JPH08211632A - Polyester resin for binder of electrophotographic photo-receptor - Google Patents

Abstract

PURPOSE: To provide polyester resin having high wear resistance and high dye stuff dispersing ability, excellent in solubility, giving a low viscosity soln., not causing deterioration such as cracking and suitable for use as a binder for OPC by polymerizing dicarboxylic acid or its ester forming deriv. and diols including a specified dihydroxy compd. CONSTITUTION: Dicarboxylic acid or its ester forming deriv. and diols including a dihydroxy compd. represented by the formula are polymerized to obtain the objective polyester resin. The amt. of the dihydroxy compd. is >=10mol% of the total amt. of the diols. In the formula, R1 is 2-4C alkylene, each of R2 -R5 is H, 1-4C alkyl, aryl or aralkyl, R' is 1-4C alkyl, (n) is an integer of >=2 and (m) is an integer of 0 to 2(n+2). The dihydroxy compd. is typically 1,1-bis[4-(2- hydroxyethoxy)phenyl]-cyclohexane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder used in an electrophotographic photoreceptor having a charge generation layer and a charge transport layer on a support such as a metal drum or a polyethylene terephthalate film having a conductive layer formed on the surface thereof. It concerns a resin.

[0002]

2. Description of the Related Art Organic photoconductors (OPCs) used as photoconductors for copiers and printers are excellent in operability, stability, and economic efficiency, and thus are important images supporting the current information society. Reusable printing technology has made remarkable progress. OPC photoconductors currently in practical use are of the function-separated type in which the charge-generating part and the charge-transporting part are separated except for the initial type. This function-separated type photoconductor is roughly classified into two types according to the state of the charge generation material. One is a single-layer type photoreceptor in which a charge generating material and a charge transporting material are dissolved or dispersed in a single photoreceptor layer, and the other is a charge generating layer and a charge transporting layer in separate layers. It is a multi-layer type photoconductor that is separated and laminated.

When these photoconductors are used, the processes of exposure, toner adhesion, transfer, and residual toner removal are repeated. During this process, the surface of the photoconductor is scratched or abraded due to friction, resulting in problems such as a decrease in sensitivity and uneven transfer. Therefore, wear resistance is improved by OPC.
Has become an important issue. As means for solving this problem, for example, Idemitsu Technical Report (Vol. 36, 224)
, 1993) and Japanese Patent Publication No. 2-52257, it has been proposed to improve the binder resin. However, practically sufficient abrasion resistance has not been secured yet.

The properties required of the OPC binder are as follows:
In addition to the above abrasion resistance, (1) high dispersibility of the dye,
(2) Excellent solubility in organic solvents, low viscosity of solution, (3) No deterioration such as cracking, and (4) Good electrical sensitivity and small charge transfer material / binder ratio. Etc. Generally, it is known that the abrasion resistance is improved by increasing the molecular weight of the resin, but when the molecular weight is high, the performance of the above (2) is inferior and the production becomes difficult. At present, there is no satisfactory resin and it is unavoidable to use it properly according to the purpose.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have completed the present invention as a result of intensive investigations in view of the drawbacks of the prior art. The purpose is (1)
High abrasion resistance, (2) high dispersibility of dyes, (3) excellent solubility in organic solvents, low solution viscosity, (4) no deterioration such as cracks, (5) electricity It is to provide a polyester resin suitable for an OPC binder, which has a high optical sensitivity and a small charge transfer material / binder ratio. Still another object is to provide a polyester resin suitable as a binder for OPC, which can be industrially easily and inexpensively produced.

[0006]

The above-mentioned object of the present invention is a polyester resin which is polymerized from a dicarboxylic acid or its ester-forming derivative and a diol, wherein the diol is 10 mol% or more based on 100 as a total diol component. General formula (1)

Embedded image (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group and may be the same or different, and R ′ is an alkyl group having 1 to 4 carbon atoms. n is an integer of 2 or more, m is an integer of 0 or more and 2 (n + 2) or less. And a polyester resin for a binder for an electrophotographic photoreceptor, which comprises a dihydroxy compound represented by the formula (1).

The present invention will be described in detail below. The general formula (1) of the polyester

Embedded image It is a key part of the present invention to use a dihydroxy compound represented by as a copolymerization component. By using this, heat resistance is improved without impairing the moldability of the polyethylene terephthalate resin, and at the same time, it easily dissolves in a general-purpose organic solvent. Further, although the reason is not clear, by copolymerizing the dihydroxy compound,
Abrasion resistance as an OPC drum and dispersibility of OPC dye are improved.

The general formula (1) used in the present invention
The dihydroxy compound represented by may be any compound synthesized from cycloalkanone, and examples thereof include dihydroxy compounds derived from cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone and the like.

Specific examples of the dihydroxy compound derived from cyclopentanone include 1,1-bis [4-
(2-Hydroxyethoxy) phenyl] cyclopentane, 1,1-bis [4- (2-hydroxyethoxy)-
3-Methylphenyl] cyclopentane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] cyclopentane, 1,1-bis [4- (2-
Hydroxyethoxy) -3-ethylphenyl] cyclopentane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-diethylphenyl] cyclopentane,
1,1-bis [4- (2-hydroxyethoxy) -3-
Propylphenyl] cyclopentane, 1,1-bis [4
-(2-Hydroxyethoxy) -3,5-dipropylphenyl] cyclopentane, 1,1-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] cyclopentane, 1,1-bis [4- (2-Hydroxyethoxy) -3,5-diisopropylphenyl] cyclopentane, 1,1-bis [4- (2-hydroxyethoxy)
-3-n-butylphenyl] cyclopentane and the like can be mentioned.

Specific examples of the dihydroxy compound derived from cyclohexanone include 1,1-bis [4-
(2-Hydroxyethoxy) phenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy)-
3-Methylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] cyclohexane, 1,1-bis [4- (2-
Hydroxyethoxy) -3-ethylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-diethylphenyl] cyclohexane,
1,1-bis [4- (2-hydroxyethoxy) -3-
Propylphenyl] cyclohexane, 1,1-bis [4
-(2-Hydroxyethoxy) -3,5-dipropylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] cyclohexane, 1,1-bis [4- (2 -Hydroxyethoxy) -3,5-diisopropylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy)
-3-n-Butylphenyl] cyclohexane, 1,1-
Bis [4- (2-hydroxyethoxy) -3,5-di-
n-Butylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3-isobutylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-diisobutylphenyl ]
Cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3- (1-methylpropyl) phenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-bis ( 1-Methylpropyl) phenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3-phenylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy)-
3,5-diphenylphenyl] cyclohexane, 1,1
-Bis [4- (2-hydroxyethoxy) -3-benzylphenyl] cyclohexane, 1,1-bis [4- (2
-Hydroxyethoxy) -3,5-dibenzylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) phenyl] -4-methylcyclohexane, 1,1-bis [4- (2-hydroxyethoxy) ) Phenyl] -2,4,6-trimethylcyclohexane,
1,1-bis [4- (2-hydroxypropoxy) phenyl] cyclohexane, 1,1-bis [4- (2-hydroxybutoxy) phenyl] cyclohexane and the like can be mentioned.

Specific examples of the dihydroxy compound derived from cycloheptanone include 1,1-bis [4-
(2-Hydroxyethoxy) phenyl] cycloheptane, 1,1-bis [4- (2-hydroxyethoxy)-
3-Methylphenyl] cycloheptane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] cycloheptane, 1,1-bis [4- (2-
Hydroxyethoxy) -3-ethylphenyl] cycloheptane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-diethylphenyl] cycloheptane,
1,1-bis [4- (2-hydroxyethoxy) -3-
Propylphenyl] cycloheptane, 1,1-bis [4
-(2-Hydroxyethoxy) -3,5-dipropylphenyl] cycloheptane, 1,1-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] cycloheptane, 1,1-bis [4- (2-Hydroxyethoxy) -3,5-diisopropylphenyl] cycloheptane, 1,1-bis [4- (2-hydroxyethoxy)
Examples include -3-n-butylphenyl] cycloheptane.

The dihydroxy compound derived from cyclooctanone is specifically 1,1-bis [4-
(2-Hydroxyethoxy) phenyl] cyclooctane, 1,1-bis [4- (2-hydroxyethoxy)-
3-Methylphenyl] cyclooctane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] cyclooctane, 1,1-bis [4- (2-
Hydroxyethoxy) -3-ethylphenyl] cyclooctane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-diethylphenyl] cyclooctane,
1,1-bis [4- (2-hydroxyethoxy) -3-
Propylphenyl] cyclooctane, 1,1-bis [4
-(2-Hydroxyethoxy) -3,5-dipropylphenyl] cyclooctane, 1,1-bis [4- (2-hydroxyethoxy) -3-isopropylphenyl] cyclooctane, 1,1-bis [4- (2-Hydroxyethoxy) -3,5-diisopropylphenyl] cyclooctane, 1,1-bis [4- (2-hydroxyethoxy)
-3-n-butylphenyl] cyclooctane and the like can be mentioned.

Among these, 1,1-bis [4- (2
-Hydroxyethoxy) phenyl] cyclopentane,
1,1-bis [4- (2-hydroxyethoxy) -3-
Methylphenyl] cyclopentane, 1,1-bis [4-
(2-Hydroxyethoxy) -3,5-dimethylphenyl] cyclopentane, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy)- 3-methylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] cyclohexane, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclooctane, 1,1-bis [4-
(2-Hydroxyethoxy) -3-methylphenyl] cyclooctane, 1,1-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] cyclooctane and the like are preferable from the viewpoint of moldability.

The cycloalkane-based dihydroxy compounds synthesized from these cycloalkanones may be used alone or in combination of two or more kinds.

1,1-Bis [4- (2-hydroxyethoxy) phenyl] cyclohexane is obtained, for example, by adding ethylene oxide (hereinafter referred to as EO) to 1,1-bis (4-hydroxyphenyl) cyclohexane. At this time, in addition to the 2EO adduct in which ethylene oxide is added to both hydroxyl groups of phenol one molecule at a time, impurities such as 3EO adduct and 4EO adduct added in excess of several molecules may be contained. When the amount of impurities such as 4EO increases, the heat resistance of the polyester polymer is lowered, so that the purity of the 2EO adduct is preferably 85% or more, more preferably 95% or more.

The ratio of the dihydroxy compound represented by the general formula (1) to the total of all diol components is 10 m.
It is necessary to be ol% or more, preferably 30 m
It is ol% or more, more preferably 50 mol% or more. When it is less than 10 mol%, the molded body is easily deformed by heat, heat resistance is insufficient, and the dispersibility of the OPC dye and the solubility in an organic solvent are also reduced.

Further, when the transesterification method is used, the melt polymerization reaction is likely to proceed and the polymerization time is shortened.
It is preferably ol% or less. However, 95 mol
Even when it is more than%, it can be easily produced by a solution polymerization method or an interfacial polymerization method.

In the present invention, as the diol other than the dihydroxy compound represented by the general formula (1), those commonly used in polyester resins suitable for OPC binders can be used. For example, aliphatic glycols , A fluorene-based aromatic dihydroxy compound, a dihydroxy compound having an aromatic ring in the main chain and a side chain, a dihydroxy compound having an aromatic ring and sulfur in the main chain, a general formula Cp H
Examples thereof include dihydroxy compounds represented by ₂ pO (p is an integer) and derived from a linear alkanone containing branching, and methylols.

These may be used alone, or
You may use 2 or more types as needed.

The aliphatic glycols include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 1, Examples include 5-pentanediol, 1,4-pentanediol and 1,3-pentanediol.

Examples of the fluorene-based aromatic dihydroxy compound include fluorene-based dihydroxy compounds represented by the general formula (2), and specifically, 9,9-
Bis [4- (2-hydroxyethoxy) phenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) -3-methylphenyl] fluorene, 9,9-bis [4- (2-hydroxyethoxy) Examples include -3,5-dimethylphenyl] fluorene, and among these, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene is preferable.

[0022]

[Chemical 4]

(R ₆ is an alkylene group having 2 to 4 carbon atoms,
R ₇ , R ₈ , R ₉ and R ₁₀ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group and may be the same or different. )

Examples of the dihydroxy compound having an aromatic ring in the main chain and the side chain include a dihydroxy compound represented by the general formula (3), and specifically, 1,1-
Bis [4- (2-hydroxyethoxy) phenyl] -1
-Phenylethane and the like.

[0025]

Embedded image

(R ₁₁ is an alkylene group having 2 to 4 carbon atoms,
R ₁₂ , R ₁₃ , R ₁₄ and R ₁₅ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group and may be the same or different, and R ₁₆ is 1 to 6 carbon atoms. Is an alkyl group. )

Examples of the dihydroxy compound having an aromatic ring and sulfur in the main chain include compounds represented by the general formula (4), and specifically, bis- [4- (2-hydroxyethoxy) phenyl]. -Sulphone, Bis- [4- (2
-Hydroxyethoxy) -3-methylphenyl] -sulfone and the like.

[0028]

[Chemical 6]

(R ₁₇ is an alkylene group having 2 to 4 carbon atoms,
R ₁₈ , R ₁₉ , R ₂₀ and R ₂₁ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group and may be the same or different. )

Examples of the dihydroxy compound represented by the general formula Cp H ₂ pO (p is an integer) derived from a straight chain alkanone containing a branch include compounds represented by the general formula (5). , Specifically, 2,2-bis [4-
(2-hydroxyethoxy) phenyl] -propane,
2,2-bis [4- (2-hydroxyethoxy) -3,
5-dimethylphenyl] -propane, 2,2-bis [4
-(2-Hydroxyethoxy) -phenyl] -3-methylbutane, 2,2-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] -3-methylbutane, 2,2-bis [4- (2-Hydroxyethoxy) phenyl] -4-methylpentane, 2,2-bis [4-
(2-Hydroxyethoxy) -3-methylphenyl]-
4-methylpentane, 2,2-bis [4- (2-hydroxyethoxy) -3,5-dimethylphenyl] -4-methylpentane, 2,2-bis [4- (2-hydroxyethoxy) -3- Ethylphenyl] -4-methylpentane, 3,3-bis [4- (2-hydroxyethoxy)-
Phenyl] -hexane and the like can be mentioned.

[0031]

[Chemical 7]

(R ₂₂ is an alkylene group having 2 to 4 carbon atoms,
R ₂₃ , R ₂₄ , R ₂₅ and R ₂₆ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group and may be the same or different, and R ₂₇ and R ₂₈ are each having 1 carbon atom. To 10 alkyl groups. )

Examples of the methylols include tricyclodecane dimethylol, tricyclodecane diethylol, tricyclodecane dipropyrrole and tricyclodecane dibutyrol.

Of course, the compounds are not limited to these compounds, and they may be used alone or in combination of two or more kinds. Also, other dihydroxy compounds can be used.

Of the diols other than the dihydroxy compound represented by the general formula (1), the ratio of the aliphatic diol such as ethylene glycol to the total of all diols is
It is preferably at least 5 mol%, more preferably 1
It is 0 mol% or more. This is because when the low boiling point diol such as ethylene glycol is 5 mol% or more, melt polymerization is likely to proceed and the polymerization time is shortened.

The dicarboxylic acid used in the polyester resin of the present invention includes terephthalic acid, isophthalic acid,
2,6-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,
2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-
Naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,7 naphthalenedicarboxylic acid, 2,2'-biphenyldicarboxylic acid, 3,3'-biphenyldicarboxylic acid, 4,4'- Examples thereof include aromatic dicarboxylic acids such as biphenyldicarboxylic acid and 9,9-bis (4-carboxyphenylene) fluorene, and aliphatic dicarboxylic acids such as maleic acid, adipic acid, sebacic acid and decamethylenedicarboxylic acid.

Examples of the ester-forming derivative of the dicarboxylic acid include alkyl esters and the like.

These dicarboxylic acids or ester-forming derivatives thereof may be used alone or in combination of two or more as required.

The polyester resin of the present invention can be produced by selecting an appropriate method from known methods such as a transesterification method, a melt polymerization method such as a direct polymerization method, a solution polymerization method and an interfacial polymerization method. Regarding the reaction conditions such as the polymerization catalyst at that time, a conventionally known method can be used. Among them, the melt polymerization method is preferably used.

The intrinsic viscosity of the polyester resin of the present invention measured at 20 ° C. in chloroform is preferably 0.3.
Or more, more preferably 0.4 or more, most preferably 0.5 or more, but depending on the application, 0.6
More than that may be necessary. The intrinsic viscosity is preferably 0.3 or more from the viewpoint that the mechanical properties of the photoconductor, particularly abrasion resistance, are sufficient. Further, considering the time required for dissolution in a solvent, the ease of coating on an OPC support, and the like, those having an intrinsic viscosity of 2.0 or less are practical.

The polyester resin having such an intended intrinsic viscosity can be easily obtained by adjusting the melt polymerization conditions such as the molecular weight modifier, the polymerization time and the polymerization temperature and the conditions of the chain extension reaction in the subsequent step.

Further, this dicarboxylic acid or its ester-forming derivative is copolymerized with a cycloalkene-based special dihydroxy compound represented by 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane as a typical amorphous compound. In high quality polyester, the weight average molecular weight in terms of polystyrene is 100,000 (the intrinsic viscosity in chloroform is 0.6
dl / g) is the limit that can be easily obtained by a conventionally known polymerization method. When a polyester having an intrinsic viscosity higher than this is required, the method described below can be used.

In order to obtain a high molecular weight polyester resin having an intrinsic viscosity of 0.6 or more, a method of polymerizing by the above-mentioned method and then reacting with diisocyanate is preferable. By this post-treatment, the molecular chain of the polyester can be extended, the intrinsic viscosity in chloroform of 0.6 or more can be easily achieved, and mechanical properties such as abrasion can be improved.

The diisocyanate used in the present invention contains 2
All compounds in which two isocyanate groups are present in the same molecule are included. More specifically, for example, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, methylene-
4,4'-bisphenyl diisocyanate, xylylene diisocyanate, 3-isocyanatomethyl-3,
Examples thereof include 5,5-trimethylcyclohexyl isocyanate, and among them, methylene-4,4′-bisphenyl diisocyanate is preferable.

These may be used alone or in combination of two or more kinds.

The amount of diisocyanate to be reacted with the polyester resin is usually in the range of preferably 0.5 to 1.3 times, more preferably 0 times the number of moles of polyester calculated on the basis of the number average molecular weight. The range is from 0.8 to 1.1. Since the end of the polyester molecule is an alcoholic OH, diisocyanate reacts with the alcohol to form a urethane bond, whereby chain extension of the polyester is achieved. A urethane bond is introduced into the polyester in the subsequent step, but since the amount of the urethane bond is usually 1% or less in terms of mole fraction, the refractive index, birefringence, glass transition point, transparency, etc. of the resin as a whole are The physical properties are the same as the untreated polyester resin.

In the above chain extension reaction, a suitable catalyst may be used if necessary. The catalyst is preferably a metal catalyst such as tin octylate, dibutyltin dilaurate or lead naphthenate, diazobiscyclo [2.2.2] octane or tri-N-butylamine. Although the amount of the catalyst added depends on the chain extension reaction temperature, it is usually preferably 0.01 mol or less, more preferably 0.001 mol or less, relative to 1 mol of diisocyanate.

The reaction proceeds by adding an appropriate amount of the catalyst and diisocyanate to the above-mentioned polyester in a molten state and stirring the mixture while flowing dry nitrogen. If necessary, the reaction may be carried out in an appropriate organic solvent which is a good solvent for polyester and diisocyanate. At this time, the concentration of polyester must be maintained at a concentration required for intermolecular reaction. This concentration varies depending on the molecular weight of the polyester, but is usually 20% by weight or more, preferably 40% by weight or more. If the concentration is lower than the proper concentration, the intramolecular reaction may occur preferentially, and a so-called cyclic polymer may be formed. The organic solvent used is preferably a stable compound having a high boiling point as much as possible, and usually trichlorobenzene, dimethyl sulfoxide, N, N-dimethylformamide, xylene and the like are used.

The reaction temperature of the chain extension reaction varies depending on the conditions, but when it is carried out in an organic solvent, it may be set to a temperature not higher than the boiling point of the solvent, or to a temperature not lower than the glass transition point of the polyester when the organic solvent is not used. desirable. Since the molecular weight that can be reached and the degree of coloration due to side reactions are determined by the reaction temperature, consider the target molecular weight and the molecular weight of the polyester before the reaction, etc., and select an appropriate reaction system and an appropriate reaction temperature. be able to. For example,
When trichlorobenzene is used as the organic solvent, 13
The reaction is possible in the range of 0 ° C to 150 ° C, and there is almost no coloring due to side reaction.

Due to the chain extension reaction of the above-mentioned polyester, the molecular weight is greatly increased and the intrinsic viscosity is increased.
Although the final attainable molecular weight varies depending on the molecular weight before the reaction, usually, the molecular weight of the chain-extended polyester can be adjusted to a target value by changing the reaction temperature, the reaction time, and the amount of diisocyanate. Since it varies depending on the case, it cannot be specified in a lump. Generally, the higher the temperature and the longer the reaction time, the higher the molecular weight. Further, the amount of diisocyanate is the most equivalent to the number of moles of the polyester determined from the number average molecular weight, or per 1.1 equivalents, the effect of chain extension is the highest.

Usually, an amorphous polyester obtained by copolymerizing a dicarboxylic acid or its ester-forming derivative with a cycloalkane-based special dihydroxy compound represented by 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane. Has a molecular weight of about 50,000 (0.4d in intrinsic viscosity
1 / g), the maximum is about 100,000 (0.6d in intrinsic viscosity)
1 / g). For example, when the above chain extension reaction is carried out using about 50,000 polyesters that can be most easily produced as a raw material, a high molecular weight polyester having an intrinsic viscosity of 0.7 to 1.5 is obtained.

The chain-extended polyester generally has a broad molecular weight distribution. The molecular weight distribution of the amorphous polyester copolymerized with the above-mentioned special dihydroxy compound produced by melt polymerization is usually about 2 in terms of the ratio of the weight average molecular weight to the number average molecular weight, although it varies depending on various reaction conditions. After the chain extension reaction, it usually becomes about 4 or more. For applications in which a molecular weight distribution is not desirable, the molecular weight distribution can be controlled, if necessary, using a commonly known molecular weight fractionation method.

As the molecular weight fractionation method, a reprecipitation method with a poor solvent, a method of passing through a column packed with a gel and sieving according to the size of the molecule are known. For example, the molecular weight can be fractionated by dropping a poor solvent such as alcohol or acetone into a solution of a polar organic solvent such as chloroform or DMSO of the polyester resin of the present invention. in this case,
The high molecular weight polymer precipitates first. Further, by adding a poor solvent to the polymer solution of the present invention, and after cloudy precipitation, the temperature of the container is raised to redissolve the precipitate, and a method of obtaining a cloudy precipitate by cooling again to improve the accuracy of molecular weight fractionation. You can also The method of molecular weight fractionation is not limited to this, and for example, Analysis of polymer is possible.
S., T.S. R. Crompton, Pergam
The method described in on Press can also be used.

The polyester resin of the present invention produced by the above-mentioned method is a substantially linear polymer.

The above-mentioned polyester resin of the present invention is
It can be used as a binder for a single-layer type photoreceptor, a charge transport layer for a laminated type photoreceptor, or a binder for both layers of a charge transport layer and a charge generation layer.

The polyester resin of the present invention has a function-separated type photoreceptor, for example, a photoreceptor layer (2) is formed on a conductive support (1) as shown in FIGS. Used for structured photoconductors. That is, the photoreceptor layer (2) is composed of a single photoreceptor layer (2a) containing the binder resin of the present invention, a charge generation material and a charge transport material as shown in FIG. 1 (A). Layered photoreceptor,
As shown in FIG. 2A, a charge generation layer (2b) containing at least a charge generation material and a charge transport layer (2c) containing a charge transport material are sequentially laminated, or
As shown in FIG. 2B, a layered type photoconductor in which a charge transport layer (2c) and a charge generation layer (2b) are sequentially laminated, as opposed to FIG. 2A, FIG. 1B and FIG. 2 (C), a photoreceptor having a surface protective film (2d) formed on the surface of the single-layer photoreceptor or the laminated photoreceptor, and further,
As shown in FIG. 3, it can be applied to a photoreceptor or the like in which a charge transport layer (2c) and the single photoreceptor layer (2a) are sequentially laminated. It is not always necessary to use the binder resin of the present invention for the charge generation layer (2b), and for example, the charge generation material (2b) may be formed by vapor deposition, sputtering or the like. Further, an intermediate layer may be formed between the conductive support (1) and the photoconductor layer (2).

When the polyester resin for a binder of the present invention is applied to the above-mentioned photoreceptor, it may be contained in at least the photoreceptor layer (2) and may be used in combination with other binder materials. In this case, other binder materials can be used in a timely manner as long as necessary conditions such as abrasion resistance of the photoreceptor and solubility with the dye are not impaired, and usually 50% by weight or less is used.

As the above-mentioned other binder materials, known polymer compounds such as styrene-based copolymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylics are used. Polymer, styrene-acrylic copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinyl chloride-vinyl acetate copolymer, known polyester other than the present invention,
Thermoplastic resin such as alkyd resin, polyamide, polyurethane, epoxy resin, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl butyrate resin, polyether resin, phenol resin, epoxy acrylate, urethane acrylate Examples include heat-curable resins such as resins and photocurable resins. Of course, not limited to the above examples, all resins generally used as a binder material can be used. In addition, poly-
A photoconductive polymer such as N-vinylcarbazole can also be used as the above-mentioned other binder material.

Examples of the charge generating material include selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo compounds, bisazo compounds, trisazo compounds,
Dibenzpyrenequinone compound, phthalocyanine compound, indigoid compound, triphenylmethane compound, slene compound, toluidine compound, pyrazolone compound, perylene compound, perinone compound, quinacridone compound, polycyclic quinoline compound , Pyrylium compounds, and the like. Of course, the compound is not limited to these compounds, and any compound that can be used as a known charge generating material is used. These are optional
You may use it in mixture of 2 or more types.

Examples of the above charge transport material include chloranil, tetracyanoethylene, fluorenone compounds such as 2,4,7-trinitro-9-fluorenone, 2,
Nitro compounds such as 4,8, -trinitrothixanthone and dinitroanthracene, amine compounds such as 4-methoxy-triphenylamine, N, N-diethylaminobenzaldehyde, N, N-diphenylhydrazone and N-methyl-3-carba Hydrazone compounds such as zolylaldehyde and N, N-diphenylhydrazone, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, 1- (1-phenyl-4-carbazolyl) methylideneamino-1,2,3,3. Carbazole compounds such as 4, -tetrahydroquinoline and N-methylcarbazole, 1
-Phenyl-3- (4-dimethylaminophenyl) pyrazoline, 1-phenyl-3- (4-dimethylaminostyryl) -5- (4-dimethylaminophenyl) pyrazoline and 1-phenyl-3- (4-diethylaminostyryl) ) -5- (4-Diethylaminophenyl) pyrazoline and other pyrazoline compounds, 2- (4-diethylaminophenyl) -4- (4-dimethylaminophenyl) -5-
Oxazole compounds such as (2-chlorophenyl) oxazole, 2,5-di (4-N, N-dimethylaminophenyl) -1,3,4-oxadiazole and 2,5-di (4-N, N) -Diethylaminophenyl) -1,3,4
-Oxadiazole compounds such as oxadiazole, isoxazole compounds, thiazole compounds such as 2- (4-diethylaminostyryl) -6-diethylaminobenzothiazole, thiadiazole compounds, imidazole compounds, pyrazole compounds, indole -Based compounds, triazole-based compounds, stilbene-based compounds, triphenylmethane-based compounds and other nitrogen-containing cyclic compounds and condensed polycyclic compounds, and further poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, ethylcarbazole-formaldehyde Resin etc. are mentioned. Needless to say, the present invention is not limited to the above examples, and any compound that can be used as a charge transport material for OPC can be applied to the present invention.
Further, these charge transport materials can be used as a mixture of two or more kinds.

As the material of the conductive support shown in FIG. 1A, for example, a metal sheet of aluminum, nickel, copper, zinc, palladium, silver, indium, stainless steel or the like can be used, but the material is not limited thereto. Instead of this, for example, a conductive layer may be provided on an insulating base such as polyethylene terephthalate to form the support.

The use ratio of the polyester binder of the present invention, the charge generating material and the charge transporting material in the photoreceptor having the single layer type photoreceptor layer (2) is appropriately selected according to the intended photoreceptor. However, in order to keep the sensitivity of the photoconductor sufficiently, prevent the surface potential from lowering, and keep the wear resistance of the photoconductor good, the charge generating material is usually added to 100 parts by weight of the binder. 2 to 25 parts by weight, charge transport material 25
The range of 150 to 150 parts by weight is preferable. The thickness of the single-layer type photoreceptor layer (2) is appropriately determined depending on the purpose, but is usually preferably in the range of 3 to 50 μm.

As the method for forming the charge generating layer (2b) in the laminated type photoreceptor layer (2), the charge generating material is vacuum-deposited, or the charge generating material is formed by using an appropriate binder resin. There is a method of forming a binder. When the charge generating layer (2b) is formed using a binder resin containing the polyester resin of the present invention, the binder resin may be 0 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. preferable. The greater the weight of the binder resin or the like, the greater the adhesion of the conductive substrate to the support. The above-mentioned charge generation layer may have an appropriate thickness depending on the purpose, but it is preferably in the range of usually 0.1 to 5 μm.

Further, when the charge transport layer (2c) in the laminated type photoreceptor layer (2) is formed by using a binder resin containing the polyester resin of the present invention, 100 parts by weight of the charge transport material is used. On the other hand, the amount of the binder resin is preferably 25 to 500 parts by weight. When the weight of the binder resin or the like is 25 parts by weight or more, the strength of the charge transport layer is improved, which is preferable, and when it is 500 parts by weight or less, the charge transport ability is improved, which is preferable. The above-mentioned charge generation layer may have an appropriate thickness depending on the purpose, but it is usually preferable to be in the range of 2 to 100 μm.

[0065]

EXAMPLES The present invention will be described below based on specific examples.

1. Intrinsic Viscosity After dissolving 0.15 to 0.5 g of the copolymer in chloroform, the intrinsic viscosity was determined at 20 ° C. by an ordinary method using an Ubbelohde viscometer.

2. Molecular weight Toyo Soda column G3000H, 7.5 x 60 cm
The elution volume of the sample was measured at 35 ° C. using chloroform as the solvent. The number average molecular weight and the weight average molecular weight were determined from a calibration curve prepared using standard polystyrene.

3. Electrophotographic characteristics It was measured using an "electrometer" manufactured by Kawaguchi Denki Seisakusho. That is, the exposure amount E required to halve the receptive potential Va (V) when the surface of the photoconductor is charged at a charging potential of -6 KV for 5 seconds and the potential Vi (V) after dark decay for 5 seconds. (Lux.sec) was examined.

4. Abrasion resistance: 1 cm ² for a photoconductor formed on an aluminum drum
10c per 10g on PPC paper
The amount of wear was measured by sliding for 1 hour at a speed of m / sec.

Examples 1-2 terephthalic acid dimethyl ester 55 mol, 10.6
8 kg, 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane 38.5 mol, 1
3.71 kg, ethylene glycol 116 mol,
With 7.2 kg as raw material, calcium acetate as a catalyst
0.091 mol and 15.99 g were used, and these were put into a reaction tank and stirred at 190 ° C. to 2 ° C. according to a conventional method.
The transesterification reaction was performed by gradually heating to 30 ° C. After extracting a predetermined amount of methanol out of the system, 0.066 mol of germanium oxide as a polymerization catalyst, 6.9 g,
To prevent coloration, phosphoric acid trimethyl ester 0.
1 mol and 14 g are added, the temperature is raised and the pressure is gradually reduced, and the temperature of the heating tank is set to 290 ° C. and the degree of vacuum is set to 1 Torr or less while removing the generated ethylene glycol. This condition was maintained, the increase in viscosity was waited, the reaction was terminated after reaching a predetermined stirring torque (after about 3 hours), and the reaction product was extruded into water to obtain pellets. This polyester resin of the present invention is referred to as polyester binder 1 (Example 1).

The intrinsic viscosity of this polyester binder 1 was 0.55. The weight average molecular weight determined by GPC was 81,000, and the number average molecular weight was 36,000.
It was 0. The glass transition temperature was 115 ° C.

30 g of the above polyester resin was dissolved in trichlorobenzene to prepare a 40% by weight solution. To the above solution, 0.337 g of methylenebis (4-phenylisocyanate) and 0.175 mg of diazobiscyclo [2.2.2] octane, 1.1 times the number of moles of the polyester copolymer calculated from the number average molecular weight, were added. In addition, 150 ℃
The mixture was heated and stirred under a nitrogen stream for 10 hours. The obtained reaction product was reprecipitated in methanol and washed with a large amount of methanol and distilled water to obtain a chain-extended polyester resin (polyester binder 2) of the present invention (Example 2).

The intrinsic viscosity of the above polyester binder 2 was 0.86 dl / g, the weight average molecular weight determined by GPC was 150,000, and the number average molecular weight was 4.
It was 8,000. The glass transition temperature was 115 ° C.

Next, 20 g of the bisazo compound represented by the structural formula (6) was pulverized and mixed with 1 liter of dichloromethane by a ball mill, and an aluminum drum was dipped in the obtained dispersion liquid to coat the surface of the drum with the solution. Next, the drum was thoroughly dried to evaporate the solvent, thereby forming a charge generation layer having a thickness of 0.3 μm.

[0075]

Embedded image

Next, 100 g of the styryl compound represented by the structural formula (7) and 200 g of polyester binder 1 were dissolved in 1 liter of dichloromethane, and the drum on which the charge generating layer had been formed was immersed in the solution, and the charge generating layer was formed. Was newly coated with the solution. This was dried at 80 ° C. for about 1 hour to form a charge transport layer having a thickness of 20 μm. This photosensitive drum is referred to as a sample OPC1.

[0077]

[Chemical 9]

A sample OPC2 was prepared under the same conditions except that the polyester binder 2 was used in place of the polyester binder 1.

Comparative Example 1 A photoconductor drum was prepared in the same manner as in Example 1 except that bisphenol A type polycarbonate was used instead of the “polyester binder 1” in Example 1, and this was designated as sample OPC3.

The electrophotographic characteristics and the wear amount of the above-mentioned samples OPC1 to OPC3 were measured. The results are shown in Table 1.
Shown in

[0081]

[Table 1]

Examples 3 to 9 and Comparative Example 2 In the same manner as in Example 1, a sample resin having the composition shown in Table 2 was prepared, and then a photosensitive drum was prepared. Table 2 shows the results of measuring the amounts of wear of these Examples 3 to 9 and Comparative Example 2. In the table, examples using the chain extension reaction are indicated by a circle.

[0083]

[Table 2]

From the above results, the polyester of the present invention, which is copolymerized with a special dihydroxy compound represented by 1,1-bis [4- (2-hydroxyethoxy) phenyl] cyclohexane as a typical example, is suitable as a binder for OPC. It is clear.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a single-layer type photoconductor.

FIG. 2 is a diagram showing a structure of a laminated type photoreceptor in which a charge generation layer (2b) and a charge transport layer (2c) are laminated.

FIG. 3 is a diagram showing a structure of a laminated photoreceptor in which a single photoreceptor layer (2a) and a charge transport layer (2c) are laminated.

[Explanation of symbols]

 1 Conductive Support 2 Photoreceptor Layer 2a Single Photoreceptor Layer 2b Charge Generation Layer 2c Charge Transport Layer 2d Surface Protective Film

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Michiaki Fuji, 5-2, Higashi-Toyonaka-cho, Toyonaka-city, Osaka, 103-105 (72) Inventor Yukio Horikawa 1-27-12-1 Shigaki, Matsubara, Osaka

Claims (1)

[Claims] 1. A polyester resin polymerized from a dicarboxylic acid or an ester-forming derivative thereof and a diol, wherein the diol is 10 based on the total diol component of 100.
General formula (1) of mol% or more (R ₁ is an alkylene group having 2 to 4 carbon atoms, R ₂ , R ₃ ,
R ₄ and R ₅ are hydrogen or an alkyl group having 1 to 4 carbon atoms, an aryl group or an aralkyl group and may be the same or different, and R ′ is an alkyl group having 1 to 4 carbon atoms. n is an integer of 2 or more, m is an integer of 0 or more and 2 (n + 2) or less. ) A polyester resin for a binder for an electrophotographic photoreceptor, which comprises a dihydroxy compound represented by