JPH0717098B2 - Multicolor thermal recording material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a multicolor thermosensitive recording material, and more particularly to a multicolor thermosensitive recording material obtained by laminating a plurality of thermosensitive coloring layers having different color tones.

[Prior art]

The heat-sensitive recording material is one in which a heat-sensitive color forming layer capable of forming a color-formed 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. As such a conventional thermosensitive recording material, a kraton ring, a lactam layer, a thermosensitive coloring layer,
A colorless or light-colored leuco dye having a spiropyran ring (main coloring agent) and a developer that develops a color by reacting with this leuco dye when heated (coloring auxiliary agent) have a clear color tone and have a fogging effect. It is often used because it has few phenomena.

By the way, the thermosensitive recording material is not only used for copying books, documents, etc., because a colored image can be easily obtained only by heating it, but it is also used in various fields such as electronic calculators, facsimiles, telexes, etc. Depending on the recording application, it is desirable to be able to record the color of that part (display color) by changing it from the color of other parts, in order to display the necessary data and numbers more clearly depending on the purpose of recording. It is natural.

Recently, attempts have been made to obtain multicolor recording by utilizing the difference in heating temperature or the difference in thermal energy, and various multicolor thermosensitive recording papers have been proposed accordingly. The multicolor color thermosensitive recording paper is generally formed by stacking two kinds of high-temperature and low-temperature color-developing layers, which are colored in different colors with different color-developing heat energies, on a support. It is divided into types. One is to obtain a color tone different from the color tone of the low temperature color layer by mixing with the color tone of the low temperature color layer when the high temperature color layer is colored, and the other one is
When a high-temperature color-developing layer is colored, a decoloring agent that decolors the low-temperature color-developing layer is used to obtain only the color-developing color tone of the high-temperature color-developing layer without the color mixture of the low-temperature color-developing layer. As specific examples of these, the former are disclosed in Japanese Patent Publication No. 49-69 and Japanese Patent Publication No. 49-49.
-4342, JP-B-49-27708, JP-A-48-86543, JP-A-49-65239, etc., and the latter are described in JP-B-50-17865 and JP-B- 50-17866, Japanese Patent Publication No. 51-29024, Japanese Patent Publication No. 51-87542,
These are disclosed in JP-A-50-18048 and JP-A-53-47843, respectively.

However, in the case of the former color-developed thermosensitive recording paper,
In the case of high-temperature color development, the color tone that can be specifically realized to mix with the color tone of the low-temperature color layer is such that the high-temperature color tone such as red-black, blue-black, etc. is limited to a black type with a strong tone. There is. On the other hand, in the case of the latter multicolor color thermosensitive recording paper, the combination of coloring colors can be freely selected, but it is necessary to provide an erasing layer containing an erasing agent for erasing the low temperature coloring layer during high temperature coloring. There is. It has been proposed to use an aliphatic amine, an aromatic amine, a polyether or the like as such a decoloring agent. However, these decolorizing agents have a drawback that the decoloring layer is not sufficiently decolorized, resulting in color mixture.

〔Purpose〕

SUMMARY OF THE INVENTION It is an object of the present invention to provide a multicolor heat-sensitive recording material that overcomes the above-mentioned problems of the prior art and is excellent in color separation and does not cause color mixing.

〔Constitution〕

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

(In the formula, R represents an alkyl group, a cycloalkyl group, or an aryl group.) In the present invention, a plurality of thermosensitive color layers that develop different color tones are provided on the support, and if necessary, each thermosensitive color layer is provided between the thermosensitive color layers. In a multicolor thermosensitive recording material provided with an intermediate layer for separating an erasable layer and an adjacent layer, at least one layer of each layer contains a compound represented by the above general formula (I), which results in color separation. It is possible to obtain a multicolor heat-sensitive recording material having excellent properties and not causing color mixture.

The compound of the general formula (I) used in the present invention is usually
Although it is a white powder, it is hardly soluble in water and can be used as a decoloring agent, but it can also be used in combination with other conventional decoloring agents. The amount used can be appropriately selected, but 1.0 g / m ² ~
5.0 g / m ² is suitable.

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

1,3-bis (N-acetylpiperidine) propane, 1,3-bis (pivaloylpyrrolidine) propane, 1,3-bis (N-octanoylpiperidine) propane, 1,3-bis (N-lauroylpiperidine) ) Propane, 1,3-bis (N-cyclohexylcarbonylpyridyl)
Propane, 1,3-bis (N-benzoylpiperidyl) propane, 1,3-bis (Nm-trioylpiperidyl) propane, 1,3-bis (Np-trioylpiperidyl) propane, 1,3 -Bis (Np-anisoylpiperidyl) propane, 1,3-bis (N-stearoylpiperidyl) propane and the like.

The leuco dyes used in the present invention may be used alone or as a mixture of two or more, and as such leuco dyes,
What has been applied to this type of heat-sensitive material is arbitrarily applied, for example, triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, indolinophthalide-based dye leuco compounds 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-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6- Chlorofluorane, 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- (Np-tolyl-N-ethylamino) -6-methyl- -Anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluorane, 2- {3,6 -Bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoic acid lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluorane, 3-diethylamino-7- (o-chloroanilino) Fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane, 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, benzoyl leuco methylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrrolispirane, 6'-bromo-3'-methoxy-benzoindolino-pyrrolispirane, 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-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) fluorane, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluorane, 3 -(N-ethyl-p-toluidino) -7- (α-phenylethylamino) fluorane, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7- (α -Phenylethylamino) fluorane, 3-diethylamino-7-piperidi Fluoran sulfonyl ethylamino) fluoran, 3-diethylamino-7-piperidinocarbonyl fluoran, 2-chloro-3-(N-Mechirutoruijino) -7- (p
-N-butylanilino) fluorane, 3- (N-benzyl-N-cyclohexylamino)-
5,6-benzo-7-α-naphthylamino-4′-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino-
4 ', 5'-benzofluorane and the like.

In the present invention, various electron-accepting substances are applied as the color developing agent that reacts with the leuco dye when heated to develop it, and a phenolic substance, an organic or inorganic acidic substance or a metal salt thereof, Aromatic amide compound,
Examples thereof include aromatic urea compounds, and specific examples thereof will be shown below.

Clay, activated clay, activated silica, boric acid, zinc oxide, zinc chloride, aluminum chloride, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis- (o
-Cresol), 4,4'-isopropylidene bis (o-t
ert-butylphenol), 44'-isopropylidene-
Bis (o-chlorophenol), 4,4'-cyclohexylidene bisphenol, 4,4'-bisphenol sulfone, 4-hydroxy-4'-chloro-diphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, Isopropyl p-hydroxybenzoate, p-
Benzyl hydroxybenzoate, p-chlorobenzyl p-hydroxybenzoate, anilide silicylate, salicylic acid- (o-chloroanilide), salicylic acid- (n-trifluoromethylanilide), dimethyl 4-hydroxyphthalate, 2-hydroxy. -3-naphthoic acid, benzyl 2-hydroxy-3-naphthoate, 2-hydroxy-3-naphthoic acid anilide, 2-hinylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro -3- (N-methyltoluidino) -7- (p
-N-butylanilino) fluorane, 3- (N-benzyl-N-cyclohexylamino)-
5,6-benzo-7-α-naphthylamino-4′-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino-
4 ', 5'-benzofluorane and the like.

In the present invention, various electron-accepting substances are applied as the color developing agent that reacts with the leuco dye when heated to develop it, and a phenolic substance, an organic or inorganic acidic substance or a metal salt thereof, Aromatic amide compound,
Examples thereof include aromatic urea compounds, and specific examples thereof will be shown below.

Clay, activated clay, activated silica, boric acid, zinc oxide, zinc chloride, aluminum chloride, 4,4'-isopropylidene bisphenol, 4,4'-isopropylidene bis- (o
-Cresol), 4,4'-isopropylidene bis (o-t
ert-butylphenol), 4,4'-isopropylidene-
Bis (o-chlorophenol), 4,4'-cyclohexylidene bisphenol, 4,4'-bisphenol sulfone, 4-hydroxy-4'-chloro-diphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, Isopropyl p-hydroxybenzoate, p-
Benzyl hydroxybenzoate, p-chlorobenzyl p-hydroxybenzoate, anilide salicylate, salicylic acid- (o-chloroanilide), salicylic acid- (n-trifluoromethylanilide), dimethyl 4-hydroxyphthalate, 2-hydroxy-3. -Naphthoic acid, benzyl 2-hydroxy-3-naphthoate, zinc droxy-3-naphthoate, zinc chloride / antipyrine complex, methylenebis-
(Oxyethylenethio) diphenol, 4-hydroxyacetophenone, novolac type phenol resin, novolac type phenylphenol resin, diphenylthiourea,
Di (m-chlorophenyl) thiourea, di (m-trifluoromethylphenyl) thiourea type and the like.

In the present invention, in order to bond and support the leuco dye and the color developer on a support, various conventional binders can be appropriately used, and examples thereof include polyvinyl alcohol, starch and its derivatives, methoxycellulose and hydroxy. Cellulose derivatives such as ethyl cellulose, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, styrene / Maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, casein and other water-soluble polymers, polyvinyl acetate,
Polyurethane, styrene / butadiene copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride / vinyl acetate copolymer, polybutylmethacrylate, ethylene / vinyl acetate copolymer, styrene / butadiene / acrylic copolymer, etc. Latex can be used.

Further, in the present invention, together with the leuco dye and the color developer, if necessary, further auxiliary additives commonly used in this type of heat-sensitive recording material, for example, a filler, a surfactant, a heat-fusible substance ( Alternatively, a lubricant) or the like can be used in combination. In this case, as the filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, inorganic fine powder such as surface-treated calcium or silica, etc. , Urea-formalin resin, styrene / methacrylic acid copolymer, polystyrene resin, and other organic fine powders,
Examples of the heat fusible substance include, for example, higher fatty acids or esters, amides or metal salts, various waxes, condensates of aromatic carboxylic acids and amines, phenyl benzoate esters, higher linear glycols, 3,4- Examples thereof include epoxy-dialkyl hexahydrophthalate, higher ketones, and other heat-fusible organic compounds having a melting point of about 50 to 200 ° C.

For example, to obtain a two-color thermosensitive recording material according to the present invention,
It can be obtained by coating and drying a liquid in which a color-forming dye, a color developer, a decoloring agent, a binder, etc. are dispersed or dissolved on a support such as paper, synthetic paper, plastic film and the like, and repeating this. In the case of further laminating on the coated layer, it is necessary to pay sufficient attention to the solubility and the peelability of the layer so that the lower layer does not mix with the upper layer. Further, the upper layer may be applied after the coating and drying and the calender treatment. Dye deposition amount of the high-temperature coloring ^{layer, 0.3g / m 2 ~1.0g / m} 2, decolorizer adhesion amount of decolorizing agent layer is ^{1.0g / m 2 ~10g / m 2} , also low-temperature color-forming layer the amount of adhesion, as described above, with the leuco dye adhering as dry matter, is ^{0.2g / m 2 ~0.5g / m 2} . Adhesion amount of the case of providing the protective ^{layer, 0.5g / m 2 ~5.0g / m} 2 is preferred. If an intermediate layer between the color erasing agent layer and between the low-temperature color-forming layer and or decolorizer layer and the high-temperature color-forming layer, the former is preferably ^{0.5g / m 2 ~5.0g / m 2} ,
The latter 1g / m ² ~10g / m ² is preferred.

Further, by increasing the number of thermosensitive coloring layers in the same manner as described above, a multicolor thermosensitive recording material having three or more colors can be obtained.

〔effect〕

The multicolor heat-sensitive recording material of the present invention has the above-mentioned constitution, and it is possible to express clearly without mixing a plurality of color tones formed by using the compound of the general formula (I) as a decoloring agent, It also provides a multicolor image with excellent color separation.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples. The parts and% shown below are based on weight.

Examples 1 to 5 The following components were pulverized and dispersed in a ball mill for 24 hours to prepare dispersions A to D.

[Dispersion-A]

3- (N-ethyl-N-amylamino) -6-methyl-
7-anilinofluoran (black) 20 parts 10% hydroxyethyl cellulose aqueous solution 20〃 water 60〃 [dispersion liquid-B] 3,3'-dichlorophenylthiourea 10 parts N-stearylbenzamide 10〃 calcium carbonate 15 parts polyvinyl alcohol ( 10% aqueous solution) 30〃 water 40〃 [dispersion liquid-C] 3-diethylamino-7-chlorofluorane (red) 20
〃 10% hydroxyethyl cellulose aqueous solution 20〃 water 60〃 [dispersion liquid-D] 3,3-dichlorophenylthiourea 10 parts calcium carbonate 10〃 polyvinyl alcohol 10% aqueous solution 20〃 water 60〃 [dispersion liquid-E] crystal violet lactone ( Blue) 20 parts 10% Hydroxyethylcellulose aqueous solution 20〃 Water 60〃 [Dispersion-F] Bisphenol A 10 parts Calcium carbonate 10〃 10% Hydroxyethylcellulose aqueous solution 15〃 Water 65 parts Dispersion A prepared as above 10 parts , Dispersion B60 parts,
30 parts of water was taken, respectively, and mixed to obtain a thermosensitive color forming solution for low temperature. On the other hand, 10 parts of Dispersion C, 70 parts of Dispersion D, and 20 parts of water were respectively taken and mixed and stirred to obtain a thermosensitive color-forming layer-forming solution for medium-temperature color development.

Further, 10 parts of Dispersion E, 70 parts of Dispersion F and 20 parts of water were mixed and stirred to obtain a thermosensitive color forming layer forming liquid for high temperature color development. Further, a decolorant layer forming liquid for forming a decolorant layer was prepared in the following ratio.

[Decolorant layer forming liquid]

Decoloring agent in Table-1 20 parts 10% aqueous solution of polyvinyl alcohol 20〃 water 60〃 Next, the high temperature thermosensitive coloring layer forming liquid (dry coating amount) on a commercial high-quality paper having a basis weight of about 52g / m ^2. 5g / m ² ), decolorizing agent layer forming liquid (dry coating amount 3 g / m ² ), intermediate layer forming liquid terpene resin latex (solid content 40%) (dry coating amount 3 g / m ² ).
m ² ), medium temperature thermosensitive coloring layer forming liquid (dry coating amount 4.5 g /
m ² ), decolorizer layer forming liquid (dry coating amount 3 g / m ² ), terpene resin latex (solid content 4%) as intermediate layer forming liquid
(Coating amount when dry 3 g / m ² ) and low temperature thermosensitive color forming layer forming liquid (coating amount 4 g / m ² when drying) are applied and dried in order, then smooth
The multi-color recording materials of Examples 1 to 10 of the present invention were prepared by carrying out a calendering treatment for 00 seconds.

Comparative Example 1 In Example 1, the 1,3-bis (N-
N, N ′, N ″ − instead of benzoylpiperidyl) propane
A thermal recording material for comparison was prepared in the same manner as in Example 1 except that triphenylguanidine was used.

Comparative Example 2 In Example 1, 1,3-bis (N-
A thermal recording material for comparison was prepared in the same manner as in Example 1 except that N, N'-diphenyl-N "-cyclohexylguanidine was used in place of benzoylpiperidyl) propane.

The dynamic color forming characteristics of the multicolor thermosensitive recording materials of Examples and Comparative Examples obtained as described above were tested by a G-III facsimile test machine.

The test machine is 8 dots / mm from Matsushita Electronic Components Co., Ltd.
It has a thermal head, the resistance of the heating element is about 400 Ω / dot, and the color development test is a main scanning recording speed of 20 msec / line.
The sub scanning was 3.85 l / mm, the platen pressure was 3.0 kg / cm ² , and the head input was 0.6 W / dot. The coloring energy was 1.0 mJ for the low temperature coloring layer, 2.0 mJ for the medium temperature coloring layer and 3.3 mJ for the high temperature coloring layer.

A Macbeth densitometer was used for the concentration measurement.

As a result of the test, in Examples 1 to 5, the three constituent colors were clearly separated and developed, whereas in Comparative Examples 1 and 2, the three constituent colors exhibited a mixed color.

Claims (1)

[Claims] 1. A multicolor thermosensitive recording material having a structure in which a plurality of thermosensitive coloring layers that develop different tones are laminated and containing a decoloring agent, wherein a compound represented by the following general formula is used as the decoloring agent. A multicolor thermosensitive recording material characterized by. (In the formula, R represents an alkyl group, a cycloalkyl group, or an aryl group.)