JP2006267886A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which has alcohol resistance, hardly cracks even when contacting washing alcohol and provides stable images by using specific polycarbonate resin for a photoconductive layer. <P>SOLUTION: The electrophotographic photoreceptor uses, as binder resin for a photosensitive layer, 5 to 100 wt.% polycarbonate resin for all of bisphenol of formula (1), the polycarbonate resin being obtained by subjecting to a reaction with the bisphenol, expressed by formula (1), which has two different substituents bonded to carbon coupling 4-hydroxyphenyl groups, bisphenol expressed by formula (2), and a compound forming carbonic acid ester. Here, R<SB>1</SB>to R<SB>12</SB>are hydrogen, fluorine, chloride, bromine, iodine, an alkyl group with 1-9C, an aryl group with 6-12C, an alkenyl group with 2-5C, an alkoxy group with 1-5C, and an aralkyl group with 7-17C respectively, and substituents that those groups may have at carbons are fluorine, chlorine, bromine, a halogen group selected from iodine, an alkyl group with 1-5C, an alkenyl group with 2-5C, and an alkoxy group with 1-5C. X represents a specific formula. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member. More specifically, the present invention relates to an electrophotographic photoreceptor produced using a specific polycarbonate resin as a binder.

At present, the electrophotographic technology is widely applied to copying machines, laser beam printers (hereinafter abbreviated as LBP), fax machines and the like due to its high speed and high image quality.
Conventionally, inorganic photoconductive materials such as selenium, selenium / tellurium alloys, selenium / arsenic alloys, cadmium sulfide have been mainly used as electrophotographic photoreceptors in this electrophotographic technology. However, recently, an electrophotographic photoreceptor using an organic photoconductive substance has been developed from the viewpoint of toxicity, safety, price, productivity, and the like. When the organic photoconductive substance is a low molecular substance, it is usually performed by mixing with a binder resin to form a coating film. Binder resins include vinyl polymers such as polymethyl methacrylate, polystyrene, polyvinyl chloride and copolymers thereof, various thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy resin, epoxy resin, silicone resin, and thermosetting. Resin is used. Electrophotographic photoreceptors using these various binder resins can be easily formed into thin films by a cast film forming method, are suitable for mass production, and are relatively inexpensive. Of these various resins, polycarbonate resins have relatively excellent characteristics and are often used. It has been reported that various polycarbonate resins are used as the binder resin. Among them, polycarbonate resin derived from 1,1-bis (4-hydroxyphenyl) cyclohexane as a raw material monomer has excellent compatibility with organic photoconductive substances, and excellent solvent solubility and wear resistance. It is used as a binder resin. (See Patent Document 1)

In recent years, the demand for electrophotographic photoreceptors overseas has been increasing, and among them, the electrophotographic photoreceptors may be exposed to unexpected usage environments due to the circumstances of each country. This polycarbonate binder resin from 1,1-bis (4-hydroxyphenyl) cyclohexane is excellent in solvent solubility, but inferior in solvent resistance. In some cases, the surface is eroded by the alcohol cleaning liquid used when wiping off the toner scattered outside the electrophotographic photosensitive member unit, causing cracks and making the toner unusable.
On the other hand, in the electrophotographic photoreceptor manufacturing process, due to environmental problems, the use of halogenated hydrocarbons has been avoided as a solvent, and solvents mainly composed of non-halogen hydrocarbons have become mainstream, and the solvent has a high concentration. Dissolution is a necessary condition for the binder resin.
JP-A-61-62039

  An object of the present invention is to improve the solvent solubility and alcohol resistance of an electrophotographic photoreceptor.

As a result of intensive investigations to solve the conventional problems, the present inventors use, as a binder resin, a polycarbonate resin using bisphenol having two different substituents bonded to the carbon connecting the 4-hydroxyphenyl group. As a result, it has been found that it has good solvent solubility and excellent crack resistance against alcohol, and has completed the present invention.
That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is different in two substituents bonded to carbon connecting a 4-hydroxyphenyl group. Of the polycarbonate resins obtained by reacting the bisphenol represented by the formula (1) and the bisphenol represented by the following general formula (2) with the carbonate ester-forming compound, the general formula (1) is all bisphenols used. The present invention provides an electrophotographic photosensitive member characterized by using 5 to 100% by weight of a polycarbonate resin.

（式中、Ｒ_１〜Ｒ_６は、それぞれ水素、フッ素、塩素、臭素、ヨウ素、炭素数１〜９のアルキル基、炭素数６〜１２のアリール基、炭素数２〜５のアルケニル基、炭素数１〜５のアルコキシ基、炭素数７〜１７のアラルキル基を表し、これらの基の炭素にいずれも有してもよい置換基は、フッ素、塩素、臭素、ヨウ素から選ばれるハロゲン基、炭素数１〜５のアルキル基、炭素数２〜５のアルケニル基、炭素数１〜５のアルコキシ基である。ただし、Ｒ₅とＲ_６は、必ず異なる基を表す。）

(Wherein R _{1 to} R ₆ are each hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and carbon. The substituent which may represent any of the alkoxy groups having 1 to 5 carbon atoms and the aralkyl group having 7 to 17 carbon atoms, which may be contained in any carbon of these groups, is a halogen group selected from fluorine, chlorine, bromine and iodine, carbon An alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, provided that R ₅ and R ₆ always represent different groups.

（式中、Ｒ₇〜Ｒ_１０は、それぞれ水素、フッ素、塩素、臭素、ヨウ素、炭素数１〜９のアルキル基、炭素数６〜１２のアリール基、炭素数２〜５のアルケニル基、炭素数１〜５のアルコキシ基、炭素数７〜１７のアラルキル基を表し、これらの基の炭素にいずれも有してもよい置換基は、フッ素、塩素、臭素、ヨウ素から選ばれるハロゲン基、炭素数１〜５のアルキル基、炭素数２〜５のアルケニル基、炭素数１〜５のアルコキシ基である。Ｘは、

Wherein R _{7 to} R ₁₀ are each hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, carbon The substituent which may represent any of the alkoxy groups having 1 to 5 carbon atoms and the aralkyl group having 7 to 17 carbon atoms, which may be contained in any carbon of these groups, is a halogen group selected from fluorine, chlorine, bromine and iodine, carbon An alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms.

を表し、ここにＲ_１１は、水素、フッ素、塩素、臭素、ヨウ素、炭素数１〜９のアルキル基、炭素数１〜５のアルコキシ基、炭素数６〜１２アリール基を表すか、Ｒ_１１同士が一緒に結合して、炭素数５〜１２の炭素環または元素数５〜１２の複素環を形成する基を表し、これらの基の炭素に有してもよい置換基は、フッ素、塩素、臭素、ヨウ素から選ばれるハロゲン基、炭素数１〜５のアルキル基、炭素数２〜５のアルケニル基、炭素数１〜５のアルコキシ基である。Ｒ_１２は、水素、フッ素、塩素、臭素、ヨウ素、炭素数１〜９のアルキル基、炭素数１〜５のアルコキシ基、炭素数６〜１２アリール基を表し、これらの基の炭素に有してもよい置換基は、フッ素、塩素、臭素、ヨウ素から選ばれるハロゲン基、炭素数１〜５のアルキル基、炭素数２〜５のアルケニル基、炭素数１〜５のアルコキシ基である。Ｒ_１３は置換基を有しても良い１〜９のアルキレン基を表す。ａは０〜２０の整数を表し、ｂは１〜５００の整数を表す。）

Wherein R ₁₁ represents hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, or R ₁₁ The groups which are bonded together to form a carbocyclic ring having 5 to 12 carbon atoms or a heterocyclic ring having 5 to 12 carbon atoms, and the substituents which may be present on the carbon of these groups are fluorine, chlorine , A halogen group selected from bromine and iodine, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. R ₁₂ represents hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the carbon of these groups has The substituent which may be sufficient is a halogen group selected from fluorine, chlorine, bromine and iodine, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms. R ₁₃ represents an alkylene group of 1 to 9 which may have a substituent. a represents an integer of 0 to 20, and b represents an integer of 1 to 500. )

The electrophotographic photoconductor of the present invention is a conventional electrophotographic photoconductor by using, as a binder, a polycarbonate resin derived from bisphenol in which two substituents bonded to carbon connecting a 4-hydroxyphenyl group are different. While maintaining solubility in a non-halogen hydrocarbon solvent equivalent to that of the binder resin, cracks are less likely to occur even when contacted with cleaning alcohol, and a stable image can be obtained. This facilitates maintenance of the copying machine and printer, and is effective in improving workability.

  The electrophotographic photosensitive member of the present invention may have a single photoconductive layer on a conductive support or may be a layered type having separated functions. Recently, a multi-layer electrophotographic photosensitive member having two layers of a charge generation layer that generates charges by exposure and a charge transport layer that transports charges has become mainstream. Moreover, you may provide an undercoat layer, a protective layer, an adhesive layer, etc. as needed.

  The conductive support of the present invention is a metal material such as aluminum, stainless steel or nickel, or a polyester film having a conductive layer such as aluminum, palladium, tin oxide or indium oxide on the surface, phenol resin or paper, etc. Is used.

  The charge generation layer of the present invention is formed on a conductive support by a known method. As the charge generation material, for example, organic pigments such as azoxybenzene, disazo, trisazo, benzimidazole, polycyclic quinoline, indigoid, quinacridone, phthalocyanine, perylene, and methine can be used. . These charge generation materials are made of fine particles such as polyvinyl butyral resin, polyvinyl formal resin, silicone resin, polyamide resin, polyester resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin, polyurethane resin, phenoxy resin, epoxy resin, and various celluloses. Used in a form dispersed in a binder resin.

  The charge transport layer of the present invention is formed by dispersing a charge transport material on the charge generation layer by a known method using the polycarbonate resin of the present invention as a binder resin. Examples of the charge transport material include polytetracyanoethylene; fluorenone compounds such as 2,4,7-trinitro-9-fluorenone; nitro compounds such as dinitroanthracene; succinic anhydride; maleic anhydride; dibromomaleic anhydride; Triphenylmethane compounds; oxadiazole compounds such as 2,5-di (4-dimethylaminophenyl) -1,3,4-oxadiazole; styryl compounds such as 9- (4-diethylaminostyryl) anthracene Carbazole compounds such as poly-N-vinylcarbazole; pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline; 4,4 ′, 4 ″ -tris (N, N-diphenylamino); Triphenylamine, N, N′-bis (3-methylphenyl) -N, N′-bi Amine derivatives such as (phenyl) benzidine; conjugated unsaturated compounds such as 1,1-bis (4-diethylaminophenyl) -4,4-diphenyl-1,3-butadiene; 4- (N, N-diethylamino) benzaldehyde-N Hydrazone compounds such as N-diphenylhydrazone; including indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, pyrazoline compounds, triazole compounds, etc. Examples thereof include nitrogen cyclic compounds, condensed polycyclic compounds, etc. The above charge transport materials may be used alone or in combination.

  The polycarbonate resin of the present invention is a known method used in producing a polycarbonate resin from bisphenol A and a carbonate ester-forming compound, for example, a direct reaction of bisphenol and phosgene (phosgene method), or bisphenol and bisaryl carbonate. A method such as transesterification (transesterification method) can be employed.

In the phosgene method and the transesterification method, the phosgene method is preferable in consideration of the reactivity of the bisphenol of the general formula (1).
Further, from the viewpoint of the physical properties of the polycarbonate resin, it is preferable that the bisphenol of the general formula (1) is used in an amount of 5 to 100% by weight, particularly 40 to 100% by weight, based on the total bisphenol used.

  Specific examples of the bisphenol represented by the general formula (1) used in the production of the polycarbonate resin in the present invention include 1,1-bis (4-hydroxyphenyl) ethane and 1,1-bis (4 -Hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) ) -4-methylpentane, bis (4-hydroxyphenyl) phenylmethane, 1,1-bis (2-methyl-4-hydroxy-5-t-butylphenyl) butane and the like. Two or more of these may be used in combination. Of these, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1- Phenylethane and 2,2-bis (4-hydroxyphenyl) butane are preferable, and 1,1-bis (4-hydroxyphenyl) ethane is more preferable.

  Specific examples of the bisphenol of the general formula (2) of the present invention include 1,1′-biphenyl-4,4′-diol, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, Bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) ketone, 2,2-bis (4-hydroxyphenyl) propane, 2 , 2-bis (4-hydroxy-3-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane, , 1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3-allylph) Nyl) propane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, bis (4-hydroxyphenyl) diphenylmethane, 9,9-bis (4-hydroxyphenyl) fluorene, α, ω-bis [2- ( p-hydroxyphenyl) ethyl] polydimethylsiloxane and the like. Two or more of these may be used in combination. Of these, 1,1′-biphenyl-4,4′-diol, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, and 2,2-bis (4-hydroxyphenyl) propane are particularly preferred. 2,2-bis (4-hydroxy-3-methylphenyl) propane is preferably selected.

  On the other hand, examples of the carbonate ester-forming compound include phosgene, bisallyl carbonate such as diphenyl carbonate, di-p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. Two or more of these compounds can be used in combination.

  In the phosgene method, bisgene of general formula (1) and bisphenol of general formula (2) are reacted with bisphenol, usually in the presence of an acid binder and a solvent. As the acid binder, for example, pyridine, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and the like are used as an aqueous solution. Examples of the solvent include methylene chloride and chloroform. In addition, a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt is used to promote the condensation polymerization reaction. In order to adjust the polymerization degree, it is preferable to add a monofunctional compound such as phenol, pt-butylphenol, p-cumylphenol, or a long-chain alkyl-substituted phenol as a molecular weight regulator. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfite, or a branching agent such as phloroglucin or isatin bisphenol may be added. The reaction is usually in the range of 0 to 150 ° C, preferably 5 to 40 ° C. While the reaction time depends on the reaction temperature, it is generally 0.5 min-10 hr, preferably 1 min-2 hr. Further, during the reaction, it is desirable to maintain the pH of the reaction system at 10 or more.

  On the other hand, in the transesterification method, the bisphenol of the general formula (1) and the bisphenol of the general formula (2) and bisaryl carbonate are mixed and reacted at high temperature under reduced pressure. The reaction is usually carried out at a temperature in the range of 150 to 350 ° C, preferably 200 to 300 ° C. The degree of vacuum is preferably 1 mmHg or less at the end, and phenols derived from the bisaryl carbonate by-produced by the transesterification reaction are distilled out of the system. The reaction time depends on the reaction temperature and the degree of reduced pressure, but is usually about 1 to 10 hours. The reaction is preferably carried out in an inert gas atmosphere such as nitrogen or argon. Moreover, you may react by adding a molecular weight regulator, antioxidant, and a branching agent as needed.

  The polycarbonate resin synthesized by these reactions can be easily molded by known wet molding such as the solution casting method, casting method, spraying method, dip coating method (dip method) used in electrophotographic photosensitive member production. . In order for the electrophotographic photosensitive member formed by wet molding to have sufficient film strength, the intrinsic viscosity is preferably 0.30 to 2.0 dl / g. Further, when emphasizing film formability and film strength, It is preferably 0.40 to 1.5 dl / g.

  Furthermore, when the molecular weight distribution of the obtained polycarbonate resin is represented by the value of weight average molecular weight / number average molecular weight (Mw / Mn) as measured by GPC, it is preferably 4.0 or more. When the molecular weight distribution is less than 4.0, the crack resistance to alcohol tends to be inferior. The polycarbonate resin of the present invention is likely to have a molecular weight distribution of 4.0 or higher, but if it cannot be obtained by synthesis, a low molecular weight product and a high molecular weight product may be blended so that the molecular weight distribution is 4.0 or higher. Is possible.

  The charge generation layer and the charge transport layer are prepared by dissolving the charge generation material or the charge transport material in a binder resin and an appropriate solvent, respectively, applying the solution by a dip coating method or a spray method, and drying. Can be formed. These solvents can be broadly classified into two types, halogen-based organic solvents and non-halogen-based organic solvents. Conventionally, halogen-based solvents with low flammability have been widely used, but in recent years, from the viewpoint of safety and environmental conservation. Therefore, the proportion of non-halogen solvents used is increasing, and the polycarbonate resin used in the present invention is also well soluble in non-halogen solvents.

  Non-halogen solvents in the present invention are aromatic hydrocarbons such as toluene and xylene, ketones such as acetone, methyl ethyl ketone, cyclohexanone and isophorone, ethers such as tetrahydrofuran, dioxane, ethylene glycol diethyl ether and ethyl cellosolve, methyl acetate, Examples include esters such as ethyl acetate, and other dimethylformamide, dimethylsulfoxide, diethylformamide and the like. In the present invention, these solvents can be used alone or in combination of two or more to make a non-halogen solvent. Among these, it is preferable to dissolve in a mixed solvent of toluene and tetrahydrofuran. The mixing ratio of the binder resin in the non-halogen solvent solution of the binder resin is preferably in the range of 1 to 40% by weight when forming the charge transport layer binder resin.

  The mixing ratio of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:20. The charge generation layer has a thickness of 0.01 to 20 μm, preferably 0.1 to 2 μm. The mixing ratio of the charge transport material and the binder resin is preferably in the range of 10: 1 to 1:10. The thickness of the charge transport layer is 2 to 100 μm, preferably 5 to 30 μm.

800 ml of 8 w / w% sodium hydroxide aqueous solution, 100 g (0.47 mol) of 1,1-bis (4-hydroxyphenyl) ethane (Honshu Chemical Industry Co., Ltd., hereinafter abbreviated as BPE) and hydrosulfite 0 .1 g was dissolved.
To this, 400 ml of methylene chloride was added and stirred. While maintaining the temperature at 15 ° C., 60 g of phosgene was blown in over 60 minutes.
After the completion of phosgene blowing, 1.55 g of pt-butylphenol (hereinafter abbreviated as PTBP) was added and stirred vigorously to emulsify the reaction solution. After emulsification, 0.3 ml of triethylamine was added, and 20-25 ° C. For about 1 hour to polymerize.
After completion of the polymerization, the reaction solution was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and washing with water was repeated until the conductivity of the previous solution (aqueous phase) became 10 μS / cm or less. The obtained polymer solution was dropped into warm water maintained at 45 ° C., and the solvent was removed by evaporation to obtain a white powdery precipitate.
The obtained precipitate was filtered and dried at 105 ° C. for 24 hours to obtain a polymer powder.
The intrinsic viscosity at 20 ° C. of a 0.5 g / dl concentration solution of this polymer using methylene chloride as a solvent was 0.81 dl / g. The results obtained polymer was analyzed by infrared absorption spectrum, absorption by carbonyl group at the position in the vicinity of 1770 cm ^-1, observed absorption by ether bond position near 1240 cm ^-1, it is polycarbonate resin having a carbonate bond Was confirmed. The weight average molecular weight (Mw) in terms of styrene by GPC measurement of this polymer was 90300, the number average molecular weight (Mn) was 17000, and the molecular weight distribution (Mw / Mn) was 5.31.

Next, 50 parts by weight of N, N′-bis (3-methylphenyl) -N, N′-bis (phenyl) benzidine (manufactured by SYNTEC, ST16 / 1.2) and a polycarbonate resin obtained by the above synthetic polymerization 50 parts by weight of tetrahydrofuran, 50 parts by weight of tetrahydrofuran and 300 parts by weight of toluene were mixed to prepare a coating solution, and the coating solution was applied to a commercially available LBP photoreceptor (manufactured by Epson Corporation, LPA3ETC4) from which the charge transport layer was previously removed with tetrahydrofuran. After being air-dried, it was dried at 100 ° C. for 8 hours, and a charge transport layer having a thickness of about 20 μm was provided to produce a multilayer electrophotographic photosensitive member.
A special grade ethanol (manufactured by Wako Pure Chemical Industries, Ltd.) and a commercially available alcohol-based OA cleaner (manufactured by Plus Co., Ltd.) with a cotton swab on the surface of the photoconductor that is approximately 2 cm in the circumferential direction and about 3 cm in the cylindrical direction. Two types of OC-005) were applied to different places and allowed to stand for 24 hours.
After leaving, the printed paper image missing on the ethanol coated surface after continuous black printing of 50 continuous sheets and the presence or absence of cracks on the photoreceptor were observed visually and with a microscope. The results are shown in Table 1.

  Instead of using 100 g of BPE, 50 g (0.23 mol) of BPE and 50 g (0.25 mol) of bis (4-hydroxyphenyl) ether (Dainippon Ink Chemical Co., Ltd., hereinafter abbreviated as DHPE) were used. Was synthesized in the same manner as in Example 1. The intrinsic viscosity of the obtained polycarbonate resin was 0.78 dl / g. Moreover, Mw was 88100, Mn was 17200, and Mw / Mn was 5.12. Using the synthesized polycarbonate resin, electrophotographic photosensitive member molding and performance evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.

  Instead of 100 g of BPE, 80 g (0.37 mol) of BPE and 20 g (0.11 mol) of 1,1′-biphenyl-4,4′-diol (Honshu Chemical Industry Co., Ltd., hereinafter abbreviated as BP) are used. The synthesis was performed in the same manner as in Example 1 except that it was used. The intrinsic viscosity of the obtained polycarbonate resin was 0.85 dl / g. Moreover, Mw was 93400, Mn was 16700, and Mw / Mn was 5.59. Using the synthesized polycarbonate resin, electrophotographic photosensitive member molding and performance evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.

  Instead of 100 g of BPE, 70 g (0.33 mol) of BPE and 30 g (0. 3) of 2,2-bis (4-hydroxy-3-methylphenyl) propane (Honshu Chemical Industry Co., Ltd., hereinafter abbreviated as BPC). Synthesis was performed in the same manner as in Example 1 except that 12 mol) was used. The intrinsic viscosity of the obtained polycarbonate resin was 0.83 dl / g. Moreover, Mw was 92100, Mn was 17200, and Mw / Mn was 5.35. Using the synthesized polycarbonate resin, electrophotographic photosensitive member molding and performance evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.

    Instead of 100 g of BPE, 1,1-bis (4-hydroxy-3-methylphenyl) ethane (manufactured by Asahi Organic Materials Co., Ltd., hereinafter abbreviated as DMBPE) 80 g (0.33 mol) and 2,2-bis Synthesis was performed in the same manner as in Example 1 except that 20 g (0.09 mol) of (4-hydroxyphenyl) propane (Mitsui Chemicals, Inc., hereinafter abbreviated as BPA) was used. The intrinsic viscosity of the obtained polycarbonate resin was 0.86 dl / g. Moreover, Mw was 94300, Mn was 18900, and Mw / Mn was 4.99. Using the synthesized polycarbonate resin, electrophotographic photosensitive member molding and performance evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.

  Instead of 100 g of BPE, 2,2-bis (4-hydroxyphenyl) butane (manufactured by Honshu Chemical Industry Co., Ltd., hereinafter abbreviated as BPB) 60 g (0.25 mol), 1,1-bis (4-hydroxyphenyl) ) -1-Phenylethane (manufactured by Honshu Chemical Industry Co., Ltd., hereinafter abbreviated as BPAP) 20 g (0.07 mol) and BPA 20 g (0.09 mol) were used, except that the PTBP amount was changed to 0.62 g. Synthesis was carried out in the same manner as in Example 1. The intrinsic viscosity of the obtained polycarbonate resin was 1.3 dl / g. Moreover, Mw was 178000, Mn was 20800, and Mw / Mn was 8.56. Using the synthesized polycarbonate resin, electrophotographic photosensitive member molding and performance evaluation were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
Instead of the polycarbonate resin of Example 1, a commercially available binder resin for electrophotographic photoreceptors, BPZ type homopolycarbonate resin (PCZ-400 manufactured by Mitsubishi Engineering Plastics Co., Ltd., intrinsic viscosity 0.75 dl / g, Mw / Mn = 3.72), the same electrophotographic photosensitive member molding and performance evaluation as in Example 1 were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
Instead of the polycarbonate resin of Example 1, using a commercially available BPA type homopolycarbonate resin (Iupilon K-4000 manufactured by Mitsubishi Engineering Plastics Co., Ltd., intrinsic viscosity 0.78 dl / g, Mw / Mn = 2.81), The same electrophotographic photosensitive member molding and performance evaluation as in Example 1 were attempted in the same manner as in Example 1, but the film could not be formed due to insufficient dissolution in a solvent. The results are shown in Table 1.

(Comparative Example 3)
Instead of the polycarbonate resin of Example 1, a commercially available binder resin for electrophotographic photoreceptors, a BPZ type homopolycarbonate resin (PCZ-800 manufactured by Mitsubishi Engineering Plastics Co., Ltd., intrinsic viscosity 1.35 dl / g, Mw / Mn = 7.89), the same electrophotographic photosensitive member molding and performance evaluation as in Example 1 were performed in the same manner as in Example 1. The results are shown in Table 1.

(Explanation of symbols in Table 1)
Bisphenol component: Ratio of each bisphenol to the total bisphenol component (% by weight)
BPE: 1,1-bis (4-hydroxyphenyl) ethane DHPE: bis (4-hydroxyphenyl) ethane BP: 1,1′-biphenyl-4,4′-diol BPC: 2,2-bis (4-hydroxy) -3-methylphenyl) propane BPA: 2,2-bis (4-hydroxyphenyl) propane DMBPE: 1,1-bis (4-hydroxy-3-methylphenyl) ethane BPB: 2,2-bis (4-hydroxy) Phenyl) butane BPAP: 1,1-bis (4-hydroxyphenyl) -1-phenylethane BPZ: 1,1-bis (4-hydroxyphenyl) cyclohexane solvent solubility: 5 g of each polycarbonate resin is 5 g of tetrahydrofuran and 30 g of toluene. Judged by whether or not to dissolve in the mixed solution.
Intrinsic viscosity: Ubbelohde viscosity tube is used. Measured at 20 ° C., 0.5% dichloromethane solution, and Huggins constant of 0.45.
Image missing: Visual determination of the presence or absence of an image with a diameter of 1 mm or more during black printing of 50 continuous A4 paper.
Crack: Visual determination of the presence or absence of a crack with a 100 times digital microscope.
GPC molecular weight distribution: using a GPC measuring apparatus manufactured by Water. Columns are 2 Shodex K-805L manufactured by Showa Denko KK Flow rate 1 ml / min. Chloroform eluent. Sample concentration 0.25 wt / vol% chloroform solution. Measured with a UV detector at a wavelength of 254 nm. The molecular weight distribution was expressed in terms of weight average molecular weight / number average molecular weight in terms of styrene equivalent molecular weight.

Claims (7)

In an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, the binder resin of the photosensitive layer is represented by the following general formula (1) in which two substituents bonded to carbon connecting a 4-hydroxyphenyl group are different. Among the polycarbonate resins obtained by reacting bisphenols represented by the following general formula (2) with carbonate ester-forming compounds, the general formula (1) is 5 to 100 wt. % Of an electrophotographic photosensitive member using a polycarbonate resin.

(Wherein R _{1 to} R ₆ are each hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and carbon. The substituent which may represent any of the alkoxy groups having 1 to 5 carbon atoms and the aralkyl group having 7 to 17 carbon atoms, which may be contained in any carbon of these groups, is a halogen group selected from fluorine, chlorine, bromine and iodine, carbon An alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms, provided that R ₅ and R ₆ always represent different groups.

Wherein R _{7 to} R ₁₀ are each hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, carbon The substituent which may represent any of the alkoxy groups having 1 to 5 carbon atoms and the aralkyl group having 7 to 17 carbon atoms, which may be contained in any carbon of these groups, is a halogen group selected from fluorine, chlorine, bromine and iodine, carbon An alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms.

Wherein R ₁₁ represents hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, or R ₁₁ The groups which are bonded together to form a carbocyclic ring having 5 to 12 carbon atoms or a heterocyclic ring having 5 to 12 carbon atoms, and the substituents which may be present on the carbon of these groups are fluorine, chlorine , A halogen group selected from bromine and iodine, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. R ₁₂ represents hydrogen, fluorine, chlorine, bromine, iodine, an alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and the carbon of these groups has The substituent which may be sufficient is a halogen group selected from fluorine, chlorine, bromine and iodine, an alkyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms and an alkoxy group having 1 to 5 carbon atoms. R ₁₃ represents an alkylene group of 1 to 9 which may have a substituent. a represents an integer of 0 to 20, and b represents an integer of 1 to 500. ) General formula (1) is 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxy-3-methylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1 2. The electrophotographic photosensitive member according to claim 1, which is at least one selected from the group consisting of bisphenols consisting of phenylethane and 2,2-bis (4-hydroxyphenyl) butane. The general formula (2) is 1,1′-biphenyl-4,4′-diol, bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, 2,2-bis (4-hydroxyphenyl). 2. The electrophotographic photoreceptor according to claim 1, which is at least one selected from the group of bisphenols consisting of propane and 2,2-bis (4-hydroxy-3-methylphenyl) propane. 2. The electrophotographic photoreceptor according to claim 1, wherein 1,1-bis (4-hydroxyphenyl) ethane is 50% by weight or more in all bisphenols used. The electrophotographic photosensitive member according to claim 1, wherein the carbonate forming compound is phosgene. 2. The electrophotographic photosensitive member according to claim 1, wherein the molecular weight distribution measured by GPC is 4.0 or more. The electrophotographic photosensitive member according to claim 1, wherein the binder resin is used in a charge transport layer of the laminated electrophotographic photosensitive member.