Thermosensitive recording material

Abstract

(In formula (1), R 1 ~R 10 each independently represents a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, an alkoxy group, an aryloxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a monoalkylamino group, a dialkylamino group or an arylamino group).

Description

Technical Field

[0001] The present invention relates to a heat-sensitive recording material that develops color by the reaction of a chromogenic dye and a developer. Background Art

[0002] Heat-sensitive recording materials are usually obtained by separately dispersing a leuco dye and a developer such as a phenolic compound into fine particles, then mixing the two and adding additives such as a binder, a sensitizer, a filler, and a lubricant to obtain a coating liquid, and coating the coating liquid on paper, a film, synthetic paper, etc. And a color-developed record is obtained by a chemical reaction in which one or both of the leuco dye and the developer are melted and brought into contact by heating. To develop color such a heat-sensitive recording material, a thermal printer equipped with a thermal head is used. Compared with other recording methods, this heat-sensitive recording method is widely used in printers for facsimile machines, computer outputs, calculators, medical test recorders, ticket vending machines, heat-sensitive recording type labels, etc. because of the following characteristics: (1) no noise is generated during recording, (2) no developing and fixing are required, (3) no maintenance is required, and (4) the machine is relatively inexpensive.

[0003] In recent years, with the expansion of the uses of heat-sensitive recording materials, the demand for high-speed recording has been further increased, and there is a strong expectation for the development of a heat-sensitive recording material with excellent heat responsiveness that can sufficiently cope with high-speed recording. In order to meet such requirements, research and development of chromogenic dyes, developers, storage stabilizers, etc. have been carried out, but no material that can sufficiently satisfy the balance between the sensitivity of color development and the storage stability of images has been found.

[0004] Generally, color-developing compounds having a phenolic hydroxyl group have high color-developing ability. Among them, bisphenol compounds have been reported in large numbers due to their high color density, and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) (Patent Document 1) and 4,4'-dihydroxydiphenyl sulfone (bisphenol S) (Patent Document 2) have been proposed. However, since their melting points are high, their heat responsiveness is poor, and they have the disadvantages of poor water resistance of the printed part and poor heat resistance of the background.

[0005] In response to this, a heat-sensitive recording material using a specific color-developing compound having excellent water resistance in the printed part and showing high stability to heat in the background has been disclosed (Patent Document 3), but the plasticizer resistance in the printed part cannot be said to be sufficient. In addition, as color-developing compounds showing high storage stability to plasticizers, a diphenyl sulfone crosslinked compound (Patent Document 4) and a urethane carbamate compound (Patent Document 5) have been proposed, but there is a problem of low heat responsiveness.

[0006] On the other hand, a thermosensitive recording material that improves the storage stability of a printed portion by using a specific color-developing compound and a urethane carbamate compound in combination has been disclosed. However, in the case of combining the urethane carbamate compound, the background fog (ground fog) generated when stored in a high-humidity environment is significant. Therefore, it has become a problem to balance the storage stability of the printed portion and the background while having thermal responsiveness.

[0007] Prior art documents

[0008] Patent documents

[0009] Patent Document 1: U.S. Patent No. 3,539,375

[0010] Patent Document 2: Japanese Unexamined Patent Application Publication No. 57-11088

[0011] Patent Document 3: International Publication No. 2017 / 111032

[0012] Patent Document 4: Japanese Unexamined Patent Application Publication No. 08-333329

[0013] Patent Document 5: Japanese Unexamined Patent Application Publication No. 2000-143611

[0014] Non-patent documents

[0015] Non-Patent Document 1: European Journal of Medicinal Chemistry (2017), 125, 865-880 Summary of the invention

[0016] Problems to be solved by the invention

[0017] An object of the present invention is to provide a recording material and a recording sheet that use a non-phenolic compound as a color developer and have excellent water resistance in the printed portion and good heat resistance in the background portion with respect to such prior art.

[0018] Means for solving the problems

[0019] The inventors of the present invention repeatedly conducted in-depth research to achieve the above object, and as a result, newly found that a thermosensitive recording material using a compound represented by the following general formula (1) as a color-developing compound has excellent water resistance in the printed portion and excellent heat resistance in the background portion, thereby completing the present invention.

[0020] That is, the present invention relates to the following:

[0021] [1] A thermosensitive recording material, wherein the thermosensitive recording material contains a compound represented by the following general formula (1),

[0022]

[0023] (In formula (1), R 1 ~R 10 each independently represents a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, a hydroxyl group, an alkoxy group, an aryloxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a monoalkylamino group, a dialkylamino group, or an arylamino group).

[0024] [2] A heat-sensitive recording material, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

[0025]

[0026] (In formula (2), R 1 ~R 3 has the same meaning as described above.)

[0027] [3] The heat-sensitive recording material according to [1] or [2], wherein, in the general formula (1), R 1 ~R 3 each independently is a hydrogen atom or a methyl group.

[0028] [4] A heat-sensitive recording layer, wherein the heat-sensitive recording layer contains the heat-sensitive recording material according to any one of [1] to [3].

[0029] [5] A heat-sensitive recording paper, wherein the heat-sensitive recording paper contains the heat-sensitive recording layer according to [4].

[0030] Advantages of the Invention

[0031] According to the present invention, it is possible to provide a heat-sensitive recording material having excellent color developability and water resistance in the printed portion and excellent heat resistance in the background portion. Detailed Description of the Invention

[0032] The present invention will be described in detail based on the embodiments, but is not limited to the embodiments shown below. The present invention relates to a heat-sensitive recording material containing the compound represented by the above general formula (1) as a color-developing compound, and a heat-sensitive recording layer and a heat-sensitive recording paper containing the heat-sensitive recording material.

[0033] In one embodiment of the present invention, as the halogen atom in R 1 ~R 10 in the general formula (1), a fluorine atom, a chlorine atom, or a bromine atom can be mentioned, and a fluorine atom or a chlorine atom is preferred.

[0034] In one embodiment of the present invention, as R 1 ~R 10The alkyl group in [it] may include linear alkyl groups, branched alkyl groups or cyclic alkyl groups, among which linear alkyl groups or branched alkyl groups are preferred, and linear alkyl groups are more preferred. The number of carbon atoms in the alkyl group generally ranges from C1 to C12, preferably from C1 to C8, more preferably from C1 to C6, and further preferably from C1 to C4. Specific examples of the alkyl group may include: linear alkyl groups such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, isohexyl, isooctyl; cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0035] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 The alkoxy group in [it] may include: linear alkoxy groups, branched alkoxy groups or cyclic alkoxy groups, among which linear alkoxy groups or branched alkoxy groups are preferred, and linear alkoxy groups are more preferred. The number of carbon atoms in the alkoxy group generally ranges from C1 to C12, preferably from C1 to C8, more preferably from C1 to C6, and further preferably from C1 to C4. Specific examples of the alkoxy group may include: linear alkoxy groups such as methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy; branched (preferably C3 to C10) alkoxy groups such as isopropoxy, isobutoxy, sec-butoxy, tert-butoxy, isopentyloxy, tert-pentyloxy, isohexyloxy, tert-hexyloxy, isoheptyloxy, tert-heptyloxy, isooctyloxy, tert-octyloxy, 2-ethylhexyloxy, isononyloxy, isodecyloxy; cyclic (preferably C3 to C7) alkoxy groups such as cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, etc.

[0036] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 The aryloxy group in [it] is preferably a C6 to C12 aryloxy group. Specific examples of the aryloxy group may include: phenoxy, naphthyloxy, biphenyloxy, etc.

[0037] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10The alkylcarbonyloxy groups therein may include linear alkylcarbonyloxy groups, branched alkylcarbonyloxy groups or cyclic alkylcarbonyloxy groups. Among them, C1-C10 alkylcarbonyloxy groups are preferred. Specific examples of the alkylcarbonyloxy groups may include: linear alkylcarbonyloxy groups such as methylcarbonyloxy, ethylcarbonyloxy, n-propylcarbonyloxy, n-butylcarbonyloxy, n-pentylcarbonyloxy, n-hexylcarbonyloxy, n-heptylcarbonyloxy, n-octylcarbonyloxy, n-nonylcarbonyloxy, n-decylcarbonyloxy; branched (preferably C3-C10) alkylcarbonyloxy groups such as isopropylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, isopentylcarbonyloxy, tert-pentylcarbonyloxy, isohexylcarbonyloxy, tert-hexylcarbonyloxy, isoheptylcarbonyloxy, tert-heptylcarbonyloxy, isooctylcarbonyloxy, tert-octylcarbonyloxy, 2-ethylhexylcarbonyloxy, isononylcarbonyloxy, isodecylcarbonyloxy; cyclic (preferably C3-C7) alkylcarbonyloxy groups such as cyclopropylcarbonyloxy, cyclobutylcarbonyloxy, cyclopentylcarbonyloxy, cyclohexylcarbonyloxy, cycloheptylcarbonyloxy. Among them, linear alkylcarbonyloxy groups or branched alkylcarbonyloxy groups are preferred, and linear alkylcarbonyloxy groups are more preferred.

[0038] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 Among the arylcarbonyloxy groups therein, C6-C12 arylcarbonyloxy groups are preferred. Specific examples of the arylcarbonyloxy groups may include: phenylcarbonyloxy, naphthylcarbonyloxy, biphenylcarbonyloxy, etc.

[0039] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10The alkylcarbonylamino group in [it] may include linear alkylcarbonylamino group, branched alkylcarbonylamino group or cyclic alkylcarbonylamino group. Among them, C1-C10 alkylcarbonylamino group is preferred. Specific examples of the alkylcarbonylamino group may include: linear alkylcarbonylamino groups such as methylcarbonylamino group, ethylcarbonylamino group, n-propylcarbonylamino group, n-butylcarbonylamino group, n-pentylcarbonylamino group, n-hexylcarbonylamino group, n-heptylcarbonylamino group, n-octylcarbonylamino group, n-nonylcarbonylamino group, n-decylcarbonylamino group; branched (preferably C3-C10) alkylcarbonylamino groups such as isopropylcarbonylamino group, isobutylcarbonylamino group, sec-butylcarbonylamino group, tert-butylcarbonylamino group, isopentylcarbonylamino group, tert-pentylcarbonylamino group, isohexylcarbonylamino group, tert-hexylcarbonylamino group, isoheptylcarbonylamino group, tert-heptylcarbonylamino group, isooctylcarbonylamino group, tert-octylcarbonylamino group, 2-ethylhexylcarbonylamino group, isononylcarbonylamino group, isodecylcarbonylamino group; cyclic (preferably C3-C7) alkylcarbonylamino groups such as cyclopropylcarbonylamino group, cyclobutylcarbonylamino group, cyclopentylcarbonylamino group, cyclohexylcarbonylamino group, cycloheptylcarbonylamino group, etc. Among them, linear alkylcarbonylamino group or branched alkylcarbonylamino group is preferred, and linear alkylcarbonylamino group is more preferred.

[0040] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 For the arylcarbonylamino group in [it], C6-C12 arylcarbonylamino group is preferred. Specific examples of the arylcarbonylamino group may include: phenylcarbonylamino group, naphthylcarbonylamino group, biphenylcarbonylamino group, etc.

[0041] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10The alkylsulfonylamino group in it may include linear alkylsulfonylamino group, branched-chain alkylsulfonylamino group or cyclic alkylsulfonylamino group. Among them, C1-C10 alkylsulfonylamino group is preferred. Specific examples of the alkylsulfonylamino group may include: linear alkylsulfonylamino groups such as methylsulfonylamino group, ethylsulfonylamino group, n-propylsulfonylamino group, n-butylsulfonylamino group, n-pentylsulfonylamino group, n-hexylsulfonylamino group, n-heptylsulfonylamino group, n-octylsulfonylamino group, n-nonylsulfonylamino group, n-decylsulfonylamino group, etc.; branched-chain (preferably C3-C10) alkylsulfonylamino groups such as isopropylsulfonylamino group, isobutylsulfonylamino group, sec-butylsulfonylamino group, tert-butylsulfonylamino group, isopentylsulfonylamino group, tert-pentylsulfonylamino group, isohexylsulfonylamino group, tert-hexylsulfonylamino group, isoheptylsulfonylamino group, tert-heptylsulfonylamino group, isooctylsulfonylamino group, tert-octylsulfonylamino group, 2-ethylhexylsulfonylamino group, isononylsulfonylamino group, isodecylsulfonylamino group, etc.; cyclic (preferably C3-C7) alkylsulfonylamino groups such as cyclopropylsulfonylamino group, cyclobutylsulfonylamino group, cyclopentylsulfonylamino group, cyclohexylsulfonylamino group, cycloheptylsulfonylamino group, etc. Among them, linear alkylsulfonylamino group or branched-chain alkylsulfonylamino group is preferred, and linear alkylsulfonylamino group is more preferred.

[0042] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 Among the arylsulfonylamino groups, C6-C12 arylsulfonylamino group is preferred. Specific examples of the arylsulfonylamino group may include: phenylsulfonylamino group, tolylsulfonylamino group, naphthylsulfonylamino group, biphenylsulfonylamino group, etc.

[0043] In one embodiment of the present invention, as R in the formula (1) 1 ~R 10The monoalkylamino in [it] may include linear monoalkylamino, branched monoalkylamino or cyclic monoalkylamino. Among them, mono C1-C10 alkylamino is preferred. Specific examples of the monoalkylamino may include: linear monoalkylamino such as methylamino, ethylamino, n-propylamino, n-butylamino, n-pentylamino, n-hexylamino, n-heptylamino, n-octylamino, n-nonylamino, n-decylamino, etc.; branched (preferably C3-C10) monoalkylamino such as isopropylamino, isobutylamino, sec-butylamino, tert-butylamino, isopentylamino, tert-pentylamino, isohexylamino, tert-hexylamino, isoheptylamino, tert-heptylamino, isooctylamino, tert-octylamino, 2-ethylhexylamino, isononylamino, isodecylamino, etc.; cyclic (preferably C3-C7) monoalkylamino such as cyclopropylamino, cyclobutylamino, cyclopentylamino, cyclohexylamino, cycloheptylamino, etc. Among them, linear monoalkylamino or branched monoalkylamino is preferred, and linear monoalkylamino is more preferred.

[0044] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 The dialkylamino in [it] may include linear dialkylamino, branched dialkylamino or cyclic dialkylamino. Among them, di C1-C10 alkylamino is preferred. Specific examples of the dialkylamino may include: linear dialkylamino such as dimethylamino, diethylamino, di-n-propylamino, di-n-butylamino, di-n-pentylamino, di-n-hexylamino, di-n-heptylamino, di-n-octylamino, di-n-nonylamino, di-n-decylamino, etc.; branched (preferably having two C3-C10 branches) dialkylamino such as diisopropylamino, diisobutylamino, di-sec-butylamino, di-tert-butylamino, diisopentylamino, di-tert-pentylamino, diisohexylamino, di-tert-hexylamino, diisoheptylamino, di-tert-heptylamino, diisooctylamino, di-tert-octylamino, bis-(2-ethylhexyl)amino, diisononylamino, diisodecylamino, etc.; cyclic (preferably having two C3-C7 cyclic groups) dialkylamino such as dicyclopropylamino, dicyclobutylamino, dicyclopentylamino, dicyclohexylamino, dicycloheptylamino, etc. Among them, linear dialkylamino or branched dialkylamino is preferred, and linear dialkylamino is more preferred.

[0045] In one embodiment of the present invention, as R in the general formula (1) 1 ~R 10 The arylamino in [it] may include: monoarylamino or diarylamino. Among them, mono C6-C12 arylamino is preferred. Specific examples thereof may include: phenylamino (anilino), naphthylamino, biphenylamino, etc. Similarly, as the arylamino, di C6-C12 arylamino may be included. Specific examples thereof may include: diphenylamino, dinaphthylamino, dibiphenylamino, etc.

[0046] In one embodiment of the present invention, the compound represented by the general formula (1) is preferably the compound of the general formula (2) above.

[0047] R in the general formula (2) above 1 ~R 3 is preferably an alkyl group or a hydrogen atom, more preferably a linear C1-C4 alkyl group or a hydrogen atom, and particularly preferably a methyl group or a hydrogen atom.

[0048] In the general formula (1) above, as the substitution position of the substituent represented by the following general formula (3), the ortho position, meta position and para position can be cited, and the para position or meta position is preferred.

[0049]

[0050] As the compounds in the present invention, specific examples in Table 1 below can be cited, but are not limited thereto.

[0051] Table 1-1

[0052]

[0053] Table 1-2

[0054]

[0055] The compound of the general formula (1) of the present invention can be obtained, for example, by a known synthesis method described in European Journal of Medicinal Chemistry (2017), 125, 865-880 (Non-Patent Document 1).

[0056] [Manufacturing Process]

[0057]

[0058] (In the formula, R 1 ~R 10 has the same meaning as above.)

[0059] The compound of the above general formula [1-2] can be produced by reacting the compound of general formula [1-1] with a phenyl isocyanate compound in the presence or absence of a base. As the solvent used in this reaction, there is no particular limitation as long as it has no effect on the reaction. For example, amide compounds such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; halogenated hydrocarbon compounds such as dichloromethane and chloroform; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; ether compounds such as dioxane, tetrahydrofuran, anisole, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, and diethylene glycol diethyl ether; nitrile compounds such as acetonitrile; ketone compounds such as acetone and 2-butanone; ester compounds such as ethyl acetate and butyl acetate; sulfone compounds such as sulfolane; sulfoxide compounds such as dimethyl sulfoxide; water, etc. These substances can be used in combination.

[0060] The amount of the phenyl isocyanate compound used in this reaction is generally 0.1 to 50 times the molar amount, preferably 0.5 to 3 times the molar amount, relative to the compound of general formula [1-1].

[0061] As the base optionally used in this reaction, for example, inorganic bases such as sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, and cesium carbonate; organic bases such as triethylamine and diisopropylethylamine can be cited. The amount of these bases used is 0.1 to 50 times the molar amount, preferably 0.5 to 5 times the molar amount, relative to the compound of general formula [1-1].

[0062] The reaction temperature of this reaction is generally -78°C to 120°C, preferably -10°C to 80°C. The reaction can be carried out for 10 minutes to 24 hours.

[0063] The compound of the above general formula [1-3] can be produced by a method in which a sulfonyl chloride is formed by reacting the compound of general formula [1-2] with phosphoryl chloride, thionyl chloride, chlorosulfonic acid, oxalyl chloride, etc. in the presence or absence of a base, and then reacting it with a phenolic compound, or by a method of directly dehydrating and condensing to react with a phenolic compound.

[0064] As the solvent used in this reaction, there is no particular limitation as long as it has no effect on the reaction. For example, amide compounds such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; halogenated hydrocarbon compounds such as dichloromethane and chloroform; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; ether compounds such as dioxane, tetrahydrofuran, anisole, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, and diethylene glycol diethyl ether; nitrile compounds such as acetonitrile; ketone compounds such as acetone and 2-butanone; ester compounds such as ethyl acetate and butyl acetate; sulfone compounds such as sulfolane; sulfoxide compounds such as dimethyl sulfoxide; water, etc. These substances can be used in combination.

[0065] The amount of the phenolic compound used in this reaction is 0.1 to 50 times the molar amount, preferably 0.7 to 3 times the molar amount, relative to the compound of the general formula [1-2]. The reaction temperature is usually -78°C to 100°C, preferably -20°C to 80°C. The reaction time can be carried out for 10 minutes to 24 hours.

[0066] When forming the thermosensitive recording material of the present invention, the color-forming compound is usually 1% to 50% by mass, preferably 5% to 30% by mass; the compound represented by the above general formula (1) is usually 1% to 70% by mass, preferably 10% to 50% by mass; the sensitizer is 1% to 80% by mass; the storage stability improver is usually 0% to 30% by mass; the binder is usually 1% to 90% by mass; the filler is usually 0% to 80% by mass; other lubricants, surfactants, defoaming agents, and ultraviolet absorbers are each used in an arbitrary proportion, for example, usually each 0% to 30% by mass (the mass% is the mass ratio of each component in the thermosensitive color-forming layer).

[0067] As a more preferred mode, in the above composition, in terms of mass ratio, relative to 1 of the color-forming compound, the compounds represented by the formula (1) are each usually used in the range of 0.5 to 20 times, more preferably 1 to 5 times, the mass ratio. In the thermosensitive recording material of the present invention, in addition to the above components, known color-developing compounds, sensitizers, or other additives can also be used in combination.

[0068] The color-forming compound used in the present invention may be any compound commonly used in pressure-sensitive recording paper and thermosensitive recording paper, and there is no particular limitation. Examples of the color-forming compound used include, for example: fluoran compounds, triarylmethane compounds, spiro compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, fluorene compounds, and fluoran compounds are preferred.

[0069] As specific examples of fluorane compounds, for example, the following can be cited: 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isopentylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isobutylamino)-6-methyl-7-anilinofluoran, 3-[N-ethyl-N-(3-ethoxypropyl)amino]-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-hexylamino)-6-methyl-7-anilinofluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-propylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-tetrahydrofurylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(p-chloroanilino)fluoran, 3-diethylamino-6-methyl-7-(p-fluoroanilino)fluoran, 3-[N-ethyl-N-(p-tolyl)amino]-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(p-toluidino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-diethylamino-7-(o-fluoroanilino)fluoran, 3-dibutylamino-7-(o-fluoroanilino)fluoran, 3-diethylamino-7-(3,4-dichloroanilino)fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7-octylfluoran, 3-[N-ethyl-N-(p-tolyl)amino]-6-methyl-7-phenethylfluoran, etc. Among them, 3-dibutylamino-6-methyl-7-anilinofluoran is preferred.

[0070] As specific examples of triarylmethane compounds, for example, the following can be cited: 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (alias: crystal violet lactone or CVL), 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2-dimethylaminoindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-phenylindol-3-yl)phthalide, 3,3-bis(1,2-dimethylindol-3-yl)-5-dimethylaminophthalide, 3,3-bis(1,2-dimethylindol-3-yl)-6-dimethylaminophthalide, 3,3-bis(9-ethylcarbazol-3-yl)-5-dimethylaminophthalide, 3,3-(2-phenylindol-3-yl)-5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide, and the like.

[0071] As specific examples of spiro compounds, for example, the following can be cited: 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho-(3-methoxybenzene)spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro(indoline-2,2'-benzopyran), and the like; as specific examples of diphenylmethane compounds, for example, the following can be cited: N-halophenylleucoauramine, 4,4-bis(dimethylaminophenyl)diphenylmethyl benzyl ether, N-2,4,5-trichlorophenylleucoauramine, and the like; as specific examples of thiazine compounds, for example, the following can be cited: benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue, and the like; as specific examples of lactam compounds, for example, the following can be cited: rhodamine B anilide, rhodamine B-p-chloroanilide, and the like; as specific examples of fluorene compounds, for example, the following can be cited: 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-dimethylaminophthalide, 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-pyrrolidinylphthalide, 3-dimethylamino-6-diethylamino fluorene spiro(9,3')-6'-pyrrolidinylphthalide, and the like. These chromogenic compounds can be used alone or in combination.

[0072] As the color-developing compound that can be used in combination in the present invention, there is no particular limitation as long as it is a compound commonly used in pressure-sensitive recording paper and thermal recording paper. For example, it can include: α-naphthol, β-naphthol, p-octylphenol, 4-tert-octylphenol, p-tert-butylphenol, p-phenylphenol, 1,1-bis(p-hydroxyphenyl)propane, 2,2-bis(p-hydroxyphenyl)propane (also known as bisphenol A or BPA), 2,2-bis(p-hydroxyphenyl)butane, 1,1-bis(p-hydroxyphenyl)cyclohexane, 4,4'-thiobisphenol, 4,4'-cyclohexylidenediphenol, 2,2'-bis(2,5-dibromo-4-hydroxyphenyl)propane, 4,4'-isopropylidene bis(2-tert-butylphenol), 2,2'-methylenebis(4-chlorophenol), 4,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methoxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-4'-ethoxydiphenyl sulfone, 4-hydroxy-4'-butoxydiphenyl sulfone, 4-hydroxy-4'-benzyloxydiphenyl sulfone, methyl bis(4-hydroxyphenyl)acetate, butyl bis(4-hydroxyphenyl)acetate, benzyl bis(4-hydroxyphenyl)acetate, phenolic compounds such as 2,4-dihydroxy-2'-methoxybenzoylaniline; benzyl p-hydroxybenzoate, ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-tert-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid and other aromatic carboxylic acid derivatives, aromatic carboxylic acids; or their polyvalent metal salts, etc.

[0073] Specific examples of the sensitizer (thermofusible compound) used in the present invention include, for example: waxes such as animal and vegetable waxes, synthetic waxes; higher fatty acids, higher fatty acid amides, higher fatty acid anilides, naphthalene derivatives, aromatic ethers, aromatic carboxylic acid derivatives, aromatic sulfonate derivatives, carbonic acid or oxalic acid diester derivatives, biphenyl derivatives, terphenyl derivatives, sulfone derivatives, aromatic ketone derivatives, aromatic hydrocarbon compounds, etc.

[0074] As specific examples of waxes, for example, the following can be cited: wood wax, carnauba wax, shellac, paraffin wax, lignite wax, oxidized paraffin wax, polyethylene wax, oxidized polyethylene wax, etc.; as higher fatty acids, for example, the following can be cited: stearic acid, behenic acid, etc.; as higher fatty acid amides, for example, the following can be cited: stearamide, oleamide, N-methylstearamide, erucamide, hydroxymethyl behenamide, methylene bisstearamide, ethylene bisstearamide, etc.; as higher fatty acid anilides, for example, the following can be cited: stearylanilide, linoleylanilide, etc.; as naphthalene derivatives, for example, the following can be cited: 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, phenyl 1-hydroxynaphthoate, 2,6-diisopropylnaphthalene, etc.; as aromatic ethers, for example, the following can be cited: 1,2-diphenoxyethane, 1,4-diphenoxybutane, 1,2-bis(3-methylphenoxy)ethane, 1,2-bis(4-methoxyphenoxy)ethane, 1,2-bis(3,4-dimethylphenyl)ethane, 1-phenoxy-2-(4-chlorophenoxy)ethane, 1-phenoxy-2-(4-methoxyphenoxy)ethane, 1,2-diphenoxymethylbenzene, diphenyl glycol ether, etc.; as aromatic carboxylic acid derivatives, for example, the following can be cited: benzyl p-hydroxybenzoate, benzyl p-benzyloxybenzoate, dibenzyl terephthalate, etc.; as aromatic sulfonate derivatives, for example, the following can be cited: phenyl p-toluenesulfonate, phenyl mesitylenesulfonate, 4-methylphenyl mesitylenesulfonate, 4-tolyl mesitylenesulfonate, etc.; as carbonic acid or oxalic acid diester derivatives, for example, the following can be cited: diphenyl carbonate, dibenzyl oxalate, bis(4-chlorobenzyl) oxalate, bis(4-methylbenzyl) oxalate, etc.; as biphenyl derivatives, for example, the following can be cited: p-benzylbiphenyl, p-allyloxybiphenyl, etc.; as terphenyl derivatives, for example, the following can be cited: m-terphenyl, etc.; as sulfone derivatives, for example, the following can be cited: p-toluenesulfonamide, phenylsulfonanilide, p-toluenesulfonanilide, 4,4-diallyloxydiphenyl sulfone, diphenyl sulfone, etc.; as aromatic ketone derivatives, for example, the following can be cited: 4,4-dimethyldiphenyl ketone, dibenzoylmethane, etc.; as aromatic hydrocarbon compounds, for example, the following can be cited: p-acetotoluidide, etc.

[0075] Specific examples of the preservative improver used in the present invention include, for example: 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 2,2'-ethylidenebis(4,6-di-tert-butylphenol), 4,4'-thiobis(2-methyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-m-cresol), 1-[α-methyl-α-(4'-hydroxyphenyl)ethyl]-4-[α',α'-bis(4'-hydroxyphenyl)ethyl]benzene, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, tris(2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl)isocyanurate, 4,4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3',5,5'-tetramethyldiphenyl sulfone, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane and other hindered phenol compounds; 1,4-diglycidoxybenzene, 4,4'-diglycidoxydiphenyl sulfone, 4-benzyloxy-4'-(2-methyloxiranylmethoxy)diphenyl sulfone, diglycidyl terephthalate, cresol novolak type epoxy resin, phenol novolak type epoxy resin, bisphenol A type epoxy resin and other epoxy compounds; N,N'-di(2-naphthyl)-p-phenylenediamine, sodium salt or polyvalent metal salt of 2,2'-methylenebis(4,6-di-tert-butylphenyl) phosphate, bis(4-ethyleneiminocarbonylaminophenyl)methane, urethane carbamate compound (such as the developer UU manufactured by Chemipro Kasei Co., Ltd.) and the diphenyl sulfone crosslinked type compound represented by the following formula (4) or a mixture thereof, etc.

[0076]

[0077] (In formula (4), a is an integer from 0 to 6.)

[0078] Specific examples of the binder used in the present invention include, for example: methyl cellulose, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), carboxyl-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, silyl group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin, water-soluble isoprene rubber, alkali metal salts of styrene-maleic anhydride copolymers, alkali metal salts of isobutene (or diisobutene)-maleic anhydride copolymers, etc. water-soluble polymers; or (meth)acrylate copolymers, styrene-(meth)acrylate copolymers, polyurethanes, polyester-type polyurethanes, polyether-type polyurethanes, polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyvinylidene chloride, polystyrene, styrene-butadiene (SB) copolymers, carboxylated styrene-butadiene (SB) copolymers, styrene-butadiene-acrylic copolymers, acrylonitrile-butadiene (NB) copolymers, carboxylated acrylonitrile-butadiene (NB) copolymers, composite particles of colloidal silica and (meth)acrylic resins, etc. hydrophobic polymers. These substances are usually utilized in the form of emulsions.

[0079] Specific examples of the filler used in the present invention include, for example: calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon black, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, alumina, barium sulfate, polystyrene resin, urea-formaldehyde resin, etc.

[0080] In addition, in the present invention, various additives other than those described above can be used. For example, there can be mentioned: higher fatty acid metal salts such as zinc stearate and calcium stearate for the purpose of preventing wear of the thermal head, preventing adhesion, etc.; ultraviolet absorbers such as phenolic derivatives, benzophenone compounds, benzotriazole compounds, etc. for imparting antioxidant or anti-aging effects; or various surfactants, defoaming agents, etc.

[0081] Next, the method for preparing the thermal recording material and the thermal recording sheet of the present invention will be described. Using a disperser such as a ball mill, a grinder, a sand mill, etc., the color-forming compound used in the present invention and the compound represented by the above general formula (1) are separately pulverized and dispersed together with a binder or other additives as needed (usually when performing wet pulverization and dispersion, water is used as the medium), and then the dispersions are mixed to prepare a thermal recording material coating solution, which is applied onto a support such as paper (ordinary paper, high-quality paper, coated paper, etc.), a plastic sheet, a synthetic paper, etc. using a bar coater, a knife coater, etc. so that it usually reaches 1 g / m 2 ~20 g / m 2It is coated in such a way and dried to form a thermosensitive recording layer, thereby producing a thermosensitive recording sheet.

[0082] In addition, an intermediate layer can be provided between the thermosensitive recording layer and the support as needed, or an overcoat layer (protective layer) can be provided on the thermosensitive recording layer. The intermediate layer and the overcoat layer (protective layer) can be formed, for example, in the following manner: together with the above-mentioned binder or other additives as needed, they are pulverized and dispersed as needed in the same manner as in the preparation of the thermosensitive recording material coating solution to prepare a coating solution for the intermediate layer or a coating solution for the overcoat layer (protective layer), and then coated in such a way that it generally reaches about 0.1 g / m 2 ~about 10 g / m 2 and dried.

[0083] Examples

[0084] Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples. In the examples, "parts" are parts by mass, and "%" in the solution description is mass %.

[0085] [Synthesis Example 1] Synthesis of Compound No. 2 in Table 1 (refer to Non-Patent Document 1)

[0086]

[0087] 100.0 parts of 3-aminobenzenesulfonic acid [2-1] (Tokyo Chemical Industry Co., Ltd.) was added to 100 parts of DMF and stirred, and then 69 parts of phenyl isocyanate (Tokyo Chemical Industry Co., Ltd.) was added dropwise at room temperature. Stirring was carried out at the same temperature for 4 hours, and then the crystals were precipitated by dropping the reaction solution into 250 parts of water to obtain [2-2]. Then, 90 parts of phosphoryl chloride (Tokyo Chemical Industry Co., Ltd.) was added dropwise at 0 °C, and stirring was carried out at room temperature for 12 hours. Then, 60 parts of phenol (Tokyo Chemical Industry Co., Ltd.) was added dropwise at room temperature, 80 parts of potassium carbonate was slowly added, and stirring was carried out at room temperature for 12 hours. Then, the crystals were precipitated by dropping the reaction solution into 200 parts of water, and then washed successively with dichloromethane and water and dried, whereby 200 parts of Compound No. 2 in Table 1 was obtained in the form of a white solid.

[0088] MS(ESI): [M-H] - : Calculated value: 381.4, Measured value: 381.4.

[0089] [Example 1] Preparation of Thermosensitive Recording Material

[0090] Using the multi-bead oscillator (model: PV1001(S)) manufactured by Anjing Instruments Co., Ltd., the compound No. 2 listed in Table 1 obtained in Synthesis Example 1 was pulverized and dispersed for 1 hour according to the following composition to prepare Solution [A].

[0091] Table 2

[0092] [A] solution: 15 parts of compound No. 2 listed in Table 1

[0093] 20 parts of 25% PVA aqueous solution

[0094] 65 parts of water

[0095] The mixture with the following composition was pulverized and dispersed using a sand mill so that the median particle size measured by the laser diffraction / scattering particle size distribution measuring device LA-950 (Horiba, Ltd.) reached 1 μm, thereby preparing a dispersion liquid [B] of the chromogenic compound.

[0096] Table 3

[0097] [B] solution: 35 parts of 3-dibutylamino-6-methyl-7-anilinofluoran

[0098] 40 parts of 15% PVA aqueous solution

[0099] 25 parts of water

[0100] Next, each of the above-obtained liquids and the following reagents were mixed according to the following composition to prepare a thermal recording material coating solution, so that the mass during drying reached 5 g / m 2 The coating solution was coated on a high-grade paper with a basis weight of 50 g / m 2 and dried to form a thermal recording layer.

[0101] Table 4

[0102]

[0103] (Formation of protective layer)

[0104] Next, the protective layer coating solution containing the following composition was coated on the above thermal recording layer so that the mass during drying reached 2 g / m 2 and dried to produce a thermal recording paper with a protective layer.

[0105] Table 5

[0106]

[0107] [Comparative Example 1]

[0108] Using a sand mill to pulverize and disperse a mixture having the following composition so that the median particle size measured by a laser diffraction / scattering particle size distribution measuring device LA-950 (manufactured by Horiba, Ltd.) reaches 1 μm, thereby preparing [C] liquid. Using [C] liquid to replace [A] liquid in the composition of the thermosensitive recording layer coating liquid described in Example 1 above, and mixing with the following composition ratio, thereby preparing a thermosensitive recording material coating liquid. Except for this, a comparative thermosensitive recording paper with a protective layer was obtained in the same manner as in Example 1.

[0109] Table 6

[0110] [C] liquid: 25 parts of bisphenol S (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0111] 20 parts of 25% PVA aqueous solution

[0112] 55 parts of water

[0113] [Water resistance evaluation test]

[0114] Using a thermosensitive printer (TH-M2 / PP) manufactured by Okura Engineering Co., Ltd. to print on the thermosensitive recording papers obtained in Example 1 and Comparative Example 1 with a pulse width of 1.2 milliseconds, and immersing the specimens in water at 25°C for 24 hours. Using a colorimeter manufactured by Gretag-Macbeth, trade name "SpectroEye", to measure the Macbeth reflection density of the colored parts of the specimens before and after the test. When performing colorimetry, it was carried out under the conditions of illuminant C as the light source, ANSI A as the density standard, and a viewing angle of 2 degrees. The results are shown in Table 7 below. It should be noted that the higher the residual rate, the more excellent the water resistance. The residual rate is calculated by the following formula (I).

[0115] Residual rate (%) = (Macbeth reflection density of the colored part of the specimen after the test) / (Macbeth reflection density of the colored part of the specimen before the test) × 100 (I)

[0116] Table 7

[0117] Water resistance test Example 1 Comparative Example 1 Residual rate (%) 100 76

[0118] As can be seen from Table 7 above, compared with Comparative Example 1 using bisphenol S described as a color-developing compound in Patent Document 2, the residual rate of Example 1 using the compound of the present invention as a color-developing compound is higher. It can be said that compared with the prior art, the water resistance of the colored part of the present invention is more excellent.

[0119] [Evaluation test of the heat resistance of the background]

[0120] Using a forced-air constant temperature thermostat manufactured by Yamato Scientific Co., Ltd., trade name DKN402, the thermal recording paper obtained in Example 1 and Comparative Example 1 was held at 90°C for 1 hour. The ISO whiteness of the background before and after the test was measured using a colorimeter manufactured by Gretag-Macbeth Co., Ltd., trade name SpectroEye. When measuring the color, it was carried out under the conditions that the light source was illuminant C, the concentration standard was ANSI A, and the viewing angle was 2 degrees. The results are shown in Table 8. It should be noted that the smaller the change amount of the ISO whiteness before and after the test, the more excellent the heat resistance of the background.

[0121] Table 8

[0122]

[0123] As can be seen from Table 8 above, in Example 1 using the color-developing compound of the present invention, since the change amount of the ISO whiteness before and after the heat resistance test was small, the heat resistance of the background was more excellent than that of Comparative Example 1 using bisphenol S described in Patent Document 2 as the color-developing compound.

Claims

1. A heat-sensitive recording material, wherein, The thermosensitive recording material contains a compound represented by the following general formula (1). In formula (1), R 1 ~R 10 each independently represents a hydrogen atom, a halogen atom, a nitro group, an amino group, an alkyl group, a hydroxyl group, an alkoxy group, an aryloxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkylcarbonylamino group, an arylcarbonylamino group, an alkylsulfonylamino group, an arylsulfonylamino group, a monoalkylamino group, a dialkylamino group or an arylamino group.

2. The heat-sensitive recording material according to claim 1, wherein, The compound represented by the general formula (1) is a compound represented by the following general formula (2). In formula (2), R 1 ~R 3 has the same meaning as described above.

3. The heat-sensitive recording material according to claim 2, wherein, In general formula (2), R 1 ~R 3 are each independently a hydrogen atom or a methyl group.

4. A heat-sensitive recording layer, wherein, The thermosensitive recording layer contains the thermosensitive recording material according to any one of claims 1 to 3.

5. A heat-sensitive recording paper, wherein, The thermosensitive recording paper contains the thermosensitive recording layer according to claim 4.

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