Thermosensitive recording layer, thermosensitive recording medium, thermosensitive recording layer forming liquid, production method of thermosensitive recording medium, and image recording method

Abstract

To provide a thermosensitive recording medium that can form an image of high concentration and has all of hot water resistance, water resistance, ethanol resistance, temperature and humidity resistance, wet abrasion resistance, and heat resistance.SOLUTION: A thermosensitive recording medium includes a support and a thermosensitive recording layer disposed on the support. The thermosensitive recording layer includes a compound represented by the general formula (1) in the figure and a styrene-acrylic resin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a heat-sensitive recording layer forming liquid, a heat-sensitive recording medium, a method for manufacturing the same, and an image recording method.

Background Art

[0002] Compared with other recording methods, the heat-sensitive recording method using a heat-sensitive recording medium does not require processes such as development and fixing, can record in a short time using a relatively simple device, and has the advantage of low cost. Therefore, it has been rapidly used in the food field that emphasizes the reliability of images such as bento and prepared foods.

[0003] In the food field, heat-sensitive recording media have come to be used for labels of PET bottles, labels of fresh foods, etc., and usage situations where they are exposed to water and warm water are assumed. When the image part of the heat-sensitive recording medium comes into contact with water and warm water, the contacted image part may fade. In particular, there is a risk of fading at the temperature of hot drinks in vending machines (for example, 60 ° C for several hours), the temperature of hot water coming out of faucets (for example, 60 ° C for several minutes), the temperature of the warm water course of washing machines (40 ° C to 60 ° C for several hours), etc. In addition, for packaging films of various containers such as PET bottles for soft drinks, metal cans for canned coffee, bottles (jars) for drink agents, pharmaceuticals, beer, etc., and packaging labels in the POS field for fresh foods, bento, prepared foods, etc., in addition to the above-mentioned heat and water resistance, it is required to have all of ethanol resistance, temperature and humidity resistance, water rub resistance, and heat resistance.

[0004] Therefore, for example, in order to improve the water resistance of the image part, polyvinyl alcohol and polyamide epichlorohydrin resin are contained in the heat-sensitive recording layer, or a hydrophobic resin emulsion such as vinyl acetate emulsion, acrylic emulsion, SBR latex is used as a binder for the heat-sensitive recording layer, or a non-phenolic developer that does not contain a phenolic compound is used as a developer for the heat-sensitive recording layer (see, for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a heat-sensitive recording medium that has all of heat-resistant water resistance, water resistance, ethanol resistance, heat and humidity resistance, water rubbing resistance, and heat resistance, and can obtain a high-concentration image.

Means for Solving the Problems

[0006] The heat-sensitive recording medium of the present invention as means for solving the above problems is a heat-sensitive recording medium having a support and a heat-sensitive recording layer on the support, wherein the heat-sensitive recording layer contains a compound represented by the following general formula (1) and a styrene-acrylic resin.

Chemical formula

Effects of the Invention

[0007] According to the present invention, it is possible to provide a heat-sensitive recording medium that has all of heat-resistant water resistance, water resistance, ethanol resistance, heat and humidity resistance, water rubbing resistance, and heat resistance, and can obtain a high-concentration image.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0009] (Thermal Recording Medium) The thermal recording medium of the present invention is a thermal recording medium having a support and a thermal recording layer on the support, wherein the thermal recording layer contains a compound represented by the following general formula (1) and a styrene-acrylic resin, and further has other layers as required.

[0010]

Chemical formula

[0011] In the prior art, by using a specific non-phenolic color former, water resistance can be maintained against water at normal temperature (25 °C), but there is a problem that the image portion fades when exposed to warm water (60 °C or higher).

[0012] In the present invention, there is provided a thermal recording medium having a support and a thermal recording layer on the support, wherein the thermal recording layer contains a compound represented by the general formula (1) and a styrene-acrylic resin, thereby having all of hot water resistance, water resistance, ethanol resistance, temperature and humidity resistance, water rubbing resistance and heat resistance, and a high-concentration image can be obtained.

[0013] <Thermal recording layer> The thermal recording layer preferably contains a compound represented by the general formula (1) and a styrene-acrylic resin, contains a leuco dye and a photothermal conversion material, and further contains other components as necessary.

[0014] <<Compound represented by general formula (1)>> The compound represented by the general formula (1) is a non-phenolic color former, and non-phenolic means not having a phenol skeleton. By containing a non-phenolic color former, it is not necessary to contain a phenolic color former that may correspond to endocrine disruptors, and thus it is excellent in terms of environmental impact.

[0015] In the above general formula (1) and the above general formula (2), R2 is a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms, an unsubstituted or 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 an aralkyl group having 7 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms substituted with a halogen atom, and a plurality of R2 may be the same or different. A1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A plurality of A1 may be the same or different.

[0016] In the above general formula (3), R represents an alkyl group, and n represents an integer from 0 to 3. The number of carbon atoms in the alkyl group of R may be 1 to 12, may be 1 to 8, or may be 1 to 4.

[0017] In the above general formula (1), the substitution positions of a plurality of R2-SO3- may be the same substitution position or different substitution positions. Preferably, the 3-position, 4-position or 5-position is preferred, and more preferably the 3-position.

[0018] Examples of the linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms of R2 include linear, branched or alicyclic alkyl groups having 1 to 12 carbon atoms such as 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, lauryl group and the like.

[0019] Examples of the aralkyl group include unsubstituted or alkyl group-, alkoxy group-, aralkyl group-, aryl group- or halogen atom-substituted aralkyl 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, p-i-propylbenzyl group, p-t-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, p-chlorobenzyl group and the like.

[0020] Examples of the aryl group include unsubstituted or alkyl group-, alkoxy group-, aralkyl group-, aryl group- or halogen atom-substituted aryl 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, p-i-propylphenyl group, p-t-butylphenyl group, p-methoxyphenyl group, 3,4-dimethoxyphenyl group, p-ethoxyphenyl group, p-chlorophenyl group, 1-naphthyl group, 2-naphthyl group, t-butylated naphthyl group and the like.

[0021] The substitution positions of the plurality of A1 may be the same or different. Preferably, the 3-position, 4-position and 5-position are preferred. A1 is an alkyl group such as a hydrogen atom, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group and the like.

[0022] Specific examples of the compounds represented by the above general formulas (1) to (3) include the following compounds, but are not limited to these compounds, and two or more compounds may be used in combination as the color former.

[0023] Furthermore, by using in combination with existing color formers, for example, known non-phenolic color formers such as N-3-[(p-toluenesulfonyl)oxy]phenyl-N'-(p-toluenesulfonyl)-urea and N-[2-(3-phenylureido)phenyl]-benzenesulfonamide, and known color formers such as 4,4'-isopropylidenediphenol (BPA), 4,4'-dihydroxydiphenylsulfone (BPS), 4-allyloxy-4'-hydroxydiphenylsulfone, 4-allyloxy-4'-hydroxy-diphenylsulfone, 4-hydroxy-4'-isopropoxysulfone, N-(m-tolylaminocarbonyl)-methionine, N-(m-tolylaminocarbonyl)-phenylalanine, and N-(phenylaminocarbonyl)-phenylalanine, it becomes possible to further improve the storage stability, which is a problem of these known color formers.

[0024] Examples of the compounds represented by the above general formulas (1) to (3) include N,N'-di-[3-(benzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-5-methyl-phenyl]urea, N,N'-di-[3-(benzenesulfonyloxy)-4-propyl-phenyl]urea,

[0025] 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-methyl-phenyl]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-(p-t-butylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[3-(m-methoxybenzenesulfonyloxy)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,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,

[0026] N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(m-toluenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(o-toluenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(p-xylenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(mesitylenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(1-naphthalenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(2-naphthalenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(benzylsulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(ethanesulfonyloxy)phenyl]urea, N-[3-(Benzenesulfonyloxy)phenyl]-N'-[3-(benzenesulfonyloxy)-4-methylphenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(m-toluenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(o-toluenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)-4-methylphenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea,N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(2-naphthalenesulfonyloxy)phenyl]urea,

[0027] N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(benzylsulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(p-methylbenzylsulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzylsulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(methanesulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(propanesulfonyloxy)phenyl]urea, N-[3-(p-Toluenesulfonyloxy)phenyl]-N'-[3-(butanesulfonyloxy)phenyl]urea,

[0028] N,N'-Di-[3-(benzylsulfonyloxy)phenyl]urea, N,N'-Di-[3-(benzylsulfonyloxy)-4-methyl-phenyl]urea, N,N'-Di-[3-(phenylethanesulfonyloxy)phenyl]urea, N,N'-Di-[3-(phenylpropanesulfonyloxy)phenyl]urea, N,N'-Di-[3-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0029] N-[3-(benzylsulfonyloxy)phenyl]-N'-[3-(p-methoxybenzylsulfonyloxy)phenyl]urea, N-[3-(benzylsulfonyloxy)phenyl]-N'-[3-(ethanesulfonyloxy)phenyl]urea, N-[3-(benzylsulfonyloxy)phenyl]-N'-[3-(butanesulfonyloxy)phenyl]urea,

[0030] N,N'-Di-[3-(methanesulfonyloxy)phenyl]urea, N,N'-di-[3-(methanesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[3-(methanesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-di-[3-(methanesulfonyloxy)-5-methyl-phenyl]urea, N,N'-di-[3-(methanesulfonyloxy)-4,5-dimethyl-phenyl]urea, N,N'-di-[3-(ethanesulfonyloxy)phenyl]urea, N,N'-di-[3-(ethanesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[3-(1-propanesulfonyloxy)phenyl]urea, N,N'-di-[3-(2-propanesulfonyloxy)phenyl]urea, N,N'-di-[3-(butanesulfonyloxy)phenyl]urea, N,N'-di-[3-(pentanesulfonyloxy)phenyl]urea, N,N'-di-[3-(hexanesulfonyloxy)phenyl]urea, N,N'-di-[3-(cyclohexanesulfonyloxy)phenyl]urea, N,N'-di-[3-(dodecanesulfonyloxy)phenyl]urea,

[0031] N-[3-(methanesulfonyloxy)phenyl]-N'-[3-(ethanesulfonyloxy)phenyl]urea, N-[3-(ethanesulfonyloxy)phenyl]-N'-[3-(propanesulfonyloxy)phenyl]urea, N-[3-(methanesulfonyloxy)phenyl]-N'-[3-(butanesulfonyloxy)phenyl]urea, N-[3-(ethanesulfonyloxy)phenyl]-N'-[3-(cyclohexanesulfonyloxy)phenyl]urea,

[0032] N,N'-Di-[4-(benzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(benzenesulfonyloxy)-3-methyl-phenyl]urea, N,N'-di-[4-(benzenesulfonyloxy)-3-ethyl-phenyl]urea, N,N'-di-[4-(benzenesulfonyloxy)-3-propyl-phenyl]urea, N,N'-di-[4-(benzenesulfonyloxy)-3-t-butyl-phenyl]urea,

[0033] N,N'-Di-[4-(o-toluenesulfonyloxy)phenyl]urea, N,N'-di-[4-(m-toluenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-toluenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-toluenesulfonyloxy)-3-methyl-phenyl]urea,

[0034] N,N'-Di-[4-(p-xylenesulfonyloxy)phenyl]urea, N,N'-di-[4-(m-xylenesulfonyloxy)phenyl]urea, N,N'-di-[4-(mesitylenesulfonyloxy)phenyl]urea,

[0035] N,N'-Di-[4-(1-naphthalenesulfonyloxy)phenyl]urea, N,N'-di-[4-(2-naphthalenesulfonyloxy)phenyl]urea,

[0036] N,N'-Di-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-propylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-isopropylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-t-butylbenzenesulfonyloxy)phenyl]urea,

[0037] N,N'-Di-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(m-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(o-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(m,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-propoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-butoxybenzenesulfonyloxy)phenyl]urea,

[0038] N,N'-Di-[4-(p-cumylbenzylsulfonyloxy)phenyl]urea, N,N'-di-[4-(p-cumylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(o-phenylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[4-(p-phenylbenzenesulfonyloxy)phenyl]urea,

[0039] N,N'-Di-[4-(p-chlorobenzenesulfonyloxy)phenyl]urea,

[0040] N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(p-toluenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(m-toluenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(o-toluenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(p-xylenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(mesitylenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(1-naphthalenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(2-naphthalenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea, N-[4-(Benzenesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(m-toluenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(o-toluenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(2-naphthalenesulfonyloxy)phenyl]urea,

[0041] N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(p-methylbenzylsulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(p-methoxybenzylsulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(methanesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(propanesulfonyloxy)phenyl]urea, N-[4-(p-Toluenesulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea,

[0042] N,N'-Di-[4-(benzylsulfonyloxy)phenyl]urea, N,N'-Di-[4-(benzylsulfonyloxy)-3-methyl-phenyl]urea, N,N'-Di-[4-(phenylethanesulfonyloxy)phenyl]urea, N,N'-Di-[4-(phenylpropanesulfonyloxy)phenyl]urea, N,N'-Di-[4-(p-methoxybenzylsulfonyloxy)phenyl)urea,

[0043] N-[4-(benzylsulfonyloxy)phenyl]-N'-[4-(methanesulfonyloxy)phenyl]urea, N-[4-(benzylsulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea,

[0044] N,N'-Di-[4-(methanesulfonyloxy)phenyl]urea, N,N'-di-[4-(methanesulfonyloxy)-3-methyl-phenyl]urea, N,N'-di-[4-(methanesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-di-[4-(methanesulfonyloxy)-3-methyl-phenyl]urea, N,N'-di-[4-(methanesulfonyloxy)-3,5-dimethyl-phenyl]urea, N,N'-di-[4-(ethanesulfonyloxy)phenyl]urea, N,N'-di-[4-(ethanesulfonyloxy)-3-methyl-phenyl]urea, N,N'-di-[4-(1-propanesulfonyloxy)phenyl]urea, N,N'-di-[4-(2-propanesulfonyloxy)phenyl]urea, N,N'-di-[4-(butanesulfonyloxy)phenyl]urea, N,N'-di-[4-(pentanesulfonyloxy)phenyl]urea, N,N'-di-[4-(hexanesulfonyloxy)phenyl]urea, N,N'-di-[4-(cyclohexanesulfonyloxy)phenyl]urea, N,N'-di-[4-(dodecanesulfonyloxy)phenyl]urea,

[0045] N-[4-(methanesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[4-(methanesulfonyloxy)phenyl]-N'-[4-(propanesulfonyloxy)phenyl]urea,

[0046] N,N'-Di-[2-(benzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(benzenesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[2-(benzenesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-di-[2-(benzenesulfonyloxy)-5-methyl-phenyl]urea, N,N'-di-[2-(benzenesulfonyloxy)-4-propyl-phenyl]urea,

[0047] N,N'-Di-[2-(o-toluenesulfonyloxy)phenyl]urea, N,N'-di-[2-(m-toluenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-toluenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-toluenesulfonyloxy)-4-methyl-phenyl]urea,

[0048] N,N'-Di-[2-(p-xylenesulfonyloxy)phenyl]urea, N,N'-di-[2-(m-xylenesulfonyloxy)phenyl]urea, N,N'-di-[2-(mesitylenesulfonyloxy)phenyl]urea,

[0049] N,N'-Di-[2-(1-naphthalenesulfonyloxy)phenyl]urea, N,N'-di-[2-(2-naphthalenesulfonyloxy)phenyl]urea,

[0050] N,N'-Di-[2-(p-ethylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-propylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-isopropylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-t-butylbenzenesulfonyloxy)phenyl]urea,

[0051] N,N'-Di-[2-(p-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(m-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(o-methoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(m,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-propoxybenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-butoxybenzenesulfonyloxy)phenyl]urea,

[0052] N,N'-Di-[2-(p-cumylbenzylsulfonyloxy)phenyl]urea, N,N'-di-[2-(p-cumylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(o-phenylbenzenesulfonyloxy)phenyl]urea, N,N'-di-[2-(p-phenylbenzenesulfonyloxy)phenyl]urea,

[0053] N,N'-Di-[2-(p-chlorobenzenesulfonyloxy)phenyl]urea,

[0054] N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(m-toluenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(o-toluenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(p-xylenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(mesitylenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(1-naphthalenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(2-naphthalenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(benzylsulfonyloxy)phenyl]urea, N-[2-(Benzenesulfonyloxy)phenyl]-N'-[2-(ethanesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[2-(m-toluenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[2-(o-toluenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[2-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[2-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[2-(2-naphthalenesulfonyloxy)phenyl]urea,

[0055] N-[2-(p-Toluenesulfonyloxy)phenyl]-N'-[2-(benzylsulfonyloxy)phenyl]urea, N-[2-(p-Toluenesulfonyloxy)phenyl]-N'-[2-(p-methylbenzylsulfonyloxy)phenyl]urea, N-[2-(p-Toluenesulfonyloxy)phenyl]-N'-[2-(p-methoxybenzylsulfonyloxy)phenyl]urea, N-[2-(p-Toluenesulfonyloxy)phenyl]-N'-[2-(methanesulfonyloxy)phenyl]urea, N-[2-(p-Toluenesulfonyloxy)phenyl]-N'-[2-(propanesulfonyloxy)phenyl]urea, N-[2-(p-Toluenesulfonyloxy)phenyl]-N'-[2-(butanesulfonyloxy)phenyl]urea,

[0056] N,N'-Di-[2-(benzylsulfonyloxy)phenyl]urea, N,N'-Di-[2-(benzylsulfonyloxy)-4-methyl-phenyl]urea, N,N'-Di-[2-(phenylethanesulfonyloxy)phenyl]urea, N,N'-Di-[2-(phenylpropanesulfonyloxy)phenyl]urea, N,N'-Di-[2-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0057] N-[2-(benzylsulfonyloxy)phenyl]-N'-[2-(propanesulfonyloxy)phenyl]urea, N-[2-(benzylsulfonyloxy)phenyl]-N'-[2-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0058] N,N'-Di-[2-(methanesulfonyloxy)phenyl]urea, N,N'-di-[2-(methanesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[2-(methanesulfonyloxy)-4-ethyl-phenyl]urea, N,N'-di-[2-(methanesulfonyloxy)-5-methyl-phenyl]urea, N,N'-di-[2-(methanesulfonyloxy)-4,5-dimethyl-phenyl]urea, N,N'-di-[2-(ethanesulfonyloxy)phenyl]urea, N,N'-di-[2-(ethanesulfonyloxy)-4-methyl-phenyl]urea, N,N'-di-[2-(1-propanesulfonyloxy)phenyl]urea, N,N'-di-[2-(2-propanesulfonyloxy)phenyl]urea, N,N'-di-[2-(butanesulfonyloxy)phenyl]urea, N,N'-di-[2-(pentanesulfonyloxy)phenyl]urea, N,N'-di-[2-(hexanesulfonyloxy)phenyl]urea, N,N'-di-[2-(cyclohexanesulfonyloxy)phenyl]urea, N,N'-di-[2-(dodecanesulfonyloxy)phenyl]urea,

[0059] N-[2-(ethanesulfonyloxy)phenyl]-N'-[2-(propanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[2-(hexanesulfonyloxy)phenyl]urea,

[0060] N-[3-(benzenesulfonyloxy)phenyl]-N'-[4-(benzenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[4'-(p-toluenesulfonyloxy)phenyl]urea, N-[3-(m-toluenesulfonyloxy)phenyl]-N'-[4-(m-toluenesulfonyloxy)phenyl]urea, N-[3-(o-toluenesulfonyloxy)phenyl]-N'- [3-(o-toluenesulfonyloxy)phenyl]urea,

[0061] N-[3-(p-Xylene sulfonyloxy)phenyl]-N'-[4-(p-xylene sulfonyloxy)phenyl]urea, N-[3-(m-xylene sulfonyloxy)phenyl]-N'-[4-(m-xylene sulfonyloxy)phenyl]urea, N-[3-(mesitylene sulfonyloxy)phenyl]-N'-[4-(mesitylene sulfonyloxy)phenyl]urea,

[0062] N-[3-(1-Naphthalene sulfonyloxy)phenyl]-N'-[4-(1-naphthalene sulfonyloxy)phenyl]urea, N-[3-(2-naphthalene sulfonyloxy)phenyl]-N'-[3-(2-naphthalene sulfonyloxy)phenyl]urea,

[0063] N-[3-(p-Ethylbenzene sulfonyloxy)phenyl]-N'-[4-(p-ethylbenzene sulfonyloxy)phenyl]urea, N-[3-(p-propylbenzene sulfonyloxy)phenyl]-N'-[4-(p-propylbenzene sulfonyloxy)phenyl]urea, N-[3-(p-isopropylbenzene sulfonyloxy)phenyl]-N'-[4-(p-isopropylbenzene sulfonyloxy)phenyl]urea, N-[3-(p-t-butylbenzene sulfonyloxy)phenyl]-N'-[4-(p-t-butylbenzene sulfonyloxy)phenyl]urea,

[0064] N-[3-(p-Methoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[3-(m-methoxybenzenesulfonyloxy)phenyl]-N'-[4-(m-methoxybenzenesulfonyloxy)phenyl]urea, N-[3-(o-methoxybenzenesulfonyloxy)phenyl]-N'-[4-(o-methoxybenzenesulfonyloxy)phenyl]urea, N-[3-(m,p-dimethoxybenzenesulfonyloxy)phenyl]-N'-[4-(m,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N-[3-(p-ethoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N-[3-(p-propoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-propoxybenzenesulfonyloxy)phenyl]urea, N-[3-(p-butoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-butoxybenzenesulfonyloxy)phenyl]urea,

[0065] N-[3-(p-Cumylbenzylsulfonyloxy)phenyl]-N'-[4-(p-cumylbenzylsulfonyloxy)phenyl]urea, N-[3-(p-cumylbenzenesulfonyloxy)phenyl]-N'-[4-(p-cumylbenzenesulfonyloxy)phenyl]urea, N-[3-(o-phenylbenzenesulfonyloxy)phenyl]-N'-[4-(o-phenylbenzenesulfonyloxy)phenyl]urea, N-[3-(p-phenylbenzenesulfonyloxy)phenyl]-N'-[4-(p-phenylbenzenesulfonyloxy)phenyl]urea,

[0066] N-[3-(p-Chlorobenzenesulfonyloxy)phenyl]-N'-[4-(p-chlorobenzenesulfonyloxy)phenyl]urea,

[0067] N-[3-(benzenesulfonyloxy)phenyl]-N'-[4-(p-toluenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[4-(o-toluenesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[4-(benzenesulfonyloxy)phenyl]urea, N-[3-(benzenesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[3-(p-toluenesulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea,

[0068] N-[3-(benzylsulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea, N-[3-(phenylethanesulfonyloxy)phenyl]-N'-[4-(phenylethanesulfonyloxy)phenyl]urea, N-[3-(phenylpropanesulfonyloxy)phenyl]-N'-[4-(phenylpropanesulfonyloxy)phenyl]urea, N-[3-(p-methoxybenzylsulfonyloxy)phenyl]-N'-[4-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0069] N-[3-(benzylsulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea, N-[3-(benzylsulfonyloxy)phenyl]-N'-[4-(p-methylbenzylsulfonyloxy)phenyl]urea,

[0070] N-[3-(Methanesulfonyloxy)phenyl]-N'-[4-(methanesulfonyloxy)phenyl]urea, N-[3-(ethanesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[3-(1-propanesulfonyloxy)phenyl]-N'-[4-(1-propanesulfonyloxy)phenyl]urea, N-[3-(2-propanesulfonyloxy)phenyl]-N'-[4-(2-propanesulfonyloxy)phenyl]urea, N-[3-(butanesulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea, N-[3-(pentanesulfonyloxy)phenyl]-N'-[4-(pentanesulfonyloxy)phenyl]urea, N-[3-(hexanesulfonyloxy)phenyl]-N'-[4-(hexanesulfonyloxy)phenyl]urea, N-[3-(cyclohexanesulfonyloxy)phenyl]-N'-[4-(cyclohexanesulfonyloxy)phenyl]urea, N-[3-(dodecanesulfonyloxy)phenyl]-N'-[4-(dodecanesulfonyloxy)phenyl]urea,

[0071] N-[3-(Methanesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[3-(methanesulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea,

[0072] N-[2-(Benzenesulfonyloxy)phenyl]-N'-[4-(benzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[4-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(m-toluenesulfonyloxy)phenyl]-N'-[4-(m-toluenesulfonyloxy)phenyl]urea, N-[2-(o-toluenesulfonyloxy)phenyl]-N'-[4-(o-toluenesulfonyloxy)phenyl]urea,

[0073] N-[2-(p-Xylenesulfonyloxy)phenyl]-N'-[4-(p-xylenesulfonyloxy)phenyl]urea, N-[2-(m-xylenesulfonyloxy)phenyl]-N'-[4-(m-xylenesulfonyloxy)phenyl]urea, N-[2-(mesitylenesulfonyloxy)phenyl]-N'-[4-(mesitylenesulfonyloxy)phenyl]urea,

[0074] N-[2-(1-Naphthalenesulfonyloxy)phenyl]-N'-[4-(1-naphthalenesulfonyloxy)phenyl]urea, N-[2-(2-naphthalenesulfonyloxy)phenyl]-N'-[4-(2-naphthalenesulfonyloxy)phenyl]urea,

[0075] N-[2-(p-Ethylbenzenesulfonyloxy)phenyl]-N'-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-Propylbenzenesulfonyloxy)phenyl]-N'-[4-(p-propylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-Isopropylbenzenesulfonyloxy)phenyl]-N'-[4-(p-isopropylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-t-Butylbenzenesulfonyloxy)phenyl]-N'-[4-(p-t-butylbenzenesulfonyloxy)phenyl]urea,

[0076] N-[2-(p-Methoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(m-methoxybenzenesulfonyloxy)phenyl]-N'-[4-(m-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(o-methoxybenzenesulfonyloxy)phenyl]-N'-[4-(o-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(m,p-dimethoxybenzenesulfonyloxy)phenyl]-N'-[4-(m,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-ethoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-propoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-propoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-butoxybenzenesulfonyloxy)phenyl]-N'-[4-(p-butoxybenzenesulfonyloxy)phenyl]urea,

[0077] N-[2-(p-Cumylbenzylsulfonyloxy)phenyl]-N'-[4-(p-cumylbenzylsulfonyloxy)phenyl]urea, N-[2-(p-cumylbenzenesulfonyloxy)phenyl]-N'-[4-(p-cumylbenzenesulfonyloxy)phenyl]urea, N-[2-(o-phenylbenzenesulfonyloxy)phenyl]-N'-[4-(o-phenyl)benzenesulfonyloxyhenyl]urea, N-[2-(p-phenylbenzenesulfonyloxy)phenyl]-N'-[4-(p-phenylbenzenesulfonyloxy)phenyl]urea,

[0078] N-[2-(p-Chlorobenzenesulfonyloxy)phenyl]-N'-[4-(p-chlorobenzenesulfonyloxy)phenyl]urea,

[0079] N-[2-(Ethanesulfonyloxy)phenyl]-N'-[4-(benzenesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[4-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[4-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[4-(o-toluenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl-N'-[4-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[4-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[4-[benzenesulfonyloxy]phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[4-(mesitylenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[4-(1-naphthalenesulfonyloxy)phenyl]urea,

[0080] N-[2-(benzylsulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea, N-[2-(phenylethanesulfonyloxy)phenyl]-N'-[4-(phenylethanesulfonyloxy)phenyl]urea, N-[2-(phenylpropanesulfonyloxy)phenyl]-N'-[4-(phenylpropanesulfonyloxy)phenyl]urea, N-[2-(p-methoxybenzylsulfonyloxy)phenyl]-N'-[4-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0081] N-[2-(Ethanesulfonyloxy)phenyl]-N'-[4-(benzylsulfonyloxy)phenyl]urea, N-[2-(benzylsulfonyloxy)phenyl]-N'-[4-(methanesulfonyloxy)phenyl]urea, N-[2-(benzylsulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea,

[0082] N-[2-(methanesulfonyloxy)phenyl]-N'-[4-(methanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[4-(ethanesulfonyloxy)phenyl]urea, N-[2-(1-propanesulfonyloxy)phenyl]-N'-[4-(1-propanesulfonyloxy)phenyl]urea, N-[2-(2-propanesulfonyloxy)phenyl]-N'-[4-(2-propanesulfonyloxy)phenyl]urea, N-[2-(butanesulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea, N-[2-(pentanesulfonyloxy)phenyl]-N'-[4-(pentanesulfonyloxy)phenyl]urea, N-[2-(hexanesulfonyloxy)phenyl]-N'-[4-(hexanesulfonyloxy)phenyl]urea, N-[2-(cyclohexanesulfonyloxy)phenyl]-N'-[4-(cyclohexanesulfonyloxy)phenyl]urea, N-[2-(dodecanesulfonyloxy)phenyl]-N'-[4-(dodecanesulfonyloxy)phenyl]urea,

[0083] N-[2-(methanesulfonyloxy)phenyl]-N'-[4-(propanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[4-(propanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[4-(butanesulfonyloxy)phenyl]urea,

[0084] N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(benzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(m-toluenesulfonyloxy)phenyl]-N'-[3-(m-toluenesulfonyloxy)phenyl]urea, N-[2-(o-toluenesulfonyloxy)phenyl]-N'-[3-(o-toluenesulfonyloxy)phenyl]urea,

[0085] N-[2-(p-xylenesulfonyloxy)phenyl]-N'-[3-(p-xylenesulfonyloxy)phenyl]urea, N-[2-(m-xylenesulfonyloxy)phenyl]-N'-[3-(m-xylenesulfonyloxy)phenyl]urea, N-[2-(mesitylenesulfonyloxy)phenyl]-N'-[3-(mesitylenesulfonyloxy)phenyl]urea,

[0086] N-[2-(1-naphthalenesulfonyloxy)phenyl]-N'-[3-(1-naphthalenesulfonyloxy)phenyl]urea, N-[2-(2-naphthalenesulfonyloxy)phenyl]-N'-[3-(2-naphthalenesulfonyloxy)phenyl]urea,

[0087] N-[2-(p-ethylbenzenesulfonyloxy)phenyl]-N'-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-propylbenzenesulfonyloxy)phenyl]-N'-[3-(p-propylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-isopropylbenzenesulfonyloxy)phenyl]-N'-[3-(p-isopropylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-t-butylbenzenesulfonyloxy)phenyl]-N'-[3-(p-t-butylbenzenesulfonyloxy)phenyl]urea,

[0088] N-[2-(p-Methoxybenzenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(m-methoxybenzenesulfonyloxy)phenyl]-N'-[3-(m-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(o-methoxybenzenesulfonyloxy)phenyl]-N'-[3-(o-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(m,p-dimethoxybenzenesulfonyloxy)phenyl]-N'-[3-(m,p-dimethoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-ethoxybenzenesulfonyloxy)phenyl]-N'-[3-(p-ethoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-propoxybenzenesulfonyloxy)phenyl]-N'-[3-(p-propoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-butoxybenzenesulfonyloxy)phenyl]-N'-[3-(p-butoxybenzenesulfonyloxy)phenyl]urea,

[0089] N-[2-(p-Cumylbenzylsulfonyloxy)phenyl]-N'-[3-(p-cumylbenzylsulfonyloxy)phenyl]urea, N-[2-(p-cumylbenzenesulfonyloxy)phenyl]-N'-[3-(p-cumylbenzenesulfonyloxy)phenyl]urea, N-[2-(o-phenylbenzenesulfonyloxy)phenyl]-N'-[3-(o-phenylbenzenesulfonyloxy)phenyl]urea, N-[2-(p-phenylbenzenesulfonyloxy)phenyl]-N'-[3-(p-phenylbenzenesulfonyloxy)phenyl]urea,

[0090] N-[2-(p-Chlorobenzenesulfonyloxy)phenyl]-N'-[3-(p-chlorobenzenesulfonyloxy)phenyl]urea,

[0091] N-[2-(ethanesulfonyloxy)phenyl]-N'-[3-(benzenesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(ethanesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(benzylsulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(p-toluenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(o-toluenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(p-ethylbenzenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(p-methoxybenzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[3-(benzenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[3-(mesitylenesulfonyloxy)phenyl]urea, N-[2-(p-toluenesulfonyloxy)phenyl]-N'-[3-(1-naphthalenesulfonyloxy)phenyl]urea,

[0092] N-[2-(benzylsulfonyloxy)phenyl]-N'-[3-(benzylsulfonyloxy)phenyl]urea, N-[2-(phenylethanesulfonyloxy)phenyl]-N'-[3-(phenylethanesulfonyloxy)phenyl]urea, N-[2-(phenylpropanesulfonyloxy)phenyl]-N'-[3-(phenylpropanesulfonyloxy)phenyl]urea, N-[2-(p-methoxybenzylsulfonyloxy)phenyl]-N'-[3-(p-methoxybenzylsulfonyloxy)phenyl]urea,

[0093] N-[2-(ethanesulfonyloxy)phenyl]-N'-[3-(benzenesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(methanesulfonyloxy)phenyl]urea, N-[2-(benzenesulfonyloxy)phenyl]-N'-[3-(butanesulfonyloxy)phenyl]urea,

[0094] N-[2-(methanesulfonyloxy)phenyl]-N'-[3-(methanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[3-(ethanesulfonyloxy)phenyl]urea, N-[2-(1-propanesulfonyloxy)phenyl]-N'-[3-(1-propanesulfonyloxy)phenyl]urea, N-[2-(2-propanesulfonyloxy)phenyl]-N'-[3-(2-propanesulfonyloxy)phenyl]urea, N-[2-(butanesulfonyloxy)phenyl]-N'-[3-(butanesulfonyloxy)phenyl]urea, N-[2-(pentanesulfonyloxy)phenyl]-N'-[3-(pentanesulfonyloxy)phenyl]urea, N-[2-(hexanesulfonyloxy)phenyl]-N'-[3-(hexanesulfonyloxy)phenyl]urea, N-[2-(cyclohexanesulfonyloxy)phenyl]-N'-[3-(cyclohexanesulfonyloxy)phenyl]urea, N-[2-(dodecanesulfonyloxy)phenyl]-N'-[3-(dodecanesulfonyloxy)phenyl]urea,

[0095] N-[2-(methanesulfonyloxy)phenyl]-N'-[3-(propanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[3-(propanesulfonyloxy)phenyl]urea, N-[2-(ethanesulfonyloxy)phenyl]-N'-[3-(butanesulfonyloxy)phenyl]urea, and the like.

[0096] <Process for producing the compound represented by the general formula (1)> The compound represented by the general formula (1) above can be synthesized by reacting the compound represented by the following general formula (4) with the aromatic amine compound represented by the following general formula (5). In addition, the compound represented by the general formula (1) above can be synthesized by reacting the compound represented by the following general formula (6) with the aromatic amine compound represented by the following general formula (7).

[0097] [Chemical formula]

[0098] [Chemical formula]

[0099] However, in the general formulas (4) and (5), R1 represents an alkyl group or an aryl group. A1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A plurality of A1 may be the same or different. R2 is a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms, an unsubstituted or 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 an aralkyl group having 7 to 12 carbon atoms substituted with a halogen atom or an aryl group having 6 to 12 carbon atoms.

[0100] [Chemical formula]

[0101] [Chemical formula] However, in the general formulas (6) and (7), R1 represents an alkyl group or an aryl group, R represents an alkyl group, and n represents an integer of 0 to 3.

[0102] For example, it can be synthesized by the following method. [Step 1] 3-[(R) n-PhSO3]-Ph-NH2 / deacidifying agent + XCOOR1 → 3-[(R) n -PhSO3]-Ph-NHCOOR1 + HX·deacidifying agent [Step 2] 3-[(R) n -PhSO3]-Ph-NHCOOR1 + 3-[(R) n -PhSO3]-Ph-NH2 / base → 3-{[(R) n -PhSO3]-Ph-NH}2=CO + R1OH However, in the above formula, R1 represents an alkyl group or an aryl group, R represents an alkyl group, Ph represents a phenyl group, and n represents an integer from 0 to 3.

[0103] XCOOR1 used in Step 1 of the above synthesis method is a halogenated carbonate ester or a dicarbonate ester, X is chlorine, bromine, OMe, OEt, OPro or OPh, and R1 is a Me group, Et group, Pro group, Ph group, etc. The Me group represents a methyl group, the Et group represents an ethyl group, the Pro group represents a propyl group, and pH represents a phenyl group. Particularly, methyl monochlorocarbonate, ethyl monochlorocarbonate, phenyl monochlorocarbonate, diethyl carbonate, and diphenyl carbonate are preferred.

[0104] The alkyl groups of R1 and R are the same as the alkyl group of R.

[0105] During the reaction, organic bases and inorganic bases are used as the deacidifying agent and the base. Examples of the inorganic base include LiOH, NaOH, KOH, NaHCO3, KHCO3, Na2CO3, K2CO3, MeONa, EtONa, etc. Examples of the organic base include organic bases such as trimethylamine, triethylamine, tributylamine, pyridine, N,N-dimethylpyridine, 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU). Preferably, they are K2CO3, triethylamine, pyridine, N,N-dimethylpyridine, 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU).

[0106] 3-[(R) n -PhSO3]-Ph-NH2 can also be synthesized by directly O-sulfonylating 3-hydroxyaniline, and can also be easily obtained by reducing the nitro group after O-sulfonylating the nitrophenol compound.

[0107] 3-[(R) n Examples of 3-[(R)-PhSO3]-Ph-NH2 include 3-benzenesulfonyloxyaniline, 3-(p-toluene)sulfonyloxyaniline, 3-(m-toluene)sulfonyloxyaniline, 3-(o-toluene)sulfonyloxyaniline, 3-(p-xylene)sulfonyloxyaniline, 3-mesitylenesulfonyloxyaniline, etc. Preferably, they are 3-benzenesulfonyloxyaniline and 3-(p-toluene)sulfonyloxyaniline.

[0108] Generally, an aprotic solvent can be used as the reaction solvent, and the reaction is carried out at a reaction temperature of 0 °C to 180 °C. In the present invention, the reaction temperature is, for example, in the range of 0 °C to 180 °C, but preferably 10 °C to 100 °C. According to the boiling point of the solvent and the stability of the reaction product, the solvent and the reaction temperature are preferably selected.

[0109] Examples of the aprotic solvent include aromatic hydrocarbons such as benzene, toluene, xylene, and mesitylene; halogenated hydrocarbons such as dichloromethane, chloroform, dichloroethane, and chlorobenzene; acetate esters such as ethyl acetate, propyl acetate, butyl acetate, phenyl acetate, and benzyl acetate; ether compounds such as diethyl ether, dimethoxyethane, diethoxyethane, diethylene glycol dimethyl ether, dioxane, tetrahydrofuran, and anisole; ketone compounds such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; acetonitrile, dimethylsulfonamide, dimethyl sulfoxide, dimethylimidazolidine, etc.

[0110] In Step 2, the 3-[(R) n-PhSO3]-Ph-NHCOOR and 3-[(R) n -PhSO3]-Ph-NH2 is carried out by reacting it in the presence of a base. For the base, reaction solvent, and reaction temperature used in Step 2, the above reaction conditions used in Step 1 can be used.

[0111] Also, in order to simplify the reaction operation, it is also possible to simultaneously carry out Step 1 and Step 2 by using 2 equivalents or more of 3-[(R) n -PhSO3]-Ph-NH2.

[0112] To introduce a urea group, various urea group introduction methods have been proposed. For example, methods for forming a urea group from the introduction of carbon monoxide using metal catalysts such as palladium and molybdenum, or carbonylbisimidazole, have been proposed, but the catalysts and reagents are expensive, the operations are complicated, and they are not necessarily industrial.

[0113] The N,N'-diphenylurea derivatives represented by the above general formulas (1) to (3) can also be synthesized by reacting dihydroxydiphenylurea represented by the following general formula (8) with a sulfonating agent represented by the following general formula (9) in the presence of an aprotic solvent. In particular, when synthesizing a symmetric compound, after synthesizing dihydroxydiphenylurea, the above production method of O-sulfonylation is the most versatile and economical.

[0114]

Chemical formula

[0115]

Chemical formula

[0116] In addition, by selecting a reaction solvent, the above production method enables the production process of dihydroxydiphenylurea to be carried out in a smooth slurry state, and has industrial advantages such as being able to continuously carry out the next-step reaction without isolating dihydroxydiphenylurea.

[0117] The N,N'-diphenylurea derivative represented by the above general formulas (1) to (3) can also be synthesized by reacting an aminophenol compound represented by the following general formula (8-1) with urea in the presence of an aprotic solvent, and then reacting with a sulfonating agent represented by the above general formula (9). By the step of reacting an aminophenol compound represented by the general formula (8-1) with urea in the presence of an aprotic solvent, the production process of dihydroxydiphenylurea proceeds smoothly, and the reaction can be carried out in a slurry state. Furthermore, it is possible to continuously carry out the step of reacting with a sulfonating agent represented by the general formula (9) without isolating dihydroxydiphenylurea.

[0118]

Chemical formula

[0119] The reaction for synthesizing dihydroxydiphenylurea from aminophenol and urea is carried out in an aprotic solvent at a reaction temperature of 80°C to 200°C. Preferably, it is 125 to 180°C.

[0120] Aminophenols include 2-aminophenol, 3-aminophenol, 4-aminophenol, 2-amino-5-methylphenol, 2-amino-4-methylphenol, 2-amino-6-methylphenol, 2-amino-4,5-dimethylphenol, 2-methyl-5-aminophenol, 3-methyl-5-aminophenol, 2,3-dimethyl-5-aminophenol, 2,4-dimethyl-5-aminophenol, 2,6-dimethyl-5-aminophenol, 3,4-dimethyl-5-aminophenol, 2-methyl-4-aminophenol, 3-methyl-4-aminophenol, 2,6-dimethyl-4-aminophenol, and the like.

[0121] Examples of aprotic solvents include hydrocarbons such as tetralin, benzene, toluene, xylene, and mesitylene; halogenated hydrocarbons such as trichloroethylene, chlorobenzene, and dichlorobenzene; acetate esters such as ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, isoamyl acetate, amyl acetate, hexyl acetate, phenyl acetate, and benzyl acetate; ether compounds such as diethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, dioxane, tetrahydrofuran, and anisole; ketone compounds such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, acetophenone, and benzophenone; tertiary amines such as tributylamine, pyridine, dimethylpyridine, and diazabicycloundecene; and aprotic polar solvents such as acetonitrile, benzonitrile, dimethylformamide, dimethyl sulfoxide, dimethylimidazolidine, and dimethylacetamide. These solvents may be used in combination of two or more.

[0122] Preferred solvents are aprotic non-aqueous solvents having a boiling point of 110°C or higher, and particularly preferred are acetate esters having a boiling point of butyl acetate or higher, and aromatic hydrocarbons such as toluene and xylene. As a method for post-reaction treatment, there are (1) a method of isolating dihydroxydiphenylurea by cooling and filtering the reaction solution and subjecting it to the next reaction, and (2) a method of cooling to the next reaction temperature and directly subjecting the reaction solution to the next reaction without isolating dihydroxydiphenylurea.

[0123] Next, the O-sulfonation reaction of dihydroxydiphenylurea can be carried out by dropping a sulfonating agent into a reaction solution composed of dihydroxydiphenylurea, a deacidifying agent, and an aprotic solvent. Alternatively, it may be carried out by dropping a deacidifying agent into a reaction solution composed of dihydroxydiphenylurea, a sulfonating agent, and an aprotic solvent. The reaction temperature of the O-sulfonation reaction is carried out in the range of 0 °C to 200 °C in the presence of a deacidifying agent, and preferably carried out at 10 °C to 150 °C.

[0124] O-sulfonation is carried out using a sulfonyl halide or the like. As the sulfonyl halide, a sulfonyl chloride is preferred. For example, ethanesulfonyl chloride, ethanesulfonyl chloride, n-propanesulfonyl chloride, i-propanesulfonyl chloride, butanesulfonyl chloride, benzylsulfonyl chloride, benzenesulfonyl chloride, p-toluenesulfonyl chloride, o-toluenesulfonyl chloride, p-xylenesulfonyl chloride, mesitylenesulfonyl chloride, p-ethylbenzenesulfonyl chloride, p-methoxybenzenesulfonyl chloride, p-chlorobenzenesulfonyl chloride, 1-naphthalenesulfonyl chloride, 2-naphthalenesulfonyl chloride, etc. can be mentioned.

[0125] Examples of the deacidifying agent include organic bases such as trimethylamine, triethylamine, tributylamine, pyridine, and dimethylaminopyridine; inorganic bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, potassium hydrogen carbonate, sodium hydrogen carbonate, sodium carbonate, potassium carbonate, and calcium carbonate; and bases such as sodium hydride, sodium methoxide, and sodium ethoxide.

[0126] The solvent used in the O-sulfonation step of dihydroxydiphenylurea is an aprotic solvent, and in particular, acetate esters such as butyl acetate, isoamyl acetate, amyl acetate, and hexyl acetate used in the previous step, and aromatic hydrocarbons such as toluene, xylene, and mesitylene are particularly preferred. As the reaction solvent, the solvent used in the previous step may be used alone, or as a mixed solvent of two or more kinds, or as a two-phase solvent system of water and a water-insoluble aprotic solvent.

[0127] When carrying out the reaction, the solvent and reaction temperature are preferably selected according to the reaction method in consideration of the boiling point of the solvent, the physical properties of the sulfonating agent, and the stability of the reaction product. After the reaction is completed, water is added to the reaction solution to wash away the deacidifying agent and the like by water washing. Furthermore, when high-purity quality is required, aromatic hydrocarbons such as benzene and toluene, acetate esters such as ethyl acetate and isoamyl acetate, and alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol may be used for crystal washing and recrystallization operations.

[0128] The content of the color former is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 1 to 20 parts by mass, more preferably 2 to 10 parts by mass, based on 1 part by mass of the leuco dye.

[0129] <<Leuco dye>> The leuco dye is not particularly limited and can be appropriately selected according to the purpose from those used in thermal recording media. For example, leuco compounds of dyes such as triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes are preferably mentioned.

[0130] The leuco dye is not particularly limited and can be appropriately selected according to the purpose. For example, 3,3-bis(p-dimethylaminophenyl)-phthalide, 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (alias crystal violet lactone), 3,3-bis(p-dimethylaminophenyl)-6-diethylaminophthalide, 3,3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3,3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7-dimethylfluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzofluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-(N-p-tolyl-N-ethylamino)-6-methyl-7-anilinofluoran, 2-{N-(3'-trifluoromethylphenyl)amino}-6-diethylaminofluoran, 2-{3,6-bis(diethylamino)-9-(o-chloroanilino)xanthyl benzoic acid lactam}, 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-di-n-butylamino-7-o-chloroanilino)fluoran, 3-N-methyl-N,n-amylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-(N,N-diethylamino)-5-methyl-7-(N,(N-dibenzylamino) fluoran, benzoyl leucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-3'-methoxy-benzoindolino-spiropyran, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'chlorophenyl) phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy-5'-nitrophenyl) phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3-(2'-methoxy-4'-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'-methylphenyl) phthalide, 3-(N-ethyl-N-tetrahydrofurfuryl) amino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-(2-ethoxypropyl) amino-6-methyl-7-anilinofluorane, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluorane, 3-morpholino-7-(N-propyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-benzyl-trifluoromethylanilino) fluorane, 3-pyrrolidino-7-(di-p-chlorophenyl) methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino) fluorane, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamino) fluorane, 3-diethylamino-7-(o-methoxycarbonylphenylamino) fluorane, 3-diethylamino-5-methyl-7-(α-phenylethylamino) fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3-(N-methyltoluidino)-7-(p-n-butylanilino) fluorane, 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3,6-bis(dimethylamino) fluorene spiro(9,3')-6'-dimethylaminophthalide, 3-(N-benzyl-N-cyclohexylamino)-5,6-benzo-7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitylidino-4',5'-benzofluorane, 3-N-methyl-N-isopropyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-isoamyl-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-(2',4'-dimethylanilino)fluorane, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-(α-phenylethylamino)fluorane, 3-(N-ethyl-p-toluidino)-7-(α-phenylethylamino)fluorane, 3-diethylamino-7-(o-methoxycarbonylphenylamino)fluorane, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluorane, 3-diethylamino-7-piperidinofluorane, 2-chloro-3-(N-methyltoluidino)-7-(p-N-butylanilino)fluorane, 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-dimethylaminophthalide, 3-(N-benzyl-N-cyclohexylamino)-5,6-benzo-7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N-(-2-ethoxypropyl)amino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitylidino-4',5'-benzofluorane, 3-p-dimethylaminophenyl)-3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}phthalide, 3-(p-dimethylaminophenyl)-3-{1,1-bis(p-dimethylaminophenyl)ethylene-2-yl}-6-dimethylaminophthalide, 3-(p-dimethylaminophenyl)-3-(1-p-dimethylaminophenyl-1-phenylethylene-2-yl)phthalide, 2-ortho-chloroanilino-6-diethylaminofluoran, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-(N-ethyl-N-p-tolyl)aminofluoran, 3-N-cyclohexyl-N-methylamino-6-methyl-7-anilinofluoran, 3-(p-dimethylaminophenyl)-3-(1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl)-6-dimethylaminophthalide, 3-(4'-dimethylamino-2'-methoxy)-3-(1"-p-dimethylaminophenyl-1"-p-chlorophenyl-1",3"-butadien-4"-yl)benzophthalide, 3-(4'-dimethylamino-2'-benzyloxy)-3-(1"-p-dimethylaminophenyl-1"-phenyl-1",3"-butadien-4"-yl)benzophthalide, 3-dimethylamino-6-dimethylamino-fluorene-9-spiro-3'-(6'-dimethylamino)phthalide, 3,3-bis(2-(p-dimethylaminophenyl)-2-p-methoxyphenyl)ethenyl)-4,5,6,7-tetrachlorophthalide, 3-bis{1,1-bis(4-pyrrolidinophenyl)ethylene-2-yl}-5,6-dichloro-4,7-dibromophthalide, bis(p-dimethylaminostyryl)-1-naphthalenesulfonylmethane, bis(p-dimethylaminostyryl)-1-p-tolylsulfonylmethane, 6'-(diethylamino)-2'-(2-fluoroanilino)spiro[phthalide-3,9'-xanthene], and the like. These may be used alone or in combination of two or more.,

[0131] The content of the electron-donating compound is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, based on the total amount of the heat-sensitive recording layer.,

[0132] <<Styrene-acrylic resin>> As the styrene-acrylic resin, those synthesized as appropriate may be used, or commercially available products may be used. As the synthesis method, for example, it can be produced by emulsion polymerization, dispersion polymerization, suspension polymerization, pulverization or solution / bulk polymerization, and subsequent post-emulsification. Examples of the commercially available products include trade names: PDX-7357, PDX-7616A, PDX-7732, PDX-7741, PDX-7787, PDX-7734, PDX-7777, PDX-7615, HPD-71, HPD-196 (all manufactured by BASF), trade names: EK-15, EK-61 (both manufactured by Siden Chemical Co., Ltd.), trade names: A-2092, XK-110 (both manufactured by DSM Coating Resins), etc.

[0133] The styrene-acrylic resin is preferably a resin emulsion. A resin emulsion refers to a state in which resin particles are dispersed in an aqueous medium or the like, and it does not matter whether the resin particles are solid or liquid. Note that the aqueous medium refers to one containing water or a hydrophilic solvent as a component.

[0134] Examples of the method for dispersing the resin particles in the aqueous medium include a forced emulsification method using a dispersant and a self-emulsification method using a resin having an anionic group. In the case of the forced emulsification method, since the dispersant may remain in the image formed by the ink and there is a risk of reducing the intensity of the image, it is preferable to use the self-emulsification method.

[0135] The content of the styrene-acrylic resin is not particularly limited and can be appropriately selected according to the purpose. However, with respect to the entire heat-sensitive recording layer, it is preferably 1.0% by mass or more and 50.0% by mass or less, more preferably 10.0% by mass or more and 50.0% by mass or less, and still more preferably 20.0% by mass or more and 40.0% by mass or less.

[0136] Other resins other than the styrene-acrylic resin can be added as needed. Examples of the other resins include polyvinyl alcohol resins, starch or its derivatives; cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose; water-soluble polymers such as sodium polyacrylate, polyvinyl pyrrolidone, acrylamide-acrylic acid ester copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, alkali salt of styrene-maleic anhydride copolymer, alkali salt of isobutylene-maleic anhydride copolymer, polyacrylamide, sodium alginate, gelatin, and casein; emulsions such as polyvinyl acetate resin, polyurethane resin, polyacrylic acid, polyacrylic acid ester, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, and ethylene-vinyl acetate copolymer; and latexes such as styrene-butadiene copolymer and styrene-butadiene-acrylic copolymer. These may be used alone or in combination of two or more. When the other resin is contained, the content of the other resin is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, based on 100 parts by mass of the styrene-acrylic resin, from the viewpoint of heat resistance in water.

[0137] <<Photothermal conversion material>> The photothermal conversion material is a material that absorbs laser light and converts it into heat, and can be roughly classified into inorganic materials and organic materials. Examples of the inorganic materials include at least one of carbon black, metal borides, and particles of metal oxides such as Ge, Bi, In, Te, Se, and Cr. Among these, materials with large absorption of light in the near-infrared wavelength region and little absorption of light in the visible wavelength region are preferred, and the metal borides and metal oxides are more preferred. Examples of the metal borides and metal oxides include at least one selected from 6 borides, tungsten oxide compounds, antimony tin oxide (ATO), indium tin oxide (ITO), and zinc antimonate. Examples of the hexaboride include LaB6, CeB6, PrB6, NdB6, GdB6, TbB6, DyB6, HoB6, YB6, SmB6, EuB6, ErB6, TmB6, YbB6, LuB6, SrB6, CaB6, (La,Ce)B6, and the like. Examples of the tungsten oxide compound include fine particles of tungsten oxide represented by the general formula: WyOz (where W is tungsten, O is oxygen, and 2.2 ≤ z / y ≤ 2.999), or fine particles of composite tungsten oxide represented by the general formula: MxWyOz (where M is one or more elements selected from H, He, an alkali metal, an alkaline earth metal, a rare earth element, Mg, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Tl, Si, Ge, Sn, Pb, Sb, B, F, P, S, Se, Br, Te, Ti, Nb, V, Mo, Ta, Re, Be, Hf, Os, Bi, and I; W is tungsten, O is oxygen, 0.001 ≤ x / y ≤ 1, and 2.2 ≤ z / y ≤ 3.0), as described in, for example, Pamphlet of International Publication No. 2005 / 037932, Japanese Patent Application Laid-Open No. 2005-187323, and the like. Among these, cesium-containing tungsten oxide is particularly preferable because of its large absorption in the near-infrared region and small absorption in the visible region. Among antimony tin oxide (ATO), indium tin oxide (ITO), and zinc antimonate, ITO is particularly preferable because of its large absorption in the near-infrared region and small absorption in the visible region. These are formed in layers by a vacuum deposition method or by adhering particulate materials with a resin or the like. As the organic material, various dyes can be appropriately used according to the light wavelength to be absorbed. When a semiconductor laser is used as the light source, a near-infrared absorbing dye having an absorption peak around 600 nm to 1,200 nm is used. Specifically, examples include cyanine dyes, quinone dyes, quinoline derivatives of indonaphthol, phenylenediamine-based nickel complexes, phthalocyanine-based dyes, and the like. The photothermal conversion material may be used alone or in combination of two or more. The above-mentioned photothermal conversion material may be contained in the heat-sensitive recording layer or in a layer other than the heat-sensitive recording layer. When it is contained in a layer other than the heat-sensitive recording layer, it is preferable to provide a photothermal conversion layer adjacent to the heat-sensitive recording layer. The content of the above-mentioned photothermal conversion material is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.3% by mass or more and 5% by mass or less, based on the heat-sensitive recording layer.

[0138] <<Other components>> Examples of the above-mentioned other components include auxiliary additives, thermofusible substances, lubricants, fillers, ultraviolet absorbers, antioxidants, sensitizers, light stabilizers, crosslinking agents, and the like.

[0139] As the above-mentioned auxiliary additive, for example, various hindered phenol compounds or hindered amine compounds that are electron-accepting but have relatively little coloring ability may be added. Examples of the above-mentioned auxiliary additive include 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-2-methylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 4,4'-thiobis(6-tert-butyl-2-methylphenol), tetrabromobisphenol A, tetrabromobisphenol S, 4,4”thiobis(2-methylphenol), 4,4'-thiobis(2-chlorophenol), tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, and the like. These may be used alone or in combination of two or more.

[0140] -Thermofusible substance- Examples of the heat-fusible substance include fatty acids such as stearic acid and behenic acid; fatty acid amides such as stearic acid amide and palmitic acid amide; fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate, and zinc behenate; p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, glycol carbonate, dibenzyl terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4-dibenzyloxynaphthalene, 1,2-diphenoxyethane, 1,2-bis(3-methylphenoxy)ethane, 1,2-bis(4-methylphenoxy)ethane, 1,4-diphenoxy-2-butene, 1,2-bis(4-methoxyphenylthio)ethane, dibenzoylmethane, 1,4-diphenylthiobutane, 1,4-diphenylthio-2-butene, 1,3-bis(2-vinyloxyethoxy)benzene, 1,4-bis(2-vinyloxyethoxy)benzene, p-(2-vinyloxyethoxy)biphenyl, p-aryloxybiphenyl, p-propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulfide, 1,1-diphenylethanol, 1,1-diphenylpropanol, p-benzyloxybenzyl alcohol, 1,3-phenoxy-2-propanol, N-octadecylcarbamoyl-p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, 1,2-bis(4-methoxyphenoxy)propane, 1,5-bis(4-methoxyphenoxy)-3-oxapentane, dibenzyl oxalate, bis(4-methylbenzyl) oxalate, bis(4-chlorobenzyl) oxalate, and the like. These may be used alone or in combination of two or more.

[0141] -Lubricant- Examples of the lubricant include higher fatty acids or their metal salts, higher fatty acid amides, higher fatty acid esters, animal waxes, vegetable waxes, mineral waxes, petroleum waxes, synthetic waxes, etc. These may be used alone or in combination of two or more.

[0142] -Filler- Examples of the filler include inorganic fine powders such as calcium carbonate, silica, zinc oxide, titanium oxide, zirconium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium, surface-treated silica, etc.; organic fine powders such as urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene resin, vinylidene chloride resin, etc. These may be used alone or in combination of two or more. The content of the filler is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 0.4 parts by mass or less, more preferably 0.2 parts by mass or less, based on 1 part by mass of the binder resin.

[0143] -Crosslinking agent- The crosslinking agent is not particularly limited and can be appropriately selected according to the purpose. Examples include glyoxal derivatives, methylol derivatives, epichlorohydrin, polyamide epichlorohydrin, epoxy compounds, aziridine compounds, hydrazine, hydrazide derivatives, oxazoline derivatives, carbodiimide derivatives, etc. These may be used alone or in combination of two or more.

[0144] -UV absorber- The UV absorber is not particularly limited and can be appropriately selected according to the purpose. Examples include salicylic acid-based UV absorbers, benzophenone-based UV absorbers, benzotriazole-based UV absorbers, etc. Examples of the ultraviolet absorber include phenyl salicylate, p-tert-butylphenyl salicylate, p-octylphenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis(2-methoxy-4-hydroxy-5-benzoylphenyl)methane, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-{2'-hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidomethyl)-5'-methylphenyl}benzotriazole, 2,2'-methylenebis{4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazol-2-yl)phenol}, 2-(2'-hydroxy-5'-methacryloxyphenyl)-2H-benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, etc. These may be used alone or in combination of two or more.

[0145] <Support> Regarding the substrate, there are no particular restrictions on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose. Examples of the shape include a flat plate shape and a sheet shape. The structure may be a single-layer structure or a laminated structure. The size can be appropriately selected according to the size of the thermal recording medium, etc.

[0146] As the substrate, for example, in addition to ordinary paper, synthetic paper, or plastic films such as polyethylene, transparent polyethylene terephthalate, polypropylene, and vinyl chloride can be used. When using these plastic films, surface treatments such as mat treatment and corona treatment may be performed on the surface of the substrate to improve the fixing property of the coating liquid. Among these, biaxially stretched polyethylene terephthalate sheets, etc. are excellent in terms of strength, heat resistance, dimensional stability, etc., and are preferable. Furthermore, white opaque films or foamed sheets formed by adding white raw materials or fillers to these can also be used. Also, laminates of the above materials can be used, and typically, laminates of cellulose fibers and synthetic paper, cellulose fibers and plastic films, or plastic films and synthetic paper can be mentioned. It is preferable that the substrate is a transparent film in applications in the POS field for fresh food, bento, prepared foods, etc. because the contents can be visually recognized. Here, transparent means that there is no particular problem as long as the haze (turbidity), which is an index related to the transparency of the film, is about 10% or less, but 5% or less is more preferable to achieve the object of the present invention. The average thickness of the substrate can be arbitrarily selected as needed. From the viewpoints of transparency and ease of processing, it is preferably 3 μm or more and 500 μm or less, and more preferably 10 μm or more and 100 μm or less. If the average thickness of the substrate is less than 3 μm, the strength is insufficient, and if it exceeds 500 μm, the transparency decreases and the stiffness becomes too high, resulting in poor processability.

[0147] <Protective layer> The protective layer contains a binder resin and a crosslinking agent, and may further contain other components as required. The protective layer is preferably provided on the heat-sensitive recording layer.

[0148] There are no particular restrictions on the binder resin, and it can be appropriately selected according to the purpose. For example, acrylic resins, polyvinyl alcohol resins, starch or its derivatives; cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose; water-soluble polymers such as sodium polyacrylate, polyvinylpyrrolidone, acrylamide-acrylic acid ester copolymer, styrene-acrylic copolymer, acrylamide-acrylic acid ester-methacrylic acid terpolymer, alkali salt of styrene-maleic anhydride copolymer, alkali salt of isobutylene-maleic anhydride copolymer, polyacrylamide, sodium alginate, gelatin, and casein; emulsions such as polyvinyl acetate, polyurethane, polyacrylic acid, polyacrylic acid ester, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, and ethylene-vinyl acetate copolymer; latexes such as styrene-butadiene copolymer and styrene-butadiene-acrylic copolymer. These may be used alone or in combination of two or more.

[0149] There are no particular restrictions on the crosslinking agent, and it can be appropriately selected according to the purpose. For example, glyoxal derivatives, methylol derivatives, epichlorohydrin, polyamide epichlorohydrin, epoxy compounds, aziridine compounds, hydrazine, hydrazide derivatives, oxazoline derivatives, carbodiimide derivatives, etc. These may be used alone or in combination of two or more.

[0150] Also, it is preferable to contain a pigment (filler) in the protective layer as needed. Examples of the pigment used in the protective layer include inorganic pigments such as zinc oxide, calcium carbonate, barium sulfate, titanium oxide, lithopone, talc, waxstone, kaolin, aluminum hydroxide, and calcined kaolin, and organic pigments such as crosslinked polystyrene resin, urea resin, silicone resin, crosslinked polymethyl methacrylate resin, and melamine-formaldehyde resin. In addition to the above resins, water resistance agents, and pigments, auxiliary additive components conventionally used, such as surfactants, thermofusible substances, lubricants, and pressure color development inhibitors, can be used in combination in the protective layer.

[0151] The protective layer is not particularly limited and can be formed by a generally known method. The average thickness of the protective layer is not particularly limited and can be appropriately selected according to the purpose, but is preferably 0.5 μm or more and 5 μm or less, and more preferably 1 μm or more and 3 μm or less.

[0152] <Printing layer> The printing layer is printed with ink or the like and has various colors, materials, and thicknesses, and forms the background of the image printed on the thermal recording layer. By providing the printing layer, it is possible to describe product names, manufacturing company names, ingredient labels, etc. before product packaging, and excellent design can be imparted to the product. The printing layer is preferably provided on any one of the thermal recording layer, between the support and the thermal recording layer, and on the surface of the support opposite to the thermal recording layer.

[0153] The printing layer contains a coloring material, a binder resin, and a solvent, and further contains other components as needed. The coloring material is not particularly limited and can be appropriately selected according to the purpose, and a pigment or a dye can be used.

[0154] As the binder resin and the other components, the same ones as those of the thermal recording layer can be used.

[0155] The printing layer is formed by gravure printing, flexographic printing, offset printing, UV printing, inkjet printing, or the like.

[0156] The average thickness of the printing layer is not particularly limited and can be appropriately selected according to the purpose, but is preferably 0.05 μm or more and 4 μm or less, and more preferably 0.1 μm or more and 2 μm or less.

[0157] <Other Layers> The other layers are not particularly limited and can be appropriately selected according to the purpose, and examples include a back layer, an underlayer, a heat-seal layer, and the like.

[0158] -Back Layer- The back layer can be provided on the surface of the support on the side where the thermosensitive recording layer is not provided, if necessary. The back layer contains a filler and a binder resin, and further contains other components such as a lubricant and a coloring pigment, if necessary. As the filler, for example, an inorganic filler or an organic filler can be used. Examples of the inorganic filler include carbonates, silicates, metal oxides, sulfuric compounds, and the like. Examples of the organic filler include silicone resins, cellulose, epoxy resins, nylon resins, phenol resins, polyurethane resins, urea resins, melamine resins, polyester resins, polycarbonate resins, styrene resins, acrylic resins, polyethylene resins, formaldehyde resins, polymethyl methacrylate resins, and the like. The binder resin is not particularly limited and can be appropriately selected according to the purpose. For example, the same binder resin as that of the thermosensitive recording layer can be used. The average thickness of the back layer is not particularly limited and can be appropriately selected according to the purpose, but is preferably 0.1 μm or more and 20 μm or less, and more preferably 0.3 μm or more and 10 μm or less.

[0159] -Underlayer- The underlayer is not particularly limited and can be appropriately selected according to the purpose. However, it preferably contains a binder resin and thermoplastic hollow resin particles, and further contains other components as required.

[0160] The thermoplastic hollow resin particles have a thermoplastic resin as a shell and contain air or other gases inside, and are minute hollow particles that are already in a foamed state.

[0161] The average particle diameter (outer particle diameter) of the thermoplastic hollow resin particles is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 0.2 μm or more and 20 μm or less, and more preferably 2 μm or more and 5 μm or less. If the average particle diameter is less than 0.2 μm, it is technically difficult to make it hollow, and the role of the undercoat layer becomes insufficient. On the other hand, if the average particle diameter is more than 20 μm, the smoothness of the surface after coating and drying decreases, so the coating of the thermal recording layer becomes uneven, and a larger amount of the thermal recording layer forming liquid than necessary must be applied to make it uniform.

[0162] The hollow ratio of the thermoplastic hollow resin particles is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 50% to 95%, and more preferably 80% to 95%. If the hollow ratio is less than 30%, the heat insulation is insufficient, so the thermal energy from the thermal head is released outside the thermal recording medium through the support, and the effect of improving the sensitivity becomes insufficient. Here, the hollow ratio refers to the ratio of the outer diameter to the inner diameter (diameter of the hollow part) of the hollow particles, and is represented by the following formula. Hollow ratio (%) = (inner diameter of hollow particle / outer diameter of hollow particle) × 100

[0163] The thermoplastic hollow resin particles have a thermoplastic resin as the shell as described above. The thermoplastic resin is not particularly limited and can be appropriately selected according to the purpose. For example, styrene-acrylic resin, polystyrene resin, acrylic resin, polyethylene resin, polypropylene resin, polyacetal resin, chlorinated polyether resin, polyvinyl chloride resin, copolymer resin mainly composed of vinylidene chloride and acrylonitrile, etc. can be mentioned. Among these, styrene-acrylic resin and copolymer resin mainly composed of vinylidene chloride and acrylonitrile are preferable in that they have a high hollowness, a small variation in particle diameter, and are suitable for blade coating.

[0164] The coating amount of the plastic hollow particles is not particularly limited and can be appropriately selected according to the purpose. However, in terms of maintaining sensitivity and coating uniformity, 1 g to 3 g is required per 1 m of the support. 2 If it is less than 1 g / m, sufficient sensitivity cannot be obtained. Also, if it exceeds 3 g / m, a decrease in layer binding property occurs. 2 2 -Heat-sealing layer-

[0165] Since the heat-sealing layer is formed by laminating a film of LDPE (low-density polyethylene) used as a sealant, it can be welded by heating the heat-sealing layers in a state where they are in close contact with each other. Utilizing this property, a packaging sheet formed in a bag shape can be sealed, that is, heat-sealed, by heating it in a similar state. Therefore, as long as it has the property of being heat-sealable, that is, a substance having heat-sealing property, the heat-sealing layer can be formed without being limited to LDPE. ​​As the substance having heat sealability, for example, films such as HDPE (high-density polyethylene), CPP (cast polypropylene), OPP (biaxially oriented polypropylene), and EVA (ethylene-vinyl acetate copolymer) are preferably used, but polyolefin resins such as polyethylene and polypropylene; vinyl acetate-based resins such as ethylene-vinyl acetate copolymer (such as olefin-vinyl acetate copolymer); acrylic resins such as ethylene-(meth)acrylic acid copolymer and ionomer [such as olefin-(meth)acrylic acid copolymer or its metal crosslinked product] etc. may also be used. Further, it may be formed using a known heat sealable adhesive. In addition, since the packaged product can be seen, it is preferable to use a member that becomes transparent after formation. From the viewpoints of transparency and seal strength, etc., the average thickness of the heat seal layer is preferably 5 μm or more and 50 μm or less, more preferably 10 μm or more and 30 μm or less.

[0166] (Thermosensitive recording layer forming liquid) The thermosensitive recording layer forming liquid of the present invention contains a compound represented by any one of the above general formulas (1) to (3), a styrene-acrylic resin, and a solvent, preferably contains a leuco dye, and further contains other components as required. As the leuco dye, the compound represented by any one of the above general formulas (1) to (3), the styrene-acrylic resin, and other components, those similar to the above thermosensitive recording layer can be used.

[0167] Examples of the solvent include water, aromatic solvents, ester solvents, ketone solvents, alcohol solvents, aliphatic hydrocarbons, glycol solvents, and petroleum-based solvents containing 1% or less of aromatic components mainly composed of paraffin and naphthene. These may be used alone or in combination of two or more. Examples of the aromatic solvent include benzene, toluene, xylene, etc. Examples of the ester solvent include methyl acetate, ethyl acetate, isopropyl acetate, etc. Examples of the ketone solvent include acetone, methyl ethyl ketone, etc. Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol, n-propyl alcohol, and the like. Examples of the aliphatic hydrocarbon include n-hexane, n-heptane, cyclohexane, and the like. Examples of the glycol solvent include ethylene glycol, diethylene glycol, and the like.

[0168] The heat-sensitive recording layer forming liquid of the present invention, together with a leuco dye, a compound represented by any one of the above general formulas (1) to (3), a styrene-acrylic resin, and the other components, is pulverized and dispersed by a disperser such as a ball mill, an attritor, a sand mill, etc. until the dispersed particle size becomes 0.1 μm or more and 3 μm or less, and then, if necessary, mixed with the other components to be prepared.

[0169] (Method for manufacturing a heat-sensitive recording medium) The method for manufacturing a heat-sensitive recording medium of the present invention includes a heat-sensitive recording layer forming step of forming a heat-sensitive recording layer by applying the heat-sensitive recording layer forming liquid of the present invention on a support, and further includes other steps as necessary.

[0170] The application method is not particularly limited and can be appropriately selected according to the purpose. For example, blade coating method, gravure coating method, gravure offset coating method, bar coating method, roll coating method, knife coating method, air knife coating method, comma coating method, U comma coating method, AKKU coating method, smoothing coating method, microgravure coating method, reverse roll coating method, 4-roll to 5-roll coating method, dip coating method, curtain coating method, slide coating method, die coating method, and the like can be mentioned.

[0171] The adhesion amount after drying of the heat-sensitive recording layer forming liquid is not particularly limited and can be appropriately selected according to the purpose, but 1 g / m 2 or more and 20 g / m 2 or less is preferable, and 2 g / m 2 or more and 10 g / m 2 or less is more preferable.

[0172] There are no particular limitations on the mode of the heat-sensitive recording medium of the present invention, and it can be appropriately selected according to the purpose. For example, it may be used as a label as it is, or a layer for printing information such as characters, marks, pictures, barcodes or two-dimensional codes such as QR codes (registered trademarks) may be provided on the protective layer or the support. Further, it may be in a mode in which an adhesive layer is provided on the side opposite to the side where the heat-sensitive recording layer on the support is provided. Further, the shape of the heat-sensitive recording medium of the present invention is not particularly limited and can be appropriately selected according to the purpose. Examples include label shape, sheet shape, roll shape, and the like.

[0173] <Use> The heat-sensitive recording medium of the present invention can be used in various aspects such as packaging films for various containers such as PET bottles for soft drinks, metal cans for canned coffee, bottles (flasks) for drinks, pharmaceuticals, and beer, and packaging labels in the POS field for fresh foods, boxed lunches, and prepared vegetables.

[0174] Here, embodiments of the heat-sensitive recording medium of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals are given to the same components, and duplicate explanations may be omitted. Further, the number, position, shape, etc. of the following components are not limited to the present embodiment, and can be the preferred number, position, shape, etc. for implementing the present invention.

[0175] <First Embodiment> FIG. 1 is a schematic cross-sectional view showing an example of a heat-sensitive recording medium according to the first embodiment. The heat-sensitive recording medium of this first embodiment has a heat-sensitive recording layer 2 on a support 1.

[0176] <Second Embodiment> FIG. 2 is a schematic cross-sectional view showing an example of a heat-sensitive recording medium according to the second embodiment. The heat-sensitive recording medium of this second embodiment has a heat-sensitive recording layer 2 and a protective layer 3 on a support 1 in this order.

[0177] <Third Embodiment> FIG. 3 is a schematic cross-sectional view showing an example of a thermal recording medium according to the third embodiment. The thermal recording medium of this third embodiment has a printing layer 4 and a thermal recording layer 2 on a support 1 in this order.

[0178] <Fourth Embodiment> FIG. 4 is a schematic cross-sectional view showing an example of a thermal recording medium according to the fourth embodiment. The thermal recording medium of this third embodiment has a printing layer 4, a thermal recording layer 2, and a protective layer 3 on a support 1 in this order.

[0179] <Fifth Embodiment> FIG. 5 is a schematic cross-sectional view showing an example of a thermal recording medium according to the fifth embodiment. The thermal recording medium of this fifth embodiment has a thermal recording layer 2 on a support 1, and has a printing layer 4 on the surface of the support 1 on the side without the thermal recording layer.

[0180] <Sixth Embodiment> FIG. 6 is a schematic cross-sectional view showing an example of a thermal recording medium according to the sixth embodiment. The thermal recording medium of this sixth embodiment has a thermal recording layer 2 and a protective layer 3 on a support 1 in this order, and has a printing layer 4 on the surface of the support 1 on the side without the thermal recording layer.

[0181] <Seventh Embodiment> FIG. 7 is a schematic cross-sectional view showing an example of a thermal recording medium according to the seventh embodiment. The thermal recording medium of this seventh embodiment has a thermal recording layer 2 and a printing layer 4 on a support 1 in this order.

[0182] <Eighth Embodiment> FIG. 8 is a schematic cross-sectional view showing an example of a thermal recording medium according to the eighth embodiment. The thermal recording medium of this eighth embodiment has a thermal recording layer 2, a protective layer 3, and a printing layer 4 on a support 1 in this order.

[0183] (Image Recording Method) The image recording method of the present invention records an image on the thermal recording medium of the present invention using a thermal head. The thermal head is not particularly limited in terms of shape, structure, size, etc., and can be appropriately selected according to the purpose. In this case, considering the storage stability of the thermosensitive recording layer and the matching with the thermal head, it is more preferable to provide a protective layer on the thermosensitive recording layer. However, if a color former system with high image and background storage stability is applied, or if the thermosensitive recording layer itself is imparted with matching properties with the thermal head using fillers, lubricants, etc., it is not always necessary to provide a protective layer. Also, when adding a filler to the protective layer or the thermosensitive recording layer for the purpose of matching with the thermal head, the 50% cumulative volume particle size (D 50 ) measured by a laser diffraction / scattering type particle size distribution measuring device (device name: LA-960, manufactured by Horiba, Ltd.) is too small to achieve matching with the thermal head for the original purpose. Also, if the particle size is too large, the head is likely to wear and it is difficult to impart transparency. Therefore, it is preferably in the range of approximately 0.25 μm to 0.75 μm, but this is not limiting.

[0184] The image recording method of the present invention irradiates the thermosensitive recording medium of the present invention with laser light to record an image. As heating means by laser light, various ones can be considered, but it is preferable to use laser light that can heat non-contact. The laser light is not particularly limited and can be appropriately selected according to the purpose. For example, various generally known laser devices such as gas lasers using gases such as CO2, solid lasers using solids such as YAG and YVO4, semiconductor lasers using III-V group semiconductors or IV-VI group semiconductors can be used, and a device corresponding to the use purpose and usage method can be selected. Among these, in the case of a CO2 laser, since the laser wavelength is 10,000 nm, general materials absorb light, so it is also utilized as a method that can perform thermosensitive recording without adding a special absorption material. In addition, it is necessary to add a photothermal conversion material, which is a material that absorbs laser light with a wavelength of 800 nm to 1100 nm and converts it into heat using semiconductor lasers, YAG of solid-state lasers, or fiber lasers. However, since transparent plastic films such as PET and OPP do not absorb laser light, not only can the laser be directly irradiated onto the thermosensitive recording layer, but also the laser can be irradiated from the transparent film side to record the thermosensitive recording layer provided on the opposite side of the film, thus expanding the applications. The output of the laser light irradiated in the image forming process in the image forming apparatus is not particularly limited and can be appropriately selected according to the purpose. However, 1 W or more is preferable, 3 W or more is more preferable, and 5 W or more is particularly preferable. If it is less than 1 W, it takes time to form an image, and if an attempt is made to shorten the image forming time, the output will be insufficient. Also, the upper limit of the output of the laser light is not particularly limited and can be appropriately selected according to the purpose. However, 200 W or less is preferable, 150 W or less is more preferable, and 100 W or less is particularly preferable. If it exceeds 200 W, it may lead to an increase in the size of the laser device.

[0185] In addition, when performing high-speed image recording on the thermosensitive recording medium, it is preferable to use an image forming apparatus having a laser array in which a plurality of laser light emitting elements are arranged in an array.

[0186] Next, as an example, a laser recording apparatus for recording an image on a long thermosensitive recording medium will be described.

[0187] Here, FIG. 9 is a schematic perspective view of an image recording system 100 which is a laser recording apparatus. In the following description, the conveyance direction (moving direction) of the thermosensitive recording medium will be described as the X-axis direction, the vertical direction as the Z-axis direction, and the direction orthogonal to both the moving direction and the vertical direction as the Y-axis direction. As will be described in detail below, the image recording system 100 irradiates a laser beam onto a thermosensitive recording medium 101 which is an object to be recorded, and performs surface processing or image recording processing. As shown in FIG. 9, the image recording system 100 includes a transport device 10, a recording device 20, a main body unit 30, an optical fiber 42, an encoder unit 60, and the like. The recording device 20 irradiates a laser beam onto a recording target to perform a processing operation on the surface of the recording target or record an image as a visible image on the recording target, and corresponds to a laser irradiation device. The recording device 20 is disposed on the -Y side of the transport device 10, that is, on the -Y side of the transport path. The transport device 10 transports, for example, a thermal recording medium 101 as a recording target using a plurality of rotating rollers. The main body unit 30 is connected to the transport device 10, the recording device 20, and the like, and controls the entire image recording system 100. The encoder unit 60 obtains the moving speed of the thermal recording medium 101.

[0188] FIG. 10 is a schematic perspective view showing the configuration of the image recording system 100. The image recording system 100 includes a laser processing device 30 as a laser light source. The laser processing device 30 includes a laser irradiation device 14 having a laser array unit 14a and a fiber array unit 14b, and an optical unit 43. Here, as the laser irradiation device 14, a fiber array in which laser emission portions of a plurality of optical fibers are arranged in an array in a main scanning direction (Z-axis direction) orthogonal to a sub-scanning direction (X-axis direction) which is the moving direction of a thermal recording medium 101 as a recording target is used to perform surface processing and image recording using a fiber array recording device. The laser processing device 30 irradiates the laser beam emitted from the laser light emitting element 41 onto the thermal recording medium via the fiber array, and records an image (visible image) composed of drawing units. The laser array unit 14a includes a plurality of laser light emitting elements 41 arranged in an array, a cooling unit 50 for cooling the laser light emitting elements 41, a plurality of drive drivers 45 provided corresponding to the laser light emitting elements 41 for driving the corresponding laser light emitting elements 41, and a controller 46 for controlling the plurality of drive drivers 45. Connected to the controller 46 are a power source 48 for supplying power to the laser light emitting elements 41 and an image information output unit 47 such as a personal computer for outputting image information. Normally, in the laser light emitting element 41, energy that is not converted into laser light is converted into heat, causing heat generation. Therefore, the laser light emitting element 41 is cooled by the cooling unit 50, which is a cooling means. Also, in the laser irradiation device 14 here, by using the fiber array unit 14b, it is possible to arrange the laser light emitting elements 41 separately from each other. As a result, it is possible to reduce the influence of heat from adjacent laser light emitting elements 41, and it is possible to efficiently cool the laser light emitting elements 41. Thus, it is possible to avoid temperature rise and variation of the laser light emitting elements 41, reduce the output variation of the laser light, and improve density unevenness. Note that the output of the laser light is the average output measured by a power meter. There are two types of laser light output control methods: a method for controlling the peak power and a method for controlling the light emission ratio of the pulse (duty: laser light emission time / cycle time). The cooling unit 50 is a liquid cooling method in which a coolant is circulated to cool the laser light emitting elements 41, and includes a heat receiving part 51 where the coolant receives heat from each laser light emitting element 41 and a heat radiating part 52 for radiating the heat of the coolant. The heat receiving part 51 and the heat radiating part 52 are connected by cooling pipes 53a and 53b. The heat receiving part 51 is provided with a cooling pipe for the coolant formed of a good heat conductivity member inside a case formed of a good heat conductivity member. The plurality of laser light emitting elements 41 are arranged in an array in the heat receiving part 51. The heat dissipation unit 52 includes a radiator and a pump for circulating the coolant. The coolant sent out by the pump of the heat dissipation unit 52 flows into the heat receiving unit 51 through the cooling pipe 53a. Then, while moving through the cooling pipes in the heat receiving unit 51, the coolant takes away the heat of the laser light emitting elements 41 arranged in the heat receiving unit 51 to cool the laser light emitting elements 41. The coolant that has taken away the heat of the laser light emitting elements 41 and has risen in temperature after flowing out of the heat receiving unit 51 moves through the cooling pipe 53b and flows into the radiator of the heat dissipation unit 52, where it is cooled by the radiator. The coolant cooled by the radiator is sent out to the heat receiving unit 51 again by the pump. The fiber array unit 14b includes a plurality of optical fibers 42 provided corresponding to the laser light emitting elements 41, and an array head 44 that holds the vicinity of the laser emission portions 42a of these optical fibers 42 in an array in the vertical direction (Z-axis direction). The laser incident portion of each optical fiber 42 is attached to the laser emission surface of the corresponding laser light emitting element 41. When trying to hold all the optical fibers 42 with a single array head 44, the array head 44 becomes long and is prone to deformation. As a result, it is difficult to maintain the linearity of the beam array and the uniformity of the beam pitch with a single array head 44. For this reason, the array head 44 is configured to hold 100 to 200 optical fibers 42. Moreover, it is preferable that the laser irradiation device 14 arranges a plurality of array heads 44 that hold 100 to 200 optical fibers 42 in the Z-axis direction, which is a direction orthogonal to the moving direction of the heat-sensitive recording medium 101.

[0189] FIG. 11 is a diagram for explaining the arrangement state of the laser array. As shown in this FIG. 11, the optical fibers 42 of the array head 44 in FIG. 10 are arranged such that the dot diameters R1 formed by irradiating the heat-sensitive recording medium with a laser and coloring are continuous at the focal position focused by the optical unit 43. In the scanning direction of the laser light, there are a main scanning direction and a sub-scanning direction, and the main scanning direction and the sub-scanning direction are orthogonal to each other. The main scanning direction is the direction in which the plurality of optical fibers 42 are arranged. The sub-scanning direction is the direction in which the heat-sensitive recording medium moves. In addition, in order to relatively move the array head 44 and the thermal recording medium to record an image on the thermal recording medium, the array head 44 may move with respect to the thermal recording medium, or the thermal recording medium may move with respect to the array head 44. Even when the array head 44 is moved with respect to the thermal recording medium, if the array head 44 is set as the observation point, the expression of the moving speed of the thermal recording medium can be used.

[0190] Also, as shown in FIG. 10, an optical unit 43 which is an example of an optical system has a collimating lens 43a that converts the diverging laser beam emitted from each optical fiber 42 into a parallel beam, and a condensing lens 43b that condenses the laser beam on the surface of the thermal recording medium which is the laser irradiation surface. Whether or not to provide the optical unit 43 may be appropriately selected according to the purpose.

[0191] An image information output unit 47 such as a personal computer inputs image information to a controller 46. The controller 46 generates a drive signal (control pulse) for driving each drive driver 45 based on the input image information. The controller 46 transmits the generated drive signal (control pulse) to each drive driver 45. Specifically, the controller 46 includes a clock generator. When the number of clocks oscillated by the clock generator reaches a specified number of clocks, the controller 46 transmits a drive signal (control pulse) for driving each drive driver 45 to each drive driver 45. When each drive driver 45 receives a drive signal (control pulse), it transmits a current pulse to drive the corresponding laser light emitting element 41. The laser light emitting element 41 outputs a light emission pulse to irradiate laser light in accordance with the drive of the drive driver 45. The laser light irradiated from the laser light emitting element 41 enters the corresponding optical fiber 42 and is emitted from the laser emission portion 42a of the optical fiber 42. The laser light emitted from the laser emission portion 42a of the optical fiber 42 passes through the collimating lens 43a and the condensing lens 43b of the optical unit 43 and then irradiates the thermal recording medium which is the recording object. When the thermal recording medium is heated by the irradiated laser light, an image is recorded on the thermal recording medium.

[0192] By the way, when a recording device that deflects laser light using a galvano mirror to record an image on a recording object is used, for an image such as characters, the laser light is irradiated and recorded so as to be written in one stroke by the rotation of the galvano mirror. Therefore, when recording a certain amount of information on a recording object, there is a restriction that the recording cannot be completed unless the conveyance of the recording object is stopped. On the other hand, in the laser irradiation device 14, by using a laser array in which a plurality of laser light emitting elements 41 are arranged in an array, an image can be recorded on the thermal recording medium by ON / OFF control of the laser light emitting element corresponding to each pixel. Thereby, even if the amount of information is large, an image can be recorded on the thermal recording medium without stopping the conveyance of the thermal recording medium. Therefore, according to the laser irradiation device 14, even when recording a large amount of information on a recording object, an image can be recorded without reducing productivity.

[0193] The laser irradiation device 14 needs to use a laser light emitting element 41 with a certain level of high output in order to record an image on the heat-sensitive recording medium by irradiating laser light to heat the heat-sensitive recording medium. Therefore, the amount of heat generated by the laser light emitting element 41 is large. In a conventional laser array recording device that does not have the fiber array unit 14b, it is necessary to arrange the laser light emitting elements 41 in an array at intervals corresponding to the resolution. Therefore, in a conventional laser array recording device, in order to achieve a resolution of 200 dpi, the laser light emitting elements 41 need to be arranged at a very narrow pitch. As a result, in a conventional laser array recording device, the heat of the laser light emitting element 41 is difficult to escape, and the laser light emitting element 41 becomes high temperature. In a conventional laser array recording device, when the laser light emitting element 41 becomes high temperature, the wavelength and light output of the laser light emitting element 41 fluctuate, and the recording object cannot be heated to a specified temperature, and a good image cannot be obtained. Also, in a conventional laser array recording device, in order to suppress such a temperature rise of the laser light emitting element 41, it is necessary to reduce the conveyance speed of the recording object and widen the emission interval of the laser light emitting element 41, and the productivity cannot be sufficiently increased.

[0194] Normally, the cooling unit 50 often uses a chiller method, and in this method, only cooling is performed without heating. Therefore, the temperature of the light source does not become higher than the set temperature of the chiller, but the temperature of the cooling unit 50 and the laser light emitting element 41 in contact therewith fluctuates with respect to the environmental temperature. On the other hand, when a semiconductor laser is used as the laser light emitting element 41, a phenomenon occurs in which the laser output changes according to the temperature of the laser light emitting element 41 (the laser output becomes high when the temperature of the laser light emitting element 41 becomes low). Therefore, in order to control the laser output, it is preferable to measure the temperature of the laser light emitting element 41 or the temperature of the cooling unit 50, and control the input signal to the drive driver 45 that controls the laser output so that the laser output becomes constant according to the result, thereby performing normal image formation. In contrast, the laser irradiation device 14 is a fiber array recording device using a fiber array unit 14b. By using a fiber array recording device, the laser emission units 42a of the fiber array unit 14b may be arranged at a pitch according to the resolution, and it is not necessary to set the pitch between the laser light emitting elements 41 of the laser array unit 14a to a pitch according to the image resolution. Thus, according to the laser irradiation device 14, the pitch between the laser light emitting elements 41 can be made sufficiently wide so that the heat of the laser light emitting elements 41 can be sufficiently dissipated. Thereby, according to the laser irradiation device 14, it is possible to suppress the laser light emitting elements 41 from becoming high temperature, and it is possible to suppress fluctuations in the wavelength and light output of the laser light emitting elements 41. As a result, according to the laser irradiation device 14, a good image can be recorded on the heat-sensitive recording medium. Further, even if the emission interval of the laser light emitting elements 41 is shortened, it is possible to suppress the temperature rise of the laser light emitting elements 41, increase the moving speed of the heat-sensitive recording medium, and improve productivity.

[0195] Also, in the laser irradiation device 14, by providing a cooling unit 50 and liquid-cooling the laser light emitting elements 41, it is possible to further suppress the temperature rise of the laser light emitting elements 41. As a result, according to the laser irradiation device 14, furthermore, the emission interval of the laser light emitting elements 41 can be shortened, the moving speed of the heat-sensitive recording medium can be increased, and productivity can be improved. In the laser irradiation device 14, the laser light emitting elements 41 are liquid-cooled, but the laser light emitting elements 41 may be air-cooled using a cooling fan or the like. Liquid cooling has the advantage that the cooling efficiency is higher than air cooling and the laser light emitting elements 41 can be cooled well. On the other hand, by air-cooling, although the cooling efficiency is lower than that of liquid cooling, there is an advantage that the laser light emitting elements 41 can be cooled at low cost.

Embodiment

[0196] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments in any way.

[0197] The compounds of Compound Numbers 1 to 5 used in the following examples were synthesized in the same manner as the synthesis examples described in Patent No. 6751479.

[0198] (Example 1) <Preparation of Thermal Recording Medium> - Preparation of Dye Dispersion - 36 parts by mass of 3 - di - n - butylamino - 6 - methyl - 7 - anilinofluoran, 10 parts by mass of an aqueous solution of a carboxyl group - containing acrylic resin (styrene - acrylic resin, trade name: HPD - 196, solid content 36% by mass, manufactured by BASF), 3.6 parts by mass of a surfactant (trade name: PD - 001, solid content 10% by mass, manufactured by Nisshin Chemical Industry Co., Ltd.), and 50.4 parts by mass of ion - exchanged water were added, and dispersed with a sand mill so that the 50% cumulative volume particle diameter (D 50 ) was 0.2 μm or less to obtain a dye dispersion.

[0199] - Preparation of Color Developer Dispersion - : 36 parts by mass of the compound of Compound Number 1 represented by the following structural formula, 10 parts by mass of an aqueous solution of a carboxyl group - containing acrylic resin (styrene - acrylic resin, trade name: HPD - 196, solid content 36% by mass, manufactured by BASF), 3.6 parts by mass of a surfactant (trade name: PD - 001, solid content 10% by mass, manufactured by Nisshin Chemical Industry Co., Ltd.), and 50.4 parts by mass of ion - exchanged water were added, and dispersed with a sand mill so that the 50% cumulative volume particle diameter (D 50 ) was 0.2 μm to obtain a color developer dispersion.

[0200] <Compound of Compound Number 1>

Chemical Formula

[0201] - Preparation of Thermal Recording Layer Forming Liquid - Next, 12.4 parts by mass of the obtained dye dispersion liquid, 37.3 parts by mass of the color developer dispersion liquid, 21.8 parts by mass of an acrylic emulsion (styrene-acrylic resin, trade name: EK-61, solid content 41% by mass, manufactured by Siden Chemical Co., Ltd.), and 28.5 parts by mass of ion-exchanged water were mixed and stirred to obtain a heat-sensitive recording layer forming liquid.

[0202] -Formation of the heat-sensitive recording layer- Next, on one side of a polyethylene terephthalate film (trade name: E5100, average thickness: 50 μm, manufactured by Toyobo Co., Ltd., haze: 4.5), the heat-sensitive recording layer forming liquid was applied using a bar coater so that the adhesion amount after drying was 4.0 g / m 2 and dried to produce a heat-sensitive recording medium 1. The haze of the polyethylene terephthalate film is a value measured by a haze meter (device name: HZ-V3, manufactured by Suga Test Instruments Co., Ltd.).

[0203] (Example 2) In the preparation of the color developer dispersion liquid of Example 1, a color developer dispersion liquid was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to the compound of Compound No. 2 represented by the following structural formula. Next, in Example 1, a heat-sensitive recording medium 2 was produced in the same manner as in Example 1, except that the color developer dispersion liquid was used for forming the heat-sensitive recording layer.

[0204] <Compound of Compound No. 2>

Chemical formula

[0205] (Example 3) In the preparation of the color developer dispersion liquid of Example 1, a color developer dispersion liquid was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to the compound of Compound No. 3 represented by the following structural formula. Next, in Example 1, a heat-sensitive recording medium 3 was produced in the same manner as in Example 1, except that the color developer dispersion liquid was used for forming the heat-sensitive recording layer.

[0206] Compound No. 3 compound

Chemical formula

[0207] (Example 4) In the preparation of the developer dispersion of Example 1, a developer dispersion was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to the compound of Compound No. 4 represented by the following structural formula. Next, in Example 1, a thermal recording medium 4 was produced in the same manner as in Example 1, except that the developer dispersion was used for forming the thermal recording layer.

[0208] Compound No. 4 compound

Chemical formula

[0209] (Example 5) In the preparation of the developer dispersion of Example 1, a developer dispersion was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to the compound of Compound No. 5 represented by the following structural formula. Next, in Example 1, a thermal recording medium 5 was produced in the same manner as in Example 1, except that the developer dispersion was used for forming the thermal recording layer.

[0210] Compound No. 5 compound

Chemical formula

[0211] (Example 6) In Example 1, on the thermal recording layer, the following coating liquid for the protective layer was applied using a bar coater so that the adhesion amount after drying was 2.0 g / m 2 and a thermal recording medium 6 was produced in the same manner as in Example 1, except that the protective layer was formed.

[0212] <Preparation of the coating liquid for the protective layer> 40.7 parts by mass of calcium carbonate, 11.3 parts by mass of an aqueous solution of a carboxyl group-containing acrylic resin (styrene-acrylic resin, trade name: HPD-196, solid content 36% by mass, manufactured by BASF), 2 parts by mass of a surfactant (trade name: PD-001, solid content 10% by mass, manufactured by Nisshin Chemical Industry Co., Ltd.), and 46 parts by mass of ion-exchanged water were added, and the mixture was dispersed with a sand mill so that the 50% cumulative volume particle size (D 50 ) was 0.2 μm or less as measured by a laser diffraction / scattering particle size distribution measuring device (device name: LA-960, manufactured by Horiba, Ltd.) to obtain a dispersion liquid. Next, 19.9 parts by mass of the obtained dispersion liquid, 21.9 parts by mass of an acrylic emulsion (styrene-acrylic resin, trade name: EK-61, solid content 41% by mass, manufactured by Saiden Chemical Co., Ltd.), 9.2 parts by mass of an oxazoline group-containing polymer emulsion (trade name: WS-500, solid content 39% by mass, manufactured by Nippon Shokubai Co., Ltd.), 4.5 parts by mass of a polyethylene oxide wax dispersion liquid (solid content 30%), and 44.5 parts by mass of ion-exchanged water were mixed and stirred to obtain a coating liquid for the protective layer.

[0213] (Example 7) In the preparation of the dye dispersion liquid of Example 1, a dye dispersion liquid was prepared in the same manner as in Example 1, except that 3-di-n-butylamino-6-methyl-7-anilinofluoran was changed to 6'-(diethylamino)-2'-(2-fluoroanilino)spiro[phthalide-3,9'-xanthene]. Next, in Example 1, a thermal recording medium 7 was produced in the same manner as in Example 1, except that the dye dispersion liquid was used for forming the thermal recording layer.

[0214] (Example 8) In Example 1, a thermal recording medium 8 was produced in the same manner as in Example 1, except that the following thermal recording layer forming liquid was used to form the thermal recording layer.

[0215] <Thermal recording layer forming liquid> 6.7 parts by mass of the dye dispersion prepared in Example 1, 20 parts by mass of the developer dispersion prepared in Example 1, 5.9 parts by mass of an acrylic emulsion (styrene-acrylic resin, trade name: EK-61, solid content 41% by mass, manufactured by Siden Chemical Co., Ltd.), 24.1 parts by mass of an aqueous solution of itaconic acid-modified polyvinyl alcohol (trade name: Kuraray Poval 25-88KL, solid content 10% by mass, manufactured by Kuraray Co., Ltd.), and 43.4 parts by mass of ion-exchanged water were mixed and stirred to prepare a heat-sensitive recording layer forming solution.

[0216] (Example 9) In Example 1, a heat-sensitive recording medium 9 was produced in the same manner as in Example 1, except that a heat-sensitive recording layer was formed using the following heat-sensitive recording layer forming solution. <Heat-sensitive recording layer forming solution> 12 parts by mass of the dye dispersion prepared in Example 1, 36.2 parts by mass of the developer dispersion prepared in Example 1, 21.2 parts by mass of an acrylic emulsion (styrene-acrylic resin, trade name: EK-61, solid content 41% by mass, manufactured by Siden Chemical Co., Ltd.), 3 parts by mass of a cesium tungsten oxide dispersion (trade name: YMW-D20, solid content 28.5% by mass, manufactured by Sumitomo Metal Mining Co., Ltd.) as a photothermal conversion material, and 27.6 parts by mass of ion-exchanged water were mixed and stirred to prepare a heat-sensitive recording layer forming solution.

[0217] (Example 10) In Example 1, on the surface of the support, printing ink (trade name: Finart R794 white G8, solid content 42% by mass, manufactured by DIC Graphics Co., Ltd.) was applied using a bar coater so that the adhesion amount after drying was 1.0 g / m 2 and a heat-sensitive recording medium 10 was produced in the same manner as in Example 1, except that a printing layer was formed.

[0218] (Comparative Example 1) In the preparation of the developer dispersion in Example 1, the developer dispersion was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to N-[2-[[(phenylamino)carbonyl]amino]phenyl]benzenesulfonamide (trade name: NKK-1304, manufactured by Nippon Soda Co., Ltd.). Next, in Example 1, a thermal recording medium 11 was produced in the same manner as in Example 1, except that the color developer dispersion was used for forming the thermal recording layer.

[0219] (Comparative Example 2) In the preparation of the color developer dispersion of Example 1, the color developer dispersion was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to 4-methyl-N-[[[3-[[(4-methylphenyl)sulfonyl]oxy]phenyl]amino]carbonyl]benzenesulfonamide (trade name: P-201, manufactured by BASF). Next, in Example 1, a thermal recording medium 12 was produced in the same manner as in Example 1, except that the color developer dispersion was used for forming the thermal recording layer.

[0220] (Comparative Example 3) In the preparation of the color developer dispersion of Example 1, the color developer dispersion was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to 4-hydroxy-4'-isopropoxydiphenyl sulfone (trade name: D-8, manufactured by Nippon Soda Co., Ltd.). Next, in Example 1, a thermal recording medium 13 was produced in the same manner as in Example 1, except that the color developer dispersion was used for forming the thermal recording layer.

[0221] (Comparative Example 4) In the preparation of the color developer dispersion of Example 1, the color developer dispersion was prepared in the same manner as in Example 1, except that the compound of Compound No. 1 was changed to bis(4-hydroxyphenyl)sulfone monoallyl ether (trade name: BPS-MAE, manufactured by Nikka Chemical Co., Ltd.). Next, in Example 1, a thermal recording medium 14 was produced in the same manner as in Example 1, except that the color developer dispersion was used for forming the thermal recording layer.

[0222] (Comparative Example 5) In the preparation of the dye dispersion and the developer dispersion of Example 1, 10 parts by mass of an aqueous carboxyl group-containing acrylic resin solution (styrene-acrylic resin, trade name: HPD-196, solid content 36% by mass, manufactured by BASF) was changed to 18 parts by mass of an aqueous polyvinyl alcohol solution (trade name: Gosenex L-3266, solid content 30% by mass, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), and 50.4 parts by mass of ion-exchanged water was changed to 42.3 parts by mass. A dye dispersion and a developer dispersion were prepared in the same manner as in Example 1 except for this change. Next, 8.7 parts by mass of the obtained dye dispersion, 25.9 parts by mass of the developer dispersion, 31.2 parts by mass of an aqueous itaconic acid-modified polyvinyl alcohol solution (trade name: Kuraray Poval 25-88KL, solid content 10% by mass, manufactured by Kuraray Co., Ltd.), 5 parts by mass of an aqueous polyamide epichlorohydrin resin solution (trade name: WS-525, solid content 25% by mass, manufactured by Starlight PMC Co., Ltd.), and 29.3 parts by mass of ion-exchanged water were mixed and stirred to prepare a heat-sensitive recording layer forming solution. Next, in Example 1, a heat-sensitive recording medium 15 was produced in the same manner as in Example 1 except that the above heat-sensitive recording layer forming solution was used to form a heat-sensitive recording layer.

[0223] (Comparative Example 6) In the preparation of the dye dispersion and the developer dispersion of Example 1, 10 parts by mass of an aqueous carboxyl group-containing acrylic resin solution (styrene-acrylic resin, trade name: HPD-196, solid content 36% by mass, manufactured by BASF) was changed to 7.2 parts by mass of an aqueous polyurethane resin solution (trade name: Gen 0851, solid content 50% by mass, manufactured by Borchers), and 50.4 parts by mass of ion-exchanged water was changed to 53.2 parts by mass. A dye dispersion and a developer dispersion were prepared in the same manner as in Example 1 except for this change. Next, 14.7 parts by mass of the obtained dye dispersion, 44.1 parts by mass of the developer dispersion, 15.1 parts by mass of a polyurethane resin dispersion (trade name: WLS-201, solid content 35% by mass, manufactured by DIC Corporation), and 26 parts by mass of ion-exchanged water were mixed and stirred to prepare a heat-sensitive recording layer forming solution. Next, in Example 1, a heat-sensitive recording medium 16 was produced in the same manner as in Example 1 except that the above heat-sensitive recording layer forming solution was used to form a heat-sensitive recording layer.

[0224] Next, using the thermosensitive recording media of Examples 1 to 10 and Comparative Examples 1 to 6 prepared, the following were evaluated: "hot water resistance (60°C)", "hot water resistance (40°C)", "water resistance", "ethanol resistance", "temperature and humidity resistance", "water rubbing resistance", "heat resistance (110°C)", "heat resistance (90°C)", and "printability with LD laser". The results of "hot water resistance (60°C)", "hot water resistance (40°C)", "water resistance", "ethanol resistance", "temperature and humidity resistance", "water rubbing resistance", "heat resistance (110°C)", and "heat resistance (90°C)" are shown in Table 1 and Table 2.

[0225] <Hot water resistance (60°C)> For each thermosensitive recording medium, a pre-test image sample was prepared by printing using a CO2 laser marker (device name: LP-435TU, manufactured by SUNX Ltd.) under the following printing conditions. The prepared pre-test image sample was immersed in tap water at 60°C, and the image density before and after storage for 96 hours while maintaining the water temperature at 60°C using a constant temperature bath was measured with a reflection densitometer (X-Rite eXact, manufactured by X-Rite). The image residual rate was determined from the following formula and evaluated according to the following criteria. Image residual rate (%) = [(image density after the test) / (image density before the test)] × 100 [Printing conditions] · Work distance: 275 mm · Scanning speed: 900 mm / s · Laser light wavelength: 10.6 μm · Laser power: 10% [Evaluation criteria] ◎: Image residual rate is 90% or more ○: Image residual rate is 80% or more and 89% or less ×: Image residual rate is 79% or less

[0226] <Hot water resistance (40°C)> Each prepared pre-test image sample was immersed in tap water at 40°C, and the image density before and after storage for 96 hours while maintaining the water temperature at 40°C using a constant temperature bath was measured with a reflection densitometer (X-Rite eXact, manufactured by X-Rite). The image residual rate was determined from the following formula and evaluated according to the following criteria. Image residual rate (%) = [(Image density after test) / (Image density before test)] × 100 [Evaluation criteria] ◎: Image residual rate is 90% or more ○: Image residual rate is 80% or more and 89% or less ×: Image residual rate is 79% or less

[0227] <Water resistance> The image densities of each prepared image sample before and after being immersed in tap water at 23°C for 96 hours were measured with a reflection densitometer (X-Rite eXact, manufactured by X-Rite), and the image residual rate was determined from the following formula and evaluated according to the following criteria. Image residual rate (%) = [(Image density after test) / (Image density before test)] × 100 [Evaluation criteria] ◎: Image residual rate is 90% or more ○: Image residual rate is 80% or more and 89% or less ×: Image residual rate is 79% or less

[0228] <Ethanol resistance> The image densities of each prepared image sample before and after being immersed in an 80% by mass ethanol aqueous solution for 30 seconds were measured with a reflection densitometer (X-Rite eXact, manufactured by X-Rite), and the image residual rate was determined from the following formula and evaluated according to the following criteria. Image residual rate (%) = [(Image density after test) / (Image density before test)] × 100 [Evaluation criteria] ◎: Image residual rate is 90% or more ○: Image residual rate is 80% or more and 89% or less ×: Image residual rate is 79% or less

[0229] <Temperature and humidity resistance> The image densities of each prepared image sample before and after being stored in an environment of 40°C and 90% RH for 72 hours were measured with a reflection densitometer (X-Rite eXact, manufactured by X-Rite), and the image residual rate was determined from the following formula and evaluated according to the following criteria. Image residual rate (%) = [(Image density after test) / (Image density before test)] × 100 [Evaluation criteria] ◎: Image residual rate is 90% or more ○: Image residual rate is 80% or more and 89% or less ×: Image residual rate is 79% or less

[0230] <Water resistance rubbing fastness> One drop of water was dropped onto each prepared image sample and strongly rubbed 100 times with a finger, and then the presence or absence of peeling, dissolution, and bleeding of each layer was visually observed and evaluated according to the following criteria. [Evaluation criteria] ○: No peeling, elution, or bleeding ×: Peeling, elution, or bleeding present

[0231] <Heat resistance> After storing each prepared image sample under environmental conditions of 110 °C and 90 °C for 1 hour, the density of the sample base fabric part was measured with a reflection densitometer (X-Rite eXact, manufactured by X-Rite), and evaluated according to the following criteria. [Evaluation criteria] ○: Density of the base fabric part is 0.29 or less ×: Density of the base fabric part is 0.30 or more

[0232] <Feasibility of LD laser printing> Using an LD laser marker (device name: Ricoh Rewritable Laser Marker LDM200, manufactured by Ricoh Company, Ltd.), heat-sensitive recording media prepared in Examples 1 to 10 and Comparative Examples 1 to 6 were printed under the following printing conditions to prepare image samples, and evaluated based on the following evaluation criteria. [Printing conditions] Work distance: 150 mm Scanning speed: 3,000 mm / s Laser light wavelength: 980 nm Laser power: 70% [Evaluation criteria] ○: Printable ×: Unprintable

[0233] [Evaluation results] Example 9, which contains a photothermal conversion material in the heat-sensitive recording layer, was printable (〇), while Examples 1 to 8, 10 and Comparative Examples 1 to 6, which do not contain a photothermal conversion material in the heat-sensitive recording layer, were non-printable (×).

[0234]

Table 1

[0235]

Table 2

[0236] As an aspect of the present invention, for example, it is as follows. <1> A heat-sensitive recording medium having a support and a heat-sensitive recording layer on the support, wherein the heat-sensitive recording layer contains a compound represented by the following general formula (1) and a styrene-acrylic resin.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0237] According to the heat-sensitive recording medium according to any one of <1> to <8> above, the heat-sensitive recording layer forming liquid according to any one of <9> to <11> above, the method for manufacturing a heat-sensitive recording medium according to <12> above, and the image recording method according to any one of <13> to <14> above, various problems in the prior art can be solved and the object of the present invention can be achieved.

Explanation of reference numerals

[0238] 1 Support 2 Heat-sensitive recording layer 3 Protective layer 4 Printing layer

Prior art documents

Patent documents

[0239]

Patent Document 1

Claims

1. A thermal recording medium having a support and a thermal recording layer on the support, characterized in that the thermal recording layer contains a compound represented by the following general formula (1) and a styrene-acrylic resin. 【Chemical 1】 However, in the general formula (1), R ２ is a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms, an unsubstituted or 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 an aralkyl group having 7 to 12 carbon atoms substituted with a halogen atom, an unsubstituted or 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 an aryl group having 6 to 12 carbon atoms substituted with a halogen atom, and a plurality of R ２ may be the same or different. A １ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A plurality of A １ may be the same or different.

2. The thermal recording medium according to Claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2). 【Chemical 2】 However, in the general formula (2), R ２ is a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms, an unsubstituted or 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 an aralkyl group having 7 to 12 carbon atoms substituted with a halogen atom, an unsubstituted or 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 an aryl group having 6 to 12 carbon atoms substituted with a halogen atom, and a plurality of R ２ may be the same or different.

3. The thermal recording medium according to Claim 2, wherein the compound represented by the general formula (2) is a compound represented by the following general formula (3). [Chemical Formula 3] However, in the general formula (3), R represents an alkyl group and n represents an integer of 0 to 3.

4. The thermal recording medium according to any one of Claims 1 to 3, wherein the thermal recording layer contains a photothermal conversion material.

5. The thermal recording medium according to any one of Claims 1 to 4, wherein the support is a plastic film.

6. The thermal recording medium according to any one of Claims 1 to 5, wherein the support is a transparent film.

7. The thermal recording medium according to any one of Claims 1 to 6, having a protective layer on the thermal recording layer.

8. The thermal recording medium according to any one of Claims 1 to 6, having a printing layer on any one of the support and the surface of the support opposite to the thermal recording layer and on the thermal recording layer.

9. A thermal recording layer forming liquid containing a compound represented by the following general formula (1), a styrene-acrylic resin, and a solvent. 【Chemical Formula 4】 However, in the general formula (1), R ２ is a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms, an unsubstituted or 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 an aralkyl group having 7 to 12 carbon atoms substituted with a halogen atom, an unsubstituted or 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 an aryl group having 6 to 12 carbon atoms substituted with a halogen atom, and a plurality of R ２ may be the same or different. A １ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A plurality of A １ may be the same or different.

10. The thermal recording layer forming liquid according to Claim 9, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2). 【Chemical Formula 5】 However, in the general formula (2), R ２ is a linear, branched or alicyclic alkyl group having 1 to 12 carbon atoms, an unsubstituted or 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 an aralkyl group having 7 to 12 carbon atoms substituted with a halogen atom, an unsubstituted or 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 an aryl group having 6 to 12 carbon atoms substituted with a halogen atom, and a plurality of R ２ may be the same or different.

11. The thermal recording layer forming liquid according to Claim 10, wherein the compound represented by the general formula (2) is a compound represented by the following general formula (3). 【Chemical Formula 6】 However, in the general formula (3), R represents an alkyl group and n represents an integer of 0 to 3.

12. A method for manufacturing a thermal recording medium, comprising a thermal recording layer forming step of applying the thermal recording layer forming liquid according to any one of Claims 9 to 11 on a support to form a thermal recording layer.

13. An image recording method, characterized in that a laser beam is irradiated on the thermal recording medium according to any one of Claims 1 to 8 to record an image.

14. An image recording method, characterized in that an image is recorded on the thermal recording medium according to any one of Claims 1 to 8 using a thermal head.

Images