JPH01172839A - Charge generating material and production thereof - Google Patents

Abstract

PURPOSE:To obtain a charge generating material which forms carriers with visible light and has excellent film formability by providing a specific rhodanine drive. regularly to the side chain of a chain high polymer. CONSTITUTION:The rhodanine deriv. expressed by the formula I is provided regularly in the side chain of the chain high polymer. In the formula I, R1 denotes a lower alkyl group substd. or unsubstd. aryl group, hydrogen atom, hydroxyl group. The polymer which generates the carriers with the visible light has the rhodanine ring in the molecular chain and a quinoline group intro duced via an ethane diirdene group in the 5-place of the rhodanine ring. This polymer, the rhodanine ring group of which is considered to be an electron acceptor and the quinoline part is an electron donor, forms a color by forming an intra-molecular charge transfer type complex. The uniform thin film which generates the carriers with the visible light, dissolves in a solvent and is subjected to molecular dispersion by mere coating is thereby obtd.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a charge generating material used in an electrophotographic photoreceptor, etc.
(Regarding a charge-generating material that generates carriers with visible light and has excellent film-forming properties, and a method for producing the same.)

(Prior Art) An electrophotographic photoreceptor is a practical device using an organic photoconductive compound. Among these organic photoconductive compounds, polymeric photoconductive substances such as polyvinylcarbazole (PVCz) have high film-forming properties (and are suitable for devices that require a large area such as electrophotographic photoreceptors). However, all of these polymeric substances have large aromatic rings or heterocycles in their main chains or side chains, and they can be excited by absorption of ultraviolet light using a chain of π-electron systems. Photoconductivity is obtained by the movement of carriers generated by the dissociation of excitons.The generation efficiency of carriers is low in the visible light region, so it is used as a charge transport material, or as an organic pigment or dye. It is often used with materials that are sensitive to visible light such as hydrazone derivatives.Although low-molecular photoconductive materials such as hydrazone derivatives have high electrical conductivity, their carrier generation efficiency in the visible light region is similar to that of polymer-based materials. Since it has a low surface resistance and no film-forming properties, it is used as a charge-generating material together with resins and the above-mentioned sensitizers to create photoreceptors.

On the other hand, organic pigments and dyes are substances that have an absorption region in the visible light region and have high carrier generation efficiency.

Since these substances have almost no electrical conductivity or film-forming properties, they are used as charge-generating materials by being dispersed in resins or in the aforementioned charge-transporting materials.

(Problems to be Solved by the Invention) As mentioned above, photoconductive polymers do not show conductivity to visible light, and low-molecular conductive compounds such as hydrazone derivatives do not generate carriers, so they are not suitable for electrophotography. When used as a photoreceptor, it cannot be used alone and requires the addition of dyes or pigments that are sensitive or sensitizing to visible light.

Therefore, since all of these methods require dispersion of the pigment into the binder resin, there are problems with the dispersion method, stability of the dispersion, and the like.

That is, it is difficult to uniformly disperse a pigment insoluble in a solvent in a binder resin, and there are also problems in that the stability of the dispersion liquid is poor, resulting in a shortened lifespan of the coating liquid.

Furthermore, since pigments are aggregates, differences in the conditions of the pigment manufacturing process greatly affect the electrophotographic characteristics of the photoreceptor produced. To solve this problem, there was a technical problem in controlling the physical properties of pigments.

Therefore, an object of the present invention is to provide a charge-generating material that generates carriers using visible light and has excellent film-forming properties, and a method for producing the same.

(Means for Solving the Problems) That is, according to the present invention, there is provided a charge generating material in which rhodanine derivatives are regularly provided in the side chains of a chain polymer. Furthermore, a monomer having a reactive substituent is bonded to a rhodanine derivative having a reactive substituent, and using as a starting material a heptamer, which is obtained, is polymerized in the presence of a radical initiator. A method for producing a charge generating material is provided.

(Function) The polymer that generates carriers with visible light of the present invention has a rhodanine ring in its molecular chain and a quinoline group introduced into the 5-position of the rhodanine ring via an ethanediylidene group. In the above polymer, the rhodanine ring part is considered to be an electron acceptor, and the quinoline part is considered to be an electron donor, forming an intramolecular charge transfer complex to develop color.

In other words, π was delocalized in the ground state electron donor.
When electrons transfer to the empty orbit of the electron acceptor through the group r=C=CH-CH=J, light energy is absorbed and color is generated. Photocarriers are generated by this photoexcitation.

Furthermore, since the charge generating material of the present invention that generates photocarriers is a polymer itself, it has excellent film-forming properties and light transmittance.

In addition, the chain polymer has rhodanine derivatives regularly in its side chains, and since adjacent rhodanine derivatives are close to each other, hole states can be transferred to rhodanine derivatives one after another, and carrier transport ability is also generated. do.

Furthermore, in order to improve the carrier transport ability, the charge generating material of the present invention is preferably combined with a hole transport agent such as a hydrazone derivative, a triphenylamine derivative, or a pyrazoline derivative. It can be made into a polymer-type photoconductive material that can be transferred through a hole transport agent which is made compatible with the polymer.

In this case, since no pigment or the like is dispersed in the photoconductive material itself, the photoconductive material has excellent film-forming properties, light transmittance, and stability.

(Preferred Embodiment of the Invention) The charge generating material as a polymer of the present invention includes a monomer obtained by bonding a rhodanine derivative having reactivity to a monomer having a reactive substituent. Obtained by polymerization using an initiator.

Rhodanine M'', which is a component of such a polymer, has the following formula (% formula %) (in the formula, B is a reactive substituent, (C) is a divalent organic group, R is a lower alkyl group, hydroxyl group, P indicates 0 or l). Examples of (C) include an alkylene group having 4 or less carbon atoms, an arylene group such as a phenylene group, and a carbonyloxyalkylene group such as carbonyloxyethyl and carbonyloxypropyl group. Examples of alkyl groups for R1 include lower alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl groups, and examples of aryl groups that may have substituents include phenyl, naphthyl, Examples include anthryl, phenanthryl, fluorenyl, etc. Substituents include lower alkyl groups having 1 to 4 carbon atoms, alkoxy groups such as methoxy, ethoxy, and propoxy, amino groups, and alkyl groups such as dimethylamino, diethylamino, and dipropylamino groups. Examples include an amino group and a halogen atom.

Specifically, S As shown in the above specific example, the reactive substituent B is -C
00H1-C1l□CI, -011, -COCI, -N
An example is Hz.

These rhodanine derivatives can be synthesized by various methods, such as the following reaction formula.

■- (In the formula, B, (C), P, and R are the same as above) That is, the above rhodanine derivative has 3-substituted rhodanine and 4-β
- It can be obtained by reacting a seventoanilide vinylquinoline alkyl iodide in an alcohol.

Examples of monomers having reactive substituents to which the rhodanine derivatives described above are bonded include the following formula (% formula %) (wherein R2 is -CI□CI, -NH3, -SO□C1,
Styrenic monomer represented by -COOH) (formula % formula %) (in the formula, R3 is a hydrogen atom and a methyl group, R4 is a reactive substituent -C0011, -COCI, -011, -
Ethylene monomer represented by Nlh, n is O or 1, m is an integer of 0 to 3), for example, the following formula (%) R1R3 CHt=CCHz=C COOHCOCI R, R3 CH2=CCH2=C c=o c=.

An example is an acrylic or methacrylic monomer represented by (CHz)lINHzH.

The reaction between the monomer and the rhodanine derivative is achieved, for example, by the following reaction.

(Margin below) H2 p.

As the alkali, pyridine, triethylamine, etc. are used.

The charge generating material of the present invention having rhodanine derivatives regularly in the side chains of a chain polymer can also be obtained by bonding rhodanine derivatives to the side chains of the chain polymer. It is more reliable to obtain it by polymers and copolymers of the same type.

This includes azo compounds such as azobisisobutylnitrile in solvents such as tetrahydrofuran, benzene, dimethylformamide, and dichloromethane, and peroxides such as benzoyl peroxide, cumene hydroperoxide, butyl hydroperoxide, and lauroyl peroxide. It is easily polymerized by heating in the presence of a radical initiator.

The radical initiator concentration is 0 for the molar ratio of the monomers.
．． It is preferably 01 to 0.1 mol%. The polymerization temperature varies depending on the type of radical initiator used, but is usually preferably 20 to 100°C.

Moreover, the polymerization time is preferably 20 to 50 hours. The molecular weight of the resulting polymer can be varied from 1o, ooo to 40, by selecting the monomer concentration, radical initiator concentration, and polymerization temperature.
It can be adjusted widely within the range of 000.

(Effects of the Invention) The polymer according to the present invention generates carriers with visible light, so there is no need for visible light sensitization unlike conventionally known polymeric photoconductive substances such as PvC2, so it is a carrier-generating pigment. It does not need to be used in combination with hydrazone derivatives, triphenylamine derivatives, pyrazoline derivatives, etc., and easily forms a solid solution with conventionally known charge transport materials, if necessary.

Therefore, a uniform thin film with molecularly dispersed molecules can be easily created by simply dissolving it in a solvent and applying it.

Furthermore, since it is a high-molecular compound, there are fewer sanitary fishing records compared to low-molecular compounds.

(Example) Hereinafter, the present invention will be explained in more detail based on Examples.

Example 1 [Synthesis of rhodanine derivative] Synthesis of 3-carboxymethyl-5-(4-(1-ethylquinoline)dimetine) rhodanine 19.1 g of 3-carboxymethyl rhodanine and 4-β-acetanilide vinylquinoline ethiodide After refluxing 46.6 g and 12.1 g of triethylamine in ethanol for 30 minutes, the product was recrystallized from pyridine to obtain the above compound (
yield 53%).

[Synthesis of monomer bound to rhodanine derivative] Synthesis of 3-erboxymethyl-5-(4-(1-ethylquinoline)dimethine) rhodanine polymethylstyrene 15.2
37.2 g of rhodanine and 12 ml of triethylamine are dissolved in 100 ml of dimethylformamide and reacted at 100° C. for 3 hours to synthesize.

After the reaction, the reaction solution was poured into water, the resulting precipitate was washed with water, and then recrystallized with acetone to obtain the above monomer. vinegar,
A charge generating material was obtained in which N-substituted-5-(4-(1-ethylquinoline)dimethine)rhodanine was supported on the side chain of polystyrene.

[Solution polymerization]

Add α to 4.3 g of the monomer obtained above as a polymerization initiator.
, 6 mg of α°-azobisisobutyronitrile and 5 ml of tetrahydrofuran as a solvent were added, and after dissolving the above mixture, the mixture was charged into a polymerization tube, degassing was repeated several times, and an ampoule was prepared in a sufficiently vacuum state by the sealing tube method.

This was immersed in a constant temperature bath at 60° C. for 30 hours to react, yielding 4.1 g of the charge generating material of the present invention.

[Preparation of photosensitive material]

7 parts by weight of a charge generating material carrying the obtained rhodanine derivative on its side chain, 4-diethylaminobenzaldehyde-1
, 3 parts by weight of 2-diphenylhydrazone were dissolved in 100 parts by weight of THF, and the solution was coated on an aluminum sheet using a doctor blade and dried at 100° C. for 30 minutes to prepare a 20 μm electrophotographic photoreceptor.

Example 2 [Synthesis of rhodanine derivative] Synthesis of 3-amino-5-(4-(1-ethylquinoline)dimethine) rhodanine 3-amino rhodanine was used instead of 3-carboxymethyl rhodanine in Example 1. The above compound was obtained in the same manner as in Example 1 (yield: 51%).

[Synthesis of monomer bound to rhodanine derivative] Synthesis of 3-methacrylamide-5-(4-(1-ethylquinoline)dimethine) rhodanine methacrylic acid chloride 10.
5g and 3-amino-5-(4-(1-ethylquinoline)
Dimethine] 34.2 g of rhodanine are reacted in 100 ml of pyridine at 80° C. for 3 hours. After the reaction, the reaction solution was poured into water, the resulting precipitate was washed with water, and then recrystallized with acetone to obtain the above monomer.

[Solution polymerization]

3.5 g of the charge generating material of the present invention was obtained in the same manner as in Example 1 above, except that 3.8 g of the monomer obtained above was used.

Except that the charge generating material was the compound obtained from the above,
A photoreceptor was produced in the same manner as in Example 1 above.

Example 3 [Synthesis of rhodanine derivative] 3-(P-chloromethylphenyl)-5-(4-(
Synthesis of 1-methylquinoline)dimethine]rhodanine Instead of 3-carboxymethylrhodanine in Example 1, 3-(P-chloromethylphenyl)rhodanine was used, and 4-β-acetanilide vinylquinoline ethiodide was used. The above compound was obtained in the same manner as in Example 1 using 4-β-acetanilide vinylquinoline methiodide (yield: 63%).

[Synthesis of monomer bound to rhodanine derivative] 3-(P
Synthesis of rhodanine 8.6 g of methacrylic acid and 3-(P-chloromethylphenyl')-5-(4-(1-methylquinoline)dimethine) ) dimetine]
41.9 g of rhodanine and 12 ml of triethylamine in 1
Dissolve in 00ml of dimethylformamide and react at 100°C for 3 hours.

After the reaction, the reaction solution was poured into water, the resulting precipitate was washed with water, and then recrystallized with acetone to obtain the above monomer.

[Solution polymerization]

4.3 g of the charge generating material of the present invention was obtained in the same manner as in Example 1 above, except that 4.6 g of the monomer obtained above was used.

Except that the charge generating material was the compound obtained from the above,
A photoreceptor was produced in the same manner as in Example 1 above.

11 ri 01 optical power value In order to examine the charging characteristics and photosensitivity characteristics of the above electrophotographic photoreceptor, an electrostatic copying paper tester (manufactured by Kawaguchi Electric Co., Ltd., model 5P-428) was used, and a voltage of +6.0 kV was used. By performing corona discharge for 5 seconds under the following conditions, each photoreceptor is positively charged, and the surface potential at this time is . was measured. Next, using a tungsten lamp, the illumination intensity on the surface of the photoreceptor was adjusted to 201 ux, and exposure was performed using the tungsten lamp.
The time required for the surface potential to reach the above-mentioned surface potential V-'l/2 was determined, and the half-reduction exposure i1EI8 was calculated.

Table 1 shows the measurement results of the charging characteristics and photosensitive characteristics of each photoreceptor.

(The following is a blank space) Table 1 As can be seen from Table 1, the photoreceptor using the charge generating material of the present invention had excellent charging properties, had a small half-decrease exposure amount, and exhibited good electrophotographic characteristics.

Patent applicant: Sanda Kogyo Co., Ltd.

Claims (2)

[Claims] (1) There are rhodanine derivatives with the following structural formula regularly on the side chains of chain polymers ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 is a lower alkyl group, a substituted or unsubstituted aryl group, a hydrogen atom, A charge-generating material having a hydroxyl group). (2) The following general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, B is a reactive substituent, (C) is a divalent organic group, R_1 is a lower alkyl group, substituted or unsubstituted aryl A monomer obtained by reacting a rhodanine derivative represented by a group, a hydrogen atom, a hydroxyl group, P represents 0 or 1) with a monomer having a reactive substituent in the presence of a radical initiator. 1. A method for producing a charge-generating material, which comprises polymerizing the material under the following conditions.