JPH06297846A - Heat-sensitive recording body - Google Patents

Abstract

PURPOSE:To provide a heat-sensitive recording body wherein a hue of a recording image is different from a hue to be obtained by reaction between colorless or light-colored basic dye and a coloration agent. CONSTITUTION:In a heat-sensitive recording body, a heat-sensitive recording layer containing colorless or light-colored basic dye and a coloration agent is provided on a substrate and a layer containing an inorganic pearl pigment is provided on a heat-sensitive recording 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, and more particularly to a heat-sensitive recording material in which a hue of a recorded image is different from a hue due to a reaction between a colorless or light basic dye and a coloring agent.

[0002]

2. Description of the Related Art A heat-sensitive recording material which utilizes a color reaction between a colorless or light-colored basic dye and an organic or inorganic color-forming agent to bring both color-forming substances into contact with each other by heat to obtain a recorded image is often used. Are known. Since such a thermosensitive recording medium is relatively inexpensive, the recording device is compact, and its maintenance is easy, it is used not only as a recording medium for facsimiles and various computers but also in a wide range of fields.

The hue of the recorded image of a thermosensitive recording medium utilizing the reaction of such a colorless or pale basic dye (leuco dye) and a coloring agent is the same as the used leuco dye and coloring agent when the background is white. Only the hue by the reaction of is obtained.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermosensitive recording medium in which the hue of a recorded image is different from the hue due to the reaction between a colorless or light basic dye and a color former.

[0005]

Means for Solving the Problems As a result of intensive studies aimed at achieving this object, the present inventors have provided a heat-sensitive recording layer containing a colorless or light basic dye and a color former on a support. In the heat-sensitive recording material, by providing a layer containing an inorganic pearl pigment on the heat-sensitive recording layer, it is possible to obtain a heat-sensitive recording material in which the hue of the recorded image is different from the hue due to the reaction between the leuco dye and the color former. I found it.

Further, as a result of extensive research, the inventors of the present invention found that the presence of a heat-fusible substance in the layer containing the inorganic pearl pigment makes it possible to obtain a recorded image having a more vivid hue. It came to completion.

[0007]

As described above, the present invention uses the inorganic pearl pigment to change the hue of a recorded image. The inorganic pearl pigment used in the present invention is a pearl pigment obtained by coating the surface of bismuth oxychloride, natural or synthetic mica with a metal oxide having a high refractive index such as titanium oxide, iron oxide or tin oxide. The coverage of the metal oxide on the mica is not particularly limited, but is preferably about 5 to 90%, and more preferably 10 to 70%.
The particle size of the pearl pigment is 1 to 500 μm, preferably 3 to 250 μm.

The layer containing a pearl pigment is heat-sensitive by printing, for example, by finishing an inorganic pearl pigment into an organic solvent-based paint or an aqueous paint, and applying it to a printing ink such as a screen ink, a gravure ink or an offset ink. It is provided on the recording layer or on the protective layer provided on the thermosensitive recording layer. The addition rate of the specific inorganic pearl pigment in the coating liquid or ink is appropriately selected depending on the method of use, but is 0.01 to 90% by weight, preferably 0.1.
It is desirable to adjust in the range of -60% by weight.

Further, according to the present invention, a clear recorded image can be obtained by incorporating a heat-fusible substance in the specific pigment layer. The heat-fusible substance has a melting point of 40 to 15 which is solid at room temperature and melts when heated by a thermal head.
A substance at 0 ° C. is preferable, and specifically, for example, polyethylene wax, paraffin wax, ester wax,
Carnauba wax, caproic acid amide, capric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, linolenic acid amide, N-methylstearic acid amide, stearic acid anilide, N-methyloleic acid Amide, benzanilide, linoleic acid anilide, N-ethylcapric acid amide, N-butyllauric acid amide, N-octadecylacetamide, N-oleinacetamide, N-oleylbenzamide, N-stearylcyclohexylamide, polyethylene glycol, 1-benzyloxy Naphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, 1,2-diphenoxyethane, 1,4-diphenoxybutane, 1,2-bis (3-methylpheno) ) Ethane, 1,2-bis (4-
Methoxyphenoxy) ethane, 1-phenoxy-2-
(4-chlorophenoxy) ethane, 1-phenoxy-2
-(4-Methoxyphenoxy) ethane, terephthalic acid dibenzyl ester, oxalic acid dibenzyl ester, oxalic acid di (4-methylbenzyl) ester, p-benzyloxybenzoic acid benzyl ester, p-benzylbiphenyl, 1,5- Bis (p-methoxyphenoxy) -3-
Oxapentane, 1,4-bis (2-vinyloxyethoxy) benzene, p-biphenyl-p-tolyl ether, benzyl-p-methylthiophenyl ether, 2-
Examples of the compound include (2'-hydroxy-5'-methylphenyl) benzotriazole and 2-hydroxy-4-benzyloxybenzophenone. Of course, it is possible to use two or more kinds of these heat-fusible substances together if necessary. Above all, paraffin wax from which the low melting point is cut is preferable because the contour of the recorded image becomes clearer. Further, the heat-fusible substance may be finely divided by a pulverizer such as a sand mill or may be emulsified, but an emulsifying type capable of obtaining a uniform particle size is preferable because it causes less bleeding of a recorded image.

When these heat-fusible substances are used in combination, it is preferable to use 1 to 300 parts by weight, preferably 5 to 150 parts by weight, based on 100 parts by weight of the pearl pigment. Incidentally, when the amount is less than 1 part by weight, the desired effect is hardly obtained. On the other hand, if the amount exceeds 300 parts by weight, the hue of the recorded image tends to be unclear.

In the present invention, the paint for forming the pearl pigment or the layer containing the pearl pigment and the heat-fusible substance is, for example, a pearl pigment and the heat-fusible substance dispersed in an acrylic clear lacquer or the like, and It is prepared by dispersing it in a solvent-based ink medium, or by dispersing it in water together with a water-soluble resin or the like. Examples of the water-soluble resin used in such an aqueous dispersion coating liquid include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol. Examples include silicon-modified polyvinyl alcohol, sulfone-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol, and graft copolymers of polyvinyl alcohol and (acrylamide / acrylic acid derivative / acrylonitrile) copolymers. it can.

Further, in the paint, if necessary, a surfactant such as sodium dioctylsulfosuccinate (dispersant,
Wetting agents), ultraviolet absorbers, defoamers, fluorescent dyes, coloring dyes, and various auxiliaries such as water-soluble polyvalent metal salts such as potassium alum and aluminum acetate may be appropriately added. Further, in order to further improve the water resistance, a curing agent such as glyoxal, boric acid, dialdehyde starch, and an epoxy compound can be used in combination. In addition, a metallic hue can be obtained by using an appropriate amount of carbon black or the like.

A coating material containing a specific pigment is gently and sufficiently mixed and dispersed by a mixing / stirring machine such as a mixer, an attritor, a ball mill or a roll mill, if necessary, and then heat-sensitive recorded by various known coating devices or printing devices. It is applied and dried on the layer or on the protective layer provided on the heat-sensitive recording layer. After application, it can be dried by irradiation with ultraviolet rays or electron beams. The coating amount of the coating material is not particularly limited, but if the coating amount after drying is less than 0.1 g / m ² , the desired effect of the present invention cannot be obtained, and if it exceeds 20 g / m ^2. Since the recording sensitivity of the thermosensitive recording medium may be significantly lowered, it is 0.1 to 20 g / m ² , preferably 0.5 to 10 g / m ² .
It is desirable to prepare it in the range of about g / m ² . It should be noted that two or more layers having a pearl pigment may be stacked.

Various types of basic dyes, which are colorless or light-colored, to be used in the heat-sensitive recording layer of the present invention are known, and examples thereof include the following. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3
-Bis (p-dimethylaminophenyl) phthalide, 3-
(P-Dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) fritado, 3- (p-dimethylaminophenyl) -3- (2-methylindole-
3-yl) fritado, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3-)
Yl) -6-Dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -6-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -6 -Dimethylaminophthalide, 3-p
-Triarylmethane dyes such as dimethylaminophenyl-3- (1-methylpyrrol-3-yl) -6-dimethylaminophthalide, 4,4'-bis-dimethylaminobenzhydrylbenzyl ether, N-halophenyl −
Diphenylmethane dyes such as leuco auramine and N-2,4,5-trichlorophenyl leuco auramine, thiazine dyes such as benzoyl leuco methylene blue and p-nitrobenzoyl leuco methylene blue, 3-methyl-
Spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3-phenyl-spiro-dinaphthopyran, 3
-Spiro dyes such as benzyl-spiro-dinaphthopyran, 3-methyl-naphtho- (6'-methoxybenzo) spiropyran, 3-propyl-spiro-dibenzopyran, rhodamine-B anilinolactam, rhodamine (p-nitroanilino) lactam , Lactam dyes such as rhodamine (o-chloroanilino) lactam, 3-dimethylamino-7-methoxyfluorane, 3-diethylamino-6-
Methoxyfluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-6,7-dimethylfluorane, 3- (N-ethyl-p-toluidino) -7-methylfluorane, 3-diethylamino-7- (N-acetyl-N-methylamino) fluorane, 3-diethylamino-7-N-methylaminofluorane, 3 -Diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7- (N-methyl-N-benzylamino) fluorane, 3-diethylamino-7- (N-chloroethyl-N-methylamino) fluorane, 3-diethylamino -7-Diethylaminofluorane, 3- (N-ethyl-p-toluidino 6-methyl-7-phenylamino fluoran, 3- (N-cyclopentyl--N- ethylamino) -6-methyl-7-anilinofluoran, 3-
(N-ethyl-p-toluidino) -6-methyl-7-
(P-Toluidino) fluorane, 3-diethylamino-
6-methyl-7-phenylaminofluorane, 3-di (n-butyl) amino-6-methyl-7-phenylaminofluorane, 3-di (n-pentyl) amino-6-methyl-7-phenylamino Fluorane, 3-diethylamino-7- (2-carbomethoxy-phenylamino) fluorane, 3- (N-ethyl-N-isoamylamino)
-6-Methyl-7-phenylaminofluorane, 3-
(N-cyclohexyl-N-methylamino) -6-methyl-7-phenylaminofluorane, 3-pyrrolidino-
6-methyl-7-phenylaminofluorane, 3-piperidino-6-methyl-7-phenylaminofluorane,
3-diethylamino-6-methyl-7-xylidinofluorane, 3-diethylamino-7- (o-chlorophenylamino) fluorane, 3-dibutylamino-7- (o
-Chlorophenylamino) fluorane, 3-pyrrolidino-6-methyl-7-p-butylphenylaminofluorane, 3- (N-methyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 3-
(N-ethyl-N-tetrahydrofurfurylamino)-
Fluoran dyes such as 6-methyl-7-anilinofluorane.

Various compounds are known as colorants used in combination with basic dyes, and the following are exemplified. Inorganic acid substances such as activated clay, acid clay, attapulgite, bentonite, aluminum silicate, 4-hydroxydiphenoxide, α-naphthol, β-naphthol, 4-hydroxyacetophenone, 4-tert-butylphenol, hydroquinone, 4-tert-octyl Catechol, 4,4'-isopropylidenediphenol,
4,4'-cyclohexylidene diphenol, 2,2 '
-Dihydroxydiphenol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,
4'-isopropylidene bis (2-tert-butylphenol), 4,4'-sec-butylidene diphenol, 4
-Phenylphenol, 2,2'-methylenebis (4-
(Chlorophenol), 4,4'-dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxy-4'-chlorodiphenyl sulfone, 4-hydroxy-4 '. -Methoxydiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, benzyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, hydroquinone monobenzyl ether, novolac type phenol resin, phenolic compounds such as phenol polymer, Benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3
-Sec-Butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid, 3-tert-butylsalicylic acid, 3-benzyl Salicylic acid, 3- (α-methylbenzyl) salicylic acid, 3-chloro-5- (α-methylbenzyl) salicylic acid, 3,5-di-tert-butylsalicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) ) Salicylic acid,
Aromatic carboxylic acids such as 3,5-di-α-methylbenzyl salicylic acid, and these phenolic compounds, aromatic carboxylic acids and polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel Organic acid substances such as salt.

In the present invention, the use ratio of the colorless or light-colored basic dye and the coloring agent in the heat-sensitive recording layer should be appropriately selected according to the types of the basic dye and the coloring agent used, and is not particularly limited. However, in general, 1 to 7 parts by weight, preferably 1 to 4 parts by weight, of a coloring agent is used per 1 part by weight of the basic dye. The coating liquid containing these substances is generally prepared by using water as a dispersion medium, stirring with a ball mill, an attritor, a sand mill or the like, and dispersing the color former and the color former together or separately by a pulverizer. The liquid is prepared to have an average particle size of 1 μm or less, preferably 0.5 μm or less.

In such coating liquid, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride are usually used as binders. Copolymer salt, ethylene / acrylic acid copolymer salt,
Styrene / acrylic acid copolymer salt, natural rubber emulsion, styrene / butadiene copolymer emulsion, acrylonitrile / butadiene copolymer emulsion, methyl methacrylate / butadiene copolymer emulsion, polychloroprene emulsion, vinyl acetate emulsion, ethylene At least one kind such as vinyl acetate emulsion is added in an amount of 10 to 40% by weight, preferably 15 to 35% by weight, based on the total solid content of the recording layer.

If necessary, various auxiliary agents can be added to the coating liquid. For example, sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate, dispersant such as fatty acid metal salt, stearin. Waxes such as zincate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, defoaming agent,
Fluorescent dyes, coloring dyes, etc. are appropriately added.

Further, various pigments can be used in combination in the coating liquid as long as the characteristics of the present invention are not impaired. For example, the above-mentioned pearl pigment, kaolin, clay, calcium carbonate,
Inorganic pigments such as calcined clay, calcined kaolin, diatomaceous earth, particulate anhydrous silica, activated clay and styrene microballs,
Examples include organic pigments such as nylon powder, polyethylene powder, urea / formalin resin filler, and raw starch particles.

Further, a sensitizer may be used in combination depending on the purpose. Specific examples of the sensitizer include, for example, stearic acid amide, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebistearic acid amide, behenic acid amide, and methylenebisstearic acid. Amide, N-
Methylol stearamide, dibenzyl terephthalate, dimethyl terephthalate, dioctyl terephthalate,
Benzyl p-benzyloxybenzoate, phenyl 1-hydroxy-2-naphthoate, 2-naphthylbenzyl ether, m-terphenyl, dibenzyl oxalate, oxalate-di-p-methylbenzyl, oxalate-di-p- Chlorobenzyl, p-benzylbiphenyl, tolylbiphenyl ether, di (p-methoxyphenoxyethyl) ether, 1,2-di (3-methylphenoxy) ethane,
1,2-di (4-methylphenoxy) ethane, 1,2-
Di (4-methoxyphenoxy) ethane, 1,2-di (4
-Chlorophenoxy) ethane, 1,2-diphenoxyethane, 1- (4-methoxyphenoxy) -2- (2-methylphenoxy) ethane, p-methylthiophenylbenzyl ether, 1,4-di (phenylthio) butane, p
-Acetotoluidide, p-acetophenetidide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane and the like are exemplified. To be done. The amount of these sensitizers used is not particularly limited, but it is generally desirable to adjust the amount within the range of 4 parts by weight or less relative to 1 part by weight of the color developing agent.

In the present invention, a storability improver may be used in combination so as to further enhance the storability of a recorded image according to the purpose unless the effect is impaired. Specific examples of such storage improvers include 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-ethylenebis (4-methyl-6-tert-butylphenol) 2.
2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4,6-di-te)
rt-butylphenol), 2,2'-ethylidenebis (4,6-di-tert-butylphenol), 2,2'-
Ethylidene bis (4-methyl-6-tert-butylphenol), 2,2'-ethylidene bis (4-ethyl-6-)
tert-butylphenol), 2,2 '-(2,2-propylidene) bis (4,6-di-tert-butylphenol), 2,2'-methylenebis (4-methoxy-6-te)
rt-butylphenol), 2,2'-methylenebis (6
-Tert-butylphenol), 4,4'-thiobis (3
-Methyl-6-tert-butylphenol), 4,4'-
Thiobis (2-methyl-6-tert-butylphenol), 4,4'-thiobis (5-methyl-6-tert-butylphenol), 4,4'-thiobis (2-chloro-)
6-tert-butylphenol), 4,4'-thiobis (2-methoxy-6-tert-butylphenol), 4,
4'-thiobis (2-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-m-cresol), 1- [α-methyl-α- (4'-
Hydroxyphenyl) ethyl] -4- [α ', α'-bis (4 "-hydroxyphenyl) ethyl] benzene,
1,1,3-tris (2-methyl-4-hydroxy-5)
-Cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy -3, 3 ', 5,
5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3 ', 5,5'-tetramethyldiphenyl sulfone, 2,2-bis (4-hydroxy-3,5
-Dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,
Hindered phenol compounds such as 2-bis (4-hydroxy-3,5-dimethylphenyl) propane, N,
N'-di-2-naphthyl-p-phenylenediamine,
2,2'-methylenebis (4,6-di-tert-butylphenyl) sodium phosphate and the like can be mentioned.

In the present invention, the method for forming the heat-sensitive recording layer is not particularly limited, and suitable examples include air knife coating, varibar blade coating, pure blade coating, rod blade coating, short dwell coating, curtain coating and die coating. The coating liquid for the recording layer is applied and dried on a support such as paper, plastic film, synthetic paper, and non-woven fabric by various coating methods, and then the coating liquid for the protective layer is applied and dried on the recording layer. It is formed. The support may be provided with an undercoat layer or an anchor coat layer,
A pearl pigment may be contained in these layers as long as the effect of the present invention is not impaired. Of course, a transparent support or a colored support may be used. The coating amount of the coating liquid for the recording layer is ² to 12 g / m ^{2 on} a dry weight basis, preferably 3 to 1
It is adjusted in the range of about 0 g / m ² .

In the heat-sensitive recording material of the present invention, a protective layer may be provided on the heat-sensitive recording layer or on the layer containing a pearl pigment for the purpose of improving the storability of recorded images against chemicals. is there. The protective layer is composed mainly of a binder made of a water-soluble or water-dispersible polymer compound. Specific examples of the binder include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxy modified polyvinyl alcohol, acetoacetyl group modified polyvinyl alcohol, silicon modified polyvinyl alcohol, diisobutylene. Maleic anhydride copolymer salt, styrene
Maleic anhydride copolymer salt, ethylene / acrylic acid copolymer salt, styrene / acrylic acid copolymer salt, styrene /
Examples thereof include a butadiene copolymer emulsion, a urea resin, a melamine resin, an amide resin, and a polyurethane resin. Among them, acetoacetyl group-modified polyvinyl alcohol and carboxy-modified polyvinyl alcohol are particularly preferably used because they can form a strong film. To be

If desired, a pigment may be added to the protective layer in order to further improve printability and sticking. Specific examples thereof include calcium carbonate and
Inorganic pigments such as zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, colloidal silica, styrene microballs, nylon powder, polyethylene powder, urea Examples include formalin resin fillers and organic pigments such as raw starch particles. It is generally desirable to adjust the amount used in the range of about 5 to 300 parts by weight with respect to 100 parts by weight of the binder component.

Further, in the coating liquid for the protective layer, if necessary, a lubricant such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, ester wax, etc., and a surfactant (dispersion such as sodium dioctylsulfosuccinate) (dispersion). Agent, wetting agent), defoaming agent,
Various auxiliaries such as water-soluble polyvalent metal salts such as potassium alum and aluminum acetate may be appropriately added. Further, in order to further improve the water resistance, a curing agent such as glyoxal, boric acid, dialdehyde starch, and an epoxy compound can be used in combination. The coating liquid for forming the protective layer is
Generally, water is used as the dispersion medium.

The protective layer coating solution thus prepared is coated on a heat-sensitive recording layer or a layer containing a specific pigment by a suitable coating device, but it is generally 0.3 to 10 g /
It is desirable that the amount is adjusted to m ² , preferably 0.5 to 7 g / m ² .

The heat-sensitive recording material of the present invention may be provided with two or more heat-sensitive recording layers which develop different color tones, or a heat-sensitive recording layer may be provided on the back surface. Furthermore, after applying each layer, smoothing treatment such as super calendering is applied,
Alternatively, various well-known techniques in the field of heat-sensitive recording material production may be used as necessary, such as applying a pressure-sensitive adhesive treatment to the back surface of the recording material to form an adhesive label, or providing a magnetic recording layer on the back surface of the recording material to form a thermosensitive magnetic recording material. Can be added.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Unless otherwise specified, "parts" and "%" in the examples mean "parts by weight" and "% by weight", respectively.

Example 1 Formation of Intermediate Layer Calcined clay [Product name: Ansilex, manufactured by EMC] 1
A composition comprising 00 parts, 15 parts of a styrene-butadiene latex (solid concentration 50%), 30 parts of a 10% aqueous solution of polyvinyl alcohol, and 200 parts of water was mixed and stirred to prepare an intermediate layer coating liquid. 50 g of the obtained coating liquid /
An intermediate layer was formed by coating and drying so that the coating amount after drying was 7 g / m ^{2 on} a high-quality paper of m ² .

Preparation of Solution A 10 parts of 3-di (n-butyl) amino-6-methyl-7-phenylaminofluorane, 20 parts of 1,2-di (3-methylphenoxy) ethane, 5% aqueous solution of methylcellulose 5 Parts and 40 parts of water were pulverized with a sand mill until the average particle size became 0.5 μm. Preparation of Solution B A composition consisting of 20 parts of 4-hydroxy-4′-isopropoxydiphenylsulfone, 5 parts of a 5% aqueous solution of methylcellulose, and 30 parts of water was pulverized with a sand mill until the average particle diameter became 1.0 μm.

Formation of Thermosensitive Recording Layer 75 parts of solution A, 55 parts of solution B, fine particle silicon oxide (oil absorption 18
0cc / 100g) 15 parts, polyvinyl alcohol 2
A coating solution prepared by mixing 50 parts of 0% aqueous solution and 95 parts of water with stirring was applied and dried on the above-mentioned intermediate layer so that the coating amount after drying was 5 g / m ² , to form a thermosensitive recording layer.

Formation of Inorganic Pearl Pigment Layer Inorganic pearl pigment [trade name: Iriodin 205, titanium oxide coating rate 43%, particle size 10 to 60 μm, manufactured by Merck Japan Co., Ltd.] 60 parts, pulverized paraffin wax with low melting point components cut ( Product name: Hydrin E-139, melting point: 7
5 ° C, solid content 30%, Chukyo Yushi Co., Ltd. 65 parts, polyvinyl alcohol and (acrylamide / acrylic acid derivative /
Graft copolymer with acrylonitrile) copolymer [Brand name: Polymalon 2000, solid concentration 15%, Arakawa Chemical Co., Ltd.] 130 parts, sodium di-2-ethylhexyl sulfosuccinate [Brand name: Rapisol B-80, NOF Corporation] Manufactured by the company] 0.1 part, 0.2 part antifoaming agent (solid concentration 15%),
A coating solution obtained by mixing and stirring 200 parts of water with water was applied and dried on the heat-sensitive layer so that the coating amount after drying was 3 g / m ² , to form an inorganic pearl pigment layer.

Formation of Protective Layer Graft copolymer of polyvinyl alcohol and (acrylamide / acrylic acid derivative / acrylonitrile) copolymer [trade name: Polymalon 2000, solid concentration 15%,
Arakawa Chemical Co., Ltd.] 330 parts, aluminum hydroxide [trade name: Hydilite H-42, average particle size 1 μm, Showa Denko KK] 50 parts, zinc stearate 30% aqueous dispersion 3
0 parts, sodium di-2-ethylhexyl sulfosuccinate [trade name: Ravisol B-80, manufactured by NOF Corporation] 2
Parts, 1 part of a defoaming agent (solid concentration 15%), and 340 parts of water were mixed and prepared so that the coating amount after drying on the above inorganic pearl pigment layer would be ² g / m ^2. After coating and drying to form a protective layer, smoothing treatment was carried out with a super calender to obtain a heat sensitive recording material.

Comparative Example 1 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the inorganic pearl pigment layer was not provided.

[Example 2] Crushed paraffin wax from which low-melting-point components have been cut A amide stearic acid emulsified product (trade name: High Micron G instead of Hydrin E-139)
-270, melting point 100 ° C., solid content 21.5%, manufactured by Chukyo Yushi Co., Ltd. was used to obtain a thermosensitive recording medium in the same manner as in Example 1.

[Example 3] Crushed paraffin wax from which low-melting-point components were cut A parabenzyl biphenyl emulsified product (trade name: Highmicron G-330, melting point 86 ° C, solid content 35%, Chukyo, instead of hydrin E-139) A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the oil and fat company) was used.

[Example 4] Paraffin wax crushed product in which low-melting-point components were cut Instead of hydrin E-139, paraffin wax crushed product (trade name: Hydrin P-
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that No. 7, melting point 54 ° C., solid content 30%, manufactured by Chukyo Yushi Co., Ltd.) was used.

Example 5 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the paraffin wax pulverized product Hydrin E-139 from which the low melting point component was cut was not used.

Example 6 In the preparation of solution A of Example 1, 3-di (n-butyl) amino-6-methyl-7-phenylaminofluorane was replaced with 3-diethylamino-7-chlorofluorane. A thermosensitive recording layer was formed in the same manner as in Example 1 except that it was used. Furthermore, instead of the inorganic pearl pigment Iriodin 205, an inorganic pearl pigment [trade name:
Iriodin 235, titanium oxide coverage 57%, grain size 10
˜60 μm, manufactured by Merck Japan Ltd.] was used to obtain a thermosensitive recording medium in the same manner as in Example 1.

Comparative Example 2 A thermal recording material was obtained in the same manner as in Example 6 except that the inorganic pearl pigment layer was not provided.

[Example 7] The same procedure as in Example 1 was carried out except that after forming the heat-sensitive recording layer in Example 1, a protective layer was provided on the heat-sensitive recording layer, and then the following pearl pigment layer was formed. I got a record. Formation of pearl pigment layer Inorganic pearl pigment [Product name: Iriodin 205, titanium oxide coating rate 43%, particle size 10 to 60 μm, manufactured by Merck Japan Ltd.] 30 parts, ground paraffin wax crushed product (trade name: Hydrin) E-139, melting point: 7
Offset ink containing a pearl pigment obtained by mixing and dispersing a composition consisting of 65 parts at 5 ° C., a solid content of 30%, manufactured by Chukyo Yushi Co., Ltd.) and 100 parts of an offset ink medium on the protective layer at a coating amount of 2 g / m ² To obtain a thermosensitive recording medium.

Example 8 Formation of Thermosensitive Recording Layer and Protective Layer In preparation of solution A, 3-di (n-butyl) amino-6- was used.
3, instead of methyl-7-phenylaminofluorane
A protective layer was formed in the same manner as in Example 7 except that 3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide was used. Formation of Inorganic Pearl Pigment Layer In the formation of the inorganic pearl pigment-containing layer of Example 7, instead of the inorganic pearl pigment Iridion 205, an inorganic pearl pigment [trade name: Iriodin 320, titanium oxide coverage 38
%, Iron oxide coating rate 4%, particle size 10 to 60 μm, manufactured by Merck Japan Co., Ltd., and a coating liquid using an acrylic clear lacquer instead of the offset ink medium is coated on the above protective layer at a coating amount of 2 g / A thermal recording material was obtained by printing so as to obtain m ² .

Comparative Example 3 A thermosensitive recording medium was obtained in the same manner as in Example 8 except that the inorganic pearl pigment layer was not provided.

The 11 kinds of heat-sensitive recording materials thus obtained were recorded by NTTFAX-20R, and the hue and vividness of the recorded image thus obtained are shown in Table 1. [Evaluation of sharpness of recorded image] A: The outline of the recorded image is clear. ◯: The recorded image is clear, but the contour is slightly blurred. X: The recorded image looks like haze.

[0045]

[Table 1]

[0046]

As is clear from the results of [Table 1], the thermosensitive recording medium of the present invention has a recorded image of a hue which cannot be obtained by the conventional color development by the reaction between the leuco dye and the color former. It was a recording material that can obtain Further, when a pearl pigment and a heat-fusible substance were used in combination, a clearer recorded image was obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiko Ishida 4-3-1 Jōkoji, Amagasaki City, Hyogo Kanzaki Paper Mill Kanzaki Mill

Claims (2)

[Claims] 1. A thermosensitive recording medium comprising a support and a thermosensitive recording layer containing a colorless or light-colored basic dye and a coloring agent, wherein a layer containing an inorganic pearl pigment is provided on the thermosensitive recording layer. A heat-sensitive recording material characterized by the following. 2. A heat-sensitive recording material according to claim 1, wherein the layer containing the inorganic pearl pigment further contains a heat-fusible substance.