JPS6362780A - Multicolor thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a multicolor thermal recording material excellent in color separability and generating no color mixture, by using a specific compound as a decolorizing agent. CONSTITUTION:In a multicolor thermal recording material wherein a plurality of thermal color forming layers forming colors having different hues are provided on a support and an intermediate layer for isolating a decolorizing layer and an adjacent layer is provided between the thermal color forming layers if necessary, a compound represented by formula (I) (wherein R is an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group and A is an aryl group) is contained in at least one layer among the above-mentioned layers. For example, a two-color thermal recording material can be obtained by repeating a process for coating a support with a solution having a color formable dye, coupler, the decolorizing agent and a binder etc. dispersed or dissolved therein and drying the coating layer formed. In the case of lamination, it is necessary to sufficiently pay attention to solubility of the respective layers so as to prevent the mixing of a lower layer with an upper layer and the dye adhesion amount of a high temp. color forming layer is set to 0.3-1.0g/m<2>, the adhesion amount of the decolorizing agent of the decolorizing layer is set to 1.0-10g/m<2> and that of a low temp. color forming layer is set to 0.2-0.5g/m<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical 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.

[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 'V! The recording material includes 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 layer, and a color developer (color-forming agent) that reacts with the leuco dye when heated to form a color. Those containing auxiliary agents) are often used because they have a clear color tone and cause 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 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 decolorizes the low-temperature color-forming layer, only the color tone of the high-temperature color-forming layer is obtained without color mixture of the color tone of the low-temperature color-forming layer.

As a specific example of these, the former is
Publication No. 9, Special Publication No. 49-4342, Special Publication No. 49-27
No. 708, JP-A-48-86543, JP-A-4
9-65239, etc., and the latter is described in Japanese Patent Publication No. 17865-1986 and Japanese Patent Publication No. 50-178.
Publication No. 66, Special Publication No. 51-29024, Special Publication No. 5
These are disclosed in Japanese Patent Application Laid-open No. 1-87542, Japanese Patent Application Laid-open No. 18048-1982, and Japanese Patent Application Laid-open No. 47843-1983, respectively.

However, in the case of the former multicolor thermosensitive recording paper,
During high-temperature color development, the color tone that can be specifically achieved is red-black because the color is mixed with the color tone of the low-temperature color development layer.

The drawback is that high-temperature color tones such as blue-black are limited to strong black threads. On the other hand, in the case of the latter multicolor thermosensitive recording paper, the combination of one color tone can be freely selected, but when coloring at high temperatures, it is necessary to provide a decoloring layer containing a decoloring agent to decolor the low temperature coloring layer. There is. 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.

〔the purpose〕

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.

〔composition〕

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:

(In the formula, R represents an alkyl group, a cycloalkyl group, an aralkyl group, or an aryl group, and A represents an aryl group.) In the present invention, a plurality of heat-sensitive coloring layers that develop colors in different tones are provided on a support. In a multicolor heat-sensitive recording material, in which a decoloring layer and an intermediate layer for isolating an adjacent layer are provided between each heat-sensitive coloring layer as necessary, at least one of the layers contains a compound represented by the above general formula (1). 1 because it contains
It is possible to obtain a multicolor heat-sensitive recording material that has excellent color separation properties and does not cause color mixture.

The compound of general formula (1) used in the present invention is usually
It is a white powder that is sparingly soluble in water and can be used as a decolorizing agent, but it can also be used in combination with other commonly used decolorizing agents. In addition, the usage amount can be selected as appropriate, but 1.0g/
rrr～5. Og/m is appropriate.

Specific examples of the compound of general formula (1) include the compounds shown below.

N,N'-diphenyl-N-o-toluoyl-P-phenylene-diamine, N,N'-diphenyl-N-m-toluoyl-P-phenylene-diamine, N,N'-diphenyl-N-P-toluoyl -P-phenylene-diamine, N,N'-dinaphthyl-N-cyclohexylcarbonyl-P-phenylene-diamine, N,N'-dinaphthyl-N-benzoyl-P-phenylene-diamine, N,N'- Dinaphthyl-N-P-anisoyl-P-phenylene-diamine, N,N'-diphenyl-N-naphthoyl-P-phenylene-diamine, The leuco dyes used in the heat-sensitive coloring layer in the present invention can be applied alone or in combination of two or more. However, as such leuco dyes, those applied to this type of heat-sensitive material can be arbitrarily applied, such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, indolinophthalene-based, etc. Leuco compounds of lido-based dyes are preferably used. Specific examples of such leuco dyes include those shown below.

3.3-bis(P-dimethylaminophenyl)-phthalide, 3.3-bis(ρ-dimethylaminophenyl)-6-cyphthylaminophthalide (also known as crystal violet lactone), 3.3-bis(p- dimethylaminophenyl)-6-diethylaminophenyl.

3.3-bis(P-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7 - cyphthyl 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-ethylamino)-6-methyl-7-anilinofluorane.

3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(N-(3'-trifluoromethylphenyl)
amino)-6-ethylaminofluorane.

2-(3,6-bis(diethylamino)-9-(o-
Chloranilino) 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-7-7anilinofluorane.

3-(N,N-diethylamino)-5-dimethyl-7-(
N.

N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2'- 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)methylaminofluoran, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(0-methoxycarbonylphenylamino)fluoran.

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

3-diethylamino-7-piperidinofluoranylethylamino)fluorane, 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, 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, 4.47-isopropylidene bis-
(0-cresol), 4,4'-isopropylidenebis(o tert-butylphenol), 4.4'
-isopropylidene-bis(0-chlorophenol),
4,4'-cyclohexylidene bisphenol, 4,
4'-bisphenol sulfone, 4-hydroxy-47
-chloro-diphenylsulfone, 4-hydroxy-4'
-isopropoxydiphenylsulfone, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, p-hydroxybenzoic N4p-chlorobenzyl, salicylic acid anilide, salicylic acid (0-chloroanilide), salicylic acid (n-trifluoromethylanilide) ),
Dimethyl 4-hydroxyphthalate, 2-hydroxy-3
- naphthoic acid, benzyl 2-hydroxy-3-naphthoic acid, 2-hydroxy-3-naphthoic acid anilide, zinc 2-hydroxy-3-naphthoic acid, zinc chloride/antipyrine complex, methylenebis-(oxyethylenethio)diphenol, 4-hydroxyacetophenone, novolac type phenol resin, novolac type phenylphenol resin, diphenylthiourea, di(m-chlorophenyl)thiourea, di(+m-h methylphenyl)thiourea, etc.

In the present invention, in order to bind and support the leuco dye and the color developer on the support, various conventional binders can be used as appropriate.1 For example, polyvinyl alcohol,
Starch and its derivatives, methoxycellulose, hydroxyethylcellulose.

Cellulose derivatives such as carboxymethylcellulose and methylcellulose ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic ester copolymer, acryl amide/acrylic ester/methacrylic acid ternary copolymer, styrene /maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide,
In addition to water-soluble polymers such as sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride/vinyl acetate copolymer, polybutyl methacrylate, Latex such as 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 ( or lubricant), etc. can be used in combination. In this case, as a filler.

For example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate,
Examples include fine inorganic powders such as clay, talc, and surface-treated calcium and silica, as well as fine organic powders such as urea-formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin. As a fusible substance,
For example, in addition to higher fatty acids or their esters, amides, or metal salts, various waxes, feedstocks of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, 3,4-epoxy-hexahydrophthal Examples include dialkyl acids, higher ketones, and other heat-fusible 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 color erasing 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 applied after calendering. The amount of dye attached to the high-temperature coloring layer is 0.3 g/rrl to 1.0 g/&,
The amount of decolorizing agent attached to the decolorizing agent layer is 1.0g/rrl to 10g
/rrr, and the amount of the low-temperature coloring layer deposited is 0.2g1, as described above, when the leuco dye is deposited as a dry product.
rd~0.5gIrd. Horo II! When a layer is provided, the amount of adhesion is 0.5g/r/~5. When providing an intermediate layer between the decoloring agent layer and the low-temperature coloring layer and/or the decoloring agent layer and the high-temperature coloring layer, the former is preferably 0.5 g/M to 0.0g/m.
5.0g/rd is preferable, and the latter is Ig/rrr~Lo
g/rf 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 can clearly express a plurality of tones formed by using the compound of the general formula (1) as a decoloring agent without mixing colors, It also provides a multicolor image with excellent color matching.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Please note that the parts and percentages shown below are based on headquarters standards.

Examples 1 to 3 The following components were each pulverized and dispersed for 24 hours using a ball mill to prepare dispersions A to D.

[Dispersion liquid-A]

10% hydroxyethylcellulose aqueous solution 20〃water
6
0 [Dispersion-B] 3.3-dichlorophenylthiourea lO part N
-Stearylbenzamide 10〃Calcium carbonate 15I! Polyvinyl alcohol (10% aqueous solution) 30 water
40〃[Dispersion-〇] 10% hydroxyethyl cellulose aqueous solution 20〃Water
6
0 [Dispersion liquid-〇] 3.3-Dichlorophenylthiourea 10 parts Calcium carbonate 10 parts Polyvinyl alcohol 10% aqueous solution 20 Water
601
I [Dispersion-E] Crystal violet lactone (blue) 20 parts 10%
Hydroxyethyl cellulose aqueous solution 20! I water
6Q
u [Dispersion-F] Bisphenol A 10 parts Calcium carbonate 10H2O% hydroxyethylcellulose aqueous solution ISn water
65 10 parts of dispersion A prepared as above, 860 parts of dispersion,
30 parts of water were each taken and mixed and stirred to obtain a thermosensitive color forming liquid for low temperature use. Separately, 1 part of Dispersion CIO, 70 parts of Dispersion D and 20 parts of water were each taken and 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 aqueous solution 2Qn water
60〃
Next, on a commercially available high-quality paper with a basis weight of about 52 g/rrr, the high temperature thermosensitive coloring layer forming liquid (coating weight when drying 5 g/rrr),
A decoloring agent layer forming liquid (coating area when drying: 3 g/n()) and a low-temperature thermosensitive coloring layer forming liquid (coating area when drying: 4 g/rrr) are applied and dried in sequence, and then calendering is performed to achieve a smoothness of 500 to 1000 seconds. Thus, multicolor heat-sensitive recording materials of Examples 3 to 3 of the present invention were prepared.

Comparative Example 1 In Example 1, N,N',N'-triphenylguanidine was used instead of N,N'-diphenyl-N-P-toluoyl-P-phenylenediamine in the decolorizer layer forming liquid. A comparative heat-sensitive recording material was prepared in the same manner as in Example 1.

Comparative Example 2 In Example 1, N,N'-diphenyl-N'-cyclohexylguanidine was used instead of N,N'-diphenyl-N-P-toluoyl-p-phenylenediamine in the decolorizer layer forming liquid. A heat-sensitive recording material for comparison was prepared in the same manner as in Example 1 except for the above.

Table 1 The multicolor thermosensitive recording materials of Examples and Comparative Examples obtained as described above were tested for dynamic coloring characteristics using a G-m facsimile test machine.

The test machine was an 8 dot/m manufactured by Kenko Electronic Parts Co., Ltd.
m thermal head, the heating element resistance is approximately 400Ω/dot, and the color development test was performed at a main scanning recording speed of 20m5.
ec/1ine, sub-scanning 3.85 (11mm,
Platen suppression 3.0kg/ffl, head input 0.61
/ Dot conditions. The coloring energy was 1.0 mJ for the low temperature coloring layer and 3.3mJ for the high temperature coloring layer.

In addition, a Macbeth densitometer was used to measure the concentration.

As a result of the test, in Examples 1 to 3, the three constituent colors were clearly separated and developed, whereas in Comparative Example 1.2, the three constituent colors exhibited mixed color.

Claims (1)

[Claims] (1) A multicolor thermosensitive recording material having a structure in which a plurality of heat-sensitive coloring layers that develop colors in different tones are laminated and containing a decoloring agent, characterized in that a compound represented by the following general formula is used as the decolorizing agent. A multicolor heat-sensitive recording material. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents an alkyl group, cycloalkyl group, aralkyl group, or aryl group, and A represents an aryl group.)