JPH01161061A - Production of amorphous titanium phthalocyanine compound - Google Patents

Abstract

PURPOSE:To produce easily and stably the present compound excellent in exposure characteristics, spectral sensitivity, deterioration resistance and resistance to plate wear, by treating a titanium phthalocyanine compound with a metal oxide. CONSTITUTION:Phthalodinitrile is reacted with a titanium compound (e.g., TiCl4) at 150-300 deg.C in an organic solvent (e.g., alpha-chloronaphthalene), and the product is purified to obtain a titanium phthalocyanine compound. A mixture of this compound with a metal oxide (e.g., TiO2) of a particle diameter <=0.5mu at a weight ratio of 100/50-100/0.1 is optionally subjected to acid pasting or acid slurry treatment and is mechanically abraded to obtain an amorphous titanium phthalocyanine compound which shows no clear X-ray diffraction peak in an X-ray diffraction pattern.

Description

[Detailed explanation of invention] [Purpose of invention] (Industrial use field) The present invention is an excellent exposure sensitivity used as a charge generator regarding the manufacturing method of non -crystalline titarocyanine compounds. The present invention relates to an electrophotographic photoreceptor having characteristic 9 spectral sensitivity.

(Conventional technology) Conventionally, selenium has been used as the photoreceptor for electrophotographic photoreceptors.

Inorganic photoconductors such as selenium alloys, zinc oxide, cadmium sulfide and tellurium have been used primarily. In recent years, the development of semiconductor lasers has been remarkable, and small and stable laser oscillators have become available at low cost and are beginning to be used as light sources for electrophotography. but,
Using semiconductor lasers that emit short-wavelength light in these devices has many problems in terms of lifespan, output, etc. Therefore, the conventionally used materials sensitive in the short wavelength region are unsuitable for use in semiconductor lasers, and the materials sensitive in the long wavelength region (
It has become necessary to research materials with high sensitivity to wavelengths of 780 nm and above. Recently, research has been actively conducted on multilayer organic photoreceptors using organic materials, especially phthalocyanine, which is expected to have sensitivity in the long wavelength region. For example, as divalent phthalocyanines, ε-type copper phthalocyanine (ε-CuPc), X-type metal-free phthalocyanine (X-H2Pc), and τ-type metal-free phthalocyanine (τ-H2Pc) have sensitivity in the long wavelength region. Trivalent and tetravalent metal phthalocyanines include chloroaluminum phthalocyanine (AβPcCβ), chloroaluminum phthalocyanine chloride (CβAlPcC1),
Oxotitanium phthalocyanine (TfOPc) or chloroindium phthalocyanine (I n P c C
A method in which Ti is vapor-deposited and then brought into contact with the vapor of a soluble solvent to achieve long wavelengths and high sensitivity (JP-A-57-39484, JP-A-59-166959).

A method of long-wavelength treatment of phthalocyanine containing Sn and Pb using various substituents, derivatives, or shifting agents such as crown ether (Japanese Patent Application No. 59-36254)
(Japanese Patent Application No. 59-204045), sensitivity is obtained in the long wavelength region.

JP-A-59-166959 describes an electrophotographic photoreceptor provided with a charge photogenerating layer prepared by vapor-depositing oxotitanium phthalocyanine or indium chlorophthalocyanine on a substrate and then contacting it with vapor of a soluble solvent. Since this crystallizes the deposited layer, the film thickness becomes non-uniform, causing deterioration in electrophotographic characteristics and image defects.

Furthermore, a charge generation layer is prepared using oxotitanium phthalocyanine as described in JP-A No. 59-49544, and a charge generation layer is formed on the charge generation layer using a polyester whose main component is 2゜6-simethoxy9,10-dihydroxyanthracene. An electrophotographic photoreceptor provided with a charge transfer layer has a high residual potential.

There are many restrictions on how to use it.

The conventionally known oxotitanium phthalocyanine is.

This is due to the fact that it is a strongly aggregated lumpy particle, there are many impurities contained between the aggregated particles, crystal growth always occurs during crystallization, and the pigment particle size is large.

Charge generating layers deposited and dispersion coated using them lacked uniformity and dispersion stability. Thereby,
It was difficult to obtain a homogeneous charge generation layer, and it was not possible to obtain beautiful images or stable photoreceptors.

For example, JP-A-59-49544, JP-A-59-166
As is clear from the x-ray diffraction diagram shown in Publication No. 959, the oxotitanium phthalocyanine used does not have sufficient light absorption efficiency, resulting in a decrease in carrier generation efficiency in the charge generation layer and carrier transfer to the charge transfer layer. In addition, the electrophotographic materials did not fully satisfy various electrophotographic properties such as deterioration resistance, stiffness resistance, and image stability during repeated use over a long period of time.

Also, JP-A-61-109056, JP-A-61-17
No. 1771 and U.S.P. 4.664.997, an electrophotographic photoreceptor is provided with a charge generation layer containing a binder polymer and a titanium phthalocyanine compound purified by hot water treatment and N-methylpyrrolidone treatment.
Since the alcohols and ethers used before and after the thermal suspension treatment with methylpyrrolidone have strong polarity, the crystal particles of the titanium phthalocyanine compound strongly aggregate during the purification process, making subsequent purification difficult. Acids and intermediate impurities generated during synthesis tend to remain in or on the surface of the aggregated particles, and as a result, the N-methylpyrrolidone used in the next step decomposes and undergoes two reactions, resulting in a decline in electrical properties. .

In these cases, the light absorption efficiency is insufficient, resulting in a decrease in the carrier generation efficiency of the charge generation layer, a decrease in the carrier injection efficiency into the charge transfer layer, and a decrease in deterioration resistance and rigidity resistance during repeated use over a long period of time. The drawback was that various electrophotographic properties such as stability were not fully satisfied.

LEDs have also been put into practical use as digital light sources for printers. L'EDs in the visible light region are also used, but those that are generally put into practical use have an oscillation wavelength of 650 nm or more, typically 660 nm.

Azo compounds, perylene compounds, selenium, zinc oxide, etc.
It cannot be said that it has sufficient photosensitivity at around 650 nm.

The maximum sensitivity wavelength of electrophotographic photoreceptors using oxotitanium phthalocyanine as a charge generating agent that has been reported so far is only in the range of 780 to 830 (nm);
The sensitivity at 0 (nm) is low.

The photoreceptor for LED was insufficient.

(Problems to be Solved by the Invention) An object of the present invention is to provide an electrophotographic photosensitive material that has excellent exposure sensitivity characteristics (1) spectral sensitivity, as well as deterioration resistance, rigidity resistance, and image stability during repeated use over a long period of time. The object of the present invention is to stably and easily produce an amorphous titanium phthalocyanine compound that is a charge generating agent for the body.

[Structure of the invention]

(Means and actions for solving problems).

The present invention is a method for producing an amorphous titanium phthalocyanine compound that does not show a clear X-ray diffraction peak on an X-ray diffraction diagram. More specifically, in a method for producing a titanium phthalocyanine compound that does not show a clear X-ray diffraction peak on an X-ray diffraction diagram, metal oxides such as zinc oxide, titanium oxide, and silicon oxide are used for processing. This is a method for producing an amorphous titanium phthalocyanine compound.

The titanium phthalocyanine compound used in the present invention may have any substituent or number of substituents. Further, as long as the obtained titanium phthalocyanine compound is amorphous, it may be a single titanium phthalocyanine compound or a mixture of titanium phthalocyanine compounds having two or more types of chemical structural formulas.

Conventionally reported electrophotographic photoreceptors containing coarse crystalline particles in the charge generation layer suffer from a decrease in light absorption efficiency, resulting in a decrease in the number of carriers generated and a decrease in photosensitivity.

Furthermore, because the charge generation layer is non-uniform, the injection efficiency of carriers into the charge transport layer decreases, and as a result, the electrostatic properties include induction phenomena, a decrease in surface type, and potential stability during repeated use. Unfavorable phenomena occur in terms of the sensitivity of the photoreceptor, such as poor performance.

In addition, the two images lack homogeneity and produce minute defects.

The oxotitanium phthalocyanine used as the charge generation layer is 2θ (±2°) = 9.2° with radiation of Cukα of λ = 1.5418 (A, U, ).

13.1°, 20.7°, 26.2° and 27.1°
(where θ is the Bragg angle) has an X-ray diffraction peak (Japanese Unexamined Patent Publication No. 59-49544), 2θ = 7.5', 12.6
°.

Those with X-ray diffraction peaks at 13.0', 25.4°26.2' and 28.6@ (JP-A-59-166959)
), 2θ=7.5@, 12.3°, 16.3°, 25
．． α type (with X-ray diffraction peaks at 30 and 28.7°
JP-A No. 61-239248), 2θ=9.3', 10
゜6°, 13.2@, 15.1@, 15.7', 16.
1°.

β-type (Japanese Unexamined Patent Application Publication No. 1989-1999
-67094; US Pat. No. 4,664.997), but these are crystalline oxotitanium phthalocyanines, and the materials synthesized by each method and purified with solvents have many problems for the reasons described above. It is hard to say that it is a high-quality photoreceptor. There is also a patent (Japanese Unexamined Patent Publication No. 62-229253) that describes oxotitanium phthalocyanine obtained by acid pasting crude (crude material) as amorphous.

Acid-pasted crystals without metal oxides have Bragg angles of 7.5°, 16.3° and 25°3.
Since it has an X-ray diffraction peak at °, it is an α-type low-crystalline substance, and its spectral sensitivity at 600 nm is inferior to that at 700 to 8.00 nm. The photoreceptor using the quasi-amorphous type of the present invention as a charge generating agent has better sensitivity during light exposure than the oxotitanium phthalocyanine shown in 2 above, and the 1-minute spectral sensitivity is almost constant in the range of 600 to 850 (nm). shows good values.

The method for producing the amorphous titanium phthalocyanine compound of the present invention is shown below.

-C-wise, phthalocyanine is produced by the phthalodinitrile method, in which phthalodinitrile and metal chloride are heated and melted or heated in the presence of an organic solvent, and phthalic anhydride is heated and melted with urea and metal chloride, or heated in the presence of an organic solvent. Examples include, but are not limited to, the Weiler method, the method of reacting cyanobenzamide with a metal salt at high temperature, and the method of reacting dilithium phthalocyanine with a metal salt. Also as an organic solvent.

α-chloronaphthalene, β-chloronaphthalene, α-methylnaphthalene, methoxynaphthalene, diphenylethane, ethylene glycol, dialkyl ether 5-quinoline, sulfolane, dichlorobenzene.

Reaction-inert, high-boiling solvents such as dichlorotoluene are preferred. That is, the titanium phthalocyanine compound of the present invention is prepared by stirring, for example, phthalodinitrile and a titanium compound (preferably titanium tetrachloride, which has few by-products and is inexpensive) in the above organic solvent at a temperature range of 150 to 300°C. can be synthesized by Further, instead of phthalodinitrile, an indoline compound such as diiminoisoindoline or an indolenine compound such as 1-amino-3-iminoisoindolenine can be used.

The titanium compound is not limited to titanium tetrachloride, but may also be titanium trichloride, titanium tetrabromide, or the like.

The titanium-containing phthalocyanine used in the present invention is described in "Phthalocyanine Compounds J" by Moser and Thomas.
thalocyanine compounds”)
Compounds obtained by known methods such as acids, alkalis, acetone, methyl ethyl ketone, tetrahydrofuran, pyridine, etc. and appropriate methods mentioned above.

Quinoline, sulfolane, α-chloronaphthalene, toluene, dioxane, xylene, chloroform, carbon tetrachloride, dichloromethane, dichloroethane, trichloropropane, N,N'-dimethylacetamide.

Obtained by purification with N-methylpyrrolidone, N,N'-dimethylformamide, etc. Purification methods include washing methods, recrystallization methods, extraction methods such as Soxhlet, and thermal suspension methods. It is also possible to purify by sublimation.

The purification method is not limited to these, and any method may be used as long as it removes unreacted substances 9 reaction by-products and impurities.

Note that the titanium phthalocyanine compound according to the present invention is a phthalocyanine compound mainly having TiO as the core. However, TiCJ2. A material having a central core such as TiBr2 can be used as a starting material, but 2
It is difficult to stably obtain materials having TiC1, TiBr2, etc. as the central core because the central core can easily be changed to TiO through various treatments. Further, the titanium phthalocyanine compound may be a low halogenated titanium phthalocyanine compound.

The titanium titanium phthalocyanine compound obtained by the above method is crystalline and does not have sufficient sensitivity and properties. Therefore, the desired amorphous type can be obtained by further adding a crystal transition step. Amorphous titanium phthalocyanine compound.

Manufactured using the following steps. That is, to the crystalline titanium phthalocyanine compound produced in the above process.

After adding the metal oxide, treatment is performed by acid pasting or acid slurry method.

The acid/de pasting method and the acid slurry method are
This is a conventionally known pigmentation method using strong acids such as sulfuric acid. Acid pasting is a process in which crude pigment is dissolved in a relatively large amount of concentrated sulfuric acid, etc., and acid slurry is a process in which crude pigment is treated with sulfuric acid, etc. in an insufficient amount and concentration to dissolve the pigment. It is the law.

When performing the acid pasting method or the acid slurry method, low crystallinity is promoted by using a metal oxide during the above steps. That is, by adding a phthalocyanine molecule having a substituent to the orientation of phthalocyanine, the crystallinity is reduced.

It promotes low crystallinity. Therefore, in addition to the excellent exposure sensitivity characteristic 1 spectral sensitivity, it is possible to produce extremely uniform particles, and if necessary, the mechanical grinding step that is used is short and effective. It was.

The metal oxide is preferably zinc oxide, titanium oxide, silicon oxide, etc., but is not limited to these.

Furthermore, the titanium phthalocyanine compounds of the present invention are as follows.

It is often used in the charge generation layer of functionally separated photoreceptors because the charge generation layer has a thickness of 0.5 microns or less.

The metal oxide used preferably has particles of 0.5 microns or less.

The mixing ratio of the titanium phthalocyanine compound and the metal oxide varies depending on the crystal state of the titanium phthalocyanine compound, but is preferably 100150 (weight ratio).
~10010.1 (weight ratio) is good.

Furthermore, it is also possible to prepare a crystalline titanium phthalocyanine compound having a substituent during crude synthesis and obtain the titanium phthalocyanine compound of the present invention by reducing the mixing ratio of the phthalocyanine derivative or without mixing it.

The titanium phthalocyanine compound obtained by the above method does not have a clear X-ray diffraction pattern on its X-ray diffraction diagram. In the method described in JP-A No. 62-229253, in which a crude compound is simply acid-pasted, the This not only results in poor dispersibility when forming a coating liquid for the charge generation layer.

It was also inferior in terms of electrostatic properties.

Therefore, in order to improve the coating properties of the charge generation layer and to stably obtain high sensitivity, a step is required to make the two particles uniform. That is, it is important to adjust the particles of the titanium phthalocyanine compound immediately after chemical treatment by applying strain force or shear force by mechanical grinding.

In addition, after chemically treating the crystalline particles and then subjecting them to two mechanical treatments, the fine particles obtained are purified with the solvent used in the washing of the above-mentioned composite, and then chemically treated again. It goes without saying that it is desirable to improve the degree of purification and to form fine particles by repeating appropriate treatments many times. However, since phthalocyanine may be hydrolyzed by the acid basing method, depending on the material, a long-term grinding method using only mechanical methods may be selected.

The phthalocyanine compound according to the present invention is a non-crystalline particle having no clear interplanar spacing from which one diffraction angle cannot be read. Amorphous particles can also be obtained by sublimation. For example, it can be obtained by heating raw material phthalocyanine obtained by various methods under vacuum to 500° C. to 600° C. to sublimate it and promptly depositing it on a substrate. The phthalocyanine obtained by these methods is in an amorphous state.

Depending on the precipitation conditions, it becomes fine particles. More preferably, the particles are further finely divided by mechanical grinding. Equipment used for mechanical grinding includes a kneader, Banbury mixer, attritor, edge runner mill, roll mill, ball mill, and sand mill.

Examples include, but are not limited to, 5PEX mills, homo mixers, dispersers, agitators, show crushers, stamp mills, cutter mills, and micronizers.

Dispersion media that may be used include, but are not necessarily required to include, for example, glass beads, steel beads, zirconia beads, alumina balls, zirconia balls, steel balls, and flint stones.

Further, if necessary, it is also possible to use a grinding aid such as common salt or sulfur sulfate. For particle preparation, a dry method that applies strain force or shear force to the sample most efficiently, or a wet method that allows easy adjustment of particles uniformity is selected. The wet method uses a liquid solvent during grinding. for example.

Alcohol solvents such as glycerin, ethylene glycol, diethylene glycol, polyethylene glycol, carpitol solvents, cellosolve solvents, ketone solvents,
One or more types are selected from ester ketone solvents and the like.

In addition, metal oxides may be mixed before chemical treatment such as acid pasting or acid slurry, or
It may be mixed and mechanically ground after chemical treatment.

The charge generation layer using the titanium phthalocyanine compound obtained by the present invention is a uniform layer with high light absorption efficiency, and is formed between particles in the charge generation layer, between the charge generation layer and the charge transfer layer, and between the charge generation layer and the bottom layer. There is less air gap between the pull layer or conductive substrate, even during repeated use.

It is possible to obtain an electrophotographic photoreceptor that satisfies many requirements such as properties as an electrophotographic photoreceptor such as potential stability and prevention of increase in bright area potential, reduction in single image defects, and printing durability.

An n-type photoreceptor is fabricated by laminating an undercoat layer, a charge generation layer, and a charge transfer layer in this order on a conductive substrate. In addition, an n-type photoreceptor has two undercoat layers, a charge transfer layer, and a charge generation layer laminated in this order, or a charge generation agent and a charge transfer agent are dispersed and coated with a suitable resin on the undercoat layer. There is something created. If necessary, an overcoat layer may be provided on both photoreceptors for surface protection and prevention of toner filming.

Further, the 5th subbing layer can be removed if unnecessary.

It is also known that a charge generation layer can be obtained by vapor deposition.
The material obtained by the present invention has been processed down to minute primary particles and is amorphous, and impurities existing between the particles are removed, so it can be deposited very efficiently, and it can be used as a material for deposition. It is also effective as

(Example) Two embodiments of the present invention will be specifically described below.

In the examples, part means 1 part by weight.

Examples 1 to 3 After heating reaction of 20.4 parts of phthalodinitrile and 7.6 parts of titanium tetrachloride in 150 parts of quinoline at 220°C for 4 hours,
The solvent was removed by steam distillation. Next, 2% aqueous hydrochloric acid solution,
Subsequently, the sample was purified with a 2% sodium hydroxide aqueous solution and then with acetone, and the sample was dried to obtain 21.3 parts of oxotitanium phthalocyanine (T i OP c).

After adding and mixing metal oxides in the proportions shown in Table 1 to 10 parts of the obtained Ti0Pc, 200% of 97% sulfuric acid was added at 2°C.
The mixture is stirred for 1 hour while maintaining the temperature below 5°C. Next, this sulfuric acid solution was slowly poured into 2,000 parts of ice water with high speed stirring, and the precipitated crystals were passed through the mouth. The crystals were washed with distilled water until no acid remained, and then dried to form a titanium phthalocyanine compound. Each of the obtained titanium phthalocyanine compounds was ground in a ball mill for 10 hours.

Table 1 The X-ray diffraction pattern of the titanium phthalocyanine compound obtained in Example 1 is shown in FIG. It was an amorphous titanium phthalocyanine compound. The X-ray diffraction diagram of Example 2.3 was also almost the same as that of Example 1.

Next, a method for producing an electrophotographic photoreceptor will be described.

Copolymerized nylon (Amiran CM-8000 manufactured by Toshi) 10
was mixed with 190 parts of ethanol in a ball mill for 3 hours, and the dissolved coating liquid was spread with a wire bar on a sheet of polyethylene terephthalate (PET) film with aluminum vapor-deposited, and then dried at 100°C for 1 hour. A sheet having a subbing layer with a thickness of 0.5 microns was obtained.

2 parts of the titanium phthalocyanine compound obtained in this example were dispersed in a ball mill for 6 hours together with a resin solution prepared by dissolving 1 part of polyvinyl butyral resin (BH-3 manufactured by Block Chemical Co., Ltd.) in 97 parts of THF.

This dispersion was applied onto the undercoat layer and dried at 100°C for 30 minutes to form a charge generation layer of 0.2 microns.Next, 1-phenyl-1,2°3. 4-
Tetrahydroquinoline-6-carpoxyaldehyde 1
10 parts of ',1'-diphenylhydrazone.

Polycarbonate resin (Kijin Kasei Panlight 130
A solution prepared by dissolving 10 parts of 0) in 100 parts by weight of methylene chloride was applied onto the charge generation layer and dried to form a charge transfer layer of 15 microns, thereby obtaining an electrophotographic photoreceptor.

Its properties were measured.

Examples 4 to 6 Ti0Pc crudely synthesized in the same manner as in Examples 1 to 3 was acid pasted in the same manner as in Examples 1 to 3, except that no metal oxide was added. The obtained Ti0Pc
After adding and mixing 10 parts of each metal oxide in the proportions shown in Table 2, the mixture was ground in a two-ball mill for 20 hours.

Table 2 Examples 4 to 6 As a result of X-ray diffraction measurement, it was found that the titanium phthalocyanine compound was amorphous and did not show a clear X-ray diffraction peak. An electrophotographic photoreceptor was produced in the same manner as in Examples 1 to 3,
Its properties were measured.

Example 7 Zn was added to 10 parts of TtOPc crude prepared in Example 1.
After adding and mixing 5 parts of OO, the mixture was mixed with 80 parts of 78% sulfuric acid at 10°C and stirred for 1 hour while keeping the temperature below 10°C. This solution was poured into 400 parts of water, and the precipitated crystals were filtered. The crystals were washed with distilled water until no acid remained, and then dried to obtain a titanium phthalocyanine compound.

The Ti0Pc acid slurried by the above method was ground in a ball mill for 20 hours.

As a result of X-ray diffraction measurement, it was found to be an amorphous titanium phthalocyanine compound that did not show a clear X-ray diffraction peak. An electrophotographic photoreceptor was produced in the same manner as in Examples 1 to 3,
Its properties were measured.

Comparative Example 1 Ti0P produced by the method of Examples 1 to 3 and Pll except that no metal oxide was added during acid pasting.
c was ground in a ball mill for 50 hours.

Electrophotographic properties were measured by the following method.

Static mode 2. Corona charging is -5° 2KV with 1 surface potential (Vo) and 5Lux of white light or 1μ
Irradiate 800nm light adjusted to W to reduce the amount of charge to 1/2
The white light half-exposure sensitivity (El/2
) was investigated.

Table 3 shows the results.

Table 8 Photoreceptors using the titanium phthalocyanine compounds of Examples 1 to 7 as charge generating agents were superior in both chargeability (Vo) and sensitivity (E%) as compared to Comparative Example 1.2.

Therefore, it can be seen that the amorphous titanium phthalocyanine compound produced by adding a metal oxide becomes amorphous in a short time even after one mechanical grinding, and also has improved electrostatic properties.

〔Effect of the invention〕

By using the amorphous titanium phthalocyanine compound material obtained by this production method as a charge generating agent, a highly sensitive electrophotographic photoreceptor could be obtained. This photoconductor is most suitable as a photoconductor for printers that use semiconductor lasers and LEDs as light sources.

[Brief explanation of the drawing]

FIG. 1 was obtained in Example 1. 1 shows an X-ray diffraction diagram using CuKα rays of an amorphous titanium phthalocyanine compound.

Claims (1)

[Claims] 1. A method for producing a titanium phthalocyanine compound that does not show a clear X-ray diffraction peak on an X-ray diffraction diagram, characterized in that the titanium phthalocyanine compound is treated using a metal oxide. A method for producing an amorphous titanium phthalocyanine compound. 2. A non-crystalline method for producing a titanium phthalocyanine compound that does not show a clear X-ray diffraction peak on an X-ray diffraction diagram, which comprises subjecting the titanium phthalocyanine compound and metal oxide to acid pasting or acid slurry treatment. A method for producing a titanium phthalocyanine compound. 3. The method for producing an amorphous titanium phthalocyanine compound according to claim 2, wherein the metal oxide is one selected from zinc oxide, titanium oxide, and silicon oxide. 4. In a method for producing a titanium phthalocyanine compound that does not show a clear X-ray diffraction peak on an X-ray diffraction diagram, the titanium phthalocyanine compound and the metal oxide are subjected to acid pasting or acid slurry treatment and then mechanically milled. 1. A method for producing an amorphous titanium phthalocyanine compound.