JP2003270806A - Electrophotographic photoreceptor, coating liquid therefor, carbonate oligomer composition, method for producing the composition and method for producing polycarbonate resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having controlled molecular terminals and molecular weight and excellent in electrical properties, and to provide a coating liquid for electrophotography used therefor, a polycarbonate resin and an oligomer composition. <P>SOLUTION: In the electrophotographic photoreceptor having at least a photosensitive layer on an electrically conductive substrate, the binder resin of the photosensitive layer is a polycarbonate resin which satisfies the following conditions a)-d); a) the resin is obtained by condensation-polymerizing at least one aromatic diol and a carbonate forming compound in the presence of monophenol; b) the amount of molecular terminal OH groups is ≤20 μeq/g, c) the proportion of the amount of molecular terminal monophenol groups to the amount of all molecular terminal groups is ≥80% and d) the viscosity average molecular weight is 5,000-100,000. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor and a method for producing a polycarbonate resin for an electrophotographic photoreceptor.

[0002]

2. Description of the Related Art The electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers in recent years because of its ability to obtain instant images and high quality images. Photoreceptors, which are the core of electrophotographic technology, have recently been formed as pollution-free inorganic photoconductors such as selenium, arsenic-selenium alloy, cadmium sulfide, and zinc oxide. A photoreceptor using an organic photoconductive material, which has advantages such as easy and easy manufacture, has been developed.

Among organic photoconductors, a so-called laminated type photoconductor in which a charge generation layer and a charge transport layer are laminated has been devised and is the mainstream of research. The multi-layered photoconductor is a high-sensitivity photoconductor obtained by combining a highly efficient charge-generating substance and a charge-transporting substance, and a photoconductor having a wide selection range of materials and high safety, Further, since the coating productivity is high and the cost is comparatively advantageous, the possibility of becoming the mainstream of the photoreceptor is high and the coating has been earnestly developed.

Usually, the charge transport layer is composed of a solid solution of a binder resin and a charge transport material, and various binder resins have been developed in order to obtain good electric characteristics. So far, as binder resins for charge transport layers, vinyl polymers such as polymethacrylate, polystyrene and polyvinyl chloride, and their copolymers, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy and silicone resins and thermosetting. Resin is used. Above all, various polycarbonate resins having excellent performance as binder resins have been developed and put into practical use.

For example, bisphenol P type polycarbonate (for example, refer to Patent Document 1), bisphenol Z type polycarbonate (for example, refer to Patent Document 2), copolymer type polycarbonate of bisphenol P and bisphenol A (for example, refer to Patent Document 3), Various polycarbonate resins such as a polycarbonate copolymer having a bis (4-hydroxyphenyl) ketone type structure (see, for example, Patent Document 4) are disclosed as binder resins.

In the process of forming the charge transport layer, the electrotransport agent and the binder resin are dissolved in a mixed solvent to prepare a coating solution having a certain concentration and viscosity, and then a certain film is formed on the drum. A thick coating method is used. In this case, if the concentration and viscosity of the coating liquid change, the coating conditions and drying conditions must be changed each time in order to obtain a constant film thickness.
As a result, there is a possibility that fatal defects may occur in OPC due to coating unevenness and the like, and it is important to control the viscosity at the time of manufacturing the coating liquid, that is, the molecular weight of the binder resin.

However, the polycarbonate resin produced by the conventional technique may have a large error from the target molecular weight, and it has been difficult to obtain a polycarbonate resin having a controlled molecular weight with good reproducibility. For this reason, it is necessary to blend polycarbonate resins of different molecular weights at the stage of manufacturing the coating liquid and adjust them so that the concentration and viscosity fall within the specifications, and the labor required for this and the production of new resin due to the deviation of the molecular weight. However, there was a problem that the cost was significantly increased. Further, even if a polycarbonate resin having the same molecular weight is obtained, the molecular terminals are often different, and as a result, when used as an electrophotographic photoreceptor, there is a problem that the electrical characteristics deteriorate. It is described that a polycarbonate resin having a molecular terminal OH group concentration of 100 ppm or less is used as a binder resin in order to improve electric characteristics (see, for example, Patent Document 5). However, a molecular terminal and a polycarbonate resin having a controlled molecular weight cannot be obtained only by reducing the concentration of the OH group at the molecular terminal. Further, recently, the conditions for use in printers, copying machines, etc. have become more severe, and the electrical characteristics as an electrophotographic photoreceptor may be insufficient even if the above-mentioned polycarbonate resin having a reduced concentration of OH groups on the molecular terminals is used. .

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic photosensitive member having controlled molecular ends and molecular weights and excellent electrical characteristics. An object of the present invention is to provide an electrophotographic photosensitive member coating liquid used for an electrophotographic photosensitive member having excellent electric characteristics. Another object of the present invention is to
It is an object of the present invention to provide a polycarbonate resin preferably used as a binder resin for a photosensitive layer of an electrophotographic photoreceptor and a method for producing the same. Another object of the present invention is to provide an oligomer composition as a precursor for producing a polycarbonate resin and a method for producing the same.

[0009]

[Patent Document 1] Japanese Patent Laid-Open No. 50-98332

[Patent Document 2] Japanese Patent Laid-Open No. 59-71057

[Patent Document 3] Japanese Patent Laid-Open No. 59-184251

[Patent Document 4] JP-A-5-21478

[Patent Document 5] JP-A-4-52654

[0010]

As a result of intensive studies to solve the above problems, the present inventors have found that the terminal group state of the binder resin is related to the electrical characteristics. In addition, it is possible to reproducibly obtain a polycarbonate resin in which end groups and molecular weights are controlled by adding monophenols, which are molecular weight regulators, immediately after consumption of the carbonate-forming compound during molecular weight extension and by polycondensation in the presence of alkali. Heading The invention has been reached. That is, the gist of the present invention is an electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is a polycarbonate resin satisfying the following a) to d). It exists in the body. A) It is obtained by polycondensation of at least one aromatic diol and a carbonate-forming compound in the presence of monophenols, and b) the amount of OH groups at the molecular terminals is 20 μeq / g or less, and c) In addition, the ratio of the amount of monophenols at the molecular end to the total amount of terminal ends of the molecule is 90% or more, and d) the viscosity average molecular weight is 5,000 to 100,000.

Another subject matter of the present invention lies in a coating liquid for an electrophotographic photoreceptor containing at least an organic solvent, a charge transfer material, and a polycarbonate resin satisfying the following a) to d). A) It is obtained by polycondensation of at least one aromatic diol and a carbonate-forming compound in the presence of monophenols, and b) the amount of OH groups at the molecular terminals is 20 μeq / g or less, and c) In addition, the ratio of the amount of monophenols at the molecular end to the total amount of terminal ends of the molecule is 90% or more, and d) the viscosity average molecular weight is 5,000 to 100,000.

Another object of the present invention is to obtain a viscosity average obtained by reacting at least one aromatic diol with a carbonate-forming compound in the presence of a monophenol represented by the general formula Ar-OH. Molecular weight 500-10,000
The ratio of unreacted monophenols to charged monophenols in the oligomer oligomer composition is 50% or less, and the content of the compound represented by the following general formula (1) is 0. The carbonate oligomer composition is characterized by being 0.005% by weight or less.

[0013]

[Chemical 4]

(However, Ar represents an aromatic ring residue which may be substituted.)

Another aspect of the present invention is a method for producing a carbonate oligomer composition having a viscosity average molecular weight of 500 to 10,000 by reacting an aromatic diol with a carbonate-forming compound in the presence of a monophenol. , The reaction between the aromatic diols and the carbonate-forming compound proceeds, and the concentration of the carbonate-forming compound is 0.00
A method for producing a carbonate oligomer composition is characterized by mixing monophenols after the amount becomes 1% by weight or less. Another subject matter of the present invention lies in a polycarbonate resin having a viscosity average molecular weight of 5,000 to 100,000 obtained by polycondensation of the carbonate oligomer composition in the presence of an alkali.

Another object of the present invention is to react an aromatic diol with a carbonate-forming compound so that the concentration of the carbonate-forming compound is 0.001% by weight or less, and then mix the monophenols. To obtain a carbonate oligomer composition having an average viscosity molecular weight of 500 to 10,000 and a ratio of unreacted monophenols to charged monophenols of 50% or less, and then polycondensing the carbonate oligomer composition in the presence of an alkali. And a method for producing a polycarbonate resin having a step of obtaining a polycarbonate resin having a viscosity average molecular weight of 5,000 to 100,000.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The polycarbonate resin is obtained by reacting at least one aromatic diol with a carbonate-forming compound, but in the present invention, it is preferable to react in the presence of monophenols. The obtained polycarbonate resin is characterized in that the amount of OH groups at the molecular ends is 20 μeq / g or less, and the ratio of the amount of monophenols at the molecular ends to the total amount of end groups of the molecule is 90% or more. There is.

The carbonate-forming compound used as a raw material is a compound capable of reacting with an aromatic diol to form a carbonate bond, and examples thereof include phosgene and carbonic acid esters such as dimethyl carbonate and diphenyl carbonate. Used. Of these, phosgene is preferred. The aromatic diol used as the other raw material is represented by the general formula HO-Z-OH, where Z is one or more aromatic nuclei, and hydrogen bonded to the carbon of the nuclei. Can be substituted with a halogen atom such as chlorine or bromine, or a substituent such as an aliphatic group or an alicyclic group. The plurality of aromatic nuclei can also have different substituents. Further, the plurality of aromatic nuclei may be bonded by a cross-linking group. The bridging group includes aliphatic groups, cycloaliphatic groups, heteroatoms or combinations thereof.

Specifically, hydroquinone, resorcin,
Biphenol, bis (hydroxyphenyl) alkane,
Bis (hydroxyphenyl) cycloalkane, bis (hydroxyphenyl) sulfide, bis (hydroxyphenyl) ether, bis (hydroxyphenyl) ketone,
Included are bis (hydroxyphenyl) sulfones, bis (hydroxyphenyl) sulfoxides, bis (hydroxyphenyl) dialkylbenzenes, and derivatives thereof having alkyl or halogen substituents in the nucleus. Of course, it is also possible to use two or more of these aromatic diols in combination.

Among these, preferable aromatic diol compounds are represented by the following general formula (3).

[0021]

[Chemical 5]

Or a single bond, R ¹ and R ^{2 each} represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group which may be substituted, or a halogenated alkyl group;
Represents a substituted or unsubstituted carbocycle of 4 to 20, and Y ¹ to Y ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group which may be substituted, Alternatively, it represents a halogenated alkyl group. )

Particularly preferred aromatic diols include 2,2
-Bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z), And 1,1-bis (4-hydroxyphenyl)-
Includes 3,3,5-trimethylcyclohexane.

The monophenols represented by the general formula Ar--OH used as a molecular weight regulator in the present invention include various phenols such as ordinary phenol, pt-butylphenol and p-cresol. Alkylphenols having 1 to 20 carbon atoms such as, and p
-Halogenated phenols such as chlorophenol and 2,4,6-tribromophenol are included. Among them, phenol, p-isopropylphenol, p-
Phenols such as dodecylphenol and p-t-butylphenol in which para groups are substituted with an alkyl group having 1 to 20 carbon atoms are more preferable. The amount of the monophenols used varies depending on the molecular weight of the desired condensate, but it is usually used in an amount of 0.5 to 10% by weight based on the starting aromatic diol. In addition, Ar represents an aromatic ring residue which may be substituted, but as a substituent, a hydroxyl group or a mercapto group which reacts with a carbonate-forming compound of a substrate or a biphenol in order to have a function as a molecular weight regulator. , Amino groups, etc. are excluded. The substituent on the aromatic ring is not particularly limited as long as it is other than these reactive substituents.

The carbonate oligomer composition of the present invention is a carbonate oligomer composition having a viscosity average molecular weight of 500 to 10,000 obtained by reacting an aromatic diol and a carbonate-forming compound in the presence of monophenols. The composition as referred to herein includes, in addition to the carbonate oligomer obtained by the reaction, by-products generated by the reaction and slightly remaining raw materials.

In the carbonate oligomer composition of the present invention, the ratio of unreacted monophenols to the charged monophenols in the oligomer composition is 50% or less, and the compound represented by the following general formula (1) It is essential that the content of is 0.005% by weight or less. The compound represented by the general formula (1) is a compound formed by reacting the hydroxyl group terminal of the monophenol represented by the general formula Ar-OH with a carbonate-forming compound such as phosgene,
For example, when pt-butylphenol is used as the monophenol, the low molecular weight compound is a compound represented by the following formula (5). (Hereafter, this compound will be referred to as "PTB
It may be abbreviated as "PC". )

[0027]

[Chemical 6]

(However, Ar represents an optionally substituted aromatic ring residue.)

[0029]

[Chemical 7]

(In the formula, t-Bu is a tertiary butyl group, -P
h- represents a phenylene group. )

The content of the compound represented by the general formula (1) is preferably less than 0.003% by weight, more preferably less than 0.001% by weight. Within the above range, for example, when the raw material aromatic diol and the carbonate-forming compound are reacted with monophenols as a molecular weight modifier to obtain an oligomer composition, the monophenols are immediately after consumption of the carbonate-forming compound, Specifically, it can be dealt with by mixing the monophenols after the concentration of the carbonate-forming compound becomes 0.001% by weight or less. Further, the amount of unreacted monophenol present in the oligomer composition is 50% or less, preferably 30% or less, and particularly preferably 10% or less with respect to the monophenol used in the reaction.

In order to adjust the concentration of monophenol in the oligomer composition to the above range, monophenol is mixed in the middle of the molecular elongation of the oligomer composition. Here, the concentration of the carbonate-forming compound means that the total amount of the aromatic diol compound which is a raw material, the carbonate-forming compound and the carbonate oligomer composition which is a product, and the carbonate oligomer composition which is undergoing molecular weight extension is consumed. It means the amount (weight ratio) of the raw material carbonate-forming compound.

When monophenols are added in the coexistence of the carbonate-forming compound, a large amount of condensates of monophenols (diphenyl carbonates) as shown in the general formula (1) are produced, and a polycarbonate resin having a target molecular weight is obtained. It is difficult to obtain, and when it is used as a binder resin for an electrophotographic photoreceptor, the electrical characteristics are deteriorated, which is not preferable. Further, when the addition of monophenols is extremely delayed, the molecular end of the obtained polycarbonate resin has a large amount of OH groups,
As a result, the product has not only a reproducible molecular weight but also a peculiar shoulder on the low molecular weight side of the molecular weight distribution, which is not preferable because it has many adverse effects such as sagging during molding.

The present inventors set the amount of OH groups at the molecular ends to 20 μm.
As a result of studying a method in which the ratio of the amount of monophenol groups at the molecular ends to 90% or more with respect to the total amount of end groups of the molecule is equal to or less than eq / g, surprisingly, immediately after the consumption of the carbonate-forming compound as the molecular weight regulator is completed, From this, it was found that the addition can be achieved before the molecular weight extension starts.

The carbonate oligomer composition obtained from the aromatic diol compound and the carbonate-forming compound has a structural unit represented by the following general formula (2).

[0036]

[Chemical 8]

Or a single bond, R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group which may be substituted, or a halogenated alkyl group;
Represents a substituted or unsubstituted carbocycle of 4 to 20, and Y ¹ to Y ⁸ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group which may be substituted, Alternatively, it represents a halogenated alkyl group. ) In the general formula (2), X is preferably an oxygen atom or a carbon number of 5 to 10.
A cycloalkylidene group of, or —CR ¹ R ² — is 0.
R ¹ and R ² are preferably a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group or a phenyl group, more preferably a hydrogen atom or a methyl group, and Y ¹ to Y ² is preferably a hydrogen atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, an n-propyl group,
It is an isopropyl group, a sec-butyl group, an n-butyl group, an isobutyl group, a tert-butyl group, or a phenyl group, more preferably a methyl group or a phenyl group.

Specific examples of the structural unit represented by the general formula (2) include, for example, [1-1] to [1-12] shown below.
And the like. The polycarbonate copolymer of the present invention is particularly [1-1], [1-2], [1-
3], [1-4], and [1-5] having one or more kinds of structural units are preferable, and further, [1-1] to
Those having two or more kinds of structural units selected from [1-5] are preferable. A particularly preferred structural unit is [1-1]
And [1-2].

[0039]

[Chemical 9]

In the present invention, any branching agent can also be used as the raw material of the carbonate oligomer composition. The branching agent used can be selected from various compounds having three or more functional groups. Suitable branching agents include compounds having three or more phenolic hydroxyl groups, eg 2,4
-Bis (4-hydroxyphenylisopropyl) phenol, 2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol, 2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) ) Propane and 1,4-bis (4,4'-dihydroxytriphenylmethyl) benzene. Further, 2,4-dihydroxybenzoic acid, trimesic acid, and cyanuric chloride, which are compounds having three functional groups, can also be used. Among them, those having three or more phenolic hydroxy groups are preferable. Although the amount of the branching agent used varies depending on the desired degree of branching, it is usually used in an amount of 0.05 to 2 mol% based on the aromatic diol.

The carbonate oligomer composition of the present invention can be usually produced by a method in which a carbonate-forming compound and an aromatic diol are reacted under an interfacial polycondensation condition or a solution polymerization condition. A typical and preferred method is to obtain a carbonate oligomer composition by reacting an aqueous metal salt solution and a carbonate-forming compound in an emulsified state in the presence of an organic solvent.

In the above method, the aromatic diols are
Form an aqueous phase with water and water-soluble metal hydroxides. As the metal hydroxide, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is usually used. In the aqueous phase, aromatic diols react with the above hydroxides to form water-soluble metal salts. In this case, the molar ratio of the aromatic diols to the alkali metal hydroxide in the aqueous phase is 1: 1.8-
1: 3.5 is preferable, and 1: 2.0 to 1: 3.2 is more preferable. A small amount of a reducing agent such as hydrosulfite may be added to the aqueous phase.

As the organic solvent to be used, at the reaction temperature and the reaction pressure, the reaction products such as the carbonate-forming compound, the carbonate oligomer composition and the polycarbonate are dissolved, but the water is not dissolved (meaning that a solution is not formed with water). )) With any inert organic solvent. Typical inert organic solvents include aliphatic hydrocarbons such as hexane and n-heptane, methylene chloride, chloroform,
Chlorinated aliphatic hydrocarbons such as carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, dichloropropane and 1,2-dichloroethylene, benzene,
Included are aromatic hydrocarbons such as toluene and xylene, chlorinated aromatic hydrocarbons such as chlorobenzene, o-dichlorobenzene and chlorotoluene, as well as substituted aromatic hydrocarbons such as nitrobenzene and acetophenone. Among them, chlorinated hydrocarbons such as methylene chloride or chlorobenzene are preferably used. These inert organic solvents can be used alone or as a mixture with other solvents.

The carbonate-forming compound is used in liquid or gaseous form. From the viewpoint of temperature control, the carbonate-forming compound is preferably liquid, and a reaction pressure that can maintain the liquid at the reaction temperature is selected. The preferred amount of the carbonate-forming compound used depends on the reaction conditions, particularly the reaction temperature and the concentration of the aromatic diol metal salt in the aqueous phase, but is the number of moles of the carbonate-forming compound relative to 1 mole of the aromatic diol. It is usually 1-2, preferably 1-1.5. If this ratio is too large, the loss of the carbonate-forming compound will increase and the formula (1)
It is not preferable because the condensation product of the terminating agents as shown in FIG. On the other hand, if it is too small, the CO group is insufficient and appropriate molecular weight extension is not performed, which is not preferable.

In the present invention, when the two-phase interfacial condensation method is adopted, it is particularly preferable that the organic phase and the aqueous phase are brought into contact with each other prior to the contact with the carbonate-forming compound to form an emulsion. In order to form an emulsion, in addition to a stirrer having a normal stirring blade, a homogenizer, a homomixer, a colloid mill, a flow jet mixer, a dynamic mixer such as an ultrasonic emulsifier, and a mixer such as a static mixer. Is preferably used. The emulsion usually has a droplet size of 0.01 to 10 μm and has emulsion stability.

The emulsified state is usually the Weber number or P /
It can be expressed by q (additional power value per unit volume). The Weber number is preferably 10,000 or more, more preferably 20,000 or more, and most preferably 35,
It is more than 000. The upper limit is 1,000,0.
A value of about 00 or less is sufficient. Further, P / q is preferably 200 kg · m / liter or more, more preferably 500 kg · m / liter or more, and most preferably 1,000 kg · m / liter or more.

The contact between the emulsion and the carbonate-forming compound is preferably carried out under mixing conditions weaker than the emulsification conditions in order to suppress the dissolution of phosgene in the organic phase, and the Weber number is less than 10,000. Preferably 5,000
It is less than 0, more preferably less than 2,000. Further, as P / q, less than 200 kg · m / liter,
It is preferably less than 100 kg · m / liter, more preferably less than 50 kg · m / liter. The contact with the carbonate-forming compound can be achieved by introducing the carbonate-forming compound into a tubular reactor or a tank reactor.

The oligomerization reaction can be carried out in the presence of a condensation catalyst. The addition is preferably performed after consuming the carbonate-forming compound, and as the condensation catalyst,
It can be arbitrarily selected from among many condensation polymerization catalysts used in the two-phase interfacial condensation method. Among them, trialkylamine, N-ethylpyrrolidone, N-ethylpiperidine, N-ethylmorpholine, N-isopropylpiperidine and N-isopropylmorpholine are suitable, and triethylamine and N-ethylpiperidine are particularly suitable.

The amount of the condensation catalyst used in the oligomerization reaction is 0.005 to 0.
About 1 mol%, preferably 0.03 to 0.08 mol
%. If it is less than 0.005 mol%, the unreacted monophenols in the oligomer composition exceed 50%, and it is difficult to obtain a polycarbonate resin having a controlled molecular weight even if condensed in this state, which is not preferable. On the other hand, 0.1m
If it exceeds ol%, the amount of unreacted monophenols is 50%
Although it becomes the following, it requires a great deal of labor to extract and remove the catalyst in the washing step after the polycondensation, which is not preferable.

The reaction temperature for obtaining the oligomer composition is
It is preferably 80 ° C or lower, preferably 60 ° C or lower, more preferably 10 ° C to 50 ° C, and the reaction time depends on the reaction temperature, but is usually 0.5 minutes to 10 hours, preferably 1 minute to 2 hours. If the reaction temperature is too high, side reactions cannot be controlled, and the carbonate-forming compound basic unit deteriorates. On the other hand, if it is too low, it is a preferable situation for reaction control, but the refrigeration load increases,
The cost is increased accordingly, which is not preferable.

In the step of obtaining the oligomer composition,
The oligomer concentration in the organic phase may be in the range in which the resulting oligomer composition is soluble, and specifically 10 to 40.
It is about% by weight. The ratio of the organic phase is 0.2 to the alkali metal hydroxide aqueous solution of the aromatic diol, that is, the aqueous phase.
A volume ratio of 1.0 is preferred. The viscosity average molecular weight of the oligomer composition obtained under such condensation conditions is usually about 500 to 10,000, preferably 1,000.
~ 5,000.

The oligomer composition thus obtained is converted into a polymeric polycarbonate resin under polycondensation conditions according to a conventional method. In a preferred embodiment, the dissolved organic phase of the oligomer composition is separated from the aqueous phase, and if necessary, the above-mentioned inert organic solvent is added to adjust the concentration of the oligomer composition. That is, the concentration of the polycarbonate resin in the organic phase obtained by polycondensation is 5 to 3
The amount of solvent is adjusted so as to be 0% by weight. Thereafter, an aqueous phase containing water and an alkali metal hydroxide is newly added, and a condensation catalyst is preferably added to adjust the polycondensation conditions, and the desired polycondensation is completed according to the interfacial polycondensation method. The ratio of the organic phase and the aqueous phase at the time of polycondensation is preferably an organic phase: aqueous phase = 1: 0.2 to 1 in volume ratio.

The amount of nitrogen incorporated into the molecular chain of the polycarbonate resin is preferably 10 ppm or less and the amount of terminal chloroformate groups is preferably 0.1 μeq / g or less. If the amount of nitrogen incorporated in the molecular chain or the amount of terminal chloroformate group increases, the electrical properties tend to deteriorate when used in an electrophotographic photoreceptor or the like. In order to reduce the nitrogen taken up at the molecular end to 10 ppm or less and the terminal chloroformate group amount to 0.1 μeq / g or less, the reaction temperature during the polycondensation of the oligomer composition is preferably 15 ° C. or less, More preferably, the temperature is set to 0 ° C to 10 ° C.

After the completion of polycondensation, until the remaining chloroformate group (CF group) becomes 0.1 μeq / g or less,
Wash with an alkali such as sodium hydroxide. After that, the organic phase is washed until the electrolyte is exhausted, and finally the inert organic solvent is appropriately removed from the organic phase to separate the polycarbonate resin. The viscosity average molecular weight (Mv) of the polycarbonate resin thus obtained is usually about 5,000 to 100,000, preferably 10,000 to 100,000, more preferably 2
It is 50,000 to 50,000. If the viscosity average molecular weight is too low, the mechanical strength of the resin is lowered, which is not practical. If it is too high, the fluidity is poor during injection molding, and molding is difficult. Further, when it is used as a binder resin for an electrophotographic photosensitive member, it is difficult to apply it in an appropriate film thickness when the molecular weight is 100,000 or more.

The polycarbonate resin of the present invention can be used, for example, in an electrophotographic photoreceptor. When the polycarbonate resin is used in the electrophotographic photoreceptor, it is contained in the photosensitive layer provided on the conductive support. As a first example of a specific configuration of the photosensitive layer, a charge generating layer containing a charge generating substance as a main component on a conductive support, a charge transporting layer containing a charge transporting substance and a binder resin as a main component. And a charge transport layer containing a charge transport material and a binder resin as main components, and a charge generating substance as a main component on a conductive support. Inverse two-layer type photoconductor in which the charge generating layer is laminated in this order, and as a third example, the charge generating substance is dispersed in a layer containing a charge transporting substance and a binder resin on a conductive support. An example of the basic shape is a structure such as a dispersion type photoconductor. When the polycarbonate resin of the present invention is used as a binder resin for an electrophotographic photoreceptor, a plurality of polycarbonate resins may be blended and used, or a resin other than the polycarbonate resin may be blended and used. As a result, it is necessary to satisfy the above-mentioned requirements b) to d).

In the case of a laminated type photoreceptor, the polycarbonate resin of the present invention is preferably used as a binder resin for the charge transport layer. Examples of the charge generating substance used in the charge generating layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments,
Various photoconductive materials such as organic pigments such as azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments and benzimidazole pigments can be used, and organic pigments, particularly phthalocyanine pigments and azo pigments are preferable.

These fine particles are usually made of polyester resin, polyvinyl acetate, polyacrylic acid ester,
Polymethacrylic acid ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin,
It is used in a form bound with various binder resins such as epoxy resin, urethane resin, cellulose ester, and cellulose ether, or in a form in which fine particles are vapor-deposited. When the binder resin is used, it is used in a range of 30 to 500 parts by weight of the charge generating substance with respect to 100 parts by weight of the binder resin, and the film thickness thereof is usually 0.1 to 1 μm, particularly 0.15 to 0. 6 μm is preferred.

Examples of the charge-transporting substance for the charge-transporting layer include electron-withdrawing substances such as 2,4,7-trinitrofluorenone and tetracyanoquinodimethane, carbazole, and the like.
Heterocyclic compounds such as indole, imidazole, oxazole, pyrazole, oxadiazole, pyrazoline, and thiadiazole, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, or heavy chains having groups of these compounds in the main chain or side chain. An electron-donating substance such as coalesced. A low molecular weight compound that is not a polymer is particularly preferable. A binder resin is blended with these charge transport materials. The charge transport layer may optionally contain various additives such as an antioxidant and a sensitizer. The thickness of the charge transport layer is 10 to 50 μm
m, preferably 10 to 40 μm.

In the case of dispersion type, the above-mentioned polycarbonate resin of the present invention is used as the binder resin, and the resin 100
The charge transport material is preferably used in the range of 30 to 150 parts by weight based on parts by weight. The film thickness is usually 5-5
0 μm, preferably 10 to 30 μm is suitable. If necessary, various additives such as antioxidants and sensitizers may be included.

In the case of the dispersion type photosensitive layer, the above charge generating substance is dispersed in the charge transporting medium composed of the binder resin and the charge transporting substance having the above-mentioned compounding ratio. In that case, it is necessary that the particle size of the charge generating substance is sufficiently small, and preferably 1 μm or less, more preferably 0.5 μm.
Used below. If the amount of the charge generating substance dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if the amount is too large, there are adverse effects such as a decrease in charging property and a decrease in sensitivity. For example, preferably 0.5 to 50% by weight. %, More preferably 1 to 20% by weight.

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

In order to form the photosensitive layer or the charge transport layer on the conductive support, the coating solution is usually prepared by mixing the polycarbonate resin of the present invention, the charge transport material and other additives into a suitable solvent. It is preferably applied on the support by dip coating and then dried. The coating liquid for electrophotographic photoreceptor of the present invention refers to this coating liquid.

Further, these photoreceptors may be provided with an overcoat layer mainly composed of a known thermoplastic or thermosetting polymer as the outermost surface layer. These photosensitive layers are roll coating, bar coating, dip coating, spray coating, multi-nozzle coating.
It is formed on the conductive support by a known method such as coating. Examples of the conductive support provided with the photosensitive layer include metal materials such as aluminum, stainless steel and nickel, polyester films having a conductive layer such as aluminum, copper, palladium, tin oxide and indium oxide on the surface thereof, paper and glass. Insulating support of is used.

A publicly known barrier layer which is usually used may be provided between the conductive support and the photosensitive layer.
Examples of the barrier layer include an inorganic layer such as aluminum anodic oxide coating, aluminum oxide and aluminum hydroxide, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, and other organic layers. Layers are used. The thickness of the barrier layer is 0.1 to 20
The range of μm is preferable, and the range of 0.1 to 10 μm is most effective. As a method for forming each layer, a known method such as sequentially coating a coating solution obtained by dissolving or dispersing a substance contained in the layer in a solvent can be applied.

[0065]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Further, each measured value in the examples is obtained by the following method. (1) Viscosity average molecular weight (Mv) It was calculated using the following formula from ηSP measured at 20 ° C. using a 0.6 g / dl methylene chloride solution of an oligomer or a polymer.

[0066]

[Number 1] _{η SP /C=[η](1+0.28η SP) η SP =} 1.23 × 10 -4 Mv 0.83

Calculated from (2) Concentration of oligomeric terminal chloroformate group (CF
Group) After diluting the oligomer composition solution with methylene chloride, aniline and pure water were added, and titration was carried out with normal pH NaOH using phenolphthalein as an indicator.

(3) Concentration of phenolic OH group at oligomer terminal (OH group) After diluting the oligomer composition solution with methylene chloride, titanium tetrachloride and acetic acid solution were added to develop color, and a spectrophotometer (Hitachi Ltd. UV- 160 type) was used to measure the absorbance at a wavelength of 546 nm. Separately, the extinction coefficient was determined using the methylene chloride solution of the aromatic diol used in the production of the oligomer composition, and the amount of terminal phenolic OH groups of the oligomer was quantified.

(4) Amount of unreacted tert-butylphenol and PTBPC in oligomer Oligomer composition solution was subjected to liquid chromatography (L
C) (Condition: n-hexane / methylene chloride (1/1) → change to 100% methylene chloride, detector: U
V270 nm, apparatus: Shimadzu LC-9A) The amount of unreacted p-t-butylphenol and the amount of PTBPC in the sample were calculated from the area correction coefficient obtained in advance. In addition, unreacted p-
The amount of t-butylphenol was shown as a ratio (%) to the amount of p-t-butylphenol charged.

(5) Concentration of Chloroformate Group at the Molecular Terminal of Polycarbonate Resin About 1 g of the polycarbonate resin was weighed, and methylene chloride was added to
0 ml was added and dissolved. To this, 2 ml of a 1 wt% methylene chloride solution of 4- (p-nitrobenzyl) pyridine was added to develop color, and the absorbance at a wavelength of 440 nm was measured using a spectrophotometer (manufactured by Hitachi Ltd., Model 330). Separately, the extinction coefficient was determined using a methylene chloride solution of phenylchloroformate, and the amount of chloroformate groups in the sample was quantified.

(6) Polycarbonate resin Amount of nitrogen incorporated at the molecular end of the polycarbonate resin was measured with a total nitrogen analyzer (TN-10) manufactured by Mitsubishi Chemical Corporation using about 20 mg of the polycarbonate resin.

(7) Polycarbonate Resin Amount of monophenol group at the terminal of the molecule Polycarbonate resin (about 0.1 g) was weighed and dissolved in 2 ml of methylene chloride, and then 1.0 N potassium hydroxide was added.
After adding 20 ml of a methanol solution at 60 ° C. for 1 hour, the hydrolyzed monophenol was measured by LC (conditions: methanol / water = 4/6, detector: UV270 nm, device:
Shimadzu LC-9A) The amount of monophenol group at the molecular end in the sample was calculated from the area correction coefficient obtained in advance.

(8) Ratio of the amount of monophenol groups at the molecular ends to the total amount of terminal groups of the polycarbonate resin molecule: Calculated by the following formula. Molecular terminal monophenol group amount / (molecular terminal monophenol + molecular terminal OH group amount + molecular terminal chloroformate group amount) x 10
0 (%) (9) Viscosity of coating liquid A 10% dioxane solution of polycarbonate resin was prepared as a coating liquid for forming a charge transfer layer, and was prepared by Tokyo Keiki Co., Ltd.
The viscosity of the prepared liquid at 25 ° C. was measured by a B-type viscometer manufactured by K.K.

[Examples 1 to 5] Hydrosulfite 0.01 was added to 1 or 2 kinds of aromatic diols, sodium hydroxide, and 101.1 kg / hour of water in the amounts shown in Table 1.
Dissolve at 35 ° C. in the presence of 8 kg / hr, then cool to 25 ° C. aqueous phase, and cool to 5 ° C. methylene chloride 6
0.5kg / h organic phase, 6mm inner diameter, 8m outer diameter
m stainless steel pipe, mixed in the same pipe, and further homomixer (manufactured by Tokushu Kika Co., Ltd., product name TK
The emulsion was prepared by emulsification using Homomic Line Flow LF-500 type).

The emulsion of the aqueous solution of the sodium salt of aromatic diol (aqueous phase) and methylene chloride (organic phase) thus obtained was branched from a homomixer to give an inner diameter of 6 m.
m, the outer diameter is 8 mm, and the inner diameter is 6
In a polytetrafluoroethylene pipe reactor having a length of mm and a length of 34 m, liquefied phosgene shown in Table 1 supplied from a pipe separately cooled here at 0 ° C. was contacted.

The above emulsion was subjected to phosgenation and oligomerization reaction while flowing through phosgene and a pipe reactor at a linear velocity of 1.7 m / sec for 20 seconds. At this time, the reaction temperature was adjusted to 60 ° C., and external cooling was performed to 35 ° C. before entering the next oligomerization tank. The oligomerized emulsion thus obtained from the pipe reactor is further introduced into a reaction tank equipped with a stirrer and having an internal volume of 50 liters, and the mixture is stirred at 30 ° C. under a nitrogen gas atmosphere to be oligomerized. After completely consuming unreacted BPA-Na existing therein, the aqueous phase and the organic phase were separated by standing to obtain a solution of oligomer in methylene chloride.

Upon the oligomerization, a 2% by weight aqueous solution of triethylamine and 24 parts of pt-butylphenol were used.
A weight% methylene chloride solution was added at a flow rate shown in Table 1,
It was added to the oligomerization tank. At the time of adding pt-butylphenol, the content of phosgene in the reaction solution in the oligomerization tank was 0.001% by weight or less.
At this time, the viscosity average molecular weight (Mv) of the oligomer, the terminal chloroformate group concentration and the terminal phenolic OH group concentration, the amount of unreacted pt-butylphenol and the amount of PTBPC in the oligomer composition were measured. Described.

50 kg of a solution of the above oligomer composition in methylene chloride was charged into a reactor having an internal volume of 150 L and equipped with a Faudler blade, and methylene chloride 2 for dilution was added thereto.
5 kg was added, 25 wt% sodium hydroxide aqueous solution in an amount shown in Table 1, 6 kg of water, and 2.2 g of triethylamine were added, and the mixture was stirred at 10 ° C. under a nitrogen gas atmosphere, and 1
Polycondensation reaction was performed for 20 minutes to obtain a polycarbonate resin.

To this reaction solution, 30 kg of methylene chloride and 7 kg of water were added, and after stirring for 20 minutes, the stirring was stopped,
The aqueous and organic phases were separated. 0.1N to the separated organic phase
After adding 20 kg of hydrochloric acid and stirring for 15 minutes to extract triethylamine and a small amount of the remaining alkaline component, stirring was stopped and the aqueous phase and the organic phase were separated. Further, 20 kg of pure water was added to the separated organic phase, and after stirring for 15 minutes, the stirring was stopped and the aqueous phase and the organic phase were separated. This operation was repeated (3 times) until chlorine ions in the extracted waste water were not detected.

The purified polycarbonate resin solution thus obtained was faded into warm water to obtain polymer powder and dried in a ventilating dryer under a nitrogen atmosphere at 120 ° C. for 48 hours. In addition, in order to confirm reproducibility in each example, each step was performed twice. Regarding the polycarbonate resin obtained in each example (hereinafter referred to as “C-1” to “C-5”), the average molecular weight (Mv), the molecular terminal OH group amount (OH), and the molecular terminal relative to the total molecular terminal group amount. The ratio of the amount of monophenol group and the viscosity of the coating solution were measured, and the results are shown in Table 1. A polycarbonate resin having a controlled molecular end group amount and a controlled molecular weight was obtained with good reproducibility, and the viscosity of the coating solution was stable.

Comparative Example 1 Example 1 was repeated except that a methylene chloride solution of p-t-butylphenol was introduced into a pipe reactor, then contacted with phosgene, and the temperature during polycondensation was 30 ° C. The same operation was performed. [Comparative Example 2] The same operation as in Example 2 except that the methylene chloride solution of p-t-butylphenol was introduced into the pipe reactor, brought into contact with phosgene, and the temperature during the polycondensation was changed to 30 ° C. I went.

Comparative Example 3 As in Example 3, except that the methylene chloride solution of p-t-butylphenol was introduced into the pipe reactor, then contacted with phosgene, and the temperature during polycondensation was 30 ° C. The same operation was performed. [Comparative Example 4] The same operation as in Example 3 was performed except that a methylene chloride solution of p-t-butylphenol was added during polycondensation and the temperature during polycondensation was changed to 30 ° C.

Comparative Example 5 Example 4 was repeated except that the methylene chloride solution of p-t-butylphenol was introduced into the pipe reactor, then contacted with phosgene, and the temperature during polycondensation was 30 ° C. The same operation was performed. [Comparative Example 6] The same operation as in Example 5 was carried out except that in methylene chloride solution of pt-butylphenol was added during polycondensation and the temperature during polycondensation was changed to 30 ° C.

Example 1 was also applied to these Comparative Examples 1 to 6.
In order to confirm the reproducibility in the same manner as in ~ 5, each was carried out twice, and the obtained polycarbonate resin (hereinafter "C-6" ~
Various properties were evaluated for "C-11"), and the results are shown in Table 2. The molecular end groups and molecular weights of the obtained polycarbonate resin were not reproducible due to variations in molecular weight. As a result, the viscosity of the coating solution also fluctuates greatly and cannot be used as it is as a coating solution, and it is necessary to blend polycarbonate resins having different molecular weights to adjust the viscosity.

[Example 6] The respective oligomers obtained in Examples 1 and 2 were mixed at a ratio shown in Table 3 to give an internal volume of 1
A 50 liter reactor equipped with a Faudler blade was charged, and 25 kg of methylene chloride for dilution was added to the reaction tank.
Weight% sodium hydroxide aqueous solution 5.36 kg, water 6 k
g and 2.2 g of triethylamine were added, the mixture was stirred at 10 ° C. under a nitrogen gas atmosphere, and a polycondensation reaction was performed for 120 minutes to obtain a polycarbonate resin.

To this reaction solution, 30 kg of methylene chloride and 7 kg of water were added, and after stirring for 20 minutes, the stirring was stopped,
The aqueous and organic phases were separated. 0.1N to the separated organic phase
After adding 20 kg of hydrochloric acid and stirring for 15 minutes to extract triethylamine and a small amount of the remaining alkaline component, stirring was stopped and the aqueous phase and the organic phase were separated. Further, 20 kg of pure water was added to the separated organic phase, and after stirring for 15 minutes, the stirring was stopped and the aqueous phase and the organic phase were separated. This operation was repeated (3 times) until chlorine ions in the extracted waste water were not detected. The purified polycarbonate resin solution thus obtained was faded into warm water to obtain polymer particles, which were dried in a ventilating dryer at 120 ° C. for 48 hours under a nitrogen atmosphere.

Comparative Example 7 The respective oligomers obtained in Examples 1 and 2 without introducing a methylene chloride solution of p-t-butylphenol during the oligomerization reaction were mixed in the proportions shown in Table 3 to give an internal volume. A 150 liter reactor equipped with a Faudler blade was charged, and 25 methylene chloride for dilution was added to this.
25 kg by weight of sodium hydroxide aqueous solution (5.08 kg), water (6 kg), triethylamine (2.2 g), and 24% methylene chloride solution (0.61 kg) of p-t-butylphenol are added (0.61 kg) under nitrogen gas atmosphere.
The mixture was stirred at 0 ° C. and polycondensation reaction was performed for 120 minutes to obtain a polycarbonate resin.

To this reaction solution, 30 kg of methylene chloride and 7 kg of water were added, and after stirring for 20 minutes, the stirring was stopped,
The aqueous and organic phases were separated. 0.1N to the separated organic phase
After adding 20 kg of hydrochloric acid and stirring for 15 minutes to extract triethylamine and a small amount of the remaining alkaline component, stirring was stopped and the aqueous phase and the organic phase were separated. Further, 20 kg of pure water was added to the separated organic phase, and after stirring for 15 minutes, the stirring was stopped and the aqueous phase and the organic phase were separated. This operation was repeated (3 times) until chlorine ions in the extracted waste water were not detected.

The purified polycarbonate resin solution thus obtained was faded into warm water to obtain polymer powder and dried in a ventilating dryer at 120 ° C. for 48 hours under a nitrogen atmosphere. In order to confirm reproducibility in Example 6 and Comparative Example 7 as well, various properties were evaluated for the polycarbonate resin (hereinafter referred to as “C-12” and “C-13”) obtained by carrying out twice each. The results are shown in Table 3. In Example 6, a stable molecular end group amount, molecular weight, and coating liquid can be obtained, whereas in Comparative Example 7, there are variations in the molecular end group amount and molecular weight, there is no reproducibility, and the viscosity of the coating liquid also varies greatly. It could not be used as a liquid, and it was necessary to blend polycarbonate resins having different molecular weights to adjust the viscosity.

[0090]

[Table 1]

[0091]

[Table 2]

[0092]

[Table 3]

Bisazo compound 1 represented by the following (A)
0 parts by weight was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2, and the mixture was pulverized and dispersed by a sand grind mill. The pigment dispersion obtained here was used as polyvinyl butyral (Sekisui Chemical Co., Ltd., trade name BH
-3) was added to the 5% dimethoxyethane solution to finally prepare a dispersion having a solid content concentration of 4.0%.

[0094]

[Chemical 10]

An aluminum cylinder having an outer diameter of 80 mm, a length of 340 mm and a wall thickness of 2.0 mm, the surface of which was mirror-finished, was dip-coated on the dispersion liquid thus obtained, and the dry film thickness was about 0.4 μm. The charge generation layer was provided so that
Next, this aluminum cylinder was obtained by dissolving 90 parts by weight of a hydrazone compound represented by (B) below and 100 parts by weight of the polycarbonate resin obtained in Examples 1 to 3 and Comparative Example 2 in 900 parts by weight of dioxane. A photoreceptor was prepared by dip coating in a coating solution and forming a charge transfer layer so that the film thickness after drying was 20 μm.

[0096]

[Chemical 11]

The thus prepared photoconductor was mounted on an evaluation machine simulating a copying machine or a printer, and a copy test was performed on 100,000 sheets to measure the most stable electric characteristics at that time. The results are shown in Table 4. Here, a method of measuring each potential will be briefly described. The developing tank of the copying machine was removed, and an electrometer sensor was attached to the part. Next, place a half-white original document and a half-black original document on the original plate of the copying machine in half and measure the potential of the black background portion as the charging potential (Vo) and the potential of the white background portion as the sensitivity (VL) when copying this original document. did. The potential remaining after static elimination was measured as the residual potential (Vr). Table 4 shows the evaluation results using the polycarbonate resins produced in Examples 1 to 7 and Comparative Examples 1 to 7.

[0098]

[Table 4]

[0099]

INDUSTRIAL APPLICABILITY The polycarbonate of the present invention is excellent in the controllability of the molecular weight and the molecular end group and can be produced with good reproducibility. Further, by using this polycarbonate resin, an electrophotographic photoreceptor having good electric characteristics is provided. You can

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshimitsu Inoue             1-1 Kurosaki Shiroishi, Hachiman Nishi Ward, Kitakyushu City, Fukuoka Prefecture               Within Mitsubishi Chemical Corporation (72) Inventor Shigeo Higashi             1-1 Kurosaki Shiroishi, Hachiman Nishi Ward, Kitakyushu City, Fukuoka Prefecture               Within Mitsubishi Chemical Corporation F-term (reference) 2H068 AA13 BB26 EA04

Claims (9)

[Claims] 1. An electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is a polycarbonate resin satisfying the following a) to d). A) It is obtained by polycondensation of at least one aromatic diol and a carbonate-forming compound in the presence of monophenols, and b) the amount of OH groups at the molecular terminals is 20 μeq / g or less, and c) In addition, the ratio of the amount of monophenols at the molecular end to the total amount of terminal ends of the molecule is 90% or more, and d) the viscosity average molecular weight is 5,000 to 100,000. 2. A coating liquid for an electrophotographic photoreceptor, which contains at least an organic solvent, a charge transfer material, and a polycarbonate resin satisfying the following a) to d). A) It is obtained by polycondensation of at least one aromatic diol and a carbonate-forming compound in the presence of monophenols, and b) the amount of OH groups at the molecular terminals is 20 μeq / g or less, and c) In addition, the ratio of the amount of monophenols at the molecular end to the total amount of terminal ends of the molecule is 90% or more, and d) the viscosity average molecular weight is 5,000 to 100,000. 3. A viscosity average molecular weight of 500 to 10,000 obtained by reacting at least one aromatic diol with a carbonate-forming compound in the presence of a monophenol represented by the general formula Ar—OH. A carbonate oligomer composition, wherein the ratio of unreacted monophenols to the charged monophenols in the oligomer composition is 50% or less, and the content of the compound represented by the following general formula (1) is 0. A carbonate oligomer composition characterized by being 005% by weight or less. [Chemical 1] (However, Ar represents an aromatic ring residue which may be substituted.) 4. The carbonate oligomer composition according to claim 3, wherein the carbonate oligomer composition has a structural unit represented by the following general formula (2). [Chemical 2] Or a single bond, R ¹ and R ² are a hydrogen atom or a carbon number of 1 to
20 alkyl groups, optionally substituted aryl groups,
Or a halogenated alkyl group, Z is a substituted or unsubstituted carbocycle having 4 to 20, Y ¹ to Y ⁸ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms. Represents an optionally substituted aryl group or a halogenated alkyl group. ) 5. A method for producing a carbonate oligomer composition having a viscosity average molecular weight of 500 to 10,000 by reacting an aromatic diol with a carbonate-forming compound in the presence of a monophenol, wherein A method for producing a carbonate oligomer composition, which comprises mixing monophenols after the reaction with a carbonate-forming compound proceeds and the concentration of the carbonate-forming compound becomes 0.001% by weight or less. 6. The aromatic diol is represented by the following general formula (3):
The method for producing the carbonate oligomer composition according to claim 4, represented by: [Chemical 3] Or a single bond, R ¹ and R ² are a hydrogen atom or a carbon number of 1 to
20 alkyl groups, optionally substituted aryl groups,
Or a halogenated alkyl group, Z is a substituted or unsubstituted carbocycle having 4 to 20, Y ¹ to Y ⁸ are each independently a hydrogen atom, a halogen atom, or an alkyl group having 1 to 20 carbon atoms. Represents an optionally substituted aryl group or a halogenated alkyl group. ) 7. After reacting at least one aromatic diol with a carbonate-forming compound to reduce the concentration of the carbonate-forming compound to 0.001% by weight or less,
Mixing monophenols, average viscosity molecular weight 500 ~
10,000, a step of obtaining a carbonate oligomer composition having a ratio of unreacted monophenols to charged monophenols of 50% or less, and then polycondensation of the carbonate oligomer composition in the presence of an alkali to obtain a viscosity average molecular weight of 5, A method for producing a polycarbonate resin, comprising the step of obtaining 000 to 100,000 polycarbonate resin. 8. An electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is obtained by polycondensing the carbonate oligomer composition according to claim 3 or 4 in the presence of an alkali. And a polycarbonate resin having a viscosity average molecular weight of 5,000 to 100,000 as a main component. 9. An electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is a carbonate oligomer composition obtained by the method according to claim 5 or 6 in the presence of an alkali. Obtained by polycondensation to give a viscosity average molecular weight of 5,000 to 10
An electrophotographic photosensitive member comprising, as a main component, 30,000 polycarbonate resins.