JP2000006530A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the stability of coloring density, and render the preservative stability of an image part and nonimage part such as chemical resistance excellent by employing a phenol derivative and an anthranilic acid derivative each expressed by a specific formula as an electron acceptable compound. SOLUTION: The thermal recording material includes as an electron acceptable compound a phenol derivative expressed by formula I and an anthranilic acid derivative expressed by formula II. In the formula I, R1, R2 show a hydrogen atom, an alkyl group or a halogen atom respectively independently, and R3, R4 show a hydrogen atom, an alkyl atom, a halogen atom or a hydroxy group respectively independently. X shows an hydrogen atom, a hydroxy group or an alkyl group. As an alkyl groups expressed by R1, R2, R3, R4, X is preferably a 1-5C lower alkyl group. In the formula II, R5 is an arylcarbonyl group, an alkylcarbonyl group or an arylsulfonyl group. An addition quantity of such an anthranilic acid derivative is preferable to be 50-400 wt.% with respect to an electron donative achromatic dye.

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 having good color stability and excellent storage stability of a color image.

[0002]

2. Description of the Related Art Recording materials using an electron-donating colorless dye and an electron-accepting compound include pressure-sensitive paper, heat-sensitive paper, photosensitive pressure-sensitive paper,
It is already well known as a heat-sensitive recording paper and a thermal transfer paper. For example, British Patent No. 2,140,449, U.S. Patent Nos. 4,480,052, 4,436,920, JP-B-60-23992, JP-A-57-179636,
Nos. 60-123556 and 60-123557. In recent years, researches on the improvement of properties of recording materials such as (1) color density and color sensitivity (2) storage stability of non-image areas and image areas have been earnestly conducted. Conventionally, as an electron accepting compound for an electron donating colorless dye, bisphenol A, p-hydroxybenzoic acid esters, bis-
Various compounds such as (4-hydroxyphenyl) sulfones are known, but all of them are color density, color sensitivity, and storage stability of non-image areas (weather resistance, chemical resistance, plasticizer resistance).
Etc. had several disadvantages. For example, screw-
A heat-sensitive recording material using (4-hydroxyphenyl) sulfone or bis- (4-isopropoxyphenyl) sulfone had a problem that the background portion was fogged when writing with a fluorescent pen.

[0003] These thermal recording systems are applied to various fields such as facsimile machines, printers and labels, and their needs are increasing. However, the disadvantage that the heat-sensitive recording material causes fogging due to the solvent and the like, and the color forming body is oil and fat,
Due to the drawback of discoloration due to chemicals and the like, in the fields of labels, slips, word processing paper, plotter paper, and the like, the commercial value has been significantly impaired.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide high stability of color density and storage stability such as chemical resistance of an image area and a non-image area. It is intended to provide a heat-sensitive recording material having excellent properties.

[0005]

Means for Solving the Problems The present inventors have studied each of an electron-donating colorless dye and an electron-accepting compound, pursued the development of a good recording material and a recording material, and completed the present invention. did. That is, the heat-sensitive recording material of the present invention is a heat-sensitive recording material in which a heat-sensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound is provided on a support. And an anthranilic acid derivative represented by the following general formula (2).

[0006]

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(Wherein R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, or a halogen atom;
R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group,
Represents a halogen atom or a hydroxy group. X represents a hydrogen atom, a hydroxy group, or an alkyl group. )

[0008]

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Wherein R ⁵ is an arylcarbonyl group,
Represents an alkylcarbonyl group or an arylsulfonyl group. The thermosensitive coloring layer preferably contains a zinc compound, particularly zinc oxide, and a preferable electron donating colorless dye used in combination with the electron accepting compound is represented by the following general formula (3). Compounds to be used.

[0010]

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[0011] (represents wherein each R ^6, R ⁷ independently represent a hydrogen atom, an alkyl group or an aryl group, further R ⁶
And R ⁷ may combine with each other to form a ring. R ⁸ , R
⁹ independently represents a hydrogen atom, an alkyl group or an aryl group. R ¹⁰ represents a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group, or a halogen atom. )

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The heat-sensitive recording material of the present invention is characterized by containing a phenol derivative represented by the general formula (1) and an anthranilic acid derivative represented by the general formula (2) as electron-accepting compounds. Hereinafter, the phenol derivative and the anthranilic acid derivative will be described.

In the general formula (1), R¹, R^TwoEach
Independently a hydrogen atom, an alkyl group, or a halogen atom
And R^Three, R^FourAre each independently a hydrogen atom,
Represents a kill group, a halogen atom, or a hydroxy group. X
Represents a hydrogen atom, a hydroxy group, or an alkyl group.
R¹, R^Two, R^Three, R^Four, An alkyl group represented by X
For example, a lower alkyl group having 1 to 5 carbon atoms is preferable.
For example, methyl, ethyl, n-propyl, isopropyl
And a t-butyl group.
Also, R¹, R ^Two, R^Three, R^FourHalogen atom represented by
Include chlorine, bromine and iodine
However, among them, a chlorine atom and a bromine atom are preferable. This
Among these groups, R¹, R^Two, R^Three, R^Fouras,
A hydrogen atom and a methyl group are particularly preferred.
Hydrogen atoms are particularly preferred. Also, R¹, R^Two, R^Three, R
^FourMay be the same or different,
R¹, R^TwoAnd R^Three, R^FourIs preferably the same as
No.

In the general formula (2), R ⁵ represents an arylcarbonyl group, an alkylcarbonyl group or an arylsulfonyl group. R ⁵ is preferably an alkylcarbonyl group having 6 to 13 hydrogen atoms, an aryloxyalkylcarbonyl group having 7 to 9 carbon atoms,
An arylalkylcarbonyl group having 7 to 9 carbon atoms, an arylcarbonyl group optionally substituted with an alkyl group or alkoxy group having 6 to 9 carbon atoms, and arylsulfonyl optionally substituted with an alkyl group or alkoxy group Groups. Among these, an aryloxyacetyl group, a phenylacetyl group, an unsubstituted and methyl- or methoxy-substituted benzoyl group, or an unsubstituted and methyl-substituted benzenesulfonyl group are particularly preferred.

Hereinafter, specific examples of the phenol derivative represented by the general formula (1) and the anthranilic acid derivative represented by the general formula (2) are shown, but the present invention is not limited thereto. . [Phenol derivative represented by general formula (1)] 1) 2,4-bis (phenylsulfonyl) phenol 2) 2,4-bis (4-methylphenylsulfonyl)
Phenol 3) 2,4-bis (4-ethylphenylsulfonyl)
Phenol 4) 2,4-bis (4-isopropylphenylsulfonyl) phenol 5) 2,4-bis (2-methylphenylsulfonyl)
Phenol 6) 2,4-bis (4-chlorophenylsulfonyl)
Phenol 7) 2,4-bis (4-bromophenylsulfonyl)
Phenol 8) 2,4-bis (2,4-dimethylphenylsulfonyl) phenol 9) 2,4-bis (3,4-dimethylphenylsulfonyl) phenol 10) 2,4-bis (2,5-dimethylphenylsulfonyl) ) Phenol 11) 2,4-bis (phenylsulfonyl) -5-methylphenol 12) 2- (4-methylphenylsulfonyl) -4-
(Phenylsulfonyl) phenol 13) 2- (2,4-dimethylphenylsulfonyl)
4- (phenylsulfonyl) phenol 14) 2- (phenylsulfonyl) -4- (4-chlorophenylsulfonyl) phenol 15) 4,4′-dihydroxy-5- (phenylsulfonyl) diphenylsulfone 16) 2,4-bis (Phenylsulfonyl) resorcinol [anthranilic acid derivative represented by general formula (2)] 1) 2- (benzoylamino) benzoic acid 2) 2- (p-methylbenzoylamino) benzoic acid 3) 2- (p-methoxy) Benzoylamino) benzoic acid 4) 2- (p-ethylbenzoylamino) benzoic acid 5) 2- (p-ethoxybenzoylamino) benzoic acid 6) 2- (p-propylbenzoylamino) benzoic acid 7) 2- (m -Methylbenzoylamino) benzoic acid 8) 2- (o-methylbenzoylamino) benzoic acid 9) 2- (phenoxyacetylamino) benzoic acid 10) 2- (α-phenoxypropionylamino) benzoic acid 11) 2- (α-phenoxybutanoylamino) benzoic acid 12) 2- (phenylacetylamino) benzoic acid 13 ) 2- (Hexylcarbonylamino) benzoic acid 14) 2- (Heptylcarbonylamino) benzoic acid 15) 2- (Nonylcarbonylamino) benzoic acid 16) 2- (Undecylcarbonylamino) benzoic acid 17) 2- (Dodecyl) Carbonylamino) benzoic acid 18) 2- (phenylsulfonylamino) benzoic acid 19) 2- (p-methylphenylsulfonylamino)
Benzoic acid 20) 2- (m-methylphenylsulfonylamino)
Benzoic acid 21) 2- (o-methylphenylsulfonylamino)
Benzoic acid 22) 2- (p-chlorophenylsulfonylamino)
Benzoic acid 23) 2- (p-ethylphenylsulfonylamino)
Benzoic acid 24) 2- (p-methoxyphenylsulfonylamino) benzoic acid 25) 2- (p-ethoxyphenylsulfonylamino) benzoic acid 26) 2- (p-butoxyphenylsulfonylamino) benzoic acid 27) 2- (β -Naphthylsulfonylamino) benzoic acid

The filter represented by the general formula (1) according to the present invention.
Enol derivative and anthra represented by general formula (2)
One type of each of the nitric acid derivatives may be used.
More than one species may be used in combination. General formula according to the present invention
A phenol derivative represented by (1) and a phenol derivative represented by general formula (2):
The ratio of use with the anthranilic acid derivative represented is the weight ratio
And preferably in the range of 10:90 to 90:10
20:80 to 80:20 is more preferable, and even more preferable.
More preferably, it is in the range of 40:60 to 70:30. Pheno
Use of either a thiol derivative or an anthranilic acid derivative
When the use ratio is less than 10% by weight, fog is sufficiently prevented.
It is not possible to obtain excellent chemical resistance, so both are used together
The effect obtained by this becomes insufficient. Also, the general formula
The anthranilic acid derivatives represented by (2)
It is preferable to use them together.
In (2), R^FiveIs an arylcarbonyl group,
At least one anthranilic acid derivative which is a carbonyl group
And R ^FiveIs an arylsulfonyl group
It is preferable to use one or more derivatives together.

In the heat-sensitive recording material of the present invention, the amount of the phenol derivative represented by the general formula (1) and the anthranilic acid derivative represented by the general formula (2) to be added to the thermosensitive coloring layer depends on the electron donating property. 50-40 for colorless dye
0% by weight, preferably 100 to 300% by weight.
Is particularly preferred.

The thermosensitive coloring layer according to the present invention includes, in addition to the electron-accepting compound comprising the specific phenol derivative and the specific anthranilic acid derivative, other known electron-accepting compounds as long as the effects of the present invention are not impaired. Compounds can be used in combination. Known electron accepting compounds that can be used in combination include phenol derivatives, phenol resins, novolak resins, metal-treated novolak resins, metal complexes, salicylic acid derivatives, metal salts of aromatic carboxylic acids, acid clay,
Bentonite and the like. These examples are shown in
No. 0-9309, Japanese Patent Publication No. 45-14039,
2-140483, JP-A-48-51510, JP-A-57-210886, JP-A-58-87089,
JP-A-59-11286, JP-A-60-176799
JP-A-61-95988, JP-A-63-6597
9, JP-A-6-72984, JP-A-7-27809
No. 8, etc. When other electron-accepting compounds are used in combination, the total content of the electron-accepting compounds according to the present invention is at least 50%, especially 6%, of all the electron-accepting compounds.
It is preferable to use 0% or more.

As the electron-donating colorless dye that can be used in the present invention, conventionally known dyes can be used. Specifically, triphenylmethane phthalide compounds, fluoran compounds, phenothiazine compounds, indolyl phthalide compounds, leuco auramine compounds, rhodamine lactam compounds, triphenyl methane compounds, triazene compounds, spiropyrans And various compounds such as pyridine compounds, fluorene compounds, pyridine compounds and pyrazine compounds. Specific examples of the phthalides are described in U.S. Reissue Patent No. 23,024, U.S. Patent Nos. 3,491,111 and 3,491,112.
Nos. 3,491,116 and 3,509,
No. 174, specific examples of fluorans are disclosed in US Pat.
No. 4,107, No. 3,627,787, No. 3,6
No. 41,011, No. 3,462,828, No. 3,
Nos. 681,390, 3,920,510 and 3,959,571. Specific examples of spiropyrans are described in U.S. Pat. No. 3,971,808, and pyridine and pyrazine compounds are described in U.S. Pat. 3,775,424, 3,853,869 and 4,246,318, and specific examples of fluorene compounds are described in JP-A-63-94878. In the present invention, an electron-donating colorless dye represented by the following general formula (3) is particularly preferable.

[0020]

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In the formula, R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group or an aryl group, and R ⁶ and R ⁷ may be bonded to each other to form a ring. R ⁸ , R ⁹
Each independently represents a hydrogen atom, an alkyl group or an aryl group. R ¹⁰ represents a hydrogen atom, an alkyl group, an aryl group,
Represents an alkyloxy group or a halogen atom.

Here, R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰
May further have a substituent. R ⁶ , R
^7, the alkyl group represented by R ^8, R ⁹ or R ^10, preferably an alkyl group having 1 to 10 carbon atoms, which may have a substituent group, and a linear Even, even if cyclic, may have a branched chain, specifically, for example, methyl, ethyl, propyl, octyl,
Decyl, methoxyethyl, ethoxyethyl, methoxypropyl, methoxyethoxyethyl, ethoxycarbonylmethyl, 2-chloroethyl, 2- (1,3-dichloropropyl), isopropyl, 3-heptyl, cyclopentyl, methylcyclohexyl, cyclohexyl, cyclodecyl, adamantyl Benzyl, phenethyl and the like. The aryl group represented by R ⁶ , R ⁷ , R ⁸ , R ⁹ or R ¹⁰ has 6 to 6 carbon atoms which may have a substituent.
Preferred are 20 aryl groups, for example, phenyl, tolyl, chlorophenyl, 1-naphthyl, 2-naphthyl and the like.

The halogen atom represented by R ¹⁰ is preferably a chlorine atom or a bromine atom. The alkyl group represented by R ^10, preferably an alkyl group having 1 to 20 carbon atoms, such as methoxy, ethoxy, propyloxy, methoxy ethoxy, dodecyloxy, benzyloxy, and p-methoxybenzyloxycarbonyl and the like.

Preferred examples of these are 2-arylamino-3-H, halogen, alkyl or alkyloxy-6-substituted aminofluorans. As specific examples, for example, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6- (N
-Cyclohexyl-N-methylamino) fluoran, 2
-P-chloroanilino-3-methyl-6-dibutylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-anilino-3-methyl-6
(N-ethyl-N-isoamylamino) fluoran, 2
-Anilino-3-methyl-6- (N-ethyl-N-dodecylamino) fluoran, 2-anilino-3-methoxy-6-dibutylaminofluoran, 2-o-chloroanilino-6-dibutylaminofluoran, 2 -Anilino-
3-pentadecyl-6-diethylaminofluoran, 2
-Anilino-3-ethyl-6-dibutylaminofluoran, 2-o-toluidino-3-methyl-6-diisopropylaminofluoran, 2-anilino-3-methyl-6
-(N-isobutyl-N-ethylamino) fluoran,
2-anilino-3-methyl-6- (N-ethyl-N-tetrahydrofurfurylamino) fluoran, 2-anilino-3-chloro-6- (N-ethyl-N-isoamylamino) fluoran, 2-anilino- 3-methyl-6
(N-methyl-N-γ-ethoxypropylamino) fluoran, 2-anilino-3-methyl-6-N-ethyl-
N-γ-ethoxypropylaminofluoran, 2-anilino-3-methyl-6- (N-ethyl-N-γ-propoxypropylamino) fluoran, 2-anilino-3-
Methyl-6- (N-methyl-N-propylamino) fluoran and the like.

Particularly, 2-anilino-3-methyl-6-dialkylaminofluoran is preferred, and 2-anilino-
3-methyl-6-dibutylaminofluoran, 2-anilino-3-methyl-6- (N-ethyl-N-propylamino) fluoran, 2-anilino-3-methyl-6-dihexylaminofluoran, 2- Anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-
Methyl-6- (N-ethyl-N-isoamyl) aminofluoran and 2-anilino-3-methyl-6- (N-ethyl-N-isobutyl) aminofluoran are particularly preferred.

The thermosensitive coloring layer according to the present invention preferably contains a zinc compound from the viewpoint of image storability. Examples of the zinc compound that can be used in the present invention include zinc oxide,
Zinc hydroxide, zinc carbonate, zinc phosphate, zinc silicate and the like can be mentioned, and zinc oxide is particularly preferable. The amount of the zinc compound used is usually 10 to 4 with respect to the anthranilic acid derivative.
It is preferably 00% by weight, and more preferably 50 to 300% by weight. If the amount is less than 10% by weight, the effect of the addition is insufficient, and if the amount is more than 400% by weight, the effect is not improved, and the dispersion stability in the coating solution for the thermosensitive coloring layer is rather reduced. is there.

Further, the heat-sensitive coloring layer according to the present invention may contain a heat-fusible compound in order to improve the thermal response. Typical examples of the heat-fusible compound include aromatic ethers, thioethers, esters and / or thermoplastic substances such as aliphatic amides or ureides. Examples of these thermoplastics are described in JP-A-58-5 / 58.
No. 7989, No. 58-87094, No. 61-5878
No. 9, No. 62-109681, No. 62-132677
Nos. 63-151478 and 63-235961. The amount of the heat-fusible compound to be added is from 20% by weight to 30% with respect to the electron-accepting compound.
It is preferably 0% by weight, and particularly preferably in the range of 40% by weight to 150% by weight.

Next, a method for adjusting the thermosensitive coloring layer in the thermosensitive recording material of the present invention will be described. In the preparation of the thermosensitive coloring layer coating solution, the specific phenol derivative and anthranilic acid derivative, which are electron accepting compounds, are usually pulverized and dispersed in a dispersion medium to a particle size of 10 μm or less, preferably 3 μm or less. Used. In this adjustment, the compound represented by the general formula (1) and the compound represented by the general formula (2) may be separately mixed with each other in a dispersion, or may be simultaneously dispersed in the same dispersion medium. However, from the viewpoint of performance, those dispersed at the same time are preferable.

As described above, when a zinc compound is contained in the thermosensitive coloring layer, it is preferable to simultaneously disperse the zinc compound when dispersing the anthranilic acid derivative from the viewpoint of improving the performance. . Further, the heat fusible compound described below may be used alone dispersed,
It can also be used in the heat-sensitive coloring layer as a dispersion which is finely dispersed simultaneously with the electron-donating colorless dye or the electron-accepting compound.

As a dispersion medium used for preparing the coating solution for the thermosensitive coloring layer, an aqueous solution of a water-soluble polymer having a concentration of about 0.5 to 10% is generally used. Examples of the water-soluble polymer include polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, epichlorohydrin-modified polyamide, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic acid salicylic anhydride copolymer, Polyacrylic acid,
Examples thereof include polyacrylamide, methylol-modified polyacrylamide, starch derivatives, casein, and gelatin. Water is preferred as these solvents. If the concentration of the water-soluble polymer is too low, the viscosity of the dispersion medium decreases, and the dispersed particles tend to precipitate.If it is too high, the viscosity of the coating liquid increases, and uniform coating becomes difficult, resulting in poor handling properties. I do. Dispersion can be performed using a known dispersing device such as a ball mill, a sand mill, a horizontal sand mill, an attritor, a colloidal mill and the like.

Similarly, as the electron-donating colorless dye in the thermosensitive coloring layer coating solution, it is preferable to use a solid dispersion ground and dispersed in a dispersion medium to a particle size of 10 μm or less, preferably 3 μm or less. As the dispersion medium, those similar to those used for dispersing the electron-accepting compound can be used.

In order to further satisfy various requirements, known additives can be added to the thus-obtained thermosensitive coloring layer coating solution as long as the effects of the present invention are not impaired. . Examples of the additive include an inorganic pigment for preventing the recording head from being stained during recording, an oil-absorbing substance such as a polyurea filler, a fatty acid for improving the releasability from the head, and a metal soap. Therefore,
In general, an electron-donating colorless dye that is a color-forming component, an electron-donating compound, and the above-mentioned heat-fusible compound that is optionally added, a pigment, a metal soap, a wax, an antistatic agent, an ultraviolet absorber, an antifoaming agent, Additives such as a conductive agent, a fluorescent dye and a surfactant are appropriately mixed to prepare a thermosensitive coloring layer coating solution.

Hereinafter, additives that can be added to the thermosensitive coloring layer will be described. Pigments used as additives include kaolin, calcined kaolin, talc, fluorite, diatomaceous earth, calcium carbonate, aluminum hydroxide, magnesium hydroxide, zinc oxide, lithopone, amorphous silica, colloidal silica, calcined stone, Examples include silica, magnesium carbonate, titanium oxide, alumina, barium carbonate, barium sulfate, mica, microballoons, urea-formalin filler, polyester particles, and cellulose filler.

Examples of the metal soap include polyvalent metal salts of higher fatty acids, for example, zinc stearate, aluminum stearate, calcium stearate, zinc oleate and the like.

In the present invention, wax having a melting point of 40 to 120 ° C. may be used from the viewpoint of head matching with a facsimile. As the wax, a wax having a melting point of 40 to 120 ° C, preferably a paraffin wax, a polyethylene wax, a carnauba wax, a microcrystalline wax, a candy wax, a montan wax, or a fatty acid amide wax, particularly, a paraffin having a melting point of 50 to 100 ° C is preferred. Wax, montan wax and methylol stearamide are preferred. The amount of wax used is 5 to 2 of the electron donating colorless dye.
00% by weight, preferably 20 to 150% by weight.

As the hindered phenol compound, a phenol derivative in which at least one of the 2- or 6-position is substituted with a branched alkyl group is preferable. UV absorbers include cinnamic acid derivatives, benzophenone derivatives,
Benzotriazole phenol derivatives and the like, for example, butyl α-cyano-β-phenylcinnamate, o-benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t
-Butylphenol, o-benzotriazolyl-2,4
-Di-t-octylphenol and the like.

As the water-proofing agent, N-methylol urea,
N-methylolmelamine, water-soluble precondensates such as urea-formalin, glyoxal, dialdehyde compounds such as glutaraldehyde, boric acid, inorganic crosslinking agents such as borax,
Blend heat-treated products of polyacrylic acid, methyl vinyl ether-maleic acid copolymer, isobutylene-maleic anhydride copolymer and the like can be mentioned.

The obtained thermosensitive coloring layer coating solution may be used for paper supports such as woodfree paper, coated paper obtained by applying resin or pigment to paper, resin laminated paper, woodfree paper having an undercoat layer, synthetic paper, plastic film, etc. It is applied to a support to form a thermosensitive coloring layer. At this time, Jls-
Smoothness specified by 8119 is 500 seconds or more, especially 800
It is particularly preferable to use a smooth one for seconds or more from the viewpoint of dot reproducibility.

The coating amount of the electron-accepting compound according to the present invention is appropriately selected according to the desired characteristics of the heat-sensitive recording material, but is generally from 0.1 to 2.0 g / m ² , particularly preferably from 0.1 to 2.0 g / m ² . 0.
² to 1.5 g / m ² is preferred. The amount of the electron-donating colorless dye according to the present invention is not particularly limited, but is generally 0.05 to 1.0 g / m ² , particularly 0.1 to 1.0 g / m ² .
0.5 g / m ² is preferred.

The heat-sensitive recording material of the present invention is disclosed in JP-B-59-5.
3193, JP-A-59-197463, JP-A-62
It takes a form as described in the official gazette of −114989 or the like.

When an undercoat layer is provided on a support, an undercoat layer containing a pigment as a main component is preferable. As the pigment, any of general organic or inorganic pigments can be used. In particular, the oil absorption specified by JIS-K5101 is 40 cc /.
It is preferably 100 g or more, specifically, calcium carbonate, barium sulfate, titanium oxide, talc, wax, kaolin, calcined kaolin, aluminum hydroxide, amorphous silica, urea formalin resin powder, polyethylene resin powder and the like. No. When these pigments are applied to a support, the amount of the pigment is 2 g / m ² or more, preferably 4 g / m ² or more.
g / m ² or more.

As the binder used for the undercoat layer,
Examples thereof include a water-soluble polymer and a water-soluble binder, and these may be used alone or in combination of two or more. Water-soluble polymers include methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, starches, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, polyvinyl Alcohol, polyacrylamide and the like can be mentioned.

As the water-soluble binder, a synthetic rubber latex or a synthetic resin emulsion is generally used.
Examples include styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, and vinyl acetate emulsion. The amount of the binder used is 3 to 100% by weight, preferably 5 to 5% by weight, based on the pigment added to the undercoat layer.
0% by weight. Wax, decoloring inhibitor,
A surfactant or the like may be added.

In the heat-sensitive recording material of the present invention, a protective layer can be further formed on the heat-sensitive coloring layer. Two or more protective layers may be laminated as necessary. Materials used for the protective layer include polyvinyl alcohol, carboxy-modified polyvinyl alcohol, vinyl acetate-acrylamide copolymer, silicon-modified polyvinyl alcohol, starch, modified starch, methyl cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, gelatins, gum arabic, casein, Styrene-maleic acid copolymer hydrolyzate, styrene-maleic acid copolymer half-ester hydrolyzate, isobutylene-maleic anhydride copolymer hydrolyzate, polyacrylamide derivative, polyvinylpyrrolidone, polystyrene sodium sulfonate, sodium alginate Water-soluble polymers such as styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, methyl acrylate-butadiene rubber latex, acetic acid Water-insoluble polymer such as a sulfonyl emulsion is used.

In the protective layer, a pigment, a metal soap, a wax, a waterproofing agent, etc. may be added for the purpose of improving the matching property with the thermal head. Further, when applying the protective layer on the thermosensitive coloring layer, a surfactant may be added in order to obtain a uniform protective layer. As the surfactant, a sulfosuccinic acid-based alkali metal salt, a fluorine-containing surfactant, and the like are preferably used, and specifically, di- (n-hexyl) sulfosuccinic acid, di- (2-ethylhexyl) sulfosuccinic acid, and the like. Or an ammonium salt thereof is preferable, but an effect can be obtained with an anionic surfactant.

In the heat-sensitive recording material of the present invention, a coating solution similar to the protective layer is applied to the back surface to correct the curl balance of the support or to improve the chemical resistance from the back surface. A coat layer may be formed, and if desired, an adhesive may be applied to the back surface, and a release paper may be combined to form a label.

The heat-sensitive recording material of the present invention is excellent not only in the storage stability of the color image but also in the stability of the color image, especially the uniformity of the color density in environments with different humidity, and the uniformity of the color tone in images with different color densities. Excellent in scratch resistance and scratch resistance (rub fog when the surface is strongly rubbed with a nail or the like). Also,
As described above, in spite of having excellent performance, compared with a conventionally known heat-sensitive recording material having excellent image storability, the amount of expensive coloring material used can be reduced, and the cost is extremely low. Has features.

[0048]

【Example】

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to only the following Examples. Unless otherwise specified, “parts” and “%” in the examples indicate “parts by weight” and “% by weight”, respectively.

(Example 1) [Formation of thermosensitive coloring layer] (1) Preparation of solution A 3-dibutylamino-6-methyl-7-anilinofluoran 10 parts Polyvinyl alcohol 2.5% aqueous solution (Kuraray PVA- 105) 50 parts The above components were placed in a ball mill and dispersed day and night to obtain an electron-donating colorless dye solid dispersion (solution A) having a volume average particle diameter of 1.0 μm. (2) Preparation of B1 solution Electron-accepting compound of compound example 1 (compound of general formula (1)) 10 parts Polyvinyl alcohol 2.5% aqueous solution (Kuraray PVA-105) 50 parts The above components were placed in a ball mill and dispersed all day and night. And an electron-accepting compound solid dispersion having a volume average particle diameter of 1.0 μm (B
1 solution). (3) Preparation of B2 solution Electron-accepting compound of Compound Example 1 (compound of general formula (2)) 10 parts Zinc oxide 5 parts Polyvinyl alcohol 2.5% aqueous solution (Kuraray PVA-105) 50 parts And dispersed throughout the day and night, and an electron-accepting compound solid dispersion having a volume average particle diameter of 1.0 μm (B
Liquid 2). (4) Preparation of liquid C 20 parts 2-benzyloxynaphthalene 20 parts Polyvinyl alcohol 2.5% aqueous solution (Kuraray PVA-105) 100 parts The above components were placed in a ball mill and dispersed day and night, and heat having a volume average particle diameter of 1.0 μm was obtained. A fusible compound dispersion liquid (liquid C) was obtained. (5) Preparation of liquid D 40 parts of light calcium carbonate 1 part of sodium polyacrylate 60 parts of water The above components were dispersed using a sand mill to obtain a pigment dispersion liquid (liquid D) having a volume average particle diameter of 2.0 µm.

Each of the above dispersions, 60 parts of liquid A, and 60 parts of liquid B1
Parts, 65 parts of liquid B2, 120 parts of liquid C, 101 parts of liquid D, and 25 parts of a 21% zinc stearate dispersion were mixed to obtain a thermosensitive coloring layer coating liquid. The obtained thermosensitive coloring layer coating solution was provided with an undercoating layer mainly composed of a pigment and a binder.
coating amount in g / m ² undercoat base paper was coated dried bar coating so as to 5 g / m ^2, and calendered to obtain a heat-sensitive recording material of Example 1.

Example 2 The electron accepting compound (compound of the general formula (1)) of the compound example 1 in the solid dispersion (solution B1) of the electron accepting compound of the example 1 was replaced with the electron accepting compound of the compound example 2. A thermosensitive recording material of Example 2 was obtained in the same manner as in Example 1 except that the compound (the compound of the general formula (1)) was used. (Example 3) The electron accepting compound of the compound example 1 (compound of the general formula (2)) in the solid dispersion (solution B2) of the electron accepting compound of the example 1 was replaced with the electron accepting compound of the compound example 19 (the general formula (2)). A heat-sensitive recording material of Example 3 was obtained in the same manner as in Example 1 except that the compound (2) was used.

Example 4 Solution B1 was prepared according to the following formulation, and 10 parts of an electron accepting compound of Compound Example 1 (compound of general formula (1)) 2.5% aqueous solution of polyvinyl alcohol (Kuraray PVA-105) 50 parts of B2 solution was prepared by the following formulation, and the electron-accepting compound of Compound Example 1 (compound of general formula (2)) 5 parts The electron-accepting compound of Compound Example 19 (compound of general formula (2)) 5 Part Zinc oxide 5 parts Polyvinyl alcohol 2.5% aqueous solution (Kuraray PVA-105) 50 parts Heat-sensitive coloring layer coating liquid, A liquid 60 parts, B1 liquid 42 parts, B2
The heat-sensitive recording material of Example 4 was obtained in the same manner as in Example 1 except that 84.5 parts of the liquid, 120 parts of the liquid C, 101 parts of the liquid D, and 25 parts of a 21% zinc stearate dispersion were prepared. Was. (Example 5) The heat-sensitive recording material of Example 5 was prepared in the same manner as in Example 1 except that the zinc compound in the solid dispersion (B2 liquid) of the electron accepting compound of Example 1 was changed from zinc oxide to zinc carbonate. Obtained.

(Comparative Example 1) The B1 solution was prepared by the following formulation without using the B2 solution containing the electron accepting compound of the general formula (2), and the electron accepting compound of the compound example 1 (general formula (1 Compound)) 20 parts Polyvinyl alcohol 2.5% aqueous solution (Kuraray PVA-105) 100 parts The coating solution for the heat-sensitive coloring layer was prepared by mixing 60 parts of solution A, 120 parts of B1 solution, and C
120 parts of liquid, 101 parts of liquid D, 21% of zinc stearate
A thermosensitive recording material of Comparative Example 1 was obtained in the same manner as in Example 1, except that the adjustment was made by adding 25 parts of the dispersion liquid. (Comparative Example 2) B containing an electron-accepting compound of the general formula (1)
Solution 1 was not used, and solution B2 was prepared according to the following formulation. Electron-accepting compound of compound example 1 (compound of general formula (2)) 20 parts Zinc oxide 5 parts 2.5% aqueous solution of polyvinyl alcohol (Kuraray) PVA-105) 100 parts The coating solution for the heat-sensitive coloring layer was prepared by mixing 60 parts of solution A, 130 parts of solution B2, and C
120 parts of liquid, 101 parts of liquid D, 21% of zinc stearate
A thermosensitive recording material of Comparative Example 2 was obtained in the same manner as in Example 1 except that the adjustment was made by adding 25 parts of the dispersion liquid.

With respect to the heat-sensitive recording materials obtained in Examples 1 to 5 and Comparative Examples 1 and 2, items of sensitivity, fog, vinyl chloride resistance (PVC resistance), highlighter pen resistance, and ink jet sheet resistance were determined according to the following criteria. Table 1 shows the results of evaluating
Shown in

<Sensitivity> A thermal head (KJT-216-8MPD1) manufactured by Kyocera Corp.
Using a thermal printer having a pressure of 0 kg / cm ² , printing was performed with a pulse width of 2.1 ms using a pressure roll under the conditions of a head voltage of 24 V and a pulse period of 10 ms, and the print density was measured with a Macbeth reflection densitometer RD918. did. The higher the concentration, the better the sensitivity. <Fog> The background after being left in an environment of 60 ° C. for 24 hours was measured by Macbeth RD918. The lower the numerical value, the better the evaluation.

<PVC Resistance> A commercially available vinyl chloride sheet (polymer wrap) was brought into contact with a printing screen, and the residual concentration after standing at 25 ° C. for 24 hours was measured with a Macbeth RD918 to calculate the residual ratio. The higher the numerical value, the better the evaluation. <Highlighter resistance> Writing was performed with a highlighter (Zebra Highlighter 2-Pink), and the fog on the heat-sensitive recording material surface was visually evaluated. The criteria were as follows. ○ ・ ・ ・ ・ No fog is seen. Δ: Some fog is seen. ×: Fog is clearly seen. <Inkjet sheet resistance> Inkjet (EPS
ON MJ930C), the image printed with high quality and the surface of the heat-sensitive recording material were brought into contact with each other, and the residual ratio after standing at 25 ° C. for 48 hours was measured.

[0058]

[Table 1]

As is clear from the results shown in Table 1, the heat-sensitive recording materials obtained in Examples of the present invention have excellent color stability and sensitivity, and hardly cause fog even after forced storage. Further, it was found that the color image was excellent in PVC resistance, highlighter pen resistance, ink jet sheet resistance, etc., and among them, it was especially found that the ink jet sheet resistance was remarkably improved. Also, when the cost of the coating solution for the thermosensitive coloring layer was estimated, 4- (β-known as an electron accepting compound having excellent image storage stability equivalent to that of a conventional product, for example, the thermosensitive recording material of the present invention. Compared with a heat-sensitive recording material using (p-methoxyphenoxyethoxy) salicylic acid, the coating solution cost was 50% or less, which proved to be extremely economically advantageous.

According to the heat-sensitive recording material of the present invention, excellent effects such as high stability of coloring density and excellent storage stability such as chemical resistance of an image area and a non-image area can be achieved.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Iwakura 200 Onakazato, Fujinomiya City, Shizuoka Prefecture Fuji Photo Film F Co., Ltd. F term (reference) 2H026 AA07 BB14 BB15 BB25 DD19 DD23 DD32 DD53

Claims (4)

[Claims] 1. A thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound, wherein a phenol represented by the following general formula (1) is used as the electron-accepting compound. A thermosensitive recording material comprising a derivative and an anthranilic acid derivative represented by the following general formula (2). Embedded image (Wherein, R ¹ and R ² each independently represent a hydrogen atom, an alkyl group, or a halogen atom, and R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group, a halogen atom, or a hydroxy group. X represents a hydrogen atom, a hydroxy group, or an alkyl group.) (In the formula, R ⁵ represents an arylcarbonyl group, an alkylcarbonyl group, or an arylsulfonyl group.) 2. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive coloring layer contains a zinc compound. 3. The heat-sensitive recording material according to claim 2, wherein the zinc compound is zinc oxide. 4. The heat-sensitive recording material according to claim 1, wherein the electron-donating colorless dye contains a compound represented by the following general formula (3). Embedded image (Wherein, R ^6, R ⁷ each independently represent a hydrogen atom, an alkyl group or aryl group, further R ⁶ and R ⁷ may .R ⁸ also is bonded to each other to form a ring, R ⁹ are each Independently represents a hydrogen atom, an alkyl group or an aryl group.
R ¹⁰ represents a hydrogen atom, an alkyl group, an aryl group, an alkyloxy group or a halogen atom. )