JPS63154389A - Recording material - Google Patents

Abstract

PURPOSE:To provide a recording material having favorable color forming properties, raw preservability and stability of developed color images and showing light absorption in near infrared region at a color-developed part, by incorporating a specified electron- donative colorless dye and an electron acceptive compound. CONSTITUTION:A recording material comprises an electron-donative colorless dye of general formula (I) and an electron-acceptive compound. The electron-acceptive compound is preferably one of compounds consisting of salicylic acid derivatives and metallic salts, particularly, a zinc salt. The recording material shows light absorption in near infrared region at a color-developed part, has a sufficient developed color density, with the color developed coloring matter being extremely stable, and is substantially free of discoloration or fading even under irradiation with light, heating or moistening for a long time, so that the recording material is particularly advantageous from the viewpoint of long-time preservation of records. When the recording material is almost used as a thermal recording material, the recording material is almost free of color development of an undeveloped part by a solvent or the like, and is free of discoloration or fading of the color-developed coloring matter due to an oil or fat, chemicals or the like. Therefore, the recording material has performance approximate to an ideal one.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a recording material, and in particular, a recording material having a color-forming portion absorbing light in the near-infrared region and having improved color-forming properties, shelf life, and stability of colored images. This invention relates to a recording material using an electron-donating colorless dye and an electron-accepting compound.

(Prior Art) Recording materials using an electron-donating colorless dye and an electron-accepting compound are already well known as pressure-sensitive paper, thermal paper, light-sensitive pressure-sensitive paper, current-carrying heat-sensitive recording paper, and the like.

For example, British patent - /≠O≠hirori, US patent Hiroμroo
js, same 1dl136?20. Tokuko Shoto o-xj,
PJ, 2, JP-A-77-/7-ri, rjj, 6o-t
2J! ! t, same 60-/23. Familiar with JJ-7 etc.

The performance that a recording material should have is (1) sufficient color density and color development sensitivity, (2) no fogging, (3) sufficient fastness of the color material after color development, (
4) Appropriate color hue and suitability for copying machines (5) S
/N ratio should be high, and (6) the color former should have sufficient chemical resistance, but currently there is no product that completely satisfies these requirements.

In particular, heat-sensitive recording materials have the disadvantage that fogging occurs due to solvents and the like, and the color formers are subject to discoloration and discoloration due to exposure to oils, fats, chemicals, etc. Therefore, water-based ink, oil-based ink, fluorescent paint, ink, adhesive,
When it comes into contact with stationery and office supplies such as glue and diazo developer, or cosmetics such as hand cream and emulsion, the white part becomes colored or the colored part changes color and fades, significantly reducing the product value. . The present inventors have investigated the oil solubility,
We are pursuing the development of good materials for recording materials and recording materials, focusing on characteristics such as solubility in water, partition coefficient, polarity of pKa substituents, position of substituents, and changes in crystalline solubility when mixed. Ta. Furthermore, in recent years, there has been a desire to develop recording materials that absorb in the near-infrared region.

(Objective of the Invention) Therefore, the object of the present invention is to provide a recording material which has good coloring properties, shelf life, and stability of colored images, and in which the coloring portion absorbs light in the near-infrared region.

(Structure of the Invention) The object of the present invention has been achieved by a recording material characterized by containing an electron-donating colorless dye represented by the following general formula (1) and an electron-accepting compound.

In general formula (1), R1, R2, R3, R4 are hydrogen atoms,
an alkyl group or an aryl group; R5, R6, and R7 represent a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a substituted amine group, or a halogen atom; and Ring A represents an aromatic ring containing a heteroatom.

R1 and R2, R3 and R4, and R5 and R6 may be bonded to each other to form a ring.

The aryl group represents a phenyl group, a naphthyl group, or a heteroaromatic ring group, and these include an alkyl group, an alkoxy group, an aryloxy group, a halogen atom, a nitro group, a cyano group, a substituted carbamoyl group, a substituted sulfamoyl group,
It may have a substituent such as a substituted amino group, a substituted oxycarminyl group, or a substituted oxysulfonyl group. Further, the alkyl group represents a saturated or unsaturated alkyl group or a cycloalkyl group, which may have a substituent such as an aryl group, an alkoxy group, an aryloxy group, a halogen atom, or a cyano group.

In the above formula, among the substituents represented by R1, R2, R3, and R4, even if the substituents include an alkyl group, an alkoxy group, a halogen-substituted alkyl group, an aryloxyalkyl group, and a substituent having 10 carbon atoms A phenyl group is preferable, and among the substituents represented by R5 and R6, a hydrogen atom, an alkyl group having a carbon atom number/-7, and a carbon atom number/~! An alkoxy group and a halogen atom are preferred. Also R5 and R6
may be combined to form an aromatic ring, and preferably a benzene ring is formed in %. Preferred examples of ring A include the following.

(R represents an alkyl group) Examples of these electron-donating colorless dyes are shown below.

These may be used alone, but they may be used in combination for one color tone adjustment and to prevent color fading of a colored image.

These electron-donating colorless dyes include other triphenylmethane phthalide compounds and fluoran compounds.

It may be used in combination with various compounds such as phenothiazine compounds, indolyl 7-thallide compounds, leucoauramine compounds, rhodamine lactam compounds, triphenylmethane compounds, triazene compounds, fluoran compounds, and spiropyran compounds. .

Specific examples of phthalides are listed in the U.S. Reissue Patent Specification Letter JJ,
No. 0244, U.S. Patent No. 3,4 cyi.

No. 111, same No. 3. Ko 5'/, / No. 12, No. 3
゜lri/, //bu issue and the same issue' v J OP +
/ No. 7μ, specific examples of fluorans are given in U.S. Patent Specification No. 3.4244.107, U.S. Patent No. 3,627,71/7, U.S. Pat. ≠62. No. t2 and No. 3,61/, J0, U.S. Patent Specification Tube 3. Octopus No. 0,310, U.S. patent specification cylinder 3. the law of nature! the law of nature,
No. 71, specific examples of spiropyrans can be found in U.S. Patent Specification 3. 7/, No. 101, pyridine-based and pyrazine-based color-forming compounds are described in U.S. Pat.

Jir No., specific examples of fluorene compounds are given in Japanese Patent Application No. 1987-
It is written in 2≠Ori No. etc.

Among the phenol derivatives according to the present invention, the following general formula CII
) to (V) are preferred.

In the above general formula (n), R1 and R2 may be the same or different, and include a hydrogen atom, an alkyl group, an alkoxy group,
R3 represents a hydrogen atom or a group represented by the following general formula (-1);

In the above formula (M), R1 and R2 represent the same as R1 and R2 in the above general formula (n), and R4 represents a monovalent group having a carbon atom number of /-/λ or SO2.

Among the compounds represented by the above general formula (II), R3=H
When R1 and R2 are a hydrogen atom or an alkoxycarbonyl group, and when R3 is a group represented by the general formula (■), R
4 is an alkylene group with 3 to 1 carbon atoms, the number of carbon atoms!
A cycloalkylene group having ~7 carbon atoms, an aralkylene group having r~/2 carbon atoms, and S02 are preferred.

In the above general formula, the alkyl group represents a saturated or unsaturated alkyl group or a cycloalkyl group, and these may have a substituent such as an aryl group, an alkoxy group, an aryloxy group, a halogen atom, or a cyano group. good. Some examples include ≠-phenylphenol, bisphenolsulfone, p-phenylsulfonylphenol, p-tolylsulfonylphenol, bis(3-vinyl-≠-hydroxyphenyl)sulfone, and 2-bis(J-vinyl-≠ -hydroxyphenyl)propane, bis-3-allyl-hydroxyphenyl sulfone, hexyl-hiro-, hydroxybenzoate, λ,2'-dihydroxybiphenyl, 2-bis(hiro-hydroxyphenyl)propane, p,l-isopyridene bis (co-methylphenol), /$/-bis(3-chloro-
H-hydroxyphenyl)cyclohexane, i,i-bis(j-chloro-≠-hydroxyphenyl)-coethylbutane, ≠,≠'-seca/dallyisooctylidene diphenol, ≠,≠'-5eC-butylidene Phenol, ≠-p-methylphenylphenol, ≠, μ′-yne is thilidenediphenol, ≠ 4! /-Methylcyclohexylidene diphenol, ≠, 4A'-dihydroxydiphenyl sulfide, /, Hiro-bis-(1,1/
-hydroxycumyl)benzene, l,3-bis-(+/
-hydroxycumyl)benzene, ≠rl -f obis(
j-tart-butyl-3-methylphenol), μ,
≠'-Dihydroxydiphenylsulfone hydroquinone monobenzyl ether, Hiro-hydroxybenzophenone, 22μm dihydroxybenzophenone, polyvinylbenzyloxyca/l/f, nylphenol, co, ≠,
3'-trihydroxybenzophenone, λ, 2', Hiro, l-tetrahydroxybenzophenone, Hiro-dimethyl hydroxyphthalate, ≠-methyl hydroxybenzoate,
2゜LL, l-)lyhydroxydiphenylsulfone,
/, yo-bis-p-hydroxyphenyl, /,
Otsu-bis-p-hydroxyphenoxyhexane, ≠-tolyl hydroxybenzoate, ≠-hydro*cybenzooctaic acid α-
Phenylbenzyl ester, phenylpropyl hydroxybenzoate, phenethyl ≠-hydroxybenzoate,
μm-hydroxybenzoic acid-p-chlorobenzyl, ≠-hydroxybenzoic acid-p-methoxybenzyl, Hiro-hydroxybenzoic acid benzyl ester, ≠-hydroxybenzoic acid-m-chlorobenzyl ester, Hiro-hydro*-cybenzoic acid β -7 enether ester, μm human (7x-2
/ , ≠′-dimethyldiphenyl sulfone, β-7enethyl orseinate, cinnamyl oreselinate, orselic acid-〇-chlorophenoxyethyl ester, 0
-ethylphenoxyethylorseinate, o-phenylphenoxyethylorce! 7), m-phenylphenoxyethyl orseinate, λ, Hiro-dihydroxybenzoic acid-β-3'-t-7'thyl-≠'-hydroxyphenoxyethyl ester, /-t--Aral-≠-D
-Hydroxyphenylsulfonyloxybenzene, ≠-
N-benzylsulfamoylphenol, 2. II-dihydroxybenzoic acid-p-methylbenzyl ester, co≠-dihydroxybenzoic acid-β-phenoxyethyl ester, 2. ! -dihydroxy-6-methylbenzoic acid benzyl ester, bis-μm hydroxyphenylacetate methyl, and the like.

In the above formula, R represents a hydrogen atom, an aryl group or an alkyl group, X represents an alkyl group, an alkoxy group or a halogen atom, M represents an n-valent metal atom, and n represents an integer of 1 to 3. R and X may be bonded to each other to form a ring.

Note that the alkyl group represents a saturated or unsaturated alkyl group or a cycloalkyl group, which has a substituent such as an aryl group, an alkoxy group, an aryloxy group, a carbon atom, an acylamino group, an aminocarbonyl group, or a cyan group. The aryl group represents a phenyl group, a naphthyl group or a heteroaromatic group, and these are
Alkyl group, alkoxy group, aryloxy group, No.10
Gen atom, nitro group, cyano group, substituted carbamoyl group,
It may have a substituent such as a substituted sulfamoyl group, a substituted amine group, a substituted oxycarbonyl group, a substituted oxysulfonyl group, a thioalkoxy group, an arylsulfonyl group or a phenyl group.

Among the substituents represented by R in the above formula, hydrogen atoms, phenyl groups, and alkyl groups with the number of carbon atoms /~ here are preferred,
Among the substituents represented by , magnesium, and calcium are preferred.

Among the substituents of the alkyl group and alkoxy group represented by , or an alkoxycarbonyl group are preferred.

From the viewpoint of water insolubility, the salicylic acid derivative according to the present invention preferably has a total number of carbon atoms of l≠ or more, particularly preferably /4 or more. These may be used in the form of metal salts,
It is also possible to use zinc oxide, for example, present in the dispersion to cause salt formation, adsorption or double decomposition in the dispersion.

Next, a specific example will be shown.

Hiro- is tadecyl salicylic acid, 3-phenyl salicylic acid, 3-cyclohexy salicylic acid, 3゜3-di-t-butyl salicylic acid, 3. ! - di-dodecylsalicylic acid, j
-MefA/--t-hensylsalicylic acid, 3-phenyl-2-(α,α-dimethylbenzyl)salicylic acid, 3.
! -di(α-methylbenzyl)salicylic acid, 3. ! −
D-t-octylsalicylic acid! -tetradecylsalicylic acid,! -hexadecylsalicylic acid,! -Octadecylsalicylic acid,! -α-(p-α-methylbenzylphenyl)ethylsalicylic acid, Hiro-dodecyloxysalicylic acid, Hiro-tetradecyloxysalicylic acid, Hiro-hexadecyloxysalicylic acid, Gu β-phenoxyethoxysalicylic acid, ≠-β-p-tolyloxy Ethoxysalicylic acid, ≠-β-p-ethylphenoxyethoxysalicylic acid, ≠-β-p-methoxyphenoxyethoxysalicylic acid, μmβ-p-ethoxyphenoxyethoxysalicylic acid, ≠-β-m-tolyloxyethoxysalicylic acid, Hiro-
β-0-)lyloxyethoxysalicylic acid, p-(r-
phenoxyoctyloxy) salicylic acid, etc.

In the above formula, R represents a hydrogen atom, an aryl group, an alkyl group, or a halogen atom, X represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and M represents a covalent metal;
n#i0,/or λ.

Specific examples include bis(2-hydroxy-j-butylphenyl)sulfone, bis(2-hydroxy-j-phenylphenyl)sulfone, bis(2-hydroxy-yo-octylphenyl)sulfone, bis(2-hydroxy-! −
chlorophenyl) sulfone, bis(2-hydroxy-3
-Chloro-! - zinc, such as phthylphenyl) sulfone,
Examples include nickel and magnesium salts.

(R)2Zn (A)2 (V) In the above formula, R is a monodentate or polydentate colorless organic ligand that binds to zinc and ions via a heteroatom to form a complex, and A is SCN. , α or a benzoic acid anion having an electron-withdrawing group.

Among the colorless organic ligands represented by R, pyridine, imidazole, quinoline, benzothiazole, benzimidazole, or amppyrine ligands are preferred, and these include alkyl groups, cyano groups, alkoxy groups, phenyl groups, amino groups, and formyl groups. , may be substituted with a vinyl group, etc. Specific examples include imidazole complexes of rhodan zinc, -
-7 dinylimidazole complex, picoline complex, pyridine complex, cobenzylimidazole complex, nizimidazole complex, co, J-dimethyl-/-722-3-pyrazoline-! -one m-form, /-phenyl-methyl-3
-Indyl-3-pyrazoline-! -onllHF,t-
Phenyl-comethyl-3-(2-ethylhexyl)-
J-ni'Lasolin! -one complex, l-phenyl-2-
Methyl-3-isopropyl-3-pyrazoline-! -one complex%/-phenyl2. ! - Jibe/Jirou Villa Sorin! -one complex, l-phenyl-2- is fujiru-3-methyl-pyrazoline-! -on complex 1 and the like.

These may be used alone or in combination. Among these, electron-accepting compounds consisting of salicylic acid derivatives and metal salts are preferred, and zinc salts are particularly preferred.

The recording material according to the present invention has one color-developing area that absorbs light in the near-infrared region and has sufficient color density, and the developed dye is extremely stable and hardly changes even with long-term light irradiation, heating, or humidification. Since it does not cause discoloration, it is particularly advantageous in terms of long-term preservation of records. In addition, when used as a heat-sensitive recording material, there is no disadvantage that the uncolored part develops color when exposed to solvents, or the colored body changes color or fades due to exposure to oils, fats, chemicals, etc., so it is close to ideal as a recording material. Has performance.

When used in thermal paper, the electron-donating colorless dye and electron-accepting compound have an ioμ or less size in the dispersion medium.

It is preferably used after being pulverized and dispersed to a particle size of 3 μm or less.

As a dispersion medium, Q,! A water-soluble polymer aqueous solution with a concentration of about 1 to 10% is used, and dispersion is carried out using a ball mill,
This is done using a sand mill, a structure sand mill, an attritor, a colloid mill, etc.

The ratio by weight of the electron-donating colorless dye to the electron-accepting metal compound used is preferably between /:IO and l2l, more preferably l:! Particularly preferred is a range of 3° to 7°. On the other hand, separately from the electron-donating colorless dye and the electron-accepting compound, calcium carbonate and/or zinc oxide are pulverized and dispersed in a dispersion medium.The amount of calcium carbonate and/or zinc oxide used is It is preferably 0.!-20 times (weight ratio), particularly preferably 7 to 70 times.Furthermore, a thermofusible substance can be contained in the thermosensitive coloring layer in order to improve its thermal responsiveness.

As an example of a preferable thermofusible substance, the following general formula (■) ~
Examples include compounds represented by ('A).

R5NlCONH2(X) R6CONH-R7(XI) In the formula, R1 to R4 are respectively a phenyl group, a benzyl group,
and represents a lower alkyl or non-rhodan substituted product thereof, R5 and R6 each represent an alkyl group, an aryloxymethyl group, or a benzyl group having a carbon number of 1 to λ, R
7 represents hydrogen or a phenyl group.

In addition, when the phenyl group or benzyl group represented by R1-R4 in general formulas (■) to ('A) is substituted with a lower alkyl group, the number of carbon atoms is 1 or more and r or less, preferably 1.
The above is 3 or less. When substituted with a halogen atom, fluorine is preferred. Also, formula (IX)
In, R4/ represents hydrogen or a hydroxyl group.

(XII) In the formula, A%B is an oxygen atom or a sulfur atom, R
8 represents a divalent group, preferably an alkylene group, an alkylene group having a carbonyl group, an alkylene group having a halogen atom, an alkylene group having an unsaturated bond, and more preferably an alkylene group or an alkylene group having an ether bond. . Further, x, y, z, xl, y/, and z/ may be the same or different, and are shown in a hydrogen atom, a halogen atom, an alkyloxycarbonyl group, and an aralkyloxycarbonyl group'.

The compounds of the general formulas (■) to (XI[) have a melting point of 70°
It is preferable that the melting point is from C to 130°C, and more preferably from rO°C to 130°C.

Specifically, benzyl p-benzyloxybenzoate (m
p, / /ri'c), β-naphthyl indyl ether (mp, 1Or0(H), stearic acid amide (m
p, / Or 'C), /" lucimi/acid amide (mp
, /OJ °C), N-7 engineering diary phosphoric acid amide (mp, P4 °C), N-stearylurea (mp
, /10'C), β-s7toic acid phenyl ester (mp-taco'C), /-hydroxy-λ-naphthoic acid phenyl ester (mp, taco00), β-s7tolic acid phenyl ester (p-chloro benzyl) ether (mp, //j'C
)% β-naphthol (p-methylbenzyl) ether (
mp-26°C), α-7tyl benzyl ether (r
ylp, 74'C), /, 44-butanediol-p-methylphenyl ether (mp, 23°C).

/, 4C-furopanediol-p'-)"!-ruphenyl ether (m,, Pj °C)% stearamide (mp, io4~ioP 'C), /, 4cm butanediol-p-inopropyl Phenyl ether (mp
,7ri'c),/,4A-buta/diol-pt-octylphenyl ether (mp-tata'C), cophenoxy/-p-)zyloxyethane (mp, toμ
'c), l-phenoxy-2-(4!-ethylphenoxy)ethane (mp.

iot °C), /-phenoxy-λ-(≠-chlorophenoxy)ethane (mp, 77 °C), /.

μm butanediol phenyl ether (mp -5'r
'c), diethylene glycol-bis(4I-methoxy-phenyl)ether (mp, 10/0C),'
p-ethylphenoxyacetic acid benzylamide (mp
.

5P4c'c), phenylacetic acid benzylamide (mp-
/ko≠'c), etc.

The thermofusible substance may be used alone or in combination, and in order to obtain sufficient thermal responsiveness, the trap is preferably used in an amount of 10 to 200% by weight based on the electron accepting compound. The preferred usage amount is 20-/0% by weight.

Additives are further added to the coating liquid obtained by mixing the dispersion thus obtained in an appropriate ratio 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 the releasability of the head. Fatty acids, metal soaps, etc. are added to increase the strength. Therefore, in addition to colorless dyes and electron-accepting compounds that contribute to color development, pigments, waxes, antistatic agents, ultraviolet absorbers, antifoaming agents, conductive agents, fluorescent dyes, surfactants, hindered phenol benzoin, etc. Additives such as acid derivatives are applied onto the support to constitute the recording material.

Specifically, pigments such as kaolin, calcined kaolin, Merck, diatomaceous earth, aluminum hydroxide, magnesium hydroxide, calcined gypsum, silica, magnesium carbonate, titanium oxide, alumina, parium carbonate, and sulfuric acid/lium , mica, -microballoon, urea-formalin filler, polyethylene noticle, cellulose filler, etc. particle size 0. / or l! Selected from μ. As for waxes.

Noma rough-in wax, carboxy-modified paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, and others.

Examples include higher fatty acid esters.

Examples of the metal stone include polyvalent metal salts of higher fatty acids, ie, zinc stearate, aluminum stearate, calcium stearate, zinc oleate, and the like.

As the hindered phenol, at least
Phenol derivatives in which one or more of the positions are substituted with a branched alkyl group are preferred.

For example, /, l-bis(2-methyl-≠-hydroxy-rt-7delphenyl)butane% l.

i,! -) Lis(3-methyl-Hiro-hydroxy-z-t
-methylphenyl)butane, bis(cohydroxy-J)
-t--fthyl-yo-methylphenyl)methane, bis(
Cometeru μm Hydroxy! -1-butylphenyl) sulfide, etc.

These are dispersed and applied in a binder.

As the benzoic acid derivative, a metal salt of benzoic acid having / or more electron-withdrawing groups is preferable, and specifically, halogen-substituted benzoic acid, nitrobenzoic acid, cyanobenzoic acid, substituted sulfonylbenzoic acid, acylbenzoic acid, substituted carbamoyl Examples include zinc salts, aluminum salts, cadmium salts, magnesium salts, calcium salts, etc. of benzoic acid, alkoxycarbonylbenzoic acid, substituted sulfamoylbenzoic acid, and the like.

Particularly preferred are zinc salts.

These can also be used as electron-accepting compounds.

These are mixed with an electron-accepting compound or dispersed alone 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, and imbutylene. Examples include maleic anhydride copolymer, polyacrylic acid, polyacrylic acid amide, methylol-modified polyacrylamide, starch derivatives, casein, and gelatin. In addition, water-resistant agents (gelling agents, cross-linking agents) are added to these binders for the purpose of imparting water resistance, hydrophobic polymer emulsions, A-type KH, styrene-butadiene rubber latex, acrylic resin emulsions, etc. You can also add

The coating liquid is base paper.

It is applied on high quality paper, synthetic paper, plastic sheet or neutral paper at a rate of about 2 to 10 y/rn2.

Furthermore, a protective layer of approximately O02 to -μ is provided on the coating surface layer, consisting of polyvinyl alcohol, a water-soluble or water-dispersible polymer compound such as droxyethyl starch or epoxy-modified polyacrylamide, and a crosslinking agent, to improve resistance. You can also do that.

When used for thermal paper, OLS Cococor! Various embodiments described in Japanese Patent Publication No. 12-20/II, etc. can be used. Alternatively, operations such as preheating, humidity control, or stretching of coated paper may be added prior to recording.

(Embodiments of the Invention) One embodiment will be shown below, but the present invention is not limited to this embodiment.

Example 1 Electron-donating dye according to the present invention [Compound Example (1)) 10F
, 1-coanilino 3-chloro-6-diethylaminofluorane Iry and 31.61-bisdiethylamino-yo-diethylaminospiro (isobenzofuran-7,
2'-Fluorene) + 3/-one IP, 'Wl solid compound ≠-β-p-methoxyphenoxyethoxyzinc salicylate 201, thermofusible substance cobenzyloxynaphthalene 1091 and stearic acid Each of Amide/jP was dispersed in a ball mill overnight with 1 ooy of Yochi polyvinyl alcohol (Cran PVA 10) aqueous solution to give a volume average particle size of 3 μm. On the other hand, a mixture of calcium carbonate and zinc oxide was added to 0.0% of sodium hexametaphosphate. It was dispersed with a homogenizer together with j% solution/JO1.

Disperse as above and prepare each dispersion as an electron-donating colorless dye dispersion jp, an electron-accepting compound dispersion LOY, and a thermofusible substance dispersion! Calcium carbonate and zinc oxide dispersion 22
A coating liquid was obtained by mixing a zinc stearate emulsion≠1 and an aqueous solution of flathead sodium (,2-ethylhexyl)sulfosuccinate. This coating liquid was dried on high-quality paper with a basis weight of toy/m2, and applied with a wire parser so that the coating amount was j P / door 2.
The coated paper was dried for 1 minute in an oven at a temperature of 100 m and then calendered to obtain a coated paper.

When color was developed using Fujitsu High Speed Facsimile pF-2000, a green-black image was obtained. This colored image had light absorption in the near-infrared region. Furthermore, when filter paper was impregnated with ethanol and castor oil and superimposed on the colored surface of the recording paper obtained by the above method, fogging in the white area and fading of one color (discoloration) in the colored area were almost never observed. There wasn't.

On the other hand, the obtained coated paper was heated to a high temperature (Go'C 130%RH).
J4C under high humidity (φo'c, 0%RH) conditions.
Although it was stored for several hours, there was almost no fogging.

Claims (1)

[Claims] A recording material characterized by containing an electron-donating colorless dye and an electron-accepting compound represented by the following general formula (I) ▲ Includes mathematical formulas, chemical formulas, tables, etc. ▼ (I) General formula (I) R_1, R_2, R_3, R_4 are hydrogen atoms, alkyl groups or aryl groups, R_5, R_
6, R_7 represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group, a substituted amino group or a halogen atom, and ring A represents an aromatic ring containing a hetero atom. R_1 and R_2, R_3 and R_4, and R_5 and R_
6 may be bonded to each other to form a ring.