WO2002042088A1

WO2002042088A1 - Multi-color thermal recording media

Info

Publication number: WO2002042088A1
Application number: PCT/JP2001/009994
Authority: WO
Inventors: Yasunori Ishii; Michihiko Sato
Original assignee: Mitsubishi Paper Mills Limited
Priority date: 2000-11-21
Filing date: 2001-11-15
Publication date: 2002-05-30
Also published as: JP2002219870A

Abstract

Multi-color thermal recording media containing at least two types of electron-releasing dye precursors, which usually have no or pale colors and developing different color tones, on a support and having a thermal recording layer containing an electron-accepting compound which ensures the color-development of these electron-releasing dye precursors, wherein 3-di-n-butylamino-6-methyl-7-bromofluoran is used as one of the electron-releasing dye precursor so as to achieve effects of giving vivid color development, high color separation and excellent image preservation.

Description

Description Multicolor thermal recording material Technical field

The present invention relates to a multicolor heat-sensitive recording material that develops different colors depending on the heating conditions. More specifically, the present invention relates to a multicolor heat-sensitive recording material having a clear color tone, excellent color separation of two or more colors, and excellent image storability. Background art

The heat-sensitive recording material is generally provided with a heat-sensitive recording layer having, as a main component, an electron-donating, usually colorless or pale-colored dye precursor and an electron-accepting developer on a support. Heating with a thermal head, a hot pen, a laser beam, etc., allows the dye precursor and the developer to react instantaneously to produce a colored image.

Such a heat-sensitive recording material has the advantages that recording can be obtained with a relatively simple device, maintenance is easy, and there is no generation of noise. Measurement recorders, fax machines, printers, computer terminals It is used in a wide range of fields such as vending machines, labels and ticket vending machines.

On the other hand, in many applications of thermal recording materials, multicolor thermal recording materials capable of developing two or more colors depending on the heating temperature are desired. As a method for realizing such a multicolor thermal recording material,

(1) The coloring temperature is adjusted by changing the melting point, etc., of the compounds constituting the thermosensitive recording component.Only the thermosensitive recording component with a low coloring temperature develops color at low temperature heating, and the thermosensitive recording component with low coloring temperature at high temperature. A method in which a thermosensitive recording component having a higher coloring temperature develops color at the same time to develop a color tone different from that at the time of low-temperature heating;

(2) Include different thermal recording components in separate layers that are laminated, and reduce the thermal recording components contained in the surface layer closer to the heating source at a lower heating temperature. A method in which a thermosensitive recording component contained in a layer more distant from the surface is colored at a higher heating temperature;

Etc. are known. In the method (1) in which the coloring temperature is adjusted by changing the melting point of the compound constituting the heat-sensitive recording component, usable materials are limited, and there is a problem that a balance with other characteristics cannot be sufficiently obtained. In order to contain different thermosensitive coloring components in the same layer, it is necessary to take measures to prevent different types of thermosensitive recording components from interacting with each other to form a color. In addition, the method (2) in which different heat-sensitive recording components are contained in separate laminated layers has a problem that the layer structure of the multicolor heat-sensitive recording material is complicated and productivity is poor.

In order to solve the above-mentioned problems, the compound that constitutes the thermal recording component is encapsulated in a microcapsule and the wall of the microcapsule has a role as a color control layer so that color development such as color temperature can be achieved. Methods for adjusting the characteristics have been proposed. For example, in Japanese Patent Application Laid-Open No. 8-282115, a plurality of electron-donating dye precursors having different coloring colors are contained together with an electron-accepting compound in the same heat-sensitive recording layer. A method has been proposed to enclose at least one of them in a microphone mouth capsule. According to this method, the temperature at which the electron-donating dye precursor contained in the microphone-capsule reacts with the electron-accepting compound to form a color can be increased, and the electron-donating dye contained in the microphone-capsule can be increased. Since the dye precursor and the non-encapsulated electrophilic dye precursor do not interact with each other, two or more types of color tones can be obtained with one heat-sensitive recording layer.

Various microencapsulation methods can be applied as a method of forming a color development control layer on the surface of the compound constituting the heat-sensitive recording component. Must be plastic. As a method of coating the color-forming component with a thermoplastic mic mouth capsule wall, an interfacial polymerization method, a coacervation method, a spray dry method, a curing-in-liquid coating method, a melting dispersion cooling method, and the like are known.

When encapsulating the compound constituting the thermosensitive recording component in a microphone mouth capsule, Since these compounds are usually solids, when using the interfacial polymerization method, the compounds constituting the heat-sensitive recording component are dissolved in a solvent, the raw material for the capsule wall is added, and this is emulsified in a medium such as water. After that, there is a method of evaporating the solvent in which the coloring component is dissolved and polymerizing the capsule membrane, but this method has a drawback that the process becomes complicated and productivity decreases.

In addition, when the coacervation method is used, there are disadvantages that the conditions for producing microcapsules are very limited, and the characteristics of the formed capsule wall are also limited.

When the spray-drying method is used, the uniformity of the capsule film is poor, and the particle size of the capsule tends to increase.

When the in-liquid curing coating method is used, there is a disadvantage that the particle size of the capsule tends to increase.

When the melting dispersion cooling method is used, the melting point of the capsule film is limited to a relatively low melting point, so that there is a disadvantage that the characteristics of the formed capsule wall are also limited.

As described above, by using the conventionally known microphone-mouth encapsulation method, it is impossible to encapsulate the color-forming component in the microphone-mouth capsule with high productivity and to freely adjust the characteristics of the capsule wall of the microphone-mouth capsule.

Japanese Patent Application Laid-Open No. Hei 9-142025 discloses that an electron-donating dye precursor is used as a compound constituting a heat-sensitive recording component, and the electron-donating dye precursor is used as a composite particle with a polyurea or a polyurethane to develop color characteristics. It proposes a method of obtaining a multicolor heat-sensitive recording material by adjusting the particle size and incorporating the composite particles into the heat-sensitive recording material. According to this method, compared to the method using a microphone-mouth capsule, it is stated that the sensitivity is less reduced and that coloring due to pressure or friction is less likely to occur. However, this method requires a large amount of polyurea or polyurethane to completely cover the electron-donating dye precursor, so that sufficient sensitivity cannot be obtained. In addition, there is a disadvantage that the controllability of the coloring properties is also limited to some extent.

In recent years, as the practical use of multicolor heat-sensitive recording materials has been considered, There is a need for a high performance multicolor thermal recording material. Specifically, each color tone is clear and excellent in color separation, and image storability is excellent. Conventionally, to solve these problems, attempts have been made to enhance the color tone and to improve the image preservability. For example, in Japanese Patent Application Laid-Open No. Hei 8-207441, a red-coloring dye precursor selected from 3-ethylamino-17-chlorofluorene and the like as an electron-donating dye precursor, and 1, 1, 3- A method has been proposed in which two or more compounds selected from tris (2-methynole 4-hydroxy-5-cyclohexynolephenyl) butane and the like are used as a preservative improver. It is described that according to the above method, a two-color heat-sensitive recording material having excellent red color development and excellent storage stability of a red color image can be obtained. However, in this method, a clear red color image cannot be obtained because the red color tone is vermilion, and sticking between the thermal paper and the thermal head tends to occur during printing. It was not satisfactory. Disclosure of the invention

The problem to be solved by the present invention is to provide a multicolor heat-sensitive recording material having a clear color tone, excellent color separation of two or more colors, and excellent storage stability of a low-temperature color image.

The present inventors have conducted intensive studies to solve the above problems, and as a result, have come to invent the multicolor heat-sensitive recording material of the present invention.

In the present invention, a heat-sensitive recording layer is provided on a support, and the heat-sensitive recording layer comprises two or more kinds of usually colorless to light-colored electron-donating dye precursors that develop different colors and the electron-donating dye precursors. A multicolor heat-sensitive recording material containing an electron-accepting compound capable of forming a dye, wherein one of the electron-donating dye precursors is 3-di-1-n-butylamino-6-methyl-17-bromofluorane This is a multicolor heat-sensitive recording material characterized in that:

In the multicolor heat-sensitive recording material of the present invention, the electron-accepting compound is a compound represented by the following general formula (I) and a bis (3-aryl-14-hydroxide). Roxyphenyl) Sulfone is preferably at least one selected from the group consisting of sulfones. General formula (I)

[In the formula (I), X represents a hydrogen atom or a lower alkyl group;

R \ R ² and R ³ may be the same or different and each represents a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkyl group, or a cycloalkyl group;

R ⁴ , R ⁵ and R ⁶ may be the same or different and each represent a hydrogen atom, a halogen atom, an alkyl group, or a cycloalkyl group;

R ⁷ is a hydrogen atom or a general formula (II)

(In the formula (II), R ⁴ , R ⁵ and R ⁶ are the same as those in the general formula (I))

Is a group represented by ]

In the multicolor heat-sensitive recording material of the present invention, the compound represented by the general formula (I) is 2,4-bis (phenylsulfol) phenol. Is preferred.

Further, in the multicolor heat-sensitive recording material of the present invention, at least one or more of the electron-donating dye precursors are particles having a color-developing layer obtained by polymerizing a compound having an unsaturated carbon bond on the surface. It preferably exists in the thermosensitive recording layer in a state. BEST MODE FOR CARRYING OUT THE INVENTION

In the multicolor heat-sensitive recording material of the present invention, the heat-sensitive recording layer comprises two or more kinds of usually colorless or light-colored electron-donating dye precursors that form different colors and an electron-accepting colorant that forms the electron-donating dye precursor. And a compound. At low temperature heating, the first color tone is usually formed by a colorless or pale color electron-donating dye precursor and an electron-accepting compound, and at high temperature heating, the first color tone is added to the first color tone. The second color tone is formed by the usually colorless or light-colored electron-donating dye precursor and the electron-accepting compound having a color tone different from that of the above.

In the multicolor heat-sensitive recording material of the present invention, at least one of the two or more usually colorless or light-colored electron-donating dye precursors that develops a different color tone is usually colorless that develops a red color tone. By using 3-di-n-butylamino-16-methyl-7-bromofluoran, which is a light-colored electron-donating dye precursor, a red-colored image with a clear color tone and excellent image storability can be produced at a low temperature. It can be obtained as a colored image. In addition, by using 3-di-n-butylamino-6-methyl-7-bromofluorane as an electron-donating dye precursor, a colorless or pale-colored black-, green-, or blue-based color is developed. However, a high-temperature color image formed by mixing with another electron-donating dye precursor can be made black, which is closer to true black.

Many conventionally known colorless or light-colored electron-donating dye precursors that develop a reddish color tone are known as listed below.

3,3-bis (1-n-butyl-2-methylindole-3-yl) Phthalide, 3,3-bis (1-n-butynole 2-2-methino-lein-done-ole-3-yl) Tetrachlorophthalide, 3,3_bis (1-n-butyl-indone-one-ole-3-inole) Phthalide, 3,3-bis (1-n-pentyl-2-yl-methyl-indole-1-3-yl) Phthalide, 3,3-bis (1-n-hexyl-2-3-methinoleindol-1-3-y Phthalide, 3,3-bis (1-n-octyl-2-methylindole-1-yl) phthalide, 3,3-bis (1-methyl-2-methylindole-3-yl) Phthalide, 3,3-bis (1-ethynoleic 2-methinolein-donore-1-3-inole) phthalide, 3,3-bis (1-propyl-1-2-methylindole-3-yl) phthalide, 3 , 3—bis (2-methylindole-3-yl) phthalide, rhodamine B— Anili noratatam, rhodamine B— (o-chloroanilino) ratatam, rhodamine B— ( _p— nitroa-lino) ratatam, 3-getylamino 5—methyl-7-dibenzylamino fluoran, 3-getinoleamino 6—Methylenol 7—Black mouth fluoran, 3-Jetinoleamino 1-6-Methoxyfluoran, 3-Jetylamino 6-Methylfluoran, 3-Jetylamine 6-Methyl-7-chloro-8—Benzylfluoran, 3-Jetylami NO_6,7-Dimethylfluoran, 3-Jethylamino-6,8-dimethylfluoran, 3-Jetylamino-7-chlorofluorin, 3-Jetylamino NO_7-Methoxyphenoleolan, 3-Jetylamino 7- (N- Acetyl-N-methyl) aminofluoran, 3-getinoleamino-7-methyl Norefholeolean, 3—Jetinoleamino-1 7-Methinoletoxifluorane, 3—Jetinoleamino-7—p—Methylphenyl-Luf / Leolan, 3—Jetylamino-17,8—Venzofluoran, 3—Jetylaminobenzo [ a] Fluoran, 3-methylethylamino [c] Fluoran, 3-dimethylamino 7-methoxyfluoran, 3-dimethyl / reamino-6-methyl-7-chlorofluorin, 3-dimethylamino-7-methyl Fluoran, 3-dimethylamino 7-chlorofluoran, 3- (N-ethyl-ρ-toluidino) _7-methylfluoran, 3- (N-ethyl-N-isoamyl) amino 6-methyl-17- Lorofluoran, 3- (N-ethyl-N-isoamyl) amino-7,8-benzophenolane, 3- (N-ethynole N-isoamyl) Amino-7-methinolefnoreolan, 3- (N-ethylenol N-n-octinole) ) Amino-6-methyl 7-chlorophnoleorane, 3- (N-ethynole N-n-otachinole) Amino-7,8-benzozonorolean, 3- (N-ethynole N-n-octyl) Amino-7-methylfluoran , 3- (N-ethyl-N-n-octynole) amino-1 7-chlorophnoleorane, 3- (N-ethynole-1-N-methylphenyl) amino-1 7,8-benzofluoran, 3- (N-echinole 1-N-4-Methinolepheninole) Amino-7-methinolefluoran, 3- (N-isopentinole-1-N-ethynole) Amino-7,8-benzofunolerane, 3- (N-Etoxyshetyl-N-Ethyl) Amino-1,7,8-Benzophnoleorane, 3- (N-Etoxechinole N-Echinole) Aminnow 7-Black mouth fluoran, 3-n-Dibutinoleamino-6-Methinolay 7-Chromate Mouth Fluoran, 3-n-dibutylamino-7,8-benzofluoran, 3-n-dibutynoleamino-17-chlorophenolean, 3-n-diptinoleamino 7-methylfluoran, 3-diarylamino-7,8 —Benzofluoran, 3-Diallylamino _ 7—Chlorofluorane, 3-Cyclohexylamino 6-Chlorofluorane, 3-Pyrrolidylamino 7-Methylfluoran, 3 —Ethylamino-1-7-Methylfluoran

However, the problem of the present invention cannot be solved using the above-mentioned conventionally known electron-donating dye precursor. For example, among the electron-donating dye precursors described above, a dye precursor that develops a purple-red color tone represented by 3,3-bis (1-ethynoleic 2-methylindole-13-yl) phthalide The body gives a dark color that is far from the original red color, so it is not enough to get a vivid red color. In addition, for example, a dye precursor that develops an orange color, such as represented by 3-getylamino-6,8-dimethylfluoran, has a color tone of black after the color mixture is close to brown. Insufficient. Dye precursors such as 3-Jetylamino-1 7-Mouth Fluoran give a red color from vermilion to orange, so that a clear red color can be obtained. Is insufficient, and the color of black is also close to brown, so not only is the color separation of red and black insufficient, but also the image storability is poor.

On the other hand, 3-di-n-butylamino-16-methyl-7-bromofluoran used in the present invention develops a clear and pure red color tone which cannot be realized by the above-mentioned electron-donating dye precursor, and It is also excellent in preservation of color images. Further, a high-temperature color image, which is usually colorless or light-colored and develops a black-based, green-based, or blue-based color tone by mixing with another electron-donating dye precursor, can be converted to a black color that is almost pure black.

In the present invention, a sufficiently clear red-colored image can be obtained by using 3-di-n-butylamino 6-methyl-7-bromofluorane as a dye precursor that develops a red color tone. Although it is possible to obtain a multicolor heat-sensitive recording material which is excellent in color separation of two colors and excellent in image preservability, the object of the present invention is to further fine-tune the red color tone. As long as the effect is not impaired, it is also possible to use other usually colorless or light-colored electron-donating dye precursors that develop a red color tone. Other dye precursors that develop a red color can be selected from the electron-donating dye precursors listed above.

In the multicolor heat-sensitive recording material of the present invention, among the two or more kinds of the electron-donating dye precursors contained in the heat-sensitive layer, 3-d-n-butylamino 6-methyl-7-bromofur which develops a red color tone. At least one of the dye precursors other than orane is an electron-donating dye precursor that develops a black, green, or blue color tone to obtain a black color tone by mixing with red that develops at low temperatures. Is used. Examples of the dye precursor that develops a black, green, or blue color tone include electron donating compounds generally used in heat-sensitive recording paper and pressure-sensitive recording paper. Specific examples include the following, but are not limited thereto.

Black electron-donating dye precursors: 3-dibutylamino 6-methyl-7-arinofluoran, 3-dibutylamino_6-methyl-7_phenylaminofluoran, 3-dibutylamino 7- (2-chloroamino- Reno) Phenoleorane, 3-dibutinoreaminol 7— (o—black mouth phenyl) amino fluoran, 3-getylamine 6—methyl-7-anilinol fluoran, 3-getylamino 6-methyl-7 phenylaminofluoran, 3-getyl Amino 6-methyl-7-xylidinofluoran, 3-diethylamino 7- (2-chloroanilino) fluoran, 3-getylamino-7- (o-chlorophenyl) aminofluoran, 3-getylamino-7 (o-phenyl phenyl) amino-fluoran, 3-methylamino 7-(2-phenol-phenylamino) fluoran, 3-(N-cyclohexyl N-methyl) amino 6-methyl- 7—Ninyl fluoran, 3— (N-cyclohexyl N-methyl) amino 6-Methinole 7-Hue NOREAMI NOPHNOOLEOLAN, 3- (N-CYCLOPENTYL-N-ETHYL) AMINO-6-METHYL-7-FUE-LAMINO FLUORORAN, 3— (N-ISOAMILOOL N-ETHYL) AMINO-6-METHYL-7-AERI NO FLUORORAN, 3- (N-ethyl-p-toluidino) 1-6-methyl-7-anili-nofluoran, 3- (N-ethyl-P-toluidino) 1-6-methyl-7_ (p-toluidino) fluoran, 3- (N-ethyl-N) Amyl-6-methyl-7-phenylaminofluoran, 3- (N-methyl-N-tetrafluorofurfuryl) Amino-6-methyl-7-furaminofluoran, 3- (N-ethynole N-tetrahi Drofurfuryl) amino-6-methyl-7-phenylaminofluoran, 3-pyrrolidino-6-methyl-7-furaminofluora , 3-Pyrrolidino-6-methyl-7-: ρ-Butylphenylaminophthalenolane, 3-Piperidino 6-Methinole 7-Pheninoleaminophgreorane, 2-Phenylamino-3-methyl-6- (N —Echillu N—p—Tril) Ami Nof Luoran

Green electron donating dye precursor: 3- (N-ethyl-N-n-hexyl) amino-7-anilinofluorane, 3- (N-ethyl-N-p-tolyl) amino-7- (N-furyl N-methyl) aminofluoran, 3- (N-ethyl-N-n-propyl) amino-7-dibenzylaminobu Luoran, 3- (N-ethynole N-n-propynole) Amino-6-chloro-one 7-Dipendinoleaminophnoleolane, 3- (N-ethynole N-4-methylthiophene) amino-7- (N-methyl 1-N-phenyl) aminofluoran, 3 _ (N-ethynoleic 4-methinolephenyl) amino-7-dibenzylaminofluoran, 3- (N-ethyl-4-methylphenyl) amino-6-methyl-7-dibenzylamino Phenolelan, 3- (N-ethyl-4-methylphenyl) amino-6-methyl_7— (N-methyl-1-benzyl) aminofluoran, 3- (N-methyl-N—hexyl) amino 7-anilinofluorane, 3- (N-propyl-N-n-hexyl) amino-1 7-anilinofluoran, 3- (N-ethoxy-N-n-hexyl) amino-7 Akolino Fluo Orchid, 3- (N-n-pentyl-1-N-aryl) amino-6-methyl-17-anilinofluoran, 3- (N-n-pentyl-1-N-aryl) amino-1-7-anilinofluoran, 3-n-dibutylamino-6-chloro-7- (2-chloroa-lino) fluoran, 3-n-dibutylamino-1-6-methyl-7_ (2-chloroa-lino) fluoran, 3-n-dibutylamino 6-Methyl-7- (2-Fluoroarilino) Fluoran, 3_n-Diptyramino 7- (2-Chloroilino) Fluoran, 3-n-Dibutylamino-7- (2-Chlorobenzylaniline) Fluorane, 3,3-bis (4-ethylethylamino-2-ethoxyphenyl) -14-azaphthalide, 3,6-bis (dimethinoleamino) fluorene-9-spiro-3 '-(6- ^; dimethylamino) phthalic Do, three 6-methyl-17-benzylamino-fluoran, 3-methylamino-6-methyl-7-dibenzylaminofluorane, 3-ethylamino-16-methyl-7-n-octylaminofluoran, 3-ethylamino-6-methyl-7 ( N-cyclohexyl N-benzylamino) fluoran, ₃ -methylethyl 6-methyl 7- (2-chloroanilino) fluoran, 3-ethylethylamino 6-methyl-7- (2-trifluoromethyl) Reno) Fluoran, 3—Jethylamine 6—Methyl-7— (3—Trifluoromethylani) Fluoran, 3-Jetylamino 6-Methyl-7- (2-ethoxylanilino) Fluoran, 3-Jetinoleamino-6-methyl-1 7- (4-ethoxylino) Fluoran, 3-Jetylamino-6-chloro-7- ( 2-chloroa-lino) fluoran, 3-ethylethylamino 6-chloro-7-dibenzinoleamino-phnoleoran, 3-ethylinoamino-6-chloro-7, anilinofluoran, 3-ethylethylamino 6 —Ethyletoxy 1-7—Ryinirinofluoran, 3—Jetylamino 7—Anilinofluoran, 3—Jetylamino 1 7—Methylanilinofluoran, 3—Jetylamino 1—7—Dibenzylaminofluoran, 3—Jetylamino 7—n—Octyl Aminofluoran, 3-—Jetylamino-7—: Kuguchi-Linofnoleoran, 3-Jetylua Minnow 7-p-Methylphenylanilinofluoran, 3-Getylamino-7_ (N-cyclohexyl-1-N-benzylamino) fluoran, 3-Getylamino-7- (2-chloroanilino) fluoran, 3-Getylamino-7- ( 3-Trifluora-Lino) Fluoran, 3-Jethylamino-7- (21-Trifluoromethyla-Lino) Fluoran, 3-Jetylamino-1 7-(2-Ethoxylinino) Fluoran, 3-Jetylamino-7-(4-Ethoxy) Nilino) Fluoran, 3-Getylamino-7- (2-Chlorobenzidzoleaelino) Funoreolan, 3-Dimethinoleamino-6-Chloro 1 7-Dibenzylaminofluoran, 3-Dimethinoleamino-6-methyl 1 7—n—Otacetylaminofluoran, 3—Dimethylamine 7—Dibenzylaminov Leoran, 3-dimethinoleamino-1 7-n-otatinoleaminofuronol, 3-dibutylamino-7- (2-fluoroalanilino) fluoran, 3- [p-(: p-alpha-linoleinirino) a-lino]- 6-methyl-1 7-chloro fluoran, 3-anilino 1 7-dibenzylaminofluoran, 3-alpha-lino 6-methinole 7-dipendinole aminofluoran, 3-pyrrolidinol 7-dibenzyla Minofluoran, 3-pyrrolidinol (7-cyclohexyl-lino) fluoran, 3-dibenzylamino-6-methyl-7-dibenzyl / leaminofunolelane, 3-dibenzylamino One 7-dibenzinoleamino phnoleorane, 3-dipenzinoleamino-7- (2-chloroamino) fluoran

Blue-based electron-donating dye precursors: 3- (1-Ethyl-2-methylin-l-3-inole) -1,3- (4-ethylenaminophenyl) phthalide, 3- (1-ethynoley 2-methinolay) 1-3 (Isle) 1 3-(2-Methyl 4-Jetylaminophenol) 1-4-Azaphthalide, 3-(1-Ethyl 2-Methylindole 1-3-Innole) 1 3 — (2-Ethoxy 41-aminophenyl) 4-azaphthalide, 3 _ (1-Ethyl-2-methylindoleno-3-inole) 1-3— (2-Ethoxy-4-methinoleaminophenyl) 1-4 Azaphthalide, 3— (1-Ethyl-1-Methylindole—3-yl) 1-3— (2_Ethoxy-14-Ethylaminoamino) 1-4 Azaphthalide, 3 -— (1-Ethyru) .2—Methylindole 3-yl)-3-(2-ethoxy) _ 4—Dimethylaminophenyl 14-azaphthalide, 3— (1-ethinolay 2-methinoreindolone 1-3-yl) 1-3— (2—ethoxy 4-tetrachloroaminophen) -Le) 4-azaphthalide, 3- (1-ethyl-2-methylindole-3-yl) 1-3- (2-ethoxy-14-dipropylpyraminophenol) -1-azaphthalide, 3- (1-Ethyl-1-2-methinoleindol-3-yl) 1-3- (2-ethoxy-14-dibutylaminophenyl) 1-4-azaphthalide, 3- (1-ethyl-2-methinolein Donoré 3-Inore 1-3-(2-Ethoxy 1-4-diacetylaminofur)-4-azaphthalide, 3-(1-ethyl 2-Methinolein 1-Inore) 1 3-(2 —Ethoxy-1-4-dihexynolefaminophenyl) 4-Azaphthalide 3- (1-ethyl-1-2-methylindole-1-3-yl) -13- (2-ethoxy-1-4dihydroxyaminophenol) -4-azaphthalide, 3- (1-ethyl-1-2-methinolein Dol-1-yl)-3-(2-ethoxy-14-dichloroaminophenyl) -14-azaphthalide, 3- (1-ethyl-2-methylindole-3-yl) 1-3- ( 2-Ethoxy 4-dibromoaminophenol-14-azaphthalide, 3- (1-ethyl-2-methylindole-13-yl) One 3— (2-Ethoxy-1-4 diarylaminophenyl) One 4-azaphthalide, Three— (1-Ethyl-2-Methylindole 1-3-Inole) One 3— (21-Ethoxy_4 (Droxy Amino Feel) 1 41 Azaphthalide,

3- (1-ethyl-2-methylindole-1-3-yl) 1-3- (2-ethoxy4-dimethoxyaminophenyl) 1-4-azaphthalide, 3- (1

—Ethyl-1 2—Methylindole 1 3 _yl) 1 3— (2—ethoxy 4 diethoxyaminophenyl) 1—4 1azaphthalide, 3— (1—ethyl alcohol 1—methinolein Inore) _ 3— (2 ethoxylate 4 hex mouth hexinoleaminofu-nore) — 4azaphthalide, 3— (1 ethino 1 2—methinolein 1 3—3) 1 3— (2 —Ethoxy 4-dimethylethoxyaminophen) — 4-azaphthalide, 3— (1-ethynole — 2-methylindole 3-yl) 1-3 — (2-ethoxy-14-diethyl) Ethoxyaminophenyl) 4-azaphthalide, 3- (1-ethyl-2-methylindole-3-yl) 1-3- (2-ethoxy-14-ethylethylbutoxyaminophenyl) 1-4 1-azaphthalide, 3- (1- 1 3 _ (2-ethoxy 1 4-dimethylcyclohexylamino phenyl) _ 4 1 -azaphthalide, 3-(1-ethyl _ 2-methyl indyl 3-yl) ) One 3— (2—Ethoxy

4-Dimethoxy hexylaminohexyl)-4-azaphthalide, 3- (1-ethyl-2-methylindole-3-yl)-3- (2-ethoxy-4-pyrrolidylaminophenyl) 1) 4-azaphthalide, 3— (1-ethynole _2—methinoreindolone 1-3-inole) _3— (3-ethoxy-14-Jetylaminophenyl) 1-4-azaphthalide, 3— (1-Ethyl — 2-Methynolein-One-Three-Innole) One-Three- (2,3-Diethoxy-1-Ethylaminophenyl) One-Four-azaphthalide, Three- (One-Ethyl-2-Methylindole-One) ) — 3— (4—Jetylaminophenol) — 4—azaphthalide, 3— (1—ethyl-2—methylindole-3-inole) 1 3— (2 chloro-4—jetino) Reaminofile) 1 4-azaphthalide, 3— ( 1-ethyl-2-methylindole-3-yl) 1 3— (3—Black mouth 1—4-Jetinoreami nofu-Nore) 1—4—azaphthalide, 3 _ (1—Ethyl 2—Methylindole 3—yl) 1 3 _ (2—Promo 4—Jet2 1-azaphthalide, 3- (1-ethyl-2-methinolein-donore-1-3-inole) 1-3- (3-promo 4-jetylaminophenyl) 1-4-azaphthalide, 3- (1-ethylethyl) 2—Methino Reindeolone 3—Innole 1 3— (2—Echinorre 41—Jetinole Aminophenol) 1—4-azaphthalide, 3— (1—Ethyru 2—Methyl in Donore 1 3 —Innole) 1 3— (2-propynole 1-4- ethynoleamide) 4- 3-azaphthlide, 3- (1-ethyl-2-methylindole 1-3-inole) 1-3-(3-methynole 4-cetinoleamine) 1- 4-azaphthalide, 3- (1-ethyl-2-methylindole-3-yl) 1-3- (2-etro-4-4-ethylthiaminophenyl) 14-azaphthalide, 3 — (1-ethyl-2-methylindole-3-yl) -3— (2-aryl-1-4-ethylethylaminophenyl) 1-4-azaphthalide, 3-1-1 (1-ethylinoyl 2-methinolein-one-3) —Inore) 1 3— (2—Hydroxy _ 4—Jetylaminophenol) 1-4 Azaphthalide, 3— (1—Ethyru 2—Methylinoreindone 1 3—Isle) 1 3 _ (2—Ciano) 4-Jetylaminofer) _ 4-azaphthalide, 3- (1-ethyl-1-2-methinolein-donore-1-3-inole) 1-3- (2-cyclohexinoleethoxy-1-4-jetylaminophenyl) 1-4-azaphthalide , 3 _ (1 — ェChill 2-Methylindole 1-3-yl) 1-3- (2-Methylethoxy-14-Jetjylaminofuer) _4-I-azaphthalide, 3- (1-Ethynole-1 2-Methylindole-3-yl) ) 1-3-(2-cyclohexylethyl 4-dimethylaminophenyl) 1-4 -azaphthalide, 3-(2-ethylin-roux 3-yl) 1 3-(2 _ ethoxy 4) 4-Jazaphthalide, 4-azapuride, 3- (1-Ethyl-2-chloroindole-3,3-yl) 1-3- (2-Ethoxy-4-jetinoleaminophenyl) 1-4-azaphthalate Lido, 3— (1-Ethyru 2-Bromoindole 1-3-inole) 1-3— (2-Ethoxy 4-Jetylami nofuer)- 4 1-azaphthalide, 3— (1-ethyl 2-, ethyl indole 1— 3-inole) 1— 3— (2-ethoxy 4- 4-ethylinaminoamino) _ 4-azaphthalide, 3— (1-ethyl 2-) —Propylindole—1—3—yl—1—3— (2—Ethoxy—4—Jethylaminophenyl) —14—1azaphthalide, 3— (1—Ethyl-2—Methoxyindole—3—yl) (2-Ethoxy-14-Jethylaminophenol) 1-4-Azaphthalide, 3- (1-Ethyl-2-Ethoxyindole-3-yl) 1-3- (2-Ethoxy-14-Jethyla) Minofenyl) 4-azaphthalide, 3— (1-ethynoleic 2-pheninolein-donore-1-3-inole) 1-3— (2-ethoxy-4—jetylaminophenyl) 1-4-azaphthalide, 3— (11 Ethel 1 2—Methinolein d'Honoré 3— (inole) 1—3 (2—ethoxy 4—Jetylaminophenol) 1—7—azaphthalide, 3— (1—ethyl 2—methylindole 3—yl) 1 3— (2—ethoxy4—Jetylamine) Nofel) 1-4,7-Diazaphthalide, 3- (1-Ethyru 4,5,6,7-Tetrachloro-2, Methinolein Dhole 3-Inole) _3— (2,1-Ethoxy-14-Jet / Reaminophen -Le) 1-4-azaphthalide, 3- (1-ethynorie 412 trough 2-methinolein one-three-three-three) 1-3- (2-ethoxy-4-jetylaminophenyl) 1-4-azaphthalide, 3--( 1-Ethyl 4-Methoxy-1 2-Methylindole-1 3-yl) — 3— (2-Ethoxy 4-Jetylaminoamino) 1-4-Azaphthalide, 3— (1—Ethyl-4-Methylamino _ 2 —Mechi Indole-1-3-yl-1-3- (2-Ethoxy-1-4-Jetylaminophenyl) 1-4-Azaphthalide, 3_ (1-Ethyru 4-Methino-1 2-Methylindole Gray 3-Ile) 1 3- (2-ethoxy-1-41-ethyl / reaminopheninole) 1-4-azaphthalide, 3- (2-methinoreindolone-3-yl) 1-3- (2-ethoxy-14-ethylethylaminophenyl) One 4-azaphthalide, 3— (1—Black mouth one—2-Methinolide, one-one-one, three-inole) One three— (2-Ethoxy 4-—Jetylaminophenyl) One four-azaphthalide, three— (1 —Promo 2—Methino Reindore 1—3-Innole 1 3— (2—Ethoxy) 4-Jetinoreaminophenyl) _ 4-azaphthalide, 3- (1-methyl

_ 2—Methylinoindole 3—Innole 1 3— (2—Ethoxy 1—4 ジェ ethylaminophenyl) 14—1azaphthalide, 3— (1Methyl 1 2—Methylindole 3— 1) 3-(2-ethoxy-4-ethylaminophenyl)-7-azaphthalide, 3-(1-propyl-1-2-methylindole-1-3-yl)-1--(2-ethoxy-1-4-ethyl) Aminofue El) Single ₄ Azafuta Li de, ₃ i _(1-butyl-2 one-methylindole

_ 3-yl) _ 3-(2-ethoxy _ 4-getylaminophenol) 1-4-azaphthalide, 3-(1-butyl-2 _ 1-3-yl) 3- (2_Ethoxy-14-Jetylaminofuenoren) 17-azaphthalide, 3- (1-Pentyl-12-Methylindole-13-yl) -3-(2-Ethoxy-14-Jetjylaminophenyl) 14-azaphthalide, 3- (1-hexyl-2-methylindole-3-yl) 1-3- (2-ethoxy-14-ethylethylaminophenyl) 14-azaphthalide, 3- (1-hexyl-2-methylindole 3 _yl) 1 3 — (2 -ethoxy 1-4-ethylethylaminophenyl) 1 7 -azaphthalide, 3 — (1 -octinole 2 -methinorendol 1 3- Inore) 1 3— (2—Ethoxy 1 4 Jethylaminophenyl) 1-41 Azaf Tallide, 3- (1-octyl-2-methodoleone-deno-le) 1-3- (2-ethoxy-4,1-ethylenaminophenyl) -17-azaphthalide, 3- (1-octyl-2-methylindol) 1-3-yl) _ 3 _ (2-ethoxy-1-4-ethylethylamino) 1-4, 7-diazaphthalide, 3-(1-1-1-2-methinole-1-3-yl) 1 3- (2-ethoxy-1-4-ethylaminophenol) 4-azaphthalide, 3- (1-methoxy-2-methylindo-lu-3-yl) -3-(2-yes) Toxic 4- (Jetylaminophenol) 14-azaphthalide, 3- (1-Ethoxy-12-methylindole-13-inole) 13- (2-Ethoxy-4-ethylinaminophenol) ) One 4—azaphthalide, 3— (one phenol 2—methylindole 3 _ yl) _ 3-(2-ethoxy 4-Jetylaminoamino-1) 4-azakhta Lido, 3— (1—Pentinole 2—Methinolein Donole 1—3-Inole) 1—3— (2—Ethoxy 1—4—Jetylaminophenyl) 1—7_azaphthalide,

3- (1-Heptyl-2-methylindole-3-yl) 1-3- (2-Ethoxy-1-4-Jetylaminophenyl) -1 7-azaphthalide, 3- (1-Nonyl-1-2-methylyl) N-Doll-1 3-yl-1-3 (2-Ethoxy-1)

4-Jetylaminophenyl) 1-7-azaphthalide, 3,3-bis (p-dimethylaminophenyl) -16-dimethylaminophthalide, 3- (4-dimethylamino-2-methylphenyl) 1-3 (4 —Dimethylaminophenyl) 1 6—Dimethylaminophthalide, 3— (1-Ethyru-2-methylindol-3-yl) 1 3— (4—Jethylamino 2—n—Hexyloxyphenyl) 1 4 One azaphthalide

These black, green or blue dye precursors can be used alone or in combination of two or more.

In the multicolor heat-sensitive recording material of the present invention, the electron-accepting compound which forms two or more of usually colorless or light-colored electron-donating dye precursors that form different colors is generally a heat-sensitive recording material or a pressure-sensitive recording material. The acidic substances used in the above are used. Specific examples include the following, but are not limited thereto.

Clay materials such as activated clay, zeolite, bentonite, 4-phenylphenol, 4-t butynolephen, 4-hydroxyacetophenone, 2,2,2-hydroxydiphenyl, 2,2 ' -Methylenebis (4-methyl-6-t-butylphenol), 4,4'-ethylenebis (2-methynolephenone), 1,1-bis (4-hydroxyphenol). 1,1-bis (4-hydroxyphenyl) pentane, 1,1-bis (4-hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl) cyclo Xan, 2,2-bis (4-hydroxydroxyphenolene) propane, 2,2-bis (4-hydroxydroxyphenolene) hexane, 2,2-bis (4-hydroxydroxyphenolene) 1-3 Echinolexane, 2,2-bis (3-chloro-1-4-hydroxyphenol) propane, 1,1-bis (4 1,1-bis- (4-hydroxy-n-propane), 1,1-bis (4-hydroxy) -n-propane, 4,4,1-dihydroxy-dipheninoleatene, 4,4,4- One-sided hexylidenebis (2-isopropinole pinolephenore), 4,4 'dihydroxydiphenylenoresolenone, 2,4' dihydroxydiphenylenoresolenone, 4-hydroxy-4'methynoresife Ninores Norephone, 4-Hydroxy 4, monoisopropoxydiphen Ninores Nolehon, 4-Hydroxy 4, 1, n-Propoxy diphenylenolesone, 4-Hydroxy 1 4 ' , Bis (3-chloro-4-hydroxyphene) snorehon, bis (3-chloro-4 -hydroxyphene) sunoreju , 4, 4, チビスビス 2 チ 2 2 2 2 2 2 2 2 2 2 4 4 4 4 4 4 4 4 4 4 4 4 4 4 1-, 5-Dioxaheptane, 4-methyldihydroxyphthalenolate, 2,2-bis (4-hydroxyphenyl) acetic acid ester, alkyl gallate, salicyl auride, 5-chloro Phenolic compounds such as salicinorea-lide, nopolak-type phenolic resin, modified terpene phenolic resin, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, 4-hydroxy Hydroxybenzoic acid esters such as benzyl hydroxybenzoate and 4-hydroxybenzoic acid benzobenzil, benzoic acid, salicyl 1-hydroxy-2-naphthoic acid, 2-hydroxy-6-naphthoic acid, 3-isopropylsalicylic acid, 3-cyclohexyl / resalicizoleic acid, 5-cyclohexylsalicylic acid, 3,5 —Di-t-butylsalicylic acid, 3,5-di-t-noersalicylic acid, 3,5-didodecylsalicylic acid, 3-methyl-5-t-dodecylsalicylic acid, 3,5-bis (a, a-dimethyl Benzyl) salicylic acid, 3-methyl-15- (α-methylbenzyl) salicylic acid, 4-η-octyloxycarbo-aminoaminosalicylic acid, 4- {2- (4-methoxyphenoxy) ethoxy} salicylic acid, tartaric acid Or organic acids such as oxalic acid, boric acid, formic acid, stearic acid or their zinc, nickel, Metal salts such as lumidium, calcium, etc., urea derivatives such as bis {4- (4-methylphenyl) sulfo-laminoamine, roponylaminophene} methane, thiourea derivatives, etc.

These electron accepting compounds can be used alone or in combination of two or more.

However, in the multicolor heat-sensitive recording material of the present invention, the electron accepting compound that causes the color of the electron-donating dye precursor, 3-di-n-butylamino 6-methyl-7-bromofluoran, to have a sharper color tone. In order to enhance the image stability and the image preservability, it is particularly preferable to use at least one selected from a sulfonyl compound represented by the following general formula (I) and bis (3-arylu-4-hydroxyphenyl) sulfone. I like it. Of course, it is also possible to use two or more selected from the above electron accepting compounds. General formula (I)

[In the formula (I), X represents a hydrogen atom or a lower alkyl group;

R ⁴ , R ⁵ and R ⁶ may be the same or different and each is a hydrogen atom Represents a hydrogen atom, a halogen atom, an alkyl group, or a cycloalkyl group,

R ⁷ is a hydrogen atom or a general formula (II)

Is a group represented by ]

Examples of the sulfol compound represented by the general formula (I) used in the multicolor heat-sensitive recording material of the present invention include compounds disclosed in JP-A-8-269,000. Specific examples include, but are not limited to, the following.

2,4-bis (pheninolenolephonyl) phenol, 2,4-bis (2-methinolephenylsulfoninole) phenol, 2,4-bis (4-methylphenylinolenophonyl) phenol, 2,4 1-bis (4-bromophenolene), phenol, 2,4-bis (4-phenylenolenosulfonyl) phenol, 2,4-bis (2,4-dimethylphenylsulfol) phenol, 2, 4-bis (3,4-dimethylphenylsulfonyl) phenol, 2,4-bis (2,5-dimethylphenylsulfonyl) phenol, 2,4-bis (2,4,6-trimethino) Phenenoles, phenol, 2,4-bis (4-ethynolepheninoles phenol), phenol, 2,4-bis (4-isopropylphenylsulfonyl) phenol,2,4-bis (4-cyclohexylphenylsulfonyl) phenol

2,4-bis (pheninoresnolephonyl) -1-5-methylphenol, 2,4-bis (2-methylphenylenosulfonyl) -1,5-methinolephenol, 2,4-bis (4-methylphenylene) Enylsulfonyl) 1-5-methylphenolenole, 2,4-bis (4-isopropinolefe-noresnorehenore) 1-5-methinoolephenore, 2,4-bis (2,4-dimethinolephenorelesnolejo) Ninore) One 5-methinolephenore, 2,4-bis (2,5-dimethinolepheninoles rufonyl) One 5-methinolephenone-leone, 2,4-bis (phenylenolenorenole) _ 5-ethylethylenol, 2,4-bis (4-methylphenylsulphonyl) 1-5-ethynolephenore, 2,4-bis (4-ethynolephenenole snorehonore) 1-5-ethynolephenole, 2,4-bis ( 2,4-Dimethino phenol-Lusnolehoninole) 1-5-Echilfenenole, 2,4_bis (2,5 dimethinolephenenolesnolehoninole) 1 5-Echinolenophenol, 2,4— Bis (Huenoresnolehoninore) 1 5-isopropinolephenol

2-(4-Methinolephenolenoleshonole) 1 4- (Phenenolesorenorenole) Phenoenole, 2-(4_ethylphenylsenolehonole)-4- (phenylsulfol-phenol) phenol , 2- (4-Isopropynolephenylsulfonol) 1-41- (Huenoreth / Lehoninole) Pheno / L, 2- (2,5-Dimethinolephenylsnorehonole)-4- (Ninole) phenol, 2- (2,4-dimethylphenylenolesphenol) 1-41 (phenylsulfol) phenol, 2- (3,4-dimethylphenylsulfonyl) 1-41 ( Huenole / Lehoninore) Huenore, 2— (4 口口口口口) 4 一 — エノーノーノーノーノーノーノーノーノーノーノーノーノーNino Re) phenol

2-(Hue-Noresnolehoninole)-4-(4-Methinolehuegresnorehonizole) Phenols, 2-(Hue-Noresnorehoninole)-4-1 ) Phenoenole, 2— (4-propylphenylsulfonol) phenol, 2- (phenylsulfonolole) 1-41 (2-methylphenylsulfonol) phenol, 2— (Fuenoresnolehoninole) 1 4 _ (2,5-Dimethinolepheninoresnorehoninole) Phenols, 2— (Fuelsulfonyl) 1-4— (2,4-Dimethylphenynoresolenoyl) Phenols, 2- (phenylsulfonyl)-4-(3,4-dimethylphenylsulfonel) phenol, 2- (phenylsulfonol) 1 4 1 Les, 2 - (full Ennis less Honoré Honi Honoré) Single 4 one (4 one-bromo Hue Nino less Honoré Honi Honoré) Fueno Le

2- (4-Methynolephenol-sulfoninole) 1-4- (Phenynoles-norhenol) -1-5-Methynolephenol, 2- (4-phenylenolenes-norhenol) 1-4-1 (Phenylsulfonyl) _5- Methylphenol, 2- (4-bromophenylsnorrenole) 1-41 (phenylenolesnorenole) 1-5-methinolephenore, 2- (phenylsenole-norre) 1-4-1 (4-methylenolesnorenole) -Le) — 5-Methylphenol, 2- (phenylsulfonyl) ー 4-1 (4-chlorophenolenes) _ 5 —methylenophenole, 2-(phenylenoles) 4-1- (4-promofenenolesnorenole) 1-5-Methylphenol, 2- (4-methylphenylsnolehoninole) 1-44- (Feninolesurenolinole) 1-5—Echinorenopheno Nore, 2— (4, 1-Mouth Hue-Nore Snorrehoninole) — 4— (Feninolenosrehoninole) —5—Echinorenofuenorenore, 2— (4, 1-bromophenylsnorehonyl)-4-(Fue -Rusulfonyl) 1-5-Ethyl phenol, 2-(Phenylsulfonyl)-1-4-(4-Methylenopheninolenoleshoninole) 1-5-Ethylphenoleno, 2-(Huenoles norenoninole) 1-41 (4-1 mouth mouth feninole reno honore) 1-5-ノレレスレスノノ--4 4 4 4 ブロモ 4 エフ — 5-チフレスノ、、 5 -Methynolephenylsulfonol) 1-41 (Phenylsulfol) -1 5-Isopropylphenol, 21 (Phenylsulfoel) _4-1 (4_Methylphenylsulfonyl) 1-5_Isopropino Refeno

4,4,1-dihydroxy-5- (pheninoles / lehoninole) dipheninoles-norrehon, 4,4 'jihidroxy-1,5,5'-bis (phenenoresnorefoni-nor) dipheninoles-norrejon, 4,4' jihydroxy 1 5— (4-Methinolephenolenohonore) Dipheninolesnorrehon, 4, 4 'Jihidroxy 5,5'-(4-Methinolephenorenesorehonore) Diphenenoresnoreonhon, 4, 4,1'-hydroxy-5,5'-bis (4-one-mouth pheninolenos-renorinole) dihue-noresnorefon, 4,4'-dihydroxy-5-, 5-, 1-bis (4-bromo-enouresnorreno) Ninore) Gifueninores Norehon etc. These sulfone compounds can be used alone or in combination of two or more.

Among the sulfonyl compounds represented by the general formula (I) used in the present invention, when 2,4-bis (phenylsulfonyl) phenol is used, compared with the case where other sulfonyl compounds are used, Basic characteristics such as thermal responsiveness, saturation density of the color image, whiteness of the background, preservation of the image and background, and the amount of residue deposited on the thermal head of the thermal printer are all good. A multicolor heat-sensitive recording material having good and good quality balance without defects can be obtained.

The amount of at least one compound selected from the sulfonyl compound represented by the general formula (I) and bis (3-aryl-4-hydroxyphenyl) sulfone is 3-di-n-butylamino-6. The amount is preferably 50 to 100 parts by weight, more preferably 100 to 600 parts by weight, based on 100 parts by weight of methyl-7-bromofluoran. In addition to the above-mentioned essential electron-accepting compound, it is also possible to add an electron-accepting compound which is generally used for a thermosensitive recording material or a pressure-sensitive recording material.

The heat-sensitive recording layer in the multicolor heat-sensitive recording material of the present invention is, for example, a black color by mixing a low-temperature color image with red and a high-temperature color image with a low-temperature color image and a color tone different from red. In order to obtain a near black color, two color-forming layers are provided on the support, and a color tone of red is formed on the upper layer on the atmosphere side. It is preferable to contain -methyl-17-bromofluorane, and to contain, in the lower layer on the side of the support, a generally colorless or light-colored electron-donating dye precursor which develops a color tone different from red.

Further, the heat-sensitive recording layer in the multicolor heat-sensitive recording material of the present invention may be composed of only one color-forming layer. In this case, the colorless or pale-color electron-donating dye precursor which develops a red color tone at low temperature is used. It develops a color tone different from red, whose thermal response has been adjusted by providing a 3-di-n-butylamino 6-methyl-7-bromofluorane and a color-regulating layer on the surface. The colorless or pale-colored electron-donating dye precursor is usually contained in the same color-forming layer.

In the present invention, by forming the heat-sensitive recording layer with one color-forming layer, the productivity of the multicolor heat-sensitive recording material can be improved, which is more preferable. In this case, a colorless or light-colored electron-donating dye precursor that develops a color tone different from that of the low-temperature color-developed image is polymerized with a compound having an unsaturated carbon bond on the surface, and the color-controlling layer is provided on the particles. It is most preferable to include it in the heat-sensitive recording layer (color-forming layer) in the form because the color tone is clearer and the two-color separation is excellent.

By using the above method, at a low temperature heating, the first color tone is generated by the reaction between the usually colorless or light-colored electron-donating dye precursor having no color-developing layer on its surface and the electron-accepting compound, Heating at a high temperature causes the first color tone to be mixed with the color tone due to the reaction between the usually colorless or light-colored electron-donating dye precursor provided with a color-regulating layer on the surface and the electron-accepting compound. A second tone occurs.

By providing a color-developing layer on the surface of the dye precursor particles, it is possible to adjust the color-developing characteristics so that the color-forming temperature is increased or the color-forming sensitivity is reduced. Conventionally, sensitizers and the like have been added for the purpose of adjusting the color-forming properties to lower the color-forming temperature or to improve the color-forming sensitivity.However, conversely, the color-forming temperature is increased or the color is formed. It was difficult to adjust the coloring characteristics so that the sensitivity was low. The electron-donating dye precursor particles having a color control layer on the surface used in the multicolor heat-sensitive recording material of the present invention, wherein the color control layer is obtained by polymerizing an unsaturated carbon bond-containing compound. By polymerizing the unsaturated carbon bond-containing compound, the productivity is better than when a color control layer is prepared using a conventional microcapsule manufacturing method, and the characteristics of the color control layer are improved. It can be controlled freely.

The color control layer is formed by adding an unsaturated carbon bond-containing compound to the dispersion of the dye precursor particles, adding a polymerization initiator, and then heating as necessary to allow the unsaturated carbon bond-containing compound to undergo addition polymerization. Dye precursor particle surface coated with polymer It is formed by doing.

When the unsaturated carbon bond-containing compound is added to the dispersion of the dye precursor, (a) the unsaturated carbon bond-containing compound is emulsified in the dispersion of the dye precursor, and (b) the dye precursor is dispersed. The liquid dispersion and the majority of the unsaturated carbon bond-containing compound are phase-separated to form separate layers, but a trace amount of the unsaturated carbon bond-containing compound is dissolved in the dye precursor dispersion. And (c) a state in which the dispersion of the dye precursor and the unsaturated carbon bond-containing compound are completely insoluble and completely phase-separated.

Among these states, state (b) force is particularly preferably used for forming a color control layer on the surface of the particles of the dye precursor. That is, when the unsaturated carbon bond-containing compound is polymerized in such a state (b), the surface of the dye precursor particles is more uniform and denser than when polymerized in the other states (a) and (c). This makes it possible to form a color control layer excellent in various properties, and has an advantage that the particles of the dye precursor are aggregated and coarse particles are hardly formed.

State (b) can be realized by appropriately selecting the type of dispersion medium for dispersing the dye precursor particles and the type of unsaturated carbon bond-containing compound.

In addition, in the state (c), it is difficult to form a color control layer on the surface of the dye precursor particles, which is not preferable.

Known polymerization initiators can be used for polymerizing the unsaturated carbon bond-containing compound.The polymerization reaction is not particularly limited in the type of polymerization, such as radical polymerization, anionic polymerization, and cationic polymerization. It is particularly preferably used. Specific examples of the polymerization initiator for radical polymerization are shown below. Peroxides such as tamenodiperoxide, t-butinoleperoxide, dicumylperoxide, di-t-butylperoxide, benzoyl peroxide, lauroyl peroxide, etc., and persulfates such as potassium persulfate and ammonium persulfate. Azo compounds such as azobisisobutyronitrile, a combination of hydrogen peroxide and ferrous salt, a combination of persulfate and sodium acid sulfite, a combination of tamene hydroxyperoxide and ferrous salt Combination, over Combination of benzoyl oxide and getylaurine, combination of peroxide and metal alkyl, combination of oxygen and organometallic alkyl, etc.

The dispersion of the dye precursor and the unsaturated carbon bond-containing compound are substantially insoluble, and most of the dye precursor dispersion and the unsaturated carbon bond-containing compound undergo phase separation to form separate layers. However, when a very small amount of the unsaturated carbon bond-containing compound is dissolved in the dispersion liquid of the dye precursor and a color control layer is formed on the surface of the particles of the dye precursor, a polymerization initiator is used. Particularly preferred is one which dissolves in a dispersion medium in which a dye precursor is dispersed. By using such a polymerization initiator, it is possible to prevent the particles of the dye precursor from aggregating to form coarse particles.

The unsaturated carbon bond-containing compound used to form the color control layer is a compound having a carbon-carbon double bond and a carbon or carbon-carbon triple bond as an unsaturated carbon bond. -Ridene compounds, bielene compounds, cyclic olefins and acetylene compounds.

Specific examples of the vinyl compound, vinylidene compound, vinylene compound, and cyclic olefin include styrene, isobutene, 3-methyl-1-butene, butynolebininoleether, methinolevinyl ketone, nitroethylene, vinylidene cyanide, ethylene, propylene, and vinyl chloride. , Biel acetate, acrolein, methinorea crolein, atalinolea amide, N-methylonyl acrylamide, N-octadecyl acrylamide, N, N-dimethyl acrylamide, α; -ethyl acetyl acrylate, α-cloactyl Ethyl acrylate, methyl methyl acrylate, α-methyl cyanoacrylate, α-phenylmethyl acrylate, benzyl acrylate, butyl acrylate, ethyl acrylate, ferrocenyl methyl acrylate , Glycidyl acrylate, heptafluorobutyl acrylate, methyl acrylate, octadecyl acrylate, octyl acrylate, methyl trifluoroacrylate, 2-chloroethyl acrylate, 2-chloroethyl acrylate Ethylhexyl, 2-acrylic acid 2-nitrobutyl, acrylic acid, mono-promoacrylic acid, Tarylonitrile, allylic acetic acid, acrylyl acrylate, allylic alcohol, arynobenzene, N-arynorestearinoleamide, butadiene, butadiene 1-ethyl olevonate, butadiene 1,1,4-dicanolevonate, 1-butene, 2-butene, N-biel force prolatatam, N-bul canolebamine ethinolate, N-vinyl carbazole, crotone aldehyde, crotonic acid, diaryl melamine, diaryl phthalate, N, N-dibutyl aniline, 1, 1-Dipheninoleethylene, Tetraph / Leo-ethylene, Jethinole-Fumanolate, Tetraclo-hexatriene, 1-Hexene, 1-Vinylimidazole, 1-Vinyl-2-methylimidazole, Indene, Isoprene, Getinole maleate, maleic anhydride, male Mido, methacrylamide, benzyl methacrylate, butyl methacrylate, ethyl methacrylate, ferrocenylmethyl methacrylate, glycidyl methacrylate, isoptyl methacrylate, isopropyl methacrylate, methyl methacrylate, phenyl methacrylate 2-hydroxyhexyl methacrylate, 2-hydroxypropyl methacrylate, methacrylic acid, methacrylonitrile, methacryloylacetone, 2-isopropenyl-2-oxazole, 2-bierquinoline, α- Methynostyrene, α-methoxystyrene, m-butyl styrene, m-chlorostyrene, o-bromostyrene, o-chlorostyrene, p-bromostyrene, p-chlorostyrene, p-methylstyrene, p-methoxy Styrene, Biel benzoate, Biel Decyl ether, divininole ether, vinylethyl sulfoxide, bul formate, bininoleisobutynoleetesole, vinole laurate, vinolefe / leetene ole, ethylene glycolone resin methacrylate, divininolebenzene, livie Examples include, but are not limited to, norenaphthalene, diethyleneglyconoresiary tallate, trimethylolone propane triatalylate, trimethylolpropane trimethatalylate, acrylyl methacrylate, and 1,3-butanediol dimethacrylate. Not something.

Specific examples of the acetylene compound include, but are not limited to, acetylene and phenylacetylene. These vinyl compounds, vinylidene compounds, vinylene compounds, cyclic olefins, acetylene compounds and the like can be used alone or as a mixture of two or more.

It is preferable that the unsaturated carbon bond-containing compound is appropriately selected for the purpose of adjusting the properties of the color control layer. By selecting an unsaturated carbon bond-containing compound, the thermal properties of the dye precursor during heating can be controlled. As a method for controlling the thermal properties of the dye precursor, a compound containing two or more unsaturated carbon bonds in one molecule as an unsaturated carbon bond-containing compound is used, and the amount of the compound is adjusted. And the like.

The ratio of the unsaturated carbon bond-containing compound to the dye precursor is preferably 5 to 500% by weight. When the proportion of the unsaturated carbon bond-containing compound is less than 5% by weight, the function as a color control layer is insufficient, while when it exceeds 500% by weight, the color of the dye precursor is insufficient.

The dispersion of the dye precursor and the electron-accepting compound can be obtained by a method in which the dye precursor is dry-milled and dispersed in a dispersion medium, or a method in which the dye precursor is mixed in a dispersion medium and wet-milled. An arbitrary method can be used as a method for pulverizing. The particle size of the dye precursor particles in the dispersion is preferably 20 zm or less. If the particle size is larger than this, it is not preferable because uniform printing cannot be performed. The particle size is particularly preferably 10 μm or less, and more uniform printing can be obtained. The lower limit of the particle size of the dye precursor particles is not particularly limited, but is preferably 0.1 μιη or more from the viewpoint of easy production.

Among the electron-donating dye precursors used in the present invention, the electron-donating dye precursor used for forming a color-adjusting layer on the surface and obtaining a second color image at a higher temperature includes low-temperature coloring. A compound that develops a black, green, or blue color tone that can produce a black color tone by mixing with a certain red color.Generally, compounds used for heat-sensitive recording paper and pressure-sensitive recording paper must be used. Can be. Specific examples thereof include the above-described electrochromic dye precursors that develop black, green, and blue colors, but the present invention is not limited thereto. These may be used alone or in combination of two or more. Can be.

In the multicolor heat-sensitive recording material of the present invention, a pigment, a sensitizer, an antioxidant, an anti-sticking agent and the like are added to the heat-sensitive recording layer as needed. Specific examples of binders include starches, hydroxyethyl cellulose, methylcellulose, ethylcellulose, canoleoxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, and polyacrylic acid. Methacrylic acid, polyacrylate, polymethacrylate, sodium polyacrylate, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether, aryl resin, furan resin, ketone resin, oxybenzoyl Polyester, Polyacetal, Polyethenoleetherketone, Polyethersnolephone, Polyimide, Polyamide, Polyamidoimid, Polyaminobismaleimide, Polymethinolepentene, Polyphenylene oxide, Reference: phenylene sulfide, polyphenylene sulfone, polysulfone, polyarylate, polyallyl sulfone, polybutadiene, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl urethane, phenolic resin,ゥ Rare resin, melamine resin, melamine formalin resin, benzoguanamine resin, bismaleimide triazine resin, alkyd resin, amino resin, epoxy resin, unsaturated polyester resin, styrene Z butadiene copolymer, acrylonitrile Z butadiene copolymer Polymer, methyl acrylate // butadiene copolymer, ethylene / vinyl acetate copolymer, acrylamide / acrylic ester copolymer, amide acrylic acid Lylic acid ester methacrylic acid terpolymer, alkali salt of styrene Z maleic anhydride copolymer, alkali or ammonium salt of ethylene / anhydrous maleic acid copolymer, and other various polyolefin resins. These can be used alone or in combination of two or more.

As the sensitizer that can be used in the present invention, a heat-fusible substance having a melting point of 60 ° C. to 180 ° C. is preferable, and particularly, a temperature range of 80 ° C. to 1 = 0 ° C. Heatable with melting point A fusible material is more preferred. Specific examples include stearic acid amide, N-hydroxymethylstearic acid amide, N-stearylstearic acid amide, ethylenebisstearic acid amide, oleic acid amide, and palmitic acid amide. And fatty acid amides such as methylenebis hydrogenated tallow fatty acid amide and ricinoleic acid amide, paraffin wax, microcrystalline tusta, polyethylene wax, carnauba wax, etc., and natural waxes, N-stearyl urea, etc. Aliphatic urea compound, 2-benzinoleoxynaphthalene, bis (4-methoxypheninole) ether, 2,2,1-bis (4-methoxyphenoxy) ethynoleether, 1,2-bis (3 —Methyl ^^ phenoxy) ethane, 1,2-bis (phenoxymethyl) benzene, trinolebi Ether compounds such as phenylene ether, naphthino ether derivatives, anthryl ether derivatives, aliphatic ethers, diphenyl adipate, di (4-methylbenzyl) oxalate, di-benzinole oxalate, di-ammonate (4-chloronore) Benzenole) Estenole, diphen-oleate carbonate, dimethinole terephthalenolate, dibenzi / terephthalenolate, fenenoleestenole benzenesnolephonate, ethenorele compounds such as 4-acetinoleacetophenone, m-terphenyl, 4-benzylbiene Biphenyl derivatives such as fuel, 41-acetylbiphenyl and 4-aryloxybiphenyl, bis (4-aryloxyphenyl) sulfone, acetate acetate, 4-methylacetanilide, fatty acid Known heat-fusible compounds, such as aldehydes, may be mentioned. Not limited to, et al., Also can be used alone, or two or more as necessary.

These sensitizers are preferably used in an amount of 20 to 250% by weight based on the dye precursor in order to obtain a sufficient thermal response.

In the heat-sensitive recording material of the present invention, the support on which the heat-sensitive recording layer is provided may be any of transparent, translucent, and opaque paper, nonwoven fabric, woven fabric, synthetic resin film, synthetic resin laminate paper, Paper, metal foil, ceramic paper, glass plate, or the like, or a composite sheet combining these can be used arbitrarily according to the purpose, but is not limited thereto. In the multicolor heat-sensitive recording material of the present invention, one or more protective layers may be provided on the heat-sensitive recording layer directly or via another layer. The components of the protective layer are not particularly limited, but those having little effect on the coloring properties of the heat-sensitive recording composition are particularly preferably used.

Specific examples of the resin used for forming the protective layer include starches, hydrated kissinenoresenorelose, methinoresenololose, etinoresenorelose, carboxymethinoresenorelose, gelatin, and casein. , Polyvinylinoleanol, modified polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyacrylic acid ester, polymethacrylic acid ester, sodium polyacrylic acid, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether , Aryl resin, furan resin, ketone resin, oxybenzoinolepolyester, polyacetanol, polyetherenoate / leketone, polyethersulfone, polyimide, polyimide, polyamide imide, polyamino bis imide, poly Methylpentene, polyphenylene oxide, polyphenylene phenol, polyphenylene phenol, polyphenylene phenol, polyphenylene phenol, polyarylen sulfone, polybutadiene, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride Polyurethane acetate, polyurethane, phenolic resin, urea resin, melamin resin, melamin formalin resin, benzoguanamine resin, bismaleididotriazine resin, alkyd resin, amino resin, epoxy resin, unsaturated polyester resin, Styrene nobutagen copolymer, Atari mouth-tolyl / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / butyl acetate copolymer, acrylic acid amide / atari Acid ester copolymer, acrylamide / acrylic acid ester / methacrylic acid terpolymer, styrene / maleic anhydride copolymer, ethylene / maleic anhydride copolymer Examples thereof include resalts or ammonium salts, and various other polyolefin resins. These can be used alone or in combination of two or more.

In the multicolor heat-sensitive recording material of the present invention, between the heat-sensitive recording layer and the support, An intermediate layer may be provided to improve smoothness, heat insulation and the like. The intermediate layer can contain various resins, organic pigments, inorganic pigments, various hollow particles, and the like.

In the multicolor heat-sensitive recording material of the present invention, the layer between the heat-sensitive recording layer and the support, and the surface on which the Z or heat-sensitive recording layer is provided or on the opposite surface, a layer containing an ink jet-recordable material, It is also possible to provide a layer that eats a material capable of recording information electrically, magnetically or optically. In addition, a back coat layer may be provided on the surface opposite to the surface on which the heat-sensitive recording layer is provided for the purpose of preventing curling and electrification, and may be subjected to adhesive processing or the like. Further, printing with UV ink or the like may be performed on the surface of the heat-sensitive recording layer or the protective layer.

Further, in the multicolor heat-sensitive recording material of the present invention, in order to perform printing with laser light, any layer and support in the heat-sensitive recording material may contain a light-heat conversion material.

In any layer of the multicolor heat-sensitive recording material of the present invention, if necessary, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, hydroxide Inorganic and organic pigments such as aluminum and urea-formalin resin, as well as higher fatty acid metal salts such as zinc stearate and calcium stearate, paraffin, oxidized paraffin, polyethylene, polyethylene oxide, stearic acid amide, caster wax, etc. These waxes may also contain a dispersant such as sodium octyl sulfosuccinate, and a surfactant and a fluorescent dye.

Further, an antioxidant and an ultraviolet absorber can be added for the purpose of improving light resistance. Examples of the antioxidant include, but are not particularly limited to, hindered amine antioxidants, hindered phenol antioxidants, and sulfide antioxidants. Examples of UV absorbers include organic UV absorbers such as benzotriazole UV absorbers, salicylic acid UV absorbers, benzophenone UV absorbers, and the like. Examples include inorganic ultraviolet absorbers such as lead, titanium oxide, and cerium oxide, but are not particularly limited.

【Example】

Hereinafter, the present invention will be described in more detail with reference to Examples. In addition, “part” represents part by weight, and “%” represents% by weight.

Production Example 1 Production of coated paper

Baking power Olin 100 parts, 50% styrene-butadiene-based latettus water dispersion 24 parts, water 200 parts of coating solution, solid content on fine paper of 50 g / m2 basis weight Coating paper was prepared by coating and drying to give a coating amount of 9 g / m2.

Preparation Example 2 Preparation of dispersions of dye precursor, electron accepting compound and sensitizer

The following compositions were individually pulverized using a ball mill so that the volume average particle diameter became 1.0 / im, to prepare Liquids A to G.

Solution A Red coloring dye precursor dispersion

3-di-n-butylamino 6-methyl-7

Promo Honore Sai Run 3

7% 2% polybutyl alcohol aqueous solution

Solution B Red dye precursor dispersion

3-Jetinole amino-7-clo mouth fluoran 3 parts

2% polyvinyl alcohol aqueous solution 7 parts

Liquid C Black dye precursor dispersion

3-1-ethylamino 6-methyl-7- (3-tri

Fluoromethylanilino) Fluoran 3 parts

7% 2% polyvinyl alcohol aqueous solution Solution D Electron-accepting compound dispersion

2,2-bis (4-hydroxyphenyl) propane 3 parts

7% 2% polybutyl alcohol aqueous solution Έ Electron acceptor compound dispersion

Bis (3-aryl-1-hydroxypropyl) sulfone 3 parts

2% poly, bull alcohol aqueous solution 7 parts

Solution F Electron-accepting compound dispersion

2, 4-bis (phenilsnorehoenore) fuenoren 3 parts

7% 2% polybutyl alcohol aqueous solution

Solution G Sensitizer dispersion

2-Benzinoleoxynaphthalene 3 parts

7% 2% aqueous polybutyl alcohol solution Example 1

Preparation of two-layer type multicolor thermosensitive recording material

10 parts of liquid C obtained in Preparation Example 2, 10 parts of liquid D, 100 parts of a polybutyl alcohol 10% aqueous solution as a binder 100 parts of calcium carbonate (manufactured by Shiraishi Industry Co., Ltd.) 30% dispersion as a pigment 50 parts were mixed to prepare a high-temperature color coating solution. Also, 10 parts of solution A, 30 parts of solution D, 100 parts of solution G obtained in Preparation Example 2, 100 parts of a 100% aqueous solution of polyvinyl alcohol as a binder, and calcium carbonate (Shiroishi 50 parts of a 30% dispersion was mixed to obtain a low-temperature coloring coating solution.

Subsequently, 4 gm 2 (dry) was applied to the coated paper obtained in Preparation Example 1 and dried at 60 ° C. to form a black colored layer. Then, 4 g Zm ² (dry) was coated with a low-temperature coloring coating solution and dried in an oven at 60 ° C. to form a red coloring layer. Thereafter, a force-rendering treatment was performed so that the Beck smoothness of the coated surface was 400 to 500 seconds, to produce a multicolor heat-sensitive recording material having two heat-sensitive recording layers.

Example 2

Preparation of two-layer type multicolor thermosensitive recording material

In the same manner as in Example 1 except that 10 parts of E liquid was used instead of 10 parts of D liquid in the high-temperature coloring coating liquid, and 30 parts of E liquid was used instead of 30 parts of D liquid in the low-temperature coloring coating liquid, A multicolor heat-sensitive recording material in which the heat-sensitive recording layer was composed of two coloring layers was prepared.

Example 3

Preparation of two-layer type multicolor thermosensitive recording material

In the same manner as in Example 1 except that 10 parts of the F liquid was used instead of 10 parts of the D liquid in the high-temperature coloring coating liquid, and 30 parts of the F liquid was used instead of 30 parts of the D liquid in the low-temperature coloring coating liquid, A multicolor heat-sensitive recording material in which the heat-sensitive recording layer was composed of two coloring layers was prepared.

Comparative Example 1

Preparation of two-layer type multicolor thermosensitive recording material

Multicolor thermal recording in which the thermosensitive recording layer consists of two color developing layers in the same manner as in Example 1 except that 10 parts of solution A was used instead of 10 parts of solution A in the low-temperature color forming coating solution used in Example 1. Materials were made.

Comparative Example 2

Preparation of two-layer type multicolor thermosensitive recording material

Multicolor thermal recording in which the thermosensitive recording layer consists of two color developing layers in the same manner as in Example 2 except that 40 parts of Solution A was used instead of 40 parts of Liquid A in the low-temperature coloring coating solution used in Example 2. Materials were made.

Comparative Example 3

Preparation of two-layer type multicolor thermosensitive recording material

In the low-temperature color-forming coating liquid used in Example 3, color formation of two heat-sensitive recording layers was performed in the same manner as in Example 3 except that 10 parts of Liquid B was used instead of 10 parts of Liquid A A multicolor heat-sensitive recording material composed of layers was produced.

Table 1 shows the structures of the heat-sensitive recording layers in the multicolor heat-sensitive recording materials of Examples 1 to 3 and Comparative Examples 1 to 3.

Table 1

Production Example 3

Preparation of Dispersion of Electron-donating Dye Precursor Particles Provided with Color-Controlling Layer 3-Ethylamino 6-methyl-17- (3-trifluoromethylarino) fluoran, an electron-donating dye precursor that develops black color 5 parts were pulverized in a ball mill together with 90 parts of a 2.5% aqueous polybutyl alcohol solution to obtain a dye precursor particle dispersion having a volume average particle diameter of 1; zm. Next, the dispersion was transferred to a polymerization vessel, to which 2 parts of methyl methacrylate and 0.5 part of ethylene dalichol dimetharate were added, and the temperature was raised to 70 ° C. with stirring. To this was added 2.5 parts of a 2.5% aqueous potassium persulfate solution as a polymerization initiator, and the mixture was reacted for 8 hours while continuing to stir. Then, the mixture was cooled to room temperature to obtain a dispersion liquid (hereinafter referred to as H liquid) of electron-donating dye precursor particles provided with a color-developing layer on the surface.

Example 4

Preparation of single-layer multicolor thermosensitive recording material

10 parts of solution A, 40 parts of solution D, and 40 parts of solution G obtained in Preparation Example 2, 60 parts of solution H obtained in Preparation Example 3, and a 10% aqueous solution of polyvinyl alcohol as a binder 200 parts and 100 parts of a 30% dispersion of calcium carbonate (manufactured by Shiraishi Industry Co., Ltd.) as a pigment were mixed to obtain a multicolor heat-sensitive coating liquid. On the coated paper prepared in Preparation Example 1, a multicolor heat-sensitive coating solution was applied at 8 g / m ² (dry), and dried at 60 ° C. to form a multicolor coloring layer. Thereafter, a force-rendering treatment was performed so that the Bekk smoothness of the coated surface was 400 to 500 seconds, to produce a multicolor heat-sensitive recording material in which the heat-sensitive recording layer was composed of one color-developing layer.

Example 5

Preparation of single-layer multicolor thermosensitive recording material

A multicolor heat-sensitive recording material was prepared in the same manner as in Example 4, except that 40 parts of solution E was used instead of 40 parts of solution D in the multicolor heat-sensitive coating liquid. did.

Example 6

Preparation of single-layer multicolor thermosensitive recording material A multicolor heat-sensitive recording material was prepared in the same manner as in Example 4 except that 40 parts of solution F was used instead of 40 parts of solution D in the multicolor heat-sensitive coating liquid. did.

Comparative Example 4

Preparation of single-layer multicolor thermosensitive recording material

A multi-color heat-sensitive recording layer comprising a single color-developing layer in the same manner as in Example 4, except that 10 parts of solution B was used instead of 10 parts of solution A in the multi-color heat-sensitive coating liquid used in Example 4. A recording material was produced.

Comparative Example 5

Preparation of single-layer multicolor thermosensitive recording material

Multicolor heat-sensitive recording layer comprising a single color developing layer in the same manner as in Example 5 except that 10 parts of solution B was used instead of 10 parts of solution A in the multicolor heat-sensitive coating liquid used in Example 5. A recording material was produced.

Comparative Example 6

Preparation of single-layer multicolor thermosensitive recording material

A multicolor heat-sensitive recording layer comprising a single color-developing layer in the same manner as in Example 6 except that 10 parts of solution B was used instead of 10 parts of solution A in the multicolor heat-sensitive coating liquid used in Example 6. A recording material was produced.

Table 1 shows the structure of the multicolor thermosensitive coloring layer in the single-layer type multicolor thermosensitive recording materials obtained in Examples 4 to 6 and Comparative Examples 4 to 6.

Table 1 2 Multicolor thermosensitive coloring layer

Low-temperature coloring dye precursor: 3-di_n-butylamine 6-methyl-7-bromofluorane (Solution A)

High-temperature coloring dye precursor provided with a coloring control layer: 3-Jetylamino-1

6-Methyl-7- (3-trifluoromethylarino) fluoran Example 4

(H solution)

Electron-accepting compound: 2,2-bis (4-hydroxyphenyl) propane (D solution)

Sensitizer: 2-benzyloxynaphthalene (Solution G)

Low-temperature coloring dye 'Precursor: 3-di-n-butylaminow 6-methyl-7-bromofluoran (Solution A)

6-methyl-7- (3-trifluoromethylarino) fluoran Example 5

(H solution)

Electron-accepting compound: Bis (3-arylu 4-hydroxy sulfide) sulfone (E solution)

Sensitizer: 2-benzyloxynaphthalene (G solution)

Low-temperature coloring dye precursor: 3-di-n-butylamino-6-methyl-7-bromofunolelane (Solution A)

High-temperature coloring dye precursor provided with a coloring control layer: 3—Jetylamino—

6-Methyl-1- (3-trifluoromethylarino) fluoran Example 6

(H solution)

Electron accepting compound: 2,4-bis (phenylsulfonyl) phenol (Solution F)

Sensitizer: 2-benzyloxynaphthalene (G solution)

Low-temperature chromogenic dye precursor: 3—Jetylamino _ 7 _ black mouth fluoran (Solution B)

High-temperature chromogenic dye precursor provided with a chromogenic layer: 3-Jetylamino-

6-Methyl-7- (3-tri-Funoleolomethylanilino) Fluoran Comparative Example 4

(H solution)

Electron-accepting compound: 2,2-bis (4-hydroxyphenyl) propane (Solution D)

增 Sensitives: 2-benzyloxynaphthalene (G solution)

Low-temperature chromogenic dye 'Precursor: 3-Jetylamino _ 7-Black mouth Fluoran (Solution B)

6-Methyl-7- (3_Trifluoromethylarino) Fluorane Comparative Example 5 (H solution)

Electron-accepting compound: Bis (3-arylu-4-hydroxyphenyl) sunorehon (E solution)

Sensitizer: 2-benzyloxynaphthalene (Solution G)

Low-temperature chromogenic dye precursor: 3-Jetylamine 7-Black Fluorane (Solution B)

6-methyl-7- (3-trifluoromethylarino) fluoran Comparative Example 6

(H solution)

Electron-accepting compound: 2,4-bis (phenylsulfonyl) phenol (F solution)

Sensitizer: 2-benzyloxynaphthalene (G solution) Test 1 Color development test

Thermal facsimile printing tester (TH) equipped with a thermal head (main scanning line density 8 dot / mm, resistance value 790 Ω) to the multicolor thermal recording materials of Examples 1 to 6 and Comparative Examples 1 to 6 Using a PMD (manufactured by Okura Electric Co., Ltd.), an applied voltage of 20 volts and an applied pulse of 0.6 milliseconds were used to print a low-temperature red image. At an applied voltage of 20 volts, an applied pulse of 1.5 milliseconds printed a high-temperature black image. The color tone of each printed area was visually observed. The density of the printed area was measured using a reflection densitometer (RD918, manufactured by Macbeth), and the filter hole position was measured with magenta for low-temperature coloring and black for high-temperature coloring. The results are shown in Table 13. If the low-temperature color is a clear red color with a reflection density of 1.10 or more and the high-temperature color is a non-reddish black color with a reflection density of 1.20 or more, color separation is good and there is no practical problem. It is.

Test 2 Edge test

Using the same printing device as in Test 1 on the multicolor thermal recording materials of Examples 1 to 6 and Comparative Examples 1 to 6, main scanning 2 dots at an applied voltage of 1.0 msec, applied voltage of 20 volts, Sub-operation A black image consisting of 50 dots was printed. The width of the red-colored border generated along the sub-operation direction of the black image was observed and measured with a digital microscope (VH-700, manufactured by KEYENCE CORPORATION). Table 14 shows the results. If the width of the border is 4 ◦ μra or less, the black colored thin line does not look reddish and is at a level that is practically acceptable.

Test 3 Heat resistance storage test of color image

Regarding the multicolor heat-sensitive recording materials of Examples 1 to 6 and Comparative Examples 1 to 6, the red color image printed in the same manner as the printing method of Test 1 was compared with the color density difference before and after storage at 60 ° C for 24 hours. Were compared. The density was measured using a reflection densitometer (RD918, manufactured by Macbeth), and the position of the filter hole was measured in magenta. The results are shown in Table 14 as the concentrations after the test. If the concentration after the test is 0.80 or more, there is no practical problem. Test 4 Preservation test of colorant image for plasticizer resistance

For the multicolor heat-sensitive recording materials of Examples 1 to 6 and Comparative Examples 1 to 6, a red-colored image printed in the same manner as in Test 1 was obtained by using a soft bursit chloride (product name: soft card case, manufactured by KOKUYO Co., Ltd.). ) Was compared with the color density difference before and after storage at 20 ° C. and 60% RH for 14 days in a state of contact with 4.0 g Z cm ² . The density was measured using a reflection densitometer (RD918, manufactured by Macbeth), and the position of the filter hole was measured with magenta in the red image. The results are shown in Table 14 as the concentrations after the test. If the concentration after the test is 0.80 or more, there is no practical problem. Table 1 3 Low-temperature color tone Low-temperature color density High-temperature color tone High-temperature color density Example 1 vivid red 1.1 3 1.40 Example 2 vivid red 1.1 9 black 1.4 3 Example 3 vivid red 1 1 7 Black 1. 4 2 Example 4 Brilliant Red 1. 1 9 Ri 1.44 Example 5 Brilliant Red 1.2 3 M 1. 4 7 Example 6 Brilliant Red 1.2 2 M 1. 46 Comparative Example 1 Vermilion 0.99 6 Reddish black 1.3 5 Comparative Example 2 Vermilion 0.99 9 Reddish black 1.3 3 Comparative Example 3 Vermilion 0.98 Reddish black 1. 3 8 Compare Example 4 Vermilion 1.01 Reddish black 1.3 9 Comparative Example 5 Vermilion 1.06 Reddish black 1.42 Comparative Example 6 Vermilion 1.03 Reddish black 1.43 Table 1 4

Industrial applicability

As is clear from Tables 1 and 3, the multicolor heat-sensitive recording materials of Examples 1 to 3 give clearer red and black images, have excellent color separation, and have a red image. Had excellent storage stability. In particular, in Examples 2 and 3, a multicolor heat-sensitive recording material having a clearer red image and excellent storage stability was obtained as compared with Example 1. In addition, in the multicolor heat-sensitive recording materials of Examples 4 to 6, not only a vivid red image color and a black image were obtained, but also the red border around the black image portion was small and excellent in color separation. In addition, a multicolor heat-sensitive recording material having excellent red image preservability was obtained. In particular, in Examples 5 and 6, a multicolor heat-sensitive recording material having a clearer red image and excellent storability as compared with Example 4 was obtained. In contrast to the above examples, the multicolor heat-sensitive recording materials of Comparative Examples 1 to 6 lack the sharpness of the low-temperature color image, and the high-temperature color image is also reddish. The peripheral red border was large and color separation was insufficient. Also, the preservability of the red image was not practically sufficient. As shown by the above results, the multicolor heat-sensitive recording material of the present invention has a clear color tone, excellent color separation properties, and excellent image storability, and is extremely useful in practical use.

Claims

The scope of the claims

1. A heat-sensitive recording layer is provided on a support, and the heat-sensitive recording layer comprises two or more kinds of usually colorless or light-colored electron-donating dye precursors that develop different colors and the electron-donating dye precursors. In a multicolor heat-sensitive recording material containing an electron-accepting compound capable of forming a color,

A multicolor heat-sensitive recording material, characterized in that one of the electron-donating dye precursors is 3-di-n-butylamino-6-methyl-7-bromofluoran.

2. The electron-accepting compound is characterized in that it is at least one selected from a compound represented by the following general formula (I) and bis (3-aryl-14-hydroxyphenyl) sulfone. The multicolor thermal recording material according to claim 1. General formula (I)

[In the formula (I), X represents a hydrogen atom or a lower alkyl group;

R \ R ² and R ³ may be the same or different and each represents a hydrogen atom, a halogen atom, a hydroxyl group, a lower alkyl group, or a cycloanolekyl group;

R ⁷ is a hydrogen atom or a general formula (II)… ( ^π )

Is a group represented by ]

3. The multicolor heat-sensitive recording material according to claim 2, wherein the electron-accepting compound represented by the general formula (I) is 2,4-bis (phenylsulfonyl) phenol.

4. The multicolor heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer comprises two layers: a low-temperature coloring layer and a high-temperature coloring layer.

5. The low-temperature color-forming layer contains 3-di-n-butylamino-6-methyl-17-bromofluorane as a red color dye precursor and 2,2-bis (4-hydroxyphene) as an electron accepting compound. Nore) Propane, bis (3-arynole-4—hydroxyphene-norre) snorehon or 2,4-bis (pheninole sulfonyl) phenol, 2-benzoyloxynaphthalene as sensitizer ,

The high-temperature color-forming layer is composed of 3-methylethylamine 6-methyl-7- (3-trifluoromethylarino) fluorane as a black color dye precursor, and 2,2-bis (4-hydroxyphenyl) as an electron-accepting compound. The multicolor heat-sensitive recording material according to claim 4, characterized in that it contains propane, bis (3-aryloxy-4-hydroxyphenyl) snorehon or 2,4-bis (phenylsulfol) phenol. .

6. The multicolor heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer comprises one layer of a multicolor coloring layer.

7. At least one of the electron-donating dye precursors has an unsaturated carbon The multicolor heat-sensitive recording material according to claim 6, wherein the heat-sensitive recording layer is present in the heat-sensitive recording layer in a state of particles provided with a color-developing layer obtained by polymerizing a compound having an elemental bond.

8. The multicolor color-forming layer is composed of 3-di-n-butylamino-6-methyl-7-bromofluorane as a low-temperature red color-forming dye precursor, and 3-ethylethylamino as a high-temperature black color-forming dye precursor provided with a color control layer. One 6-methyl-7- (3-trifluoromethylarino) fluoran as an electron accepting compound, 2,2-bis (4-hydroxyphenyl) propane, bis (3-arinole_4—hydroxy) The multicolor heat-sensitive recording material according to claim 6, characterized in that it contains 2-benzoylinaphthalene as a sensitizer, which comprises elegre) snorefon or 2,4-bis (phenylsulfol) phenol.