JP2019084758A - Thermal recording material - Google Patents

Abstract

To provide a thermal recording material which has good color developing sensitivity and excellent heat resistance of a printed part.SOLUTION: A thermal recording material contains a developer and a colorless or pale leuco dye on a substrate, and is characterized by containing compounds in the figure and 1,3-diphenylurea.SELECTED DRAWING: None

Description

  The present invention relates to a heat-sensitive recording material having a good color developing sensitivity and a heat resistant background.

  In general, the heat-sensitive recording material is prepared by dispersing the leuco dye and the developer such as the phenolic compound separately in the form of fine particles and then mixing the two, and adding the binder, the sensitizer, the filler, the lubricant, etc. A coating liquid obtained by adding an additive is applied to paper, film, synthetic paper, etc., and a color reaction is caused by the chemical reaction that occurs when one or both of the leuco dye and the developer is melted and heated. It is the one to get a record. In order to color (print) such a thermosensitive recording material, a thermal printer or the like incorporating a thermal head is used. Compared to other recording methods, this thermal recording method is (1) no noise during recording, (2) no need for development and fixing, (3) maintenance free, (4) machines are relatively It is widely used in the field of facsimile, the output of computers, the field of printers such as calculators, the field of recorders for medical measurement, the field of automatic ticket vending machines, the field of heat sensitive recording labels, etc.

  In recent years, while the use application of the heat-sensitive recording material is expanded, the demand for high-speed recording is further increased to improve productivity, and development of a heat-sensitive recording material capable of sufficiently coping with high-speed recording is strongly desired. In this case, a developer having a low melting point and a small heat of fusion is required, but this property causes deterioration of the unrecorded (uncolored) part (background) of the thermosensitive recording material during manufacture, use or storage Not only high whiteness but also improvement of stability is strongly desired.

  In general, a developer having a phenolic hydroxyl group has a high color developing ability, and a bisphenol-based developer is, among others, 2,2-bis (4-hydroxyphenylpropane) shown in Patent Document 1, for example, from the height of coloring density. A number of reports have been made, including (bisphenol A) and 4,4′-dihydroxydiphenyl sulfone (bisphenol S) shown in Patent Document 2. However, these have disadvantages, such as deterioration of the ground surface (surface covering).

U.S. Pat. No. 3,539,375 JP-A-57-11088

  An object of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a thermosensitive recording material having a high color forming sensitivity and a high printing stability on a printed part.

  As a result of intensive studies to achieve the above object, the present inventor has found that a compound represented by the following general formula (1) and the general formula (2) and a mixture of 1,3-diphenylurea as a color developer. When used in a heat-sensitive recording material, the inventors have newly found that the color development sensitivity is excellent and the printed portion is excellent in heat resistance, and the present invention has been completed.

［式（１）及び式（２）中、Ａはヘテロ原子を含んでいても良い炭素数１０以下の２価の飽和炭化水素基である。］
（２）前記一般式（１）で表される化合物が下記式（３）であり、前記一般式（２）で表される化合物が下記式（４）である（１）に記載の感熱記録材料、

（３）一般式（１）及び一般式（２）で表される化合物並びに１，３−ジフェニル尿素の混合比が、１０〜９０：５〜５０：５〜８０である（１）又は（２）に記載の感熱記録材料、
（４）（１）乃至（３）のいずれか一つに記載の感熱記録材料を含む感熱記録層、
（５）（１）乃至（４）のいずれか一つに記載の感熱記録材料又は感熱記録層を含む感熱記録紙、
に関する。 That is, the present invention
(1) A thermosensitive recording material comprising a compound represented by the following general formula (1) or (2) and 1,3-diphenylurea,

[In Formula (1) and Formula (2), A is a C 10 or less bivalent saturated hydrocarbon group which may contain a hetero atom. ]
(2) The heat-sensitive recording according to (1), wherein the compound represented by the general formula (1) is the following formula (3) and the compound represented by the general formula (2) is the following formula (4) material,

(3) The mixing ratio of the compound represented by the general formula (1) and the general formula (2) and 1,3-diphenylurea is 10 to 90: 5 to 50: 5 to 80. (1) or (2) The thermosensitive recording material as described in
(4) A thermosensitive recording layer comprising the thermosensitive recording material according to any one of (1) to (3),
(5) A thermosensitive recording paper comprising the thermosensitive recording material or thermosensitive recording layer according to any one of (1) to (4),
About.

  The present invention uses the compounds represented by the above general formula (1) and the general formula (2) and 1,3-diphenylurea (hereinafter abbreviated as compound (5)) as a color developer to obtain color development sensitivity. Can be realized, and a thermosensitive recording material in which the printed portion exhibits high stability to heat can be realized.

The invention will be described in detail.
The present invention is a heat-sensitive recording material provided with a heat-sensitive recording layer containing a leuco dye of colorless to light color and a color developer on a support, which comprises the above general formula (1) and the general formula (2) as a color developer. The compound (5) is contained together with the compound represented by 1.), and, if necessary, other developers, sensitizers, preservative improvers, binders, fillers and other additives shown below. The present invention relates to a thermosensitive recording material containing

A in the above general formula (1) and general formula (2) is a linear or branched C _{1 to} C ₁₀ saturated carbonization which may contain a hetero atom such as an oxygen atom, a nitrogen atom, a sulfur atom or a phosphorus atom It is a hydrogen group.

A as a linear saturated hydrocarbon group is a non-substituted C _{1 to} C ₁₀ alkylene group, among which a C _{1 to} C ₈ alkylene group is preferable, and a C _{1 to} C ₄ alkylene group is particularly preferable. A methylene group, ethylene group, n-propylene group, n-butylene group etc. are mentioned as the specific example.

A as a branched saturated hydrocarbon group is a C _{1 to} C ₁₀ alkylene group having a substituent, and examples of the substituent include a C _{1 to} C ₈ alkyl group and the like, and as a specific example thereof, A methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group etc. are mentioned.

Examples of A as a saturated hydrocarbon group containing a hetero atom include a linking group represented by General Formula (6). ^{A 1} and ^{A 2} in the general formula (6) each represent a C ₁ -C ₉ alkylene group, the total number of carbon atoms of ^{A 1} and ^{A 2} is 10 or less. Further, X represents a hetero atom such as an oxygen atom, a nitrogen atom, a sulfur atom or a phosphorus atom, and is preferably an oxygen atom or a nitrogen atom.

  Although the specific example of a compound represented by General formula (1) used for this invention is given to the following table 1, it is not limited to these.

  Specific examples of the compound represented by the general formula (2) used in the present invention are listed in the following Table 2, but are not limited thereto.

The mixing ratio of each of the compounds represented by the general formula (1) and the general formula (2) and the compound (5) used in the heat-sensitive recording material of the present invention is 10 to 90 in the general formula (1). (2) is preferably 5 to 50, and the compound (5) is preferably 5 to 80, and the formula (1) is preferably 10 to 70, the formula (2) may be 10 to 40, and the compound (5) may be 10 to 60. The mixture of these three compounds is analyzed by high performance liquid chromatography (hereinafter abbreviated as HPLC), and the ratio of area% of each compound obtained according to the following formula (I) is referred to as “mixing ratio”. did. The area% of each compound is obtained by adding the area% of the compound represented by the above general formula (1) and the general formula (2) and the area% of the compound (5) to 100 and showing the area% of each compound as a percentage It is.
Mixing ratio = [(area percentage of compound represented by general formula (1)): (area percentage of compound represented by general formula (2)): (area percentage of compound (5))] (I)

  Next, the compounds represented by the above general formula (1) and the general formula (2) and the compound (5) used in the present invention can be easily produced as a mixture of reaction products from the following reaction steps.

As a method for producing the compound, for example, phenyl isocyanate (hereinafter abbreviated as compound (1-1)), 1-aminopropan-2-ol (hereinafter abbreviated as compound (1-2)) and aniline (hereinafter abbreviated) The compound represented by Compound No. 5 in Table 1 (hereinafter abbreviated as Compound (3)) by reacting Compound (1-3) at a predetermined mixing ratio, Table 2 It can be easily produced as a mixture of a compound represented by Compound No. 5 (hereinafter abbreviated as Compound (4)) and Compound (5).

  In addition, the compound (1-1) and the compound (1- (1)) which are used to synthesize a mixture of the general formula (1), the general formula (2) and the compound (5) suitably used in the present invention 2) and the amount of the compound (1-3) used are usually 1.1 to 3 moles of the compound (1-1) and 1.5 to 2 moles per 1 mole of the compound (1-2). The molar ratio is preferable, and the amount of the compound (1-3) is usually 0.001 to 0.5, and preferably 0.02 to 0.4.

  In the above-mentioned production process, a base can be used to accelerate the reaction if necessary, and specific examples of the base used include organic bases such as triethylamine and pyridine; sodium hydroxide, potassium hydroxide, sodium carbonate, Inorganic bases such as potassium carbonate and the like can be mentioned.

  The reaction temperature in the above steps is preferably 0 ° C. to 100 ° C., with little by-product formation, and the reaction can be smoothly carried out.

  The solvent used in the above production process is not particularly limited as long as it does not affect the reaction. For example, amide compounds such as N, N-dimethylformamide, N, N-dimethylacetamide, and N-methylpyrrolidone; halogenated hydrocarbon compounds such as methylene chloride, chloroform, dichloroethane; and aromatics such as benzene, toluene, and xylene Hydrocarbon compounds; Ether compounds such as dioxane, tetrahydrofuran, anisole, ethylene glycol dimethyl ether, dimethylene glycol dimethyl ether, and diethylene glycol diethyl ether; Sulfone compounds such as sulfolane; Sulfoxide compounds such as dimethyl sulfoxide; You may use it.

  In preparing the heat-sensitive recording material of the present invention, the coloring compound is usually 1 to 50% by mass, preferably 5 to 30% by mass, and the compounds and compounds represented by the above general formula (1) and general formula (2) The mixture of 5) is usually 1 to 70% by mass, preferably 10 to 50% by mass, the sensitizer is usually 1 to 80% by mass, the preservative improving agent is usually 0 to 30% by mass, and the binder is usually 1 to 90% by weight, filler is usually 0 to 80% by weight, other lubricants, surfactants, antifoaming agents, UV absorbers are used in arbitrary proportions, for example, each usually 0 to 30% by weight (% by weight Is the mass ratio of each component in the thermosensitive recording material). In the heat-sensitive recording material of the present invention, a developer, a sensitizer or other additives known per se other than the above components may be used in combination.

  The color forming compound used in the present invention is not particularly limited as long as it is generally used for pressure-sensitive recording paper and thermosensitive recording paper, and, for example, fluoran compounds, triarylmethane compounds, spiro compounds And diphenylmethane compounds, thiazine compounds, lactam compounds, and fluorene compounds, with fluoran compounds being preferred.

  Specific examples of the fluoran compound include 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) Amino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isobutylamino) ) -6-Methyl-7-anilinofluorane, 3- [N-ethyl-N- (3-ethoxypropyl) amino] -6-methyl-7-anilinofluorane, 3- (N-ethyl-N, -Hexylamino) -6-methyl-7-anilinofluorane, 3-dipentylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-propylamino) -6-methyl- -Anilinofluorane, 3- (N-ethyl-N-tetrahydrofurylamino) -6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (p-chloroanilino) fluorane, 3- Diethylamino-6-methyl-7- (p-fluoroanilino) fluoran, 3- [N-ethyl-N- (p-tolyl) amino] -6-methyl-7-anilinofluorane, 3-diethylamino-6 -Methyl-7- (p-toluidino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino) fluoran, 3-diethylamino-7- (o-fluoro ani) Lino) fluorane, 3-dibutylamino-7- (o-fluoroanilino) fluorane, 3-diethylamino-7- (3 ,, -Dichloroanilino) fluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilino Fluoran, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluoran, 3-diethylamino-7-octylfluoran, 3- [N-ethyl-N- (p-tolyl) amino]- 6-methyl-7-phenethylfluoran etc. is mentioned, 3-dibutylamino-6-methyl-7-anilinofluorane is preferable.

  Specific examples of the triarylmethane compounds include: 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (alias: crystal violet lactone or CVL), 3,3-bis (p-dimethylamino) Phenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,2-dimethylaminoindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-methylindole-3) -Yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindol-3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethyl Aminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis (9- Thilcarbazol-3-yl) -5-dimethylaminophthalide, 3,3- (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- (1-- Methylpyrrol-2-yl) -6-dimethylaminophthalide and the like can be mentioned.

  Specific examples of spiro compounds include 3-methyl spirodinaphthopyran, 3-ethyl spiro dinaphthopyran, 3,3'-dichloro spiro dinaphthopyran, 3-benzyl spiro dinaphthopyran, 3-propyl spiro benzopyran 3-methylnaphtho- (3-methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro (indoline-2,2'-benzopyran), etc .; specific examples of diphenylmethane compounds For example, N-halophenyl-leucoauramine, 4,4-bis-dimethylaminophenylbenzhydryl benzyl ether, N-2,4,5-trichlorophenyl leucoauramine etc .; As specific examples of a thiazine compound, for example, Benzoyl leuco methylene blue, p-nitro benzoyl leuco methylene Specific examples of lactam compounds include, for example, Rhodamine B anilinolactam, Rhodamine B-p-chloroanilinolactam, and the like; and specific examples of fluorene compounds, for example, 3,6-bis (dimethylamino) fluorene Spiro (9,3 ′)-6′-dimethylaminophthalide, 3,6-bis (dimethylamino) fluorenespiro (9,3 ′)-6′-pyrrolidinophthalide, 3-dimethylamino-6-diethylamino Fluorene spiro (9,3 ')-6'- pyrrolidinophthalide etc. are mentioned. These chromogenic compounds are used alone or in combination.

  The color developer used in the present invention is not particularly limited as long as it is generally used for pressure-sensitive recording paper and thermosensitive recording paper, and examples thereof include α-naphthol, β-naphthol, p-octylphenol, 4 -T-octylphenol, p-t-butylphenol, p-phenylphenol, 1,1-bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) propane (alias: bisphenol A or BPA), 2,2-bis (p-hydroxyphenyl) butane, 1,1-bis (p-hydroxyphenyl) cyclohexane, 4,4′-thiobisphenol, 4,4′-cyclohexylidenediphenol, 2,2 ′ -Bis (2,5-dibromo-4-hydroxyphenyl) propane, 4,4'-isopropylidene bis (2-t) -Butylphenol), 2,2'-methylenebis (4-chlorophenol), 4,4'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methoxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4-hydroxy- 4'-Isopropoxydiphenyl sulfone, 4-hydroxy-4'-ethoxydiphenyl sulfone, 4-hydroxy-4'-butoxydiphenyl sulfone, 4-hydroxy-4'-benzyloxydiphenyl sulfone, bis (4-hydroxyphenyl) acetic acid Phenolic compounds such as methyl, bis (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, 2,4-dihydroxy-2'-methoxybenzanilide, benzyl p-hydroxybenzoate, p-hydroxy Cheap Aroma such as ethyl benzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, 3,5-di-α-methylbenzylsalicylic acid Group carboxylic acid derivative, aromatic carboxylic acid or polyvalent metal salt thereof, benzotriazole, 5-methyl-1H-benzotriazole, 4-methyl-1H-benzotriazole, phenyl-6 benzotriazole, phenyl-5 benzotriazole, chloro Benzotriazole derivatives such as 5-benzotriazole, chloro-5 methylbenzotriazole, chloro-5 isopropyl-7 methyl-4 benzotriazole, bromo-5 benzotriazole, saccharin, 1-bromosaccharin, 1-nitrosaccharin, 1-amino saccharin Etc., methanylanilide, N-phenyl-4-aminobenzenesulfonamide, neourilone, N-phenyl-3-nitrobenzenesulfonamide, N- (4-methyl-2-nitrophenyl) benzenesulfonamide, N- (2 Sulfonamide derivatives such as -methoxyphenyl) -p-toluenesulfonamide, N- (2- (3-phenylureido) phenyl) benzenesulfonamide, N- (p-toluenesulfonyl) -N '-(3-n- Butylaminosulfonylphenyl) urea, N- (p-toluenesulfonyl) -N '-(4-trimethylacetophenyl) urea, N- (benzenesulfonyl) -N'-(3-p-toluenesulfonyloxyphenyl) urea, N- (p-toluenesulfonyl) -N '-(3-p-toluenes Honirufeniru) urea, N-(p-toluenesulfonyl) -N '- (3- phenylsulfonyloxy phenyl) urea, tolbutamide, etc. sulfonylurea derivatives such as chlorpropamide and the like.

  Specific examples of the sensitizer (heat fusible compound) according to the present invention include, for example, wax, carnauba wax, shellac, paraffin, montan wax, oxidized paraffin, polyethylene wax, amide wax, oxidized polyethylene, stearic acid, Behenic acid, stearic acid amide, oleic acid amide, N-methyl stearic acid amide, erucic acid amide, methylol behenic acid amide, methylol stearic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, stearic acid anilide, linoleic acid Anilide, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, 1,4-diethoxynaphthalene, 2,6-diisopropylnaphthalene, 1,2-diphenoxyethane, 1, -Diphenoxybutane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1,2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy- 2- (4-chlorophenoxy) ethane, 1-phenoxy-2- (4-methoxyphenoxy) ethane, 1,2-diphenoxymethylbenzene, o-xylylene bis (phenyl ether), diphenyl glycol, benzyl p-hydroxybenzoate Ester, p-benzyloxybenzoic acid benzyl ester, terephthalic acid dibenzyl ester, dimethyl phthalate, isophthalic acid dibenzyl, p-toluenesulfonic acid phenyl ester, phenyl mesitylene sulfonate, 4-methylphenyl mesitylene sulfonate, 4-tolymesitylene Sulfona Diphenyl carbonate, oxalic acid dibenzyl ester, oxalic acid di (4-chlorobenzyl) ester, oxalic acid di (4-methylbenzyl) ester, p-benzylbiphenyl, 4-methoxybiphenyl, 4-methylphenylbiphenyl ether, p-Allyloxybiphenyl, 4- (m-methylphenoxymethyl) biphenyl, m-terphenyl, p-toluenesulfonamide, benzenesulfonanilide, p-toluenesulfonanilide, 4,4'-diallyloxydiphenylsulfone, diphenyl sulfone 4,4'-Dimethyl benzophenone, dibenzoylmethane, p-acetotoluidine, secylbiphenyl compound, 1,4-diacetoxybenzene, 1,4-dipropionoxybenzene, 2-phenoxyethyl-N-phenylcarbamete And 1,4-diglycidyl oxybenzene, 4,4′-diglycidyl oxydiphenyl sulfone, 4-benzyloxy-4 ′-(2-methylglycidyloxy) diphenyl sulfone, 2,2′-methylene bis (4, 6-di-t-butylphenyl) phosphate, metal salt of 2,2′-methylenebis (4,6-di-t-butylphenyl) phosphate, ammonium salt and polyvalent metal salt, metal salt of p-nitrobenzoic acid, Metal salts of phthalic acid monobenzyl ester, metal salts of cinnamic acid, p-hydroxyacetanilide, p-hydroxybutyranide, p-hydroxynonalinide, 2,2'-methylenebis (4-methyl-6-t-butylphenol) ), 4,4′-Butylidene-bis (3-methyl-6-t-butylphenol), 4,4′-thiobis (2-t) Butyl-5-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, bis (3-t-butyl-4-hydroxy-6-methylphenyl) Sulfone, bis (3,5-dibromo-4-hydroxyphenyl) sulfone, 4,4′-sulfonylbis (2-t-butyl-5-methylphenol), 4- [α- (hydroxymethyl) benzyloxy]- 4-hydroxydiphenyl sulfone, palmitic acid amide, ethylene bisamide, o-toluene sulfonamide, montanic acid wax, di-p-tolyl carbonate, phenyl-α-naphthyl carbonate, 4,4'-ethylenedioxy-bisbenzoic acid di Benzyl ester, methyl p-nitrobenzoate, dibenzoyloxymethane, bis [2- (4- (4-) [Toxyphenoxy) ethyl] ether, methoxycarbonyl-N-stearic acid benzamide, N-benzoylstearic acid amide, N-eicoic acid amide, behenic acid amide, p-acetotoluidide, p-acetophenethylide, N-acetoacetyl-p -Toluidine, dimethyl terephthalate, p-methylthiophenyl benzyl ether, di (β-biphenylethoxy) benzene, p-di (vinyloxyethoxy) benzene, 1-isopropylphenyl-2-phenylethane, 1,4-di (phenylthio) ) Butane, N-stearylstearic acid amide, N-stearylurea, acetoacetate anilide compounds, fatty acid anilide compounds, 2,2'-bis (4-methoxyphenyl) diethyl ether, bis (4-methoxyphenyl) ether, Adipin Acid diphenyl, benzenesulfonic acid phenyl ester, 4-acetylacetophenone, benzamide, thioacetanilide acrylic acid amide, diethyl isophthalate, an equimolar mixture of dibenzyl oxalate and di (4-chlorobenzyl) oxalate, di (4-chlorooxalate) Equal mixture of methyl benzyl) and di (4-chlorobenzyl) oxalate, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'-methylenebis (2,6-di-t -Butylphenol), 4,4'-dimethoxydiphenylsulfone, 2,4'-dimethoxydiphenylsulfone, 1,2-bis (4-methoxyphenylthio) ethane, 1,2-bis (4-methoxyphenoxy) propane, 1 , 3-Phenoxy-2-propanol, 1,4-diphenylthio-2-bute 1,4-Diphenylthiobutane, 1,4-diphenoxy-2-butene, 1,5-bis (4-methoxyphenoxy) -3-oxapentane, 1,3-dibenzoyloxypropane, 4,4′- Ethylenedioxy-2-bisbenzoic acid dibenzyl ester, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-dibenzyloxynaphthalene, 1,4-dimethoxynaphthalene, 1,4-bis (2 -Vinyloxyethoxy) benzene, p- (2-vinyloxyethoxy) biphenyl, p-propargyloxybiphenyl, p-benzyloxybenzyl alcohol, di-β-naphthyl phenylene diamine, diphenylamine, carbazole, 2,3-di-m -Tolylbutane, 4,4'-dimethylbiphenyl, 2,3,5,6-tetramethyl- 4'-Methyldiphenylmethane, 4-acetylbiphenyl, triphenylmethane, phenyl 1-hydroxy-2-naphthoate, methyl 1-hydroxy-2-naphthoate, N-octadecyl-carbamoyl-p-methoxycarbonylbenzene, β -Naphthofunctional acid phenyl, guaiacol carbonate, di-p-tolyl carbonate, phenyl-α-naphthyl carbonate, 1,1-diphenylpropanol, 1,1-diphenylethanol, N-octadecylcarbamoylbenzene, dibenzyl sulfide, amide AP- 1, aluminum stearate, calcium stearate, zinc stearate, zinc palmitate, zinc behenate and the like.

（式中、ａは０〜６の整数である。） Specific examples of the preservative improver used in the present invention include 2,2'-methylenebis (4-methyl-6-t-butylphenol) and 2,2'-methylenebis (4-ethyl-6-t-butylphenol) 2,2,2'-Ethylidenebis (4,6-di-t-butylphenol), 4,4'-thiobis (2-methyl-6-t-butylphenol), 4,4'-butylidenebis (6-t-butyl) -M-cresol), 1- [α-methyl-α- (4'-hydroxyphenyl) ethyl] -4- [α ', α'-bis (4'-hydroxyphenyl) ethyl] benzene, 1,1, 3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, tris (2,6-) Dimethyl-4- -Butyl-3-hydroxybenzyl) isocyanurate, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy-3,3 ', 5,5'-tetrabromodiphenyl sulfone, 4,4' -Dihydroxy-3,3 ', 5,5'-tetramethyldiphenyl sulfone, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3,5) Hindered phenol compounds such as dichlorophenyl) propane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4 '-(2-methylglycidyloxy) diphenyl sulfone, diglycidyl terephthalate, cresol novola -Type epoxy resin, phenol novolac type epoxy resin, epoxy compound such as bisphenol A type epoxy resin, N, N'-di-2-naphthyl-p-phenylenediamine, 2,2'-methylenebis Examples thereof include sodium or polyvalent metal salts of -t-butylphenyl) phosphate, bis (4-ethyleneiminocarbonylaminophenyl) methane and the like. For example, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-butylphenol), 2,2'-ethylidenebis (4,6-di -T-butylphenol), 4,4'-thiobis (2-methyl-6-t-butylphenol), 4,4'-butylidenebis (6-t-butyl-m-cresol), 1- [α-methyl-α -(4'-hydroxyphenyl) ethyl] -4- [α ', α'-bis (4'-hydroxyphenyl) ethyl] benzene, 1,1,3-tris (2-methyl-4-hydroxy-5-) Cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, tris (2,6-dimethyl-4-t-butyl-3-hydroxybenzyl) isocyanate Nurate, 4,4'-thiobis (3-methylphenol), 4,4'-dihydroxy-3,3 ', 5,5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3', 5 , 5'- tetramethyl diphenyl sulfone, 2, 2-bis (4-hydroxy 3,5- dibromophenyl) propane, 2, 2- bis (4-hydroxy 3,5- dichlorophenyl) propane, 2, 2- Hindered phenolic compounds such as bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4'- ( 2-Methyl glycidyloxy) diphenyl sulfone, diglycidyl terephthalate, cresol novolac epoxy resin, phenol novolac Epoxy resin, epoxy compound such as bisphenol A type epoxy resin, N, N'-di-2-naphthyl-p-phenylenediamine, sodium of 2,2'-methylenebis (4,6-di-t-butylphenyl) phosphate Or a polyvalent metal salt, bis (4-ethyleneiminocarbonylaminophenyl) methane, a urea urethane compound (color developing agent UU, etc. made by Chemi-Pro Chemical Co., Ltd.), and a diphenyl sulfone crosslinked compound represented by the following formula (7) The mixture etc. of those are mentioned.

(In the formula, a is an integer of 0 to 6)

  Specific examples of the binder used in the present invention include methyl cellulose, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), carboxyl group modified polyvinyl alcohol, sulfonic acid group modified polyvinyl alcohol, silyl Group-modified polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, polyacrylic acid, starch and derivatives thereof, casein, gelatin, water-soluble isoprene rubber, alkali salt of styrene / maleic anhydride copolymer, iso (or diiso) butylene / maleic anhydride Water-soluble ones such as alkali salts of acid copolymers, or (meth) acrylic acid ester copolymers, styrene / (meth) acrylic acid ester copolymers, polymers Urethane, polyester-based polyurethane, polyether-based polyurethane, polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinylidene chloride, polystyrene, styrene / butadiene (SB) copolymer Combined, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, acrylonitrile / butadiene (NB) copolymer, carboxylated acrylonitrile / butadiene (NB) copolymer, colloidal silica and the like Examples thereof include hydrophobic polymer emulsions such as composite particles of (meth) acrylic resin.

  Specific examples of the filler used in the present invention include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, Urea-formalin resin etc. are mentioned.

  Furthermore, various additives other than the above can be used in the present invention, for example, higher fatty acid metal salts such as zinc stearate and calcium stearate for the purpose of thermal head wear prevention, sticking prevention, etc., oxidation prevention or aging prevention Examples thereof include ultraviolet light absorbers such as phenol derivatives, benzophenone compounds and benzotriazole compounds for imparting effects, various surfactants, antifoam agents, and the like.

Next, the method of preparing the heat-sensitive recording material of the present invention will be described. The developer and the sensitizer used in the present invention are separately crushed and dispersed together with a binder or other additives as required, using a dispersing machine such as a ball mill, attritor or sand mill. (Normally, water is used as a medium when pulverizing or dispersing in a wet manner), the dispersion is mixed to prepare a heat-sensitive recording layer coating solution, and paper (plain paper, wood free paper, coated paper, etc.) can be used The thermal recording material of the present invention is prepared by coating and drying it on a support such as a plastic sheet, synthetic paper or the like with a bar coater, a blade coater or the like so that the dry mass is usually 1 to 20 g / m ² .

In addition, if necessary, an intermediate layer may be provided between the heat-sensitive recording layer and the support, or an overcoat layer (protective layer) may be provided on the heat-sensitive recording layer. The intermediate layer and the overcoat layer (protective layer) are, for example, optionally crushed and dispersed as in the preparation of the heat-sensitive recording layer coating liquid together with the above-mentioned binder or other additives as required. After forming a coating solution for a layer or a coating solution for an overcoat layer (protective layer), it is applied by drying so as to be usually about 0.1 to 10 g / m ² and then dried.

Hereinafter, the present invention will be more specifically described by way of examples, but the present invention is not limited at all by the following examples. In the examples, "parts" is parts by mass and "%" is mass%.
The tracking of the reaction and the mixture of the compound represented by the general formula (1) and the general formula (2) and the compound (5) were evaluated by adjusting the concentration of the evaluation sample adjusted to about 2500 ppm with 0.2 μL (Inc) Inersil ODS-2 (4.6 mm diameter x 15 cm, carrier particle diameter: 5 micrometers) It calculated by HPLC analysis by column oven temperature 40 degreeC and wavelength 254 nm using column. As the mobile phase, eluent A is acetonitrile and eluent B is a 0.05% by volume aqueous solution of ammonium acetate, and the composition of each eluent is A: B = 50: 50 to 90:10 for 20 minutes continuously at a flow rate of 0 minutes. Varying at .4 ml / min.

Synthesis Example 1 Synthesis of Mixture of Compound (3), Compound (4) and Compound (5)
To 50 parts of toluene were added 2.55 parts of 1-amino-2-propanol and 0.093 parts of aniline, and the mixture was stirred at 0 ° C. Thereto, 4.16 parts of phenyl isocyanate diluted with 20 parts of toluene was dropped over 30 minutes. After confirming that the phenyl isocyanate was completely reacted by HPLC, the reaction solution was heated as it is to 90 ° C., 3.11 parts of phenyl isocyanate was added thereto, and the mixture was stirred at the same temperature for 4 hours. After completion of the reaction, the reaction solution is cooled to room temperature, the reaction solution is filtered, and the obtained white solid is washed with 150 parts of toluene and dried by heating, whereby the mixing ratio calculated by the formula (I) from HPLC area% is A mixture of compound (3), compound (4) and compound (5), which is 17:64:19, was obtained.

Synthesis Example 2 Synthesis of Mixture of Compound (3), Compound (4) and Compound (5)-2
To 50 parts of toluene were added 2.55 parts of 1-amino-2-propanol and 0.19 parts of aniline, and the mixture was stirred at 0 ° C. Thereto, 4.29 parts of phenyl isocyanate diluted with 20 parts of toluene was added dropwise over 30 minutes. After confirming that the phenyl isocyanate was completely reacted by HPLC, the reaction solution was heated as it is to 90 ° C., 3.10 parts of phenyl isocyanate was added thereto, and the mixture was stirred at the same temperature for 4 hours. After completion of the reaction, the reaction solution is cooled to room temperature, the reaction solution is filtered, and the obtained white solid is washed with 150 parts of toluene and dried by heating, whereby the mixing ratio calculated by the formula (I) from HPLC area% is A mixture of a compound (3), a compound (4) and a compound (5) which were 15:54:31 was obtained.

Example 1 Preparation of Thermosensitive Recording Material The mixture of the compound (3), the compound (4) and the compound (5) obtained in Synthesis Example 1 was subjected to multi-bead shocker (manufactured by Yasui Instruments Co., Ltd.) according to the following composition. The solution (A) was prepared by grinding and dispersing for 1 hour using model: PV 1001 (S).

[A] Liquid: 15 parts of the mixture of Synthesis Example 1
20 parts of 25% PVA aqueous solution
65 parts of water

A mixture of the following composition is ground and dispersed by a sand grinder using a laser diffraction / scattering particle size distribution measuring device LA-950 (manufactured by HORIBA, Ltd.) to a median particle diameter of 1 μm, and dispersion of a chromogenic compound Liquid [B] was prepared.
Solution B: 35 parts of 3-dibutylamino-6-methyl-7-anilinofluoran
40 parts of a 15% PVA aqueous solution
25 parts of water

Next, each solution obtained above and the following agents are mixed according to the following composition to prepare a heat-sensitive recording layer coating solution, and the dry weight on a high-quality paper with a basis weight of 50 g / m ² is 5 g / m ² The heat-sensitive recording material of the present invention was prepared by coating and drying as follows.
[A] solution 33.3 parts [B] solution 8.6 parts 67% calcium carbonate aqueous dispersion 6.7 parts 15% PVA aqueous solution 20 parts 37% zinc stearate aqueous dispersion 2.7 parts water 18.2 parts

Example 2
A thermosensitive recording material of the present invention was obtained in the same manner as in Example 1 except that the mixture obtained in Synthesis Example 2 was used instead of the mixture obtained in Synthesis Example 1.

Comparative Example 1
A thermosensitive recording material for comparison was obtained in the same manner as in Example 1 except that only the compound (3) was used instead of the mixture obtained in Synthesis Example 1.

Comparative Example 2
A thermosensitive recording material for comparison was obtained in the same manner as in Example 2 except that only the compound (4) was used instead of the mixture obtained in Synthesis Example 1.

Comparative Example 4
A mixture of the following composition is pulverized and dispersed by a sand grinder using a laser diffraction / scattering particle size distribution measuring device LA-950 (manufactured by Horiba, Ltd.) to a median particle diameter of 1 μm, and the [C] liquid is obtained A thermosensitive recording material for comparison was obtained in the same manner as in Example 5 except that among the compositions of the heat-sensitive recording layer coating liquid described in Example 5 that was prepared, the solution [A] was changed to the solution [C]. .
Liquid C: 25 parts of bisphenol S
20 parts of 25% PVA aqueous solution
55 parts of water

[Coloring test]
The heat-sensitive recording materials obtained in Examples 1 and 2 and Comparative Examples 1 to 3 above were printed with a pulse width of 0.9 msec using a thermal printer (TH-M2 / PP) manufactured by Okura Engineering Co., Ltd. The Macbeth reflection density of the coloring portion was measured using a colorimeter manufactured by X-Rite, trade name "eXact". The color was measured under the conditions of illuminant C as the light source, ANSI A as the density standard, and a viewing angle of 2 degrees. The results are shown in Table 3 below. The higher the Macbeth reflection density, the better the color development.

  As apparent from Table 3, in Examples 1 and 2 in which the thermosensitive recording layer contained the compound (3), the compound (4) and the compound (5) at each mixing ratio described above, only the compound (3) was used. The Macbeth reflection density of the printed portion is higher than that of Comparative Example 1 using only the compound (4) or Comparative Example 2 using only the compound (4), and Comparative Example 3 using bisphenol S described in Patent Document 2; Excellent.

[Remaining ratio of print density]
The thermal recording materials obtained in Examples 1 and 2 and Comparative Examples 2 and 3 were printed using a thermal printer (TH-M2 / PP) manufactured by Okura Engineering Co., Ltd. with a pulse width of 1.4 msec. This sample was held at 90 ° C. for 1 hour using a blast constant temperature thermostat made by Yamato Scientific Co., Ltd., trade name DKN402. The Macbeth reflection density of the printed portion was measured using a colorimeter manufactured by X-Rite, trade name "eXact".
The color was measured under the conditions of illuminant C as the light source, ANSI A as the density standard, and a viewing angle of 2 degrees. The results are shown in Table 4 below. The residual ratio of print density was calculated according to the following formula (II).
Residual ratio (%) = [(Macbeth reflection density of printed area after heat resistance test) / (Macbeth reflection density of printed area before heat resistance test)] (II)

As is apparent from Table 4 above, in Examples 1 and 2 in which the thermosensitive recording layer contained the compound (3), the compound (4) and the compound (5) in the above mixing ratio, the printing density before and after the heat resistance test was Since the residual rate of the above is large, the printed portion exhibits extremely high stability to heat as compared with Comparative Examples 1 and 2.

Claims (5)

What is claimed is: 1. A heat-sensitive recording material comprising a compound represented by the following formula (1) or (2) and 1,3-diphenylurea.

[In Formula (1) and Formula (2), A is a C 10 or less bivalent saturated hydrocarbon group which may contain a hetero atom. ] The compound represented by the general formula (1) is a compound represented by the following formula (3), and the compound represented by the general formula (2) is a compound represented by the following formula (4) The heat-sensitive recording material according to item 1.

The mixing ratio of the compound represented by the said General formula (1) and General formula (2), and a 1, 3- diphenyl urea is 10-90: 5-50: 5-80, The said Claim 1 or 2 Thermal recording material. A thermosensitive recording layer comprising the thermosensitive recording material according to any one of claims 1 to 3. A thermosensitive recording paper comprising the thermosensitive recording material or the thermosensitive recording layer according to any one of claims 1 to 4.