JPH0873768A - Production of gallium halide phthalocyanine crystal - Google Patents

Abstract

PURPOSE: To provide a process for producing a gallium halide phthalocyanine crystal which has a high sensitivity and an excellent durability and of which the conversion of crystal form can be easily done. CONSTITUTION: A gallium halide phthalocyanine crystal having diffraction peaks at least at Bragg angles (2θ±0.2 deg.) of 7.4 deg., 16.6 deg., 25.5 deg.. and 28.3 deg. in the X-ray diffraction spectrum is produced by mechanically grinding a gallium halide phthalocyanine, treating it with a carboxylic ester solvent, and subjecting it to crystal conversion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halogenated gallium phthalocyanine crystal and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, various inorganic and organic photoconductive substances have been known as photoconductive substances for electrophotographic photoreceptors. When used in electrophotography, the organic photoconductive substance has advantages such as transparency of the film, good film forming property, flexibility, and cost reduction. In order to improve the sensitivity and durability of the photoconductor when using an organic photoconductive material, a laminated electrophotographic photoconductor in which a charge generation layer and a charge transport layer are functionally separated has been proposed. In recent years, there has been an increasing demand for extending the photosensitive wavelength range of conventionally proposed organic photoconductive materials to the wavelength of a semiconductor laser of near infrared rays and using it as a photoconductor for digital recording such as a laser printer. From the square lilium compound (JP-A-49-105536 and JP-A-58-214).
16), triphenylamine-based trisazo compounds (JP-A-61-151659), phthalocyanine compounds (JP-A-48-34189 and JP-A-57-14).
No. 874) has been proposed as a photoconductive material for semiconductor lasers. When using an organic photoconductive material as a photosensitive material for a semiconductor laser, it is required that the photosensitive wavelength range is extended to a long wavelength, and then the sensitivity and durability of the formed photoreceptor are good. To be done.

In order to meet these demands, vigorous research and development of the above-mentioned organic photoconductive substances have been attempted. Especially, regarding the phthalocyanine compound, many reports have been made on its crystal form and electrophotographic characteristics. Has been done. In general, a phthalocyanine compound shows several crystal forms depending on a difference in a production method and a treatment method, and it is known that the difference in the crystal form has a great effect on the photoelectric conversion characteristics of the phthalocyanine compound. Regarding the crystal type of the phthalocyanine compound, for example, looking at copper phthalocyanine, in addition to the stable β type, α, ε, π, x,
Crystal forms such as ρ, γ, and δ are known, and it is known that these crystal forms can be mutually transformed by mechanical strain, sulfuric acid treatment, organic solvent treatment, heat treatment, or the like. (For example, U.S. Pat. Nos. 2,770,629, 3,
160,635, 3,708,292, and 3,357,989). Further, the metal-free phthalocyanine is known to have crystal forms such as α, β, γ and x. Furthermore, regarding chlorogallium phthalocyanine, the journal of the Electrophotographic Society, 26 (3), 240 (198).
7) describes the crystal form of chlorogallium phthalocyanine having a diffraction peak at a specific Bragg angle, but the crystal form is different from that of the present invention,
There is no mention of application to electrophotography. On the other hand, Japanese Patent Laid-Open No. 59-44053, Religion Technical Report CPM81-69,
39 (1981) and the like, there is a report on application to electrophotography, and JP-A-1-221459 discloses chlorogallium phthalocyanine having a diffraction peak at a specific Bragg angle and electrophotography using the same. A photoreceptor is described.

[0004]

However, the previously proposed phthalocyanine and the above-mentioned chlorogallium phthalocyanine cannot be said to have sufficient photosensitivity and durability, and in the production thereof, the conversion of the crystalline form is required. There are problems such as complicated operation and difficulty in controlling the crystal type. The present invention has been made to solve the above-mentioned problems of the prior art. That is, an object of the present invention is to provide a method for producing a halogenated gallium phthalocyanine crystal which has high sensitivity and excellent durability and can easily perform a crystal type conversion operation. Also,
Another object of the present invention is to provide a method for producing a halogenated gallium phthalocyanine crystal for obtaining an electrophotographic photoreceptor having excellent sensitivity characteristics, potential holding characteristics and image quality characteristics.

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that halogenated gallium phthalocyanine obtained by synthesis is mechanically crushed and then subjected to a solvent treatment for promoting crystal growth. , It was found that the characteristics as a photoconductive material are completely different depending on the type of solvent even though they are of the same crystal type, and the crude crystals are mechanically crushed and then treated with a specific organic solvent. It was confirmed that the halogenated gallium phthalocyanine crystal obtained by the above exhibits a very excellent performance as a photoconductive material for an electrophotographic photoreceptor, and the present invention has been completed.

That is, the halogenated gallium phthalocyanine of the present invention is mechanically pulverized and then treated with a carboxylic acid ester-based solvent for crystal conversion, so that the Bragg angle (2θ) in the X-ray diffraction spectrum is characterized.
± 0.2 °) of at least 7.4 °, 16.6 °, 2
It is a method for producing a halogenated gallium phthalocyanine crystal having diffraction peaks at 5.5 ° and 28.3 °.

Hereinafter, the present invention will be described in detail. The halogenated gallium phthalocyanine crystal of the present invention is Cu
Bragg angle for Kα characteristic X-ray (2θ ± 0.2 °)
Of at least 7.4 °, 16.6 °, 25.5 °, and 28.3 ° of
It can be obtained as follows.

First, the raw material gallium phthalocyanine halide is synthesized by a known method. For example, phthalonitrile or diiminoisoindoline and a metal chloride are dissolved by heating or in the presence of an organic solvent, the phthalonitrile method of heating, phthalic anhydride is dissolved by heating with urea and a metal chloride or in the presence of an organic solvent. It is synthesized by a Weiler method of heating, a method of reacting cyanobenzamide with a metal salt at a high temperature, a method of reacting dilithium phthalocyanine with a metal salt, or the like. The raw material halogenated gallium phthalocyanine has a Bragg angle (2θ ± 0.2 °) of at least 11.0 with respect to CuKa characteristic X-rays.
Those having strong diffraction peaks at °, 13.5 ° and 27.1 ° are preferably used.

As the organic solvent used in the above-mentioned synthetic method, α-chloronaphthalene, β-chloronaphthalene, methoxynaphthalene, diphenylethane, ethylene glycol, dialkyl ether, quinoline, sulfolane, dimethyl sulfoxide, dichlorobenzene, dichlorotoluene, etc. A solvent having a high boiling point, which is inert to the reaction of, is desirable.
As means for mechanically pulverizing the halogenated gallium phthalocyanine obtained by the above method, a vibration mill, an automatic mortar, a planetary ball mill, a sand mill, an attritor,
A crushing device such as a roller mill, a kneader, or a ball mill can be used, but is not limited to these.
In addition, if necessary, salt, sodium sulfate, methanol, ethanol, triethanolamine, ethylene glycol,
It is also possible to use a grinding aid such as stearic acid or lignin that can be easily removed after grinding. The amount of the grinding aid added is 0.1 g of gallium phthalocyanine halide.
-5% by weight is preferred. If too much grinding aid is used, it causes adhesion and reduces the grinding efficiency.
If it is less, the effect as a grinding aid is small.

Examples of the carboxylic acid ester solvent used in the present invention include methyl acetate, ethyl acetate, n-butyl acetate,
N-propyl acetate, n-pentyl acetate, isopentyl acetate, benzyl acetate, phenyl acetate, methyl formate, ethyl propionate, n-ethyl acetate, n-valerate, ethyl stearate, methyl benzoate, ethyl benzoate,
Organic solvents such as ethyl phenylacetate, isopropyl phenylacetate, methyl oxalate, ethyl malonate, ethyl adipate, ethyl maleate and ethyl phthalate can be mentioned, and these can be used alone or as a mixed solvent.

In the solvent treatment, the use ratio of the gallium phthalocyanine halide and the carboxylic acid ester is not particularly limited, but it is 1: 5 to 1:10 from the contact efficiency of both.
A range of 0 is preferred. The treatment temperature of the halogenated gallium phthalocyanine and the carboxylic acid ester is 0 ° C.
-200 degreeC, Preferably it is the range of 20-150 degreeC. If the treatment temperature is too high, a part of the phthalocyanine may be decomposed, and if it is too low, it takes a long time to proceed with crystal conversion, which is not practical. The treatment time depends on the treatment temperature and the amount of carboxylic acid ester used.
~ 50 hours are preferred.

The treatment method is not particularly limited, but a known method using a ball mill, an attritor, a sand mill, a dyno mill, a co-ball mill or the like together with a grinding medium such as glass beads, steel beads, alumina beads, zirconia beads, stone beads or the like is used. A method of pulverizing or mixing in a stirring tank is preferable. In the treatment method as described above, although the above-mentioned halogenated gallium phthalocyanine crystal has the same crystal type, depending on the kind of the solvent, the difference in the dissolving power for impurities or the difference in the dissolving power for the halogenated gallium phthalocyanine crystal results in It is presumed that the crystal surface defects due to the difference in the growth direction, the growth rate, etc. are slightly different.

Next, an electrophotographic photoreceptor containing a halogenated gallium phthalocyanine crystal obtained by the above treatment method in the photosensitive layer will be described. The electrophotographic photosensitive member obtained by using the present invention may have a single-layered photosensitive layer, or may have a laminated structure in which the charge-generating layer and the charge-transporting layer are functionally separated. In the electrophotographic photoreceptor,
As the conductive support, any support can be used as long as it is used in an electrophotographic photoreceptor. Further, if necessary, the surface of the conductive support can be subjected to various treatments within a range that does not affect the image quality. For example,
Surface anodizing treatment, surface roughening treatment such as liquid honing, chemical treatment, coloring treatment and the like can be performed.

In the case of a laminated type photoreceptor, a photosensitive layer in which at least a charge generation layer and a charge transport layer are laminated is provided on a conductive support, and the order of lamination is whichever is on the substrate side. May be. The charge generation layer in the present invention comprises a gallium phthalocyanine halide crystal and a suitable binder resin solution. At this time, the binder resin may be omitted. In the electrophotographic photoreceptor of the present invention, the gallium phthalocyanine halide crystal of the present invention may be used in combination with another known charge generating material as a charge generating material. on the other hand,
Any known binder resin can be used. For example, polycarbonate, polystyrene,
Polyester, methacrylic acid ester polymer, polyvinyl butyral, polyacetal, vinyl acetate polymer, vinyl chloride-vinyl acetate copolymer, cellulose ester,
Cellulose ether, polybutadiene, polyurethane,
Examples thereof include epoxy resin. The compounding ratio of the charge generating material and the binder resin is 40: 1 to 1: 4, preferably 20: 1 to
It is 1: 2. When the ratio of the charge generating material is too high, the stability of the coating solution is lowered, and when it is too low, the sensitivity is lowered, so that the above range is preferable.

As the solvent used for dispersion, methanol, ethanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone,
Methyl ethyl ketone, cyclohexanone, methyl acetate,
Examples thereof include organic solvents such as ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, benzene, toluene, xylene, chlorobenzene, dimethylformamide, dimethylacetamide, and mixed solvents thereof. As a dispersing means, a method such as a sand mill, a colloid mill, an attritor, a ball mill, a dyno mill, a co-ball mill or a roll mill can be used. As a coating method, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method,
A method such as a curtain coating method can be used. The film thickness of the charge generation layer is 0.01 to 5 μm, preferably about 0.03 to 2 μm.

The charge transport layer is composed of a charge transport material and a film-forming resin.
N'-diphenyl-N, N'-bis- (m-tolyl) benzidine, N, N'-bis- (p-tolyl) -N, N '
-Bis- (p-ethylphenyl) -3,3'-dimethylbenzidine, 4-diethylaminobenzaldehyde-
Any known compounds such as 2,2-diphenylhydrazone and p- (2,2-diphenylvinyl) -N, N-diphenylaniline can be used. Examples of the film-forming resin include polycarbonate, polyarylate, polystyrene, polyester, styrene-acrylonitrile copolymer, polysulfone, polymethacrylic acid ester, styrene-methacrylic acid ester copolymer, polyolefin and the like. Among these, polycarbonate is preferable in terms of durability. The compounding ratio (weight) of the charge transport material and the film-forming resin is 5: 1 to 1: 5, preferably 3: 1 to 1: 3. If the ratio of the charge transport material is too high, the mechanical strength of the charge transport layer will decrease, and if it is too low, the sensitivity will decrease, so the above range is preferred. Further, when the charge transport material has a film forming property, the film forming resin can be omitted. The charge-transporting layer is formed by dissolving the charge-transporting material and the film-forming resin in a suitable solvent and applying the solution.
It is preferably formed so as to have a thickness of ˜50 μm, preferably 10 to 40 μm. As a coating method for these photosensitive layers, any of the above-mentioned methods can be used.

When the photosensitive layer has a single layer structure, the photosensitive layer is composed of a photoconductive layer in which a gallium phthalocyanine halide crystal and a charge transport material are dispersed in a film forming resin. Here, as the charge-transporting material, any known material can be used, and as the film-forming resin, the same material as described above is used, and the photosensitive layer is formed by any of the methods described above. It At this time, the compounding ratio (weight) of the charge transport material and the film-forming resin is 1:20 to 5 :.
1. The compounding ratio (weight) of the halogenated gallium phthalocyanine crystal and the charge transport material is preferably set to about 1:10 to 10: 1.

Further, the electrophotographic photoreceptor may be provided with an undercoat layer between the photosensitive layer and the substrate, if necessary. The undercoat layer is effective for preventing unnecessary injection of electric charges from the substrate, and has the function of increasing the chargeability of the photoconductor.
Further, it also has the function of improving the adhesiveness between the photosensitive layer and the substrate. Further, the electrophotographic photoreceptor may be provided with a protective layer on the photosensitive layer in order to improve printing durability. The above electrophotographic photoconductor is effectively used in an electrophotographic copying machine, and further, a laser beam printer, an LED printer, a CRT printer, a microfilm reader,
It is applicable to plain paper FAX, electrophotographic plate making system, and the like.

[0019]

The present invention will be described in more detail with reference to the following examples. In the examples, "part" means "part by weight". Synthesis Example (Crystalline of chlorogallium phthalocyanine) 30 parts of 1,3-diiminoisoindoline and 9.1 parts of gallium trichloride were placed in 230 parts of quinoline, reacted at 200 ° C. for 4 hours, and then the product was separated by filtration. And washed with NN-dimethylformamide and methanol, and then the wet cake is dried, followed by chlorogallium phthalocyanine crystal 2
8 parts were obtained. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Example 1 Chlorogallim phthalocyanine crystal 20 obtained in the synthesis example
With 200 parts of 12 mmφ alumina beads,
It was placed in an alumina pot. This is a vibration mill (MB-1
Type, manufactured by Chuo Kakoki Co., Ltd.) and crushed for 100 hours.
The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG. Then, 10 parts of this crystal is 5 mm
After ball milling together with 150 parts of φ glass beads and 100 parts of ethyl benzoate at 25 ° C. for 6 hours, it was filtered and the wet cake was dried under reduced pressure to obtain 9 parts of chlorogallium phthalocyanine crystal. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG. The average particle size of the chlorogallium phthalocyanine crystal at this time was 0.08 μm as measured by a laser diffraction / scattering particle size distribution analyzer (LA700, manufactured by Horiba Ltd.).

Example 2 1.0 part of chlorogallium phthalocyanine crystals crushed by the same method as in Example 1 was stirred with 300 parts of n-butyl acetate in a reaction flask at 60 ° C. for 2 hours, and then the crystals were formed. It was washed with 50 parts of methanol and dried under reduced pressure to obtain a chlorogallium phthalocyanine crystal. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal showed the same spectrum as in FIG. 3, and the average particle size of the chlorogallium phthalocyanine crystal at this time was 0.15 μm.

Example 3 10 parts of chlorogallium phthalocyanine crystals crushed by the same method as in Example 1 was used to prepare 5 mmφ glass beads 150.
Part, 100 parts of ethyl phenylacetate, ball-milled at 25 ° C. for 6 hours, filtered and washed with 500 parts of methanol, and the wet cake was dried under reduced pressure to obtain 9 parts of chlorogallium phthalocyanine crystal. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal showed the same spectrum as in FIG. 3, and the average particle size of the chlorogallium phthalocyanine crystal at this time was 0.10 μm.

Comparative Example 1 10 parts of chlorogallium phthalocyanine crystal crushed by the same method as in Example 1 was used to obtain 5 mmφ glass beads 150.
Parts, chlorobenzene, and 100 parts of chlorobenzene for 6 hours at 25 ° C., followed by filtration and washing with 500 parts of methanol, and the wet cake was dried under reduced pressure to obtain 9 parts of chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal showed the same spectrum as in FIG. 3, and the average particle size of the chlorogallium phthalocyanine crystal at this time was 0.12 μm.

Comparative Example 2 1.0 part of chlorogallium phthalocyanine crystals pulverized in the same manner as in Example 1 was stirred together with 300 parts of dimethylformamide in a reaction flask at 60 ° C. for 2 hours, and then,
The crystals were washed with 50 parts of crystalline methanol and dried under reduced pressure to obtain chlorogallium phthalocyanine crystals. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal showed the same spectrum as in FIG. 3, and the average particle size of the chlorogallium phthalocyanine crystal at this time was 0.20 μm.

Comparative Example 3 10 parts of chlorogallium phthalocyanine crystal crushed by the same method as in Example 1 was used to prepare 5 mmφ glass beads 150.
20 parts at 25 ° C with 100 parts of ethylene glycol
After ball milling for an hour, it is filtered and methanol 500
Part, and the wet cake was dried under reduced pressure to obtain 9 parts of chlorogallium phthalocyanine crystal. The powder X-ray diffraction pattern of the obtained chlorogallium phthalocyanine crystal is shown in FIG.
At this time, the average particle size of the chlorogallium phthalocyanine crystal was 0.11 μm.

Application Examples 1 to 3 A polyvinyl butyral resin (S-REC BM-S, manufactured by Sekisui Chemical Co., Ltd.) (3 parts) was dissolved in 100 parts of a mixed solution of xylene / n-butyl acetate = 1/5 in advance. 3 parts of the chlorogallium phthalocyanine crystal obtained in each of Examples 1 to 3 was added, dispersed by a sand mill for 24 hours, diluted with the xylene / n-butyl acetate mixed solution, and a charge generation layer having a solid content concentration of 3.0% by weight. A forming coating solution was prepared.
The obtained coating liquid was coated on an aluminum substrate by a dip coating device and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.20 μm. A charge transport layer was formed on the formed charge generation layer. That is,
N, N'-bis- (p-tolyl) -N, N'-bis-
Polycarbonate Z resin 6 using 4 parts of (p-ethylphenyl) -3,3′-dimethylbenzidine as a charge transport material
40 parts of monochlorobenzene together with the solution, and the resulting solution is applied onto the charge generation layer by a dip coating device and dried by heating at 120 ° C. for 60 minutes to form a 20 μm-thick charge transport layer. A photoconductor was prepared. The electrophotographic characteristics of the electrophotographic photosensitive member produced as described above were measured as follows. 20 using an electrostatic copying paper tester (EPA-8100, manufactured by Kawaguchi Electric Co., Ltd.)
After charging the photoreceptor by corona discharge of -6 kV in an environment of 50 ° C and 50% RH, the light of the tungsten lamp is dispersed into monochromatic light of 800 nm using a monochromator,
The surface of the photoconductor was adjusted to 1 μW / cm ² and irradiated. The surface potential is 1 / V of the initial V0 (V).
The amount of exposure E1 / 2 (erg / cm ² ) until reaching ² was measured, and then the surface of the photoconductor was irradiated with light from a tungsten lamp of 10 lux for 1 second to measure the residual potential VR. further,
After repeating the above charging and exposure 1000 times, V0, E
1/2 and VR were measured. The results are shown in Table 1 below together with Reference Comparative Examples 1 to 3 below.

Reference Comparative Example 1 An electrophotographic photosensitive member produced by forming a charge generation layer and a charge transport layer in the same manner as in Application Example 1 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 1 was used. Was evaluated in the same manner as in Application Example 1. Reference Comparative Example 2 An electrophotographic photosensitive member produced by forming a charge generation layer and a charge transport layer by the same method as in Application Example 1 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 2 was used. Evaluation was performed in the same manner as in 1. Reference Comparative Example 3 An electrophotographic photosensitive member produced by forming a charge generation layer and a charge transport layer by the same method as in Application Example 1 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 3 was used. Evaluation was performed in the same manner as in 1.

[0028]

[Table 1]

[0029]

According to the present invention, as described above, the halogenated gallium phthalocyanine is mechanically crushed and then treated with a carboxylic acid ester, which is a simple production method.
It is possible to obtain a highly sensitive gallium phthalocyanine halide crystal having a photosensitive wavelength region extended to a long wavelength. Further, the electrophotographic photosensitive member produced by using the above-mentioned halogenated gallium phthalocyanine crystal has high sensitivity and good electrophotographic characteristics, and shows stable characteristics even after repeated use. It can be used as an electrophotographic photoreceptor having excellent properties.

[Brief description of drawings]

FIG. 1 shows a powder X-ray diffraction diagram of a chlorogallium phthalocyanine crystal obtained in a synthesis example.

FIG. 2 shows a powder X-ray diffraction diagram of a chlorogallium phthalocyanine crystal crushed in Example 1.

FIG. 3 shows a powder X-ray diffraction pattern of the chlorogallium phthalocyanine crystal obtained in Example 1.

FIG. 4 shows a powder X-ray diffraction diagram of a chlorogallium phthalocyanine crystal obtained in Comparative Example 3.

Claims (1)

[Claims] 1. A halogenated gallium phthalocyanine,
After being mechanically crushed, it is treated with a carboxylic acid ester solvent to perform crystal conversion, and at least a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum of at least 7.4 °, 16 ° .6 °, 25.5 ° and 2
A method for producing a gallium phthalocyanine halide crystal having a diffraction peak at 8.3 °.