JPS62236791A - Two-color thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a two-color thermal recording material imparting high low temp. developed color density, excellent in high temp. color forming sensitivity and forming a low temp. developed color image having good storage stability, by providing an intermediate layer of a leuco dye or a coupling substance between a decolorizing layer and a second thermal color forming layer. CONSTITUTION:An intermediate layer based on either one of a leuco dye and a coupling substance is provided between a decoloring layer and a second thermal color forming layer. The intermediate layer is desirably formed in a coating amount of 0.2-2g/m<2> in order to sufficiently develop the effect of said layer and, if necessary, a small amount of a heat-meltable substance or inorg. and org. fillers such as wax or a sensitizer are pref. added to the intermediate layer. This inventive two-color thermal recording material can be obtained by a method wherein a liquid having the color forming dye, the coupler, a decolorizing agent and a binder etc. dispersed or dissolved therein is applied to one surface of a support such as paper, synthetic paper or a plastic film to be dried and this operation is repeated. The coating and adhering amount of a high temp. color forming layer is pref. 0.3-1.0g/m<2> and the adhesion amount (coating amount) of the decoloring agent is pref. 0.5-5g/m<2> and the adhesion amount of a low temp. color forming layer is pref. 0.2-0.8g/m<2>. The wt. ratio of the dye and the coupler is pref. 1:1-1:5.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a two-color heat-sensitive recording material, and more specifically, the present invention relates to a two-color heat-sensitive recording material, and more specifically, a two-color heat-sensitive recording material in which heat-sensitive color-forming layers each having a different color-forming heat energy and a different color tone are sequentially laminated on a support. The present invention relates to the formed multicolor thermosensitive recording material.

[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 (coloring 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 records using differences in heating temperature or thermal energy.

Accordingly, various multicolor thermosensitive recording papers have been proposed. Multi-color thermosensitive recording paper is generally formed by stacking 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 No. 48-86543.

The latter is described in Japanese Patent Publication No. 49-65239, etc., and the latter is described in Japanese Patent Publication No. 50-17865, Japanese Patent Publication No.
-17866 Publication, Special Publication No. 51-29024,
Japanese Patent Publication No. 51-87542, Japanese Patent Publication No. 50-1804
8, Japanese Patent Publication No. 55-36519, etc., respectively.

However, in the case of the former multicolor thermosensitive recording paper,
When coloring at a high temperature, the color tones that can be concretely achieved in order to mix the color with the color tone of the low temperature coloring layer are limited to black threads where the high temperature coloring tone is strong, such as red-black, blue-black, etc. There is. On the other hand, in the case of the latter multicolor thermosensitive recording paper, the combination of color tones can be freely selected, but when the coloring layer on the high temperature side is colored, an eraser containing a decoloring agent that erases the coloring layer on the low temperature side is used. It is necessary to provide a color layer. Although various materials have been provided as decolorizing agents for this purpose, no satisfactory material has been found so far. For example, in Japanese Patent Publication No. 51-19992, acetamide, stearamide, phthalonitrile,
II+-nitroaniline, β-naphthylamine, etc. are disclosed, but among these, stearamide,
Phthalonitrile can generally be used as a sensitizer, and its decolorizing effect is negligible. Furthermore, m-nitroaniline and β-naphthylamine show some decolorizing effect.

Not only is it highly degradable and easily turns yellow, but it is also highly soluble in water, so even low-temperature colored images can be easily discolored, and it is also toxic by causing skin irritation.

It cannot be said to be a practical material. Japanese Patent Publication No. 54-36864 proposes quaternary ammonium salts of amine derivatives, but quaternary ammonium salts of amine derivatives have high water solubility and poor storage stability of images, making them impractical. However, in the case of amine derivatives, hexadecylamine, tribenzylamine, tricyclohexylamine, dioctadecylamine, N,N-dibenzylpiperazine, cyclohexyldibenzylamine, etc. are mentioned.

Primary amines have poor stability in air, and secondary amines and tertiary amines in which only an alkyl group, aryl group, or aralkyl group is substituted for the nitrogen atom also have poor storage stability.
Although guanidine derivatives are disclosed in Japanese Patent Publication No. 51-29024, which cannot be said to be practical, guanidine is highly water-soluble.

It is necessary to add a hydrophobic group such as phenyl or cyclohexyl or to dimerize it to make it poorly soluble in water to improve its storage stability. Although these materials exhibit a certain degree of color erasing effect and can be said to be practically practical materials, they have the disadvantage of being easily thermally decomposed, and have the problem of being prone to gas generation and having poor storage stability.

Considering the above-mentioned problems, the material properties required for a color erasing agent are that it should be basic, be sparingly soluble in water, have a melting point of at least 80°C, and be resistant to exposure to air or heat. Examples include being stable and having little toxicity.

In view of the current situation, the present applicant has developed a decolorizing agent superior to the conventional decolorizing agents mentioned above, and has discovered a new layer structure using the decolorizing agent, and has already published Japanese Patent Application No. 59-24133, Application No. 59-273816, Patent Application No. 11377-1983,
Applications have been filed under Japanese Patent Application No. 11378/1982, No. 64894/1983, etc.

However, even when these color erasing agents are used, the color image of the second thermosensitive coloring layer may have a low density due to the action of the color erasing agent, or the color may fade during storage. The reality is that an intermediate layer is provided between the decoloring layer and the second thermosensitive coloring layer.

Therefore, the stability of the colored image of the second heat-sensitive coloring layer during storage was extremely poor, but during high-temperature coloring, the decoloring agent and the second heat-sensitive coloring layer are made to dissolve through the intermediate layer. This requires a considerable amount of thermal energy.

Another problem is that sufficiently clear high-temperature coloring cannot be obtained. Furthermore, the density of low-temperature color images is still insufficient.

〔the purpose〕

An object of the present invention is to provide a low-temperature colored image with high density.

Another object of the present invention is to provide a two-color heat-sensitive recording material that provides clear images with excellent stability during storage and requires less thermal energy during high-temperature color development.

〔composition〕

According to the present invention, on one side of the support, the first laminates each having different coloring heat energies and developing colors in different tones are provided.
and second thermosensitive coloring layers are stacked so that the one with smaller coloring heat energy is the upper layer, and between the two thermosensitive coloring layers, there is a decoloring layer for the coloring system of the second thermosensitive coloring layer. In a two-color heat-sensitive recording material provided with a decoloring layer containing a decoloring agent as a main component.

A two-color thermosensitive recording material is provided, characterized in that an intermediate layer containing either a leuco dye or a color developing substance as a main component is provided between the decoloring layer and the second thermosensitive coloring layer. .

In the present invention, the intermediate layer containing either a leuco dye or a color developing substance as a main component functions to increase the coloring density of the first thermosensitive coloring layer during low-temperature coloring.

Furthermore, in the case of high-temperature coloring, the compatibility between the decolorizing layer and the first heat-sensitive coloring layer is better than when a wax-like substance is used as the intermediate layer, so the low-temperature coloring density is high and the high-temperature coloring is low. It is thought that this can be clearly obtained with energy.

In addition, this intermediate layer prevents the eutectic formation of the color-erasing layer and the first color-forming layer, and is therefore considered to prevent the color-erasing agent from acting and decoloring the low-salt color-forming image during storage.

The intermediate layer of the present invention is desirably formed with a coating amount of 0.2 to 2 g/rd in order to fully exhibit its effect, and may be coated with a small amount of wax, sensitizer, etc. as needed. It is preferable to add a fusible substance or an inorganic or organic filler. In addition, the leuco dye□ or color developing substance used is
Although commonly used dyes can be used, it is preferable to use the same leuco dye or color developing substance as that of the first heat-sensitive coloring layer from the viewpoint of not lowering the melting point.

As the decolorizing agent used in the present invention, those conventionally used can be used, but (a) the following general formula (1), (II) or (IV
) Piperazine derivatives represented by (b) the following general formula (
III) A disubstituted amide compound of a dicarboxylic acid represented by (c) having three or more amide groups in the molecule, or having two or more amide groups and one or more tertiary amine groups It is preferable to use at least one kind selected from the compounds.

General formula (■) 2 General formula (■) 2 General formula (■) 2 General formula (■): In the general formula (1), (II), (m) and (IV),
R1, R2, R3, R4, R5, R6, R7, R,, R
9 and RIO are alkyl, cycloalkyl, aryl or aralkyl which may have a substituent, and R5
The terminals of R6 and R7 and R8 may be bonded to each other to form a cyclic structure. Further, A represents a divalent aliphatic group or an aromatic group, X, Xl and x2 are carbonyl or sulfonyl, and Yl and Yl represent alkylene. The alkyl represented by R1 to Lo 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, for example,
In addition to alkyl, aryl, halogen, etc., alkoxy, aryloxy, acyl, acyloxy, alkoxycarbonyl, carbamoyl, acylamino, etc. can be mentioned. The piperazine ring in general formulas (1), (n) and (mV) also has one or more substituents such as alkyl, aryl, halogen, alkoxy, aryloxy, acyl, acyloxy, alkoxycarbonyl, carbamoyl, acylamino, etc. Two or more may be combined.

Specific examples of the compound represented by the general formula (ri) include:
Examples 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, N-phenyl-Nl
-p-methylbenzoylpiperazine, N-phenyl-N'-p-chlorobenzoylpiperazine.

N-benzoylaminoethyl-N'-benzoylpiperazine, N-benzoylaminopropyl-N'-benzoylpiperazine, N-benzoylaminobutyl-N'-benzoylpiperazine.

N-benzoylaminopropyl-N'-cyclohexylpiperazine, N-cyclohexylaminopropyl-N'-cyclohexyloylpiperazine, N-benzoylaminoamyl-N'-benzoylpiperazine, N-(p-chlorobenzoylamino amyl)-N'-(
Chlorobenzoyl) piperazine.

N-phenyl-N'-benzenesulfonylpiperazine, N-benzyl-N'-benzenesulfonylpiperazine, N-Methyl-N'-benzenesulfonylpiperazine.

N-propyl-N'-benzenesulfonylpiperazine, N-butyl-N'-benzenesulfonylpiperazine, N-hexyl-N'-benzenesulfonylpiperazine, N-cyclohexyl-N'-benzenesulfonylpiperazine, N-lauryl-N '-Benzenesulfonylpiperazine, N-stearyl-N'-benzenesulfonylpiperazine.

N-'Phenyl-N'-butylsulfonylpiperazine.

N-phenyl-N'-laurylsulfosulpiperazine.

N-phenyl-N'-stearylsulfonylpiperazine, N-phenyl-N'-cyclohexylsulfonylpiperazine, N-phenyl-N'-benzylsulfonylpiperazine.

N-phenyl-N'-(p-methylbenzenesulfonyl)piperazine, N-butyl-N'-(p-methylbenzenesulfonyl)piperazine, N-benzoylaminopropyl-N'-benzenesulfonylpiperazine, N-benzoylaminopropyl -N'-p-methylbenzenesulfonylpiperazine, N-benzoylaminoethyl-N'-benzenesulfonylpiperazine, N-benzoylaminobutyl-N'-benzenesulfonylpiperazine, N-benzoylaminopropyl-N'-butanesulfonylpiperazine, N-naphthoylaminopropyl-N'-benzenesulfonylpiperazine, N-benzenesulfonylaminopropyl-N'-benzenesulfonylpiperazine, N-butyroylaminopropyl-N'-benzoylpiperazine.

N-hexyloylaminopropyl-N'-benzoylpiperazine, N-lauroylaminopropyl-N'-benzoylpiperazine.

N-stearoylaminopropyl-N'-benzoylpiperazine, N-stearoylaminopropyl-N'-benzenesulfonylpiperazine, etc.

Specific examples of the compound represented by the general formula (II) 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(m-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, N-butylsulfonyl-N'-benzenesulfonylpiperazine, N-octylsulfonyl-N'-benzenesulfonylpiperazine, N-(o-chlorobenzenesulfonyl)-N'-benzenesulfonyl piperazine, N-lauroyl-N'-benzenesulfonylpiper--φhun, N-lauroyl-N'-(p-methylbenzenesulfonyl)piperazine.

N-benzoyl-N'-benzenesulfonylpiperazine, N-(o-chlorobenzoyl)-N'-benzenesulfonylpiperazine, N-(o-methylbenzoyl)-N'-benzenesulfonylpiperazine, 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(ρ
-methylcyclohexyloyl)piperazine, M, 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, N,N'-bis(Im-chlorobenzoyl)piperazine, N,N'-bis(0-chlorobenzoyl)piperazine, N,N'-bis(p-methyl benzoyl) piperazine.

N,N'-bis(+S-methylbenzoyl)piperazine, N,N'-bis(0-methylbenzoyl)piperazine.

N,N'-bis(0-acetyloxybenzoyl)bipe-radizine, N,N'-bis(0-butyryloxybenzoyl)piperazine, N,N'-bis(p-phenylbenzoyl)piperazine, N,N '-bis(P-methoxycarbonylbenzoyl)piperazine, N,N'-bis(p-isopropoxycarbonylbenzoyl)piperazine, N,N'-bis(p-octadecylcarbamoylbenzoyl)piperazine, and the like.

In the general formula (m), R5, R,, R7 and R8 represent substituted or unsubstituted alkyl, cycloalkyl, aryl or aralkyl, and R5 and R6 or R7 and R8 are
The ends can also be joined together to form a ring. The alkyl usually includes a straight chain or branched chain having 4 to 18 carbon atoms, the cycloalkyl includes cyclohexyl, the aryl includes phenyl, tolyl, xylyl, etc. Examples of alkyl include benzyl and phenethyl. These substituents may further have other substituents, such as alkyl, aryl, alkoxy, acyl, halogen, etc., as well as acylamino such as benzoylamino, acetylamino, alkoxy Carbonyl, carbamoyl, aryloxy, aralkyloxy and the like can be mentioned. A is an aliphatic group or an aromatic group; in the case of an aliphatic group, it is usually substituted or unsubstituted alkylene having 1 to 8 carbon atoms; in the case of an aromatic group,
Substituted or unsubstituted arylene such as phenylene, tolylene, and base silylene, and the like. In this case, examples of the substituent include the above-mentioned halogen, acylamino, alkoxycarbonyl, carbamoyl, 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'-tetraoctylsuccinic acid diamide.

N, N, N', N'-tetralaurylsuccinic 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'-tetralauryladipic acid diamide, N,N,N',N'-tetrastearyladipic acid diamide-N,N'-dicyclohexyl-N,N'-dimethylsuccinic acid diamide .

N,N'-dicyclohexyl-N,N'-dimethylglutarate diamide, N,N'-dicyclohexyl-N,N'-dimethyladipic acid amide, N,N,N',N'-tetracyclo Xyladipic acid diamide.

N,N'-dimethyl-N,N'-dicyclohexylsperate diamide, N,N'-dimethyl-N,N'-dicyclohexylsebacic acid diamide, N,N'-dimethyl-N,N'-dicyclohexylmalone Acid diamide, N,N,N',N'-tetrabenzyladipic acid diamide, adipoyldipiperidine, adiboyldipipecoline, adipoyl-di-ε-caprolactam, adipoyldi-
Pyrrolidone, adiboyldipiperidone, sebacoyl-di-E-caprolactam, sebacoyl-di-piperidone, adipoyl-di-3-chloro-ε-caprolactam, succinyl-di-3-chloro-ε-caprolactam, and the like.

N, N'-terephthaloyl bispiperidine.

N,N'-isophthaloyl bispiperidine.

N,N'-phthaloyl bispiperidine, N,N'-
Terephthaloyl bismorpholine.

N,N'-isophthaloyl bismorpholine, N,N'
-phthaloylbismorpholine, N,N'-terephthaloylbis-4-methylpiperazine, N,N'-isophthaloylbis-4-methylpiperazine, N,N'-phthaloylbis-4-methylpiperazine,
N,N'-terephthaloylbis-4-phenylpiperazine, N,N'-isophthaloylbis-4-phenylpiperazine, N,N'-phthaloylbis-4-phenylpiperazine, N,N'-terephthaloy Rubis-4-propylpiperazine, N,N'-isophthaloylbis-4-propylpiperazine, N,N'-phthaloyl-4-propylpiperazine, N
, N'-terephthaloyl biscaprolactam.

N, N'-isophthaloyl biscaprolactam, N,
N'-phthaloyl biscaprolactam, N, N'-
Terephthaloylbis-3-chlorocaprolactam, N,N'-isophthaloylbis-3-chlorocaprolactam, N,N'-phthaloylbis-3-chlorocaprolactam, N,N'-terephthalolbisvalerolactam, N, N
'-Isophthaloyl bisvaleractam, N, N'
-phthaloylbiscaprolactam, N,N'-terephthaloylbispyrrolidine, N,N'-isophthaloylbispyrrolidine, N,N'-phthaloylbispyrrolidine.

N, N'-terephthaloylbis-diethylamine, N
, N'-isophthaloylbis-diethylamine, N,
N'-phthaloylbis-diethylamine.

N, N'-terephthaloyl bis-dipropylamine, N,N'-isophthaloylbis-dipropylamine.

N, N'-terephthaloylbis-dibutylamine, N
, N'-isophthaloylbis-dibutylamine, N,
N'-terephthaloylbis-cyclohexyl-methylamine.

N,N'-isophthaloylbiscyclohexyl-methylamine, N,N'-terephthaloylbis-dicyclohexyl-
Amine N,N'-isophthaloylbis-dicyclohexyl-
Amine, N,N'-terephthaloylbis-dibenzylamine, N,N'-isophthaloylbis-dibenzylamine.

N,N'-terephthaloylbis-dioctylamine, N,N'-isophthaloylbis-dioctylamine, N,N'-terephthaloylbis-jethoxypropylamine, N,N'-terephthaloylbis -4-chlorobutylamine, N,N'-terephthaloylbis-dibenzoylaminoethylamine, N,N'-isophthaloylbis-dibenzoylaminoethylamine.

N,N'-terephthaloylbis-benzoylaminopropylamine, N,N'-isophthaloylbis-benzoylaminopropylamine, N,N'-terephthaloylbis-diacetylaminoethylamine, N,N'-iso Phthaloylbis-diacetylaminoethylamine, N,N'-terephthaloylbis(4-methylpiperidine), N,N'-terephthaloylbis(3-methylpiperidine), N,N'-terephthaloylbis(3-methylpiperidine), N,N'-terephthaloylbis(3-methylpiperidine), , 5-dimethylpiperidine), N,N'-terephthaloylbis(2-methylpiperidine).

N,N'-terephthaloylbis(2,6-dimethylpiperidine), N,N'-isophthaloylbis(4-methylpiperidine), N,N'-phthaloylbis(4-methylpiperidine)
, N,N'-isophthaloylbis(3-methylpiperidine), N,N'-phthaloylbis(3-methylpiperidine)
, N,N'-isophthaloylbis(3,5-dimethylpiperidine).

N,N'-phthaloylbis(3,5-dimethylpiperidine), N,N'-isophthaloylbis(2-methylpiperidine).

N,N'-phthaloylbis(2-methylpiperidine)
, N,N'-isophthaloylbis(2,6-dimethylpiperidine), N,N'-phthaloylbis(2,6-dimethylpiperidine), N,N'-terephthaloylbis(4-benzylpiperidine), N,N'-isophthaloylbis(4-benzylpiperidine), N,N'-phthaloylbis(4-benzylpiperidine), N,N'-terephthaloylbis(4-methoxycarbonylpiperidine), N,N' -Isophthaloyl bis(4-methoxycarbonylpiperidine).

N,N'-terephthaloylbis(2-methoxycarbonylpiperidine), N,N'-isophthaloylbis(2-methoxycarbonylpiperidine), N,N'-phthaloylbis(2-methoxycarbonylpiperidine).

N, N'-terephthaloyl bis(4-ethylpiperidine), N, N'-terephthaloyl bis(4-propylpiperidine), N, N'-terephthaloyl bis(4-butylpiperidine), N, N'-isophthaloylbis(4-ethylpiperidine), N,N'-isophthaloylbis(4-n-n-propylpiperidine), N,N'-isophthaloylbis(4-butylpiperidine), N,N '-Isophthaloyl bis(4-butylpiperidine), N,N'-phthaloyl bis(4-ethylpiperidine)
.

N,N'-phthaloylbis(4-propylpiperidine), N,N'-phthaloylbis(4-butylpiperidine)
N,N'-terephthaloylbis(3-hydroxymethylpiperidine), N,N'-isophthaloylbis(3-hydroxymethylpiperidine), N,N'-phthaloylbis(3-hydroxymethylpiperidine), N, N'-terephthaloyl bis(5-ethyl-2-methylpiperidine), N,N'-isophthaloyl bis(5-ethyl-2-methylpiperidine), N,N'-phthaloyl bis(5-ethyl-2 -methylpiperidine), N,N'-terephthaloylbis(N-ethyl-N'
-cyclohexylamine), N,N'-isophthaloylbis(N-ethyl-N'
-cyclohexylamine), N,N'-phthaloylbis(N-ethyl-N'-cyclohexylamine), N,N'-terephthaloylbis(N-propyl-N'
-cyclohexylamine), N,N'-isophthaloylbis(N-propyl-N'
-cyclohexylamine).

N,N'-phthaloylbis(N-propyl-N'-cyclohexylamine), N,N'-terephthaloylbis(N-butyl-N'
-cyclohexylamine), N,N'-isophthaloylbis(N-phthyl-N'
-cyclohexylamine), N,N'-phthaloylbis(N-butyl-N'-cyclohexylamine), N,N'-terephthaloylbis(4-ethyloxymethylpiperidine), N,N'-isophthaloyl rubis(4-ethyloxymethylpiperidine), N,N'-terephthaloylbis(4-ethyloxyethylpiperidine), N,N'-isophthaloylbis(4-ethyloxyethylpiperidine), N,N' -Terephthaloyl bis(2-methoxyethylpiperidine), N,N'-isophthaloylbis(2-methoxyethylpiperidine), N,N'-terephthaloylbis(4-methoxyethylpiperidine), N,N '-Isophthaloylbis(4-methoxyethylpiperidine), N,N'-terephthaloylbis(4-phenylpiperidine), N,N'-isophthaloylbis(4-phenylpiperidine), N,N' -phthaloylbis(4-phenylpiperidine), N,N'-terephthaloylbis(4-phenylpropylpiperidine), N,N'-isophthaloylbis(4-phenylpropylpiperidine), N,N'-phthaloylbis( 4-phenylpropylpiperidine) etc.

In the general formula (IV), R9 and flio represent alkyl, cycloalkyl, aryl, or aralkyl which may have a substituent. The alkyl usually includes a straight chain or branched chain having 1 to 18 carbon atoms,
Cycloalkyl includes cyclohexyl,
Examples of aryl include phenyl, tolyl, xylyl, etc., and examples of aralkyl include benzyl, phenethyl, etc. These substituents can further have other substituents, such as alkyl, aryl, halogen, alkoxy, aryloxy, aralkyloxy, acyl, acyloxy, alkoxycarbonyl, carbamoyl, Examples include substituents such as acylamino. □ and Y2 are linear or branched alkylene groups having 1 to 18 carbon atoms.

Specific examples of the compound represented by the general formula (IV) 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(hexyl) siloylaminopropyl)piperazine, N-benzoylaminopropyl-N'-cyclohexylaminoethylpiperazine, N-benzoylaminopropyl-N'-benzoylaminobutylpiperazine.

N-(P-chlorobenzoylaminoamyl) -N'-
Benzoylaminopropylpiperazine, N-cyclohexylaminopropyl-N'-cyclohexylaminobutylpiperazine, N-naphthoylaminopropyl-N'-benzoylaminopropylpiperazine.

N-butyroylaminopropyl-N'-benzoylaminopropylpiperazine.

N-Lauroylaminopropyl-N'-benzoylaminopropylpiperazine, N-stearoylaminopropyl-N'-benzoylaminopropylpiperazine, N-butyroylaminopropyl-N'-cyclohexylaminobutylpiperazine.

N-naphthoylaminopropyl-N'-lauroylaminopropylpiperazine, N-naphthoylaminopropyl-N'-stearoylaminopropylpiperazine, and the like.

Further, specific examples of the compound having three or more amino groups in the molecule, or having two or more amide groups and one or more tertiary amino group include 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-di-α-naphthoyl-4-methyl-diethyltriamine, 1.7-di-α-naphthoyl-4-cyclohexyl-diethylenetriamine, N, N', N"-tripivaloyl-diethylenetriamine, N, N', N' , N-1tetraacetyltriethylenetetramine, N,N',N',N-1tetracyclohexyloyl-triethylenetetramine.

Ethylenediaminetetraacetic acid tetraanilide, ethylenediaminetetraacetic acid tetracyclohexylamide.

Ethylenediaminetetraacetic acid tetra-2-ethylhexylamide, ethylenediaminetetraacetic acid tetralaurylamide, ethylenediaminetetraacetic acid tetrastearylamide, ethylenediaminetetraacetic acid tetrapiperidide.

Ethylenediaminetetraacetic acid tetra-ε-cabrolactamide, etc.

In addition, polyethers, polyethylene glycol derivatives, solid alcohols, aliphatic or aromatic amines, guanidine derivatives, morpholine derivatives, etc. can be used as decolorizing agents.

In the present invention, the coloring agent used in the second thermosensitive coloring layer forms a stable image with low energy heating.

Any dye may be used as long as it is easily decolored by a decoloring agent under high-energy heating, and in the case of the present invention, a basic leuco dye is used. The coloring agent used in the second thermosensitive coloring layer may be any coloring agent as long as it is not easily erased by the decoloring agent. Therefore, the coloring agent used in the first thermosensitive coloring layer is not limited to leuco dyes, but may be other than conventionally known coloring agents. Thermosensitive coloring type ones are also used. Further, a protective layer may be provided on the second thermosensitive coloring layer in the form of one layer or multiple layers.

The basic leuco dye used in the second heat-sensitive coloring layer of the present invention may be applied alone or in a mixture of two or more types, and such basic leuco dyes are applied to this type of heat-sensitive material. For example, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes are preferably used.

A specific example of such a basic leuco dye is
r Examples include those shown below.

3.3-Bis(P-dimethylaminophenyl)-phthalide.

3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystalno(iolet lactone), 3.3-bis(p-dimethylaminophenyl)-6-diethylaminophenyl.

3.3-Bis(P-dimethylaminophenyl)-6-chlorphthalide.

3.3-bis(p-dibutylaminophenyl) phthalate 3-cyclohexylamino-6-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-dimethylamino-5,7-dimethyl Fluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane.

3-(N-p-tolyl-N-dithylamino)-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 -(O-chloroanilino)fluorane.

3-Dibutylamino-7-(o-chloroanilino)fluoran.

3-dibutylamino-7-(0-fluoroanilino)fluorane, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-7nilinofluorane.

3-diethylamino-6-methyl-7-anilinofluorane, 3-(N-isoacyl-N-ethyl)amino-7-(0
-chloroanilino)fluoran, 3-(N-hexyl-N-methyl)amino-7-(O-
chloroanilino)fluoran 3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluorane.

Benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane.

3-(2'-hydroxy-41-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-( 2'-Methoxy-5'-nitrophenyl)phthalide.

3-(2'-Hydroxy-4'-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)fluoran.

3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluorane.

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

3-(N-ethyl-p-toluidino)-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)fluoran, 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, a specific example of the basic leuco dye preferably contained in the high temperature side coloring layer is 3-diethylamino-7-chlorofluoran.

Examples include 3-diethylamino-6-methyl-7-chlorofluoran, 3-cyclohexylamino-6-chlorofluoran, and 3-diethylaminobenzo[α]fluorane.

In the present invention, the high temperature side thermosensitive coloring layer may contain an acidic leuco dye, for example, an acylated lactone type or sultone type leuco dye as shown below.

In the present invention, examples of the color developer for the leuco dye in the high-temperature coloring layer and the low-temperature coloring layer include N,N'-diphenylthiourea, N-p-ethylphenyl-N'-phenylthiourea, N-P-butyl Phenyl-N'-phenylthiourea, N,N'-di1rchlorophenylthiourea,
N,N'-di-p-chlorophenylthiourea, N,N'
-G-san-trifluoromethylphenylthiourea, N
, N'-di■-methylphenylthiourea, 4.4'
-isopropylidene diphenol.

4.4'-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-t, ert-butylphenol), 4.4'-5ec-butylidene diphenol, 4.4'-cyclohexylidene bis(2-methylphenol), 4-t, ert,-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-tart-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, p
-Benzyl hydroxybenzoate, P-chlorobenzyl p-hydroxybenzoate, 〇-chlorobenzyl p-hydroxybenzoate, P-methylbenzyl p-hydroxybenzoate, n-octyl P-hydroxybenzoate,
Benzoic acid, zinc salicylate, 1-hydroxy-2-naphthoic acid, 2-hydroxy-6-naphthoic acid, zinc 2-hydroxy-6-naphthoate, 4-hydroxydiphenylsulfone, 4-hydroxy-4'-chlorodiphenylsulfone , bis(4-hydroxyphenyl) sulfide,
0-sulfophthalimide, 5-isopropyl-〇-sulfophthalimide, 5-7-butyl-〇-sulfophthalimide, 5-octyl-0-sulfophthalimide 4,4'
-thiobis(3-methyl-6-t-butylphenol) and the like are used.

In the present invention, the coloring system in the first thermosensitive coloring layer is not particularly limited, and in addition to the leuco system described above, various systems such as those shown below can be used.

(a) Combination of long-chain aliphatic iron salts such as ferric stearate and ferric myristylate with phenols such as gallic acid and ammonium salicylate.

(b) Organic acid heavy metal salts such as nickel, cobalt, lead, copper, iron, mercury, and silver salts such as acetic acid, stearic acid, and palmitic acid, and alkaline earth metals such as calcium sulfide, strontium sulfide, and potassium sulfide. A combination with a sulfide or a combination of the organic acid heavy metal salt with an organic chelating agent such as S-diphenylcarbazide or diphenylcarbazone.

(c) Heavy metal sulfates such as silver, lead, mercury, thorium sulfates, Na-tetrathionate, sodium thiosulfate,
In combination with sulfur compounds such as thiourea.

(d) a fatty acid ferric salt such as ferric stearate;
Combination with aromatic polyhydroxy compounds such as 3,4-dihydroxytetraphenylmethane.

(e) A combination of an organic noble metal salt such as silver oxalate or mercury oxalate and an organic polyhydroxy compound such as polyhydroxy alcohol, glycerin, or glycol.

(f) Combinations of organometallic salts such as silver behenate and silver stearate and aromatic organic ring-forming agents such as protocatechuic acid, spiroindane, and hydroquinone.

(g) A combination of an aliphatic ferric salt such as ferric pelargonic acid or ferric laurate and a thiocetyl-rubamide or isothiocetyl-rubamide derivative.

(h) A combination of an organic acid lead salt such as lead caproate, lead pelargonate, or lead behenate and a thiourea derivative such as ethylenethiourea or N-dodecylthiourea.

(S) A combination of a higher fatty acid heavy metal salt such as ferric stearate or copper stearate and zinc dialkyldithiocarpanate.

(n) Those that form oxazine dyes, such as the combination of resorcinol and nitroso compounds.

(l) Combination of aromatic diazo compound and coupler.

(w) Combination of formazan compound and metal salt.

In the present invention, in order to bond and support each heat-sensitive coloring layer and decolorizing agent layer on a support, various commonly used binders can be used as appropriate.1For example, polyvinyl alcohol, starch and its derivatives, methoxy Cellulose derivatives such as cellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer , styrene/maleic anhydride copolymer alkali salt, isobutylene maleic anhydride copolymer alkali salt,
In addition to water-soluble polymers such as polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride/vinyl acetate copolymer, and Latex such as butyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc. can be used.

In addition, in the present invention, each heat-sensitive color forming layer and color erasing agent layer may contain additional auxiliary additives, such as fillers, surfactants, thermofusible It can be caused by using a sexual substance (or lubricant) etc. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. , urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, and other organic fine powders. Examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts. In addition, various waxes, fasteners of aromatic carboxylic acids and amines, phenyl benzoate, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalate, higher ketones, and other thermofusible organic materials. Examples include compounds having a melting point of about 50 to 200°C.

In order to obtain the two-color heat-sensitive recording material of the present invention, a color-forming dye, a color developer, a decolorizer, a binder, etc. are dispersed or dissolved on one side of a support such as paper, synthetic paper, or plastic film. It can be obtained by applying a liquid, drying it, and repeating the process. When further laminating on top of the coated layer, it is necessary to pay close attention to the solubility and releasability of the layer so that the lower layer does not mix with the upper layer. Further, after coating and drying, the upper layer may be applied after calendering. The amount of paint deposited on the high temperature coloring layer is 0.3g/rrr~1, Og/rd
The amount of decolorizing agent applied (coating amount) is suitably 0.5 to 5 g/rd, and a thermofusible substance or filler may be added as necessary.

Furthermore, it is preferable that the amount of the dye adhered to the low-temperature coloring layer is large in order to increase the density, but it is preferable that it is small in order to enhance the decoloring effect and to reduce costs.Usually, the amount of dye adhered is 0 .2 g/nl' to 0.8 g/rrr is preferred. The ratio of dye to color developer is preferably 1:1 to 1:5 by weight. When providing a protective layer, the amount of adhesion is 0.5g/-~
5.0g/proof is preferred.

〔effect〕

The two-color heat-sensitive recording material of the present invention has a high low-temperature color density and high-temperature color sensitivity by providing an intermediate layer of a leuco dye or a color-developing substance between the decoloring layer and the second thermosensitive color-forming layer. It is a two-color heat-sensitive recording material with excellent storage stability of low-temperature colored images.

[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 dispersion liquid was prepared by dispersing the following compositions using a sand glider.

[A□liquid]

3-diethylamino-7-chlorofluorane (red dye)
10 parts polyvinyl alcohol 10% aqueous solution 1011 water
30 parts (Liquid A2) 3-dibutylamyl-7-(o-chloroanilino)fluoran (black dye) 10 parts Polyvinyl alcohol 10% aqueous solution 10 Water

30〃[B□Liquid] 4.4'-dihydroxydiphenylsulfone 30 parts polyvinyl alcohol 10% aqueous solution 3Qzt water
90
[Bz solution] 3.3-Dichlorodiphenylthiourea 35 parts Polyvinyl alcohol 10% aqueous solution 30 Water
90〃
[Liquid C] Silica powder 20 parts Zinc stearate 5 n Ethylene bis stearamide 'lQn Polyvinyl alcohol 10% aqueous solution 22.51F water
112.5#
(Liquid D1) Silica powder 20 parts Zinc stearate 5 P-benzylbiphenyl 20 10% polyvinyl alcohol water m liquid 22.51F water
112.5# [Liquid E] Polyvinyl alcohol 10% aqueous solution 20 parts Silica fine particles 0.5 Zinc stearate 0.1 Water
10〃[F
Liquid] N,N'-isophthaloyldi(N-cyclohexyl-
N-methylamide) 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water
6
0 Next, [Ai solution]: (B1 solution): [C solution] = 1:
They were mixed at a ratio of 1:1, and the first heat-sensitive coloring layer coating solution was added to CAz solution]: (Bz solution): (D 1 solution) = 1:
A second heat-sensitive coloring layer coating solution was prepared by mixing at a ratio of 1:1.5. The first heat-sensitive coloring layer coating solution was coated on 42g/rrr high-quality paper with a leuco dye adhesion amount of 0. After applying and drying it so that it has a coating weight of sg/bo, and then forming a decoloring layer and an intermediate layer using [liquid F] and liquid CBz so that the dry adhesion amounts are 3 g/rrr and Ig/rrr, respectively, A second thermosensitive coloring layer coating solution was applied and dried so that the amount of leuco dye deposited was 0.35 g/rrr to form a second thermosensitive coloring layer.

Finally, use [Liquid E] on top of this to reduce the dry adhesion amount to about 2.
g/rrr to form a protective layer.

A two-color heat-sensitive recording material of the present invention was prepared by calendering the surface.

Comparative Examples 1 and 2 A two-color heat-sensitive recording material of Comparative Example 1 was prepared in the same manner as in Example 1 except that the intermediate layer was removed (Comparative Example 1).

Also, instead of the intermediate layer [Liquid B2] in Example 1, [C
Comparative Example 2 was carried out in the same manner except that the intermediate layer was formed using
A two-color heat-sensitive recording material was prepared.

Example 2 Instead of the intermediate layer made of [Bz liquid] in Example 1, (
A two-color heat-sensitive recording material of Example 2 was prepared in the same manner except that an intermediate layer was formed using [Liquid A].

Next, these two-color heat-sensitive recording materials were printed at 0.61/m2 using a printing simulator with a 7 dot/m line head.
dat, sub-scanning speed of 7.71 ine/am, and one line recording time of 10 m5 ec, and after performing a color development test by varying the pulse width, a preservability test was performed. Its contents are as follows.

(1) Maximum black color development density...highest density in the black color range (low temperature color development), based on Macbeth densitometer RD-514, filter rvratten-106 (2) Red color development sensitivity (high temperature color development sensitivity)...color development In terms of characteristics, if it develops a clear red color, it is a red filter (Wraeten-25).
If you measure it with this filter, it will be a low value, so if you measure it with this filter, the thermal head energy will be 0.25 or less.

(3) Black color image storage stability: This indicates the density of the 1.0 color area before the test after the sample subjected to the color development test was left at 40° C. and 90% RH for 24 hours.

Table 1 shows the above evaluation results.

Table 1 As seen from Table 1, the two-color heat-sensitive recording material of the present invention is
It can be seen that the black color density, high temperature color sensitivity, and black color image storage stability are superior to conventional two-color heat-sensitive recording materials without an intermediate layer or having an intermediate layer of a hook-like substance.

Claims (1)

[Claims] (1) On one side of the support, first and second heat-sensitive coloring layers each having different coloring heat energy and producing different tones are stacked one on top of the other, with the one with smaller coloring heat energy being the upper layer. , and between the two heat-sensitive coloring layers,
In the two-color thermosensitive recording material provided with a decoloring layer containing a decoloring agent as a main component for the coloring system of the second thermosensitive coloring layer, a leuco dye is provided between the decoloring layer and the second thermosensitive coloring layer. A two-color heat-sensitive recording material characterized in that it has an intermediate layer containing either one of a color developer and a color developing substance as a main component.