JPH09142029A - Heat sensitive recording body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make color development density high, eliminate skin color development due to solvent and prevent the occurrence of color fading or color elimination in a recording picture unit by containing a dye precursor, a specified aminobenzen sulfonamide derivative, a specified multi-value phenolic compound and a high-class aliphatic acid metallic salt in a recording layer. SOLUTION: A recording layer, containing at least one kind of aminobenzen sulfonamide derivative, shown by a formula I, at least one kind of multi-value phenolic compound, shown by a formula II, and high-class aliphatic acid metallic salt, is formed on the supporting body of a heat sensitive recording body. In the formulas, X means the atom of oxygen or the atom of sulfur, R means non-replaced or replaced phenyl group, naphthyl group, alalkyl group, alkyl group having the number of carbon of 1-6, cycloalkyl group having the number of carbon of 3-6 of low-class alkenyl group having the number of carbon of 2-6. Z means low-class alkyl group having the number of carbon of 1-6 and shows electron attracting property. (n) is an integer of 0-4, (p) is an integer of 1-5. Provided, n+p>=5.

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 excellent in image storage stability and background stain resistance (background color development), and more particularly to a heat-sensitive recording material having excellent properties against a solvent such as alcohol. It concerns a recording body.

[0002]

2. Description of the Related Art Generally, a thermosensitive recording medium comprises a colorless or light-colored dye precursor and a developer such as a phenolic compound.
After grinding and dispersing each into fine particles, mix both,
A coating liquid obtained by adding a binder, a filler, a sensitivity improver, a lubricant and other auxiliaries to paper, synthetic paper, film,
It is applied on a support such as plastic, and a recorded image is obtained by developing a color by an instantaneous chemical reaction by heating with a thermal head, a hot stamp, a hot pen, a laser beam or the like. These thermal recording media are used for measuring recorders, computer terminal printers, facsimiles,
It has been applied to a wide range of fields such as automatic ticket vending machines and bar code labels, but with the diversification and high performance of these recording devices, the quality requirements for thermal recording sheets have become more sophisticated. There is. For example, with the increase in recording speed, it is required to obtain a clear color image with high density even with a small amount of heat energy, while light resistance, heat resistance, water resistance, oil resistance, solvent (chemical) resistance, Further, a heat-sensitive recording sheet having excellent storage stability such as plasticizer resistance is required.

More recently, as the method of recording on plain paper such as electrophotographic method or ink jet method has become widespread, thermal recording is often compared with these plain paper recording. For example, the stability of an image is as good as that of toner recording, and the stability of a non-recorded portion (white paper portion or background color portion, hereinafter referred to as background color portion) before and after recording (hereinafter referred to as background color stability) Are required to approach the quality of plain paper records.

The heat-sensitive recording material is inevitably in contact with human hands because of its function as an information recording medium, and the hair of a person who uses it daily, such as a hairdressing material, an oily substance such as sebum, or alcohol. Since the above solvent may be attached, the thermal recording material is very often contaminated with these substances. In particular, in the medical field, the cash register related to food and drink, or the measurement field, the frequency of contamination by solvents and various chemicals is high.

However, in general, a thermosensitive recording medium is not sufficiently stable against these oily substances or solvents such as alcohol, and the contacted contaminated portion may cause the disappearance of a color image or the formation of a ground color portion (ground color). Occur. This is because the color development reaction between the dye precursor used as the color development material and the color developer is a reversible reaction, so that the thermosensitive color development layer or the color reaction product is partially dissolved by contact with an oil substance or a solvent that is a pollution source. It is considered that the colored image disappears due to an unstable state. Further, it is considered that the unreacted dye precursor and the color developer cause a color development reaction through an oily substance or a solvent which is a contamination source, so that a ground color is developed.

In order to improve the solvent resistance of these, it has been studied to provide a protective layer on the coloring layer containing the dye precursor and the organic developer to physically prevent contact with a solvent or the like. However, with this method, it is difficult to obtain an excellent protective layer against a pollution source, there is a problem in that the sensitivity is lowered, or there is a problem in economical efficiency, and at present, a satisfactory one is not obtained. is there.

Further, JP-A-60-184879, JP-A-4-144786, or JP-A-4-184786.
JP-A-144787 discloses that a blocked phenol compound, which is a reaction product of an isocyanate compound and a phenol compound, is used as a color developer, whereby a background color development phenomenon due to an unnecessary color development reaction caused by heat, a solvent, or the like occurs. A thermosensitive recording medium that does not wake up is described. The thermal recording material using this dye precursor and a specific developer has improved solvent resistance (prevention of background color development) in the background color area, but the color images are erased or faded. However, it is hard to say that this is a satisfactory color development system from the viewpoint of recording sensitivity.

Therefore, a chelate coloring system using a metal compound is known as opposed to a thermosensitive coloring system using the dye precursor as described above. For example, Japanese Patent Publication No. 32-8787 describes a combination of iron stearate (electron acceptor) and tannic acid or gallic acid (electron donor) as a coloring material. JP-B-34-6485 discloses iron stearate, silver stearate, gold stearate, copper stearate, or mercury behenate as an electron acceptor, and uses methyl gallate, ethyl gallate, propyl gallate, gallic acid. Combinations with butyl or dodecyl gallate as electron donor are described. However, since these thermal recording media are recorded by a thermal copying system using the thermal energy of light, when used in a thermal recording system using a thermal head, dust adhesion and sticking will not occur when the recording surface and the thermal head are in contact with each other. Will occur. Further, the color development (saturation) density is low, the color tone is also lacking in blackness, and there is a problem in visibility, and unrecorded portions, that is, background color portions, have unnecessary coloring and are poor in whiteness. In addition, there is a defect that the color forming layer is lost due to lack of stability against a solvent such as alcohol.

In JP-A-59-89193, in addition to a dye precursor and a color-developing system of a phenol-based developer, a metal compound composed of a higher fatty acid ferric iron salt and a polyvalent hydroxyaromatic compound is used. The combination of color systems is described. However, it is economically difficult because a protective layer is required to hide the coloring, and when the solvent resistance is improved by the protective layer, a solvent such as alcohol easily develops color from pinholes in the protective layer. By penetrating into the layer, it acts on the dye precursor and the developer present in the color forming layer to cause background color development. Furthermore, when a phenol-based developer and a polyvalent hydroxyaromatic compound coexist, a melting point drop occurs between the two and a color-forming reaction is likely to occur, which causes coloration during paint preparation and coloration of the ground color part. There was such a bad effect.

From these things, JP-A-62-1056
JP-A-88 discloses a heat-sensitive recording material containing a long-chain higher fatty acid iron, a polyhydric phenol derivative, and a dye precursor having a limited addition amount (25% by weight or less based on the polyhydric phenol derivative) in a recording layer. Disclosure. However, since the addition amount of the dye precursor is limited, there is a limit in the color development (saturation) density, and the density of the ground color is not satisfactory regardless of the color tone.

On the other hand, the inventors of the present invention have filed Japanese Patent Application No. 6-1000.
82, Japanese Patent Application No. 6-168516, Japanese Patent Application No. 6-187649, Japanese Patent Application No. 6-195568.
Specification, Japanese Patent Application No. 6-270959 Specification, Japanese Patent Application No. 7
No. -97021, Japanese Patent Application No. 7-122393, or Japanese Patent Application No. 7-250789 describes a heat-sensitive recording material using an aminobenzenesulfonamide derivative as a developer. Although these thermosensitive recording materials hardly cause background color development to a solvent such as alcohol, they have a drawback that the recorded image portion is discolored when contacted with a large amount of solvent. Therefore, it cannot be said that the heat-sensitive recording material using this compound and the dye precursor as a color-forming material has complete stability against a solvent such as alcohol.

[0012]

Therefore, in the present invention,
In a heat-sensitive recording material using an aminobenzenesulfonamide derivative, the coloring (saturation) concentration is high and the background color is less colored, and the background color does not develop even when contacted with a solvent such as alcohol, and the recorded image is discolored. It was an object to provide a heat-sensitive recording material that does not cause discoloration.

[0013]

Means for Solving the Problems The above-mentioned problems are as follows: a dye precursor, at least one aminobenzenesulfonamide derivative represented by the following general formula (1), and a general formula ( It was achieved by containing at least one polyhydric phenol compound represented by 2) and a higher fatty acid metal salt.

[0014]

Embedded image (Wherein, X represents an oxygen atom or a sulfur atom;
Is an unsubstituted or substituted phenyl group, naphthyl group, aralkyl group, lower alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, or 2 to 6 carbon atoms.
Represents a lower alkenyl group. Z represents a lower alkyl group having 1 to 6 carbon atoms or an electron-withdrawing group. n represents an integer of 0 to 4, and p represents an integer of 1 to 5. However, n + p ≦
5 is satisfied. )

[0015]

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The aminobenzenesulfonamide derivative represented by the general formula (1) used in the present invention is structurally changed from a neutral type to an acidic type as shown in the following formula by instantaneous heating (when X is an oxygen atom). Is the keto-enol tautomerism)
It is considered that the developing ability is developed by causing the. In the case of a thermosensitive recording medium, the thermal head for supplying heat is instantaneously heated to a high temperature of 200 to 300 ° C. or higher, so that the compound of the general formula (1) contained in the recording layer of the thermosensitive recording medium is tautomeric. To become an acidic type, and the lactone ring of the dye precursor is cleaved to develop a color.

[0017]

Embedded image (In the formula, X represents an oxygen atom or a sulfur atom.)

High temperature is an essential condition for the above-mentioned tautomerism, and it is hardly caused by a solvent or the like. Therefore, when a compound having such characteristics is used, a dye precursor and a color developing reaction are always taken easily by taking an acid type structure such as a phenolic developer such as bisphenol A or bisphenol S well known in the field of thermal recording. The problem of background color development due to a solvent or the like is much smaller than that of a color developer that is easily caused.

In order to stabilize the compound of the general formula (1) used in the present invention against a solvent or the like, an aminosulfonyl group (-SO ₂ NH ₂ ) at the N-position (or 1-position) of the urea structure or the thiourea structure is used. It is considered that having an aromatic ring having Therefore, R in the general formula (1) is not particularly limited as long as it does not impair the color developing ability and stability, and examples thereof include an unsubstituted or substituted phenyl group, a naphthyl group, an aralkyl group, and a carbon number of 1 to 1. 6
And a lower alkyl group having 3 to 6 carbon atoms, or a lower alkenyl group having 2 to 6 carbon atoms. Further, R may be substituted with a substituent that does not impair color development and heat resistance, and examples of the substituent include a lower alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group, and a lower alkyl group such as isopropenyl group. Alkenyl group, or fluorine, chlorine, bromine,
An electron withdrawing group such as a nitro group can be used. Further, Z in the general formula (1) may be a substituent that does not impair the color development and heat resistance. Examples of such a substituent include a lower alkyl group having 1 to 6 carbon atoms such as a methyl group and an ethyl group,
Alternatively, electron withdrawing groups such as fluorine, chlorine, bromine and nitro groups can be mentioned.

Specific examples of the compound represented by the general formula (1) include (A-1) to (A-54) and (B-1) to (B-18) shown below. However, the present invention is not limited to these.

[0021]

[Chemical 6]

[0022]

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[0023]

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[0024]

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The polyhydric phenol compound represented by the general formula (2) used in the present invention has a ligand (OH group) that causes a color change (color development) by a chelate reaction, and is a salt of a higher fatty acid metal salt. By reacting, a chromophore is formed. In the present invention, the polyhydric phenol compound is required to avoid reacting with a higher fatty acid metal salt when preparing a coating liquid by dispersing in a water-based or solvent-based binder, or to enhance dispersion stability. And R ₁ or R ₂ preferably has 18 to 35 carbon atoms. Further, it is desirable that the number of hydroxyl groups is 2 or 3, and that the hydroxyl groups are adjacent to each other.

In the polyhydric phenol compound represented by the general formula (2), G represents a divalent group, and the group R ₁ adjacent thereto is an alkyl group having 18 to 35 carbon atoms, phenyl. Group, benzyl group, naphthyl group, or biphenyl group. As the substituent R ₂ contained in these, an alkyl group having 18 to 35 carbon atoms is desirable. Specific examples of the compound represented by the general formula (2) include (C-1) to (C-23) shown below, but the compound is not limited thereto. Further, these polyhydric phenols may be used alone or in combination of two or more as required.

[0027]

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In the thermosensitive recording medium of the present invention, the polyhydric phenol compound represented by the general formula (2) and the general formula (1) are used.
Both of the aminobenzenesulfonamide derivatives represented by the formula (1) are contained in the recording layer. However, the compound of the general formula (1) exhibits the color developing ability by tautomerism as described above, and is instantly strong. Tautomerization occurs only when energy is supplied, that is, the structure does not become acidic unless a high temperature is applied by a thermal head or the like. Therefore, even when the polyhydric phenol compound of the general formula (2) and the polyhydric phenol compound of the general formula (2) are simultaneously present at a temperature in the range of 100 ° C. or lower, the compound of the general formula (1) remains a neutral structure. Compared with the case where other phenol-based color developers and the like are present at the same time, unnecessary coloring reaction does not occur and coloring is less likely to occur.

Further, the compound of the general formula (2) is a phenolic compound and may react with the dye precursor,
Since it has a long-chain alkyl group in its structure, its solubility in a solvent or the like is extremely low. Therefore, even when it comes into contact with a solvent or the like, the degree of causing a color reaction with a dye precursor is small, and it is possible to suppress coloring of the ground color portion.

The higher fatty acid metal salt used in the present invention is, in view of solubility in various solvents involved in solvent resistance,
Particularly, a higher fatty acid metal single salt having a saturated or unsaturated fatty acid group having 16 to 35 carbon atoms or a higher fatty acid metal double salt containing two or more metals is desirable. As the metal of the higher fatty acid metal salt, iron, zinc, calcium, magnesium, aluminum, barium, lead, excluding alkali metals,
Manganese, nickel, cobalt, copper, silver, mercury or the like is preferable. Further, the ratio of the metal double salt, the color developability,
Alternatively, it can be freely selected according to a desired purpose such as dispersibility.

For example, the higher fatty acid metal salt used in the present invention can be obtained by reacting an alkali metal salt or ammonium salt of a higher fatty acid with an inorganic metal salt containing a desired metal. The higher fatty acid metal double salt is prepared by the same method, but it is synthesized by using two or more kinds of inorganic metal salts in combination during the reaction. Therefore, the type of metal atoms in the double salt and the mixing ratio thereof can be freely controlled during this preparation. As an example, by reacting an aqueous solution of sodium behenate with a mixed solution of ferric chloride and zinc chloride in a molar ratio of 2: 1, iron / zinc behenate containing iron and zinc in a ratio of 2: 1 can be obtained. can get.

Examples of typical higher fatty acid metal salts include, but are not limited to, the following. In addition, these higher fatty acid metal salts may be used alone or in combination of two or more as required.

Iron stearate (D-1) Iron behenate (D-2) Iron montanate (D-3) Iron oxide wax (D-4) Iron stearate / Zinc double salt (D-5) ) Iron behenate / zinc double salt (D-6) Iron behenate / calcium double salt (D-7) Iron behenate / aluminum double salt (D-8) Iron behenate / magnesium double salt (D-9) Behen Iron oxide / silver double salt (D-10) Silver behenate / calcium double salt (D-11) Silver behenate / zinc double salt (D-12) Silver behenate / magnesium double salt (D-13) Calcium behenate・ Aluminum double salt (D-14) Iron montanate / zinc double salt (D-15) Acid wax Iron / zinc double salt (D-16)

In the heat-sensitive recording material of the present invention, the polyhydric phenol compound represented by the general formula (2) and the higher fatty acid metal salt cause a metal chelate reaction by the heat energy supplied from the thermal head to form a colored product. To do.
This reaction is an irreversible reaction, which is different from the color development due to the reversible reaction between the dye precursor and the aminobenzenesulfonamide derivative represented by the general formula (1), and the metal chelate product has a long-chain alkyl group in its structure. Extremely stable due to the presence of a group. Therefore, a highly stable color image that does not change even when contacted with a solvent or the like can be obtained.

On the other hand, in many cases, a colored image formed by metal chelate type coloring gives a good black image, and the recording density is low in many cases. On the other hand, in the present invention, when a black coloring dye precursor is used, the extinction coefficient of the coloring product obtained by reacting this with the compound of the general formula (1) is high, so that a metal chelate type coloring product is obtained. It is possible to compensate for the recording density and color tone of.

Further, among the thermosensitive coloring materials utilizing the metal chelate reaction, some higher fatty acid metal salts are originally colored, and the tendency is remarkable especially for those showing high coloring properties. Therefore, the background color of the thermosensitive recording medium using a metal chelate type thermosensitive coloring material as a main component is often inferior in whiteness. In the present invention, the dye precursor and the general formula (1)
The recording layer also contains a leuco-type thermosensitive coloring material that utilizes the coloring reaction with an aminobenzenesulfonamide derivative, and the content ratio of higher fatty acid metal salts is higher than that of the metal chelate-type coloring material alone. Can be suppressed, so that the whiteness of the background color can be enhanced.

Further, the heat-sensitive recording material of the present invention has excellent solvent resistance to the alcohol in both the ground color portion and the image portion, as shown in Examples described later. It is similarly effective for such a solvent.

As the colorless or light-colored dye precursor to be used in the heat-sensitive recording material of the present invention, all those known in the conventional pressure-sensitive or heat-sensitive recording paper field can be used and are not particularly limited. , Triphenylmethane compounds, fluorane compounds, fluorene compounds, divinyl compounds and the like are preferable. Specific examples of typical dye precursors are shown below. These dye precursors may be used alone or in combination of two or more.

<Triphenylmethane Leuco Dye> 3,
3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide [also known as crystal violet lactone] 3,3-bis (p-dimethylaminophenyl) phthalide [also known as malachite green lactone] <fluoran-based leuco dye> 3- Diethylamino-6-
Methylfluorane 3-diethylamino-6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluorane 3-diethylamino-6-methyl-7-chlorofluorane 3-Diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-7- (o-chloroanilino) fluorane 3-diethylamino-6-methyl-7- (p-chloroanilino ) Fluoran 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluorane 3-diethylamino-6-methyl-7-n-octyl anilinofluorane 3-diethylamino-6-methyl-7-n-octyl Aminofluorane 3-diethylamino-6-methyl-7-benzylani Rinofluorane 3-diethylamino-6-methyl-7-dibenzylanilinofluorane 3-diethylamino-6-chloro-7-methylfluorane 3-diethylamino-6-chloro-7-anilinofluorane 3-diethylamino-6- Chloro-7-p-methylanilinofluorane 3-diethylamino-6-ethoxyethyl-7-anilinofluorane 3-diethylamino-7-methylfluorane 3-diethylamino-7-chlorofluorane 3-diethylamino-7- (M-Trifluoromethylanilino) fluorane 3-diethylamino-7- (o-chloroanilino) fluorane 3-diethylamino-7- (p-chloroanilino) fluorane 3-diethylamino-7- (o-fluoroanilino) fluorane 3- Diethylamino-benzo [a Fluorane 3-diethylamino-benzo [c] fluorane 3-dibutylamino-6-methyl-fluorane 3-dibutylamino-6-methyl-7-anilinofluorane 3-dibutylamino-6-methyl-7- (o, p -Dimethylanilino) fluorane 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluorane 3-dibutylamino-6-methyl-7- (p-chloroanilino) fluorane 3-dibutylamino-6-methyl-7 -(O-Fluoroanilino) fluorane 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-dibutylamino-6-methyl-chlorofluorane 3-dibutylamino-6-ethoxy Ethyl-7-anilinofluorane 3-dibutylamino-6-chloro-7-ani Rinofluoran 3-dibutylamino-6-methyl-7-p-methylanilinofluorane 3-dibutylamino-7- (o-chloroanilino) fluorane 3-dibutylamino-7- (o-fluoroanilino) fluoran 3-n -Dipentylamino-6-methyl-7-anilinofluorane 3-n-dipentylamino-6-methyl-7- (p-chloroanilino) fluorane 3-n-dipentylamino-6-chloro-7-anilinofluorane 3-n-dipentylamino-7- (p-chloroanilino) fluorane 3-n-dipentylamino-7- (m-trifluoromethylanilino) fluorane 3-pyrrolidino-6-methyl-7-anilinofluorane 3- Piperidino-6-methyl-7-anilinofluorane 3- (N-methyl-N-propylamino) 6-methyl-7-anilinofluoran 3- (N- methyl -N- cyclohexylamino) -6-
Methyl-7-anilinofluorane 3- (N-ethyl-N-cyclohexylamino) -6-
Methyl-7-anilinofluoran 3- (N-ethyl-N-xylamino) -6-methyl-
7- (p-chloroanilino) fluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-chloro-7-anilino Fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran 2- (4-oxahexyl) -3-dimethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-diethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-dipropylamino-
6-methyl-7-anilinofluoran 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluoran 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2 -Chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-amino-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2- Benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2-hydroxy-6-p- (p-phenylaminophenyl) aminoanilinofluoran 3-methyl-6-p- (p-dimethyl Aminophenyl)
Aminoanilinofluorane 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane 2,4-dimethyl- 6-[(4-Dimethylamino) anilino] -fluorane <fluorene-based leuco dye> 3,6,6′-tris (dimethylamino) spiro [fluorene-9,3′-phthalide] 3,6,6′-tris (Diethylamino) spiro [fluorene-9,3'-phthalide] <Divinyl-based leuco dye> 3,3-bis- [2- (p-
Dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,5,6,7-tetrabromophthalide 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrachlorophthalide 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide 3,3- Bis- [1- (4-methoxyphenyl) -1-
(4-pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-Tetrachlorophthalide <Others> 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindole-
3-yl) -4-azaphthalide 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) ) -4-Azaphthalide 3,3-bis (1-ethyl-2-methylindole-3)
-Yl) phthalide 3,6-bis (diethylamino) fluorane-γ- (3
′ -Nitro) anilinolactam 3,6-bis (diethylamino) fluorane-γ- (4
'-Nitro) anilinolactam 1,1-bis- [2', 2 ', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-dinitrileethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2-
β-naphthoylethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-Diacetylethane bis- [2,2,2 ', 2'-tetrakis- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

In the present invention, conventionally known sensitizers can be used as long as the desired effects for the above problems are not impaired. Examples of such a sensitizer include fatty acid amides such as stearic acid amide and palmitic acid amide, ethylene bisamide, montanic acid wax, polyethylene wax, 1,2-di- (3-methylphenoxy) ethane, p-benzylbiphenyl, β- Benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-terphenyl, 1,2-diphenoxyethane, dibenzyl oxalate, di (p-chlorobenzyl oxalate), di (p-methylbenzyl) oxalate, Dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p-tolyl carbonate, phenyl-α-naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-
Examples thereof include 2-naphthoic acid phenyl ester, o-xylelin-bis- (phenyl ether), and 4- (m-methylphenoxymethyl) biphenyl, but they are not particularly limited thereto. You may use these sensitizers individually or in mixture of 2 or more types.

As the binder used in the present invention, completely saponified polyvinyl alcohol having a degree of polymerization of 200 to 1900, partially saponified polyvinyl alcohol, carboxy modified polyvinyl alcohol, amide modified polyvinyl alcohol, sulfonic acid modified polyvinyl alcohol, butyral modified polyvinyl. Modified polyvinyl alcohol such as alcohol, cellulose derivative such as hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, acetyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, polyacrylamide , Polyacrylic acid ester, polyvinyl butyral, polystyrene and their copolymers, polyamide resin, silicone Butter, petroleum resins, terpene resins, ketone resins, and coumarone resins. These polymeric substances include water, alcohol, ketones, esters,
In addition to being used by being dissolved in a solvent such as a hydrocarbon, it may be used in a state of being emulsified in water or another medium or dispersed in a paste form, and may be used together depending on the required quality.

Further, in the present invention, p-nitrobenzoic acid metal salt (Ca, Zn), which is a known stabilizer showing an oil resistance effect of a recorded image, etc., within a range that does not impair the desired effect for the above problems, Alternatively, phthalic acid monobenzyl ester metal salt (Ca, Zn) can be added.

As the filler which can be used in the present invention, silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene- Examples thereof include methacrylic acid copolymers, styrene-butadiene copolymers, and inorganic or organic fillers such as hollow plastic pigments.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based and triazole-based UV absorbers, waterproofing agents such as glyoxal, dispersants, defoamers, antioxidants, and fluorescent agents. A dye or the like can be used.

As the support used in the present invention, paper, synthetic paper, plastic film, non-woven fabric, metal foil and the like can be used, and a composite sheet in which these are combined may be used.

An overcoat layer of a polymeric substance or the like may be provided on the thermosensitive coloring layer for the purpose of further improving the storage stability. By forming the overcoat layer, further solvent resistance can be imparted. Further, an undercoat layer containing an organic filler or an inorganic filler may be provided between the color forming layer and the support for the purpose of enhancing the storage stability and sensitivity.

The heat-sensitive recording material of the present invention can be made into a heat-sensitive recording material capable of optical recording by containing a light absorbing agent which absorbs light and converts it into heat in the heat-sensitive recording layer or other layers. . As the light absorber for converting light into heat used in the thermal recording medium of the present invention, any substance that absorbs the emission wavelength of various light sources may be used, and various dyes, various pigments, near infrared absorbers and the like are used. It is possible and is not particularly limited. The amount of the light absorbing agent to be added is determined according to the light absorbing performance and the like.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION In order to obtain the aminobenzenesulfonamide derivative represented by the general formula (1) of the present invention, as an example, aminobenzenesulfonamide having an aminosulfonyl group and isocyanic acid ester, Alternatively, it can be produced by the reaction of isothiocyanates. That is, in the reaction, 1 to 2.5 mol of the isocyanic acid ester or isothiocyanic acid ester is added to 1 mol of the aminobenzenesulfonamide. As the solvent to be used, it is sufficient if it can dissolve the aminobenzenesulfonamide, isocyanic acid ester, or isothiocyanic acid ester, for example, aromatic hydrocarbons such as benzene, toluene, xylene, chloroform, dichloromethane, Halogenated aromatic hydrocarbons such as chlorobenzene, ethers such as diethyl ether and tetrahydrofuran,
Nitriles such as acetonitrile and propionitrile,
Examples thereof include esters such as ethyl acetate, ketones such as acetone and methyl ethyl ketone, aproton-donating polar solvents such as dimethylformamide and dimethylsulfoxide, alcohols such as methanol and ethanol, and mixed solvents thereof. The reaction temperature is in the range of 0 to 150 ° C.

A general method for producing the heat-sensitive recording material of the present invention is represented by a dye precursor, at least one aminobenzenesulfonamide derivative represented by the general formula (1), and a general formula (2). At least one polyhydric phenol compound and a higher fatty acid metal salt are each dispersed together with a binder, and a particle diameter of several microns or less is obtained by a pulverizer such as a ball mill, attritor, or sand grinder, or an appropriate emulsifying device. By atomizing, adding a filler, a lubricant, an ultraviolet absorber, a water-proofing agent, an antifoaming agent, and other auxiliary agents as necessary to prepare a coating solution, and applying it on a support by a usual method, followed by drying. To manufacture. Examples of the coating method include a size press coater method, a roll coater method, an air knife coater method, a blend coater method, a flow coater method, a comma direct method, a gravure direct method, a gravure reverse method and a reverse roll coater method. In addition, the coating liquid may be sprayed, sprayed or dipped and then dried.

The amount of the dye precursor and the compound of the general formula (1) used in the heat-sensitive recording material of the present invention, and the kind and amount of the polyhydric phenol compound, the higher fatty acid metal salt and other various components are required performances. And, although not particularly limited, usually 1 to 8 parts of the compound of the general formula (1) and 0.5 to 0.5 parts of the compound of the general formula (2) per 1 part of the dye precursor. 8 parts, higher fatty acid metal salt 0.5
-10, 1 to 20 parts of filler is used, and 10 to 25% of the total solid content of the binder is suitable. Further, when the total number of parts of the polyhydric phenol compound and the higher fatty acid metal salt is about 0.4 to 2 times the total number of parts of the dye precursor and the compound of the general formula (1), the recorded image and the background color are A heat-sensitive recording material having a good balance of solvent resistance and whiteness of the background color can be obtained.

[0051]

【Example】

<< Production of Thermal Recording Material; Examples 1 to 16 and Comparative Examples 1 to 8
>> The following describes the thermosensitive recording medium of the present invention with reference to examples. In the description, parts and% are parts by weight and weight%, respectively.
Is shown. Various solutions, dispersions, or coating solutions were prepared as follows.

[Examples 1 to 14] The aminobenzenesulfonamide derivative represented by the general formula (1) has the above-mentioned (A-
1) to (A-54). The dye precursor is 3-
Diethylamino-6-methyl-7-anilinofluorane (hereinafter referred to as ODB) and 3-dibutylamino-6-methyl-7-anilinofluorane (hereinafter referred to as ODB2)
I chose either. The polyhydric phenol compound represented by the general formula (2) was selected from the above (C-1) to (C-23). Further, the higher fatty acid metal salt is the above-mentioned (D-1).
~ (D-16), iron stearate (D-
1), iron behenate (D-2), iron stearate / zinc double salt (D-5 content ratio 3: 2), iron behenate
Zinc double salt (D-6 with a content ratio of 2: 1), iron behenate / calcium double salt (D-7 with a content ratio of 1: 1), iron behenate / silver double salt (with D-10) 2: 1 content ratio), silver behenate / zinc double salt (D-12 content ratio 3 :)
2) and a silver behenate / magnesium double salt (having a content ratio of D-13 of 5: 2). Separately, a developer dispersion (liquid A), a dye precursor dispersion (solution B), a polyhydric phenol compound dispersion (solution C), and a higher fatty acid metal salt dispersion (solution D) having the following formulations are separately prepared. Wet grinding was performed with a sand grinder until the average particle size became 1 micron. Liquid A (developing agent dispersion) Developer of general formula (1) 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts water 11.2 parts Liquid B (dye precursor dispersion) 3-diethylamino-6 -Methyl-7-anilinofluorane (ODB) 2.0 parts 10% aqueous solution of polyvinyl alcohol 4.6 parts water 2.6 parts C liquid (polyhydric phenol compound dispersion) polyhydric phenol compound of general formula (2) 3.0 parts 10% polyvinyl alcohol aqueous solution 9.4 parts water 5.6 parts liquid D (higher fatty acid metal salt dispersion) higher fatty acid metal salt 3.0 parts 10% polyvinyl alcohol aqueous solution 9.4 parts water 5.6 parts Next, the dispersions were mixed in the following proportions to prepare a coating liquid for the recording layer. Recording layer coating liquid A liquid (developer dispersion liquid) 36.0 parts B liquid (dye precursor dispersion liquid) 9.2 parts C liquid (polyhydric phenol compound dispersion liquid) 18.0 parts D liquid (higher fatty acid metal) Salt dispersion) 18.0 parts Kaolin clay (50% dispersion) 12.0 parts Next, the recording layer coating liquid was applied to one side of a support (60 g / m ² base paper), and then dried. The sheet was treated with a super calender so as to have a smoothness of 500 to 600 seconds to obtain a recording layer having a coating amount of 6.0 g / m ² .

Example 15 The dispersion liquids of the liquids A, B, C and D were mixed in the following proportions to prepare a coating liquid for the recording layer. Recording layer coating liquid A liquid (developer dispersion liquid) 27.0 parts B liquid (dye precursor dispersion liquid) 6.9 parts C liquid (polyhydric phenol compound dispersion liquid) 24.0 parts D liquid (higher fatty acid metal) Salt dispersion liquid) 24.0 parts Kaolin clay (50% dispersion liquid) 12.0 parts Then, the recording layer coating liquid is applied to one side of the support (60 g / m ² base paper) and then dried. The sheet was treated with a super calender so as to have a smoothness of 500 to 600 seconds to obtain a recording layer having a coating amount of 6.0 g / m ² .

[Example 16] The dispersion liquids of the liquids A, B, C and D were mixed in the following proportions to prepare coating liquids for recording layers. Recording layer coating liquid A liquid (developer dispersion liquid) 45.0 parts B liquid (dye precursor dispersion liquid) 11.5 parts C liquid (polyhydric phenol compound dispersion liquid) 12.0 parts D liquid (higher fatty acid metal) Salt dispersion) 12.0 parts Kaolin clay (50% dispersion) 12.0 parts Next, the recording layer coating liquid is applied to one side of the support (60 g / m ² base paper) and then dried. The sheet was treated with a super calender so as to have a smoothness of 500 to 600 seconds to obtain a recording layer having a coating amount of 6.0 g / m ² .

Comparative Example 1 Bisphenol A (hereinafter referred to as BPA) was used as a color developer, and a dispersion liquid (E
Liquid) was wet-ground with a sand grinder until the average particle size became 1 micron. Liquid E (BPA dispersion liquid) BPA 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts water 11.2 parts Next, liquid E and liquid B are mixed with the dispersion liquid at the following ratios to form a coating liquid for the recording layer. And Recording layer coating liquid E liquid (BPA dispersion liquid) 36.0 parts Liquid B (dye precursor dispersion liquid) 9.2 parts Kaolin clay (50% dispersion liquid) 12.0 parts Next, the recording layer coating liquid was used as a support ( (60 g / m ² of base paper) and then dried, and this sheet is processed with a super calender to have a smoothness of 500 to 600 seconds, and a recording layer having a coating amount of 6.0 g / m ² Got

[Comparative Example 2] The same treatment was carried out except that the E liquid of Comparative Example 1 was replaced with the A liquid.

[Comparative Example 3] The same treatment was carried out as in Examples 1 to 14 except that the solution A was replaced with the solution E.

[Comparative Example 4] Using diphenylthiourea (hereinafter referred to as DPTU) as a developer, a dispersion liquid (E 'liquid) having the following composition was wet-milled with a sand grinder until the average particle diameter became 1 micron. went. E liquid (DPTU dispersion liquid) BPA 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts Next, E'liquid and the said liquid B, liquid C, and liquid D at the following ratios To prepare a coating liquid for the recording layer. Recording layer coating liquid E ′ liquid (DPTU dispersion liquid) 36.0 parts B liquid (dye precursor dispersion liquid) 9.2 parts C liquid (polyhydric phenol compound dispersion liquid) 18.0 parts D liquid (higher fatty acid metal salt) Dispersion) 18.0 parts Kaolin clay (50% dispersion) 12.0 parts Next, the recording layer coating liquid is applied to one side of a support (60 g / m ² base paper) and then dried to obtain this sheet. Was processed with a super calender to have a smoothness of 500 to 600 seconds to obtain a recording layer having a coating amount of 6.0 g / m ² .

[Comparative Example 5] The same treatment was carried out except that the solution A of Examples 1 to 14 was removed.

[Comparative Example 6] The same treatment was carried out except that the solutions A and B of Examples 1 to 14 were removed.

Comparative Example 7 Propyl gallate was used as a polyhydric phenol compound, and a dispersion liquid (F liquid) having the following composition was wet-milled with a sand grinder until the average particle diameter became 1 micron. Solution F (propyl gallate dispersion) Propyl gallate 3.0 parts 10% aqueous polyvinyl alcohol solution 9.4 parts water 5.6 parts Next, the solution F and the solutions A, B and D are in the following proportions. The dispersions were mixed to prepare a coating liquid for the recording layer. Recording layer coating liquid A liquid (developer dispersion liquid) 36.0 parts B liquid (dye precursor dispersion liquid) 9.2 parts F liquid (propyl gallate dispersion liquid) 18.0 parts D liquid (higher fatty acid metal salt) Dispersion) 18.0 parts Kaolin clay (50% dispersion) 12.0 parts Next, the recording layer coating liquid is applied to one side of a support (60 g / m ² base paper) and then dried to obtain this sheet. Was processed with a super calender to have a smoothness of 500 to 600 seconds to obtain a recording layer having a coating amount of 6.0 g / m ² .

[Comparative Example 8] Iron benzoate was used as the metal salt, and the following blended dispersion liquid (G liquid) was wet-milled with a sand grinder until the average particle diameter became 1 micron. Liquid G (iron benzoate dispersion liquid) Iron benzoate 3.0 parts 10% polyvinyl alcohol aqueous solution 9.4 parts Water 5.6 parts Next, the liquid G and the liquids A, B, and C are in the following proportions. The dispersions were mixed to prepare a coating liquid for the recording layer. Recording layer coating liquid A liquid (developing agent dispersion liquid) 36.0 parts B liquid (dye precursor dispersion liquid) 9.2 parts C liquid (polyhydric phenol compound dispersion liquid) 18.0 parts G liquid (iron benzoate) Dispersion) 18.0 parts Kaolin clay (50% dispersion) 12.0 parts Next, the recording layer coating liquid is applied to one side of a support (60 g / m ² base paper) and then dried to obtain this sheet. Was processed with a super calender to have a smoothness of 500 to 600 seconds to obtain a recording layer having a coating amount of 6.0 g / m ² .

<< Evaluation of Thermal Recording Material; Examples 1 to 16,
Comparative Examples 1 to 8 >> The thermal recording materials of Examples 1 to 16 and Comparative Examples 1 to 8 were subjected to a thermal recording property test (recording density, background color density) and a solvent resistance test (Table 1, “Implementation”). Examples 1-
16 thermal recording characteristics (recording sensitivity, background color) and solvent resistance ", and Table 2" Thermal recording characteristics (recording sensitivity, background color) and solvent resistance of Comparative Examples 1 to 8 ").

[Thermal recording property test (dynamic color density, see Tables 1 and 2)] A TH-PMD (a thermal recording paper printing tester, Kyocera, equipped with a thermal head) manufactured by Okura Electric Co., Ltd. was used. Thermal recording was performed on the thermal recording bodies of Examples 1 to 16 and Comparative Examples 1 to 8 with an applied energy of 0.41 mj / dot. The recording density of the recording unit is Macbeth densitometer (RD-9
14, using an amber filter, and the same conditions below). Regarding the background color, the density was measured by the same method as described above. In addition, the color was visually judged. The thermosensitive recording materials of Examples 1 to 16 of the present invention were provided with a sufficient recording density by a printer. The background color was white and no coloring was observed. On the other hand, in the thermosensitive recording materials of Comparative Examples 3 to 8, coloring was observed in the ground color portion, and in particular Comparative Example 6 using only the coloring system of the polyhydric phenol compound and the higher fatty acid metal salt.
Also, in Comparative Example 7 using a compound other than the compound represented by the general formula (2) of the present invention, the tendency was remarkable.

[Solvent resistance test] 0.2 ml of ethanol was dropped on the recorded image and the background color portion (background portion) of the thermosensitive recording material recorded by the above method, and after 24 hours, the concentration of the portion was measured. It was Further, ethanol was impregnated with the heat-sensitive recording material recorded by the above-mentioned method, taken out after 1 hour, dried and measured for concentration. In the heat-sensitive recording materials of Examples 1 to 16 of the present invention, the fading of the recorded image portion was small, and the ground color contamination was extremely small. Even when immersed in ethanol, the fading of the color image obtained with the thermosensitive recording medium of the present invention was very small as compared with the comparative example. On the other hand, in Comparative Examples 1 and 2 not containing a polyhydric phenol compound and a higher fatty acid metal salt, or Comparative Examples 3 and 4 using a developer other than the compound represented by the general formula (1) of the present invention. , The fading of the image area was severe due to the effect of ethanol. Further, in the thermosensitive recording medium of Comparative Example, the contamination of the ground color part with ethanol was observed except for Comparative Example 6, and in particular, Comparative Example 3 using a color developing agent different from the compound of the general formula (1) was used. , And Comparative Examples 7 and 8 in which the combination of the polyhydric phenol of the general formula (2) of the present invention and the higher fatty acid metal salt was not used, the coloring of the background color portion was remarkable.

[0066]

[Table 1]

[Table 2]

As is clear from Tables 1 and 2, in the examples of the present invention, the heat-sensitivity of excellent quality performance in the recording density of the image part, the whiteness of the background color part, and the solvent resistance of the image part and the background color part. A recording body is obtained. On the other hand, in the comparative example, a heat-sensitive recording material having a good balance of quality, such as poor whiteness of the background color portion and solvent resistance, regardless of the recording density, could not be obtained.

[0068]

The colorless or light-colored dye precursor, the compound represented by the general formula (1), the polyhydric phenol compound represented by the general formula (2), and the higher fatty acid metal salt are placed in the recording layer. The heat-sensitive recording material of the present invention contains a color (saturation).
Due to its high density and high whiteness, it has excellent contrast between the recorded image part and the background color part, and it does not cause the background color to develop even if it comes in contact with a large amount of solvent, and the recorded image part does not fade. Have The effects of the present invention can be summarized as follows.

(1) Since it has extremely strong stability against a solvent, it is very practical because contamination of the background color portion and discoloration of a recorded image do not occur. For example, in the conventional medical field, food and drink field, or research field, measurement field of test institutions, etc., the use of a large amount of solvent was considered, and restrictions and cautions were required in the use of the thermal recording medium, but the thermal recording medium of the present invention For example, it can be handled in the same way as ordinary paper. (2) In the heat-sensitive recording material of the present invention, it is possible to form a recording layer excellent in heat-sensitive recording suitability such as recording density and also excellent in stability such as solvent resistance by at least one coating, It is economical because it does not require other means such as a protective layer. (3) The conventional thermal recording material having solvent resistance has a recording sensitivity,
Although the thermal recording material of the present invention has some drawbacks in background color, coating suitability, or economical efficiency, these thermal recording materials have all these drawbacks solved, and the thermal recording apparatus which is usually used has a wide range of applications. Can be applied to.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Chuichi Fukuchi 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside Nippon Paper Industries Co., Ltd. Product Development Laboratory

Claims (2)

[Claims] 1. A colorless or light-colored dye precursor, at least one aminobenzenesulfonamide derivative represented by the following general formula (1), and at least 1 represented by the following general formula (2) on a support. A thermosensitive recording medium comprising a recording layer containing a polyphenol compound of one kind and a higher fatty acid metal salt. Embedded image (Wherein, X represents an oxygen atom or a sulfur atom;
Is an unsubstituted or substituted phenyl group, naphthyl group, aralkyl group, lower alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, or 2 to 6 carbon atoms.
Represents a lower alkenyl group. Z represents a lower alkyl group having 1 to 6 carbon atoms or an electron-withdrawing group. n represents an integer of 0 to 4, and p represents an integer of 1 to 5. However, n + p ≦
5 is satisfied. ) 2. The higher fatty acid metal salt has 16 to 16 carbon atoms.
Higher fatty acid metal single salt having 35 fatty acid groups or 2
A higher fatty acid metal double salt containing the above metal, wherein the metal is iron, zinc, calcium, magnesium, aluminum,
Barium, lead, manganese, nickel, cobalt, copper,
The thermal recording medium according to claim 1, wherein the thermal recording medium is selected from silver and mercury.