JPH04129790A - Multicolor thermal recording material - Google Patents

Abstract

PURPOSE:To sharply express an image without generating the color mixture of a plurality of hues by laminating a plurality of thermal color forming layers developing different hues and using a specific compound as the color erasing agent contained in a multicolor thermal recording material. CONSTITUTION:In a multicolor thermal recording material wherein a plurality of thermal color forming layers developing different hues are provided on a support such as paper and an intermediate layer for isolating a color erasing layer and the adjacent layer is provided between the respective thermal color forming layers, a compound represented by general formula (I) or (II) (wherein n is an integer of 2-6) is added to at least one layer among the respective layers as a color erasing agent. By this method, the multicolor thermal recording material excellent in color separability and generating no color mixture can be obtained. As a compound represented by the general formula (I), for example, there is N, N'-diphenyl-N, N'-dicinnamoyl-o- phenylenediamine and, as a compound represented by the general formula (II), for example, there is l, 3-bis(N-cinnamoylpiperidyl)propane. As a leuco dye adapted to the thermal material, for example, there is leuco compound of a triphenylmethane type dye, for example, 3, 3-bis(p-dimethylaminophenyl)phthalide. As a developer reacting with said leuco dye at the time of heating to develop a color, a phenolic substance or org. or inorg. acidic substance is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multicolor heat-sensitive recording material, and more particularly to a multicolor heat-sensitive recording material formed by laminating a plurality of heat-sensitive coloring layers having different color tones.

[Conventional technology]

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.

Such 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 color-forming M, and a color-forming material that reacts with this leuco dye when heated. Those containing a color developer (color development aid) are often used because they have a clear color tone 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 and documents, but also for recording various information from computers, facsimiles, telex machines, etc., and output records from measuring machines. Depending on the field of use or the purpose of the record, the coloring of the area (
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 stacking two types of high-temperature and low-temperature coloring layers that develop different tones using different coloring heat energies on a support, and can be roughly divided into the following two types: Divided into types. One is to mix the color with the color tone of the low temperature coloring layer when coloring the high temperature coloring layer to obtain a color tone different from the coloring tone of the low temperature coloring layer, and the other is to color the high temperature coloring layer. In this case, by using a decoloring agent that decolors the low temperature coloring layer, only the color tone of the high temperature coloring layer is obtained without color mixture of the coloring tone of the low temperature coloring layer. As specific examples of these, the former is disclosed in Japanese Patent Publication No. 49-69,
JP 49-4342, JP 49-27708, JP 48-865/13, JP 49-6
523! ], and the latter is described in Japanese Patent Publication No. 17865, Japanese Patent Publication No. 50-17866, etc.
Publication No. 51-29024, Special Publication No. 51-29024, Publication No. 51-29024
These are disclosed in JP-A No. 87542, JP-A-50-18048, and JP-A-53-47843, 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 coloring at high temperatures, a decoloring layer containing a decoloring agent that decolors the low temperature coloring layer is added. It is necessary to provide It has been proposed to use aliphatic amines, aromatic amines, polyethers, etc. as such decolorizing agents. However, these decoloring agents have the disadvantage that they do not sufficiently decolor the coloring layer, resulting in mixed colors.

[Problem to be solved by the invention]

An object of the present invention is to overcome the problems of the prior art described above, and to provide a multicolor thermosensitive recording material that has excellent color separation properties and does not cause color mixing.

[Means to solve the problem]

According to the present invention, in a multicolor thermosensitive recording material having a laminated structure of a plurality of heat-sensitive coloring layers that develop colors in different tones and containing a decoloring agent, the decoloring agent is expressed by the following general formula (1).
A multicolor heat-sensitive recording material is provided which is characterized by using a compound represented by A multicolor heat-sensitive recording material is provided, which is characterized in that a compound represented by the following general formula (+1) is used as the decoloring agent.

In formula C, n represents an integer of 2 to 6. ) In the present invention, a multicolor thermosensitive material has a plurality of thermosensitive coloring layers that develop colors in different tones on a support, and if necessary, an intermediate layer is provided between each thermosensitive coloring layer to separate a decoloring layer and an adjacent layer. In the recording material, at least one of the layers contains a compound represented by the above general formula (1) or (If), so that a multicolor thermosensitive recording material that has excellent color separation properties and does not cause color mixing can be obtained. Obtainable.

The compound of general formula (1) or (II) used in the present invention usually has a melting point of 80 to 300°C and is dissolvable in water,
Although it can be used as a decolorizing agent, it can also be used in combination with other conventional decolorizing agents. Further, the amount used can be appropriately selected, but 1.0 g/rn'-5.0 g/m is suitable.

Specific examples of the compound represented by the general formula (I) include the compounds shown below.

N,N'-diphenyl-N,N'-dicinnamoyl 0
-phenylenediamine, N,N'-dimethyl-N,N'-dicinnamoyl 〇-
Phenylenediamine, N,N'-diethyl-N,N'-dicinnamoyl〇-
Phenylenediamine, N,N'-dicyclohexyl-N,N'-dicinnamoyl〇-phenylenediamine, N,N'-diphenyl-N,N'-dicinnamoyl m
-phenylenediamine, N,N'-dimethyl-N,N'-dicinnamoyl m-
phenylenediamine, N,N'-diethyl-N,N'-dicinnamoyl m-
Phenylenediamine, N,N'-dicyclohexyl-N, N'-dicinnamoyl m-phenylenediamine, N,-〇'-diphenyl-full, N'-dicinnamoyl-p-phenylenediamine, N,N'-dimethyl-N, N'-Dicinnamoyl p-
phenylenediamine, N,N'-diethyl-N,N'-dicinnamoyl-P-
phenylenediamine, N,N'-dicyclohexyl-N,N'-dicinnamoyl-ρ-phenylenediamine, etc.

Specific examples of the compound represented by general formula (II) include:
Compounds as shown below can be mentioned.

1.3-bis(N-cinnamoylpiperidyl)propane, 1.4-bis(N-cinnamoylpiperidyl)butane.

1.6-bis(N-cinnamoylpiperidyl)hexane, 1.2-bis(N-cinnamoylpiperidyl)ethane, etc.

Note that two or more of these compounds can be used in combination.

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-dimethyl aminophenyl)-6-dibutylaminophenyl, 3.3-bis(P-dimethylaminophenyl)-6-chlorphthalide, 3.3-bis(P-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlor Fluoran, 3-dimethylamino-5,7-dimethylfluoran, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-chlorochlorofluorane, 3-(N-p-tolyl-N -ditylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(~-(3'-trifluoromethylphenyl)amino)-6- Dinithylaminofluorane, 2- (3,6
-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)
Fluorane.

3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran.

3-N-methyl to N-7mylamino-6-methyl-7-
Anilinofluorane, 3-N-Methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-anilinofluorane.

3-(N,N-diethylamino)-5-methyl-7-(
(2N-dihencylamino)fluoran, bennyylleucomethylene blue 6'-chloro-8'-methquin-henzoindolinopyrylospirane, 6'-bromo-3'-methoxy-benzointrinopyrylosbilane, 3-(2 '-Hydroxy-4'-dimethylaminophenyl)-3-(2'-methphon-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'-methoxy4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluoran.

3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-gloro-7-(N-pensylutetrifluorocomethylanilino)fluorane, 3-pyrrolidino-7-(di-P-thalolphenyl)methyl Aminofluorane, 3-diethylamino-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-(ρ-n
-butylanilino)fluorane, 3-(N-benzyl=N~ncrohexylamino)-5
, 6-penzo 7-α-naphthylamino-4'bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-Henzofluorane etc.

In the present invention, various electron-accepting substances are used as the color developer that reacts with the leuco dye to develop color when heated, such as phenolic substances, organic or inorganic acid substances, or metal salts thereof, aromatic amide compound,
Examples include aromatic urea compounds, and specific examples thereof are shown below.

Clay, activated clay, activated silica, boric acid, zinc oxide, zinc chloride, aluminum chloride, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis-(0-cresol), 4,4'-isopropylene Redenbis (o-tert~butylphenol), 4.4'
-isopropylidene-bis(0-chlorophenol)
, 4,4'-cyclohexylidene bisphenol, 4
, 4'-bisphenol sulfone, 4-hydroxy-4
'-Chloro-diphenylsulfone, 4-hydroxy-4
'-isopropoxydiphenyl sulfone, isopropyl p-hydroxybenzoate, benzyl ρ-and troxybenzoate, p-hydroxybenzoyl-chlorobenzyl, salicylic acid anilide, salicylic acid-(0-chloroanilide), salicylic a-(n-4 -lifluoromethylanilito)
, dimethyl 4-hydroxyphthalate, 2-hydroxy-
3-naphthoic acid, benzyl 2-hydroxy-3-naphthoic acid, 2-hydroxy-3-naphthoic acid anilide, 2-
Zinc hydroxy-3-naphthoate, zinc chloride/antipyrine complex, methylenebis-(oxyethylenethio)duphenol, 4-hydroxyacetophenone, novolak-type phenolic resin, novolak-type phenylphenol resin, diphenylthiourea, di(m-chlorophenyl)thio Urea, di(m-trifluoromethylphenyl)thiourea, 1,7-bis(4-hydroxyphenylthio)-3,
5-dioxaheptane etc.

In the present invention, in order to bind and support the leuco dye and color developer on the support, various commonly used binders can be used as appropriate, such as polyvinyl alcohol, starch and its derivatives, methoxycellulose, hydroxyl, etc. Cellulose derivatives such as ethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid 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, in addition to the leuco dye and color developer, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances, etc. (or lubricant) etc. can be used in combination. 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. In addition, organic fine powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin can be mentioned. Examples of thermofusible substances include higher fatty acids or their esters, amides, or metal salts. In addition, various waxes, condensates of aromatic carbonic acids and amines, phenyl benzoate, higher linear glycols, dialkyl 3,4-epoxy-hexahydrophthalate, benzyl ρ-benzyloxybenzoate, higher ketones , P-benzylbiphenyl,
Examples include other thermofusible organic compounds having a melting point of about 50 to 200°C.

For example, in order to obtain a two-color heat-sensitive recording material according to the present invention, a liquid in which a color forming dye, a color developer, a decolorizing agent, a binder, etc. are dispersed or dissolved on a support such as paper, synthetic paper, or plastic film is used. It can be obtained by applying it, drying it, and repeating it. 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 coated after being subjected to gear rendering treatment. The amount of dye attached to the high-temperature coloring layer is 0.3 g/m to 1.0 g/m, and the amount of decoloring agent attached to the decoloring agent layer is 1.0 g/rd to 10 g/m.
rr? As mentioned above, the amount of the low-temperature coloring layer deposited is 0.2 g/m when the leuco dye is deposited as a dry product.
~0.5g/rrr. The amount of coating on the nozzle on which the protective layer is applied is 0.5g/rr? ~5. Og/mF is preferred. When providing an intermediate layer between the decoloring agent layer and the low-temperature coloring layer or between the decoloring agent layer and the high-temperature coloring layer, the former is 0.5 g/rr.
f~5, Og/rr? is preferred, the latter being Ig#
r? ~log/rn' is preferred.

Furthermore, by further increasing the number of thermosensitive coloring layers in the same manner as described above, it is also possible to obtain a multicolor thermosensitive recording material having three or more colors.

〔effect〕

The multicolor heat-sensitive recording material of the present invention has the above-mentioned structure, and uses the compound of the general formula (N or (II)) as a decoloring agent to clearly express a plurality of color tones without mixing colors. It can produce multicolor images with excellent brown color separation.

〔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.

Examples 1 to 7, Comparative Examples 1 to 4 Each of the following components was pulverized and dispersed for 24 hours using a ball mill to prepare Dispersions A to D.

[Dispersion liquid-8]

Water 0n [Dispersion-B] 3,3-dichlorophenylthiourea 10 parts N-
Stearyl heshizuamito 10! ! Calcium charcoal 15n polyvinyl alcohol (10% aqueous solution) 30II water
40〃[Dispersion-〇] 3-diethylamino-7-thalolfur 20 parts Oran (red) 10% hydroxyethyl cellulose aqueous solution M 20n water
6Qn [Dispersion-D] Bisphenol 5 10 parts Calcium carbonate 10% polyvinyl alcohol aqueous solution 2011 Water
60
1 part or more of dispersion A prepared as above, 10 parts, dispersion 8
60 parts were mixed and stirred to obtain a low temperature heat-sensitive color forming liquid. On the other hand, 10 parts of Dispersion C and 70 parts of Dispersion D were mixed and stirred to obtain a thermosensitive coloring layer forming liquid for high temperature coloring.

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

[Decolorizer layer forming liquid]

Decoloring agent in Table-1 20 parts 10%
Polyvinyl alcohol water soluble fi 2Qn water

60.1 Next, on commercially available high-quality paper with a basis weight of about 52 g/m,
The above-mentioned high temperature thermosensitive coloring layer forming liquid (dry coating amount: 6 g/
rn'), erasing agent layer forming liquid (dry coating iL4g/m
'') and low-temperature thermosensitive coloring layer forming liquid (dry coating amount: 4 g
/m) was sequentially applied and dried to prepare a multicolor heat-sensitive recording material.

Table 1 The multicolor heat-sensitive recording materials of Examples and Comparative Examples obtained as described above were tested as follows.

■Image density Printing tester with thin film head made by Matsushita Electronics, head power 0.6υ/dot, 1 line recording time 10m
5/Q, scanning line density 8 x 7.7 doso/I+1m, the low temperature coloring layer prints with a pulse width of 1.0ms and the high temperature coloring layer has a pulse width of 2.2ms, and the print density and Macbeth densitometer RD-514 ( Filter Ratten-1,06)
It was measured with

■Residual rate The residual rate of low-temperature coloring during high-temperature coloring, expressed by the formula. However, in this measurement, a red film was used to measure the density of the blue portion (that is, the residual density of black density). The results are shown in Table-2.

Table 2 As shown above, it can be seen that the multicolor heat-sensitive recording material of the present invention has excellent coloring properties in the low-temperature coloring layer and significantly improved color erasing properties.

Claims (3)

[Claims] (1) In a multicolor thermosensitive recording material that has a structure in which a plurality of thermosensitive coloring layers that develop colors in different tones are laminated and also contains a decoloring agent, a compound represented by the following general formula (I) is used as the decolorizing agent. A multicolor heat-sensitive recording material characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 and R_2 represent an alkyl group, a cycloalkyl group, or an aryl group.) (2) In a multicolor thermosensitive recording material that has a structure in which a plurality of heat-sensitive coloring layers that develop colors in different tones are laminated and also contains a decoloring agent, a compound represented by the following general formula (II) is used as the decolorizing agent. A multicolor heat-sensitive recording material characterized by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, n represents an integer from 2 to 6.) (3) The multicolor heat-sensitive recording material according to claim (1) or (2), wherein the decolorizing agent represented by general formula (I) or general formula (II) has a melting point within the range of 80 to 300°C. .