JP2002067511A - Multicolor thermosensitive recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multicolor thermosensitive recording material having good color separation of a low temperature printed part and a high temperature printed part and having good resolution, without color bleeding of a peripheral part of the high temperature printed part in an additive multicolor thermosensitive recording material for color developing in a different color tone. SOLUTION: The multicolor thermosensitive recording material comprises three or more types of electron donative dye precursor for color developing in different color tones from each other, and a thermosensitive recording layer containing an electron acceptive developer for color developing the dye precursor at a heating time on a support. The recording material also comprises (1) one or more types of low temperature color developing dye precursor dispersing particles, and (2) two or more types of high temperature color developing dye precursors each having a color developing regulating layer obtained by addition polymerizing a vinyl monomer on surfaces so that one of the types is a low temperature color complementary color dye precursor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an additive-type multicolor heat-sensitive recording material which develops different colors at low and high temperatures depending on differences in heating conditions such as coloration temperature. More specifically, the present invention relates to a multicolor heat-sensitive recording material having good color separation between a low-temperature color and a high-temperature color when heated at a high temperature.

[0002]

2. Description of the Related Art A thermosensitive recording material generally comprises a support provided with a thermosensitive recording layer mainly composed of an electron-donating, usually colorless or pale-colored dye precursor and an electron-accepting developer.
By heating with a thermal head, hot pen, laser light, etc., the dye precursor and the developer react instantaneously to obtain a colored image, the recording device is simple and easy to maintain, and noise is generated. Measurement recorder, facsimile, printer, computer terminal, PO
It is used in a wide range of fields, such as S label machines and ticket vending machines.

With the diversification of uses of such heat-sensitive recording materials, multicolor heat-sensitive recording materials capable of developing two or more colors depending on the heating temperature are desired. Additive-type multicolor heat-sensitive recording paper which develops a mixed color has high practicality, and many proposals have been made to improve mutual color separation.

[0004] As a typical method for realizing such multicolored thermal recording, a method of providing two or more thermosensitive layers is as follows.
(1) A method in which dye precursors that form colors different from each other are layered into a high-temperature coloring layer and a low-temperature coloring layer, and a mixed color of the low-temperature hue and the high-temperature hue is obtained at the time of high-temperature printing following low-temperature printing (
54-097048). In this method, the color separation is good because the high-temperature coloring layer and the low-temperature coloring layer are separated, but the sensitivity is low because the high-temperature coloring layer is in the lower layer. The color mixture of high-temperature colors (black colors) was inevitable during printing, and the color became blackish red, and color separation was still insufficient. To improve this color separation,
(2) Dye precursors that develop colors different from each other are separated into a high-temperature coloring layer and a low-temperature coloring layer via a decoloring agent layer, and during high-temperature printing following low-temperature printing, printing is performed while erasing the low-temperature coloring layer. Erasing method (Japanese Unexamined Patent Publication No. 55-139470,
7-178791). In this method, the color separation is very good because the low-temperature color is erased during high-temperature coloring, but the presence of the decoloring agent in the heat-sensitive layer raises concerns about the long-term storage of images. There is still a disadvantage that the production cost is high.

On the other hand, as a method for obtaining two colors having good color separation with a single layer of the heat-sensitive layer, (3) a plurality of dye precursors which develop colors different from each other are contained in the same layer, and at least There is a method of encapsulating one type in a microcapsule (Japanese Patent Laid-Open No. 8-282115). In this method, color separation is good because the dye precursors are isolated from each other by the capsule membrane, but since the oily liquid is encapsulated in the microcapsules, the capsules are destroyed by the pressure and friction during handling and the background coloration There are drawbacks that occur.

Further, (4) a method in which a high-temperature coloring dye precursor is formed into composite fine particles of at least one polymer substance selected from polyurea and polyurethane, and is used in combination with solid fine particles of a low-temperature dye precursor (Japanese Patent Application Laid-Open No. 9-1997). No. 142025) has also been proposed. In this method, in order to completely cover the dye precursor, a large amount of polyurea or polyurethane is contained, and color separation is good, but there is a difficulty in insufficient color development sensitivity. Further, (5) a method of covering at least one or more of two or more dye precursors that develop colors with different color tones with a color control layer polymerized with a compound having an unsaturated carbon bond (JP-A-11-311)
No. 01118) has been proposed by the present applicant. According to this method, the dye precursor particles are covered with a solid thin polymer film (color control layer), and the color control sensitivity can be easily controlled by the color control layer, and the color separation can be controlled. However, there is a problem that color fringing occurs, which is a phenomenon in which the periphery of a character is surrounded by a low-temperature color during high-temperature printing, resulting in insufficient color separation and lack of sharpness of an image. .

[0007]

SUMMARY OF THE INVENTION The present invention relates to a color-added multicolor heat-sensitive recording material which develops different color tones, in which the color separation between a low-temperature printing portion and a high-temperature printing portion is good, and when a high-temperature printing is performed, the area around the character is improved. Is a high-resolution multicolor heat-sensitive recording material that is free from color bleeding and is a phenomenon surrounded by low-temperature colors.

[0008]

The object of the present invention is to provide at least three kinds of electron-donating dye precursors which form colors different from each other on a support, and an electron-accepting developer which develops the dye precursors upon heating. Multicolor thermosensitive recording material provided with a thermosensitive recording layer containing a coloring agent and an agent, the dye precursor is subjected to addition polymerization of 1) one or more kinds of low-temperature coloring dye precursor dispersed particles and 2) a vinyl monomer. This can be achieved by using two or more kinds of high-temperature coloring dye precursors having the coloring control layers obtained as described above on their respective surfaces. In particular, the color separation from the low-temperature color at the time of high-temperature printing is improved by making one of the high-temperature coloring dye precursors having the color-control layer on the surface a complementary color of the low-temperature coloring dye precursor. Furthermore, by making the color control layer formed on the surface of the complementary dye precursor higher in sensitivity than the color control layer formed on other dye precursors, the color bleeding around the printed portion is eliminated and the characters are removed. The resolution is improved, and one of the high-temperature coloring dye precursors is used as a black-based dye precursor, or the low-temperature coloring dye precursor is combined with a red-based or blue-based color. A multicolor heat-sensitive recording material having good color separation and good character resolution can be obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The multicolor heat-sensitive recording material of the present invention is a color-forming material obtained by addition-polymerizing a vinyl monomer and one or more dispersed particles of a low-temperature coloring dye precursor which forms a low-temperature color. A thermosensitive recording layer containing two or more types of dye precursors for high-temperature coloring having a control layer on the surface and an electron-accepting developer for coloring these dye precursors upon heating is coated on an arbitrary support. It becomes.

Since the present invention is a color-added multicolor heat-sensitive recording material, the low-temperature coloring dye precursor-dispersed particles react with the electron-accepting developer to develop a low-temperature color by heating, and further to a high temperature. High temperature side (low sensitivity side) when heated
The dye precursor for high-temperature coloring, whose thermal sensitivity is controlled, melts to form a color with the electron-accepting developer, and exhibits a color mixture with the low-temperature color. A phenomenon surrounded by low-temperature colors, that is, "color bleeding" is inevitably generated around the portion where the mixed color is generated due to the diffusion of heat. In the present invention, the color tone is controlled by utilizing the combination of the dye precursor and the function of the color control layer, and the "color blur" is reduced by controlling the heat sensitivity of the color control layer.

The dye precursor for low-temperature coloring of the present invention has a color tone of reddish to yellowish or one of greenish to bluedish colors in appropriate combination. Since the multicolor heat-sensitive recording material tends to have a dark color due to color mixture at a high temperature, a light red-yellow color is preferably used at a low temperature. In general, printing in the low-temperature part is recording of characters and image information, but solid printing or background pattern printing with a thermal head may be considered as the background of printing in the high-temperature part. Light colors are preferred for contrast.

These low-temperature coloring dye precursors are used in the form of dispersed particles, and can be obtained by dispersion by a dry grinding method or a wet grinding method known in the field of heat-sensitive recording materials. In general, the particles are wet-pulverized by a sand mill, a ball mill, or the like using water as a dispersion medium to a particle size of 0.1 μm or more and 10 μm or less, preferably 0.3 μm or more and 2 μm or less. When the particle size is smaller than 0.1 μm, low-temperature background fogging is caused, and when the particle size is larger than 10 μm, the coloring sensitivity is deteriorated, which is not preferable.

Here, for low-temperature coloring used in the present invention,
Specific examples of the dye precursor for high-temperature coloring include red, yellow, blue, green, and black colors, but are not limited thereto.

The reddish dye precursor is 3,3-bis (1-n-butyl-2-methylindol-3-yl)
Phthalide, 3,3-bis (1-n-butyl-2-methylindol-3-yl) tetrachlorophthalide, 3,3
-Bis (1-n-butylindol-3-yl) phthalide, 3,3-bis (1-n-pentyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-
Hexyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-n-octyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-methyl-2-methylindole) -3-yl) phthalide, 3,
3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,3-bis (1-propyl-2-methylindol-3-yl) phthalide, 3,3-bis (2
Methylindol-3-yl) phthalide, rhodamine B
-Anilinolactam, rhodamine B- (o-chloroanilino) lactam, rhodamine B- (p-nitroanilino) lactam, 3-diethylamino-5-methyl-7-
Dibenzylaminofluoran, 3-diethylamino-6
-Methyl-7-chlorofluoran, 3-diethylamino-6-methoxyfluoran, 3-diethylamino-6
Methylfluoran, 3-diethylamino-6-methyl-
7-chloro-8-benzylfluoran, 3-diethylamino-6,7-dimethylfluoran, 3-diethylamino-6,8-dimethylfluoran, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7- Methoxyfluoran, 3-diethylamino-7- (N-acetyl-N-methyl) aminofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-
7-methylethoxyfluoran, 3-diethylamino-
7-p-methylphenylfluoran, 3-diethylamino-7,8-benzofluoran, 3-diethylaminobenzo [a] fluoran, 3-diethylaminobenzo [c] fluoran, 3-dimethylamino-7-methoxyfluoran, 3-dimethylamino-6-methyl-7-chlorofluorane, 3-dimethylamino-7-methylfluorane, 3-dimethylamino-7-chlorofluorane,
3- (N-ethyl-p-toluidino) -7-methylfluoran, 3- (N-ethyl-N-isoamyl) amino-
6-methyl-7-chlorofluorane, 3- (N-ethyl-N-isoamyl) amino-7,8-benzofluoran, 3- (N-ethyl-N-isoamyl) amino-7-
Methylfluoran, 3- (N-ethyl-Nn-octyl) amino-6-methyl-7-chlorofluoran, 3-
(N-ethyl-NN-octyl) amino-7,8-benzofluoran, 3- (N-ethyl-Nn-octyl) amino-7-methylfluoran, 3- (N-ethyl-N -N-octyl) amino-7-chlorofluoran,
3- (N-ethyl-N-4-methylphenyl) amino-
7,8-benzofluoran, 3- (N-ethyl-N-4
-Methylphenyl) amino-7-methylfluoran, 3
-(N-isopentyl-N-ethyl) amino-7,8-
Benzofluorane, 3- (N-ethoxyethyl-N-ethyl) amino-7,8-benzofluoran, 3- (N-
(Ethoxyethyl-N-ethyl) amino-7-chlorofluorane, 3-n-dibutylamino-6-methyl-7-chlorofluorane, 3-n-dibutylamino-7,8-benzofluoran, 3-n -Dibutylamino-7-chlorofluorane, 3-n-dibutylamino-7-methylfluoran, 3-diallylamino-7,8-benzofluoran, 3-diallylamino-7-chlorofluoran, 3-
Di-n-butylamino-6-methyl-7-bromofluorane, 3-cyclohexylamino-6-chlorofluoran, 3-pyrrolidylamino-7-methylfluoran, 3
-Ethylamino-7-methylfluoran, 3-diethylamino-benzo [a] fluoran, 3-N-ethyl-N
-Isoamylamino-benzo [a] fluoran, 3-N
-Ethyl-N-p-methylphenylamino-7-methylfluoran, 3-dibutylamino-6-methyl-7-bromofluorane, 3,6-bis (diethylaminofluoran) -γ- (4′-nitro ) Anilinolactam.

The yellow dye precursors include 3,6-dimethoxyfluoran, 3-cyclohexylamino-6-chlorofluoran, 2,6-diphenyl-4- (4-dimethylaminophenyl) -pyridine, , 2-bis (4-
(2- (4-diethylaminophenyl) quinazolyl) oxyphenyl) propane, 4-chloro-N- (4- (N
-(4-methylbenzyl) -N-methylamino) benzylidene) aniline, 1- (2-quinolyl) -2- (3-
Methoxy-4-dodecyloxyphenyl) ethene, 1-
(4-n-dodecyloxy-3-methoxyphenyl)-
2- (2-quinolyl) ethylene.

The blue dye precursor includes 3- (1-ethyl-2-methylindol-3-yl) -3- (4-
Diethylaminophenyl) phthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-methyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindo -Ru-3-yl) -3- (2-ethoxy-4-aminophenyl) -4
-Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-methylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methyl) Indole-3-yl) -3- (2-ethoxy-4-ethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2 -Ethoxy-4-dimethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-
Diethylaminophenyl) -4-azaphthalide, 3-
(1-Ethyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-dipropylaminophenyl)-
4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-dibutylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2- Methylindol-3-yl) -3- (2-
Ethoxy-4-dipentylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-
3-yl) -3- (2-ethoxy-4-dihexylaminophenyl) -4-azaphthalide, 3- (1-ethyl-
2-methylindol-3-yl) -3- (2-ethoxy-4-dihydroxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3-
Yl) -3- (2-ethoxy-4-dichloroaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4
-Dibromoaminophenyl) -4-azaphthalide, 3-
(1-Ethyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-diallylaminophenyl) -4
-Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-dihydroxyaminophenyl) -4-azaphthalide, 3- (1-
Ethyl-2-methylindol-3-yl) -3- (2
-Ethoxy-4-dimethoxyaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethoxyaminophenyl) -4- Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-dicyclohexylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindo -Ru-3-yl) -3- (2-ethoxy-4-dimethylethoxyaminophenyl) -4-azaphthalide, 3- (1-
Ethyl-2-methylindol-3-yl) -3- (2
-Ethoxy-4-diethylethoxyaminophenyl)-
4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylbutoxyaminophenyl) -4-azaphthalide, 3-
(1-Ethyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-dimethylcyclohexaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-
Methylindol-3-yl) -3- (2-ethoxy-
4-dimethoxycyclohexylaminophenyl) -4-
Azaphthalide, 3- (1-ethyl-2-methylindo-
Ru-3-yl) -3- (2-ethoxy-4-pyrrolidylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (3- Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3-
Yl) -3- (2,3-diethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-
2-methylindol-3-yl) -3- (4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-
Chloro-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3-
Yl) -3- (3-Chloro-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-bromo-4-diethylaminophenyl ) -4-azaphthalide, 3- (1
-Ethyl-2-methylindol-3-yl) -3-
(3-Bromo-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethyl-4-diethylaminophenyl) -4-azaphthalide , 3- (1-ethyl-2)
-Methylindol-3-yl) -3- (2-propyl-4-diethylaminophenyl) -4-azaphthalide;
3- (1-ethyl-2-methylindol-3-yl)
-3- (3-Methyl-4-diethylaminophenyl)-
4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-nitro-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methyl) Indole-3-yl) -3- (2-allyl-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2- Hydroxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-cyano-4-
Diethylaminophenyl) -4-azaphthalide, 3-
(1-Ethyl-2-methylindol-3-yl) -3
-(2-cyclohexylethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2
-Methylindole-3-yl) -3- (2-methylethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-methylindole-3-
Yl) -3- (2-cyclohexylethyl-4-diethylaminophenyl) -4-azaphthalide, 3- (2-ethylindole-3-yl) -3- (2-ethoxy-4
-Diethylaminophenyl) -4-azaphthalide, 3-
(1-Ethyl-2-chloroindol-3-yl) -3
-(2-ethoxy-4-diethylaminophenyl) -4
-Azaphthalide, 3- (1-ethyl-2-bromoindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-ethylindo -R-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-propylindole-3
-Yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-
Methoxyindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide;
3- (1-ethyl-2-ethoxyindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-2-phenylindole- 3-yl) -3- (2-ethoxy-4
-Diethylaminophenyl) -4-azaphthalide, 3-
(1-Ethyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-diethylaminophenyl) -7
-Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4,7-diazaphthalide, 3- (1
-Ethyl-4,5,6,7-tetrachloro-2-methylindole-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1
-Ethyl-4-nitro-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-4-methoxy-2-methyl) Indole-3-yl) -3- (2-
Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethyl-4-methylamino-2-methylindol-3-yl) -3- (2-ethoxy-4
-Diethylaminophenyl) -4-azaphthalide, 3-
(1-ethyl-4-methyl-2-methylindole-3
-Yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4 -Azaphthalide, 3- (1-chloro-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-bromo-2-methylindo -Rule-3-
Yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-methyl-2-methylindol-3-yl) -3- (2-ethoxy-4
-Diethylaminophenyl) -4-azaphthalide, 3-
(1-Methyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-diethylaminophenyl) -7
-Azaphthalide, 3- (1-propyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-butyl-2-methylindo -Ru-3-yl) -3- (2-
Ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-butyl-2-indole-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- ( 1-pentyl-2-methylindol-3-yl) -3- (2-ethoxy-4
-Diethylaminophenyl) -4-azaphthalide, 3-
(1-hexyl-2-methylindol-3-yl)-
3- (2-ethoxy-4-diethylaminophenyl)-
4-azaphthalide, 3- (1-hexyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1-
Octyl-2-methylindol-3-yl) -3-
(2-ethoxy-4-diethylaminophenyl) -4-
Azaphthalide, 3- (1-octyl-2-methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1-octyl-2-methylindo- Ru-3-yl) -3- (2-
Ethoxy-4-diethylaminophenyl) -4,7-diazaphthalide, 3- (1-nonyl-2-methylindo-
Ru-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-methoxy-2-methylindol-3-yl) -3- (2-ethoxy- 4-diethylaminophenyl) -4-azaphthalide, 3- (1-ethoxy-2-methylindole-3
-Yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide, 3- (1-phenyl-2)
-Methylindol-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -4-azaphthalide;
3- (1-pentyl-2-methylindole-3-yl) -3- (2-ethoxy-4-diethylaminophenyl) -7-azaphthalide, 3- (1-heptyl-2-methylindole- 3-yl) -3- (2-ethoxy-4
-Diethylaminophenyl) -7-azaphthalide, 3-
(1-Nonyl-2-methylindol-3-yl) -3
-(2-ethoxy-4-diethylaminophenyl) -7
-Azaphthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-dimethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl) -6-dimethyl Aminophthalide,
3- (1-ethyl-2-methylindol-3-yl)
-3- (4-Diethylamino-2-n-hexyloxyphenyl) -4-azaphthalide.

Examples of green dye precursors include 3- (N-ethyl-NN-hexyl) amino-7-anilinofluoran and 3- (N-ethyl-Np-tolyl) amino-7.
-(N-phenyl-N-methyl) aminofluoran, 3
-(N-ethyl-NN-propyl) amino-7-dibenzylaminofluoran, 3- (N-ethyl-NN-
Propyl) amino-6-chloro-7-dibenzylaminofluoran, 3- (N-ethyl-N-4-methylphenyl) amino-7- (N-methyl-N-phenyl) aminofluoran, 3- ( N-ethyl-4-methylphenyl)
Amino-7-dibenzylaminofluoran, 3- (N-
Ethyl-4-methylphenyl) amino-6-methyl-7
-Dibenzylaminofluoran, 3- (N-ethyl-4
-Methylphenyl) amino-6-methyl-7- (N-methyl-benzyl) aminofluoran, 3- (N-methyl-Nn-hexyl) amino-7-anilinofluoran, 3- (N- Propyl-Nn-hexyl) amino-
7-anilinofluoran, 3- (N-ethoxy-Nn
-Hexyl) amino-7-anilinofluoran, 3-
(Nn-pentyl-N-allyl) amino-6-methyl-7-anilinofluoran, 3- (Nn-pentyl-
N-allyl) amino-7-anilinofluoran, 3-n
-Dibutylamino-6-chloro-7- (2-chloroanilino) fluoran, 3-n-dibutylamino-6-methyl-7- (2-chloroanilino) fluoran, 3-n-
Dibutylamino-6-methyl-7- (2-fluoroanilino) fluoran, 3-n-dibutylamino-7- (2
-Chloroanilino) fluoran, 3-n-dibutylamino-7- (2-chlorobenzylanilino) fluoran,
3,3-bis (4-diethylamino-2-ethoxyphenyl) -4-azaphthalide, 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino) phthalide, 3-diethylamino -6-methyl-7-benzylamino-fluoran, 3-diethylamino-6-methyl-7-dibenzylaminofluoran, 3
-Diethylamino-6-methyl-7-n-octylaminofluoran, 3-diethylamino-6-methyl-7-
(N-cyclohexyl-N-benzylamino) fluoran, 3-diethylamino-6-methyl-7- (2-chloroanilino) fluoran, 3-diethylamino-6-methyl-7- (2-trifluoromethylanilino) fluoran, 3-diethylamino-6-methyl-7- (3-trifluoromethylanilino) fluoran, 3-diethylamino-6-methyl-7- (2-ethoxyanilino) fluoran, 3-diethylamino-6-methyl-7- (4
-Ethoxyanilino) fluoran, 3-diethylamino-6-chloro-7- (2-chloroanilino) fluoran, 3-diethylamino-6-chloro-7-dibenzylaminofluoran, 3-diethylamino-6-chloro-
7-anilinofluoran, 3-diethylamino-6-ethylethoxy-7-anilinofluoran, 3-diethylamino-7-anilinofluoran, 3-diethylamino-7-methylanilinofluoran, 3-diethylamino- 7-dibenzylaminofluoran, 3-diethylamino-7-n-octylaminofluoran, 3-diethylamino-7-p-chloroanilinofluoran, 3-diethylamino-7-p-methylphenylanilinofluoran, 3-Diethylamino-7- (N-cyclohexyl-
N-benzylamino) fluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3-diethylamino-7- (3-trifluoroanilino) fluoran, 3-diethylamino-7- (2-trifluoromethylanilino ) Fluoran, 3-diethylamino-7-
(2-ethoxyanilino) fluoran, 3-diethylamino-7- (4-ethoxyanilino) fluoran, 3-
Diethylamino-7- (2-chlorobenzylanilino)
Fluoran, 3-dimethylamino-6-chloro-7-dibenzylaminofluoran, 3-dimethylamino-6
Methyl-7-n-octylaminofluoran, 3-dimethylamino-7-dibenzylaminofluoran, 3-dimethylamino-7-n-octylaminofluoran, 3
-Dibutylamino-7- (2-fluoroanilino) fluoran, 3- [p- (p-anilinoanilino) anilino]
-6-methyl-7-chlorofluoran, 3-anilino-
7-dibenzylaminofluoran, 3-anilino-6
Methyl-7-dibenzylaminofluoran, 3-pyrrolidino-7-dibenzylaminofluoran, 3-pyrrolidino- (7-cyclohexylanilino) fluoran, 3-
Dibenzylamino-6-methyl-7-dibenzylaminofluoran, 3-dibenzylamino-7-dibenzylaminofluoran, 3-dibenzylamino-7- (2-chloroanilino) fluoran.

Examples of black color dye precursors include 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-phenylaminofluoran, and 3-dibutylamino-7. -(2-chloroanilino) fluoran, 3-dibutylamino-7- (o-chlorophenyl) aminofluoran, 3-diethylamino-
6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-phenylaminofluoran, 3
-Diethylamino-6-methyl-7-xylidinofluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3-diethylamino-7- (o-chlorophenyl) aminofluoran, 3-diethylamino-
7- (o-chlorophenyl) amino-fluoran, 3-
Diethylamino-7- (2-carbomethoxy-phenylamino) fluoran, 3- (N-cyclohexyl-N-
Methyl) amino-6-methyl-7-anilinofluoran, 3- (N-cyclohexyl-N-methyl) amino-
6-methyl-7-phenylaminofluoran, 3- (N
-Cyclopentyl-N-ethyl) amino-6-methyl-
7-phenylaminofluoran, 3- (N-isoamyl-N-ethyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7-ani Linofluoran, 3- (N-ethyl-p
-Toluidino) -6-methyl-7- (p-toluidino)
Fluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-phenylaminofluoran, 3-
(N-methyl-N-tetrahydrofurfuryl) amino-
6-methyl-7-phenylaminofluoran, 3- (N
-Ethyl-N-tetrahydrofurfuryl) amino-6
Methyl-7-phenylaminofluoran, 3-pyrrolidino-6-methyl-7-phenylaminofluoran, 3-
Pyrrolidino-6-methyl-7-p-butylphenylaminofluoran, 3-piperidino-6-methyl-7-phenylaminofluoran, 2-phenylamino-3-methyl-6- (N-ethyl-Np -Toluyl) amino-fluoran and the like.

On the other hand, the dye precursor for high-temperature coloring in the present invention is used by wrapping two or more kinds of color tone in a coloring control layer. The two or more kinds of color tones are appropriately determined depending on the target color tone at the time of high temperature, but in many cases, two or more kinds of the mixed colors are black. When the color tone of the low-temperature color is reddish to yellowish, one of the two high-temperature colors uses a dye precursor of a greenish-blue color which is a complementary color thereof, and When the color tone is greenish to blueish, if one of the two high-temperature colors uses a reddish to yellowish dye precursor, which is the complementary color, the color mixture at high temperatures is It is preferable because it can easily approach black. Furthermore, in combination with the dye precursor having a complementary color relationship, if a black-based dye precursor is used alone as the second type of high-temperature coloring dye precursor, the black color has a deep black appearance. And the color separation from the low-temperature color becomes clearer, which is preferable. When the color tone of the high-temperature color mixture is represented by a color difference value specified by JIS-Z8730 according to a measurement method specified by JIS-Z8722, an L * value <40, -5 <a * <
5, it is preferable that -3 <b * <3.

Further, in the present invention, the dye precursor for high-temperature coloring is used by wrapping two or more kinds of dyes in a coloring control layer having different coloring sensitivities. In this case, by using a dye precursor for high-temperature coloring that is a complementary color of a low-temperature color on the highest sensitivity side of the high-temperature color, a phenomenon in which the periphery of a character generated in an additive-type multicolor heat-sensitive recording material is surrounded by a low-temperature color. It has been found that the color blur is considerably reduced.
That is, as a phenomenon, color fringing occurs from the outermost side of the character in the order of low-temperature color and complementary black, and the color fringing of the low-temperature color can be controlled to such an extent that it is hardly recognized visually.

The difference in sensitivity between the color control layers having different color forming sensitivities is expressed by a single color forming starting temperature, and is expressed as 1 to 1.
20 ° C, preferably 5 to 10 ° C is good. If the difference in sensitivity is larger than this, there is no effect in reducing the apparent color blur,
Rather, a mixture of a low-temperature color and a high-temperature color on the high-sensitivity side is conspicuous around the character, and a thin line becomes thicker, resulting in a reduction in resolution.

Here, the high-temperature coloring dye precursor having a coloring control layer on the surface is prepared by converting the dye precursor to water or water-compatible methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, methyl ethyl ketone, ethylene glycol, or the like. The mixed solution of the above, using a sand mill, ball mill or the like, the particle size of the dispersed particles is 0.1μm or more and 10μ
m, preferably 0.3 μm or more and 2 μm or less, and then a vinyl monomer and a polymerization initiator are added, and if necessary, heated to form a color control layer around the dispersed particles. . Also in this case, if the particle size is smaller than 0.1 μm,
The formation of the color-developing layer is insufficient, and if it is larger than 10 μm, the color-developing sensitivity deteriorates, which is not preferable. Here, the vinyl monomer used is a compound having at least one vinyl bond (carbon-carbon double bond) in its molecule, and the vinyl bond becomes an active site and is capable of addition polymerization.

Various states are conceivable as a mixed state when the vinyl monomer is added to the dispersion of the dye precursor. That is, 1) Most of the dispersion of the dye precursor and the vinyl monomer are phase-separated to form separate phases or are in an emulsified state, but a very small amount of the vinyl monomer is a dispersion of the dye precursor. 2) A state in which the dispersion liquid of the dye precursor and the vinyl monomer are completely dissolved and completely phase-separated 3)
Examples include a state in which the vinyl monomer is completely dissolved in most or all of the dispersion, but among these states,
When polymerization is performed in a state in which a very small amount of the vinyl monomer of 1) is dissolved in the dispersion liquid of the dye precursor, the surface of the particles of the dye precursor is more polished than in the case where polymerization is performed in another state. This is a preferable state because a uniform and dense color-developing layer can be formed. Such a state can be realized by appropriately selecting the type of dispersion medium for dispersing the dye precursor particles and the type of vinyl monomer.

The vinyl monomer includes a compound having one vinyl bond and a compound having two or more vinyl bonds. By changing the content of the compound having two or more vinyl bonds, the heat sensitivity characteristic of the color control layer can be freely changed. Compared to those polymerized with a compound having only one vinyl bond, the color-controlling layer using a compound having two or more vinyl bonds together has a stronger crosslinked structure, and the color-forming start temperature when a thermosensitive recording material is formed. Can be on the high temperature side. The combination ratio of the compound having two or more vinyl bonds is preferably 1% by weight or more and 70% by weight or less, and more preferably 10% by weight or more and 50% by weight or less based on the total weight of the vinyl monomer. Within this range, it is possible to arbitrarily adjust the color development characteristics such as the color development start temperature, and it becomes easy to adjust the color separation in the multicolor heat-sensitive recording material.

The total amount of the vinyl monomer with respect to the dye precursor particles is preferably 0.5% by weight or more and 1000% by weight or less. A coating having a sufficient function as a control layer is obtained. By increasing or decreasing the amount of the vinyl monomer, the thermal sensitivity characteristic of the color control layer can be changed.

Specific examples of the compound having only one vinyl bond in the present invention include styrene, α-methylstyrene, α-methoxystyrene, m-bromostyrene and m-bromostyrene.
-Chlorostyrene, o-bromostyrene, o-chlorostyrene, p-bromostyrene, p-chlorostyrene, p
-Methylstyrene, p-methoxystyrene, 2-vinylpyridine, isobutene, 3-methyl-1-butene, butyl vinyl ether, methyl vinyl ketone, nitroethylene, vinylidene cyanide, ethylene, propylene, vinyl chloride, vinyl acetate, acrolein, Methyl acrolein, acrylamide, N-methylol acrylamide,
N, N-dimethylacrylamide, diacetoneacrylamide, N-octadecylacrylamide, ethyl α-acetoxyacrylate, ethyl α-chloroacrylate,
α-Methyl chloroacrylate, α-methyl methyl cyanoacrylate, α-methyl acrylate, benzyl acrylate, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, acrylic acid Tridecyl, acrylic acid-
2-hydroxyethyl, 2-hydroxypropyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, ethoxyethoxyethyl acrylate, methyl triglycol acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate , Cyanoethyl acrylate, ferrocenylmethyl acrylate, glycidyl acrylate, heptafluorobutyl acrylate, methyl acrylate, octyl acrylate, methyl trifluoroacrylate, 2-chloroethyl acrylate, 2-nitrobutyl acrylate, Acrylic acid, α
-Bromoacrylic acid, 2-hydroxyethylacryloyl phosphate, acrylonitrile, allyl glycidyl ether, allyl acetic acid, allyl alcohol, allyl benzene, N-allyl stearyl amide, 1-butene, 2-
Butene, N-vinylcaprolactam, ethyl N-vinylcarbamate, N-vinylcarbazole, crotonaldehyde, crotonic acid, 1,1-diphenylethylene, tetrafluoroethylene, diethyl fumarate, 1-hexene, 1-vinylimidazole, 1 -Vinyl-2-methylimidazole, indene, diethyl maleate, maleic anhydride, maleimide, methacrylamide, benzyl methacrylate, ethyl methacrylate, ferrocenylmethyl methacrylate, glycidyl methacrylate, isopropyl methacrylate, propyl methacrylate, Methacrylic acid-
n-butyl, isobutyl methacrylate, methacrylic acid-
sec-butyl, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, isodecyl methacrylate, lauryl methacrylate,
Tridecyl methacrylate, stearyl methacrylate, methyl methacrylate, phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, dimethylamino methacrylate Ethyl, diethylaminoethyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, methacrylic acid, methacryloxyethyl phosphate, polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, N-methylol methacrylamide, methacrylonitrile, methacryloyl acetone , 2-isopropenyl-2-oxazoline, 2-vinylquinoline, vinyl benzoate, vinyl dodecyl ether, vinyl Ethyl sulfoxide, vinyl formate, vinyl isobutyl ether, vinyl laurate, although vinyl phenyl ether, the present invention is not limited thereto.

Specific examples of the compound having two or more vinyl bonds include polyethylene glycol diacrylates such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and octaethylene glycol diacrylate. Acrylates, polyethylene glycol dimethacrylates such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, and tetraethylene glycol dimethacrylate, 2,2-bis (4-acryloxyethoxyphenyl) propane, 2,2- Bis (4-acryloxydiethoxyphenyl) propane, 2,2-bis (4-acryloxytriethoxyphene) B) 2,2-bis (4-acryloxypolyethoxyphenyl) propanes such as propane, 2,2-bis (4-methacryloxyethoxyphenyl) propane, 2,2-bis (4-methacryloxydiethoxyphenyl) 2,2) such as propane and 2,2-bis (4-methacryloxytriethoxyphenyl) propane
-Bis (4-methacryloxypolyethoxyphenyl) propanes, allyl acrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, polypropylene glycol diacrylate, N, N'-methylenebisacrylamide, allyl methacrylate, 1,3-butanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol dimethacrylate, Dipropylene glycol dimethacrylate, diallyl phthalate, diallyl chlorendate, butadiene, ethyl butadiene-1-carboxylate, diethyl butadiene-1,4-dicarboxylate Diallyl melamine, diallyl phthalate, N, N-divinyl aniline, divinyl ether,
Divinylbenzene, divinylnaphthalene, 1,3-butanediol dimethacrylate, isoprene, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate,
Examples include triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, tetramethylolmethanetetraacrylate, tetramethylolmethanetetramethacrylate, and the like, but the present invention is not limited thereto.

The above-mentioned vinyl compounds according to the present invention can be used alone or in combination of two or more. When used in combination of two or more, as described above,
A combination of a compound having one vinyl bond and a compound having two or more vinyl bonds is preferable, but a combination of compounds having one vinyl bond and compounds having two or more vinyl bonds can also be used.

When some or all of these vinyl monomers are methacrylates, the methacrylates and their polymers have good adhesion to the dye precursor particles provided with the color control layer, It has good solubility in the dispersion medium and good polymerizability, so it is possible to efficiently coat the surface of the dye precursor particles by addition polymerization, and furthermore, it has a function of adjusting color development characteristics such as color development start temperature. And are particularly preferably used in the present invention.

As the polymerization initiator to be added for the addition polymerization of the vinyl monomer, known ones can be used. The type of polymerization reaction is not particularly limited, such as radical polymerization, anionic polymerization and cationic polymerization. Particularly preferably used. During the polymerization, the system may be heated as required. Specific examples of the polymerization initiator for radical polymerization are shown below. Hydrogen peroxide, cumene hydroperoxide, t-butyl hydroperoxide, dicumyl peroxide, di-
Peroxides such as t-butyl peroxide, benzoyl peroxide and lauroyl peroxide, persulfates such as potassium persulfate and ammonium persulfate, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2 , 4-Dimethylvaleronitrile), 2,2'-azobis (4-methoxy-
Azo compounds such as 2,4-dimethylvaleronitrile), 2,2'-azobis (2-methylpropionamidine) dihydrochloride, and 4,4'-azobis (4-cyanovaleric acid), hydrogen peroxide and ferrous iron Combination of salt, combination of persulfate and sodium acid sulfite, combination of cumene hydroxyperoxide and ferrous salt, combination of benzoyl peroxide and diethylaniline, combination of peroxide and metal alkyl, combination of oxygen and organic metal alkyl Redox initiators and the like. These may be used not only alone but also in a mixture.

The polymerization initiator for radical polymerization is not particularly limited as long as it generates active radicals by the energy of heat or light other than those described above. In this case, it is particularly preferable to use a water-soluble polymerization initiator such as potassium persulfate, ammonium persulfate, and 2,2'-azobis (2-methylpropionamidine) dihydrochloride.

The amount of the polymerization initiator to be added is not particularly limited as long as the vinyl monomer starts the addition polymerization. Is preferably not less than 0.001 and not more than 10% by weight.

Next, the above-described electron-accepting color developer which reacts with the low-temperature coloring dye precursor dispersed particles or the high-temperature coloring dye precursor having a coloring control layer on the surface to form a color is exemplified by the following. These are used as dispersed particles in the same manner as the low-temperature coloring dye precursor.

4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-
Hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-benzyloxydiphenylsulfone, 4-hydroxy-4'-propoxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 3,4- Dihydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-benzenesulfonyloxydiphenylsulfone, 2,4-bis (phenylsulfonyl) phenol, p-phenylphenol, p-hydroxyacetophenone, 1,1-bis (p
-Hydroxyphenyl) propane, 1,1-bis (p-
Hydroxyphenyl) pentane, 1,1-bis (p-hydroxyphenyl) hexane, 1,1-bis (p-hydroxyphenyl) cyclohexane, 2,2-bis (p-
(Hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) hexane, 1,1-bis (p-hydroxyphenyl) -2-ethylhexane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane,
1,1-bis (p-hydroxyphenyl) -1-phenylethane, 1,3-di- [2- (p-hydroxyphenyl) -2-propyl] benzene, 1,3-di- [2-
(3,4-dihydroxyphenyl) -2-propyl] benzene, 1,4-di- [2- (p-hydroxyphenyl) -2-propyl] benzene, 4,4'-hydroxydiphenyl ether, 3,3'- Dichloro-4,4'-
Hydroxydiphenyl sulfide, 2,2-bis (4-
Methyl hydroxyphenyl) acetate, 2,2-bis (4-
(Hydroxyphenyl) butyl acetate, 4,4'-thiobis (2-tert-butyl-5-methylphenol), 4
Dimethyl-hydroxyphthalate, benzyl 4-hydroxybenzoate, methyl 4-hydroxybenzoate, benzyl gallate, stearyl gallate, N, N'-diphenylthiourea, 4,4'-bis (3- (4-methyl Phenylsulfonyl) ureido) diphenylmethane, N- (4-
Methylphenylsulfonyl) -N'-phenylurea, salicylanilide, 5-chlorosalicylanilide, salicylic acid, 3,5-di-tert-butylsalicylic acid,
3,5-di-α-methylbenzylsalicylic acid, 4-
[2 '-(4-methoxyphenoxy) ethyloxy] salicylic acid, 3- (octyloxycarbonylamino) salicylic acid or a metal salt of these salicylic acid derivatives, N
-(4-hydroxyphenyl) -p-toluenesulfonamide, N- (4-hydroxyphenyl) benzenesulfonamide, N- (4-hydroxyphenyl) -1-naphthalenesulfonamide, N- (4-hydroxyphenyl)- 2-naphthalenesulfonamide, N- (4-hydroxynaphthyl) -p-toluenesulfonamide, N-
(4-hydroxynaphthyl) benzenesulfonamide,
N- (4-hydroxynaphthyl) -1-naphthalenesulfonamide, N- (4-hydroxynaphthyl) -2-naphthalenesulfonamide, N- (3-hydroxyphenyl) -p-toluenesulfonamide, N- (3- Hydroxyphenyl) benzenesulfonamide, N- (3-hydroxyphenyl) -1-naphthalenesulfonamide,
N- (3-hydroxyphenyl) -2-naphthalenesulfonamide and the like can be mentioned. These are used singly or as a mixture of two or more, and are used in a proportion of 100 to 700, preferably 150 to 400 parts by weight based on 100 parts by weight of the total amount of the dye precursor.

The heat-sensitive recording layer according to the present invention is prepared by adding a binder, a sensitizer, an oil-absorbing pigment, a surfactant, etc., which are conventionally known in the field of heat-sensitive recording paper, in addition to the above main constituent materials. Applied on top.

Examples of the binder include starches, hydroxyethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, and polymethacrylate. Sodium acrylate, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether, allyl resin, furan resin, ketone resin, oxybenzoyl polyester, polyacetal, polyetheretherketone, polyethersulfone, polyimide, polyamide, polyamideimide, polyaminobismaleimide , Polymethylpentene, polyphenylene oxide, polyphenylene sulfide, polyphenylene Sulfone, polysulfone, polyallylate, polyallyl sulfone, polybutadiene, polycarbonate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyurethane, phenolic resin, urea resin, melamine resin, melamine formalin resin, benzoguanamine resin , Bismaleimide triazine resin, alkyd resin, amino resin, epoxy resin, unsaturated polyester resin, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer , Acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride copolymer Alkali salt of,
An alkali salt or ammonium salt of an ethylene / maleic anhydride copolymer, and other various polyolefin resins are used.

As the sensitizer, those having a melting point of 60 ° C. to 180 ° C. are preferable, and those having a melting point of 80 ° C. to 140 ° C. are more preferably used. Specifically, stearamide, N-hydroxymethyl stearamide,
N-stearylstearic acid amide, ethylene bisstearic acid amide, N-stearylurea, benzyl-2-
Naphthyl ether, m-terphenyl, 4-benzylbiphenyl, 2,2'-bis (4-methoxyphenoxy)
Diethyl ether, α, α′-diphenoxyxylene,
Bis (4-methoxyphenyl) ether, diphenyl adipate, dibenzyl oxalate, di (4-chlorobenzyl) oxalate, dimethyl terephthalate, dibenzyl terephthalate, phenyl benzenesulfonate, bis (4-allyloxyphenyl) Sulfone, 4-
Known sensitizers such as acetylacetophenone, acetoacetic anilide, fatty acid anilide and the like can be mentioned. These compounds can be used alone or in combination of two or more. In order to obtain a sufficient thermal response, the sensitizer preferably accounts for 5 to 50% by weight of the total solid content of the heat-sensitive recording layer.

As the oil absorbing pigment, inorganic and organic pigments such as diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, and urea-formalin resin are used. You.

In addition, higher fatty acid metal salts such as zinc stearate and calcium stearate, and waxes such as paraffin, paraffin oxide, polyethylene, polyethylene oxide, stearic acid amide, caster wax, etc.
In addition, a surfactant such as sodium dioctylsulfosuccinate, a fluorescent dye, and the like can be contained.

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

The support used in the present invention includes paper, various nonwoven fabrics, woven fabrics, plastic films such as polyethylene terephthalate and polypropylene, laminated paper laminated with a synthetic resin such as polyethylene and polypropylene, synthetic paper, and aluminum. Metal foil, glass, or the like, or a composite sheet combining these can be used arbitrarily according to the purpose, but is not limited thereto. These may be opaque, transparent, or translucent. In order to make the background appear white or another specific color, a white pigment, a colored dye or a bubble may be contained in the support or on the surface.

In order to increase the sensitivity of the heat-sensitive recording material and to prevent printing residue, these supports are provided with oil absorbing pigments, heat-insulating hollow particles, air capsules containing air therein, and the like in advance. A heat-sensitive coated paper coated so as to have a thickness of up to 30 g / m ² is particularly effective as a support. If the coating amount is less than this range, the effect of improving the sensitivity is not sufficient, and if it is more than this range, it may be difficult to obtain a uniform smooth surface. In addition, a magnetic recording material layer may be applied to the back surface of the support in advance, or an adhesive layer may be applied to the back surface after applying the heat-sensitive recording layer to process the heat-sensitive label.

In the present invention, a protective layer may be provided on the heat-sensitive recording layer in order to improve image storability. As a material of the protective layer, a film-forming material such as a water-soluble polymer and latex is formed as a main component. For example, starches, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol,
Modified polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyacrylate, polymethacrylate, sodium polyacrylate, polyethylene terephthalate, polybutylene terephthalate, chlorinated polyether, allyl resin, furan resin, ketone resin, oxybenzoyl Polyester, polyacetal, polyetheretherketone, polyethersulfone, polyimide, polyamide, polyamideimide, polyaminobismaleimide, polymethylpentene, polyphenylene oxide, polyphenylene sulfide, polyphenylene sulfone, polysulfone, polyarylate, polyallyl sulfone, polybutadiene, polycarbonate, Polyethylene, polypropylene, polystyrene, polyvinyl chloride,
Polyvinylidene chloride, polyvinyl acetate, polyurethane,
Phenolic resin, urea resin, melamine resin, melamine formalin resin, benzoguanamine resin, bismaleimide triazine resin, alkyd resin, amino resin, epoxy resin, unsaturated polyester resin, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer,
Methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride copolymer Alkali salts of polymers, alkali salts or ammonium salts of ethylene / maleic anhydride copolymers, and various other polyolefin-based resins, and the like, various hardening agents for imparting water resistance, crosslinking agents, A single layer or two or more layers are laminated on the heat-sensitive recording layer by adding various pigments and the like for improving the writability and the running property.

The method for forming each layer constituting the heat-sensitive recording material of the present invention on a support is not particularly limited.
It can be formed by a conventional method. For example, air knife coater, various blade coater, various bar coater, coating equipment such as various curtain coater, lithographic,
Various printing methods such as letterpress, intaglio, flexo, gravure, and screen can be used.

[0045]

The present invention will be described in more detail with reference to the following examples. The following parts are parts by weight, and% is% by weight.
And a * and b * values represent color difference values defined by JIS-Z8730 according to the measurement method defined by JIS-Z8722.

[1] Preparation of Dispersion Particles of Electron Donor Dye Precursor for Low-Temperature Color Development (a) Preparation of Dispersion Particles of Dye Precursor for Red Low-Temperature Color Development 3-Diethylamino-7 which is an electron-donation dye precursor for red color development 3 parts of chlorofluorane and 12 parts of a 2.5% aqueous polyvinyl alcohol solution were pulverized with a ball mill to obtain a low-temperature coloring dye precursor dispersion having a volume average particle diameter of 1 μm.

(B) Preparation of Dispersed Particles of Dye Precursor for Blue Low-Temperature Color Development Three parts of 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, which is a blue-colored electron-donating dye precursor, is prepared. 2.5% polyvinyl alcohol aqueous solution 1
The mixture was pulverized together with 2 parts by a ball mill to obtain a low-temperature color-forming dye precursor dispersion having a volume average particle size of 1 μm.

(C) Preparation of Dye Precursor Dispersed Particles for Yellow Low-Temperature Color Development 2,2-bis (4- (2- (4-diethylaminophenyl) quinazolyl) oxyphenyl) which is a yellow-colored electron-donating dye precursor 3 parts of propane are ground with a ball mill together with 12 parts of a 2.5% aqueous polyvinyl alcohol solution,
A low-temperature color-forming dye precursor dispersion having a volume average particle size of 1 μm was obtained.

[2] Preparation of Dye Precursor for High-Temperature Color Forming Provided with Color Controlling Layer on Surface (A) Preparation of Dye Precursor for Black High-Temperature Color Development 3-Dibutylamino- 5 parts of 6-methyl-7-anilinofluoran
The mixture was pulverized with a ball mill together with 85 parts of a 5% aqueous polyvinyl alcohol solution to obtain a dye precursor dispersion having a volume average particle size of 1 μm. Next, this dispersion was transferred to a polymerization vessel, and 4 parts of methyl methacrylate and 1 part of trimethylolpropane trimethacrylate were added, and the temperature was raised to 70 ° C. while stirring. To this, 5 parts of a 1% aqueous solution of potassium persulfate as a polymerization initiator was added, and the mixture was reacted for 6 hours while stirring was continued. Then, this was cooled to room temperature to obtain a dispersion liquid of a high-temperature coloring dye precursor having a coloring control layer on the surface.

(B) Preparation of Dye Precursor for High-Temperature Green Coloring In (A), 5 parts of 3-dibutylamino-6-methyl-7-anilinofluoran, which is an electron-donating dye precursor for black coloring, 3- (N-ethyl-Np-tolyl) amino-7- (N
-Phenyl-N-methyl) aminofluorane was obtained in the same manner as in (A) except that the dispersion was changed to 5 parts, and a dispersion of the dye precursor for high-temperature color development provided with a color control layer on the surface was obtained.

(C) Preparation of Dye Precursor for Blue High-Temperature Coloring In (A), 5 parts of 3-dibutylamino-6-methyl-7-anilinofluoran, which is a black-colored electron-donating dye precursor, The color development was adjusted on the surface in the same manner as in (A) except that 5 parts of 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, which is a blue-colored electron-donating dye precursor, was changed. A dispersion of a high-temperature coloring dye precursor having a layer was obtained.

(D) Preparation of Dye Precursor for High-Temperature Red Coloring In (A), 5 parts of 3-dibutylamino-6-methyl-7-anilinofluoran, which is a black-coloring electron-donating dye precursor, A high-temperature coloring dye precursor having a coloring control layer on the surface in the same manner as (A) except that 5 parts of 3-diethylamino-7-chlorofluorane, which is a red-coloring electron-donating dye precursor, is changed. Was obtained.

(E) Preparation of Dye Precursor for Yellow High Temperature Color Formation In (A), 5 parts of 3-dibutylamino-6-methyl-7-anilinofluoran, which is an electron-donating dye precursor for black coloring, In the same manner as in (A), except that 5 parts of 2,2-bis (4- (2- (4-diethylaminophenyl) quinazolyl) oxyphenyl) propane, which is a yellow-colored electron-donating dye precursor, was used, A dispersion of a high-temperature coloring dye precursor having a coloring control layer on the surface was obtained.

(F) Preparation of Dye Precursor for Highly Sensitive Green High-Temperature Coloring In (A), 5 parts of 3-dibutylamino-6-methyl-7-anilinofluoran, which is an electron-donating dye precursor for black coloring, With 3- (N-ethyl-Np-tolyl) amino-7- (N
-Phenyl-N-methyl) aminofluorane, except that methyl methacrylate 4 parts and trimethylolpropane trimethacrylate 1 part were changed to methyl methacrylate 4.2 parts and trimethylolpropane trimethacrylate 0.8 part In the same manner as in (A), a dispersion of a high-temperature coloring dye precursor having a surface on which a coloring control layer was provided was obtained.

(G) Preparation of Dye Precursor for Highly Sensitive Yellow and High-Temperature Coloring In (A), 5 parts of 3-dibutylamino-6-methyl-7-anilinofluoran, which is an electron-donating dye precursor for black coloring, Was added to 5 parts of 2,2-bis (4- (2- (4-diethylaminophenyl) quinazolyl) oxyphenyl) propane which is a yellow-colored electron-donating dye precursor, 4 parts of methyl methacrylate and trimethylolpropanetriene. Dye precursor for high-temperature color development provided with a color development control layer on the surface in the same manner as in (A) except that 1 part of methacrylate was changed to 4.2 parts of methyl methacrylate and 0.8 part of trimethylolpropane trimethacrylate. Was obtained.

[3] Preparation of a mother liquor for coating a multicolor heat-sensitive recording layer containing an electron-accepting developer: 8 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone, an electron-accepting developer, was added to 2% polyvinyl chloride. The mixture was ground with a ball mill together with 24 parts of an alcohol aqueous solution to obtain 32 parts of an electron-accepting compound dispersion having a volume average particle diameter of 1 μm.
Further, 8 parts of 2-benzyloxynaphthalene were pulverized with a ball mill together with 24 parts of a 2% aqueous solution of polyvinyl alcohol to obtain 32 parts of a 2-benzyloxynaphthalene dispersion having a volume average particle diameter of 1 μm. Further, 5 parts of calcium carbonate (Univar 70 manufactured by Shiroishi Kogyo) was pulverized with a homogenizer together with 10 parts of a 2% aqueous sodium hexametaphosphate solution,
15 parts of a calcium carbonate dispersion having a volume average particle size of 1 μm were obtained. The three dispersions were mixed to prepare a mother liquor for coating the multicolor heat-sensitive recording layer.

[4] Preparation of support for multicolor heat-sensitive coating A coating liquid composed of 100 parts of calcined kaolin, 24 parts of a 50% styrene-butadiene-based latex aqueous dispersion, and 200 parts of water was coated on a basis weight of 50 g / m 2. ² high quality paper was coated so as to have a solid content of 5 g / m ² and dried to prepare a heat-sensitive coating support.

[5] Preparation of multicolor heat-sensitive recording material 15 parts of the low-temperature coloring dye precursor dispersion prepared in [1] and the high-temperature coloring dye precursor having a surface provided with a coloring control layer prepared in [2] Body dispersions (A) to (G) alone or
A multicolor heat-sensitive recording layer coating solution prepared by adjusting 100 parts of the two kinds of equal mixed liquids and 79 parts of the multicolor heat-sensitive recording layer coating mother liquor prepared in [3] according to the combination shown in Table 1 was used in [4]. After coating and drying on the multicolor heat-sensitive coating support prepared in the above, so that the solid coating amount is 7 g / m ² , the coating surface has a Beck smoothness of 4
The multicolor heat-sensitive recording materials of Examples 1 to 8 and Comparative Examples 1 to 6 were produced by performing a calendering treatment so as to reach 00 to 500 seconds.

[0059]

[Table 1] In [2] of Examples 1 to 8 in the table, the compounding ratio of the two high-temperature coloring dye precursors is 50:50. In Examples 3 and 7, M indicates a high-sensitivity color-developing layer.

Test 1 Color Test of Multicolor Thermosensitive Recording Material The metal blocks heated at 90 ° C. and 130 ° C. were applied to the multicolor thermosensitive recording materials of Examples 1 to 8 and the multicolor thermosensitive recording materials of Comparative Examples 1 to 6. Press for 2 seconds to develop low-temperature color at 90 ° C, 1
The color was developed at 30 ° C. at a high temperature. A density meter (Macbeth RD918; GRETA)
G MACBETH), and the position of the filter hole was measured in black. In addition, a * of the high-temperature coloring portion (black),
The b * value was measured using a SpectroEye manufactured by Macbeth.
Further, the color tone of the low-temperature part and the color tone of the high-temperature part were visually observed. The results are shown in Tables 2 to 4.

Test 2 Printing Test of Multicolor Thermosensitive Recording Material The TDK print head (LH440) was applied to the multicolor thermosensitive recording materials of Examples 1 to 8 and the multicolor thermosensitive recording materials of Comparative Examples 1 to 6.
9) Okura Electric Thermal Facsimile Printing Tester (TH
-PMD), continuous application of low-energy printing of the character "H" at an applied voltage of 1.0 millisecond at an applied voltage of 20 volts and high-energy printing of the character "H" at an applied pulse of 2.0 milliseconds Printing was performed. Since color bleeding is clearly expressed by the color tone of each printed character, "black H character tone" was visually observed. Also, the vividness of the color separation between the low-energy printed characters and the high-energy printed characters was visually observed. The results are shown in Tables 2 to 4 under the items of "black H character tone" and "color separation".

[0062]

[Table 2]

In Table 2, in the item of high-temperature part color tone, ◎ indicates clear black, は indicates slightly brownish black, Δ indicates reddish-brown black, and × indicates purple.

In the item of black H character tone in Table 2, ◎ indicates that the character “H” is bright black,
Indicates that the letter “H” is black, Δ indicates that the letter “H” appears slightly brownish black, and X indicates that the letter “H” appears brown or purple.

Further, in the color separation item of Table 2, ◎ indicates a state in which red and black “H” characters are arranged and the red and black color separation is very clear. In the state where the color separation is clear, Δ indicates a state where the color separation between red and black is slightly indistinct, and x indicates a state where the color separation between red and black is unclear.

From Table 2, the following can be said for the case of a red-black two-color heat-sensitive recording material. That is, in the high-temperature part, the combined use of the two-color dye precursor is higher than that of the single-color part in the high-temperature part color tone and black H.
Excellent in character color tone and color separation (comparison between Examples 1-4 and Comparative Examples 1-3). It is better to use a dye precursor which is a complementary color of the low-temperature part in the high-temperature part (comparison between Example 2 and Example 4). When the color control layer of the high temperature part complementary color dye precursor is set to the high sensitivity side, the color bleeding (black H character color tone) is improved (Example 2).
And Example 3). It is better to use a black color as the high-temperature color (comparison between Example 1 and Example 2).

[0067]

[Table 3]

In Table 3, in the high-temperature part color tone, は indicates clear black, は indicates slightly dark blue black, Δ indicates blueish black, and × indicates purple.

In the item of the black H character tone of Table 3, ◎ indicates that the character “H” is black, and ○ indicates “H”.
Ｈ is “H” in the state where the character is dark blue black
Indicates that the letter “H” looks dark blue, and “x” indicates that the letter “H” looks purple.

Further, in Table 3, the color separation item ◎ indicates that the red and black “H” characters are arranged and the blue and black color separation is very clear, and 、 indicates the blue and black color separation. In the state where the color separation is clear, x indicates a state where the color separation between blue and black is unclear.

From Table 3, the following can be said even when the low-temperature color is dark as in the case of the blue-black two-color heat-sensitive recording material. That is, in the high temperature part, the combined use of the two color tone dye precursors is superior to the one color tone in the high temperature part color tone, the black H character color tone, and the color separation (comparison between Examples 5 to 7 and Comparative Examples 4 and 5). It is better to use a dye precursor that is a complementary color of the low-temperature part in the high-temperature part (comparison between Example 6 and Comparative Example 4). When the color control layer of the high temperature part complementary color dye precursor is set to the high sensitivity side, color bleeding (black H character color tone) is improved (comparison between Example 6 and Example 7). It is better to use a black color as the high-temperature color (comparison between Example 5 and Example 6).

[0072]

[Table 4]

In Table 4, in the item of high-temperature part color tone, ○ indicates clear black, and X indicates yellowish black.

In the item of black H character tone of Table 4, .largecircle. Indicates that the character "H" is black, and X indicates "H".
This shows a state in which the yellow blur around the character is very noticeable.

From Table 4, it can be seen that the high-temperature portion is more black than the single color.
It can be seen that the additional use of the complementary color (blue) of the low-temperature color (yellow) is more effective for color bleeding (black H character tone) even when the sensitivity of the color-adjusting layer in the high-temperature portion is the same.

[0076]

As described above, according to the present invention, at least two types of dye precursors are wrapped in the color control layer on the high temperature side, and a dye precursor which is a complementary color of a low temperature color is used on the high temperature side. By doing so, color separation is improved by controlling color tone and improving color blur, and furthermore, by making the color control layer of this complementary color dye precursor more sensitive than others, remarkable color blur is improved, and the result is As a result, it is possible to provide a multicolor heat-sensitive recording material having good color separation and high resolution of high-temperature printed characters.

Claims (6)

[Claims] 1. A heat-sensitive recording layer comprising, on a support, three or more electron-donating dye precursors that develop colors different from each other, and an electron-accepting color developer that develops the dye precursor upon heating. Wherein the dye precursor comprises 1) one or more low-temperature coloring dye precursor dispersed particles, and 2) a color formation control layer obtained by addition polymerization of a vinyl monomer. A multicolor heat-sensitive recording material comprising two or more high-temperature coloring dye precursors on each surface. 2. The multicolor heat-sensitive recording according to claim 1, wherein the high-temperature coloring dye precursor having the color control layer on the surface is a dye precursor that is complementary to the low-temperature coloring dye precursor. material. 3. The color control layer formed on the surface of the dye precursor which is complementary to the low temperature color dye precursor has higher sensitivity than the color control layer formed on another dye precursor. 3. The multicolor heat-sensitive recording material according to claim 2, wherein: 4. The dye precursor according to claim 1, wherein one of the high-temperature coloring dye precursors having the coloring control layer on the surface is a dye precursor that develops a black color. Multicolor thermal recording material. 5. The multicolor heat-sensitive recording material according to claim 4, wherein the low-temperature coloring dye precursor is a dye precursor that develops a reddish color. 6. The multicolor heat-sensitive recording material according to claim 4, wherein the low-temperature coloring dye precursor is a dye precursor that develops a bluish color.