JP2002287384A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having preferable wear resistance compared to a conventional electrophotographic photoreceptor. SOLUTION: In the electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, the binder resin in the photosensitive layer is a polycarbonate derived from pentacyclo pentadecane dimethanols expressed by general formula (1) and/or (2) and bisphenols expressed by general formula (3) with 0 to 9 molar ratio of general formula (a)/[general formula (1) + general formula (2)] and 0.3 to 2.0 dl/ g limiting viscosity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member. More specifically, the present invention relates to an electrophotographic photosensitive member using a specific polycarbonate resin as a binder.

[0002]

2. Description of the Related Art At present, electrophotographic technology has a high speed and a high image quality.
Widely applied to fax and the like. Conventionally, inorganic photoconductive materials such as selenium, selenium / tellurium alloy, selenium / arsenic alloy, and cadmium sulfide have been mainly used as electrophotographic photoreceptors in this electrophotographic technique. However, in view of toxicity, safety, price, productivity and the like, recently, an electrophotographic photosensitive member using an organic photoconductive substance has been developed.

[0003] When the organic photoconductive substance is a low molecular substance, it is generally used to form a coating film by mixing with a binder resin. Examples of the binder resin include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, various thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy resin, epoxy resin, and silicone resin, and thermosetting. Resin resins have been used. Among these various resins, polycarbonate resins have relatively excellent properties and are often used.

It has been reported that various polycarbonate resins are used as a binder resin.
No. 0-172444 discloses that a polycarbonate resin from bisphenol Z is used as a binder resin, and JP-A-63-170647 discloses that a polycarbonate resin from bisphenol A is used as a binder resin.

[0005] These known organic photoconductive materials (OP
Regarding the electrophotographic photoreceptor (OPC photoreceptor) using C) and various binder resins, an electrophotographic photoreceptor comparable to an electrophotographic photoreceptor using an inorganic photoconductive substance in terms of sensitivity and the like has been obtained.

[0006] These OPC photoreceptors can be easily formed into thin films by a cast film forming method, are suitable for mass production, and are relatively inexpensive. Although the OPC photoreceptor has such excellent surface, it has a problem of inferior abrasion resistance, and improvement has been required.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic electrophotographic photosensitive member having better abrasion resistance than conventional organic electrophotographic photosensitive members.

[0008]

The present inventors have conducted intensive studies to solve the conventional problems, and as a result, the electrophotographic photoreceptor using a specific polycarbonate resin as a binder has good abrasion resistance. It has been found that the present invention has been completed.

That is, the present invention relates to an electrophotographic photosensitive member having a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is pentacyclo represented by the general formula (1) and / or (2). A polycarbonate derived from pentadecane dimethanol and a bisphenol represented by the general formula (3), wherein the polycarbonate is represented by the general formula (3) / [general formula (1)
+ The general formula (2)] is a molar ratio of 0 to 9 and an intrinsic viscosity of 0.3 to 2.0 dl / g.

Embedded image

Embedded image

Embedded image (Wherein R ₁ and R ₂ are each independently a hydrogen atom,
A halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a cycloalkoxyl group having 6 to 10 carbon atoms, or Represents an aryloxy group having 6 to 10 carbon atoms. P and q represent the number of substituents, and are integers from 0 to 4. X is -C (R
₃ ) (R ₄ ) —, —O—, —CO—, —S—, —SO— or —SO ₂ —, wherein R ₃ and R ₄ are each independently a hydrogen atom, a group having 1 to 10 carbon atoms. It is an alkyl group or an aryl group having 6 to 10 carbon atoms, and R ₃ and R ₄ may combine with each other to form a ring. )

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarbonate resin according to the present invention can be obtained by reacting general formulas (1) and / or (2) and general formula (3) with a carbonate-forming compound. Examples of the carbonate-forming compounds include phosgene, diaryl carbonates such as diphenyl carbonate and ditolyl carbonate.

The molar ratio of the general formula (3) / [general formula (1) + general formula (2)] is from 0 to 9, preferably from 0 to 3. An increase in the amount of the general formula (3) is not preferable because the abrasion resistance, which is an effect of the present invention, deteriorates.

To improve various physical properties, it is possible to copolymerize the general formula (3), but if the amount of the compound represented by the general formula (3), particularly the general formula (4) is increased more than necessary, the Tg will increase. And it becomes difficult to take out the resin from the reactor after the polymerization, which is not preferable.

The starting materials for producing the polycarbonate of the present invention, pentacyclopentadecane dimethanol and the bisphenols of the general formula (3), preferably have a purity of at least 99%. If the purity is low, the degree of yellow coloring increases, the reactivity decreases, and it becomes difficult to control the polymerization.

The pentacyclopentadecane dimethanol represented by the general formulas (1) and (2) has a structural isomer and a stereoisomer, respectively. May be used alone, or a mixture in which each isomer is mixed in an arbitrary ratio may be used. Further, pentacyclopentadecane dimethanol represented by the general formula (1) or (2) may be used alone, or a mixture of the general formulas (1) and (2) at an arbitrary ratio may be used. In the present invention, pentacyclopentadecane dimethanol is a mixture of all isomers represented by the general formulas (1) and (2) unless otherwise specified. Purity refers to the sum of all isomers in the total amount. Say what you divided.

In the polycarbonate resin according to the present invention, bisphenols of the general formula (3) include 2,2-bis (4-hydroxyphenyl) propane (bisphenol A; BPA) and 2,2-bis ( 4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 4,4′-biphenoldiol, bis (4-
(Hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) ketone 1 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z; BPZ), 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane, 3,3,5-trimethyl-1,1-bis (4-hydroxyphenyl) cyclohexane and the aforementioned general formula (4) can be given. 2,2-Bis (4-hydroxyphenyl) propane is preferred from the viewpoint of availability.

The compound of the general formula (4) includes 9,9-
Bis (4-hydroxy-2-methylphenyl) fluorene,
9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 9,9-bis (4-hydroxyphenyl) fluorene,
9-bis (4-hydroxy-2-ethylphenyl) fluorene, 9,9-bis (4-hydroxy-3-ethylphenyl) fluorene, 9,9-bis (4-hydroxy-3,5-dimethylphenyl) fluorene And so on. From the viewpoint of reactivity, 9,9-bis (4-hydroxy-2-methylphenyl) fluorene and 9,9-bis (4-hydroxy-3-methylphenyl) fluorene are preferred.

The polycarbonate of the present invention can be produced by a known method used for producing a polycarbonate from bisphenol A and a carbonate-forming compound, for example, a direct reaction of a bisphenol with phosgene (phosgene method),
Alternatively, a method such as a transesterification reaction between a bisphenol and a diaryl carbonate (a transesterification method) can be employed.

In the phosgene method and the transesterification method, the transesterification method is preferable in consideration of the reactivity of pentacyclopentadecanedimethanol as a raw material.

In the transesterification method, the pentacyclopentadecane dimethanol and the diaryl carbonate are mixed, or pentacyclopentadecane dimethanol and a bisphenol are mixed with the diaryl carbonate, and the mixture is reacted at a high temperature under reduced pressure. The reaction is usually carried out at a temperature in the range of 150 to 350 ° C., preferably 200 to 300 ° C., and the final pressure is preferably 0.2 kPa or less, and phenols derived from the diaryl carbonate produced by the transesterification reaction Is distilled out of the system. The reaction time depends on the reaction temperature and the degree of pressure reduction, but is usually about 1 to 10 hours. The reaction is preferably performed in an atmosphere of an inert gas such as nitrogen or argon. If desired, the reaction may be carried out by adding a molecular weight regulator, an antioxidant or a branching agent. These methods are known, and specifically,
A method described in Japanese Patent Application Laid-Open No. 0-30286 can be used.

In the phosgene method, the pentacyclopentadecane dimethanol and phosgene, or pentacyclopentadecane dimethanol and bisphenols are reacted with phosgene, usually in the presence of an acid binder and a solvent. Examples of the acid binder include pyridine and hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide. Examples of the solvent include methylene chloride, chloroform, chlorobenzene, and xylene. Further, a catalyst such as a tertiary amine such as triethylamine or a quaternary ammonium salt is used to promote the polycondensation reaction, and phenol, pt-butylphenol, p-cumylphenol is used for controlling the degree of polymerization. It is preferable to add a monofunctional compound such as a long-chain alkyl-substituted phenol as a molecular weight regulator. If desired, a small amount of an antioxidant such as sodium sulfite or hydrosulfite or a branching agent such as phloroglucin or isatin bisphenol may be added. The reaction is usually carried out at a temperature of 0 to 150 ° C, preferably 5 to 40 ° C. The reaction time depends on the reaction temperature, but is usually 0.5 minutes to 10 hours, preferably 1 minute to 2 hours. During the reaction, it is desirable to maintain the pH of the reaction system at 10 or more.

The polycarbonate resin synthesized by these reactions is easily formed by known wet molding such as a solution casting method, a casting method, a spray method, and a dip coating method (dip method) used in the production of an electrophotographic photosensitive member. It is possible. In order to obtain sufficient film strength of the electrophotographic photoreceptor formed by wet molding, the intrinsic viscosity is preferably from 0.3 to 2.0 dl / g. 0.
It is preferably from 4 to 1.5 dl / g.

The electrophotographic photoreceptor of the present invention may have a single-layer photoconductive layer on a conductive support, or may have a layered type with separated functions. Recently, a laminated electrophotographic photoreceptor composed of two layers, a charge generation layer that generates charges by exposure and a charge transport layer that transports charges, has become mainstream.
Further, an undercoat layer, a protective layer, an adhesive layer, and the like may be provided as necessary.

The conductive support of the present invention includes a metal material such as aluminum, stainless steel and nickel, a polyester film provided with a conductive layer such as aluminum, palladium, tin oxide and indium oxide on its surface, and phenol. Resin, paper and the like are used.

The charge generation layer of the present invention can be formed by a known method.
Formed on a conductive support. As the charge generating substance,
For example, organic pigments such as azoxybenzene-based, disazo-based, trisazo-based, benzimidazole-based, polycyclic quinoline-based, indigoid-based, quinacridone-based, phthalocyanine-based, perylene-based, and methine-based pigments can be used. These charge-generating substances can be used as fine particles such as polyvinyl butyral resin, polyvinyl formal resin, silicone resin, polyamide resin, polyester resin, polystyrene resin, polycarbonate resin, polyvinyl acetate resin, polyurethane resin, phenoxy resin, epoxy resin, and various types of cellulose. Used in a form dispersed in a binder resin.

The charge transporting layer of the present invention is formed on the charge generating layer by a known method using the polycarbonate resin of the present invention as a binder resin and dispersing a charge transporting substance. Examples of the charge transporting substance include polytetracyanoethylene; fluorenone compounds such as 2,4,7-trinitro-9-fluorenone; nitro compounds such as dinitroanthracene; succinic anhydride; maleic anhydride; dibromomaleic anhydride; Triphenylmethane compound; 2,5-di (4-dimethylaminophenyl)-
Oxadiazole compounds such as 1,3,4-oxadiazole; styryl compounds such as 9- (4-diethylaminostyryl) anthracene; carbazole compounds such as poly-N-vinylcarbazole; 1-phenyl-3-
Pyrazoline compounds such as (p-dimethylaminophenyl) pyrazoline; amine derivatives such as 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine;
1,1-bis (4-diethylaminophenyl) -4,4
Conjugated unsaturated compounds such as -diphenyl-1,3-butadiene; hydrazone compounds such as 4- (N, N-diethylamino) benzaldehyde-N, N-diphenylhydrazone; indole compounds, oxazole compounds, isoxazole compounds And nitrogen-containing cyclic compounds such as thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, pyrazoline compounds and triazole compounds; condensed polycyclic compounds. The charge transport materials may be used alone or in combination of two or more.

The charge-generating layer and the charge-transporting layer are formed by dissolving the above-mentioned charge-generating substance or the charge-transporting substance in a binder resin and a suitable solvent, respectively, and applying the solution by dip coating or spraying. , And can be formed by drying. This solvent can be roughly classified into two types, a halogen-based organic solvent and a non-halogen-based solvent. In general, a halogen-based solvent having low flammability is often used. In recent years, from the viewpoint of safety and environmental protection, the proportion of non-halogen solvents has been increasing, and the polycarbonate resin used in the present invention is also highly soluble in many non-halogen solvents.

Non-halogen solvents include aromatic solvents such as benzene, toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone; ether solvents such as tetrahydrofuran, dioxane and ethylene glycol diethyl ether; methyl acetate and ethyl acetate. And ester solvents such as ethylcellosolve, alcohol solvents such as methanol, ethanol and isopropanol, and dimethylformamide, dimethylsulfoxide and diethylformamide. Examples of the halogen-based solvent include methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, tetrachloroethane, and chlorobenzene. These solvents may be used alone regardless of whether they are non-halogen or halogen. These may be used in combination as a solvent for mixing.

The mixing ratio between the charge generating substance and the binder resin is preferably in the range of 10: 1 to 1:20. The thickness of this charge generation layer is 0.01 to 20 μm, preferably 0.1 to 20 μm.
1-2 μm is preferred.

The mixing ratio of the charge transport material to the binder resin is preferably in the range of 10: 1 to 1:10. The thickness of the charge transport layer is 2 to 100 μm, preferably 5 to 30 μm.
μm is preferred.

[0030]

The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 52.5 g of pentacyclopentadecane dimethanol
(0.2 mol), 43.3 g of diphenyl carbonate
(0.202 mol), and sodium hydrogen carbonate 5 × 1
0 ^-4 g (6 × 10 ^-6 mol) was placed in a 300 ml four-necked flask equipped with a stirrer and a distilling device, heated to 180 ° C. under a nitrogen atmosphere of 760 mmHg, and stirred for 30 minutes. Thereafter, the degree of pressure reduction was adjusted to 150 mmHg, and at the same time, the temperature was raised to 200 ° C at a rate of 60 ° C / hr,
The temperature was maintained for 40 minutes to carry out transesterification. Further, the temperature was raised to 225 ° C. at a rate of 75 ° C./hr.
The pressure was reduced to 0.15 kPa or less over time. Thereafter, the temperature was raised to 235 ° C. at a rate of 105 ° C./hr, and a total of 6
The reaction was carried out under stirring for a time, and after completion of the reaction, nitrogen was blown into the reactor to return to normal pressure, and the produced polycarbonate was taken out. The limiting viscosity at 20 ° C. of a solution of this polymer having a concentration of 0.5 g / dl in methylene chloride as a solvent is 0.
It was 70 dl / g.

Next, 10 parts of τ-type copper phthalocyanine, 5 parts of phenoxy resin, 5 parts of polyvinyl butyral resin, and 100 parts of dimethoxyethane were mixed on a polyethylene terephthalate film on which aluminum was deposited to a thickness of about 50 nm. Is applied using a coating liquid that has been subjected to a pulverizing and dispersing treatment, and dried to a thickness of about 0.5 μm
Was provided. Next, 50 parts of 4- (N, N-diethylamino) benzaldehyde-N, N-diphenylhydrazone, 50 parts of the polycarbonate resin obtained by the above synthetic polymerization, 350 parts of tetrahydrofuran,
Prepare the used coating solution, apply it on the charge generation layer,
After air drying, drying was performed at 100 ° C. for 8 hours, and a charge transport layer having a thickness of about 20 μm was provided to prepare a laminated electrophotographic photosensitive member. The evaluation of this electrophotographic photoreceptor was performed using Kawaguchi Electric Manufacturing Co., Ltd. E
The charging characteristics were examined with a PA-8100 electrostatic charging tester. For the abrasion resistance, the shaving amount was measured using a Taba abrasion tester manufactured by Suga Test Instruments Co., Ltd. Table 1 shows the results.

Example 2 In Example 1, 36.3 g (0.14 mol) of pentacyclopentadecanedimethanol, 2,2-bis (4-
13.7 g (0.06 mol) of hydroxyphenyl) propane, 43.3 g (0.202) of diphenyl carbonate
Mol), 5 × 10 ⁻⁴ g of sodium hydrogen carbonate (6 × 10 ⁻⁶⁾
Mol)), except for using the compound of Example 1. Table 1 shows the measurement results of physical properties of the obtained polycarbonate resin.

Example 3 In Example 1, 26.2 g (0.1 mol) of pentacyclopentadecanedimethanol, 22.8 g (0.1 mol) of 2,2-bis (4-hydroxyphenyl) propane, diphenyl carbonate 43.3 g (0.202
Mol), 5 × 10 ⁻⁴ g of sodium hydrogen carbonate (6 × 10 ⁻⁶⁾
Mol)), except for using the compound of Example 1. Table 1 shows the measurement results of physical properties of the obtained polycarbonate resin.

Example 4 In Example 1, 36.7 g (0.14 mol) of pentacyclopentadecanedimethanol, 9,9-bis (4-
(Hydroxy-3-methylphenyl) fluorene 22.7
g (0.06 mol), diphenyl carbonate 43.3
g (0.202 mol), sodium hydrogen carbonate 5 × 10 ^-4
The same operation as in Example 1 was performed except that g (6 × 10 ⁻⁶ mol) was used. Table 1 shows the measurement results of physical properties of the obtained polycarbonate resin.

Example 5 In Example 1, 26.2 g (0.1 mol) of pentacyclopentadecanedimethanol, 37.8 g of 9,9-bis (4-hydroxy-3-methylphenyl) fluorene were used.
(0.1 mol), 43.3 g of diphenyl carbonate
(0.203 mol), sodium hydrogen carbonate 5 × 10 ⁻⁴ g
(6 × 10 ⁻⁶ mol), except that the same operation as in Example 1 was performed. Table 1 shows the measurement results of physical properties of the obtained polycarbonate resin.

COMPARATIVE EXAMPLE 1 Instead of the polycarbonate resin of Example 1, commercially available B
PZ type homopolycarbonate resin (Mitsubishi Gas Chemical Co., Ltd.)
An evaluation test similar to that of Example 1 was performed using Iupilon PCZ manufactured by Idemitsu Co., Ltd., intrinsic viscosity 0.78 dl / g). Table 1 shows the results.

COMPARATIVE EXAMPLE 2 Instead of the polycarbonate resin of Example 1, commercially available B
PA type homopolycarbonate resin (Mitsubishi Gas Chemical Co., Ltd.)
An evaluation test similar to that in Example 1 was performed using Iupilon E-1000 manufactured by Idemitsu Co., Ltd., intrinsic viscosity: 0.61 dl / g). Table 1 shows the results.

[0039]

[Table 1]

(Explanation of symbols in Table 1) PCPDM: pentacyclopentadecanedimethanol BCFL: 9,9-bis (4-hydroxy-3-methylphenyl) fluorene BPA: 2,2-bis (4-hydroxyphenyl) propane BPZ: 1,1-bis (4-hydroxyphenyl) cyclohexane Intrinsic viscosity: 20 ° C., 0.5% dichloromethane solution, measured with a Huggins constant of 0.45. Initial potential: Initial charge amount (-V) when adjusted by a DC charger so that a current of 50 μA flows. Residual potential: Residual potential (-V) 4 seconds after exposure (10 Lux). Abrasion amount: Abrasion amount (mg) when a Taber abrasion test is performed after 1000 cycles of reciprocating motion with a load of 300 g, CS-17 wheels

[0041]

According to the electrophotographic photoreceptor of the present invention, by using a polycarbonate resin derived from pentacyclopentadecane dimethanol as a binder, the abrasion resistance is improved while maintaining the charging characteristics of the electrophotographic photoreceptor. . Therefore, the effect of stabilizing the electrophotographic image and extending the life of the photoconductor is expected.

Claims (5)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, wherein the binder resin of the photosensitive layer is:
A polycarbonate derived from a pentacyclopentadecane dimethanol represented by the general formula (1) and / or (2) and a bisphenol represented by the general formula (3), wherein the polycarbonate is represented by the general formula (3) / [general formula (1) + the general formula (2)] has a molar ratio of 0 to 9 and an intrinsic viscosity of 0.3 to 2.0.
dl / g. Embedded image Embedded image Embedded image (Wherein R ₁ and R ₂ are each independently a hydrogen atom,
A halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a cycloalkoxyl group having 6 to 10 carbon atoms, or Represents an aryloxy group having 6 to 10 carbon atoms. P and q represent the number of substituents, and are integers from 0 to 4. X is -C (R
₃ ) (R ₄ ) —, —O—, —CO—, —S—, —SO— or —SO ₂ —, wherein R ₃ and R ₄ are each independently a hydrogen atom, a group having 1 to 10 carbon atoms. It is an alkyl group or an aryl group having 6 to 10 carbon atoms, and R ₃ and R ₄ may combine with each other to form a ring. ) 2. The electrophotographic photoreceptor according to claim 1, wherein the molar ratio of general formula (3) / [general formula (1) + general formula (2)] is 0 to 3. 3. X in the general formula (3) is -C (R ₃ ).
2. The electrophotographic photosensitive member according to claim 1, wherein (R ₄ ) — and R ₃ and R ₄ are methyl groups. 4. The electrophotographic photosensitive member according to claim 1, wherein the general formula (3) is the general formula (4). Embedded image (Wherein, R ₅ and R ₆ are each independently a hydrogen atom,
A halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, a cycloalkoxyl group having 6 to 10 carbon atoms, or Represents an aryloxy group having 6 to 10 carbon atoms. R and s represent the number of substituents, and are integers from 0 to 4. ) 5. The electrophotographic photoreceptor according to claim 4, wherein in the general formula (4), R ₅ and R ₆ are methyl groups, and r and s are 1.