JPH0747771A - Thermal recording material for infrared laser - Google Patents

Abstract

PURPOSE:To obtain a material for attaining a recording image in which quinoid dye having a specific structure is used as infrared absorption dye and which has high sensitivity, white skin and high quality in a thermal recording material having a heat sensitive layer containing first colorless color developing ingredient, second colorless color developing ingredient for color developing in reaction with the first ingredient and infrared absorption dye and provided on a support. CONSTITUTION:A thermal recording material comprises a heat sensitive layer containing at least a substantially colorless color developing ingredient A, a substantially colorless color developing ingredient B for color developing in reaction with the ingredient A, and an infrared absorption dye arranged on a support, wherein the absorption dye uses quinoid dye represented by a formula I or II. In the formula II, Z is substituted or non-substituted aliphatic cycle or heterocycle having 5-7 members, and in the formulae I and II, R is H, substituted or non-substituted 1-6C alkyl group or alkoxy group, 5-10C aryl group or hetaryl group, m is integer of 0-4, and n-integer of 0-2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a non-contact heat-sensitive recording material for recording using an infrared laser beam.

[0002]

2. Description of the Related Art A thermal recording method in which a color image is recorded by closely scanning a thermal head on the surface of a thermosensitive recording material having a thermosensitive coloring layer on a support and transmitting heat energy to the thermosensitive recording layer directly or through a protective layer. Is widely known and is applied to facsimiles, printers and the like.

However, in such a thermal recording method, since the thermal head is brought into close contact with the thermal recording material for scanning, the thermal head is worn or the components of the thermal recording material become dust on the surface of the thermal head. Due to the adhesion, there are cases in which a recorded image may not be obtained correctly and the thermal head may be destroyed. Further, the thermal recording method using such a thermal head has limitations in high-speed control of heating / cooling of heating elements and increase in heating element density due to the structural characteristics of the thermal head, so high-speed recording However, there is a limit to high-density and high-quality recording.

In order to solve the above-mentioned drawbacks of the thermal recording system using a thermal head, it has been proposed to perform thermal recording at high speed and high density with a laser beam without contacting the thermal recording material. (For example, JP-A-5
0-23617, 54-121140, 57-
No. 11090, No. 58-56890, No. 58-944
No. 94, No. 58-134791, No. 58-14549.
No. 3, No. 59-89192, No. 60-205182, and No. 62-56195).

However, since the thermosensitive coloring layer generally does not easily absorb light in the visible and near-infrared regions, which are the wavelength regions of laser light that is normally used, in the recording method using the laser beam as described above. However, unless the output of the laser is considerably increased, the heat energy required for color development cannot be obtained, and therefore it is extremely difficult to make a small and inexpensive device. In addition, Japanese Examined Japanese Patent Sho 50-774
Japanese Patent Publication proposes a method in which microcapsules containing ink are applied to base paper, and intense light is emitted to eject the ink in the capsules to record on the base paper, but the sensitivity is very low and still realized. It has not been done.

[0006]

Therefore, many proposals have been made for efficiently absorbing a laser beam in the heat-sensitive recording layer. Generally, in the heat-sensitive recording layer, a light beam matching the wavelength of the laser beam is used. Addition of absorbent material is being done. In this case, if the light-absorbing substance to be added is not white, the background of the recording material is colored, and only low-contrast and poor-quality recording can be obtained.

In general, white light absorbing substances are mostly inorganic compounds, but most of them have low light absorbing efficiency.
It has been desired to develop a compound which is an organic compound having a high light absorption efficiency and is less colored. However, organic compounds that absorb light in the visible region are generally colored,
Also, the darker the color, the higher the light absorption efficiency. Therefore, by adding it as a light absorbing substance to the heat-sensitive recording layer (hereinafter referred to as heat-sensitive layer), the sensitivity can be increased, while the whiteness of the recording paper is good. It will be difficult to do so.

On the other hand, it does not absorb light having a wavelength in the visible light region,
Further, when an organic compound that absorbs a laser beam having a wavelength other than the visible light region is used, the organic compound is not colored, and therefore the background of the recording material is kept white even if it is added to the heat-sensitive layer. It is possible.

When microcapsules are used in the heat-sensitive layer, the light-absorbing substance that absorbs the laser beam is generally inside or outside the microcapsules or inside the walls of the microcapsules (called inside or outside the microcapsules). It absorbs the laser beam that has been added to the imagewise irradiation and converts the energy of the laser beam into heat energy. When the microcapsules are heated by the converted thermal energy, the microcapsule walls become substance-permeable, and the color-forming components inside and outside the microcapsules come into contact with each other to develop color, and an image is recorded on the thermosensitive recording material. It

Therefore, a light-absorbing substance which has a high absorption efficiency of a laser beam but does not absorb light having a wavelength in the visible light region and which has a high efficiency of converting the energy of the absorbed laser beam into heat energy is added to the heat-sensitive layer. By doing so, the sensitivity of thermal recording of the thermal recording material (hereinafter referred to as thermal sensitivity) can be improved, so that not only thermal recording can be performed by a laser having a low output, but also the whiteness of the recording material can be improved. It is possible.

Then, after earnestly studying from the above viewpoint, the inventors of the present invention separated the two color-forming components contained in the heat-sensitive layer by the microcapsules, and also used the quinoid as an infrared absorbing dye inside and outside the microcapsules. The present invention was found by finding that extremely good results can be obtained by incorporating a dye. Therefore, an object of the present invention is to provide a heat-sensitive recording material for infrared laser, which is capable of heat recording with a high-sensitivity, low-power laser, and also enables high-quality recording with less background coloring. .

[0012]

The above objects of the present invention are as follows.
A color-forming component A which is at least substantially colorless on a support;
A heat-sensitive recording material provided with a heat-sensitive layer containing a substantially colorless color-forming component B that develops color by reacting with the color-forming component A and an infrared-absorbing dye, wherein the infrared-absorbing dye is represented by the following chemical formula 3 or 4. It was achieved by a thermal recording material for infrared laser, which is characterized by being a quinoid dye.

[0013]

[Chemical 3]

[Chemical 4]

In the chemical formula 4, Z is a substituted or unsubstituted 5
A 7-membered alicyclic or heterocyclic ring (eg, benzene, trifluorobenzene, phthalic anhydride moiety), wherein R is a hydrogen atom, or a substituted or unsubstituted C 1-6 carbon atom; Alkyl group or alkoxy group, or aryl group or hetaryl group having 5 to 10 carbon atoms (for example, t-butyl group, 2-ethoxyethyl group, n-hexyl group, benzyl group, 3-chlorophenyl group, 2-imidazolyl group). Group, 2-naphthyl group, 4-pyridyl group, methyl group, ethyl group, phenyl group, n-tolyl group, etc.),
m is an integer of 0-4, n is an integer of 0-2.

In the present invention, among the above quinoid dyes used as an infrared absorbing dye, those in which R is a hydrogen atom or a methyl group, and / or Z forms a tetrafluorobenzene ring or a phthalic anhydride moiety. Is preferred. The above quinoid dyes are dyes and pigments [(Dyes & Pigments), Volume 6, 17
It can be easily synthesized by the method described on page 7-88 (1985).

Specific examples of preferable quinoid dyes used in the present invention include compounds represented by the following chemical formulas 5 to 8.

[Chemical 5]

[Chemical 6]

[Chemical 7]

[Chemical 8]

The amount of the quinoid dye used is preferably 0.01 to 10% by weight, more preferably 0.1 to 1% by weight, based on the heat sensitive layer. The color-forming component used in the present invention is a component that causes a color-forming reaction based on contact of a substance, specifically, a combination of a photodegradable diazo compound and a coupler, or an electron-donating dye precursor and an acidic substance. Combinations are preferred.

The photodecomposable diazo compound used in the present invention is a compound that reacts with a developer called a coupling component described below to develop a desired hue, and emits light of a specific wavelength before the reaction. It is a diazo compound that decomposes when received and no longer has the ability to develop color even when the coupling component acts.

The hue in this coloring system is mainly determined by the azo dye formed by the reaction of the diazo compound and the coupling component. Therefore, as is well known, the coloring hue can be easily changed by changing the chemical structure of the diazo compound or the chemical structure of the coupling component, and almost any coloring hue can be obtained depending on the combination. it can.

The photodecomposable diazo compound in the present invention mainly means an aromatic diazo compound, and more specifically, an aromatic diazonium salt, a diazosulfonate compound, a diazoamino compound and the like. The diazonium salt has the general formula A
It is a compound represented by rN ₂ ⁺ X ⁻ (wherein Ar represents a substituted or unsubstituted aromatic moiety, N ₂ ⁺ represents a diazonium group, and X ⁻ represents an acid anion).

It is generally said that the photolysis wavelength of a diazonium salt is its absorption maximum wavelength. The maximum absorption wavelength of the diazonium salt is 200 nm depending on its chemical structure.
It is known to change from the position to 700 nm (“Photolysis and chemical structure of photosensitive diazonium salts” by Takahiro Tsunoda and Ao Yamaoka, Journal of the Photographic Society of Japan 29 (4) 197-1.
05 (1965)).

That is, when a diazonium salt is used as a photodecomposable compound, it is decomposed by light having a specific wavelength according to its chemical structure, and if the chemical structure of the diazonium salt is changed, the same coupling component and coupling reaction can be obtained. The hue of the dye when changed is also changed. Many diazosulfonate compounds that can be used in the present invention are known, and they can be obtained by treating each diazonium salt with a sulfite.

The diazoamino compound which can be used in the present invention has a diazo group coupled with dicyandiamide, sarcosine, methyltaurine, N-ethylanthranic acid-5-sulphonic acid, monoethanolamine, diethanolamine, guanidine and the like. The compound. For more information on these diazo compounds,
For example, it is described in JP-A-2-136286.

As a light source for photolysis of diazo compounds,
Various light sources which emit light of a desired wavelength can be used, for example, various light sources such as various fluorescent lamps, xenon lamps, xenon flash lamps, mercury lamps of various pressures, photographic flashes and strobes. or,
In order to make the light fixing zone compact, the light source unit and the exposure unit may be separated by using an optical fiber.

The coupling component used in the present invention for forming a dye by coupling with a diazo compound includes, for example, 2-hydroxy-3-naphthoic acid anilide and resorcin as a starting point, and JP-A-62-146678. The thing described in the gazette can be mentioned. Further, an image having an arbitrary color tone can be obtained by using two or more of these coupling components in combination. Therefore, the present invention is not limited to a monochromatic heat-sensitive recording material.

Since the coupling reaction between these diazo compounds and the coupling component easily occurs in a basic atmosphere, a basic substance may be added in the heat sensitive layer. As the basic substance, a poorly water-soluble or water-insoluble basic substance or a substance which generates an alkali upon heating is used.

Examples thereof are inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles and imidazolines. And nitrogen-containing compounds such as triazoles, morpholines, piperidines, amidines, formazines and pyridines. Specific examples of these are described, for example, in JP-A-61-291183. Two or more basic substances may be used in combination.

The electron-donating dye precursor used in the present invention is not particularly limited, but it has a property of developing a color by donating electrons or accepting a proton such as an acid, A compound which is substantially colorless and has partial skeletons such as lactone, lactam, sultone, spiropyran, ester, amide, etc., and these partial skeletons are ring-opened or cleaved upon contact with a color developer is used.

Specifically, crystal violet lactone, benzoyl leuco methylene blue, malachite green lactone, rhodamine B lactam, 1,3,3-
Trimethyl-6'-ethyl-8'-butoxyindolinobenzospiropyran and the like. As a developer for these color formers, an acidic substance such as a phenol compound, an organic acid or a metal salt thereof, and oxybenzoic acid ester is used, and specific examples thereof are, for example, JP-A-61-291183.
It is described in Japanese Patent Publication No.

The color-forming component used in the present invention is to improve the transparency of the heat-sensitive layer, from the viewpoint of raw storability to prevent contact of the color-forming component at room temperature (prevention of fog), and to develop color with desired laser energy. From the viewpoint of controlling the color development sensitivity, the color forming components of A and B are used by being encapsulated in different microcapsules, or one of A and B is microcapsulated and used.

Any of an interfacial polymerization method, an internal polymerization method and an external polymerization method can be adopted for producing the microcapsules used in the present invention. In particular, a core substance containing a color forming component is water-soluble. It is preferable to employ a method of emulsifying the polymer in an aqueous solution in which the polymer is dissolved and then forming a wall of the polymer substance around the oil droplets. The reactant forming the polymer substance is added inside the oil droplet and / or outside the oil droplet.

Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer,
Examples thereof include styrene-acrylate copolymer. Preferred polymeric substances are polyurethanes, polyureas, polyamides, polyesters and polycarbonates, particularly preferably polyurethanes and polyureas. Two or more polymer substances can be used in combination. Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like.

For example, when polyurea is used as a capsule wall material, polyisocyanates such as diisocyanate, triisocyanate, tetraisocyanate and polyisocyanate prepolymer, and polyamines such as diamine, triamine and tetraamine, and amino groups. A microcapsule wall can be easily formed by reacting a prepolymer containing two or more of the above, piperazine or a derivative thereof, a polyol, and the like with an interfacial polymerization method in an aqueous solvent.

Further, for example, the composite wall composed of polyurea and polyamide or the composite wall composed of polyurethane and polyamide is added, for example, by using polyisocyanate and acid chloride or polyamine and polyol, after adjusting the pH of the emulsifying medium as the reaction liquid. It can be prepared by warming. For details of the method for producing a composite wall composed of these polyurea and polyamide, see JP-A-58-6.
6948.

The core substance of the microcapsules used in the present invention may contain the above-mentioned quinoid dye as an infrared absorbing pigment, but of course, it may be contained outside the microcapsules or in the walls of the microcapsules.
It may be contained in two or more places at the same time.

When added to the outside of the microcapsules, from the viewpoint of preventing coloration of the heat-sensitive recording material, it is preferable to appropriately select and use a quinoid dye having a group having low light absorption in the visible light region. When added to the microcapsule wall, it is preferable to use a quinoid dye having an active group that reacts with the microcapsule wall material during formation of the microcapsule, from the viewpoint of preventing the dye from coming out of the microcapsule. .

Specific examples of the above-mentioned active group include an isocyanate group, a hydroxy group, a mercapto group and an amino group, but an isocyanate group and a hydroxy group are particularly preferable. Further, the thermal sensitivity can be increased by adding a solid sensitizer to swell the microcapsule wall when heating the laser beam.

The solid sensitizer may be selected from those which are said to be plasticizers for polymers used as microcapsule walls and have a melting point of 50 ° C. or higher, preferably 120 ° C. or lower, and are solid at room temperature. it can. For example, when the wall material is made of polyurea or polyurethane, a hydroxy compound, a carbamic acid ester compound, an aromatic alkoxy compound, an organic sulfonamide compound, an aliphatic amide compound, an arylamide compound and the like are preferably used.

In the present invention, it is also possible to use a coloring aid. The coloring aid that can be used in the present invention is a substance that increases the coloring density at the time of laser heating recording or lowers the minimum coloring temperature, lowers the melting point of the coloring component or the basic substance, or capsules. This is to create a situation in which the color-forming component A and the color-forming component B are likely to react with each other by the action of lowering the softening point of the wall.

Examples of the coloring aid include phenol compounds, alcoholic compounds, amide compounds, sulfonamide compounds and the like. Specific examples are p-tert-octylphenol, p-benzyloxyphenol, phenyl p-oxybenzoate, Examples thereof include benzyl carbanylate, phenethyl carbanylate, hydroquinone dihydroxyethyl ether, xylylenediol, N-hydroxyethyl-methanesulfonic acid amide, N-phenyl-methanesulfonic acid amide. These may be contained in the core substance or may be added outside the microcapsules as an emulsified dispersion.

In the present invention, when only one of the color forming components is microencapsulated, it is preferable to microencapsulate the diazo compound or the electron donating dye precursor. In this case, the coupler or the color developer or the quinoid dye can be used by dispersing them in a solid state.
After dissolving in a water-insoluble or insoluble organic solvent together with the coupler or developer, this was mixed with an aqueous phase containing a surfactant and having a water-soluble polymer as a protective colloid, and emulsified and dispersed. It can also be used in the form of a dispersion. In the latter case, the heat sensitive layer can be transparent.

The organic solvent used when preparing the above emulsified dispersion can be appropriately selected from high boiling point oils. Among them, preferable oils include, in addition to esters, dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene, dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, diisobutylbiphenyl, 1-methyl-1-dimethylphenyl-1-phenylmethane, 1-ethyl- 1-dimethylphenyl-1
-Phenylmethane, 1-propyl-1-dimethylphenyl-1-phenylmethane, triallylmethane (for example,
And triphenylyl methane, toluyl diphenyl methane), terphenyl compounds, alkyl compounds, alkylated diphenyl ethers (eg propyl diphenyl ether), hydrogenated terphenyls (eg hexahydroterphenyl), diphenyl ethers and the like. Among these, it is particularly preferable to use esters from the viewpoint of emulsion stability of the emulsion dispersion.

Examples of the esters include phosphoric acid esters (eg, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, cresyl diphenyl phosphate), phthalic acid esters (dibutyl phthalate, 2-ethylhexyl phthalate, phthalic acid). Ethyl, octyl phthalate, butylbenzyl phthalate), tetrahydrophthalate dioctyl, benzoic acid ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate), abietic acid ester (ethyl abietic acid, Benzyl abietic acid), dioctyl adipate, isodecyl succinate, dioctyl azelate, oxalate ester (dibutyl oxalate, dipentyl oxalate), diethyl malonate, maleate ester (dimethyl maleate, maleic acid) Diethyl acid, dibutyl maleate), tributyl citrate, sorbate (methyl sorbate, ethyl sorbate, butyl sorbate), sebacate (dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (formic acid monoester) And diesters, butyric acid monoesters and diesters, lauric acid monoesters and diesters, palmitic acid monoesters and diesters, stearic acid monoesters and diesters, oleic acid monoesters and diesters), triacetin, diethyl carbonate, diphenyl carbonate, ethylene carbonate, carbonic acid propylene,
Examples thereof include boric acid esters (tributyl borate, tripentyl borate) and the like.

Among these, the use of tricresyl phosphate alone or in combination is preferable because the emulsion dispersion stability of the developer is particularly good. It is also possible to use the above oils in combination, or to use in combination with other oils. In the present invention, an auxiliary solvent may be added to the above organic solvent as a low boiling point dissolution aid. As such an auxiliary solvent, for example, ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like can be mentioned as particularly preferable ones.

The water-soluble polymer to be contained as a protective colloid in the aqueous phase mixed with the oil phase containing these components is appropriately selected from known anionic polymers, nonionic polymers and amphoteric polymers. However, polyvinyl alcohol, gelatin, cellulose derivatives and the like are preferable.

As the surface active agent to be contained in the aqueous phase, an anionic or nonionic surface active agent which does not cause precipitation or aggregation by acting on the protective colloid may be appropriately selected and used. it can. Preferred surfactants include sodium alkylbenzene sulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (eg, polyoxyethylene nonylphenyl ether), and the like.

For the emulsified dispersion of the present invention, an oil phase containing the above components and an aqueous phase containing a protective colloid and a surfactant are used by means such as high-speed stirring and ultrasonic dispersion, which are used for ordinary fine particle emulsification. Then, they can be mixed and dispersed, and easily obtained. The ratio of the oil phase to the water phase (oil phase weight / water phase weight) is preferably 0.02 to 0.6,
It is particularly preferably 0.1 to 0.4. When it is 0.02 or less, the amount of the water phase is too large to be diluted, and sufficient color developability cannot be obtained. On the other hand, when it is 0.6 or more, the viscosity of the liquid is increased, which causes inconvenience in handling and a decrease in coating liquid stability.

If necessary, pigments, waxes, hardeners, etc. may be added to the heat-sensitive layer. When applying the heat-sensitive layer liquid prepared as described above on the support, blade coating method, air knife coating method, gravure coating method, roll coating coating method, spray coating method, dip coating method, bar coating method, etc. A known coating means using a water-based or organic solvent-based coating liquid is used.

In this case, in order to apply the heat-sensitive layer liquid safely and uniformly and to maintain the strength of the coating film, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, polyvinyl alcohol are used as the binder in the present invention. , Carboxy-modified polyvinyl alcohol, polyacrylamide, polystyrene and its copolymers, polyester and its copolymers, polyethylene and its copolymers, epoxy resins, acrylate and methacrylate resins and their copolymers, polyurethane resins and polyamide resins Etc. can also be used in combination for coating.

It is desirable that the heat-sensitive layer is coated so that the total amount of the color-forming component and the quinoid dye is 1 to 20 g / m ² , and that the thickness of the layer is 1 to 20 μm. The support used in the present invention may be transparent or opaque. As the transparent support, it is preferable to use a support which does not absorb the irradiation laser beam and has dimensional stability that does not deform with respect to heat generated during laser irradiation. In this case, a laser beam may be irradiated through the transparent support for recording. The thickness of the support is 10 μm to 200 μm.

As such a transparent support, for example,
Polyester film such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative film such as cellulose triacetate film, polystyrene film, polypropylene film, polyolefin film such as polyethylene film, polyimide film, polyvinyl chloride film, polyvinylidene chloride film,
Examples thereof include polyacrylic films and polycarbonate films, which can be used alone or in combination.

On the other hand, examples of the opaque support for the recording material include paper, synthetic paper, an aluminum vapor deposition base, and the above transparent support coated with a pigment or the like. In this case,
In order to irradiate the laser beam from the heat-sensitive layer side and efficiently absorb it in the heat-sensitive layer, it is preferable to use an opaque support of the recording material having a high laser beam reflectivity.

When a polymer film is used as the support, an undercoat is applied on the support before the application of the heat-sensitive layer liquid containing microcapsules in order to prevent the whole heat-sensitive layer from peeling off from the support. It is desirable to provide layers. As the undercoat layer, an acrylic ester copolymer,
Polyvinylidene chloride, SBR, aqueous polyester and the like can be used, and the film thickness is preferably 0.1 to 0.5 μm.

The undercoat layer composed of these compositions is applied by the same application method as that for applying the heat-sensitive layer liquid.
The coating amount is preferably 0.1 to 10 g / m ² ,
In particular, it is preferably 0.2 to ² g / m ² . The laser beam used in the present invention has a wavelength in the infrared region. Specific examples thereof include a helium-neon laser, an argon laser, a carbon dioxide gas laser, a YAG laser, and a semiconductor laser.

The heat-sensitive layer of the recording material of the present invention contains a quinoid dye as an infrared absorbing pigment at least at one location inside, outside and inside the wall of the microcapsule.
The infrared absorbing dye absorbs the irradiated laser beam and converts its energy into heat energy. As a result, the microcapsules are heated to become substance permeable and the pressure inside the microcapsules increases, and as a result, the reactive substances inside and outside the microcapsules pass through the microcapsule walls and come into contact with each other to develop color.

[0056]

INDUSTRIAL APPLICABILITY The heat-sensitive recording material for infrared laser of the present invention has high absorption efficiency of infrared laser and high efficiency of converting laser beam energy into heat energy even though it has little absorption of visible light. As an absorption dye,
Since the quinoid dye is contained in the heat-sensitive layer, it is excellent in heat sensitivity, can be heat-recorded by a small-sized and low-power infrared laser, and can record with good quality with little background coloring.

[0057]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.
In addition, "part" indicating the addition amount indicates "part by weight".

Example 1. Preparation of dispersion 2-anilino-3-methyl-6-N-dibutyl-aminofluorane (color former) 20 g, bisphenol A (developer) 20 g and β-naphthyl-benzyl ether (sensitizer) 20 g and the following: 20 g of the quinoid dye (infrared absorbing dye) represented by Chemical formula 9 is independently added to 100 g of a 5 wt% polyvinyl alcohol (PVA-105: trade name of Kuraray Co., Ltd.) aqueous solution, and a ball mill is used overnight. Dispersion was performed to obtain respective dispersions of a color former, a developer and a sensitizer having an average particle diameter of 1.5 μm or less.

[Chemical 9] On the other hand, 80 g of calcium carbonate was added to 160 g of a 0.5 wt% aqueous solution of sodium hexametaphosphate and dispersed using a homogenizer to obtain a pigment dispersion liquid.

Preparation of Thermosensitive Recording Material 5 g of the color developer dispersion, 10 g of the developer dispersion, 10 g of the sensitizer dispersion, 5 g of the pigment dispersion and 1 g of the infrared absorbing dye dispersion obtained above were stirred and mixed to obtain a base paper. amount to fine paper of 50 g / m ^2, the coating amount after drying was coated using a wire bar such that the 6 g / m ^2, then dried with 50 ° C. oven to obtain a heat-sensitive recording material .

From the heat-sensitive layer side of the heat-sensitive recording material produced as described above, the output is 40 on the surface of the heat-sensitive layer in 1 millisecond.
Laser beam with a wavelength of 830 nm (GaAs junction laser) whose energy was adjusted to mJ / mm ^2.
Was imagewise irradiated to obtain a black recorded image. The reflection density of the color-developed portion of the obtained image was measured using a Macbeth densitometer and found to be 1.23, and almost no coloring of the background of the recording material was observed.

Example 2. Preparation of capsule liquid Crystal violet lactone (leuco dye) 14
g, 75% by weight ethyl acetate solution of xylylene diisocyanate and trimethylolpropane (3: 1) adduct (Takenate D-110N: trade name of capsule wall material manufactured by Takeda Pharmaceutical Co., Ltd.) 60 g, and ultraviolet absorber (Sumisorb) 200: Trade name of Sumitomo Chemical Co., Ltd.) 2 g, 1-
It was added and dissolved in a mixed solvent of 55 g of phenyl-1-xylylethane and 55 g of methylene chloride.

100 g of an aqueous solution of polyvinyl alcohol of 8% by weight, 40 g of water and 1.4 g of a sodium salt of dioctyl sulfosuccinate (dispersing agent) of 2% by weight were prepared.
After being mixed with the aqueous solution of 1., emulsification was performed for 5 minutes at 10,000 rpm using an ace homogenizer (manufactured by Nippon Seiki Co., Ltd.). After further adding 150 g of water to the obtained emulsion, an encapsulation reaction was carried out at 40 ° C. for 3 hours to prepare a capsule solution having an average particle size of 0.7 μm.

Preparation of color developer emulsified dispersion 8 g of the developer represented by the following formula 10, 4 g of the developer represented by the following formula 11, 30 g of the developer represented by the following formula 12, and the following formula 4 g of the infrared absorbing dye represented by 13 was added to 8.0 g of 1-phenyl-1-xylylethane and 30 g of ethyl acetate.
g of the mixed solution. The resulting solution was mixed with 100 g of an aqueous 8% by weight polyvinyl alcohol solution, 150 g of water, and an aqueous solution of 0.5 g of sodium dodecylbenzenesulfonate, and then 10,000 rpm using an ace homogenizer (manufactured by Nippon Seiki Co., Ltd.). Emulsification was performed for 5 minutes so that the average particle size was 0.5 μm at room temperature to obtain an emulsified dispersion.

[0064]

[Chemical 10]

[Chemical 11]

[Chemical 12]

[Chemical 13]

Preparation of heat-sensitive recording material 5.0 g of the above capsule liquid, the above-mentioned developer emulsion dispersion 10.
A liquid obtained by stirring and mixing 0 g and 5.0 g of water with a thickness of 70 μm
m transparent polyethylene terephthalate (PET) support was coated to a solid content of 15 g / m ² and dried. On the heat-sensitive layer formed as described above, the protective layer liquid having the composition shown in Table 1 below was dried to a thickness of 2
The transparent heat-sensitive recording material according to the present invention was produced by coating and drying so as to have a thickness of μm.

[0066]

[Table 1] ─────────────────────────────────── Composition of the protective layer liquid 10% by weight Polyvinyl alcohol 20 g Water 30 g 2% by weight Sodium salt of sulfosuccindiooctyl 0.3 g Polyvinyl alcohol 3 g, kaolin dispersion obtained by dispersing 100 g of water and 35 g of kaolin in a ball mill 3 g Hydrin Z-7 (trade name of Chukyo Yushi Co., Ltd.) 0.5 g ─ ───────────────────────────────────

From the heat-sensitive layer side of the heat-sensitive recording material produced as described above, a semiconductor laser beam (GaAs junction laser) having a wavelength of 830 nm was imagewise irradiated to obtain a blue recorded image. The laser output is 1 on the surface of the heat sensitive layer.
The energy was adjusted to 40 mJ / mm ^{2 in} milliseconds. The transmission density of the colored portion of the obtained image was measured using a Macbeth densitometer and found to be 2.12.
The density of the background part was 0.15.

Example 3. Instead of the crystal violet lactone used in Example 2 and the infrared absorbing dye represented by Chemical formula 13, 2-anilino-3-methyl-6-
N-ethyl-N-butylaminofluorane and the following chemical formula 1
A heat-sensitive recording material was prepared in the same manner as in Example 2 except that the quinoid dye represented by 4 was used, and an image was recorded to obtain a transparent black image.

[Chemical 14] The transmission density of the colored portion of the obtained image was measured by using a Macbeth densitometer and was 2.06. The density of the background portion was 0.17.

Example 4. Preparation of Capsule Liquid 50 parts of compound represented by the following Chemical formula 15, methylene chloride 150 g, tricresyl phosphate 50 parts, trimethylolpropane trimethacrylate 150 parts and m
-A 75 wt% ethyl acetate solution of trimethylolpropane 3: 1 adduct of xylylene diisocyanate (Takenate D110N: trade name of capsule wall material manufactured by Takeda Pharmaceutical Co., Ltd.) 200 parts is uniformly mixed to obtain an oil phase solution. And

[Chemical 15]

On the other hand, 7% by weight of polyvinyl alcohol (PVA217E: saponification degree 88 to 89%, polymerization degree 1,
700: 600 parts of Kuraray Co., Ltd.) was prepared to obtain a water-soluble polymer aqueous solution. Then 5 with hot bath
The dissolver was attached to a liter stainless steel pot, the aqueous polymer solution was added, the oil phase solution was added while stirring the dissolver, and the average particle size of the emulsion was about 1.5 μm while observing with a microscope. And emulsified and dispersed so that

After completion of the emulsification and dispersion, the stirring was loosened and the mixture was placed in a warm bath.
The encapsulation reaction was completed in 3 hours while keeping the temperature in the pot at 40 ° C. by passing warm water of ℃. 25 ml of an ion exchange resin (MB-3: trade name of Organo Co., Ltd.) was added to the obtained liquid, stirred, and then filtered to obtain a capsule liquid.

Preparation of Dispersion A The substances shown in Table 2 below were mixed and dispersed in a dissolver in advance, and then Dynomill (Willie A. Bacofen.
Dispersion liquid A was obtained by dispersing with A.G. (manufactured by WILLY A. BACHOFEN AG) so that the average particle size was 2 μm.

[0073]

[Table 2] ─────────────────────────────────── 15 wt% polyvinyl alcohol aqueous solution 30 parts (PVA- 205 Trade name of Kuraray Co., Ltd.) Coupler of Chemical 16 4.3 parts

[Chemical 16] 0.6 part of coupler of chemical formula 17

[Chemical 17] 5.0 parts of the organic basic compound of Chemical formula 18

[Chemical 18] Chemical Development Agent of Chemical Formula 3.0 3.0 parts

[Chemical 19] Quinoid dye of Chemical formula 20 (infrared absorbing pigment) 0.5 part

[Chemical 20] ───────────────────────────────────

Preparation of Dispersion B The substances shown in Table 3 below were mixed and stirred to obtain Dispersion B.

[Table 3] ─────────────────────────────────── Univer 70 (trade name of Shiraishi Industry Co., Ltd. ) 20 parts Caobright (trade name of Thiele Kaolin Company) 40 wt% sodium hexametaphosphate aqueous solution 0.5 parts water 30 parts ───────────────── ────────────────────

Preparation of thermosensitive recording material 20 parts by weight of the above-mentioned capsule liquid, 20 parts by weight of dispersion liquid A, 7 parts by weight of dispersion liquid B and a surfactant (Nissan Rapizol 13-90: trade name of NOF Corporation) 2% by weight aqueous solution 1. Five parts were stirred and mixed, and coated on a polyethylene terephthalate (PET) support having a thickness of 70 μm so that the solid content was 15 g / m ^2, and dried to form a heat-sensitive layer. Further, a mixture having a composition shown in Table 4 below was applied on the heat-sensitive layer so that the thickness after drying was 2 μm to form a protective layer, and the heat-sensitive recording material of the present invention (hereinafter referred to as recording material) Was produced.

[0076]

[Table 4] Composition of protective layer ─────────────────────────────────── 10% by weight polyvinyl alcohol 20 g water 30 g 2 wt% sodium salt of dioctyl sulfosuccinate 0.3 g Polyvinyl alcohol 3 g, 100 g of water and 35 g of kaolin dispersed in a ball mill 3 g Hydrin Z-7 (trade name of Chukyo Yushi Co., Ltd.) 0.5 g ──────────────────────────────────

The obtained recording material was imagewise irradiated with a semiconductor infrared laser beam (GaAs junction laser) having a wavelength of 830 nm from the heat sensitive layer side to obtain a blue image. The output of the laser beam is at the surface of the heat-sensitive layer of the recording material,
The energy was adjusted to 40 mJ / mm ² in 1 millisecond. Then, the entire surface of the recording material was exposed and optically fixed using Ricopy Super Dry 100 (manufactured by Ricoh Co., Ltd.). The reflection density of the obtained blue recorded image was measured by a Macbeth reflection densitometer and found to be 1.12. The background density was 0.19.

Comparative Example 1. When a recording material was prepared and an image was recorded in the same manner as in Example 2 except that the quinoid dye used in Example 2 was not used, no image could be recorded.

Comparative Example 2. A recording material was prepared and an image was recorded in the same manner as in Example 1 except that a carbon black dispersion was used as an infrared absorbing pigment instead of the quinoid dye used in Example 1, and the obtained image was obtained. The transmission density was 1.24. The density of the background is 0.3
It was 1.

Comparative Example 3. Instead of the quinoid dye used in Example 1, bis (1-thio-) was used as an infrared absorbing dye.
A recording material was prepared in the same manner as in Example 1 except that 2-phenolate) nickel-tetrabutylammonium was used, and an image was recorded. The reflection density of the obtained image was 0.35. . The density of the background portion was 0.29.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C09B 57/00 A 7306-4H 6956-2H B41M 5/18 112

Claims (4)

[Claims] 1. A heat-sensitive layer containing, on a support, at least a substantially colorless color-forming component A, a substantially colorless color-forming component B that reacts with the color-forming component A to form a color, and an infrared absorbing dye. A thermal recording material for infrared laser, wherein the infrared absorbing dye is a quinoid dye represented by the following chemical formula 1 or chemical formula 2; [Chemical 2] In Chemical formula 2, Z is a substituted or unsubstituted 5- to 7-membered alicyclic or heterocyclic ring, and in Chemical formula 1 and Chemical formula 2, R is a hydrogen atom, or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. A group or an alkoxy group, or an aryl group or a hetaryl group having 5 to 10 carbon atoms, m is an integer of 0 to 4, and n is 0 to
It is an integer of 2. 2. The heat-sensitive recording material according to claim 1, wherein at least one of the color forming components A and B is microencapsulated. 3. The heat-sensitive recording material according to claim 1, wherein the color-forming component A is a photodecomposable diazo compound and the color-forming component B is a coupler. 4. 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 developer.