JPH04307292A - Thermal recording material for infrared laser - Google Patents

Abstract

PURPOSE:To provide a thermal recording material for infrared laser recording, with a background which does not become stained, capable of a recorded high- quality image and superb thermal sensitivity. CONSTITUTION:A thermal recording material for infrared laser consists of a thermal layer containing at least microcapsules containing color former and developer provided on a support. In addition, this material contains an infrared absorbing color in the wall of the microcapsule.

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 that records using an infrared laser beam.

0002

[Prior Art] A thermal recording method in which a thermal head is closely scanned on the surface of a thermosensitive recording material having a thermosensitive coloring layer provided on a support, and a colored image is recorded by transmitting thermal energy directly to the thermosensitive coloring layer or through a protective layer. is widely known and is applied to facsimiles, printers, etc. 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 may wear out or components of the thermal recording material may adhere to the surface of the thermal head in the form of debris. As a result, a recorded image may not be obtained correctly, and the thermal head is likely to be destroyed.

[0003] Furthermore, the thermal recording method using such a thermal head has limitations in controlling the heating and cooling of the heating element at high speed and increasing the density of the heating element due to the structural characteristics of the thermal head. The drawback was that there were limits to high-speed recording, high-density, and high-quality recording.

In order to solve the above-mentioned problems of the thermal recording method using a thermal head, it has been proposed to perform thermal recording on a thermal recording material in a non-contact manner at high speed and high density using a laser beam. (For example, Japanese Unexamined Patent Publication No. 5
0-23617, JP 54-121140, JP 57-11090, JP 58-56890, JP 58-94494, JP 58-134791, JP 58- No. 145493, JP-A-59-8919
No. 2, JP-A-60-205182, JP-A-62-56
Publication No. 195).

However, in such a recording method using a laser beam, the thermosensitive coloring layer generally has a
Since it is difficult to absorb light in the visible and near-infrared regions, it is difficult to obtain the thermal energy necessary for coloring unless the laser output is considerably increased, and it has the disadvantage that it is extremely difficult to create a small and inexpensive device. Ta.

[0006] Furthermore, Japanese Patent Publication No. 50-774 proposes a method in which microcapsules containing ink are applied to base paper, and intense light is irradiated to eject the ink in the capsules to record on the base paper. However, the sensitivity is very low and it has not yet been realized.

[0007]

[Problems to be Solved by the Invention] Therefore, many proposals have been made to make the thermosensitive coloring layer efficiently absorb the laser beam. Addition of substances is carried out.

In this case, if the light-absorbing substance added is not white, the background of the recording material will be colored and the contrast will be low.
This is undesirable because it results in poor quality recording, and if the added light-absorbing substance is not present in the area that requires direct heating, the resulting recording material has low sensitivity.

[0009] In general, white light-absorbing substances are often inorganic compounds, but since most of them have low light absorption efficiency, it has been desired to develop organic compounds with high light absorption efficiency and less coloring. .

However, since organic compounds that absorb light in the visible light range are generally colored, they are added to the recording layer as light-absorbing substances to increase the sensitivity and improve the whiteness of the recording paper. Although it is difficult to Even when added to the recording layer, it is possible to make the background of the recording material white.

Furthermore, when using microcapsules, a light-absorbing substance that absorbs the laser beam is generally added within the microcapsules containing the coloring agent or added to a heat-sensitive layer outside the microcapsules.

However, the mechanism of image recording using a laser beam is that the light-absorbing substance absorbs the laser beam irradiated in an imagewise manner, converts the energy of the laser beam into thermal energy, and heats the microcapsule wall. Accordingly, the image is recorded on the heat-sensitive recording material by bringing the reaction materials inside and outside the microcapsule into contact with each other. Therefore, if a light-absorbing substance is added near or within the microcapsule wall, the microcapsule wall can be directly heated by a laser beam, thereby improving the sensitivity of the heat-sensitive recording material.

[0013] Therefore, the present inventors separated the two coloring components contained in the heat-sensitive layer by microcapsules, contained an infrared absorbing dye in the wall of the microcapsules, and recorded using an infrared laser. The inventors have discovered that very good results can be obtained by carrying out the following steps, and have thus arrived at the present invention. Therefore, an object of the present invention is to provide a heat-sensitive recording material for infrared laser recording which is highly sensitive and capable of high-quality recording with less coloring of the background.

[0014]

[Means for Solving the Problems] The above objects of the present invention are as follows:
A heat-sensitive recording material for an infrared laser, comprising, on a support, microcapsules containing at least a color former and a heat-sensitive layer containing a color developer, the microcapsules having an infrared absorbing dye in their walls. This was achieved by a heat-sensitive recording material for infrared laser, which is characterized by containing.

[0015] The color former and color developer used in the present invention are components that cause a color reaction based on contact of substances. ) or a combination of a diazo compound (color former) and a coupling compound (color developer) are preferred.

[0016] The electron-donating dye precursor used in the present invention is not particularly limited, but it has the property of donating electrons or accepting protons such as acids to develop color. Compounds that are substantially colorless and have partial skeletons such as lactones, lactams, sultones, spiropyrans, esters, and amides, and whose partial skeletons open or cleave when contacted with a color developer are used.

Specifically, crystal violet lactone, benzoylleucomethylene blue, malachite green lactone, rhodamine B lactam, 1,3,3-
Examples include trimethyl-6'-ethyl-8'-butoxyindolinobenzospiropyran.

Color developers for these color formers include:
Acidic substances such as phenol compounds, organic acids or metal salts thereof, and oxybenzoic acid esters are used, and specific examples thereof are described, for example, in JP-A-61-291183.

The diazo compound used in the present invention develops a desired hue by reacting with a color developer called a coupling component, which will be described later, and decomposes when exposed to light of a specific wavelength before the reaction. However, it is a photodegradable diazo compound that no longer has color-forming ability even when a coupling component acts on it.

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. 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.

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

The diazonium salt has the general formula ArN2 +
It is a compound represented by X- (wherein Ar represents a substituted or unsubstituted aromatic moiety, N2 + represents a diazonium group, and X- represents an acid anion).
.

It is generally said that the photodecomposition wavelength of a diazonium salt is its maximum absorption wavelength. It is also known that the maximum absorption wavelength of diazonium salts varies from about 200 nm to about 700 nm depending on its chemical structure ("Photodegradation and chemical structure of photosensitive diazonium salts" by Takahiro Tsunoda and Ao Yamaoka, Nippon Photo) Academic Journal 29(4) 197-2
05 page (1965)). That is, if a diazonium salt is used as a photodegradable compound, it will be decomposed by light of a specific wavelength depending on its chemical structure, and if the chemical structure of the diazonium salt is changed, it will be decomposed by light of a specific wavelength depending on its chemical structure. The hue of the pigment also changes.

As the light source for photolysis, various light sources that emit light of a desired wavelength can be used, such as various fluorescent lamps, xenon lamps, xenon flash lamps, mercury lamps of various pressures, photographic flashes, Various light sources such as strobes can be used. 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.

A large number of diazosulfonates that can be used in the present invention are known, and can be obtained by treating each diazonium salt with a sulfite. Further, other diazo compounds that can be used in the present invention include diazoamino compounds. The diazoamino compound is a compound in which a diazo group is coupled with dicyandiamide, sarcosine, methyltaurine, N-ethylanthranic acid-5-sulfonic acid, monoethanolamine, diethanolamine, guanidine, or the like. Details of these diazo compounds are described, for example, in JP-A-2-136286.

Coupling components that form a dye by coupling with the diazo compound (diazonium salt) used in the present invention include, for example, 2-hydroxy-3-naphthoic acid anilide, as well as resorcinol and other compounds disclosed in JP-A-62 -14
Examples include those described in No. 6678.

Furthermore, by using two or more of these coupling components in combination, an image of any color tone can be obtained. 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 the basic substance, a poorly water-soluble or water-insoluble basic substance or a substance that generates an alkali when heated is used. Examples include inorganic and organic ammonium salts, organic amines, amides, urea and thiourea and their derivatives, thiazoles, pyrroles, pyrimidines,
Piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles, morpholines, piperidines, amidines, formazines,
Examples include nitrogen-containing compounds such as 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 infrared absorbing dye used in the present invention is preferably a dye that has a low absorption of light in the visible wavelength range but a particularly high absorption of light in the infrared wavelength range, and in particular, a dye that absorbs light of wavelengths in the infrared range. It is preferable to have an active group that reacts with the material.

Specific examples of the above-mentioned active groups include isocyanate groups, hydroxy groups, mercapto groups, amino groups, etc., with isocyanate groups and hydroxy groups being particularly preferred. Among the above-mentioned infrared absorbing dyes, it is particularly preferable to use cationic dyes, complex salt-forming dyes, and quinone neutral dyes described in detail below.

The cationic dye is a dye represented by the following general formula (1). D1 + [X1 -1/ m ] m (1) However, D1 + represents a cationic dye nucleus, X1 - represents a counter anion, and m represents an integer of 1 to 4.

D1 +, which is the cationic pigment nucleus in the general formula (1), includes polymethine (containing cyanine),
Preferred are azulenium, pyrylium, thiopyrylium, squarylium, triarylmethane, immonium, diimmonium, and the like. X-1/m is not particularly limited as long as it can form a counter anion, and the active group that reacts with the microcapsule wall is D1 + or X1 -1
/m.

Specific examples of the above cationic dyes include:
Examples include dyes represented by the following formulas. Polymethine (cyanine) dye:

[Chemical formula 1]

[Case 2]

[Chemical formula 3]

[C4] However, n=2 or 3.

[C5] However, n=2 or 3.

[C6]

[C7]

[Chemical formula 8]

[Chemical formula 9]

[Chemical formula 10]

[0034] Azulenium dye:

[Chemical formula 11] Pyrylium, thiopyrylium pigments:

[Chemical formula 12] However, Y is O or S. Squalium pigment:

[
Chemical 13]

[0035] Triarylmethane dye:

[Chemical formula 14]

[Chemical formula 15]

[Chemical formula 16]

[Chemical formula 17]

Immonium, diimmonium dye:

[
18]

[Chemical formula 19]

[C20]

[C21]

[0037] As the complex salt dye, thiol nickel complex salt dye and phthalocyanine dye are preferable. Specific examples of the above-mentioned complex salt dyes include dyes represented by the following formulas.

[0038] Thiol nickel complex salt dye:

[C22]

[C23]

[C24] However, M is Ni or Pt.

[C25]

[0039] Phthalocyanine dye:

embedded image However, R is H or —CH2 CH2 OH, and M is Ni or Pt.

[C27] However, M is Ni or Pt.

[0040] Naphthalocyanine dye:

embedded image However, M is Ni or Pt. As the quinone-based neutral dye, naphthoquinone-based and anthraquinone-based dyes are preferred.

Specific examples of the naphthoquinone neutral dye include dyes represented by the following formula.

[C29] However, R is H or -CH2CH2OH.

[C30]

[0042] Anthraquinone dye:

[Chemical formula 31]

[C32]

[Chemical formula 33]

The color former used in the present invention is selected from the viewpoint of improving the transparency of the recording layer, from the viewpoint of storage stability (fogging prevention) such as preventing contact between the color former and the color developer at room temperature, and from the viewpoint of desired laser energy. The color former is encapsulated and used from the viewpoint of controlling the sensitivity of color development.

Any of the interfacial polymerization method, internal polymerization method, and external polymerization method can be used to produce the microcapsules used in the present invention, but in particular, the core material containing the coloring agent is made water-soluble. It is preferable to employ an emulsion polymerization method in which a polymer is emulsified in an aqueous solution in which a polymer is dissolved, and then a wall of the polymer material is formed around the oil droplets.

[0045] A reactant forming a polymeric substance is added to the interior of the oil droplet and/or to the exterior of the oil droplet. Specific examples of the polymeric material include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene-methacrylate copolymer, styrene-acrylate copolymer, and the like. Preferred polymeric materials are polyurethanes, polyureas, polyamides, polyesters, polycarbonates, particularly preferred are polyurethanes and polyureas. Two or more types of polymeric substances can also 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 diisocyanates, triisocyanates, tetraisocyanates, and polyisocyanate prepolymers, polyamines such as diamines, triamines, and tetraamines, and two amino groups are used. A microcapsule wall can be easily formed by reacting the prepolymer, piperazine or its derivative, polyol, etc. contained above in an aqueous solvent by an interfacial polymerization method.

[0047] Furthermore, for example, a composite wall made of polyurea and polyamide or a composite wall made of polyurethane and polyamide can be prepared by using, for example, polyisocyanate and acid chloride, or polyamine and polyol, after adjusting the pH of the emulsifying medium to be the reaction solution. It can be prepared by heating. For details on the manufacturing method of these composite walls made of polyurea and polyamide, please refer to JP-A-58-6
It is described in Japanese Patent No. 6948.

[0048] Furthermore, the infrared absorbing dye described above is added to the microcapsules used in the present invention at the time of forming the microcapsule wall, and the infrared absorbing dye having the active group is reacted with the microcapsule wall material. Contain.

Furthermore, optional additives such as metal-containing dyes and nigrosine can be added to the microcapsule walls used in the present invention, if necessary. These additive substances can be incorporated into the capsule wall during wall formation or at any other time. Furthermore, a solid sensitizer can be added to swell the microcapsule walls during laser beam heating.

[0050] The solid sensitizer can be selected from those called plasticizers for the polymer used as the microcapsule wall, and has a melting point of 50°C or higher, preferably 120°C or lower, and is solid at room temperature. . For example, when the wall material is made of polyurea or polyurethane, hydroxy compounds, carbamate ester compounds, aromatic alkoxy compounds, organic sulfonamide compounds, aliphatic amide compounds, aryl amide compounds, etc. are preferably used.

In the present invention, when a diazo compound is used as a coloring agent, it is also possible to use a coloring aid. The color development aid that can be used in the present invention is a substance that increases the color density during laser heating printing or lowers the minimum color development temperature, lowers the melting point of coupling components or diazo compounds, etc. This is to create a situation where the diazo compound and the coupling component are likely to react by lowering the softening point of the wall.

Color development aids include phenolic compounds, 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-
Compounds such as methanesulfonic acid amide and N-phenyl-methanesulfonic acid amide can be mentioned. These may be contained in the core material or may be added outside the microcapsules as an emulsified dispersion.

In the present invention, the color developer is dissolved in an organic solvent that is sparingly soluble or insoluble in water, and then mixed with an aqueous phase having a water-soluble polymer containing a surfactant as a protective colloid. , can be used in the form of an emulsified dispersion.

The organic solvent used in this case can be appropriately selected from high boiling point oils. In addition to esters, preferred oils include 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 (e.g. tritolylmethane, tolyldiphenylmethane), terphenyl compounds (
terphenyl), alkyl compounds (e.g. terphenyl), alkylated diphenyl ethers (e.g. propyl diphenyl ether), hydrogenated terphenyl (e.g.
Examples include hexahydroterphenyl), diphenyl ether, and the like. Among these, it is particularly preferable to use esters from the viewpoint of emulsion stability of the emulsified dispersion.

Examples of esters include phosphate esters (for example, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, cresyl diphenyl phosphate), phthalate esters (dibutyl phthalate, 2-ethylhexyl phthalate, phthalate). ethyl, octyl phthalate, butyl benzyl phthalate), dioctyl tetrahydrophthalate, benzoic acid ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate), abietic acid ester (ethyl abietate, benzyl abietate), dioctyl adipate,
Isodecyl succinate, dioctyl azelaate, oxalate esters (dibutyl oxalate, dipentyl oxalate)
, diethyl malonate, maleate esters (dimethyl maleate, diethyl maleate, dibutyl maleate)
, tributyl citrate, sorbate esters (methyl sorbate, ethyl sorbate, butyl sorbate), sebacate esters (dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (formic acid monoesters 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, propylene carbonate, boric acid esters tributyl acid, tripentyl borate), etc. Among these, when tricresyl phosphate is used alone or in combination, the emulsion dispersion stability of the color developer is particularly good, and therefore it is preferable.

[0056] It is also possible to use the above oils together or with other oils. In the present invention, an auxiliary solvent may be added to the above-mentioned organic solvent as a low boiling point dissolution aid. Particularly preferred examples of such co-solvents include ethyl acetate, isopropyl acetate, butyl acetate and methylene chloride.

The water-soluble polymer to be contained as a protective colloid in the aqueous phase to be 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, etc. are preferred.

[0058] The surfactant to be contained in the aqueous phase may be appropriately selected from anionic or nonionic surfactants that do not interact with the protective colloid to cause precipitation or aggregation. can. Preferred surfactants include sodium alkylbenzene sulfonate, sodium alkyl sulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (eg, polyoxyethylene nonylphenyl ether), and the like.

[0059] The emulsified dispersion in the present invention is produced by combining an oil phase containing the above components and an aqueous phase containing a protective colloid and a surfactant using means commonly used for fine particle emulsification, such as high-speed stirring and ultrasonic dispersion. It can be mixed and dispersed easily.

[0060] The ratio of the oil phase to the aqueous phase (oil phase weight/aqueous phase weight) is preferably from 0.02 to 0.6, particularly from 0.02 to 0.6.
．． It is preferable that it is 1-0.4. If it is less than 0.02, the aqueous phase is too large and diluted, and sufficient color development cannot be obtained;
．． On the contrary, if it is 6 or more, the viscosity of the liquid increases, resulting in inconvenience in handling and decreased stability of the coating liquid.

[0061] When the heat-sensitive layer solution prepared as described above is applied onto a support, a known coating means using a water-based or organic solvent-based coating solution is used. In this case, in order to safely and uniformly apply the heat-sensitive layer liquid and maintain the strength of the coating film, in the present invention, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, polyvinyl alcohol, 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, polyamide resins, etc. are used together with microcapsules. You can also.

The support used in the present invention may be transparent or opaque. When using a transparent support that exhibits no absorption at the wavelength of the irradiated laser beam, does not deform due to heat generated during laser irradiation, and has dimensional stability, the laser beam can be irradiated through the transparent support. It can also be irradiated and recorded. The thickness of the support is 10
Those with a diameter of μm to 200 μm are used.

Examples of such transparent supports include:
Polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate films, polyolefin films such as polystyrene films, polypropylene films, and polyethylene films, polyimide films, polyvinyl chloride films, polyvinylidene chloride films,
Examples include polyacrylic film and polycarbonate film, and these 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-deposited base, and the transparent support coated with a pigment or the like. In this case,
In order for the laser beam to be irradiated from the heat-sensitive layer side and efficiently absorbed by the heat-sensitive layer, it is preferable to use a material that is highly reflective to the laser beam as the opaque support for the recording material.

The support used in the present invention is particularly preferably a polyester film subjected to heat-resistant treatment and antistatic treatment. In the present invention, in order to prevent the whole heat-sensitive layer from peeling off from the support, it is desirable to provide an undercoat layer on the support before coating the heat-sensitive layer containing microcapsules or the like on the support.

[0066] As the undercoat layer, acrylic ester copolymer, polyvinylidene chloride, SBR, water-based polyester, etc. can be used, and the film thickness is 0.1-0.
5 μm is desirable.

The undercoat layer made of these compositions is applied by a known coating method such as a blade coating method, an air knife coating method, a gravure coating method, a roll coating method, a spray coating method, a dip coating method, or a bar coating method. be done. The coating amount is preferably 1 to 20 g/m2, particularly 3 to 10 g/m2.
It is preferable to set it as g/m2.

Further, pigments, waxes, hardeners, etc. may be added to the heat-sensitive layer, if necessary. The heat-sensitive layer is a coloring agent,
The total amount of color developer and infrared absorbing dye is 0.1 to 10 g/m
2 and the thickness of the layer is 1
It is desirable that the coating be applied to a thickness of ~10 μm.

Furthermore, in order to prevent the dye from being physically transferred due to adhesion to the heat-sensitive layer, a slipping agent such as wax may be applied. 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 laser, a YAG laser, and a semiconductor laser.

Since the heat-sensitive layer of the recording material of the present invention contains an infrared absorbing dye in the microcapsule wall, when a laser beam is irradiated, the infrared absorbing dye contained in the microcapsule wall absorbs the laser beam. absorbs and converts that energy into thermal energy. As a result, the microcapsule wall is directly heated and becomes permeable to the substance, and as a result, the reactant inside and outside the microcapsule comes into contact and develops color.

[0071] In this case, compared to the case where an infrared absorbing dye is added inside or outside the microcapsule, the microcapsule wall is heated more directly by the laser beam, so the sensitivity of thermal recording is greatly improved. . Sensitivity can be further improved by coexisting an infrared absorbing substance not only in the microcapsule wall but also inside or outside the microcapsule.

Further, when a coating liquid containing a color developer as an emulsion is applied, the transparency of the heat-sensitive layer can be increased. In addition, since the microcapsule wall contains an infrared absorbing dye that absorbs infrared rays particularly well while light absorption in the visible light region is low, the absorption efficiency of upper infrared laser is high with little coloring of the background of the recording material.

[0073]

Effects of the Invention In the heat-sensitive recording material of the present invention, the microcapsules contained in the heat-sensitive layer contain an infrared-absorbing dye that absorbs infrared rays particularly well in the microcapsule walls, so that the microcapsule walls are easily absorbed by an infrared laser beam. Since it is directly heated, it has good thermal sensitivity. Further, by selecting an infrared absorbing dye to be used that does not have absorption in the visible region, it is possible to prevent the background of the recording material from being colored.

[0074]

[Examples] The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited thereby. Note that "parts" indicating the amount added indicate "parts by weight."

(Example 1) Preparation of capsule liquid 14 g of crystal violet lactone (leuco dye), 60 g of Takenate D-110N (trade name of capsule wall material manufactured by Takeda Pharmaceutical Company Limited) and 2 g of an infrared absorbing dye having the following structural formula were added. ,

[0076]

embedded image It was added to and dissolved in a mixed solvent of 55 g of 1-phenyl-1-xylylethane and 55 g of methylene chloride. The obtained solution was diluted with 8% by weight polyvinyl alcohol aqueous solution 100% by weight.
g, mixed with an aqueous solution of 40 g of water and 1.4 g of 2% by weight sodium salt of dioctyl sulfosuccinate (dispersant), and emulsified for 5 minutes at 10,000 rpm using an Ace homogenizer (manufactured by Nippon Seiki Co., Ltd.). Ta. 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 liquid with an average particle size of 0.7 μm.

Preparation of color developer emulsion dispersion 8 g of color developer (a) represented by the following chemical formula,

[C35] 4 g of color developer (b) represented by the following chemical formula,

[C36] and 30 g of color developer (c) represented by the following chemical formula,

[C3
7] was dissolved in a mixture of 8.0 g of 1-phenyl-1-xylylethane and 30 g of ethyl acetate.

The obtained solution was mixed with an aqueous solution of 100 g of 8% by weight polyvinyl alcohol aqueous solution, 150 g of water, and 0.5 g of sodium dodecylbenzenesulfonate, and then mixed using an Ace homogenizer (manufactured by Nippon Seiki Co., Ltd.).
Emulsification was performed at 10,000 rpm for 5 minutes at room temperature so that the average particle size was 0.5 μm to obtain an emulsified dispersion.

Preparation of heat-sensitive recording material: 5.0 g of the above capsule liquid, 10 g of the above color developer emulsified dispersion.
Stir and mix 0g of water and 5.0g of water to a thickness of 70μ.
After coating on a transparent polyethylene terephthalate (PET) support with a solid content of 15 g/m2 and drying, a layer as shown in Table 1 below was applied on the heat-sensitive layer formed as described above. The protective layer liquid of the composition has a thickness of 2 after drying.
A transparent heat-sensitive recording material according to the present invention was prepared by coating and drying to a thickness of μm.

[0080]

[Table 1] ──────────────────────────
────────── Composition of protective layer liquid 10% by weight polyvinyl alcohol
20g water


30g 2% by weight sodium salt of sulfosuccisandioctyl 0.3g polyvinyl alcohol 3g, water 100g and kaolin 35g
Kaolin dispersion made by dispersing in a ball mill

3g Hydrin Z-7 (manufactured by Chukyo Yushi Co., Ltd.)
0.5g──────────────────
────────────────────

A semiconductor laser beam (AlGaAs bonding laser) having a wavelength of 780 nm was irradiated imagewise from the heat-sensitive layer side of the heat-sensitive recording material produced as described above to obtain a blue recorded image. The laser output is 35 times per millisecond at the surface of the heat-sensitive layer.
The energy was adjusted to be mJ/mm2. The reflection density of the colored portion of the obtained image was measured using a Macbeth densitometer and found to be 1.47.

(Example 2) Instead of the crystal violet lactone used in Example 1, 2-anilino-3
A heat-sensitive recording material was prepared in exactly the same manner as in Example 1 except that -methyl-6-N-ethyl-N-butylaminofluorane was used, and an image was recorded to obtain a transparent black image. The transmission density of the colored portion of the obtained image was measured using a Macbeth densitometer and found to be 1.63.

(Example 3) A developer dispersion having a particle size of 2 μm was prepared by dispersing the composition shown in Table 2 below using a ball mill.

[0084]

[Table 2] Dispersion ────────────────────────Polyvinyl allure
5g Color developer (a) with the following chemical formula
4g

[Chemical formula 38] Color developer (b) 2 of the following chemical formula
g

[Chemical formula 39] 15 g of color developer (c) with the following chemical formula

[C40] Water
100g────────────────
────────

Obtained color developer dispersion 9
g, a liquid obtained by stirring and mixing 5 g of the capsule liquid prepared in Example 1 and 5 g of water was placed on a transparent polyethylene terephthalate (PET) support with a thickness of 70 μm, with a solid content of 15 g.
A recording material was prepared in exactly the same manner as in Example 1, except that coating and drying was carried out so that the coating film was coated and dried so as to obtain a transparent blue image. The transmission density of the colored portion of the obtained image was measured using a Macbeth densitometer and found to be 1.63.

(Example 4) In place of the infrared absorbing dye used in Example 2, an infrared absorbing dye having the following structural formula was used.

[C41
] A heat-sensitive recording material was prepared in exactly the same manner as in Example 2, except that the material was used, and an image was recorded to obtain a transparent black image. The transmission density of the colored portion of the obtained image was measured using a Macbeth densitometer and found to be 1.57.

(Example 5) Preparation of capsule liquid The following chemical formula

[C42] To 50 parts of the compound, the following chemical formula is added.

5 parts of infrared absorbing dye of [Chemical formula 43], 150 g of methylene chloride,
50 parts of tricresyl phosphate, 150 parts of trimethylolpropane trimethacrylate, 75% by weight ethyl acetate solution of trimethylolpropane 3:1 adduct of m-xylylene diisocyanate (Takenate D110N: trade name manufactured by Takeda Pharmaceutical Company Limited) ) were uniformly mixed to prepare an oil phase solution.

On the other hand, 7% by weight of polyvinyl alcohol (PVA217E: degree of oxidation 88-89%, degree of polymerization 1,
700: trade name manufactured by Kuraray Co., Ltd.) 600 parts were prepared to form a water-soluble polymer aqueous solution.

Next, a dissolver was attached to a 5 liter stainless steel pot equipped with a hot bath, and after the aqueous polymer solution was added, the oil phase solution was added while stirring the dissolver, and the emulsion was observed under a microscope. Emulsification and dispersion was performed so that the average particle size of the particles was approximately 1.5 μm. After the dispersion was completed, the stirring was loosened and 42°C hot water was passed into the hot bath, and the temperature inside the pot was maintained at 40°C to complete the encapsulation reaction in 3 hours. Ion exchange resin MB- is added to the obtained liquid.
After adding 25 ml of No. 3 (trade name manufactured by Organo Co., Ltd.) and stirring, the mixture was filtered to obtain a capsule liquid.

Preparation of Dispersion A: The substances shown in Table 3 below were mixed and dispersed in advance using a dissolver.
．． A dispersion liquid A was obtained by emulsifying and dispersing the dispersion liquid to an average particle size of 2 μm.

[0091]

[Table 3] ──────────────────────────
──────────── 15% by weight polyvinyl alcohol aqueous solution (PVA-205 manufactured by Kuraray Co., Ltd., product name)

30 parts Coupler of the compound of the following chemical formula
4. Part 3

[Chemical formula 44] Coupler of the compound of the following chemical formula
0.6 parts

[Chemical formula 45] Organic basic compound of the following chemical formula
5.0 copies

[Chemical formula 46] Color development improver having the following chemical formula
3.
0 copies

[C47] ──────────────────────────
────────────

Preparation of dispersion B Dispersion B was obtained by mixing and stirring the materials shown in Table 4 below.

[0093]

[Table 4] ──────────────────────────
──────────── Univer 70 (Product name manufactured by Shiraishi Kogyo Co., Ltd.)
Part 20 Kaobrite (Thiele Kaolin)
40% by weight of Company (product name)
Sodium hexametaphosphate aqueous solution
0.5 part water

Part 30────────────────────────
────────────

Preparation of heat-sensitive recording material 20 parts of the capsule liquid, 20 parts of Dispersion A, 7 parts of Dispersion B, and 1.5 parts of a 2% by weight aqueous solution of Nissan Rapizole 13-90 (trade name, manufactured by NOF Corporation) were stirred. Mixed with polyethylene terephthalate (PET) with a thickness of 70 μm.
) was coated and dried to provide a recording layer at a solid content of 15 g/m 2 . Furthermore, a protective layer was provided by coating a mixture having the composition shown in Table 5 below to a thickness of 2 μm on the recording layer, thereby producing a recording material.

[0095]

[Table 5] Composition of protective layer ────────────────────────
──────────10% by weight polyvinyl alcohol
20g water

30g2
Weight% Dioctyl Sulfosuccinate Sodium Salt
Kaolin dispersion made by dispersing 0.3g polyvinyl alcohol 3g, water 100g and kaolin 35g using a ball mill.

3g Hydrin Z-7 (product name manufactured by Chukyo Yushi Co., Ltd.) 0.5g
──────────────────────────
────────────

The obtained recording material was injected with semiconductor infrared laser light (AlGa
A blue image was obtained by irradiating the recording layer with As bonding laser) from the recording layer side in an imagewise manner. The output of the laser beam was adjusted to provide an energy of 35 mJ/mm 2 for 1 millisecond at the surface of the recording layer of the recording material. Next, the entire surface of the recording material was exposed to light using Ricopy Super Dry 100 (manufactured by Ricoh Co., Ltd.) for optical fixation. The reflection density of the obtained blue recorded image was measured with a Macbeth reflection densitometer and was found to be 1.13.

(Example 6) Preparation of capsule liquid 14 g of 2-anilino-3-methyl-6-N-ethyl-N-butylaminofluorane (leuco dye), Takenate D-110
50 g of N (product name of capsule wall material manufactured by Takeda Pharmaceutical Co., Ltd.) and 5 g of an infrared absorbing dye of the following chemical formula,

embedded image It was added to a mixed solvent of 55 g of 1-phenyl-1-xylylethane and 55 g of methylene chloride to dissolve it.

The obtained solution was mixed with 100 g of an 8% by weight polyvinyl alcohol aqueous solution, 40 g of water, and 1.4 g of 2% by weight sodium salt of dioctyl sulfosuccinate (dispersant).
The mixture was mixed with an aqueous solution of 1, and then emulsified for 5 minutes at 10,000 rpm using an Ace homogenizer (manufactured by Nippon Seiki Co., Ltd.). After adding 150 g of water to the obtained emulsion, an encapsulation reaction was carried out at 40°C for 3 hours to reduce the average particle size to 0.
．． A 7 μm capsule solution was prepared.

Example 1 was completed except that the capsule liquid obtained above was used instead of the capsule liquid used in Example 1.
A recording material was produced in the same manner as described above, and a transparent black image was obtained. The color development area of the obtained image was measured with a Macbeth transmission densitometer and found to be 1.52.

(Comparative Example 1) A recording material was prepared in exactly the same manner as in Example 1 except that the infrared absorbing dye used in Example 1 was not used, and an image was recorded. However, no image could be recorded.

(Comparative Example 2) A recording material was prepared in exactly the same manner as in Example 1 except that the infrared absorbing dye used in Example 5 was not used, and an image was recorded. However, no image was recorded.

Claims (2)

[Claims] 1. A heat-sensitive recording material for an infrared laser, comprising, on a support, microcapsules containing at least a color former and a heat-sensitive layer containing a color developer, wherein the microcapsules are formed on the walls of the microcapsules. A heat-sensitive recording material for infrared lasers, characterized by containing an infrared-absorbing dye therein. 2. The heat-sensitive recording material for an infrared laser according to claim 1, wherein the infrared absorbing dye has an active group that reacts with the microcapsule wall material.