JPS62299383A - Two-color thermal recording material - Google Patents

Abstract

PURPOSE:To enhance separation of two colors, achieve clear high-temperature color forming, suppress ground fogging and enhance contrast, by incorporating a colored pigment into a high-temperature color forming layer. CONSTITUTION:A colored pigment is incorporated in a high-temperature color forming layer, in a two-color thermal recording material comprising the high- temperature color forming layer, a decolorizing layer and a low-temperature color forming layer sequentially laminated on a support base. The colored pigment has a color complementary to the tone of color formed in the high- temperature color forming layer. The colored pigment may be, for example, a yellow, red, green or blue colored pigment derived from a monoazo pigment, diazo pigment, polyazo pigment, quinacridone, dioxazine violet, polychlorobromophthalocyanine green, phthalocyanine green or the like. The two-color thermal recording material thus obtained has excellent separation of the two colors, and is enhanced in appearance while maintaining ground brightness by controlling ground fogging of the high-temperature color forming layer by the colored pigment.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Technical Field] The present invention relates to a two-color heat-sensitive recording material, and more specifically, a two-color heat-sensitive recording material that has two-color heat-sensitive recording materials that each have different coloring heat energy and develop different tones on a support. This invention relates to a two-color heat-sensitive recording material formed by sequentially stacking color-forming layers.

[Prior art]

A thermosensitive recording material is a material in which a thermosensitive coloring layer capable of forming a colored image by heating is provided on a support such as paper, and a thermal printer equipped with a thermal head is widely used for heating.

These conventional heat-sensitive recording materials include a colorless or light-colored leuco dye (color-forming main agent) having a lactone ring, lactam ring, spiropyran ring, etc. in the heat-sensitive coloring layer, and a color developer that develops color by reacting with this leuco dye when heated. Agent (color development aid)
Those containing these are widely used because they have clear color tones and less fogging.

By the way, heat-sensitive recording materials can easily produce colored images just by heating them, so they are not only used for copying books, documents, etc., but are also used in various fields such as computer, facsimile, telex, and other fields for recording various types of information and measuring equipment. However, depending on the purpose of recording, in order to display particularly necessary data and numbers more clearly, the coloring of that part (
It goes without saying that it is desirable to be able to record with the display color (displayed color) different from the developed color of other parts.

Recently, attempts have been made to obtain multicolor recording by utilizing differences in heating temperature or thermal energy, and various multicolor thermosensitive recording papers have been proposed accordingly. Multi-color thermosensitive recording paper is generally formed by layering two types of high-temperature and low-temperature coloring layers that develop different tones with different coloring heat energies on a support, and can be broadly classified into the following two types: Divided into types. One of them is that when coloring the high temperature coloring layer, the color is mixed with the color tone of the low temperature coloring layer to obtain a color tone different from that of the low temperature coloring layer.

The other method is to use a decoloring agent that decolorizes the low-temperature color-forming layer when coloring the high-temperature color-forming layer to obtain only the color tone of the high-temperature color-forming layer without color mixing of the color tone of the low-temperature color-forming layer. As a specific example of these, the former is
Publication number, Special Publication No. 49-4342, Special Publication No. 49-277
No. 08, JP-A-48-86543, JP-A-Sho 49
-65239, etc., and the latter is
Special Publication No. 17865/1986, Special Publication No. 1786/1986
Publication No. 6, Special Publication No. 51-29024, Special Publication No. 1977
-87542 publication, JP-A-50-18048 publication,
These are disclosed in Japanese Patent Publication No. 55-36519 and the like.

However, in the case of the former multicolor thermosensitive recording paper,
When coloring at a high temperature, the color tones that can be specifically achieved are limited to black threads that have strong high-temperature coloring, such as red-black, blue-black, etc., because they are mixed with the color tone of the low-temperature coloring layer. There is. Therefore, the latter method is preferable for a two-color thermosensitive recording material, and the basic color tone of black can be used in the low-temperature coloring layer, and the coloring tone of red, blue, etc. can be obtained in the high-temperature coloring layer by a conventionally known method. be able to. However, high-temperature coloring layers obtained by conventional methods, especially red coloring types, are prone to fogging in the form of heat-sensitive coloring layer forming liquids, and even after lamination, background fogging occurs, which impairs the appearance.

〔the purpose〕

An object of the present invention is to provide a two-color heat-sensitive recording material which can obtain a blackish low-temperature coloring layer, can obtain clear high-temperature coloring without color mixture, and has excellent contrast with less background fog. .

〔composition〕

According to the present invention, in a two-color thermosensitive recording material in which a high-temperature coloring layer, a decoloring layer, and a low-temperature coloring layer are laminated in that order on a support,
A two-color thermosensitive recording material is provided, characterized in that the high-temperature coloring layer contains a colored pigment.

Coloring pigments used in the high temperature coloring layer in the present invention include:
A coloring pigment that is complementary to the color tone of the high-temperature coloring layer is used, and examples of such coloring pigments include monoazo pigments, diazo pigments, polyazo pigments, and quinacridones.

Yellow, red, green, and blue obtained from dioxazine violet, polychlorobromocyanine green, phthalocyanine green, phthalocyanine blue, iron oxide red, chrome yellow, chrome oxide green, ultramarine blue, titanium dioxide, etc. Color pigments include:

In the present invention, examples of the color developer contained in the high-temperature coloring layer and the low-temperature coloring layer include N,N'-diphenylthiourea, N-p-ethylphenyl-N'-phenylthiourea, and N-p-butylphenyl. -N'-phenylthiourea, N,N'-di-m-chlorophenylthiourea, N
, N'-di-p-chlorophenylthiourea, N, N
'-di-m-trifluoromethylphenylthiourea,
N,N'-di1rmethylphenylthiourea, 4,4'
-isopropylidenediphenol, 4,11'
-isopropylidene bis(2-chlorophenol), 4
, 4'-isopropylidene bis(2,6-dibromophenol), 4,4'-isopropylidene bis(2,
6-dichlorophenol), 4,4'-isopropylidene bis(2-methylphenol), 4,4'-isopropylidene bis(2-tert-butylphenol),
L4'-5ee-butylidene diphenol, 4.4
'-Cyclohexylidene bis(2-methylphenol), 4-tert-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 3,5-xylenol, thymol, methyl-4-hydroxybenzoate , 4-hydroxyacetophenone, novolac type phenolic resin,
2,2'-thiobis(4,6-dichlorophenol)
, catechol, resorcinol, hydroquinone, pyroganol, phloroglucin, phloroglycin carboxylic acid, 4-
tert-octylcatechol, 2,2'-methylenebis(4-chlorophenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-dihydroxydiphenyl, ethyl p-hydroxybenzoate , propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, benzyl ρ-hydroxybenzoate, p-chlorobenzyl p-hydroxybenzoate, O-chlorobenzyl p-hydroxybenzoate, p-hydroxybenzoic acid- P-methylbenzyl, p-
Hydroxybenzoic acid - n-octylbenzoic acid, zinc salicylate, ■-hydroxy-2-naphthoic acid, 2-hydroxy-6-naphthoic acid, 2-hydroxy-6-naphthoic acid substituent, 4-hydroxydiphenylsulfone, 4-hydroxy -4'-chlorodiphenylsulfone, bis(4-
(hydroxyphenyl) sulfide, etc. are used.

The leuco dyes used in the present invention can be applied singly or in combination of two or more types, but such leuco dyes include:
Those applied to this type of heat-sensitive material can be arbitrarily applied. For example, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes are preferably used. . Specific examples of such leuco dyes include those shown below.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p- dimethylaminophenyl)-6-diethylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorphthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorfur Oran.

3-dimethylamino-5,7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3-(N-p-tolyl-N-ditylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(N-(3'-trifluoromethylphenyl)amino)-6-dinithylaminofluorane, 2-(3,
6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(0-chloroanilino) ) fluoran, 3-dibutylamino-7-(0-chloroanilino)fluoran, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane.

3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluorane.

Benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylosbilane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2'-hydroxy-4'-dimethylaminophenyl) )-3-(2'-methoxy-5'-chlorophenyl) phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl) phthalide , 3-(2'-hydroxy-41-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl)phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3- (2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N -benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluorane, 3 -(N-ethyl-Phluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluoran.

3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran.

3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-
n-butylanilino)fluorane.

3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

In the present invention, specific examples of particularly preferable leuco dyes to be contained in the high temperature coloring layer include 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-cyclohexyl Examples include amino-6-chlorofluoran, 3-diethylaminobenzo[α]fluoran, and the like.

As the color erasing agent used in the present invention, various conventionally known color erasing agents such as those shown in the explanation of the prior art can be used. Formulas (1), (II), (I
Compounds represented by II), (IV) and (V) and 1
Compounds having three or more amide groups in the molecule, or two or more amide groups and one or more tertiary amino groups,
Preference is given to using N,N'-dithiocaprolactam and the like.

General formula (1) General formula (n) General formula (III) General formula (IV) General formula (V) In the above general formulas (1), (■) and (III), R2 and R3 have a substituent. is optionally alkyl, cycloalkyl, aryl or aralkyl, and X is carbonyl or sulfonyl. The alkyl represented by R□ and R2 above usually includes a straight chain or branched chain having 1 to 18 carbon atoms, the cycloalkyl includes cyclohexyl, and the aryl includes phenyl, tolyl, Examples of the aralkyl include xylyl and the like, and examples of the aralkyl include benzyl and phenethyl. These substituents can further have other substituents, such as alkyl, aryl, halogen, alkoxy, aryloxy, acyl,
Acyloxy, alkoxycarbonyl, carbamoyl,
Examples include acylamino. Also, the general formula (
One or more substituents such as alkyl, aryl, halogen, alkoxy, aryloxy, acyl, acyloxy, alkoxycarbonyl, carbamoyl, acylamino, etc. may be bonded to the piperazine ring in 1) to (m). .

Specific examples of the compound represented by the general formula (1) include the following.

N-methyl-N'-phenylacetylpiperazine, N-
Propyl-N'-phenylacetylpiperazine, N-propyl-N'-benzoylpiperazine.

N-Butyl-N'-benzoylpiperazine, N-cyclohexyl-N'-benzoylpiperazine, N-hexyl-N'-benzoylpiperazine, N-lauryl-N'-benzoylpiperazine, N-stearyl-
N'-benzoylpiperazine, N-phenyl-N'-benzoylpiperazine, N-benzyl-N'-benzoylpiperazine.

N-phenyl-N'-cyclohexyloylpiperazine.

N-phenyl-N'-acetylpiperazine.

N-phenyl-N'-lauroylpiperazine and the like.

Specific examples of the compound represented by the general formula (n) include the following.

N,N'-bis(benzenesulfonyl)piperazine.

N,N'-bis(P-methylbenzenesulfonyl)piperazine, N,N'-bis(P-isopropylbenzenesulfonyl)piperazine.

N,N'-bis(p-chlorobenzenesulfonyl)piperazine.

N,N'-bis(0-chlorobenzenesulfonyl)piperazine.

N,N'-bis(+1-chlorobenzenesulfonyl)
Piperazine, N,N'-bis(p-bromobenzenesulfonyl)piperazine, N,N'-bis(butylsulfonyl)piperazine, N
, N'-bis(octylsulfonyl)piperazine, N
, N'-bis(laurylsulfonyl)piperazine, N
, N'-bis(stearylsulfonyl)piperazine, N,N'-bis(cyclohexylsulfonyl)piperazine, N,N'-bis(p-laurylbenzenesulfonyl)
piperazine, N,N'-bis(cyclohexylsulfonyl)piperazine, etc.

Specific examples of the compound represented by the general formula (III) include the following.

N,N'-bis(butyroyl)piperazine.

N,N'-bis(hexyloyl)piperazine, N,N
'-bis(n-ofthyroyl)piperazine.

N,N'-bis(tertiary-ofthyroyl)piperazine, N,N'-bis(lauriloyl)piperazine.

N,N'-bis(stearoyl)piperazine, N,N
' -bis(pivaloyl)piperazine.

N,N'-bis(cyclohexyloyl)piperazine.

N,N'-bis(p-methylcyclohexyloyl)piperazine, N,N'-bis(p-methylphenylacetyl)piperazine, N,N'-bis(phenylacetyl)piperazine, N
, N'-bis(phenylpropionyl)piperazine.

N,N'-bis(benzoyl)piperandine, N,N
'-bis(phenoxyacetyl)piperazine, N,N
'-bis(P-chlorobenzoyl)piperazine.

N,N'-bis(2-phenoxypropionyl)piperazine and the like.

In the general formula (mV), RL, R,, R1 and R4
represents substituted or unsubstituted alkyl, cycloalkyl, aryl or aralkyl, R□ and R2 or R3 and R4
can also form a ring by bonding their ends together. The alkyl usually includes a straight chain or branched chain having 4 to 18 carbon atoms, the cycloalkyl includes cyclohexyl, and the aryl includes:
Examples of aralkyl include phenyl, tolyl, xylyl and the like, and examples of aralkyl include benzyl and phenethyl. These substituents are.

It may further have other substituents, such as alkyl, aryl, alkoxy, acyl, halogen, acylamino such as benzoylamino, acetylamino, alkoxycarbonyl, carbamoyl, aryloxy, etc. , aralkyloxy, and the like. A is a fatty acid group or an aromatic group, and in the case of an aliphatic group, it is usually substituted or unsubstituted and has 1 to 1 carbon atoms.
8, and in the case of an aromatic group, it is substituted or unsubstituted arylene such as phenylene, tolylene, xylylene, etc. In this case, the substituents include the above-mentioned halogen, acylamino, alkoxycarbonyl, carbamoyl, Examples include aryloxy and aralkyloxy.

Specific examples of the disubstituted amide compounds of aliphatic and aromatic dihydric carboxylic acids include the following.

N, N, N'N' -tetrabutylsuccinic acid diamide, N, N, N'N' -tetrabutylcooctalytic acid diamide, N, N, N'N' -tetralauryl succinic acid diamide, N, N, N 'N'-tetrastearylsuccinic acid diamide, N,N,N'N'-tetraphenyladipic acid diamide, N,N,N'N'-tetra-p
-Butylphenyladipate diamide, N,N,N'N' -Tetrabutyladipate diamide, N,N,N'N' -Tetraoctyladipate diamide, N,N,N'N' -Tetralauryladipate diamide, N,N,N'N'-tetrastearyladipate diamide, N,N'-dicyclohexyl-N,N'-dimethylsuccinic acid diamide, N,N'-isophthaloyl bispyrrolidine, N,N '
-phthaloyl bispyrrolidine.

N, N'-terephthaloylbis-diethylamine, N
, N'-isophthaloylbis-diethylamine, N,
N'-phthaloylbis-diethylamine, N,N'
-Terephthaloylbis-dipropylamine, N, N'
-Isophthaloylbis-dipropylamine, N, N'
-Terephthaloylbis-dibutylamine, N,N'-
Isophthaloyl bis-dibutylamine, N, N'-
Terephthaloylbis-cyclohexyl-methylamine, N,N'-isophthaloylbiscyclohexyl-methylamine, N,N'-terephthaloylbis-dicyclohexyl-
Amine, N,N'-isophthaloylbis-dicyclohexyl-
Amin et al.

In the general formula (V), R1 and R2 represent alkyl, cycloalkyl, aryl, or aralkyl which may have a substituent, and the alkyl is usually a linear or branched chain having 1 to 18 carbon atoms. Examples of the cycloalkyl include cyclohexyl, examples of the aryl include phenyl, tolyl, and xylyl, and examples of the aralkyl include benzyl and phenethyl.

These substituents can further have other substituents, such as alkyl.

In addition to aryl and halogen, substituents such as alkoxy, aryloxy, aralkyloxy, acyl, acyloxy, alkoxycarbonyl, carbamoyl, and acylamino may be mentioned. 6Y and Y2 are linear or branched carbon atoms of 1 to 18 is an alkylene group.

Specific examples of such compounds include the following.

N,N'-bis(benzoylaminoethyl)piperazine, N,N'-bis(benzoylaminopropyl)piperazine, N,N'-bis(benzoylaminobutyl)piperazine, N,N'-bis(cyclohexylaminopropyl) piperazine.

N,N'-bis(hexyloylaminopropyl)piperazine, N-benzoylaminopropyl-N'-cyclohexylaminoethylpiperazine.

N-Benzoylaminopropyl-N'-benzoylaminobutylpiperazine, N-(P-chlorobenzoylaminoamino)-N'-benzoylaminopropylpiperazine, N-cyclohexylaminopropyl-N'-cyclohexylaminobutyl Piperazine et al.

Further, specific examples of the compound having three or more amino groups, two or more amide groups, and one or more tertiary amino groups in the molecule include, for example, the following.

N,N',N'-tribenzoyl-diethylenetriamine, N,N'-N'-tribenzoyl-dipropylenetriamine, N,N',N',N-tetrabenzoyl-triethylenetetramine, 1,7-dibenzoyl -4-Methyl-diethylenetriamine, 1.9-dibenzoyl-5-methyl-dipropylenetriamine, 1.7-diα-naphthoyl-4-methyl-diethyltriamine, 1.7-diα-naphthoyl-4-cyclohexyl- Diethylenetriamine.

N,N',N'-tripivaloyl-diethylenetriamine.

N, N', N', N-tetraacetyl-triethylenetetramine.

N, N', N', N-tetracyclohexyloyl-
Triethylenetetramine etc.

In the present invention, in order to bind and support the leuco dye, color developer, and decolorizer on the support, various conventional binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, methoxycellulose,
Cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid ester/methacrylic acid ternary copolymer, styrene Water-soluble polymers such as / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer Latexes such as polyacrylic acid, polyacrylic acid ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc. can be used.

In addition, in the present invention, in addition to the leuco dye and color developer, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers and surfactants, may be used in combination, if necessary. In the case of , fillers include, for example,
Calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay,
In addition to inorganic fine powders such as talc, surface-treated calcium and silica, organic fine powders such as urea-polymarine resin, styrene/methacrylic acid copolymer, and polystyrene tallow can be used. Further, if necessary, a thermofusible substance commonly used in this type of field can be used for the low-temperature coloring layer. In this case, examples of the thermofusible substance include higher fatty acids or their esters, amides, In addition to metal salts, various waxes, condensates of aromatic carboxylic acids and amines, phenyl benzoate, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalates, higher ketones, and other thermoplastics. 5 of fusible organic compounds, etc.
Examples include those having a melting point of about 0 to 200°C.

Further, in the present invention, a protective layer may be provided on the low-temperature coloring layer in order to improve matching properties (head dregs, sticking, etc.) with the thermal head.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Example 1 Each of the following ingredients was prepared using a sand mill to give an average particle size of 2 to 2.
The material was pulverized and dispersed to a particle size of 3 μm to prepare a dispersion liquid.

[Dispersion liquid-A]

3-(N-ethyl-N-amylamino)-6-methyl-
7-anirite fluorane (black) 20 parts 10% polyvinyl alcohol aqueous solution 20n water
60II [Dispersion-B] 3,3'-dichlorophenylthiourea 10 parts Calcium carbonate 10 Polyvinyl alcohol (10% aqueous solution) 200 Water
6o [Dispersion-〇] 3-diethylamino-7-chlorofluoran (red) 2
0 parts 10% hydroxyethyl cellulose aqueous solution 2 o water

6o [Dispersion D] Bisphenol A 10 parts Calcium carbonate 1o 10%
Polyvinyl alcohol aqueous solution 2o water
6o
〃10 parts of dispersion A mvsd as above, 8 parts of dispersion
70 parts and 10 parts of water were respectively mixed and stirred to obtain a low-temperature coloring layer forming liquid. On the other hand, dispersion liquid CIO part, dispersion liquid 070
1 part, 20 parts of water, and 0.008 part of a 20% phthalocyanine blue aqueous dispersion were mixed and stirred to obtain a high-temperature coloring layer forming solution.

Further, a decolorizing agent layer forming liquid for forming a decolorizing agent layer was prepared at the following ratio.

[Decolorizer layer forming liquid]

4.4-dithiodimorpholine 20 parts l
0% polyvinyl alcohol aqueous solution 20〃water

6o Next, apply the above-mentioned high-temperature coloring layer forming liquid (coating amount when dry: 5 g/r
rr), erasing agent layer forming liquid (dry coating amount: 2.5 g/r
rf) and low-temperature coloring layer forming liquid (dry coating amount: 3.5g
/rrr) was applied and dried, and then the smoothness was 50 (1-1
A two-color heat-sensitive recording material of the present invention was obtained by calendering for 500 seconds.

Comparative Example 1 A two-color heat-sensitive recording material of Comparative Example 1 was obtained in the same manner as in Example 1 except that the phthalocyanine blue aqueous dispersion was removed from the high-temperature color forming layer forming liquid of Example 1.

For the two-color heat-sensitive recording materials of Examples and Comparative Examples obtained as described above, dynamic color development characteristics and color tone of the background area were measured using a color difference meter using a G-+11 facsimile test machine. The results are shown in Table 1 below.

The color development tester has an 8 dot/+s thermal head manufactured by Kenshi Electronics Co., Ltd., and the heating element resistance is approximately 40.
0Ω/dat, 1 Color development test is main scanning recording speed 2
0+m5sc/1ine, sub-scanning 3.85 Q/mt
m, platen suppression 3.0kg/cd, head input 0.6
The test was conducted under w/dat (7) conditions.

In addition, the densitometer is a Macbeth densitometer (RD-514 filter 11-106 black color, 58 red color).The color difference meter is DICOM ND-50 manufactured by Nippon Heavy Industries Co., Ltd.
4DH was used.

Table 1 [Effects] As shown in Table 1, the two-color heat-sensitive recording material of the present invention has excellent two-color separation properties, and the whiteness of the background can be improved by adjusting the background fog of the high-temperature coloring layer with a coloring pigment. A two-color heat-sensitive recording material with excellent appearance can be obtained without lowering the quality.

Claims (1)

[Claims] (1) A two-color thermosensitive recording material in which a high-temperature coloring layer, a decoloring layer, and a low-temperature coloring layer are laminated in that order on a support, characterized in that the high-temperature coloring layer contains a colored pigment. Recording materials.