JP2546739B2 - Photoconductive polymer compound - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a photoconductive polymer compound, and more particularly, to a photoconductive polymer compound suitable for a carrier transport material such as an electrophotographic photoreceptor and an electroluminescent device. .

[Prior Art] Conventionally, various compounds have been used as a photoconductive compound. For example, in an electrophotographic photoreceptor, an inorganic photoreceptor containing an inorganic photoconductive compound as a main component has been widely used. However, these are not always satisfactory in sensitivity, thermal stability, moisture resistance, durability and the like.

In recent years, research and development of organic photoconductors containing various organic photoconductive compounds as main components have been actively conducted in order to overcome the disadvantages of inorganic photoconductors.

Such organic photoreceptors can be incinerated and have no pollution, and many of them can be formed into a thin film by coating and are easily mass-produced. Therefore, it has the advantages that the cost can be greatly reduced and that it can be processed into various shapes depending on the application. However, the sensitivity and durability of the organic photoreceptor still have problems, and the appearance of an organic photoreceptor having high sensitivity and high durability has been strongly desired. In order to improve such a point, an attempt has been made to develop a higher performance organic photoreceptor by assigning a carrier generation function and a carrier transport function to different substances, respectively. There are two types of photoconductors of such a so-called function-separated type, a single-layer type and a laminated type. Both types can be selected from a wide range of materials, and photoconductors with arbitrary performance can be compared. Much research has been done because they can be easily created. In such a function-separated type photoreceptor, as the carrier transporting material used in the carrier transporting layer, a compound having a high charge injection efficiency from the carrier generating layer and a large charge mobility in the carrier transporting layer is used. You have to choose. For this purpose, a compound having a low ionization potential and a compound that easily generates a radical cation are selected. Among them, a triarylamine derivative (JP-A-53-47260) and a hydrazone derivative (JP-A-57-101844) Oxadiazole derivatives (JP-B-34-5466), hirazoline derivatives (JP-B-52-4188), and stilbene derivatives (JP-A-5-5188).
No. 8-198043), triphenylmethane derivative
Low molecular weight compounds such as those disclosed in JP-A-45-555) have been conventionally used.

Such carrier transport layers often comprise a low molecular compound as described above dispersed or dissolved in a polymeric film forming binder such as polycarbonate, polyester, and the like. Generally, the polymeric film-forming binder in the transport layer is itself electrically inactive and becomes electrically active when it contains a carrier transport material.

[Problems to be Solved by the Invention] However, the addition of the low-molecular compound as described above significantly lowers the glass transition temperature of the polymer system, and causes mechanical damage such as damage to the photosensitive layer and deformation of the photosensitive member itself in various electrophotographic processes. Not only does this cause a decrease in strength, but when the amount of the low-molecular compound is increased for the purpose of improving the charge transport performance, precipitation of the low-molecular compound by crystallization in the polymer, phase separation, etc. are caused. As a result, there is a further problem that the mechanical strength and sensitivity of the photoreceptor are reduced.

Accordingly, an object of the present invention is to provide a photoconductive polymer compound that can impart excellent mechanical strength and photoconductivity to a photoreceptor or the like without causing crystal precipitation or phase separation.

[Means for Solving the Problems] In view of the above problems, the present inventors have conducted intensive studies and as a result, have found that the above object of the present invention is at least one of the following structural units (I), (II) and (III) Has been found to be achieved by providing a polymer compound having at least one type of repeating unit containing

[Wherein, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each represent an alkyl group or an alkoxy group, and n ₁ and n ₃ each represent an integer of 1 to 5,
n ₂ , n ₄ and n ₅ each represent an integer of 1 to 4. Also, l, m
And p each represent a number greater than 0 and 1 or less. Hereinafter, the present invention will be described in more detail.

The polymer compound of the present invention comprises the above structural units (I) and (I)
It has at least one kind of repeating unit containing at least one of I) and (III), and a homopolymer composed of a single repeating unit also has the above-mentioned structural units (I) to (I).
Copolymers containing at least one of (III) and comprising two or more types of repeating units different from each other can be preferably included in the present invention. Furthermore, copolymers of these repeating units and other polymerizable monomers are also included. These include those having a two-dimensional or three-dimensional network structure.

As the polymer compound of the present invention, those containing the structural unit (II) are preferably used.

In the polymer compound of the present invention, the above structural units (I) to (I)
It is preferable that at least one of (III) is contained in 50 to 100 mol%.

Further, the polymer compound of the present invention preferably has a number average molecular weight of 3,000 to 3,000,000, and more preferably 10,000 to 1,000,000, in terms of molecular weight.

In the present invention, in each of the structural units (I) to (III), any of the three phenyl groups bonded to the N atom can have any of the substituents R _{1 to} R ₅ . Examples of such a substituent include an alkyl group such as a methyl group and an alkoxy group such as a methoxy group. Also, n ₁ R ₁ ,
n ₂ R ₂ , n ₃ R ₃ , n ₄ R ₄ and n ₅ R ₅ may be the same or different.

The polymer compound of the present invention further includes a copolymer with another polymerizable monomer as described above. Examples of such a polymerizable monomer include methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Examples include methacrylate monomers, acrylate monomers such as methyl acrylate and butyl acrylate, styrene monomers, and acrylonitrile.

As the polymer compound of the present invention, those containing the structural unit (I) and methyl methacrylate preferably in a ratio of 1: 1 are preferably used.

 Hereinafter, specific examples of the polymer compound of the present invention will be described.

The synthesis examples of the polymer compound of the present invention are described below, but other polymer compounds of the present invention can also be synthesized according to these synthesis examples.

Synthesis Example 1: Synthesis of Polymer Compound (2-1) of the Present Invention 2 g (7.7 mmol) of 4-hydroxytriphenylamine was placed in a 100 ml four-necked flask, and 40 ml of dehydrated DMF was added and dissolved. 0.37 g (7.7 mmol) of sodium hydride was added and the mixture was stirred until there was no solid matter. The reaction vessel was transferred to an ice bath, cooled to 5 ° C., and chloromethylstyrene was added.
18 g (7.7 mmol) were added dropwise. After reacting at 5 ° C. for 2 hours, the reaction was carried out at room temperature overnight. The reaction solution was poured into 200 ml of deionized water and extracted with toluene. The toluene solution is
Washing was performed with ion-exchanged water until the aqueous layer became neutral. The reddish brown oily substance obtained by removing toluene under reduced pressure was dissolved in a mixed solvent of toluene / hexane = 2/1 and purified using silica gel. Removal of the solvent gave a yellow oil. (2 g, 70% yield) Polymerization of methylstyryl 4- (N, N-diphenylamino) -phenyl ether 11.72 g (0.031 mol), methyl methacrylate 3.11 g (0.031 mol), AIBN 0.31 g (0.0019 mol) The mixture was placed in an ampoule for use, adjusted to 50 ml with toluene, degassed, and sealed. Polymerization was performed at a polymerization temperature of 60 ° C. and a reaction time of 2 hours. Immediately after the polymerization was completed, the ampoule was cooled in cold water, opened, chloroform was added, and the solution was added dropwise to a 20-fold amount of methanol. Reprecipitation was performed twice to obtain the desired product. (Dry weight
(3.1 g, yield: 20.9%) The proportion of triphenylamine in the obtained polymer was 75% by weight. The molecular weight was 1 × 10 ⁵ .

Synthesis Example 2: Synthesis of polymer compound (3-1) of the present invention 10 g of 4,4'-dihydroxytriphenylamine (0.036
Mol) dissolved in 300 ml of DMSO and sodium hydride (50%
(Mmol) was added and stirred. The reaction vessel was cooled to 5 ° C. and chloromethylstyrene 11.95 g (0.079 mol)
Was added dropwise. After reacting at 5 ° C. for 2 hours, the reaction was carried out at room temperature overnight. The reaction solution was poured into 200 ml of deionized water, and the oil was extracted with toluene. The reddish-brown oil component obtained by removing toluene was purified using a toluene / hexane = 2/1 solvent to obtain a target monomer. (Yield 12.8 g, 70% yield) Bis {(methylstyryl) 4- (N, N-diphenylamino)} phenyl ether 10 g (0.02 mol), AIBN 0.2 g
(0.0012 mol) was placed in an ampoule, made up to 50 ml with toluene, degassed, and sealed.

Polymerization was carried out in the same manner as in Synthesis Example 1 to obtain the desired product.
(Yield 2.0 g, yield 20%) The ratio of triphenylamine in the obtained polymer was 47.7% by weight, and the molecular weight was 2 × 10 ⁵ .

Synthesis Example 3: Synthesis of polymer compound (5-1) of the present invention 5 g of 4,4 ', 4 "-trihydroxytriphenylamine
(0.017 mol) in a 100 ml four-necked flask
MF (40 ml) was added and dissolved. 1.47 g of sodium hydride (0.0
61 mol) and stirred. The reactor was cooled to 5 ° C., 9.37 g (0.061 mol) of chloromethylstyrene was added dropwise, and the mixture was reacted for 2 hours and then reacted at room temperature overnight.

The reaction solution was poured into 200 ml of ion-exchanged water and extracted with toluene. The toluene solution was washed with water to remove toluene. The oily substance was purified to obtain the target monomer. (Yield 60
%) 5 g of the obtained monomer (7.8 × 10 ^-3 mol) and 3.05 g of AIBN
(0.019 mol) was dissolved in a toluene solution and partially reacted. 3 g of the obtained polymer was dissolved in toluene, and AIBN0.
92 g was added and spin-coated on a glass substrate provided with an Al electrode to form a film. This film was heated to obtain a three-dimensional polymer.

The polymer compound of the present invention is preferably used as a carrier transporting substance in an electrophotographic photoreceptor, an electroluminescent device and the like. As the electrophotographic photoreceptor, various conventionally known photoreceptors can be mentioned, and any of them can be applied. That is, the present invention is applicable to any of various inorganic or organic photoconductors, and a single-layer or stacked-layer photoconductor of a function-separated type. In particular, as the carrier-generating substance that can be used in combination with the polymer compound of the present invention, any of inorganic pigments and organic pigments can be used as long as they can generate free carriers by absorbing electromagnetic waves.

Examples of such a carrier generating substance (CGM) include the following.

(1) Amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, cadmium sulfate selenide, mercury sulfide, lead sulfide, zinc oxide, titanium oxide amorphous silicon, etc. Inorganic pigments (2) Azo pigments such as monoazo pigments, polyazo pigments, metal complex azo pigments, pyrazolone azo pigments, stilbene azo and thiazole azo pigments (3) anthraquinone derivatives, anthantrone derivatives, dibenzopyrenequinone derivatives, pyranthrone derivatives, Anthraquinone or polycyclic quinone pigments such as biolanthrone derivatives and isobiolanthrone derivatives (4) Indigo pigments such as indigo derivatives and thioindigo derivatives (5) Various metal phthalocyanines such as titanyl phthalocyanine and vanadyl phthalocyanine; Type, γ
-Type, τ-type, τ'-type, η-type, η'-type and other non-metallic phthalocyanine-based pigments such as phthalocyanine (6) Carbonium-based pigments such as diphenylmethane-based pigments, triphenylmethane pigments, xanthene pigments and acridine pigments (7) Quinone imine pigments such as azine pigments, oxazine pigments and thiazine pigments (8) Methine pigments such as cyanine pigments and azomethine pigments (9) Quinoline pigments (10) Nitro pigments (11) Nitroso pigments (12) Benzoquinone and naphthoquinone Pigments (13) Naphthalimide pigments (14) Perinone pigments such as bisbenzimidazole derivatives (15) Fluorenone pigments (16) Squarylium pigments (17) Azurenium compounds Further preferred examples of azo compounds and polycyclic quinone pigments It shows about. For specific examples of these compounds, see
-298013 and the like.

(I-5) A-N = N-Ar 1 -CH = CH-Ar 2 -N = N-A (I-6) A-N = N-Ar 1 -CH = CH-Ar 2 -CH = CH -Ar ³ -N = N
-A (I-8) A-N = N-Ar 1 -N = N-Ar 2 -N = N-A (I-9) A-N = N-Ar 1 -N = N-Ar 2 -N = N -Ar ³ -N = N
-A [However, in the above general formulas, Ar ¹ , Ar ² and Ar ³ : a substituted or unsubstituted carbocyclic aromatic ring group, respectively, R ¹ , R ² , R ³ and R ⁴ : an electron withdrawing property A group or a hydrogen atom, wherein at least one of R ^{1 to} R ⁴ is an electron-withdrawing group such as a cyano group; (X is a hydroxy group, Or —NHSO ₂ —R ⁸ (where R ⁶ and R ⁷ are each a hydrogen atom or a substituted or unsubstituted alkyl group, R ⁸ is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group), Y Is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxyl group, a sulfo group, a substituted or unsubstituted carbamoyl group or a substituted or unsubstituted sulfamoyl group (provided that when m is 2 or more, And Z may be different groups from each other.), Z is an atomic group necessary for forming a substituted or unsubstituted carbocyclic aromatic ring or a substituted or unsubstituted heterocyclic aromatic ring, and R ⁵ is A hydrogen atom, a substituted or unsubstituted amino group, a substituted or unsubstituted carbamoyl group, a carboxyl group or its ester group, and Ar ⁴ is a substituted or unsubstituted aryl group. Group, n is 1
Or an integer of 2, and m is an integer of 0 to 4. )] Further, polycyclic quinone pigments of the following general formula [II] group can also be used as CGM.

General formula [II]: (However, in this general formula, X ′ represents a halogen atom, a nitro group, a cyano group, an acyl group or a carboxyl group;
p represents an integer of 0 to 4, and q represents an integer of 0 to 6. The squarylium pigment is described in JP-A-60-258550.

Japanese Patent Application No. 62-241983 for titanyl phthalocyanine
There is a description in the specification.

The azurenium compound is described in Japanese Patent Application No. 62-251188.

Furthermore, regarding special metal-free phthalocyanine,
It is described in the specification of 61-295784 and the like.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 The polymer compound (2-1) of the present invention synthesized in Synthesis Example 1
Was prepared as follows.

An aluminum electrode was deposited on a glass substrate. Selenium was deposited thereon to form a carrier generation layer.

A solution prepared by dissolving 0.5 g of the polymer compound (2-1) of the present invention in 5 ml of 1,2-dichloromethane was applied to a thickness of about 8 μm using a spin coater to form a carrier transport layer.

Further, an aluminum electrode was vapor-deposited thereon to obtain a sample for measuring mobility and wear resistance.

The mobility was measured using a commonly used TOF direction (time of flight method).

The abrasion resistance test was performed using a Taber-type abrasion tester with a wear wheel CS-10 and a load of 500 gf.

Further, the degree of precipitation in the carrier transport layer was visually evaluated.

 Table 1 shows the results.

Example 2 Polymer compound of the present invention (3-1) synthesized in Synthesis Example 2
A sample for measuring mobility and abrasion resistance was prepared in the same manner as in Example 1 except that the carrier transport layer was formed using a solution in which 0.2 g was dissolved in 1,2-dichloroethane in 2 g. evaluated.

 Table 1 shows the results.

Example 3 Polymer compound of the present invention (5-1) synthesized in Synthesis Example 3
, A carrier transport layer was formed, and Se was vapor-deposited on the sample, and Al was vapor-deposited thereon to form a carrier-generating layer. Was prepared and evaluated in the same manner. Table 1 shows the results.

Comparative Example 1 A solution in which 0.5 g of triphenylamine and 1 g of Dianal BR-80 (manufactured by Mitsubishi Rayon Co., Ltd., acrylic resin) were dissolved in 10 ml of 1,2-dichloroethane was used as a coating solution for forming a carrier transport layer. A sample for measuring the mobility and abrasion resistance was prepared in the same manner as in Example 1 except that was formed, and evaluated in the same manner. Table 1 shows the results.

Comparative Example 2 Polyvinylcarbazole (Tubicol 21 manufactured by Anan Koran Co., Ltd.)
A solution prepared by dissolving 0.2 g in 5 ml of 1,2-dichloroethane as a coating solution for forming a carrier transport layer was used for the measurement of mobility and abrasion resistance in the same manner as in Example 1 except that the carrier transport layer was formed. A sample was prepared and evaluated similarly. Table 1 shows the results.

Example 4 The polymer compound (1-1) of the present invention has a molecular weight of 2 ×
Except for using 10 ⁴ ones in the same manner as in Example 1 to prepare a mobility and abrasion resistance measurement sample was evaluated in the same manner. Table 1 shows the results.

Example 5 The polymer compound (1-1) of the present invention has a molecular weight of 5 ×.
Except for using 10 ⁶ intended to produce a mobility and abrasion resistance measurement sample in the same manner as in Example 1, was evaluated in the same manner. Table 1 shows the results.

As is clear from Table 1, all of Examples 1 to 5 using the polymer compound of the present invention were superior to Comparative Examples 1 and 2 using a carrier transporting substance outside the present invention in mobility. , Has wear resistance and precipitation properties.

[Effects of the Invention] As described in detail above, the polymer compound of the present invention can impart excellent mechanical strength and photoconductivity to a photoreceptor or the like without causing crystal precipitation or phase separation. .

Claims (1)

(57) [Claims] 1. The following structural units (I), (II) and (III)
A polymer compound having at least one kind of repeating unit containing at least one of the following. [Wherein, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ each represent an alkyl group or an alkoxy group, and n ₁ and n ₃ each represent an integer of 1 to 5,
n ₂ , n ₄ and n ₅ each represent an integer of 1 to 4. Also, l, m
And p each represent a number greater than 0 and 1 or less. ]