JPH07266700A - Thermosensible recording paper - Google Patents

Abstract

PURPOSE:To provide a thermosensible recording paper for the second original drawing which has reduced substrate fogging and produces a recording image with good preservative property. CONSTITUTION:In thermosensible recording paper in which a thermosensible recording layer containing leuco dye and a coloration agent is laminated on a substrate paper sheet impregnated with a resin soluble in organic solvents, zirconium ammonium carbonate is incorporated into a resin solution of an organic solvent or an intermediate layer which is installed between the support and the thermosensible 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 paper for a second original drawing which utilizes the reaction between a leuco dye and a color developing agent.

[0002]

2. Description of the Related Art A heat-sensitive recording paper, which utilizes a color reaction between a colorless or light-colored leuco dye and a color-developing agent to react both color-forming substances with thermal energy from a thermal head to obtain a recorded image, is often used. Are known. Since such thermal recording paper is relatively inexpensive and the recording device is compact and its maintenance is easy, it is used not only as a recording medium for facsimiles and various computing devices but also in a wide range of fields. As such a field of use, there is an increasing demand for a thermal recording paper which can be used for a diazo second original drawing and a design drawing for a CAD or CAM system. There is a method of providing a heat-sensitive recording layer on a base paper impregnated with a heat-melted resin as a method of obtaining a heat-sensitive recording paper for the second original, but it has a low transparency and easily causes curling. There is. Further, a method of providing a heat-sensitive recording layer on a base paper impregnated with a resin dissolved in an organic solvent is described in JP-A-61-108581 and JP-B-57-16913, but the transparency is improved. However, there are problems such as occurrence of background fog and deterioration of recorded image with time.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat sensitive recording paper for a second original image, which has less background fog and is excellent in storability of a recorded image.

[0004]

Means for Solving the Problems The present inventor has proposed a heat-sensitive recording paper in which a heat-sensitive recording layer containing a leuco dye and a color former is provided on a base paper impregnated with a resin soluble in an organic solvent. It was found that the above problems can be effectively achieved by containing zirconium ammonium carbonate in a coating solution in which a resin is dissolved in a solvent or in an intermediate layer provided between a support and a thermosensitive recording layer. , Was completed.

[0005]

In the present invention, as the base paper impregnated with the resin soluble in the organic solvent, a high-quality paper having a basis weight of 30 to 120 g / m ² is used, but a highly viscous beaten chemical pulp is used as a raw material. It is preferable to use fine glassine paper of paper quality whose surface is smoothed by supercalendering because it has high transparency after resin impregnation.

In the present invention, a base paper is obtained by applying a coating solution prepared by dissolving a water-insoluble resin in an organic solvent on one or both sides of the base paper and drying the base paper. This is because when a water-based heat-sensitive paint is directly applied to the base paper, there are problems in production such as wrinkles and paper breaks, and when printed, the image quality deteriorates due to the wrinkles and fine line breaks occur. There is a problem such as occurrence, and it is a measure to solve this. Examples of such water-insoluble resins include acrylic acid ester copolymers such as methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate and 2-ethylhexyl methacrylate. Acrylic acid ester copolymer and methacrylic acid ester copolymer, vinyl acetate, urea resin, melamine resin, unsaturated polyester resin, epoxy resin, urethane resin, polyethylene terephthalate,
Existing materials such as ethylene-butynyl acetate copolymer, butyral resin, polyester resin, nitrocellulose, polystyrene, styrene-acrylic copolymer, styrene-methacrylic acid copolymer, and phenol resin are used as they are. Such a resin can be dissolved in a suitable organic solvent such as toluene, methyl ethyl ketone, or xylene to obtain a coating liquid.

Further, a pigment can be added to the resin coating liquid, and examples thereof include clay, deckite, nacrite, kaolin, aluminum hydroxide, magnesium hydroxide, calcium carbonate, calcined clay, amorphous silica, alumina,
Examples include calcined kaolin, barium sulfate, titanium oxide, pigments obtained by subjecting the surface of these pigments to beef tallow, and plastic pigments. Such a coating liquid is applied and dried by a suitable coating device such as a bar coater, a contra coater, a gravure coater, a curtain coater, a chanplex coater, a roll coater and a blade coater. The amount of coat to be applied and dried on the base paper is
0.1 to 10.0 g / m ² , preferably 0.3 to 5.0
It is applied in the range of g / m ² .

However, directly on the base paper impregnated with resin,
When the heat-sensitive recording layer is provided, there are problems such as occurrence of background fog and deterioration of the recorded image with time.
Alternatively, when zirconium ammonium carbonate is contained in the intermediate layer provided between the base paper and the heat-sensitive recording layer, background fog is generated and the deterioration of the recorded image with time is improved. The amount of ammonium zirconium carbonate contained in the resin coating liquid or the intermediate layer is 1 with respect to the total solid amount of the resin coating liquid.
.About.50% by weight, preferably 5 to 30% by weight, and 1 to 100% by weight, preferably 10 based on the total solid content of the intermediate layer.
It is desirable to adjust in the range of -80% by weight. In addition to ammonium zirconium carbonate, an aqueous adhesive such as polyvinyl alcohol, modified starch, or synthetic resin latex is used in the intermediate layer.

Various types of colorless or light-colored leuco dyes contained in the heat-sensitive recording layer are known, and the following are exemplified. 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-
Dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide, 3,3-bis (2-phenylindol-3-yl) -6-dimethylaminophthalide, 3- (p-dimethyl) Aminophenyl) -3-
A phthalide dye such as (1-methylpyrrol-3-yl) -6-dimethylaminophthalide and 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3
-Diethylamino-6-methylfluorane, 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-methyl-N-benzylamino)
Fluorane, 3-diethylamino-7-diethylaminofluorane, 3- (N-ethyl-p-toluidino) -6
-Methyl-7-phenylaminofluorane, 3- (N-
Ethyl-p-toluidino) -6-methyl-7- (p-toluidino) fluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 3-dimethylamino-6-methyl-7-phenylaminofluorane , 3-
Dibutylamino-6-methyl-7-phenylaminofluorane, 3-dipentylamino-6-methyl-7-phenylaminofluorane, 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- (N-ethyl-N-cyclopentylamino) -6-methyl-7-phenylaminofluorane, 3- [N- (3-ethoxypropyl)- N-methylamino] -6-methyl-7-phenylaminofluorane, 3- [N-ethyl-N- (3-ethoxypropyl) amino] -6-methyl-7-phenylaminofluorane, 3-diethylamino- 7- [m- (trifluoromethyl) phenylamino] fluorane, 3-diethylamino-7- (o-phenyl) Oro phenylamino) fluoran, 3- dibutylamino-7- (o-fluorophenylamino) fluoran, 3-diethylamino-6-chloro-7-phenyl-aminofluoran, 3- (N-ethyl--
Np-tolylamino) -7-methylfluorane, 3-
(N-ethyl-N-tetrahydrofurfurylamino)-
6-Methyl-7-anilinofluorane, 3- (N-cyclopentyl-N-ethylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-Np-tolylamino) -6 Fluorane dyes such as methyl-7-anilinofluorane, 3,6-bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethylamino)
Examples thereof include fluorene dyes such as phthalide. Of course, the dyes are not limited to these dyes, and two or more dyes may be used in combination.

As the color developer that develops the leuco dye in the heat-sensitive recording layer, various known color developers can be used in combination, and the following can be exemplified. 4,4'-dihydroxy-diphenylmethane, 4,4'-isopropylidene diphenol (bisphenol A), hydroquinone,
4,4'-cyclohexylidene bisphenol, 4,
4 '-[1,4-phenylenebis (1-methylethylidene)] bisphenol, 4,4'-[1,3-phenylenebis (1-methylethylidene)] bisphenol,
4,4 '-(1,3-dimethylbutylidene) bisphenol, 2,2-bis (4-hydroxyphenyl) -4-
Methyl-pentane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-thiobis (6-tert-butyl-3-methylphenol), 4,4'-dihydroxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxy-4'-methoxydiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 1,3 -Di [2- (4-hydroxyphenyl) -2-propyl] benzene, hydroquinone monobenzyl ether, methyl 4-hydroxybenzoate,
Ethyl 4-hydroxybenzoate, phenyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate, -p-chlorobenzyl 4-hydroxybenzoate, dimethyl 4-hydroxyphthalate, 1,5-bis (4-hydroxyphenylthio). ) -3-Oxa-pentane, (4-hydroxyphenylthio) acetic acid-2- (4-hydroxyphenylthio) ethyl ester, novolac type phenol resin,
Phenolic compounds such as phenolic polymers, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, 3,5-di-tert-butylsalicylic acid, 3-benzylsalicylic acid, 3- ( α-methylbenzyl) salicylic acid, 3-chloro-5- (α-methylbenzyl) salicylic acid, 3-phenyl-5- (α, α
-Dimethylbenzyl) salicylic acid, 3,5-di-α-methylbenzylsalicylic acid, 4- (2-P-methoxyphenoxyethoxy) salicylic acid, 4- (3-P-tolylsulfonylpropyloxy) salicylic acid and other aromatic carboxylic acids , And these phenolic compounds, organic acidic substances such as salts of aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel. Of course, these color developers may be used in combination of two or more if necessary.

In the present invention, a sensitizer may be used in combination depending on the purpose. Specific examples of the sensitizer include stearic acid amide, stearic acid methylenebisamide, oleic acid amide, palmitic acid amide, coconut fatty acid amide and other fatty acid amides, 1,2-di (3-methylphenoxy) ethane, 1 , 2-diphenoxyethane, 1
-Phenoxy-2- (4-methylphenoxy) ethane,
Parabenzyl biphenyl, naphthyl benzyl ether,
Benzyl-4-methylthiophenyl ether, 1-hydroxy-2-naphthoic acid phenyl ester, oxalic acid dibenzyl ester, oxalic acid-di-p-methylbenzyl ester, oxalic acid-di-p-chlorobenzyl ester, terephthalic acid dimethyl ester Examples thereof include esters, terephthalic acid dibutyl ester, terephthalic acid dibenzyl ester, isophthalic acid dibutyl ester, 1-hydroxynaphthoic acid phenyl ester, and various known heat-fusible substances. Among them, 1,2-di (3-methylphenoxy) ethane, 1,2-diphenoxyethane, 1-phenoxy-
2- (4-Methylphenoxy) ethane is particularly preferred.

The amount of the sensitizer used is not particularly limited, but it is generally desirable to adjust the amount within the range of 400 parts by weight or less relative to 100 parts by weight of the color developing agent. To prepare a coating liquid containing these substances, water is generally used as a dispersion medium, and a leuco dye is prepared by a stirrer / pulverizer such as a ball mill, attritor, or sand grinder, thiosalicylic acid as a storage stability improver, a developer and a sensitizer. Dispersed together with the agent or separately, it is prepared as a coating liquid. In such a coating liquid, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, arabic gum, polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride Polymer salts, ethylene / acrylic acid copolymer salts, styrene / acrylic copolymer salts, styrene / butadiene copolymer salt emulsions, etc. are 10-40% of the total solid content.
It is used in an amount of about 15 to 30% by weight, preferably about 15 to 30% by weight.

Further, various auxiliary agents can be added to the coating liquid, for example, sodium dioctylsulfosuccinate, sodium dodecylbenzenesulfonate, sodium lauryl alcohol sulfate / sodium salt, alginate, fatty acid metal salt and the like. Dispersant, benzophenone type,
Examples thereof include UV absorbers such as triazole type, defoaming agents, fluorescent dyes, and coloring dyes. If necessary, lubricants such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax and ester wax, kaolin, clay, talc, calcium carbonate, calcined clay, titanium oxide, diatomaceous earth, fine anhydrous silica and activated clay. It is also possible to add an inorganic pigment such as.

The method of forming the heat-sensitive recording layer is not particularly limited, and the heat-sensitive recording layer can be formed according to a conventionally well-known and commonly used technique, for example, air knife coating, varibar blade coating, pure blade coating, short dwell. It is formed by a method of applying and drying a coating liquid by coating or the like. The usual dry weight 2~12g / m ² there is no particular limitation on the coating amount of the coating liquid, preferably in the range of 3 to 10 g / m ^2. If necessary, a protective layer may be provided on the heat-sensitive recording layer and / or the back side of the heat-sensitive recording paper to further improve the storability of the recording / printing portion. In addition, various known techniques in the field of thermal recording paper production are added as necessary, such as providing an undercoat layer on the support to improve image quality and sensitivity, or applying adhesive treatment to the back surface of the recording material to process it into an adhesive label. I will get it. In the present invention,
If necessary, a super calender may be applied after coating the heat-sensitive recording layer to improve the image quality and the image density.

[0015]

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 represent parts by weight and% by weight, respectively.

Example 1 Preparation of solution A 10 parts of 3-dibutylamino-6-methyl-7-phenylaminofluorane, 15 parts of 1,2-di (3-methylphenoxy) ethane, 5% aqueous solution of methylcellulose 5
Part and 65 parts of water were pulverized with a sand mill until the average particle size became 1.0 μm, to obtain a liquid A.

Preparation of Solution B A composition comprising 35 parts of 4,4′-isopropyldiphenol, 5 parts of a 5% aqueous solution of methylcellulose, and 65 parts of water was pulverized with a sand mill until the average particle size became 1.6 μm, and B A liquid was obtained.

Preparation of base paper ^On a glassine paper having a basis weight of 50 g / m ² , 20 parts of a copolymer of styrene and methyl methacrylate (molecular weight, about 10,000) dissolved in 80 parts of toluene was applied to a coating solution after drying. Of 3 g / m ² was applied and dried to prepare a base paper impregnated with resin.

Formation of Intermediate Layer Ammonium zirconium carbonate 10 parts, silicon modified polyvinyl
A coating liquid consisting of 200 parts of a 10% aqueous solution of nyl alcohol
1.2g / m after coating on the above base paper ²Becomes
And then dried to form an intermediate layer.

Formation of Thermosensitive Recording Layer A coating consisting of 100 parts of solution A, 100 parts of solution B, 100 parts of a 10% aqueous solution of polyvinyl alcohol (trade name: PVA110, manufactured by Kuraray Co., Ltd.), 10 parts of light calcium carbonate, and 30 parts of water. The coating amount after drying the liquid on the above intermediate layer is 3.
It was coated and dried so as to be 1 g / m ² to form a heat-sensitive recording layer.

Formation of protective layer 60 parts of kaolin (trade name: UW-90, manufactured by EMC),
2 parts of 40% aqueous solution of sodium polyacrylate (trade name: Aron A-9, manufactured by Toagosei Kagaku), 30 parts of 30% aqueous dispersion of zinc stearate, polyvinyl alcohol (trade name: PVA117, manufactured by Kuraray Co., Ltd.) 10% aqueous solution 300
Parts and 100 parts of water were applied onto the thermosensitive recording layer so that the coating amount was 2.6 g / m ^2, and dried to form a protective layer. Further, it was subjected to a super calender treatment to obtain a heat sensitive recording paper.

Example 2 Preparation of base paper Basis weight 40 g / m²Zirconium carbonate
5 parts of aluminum, 100 parts of toluene, styrene and methacryl
20 parts of methyl acrylate copolymer (molecular weight, about 10,000)
The composition consisting of
The amount of cloth is 3g / m ²Coated and dried so that the resin does not
A dipped base paper was prepared.

Formation of Intermediate Layer, Thermosensitive Recording Layer, and Protective Layer 2 parts of 5% aqueous solution of sodium di (2-ethylhexyl) sulfosuccinate, 10 parts of silicon-modified polyvinyl alcohol
% Aqueous solution of 200 parts on the above base paper so that the coating amount after drying is 1.2 g / m ² and then dried.
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that the intermediate layer was formed.

Comparative Example 1 A thermosensitive recording paper was obtained in the same manner as in Example 1 except that zirconium ammonium carbonate was not used in the formation of the intermediate layer in Example 1.

Comparative Example 2 In the formation of the intermediate layer of Example 1, 40% of glyoxal was used instead of 10 parts of ammonium zirconium carbonate.
A thermosensitive recording paper was obtained in the same manner as in Example 1 except that 25 parts of the aqueous solution was used.

Comparative Example 3 The procedure of Example 1 was repeated except that the intermediate layer was not provided and the thermosensitive recording layer was formed on the base paper. A thermal recording paper was obtained in the same manner as in Example 1.

The heat-sensitive recording paper thus obtained was subjected to the following quality evaluation tests, and the results are shown in Table 1. "Recording density" Thermal recording evaluation machine (TH-P manufactured by Okura Electric Co., Ltd.
Recording was performed using an MD type and an applied energy of 0.4 mJ / dot), and the density of the obtained recorded image was measured by a Macbeth densitometer (Macbeth RD-100R type).

"Opacity" Measured in accordance with JIS P 8138.

"Preservation of recorded image" The thermal recording paper after recording with a thermal recording evaluation machine was left under the condition of 40 ° C-90% RH for 48 hours, and then the density of the recording area and the fog on the background area were measured by a Macbeth densitometer. It was measured at.

"Diazo Copy Suitability of Thermosensitive Recording Paper" Using a thermosensitive recording paper recorded by a thermal plotter (Roland LTX-120) as a master, a diazo copying machine (manufactured by Ricoh Co., Ltd., Recopy SUPER) was used as a master for the thermosensitive recording paper.
DRY 100 type) was used for copying, and the obtained copy image and the density of the background portion were measured with a Macbeth densitometer.

[0031]

[Table 1]

[0032]

As is clear from the results of Table 1, the heat-sensitive recording paper of the present invention is a heat-sensitive recording paper for the second original image which has less background fog and is excellent in storage stability of recorded images.

Claims (1)

[Claims] 1. A thermosensitive recording paper comprising a base paper impregnated with a resin soluble in an organic solvent and a thermosensitive recording layer containing a leuco dye and a coloring agent, wherein the resin is dissolved in the organic solvent. A heat-sensitive recording paper, characterized in that ammonium zirconium carbonate is contained in the applied coating solution or in an intermediate layer provided between the base paper and the heat-sensitive recording layer.