JPH0797527A - Crystal of 3,3-bis(4-diethylamino-2-methylphenyl)-4,7-diazaphthalide and recording material containing the same crystal - Google Patents

Abstract

PURPOSE:To obtain a recording material by using a diazaphthalide compound having excellent characterlstics required as a colorant for recording material, such as whiteness of first coat, shelf stability of first coat and picture image fastness. CONSTITUTION:This recoding material contains 3,3-bis(4-diethylamino-2- methylphenyl)-4,7-diazaphthalide having crystal structure, especially the first crystal of 3,3-bis(4-diethylamino-2-methylphenyl)-4,7-diazaphthalide characterized by X-ray diffraction diagram showing a distinctive peak at a specific diffraction angle in powder X-ray diffraction method especially by Cu-Kalpha ray and the second crystal of 3,3-bis(4-diethylamino-2-methylphenyl)-4,7-diazaphthalide characterized by X-ray diffraction diagram showing a distinctive peak at another specific diffraction angle in powder X-ray diffraction method especially by Cu-Kalpha ray. Or a recording material contains these crystals as an electron donative colorant.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel crystal of a diazaphthalide compound and a recording material using the crystal.

More specifically, the present invention is excellent in novel crystals of a diazaphthalide compound useful as an electron-donating color former used in recording materials such as pressure-sensitive recording materials and heat-sensitive recording materials, and in various characteristics containing these crystals. Recording material.

[0003]

2. Description of the Related Art Conventionally, recording materials utilizing a color reaction between a colorless or light-colored electron-donating color developing agent (hereinafter referred to as a color developing agent) and an organic or inorganic electron-accepting color developing agent (hereinafter referred to as a color developing agent). Is already well known as a pressure-sensitive recording material, a heat-sensitive recording material, an electric heat-sensitive recording material and the like.

For example, a pressure-sensitive recording material is disclosed in Japanese Examined Patent Publication No. 42-2.
It is disclosed in Japanese Patent Publication No. 0144 and the like, and is used in fields such as slips and computer printers.

A heat-sensitive recording material is disclosed in Japanese Examined Patent Publication No. 45-14.
The measurement recorder, which is disclosed in Japanese Unexamined Patent Publication No. 039,
It is used in a wide range of fields such as facsimiles, printers, and ticket vending machines.

Such a recording material is required to be excellent in various properties such as background whiteness, background storage stability, color tone, color sensitivity, color density and storage stability of a color image. It is necessary to use a color former suitable for the purpose. Further, as a color former for pressure-sensitive recording materials, high solubility in capsule oil is also an important characteristic.

Further, in recent years, there is an increasing demand for recording materials capable of reading recorded images with an OCR (optical character reading device). As a recording material whose recorded image is compatible with OCR, a material using an azaphthalide compound or a diazaphthalide compound as a color former has been developed. These have excellent image light resistance, but have problems of poor background fog and poor storage stability. There is.

Many compounds are already known as diazaphthalide compounds, but they have the same chemical structure as the diazaphthalide compound of the present invention (compound represented by the structural formula (I) of the following [Chemical formula 1]). The one shown is disclosed in JP-A-48-65011, which is described as "having an unclear melting point". Further, the melting point of the material disclosed in Japanese Patent Publication No. 48-3204 is not described.

[0009]

[Chemical 1] JP-A-48-65011 and JP-B-48-320
3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide produced by the method described in Japanese Patent Publication No. 4 has no crystal structure and is amorphous (amorphous).
(Hereinafter, this known diazaphthalide compound is referred to as an amorphous substance), and a recording material using this amorphous substance has low background whiteness and background light fastness.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel crystal of a diazaphthalide compound excellent in the above-mentioned various properties as a color former for a recording material and a recording material using the same.

DISCLOSURE OF THE INVENTION As a result of intensive studies made by the present inventors to solve the above-mentioned drawbacks, 3,3-bis (4-
It has been found that diethylamino-2-methylphenyl) -4,7-diazaphthalide has a previously unknown stable crystal and that this crystal has excellent properties as a color former for pressure-sensitive and heat-sensitive recording materials. The present invention has been completed.

That is, according to the present invention, the diffraction angle (2θ ± 0.2 °) in the powder X-ray diffraction method using Cu-Kα rays is 10.
7 °, 12.2 °, 14.4 °, 22.0 °, 23.7
Crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide (hereinafter referred to as the diazaphthalide) characterized by a powder X-ray diffraction pattern having a characteristic peak at 2 °, 25.0 ° Compound crystal first
It is called a crystal. ), Diffraction angle (2θ ± 0.2 °) 10.6 °, 12.6 in powder X-ray diffraction method using Cu-Kα ray.
°, 14.4 °, 17.0 °, 19.4 °, 22.3
3,3-bis (4) characterized by a powder X-ray diffractogram with characteristic peaks at °, 23.3 ° and 25.5 °.
-Diethylamino-2-methylphenyl) -4,7-diazaphthalide crystal (hereinafter, the crystal of this diazaphthalide compound is referred to as the second crystal), and the first crystal and / or
Alternatively, it relates to a recording material containing the second crystal as a color former. 3,3-bis (4-diethylamino-2-) of the present invention
The first and second crystals of methylphenyl) -4,7-diazaphthalide are produced, for example, by the following method.
2,3-pyrazinedicarboxylic acid, 2,3-virazinedicarboxylic acid anhydride or a benzophenone compound represented by the structural formula (II) of the following [Chemical Formula 2]

[Chemical 2] And N, N-diethyl-m-toluidine are reacted in the presence of a dehydration condensing agent at 20 to 140 ° C. for several hours to several tens hours,
Next, the dehydration condensing agent is decomposed with water. The desired product is obtained by extracting the reaction product with an organic solvent, concentrating the organic solvent extract, and then adding alcohol as necessary to crystallize.

Acetic anhydride, acetic acid, polyphosphoric acid, phosphorus pentoxide, zinc chloride and the like can be used as the dehydration condensing agent, and acetic anhydride is particularly preferable. When acetic anhydride is used as the dehydration condensation agent, the reaction temperature is preferably in the range of 50 to 100 ° C.

Organic solvents include benzene, toluene,
Although xylene, chlorobenzene and the like can be used, usually toluene is preferably used.

As the alcohol, methanol, ethanol, n-propanol, isopropanol, n-butanol, n-pentanol and the like can be used, but usually methanol is preferably used.

In the method for producing 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide described in JP-A-48-65011, 2,3-pyrazinedicarboxylic acid and Reacting N, N-diethyl-m-toluidine in the presence of acetic anhydride for 10 minutes,
After neutralization with ammonia, the target substance is extracted with benzene and purified by column chromatography, and then petroleum ether is added to the benzene solution of the target substance for isolation. The primary precipitate of this isolate is described as "beautiful crystalline material" but is specified as "having an indistinct melting point".

Further, in Japanese Patent Publication No. 48-3204, N, N-diethyl-m-toluidine and anhydrous pyrazine-
It is reacted with 2,3-dicarboxylic acid for 5 hours in the presence of anhydrous zinc chloride, decomposed with water, extracted with benzene to make it alkaline, and then extracted with hydrochloric acid. The hydrochloric acid solution is neutralized with 10% caustic soda solution. You've got what you want. The melting point is not described.

The inventors of the present invention prepared (3,3-bis (4-diethylamino-2) by the production method described in these publications.
The production of -methylphenyl) -4,7-diazaphthalide was additionally tested, and it was confirmed that the obtained substance was an amorphous substance. The amorphous substance has a low and broad melting point, unlike the crystal of the present invention.

The first crystal and the second crystal of the present invention are capsule oils for pressure-sensitive recording materials, for example, commonly used SAS-2.
High solubility in 96 (Nippon Sekiyu KK), KMC-113 (Kureha Kagaku) and the like

Color forming recording materials such as pressure-sensitive recording materials and heat-sensitive recording materials using the first crystal and the second crystal of the present invention are
The whiteness of the background and the storage stability are high, and the image stability after color development is excellent. Particularly, the background characteristics of the heat-sensitive recording material are excellent as compared with those using known substances.

The first crystal and the second crystal of the present invention can be used alone in the recording material, or can be used in combination with other color forming agents, if necessary.

As the color-forming agent which can be used in combination, those which have been applied to this kind of recording material can be arbitrarily applied, and triphenylmethanephthalide type, fluorane type, fluorene type,
A coloring agent such as vinylogphthalide is preferably used.

Some examples of these are 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 2-anilino-3-methyl-6-dimethylaminofluorane and 2-anilino. -3-Methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6
-Dipropylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane, 2-anilino-
3-Methyl-6-dipentylaminofluorane, 2-anilino-3-methyl-6- (N-methyl-N-propylamino) fluorane, 2-anilino-3-methyl-6-
(N-ethyl-N-isobutylamino) fluorane, 2
-Anilino-3-methyl-6- (N-ethyl-N-isopentylamino) fluorane, 2-anilino-3-methyl-6- (N-methyl-N-cyclohexylamino) fluorane, 2-anilino-3 -Methyl-6- (N-ethyl-N-tetrahydrofurfurylamino) fluorane,
3,6-bis (dimethylamino) fluorene spiro [9,3 ′]-6′-dimethylaminophthalide, 3,3
-Bis {2,2-bis (p-dimethylaminophenyl)
Ethenyl} -4,5,6,7-tetrachlorophthalide,
3,3-bis {2,2-bis (1-ethyl-2-methylindol-3-yl) ethenyl} -4,5,6,7-
Tetrachlorophthalide and the like can be mentioned. These may be used alone or in combination of two or more.

In order to apply the first crystal and the second crystal of the present invention to the pressure sensitive recording material, various known methods disclosed in, for example, Japanese Patent Publication No. 42-20144 can be used. In general, after encapsulating a color former solution in which a color former is dissolved in an encapsulating solvent as a polymer compound,
The top paper is created by applying it to the back surface of a support such as high-quality paper, synthetic paper, or plastic film. On the other hand, a developer is applied to the surface of another support to prepare a lower sheet. When pressure is applied, such as writing pressure or tapping pressure, by overlapping the upper and lower sheets so that the coated surfaces are in contact with each other, the capsules in the pressed portion are destroyed, and the color former in the capsule becomes the developer. Reacting,
A recorded image is formed on the surface of the lower sheet. In addition, a plurality of copy records can be obtained by inserting several sheets of middle paper coated with a color developer on the surface of the support and a capsule on the back surface between the upper paper and the lower paper.

Also, a so-called self-contained paper type containing a color developer and a capsule on the same surface of the support, or one of the color developer and the capsule contained in the support and the other is coated. It can also be applied to the above-mentioned form.

The color developer used for the pressure-sensitive recording material is
Acid clay, salicylic acid derivative zinc salt, p-octylphenol resin zinc salt, p-phenylphenol resin and the like can be mentioned. Particularly, salicylic acid derivative zinc salt and p-octylphenol resin zinc salt are preferably used.

In order to apply the first crystal and the second crystal of the present invention to a heat-sensitive recording material, various known methods disclosed in, for example, Japanese Patent Publication No. 45-14039 can be used.
Generally, a color former, a color developer, and a sensitizer are dispersed together with a water-soluble polymer aqueous solution such as polyvinyl alcohol using an attritor, a sand mill or the like so that the particle diameter of the medicine is several microns or less. The sensitizer may be added to either or both of the color former and the developer, and may be dispersed at the same time. In some cases, a eutectic with the color former or the developer may be prepared and dispersed. May be. These dispersions are mixed, and if necessary, pigments, binders, waxes, metal soaps, antioxidants, ultraviolet absorbers, etc. are added to obtain a heat-sensitive coating liquid. A heat-sensitive recording material is obtained by applying the obtained heat-sensitive coating solution to a support such as high-quality paper, synthetic paper, plastic film and the like, and imparting smoothness thereto by calendering. The heat-sensitive coating liquid may be applied to a support having an undercoat layer of a heat insulating agent such as a plastic pigment or silica in order to improve the color developability, if necessary. further,
If necessary, in order to impart water resistance and chemical resistance, an overcoat layer may be provided on the thermosensitive recording layer with a water-soluble polymer aqueous solution or the like.

As the color developer used in the heat-sensitive recording material,
Various phenolic compounds can be used. Specific examples include 2,2-bis (p-hydroxyphenyl) propane (general name bisfer A), 2,2-bis (p-hydroxyphenyl) -4-methylpentane, 1,1-bis (p- Hydroxyphenyl) cyclohexane, bis (p
-Hydroxyphenyl) sulfone (generic name Bisfer S), bisphenol S monoisopropyl ether,
3,3′-diallyl bisphenol S, 1,5-bis (p-hydroxyphenylmercapto) -3-oxapentane, benzyl p-hydroxybenzoate, tetrabromobisphenol A, tetrabromobisphenol S and the like can be mentioned. Bisphenol A is particularly preferably used.

As the sensitizer, p-benzylbiphenyl, m-terphenyl, 2-benzyloxynaphthalene, 1,4-dibenzyloxynaphthalene, dibenzyl oxalate, di-p-methylbenzyl oxalate, 1,2. −
Diphenoxyethane, 1,2-di-m-toluoxyethane, 1,2-di-p-toluoxyethane, 1,4-diphenoxybutane, benzyl p-benzyloxybenzoate, phenyl 2-naphthoate, Examples thereof include phenyl 1-hydroxy-2-naphthoate and dibenzyl terephthalate. In particular, p-benzylbiphenyl, m-terphenyl, 2-benzyloxynaphthalene, oxalate di-p-
Methylbenzyl and 1,2-di-m-toluoxyethane are preferably used.

As the pigment, organic and inorganic pigments can be used. Preferred specific examples include calcium carbonate,
Examples thereof include barium sulfate, titanium oxide, aluminum hydroxide, amorphous silica, urea formalin resin powder, polyethylene resin powder and the like.

As the binder, water-soluble polymers and water-insoluble polymers can be used. Preferred specific examples include water-soluble polymers such as methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, styrene-maleic anhydride copolymer hydrolyzate, ethylene-maleic anhydride copolymer hydrolyzate, isobutylene-anhydrous. Maleic acid copolymer hydrolyzate, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide and the like, and examples of the water-insoluble polymer include styrene-butadiene rubber latex, acrylonitrile-butadiene rubber latex and vinyl acetate emulsion.

Preferred specific examples of the wax include paraffin wax, carboxy-modified paraffin wax,
Examples thereof include polyethylene wax.

As the metal soap, higher fatty acid metal salts are used. Preferred specific examples include zinc stearate, calcium stearate, aluminum stearate and the like.

Hindered phenols are used as the antioxidant. As the ultraviolet absorber, a benzophenone-based or benzotriazole-based ultraviolet absorber is used.

[0034]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. Example 1 Preparation of First Crystal of 3,3-Bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide 2- (4-Diethylamino-2-methylbenzoyl) pyrazine-3-carboxylic acid 6.26 g and N, N-diethyl-m-toluidine (3.26 g) were stirred in acetic anhydride (5.1 g) and toluene (10 ml) at 70 to 75 ° C for 3 hours.
After cooling the reaction mixture, 100 ml toluene and 100 water.
ml was added and stirred at 60-70 ° C for 30 minutes. The toluene layer is collected and 500m of 10% sodium chloride aqueous solution
It was washed twice with 1. After concentrating the toluene solution, 30 ml of methanol was added to the residue, and the mixture was refluxed for 1 hour and cooled. The crystals were collected by filtration and dried to give yellow crystals (7.4 g, yield 80.8).
%) Was obtained. The melting point, elemental analysis value and mass analysis value of this crystal were as follows. A powder X-ray diffraction pattern and an infrared absorption spectrum of this crystal are shown in FIG. 1 and FIG. 4, respectively. Melting point: 129.5 to 133.7 ° C. CHN elemental analysis value: theoretical value (C ₂₈ H ₃₄ N ₄ O ₂ ) 73.32% 7.49% 12.22% actual value 73.33% 7.51% 12.20% MS (m / e): 458 (M ⁺ )

Example 2 Production of Second Crystals of 3,3-Bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide 2,3-Pyrazinedicarboxylic acid 16.8 g, N, N- 32.6 g of diethyl-m-toluidine and 2 g of p-toluenesulfonic acid monohydrate in 75 g of acetic anhydride were used.
Stir at ~ 80 ° C for 24 hours. After cooling the reaction mixture,
Toluene 500 ml and water 500 ml are added, and 60-
The mixture was stirred at 70 ° C for 30 minutes. Then, the toluene layer was separated and washed twice with 1000 ml of 10% sodium chloride aqueous solution. After the toluene solution was concentrated, the residue was purified by column chromatography using silica gel and a developing solvent of toluene / ethyl acetate = 20/1. Concentrate the eluate of the target substance and add 60 ml of methanol to the residue.
After refluxing for a period of time, it was cooled. The crystals were collected by filtration and dried to obtain 21.9 g (yield 47.8%) of yellow crystals. The melting point, elemental analysis value, and mass analysis value of this crystal were as follows. The powder X-ray diffraction pattern and the infrared absorption spectrum of this crystal are shown in FIG. 2 and FIG. 5, respectively. Melting point: 136.2-139.8 ° C. CHN elemental analysis value: theoretical value (C ₂₈ H ₃₄ N ₄ O ₂ ) 73.32% 7.49% 12.22% measured value 73.35% 7.50% 12.19% MS (m / e): 458 (M ⁺ )

Reference Example 1 Production of Amorphous Substance of 3,3-Bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide 16.8 g of 2,3-pyrazinedicarboxylic acid was mixed with 1% of acetic anhydride.
It was dissolved in 00 ml, 40.75 g of N, N-diethyl-m-toluidine was added, and the mixture was refluxed for 10 minutes. The reaction mixture was discharged into 500 ml of ice water and neutralized with ammonia,
It was extracted with 500 ml of benzene. The benzene solution was washed with water, concentrated to a small amount, and purified by column chromatography using alumina and a developing solvent of toluene / ethyl acetate = 20/1. The eluate of the target substance was concentrated, the residue was dissolved in 10 ml of benzene, and then petroleum ether
0 ml was added and left overnight. The powder was collected by filtration and dried to obtain 8.2 g of yellow powder (yield 17.9%). The melting point, elemental analysis value and mass analysis value of this powder were as follows. The powder X-ray diffraction pattern and the infrared absorption spectrum of this powder are shown in FIG. 3 and FIG. 6, respectively. This powder did not show a specific peak as a crystal in the powder X-ray diffraction pattern. Melting point: 91.0 to 99.0 ° C. CHN elemental analysis value: theoretical value (C ₂₈ H ₃₄ N ₄ O ₂ ) 73.32% 7.49% 12.22% actual value 73.31% 7.46% 12.25% MS (m / e): 458 (M ⁺ )

[Reference Example 2] Production of amorphous substance of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide Anhydrous pyrazine-2,3-dicarboxylic acid 7.5 g, N, N
35 g of diethyl-m-toluidine and anhydrous zinc chloride 2
0 g was stirred at 90-95 ° C for 5 hours. The reaction mixture was decomposed with 100 ml of water under cooling, and unreacted N, N-diethyl-m-toluidine was removed by steam distillation. Then adjust the pH to 13 with caustic soda solution, and add benzene 2.
It was extracted twice with 00 ml. After concentrating the benzene extract, 5
Extracted with 1000 ml of hydrochloric acid. 1.0% hydrochloric acid extract
When neutralized with an aqueous solution of caustic soda, a viscous solid substance was precipitated. It was filtered and washed with water to obtain 5.1 g of a yellowish brown solid. As a result of a check by thin layer chromatography, this was a mixture containing a large amount of impurities showing blue and black-brown spots in addition to the target blue-green spots, and did not show a clear melting point. In powder X-ray diffraction analysis, no specific peak as a crystal was shown.

Example 3 Production of Pressure-Sensitive Recording Material 3 g of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide produced in Example 1 was added to KMC-113. (Kureha chemical solvent) 47g
Was dissolved under heating to prepare a color former solution.

On the other hand, 5 g of a system modifier (Emulsifier SM-100 manufactured by Mitsui Toatsu Chemicals, Inc.) was added to 100 g of water, and the pH was adjusted to 4 with an aqueous solution of caustic soda.
And 10 g of a melamine-form aldedo prepolymer (UMC-300 manufactured by Mitsui Toatsu Chemicals, Inc.) were added and emulsified with a homogenizer until the oil droplets became 4 microns. Then, the mixture was heated to 60 ° C. with stirring and stirred at the same temperature for 1 hour. After cooling to room temperature, the pH was adjusted to 7.5 with 25% aqueous ammonia to prepare a color developer capsule dispersion.

After thoroughly mixing 10 g of the color developer capsule dispersion thus prepared, 2 g of wheat starch and 1 g of latex, the mixture was coated on a fine paper to give a solid content of 5 g / m ^2, and dried. A white top paper was prepared.

Example 4 Production of Pressure Sensitive Recording Material Instead of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide, which is the color former in Example 3, , Manufactured in Example 2,
3-bis (diethylamino-2-methylphenyl)-
An upper paper was prepared in the same manner as in Example 4 except that the second crystal of 4,7-diazaphthalide was used.

Example 5 Production of Thermal Recording Material 2.5% of 5 g of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide produced in Example 1 was used. Polyvinyl alcohol aqueous solution 45
In g, a color mill dispersion was obtained by pulverizing with a sand mill so that the average particle diameter was 1 micron.

On the other hand, bisphenol A10 which is a color developing agent.
g and 10 g of p-benzylbiphenyl which is a sensitizer.
The mixture was pulverized in 80 g of a 5% polyvinyl alcohol aqueous solution using a sand mill so that the average particle size was 1 micron, to obtain a color developer dispersion.

After mixing the above two dispersions, 30 g of calcium carbonate 50% dispersion and 30% paraffin wax
15 g of the dispersion was added and mixed well to obtain a heat-sensitive coating liquid.

The heat-sensitive coating solution thus prepared was applied to a high-quality paper so that the solid content was 4.5 g / m ² .
After drying, the heat-sensitive recording material was prepared by calendering so that the Bekk smoothness of the heat-sensitive recording layer surface was 400 to 500 seconds.

Example 6 Production of Thermosensitive Recording Material Instead of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide which is the color former in Example 5, 3, produced in Example 2
3-bis (diethylamino-2-methylphenyl)-
A heat-sensitive recording material was prepared in the same manner as in Example 5, except that the second crystal of 4,7-diazaphthalide was used.

Comparative Example 1 Production of Pressure Sensitive Recording Material Instead of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide, which is the color former in Example 3, , Manufactured in Reference Example 1,
3-bis (diethylamino-2-methylphenyl)-
An upper paper was prepared in the same manner as in Example 3 except that the amorphous substance of 4,7-diazaphthalide was used.

Comparative Example 2 Production of Thermosensitive Recording Material Instead of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide which is the color former in Example 5, 3, manufactured in Reference Example 1
3-bis (4-diethylamino-2-methylphenyl)
A heat-sensitive recording material was prepared in the same manner as in Example 5, except that an amorphous substance of -4,7-diazaphthalide was used.

[Evaluation 1] Quality performance test of pressure-sensitive recording material Whiteness measurement and light resistance of CB surface of upper paper prepared in Examples 3 and 4 and Comparative Example 1 (surface of pressure-sensitive coating solution of upper paper) The test was done. The test and measurement were performed according to the following methods. Measurement of CB surface whiteness: The color density of the CB surface was measured by a reflection density value (OD value) with a reflection densitometer RD-914 (manufactured by Macbeth). Measurement of CB surface light resistance: After the CB surface was irradiated with a fluorescent lamp of 20,000 lux for 72 hours, the color density of the CB surface was measured in the same manner.

Next, the upper papers produced in the same manner as in Examples 3 and 4 and Comparative Example 1 were overlapped with the lower paper on which the zinc salt of salicylic acid derivative, which is a color developer, was applied so that the application surface of the paper was in contact with the miniroll. (Pressure 100 kgf / cm ² ) was used to develop color, and the color image density (OD value) was measured using a reflection densitometer RD-914.

Next, an image light fastness test was conducted according to the following method. Measurement of image light fastness: After the colored image was irradiated to a fluorescent lamp of 20,000 lux for 72 hours, the image density (OD value) was measured with a reflection densitometer RD-914.

The results are shown in Table 1.

[Table 1] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ CB side image performance ── ───────── ──────────── Color development image Lightfastness Whiteness Lightfastness Density (OD value) (OD value) (OD value) (OD value) ━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 3 0.07 0.14 0.77 0.71 Example 4 0.07 0.13 0.76 0.71 Comparative Example 1 0.09 0.17 0.75 0.70 ━━━━━━━━━━━━━━━━━━━━━━━━━ ━━━━━━━━━━━━━

CB side whiteness: The smaller the value, the higher the whiteness. CB surface light resistance: The smaller the value, the higher the light resistance of the CB surface. Colored image density: The higher the value, the higher the density. Image light resistance: The higher the value, the higher the light resistance of the image.

[Evaluation 2] Quality performance test of heat-sensitive recording materials The heat-sensitive recording materials prepared in Examples 5 and 6 and Comparative Example 2 were subjected to background whiteness test and background storage stability test according to the following methods. Measurement of background whiteness: The background color density of the thermal recording material was measured with a reflection densitometer RD-914 (manufactured by Macbeth) to obtain a reflection density value (OD).
Value). Moisture and heat resistance measurement of background: heat sensitive recording material at 50 ° C, 90% R
After being exposed to H condition for 24 hours, the background coloring density (OD
Value) was measured with a reflection densitometer RD-914. Measurement of background heat resistance: Thermal recording material at 60 ° C, 20% RH
After 24 hours of exposure to the above conditions, the background color density (OD value)
Was similarly measured. Measurement of background light resistance: After the thermosensitive recording material was irradiated with a fluorescent lamp of 20,000 lux for 72 hours, the coloring density (OD value) of the background was measured in the same manner.

The results are shown in Table 2.

[Table 2] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Background whiteness and background preservability ─ ──── ─────────────────────── Moisture and heat resistance Heat resistance Light resistance (OD value) (OD value) (OD value) (OD value) ━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 5 0.12 0.22 0.21 0.18 Example 6 0.11 0.20 0.18 0.16 Comparative Example 2 0.21 0.37 0.32 0.28 ━━━━━━━━━━━━━━━━━━━━━ ━━━━━━━━━━━━━━━━ Background whiteness: The smaller the value, the higher the whiteness. Storage stability of background: The smaller the value after each test, the higher the storage stability of the background.

Next, the thermosensitive recording materials similarly prepared in Examples 5 and 6 and Comparative Example 2 were subjected to color development with a pulse width of 0.90 ms by using a printer TH-PMD to obtain a color image density (OD).
The value) was measured using Macbeth RD-914. Then, an image storage stability test was performed on the obtained image according to the following method. Measurement of image moist heat resistance: After the color image was exposed to the conditions of 50 ° C. and 90% RH for 24 hours, the image density (OD value) was measured with a reflection densitometer RD-914. Measurement of image heat resistance: After exposing the color image to the conditions of 60 ° C. and 20% RH for 24 hours, the density (OD value) of the image was similarly measured. Measurement of image light fastness: The color image was irradiated with a fluorescent lamp of 20,000 lux for 72 hours, and then the image density (OD value) was similarly measured.

Each image fastness is represented by the following formula.

Fastness (%) = (image density after test / color image density) × 100 These results are shown in Table 3.

[Table 3] ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Colored image density Image fastness ─ ──────────────────── (OD value) Moisture and heat resistance Heat resistance Light resistance (%) (%) (%) ━━━━━━━━━━━ ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Example 5 1.05 93 98 83 83 Example 6 1.04 95 100 100 84 Comparative Example 2 1.06 93 97 82 ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Colored image density: The higher the value, the higher the image density. Show high. Image fastness: The higher the value, the higher the image fastness.

As is clear from Tables 1, 2 and 3, the first and second crystals of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide of the present invention were detected. When used as a color-developing agent for pressure-sensitive recording materials and heat-sensitive recording materials, the whiteness and storage stability of the CB surface and the background are high and the image fastness is excellent as compared with the amorphous substance having the same structure.

[0063]

The recording material using the first and second crystals of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide according to the present invention has the whiteness of the background and the preservation. Since it is particularly excellent in various properties such as stability and image fastness, it is very useful as a color former for recording materials such as pressure-sensitive recording materials and heat-sensitive recording materials.

[Brief description of drawings]

FIG. 1 is a powder X-ray diffraction pattern of a first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide produced in Example 1.

FIG. 2 is a powder X-ray diffraction diagram of a second crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide prepared in Example 2.

FIG. 3 is a powder X-ray diffraction diagram of an amorphous substance of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide prepared in Reference Example 1.

FIG. 4 is an infrared absorption spectrum of the first crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide produced in Example 1.

FIG. 5 is an infrared absorption spectrum of a second crystal of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide prepared in Example 2.

FIG. 6 is an infrared absorption spectrum of an amorphous substance of 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide prepared in Reference Example 1.

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[Submission date] November 16, 1993

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 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Sayuri Wada, 1-43 Minami, Yugemachi, Yao-shi, Osaka Prefecture Yamamoto Kasei Co., Ltd. Within

Claims (6)

[Claims] 1. 3,3-Bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide having a crystal structure. 2. A diffraction angle (2θ ± 0.2 °) of 10.7 °, 12.2 in a powder X-ray diffraction method using Cu-Kα rays.
°, 14.4 °, 22.0 °, 23.7 °, 25.0 °
The 3,3-bis (4-diethylamino-2-methylphenyl) -4,7-diazaphthalide according to claim 1, characterized by a powder X-ray diffractogram having a peak characteristic of 3. A diffraction angle (2θ ± 0.2 °) of 10.6 ° and 12.6 in a powder X-ray diffraction method using Cu-Kα rays.
°, 14.4 °, 17.0 °, 19.4 °, 22.3
3,3-Bis (4-diethylamino-2-methylphenyl) -4, according to claim 1, characterized by a powder X-ray diffractogram with characteristic peaks at °, 23.3 ° and 25.5 °. 7-diazaphthalide. 4. A recording material utilizing a color-forming reaction between an electron-donating color former and an electron-accepting color developer, the recording material containing the crystal according to claim 1 as the electron-donating color former. 5. The recording material is a pressure-sensitive recording material.
Recording material described. 6. The recording material is a heat-sensitive recording material.
Recording material described.