JP2017081107A - Thermal recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal recording material excellent in heat resistance of a color developing part.SOLUTION: The thermal recording material contains at least one imidazole based compound as a developing compound, and is combined with a compound represented by general formula (1) in the figure. (In formula (1), Rrepresents an alkyl group that may have substituents.)SELECTED DRAWING: None

Description

  The present invention relates to a heat-sensitive recording material having excellent heat resistance.

  In general, heat-sensitive recording materials are obtained by dispersing a leuco dye and a developing compound such as a phenolic compound in the form of fine particles, and then mixing them together with additives such as a binder, a sensitizer, a filler, and a lubricant. Is applied to paper, film, synthetic paper, etc., and color development is recorded by a chemical reaction that occurs when one or both of the leuco dye and the color developing compound are melted and contacted by heating. Is what you get. For the color development of such a heat-sensitive recording material, a thermal printer or the like with a built-in thermal head is used. Compared with other recording methods, this thermal recording method is (1) no noise during recording, (2) no need for development and fixing, (3) maintenance-free, (4) machine is relatively Due to its low cost, it is widely used in the facsimile field, the output of computers, the field of printers such as calculators, the field of recorders for medical measurement, the field of automatic ticket machines, the field of thermal recording labels, and the like.

  In recent years, the use of thermal recording materials has expanded, and the demand for high-speed recording has further increased in order to further improve productivity, and the development of thermal recording materials with excellent thermal responsiveness that can sufficiently cope with high-speed recording is strongly desired. It is rare. In this case, a color developing compound having a low melting point and a low heat of fusion is required, but this property tends to have a drawback that a background fog occurs at the time of production, use or storage. As described above, not only a high whiteness but also an improvement in stability is desired for an unrecorded portion (background) of the heat-sensitive recording material.

  In general, a color developing compound having a phenolic hydroxyl group has a high color developing ability. Among them, a bisphenol-based color developing compound has, for example, 2,2-bis (4-hydroxy) disclosed in Patent Document 1 because of its high color density. Many reports have been reported, including phenylpropane) (bisphenol A) and 4,4′-dihydroxydiphenylsulfone (bisphenol S) disclosed in Patent Document 2. However, these have a disadvantage that they are inferior in thermal responsiveness due to their high melting points.

  In response to such a request, for example, Patent Document 3 discloses that by combining an imidazole compound and 1,3-diphenylurea, a heat-sensitive recording material having improved color developability and heat resistance of the color development portion can be obtained. However, this heat-sensitive recording material cannot be said to have sufficient heat resistance, and further improvement in heat resistance has been desired.

US Pat. No. 3,539,375 Japanese Patent Laid-Open No. 57-11088 Japanese Patent Application No. 2015-190061

  The object of the present invention is to solve the drawbacks of the prior art. That is, it is to provide a heat-sensitive recording material excellent in heat resistance.

  The present inventors have found that a heat-sensitive recording material having excellent heat resistance can be obtained by combining an imidazole compound and a compound represented by the following general formula (1), and have completed the present invention.

（式（１）中、Ｒ^１はアルキル基を表す。）
［２］一般式（１）において、Ｒ^１が無置換またはアリール基で置換されているアルキル基である事を特徴とする［１］に記載の感熱記録材料、
［３］一般式（１）において、Ｒ^１が無置換のアルキル基である事を特徴とする［１］または［２］に記載の感熱記録材料、
［４］一般式（１）において、Ｒ^１がメチル基またはエチル基である事を特徴とする［１］乃至［３］のいずれか一つに記載の感熱記録材料、
［５］イミダゾール系化合物が２−フェニルイミダゾールであることを特徴とする［１］乃至［４］のいずれか一つに記載の感熱記録材料、
［６］［１］乃至［５］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、
［７］［６］に記載の感熱記録層を含む感熱記録紙、
に関する。 That is, the present invention
[1] A heat-sensitive recording material comprising an imidazole compound and a compound represented by the following general formula (1):

(In formula (1), R ¹ represents an alkyl group.)
[2] The heat-sensitive recording material according to [1], wherein in general formula (1), R ¹ is an alkyl group which is unsubstituted or substituted with an aryl group,
[3] The heat-sensitive recording material according to [1] or [2], wherein in general formula (1), R ¹ is an unsubstituted alkyl group,
[4] The heat-sensitive recording material according to any one of [1] to [3], wherein in the general formula (1), R ¹ is a methyl group or an ethyl group,
[5] The heat-sensitive recording material according to any one of [1] to [4], wherein the imidazole compound is 2-phenylimidazole,
[6] A thermal recording layer containing the thermal recording material according to any one of [1] to [5],
[7] Thermal recording paper including the thermal recording layer according to [6],
About.

  The present invention can provide a heat-sensitive recording material excellent in heat resistance by using an imidazole compound and a compound represented by the above general formula (1) as a color developing compound.

The present invention will be described in detail.
The present invention usually includes a colorless or light-coloring compound, an imidazole compound, and a compound represented by the above general formula (1), and, if necessary, other color developing compounds, sensitizers, and storage stability. The present invention relates to a heat-sensitive recording material containing an improver, and further, binders and fillers described below, and other additives.

  In the present invention, the imidazole compound may be either imidazole (a heterocyclic compound having a nitrogen atom at positions 1 and 3 on a 5-membered ring) or a derivative thereof, and is not particularly limited and is known per se. Can be suitably selected from, for example, 1H-imidazole, 5,6-dimethylbenzimidazole, 2,4,5-triphenylimidazole, 4,5-diphenylimidazole, 4-methyl-2-phenylimidazole, 1-methylimidazole, 2-methylimidazole, 1,2-dimethylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 4,5-dihydro-1H-imidazole, 2,5-dihydro-1H-imidazole, 2,3-dihydro-1H-imida , Tetrahydro-1H-imidazole, imidazolidinone, 2-undecylimidazoline, 2-propyl-2-imidazoline, 2-ethyl-2-imidazoline, imidazolidin-2-one, imidazolidine-2-thione, 2 -Methyl-4,5-dihydro-1H-imidazole, imidazolidine-2,4-dione, 2-thioxoimidazolidin-4-one, imidazolidine-2,4-dithione, hydantoin, 5,5-dimethylhydantoin 5,5-diphenylhydantoin, 5-ureidohydantoin, (2,5-dioxoimidazolidin-4-yl) urea, 2-imino-1-methylimidazolidin-4-one, imidazolidinetrione, 3- ( 1H-imidazol-4-yl) acrylic acid, 2-amino-3- (1H-imidazole) 4-yl) propanoic acid, α-amino-1H-imidazole-4-propanoic acid, 2-amino-3- (1H-imidazol-4-yl) propanoyl, α- (3-aminopropanamido) -1H-imidazole -4-propanoic acid, Nα- (β-alanyl) histidine, 2- (3-aminopropanamido) -3- (1H-imidazol-4-yl) propanoyl, Nα- (β-alanyl) histidyl, α- ( 3-aminopropanamide) -1-methyl-1H-imidazole-5-propanoic acid, Nα- (β-alanyl) -Nπ-methylhistidine, α- (3-aminopropanamido) -2-methyl-1H-imidazole -5-propanoic acid, Nα- (β-alanyl) -2-methylhistidine, α- (4-aminobutanamide) -1H-imidazole-4-propaprop Acid, Nα- (4-aminobutanoyl) histidine, 2- (trimethylammonio) -3- (1H-imidazol-4-yl) propanoate, imidazole-4-ethanamine, 2-cyano-1-methyl-3- (2-{[(5-Methyl-1H-imidazol-4-yl) methyl] sulfanyl} ethyl) guanidine, 1- {2-[(4-chlorophenyl) methoxy] -2- (2,4-dichlorophenyl) ethyl } -1H-imidazole 1- {2- (2,4-dichlorophenyl) -2-[(2,4-dichlorophenyl) methoxy] ethyl) -1H-imidazole, 2-ethyl-3-[(1-methyl-1H -Imidazol-5-yl) methyl] butano-4-lactone, benzimidazole, 2-butyl-1H-imidazole-5-carboxyal Hydride, 5,6-dichloro-1-ethyl-2-methylbenzimidazole, 2-propyl-1H-imidazole-4,5-dicarboxylate diethyl, 1H-imidazole-4,5-dicarboxylate dimethyl, 2-methylimidazole 2-ethylimidazole, 2-heptadecylimidazole, 2- (hydroxymethyl) benzimidazole, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-1-methylimidazole, 1-methylimidazole 2-methylimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, 2- (methylthio) benzimidazole, 2-methyl-1-vinylimidazole, 2-propylimidazole, imidazole-4-carboxyal Hydride, 2-phenylimidazole-4-carboxaldehyde, imidazole-2-carboxaldehyde, imidazole-4-carboxylic acid, imidazole-4-dithiocarboxylic acid, imidazole-4-thiocarboxylic acid amide, hydantoin, and the like. 1H-imidazole, 2,4,5-triphenylimidazole, 4,5-diphenylimidazole, imidazolidine-2,4-dione, benzimidazole, 1-benzyl-2-methylimidazole, 2-butyl-1H-imidazole- 5-carboxaldehyde, 5,6-dichloro-1-ethyl-2-methylbenzimidazole, 2-propyl-1H-imidazole-4,5-dicarboxylate diethyl, 1H-imidazole-4,5-dicarboxylate dimethyl, 2 -Ethylimi Dazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 2- (hydroxymethyl) benzimidazole, 2-mercaptobenzimidazole, 2-mercapto-5-methylbenzimidazole, 2-mercapto-1-methylimidazole 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 4-methyl-2-phenylimidazole, 2- (methylthio) benzimidazole, 2-methyl-1-vinylimidazole, 2-propylimidazole, imidazole-4 Carboxaldehyde, 2-phenylimidazole-4-carboxaldehyde, imidazole-2-carboxaldehyde, imidazole-4-carboxylic acid, imidazole-4-dithiocarboxylic acid, imidazole-4- Okarubon acid amides are preferred, 2-phenylimidazole, 4-methyl-2-phenylimidazole, 4,5-dimethyl-2-phenylimidazole, 2- (4-methylphenyl) imidazole, benzimidazole, hydantoin is especially preferred.

Examples of the alkyl group in R ¹ of the formula (1) include a linear, branched or cyclic alkyl group. Among these, a straight chain or a branched chain is preferable, and a straight chain is more preferable. The range of the carbon number is usually C1 to C12, preferably C1 to C8, more preferably C1 to C6, and still more preferably C1 to C4. Specific examples thereof include linear chains such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl. Alkyl groups; branched chain alkyl groups such as isopropyl, isobutyl, sec-butyl, t-butyl, isopentyl, isohexyl, and isooctyl; cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl;

R ^{1 in} formula (1) may have a substituent, and specific examples thereof are as follows, but are not limited thereto.
That is,

  An aryl group, preferably a C6-C12 aryl group (specific examples include phenyl, naphthyl, biphenyl, etc.);

  A 5- or 6-membered heterocyclic group containing 1 to 3 atoms selected from a nitrogen atom, an oxygen atom or a sulfur atom as a ring-constituting atom (preferably the heterocyclic moiety is aromatic. Specific examples include: 5-membered cycloaliphatic such as pyrrolidinyl, tetrahydrofuryl, tetrahydrothiophen-2-yl, tetrahydrothiophen-3-yl; 6-membered cycloaliphatic such as piperidinyl, piperazinyl, dioxan-2-yl, morpholinyl, thiomorpholinyl Aromatic 5-membered rings such as pyrrole, pyrazole, imidazole, triazole, furyl, thiophen-2-yl, thiophen-3-yl, oxazole, thiazole, etc .; Aromatic 6-membered rings such as pyridine, pyrazine, pyridazine, triazine Of these, the ring atoms are nitrogen atoms, Preferably it is selected from nitrogen atom;

  A 5- or 6-membered heterocyclic amino group containing 1 to 3 atoms selected from a nitrogen atom, an oxygen atom or a sulfur atom as a ring-constituting atom (preferably the heterocyclic moiety is aromatic, As pyrrolidinylamino, tetrahydrofurylamino, tetrahydrothiophen-2-ylamino, tetrahydrothiophen-3-ylamino and the like; piperidinylamino, piperazinylamino, dioxan-2-ylamino , Morpholinylamino, thiomorpholinylamino, and the like; pyrroleamino, pyrazoleamino, imidazolamino, triazoleamino, furylamino, thiophen-2-ylamino, thiophen-3-ylamino, oxazoleamino Aromatic 5-membered rings such as thiazoleamino; pyridylami , Pyrazylamino, pyridazinylamino, triazinylamino and the like having 6-membered aromatic rings; and the like, among them, the ring-constituting atoms are selected from nitrogen atoms or sulfur atoms Are preferred;

  A condensed 5- or 6-membered ring in which one benzene ring is condensed to a 5- or 6-membered ring containing 1 to 3 atoms selected from a nitrogen atom, an oxygen atom or a sulfur atom as a ring-constituting atom Heterocyclic amino group (preferably the heterocyclic moiety is aromatic, and specific examples include a 5-membered alicyclic heterocyclic moiety such as phthalanylamino; a 6-membered heterocyclic moiety such as benzopyranylamino; Alicyclic ones: benzpyrrololamino, benzpyrazoleamino, benzimidazolamino, benzotriazoleamino, benzofuranylamino, benzothiophen-2-ylamino, benzothiophen-3-ylamino, benzoxazoleamino, benzothiazoleamino, etc. In which the heterocyclic moiety is an aromatic 5-membered ring; quinolinylamino, cinnolinylamino, phthalazinylamino, quinazolin A heterocyclic moiety such as ruamino, quinoxalinylamino and the like having an aromatic 6-membered ring; and the like.) Among the above, the ring-constituting atom is selected from a nitrogen atom or a sulfur atom. preferable;

  A linear, branched or cyclic alkoxy group, preferably a C1-C10 alkoxy group (specific examples include methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexyloxy, n-heptoxy, n- Straight chain such as octyloxy, n-nonyloxy, n-decyloxy; isopropoxy, isobutoxy, sec-butoxy, t-butoxy, isoamyloxy, t-amyloxy, isohexyloxy, t-hexyloxy, isoheptoxy, t-heptoxy, isooctyloxy, t A branched chain (preferably C3 to C10) such as octyloxy, 2-ethylhexyloxy, isononyloxy, isodecyloxy; cyclic such as cyclopropoxy, cyclobutoxy, cyclopentoxy, cyclohexyloxy, cycloheptoxy (preferably C3 to C ) Ones; preferably an alkoxy group having a linear or branched chain).;

An aryloxy group, preferably a C6-C12 aryloxy group (specific examples include phenoxy, naphthyloxy, biphenyloxy and the like);
Linear, branched or cyclic alkylcarbonylamino group, preferably C1-C10 alkylcarbonylamino group (specific examples include methylcarbonylamino, ethylcarbonylamino, n-propylcarbonylamino, n-butylcarbonylamino, n- Straight chain such as pentylcarbonylamino, n-hexylcarbonylamino, n-heptylcarbonylamino, n-octylcarbonylamino, n-nonylcarbonylamino, n-decylcarbonylamino; isopropylcarbonylamino, isobutylcarbonylamino, sec- Butylcarbonylamino, t-butylcarbonylamino, isoamylcarbonylamino, t-amylcarbonylamino, isohexylcarbonylamino, t-hexylcarbonylamino, isoheptylcarbo A branched chain (preferably C3 to C10) such as ruamino, t-heptylcarbonylamino, isooctylcarbonylamino, t-octylcarbonylamino, 2-ethylhexylcarbonylamino, isononylcarbonylamino, isodecylcarbonylamino; cyclopropyl Cyclic (preferably C3-C7) such as carbonylamino, cyclobutylcarbonylamino, cyclopentylcarbonylamino, cyclohexylcarbonylamino, cycloheptylcarbonylamino; preferably linear or branched alkylcarbonylamino group, more preferably straight Chain alkylcarbonylamino groups));

  An arylcarbonylamino group, preferably a C6-C12 arylcarbonylamino group (specific examples include phenylcarbonylamino, naphthylcarbonylamino, biphenylcarbonylamino, etc.);

  A linear, branched or cyclic alkylcarbonyloxy group, preferably a C1-C10 alkylcarbonyloxy group (specific examples include methylcarbonyloxy, ethylcarbonyloxy, n-propylcarbonyloxy, n-butylcarbonyloxy, n- Linear compounds such as pentylcarbonyloxy, n-hexylcarbonyloxy, n-heptylcarbonyloxy, n-octylcarbonyloxy, n-nonylcarbonyloxy, n-decylcarbonyloxy; isopropylcarbonyloxy, isobutylcarbonyloxy, sec- Butylcarbonyloxy, t-butylcarbonyloxy, isoamylcarbonyloxy, t-amylcarbonyloxy, isohexylcarbonyloxy, t-hexylcarbonyloxy, isoheptylcarbo A branched chain (preferably C3 to C10) such as ruoxy, t-heptylcarbonyloxy, isooctylcarbonyloxy, t-octylcarbonyloxy, 2-ethylhexylcarbonyloxy, isononylcarbonyloxy, isodecylcarbonyloxy, etc .; cyclopropyl Cyclic (preferably C3 to C7) such as carbonyloxy, cyclobutylcarbonyloxy, cyclopentylcarbonyloxy, cyclohexylcarbonyloxy, cycloheptylcarbonyloxy; among them, a linear or branched alkylcarbonyloxy group is preferable, An alkylcarbonyloxy group is more preferred.); An arylcarbonyloxy group, preferably a C6-C12 arylcarbonyloxy group (specific examples include phenylcarbonyloxy, Chill carbonyloxy, biphenyl carbonyloxy, etc.).;

  Linear, branched or cyclic alkylcarbonyl group, preferably C1-C10 alkylcarbonyl group (specific examples include methylcarbonyl, ethylcarbonyl, n-propylcarbonyl, n-butylcarbonyl, n-pentylcarbonyl, n-hexyl) Straight chain such as carbonyl, n-heptylcarbonyl, n-octylcarbonyl, n-nonylcarbonyl, n-decylcarbonyl; isopropylcarbonyl, isobutylcarbonyl, sec-butylcarbonyl, t-butylcarbonyl, isoamylcarbonyl, t-amyl Carbonyl, isohexylcarbonyl, t-hexylcarbonyl, isoheptylcarbonyl, t-heptylcarbonyl, isooctylcarbonyl, t-octylcarbonyl, 2-ethylhexylcarbonyl, isononylcarbonyl A branched chain (preferably C3 to C10) such as bonyl, isodecylcarbonyl; cyclic (preferably C3 to C7) such as cyclopropylcarbonyl, cyclobutylcarbonyl, cyclopentylcarbonyl, cyclohexylcarbonyl, cycloheptylcarbonyl; A linear or branched alkylcarbonyl group is preferred, and a linear alkylcarbonyl group is more preferred);

  An arylcarbonyl group, preferably a C6-C12 arylcarbonyl group (specific examples include phenylcarbonyl (benzoyl), naphthylcarbonyl, biphenylcarbonyl, etc.);

A carbamoyl group;
A linear, branched or cyclic monoalkylcarbamoyl group, preferably a mono-C1 to C10 alkylcarbamoyl group (specific examples include methylcarbamoyl, ethylcarbamoyl, n-propylcarbamoyl, n-butylcarbamoyl, n-pentylcarbamoyl, n Straight chain such as -hexylcarbamoyl, n-heptylcarbamoyl, n-octylcarbamoyl, n-nonylcarbamoyl, n-decylcarbamoyl; isopropylcarbamoyl, isobutylcarbamoyl, sec-butylcarbamoyl, t-butylcarbamoyl, isoamylcarbamoyl, t- Amylcarbamoyl, isohexylcarbamoyl, t-hexylcarbamoyl, isoheptylcarbamoyl, t-heptylcarbamoyl, isooctylcarbamoyl, t-octy A branched chain (preferably C3 to C10) such as carbamoyl, 2-ethylhexylcarbamoyl, isononylcarbamoyl, isodecylcarbamoyl; cyclic such as cyclopropylcarbamoyl, cyclobutylcarbamoyl, cyclopentylcarbamoyl, cyclohexylcarbamoyl, cycloheptylcarbamoyl C3 to C7); preferably linear or branched, more preferably linear));

  A linear, branched or cyclic dialkylcarbamoyl group, preferably a diC1-C10 alkylcarbamoyl group (specific examples include dimethylcarbamoyl, diethylcarbamoyl, di-n-propylcarbamoyl, di-n-butylcarbamoyl, di-n -Straight chain such as pentylcarbamoyl, di-n-hexylcarbamoyl, di-n-heptylcarbamoyl, di-n-octylcarbamoyl, di-n-nonylcarbamoyl, di-n-decylcarbamoyl; diisopropylcarbamoyl, diisobutylcarbamoyl, Di-sec-butylcarbamoyl, di-t-butylcarbamoyl, diisoamylcarbamoyl, di-t-amylcarbamoyl, diisohexylcarbamoyl, di-t-hexylcarbamoyl, diisoheptylcarbamoyl, di- -Branched chains such as heptylcarbamoyl, diisooctylcarbamoyl, di-t-octylcarbamoyl, di- (2-ethylhexyl) carbamoyl, diisononylcarbamoyl, diisodecylcarbamoyl (preferably having two C3-C10 branched chains) Cyclic (preferably having two C3-C7 cyclic groups) such as dicyclopropylcarbamoyl, dicyclobutylcarbamoyl, dicyclopentylcarbamoyl, dicyclohexylcarbamoyl, dicycloheptylcarbamoyl; preferably linear or branched , More preferably a linear one).

  A monoarylcarbamoyl group, preferably a mono C6-C12 arylcarbamoyl group (specific examples include phenylcarbamoyl, naphthylcarbamoyl, biphenylcarbamoyl, etc.);

  A diarylcarbamoyl group, preferably a diC6-C12 arylcarbamoyl group (specific examples include diphenylcarbamoyl, dinaphthylcarbamoyl, di (biphenyl) carbamoyl);

  A linear, branched or cyclic alkoxycarbonyl group, preferably a C1-C10 alkoxycarbonyl group (specific examples include methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, n-butoxycarbonyl, n-pentoxycarbonyl, n- Straight chain such as hexyloxycarbonyl, n-heptoxycarbonyl, n-octyloxycarbonyl, n-nonyloxycarbonyl, n-decyloxycarbonyl; isopropoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, t-butoxycarbonyl , Isoamyloxycarbonyl, t-amyloxycarbonyl, isohexyloxycarbonyl, t-hexyloxycarbonyl, isoheptoxycarbonyl, t-heptoxycarbonyl, isooctyloxycarbonyl, A branched chain (preferably C3 to C10) such as octyloxycarbonyl, 2-ethylhexyloxycarbonyl, isononyloxycarbonyl, isodecyloxycarbonyl; cyclopropoxycarbonyl, cyclobutoxycarbonyl, cyclopentoxycarbonyl, cyclohexyloxy Cyclic (preferably C3 to C7) such as carbonyl and cycloheptoxycarbonyl; preferably linear or branched, more preferably linear.);

  An aryloxycarbonyl group, preferably a C6-C12 aryloxycarbonyl group (specific examples include phenoxycarbonyl, naphthyloxycarbonyl, biphenyloxycarbonyl and the like);

  Linear, branched or cyclic alkylsulfonylamino group, preferably C1-C10 alkylsulfonylamino group (specific examples include methylsulfonylamino, ethylsulfonylamino, n-propylsulfonylamino, n-butylsulfonylamino, n- Straight chain such as pentylsulfonylamino, n-hexylsulfonylamino, n-heptylsulfonylamino, n-octylsulfonylamino, n-nonylsulfonylamino, n-decylsulfonylamino; isopropylsulfonylamino, isobutylsulfonylamino, sec-butyl Sulfonylamino, t-butylsulfonylamino, isoamylsulfonylamino, t-amylsulfonylamino, isohexylsulfonylamino, t-hexylsulfonylamino, isoheptylsulfur A branched chain (preferably C3 to C10) such as nylamino, t-heptylsulfonylamino, isooctylsulfonylamino, t-octylsulfonylamino, 2-ethylhexylsulfonylamino, isononylsulfonylamino, isodecylsulfonylamino; cyclopropyl Cyclic (preferably C3-C7) such as sulfonylamino, cyclobutylsulfonylamino, cyclopentylsulfonylamino, cyclohexylsulfonylamino, cycloheptylsulfonylamino; preferably linear or branched, more preferably linear );

  An arylsulfonylamino group, preferably a C6-C12 arylsulfonylamino group (specific examples include phenylsulfonylamino, toluenesulfonylamino, naphthylsulfonylamino, biphenylsulfonylamino, etc.);

A sulfamoyl group;
A linear, branched or cyclic monoalkylsulfamoyl group, preferably a mono-C1-C10 alkylsulfamoyl group (specific examples include methylsulfamoyl, ethylsulfamoyl, n-propylsulfamoyl, n Linear chain such as -butylsulfamoyl, n-pentylsulfamoyl, n-hexylsulfamoyl, n-heptylsulfamoyl, n-octylsulfamoyl, n-nonylsulfamoyl, n-decylsulfamoyl Isopropylsulfamoyl, isobutylsulfamoyl, sec-butylsulfamoyl, t-butylsulfamoyl, isoamylsulfamoyl, t-amylsulfamoyl, isohexylsulfamoyl, t-hexylsulfa Moyl, isoheptyl sulfamoyl, t-heptyl sulf A branched chain (preferably C3 to C10) such as moyl, isooctylsulfamoyl, t-octylsulfamoyl, 2-ethylhexylsulfamoyl, isononylsulfamoyl, isodecylsulfamoyl; cyclopropylsulfa Cyclic (preferably C3 to C7) such as moyl, cyclobutylsulfamoyl, cyclopentylsulfamoyl, cyclohexylsulfamoyl, cycloheptylsulfamoyl; preferably linear or branched, more preferably straight Chain));

  A linear, branched or cyclic dialkylsulfamoyl group, preferably a diC1-C10 alkylsulfamoyl group (specific examples include dimethylsulfamoyl, diethylsulfamoyl, di-n-propylsulfamoyl, Di-n-butylsulfamoyl, di-n-pentylsulfamoyl, di-n-hexylsulfamoyl, di-n-heptylsulfamoyl, di-n-octylsulfamoyl, di-n-no Straight chain such as nylsulfamoyl, di-n-decylsulfamoyl; diisopropylsulfamoyl, diisobutylsulfamoyl, di-sec-butylsulfamoyl, di-t-butylsulfamoyl, diisoamylsulfa Moyl, di-t-amylsulfamoyl, diisohexylsulfamoyl, di-t-hexylsulfa Yl, diisoheptylsulfamoyl, di-t-heptylsulfamoyl, diisooctylsulfamoyl, di-t-octylsulfamoyl, di- (2-ethylhexyl) sulfamoyl, diisononylsulfamoyl, diisodecylsulfur Branched chain such as famoyl (preferably having two C3 to C10 branched chains); dicyclopropylsulfamoyl, dicyclobutylsulfamoyl, dicyclopentylsulfamoyl, dicyclohexylsulfamoyl, dicyclo Cyclic (preferably having two C3-C7 cyclic groups) such as heptylsulfamoyl; preferably linear or branched, more preferably linear).

  A monoarylsulfamoyl group, preferably a mono C6-C12 arylsulfamoyl group (specific examples include phenylsulfamoyl, naphthylsulfamoyl, biphenylsulfamoyl and the like);

  A diarylsulfamoyl group, preferably a di-C6-C12 arylsulfamoyl group (specific examples include diphenylsulfamoyl, dinaphthylsulfamoyl, di (biphenyl) sulfamoyl, etc.);

  Linear, branched or cyclic alkylsulfonyl group, preferably C1-C12 alkylsulfonyl group (specific examples include methylsulfonyl, ethylsulfonyl, n-propylsulfonyl, n-butylsulfonyl, n-pentylsulfonyl, n-hexyl) Straight chain such as sulfonyl, n-heptylsulfonyl, n-octylsulfonyl, n-nonylsulfonyl, n-decylsulfonyl, n-undecylsulfonyl, n-dodecylsulfonyl; isopropylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl, t -Butylsulfonyl, isoamylsulfonyl, t-amylsulfonyl, isohexylsulfonyl, t-hexylsulfonyl, isoheptylsulfonyl, t-heptylsulfonyl, isooctylsulfonyl, t-octyls A branched chain (preferably C3 to C12) such as phonyl, 2-ethylhexylsulfonyl, isononylsulfonyl, isodecylsulfonyl, isoundecylsulfonyl, t-undecylsulfonyl, isododecylsulfonyl, t-dodecylsulfonyl, etc .; cyclopropyl Cyclic (preferably C3-C7) such as sulfonyl, cyclobutylsulfonyl, cyclopentylsulfonyl, cyclohexylsulfonyl, cycloheptylsulfonyl; preferably linear or branched, more preferably linear. ;

  An arylsulfonyl group, a C6-C12 arylsulfonyl group (specific examples include phenylsulfonyl, naphthylsulfonyl, biphenylsulfonyl, etc.);

  Linear, branched or cyclic alkylthio group, preferably C1-C10 alkylthio group (specific examples include methylthio, ethylthio, n-propylthio, n-butylthio, n-pentylthio, n-hexylthio, n-heptylthio, n- Straight chain such as octylthio, n-nonylthio, n-decylthio; isopropylthio, isobutylthio, sec-butylthio, t-butylthio, isoamylthio, t-amylthio, isohexylthio, t-hexylthio, isoheptylthio, t-heptylthio, A branched chain (preferably C3 to C10) such as isooctylthio, t-octylthio, 2-ethylhexylthio, isononylthio, isodecylthio; cyclopropylthio, cyclobutylthio, cyclopentylthio, cyclohexylthio, cyclohexane Cyclic such Chiruchio (preferably C3-C7) ones; those preferably linear or branched chain, or more preferably a straight chain).;

  An arylthio group, preferably a C6-C12 arylthio group (specific examples include phenylthio, naphthylthio, biphenylthio and the like);

Ureido group;
A linear, branched or cyclic monoalkylureido group, preferably a mono C1-C10 alkylureido group (specific examples include methylureido, ethylureido, n-propylureido, n-butylureido, n-pentylureido, n A straight chain such as hexylureido, n-heptylureido, n-octylureido, n-nonylureido, n-decylureido; isopropylureido, isobutylureido, sec-butylureido, t-butylureido, isoamylureido, t-amylureido, Branched chains such as isohexylureido, t-hexylureido, isoheptylureido, t-heptylureido, isooctylureido, t-octylureido, 2-ethylhexylureido, isononylureido, isodecylureido, etc. C3-C10); cyclic (preferably C3-C7) such as cyclopropylureido, cyclobutylureido, cyclopentylureido, cyclohexylureido, cycloheptylureido; preferably linear or branched Preferably a straight chain is mentioned.);

  Linear, branched or cyclic dialkylureido groups, preferably diC1-C10 alkylureido groups (specific examples include dimethylureido, diethylureido, di-n-propylureido, di-n-butylureido, di-n -Straight chain such as pentylureido, di-n-hexylureido, di-n-heptylureido, di-n-octylureido, di-n-nonylureido, di-n-decylureido; diisopropylureido, diisobutylureido, di- sec-butylureido, di-t-butylureido, diisoamylureido, di-t-amylureido, diisohexylureido, di-t-hexylureido, diisoheptylureido, di-t-heptylureido, diisooctylureido , Di-t-octylureido, di- (2-e Ruhexyl) having a branched chain such as ureido, diisononylureido, diisodecylureido (preferably having two C3 to C10 branched chains); dicyclopropylureido, dicyclobutylureido, dicyclopentylureido, dicyclohexylureido, dicycloheptyl Cyclic (preferably having two C3-C7 cyclic groups) such as ureido; preferably linear or branched, and more preferably linear.

  A monoarylureido group, preferably a mono C6-C12 arylureido group (specific examples include phenylureido, naphthylureido, biphenylureido, etc.);

  A diarylureido group, preferably a di-C6-C12 arylureido group (specific examples include diphenylureido, dinaphthylureido, di (biphenyl) ureido);

  Linear, branched or cyclic alkoxycarbonylamino group, preferably C1-C10 alkoxycarbonylamino group (specific examples include methoxycarbonylamino, ethoxycarbonylamino, n-propoxycarbonylamino, n-butoxycarbonylamino, n- Straight chain such as pentoxycarbonylamino, n-hexyloxycarbonylamino, n-heptoxycarbonylamino, n-octyloxycarbonylamino, n-nonyloxycarbonylamino, n-decyloxycarbonylamino; isopropoxycarbonylamino, Isobutoxycarbonylamino, sec-butoxycarbonylamino, t-butoxycarbonylamino, isoamyloxycarbonylamino, t-amyloxycarbonylamino, isohexyloxycarbonyla , T-hexyloxycarbonylamino, isoheptoxycarbonylamino, t-heptoxycarbonylamino, isooctyloxycarbonylamino, t-octyloxycarbonylamino, 2-ethylhexyloxycarbonylamino, isononyloxycarbonylamino, iso Branched chain such as decyloxycarbonylamino (preferably C3-C10); cyclic such as cyclopropoxycarbonylamino, cyclobutoxycarbonylamino, cyclopentoxycarbonylamino, cyclohexyloxycarbonylamino, cycloheptoxycarbonylamino (preferably C3-C7); preferably linear or branched, more preferably linear));

  An aryloxycarbonylamino group, preferably a C6-C12 aryloxycarbonylamino group (specific examples include phenylcarbonylamino, naphthylcarbonylamino, biphenylcarbonylamino, etc.);

  A linear, branched or cyclic monoalkylamino group, preferably a mono-C1-C10 alkylamino group (specific examples include methylamino, ethylamino, n-propylamino, n-butylamino, n-pentylamino, n Straight chain such as -hexylamino, n-heptylamino, n-octylamino, n-nonylamino, n-decylamino; isopropylamino, isobutylamino, sec-butylamino, t-butylamino, isoamylamino, t-amylamino, Branched chain such as isohexylamino, t-hexylamino, isoheptylamino, t-heptylamino, isooctylamino, t-octylamino, 2-ethylhexylamino, isononylamino, isodecylamino (preferably C3 to C10) Cyclopropylamino, Robuchiruamino, cyclopentylamino, those cyclohexylamino, annular, etc. cycloheptylamino (preferably C3-C7); those preferably a straight chain or branched chain, or more preferably a straight chain).;

  Linear, branched or cyclic dialkylamino group, preferably diC1-C10 alkylamino group (specific examples include dimethylamino, diethylamino, di-n-propylamino, di-n-butylamino, di-n- Straight chain such as pentylamino, di-n-hexylamino, di-n-heptylamino, di-n-octylamino, di-n-nonylamino, di-n-decylamino; diisopropylamino, diisobutylamino, di-sec -Butylamino, di-t-butylamino, diisoamylamino, di-t-amylamino, diisohexylamino, di-t-hexylamino, diisoheptylamino, di-t-heptylamino, diisooctylamino, Di-t-octylamino, di- (2-ethylhexyl) amino, diisononylamino, diiso A branched chain such as silamino (preferably having two C3 to C10 branched chains); cyclic such as dicyclopropylamino, dicyclobutylamino, dicyclopentylamino, dicyclohexylamino, dicycloheptylamino, etc. (preferably C3 ˜C7 cyclic groups); preferably linear or branched, more preferably linear).

  An arylamino group (monoarylamino group or diarylamino group, preferably a mono C6-C12 arylamino group) is a mono C6-C12 arylamino group (specific examples include phenylamino (anilino), naphthylamino, biphenylamino, etc.) Similarly, as the arylamino group, a di-C6-C12 arylamino group (specific examples include diphenylamino, dinaphthylamino, di (biphenyl) amino, etc.);

  Mercapto group (in this specification, meaning a group represented by “—SH”); halogen atom (specific examples include fluorine atom, chlorine atom, bromine atom; preferably fluorine atom, chlorine atom, bromine atom) An atom)); a hydroxy group, a cyano group, a nitro group, an amino group, a carboxy group, and the like.

The above substituents for R ¹ may have one or two groups, preferably one further, selected from these substituents.

In R ¹ , the alkyl group which may have a substituent is preferably unsubstituted or substituted with an aryl group, and particularly preferably unsubstituted.

R ¹ is preferably a methyl group or an ethyl group.

Specific examples of the compounds in the present invention can be given in the following Tables 1-1 to 1-3, but are not limited thereto.

  Next, although the manufacturing method of the compound shown by General formula (1) used for this invention is demonstrated, it can manufacture by the well-known method shown below, for example. In addition, the compound represented by the general formula (1) can be appropriately selected from known compounds per se, and commercially available compounds may be used.

（式中、Ｒ^１は前記と同義である。） [Production method]

(In the formula, R ¹ has the same meaning as described above.)

  The compound of the above formula (1-2) can be produced by reacting o-phenylenediamine of the formula (1-1) with an acid halide or acid anhydride in the presence or absence of a base.

  The solvent used in this reaction 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, and dichloroethane; aromatic hydrocarbon compounds such as benzene, toluene, and xylene; ether compounds such as dioxane, tetrahydrofuran, anisole, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether Nitrile compounds such as acetonitrile; ketone compounds such as acetone and 2-butanone; ester compounds such as ethyl acetate and butyl acetate; sulfone compounds such as sulfolane; ; Sulfoxide compounds such as dimethyl sulfoxide and the like, may be used which are mixed.

  Examples of the acid halide used in this reaction include acetyl chloride, propinoyl chloride, isobutyryl chloride, propionyl chloride, pivaloyl chloride, butyryl chloride, 2,2-dimethylylbutyryl chloride, isovaleryl chloride. Etc. The usage-amount of an acid halide is 0.1-50 times mole with respect to 1 mol of o-phenylenediamine of Formula (1-1), and 0.1-5 times mole is preferable.

（式中、Ｒ^１は前記と同義である。） In general, an acid halide can be produced by reacting a compound of the following general formula (1-3) with thionyl chloride or oxanyl chloride.

(In the formula, R ¹ has the same meaning as described above.)

  Examples of acid anhydrides used in this reaction include acetic anhydride. The usage-amount of an acid anhydride is 0.1-50 times mole with respect to 1 mol of o-phenylenediamine of Formula (1-1), and 1-5 times mole is preferable.

  Examples of the base that is optionally used in this reaction include inorganic bases such as sodium bicarbonate, sodium carbonate, potassium carbonate, and cesium carbonate; and organic bases such as triethylamine, pyridine, and diisopropylethylamine. The usage-amount of a base should just be 0.1-50 times mole with respect to 1 mol of o-phenylenediamine of Formula (1-1), Preferably it may be 1-5 times mole.

  The reaction temperature of this reaction is usually −78 to 100 ° C., preferably 0 to 80 ° C. The reaction may be performed for 10 minutes to 24 hours.

  In forming the heat-sensitive recording material in the present invention, the color-forming compound contained in the heat-sensitive recording material is usually 1 to 50% by weight, preferably 5 to 30% by weight, and the imidazole compound is usually 1 to 70% by weight, preferably 10 to 50% by weight, the compound represented by the above formula (1) is usually 1 to 70% by weight, preferably 1 to 50% by weight, the sensitizer is 1 to 80% by weight, and the binder is usually 1 to 90% by weight. %, Filler is usually 0 to 80% by weight, and other lubricants, surfactants, antifoaming agents, and UV absorbers are each used in an arbitrary ratio, for example, usually 0 to 30% by weight (weight% is heat sensitive). The weight ratio of each component in the recording material). As a more preferable embodiment, in these compositions, the imidazole compound is usually 0.5 to 20 times, more preferably 1 to 5 times, expressed by the above general formula (1) with respect to the chromogenic compound 1. The compound is used in a weight ratio range of usually 0.5 to 20 times, more preferably 0.5 to 5 times that of the chromogenic compound 1. Further, the mixing ratio of the imidazole compound and the compound represented by the general formula (1) is usually 9: 1 to 5: 5 by weight, and preferably 8: 2 to 6: 4. In the heat-sensitive recording material of the present invention, a known color developing compound, a sensitizer, or other additives may be used in combination other than the above components.

  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 heat-sensitive recording paper. Examples of the chromogenic compound used include fluoran compounds, triarylmethane compounds, spiro compounds, diphenylmethane compounds, thiazine compounds, lactam compounds, and fluorene compounds, with fluorane compounds being preferred.

  Specific examples of the fluorane compound include 3-diethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3- (N-methyl-N- Cyclohexylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isopentylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isobutyl) Amino) -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-me Ru-7-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) fluorane, 3- [N-ethyl-N- (p-tolyl) amino] -6-methyl-7-anilinofluorane, 3- Diethylamino-6-methyl-7- (p-toluidino) fluorane, 3-diethylamino-7- (o-chloroanilino) fluorane, 3-dibutylamino-7- (o-chloroanilino) fluorane, 3-diethylamino-7- (o -Fluoroanilino) fluorane, 3-dibutylamino-7- (o-fluoroanilino) fluorane, 3-diethylamino-7- 3,4-dichloroanilino) fluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-diethylamino-6-chloro-7-ethoxyethylaminofluorane, 3-diethylamino-6-chloro-7 -Anilinofluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7-octylfluorane, 3- [N-ethyl-N- (p-tolyl) Amino] -6-methyl-7-phenethylfluorane and the like, and 3-dibutylamino-6-methyl-7-anilinofluorane is preferred.

  Specific examples of triarylmethane compounds include, for example, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone or CVL), 3,3-bis (p-dimethyl). Aminophenyl) 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 Dimethylaminophthalide, 3,3-bis (1,2-dimethylindol-3-yl) -6-dimethylaminophthalide, 3,3-bis 9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3- (2-phenylindol-3-yl) -5-dimethylaminophthalide, 3-p-dimethylaminophenyl-3- ( 1-methylpyrrol-2-yl) -6-dimethylaminophthalide and the like.

  Specific examples of the spiro compound include, for example, 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3′-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-propylspirobenzo. Pyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 1,3,3-trimethyl-6-nitro-8′-methoxyspiro (indoline-2,2′-benzopyran), etc .; specific examples of diphenylmethane compounds Are, for example, N-halophenyl-leucooramine, 4,4-bis-dimethylaminophenylbenzhydrylbenzyl ether, N-2,4,5-trichlorophenylleucooramine, and the like. Specific examples of thiazine compounds include For example, benzoylleucomethylene blue, p-nitrobenzoylleucome Specific examples of lactam compounds include, for example, rhodamine B anilinolactam, rhodamine Bp-chloroanilinolactam, etc .; specific examples of fluorene compounds include, for example, 3,6-bis (dimethylamino) fluorene Spiro (9,3 ′)-6′-dimethylaminophthalide, 3,6-bis (dimethylamino) fluorene spiro (9,3 ′)-6′-pyrrolidinophthalide, 3-dimethylamino-6-diethylamino Fluorene spiro (9,3 ′)-6′-pyrrolidinophthalide and the like. These color forming compounds are used alone or in combination.

  The color developing compound that can be used in combination with the present invention is not particularly limited as long as it is generally used for pressure-sensitive recording paper or heat-sensitive recording paper. For example, α-naphthol, β-naphthol, p-octylphenol 4-tert-octylphenol, pt-butylphenol, p-phenylphenol, 1,1-bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) propane (also known as bisphenol A or BPA) ), 2,2-bis (p-hydroxyphenyl) butane, 1,1-bis (p-hydroxyphenyl) cyclohexane, 4,4′-thiobisphenol, 4,4′-cyclo-hexylidene diphenol, 2, 2′-bis (2,5-dibromo-4-hydroxyphenyl) propane, 4,4′-isopropylidenebis ( 2-t-butylphenol), 2,2′-methylenebis (4-chlorophenol), 4,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-methoxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4 -Hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-ethoxydiphenylsulfone, 4-hydroxy-4'-butoxydiphenylsulfone, 4-hydroxy-4'-benzyloxydiphenylsulfone, bis (4-hydroxy Phenyl) methyl acetate, bis (4-hydroxyphenyl) butyl acetate, bis (4-hydroxyphenyl) acetate benzyl, phenolic compounds such as 2,4-dihydroxy-2′-methoxybenzanilide, benzyl p-hydroxybenzoate, p-hydro 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, etc. An aromatic carboxylic acid derivative, an aromatic carboxylic acid or a polyvalent metal salt thereof can be used.

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

  Specific examples of waxes include, for example, wood wax, carnauba wax, shellac, paraffin, montan wax, oxidized paraffin, polyethylene wax, polyethylene oxide, etc .; higher fatty acids such as stearic acid, behenic acid, etc .; higher fatty acid amides For example, stearic acid amide, oleic acid amide, N-methyl stearic acid amide, erucic acid amide, methylol behenic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, etc .; Examples of naphthalene derivatives include 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, 2,6-diisopropylnaphthalene and the like; Examples of the group ether include 1,2-diphenoxyethane, 1,4-diphenoxybutane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methoxyphenoxy) ethane, 1, 2-bis (3,4-dimethylphenyl) ethane, 1-phenoxy-2- (4-chlorophenoxy) ethane, 1-phenoxy-2- (4-methoxyphenoxy) ethane, 1,2-diphenoxymethylbenzene, Diphenyl glycol and the like; examples of the aromatic carboxylic acid derivative include p-hydroxybenzoic acid benzyl ester, p-benzyloxybenzoic acid benzyl ester and terephthalic acid dibenzyl ester; and the aromatic sulfonic acid ester derivative such as p-toluene. Sulfonic acid phenyl ester, phenyl mesitylene sulfonate, 4- Examples of carbonic acid or oxalic acid diester derivatives include diphenyl carbonate, oxalic acid dibenzyl ester, oxalic acid di (4-chlorobenzyl) ester, oxalic acid di (4- Methyl benzyl) esters; biphenyl derivatives such as p-benzylbiphenyl and p-allyloxybiphenyl; terphenyl derivatives such as m-terphenyl and the like; sulfone derivatives such as p-toluenesulfonamide and benzene Sulfonanilide, p-toluenesulfonanilide, 4,4′-diallyloxydiphenylsulfone, diphenylsulfone and the like; Examples of aromatic ketone derivatives include 4,4′-dimethylbenzophenone and dibenzoylmethane; Examples of the group hydrocarbon compound include p-acetotoluidine.

  Specific examples of the storage stability improver used in the present invention include, for example, 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol). ), 2,2′-ethylidenebis (4,6-di-tert-butylphenol), 4,4′-thiobis (2-methyl-6-tert-butylphenol), 4,4′-butylidenebis (6-tert- Butyl-m-cresol), 1- [α-methyl-α- (4′-hydroxyphenyl) ethyl] -4- [α ′, α′-bis (4′-hydroxyphenyl) ethyl] benzene, 1,1 , 3-Tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert- Tilphenyl) butane, tris (2,6-dimethyl-4-tertiarybutyl-3-hydroxybenzyl) isocyanurate, 4,4′-thiobis (3-methylphenol), 4,4′-dihydroxy-3,3 ′ , 5,5′-tetrabromodiphenylsulfone, 4,4′-dihydroxy-3,3 ′, 5,5′-tetramethyldiphenylsulfone, 2,2-bis (4-hydroxy-3,5-dibromophenyl) Hindered phenol compounds such as propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,4-di Glycidyloxybenzene, 4,4′-diglycidyloxydiphenylsulfone, 4-benzyloxy-4 ′-(2-methylglyci (Zyloxy) diphenylsulfone, diglycidyl terephthalate, cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin, N, N′-di-2-naphthyl-p-phenylenediamine, 2,2 Examples include sodium or polyvalent metal salts of '-methylenebis (4,6-di-tert-butylphenyl) phosphate, bis (4-ethyleneiminocarbonylaminophenyl) methane, and the like. For example, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-ethylidenebis (4,6-di-) -Tert-butylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl-m-cresol), 1- [α-methyl-α -(4'-hydroxyphenyl) ethyl] -4- [α ', α'-bis (4'-hydroxyphenyl) ethyl] benzene, 1,1,3-tris (2-methyl-4-hydroxy-5- Cyclohexylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, tris (2,6-dimethyl) 4-tertiarybutyl-3-hydroxybenzyl) isocyanurate, 4,4′-thiobis (3-methylphenol), 4,4′-dihydroxy-3,3 ′, 5,5′-tetrabromodiphenylsulfone, 4 , 4′-dihydroxy-3,3 ′, 5,5′-tetramethyldiphenylsulfone, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-) Hindered phenol compounds such as 3,5-dichlorophenyl) propane and 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,4-diglycidyloxybenzene, 4,4′-diglycidyloxy Diphenyl sulfone, 4-benzyloxy-4 ′-(2-methylglycidyloxy) diphenyl sulfone, terephthalic acid digg Epoxy compounds such as lysidyl, cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A type epoxy resin, N, N′-di-2-naphthyl-p-phenylenediamine, 2,2′-methylenebis (4,6 -Di-tert-butylphenyl) phosphate sodium or polyvalent metal salt, bis (4-ethyleneiminocarbonylaminophenyl) methane, urea urethane compound (developed compound UU manufactured by Chemipro Kasei Co., Ltd.), and the following formula And a diphenylsulfone cross-linking compound represented by (11) or a mixture thereof.

（式中、ａは０〜６の整数である。）

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

  Specific examples of the binder used in the present invention include, for example, methyl cellulose, methoxy cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose, cellulose, polyvinyl alcohol (PVA), carboxyl 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 / anhydrous Water-soluble maleic acid copolymer such as alkali salt, (meth) acrylic acid ester copolymer, styrene / (meth) acrylic acid ester copolymer , Polyurethane, polyester polyurethane, polyether polyurethane, polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinylidene chloride, polystyrene, styrene / butadiene (SB) Polymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, acrylonitrile / butadiene (NB) copolymer, carboxylated acrylonitrile / butadiene (NB) copolymer, colloidal silica And hydrophobic polymer emulsions such as composite particles of (meth) acrylic resin.

  Specific examples of the filler used in the present invention include, for example, calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin. And urea-formalin resin.

  Furthermore, various additives other than those described 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 preventing thermal head wear and sticking, and preventing oxidation or aging. Examples thereof include ultraviolet absorbers such as phenol derivatives, benzophenone compounds, and benzotriazole compounds for imparting effects, various surfactants, and antifoaming agents.

Next, a method for preparing the heat-sensitive recording material of the present invention will be described. Dispersers such as a ball mill, an attritor, a sand mill, and the like, which are used in the present invention, separately from the color-forming compound, the imidazole compound, and the compound represented by the formula (1), together with a binder or other additives as required. To prepare a dispersion liquid (usually, water is used as a medium when pulverization or dispersion is performed in a wet manner), and then the dispersion liquid is mixed to prepare a thermal recording material coating liquid. High-quality paper, coated paper, etc.), a plastic sheet, a synthetic paper or the like is coated and dried by a bar coater, a blade coater or the like so that the dry weight is usually 1 to 20 g / m ^2. A sample having the heat-sensitive recording material is prepared.

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 crushed and dispersed as necessary in the same manner as in the preparation of the heat-sensitive recording material coating solution, for example, together with the binder or other additives as necessary. After forming a coating solution for a layer or a coating solution for an overcoat layer (protective layer), the thermal recording of the present invention is to apply the coating solution so that the weight during drying is usually about 0.1 to 10 g / m ² and to dry. A sample with material is made.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by the following examples. In the examples, “parts” are parts by weight, and “%” in the description of the solution is% by weight.

[Example 1] (Preparation of thermal recording material)
A mixture of the following composition was pulverized and dispersed using a sand grinder so that the median particle diameter was 1 μm or less to prepare an imidazole compound dispersion [A].

[A] Liquid: 25 parts of 2-phenylimidazole (Wako Pure Chemical Industries)
20 parts of 25% PVA aqueous solution
55 parts of water

  A mixture of the following composition was pulverized and dispersed using a sand grinder so that the median particle diameter was 1 μm or less to prepare a color developing compound dispersion [B].

[B] Liquid: 35 parts of 3-dibutylamino-6-methyl-7-anilinofluorane
40 parts of 15% PVA aqueous solution
25 parts of water

  A mixture of the following composition was pulverized and dispersed using a sand grinder so that the median particle diameter was 1 μm or less to prepare a dispersion [C] of Compound No. 1 described in Table 1 above.

[C] Solution: 25 parts of the compound number 1 described in Table 1
20 parts of 25% PVA aqueous solution
55 parts of water

Next, each dispersion liquid obtained above and the following chemicals were mixed at the following composition ratio to prepare a thermal recording material coating liquid, and the weight when dried on a fine paper having a basis weight of 50 g / m ² was 5 g / m. A sample having the heat-sensitive recording material of the present invention was prepared by coating and drying so as to be ² .
[A] Liquid 16.8 parts [B] Liquid 8.6 parts [C] Liquid 7.2 parts 67% calcium carbonate aqueous dispersion 9.0 parts 48% modified styrene / butadiene copolymer latex 6.3 parts Water 52.1 copies

(Formation of protective layer)
Next, a sample having the heat-sensitive recording material of the present invention with a protective layer was applied by applying a protective layer coating solution having the following composition onto the heat-sensitive recording layer so that the weight upon drying was 2 g / m ² and drying. Obtained.
40% styrene / acrylic ester copolymer emulsion 115 parts 5% bentonite aqueous dispersion 17 parts 45% styrene / acrylic copolymer aqueous emulsion 44 parts 39% zinc stearate aqueous dispersion 103 parts 67% calcium carbonate aqueous dispersion 15 copies

[Example 2]
A mixture having the following composition was pulverized and dispersed for 1 hour using a multi-bead shocker (model: PV1001 (S)) manufactured by Yasui Kikai Co., Ltd. to prepare a [D] solution.

[D] Liquid: 4-methyl-2-phenylimidazole (Tokyo Chemical Industry) 15 parts
20 parts of 25% PVA aqueous solution
65 parts of water

Next, the [D] solution was used instead of the [A] solution of Example 1, and the mixture of the following composition ratios was mixed to prepare a thermal recording material coating solution. A sample having a thermosensitive recording material was prepared.
[D] Liquid 28.0 parts [B] Liquid 8.6 parts [C] Liquid 7.2 parts 67% calcium carbonate aqueous dispersion 9.0 parts 48% Modified styrene / butadiene copolymer latex 6.3 parts Water 40.9 parts

[Example 3]
In the composition of [D] solution of Example 2, [E] solution was prepared using benzimidazole (Tokyo Chemical Industry) instead of 4-methyl-2-phenylimidazole, and [E] instead of [D] solution. A sample having the heat-sensitive recording material of Example 3 was produced in the same manner as in Example 2 except that the liquid was used.

[Example 4]
In the composition of the [D] liquid of Example 2, the [F] liquid was prepared using hydantoin (Tokyo Chemical Industry) instead of 4-methyl-2-phenylimidazole, and the [F] instead of the [D] liquid. A sample having the thermosensitive recording material of Example 4 was produced in the same manner as in Example 2 except that the liquid was used.

[Comparative Example 1]
A mixture [G] was prepared by pulverizing and dispersing a mixture having the following composition using a sand grinder so that the median particle diameter was 1 μm or less.

[G] Liquid: 25 parts of 1,3-diphenylurea (Tokyo Chemical Industry)
20 parts of 25% PVA aqueous solution
55 parts of water Sample of Comparative Example 1 in the same manner as in Example 1 except that [G] liquid was used instead of [C] liquid in the composition of the thermal recording material coating liquid described in Example 1 above. Got.

[Comparative Example 2]
A sample having the thermosensitive recording material of Comparative Example 2 was prepared in the same manner as in Example 2 except that the [G] liquid was used instead of the [C] liquid of Example 2.

[Comparative Example 3]
A sample having the thermosensitive recording material of Comparative Example 3 was prepared in the same manner as in Example 2 except that the [G] liquid was used instead of the [C] liquid of Example 3.

[Comparative Example 4]
A sample having the thermosensitive recording material of Comparative Example 4 was produced in the same manner as in Example 4 except that the [G] liquid was used instead of the [C] liquid of Example 4.

[Heat resistance of printed part]
Each sample obtained from Examples 1 to 4 and Comparative Examples 1 to 4 was printed at a printing voltage of 16.0 V and a pulse width of 1.2 msec using a thermal printer (TH-M2 / PP) manufactured by Okura Engineering Co., Ltd. And it was hold | maintained for 1 hour under 70 degreeC using the Yamato Scientific Co., Ltd. ventilation constant temperature thermostat, brand name DKN402. The Macbeth reflection density of the background before and after the test was measured using a colorimeter manufactured by GRETAG-MACBETH, trade name: SpectroEye. When measuring colors, all were performed 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 2 below. In addition, it turns out that it is excellent in heat resistance, so that a residual rate is high. The residual rate was calculated by the following formula.
Residual rate (%) = (Macbeth reflection density of printed part of sample after test) / (Macbeth reflection density of printed part of sample before test) × 100

上記の表２より明らかなように、イミダゾール系化合物と式（１）で示される化合物を併用した感熱記録材料を用いた実施例１乃至４は、イミダゾール系化合物を１，３−ジフェニル尿素と併用した特許文献３に記載の感熱記録材料を用いた比較例１に比べ、耐熱性に優れていることが分かる。

As is apparent from Table 2 above, Examples 1 to 4 using the thermosensitive recording material in which the imidazole compound and the compound represented by the formula (1) are used in combination use the imidazole compound in combination with 1,3-diphenylurea. It can be seen that the film is superior in heat resistance as compared with Comparative Example 1 using the thermosensitive recording material described in Patent Document 3.

Claims (7)

A heat-sensitive recording material comprising an imidazole compound and a compound represented by the following general formula (1).

(In formula (1), R ¹ represents an alkyl group.) 2. The heat-sensitive recording material according to claim 1, wherein in the general formula (1), R ¹ is an alkyl group which is unsubstituted or substituted with an aryl group. The heat-sensitive recording material according to claim 1 or 2, wherein in the general formula (1), R ¹ is an unsubstituted alkyl group. The thermosensitive recording material according to any one of claims 1 to 3, wherein in the general formula (1), R ¹ is a methyl group or an ethyl group. The heat-sensitive recording material according to any one of claims 1 to 4, wherein the imidazole compound is 2-phenylimidazole. A thermosensitive recording layer comprising the thermosensitive recording material according to any one of claims 1 to 5. A thermal recording paper comprising the thermal recording layer according to claim 6.