JPH1148610A - Heat-sensitive recording body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-sensitive recording body which is excellent in recording-running property by providing an uppermost layer of a specified weight of which the major component is an interfacial active agent or a lubricant, on a recording layer. SOLUTION: For a heat-sensitive recording body wherein a recording layer containing a leuco dye and a color developing agent on a supporting body, an uppermost layer of 0.001-0.1 g/m<2> (preferably, 0.005-0.05g/m<2> ) of which the major component is a surfactant or a lubricant, is provided on the recording layer. As the content for the surfactant or the lubricant, it is 50 wt.% or higher for the uppermost layer, and preferably 80 wt.% or higher. As the leuco dye, e.g., 3,3-bis(pdimethylaminophenyl)-6-dimethylaminophthalide, 3-(4-dimethylamino-2 methylphenyl)-6-dimethylaminophthaliole, etc., are counted, and also, as the color developing agent, e.g., 4,4-isopropylidenediphenol, bis(2-tert-butyphenol), 4,4-sec-butylidenediphenol, etc., are counted.

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 recording material having excellent recording running properties.

[0002]

2. Description of the Related Art A thermosensitive recording medium is known which uses a color development reaction between a leuco dye and a coloring agent to contact a coloring substance by heat to obtain a recorded image. Recently, with the remarkable progress of the thermal recording method, the fields of use and forms have been diversified, and not only as a recording medium for thermal facsimile and thermal printer, but also as a magnetic thermal recording medium or POS.
The use for new applications such as labels, ticket cards that require counterfeiting prevention, prepaid cards, and sealless period is also increasing rapidly.

Further, a thermosensitive recording medium using a film as a support is excellent in recording image quality, and is used as a recording medium for medical use, OHP, or drawing. But,
Such a thermosensitive recording medium has a problem that sticking easily occurs between the thermal head and the uppermost surface of the thermosensitive recording medium during recording. A heat-sensitive recording material containing a lubricant in the uppermost layer on the recording layer side in order to enhance the recording running property is disclosed in JP-A-57-123.
No. 088, JP-A-1-178486 and JP-A-3-49986, and a heat-sensitive recording material containing a surfactant in the uppermost layer is disclosed in JP-A-60-46295.
JP, JP-A-3-14787, JP-A-3-3-1
No. 44586, because the uppermost layer containing such a lubricant or a surfactant is to be used together with an adhesive, or because the coating amount of the uppermost layer exceeds at least 0.1 g / m ² . In particular, when the support is a film, sticking may occur during recording.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermosensitive recording medium having excellent recording running properties.

[0005]

As one means for solving the above-mentioned problems, the present invention provides at least a thermosensitive recording medium having a recording layer containing a leuco dye and a colorant provided on a support. The uppermost layer of 0.001 to 0.1 g / m ² containing a surfactant or a lubricant as a main component is provided on the recording layer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a thermosensitive recording medium having at least a recording layer containing a leuco dye and a colorant on a support, wherein the recording layer contains a surfactant or a lubricant as a main component. characterized by providing a top layer of 0.001 to 0.1 g / m ^2, not obtained the effect of improving the recording runnability by sticking resistance when the top layer is less than 0.001 g / m ^2, also 0. If it exceeds 1 g / m ² , conversely, there is a possibility that the recording head may adhere to the recording head to make it impossible to obtain a uniform recorded image, or the recording density may be reduced due to the desensitizing effect of the surfactant or the lubricant. 0.005-
About 0.05 g / m ² is more preferable. In the uppermost layer containing a surfactant as a main component, an antistatic effect can be further obtained. As the content of the surfactant or the lubricant,
50% by weight or more based on the uppermost layer, preferably 80% by weight.
% By weight or more.

Conventionally, an adhesive is provided in the uppermost layer provided on the recording layer together with an adhesive to enhance the preservability of the recorded image and the recording running property.
Thermal recording media containing a surfactant or a lubricant are well known, but there is a problem that sticking is likely to occur during recording, especially when a film is used as a support.

However, the top layer of 0.001 to 0.1 g / m ² containing a surfactant or a lubricant as a main component,
Due to the extremely thick film, it is hard to be peeled off from the thermal head during recording, and an effect excellent in sticking resistance can be obtained. Such an uppermost layer is preferably provided on a protective layer mainly composed of a film-forming adhesive provided between the recording layer and the uppermost layer.

The surfactant in the present invention may be any of anionic, nonionic and cationic.
In particular, nonionic ones are preferable because they have little effect on the thermal head. Examples of the anionic surfactant include a fatty acid salt, an alkyl phosphate, an alkyl sulfate, an alkyl sulfosuccinate, and an alkylbenzene sulfonate. However, examples of the salt include monovalent salts such as sodium, potassium, lithium, and ammonium. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene derivative, polyoxyethylene sorbitol fatty acid ester, and polyoxyethylene sorbitan fatty acid ester. Examples of the cationic surfactant include an alkylamine salt, a quaternary ammonium salt, an amine oxide, and an alkyl betaine.

[0010] As the lubricant, zinc stearate,
Polyvalent metal salts of water-insoluble fatty acids such as calcium stearate and calcium oleate; waxes such as polyethylene wax, ester wax, paraffin wax and carnauba wax; silicone oils such as silicone oil, epoxy-modified silicone oil, and carboxy-modified silicone oil; And alkyl phosphates.

The uppermost layer is generally coated with a coating liquid for the uppermost layer containing water as a medium and containing a surfactant or a lubricant dissolved or dispersed in water as a main component, using an air knife coating, a variver blade coating, a pure blade. By a suitable coating method such as coating, rod blade coating, short dwell coating, curtain coating, die coating, spraying method, etc., it is formed by directly coating on the recording layer or by drying on a protective layer provided on the recording layer. . In particular, a spray coating method is preferable since a uniform coating surface can be obtained even when the coating amount is 0.1 g / m ² or less. In addition, the application amount of the uppermost layer is determined from the consumption amount of the coating solution for the uppermost layer.

Various known leuco dyes and colorants can be used as the leuco dye and colorant contained in the recording layer. Specific examples of koiko dyes include, for example, the following. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2-methylphenyl) -3- (4-dimethylaminophenyl) -6-dimethylaminophthalide, 3-
Diethylamino-7-dibenzylaminofluoran, 3
-Cyclohexylamino-6-chlorofluoran, 3-
Diethylamino-6-methyl-7-chlorofluoran,
3-diethylamino-7-chlorofluoran, 3-diethylamino-7-anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-7 -(M-trifluoromethylanilino) fluoran, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7
-Anilinofluoran, 3-di (n-butyl) amino-
6-methyl-7-anilinofluoran, 3-di (n-pentyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino)
Fluoran, 3-di (n-butyl) amino-7- (o-
Chloroanilino) fluoran, 3-di (n-butyl) amino-7- (o-fluoroanilino) fluoran, 3-
(N-ethyl-p-toluidino) -6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-
7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3,3-bis [1- (4-
Methoxyphenyl) -1- (4-dimethylaminophenyl) ethylene-2-yl] -4,5,6,7-tetrachlorophthalide, 3,3-bis [1- (4-methoxyphenyl) -1- (4-pyrrolidinophenyl) ethylene-2
-Yl] -4,5,6,7-tetrachlorophthalide,
3,6, -bis (dimethylamino) fluorene-9-spiro-3 ′-(6′-dimethylamino) phthalide, 3-
(N-ethyl-N-2-tetrahydrofurfuryl) amino-6-methyl-7-anilinofluoran, 3- (4-
Dimethylamino) anilino-5,7-dimethylfluoran and the like

Of course, it is not limited to these,
If necessary, two or more kinds can be used in combination. The amount of the leuco dye used is about 5 to 35% by weight based on the total solid content of the recording layer.

Examples of the coloring agent include, for example, 4,4'-
Isopropylidene diphenol, bis (2-tert-butylphenol), 4,4′-sec-butylidene diphenol, 4-phenylphenol, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4 '-
Cyclohexylidenediphenol, 2,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4- Hydroxy-4′-methyldiphenylsulfone, 4-hydroxy-4′-benzyloxydiphenylsulfone, 3,4-dihydroxyphenyl-4′-methylphenylsulfone, hydroquinone monobenzyl ether, 4-hydroxybenzophenone,
1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4-bis [(4-hydroxyphenyl)
Isopropylidene] benzene, benzyl 4-hydroxybenzoate, 4-hydroxybenzoic acid-p-methoxybenzyl, phenolic compounds such as novolak-type phenolic resins, phenolic polymers, 4- [2- (p-methoxyphenoxy) ethyloxy] Zinc salicylate, 4- [3-
Zinc salt of a salicylic acid derivative such as (p-tolylsulfonyl) propyloxy] zinc salicylate, 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] zinc salicylate, Np-tolylsulfonyl-N'-phenylurea And compounds having a sulfamide bond in the molecule such as 4,4'-bis (p-tolylsulfonylaminocarbonylamino) diphenylmethane. Of course, the present invention is not limited to these, and two or more of them can be used as needed. The amount of the coloring agent used is about 10 to 70% by weight based on the total solid content of the recording layer.

In the recording layer, if necessary, pigments such as kaolin, calcium carbonate, amorphous silica, titanium oxide, aluminum hydroxide, calcined kaolin, zinc oxide, etc.
Stearic acid amide, ethylenebisstearic acid amide, m-terphenyl, oxalic acid di-p-methylbenzyl ester, oxalic acid di-p-chlorobenzyl ester, terephthalic acid dibenzyl ester, 1-hydroxynaphthoic acid phenyl ester, 1 , 2-di- (3-methylphenoxy) ethane, 1,2-diphenoxyethane,
Sensitizers such as 1-phenoxy-2-naphthoxyethane and p-benzylbiphenyl, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2 -Methyl-4-hydroxy-5-tert-butylphenyl) butane, N, N'-di-2-naphthyl-p-phenylenediamine, 2,2'-
Preservative improvers such as sodium methylenebis (4,6-di-tertbutylphenyl) phosphate, waxes such as carnauba wax, montan wax, paraffin wax, microcrystalline wax, polyethylene wax, and lubricants such as zinc stearate and calcium stearate. And a fluorescent dye, a coloring dye, a surfactant, a waterproofing agent, and the like.

The recording layer is generally composed of water as a medium, a leuco dye finely dispersed to an average particle diameter of about 0.1 to 3 μm, a coloring agent, an adhesive, and if necessary, a sensitizer and a storage stability improving agent. Are mixed and agitated to form a coating liquid for a recording layer, which is applied to one surface of a high-quality paper, a synthetic paper or a film and dried.

It is one of the preferable usages to provide a protective layer mainly composed of a film-forming adhesive between the recording layer and the uppermost layer. Examples of such an adhesive include starches such as oxidized starch, enzyme-modified starch, cation-modified starch, esterified starch, and etherified starch; cellulose derivatives such as methylcellulose, ethylcellulose, carboxymethylcellulose, methoxycellulose, and hydroxyethylcellulose; Part) polyvinyl alcohols such as saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, sodium polyacrylate, polyacrylamide, polyvinylpyrrolidone, acrylamide / acrylate copolymer,
Acrylic amide / acrylic acid ester / methacrylic acid copolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, water-soluble resin such as sodium alginate, gelatin, casein, polyacetic acid Vinyl, polyurethane, polyacrylate, styrene / butadiene resin, vinyl chloride
Water-dispersible resins such as vinyl acetate resins and ethylene / vinyl acetate resins are exemplified.

Further, pigments such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, kaolin, clay, calcined clay, amorphous silica, etc., and a crosslinking agent may be contained in the protective layer. Auxiliaries such as dispersants, defoamers, coloring dyes, fluorescent dyes, and ultraviolet absorbers can also be added.

The protective layer is formed, for example, by adding the above-mentioned auxiliary agent to a medium in which an adhesive having a film-forming property is dissolved or dispersed, while stirring, if necessary, and coating the protective layer coating solution with heat-sensitive recording. It is formed by coating and drying on the layer.

The recording layer and the protective layer include an air knife coating, a variver blade coating, a pure blade coating, a rod blade coating, a short dwell coating, a curtain coating,
It is formed by applying and drying a coating liquid by an application method such as die coating and gravure coating. The coating amount of the recording layer coating liquid is 1 to 20 g / m ² , preferably 2 to ²⁰ g / m ² in dry weight.
15 g / m is about ^2, the coating amount of the protective layer coating liquid for dry weight 1 to 7 g / m ² in, preferably 1.5 to 5 g / m ²
It is about.

On the protective layer, a coating liquid containing an electron beam or ultraviolet curable compound as a main component is further applied, and then a gloss layer cured by irradiation with an electron beam or ultraviolet light is provided. Between the provision of an intermediate layer to increase the recording sensitivity, the provision of an antistatic layer on the back side of the support, or after forming each layer, various calendering in the field of thermosensitive recording material such as super calendering Known techniques can be added as appropriate.

[0022]

The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. Further, unless otherwise specified, parts and% in the examples indicate parts by weight and% by weight, respectively.

Example 1 Preparation of Solution A 20 parts of 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran, 1,2-di- (3
-Methylphenoxy) ethane, a composition comprising 10 parts of methylcellulose, 20 parts of a 5% aqueous solution of methylcellulose, and 50 parts of water was pulverized by a sand mill until the average particle diameter became 1.0 μm to obtain a liquid A.

Solution B Preparation A composition comprising 20 parts of 4-hydroxy-4'-isopropoxydiphenyl sulfone, 20 parts of a 5% aqueous solution of methylcellulose, and 50 parts of water is pulverized by a sand mill until the average particle diameter becomes 1.0 μm. The solution B was obtained.

Preparation of Coating Solution for Recording Layer 100 parts of solution A, 100 parts of solution B, 20 parts of calcium carbonate slurry having a solid concentration of 60%, 20 parts of aluminum hydroxide slurry having a solid concentration of 60%, 13 parts of partially saponified polyvinyl alcohol % Of an aqueous solution, 20 parts of a 10% aqueous glyoxal solution, and 20 parts of water were mixed and stirred to obtain a coating liquid for a recording layer.

Preparation of Coating Solution for Protective Layer 150 parts of a 12% aqueous solution of acetoacetyl-modified polyvinyl alcohol, kaolin slurry 100 having a solid concentration of 60%
Of a 30% aqueous dispersion of zinc stearate, 1 part of a 10% aqueous solution of sodium dioctylsulfosuccinate, and 40 parts of a 5% aqueous solution of glyoxal were mixed and stirred to obtain a coating liquid for a protective layer.

Preparation of heat-sensitive recording medium On one surface of a high-quality paper having a basis weight of 80 g / m ² , the above-mentioned coating liquid for a recording layer and the coating liquid for a protective layer were applied in an amount of 6 g after drying.
/ M ² , and 3 g / m ² , after coating and drying, followed by a super calender treatment to form a recording layer and a protective layer sequentially. A sprayer (trade name: BIAS-700V) was coated on the protective layer with a coating liquid for the uppermost layer comprising a 10% aqueous solution of polyoxyethylene sorbitan monostearate so that the coating amount after drying was 0.02 g / m ^2. , Tokyo Copal Chemical Co., Ltd.) to form an uppermost layer.

Example 2 In the preparation of the heat-sensitive recording medium of Example 1, a 10% aqueous solution of polyoxyethylene alkyl ether was used instead of the coating liquid for the uppermost layer composed of a 10% aqueous solution of polyoxyethylene sorbitan monostearate. A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the coating solution for the uppermost layer was used.

Example 3 In the preparation of the thermosensitive recording medium of Example 1, a 10% dispersion of epoxy-modified silicone oil was used instead of the uppermost layer coating solution composed of a 10% aqueous solution of polyoxyethylene sorbitan monostearate. A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the coating solution for the uppermost layer was used.

Example 4 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the protective layer was not formed in the formation of the thermosensitive recording medium of Example 1.

Example 5 In the formation of the heat-sensitive recording medium of Example 1, the coating amount after drying of the coating liquid for the uppermost layer comprising a 10% aqueous solution of polyoxyethylene sorbitan monostearate was 0.02 g / m ^2. Instead, the coating amount after drying of the coating liquid for the uppermost layer composed of a 1% aqueous solution of polyoxyethylene sorbitan monostearate is 0.003 g / m ^2.
A thermosensitive recording medium was obtained in the same manner as in Example 1, except that

Example 6 In the formation of the thermosensitive recording medium of Example 1, the coating amount after drying of the coating liquid for the uppermost layer comprising a 10% aqueous solution of polyoxyethylene sorbitan monostearate was 0.02 g / m ^2. A thermosensitive recording medium was obtained in the same manner as in Example 1, except that the coating amount after drying of the coating liquid for the uppermost layer was changed to 0.09 g / m ² .

[Example 7] Preparation of heat-sensitive recording medium A coating solution for a recording layer and a coating solution for a protective layer of Example 1 were applied to one surface of a 100 μm-thick anchor-coated transparent polyethylene terephthalate film after drying. 6 each
After coating and drying to give g / m ² and 3 g / m ² , each was subjected to a super calender treatment to sequentially form a recording layer and a protective layer. After applying the following gloss layer coating solution at 1 g / m ² on the formed protective layer by using a gravure coater,
Providing a gloss layer cured by irradiating an electron beam with 3 Mrad,
Further, a coating liquid for the uppermost layer composed of a 10% aqueous solution of polyoxyethylene sorbitan monostearate was further applied and dried using a sprayer such that the coating amount after drying was 0.02 g / m ^2. A thermosensitive recording medium having an upper layer was obtained.

Preparation of Coating Liquid for Gloss Layer A composition comprising 90 parts of an electron beam-curable prepolymer (trade name: 78E204, manufactured by Mobil Sekiyu KK) and 10 parts of calcium carbonate was mixed by a roll mill to prepare a coating liquid for a gloss layer. Obtained.

Example 8 In the preparation of the thermosensitive recording medium of Example 1, instead of the uppermost layer coating solution composed of a 10% aqueous solution of polyoxyethylene sorbitan monostearate,
10% aqueous solution of polyoxyethylene alkyl ether 7
Part and polyvinyl alcohol (trade name: PVA10
5, Kuraray Co., Ltd.), and a thermosensitive recording medium was obtained in the same manner as in Example 1 except that a coating solution for the uppermost layer comprising 3 parts of a 10% aqueous solution was used.

Comparative Example 1 In the formation of the heat-sensitive recording medium of Example 1, the coating amount after drying of the coating liquid for the uppermost layer comprising a 10% aqueous solution of polyoxyethylene sorbitan monostearate was 0.02 g / m ^2. Instead of providing the uppermost layer so as to obtain a coating solution for the uppermost layer comprising a 0.1% aqueous solution of polyoxyethylene sorbitan monostearate so that the coating amount after drying is 0.0003 g / m ² , A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the above was provided.

COMPARATIVE EXAMPLE 2 In the formation of the thermal recording medium of Example 1, the coating amount for the uppermost layer comprising a 10% aqueous solution of polyoxyethylene sorbitan monostearate after drying was 0.02 g / m ^2. Instead of coating and drying using a sprayer to provide the uppermost layer, a coating solution for the uppermost layer composed of a 5% aqueous solution of polyoxyethylene sorbitan monostearate has a coating amount of 0.3 g / m3 after drying. ^A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the uppermost layer was formed by coating and drying using a bar coater so as to obtain No. 2.

Comparative Example 3 In forming the thermal recording medium of Example 1, a 10% aqueous solution of polyvinyl alcohol (trade name: PVA105, manufactured by Kuraray Co., Ltd.) was used instead of the 10% aqueous solution of polyoxyethylene sorbitan monostearate. A heat-sensitive recording material was obtained in the same manner as in Example 1 except for using the same.

The following evaluation tests were conducted on the thus obtained heat-sensitive recording medium, and the results are shown in Table 1.

[Recording Density and Sticking Resistance] Recording was performed with a thermal printer (trade name: UP-880, manufactured by Sony Corporation), and the recording density of the obtained recorded image was measured using a Macbeth densitometer (trade name: Model 914, Macbeth Corporation). Was measured in visual mode. In addition, the recording running performance was evaluated as follows by listening to the intensity of the sticking noise generated during recording. ：: Sticking sound is calm and slipperiness is good. ：: The sticking sound is quite quiet and the sliding property is quite good. Δ: The sticking sound was a little noisy and the sliding was a little bad. ×: The sticking noise was noisy and the slipperiness was poor.

[Resistant resistance] Thermal printer (trade name: U
(P-880, manufactured by Sony Corporation).
The state of the printing portion was visually determined as described below, and the recording travelability was examined. ：: There is no dripping in the printed portion and no pulling. ：: There is almost no bleeding in the printed portion, and there is almost no debris. Δ: There is a slight weeping in the printing part and a little dregs. X: There is a drool and a residue in the printing part.

[0042]

[Table 1]

[0043]

As is clear from the results shown in Table 1, the thermosensitive recording medium of the present invention has an excellent effect on the recording running property.

Claims (2)

[Claims] 1. A thermosensitive recording medium in which a recording layer containing a leuco dye and a colorant is provided on at least a support, wherein 0.001 containing a surfactant or a lubricant as a main component is provided on the recording layer.
Heat-sensitive recording material, characterized in that a top layer of to 0.1 g / m ^2. 2. The method according to claim 1, wherein a surfactant or a lubricant is added to the uppermost layer.
2. The heat-sensitive recording material according to claim 1, which contains 0% by weight or more.