JPH02103175A - Recording material - Google Patents

Abstract

PURPOSE:To enance light fastness before use and characteristics of a preparation by using a specific compound as an electron donating leuco dye. CONSTITUTION:In a recording material utilizing color development due to the contact of an electron donating leuco dye with an electron acceptive compound, a compound represented by formula (wherein R1 is a 5-18C alkyl group, each of R2 and R3 is H, an alkyl group or an alkyl group, R4 is H or an alkyl group, R5 is H or an alkyl group and a ring A is a pyridine ring or a pyradine ring) is used as the electron donating leuco dye. As said leuco dye, there is 3-(1-n- amyl-2-methylindol-3-yl)-3-(1-methylpyrro-2-yl)-4- or -7-azaphthalide.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to recording materials, and more particularly to recording materials with improved light resistance before use.

(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. Patent No. 4436920, Japanese Patent Publication No. 6G-23992, Japanese Patent Publication No. 57
-179836, 60-123556, 60-12
I am familiar with 3557 etc.

In recent years, with the diversification of requirements for recording systems, research into multicolor recording has been intensively conducted. Among these, bisindolyl phthalide compounds are known as compounds that develop a red to magenta color. However, this compound has drawbacks. For example, 3.3-bis(l-n-octyl-2-methylindol-3-yl) phthalide develops quickly and exhibits a deep magenta color, but recording materials using this compound have poor light resistance before use. , the skin becomes yellow due to photodecomposition products.

Further, as a compound similar to the compound of general formula (1) of the present invention, 3-(1-ethyl-2-methylindole-3-
yl)-3-(1-methylpyrrol-2-yl)-7-
Although azaphthalide is known, it has poor solubility in organic solvents, and its suitability for liquid preparation becomes a problem when microencapsulated.

The present inventors have investigated the oil solubility, solubility in water, partition coefficient, pKa, polarity of substituent, position of substituent, crystallinity when mixed, for each of the electron donating colorless dye and the electron accepting compound. Focusing on characteristics such as changes in solubility, we have pursued the development of good materials for recording materials and recording materials.

(Object of the Invention) Therefore, the object of the present invention is to provide a recording material using a material that has good light resistance and liquid preparation suitability before use, and also satisfies other necessary conditions.

(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 (1). This was achieved by means of a recording material characterized by the use of the represented compounds.

In the above formula, R1 represents an alkyl group having 5 to 18 carbon atoms;
s, Rs represent a hydrogen atom, an alkyl group, or an aryl group, R4 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a nitro group, or a substituted amino group; R$ represents a hydrogen atom or an alkyl group; ring or pyrazine ring.

In addition, an alkyl group represents a saturated, unsaturated or cycloalkyl group, and these have a substituent such as an aryl group, an alkoxy group, an aryloxy group, an acyloxy group, a halogen atom, an acylamino group, an aminocarbonyl group, or a cyano group. You can leave it there.

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

The alkyl group represented by R1 in the above formula may be substituted with a halogen atom, an alkoxy group, an aryl group, an aryloxy group, an alkyl group, an acyl group, a cyano group, a hydroxy group, a furfuryl group, or the like.

More preferably, R1 is an alkyl group having 6 to 12 carbon atoms.

R1 is an n-amyl group, 1so-amyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, n-hexadecyl group, n- Examples include octadecyl group.

Among the 611 substituents represented by Ra and Rs in the above formula, hydrogen atoms, alkyl groups having 1 to 12 carbon atoms, and aryl groups having 6 to 12 carbon atoms are preferred.

Rs and R3 are hydrogen atom, methyl group, ethyl group, n
-butyl group, n-octyl group, phenyl group, p-methylphenyl group, etc.

Among the substituents represented by R1 in the above formula, hydrogen atoms, alkyl groups having 1 to 12 carbon atoms, and 1 to 12 carbon atoms.
An alkoxy group, a chlorine atom, a bromine atom, a nitro group, a mono- or dialkylamino group having 1 to 12 carbon atoms, and an acylamino group having 1 to 12 carbon atoms are preferred.

Among the substituents represented by R3 in the above formula, a hydrogen atom and an alkyl group having 1 to 12 carbon atoms are preferred.

Inside the ring is preferred. R@ is selected from the groups represented by R1. n represents an integer from 1 to 3.

Further into the circle is preferable from the viewpoint of synthetic handling and color development.

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

(1) 3-(1-n-amyl-2-methylindole-
3-yl)-3-(1-methylpyrrol-2-yl)-
4- or -7-azaphthalide (2) 3-(1-n-hexyl-2-methylindol-3-yl)-3-(1-
methylpyrrol-2-yl)-4- or -7-azaphthalide (3) 3-(1-n-octyl-2-methylindol-3-yl)-3-(1-methylpyrrol-2-yl)
-4= or -7-azaphthari(葡3-(1-(2-ethylhexyl)-2-methylindol-3-yl)-3-(1-methylpyrrole-2-
yl) l-4- or -7-azaphthalide 3- (1-1-dodecyl-2-phenylindole-
3-yl)-3-(1-methylpyrrol-2-yl)-
4- or -7-adeftado-3-(1-n-octadecyl indol-3-yl)
-3-(1-ethylpyrrol-2-yl)-4- or -
7-Azaphthalide 3- (1-n-octyl-2-methylindole-3
-yl)-3-(1-7enylpyrrol-2-yl)-
4- or -7-azaphthalide 3- (1-n-octyl-2-methylindole-'
3-yl)-3-(1-methylpyrrol-2-yl)-
4,7-diazaphthalide 3-(・1-n-hexyl-2
-methylindol-3-yl)-3-(1-n-butylpyrrol-2-yl)-4,7-diazaphthalide αrJ 3-(1-n-octyl-2-phenylindolumi-3-yl)- 3-(1-methylpyrrol-2-yl)-4- or -7-azaphthalide 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 40% 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 Specification No. 3,491.111, No. 3,491.112, and No. 3.491. .116 and 3.509.174
Specific examples of fluoranes are given in U.S. Patent Specification No. 3.6.
No. 24.107, No. 3.627.787, No. 3.
No. 641.011, No. 3.462.828, No. 3
, No. 681.390, No. 3,920.510, No. 3
No. 143.959,571, specific examples of spiropyrans are given in U.S. Patent No. 3,971.808, and pyridine and pyrazine compounds are given in U.S. Patent No. 3.115.
．． No. 424, No. 3.853゜869, No. 4.24
No. 6.318, specific examples of fluorene compounds are given in Japanese patent application No. 6.
No. 1-240989-, etc.

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 be used in combination. Examples of these are Special Publication No. 4G-9309, Special Publication No. 4
5-14039, JP 52-140483, JP 48-51510, JP 57-210886,
JP-A-58-87089, JP-A-59-11286, JP-A-60-176'1195, JP-A-61-95
No. 988, U.S. Patent Specification Contribution No. 3.767.449, U.S. Patent No. 4.219,219, U.S. Patent No. 4.269.893,
It is described in the same No. 4.374,671, the same No. 4.687.869, etc. In particular, combinations with salicylic acid derivatives and phenol derivatives are preferred.

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 No. 2,505.47
No. 0, No. 2,505.471, No. 2゜505.489
No. 2,548.366, No. 2.712.507, No. 2. '730.456, '2.730.457, '3,103.404, '3,418.250,
It can take various forms as described in prior patents such as 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 a hydrophilic colloid sol described in British Patent No. 2,800.458, British Patent No. 867.79II, British Patent No. 950.443, British Patent No. 950.443, British Patent No. 950.443, British Patent No.
Examples include interfacial polymerization methods described in US Pat. No. 89.264 and US Pat. No. 1.091.076, and the method described in US Pat.

The capsule wall material is preferably a synthetic resin-based wall material, for example, a polyurethane and/or polyurea-based material, or a melamine resin-based 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, etc.) are dissolved in microcapsules to produce paper, high-quality paper, plastic sheets, resin coatings, etc. A coloring agent sheet is obtained by applying it to ted paper, etc.

Since the color former of the present invention has good solubility in synthetic oils such as alkylated naphthalene, alkylated diphenyl, and alkylated diphenylalkane, it has the advantage that it can be used in combination with paraffinic oils having low solubility.

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, if necessary, additives may be dispersed in a binder such as styrene-butadiene latex or polyvinyl alcohol to produce paper, plastic sheets, resin-coated paper, etc., along with the pigments described below. A developer sheet is obtained by coating a support such as the following.

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, JP-A-62-144゜989
No. 62-244.883, etc. Specifically, the electron-donating colorless dye and the electron-accepting compound are 1Oμ or less in the dispersion medium.
It is preferably used after being pulverized and dispersed to a particle size of 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 1:1O and 1=1 by weight, and particularly preferably between 1:5 and 2=3. '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% or more and 300% or less, particularly preferably 40% or more and 150% or less, 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 in order to prevent the recording head from becoming dirty during recording, and also to improve releasability from the head. For this reason, fatty acids, metal soaps, etc. are added. Therefore, in general, in addition to electron-donating colorless dyes and electron-accepting compounds that directly contribute to color development, thermofusible substances, pigments, waxes, C antistatic agents, ultraviolet absorbers, antifoaming agents, conductive agents, and fluorescent Additives such as 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. Two or more protective layers may be laminated as 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 may be applied to the back side and a release paper may be further added to form a label.

Usually, the electron-donating colorless dye and the electron-accepting compound are dispersed in a binder and applied. Water-soluble binders are generally used, such as polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, epichlorohydrin-modified polyamide, and ethylene-
Examples include maleic anhydride copolymer, styrene-maleic anhydride copolymer, inbutylene-maleic anhydride copolymer, polyacrylic acid, polyacrylic acid amide, methylol-modified polyacrylamide, starch derivatives, casein, gelatin, etc. . 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 are phenethyl biphenyl, 2-benzyloxynaphthalene, 4-benzylbiphenyl, di-m-
) lyloxyethane, β-phenoxyethoxyanisole, 1-phenoxy-2-p-ethylphenoxyethane, bis-[β-(p-methoxyphenoxy)ethoxycomethane, 1-(2-methoxyphenoxy)-2-( 4
-ethyloxyphenoxy)ethane, 1,2-diphenoxyethane, 1,4-diphenoxybutane, bis-[β
-(p-methoxyphenoxy)ethyl ether, 1-
7 Dinoxy 2-p-chlorophenoxyethane, 1-(
4-methylphenoxy)-2-(4-fluorophenoxy)ethane, 1-7 dinoxy 2-p-methoxyf, nylthioethane, 1,2-bis(p-methoxyphenylthio)ethane, l-tolyloxy-2-p - Ether compounds such as methoxyphenylthioethane, stearamide, methylene bisstearamide, stearanilide, behenic acid amide, stearaniside, and stearyl urea.

Pigments include kaolin, calcined kaolin, talc, waxite, diatomaceous earth, calcium carbonate, aluminum hydroxide,
Magnesium hydroxide, zinc oxide, lithopone, amorphous silica, colloidal silica, calcined gypsum, silica, magnesium carbonate, titanium oxide, alumina, barium carbonate, barium sulfate, mica, microballoon, urea-formalin filler polyester particles, cellulose Fillers and the like are used.

Examples of metal soaps 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-)lis(2-methyl-4-hydroxy-5-t-butylphenyl)butane, l.

1.3-) Lis(2-ethyl-4-hydroxy-5-t
-butylphenyl)butane, l, 1,3-tris(3,
5-di-tert-butyl-4-hydroxyphenyl)butane, 1.1.3-)lis(2-methyl-4-hydroxy-
5-t-butylphenyl)furopane, 4,4-butylphenyl
Danbis (6-t-butyl-3-methylphenol, 4
．． 4-thiobis(3-methyl-6-t-butylphenol), 2.2-methylenebis(6-t-butyl-4-methylphenol), 2.2-methylenebis(6-t-butyl-4-ethylphenol) , octadecyl-3-(
3,5-di-t-butyl-4-hydroxyphenyl)propione-), 1.3.5-trimethyl-2,4,6-
) Lis(3,5-di-t-phthyl-4-hydroxybenzyl)benzene, Tetrakis[methylene-3-(3,5
-di-t-butyl-4-hydroxyphenyl)propinate comethane, 2.2,6.6-tetramethyl-4-piperidinyl sebacate, and the like.

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 derivatives, benzotriazolylphenol derivatives, etc.
For example, butyl α-cyano-β-phenylcinnamate, 0
-benzotriazolylphenol, o-benzotriazolyl-p-chlorophenol, O-benzotriazolyl-2,4-di-1-butylphenol, O-benzotriazolyl-2,4-di-t- and octylphenol.

Water-resistant agents include water-soluble initial condensates such as N-methylol urea, N-methylol melamine, and urea-formalin;
Blend heat treatment of dialdehyde compounds such as glyoxal and glutaraldehyde, inorganic crosslinking agents such as boric acid and borax, polyacrylic acid, methyl vinyl ether-maleic acid copolymer, inbutylene-maleic anhydride copolymer, etc. can be given.

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 hydration Decomposition product, styrene-maleic acid copolymer half ester hydrolyzate, inbutylene-maleic anhydride copolymer hydrolyzate, polyacrylamide derivative, polyvinylpyrrolidone, polystyrene sodium sulfonate,
Water-soluble polymers such as sodium alginate, and water-insoluble polymers such as styrene-butadiene rubber latex, acrylonitrile-butadiene 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 by the method described in, for example, Japanese Patent Application Laid-open No. 49-11344 and Japanese Patent Application Laid-Open No. 50-48930. Generally, a coating liquid in which a conductive substance, an electron-donating colorless dye, and an electron-accepting compound are 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, and then a conductive layer is formed on the support. 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. Note that the sensitivity can also be improved by using the thermofusible substance described above in combination.

The photosensitive pressure sensitive paper is manufactured by the method described in, for example, Japanese Patent Application Laid-open No. 179836/1983. In general, a photopolymerization initiator such as silver bromide, silver bromide, silver behenate, Michler's carbon dioxide, benzoin derivative, benzophenone derivative, etc. and a polyfunctional monomer such as polyallyl compound, poly(meth)l
A crosslinking agent such as acrylate or poly(meth)acrylamide is encapsulated in a synthetic resin capsule such as polyether urethane or polyurea together with an electron-donating colorless dye and, if necessary, a solvent. 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 is produced by known methods (for example, US Pat. No. 4,062,866, British Patent No. 1.422.096, etc.). For example, a corresponding indolecarbonyl-carboxypyridine derivative or an indolecarbonyl-carboxypyrazine derivative and a pyrrole derivative, or a corresponding pyrrolecarbonyl-carboxypyridine derivative or a pyrrolecarbonyl-carboxypyrazine derivative and an indole derivative are combined with acetic anhydride, sulfuric acid, oxy- The reaction is carried out in the presence of a condensing agent such as phosphorus chloride at a temperature of 40 to 130°C for 1 to 5 hours.

Synthesis Example 1 3-(1-n-year-old ctyl-2-methylindole-3-
yl)-3-(1-methylpyrrol-2-yl)-4-
2-(1-n-
Octyl-2-methylindol-3-yl)-3-carboxypyridine 0.1M, 1-methylpyrrole O,I
M, acetic anhydride 0.3M.

Weigh out 30 - of acetonitrile and stir at 65°C for 3 hours. The reaction mixture is poured into water and made alkaline with aqueous sodium hydroxide solution. This reaction mixture is purified using a silica gel column to obtain the desired product with a melting point of 99-100°C.

Synthesis Example 2 3-(1-n-year-old ctyl-2-methylindole-3-
yl)-3-(1-methylpyrrol-2-yl)-4,
7-diazaphthalide In a three-necked flask equipped with a stirrer, add 2-(1-n-
Octyl-2-methylindol-3-yl)-3-carboxypyrazine O, IM, 1-methylvirol 0.1
M, acetic anhydride 0.3M.

Measure 30 liters of acetonitrile and stir at 65°C for 3 hours. The reaction mixture is poured into water and made alkaline with aqueous sodium hydroxide solution. This reaction mixture is purified using a silica gel column to obtain the desired product with a melting point of 121-2°C.

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

(Examples 1 to 4) (1) 5 parts of a sodium salt of polyvinylbenzenesulfonic acid (manufactured by National Starch Co., Ltd., VER3A, Tl2O3) of a capsule sheet containing an electron-donating colorless dye is dissolved in 95 parts of hot water and then cooled. do. An aqueous sodium hydroxide solution was added to this to adjust the pH to 4°O. 100 parts of diisopropylnaphthalene in which 3.5% of the electron-donating colorless dye shown in the first method was dissolved was emulsified and dispersed in 100 parts of a 5% aqueous solution of IJium salt of the polyvinylbenzenesulfonic acid, and the diameter was 4.0 μm. An emulsion with a particle size of . Separately, 6 parts of melamine, 11 parts of 37% by weight formaldehyde aqueous solution
30 minutes after heating and stirring water 30B at 60° C., a transparent aqueous solution of a melamine formaldehyde initial polymer 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 temperature of the solution 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, 10% by weight polyvinyl alcohol aqueous solution 2001i1B and 50 parts of starch particles were added, and water was added to make the solid content concentration of the microcapsule dispersion 20.
A solution was prepared.

This coating liquid was coated on a 50 g/m'' base paper using an air knife coater so that the solid content was 5 g/m'' 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 10% dodecylbenzenesulfonic acid trienolamine salt aqueous solution, and emulsified so that the average particle size was 3.mu.m.

Next, 80 parts of calcium carbonate, 2 Ofl'lS of zinc oxide
A dispersion of sodium hexametaphosphate 18B and 200 parts of water was mixed with the above emulsion, and 100 parts of a 10% PVA aqueous solution and 10 parts of carboxy-modified SBR latex (as solid content) were added as a binder to form a solid. Water was added to give a concentration of 20% to obtain a coating liquid (A).

Next, a dispersion consisting of 10 parts of the color developer, 20 parts of Jilton clay, 60 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 200 parts of water was ground in a sand grinder until the average particle size was 3 μm. It was dispersed like that.

Add 16 parts of 10% PVA aqueous solution and 10% PVA to this dispersion.
100 parts of aqueous solution and carboxy-modified SBR latex 10111S (as solid content) were added until the solid content concentration was 2.
Water was added to the solution to give a coating liquid (B).

Coating liquid (A) and coating liquid (B) were mixed at a ratio of 1:1 in terms of developer, and coated on a 50 g/m2 base paper using an air knife coater so that a solid content of 5.0 g/m2 was applied. Apply at
It was dried to obtain a color developer sheet.

The surface of the microcapsule sheet containing an electron-donating colorless dye is
When the electron-accepting compound sheet was stacked and a load of 600 kg/m'' was applied, all of them quickly developed a magenta color.Before use, the surface of the microcapsule sheet containing an electron-donating colorless dye was exposed to a 3200 Glu x fluorescent lamp. Even after 16 hours of irradiation, no yellowing of the background was observed.Furthermore, the light fastness of the resulting image was excellent.

The coloring agent used is as follows.

Example 1 Compound Example 2 of Specific Example (3) Compound Example 3 of Specific Example (8) Compound Example 4 of Specific Example (5) Compound of Specific Example (lO) and 3.3-bis(1-n -octyl-2-methylindol-3-yl)phthalide 3
/l (weight ratio) mixture (Example 5) 20 g of the compound of specific example (1), 20 g of zinc 4-β-p-methoxyphenoxysalicylate, which is an electron-accepting compound.
1 2Gg of stearic acid amide, a heat-fusible substance, at 10
0g of 5% polyvinyl alcohol (Kuraray PVA105
) It was dispersed with an aqueous solution in a Pall mill overnight to give a volume average particle size of 3μ. On the other hand, calcined kaolin (Anisile
x-93) 80g to 0.5% of sodium hexametaphosphate
The mixture was dispersed using a homogenizer together with 160 g of the solution.

The dispersions dispersed as described above were mixed in a ratio of 5 g of the electron-donating colorless dye dispersion, log of the electron-accepting compound dispersion, 5 g of the stearamide dispersion, and 22 g of the calcined kaolin dispersion. emulsion 4
g and 5 g of a 2% aqueous solution of sodium (2-ethylhexyl)sulfosuccinate were added to obtain a coating liquid. This coating liquid was applied on high-quality paper with a basis weight of 50 g/m" in a dry coating amount of 6 g/m".
The mixture was applied with a wire bar so as to form snow, and calendering was performed to obtain coated paper.

The coated paper is Fujitsu Co., Ltd. Kosoku Facsi t QFF-
2000, a magenta image was obtained. This image has a high density, and the lightfastness of the image before use and
It had excellent heat resistance.

Claims (1)

[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, R_1 represents an alkyl group having 5 to 18 carbon atoms,
R_2 and R_3 are hydrogen atoms, alkyl groups, or aryl groups; R_4 is hydrogen atoms, alkyl groups, alkoxy groups, halogen atoms, nitro groups, or substituted amino groups; R_5 is hydrogen atoms or alkyl groups; Ring A is a pyridine ring. Or represents a pyrazine ring.