Thermal recording device

Abstract

To provide a thermosensitive recording body having excellent solvent immersion resistance.SOLUTION: There is provided a thermosensitive recording body having a thermosensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting color developer on a support, wherein the thermosensitive recording layer contains an iron stearate salt and a polyhydric hydroxyaromatic compound as a metal chelate-type coloring component and at least one urea compound represented by the following general formula: (wherein, Y represents -O- or -NH-, R1 represents a hydrogen atom or -SO2-R3, R3 represents a substituted or unsubstituted alkyl group, an aralkyl group or an aryl group, R2 represents a hydrogen tom or an alkyl group, m represents an integer of 0 to 2 and n represents 0 to 1.) as an electron-accepting color developer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a thermal recording material with excellent solvent resistance. [Background technology]

[0002] A thermal recording medium generally has a thermal recording layer consisting of a colorless or pale electron-donating leuco dye (hereinafter sometimes simply referred to as "leuco dye") and an electron-accepting developer (hereinafter sometimes simply referred to as "developer"; the color-developing component containing these leuco dyes and developers is also simply called a "leuco dye-type color-developing component"), a binder, a filler, a sensitivity enhancer, a lubricant, and other auxiliary agents, and is an information recording medium that obtains recorded information (color-developed information) by heat from a thermal head, hot stamp, thermal pen, laser light, etc. Thermal recording media are used in a wide range of applications, including measuring recorders, computer terminal printers, fax machines, automatic ticket vending machines, and barcode labels. However, with the diversification and increased performance of recording devices, the required quality of thermal recording media has also become more stringent. For example, with the increase in recording speed, it is necessary to obtain high-density and clear recorded information even with minute amounts of thermal energy. At the same time, thermal recording media with excellent preservation properties such as light resistance, heat resistance, water resistance, oil resistance, and plasticizer resistance are required. Furthermore, the use of adding additional information to the opposite side (back side) of the thermal recording layer with stamps or pens has also expanded. Furthermore, thermal recording media that utilize the color reaction between leuco dyes and color developers have the problem that the recorded information fades over time. To address this problem of faded recorded information, thermal recording media containing a metal chelate-type color component consisting of an electron donor and an electron acceptor have been disclosed (Patent Documents 1 and 2). Furthermore, by using a combination of two specific color developers, thermal recording materials with improved water resistance, plasticizer resistance in the image area, and heat resistance in the blank area have been disclosed (Patent Document 3, etc.), as well as urea compounds as color developers to improve the required performance of thermal recording materials, such as color density, whiteness, preservation of the printed area, and oil resistance (Patent Documents 4, 5, etc.). [Prior art documents]

Patent Document

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] ]]<![CDATA[ ]]An object of the present invention is to provide a heat-sensitive recording medium having excellent solvent immersion resistance. <![CDATA[ ]]Here, the solvent immersion resistance refers to the property that even when the heat-sensitive recording medium is immersed in a solvent such as alcohol, a decrease in the printing density of the printed portion is suppressed. For example, in a work site where a large amount of organic solvent is used or in a medical site where strict alcohol disinfection is performed, there are advantages such as the heat-sensitive recording medium can be effectively used and stored. <![CDATA[ ]]

Means for Solving the Problems

[0005] ]]<![CDATA[ ]]As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by containing a specific urea compound as a developer in a coloring system containing a leuco dye type coloring component and a metal chelate type coloring component, and have completed the present invention. <![CDATA[ ]]<![CDATA[

[0006] ]]<![CDATA[ ]]That is, the present invention relates to a heat-sensitive recording medium having a heat-sensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, wherein the heat-sensitive recording layer contains iron stearate as a metal chelate type coloring component and the following general formula (Chemical Formula 1) <![CDATA[ ]]<![CDATA[ ]]

Chemical Formula

[0007] The thermal recording body of the present invention is a thermal recording body having a thermal recording layer on a support, and a protective layer may be provided on the thermal recording layer, an undercoat layer between the support and the thermal recording layer, a backcoat layer on the side of the support opposite to the thermal recording layer, and so on. The thermal recording layer of the present invention mainly contains a colorless or pale electron-donating leuco dye and an electron-accepting developer (all leuco dye type color-developing components), and further contains a metal chelate type color-developing component mainly containing an electron acceptor and an electron donor.

[0008] In the thermal recording medium of the present invention, among the metal chelate type coloring components used in the thermal recording layer, as the higher fatty acid metal salt contained as an electron acceptor, iron stearate is used. Compared with other higher fatty acid metal salts generally used as the electron acceptor of the metal chelate type coloring component, in the case of the present invention using iron stearate, there are advantages such as excellent heat resistance and yellowing resistance of the non-printing part.

[0009] In the thermal recording medium of the present invention, among the metal chelate type coloring components used in the thermal recording layer, the polyhydric hydroxyaromatic compound contained as an electron donor is represented by the following general formula (Chemical Formula 1).

Chemical Formula

Chemical Formula

[0010] In the thermal recording medium of the present invention, when preparing a coating solution by dispersing a polyhydric hydroxyaromatic compound, in other words, a polyhydric phenol derivative, which is contained as an electron donor in the thermal recording layer, in an aqueous or solvent-based binder, it is necessary to avoid reacting with an electron acceptor or to enhance solvent resistance and dispersion stability. Therefore, it is desirable to increase the number of carbon atoms of the substituents other than the coloring functional group to 18 to 35. Also, the number of hydroxyl groups is 2 or 3, and it is desirable that each hydroxyl group is adjacent to each other. Specifically, the following can be exemplified, but it is not limited thereto. Also, these polyhydric phenols can be used alone or in combination of two or more as needed. In the following formula, R, R a and Rb It is defined in the same way as above.

[0011] [ka]

[0012] [ka]

[0013] [ka]

[0014] The thermal recording material of the present invention has a thermal recording layer that contains at least one urea compound represented by the following general formula (Chemical Formula 3) as a color developer. [ka] (In the formula, Y, R 1 ~R 3 m and n are as described above and will be explained in detail below. In the above general formula (Chemical Formula 3), R 3 Preferably, it is a substituted or unsubstituted aryl group, and more preferably a group represented by the following formula. [ka] (In the formula, R 4 ~R 8 These may be the same or different, and each represents a hydrogen atom, halogen atom, nitro group, amino group, alkyl group, alkoxy group, aryloxy group, alkylcarbonyloxy group, arylcarbonyloxy group, alkylcarbonylamino group, arylcarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, monoalkylamino group, dialkylamino group, or arylamino group.

[0015] The urea compound is preferably selected from the following (1) to (3). (1) The first urea compound represented by the following general formula (Chemical Formula 4), [ka] (In the formula, R 1 , R 2 and R 3 (This is defined in the same way as above.) (2) A second urea compound represented by the following general formula (Chemical Formula 5), [ka] (In the formula, R 2 And m are defined in the same way as above, R 4 ~R 8 (This will be explained later.) (3) A third urea compound represented by the following formula (Chemical Formula 6) [ka] (In the formula, R 2 It is defined in the same way as above, R 4 ~R 8 (This will be explained later.)

[0016] Furthermore, it is more preferable that the urea compounds used in the present invention are at least two selected from the urea compounds represented by (1) to (3) above. However, in this case, the urea compounds are not selected from more than two from each of (1), (2), or (3). That is, these at least two urea compounds are a combination of the first urea compound and the second urea compound, a combination of the first urea compound and the third urea compound, a combination of the second urea compound and the third urea compound, and a combination of the first to third urea compounds represented by (1) to (3).

[0017] The first urea compound used in the present invention is represented by the following formula (Chemical Formula 4), and preferably by the following formula (Chemical Formula 7). [ka] [ka]

[0018] In the general formula (Chemical formula 4), R 1 is a hydrogen atom or -SO2-R 3 This represents n, where n represents 0 or 1, preferably 1. In general formula (Chemical Formula 4) and general formula (Chemical Formula 7), R 3 R represents an alkyl group, aralkyl group, or aryl group, which may be substituted or unsubstituted. This alkyl group is, for example, a linear, branched, or alicyclic alkyl group, and preferably has 1 to 12 carbon atoms. This aralkyl group preferably has 7 to 12 carbon atoms, and this aryl group preferably has 6 to 12 carbon atoms. Furthermore, if these are substituted, the substituent is preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. Also, multiple R 3 They may be the same or different. R in the benzene ring of general formula (Chemical Formula 4) 1 The position of -O- may be the same or different, and is preferably the 3rd, 4th, or 5th position. R in the benzene ring of general formula (Chemical Formula 4) and general formula (Chemical Formula 7) 3 The position of -SO3-O- may be the same or different, preferably at position 3, 4, or 5.

[0019] Examples of alkyl groups include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, cyclopentyl group, hexyl group, cyclohexyl group, 2-ethylhexyl group, and lauryl group.

[0020] Examples of aralkyl groups include unsubstituted groups such as benzyl group, 1-phenylethyl group, 2-phenylethyl group, 3-phenylpropyl group, p-methylbenzyl group, m-methylbenzyl group, m-ethylbenzyl group, p-ethylbenzyl group, pi-propylbenzyl group, pt-butylbenzyl group, p-methoxybenzyl group, m-methoxybenzyl group, o-methoxybenzyl group, m,p-di-methoxybenzyl group, p-ethoxy-m-methoxybenzyl group, p-phenylmethylbenzyl group, p-cumylbenzyl group, p-phenylbenzyl group, o-phenylbenzyl group, m-phenylbenzyl group, p-tolylbenzyl group, m-tolylbenzyl group, o-tolylbenzyl group, and p-chlorobenzyl group, or aralkyl groups substituted with alkyl groups, alkoxy groups, aralkyl groups, aryl groups, or halogen atoms.

[0021] Examples of aryl groups include unsubstituted groups such as phenyl group, p-tolyl group, m-tolyl group, o-tolyl group, 2,5-dimethylphenyl group, 2,4-dimethylphenyl group, 3,5-dimethylphenyl group, 2,3-dimethylphenyl group, 3,4-dimethylphenyl group, mesitylene group, p-ethylphenyl group, pi-propylphenyl group, pt-butylphenyl group, p-methoxyphenyl group, 3,4-dimethoxyphenyl group, p-ethoxyphenyl group, p-chlorophenyl group, 1-naphthyl group, 2-naphthyl group, and t-butylated naphthyl group, or aryl groups substituted with alkyl groups, alkoxy groups, aralkyl groups, aryl groups, or halogen atoms.

[0022] R 2 represents a hydrogen atom or an alkyl group, preferably a hydrogen atom. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, such as a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, etc. R in the benzene ring of general formula (Chemical Formula 4) 2 The position may be the same or different, and is preferably the 3rd, 4th, or 5th position.

[0023] As the first urea compound of the present invention, a urea compound represented by the following general formula (Chemical Formula 8) is even more preferred. [ka] In the general formula (Chemical formula 8), R 9 is an alkyl group or alkoxy group, preferably an alkyl group, and o represents an integer from 0 to 3, preferably 0 to 2, more preferably 0 to 1. The number of carbon atoms in this alkyl group is, for example, 1 to 12, preferably 1 to 8, more preferably 1 to 4. R in the benzene ring of general formula (Chemical Formula 8) 9 The position may be the same or different, preferably the 3rd, 4th, or 5th position, and preferably the 4th position.

[0024] Furthermore, as the first urea compound of the present invention, for example, N,N'-di-[3-(benzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-methylphenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-ethylphenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-5-methylphenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-propylphenyl]urea, N,N'-di-[3-(o-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-toluenesulfonyloxy)-4-methylphenyl]urea, N,N'-di-[3-(p-xylenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-xylenesulfonyloxy)phenyl]urea, N,N'-di-[3-(mesitylenesulfonyloxy)phenyl]urea, N,N'-di-[3-(1-naphthalenesulfonyloxy)phenyl]urea, N, N'-di-[3-(2-naphthalenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-propylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-isopropylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(pt-butylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-methoxybenzenesulfonyloxy)phenyl]urea [phenyloxy)phenyl]urea, N,N'-di-[3-(o-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-propoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-butoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-cumylbenzylsulfonyloxy)phenyl]urea, N,Examples include, but are not limited to, N'-di-[3-(p-cumylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(o-phenylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-phenylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-chlorobenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(benzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-toluenesulfonyloxy)phenyl]urea, N,N'-di-[3-(ethanesulfonyloxy)phenyl]urea, and N,N'-di-[3-(benzylsulfonyloxy)phenyl]urea.

[0025] The second urea compound used in the present invention is represented by the following formula (Chemical Formula 5). [ka]

[0026] In the general formula (Chemical formula 5), ​​R 2 , R 4 ~R 8 R is defined in the same way as above. In the general formula (Chemical Formula 5), ​​R 4 ~R 8 R is preferably a hydrogen atom, an alkyl group, or an alkoxy group. In particular, 4 , R 5 , R 7 , R 8 Hydrogen atoms are preferred, R 6 A hydrogen atom or an alkyl group is preferred. 6 Alkyl alkyl groups are particularly preferred. These alkyl groups (including alkylcarbonyloxy groups, alkylcarbonylamino groups, alkylsulfonylamino groups, monoalkylamino groups, and dialkylamino groups) and aryl groups (including aryloxy groups, arylcarbonyloxy groups, arylcarbonylamino groups, arylsulfonylamino groups, and arylamino groups) are defined in the same way as the alkyl and aryl groups in the general formula (Chemical Formula 4) above. This alkoxy group is, for example, a linear, branched, or alicyclic alkoxy group, and preferably has 1 to 12 carbon atoms. -O-(CONH) in the benzene ring of general formula (Chemical Formula 5) m The position of the -SO2-substituted phenyl group is preferably at the 3rd, 4th, or 5th position (the same applies to general formulas (Chemical Formula 9) and (Chemical Formula 10) below). In the general formula (Chemical Formula 5), ​​m represents an integer between 0 and 2, preferably between 0 and 1.

[0027] As the second urea compound of the present invention, a urea compound represented by the following general formula (Chemical Formula 9) or the following general formula (Chemical Formula 10) is preferred. [ka] [ka]

[0028] The third urea compound used in the present invention is represented by the following formula (Chemical Formula 6). [ka] In the general formula (chemical formula 6), R 2 , R 4 ~R 8 It is defined in the same way as above.

[0029] The third urea compound is preferably N-[2-(3-phenylureido)phenyl]benzenesulfonamide, which is represented by the following formula and is available, for example, from Nippon Soda Co., Ltd. under the trade name NKK1304. [ka]

[0030] The thermal recording layer of the present invention may use color developers other than the first to third urea compounds described above. Examples of such color developers include inorganic acidic substances such as activated clay, attapulgite, colloidal silica, and aluminum silicate, as well as 4,4'-isopropylidenediphenol, 1,1-bis(4-hydroxyphenyl)cyclohexane, 2,2-bis(4-hydroxyphenyl)-4-methylpentane, 4,4'-dihydroxydiphenyl sulfide, hydroquinone monobenzyl ether, and 4-hydroxybenzoic acid. Benzyl, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-n-propoxydiphenylsulfone, bis(3-allyl-4-hydroxyphenyl)sulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 3,4-dihydroxyphenyl-4'-methylphenylsulfone, 1-[4-(4-Hyd [(4-(4-isopropoxyphenylsulfonyl)phenoxy]-4-[4-(4-isopropoxyphenylsulfonyl)phenoxy]butane, phenol condensation composition described in Japanese Patent Publication No. 2003-154760, aminobenzenesulfonamide derivative described in Japanese Patent Publication No. Hei 8-59603, bis(4-hydroxyphenylthioethoxy)methane, 1,5-di(4-hydroxyphenylthio)-3-oxapentane, bis(p-hydroxyphenyl)butyl acetate, bis(p-hydroxyphenyl)methyl acetate, 1,1-bis( 4-Hydroxyphenyl)-1-phenylethane, 1,4-bis[α-methyl-α-(4'-hydroxyphenyl)ethyl]benzene, 1,3-bis[α-methyl-α-(4'-hydroxyphenyl)ethyl]benzene, di(4-hydroxy-3-methylphenyl) sulfide, 2,2'-thiobis(3-tert-octylphenol), 2,2'-thiobis(4-tert-octylphenol), compounds described in WO02 / 081229 or Japanese Patent Publication No. 2002-301873, and N,Examples include thiourea compounds such as N'-di-m-chlorophenylthiourea, p-chlorobenzoic acid, stearyl gallate, bis[4-(n-octyloxycarbonylamino)zinc salicylate]dihydrate, 4-[2-(p-methoxyphenoxy)ethyloxy]salicylic acid, 4-[3-(p-tolylsulfonyl)propyloxy]salicylic acid, and 5-[p-(2-p-methoxyphenoxyethoxy)cumyl]salicylic acid, as well as salts of these aromatic carboxylic acids with polyvalent metal salts such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, and nickel, and also antipyrine complexes of zinc thiocyanate and complex zinc salts of terephthalaldehyde and other aromatic carboxylic acids. These color developers can be used individually or in mixtures of two or more. 1-[4-(4-hydroxyphenylsulfonyl)phenoxy]-4-[4-(4-isopropoxyphenylsulfonyl)phenoxy]butane is available, for example, as product name JKY-214 from API Corporation, and the phenol condensation composition described in Japanese Patent Publication No. 2003-154760 is available, for example, as product name JKY-224 from API Corporation. Furthermore, compounds described in WO02 / 081229, etc., are available as product names NKK-395 and D-100 from Nippon Soda Co., Ltd. In addition, metal chelate-type coloring components such as higher fatty acid metal double salts and polyvalent hydroxyaromatic compounds described in Japanese Patent Publication No. 10-258577 can also be included.

[0031] When the thermal recording layer of the present invention contains a color developer other than the first to third urea compounds, the total content (solid content) of the first to third urea compounds used relative to the total color developer (including the first to third urea compounds) contained in the thermal recording layer is preferably 50% by weight or more, more preferably 80% by weight or more, and even more preferably 90% by weight or more.

[0032] All electron-donating leuco dyes known in the field of conventional pressure-sensitive or thermal recording paper can be used as electron-donating leuco dyes in the present invention and are not particularly limited, but triphenylmethane compounds, fluorane compounds, fluorene compounds, divinyl compounds, etc. are preferred. Specific examples of typical colorless or light-colored leuco dyes (dye precursors) are shown below. These dye precursors may be used individually or in combination of two or more.

[0033] <Triphenylmethane-based leuco dyes> 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)

[0034] <Fluorane-based leuco dyes> 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)fluorane; 3-Diethylamino-6-methyl-7-(o-fluoroanilino)fluorane; 3-Diethylamino-6-methyl-7-(m-methylanilino)fluorane; 3-Diethylamino-6-methyl-7-n-octylanilinofluorane; 3-Diethylamino-6-methyl-7-n-octylaminofluorane; 3-Diethylamino-6-methyl-7-benzylaminofluorane; 3-Diethylamino-6-methyl-7-dibenzyaminofluorane; 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-ethoxyethyl-7-anilinofluorane; 3-Dibutylamino-6-chloro-7-anilinofluorane; 3-Dibutylamino-6-methyl-7-p-methylanilinofluorane; 3-Dibutylamino-7-(o-chloroanilino)fluorane; 3-Dibutylamino-7-(o-fluoroanilino)fluorane; 3-Di-n-pentylamino-6-methyl-7-anilinofluorane; 3-Di-n-pentylamino-6-methyl-7-(p-chloroanilino)fluorane; 3-Di-n-pentylamino-7-(m-trifluoromethylanilino)fluorane; 3-di-n-pentylamino-6-chloro-7-anilinofluorane; 3-di-n-pentylamino-7-(p-chloroanilino)fluorane; 3-pyrrolidino-6-methyl-7-anilinofluorane; 3-piperidino-6-methyl-7-anilinofluorane; 3-(N-methyl-N-propylamino)-6-methyl-7-anilinofluorane; 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane; 3-(N-ethyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane; 3-(N-ethyl-N-xylamino)-6-methyl-7-(p-chloroanilino)fluorane; 3-(N-ethyl-p-toluidino)-6-methyl-7-anilinofluorane; 3-(N-ethyl-N-isoamylamino)-6-methyl-7-anilinofluorane; 3-(N-ethyl-N-isoamylamino)-6-chloro-7-anilinofluorane; 3-(N-ethyl-N-tetrahydrofurfurylamino)-6-methyl-7-anilinofluorane; 3-(N-ethyl-N-isobutylamino)-6-methyl-7-anilinofluorane; 3-(N-ethyl-N-ethoxypropylamino)-6-methyl-7-anilinofluorane; 3-cyclohexylamino-6-chlorofluorane; 2-(4-oxahexyl)-3-dimethylamino-6-methyl-7-anilinofluorane; 2-(4-oxahexyl)-3-diethylamino-6-methyl-7-anilinofluorane;2-(4-oxahexyl)-3-dipropylamino-6-methyl-7-anilinofluorane; 2-methyl-6-p-(p-dimethylaminophenyl)aminoanilinofluorane; 2-methoxy-6-p-(p-dimethylaminophenyl)aminoanilinofluorane; 2-chloro-3-methyl-6-p-(p-phenylaminophenyl)aminoanilinofluorane; 2-chloro-6-p-(p-dimethylaminophenyl)aminoanilinofluorane; 2-nitro-6-p-(p-diethylaminophenyl)aminoanilinofluorane; 2-amino-6-p-(p-diethylaminophenyl)aminoanilinofluorane; 2-diethylamino-6-p-(p-diethylaminophenyl)aminoanilinofluorane; 2-phenyl-6-methyl-6-p-(p-phenylaminophenyl)aminoanilinofluorane; 2-benzyl-6-p-(p-phenylaminophenyl)aminoanilinofluorane; 2-hydroxy-6-p-(p-phenylaminophenyl)aminoanilinofluorane; 3-methyl-6-p-(p-dimethylaminophenyl)aminoanilinofluorane; 3-diethylamino-6-p-(p-diethylaminophenyl)aminoanilinofluorane; 3-diethylamino-6-p-(p-dibutylaminophenyl)aminoanilinofluorane; 2,4-dimethyl-6-[(4-dimethylamino)anilino]-fluorane;

[0035] <Fluorene-based leuco dyes> 3,6,6'-Tris(dimethylamino)spiro[fluorene-9,3'-phthalide]; 3,6,6'-Tris(diethylamino)spiro[fluorene-9,3'-phthalide]

[0036] <Divinyl leuco dyes> 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

[0037] <Other> 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindole-3-yl)-4-azaphthalide; 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-octyl-2-methylindole-3-yl)-4-azaphthalide; 3-(4-cyclohexylethylamino-2-methoxyphenyl)-3-(1-ethyl-2-methylindole-3-yl)-4-azaphthalide; 3,3-bis(1-ethyl-2-methylindole-3-yl)phthalide; 3,6-bis(diethylamino)fluoran-γ-(3'-nitro)anilinolactam; 3,6-bis(diethylamino)fluoran-γ-(4'-nitro)anilinolactam; 1,1-bis-[2',2',2'',2''-tetrakis-(p-dimethylaminophenyl)-ethenyl]-2,2-dinitrile ethane; 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]-methylmalonate dimethyl ester

[0038] Conventionally known sensitizers can be used as sensitizers for the thermal recording material of the present invention. Such sensitizers include fatty acid amides such as stearic acid amide and palmitic acid amide, ethylenebisamide, 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, and pheny Examples of sensitizers include, but are not limited to, α-naphthyl carbonate, 1,4-diethoxynaphthalene, phenyl 1-hydroxy-2-naphthoate, o-xylene-bis-(phenyl ether), 4-(m-methylphenoxymethyl)biphenyl, 4,4'-ethylenedioxy-bis-benzoate dibenzyl ester, dibenzoyloxymethane, 1,2-di(3-methylphenoxy)ethylene, bis[2-(4-methoxyphenoxy)ethyl]ether, methyl p-nitrobenzoate, and phenyl p-toluenesulfonate. These sensitizers may be used individually or in combination of two or more.

[0039] Furthermore, the following binders can be used in combination, to the extent that they do not impair the desired performance. Specifically, polyvinyl alcohols such as fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, olefin-modified polyvinyl alcohol, nitrile-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, terminal alkyl-modified polyvinyl alcohol, etc., cellulose ethers such as hydroxyethylcellulose, methylcellulose, ethylcellulose, acetylcellulose and their derivatives, polyacrylamide, cationic polyacrylamide, etc. Examples include polyacrylamides such as nionic polyacrylamide and amphoteric polyacrylamide; urethane resins such as polyester polyurethane resins, polyether polyurethane resins, and polyurethane ionomer resins; styrene-butadiene resins such as styrene-butadiene copolymers, styrene-butadiene-acrylonitrile copolymers, and styrene-butadiene-acrylic copolymers; polyolefin resins such as polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, and ethylene-vinyl acetate copolymers; polyvinyl chloride, polyvinylidene chloride, polyacrylic acid esters, rubber arabic, polyvinyl butyral, polystyrene and copolymers thereof; silicone resins, petroleum resins, terpene resins, ketone resins, and coumarone resins. These may be used individually or in combination of two or more.

[0040] The thermal recording layer of the present invention may further contain a carboxyl group-containing resin as a binder, and may also contain an epichlorohydrin-based resin and a polyamine / polyamide-based resin (excluding those contained in the epichlorohydrin-based resin) as crosslinking agents.

[0041] Examples of carboxyl group-containing resins used in the present invention include resins containing monofunctional acrylic monomers having carboxyl groups, such as methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, glycidyl methacrylate, and tetrahydrofrifuryl methacrylate; oxidized starch; carboxyl-methylcellulose; and carboxyl-modified polyvinyl alcohol obtained by introducing carboxyl groups into polyvinyl alcohol. However, it is particularly preferable to use carboxyl-modified polyvinyl alcohol, which has excellent heat resistance and plasticizer resistance. The carboxyl-modified polyvinyl alcohol used in the present invention can be obtained as a reaction product of polyvinyl alcohol with polycarboxylic acids such as fumaric acid, phthalic anhydride, mellic anhydride, and itaconic anhydride, or as an ester of these reaction products, or as a saponified copolymer of vinyl acetate with ethylenically unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid, and methacrylic acid. Specifically, examples include the production methods illustrated in Example 1 or 4 of Japanese Patent Publication No. 53-91995. Furthermore, the degree of saponification of the carboxyl-modified polyvinyl alcohol is preferably 72 to 100 mol%, and the degree of polymerization is preferably 500 to 2400, more preferably 1000 to 2000.

[0042] Specific examples of epichlorohydrin resins used in the present invention include polyamide epichlorohydrin resins and polyamine epichlorohydrin resins, which can be used alone or in combination. Furthermore, there are no particular restrictions on the amine present in the main chain of the epichlorohydrin resin, and primary to quaternary amines can be used. In addition, for good water resistance, a cationization degree of 5 meq / g·Solid or less (measured at pH 7) and a molecular weight of 500,000 or more are preferred. Examples of commercially available products include Sumirez Resin 650(30), Sumirez Resin 675A, Sumirez Resin 6615 (all manufactured by Sumitomo Chemical Co., Ltd.), WS4002, WS4020, WS4024, WS4030, WS4046, WS4010, and CP8970 (all manufactured by Seikoh PMC Co., Ltd.).

[0043] In the present invention, polyamine / polyamide resins (excluding those included in epichlorohydrin resins) mean polyamine resins and / or polyamide resins, and are compounds different from the epichlorohydrin resins mentioned above. Specifically, examples include polyamidourea resins, polyalkylene polyamine resins, polyalkylene polyamide resins, polyamine polyurea resins, modified polyamine resins, modified polyamide resins, polyalkylene polyamine urea formalin resins, and polyalkylene polyamine polyamide polyurea resins. Commercially available products include: Sumire's Resin 302 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire's Resin 712 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire's Resin 703 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire's Resin 636 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire's Resin SPI-100 (manufactured by Sumitomo Chemical: modified polyamine resin), Sumire's Resin SPI-102A (manufactured by Sumitomo Chemical: modified polyamine resin), and Sumire's Resin SPI-106N (manufactured by Sumitomo Chemical: modified polyamide resin). Examples include, but are not particularly limited, and can be used individually or in combination of two or more. From the viewpoint of color development sensitivity, it is preferable to use polyamine resins (polyalkylene polyamine resin, polyamine polyurea resin, modified polyamine resin, polyalkylene polyamine urea formalin resin, polyalkylene polyamine polyamide polyurea resin).

[0044] In addition to the above-mentioned components, pigments, lubricants, crosslinking agents, and the like can be used in the thermal recording layer of the present invention. Examples of pigments used in this invention include inorganic or organic fillers such as silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium dioxide, and aluminum hydroxide. These may be used individually or in combination of two or more. Examples of lubricants used in the present invention include fatty acid metal salts such as zinc stearate and calcium stearate, waxes, silicone resins, and the like. Furthermore, in the present invention, polyimine resins, glyoxal, methylolmelamine, melamineformaldehyde resin, melamineurea resin, potassium persulfate, ammonium persulfate, sodium persulfate, ferric chloride, magnesium chloride, borax, boric acid, alum, ammonium chloride, etc. may be used in combination as crosslinking agents, to the extent that they do not hinder the desired effects on the above-mentioned problems. In addition, benzophenone-based or triazole-based UV absorbers, dispersants, defoamers, fluorescent dyes, etc., may be used.

[0045] The types and amounts of metal chelate-type colorants, electron-donating leuco dyes, electron-accepting organic colorants, and other components used in the thermal recording material of the present invention are determined according to the required performance and recording suitability, and are not particularly limited, but typically, about 0.1 to 10 parts by weight of a polyvalent hydroxyaromatic compound, which is the electron donor, is used per 1 part by weight of iron stearate, which is the electron acceptor of the metal chelate-type colorant. When a pigment is used, typically, about 0.5 to 50 parts by weight of the pigment is used per 1 part by weight of a higher fatty acid metal salt, which is the electron acceptor of the metal chelate-type colorant. The electron-donating leuco dye is used in an amount of 0.1 to 10 parts by weight per 1 part by weight of a higher fatty acid metal salt, and an electron-accepting organic developer and a sensitizer are used in an amount of 0.5 to 10 parts by weight, preferably about 0.5 to 10 parts by weight, per 1 part by weight of the electron-donating leuco dye. In the thermal recording layer of the present invention, the ratio of the total content (solid content) of metal chelate-type color-developing components to the total content (solid content) of electron-donating leuco dyes and electron-accepting color developers is usually 0.04 to 0.18, preferably 0.05 to 0.15. Furthermore, when the thermal recording layer of the present invention contains first and second urea compounds as color developers, the content of the second urea compound in the thermal recording layer is preferably 0.1 to 30.0 parts by weight, more preferably 0.5 to 25.0 parts by weight, even more preferably 1.0 to 20.0 parts by weight, and particularly preferably 2.0 to 15.0 parts by weight, per 1.0 part by weight of the first urea compound. Also, when the thermal recording layer of the present invention contains first and third urea compounds, the content of the third urea compound in the thermal recording layer is preferably 0.1 to 30.0 parts by weight, more preferably 0.5 to 25.0 parts by weight, even more preferably 1.0 to 20.0 parts by weight, and particularly preferably 2.0 to 15.0 parts by weight, per 1.0 part by weight of the first urea compound. Furthermore, when the thermal recording layer of the present invention contains the second and third urea compounds, the content of the third urea compound in the thermal recording layer is preferably 0.1 to 30.0 parts by weight, more preferably 0.3 to 25.0 parts by weight, even more preferably 0.5 to 20.0 parts by weight, and particularly preferably 0.7 to 15.0 parts by weight, per 1.0 part by weight of the second urea compound.

[0046] The types and amounts of other optional components, such as binders, pigments, lubricants, crosslinking agents, image stabilizers, and other components, are determined according to the required performance and recording suitability and are not particularly limited. However, typically, the binder should be about 5 to 50 parts by weight in solids per 100 parts by weight of the thermal recording layer (solids), and the pigment should be about 0 to 50 parts by weight in solids per 100 parts by weight of the thermal recording layer (solids). When using lubricants, the lubricant content should be about 5 to 10 parts by weight in solids per 100 parts by weight of the thermal recording layer (solids). In the case where the thermal recording layer of the present invention further contains a carboxyl group-containing resin as a binder and an epichlorohydrin-based resin and a polyamine / polyamide-based resin (excluding those contained in the epichlorohydrin-based resin) as crosslinking agents, the amount of carboxyl group-containing resin is preferably 0.1 to 50 parts by weight, and more preferably 0.5 to 30 parts by weight, per 1 part by weight of the higher fatty acid metal salt which is the electron acceptor of the metal chelate-type coloring component in the thermal recording layer. Furthermore, the amounts of the epichlorohydrin-based resin and the polyamine / polyamide-based resin (excluding those contained in the epichlorohydrin-based resin) are preferably 1 to 100 parts by weight, and more preferably 5 to 50 parts by weight, per 100 parts by weight of the carboxyl group-containing resin.

[0047] The thermal recording material of the present invention may further have a protective layer on the thermal recording layer. This protective layer mainly consists of a binder and a pigment, and a crosslinking agent may be added thereto. The binder, pigment, and crosslinking agent can be any suitable material suitable for use in the thermal recording layer described above.

[0048] In this invention, an undercoat layer may be provided between the support and the thermal recording layer. This undercoat layer mainly consists of a binder and a pigment. As the binder used for the undercoat layer, the various binders used for the thermal recording layer described above can be used. One or more of these binders may be used. As pigments used for the undercoat layer, the various pigments used for the thermal recording layer described above can be used. One or more of these pigments may be used. The amount of pigment in the undercoat layer is usually 50 to 95 parts by weight, preferably 70 to 90 parts by weight, per 100 parts by weight of the total solid content of the undercoat layer. The undercoat layer may contain various auxiliary agents as needed, such as dispersants, plasticizers, pH adjusters, defoamers, water-retaining agents, preservatives, coloring dyes, and UV-blocking agents.

[0049] The thermal recording material of the present invention may have a back coat layer provided on the side of the support opposite to the thermal recording layer. This backcoat layer may contain a water-dispersible resin and a pigment. The water-dispersible resin is preferably at least one selected from the group consisting of natural rubber, diene rubber, non-diene rubber, and thermoplastic elastomer. As for the pigment, any of the pigments listed above as usable for the thermal recording layer can be used as appropriate, but aluminum hydroxide, silica, kaolin, and calcined kaolin are preferred, and aluminum hydroxide is more preferred. This backcoat layer may, as necessary, further contain lubricants, crosslinking agents, ultraviolet absorbers, dispersants, defoamers, fluorescent dyes, etc., as listed above as usable in the thermal recording layer, to the extent that it does not hinder the desired effect on the above-mentioned problem.

[0050] A thermal recording material can be obtained by applying a coating liquid, consisting of the composition formulated for each of the above-mentioned coating layers, to any support material such as paper, recycled paper, synthetic paper, film, plastic film, foamed plastic film, or nonwoven fabric. Alternatively, a composite sheet combining these materials may be used as the support material. Electron-donating leuco dyes, electron-accepting color developers, electron acceptors, electron donors, and any additional materials as needed are pulverized to a particle size of a few microns or less using a pulverizer such as a ball mill, attritor, or sand grinder, or a suitable emulsifier, and various additive materials are added according to the purpose to form a coating solution. The means of applying each of the above coating layers are not particularly limited and can be applied according to well-known and conventional techniques. For example, off-machine or on-machine coating machines equipped with various coaters such as air knife coaters, rod blade coaters, vent blade coaters, bevel blade coaters, roll coaters, curtain coaters, and spray coaters can be appropriately selected and used. The amount of thermal recording layer applied is determined according to the required performance and recording suitability and is not particularly limited, but a typical application amount is 2 to 12 g / m² in solid content. 2 It is to that extent. Furthermore, various known techniques in the field of thermal recording materials may be appropriately added, such as applying a smoothing treatment like supercalendering after coating each coating layer. [Examples]

[0051] The present invention will be illustrated below with examples, but this is not intended to limit the present invention. In each example and comparative example, unless otherwise specified, "parts" refers to "parts by weight" and "%" refers to "weight percent". Each dispersion and coating solution was prepared as follows.

[0052] A primer coating liquid was prepared by stirring and dispersing a mixture consisting of the following components. <Coating liquid for the undercoat layer> Calcined kaolin (BASF, product name: Ansilex 90) 100.0 parts Fully saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd.) Product name: PVA117, solid content 12 %) 40.0 copies Water 20.0 parts

[0053] The following dispersions of higher fatty acid metal salts (Solutions A1 and A2), polyhydric hydroxyaromatic compounds (Solution B), color developer dispersions (Solutions C1 to C6), leuco dye dispersions (Solution D), sensitizer dispersions (Solution E), and hindered phenolic compound dispersions (Solution F) were each wet-ground using a sand grinder until an average particle size of 0.5 microns was achieved.

[0054] Ferric stearate dispersion (Solution A1) Ferric stearate 6.0 parts 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water Iron-zinc behenate double salt dispersion (Solution A2) Iron-zinc behenate double salt (metal molar ratio in higher fatty acid metal double salts: iron:zinc = 2:1) (Manufactured by ADEKA Corporation, Product name: DM-1022) 6.0 units 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water

[0055] Dispersion of polyhydric hydroxyaromatic compounds (Solution B) Stearyl gallate compounds represented by the following formula (Chemical Formula 16) (manufactured by Dainippon Sumitomo Pharma Co., Ltd.) Product name: TH-S) 6.0 copies 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water [ka]

[0056] Chromogenizer dispersion (Solution C1) N-[2-(3-phenylureido)phenyl]benzenesulfonamide (Manufactured by Nippon Soda Co., Ltd., Product name: NKK1304) 6.0 parts 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water Chromogenizer dispersion (C2 solution) The urea compound represented by the following chemical formula (Chemical Formula 9) (hereinafter referred to as "urea compound A") 6.0 copies [ka] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water Chromogenizer dispersion (C3 solution) N,N'-di-[3-(p-toluenesulfonyloxy)phenyl]urea (Hereinafter referred to as "Urea Compound B.") Part 6.0 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water

[0057] Chromolytic agent dispersion (C4 solution) 4-Hydroxy-4'-Isopropoxydiphenylsulfone (manufactured by Mitsubishi Chemical Corporation) Product name: NYDS) 6.0 copies 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water Chromogen dispersant (C5 solution) Diphenyl sulfone crosslinked compound (manufactured by Nippon Soda Co., Ltd., product name: D-90) 6.0 copies 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water Chromogenizer dispersion (C6 solution) Urea urethane compound represented by formula (Chemical Formula 17) (manufactured by Fine Ace Co., Ltd.) Product name: UU) 6.0 copies [ka] 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water

[0058] Leuco dye dispersion (Solution D) 3-Dibutylamino-6-methyl-7-anilinofluorane (Manufactured by Yamamoto Kasei Co., Ltd., Product name: ODB-2) 6.0 units 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water

[0059] Sensitizer dispersion (Solution E) 1,2-Bis-(3-methylphenoxy)ethane (manufactured by Sanko Co., Ltd.) Product name: KS232) 6.0 copies 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water

[0060] Hindered phenol compound dispersion (Solution F) 1,1,3-Tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane (Manufactured by ADEKA Corporation, Product name: ADEKA Arcles DH-37) 6.0 units 5.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117) 1.5 parts water

[0061] Next, the dispersions were mixed in the following proportions to prepare coating solutions 1 to 5 for the thermal recording layer. <Thermal recording layer coating liquid 1> Ferric stearate dispersion (Solution A1) 1.2 parts Dispersion of polyhydric hydroxyaromatic compounds (Solution B) 0.8 parts 13.0 parts of developer dispersion (Solution C1) Leuco dye dispersion (Solution D) 7.0 parts Sensitizer dispersion (Solution E) 4.0 parts Hindered phenol compound dispersion (Solution F) 0.6 parts Silica dispersion (manufactured by Mizusawa Chemical Industry Co., Ltd., product name: Mizukasil P-537) 25% solids content 40.0 parts 60.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0062] <Thermal recording layer coating liquid 2> Ferric stearate dispersion (Solution A1) 1.2 parts Dispersion of polyhydric hydroxyaromatic compounds (Solution B) 0.8 parts 9.0 parts of developer dispersion (Solution C1) 4.0 parts of developer dispersion (C6 solution) Leuco dye dispersion (Solution D) 7.0 parts Sensitizer dispersion (Solution E) 4.0 parts Hindered phenol compound dispersion (Solution F) 0.6 parts Silica dispersion (Mizukasil P-537) 40.0 parts 60.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0063] <Thermal recording layer coating liquid 3> 13.0 parts of developer dispersion (Solution C1) 13.0 parts of developer dispersion (C6 solution) Leuco dye dispersion (Solution D) 7.0 parts Sensitizer dispersion (Solution E) 4.0 parts Hindered phenol compound dispersion (Solution F) 0.6 parts Silica dispersion (Mizukasil P-537) 40.0 parts 60.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0064] <Thermal recording layer coating liquid 4> Iron-zinc behenate double salt dispersion (Solution A2) 1.5 parts Dispersion of polyhydric hydroxyaromatic compounds (Solution B) 1.0 part 13.0 parts of developer dispersion (Solution C1) Leuco dye dispersion (Solution D) 7.0 parts Sensitizer dispersion (Solution E) 4.0 parts Hindered phenol compound dispersion (Solution F) 0.6 parts Silica dispersion (Mizukasil P-537) 40.0 parts 60.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0065] <Thermal recording layer coating liquid 5> 13.0 parts of developer dispersion (C4 solution) 13.0 parts of developer dispersion (C5 solution) Leuco dye dispersion (Solution D) 7.0 parts Sensitizer dispersion (Solution E) 4.0 parts Hindered phenol compound dispersion (Solution F) 0.6 parts Silica dispersion (Mizukasil P-537) 40.0 parts 60.0 parts of fully saponified polyvinyl alcohol aqueous solution (PVA117)

[0066] [Example 1] Support (47g / m 2 On one side of the high-quality paper, apply the primer coating liquid, with a solid content of 10.0 g / m². 2 After coating using the bent blade method, the paper was dried to obtain a base coat layer. Next, the thermal recording layer coating liquid 1 is applied to the undercoat layer of this undercoat layer coated paper at a solid content rate of 5.0 g / m². 2 After coating using the rod blade method, the surface was dried, and then treated with a supercalender to achieve a smoothness of 500 to 1000 seconds on the surface coated with the thermal recording layer, thereby producing a thermal recording material.

[0067] [Example 2] A thermal recording body was prepared in the same manner as in Example 1, except that the developer dispersion C1 was replaced with C2 in the thermal recording layer coating solution 1. [Example 3] A thermal recording body was prepared in the same manner as in Example 1, except that the developer dispersion C1 was replaced with C3 in the thermal recording layer coating solution 1. [Example 4] A thermal recording body was prepared in the same manner as in Example 1, except that the thermal recording layer coating liquid 1 was changed to thermal recording layer coating liquid 2.

[0068] [Comparative Example 1] A thermal recording body was prepared in the same manner as in Example 1, except that the developer dispersion C1 was replaced with C4 in the thermal recording layer coating solution 1. [Comparative Example 2] A thermal recording body was prepared in the same manner as in Example 1, except that the thermal recording layer coating liquid 1 was changed to thermal recording layer coating liquid 3. [Comparative Example 3] A thermal recording body was prepared in the same manner as in Comparative Example 2, except that the developer dispersion C1 was replaced with C2 in the thermal recording layer coating solution 3. [Comparative Example 4] A thermal recording body was prepared in the same manner as in Comparative Example 2, except that the developer dispersion C1 was replaced with C3 in the thermal recording layer coating solution 3. [Comparative Example 5] A thermal recording body was prepared in the same manner as in Example 1, except that the thermal recording layer coating liquid 1 was changed to thermal recording layer coating liquid 5. [Comparative Example 6] A thermal recording body was prepared in the same manner as in Example 1, except that the thermal recording layer coating liquid 1 was changed to thermal recording layer coating liquid 4.

[0069] The following evaluations were performed on the fabricated thermal recording material. <Color reproduction performance (print density)> The fabricated thermal recording material was printed with a checkerboard pattern at a printing speed of 50 mm / sec using an Okura Electric TH-PMD (thermal recording paper printing tester, equipped with a Kyocera thermal head) and applied energies of 0.21 mJ / dot, 0.31 mJ / dot, and 0.41 mJ / dot. The print density of the printed area was measured using a Macbeth densitometer (RD-914, using an amber filter) to evaluate the color development performance (print density).

[0070] <Solvent immersion resistance> The fabricated thermal recording material was printed with a checkerboard pattern using an Okura Electric TH-PMD (thermal recording paper printing tester, equipped with a Kyocera thermal head) at an applied energy of 0.41 mJ / dot and a printing speed of 50 mm / sec. The printed thermal recording material was immersed in a 50% ethanol solution for one week, and then left to stand for 3 hours under environmental conditions of 23°C × 50% RH. The solvent resistance of the printed area was visually evaluated according to the following criteria. Remaining percentage (%) = (Print density of the printed area after processing / Print density of the printed area before processing) × 100 Excellent: Easily readable Acceptable: The printing is faint, but still legible. Not possible: The entire printed area is not visible to the naked eye. <Solvent resistance> Ethanol (50.0%) was applied to the blank area of ​​the prepared thermal recording material using a cotton swab, and after being left to stand for 24 hours under environmental conditions of 23°C × 50%RH, it was visually evaluated according to the following criteria. Excellent: No color at all Possible: Shows slight coloration. Not suitable: Strongly colored

[0071] <Heat resistance of the blank area> The fabricated thermal recording material was treated under environmental conditions of 70°C for 24 hours, and then left to stand for 3 hours under environmental conditions of 23°C × 50%RH. The density of the non-printed area (white paper area) was measured using a Macbeth densitometer (RD-914, using an amber filter), and the background color development value was calculated from the difference in values ​​before and after processing. The heat resistance of the non-printed area (white paper area) was evaluated according to the following criteria. Background color value = (Density of unprinted area after processing) - (Density of unprinted area before processing) Excellent: Base color development value is less than 0.2 Acceptable: Base color development value is 0.2 or higher and less than 0.5 Not acceptable: Base color value is 0.5 or higher <Resistance to yellowing of the blank area> The fabricated thermal recording material was left to stand for one week under environmental conditions of 40°C and 75% Rh, and then left to stand for 3 hours under environmental conditions of 23°C and 50% RH. The b-value of the non-printed area (white paper area) was measured using a CMS-35SPXM manufactured by Murakami Color Technology Laboratory Co., Ltd., and the heat resistance of the non-printed area (white paper area) was evaluated according to the following criteria. Excellent: b value less than 2.0 Acceptable: b value is 2.0 or greater and less than 4.0 Not acceptable: b value is 4.0 or higher

[0072] The evaluation results are shown in Table 1. [Table 1]

Claims

1. A thermal recording body having a thermal recording layer on a support containing a colorless or pale-colored electron-donating leuco dye and an electron-accepting color developer, The thermal recording layer contains, as a metal chelate-type coloring component, iron stearate and the following general formula (Chemical Formula 1) 【Chemistry 1】 (In the formula, R is an alkyl group having 18 to 35 carbon atoms) 【Chemistry 2】 (In the formula, R ａ represents an alkyl group with 18 to 35 carbon atoms. ) represents -X- represents -CH ２ -, -CO ２ -, -CO-, -O-, -CONH-, -CONR ｂ - (wherein, R ｂ ) represents an alkyl group with 18 to 35 carbon atoms. ), -SO ２ -, -SO ３ - or - SO ２ It contains a polyvalent hydroxyaromatic compound represented as NH-, where p is an integer of 2 or 3, The electron-accepting color developer contains at least one urea compound represented by the following general formula (Chemical Formula 3), A thermal recording medium in which the total content (solid content) of the urea compound relative to all of the electron-accepting color developer is 80% by weight or more. 【Transformation 3】 (In the formula, Y represents -O- or -NH-, and R １ represents a hydrogen atom or -SO ２ -R ３ where R ３ represents a substituted or unsubstituted alkyl group, aralkyl group or aryl group, and R ２ represents a hydrogen atom or an alkyl group, m represents an integer of 0 to 2, and n represents 0 or 1.)

2. The thermal recording body according to claim 1, wherein the urea compound is selected from the group consisting of (1) to (3) below. (1) A first urea compound represented by the following general formula (Chemical Formula 4), 【Chemistry 4】 (In the formula, R １ , R ２ , R ３ (And n are defined in the same way as above.) (2) A second urea compound represented by the following general formula (Chemical Formula 5), 【Transformation 5】 (In the formula, R ２ It is defined in the same way as above, R ４ ~R ８ Each of these may be the same or different, and represents a hydrogen atom, halogen atom, nitro group, amino group, alkyl group, alkoxy group, aryloxy group, alkylcarbonyloxy group, arylcarbonyloxy group, alkylcarbonylamino group, arylcarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, monoalkylamino group, dialkylamino group, or arylamino group, and m is defined in the same manner as above. (3) A third urea compound represented by the following formula (Chemical Formula 6) 【Transformation 6】 (In the formula, R ２ , R ４ ~R ８ (This is defined in the same way as above.)

3. The thermal recording body according to claim 2, wherein the thermal recording layer contains at least two urea compounds selected from the group consisting of (1) to (3) above as an electron-accepting color developer, provided that two or more are not selected from each of (1), (2) or (3).

4. The thermal recording body according to claim 2 or 3, wherein the first urea compound is represented by the following general formula (Chemical Formula 7). 【Transformation 7】 (In the formula, R ２ It is defined in the same way as above, R ３ These may be the same or different, and are groups represented by the following formula (Chemical Formula 14), and are R in the benzene ring of the general formula (Chemical Formula 7). ３ -SO ３ The position of -O- may be the same or different, and it is the 3rd, 4th, or 5th position. 【Chemistry 14】 (In the formula, R ４ ~R ８ These may be the same or different, and each represents a hydrogen atom, halogen atom, nitro group, amino group, alkyl group, alkoxy group, aryloxy group, alkylcarbonyloxy group, arylcarbonyloxy group, alkylcarbonylamino group, arylcarbonylamino group, alkylsulfonylamino group, arylsulfonylamino group, monoalkylamino group, dialkylamino group, or arylamino group.

5. The thermal recording body according to claim 4, wherein the first urea compound is represented by the following general formula (Chemical Formula 8). 【Transformation 8】 (In the formula, R ９ (Each element may be the same or different, and represents an alkyl group or an alkoxy group, where 'o' represents an integer from 0 to 3.)

6. In the first urea compound, R ９ represents an alkyl group with 1 to 4 carbon atoms, o represents an integer from 0 to 1, and R in the benzene ring. ９ The thermal recording body according to claim 5, wherein the position is the 4th position.

7. The thermal recording body according to any one of claims 2 to 6, wherein the second urea compound is represented by the following general formula (Chemical Formula 9) or the following general formula (Chemical Formula 10). 【Chemistry 9】 【Chemistry 10】

8. The thermal recording body according to any one of claims 2 to 7, wherein the third urea compound is N-[2-(3-phenylureido)phenyl]benzenesulfonamide.

9. The thermal recording body according to any one of claims 1 to 8, wherein the content (solid content) of the urea compound in the thermal recording layer is 1.0 to 70.0% by weight.

10. The thermal recording body according to any one of claims 2 to 9, wherein the thermal recording layer contains a color developer other than the first urea compound, the second urea compound, and the third urea compound, and the total content (solid content) of the first urea compound, the second urea compound, and the third urea compound relative to the total color developer contained in the thermal recording layer is 90% by weight or more.

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