JPH07324059A - Benzidine derivative and electrophotographic sensitizer using the same - Google Patents

Abstract

PURPOSE:To obtain the new compound maintaining a high positive electron hole-transporting ability, capable of improving the durability, heat resistance, etc., of a film containing the compound because of having a high melting point and being excellent in compatibility with binding resins, and suitable as a positive electron hole-transporting material. CONSTITUTION:A compound of formula I (R<1>,R<2> are H, alkyl; R<3>,R<4> are alkyl, halogen, etc.; R<5>,R<6> are 3-5C alkyl, aryl; m, n are 2, 3), e.g. N,N'-bis(3,4- dimethylphenyl)-N,N'-bis(4-n-butylphenyl)-3,3'-dimethylbenzidine. The compound is obtained, e.g. by reacting N,N'-diacetyl-3,3'-dimethylbenzidine with 3,4-dimethyl iodobenzene of formula III in a molar ratio of 1:2 in the presence of copper powder and a basic substance, deacetylating the product in the presence of an amide-decomposing catalyst such as an acid, and subsequently reacting the obtained compound of formula IV with 4-n-butyl iodobenzene in a molar ratio of 1:2.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel benzidine derivative which is preferably used as a charge transporting material, particularly a hole transporting material in, for example, solar cells, electroluminescent devices, electrophotographic photoreceptors and the like. The electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Various organic compounds such as carbazole compounds, oxadiazole compounds, pyrazoline compounds, hydrazone compounds, stilbene compounds, phenylenediamine compounds and benzidine compounds are known as charge transport materials. ing. These charge transport materials are usually used in a state of being dispersed in a film made of a suitable binder resin. For example, in the case of an electrophotographic photoreceptor, a single-layer type photoreceptor having a single-layer type photosensitive layer in which the above charge transport material is dispersed in a binder resin together with a charge generating material that generates charges by light irradiation, A so-called organic photoreceptor (OPC) such as a laminated photoreceptor having a charge transport layer containing a charge transport material and a charge generation layer containing a charge generation material is often used. Such an organic photoreceptor has the advantages that it has good workability, is easy to manufacture, and has a high degree of freedom in functional design.

Among these compounds, the following general formula, which belongs to the benzidine-based compounds:

[0004]

[Chemical 9]

[In the formula, R ^a , R ^b , R ^c and R ^d are the same or different and each represents a hydrogen atom, a lower alkyl group, a lower alkoxy group or a chlorine atom. ] 3,3'- represented by
The dimethylbenzidine derivative has a high hole-transporting ability and is also excellent in compatibility with the binder resin, and thus is preferably used as a hole-transporting material (Japanese Patent Publication No.
No. 21099).

[0006]

[Problems to be Solved by the Invention]
Since the 3'-dimethylbenzidine derivative generally has a low melting point (about 180 ° C or lower), the film obtained by dispersing it in a binder resin has a low glass transition temperature (Tg), and has poor durability and heat resistance. There is a problem that it will be enough. In the case of electrophotographic photoreceptors, charging of the photoreceptor surface by corona discharge, formation of electrostatic latent image by exposure, visualization of electrostatic latent image by adhesion of toner, transfer of toner image to paper, exposure after transfer Each step of removing the toner remaining on the body surface is repeated. A cleaning blade pressed against the surface of the photoconductor is used to remove the toner. Therefore, in the conventional photoconductor using the benzidine derivative, when the image forming apparatus is stopped, a pressure contact mark is generated in a portion where the cleaning blade is pressure contacted, which causes various image defects. Further, during operation of the image forming apparatus, the temperature inside the apparatus rises to about 50 ° C., so that a dent is formed on the surface of the photoconductor, which also causes various image defects.

The main object of the present invention is to maintain a high hole transporting ability and to have excellent compatibility with the binder resin, and to improve the durability and heat resistance of the film formed by dispersing the binder resin in the binder resin. It is to provide an improved novel benzidine derivative. Another object of the present invention is to provide a high-performance electrophotographic photosensitive member which uses the above-mentioned benzidine derivative as a hole transport material and which has high sensitivity and is excellent in durability and heat resistance.

[0008]

Means and Actions for Solving the Problems In order to solve the above-mentioned problems, the inventors studied to raise the melting point of the benzidine derivative, and designed the molecule in accordance with the policy. As a result, it was found that the melting point of the benzidine derivative can be increased while maintaining the high hole transporting ability and the good compatibility with the binder resin if at least one of the following conditions is satisfied, and the present invention is completed. I arrived. Substitution of two or three alkyl groups in at least two of the four phenyl groups on the outside of the benzidine derivative. Of the four phenyl groups on the outside of the benzidine derivative, two phenyl groups should be substituted with a linear or branched alkyl group having 3 to 5 carbon atoms. Introduce a substituent such as an alkyl group at the 3,3'-position and the 5,5'-position of biphenyl, which is the central skeleton of the benzidine derivative. Introducing a substituent such as an alkyl group at the 2,2'-position and the 5,5'-position of biphenyl, which is the central skeleton of the benzidine derivative. A phenyl group is bonded to the para-position of two or four phenyl groups outside the benzidine derivative to form a biphenylyl group, and the π-electron conjugated system has a spatial extent.

That is, the benzidine derivative of the present invention is
It is represented by the following general formulas (1) to (5). I. General formula (1):

[0010]

[Chemical 10]

[Wherein R ¹ and R ² are the same or different and each represents a hydrogen atom or an alkyl group, and R ³ and R ⁴
Are the same or different and represent an alkyl group, an alkoxy group or a halogen atom, and R ⁵ and R ⁶ are the same or different and represent an alkyl group having 3 to 5 carbon atoms or an aryl group which may have a substituent. m and n are the same or different and represent 2 or 3. ) Preferably, the general formula (1 ′):

[0012]

[Chemical 11]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ ,
m and n are the same as above. ) II. General formula (2):

[0014]

[Chemical 12]

(Wherein R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ ,
R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are the same or different and each represents an alkyl group, an alkoxy group or a halogen atom. ) III. General formula (3):

[0016]

[Chemical 13]

(Wherein R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are the same or different and represent an alkyl group or an alkoxy group, and R ²¹ and R ²² are the same or different and are a hydrogen atom, an alkyl group, an alkoxy group or Indicates a halogen atom, R
²³ and R ²⁴ are the same or different and each represents a hydrogen atom, an alkyl group or an aryl group which may have a substituent. ) Preferably, the general formula (3 ′):

[0018]

[Chemical 14]

(Wherein R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are the same as defined above, R ²⁵ and R ²⁶ are the same or different and represent a hydrogen atom or an alkyl group, and R ²⁷ and R ²⁸ are the same or different. Represents an alkyl group having 3 to 5 carbon atoms or an aryl group which may have a substituent.) IV. General formula (4):

[0020]

[Chemical 15]

(Wherein R ²⁹ , R ³⁰ , R ³¹ and R ³² are the same or different and represent an alkyl group or an alkoxy group, R ³³ and R ³⁴ are the same or different and are an alkyl group,
An alkoxy group or a halogen atom, R ³⁵ and R
³⁶ are the same or different and each represents an alkyl group having 3 to 5 carbon atoms. ) V. General formula (5):

[0022]

[Chemical 16]

(In the formula, R ³⁷ , R ³⁸ , R ³⁹ and R ⁴⁰ are the same or different and each represents a hydrogen atom or an alkyl group;
⁴¹ and R ⁴² are the same or different and each represents an alkyl group. The electrophotographic photosensitive member of the present invention is provided with a photosensitive layer containing, on a conductive substrate, at least one of the benzidine derivatives represented by the general formulas (1) to (5) as a hole transport material. .

Another electrophotographic photosensitive member of the present invention has a single-layer photosensitive layer provided on a conductive substrate and has the following general formula:
A positive charging type photoreceptor having a single-layer photosensitive layer containing the benzidine derivative represented by (6) as a hole transport material.

[0025]

[Chemical 17]

(In the formula, R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ are the same or different and each is a hydrogen atom, an alkyl group,
An alkoxy group or a halogen atom is shown. The present invention will be described in detail below. The above general formula (1),
The groups R ⁵ , R ⁶ , R ²⁷ , R ²⁸ and R ^{35 in} (3 ′) and (4)
And the carbon number of the alkyl group represented by R ³⁶ is limited to 3 to 5 as described above. When the alkyl group has less than 3 carbon atoms, good compatibility with the binder resin cannot be ensured. When the carbon number of the alkyl group exceeds 5,
It hinders the hole transport ability.

Examples of the alkyl group having 3 to 5 carbon atoms include propyl group (n-Pr) and isopropyl group (i-P).
r), butyl group (n-Bu), isobutyl group (i-B)
u), tert-butyl group (t-Bu), pentyl group and other linear or branched alkyl groups. Other alkyl groups having no particular limitation on the number of carbon atoms include, for example, methyl group, ethyl group, propyl group, isopropyl group,
Examples thereof include lower alkyl groups having 1 to 6 carbon atoms such as a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group, with a methyl group or an ethyl group being particularly preferred.

M, n which defines the number of substituents in the general formula (1)
Is limited to 2 or 3 as described above. When the number of substituents of R ³ and R ⁴ is 1, the melting point of the benzidine derivative cannot be improved, and when the number of substituents is 4 or more, good compatibility with the binder resin cannot be secured. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a tert-butoxy group, a pentyloxy group, a hexyloxy group, or a straight chain having 1 to 6 carbon atoms or Examples include branched alkoxy groups.

Examples of the aryl group include a phenyl group, a tolyl group, a naphthyl group, a biphenyl group, an anthryl group and a phenanthryl group. Examples of the substituent that may be substituted on the aryl group include an alkyl group, an alkoxy group, a halogen atom and the like. Examples of the halogen atom include chlorine, bromine, iodine and fluorine.

Examples of the benzidine derivative represented by the general formula (1) include compounds represented by the following formulas (1-a) to (1-j).

[0031]

[Chemical 18]

[0032]

[Chemical 19]

[0033]

[Chemical 20]

Examples of the benzidine derivative represented by the general formula (2) include compounds represented by the following formulas (2-a) to (2-f).

[0035]

[Chemical 21]

[0036]

[Chemical formula 22]

As the benzidine derivative represented by the general formula (3), there is also a symmetric compound in which the groups R ^{21 to} R ²⁴ are the same and the substitution positions are the same, and the groups R ^{17 to} R ²⁰ are the same. Included, compatibility with the binder resin, charge transport ability, etc.
Considering the performance as a charge transport material, an asymmetric compound is more preferable. The asymmetric compound as used herein means a compound satisfying at least one of the following: groups R ^{21 to} R ²⁴ are different, groups R ^{21 to} R ²⁴ are different in substitution position, and groups R ^{17 to} R ²⁰ are different. However, those satisfying the condition that the groups R ^{21 to} R ²⁴ are different from each other are particularly preferable from the viewpoint of performance as the hole transport material and the ease of production.

As a specific example of the above-mentioned asymmetric type benzidine derivative, all the groups R ^{17 to} R ²⁰ are methyl groups, and all the groups R ^{21 to} R ²⁴ are substituted at the 4-position of the phenyl group, Among them, compounds in which the groups R ²¹ and R ²² are hydrogen atoms or the same alkyl groups and the groups R ²³ and R ²⁴ are the same alkyl groups and are different from the above groups R ²¹ and R ²² are mentioned. Specific examples of the benzidine derivative represented by the general formula (3) include compounds represented by the following formulas (3-a) to (3-c). As is clear from these formulas, compounds in which the groups R ²¹ and R ²² are hydrogen atoms and the groups R ²³ and R ²⁴ are alkyl groups such as a methyl group, or the groups R ²¹ and R ²² are methyl groups, Examples thereof include compounds in which the groups R ²³ and R ²⁴ are alkyl groups having 2 or more carbon atoms, such as tert-butyl group and n-butyl group. In particular, considering the charge transport ability and the compatibility with the binder resin, the group R
^{21 to} R ²⁴ are all alkyl groups, and the groups R ²¹ and R ^{22 are}
The larger the difference in the number of carbon atoms between the alkyl group of and the alkyl groups of R ²³ and R ²⁴ , the more preferable. In addition, in formula (3-c), -C ₄ H ₉
Represents an n-butyl group.

[0039]

[Chemical formula 23]

Considering these conditions, N, N'-di (4-methylphenyl) -N, N 'represented by the formula (3-b):
-Di (4-tert-butylphenyl) -3,3 ', 5
5'-Tetramethylbenzidine is mentioned as the most preferred benzidine derivative. Further, as another specific example of the benzidine derivative represented by the general formula (3), the following formula (3
Examples thereof include compounds represented by -d) to (3-f).

[0041]

[Chemical formula 24]

Examples of the benzidine derivative represented by the general formula (4) include compounds represented by the following formulas (4-a) and (4-b).

[0043]

[Chemical 25]

Examples of the benzidine derivative represented by the general formula (5) include compounds represented by the following formulas (5-a) to (5-c).

[0045]

[Chemical formula 26]

[0046]

[Chemical 27]

In the benzidine derivative represented by the general formula (6), in the phenyl group bonded to the nitrogen atom of the benzidine skeleton, the groups R ⁴⁵ and R ⁴⁶ are preferably substituted at the 4-position (para position). . Further, in the biphenylyl group, the nitrogen atom can be bonded to any position of 2'to 4'position, but it is preferably bonded to 4'position. The groups R ⁴⁷ and R ⁴⁸ for substituting the biphenylyl group are 2 to 4 of the biphenylyl group.
Although it can be bonded to the 6-position, it is preferably bonded to the 4-position.

The benzidine derivative of the present invention can be synthesized by various methods. For example, the benzidine derivative of the above formula (1-a) can be synthesized according to the following reaction process formula. First, N, N′− represented by the following equation (7)
Diacetyl-3,3'-dimethylbenzidine and the formula (8)
3,4-dimethyliodobenzene represented by the following formula is mixed with copper powder, copper oxide, copper halide, or the like in a molar ratio of 1: 2, and reacted in the presence of a basic substance. N, N'-diacetyl-N, N 'represented by (9)
-Bis (3,4-dimethylphenyl) -3,3'-dimethylbenzidine is obtained.

[0049]

[Chemical 28]

Next, N, N'-diacetyl-N, N'-bis (3,4-dimethylphenyl) -3, of the above formula (9),
3'-Dimethylbenzidine is subjected to a deacetylation reaction in the presence of an amide decomposition catalyst such as an acid to give N, N'-bis (3,4-dimethylphenyl) -3, represented by the following formula (10):
When 3'-dimethylbenzidine is obtained and reacted with 4-n-butyliodobenzene represented by the formula (11) at a molar ratio of 1: 2 by the same method as described above, the compound of the formula (1
-The benzidine derivative of a) is synthesized.

[0051]

[Chemical 29]

Further, the benzidine derivative of the present invention can be synthesized by the following reaction process formula instead of the above synthesis method. The following reaction schemes illustrate the method for synthesizing the benzidine derivative of formula (1-d). First, the following formula
4,4′-diiodobiphenyl represented by (7 ′) and a formula
P-Isopropylacetanilide represented by (8 ') is mixed with copper powder, copper oxide, copper halide or the like in a molar ratio of 1: 2 and reacted in the presence of a basic substance, N, N'-diacetyl-N, N'-bis (4-isopropylphenyl) benzidine represented by the formula (9 ') is obtained.

[0053]

[Chemical 30]

Next, the N, N'-diacetyl-N, N'-bis (4-isopropylphenyl) benzidine of the above formula (9 ') is subjected to a deacetylation reaction to be represented by the following formula (10'). N, N'-bis (4-isopropylphenyl) benzidine is obtained, which is represented by the formula (11 ')
With dimethyl iodobenzene in a molar ratio of 1: 2,
By reacting in the same manner as above, the benzidine derivative of the formula (1-d) is synthesized.

[0055]

[Chemical 31]

As described above, the benzidine derivative of the present invention is suitably used as a charge transporting material for solar cells, electroluminescent devices, electrophotographic photoreceptors, etc., especially as a hole transporting material, and various other materials. It can be used in the field. The electrophotographic photoreceptor of the present invention comprises a conductive substrate and a photosensitive layer containing one or more of the benzidine derivatives represented by the general formulas (1) to (6). The photosensitive layer is classified into a so-called single layer type and a laminated type, but the constitution of the present invention can be applied to any of these.
However, the benzidine derivative represented by the general formula (6) is used only for a single-layer photoreceptor.

To obtain a single-layer type photosensitive layer, one of the general formula (1)
At least one of the benzidine derivatives represented by (6) is used as a hole transport material, and a coating solution prepared by dissolving or dispersing it in a suitable solvent together with a charge generating material, a binder resin, etc. is applied on a conductive substrate by means such as coating. It can be applied to and dried.
To obtain a laminated type photosensitive layer, first, on a conductive substrate,
A charge generation layer containing a charge generation material is formed by means such as vapor deposition or coating, and then, on this charge generation layer,
The charge transport layer may be formed by applying a coating solution containing at least one of the benzidine derivatives represented by the general formulas (1) to (5) and a binder resin by means such as coating and drying. In contrast to the above, a charge transport layer may be formed on the conductive substrate, and the charge generation layer may be formed thereon.

As the charge generating material, for example, selenium,
Selenium-tellurium, selenium-arsenic, cadmium sulfide, α-
Powder of inorganic photoconductive material such as silicon, azo pigment, perylene pigment, anthanthrone pigment, phthalocyanine pigment, indigo pigment, triphenylmethane pigment, slene pigment, toluidine pigment, pyrazoline pigment, quinacridone Examples thereof include, but are not limited to, pigments and dithioketopyrrolopyrrole pigments. These charge generating materials may be used alone or in combination of two or more, depending on the sensitivity region of the electrophotographic photosensitive member.

The benzidine derivatives represented by the general formulas (1) to (6) which are hole transporting materials can be used alone or in combination with other conventionally known charge transporting materials. Other charge transport materials include various electron transport materials and hole transport materials.

Examples of the electron transport material include diphenoquinone compounds, benzoquinone compounds, naphthoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromoanil, 2,4,7-trinitro-. 9-
Fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,7-trinitro-9-dicyanomethylenefluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitro Electron withdrawing materials such as thioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, and dibromomaleic anhydride, and polymerized materials of these electron withdrawing materials are available. can give.

As the hole transport material, for example,
Diamine compounds other than the benzidine derivatives represented by the general formulas (1) to (6), diazole compounds such as 2,5-bis (4-methylaminophenyl) -1,3,4-oxadiazole, 9 A styryl compound such as-(4-diethylaminostyryl) anthracene, a carbazole compound such as polyvinylcarbazole, 1-phenyl-3- (p-
Pyrazoline compounds such as dimethylaminophenyl) pyrazolin, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, Examples thereof include electron-donating materials such as nitrogen-containing cyclic compounds represented by triazole compounds and condensed polycyclic compounds.

When using a charge transporting material having a film forming property such as polyvinylcarbazole, the binder resin is not always necessary. Examples of the binder resin include styrene polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic polymers, styrene-acrylic copolymers, polyethylene, ethylene. -Vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl Thermoplastic resin such as butyral resin and polyether resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin and other crosslinkable thermosetting resin, further epoxy-acrylate, urethane-acrylate Etc. of the photocurable resin. These binder resins can be used alone or in combination of two or more.

In addition to the above components, various additives such as sensitizers, fluorene compounds, antioxidants, ultraviolet absorbers, plasticizers, interfacial lubricants, leveling agents and the like are added to the photosensitive layer. You can also do it. Further, in order to improve the sensitivity of the photoconductor, a sensitizer such as terphenyl, halonaphthoquinones and acenaphthylene may be used in combination with the charge generating material.

In the laminated photoreceptor, the charge generating material and the binder resin constituting the charge generating layer can be used in various ratios, but the charge generating material 5 to 5 parts by weight relative to 100 parts by weight of the binder resin. It is preferably used in an amount of 1000 parts by weight, particularly 30 to 500 parts by weight. The hole-transporting material and the binder resin constituting the charge-transporting layer can be used in various proportions within a range that does not hinder the transport of charges and a range that does not crystallize. 10 to 500 parts by weight, particularly 25 to 50 parts by weight of the hole transport material containing the benzidine derivative represented by the general formulas (1) to (5), based on 100 parts by weight of the binder resin so that the electric charge can be easily transported. ~
It is preferably used in a proportion of 200 parts by weight.

The thickness of the laminated photosensitive layer is preferably 0.01 to 5 μm, particularly 0.1 to 3 μm for the charge generation layer, and 2 to 100 μm for the charge transport layer.
It is preferable that it is formed to a thickness of m, especially about 5 to 50 μm. In the single-layer type photoreceptor, the charge generating material is 0.1 to 50 parts by weight, particularly 0.5 to 30 parts by weight, based on 100 parts by weight of the binder resin, and the charge generation material is represented by the general formula (1) to (6) The hole transporting material containing the benzidine derivative is suitably 10 to 500 parts by weight, particularly 25 to 200 parts by weight.
When an electron transport material is also used, the binder resin 100
It is preferable to use the electron transport material in an amount of 5 to 100 parts by weight, particularly 10 to 80 parts by weight based on parts by weight. Further, the total amount of the hole transport material and the electron transport material is the binder resin 1
20 to 500 parts by weight, especially 30 to 100 parts by weight
200 parts by weight is preferred.

In the case of a single-layer type photoreceptor, between the conductive substrate and the photosensitive layer, in the case of the laminated type photoreceptor, between the conductive substrate and the charge generating layer, and between the conductive substrate. A barrier layer (undercoat layer) may be formed between the charge transport layer and between the charge generation layer and the charge transport layer as long as the characteristics of the photoreceptor are not impaired. A protective layer may be formed.

As the conductive substrate on which the above layers are formed, various conductive materials can be used.
For example, aluminum, copper, tin, platinum, silver, iron, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass or other metal simple substance, a plastic material in which the above metal is vapor-deposited or laminated, Aluminum iodide, tin oxide,
Examples thereof include glass coated with indium oxide or the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the conductive substrate has sufficient mechanical strength when used. When each of the above layers is formed by a coating method, the charge generation material, charge transport material, and
The binder resin and the like are dispersed and mixed together with an appropriate solvent by a known method, for example, using a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser or the like to prepare a coating solution, which is prepared by a known means. It may be applied and dried.

As the solvent for forming the coating liquid, various organic solvents can be used. For example, alcohols such as methanol, ethanol, isopropanol and butanol, and aliphatic hydrocarbons such as n-hexane, octane and cyclohexane. , Aromatic hydrocarbons such as benzene, toluene, xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone , Ketones such as cyclohexanone, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide and the like. . These solvents are 1 type or 2 types.
A mixture of two or more species can be used.

Further, in order to improve the dispersibility of the charge transport material or the charge generating material and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent, etc. may be used.

[0071]

EXAMPLES The present invention will be described below with reference to synthesis examples, examples and comparative examples. Synthesis Example 1 N, N'-diacetyl-3,3'-dimethylbenzidine 14.8 g and 3,4-dimethyliodobenzene 23.
2 g and 13.8 g of potassium carbonate and 1 g of copper powder were added to 150 ml of nitrobenzene, and while stirring vigorously, blowing nitrogen gas into the reaction system 24
Reflux for hours. Water generated during the reaction was azeotropically distilled with nitrobenzene and taken out of the reaction system.

After cooling the reaction solution, the inorganic substances were filtered off, and the residue obtained by distilling off nitrobenzene by steam distillation was used.
This was added to 100 ml of tetrahydrofuran together with 10% hydrochloric acid and refluxed for 2 hours for deacetylation to obtain N, N'-bis (3,4-dimethylphenyl) -3,3'-dimethylbenzidine. This N, N′-bis (3,4-dimethylphenyl) -3,3′-dimethylbenzidine 10.
5 g and 13.0 g of 4-n-butyliodobenzene were added to 150 ml of nitrobenzene together with 13.8 g of potassium carbonate and 1 g of copper powder, and while stirring strongly, nitrogen gas was blown into the reaction system. 24 hours,
Refluxed. Moisture produced during the reaction was azeotroped with nitrobenzene and taken out of the reaction system as in the previous case.

After cooling the reaction solution, the inorganic substances were filtered off, and the residue obtained by distilling off nitrobenzene by steam distillation was dissolved in cyclohexane and separated and purified by silica gel column chromatography to remove the cyclohexane to obtain a white precipitate. It was The white precipitate was recrystallized using n-hexane to obtain the desired product, N, N'-bis (3,4-dimethylphenyl) -N, represented by the formula (1-a).
N'-bis (4-n-butylphenyl) -3,3'-dimethylbenzidine was obtained. The yield was 8.7 g (27.
3%).

The result of infrared spectroscopic analysis of the product is shown in FIG. Elemental analysis result Calculated value (%) C: 87.65 H: 8.26 N:
4.09 measured value (%) C: 87.60 H: 8.24 N:
4.14 Melting point: 180.6 ° C Synthesis example 2 23.2 g of 2,4-dimethyliodobenzene was used in place of 3,4-dimethyliodobenzene, and 4-n
In the same manner as in Synthesis Example 1, except that 12.3 g of 4-isopropyliodobenzene was used instead of -butyliodobenzene, N, N'-bis (2,4) represented by the above formula (1-b) -Dimethylphenyl) -N, N'-bis (4-
Isopropylphenyl) -3,3'-dimethylbenzidine was obtained. The yield was 8.4 g (yield 27.2%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 87.74 H: 7.99 N:
4.26 Found (%) C: 87.70 H: 7.97 N:
4.31 Melting point: 182.6 ° C. Synthesis example 3 Using the appropriate starting materials in the same manner as in Synthesis example 1, the above formula was used.
A compound represented by (1-c) was obtained. Melting point: 181.9 [deg.] C. Synthesis example 4 4,4'-diiodobiphenyl 20.3 g and p-isopropylacetanilide 21.3 g in 150 ml of nitrobenzene together with 13.8 g of potassium carbonate and 1 g of copper powder. In addition, the mixture was refluxed for 24 hours while blowing nitrogen gas into the reaction system while vigorously stirring. Water generated during the reaction was azeotropically distilled with nitrobenzene and taken out of the reaction system.

After cooling the reaction solution, inorganic substances were filtered off, and the residue obtained by distilling nitrobenzene off by steam distillation
The mixture was added to 100 ml of tetrahydrofuran with 10% hydrochloric acid and refluxed for 2 hours to obtain N, N'-bis (4-isopropylphenyl) benzidine. Next, this N, N '
-Bis (4-isopropylphenyl) benzidine 10.
5g and 11.6g of 2,4-dimethyliodobenzene were added to 150ml of nitrobenzene together with 13.8g of potassium carbonate and 1g of copper powder, and while stirring vigorously, blowing nitrogen gas into this reaction system. Refluxed for 24 hours. The water generated during the reaction was azeotropically distilled with nitrobenzene and taken out of the reaction system in the same manner as described above.

Next, after cooling the reaction solution, the inorganic substances are filtered off,
Further, the residue obtained by distilling off nitrobenzene by steam distillation was dissolved in cyclohexane, separated and purified by silica gel column chromatography, and cyclohexane was distilled off to obtain a white precipitate. The white precipitate was recrystallized from n-hexane to give N, N'-bis (2,4-dimethylphenyl) -N, represented by the formula (1-d).
N'-bis (4-isopropylphenyl) benzidine was obtained. The yield was 8.3 g (yield 29.0%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 87.84 H: 7.71 N:
4.45 Measured value (%) C: 87.83 H: 7.66 N:
4.50 Melting point: 187.6 ° C. Synthesis Examples 5 and 6 Using the appropriate starting materials in the same manner as in Synthesis Example 4, the above formula was used.
The compounds represented by (1-e) and (1-f) were obtained, respectively.

Melting point of compound of formula (1-e): 185.4 ° C. Melting point of compound of formula (1-f): 183.9 ° C. Synthesis example 7 N, N′-diacetyl-3,3′-dimethylbenzidine 14.8 g and 2,4-dimethyliodobenzene 23.
2g was reacted in the same manner as in Example 1 to give N, N'-
Bis (2,4-dimethylphenyl) -3,3'-dimethylbenzidine was obtained. This N, N'-bis (2,4-dimethylphenyl) -3,3'-dimethylbenzidine 1
0.5 g, 4-ethyl-4'-iodobiphenyl 1
5.4 g was reacted in the same manner as in Example 1 to give the above formula (1-
g) N, N'-bis (2,4-dimethylphenyl) -N, N'-bis (4'-ethylbiphenyl-4)
-Yl) -3,3'-dimethylbenzidine was obtained. The yield was 7.8 g (yield 21.3%).

The result of infrared spectroscopic analysis of the product is shown in FIG. Elemental analysis result Calculated value (%) C: 89.17 H: 7.24 N:
3.59 measured value (%) C: 88.98 H: 7.22 N:
3.78 Melting point: 204.4 ° C Synthesis example 8 The same formula (3) was used except that 23.2 g of 3,4-dimethyliodobenzene was used instead of 2,4-dimethyliodobenzene. N-N 'represented by 1-h)
-Bis (3,4-dimethylphenyl) -N, N'-bis (4'-ethylbiphenyl-4-yl) -3,3'-dimethylbenzidine was obtained. The yield was 7.9 g (22.
1%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 89.17 H: 7.24 N:
3.59 Measured value (%) C: 88.94 H: 7.21 N:
3.83 Melting point: 236.3 ° C. Synthesis Examples 9 and 10 Using the appropriate starting materials in the same manner as in Synthesis Example 7, the above formula was used.
The compounds represented by (1-i) and (1-j) were obtained, respectively.

Melting point of compound of formula (1-i): 218.4 ° C. Melting point of compound of formula (1-j): 237.2 ° C. Examples 1-10, Comparative Examples 1-7 (single layer for digital light source) Type photoreceptor) 5 parts by weight of X-type metal-free phthalocyanine as a charge generating material, 50 parts by weight of a benzidine derivative as a hole transporting material (HTM), and formula (12) as an electron transporting material:

[0083]

[Chemical 32]

3,5-dimethyl-3 ', 5' represented by
8 parts by weight of 30 parts by weight of di-tert-butyldiphenoquinone and 100 parts by weight of polycarbonate as a binder resin.
A coating solution for a single-layer type photosensitive layer was prepared by mixing and dispersing with 100 parts by weight of tetrahydrofuran in a ball mill for 50 hours. A single layer type photoreceptor for a digital light source having a single layer type photosensitive layer having a film thickness of 15 to 20 μm, which is obtained by applying the coating solution on an aluminum base tube by a dip coating method and drying with hot air at 100 ° C. for 60 minutes. Was manufactured.

The benzidine derivatives used in Examples 1 to 10 are shown in Table 1 by using the above compound numbers.
The benzidine derivatives represented by the reference numerals (13) to (19) used in Comparative Examples 1 to 7 are the following compounds.

[0086]

[Chemical 33]

[0087]

[Chemical 34]

[0088]

[Chemical 35]

Benzidine derivative (13) used in each comparative example
The melting points of (19) are shown below. (Compound number) (Melting point) (13) 171.0 ° C (14) 195.2 ° C (15) 201.2 ° C (16) 194.3 ° C (17) 193.5 ° C (18) 170.1 ° C ( 19) 135.6 ° C. The following tests were conducted on the single-layer type photoreceptors obtained in the respective examples and comparative examples, and the characteristics were evaluated.

Initial electrical characteristic test (I) An applied voltage was applied to the surface of the photoconductor using a drum sensitivity tester manufactured by GENTEC, and the surface was +
It was charged to 700V. Then, a wavelength of 780 nm (half-value width of 20 nm) and a light intensity of 16 were extracted from the white light of a halogen lamp as an exposure light source using a bandpass filter.
When the surface of the photoconductor is irradiated with monochromatic light of μW / cm ² (irradiation time is 80 msec.), the surface potential is ½, that is, +
The time required to reach 350 V is measured, and the half-exposure amount E
_1/2 (μJ / cm ² ) was calculated. 3 from the start of exposure
30 msec. The surface potential at the time when it passed was measured as the post-exposure potential V _L (V).

Glass transition temperature measurement A photosensitive sample was prepared by peeling off about 5 mg of the photosensitive layer from the photosensitive member, placing it in a dedicated aluminum pan and sealing it. Then, this sample was measured under the following conditions using a differential scanning calorimeter (model number DSC8230D manufactured by Rigaku Denki Co., Ltd.), and from the measurement results, JIS K 7
121 In accordance with “Plastic transition temperature measurement method”,
The extrapolated glass transition onset temperature (Tig) was determined.

Atmosphere gas: Air Temperature rising rate: 20 ° C./min High temperature resistance test Photoreceptor is plain paper facsimile (model LD manufactured by Mita Kogyo Co., Ltd.
C-650) imaging unit, and after the cleaning blade was kept in pressure contact with the surface of the photoconductor at a linear pressure of 1.5 g / mm for 10 days at an ambient temperature of 50 ° C. The surface condition of the layer was measured using a universal surface profilometer (model number SE-3H manufactured by Kosaka Laboratory), and the maximum depth of the recess was recorded. In the table below, <0.3 μm in the dent column indicates that no dent was observed at all because the surface roughness of an ordinary photoconductor having no dent is about 0.5 μm. ing.

The above results are shown in Table 1.

[0094]

[Table 1]

As is apparent from the table, the photoreceptors of each comparative example using the conventional benzidine derivative had a low extrapolation glass transition onset temperature (Tig) and large dents were observed in the high temperature resistance test. The durability and heat resistance were insufficient. On the other hand, in each of the photoconductors of the examples, the half-exposure amount E _1/2 (μJ / cm ² ) is small, and the post-exposure potential V is
_In addition to the low _L (V), the extrapolated glass transition onset temperature (Tig) was higher than that of the comparative example, and no dent was observed in the high temperature resistance test. From this, it is understood that the photoreceptors of the respective examples have excellent durability and heat resistance. Examples 11 to 40, Comparative Examples 8 to 31 (Single layer type photoreceptor for analog light source) Charge generation material (CG
As M), the following formula:

[0096]

[Chemical 36]

5 parts by weight of any of the azo pigments represented by
70 parts by weight of a benzidine derivative as a hole transport material (HTM) and 3,5 represented by the above formula (12) as an electron transport material.
20 parts by weight of dimethyl-3 ′, 5′-di-tert-butyldiphenoquinone and 100 parts by weight of polycarbonate as a binder resin were mixed and dispersed in a ball mill for 50 hours together with 800 parts by weight of tetrahydrofuran,
A coating liquid for a single-layer type photosensitive layer was prepared. This coating solution is applied on an aluminum tube by a dip coating method to obtain 100
It was dried with hot air at 60 ° C. for 60 minutes to produce a single-layer type photoreceptor for analog light source having a single-layer type photosensitive layer having a film thickness of 15 to 20 μm.

The benzidine derivatives used in Examples and Comparative Examples are indicated by the above-mentioned compound numbers. The following initial electrical characteristic test (II) was performed on each of the obtained single layer type photoreceptors.
And evaluated the characteristics. Initial electrical characteristic test (II) An applied voltage was applied to the surface of the photoconductor using a drum sensitivity tester manufactured by GENTEC, and the surface was charged to + 700V. Then, the surface of the photoconductor is irradiated with white light (light intensity 147 μW / cm ² ) of a halogen lamp which is an exposure light source (irradiation time 50 msec.),
The half-exposure amount E _1/2 (μJ / cm ² ) was calculated by measuring the time required for the surface potential to become 1/2, that is, + 350V. Also, 330 msec. From the start of exposure. The surface potential at the time when it passed was measured as the post-exposure potential V _L (V).

The above results are shown in Tables 2 to 4. Table 4 also shows the test results of the glass transition temperature and high temperature resistance measured in the same manner as above.

[0100]

[Table 2]

[0101]

[Table 3]

[0102]

[Table 4]

[0103] As is apparent from these tables, each of the half decay exposure Both photoreceptor of Example _{E 1/2 (μJ / cm} 2)
Is small and the post-exposure potential V _L (V) is low,
It had excellent sensitivity characteristics. Further, from Table 4, the photoreceptors of Examples have a higher extrapolation glass transition start temperature (Tig) than Comparative Examples, and no dents were observed in the high temperature resistance test, and thus the durability and heat resistance are excellent. It is understood that it is a thing. Examples 41 to 46 (Multilayer Photoreceptor for Digital Light Source) 2 parts by weight of X-type metal-free phthalocyanine as a charge generating material and 1 part by weight of polyvinyl butyral as a binder resin, together with 120 parts by weight of dichloromethane, were ball milled. Were mixed and dispersed in to prepare a coating liquid for the charge generation layer. This coating solution was applied onto an aluminum tube by a dip coating method and dried with hot air at 100 ° C. for 60 minutes to give a film thickness of 0.5 μm.
The charge generation layer of was formed.

Next, 80 parts by weight of a benzidine derivative as a hole transport material and 100 parts by weight of a polycarbonate as a binder resin were mixed and dispersed in a ball mill together with 800 parts by weight of benzene to prepare a charge transport layer. A coating solution of was prepared. Then, this coating solution is applied onto the charge generation layer by a dip coating method and dried with hot air at 90 ° C. for 60 minutes to form a charge transport layer having a film thickness of 15 μm, and a laminated photoreceptor for a digital light source is obtained. Manufactured.

Regarding each of the obtained laminated type photoreceptors,
An initial electrical characteristic test (III) was conducted to evaluate the characteristics.Initial electrical characteristics test (III) Drum sensitivity tester made by GENTEC
By applying an applied voltage to the surface of the photoconductors of both examples.
The surface was charged to -700V. And exposure
From the white light of the halogen lamp, which is the light source, to the bandpass filter
The wavelength was 780 nm (half-value width 20
nm), light intensity 16 μW / cm²The monochromatic light on the surface of the photoconductor
To the surface potential (irradiation time 80 msec.).
Measures the time required to become 1/2, that is, -350V
And half exposure E_1/2(ΜJ / cm ²) Was calculated. Well
330 msec. From the start of exposure. Surface at the time of elapsed
After exposure, the potential is V_LIt was measured as (V).

The test results are shown in Table 5.

[0107]

[Table 5]

As is clear from Table 5, all the photoreceptors of the respective examples have a small half-exposure amount E _1/2 (μJ / cm ² ) and a low post-exposure potential V _L (V). The sensitivity characteristics were excellent. Synthesis Example 11 10.6 g of 3,3'-dimethylbenzidine and 2,4-
46.4 g of dimethyl iodobenzene and 27.6 g
Of potassium carbonate and 2 g of copper powder were added to 150 ml of nitrobenzene, and the mixture was refluxed for 24 hours while blowing nitrogen gas into the reaction system with vigorous stirring. Water generated during the reaction was azeotropically distilled with nitrobenzene and taken out of the reaction system.

After cooling the reaction solution, the inorganic substances were filtered off, and the residue obtained by distilling off nitrobenzene by steam distillation was dissolved in cyclohexane and separated and purified by silica gel column chromatography. The cyclohexane was distilled off to obtain a white precipitate. It was The white precipitate was recrystallized from n-hexane to give N, represented by the formula (2-a).
N, N ', N'-tetrakis (2,4-dimethylphenyl) -3,3'-dimethylbenzidine was obtained. Yield is 1
It was 3.24 g (yield 42.1%).

The result of infrared spectroscopic analysis of the product is shown in FIG. Elemental analysis result Calculated value (%) C: 87.85 H: 7.69 N:
4.45 Measured value (%) C: 87.76 H: 7.81 N:
4.43 Melting point: 239.9 ° C Synthesis Examples 12 to 16 The compounds represented by the above formulas (2-b) and (2-f) were obtained in the same manner as in Synthesis Example 11 using appropriate starting materials. It was

The melting points of the benzidine derivatives are shown below. (Compound number) (Melting point) (2-b) 210.3 ° C (2-c) 201.4 ° C (2-d) 217.8 ° C (2-e) 210.0 ° C (2-f) 199. 2 ° C. Examples 47 to 49, Comparative Examples 32 to 37 (photoreceptor for digital) As a hole transport material (HTM),
An electrophotographic photoreceptor for digital use having a single-layer type photosensitive layer having a film thickness of 15 to 20 μm was manufactured in the same manner as in Example 1 except that the benzidine derivative represented by the compound number in Table 6 was used. The benzidine derivatives of symbols (20) to (25) used in Comparative Examples 32 to 37 are the following compounds.

[0112]

[Chemical 37]

[0113]

[Chemical 38]

[0114]

[Chemical Formula 39]

The melting points of the benzidine derivatives (20) to (25) are shown below. (Compound number) (Melting point) (20) 220.1 ° C (21) 219.7 ° C (22) 204.2 ° C (23) 195.9 ° C (24) 203.3 ° C (25) 201.0 ° C electron With respect to the photographic photoreceptor, the initial electrical characteristic test (I), the glass transition temperature and the high temperature resistance test were measured in the same manner as in Example 1. The results are shown in Table 6. In addition, for comparison, the test results of the photoconductor using the benzidine derivative represented by the symbol (13) are also shown.

[0116]

[Table 6]

Examples 50 to 58, Comparative Examples 38 to 55 (Photoreceptors for analog light sources) Tables 7 and 8 as hole transport agents
Example 11 except that the benzidine derivative described in 1. is used.
A single-layer type photoconductor for analog light source was manufactured in the same manner as in.
The obtained electrophotographic photosensitive member was subjected to the same initial electrical characteristic test (II) as in Example 11 to evaluate its characteristics. The results are shown in Tables 7 and 8. For comparison, the code (1
The test results for the photoconductor using the benzidine derivative represented by 3) are also shown.

[0118]

[Table 7]

[0119]

[Table 8]

Synthesis Example 17 16.1 g of N, N'-diacetyl-3,3 ', 5,5'-tetramethylbenzidine, 21.8 g of p-iodotoluene, 13.8 g of potassium carbonate and 1 g
Add the copper powder in 150 ml of nitrobenzene,
The mixture was refluxed for 24 hours while blowing nitrogen gas into the reaction system while vigorously stirring. Water generated during the reaction was azeotropically distilled with nitrobenzene and taken out of the reaction system.

Next, after cooling the reaction solution, the inorganic substances are filtered off,
Further, the residue obtained by distilling off nitrobenzene by steam distillation was added to 100 ml of tetrahydrofuran together with 10% hydrochloric acid and refluxed for 2 hours to deacetylate,
N, N'-di (4-methylphenyl) -3,3 ', 5
5'-Tetramethylbenzidine was obtained. Next, this N, N'-di (4-methylphenyl) -3,3 ', 5,
10.3 g of 5'-tetramethylbenzidine and 4-te
13.0 g of rt-butyl iodobenzene and 13.8
150 ml with g potassium carbonate and 1 g copper powder
Of nitrobenzene, and the mixture was refluxed for 24 hours while blowing nitrogen gas into the reaction system while stirring vigorously.
Moisture produced during the reaction was azeotroped with nitrobenzene and taken out of the reaction system as in the previous case.

After cooling the reaction solution, the inorganic substances were filtered off, and the residue obtained by distilling off nitrobenzene by steam distillation was dissolved in cyclohexane and separated and purified by silica gel column chromatography to remove the cyclohexane to obtain a white precipitate. It was Then, this white precipitate is recrystallized using n-hexane to obtain the desired product, N, N'-di (4-methylphenyl) -N, represented by the above formula (3-b).
N'-di (4-tert-butylphenyl) -3,3 ',
5,5'-Tetramethylbenzidine was obtained. Yield is 6.
The amount was 71 g (yield 39.2%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 87.67 H: 8.24 N:
4.09 measured value (%) C: 87.60 H: 8.20 N:
4.20 Melting point: 276.0 ° C. Synthesis Example 18 4-methyliodobenzene was used in place of p-iodotoluene, and 4-methyl iodobenzene was used in place of 4-tert-butyliodobenzene.
The same formula (3-e) was used as in Synthesis Example 17 except that ethyl-4′-iodobiphenyl was used in the same molar amount.
Represented by N, N'-bis (4-methylphenyl)-
N, N'-bis (4'-ethylbiphenyl-4-yl)
-3,5,3 ', 5'-Tetramethylbenzidine was obtained. The yield was 9.2 g (yield 25.0%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 89.17 H: 7.24 N:
3.59 Measured value (%) C: 89.10 H: 7.19 N:
3.61 Melting point: 181.6 ° C. Synthesis Examples 19 to 22 Using the appropriate starting materials, the formula (3
-A), (3-c), (3-d) and (3-f) benzidine derivatives were obtained.

(Compound No.) (Melting point) (3-a) 280.5 ° C. (3-c) 277.3 ° C. (3-d) 198.7 ° C. (3-f) 200.7 ° C. Examples 59 to 64, Comparative Examples 56 to 57 (Single-layer digital photoconductor) A benzidine derivative shown in Table 9 was used as the hole transport material (HTM), and the same procedure as in Example 1 was performed to obtain a film thickness of 15 to 20 μm. An electrophotographic photoreceptor for digital use having a single-layer type photosensitive layer was manufactured.

The benzidine derivatives used in the examples are shown in Table 9 by the compound number of each specific example. Further, the benzidine derivatives represented by the reference numerals (26) and (27) used in Comparative Examples 56 and 57 are the following compounds.

[0127]

[Chemical 40]

The melting points of the benzidine derivatives (26) and (27) are shown below. (Compound No.) (Melting point) (26) 224.1 ° C. (27) 301.5 ° C. About electrophotographic photoreceptors of Examples and Comparative Examples, Example 1
The initial electrical property test (I), the glass potential temperature measurement, and the high temperature resistance test were measured in the same manner as in. The results are shown in Table 9. Further, for comparison, the test results of the respective photoconductors using the benzidine derivatives represented by the symbols (13) and (18) are also shown.

[0129]

[Table 9]

Examples 65 to 82, Comparative Examples 58 to 63 (Photoreceptor for analog light source) Same as Example 11 except that the benzidine derivatives shown in Tables 10 and 11 were used as the hole transfer agent (HTM). Then, a single-layer type photoreceptor for analog light source was manufactured. The electrophotographic photoreceptors of Examples and Comparative Examples were subjected to the same initial electrical characteristic test (II) as in Example 11 to evaluate the characteristics. The results are shown in Tables 10 and 11. Further, for comparison, the test results of the respective photoconductors using the benzidine derivatives represented by the symbols (13) and (18) are also shown.

[0131]

[Table 10]

[0132]

[Table 11]

Examples 83 to 84 (Multilayer Photoreceptor for Digital Light Source) Hole Transport Material (HT
A multi-layer type photoconductor for digital light source was manufactured in the same manner as in Example 41 except that M) shown in Table 12 was used. An initial electrical characteristic test (III) was performed on each of the obtained laminated type photoreceptors in the same manner as in Example 41 to evaluate the characteristics. The test results are shown in Table 12.

[0134]

[Table 12]

Synthesis Example 23 N, N'-diacetyl-2,5,2 ', 5'-tetramethylbenzidine 16.1 g and 4-methyliodobenzene 21.8 g were reacted in the same manner as in Synthesis Example 1. Let me
N, N'-bis (4-methylphenyl) -2,5
2 ', 5'-Tetramethylbenzidine was obtained. further,
This N, N'-bis (4-methylphenyl) -2,5
12.0 g of 2 ', 5'-tetramethylbenzidine and 4
13.0 g of -tert-butyl iodobenzene was reacted in the same manner as in Synthesis Example 1 to give N represented by the formula (4-a),
N'-bis (4-methylphenyl) -N, N'-bis (4-tert-butylphenyl) -2,5,2 ', 5'-
Obtained tetramethylbenzidine. The yield was 9.0 g (yield 27.1%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 87.65 H: 8.26 N:
4.09 measured value (%) C: 87.61 H: 8.19 N:
4.19 Melting point: 180.9 ° C. Synthesis example 24 A benzidine derivative represented by the formula (4-b) was obtained by using an appropriate starting material.

Melting point: 191.5 ° C. Examples 85 and 86 (Single layer type photoreceptor for digital light source) Hole transport material (HT
A single-layer type photoreceptor for a digital light source was manufactured in the same manner as in Example 1 except that the benzidine derivative shown by the compound number in Table 13 was used as M).

Each of the single-layer type photoconductors was subjected to the above-mentioned initial electric characteristic test (I), glass potential temperature measurement and high temperature resistance test to evaluate the characteristics. The results are shown in Table 13. In addition, as comparative examples, the test results of the photoconductors using the benzidine derivatives of the symbols (13), (18) and (26) are also shown.

[0139]

[Table 13]

Examples 87 to 92 (Photoreceptor for analog light source) Single layer type photosensitive material for analog light source was prepared in the same manner as in Example 11 except that the benzidine derivative shown in Table 14 was used as the hole transport material (HTM). Manufactured body. Regarding the electrophotographic photoreceptors of Examples and Comparative Examples,
The same initial electrical characteristic test (II) as in Example 11 was conducted to evaluate the characteristic. The results are shown in Table 14. For comparison, the test results of photoconductors using the benzidine derivatives of formulas (13), (18), and (26) as hole transport materials are also shown.

[0141]

[Table 14]

Examples 93 and 94 (Multilayer Photoreceptor for Digital Light Source) Hole Transport Material (HT
A multi-layer type photoconductor for a digital light source was manufactured in the same manner as in Example 41 except that M) shown in Table 15 was used. An initial electrical characteristic test (III) was performed on each of the obtained laminated type photoreceptors in the same manner as in Example 41 to evaluate the characteristics. The test results are shown in Table 15.

[0143]

[Table 15]

Synthesis Example 25 3,3'-Dimethylbenzidine (10.6 g) and 4-ethyl-4'-iodobiphenyl (33.9 g) were mixed with 27.6 g.
150 ml with g potassium carbonate and 2 g copper powder
Of nitrobenzene, and the mixture was refluxed for 24 hours while blowing nitrogen gas into the reaction system while vigorously stirring. Water generated during the reaction was azeotropically distilled with nitrobenzene and taken out of the reaction system.

After cooling the reaction solution, the inorganic substances were filtered off, and the residue obtained by distilling nitrobenzene off by steam distillation was dissolved in cyclohexane and separated and purified by silica gel column chromatography to remove the cyclohexane to obtain a white precipitate. It was Then, the white precipitate was recrystallized from n-hexane to obtain N, represented by the formula (5-b).
N, N ', N'-tetrakis (4'-ethylbiphenyl-4-yl) -3,3'-dimethylbenzidine was obtained.
The yield was 14.7 g (yield 31.5%).

The results of infrared spectroscopic analysis of the product are shown in FIG. Elemental analysis result Calculated value (%) C: 90.07 H: 6.93 N:
3.00 Measured value (%) C: 89.98 H: 6.91 N:
3.01 Melting point: 270.4 ° C. Synthesis examples 26, 27 Using appropriate starting materials, benzidine derivatives represented by the formulas (5-a) and (5-c) were obtained.

(Compound No.) (Melting Point) (5-a) 203.3 ° C. (5-c) 281.3 ° C. Examples 95 to 97 (Single-Layer Photoreceptor for Digital Light Source) Hole Transport Material (HT
A single-layer type photoreceptor for a digital light source was manufactured in the same manner as in Example 1 except that the benzidine derivative represented by the compound number in Table 16 was used as M).

The initial electric characteristic test (I), the glass potential temperature measurement and the high temperature resistance test were conducted on the single-layer type photoreceptors of the above-mentioned respective examples to evaluate the characteristics. The results are shown in Table 16. Also, for comparison, the signs (13), (1
The test results for the photoreceptors using the benzidine derivatives of 8) and (19) are also shown.

[0149]

[Table 16]

Examples 98 to 106 (Photoreceptor for analog light source) Single layer type photosensitive material for analog light source was prepared in the same manner as in Example 11 except that the benzidine derivative shown in Table 17 was used as the hole transport material (HTM). Manufactured body. Regarding the electrophotographic photoreceptors of Examples and Comparative Examples,
The same initial electrical characteristic test (II) as in Example 11 was conducted to evaluate the characteristic. The results are shown in Table 17. For comparison, the test results of the photoconductors using the benzidine derivatives of formulas (13), (18) and (19) are also shown.

[0151]

[Table 17]

Examples 107, 108 (Multilayer Photoreceptor for Digital Light Source) Hole Transport Material (HT
A multilayer photoconductor for a digital light source was manufactured in the same manner as in Example 41, except that M) shown in Table 18 was used. An initial electrical characteristic test (III) was performed on each of the obtained laminated type photoreceptors in the same manner as in Example 41 to evaluate the characteristics. The test results are shown in Table 18.

[0153]

[Table 18]

Synthesis Example 28 N, N'-diacetyl-3,3'-dimethylbenzidine (14.9 g) and paraiodobenzene (21.8 g) were reacted in the same manner as in Synthesis Example 1 to give N, N'-dip. -Trill-
3,3'-Dimethylbenzidine was obtained. Further, 12.0 g of this N, N'-di-p-tolyl-3,3'-dimethylbenzidine and 15.4 g of 4-ethyl-4'-iodobiphenyl were reacted in the same manner as in Synthesis Example 1, N,
N'-di-p-tolyl-N, N'-di (4'-ethylbiphenyl-4-yl) -3,3'-dimethylbenzidine (hereinafter referred to as 6-c) was obtained. The yield was 8.82 g (yield 23.7%).

The results of infrared spectroscopic analysis of the above compound 6-c are shown in FIG.
Shown in 11. Elemental analysis result Calculated value (%) C: 89.32 H: 6.96 N:
3.72 actual value (%) C: 88.99 H: 6.90 N:
3.90 Melting point: 135.6 ° C. Synthesis example 29 N, N′-di-p was prepared in the same manner as in Synthesis example 28 except that 4-iodobiphenyl was used instead of 4-ethyl-4′-iodobiphenyl. -Tolyl-N, N'-di (biphenyl-4-yl) -3,3'-dimethylbenzidine (hereinafter referred to as 6-a) was obtained.

Melting point: 181.5 ° C. Synthesis Example 30 N, N was prepared in the same manner as in Synthesis Example 28 except that 4-methyl-4′-iodobiphenyl was used instead of 4-ethyl-4′-iodobiphenyl. ′ -Di-p-tolyl-N,
N'-di (4-methylbiphenyl-4'-yl) -3,
3'-Dimethylbenzidine (hereinafter referred to as 6-b) was obtained.

Melting point: 168.3 ° C. Examples 109 to 111 (single layer type photoconductor for digital light source) Hole transport material (HT
A single-layer type photoreceptor for a digital light source was manufactured in the same manner as in Example 1 except that the benzidine derivative shown in Table 19 was used as M). Each of the obtained photoconductors was subjected to the above-mentioned initial electrical characteristic test (I) to evaluate the characteristics. The results are shown in Table 19. For comparison, equations (13) and (18)
The test results for the photoconductor using the benzidine derivative are also shown.

[0158]

[Table 19]

Examples 112 to 120 (Single layer type photoreceptor for analog light source) Hole transporting agent (HTM)
A single-layer type photoreceptor for analog light source was manufactured in the same manner as in Example 11 except that the benzidine derivative shown in Table 20 was used. The electrophotographic photoreceptors of Examples and Comparative Examples were subjected to the same initial electrical characteristic test (II) as in Example 11 to evaluate the characteristics. The results are shown in Table 20. In addition, for comparison, the test results of the photoconductors using the benzidine derivatives of the symbols (13) and (18) are also shown.

[0160]

[Table 20]

[0161]

INDUSTRIAL APPLICABILITY The benzidine derivative of the present invention has excellent compatibility with a binder resin while maintaining a high hole transporting ability, and has a higher melting point than conventional benzidine derivatives. When dispersed in the film, the glass transition temperature of the film can be made higher than before, and the durability and heat resistance of the film can be improved. Therefore, the benzidine derivative of the present invention can be suitably used as a hole transport material in, for example, a solar cell, an electroluminescence element, an electrophotographic photoreceptor and the like.

The electrophotographic photosensitive member of the present invention has high sensitivity and excellent durability and heat resistance.

[Brief description of drawings]

FIG. 1 is a graph showing an infrared spectroscopic analysis result of a benzidine derivative of Synthesis Example 1.

FIG. 2 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 2.

FIG. 3 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 4.

FIG. 4 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 7.

FIG. 5 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 8.

6 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 11. FIG.

7 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 17. FIG.

FIG. 8 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 18.

FIG. 9 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 23.

FIG. 10 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 25.

11 is a graph showing the results of infrared spectroscopic analysis of the benzidine derivative of Synthesis Example 28. FIG.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03G 5/06 312 H01L 51/00 31/04 // C09K 11/06 Z 9280-4H (31) Priority claim number Japanese Patent Application No. 5-257209 (32) Priority date 5 (1993) October 14 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-304437 (32) ) Priority Day 5 (1993) December 3 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 5-304438 (32) Priority Day 5 (1993) December 3 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 6-70422 (32) Priority date Hei 6 (1994) April 8 (33) Priority claiming country Japan (JP) ( 31) Priority claim number Japanese Patent Application No. 6-70423 (32) Priority date Hei 6 (1994) April 8 (33) Country of priority claim Japan (JP) (31) Priority right holder Number Japanese Patent Application No. 6-70424 (32) Priority Date April 6 (1994) April 8 (33) Priority Claim Country Japan (JP) (31) Priority Claim Number Japanese Patent Application No. 6-70425 (32) Priority Date Hei 6 (1994) April 8 (33) Priority claiming country Japan (JP) (31) Priority claim number Japanese Patent Application No. 6-70426 (32) Priority Day Hei 6 (1994) April 8 (33) Priority claiming country Japan (JP) (31) Priority claiming number Japanese Patent Application No. 6-70427 (32) Priority date Hei 6 (1994) April 8 (33) Priority claiming country Japan (JP) (72) Invention Toshiyuki Fukami 1-22-28 Tamazo, Chuo-ku, Osaka-shi, Osaka Prefecture Mita Kogyo Co., Ltd. (72) Inventor Hideo Nakamori 1-2-2 Tatamazo, Chuo-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd. (72) Invention Mikio Tsunoi 1-22-28 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Prefecture Mita Kogyo Co., Ltd. (72) Inventor Sakae Saito 1-2-28 Tamatsukuri, Chuo-ku, Osaka City, Osaka (72) Inventor Hiroshi Shiomi 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Mita Kogyo Co., Ltd. (72) Inventor Keisuke Sumita 1-228 Tamatsukuri, Chuo-ku, Osaka-shi Mita Kogyo Co., Ltd. (72) Maki Uchida 1-2-2 Tamatsukuri, Chuo-ku, Osaka-shi, Osaka Within Mita Industry Co., Ltd.

Claims (15)

[Claims] 1. General formula (1):(In the formula, R¹, R²Are the same or different
Represents an alkyl group, R ³And R^FourAre the same or different
Represents an alkyl group, an alkoxy group or a halogen atom.
And R^FiveAnd R⁶Are the same or different and have 3 to 5 carbon atoms
Aryl which may have an alkyl group or a substituent
Indicates a group. m and n are the same or different and are 2 or 3
Indicates. ) The benzidine derivative represented by. 2. The general formula (1 ′): The benzidine derivative according to claim 1, wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , m and n are the same as those in claim 1. 3. General formula (2): (In the formula, R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ ,
R ¹⁴ , R ¹⁵ and R ¹⁶ are the same or different and each represents an alkyl group, an alkoxy group or a halogen atom. ) The benzidine derivative represented by. 4. General formula (3): (In the formula, R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are the same or different and represent an alkyl group or an alkoxy group, and R ²¹ and R ²² are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. shows, benzidine derivative represented by the.) of an aryl group which may R ²³ and R ²⁴ have the same or different and each represents a hydrogen atom, an alkyl group or a substituted group. 5. The general formula (3 ′): (Wherein R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ are the same as in claim 4, R ²⁵ and R ²⁶ are the same or different and represent a hydrogen atom or an alkyl group, and R ²⁷ and R ²⁸ are the same or different. A benzidine derivative according to claim 4, which is represented by an alkyl group having 3 to 5 carbon atoms or an aryl group which may have a substituent). 6. General formula (4): embedded image (In the formula, R ²⁹ , R ³⁰ , R ³¹ and R ³² are the same or different and represent an alkyl group or an alkoxy group, and R ³³ and R ³⁴ are the same or different and represent an alkyl group, an alkoxy group or a halogen atom; ³⁵ and R ³⁶ are the same or different and each represents an alkyl group having 3 to 5 carbon atoms.). 7. General formula (5): embedded image (In the formula, R ³⁷ , R ³⁸ , R ³⁹ and R ⁴⁰ are the same or different and each represents a hydrogen atom or an alkyl group, and R ⁴¹ and R ⁴²
Are the same or different and each represents an alkyl group. ) The benzidine derivative represented by. 8. The general formula according to claim 1 on a conductive substrate.
An electrophotographic photoreceptor comprising a photosensitive layer containing a benzidine derivative represented by (1). 9. The electrophotographic photosensitive member according to claim 8, wherein the benzidine derivative is represented by the general formula (1 ′) according to claim 2. 10. The general formula according to claim 3 on a conductive substrate.
An electrophotographic photoreceptor comprising a photosensitive layer containing a benzidine derivative represented by (2). 11. The general formula according to claim 4 on a conductive substrate.
An electrophotographic photoreceptor comprising a photosensitive layer containing a benzidine derivative represented by (3). 12. The electrophotographic photosensitive member according to claim 11, wherein the benzidine derivative is represented by the general formula (3 ′) according to claim 5. 13. The general formula of claim 6 on a conductive substrate.
An electrophotographic photoreceptor comprising a photosensitive layer containing a benzidine derivative represented by (4). 14. The general formula of claim 7 on a conductive substrate.
An electrophotographic photoreceptor comprising a photosensitive layer containing a benzidine derivative represented by (5). 15. An electrophotographic photosensitive member comprising a conductive substrate on which a single photosensitive layer is provided, wherein the single photosensitive layer comprises a benzidine derivative represented by the following general formula (6) together with a charge generating material. A positively charged electrophotographic photosensitive member characterized by containing. [Chemical 8] (In the formula, R ⁴³ , R ⁴⁴ , R ⁴⁵ , R ⁴⁶ , R ⁴⁷ and R ⁴⁸ are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.)