JP2001113827A - Multicolor heat-sensitive recording body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multicolor heat-sensitive recording body obtaining a recorded image of high recording density and the sharp tone and keeping the clear color separating properties even under the high temperature atmosphere. SOLUTION: At least one or more high temperature coloring layers containing a dye precursor and an organic developer reacted with the dye precursor under heating and at least one or more low temperature coloring layers coloring a color tone different from that of the high temperature coloring layer are formed successively on a substrate of a multicolor heat-sensitive recording body, and a 3- [(phenylamino)carbonyl]amino)benzene sulfoneamide as the organic developer for the high temperature coloring layer is contained in the multicolor heat-sensitive recording body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor heat-sensitive recording material, and more particularly to a multicolor heat-sensitive recording material having a plurality of color-forming layers that develop different colors depending on the heating conditions from a thermal head. is there.

[0002]

2. Description of the Related Art In general, a heat-sensitive recording layer mainly comprising a colorless or light-colored electron-donating dye precursor (hereinafter referred to as a dye precursor) and a developer which reacts with the dye precursor when heated to form a color is provided. The heat-sensitive recording medium has
No. pp. 139, and widely used. In order to perform recording on this thermosensitive recording medium, a thermal printer or the like having a built-in thermal head is used.However, such a thermosensitive recording method has less noise at the time of recording as compared with other recording methods that have been practically used conventionally. With no development and fixing, maintenance-free, relatively inexpensive and compact equipment, and very clear color development, the facsimile and computer fields Widely used for various measuring instruments and labels. The quality required for the heat-sensitive recording medium has been diversified with the expansion of its use, and examples thereof include high sensitivity, image stabilization, and multicolor recording images. In particular, multi-color recording images have the advantage that characters or graphics to be emphasized can be clearly displayed because they can be recorded in a color tone different from other portions.

As a multicolor heat-sensitive recording material, for example, it is known that a plurality of color-forming layers, each of which develops a different color tone, are provided on a support, and a recording image is formed by utilizing a difference in heating temperature or heat energy. Oil. These have a configuration in which a high-temperature coloring layer and a low-temperature coloring layer that develops a color at a lower temperature or thermal energy than the high-temperature coloring layer are sequentially laminated,
It can be broadly divided into two methods, a decoloring type and an adding color type.

[0004] The color development mechanism in the decolorable type thermosensitive recording medium is described in, for example, Japanese Patent Publication No. 50-17865 and Japanese Patent Publication No. 57-14.
As disclosed in JP-A-320-320 and JP-A-2-80287, only the low-temperature coloring layer develops color by heating at low temperature, and has a decoloring effect on the coloring system of the low-temperature coloring layer upon heating at high temperature. The decoloring agent acts and only the high-temperature coloring layer develops color. This method has an advantage that the color tone can be freely selected, but it is necessary to add a large amount of the decoloring agent in order to obtain a sufficient decoloring effect on the low-temperature coloring layer. Such a large amount of the decoloring agent causes problems such as a decrease in the preservability of the recorded image and a reduction in the recording sensitivity because a large amount of heat energy is consumed for melting the decoloring agent.

On the other hand, examples of a color-added thermal recording medium are disclosed in JP-B-49-27708 and JP-B-51-19989.
And JP-A-51-146239 disclose a method of stacking two color-forming layers that develop colors with different colors and applying different amounts of heat to obtain distinguishable two-color images. In these methods, the upper low-temperature coloring layer develops color by heating at low temperature, and the lower high-temperature coloring layer also develops color by heating at high temperature to form both upper and lower coloring layers. In order to obtain the following, it was essential that the lower layer be substantially black. In addition, since the lower black image is obtained by mixing colors with the upper color developing system, the color of the upper color developing layer is slightly overlaid on the black image, and the difference between the two color tones is unclear, or on the dashboard of the car. When exposed to such a high-temperature atmosphere, there is a problem that the high-temperature coloring layer develops a color and the low-temperature coloring tone becomes fogged or becomes black. Also, Japanese Patent Application Laid-Open No. 4-3
Japanese Patent No. 29186 describes that a specific coloring agent is contained in a high-temperature coloring layer to solve the problem that the high-temperature coloring layer develops color at the time of low-temperature heating to cause color turbidity. The clarity of the low-temperature color tone and the stability of the ground color were still insufficient.

[0006]

Therefore, according to the present invention, clear color-formed images can be obtained in the low-temperature color-forming layer and the high-temperature color-forming layer, respectively, and the low-temperature color-formed image is fogged (color mixture) even in a high-temperature atmosphere by the color tone of the high-temperature color-forming layer. An object of the present invention is to provide a multicolor heat-sensitive recording medium which is excellent in color separation property without any problem.

[0007]

According to the present invention, in order to achieve the above object, the present invention comprises, on a support, a dye precursor and an organic developer which reacts with the dye precursor under heating to form a color. A high-temperature coloring layer, and a low-temperature coloring layer that exhibits a color tone different from that of the high-temperature coloring layer and that develops a color at a temperature lower than the temperature at which the high-temperature coloring layer develops. As 3-{[(phenylamino)
[Carbonyl] amino} benzenesulfonamide.

The multicolor heat-sensitive recording material of the present invention uses an aminobenzenesulfonamide compound represented by the following structural formula as an organic developer contained in the high-temperature coloring layer.

[0009]

Embedded image

Further, according to the present invention, the low-temperature coloring layer which exhibits a color tone different from that of the high-temperature coloring layer and develops at a temperature lower than the temperature at which the high-temperature coloring layer develops is not limited to a single layer. No, coloring layer that develops color at lower temperature,
By sequentially laminating the color images, it is possible to obtain a color image having a plurality of color tones.

A multicolor heat-sensitive recording medium that develops a color tone of two or more colors is very susceptible to changes in the temperature environment as compared with a normal heat-sensitive recording medium because of its coloring mechanism utilizing a difference in heating temperature or heat energy. It can be said that. In the case of a low-temperature color tone formed by low-temperature heating (low-energy printing), it is important to minimize the influence of color development of the high-temperature color-forming layer in order to maintain the sharpness of the color tone. To do this,
It is considered effective to increase the melting point of the color developer used in the high-temperature coloring layer to suppress the coloring of a part of the high-temperature coloring layer during heating at a low temperature.

However, even if a developer having a high melting point is simply used, when the high-temperature coloring layer and the low-temperature coloring layer are laminated, mixing occurs between the two layers and the melting point is lowered. As compared with the case where the layers are separately provided on a support, the ground color stability against heat is remarkably deteriorated and the whiteness is reduced. For example, when 2,4'-dihydroxydiphenylsulfone or 4,4'-dihydroxydiphenylsulfone, which is conventionally known as a developer having a relatively high melting point, is used, the color development at an environment of about 60.degree. And the ground color stability is not sufficient.

On the other hand, the present inventors have found that the specific aminobenzenesulfonamide compound contained in the high-temperature color-forming layer prevents ground color development in a high-temperature environment, and also allows the high-temperature color-forming layer for a low-temperature color image. The present inventors have found that fogging due to the above can be improved, and have accomplished the present invention.
Although the reason why the excellent action and effect are obtained in the present invention is not clear, the specific aminobenzenesulfonamide compound is a non-phenol-based color developer, and a general phenol-based color developer contained in a low-temperature color-forming layer. Is structurally different from the above, so that the compatibility between the molecules is low, and it is considered that the melting point does not decrease even when mixed with another developer. In addition, since the specific aminobenzenesulfonamide compound specifically has high heat stability, it does not develop color even in a high-temperature environment, and it is considered that the color tone of a low-temperature color image can be kept clear. Can be

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the multicolor thermosensitive recording medium of the present invention, the color tone of each color forming layer is adjusted by selecting a leuco dye as a dye precursor. In the case of a two-color thermosensitive recording medium, for example, the low-temperature coloring layer is a single-color system (for example, blue, red, yellow, etc.) having a single absorption peak when coloring, and the high-temperature coloring layer is different. It is preferable to use a multicolor system (for example, green, black, etc.) having a plurality of absorption peaks when the color is developed in a mixed color tone because a clear color tone can be easily obtained and the color separation property is good.

When a black leuco dye is used in the high-temperature coloring layer of the present invention, among others, 3-diethylamino-7- (o
-Chloroanilino) fluoran, 3-diethylamino-
6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-7- (o-chloroanilino) fluoran,
3-di-n-pentylamino-6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino)
-6-Methyl-7-anilinofluoran and 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran are 3-{[(phenylamino) When used in combination with [carbonyl] amino} benzenesulfonamide, it is preferable because it does not develop color at the time of heating at low temperature, does not cause fogging to the low-temperature coloring image, and can obtain an extremely clear black color image even at the time of heating at high temperature. . Further, among these, 3-diethylamino-7
-(O-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino) fluoran, and 3
-(N-ethyl-p-toluidino) -6-methyl-7
-The use of anilinofluorane is particularly preferred, since a thermosensitive recording material having very little ground color when stored under high-temperature conditions can be obtained.

In addition to the above, as the leuco dye used in the heat-sensitive recording medium of the present invention, any of those known in the field of conventional pressure-sensitive or heat-sensitive recording paper can be used, and there is no particular limitation. Preferred are a triphenylmethane-based compound, a fluoran-based compound, a fluorene-based compound, a divinyl-based compound, and the like. Specific examples of typical basic colorless dyes are shown below. These dye precursors may be used alone or in combination of two or more.

<Triphenylmethane leuco dye> 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide [also known as crystal violet lactone] 3,3-bis (p-dimethylaminophenyl) phthalide [ Malachite green lactone] <Fluoran leuco dye> 3-Diethylamino-6-methylfluoran 3-Diethylamino-6-methyl-7-anilinofluoran 3-Diethylamino-6-methyl-7- (o, p-dimethyl Anilino) fluorane 3-diethylamino-6-methyl-7-chlorofluoran 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-6-methyl-7- (m- Methylanilino) fluoran 3-diethylamino-6-methyl Le-7- (o-chloroanilino) fluoran 3-diethylamino-6-methyl-7- (p-chloroanilino) fluoran 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluoran 3-diethylamino-6 Methyl-7-n-octylanilinofluoran 3-diethylamino-6-methyl-7-n-octylaminofluoran 3-diethylamino-6-methyl-7-benzylanilinofluoran 3-diethylamino-6-methyl- 7-dibenzylanilinofluoran 3-diethylamino-6-chloro-7-methylfluoran 3-diethylamino-6-chloro-7-anilinofluoran 3-diethylamino-6-chloro-7-p-methylanilino Fluoran 3-diethylamino-6-ethoxyethyl-7-anilinofur Oran 3-diethylamino-7-methylfluorane 3-diethylamino-7-dibenzylaminofluoran 3-diethylamino-6,8-dimethylfluoran 3-diethylamino-7-chlorofluorane 3-diethylamino-7- (m- Trifluoromethylanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-7- (p-chloroanilino) fluoran 3-diethylamino-7- (o-fluoroanilino) fluoran 3-diethylamino-benzo [A] Fluoran 3-diethylamino-benzo [c] fluoran

3-dibutylamino-6-methyl-fluoran 3-dibutylamino-6-methyl-7-anilinofluoran 3-dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3 -Dibutylamino-6-methyl-7- (o-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (p-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (o-fluoroanilino ) Fluorane 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-Dibutylamino-6-methyl-chlorofluorane 3-Dibutylamino-6-methyl-7-bromofluoran 3 -Dibutylamino-6-ethoxyethyl-7-anilinofluoran 3-dibutylamino-6-chloro -7-anilinofluoran 3-dibutylamino-6-methyl-7-p-methylanilinofluoran 3-dibutylamino-7- (o-chloroanilino) fluoran 3-dibutylamino-7- (o-fluoroani Rino) fluorane 3-di-n-pentylamino-6-methyl-7-anilinofluoran 3-di-n-pentylamino-6-methyl-7- (p-
Chloroanilino) fluorane 3-di-n-pentylamino-7- (m-trifluoromethylanilino) fluoran 3-di-n-pentylamino-6-chloro-7-anilinofluoran 3-di-n-pentyl Amino-7- (p-chloroanilino) fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl-7-anilinofluoran 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluoran 3- (N-methyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-ethyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-ethyl-N-xylamino) -6-methyl-
7- (p-chloroanilino) fluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-chloro-7-anilino Fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofluoran

3- (Np-tolyl-N-ethylamino) -7- (N-phenylmethyl-N-methyl) fluoran 3- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran 3-N-ethyl-N-isoamylamino-benzo [a]
Fluoran 3-N-ethyl-Np-methylphenylamino-7-
Methylfluoran 3-cyclohexylamino-6-chlorofluoran 2- (4-oxahexyl) -3-dimethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-diethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-dipropylamino-
6-methyl-7-anilinofluoran 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluoran 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2 -Chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-amino-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2- Benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2-hydroxy-6-p- (p-phenylaminophenyl) aminoanilinofluoran 3-methyl-6-p- (p-dimethyl Aminophenyl)
Aminoanilinofluoran 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluoran 2,4-dimethyl- 6-[(4-dimethylamino) anilino] -fluoran

<Fluorene Leuco Dye>3,6,6'-Tris (dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-Tris (diethylamino) spiro [fluorene-9,3 '-Phthalide] <Divinyl leuco dye> 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrabromophthalide 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrachlorophthalide 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide 3,3- Bis- [1- (4-methoxyphenyl) -1-
(4-pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-tetrachlorophthalide <Others> 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) ) -4-Azaphthalide 3,3-bis (1-ethyl-2-methylindole-3
-Yl) phthalide 3,3-bis (1-n-butyl-2-methylindol-3-yl) phthalide 3,6-bis (diethylamino) fluoran-γ- (3
'-Nitro) anilinolactam 3,6-bis (diethylamino) fluoran-γ- (4
'-Nitro) anilinolactam 1,1-bis- [2', 2 ', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-dinitrileethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2-
β-naphthoylethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-Diacetylethane bis- [2,2,2 ', 2'-tetrakis- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

In the present invention, examples of the developer contained in the low-temperature color-forming layer include, for example, JP-A-3-207688,
Bisphenol A, 4-hydroxybenzoic acid ester, 4-hydroxyphthalic acid diester, phthalic acid monoester described in JP-A-5-24366, etc.
Bis- (hydroxyphenyl) sulfides, 4-hydroxyphenylarylsulfones, 4-hydroxyphenylarylsulfonates, 1,3-di [2- (hydroxyphenyl) -2-propyl] -benzenes,
-Hydroxybenzoyloxybenzoic acid esters, bisphenolsulfones, aminobenzenesulfonamide derivatives described in JP-A-8-59603, International Publication WO97
/ 16420 is exemplified. These developers are appropriately selected depending on desired recording sensitivity and other characteristics. Specific examples of typical known color developers are shown below, but the present invention is not particularly limited thereto.

<Bisphenol A>4,4'-isopropylidene diphenol (also known as bisphenol A) 4,4'-cyclohexylidene diphenol p, p '-(1-methyl-normalhexylidene) diphenol 1, 7-di (hydroxyphenylthio) -3,5-dioxaheptane <4-hydroxybenzoates> Benzyl 4-hydroxybenzoate Ethyl 4-hydroxybenzoate Propyl 4-hydroxybenzoate 4-Isopropyl benzoate 4 -Butyl hydroxybenzoate 4-Isobutyl 4-hydroxybenzoate Methylbenzyl 4-hydroxybenzoate <Diesters of 4-hydroxyphthalic acid> Dimethyl 4-hydroxyphthalate 4-Diisopropyl 4-hydroxyphthalate 4-Dibenzyl 4-hydroxyphthalate 4-hydro Dihexyl phthalate <Monoesters of phthalic acid> Monobenzyl phthalate Monocyclohexyl phthalate Monophenyl phthalate Monomethyl phthalate Monoethyl phthalate Monoethyl phenyl phthalate Monopropyl benzyl phthalate Monohalogen benzyl phthalate Phthalic acid Monoethoxybenzyl ester

<Bis- (hydroxyphenyl) sulfides> Bis- (4-hydroxy-3-tert-butyl-6-
Methylphenyl) sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide bis- (4-hydroxy-2-methyl-5-ethylphenyl) sulfide bis- (4-hydroxy-2-methyl-5-isopropylphenyl) sulfide bis- (4-hydroxy-2,3-dimethylphenyl)
Sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide bis- (4-hydroxy-2,5-diisopropylphenyl) sulfide bis- (4-hydroxy-2,3,6-trimethylphenyl) sulfide bis- (2,4,5-trihydroxyphenyl) sulfide bis- ( 4-hydroxy-2-cyclohexyl-5-methylphenyl) sulfide bis- (2,3,4-trihydroxyphenyl) sulfide bis- (4,5-dihydroxy-2-tert-butylphenyl) sulfide bis- (4- Hydroxy-2,5-diphenylphenyl) sulfide bis- (4-hydroxy-2-tert-octyl-5)
-Methylphenyl) sulfide <4-hydroxyphenylarylsulfones>4-hydroxy-4'-isopropoxydiphenylsulfone4-hydroxy-4'-n-propoxydiphenylsulfone4-hydroxy-4'-n-butyloxydiphenylsulfone<4-hydroxyphenylarylsulfonates> 4-hydroxyphenylbenzenesulfonate 4-hydroxyphenyl-p-tolylsulfonate 4-hydroxyphenylmethylenesulfonate 4-hydroxyphenyl-p-chlorobenzenesulfonate 4-hydroxyphenyl- p-tert-butylbenzenesulfonate 4-hydroxyphenyl-p-isopropoxybenzenesulfonate 4-hydroxyphenyl-1'-naphthalenesulfonate 4-hydroxy Cyphenyl-2'-naphthalene sulfonate

<1,3-di [2- (hydroxyphenyl) -2-propyl] benzenes> 1,3-di [2- (4-hydroxyphenyl) -2-propyl] benzene 1,3-di [ 2- (4-hydroxy-3-alkylphenyl) -2-propyl] benzene 1,3-di [2- (2,4-dihydroxyphenyl)-
2-propyl] benzene 1,3-di [2- (2-hydroxy-5-methylphenyl) -2-propyl] benzene <resorcinols> 1,3-dihydroxy-6 (α, α-dimethylbenzyl) -benzene <4-Hydroxybenzoyloxybenzoate> Benzyl 4-hydroxybenzoyloxybenzoate Methyl 4-hydroxybenzoyloxybenzoate Ethyl 4-hydroxybenzoyloxybenzoate Propyl 4-hydroxybenzoyloxybenzoate Butyl 4-hydroxybenzoyloxybenzoate Isopropyl 4-hydroxybenzoyloxybenzoate tert-butyl 4-hydroxybenzoyloxybenzoate hexyl 4-hydroxybenzoyloxybenzoate octyl 4-hydroxybenzoyloxybenzoate 4-h Roxybenzoyloxy nonyl 4-hydroxybenzoyloxybenzoate cyclohexyl 4-hydroxybenzoyloxybenzoate β-phenethyl 4-hydroxybenzoyloxybenzoate phenyl 4-hydroxybenzoyloxybenzoate α-naphthyl 4-hydroxybenzoyloxybenzoate β -Naphthyl sec-butyl 4-hydroxybenzoyloxybenzoate

<Bisphenolsulfones (I)> bis- (3-1-butyl-4-hydroxy-6-methylphenyl) sulfone bis- (3-ethyl-4-hydroxyphenyl) sulfone bis- (3-propyl-) 4-hydroxyphenyl) sulfone bis- (3-methyl-4-hydroxyphenyl) sulfone bis- (2-isopropyl-4-hydroxyphenyl)
Sulfone bis- (2-ethyl-4-hydroxyphenyl) sulfone bis- (3-chloro-4-hydroxyphenyl) sulfone bis- (2,3-dimethyl-4-hydroxyphenyl)
Sulfone bis- (2,5-dimethyl-4-hydroxyphenyl)
Sulfone bis- (3-methoxy-4-hydroxyphenyl) sulfone 4-hydroxyphenyl-2'-ethyl-4'-hydroxyphenylsulfone 4-hydroxyphenyl-2'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-secbutyl-4'-
Hydroxyphenylsulfone 3-chloro-4-hydroxyphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-aminophenyl -4'-hydroxyphenylsulfone 2-hydroxy-5-t-isopropylphenyl-4 '
-Hydroxyphenylsulfone 2-hydroxy-5-t-octylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-chloro-4'-hydroxyphenylsulfone 2-hydroxy-5-t -Butylphenyl-3'-methyl-4'-hydroxyphenylsulfone 2-hydroxy-5-tert-butylphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-tert-butylphenyl-2 '-Methyl-4'-hydroxyphenylsulfone

<Bisphenol sulfones (II)>4,4'-sulfonyldiphenol2,4'-sulfonyldiphenol3,3'-dichloro-4,4'-sulfonyldiphenol3,3'-dibromo-4 , 4'-Sulfonyldiphenol 3,3 ', 5,5'-Tetrabromo-4,4'-sulfonyldiphenol 3,3'-Diamino-4,4'-sulfonyldiphenol <Others> p-tert-butylphenol 2,4-dihydroxybenzophenone novolak type phenol resin 4-hydroxyacetophenone p-phenylphenol benzyl-4-hydroxyphenylacetate p-benzylphenol 4,4′-bis (p-tolylsulfonylaminocarbonylamino) diphenylmethane 4,4′- Bis (phenylaminothioca Boniruamino) diphenyl sulfide

In addition to these, metal chelate-type coloring components such as higher fatty acid metal double salts and polyvalent hydroxy aromatic compounds described in JP-A-10-258577 can also be used as image forming materials. These chelate coloring components are used alone or in combination with the above-mentioned leuco dye and developer.

In the present invention, the recording sensitivity can be adjusted by adding a conventionally known sensitizer to each color-forming layer as long as the desired effect on the above-mentioned object is not impaired. Examples of such a sensitizer include stearic acid amide, palmitic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebisstearic acid amide, behenic acid amide, and methylenebis Stearamide, methylolamide, N-methylol stearamide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate, benzyl p-benzyloxybenzoate, phenyl 1-hydroxy-2-naphthoate, dibenzyl oxalate, oxalic acid -Di-p-methylbenzyl, oxalic acid-di-p-chlorobenzyl, 2-naphthylbenzyl ether, m-terphenyl, p-benzylbiphenyl, 4-biphenylparatolyl ether, di (p-methoxypheno) 1,2-di (3-methylphenoxy) ethane, 1,2-di (4-methylphenoxy) ethane, 1,2-di (4-methoxyphenoxy) ethane, 1,2-di (4 -Chlorophenoxy) ethane, 1,2-diphenoxyethane, 1- (4-methoxyphenoxy) -2- (2-methylphenoxy) ethane,
p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p-acetotoluidide, p-
Acetophenetizide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane, 1,2-bis (phenoxy Methyl) benzene, p-toluenesulfonamide,
Examples thereof include o-toluenesulfonamide, di-p-tolyl carbonate, and phenyl-α-naphthyl carbonate, but are not particularly limited thereto. These sensitizers may be used alone or in combination of two or more.

As the binder used in the present invention, completely saponified polyvinyl alcohol having a degree of polymerization of 200 to 1900, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol Modified polyvinyl alcohol such as alcohol, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, cellulose derivatives such as acetyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, polyacrylamide , Polyacrylate, polyvinyl butyral, polystyrene and copolymers thereof, polyamide resin, silicone Butter, petroleum resins, terpene resins, ketone resins, and coumarone resins. These polymeric substances include water, alcohol, ketones, esters,
In addition to being used by dissolving in a solvent such as a hydrocarbon, it can be used in a state of being emulsified or dispersed in water or another medium in the form of a paste, and used in combination depending on required quality.

The fillers that can be used in the present invention include silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene- Examples thereof include methacrylic acid copolymers, styrene-butadiene copolymers, and inorganic or organic fillers such as hollow plastic pigments.

In order to more clearly obtain the color tone of the high-temperature coloring layer, it is effective to reduce the amount of the filler in the high-temperature coloring layer or not to mix it. This is because, in the case of an additive type, a color forming composition (a reaction product of a leuco dye and a color developer, that is, a color image) formed in a high-temperature color-forming layer during high-temperature heating is not limited to a high-temperature color-forming layer. This is presumably because the mixture is easily absorbed by the filler in the layer and is efficiently mixed with the low-temperature coloring composition to obtain a high-temperature coloring tone that is a mixed color.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based and triazole-based ultraviolet absorbers, waterproofing agents such as glyoxal, dispersants, defoamers, antioxidants, fluorescent Dyes and the like can be used.

As the support, paper, recycled paper, synthetic paper, plastic film, foamed plastic film, nonwoven fabric, metal foil and the like can be used, or a composite sheet combining these can be used.

Further, for the purpose of enhancing the scratch resistance, an overcoat layer of a polymer substance or the like may be provided on the thermosensitive coloring layer. Further, for the purpose of increasing the color-forming sensitivity, an undercoat layer containing an organic filler or an inorganic filler can be provided between the color-forming layer and the support.

The amounts of the color developer and leuco dye and the types and amounts of other various components in each color forming layer of the multicolor heat-sensitive recording material of the present invention are determined according to the required performance and recording suitability, and are particularly limited. However, usually, 0 to 4 parts of a filler and 1 to 2 parts of a binder are contained in the total solid content with respect to 1 part of a developer.
5% is appropriate. The leuco dye is preferably contained in an amount of 0.1 to 2 parts with respect to 1 part of the developer.

When a leuco dye which develops a bicolor system is used as the high-temperature coloring layer and the color tone of the high-temperature coloring layer (bicolor color tone) is obtained by heating at a high temperature, the dye 1 in the low-temperature coloring layer is used.
It is effective that the amount of the dye in the high-temperature coloring layer is 1 to 3 parts, preferably about 1.5 to 2.8 parts per part. When a dye that develops a monochromatic color is used as the high-temperature coloring layer and the low-temperature coloring layer, and the color tone at the time of high-temperature heating is a multicolor coloring, the ratio of each monochromatic dye in the high-temperature coloring layer and the low-temperature coloring layer is as follows. , Can be arbitrarily adjusted according to a desired color tone.

In the present invention, the coating amount of each color-forming layer is not particularly limited, but is generally 1.5 to 1 in terms of dry weight.
It is adjusted within a range of about 2 g / m ² . Further, in the present invention, an intermediate layer can be provided between the high-temperature coloring layer and the low-temperature coloring layer. The binder, filler, sensitizer, defoamer, ultraviolet absorber, fluorescent dye, and the like described above can be appropriately blended into the coating liquid for forming the intermediate layer. Further, the coating amount of the intermediate layer may be adjusted in a range of about 1 to 10 g / m ² .

These developers, dyes, and materials to be added as necessary are pulverized by a pulverizer such as a ball mill, an attritor, a sand grinder or an appropriate emulsifier to a particle size of several microns or less, and a binder and Various coating materials are added according to the purpose to form a coating liquid. Examples of the coating method include hand coating, size press coater method, roll coater method, air knife coater method, blend coater method, flow coater method, comma direct method, gravure direct method, gravure reverse method, reverse roll coater method and the like. . After spraying, spraying or dipping, drying may be performed.

[0039]

EXAMPLES <Manufacture of thermosensitive recording medium> The thermosensitive recording medium of the present invention will be described below by way of examples. In addition, parts and% in the description
Represents parts by weight and% by weight, respectively, unless otherwise specified. Example 1 Example 1 relates to a two-color heat-sensitive recording material, and in a low-temperature color-forming layer, 4-hydroxy-4'-isopropoxydiphenylsulfone as a color developer and 3,3-bis (p-dimethylamino) as a leuco dye. Phenyl) -6-dimethylaminophthalide (blue-colored leuco dye), 3-{[(phenylamino)
Carbonyl] amino} benzenesulfonamide, 3-dibutyl-7- (o-chloroanilino) as a leuco dye
This is an example in which fluoran (a black coloring leuco dye) is used.

A developer dispersion (liquid) for a low-temperature coloring layer having the following composition and a leuco dye dispersion (blue)
Liquid), and a developer dispersion (liquid) for a high-temperature color-forming layer and a leuco dye dispersion (liquid) that develops a black color are separately wet-ground with a sand grinder until the average particle diameter is 1 micron. went. Liquid (Developer dispersion) 4-Hydroxy-4'-isopropoxydiphenyl sulfone 6.0 parts 10% Polyvinyl alcohol 18.8 parts Water 11.2 parts Liquid (blue leuco dye dispersion) 3,3-bis (P-dimethylaminophenyl) -6-dimethylaminophthalic 1.0 part 10% polyvinyl alcohol 2.3 parts water 1.3 parts liquid (developer dispersion liquid) 3-{[(phenylamino) carbonyl] amino} benzene Sulfonamide 6.0 parts 10% polyvinyl alcohol 18.8 parts Water 11.2 parts Liquid (black leuco dye dispersion) 3-dibutyl-7- (o-chloroanilino) fluoran 1.0 part 10% polyvinyl alcohol 3 parts water 1.3 parts Next, the dispersion liquid was mixed and stirred at the following ratio to prepare a dispersion liquid.

[Preparation of low-temperature coloring layer coating solution] Liquid (developer dispersion) 36.0 parts Liquid (blue leuco dye dispersion) 13.8 parts Silicon oxide pigment (25% dispersion; Mizukasil P-527) (Manufactured by Mizusawa Chemical)) 40 parts Polyvinyl alcohol (10%) 20 parts [Preparation of high-temperature coloring layer coating liquid] Liquid (developer dispersion liquid) 36.0 parts Liquid (black leuco dye dispersion liquid) 13.8 parts 20 parts of silicon oxide pigment (25% dispersion; Mizukasil P-527 (manufactured by Mizusawa Chemical)) 20 parts of polyvinyl alcohol (10%) 20 parts of the adjusted high-temperature coloring layer coating solution was applied on one side of 50 g / m ² base paper. After coating to 5.0 g / m ² , drying was performed, and 4.0 g of the low-temperature coloring layer coating solution was further applied thereon.
/ M ^2, and the sheet was treated with a super calendar so that the smoothness was 500 to 600 seconds to obtain a two-color heat-sensitive recording material.

Example 2 A two-color thermosensitive recording medium was produced in the same manner as in Example 1. However, in preparing the coating solution for the high-temperature coloring layer, no silicon oxide pigment was added.

Example 3 A two-color thermosensitive recording medium was produced in the same manner as in Example 2. However, when preparing the solution,
2,4'-Sulfonyldiphenol was used instead of hydroxy-4'-isopropoxydiphenylsulfone.

[Examples 4 and 5] A thermosensitive recording medium was produced in the same manner as in Example 2. However, when preparing the solution,
Instead of 3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-
Methylindol-3-yl) -4-azaphthalide (blue-colored leuco dye; Example 4), 3,3-bis (1-n-
Butyl-2-methylindol-3-yl) phthalide (red-colored leuco dye; Example 5) was used.

Examples 6 to 8 In the same manner as in Example 2, thermosensitive recording media were produced. However, when preparing the solution,
Instead of dibutyl-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran (black-colored leuco dye; Example 6), 3-
(N-ethyl-p-toluidino) -6-methyl-7-
Anilinofluoran (black-colored leuco dye; Example 7) and 3-dibutylamino-6-methyl-7-anilinofluoran (black-colored leuco dye; Example 8) were used.

Comparative Example 1 A thermosensitive recording medium was produced in the same manner as in Example 2. However, when preparing the solution,
Instead of {[(phenylamino) carbonyl] amino} benzenesulfonamide, 4,4′-sulfonyldiphenol (bisphenol S) was used.

<Evaluation Method> Using a thermal printer made by MARKPOINT (with a thermal head made by ROHN, equipped with KM2004-A3), the applied energy was 0.076 mj / dot as low-temperature color development and high temperature Printing was performed at 0.219 mj / dot as color development, and the obtained image and background were measured using a Macbeth densitometer (RD-914). In the measurement, the Macbeth densitometer filter used a red filter when evaluating a blue color image, a green filter when evaluating a red color image, and an amber filter when evaluating a black color image and background. .

Next, as a heat resistance test, the obtained low-temperature coloring sample was allowed to stand at 60 ° C. in a dry high-temperature atmosphere for 24 hours to obtain a low-energy printing portion (0.076 mj / do).
The color tone of t) was evaluated with a Macbeth densitometer and visually, and the degree of ground color development was evaluated with a Macbeth densitometer. Table 1 shows the obtained results.

[0049]

[Table 1] (Note) The symbol in parentheses indicates the filter of the Macbeth densitometer used. R: Red filter, G: Green filter, A: Amber filter

<Evaluation Results> In Examples 1 to 8 of the present invention, sufficient recording density and clear color tone were obtained at low applied energy (0.076 mj / dot) and high applied energy (0.219 mj / dot). Was done. Further, even after the heat resistance test, fog (black fog) and background coloration of the low energy printing portion were small, and the color separation was clearly maintained. Further, 3-{[(phenylamino) carbonyl] amino} benzenesulfonamide used as a color developer in the present invention does not cause coloring at the time of preparing a coating solution, and is excellent in handleability. On the other hand, in Comparative Example 1 in which a developing agent other than the one specified in the present invention was used in the high-temperature coloring layer, although the recording density and color separation during recording were satisfactory, the low-energy Was not able to maintain the original color tone and was discolored to black, and the ground color was larger than that of the present invention, and the heat resistance was poor.

[0051]

The multicolor heat-sensitive recording material of the present invention has a high recording density in each color tone, provides clear color development, and shows clear color separation even when exposed to high temperatures. It is extremely useful. Furthermore, since there is little background color development at high temperatures, it is suitable for applications requiring heat resistance and the like, and has high practical value.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshimi Midorikawa 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside the Product Development Laboratory of Japan Paper Machinery Co., Ltd. (72) Yoshihide Kimura 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo No. Japan Paper Manufacturing Co., Ltd. Product Development Laboratory F-term (reference) 2H026 AA07 AA14 AA28 BB12 BB24 BB39 FF07

Claims (1)

[Claims] 1. A high-temperature coloring layer containing a dye precursor and an organic developer which reacts with the dye precursor under heating to form a color on a support, and forms a color tone different from that of the high-temperature coloring layer. At least one or more low-temperature color-forming layers that exhibit color at a temperature lower than the temperature at which the high-temperature color-forming layer develops are sequentially provided, and 3-｛[(phenylamino) is used as an organic developer for the high-temperature color-forming layer.
A multicolor heat-sensitive recording material comprising: [carbonyl] amino} benzenesulfonamide.