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. 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.

[0003] 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.

[0004] Generally, color developers having phenolic hydroxyl groups 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 development density. However, the use of phenolic compounds such as bisphenol A is problematic due to endocrine problems, and non-phenolic color developers that do not contain phenol structures are in demand. As non-phenolic color developers, diphenylurea-based color developers shown in Patent Documents 3 and 4 have been reported. However, the diphenylurea-based color developers shown in these documents have a disadvantage that they have low thermal stability compared to phenolic color developers, and color development records fade and disappear when exposed to heat for a relatively short period of time, so that there are certain restrictions on the expansion of their applications. In addition, sulfonylurea-based color developers shown in Patent Documents 5 and 6 have been reported, but no compounds that meet 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Pat. No. 3,539,375 [Patent Document 2] Japanese Patent Publication No. 57-11088 [Patent Document 3] International Publication 2014 / 080615 [Patent Document 4] Japanese Patent Application Publication No. 8-059603 [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]

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

[0007] As a result of intensive research into achieving the above-mentioned object, the present inventors have found that the above-mentioned 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 is [1] The following general formula (1)

[0008] [ka]

[0009] (In formula (1), R 1 R represents a halogen atom or a linear or branched alkoxy group having 1 to 8 carbon atoms. 2 and R 3 one of which represents a hydrogen atom, and the other represents a branched alkyl group having 3 to 8 carbon atoms. [2] R 1 is a halogen atom or a linear or branched alkoxy group having 1 to 4 carbon atoms, and R 2 and R 3 the compound according to the above item [1], wherein one of the groups is a hydrogen atom and the other is a branched alkyl group having 3 or 4 carbon atoms; [3] R 1 is a halogen atom or a linear or branched alkoxy group having 1 to 3 carbon atoms, and R 2 and R 3 The compound according to the above item [2], wherein one of the formulas is a hydrogen atom and the other is a t-butyl group. [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

[0010] The novel compound represented by the general formula (1) can provide a recording material in which the printed portion exhibits high thermal stability as a developer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The compound of the present invention is represented by the above general formula (1).

[0012] In formula (1), R 1 R represents a halogen atom or a linear or branched alkoxy group having 1 to 8 carbon atoms. 2 and R 3 One of these represents a hydrogen atom, and the other represents a branched alkyl group having 3 to 8 carbon atoms. R in Equation (1) 1 Examples of the halogen atom represented by the formula (I) include a fluorine atom, a chlorine atom and a bromine atom, and a fluorine atom and a chlorine atom are preferred.

[0013] R in Equation (1) 1 The alkoxy group represented by may be either a straight chain or a branched chain as long as it has 1 to 8 carbon atoms, and is preferably a methoxy group, ethoxy group, n-propoxy group, n-butoxy group, isopropoxy group, isobutoxy group, sec-butoxy group or t-butoxy group having 1 to 4 carbon atoms, and more preferably a straight chain or branched chain alkoxy group having 1 to 3 carbon atoms. In addition, in this specification, for example, a "straight or branched alkoxy group having 1 to 8 carbon atoms" does not include a non-existent "branched alkoxy group having 1 or 2 carbon atoms."

[0014] R in Equation (1) 2 or R 3 The branched alkyl group represented by is not particularly limited as long as it has 3 to 8 carbon atoms, but isopropyl, isobutyl, sec-butyl and t-butyl, which have 3 or 4 carbon atoms, are preferred, and t-butyl is more preferred.

[0015] R in formula (1) 1 ~R 3 As for R 1 is a halogen atom or a linear or branched alkoxy group having 1 to 4 carbon atoms, and R 2 is a branched alkyl group having 3 or 4 carbon atoms, and R 3 is particularly preferably a hydrogen atom, and R 1 is a halogen atom or a linear or branched alkoxy group having 1 to 3 carbon atoms, and R 2 is a t-butyl group, and R 3 It is most preferred that is a hydrogen atom.

[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 the known production process shown below (R 3 The figure shows the manufacturing flow of the hydrogen atom developer, and the figure below shows R 2 It can be produced by a method similar to that of the production flow of the compound in which R is a hydrogen atom. 1 ~R 3 is R in formula (1). 1 ~R 3 is synonymous with.

[0017] [ka]

[0018] The compound represented by the above general formula (1-1) can be produced by reacting an isocyanate represented by formula (A) with an amine represented by formula (B-1) in the presence or absence of a base. The compound represented by the above general formula (1-2) can be produced by reacting an isocyanate represented by formula (A) with an amine represented by formula (B-2) in the presence or absence of a base.

[0019] 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 isocyanates represented by formula (A).

[0020] 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.

[0021] 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.

[0022] 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, as optional components, a storage stability improver, a filler and other additives.

[0023] The content of each component in the recording material of the present invention is, in terms of mass ratio in the recording material, preferably 1 to 50 mass %, more preferably 5 to 30 mass %, of the color-forming compound, preferably 1 to 70 mass %, more preferably 5 to 50 mass %, of the compound of the present invention as a color developer, preferably 1 to 80 mass %, of the sensitizer, preferably 1 to 90 mass %, of the binder. The content of optional components is preferably 30 mass % or less for the storage improver, preferably 80 mass % or less for the filler, and preferably 30 mass % or less for other additives (lubricants, surfactants, antifoaming agents, ultraviolet absorbers, etc.).

[0024] In a more preferred embodiment, 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 contain a developer other than the compound of the present invention insofar as the effect of the invention is not impaired.

[0025] The color-forming compound used in the recording material of the present invention is not particularly limited as long as it is one 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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;

[0032] 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.

[0033] 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. For example, 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'-cyclohexylidene diphenol, 2,2'-bis(2,5-dibromo-4-hydroxyphenyl)propane, 4,4'-isopropylidenebis(2-t-butylphenol), 2,2'-methylenebis(4-chlorophenol), 4,4'-dihydroxydiphenylsulfone, 4-hydroxy ... 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.

[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 (2) or mixtures thereof. In formula (2), 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, the method for preparing the recording material and thermal 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 ground 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 a dispersion (usually, when grinding or dispersing is performed in a wet manner, water is used as a medium), and then the respective dispersions are mixed to prepare a coating liquid 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 an amount of usually 1 to 20 g / m2 on a dry basis. 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, 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) may be 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 cloth solution, and then dispersing the cloth solution to a dry weight of usually 0.1 to 10 g / m. 2 The coating may be applied to a desired thickness and then dried.

[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 the color developer of the present invention) 14.2 parts of 4-tert-butylbenzenesulfamide (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (100-1) and 10.2 parts of 25% caustic soda were added to 200.0 parts of acetonitrile and stirred at room temperature. Then, 10.0 parts of 2-chlorophenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (100-2) was added dropwise and stirred at room temperature for 1 hour. After drying with an evaporator, the mixture was dispersed in 200.0 parts of butyl acetate, and separated three times with 200.0 parts of 0.3% hydrochloric acid to recover the oil layer. The oil layer was concentrated, and the precipitate was filtered off, washed with hexane and water in that order, and dried to obtain 13.6 parts of a white solid of developer 1 represented by the following formula (100-3).

[0043] [ka]

[0044] Example 2 (Synthesis of the color developer of the present invention) 5.0 parts of 4-tert-butylbenzenesulfamide (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (100-1) and 5.1 parts of 25% caustic soda were added to 100.0 parts of acetonitrile and stirred at room temperature. Then, 3.9 parts of 2-fluorophenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (101-2) were dropped and stirred at room temperature for 1 hour. After drying with an evaporator, the mixture was dispersed in 100.0 parts of butyl acetate, and separated three times with 100.0 parts of 0.3% hydrochloric acid to recover the oil layer. The oil layer was concentrated, and the precipitate was filtered off, washed with hexane and water in that order, and dried to obtain 7.6 parts of a white solid of developer 1 represented by the following formula (101-3).

[0045] [ka]

[0046] Example 3 (Synthesis of the color developer of the present invention) 5.0 parts of 4-tert-butylbenzenesulfamide (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (100-1) and 5.1 parts of 25% caustic soda were added to 100.0 parts of acetonitrile and stirred at room temperature. Then, 4.2 parts of 2-fluorophenyl isocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (102-2) were added dropwise and stirred at room temperature for 1 hour. After drying with an evaporator, the mixture was dispersed in 100.0 parts of butyl acetate, and separated three times with 100.0 parts of 0.3% hydrochloric acid to recover the oil layer. The oil layer was concentrated, and the precipitate was filtered off, washed with hexane and water in that order, and dried to obtain 8.6 parts of a white solid of color developer 1 represented by the following formula (102-3).

[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 (100-3) obtained in Example 1, the compound represented by formula (101-3) obtained in Example 2, the compound represented by formula (102-3) 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 130°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 110° C. for 20 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] [Table 3]

[0060] From the results in Table 3 above, it can be seen that the thermal recording paper of the embodiment, which uses a recording material containing a color developer of the specific structure of the present invention, has better heat resistance in the printed area (color-developed 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 3 and 4).

Claims

1. The following general formula (1) 【Chemistry 1】 (In formula (1), R １ R represents a halogen atom or a linear or branched alkoxy group having 1 to 8 carbon atoms. ２ and R ３ One of the groups represents a hydrogen atom, and the other represents a branched alkyl group having 3 to 8 carbon atoms. A compound represented by the formula:

2. R １ is a halogen atom or a linear or branched alkoxy group having 1 to 4 carbon atoms; R ２ and R ３ The compound according to claim 1, wherein one of said alkyl groups is a hydrogen atom and the other is a branched alkyl group having 3 or 4 carbon atoms.

3. R １ is a halogen atom or a linear or branched alkoxy group having 1 to 3 carbon atoms; R ２ and R ３ The compound according to claim 2, wherein one of said groups is a hydrogen atom and the other is a t-butyl group.

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.

Images