JPH0578828B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an optical semiconductor material with excellent storage stability using a phthalocyanine composition containing a phthalocyanine derivative. Furthermore, electrophotographic characteristics,
For example, the present invention relates to an optical semiconductor material that can provide an electrophotographic photoreceptor, etc., which has excellent photosensitivity and image quality stability after repeated use, and is also excellent in hygiene. Applications of optical semiconductor materials include electrophotographic photoreceptors, solar cells, electrophotographic plate-making materials, sensors, and the like. Generally, in the electrophotographic method, a photoconductor made of a thin film of photoconductor such as selenium or cadmium sulfide formed on a metal drum is charged in a dark place, and a light image is irradiated (exposed), as in the xerographic method. After forming an electrostatic latent image, a visible image is created with toner (development), and this is transferred and fixed onto paper, etc., or a photoconductive layer (photosensitive layer) is placed on paper as in the electrofax method. A charge is applied to the photoconductor.
There is a method of obtaining a permanent visible image on the photoconductive layer by exposure, development and fixing. Inorganic compounds that are currently widely used as optical semiconductor materials for electrophotographic photoreceptors include amorphous selenium, cadmium sulfide, and zinc oxide. On the other hand, known organic compounds include polyvinylcarbazole (PVK), phthalocyanine, and azo. Although these optical semiconductors have excellent flexibility and processability, they do not have sufficient electrophotographic sensitivity for practical use when used alone, and they can be increased by using chemical sensitization and optical sensitization in combination. It is felt. As a chemical sensitizer, 2,4,7-trinitro-9
-Polycyclic or heterocyclic nitro compounds such as fluorenone (TNF), 2,4,5,7-tetranitro-9-fluorenone (TENF), quinones such as anthraquinone, and nitrile compounds such as tetracyanoethylene are known. ing. Furthermore, xanthene dyes and quinoline pigments are known as optical sensitizers. Phthalocyanine photosemiconductors provide excellent electrophotographic photoreceptors among organic photosemiconductors, but alpha-type phthalocyanine, which is usually called an unstable type, and ε-type phthalocyanine, which is a semi-unstable type, cannot be used for long periods with organic compounds such as organic solvents and plasticizers. When in contact for a period of time, these phthalocyanines gradually become coarse particles and finally transform into stable β-type phthalocyanine. This is also observed in the production of electrophotographic photoreceptors using phthalocyanine. In other words, when phthalocyanine is dispersed in a vehicle or solvent such as a paint, the size and shape of phthalocyanine particles change, or a phenomenon accompanied by a change in the crystalline state is observed. The physical properties may change significantly and the product value may be lost. This tendency is particularly strong in unstable or semi-unstable (crystalline) phthalocyanines having one type of crystal form selected from α-type and ε-type, and improvement thereof is desired. For example, when an electrophotographic photoreceptor is prepared by coating a conductive support with a coating material in which phthalocyanine photosemiconductors are dispersed in a resin and an organic solvent, the phthalocyanine aggregates or aggregates during storage of the coating material, and This causes crystal transition or coarsening of phthalocyanine particles, resulting in deterioration of electrophotographic properties. Alternatively, when the resin is thermally cured after being applied to a conductive support using a coating agent, coarsening of crystal particles and crystal transition are caused. In addition, when a charge transfer agent with a relatively low molecular weight and melting point is used in combination, the phthalocyanine gradually becomes coarser or undergoes crystal transition when used at high temperatures, resulting in significant deterioration of electrophotographic properties. In practice, this is a disadvantage of using unstable or semi-unstable (crystalline) phthalocyanine having one type of crystal form selected from α-type and ε-type. The present inventors conducted various studies to solve the above-mentioned drawbacks, and found that phthalocyanine, which stabilizes phthalocyanine crystals against organic solvents such as aromatic compounds, plasticizers, and other low-molecular organic compounds, has been developed. By combining a derivative with an unstable or quasi-unstable phthalocyanine photosemiconductor, we discovered a photosemiconductor material that not only has excellent photosensitivity and stability over time, but also has excellent disaggregation or crystal stability, and completed the present invention. This is what I did. In the present invention, the mixing method is not particularly limited, and various methods may be used. Furthermore, the present invention solves the above-mentioned drawbacks, and has a photosensitivity comparable to that of a cadmium sulfide photoreceptor, without requiring chemical sensitizers that pose problems in terms of hygiene, etc. The present invention relates to an optical semiconductor material containing a phthalocyanine composition that has excellent stability, is industrially useful, and has excellent hygiene properties. That is, it is an optical semiconductor material consisting of an unstable or semi-unstable phthalocyanine optical semiconductor and a phthalocyanine derivative that stabilizes the crystals of the phthalocyanine. Additionally, some methods are being considered using phthalocyanine derivatives for phthalocyanine.
However, in these methods, a phthalocyanine derivative is added to obtain a phthalocyanine having properties as an optical semiconductor, for example, to obtain an ε-type phthalocyanine. The optical semiconductor material according to the present invention is, for example, as follows:
It can be manufactured or used by the methods described in (1) to (5). (A) A method of mixing unstable or semi-unstable phthalocyanine photosemiconductors and phthalocyanine derivatives synthesized or prepared in advance by the methods described in (1) to (3) below; (B) Unstable or semi-unstable phthalocyanine photosemiconductors and phthalocyanine derivatives synthesized or prepared in advance are mixed in the manner described in (1) to (3) below. The method includes a method of mixing a phthalocyanine photosemiconductor and a phthalocyanine derivative using the methods described in (4) and (5) below, but the present invention is not limited thereto. Examples of mixing methods include (1) uniformly mixing an unstable or quasi-unstable phthalocyanine photosemiconductor and a phthalocyanine derivative by mechanical milling using a known method; Regular or semi-unstable phthalocyanine photosemiconductors and phthalocyanine derivatives are mixed using a conventional mixing device.
For example, mixing in a tumbler for mixing powders, (3) mixing unstable or semi-unstable phthalocyanine optical semiconductors and phthalocyanine derivatives with a suitable organic solvent such as xylene in a mixer, (4) binder resin. , or adding an unstable or semi-unstable phthalocyanine photosemiconductor and a phthalocyanine derivative to a binder resin and a solvent, and dispersing it with a device such as a ball mill or sand mill, (5)
The phthalocyanine derivative or the unstable or semi-unstable phthalocyanine photosemiconductor is simply added to the unstable or semi-unstable phthalocyanine photosemiconductor or the phthalocyanine derivative dispersed in a binder resin. Examples of the phthalocyanine of the unstable or semi-unstable phthalocyanine photosemiconductor according to the present invention include metal-free phthalocyanine or metal phthalocyanine;
Or a mixture of these. Metal phthalocyanines include copper, silver, beryllium, magnesium, calcium, zinc, cadmium, barium, mercury, aluminum, gallium, indium, lanthanum, neodymium, samarium, europium, gadolinium, dysprosium, holmium, sodium, lithium, and ytterbium. , lutetium, titanium, tin, hafnium, lead, thorium, vanadium, antimony, chromium, molybdenum, uranium, manganese, iron, cobalt, nickel, rhodium, palladium, osmium, and platinum. Furthermore, the central core of the phthalocyanine may not be a metal atom, but a metal halide having a valence of 3 or more. Metal-free phthalocyanines and metal phthalocyanines such as copper, cobalt, lead, and zinc are preferred. Furthermore, it may be a low halogenated phthalocyanine. Although phthalocyanine is a well-known compound as a pigment, in the present invention, phthalocyanine obtained by any manufacturing method may be used. Further, phthalocyanine having various crystal forms is known, but in the present invention, a phthalocyanine optical semiconductor having an unstable or semi-unstable crystal form is used. For example, α type, γ type, δ type, ε
The crystal form is Χ-type, Χ-type, etc., and α-type or ε-type is preferable. Furthermore, unstable or semi-unstable phthalocyanine as a mixed crystal of phthalocyanine and a derivative such as nitrated phthalocyanine or sulfonated phthalocyanine may be used. As the phthalocyanine derivative according to the present invention, any phthalocyanine derivative that stabilizes the crystal of the phthalocyanine optical semiconductor can be used. Phthalocyanine derivatives are phthalonitrile, which is a raw material for phthalocyanine, during phthalocyanine synthesis.
Using phthalic acid, phthalic anhydride, phthalimide, etc., which have a benzene nucleus with a substituent,
Substituents can be introduced by synthesis or later modification of phthalocyanine. Examples of phthalocyanine derivatives include phthalocyanine derivatives represented by the following general formula.

[Formula] (In the formula, Pc is a phthalocyanine residue, Χ is a halogen atom, a nitro group, an alkoxy group, a phenoxy group, a substituted or unsubstituted phenylcarbamoyl group having 1 to 20 carbon atoms, or a phenylsulfamoyl group) Indicates any substituent, Y is as shown below (a)
-(f) etc., m is 0-2,
n is 0 to 4, and m+n=1 to 6.

embedded image R ₁ and R ₂ each represent a hydrogen atom, a substituted or unsubstituted alkyl group, or R ₁ and R ₂ together form a heterocycle containing at least a nitrogen atom.

embedded image R ₃ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a nitro group.

[Chemical formula] R ₄ is a hydrogen atom, a substituted or unsubstituted alkyl group, R ₅ is a substituted or unsubstituted alkylene group or arylene group, R ₆ and R ₇ are each a hydrogen atom, a substituted or unsubstituted alkyl group, or Indicates that R ₆ and R ₇ form a heterocycle containing at least a nitrogen atom. (d)-SO ₃ M ₁ M ₁ represents an alkali metal or an alkaline earth metal.

[Chemical formula] R ₈ is a hydrogen atom, a substituted or unsubstituted alkyl group, R ₉ is a substituted or unsubstituted alkylene group or arylene group, R ₁₀ and R ₁₁ are each a hydrogen atom,
Substituted or unsubstituted alkyl group, or R ₁₀ and
Indicates that a heterocycle containing at least a nitrogen atom is formed with R ₁₁ . (f)-COOM ₂ M ₂ represents an alkali metal or an alkaline earth metal. ) The above-mentioned phthalocyanine derivatives are just one example, and the present invention is not limited thereto, and any derivative that stabilizes the particles of the phthalocyanine photoderivative can be used. In addition, the phthalocyanine of the phthalocyanine derivative includes metal-free phthalocyanine or copper, iron, cobalt, nickel, magnesium, calcium,
Metal phthalocyanines such as sodium, lithium, and aluminum. The composition ratio of the unstable or semi-unstable phthalocyanine photosemiconductor and the phthalocyanine derivative of the present invention is as follows:
The phthalocyanine derivative is 0.001 to 40 parts by weight.
If it is less than 0.001 part by weight, sufficient disaggregation or crystal stability will not be obtained, and sensitivity will also be poor.
If it exceeds parts by weight, the dark decay rate will increase and it cannot be put to practical use. The optical semiconductor material of the present invention only needs to be a mixture of an unstable or semi-unstable phthalocyanine optical semiconductor and a phthalocyanine derivative in a practically uniform state. It is industrially known that the optical semiconductor material obtained by the above-mentioned mixing method has excellent storage stability and that the electrophotographic photoreceptor obtained from this optical semiconductor material has good electrophotographic properties. This is extremely advantageous. Electrophotographic properties such as photosensitivity and stability of sensitivity with repetition may vary depending on the type and amount of phthalocyanine derivatives, but with an appropriate combination, photosensitivity etc. comparable to those of photosemiconductor materials such as cadmium sulfide can be obtained. Furthermore, even higher light resistance can be obtained. The optical semiconductor material of the present invention may be used alone as it is to form a photosensitive layer together with a binder resin or the like. moreover,
Depending on the case, it is also possible to use other phthalocyanine-based optical semiconductor materials, other optical semiconductor materials, and ordinary sensitizers in combination. It may also be a photosensitive layer using a vapor deposition method. Furthermore, the optical semiconductor material according to the present invention can be used in combination with compounds such as hydrazone-based, oxadiazole-based, triphenylmethane-based, pyrazolone-based, styryl-based, etc., which are known as charge transfer materials, in a single layer or in a laminated manner. It can also be used as a functionally separated type. Furthermore, if necessary, 0.01 to 30 parts by weight of an antioxidant can be used in combination with 100 parts by weight of phthalocyanine. In order to use the optical semiconductor material of the present invention as an electrophotographic photoreceptor, it is uniformly dispersed together with a binder resin, a solvent, etc. using a kneading and dispersing machine such as a ball mill or attritor, and coated on a conductive support. Form a photosensitive layer. Note that electrophotographic photoreceptors using the photosemiconductor material of the present invention include not only electrophotographic photoreceptors with only the photosensitive layer according to the invention, but also electrophotographic photoreceptors with a barrier layer, an insulating layer, and photosensitive layers of other photosemiconductor materials laminated. It can be a body. Examples of binder resins include melamine resin, epoxy resin, silicone resin, polyurethane resin, polyester resin, acrylic resin, xylene resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate resin, and cellulose derivatives with a volume resistivity of 10. ⁷
A binder resin with insulation properties of Ωcm or more. This photosemiconductor material is applied by coating onto a sheet-like or cylindrical conductive support such as an aluminum plate, conductively treated paper, or plastic film, which is commonly used in electrophotographic photoreceptors, to form a photosensitive layer. As for the coating method, if necessary, add a solvent to the optical semiconductor material to adjust the viscosity, and form a film using an air doctor coater, blade coater, rod coater, reverse roll coater, spray coater, hot coater, squeeze coater, etc. . After coating, appropriate drying is performed until a sufficient charging potential is applied as a photoconductive layer. Further, the photoreceptor according to the present invention usually has a resin/photoconductor element weight ratio of 1 or more, and has a larger amount of resin than a photoreceptor using zinc oxide, for example.
The film has physical strength and is highly flexible. It also has strong adhesion to conductive supports, good moisture resistance, little change over time, and no toxicity problems.
It has excellent practical characteristics such as being easy to manufacture and inexpensive. In addition, when using the electrophotographic photoreceptor using the optical semiconductor material of the present invention, a laser beam can also be used as a light source in addition to a normal halogen lamp or the like. In the above invention, the electrophotographic photoreceptor has been mainly explained, but the optical semiconductor material of the present invention can be used for other purposes,
For example, it can also be used for solar cells, sensors, etc. The present invention will be explained below by giving examples. In the examples, "parts" indicate parts by weight. Example 1 ε-type copper phthalocyanine 1 part 2,5-bis(4-diethylaminophenyl)
-1,3,4-oxadiazole 3 parts Piperidinomethyl copper phthalocyanine 0.01 part Acrylic polyol (Takerak A-702 manufactured by Takeda Pharmaceutical Co., Ltd.) 3.6 parts Epoxy resin (Epon 1007 manufactured by Ciel Chemical Co., Ltd.)
0.5 parts xylene 1.2 parts cellosolve acetate 1.2 parts The above composition was kneaded in a magnetic ball mill for 48 hours to obtain a photoconductive composition. Immediately after production, after one month, and after three months, the resulting photoconductive composition was checked for storage stability and coated to examine its electrophotographic properties. The storage stability was good, with no aggregation of phthalocyanine observed even after 3 months. In testing the electrophotographic properties, this photoconductive composition was roll coated onto aluminum in a laminate film of 5 μm thick aluminum foil and 75 μm polyester film to a dry film thickness of 8 μm.
It was placed in an oven uniformly heated to 110° C. for 1 hour to prepare an electrophotographic photoreceptor. A corona discharge was applied to each sample thus obtained at +5.7 KV, a corona gap of 10 mm, and a charging speed of 10 m/min, and 10 seconds after the discharge stopped, the sample was exposed to light at an illuminance of 10 Lux using a 2854°K tungsten light source. The amount of light irradiation required for the potential immediately before exposure to decrease by 50% at this time was defined as the sensitivity. The maximum surface charge, dark decay rate, sensitivity, and residual potential of the sample measured in this way were as shown in the table below.
Both chargeability and sensitivity were values sufficient for practical use.

[Table] Furthermore, this sample was repeatedly charged and exposed to light, and changes in sensitivity were measured. As a result, it was found to be a photoreceptor with excellent repeat stability, and exhibited a photosensitivity comparable to that of a cadmium sulfide photoreceptor. In addition, by positively charging the photoreceptor, exposing it to white light with a positive image test pattern, and developing it with negatively charged developing toner, the exposure amount is 6 to 7 Lux sec, which is faithful to the test pattern, and provides clear contrast. An excellent image was obtained. Comparative Example 1 A photoconductive composition was prepared without using the phthalocyanine derivative in the photoconductive composition of Example 1,
When tested in the same manner as in Example 1, it was found that immediately after production, it was slightly inferior compared to immediately after production in Example 1, and there was no significant difference compared to Example 1, but after one month, aggregation of phthalocyanine was observed. , a crystal transition to the β type was observed, and the sensitivity was 20 Lux·sec. Examples 2 to 3 The ε-type copper phthalocyanine and phthalocyanine derivative of Example 1 were replaced with the phthalocyanine and phthalocyanine derivative shown in the table below to prepare an electrophotographic photoreceptor, and the maximum surface charge amount, dark decay rate, sensitivity, and residual potential were determined in the same manner. was measured.

【table】

[Table] (Cupc and NiPc are copper and nickel phthalocyanine residues, and the numbers outside the brackets indicate the average number of substitutions based on analysis.)

[Table] (The upper row shows Example 2, and the lower row shows Example 3.) Example 5 40 parts of copper phthalocyanine and 0.5 parts of tetranitrocopper phthalocyanine are dissolved in 500 parts of 98% concentrated sulfuric acid with thorough stirring. The dissolved solution is poured into 5000 parts of water to precipitate the phthalocyanine composition, which is then filtered, washed with water, and dried at 120°C under reduced pressure. X-ray diffraction analysis of the resulting composition revealed that it had an α-type crystal structure. Next, 1 part of this composition, 2.5 parts of PN-diethylaminobenzaldehyde-N,N-diphenylhydrazone, 1 part of piperidinosulfonamide copper phthalocyanine, 3.6 parts of Takerac A-702, 0.5 parts of Epon 1007, and 1.2 parts of methyl ethyl ketone. When a composition consisting of 1.2 parts of cellosolve acetate and 1.2 parts of cellosolve acetate was made into a photoelectric composition in the same manner as in Example 1, no change was observed even after 3 months. amount
Good results were obtained at 620V, dark decay rate 4.6%, sensitivity 1.9Luxsec, and residual potential 40V. Comparative Example 2 A photoconductive composition was prepared without using the phthalocyanine derivative in the photoconductive composition of Example 5,
When tested in the same manner as in Example 5, there was almost no change immediately after production, but after 3 months, aggregation of phthalocyanine was observed, crystal transition to the β type was observed, and the sensitivity was 18 Lux·sec, which was approximately 1. /18,
It cannot be said that it is practical. Examples 6 to 7 The phthalocyanine and phthalocyanine derivative of Example 5 were replaced with the phthalocyanine and phthalocyanine derivative shown in the table below to prepare an electrophotographic photoreceptor, and the maximum surface charge amount, dark decay rate, sensitivity, and residual potential were measured in the same manner. .

【table】 The results are shown after 3 months.

[Table] Example 8 Example of a composition consisting of 10 parts of ε-type copper phthalocyanine, 0.1 part of piperidinosulfonamide copper phthalocyanine, 2 parts of polyester resin (Vyoln RV-200 manufactured by Toyobo Co., Ltd.), 40 parts of tetrahydrofuran, and 10 parts of toluene. A charge generation layer was formed by coating in a thickness of 0.5μ in the same manner as in 1. Next, a mixed solution of 10 parts of Vylon RV-200, 10 parts of N-ethylcarbazole-3-carbaldehydemethylphenylhydrazone, and 50 parts of tetrahydrofuran was applied to the charge generation layer to a thickness of about 10 μm.
It was dried at ℃ to obtain a laminated photoreceptor. The electrophotographic properties of the obtained photoreceptor were investigated in an environment with a temperature of 0°C to 45°C and a humidity of 10% to 85%, and the results showed that the maximum surface charge amount was 1200±100V, the dark decay rate was 1.5%, and the sensitivity was 3.6±0.5Luxsec, residual potential 80V
, there were almost no changes, and it was sufficiently usable.

Claims (1)

[Claims] 1 An unstable or semi-unstable crystalline phthalocyanine photosemiconductor having one type of crystalline form selected from α-type and ε-type, and a phthalocyanine derivative that stabilizes the phthalocyanine crystal against organic solvents. Optical semiconductor materials.