JPH03109406A - Crosslinked polystyrene-based compound having hydrazone group in side chain, production thereof and electrophotographic sensitive unit using the same - Google Patents

Abstract

PURPOSE:To obtain the subject new polymer, useful as a charge-transfer material having high mobility and excellent in mechanical strength by reacting a styrene-based copolymer having a specific structure with a specified diisocyanate compound. CONSTITUTION:The objective polymer, obtained by reacting a styrene-based copolymer composed of units expressed by formulas I and II (R<1> is H, 1-4C alkyl, alkoxyl, etc.) with a diisocyanate compound (e.g. 1,3-benzene diisocyanate) expressed by formula III (R<2> is H or 1-4C alkyl) and having units expressed by formulas I and IV. Furthermore, the copolymer having the units expressed by formulas I and II is obtained by protecting, e.g. aldehyde group of 4- formylstyrene prepared by a well-known method, then copolymerizing the resultant compound with 4-vinylbenzyl alcohol, subsequently removing the protecting groups of the aforementioned copolymer by hydrolysis and then condensing the prepared compound with a 1,1-diarylhydrazine compound.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a novel crosslinked polystyrene compound having a hydrazone group in its side chain, a method for producing the same, and an electrophotographic photoreceptor using the same. In an electrophotographic photoreceptor using a charge generation material and a charge transfer material,
The present invention relates to a crosslinked polystyrene compound having a hydrazone group that has an excellent function as a charge transfer material and has excellent mechanical strength due to crosslinking, a method for producing the same, and an electrophotographic photoreceptor using the same as a charge transfer material. .

[Prior art and its problems] Conventionally, selenium (Se) and cadmium sulfide (CdS) have been used as photoconductive materials for photoreceptors used in electrophotography.
), zinc oxide (ZnO), and 7-E/L/fasilicon (a-3i).

Although these inorganic photoreceptors have many advantages, they also have various disadvantages, such as being harmful and being expensive. Therefore, in recent years, many organic photoreceptors using organic materials that do not have these drawbacks have been proposed and put into practical use.

The structure of these photoreceptors includes a material that generates charge carriers (hereinafter referred to as charge generation material) and a material that receives and moves the generated charge carriers (hereinafter referred to as charge generation material).
There are two types of photoreceptors: a multilayer structure with a functionally separated photoreceptor in which charge transfer materials (called charge transfer materials) are formed in separate layers, and a single layer structure with a single-layer photoreceptor in which charge carrier generation and charge transfer are performed using the same material. However, multilayer structures are more widely used because they offer a wider range of material selection and higher sensitivity.

In recent years, with the development of non-impact printing technology, research and development of electrophotographic printers using laser light sources have been actively conducted. In these devices, as the device size becomes smaller and the speed increases, it is desired that the photosensitive materials have higher sensitivity in charge generation materials and higher mobility in charge transfer materials.

In the case of charge transfer materials, it is known that the mobility greatly depends on the concentration of the transfer material (e.g., triphenylamine compounds) in the binder (e.g., polycarbonate) (Takahashi, Gobayashi, Yokouchi, Electrophotography). , 25.
16 (1986)). If the concentration of the mobile material is increased, the mobility will increase, but the physical properties will deteriorate, such as cracking. Mechanical wear increases as paper passes through rough printing. Therefore, it is difficult to add charge transport materials in binders at high concentrations.

The present invention has been made in view of the conventional circumstances as described above, and has excellent mechanical properties that do not cause cracking even when used at high concentrations and have high mobility. The object of the present invention is to provide a novel compound useful as a charge transfer material, a method for producing the same, and an electrophotographic photoreceptor using the same.

[Means for Solving the Problem] As a result of continuing research in view of the conventional situation, the present inventors have found that by crosslinking a polymer having a charge transfer material in its side chain, the charge transfer material can be highly It has been found that a substance can be obtained that has excellent mechanical properties at different concentrations and exhibits high mobility, making it ideal as a charge transfer material for electrophotographic photoreceptors.

Specifically, the present invention provides a structural unit represented by the general formula [■]; (wherein R1 represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, an alkoxyl group, or a dialkylamino group); [■]: (In the formula, R2 represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms) A crosslinked polystyrene compound having a hydrazone group in its side chain, characterized by consisting of a structural unit represented by the following: It is.

In addition, the manufacturing method includes a structural unit represented by the general formula [E]; (wherein R1 represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, an alkoxyl group, or a dialkylamino group) A styrenic copolymer consisting of a structural unit represented by the formula [■]; and the general formula [IV]: GO (wherein, R2 represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms). It is characterized by reacting with the diisocyanate compound shown below.

Further, according to the present invention, there is provided an electrophotographic photoreceptor containing the above-mentioned crosslinked polystyrene compound having a hydrazone group in a side chain as a charge transfer material.

The crosslinked polystyrene compound having a hydrazone group in its side chain according to the present invention can be produced, for example, as follows.

That is, the first method is to first prepare a Grignard reagent of 4-chlorostyrene, and then add dimethylformamide (
DMF) is added to produce 4-formylstyrene (
W, J, Dale, L, 5tarrand
c,w,5trObel,J,Org,
chem, 2B, 1965°2225). Next, after protecting the aldehyde group of 4-formylstyrene as an acetal, the compound and 4-vinylbenzyl alcohol are copolymerized in the presence of a suitable polymerization initiator, and then hydrolyzed in an acidic solution to form an acetal. By removing the group and carrying out a condensation reaction with a desired 1゜1-diarylhydrazine compound, the general formulas [I] and [I[I]
A styrenic copolymer consisting of the structural unit shown is synthesized. Next, the crosslinked polystyrene compound of the present invention can be obtained by reacting this copolymer with the diisocyanate compound represented by the general formula [IV].

In the second method, 4-formylstyrene is produced in the same manner as above, and then a desired 1,1-diarylhydrazine compound is added to the 4-formylstyrene and condensed in the presence of an acidic catalyst. A styrene compound containing a hydrazone group is produced. Copolymerizing this monomer and 4-vinylbenzyl alcohol in the presence of a suitable polymerization initiator,
The crosslinked polystyrene compound of the present invention can also be obtained by reacting this copolymer with the diisocyanate-1-compound represented by the general formula [IV].

In the present invention, the copolymers represented by the general formula [I] and the formula [■] are easily soluble in solvents such as chloroform and methylene chloride, and are insoluble in methanol and ethanol.

The electrophotographic photoreceptor of the present invention has a structure in which an electrophotographic photosensitive layer is functionally separated into a charge generation layer and a charge transfer layer on a conductive substrate. Note that it is desirable that a base layer be formed between the conductive substrate and the electrophotographic photosensitive layer.

The conductive substrate used in the present invention includes aluminum,
Plastic films provided with a thin layer of nickel, chromium, etc., and paper or plastic films coated with or impregnated with a conductive substance are used.

For the charge transfer layer, a crosslinked polystyrene compound having a hydrazone group in a side chain according to the present invention is used. In the production of this charge transport layer, first, the general formula [I] and the formula [I[
Add the desired diisocyanate compound [IV] to a solution in which the copolymer shown in 1] is dissolved in a solvent such as methylene chloride or chloroform, cast this solution before the reaction occurs, and then crosslink by baking. A hard, solvent-insoluble film can be produced by this method.

This crosslinking reaction is an addition reaction, and impurities are difficult to generate. In addition, no cracks were observed even after the reaction.
It is extremely useful as a charge transfer material for electrophotographic photoreceptors.

The charge transfer layer of the electrophotographic photoreceptor has a crosslinking degree of 10%.
, a film thickness of 10 to 25 is preferred.

The charge generating layer includes a charge generating material, a binder and a solvent. Among these, examples of charge-generating materials include Se.
, CdS, ZnO, or other inorganic materials, or Cu, A! ,
Phthalocyanines having metal atoms such as In, Ti, Pb, and V, as well as inorganic phthalocyanines, azo pigments, and bisazo pigments.

Alternatively, organic materials such as cyanine pigments can be used alone or in combination. The ratio of the charge generation material contained in the charge generation layer is 0.05 to 0.05 to the charge generation layer.
90% by weight, preferably 30-65% by weight is suitable.

In addition, as an electrically insulating binder (binder resin),
Phenolic resin, urea resin, melamine resin, epoxy resin, silicone resin, vinyl chloride-vinyl acetate copolymer,
Examples include butyral resin, xylene resin, urethane resin, acrylic resin, polycarbonate resin, polyacrylate resin, saturated polyester resin, and phenoxy resin.

Furthermore, the solvent that dissolves these resins varies depending on the type of resin, and it is desirable to select one from among those that do not dissolve the underlayer described below. Specific organic solvents include alcohols such as methanol, ethanol and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and cyclohexane, and N,N-dimethylformamide.

Amides such as N,N-dimethylacetamide, Te1~
Ethers such as hydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, chloroform, methylene chloride,
Aliphatic halogenated hydrocarbons such as dichloroethylene, carbon tetrachloride, trichloroethylene, or benzene,
Aromatic compounds such as toluene, xylene, monodichlorobenzene, and dichlorobenzene can be used.

The thickness of the charge generation layer is approximately 0.1 to 0.51 jIri in order to maintain chargeability and ensure stability. Furthermore, a plasticizer or the like can be used together with the binder if necessary. Coating methods include dip coating, spray coating, and wire bar coating.

This can be carried out using a coating method such as a blade coating method or a roller coating method.

As the binding resin used for the base layer, nylon 6,
Nylon 66, nylon 11. Alcohol-soluble polyamides such as nylon 610° copolymerized nylon and alkoxymethylated nylon, casein, polyvinyl alcohol, 21-cellulose, ethylene-acrylic acid copolymer, gelatin, polyurethane, polyvinyl butyral, and the like are used. The underlayer can be formed by the same method as that for the charge generation layer described above. In this case, the thickness of the base layer is preferably 0.1 to 20 mm, preferably 0.5 to 10 mm.

The electrophotographic photoreceptor of the present invention can be used not only for laser beam printers but also for semiconductor lasers with a wavelength of 750 to 850 nm.
It can also be applied to various other optical storage devices using m light sources.

The present invention will be described in detail below, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

[Examples] Example 1 In this example, a crosslinked polystyrene compound represented by formula (4) was produced by a method represented by the following series of reaction formulas.

(3) (In the formula, x/y represents 9 to 1) (4) (In the formula, X/y represents 9 to 1) Production of compound (1) 1! In a flask, metal magnesium 14. 79, 20% ethyl ether and a small amount of ethyl bromide were added and heated to activate the magnesium.Furthermore, 4-chlorostyrene 81.81j/tetrahydrofuran (THF>
400mf! solution was added over a period of 3 hours. During the reaction, heat was generated and the temperature reached a high temperature, so the reaction solution was kept at 50° C. or lower by cooling in a water bath.

After the dropwise addition was completed, the reaction was continued for another 2 hours at room temperature.

Dimethylformamide (DMF>43.89) was added dropwise over a period of 2 hours and allowed to stand overnight at room temperature.

500 d of ethyl ether was added, and the reaction solution was added to a dilute aqueous hydrochloric acid solution. After extraction, the ether layer was washed with pure water and dried over magnesium sulfate. After distilling off the ether, it was distilled to produce 4-formylstyrene (boiling point 70'
C/0.8 mmHg), yield was 42 g (63%).

Preparation of Compound (2) 66 g of Compound (1) prepared by the above method, 92.59 g of 1.1 diphenylhydrazine. 300 dl of benzene and a small amount of para-toluenesulfonic acid were placed in a 500 d flask equipped with a Dean-Starck receiver and heated to reflux for 2 hours. After the reaction was completed, benzene was distilled off and recrystallized from methanol to obtain Compound (2) as a pale yellow solid with a melting point of 79°C.

15 g of compound (2), 0.67 g of 4-vinylbenzyl alcohol, and 15 g of benzene were placed in an upper left L 50 d flask, and azobisisobutyronitrile (AIBN>
0.5g was added. After polymerization was carried out at 60'C for 24 hours, the polymerization solution was poured into a large amount of methanol. The obtained solid was dried at 50°C under reduced pressure. Yield 13.5'j
, weight average molecular weight 90,000.

Compound (3) having a number average molecular weight of 65.000 was obtained.

Production of Compound (4) After dissolving 13.5 g of Compound (3) in 56 g of methylene chloride, 0.41 g of 1,3-benzenediisocyanate was added and reacted at 50°C for 15 hours to obtain Compound (4). was manufactured.

Example 2 In this example, a crosslinked polystyrene compound represented by formula (6) was produced by a method represented by the following reaction formula.

(In the formula, X/V represents 99-1) (In the formula, x/y represents 99-1) n3 (6) i ooy 15.0 g of compound (5) in the flask
, 15tj of 1.1-diphenylhydrazine, 50ml of tetrahydrofuran, and 0.19ml of toluenesulfonic acid were charged, and the reaction was carried out at room temperature for 4 hours. After the reaction was completed, the solution was poured into 500ml of methanol, the precipitate was filtered,
Drying was performed to produce compound (3). Yield 16.5
It was 9.

Next, after dissolving this compound (3) 16.5'j in methylene chloride 689, 0.50 g of 2,4-toluene diisocyanate was added and reacted at 50°C for 15 hours to produce compound (6). did.

Example 3 Polyamide (East C) l- on aluminum (Δ) substrate
8000) (film thickness: 2 mm) was formed, and on the underlayer, a polyvinyl butyral film (57% by weight) containing oxytitanium phthalocyanine was formed as a charge generation layer.
A solution of compound (3)/2.4-toluene diisocyanate/methylene chloride (weight ratio 20:1:40) was applied onto an aluminum substrate coated with a film thickness of 0.2IJJn), and the mixture was heated at 50°C for 15 hours. A charge transfer layer having a thickness of 151jIr1 was formed by baking. In this way, an electrophotographic photoreceptor having a laminated photosensitive layer was obtained.

This photoreceptor was tested using an electrostatic copying paper tester (Kawaguchi Electric Seisakusho EP).
^-8100), first apply a voltage of -5 kV to the photoreceptor in a dark place.
Charged by corona discharge of
is the charging potential after 5 seconds).

Next, it was exposed to white light with an illuminance of 5 (lx), and the exposure "El/2 (IX-3)" required for the surface to be attenuated by half was determined.

The results are Vo=-1020(V), V5/V□
=-970 (V), El/2 = 0.90 (l
x −s ) and exhibited very good electrophotographic properties and mobility.

The mechanical properties were also very good.

FIG. 1 is a schematic cross-sectional view of the photoreceptor manufactured in Example 3.
In the figure, 1 is a β substrate, 2 is a charge generation layer, 3 is a charge transfer layer, and 4 is an underlayer.

[Effects of the Invention] As explained above, the novel crosslinked polystyrene compound of the present invention has excellent mechanical properties and high mobility when used as a charge transfer material in an electrophotographic photoreceptor. Therefore, it is expected to be useful as a material with excellent functionality.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of an electrophotographic photoreceptor according to the present invention. 1... A1 substrate 2... Charge generation layer 3... Charge transfer layer 4... Base layer agent

Claims (3)

[Claims] (1) General formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, an alkoxyl group, or a dialkylamino group) and the general formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^2 represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms.) A cross-linked polystyrene compound having a hydrazone group in its side chain. (2) General formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, an alkoxyl group, or a dialkylamino group) A styrenic copolymer consisting of structural units represented by the formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and a general formula; 2 represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms. (3) General formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, an alkoxyl group, or a dialkylamino group) and the general formula; ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^2 represents a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms.) An electrophotographic photoreceptor comprising a crosslinked polystyrene compound as a charge transfer material.