Fluorane dimer-based compounds and recording materials using the same

Abstract

The fluorane dimer compounds of the present invention are represented by the following general formula (1).

Description

Technical Field

[0001] This invention relates to fluorane dimer compounds and recording materials containing the same. More specifically, it relates to fluorane dimer compounds suitable for recording materials capable of reacting with an electron-accepting colorimetric agent using a photothermal conversion material heated by near-infrared light from a thermal head or laser, thereby recording magenta (true red) images or data. Background Technology

[0002] In recent years, from the perspective of global environmental protection, rewritable recording materials technology has made significant progress. As a reversible recording medium that can reversibly record or erase information through heat or light, it is driving the widespread adoption of various prepaid cards, loyalty cards, credit cards, IC cards, etc. In addition, research is underway to apply reversible recording media to the display field.

[0003] At the same time, from a design perspective, the trend is towards full-color production. In particular, there is a need for a colorant that can produce a vivid magenta (true red) from the three primary colors, and that exhibits excellent durability before and after color development.

[0004] For example, Patent Document 1 and Patent Document 2 disclose fluorane compounds with a magenta (true red) color.

[0005] However, when used as a colorant for full-color thermal recording materials, it exhibits low lightfastness before and after color development, and color changes may occur, thus requiring improvement.

[0006] On the other hand, fluorane dimer compounds are disclosed in Patent Documents 3, 4, 5, and Non-Patent Document 1. However, since their hues are not a bright magenta (true red), improvements are needed.

[0007] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 50-5117 Patent Document 2: Japanese Patent Application Publication No. 10-109477 Patent Document 3: US 4012419 Publication Patent Document 4: US 5618063 Publication Patent Document 5: Japanese Patent Application Publication No. 11-245523 Non-patent literature Non-patent literature 1: Journal of the Serbian Chemical Society (2003), 68(8-9), 607-613 Summary of the Invention

[0008] The problem that the invention aims to solve The subject of this invention is to provide a fluorane dimer compound that exhibits a bright magenta (true red) color, high lightfastness and other properties before and after color development, and inhibits degradation, as well as a recording material containing the compound.

[0009] Methods for solving problems The inventors of this application conducted research on the above-mentioned problem and found that the problem could be solved by including a fluorane dimer compound with a specific structure in the color-developing composition, thereby completing the present invention.

[0010] That is, the present invention is as follows.

[0011] [1] The following general formula (1) represents the fluorane dimer system compounds.

[0012] [Chemical Formula 1] In formula (1), R1 and R2 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted aryl group. R1 and R2 can bond with each other to form an aliphatic ring. R3 to R6 each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, and a substituted or unsubstituted arylthio group. R3 to R6 can bond with each other to form an aliphatic ring or an aromatic ring.

[0013] R7 represents a hydrogen atom or an unsubstituted alkyl group.

[0014] Q represents an unsubstituted benzene ring or an unsubstituted naphthalene ring. A is selected from substituted or unsubstituted aryl groups, or groups represented by the following general formula (2). n represents 0 or 1. [Chemical Formula 2] (In formula (2), Z represents an oxygen atom, a sulfur atom, a phenylene group, a ketone group, or a substituted or unsubstituted alkylene group, and R8 represents a hydrogen atom or an unsubstituted alkyl group. l and m each independently represent 0 or 1. Wherein, m represents 1 when l is 0, and l represents 1 when m is 0. It should be noted that (*) indicates the bonding position.) [2] Fluorane dimer compounds as described in [1], wherein Q is an unsubstituted benzene ring.

[0015] [3] The fluorane dimer system compounds as described in [1], wherein Q is an unsubstituted naphthalene ring.

[0016] [4] The fluorane dimer compound as described in any one of [1] to [3], wherein R1 and R2 are each independently hydrogen atoms, substituted or unsubstituted alkyl groups having 1 to 20 carbon atoms, substituted or unsubstituted aralkyl groups having 7 to 25 carbon atoms, or substituted or unsubstituted aryl groups having 6 to 24 carbon atoms, and R1 and R2 can be bonded to each other to form a heterocyclic aliphatic ring having 4 to 20 carbon atoms.

[0017] [5] The fluorane dimer compound as described in any one of [1] to [4], wherein R3 to R6 each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 25 carbon atoms, a substituted or unsubstituted alkyl thio group having 1 to 25 carbon atoms, or a substituted or unsubstituted aryl thio group having 6 to 25 carbon atoms, and R3 to R6 can be bonded to each other to form a substituted or unsubstituted carbocyclic aliphatic ring having 5 to 20 carbon atoms or a substituted or unsubstituted carbocyclic aromatic ring having 6 to 20 carbon atoms.

[0018] [6] A fluorane dimer compound as described in any one of [1] to [5], wherein R7 is a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms.

[0019] [7] A fluorane dimer compound as described in any one of [1] to [6], wherein A is a substituted or unsubstituted arylene group having 6 to 18 carbon atoms or a group represented by the aforementioned general formula (2). In the general formula (2), Z represents an oxygen atom, a sulfur atom, a ketone group, or a substituted or unsubstituted alkylene group with 1 to 20 carbon atoms, and R8 represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms.

[0020] [8] Recording material, which comprises an electron-donating chromophore and an electron-accepting chromophore, and utilizes their chromogenic reactions, wherein, The aforementioned electron-donating colorant includes at least one of the fluorane dimer systems described in any one of [1] to [7].

[0021] [9] A thermal recording material formed from the recording material described in [8].

[0022] Invention Effects The fluorane dimer compounds of the present invention react (interact) with a chromogenic agent to produce a vivid magenta (true red) color. Therefore, when the fluorane dimer compounds of the present invention are used as recording materials, they are colorless or substantially colorless before color development and provide a vivid magenta color image after color development. Furthermore, the recording material exhibits excellent storage stability before color development and high lightfastness of the image after color development, thus stably providing a vivid magenta color image. Therefore, the fluorane dimer compounds of the present invention can be suitably used as magenta (true red) chromogenic materials for full-color thermal recording materials. Detailed Implementation

[0023] The present invention will now be described in detail.

[0024] The fluorane dimer compounds of the present invention are included, at least one of them, as electron-donating chromophores in recording materials that utilize the chromogenic reaction of an electron-donating chromophore and an electron-accepting chromophore.

[0025] First, the following describes the fluorane dimer compounds.

[0026] [Fluorane dimer compounds] The fluorane dimer compounds of the present invention are represented by the following general formula (1).

[0027] [Chemical Formula 3] In formula (1), R1 and R2 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted aryl group. R1 and R2 can bond with each other to form an aliphatic ring.

[0028] R3 to R6 each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, or a substituted or unsubstituted arylthio group. R3 to R6 can bond with each other to form an aliphatic ring or an aromatic ring.

[0029] R7 represents a hydrogen atom or an unsubstituted alkyl group.

[0030] Q represents an unsubstituted benzene ring or an unsubstituted naphthalene ring.

[0031] A is selected from substituted or unsubstituted aryl groups, or groups represented by the following general formula (2). n represents 0 or 1.

[0032] [Chemical Formula 4] In formula (2), Z represents an oxygen atom, a sulfur atom, a phenylene group, a ketone group, or an alkylene group, and R8 represents a hydrogen atom or an unsubstituted alkyl group. l and m each independently represent 0 or 1. Wherein, m represents 1 when l is 0, and l represents 1 when m is 0. It should be noted that (*) indicates the bonding position.

[0033] In R1 and R2 shown in equation (1), Examples of substituted or unsubstituted alkyl groups include alkyl groups having 1 to 20 carbon atoms, preferably 1 to 12, and more preferably 1 to 8.

[0034] Examples of unsubstituted alkyl groups include, for instance, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 4-methylpentyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, cyclopentyl, cyclohexyl, 4-methylcyclohexyl, 3-methylcyclohexyl, 2-methylcyclohexyl, 4-ethylcyclohexyl, 4-isopropylcyclohexyl, 3,3,5-trimethylcyclohexyl, 4-butylcyclohexyl, 4-tert-butylcyclohexyl, 4-sec-butylcyclohexyl, 4-pentylcyclohexyl, and other straight-chain, branched, or cyclic unsubstituted alkyl groups.

[0035] Examples of substituted alkyl groups include, for instance: Alkyl groups having a straight-chain or cyclic alkyl group, such as methoxymethyl, ethoxymethyl, ethoxyethyl, (2-methoxyethoxy)ethyl, n-butoxymethyl, n-hexyloxymethyl, (2-ethylbutyloxy)methyl, 3-methoxypropyl, tetrahydrofuranylmethyl, etc. 2-(4'-pentenyloxy)ethyl and other alkyl groups having an alkenyloxy group; alkyl groups containing alkyl amino groups, such as 4-dimethylaminocyclohexyl. Alkyl groups containing aralkyloxy groups, such as benzyloxymethyl and 2-(benzyloxymethoxy)ethyl; Alkyl groups having aryloxy groups, such as phenyloxymethyl, 4-chlorophenyloxymethyl, and 4-(2'-phenyloxyethoxy)butyl; Alkyl groups containing alkyl thio groups, such as n-butylthiomethyl and 2-n-octylthioethyl. Alkyl groups containing halogen atoms, such as fluoromethyl, trifluoromethyl, perfluoroethyl, 2,2,3,3,3-pentafluoropropyl, 2,2,4,4,4-pentafluorobutyl, 4-fluorocyclohexyl, dichloromethyl, 4-chlorocyclohexyl, 7-chloroheptyl, 4-trifluoromethylcyclohexyl, and 3-trifluoromethylcyclohexyl.

[0036] Examples of substituted or unsubstituted aralkyl groups include those with 7 to 25 carbon atoms, preferably 7 to 20. Specifically, examples include: Benzyl, α-methylbenzyl, phenethyl, α-methylphenethyl, α,α-dimethylbenzyl, α,α-dimethylphenethyl, 4-methylphenethyl, 4-methylbenzyl, 4-isopropylbenzyl and other unsubstituted or alkyl aralkyl groups; 4-Benzylbenzyl, 4-phenylethylbenzyl, 4-phenylbenzyl, and other aralkyl groups containing aryl or aralkyl groups; Aryl groups with substituted oxygen groups, such as 4-methoxybenzyl, 4-tetradecyloxybenzyl, 4-heptadecyloxybenzyl, 3,4-dimethoxybenzyl, 4-methoxymethylbenzyl, 4-vinyloxymethylbenzyl, 4-benzyloxybenzyl, and 4-phenylethyloxybenzyl; Aryl groups containing halogen atoms, such as 4-fluorobenzyl, 3-chlorobenzyl, and 3,4-dichlorobenzyl; 2-Furfuryl, diphenylmethyl, 1-naphthylmethyl, 2-naphthylmethyl, etc.

[0037] Examples of aryl groups, whether substituted or unsubstituted, include those with 6 to 24 carbon atoms, preferably 6 to 19. In this specification, aryl means, for example, a carbocyclic aromatic group such as phenyl or naphthyl, or a heterocyclic aromatic group such as furanyl, thiophene, pyridyl, or pyrazinyl.

[0038] Examples of unsubstituted aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 2-anthrayl, 1-phenanthyl, 2-phenanthyl, 3-phenanthyl, 1-pyrene, 2-pyrene, 2-perylyl, 3-perylyl, 2-fluoranthryl, 3-fluoranthryl, 7-fluoranthryl, 8-fluoranthryl, 2-furanyl, 2-thienyl, 3-thienyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-methylpyrazinyl, 4-methylpyrazinyl, 5-methylpyrazinyl, etc.

[0039] Examples of aryl substitution include: 1-Methyl-2-pyrene, 2-methylphenyl, 4-methylphenyl, 4-ethylphenyl, 4-tert-butylphenyl, 4-(4'-tert-butylcyclohexyl)phenyl, 3-cyclohexylphenyl, 2-cyclohexylphenyl, 4-ethyl-1-naphthyl, 6-n-butyl-2-naphthyl, 2,4-dimethylphenyl, 5-ethyl-2-thienyl, 5-n-pentyl-2-thienyl, 5-n-decyl-2-thienyl, 2-methylpyrazinyl, 4-methylpyrazinyl, 5-methylpyrazinyl and other aryl groups having alkyl groups; 4-Methoxyphenyl, 3-ethoxyphenyl, 2-ethoxyphenyl, 4-n-propoxyphenyl, 3-n-propoxyphenyl, 4-isopropoxyphenyl, 3-isopropoxyphenyl, 2-isopropoxyphenyl, 2-sec-butoxyphenyl, 4-n-pentyloxyphenyl, 4-isopentyloxyphenyl, 2-methyl-5-methoxyphenyl, 2-phenyloxyphenyl, etc., aryl groups having alkoxy or aryloxy groups; 4-Phenylene, 3-Phenylene, 2-Phenylene, 2,6-Diphenylphenyl, 4-(2'-naphthyl)phenyl, 2-Pheny-1-naphthyl, 1-Pheny-2-naphthyl, 7-Pheny-1-pyrene, 5-Pheny-2-thienyl, 5-(2'-thienyl)-2-thienyl and other aryl groups containing aryl groups; 4-Fluorophenyl, 3-Fluorophenyl, 2-Fluorophenyl, 4-Chlorophenyl, 4-Bromophenyl, 2,4,6-Trichlorophenyl, 2-Chloro-5-Methylphenyl, 2-Chloro-6-Methylphenyl, 2-Methyl-3-Chlorophenyl, 2-Methoxy-4-Fluorophenyl, 2-Fluoro-4-Methoxyphenyl, 2-Fluoropyrazinyl, 4-Fluoropyrazinyl, 5-Fluoropyrazinyl and other aryl groups having halogen atoms; 2-Trifluoromethylphenyl, 3-Trifluoromethylphenyl, 4-Trifluoromethylphenyl, 3,5-Bis(trifluoromethyl)phenyl, 4-Perfluoroethylphenyl, 4-Methylthiophenyl, 4-Ethylthiophenyl, 4-Cyanophenyl, 3-Cyanophenyl, etc.

[0040] R1 and R2 can be linked together to form a ring. In the case of ring formation, the ring typically contains bonded nitrogen atoms. As a ring thus formed, substituted or unsubstituted heterocyclic aliphatic rings are preferred, and substituted or unsubstituted heterocyclic aliphatic rings with a total carbon number of 4 to 20 are more preferred.

[0041] Specific examples of heterocyclic aliphatic rings include pyrrolidine rings, piperazine rings, piperidine rings, morpholine rings, and thiomorpholine rings. The resulting heterocyclic aliphatic rings can also have multiple substituents.

[0042] Examples of substituents mentioned above include halogen atoms, carboxyl groups, cyano groups, nitro groups, hydroxyl groups, straight-chain, branched, or cyclic alkyl groups with 1 to 20 carbon atoms, straight-chain, branched, or cyclic alkoxy groups with 1 to 20 carbon atoms, or aryl groups that can be substituted with halogen atoms, carboxyl groups, cyano groups, nitro groups, hydroxyl groups, straight-chain, branched, or cyclic alkyl groups with 1 to 20 carbon atoms, or straight-chain, branched, or cyclic alkoxy groups with 1 to 20 carbon atoms.

[0043] From the viewpoint of the effects of the present invention, R1 and R2 shown in formula (1) are preferably each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 25 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 24 carbon atoms, or R1 and R2 are bonded together to form a substituted or unsubstituted heterocyclic aliphatic ring having 4 to 20 carbon atoms, more preferably a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.

[0044] In equation (1), among R3~R6, Examples of halogen atoms include chlorine, fluorine, bromine, and iodine, with chlorine and fluorine being the preferred choices.

[0045] As substituted or unsubstituted alkyl groups, specific examples of R1 and R2 mentioned above can be cited, and preferred specific examples are also the same.

[0046] Examples of substituted or unsubstituted alkoxy groups include alkoxy groups with 1 to 25 carbon atoms, preferably 1 to 15.

[0047] Examples of unsubstituted alkoxy groups include, for instance, methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, tert-butyloxy, sec-butyloxy, n-pentyloxy, isopentyloxy, n-hexyloxy, 2-methylpentyloxy, 1,1-dimethylbutyloxy, 1,2,2-trimethylpropyloxy, 2-ethylbutyloxy, 1,3-dimethylhexyloxy, cyclohexyloxy, methylcyclopentyloxy, n-heptyloxy, n-heptyloxy, n-octyloxy, 3,5,5-trimethylhexyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, 1-adamantyloxy, n-pentadecanyloxy, and other straight-chain, branched, or cyclic unsubstituted alkoxy groups.

[0048] Examples of substituted alkoxy groups include, for instance: Methoxymethoxy, ethoxymethoxy, n-propyloxymethoxy, n-butyloxymethoxy, isobutyloxymethoxy, tert-butyloxymethoxy, n-pentyloxymethoxy, 2-methoxyethoxy, 2-ethoxyethoxy, 2-n-propyloxyethoxy, 2-isopropyloxyethoxy, 2-n-butyloxyethoxy, 2-isobutyloxyethoxy, 2-tert-butyloxyethoxy, 2-sec-butyloxyethoxy, 2-n-pentyloxyethoxy, 2-isopentyloxyethoxy, 2-tert-pentyloxyethoxy, 2-sec-pentyloxyethoxy, 2-cyclopentyloxyethoxy, 2-n-hexyloxyethoxy Alkoxy groups containing alkoxy groups include 2-(4-ethylcyclohexyloxy)ethoxy, 2-n-nonyloxyethoxy, 2-(3,5,5-trimethylhexyloxy)ethoxy, 2-n-decyloxyethoxy, 2-n-dodecyloxyethoxy, 3-methoxypropyloxy, 3-ethoxypropyloxy, 3-(n-propyloxy)propyloxy, 2-isopentyloxypropyloxy, 2-methoxybutyloxy, 4-ethoxybutyloxy, 4-(n-propyloxy)butyloxy, 4-isopropyloxybutyloxy, 5-methoxypentyloxy, 5-ethoxymethoxy, and 6-n-propylhexyloxy. Methoxymethoxymethoxy, ethoxymethoxymethoxy, propoxymethoxymethoxy, butyloxymethoxymethoxy, methoxyethoxymethoxy, ethoxyethoxymethoxy, propoxyethoxymethoxy, methoxymethoxyethoxy, ethoxymethoxyethoxy, propoxymethoxyethoxy, butyloxymethoxyethoxy, propoxyethoxyethoxy, butyloxyethoxyethoxy, propoxyethoxyethoxy, butyloxyethoxyethoxy, propoxyethoxyethoxy, methoxymethoxypropyloxy, ethoxymethoxypropyloxy, butyloxymethoxypropyloxy, methoxymethoxybutyloxy, ethoxymethoxybutyloxy, butyloxymethoxybutyloxy, ethoxyethoxybutyloxy, (4-ethylcyclohexyloxy)ethoxyethoxy, [4-(3,5,5-trimethylhexyloxy)butyloxy]ethoxy, etc., alkoxy groups containing alkoxy or alkoxy groups.

[0049] Examples of substituted or unsubstituted aryloxy groups include aryloxy groups with 6 to 25 carbon atoms, preferably 6 to 18. Specifically, examples include phenyloxy, 2-methylphenyloxy, 4-methylphenyloxy, 4-ethylphenyloxy, 4-isopropylphenyloxy, 4-isobutylphenyloxy, 4-n-pentylphenyloxy, 4-tert-pentylphenyloxy, 4-cyclohexylphenyloxy, 4-n-octylphenyloxy, 4-n-decylphenyloxy, 4-n-dodecylphenyloxy, 4-n-hexadecylphenyloxy, 2,3-dimethylphenyloxy, and 2,5-dimethylphenyloxy. Oxygen, 3,4-dimethylphenyloxy, 3,4,5-trimethylphenyloxy, 5-indanyloxy, 1,2,3,4-tetrahydro-6-naphthyloxy, 3-methoxyphenyloxy, 3-ethoxyphenyloxy, 4-n-propoxyphenyloxy, 4-n-butoxyphenyloxy, 4-n-pentyloxyphenyloxy, 4-cyclohexyloxyphenyloxy, 4-n-octyloxyphenyloxy, 4-n-decyloxyphenyloxy, 4-n-dodecyloxyphenyloxy, 4-n-hexadecyloxyphenyloxy, 2,3-dimethoxyphenyloxy, 2,5-dimethoxyphenyloxy 3,5-Dimethoxyphenyloxy, 2-Methoxy-4-methylphenyloxy, 3-Methoxy-4-methylphenyloxy, 3-Methyl-4-methoxyphenyloxy, 2-Fluorophenyloxy, 4-Fluorophenyloxy, 3-Chlorophenyloxy, 4-Bromophenyloxy, 3-Trifluoromethylphenyloxy, 3,5-Difluorophenyloxy, 3,4-Dichlorophenyloxy, 2-Methyl-4-chlorophenyloxy, 3-Chloro-4-methylphenyloxy, 3-Methoxy-4-fluorophenyloxy, 3-Fluoro-4-methoxyphenyloxy, 4-Phenylephenyloxy, 3-Phenylephenyloxy, 4- (4'-Methylphenyl)phenyloxy, 4-(4'-methoxyphenyl)phenyloxy, 1-naphthyloxy, 4-methyl-1-naphthyloxy, 6-n-butyl-2-naphthyloxy, 7-ethoxy-2-naphthyloxy, 2-thienyloxy, 2-pyridyloxy, 4-pyridyloxy, 2-furanyloxy, 5-ethyl-2-thienyloxy, 5-n-pentyl-2-thienyloxy, 5-n-decyl-2-thienyloxy, 5-phenyl-2-thienyloxy, 5-(2'-thienyl)-2-thienyloxy, 3-thienyloxy, 3-pyridyloxy, etc.

[0050] Examples of substituted or unsubstituted alkyl thio groups include alkyl thio groups with 1 to 25 carbon atoms, preferably 1 to 15.

[0051] Examples of unsubstituted alkyl thio groups include methyl thio, ethyl thio, n-propyl thio, isopropyl thio, n-butyl thio, isobutyl thio, tert-butyl thio, sec-butyl thio, n-pentyl thio, isopentyl thio, n-hexyl thio, 2-methylpentyl thio, 1,1-dimethylbutyl thio, 1,2,2-trimethylpropyl thio, 2-ethylbutyl thio, 1,3-dimethylhexyl thio, cyclohexyl thio, methylcyclopentyl thio, n-heptyl thio, n-heptyl thio, n-octyl thio, 3,5,5-trimethylhexyl thio, n-decyl thio, n-undecyl thio, n-dodecyl thio, 1-adamantyl thio, n-pentadecanyl thio, and other straight-chain, branched, or cyclic unsubstituted alkyl thio groups.

[0052] Examples of substituted alkyl thio groups include: Methoxymethyl thio, ethoxymethyl thio, n-propyloxymethyl thio, n-butyloxymethyl thio, isobutyloxymethyl thio, tert-butyloxymethyl thio, n-pentyloxymethyl thio, 2-methoxyethyl thio, 2-ethoxyethyl thio, 2-n-propyloxyethyl thio, 2-isopropyloxyethyl thio, 2-n-butyloxyethyl thio, 2-isobutyloxyethyl thio, 2-tert-butyloxyethyl thio, 2-sec-butyloxyethyl thio, 2-n-pentyloxyethyl thio, 2-isopentyloxyethyl thio, 2-sec-pentyloxyethyl thio, 2-hexyloxyethyl Alkyl thiols containing alkoxy groups include thiols, 2-(4-ethylcyclohexyloxy)ethylthiols, 2-n-nonyloxyethylthiols, 2-(3,5,5-trimethylhexyloxy)ethylthiols, 2-n-decyloxyethylthiols, 2-n-dodecyloxyethylthiols, 3-methoxypropylthiols, 3-ethoxypropylthiols, 3-(n-propylthio)propylthiols, 2-isopentyloxypropylthiols, 2-methoxybutylthiols, 4-ethoxybutylthiols, 4-(n-propyloxy)butylthiols, 5-methoxypentylthiols, 5-ethoxypentylthiols, and 6-n-propyloxyhexylthiols. Methoxymethoxymethylthio, ethoxymethoxymethylthio, propyloxymethoxymethylthio, butyloxymethoxymethylthio, ethoxyethoxymethylthio, propyloxyethoxymethylthio, methoxymethoxyethylthio, ethoxymethoxyethylthio, propyloxymethoxyethylthio, butyloxymethoxyethylthio, propyloxyethoxyethylthio, butyloxyethoxyethylthio, propyloxybutyloxyethylthio, methoxymethoxypropylthio, ethoxymethoxypropylthio, butyloxymethoxypropylthio, butyloxymethoxybutylthio, ethoxyethoxybutylthio, cyclohexyloxyethoxyethylthio, [4-(3,5,5-trimethylhexyloxy)butyloxy]ethylthio, and other alkylthio groups having alkoxyalkoxy groups; Alkyl thio groups containing an alkoxycarbonyl group include methoxycarbonylmethylthio, ethoxycarbonylmethylthio, n-propyloxycarbonylmethylthio, methoxycarbonylethylthio, ethoxycarbonylethylthio, n-propyloxycarbonylethylthio, and ethoxycarbonylpropylthio. Alkyl thiols containing alkyl amino groups include methylaminomethylthiol, 2-methylaminoethylthiol, 2-(2-methylaminoethoxy)ethylthiol, 4-methylaminobutylthiol, 1-methylaminopropane-2-yloxy, 3-methylaminopropylthiol, 2-ethylaminoethylthiol, 2-(2-ethylaminoethoxy)ethylthiol, 3-ethylaminopropylthiol, 1-ethylaminopropylthiol, 2-isopropylaminoethylthiol, 2-(n-butylamino)ethylthiol, 3-(n-hexylamino)propylthiol, and 4-(cyclohexylamino)butylthiol. Alkyl thio groups containing dialkylamino groups include dimethylaminomethylthio, 2-dimethylaminoethylthio, 4-dimethylaminobutylthio, 1-dimethylaminopropane-2-ylthio, 3-dimethylaminopropylthio, 2-diethylaminoethylthio, 3-diethylaminopropylthio, 2-diisopropylaminoethylthio, 2-(di-n-butylamino)ethylthio, 2-piperidinylethylthio, and 3-(di-n-hexylamino)propylthio. Alkyl thiols, such as methyl thiols, 2-methyl thioethyl thiols, 2-ethyl thioethyl thiols, 2-n-propyl thioethyl thiols, 2-isopropyl thioethyl thiols, 2-n-butyl thioethyl thiols, 2-isobutyl thioethyl thiols, and (3,5,5-trimethylhexyl thio)hexyl thiols, contain alkyl thio groups. Alkyl thio groups containing heterocyclic groups include 2-N-morpholinyl ethyl thio, 2-N-pyridyl ethyl thio, 2-N-pyrrolithyl ethyl thio, 2-(2-furanyl)ethyl thio, 2-(1-indolyl)ethyl thio, 2-(3-thienyl)ethyl thio, 3-N-morpholinyl propyl thio, 3-N-pyridyl propyl thio, 3-N-pyrrolithyl propyl thio, and 3-(1-indolyl)propyl thio. Alkyl thiols containing aryl groups include phenylmethyl thiols, methylphenylmethyl thiols, ethylphenylmethyl thiols, tert-butylphenylmethyl thiols, phenylethyl thiols, methylphenylethyl thiols, ethylphenylethyl thiols, tert-butylphenylethyl thiols, etc.

[0053] Examples of arylthio groups, whether substituted or unsubstituted, include those with 6 to 25 carbon atoms, preferably 6 to 18. Specifically, examples include phenylthio, 2-methylphenylthio, 4-methylphenylthio, 3-ethylphenylthio, 4-n-propylphenylthio, 4-isopropylphenylthio, 4-n-butylphenylthio, 4-isobutylphenylthio, 4-tert-butylphenylthio, 4-n-pentylphenylthio, 4-n-hexylphenylthio, 4-cyclohexylphenylthio, and 4-n-octylphenylthio. 2,4-dimethylphenylthio, 4-dodecylphenylthio, 4-octadecylphenylthio, 2,4-dimethylphenylthio, 2,5-dimethylphenylthio, 3,4-dimethylphenylthio, 2,4,6-trimethylphenylthio, 5-indanylthio, 1,2,3,4-tetrahydro-6-naphthylthio, 2-methoxyphenylthio, 3-methoxyphenylthio, 4-methoxyphenylthio, 4-ethoxyphenylthio, 4-propoxyphenylthio, 2,4-dimethoxyphenyl 2-methyl-4-methoxyphenylthio, 3,5-diethoxyphenylthio, 2-methoxy-4-methylphenylthio, 2-methyl-4-methoxyphenylthio, 2-fluorophenylthio, 4-fluorophenylthio, 2-chlorophenylthio, 4-chlorophenylthio, 4-bromophenylthio, 4-trifluoromethylphenylthio, 3-trifluoromethylphenylthio, 2,4-difluorophenylthio, 2,4-dichlorophenylthio, 2,4,6-trifluorophenylthio, 2,4,6-trichlorophenylthio, 2-chloro-4-methoxy Phenylthio, 2-naphthylthio, 4-methyl-1-naphthylthio, 4-ethoxy-1-naphthylthio, 2-pyridylthio, 4-aminophenylthio, 4-(N,N-dimethylamino)phenylthio, 4-(N,N-diethylamino)-1-naphthylthio, 4-[N,N-di(4'-methylphenyl)amino]phenylthio, 4-(N-phenoxazinyl)phenylthio, 4-hydroxyphenylthio, 2,4-dihydroxyphenylthio, 4-methylthiophenylthio, etc.

[0054] R3 to R6 can be linked together to form a ring. When a ring is formed, typically adjacent R3 and R4, R4 and R5, and R5 and R6 are linked, each containing a bonded carbon atom to form a ring. Examples of such rings include substituted or unsubstituted carbocyclic aliphatic rings, substituted or unsubstituted carbocyclic aromatic rings, substituted or unsubstituted heterocyclic aliphatic rings, or substituted or unsubstituted heterocyclic aromatic rings. More preferably are substituted or unsubstituted carbocyclic aliphatic rings with a total carbon number of 5 to 20, substituted or unsubstituted carbocyclic aromatic rings with a total carbon number of 6 to 20, substituted or unsubstituted heterocyclic aliphatic rings with a total carbon number of 4 to 20, or substituted or unsubstituted heterocyclic aromatic rings with a total carbon number of 4 to 20.

[0055] As a specific example of a carbocyclic aliphatic ring. Examples include cyclopentane rings, cyclohexane rings, cyclohexene rings, cycloheptane rings, cyclooctane rings, and cyclodecane rings.

[0056] As a specific example of a carbocyclic aromatic ring. For example, benzene rings and naphthalene rings can be cited.

[0057] As a specific example of a heterocyclic aliphatic ring. Examples include dihydrofuran ring, tetrahydrofuran ring, dihydrothiophene ring, dioxane ring, and dithiohexane ring.

[0058] As a specific example of a heterocyclic aromatic ring. Examples include furan rings, thiophene rings, benzofuran rings, benzothiophene rings, and pyrrole rings. It should be noted that the resulting carbocyclic aliphatic rings, carbocyclic aromatic rings, heterocyclic aliphatic rings, and heterocyclic aromatic rings can also have multiple substituents.

[0059] Examples of substituents mentioned above include halogen atoms, carboxyl groups, cyano groups, nitro groups, hydroxyl groups, straight-chain, branched, or cyclic alkyl groups with 1 to 20 carbon atoms, straight-chain, branched, or cyclic alkoxy groups with 1 to 20 carbon atoms, or aryl groups that can be substituted with halogen atoms, carboxyl groups, cyano groups, nitro groups, hydroxyl groups, straight-chain, branched, or cyclic alkyl groups with 1 to 20 carbon atoms, or straight-chain, branched, or cyclic alkoxy groups with 1 to 20 carbon atoms.

[0060] From the viewpoint of the effectiveness of the present invention, R3 to R6 shown in formula (1) are preferably each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 25 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 25 carbon atoms, a substituted or unsubstituted arylthio group having 6 to 25 carbon atoms, or R3 to R6 bonded together to form a substituted or unsubstituted carbocyclic aliphatic ring having 5 to 20 carbon atoms, or a substituted or unsubstituted carbocyclic aromatic ring having 6 to 20 carbon atoms. More preferably, it is a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 25 carbon atoms.

[0061] In the equation (1), R7, Examples of unsubstituted alkyl groups include, for instance, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, sec-pentyl, tert-pentyl, n-hexyl, 1-methylpentyl, 4-methylpentyl, 2-ethylbutyl, n-heptyl, 1-methylhexyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, etc.

[0062] From the viewpoint of the effects of the present invention, R7 in formula (1) is preferably an alkyl group with 1 to 12 hydrogen atoms and carbon atoms, and more preferably an unsubstituted alkyl group with 1 to 8 hydrogen atoms and carbon atoms.

[0063] In Equation (1), Q represents an unsubstituted benzene ring or an unsubstituted naphthalene ring.

[0064] In A shown in formula (1), the unsubstituted arylene group specifically refers to the divalent group generated by removing one hydrogen atom from each of the two different carbon atoms constituting the aromatic ring. Depending on the position of the removed carbon atom, examples include 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,4-naphthylene, 1,5-naphthylene, 2,7-naphthylene, 4,4'-biphenylene, 4,4'-terphenylene, etc.

[0065] In the case of arylene groups having substituents, straight-chain, branched, or cyclic alkyl groups are preferred as substituents. Specific examples of arylene groups having alkyl groups include, for example, 1,2,3,4-tetrahydro-5,8-naphthylene, 5-methyl-1,3-phenylene, 2,3-dicyclohexyl-1,4-phenylene, 4-tert-butyl-1,3-phenylene, etc.

[0066] From the viewpoint of the effect of the present invention, in A shown in formula (1), the substituted or unsubstituted arylene group is preferably a substituted or unsubstituted arylene group with 6 to 18 carbon atoms, and more preferably a substituted or unsubstituted arylene group with 6 to 14 carbon atoms.

[0067] In the group represented by the aforementioned general formula (2), Z represents an oxygen atom, a sulfur atom, a phenylene group, a ketone group, or a substituted or unsubstituted alkylene group.

[0068] As previously mentioned, phenylene is a divalent group generated by removing one hydrogen atom from each of the two different carbon atoms constituting the benzene ring. 1,4-phenylene is a preferred example.

[0069] In this invention, a ketone group refers to a group represented by [-(C=O)-] (without bonds to hydrogen atoms at both ends).

[0070] An alkylene group is a divalent group formed by removing one hydrogen atom from each of the two different carbon atoms constituting a substituted or unsubstituted alkyl group. Examples of alkylene groups with 1 to 20 carbon atoms, and more preferably 1 to 15 carbon atoms, are preferred.

[0071] It should be noted that, as substituted or unsubstituted alkyl groups, specific examples of R1 and R2 mentioned above can be given.

[0072] Examples of unsubstituted alkylene groups formed from unsubstituted alkyl groups include: Alkyl groups such as methylene [-CH2-], ethylene [-CH2-CH2-], n-propylene [-CH2-CH2-CH2-], and n-butylene [-CH2-CH2-CH2-CH2-] are straight-chain alkylene groups composed only of carbon and hydrogen atoms; 1,2-Dimethyl ethylidene [-CH(CH3)-CH(CH3)-], ethylidene [-CH(CH3)-], isopropylidene [-C(CH3)2-], and other branched alkylene groups consisting only of carbon and hydrogen atoms.

[0073] Examples of substituted alkylene groups formed from substituted alkyl groups include: Branched substituted alkylene groups with halogen atoms, such as di(trifluoromethyl)methylene [-C(CF3)2-]: Monocyclic or bridged alicyclic alkylene compounds such as 1,3-cyclopentane, 1,4-cyclohexane, 1,2-cyclohexane, 2,3-bicyclo[2.2.1]heptane, 2,5-bicyclo[2.2.1]heptane, 2,6-bicyclo[2.2.1]heptane, 2,6-bicyclo[2.2.2]octane, and 1,3-adamantane-alkylene.

[0074] In R8, as an unsubstituted alkyl group, specific examples of the straight-chain unsubstituted alkyl groups described above in R1 and R2 can be given, preferably alkyl groups having 1 to 4 carbon atoms.

[0075] l and m each independently represent 0 or 1. When l is 0, m represents 1, and when m is 0, l represents 1.

[0076] From the viewpoint of the effectiveness of the present invention, A shown in formula (1) is preferably a substituted or unsubstituted arylene group with 6 to 18 carbon atoms or a group represented by the aforementioned general formula (2) (where Z represents an oxygen atom, a sulfur atom, a ketone group, a substituted or unsubstituted alkylene group with 1 to 20 carbon atoms, and R8 represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms). More preferably, it is a substituted or unsubstituted aryl group having 6 to 14 carbon atoms.

[0077] It should be noted that n in formula (1) represents 0 or 1. When n is 0, it indicates that the fluorane dimer compound is formed directly without the involvement of A. In this invention, n is particularly preferably 0.

[0078] Preferred embodiments of the fluorane dimer compounds of the present invention are shown in general formulas (1-1) to (1-10), but the present invention is not limited thereto.

[0079] [Chemical Formula 5] [Chemical Formula 6] [Chemical Formula 7] The examples of R1~R7, A and n in general formulas (1-1) to (1-10) have the same meaning as those in general formula (1), and their preferred methods are also the same.

[0080] Hereinafter, as specific examples of fluorane dimer compounds represented by general formula (1), the following compounds may be cited, but the present invention is not limited to these.

[0081] It should be noted that in the table, "―" in A indicates that when n in general formulas (1-1) to (1-10) is 0, the compounds are directly bonded and formed as fluorane dimers without the involvement of A.

[0082] [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7] [Table 8] [Table 9] [Preparation method of fluorane dimer compounds] The fluorane dimer compounds represented by general formula (1) can be manufactured by known methods. For example, they can be manufactured according to the method described in Japanese Patent Application Publication No. 5-70701.

[0083] In this embodiment, the method for producing fluorane dimer compounds of general formula (1-3) will be described using the following reaction formulas as examples.

[0084] In this method, it can be manufactured by reacting a keto acid derivative represented by formula (3) and a dimethoxybinaphthyl derivative represented by formula (4) at a temperature of 0-100°C for tens of hours in the presence of a dehydrating condensing agent, followed by alkali treatment. The keto acid derivative represented by formula (3) can be manufactured by, for example, the method described in Japanese Patent Application Publication No. 9-20734, and the dimethoxybinaphthyl derivative represented by formula (4) can be manufactured by, for example, the reaction of an organoboron compound and an organohalogen compound in the presence of a palladium catalyst as described in Japanese Patent Application Publication No. 2023-182866.

[0085] [Chemical Formula 8] In equations (3) and (1-3), R1~R7 have the same meaning as R1~R7 in general equation (1). In equations (4) and (1-3), A and n have the same meaning as A and n in general equation (1).

[0086] The reaction between the keto acid derivative represented by formula (3) and the naphthyl derivative having a naphthalene ring of formula (4) can be carried out under atmospheric conditions. As a dehydrating condensing agent, concentrated sulfuric acid, fuming sulfuric acid, polyphosphoric acid, and phosphorus pentoxide can be used, with concentrated sulfuric acid being particularly preferred. When concentrated sulfuric acid is used as the dehydrating condensing agent, the reaction temperature is preferably in the range of 0 to 180°C, and sometimes preferably 0 to 120°C.

[0087] The treatment based on alkali refers to the reaction of the keto acid derivative represented by formula (3) and the binaphthyl derivative of formula (4) in the presence of a dehydrating condensing agent, followed by exposure to alkali conditions at a certain temperature for a certain period of time. Sodium hydroxide, potassium hydroxide, sodium carbonate, etc., can be used as the alkali, with sodium hydroxide being particularly preferred, and preferably used in the form of an aqueous solution.

[0088] The treatment temperature is 0–100°C, preferably 50–100°C; generally, higher temperatures result in more efficient treatment. The amount of alkali used is preferably such that the treated solution has a pH of 9 or higher. The reactants treated with alkali are purified by extraction with an organic solvent.

[0089] Alternatively, organic solvents can be coexisted during alkaline treatment. Benzene, toluene, xylene, chlorobenzene, etc., can be used as organic solvents, with toluene generally preferred. When using organic solvents to precipitate the target product, methanol, ethanol, n-propanol, and isopropanol can also be used in conjunction.

[0090] Fluorane dimer compounds of general formula (1) thus manufactured may sometimes form solvates with solvents (e.g., alcohol solvents such as methanol and isopropanol, ketone solvents such as acetone and methyl ethyl ketone, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene), and the fluorane dimer compounds of general formula (1) of the present invention contain such solvates.

[0091] In addition, the fluorane dimer compounds represented by general formula (1) sometimes have multiple crystal forms (crystal variants) in their crystalline state, and the fluorane dimer compounds represented by general formula (1) of the present invention also contain such crystal variants.

[0092] [Recorded Materials] This invention relates to a recording material that produces a magenta (true red) color through a color-gathering reaction between an electron-donating chromophore and an electron-accepting chromophore. The electron-donating chromophore contains at least one compound selected from the fluorane dimer system represented by general formula (1). It should be noted that the preferred recording material is a pressure-sensitive recording material or a thermosensitive recording material, more preferably a thermosensitive recording material.

[0093] Furthermore, the present invention is a reversible thermal recording material, characterized in that, in the reversible recording material utilizing the color-changing reaction of an electron-donating chromophore and a color-changing agent, the electron-donating chromophore contains at least one of the fluorane dimer compounds represented by general formula (1).

[0094] In the recording material of the present invention, at least one of the fluorane dimer compounds represented by general formula (1) is used as a chromophore, but it may also be used in combination with other chromophores as desired, to the extent that the magenta (true red) is not impaired. As such other chromophores, various known chromophores used in the recording material may be used appropriately.

[0095] As a recording method, either a thermal imager or a laser imager can be used to record the color image onto the recording material of this invention.

[0096] Thermistors can be selected appropriately based on their application, without restrictions on their shape, structure, or size. Lasers, such as semiconductor lasers, YAG lasers, and fiber lasers with wavelengths in the near-infrared region, can be selected without limitation depending on the purpose.

[0097] The reason why the chromatic images of the recording material containing the fluorane dimer compound of the present invention have excellent lightfastness is generally believed to be that the pigment becomes excited by light and then becomes activated to undergo a light fading reaction. By rapidly deactivating the excited state to the ground state, the durability is improved.

[0098] The fluorane dimer compounds of the present invention have a structure in which two fluorane derivatives are linked together. Therefore, it can be considered that the pigment molecules will form pigment particles, i.e., an associated state, thereby promoting relaxation to the ground state.

[0099] Furthermore, by linking two fluorane derivatives, the solubility in oils and plasticizers is reduced compared to ordinary fluorane compounds, resulting in superior oil resistance and plasticizer resistance of the colored images.

[0100] [Thermal Recording Materials] The thermal recording material of this invention can be manufactured without relying on any special method, and can be manufactured according to known methods. For example, it can be manufactured using various known methods disclosed in Japanese Patent Publication No. 45-14039, etc.

[0101] Generally, in the presence of water, the fluorane dimer compound of the present invention, the color developer, and the desired hot-melt compound (sensitizer), etc., are mixed or separately using a ball mill, sand mill (vertical or horizontal), grinder, colloid mill, or other mixing or pulverizing mill, typically pulverized and dispersed to a particle size of 3 μm or less, preferably 2 μm or less, and then mixed to prepare a coating liquid for a thermal recording layer. Alternatively, depending on the circumstances, a eutectic with the fluorane dimer compound or color developer of the present invention may be prepared in advance and dispersed to prepare the coating liquid for a thermal recording layer.

[0102] Generally, the preparation of this coating is carried out in the presence of a binder. It should be noted that the binder is prepared in a manner that makes up approximately 5 to 50% by weight of the total solid components.

[0103] As adhesives, both water-soluble and water-insoluble polymers can be used. Preferred specific examples of water-soluble polymers include methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, starches, hydrolysates of styrene-maleic anhydride copolymers, hydrolysates of isobutylene-maleic anhydride copolymers, polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, and polyacrylamide. Examples of water-insoluble polymers include styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex, and vinyl acetate latex, but these are not limited to these.

[0104] In addition, pigments, metallic soaps, waxes, surfactants, antioxidants, UV absorbers, UV stabilizers, defoamers, etc., can be added to the coating solution as needed.

[0105] As pigments, both organic and inorganic pigments can be used. Preferred examples include inorganic pigments such as calcium carbonate, barium carbonate, magnesium carbonate, zinc carbonate, zinc oxide, aluminum oxide, and titanium oxide, and organic pigments such as styrene microspheres, nylon particles, urea-formaldehyde fillers, polyethylene particles, cellulose fillers, and starch particles.

[0106] As a metallic soap, higher fatty acid metal salts can be used. Preferred specific examples include zinc stearate, calcium stearate, and aluminum stearate.

[0107] Examples of waxes include paraffin wax, carboxyl-modified paraffin wax, and polyethylene wax.

[0108] Examples of surfactants (dispersants) include, for example, alkali metal salts of sulfosuccinic acid (e.g., sodium salts of di(n-hexyl)sulfosuccinic acid, di(2-ethylhexyl)sulfosuccinic acid, etc.), sodium salts of dodecylbenzenesulfonic acid, sodium salts of lauryl sulfate, fatty acid metal salts, and fluorinated surfactants.

[0109] Hindered phenols can be used as antioxidants.

[0110] Examples of UV absorbers and UV stabilizers include, for example, cinnamic acid derivatives, benzophenone derivatives, triazole derivatives, salicylic acid derivatives, hindered amine derivatives, etc.

[0111] The method for forming the thermal recording layer in the thermal recording material of the present invention is not particularly limited, and can be formed according to known techniques. For example, a suitable coating device such as an air knife coating machine, a doctor blade coating machine, a bar coating machine, a short-dwell coater, a gravure coating machine, a curtain coating machine, or a Mayer bar can be used to coat the thermal recording layer with a coating liquid onto a support, and then dry it to form the recording layer.

[0112] There is no specific limit to the coating amount; generally, it is 1.5~12 g / m² based on dry weight. 2 Left and right, preferably 2.5~10g / m 2 Prepared from left to right.

[0113] There are no particular limitations on the support material; for example, paper, plastic sheets, synthetic paper, or composite sheets made by combining them, non-woven sheets, as well as molded materials and metal vapor deposits can be used.

[0114] As needed, a protective layer (outer coating) can be provided on the surface and / or back of the thermal recording layer, or a single or multiple base coating (primer) formed of pigments (e.g., kaolin, calcium carbonate) or synthetic resins (e.g., plastic spherical particles, plastic hollow spherical particles) can be provided between the support and the thermal recording layer.

[0115] Alternatively, an intermediate layer made of pigments, adhesives, etc., can be provided between the thermal recording layer and the base layer, or between the thermal recording layer and the protective layer. Furthermore, various known techniques in the manufacturing methods of thermal recording materials, such as bonding the back of the support and processing it into an adhesive label, can be used.

[0116] It should be noted that, when using laser-based image recording methods, a photothermal conversion layer is preferably provided.

[0117] The photothermal conversion layer contains at least a pigment or dye that efficiently absorbs laser light with wavelengths in the near-infrared region and has a heating effect and absorbs light in the near-infrared region (hereinafter referred to as photothermal conversion material). There are no particular limitations on the formation method; it can be formed according to known techniques and can be used in conjunction with an adhesive resin.

[0118] The photothermal conversion material may be contained in at least one layer on the surface and / or back side of the thermal recording layer. When the thermal recording layer contains the photothermal conversion material, the thermal recording layer also serves as the photothermal conversion layer.

[0119] In addition, a barrier layer is sometimes formed to suppress the interaction between the constituent materials of the two layers between the thermal recording layer and the photothermal conversion layer. Preferably, this barrier layer contains a resin that can be cured by heat, ultraviolet light, electron beams, etc. It should be noted that the layer sandwiched between the thermal recording layer and the photothermal conversion layer is not particularly limited and can be appropriately selected depending on the purpose.

[0120] Examples of photothermal conversion materials include cyanine pigments, ketone acid pigments, polymethystylene pigments, azulenium pigments, squaric acid pigments, thiopyranium pigments, naphthoquinone pigments, anthraquinone pigments, phthalocyanine pigments, naphthalene phthalocyanine pigments, azo pigments, thioamide pigments, dithiol pigments, and indigoaniline pigments.

[0121] Various phenolic compounds can be used as color developers in thermal recording materials. Specific examples include bisphenol A, 2,2-bis(p-hydroxyphenyl)-4-methylpentane, 1,1-bis(p-hydroxyphenyl)cyclohexane, bisphenol S, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 3,3-diallyl-4,4'-dihydroxydiphenyl sulfone, 1,5-bis(p-hydroxyphenyl mercapto)-3-oxapentane, benzyl p-hydroxybenzoate, tetrabromobisphenol A, and tetrabromobisphenol S, with bisphenol A being particularly preferred.

[0122] Examples of sensitizers used in thermal recording materials include p-benzylbiphenyl, m-terphenyl, 2-benzyloxynaphthalene, 1,4-dibenzyloxynaphthalene, benzyl oxalate, di-p-methyl benzyl oxalate, di-p-chlorobenzyl oxalate, 1,2-diphenoxyethane, 1,2-m-tolyloxyethane, 1,2-di-p-tolyloxyethane, 1,4-diphenoxyethane, benzyl p-benzyloxybenzoate, phenyl 1-hydroxy-2-naphthoic acid, and benzyl terephthalate. P-benzylbiphenyl, m-terphenyl, 2-benzyloxynaphthalene, di-p-methyl benzyl oxalate, and 1,2-m-tolyloxyethane are particularly preferred.

[0123] [Reversible thermal recording materials] The reversible thermal recording material of the present invention can be manufactured using known methods without relying on any special method.

[0124] Generally, as a color-developing agent, the fluorane dimer compound, the color-reducing agent, or the long-chain color-developing agent of the present invention are dispersed together with a binder using a sand mill or the like to prepare a dispersion.

[0125] These dispersions are mixed, and as needed, alkaline compounds for decolorization at lower temperatures, thickeners as liquid modifiers, white pigments, etc., are added. The resulting recording coating is then applied to a support such as paper, plastic film, or sheet and dried.

[0126] In addition, protective layers, UV protection layers, and abrasion-resistant protection layers can be applied to the recording layer as needed to improve thermal head compatibility or to enhance the durability of the recording layer.

[0127] When using a color-reducing agent, the following principle is utilized: by controlling the heat energy, when the lactone ring of the fluorescent dimer compound of the present invention comes into contact with a color-producing group, the lactone ring cracks and produces color; when it comes into contact with a color-reducing group, the lactone ring closes and decolorizes.

[0128] When using a long-chain color developer, when heated above the melting point of the color developer, it melts and comes into contact with the fluorane dimer compound of the present invention to produce color. When slowly cooled from this state, the fluorane dimer compound of the present invention separates from the color developer and crystallizes, thus decolorizing.

[0129] On the other hand, upon rapid cooling, the color developer condenses regularly while maintaining its bond with the fluorane dimer compound of the present invention, thus maintaining the color development state.

[0130] Furthermore, when heated further from the color-developing state, the condensed structure of the color-developing state is destroyed, and when the temperature becomes lower than the color-developing temperature, the color developer becomes a separate and stable crystalline state, separating from the fluorane dimer compound of the present invention and decolorizing.

[0131] As a color-reducing agent, examples include amphoteric compounds having at least one phenolic hydroxyl group and a carboxyl group, and having an amino group as a functional group or as part of a salt compound, or salts or complex salts formed by compounds having at least one phenolic hydroxyl group and / or a carboxyl group and an aliphatic amine. Examples include aliphatic amines, aminobenzoic acids, hydroxyaminobenzoic acids, or their ester compounds.

[0132] As a long-chain chromogenic agent, examples include compounds having the following groups within the molecule: groups having chromogenic properties for the fluorane dimer compounds of the present invention, such as phenolic hydroxyl groups, carboxyl groups, etc., connected to groups that control intermolecular cohesion, such as long-chain hydrocarbon groups.

[0133] Example The present invention will be specifically described below through embodiments, but the present invention is not limited to the following embodiments.

[0134] (Example 1) Preparation of Compound Example 1 [Chemical Formula 9] (Compound Example 1) 18.5 g of compound (3-a) and 7.9 g of compound (4-a) were mixed in 75 g of 98% sulfuric acid and stirred at 40-50 °C for 20 hours.

[0135] [Chemical Formula 10] After cooling to room temperature, the reaction mixture was drained into 400g of ice water, and the precipitate was filtered off. The precipitate was then stirred under reflux for 1 hour with 200mL of toluene and 100g of 25% sodium hydroxide aqueous solution. After cooling, the toluene layer was separated and washed with hot water until neutral.

[0136] The toluene layer was concentrated under reduced pressure, 150 mL of methanol was added, and the mixture was stirred under reflux for 1 hour. After cooling, the precipitate was filtered off, washed with 50 mL of methanol, and dried to obtain 18.7 g of light pinkish-white powder as the target product.

[0137] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0138] ESI-Mass: 953 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.62%, H: 6.30%, N: 2.98%) Theoretical values ​​(C: 80.65%, H: 6.34%, N: 2.94%) 5% weight loss temperature: 359.8℃ It should be noted that the 5% weight loss temperature is the temperature at which the weight decreases by 5% through thermogravimetric differential thermal analysis, and the same applies below.

[0139] (Example 2) Preparation of Compound Example 2 [Chemical Formula 11] (Compound Example 2) Instead of 18.5g of compound (3-a) in Example 1, 24.1g of compound (3-b) was used, and otherwise, 19.3g of white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0140] [Chemical Formula 12] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0141] ESI-Mass: 1178 (M+H)+ Elemental analysis values: Measured values ​​(C: 81.57%, H: 7.83%, N: 2.41%) Theoretical values ​​(C: 81.59%, H: 7.87%, N: 2.38%) 5% weight loss temperature: 359.8℃ (Example 3) Preparation of Compound Example 4 [Chemical Formula 13] (Compound Example 4) Instead of 18.5g of compound (3-a) in Example 1, 19.3g of compound (3-c) was used, and otherwise, 16.8g of a light brownish-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0142] [Chemical Formula 14] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0143] ESI-Mass: 985 (M+H)+ Elemental analysis values: Measured values ​​(C: 77.98%, H: 6.11%, N: 2.87%) Theoretical values ​​(C: 78.03%, H: 6.14%, N: 2.84%) 5% weight loss temperature: 353.4℃ (Example 4) Preparation of Compound Example 9 [Chemical Formula 15] (Compound Example 9) Instead of 18.5g of compound (3-a) in Example 1, 20.1g of compound (3-d) was used, and otherwise, 19.9g of a light pinkish-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0144] [Chemical Formula 16] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0145] ESI-Mass: 1017 (M+H)+ Elemental analysis values: Measured values ​​(C: 75.53%, H: 5.90%, N: 2.79%) Theoretical values ​​(C: 75.57%, H: 5.95%, N: 2.75%) 5% weight loss temperature: 344.9℃ (Example 5) Preparation of Compound Example 13 [Chemical Formula 17] (Compound Example 13) Instead of 18.5g of compound (3-a) in Example 1, 20.1g of compound (3-d) was used, instead of 7.9g of compound (4-a) was used, and 9.8g of compound (4-b) was used. Otherwise, 17.3g of a light orange-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0146] [Chemical Formula 18] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0147] ESI-Mass: 1093 (M+H)+ Elemental analysis values: Measured values ​​(C: 76.86%, H: 5.88%, N: 2.58%) Theoretical values ​​(C: 76.90%, H: 5.90%, N: 2.56%) 5% weight loss temperature: 344.1℃ (Example 6) Preparation of Compound Example 23 [Chemical Formula 19] (Compound Example 23) Instead of 18.5g of compound (3-a) in Example 1, 21.3g of compound (3-e) was used, and otherwise, 15.3g of a light purple-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0148] [Chemical Formula 20] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0149] ESI-Mass: 1065 (M+H)+ Elemental analysis values: Measured values ​​(C: 76.65%, H: 5.64%, N: 2.66%) Theoretical values ​​(C: 76.67%, H: 5.68%, N: 2.63%) 5% weight loss temperature: 355.0℃ (Example 7) Preparation of Compound Example 35 [Chemical Formula 21] (Compound Example 35) Instead of 18.5g of compound (3-a) in Example 1, 18.5g of compound (3-f) was used, and otherwise, 20.8g of a light purple-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0150] [Chemical Formula 22] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0151] ESI-Mass: 953 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.61%, H: 6.29%, N: 2.97%) Theoretical values ​​(C: 80.65%, H: 6.34%, N: 2.94%) 5% weight loss temperature: 361.5℃ (Example 8) Preparation of Compound Example 36 [Chemical Formula 23] (Compound Example 36) Instead of 18.5 g of compound (3-a) in Example 1, 20.0 g of compound (3-g) was used, and otherwise, 17.1 g of a light purple-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0152] [Chemical Formula 24] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0153] ESI-Mass: 1013 (M+H)+ Elemental analysis values: Measured values ​​(C: 78.20%, H: 6.33%, N: 2.79%) Theoretical values ​​(C: 78.24%, H: 6.37%, N: 2.76%) 5% weight loss temperature: 310.4℃ (Example 9) Preparation of Compound Example 47 [Chemical Formula 25] (Compound Example 47) Instead of 18.5g of compound (3-a) in Example 1, 15.7g of compound (3-h) was used, instead of 7.9g of compound (4-a), 6.6g of compound (4-c) was used. Otherwise, 16.0g of a light pinkish-white powder as the target product was obtained by the same manufacturing method as in Example 1.

[0154] [Chemical Formula 26] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0155] ESI-Mass: 791 (M+H)+ Elemental analysis values: Measured values ​​(C: 78.93%, H: 5.31%, N: 3.60%) Theoretical values ​​(C: 78.97%, H: 5.35%, N: 3.54%) 5% weight loss temperature: 165.3℃ (Example 10) Preparation of Compound Example 48 [Chemical Formula 27] (Compound Example 48) Instead of 18.5g of compound (3-a) in Example 1, 20.1g of compound (3-d) was used, instead of 7.9g of compound (4-a) was used, and 6.6g of compound (4-c) was used. Otherwise, 14.0g of white powder was obtained by the same manufacturing method as in Example 1.

[0156] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0157] ESI-Mass: 967 (M+H)+ Elemental analysis values: Measured values ​​(C: 74.48%, H: 6.02%, N: 2.92%) Theoretical values ​​(C: 74.52%, H: 6.05%, N: 2.90%) 5% weight loss temperature: 345.4℃ (Example 11) Preparation of Compound Example 71 [Chemical Formula 28] (Compound Example 71) Instead of 18.5g of compound (3-a) in Example 1, 15.7g of compound (3-h) was used, instead of 7.9g of compound (4-a) in Example 1, 9.8g of compound (4-b) was used. Otherwise, 14.5g of light pinkish-white powder was obtained by the same manufacturing method as in Example 1.

[0158] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0159] ESI-Mass: 917 (M+H)+ Elemental analysis values: Measured values ​​(C: 81.17%, H: 5.26%, N: 3.08%) Theoretical values ​​(C: 81.20%, H: 5.28%, N: 3.05%) 5% weight loss temperature: 339.7℃ (Example 12) Preparation of Compound Example 73 [Chemical Formula 29] (Compound Example 73) Instead of 18.5 g of compound (3-a) in Example 1, 15.7 g of compound (3-h) was used, and otherwise, 15.3 g of a light brownish-white powder was obtained by the same manufacturing method as in Example 1.

[0160] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0161] ESI-Mass: 841 (M+H)+ Elemental analysis values: Measured values ​​(C: 79.95%, H: 5.26%, N: 3.36%) Theoretical values ​​(C: 79.98%, H: 5.27%, N: 3.33%) 5% weight loss temperature: 356.3℃ (Example 13) Preparation of Compound Example 75 [Chemical Formula 30] (Compound Example 75) Instead of 18.5 g of compound (3-a) in Example 1, 21.3 g of compound (3-i) was used, and otherwise 24.3 g of a light orange-white powder was obtained by the same manufacturing method as in Example 1.

[0162] [Chemical Formula 31] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0163] ESI-Mass: 1065 (M+H)+ Elemental analysis values: Measured values ​​(C: 81.13%, H: 7.15%, N: 2.67%) Theoretical values ​​(C: 81.17%, H: 7.19%, N: 2.63%) 5% weight loss temperature: 354.5℃ (Example 14) Preparation of Compound Example 79 [Chemical Formula 32] (Compound Example 79) Instead of 18.5 g of compound (3-a) in Example 1, 16.4 g of compound (3-j) was used, and otherwise, 18.3 g of a light pinkish-white powder was obtained by the same manufacturing method as in Example 1.

[0164] [Chemical Formula 33] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0165] ESI-Mass: 869 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.13%, H: 5.53%, N: 3.25%) Theoretical values ​​(C: 80.16%, H: 5.57%, N: 3.22%) 5% weight loss temperature: 370.5℃ (Example 15) Preparation of Compound Example 80 [Chemical Formula 34] (Compound Example 80) Instead of 18.5 g of compound (3-a) in Example 1, 19.2 g of compound (3-k) was used, and otherwise, 19.0 g of a light brownish-white powder was obtained by the same manufacturing method as in Example 1.

[0166] [Chemical Formula 35] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0167] ESI-Mass: 981 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.77%, H: 6.53%, N: 2.87%) Theoretical values ​​(C: 80.79%, H: 6.57%, N: 2.85%) 5% weight loss temperature: 357.2℃ (Example 16) Preparation of Compound Example 91 [Chemical Formula 36] (Compound Example 91) Instead of 18.5g of compound (3-a) in Example 1, 18.5g of compound (3-f) was used, instead of 7.9g of compound (4-a), 6.6g of compound (4-c) was used. Otherwise, 17.0g of a light red beige powder was obtained by the same manufacturing method as in Example 1.

[0168] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0169] ESI-Mass: 903 (M+H)+ Elemental analysis values: Measured values ​​(C: 79.78%, H: 6.44%, N: 3.13%) Theoretical values ​​(C: 79.80%, H: 6.47%, N: 3.10%) 5% weight loss temperature: 356.0℃ (Example 17) Preparation of Compound Example 92 [Chemical Formula 37] (Compound Example 92) Instead of 18.5g of compound (3-a) in Example 1, 16.4g of compound (3-j) was used, instead of 7.9g of compound (4-a) was used, and 6.6g of compound (4-c) was used. Otherwise, 18.0g of a light red beige powder was obtained by the same manufacturing method as in Example 1.

[0170] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0171] ESI-Mass: 819 (M+H)+ Elemental analysis values: Measured values ​​(C: 79.18%, H: 5.63%, N: 3.45%) Theoretical values ​​(C: 79.20%, H: 5.66%, N: 3.42%) 5% weight loss temperature: 355.3℃ (Example 18) Preparation of Compound Example 93 [Chemical Formula 38] (Compound Example 93) Instead of 18.5g of compound (3-a) in Example 1, 21.3g of compound (3-i) was used, instead of 7.9g of compound (4-a) was used, and 6.6g of compound (4-c) was used. Otherwise, 21.1g of beige powder was obtained by the same manufacturing method as in Example 1.

[0172] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0173] ESI-Mass: 1015 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.41%, H: 7.33%, N: 2.79%) Theoretical values ​​(C: 80.44%, H: 7.35%, N: 2.76%) 5% weight loss temperature: 353.8℃ (Example 19) Preparation of Compound Example 94 [Chemical Formula 39] (Compound Example 94) Instead of 18.5g of compound (3-a) in Example 1, 19.2g of compound (3-k) was used, instead of 7.9g of compound (4-a) was used, and 6.6g of compound (4-c) was used. Otherwise, 16.5g of light brown powder was obtained by the same manufacturing method as in Example 1.

[0174] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0175] ESI-Mass: 931 (M+H)+ Elemental analysis values: Measured values ​​(C: 79.95%, H: 6.69%, N: 3.05%) Theoretical values ​​(C: 79.97%, H: 6.71%, N: 3.01%) 5% weight loss temperature: 343.5℃ (Example 20) Preparation of Compound Example 123 [Chemical Formula 40] (Compound Example 123) Instead of 7.9 g of compound (4-a) in Example 7, 7.9 g of compound (4-d) was used, and otherwise, 19.8 g of a light brownish-white powder as the target product was obtained by the same method as in Example 7.

[0176] [Chemical Formula 41] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0177] ESI-Mass: 953 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.59%, H: 6.31%, N: 2.97%) Theoretical values ​​(C: 80.65%, H: 6.34%, N: 2.94%) 5% weight loss temperature: 346.2℃ (Example 21) Preparation of Compound Example 124 [Chemical Formula 42] (Compound Example 124) Instead of 7.9 g of compound (4-a) in Example 13, 7.9 g of compound (4-d) was used, and otherwise, 15.8 g of a light brownish-white powder as the target product was obtained by the same method as in Example 13.

[0178] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0179] ESI-Mass: 1065 (M+H)+ Elemental analysis values: Measured values ​​(C: 81.15%, H: 7.23%, N: 2.60%) Theoretical values ​​(C: 81.17%, H: 7.19%, N: 2.63%) 5% weight loss temperature: 341.2℃ (Example 22) Preparation of Compound Example 125 [Chemical Formula 43] (Compound Example 125) Instead of 7.9 g of compound (4-a) in Example 14, 7.9 g of compound (4-d) was used, and otherwise, 13.9 g of a light brownish-white powder as the target product was obtained by the same method as in Example 14.

[0180] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0181] ESI-Mass: 869 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.13%, H: 5.60%, N: 3.18%) Theoretical values ​​(C: 80.16%, H: 5.57%, N: 3.22%) 5% weight loss temperature: 349.2℃ (Example 23) Preparation of Compound Example 126 [Chemical Formula 44] (Compound Example 126) Instead of 7.9 g of compound (4-a) in Example 15, 7.9 g of compound (4-d) was used, and otherwise, 15.2 g of a light brownish-white powder as the target product was obtained by the same method as in Example 15.

[0182] Based on the following analytical results, the obtained compound was confirmed as the target compound.

[0183] ESI-Mass: 981 (M+H)+ Elemental analysis values: Measured values ​​(C: 80.75%, H: 6.60%, N: 2.81%) Theoretical values ​​(C: 80.79%, H: 6.57%, N: 2.85%) 5% weight loss temperature: 341.5℃ (Examples 24-46) Preparation of experimental thermal recording materials For Examples 1 to 23, the experimental thermal recording materials were prepared and evaluated as follows. Additionally, as a comparative example, the same experimental thermal recording material was prepared using the following comparative compound 1 and evaluated.

[0184] [Chemical Formula 45] (Compare compound 1) [Preparation of experimental thermal recording materials] 45g of a 2.5% polyvinyl alcohol aqueous solution was mixed with 5g of the compounds prepared in Examples 1 to 19 and the comparative compound, and the mixture was pulverized to an average particle size of 1 micrometer to prepare a dispersion.

[0185] On the other hand, 10g of bisphenol A, 10g of p-benzylbiphenyl, and 80g of 2.5% polyvinyl alcohol aqueous solution were pulverized together using a sand mill to achieve an average particle size of 3μm, thus preparing a dispersion.

[0186] After mixing the two dispersions prepared in this way, add 30g of 50% calcium carbonate dispersion and 30% paraffin dispersion, mix thoroughly, and prepare a heat-sensitive coating solution.

[0187] The prepared thermal coating solution was applied at a solid component concentration of 5 g / m². 2 Coated in a manner with a weight of 50 g / m 2 On high-quality paper, after drying, the material is calendered to achieve a Beck smoothness of 400-500 seconds on the thermal recording surface, thus producing a white experimental thermal recording material.

[0188] [Quality Performance Test] The thermal recording materials used in the above tests from the Examples and Comparative Examples are evaluated as follows.

[0189] (Determination of substrate whiteness) The whiteness of the uncolored areas of the thermal recording material used in the test was determined using a Macbeth RD-914 reflectance density meter based on OD values. The results are shown in Table 1. Lower values ​​indicate higher whiteness of the uncolored areas.

[0190] (Determination of substrate stability) After irradiating the test thermal recording material with a 20,000 lux fluorescent lamp for 72 hours, the lightfastness of the substrate was determined using a reflectance concentration meter RD-914 based on the substrate coloring concentration (OD value).

[0191] Similarly, after the test thermal recording material was kept at 60°C in a Yamato DS44 electric dryer for 24 hours, the heat resistance of the substrate was determined using a reflectance concentration meter RD-914 based on the substrate coloring concentration (OD value).

[0192] The results are shown in Table 1. The lower the value after the experiment, the higher the stability of the substrate.

[0193] (Stability test of color development image) The pulse width was adjusted and printed using the TH-PMD printing device of Okura Electric to achieve a color image density (OD value) of approximately 1.1 on the thermal recording material used in the experiment, resulting in a magenta color image.

[0194] The following experiments were conducted on the obtained colorimetric images. The concentration of the residual images after each experiment was measured based on OD values ​​using a Macbeth RD-914 reflectance density meter to evaluate the stability of the colorimetric images.

[0195] Regarding lightfastness, the concentration of residual image was measured after the chromatic image was irradiated with a 20,000 lux fluorescent lamp at 25°C for 72 hours.

[0196] Regarding resistance to damp heat, the concentration of the residual image was measured after the chromogenic image was kept in a TABAI ESPEC LHU-112M thermo-humidifier at 90%RH and 50℃ for 24 hours.

[0197] Regarding heat resistance, the concentration of residual image was measured after the colorimetric image was kept at 60°C in a Yamato DS44 electric dryer for 24 hours.

[0198] The stability of the color rendering image is expressed by the following formula.

[0199] Residual rate (%) = (Residual image concentration after the test / Colorimetric image concentration before the test) × 100 The results are shown in Table 1. A higher residual rate indicates higher stability of the color development image.

[0200] [Table 10] Industrial availability Recording materials using the fluorane dimer compounds of the present invention exhibit excellent whiteness of the substrate before color development, and excellent heat resistance and lightfastness in substrate stability, thus resulting in excellent storage stability. Furthermore, after color development, the image fastness exhibits excellent performance in terms of resistance to damp heat, heat resistance, and lightfastness, thus stably providing vivid magenta color developed images.

[0201] Thus, the fluorane dimer compounds of the present invention are very useful as chromogenic agents for thermal recording materials.

[0202] This application claims priority based on Japanese Patent Application No. 2023-184457, filed on October 27, 2023, the entire disclosure of which is incorporated herein by reference.

Claims

1. The fluorane dimer compounds represented by the following general formula (1), [Chemical Formula 1] In formula (1), R1 and R2 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted aryl group. R1 and R2 can bond with each other to form an aliphatic ring. R3 to R6 each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, and a substituted or unsubstituted arylthio group. R3 to R6 can bond with each other to form an aliphatic ring or an aromatic ring. R7 represents a hydrogen atom or an unsubstituted alkyl group. Q represents an unsubstituted benzene ring or an unsubstituted naphthalene ring, A is selected from substituted or unsubstituted aryl groups or groups represented by the following general formula (2), and n represents 0 or 1. [Chemical Formula 2] In formula (2), Z represents an oxygen atom, a sulfur atom, a phenylene group, a ketone group, or a substituted or unsubstituted alkylene group; R8 represents a hydrogen atom or an unsubstituted alkyl group; and l and m each independently represent 0 or 1. When l is 0, m represents 1, and when m is 0, l represents 1. It should be noted that (*) represents the bonding position.

2. The fluorane dimer compound as described in claim 1, wherein, Q represents an unsubstituted benzene ring.

3. The fluorane dimer compound as described in claim 1, wherein, Q represents an unsubstituted naphthalene ring.

4. The fluorane dimer compound as described in claim 1, wherein, R1 and R2 are each independently a hydrogen atom, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted aralkyl group with 7 to 25 carbon atoms, or a substituted or unsubstituted aryl group with 6 to 24 carbon atoms. R1 and R2 can bond with each other to form a heterocyclic aliphatic ring with 4 to 20 carbon atoms.

5. The fluorane dimer compound of claim 1, wherein, R3 to R6 each independently represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group with 1 to 20 carbon atoms, a substituted or unsubstituted alkoxy group with 1 to 25 carbon atoms, a substituted or unsubstituted aryloxy group with 6 to 25 carbon atoms, a substituted or unsubstituted alkylthio group with 1 to 25 carbon atoms, or a substituted or unsubstituted arylthio group with 6 to 25 carbon atoms. R3 to R6 can bond with each other to form a carbocyclic aliphatic ring with 5 to 20 carbon atoms or a carbocyclic aromatic ring with 6 to 20 carbon atoms.

6. The fluorane dimer compound of claim 1, wherein, R7 is a hydrogen atom or an unsubstituted alkyl group having 1 to 8 carbon atoms.

7. The fluorane dimer compound of claim 1, wherein, A is a substituted or unsubstituted aryl group having 6 to 18 carbon atoms, or a group represented by the general formula (2). In the general formula (2), Z represents an oxygen atom, a sulfur atom, a ketone group, or a substituted or unsubstituted alkylene group with 1 to 20 carbon atoms, and R8 represents a hydrogen atom or an alkyl group with 1 to 4 carbon atoms.

8. Recording material, which comprises electron-donating chromophores and electron-accepting chromophores, and utilizes their colorimetric reactions, wherein, The electron-donating colorant comprises at least one of the fluorane dimer systems according to any one of claims 1 to 7.

9. A thermal recording material formed from the recording material of claim 8.

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