JP5211469B2 - Electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to a polyarylate resin, a process for producing the same, and an electrophotographic photosensitive member using the same, and more particularly, polyarylate obtained by an interfacial polycondensation reaction of an aromatic dicarboxylic acid component and an aromatic dihydric alcohol component. A polyarylate resin having a carboxylic acid halide terminal contained in the polyarylate resin in a weight ratio of 10 ppm or less with respect to the polyarylate resin, a production method thereof, and the polyarylate The present invention relates to an electrophotographic photoreceptor comprising a resin as a binder resin for a photosensitive layer.

  In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high quality images. Since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, transfer, cleaning, static elimination, etc., it is deteriorated by various stresses during that time. Such deterioration includes, for example, strong oxidative ozone and NOx generated from a corona charger normally used as a charger, which causes chemical damage to the photosensitive layer, and carriers (current) generated by image exposure in the photosensitive layer. There are chemical and electrical degradations due to flowing, static elimination light, decomposition of the photosensitive layer composition by external light, and the like.

  Further, there is mechanical deterioration such as abrasion of the photosensitive layer surface due to rubbing of a cleaning blade, a magnetic brush or the like, contact with a developer or paper, generation of scratches, and film peeling. In particular, such damage on the surface of the photosensitive layer tends to appear on the copy image, and directly impairs the image quality, which is a major factor limiting the life of the photoreceptor. That is, in order to develop a long-life photoconductor, it is essential to increase the mechanical strength as well as the electrical and chemical durability.

  In general, in the case of a multilayer photoreceptor, it is the charge transfer layer that receives such a load. The charge transfer layer is usually composed of a binder resin and a charge transfer material, and it is the binder resin that substantially determines the strength, but the amount of the charge transfer material doped is so large that it does not have sufficient mechanical strength. . Conventional binder resins for charge transfer layers of electrophotographic photoreceptors include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polysulfone, phenoxy, epoxy, silicone resin, etc. These thermoplastic resins and various thermosetting resins have been used.

  Among the various binder resins, the polycarbonate resin has relatively excellent performance, and various polycarbonate resins have been developed and put into practical use. For example, Patent Document 1 discloses a bisphenol P-type polycarbonate, Patent Document 2 discloses a bisphenol Z-type polycarbonate, and Patent Document 3 discloses a copolymer of bisphenol P and bisphenol A as a binder resin. Yes.

  On the other hand, Patent Document 4 discloses a technique of an electrophotographic photosensitive member using a polyarylate (aromatic polyester) resin marketed under the trade name “U-polymer” as a binder, and compared with polycarbonate. It is shown that the sensitivity is particularly excellent. Further, Patent Document 5 discloses a copolymer type polyarylate resin in which the commercially available polyarylate resin “U-polymer” has improved coating solution stability, slipperiness, and the like.

JP 50-098332 A JP 59-071057 A JP 59-184251 JP-A-56-135844 JP 2003-76039 A

  However, the conventional organic photoreceptor using the polycarbonate resin reported in Patent Documents 1 to 3 described above as a binder resin is practically used for development with toner, friction with paper, friction with a cleaning member (blade), and the like. However, the present situation is that the printing performance is limited in practical use because the surface is worn or the surface is scratched by the load.

  In addition, these polyarylate resins reported in Patent Document 4 and Patent Document 5 are conventionally prepared by mixing an organic solvent solution of an aromatic dicarboxylic acid component and an alkaline aqueous solution of an aromatic dihydric alcohol component with stirring. It is obtained. The terminal of this polyarylate has a carboxylic acid halide or a carboxylic acid terminal and a phenol terminal. In particular, when a carboxylic acid terminal is present, the residual halogen causes the valence to easily escape in an electrophotographic photoreceptor. As a result, problems such as deterioration of the charging rate and the necessity of a high grid voltage arise. Therefore, it is desirable that the amount of residual halogen is small.

On the other hand, if an unreacted aromatic dihydric alcohol component remains in the resin, the aromatic dihydric alcohol component is oxidized and the color of the resin is deteriorated. It is not preferable that the dihydric alcohol component remains.
The polyarylate resin currently used as a binder resin for electrophotographic photosensitive members is synthesized by interfacial polymerization of an organic solvent solution of an aromatic dicarboxylic acid component and an alkaline aqueous solution of an aromatic dihydric alcohol component with stirring. Yes. For this reason, residual chlorine derived from carboxylic acid halide tends to remain.

The present invention has been made in view of such a situation.
That is, an object of the present invention is to provide a polyarylate resin having a small amount of residual halogen derived from a carboxylic acid halide end during interfacial polymerization of polyarylate.
Another object of the present invention is to provide a method for producing a polyarylate resin.
Furthermore, another object of the present invention is to provide an electrophotographic photoreceptor using a polyarylate resin as a binder resin.

  As a result of intensive studies to solve the above problems, the present inventors have obtained polyarylate by interfacial polymerization using an organic solvent solution of an aromatic dicarboxylic acid component and an alkaline aqueous solution of an aromatic dihydric alcohol component. In the production, by satisfying both of changing the polymer concentration during the polymerization and controlling the addition amount and the addition timing using two or more kinds of specific catalysts, residual halogen derived from the carboxylic acid halide terminal at the end of the polymerization. It has been found that a small amount of polyarylate resin can be produced. In particular, it has been found that an electrophotographic photoreceptor using a polyarylate resin having a carboxylic acid halide terminal of 10 ppm or less as a binder resin exhibits excellent electrical characteristics, and has completed the present invention.

Thus, according to the present invention, the following (1) to ( 9 ) are provided.
(1) In an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, and the photosensitive layer containing a polyarylate resin, the polyarylate resin is an interface between an aromatic dicarboxylic acid component and an aromatic dihydric alcohol component. A polyarylate resin obtained by a polycondensation reaction, wherein the carboxylic acid halide terminal represented by the following general formula (1) contained in the polyarylate resin is 10 ppm or less by weight with respect to the polyarylate resin. an electrophotographic photosensitive member, characterized in that it contains a.

[In General Formula (1), PAR represents a polyarylate chain, and X represents a halogen atom. ]
(2) the poly halogen atom with a carboxylic acid halide terminated in polyarylate resin, electrophotographic photosensitive member according to the which is a chlorine atom (1).
(3) The polyarylate resin has a repeating unit represented by the following general formula (2), and uses one type of aromatic dicarboxylic acid halide and two or more types of dihydric phenol components. The electrophotographic photosensitive member according to (1) or (2) .

[In General Formula (2), R ₁ to R ₈ each independently represent a hydrogen atom or any hydrocarbon group having 1 or more carbon atoms, and X represents a single bond, an oxygen bond, a sulfur bond, an alkylene group, or an alkylidene. Selected from the group consisting of a group, a phenylalkylidene group and a cyclic hydrocarbon group, and Y is selected from the group consisting of a phenylene group, a biphenylene group, a naphthylene group, an aliphatic hydrocarbon group and a cyclic hydrocarbon group. ]
(4) Terephthalic acid dichloride is used as the aromatic dicarboxylic acid component of the polyarylate resin, and a dihydric phenol represented by the following structural formula (A) and the following general formula (3) is used as a dihydric phenol component. The electrophotographic photosensitive member according to (3) .

(General formula (3) is one or more mixtures selected from the group represented by the following structural formula (B), structural formula (C), and structural formula (D).)

(5) In producing a polyarylate resin in which an organic solvent solution of an aromatic dicarboxylic acid component and an alkaline aqueous solution of an aromatic dihydric alcohol component are reacted by interfacial polymerization, the polymer concentration in the organic solvent is changed between the initial polymerization period and the late polymerization period. A method for producing a polyarylate resin, characterized in that a quaternary ammonium salt is added as a catalyst in the early stage of polymerization and a tertiary amine is added as an auxiliary catalyst in the late stage of polymerization.
(6) In the method for producing a polyarylate resin according to (5), 1.0 mol% to 1.5 mol% of a quaternary ammonium salt is used as a catalyst with respect to an aromatic dihydric alcohol component at the initial stage of polymerization, The production of the polyarylate resin according to (1), wherein a tertiary amine is added as an auxiliary catalyst in the latter stage of polymerization in an amount of 0.3 mol% to 1.5 mol% with respect to the aromatic dihydric alcohol component. Method.
(7) The method for producing a polyarylate resin according to (5) to (6), wherein the polymerization reaction is performed at 15 ° C. or higher.
(8) The method for producing a polyarylate resin according to (7), wherein the polymerization reaction is performed at 15 ° C. to 40 ° C.
(9) In an electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, the binder resin for the photosensitive layer is obtained by using the method for producing a polyarylate resin described in (5) to (8) above. polyarylate electrostatic you, wherein the resin is a child photoreceptor.

  The polyarylate resin obtained by the present invention has few carboxylic acid halide terminals and has excellent electrical characteristics when used as an electrophotographic photoreceptor.

The best mode for carrying out the present invention (hereinafter, an embodiment of the present invention) will be described in detail below. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the invention.
A polyarylate resin is used as the binder resin for the electrophotographic photosensitive member to which the exemplary embodiment is applied. The polyarylate resin is an aromatic polyester substantially composed of an aromatic dicarboxylic acid component and an aromatic dihydric alcohol component, and has few carboxylic acid halide terminals present in the polyarylate resin.
More specifically, the carboxylic acid halide terminal represented by the following general formula (1) contained in the polyarylate resin needs to be 10 ppm or less. There are various methods for achieving this carboxylic acid halide terminal of 10 ppm or less. The polymer concentration contained in the organic solvent during the reaction is adjusted, the type of the catalyst used is specified, the order of use of the catalyst, and the like. It is particularly effective to change the polymer concentration during the polymerization and to use the catalyst and the auxiliary catalyst in combination. . Further, the interfacial polymerization reaction is preferably carried out at 15 ° C. or higher, and preferably 40 ° C. or lower in order to obtain a polyarylate resin having a large molecular weight.

  In the general formula (1), PAR represents a polyarylate chain, and X represents a halogen atom.

<Polyarylate resin>
The quantification method of the carboxylic acid halide terminal represented by the general formula (1) contained in the polyarylate resin is obtained by measuring the carboxylic acid halide group. About 1 g of polyarylate resin was precisely weighed, and 20 mL of methylene chloride was added and dissolved. To this was added 2 mL of a 1% by weight methylene chloride solution of 4- (p-nitrobenzyl) pyridine (Wako Pure Chemicals, reagent grade) to develop a color, and about 440 nm using a spectrophotometer (manufactured by Shimadzu Corporation, UV-1600). Absorbance at the wavelength of was measured. Separately, phenylchloroformate or a methylene chloride solution of the carboxylic acid dihalide was used to determine the extinction coefficient, and the amount of trace halogen derived from the carboxylic acid halide group in the sample was quantified. The lower limit of quantification was 0.2 ppm versus solid content in terms of chlorine content.

  In this measurement method, free halogen atoms present in the polyarylate resin are not observed. Therefore, the value obtained by this measurement is purely only for the carboxylic acid halide terminal present in the polyarylate resin.

The viscosity average molecular weight of the polyarylate resin was measured by first dissolving the polyarylate resin in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Next, using a Ubbelohde capillary viscometer, the flow time t ₀ of the solvent (dichloromethane) and the flow time t of the sample solution were measured in a constant temperature water bath set to 20.0 ° C. And the viscosity average molecular weight Mv was computed according to the following formula | equation.
a = (0.28 × η _sp ) +1
b = 10 × (η _sp / C)
η _sp = (t / t ₀ ) −1
C = 6.00 (g / L)
η = (b / a)
Mv = 51400 × [η] exp 1.205

  Examples of the aromatic dihydric alcohol component constituting the polyarylate resin include a dihydric phenol component and a dihydric naphthol component, but a dihydric phenol component is preferable, and the dihydric phenol component is represented by the structural formula (A). Bis (3,5-dimethyl-4-hydroxyphenyl) methane shown and bis (hydroxyphenyl) methane shown by the general formula (2) [bis (2-hydroxyphenyl) methane shown by the structural formula (B) One or a mixture of (2-hydroxyphenyl) (4-hydroxyphenyl) methane represented by the structural formula (C) and bis (4-hydroxyphenyl) methane represented by the structural formula (D) ] Is preferably used. All or part of the dihydric phenol described above may be replaced with another dihydric phenol within a range that does not substantially impair its properties.

  Specific examples of the dihydric phenol component that can be replaced are as follows. For example, 1,1-bis (4-hydroxyphenyl) ethane, bis (4-methyl-2-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3 5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2,2-bis (3-phenyl-4-hydroxyphenyl) propane,

Bis (3-methyl-4-hydroxyphenyl) methane, 4,4′-biphenol, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) -2-methylpropane, Bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxyphenyl) octane, 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane, 2,2-bis (3-allyl-) 4-hydroxyphenyl) propane, 2,2-bis (3-isopropyl-4-hydroxyphenyl) propane, 2,2-bis (3-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (3 -Sec-butyl-4-hydroxyphenyl) propane, bisphenolfluorene, 1,1-bis (2-methyl-4-hydro) Shi -5-tert-butylphenyl) -2-methylpropane,

4,4 ′-[1,4-phenylene-bis (2-propylidene) -bis (3-methyl-4-hydroxyphenyl)], 1,1-bis (3-phenyl-4-hydroxyphenyl) cyclohexane, 4 , 4′-dihydroxyphenyl ether, bis (2-hydroxyphenyl) methane, 2,4′-methylenebisphenol, bis (3-methyl-4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) propane 1,1-bis (2-hydroxy-5-methylphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -3-methyl-butane, bis (2-hydroxy-3,5-dimethylphenyl) methane 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (3-methyl-4-hydroxyphenyl) cyclo Tantalum, 3,3-bis (4-hydroxyphenyl) pentane, 3,3-bis (3-methyl-4-hydroxyphenyl) pentane, 3,3-bis (3,5-dimethyl-4-hydroxyphenyl) pentane ,

2,2-bis (2-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxyphenyl) nonane, 1,1-bis (3-methyl-4-hydroxyphenyl) -1- Phenylethane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) decane, 1,1-bis (4-hydroxyphenyl) decane, bis ( 2-hydroxy-3-tert-butyl-5-methylphenyl) methane, bis (4-hydroxyphenyl) diphenylmethane, terpene diphenol, 1,1-bis (3-tert-butyl-4-hydroxyphenyl) cyclohexane, 1 , 1-bis (2-methyl-4-hydroxy-5-tert-butylphenyl) -2-methylpropane, 2,2 Bis (3-cyclohexyl-4-hydroxyphenyl) propane,

Bis (3,5-di-tert-butyl-4-hydroxyphenyl) methane, bis (3,5-di-sec-butyl-4-hydroxyphenyl) methane, 1,1-bis (3-cyclohexyl-4-) Hydroxyphenyl) cyclohexane, 1,1-bis (2-hydroxy-3,5-di-tert-butylphenyl) ethane, 1,1-bis (3-nonyl-4-hydroxyphenyl) methane, 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, bis (2-hydroxy-3,5-di-tert-butyl-6-methylphenyl) methane, 1,1-bis (3-phenyl) -4-hydroxyphenyl) -1-phenylethane,

4,4-bis (4-hydroxyphenyl) pentanoic acid, α, α′-bis (4-hydroxyphenyl) acetic acid butyl ester, bis (3-fluoro-4-hydroxyphenyl) methane, bis (2-hydroxy-5) -Fluorophenyl) methane, 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane, 1,1-bis (3-fluoro-4-hydroxyphenyl)- 1-phenylmethane, 1,1-bis (3-fluoro-4-hydroxyphenyl) -1- (p-fluorophenyl) methane, 1,1-bis (4-hydroxyphenyl) -1- (p-fluorophenyl) ) Methane, 2,2-bis (3-chloro-4-hydroxy-5-methylphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) ) Propane, 2,2-bis (3-chloro-4-hydroxyphenyl) propane,

Bis (3,5-dibromo-4-hydroxyphenyl) methane, 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane, 2,2-bis (3-nitro-4-hydroxyphenyl) propane 3,3′-dimethyl-4,4′-biphenol, 3,3 ′, 5,5′-tetramethyl-4,4′-biphenol, 3,3 ′, 5,5′-tetra-tert-butyl -4,4'-biphenol, bis (4-hydroxyphenyl) ketone, 3,3'-difluoro-4,4'-biphenol, 3,3 ', 5,5'-tetrafluoro-4,4'-biphenol ,

Bis (4-hydroxyphenyl) dimethylsilane, bis (4-hydroxyphenyl) sulfone, bis (3-methyl-4-hydroxyphenyl) sulfone, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, bis (3 , 5-Dibromo-4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) thioether, bis (3-methyl-4-hydroxyphenyl) ether, bis (3-methyl-4-hydroxyphenyl) thioether, bis (3 , 5-dimethyl-4-hydroxyphenyl) ether, bis (3,5-dimethyl-4-hydroxyphenyl) thioether, 1,1-bis (2,3,5-trimethyl-4-hydroxyphenyl) -1-phenyl Methane, 2,2-bis (3-methyl-4-hydroxyphenyl) dodeca 2,2-bis (3-methyl-4-hydroxyphenyl) dodecane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) dodecane, 1,1-bis (3-tert-butyl-4) -Hydroxyphenyl) -1-phenylethane, 1,1-bis (3,5-di-tert-butyl-4-hydroxyphenyl) -1-phenylethane, 1,1-bis (2-methyl-4-hydroxy) -5-cyclohexylphenyl) -2-methylpropane, 1,1-bis (2-hydroxy-3,5-di-tert-butylphenyl) ethane,

2,2-bis (4-hydroxyphenyl) propanoic acid methyl ester, 2,2-bis (4-hydroxyphenyl) propanoic acid ethyl ester, itisan bisphenol, itisan biscresol, 2,2 ′, 3,3 ′, 5 , 5′-hexamethyl-4,4′-biphenol, bis (2-hydroxyphenyl) methane, 2,4′-methylenebisphenol, 1,2-bis (4-hydroxyphenyl) ethane, 2- (4-hydroxyphenyl) ) -2- (2-hydroxyphenyl) propane, bis (2-hydroxy-3-allylphenyl) methane, 1,1-bis (2-hydroxy-3,5-dimethylphenyl) -2-methylpropane, 1, 1-bis (2-hydroxy-5-tert-butylphenyl) ethane, bis (2-hydroxy-5-phenylphenyl) ) Methane, 1,1-bis (2-methyl-4-hydroxy -5-tert-butylphenyl) butane, bis (2-methyl-4-hydroxy-5-phenyl) methane,

2,2-bis (4-hydroxyphenyl) pentadecane, 2,2-bis (3-methyl-4-hydroxyphenyl) pentadecane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) pentadecane, , 2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) ethane, bis (2-hydroxy-3,5-di-tert-butylphenyl) methane, 2,2-bis (3-styryl) -4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1- (p-nitrophenyl) ethane, bis (3,5-difluoro-4-hydroxyphenyl) methane, bis (3,5 -Difluoro-4-hydroxyphenyl) phenylmethane, bis (3,5-difluoro-4-hydroxyphenyl) diphenylmethane, bis (3 Fluoro-4-hydroxyphenyl) diphenylmethane, 3,3 ', 5,5'-tetra -tert- butyl-2,2'-biphenol,

2,2′-diallyl-4,4′-biphenol, 1,1-bis (4-hydroxyphenyl) -3,3-dimethyl-5-methylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3 , 3,5,5-tetramethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,4-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3-dimethyl- 5-ethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclopentane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -3,3,5 -Trimethylcyclohexane, 1,1-bis (3,5-diphenyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-me 4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3-phenyl-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3 5-dichloro-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (3,5-dibromo-4-hydroxyphenyl) -3,3,5-trimethylcyclohexane,

Resorcinol, hydroquinone, 1,2-hydroxybenzene, 1,4-bis (4-hydroxyphenyl) -p-menthane, 1,4-bis (3-methyl-4-hydroxyphenyl) -p-menthane, 1,4 Examples include terpene diphenols such as -bis (3,5-dimethyl-4-hydroxyphenyl) -p-menthane. These dihydric phenols are used in combination of two kinds, but can be used alone or in combination of three or more kinds.

  Moreover, you may replace a part of dihydric phenol mentioned above with other dihydric alcohols in the range which does not impair the characteristic substantially. Examples of such dihydric alcohols include ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, dodecanediol, neopentylglycol, cyclohexanediol, and 1,4-dihydroxymethylcyclohexane. be able to.

  The aromatic dicarboxylic acid component constituting the polyarylate resin may be any known one as long as it can be used for polyarylate. For example, 1 to 2 alkyl groups such as isophthalic acid, orthophthalic acid, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group Substituted phthalic acid derivatives; naphthalene dicarboxylic acid derivatives such as 1,5-naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid; 4,4′-dicarboxydiphenyl ether, bis (p-carboxyphenyl) alkane, 4, Halides such as 4′-dicarboxydiphenyl sulfone can be mentioned. These aromatic dicarboxylic acid components are preferably used as aromatic dicarboxylic acid halides, and may be used alone or in combination of two or more. Among these, it is preferable to use terephthalic acid dichloride.

  Further, a part of the aromatic dicarboxylic acid halide described above may be replaced with other aliphatic dicarboxylic acid dihalides as long as the properties are not substantially impaired. Examples of such dicarboxylic acid dihalides include dicarboxymethylcyclohexane, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, glutaric acid, and dodecanedioic acid. These halides include chlorine, bromine and the like, but chlorine is preferred.

  The end of the polyarylate resin is phenol, o, m, p-cresol, dimethylphenol, trimethylphenol, o, m, p-ethylphenol, o, m, pn-propylphenol, o, m, p -Monohydric phenol such as isopropylphenol, o, m, p-n-butylphenol, o, m, p-isobutylphenol, o, m, p-sec-butylphenol, o, m, p-tert-butylphenol; methanol, Monovalent alcohols such as ethanol, n-propanol, isopropanol, butanol, pentanol, hexanol, dodecyl alcohol, stearyl alcohol, benzyl alcohol, phenethyl alcohol; acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid, p- Methoxyfe Monovalent carboxylic acids, such as Le acid; benzoic acid chloride, methanesulfonyl chloride, or may be blocked with acid chlorides such as phenyl chloroformate. These compounds function as molecular weight regulators, and 2,3,6-trimethylphenol is particularly preferred because of its high molecular weight adjustment function.

(Method for producing polyarylate resin)
Next, the manufacturing method of the polyarylate resin to which this Embodiment is applied is demonstrated. The polyarylate resin in the present embodiment is performed by reacting an alkaline aqueous solution in which an aromatic dihydric alcohol is dissolved with an organic solvent solution of an aromatic dicarboxylic acid halide in the presence of a polymerization catalyst. At this time, the molar ratio of the raw acid halide group to the phenolic hydroxyl group is set to 1.006 or more, and an auxiliary catalyst is used in the latter stage of the polymerization to control the terminal amount of the carboxylic acid halide present in the polyarylate resin. is necessary.

  The molar ratio between the acid halide group and the phenolic hydroxyl group is preferably from 1.006 to 1.025, more preferably from 1.020 to 1.025. If it is less than 1.006, the aromatic dihydric phenol used remains unreacted, and the desired molecular weight may not be obtained, which is not preferable. On the other hand, if it exceeds 1.025, only a resin having a large amount of carboxylic acid halide terminals may be obtained.

  Aromatic dicarboxylic acid halides may be directly solid or mixed with a solution dissolved in an organic solvent, but as a more preferred form, they are mixed as a solution dissolved in an organic solvent.

  As the organic solvent to be used, any inert organic solvent that dissolves the reaction product such as aromatic dicarboxylic acid halide and arylate oligomer, polyarylate as a raw material at the reaction temperature but does not substantially dissolve water is used. It is done.

  Typical inert organic solvents include aliphatic hydrocarbons such as hexane and n-heptane, methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, dichloropropane and 1,2-dichloroethylene. Chlorinated aliphatic hydrocarbons, aromatic hydrocarbons such as benzene, toluene and xylene, chlorinated aromatic hydrocarbons such as chlorobenzene, o-dichlorobenzene and chlorotoluene, and other substituted aromatic carbons such as nitrobenzene and acetophenone Hydrogen is included.

  Of these, chlorinated hydrocarbons such as methylene chloride or chlorobenzene are preferably used. These inert solvents can be used alone or as a mixture with other solvents.

  The organic solvent solution of the aromatic dicarboxylic acid halide in the present embodiment is preferably added dropwise, and more preferably added in about 30 minutes to 90 minutes. If it is less than 30 minutes, hydrolysis of the aromatic dicarboxylic acid halide is accelerated, the amount of unreacted aromatic dihydric alcohol increases, and the molecular weight does not increase, which is not preferable. On the other hand, if it exceeds 90 minutes, the molecular weight distribution of the polyarylate obtained is widened, which is not preferable.

  The amount of the organic solvent during the interfacial polymerization is usually such that the polymer concentration in the organic solvent solution is 15% by weight or more at the initial stage of polymerization for 1 hour to 5 hours after the completion of the dropping of the aromatic carboxylic acid halide in the organic solvent solution. It is preferable that the reaction solution is appropriately diluted with an organic solvent during the polymerization so that the polymer concentration in the organic solvent solution is 10% by weight or less.

  As used herein, the term “initial polymerization” means a process of increasing the molecular weight in a state where the polymer concentration in the organic solvent solution is high, and the term “late polymerization” refers to a state in which the polymer concentration in the organic solvent solution is dilute. This means the process of promoting further consumption and decomposition of the terminal end of the residual carboxylic acid halide. Specifically, the initial stage of polymerization means that the polymer concentration in the organic solvent solution is maintained at a high concentration of 15% by weight or more, and quaternary ammonium. The process of increasing the molecular weight of polyarylate using salts is shown. Late polymerization means that the polymer concentration in the organic solvent solution is kept at a dilute state of 10% by weight or less, and residual carboxylic acid halide terminal is used with tertiary amines. The process which promotes further consumption and decomposition | disassembly of is shown. If the polymer concentration is less than 15% by weight in the initial stage of polymerization, the reactivity of the polymer chain extension reaction is lowered and the predetermined molecular weight is not reached. On the other hand, when the concentration is higher than 10% by weight in the latter stage of polymerization, further consumption and decomposition of the residual carboxylic acid halide terminal are not promoted, and the carboxylic acid halide terminal of the polyarylate is not reduced to a predetermined amount, which is not preferable.

  Further, when the polymer concentration is not changed, for example, if the polymer concentration is kept at a high concentration at the beginning of polymerization, the consumption of carboxylic acid halide ends is dull, and the amount of carboxylic acid halide ends in the polyarylate resin is not preferable. On the other hand, if the polymer concentration is kept in a dilute state at the end of polymerization, it is not preferable because the reactivity is lowered and the predetermined molecular weight is not reached.

  As a more preferable form in the present embodiment, dilution adjustment is performed with an organic solvent so that the polymer concentration is 15% by weight to 20% by weight in the initial stage of polymerization and 5% by weight to 10% by weight in the late stage of polymerization.

  The amount of the aqueous alkali solution used during the interfacial polymerization is usually 1.1 to 3.0 in terms of volume ratio in the initial stage of polymerization for several hours after completion of dropping of the organic solvent solution of the carboxylic acid halide with respect to the organic solvent. Since the amount of the organic solvent thereafter changes, it is in the range of 0.5 to 1.0 times in the latter polymerization stage. Furthermore, sodium hydroxide, potassium hydroxide, etc. are mentioned as an alkali used at the time of reaction. At this time, the concentration of the aqueous alkali solution needs to be within a range of 1.1 to 1.4, which is a ratio obtained by dividing the number of moles of alkali components, that is, hydroxide ions, by the number of moles of hydroxyl groups of the aromatic dihydric alcohol. is there. When this ratio is larger than 1.4, hydrolysis of acid halide by hydroxide ions is promoted, which is not preferable. On the other hand, when this ratio is smaller than 1.1, an aromatic dihydric alcohol component having low solubility is not preferable because an undissolved product is generated.

  Furthermore, as a polymerization catalyst used at the time of interfacial polymerization, trimethylamine, triethylamine, tri-n-butylamine, tri-n-propylamine, triisopropylamine, trihexylamine, tridecylamine, N, N-dimethylcyclohexylamine, pyridine, Tertiary amines such as quinoline and dimethylaniline, quaternary ammonium such as trimethylbenzylammonium halide, tetramethylbenzylammonium halide, triethylbenzylammonium halide, tri-n-butylbenzylammonium halide, tetra-n-butylammonium halide Salts, trimethylbenzylphosphonium halide, tetramethylbenzylphosphonium halide, triethylbenzylphosphonium halide, tri-n-butylbenzyl Quaternary phosphonium salts such as sulfonium halide, tetra-n-butylphosphonium halide, triphenylbenzylphosphonium halide, tetraphenylphosphonium halide, 18-crown-6, 18-benzocrown-6, 18-dibenzocrown-6, And crown ethers such as 15-crown-5, and quaternary ammonium salts are used at the initial stage of polymerization for several hours after completion of dropping of the organic solvent solution of carboxylic acid dihalide, and as an auxiliary catalyst at the later stage of polymerization. Tertiary amines are preferably added, and the auxiliary catalyst may be added at the same time as lowering the polymer concentration in the organic solvent solution in the late stage of polymerization, or may be added several hours after the polymer concentration is lowered. good.

  In the present embodiment, it is effective to use a quaternary ammonium salt as a catalyst and a tertiary amine as a cocatalyst in combination. This is because quaternary ammonium salts are effective in increasing molecular weight, and tertiary amines are effective in increasing molecular weight and decomposing carboxylic acid halides. In particular, since tertiary amines have a great effect of decomposing carboxylic acid halides, it is preferable to add the catalyst and the auxiliary catalyst at different timings and to add the quaternary ammonium salt as the catalyst first.

  Further, the addition amount of the catalyst and the auxiliary catalyst is preferably 1.0 to 1.5 mol%, more preferably 1 to 4 mol% of the quaternary ammonium salt as the catalyst with respect to the aromatic dihydric alcohol. .3 mol% or less, more preferably 1.2 mol% or less. The tertiary amine as an auxiliary catalyst is preferably 0.3 to 1.5 mol%, more preferably 1.3 mol% or less, and still more preferably 1%, based on the aromatic dihydric alcohol. .2 mol% or less. When the amount of the catalyst and the auxiliary catalyst exceeds 1.5 mol%, the hydrolysis reaction is promoted, which is not preferable. On the other hand, when the catalyst is less than 1.0 mol%, the molecular weight does not increase, which is not preferable. When the auxiliary catalyst is less than 0.3 mol%, the carboxylic acid halide terminal amount does not decrease, which is not preferable.

  The temperature used for the interfacial polycondensation reaction of the polyarylate is preferably 15 ° C. or higher, and at a temperature higher than 40 ° C., decomposition of the carboxylic acid halide is promoted and, as a result, the molecular weight does not increase. . In particular, 20 ° C to 30 ° C is more preferable. If it is less than 15 ° C., the reactivity of the aromatic dicarboxylic acid halide decreases, and the carboxylic acid halide terminal increases, which is not preferable.

  After completion of interfacial polymerization, the polymerization solution is preferably washed using a conventionally known method such as stationary separation or a centrifugal separator. First, the aqueous phase containing salts and unreacted monomers is separated and removed, and the reaction is stopped and neutralized by adding an acid to the organic solvent phase and washing. The method is used to separate an aqueous phase containing salts and an organic solvent phase in which polyarylate is dissolved. As the acid used at this time, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid and the like are preferable. Furthermore, the organic solvent phase is washed with an alkali to remove unreacted monomers contained in the organic solvent phase, and the salt-containing aqueous phase and polyarylate are again separated using a conventionally known method such as stationary separation and centrifuge. Separated into dissolved organic solvent phase. Examples of the alkali used at this time include sodium hydroxide and potassium hydroxide. The organic solvent phase in which the separated polyarylate is dissolved is neutralized by pickling, and then the organic solvent phase in which the separated polyarylate is dissolved is washed with water several times to remove residual salts. preferable. The water used at this time is preferably demineralized water.

In the washing step in the present embodiment, the ratio of the organic solvent phase and the aqueous phase is preferably 1.0 to 1.5 in volume ratio. If this is less than 1.0, the aqueous phase becomes excessive and the hydrolysis reaction of the polyarylate chain is promoted, which is not preferable. On the other hand, when the ratio exceeds 1.5, the washing becomes insufficient, and unreacted monomers and salts remain in the polyarylate resin.
Further, the washing time is preferably 30 minutes or more from the viewpoint of detergency. More preferably, it is performed for 30 minutes to 60 minutes.

  Furthermore, it is preferable to use a centrifuge for separation after washing, but it may be stationary separation. When static separation is used, the separation time depends on the liquid separation between the organic solvent phase in which polyarylate is dissolved and the aqueous phase, but it is efficient to leave the organic solvent phase at least as long as the washing time. It is preferable to obtain

  Various methods can be selected to isolate and purify the polyarylate from the organic solvent solution of the polyarylate isolated by the above method. For example, there are a method for obtaining a polyarylate powder by evaporating the organic solvent while keeping the organic solvent solution of polyarylate in a suspended state in water, and the like.

  The viscosity average molecular weight of the polyarylate resin comprising the repeating unit having the structure represented by the general formula (1) in the present embodiment is preferably 10,000 to 300,000, more preferably 15,000 to 100,000. More preferably, it is 20,000 or more and 50,000 or less. If the viscosity average molecular weight is less than 10,000, the mechanical strength of the resin is lowered, which is not practical, and if it is 300,000 or more, it is difficult to apply an appropriate film thickness.

  In addition, the polyarylate resin in the present embodiment can be mixed with other resins and used for an electrophotographic photosensitive member. Other resins mixed here include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resins, Various thermosetting resins are exemplified.

<Electrophotographic photoreceptor>
The polyarylate resin to which the above-described embodiment is applied is used for an electrophotographic photosensitive member, and is used as a binder resin in a photosensitive layer provided on a conductive support of the photosensitive member. As the conductive support, for example, a metal material such as aluminum, aluminum alloy, stainless steel, copper, or nickel, or a resin material or aluminum imparted with conductivity by adding conductive powder such as metal, carbon, or tin oxide. A resin, glass, paper, or the like obtained by depositing or coating a conductive material such as nickel or ITO (indium oxide tin oxide alloy) on the surface is mainly used. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be coated on a conductive support made of a metal material for controlling conductivity, surface property, etc., or for covering defects.

  When a metal material such as an aluminum alloy is used as the conductive support, it may be used after anodizing, chemical conversion coating or the like. When the anodizing treatment is performed, it is desirable to perform a sealing treatment by a known method. The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support.

  An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used. Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. Only one type of particle may be used, or a plurality of types of particles may be mixed. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used, and a plurality of crystal states may be included.

  In addition, various particle sizes of the metal oxide particles can be used. Among them, from the viewpoint of characteristics and liquid stability, the average temporary particle size is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more. 50 nm or less. The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As binder resin used for the undercoat layer, phenoxy, epoxy, polyvinyl pyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are used alone or in a cured form with a curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coating properties.

  The addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10% by weight to 500% by weight from the viewpoint of the stability of the dispersion and the coating property. The thickness of the undercoat layer can be arbitrarily selected, but is preferably 0.1 μm to 20 μm from the viewpoint of photoreceptor characteristics and applicability. Moreover, you may add a well-known antioxidant etc. to an undercoat layer.

Specific configurations of the photosensitive layer in the present embodiment include the following configurations (1) to (3) as examples of basic shapes. That is,
(1) A laminate type photoreceptor in which a charge generation layer mainly composed of a charge generation material, a charge transport material and a charge transport layer mainly composed of a binder resin are laminated in this order on a conductive support.
(2) A reverse two-layer type photoreceptor in which a charge transport layer mainly composed of a charge transport material and a binder resin and a charge generation layer composed mainly of a charge generation material are laminated in this order on a conductive support.
(3) A dispersion type photoreceptor in which a charge generation material is dispersed in a layer containing a charge transport material and a binder resin on a conductive support.

  In the case of a multilayer photoreceptor, charge generation materials used for the charge generation layer include, for example, selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, indigo pigments, Various photoconductive materials such as organic pigments such as perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments can be used, and organic pigments, phthalocyanine pigments, and azo pigments are particularly preferable. These fine particles are, for example, polyester resin, polyvinyl acetate, polyacrylic ester, polymethacrylic ester, polyester, polycarbonate, polyvinyl acetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose. Used in a form bound with various binder resins such as ether. In this case, the usage ratio is from 30 parts by weight to 500 parts by weight with respect to 100 parts by weight of the binder resin, and the film thickness is usually 0.1 μm to 1 μm, preferably 0.15 μm to 0.6 μm. is there.

  When a phthalocyanine compound is used as the charge generation material, specifically, a metal such as metal-free phthalocyanine copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or a coordination thereof such as an oxide or a halide. Phthalocyanines are used. Examples of the ligand to a metal atom having 3 or more valences include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. In particular, highly sensitive X-type, τ-type metal-free phthalocyanine, A-type, B-type, D-type titanyl phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and the like are suitable. Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. It is shown by Heller et al. As phase I and phase II, respectively (Zeit. Kristallogr. 159, (1982), 173), and type A is known as a stable type. The D-type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays. As the phthalocyanine compound, only a single compound may be used, or several mixed states may be used. As the mixed state that can be placed in the phthalocyanine compound or crystal state here, the respective constituent elements may be mixed and used later, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be generated. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known.

  These charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone; cyano compounds such as tetracyanoquinodimethane; electron-withdrawing materials such as quinones such as diphenoquinone; carbazole derivatives, indoles Derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, oxadiazole derivatives, pyralizone derivatives, thiadiazole derivatives, etc .; aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds, these compounds And an electron donating substance such as a polymer having a group composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded are preferable, and those in which a plurality of aromatic amine derivatives, stilbene derivatives, and butadiene derivatives are bonded. Particularly preferred.

  These charge transport materials may be used alone or in combination. The charge transport layer is formed in such a form that these charge transport materials are bound to the binder resin. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituent components or composition ratios. The ratio of the binder resin to the charge transport material in the charge transport layer is usually in the range of 30 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. Used in. The film thickness is generally 5 μm to 50 μm, preferably 10 μm to 45 μm. It should be noted that the charge transport layer has well-known plasticizers, antioxidants, ultraviolet absorbers, and electron withdrawing properties in order to improve film forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. You may contain additives, such as a compound and a leveling agent.

  Examples of the electron-withdrawing compound include quinones such as chloranil, 2,3-dichloro-1,4-naphthoquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, and phenanthrenequinone. Aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 2,4,7-trinitrofluorenone, 3,3 ′, 5,5′-tetranitrobenzophenone, etc. Ketones; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; tetracyanoethylene, terephthalalmalononitrile, 9-anthrylmethylidenemalononitrile, 4-nitrobenzalmalononitrile, 4- (p- Nitrobenzoyloxy) benzalmalononitrile, etc. Ano compounds; phthalides such as 3-benzalphthalide, 3- (α-cyano-p-nitrobenzal) phthalide, 3- (α-cyano-p-nitrobenzal) -4,5,6,7-tetrachlorophthalide, etc. An electron withdrawing compound is mentioned.

  Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. In the case of a dispersion-type photosensitive layer, the above-described charge generating material is dispersed in the charge transport medium having the above-described blending ratio. In this case, the particle size of the charge generating material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is used in the range of 50% by weight, more preferably in the range of 1% by weight to 20% by weight.

  The film thickness of the photosensitive layer is usually 5 μm to 50 μm, more preferably 10 μm to 45 μm. Also in this case, known plasticizers for improving film formability, flexibility, mechanical strength, additives for suppressing residual potential, dispersion aids for improving dispersion stability, coating Leveling agents for improving the properties, surfactants such as silicone oil, fluorine oil and other additives may be added.

  A protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge product generated from a charger or the like. Further, for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, the surface layer may contain a fluorine-based resin, a silicone resin, or the like. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.

  Each layer constituting these photoreceptors is formed on the support by dip coating, spray coating, nozzle coating, bar coating, roll coating, blade coating or the like. As a method for forming each layer, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance contained in a layer in a solvent is applicable.

  An electrophotographic apparatus such as a copying machine or a printer using an electrophotographic photosensitive member to which the present embodiment is applied includes at least charging, exposure, development, and transfer processes. Either may be used. As a charging method (charger), for example, corotron or scorotron charging using corona discharge, contact charging using a conductive roller, brush, film, or the like may be used. Of these, scorotron charging is often used in charging methods using corona discharge in order to keep the dark potential constant. As a developing method, a general method of developing by bringing a magnetic or non-magnetic one-component developer or two-component developer into contact or non-contact is used. As a transfer method, any method using a corona discharge, a method using a transfer roller or a transfer belt may be used. The transfer may be performed directly on paper, an OHP film, or the like, or may be transferred to an intermediate transfer body (belt shape or drum shape) and then transferred onto paper or an OHP film.

  Usually, after the transfer, a fixing process for fixing the developer onto paper or the like is used, and commonly used thermal fixing, pressure fixing, or the like can be used as the fixing means. In addition to these processes, processes such as commonly used cleaning and static elimination may be included.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.
<Quantification of carboxylic acid halide terminal amount of polyarylate>
About 1 g of polyarylate was precisely weighed, and 20 mL of methylene chloride was added and dissolved. To this was added 2 mL of a 1% by weight methylene chloride solution of 4- (p-nitrobenzyl) pyridine (Wako Pure Chemicals, reagent special grade) to develop a color, and 440 nm using a spectrophotometer (manufactured by Shimadzu Corporation, UV-1600). Absorbance at the wavelength of was measured. Separately, the extinction coefficient was obtained using phenylchloroformate or a methylene chloride solution of the carboxylic acid dihalide, and the terminal amount of the carboxylic acid halide in the sample was quantified. The lower limit of quantification was 0.2 ppm vs. solid f content in terms of chlorine content.
In this measurement method, free halogen atoms present in the polyarylate resin are not observed. Therefore, the value obtained by the measurement is purely for the carboxylic acid halide terminal present in the polyarylate.

<Viscosity average molecular weight>
Polyarylate resin was dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Next, using a Ubbelohde capillary viscometer, the flow time t ₀ of the solvent (dichloromethane) and the flow time t of the sample solution were measured in a constant temperature water bath set to 20.0 ° C. And the viscosity average molecular weight Mv was computed according to the following formula | equation.
a = (0.28 × η _sp ) +1
b = 10 × (η _sp / C)
η _sp = (t / t ₀ ) −1
C = 6.00 (g / L)
η = (b / a)
Mv = 51400 × [η] exp 1.205

<Manufacture of polyarylate resin>
Example 1
Using a 1.5-liter reaction vessel A with a baffle plate equipped with a two-stage paddle type stirring device and a temperature control device, it may be abbreviated as bis (3,5-dimethyl-4-hydroxyphenyl) methane (hereinafter, TmBPF). 45.83 g (0.179 mol) and bis (4-hydroxyphenyl) methane (hereinafter sometimes abbreviated as p, p′-BPF), (2-hydroxyphenyl) (4-hydroxyphenyl) A mixture of methane (hereinafter sometimes abbreviated as o, p′-BPF) and bis (2-hydroxyphenyl) methane (hereinafter sometimes abbreviated as o, o′-BPF) [manufactured by Honshu Chemical Co., Ltd. BPF-D; p, p′-BPF: o, p′-BPF: o, o′-BPF = about 35:48:17] 15.34 g (0.0767 mol) and 25% aqueous sodium hydroxide solution 09.7g After (equivalent to 1.3 times the total phenolic hydroxyl groups) was dissolved in demineralized water 835.5G, a phase transfer catalyst benzyl triethyl ammonium chloride (hereinafter, sometimes abbreviated as BnEt ₃ NCl ) 0.692 g (0.003 mol), 2,3,6-trimethylphenol (hereinafter sometimes abbreviated as 2,3,6-TMP) as a terminal terminator 2.08 g (0.0153 mol) Were dissolved in order.

  Also, using another 1 liter container B, 54.59 g (0.2689 mol) of terephthalic acid dichloride (hereinafter sometimes abbreviated as TPC) was dissolved in 506 g of methylene chloride, and the solution was fed. Transfer to a 0.5 liter weighing tank equipped with a pump.

  While maintaining the reaction vessel A at 20 ° C., stirring the alkaline aqueous solution, the methylene chloride solution was added over 30 minutes. When the measuring tank was emptied, 116 g of methylene chloride was added to the measuring tank. The adhered TPC was transferred to the reaction vessel A. After carrying out the polymerization reaction for 1 hour under stirring, 964 g of methylene chloride was added to dilute the reaction solution, and 0.154 g (0.00152 mol) of triethylamine (hereinafter sometimes abbreviated as TEA) as a phase transfer auxiliary catalyst. ) Added.

Thereafter, the polymerization reaction was carried out for 5 hours under stirring, the stirring was stopped, the mixture was left to stand for 1 hour, the methylene chloride phase was taken out, and the methylene chloride phase was mixed with 0.85 liter of 0.1N hydrochloric acid aqueous solution for 30 minutes. The reaction was stopped by stirring to remove the catalyst.
After stopping the reaction, the methylene chloride layer containing the produced polyarylate resin was separated by performing stationary separation for 30 minutes.

  In order to wash the methylene chloride phase containing the produced polyarylate resin, 0.8N of 0.1N sodium hydroxide aqueous solution, 0.1N hydrochloric acid aqueous solution and demineralized water were used for each washing step as follows. It was. First, a methylene chloride phase containing a polyarylate resin was added under stirring with an aqueous sodium hydroxide solution, stirred for 30 minutes, and then allowed to stand for 1 hour to separate the methylene chloride phase. Next, the methylene chloride phase was added under stirring with an aqueous hydrochloric acid solution and stirred for 30 minutes, and then allowed to stand for 1 hour to separate the methylene chloride phase. Further, the methylene chloride phase was added under stirring with demineralized water and stirred for 30 minutes, and then allowed to stand for 30 minutes to separate the methylene chloride phase. Finally, the methylene chloride phase was once again put under stirring with demineralized water (newly replaced), stirred for 30 minutes, and then allowed to stand for 2 hours to separate the methylene chloride phase.

  The methylene chloride phase after washing is spread on a vat, heated on a hot plate (140 ° C) to remove methylene chloride, and the resulting polymer is well dried in a draft dryer (120 ° C) (about 1 hour) Went. The physical properties of the obtained polymer are shown in Table 1. The polyarylate resin thus obtained is designated as C-1.

Example 2
A polymer was obtained in the same manner as in Example 1, except that the amount of TEA, the addition time, and the amount of 2,3,6-TMP were changed as shown in Table 1. The polyarylate resin thus obtained is designated C-2.

Example 3
A polyarylate resin C-3 was obtained in the same manner as in Example 1 except that the amount of 2,3,6-TMP added was changed as shown in Table 1.

Example 4
A polyarylate resin C-4 was obtained in the same manner as in Example 1 except that the amount of TEA, the addition time, and the amount of 2,3,6-TMP were changed as shown in Table 1. However, in Example 4, instead of the reaction vessel A, a 150-liter reaction vessel C with a baffle plate equipped with a two-stage paddle type agitation device and a temperature adjustment device was used, and a 50-liter device equipped with an agitation device instead of the vessel B. A liter reaction vessel D was obtained by hot water granulation using a 10 liter measuring vessel as a measuring vessel.

Comparative Example 1
Polyarylate resin C-5 was obtained in the same manner as in Example 1 except that TEA was not added, and the addition amount of 2,3,6-TMP and the polymerization time were changed as shown in Table 1.

Comparative Example 2
A polyarylate resin C-6 was obtained in the same manner as in Example 1 except that the temperature of the reaction vessel A was 10 ° C.

Comparative Example 3
Polyarylate resin C-7 was obtained in the same manner as in Example 1 except that the amount of TEA added and the polymerization time were changed as shown in Table 1 and the polymerization solution was not diluted with MC.

Comparative Example 4
A polyarylate resin C-8 was obtained in the same manner as in Example 1 except that the addition amounts of TPC, BnEt3NCl, and TEA were changed as shown in Table 1.

Comparative Example 5
A polyarylate resin C-9 was obtained in the same manner as in Comparative Example 3 except that the amount of TEA added was changed as shown in Table 1.

Comparative Example 6
Amount of TPC and TEA, and the polymerization time was changed as described in Table 1, to obtain a polyarylate resin C-10 in the same manner as the actual Example 1.
Table 1 shows the polymerization conditions and the like of the polyarylate resin C-1 to polyarylate resin C-10.

*: Molar ratio of aromatic dihydric alcohol component #: Elapsed time from the start of polymerization (at the end of TPC / MC solution addition)

<Manufacture of electrophotographic photoreceptor>
10 parts by weight of A-type oxytitanium phthalocyanine was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2 and pulverized with a sand grind mill.

  Further, 5% of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: Denkabutyral # 6000C) 5% 1,2-dimethoxyethane solution and phenoxy resin (trade name PKHH, trade name: PKHH) -A binder solution was prepared by mixing 100 parts of a dimethoxyethane solution.

  100 parts by weight of the binder solution and an appropriate amount of 1,2-dimethoxyethane were added to 160 parts by weight of the previously prepared pigment dispersion to prepare a dispersion having a solid component concentration of 4.0%. The dispersion thus obtained was applied onto a polyethylene terephthalate film having aluminum deposited on the surface so as to have a film thickness of 0.4 μm to provide a charge generation layer. Next, on this film, 50 parts by weight of the following hole transporting compound [1],

And 100 parts by weight of a polyarylate resin, 8 parts by weight of an antioxidant (Irganox 1076), and 0.03 part by weight of silicone oil as a leveling agent, a mixed solvent of tetrahydrofuran and toluene (80% by weight of tetrahydrofuran, 20% by weight of toluene) 640 A solution dissolved in parts by weight was applied, dried at 125 ° C. for 20 minutes, and a charge transport layer was provided so that the film thickness after drying was 20 μm. At this time, the solubility of the polyarylate resin in the tetrahydrofuran and toluene mixed solvent was good. Further, this coating solution did not show any change such as solidification after standing at room temperature for 1 hour.
Each of the obtained photoreceptors was evaluated for the following electrical characteristics.

Using an electrophotographic characteristic evaluation apparatus (in accordance with electrophotographic technology basics and applications, edited by the Electrophotographic Society, Corona, pages 404-405) prepared according to the electrophotographic society measurement standard, the photoconductor is made into an aluminum drum. Paste it into a cylindrical shape, establish electrical continuity between the aluminum drum and the aluminum substrate of the photoconductor, rotate the drum at a fixed number of revolutions, and conduct an electrical property evaluation test by a cycle of charging, exposure, potential measurement, and static elimination It was. At that time, the initial surface potential was set to −700 V, the exposure was performed at 780 nm, the charge removal was performed at 660 nm, and the surface potential (VL) when 780 nm light was irradiated at 2.4 μJ / cm ² was measured. In the VL measurement, the time required for the exposure-potential measurement was set to 139 ms. The measurement environment was a temperature of 25 ° C., a relative humidity of 50% (VL: NN), and a temperature of 5 ° C. and a relative humidity of 10% (VL: LL). The smaller the absolute value of the surface potential (VL), the better the response. Further, when measuring the surface potential (VL), the grid voltage (Vg) necessary for charging the surface potential of the photoreceptor to -700 V was measured. The Vg measurement was performed at a temperature of 25 ° C., a relative humidity of 50% (Vg: NN), and a temperature of 5 ° C. and a relative humidity of 10% (Vg: LL) as in the VL measurement. The smaller the absolute value of the grid voltage (Vg), the easier it is to charge. The results are shown in Table 2.

  From the results shown in Table 2, the photoreceptor according to the present invention can be charged to -700 V with a lower grid voltage, and has excellent chargeability.

Claims (4)

In an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, the photosensitive layer containing a polyarylate resin,
The polyarylate resin is
A polyarylate resin obtained by an interfacial polycondensation reaction of an aromatic dicarboxylic acid component and an aromatic dihydric alcohol component, wherein the polyarylate resin has a viscosity average molecular weight of 15,000 or more and 100,000 or less, and the polyarylate 1. An electrophotographic photoreceptor comprising a polyarylate resin having a carboxylic acid halide terminal represented by the following general formula (1) contained in a resin in a weight ratio of 10 ppm or less with respect to the polyarylate resin.

[In General Formula (1), PAR represents a polyarylate chain, and X represents a halogen atom. ]   The electrophotographic photosensitive member according to claim 1, wherein the halogen atom at the carboxylic acid halide terminal in the polyarylate resin is a chlorine atom. The polyarylate resin has a repeating unit represented by the following general formula (2) and uses one kind of aromatic dicarboxylic acid halide and two or more kinds of dihydric phenol components. The electrophotographic photosensitive member according to claim 2.

[In General Formula (2), R _{1 to} R ₈ each independently represent a hydrogen atom or any hydrocarbon group having 1 or more carbon atoms, and X represents a single bond, an oxygen bond, a sulfur bond, an alkylene group, or an alkylidene. Selected from the group consisting of a group, a phenylalkylidene group and a cyclic hydrocarbon group, and Y is selected from the group consisting of a phenylene group, a biphenylene group, a naphthylene group, an aliphatic hydrocarbon group and a cyclic hydrocarbon group. ] Terephthalic acid dichloride is used as the aromatic dicarboxylic acid component of the polyarylate resin, and a dihydric phenol represented by the following structural formula (A) and the following general formula (3) is used as the dihydric phenol component. The electrophotographic photosensitive member according to claim 3.

(General formula (3) is one or a mixture selected from the group represented by the following structural formula (B), structural formula (C), and structural formula (D).)