JPH0723453B2 - Disazo compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a disazo compound.

2. Description of the Related Art Heretofore, it has been known that a certain kind of disazo compound is effective as a charge generating pigment used in a charge generating layer of a laminated type photoreceptor which is one form of an electrophotographic photoreceptor. The term "multilayer type photoreceptor" as used herein means a charge-generating pigment having the ability to generate charge carriers by light on a conductive support by a suitable method, such as vacuum deposition, coating with a pigment solution or pigmenting a resin solution. The charge generation layer is formed as a thin layer by applying a dispersion liquid in which the fine particles are dispersed, and the charge carriers generated in the charge generation layer can be efficiently injected onto the charge generation layer, and the charge transfer is performed where it moves. It is a photoreceptor on which a layer (generally, this charge carrier layer is composed of a charge carrier substance and a binder resin) is formed. Conventionally, as a disazo compound used for this type of photoreceptor, for example, Japanese Patent Application Laid-Open No.
-37543 and JP-A-52-55643, or benzidine-based disazo compounds or JP-A-52
There are known stilbenzene-based disazo compounds and the like described in JP-A-8883. However, there is a deficiency in that the laminated type photoreceptor using the conventional disazo compound generally has low sensitivity.

OBJECT The object of the present invention is to provide a novel disazo compound which is effective in an electrophotographic photosensitive member, and particularly effective in the above-mentioned laminated type photosensitive member. The photoconductor has higher sensitivity than a photoconductor using a conventional disazo compound.

Structure That is, the present invention is a disazo compound represented by the following general formula (I).

[In the formula, A is (Wherein R ₁ represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group or a halomethyl group,
n is an integer of 0, 1, 2 or 3, and when n is an integer of 2 or 3, R ₁ may be the same or different groups)] The disazo compound of the present invention is , Formula (II) The diamino compound represented by (Wherein, X represents an anion functional group), and the tetrazonium salt and the general formula (IV), (V) or (VI) (In the formula, R ₁ represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group or a halomethyl group, and n is 0, 1,
In the case where n is an integer of 2 or 3, R ₁ may be the same or different groups, and R ₂ is a substituted or unsubstituted alkyl group, a substituted or unsubstituted group. Which represents an aryl group of) and a compound represented by

Anions in the tetrazonium salt compound of the general formula (III)
Cl is a typical example of an on-functional group. , Br , I , BF_Four , PF₆
，ClO_Four ，AsF₆ , SbF₆ And preferably BF_Four Is.

The disazo compound represented by the general formula (I) of the present invention is useful as a charge generating substance for a laminated electrophotographic photoreceptor as described above, and further, a charge generating substance and a charge carrier substance are dispersed in a resin. It is also useful as a charge generating substance in an electrophotographic photoreceptor having a single-layer type photosensitive layer, and as a photoconductive substance in an electrophotographic photoreceptor having a photosensitive layer in which a photoconductive substance is dispersed in a resin. is there.

The tetrazonium salt represented by the general formula (III) of the present invention can be obtained by commercially available 3,3 ′, 5,5′-tetramethylbenzidine (for example, commercially available from Wako Pure Chemical Industries, Ltd.) Can be obtained by diazotization.

The diazotization of 3,3 ′, 5,5′-tetramethylbenzidine is
This is done by adding sodium nitrite at -10 ° C to 20 ° C in an inorganic acid such as hydrochloric acid or sulfuric acid. The diazotization reaction is completed in about 30 minutes to 3 hours. Further, a tetrazonium salt can be obtained by adding, for example, borofluoric acid or an aqueous sodium borohydride solution to the diazotization reaction solution.

The production of the disazo compound represented by the general formula (I) can be carried out by allowing the diazotization reaction solution as it is to act on a cupler, or the diazotization reaction solution can be treated with, for example, borohydrofluoric acid. Alternatively, it can also be obtained by isolating the tetrazonium salt by adding an aqueous solution of sodium borofluoride or the like to precipitate the tetrazonium salt of the general formula (III), and then reacting the tetrazonium salt with the cupler. Actually, this reaction is carried out by dissolving the tetrazonium salt and the cuppler in an organic solvent such as N, N-dimethylformamide (DMF) or dimethylsulfoxide (DMSO) at about -10 ° C to 40 ° C. It is carried out by dropping an alkaline aqueous solution such as an aqueous sodium acetate solution. The reaction is completed in about 5 minutes to 3 hours. After completion of the reaction, the precipitated crystals are collected by filtration and purified by an appropriate method (eg, washing with water and / or organic solvent, recrystallization method, etc.)
By doing so, the production of the disazo compound is completed.

The disazo compound of the present invention is a colored crystal at room temperature, and specific examples thereof are shown in Table 1 below together with melting points, elemental analysis values and infrared absorption spectrum data.

Example 1 (Production of Disazo Compound No. 1) Production of tetrazonium salt To 140 ml of 20% hydrochloric acid 3,3 ′, 5,5′-tetramethylbenzidi
9.61g, and after stirring well, cool to 2 ° C and then
Then dissolve 5.97 g of sodium nitrite in 10 ml of water.
The resulting solution was added dropwise at a temperature of 2 ° C to 7 ° C over 10 minutes.
Then, after stirring for 20 minutes at the same temperature, the reaction solution was added to about 2.5
42% hydrofluoric acid in the resulting red solution
100 ml was added, and the precipitated crystals were filtered off, washed with water and dried to 1
6.5 g (yield 94.2%) of tetrazonium bistetrafluor
A robrate crystal was obtained. Infrared absorption spectrum (KBr
Tablet method) is 2280 cm^-1To N₂ Absorption based on

Production of Disazo Compound No. 1 N, N-dimethylformamide obtained by cooling 1.09 g of the tetrazonium salt obtained above and 1.45 g of 2-hydroxy-3-naphthoic acid benzylidene hydrazide (twice the mole of the tetrazonium salt) as a coupling component. Dissolve in 150 ml and add a solution of sodium acetate 0.82 g and water 7 ml to
The mixture was added dropwise at a temperature of 10 ° C. over 20 minutes, cooling was stopped, and the mixture was further stirred at room temperature for 3 hours. Then, the precipitate formed was filtered off and heated to 80 ° C. with N, N-dimethylformamide.
Wash 3 times with 200 ml, then 2 times with 200 ml water, at 80 ° C
It was dried under reduced pressure of 2 mmHg to obtain 8.2 g (yield 65.9%) of the disazo compound of Compound No. 1 in Table-1. The appearance of this disazo compound is a purple black powder, and the infrared absorption spectrum (KBr tablet method) is shown in FIG.

Examples 2 to 6 (Production of Disazo Compound Nos. 2 to 6) The same as Example 1 except that the compounds of Table 2 below were used as the coupling component in the production of the disazo compound of Compound No. 1 of Example 2. Compound No. 2 shown in Table 1 by the method
~ 6 disazo compounds were prepared.

The infrared absorption spectra of the disazo compound of the present invention are shown in FIGS.

Fig. 1-Compound No. 1 Fig. 2-Compound No. 2 Fig. 3-Compound No. 3 Fig. 4-Compound No. 4 Fig. 5-Compound No. 5 Fig. 6- Compound No.6 Effect As described above, the disazo compound of the present invention is effective as a photosensitive material of an electrophotographic photosensitive member, particularly as a charge generating material of a laminated type photosensitive member. Here is an example: Further, in order to clarify the inventive step of the present invention, a comparison with a conventional disazo compound is also shown.

Application Example 76 parts by weight of the disazo compound No. 5 of the present invention, 1260 parts by weight of a tetrahydrofuran solution (solid concentration 2%) of a polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.), and 3700 parts by weight of tetrahydrofuran are ground in a ball mill. The obtained dispersion liquid was mixed and applied on the aluminum surface of an aluminum-deposited polyester base (conductive support) using a doctor blade, and naturally dried to form a charge generation layer having a thickness of about 1 μm. On the other hand, 9-ethylcarbazole-3-
2 parts by weight of aldehyde 1-methyl-1-phenylhydrazone, 2 parts by weight of polycarbonate resin (Panlite K1300, Teijin Kasei Co., Ltd.) and 16 parts by weight of tetrahydrofuran were mixed and dissolved to form a solution. The layer is coated with a doctor blade and dried at 80 ° C. for 2 minutes and then at 100 ° C. for 5 minutes to form a charge transport layer having a thickness of about 20 μm, and the laminated photoreceptor (A) shown in FIG. 7 is formed. Created.

For comparison, according to the procedure for preparing the above-mentioned photoreceptor, the above-mentioned JP-A-45-37543 and JP-A-52-556 were used instead of the disazo compound of the present invention.
4,4'-bis (2-hydroxy-3-phenylcarbamoyl-1-naphthylazo) -3,3'-dichlorodiphenyl which is a benzidine-based disazo compound disclosed in JP-A-43- The stilbene disazo compound 4,4'-bis (2-hydroxy-3-
A photoconductor (B) and a photoconductor (C) were prepared in the same manner except that phenylcarbamoyl-1-naphthylazo) stilbene was used.

The electrostatic characteristics of the photoconductors (A), (B) and (C) thus produced were measured using a commercially available electrostatic copying paper tester (Kawaguchi Denki Seisakusho, SP-428 type). did. That is, first, apply a -6KV corona discharge to the photoreceptor 20 times.
The voltage was negatively charged for 2 seconds, the surface potential at that time was measured to obtain Vdo (volt), and dark decay was performed for 20 seconds in a dark place, and the surface potential at that time was measured to be Vpo (volt). Then, the photosensitive layer is irradiated with light from a tungsten lamp so that the surface has an illuminance of 20 lux, and the time (seconds) until the surface potential becomes 1/2 Vpo is obtained, and the exposure amount E1 / 2 ( Lux seconds. Similarly, find the time (seconds) until it becomes 1/5 and 1/10 of Vpo, and the exposure amount E1 / 5
(Ruxus second) and E1 / 10 (Ruxus second) were calculated. The results are shown in Table-3.

As is clear from the results in Table 3, the photoconductor (A) using the disazo compound of the present invention has higher sensitivity than the photoconductors (B) and (C) using the conventional disazo compound. I understand.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to FIG. 6 are infrared absorption spectrum diagrams (KBr tablet method) of representative disazo compounds of the present invention. FIG. 7 is an enlarged cross-sectional view of the electrophotographic photosensitive member according to the present invention. 11 is a polyester base, 22 is an aluminum vapor deposition film, 33 is a charge generation layer, and 44 is a charge transport layer.

Claims (1)

[Claims] 1. A general formula (I) [Where A is (Wherein R ₁ represents an alkyl group, an alkoxy group, a nitro group, a halogen, a cyano group or a halomethyl group, and n
Is an integer of 0, 1, 2 or 3, and when n is an integer of 2 or 3, R ₁ may be the same or different groups)].