JP2965924B2 - Multicolor thermal recording material - Google Patents

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 having a heating element such as a thermal head and used in a recording apparatus for forming a thermal image by applying heat, which is received from a thermal head or the like. The present invention relates to a multicolor heat-sensitive recording material that has at least two color-forming layers that develop different colors depending on the amount of heat energy and that forms a color image of two or more colors.

[0002]

2. Description of the Related Art Thermal paper using a leuco dye and its color developer, which develops a color when heat is applied by a heating element of a thermal head, is well known. This thermal paper is widely used as a recording material for facsimile machines, printers, and the like because of its compact size, easy maintenance, low cost of paper, and simplicity of use.

On the other hand, recording of a single color such as black or blue has been mainly used in the past, but with the expansion of the use of the recording apparatus, demands for multi-color and further full-color image recording materials have been increasing in recent years. . In recent years, technologies such as laser electrostatic recording, ink jet, and transfer thermosensitive film have been used for these applications, but the demand for multicolor image recording materials utilizing the properties of thermosensitive paper has been particularly increasing. ing. That is, the thermal energy applied by the thermal head is changed to form multicolor image recording.

For this purpose, attempts have been made to change the color tone in accordance with the energy applied from a thermal head or the like, using a leuco dye and its developer used in thermal paper. I have. As one method, there is a method of forming a low-temperature coloring layer and a high-temperature coloring layer having different color tones and changing the color by heating. In this case, high-temperature coloring also occurs at the same time as low-temperature coloring.
It is a mixture of high-temperature color tones, merely changing the hue by mixing the colors, and it is not possible to obtain the color hue of each heat-sensitive layer.

In order to improve this point, a low-temperature coloring layer is erased by using a decoloring agent having a decoloring effect on the color-forming body of the low-temperature recording layer at the time of high-temperature heating, and the coloring of only the high-temperature coloring layer is performed. How to get it has been proposed. Regarding the multicolor heat-sensitive recording material using the decoloring agent, for example, JP-B-54-36836, JP-A-55-7449, JP-A-55-7450, JP-B
4-32752 JP, JP-A-5-185715, JP-A-5-15-1
No. 93254, JP-A-5-201127 and the like. However, it is still insufficient to completely separate the color hues, complete prevention of color mixing has not been achieved, and it has been extremely difficult to obtain a multicolor heat-sensitive recording material of three or more colors. Further, there has been a problem that the image recording gradually colored by the decoloring agent is discolored, faded or mixed in color with the elapse of time after the color development.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a multicolor heat-sensitive recording material having a different color tone due to a difference in heat applied energy, and solves the above-mentioned problems.
An object of the present invention is to provide a multicolor heat-sensitive recording material which is excellent in stability of color image recording and can obtain full color image recording with less color mixture.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above-mentioned object, and as a result, have found that each of the conventional color developing papers containing a leuco dye and its color developer containing a color developing agent. A heat-sensitive coloring layer having a different color tone, and a sublimation dye coloring layer formed by combining a layer containing a sublimable dye and a dye fixing layer in the lowermost layer, and a hue of a low-temperature coloring portion when coloring at a high temperature. By having microcapsules containing a decoloring agent for decoloring in or near the thermosensitive coloring layer containing the leuco dye and the developer,
By using a printer with a heating element such as a thermal head and changing the applied energy,
It has been found that multi-color to full-color image recording with little color mixture can be obtained.

That is, a support (a), a sublimable dye coloring layer (b) formed on the support, and at least one leuco dye coloring layer (c) formed on the sublimable dye coloring layer. A multicolor heat-sensitive recording material comprising:
(b) has a two-layer structure of a sublimable dye layer, a thermoplastic resin to which the sublimable dye is fixed, and a sublimable dye fixing layer made of titanium oxide that conceals the hue of the sublimable dye, and the leuco dye coloring is performed. Layer (c) contains a leuco dye and a developer, and microcapsules containing a decoloring agent for coloring of the leuco dye are present as a separate layer in or near the leuco dye coloring layer, The coloring of the leuco dye coloring layer (c) occurs when a temperature lower than the coloring temperature of the sublimable dye coloring layer (b) is applied, and at the temperature at which the sublimable dye coloring layer (b) develops, the leuco dye coloring layer (c The present invention relates to a multicolor heat-sensitive recording material characterized in that the color development of (1) is decolorized by the collapse of the decolorizing agent microcapsules.

An example of a typical configuration of the present invention will be described with reference to FIG. On a support a such as a high quality paper or a polyester resin film, a lowermost sublimable dye coloring layer b composed of a sublimable dye layer 1 and a sublimable dye fixing layer 2 is formed. Sublimable dye coloring layer b containing a leuco dye and a developer thereon
To form a medium-temperature coloring leuco dye coloring layer c1 having a different coloring hue. A microcapsule 3 containing a decoloring agent for this color formation is provided therein or in the vicinity thereof. FIG. 1 shows a case where the decoloring agent is present as a layer different from the leuco dye layer. Further, a leuco dye and a color developer are contained thereon, and a sublimation dye coloring layer b and a medium-temperature coloring leuco dye coloring layer are formed thereon.
A low-temperature coloring leuco dye coloring layer c2 having a coloring hue different from that of c1 is formed. Similarly, a microcapsule 4 containing a decoloring agent for the low-temperature coloring layer c2 is provided therein or in the vicinity thereof. FIG. 1 shows a case where the decoloring agent is present as a layer different from the leuco dye layer. With this configuration, low to high temperature 3
By applying different types of thermal energy to the surface, it is possible to obtain a heat-sensitive recording material 10 that develops three colors with each color tone separated.

When a low heat energy is applied, only the portion of the uppermost layer of the low-temperature leuco dye coloring layer c2 to which the thermal energy is applied develops a color. When moderate heat energy is applied, the decapsulating agent-encapsulated microcapsules 4 in or near the uppermost layer are broken or swelled to release the decoloring agent, thereby erasing the low-temperature coloring image, and at the same time, the medium-temperature coloring leuco dye The color-forming layer c1 develops color, and an image record of only a medium-temperature color hue having a different hue from the low-temperature color-recorded image can be obtained without mixing the two color tones. Similarly, the portion to which higher heat energy is applied similarly destroys or swells the microcapsules 3 in or near the medium-temperature coloring leuco dye coloring layer and releases the decoloring agent, thereby erasing the image of the medium-temperature coloring leuco dye coloring layer. I do. At the same time, the lowermost sublimable dye coloring layer b develops a color, and an image of only the sublimable dye having a hue different from low-temperature and medium-temperature coloring images can be obtained. Thus, the portion where no heat energy is applied remains unchanged and remains white, the portion where only low heat energy is applied shows the hue of the low-temperature leuco dye coloring layer c2, and the portion where medium energy is applied is medium temperature. Only the image recording of the hue of the color forming leuco dye coloring layer c1 is obtained, and the image recording of only the hue of the sublimable dye coloring layer b is obtained in the portion where the high heat energy is applied.

The above example shows one embodiment of the heat-sensitive recording material of the present invention in which three layers are formed by forming two leuco dye coloring layers. Of course, only one leuco dye coloring layer was formed. In this case, it is possible to obtain a thermosensitive recording material which develops two colors by a leuco dye coloring layer and a sublimable dye coloring layer,
If the leuco dye coloring layer is further increased, a multicolor heat-sensitive recording material of three or more colors can theoretically be obtained.

The microcapsules enclosing the decolorizing agent may be uniformly dispersed in the low- and medium-temperature leuco dye coloring layers, or may be above and / or below the low- and medium-temperature leuco dye coloring layers, respectively. A decoloring layer containing microcapsules containing a decoloring agent may be separately formed and present. Since the decoloring agent is protected by the microcapsules, it is stable. From the viewpoint of the decoloring effect, it is preferable that the decolorizing agent microcapsules are uniformly present inside the leuco dye coloring layer.

The leuco dye used in the leuco dye coloring layer in the present invention includes triarylmethane, diphenylmethane, xanthene, thiazine, and spiropyran compounds.
Numerous leuco dyes are exemplified in JP-A No. 27, JP-B 5-71395, and the like, and various known colorless or light-colored leuco dyes described therein can be used. These disclosures are incorporated herein by reference. Of course, the present invention is not limited to the leuco dye disclosed herein, and two or more of them may be used in combination from the viewpoint of color tone and decoloring effect, if necessary. The color development temperature of the leuco dye can be controlled by using a sensitizer. In the case of FIG. 1 described above as an example, the leuco dye coloring layer c2 is 80 to 95 ° C., preferably 85 to 95 ° C.
It is preferable that the color develops between ℃ and 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (CVL) which is a leuco dye and dibenzyl oxalate as a sensitizer And the like. Leuco dye coloring layer c1
It develops color at 105-120 ° C, preferably between 110-120 ° C,
The color development temperature difference from that used for c2 is 10 to 40 ° C, preferably
Those having a temperature of 20 to 40 ° C. are preferred, and specific examples thereof include 3-diethylamino-6-methylfluoran and 3-diethylamino-5-ethyl-7-chlorofluoran.

As for the color developer used in combination with the above-mentioned leuco dye, many various materials such as phenol, triphenylmethane, sulfur-containing phenol, carboxylic acid, sulfone, urea or thiourea compounds are known. For example, Japanese Patent Application Laid-Open No. 5-201127, Japanese Patent Publication No. 5-71395, and the Pulp and Paper Technology Times (1985)
Years), pages 49-54, and pages 65-70, etc., describe many examples of color developers, which can be used as color developers used in the present invention. These disclosures are incorporated herein by reference.

The leuco dye and the developer are separately ground into fine particles of several microns or less using a ball mill, an attritor, a sand grinder, or the like separately in an aqueous solution. Pigments, sensitizers,
A coating liquid is prepared by adding a lubricant and other auxiliaries as needed.

Binders used in the leuco dye coating solution include starch, methylcellulose, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide, etc., and inorganic pigments include kaolin, clay, calcium carbonate, finely divided anhydrous silica. And the like, sensitizers include fatty acid amides, aromatic carboxylic esters, fatty acid esters, aromatic ethers, and many other compounds, and a binder, an inorganic pigment, a sensitizer, a lubricant, As the other auxiliaries, various materials already known, for example, various materials described in detail in the above-cited publications can be used.

The types and amounts of the leuco dye, the color developer, the sensitizer, and other various components used in the present invention are determined by the hue required for each heat-sensitive layer, the heat energy sensitivity, and the recording suitability. Usually, 3 to 12 parts by weight of a developer, 0 to 12 parts by weight of a sensitizer, and 1 to 20 parts by weight of an inorganic pigment are used per 1 part by weight of a leuco dye, and a binder is 10 to 25 parts by weight as a solid content. Is used.

The microcapsules containing the decoloring agent used in the present invention can be obtained by dissolving or dispersing a suitable decoloring agent in an organic solvent that is hardly soluble or insoluble in water, and then microcapsulating the resulting solution by interfacial polymerization. Can be The organic solvent used here is selected from triallyl methane, terphenyl compounds, alkylated diphenyl ether, hydrogenated terphenyl, diphenyl ether, and the like, and used alone or as a mixture. In the present invention, in addition to the above organic solvent, ethyl acetate as a low boiling point dissolution aid,
Auxiliary solvents such as isopropyl acetate and butyl acetate may be added.

As the decoloring agent used in the present invention, many compounds are known, and aliphatic amines, amides, piperidines, piperazines, pyridines, imidazoles, imidazolines, morpholines, guanidines , Amidines, polyethers, glycols, and derivatives of these compounds. Specific examples of these include, for example, JP-A-54-13941,
JP-A-55-25306, JP-A-55-27217, JP-A-55-27217
JP-A-152094, JP-A-55-139290, JP-A-55-152
No. 094, JP-A-56-40588, JP-B-50-17867, JP-B-50-17868, JP-B-51-29024,
JP-A-50-18048, JP-A-64-82986, etc., are particularly preferably insoluble or sparingly soluble in water and soluble in the above-mentioned organic solvent, and are preferably decolorizing agents, and furthermore, guanidine compounds and guanidine derivatives And the like are particularly preferred. The decoloring agent only needs to be contained in an amount sufficient to erase the coloring dye, and is in a range of about 50 to 1000% by weight based on the total of the leuco dye and the developer in each recording layer. In practice, the amount can be determined experimentally.

Examples of the wall material of the microcapsules used in the present invention include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, gelatin and the like. If necessary, two or more of these may be used in combination. May be. In the present invention, it is preferable to use microcapsules of polyurethane, polyurea, polyamide, and polyester wall materials among the above-mentioned polymer materials, and further to use microcapsules having polyurethane-polyurea, polyurethane, and polyurea wall materials. Is particularly preferred.

The microcapsules used in the present invention are:
After emulsifying a core material containing a decoloring agent in an aqueous solution of polyvinyl alcohol or the like, forming a wall of the polymer around the emulsified oil droplet, the reactant forming the polymer is formed of an oil droplet. It is added inside and / or outside the oil droplets to polymerize, polycondense, or crosslink to encapsulate. The method of microencapsulation that can be used in the present invention is described, for example, in JP-A-59-222716 or "Microencapsulatio
n) '', edited by JR Nixon, Marcel Decker (M
(Arcel Dekker Inc.), 1976, Chapter 2, the details of which are incorporated herein by reference.

The microcapsules produced as described above are:
When heat is applied, the microcapsules break or the microcapsules penetrate the microcapsule wall without breaking, and the decoloring agent is released to the outside. By using such heat-sensitive microcapsules, the decoloring agent is stably isolated, and even if the decoloring agent is present in or near the leuco dye coloring layer, the coloring function before coloring is achieved.
As a result, a multicolor heat-sensitive recording material which does not impair the stability of color image recording after color development could be obtained.

If necessary, a binder, for example, polyvinyl alcohol, starch,
Add or dilute other auxiliaries such as styrene-butadiene latex and acrylate emulsion to make a coating solution. When the decapsulating agent-encapsulated microcapsules are contained in the leuco dye coloring layer, the obtained microcapsule solution is directly mixed with the previously obtained leuco dye coloring layer coating solution and used. The presence of the decolorizing agent microcapsules in the vicinity of the leuco dye coloring layer is achieved by undercoating or overcoating the leuco dye coloring layer so as to be in direct contact with the front or back surface thereof.

The color forming layer using a sublimable dye used in the multicolor heat-sensitive recording material of the present invention comprises a combination of a layer containing a sublimable dye and a layer containing a thermoplastic resin. Sublimable dyes are rarely colorless and are generally colored. Therefore, it is preferable to introduce white pigment titanium oxide particles into the thermoplastic resin to conceal the hue of the sublimable dye and whiten it. When high heat energy is applied, the sublimable dye sublimates and transfers to the sublimable dye coloring layer containing the thermoplastic resin on the upper side. At this time, the thermoplastic resin contained in the sublimable dye coloring layer is melted and softened, and at the same time, captures and dyes the sublimable dye to form a color.

When a multicolor heat-sensitive recording material is obtained by using only a leuco dye, a color developer, and its decoloring agent, the colors of the respective heat-sensitive coloring layers are mixed, and the color tones are clearly separated. It is extremely difficult to perform this process, and in particular, it has not been possible to obtain a multicolor thermal paper that develops two or more colors. By introducing a sublimable dye coloring layer having a completely different coloring mechanism from that of the leuco dye coloring layer, the present inventors can first separate the color tone sharply and obtain a multicolor heat-sensitive recording material. Was completed.

In the present invention, it is an essential condition to have a sublimable dye color-forming layer, and a multi-layer formed by forming at least one color-forming layer containing a leuco dye, a color developing agent and a decoloring agent thereon. The present invention relates to a thermosensitive color recording material. As is obvious, a thermosensitive recording material that develops two colors when one erasable leuco dye coloring layer is formed, and a thermosensitive recording material that develops three colors when two erasable leuco dye coloring layers are formed. can get.

The sublimable dye used in the present invention is a dye which sublimates or vaporizes at 180 to 250 ° C. The sublimation temperature is preferably 20 to 80 ° C. higher than the highest coloring temperature of the leuco dye. Sublimable dyes that can be specifically used are disperse dyes, thermal transfer recording materials such as oil-soluble dyes, sublimable dyes used for thermal transfer printing, etc., for example, CI Disperse Yellow disclosed in JP-A-63-65029. 1, 3, 8, 9, 1
6, 41, 54, 60, 77, 116, etc .; CI disperse thread
1, 4, 6, 11, 15, 17, 55, 59, 60, 73, 83, etc .; CI Disperse Blue 3, 14, 19, 26, 55, 60, 64, 72, 9
9, 108 etc .; CI Solvent Yellow 77, 116 etc .; CI
Solvent Red 23, 25, 27 etc .; CI Solvent Blue 36, 83, 105 etc. can be used. Naturally, these sublimable dyes can be used alone or as a mixture of two or more of them for adjusting the color tone. It is important that the sublimable dye used here sublimates at a temperature equal to or higher than the color formation temperature of the leuco dye coloring layer, and is further selected from sublimation dyes having an optimum sublimation temperature for applied heat energy.

The sublimable dye layer comprises the above-described sublimable dye as a solvent,
For example, dissolved or finely dispersed in toluene, hexane, methyl ethyl ketone, ethyl acetate, methyl alcohol, ethyl alcohol, and the like, and a binder such as polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, cellulose acetate butyrate, polyamide, polyacrylate, and polystyrene. Alternatively, a coating solution is prepared by using a mixture of two or more of these, and further adding a sensitizer or an inorganic pigment as needed.
Further, it is finely dispersed in an aqueous solution together with an aqueous binder such as polyvinyl alcohol, styrene-butadiene latex, and acrylate emulsion to form a coating solution. As the inorganic pigment used here, those used for the leuco dye coloring layer and the like can be used. Examples of the sensitizer include an aliphatic amide, an aromatic carboxylic acid ester, an aliphatic ester, and an aromatic ether as described in the leuco dye coloring layer.

As the thermoplastic resin used for the sublimable dye fixing layer formed on the sublimable dye layer, any thermoplastic resin dyed with a sublimable dye can be used. From the viewpoint, it is particularly preferable to use a polyester resin. These resins are present in the form of a coating in the layer or in the form of finely dispersed particles. However, from the viewpoint of capturing the sublimable dye, it is particularly advantageous that the surface area is large, and a polyester dispersion finely dispersed in fine particles is preferably used. From the viewpoint of capturing the sublimable dye sublimated from the lower sublimable dye layer, the resin is preferably softened and melted by the heat applied by the thermal head, and a polyester resin having a relatively low molecular weight is particularly preferable. As a preferred example, the sublimation property of the present invention using a dispersion liquid of a polyester resin having a particle diameter of 10 μm or less, more preferably 0.5 to 2.0 μm, and a glass transition temperature of 100 ° C. or less, more preferably 80 to 90 ° C. It is particularly preferable to form a dye fixing layer. Various polyester dispersions are commercially available as polyester resin dispersions suitable for this purpose. For example, there is an aqueous polyester dispersion (trade name: Polyester) manufactured by Nippon Synthetic Chemical Co., Ltd. This aqueous polyester dispersion is a 20% dispersion of a polyester resin having a particle size of about 5 μm and a glass transition temperature of 57 ° C.

The titanium oxide used here simply has to mask the degree of coloring of the sublimable dye, and any commercially available titanium oxide can be generally used without any particular limitation.

If necessary, an inorganic pigment other than titanium oxide may be used in the sublimable dye fixing layer. Examples of such inorganic pigments include inorganic pigments usually used in the field of paper processing, such as clay, talc, silica, magnesium carbonate, alumina, aluminum hydroxide, magnesium hydroxide, kaolin, zinc oxide, calcium carbonate, and aluminum oxide. Etc. can be used. In addition, other auxiliaries, such as sensitizers, used in ordinary thermal papers comprising leuco dyes are also used in the sublimable dye fixing layer according to the purpose. Examples of the sensitizer include the same aliphatic amides, aromatic carboxylate esters, aliphatic esters, and aromatic ethers as described in the leuco dye coloring layer.

The thermoplastic resin of the sublimable dye fixing layer used in the present invention is used in an amount of 2 to 50 parts by weight, preferably 5 to 10 parts by weight, based on 1 part by weight of the sublimable dye. Is 5 to 16 parts by weight per 1 part by weight of the sublimable dye,
It is preferably used in the range of 8 to 10 parts by weight. Titanium oxide and, if necessary, an inorganic pigment as described above, for example, polyvinyl alcohol, styrene-butadiene latex, starch, added to an aqueous solution in which polyacrylamide and the like are dissolved, using an attritor, a ball mill, a sand grinder, or the like. After fine dispersion, an aqueous resin dispersion for fixing a sublimable dye is added to obtain a coating liquid.

As described above, the obtained coating liquids are applied to suitable papers such as base paper, woodfree paper, condenser paper, cellophane, polyethylene film, polyester film, etc. by a coating method using a wire bar, air knife, roll, gravure screen, blade, or the like. Coated on a support. If necessary, water-soluble on the support to prevent the penetration of the coating solution into the support or the sublimation of the sublimable dye,
Alternatively, the undercoat anchor coat layer may be formed using a resin soluble in an organic solvent or an aqueous latex.

The sublimable dye layer is first coated on a suitable support and dried. A white sublimable dye-fixing layer is coated thereon and dried in the same manner. Further, a leuco dye coloring layer containing a decoloring agent microcapsule is applied thereon and dried.
Thus, a two-color heat-sensitive recording material can be obtained. Next, when a three-color heat-sensitive recording material is to be obtained, a second heat-sensitive layer containing a decolorizer capsule having a different color-developing hue is similarly applied thereon and dried. Each coating amount is experimentally determined according to the color density, heat sensitivity, color erasing effect, etc., but a sublimable dye layer: 0.05 to 5 g / m ² , a white sublimable dye fixing layer: 1 to 10 g / m ² m ^2, the leuco dye color-developing layer; 2~12g / m ^2, preferably from 3 to 7 g / m ^2, decolorizer microcapsules containing layer;
It is in the range of ^{2 to} 15 g / m ² .

In order for the decolorizer capsules not to be mixed in the leuco dye coloring layer and for the decolorizer microcapsules to be present in the vicinity thereof, it is necessary to first apply the decolorizer-encapsulated microcapsules after applying the sublimable dye coloring layer. This is achieved by applying a liquid, followed by applying a leuco dye coloring layer free of the decoloring agent microcapsules to form another layer. When two or more colors are formed, the decapsulating agent-encapsulated microcapsules are formed on the leuco dye-developing layer, and then the second leuco dye-developing layer is formed. Or a sandwich.

Further, the component further penetrates between the sublimable dye coloring layer and the leuco dye coloring layer, and / or between two leuco dye coloring layers when two or more leuco dye coloring layers are used. Alternatively, a blocking layer may be formed so as not to mix, or a protective layer may be formed on the surface of the uppermost leuco dye coloring layer.

[0037]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (Example 1) using a wire bar coater to 2-color thermal 55 g / m ² woodfree paper, woodfree paper surface from (I) sublimable dye layer coating amount: 2 g / m ² (II) sublimable dye fixing Layer Coating amount: 4 g / m ² (III) Decolorant microcapsule coating layer Coating amount: 6 g / m ² (IV) Leuco dye coloring coating layer Coating amount: 2 g / m ² By applying the liquids (I) to (IV) having the following compositions, a two-color heat-sensitive recording paper was obtained. (I) Sublimation dye layer coating liquid parts by weight Toluene 400 Methyl ethyl ketone 400 Denka vinyl # 1000AKT (Note 1) 100 Kaya set YELLOW-AG (Note 2) 40 Aerosil # 200 (Note 3) 30 (II) Sublimation dye fixing Layer coating solution weight part aqueous polyester resin (Note 4) 700 Titanium oxide 300 Aerosil # 200 20 (III) Decolorant microcapsule coating solution 20% polyvinyl alcohol solution 200 parts by weight, Hisol SAS-296 (Note 5) After emulsifying a mixed solution of 35 parts by weight, 30 parts by weight of Sumidur N-75S (Note 6), and 10 parts by weight of Succinol-DT (Note 7) to a particle size of 2 to 5 μm using a homomixer or a disper, % Epicure (Note 8) aqueous solution
The composition was heated to 0 ° C. and cured to obtain a decolorizing agent microcapsule coating liquid. (IV) Leuco Dye Color Coating Liquid A liquid and a B liquid having the following compositions were separately prepared and mixed to prepare a leuco dye color coating liquid (red). Solution A parts by weight bisphenol A (Note 9) 300 Calcium carbonate 200 20% aqueous gooselan solution (Note 10) 300 water 400 Solution B parts by weight CVL (Note 11) 100 Calcium carbonate 70 20% Gooselan aqueous solution 100 Water 330

The two-color heat-sensitive recording paper obtained as described above was used as a thermal printer PW-PR01-02 manufactured by NEC Corporation.
And a vivid color image was obtained at output level 2 and blue at output level 5 and yellow at output level 5.

Example 2 Three-color heat-sensitive 55 g / m ^{2 high-} quality paper was coated from the surface of the high-quality paper using a wire bar coating machine. (I) Sublimable dye layer Coating amount: 2 g / m ² (II) Sublimation Coating amount: 4 g / m ² (III) Decolorizer microcapsule coating layer Coating amount: 6 g / m ² (IV) Leuco dye coloring coating layer Coating amount: 2 g / m ² (V ) Decolorant microcapsule coating layer Coating amount: 6 g / m ² (VI) Leuco dye coloring coating layer Coating amount: 2 g / m ² , consisting of the following compositions (I) to (VI) ) The solution was applied to obtain a three-colored heat-sensitive recording paper. (I) Sublimation dye layer coating liquid weight part toluene 400 methyl ethyl ketone 400 Denka vinyl # 1000AKT 100 Kaya set YELLOW-AG 40 Aerosil # 200 30 (II) Sublimation dye fixing layer coating liquid weight part aqueous polyester resin 700 titanium oxide 300 Aerosil # 200 20 (III) Decolorizing agent microcapsule coating solution 20% polyvinyl alcohol solution 200 parts by weight, Hysol SAS-296: 35 parts by weight, Sumidur N-75S: 30 parts by weight, Succinol-DT: 10 After emulsifying the mixed solution of parts by weight to a particle size of 2 to 5 μm using a homomixer or a disper,
A 5% aqueous solution of epicure was added dropwise, and the temperature was raised to 40 ° C. for curing to obtain a coating solution for the decolorizing agent microcapsules. (IV) Leuco Dye Color Coating Liquid (Red) A liquid A and a B liquid having the following compositions were separately prepared and mixed to obtain a leuco dye color coating liquid (red). A part by weight bisphenol A 300 Calcium carbonate 200 20% gooselan aqueous solution 300 water 400 B part by weight vermillion-DCF (Note 12) 100 Calcium carbonate 70 20% gooselan aqueous solution 100 water 330 (V) Decolorant microcapsule coating Liquid (III) Decolorizer Same as microcapsule coating liquid. (VI) Leuco Dye Color Coating Solution (Blue) A C solution and a D solution having the following compositions were separately prepared, and mixed to obtain a leuco dye color coating solution (blue).

The three-color-developed thermal recording paper obtained as described above was used with a thermal printer PW-PR01-02 manufactured by NEC Corporation.
And a vivid color image of blue was obtained at output level 1, red at output level 3, and yellow at output level 5.

(Example 3) 55 g / m ^{2 high-} quality paper was coated from the surface of the high-quality paper using a wire bar coating machine. (I) Sublimable dye layer Coating amount: 2 g / m ² (II) Sublimable dye fixation Layer Coating amount: 4 g / m ² (III) Leuco dye coloring coating layer Coating amount (2 g / m ² ) A two-color heat-sensitive recording paper was obtained. In this example, microcapsules were contained in the heat-sensitive layer. (I) Part by weight of sublimation dye layer coating liquid Toluene 400 Methyl ethyl ketone 400 Denka vinyl # 1000AKT 100 Kaya set YELLOW-AG 40 Aerosil # 200 30 (II) Part by weight of sublimation dye fixing layer coating liquid aqueous polyester resin 700 Titanium oxide 300 Aerosil # 200 20 (III) Leuco dye coloring coating solution A solution, B solution and C solution having the following composition were separately prepared, and then mixed at a ratio of 2: 1: 1 by weight to the leuco dye. A color forming coating solution was used. A part by weight bisphenol A 150 Sensitizer HS-2046 150 Calcium carbonate 200 20% gooselan aqueous solution 300 water 400 B part by weight vermillion-DCF 100 Calcium carbonate 70 20% gooselan aqueous solution 100 water 330 C liquid Decolorant microcapsules A mixed solution of 35 parts by weight of Hisol SAS-296, 30 parts by weight of Sumidur N-75S, and 10 parts by weight of Succinol-DT was mixed with 200 parts by weight of a 20% polyvinyl alcohol solution using a homomixer or a disper to obtain a particle diameter of 2 to 5 μm. After emulsifying into
A 5% aqueous solution of epicure was added dropwise, and the temperature was raised to 40 ° C. for curing to obtain a coating solution for the decolorizing agent microcapsules.

The two-colored heat-sensitive recording paper obtained as described above was used as a thermal printer PW-PR01-02 manufactured by NEC Corporation.
And a vivid color image of red was obtained at output level 2 and yellow at output level 5.

Example 4 55 g / m ^{2 high-} quality paper was coated from the surface of the high-quality paper using a wire bar coating machine. (I) Sublimable dye layer Coating amount: 2 g / m ² (II) Sublimable dye fixation Layer Coating amount: 4 g / m ² (III) Decolorant microcapsule coating layer Coating amount: 6 g / m ² (IV) Leuco dye coloring coating layer (red) Coating amount: 2 g / m ² (V ) Leuco dye coloring coating layer (blue) Coating amount: 2 g / m ² , liquids (I) to (V) having the following composition were applied to obtain a three-color coloring thermal recording paper. Was. According to this embodiment,
Other combinations having different coloring hues were examined. (I) Part by weight of sublimation dye layer coating liquid Toluene 400 Methyl ethyl ketone 400 Denka vinyl # 1000AKT 100 Kaya set BLACK-922 (Note 14) 40 Aerosil # 200 30 (II) Part by weight of sublimation dye fixing layer coating liquid aqueous polyester Resin 700 Titanium oxide 300 Aerosil # 200 20 (III) Decolorant microcapsule coating solution 20% polyvinyl alcohol solution 200 parts by weight, Hisol SAS-296 35 parts by weight, Sumidur N-75S 30 parts by weight, Succinol-DT After emulsifying 10 parts by weight of the mixed solution to a particle size of 2 to 5 μm using a homomixer or a disper,
A 5% aqueous solution of epicure was added dropwise, and the temperature was raised to 40 ° C. for curing to obtain a coating solution for the decolorizing agent microcapsules. (IV) Leuco Dye Color Coating Liquid (Red) A liquid A and a B liquid having the following compositions were separately prepared and mixed to obtain a leuco dye color coating liquid (red). A part by weight bisphenol A 300 Calcium carbonate 200 20% gooselan aqueous solution 300 water 400 B part by weight vermillion-DCF 100 Calcium carbonate 70 20% gooselan aqueous solution 100 water 330 (V) Leuco dye coloring coating liquid (blue) Liquids C and D having the respective compositions were separately prepared and mixed to obtain a leuco dye coloring coating liquid (blue).

(Note 1) Denka vinyl # 1000AKT; a polyvinyl resin having a molecular weight of 60,000 to 75,000 and a glass transition temperature of 65 ° C. manufactured by Denki Kagaku Kogyo Co., Ltd. (Note 2) Kayaset YELLOW-AG; manufactured by Nippon Kayaku Co., Ltd.
Yellow sublimable dye (Note 3) Aerosil # 200; Nippon Aerosil Co., Ltd., fine powdered silica (Note 4) Aqueous polyester resin; Nippon Synthetic Chemical Co., Ltd., Polyester XWR-901 (Molecular weight 29,400, particle size 0.5 to 2 .
(Polyester resin dispersion containing polyester resin particles having 0 μm) (Note 5) Hisol / SAS-296; Nippon Petrochemical Co., Ltd., bicyclic aromatic hydrocarbon (1-phenyl-1-xylylethane) (Note 6) Joule N-75S; Sumitomo Bayer Urethane Co., Ltd., aromatic polyisocyanate (Note 7) Succinol-DT; Sumitomo Chemical Co., Ltd.
Di-o-tolylguanidine (Note 8) Epicure; Yuka Shell Epoxy Co., Ltd., epoxy resin hardener (Note 9) Bisphenol A; Mitsubishi Chemical Corporation (Note 10) Goseilan G-05; Nippon Gohsei Chemical Co., Ltd. 30,000 molecular weight polyvinyl alcohol resin aqueous solution (Note 11) CVL; Yamamoto Kasei Co., Ltd., crystal violet lactone (Note 12) Vermilion-DCF; Hodogaya Chemical Co., Ltd., red leuco dye (Note 13) Sensitizer HS-2046; manufactured by Dainippon Ink and Chemicals, dibenzyl oxalate (Note 14) Kayaset BLACK-922; manufactured by Nippon Kayaku Co., Ltd.
Black sublimable dye

The three-color-developed thermal recording paper obtained as described above was used with a thermal printer PW-PR01-02 manufactured by NEC Corporation.
And a vivid color image was obtained at output level 1, blue at output level 3, purple at output level 3, and black at output level 5.

[0046]

According to the present invention, the thermal recording material obtained by the above-mentioned embodiment is used as a thermal printer PW-PR0 manufactured by NEC Corporation.
Using the device of 1-02, the applied energy is 1-5 high, medium,
The color was changed to low. In Example 1, it was possible to obtain a thermosensitive recording material of two colors capable of clearly separating the color tone into blue and yellow, and in Example 2, a thermosensitive recording material clearly developing three colors of blue, red and yellow. Furthermore, in Example 3, a multicolor heat-sensitive recording material was obtained which clearly developed into two colors of red and yellow, and in Example 4, three colors of blue, purple and yellow.

[Brief description of the drawings]

FIG. 1 is a schematic structural view of one embodiment of a multicolor heat-sensitive recording material of the present invention.

[Explanation of symbols]

 a ... support b ... sublimable dye (high temperature) coloring layer c1 ... (medium temperature) coloring leuco dye coloring layer c2 ... (low temperature) coloring leuco dye coloring layer 1 ... sublimable dye layer 2 ... sublimable dye fixing layer 3, 4 … Microcapsules containing a decoloring agent 10… Multicolor (three colors) thermal recording material

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B41M 5/18 112 5/26 S

Claims (9)

(57) [Claims] 1. A support (a), a sublimable dye coloring layer (b) formed on the support, and at least one leuco dye coloring layer (c) formed on the sublimable dye coloring layer. Wherein the sublimable dye coloring layer (b) comprises a sublimable dye layer and a thermoplastic resin to which the sublimable dye is fixed, and a titanium oxide which conceals the hue of the sublimable dye. And a microcapsule containing a leuco dye coloring layer (c) containing a leuco dye and a color developing agent, and containing a decoloring agent for coloring the leuco dye. The leuco dye coloring layer (c) exists as a separate layer in or near the leuco dye coloring layer, and the color of the leuco dye coloring layer (c) occurs when a temperature lower than the coloring temperature of the sublimable dye coloring layer (b) is applied, and the sublimation occurs. At the temperature at which the coloring layer (b) develops a leuco dye (c)
A multicolor heat-sensitive recording material characterized in that the coloring of the color is erased by the collapse of the decapsulating agent microcapsules. 2. When two leuco dye coloring layers (c) are present, the coloring of one layer (c1) occurs at a lower temperature than the coloring of the other layer (c2), and the other layer (c2) 2. The multicolor heat-sensitive recording material according to claim 1, wherein the c1 layer is decolored at the color development temperature. 3. When there are two leuco dye coloring layers (c), a yellow sublimable dye coloring layer (b) is formed on the support (a), and a red leuco dye coloring layer is formed thereon. (c _r ), a blue leuco dye coloring layer (c _b ) is further formed thereon, and the outermost leuco dye coloring layer (c _b ) develops color at the lowest temperature, and a leuco dye coloring layer (c c _r) is developed with a temperature lower than the coloring temperature of the high b than coloring temperature of c _b, and color is decolored c _b at that temperature, the sublimable dye color-developing layer (b) is developed with the highest temperature 3. The multicolor heat-sensitive recording material according to claim 2, wherein the color-developed portion of the other layer is decolored at that temperature. 4. The wall material of the microcapsule containing the decoloring agent is polyurea, polyurethane, polyurethane-
The multicolor heat-sensitive recording material according to claim 1, which is selected from the group consisting of polyurea. 5. The multicolor heat-sensitive recording material according to claim 1, wherein the sublimable dye fixing layer contains polyester resin particles and titanium oxide particles. 6. The multicolor heat-sensitive recording material according to claim 1, wherein the sublimable dye layer further contains a sensitizer. 7. The multicolor heat-sensitive recording material according to claim 1, wherein the sublimable dye fixing layer further contains a sensitizer. 8. The multicolor heat-sensitive recording material according to claim 1, wherein said decoloring agent is a guanidine compound. 9. The multicolor heat-sensitive recording material according to claim 1, wherein said support is a high-quality paper or a polyester film.