JP2000238433A - Heat-sensitive recording material and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress foaming in the case of dispersing a pigment contained in a protective layer, to improve dispersibility of the pigment and to obtain a good coating surface having no coating fault by incorporating at least one type selected from the group consisting of two compounds represented by two specific structural formulae in the protective layer. SOLUTION: At least one type selected from the group consisting of compounds represented by the formula I (wherein R is a 1-6C alkyl group) and the formula II (wherin R is 1-6C alkyl group, (a) and (b) are each an integer for satisfying (a)+(b)=30) is contained in a protective layer containing a pigment and a binder and formed on a heat-sensitive recording layer or an intermediate layer, and hence foaming generated in the case of dispersing the pigment can be effectively suppressed. In this case, an adding amount of the compound set to about 0.05 to 2 wt.% of an adding amount of the pigment contained in the protective layer is best. If the amount is excessively less, foaming suppressing effect and dispersibility improving effect might become insufficient.

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 a method for producing the same, and more particularly, to a high-quality heat-sensitive recording material suitable for medical recording media and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Thermosensitive recording methods include (1) no development is required, and (2) when the support is paper, the material is close to ordinary paper.
(3) easy handling, (4) high color density,
(5) the recording device is simple, reliable, and inexpensive;
(6) No noise at the time of recording, (7) Maintenance is unnecessary, etc., so that it has been developed in various fields in recent years. For example, fields such as facsimile and printer, labels such as POS, etc. Applications are expanding.

As the heat-sensitive recording material used for the heat-sensitive recording, those utilizing a reaction between an electron-donating colorless dye and an electron-accepting compound and those utilizing a reaction between a diazo compound and a coupler have been widely known. Have been.

Against this background, thermal heads have recently been used to cope with multicoloring, to project images and the like by an overhead projector, and to directly observe the images and the like on a light table. There is a demand for the development of a transparent heat-sensitive recording material which can be directly recorded on a recording medium.

Therefore, a substantially colorless color-forming component A and a substantially colorless color-forming component B which reacts with the color-forming component A to form a color are dispersed in a binder in fine particles, or A,
There has been proposed a heat-sensitive recording material produced by encapsulating either one of the microspheres B and providing a thermosensitive recording layer formed in the form of an emulsion on a transparent support such as a synthetic polymer film. ing.

[0006] Such a transparent thermosensitive recording material has good transparency itself, but has a problem that sticking and abnormal noise are liable to occur when printing with a thermal recording device such as a thermal printer. It has been proposed to provide a protective layer containing a pigment and a binder as main components on a heat-sensitive recording layer of a heat-sensitive recording material. The pigment is usually 1-2 μm
About m of the pigment is mixed with glass beads and the like, and dispersed until the particle diameter reaches a desired value. Then, the pigment is contained in the protective layer. In addition, bubbles generated due to air entrained in the liquid in the dispersion step are generated. Since the generation of bubbles prevents collision between the pigment and the glass beads, much time is required until the pigment has a desired particle size, and the productivity is reduced. Therefore, in order to remove bubbles generated at the time of dispersion out of the system and improve the speed of dispersing the pigment in a small size (hereinafter, referred to as “dispersibility”), a polyoxyethylene derivative-based antifoaming agent is used. Is used.

However, polyoxyethylene derivative-based antifoaming agents can improve the dispersibility, but have poor compatibility when mixed with a binder such as polyvinyl alcohol contained in the protective layer. There is a problem that cracks occur on the coating surface of the layer. This is considered to be because the polyoxyethylene portion weakens the adhesion of polyvinyl alcohol as a binder. As described above, at present, satisfactory thermosensitive recording materials having excellent coatability without coating defects and excellent manufacturability due to improved pigment dispersibility have not yet been obtained.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention suppresses the bubbling that occurs when the pigment contained in the protective layer is dispersed, improves the dispersibility of the pigment and increases the productivity, and has a good coated surface without coating defects. It is intended to provide a heat-sensitive recording material. Another object of the present invention is to provide a method for producing the above-described heat-sensitive recording material.

[0009]

Means for solving the above problems are as follows. That is, <1> in a heat-sensitive recording material having a heat-sensitive recording layer on a support and a protective layer containing at least a pigment and a binder on the heat-sensitive recording layer, the protective layer contains the following general formula (1) ) And at least one member selected from the group consisting of compounds represented by the following general formula (2).

[0010]

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(In the general formulas (1) and (2), R
Represents an alkyl group having 1 to 6 carbon atoms. General formula (2)
In the above, a and b represent integers satisfying a + b = 3 to 30. <2> The compound represented by the general formula (1) and the compound represented by the general formula (2) are 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,4
Ethylene oxide adduct of 7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,6-dimethyl-4-octyne-3 The heat-sensitive recording material according to <1>, which is an ethylene oxide adduct of 2,6-diol. <3> The above-mentioned <1> or <2>, wherein the pigment is an inorganic pigment surface-coated with at least one selected from the group consisting of higher fatty acids, metal salts of higher fatty acids, higher alcohols, and higher fatty acid amides. It is a heat-sensitive recording material of the description. <4> The sum of the amount of the compound represented by the general formula (1) and the amount of the compound represented by the general formula (2) is 0.1 to the amount of the pigment contained in the protective layer. 05-4
The heat-sensitive recording material according to any one of <1> to <3>, which is in terms of% by weight. <5> The thermosensitive recording material according to any one of <1> to <4>, wherein the pigment has a 50% volume average particle diameter by laser diffraction of 0.20 to 1.00 μm. <6> A step of applying a coating solution for forming a heat-sensitive recording layer on a support to form a heat-sensitive recording layer, and forming a protective layer by applying a coating solution for forming a protective layer containing at least a pigment and a binder. And these steps, in this order,
Or a method for simultaneously producing a thermosensitive recording material, wherein the pigment is at least one selected from the group consisting of a compound represented by the following general formula (1) or a compound represented by the following general formula (2) A method for producing a thermosensitive recording material, characterized by being dispersed in the coexistence.

[0012]

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(In the general formulas (1) and (2), R
Represents an alkyl group having 1 to 6 carbon atoms. General formula (2)
In the above, a and b represent integers satisfying a + b = 3 to 30. <7> The compound represented by the general formula (1) and the compound represented by the general formula (2) are selected from the group consisting of 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 2,4
Ethylene oxide adduct of 7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,6-dimethyl-4-octyne-3 The method for producing a thermosensitive recording material according to <6>, wherein the thermosensitive recording material is an ethylene oxide adduct of 2,6-diol. <8> The pigment according to <6> or <7>, wherein the pigment is an inorganic pigment surface-coated with at least one selected from the group consisting of higher fatty acids, metal salts of higher fatty acids, higher alcohols, and higher fatty acid amides. A method for producing the heat-sensitive recording material described above. <9> The sum of the amount of the compound represented by the general formula (1) and the amount of the compound represented by the general formula (2) is 0.1 to the amount of the pigment contained in the protective layer. 05-4
The method for producing a thermosensitive recording material according to any one of the items <6> to <8>, which is% by weight. <10> The method for producing a thermosensitive recording material according to any one of <6> to <9>, wherein the pigment is dispersed in a 50% volume average particle diameter of 0.20 to 1.00 μm by a laser diffraction method. is there.

In the present invention, when dispersing the pigment contained in the protective layer, a compound having at least an antifoaming action (hereinafter sometimes referred to as a “specific compound”) is used. It is possible to effectively suppress the occurrence of foaming at the time, to improve the dispersibility of the pigment and to improve the productivity as compared with the case where a conventional antifoaming agent is used. Further, unlike the conventional antifoaming agent, since it has good compatibility with a binder such as polyvinyl alcohol, a thermosensitive recording material having a good coated surface without coating defects can be obtained.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the heat-sensitive recording material of the present invention will be described in detail. [Thermal Recording Material] The thermal recording material of the present invention has a thermosensitive recording layer and a protective layer on a support in this order, and further has other layers as necessary.

(Protective Layer) The protective layer is formed on the heat-sensitive recording layer or, when the intermediate layer is provided as the other layer on the heat-sensitive recording layer.
The protective layer contains at least a pigment and a binder, and further includes the specific compound in order to effectively suppress foaming generated when the pigment is dispersed.
It contains at least one selected from the group consisting of a compound represented by the following general formula (1) and a compound represented by the following general formula (2).

[0017]

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The compound represented by the general formula (1) is a diol having an acetylene skeleton, and has at least a function as an antifoaming agent having an antifoaming action. On the other hand, the compound represented by the general formula (2) is obtained by adding ethylene oxide to a hydroxyl group of the compound represented by the general formula (1), and serves as an antifoaming agent having at least an antifoaming action. Has functions. In the general formulas (1) and (2), R represents an alkyl group having 1 to 6 carbon atoms. Specific examples of the R include, for example, an ethyl group, an iso-butyl group, a methyl group,
n-propyl group, iso-propyl group, n-butyl group,
Examples thereof include a t-butyl group, an n-pentyl group, and an iso-pentyl group. When the number of carbon atoms of the alkyl group represented by R exceeds 6, the water solubility is reduced, and it may be difficult to add the alkyl group to a water-based pigment dispersion. Also,
In the general formula (2), a and b represent integers satisfying a + b = 3 to 30. A + b is preferably 3 or more from the viewpoint of the balance between water solubility and defoaming property. On the other hand, a
When + b is more than 30, the defoaming property is reduced, and the purpose of improving the dispersibility may not be achieved. The specific compound used in the present invention may be used alone or in combination of two or more.

Among the compounds represented by the general formula (1), 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 3,6- Dimethyl-4-octyne-3,6-diol is particularly preferred.

[0020]

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In addition, among the compounds represented by the general formula (2), ethylene oxide addition of 2,4,7,9-tetramethyl-5-decyne-4,7-diol represented by the following structural formula: Body and 3,6-dimethyl-4-octyne-3,6
-Ethylene oxide adducts of diols are particularly preferred.

[0022]

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The specific compound used in the present invention is
It is preferably added when preparing a pigment dispersion by dispersing the pigment contained in the protective layer, but not only when dispersing the pigment, but also when preparing a coating solution for forming the protective layer. It may be added. The addition amount of the specific compound used in the present invention is preferably 0.05 to 4% by weight based on the addition amount of the pigment contained in the protective layer.
5 to 2% by weight is more preferred. If the amount is less than 0.05% by weight, the effect of suppressing foaming and the effect of improving dispersibility may be insufficient. On the other hand, when the addition amount exceeds 4% by weight, the foaming suppressing effect and the dispersibility improving effect are not further exhibited, and further, the specific compound itself forms micelles and the specific surface of the protective layer is coated with the specific compound. An overhang of the alkyl group in the compound may cause cissing which may be the cause.

The protective layer may have a single-layer structure or a laminated structure of two or more layers. Further, the pigment is usually used for the purpose of making recording by a thermal head suitable, that is, for the purpose of suppressing the occurrence of sticking, abnormal noise and the like, but it is preferable to use an organic and / or inorganic pigment.

The pigment used in the protective layer has an average particle size, more specifically, 50 particles measured by a laser diffraction method.
% Volume average particle size (Laser diffraction particle size distribution analyzer LA7
The average particle size of pigment particles corresponding to 50% volume in the pigment, measured by 00 (manufactured by Horiba, Ltd.). Hereinafter, it may be simply referred to as “average particle size”. ) Is 0.20
It is preferably 1.00 μm, and in particular, from the viewpoint of preventing the occurrence of sticking and abnormal noise between the head and the heat-sensitive recording material when recording with a thermal head, the above 50% volume average particle size is 0.1 μm. 20-0.50 μm
Is more preferably within the range. If the 50% volume average particle diameter exceeds 1.00 μm, the effect of reducing abrasion on the thermal head is small, which is not preferable.
The effect of preventing welding between the thermal head and the binder in the protective layer is reduced, and as a result, the thermal head and the protective layer of the heat-sensitive recording material are adhered to each other at the time of printing. .

As the pigment contained in the protective layer,
There is no particular limitation, and known organic and inorganic pigments can be mentioned. In particular, inorganic pigments such as calcium carbonate, titanium oxide, kaolin, aluminum hydroxide, amorphous silica and zinc oxide, and urea formalin Organic pigments such as resins and epoxy resins are preferred. Among them, kaolin,
Aluminum hydroxide and amorphous silica are more preferred. These pigments may be used alone or in combination of two or more. Among these, an inorganic pigment whose surface is coated with at least one selected from the group consisting of higher fatty acids, metal salts of higher fatty acids, higher alcohols and higher fatty acid amides is particularly preferable. Examples of the higher fatty acids include stearic acid, palmitic acid, myristic acid, and lauric acid.

These pigments are dispersed with the above-mentioned specific compound defined in the present invention and, for example, sodium hexametaphosphate, partially or completely saponified modified polyvinyl alcohol, polyacrylic acid copolymer, various surfactants and the like. Auxiliary agent, preferably partially saponified or completely saponified modified polyvinyl alcohol, in the presence of a polyacrylic acid copolymer ammonium salt, a known disperser such as a dissolver, a sand mill, a ball mill, etc., to the above-mentioned average particle size. It is preferable to use them dispersedly. That is, it is preferable that the pigment is used after being dispersed until the 50% volume average particle diameter of the pigment is in the range of 0.20 to 1.00 μm.

From the viewpoint of improving the transparency of the protective layer, the binder is preferably completely saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silica-modified polyvinyl alcohol, or the like. The specific compound used in the present invention has a good compatibility with a binder such as the polyvinyl alcohol and a good coated surface free from coating defects, compared to a conventionally used polyoxyethylene derivative-based antifoaming agent. Obtainable.

The protective layer may contain a known hardener, metal soap, or the like. In order to uniformly form the protective layer on the heat-sensitive recording layer or the intermediate layer, it is preferable to add a surfactant to the coating liquid for forming the protective layer. Examples of the surfactant include sulfosuccinic acid-based alkali metal salts and fluorine-containing surfactants. Specific examples thereof include di- (2-ethylhexyl) sulfosuccinic acid and di-sulfosuccinic acid.
Examples thereof include sodium salts or ammonium salts such as (n-hexyl) sulfosuccinic acid.

Further, wax is added to the protective layer for the purpose of reducing abrasion of the recording head, and a surfactant, metal oxide fine particles, inorganic electrolyte, polymer electrolyte and the like are added for the purpose of preventing electrification of the heat-sensitive recording material. Is also good.

The wax has a melting point of 40 to 10.
It is preferably in the range of 0 ° C. and the 50% volume average particle diameter is preferably 0.7 μm or less, more preferably 0.4 μm or less. The average particle size is 0.7
When the average particle size exceeds μm, the transparency of the protective layer is reduced, and image blurring occurs, which is not preferable. If the melting point is lower than 40 ° C., the surface of the protective layer becomes tacky, which is not preferable. If the melting point is higher than 100 ° C., sticking tends to occur, which is not preferable.

The wax having a melting point of 40 to 100 ° C. includes, for example, paraffin wax; petroleum wax such as microcrystalline wax; synthetic wax such as polyethylene wax; vegetable wax such as candelilla wax, carnauba wax and rice wax; Animal waxes such as lanolin; and mineral waxes such as montan wax. Among these, the melting point is 55-7.
Paraffin wax having a temperature of 5 ° C. is particularly preferred. The amount of the wax used is 0.5 to 40% by weight of the whole protective layer.
Is preferable, and 1 to 20% by weight is more preferable. Further, these waxes may be used in combination with a 12-hydroxystearic acid derivative, a higher fatty acid amide, or the like.

As a method of dispersing the wax to the above-mentioned 50% average particle diameter, a method of dispersing the wax in the presence of a suitable protective colloid or a surfactant by a known wet disperser such as a dyno mill or a sand mill. However, from the viewpoint of forming fine particles, after heating and melting the wax once, at a temperature equal to or higher than the melting point, high-speed stirring in a solvent in which the wax is insoluble or hardly soluble, means such as ultrasonic dispersion, etc. And a method in which the wax is dissolved in an appropriate solvent and then emulsified in a solvent in which the wax is insoluble or hardly soluble. At this time, an appropriate surfactant or protective colloid may be used in combination.

The dry coating amount of the protective layer is 0.2 to 7 g /
m ² is preferable, and 1 to 4 g / m ² is more preferable.

[Thermal Recording Layer] The thermosensitive recording layer contains at least a color-forming component and, if necessary, other components.

(Coloring component) The heat-sensitive recording layer may be of any composition as long as it has excellent transparency when not processed and has a property of being colored by heating. As such a heat-sensitive recording layer, a so-called two-component type heat-sensitive recording layer containing a substantially colorless color-forming component A and a substantially colorless color-forming component B that forms a color by reacting with the color-forming component A is used. However, the coloring component A or the coloring component B is preferably encapsulated in a microcapsule. Examples of the combination of the two components constituting the two-component type thermosensitive recording layer include the following (A) to (S).

(A) Combination of an electron-donating dye precursor and an electron-accepting compound. (A) Combination of a photodegradable diazo compound and a coupler. (C) organic metal salts such as silver behenate and silver stearate;
Combination with reducing agents such as protocatechinic acid, spiroindane and hydroquinone. (D) A combination of a long-chain aliphatic salt such as ferric stearate and ferric myristate and a phenol such as gallic acid and ammonium salicylate. (E) Organic acid heavy metal salts such as salts with nickel, cobalt, lead, copper, iron, mercury, silver and the like such as acetic acid, stearic acid, and palmitic acid, and calcium sulfide and strontium sulfide;
Combination with alkaline earth metal sulfides such as potassium sulfide,
Alternatively, a combination of the organic acid heavy metal salt and an organic chelating agent such as s-diphenylcarbazide and diphenylcarbazone. (F) Combination of (heavy) metal sulfates such as silver sulfide, lead sulfide, mercury sulfide, and sodium sulfide with sulfur compounds such as Na-tetrathionate, sodium thiosulfate, and thiourea. (G) an aliphatic ferric salt such as ferric stearate;
Combination with an aromatic polyhydroxy compound such as 4-dihydroxytetraphenylmethane. (H) organic noble metal salts such as silver oxalate and mercury oxalate;
Combination with organic polyhydroxy compounds such as polyhydroxy alcohol, glycerin and glycol. (Q) A combination of an aliphatic ferric salt such as ferric pelargonate and ferric laurate, and a thiocecilcarbamide or isothiocesylcarbamide derivative. (Co) A combination of a lead salt of an organic acid such as lead caproate, lead pelargonate or lead behenate with a thiourea derivative such as ethylenethiourea or N-dodecylthiourea. (Sa) A combination of a heavy metal salt of a higher fatty acid such as ferric stearate and copper stearate with zinc dialkyldithiocarbamate. (B) A substance that forms an oxazine dye such as a combination of resorcinol and a nitroso compound. (S) A combination of a formazan compound and a reducing agent and / or a metal salt.

Among them, in the heat-sensitive recording material of the present invention, (a) a combination of an electron-donating dye precursor and an electron-accepting compound, (a) a combination of a photodegradable diazo compound and a coupler, or ( C) It is preferable to use a combination of an organic metal salt and a reducing agent, and in particular, the above (A) or (A)
Is more preferable.

The heat-sensitive recording material of the present invention comprises a heat-sensitive recording layer having a haze value calculated from (diffuse transmittance / total light transmittance) × 100 (%), thereby reducing the haze value.
An image having excellent transparency can be obtained. The haze value is an index indicating the transparency of the material, and is generally calculated from the total light transmission amount, the diffuse transmission light amount, and the parallel transmission light amount using a haze meter. In the present invention, as a method of lowering the haze value, for example, the 50% volume average particle diameter of both the color forming components A and B contained in the heat-sensitive recording layer is set to 1.0 μm.
m or less, preferably 0.6 μm or less, and a method in which the binder is contained in the range of 30 to 60% by weight of the total solid content of the heat-sensitive recording layer. One of the color-forming components A and B is microencapsulated, For example, there is a method in which the other layer substantially forms a continuous layer after coating and drying, for example, a method of using an emulsion or the like. It is also effective to make the refractive index of the component used in the heat-sensitive recording layer as close to a certain value as possible.

Next, the combinations (A, B, C) of the above-mentioned compositions, which are preferably used for the heat-sensitive recording layer, will be described in detail below. First, (a) a combination of an electron-donating dye precursor and an electron-accepting compound will be described. The electron donor dye precursor preferably used in the present invention,
It is not particularly limited as long as it is substantially colorless, but has a property of donating electrons, or having a property of receiving a proton such as an acid to develop color,
It is preferably a colorless compound having a partial skeleton such as lactone, lactam, sultone, spiropyran, ester, amide and the like, and when these partial skeletons are contacted with an electron-accepting compound, these partial skeletons are opened or cleaved.

Examples of the electron-donating dye precursor include a triphenylmethanephthalide compound, a fluoran compound, a phenothiazine compound, an indolylphthalide compound, a leucouramine compound, a rhodamine lactam compound, and a triamine compound. Examples include phenylmethane-based compounds, triazene-based compounds, spiropyran-based compounds, fluorene-based compounds, pyridine-based compounds, and pyrazine-based compounds.

Specific examples of the phthalides include US Pat. No. Re. 23,024, US Pat. Nos. 3,491,111, 3,491,112, and 3,491. , 116, and 3,509,174. Specific examples of the fluorans are described in US Pat. No. 3,624,107.
No. 3,627,787, No. 3,641,01
No. 1, No. 3,462,828, No. 3,681,3
No. 90, No. 3,920,510, No. 3,959,
No. 571 and the like. Specific examples of the spiropyrans include US Pat.
71,808 and the like. Examples of the pyridine-based and pyrazine-based compounds include U.S. Patent Nos. 3,775,424 and 3,853,8.
No. 69, No. 4,246,318 and the like. Specific examples of the fluorene-based compound include compounds described in Japanese Patent Application No. 61-240989. Among these, black-colored 2-arylamino-3- [H, halogen, alkyl or alkoxy-6-substituted aminofluoran] is particularly preferable.

Specifically, for example, 2-anilino-3-
Methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-N-cyclohexyl-N-methylaminofluoran, 2-p-chloroanilino-3-methyl-6-dibutylaminofluoran, 2-anilino- 3-
Methyl-6-dioctylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-
Anilino-3-methyl-6-N-ethyl-N-isoamylaminofluoran, 2-anilino-3-methyl-6
N-ethyl-N-dodecylaminofluoran, 2-anilino-3-methoxy-6-dibutylaminofluoran,
2-o-chloroanilino-6-dibutylaminofluoran, 2-p-chloroanilino-3-ethyl-6-N-ethyl-N-isoamylaminofluoran, 2-o-chloroanilino-6-p-butylanilinofur Oran, 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-ethylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N
-Tetrahydrofurfurylaminofluoran, 2-anilino-3-chloro-6-N-ethyl-N-isoamylaminofluoran, 2-anilino-3-methyl-6-N-
Methyl-N-γ-ethoxypropylaminofluoran,
2-anilino-3-methyl-6-N-ethyl-N-γ-
Ethoxypropylaminofluoran, 2-anilino-3
-Methyl-6-N-ethyl-N- [gamma] -propoxypropylaminofluoran and the like.

Examples of the electron-accepting compound acting on the electron-donating dye precursor include acidic substances such as phenol compounds, organic acids or metal salts thereof, and oxybenzoic acid esters. And the compounds described in Japanese Patent Application Publication No. In particular,
2,2-bis (4'-hydroxyphenyl) propane (generic name: bisphenol A), 2,2-bis (4'-
Hydroxyphenyl) pentane, 2,2-bis (4′-
Hydroxy-3 ′, 5′-dichlorophenyl) propane, 1,1-bis (4′-hydroxyphenyl) cyclohexane, 2,2-bis (4′-hydroxyphenyl)
Hexane, 1,1-bis (4'-hydroxyphenyl)
Propane, 1,1-bis (4'-hydroxyphenyl)
Butane, 1,1-bis (4′-hydroxyphenyl) pentane, 1,1-bis (4′-hydroxyphenyl) hexane, 1,1-bis (4′-hydroxyphenyl) heptane, 1,1-bis ( 4'-hydroxyphenyl) octane, 1,1-bis (4'-hydroxyphenyl)-
2-methyl-pentane, 1,1-bis (4′-hydroxyphenyl) -2-ethyl-hexane, 1,1-bis (4′-hydroxyphenyl) dodecane, 1,4-bis (p-hydroxyphenylc) Mille) benzene, 1,3-
Bis (p-hydroxyphenylcumyl) benzene, bis (p-hydroxyphenyl) sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, bis (p
Bisphenols such as -hydroxyphenyl) acetic acid benzyl ester;

3,5-di-α-methylbenzylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-
α-α-dimethylbenzylsalicylic acid, 4- (β-p-
Salicylic acid derivatives such as methoxyphenoxyethoxy) salicylic acid;

Or a polyvalent metal salt thereof (particularly zinc and aluminum are preferred); benzyl ester of p-hydroxybenzoate, 2-ethylhexyl p-hydroxybenzoate, and 2- (2-phenoxyethyl) β-resorcinate Oxybenzoic acid esters such as esters; p-phenylphenol, 3,5-diphenylphenol, cumylphenol, 4-hydroxy-4′-isopropoxy-diphenylsulfone, 4-hydroxy-4′-phenoxy-diphenylsulfone, etc. Phenols. Among them, bisphenols are particularly preferable from the viewpoint of obtaining good color-forming properties. The above-mentioned electron accepting compounds may be used alone or in combination of two or more.

Next, (a) a combination of a photodegradable diazo compound and a coupler will be described. The photodegradable diazo compound is a compound that undergoes a coupling reaction with a coupler, which is a coupling component described below, to produce a desired hue, and is decomposed when receiving light in a specific wavelength range before the reaction, and is no longer coupled. It is a photo-degradable diazo compound that does not have a coloring ability even if a component is present. The hue in this color forming system is determined by the diazo dye formed by the reaction between the diazo compound and the coupler. Therefore, the color hue can be easily changed by changing the chemical structure of the diazo compound or the coupler, and depending on the combination,
Any color hue can be obtained.

The photo-decomposable diazo compound preferably used in the present invention includes an aromatic diazo compound, and specifically, an aromatic diazonium salt, a diazosulfonate compound, a diazoamino compound and the like. Examples of the aromatic diazonium salt include compounds represented by the following general formula, but are not limited thereto. The aromatic diazonium salt is preferably one having excellent light fixing property, little generation of colored stain after fixing, and a stable coloring part. Ar-N ₂ ⁺ X ^{-In the} above formula, Ar represents a substituted or unsubstituted aromatic hydrocarbon ring group, N ₂ ⁺ represents a diazonium group, X
^- represents an acid anion.

Many diazosulfonate compounds have been known in recent years, and are obtained by treating each diazonium salt with a sulfite, and can be suitably used in the heat-sensitive recording material of the present invention. .

The diazoamino compound can be obtained by coupling a diazo group with dicyandiamide, sarcosine, methyltaurine, N-ethylanthranic acid-5-sulfonic acid, monoethanolamine, diethanolamine, guanidine or the like. It can be suitably used for the heat-sensitive recording material of the present invention. Details of these diazo compounds are described in detail, for example, in JP-A-2-136286.

On the other hand, examples of the coupler that undergoes a coupling reaction with the above-mentioned diazo compound include, for example, 2-hydroxy-
In addition to 3-naphthoic anilide, resorcinol, and those described in JP-A-62-146678 and the like can be mentioned.

In the case where a combination of a diazo compound and a coupler is used in the heat-sensitive recording layer, the sensitization is carried out from the viewpoint that the coupling reaction can be further accelerated by performing the reaction in a basic atmosphere. A basic substance may be added as an agent. Examples of the basic substance include a water-insoluble or hardly soluble basic substance and a substance that generates an alkali by heating, for example, an inorganic or organic ammonium salt, an organic amine, an amide, urea or thiourea or a derivative thereof, Thiazoles, pyrroles, pyrimidines, piperazines, guanidines, indoles, imidazoles, imidazolines, triazoles, morpholines, piperidines, amidines,
Nitrogen-containing compounds such as forimazines or pyridines are exemplified. Specific examples of these are described in, for example,
No. 1,291,183, and the like.

Next, (c) a combination of an organic metal salt and a reducing agent will be described. Specific examples of the organic metal salt include silver salts of long-chain aliphatic carboxylic acids such as silver laurate, silver myristate, silver palmitate, silver stearate, silver arachiate or silver behenate; silver benzotriazole Silver salt of an organic compound having an imino group such as salt, silver benzimidazole, silver carbazole or silver phthalazinone; silver salt of a sulfur-containing compound such as s-alkylthioglycolate; fragrance such as silver benzoate and silver phthalate Silver salt of aromatic carboxylic acid; silver salt of sulfonic acid such as silver ethanesulfonate; o
Silver salts of sulfinic acids such as silver toluenesulfinate; silver salts of phosphoric acid such as silver phenylphosphate; silver barbiturates;
Examples include silver saccharinate, silver salt of salicyl asdoxime, or any mixture thereof. Of these, silver salts of long-chain aliphatic carboxylic acids are preferred, and silver behenate is more preferred. Also, behenic acid may be used together with silver behenate.

As the reducing agent, JP-A-53-102 can be used.
No. 0, page 227, lower left column, line 14 to page 229, upper right column, line 11 can be used as appropriate. Among them, mono, bis, tris or tetrakisphenols, mono or bisnaphthols, di or polyhydroxynaphthalenes, di or polyhydroxybenzenes,
Hydroxy monoethers, ascorbic acids, 3-pyrazolidones, pyrazolines, pyrazolones, reducing sugars, phenylenediamines, hydroxylamines, reductones, hydroxamic acids, hydrazides, amide oximes, N-hydroxyurea It is preferable to use a class or the like. Among the above, aromatic organic reducing agents such as polyphenols, sulfonamidophenols and naphthols are particularly preferred.

In order to ensure sufficient transparency of the heat-sensitive recording material, the heat-sensitive recording layer may contain (a) a combination of an electron-donating dye precursor and an electron-accepting compound, or (a) a photo-decomposable diazo compound. It is preferable to use a combination of and a coupler. In the present invention, it is preferable to use one of the color-forming component A and the color-forming component B after microencapsulation, and use the electron-donating dye precursor or the photodecomposable diazo compound after microencapsulation. Is more preferable.

(Microcapsules) The method for producing microcapsules will be described below in detail. The production of microcapsules includes an interfacial polymerization method, an internal polymerization method, an external polymerization method and the like, and any method can be adopted. As described above, the heat-sensitive recording material of the present invention is an electron-donating dye precursor,
Alternatively, it is preferable to microencapsulate the photodegradable diazo compound, particularly, an oil phase prepared by dissolving or dispersing the electron-donating dye precursor serving as the core of the capsule, or the photodegradable diazo compound in a hydrophobic organic solvent. Is mixed in an aqueous phase in which a water-soluble polymer is dissolved, and emulsified and dispersed by means of a homogenizer or the like, and then heated to cause a polymer formation reaction at the oil droplet interface, thereby forming a microcapsule wall of the polymer substance. Is preferably employed.

The reactant forming the polymer substance is added to the inside and / or outside of the oil droplet. Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer and the like. Among these, polyurethane, polyurea, polyamide, polyester,
Polycarbonates are preferred, and polyurethanes and polyureas are particularly preferred.

For example, when polyurea is used as a capsule wall material, polyisocyanates such as diisocyanate, triisocyanate, tetraisocyanate and polyisocyanate prepolymer, and polyamines such as diamine, triamine and tetraamine are used. The microcapsule wall can be easily formed by reacting the above prepolymer having an amino group, piperazine or a derivative thereof, or a polyol with the above-mentioned aqueous phase by an interfacial polymerization method.

Further, for example, a composite wall composed of polyurea and polyamide or a composite wall composed of polyurethane and polyamide is, for example, a polyisocyanate and a second substance which reacts therewith to form a capsule wall (for example, acid chloride or polyamine, Polyol) can be prepared by mixing a water-soluble polymer aqueous solution (aqueous phase) or an oil medium (oil phase) to be encapsulated, emulsifying and dispersing these, and then heating. Details of the method for producing the composite wall composed of polyurea and polyamide are described in JP-A-58-66948.

As the polyisocyanate compound,
A compound having a trifunctional or higher isocyanate group is preferred, but a bifunctional isocyanate compound may be used in combination. Specifically, diisocyanates such as xylene diisocyanate and its hydrogenated product, hexamethylene diisocyanate, tolylene diisocyanate and its hydrogenated product, and isophorone diisocyanate are used as main raw materials, and dimers of these dimers are used. Alternatively, in addition to a trimer (buret or isocyanurate), a polyfunctional adduct of a polyol such as trimethylolpropane and a bifunctional isocyanate such as xylylene diisocyanate, or a polyol such as trimethylolpropane and xylylene Examples thereof include a compound obtained by introducing a high molecular weight compound such as polyether having active hydrogen such as polyethylene oxide into an adduct with a bifunctional isocyanate such as range isocyanate, and a formalin condensate of benzene isocyanate. JP-A-62-2
Compounds described in JP-A-12190, JP-A-4-26189, JP-A-5-317694, and Japanese Patent Application No. 8-268721 are preferred.

The polyisocyanate is preferably added so that the microcapsules have an average particle size of 0.3 to 12 μm and the thickness of the capsule wall is 0.01 to 0.3 μm. The dispersed particle diameter is generally about 0.2 to 10 μm.

Specific examples of polyols and / or polyamines added to the aqueous phase and / or the oil phase as one of the constituents of the microcapsule wall by reacting with the polyisocyanate include propylene glycol, glycerin, and trimethylol. Examples include propane, triethanolamine, sorbitol, hexamethylenediamine and the like. When a polyol is added, a polyurethane wall is formed.
In the above reaction, it is preferable to keep the reaction temperature high or to add an appropriate polymerization catalyst from the viewpoint of increasing the reaction rate. The details of polyisocyanates, polyols, reaction catalysts, and polyamines for forming a part of the wall material are described in detail in Polygraphs (Polyurethane Handbook, edited by Keiji Iwata, Nikkan Kogyo Shimbun (1987)).

Further, a metal-containing dye, a charge controlling agent such as nigrosine, or any other optional substance can be added to the microcapsule wall as required. These additives can be included in the capsule wall at the time of wall formation or at any time. In addition, a monomer such as a vinyl monomer may be graft-polymerized in order to adjust the chargeability of the capsule wall surface as needed.

Furthermore, in order to make the microcapsule wall excellent in substance permeability even under a lower temperature condition and rich in color developability, it is preferable to use a plasticizer suitable for the polymer used as the wall material. The plasticizer preferably has a melting point of 50 ° C. or higher, and more preferably has a melting point of 120 ° C. or lower. Among them, those solid at room temperature can be suitably selected and used. For example, when the wall material is made of polyurea or polyurethane, a hydroxy compound,
Carbamate compounds, aromatic alkoxy compounds, organic sulfonamide compounds, aliphatic amide compounds,
Arylamide compounds and the like are preferably used.

In the preparation of the oil phase, the hydrophobic organic solvent used for dissolving the electron-donating dye precursor or the photo-decomposable diazo compound to form the core of the microcapsule has a boiling point of 100 to 300. Organic solvents at 0 ° C are preferred. Specifically, in addition to esters, dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene,
Dimethylbiphenyl, diisopropylbiphenyl, diisobutylbiphenyl, 1-methyl-1-dimethylphenyl-2-phenylmethane, 1-ethyl-1-dimethylphenyl-1-phenylmethane, 1-propyl-1-dimethylphenyl-1-phenylmethane , Triallylmethane (eg, tritolylmethane, toluyldiphenylmethane), terphenyl compound (eg, terphenyl), alkyl compound, alkylated diphenylether (eg, propyldiphenylether), hydrogenated terphenyl (eg, hexahydroterphenyl) , Diphenyl ether and the like. Among these, the use of esters is particularly preferred from the viewpoint of the emulsion stability of the emulsified dispersion.

Examples of the esters include phosphate esters such as triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate and cresyl phenyl phosphate;
Phthalates such as dibutyl phthalate, 2-ethylhexyl phthalate, ethyl phthalate, octyl phthalate, butyl benzyl phthalate; dioctyl tetrahydrophthalate; ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate; Benzoic acid esters such as benzyl benzoate; abietic acid esters such as ethyl abietic acid and benzyl abietic acid; dioctyl adipate; isodecyl succinate; dioctyl azelate;
Oxalic esters such as dibutyl oxalate and dipentyl oxalate; diethyl malonate; maleic esters such as dimethyl maleate, diethyl maleate and dibutyl maleate; tributyl citrate; methyl sorbate, ethyl sorbate, butyl sorbate and the like Sorbic acid esters; sebutylic acid esters such as dibutyl sebacate and dioctyl sebacate; monoesters and diesters of formic acid;
Butyric acid monoesters and diesters, lauric acid monoesters and diesters, palmitic acid monoesters and diesters, stearic acid monoesters and diesters,
Ethylene glycol esters such as oleic acid monoesters and diesters; triacetin; diethyl carbonate; diphenyl carbonate; ethylene carbonate; propylene carbonate; and boric esters such as tributyl borate and tripentyl borate.

Of these, the use of tricresyl phosphate alone or in combination is particularly preferred because the stability of the emulsion is the best. It is also possible to use the above oils together or in combination with other oils.

When the solubility of the electron-donating dye precursor or the photo-decomposable diazo compound to be encapsulated in the hydrophobic organic solvent is poor, a low-boiling solvent having high solubility is used in combination. Can also. Preferred examples of such a low-boiling solvent include ethyl acetate, isopropyl acetate, butyl acetate, and methylene chloride.

When the electron-donating dye precursor or the photo-decomposable diazo compound is used in the heat-sensitive recording layer of the heat-sensitive recording material, the content of the electron-donating dye precursor is 0.1 to 5.
Preferably ^{0g / m 2, 1.0~3.5g / m} 2 is more preferable. Further, the content of the photodegradable diazo compound,
0.02 to 5.0 g / m ² is preferable, and 0.10 to 4.0 g / m ² is more preferable from the viewpoint of color density.

When the content of the electron-donating dye precursor is 0.1%,
If the content of the photodegradable diazo compound is less than 1 g / m ² , or less than 0.02 g / m ² , a sufficient color density may not be obtained. If it exceeds 0.0 g / m ² , the transparency of the heat-sensitive recording layer may decrease.

On the other hand, an aqueous solution in which a water-soluble polymer is dissolved as a protective colloid is used as an aqueous phase to be used. After the oil phase is added to the aqueous solution, emulsification and dispersion are carried out by means of a homogenizer or the like. Serves as a dispersion medium for making the dispersion uniform and easy and for stabilizing the emulsified aqueous solution. Here, in order to more uniformly emulsify and disperse and stabilize, a surfactant may be added to at least one of the oil phase and the aqueous phase. As the surfactant, a well-known surfactant for emulsification can be used. The amount of the surfactant added was 0.1 to the weight of the oil phase.
-5% is preferable, and 0.5-2% is more preferable.

The surfactant to be contained in the aqueous phase is preferably selected from anionic or nonionic surfactants that do not cause precipitation or aggregation by acting on the protective colloid. it can. Preferred surfactants include, for example, sodium alkylbenzenesulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (eg, polyoxyethylene nonyl phenyl ether) and the like.

In the emulsification, the oil phase containing the above components and the aqueous phase containing the protective colloid and the surfactant are stirred at a high speed.
The emulsification can be easily carried out by using a means commonly used for emulsification of fine particles such as ultrasonic dispersion, for example, a known emulsifying apparatus such as a homogenizer, a Manton-Gawley, an ultrasonic disperser, a dissolver, and a Keddy mill. After the emulsification, the emulsion is preferably heated to 30 to 70 ° C. in order to promote the capsule wall forming reaction. During the reaction, in order to prevent aggregation of the capsules, it is preferable to reduce the probability of collision between the capsules by adding water or to perform sufficient stirring.

Further, a dispersion for preventing aggregation may be added again during the reaction. Generation of carbon dioxide gas is observed with the progress of the polymerization reaction, and the end of the generation can be regarded as an approximate end point of the capsule wall forming reaction. Usually, by reacting for several hours, the desired microcapsules can be obtained.

(Emulsified Dispersion) When the electron-donating dye precursor or the photo-decomposable diazo compound is encapsulated as a core substance, the electron-accepting compound or coupler to be used is:
For example, together with a water-soluble polymer and an organic base, other color-forming auxiliaries, etc., it can be used as a solid dispersion by means of a sand mill or the like, but after previously dissolved in a hardly water-soluble or insoluble high-boiling organic solvent, This is more preferably mixed with a polymer aqueous solution (aqueous phase) containing a surfactant and / or a water-soluble polymer as a protective colloid and emulsified with a homogenizer or the like and used as an emulsified dispersion. In this case, if necessary, a low boiling point solvent can be used as a dissolution aid. Further, the coupler and the organic base can be separately emulsified and dispersed, or can be mixed and then dissolved in a high boiling organic solvent to be emulsified and dispersed. Preferred emulsified dispersion particle size is 1 μm
It is as follows.

The high boiling organic solvent used in this case is
For example, it can be appropriately selected from the high boiling point oils described in JP-A-2-141279. Among them, the use of esters is preferred from the viewpoint of the emulsion stability of the emulsified dispersion, and tricresyl phosphate is particularly preferred. The above oils can be used together or with other oils.

The water-soluble polymer contained as the above protective colloid can be appropriately selected from among known anionic polymers, nonionic polymers and amphoteric polymers. A water-soluble polymer having a solubility in water of 5% or more is preferable. Specific examples thereof include polyvinyl alcohol or a modified product thereof, polyacrylamide or a derivative thereof, an ethylene-vinyl acetate copolymer, and a styrene-maleic anhydride copolymer. Coalesce, ethylene-maleic anhydride copolymer, isobutylene-maleic anhydride copolymer, polyvinylpyrrolidone, ethylene-acrylic acid copolymer, vinyl acetate-acrylic acid copolymer,
Examples include cellulose derivatives such as carboxymethylcellulose and methylcellulose, casein, gelatin, starch derivatives, gum arabic, sodium alginate and the like. Among these, polyvinyl alcohol, gelatin and cellulose derivatives are particularly preferred.

The mixing ratio of the oil phase to the aqueous phase (oil phase weight / water phase weight) is preferably from 0.02 to 0.6, and more preferably from 0.02 to 0.6.
1 to 0.4 is more preferable. When the mixing ratio is less than 0.02, the aqueous phase is too large to be diluted and lack production suitability. On the other hand, when the mixing ratio is greater than 0.6, the viscosity of the liquid increases, It is not preferable because inconvenient handling and a decrease in stability of the coating solution occur.

When an electron-accepting compound is used in the heat-sensitive recording material of the present invention, the amount of the electron-accepting compound is preferably 0.5 to 30 parts by weight, more preferably 1 to 30 parts by weight, based on 1 part by weight of the electron-donating dye precursor. 0.0 to 10 parts by weight is more preferable. When a coupler is used in the heat-sensitive recording material of the present invention, the amount of the coupler is preferably 0.1 to 30 parts by weight based on 1 part by weight of the diazo compound.

(Coating solution for heat-sensitive recording layer) The coating solution for heat-sensitive recording layer can be prepared, for example, by mixing the microcapsule solution prepared as described above with an emulsified dispersion. Here, the water-soluble polymer used as a protective colloid in the preparation of the microcapsule liquid, and the water-soluble polymer used as a protective colloid in the preparation of the emulsified dispersion, as a binder in the thermosensitive recording layer Function. Further, a coating solution for a heat-sensitive recording layer may be prepared by adding and mixing a binder separately from these protective colloids. As the binder to be added, a water-soluble binder is generally used, and polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, epichlorohydrin-modified polyamide, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer Coalescing,
Isobutylene-maleic salicylic anhydride copolymer, polyacrylic acid, polyacrylamide, methylol-modified polyacrylamide, starch derivatives, casein, gelatin and the like. Further, a water-proofing agent may be added to these binders for the purpose of imparting water resistance, or an emulsion of a hydrophobic polymer, specifically, a styrene-butadiene rubber latex, an acrylic resin emulsion, or the like may be added.

When applying the coating solution for a heat-sensitive recording layer onto a support, a known coating means used for a water-based or organic solvent-based coating solution is used. In order to uniformly coat and maintain the strength of the coating film, in the heat-sensitive recording material of the present invention, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starch, gelatin, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide, polystyrene or The copolymer, polyester or its copolymer, polyethylene or its copolymer, epoxy resin, acrylate resin or its copolymer, methacrylate resin or its copolymer, polyurethane resin, polyamide resin, polyvinyl butyral resin Using etc. It can be.

(Other components) Other components that can be used in the heat-sensitive recording layer are described below. The other components are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include known heat-fusible substances, ultraviolet absorbers, and antioxidants.

The heat-fusible substance can be contained in the heat-sensitive recording layer for the purpose of improving the thermal response. As the heat-fusible substance, aromatic ether, thioether,
Esters, aliphatic amides, ureides and the like. These examples are described in JP-A-58-57989 and JP-A-58-87.
Nos. 094, 61-58789, 62-10968
No. 1, 62-132677, 63-151478
No. 63-235961, JP-A-2-184489.
And JP-A-2-215585.

Examples of the ultraviolet absorber preferably include a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, a salicylic acid ultraviolet absorber, a cyanoacrylate ultraviolet absorber, and an oxalic acid anilide ultraviolet absorber. Can be These examples are disclosed in
Nos. 7-10537, 58-111942, 58-
No. 212844, No. 59-19945, No. 59-46
No. 646, No. 59-109055, No. 63-5354
No. 4, JP-B-36-10466, 42-26187
No. 48-30492, No. 48-31255, No. 48-41572, No. 48-54965, No. 50-
10726, U.S. Pat. No. 2,719,086
No. 3,707,375, No. 3,754,919
No. 4,220,711.

The antioxidant includes a hindered amine antioxidant, a hindered phenol antioxidant,
An aniline-based antioxidant and a quinoline-based antioxidant are preferably exemplified. These examples are disclosed in JP-A-59-15509.
No. 0, No. 60-107383, No. 60-107384
Nos. 61-137770 and 61-139481
And JP-A-61-160287.

The amount of the other components to be applied is set to 0.1.
About 0.5 to 1.0 g / m ² , preferably 0.1 to 0.4 g / m ^2.
g / m ² is more preferred. The other components are
It may be added inside the microcapsule or outside the microcapsule.

The heat-sensitive recording layer has an energy necessary for obtaining a saturated transmission density (D _T-max ) in order to suppress a density unevenness or the like caused by a slight difference in thermal conduction of a thermal head and to obtain a high-quality image. It is preferable that the thermosensitive recording layer has a wide range, that is, a wide dynamic range. The heat-sensitive recording material of the present invention has a heat-sensitive recording layer as described above, and has a thickness of 90 to 150 m.
J / mm ² range of thermal energy, transmission density D
It is preferable that the heat-sensitive recording layer has a property capable of obtaining _T 3.0.

The heat-sensitive recording layer is coated so that the dry coating amount after coating and drying is 1 to 25 g / m ² ;
It is preferable that the coating be performed so that the thickness of the layer is 1 to 25 μm.

[Support] In the heat-sensitive recording material of the present invention, a transparent support is preferably used in order to obtain a transparent heat-sensitive recording material. Examples of the transparent support include a synthetic polymer film such as a polyester film such as polyethylene terephthalate or polybutylene terephthalate, a cellulose triacetate film, or a polyolefin film such as polypropylene or polyethylene, and these may be used alone or in combination. be able to. The thickness of the synthetic polymer film is preferably 25 to 250 μm, and 50 to 250 μm.
200 μm is more preferred.

Further, the above-mentioned synthetic polymer film may be colored in an arbitrary hue. As a method of coloring a polymer film, a method of kneading a resin with a dye before forming a resin film to form a film, a coating solution in which the dye is dissolved in an appropriate solvent is prepared, and this is a colorless transparent resin A known coating method such as a gravure coating method, a roller coating method, a wire coating method, or the like, may be used on the film. Among them, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate in which a blue dye is kneaded is formed into a film, which is subjected to a heat treatment, a stretching treatment, and an antistatic treatment.

In particular, when the transparent heat-sensitive recording material of the present invention is observed from the side of the support on the sharksten, the sharksten light transmitted through the transparent non-image portion may cause an illusion, resulting in an unsightly image. In order to avoid this, as the transparent support, A (x = 0.2805, y = 0 on the chromaticity coordinates specified by the method described in JIS-Z8701)
0.3005), B (x = 0.2820, y = 0.29)
70), C (x = 0.2885, y = 0.315),
It is particularly preferable to use a synthetic polymer film colored blue in a square region formed by four points of D (x = 0.2870, y = 0.3040).

[Other Layers] The heat-sensitive recording material of the present invention comprises:
On the support, an intermediate layer, an undercoat layer, an ultraviolet filter layer, an antireflection layer, and the like can be provided as other layers.

(Intermediate Layer) The intermediate layer is preferably formed on the heat-sensitive recording layer. The intermediate layer is provided to prevent mixing of the layers and to block gases (such as oxygen) that are harmful to image storability. The binder used is not particularly limited, and polyvinyl alcohol, gelatin, polyvinylpyrrolidone, a cellulose derivative, or the like can be used depending on the system. In addition, various surfactants may be added to impart coating suitability. In order to further improve the gas barrier property, inorganic fine particles such as mica are added in an amount of 2 to 20% by weight, more preferably 5 to 10% by weight, based on the binder.
It may be added.

(Undercoat layer) In the heat-sensitive recording material of the present invention, in order to prevent the heat-sensitive recording layer from peeling off from the support, before the heat-sensitive recording layer containing microcapsules or the like or the anti-reflection layer is applied. In addition, an undercoat layer can be provided on the support. As the undercoat layer, an acrylate copolymer, polyvinylidene chloride, SBR, aqueous polyester, or the like can be used.
5 to 0.5 μm is preferred.

When the heat-sensitive recording layer is coated on the undercoat layer, the water contained in the heat-sensitive recording layer coating solution may swell the undercoat layer and deteriorate the image recorded on the heat-sensitive recording layer. Glutaraldehyde, 2,
It is preferable to harden using a dialdehyde such as 3-dihydroxy-1,4-dioxane and a hardening agent such as boric acid. The addition amount of these hardeners can be appropriately added in the range of 0.2 to 3.0% by weight depending on the weight of the undercoating material according to the desired degree of curing.

(Ultraviolet Filter Layer) An ultraviolet filter layer may be provided on the back side of the support opposite to the surface on which the heat-sensitive recording layer is applied, for the purpose of preventing image fading. The ultraviolet filter layer contains a benzotriazole-based, benzophenone-based, or hindered amine-based ultraviolet absorber.

(Anti-reflection layer) An anti-reflection layer containing fine particles having an average particle diameter of 1 to 20 μm, preferably 1 to 10 μm is provided on the back side of the support opposite to the surface on which the heat-sensitive recording layer is coated. Is also good. By applying this antireflection layer, the glossiness measured at an incident light angle of 20 ° is preferably 50% or less, more preferably 30% or less. Examples of the fine particles contained in the anti-reflection layer include fine particles such as starch obtained from barley, wheat, corn, rice, and beans, cellulose fiber, polystyrene resin, epoxy resin, polyurethane resin, urea formalin resin, poly ( (Meth) acrylate resin, polymethyl (meth) acrylate resin, copolymer resin such as vinyl chloride or vinyl acetate, fine particles of synthetic polymer such as polyolefin, calcium carbonate, titanium oxide, kaolin, smectite clay, aluminum hydroxide, silica, Examples include fine particles of inorganic substances such as zinc oxide. These may be used alone or in combination of two or more. Further, from the viewpoint of improving the transparency of the heat-sensitive recording material, the refractive index is 1.45.
It is preferably a fine particle substance having a particle size of from 1.75 to 1.75.

The heat-sensitive recording material of the present invention can be suitably manufactured by the method for manufacturing a heat-sensitive recording material of the present invention described below, but is not limited thereto, and is manufactured by another manufacturing method. You can also. The heat-sensitive recording material of the present invention suppresses bubbling generated when the pigment contained in the protective layer is dispersed, is excellent in manufacturability, and has a good coated surface without coating defects. It is suitably used in fields requiring high image quality such as media.

[Method of Manufacturing Thermosensitive Recording Material] A method of manufacturing the thermosensitive recording material of the present invention will be described below. The method for producing a heat-sensitive recording material of the present invention comprises a step of applying a heat-sensitive recording layer-forming coating solution on a support to form a heat-sensitive recording layer, and a coating solution for forming a protective layer containing at least a pigment and a binder. And a step of forming a protective layer by coating. These steps are performed in this order or at the same time, and further include other steps as necessary. To simultaneously perform the step of forming the heat-sensitive recording layer and the step of forming the protective layer, the heat-sensitive recording layer-forming coating liquid and the protective layer-forming coating liquid are simultaneously multi-layer coated on the support. Forming the thermal recording layer and the protective layer on the thermal recording layer at the same time.

In the method for producing a thermosensitive recording material of the present invention, the pigment comprises the compound represented by the general formula (1) or the compound represented by the general formula (2), which is the specific compound. It is characterized by being dispersed in the presence of at least one selected from the group. The method for dispersing the pigment includes dispersing the specific compound defined in the present invention, and, for example, sodium hexametaphosphate, partially or completely saponified modified polyvinyl alcohol, polyacrylic acid copolymer, various surfactants, and the like. Auxiliary agent, preferably partially saponified or completely saponified modified polyvinyl alcohol, polyacrylic acid copolymer In the coexistence of ammonium salt or the like, a known disperser such as a dissolver, a sand mill, a ball mill, or the like, until the desired particle size is reached. Spread. The amount of the specific compound added at this time is preferably from 0.05 to 4% by weight based on the above-mentioned amount of the compound, that is, the amount of the pigment contained in the protective layer.

As the support used here, the above-described support used for the heat-sensitive recording material of the present invention can be used. Further, as the heat-sensitive recording layer-forming coating liquid, the above-described heat-sensitive recording layer coating liquid can be used, and further, the protective layer-forming coating liquid is also used for the protective layer containing the pigment and the binder described above. A coating solution can be used. Examples of the other steps include a step of forming other layers such as the above-described intermediate layer and undercoat layer on a support. In the method for producing a heat-sensitive recording material of the present invention, in order to sequentially form an undercoat layer, a heat-sensitive recording layer, an intermediate layer, a protective layer, and the like on a support, a blade coating method, an air knife coating method, a gravure coating method, a roll coating method Known coating methods such as a coating method, a spray coating method, a dip coating method, and a bar coating method are used. According to the method for producing a heat-sensitive recording material of the present invention, the above-described heat-sensitive recording material of the present invention can be produced.

[0102]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

(Example 1) [Preparation of Coating Solution for Protective Layer] (Preparation of Pigment Dispersion for Protective Layer) Aluminum hydroxide treated with stearic acid as a pigment (trade name: Heidilite H42)
S, Showa Denko KK), 30 g, and 2,4,7,9-tetramethyl-5-decyne-
150 g of a 0.1% by weight aqueous solution of 4,7-diol (trade name: Surfynol 104, manufactured by Nissin Chemical Industry Co., Ltd.) was added (solid ratio to the pigment was 0.50% by weight), and the mixture was stirred for 3 hours. Dispersing aid (trade name: Poise 532A, manufactured by Kao Corporation) 0.2 g, 10% by weight aqueous solution of polyvinyl alcohol (trade name: PVA105, manufactured by Kuraray Co., Ltd.) 30
g, and 10 g of a 10% by weight aqueous solution of sodium dodecylbenzenesulfonate, and the mixture was dispersed by a sand mill.
A 30 μm protective layer pigment dispersion was obtained. The “average particle size” is obtained by dispersing a pigment to be used in the presence of a dispersing agent, diluting the pigment dispersion immediately after the dispersion to 0.5% by weight with water, and adding a test solution at 40 ° C. 75 ±
After adjusting the concentration to 1.0%, ultrasonic treatment was performed for 30 seconds, and a laser diffraction particle size distribution analyzer (trade name: LA70)
0, manufactured by Horiba, Ltd.)
The average particle size of the pigment particles corresponding to 0% volume is used, and the “average particle size” described below all represents the average particle size measured by the same method.

(Preparation of Wax Fine Particle Emulsion Dispersion) A polyoxyethylene stearyl ether surfactant (trade name: Kao Emulgen 320) was added to 20.0 g of solid paraffin wax having a melting point of 68 to 70 ° C. (manufactured by Kanto Scientific Co., Ltd.).
P, manufactured by Kao Corporation), and the mixture was heated to 75 ° C. and melted and mixed. This was added to 60 g of a 5% by weight aqueous solution of polyvinyl alcohol (trade name: PVA205C, manufactured by Kuraray Co., Ltd.) at 75 ° C., and the average particle size was 0.7 μm at 15,000 rpm using an ace homogenizer (manufactured by Nippon Seiki Co., Ltd.). The emulsification was performed so that During the emulsification, warm water at a temperature of 85 ° C. was flowed around the homogenizer so that the emulsification was always carried out at a temperature of 75 ° C. or higher to keep the temperature. After the emulsification was completed, 8.3 g of warm water was added, and then the liquid temperature was gradually lowered and cooled to room temperature to obtain a 30% by weight emulsified dispersion of wax fine particles.

(Preparation of Coating Solution for Protective Layer)
Wt% polyvinyl alcohol aqueous solution (trade name: PVA1)
90 g, 20.5 wt% zinc stearate dispersion (trade name: F155, manufactured by Chukyo Yushi Co., Ltd.) 0.5 g, 1.0 g boric acid aqueous solution 25 g, 30 wt% above 3.0 g of a wax fine particle emulsified dispersion, 150 g of the above-described pigment dispersion for a protective layer, 30 wt% aqueous silicone oil dispersion (trade name: SH490, manufactured by Dow Corning Toray Co., Ltd.) 5.0 g, 10 wt% dodecylbenzene 2.0 g of an aqueous solution of sodium sulfonate, the following structural formula (1)
15 g of a 2% by weight aqueous solution of the compound represented by

[0106]

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And a 40% by weight aqueous glyoxal solution
0 g was mixed to obtain a coating solution for a protective layer.

[Preparation of Coating Solution for Thermosensitive Recording Layer] Each of a microcapsule coating solution and a developer emulsified dispersion was prepared as follows. (Preparation of Microcapsule Coating Solution) As a coloring agent, 19 g of a compound represented by the following structural formula (2):

[0109]

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Compound 4.2 represented by the following structural formula (3)
g,

[0111]

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Compound 7.4 represented by the following structural formula (4)
g,

[0113]

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Compound 0.6 represented by the following structural formula (5)
g,

[0115]

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Compound 1.9 represented by the following structural formula (6)
g,

[0117]

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Compound 0.8 represented by the following structural formula (7)
g,

[0119]

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Was added to 36 g of ethyl acetate, heated and dissolved at 70 ° C., and then cooled to 35 ° C. 0.8 g of n-butanol and 26.4 g of capsule wall material (trade name: Takenate D127N, manufactured by Takeda Pharmaceutical Co., Ltd.) were added thereto, and the mixture was kept at 35 ° C. for 40 minutes.

This solution was prepared by adding an 8% by weight aqueous solution of polyvinyl alcohol (trade name: PVA217E, 26 g of water) to 26 g of water.
(Kuraray Co., Ltd.) was added to the aqueous phase mixed with 75 g,
Emulsification was performed for 5 minutes at 10,000 rpm using an ace homogenizer (manufactured by Nippon Seiki Co., Ltd.). After 140 g of water and 1.0 g of tetraethylenepentamine were further added to the obtained emulsion, an encapsulation reaction was performed at 60 ° C. for 3 hours to prepare a microcapsule coating liquid having an average particle diameter of 0.7 μm.

(Preparation of a developer emulsified dispersion) As a developer, 3.4 g of a compound represented by the following structural formula (8):

[0123]

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Compound 8.3 represented by the following structural formula (9)
g,

[0125]

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Compound represented by the following structural formula (10)
3g,

[0127]

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Compound represented by the following structural formula (11)
8g,

[0129]

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Compound represented by the following structural formula (12)
9g,

[0131]

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Compound represented by the following structural formula (13)
5g,

[0133]

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0.8 g of tricresyl phosphate,
15 g of ethyl acetate together with 0.4 g of diethyl maleate
And heated to 70 ° C. to dissolve. This solution is
5% by weight aqueous solution of polyvinyl alcohol (trade name: PV
A205C, manufactured by Kuraray Co., Ltd.) in an aqueous phase obtained by mixing 40 g of a 2.0% by weight aqueous sodium dodecylbenzenesulfonate solution 9 g and a 2% by weight aqueous solution of a compound represented by the following structural formula (14) 9.0 g. After adding

[0135]

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Ace homogenizer (Nippon Seiki Co., Ltd.)
At 10,000 rpm and an average particle size of 0.7
The emulsion was emulsified to a thickness of μm to obtain a developer emulsified dispersion.

(Preparation of coating solution for heat-sensitive recording layer) The coating solution for microcapsules (solid concentration 27% by weight) 14.2
g, the developer emulsified dispersion (solid content: 21% by weight) 8
5 g and 0.4 g of a 50% by weight aqueous solution of a compound represented by the following structural formula (15) were mixed to prepare a coating solution for a heat-sensitive recording layer.

[0138]

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[Preparation of Coating Solution for Intermediate Layer] 15% by weight aqueous gelatin solution (trade name: # 750GEL, manufactured by Nitta) 14
0 g, 3 g of 10 wt% sodium dodecylbenzenesulfonate as a surfactant, 7 g of 5 wt% sodium polystyrene sulfonate (molecular weight: 760,000, manufactured by Sankyo Chemical Co., Ltd.) for viscosity adjustment, and 21 g of a 2.5 wt% mica dispersion To 140
g of water to prepare a coating solution for an intermediate layer.

[Preparation of Coating Solution for Ultraviolet Filter Layer] (Preparation of Microcapsule Solution for Ultraviolet Filter Layer) 1.58 g of a compound represented by the following structural formula (16):

[0141]

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Compound represented by the following structural formula (17)
30 g,

[0143]

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Compound represented by the following structural formula (18)
20 g,

[0145]

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Compound represented by the following structural formula (19)
40g,

[0147]

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Compound represented by the following structural formula (20)
30 g,

[0149]

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Was added to 8.2 g of ethyl acetate, heated to 70 ° C. and dissolved, and then cooled to 35 ° C. To this, 0.9 g of capsule wall material (trade name: Takenate D110N, manufactured by Takeda Pharmaceutical Co., Ltd.) and 0.3 g of capsule wall material (trade name: Vernock D750, manufactured by Dainippon Ink Co., Ltd.) were added. The temperature was kept at 5 ° C for 5 minutes. This solution was treated with a 15% by weight aqueous solution of polyvinyl alcohol (trade name: PVA2).
05, manufactured by Kuraray Co., Ltd.) and an aqueous phase obtained by mixing 8.0 g of a 10% by weight aqueous solution of sodium dodecylbenzenesulfonate, and then using an ace homogenizer (manufactured by Nippon Seiki Co., Ltd.) to rotate at 15,000 rpm. For 15 minutes to obtain an emulsion having an average particle size of 0.25 μm. After further adding 60 g of water and 0.15 g of tetraethylenepentamine to the obtained emulsion, an encapsulation reaction was carried out at 40 ° C. for 3 hours to prepare a microcapsule solution for an ultraviolet filter layer having an average particle size of 0.25 μm. did.

(Preparation of UV Filter Layer Coating Solution) 10% by weight of silanol-modified polyvinyl alcohol (trade name: R2105, manufactured by Kuraray Co., Ltd.) in 42.31 g of water
The above microcapsule solution for a UV filter layer (solids concentration 24.2%) 1
3.5 g, and 17 g of a 50% by weight aqueous solution of the compound represented by the following structural formula (21)

[0152]

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Then, 65 g of 20% by weight colloidal silica (trade name: Snowtex O, Nissan Chemical Co., Ltd.) was mixed to prepare a coating solution for an ultraviolet filter layer.

[Preparation of Coating Solution for Antireflection Layer] 50 g of water
Rice starch with an average particle size of 5 μm (Matsuya Chemical Co., Ltd.)
0.1 g) and sufficiently dispersed, 2.5 g of a 2% by weight aqueous solution of di (2-ethyl) hexyl sulfosuccinate, 1.5 g of a 2% by weight aqueous solution of a compound represented by the following structural formula (22)

[0155]

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Then, 17 g of 20 wt% colloidal silica (trade name: Snowtex O, Nissan Chemical Co., Ltd.) was mixed to prepare a coating solution for an anti-reflection layer.

[Preparation of Transparent Support] The thickness is 175 μm, and the chromaticity coordinates specified by the method described in JIS-Z8701 are x = 0.2850, y = 0.299.
Blue polyethylene terephthalate (P
ET) On one side of the film, SBR latex was applied so that the dry coating amount was 0.3 g / m ² . On top of this, a 5% by weight gelatin aqueous solution (Nitta Gelatin # 810)
200 g, 5 wt% of a 2 μm particle size gelatin dispersion of polymethyl methacrylate resin particles (polymethyl methacrylate resin content 10 wt%) 0.5 g, 3 wt% 1,
1.0 g of 2-benzothiazolin-3-one aqueous solution and 2 g
A solution obtained by mixing 10 g of an aqueous solution of di (2-ethyl) hexyl sulfosuccinate in an amount of 0.1 g / m ^{2 by} weight is used.
It was applied so that The other side was coated in the same manner to form an undercoat layer on both sides of the support.

[Preparation of heat-sensitive recording material] The above-mentioned coating solution for an ultraviolet filter layer was applied to one surface of the support provided with the above-mentioned double-sided undercoat layer so that the dry coating amount was 1.8 g / m ^2. After drying, an ultraviolet filter layer was formed. Further, the coating liquid for an anti-reflection layer is applied on the ultraviolet filter layer so that a dry coating amount is 2.2 g / m ² .
After drying, an anti-reflection layer was formed on the ultraviolet filter layer.

Next, on the surface of the support opposite to the surface on which the ultraviolet filter layer and the anti-reflection layer were provided, the above-mentioned coating solution for the heat-sensitive recording layer was dried and applied in an amount of 16.5 g / m ² . And dried to form a heat-sensitive recording layer. The heat-sensitive recording layer, the intermediate layer coating liquid, and the protective layer coating solution successively, dry coating amount applied so that the 1.0 g / m ^2, and 2.5 g / m ² respectively, dry Thus, an intermediate layer and a protective layer were formed to obtain a transparent thermosensitive recording material of the present invention.

<Evaluation of Film Strength> The obtained heat-sensitive recording material was applied to a thermal head (trade name: KGT, 260-12M).
PH8, manufactured by Kyocera Corporation) with a head pressure of 10 kg /
cm ^2, after recording at recording energy 120 mJ / mm ^2, to evaluate the presence or absence of the coating film surface defects visually. Table 1 shows the results.

<Evaluation of Dispersibility of Pigment> The 2,4,7,9-tetramethyl-5-decyne-4,7-diol (trade name: Surfy) used in the preparation of the pigment dispersion for the protective layer was used. In order to evaluate the dispersibility of the pigment due to the addition of NOL 104 (manufactured by Nissin Chemical Industry Co., Ltd.), the time (h) required for dispersing 1000 kg of the pigment to an average particle size of 0.30 μm was measured. The average particle size of the pigment before dispersion was 1.2 μm. That is, stearic acid-treated aluminum hydroxide (trade name: Heidilite H42S, manufactured by Showa Denko KK) 100
0 kg and 2,4,7,9-tetramethyl-5-decyne-4,7-diol (trade name: Surfynol 10
4, Nisshin Chemical Industries, Ltd.)
kg (solids ratio to the pigment is 0.50% by weight).
After stirring for an hour, a predetermined amount of the above-mentioned dispersing aid was added thereto, and the mixture was dispersed with a sand mill at a flow rate of 10 kg / min.
The time (h) required to obtain a 0 μm protective layer pigment dispersion was measured. Table 1 shows the results.

<Evaluation of defoaming action> The 2,4,7,9-tetramethyl-5-decyne-4,7-diol (trade name: Surfynol) used in the preparation of the pigment dispersion for the protective layer was used. 104, manufactured by Nissin Chemical Industry Co., Ltd.) in order to evaluate the defoaming effect by adding the protective layer coating solution under a certain condition, then put 50 ml into a glass cylinder having an inner diameter of 50 mm, and from a height of 90 cm. 200 ml of the coating solution was dropped over 30 seconds, and the height of the foam from the liquid level 30 minutes after the completion of dropping was measured. Table 1 shows the results.

(Example 2) In Example 1, 2,4,7,9-tetramethyl-5-decyne-4,7-diol used in the preparation of the pigment dispersion for the protective layer was replaced with 2,2 4,
Ethylene oxide adduct of 7,9-tetramethyl-5-decyne-4,7-diol (addition rate: 3.5 mol) (trade name:
(Surfinol 440, manufactured by Nissin Chemical Industry Co., Ltd.), except that a heat-sensitive recording material was prepared in the same manner as in Example 1.
The film strength was evaluated in the same manner as described above. The above 2, 4,
Evaluation of dispersibility of pigment and defoaming action in the same manner as in Example 1 using an ethylene oxide adduct of 7,9-tetramethyl-5-decyne-4,7-diol (addition rate: 3.5 mol) Was evaluated. Table 1 shows the results.

Comparative Example 1 In Example 1, 2,4,7,9-tetramethyl-5-decyne-4,7-diol used in preparing the pigment dispersion for the protective layer was completely added. Other than that, a thermosensitive recording material was prepared in the same manner as in Example 1, and the film strength was evaluated in the same manner as in Example 1. Also,
2,4,7,9-tetramethyl-5-decyne-4,7-
The evaluation of the dispersibility of the pigment and the evaluation of the defoaming action were performed in the same manner as in Example 1 without adding any diol. Table 1 shows the results.

Comparative Example 2 In Example 1, 2,4,7,9-tetramethyl-5-decyne-4,7-diol used in the preparation of the pigment dispersion for the protective layer was replaced with polyoxy Block copolymer of polyoxyethylene which is an ethylene derivative-based defoaming agent (trade name: Newpol PE-68,
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that Sanyo Chemical Co., Ltd.) was used, and the film strength was evaluated in the same manner as in Example 1. Further, the dispersibility of the pigment and the evaluation of the defoaming effect were evaluated in the same manner as in Example 1 using the above-mentioned polyoxyethylene derivative-based antifoaming agent. Table 1 shows the results.

[0166]

[Table 1]

From the results shown in Table 1, since Examples 1 and 2 use the specific compounds specified in the present invention, the pigments are more desirable than Comparative Example 1 in which no specific compounds are used. It can be seen that the time for dispersing to the particle size is considerably shorter and the dispersing time is shorter than in Comparative Example 2 using the conventional antifoaming agent. Therefore, the productivity can be improved by using the specific compound defined in the present invention. In Examples 1 and 2, foaming was efficiently suppressed. However, in Comparative Example 2, foaming was somewhat observed. In Comparative Example 1, in which no specific compound was added, foaming was considerable. Wait before applying. Also,
In Examples 1 and 2, a heat-sensitive recording material having no cracks on the surface and having a good coated surface without coating defects was obtained. In Comparative Example 2 using the conventional antifoaming agent, cracks were formed on the surface. Was.

[0168]

According to the present invention, the bubbling generated when the pigment contained in the protective layer is dispersed is suppressed, the dispersibility of the pigment is improved, and the productivity is improved. It is possible to provide a heat-sensitive recording material having a suitable coated surface. Further, according to the present invention, it is possible to provide a method for producing the above-described excellent thermosensitive recording material.

Claims (10)

[Claims] 1. A heat-sensitive recording material having a heat-sensitive recording layer on a support and a protective layer containing at least a pigment and a binder on the heat-sensitive recording layer, wherein the protective layer has the following general formula (1) ) And the following general formula (2)
A heat-sensitive recording material comprising at least one selected from the group consisting of compounds represented by the formula: Embedded image (In the general formula (1) and the general formula (2), R is a group having 1 to 1 carbon atoms.
6 represents an alkyl group. In the general formula (2), a and b are
a + b represents an integer satisfying 3 to 30. ) 2. The compound represented by the general formula (1) and the compound represented by the general formula (2) are 2,4,7,9
-Tetramethyl-5-decyne-4,7-diol, 2,
Ethylene oxide adduct of 4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,6-dimethyl-4
The heat-sensitive recording material according to claim 1, which is an ethylene oxide adduct of -octin-3,6-diol. 3. The pigment according to claim 1, wherein the pigment is an inorganic pigment surface-coated with at least one selected from the group consisting of higher fatty acids, metal salts of higher fatty acids, higher alcohols, and higher fatty acid amides. Heat-sensitive recording material. 4. The sum of the amounts of the compound represented by the general formula (1) and the compound represented by the general formula (2) is:
0.0 with respect to the addition amount of the pigment contained in the protective layer
The heat-sensitive recording material according to any one of claims 1 to 3, wherein the content is 5 to 4% by weight. 5. 50% of said pigment by laser diffraction method
The volume average particle size is 0.20 to 1.00 µm.
5. The thermosensitive recording material according to any one of items 1 to 4. 6. A step of applying a coating solution for forming a heat-sensitive recording layer on a support to form a heat-sensitive recording layer, and applying a coating solution for forming a protective layer containing at least a pigment and a binder to form a protective layer. Forming a thermosensitive recording material, wherein these steps are performed in this order or simultaneously, wherein the pigment is a compound represented by the following general formula (1) or a compound represented by the following general formula (2): A method for producing a heat-sensitive recording material, characterized by being dispersed in the presence of at least one selected from the group consisting of the compounds represented by the following formula. Embedded image (In the general formula (1) and the general formula (2), R is a group having 1 to 1 carbon atoms.
6 represents an alkyl group. In the general formula (2), a and b are
a + b represents an integer satisfying 3 to 30. ) 7. The compound represented by the general formula (1) and the compound represented by the general formula (2) are 2,4,7,9
-Tetramethyl-5-decyne-4,7-diol, 2,
Ethylene oxide adduct of 4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, and 3,6-dimethyl-4
7. The method for producing a thermosensitive recording material according to claim 6, which is an ethylene oxide adduct of -octin-3,6-diol. 8. The pigment according to claim 6, wherein the pigment is an inorganic pigment surface-coated with at least one selected from the group consisting of higher fatty acids, metal salts of higher fatty acids, higher alcohols, and higher fatty acid amides. Production method of heat-sensitive recording material. 9. The sum of the amounts of the compound represented by the general formula (1) and the compound represented by the general formula (2) is:
0.0 with respect to the addition amount of the pigment contained in the protective layer
The method for producing a thermosensitive recording material according to any one of claims 6 to 8, wherein the content is 5 to 4% by weight. 10. The pigment according to claim 5, wherein the pigment is 5
10. The method for producing a thermosensitive recording material according to claim 6, wherein the thermosensitive recording material is dispersed in a range of 0.20 to 1.00 [mu] m with a volume average particle diameter of 0%.