JP3021530B2 - Method for producing high-purity titanyl phthalocyanine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a stable and industrial method for producing high-purity titanyl phthalocyanine, which is suitable as a photoconductive material such as a charge generating layer material of an electrophotographic photoreceptor. It is.

(Prior art and its problems) Phthalocyanine has recently been attracting attention as an excellent photoconductive material, and is referred to as, for example, a charge generation layer (2) as shown in FIG. 1 ((1) is a conductive substrate, (3) The electrophotographic photoreceptor used as the charge transporting layer) has been actively studied because high sensitivity can be obtained up to a long wavelength region. In particular, titanyl phthalocyanine has recently attracted attention as a material having higher sensitivity, and a photoconductor for electrophotography using the same has already been commercialized.

By the way, titanyl phthalocyanine is generally produced by hydrolyzing dichlorotitanyl phthalocyanine obtained by reacting O-phthalonitrile and titanium tetrachloride at a temperature of 100 to 300 ° C. in an inert solution as shown in the following formula. Is the titanyl phthalosyl In using anin as a photosensitive material, a crystallization step and a step of homogenizing a crystal form are required.

Therefore, various methods have been proposed as such means, for example, a salt milling method in which a crude synthetic product is heated in an aromatic solvent to grow crystals, and then crushed in a ball mill together with a hard inorganic salt such as salt. ing. However, these conventional means are cumbersome to operate, and the most important sensitivity characteristics of the electrophotographic photosensitive member vary depending on the processing lot, and the sensitivity characteristics differ even with the same crystal structure. Is still inadequate.

(Object of the Invention) The present invention intends to provide an industrial production method of high-purity titanyl phthalocyanine that can stably and industrially produce a photoreceptor without requiring a crystallization step or a uniform step of crystallizing. Things.

(Means of the Invention for Solving the Problems) According to various experimental studies by the present inventors, fluctuations in the photosensitivity and the like of a photoreceptor caused by titanyl phthalocyanine produced by a conventional method are caused by a phthalocyanine complex. Phthalimide content of 5%
In the following, in particular, if it can be highly purified to 0.5% or less, a highly sensitive photoreceptor can be stably and industrially manufactured using the produced titanyl phthalocyanine without requiring a crystallization step or a uniform crystal step as in the conventional method. It has been found that it can be manufactured.

The present invention is to industrially provide high-purity titanyl phthalocyanine that can satisfy the above requirements,
It is characterized in that titanyl phthalocyanine obtained by reacting O-phthalonitrile with titanium tetrachloride and then hydrolyzing it is heated to 50 ° C. or higher together with quinoline as a solvent.

 Hereinafter, the present invention will be described in detail with reference to Examples.

(Example 1) A container equipped with a stirrer, a reflux amount, a thermometer, and a dropping funnel.
Into a 2 l four-necked flask, 322 gr of O-phthalonitrile and 996 gr of quinoline as a solvent are charged and stirred, and 125.5 gr of titanium tetrachloride is dropped by a dropping funnel over about 10 minutes. After the completion, the reaction is completed by heating at 200 ° C. or more for 1 hour using a mantle heater. After standing to cool, 500 ml of methanol was added thereto, followed by stirring, followed by suction filtration.The residue was sufficiently washed with methanol, and the obtained dichlorotitanyl phthalocyanine was heated to a boiling point of a mixture of 600 ml of concentrated aqueous ammonia and 600 ml of exchanged water. The hydrolysis reaction is carried out for 10 hours under the following conditions. Then, the mixture was subjected to suction filtration at room temperature, washed with ion-exchanged water until the washing liquid became neutral, and then further washed with methanol, and then dried with hot air at 90 ° C. for 10 hours to obtain 281.7 gr of a blue-purple titanyl phthalocyanine. .

25 gr of titanyl phthalocyanine produced by this conventional method and 250 gr of quinoline as a solvent are charged into a four-necked flask equipped with a stirrer, a reflux tube and a thermometer, and heated and stirred at 200 ° C. for 2 hours by a mantle heater. After allowing to cool, suction filtration was performed, and the residue was sufficiently washed with methanol, and then dried with hot air at 90 ° C. for 10 hours to obtain 21.8 gr of highly purified titanyl phthalocyanine.

Example 2 The purity of the titanyl phthalocyanine and quinoline in Example 1 was increased by heating and stirring at 150 ° C.

(Example 3) Production was performed by setting the heating and stirring temperature of titanyl phthalocyanine and quinoline in Example 1 to 100 ° C.

(Example 4) Production was carried out by setting the heating and stirring temperature of titanyl phthalocyanine and quinoline in Example 1 to 50 ° C.

For the high-purity titanyl phthalocyanine produced by applying the high-purity means of the present invention according to Examples 1 to 4 and the conventional method described in Example 1, that is, titanyl phthalocyanine before high-purification according to the present invention, phthalimide was used. Table 1 shows the results of the quantification. As a quantitative method, 400 g of chloroform was added to 4 g of the high-purity titanyl phthalocyanine and 4 g of the titanyl phthalocyanine before the high purity in Examples 1 to 4, and the mixture was ground by a ball mill for 20 hours. The method of quantification was used.

Further, a photoreceptor is formed by each of the highly purified titanyl phthalocyanine described in Examples 1 to 4 and the titanyl phthalocyanine before the high purity according to the present invention, and the half-exposure energy (E / 2erg / cm ² ), the results shown in Table 1 and FIG. 2 were obtained.

The manufacturing conditions of the photoreceptor are as follows. The highly purified titanyl phthalocyanine of Examples 1 to 4 and the pre-high purity titanyl phthalocyanine according to the present invention so that the film thickness becomes 500 ° C. at a pressure of 10 ⁻⁵ torr and a heating temperature of 500 ° C. on an aluminum drum as a conductive substrate. Is deposited to form the charge generation layer of FIG. After that, a charge transfer layer (2) consisting of 1 part by weight of polycarbonate and 1 part by weight of 2-methyl-4-dibenzylaminobenzo-1-diphenylhydrazone was applied on the surface so as to have a thickness of 20 μm. To
After drying at 80 ° C. for 1 hour, a photoconductor for electrophotography was formed. The half-exposure energy was measured by setting the voltage so that the corona discharge current was 17 μA in a dark place. After negatively charging the photoreceptor by corona discharge with an applied voltage, the photosensitive member was exposed to white light, and the surface potential was − Exposure energy was halved from 750 volts to -375 volts.

As is clear from Table 1, the highly purified titanyl phthalocyanine according to the present invention shown in Example 1 has a significantly lower phthalimide content than the conventional one, and can be controlled by the treatment temperature. As is clear from Table 1 and FIG. 2, the half-life exposure energy is significantly smaller than that of the conventional one, indicating that a photosensitive member having high sensitivity can be obtained.

In each of the above embodiments, quinoline was used as a solvent. As a comparative example, phthalimide was used for those treated with pyridine, dimethylformamide, methanol, dioxane, ethanol, tetrahydrofuran, toluene, ethyl acetate, chloroform and acetone. Was obtained, the result of FIG. 3 was obtained. As is clear from this, it is found that the quinoline of the present invention using the quinoline as the solvent is excellent.

The purification operation with each solvent was performed as follows. In a 100 ml four-necked flask equipped with a stirrer, a reflux tube, and a thermometer, 6 gr of titanyl phthalocyanine before purification according to the present invention and 60 gr of a solvent are charged, and the mixture is heated and stirred at a boiling point for 2 hours by a mantle heater. After standing to cool and suction filtration, the residue is sufficiently washed with methanol, and then 90 ° C.
For 10 hours.

Further, using the highly purified titanyl phthalocyanine according to Example 1 of the present invention and the titanyl phthalocyanine according to the conventional method, 100 photoconductors were manufactured under the above-described manufacturing conditions, and the half-exposure energy was determined. The results as shown in FIG. 4 were obtained.

As is apparent from the above, according to the present invention, a photosensitive member having high sensitivity can be manufactured with little variation among manufacturing lots, and is effective in industrial manufacturing.

(Effects of the Invention) As described above, according to the present invention, a high-sensitivity electrophotographic photoreceptor can be manufactured with a small variation in performance without requiring a crystallization step or a crystal homogenization step. It can provide a method for industrially stably producing titanyl phthalocyanine, and has a great effect when used in the production of electrophotographic photoreceptors.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a function-separated type electrophotographic photoconductor, and FIG.
FIGS. 3, 3 and 4 are an exposure sensitivity curve of the photoreceptor using the titanyl phthalocyanine of the present invention, a comparison diagram of the solvent effect, and a half-exposure energy distribution diagram according to the production lot.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Mochizuki 1014 Miyaharacho, Kofu City, Yamanashi Prefecture Inside Yamanashi Electronics Industry Co., Ltd.

Claims (1)

(57) [Claims] 1. A high-purity titanyl phthalocyanine characterized in that titanyl phthalocyanine produced by reacting O-phthalonitrile with titanium tetrachloride and then hydrolyzing is heated together with a solvent quinoline to 50 ° C. or higher. Production method.