling reaction between these diazo compounds and the coupling component is likely to occur in a basic atmosphere, a basic substance may be added to the layer.

As basic substances, water-soluble or water-insoluble basic substances and substances that generate alkalis when heated are used. Examples of these include inorganic and organic ammonium salts, organic amines, amides, urea, and thiosulfides. Urea and its derivatives, deazoles, bi-nols, pyridines, piperazines, guanidines 1, indo-oles, imidazoles, imidapurines, triazoles, morpholines, piperidines, amidines, form Examples include nitrogen-containing compounds such as azines and pinodines.Specific examples thereof are described in, for example, Japanese Patent Application No. 132990/1982.

Two or more basic substances may be used in combination.

On the other hand, the electron-donating dye precursor used in the color-forming unit consisting of a combination of an electron-donating dye precursor and a color developer according to the present invention may be prepared by supplying electrons or by supplying electrons such as acids. It is not particularly limited as long as it has the property of receiving color and developing color, but it is usually approximately colorless,
Compounds that have moieties such as lactone, lactam, sultone, spiropyran, ester, and amide, and whose partial skeletons are ring-opened or cleaved upon contact with a color developer are used. Specifically, there are crystal violet lactone, benzoylleucomethylene blue, malachite green lactone, rhodamine B lactam, 1°2.3-1-dimethyl-6°-ethyl-8°-butoxyindolinobenzos bilobyran, and the like.

Examples of the color developer used with these electron-donating dye precursors include phenol compounds, organic acids or metal salts thereof, and oxybenzoic acid esters. The preferred melting point of the color developer is 50°C to 250″C, especially 60°C.
°C to 200'C, poorly soluble phenols and organic acids in water are preferred.

Specific examples of these color developers are disclosed in Japanese Patent Application No. 601329, for example.
It is described in No. 90.

In the present invention, a microcapsule containing a diazo compound or an electron-donating dye precursor prevents contact between substances inside and outside the capsule due to the substance isolation effect of the microcapsule wall at room temperature, and only when heated above a certain temperature. It is preferable that the material increases the permeability of the substance. The permeation start temperature of the microcapsules can be freely controlled by appropriately selecting the capsule wall material, capsule core material, additives, and the like. The transmission start temperature in this case corresponds to the glass transition temperature of the capsule wall (e.g., Japanese Patent Application Laid-Open No. 59-91438, Japanese Patent Application No. 59-19
No. 0886, Japanese Patent Application No. 59-99490, etc.).

In order to control the glass transition point specific to the capsule wall, it is necessary to change the type of capsule wall forming agent. Capsule wall materials include polyurea, polyurethane, polyurea/urethane mixed capsules, urea-formalin capsules,
Preferred are polyurethane/a/other synthetic resin mixed capsules in which other synthetic resins are encapsulated in the core material, polyester, and polyurea, with polyurethane and polyurea being particularly preferred.

Specific examples of microencapsulation techniques, materials, and compounds used can be found in U.S. Pat. Nos. 3.726804 and 3.
, 796,696.

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

Here, when forming a color-forming unit layer having a combination of a diazo compound and a coupling compound as a color-forming unit, the coupling component is 001 to
It is preferable to use the basic 9F+ material in a proportion of 10 parts by weight and 0.1 to 20 parts by weight, and form a color-forming unit layer in which the color-forming unit is a combination of an electron-donating dye precursor and a color developer. In this case, it is preferable to use 11 parts by weight of a color developer, preferably 0.3 to 80 parts by weight, per 1 part by weight of the electron-donating dye precursor.

Next, the alkylphenol used in the present invention is a substance that increases the coloring density or lowers the minimum coloring temperature during thermal printing, and is a substance that increases the coloring density during thermal printing or lowers the minimum coloring temperature, and is a substance that can be used as a coupling component, a basic substance, a color former, a color developer, or a diazo compound. lowering the melting point,
By lowering the softening point of the capsule wall, it can create a situation where diazo, basic substances, coupling components, electron-donating dye precursors, color developers, etc. can easily react, resulting in thermal sensitivity sensitization. Acts as an agent.

In the present invention, alkylphenols having a total number of carbon atoms other than the phenol skeleton of 2 to 10 are particularly preferred. Examples of such alkylphenols include pt-butylphenol, pt-amylphenol, and pn-amylphenol. , p-5ec-amylphenol, p-
t-octylphenol, p-α-cumylphenol,
3-Methyl-4-isopropylphenol, 2-isopropyl-5-methylphenol, 2-methyl-5-isopropylphenol, P-benzylphenol, 0-benzylphenol, 0-cyclohexylphenol, p
-cyclohexylphenol, p-hexyloxyphenol, p-heptyloxyphenol, p-benzyloxyphenol, 2-t-butyl-4-methoxyphenol, 3゜5-dimethyl-4-chlorophenol, vanillyl alcohol, etc. can be mentioned. Although these can be used alone, it is particularly preferable to use two or more in combination from the viewpoint of solubility.

In any case, it is added to the outside of the microcapsule as an emulsified dispersion together with a coupler or a color developer.

In order to further increase the effect of the alkylphenol mentioned above, a coloring aid may also be used in combination. Such color development aids include phenol compounds other than the alkylphenols mentioned above, alcoholic compounds, amide compounds, sulfonamide compounds, etc. Specific examples include p-tert.
-Octylphenol, p-benzyloxyphenol, phenyl p-oxybenzoate, benzyl carbanylate, phenethyl carbanylate, hydroquinone dihydroxyethyl ether, xylylene diol, N-hydroxyethyl-methanesulfonic acid amide, N-phenyl-methanesulfonic acid Compounds such as amides can be mentioned. These may be contained in the core material or may be added outside the microcapsules as a dispersion.

The heat-sensitive recording material of the present invention contains pigments such as silica, barium sulfate, titanium oxide, aluminum hydroxide, zinc oxide, and calcium carbonate, as well as styrene beads and urea, in order to prevent sticking to a heat head and improve writing properties. −
Fine powder such as melamine resin can be used.

Similarly, metal soaps can also be used to prevent sticking. The usage amount of these is 0.2~
7 g/rrl is appropriate.

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

Binders include polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester, ethylene-vinyl acetate, etc. Various emulsions such as polymers can be used. The amount used is 0.5 to 5 g/nf in terms of solid content.

In the present invention, in addition to the above materials, citric acid, alcohol soap, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid, etc. can be added as acid stabilizers.

The emulsified dispersion of the coupling component, basic substance, alkylphenol, color developer, etc. used in the present invention contains an oil phase in which these are dissolved in a solvent that is sparingly soluble or insoluble in water, a protective colloid, and a surfactant. It can be easily obtained by mixing and dispersing the aqueous phase using means commonly used for fine particle emulsification, such as high-speed stirring and ultrasonic dispersion. By using the emulsified dispersion thus obtained in a coating solution and coating and drying it on a support described below, the transparency of the resulting heat-sensitive layer can be made surprisingly good.

The above support may be a transparent support, depending on the purpose and use.
Both opaque supports such as paper are used.

The paper used for the support is heat extracted pH 6 sized with a neutral sizing agent such as an alkyl ketene dimer.
~9 Neutral paper (described in JP-A-55-14281)
The use of is advantageous in terms of storage stability over time.

In order to prevent the coating liquid from penetrating into the paper and improve the contact between the thermal recording head and the thermal recording layer, Japanese Patent Application Laid-Open No. 57-116687
The paper described in the above-mentioned issue and having a Bekk smoothness of 90 seconds or more is advantageous.

In addition, paper having an optical surface roughness of 8μ or less and a thickness of 40 to 75μ described in JP-A-58-136492, JP-A-58-136492,
Paper with a density of 0°9 g/cm' or less and an optical contact ratio of 15% or more, described in JP-A No. 8-69097, JP-A-58-690
Canadian standard freeness described in No. 97 (JIS P812
Paper made from valves beaten to 4000C or higher in 1) to prevent penetration of coating liquid, JP-A-58-656
No. 95, the glossy side of base paper made by a Yankee machine is used as the coating surface to improve color density and resolution, and JP-A No. 59-35985 describes a method in which the base paper is subjected to corona discharge treatment. Papers with improved coating suitability may also be used in the present invention with good results. In addition to these, any support commonly used in the field of heat-sensitive recording paper can be used as the support of the present invention.

When a transparent support is used as the support, the recorded matter can be used as an OHP sheet or the like.

Transparent supports include polyester films such as polyethylene terephthalate and polybutylene terephthalate;
There are films of cellulose derivatives such as cellulose triacetate films, polystyrene films, polypropylene films, films of polyolefins such as polyethylene, etc., and these can be used alone or in combination.

The thickness of the transparent support used is 20 to 200μ,
Particularly preferred is one of 50 to 100 μm.

The support may be provided with perforations so that the support can be conveyed with high precision during printing.

When a transparent support is used as a support, it can be seen as a transmitted image or a reflected image from one side of the transparent support, but especially in the latter case, if the back side of the background part is visible, the image To make the recorded image look dull, a layer containing a white pigment may be additionally coated on the outermost layer on the reflective side from the viewing side of the recorded image. Examples of preferable white pigments include talc, calcium carbonate, sulfuric acid, etc. Calcium, magnesium carbonate, magnesium hydroxide, alumina, synthetic silica, titanium oxide, barium sulfate, kaolin,
Examples include calcium silicate and urea resin.

In the present invention, an undercoat layer can be provided on the transparent support to enhance adhesion between the transparent support and the heat-sensitive layer.

Gelatin, synthetic polymer latex, nitrile cellulose, etc. are used as the material for the undercoat layer. The coating amount of the undercoat layer is 0.1g/rd to 2.0g/rd. It is preferably in the range of 0g/rd, particularly Q, 2g/rd to 1.0g/rd. Og/rrf
A range of is preferred.

0, 1-g/rr? If it is less, the adhesion between the support and the heat-sensitive layer will not be sufficient; Even if it is increased beyond Og/rrT, the adhesive force between the support and the heat-sensitive layer has reached saturation, which is disadvantageous in terms of cost.

The undercoat layer is desirably cured using a hardening agent, since the image quality of the heat-sensitive layer may deteriorate if it swells with water contained in the heat-sensitive layer when the heat-sensitive layer is coated thereon.

As hardeners that can be used in the present invention, the following can be mentioned.

■Divinylsulfone N,N'-ethylenebis(vinylsulfonylacetamide), 1. ．． 3-bis(vinylsulfonyl)-2-propatur, methylene bismaleimide, 5-acetyl-1,3-diacryloyl-hexahydro=S-)riazine, 1.3.5-triacryloyl-
Active vinyl compounds such as hexahydro-5-) liazine, 1,3.5-)rivinylsulfonyl-hexahydro-5-) liazine.

■2.4-dichloro-6-hydroxy-8,-triazine sodium salt, 2.4-dichloro-6-medoxys-1 riazine, 2.4-dichloro-6-(4-sulfoanilino)-s-triazine・Sodium salt, 2,4-
Dichloro-6-(2-sulfoethylamino)-s-triazine, N-N"-bis(2-chloroethylcarbamyl)
Active halogen compounds such as piperazine.

■Bis(2,3-epoxypropyl)methylpropylammonium p-toluenesulfonate, 1,4-bis(2',3'-epoxypropyloxy)butane, 1
, 3.5-triglycidyl isocyanurate, 1.
Epoxy compounds such as 3-diglycidyl-5-(T-acetoxy-β-oxypropyl)isocyanurate.

■2,4.6-doriethylene-s-triazine, 1.6
Ethyleneimino compounds such as -hexamethylene-N,N'-bisethyleneurea and bis-β-ethyleneiminoethylthioether.

■1.2-di(methanesulfonoxy)ethane, 1.4
-di(methanesulfonoxy)butane, l.

Methanesulfonic acid ester compounds such as 5-di(methanesulfonoxy)pentane.

■Dicyclohexylcarbodiimide, 1-cyclohexyl-3-(3-trimethylaminopropyl)carbodiimide-p-trienesulfonate, 1=ethyl-3-(
3-dimethylaminopropyl) carbodiimide hydrochloride.

■2,5-dimethylisoxazole perchlorate, 2
Isoxazole compounds such as -ethyl-5-phenylisoxazole-3''-sulfonate and 5.5°-(paraphenylene)bisisoxazole.

■Inorganic compounds such as chromium alum and chromium acetate.

■N-carboethoxy 2-isopropoxy 1,2-dihydroquinoline, N-(1-morpholinocarboxy)-
Dehydration bath mold peptide reagents such as 4-methylpyridinium chloride, active ester compounds such as N,N'-aziboyldioxydisuccinimide, N,N''terephthaloyldioxydisuccinimide.

[Phase] Toluene-2,4-diisocyanate, 1゜6-
Isocyanates such as hexamethylene diisocyanate.

■Dialdehydes such as glutaraldehyde, glyoxal, dimethoxyurea, 2,3-dihydroxy-1,4-dioxane, etc. r! 4. Among these, dialdehydes such as glutaraldehyde, 2.degree. 3-dihydroxy-1,4-dioxane, and boric acid are particularly preferred.

The amount of these hardeners added is based on the weight of the base coat material.
3. From 0.20% by weight. An appropriate addition amount can be selected within the range of 0% by weight depending on the coating method and desired degree of curing.

If the amount added is less than 0.20% by weight, the degree of curing will be insufficient no matter how long it is left, and the undercoat layer will swell when the heat-sensitive layer is applied. If the amount is too high, the degree of curing will progress too much, and the adhesion between the undercoat layer and the support will deteriorate, resulting in the disadvantage that the undercoat layer will become film-like and peel off from the support.

Depending on the curing agent used, if necessary, the pH of the solution can be made alkaline by adding caustic soda or the like, or the pH of the solution can be made acidic by adding citric acid or the like.

Moreover, it is also possible to add an antistatic agent if necessary.

Furthermore, before applying the undercoat layer, it is desirable to activate the surface of the support by a known method.

Activation treatment methods include acid etching treatment,
Flame treatment using a gas burner, corona treatment, glow discharge treatment, etc. are used, but from the viewpoint of cost or simplicity, US Pat. No. 2,715.075 and US Pat.
No. 846,727, No. 3.549,406, No. 3
．． Corona discharge treatment, such as that described in No. 590.107, is most preferably used.

In the present invention, an overcoat 1 may be provided on the heat-sensitive layer in order to impart water resistance and scratch resistance.

As the material for the overcoat layer, polyvinyl alcohol, silicon-modified polyvinyl alcohol, gelatin, styrene-maleic anhydride copolymer, starch, etc. may be used alone or in combination as a binder, and further, in order to harden these binders. It is desirable to use the same hardening agent as that used for the above-mentioned undercoat layer, or to use borax, boric acid, colloidal silica, or the like.

In particular, when the main components are silicon-modified polyvinyl alcohol and colloidal silica, an overcoat layer with extremely good transparency can be obtained.

The coating amount of the overcoat layer is from 0.3g/bo to 5g/r.
It is preferably in the range of rf, particularly preferably in the range of 0.5 g/rd to 4 g/rrr.

If the coating amount is less than 0.3g/I, sufficient water resistance and scratch resistance cannot be achieved, and if it is more than 4g/I,
Extra energy is required during printing, which is undesirable.

The coating liquid according to the present invention can be applied by a generally well-known coating method,
For example, dip coating method, air knife coating method, curtain coating method, roller coating method, doctor coating method,
Coating can be performed by a wire barcode method, a slide coating method, a gravure coating method, or an extrusion coating method using Holapara described in US Pat. No. 2,681,294. U.S. Pat. No. 2,761,791 and U.S. Pat. No. 3,508,947, as appropriate.
No. 2,941,898, and No. 3゜526.
Specification No. 528, Yuji Harasaki, "Coating Engineering" 25
It is also possible to divide it into 211 or more parts and apply them at the same time using the method described on page 3 (published by Asakura Shoten, 1973), etc., and an appropriate method can be selected depending on the amount of application, application speed, etc.

Adding pigment dispersants, thickeners, flow modifiers, antifoaming agents, foam inhibitors, mold release agents, colorants, etc. to the coating liquid used in the present invention as necessary will not impair the properties. I have no qualms as far as it goes.

The coating amount of the heat sensitive layer is 3g/rd to 20g/bo, especially 5g/rd.
Preferably it is between nf and 15 g/rrr.

Sufficient sensitivity cannot be obtained below 3g/r;
Even if more than rr is applied, no improvement in quality will be seen, which will be disadvantageous in terms of cost.

In the present invention, the transparent heat-sensitive layer as described above can be easily formed by combining a plurality of heat-sensitive layers, such as stacking them, laminating them on a conventional opaque heat-sensitive layer, or providing heat-sensitive layers on both sides of a transparent support. It can also be made into a multicolor heat-sensitive recording material.

The heat-sensitive recording material of the present invention can be used as a printer sheet for facsimiles and electronic computers that require high-speed recording.

In this case, when a diazo compound is used as a color-forming component, it is especially advantageous for image storage stability to have an exposure zone for photolysis.

Further, as a light source for photolysis, various light sources that emit light of a desired wavelength can be used, and these light sources include, for example, various fluorescent lamps, xenon lamps, xenon flash lamps, mercury lamps of various pressures, photographic flash,
Examples include strobes and the like. Further, in order to make the optical fixing zone compact, the light source section and the exposure section may be separated using an optical fiber.

(Effects of the Invention) The heat-sensitive recording material having a transparent heat-sensitive layer of the present invention uses microcapsules, so it has good raw storage stability and record storage stability. The resulting image density is significantly increased compared to conventional ones, and the thermal sensitivity is extremely good.

(Examples) The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 The following diazo compound: 3.4 parts tricresyl phosphate 2 6 parts methylene chloride 12 parts trimethylolpropane trimethacrylate = 18 parts bamboo) D-11ON (75% by weight ethyl acetate solution) crushed m Shodan T amount - carved r commercial 1 da) ) ・ 9
Part A was combined with 63 parts of an 8% by weight aqueous solution of polyvinyl alcohol (Kuraray PVA-217E) and 10 parts of distilled water.
After adding it to an aqueous solution consisting of 0 parts, it was emulsified and dispersed at 20°C to obtain an emulsion with an average diameter of 2 μm, and the resulting emulsion was continuously stirred at 40″C for 3 hours.

After cooling this liquid to 20''C, Amberlite IR-
120B (manufactured by Rohm and Haas (product name))
00 cc was added, stirred for 1 hour, and then filtered to obtain capsule liquid A.

CHA C1+3 1゜1 part base sensitizer and 10.5 parts of tricresyl phosphate to 1 part of ethyl acetate
0 parts by heating and dissolving.

The obtained oily liquid was mixed with 8% polyvinyl alcohol (1'VA
217E: manufactured by Kuraray ■) and 0.5 g of sodium dodecylbenzenesulfonate in an aqueous solution, and Nippon Seiki ■
Using an Ace homogenizer manufactured by Manufacturer Co., Ltd., at room temperature
Emulsification was performed with OOTPm for 5 minutes to obtain an emulsified dispersion with a particle size of 0.5μ.

Silica-modified polyvinyl alcohol manufactured by Hofushosakugome Dantoku (PVA manufactured by Kuraray ■)
R2105) 10% by weight liquid: 10 parts 1:1 Idarushiri force (Snowtex 30 manufactured by Nissan Chemical) 30% liquid by weight 5 parts Zinc stearate (
Hydrin 2-7) 30 Jukei% liquid manufactured by Middle East Oil and Fat ■
: 0.42 parts paraffin wax (Middle East oil)
Hydrin P-7) 30% by weight liquid: 0
．． 42 parts were mixed to obtain a protective layer liquid A.

After corona discharge treatment was applied to a 75μ thick biaxially stretched polyethylene terephthalate film made by L-Tetsu 2 Futagami Tachisho, capsule liquid A was applied.
A coating solution containing 5.0 parts of the coupler/base dispersion and 7.0 parts of the coupler/base dispersion hole was applied so that the dry coating amount was 68/po.

Next, protective layer liquid A was applied so that the dry coating amount was 2 g/rrf to obtain a recording sheet.

The coating was done using a wire bar and then dried in an oven at 50°C.

Thermal recording was performed on the obtained heat-sensitive recording material using a facsimile machine in GIII mode (Hifax 700) (manufactured by Hitachi, Ltd.), and then Rikobee Super Dry 100 (
■The entire surface was exposed and fixed using a RICOH camera (manufactured by Ricoh). The resulting yellow recorded image density was measured using a Macbeth transmission densitometer.

Next, in order to examine raw storage stability, we measured the skin density (capri) of the heat-sensitive recording material and the capri after storing it in the dark for 24 hours at 90% relative humidity in 40"C2 and performing a forced deterioration test. Measurements were made using a Macbeth transmission densitometer to examine changes in Capri.The results are shown in Table 1.

In addition, to check transparency, haze (%) was measured by Nippon Seiki Kogyo■
The results were also measured using an integrating sphere HTR meter.
Also listed in the table.

Example 2 A heat-sensitive recording sheet was obtained in exactly the same manner as in Example 1, except that 2.degree. C. was used as the sensitizer. Table 1 shows the results of various measurements carried out in exactly the same manner as in Example 1.

Example 3゜60 g of the leuco dye Takenate D-11ON (capsule wall agent manufactured by Takeda Pharmaceutical ■) represented by the following structural formula and 2 g of Sumithorp 200 (ultraviolet absorber manufactured by Sumitomo Chemical ■) were mixed with 55 g of 1-phenyl-1-xylylethane.
and 55 g of methylene chloride were added to a mixed solvent and dissolved. This leuco dye solution was mixed with an aqueous solution of 100 g of 8% polyvinyl alcohol aqueous solution, 40 g of water, and 1.4 g of 2% sodium salt of dioctyl sulfosuccinate (dispersing agent). ．． Emulsify for 5 minutes at OOOrpm, then add 150% water
g was added thereto and reacted at 40''C for 3 hours to prepare a capsule liquid with a capsule size of 0.7 μm.

-〇View Color developer represented by the following structural formula (a) a g, (b) 4
g and (c) 30 g, sensitizer (d) 5 g, (e) 5 and (f) 5 g, l phenyl-1-xylylethane 8.0
g and 30 g of ethyl acetate. The obtained developer solution was mixed with 100 g of an 8% aqueous polyvinyl alcohol solution, 150 g of water, and 0.0 g of sodium dodecylbenzenesulfonate.
It was mixed with 5 g of an aqueous solution and emulsified for 5 minutes at room temperature and 10,000 rpm using an Ace homogenizer manufactured by Nippon Seiki ■ to obtain a particle size of 0. A 5μ emulsified dispersion was obtained.

Color developer (a) zinc salt of Color developer 0')) Color developer (C) Sensitizer (d) )1 C(CLL Hs Sensitizer (e) CH3 Sensitizer (f) CH.

＼ Anger 5 JiJ11 Prepared with Doda 1'35.0 g of the above capsule liquid, 10 emulsified dispersion of color developer
．． 0g, and water 5. Stir and mix Og 7, thickness 75μm
After corona discharge treatment on one side of a transparent polyethylene terephthalate (PET) support, 10g of 1M type
Apply it like this and let it dry to form a heat-sensitive layer.
Next, the same protected p! as used in Example 1 was applied. J liquid A
was applied to the top of the heat-sensitive recording layer so that the solid content was 2.5g10f, and dried in an oven at 50°C.

Recordings were made on the obtained heat-sensitive recording material using the facsimile machine used in Example 1. The obtained black recorded image, fog and transparency before and after the forced deterioration test were measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A heat-sensitive recording sheet was obtained in exactly the same manner as in Example 1, except that no sensitizer was used. The results of various measurements carried out in the same manner as in Example 1 are shown in Table 1.

Comparative Example 2 A heat-sensitive recording sheet was obtained in exactly the same manner as in Example 1, except that 2° was used as the sensitizer. Table 1 shows the results of various measurements carried out in exactly the same manner as in Example 1.

Furthermore, when the coupler/base emulsion was observed under a microscope,
Needle-shaped sensitizer precipitates were observed.

Comparative Example 3 A heat-sensitive recording sheet was obtained in exactly the same manner as in Example 3, except that no sensitizer was used. Table 1 shows the results of various measurements carried out in the same manner as in Example 3.

From the results shown in Table 1, the heat-sensitive recording material according to the present invention can be used in both cases, when a combination of a photodegradable diazo compound and a coupler is employed, and when a combination of an electron-donating dye precursor and a color developer is employed. Also, sensitivity (image density), shelf life (
It was demonstrated that the film improved in terms of fog (fogging) and transparency (haze).

Claims (1)

[Scope of Claims] 1) At least a substantially colorless coloring component A contained in microcapsules and a substantially colorless coloring component B that reacts with the coloring component A to form a color on a support. In the heat-sensitive recording material provided with a heat-sensitive layer containing, the heat-sensitive layer includes at least an emulsion dispersion in which the color-forming component B is dissolved together with an alkylphenol in a solvent that is sparingly soluble or insoluble in water, and then emulsified in an aqueous solution. A heat-sensitive recording material obtained by preparing a coating solution containing the microcapsules and applying and drying the coating solution, and in which the coloring component A is a photodegradable diazo compound or an electron-donating dye precursor. . A heat-sensitive recording material, characterized in that color forming component B is a coupler or a color developer. 2) The heat-sensitive recording material according to claim 1, wherein the color-forming component A is an electron-donating dye precursor and the color-forming component B is a color developer.