JPH11245513A - Thermal recording medium - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a thermosensitive recording medium having a metallic luster or having a metallic luster of any color. Kind Code: A1 A thermosensitive recording medium comprising a support having a layer mainly composed of a metal powder and an acidic substance provided on one surface thereof, and a layer mainly composed of a leuco dye provided on the layer. A heat-sensitive recording medium comprising a layer mainly containing the leuco dye and a protective layer mainly containing a water-soluble polymer and / or a synthetic resin emulsion or a protective layer mainly containing an ultraviolet curable resin. Thermal recording in which a protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion is provided on a layer mainly composed of the leuco dye, and a second protective layer mainly composed of an ultraviolet curable resin is further provided. body. Further, a layer mainly containing the metal powder and the organic acid, a layer mainly containing a leuco dye, a protective layer mainly containing a water-soluble polymer and / or a synthetic resin emulsion,
Alternatively, a thermosensitive recording medium is provided in which at least one of the protective layers mainly composed of an ultraviolet curable resin contains a colored dye or pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording medium capable of recording an image by a thermosensitive recording system.

[0002]

2. Description of the Related Art In general, a thermosensitive recording medium comprises a support and a thermosensitive coloring layer formed on the support. The thermosensitive coloring layer is heated by a thermal head, a hot pen, a laser beam or the like to obtain a thermosensitive coloring. The coloring agent in the layer is reacted instantaneously to form a recorded image. For example, according to JP-B-43-4160 and JP-B-45-14039, a color-forming reaction between a leuco dye and an acidic substance is performed. The thermal recording medium used is one that has been widely known.

[0003] Such a thermosensitive recording medium has such advantages that a recorded image can be formed by a relatively simple apparatus, maintenance is easy, and no noise is generated at the time of recording. , Facsimile, measuring recorder, computer and other terminal printers, automatic ticket vending machines, bar code labels, etc.

In particular, in recent years, the use of heat-sensitive recording materials has been expanding to various types of tickets, receipts, ATMs for banks, gas and electricity meter reading, and the like. Therefore, characteristics that were not required in the past have been demanded. As one of them, there has been a demand to give a metallic luster to the background portion in order to give a design and a high-grade feeling.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermosensitive recording medium having the above-mentioned metallic luster or a metallic luster of an arbitrary color.

[0006]

According to the heat-sensitive recording material of the present invention, a layer mainly composed of a metal powder and an acidic substance is provided on one surface of a support, and a layer mainly composed of a leuco dye is formed on the layer. It is obtained by providing.

According to the study of the present inventors, in order to obtain a metallic luster, in a configuration in which a thin metal layer is provided on a support by means such as metal deposition, sputtering, or CVD, a heat-sensitive material provided on the thin metal layer is used. Since the metal thin layer was viewed from the color forming layer side, no metallic luster could be obtained. As a result of various experiments for this purpose, it was found that it is necessary that the layer exhibiting metallic luster diffusely reflect light.

Further, if a layer containing only metal powder as a main component without an acidic substance is provided in advance and then a thermosensitive coloring layer is provided, a metallic luster is obtained, but a leuco dye and an acidic substance coexist in the thermosensitive coloring layer. For this reason, the thickness of the recording layer is increased, and there is a problem that the level of metallic luster is reduced and background fogging is likely to occur.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, each element constituting the present invention will be described in more detail. Aluminum, zinc, tin, silver, gold, etc. are exemplified as the metal powder constituting the layer mainly composed of the metal powder and the acidic substance of the present invention. Aluminum is particularly preferred from the viewpoint of the above.

As the aluminum powder pigment and the aluminum paste (paint containing aluminum powder) as a form to be applied to the support, JIS K5906-
1991, Convertec August 1995, p. 46-
There is a detailed description on page 49 and the like, and known techniques can be employed.

[0011] Specific names of the aluminum paste used for such a purpose include solvent-based pastes TD120T, TD180T, T
D200T, TD280T, aqueous paste 93-207
0, 93-2071, 93-2072, 93-207
3, 93-2074, HR, CR manufactured by Asahi Kasei Corporation
-808CM, SF-808C, AW-7000R, A
W-808C and the like.

The acidic substance is a solid at ordinary temperature, is a substance which melts by heating and comes into contact with the leuco dye compound to become a color developer, and is a phenol derivative, an aromatic carboxylic acid derivative, N, N'-diarylthio. Polyvalent metal salts such as urea derivatives and zinc salts of organic compounds can be used.

Specifically, 4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o
-Methylphenol), 4,4'-secondary-butylidenebisphenol, 4,4'-isopropylidenebis (2-tert-butylphenol), 4,4'-cyclohexylidenediphenol, 4,4'-isopropylidenebis (2-chlorophenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-2-methylphenol),

4,4'-diphenol sulfone, 4-isopropoxy-4'-hydroxyphenyl sulfone,
Benzyloxy-4′-hydroxydiphenyl sulfone, 4,4′-diphenol sulfoxide, 2,2-bis (3-allyl-4-hydroxyphenyl) sulfone,
isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocaquitenate, stearyl gallate, lauryl gallate, octyl gallate,

1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-
(Hydroxyphenylthio) -3-oxapentane, 1,
3-bis (4-hydroxyphenylthio) -propane,
1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N′-diphenylthiourea,
N, N′-di (m-chlorophenyl) thiourea,

Salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, zinc, aluminum, calcium of hydroxynaphthoic acid, etc. Metal salt of bis (4-hydroxyphenyl)
Acetic acid methyl ester, bis (4-hydroxyphenyl)
Benzyl acetate, bis (4-hydroxyphenyl) acetic acid butyl ester,

1,3-bis (4-hydroxycumyl) benzene, 1,4-bis (4-hydroxycumyl) benzene, 2,4'-diphenol sulfone, 3,3'-diallyl-4,4 '-Diphenol sulfone, α, α-bis (4-hydroxyphenyl) α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S and the like are used.

As a binder for fixing a layer mainly composed of a metal powder and an acidic substance on a support, an aqueous binder is used when an aqueous paint is used.
Hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, water-soluble binders such as styrene-maleic anhydride copolymer, ethylene-maleic anhydride copolymer, styrene-butadiene copolymer, acrylonitrile -Butadiene copolymer,
And hydrophobic resin emulsions such as methyl acrylate-butadiene copolymer.

When a solvent-based paint is used, a resin soluble in an organic solvent such as xylene, toluene, isopropyl alcohol, methyl ethyl ketone, methyl isobutyl ketone, mineral spirit, and solvent naphtha can be used. PVC / vinyl acetate copolymer, PVC / vinyl acetate / maleic acid copolymer, polyurethane, saturated polyester, polyester polyurethane, epoxy resin, phenoxy resin, nitrocellulose, melamine resin, chlorinated polyethylene, etc., and a crosslinking agent. And polyisocyanate.

In the present invention, a layer mainly composed of a metal powder and an acidic substance, a layer mainly composed of a leuco dye, a protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion, or a UV-curable layer By adding various coloring dyes / pigments to at least one of the protective layers containing a resin as a main component, it is possible to obtain a thermosensitive recording material having a metallic luster colored in an arbitrary color. The coloring dye / pigment used here is not particularly limited, and may be selected from those usually used in the field of papermaking or printing.

Examples of the method for providing a layer containing a metal powder and an acidic substance as main components of the present invention include a coating method such as a rod coater and a blade coater, and a printing method such as gravure printing, letterpress printing, and lithographic printing. . These are used properly depending on the properties of the paint or ink constituting the layer.

As the leuco dye used in the layer mainly containing a leuco dye provided on the layer mainly containing the metal powder and the acidic substance of the present invention, conventionally known leuco dyes are used. Show. Leuco dyes are colorless or light-colored substances that react with acidic substances to develop color,

(1) Triarylmethane compounds, for example, 3,3-bis (p-dimethylaminophenyl)
-6-dimethylaminophthalide (crystal violet lactone), 3- (p-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl)
Phthalide, 3- (p-dimethylaminophenyl) -3-
(2-phenylindol-3-yl) phthalide, 3,
3-bis- (p-ethylcarbazol-3-yl) -3
-Dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5-dimethylaminophthalide and the like;

(2) Diphenylmethane compounds, for example, 4,4-bis-dimethylaminobenzhydrin benzyl ether, N-halophenylleucouramine, N-2,4,5-trichlorophenylleucouramine and the like;

(3) Xanthene compounds For example, rhodamine B-anilinolactam, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-butylaminofluoran, 3-diethylamino-7- (2- Chloroanilino) fluoran, 3
-Diethylamino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3-ethyl-tolylamino-6-methyl-7-anilinofluoran, 3-cyclohexyl- Methylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7- (β-ethoxyethyl) aminofluoran, 3-diethylamino-6-chloro-7-
(Γ-chloropropylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-N
-Cyclohexyl-N-methylamino-6-methyl-7
-Anilinofluoran, 3-diethylamino-7-phenylfluoran, 3- (N-isoamyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7 -Anilinofluoran and the like;

(4) Thiazine compounds such as benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue and the like; (5) Spiro compounds such as 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran and 3- Benzylspiro-
Dinaphthopyran, 3-methylnaphtho- (3-methoxy-
Benzo) -spiropyran and the like; compounds known in the field of thermal recording paper. Further, a mixture of these is used, and is appropriately selected in consideration of desired characteristics depending on the application.

As the binder used in the layer mainly containing the present leuco dye, the above-mentioned aqueous binder used for the layer mainly containing the metal powder and the acidic substance can be used.

In the layer containing leuco dye as a main component, if necessary, other additives such as inorganic or organic pigments such as clay, calcium carbonate, synthetic silica, aluminum hydroxide, talc, titanium oxide, zinc oxide, etc. An antioxidant for stabilization, an ultraviolet absorber, a water-proofing agent for improving water resistance, a surfactant, conventionally used waxes, metal salts of higher fatty acids, and the like can be added.

For the purpose of promoting color development, the following heat-fusible substances are added to a layer mainly containing a metal powder and an acidic substance or a layer mainly containing a leuco dye or between two layers. You may.

For example, fatty acids such as stearic acid and behenic acid, stearic acid amide, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β
-Naphthoic acid phenyl ester, 1-hydroxy-2-
Naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, diphenyl carbonate, terephthalic acid dibenzyl ester, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxoinaphthalene, 1,2-bis (phenoxy) ethane, 1,2- (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane,
1,4-bis (phenoxy) butane, 1,4-bis (phenoxy) -2-butene, dibenzoylmethane, 1,4
-Bis (phenylthio) butane, 1,4-bis (phenylthio) -2-butene,

1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-aryloxybiphenyl, p- Propargyloxybiphenyl, dibenzoyloxymethane, 1,
3-dibenzoyloxypropane, dibenzyldisulfide, 1,1-diphenylethane, 1,1-diphenylpropanol, p- (benzyloxy) benzyl alcohol, 1,3-diphenoxy-2-propanol, N-
Octadecylcarbonyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene and the like are exemplified.

On the layer containing leuco dye as a main component, PV
A, modified PVA, starch, and other known overcoating agents known in the art by providing a protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion or a protective layer mainly composed of an ultraviolet curable resin. This is preferable because a more stable recording medium can be obtained.

Further, by providing a second protective layer mainly composed of an ultraviolet curable resin on the protective layer mainly composed of the water-soluble polymer and / or the synthetic resin emulsion, glossy and mechanical pressure can be obtained. It is possible to obtain an excellent thermosensitive recording medium which is not affected by

The UV-curable resin is described in detail in published books and magazines, such as “Taiseisha: Light / Radiation Curing Technology,” but in short, it is a photopolymerizable monomer, prepolymer, or It is obtained by polymerizing by irradiating ultraviolet rays to an ultraviolet-curable resin composition containing polymers and a photopolymerization initiator as essential components.

The monomer and the prepolymer or polymer are compatible and have copolymerizability. As the prepolymer, unsaturated polyester, epoxy, acrylic, various polyesters and the like can be used, and as the monomer, various ethylene derivatives can be mentioned.

The support used in the present invention is not particularly limited, and examples thereof include high quality paper, recycled paper, matte paper, oil resistant paper, coated paper, art paper, cast coated paper, finely coated paper, and resin laminated paper. And polyolefin-based synthetic paper, synthetic fiber paper, synthetic resin film and the like can be used as appropriate.

The method for forming a layer mainly composed of a metal powder and an acidic substance, a layer mainly composed of a leuco dye, and a protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion on a support is as follows. , Known coating machines, such as air knife coater, various blade coater, roll coater,
A curtain coater or the like can be used, and the coating amount of the layer containing a leuco dye as a main component is not particularly limited, but it is generally applied in a dry weight of about 1 to 15 g / m ² , preferably about ² to 10 g / m ^2. You. The protective layer is applied in a range of about 1 to 10 g / m ² , preferably about ² to 5 g / m ² . It is also effective to improve the image quality by performing a smoothing process using a super calendar after coating.

Protective layer mainly composed of UV-curable resin
Is a printing method such as flexo, offset, gravure, etc.
It is common to provide. About 0.5 ~
7g / m ^TwoDegree, preferably 1-4 g / m^TwoGood to do
No.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The constitution of a thermal recording medium of the present invention formed using the above-mentioned materials is conceptually illustrated in FIGS. That is, in FIG. 1, 1 is a support, 2 is a layer mainly composed of a metal powder and an acidic substance, and 3 is a layer mainly composed of a leuco dye. FIG. 2 shows a configuration in which 4 protective layers are added to FIG. FIG. 3 shows a configuration obtained by adding the ultraviolet ray effect type resin protective layer 5 to FIG.

The present invention will be described more specifically with reference to production examples. Parts and% indicate the solid component, the active ingredient, or the weight-based value of the liquid amount of a predetermined concentration. (Example 1) Preparation of "Layer containing metal powder and acidic substance as main components" Solvent-based aluminum paste (TD120T manufactured by Toyo Ink Industries, Ltd.) 50 parts Bis- (3-allyl-4-hydroxyphenyl) -sulfone 10 parts toluene 30 parts were mixed to prepare a coating liquid, basis weight 60 g / coating amount after drying to a polyolefin synthetic paper m ² is applied and dried such that the 5 g / m ² metal powder and an acidic substance Was provided as a main component.

Preparation of “Layer Dye-Based Layer” Preparation of Leuco Dye Solution 3-Di (N-butylamino) -7- (2-chloroanilino) fluoran ... 10 parts 20% polyvinyl alcohol solution (Kuraray Povar 105) 10 parts Water 20 parts This composition was pulverized by a sand mill until the average particle diameter became 0.8 μm. 20% polyvinyl alcohol solution
30 parts of Kuraray Povar 105 (manufactured by Kuraray), 5 parts of silica (manufactured by Mizusawa Chemical) and 5 parts of a 30% zinc stearate dispersion (D-523 manufactured by Chukyo Yushi) are mixed and stirred to obtain a leuco dye solution. Was. The obtained coating liquid was applied and dried on a layer mainly composed of a metal powder and an acidic substance so as to have a dry weight of 2 g / m ² . Thus, the sample of Example 1 was obtained.

Example 2 Example 1 was repeated except that silica and zinc stearate were omitted from the leuco dye solution composition of Example 1.
A recording medium A was obtained in exactly the same manner as described above, and the following protective layer was formed thereon.

Formation of protective layer: 400 parts of a 10% carboxy-modified polyvinyl alcohol solution (T-215, manufactured by Nippon Gosei Co., Ltd.), silica (P-5)
27 Mizusawa Chemical Co., Ltd. 10 parts, 30% zinc stearate dispersion (D-523 made by Chukyo Yushi), 10 parts of glyoxal, and water 200 parts were mixed and stirred to obtain a coating liquid for a protective layer. The obtained coating liquid was applied and dried on the recording medium A so that the dry weight was 2 g / m ^2, and a sample of Example 2 was obtained.

(Example 3) An ultraviolet-curable resin (N-181 manufactured by Nippon Kayaku Co., Ltd.) was further provided on the recording medium of Example 2.
5) was applied at 1 g / m ² and irradiated with ultraviolet rays to obtain a sample of Example 3.

Example 4 Aqueous aluminum paste (93-2072, manufactured by Toyo Aluminum Co., Ltd.) instead of TD120T of Example 1 30 parts Bis- (3-allyl-4-hydroxyphenyl) -sulfone 10 parts Acrylic emulsion manufactured by Johnson Polymer Co., Ltd. Acrylic emulsion john 711: 50 parts Ethanol: 10 parts Water: 10 parts An aqueous coating solution was prepared, and the coating amount after drying was 3 g /
A sample of Example 4 was obtained in the same manner as in Example 1, except that a layer mainly composed of a metal powder and an acidic substance was obtained by applying and drying to obtain m ² .

Example 5 An aqueous dye (Kayafect Violet manufactured by Nippon Kayaku) was added to the aqueous coating solution of Example 4 in an amount of 0.5%.
A sample of Example 5 was obtained in the same manner as in Example 4, except for adding a portion.

(Printing test) A commercially available label printer (Nippon Shinbo XP-
6250). It was confirmed that all of the samples obtained in Examples 1 to 5 were able to perform clear black printing on the surface having a vivid metallic luster.

[0048]

As described above, by adopting the constitution of the present invention, a heat-sensitive recording medium having a metallic luster and having a design property can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram of a thermosensitive recording medium of the present invention.

FIG. 2 is an example in which a protective layer is provided on the thermosensitive recording medium of FIG.

FIG. 3 is an example in which a second protective layer made of an ultraviolet curable resin is provided on the thermosensitive recording medium of FIG. 2;

[Explanation of symbols]

 1: Support 2: Layer mainly composed of metal powder and acidic substance 3: Layer mainly composed of leuco dye 4: Protective layer 5: UV-curable resin layer

Claims (4)

[Claims] 1. A thermosensitive recording medium comprising: a support having a layer mainly composed of a metal powder and an acidic substance provided on one side thereof; and a layer mainly composed of a leuco dye provided on the layer. 2. A protective layer mainly comprising a water-soluble polymer and / or a synthetic resin emulsion or a protective layer mainly comprising an ultraviolet-curable resin is provided on the layer mainly containing the leuco dye. The heat-sensitive recording material according to claim 1, wherein 3. A protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion is provided on the layer mainly composed of the leuco dye, and a second protective layer mainly composed of an ultraviolet curable resin. 2. The heat-sensitive recording medium according to claim 1, further comprising: 4. A layer mainly composed of said metal powder and an organic acid, a layer mainly composed of a leuco dye, a protective layer mainly composed of a water-soluble polymer and / or a synthetic resin emulsion, or an ultraviolet curable resin. 4. The heat-sensitive recording material according to claim 1, wherein at least one of the protective layers as a main component contains a colored dye or pigment.