JP5193456B2 - Bistriphenylamine derivatives and electrophotographic photoreceptors - Google Patents

Description

  The present invention relates to a novel bistriphenylamine derivative useful as a charge transfer agent used in an electrophotographic photoreceptor and an electrophotographic photoreceptor using the same.

  In an image forming apparatus such as a copying machine, a laser printer, or a facsimile, an organic photoreceptor having sensitivity suitable for a wavelength region of a light source used in the apparatus is used. This organic photoconductor is easier to manufacture than conventional inorganic photoconductors and has a high degree of design freedom because there are various options for the constituent materials of the photoconductor such as a charge transport agent, a charge generator, and a binder resin. It is widely used because of its advantages.

  The organic photoreceptor includes a single-layer photoreceptor in which a charge generator is dispersed in a photosensitive layer containing a charge transport agent, a charge generation layer containing a charge generator, and a charge transport layer containing a charge transport agent. And a stacked type photoreceptor in which the two are separated and stacked. In any of the above photoreceptors, in order to improve the sensitivity characteristic, it is required to use a charge transport agent having a high charge transport property.

Therefore, various charge transport agents have been proposed conventionally. For example, a butadienylbenzeneamine derivative represented by the following formula HT-A (see Patent Document 1) or a styryl compound (see Patent Document 2) represented by the following formula HT-B is used as the charge transport agent. The electrophotographic photosensitive member using these is proposed.

JP 2005-289877 A Japanese Patent No. 312348

However, although the butadienylbenzeneamine derivative is excellent in charge transporting property, it has low compatibility with the binder resin used for forming the photosensitive layer, and thus it is difficult to uniformly disperse in the photosensitive layer. There was a drawback that charge transfer was difficult to occur. Further, since the butadienylbenzeneamine derivative has low solubility in an organic solvent, it has a problem that it is easily crystallized when forming a photosensitive layer.
Further, although the above styryl compound is also excellent in charge transporting property, it is difficult to uniformly disperse in the photosensitive layer because of low compatibility with the binder resin used for forming the photosensitive layer, resulting in charge transfer. There was a drawback that it was difficult to occur. Furthermore, conventional photoreceptors prepared using the styryl compound as a charge transport agent generally have low solvent resistance, and may be gradually dissolved in an organic solvent when subjected to liquid development (wet development). There was also a problem that it could not stand the use of.
As described above, the conventional butadienylbenzeneamine derivatives and styryl compounds themselves have high charge mobility. However, when this is used for a photoreceptor as a charge transport agent, the characteristics thereof are high. Under the present circumstances, the residual potential of the photoconductor becomes high during long-term use, and sufficient photosensitivity cannot be obtained.

  Therefore, the present invention provides a novel compound having excellent charge transportability and capable of achieving high sensitivity when used as a charge transport agent for a photoreceptor, and using this as a charge transport agent. An object of the present invention is to provide an electrophotographic photoreceptor excellent in sensitivity characteristics.

  As a result of intensive studies to solve the above problems, the present inventors have found that a novel bistriphenylamine derivative having a specific structure represented by the following general formula (1) has an excellent charge transport property. In addition, it is possible to achieve high sensitivity when used as a charge transfer agent for a photoreceptor, and the bistriphenylamine derivative has a high molecular weight, so that it has excellent solvent resistance and is suitable for a liquid development photoreceptor. As a result, the present invention has been completed.

（式中、Ｒ₁、Ｒ₂は各々独立して、水素原子、アリール基、アルキル基またはアルコキシ基（ここで、アリール基、アルキル基およびアルコキシ基はそれぞれ置換基を有していてもよい）を示し、Ａｒ₁、Ａｒ₂は各々独立して、アリール基、複素環式基または縮合複素環式基（ここで、アリール基、複素環式基または縮合複素環式基はそれぞれ置換基を有していてもよい）を示し、Ａはアルキレン基または酸素原子を示す。ｎ、ｍは１である。）
（２）少なくとも電荷発生剤および電荷輸送剤を含有する感光層を備えた電子写真感光体であって、前記電荷輸送剤は前記（１）に記載のビストリフェニルアミン誘導体からなる、ことを特徴とする電子写真感光体。
That is, the present invention has the following configuration.
(1) A bistriphenylamine derivative represented by the following general formula (1).

(Wherein R ₁ and R ₂ are each independently a hydrogen atom, aryl group, alkyl group or alkoxy group (wherein the aryl group, alkyl group and alkoxy group each may have a substituent)) Ar ₁ and Ar ₂ are each independently an aryl group, a heterocyclic group or a condensed heterocyclic group (wherein the aryl group, heterocyclic group or condensed heterocyclic group has a substituent, And A represents an alkylene group or an oxygen atom, and n and m are 1. )
(2) An electrophotographic photosensitive member provided with a photosensitive layer containing at least a charge generating agent and a charge transporting agent, wherein the charge transporting agent comprises the bistriphenylamine derivative described in (1) above. An electrophotographic photoreceptor.

  According to the present invention, there is provided a novel compound having excellent charge transportability and capable of achieving high sensitivity when used as a charge transport agent for a photoreceptor, and using this as a charge transport agent. An electrophotographic photoreceptor excellent in sensitivity characteristics can be provided. Furthermore, the electrophotographic photoreceptor of the present invention is excellent in solvent resistance and can be suitably used as a liquid developing photoreceptor.

Hereinafter, the present invention will be described in detail.
(Bistriphenylamine derivative)
The bistriphenylamine derivative of the present invention is a novel compound represented by the above general formula (1), and is useful as a charge transport agent as described later.

In the general formula (1), R ₁ and R ₂ are each independently selected and represent a hydrogen atom, an aryl group, an alkyl group or an alkoxy group. Specifically, examples of the aryl group include aryl groups having 6 to 14 carbon atoms such as a phenyl group, a naphthyl group, a tolyl group, a xylyl group, an anthryl group, and a phenanthryl group. Examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, pentyl group, isopentyl group, neopentyl group, and hexyl group. And a straight or branched alkyl group having 1 to 8 carbon atoms, such as an octyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an s-butoxy group, a t-butoxy group, a pentyloxy group, an isopentyloxy group, and a neopentyloxy group. And a straight or branched alkoxy group having 1 to 6 carbon atoms such as a hexyloxy group.
These aryl groups, alkyl groups and alkoxy groups may each have one or more kinds of substituents, and when they have two or more kinds of substituents, they may be the same. , May be different. For example, examples of the substituent for substituting an alkyl group or an alkoxy group include an alkoxy group having 1 to 6 carbon atoms and an aryl group. Examples of the substituent for substituting an aryl group include an alkyl group having 1 to 6 carbon atoms, An alkoxy group, an aryl group, etc. are mentioned.

In the general formula (1), Ar ₁ and Ar ₂ are each independently selected and represent an aryl group, a heterocyclic group, or a condensed heterocyclic group. Specifically, examples of the aryl group include condensed aromatic rings such as a phenyl group, a naphthyl group, and an anthryl group. Examples of the heterocyclic group include monovalent groups such as imidazole, pyrazole, pyridazine, pyrimidine, triazole, thiophene, dithiol, thiazole, and thiadiazole. Examples of the condensed heterocyclic group include monovalent groups of carbazole, benzothiazole, benzoazole, quinoline, quinoxaline, and benzothiazine.
These aryl groups, heterocyclic groups and condensed heterocyclic groups may each have one or more kinds of substituents, and when they have two or more kinds of substituents, they are the same. May be different or different. For example, the substituent for substituting an aryl group, a heterocyclic group or a condensed heterocyclic group includes an alkyl group, an alkoxy group, a halogen group, a carboxy group, an ester group, an acyl group, an amino group, an alkylamino group, and a nitro group. , A mercapto group, an aryl group, and the like.

Specific examples of Ar ₁ and Ar ₂ in the general formula (1) include tolyl groups such as 2-methylphenyl, 3-methylphenyl and 4-methylphenyl; 2,4-dimethylphenyl and 2,6-dimethylphenyl. Xylyl groups such as 3,4-dimethylphenyl and 3,5-dimethylphenyl; 2-ethylphenyl, 4-ethylphenyl, 2-n-propylphenyl, 4-n-propylphenyl, 3-iso-propylphenyl, 4-iso-propylphenyl, 2,6-diethylphenyl, 2-n-butylphenyl, 4-n-butylphenyl, 4-sec-butylphenyl, 4-tert-butylphenyl, 4-hexylphenyl, 2,6 Other alkylphenyl groups such as diisopropylphenyl; aminophenyl groups such as 4-aminophenyl; Alkoxyphenyl groups such as siphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, 4-ethoxyphenyl; condensed aromatic ring groups such as naphthyl and phenanthryl; heterocyclic groups such as imidazolyl and pyrazoyl; carbazolyl, And condensed heterocyclic groups such as benzothiazolyl and quinolyl;

  In the general formula (1), A represents an alkylene group or an oxygen atom. Here, as an alkylene group, C1-C3 hydrocarbon groups, such as a methylene group, ethylene group, a propylene group, are mentioned, for example.

In the general formula (1), n and m are 1 . Na us, the general formula (1) are the same for R ₁ and R ₂ or Ar ₁ and Ar _2, and if you are denoted with different reference numerals (i.e., R ₁ in the formula (1) and R ₂ Or, Ar ₁ and Ar ₂ in the general formula (1) may be the same as or different from each other, but they are represented by the same reference numerals (that is, the general formula In (1), two R _{1 s} , R _{2 s} , Ar _{1 s} , Ar _{2 s} each present in the same number are the same.

  As described above, in the bistriphenylamine derivative of the present invention represented by the general formula (1), the amino group is symmetric with respect to the alkylene group or oxygen atom represented by A through the benzene ring bonded thereto. Is a compound having a structure existing in With such a structure, the molecule can be polar, so that the solubility and compatibility are improved, and as a result, an excellent charge transport agent capable of obtaining a highly sensitive photoreceptor. Can be used as

Examples of the compound represented by the general formula (1) according to the present invention include HT- 6 to HT-8 shown below. However, the bistriphenylamine derivative according to the present invention is not limited to these.

をＷｉｔｔｉｇ反応によって合成する。このとき、一般式（２）で示される末端部と一般式（３）で示される末端部とが同じ種類（すなわち、４つの末端部が全て同じ種類）であってもよいし、一般式（２）で示される末端部と一般式（３）で示される末端部とは異なる種類であってもよい。４つの末端部の全てが同種の場合、ＨＴ−１、ＨＴ−２、ＨＴ−６、ＨＴ−７、ＨＴ−８のような構造の化合物が得られる。一方、一般式（２）で示される末端部と一般式（３）で示される末端部とが異なる場合（すなわち、２種類の末端部を含む場合）、ＨＴ−３、ＨＴ−４、ＨＴ−５のような構造の化合物が得られる。具体的には、後述する実施例における化合物２−１〜２−３のように、上記に示した末端部にＣｌ等のハロゲン基が付いた化合物を合成すればよい。
Bi string phenylamine derivative can be synthesized by known production methods. For example, bi string phenylamine derivatives such as the HT-1~HT-8 utilizes Wittig reaction and the coupling reaction can be obtained by the method described in the examples below.
Specifically, first, four terminal portions bonded to the nitrogen atom (that is, the portions represented by the following general formulas (2) and (3) in the general formula (1))

Is synthesized by the Wittig reaction. At this time, the terminal part shown by General formula (2) and the terminal part shown by General formula (3) may be the same kind (namely, all four terminal parts are the same kind), or General formula ( The terminal part represented by 2) and the terminal part represented by the general formula (3) may be of different types. When all four terminal portions are the same, a compound having a structure such as HT-1, HT-2, HT-6, HT-7, or HT-8 is obtained. On the other hand, when the terminal part represented by the general formula (2) and the terminal part represented by the general formula (3) are different (that is, when two kinds of terminal parts are included), HT-3, HT-4, HT- 5 is obtained. Specifically, a compound having a halogen group such as Cl at the terminal portion as shown above may be synthesized, such as compounds 2-1 to 2-3 in Examples described later.

Next, a terminal portion synthesized by the Wittig reaction is subjected to a coupling reaction with a bisphenylamine compound having two amino groups such as compounds 3-1 to 3-4 in Examples described later. At this time, when coupling different types of terminal portions, the coupling reaction is performed in multiple stages as in the methods of Comparative Examples 1-3, 1-4, and 1-5 described later. That's fine.
The reaction conditions (reaction temperature, reaction time, etc.) in the Wittig reaction and coupling reaction are not particularly limited, and may be set as appropriate.

(Electrophotographic photoreceptor)
The electrophotographic photosensitive member of the present invention is provided with a photosensitive layer containing at least a charge generating agent and a charge transporting agent, and uses the above-described bistriphenylamine derivative of the present invention as the charge transporting agent. .
Specifically, the structure of the photosensitive layer in the electrophotographic photosensitive member of the present invention includes a so-called single-layer type photosensitive member in which a charge generating agent and a charge transporting agent are mixed in the same layer, and a charge generating agent. Each photosensitive layer is composed of a component such as a charge generating agent and a charge transporting agent together with a binder resin, etc., although the layer and the layer containing the charge transporting agent are separated. It is formed by dissolving and dispersing in a dispersion medium (solvent) and applying and drying the obtained coating solution on a conductive substrate.

  The charge generating agent used in the electrophotographic photoreceptor of the present invention is not particularly limited. For example, metal-free phthalocyanine, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, α-titanyl phthalocyanine, Y-type titanyl phthalocyanine, V-type hydroxygallium Phthalocyanine pigments such as phthalocyanine; perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, pyrylium pigments, Organic photoconductors such as ansanthrone pigment, triphenylmethane pigment, selenium pigment, toluidine pigment, pyrazoline pigment, quinacridone pigment; selenium, selenium-tellurium, selenium-hi , Cadmium sulfide, inorganic photoconductive materials such as amorphous silicon; and the like. Among these, in particular, at least one selected from phthalocyanine-based pigments, particularly metal-free phthalocyanine (for example, X-type metal-free phthalocyanine), titanyl phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine is red or 650 nm or more such as LED or laser. It is preferable in view of the electrical characteristics of the photoreceptor when infrared light is used as the exposure light source. In addition, a charge generating agent may be used independently and may use 2 or more types together.

In the electrophotographic photoreceptor of the present invention, the above-described bistriphenylamine derivative used as a charge transport agent functions as a hole transport agent.
In the electrophotographic photoreceptor of the present invention, other conventionally known hole transporting agents may be contained in the photosensitive layer in combination with the bistriphenylamine derivative. Examples of such other hole transporting agents include bisstilbenediamine derivatives, bistriphenylamine derivatives, triphenylaminostyryl derivatives, stilbeneamine-hydrazone derivatives, and the like.

  In the electrophotographic photoreceptor of the present invention, an electron transport agent can also be contained as a charge transport agent. Examples of the electron transport agent include diphenoquinone derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, thioxanthone derivatives (2,4,8-trinitrothioxanthone, etc.), fluorenone derivatives (3,4,5,5). 7-tetranitro-9-fluorenone derivatives, etc.), anthracene derivatives, acridine derivatives, dinitrobenzene, dinitroanthracene, dinitroacridine, succinic anhydride derivatives, maleic anhydride derivatives, dibromomaleic anhydride derivatives, etc. Is mentioned.

  In the electrophotographic photoreceptor of the present invention, various conventionally known binder resins can be employed as the binder resin used for forming the photosensitive layer. Examples of the binder resin include polycarbonate, polyester, polyarylate, polystyrene, polymethacrylic acid ester, and the like. These resins are preferable from the viewpoint of further improving the compatibility with the bistriphenylamine derivative of the present invention and the properties such as the strength and abrasion resistance of the photosensitive layer. Moreover, these binder resins are excellent in compatibility with the charge generating agent and the charge transport agent, and do not have a site in the molecule that interferes with the charge transport property of the charge transport agent. Therefore, by using such a binder resin, an electrophotographic photosensitive member with higher sensitivity can be obtained.

  In the electrophotographic photoreceptor of the present invention, as the dispersion medium used for forming the photosensitive layer, various organic solvents conventionally used in photosensitive layer forming coating solutions can be employed. Specifically, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; dichloromethane and dichloroethane Halogenated hydrocarbons such as chloroform, carbon tetrachloride and chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, dioxane, dioxolane, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone and cyclohexanone; ethyl acetate, Examples include esters such as methyl acetate; dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, and the like. Among these, in particular, at least one organic solvent selected from the group consisting of tetrahydrofuran, dioxane, dioxolane, cyclohexanone, toluene, xylene, dichloromethane, dichloroethane, and chlorobenzene is a component such as a charge generator, a charge transport agent, and a binder resin. Is preferable for stable dispersion.

  In the electrophotographic photosensitive member of the present invention, the coating solution used for forming the photosensitive layer (that is, a mixed solution composed of the above components, binder resin, dispersion medium, etc.) does not adversely affect the electrophotographic characteristics. In addition to the above components, various conventionally known additives (for example, antioxidants, radical scavengers, singlet quenchers, deterioration inhibitors such as UV absorbers, softeners, plasticizers, surface modification) Agents, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, etc.). In order to improve the sensitivity of the photosensitive layer to be formed, for example, a known sensitizer such as terphenyl, halonaphthoquinones, acenaphthylene, or the like may be used in combination with the charge generator. Further, for the purpose of improving the dispersibility of the charge transporting agent or the charge generating agent and the smoothness of the photosensitive layer surface, a surfactant, a leveling agent or the like may be added.

  There is no restriction | limiting in particular as an electroconductive base | substrate in the electrophotographic photoreceptor of this invention, Various materials which have electroconductivity are employable. For example, simple metals such as iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass, and plastic materials on which these metals are deposited or laminated, Further examples include glass coated with aluminum iodide, tin oxide, indium oxide, and the like. Furthermore, the conductive substrate used in the present invention may have a surface subjected to an oxide film treatment or a resin film treatment. The conductive substrate is used in the form of a drum, a sheet, or the like depending on the structure of the image forming apparatus to be applied. The conductive substrate preferably has sufficient mechanical strength.

Hereinafter, the production method of the electrophotographic photoreceptor of the present invention will be described for each constitution of the photosensitive layer.
(Manufacture of single layer type electrophotographic photoreceptor)
The single-layer type electrophotographic photoreceptor comprises a charge generator, a bistriphenylamine derivative (hole transport agent) of the present invention, a binder resin, and an electron transport agent and various additives as necessary. It is obtained by dispersing or dissolving in a suitable dispersion medium, coating the resulting photosensitive layer forming coating solution on a conductive substrate, and drying to form a photosensitive layer. For the preparation (mixing and dispersion) of the coating solution, known means such as a roll mill, a ball mill, an attritor, a paint shaker, and an ultrasonic disperser may be used.

In the coating solution for producing a single layer type photoreceptor, the charge generating agent is blended in an amount of 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the binder resin. Good. What is necessary is just to mix | blend a hole transport agent in the ratio of 5-200 weight part with respect to 100 weight part of binder resin, Preferably it is 50-150 weight part. What is necessary is just to mix | blend an electron transport agent in the ratio of 5-200 weight part with respect to 100 weight part of binder resin, Preferably it is 10-100 weight part. In the case where the electron transport agent and the hole transport agent are used in combination, the total amount of the electron transport agent and the hole transport agent is 20 to 500 parts by weight, preferably 30 to 200 parts by weight with respect to 100 parts by weight of the binder resin. It is appropriate to do.
What is necessary is just to set the thickness of the photosensitive layer in a single layer type photoreceptor so that it may become 5-100 micrometers, for example, Preferably it is 10-50 micrometers.

(Manufacture of multilayer electrophotographic photoreceptors)
The laminated electrophotographic photosensitive member comprises a charge generator and the bistriphenylamine derivative (hole transport agent) of the present invention, together with an appropriate binder resin and dispersion medium (if necessary, an electron transport agent and the above-mentioned (Including various additives) to prepare a dispersion, and this dispersion is applied onto a conductive substrate by a known means and dried to obtain a charge generation layer and a charge transport layer (positive layer). And a hole transport layer). For the preparation of the dispersion, known means such as a roll mill, a ball mill, an attritor, a paint shaker, and an ultrasonic disperser may be used.

In the dispersion liquid for forming the charge generation layer in the single layer type photoreceptor, the charge generation agent is blended in an amount of 5 to 1000 parts by weight, preferably 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin. That's fine. On the other hand, in the dispersion liquid for forming the charge transport layer, the hole transport agent may be blended in an amount of 10 to 100 parts by weight, preferably 30 to 80 parts by weight, based on 100 parts by weight of the binder resin. Moreover, when using together a positive hole transport agent and an electron transport agent, the total amount should just mix | blend in the ratio of 10-500 weight part with respect to 100 weight part of binder resin, Preferably it is 30-200 weight part.
The thickness of each layer in the multilayer photoreceptor is 0.01 to 5 μm, preferably 0.1 to 3 μm for the charge generation layer, and 2 to 100 μm, preferably 5 to 50 μm for the charge transport layer.

  Between the single-layer or multilayer photosensitive layer and the conductive substrate, or between the charge generation layer and the charge transport layer constituting the multilayer photosensitive layer, an intermediate layer as long as the characteristics of the photoreceptor are not impaired. Or a barrier layer may be formed. A protective layer may be formed on the surface of the photosensitive layer.

  The electrophotographic photoreceptor of the present invention is preferably used for so-called liquid development. For example, in a conventionally known image forming apparatus for wet development, a photosensitive member is charged by a charger, and a print pattern is exposed by an exposure light source. Then, development by a wet developing device, that is, a toner image of a printing pattern is formed, the toner image is transferred to a transfer material (paper, etc.) by a transfer device, the toner is scraped off by a cleaning blade, and then the static electricity is removed by a static elimination light source. Do.

Hereinafter, the bistriphenylamine derivative and the electrophotographic photosensitive member of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited only to the following Examples.
[Synthesis of bistriphenylamine derivatives]
( Comparative Example 1-1)
(I) Synthesis of Compound 1-0 First, according to the following reaction formula (I), compound 1-0 represented by formula (I) was synthesized. That is, 20 g (0.124 mol) of 4-chlorobenzyl chloride and 30 g (0.181 mol) of triethyl phosphite were added to a 200 mL flask, and the mixture was heated and stirred at 180 ° C. for 8 hours. Then, after cooling to room temperature, excess phosphorous acid triethyl ester was distilled off under reduced pressure to obtain 29.3 g of Compound 1-0 as a white liquid (yield 90%).

(Ii) Synthesis of Compound 2-1 Next, according to the following reaction formula (II), a compound 2-1 represented by the formula (II) was synthesized. That is, 13 g (0.049 mol) of the compound 1-0 obtained above was added to a 500 mL two-necked flask, and then substituted with argon gas and dried with 100 mL of tetrahydrofuran (THF) and 28% sodium methoxide. 15.2 g (0.079 mol) of kidney was added and stirred at 0 ° C. for 30 minutes. Next, 6 g (0.057 mol) of benzaldehyde (compound 1-1 in the formula (II)) was dissolved in 300 mL of dry THF, and the mixture was stirred at room temperature for 12 hours. Thereafter, the reaction solution was poured into ion exchanged water and extracted with toluene, and the organic layer was washed 5 times with ion exchanged water. Next, the organic layer was dried over anhydrous sodium sulfate, and the solvent was distilled off. Thereafter, the residue was purified with a toluene / methanol mixed solvent (toluene / methanol = 20 mL / 100 mL) to obtain 8.9 g of compound 2-1 as a white crystal (yield 85%).

(Iii) Synthesis of bistriphenylamine derivative (HT-1) Finally, HT-1 represented by the formula (III) was synthesized according to the following reaction formula (III). That is, 5.9 g (0.03 mol) of 1-amino-3-[(4-aminophenyl) methyl] benzene (a compound represented by 3-1 in the formula (III)) in a 2 L two-necked flask. ), (2-biphenyl) dicyclohexylphosphine 0.21 g (0.0006 mol), tris (dibenzylideneacetone) dipalladium 0.28 g (0.0.0003 mol), and t-butoxy sodium 14.4 g (.0. 15 mol), 25.8 g (0.12 mol) of the compound 2-1 obtained above, and 500 mL of purified o-xylene were added, followed by replacement with argon gas and stirring at 120 ° C. for 5 hours. Then, after cooling to room temperature, the organic layer was washed 3 times with ion exchange water. Next, the organic layer was dried over anhydrous sodium sulfate, further adsorbed with activated clay, and xylene was distilled off under reduced pressure. Thereafter, the residue was purified by column chromatography (developing solvent: chloroform / hexane) to obtain 19.7 g of compound (HT-1) as a solid (yield 72%).

  An infrared absorption spectrum chart of the obtained compound (HT-1) is shown in FIG.

( Comparative Example 1-2)
In place of the 1-amino-3-[(4-aminophenyl) methyl] benzene (compound 3-1) used in the synthesis of (iii) HT-1 in Comparative Example 1-1, 1-amino shown below Compound (HT-2) shown below as a solid is the same as Comparative Example 1-1 except that 6 g (0.03 mol) of -3- (4-aminophenoxy) benzene (Compound 3-4) is used. Was obtained (yield 70%).

( Comparative Example 1-3)
(Ii) Synthesis of Compound 2-2 and Compound 2-3 According to the following reaction formula (IIa), compound 2-2 represented by the formula (IIa) was synthesized. That is, instead of benzaldehyde (Compound 1-1) used in the synthesis of (ii) Compound 2-1 of Comparative Example 1-1, 6.84 g of 4-methylbenzaldehyde (Compound 1-2 in Formula (IIa)) Except having used (0.057 mol), it carried out similarly to the comparative example 1-1, and obtained 9.5g of compounds 2-2 (yield 85%).

On the other hand, the compound 2-3 represented by the formula (IIb) was synthesized according to the following reaction formula (IIb). That is, instead of benzaldehyde (Compound 1-1) used in the synthesis of (ii) Compound 2-1 of Comparative Example 1-1, 7.52 g (0 of cinnamaldehyde (Compound 1-3 in Formula (IIb)) 0.057 mol) was carried out in the same manner as in Comparative Example 1-1 to obtain 9.8 g of Compound 2-3 (yield 83%).

(Iii) Synthesis of bistriphenylamine derivative (HT-3) According to the following reaction formula (IIIa), first, compound 4-1 represented by the formula (IIIa) is synthesized, and then represented by the formula (IIIa). HT-3 was synthesized.

  That is, 5.9 g (0.03 mol) of the 1-amino-3-[(4-aminophenyl) methyl] benzene (Compound 3-1) and (2-biphenyl) dicyclohexyl were placed in a 2 L two-necked flask. 0.11 g (0.0003 mol) of phosphine, 0.14 g (0.00015 mol) of tris (dibenzylideneacetone) dipalladium, 7.2 g (0.075 mol) of t-butoxy sodium, compound 2- After 13.7 g (0.06 mol) of 2 and 500 mL of purified o-xylene were added, argon gas replacement was performed and the mixture was stirred at 120 ° C. for 5 hours. Then, after cooling to room temperature, the organic layer was washed 3 times with ion exchange water. Next, the organic layer was dried over anhydrous sodium sulfate, further adsorbed with activated clay, and xylene was distilled off under reduced pressure. Thereafter, the residue was purified by column chromatography (developing solvent: chloroform / hexane) to obtain 13.1 g of Compound 4-1 (yield 75%).

Next, in a 2 L two-necked flask, 17.5 g (0.03 mol) of the compound 4-1 obtained above, 0.11 g (0.0003 mol) of (2-biphenyl) dicyclohexylphosphine, Benzylideneacetone) dipalladium (0.14 g, 0.00015 mol), t-butoxy sodium (7.2 g, 0.075 mol), compound 2-3 obtained above (14.4 g, 0.06 mol), and purification o -After adding 500 mL of xylene, argon gas substitution was performed and it stirred at 120 degreeC for 5 hours. Then, after cooling to room temperature, the organic layer was washed 3 times with ion exchange water. Next, the organic layer was dried over anhydrous sodium sulfate, further adsorbed with activated clay, and xylene was distilled off under reduced pressure. Thereafter, the residue was purified by column chromatography (developing solvent: chloroform / hexane) to obtain 21.4 g of compound (HT-3) as a solid (yield 72%).
An infrared absorption spectrum chart of the obtained compound (HT-3) is shown in FIG.

( Comparative Example 1-4)
According to the following reaction formula (IIIb), first, compound 4-2 represented by the formula (IIIb) was synthesized, and then HT-4 represented by the formula (IIIb) was synthesized.

That is, instead of the above-mentioned 1-amino-3-[(4-aminophenyl) methyl] benzene (Compound 3-1) used in the synthesis of (iii) HT-3 of Comparative Example 1-3, 1-amino- The compound was prepared in the same manner as in Comparative Example 1-3 except that 6.36 g (0.03 mol) of 2-[(2-aminophenyl) ethyl] benzene (Compound 3-3 in Formula (IIIb)) was used. 13.1 g of 4-2 was obtained. (Yield 73%).
Next, (iii) in Comparative Example 1-3, except that 17.9 g (0.03 mol) of the compound 4-2 obtained above was used instead of the compound 4-1 used in the synthesis of HT-3, It carried out like Comparative Example 1-3 and obtained 21.1g of compounds (HT-4) as a solid (yield 70%).

( Comparative Example 1-5)
According to the following reaction formula (IIIc), first, compound 4-3 represented by the formula (IIIc) was synthesized, and then HT-5 represented by the formula (IIIc) was synthesized.

That is, in place of the 1-amino-3-[(4-aminophenyl) methyl] benzene (compound 3-1) used in the synthesis of (iii) HT-3 of Comparative Example 1-3, 1-amino- Except that 6 g (0.03 mol) of 3- (4-aminophenoxy) benzene (Compound 3-4 in Formula (IIIc)) was used, the same procedure as in Comparative Example 1-3 was carried out, and Compound 4-3 was converted to 13 0.2 g was obtained. (Yield 75%).
Next, (iii) in Comparative Example 1-3, except that 17.5 g (0.03 mol) of the compound 4-3 obtained above was used instead of the compound 4-1 used in the synthesis of HT-3, It carried out like Comparative Example 1-3 and obtained 19.4g of compounds (HT-5) as a solid (yield 65%).
An infrared absorption spectrum chart of the obtained compound (HT-5) is shown in FIG.

(Example 1- 1)
(Iii) Comparative Example 1-1 (iii) In place of Compound 2-1 used in the synthesis of HT-1, 28.9 g (0.12 mol) of Compound 2-3 synthesized in Comparative Example 1-3 was used. Was performed in the same manner as Comparative Example 1-1 to obtain 19.8 g of the compound (HT-6) shown below as a solid (yield 65%).

(Example 1-2 )
(Iii) Comparative Example 1-1 (iii) Instead of Compound 2-1 used in the synthesis of HT-1, 28.9 g (0.12 mol) of Compound 2-3 synthesized in Comparative Example 1-3 was used. Instead of the 1-amino-3-[(4-aminophenyl) methyl] benzene (Compound 3-1), 1-amino-3-[(3-aminophenyl) methyl] benzene (Compound 3- 2) The same operation as in Comparative Example 1-1 was performed except that 5.94 g (0.03 mol) was used, and 20.7 g of the following compound (HT-7) was obtained as a solid (yield: 68%). .

(Example 1-3 )
(Iii) Comparative Example 1-1 (iii) Instead of Compound 2-1 used in the synthesis of HT-1, 28.9 g (0.12 mol) of Compound 2-3 synthesized in Comparative Example 1-3 was used. Instead of the 1-amino-3-[(4-aminophenyl) methyl] benzene (compound 3-1), 1-amino-2-[(2-aminophenyl) ethyl] benzene (in the formula (IIIb)) Compound 3-3) The procedure was the same as Comparative Example 1-1 except that 6.36 g (0.03 mol) was used, and 17.0 g of the following compound (HT-8) was obtained as a solid (yield) 55%).

得られた化合物（ＨＴ−８）の赤外線吸収スペクトルチャートを図４に示す。

FIG. 4 shows an infrared absorption spectrum chart of the obtained compound (HT-8).

[Manufacture of electrophotographic photoreceptors]
(Example 2-1～2- 9, Comparative Example 2-1～2- 21)
As a charge generating material, X using type metal-free phthalocyanine or Y type titanyl phthalocyanine, a hole transport agent, the embodiments obtained in bi string phenylamine derivative (HT-1) ~ (HT -8) or conventional Any one of the above-mentioned butadienylbenzenamine derivative (HT-A) represented by the formula HT-A and a styryl compound (HT-B) represented by the formula HT-B is used as the electron transporting agent. An electrophotographic photosensitive member was produced using an electron transporting agent represented by the following formula ET-1 or the following formula ET-2.

That is, 5 parts by weight of the charge generating agent shown in Table 1, 60 parts by weight of the hole transporting agent shown in Table 1, 25 parts by weight of the electron transporting agent shown in Table 1, and 100 parts by weight of polycarbonate as the binder resin Were mixed and dispersed in a ball mill for 50 hours together with 800 parts by weight of tetrahydrofuran as a solvent to prepare a coating solution for a single-layer type photosensitive layer. Next, this coating solution was applied on a conductive base material (aluminum base tube) by dip coating and dried with hot air at 100 ° C. for 30 minutes to produce a single-layer type photoreceptor having a film thickness of 25 μm.
The following tests were conducted using the obtained photoreceptor to evaluate its performance.
However, Comparative Example 2 16 ～2- 18 with butadienyl benzene derivative (HT-A) as the charge transport agent, since the photosensitive layer was crystallized and could not be evaluated.

(Electrical characteristics test)
Using a GENTEC drum sensitivity tester, it was charged so that the initial surface potential V0 was about +700 V, and then monochromatic light with a wavelength of 780 nm (half-value width 20 nm) extracted from the white light of the halogen lamp using a bandpass filter. , Light intensity of 1.5 μJ / cm ² ) is applied to the surface of the photoreceptor for 1.5 seconds, and the surface potential is measured when 0.5 seconds have elapsed from the start of exposure, and the residual potential VL (V) is measured. It was. This was regarded as one step, and this step was repeated for 500 minutes, and the measured values at the final repetition time were evaluated.

(Elution measurement test)
Only for the photoreceptor obtained in the example using X-type metal-free phthalocyanine as the charge generating agent and ET-2 as the electron transporting agent, the elution amount was measured by the following method. That is, the surface of the photoreceptor (the entire photosensitive layer) was immersed in 200 g of a paraffinic solvent for wet developer (isoparaffin “Isopar G” manufactured by ExxonMobil Chemical Co., Ltd.) at 25 ° C. for 200 hours. The immersion in the paraffinic solvent was performed in a closed system and in a dark place. After 200 hours (after immersion), the UV absorbance of the paraffinic solvent was measured.
On the other hand, the electron transport agent (ET-2) used was dissolved in the paraffinic solvent at various concentrations, and the concentration of the electron transport agent and the UV absorbance at the peak wavelength of the electron transport agent were measured. A calibration curve of concentration-absorbance of the transport agent was prepared. Next, the elution amount (g / cm ³ × 10 ⁻⁷ ) of the electron transport agent was calculated from the obtained calibration curve and the actually measured value of the absorbance of the electron transport agent. It can be said that the smaller the elution amount, the higher the solvent resistance of the photoconductor, and the more suitable the photoconductor for liquid development.
The results are shown in Table 1.

Table 1 As is clear, in the electrophotographic photoreceptor of Comparative Example 2 19 ～2- 21 with HT-B, the residual potential VL is high and found that the amount of elution is inferior to many solvent resistance It was. In Comparative Example 2 16 ～2- 18 with HT-A, as described above, for crystallization, were unable electrical properties, measured with elution amount.
In contrast , the electrophotographic photoreceptors of Examples 2-1 to 2-9 and Comparative Examples 2-1 to 2-15 using HT-1 to HT-8 all have a low residual potential VL and are high. A sensitive electrophotographic photosensitive member could be obtained. Furthermore, since the electrophotographic photoreceptors of Examples 2-1 to 2-9 have a lower elution amount and superior solvent resistance than the electrophotographic photoreceptors of Comparative Examples 2-1 to 2-15, the photosensitive materials for liquid development are used. It was also found to be suitable as a body.

It is an infrared absorption spectrum chart of a bistriphenylamine derivative (HT-1). It is an infrared absorption spectrum chart of a bistriphenylamine derivative (HT-3). It is an infrared absorption spectrum chart of a bistriphenylamine derivative (HT-5). It is an infrared absorption spectrum chart of a bistriphenylamine derivative (HT-8).

Claims (2)

A bistriphenylamine derivative represented by the following general formula (1).

(Wherein R ₁ and R ₂ are each independently a hydrogen atom, aryl group, alkyl group or alkoxy group (wherein the aryl group, alkyl group and alkoxy group each may have a substituent)) Ar ₁ and Ar ₂ are each independently an aryl group, a heterocyclic group or a condensed heterocyclic group (wherein the aryl group, heterocyclic group or condensed heterocyclic group has a substituent, And A represents an alkylene group or an oxygen atom, and n and m are 1. )   An electrophotographic photosensitive member comprising a photosensitive layer containing at least a charge generating agent and a charge transporting agent, wherein the charge transporting agent comprises the bistriphenylamine derivative according to claim 1. body.

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