JPH06247045A - Heat sensitive recording body - Google Patents

Abstract

PURPOSE:To provide a heat sensitive recording body which is superior in recording sensitivity, scarcely has adhesion of lees and is free from temperature fog. CONSTITUTION:In a heat sensitive recording body which is obtained by providing a recording layer containing colorless or light-colored basic dyes and color developing agent on a substrate, meta-terphenyl, or para-benzylbiphenyl and emulsion of stearic acid amide having a mean particle diameter of not exceeding 0.5mum are allowed to contain within the 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 which is excellent in recording sensitivity, has less dust deposits, and is free from thermal fogging.

[0002]

2. Description of the Related Art Heretofore, a heat-sensitive recording material has been well known which uses a heat energy of a heat-sensitive head or the like to develop a colorless or light-colored basic dye and a color developer. Since such a thermal recording material is relatively inexpensive and the recording equipment is compact and its maintenance is relatively easy, it is used not only as a recording medium for facsimiles and various computers but also in a wide range of fields such as thermal labels. .

In recent years, recording speeds of 10 seconds or less in A4 size for thermal fax and 120 characters / second or more for thermal printer have become possible, and there is a further demand for higher sensitivity of the thermal recording material. However, due to the increased sensitivity, the amount of adhered dust often increases, and the whiteness of the blank sheet often decreases during storage.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermosensitive recording medium which has little background fog due to the influence of temperature, humidity and the like, has very little dust adhesion, and has excellent recording sensitivity.

[0005]

SUMMARY OF THE INVENTION The present invention comprises:
A thermosensitive recording medium provided with a recording layer containing a colorless or light-colored basic dye and a color developer, wherein metaterphenyl or parabenzyl biphenyl and stearic acid amide having an average particle size of 0.5 μm or less are contained in the recording layer. It has been found that the above object can be achieved by incorporating the emulsion of the present invention, and the present invention has been completed.

[0006]

As described above, the present invention has a significant feature in that metaterphenyl or parabenzyl biphenyl is used as a sensitizer and an emulsion of stearic acid amide having an average particle size of 0.5 μm or less is used in combination. Is. In order to further enhance the recording sensitivity of the thermosensitive recording material using metaterphenyl or parabenzyl biphenyl, as a result of combining with various heat-fusible substances, an emulsion type stearic acid amide, particularly an average particle diameter of 0.5 μm or less When used in combination with a stearic acid amide emulsion, it was possible to achieve high sensitivity without causing dust adhesion or background fog. This is probably because the emulsified type has a sharper particle size distribution than the dispersed product obtained by mechanical dispersion, and there are almost no large particles such as 1 μm or more, and therefore exhibits extremely sharp melting behavior during heating printing. To be

In the present invention, the amount of the specific sensitizer used is not particularly limited, but generally 10 to 1000 parts by weight, preferably 50 to 500 parts by weight, relative to 100 parts by weight of the basic dye. It is desirable to adjust the range. The amount of the emulsifying type stearic acid amide used is not particularly limited, but is adjusted to 1 to 500 parts by weight, preferably 5 to 300 parts by weight, relative to 100 parts by weight of the specific sensitizer. It is desirable to do.

In the heat-sensitive recording material of the present invention, various known compounds can be used as the colorless or light-colored basic dye contained in the heat-sensitive recording layer, and examples thereof include the following.
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3- (4-diethylamino-2)
-Methylphenyl) -3- (4-dimethylaminophenyl) -6-dimethylaminophthalide, 3-diethylamino-7-dibenzylamino-benzo [a] fluorane,
3- (N-ethyl-Np-tolyl) amino-7-N-
Methylanilinofluorane, 3-diethylamino-7-
Anilinofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3,6-bis (diethylamino) fluorane-γ-anilinolactam, 3-cyclohexylamino-6-chlorofluorane, 3-diethylamino-6- Methyl-7-chlorofluorane, 3-diethylamino-7-chlorofluorane, 3- (N-ethyl-
N-isoamyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7 -Anilino Fluoran, 3
-Di (n-butyl) amino-6-methyl-7-anilinofluorane, 3-di (n-pentyl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-7
-(O-chlorophenylamino) fluorane, 3-di (n-butyl) amino-7- (o-chlorophenylamino) fluorane, 3-diethylamino-7- (o-fluorophenylamino) fluorane, 3-diethylamino-7- (M-Trifluoromethylanilino) fluorane, 3-di (n-butyl) amino-7- (o-fluorophenylamino) fluorane, 3- (N-ethyl-p-
Toluidino) -6-methyl-7-anilinofluorane,
3- (N-ethyl-p-toluidino) -6-methyl-7
-(P-Toluidino) fluorane, 3- (N-ethyl-)
N-furfurylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3- (N-methyl-Nn-propylamino) -6- Methyl-7-anilinofluorane, 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, 3,3-bis [1,1-bis (4 −
Pyrrolidinophenyl) ethylene-2-yl] -4,5,
6,7-Tetrabromophthalide, 3-p- (p-anilinoanilino) anilino-6-methyl-7-chlorofluorane, 2,2-bis {4- [6 '-(N-cyclohexyl-N-methyl Amino) -3'-methylspiro [phthalide-3,9'-xanthen-2'-ylamino] phenyl} propane, 3,6, -bis (dimethylamino) fluorene-9-spiro-3 '-(6'-dimethyl) amino)
Examples thereof include phthalide. Of course, it is not limited to these, and two or more kinds may be used in combination as required.

As the color developer which is contained in the recording layer and which is combined with the colorless or light-colored basic dye to form a color-developing system, various known developers can be used, and examples thereof include the following. Inorganic acid substances such as activated clay, attapulgite, colloidal silica, aluminum silicate, 4,4'-dihydroxydiphenyl sulfone, 4-cumylphenol, hydroquinone monobenzyl ether, 4,4'-isopropylidenediphenol, 1,1- Bis (4-hydroxyphenyl) cyclohexane, 4,4'-dihydroxydiphenyl-2,2-butane, 4,4'-dihydroxydiphenylmethane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2, 2-bis (4-
Hydroxyphenyl) heptane, bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, 1,1-
Bis (4-hydroxyphenyl) -1-phenylethane, 1,4-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- (4 '-Hydroxyphenyl) ethyl] benzene, 4,4'-dihydroxydiphenyl sulfide,
Di (4-hydroxy-3-methylphenyl) sulfine, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, bis (3-allyl -4-hydroxyphenyl) sulfone, 4-hydroxyphenyl-4'-benzyloxyphenyl sulfone, 4-hydroxy-3 ', 4'-tetramethylene biphenyl sulfone, 3,4-dihydroxyphenyl-p-tolyl sulfone, 4- Benzyl hydroxybenzoate, butyl bis (p-hydroxyphenyl) acetate, methyl bis (p-hydroxyphenyl) acetate, (4
-Hydroxyphenylthio) acetic acid-2- (4-hydroxyphenylthio) ethyl ester, di (p-hydroxyphenylthioethyl) ether, N, N'-di-m-chlorophenylthiourea, N- (phenoxyethyl)- Four
-Phenolic compounds such as hydroxyphenyl sulfonamide, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylic acid, p-chlorobenzoic acid, etc. Aromatic carboxylic acids, salts of these aromatic carboxylic acids with polyvalent metals such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel, and organic acid substances such as antipyrine complexes of zinc thiocyanate Etc. are illustrated. Of course, it is not limited to these, and two or more kinds may be used in combination as required.

In the heat-sensitive recording material of the present invention, the use ratio of the basic dye and the color developer contained in the recording layer is not particularly limited, but the basic dye 1 is generally used.
It is desirable to use about 10 to 1000 parts by weight, preferably about 50 to 500 parts by weight, of the developer with respect to 00 parts by weight.

The present invention is characterized in that a specific sensitizer is used, but it is also possible to use the following known sensitizers in combination within a range that does not impair the effects of the present invention. Is. Methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicosanoic acid amide, ethylenebistearic acid amide, behenic acid amide, methylenebisstearic acid amide, N-methylolstearic acid amide, dibenzyl terephthalate, terephthalate Acid dimethyl, dioctyl terephthalate, benzyl p-benzyloxybenzoate, 1-
Phenyl hydroxy-2-naphthoate, dibenzyl oxalate, oxalic acid-di-p-methylbenzyl, oxalic acid-
Di-p-chlorobenzyl, 2-naphthylbenzyl ether, tolubiphenyl 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-acetophene Examples include thizide, N-acetoacetyl-p-toluidine, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane and the like. The amount of these sensitizers used is not particularly limited, but it is generally desirable to adjust the amount within a range of about 5 to 500 parts by weight with respect to 100 parts by weight of the color developer.

Further, a preservative improving agent may be used in combination for the purpose of enhancing the preservability of the recorded image as long as the effect is not impaired. Specific examples of such storage improvers include 1,4-diglycidyloxybenzene, 4,
Epoxy compounds such as 4'-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4 '-(2-methyl-2,3-epoxypropyloxy) diphenyl sulfone, diglycidyl terephthalate, and bisphenol A type epoxy resin, 2,2 ′ -Methylenebis (4-methyl-6)
-Tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,
2'-ethylidene bis (4,6-di-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert
-Butylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-m-cresol), 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, 2,2-
Hindered phenol compounds such as bis (4-hydroxy-3,5-dimethylphenyl) propane, 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl] -4
-[Α ', α'-bis (4 "-hydroxyphenyl) ethyl] benzene, N, N'-di-2-naphthyl-p-phenylenediamine, 2,2'-methylenebis (4,6-
Di-tert-butylphenyl) sodium phosphate and the like can be mentioned.

To prepare a coating liquid for a recording layer containing these substances, water is generally used as a dispersion medium, and a basic dye, a color developer, and further a basic dye, a color developer, and a necessary amount are required by a stirring and crushing machine such as a ball mill, an attritor or a sand mill. A sensitizer or the like added according to the above is dispersed together or separately to prepare a coating liquid.
In the coating liquid, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, arabic gum as an adhesive,
Polyvinyl alcohol, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride copolymer salt,
The ethylene / acrylic acid copolymer salt, the styrene / acrylic acid copolymer salt, the styrene / butadiene copolymer emulsion, etc. are 10 to 40% by weight of the total solid content, preferably 15
It is used in an amount of about 30% by weight.

It is also possible to use various pigments in combination in the coating liquid, for example, kaolin, clay, calcium carbonate, calcined clay, calcined kaolin, titanium oxide, diatomaceous earth,
Inorganic pigments such as fine particulate anhydrous silica and activated clay, styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler, and organic pigments such as raw starch particles can be used.

Furthermore, various auxiliaries 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.

In the present invention, the method for 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 conventional technique, for example, air knife coating, varibar blade coating, pure blade coating. It can be formed by a method of coating and drying the coating liquid on the support by short dwell coating, curtain coating or the like. The coating amount of the coating liquid is also not particularly limited, and is usually ² to 12 g / m ² in dry weight, preferably 3 to 10 g.
The range is / m ² . As the support, paper, synthetic paper, plastic film or the like is appropriately selected and used.

In the present invention, it is possible to further improve the storability of a recorded image by providing a resin layer on the thermal recording material and / or on the back surface side thereof, if necessary.
Further, in the field of heat-sensitive recording material manufacturing, such as providing an undercoat layer on the support to improve image quality and sensitivity, processing the back surface of the recording material into an adhesive label by processing with an adhesive, and providing a magnetic layer on the back surface of the recording material. Various known techniques can be added. Further, the image quality and the image density can be improved by performing a super calendering process after forming the recording layer.

[0018]

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. In addition, "part" and "%" in an example show "weight part" and "weight%", respectively, unless there is particular notice.

Example 1 [Formation of Intermediate Layer] 40 parts of calcined clay (trade name: Ansilex, manufactured by EMC), 60% light calcium carbonate dispersion (trade name: Tamapearl TP-123CS, manufactured by Okutama Industry Co., Ltd.) 67 Parts, titanium oxide 20 parts, styrene-butadiene copolymer latex (solid content: 50%) 15 parts, polyvinyl alcohol 10% aqueous solution 30 parts, and water 170
The composition consisting of parts was mixed to prepare a coating liquid for the intermediate layer.
The obtained coating liquid was applied to a high-quality paper of 50 g / m ² and the dry weight was 13
An intermediate layer was formed by coating and drying so as to be g / m ² .

[Preparation of Solution A] 10 parts of 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 20 parts of metaterphenyl, 5 parts of a 5% aqueous solution of methylcellulose, and water. 40 parts of the composition was ground by a sand mill until the average particle size became 0.4 μm. [Preparation of solution B] 4,4'-isopropylidenediphenol 20 parts, 5% aqueous solution of methylcellulose 5 parts, and water 3
A composition consisting of 0 parts was pulverized with a horizontal sand mill until the average particle size became 0.5 μm.

[Formation of recording layer] A liquid 75 parts, B liquid 55
Part, stearic acid amide emulsion 21.5% liquid (trade name: High Micron G-270, manufactured by Chukyo Yushi Co., Ltd., average particle size 0.4 μm) 30 parts, 60% light calcium carbonate dispersion (trade name: Tamapearl TP -123CS, manufactured by Okutama Industry Co., Ltd.) 25 parts, 150 parts of a 10% aqueous solution of silicon-modified polyvinyl alcohol, 10 parts of a 30% aqueous dispersion of zinc stearate, and 60 parts of water are mixed and stirred to obtain a recording layer coating liquid. On the intermediate layer, the coating amount after drying is 4 g / m
After applying and drying using a varibar so as to be ² ,
Super calendering was performed to obtain a heat sensitive recording material.

Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that parabenzyl biphenyl was used in place of metaterphenyl in the preparation of solution A.

Comparative Example 1 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the 21.5% emulsion of stearic acid amide was not used in the formation of the recording layer.

Comparative Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 2 except that the 21.5% emulsion of stearamide was not used in the formation of the recording layer.

Comparative Example 3 [Preparation of Solution C] A composition consisting of 10 parts of stearic acid amide, 3 parts of a 5% aqueous solution of methylcellulose, and 32 parts of water was pulverized with a horizontal sand mill until the average particle size became 1.2 μm. [Formation of Recording Layer] In the formation of the recording layer, a thermosensitive recording medium was obtained in the same manner as in Example 1 except that 30 parts of C liquid was used instead of 30 parts of the 21.5% dispersion of stearic acid amide emulsion. It was

Comparative Example 4 Example 1 was repeated except that a stearic acid amide emulsion (average particle size 0.9 μm) was used in place of the stearic acid amide emulsion (average particle size 0.4 μm) in the formation of the recording layer. A thermosensitive recording medium was obtained in the same manner as described above.

Comparative Example 5 [Preparation of Solution D] From 10 parts of 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluorane, 5 parts of a 5% aqueous solution of methylcellulose, and 20 parts of water. The composition was pulverized with a sand mill until the average particle size became 0.4 μm.

[Formation of Recording Layer] Liquid D 35 parts, Liquid B 55
Part, stearic acid amide emulsion 21.5% liquid (trade name: High Micron G-270, manufactured by Chukyo Yushi Co., Ltd., average particle size 0.4 μm) 120 parts, 60% light calcium carbonate dispersion (trade name: Tamapearl TP -123CS, manufactured by Okutama Kogyo Co., Ltd.) 25 parts, 150 parts of a 10% aqueous solution of silicon-modified polyvinyl alcohol, 10 parts of a 30% aqueous dispersion of zinc stearate, and 30 parts of water. On the intermediate layer, the coating amount after drying is 4 g /
such that m ^2, coated with Bariba, dried to obtain a heat-sensitive recording material subjected to a super calendar treatment.

The seven types of heat-sensitive recording materials thus obtained were subjected to the following evaluation tests, and the results are shown in Table 1.

[Color density] Thermal recording medium evaluation machine [Product name:
TH-PMD, manufactured by Okura Electric Co., Ltd., and applied voltage 16
V, pulse cycle 0.51 ms, pulse width 0.40 m
Recording was performed under the condition of s, and the obtained recording density and the background fog on the white paper portion were measured in a visual mode with a Macbeth densitometer [RD-914 type, manufactured by Macbeth Co.].

[Evaluation of Debris Adhesion] Using a UF-32H high-speed fleximeter (manufactured by Matsushita Electric Transmission Co., Ltd.), a chart No. of the Institute of Image Electronics Engineers of Japan was used. 2 patterns, 20 ° C., 65% RH and 30
The head state after printing 100 m under each environment of ℃ and 80% RH is observed. ◯: Almost no dust adhesion is observed. Δ: A small amount of dust adhesion is observed, but there is no problem in practical use. ×: Printing trouble occurs due to a large amount of dust adhesion.

[0032]

[Table 1]

[0033]

As is clear from the results shown in Table 1, the thermosensitive recording medium of the present invention is a thermal recording medium which is excellent in recording sensitivity and has less dust deposits.

Claims (1)

[Claims] 1. A heat-sensitive recording material comprising a support and a recording layer containing a colorless or light-colored basic dye and a color developer, wherein the recording layer contains metaterphenyl or parabenzyl biphenyl and an average value. A heat-sensitive recording material containing an emulsion of stearic acid amide having a particle diameter of 0.5 μm or less.