JPH05247361A - Production of chlorogallium phthalocyanine crystal - Google Patents

Abstract

PURPOSE:To easily produce a chlorogallium phthalocyanine crystal having high sensitivity and durability and useful as a photoconductive material in a short time. CONSTITUTION:The objective chlorogallium phthalocyanine crystal having strong diffraction peaks at Bragg angles (2theta+ or -0.2 deg.) of 7.4 deg., 16.6 deg., 25.5 deg. and 28.3 deg. in X-ray diffraction spectrum can be produced by treating chlorogallium phthalocyanine with a solvent containing at least trifluoroacetic acid.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing chlorogallium phthalocyanine crystals.

[0002]

2. Description of the Related Art Hitherto, various materials have been proposed as a photosensitive material in an electrophotographic photosensitive member, and a laminated type electrophotographic photosensitive member in which a photosensitive layer is separated into a charge generating layer and a charge transporting layer. Also, various organic compounds have been proposed as charge generation materials. 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 near infrared semiconductor lasers (780 to 830 nm) and using it as a photoconductor for digital recording such as laser printers. From this viewpoint, the squarylium compound (Japanese Patent Laid-Open Nos. 49-105536 and 58-21).
416), triphenylamine-based trisazo compounds (JP-A-61-151659), phthalocyanine compounds (JP-A-48-34189 and 57-57).
No. 148745) has been proposed as a photoconductive material for semiconductor lasers.

When an organic photoconductive material is used as a photosensitive material for a semiconductor laser, first, the photosensitive wavelength region is extended to a long wavelength, and then the sensitivity and durability of the formed photoreceptor are good. Things are required. The above-mentioned organic photoconductive material does not fully satisfy these conditions. In order to overcome these drawbacks, the relationship between the crystal type and the electrophotographic characteristics of the above organic photoconductive material has been studied, and many reports have been made on phthalocyanine compounds.

Generally, phthalocyanine compounds show several crystal types depending on the production method and the treatment method, and it is known that the difference in the crystal types has a great influence on the photoelectric conversion characteristics of the phthalocyanine compound. .. Regarding the crystal form of the phthalocyanine compound, for example, when looking at copper phthalocyanine, α, ε,
Crystal forms such as π, x, ρ, γ, and δ are known, and these crystal forms can be mutually transferred by mechanical strain, sulfuric acid treatment, organic solvent treatment, heat treatment, etc. Are known (for example, US Pat. Nos. 2,770,629, 3,160,635 and 3,70).
8,292 and 3,357,989). Further, Japanese Patent Laid-Open Publication No. 50-38543 discloses a difference in crystal form of copper phthalocyanine and electrophotographic characteristics.
A comparison of α, β, γ and ε types indicates that ε type exhibits the highest sensitivity.

Regarding chlorogallium phthalocyanine, the crystal form of chlorogallium phthalocyanine having a specific Bragg angle is described in Journal of Electrophotography, 26, (3), 240 (1987). They differ from each other in crystal type, and there is no description of application to electrophotography. On the other hand, application to electrophotography is described in JP-A-59-44053, Shinkyo Giho CPM 81-69, 39 (1981) and the like, and JP-A 1-2
Japanese Patent No. 21459 describes chlorogallium phthalocyanine having a specific Bragg angle and an electrophotographic photosensitive member using the same. In addition, JP-A-2-26977
No. 6 discloses a method of treating phthalocyanine with trifluoroacetic acid, but does not mention chlorogallium phthalocyanine at all.

[0006]

However, not only the above-mentioned chlorogallium phthalocyanine but also the conventionally proposed phthalocyanine compounds are still sufficiently satisfactory in terms of photosensitivity and durability when used as a photosensitive material. It wasn't something. In order to improve this point, the present inventors have previously found that the Bragg angle (2θ ± 0.2 °) in the X-ray diffraction spectrum is 7.4 °, 16.6 °, 25.
A new chlorogallium phthalocyanine having strong diffraction peaks at 5 ° and 28.3 ° was proposed (Japanese Patent Application No. 3-
116630). However, since this chlorogallium phthalocyanine crystal is obtained by mechanically crushing the crystal after synthesis to make it substantially amorphous and then milling it in a solvent, it is a complicated manufacturing method and extremely time-consuming. Therefore, there is a problem that manufacturing efficiency is low. Further, as a chemical pigmentation method, the acid pasting method or the acid slurry method using sulfuric acid, which is generally used, cannot be used because chlorogallium granocyanine is hydrolyzed. ..

The present invention has been made in view of the above situation in the prior art. That is, the object of the present invention is, as a photoconductive material, a chlorogallium phthalocyanine crystal which is highly sensitive and gives high durability,
Another object of the present invention is to provide a manufacturing method with high manufacturing efficiency that can be manufactured in a short time.

[0008]

As a result of various studies, the present inventors have found that the above object can be achieved by treating chlorogallium phthalocyanine with a specific solvent, and have completed the present invention. That is, the production method of the present invention is characterized by treating chlorogallium phthalocyanine with a solvent containing at least trifluoroacetic acid, whereby the Bragg angle (2θ ± 2 It is possible to obtain chlorogallium phthalocyanine crystals having strong diffraction peaks at 0.2 °) at 7.4 °, 16.6 °, 25.5 ° and 28.3 °.

The present invention will be described in detail below. The chlorogallium phthalocyanine raw material used as a raw material in the present invention is a known method, for example, a method of reacting phthalonitrile and gallium chloride in a suitable organic solvent, diiminoisoindoline and trichlorogallium in a suitable organic solvent. It can be easily synthesized by a reaction method or the like.

The "solvent containing at least trifluoroacetic acid" in the present invention may be composed of trifluoroacetic acid alone or a mixture of one or more other organic solvents in combination. May be.
(Hereinafter, both of these are simply referred to as trifluoroacetic acid solvents.) Other organic solvents that can be used in combination with trifluoroacetic acid include aromatic hydrocarbons such as benzene and toluene,
Examples thereof include aromatic halogenated hydrocarbons such as monochlorobenzene and dichlorobenzene, halogenated hydrocarbons such as methylene chloride and chloroform, and fatty acids such as acetic acid and trichloroacetic acid. Among these, halogenated hydrocarbons are particularly preferable because they have high solubility in chlorogallium phthalocyanine and uniform crystals can be obtained.

When these organic solvents are used in combination,
The mixing ratio is not particularly limited, but it is preferably used in the range of 1 to 10 parts with respect to 2 parts of trifluoroacetic acid. In the present invention, the above trifluoroacetic acid is preferably used in an amount such that 2 parts or more of trifluoroacetic acid is contained in 1 part of chlorogallium phthalocyanine as a raw material, chlorogallium phthalocyanine. In this case, the raw material chlorogallium phthalocyanine is preferably completely dissolved in the trifluoroacetic acid solvent, but the desired crystalline chlorogallium phthalocyanine crystal can be obtained without being completely dissolved.

In the present invention, when the raw material chlorogallium phthalocyanine is treated with a trifluoroacetic acid solvent, when the chlorogallium phthalocyanine is not completely dissolved in the trifluoroacetic acid solvent, a chlorogallium phthalocyanine suspension solution is used. 30 ℃ ~
30 minutes to 4 hours in the temperature range of the boiling point of trifluoroacetic acid,
For example, it can be performed by stirring with a mechanical stirrer or the like. The treated chlorogallium phthalocyanine crystals are collected by filtration, but the chlorogallium phthalocyanine dissolved in the filtrate is recovered by precipitating with the poor solvent shown below to recover the chlorogallium phthalocyanine having the desired crystal form. You can

When chlorogallium phthalocyanine is completely dissolved in the trifluoroacetic acid solvent, the resulting solution is stirred at a temperature range of 0 ° C to 50 ° C for 10 minutes to 2 hours, for example, by a mechanical stirrer or the like. do it. The treated solution is then poured into a poor solvent organic solvent for chlorogallium phthalocyanine to precipitate crystals. Crystal precipitation is preferably performed at a temperature of 0 ° C to 50 ° C, preferably 0 ° C to room temperature. As a result, the target crystalline chlorogallium phthalocyanine can be obtained in good yield.

Examples of the poor solvent which can be used in the present invention include organic solvents such as alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, amides such as DMF, ethers such as THF and dioxane. Etc. You may use these things in mixture of 2 or more types. When water such as distilled water is used for crystal precipitation, the crystal type shown in FIG. 3 is formed. Therefore, it is preferable to use the above-mentioned organic solvent as the poor solvent.

When the amount of the poor solvent used in the precipitation of the chlorogallium phthalocyanine crystals is 1 part or more of the poor solvent with respect to 1 part of the solution, the desired yield of chlorogallium phthalocyanine can be increased. Therefore, it is preferable.

In the present invention, the chlorogallium phthalocyanine crystal-converted as described above may, if desired, be further treated with an organic solvent to the extent that crystal conversion does not occur for the purpose of adjusting the crystal form and particle size. Good. Examples of the organic solvent that can be used at that time include halogenated hydrocarbons such as methylene chloride and chloroform, aromatic hydrocarbons such as benzene, toluene and chlorobenzene, alcohols such as methanol and ethanol, and ketones such as acetone and methyl ethyl ketone. , Ethers such as THF and dioxane, acetic acid esters such as ethyl acetate and butyl acetate,
Aliphatic hydrocarbons such as hexane and octane can be used, and these can be used as a mixed solvent of two or more kinds or as a mixed solvent with water. At that time, the treatment may be carried out while milling using a ball mill, a sand mill or the like within a range where crystal conversion does not occur.

Next, an electrophotographic photosensitive member using the above chlorogallium phthalocyanine crystal as a photoconductive material in the photosensitive layer will be described. The electrophotographic photosensitive member of the present invention may have a photosensitive layer having a single-layer structure or a laminated structure in which a charge-generating layer and a charge-transporting layer are functionally separated. In the case where the photosensitive layer has a laminated structure, the charge generation layer is
It is composed of the chlorogallium phthalocyanine crystal and a binder resin.

The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferred binder resins include polyvinyl butyral, polyarylate (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin,
Insulating resins such as vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinyl pyridine, cellulosic resin, urethane resin, epoxy resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone may be mentioned. it can.

The charge generating layer is formed by dispersing the chlorogallium phthalocyanine crystal in a solution prepared by dissolving the binder resin in an organic solvent to prepare a coating solution and applying the coating solution on a conductive support. can do. In that case, the compounding ratio (weight) of the chlorogallium phthalocyanine crystal used and the binder resin is 40: 1 to 1:10, preferably 10: 1 to 1: 4. If the ratio of the chlorogallium phthalocyanine crystals is too high, the stability of the coating solution will be lowered, and if it is too low, the sensitivity will be lowered, so it is preferable to set the above range.

The solvent used is preferably selected from those which do not dissolve the undercoat layer or the charge transport layer.
Specific organic solvents include methanol, ethanol,
Alcohols such as isopropanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, amides such as N, N-dimethylformamide and N, N-dimethylacetamide, dimethyl sulfoxides, THF, dioxane, ethers such as ethylene glycol monomethyl ether , Esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, benzene, toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. Aromatic hydrocarbons and the like can be used.

The coating liquid can be applied by a coating method such as a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method or a curtain coating method. . In addition, drying is preferably performed by drying by touching at room temperature and then drying by heating. The heat drying can be performed at a temperature of 30 to 200 ° C. for 5 minutes to 2 hours in a static state or under blowing air. The thickness of the charge generation layer is usually 0.05
It is applied so as to have a thickness of about 5 μm.

The charge transport layer is composed of a charge transport material and a binder resin. Examples of the charge transport material include polycyclic aromatic compounds such as anthracene, pyrene, and phenanthrene, compounds having a nitrogen-containing heterocycle such as indole, carbazole, and imidazole, pyrazoline compounds, hydrazone compounds, triphenylmethane compounds, triphenylamine compounds. Any known compound such as an enamine compound and a stilbene compound can be used. Furthermore, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylanthracene, poly-N-vinylphenylanthracene, polyvinylpyrene, polyvinylacridine, polyvinylacenaphthylene, polyglycidylcarbazole, pyreneformaldehyde resin, ethyl. Examples include photoconductive polymers such as carbazole-formaldehyde resins, which may themselves form the layer. Further, as the binder resin, the same insulating resin as that used for the charge generation layer can be used.

The charge transport layer can be formed by preparing a coating solution using the above charge transport material, a binder resin and the same organic solvent as described above, and then applying the same. The compounding ratio (weight) of the charge transport material and the binder resin is usually 5: 1 to
It is set in the range of 1: 5. The thickness of the charge transport layer is usually set to about 5 to 50 μm.

When the electrophotographic photosensitive member has a single layer structure, the photosensitive layer is a photoconductive layer having a structure in which the chlorogallium phthalocyanine crystal is dispersed in a layer composed of a charge transport material and a binder resin. .. In that case, the compounding ratio (weight) of the charge transport material and the binder resin is 1:20 to.
It is preferable to set the compounding ratio (weight) of the chlorogallium phthalocyanine crystal to the charge transporting material at 5: 1 and the compounding ratio (weight) to about 1:10 to 10: 1. The charge transport material and the binder resin are
The same material as described above is used, and the photoconductive layer is formed in the same manner as described above.

As the conductive support, any support can be used as long as it is known to be used as an electrophotographic photoreceptor. In the present invention, an undercoat layer may be provided on the conductive support. The undercoat layer is effective in preventing unnecessary injection of electric charges from the conductive support, and has the function of increasing the chargeability of the photosensitive layer. Further, it also has the function of enhancing the adhesion between the photosensitive layer and the conductive support. As the material constituting the undercoat layer, polyvinyl alcohol, polyvinylpyrrolidone, polyvinylpyridine, cellulose ethers, cellulose esters, polyamide, polyurethane, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, Examples include polyacrylamide, zirconium chelate compounds, zirconium alkoxide compounds, organic zirconium compounds, titanyl chelate compounds, titanyl alkoxide compounds, organic titanyl compounds, silane coupling agents and the like. The thickness of the undercoat layer is 0.05 to
It is preferably set to about 2 μm.

[0026]

The present invention will be described below with reference to examples. In the examples, synthetic examples and test examples, "parts" means "parts by weight" unless otherwise specified.

Synthesis Example 1 30 parts of 1,3-diiminoisoindoline and 9.1 parts of gallium trichloride were placed in 230 parts of quinoline and reacted at 200 ° C. for 3 hours, then the product was filtered off and acetone was added. ,
After washing with methanol and then drying the wet cake,
28 parts of chlorogallium phthalocyanine crystal was obtained. The powder X-ray diffraction spectrum of the obtained chlorogallium phthalocyanine crystal is shown in FIG.

Example 1 1.0 g of the chlorogallium phthalocyanine crystal obtained in Synthesis Example 1 was mixed with 4 ml of trifluoroacetic acid and 1 ml of dichloromethane.
The mixture was added to 6 ml of the mixed solvent, stirred at room temperature for 1 hour, and then filtered using a glass fiber filter. The insoluble chlorogallium phthalocyanine remaining on the glass fiber filter was directly dried to obtain 0.5 g of chlorogallium phthalocyanine crystal. The powder X-ray diffraction spectrum of the obtained chlorogallium phthalocyanine crystal was
As shown in FIG. Further, the filtrate was added to 100 ml of methanol and stirred at room temperature for 1 hour, and then the precipitated crystals were separated by filtration,
It was thoroughly washed with methanol and dried to obtain 0.3 g of chlorogallium phthalocyanine crystal. The powder X-ray diffraction spectrum of the obtained chlorogallium phthalocyanine crystal was similar to that of FIG.

Examples 2 to 5 5.0 g of the chlorogallium phthalocyanine crystal obtained in Synthesis Example 1 was added to a mixed solvent of 50 ml of trifluoroacetic acid and 200 ml of dichloromethane, and the mixture was stirred at room temperature for 1 hour, and then a glass fiber filter was used. Filtered. A small amount of insoluble chlorogallium phthalocyanine crystals was confirmed. The filtrate was divided into 5 equal parts and each solvent shown in Table 1 was used.
It was poured into 0 ml to precipitate a chlorogallium phthalocyanine crystal, thoroughly washed with methanol, and then dried. The powder X-ray diffraction spectrum of the obtained chlorogallium phthalocyanine crystal is as shown in Table 1.

[0030]

[Table 1]

Comparative Example 1 3 parts of the chlorogallium phthalocyanine crystal obtained in Synthesis Example 1 was dissolved in 60 parts of concentrated sulfuric acid at 0 ° C., and the resulting solution was added dropwise to 450 parts of distilled water at 5 ° C. to crystallize. Was reprecipitated. Next, the obtained crystal was washed with distilled water and diluted ammonia and then dried to obtain 2.5 parts of hydroxygallium phthalocyanine crystal. The powder X-ray diffraction pattern of the obtained hydroxygallium phthalocyanine crystal is shown in FIG.

Comparative Example 2 1 part of the chlorogallium phthalocyanine crystal obtained in Synthesis Example 1 was dissolved in 40 parts of concentrated sulfuric acid at 0 ° C., and the resulting solution was added dropwise to 1 liter of methanol at 3 ° C. Did not precipitate.

Example 6 0.1 part of the chlorogallium phthalocyanine crystal obtained in Example 1 was combined with 0.1 part of polyvinyl butyral (trade name; S-Rex BM-S, Sekisui Chemical Co., Ltd.) and 1 part of cyclohexanone. After mixing and dispersing with glass beads by treating with a paint shaker for 1 hour, the obtained coating solution is applied by a dip coating method, and the mixture is heated at 100 ° C. for 5 hours.
It was heated and dried for a minute to form a charge generation layer having a film thickness of 0.2 μm. Next, 1 part of the following compound (I) and 1 part of poly (4,4-cyclohexylidenediphenylene carbonate) represented by the following structural formula (II) were dissolved in 8 parts of monochlorobenzene, and the obtained coating solution was prepared. , By an immersion coating method on an aluminum substrate on which a charge generation layer is formed,
It was heated and dried at 0 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm.

[Chemical 1]

[Chemical 2] MW = 39000 (viscosity average molecular weight)
The following measurements were performed using a flat plate scanner under the environment of (RH). The results are shown in Table 2.

Example 7 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the chlorogallium phthalocyanine crystal obtained in Example 2 was used, and the initial characteristics of the electrophotographic photosensitive member were measured.
The results are shown in Table 2.

Comparative Example 3 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the chlorogallium phthalocyanine crystal obtained in Comparative Example 2 was used, and the initial characteristics of the electrophotographic photosensitive member were measured. .. The results are shown in Table 2.

In Table 2, V _DDP , E _1/2 and V _RP
Has the following meaning: V _DDP : Surface potential one second after negatively charging by performing corona discharge of -6.0 KV. E _1/2 : Sensitivity with light dispersed at 800 nm using a bandpass filter. V _RP : Surface potential after irradiation with white light of 50 erg / cm ² for 0.5 seconds.

Example 8 0.5 part of the chlorogallium phthalocyanine crystal obtained in Example 2 was ball-milled with glass beads (1 mmφ, 30 g) and 15 parts of benzyl alcohol for 24 hours and then washed with methanol to obtain chlorogallium. 0.45 part of phthalocyanine crystal was obtained. The powder X-ray diffraction spectrum of the obtained chlorogallium phthalocyanine crystal was similar to that of FIG.

Example 9 An electrophotographic photosensitive member was prepared in the same manner as in Example 6 except that the chlorogallium phthalocyanine crystal obtained in Example 8 was used, and the initial characteristics of the electrophotographic photosensitive member were measured. .. The results are shown in Table 2.

[0039]

[Table 2]

[0040]

According to the method of the present invention, when a photoconductive material is used,
Since the chlorogallium phthalocyanine crystal having high sensitivity and high durability can be easily produced in a short time, the production efficiency is extremely good.

[Brief description of drawings]

FIG. 1 is an X-ray diffraction spectrum diagram of chlorogallium phthalocyanine of Synthesis Example 1.

FIG. 2 is an X-ray diffraction spectrum diagram of chlorogallium phthalocyanine crystals of Examples 1 to 5 and 8.

FIG. 3 is an X-ray diffraction spectrum diagram of a chlorogallium phthalocyanine crystal for reference.

4 is an X-ray diffraction spectrum diagram of a chlorogallium phthalocyanine crystal of Comparative Example 1. FIG.

Claims (3)

[Claims] 1. An X-ray diffraction spectrum characterized in that chlorogallium phthalocyanine is treated with a solvent containing at least trifluoroacetic acid, and has a Bragg angle (2θ ± 0.2 °) of 7.4 ° and 16 °. 6 °, 2
A method for producing a chlorogallium phthalocyanine crystal having strong diffraction peaks at 5.5 ° and 28.3 °. 2. The method for producing a chlorogallium phthalocyanine crystal according to claim 1, wherein the solvent is a mixed solvent of trifluoroacetic acid and a halogenated hydrocarbon solvent. 3. Dissolving in a solvent containing at least trifluoroacetic acid, and then injecting the obtained solution into an organic solvent which is a poor solvent for chlorogallium phthalocyanine to precipitate chlorogallium phthalocyanine. The method for producing a chlorogallium phthalocyanine crystal according to claim 1.