JPH11170715A - Heat-sensitive multiple duplicating sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive multiple duplicating sheet of superior preservability with the lapse of the time of printing and light fastness. SOLUTION: A heat-sensitive multiple duplicating sheet is provided at least with an upper leaf heat-recording layer containing a leuco dye, a coloration agent and a bonding agent formed on one face of a first base sheet, a lower left recording sheet having a thermal transfer layer containing the leuco dye and a heat-soluble organic compound and a thermal transfer acceptive layer containing agent and the bonding agent and formed on one face of a second base sheet, and a zinc salt of a salicylic acid derivative and a benzotriazole base ultraviolet absorber are contained in the thermal transfer acceptive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material utilizing a color-forming reaction between a leuco dye and a color former, and more particularly to a heat-sensitive multi-copy sheet capable of simultaneously performing heat-sensitive recording on two or more sheets. is there.

[0002]

2. Description of the Related Art A thermosensitive recording medium is known which utilizes a color reaction between a leuco dye and a coloring agent to react both coloring materials with heat energy from a thermal head to obtain a recorded image. . Such a thermosensitive recording medium is relatively inexpensive, and its recording equipment is compact and easy to maintain, so that it is used not only as a recording medium for facsimile machines and various computers but also in a wide range of fields. In particular, after using thermal recordings as receipts,
There is an increasing demand for a thermosensitive recording medium capable of recording on a number of sheets with a single thermal recording.

As a means for recording a plurality of sheets by one thermal recording, it is conceivable to apply thermal recording in a state where a plurality of thermal recording media having a thermal recording layer formed on a support are stacked. However, clear thermal recording images cannot be formed on a plurality of sheets by the thermal head.

In order to obtain a clear thermosensitive recording image on a number of sheets, at least one surface of the first base sheet has a thermosensitive recording layer containing a leuco dye, a coloring agent and an adhesive. An upper leaf recording sheet having a thermal transfer layer containing a leuco dye and a heat-fusible organic compound on the other side of the sheet, and a thermal transfer receiving layer containing a colorant and an adhesive on one side of the second base sheet. A heat-sensitive multiplex copy sheet comprising a lower leaf recording sheet is described in JP-A-57-96895 and JP-A-57-96896.

However, in recent years, the range of applications of the heat-sensitive recording material has been widened, and particularly for credit card applications, the amount, date and time, details, etc. are recorded on a plurality of sheets at once by heat-sensitive recording, and pressure-sensitive recording by writing pressure with a ballpoint pen or the like. It is necessary that the customer's signature can be recorded on a plurality of sheets at once. There has been no satisfactory heat-sensitive multiple copy sheet that satisfies both the heat-sensitive recording property and the pressure-sensitive recording property at the same time. In addition, there is a problem in the storage stability over time and the light resistance of the printing on the lower leaf recording sheet.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a heat-sensitive multiplex copy sheet having excellent storage stability over time and light fastness.

[0007]

Means for Solving the Problems At least one surface of a first base material sheet has a heat-sensitive recording layer containing a leuco dye, a coloring agent and an adhesive, and the other surface of the sheet has a leuco dye and a heat-sensitive recording layer. A heat-sensitive sheet comprising an upper leaf recording sheet having a thermal transfer layer containing a fusible organic compound and a lower leaf recording sheet having a thermal transfer receiving layer containing a colorant and an adhesive on one surface of a second base sheet. In the multiple copy sheet, as one means for solving the above-mentioned problem, the present invention comprises a heat transfer receiving layer containing a zinc salt of a salicylic acid derivative and a benzotriazole-based ultraviolet absorber.

Further, by using a zinc salt of a salicylic acid derivative emulsified and dispersed in the thermal transfer receiving layer, it is possible to obtain an excellent effect on the recording sensitivity and pressure-sensitive recording characteristics of the lower paper. Among them, 2- (2'-hydroxy-5'-) was used as a benzotriazole-based ultraviolet absorber.
Methylphenyl) benzotriazole,
Excellent effects can be obtained due to the storage stability over time and the light fastness of the lower paper.

In particular, when a zinc salt of a salicylic acid derivative is emulsified and dispersed, a zinc salt of a salicylic acid derivative is used as a benzotriazole-based ultraviolet absorber in a liquid form of 2- (2 ′) at room temperature.
-Hydroxy-3′-dodecyl-5′-methylphenyl) benzotriazole emulsified and dispersed,
The lower sheet has excellent storage stability over time and light fastness, and also has an effect of excellent initial coloring during recording.

The heat-sensitive multiplex copy sheet of the present invention has a thermal transfer receiving layer on one surface of a third base sheet between the upper leaf recording sheet and the lower leaf recording sheet, and has a thermal transfer layer on the other surface. A middle leaf recording sheet may be provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that a zinc salt of a salicylic acid derivative and a benzotriazole type ultraviolet absorber are contained in a thermal transfer receiving layer. The amount used is not particularly limited, but is about 10 to 60% by weight, and preferably about 20 to 40% by weight, based on the thermal transfer receiving layer. The ratio of the zinc salt of the salicylic acid derivative to the benzotriazole-based ultraviolet absorber is preferably about 1: 3 to 3: 1 by weight.

Various known leuco dyes can be used as the leuco dye contained in the heat-sensitive recording layer and the thermal transfer layer formed on the first base sheet. Specific examples of the leuco dye include the following. Is exemplified. 3,3-bis (p
-Dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl) -6-dimethylaminophthalide, 3-diethylamino-7-di Blue-coloring dyes such as benzylamino-benzo [a] fluoran: 3- (N-ethyl-Np-tolyl) amino-7-
N-methylanilinofluoran, 3-diethylamino-
Green chromogenic dyes such as 7-anilinofluoran: 3-diethylamino-7-methylfluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-7-chlorofluoran, rhodamine (p -Chloroanilino) lactam, 3- (N-ethyl-p-toluidino) -7-methylfluoran, 3,3'-bis (1-n
Red-developing dyes such as -butyl-2-methylindol-3-yl) phthalide: 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran, 3
-(N-cyclohexyl-N-methyl) amino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N
-Ethoxypropylamino) -6-methyl-7-anilinofluoran, 3-dimethylamino-6-methyl-7-
Anilinofluoran, 3-di (n-butyl) amino-6
-Methyl-7-anilinofluoran, 3-di (n-butyl) amino-7- (o-chloroanilino) fluoran,
3-diethylamino-7- (o-fluoroanilino) fluoran, 3-diethylamino-7- (m-trifluoromethylanilino) fluoran, 3- (N-ethyl-p
-Toluidino) -6-methyl-7-anilinofluoran, 3- (N-ethyl-p-toluidino) -6-methyl-7- (p-toluidino) fluoran, 3-diethylamino-6-chloro-7- Black coloring dyes such as anilinofluoran, 3-di (n-amyl) amino-6-methyl-7-m-toluidinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, etc.

Specific examples of the colorant contained in the heat-sensitive recording layer include, for example, 4,4'-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4 -Hydroxyphenyl) -4
-Methylpentane, benzyl 4-hydroxybenzoate,
4,4′-dihydroxydiphenyl sulfone, 2,4 ′
-Dihydroxydiphenylsulfone, 4-hydroxy-
4'-isopropyloxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4
-Hydroxy-4'-methyldiphenylsulfone, 4-
Hydroxyphenyl-4′-benzyloxyphenylsulfone, 1,1-bis (4-hydroxyphenyl) -1
-Phenylethane, 1,4-bis [α-methyl-α-
(4'-hydroxyphenyl) ethyl] benzene, 1,
Phenolic compounds such as 3-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene;
4'-bis (p-tolylsulfonylaminocarbonylamino) diphenylmethane, Np-tolylsulfonyl-
Sulfourea compounds such as N'-phenylurea, zinc p-chlorobenzoate, zinc 4- [2- (p-methoxyphenoxy) ethyloxy] salicylate, 4- [3- (p-
Tolylsulfonyl) propyloxy] zinc salicylate,
Zinc salts of aromatic carboxylic acids such as 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] zinc salicylate.

Of course, the leuco dye and the color former are not limited to these, and two or more of them can be used in combination as needed. As the amount of leuco dye used,
The heat-sensitive recording layer accounts for about 3 to 35% by weight of the heat-sensitive recording layer, and the thermal transfer layer uses about 3 to 50% by weight of the heat-transfer layer. The amount of the coloring agent used in the heat-sensitive recording layer is about 10 to 70% by weight based on the heat-sensitive recording layer.

The heat-sensitive recording layer is formed, for example, by using water as a dispersion medium,
The leuco dye and the color former are separately or together finely dispersed by a pulverizer such as a ball mill, an attritor, a sand mill or the like so that the average particle diameter becomes about 0.1 to 3 μm. The coating liquid for the heat-sensitive recording layer prepared by adding the agent while mixing and stirring with a stirrer is applied to one surface of the first substrate sheet and dried so that the coated amount after drying is about 2 to 7 g. Is done.

Specific examples of the adhesive contained in the heat-sensitive recording layer coating solution include styrene-butadiene latex, vinyl acetate-vinyl chloride-ethylene copolymer latex, methyl methacrylate-butadiene copolymer latex, and the like. Water-dispersible resin, and starch, oxidized starch, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, completely (partially) saponified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, carboxy-modified polyvinyl Water solubility of alcohol, diisobutylene-maleic anhydride copolymer salt, styrene-maleic anhydride copolymer salt, ethylene-acrylic acid copolymer salt, styrene-acrylic acid copolymer salt, etc. Butter, and the like. The amount of the adhesive used is 5 to 40 with respect to the total solid content of the heat-sensitive recording layer.
% By weight.

Further, in the coating solution for the heat-sensitive recording layer, if necessary, for example, m-terphenyl, dibenzyl oxalate, di-p-chlorobenzyl oxalate, di-p-methylbenzyl oxalate, 1,2 -Sensitizers such as diphenoxyethane, 1,2-di (3-methylphenoxy) ethane and 2-naphthylbenzyl ether; 4-benzyloxy-4'-
(2-methyl-2,3-epoxypropyloxy) diphenyl sulfone, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy- 5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4
-Hydroxy-5-tert-butylphenyl) butane and the like, sodium dioctyl sulfosuccinate, sodium dodecylbenzene sulfonate, sodium polystyrene sulfonate, sodium lauryl alcohol sulfate, sodium alginate, fatty acid metal salt Surfactants such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, amorphous silica, aluminum hydroxide, barium sulfate, talc, kaolin, clay,
Calcined clay, nylon filler, pigments such as urea formalin resin filler, and defoamer, fluorescent dye, colored dye,
An auxiliary agent such as a crosslinking agent can be added.

The heat-fusible organic compound contained in the thermal transfer layer is not particularly limited as long as it is an organic compound having a melting point of about 35 to 150 ° C., for example, carnauba wax, montan wax, paraffin wax, microcrystalline wax, Polyethylene wax, palmitic acid, stearic acid, behenic acid, stearic acid amide, ethylenebisstearic acid amide, methyl stearate,
Higher aliphatic compounds such as stearic acid anilide are preferred because of their excellent pressure-sensitive recording properties. The amount of the heat-fusible organic compound used is about 30 to 90% by weight, preferably about 40 to 80% by weight, based on the total solids of the thermal transfer layer.

Specific examples of the zinc salt of a salicylic acid derivative contained as a colorant in the thermal transfer receiving layer formed on one surface of the second substrate sheet include, for example, a zinc salt of a salicylic acid derivative. Are zinc 3-isopropylsalicylate, 3-tert-butylsalicylic acid, zinc 3-benzylsalicylate 3- (α-methylbenzyl) salicylate, zinc 3-chloro-5- (αmethylbenzyl) salicylate, 3,5-di -Zinc tert-butylsalicylate, 3,
Zinc 5-di (α-methylbenzyl) salicylate, zinc 3-phenyl-5- (α, α-dimethylbenzyl) salicylate, zinc 3,5-di-tert-octylsalicylate,
Zinc 3,5-di-tert-nonylsalicylate, zinc 3,5-di-tert-dodecylsalicylate, zinc 5-tert-dodecylsalicylate, zinc 5-cyclohexylsalicylate,
4- [2- (p-methoxyphenoxy) ethyloxy]
Zinc salicylate, 4- [3- (p-tolylsulfonyl)
Propyloxy] zinc salicylate, 5- [p- (2-p
-Methoxyphenoxyethoxy) cumyl] zinc salicylate, mono [poly (0-4) [ω-hydro [poly (1
7) α-methylbenz] -α-yl] benzyl] zinc salicylate, mono (or bis or tri or tetrakis)
Zinc salts of [poly (0-4) [ω-hydro [poly (1-7) α-methylbenz] -α-yl] benzyl] salicylic acid-styrene copolymer. Above all, mono (or bis or tri or tetrakis) [poly (0-4)
[Ω-hydro [poly (1-7) α-methylbenz] -α
A zinc salt of [-yl] benzyl] salicylic acid-styrene copolymer is preferable because of its excellent recording density.

In addition to the zinc salt of the salicylic acid derivative, it is also possible to use a coloring agent contained in the above-mentioned heat-sensitive recording layer and a clay such as acid clay, activated clay, attapulgite, zeolite and bentonite as a coloring agent.

Specific examples of the benzotriazole-based ultraviolet absorber contained in the thermal transfer receiving layer include, for example, 2-
(2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-dodecyl-5,- Methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-undecyl-5′-methylphenyl) benzotriazole,
2- [2'-hydroxy-4 '-(1 "-propylhexyl) oxyphenyl] benzotriazole, polyethylene glycol (molecular weight about 300) and methyl-3-
(2H-benzotriazol-2-yl) -5-tert-
And benzotriazole-based UV absorbers such as condensates with [butyl-4-hydroxyphenyl] propionate. Of course, the present invention is not limited to these, and two or more of them can be used as needed. Furthermore,
Various dimer and trimer benzotriazole ultraviolet absorbers are also included. Further, the benzotriazole-based ultraviolet absorber can be used by being encapsulated in microcapsules having an average particle diameter of 3 μm or less.

The thermal transfer receiving layer is obtained by mixing and stirring a zinc salt of a salicylic acid derivative finely dispersed to have an average particle diameter of about 0.1 to 3 μm with water and an adhesive using water as a dispersion medium. The liquid is formed by applying and drying the liquid on one surface of the second base material sheet so that the applied amount after drying is about 1 to 7 g / m ² . In particular, a zinc salt of a salicylic acid derivative, which is dissolved in an organic solvent such as toluene, xylene, or diisopropylnaphthalene and then emulsified and dispersed, is excellent in recording sensitivity, and thus is preferable.

As the adhesive contained in the coating solution for the thermal transfer receiving layer, those contained in the heat-sensitive recording layer are used. Further, an auxiliary agent contained in the heat-sensitive recording layer may be added to the coating solution for the heat transfer receiving layer.

Examples of the method of applying the coating solution for the heat-sensitive recording layer and the coating solution for the thermal transfer receiving layer include an air-knife system, a Meyer bar system, a pure blade system, a rod blade system, a reverse roll system, a gravure system, and a slit die system. And the like.

The thermal transfer layer is generally coated with a coating liquid for a thermal transfer layer in which a leuco dye is added to a heat-fusible, heat-fusible organic compound on the other surface of the first base sheet at about 1 to 8 g / m ^2. For example, it is formed by applying by a hot melt method.

The first and second base sheets include, for example, high quality papers, films, and synthetic papers of about ²⁰ to 80 g / m ² . In particular, in the first base sheet, 2
Glassine paper of about 0 to 40 g / m ² is preferred.

[0027]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but it is needless to say that the present invention is not limited thereto. Unless otherwise specified, parts and% in the examples are parts by weight and% by weight, respectively.

Example 1 [Preparation of Solution A] 10 parts of 3-di (n-butyl) amino-6-methyl-7-anilinofluoran, sulfone-modified polyvinyl alcohol (trade name: Goselan L-3266, Nippon Synthetic Chemistry) 5 parts of a 10% aqueous solution and water 25
Part of the composition having a mean particle size of 0.
The solution A was obtained by pulverizing until the thickness became 8 μm.

[Preparation of Solution B] 10 parts of 4-hydroxy-4'-isopropoxydiphenylsulfone, sulfone-modified polyvinyl alcohol (trade name: Goselan L-326)
6, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and pulverized with a sand mill until the average particle size became 1.5 μm.

[Preparation of Solution C] A composition comprising 10 parts of m-terphenyl, 5 parts of a 10% aqueous solution of sulfone-modified polyvinyl alcohol (trade name: Gohcelan L-3266, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and 25 parts of water. Was pulverized with a sand mill until the average particle diameter became 1.0 μm to obtain a liquid C.

[Preparation of Coating Solution for Thermosensitive Recording Layer] 40 parts by weight of Liquid A, 80 parts by weight of Liquid B, 40 parts by weight of Liquid C, amorphous silica (trade name: Mizuka Seal P-527, manufactured by Mizusawa Chemical) 15
Parts by weight, completely saponified polyvinyl alcohol (trade name: P
VA-105, manufactured by Kuraray Co., Ltd.)
2 parts of a 20% aqueous solution of glyoxal and 30 parts of water were mixed and stirred to obtain a coating solution for a heat-sensitive recording layer.

[Preparation of Coating Solution for Thermal Transfer Layer] 10 parts of 3-piperidino-6-methyl-7-anilinofluoran, 30 parts of carbana wax and 15 parts of stearamide were mixed with 1 part.
It was melted at 20 to 130 ° C. to obtain a coating liquid for a thermal transfer layer.

[Preparation of Coating Solution for Thermal Transfer Receiving Layer] 65 parts of aluminum hydroxide, 20 parts of zinc oxide, mono (or bis, tri or tetrakis) [poly (0-4) [ω-hydro [poly (1-7 ) Α-methylbenz] -α-yl] benzyl] salicylic acid-styrene copolymer zinc salt (weight ratio of zinc salt of salicylic acid to styrene in the copolymer is 1: 1; average particle diameter 2.1 μm) 50 parts of a 30% aqueous dispersion, 30 parts of a 30% aqueous dispersion of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole (average particle size 1.8 μm), and 10% of a carboxy-modified polyvinyl alcohol 50 parts by weight of an aqueous solution, 10 parts of a 20% aqueous solution of a polyamide epichlorohydrin resin as a waterproofing agent, 40 parts by weight of a styrene-butadiene resin having a glass transition point of 2 ° C. (solid concentration: 50%), By stirring and mixing a composition consisting of 20% aqueous solution of 5 parts and 100 parts of water of sodium acrylate to obtain a thermal transfer receiving layer coating solution.

[Preparation of upper leaf recording sheet] Basis weight 35 g / m
^2. On one surface (front surface side) of a 35 μm-thick glassine paper (first base sheet), the coating liquid for thermal recording was applied and dried so that the coating amount after drying was 4.0 g / m ² . After that, a super calender treatment was performed to provide a heat-sensitive recording layer, and a coating solution for a heat transfer layer having a temperature of 70 to 80 ° C. was applied to the other surface (rear side) at a rate of 3.2 g / m ^2. An upper leaf recording sheet was formed.

[Preparation of middle sheet recording sheet] Basis weight 35 g / m
^2. On one surface (front surface side) of 35 μm thick glassine paper (third substrate sheet), apply and dry the coating solution for the thermal transfer receiving layer so that the coating amount after drying is 5.4 g / m ^2. Then, a super calender treatment is performed to provide a thermal transfer receiving layer, and the other surface (back side) is coated with 3.2 g / m ² of a thermal transfer layer coating solution at a temperature of 70 to 80 ° C., and then cooled to form a thermal transfer layer. Was formed to obtain a midleaf recording sheet.

[Preparation of lower leaf recording sheet] Basis weight 64 g / m
^2. The coating amount after drying the coating solution for the thermal transfer receiving layer on one side (front side) of the neutral high-quality paper (second base sheet) is 5.
A thermal transfer receiving layer was formed by coating and drying at 4 g / m ^2, and then subjected to a super calender treatment to obtain a lower leaf recording sheet.

[Preparation of Thermally Multiplexed Copy Sheet] The back side of the upper leaf recording sheet and the front side of the middle leaf recording sheet, and the back side of the middle leaf recording sheet and the front side of the lower leaf recording sheet cut into A4 size are in contact with each other. To form a thermosensitive multiple copy sheet.

Example 2 In the preparation of the coating solution for the thermal transfer receiving layer in Example 1,
2- (2'-hydroxy-3'-dodecyl-5'-methylphenyl) benzotriazole instead of 30 parts of a 30% aqueous dispersion of (2'-hydroxy-5'-methylphenyl) benzotriazole [Product name: Tinuvin 1
(Manufactured by Ciba Geigy Co., Ltd.) in an amount of 80% by weight with respect to the microcapsules, having a wall film made of a polyurethane polyurea resin (average particle diameter 1.8 μm)
Example 1 except that 30 parts of a 30% dispersion of m) were used.
In the same manner as in the above, a heat-sensitive multiple copy sheet was obtained.

Example 3 In the preparation of the coating solution for the thermal transfer receiving layer in Example 1, mono (or bis or tri or tetrakis) [poly (0-4)
[Ω-hydro [poly (1-7) α-methylbenz] -α
Instead of 50 parts of a 30% dispersion of a zinc salt of -yl] benzyl] salicylic acid-styrene copolymer, toluene 2 was added to 40 parts of a 5% aqueous solution of sulfone-modified polyvinyl alcohol.
0 parts, diisopropyl naphthalene 1 part and mono (or bis or tri or tetrakis) [poly (0-4) [ω-
Emulsifying and dispersing a composition comprising 8 parts of zinc hydro [poly (1-7) α-methylbenz] -α-yl] benzyl] salicylate (average emulsified particle diameter of 1.8 μm) and then degassing toluene A heat-sensitive multiple copy sheet was obtained in the same manner as in Example 1 except that 50 parts were used.

Example 4 In the preparation of the coating solution for the thermal transfer receiving layer in Example 1, a mono (or bis or tri or tetrakis) [poly (0-4)
[Ω-hydro [poly (1-7) α-methylbenz] -α
-Yl] benzyl] salicylic acid-styrene copolymer zinc salt 30% dispersion 50 parts, instead of zinc 3,5-di (α-methylbenzyl) salicylate and α-methylstyrene.
Melt with styrene copolymer (melt weight ratio = 80/2)
0, and an average particle diameter of 2.3 μm), except that a dispersion was used in the same manner as in Example 1 to obtain a thermosensitive multiplex copying sheet.

Example 5 In the preparation of the coating solution for the thermal transfer receiving layer of Example 1, a mono (or bis, tri or tetrakis) [poly (0-4)
[Ω-hydro [poly (1-7) α-methylbenz] -α
50 parts of a 30% dispersion of zinc salt of -yl] benzyl] salicylic acid-styrene copolymer and 30% of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole (average particle diameter 1.8 μm) Instead of 30 parts of the aqueous dispersion, a 5% aqueous solution of sulfone-modified polyvinyl alcohol 60
Part, toluene 20 parts, 3,5-di-α-methylbenzylsalicylic acid zinc salt 8 parts, 2- (2′-hydroxy-3 ′)
-Dodecyl-5'-methylphenyl) benzotriazo-
The composition comprising 9 parts of emulsion was emulsified and dispersed (average emulsified particle size of 2.
1 μm), and a heat-sensitive multiple copy sheet was obtained in the same manner as in Example 1 except that 80 parts of a dispersion obtained by degassing toluene was used.

Comparative Example 1 In the preparation of the coating solution for the thermal transfer receiving layer in Example 1,
A heat-sensitive multiple copy sheet was obtained in the same manner as in Example 1 except that 30 parts of a 30% aqueous dispersion of (2'-hydroxy-5'-methylphenyl) benzotriazole was not added.

Comparative Example 2 In the preparation of the coating solution for the thermal transfer receiving layer of Example 1, mono (or bis, tri or tetrakis) [poly (0-4)
[Ω-hydro [poly (1-7) α-methylbenz] -α
Bis- (3-allyl-benzyl) salicylic acid-styrene copolymer zinc salt instead of 50 parts of a 30% dispersion.
4-hydroxyphenyl) sulfone (average particle size 2.1)
Example 1 except that 50 parts of a 30% dispersion were used.
In the same manner as in the above, a heat-sensitive multiple copy sheet was obtained.

Comparative Example 3 In the preparation of the coating solution for the thermal transfer receiving layer of Example 1, a mono (or bis or tri or tetrakis) [poly (0-4)
[Ω-hydro [poly (1-7) α-methylbenz] -α
-Yl] benzyl] salicylic acid-styrene copolymer zinc salt, instead of 50 parts of a 30% dispersion, 30 parts of 4,4'-isopropylidene diphenol (average particle diameter 2.5 μm)
A thermosensitive multiple copy sheet was obtained in the same manner as in Example 1 except that 50 parts of the% dispersion was used.

Comparative Example 4 In the preparation of the coating solution for the thermal transfer receiving layer of Example 1,
Example 1 except that a 30% aqueous dispersion of 2,4-dihydroxybenzophenone was used instead of the 30 parts aqueous dispersion of (2'-hydroxy-5'-methylphenyl) benzotriazole. In the same manner as in the above, a heat-sensitive multiple copy sheet was obtained.

The following evaluation test was carried out on the thus obtained heat-sensitive multiplex copy sheet, and the obtained results are shown in Table 1.

An applied energy of 0.45 mJ / do was measured by using a thermal evaluation device (trade name: TH-PMD, manufactured by Okura Electric Co., Ltd.).
At t, each heat-sensitive multiplexed copy sheet was recorded, and the density of the recorded portion after 1 minute and 10 minutes recorded on the thermal transfer receiving layer of the middle leaf recording sheet was measured with a Macbeth densitometer (RD-914, manufactured by Macbeth). Measured in visual mode.

[Heat Resistance Storage Property] The above-mentioned middle-leaf recording sheet recorded by the heat-sensitive evaluator was stored at a temperature of 60 ° C. for 24 hours, and the recording density after storage was measured by a Macbeth densitometer [RD-91].
Type 4, manufactured by Macbeth Co.] in the visual mode.

[Moisture resistance storage property] The above-mentioned middle leaf recording sheet recorded by the heat-sensitive evaluator was stored for 24 hours under the conditions of a temperature of 40 ° C and a humidity of 90% RH, and the recording density after storage was measured using a Macbeth densitometer [RD- Model 914, manufactured by Macbeth Co.] in the visual mode.

[Light Storage Preservation] The recording density after irradiating the above-mentioned middle sheet recording sheet recorded by the above-described heat-sensitive evaluation machine with a xenon fade meter (suga test machine) for 15 hours (xenon arc) was measured using a Macbeth densitometer [RD-914]. , Macbeth Co., Ltd.] in the visual mode, and the results are shown in Table 1.

[0051]

[Table 1]

[0052]

As shown in Table 1, the multiple thermographic copying sheet of the present invention has an effect particularly excellent in storage stability of printing over time and light resistance.

Claims (3)

[Claims] 1. A heat-sensitive recording layer containing a leuco dye, a coloring agent and an adhesive on at least one surface of a first base sheet, and a leuco dye and a heat-fusible organic material on the other surface of the sheet. A thermal multiple copy sheet comprising an upper leaf recording sheet having a thermal transfer layer containing a compound and a lower leaf recording sheet having a thermal transfer receiving layer containing a colorant and an adhesive on one surface of a second base sheet. A heat-sensitive multicopy sheet comprising a heat transfer receiving layer containing a zinc salt of a salicylic acid derivative and a benzotriazole-based ultraviolet absorber. 2. The heat-sensitive multiple copy sheet according to claim 1, wherein the zinc salt of a salicylic acid derivative in the thermal transfer receiving layer is obtained by emulsification and dispersion. 3. The benzotriazole type ultraviolet absorber in the thermal transfer receiving layer is 2- (2′-hydroxy-5′-methylphenyl) benzotriazole or 2- (2′-hydroxy-3′-dodecyl-5 ′). 3. The heat-sensitive multi-copy sheet according to claim 1, which is (-methylphenyl) benzotriazole.