Novel developer and recording material

Abstract

To provide a recording material in which a printing part is excellent in heat resistance and alcohol resistance.SOLUTION: There are provided a compound represented by the following general formula (1) (wherein, X represents a halogen atom, a straight or branched chain alkyl group having 1 to 8 carbon atoms, a straight or branched chain alkyl group having 1 to 8 carbon atoms. R1 represents a straight or branched chain alkyl group having 7 to 12 carbon atoms.), a developer containing the compound, a recording material containing the developer, a thermosensitive recording layer containing the recording material and a thermosensitive recording paper having the thermosensitive recording layer.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Many scientific color-developing systems using energy such as heat, pressure, and light have been known. Among these, color-developing systems consisting of a two-component color-developing system consisting of a leuco dye, which is a dye precursor, and a color developer that develops color upon 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 binders, sensitizers, fillers, and lubricants, and coating the resulting liquid onto paper, film, synthetic paper, etc. Heating melts one or both of the leuco dye and the color developer, and the resulting chemical reaction upon contact results in a colored record (print). 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 advantages: (1) it does not make noise during recording, (2) it does not require development or fixing, (3) it is maintenance-free, and (4) the equipment is relatively inexpensive. Therefore, it is widely used in the fields of facsimile, computer output, printers for calculators and the like, recorders for medical measurement, automatic ticket vending machines, thermal recording labels, etc.

[0003] In recent years, the use of recording materials containing leuco dyes and color developers has expanded by utilizing the reversible reaction between the coloring matter and the leuco dye, and these materials are used as temperature-indicating materials in the fields of food and beverages, and as color-changing materials in the fields of toys and writing implements, etc. As the range of uses expands and the environments in which they are used become more diverse, 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.

[0004] Generally, color developers containing phenolic hydroxyl groups have high color-developing ability. Among these, many bisphenol-based compounds have been reported due to their high color density, including 2,2-bis(4-hydroxyphenylpropane) (bisphenol A) (Patent Document 1) and 4,4'-dihydroxydiphenyl sulfone (bisphenol S) (Patent Document 2). However, the use of phenolic compounds such as bisphenol A has been criticized due to endocrine problems, and non-phenolic color developers that do not contain phenol structures are desired. Examples of non-phenolic color developers include diphenylurea-based color developers described in Patent Documents 3 and 4. However, the diphenylurea-based color developers described in these documents have the disadvantage of being less thermally stable than phenolic color developers, resulting in color fading and loss even after a relatively short exposure to heat, thereby limiting their potential for wider use. In addition, sulfonylurea-based color developers described in Patent Documents 5 and 6 have been reported. However, there is a strong demand for recording materials that offer a good balance of color development, thermal stability, and alcohol resistance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent 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. 8-059603 [Patent Document 5] Patent Publication No. 2023-66217 [Patent Document 6] Japanese Patent Application Publication No. 7-257033 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a recording material in which the printed portion has excellent heat stability and alcohol resistance. [Means for solving the problem]

[0007] As a result of extensive research into achieving the above object, the present inventors have found that the above problems can be solved by using a recording material containing a compound having a specific structure as a color developer, and have thus completed the present invention. That is, the present invention relates to the following [1] to [8]. [1] The following general formula (1) [ka] (In formula (1), X represents a halogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms. R 1 represents a straight or branched chain alkyl group having 7 to 12 carbon atoms. A compound represented by the formula: [2] The compound according to the above [1], wherein in the above formula (1), X is a halogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. [3] The compound according to the above [1], wherein X in the above formula (1) is a methyl group. [4] A color developer containing the compound according to any one of [1] to [3] above. [5] A recording material containing the developer described in [4] above. [6] A heat-sensitive recording layer comprising the recording material described in [5] above. [7] A thermal recording paper having the thermal recording layer described in [6] above. [8] An ink containing the recording material described in [4] above. [Effects of the Invention]

[0008] The novel compound represented by general formula (1) can be used as a color developer to provide a recording material in which the printed portion exhibits high thermal stability and alcohol resistance. DETAILED DESCRIPTION OF THE INVENTION

[0009] The compound of the present invention is represented by the above general formula (1).

[0010] In formula (1), X represents a halogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms. 1 represents a straight or branched chain alkyl group having 7 to 12 carbon atoms. Examples of the halogen atom represented by X in formula (1) include a fluorine atom, a chlorine atom, and a bromine atom, with a fluorine atom and a chlorine atom being preferred.

[0011] The alkyl group represented by X in formula (1) may be either a straight chain or a branched chain as long as it has 1 to 8 carbon atoms, and is preferably a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isopropyl group, an isobutyl group, a sec-butyl group, or a t-butyl group having 1 to 4 carbon atoms, and more preferably a straight chain or branched chain alkyl group having 1 to 3 carbon atoms. In this specification, for example, "a straight or branched alkyl group having 1 to 8 carbon atoms" does not include the non-existent "branched alkyl group having 1 or 2 carbon atoms."

[0012] R in Equation (1) 1 The linear or branched alkyl group represented by is not particularly limited as long as it has 7 to 12 carbon atoms, and examples thereof include linear alkyl groups such as n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, and n-dodecyl groups, and branched alkyl groups such as methylheptyl, dimethylheptyl, and ethylheptyl groups.

[0013] In formula (1), X is a linear or branched alkyl group having 1 to 4 carbon atoms, and R 1is particularly preferably a linear alkyl group having 7 or 12 carbon atoms, X is an alkyl group having 1 carbon atom, and R 1 is most preferably a straight chain alkyl group having 7 or 8 carbon atoms.

[0014] Next, the method 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 known production flow shown below. 1 are X and R in formula (1). 1 This is synonymous with "preferred" as well.

[0015] [ka]

[0016] The compound represented by the above general formula (1) can be produced by reacting an isocyanate represented by formula (A) with an amine represented by formula (B) in the presence or absence of a base.

[0017] Examples of the base that can be used if desired in the above production method include inorganic bases such as sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, and cesium carbonate; and organic bases such as triethylamine, diisopropylethylamine, and pyridine. The amount of these bases used is preferably 1 to 3 times the number of moles of the isocyanates represented by formula (A).

[0018] The solvent used in the above production method is not particularly limited as long as it does not affect the reaction, and examples thereof include 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, which may be used alone or in combination.

[0019] In the above production method, 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.

[0020] The recording material of the present invention contains the compound of the present invention as a developer, 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. In a preferred embodiment, the content of each component in the recording material of the present invention is, in terms of mass ratio in the recording material, 1 to 50% by mass, more preferably 5 to 30% by mass, when a color-forming compound is contained; 1 to 70% by mass, more preferably 5 to 50% by mass, when the compound of the present invention is used as a color developer; 1 to 80% by mass when a sensitizer is contained; and 1 to 90% by mass when a binder is contained. Furthermore, the content of optional components is preferably 30% by mass or less for a storage stability improver, preferably 80% by mass or less for a filler, and preferably 30% by mass or less for other additives (lubricants, surfactants, antifoaming agents, UV absorbers, etc.).

[0021] Furthermore, it is more preferable to use the compound of the present invention in an amount of 0.5 to 20 parts by mass, and particularly preferable to use the compound of the present invention in an amount of 1 to 5 parts by mass, per part by mass of the color-forming compound. Note that the recording material of the present invention may contain a color developer other than the compound of the present invention in combination, provided that the effect of the present invention is not impaired.

[0022] The color-forming compound used in the recording material of the present invention is not particularly limited as long as it is one that is generally used in pressure-sensitive recording paper or heat-sensitive recording paper. Examples of the color-forming 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.

[0023] Specific examples of fluoran 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, 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-pyro Examples thereof 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.

[0024] 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). 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.

[0025] Specific examples of spiro compounds include 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-propylspirobenzopyran, 3-methylnaphtho-(3-methoxybenzo)spiropyran, and 1,3,3-trimethyl-6-nitro-8'-methoxyspiro(indoline-2,2'-benzopyran). 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 leucomethylene blue, p-nitrobenzoyl leucomethylene blue, and the like.

[0026] Specific examples of lactam compounds include rhodamine B anilinolactam and rhodamine B p-chloroanilinolactam. Specific examples of fluorene 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.

[0027] 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.

[0028] Examples of waxes include Japan 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, methylolbehenic acid amide, methylenebisstearic acid amide, and ethylenebisstearic acid amide; and examples of higher fatty acid anilides include stearic acid anilide and linoleic acid. anilides, etc.; naphthalene derivatives such as 1-benzyloxynaphthalene, 2-benzyloxynaphthalene, 1-hydroxynaphthoic acid phenyl ester, and 2,6-diisopropylnaphthalene; aromatic ethers such as 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 such as p-hydroxybenzoic acid benzyl ester, p-benzyloxybenzoic acid benzyl ester, and terephthalic acid dibenzyl ester; aromatic sulfonic acid ester derivatives such as p-toluenesulfonic acid phenyl ester, phenylmesitylenesulfonate, 4-methylphenylmesitylenesulfonate, and 4-tolylmesitylenesulfonate; 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;

[0029] Specific examples of binders preferably used in the heat-sensitive material of the present invention include water-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, polyvinyl pyrrolidone, 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, or (meth)acrylates. ) acrylate copolymers, styrene / (meth)acrylate copolymers, polyurethanes, polyester polyurethanes, polyether polyurethanes, polyvinyl acetate, ethylene / vinyl acetate copolymers, polyvinyl chloride, vinyl chloride / vinyl acetate copolymers, polyvinylidene chloride, polystyrene, styrene / butadiene (SB) copolymers, carboxylated styrene / butadiene (SB) copolymers, styrene / butadiene / acrylic acid copolymers, acrylonitrile / butadiene (NB) copolymers, carboxylated acrylonitrile / butadiene (NB) copolymers, and hydrophobic polymer emulsions such as composite particles of colloidal silica and (meth)acrylic resin.

[0030] 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, 1,1-bis(p-hydroxyphenyl)cyclohexane, 4,4′-thiobisphenol, 4,4′-cyclohexylidenediphenol, 2,2′-bis(2,5-dibromo-4-hydroxyphenyl)propane, 4,4′-isopropylidenebis(2-t-butylphenol), 2,2′-methylenebis(4-chlorophenol), 4,4′-dihydroxydiphenylsulfone, 4-hydroxyphenylsulfone ... phenolic compounds such as 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, and 2,4-dihydroxy-2'-methoxybenzanilide; aromatic carboxylic acid derivatives such as benzyl p-hydroxybenzoate, 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; and aromatic carboxylic acids or polyvalent metal salts thereof.

[0031] 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'-hydroxybenzoyl)methyl]-2-methyl-4-methyl-1-methyl-2-methyl-1 ... 4-[α',α'-bis(4'-hydroxyphenyl)ethyl]benzene, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, tris(2,6-dimethyl-4-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 resin, phenol novolac epoxy resin, and bisphenol A epoxy resin; 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]- butyl)benzene, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, tris(2,6-dimethyl-4-tert-butyl-3-hydroxybenzyl)isocyanurate, 4,4'-thiobis(3-methylphenol), 4,4'-dihydroxy-3,3',5,5'-tetrabromodiphenyl sulfone, 4,4'-dihydroxy-3,3',5,5'-tetramethyldiphenyl 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'-diglycidyloxydiphenyl sulfone, 4-benzyloxy-4'-(2-methylglycidyloxy)diphenyl sulfone, diglycidyl terephthalate, cresol novolac epoxy Examples of the epoxy resin include epoxy compounds such as 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, bis(4-ethyleneiminocarbonylaminophenyl)methane, urea urethane compounds (such as Developer UU manufactured by Chemipro Chemical Co., Ltd.), and diphenyl sulfone-bridged compounds represented by the following formula (2) or mixtures thereof: where a is an integer from 0 to 6.

[0032] [ka]

[0033] 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.

[0034] 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 the thermal head, 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.

[0035] Next, the method for preparing the recording material and thermosensitive recording paper of the present invention will be described. The color developer represented by formula (1), 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 needed to prepare a dispersion (usually, when pulverization or dispersion is carried out wet, water is used as the medium). The respective dispersions are then mixed to prepare a coating solution for the recording material, and the coating solution is applied to 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 By applying the coating composition 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 and drying the coating composition, The term "thermosensitive recording paper" in this specification also includes a support other than paper on which a thermosensitive recording layer is provided.

[0036] 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) can be prepared, for example, by grinding and dispersing the components required for the intermediate layer or overcoat layer together with a binder or other additives used as needed to prepare a cloth solution, in the same manner as in the preparation of the coating solution for the recording material described above, and then dispersing the cloth solution to a dry weight of usually 0.1 to 10 g / m. 2 The coating may be formed by applying the coating to a thickness of about 1000 nm and drying it.

[0037] The coating liquid (dispersion) of the recording material of the present invention can also be incorporated into inks for general writing instruments or inkjet inks. For example, writing instrument inks 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, a rust inhibitor, a preservative, or an antibacterial agent, etc., as appropriate for the intended use, or an oil-based ink containing a main solvent such as polypropylene glycol, polybutylene glycol, or polyoxypropylene diglyceryl ether, a resin, a lubricant, a rust inhibitor, a preservative, or an antibacterial agent, etc., as appropriate for the intended use. [Example]

[0038] 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.

[0039] Example 1 (Synthesis of the color developer of the present invention) To 100.0 parts of tetrahydrofuran, 5.0 parts of n-octylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (b-1) and 3.7 parts of pyridine were added and stirred at 5°C. Next, 8.0 parts of p-toluenesulfonyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (a-1) was added dropwise, and the mixture was stirred at 5°C for 3 hours. After concentration using an evaporator, the mixture was dissolved in 200.0 parts of ethanol, and 100 parts of hexane was slowly added to form two layers, taking care not to mix with the ethanol layer. The mixture was left to stand at 3°C ​​for 14 hours, and the precipitate was filtered off, washed successively with hexane and 5% ethanol water, and dried to obtain 7.5 parts of a white solid of color developer 1 represented by the following formula (c-1).

[0040] [ka]

[0041] Example 2 (Synthesis of the color developer of the present invention) To 100.0 parts of tetrahydrofuran, 6.10 parts of 1-aminodecane (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (b-2) and 3.7 parts of pyridine were added and stirred at 5°C. Next, 8.0 parts of p-toluenesulfonyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (a-1) was added dropwise, and the mixture was stirred at 5°C for 3 hours. After concentration using an evaporator, the mixture was dissolved in 200.0 parts of ethanol, and 100 parts of hexane was slowly added to form two layers, taking care not to mix with the ethanol layer. The mixture was left to stand at 3°C ​​for 14 hours, and the precipitate was filtered off, washed successively with hexane and 5% ethanol water, and dried to obtain 7.1 parts of a white solid of color developer 2 represented by the following formula (c-2).

[0042] [ka]

[0043] Comparative Example 1 (Synthesis of Comparative Color Developer) To 100.0 parts of tetrahydrofuran, 5.00 parts of tetradecylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (b-3) and 2.2 parts of pyridine were added and stirred at 5°C. Next, 4.9 parts of p-toluenesulfonyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (a-1) was added dropwise, and the mixture was stirred at 5°C for 3 hours. After concentration using an evaporator, the mixture was dissolved in 200.0 parts of ethanol, and 100 parts of hexane was slowly added to form two layers, taking care not to mix with the ethanol layer. The mixture was left to stand at 3°C ​​for 14 hours, and the precipitate was filtered off, washed successively with hexane and 5% ethanol water, and dried to obtain 4.5 parts of a white solid of color developer 3 represented by the following formula (c-3).

[0044] [ka]

[0045] Examples 1 and 2 and Comparative Examples 1, 2 and 3 (Preparation of Coating Solution for Recording Material and Preparation of Thermosensitive Recording Paper Having a Thermosensitive 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 (c-1) obtained in Example 1, the compound represented by formula (c-2) obtained in Example 2, the compound represented by formula (c-3) obtained in Comparative Example 1, tolbutamide (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (X) and described in Patent Document 5 as Comparative Example 2, 1-(4-chlorophenylsulfonyl)-3-propylurea (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (Y) and described in Patent Document 5 as Comparative Example 3, and other components were blended in the compositions shown in Table 1, and then milled and dispersed for 1 hour to prepare solutions [A] (A-1 to A-5).

[0046] [ka]

[0047] [Table 1]

[0048] The "other ingredients" used in solution [A] are as follows: PVA aqueous solution: 20% aqueous solution of Gohsenex L-3266 (Mitsubishi Chemical Corporation) SF104: Surfynol 104PG-50 (50% propylene glycol solution of Surfynol 104 manufactured by Nissin Chemical Industry Co., Ltd.)

[0049] (Adjustment of [B] solution) 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-forming 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 (Nippon Soda Co., Ltd.) PVA aqueous solution: 15% aqueous solution of Gohsenex L-3266 (Mitsubishi Chemical Corporation)

[0050] (Adjustment of coating liquid for recording material) The liquid [A], liquid [B] and other components obtained above were mixed in the composition shown in Table 2 to prepare a coating liquid for the recording material.

[0051] [Table 2]

[0052] 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, manufactured by Yabashi Industries Co., Ltd.) 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.)

[0053] Examples 1 and 2 and Comparative Examples 1, 2, and 3 (Preparation of Thermosensitive Recording Paper) The coating liquids for the recording materials obtained in Examples 1 and 2 and Comparative Examples 1, 2 and 3 were applied to a recording sheet having a basis weight of 50 g / m 2 Dry weight of 5g / m on wood-free paper 2 The thermal recording papers of the present invention and for comparison were prepared by coating and drying the respective coatings.

[0054] (Evaluation of color development of thermal recording paper) Using a Toyo Seiki Seisakusho thermal gradient tester (HG-100-2), printing was performed on each of the thermal recording papers obtained in Examples 1 and 2 and Comparative Examples 1, 2, and 3 by heat pressing at 100°C for 1 second at a pressure of 0.15 MPa. Using an X-Rite "eXact" colorimeter, the reflection density of the colored portion of the printed matter was measured under the following conditions: Illuminant C light source, Status A density standard, and a viewing angle of 2 degrees. The Dk value, which is the reflection optical density (OD), was calculated, and the color development was evaluated according to the following criteria. A higher Dk value indicates better color development. The results are shown in Table 3. Evaluation criteria ◎: Dk value is 0.15 or more ○: Dk value is 0.10 or more and less than 0.15 △: Dk value is 0.85 or more and less than 0.10 ×: Dk value is less than 0.85

[0055] (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 thermosensitive recording papers obtained in Examples 1 and 2 and Comparative Examples 1, 2, and 3 with a pulse width of 1.4 msec, and the printed matter was heated at 90°C for 60 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 an illuminant C light source, a status A density standard, 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, 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 80% or more 〇: Residual rate is 75% or more but less than 80% △: Residual rate is 70% or more but less than 75% ×: Residual rate is less than 70%

[0056] (Evaluation of alcohol 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 thermosensitive recording papers obtained in Examples 1 and 2 and Comparative Examples 1, 2, and 3 with a pulse width of 1.4 msec. The printouts were then left in a 20% ethanol aqueous solution for 30 minutes and dried at room temperature. Using a colorimeter manufactured by X-Rite, product name "eXact," the reflection density of the colored portion of the sample before and after leaving it in 20% ethanol 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. (Reflection density of colored area after alcohol test) / (Reflection density of colored area before alcohol test) x 100 The residual rate (%) of the colored area was calculated using the formula above, and the alcohol resistance was evaluated according to the following criteria. A higher residual rate indicates better heat resistance. The results are shown in Table 3. Evaluation criteria ◎: Residual rate is 70% or more 〇: Residual rate is 65% or more but less than 70% △: Residual rate is 60% or more but less than 65% ×: Residual rate is less than 60%

[0057] [Table 3]

[0058] From the results in Table 3 above, it can be seen that the thermal recording paper of the example, which uses a recording material containing a color developer of the specific structure of the present invention, achieved results of 0 or above in all items, and has a better balance of color development, heat resistance, and alcohol resistance in the printed area (color-developing area) than the thermal recording paper of the comparative example, which uses a recording material containing a color developer of the comparative example (the color developer described in Patent Documents 5 and 6).

Claims

1. The following general formula (1) 【Chemistry 1】 (In formula (1), X represents a halogen atom, a linear or branched alkyl group having 1 to 8 carbon atoms, or a linear or branched alkoxy group having 1 to 8 carbon atoms. R 1 represents a linear or branched alkyl group having 7 to 12 carbon atoms. A compound represented by the formula:

2. 2. The compound according to claim 1, wherein in the formula (1), X is a halogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms.

3. The compound according to claim 1, wherein X in formula (1) is a methyl group.

4. A color developer containing the compound according to claim 1 .

5. A recording material containing the color 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 5.

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