JPH03230991A - Recording material - Google Patents

Abstract

PURPOSE:To improve color forming properties, raw preservability and the stability of a developed color image, in a recording material utilizing the color development due to the contact of an electron donating leuco dye with an electron acceptive compound, by using a compound represented by formula (1) as the electron donating leuco dye. CONSTITUTION:In formula, Ar1 and Ar2 are an aryl group having an amine residue or a heterocyclic group, R1-R5 are a hydrogen atom or a monovalent group, R6 is an amino group which may have a substituent and mutually bonded to form an alicyclic 4-12 membered ring which may contain a hetero atom. As the electron acceptive compound developing a color upon contact with a leuco dye, a usual compound, for example, a phenol derivative, a salicylic acid derivative, a metal salt of aromatic carboxylic acid, acid clay, bentonite, a novolac resin, a metal treated novolac resin or a metal complex are used and may be used in combination.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a recording material, and particularly to a recording material in which a color-developing portion has absorption in the near-infrared region.

(Prior Art) Recording materials using electron-donating colorless dyes and electron-accepting compounds are already well known as pressure-sensitive paper, thermal paper, light-sensitive pressure-sensitive paper, electrically conductive thermal recording paper, thermal transfer paper, and the like. For example, British Patent No. 2140449, U.S. Patent No. 4480052, U.S. Pat.
For details, see No. 60-123557.

In recent years, optical character reading devices and barcode reading devices have become rapidly popular, and along with this, 700nm
There has been a strong demand for recording materials that have absorption in the near-infrared region of m or more.

Several proposals have been made as electron-donating colorless dyes that absorb in the near-infrared region.
-No. 199757, No. 61-284485, No. 59-
No. 448695, No. 51-121035, No. 5112
No. 1037 and No. 60-230890 are disclosed. However, no material has yet been obtained that has absorption in the near-infrared region and satisfies color development, shelf life, and stability of colored images.

The present inventors have discovered that specific compounds are effective in improving these properties.

(Objective of the Invention) Therefore, the object of the present invention is to have a color-forming part that has absorption in the near-infrared region, and has good color-forming properties, shelf life, and stability of colored images, and also meets other necessary conditions. The objective is to provide satisfactory recording materials.

(Structure of the Invention) An object of the present invention is to provide a recording material that utilizes color development through contact between an electron-donating colorless dye and an electron-accepting compound, in which the electron-donating colorless dye is represented by the following general formula (I). This was achieved using a recording material characterized by the use of a compound that

In the above formula, A r 2 and A r 2 are an aryl group or a heterocyclic group having an amine residue, R1-R5 are a hydrogen atom or a divalent group, and R6 is an amino group which may have a substituent. represents. Further, R1 to R5 are connected to each other to represent an alicyclic 4- to 12-membered ring which may contain a petro atom.

In addition, the aryl group and the heterocyclic group further include an alkyl group, an alkoxy group, an aryloxy group, a halogen atom, a nitro group,
It may have a substituent such as a cyano group, a substituted carbamoyl group, a substituted sulfamoyl group, a substituted amine group, a substituted oxycarbonyl group, a substituted oxysulfonyl group, an alkylthio group, an arylsulfonyl group, or an aryl group.

Ar1 Ar2, R1-R6 substituents have 25 carbon atoms
Below, 15 or less is particularly preferable.

Among Ar+ Ar2, from the viewpoint of synthetic handling, phenyl groups, naphthyl groups, or substituted indoles having amine residues, carbazole, indolenine, quinoline, etc. are preferable. In particular, from the viewpoint of coloring wavelength, a dialkylamino group, an alkylamine group, an amine group, an acylamino group, a diarylamino group, an arylalkylamino group, or an arylamino group is substituted at the para-position and/or ortho-position, more preferably at the para-position. Phenyl group and naphthyl group are preferred.

A more preferable compound of the present invention is represented by the general formula (I1), in which R1 to R6 have the above-mentioned meanings, R7 to RIO are hydrogen atoms,
Alkyl group, aryl group, RR12 is hydrogen atom, alkyl group, aryl group, alkoxy group, aryloxy group, cyano group, nitro group, substituted amine group, halogen atom,
an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group; m and n represent integers of 1 to 4;

Note that the alkyl group represents a saturated, unsaturated, or cycloalkyl group, and these are substituted with an aryl group, an alkoxy group, an aryloxy group, an acyloxy group, a halogen atom, an acylamino group, an aminocarbonyl group, a hydroxy group, or a cyan group. It may have a group.

More preferably, R4-R6 are a hydrogen atom, an alkyl group,
Alkoxy group, alkylthio group, alkoxycarbonyl group, aryl group, aryloxy group, arylthio group,
Aryloxycarbonyl group, cyano group, R6 is -
N R13R14 [R13, R1+ are hydrogen atoms, alkyl groups, aryl groups, heterocyclic groups, 5O2RI5, COR1
6 (R45 and R16 represent an alkyl group, an aryl group, or a heterocyclic group).

RI3, R, 4 are connected to each other and represent a 4- to 12-membered ring structure which may contain a petro atom], R7 to RIo
represents a hydrogen atom, an alkyl group, an aryl group, R11, R1
2 is a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a cyano group, a nitro group, a substituted amino group, a haloken atom, an alkoxycarbonyl group, an aryloxycarbonyl group, an acyloxy group, and m and n are from 1 to Represents an integer of 4.

More specifically, among the substituents represented by R1-R5, hydrogen atoms, alkyl groups having 1 to 18 carbon atoms, alkoxy groups, alkylthio groups, alkoxycarbonyl groups, aryl groups having 6 to 12 carbon atoms, aryl An oxy group, an arylthio group, an aryloxycarbonyl group or a cyan group is preferred.

R1-R5 are hydrogen atoms, methyl groups, ethyl groups,
Propyl group, butyl group, amyl group, hexyl group, octyl group, octadecyl group, methoxypropyl group, ethoxypropyl group, phenoxyethyl group, cyclopentyl group,
Examples include cyclohexyl group, allyl group, benzyl group, phenethyl group, phenyl group, cyan group, methoxycarbonyl group, ethoxysulfonyl group, and methylthio group.

Furthermore, R5-R6 may be linked to each other to form an alicyclic 4- to 12-membered ring structure which may contain a hetero atom, and it is particularly preferable to form a 5- to 8-membered ring structure. Furthermore, this ring may have a substituent such as an alkyl group or an alkoxy group. In particular, it is preferable that R7 and R4 are connected.

Among the substituents represented by R6, those having 20 or less carbon atoms
-N R+3R14 [R13, R1,4 are hydrogen atoms, alkyl groups, aryl groups, heterocyclic groups, 5O2R15, CO
R+a (R+s, RI6 represents an alkyl group, an aryl group, or a heterocyclic group). Further, R13 and R14 are preferably connected to each other to represent a 4- to 12-membered ring structure which may contain a hetero atom. Further, it is preferable that R13 and R11 are not hydrogen atoms at the same time.

As R6, anilino group, 2-chloroanilino group, 2
-methoxycarbonylanilino group, 2-nitroanilino group, 2-methoxyanilino group, 3ethylanilino group, 4
-fluoroanilino group, 4-butoxyanilino group, 4-nitroanilino group, 2.4-dichloroanilino group, 2.5
-dimethylanilino group, β-naphthylamino group, N-methylanilino group, N-butylanilino group, pyridylamino group, quinolylamino group, cyclohexylamino group, indol-1-yl group, carbazol-1-yl group, succinylimide group, Acetylamino group, benzoylamino group, 2-methylbenzoylamino group, 4-methylbenzoylamino group, 4chlorobenzoylamino group, phenylsulfonylamino group, 4-methylphenylsulfonylamino group, 4-chlorophenylsulfonylamino group, pyrrolidino group, piperidino group, morpholino group, piperazino group, propylamino group, butylamino group, octylamino group, benzylamino group, phenethylamino group, octadecylamino group, dibutylamino group, dioctylamino group, dioctylamino group, ethylbutylamino group The basics are given.

Among the substituents represented by R7 to RIO, hydrogen atoms, alkyl groups having 1 to 18 carbon atoms, and 6 to 12 carbon atoms
An aryl group of is preferred.

R7 to RIO are hydrogen atom, methyl group, ethyl group, n-propyl group, 1so-propyl group, n-butyl group,
1so-butyl group, n-7mil group, 1sO-amyl group,
n-hexyl group, n-heptyl group, n-octyl group, 2
-ethylhexyl group, n-dodecyl group, n-octadecyl group, β-methoxyethyl group, β-ethoxyethyl group,
γ-methoxypropyl group, γ-ethoxypropyl group, β
-Phenoxyethyl group, β-cyanoethyl group, β-chloroethyl group, β-hydroxyethyl group, cyclopentyl group, cyclohexyl group, tetrahydrofurfuryl group, phenyl group, tolyl group, chlorophenyl group, methoxyphenyl group, pencil group, phenethyl group group, methylbenzyl group, chlorobenzyl group, and methoxybenzyl group.

Preferably, R7 to RIO are not hydrogen atoms at the same time.

R7 and R8, R9 and Rho are bonded to each other to form a ring which may contain a 5- to 8-membered heteroatom including the nitrogen atom to which they are bonded, such as pyrrolidine, piperidine, morpholine, and thiomorpholine. , piperazine, and caprolactam rings, and may further include a benzene ring to form indoline and julolidine rings.

Among the substituents represented by R11 and R12, a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group, a flukoxy rubber group having 2 to 12 carbon atoms, an acyloxy group, and an aryl group having 6 to 12 carbon atoms. group, aryloxy group, aryloxycarbonyl group having 7 to 12 carbon atoms, chlorine atom, bromine atom, fluorine atom, nitro group,
A cyan group, an amino group, a mono- or dialkylamino group having 1 to 12 carbon atoms, a mono- or diarylamino group having 6 to 18 carbon atoms, and a 7-syl amino group having 1 to 12 carbon atoms are preferred.

R11 and R12 are hydrogen atom, methyl group, ethyl group, propyl group, butyl group, octyl group, phenyl group, tolyl group, benzyl group, phenethyl group, methoxy group, ethoxy group, propoxy group, butoxy group, octyloxy group , benzyloxy group, phenoxyethoxy group, phenoxy group, chlorine atom, bromine atom, fluorine atom, nitro group, cyano group, dimethylamino group, diethylamino group, acetylamino group, acetyloxy group, and methoxycarbonyl group.

R11R12 is -NR from the viewpoint of coloring wavelength.

The meta position relative to -NR9R,o is preferred.

Specific examples of the color former of the present invention will be shown next, but the invention is not limited thereto.

(I) 8 Present invention (2) (3) (4) (5) (6) (7) (8) (9) (I0) (I1) (I2) (I3) (I4) (I5) (I 6) (I 8) In addition, these colorless dyes include well-known triphenylmethane phthalide compounds, fluoran compounds,
Recording materials can be produced in combination with various compounds such as phenothiazine compounds, indolylphthalide compounds, leucoauramine compounds, rhodamine lactam compounds, triphenylmethane compounds, triazene compounds, spiropyran compounds, and fluorene compounds. It can also be assembled.

In this case, it is preferable to use the above-mentioned colorless dye in an amount of 30% or more from the viewpoint of improving properties.

For example, specific examples of phthalides include U.S. Patent Reissue No. 23,024, U.S. Patent No. 3.491, M1, U.S. Pat. No. 3,624.107 and U.S. Pat. No. 3,627,78 for specific examples of fluorans.
No. 7, No. 3641.011, No. 3,462,828, No. 3.681,390, No. 3,920,510,
No. 3,959,571, specific examples of spiropyrans are US Pat. No. 3,971,808, and pyridine and pyrazine compounds are US Pat. No. 3,775.424, US Pat.
Specific examples of fluorene compounds are described in Japanese Patent Application No. 853,869, No. 4°246.318, and Japanese Patent Application No. 64-240989.

Examples of electron-accepting compounds that impart color upon contact with colorless dyes include common compounds such as phenol derivatives, salicylic acid derivatives, metal salts of aromatic carboxylic acids, acid clay, bentonite, novolac resins, metal-treated novolac resins, and metal complexes. are used, and these may also be used for internal purposes. Examples of these are JP-A-40-9309, JP-A-45-14039, JP-A-52-140483, JP-A-48-5+510, and JP-A-57-21088.
No. 6, JP-A-58-87089, JP-A-59-112
No. 86, JP-A-60-176795, JP-A-61-9
No. 5988, U.S. Pat. No. 3,767°449, U.S. Patent No. 4,2
No. 19,219, No. 4.269.893, No. 4,37
No. 4,671, No. 4687,869, etc. Particularly preferred are combinations with salicylic acid derivatives, phenol derivatives, metal complexes, acid clay, and bentonite.

When these are applied to recording materials, they are used in the form of fine dispersions or fine droplets, or in the form of films.

Furthermore, in this case, various additives well known in the fields of recording materials and polymer resins, such as pigments, waxes, antistatic agents, ultraviolet absorbers, antifoaming agents, conductive agents, and fluorescent agents, are used. Additives such as dyes and surfactants are used.

For use with pressure sensitive paper, U.S. Patent 2,505°470
No. 2,505,471, No. 2,505.489, No. 2,548, 3.66, No. 2712.507, No. 2,730,456, No. 2.730,457 issue,
It can take various forms as described in prior patents such as No. 3,103,404, No. 3,418,250, and No. 4,010,038. It most commonly consists of at least one pair of sheets containing separately an electron-donating colorless dye and an electron-accepting compound.

A method of manufacturing capsules is described in U.S. Pat. No. 2.800.
457, a method using coacervation of hydrophilic colloid vines described in British Patent No. 867.797, British Patent No. 950,443, British Patent No. 98
Examples include the interfacial polymerization method described in US Pat. No. 9,264 and US Pat.

The capsule wall material is preferably a synthetic resin wall material, for example, a polyurethane and/or polyurea material, or a melamine resin material.

In general, electron-donating colorless dyes are used alone or in combination as solvents (alkylated naphthalene, alkylated diphenyl, alkylated diphenylmethane, alkylated terphenyl, alkylated terphenyl, etc.).
synthetic oils such as chlorinated paraffin; vegetable oils such as cotton oil and castor oil; animal oils; mineral oils; or mixtures thereof).
and contain it in microcapsules, paper,
A coloring agent sheet is obtained by applying it to high-quality paper, plastic sheet, resin-coated paper, etc.

In addition to the electron-donating colorless dye, ultraviolet absorbers, antioxidants, and the like may be added as additives to the microcapsules. In particular, from the viewpoint of improving the stability of the electron-donating colorless dye in the capsule before use and the coloring of the capsule, benzotriazole-based ultraviolet absorbers, hindered amine-based antioxidants, hindered phenol-based antioxidants, aniline-based oxidants, etc. It is preferable to add an inhibitor, a quinoline antioxidant, etc.

In addition, an electron-accepting compound and optionally additives may be dispersed in a binder such as styrene-butadiene latex or polyvinyl alcohol, and used together with the pigment described below to produce paper, plastic sheets, resin-coated paper, etc. A developer sheet is obtained by coating the support.

The amounts of the electron-donating colorless dye and the electron-accepting compound to be used depend on the desired coating thickness, the form of the pressure-sensitive recording paper, the capsule manufacturing method, and other conditions, and may be appropriately selected depending on the conditions. It is easy for one skilled in the art to determine this amount to use.

When used for thermal paper, Japanese Patent Application Laid-open No. 61144989,
A form such as that described in Japanese Patent Application No. 62-244,883 can be used. Specifically, the electron-donating colorless dye and the electron-accepting compound are used after being pulverized and dispersed in a dispersion medium to a particle size of 10 μm or less, preferably 3 μm or less. As the dispersion medium, an aqueous polymer solution having a concentration of about 0.5 to 10% is generally used, and dispersion is carried out using a ball mill, sand mill, horizontal sand mill, attritor, colloidal mill, or the like.

The ratio of the electron-donating colorless dye to the electron-accepting compound used is preferably between 1=10 and 1:1 by weight, and particularly preferably between 1:5 and 2:3. At that time, it is preferable to use a thermofusible substance in combination. These are used in finely dispersed form at the same time as the electron-donating colorless dye or simultaneously with the electron-accepting compound. These are added at a weight ratio of 20% to 300%, particularly preferably 40% to 150%, based on the electron-accepting compound.

Additives may be added to the thus obtained coating liquid as necessary to meet various requirements. Examples of additives include dispersing oil-absorbing substances such as inorganic pigments and polyurea fillers in the binder to prevent the recording head from becoming dirty during recording, and also to improve the releasability of the head. For this purpose, fatty acids and metal soaps are added. Therefore, in addition to electron-donating colorless dyes and electron-accepting compounds that directly contribute to color development, thermofusible substances, pigments, waxes, antistatic agents, ultraviolet absorbers,
Additives such as antifoaming agents, conductive agents, fluorescent dyes, and surfactants are coated onto the support to form the recording material.

Furthermore, a protective layer may be provided on the surface of the heat-sensitive recording layer, if necessary. The protective layer may be laminated in two layers, if necessary. Further, a coating liquid similar to that of a protective layer may be applied to the back surface in order to correct the curl balance of the support or to improve chemical resistance from the back surface. An adhesive is applied to the back side, and an electron-donating colorless dye and an electron-accepting compound are usually dispersed in a binder and applied. Water-soluble binders are generally used, such as polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, epichlorohydrin-modified polyamide, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-maleic anhydride salicylic acid. Copolymers, polyacrylic acid, polyacrylic acid amide, methylol-modified polyacrylamide, starch derivatives, casein, gelatin, etc. can be used. Further, for the purpose of imparting water resistance to these binders, a water resistance agent may be added, or an emulsion of a hydrophobic polymer, specifically, styrene-butadiene rubber latex, acrylic resin emulsion, etc. may be added. The coating liquid is applied onto base paper, wood-free paper, synthetic paper, plastic sheet, resin-coated paper, or neutral paper.

Examples of thermofusible substances are disclosed in JP-A-58-57989 and JP-A-58-87094. Examples of such compounds include 2-benzyloxynaphthalene, 4-
Benzylbiphenyl, 1゜2-di-m-tolyloxyethane, 12-diphenoxyethane, 1,4-diphenoxybutane, bis-[β-(p-methoxyphenoxy)ethyl]ether, 1-phenoxy-2- p-Ethylphenoxyethane, 1-p-methoxyphenoxy2-phenoxypropane, 1-phenoxy-2p-methoxyphenoxypropane, 1.2-bis(p-methoxyphenoxy)propane, 1.3bis(p-methoxyphenoxy) Propane, 1p-methoxyphenoxy-2-〇-chlorophenoxyethane, 4-(p-methoxybenzylthio)anisole, 1-phenoxy-2-p-methoxyphenylthioethane, 1,2-bis(p-methoxyphenylthio) ) Ether compounds such as ethane, 1-p-methylphenoxy-2-p-methoxyphenylthioethane, 4-(4-chlorobenzyloxy)ethoxybenzene, stearamide, methylene bisstearamide, stearanilide, behen acid amide, stearic acid anilide,
Examples include stearyl urea.

Pigments include kaolin, calcined kaolin, talc, diatomaceous earth, calcium carbonate, aluminum hydroxide, magnesium hydroxide, zinc oxide, lithopone, amorphous silica, colloidal silica, calcined metal, silica, magnesium carbonate, titanium oxide, alumina. , barium carbonate, barium sulfate, mica, microballoons, urea-formalin fillers, polyester particles, cellulose fillers, etc. are used.

Examples of the metal soap include polyvalent metal salts of higher fatty acids, such as zinc stearate, aluminum stearate, calcium stearate, and zinc oleate.

Examples of waxes include paraffin wax, carboxy-modified paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, polystyrene wax, higher fatty acid esters, amides, and the like.

As the hindered phenol compound, a phenol derivative in which at least one of the 2nd and 6th positions is substituted with a branched alkyl group is preferred. For example, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1°1,3-tris(2-ethyl-4-
Hydroxy 5-t-butylphenyl)butane, ? ,
+, 3 tris(3,5-di-t-butyl-4-hydroxyphenyl)butane, 1,1,3-tris(2methyl-4-hydroxy-5-t-butylfer)propane, 4,4-butylidenebis (6-butyl-3-methylphenol, 44-thiobis(3-methyl-6-t-
butylphenol), 2,2-methylenebis(6-t-
butyl-4-methylphenol), 2,2-methylenebis(6t-butyl-4-ethylphenol), octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, l, 3. 5 trimethyl-2
, 46-tris(35-di-t-butyl-4-hydroxybenzyl)benzene, tetrakis[methylene-3-(3
5-dit](thyl-4-hydroxyphenyl)propinate comethane, 2,2,6.6-tetramethyl-4-
Examples include piperidinyl sebacate.

The amount of the hindered phenol compound to be used is preferably 1 to 200% by weight, more preferably 5 to 100% by weight, based on the electron accepting compound.

As ultraviolet absorbers, cinnamic acid derivatives, benzophenone-derived L-benzotriazolylphenol derivatives, etc.
For example, butyl α-cyano-β-fer cinnamate, 0
-benzotriazolylphenol, 0-benzotriazolyl-p-chlorophenol, 0-benzotriazolyl-p-methylphenol, 0-benzotriazolyl-2
, 4-di-t-butylphenol, and 0-penztriazolyl-2,4-di-t-octylphenol.

Water-resistant agents include water-soluble initial condensates such as N-methylol urea, N-methylol melamine, and urea-formalin, dialdehyde compounds such as glyoxal and glutaraldehyde, inorganic crosslinking agents such as boric acid and borax, and polyesters. Examples include blend heat treatment of acrylic acid, methyl vinyl ether-maleic acid copolymer, isobutylene-maleic anhydride copolymer, and the like.

Materials used for the protective layer include polyvinyl alcohol,
Carboxy-modified polyvinyl alcohol, vinyl acetate-acrylamide copolymer, silicon-modified polyvinyl alcohol, starch, modified starch, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, gelatins, gum arabic, casein, styrene-maleic acid copolymer hydrolyzate, Water-soluble polymers such as styrene-maleic acid copolymer half ester hydrolyzate, isobutylene-maleic anhydride copolymer hydrolyzate, polyacrylamide derivatives, polyvinylpyrrolidone, polystyrene sodium sulfonate, sodium alginate, and styrene-
Water-insoluble polymers such as butadiene rubber latex, acrylonitrile-phtadiene rubber latex, methyl acrylate-butadiene rubber latex, and vinyl acetate emulsion are used.

In addition, pigments, metal soaps, waxes, waterproofing agents, etc. may be added to the protective layer for the purpose of improving matching properties with the thermal head.

Further, when coating the protective layer on the thermosensitive coloring layer, a surfactant may be added in order to obtain a uniform protective layer. As the surfactant, a sulfosuccinic acid-based alkali metal salt, a fluorine-containing surfactant, etc. are used. Specifically, G (
Sodium salts or ammonium salts such as n-hexyl)sulfosuccinic acid and di(2-ethylhexyl)sulfosuccinic acid are preferred, but anionic surfactants are effective.

The electrically conductive thermal paper is manufactured, for example, by the method described in JP-A-49-14344 and JP-A-50-48930. Generally, a coating liquid containing a conductive substance, an electron-donating colorless dye, and an electron-accepting compound dispersed together with a binder is applied to a support such as paper, or a conductive substance is applied to the support to form a conductive layer. The electrically conductive thermal paper is manufactured by applying a coating liquid in which an electron-donating colorless dye, an electron-accepting compound, and a binder are dispersed thereon. Note that the sensitivity can also be improved by using the above-mentioned thermofusible substance in combination.

The photosensitive pressure sensitive paper is manufactured, for example, by the method described in JP-A-57-179836. In general, photopolymerization initiators such as silver iobromide, silver bromide, silver behenate, Michler's ketone, benzoin derivatives, and benzophenone derivatives 1 and crosslinking agents such as polyfunctional monomers such as polyallyl compounds, poly(meth)acrylates, and poly(meth)acrylamides The electron-donating colorless dye and, if necessary, a solvent are encapsulated in a synthetic resin capsule such as polyether urethane or polyurea. After imagewise exposure, the unexposed area is colored by contacting with an electron-accepting compound using an electron-donating colorless dye.

The electron-donating colorless dye according to the present invention has the following general formula (I
Using known methods such as British Patent No. 2,101,648 and Japanese Patent Publication No. 60-679 using ll) and (I) as raw materials,
No. 4, JP-A-48-729, JP-A-63-20855
8. It can be easily obtained by referring to the method disclosed in JP-A No. 60-231766.

In the above formula, R1 to R5, Ar7, Ar2 have the above-mentioned meanings,
- represents an anion necessary to form a dye, such as C1, Br CIO, -P F , -B F ,
-, etc.

(Synthesis Example 1) The compound of Example (I1) was added to a three-necked flask equipped with a stirrer, 1 mmol of sodium hydride, and 40 n of tetrahydrofuran! Weigh out and add 10.5 mmol of piperidine dropwise while stirring. After stirring at room temperature for 5 minutes, 10 mmol was gradually added, and the mixture was further stirred at room temperature for 4 hours. The reaction mixture was poured into water, and the target product was pale yellowish white crystals (melting point 99-101
°C).

(Synthesis Example 2) Compound of Specific Example (I5) Weighed 11 mmol of sodium hydride and 40 mg of tetrahydrofuran into a three-necked flask equipped with a stirrer, and while stirring, prepared methyl anthranilate.
o. Add 5 mmol dropwise. After stirring at room temperature for 5 minutes, 10 mmol was gradually added, and the mixture was further stirred at 40°C for 1 hour. The reaction mixture was poured into water to obtain the desired product as pale yellow crystals (melting point 156-8°C).

(Examples of the Invention) Examples are shown below, but the present invention is not limited thereto. % represents weight % unless otherwise specified.

(Example 1) The compound of specific example (I1), bisphenol A which is an electron-accepting compound, and 4-(4-chlorobenzyloxy)ethoxybenzene which is a thermofusible substance, each 209 to 100
9 5% polyvinyl alcohol (Kuraray PVA10'5
) Each dispersion was obtained by dispersing with an aqueous solution in a ball mill for one day and having a volume average particle size of 1.5 μm or less. Calcium carbonate 809 is also added to sodium hexametaphosphate.
Disperse with a homogenizer together with 5% solution 1609,
A pigment dispersion was obtained.

The dispersions prepared as described above are mixed in a ratio of 59 electron-donating colorless dye dispersions, 109 electron-accepting compound dispersions, 109 thermofusible substance dispersions, and 159 pigment dispersions,
Furthermore, emulsion 39 of 21% zinc stearate was added to obtain a heat-sensitive coating liquid.

This coating liquid was applied to high-quality paper using a coating bar so that the dry weight of the coating layer was 5 g/m2, and the temperature was 50°C.
After drying for 1 minute, a super calender was applied to obtain thermal recording paper.

The obtained thermal recording paper was free from fog during raw storage and had excellent stability over time.

Thermal recording paper is heated using a Kyocera Corporation type thermal head (KLT-
2+ 6-8MPDI) and 100kg just before the head
In a thermal printing experiment equipment with a pressure roll of /cn¥,
When printing was performed with a pulse width of 1.0 while using a pressure roll under conditions of a head voltage of 2.4 V and a pulse cycle of I Oms, a green-blue image was obtained. This colored image had absorption in the near-infrared region. Moreover, the obtained colored image showed good resistance to chemicals, sunlight, etc.

(Examples 2 to 4) In place of the electron-donating colorless dye and electron-accepting compound of Example 1, the following were used, respectively. A coated paper was obtained in the same manner as in Example 1 in other respects.

Example 2 Electron-donating colorless dye: Compound 109.2 of specific example (I)
-anilino-3-methyl-6-N,N dibutylaminofluorane 109 Electron-accepting compound: 5 g of bis(4-hydroxyphenyl) sulfone, benzimidazole complex of rhodan zinc 15
9 Example 3 Electron-donating colorless dye: Compound 109.2 of specific example (2)
-Methyl-6-(4-(N-(4-N.

N-dimethylaminophenyl)amino)anilino)fluorane 109 Electron-accepting compound = 1.1-bis(4-hydroxyphenyl)cyclohexane 89.4-β-p methoxyphenoxyethoxysalicylate zinc zinc 89 Danzinc 1-phenyl- 2,3-Dimethyl-3-pyrazolin-5-one complex 49 Example 4 Electron-donating colorless dye: Compound 109 of Specific Example (I5).
2-7 Nilino 3-Methyl-6-N-ethyl-N-isoamylaminofluorane 69.36"-bisdiethylamino-5-diethylaminospiro(isobenzofuran-1,9'-fluorene)-3-one 49 Electron accepting Compounds: bisphenol A109, acetylacetone complex of molybdic acid 109 In all cases of Examples 2 to 4, the obtained colored images had absorption in the near-infrared region and had good resistance to chemicals, sunlight, etc. Indicated.

(Example 5) (I) Preparation of capsule sheet containing electron-donating colorless dye 5 parts of a partial sodium salt of polyvinylbenzenesulfonic acid (manufactured by National Starch Co., Ltd., VER5A, Tl2O3) is dissolved in 95 parts of hot water and then cooled. . A sodium hydroxide aqueous solution was added to this to adjust the pH to 4.0. On the other hand, 100 parts of diisopropylnaphthalene in which 3.5% of the compound of Example (I1) was dissolved was emulsified and dispersed in 100 parts of a 5% aqueous solution of a partial sodium salt of the polyvinylbenzenesulfonic acid to form particles with a diameter of 4.0μ. An emulsion was obtained.

Separately, 6 parts of melamine, 11 parts of a 37% by weight formaldehyde aqueous solution, and 30 parts of water were heated and stirred at 60°C, and after 30 minutes, a transparent aqueous solution of a melamine-formaldehyde prepolymer was obtained.

This aqueous solution was mixed with the above emulsion. While stirring, the pH was adjusted to 6.0 with a 2M phosphoric acid solution, the liquid temperature was raised to 65°C, and stirring was continued for 6 hours. This capsule liquid was cooled to room temperature and adjusted to pH 9.0 with an aqueous sodium hydroxide solution.

To this dispersion, 200 parts of a 10% by weight polyvinyl alcohol aqueous solution and 50 parts of starch particles were added and water was added to prepare a solution of a microcapsule dispersion with a solid content concentration of 20%.

This coating liquid was coated on a 50 g/m2 base paper using an air knife coater so that the solid branch was coated at 5 g/m2, and dried to obtain a capsule sheet containing an electron-donating colorless dye.

(2) Preparation of electron-accepting compound sheet 3.5-bis-α-methylbenzylsalicylic acid zinc salt 1
0 part was added to 20 parts of 1-isopropylphenyl-2-phenylethane and dissolved. This was mixed with 50 parts of a 2% polyvinyl alcohol aqueous solution and 0.1 part of a 1°% dodecylbenzenesulfonic acid triethanolamine salt aqueous solution and emulsified so that the average particle size was 3 μm.

Next, a dispersion consisting of 80 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 200 parts of water was mixed with the above emulsion and added as a binder to 100 parts of a 10% PVA aqueous solution and carboxylic acid. Modified SBR
10 parts of latex (as solid content) was added and water was added so that the solid content concentration was 20% to obtain a coating liquid (A).

Next, 10 parts of the electron-accepting compound, 20 parts of Jilton clay
A dispersion containing 60 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 2.0 parts of water was dispersed using a sand grinder so that the average particle size was 3 μm.

Add 16 parts of a 10% PVA aqueous solution and 1°% PVA to this dispersion.
100 parts of an aqueous solution and 10 parts (as solid content) of carboxy-modified SBR latex were added, and water was added to make the solid content concentration 20% to obtain a coating liquid (B).

Coating liquid (A) and coating liquid (B) were mixed 1:1 in terms of electron-accepting compound, and 5.0 g/m2 was applied to 50 g/m2 base paper.
The mixture was coated using an air knife coater so that a solid content of 100% was coated, and dried to obtain an electron-accepting compound sheet.

The surface of the microcapsule sheet containing an electron-donating colorless dye is
When the electron-accepting compound sheets were stacked and a load of 600 kg/cm was applied, each sheet quickly developed a green-blue color. This colored image had absorption in the near-infrared region. Moreover, the obtained colored image showed good resistance to chemicals, sunlight, etc.

(Example 6) In place of the electron-accepting compound sheet of Example 5, the following was used.

(2゛) Preparation of electron-accepting compound sheet Acidic clay 100
were dispersed in 400 parts of a 0.5% aqueous sodium hydroxide solution, and then 20 parts of styrene-butadiene copolymer latex (solid content) and 40 parts of a 10% starch aqueous solution were added, thoroughly stirred and mixed, and the electron accepting A compound coating solution was obtained.

The coating solution prepared in this way was applied to 50g/m2 base paper for 5 minutes.
．． It was coated using an air knife coater so that the solid content was 0 g/m' and dried to obtain an electron-accepting compound sheet.

On this electron-accepting compound sheet, the surface of the electron-donating colorless dye-containing microcapsule sheet of Example 5 was layered for 600 kg.
g/cn? When a load of This colored image had absorption in the near-infrared region. In addition, the color image obtained has a high color density,
It showed good resistance to chemicals and sunlight.

Claims (1)

[Scope of Claims] In a recording material that utilizes color development due to contact between an electron-donating colorless dye and an electron-accepting compound, a compound represented by the following general formula (I) is used as the electron-donating colorless dye. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼(I) In the above formula, Ar_1 and Ar_2 are aryl groups or heterocyclic groups having an amine residue, and R_1 to R_5 are hydrogen atoms or monovalent groups. , R_6 represents an amino group which may have a substituent. Further, R_1 to R_5 are connected to each other and represent an alicyclic 4- to 12-membered ring which may contain a hetero atom.