Novel color developer and recording material

Abstract

To provide a recording material that serves as a thermal recording layer for thermal recording paper, where printed portions exhibit excellent thermal stability.SOLUTION: The invention provides: a sulfonylurea-based compound; a color developer containing the compound; a recording material containing the color developer; a thermal recording layer containing the recording material; and thermal recording paper having the thermal recording layer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a novel colour developer and a recording material containing said colour developer. [Background technology]

[0002] Conventionally, many scientific color-developing systems using energy such as heat, pressure, and light are known. Among them, color-developing systems consisting of a two-component color-developing system of a leuco dye, which is a dye precursor, and a color developer that develops color when it comes into contact with the leuco dye, are widely used in recording materials. For example, a thermal recording material is generally prepared by dispersing a leuco dye and a color developer such as a phenolic compound into fine particles, mixing the two, adding additives such as a binder, a sensitizer, a filler, and a lubricant, and applying the resulting coating liquid to paper, film, synthetic paper, etc., and obtaining a colored record (print) by a chemical reaction that occurs when one or both of the leuco dye and the color developer melt and come into contact with each other when heated.

[0003] In order to develop color in such thermal recording materials, a thermal printer with a built-in thermal head is used. Compared to other recording methods, the thermal recording method has the following features: (1) no noise is generated during recording, (2) no development or fixing is required, (3) no maintenance is required, and (4) the machines are relatively inexpensive. Therefore, it is widely used in the fields of facsimile, computer output, printers such as calculators, recorders for medical measurement, automatic ticket vending machines, thermal recording labels, etc.

[0004] In recent years, the applications of recording materials containing leuco dyes and color developers have expanded by utilizing the reversible reaction between colorants and leuco dyes, to include thermochromic materials in the food and beverage industry, and color-changing materials in toys and writing implements, etc. As the use environments become more diverse due to the expansion of applications, the resulting color-developing records are required to have resistance to various environments, such as heat resistance, moisture resistance, water resistance, light resistance, oil resistance, alcohol resistance, and plasticity resistance.

[0005] Generally, color-developing compounds having a phenolic hydroxyl group have high color-developing ability, and many bisphenol-based compounds, such as 2,2-bis(4-hydroxyphenylpropane) (bisphenol A) shown in Patent Document 1 and 4,4'-dihydroxydiphenylsulfone (bisphenol S) shown in Patent Document 2, have been reported due to their high color-developing density. However, the use of phenol-based compounds such as bisphenol A is problematic due to endocrine problems, and non-phenol-based color-developing compounds that do not contain a phenol structure are in demand. As non-phenol-based color-developing agents, diphenylurea-based color-developing compounds shown in Patent Documents 3 and 4 have been reported. However, the diphenylurea-based compounds shown in these documents have low thermal stability and plasticity resistance compared to phenol-based compounds, and have the disadvantage that the color-developing record fades or disappears when exposed to heat for a relatively short time or when used as a food label, so that there are certain restrictions on the expansion of applications. In addition, sulfonylurea-based color-developing compounds shown in Patent Documents 5 and 6 have been reported, but no compounds that satisfy the market demands in a balanced manner have been obtained, and there is a strong demand for the development of recording materials with excellent thermal stability and plasticity resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] U.S. Pat. No. 3,539,375 [Patent Document 2] Japanese Patent Application Publication No. 57-11088 [Patent Document 3] International Publication 2014 / 080615 [Patent Document 4] Japanese Patent Application Publication No. 8-59603 [Patent Document 5] Japanese Patent Application Publication No. 6-64334 [Patent Document 6] Japanese Patent Application Publication No. 8-156426 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a recording material which has good color development in the printed portion, and is excellent in thermal stability and plasticity resistance. [Means for solving the problem]

[0008] Means for Solving the Problems The present inventors have conducted extensive research to achieve the above object and have found that a compound having a specific structure can solve the above problems as a developer, thereby completing the present invention. That is, the present invention is [1] The following general formula (1) or (2):

[0009] [ka]

[0010] (In formulas (1) and (2), R 1 R represents a substituted or unsubstituted linear or branched alkyl group having 1 to 18 carbon atoms. 2 represents a substituted or unsubstituted linear or branched alkyl group having 1 to 18 carbon atoms; and n represents 1 or 2. [2] R 1 is a substituted or unsubstituted linear or branched alkyl group having 3 to 12 carbon atoms; R 2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, and n is 1 or 2; [3] R 1 is a substituted or unsubstituted linear or branched alkyl group having 4 to 8 carbon atoms; R 2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, and n is 2; [4] A color developer comprising the color developer according to any one of the preceding items [1] to [3]. [5] A recording material containing the developer according to the preceding item [4]. [6] A heat-sensitive recording layer comprising the recording material according to the preceding item [5]. [7] A thermal recording paper having the thermal recording layer described in the preceding paragraph [6], and [8] An ink containing the recording material according to the preceding paragraph [7]. Regarding. Effect of the Invention

[0011] By using the compound represented by formula (1) or (2) as a developer, it is possible to provide a recording material which exhibits good color development in the printed portion, high thermal stability and resistance to plasticity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The compound of the present invention is represented by the above general formula (1) or (2).

[0013] In formulas (1) and (2), R 1 represents a linear or branched alkyl group having 1 to 18 carbon atoms, and the alkyl group may have a substituent. 2 represents a linear or branched alkyl group having 1 to 18 carbon atoms, and the alkyl group may have a substituent. n represents 1 or 2.

[0014] R in formulas (1) and (2) 1 The alkyl group represented by R in formulas (1) and (2) may be either a straight chain or a branched chain as long as it has 1 to 18 carbon atoms, and is preferably a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, or an octyl group having 4 to 8 carbon atoms, and more preferably a butyl group, a pentyl group, or a hexyl group. 2 The alkyl group represented by may be either a straight chain or a branched chain so long as it has 1 to 18 carbon atoms, and is preferably a methyl group, ethyl group, propyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group or octyl group having 1 to 8 carbon atoms, and more preferably a methyl group, ethyl group, propyl group, butyl group, pentyl group or hexyl group.

[0015] R in formulas (1) and (2) 1 , R2 The alkyl group represented by may have a substituent, and examples of the substituent include halogen, a hydroxy group, a carboxy group, a sulfo group, an alkylthio group, an alkylamino group, and an ester group, and a fluorine atom, a chlorine atom, and a hydroxy group are preferred. 1 , R 2 The number of substituents on the alkyl group represented by the formula (I) and the positions of the substituents are not particularly limited. In this specification, the term "substituted alkyl group" refers to an alkyl group in which a hydrogen atom of the alkyl group is substituted with a substituent, atom, etc., and the term "unsubstituted alkyl group" refers to an alkyl group in which a hydrogen atom of the alkyl group is not substituted with a substituent, atom, etc. (i.e., a saturated hydrocarbon group).

[0016] Next, the process for producing the compound of the present invention will be described. The compound of the present invention can be produced by a method according to the production flow shown below. 1 , R 2 is R in formulas (1) and (2). 1 , R 2 It has the same meaning as:

[0017] [ka]

[0018] [ka]

[0019] First, 2-(4-nitrophenyl)alcohol represented by formula (A-1) or 2-(3-nitrophenyl)alcohol represented by formula (A-2) is reacted with an acid chloride represented by formula (B) in the presence of a base to obtain a compound represented by formula (1-1) or formula (1-2). Next, the compound represented by formula (1-1) or formula (1-2) is reduced by a general method for reducing a nitro group, such as hydrogenation or hydrazine reduction, to obtain an amine compound represented by formula (2-1) or formula (2-2). Finally, the compound represented by formula (1) or (2) can be produced by reacting the amine compound represented by formula (2-1) or formula (2-2) with an isocyanate represented by formula (C) in the presence or absence of a base.

[0020] Examples of the base that may be used if desired in the above-mentioned production method include inorganic bases such as sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, sodium carbonate, potassium hydrogen carbonate, potassium carbonate, and cesium carbonate, and organic bases such as triethylamine and diisopropylethylamine. The amount of these bases used is preferably 1 to 3 times the number of moles of the acid chloride represented by formula (B) or the isocyanates represented by formula (C).

[0021] The solvent used in the above-mentioned production method is not particularly limited as long as it does not affect the reaction. When 2-(4-nitrophenyl)alcohol represented by formula (A-1) or 2-(3-nitrophenyl)alcohol represented by formula (A-2) is reacted with an acid chloride represented by formula (B) in the presence of a base, or when an amine compound represented by formula (2-1) or formula (2-2) is reacted with an isocyanate represented by formula (C), for example, amide compounds such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; halogenated hydrocarbon compounds such as methylene chloride and chloroform; 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; and sulfoxide compounds such as dimethyl sulfoxide may be used. These may be used alone or in admixture. When the compound represented by formula (1-1) or formula (1-2) is reduced by a general method for reducing a nitro group, such as hydrogenation or hydrazine reduction, alcohols such as ethanol and isopropanol, water, etc. are used. These may be used alone or in admixture.

[0022] In the above production process, the reaction temperature is usually −78 to 100° C., preferably 0 to 80° C., and the reaction time is usually 10 minutes to 24 hours.

[0023] The recording material of the present invention contains a developer containing the compound of the present invention, and preferably a color-forming compound, a sensitizer and a binder, and may further contain a storage stability improver, a filler and other additives as optional components. It is also possible to use both of the compounds of the present invention in combination. The content of each component in the recording material of the present invention, in terms of the mass ratio in the recording material, is preferably 1 to 70 mass %, more preferably 5 to 50 mass %, of a developer containing the compound of the present invention; preferably 1 to 50 mass %, more preferably 5 to 30 mass %, of a color-forming compound; preferably 1 to 80 mass %, of a sensitizer; preferably 1 to 90 mass %, of a binder; preferably 30 mass % or less of a storage stability improver; preferably 80 mass % or less of a filler; and preferably 30 mass % or less of other additives (lubricants, surfactants, defoamers, UV absorbers, etc.).

[0024] In a more preferred embodiment, the developer containing the compound of the present invention is used in an amount of 0.5 to 20 parts by mass, and particularly preferably 1 to 5 parts by mass, per part by mass of the color-forming compound. The recording material of the present invention may be used in combination with a developer other than the compound of the present invention, provided that the effect of the invention is not impaired.

[0025] The color developer other than the compound of the present invention that can be used in combination with the recording material of the present invention is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Examples of the color developer include α-naphthol, β-naphthol, p-octylphenol, 4-t-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, and the like. Tan, 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'-dihydroxydiphenyl sulfone, 4-hydroxy-4'-methoxydiphenyl sulfone, 2,4'-dihydroxydiphenyl sulfone, 4 -Hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-4'-ethoxydiphenyl sulfone, 4-hydroxy-4'-butoxydiphenyl sulfone, 4-hydroxy-4'-benzyloxydiphenyl sulfone, methyl bis(4-hydroxyphenyl)acetate, butyl bis(4-hydroxyphenyl)acetate, benzyl bis(4-hydroxyphenyl)acetate, 2,4-dihydroxy-2'-methoxybenzanilide and other phenolic compounds, benzyl p-hydroxybenzoate, Examples of the aromatic carboxylic acid derivatives include ethyl p-hydroxybenzoate, dibenzyl 4-hydroxyphthalate, dimethyl 4-hydroxyphthalate, ethyl 5-hydroxyisophthalate, 3,5-di-t-butylsalicylic acid, and 3,5-di-α-methylbenzylsalicylic acid; aromatic carboxylic acids or polyvalent metal salts thereof; and diphenylurea compounds such as those described in JP2002-532441, WO2014 / 080615, WO2017 / 111032, WO2019 / 044462, and JP2803078.

[0026] The color-forming compound preferably used in the recording material of the present invention is not particularly limited as long as it is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Examples of the color-developing compound include fluoran-based compounds, triarylmethane-based compounds, spiro-based compounds, diphenylmethane-based compounds, thiazine-based compounds, lactam-based compounds, and fluorene-based compounds, with fluoran-based compounds being preferred.

[0027] Specific examples of fluoran-based compounds include 3-diethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isopentylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-isobutylamino)-6-methyl-7-anilinofluoran, 3-[N-ethyl-N-(3-ethoxypropyl)amino]-6-methyl-7-anilinofluoran, -Anilinofluoran, 3-(N-ethyl-N-hexylamino)-6-methyl-7-anilinofluoran, 3-dipentylamino-6-methyl-7-anilinofluoran, 3-(N-methyl-N-propylamino)-6-methyl-7-anilinofluoran, 3-(N-ethyl-N-tetrahydrofurylamino)-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(p-chloroanilino)fluoran, 3-diethylamino-6-methyl-7-(p-fluoroanilino)fluoran , 3-[N-ethyl-N-(p-tolyl)amino]-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-(p-toluidino)fluoran, 3-diethylamino-7-(o-chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-diethylamino-7-(o-fluoroanilino)fluoran, 3-dibutylamino-7-(o-fluoroanilino)fluoran, 3-diethylamino-7-(3,4-dichloroanilino)fluoran, 3-pyrrolidino-7-(o-fluoroanilino)fluoran, Examples of such fluoran include lysino-6-methyl-7-anilinofluoran, 3-diethylamino-6-chloro-7-ethoxyethylaminofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7-octylfluoran, and 3-[N-ethyl-N-(p-tolyl)amino]-6-methyl-7-phenethylfluoran, and 3-dibutylamino-6-methyl-7-anilinofluoran is preferred.

[0028] Specific examples of triarylmethane compounds include 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone or CVL), 3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3-(1,2-dimethylaminoindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, and 3-(p-dimethylaminophenyl)-3-(2-phenylindol-3-yl)phthalide. Examples of such phthalides include 3,3-bis(1,2-dimethylindol-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, and 3-p-dimethylaminophenyl-3-(1-methylpyrrol-2-yl)-6-dimethylaminophthalide.

[0029] Specific examples of spiro compounds include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho-(3-methoxybenzo)spiropyran, 1,3,3-trimethyl-6-nitro-8'-methoxyspiro(indoline-2,2'-benzopyran), and the like. Specific examples of diphenylmethane compounds include N-halophenyl-leucoauramine, 4,4-bis-dimethylaminophenyl benzhydryl benzyl ether, and N-2,4,5-trichlorophenyl leucoauramine. Specific examples of thiazine compounds include benzoyl leuco methylene blue, p-nitrobenzoyl leuco methylene blue, and the like.

[0030] Specific examples of lactam compounds include rhodamine B anilinolactam, rhodamine B p-chloroanilinolactam, and the like. Specific examples of fluorene-based compounds include 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-dimethylaminophthalide, 3,6-bis(dimethylamino)fluorene spiro(9,3')-6'-pyrrolidinophthalide, and 3-dimethylamino-6-diethylaminofluorene spiro(9,3')-6'-pyrrolidinophthalide. These color-forming compounds may be used alone or in combination.

[0031] Examples of sensitizers (heat-fusible compounds) preferably used in the recording material of the present invention include 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, and aromatic hydrocarbon compounds.

[0032] Examples of waxes include wood wax, carnauba wax, shellac, paraffin, montan wax, oxidized paraffin, polyethylene wax, and oxidized polyethylene; examples of higher fatty acids include stearic acid and behenic acid; examples of higher fatty acid amides include stearic acid amide, oleic acid amide, N-methylstearic acid amide, erucic acid amide, methylol behenic acid amide, methylene bisstearic acid amide, and ethylene bisstearic acid amide; examples of higher fatty acid anilides include stearic acid anilide and linoleic acid. anilides, etc.; naphthalene derivatives, for example, 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, 2,6-diisopropylnaphthalene, etc.; aromatic ethers, for example, 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, etc.; aromatic carboxylic acid derivatives, for example, p-hydroxybenzoic acid benzyl ester, p-benzyloxybenzoic acid benzyl ester, terephthalic acid dibenzyl ester, etc.; aromatic sulfonic acid ester derivatives, for example, p-toluenesulfonic acid phenyl ester, phenylmesitylenesulfonate, 4-methylphenylmesitylenesulfonate, 4-tolylmesitylenesulfonate, etc.; carbonic acid or oxalic acid diesters. Derivatives include, for example, diphenyl carbonate, dibenzyl oxalate, di(4-chlorobenzyl) oxalate, and di(4-methylbenzyl) oxalate; biphenyl derivatives include, for example, p-benzylbiphenyl and p-allyloxybiphenyl; terphenyl derivatives include, for example, m-terphenyl; sulfone derivatives include, for example, p-toluenesulfonamide, benzenesulfonanilide, p-toluenesulfonanilide, 4,4'-diallyloxydiphenyl sulfone, and diphenyl sulfone;Examples of aromatic ketone derivatives include 4,4'-dimethylbenzophenone and dibenzoylmethane; examples of aromatic hydrocarbon compounds include p-acetotoluidine;

[0033] Specific examples of binders preferably used in the heat-sensitive material of the present invention include water-soluble or (meth)soluble binders such as 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, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin, water-soluble isoprene rubber, alkali salts of styrene / maleic anhydride copolymers, and alkali salts of iso(or diiso)butylene / maleic anhydride copolymers. ) acrylic acid ester copolymers, styrene / (meth)acrylic acid ester copolymers, polyurethane, polyester polyurethane, polyether polyurethane, polyvinyl acetate, ethylene / vinyl acetate copolymer, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinylidene chloride, polystyrene, styrene / butadiene (SB) copolymer, carboxylated styrene / butadiene (SB) copolymer, styrene / butadiene / acrylic acid copolymer, acrylonitrile / butadiene (NB) copolymer, carboxylated acrylonitrile / butadiene (NB) copolymer, and hydrophobic polymer emulsions such as composite particles of colloidal silica and (meth)acrylic resin.

[0034] Specific examples of the storage stability improver that can be used in combination with the recording material of the present invention include 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'-hydroxypropyl)phenyl]-2,2'-diphenyl ... 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-tert-butyl-3-hydroxybenzyl)isocyanurate, 4,4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5' -Hindered phenol compounds such as tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3',5,5'-tetramethyldiphenyl sulfone, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenyl sulfone, 4-benzyloxy Examples of epoxy compounds include 4'-(2-methylglycidyloxy)diphenyl sulfone, diglycidyl terephthalate, cresol novolac epoxy resins, phenol novolac epoxy resins, and bisphenol A epoxy resins; N,N'-di-2-naphthyl-p-phenylenediamine; sodium or polyvalent metal salts of 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate; and bis(4-ethyleneiminocarbonylaminophenyl)methane.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]- 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-tert-butyl-3-hydroxybenzyl)isocyanurate, 4,4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5'-tetrabromodiphenylsulfone, 4,4'-dihydroxy-3,3',5,5'-tetramethyldiphenyl Nilsulfone, hindered phenol compounds such as 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,4-diglycidyloxybenzene, 4,4'-diglycidyloxydiphenylsulfone, 4-benzyloxy-4'-(2-methylglycidyloxy)diphenylsulfone, diglycidyl terephthalate, cresol novolac type epoxy Examples of the epoxy compounds include resins, phenol novolac epoxy resins, bisphenol A epoxy resins, and the like, N,N'-di-2-naphthyl-p-phenylenediamine, sodium or polyvalent metal salts of 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate, bis(4-ethyleneiminocarbonylaminophenyl)methane, urea urethane compounds (such as color developer UU manufactured by Chemipro Chemical Co., Ltd.), and diphenylsulfone crosslinked compounds represented by the following formula (3) or mixtures thereof. In formula (3), a is an integer of 0 to 6.

[0035] [ka]

[0036] Specific examples of fillers that can be used in combination with the recording material of the present invention include calcium carbonate, magnesium carbonate, magnesium oxide, silica, white carbon, talc, clay, alumina, magnesium hydroxide, aluminum hydroxide, aluminum oxide, barium sulfate, polystyrene resin, and urea-formalin resin.

[0037] Other additives that can be used in combination with the recording material of the present invention include, for example, higher fatty acid metal salts such as zinc stearate and calcium stearate, which are used for the purposes of preventing abrasion and sticking of thermal heads, ultraviolet absorbers such as phenol derivatives, benzophenone compounds, and benzotriazole compounds, which are used to impart antioxidant and anti-aging effects, and various surfactants and defoamers.

[0038] Next, a method for preparing the recording material and thermal recording paper of the present invention will be described. The color developer containing the compound represented by formula (1) or (2), which is an essential component of the recording material of the present invention, and the color-forming compound preferably used are pulverized and dispersed in a dispersing machine such as a ball mill, attritor or sand mill together with a binder or other additives used as necessary to prepare respective dispersions (usually, when pulverization or dispersion is performed in a wet manner, water is used as a medium), and then the dispersions are mixed to prepare a coating solution for the recording material, which is then coated on a support such as paper (plain paper, wood-free paper, coated paper, etc. can be used), a plastic sheet, or synthetic paper, in a dry weight of usually 1 to 20 g / m. 2 The coating is then applied by a bar coater, blade coater or the like so as to obtain a thermal recording paper having a thermal recording layer containing the recording material of the present invention. In this specification, the category of "thermosensitive recording paper" includes a support other than paper on which a thermosensitive recording layer is provided.

[0039] 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 or overcoat layer (protective layer) is prepared, for example, in the same manner as in the preparation of the coating solution for the recording material described above, by pulverizing and dispersing the components required for the intermediate layer or overcoat layer together with a binder or other additives used as necessary to prepare a coating solution, and then dispersing the resulting coating solution to a dry weight of usually 0.1 to 10 g / m. 2 The coating may be applied so as to have a thickness of about 100 nm and then dried to form the desired layer.

[0040] The coating liquid (dispersion) of the recording material of the present invention can also be contained in general inks for writing instruments or inks for inkjet printing. For example, a writing ink can be prepared by mixing a dispersion of the recording material with a water-based ink containing water as a solvent, a water-soluble organic solvent, a thickener, a lubricant, an anti-rust agent, a preservative, or an antibacterial agent, etc., which are appropriately blended depending on the application, or an oil-based ink containing a main solvent such as polypropylene glycol, polybutylene glycol, or polyoxypropylene diglyceryl ether, a resin, a lubricant, an anti-rust agent, a preservative, or an antibacterial agent, etc., which are appropriately blended depending on the application. EXAMPLES

[0041] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples, "parts" means parts by mass and "%" means % by mass.

[0042] Example 1 (Synthesis of compound represented by formula (1) (compound represented by formula (100-6) below)) 10.0 parts of 2-(4-nitrophenyl)ethanol (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (100-1) and 15.2 parts of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 30.0 parts of methyl isobutyl ketone, and the mixture was stirred at room temperature, and then cooled to 15°C. Next, 14.6 parts of n-octanoyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (100-2) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Next, 100.0 parts of water and 200 parts of ethyl acetate were added and stirred, and the oil layer was collected. The collected oil layer was concentrated using an evaporator to obtain an oily compound represented by formula (100-3). Next, 100.0 parts of ethanol was added to dissolve the oily compound represented by formula (100-3), and then 0.5 parts of palladium carbon (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60°C for 2 hours under a pressure of 1.2 MPa of hydrogen gas using an autoclave. After the reaction solution was filtered, the filtrate was concentrated using an evaporator to obtain an oily amine compound represented by formula (100-4). The oily amine compound represented by formula (100-4) was dissolved in 100.0 parts of acetone (manufactured by Kanto Chemical Industry Co., Ltd.), stirred at room temperature, and then cooled to 3°C. Next, 7.1 parts of p-toluenesulfonyl isocyanate represented by the following formula (100-5) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped and stirred at room temperature for 1 hour to precipitate crystals. The precipitate was filtered, washed with hexane and water in that order, and dried to obtain 7.4 parts of a white solid compound represented by the following formula (100-6).

[0043] [ka]

[0044] Example 2 (Synthesis of compound represented by formula (1) (compound represented by formula 101-6 below)) 10.0 parts of 2-(4-nitrophenyl)ethanol (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (101-1) and 15.2 parts of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 30.0 parts of methyl isobutyl ketone, and the mixture was stirred at room temperature, and then cooled to 15°C. Next, 10.9 parts of valeryl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (101-2) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Next, 100.0 parts of water and 200 parts of ethyl acetate were added and stirred, and the oil layer was collected. The collected oil layer was concentrated using an evaporator to obtain an oily compound represented by formula (101-3). Next, 300.0 parts of ethanol were added to dissolve the oily compound represented by formula (101-3), and then 0.5 parts of palladium carbon (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60°C for 2 hours under a pressure of 1.2 MPa of hydrogen gas using an autoclave. After the reaction liquid was filtered, the filtrate was concentrated using an evaporator to obtain an oily amine compound represented by formula (101-4). The oily amine compound represented by formula (101-4) was dissolved in 100.0 parts of acetone (manufactured by Kanto Chemical Industry Co., Ltd.), stirred at room temperature, and then cooled to 20°C. Next, 4.5 parts of p-toluenesulfonyl isocyanate represented by the following formula (101-5) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped and stirred at room temperature for 1 hour to precipitate crystals. The precipitate was filtered, washed with hexane and water in that order, and dried to obtain 3.1 parts of a white solid compound represented by the following formula (101-6).

[0045] [ka]

[0046] Example 3 (Synthesis of compound represented by formula (1) (compound represented by formula (102-6) below)) 9.2 parts of 4-nitrobenzyl alcohol (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (102-1) and 15.2 parts of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) were added to 30.0 parts of methyl isobutyl ketone, and the mixture was stirred at room temperature, and then cooled to 15°C. Then, 10.9 parts of valeryl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (102-2) was added dropwise, and the mixture was stirred at room temperature for 1 hour. Then, 100.0 parts of water and 200 parts of ethyl acetate were added and stirred, and the oil layer was collected. The collected oil layer was concentrated using an evaporator to obtain an oily compound represented by formula (102-3). Then, 300.0 parts of ethanol were added to dissolve the oily compound represented by formula (102-3), and 0.5 parts of palladium carbon (manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was stirred at 60°C for 2 hours under a pressure of 1.2 MPa of hydrogen gas using an autoclave. After the reaction solution was filtered, the filtrate was concentrated using an evaporator to obtain an oily amine compound represented by formula (102-4). The oily amine compound represented by formula (102-4) was dissolved in 100.0 parts of acetone (manufactured by Kanto Chemical Industry Co., Ltd.), stirred at room temperature, and then cooled to 20°C. Next, 4.5 parts of p-toluenesulfonyl isocyanate represented by the following formula (102-5) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dropped, and stirred at room temperature for 1 hour to precipitate crystals. The precipitate was filtered, washed with hexane and water in that order, and dried to obtain 2.1 parts of a white solid compound represented by the following formula (102-6).

[0047] [ka]

[0048] Examples 4, 5, 6 and Comparative Examples 1 and 2 (Preparation of Coating Solution for Recording Material and Preparation of Thermal Recording Paper Having a Thermal Recording Layer Containing the Recording Material) (Adjustment of solution [A]) Using a Multi-Beads Shocker (model: PV1001(S)) manufactured by Yasui Kikai Co., Ltd., the compound represented by formula (100-6) obtained in Example 1, the compound represented by formula (101-6) obtained in Example 2, the compound represented by formula (102-6) obtained in Example 3, the compound represented by formula (X) below in Example 1 of Patent Document 3, the compound represented by formula (Y) below in Synthesis Example 2 of Patent Document 4, and other components were mixed in the compositions shown in Table 1, and ground and dispersed for 1 hour to prepare liquid [A] (A-1 to A-5).

[0049] [ka]

[0050] [Table 1]

[0051] The "other ingredients" used in solution [A] are as follows: PVA aqueous solution: 20% aqueous solution of Gohsenex L-3266 (Mitsubishi Chemical) SF104: Surfynol 104PG-50 (50% propylene glycol solution of Surfynol 104 manufactured by Nissin Chemical Industry Co., Ltd.)

[0052] (Adjustment of solution [B]) A mixture of the following composition was ground and dispersed using a sand grinder to a median particle size of 1 μm as measured by a laser diffraction / scattering particle size distribution analyzer LA-950 (manufactured by Horiba, Ltd.) to prepare a color-developing compound solution [B]. 2-Anilino-6-dibutylamino-3-methylfluoran 35 parts PVA aqueous solution 40 parts Water 25 parts The components used in solution [B] are as follows: 2-Anilino-6-dibutylamino-3-methylfluoran: PSD-290 (manufactured by Nippon Soda Co., Ltd.) PVA aqueous solution: 15% aqueous solution of Gohsenex L-3266 (Mitsubishi Chemical)

[0053] (Adjustment of coating liquid for recording material) The above obtained liquid [A], liquid [B] and other components were mixed in the composition shown in Table 2 to prepare a coating liquid for the recording material.

[0054] [Table 2]

[0055] The "other components" used in the coating liquid for the recording material are as follows: CaCO3 dispersion: 67% aqueous dispersion of calcium carbonate (YCC-FD, Yabashi Industries) PVA aqueous solution: 15% aqueous solution of polyvinyl alcohol (PVA-110, manufactured by Kuraray Co., Ltd.) StZn dispersion: 37% aqueous dispersion of zinc stearate (manufactured by Goo Chemical Industry Co., Ltd.)

[0056] Examples 4, 5, 6 and Comparative Examples 1 and 2 (Preparation of Thermal Recording Paper) The coating liquids for the recording materials obtained in Examples 4, 5, and 6 and Comparative Examples 1 and 2 were applied to a recording medium having a basis weight of 50 g / m 2 Dry weight of 5g / m2 on wood-free paper 2 The thermal recording papers of the present invention and for comparison were prepared by coating and drying the respective compositions.

[0057] (Evaluation of color development of thermal recording paper) Using a thermal gradient tester (HG-100-2) manufactured by Toyo Seiki Seisakusho, each of the thermal recording papers obtained in Examples 4, 5, and 6 and Comparative Examples 1 and 2 was printed by hot pressing at 120°C for 1 second at a pressure of 0.15 MPa. Using a colorimeter manufactured by X-Rite, product name "eXact", the reflection density of the colored part of the printed matter was measured under the conditions of a light source of Illuminant C, a density standard of Status A, and a viewing angle of 2 degrees, and the Dk value, which is the reflection OD, was obtained, and the color development was evaluated according to the following evaluation criteria. The higher the Dk value, the better the color development. The results are shown in Table 3. Evaluation criteria ◎: Dk value is 0.4 or more ○: Dk value is 0.3 or more and less than 0.4 △: Dk value is 0.2 or more and less than 0.3 ×: Dk value is less than 0.2

[0058] (Evaluation of heat resistance of thermal recording paper) Using a thermal printer (TH-M2 / PP) manufactured by Okura Engineering Co., Ltd., printing was performed on each of the thermal recording papers obtained in Examples 4, 5, and 6 and Comparative Examples 1 and 2 with a pulse width of 1.4 msec, and the printouts were heated at 100° C. for 30 minutes. Using a colorimeter manufactured by X-Rite, product name "eXact," the reflection density of the colored portion of the sample before and after heating was measured under the conditions of a light source of Illuminant C, a density standard of Status A, and a viewing angle of 2 degrees. (Reflection density of colored area after heating) / (Reflection density of colored area before heating) x 100 The residual rate (%) of the colored portion was calculated using the formula above, and the heat resistance was evaluated according to the following evaluation criteria. A higher residual rate means better heat resistance. The results are shown in Table 3. Evaluation criteria ◎: Residual rate is 95% or more ○: Residual rate is 90% or more but less than 95% △: Residual rate is 85% or more but less than 90% ×: Residual rate is less than 85%

[0059] (Evaluation of the plasticity resistance of thermal recording paper) Using a thermal printer (TH-M2 / PP) manufactured by Okura Engineering Co., Ltd., printing was performed on each of the thermal recording papers obtained in Examples 4, 5, and 6 and Comparative Examples 1 and 2 with a pulse width of 1.4 msec. The printed surface of the printed matter was covered with Saran Wrap (registered trademark) manufactured by Asahi Kasei Home Products, and the printed matter was left at 45° C. for 2 hours, after which the Saran Wrap (registered trademark) was removed and the printed matter was collected. Using a colorimeter manufactured by X-Rite, product name "eXact," the reflection density of the colored part of the sample before and after being covered with the wrap was measured under the conditions of Illuminant C as the light source, Status A as the density standard, and a viewing angle of 2 degrees. Residual rate of colored area (%) = (reflection density of colored area after plasticity resistance test) / (reflection density of colored area before plasticity resistance test) x 100 The residual rate (%) of the colored portion was calculated using the formula above, and the heat resistance was evaluated according to the following evaluation criteria. A higher residual rate means better heat resistance. The results are shown in Table 3. Evaluation criteria ◎: Residual rate is 60% or more ○: Residual rate is 55% or more but less than 60% △: Residual rate is 50% or more but less than 55% ×: Residual rate is less than 50%

[0060] [Table 3]

[0061] From the results in Table 3 above, it can be said that the thermal recording paper of the embodiment, which uses a recording material containing a color developer including the compound of the present invention, has results of 0 or above in all items of color development, heat resistance, and plasticity resistance of the printed area (color development area) compared to the thermal recording paper of the comparative example, which uses a recording material containing the comparative color developer (the color developer described in Patent Documents 3 and 4), and therefore has superior performance to the comparative example.

Claims

1. The following general formula (1) or (2): 【Chemistry 1】 (In formulas (1) and (2), R １ R represents a substituted or unsubstituted linear or branched alkyl group having 1 to 18 carbon atoms. ２ represents a substituted or unsubstituted linear or branched alkyl group having 1 to 18 carbon atoms; and n represents 1 or 2. A compound containing a compound represented by the formula:

2. R １ is a substituted or unsubstituted linear or branched alkyl group having 3 to 12 carbon atoms; R ２ The compound according to claim 1, wherein: is a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms; and n is 1 or 2.

3. R １ is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms; R ２ The compound according to claim 2, wherein: is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms; and n is 2.

4. A colour developer comprising the compound according to claim 1 .

5. A recording material comprising the colour developer according to claim 4.

6. A heat-sensitive recording layer comprising the recording material according to claim 5.

7. A thermal recording paper having the thermal recording layer according to claim 6.

8. An ink comprising the recording material of claim 7.

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