JP5052216B2 - Titanyl phthalocyanine crystal and method for producing the same - Google Patents

Description

  The present invention relates to a titanyl phthalocyanine crystal and a method for producing the same, and more particularly to a titanyl phthalocyanine crystal for an electrophotographic photoreceptor and a method for producing the same.

  Conventionally, in a digital copying machine and a digital printer, a titanyl phthalocyanine crystal having a high sensitivity characteristic with respect to a long wavelength light of 600 to 800 nm emitted from a light source is known as a material of an electrophotographic photosensitive member (for example, , See Patent Document 1).

  Electrophotographic photoreceptors using titanyl phthalocyanine crystals have high sensitivity to long-wavelength light from the light source, low residual potential, high chargeability, high acceptance potential, potential retention, and high potential stability. Need to be excellent. In addition, if the decrease in chargeability due to repeated use is large, the service life of the electrophotographic photosensitive member is shortened, so the decrease in chargeability due to repeated use must be small.

  The electrostatic characteristics of the electrophotographic photoreceptor using the titanyl phthalocyanine crystal are not only different depending on the crystal form of the titanyl phthalocyanine crystal, but also differ depending on the method for producing the titanyl phthalocyanine crystal.

  In the method for producing a titanyl phthalocyanine crystal described in Patent Document 1, as the first step, 1,2-dicyanobenzene and titanium tetrachloride are combined in the presence of an inert high-melting-point organic solvent (α-chloronaphthalene). Heat reaction. As a 2nd process, the amorphous titanyl phthalocyanine is obtained by carrying out the hot water process of the crude titanyl phthalocyanine obtained by making it heat-react in a 1st process. As the third step, the target titanyl phthalocyanine crystal can be obtained by heat-treating the amorphous titanyl phthalocyanine obtained in the second step with an organic solvent (for example, N-methylpyrrolidone).

  In this manufacturing method, since titanium tetrachloride is used, the produced titanyl phthalocyanine crystal contains chlorine as an impurity, and structural defect sites are introduced. Therefore, the electrophotographic photoreceptor is charged with repeated use. The decline is relatively large. Incidentally, it is difficult to remove chlorine taken into the titanyl phthalocyanine crystal.

  Thus, a method for producing a titanyl phthalocyanine crystal that does not use a metal halide such as titanium tetrachloride has also been proposed (see, for example, Patent Documents 2 to 4).

  In the method for producing a titanyl phthalocyanine crystal described in Patent Document 2, as a first step, 1,3-diiminoisoindoline and titanium tetrabutoxide are used in the presence of an aliphatic solvent (for example, α-chloronaphthalene). Heat reaction. As a second step, amorphous titanyl phthalocyanine is obtained by subjecting the dried crude titanyl phthalocyanine obtained by the heat reaction in the first step to a so-called acid paste treatment. As a third step, the target titanyl phthalocyanine crystal can be obtained by treating the dried amorphous titanyl phthalocyanine obtained in the second step with an organic solvent (for example, o-dichlorobenzene).

  In the method for producing a titanyl phthalocyanine crystal described in Patent Document 3, as the first step, phthalonitrile, titanium tetraalkoxide (for example, titanium tetrabutoxide), urea, and the presence of an organic solvent (for example, n-octanol) are used. The target titanyl phthalocyanine crystal can be obtained by heating under reaction.

In the method for producing a titanyl phthalocyanine crystal described in Patent Document 4, 1,3-diiminoisoindoline and titanium tetrabutoxide are heated and reacted in the presence of sulfolane. As a second step, amorphous titanyl phthalocyanine is obtained by subjecting the dried crude titanyl phthalocyanine obtained by the heat reaction in the first step to a so-called acid paste treatment. As the third step, the target titanyl phthalocyanine crystal can be obtained by treating the amorphous titanyl phthalocyanine obtained in the second step with an organic solvent (for example, tetrahydrofuran) in the presence of water.
Japanese Patent Publication No. 5-31137 Japanese Patent No. 2821765 JP-A-6-293769 JP 2001-19871 A

  However, the electrophotographic photosensitive member using the above conventional titanyl phthalocyanine crystal is not sufficiently stable in chargeability during repeated use, and is still excellent in chargeability stability during repeated use. Thus, a titanyl phthalocyanine crystal having excellent crystal stability has been desired.

  This invention is made | formed in view of the above, Comprising: It aims at providing the titanyl phthalocyanine crystal | crystallization excellent in crystal stability, and its manufacturing method.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

According to one aspect of the present invention, the diffraction peak (± 0.2 °) of the Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542Å) has a maximum diffraction peak at least 26.2 °, 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, 28.3 ° A method for producing a titanyl phthalocyanine crystal having a diffraction peak,
An amorphous titanyl phthalocyanine having a maximum diffraction peak at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542１．５) of CuKα is In the presence, obtained by crystal conversion with an organic solvent containing at least one organic solvent selected from tetrahydrofuran, cyclohexane, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane. Was
As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, it has a maximum diffraction peak at least 27.2 °, and further 9.4 ° and 9.6 °. , Having a main diffraction peak at 24.0 ° and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, between the 7.3 ° peak and the 9.4 ° peak A titanyl phthalocyanine crystal that does not have a peak and does not have a diffraction peak at 26.3 ° is used , and is further subjected to a second crystal conversion.

  According to the present invention, the diffraction peak (± 0.2 °) of Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα has a maximum diffraction peak at least 27.2 °, and further 9.4. The main diffraction peak is at °, 9.6 °, and 24.0 °, and the diffraction peak at 7.3 ° is the lowest diffraction peak, and the peak at 7.3 ° is 9.4 ° By transforming a titanyl phthalocyanine crystal that does not have a peak between 2 ° and has no diffraction peak at 26.3 °, the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα As a diffraction peak (± 0.2 °) having a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 ° , 16.1 °, 20.7 °, 23.2 °, 27.1 °, 28.3 ° Having click, excellent crystalline stability, it is possible to provide titanyl phthalocyanine crystal, and a manufacturing method thereof.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  The method for producing a titanyl phthalocyanine crystal according to this example includes a first step of synthesizing crude titanyl phthalocyanine without using a titanium halide, and a so-called acid paste treatment of the crude titanyl phthalocyanine obtained in the first step. A second step of generating phthalocyanine, and a third step of generating a titanyl phthalocyanine crystal as a precursor by crystal-converting the amorphous titanyl phthalocyanine obtained in the second step with a second organic solvent in the presence of water. And a fourth step of producing a target titanyl phthalocyanine crystal by crystal conversion of the dried precursor obtained in the third step.

  The precursor obtained in the third step has a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-rays (wavelength 1.542 mm). Furthermore, it has major diffraction peaks at 9.4 °, 9.6 °, and 24.0 °, and has a diffraction peak at 7.3 ° as the lowest diffraction peak, and 7.3 °. It is a titanyl phthalocyanine crystal having no peak between the peak of 9.4 ° and the peak of 9.4 ° and further having no diffraction peak at 26.3 °.

  The titanyl phthalocyanine crystal obtained in the fourth step is obtained by crystal conversion of the precursor obtained in the third step, and has a Bragg angle 2θ diffraction peak with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα ( ± 0.2 °) having a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 It is a titanyl phthalocyanine crystal having diffraction peaks at °, 20.7 °, 23.2 °, 27.1 °, and 28.3 °.

  In addition, although the manufacturing method of the titanyl phthalocyanine crystal | crystallization of a present Example consists of a 1st-4th process, as long as it passed through the 4th process, there is no restriction | limiting in the process, For example, the crude titanyl phthalocyanine obtained at a 1st process The amorphous titanyl phthalocyanine obtained in the second step and the precursor having the specific X-ray diffraction spectrum obtained in the third step may be obtained by another production method.

  Hereinafter, each step will be described in detail.

  In the first step, crude titanyl phthalocyanine is synthesized without using a titanium halide. As a method for synthesizing this crude titanyl phthalocyanine, for example, a known method described in Patent Document 3 or Patent Document 4 can be employed. That is, a crude titanyl phthalocyanine crystal can be obtained by heat-reacting a phthalonitrile and a metal alkoxide (for example, titanium tetraalkoxide) in the presence of urea and an organic solvent (for example, n-octanol). Alternatively, a crude titanyl phthalocyanine crystal can be obtained by heat-reacting 1,3-diiminoisoindoline and titanium tetrabutoxide in the presence of sulfolane.

  In this way, by synthesizing crude titanyl phthalocyanine without using titanium halide, it is possible to obtain a titanyl phthalocyanine crystal, which will be described later, with a low halogen element content, and to obtain an electrophotographic photoreceptor excellent in electrostatic characteristics. be able to.

  In the second step, the crude titanyl phthalocyanine obtained in the first step is treated with a so-called acid paste to produce amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine). Specifically, first, the crude titanyl phthalocyanine obtained in the first step is dissolved in 10 to 50 times (mass ratio) of concentrated sulfuric acid, and insoluble matters are removed by filtration or the like as necessary. Next, the crude titanyl phthalocyanine dissolved in concentrated sulfuric acid is slowly added to 10-50 times (mass ratio) of sufficiently cooled water or ice water with respect to concentrated sulfuric acid to precipitate amorphous titanyl phthalocyanine. Next, after filtering the precipitated amorphous titanyl phthalocyanine, washing with ion exchange water and filtration are repeated until the filtrate becomes neutral, and finally a water paste having a solid content concentration of about 5 to 15% by mass is obtained. .

  In the second step, it is important that the precipitated amorphous titanyl phthalocyanine is sufficiently washed with ion-exchanged water so as not to leave sulfate ions as much as possible. Specifically, it is preferable that the ion-exchanged water after washing exhibits physical property values described later.

  When the physical property value of ion-exchanged water after washing is expressed by pH, the pH of ion-exchanged water is preferably in the range of 6-8. This pH value can be measured with a commercially available pH meter.

  Further, when the physical property value of the ion-exchanged water after washing is expressed by specific conductivity, the specific conductivity of the ion-exchanged water is preferably 8 μS / cm or less, more preferably 5 μS / cm or less, and particularly preferably 3 μS / cm or less. . This specific conductivity can be measured with a commercially available electric conductivity meter.

  When the physical property value of ion-exchanged water after washing is within the above range, since the residual amount of sulfate ion in the water paste is small, a titanyl phthalocyanine crystal with low sulfate ion content can be obtained, and the electrostatic characteristics are improved. An excellent electrophotographic photoreceptor can be obtained. When the physical property value of the ion-exchanged water after washing deviates from the above range, in the electrophotographic photoreceptor described later, chargeability and photosensitivity are reduced.

  The amorphous titanyl phthalocyanine obtained in the second step has a maximum of at least 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. It is preferable to have a diffraction peak. More preferably, the half width of the maximum diffraction peak is 1 ° or more. Moreover, it is preferable that the average particle diameter of a primary particle is 0.1 micrometer or less.

  In the third step, the amorphous titanyl phthalocyanine obtained in the second step is crystal-converted with a second organic solvent in the presence of water to produce a precursor. Specifically, the precursor is generated by subjecting the aqueous paste of amorphous titanyl phthalocyanine to crystal conversion using the second organic solvent without drying.

  The type of the second organic solvent is not limited as long as the desired precursor can be obtained, and in particular, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane can be used. preferable. These organic solvents may be used alone, two or more of these organic solvents may be mixed and used, or may be used by mixing with other solvents.

  The ratio (mass ratio) of the second organic solvent to the amorphous titanyl phthalocyanine is preferably 10 times or more, particularly preferably 30 times or more. By using a large amount of the organic solvent in this manner, crystal conversion can be performed in a short time, and impurities contained in the amorphous titanyl phthalocyanine can be removed. Therefore, a titanyl phthalocyanine crystal with little crystal transition and excellent crystal stability can be obtained, and an electrophotographic photoreceptor excellent in electrostatic characteristics can be obtained.

  In a 4th process, the target titanyl phthalocyanine crystal | crystallization is produced | generated by crystal-converting the dried precursor obtained at the 3rd process.

  Crystal transformation of this precursor is performed by applying thermal energy such as crystal transformation by applying a mechanical energy such as a mechanical shearing force, crystal transformation by a first organic solvent, or heat treatment, for example. This is realized by crystal conversion by applying chemical energy such as crystal conversion by evaporation or precipitation after evaporation. Among these means, it is preferable to include at least one of crystal conversion using a first organic solvent and crystal conversion by applying a mechanical shearing force, and further including both. preferable. The means for crystal conversion of the precursor is not limited as long as the precursor can be crystal-converted to the target titanyl phthalocyanine crystal.

  Crystal transformation by the first organic solvent is realized, for example, by immersing the precursor in the first organic solvent and leaving it for a period of one day or longer. A mechanical shearing force may be applied to the precursor while the precursor is immersed in the first organic solvent. By using a mechanical shear force in combination, the crystal transformation of the precursor can be accelerated.

  As the first organic solvent, for example, one kind selected from an ether solvent and a ketone solvent can be used. As the ether solvent, a branched or straight chain ether having 1 to 5 carbon atoms and a cyclic ether are effectively used, and tetrahydrofuran is particularly preferably used among them. As the ketone solvent, a branched or linear ketone having 1 to 5 carbon atoms is used, and 2-butanone is particularly preferably used. The type of the first organic solvent is not limited as long as the precursor can be crystal-converted into the target titanyl phthalocyanine crystal.

  In the fourth step, it is important that the first organic solvent does not contain water as much as possible. Since the precursor is in a stable state in the presence of water, if a large amount of water is contained in the first organic solvent, crystal conversion of the precursor is slow, which is not preferable. The precursor obtained in the third step is preferably dried before the fourth step.

  Crystal transformation by applying mechanical shearing force is realized by applying shearing force to the precursor using, for example, a mixer, a dry ball mill, or a mortar.

  Crystal transformation by heat treatment is realized by, for example, heat-treating the precursor at a high temperature of 100 ° C. or higher. Specifically, the precursor can be crystal-converted into a target titanyl phthalocyanine crystal by heat-treating the precursor in an electric furnace for several hours at a high temperature of 200 ° C. to 400 ° C. When the heating temperature is 400 ° C. or higher, decomposition of the molecular structure of the titanyl phthalocyanine crystal starts, which is not preferable. Further, the heat treatment is preferably performed in a light-shielded state at a high temperature in order to prevent decomposition of the molecular structure of the titanyl phthalocyanine crystal due to light stimulation. In addition, although heat processing may be performed under atmospheric pressure, you may carry out under reduced pressure (for example, 10 mmHg or less).

  Crystal transformation by evaporating and precipitating can be achieved by, for example, heating the precursor by physical vapor deposition (PVD), chemical vapor deposition (CVD), etc. This is realized by attaching a titanyl phthalocyanine crystal.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited to the following Example, A various deformation | transformation and substitution are added to the following Example, without deviating from the scope of the present invention. be able to.

Example 1
According to Patent Document 4, a precursor was synthesized, and the precursor was crystal-converted to produce a target titanyl phthalocyanine crystal.

[First step]
29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After the reaction is complete, the mixture is allowed to cool, and then the precipitate is filtered, washed with chloroform until the powder turns blue, then washed several times with methanol, then washed several times with hot water at 80 ° C. and dried. Crude titanyl phthalocyanine was obtained. In Example 1, no halogen-containing compound was used.

[Second step]
The crude titanyl phthalocyanine obtained in the first step was dissolved in 20 times (mass ratio) concentrated sulfuric acid. Next, this was dripped, stirring to 100 times amount (mass ratio) ice water, and amorphous titanyl phthalocyanine was deposited. Next, the precipitated amorphous titanyl phthalocyanine is filtered, and then repeatedly washed with ion-exchanged water (pH: 7.0, specific conductivity: 1.0 μS / cm) until the washing solution becomes neutral (after washing) The pH value of ion-exchanged water was 6.8, and the specific conductivity was 2.6 μS / cm), and a wet cake (water paste) was obtained. The solid content concentration of the wet cake was 15% by mass.

  1 is a diagram showing an example of an X-ray diffraction spectrum of amorphous titanyl phthalocyanine obtained in Example 1. FIG. The amorphous titanyl phthalocyanine used for the measurement of the X-ray diffraction spectrum was obtained by drying the water paste at 80 ° C. under reduced pressure (5 mmHg) for 2 days. The X-ray diffraction spectrum was measured using an X-ray diffraction apparatus (Rigaku Corporation: RINT1100) under the following conditions. In addition, since the measurement of the following X-ray diffraction spectrum was performed using the same apparatus on the same conditions, description of conditions is abbreviate | omitted in the measurement of the following X-ray diffraction spectra.

X-ray diffraction spectrum measurement conditions X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds In Example 1, as is clear from FIG. 1, the diffraction peak (± 0.2) with respect to the characteristic X-ray (wavelength 1.542１．５) of CuKα, which is the target amorphous titanyl phthalocyanine. The maximum diffraction peak at 7.0 to 7.5 ° and the half-width of the maximum diffraction peak at 1 ° or more could be obtained.

[Third step]
40 g of the wet cake (water paste) obtained in the second step was added to 200 g of tetrahydrofuran as the second organic solvent, stirred for 4 hours, filtered and dried to obtain a precursor. Here, the ratio (mass ratio) of the second organic solvent to the amorphous titanyl phthalocyanine was 33 times.

  2 is a diagram showing an example of an X-ray diffraction spectrum of the precursor obtained in Example 1. FIG. As apparent from FIG. 2, in Example 1, 27.2 as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542１．５) of CuKα, which is the target precursor. Has a maximum diffraction peak at °, further has main diffraction peaks at 9.4 °, 9.6 °, and 24.0 °, and has a diffraction peak at 7.3 ° as the lowest diffraction peak. Thus, a titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° and further having no diffraction peak at 26.3 ° could be obtained.

[Fourth step]
The precursor obtained in the third step was crystal-converted with a first organic solvent described later to obtain the target titanyl phthalocyanine crystal.

  That is, 40 g of the precursor synthesized in the third step and 400 g of 2-butanone as the first organic solvent are put into a ball mill pot with an inner diameter of 150 mm together with 3.5 kg of zirconia balls with a diameter of 2 mm and milled for 24 hours. went. After the treatment with the first organic solvent, the filtered product was vacuum-dried at 100 ° for 1 day to obtain the target titanyl phthalocyanine crystal.

  3 is a diagram showing an example of an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained by crystal conversion of the precursor of Example 1. FIG. As is clear from FIG. 3, in Example 1, as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, which is the target titanyl phthalocyanine crystal, 26. It has a maximum diffraction peak at 2 ° and is further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °. And titanyl phthalocyanine crystals having diffraction peaks at 27.1 ° and 28.3 ° were obtained (this is referred to as crystal 1).

  The evaluation of the titanyl phthalocyanine crystal will be described later together with the evaluation of the titanyl phthalocyanine crystal of the comparative example.

(Examples 2 to 7)
In Examples 2 to 7, titanyl phthalocyanine crystals were obtained in the same manner as in Example 1 except that in the third step, the organic solvent described in Table 1 was used as the second organic solvent instead of tetrahydrofuran. Synthesized.

表１に記載の第２の有機溶媒を用いることで得られた前駆体のＸ線回折スペクトルは、それぞれ、実施例１の前駆体のＸ線回折スペクトル（図２参照）と同様のものであった。つまり、実施例２〜７では、目的の前駆体である、ＣｕＫαの特性Ｘ線（波長１．５４２Å）に対するブラッグ角２θの回折ピーク（±０．２°）として、２７．２°に最大回折ピークを有し、更に９．４°、９．６°、２４．０°に主要な回折ピークを有し、かつ最も低角側の回折ピークとして７．３°に回折ピークを有し、７．３°のピークと９．４°のピークの間にピークを有さず、更に２６．３°に回折ピークを有さないチタニルフタロシアニン結晶を得ることができた。

The X-ray diffraction spectrum of the precursor obtained by using the second organic solvent described in Table 1 was the same as the X-ray diffraction spectrum of the precursor of Example 1 (see FIG. 2). It was. That is, in Examples 2 to 7, the maximum diffraction at 27.2 ° as the diffraction peak (± 0.2 °) of the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα that is the target precursor. Having a major diffraction peak at 9.4 °, 9.6 °, 24.0 °, and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, A titanyl phthalocyanine crystal having no peak between the peak at 3 ° and the peak at 9.4 ° and further having no diffraction peak at 26.3 ° could be obtained.

  Moreover, the X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained by crystal conversion of the precursors of Examples 2 to 7 is the X-ray diffraction spectrum of the crystal 1 finally obtained in Example 1 (see FIG. 3), respectively. It was similar. That is, in Examples 2 to 7, the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, which is the target titanyl phthalocyanine crystal, is 26.2 ° at the maximum. It has a diffraction peak and is further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1. A titanyl phthalocyanine crystal having a diffraction peak at ° and 28.3 ° could be obtained (referred to as crystals 2-7).

(Example 8)
In Example 8, in the fourth step, crystal conversion with the first organic solvent was performed as follows to obtain a titanyl phthalocyanine crystal.

  40 g of the precursor synthesized in the third step of Example 1 was immersed in 400 g of tetrahydrofuran as the first organic solvent for 1 week in a dark place. One week later, the titanyl phthalocyanine crystal separated by filtration was vacuum-dried at 100 ° for 1 day to obtain the desired titanyl phthalocyanine crystal.

  The X-ray diffraction spectrum of the titanyl phthalocyanine crystal finally obtained in Example 8 was the same as the X-ray diffraction spectrum of the crystal 1 finally obtained in Example 1 (see FIG. 3). That is, in Example 8, the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, which is the target titanyl phthalocyanine crystal, is a maximum diffraction peak at 26.2 °. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, A titanyl phthalocyanine crystal having a diffraction peak at 28.3 ° could be obtained (referred to as crystal 8).

Example 9
In Example 9, in the fourth step, as a means for crystal conversion of the precursor, instead of crystal conversion with an organic solvent, crystal conversion by applying a mechanical shear force was used. A titanyl phthalocyanine crystal was synthesized in the same manner as in Example 1.

  That is, in Example 9, 40 g of the precursor of Example 1 was put into a ball mill pot with a diameter of 150 mm together with 3.5 kg of a zirconia ball with a diameter of 2 mm, and milled for 48 hours. After milling, it was fractionated from zirconia balls to obtain the desired titanyl phthalocyanine crystal.

  The X-ray diffraction spectrum of the titanyl phthalocyanine crystal finally obtained in Example 9 was the same as the X-ray diffraction spectrum of the crystal 1 finally obtained in Example 1 (see FIG. 3). That is, in Example 9, as the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, which is the target titanyl phthalocyanine crystal, the maximum diffraction peak at 26.2 ° 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, A titanyl phthalocyanine crystal having a diffraction peak at 28.3 ° could be obtained (referred to as crystal 9).

(Comparative Example 1)
In Comparative Example 1, a titanyl phthalocyanine crystal was synthesized in the same manner as in Example 1 except that 2-butanone was used in place of tetrahydrofuran as the second organic solvent in the third step.

  FIG. 4 is a diagram showing an example of an X-ray diffraction spectrum of the precursor obtained in Comparative Example 1. As is clear from FIG. 4, the precursor obtained in Comparative Example 1 is 27.2 ° as a diffraction peak with a Bragg angle 2θ (± 0.2 °) with respect to the Cu—Kα ray (wavelength 1.542 mm). Although it has the maximum diffraction peak, it has a diffraction peak at 7.5 ° as the lowest diffraction peak.

  To the precursor obtained in Example 1 and the precursor obtained in Comparative Example 1, 3% by mass of a pigment crystal prepared in the same manner as the pigment crystal described in JP-A-61-239248 was added, and a mortar To obtain a mixed powder. Each was measured for X-ray diffraction spectra under the same conditions as above.

  FIG. 5 shows an X-ray diffraction spectrum of the powder containing the precursor of Example 1, and FIG. 6 shows an X-ray diffraction spectrum of the powder containing the precursor of Comparative Example 1. In the spectrum of FIG. 5, it can be seen that there are two peaks at 7.3 ° and 7.5 ° on the low angle side, and at least the peaks at 7.3 ° and 7.5 ° are different. On the other hand, in the spectrum of FIG. 6, the low angle side peak exists only at 7.5 °, which is clearly different from the spectrum of FIG.

  FIG. 7 is a diagram showing an example of an X-ray diffraction spectrum of the titanyl phthalocyanine crystal finally obtained in Comparative Example 1. As is apparent from FIG. 7, the titanyl phthalocyanine crystal finally obtained in Comparative Example 1 has a diffraction peak of Bragg angle 2θ (± 0.2 °) with respect to the Cu—Kα ray (wavelength 1.542１．５) as 26 It has a maximum diffraction peak at 2 ° and is further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2. It has diffraction peaks at °, 27.1 °, and 28.3 ° (this is referred to as crystal 10). That is, the crystal 10 finally obtained in Comparative Example 1 was the same as the crystals 1-9 finally obtained in Examples 1-9 as the X-ray diffraction spectrum.

  Thus, the method for producing the titanyl phthalocyanine crystal of Comparative Example 1 has a diffraction peak on the lowest angle side of the Bragg angle 2θ (± 0.2 °) with respect to the Cu—Kα ray (wavelength 1.542α) as a precursor. It differs from the method for producing the titanyl phthalocyanine crystal of Examples 1 to 9 in that a titanyl phthalocyanine crystal having a diffraction peak at 7.5 ° was used.

(Comparative Example 2)
A titanyl phthalocyanine crystal was synthesized according to Production Example 1 of Patent Document 1.

  Specifically, 97.5 g of phthalodinitrile was added to 750 ml of α-chloronaphthalene, and then 22 ml of titanium tetrachloride was added dropwise under a nitrogen atmosphere. After dropping, the temperature was raised, and the mixture was reacted at 200 to 220 ° C. for 3 hours with stirring, then allowed to cool, filtered hot at 100 to 130 ° C., and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. The obtained cake of crude titanyl phthalocyanine was washed with 300 ml of α-chloronaphthalene and then with 300 ml of methanol at room temperature, and further washed with 800 ml of methanol for 1 hour with hot washing three times, and the resulting cake was added to 700 ml of water. Suspended and heat washed for 2 hours. The hot wash was repeated until the pH of the hot wash filtrate was approximately 7. Thereafter, an operation of carrying out hot washing for 2 hours in 700 ml of N-methylpyrrolidone at 140 to 145 ° C. was carried out four times. Subsequently, it was subjected to hot washing with 800 ml of methanol twice, filtered, and vacuum-dried at 80 ° C. for 1 day to obtain a titanyl phthalocyanine crystal (referred to as crystal 11).

  It was confirmed that the X-ray diffraction spectrum of the crystal 11 finally obtained in Comparative Example 2 was the same as that shown in FIG.

  As described above, the method for producing a titanyl phthalocyanine crystal of Comparative Example 2 is that Example 1 does not use a step of crystal conversion of a precursor having a specific X-ray diffraction spectrum, and uses titanium halide as a raw material. It differs from the manufacturing method of titanyl phthalocyanine crystal | crystallization of -9.

(Comparative Example 3)
A titanyl phthalocyanine crystal was synthesized according to Production Example 4 of Patent Document 1.

  Specifically, 46 g of phthalodinitrile was charged in 250 ml of α-chloronaphthalene and dissolved by heating. Then, 10 ml of titanium tetrachloride was added dropwise, stirred at 150 ° C. for 30 minutes, and then gradually heated to 220 ° C. And stirred for 2 hours. Thereafter, the mixture was allowed to cool with stirring, and when the temperature of the reaction system dropped to 100 ° C., it was filtered hot, then hot suspended in 600 ml of methanol and suspended in boiling with hot water once each, and then 600 ml of N -Hot suspending with methylpyrrolidone at 120 ° C for 1 hour, hot filtration, hot suspension with 800 ml of methanol, filtration and vacuum drying at 80 ° C for 1 day to obtain titanyl phthalocyanine crystals (this Crystal 12).

  It was confirmed that the X-ray diffraction spectrum of the crystal 12 finally obtained in Comparative Example 3 was the same as that in FIG.

  As described above, the method for producing a titanyl phthalocyanine crystal of Comparative Example 3 does not use a step of crystal conversion of a precursor having a specific X-ray diffraction spectrum, and uses a titanium halide as a raw material. It differs from the manufacturing method of titanyl phthalocyanine crystal | crystallization of -9.

(Application Examples 1-3, Comparative Application Examples 1-3)
An electrophotographic photoreceptor was prepared using the titanyl phthalocyanine crystal produced as described above, and the stability of the produced titanyl phthalocyanine crystal was evaluated by evaluating the electrostatic characteristics of the electrophotographic photoreceptor.

[Preparation of dispersion]
Dispersions 1 to 6 were prepared by mixing the titanyl phthalocyanine crystals shown in Table 2 with a binder resin and a solvent in the following proportions and dispersing them with zirconia balls having a diameter of 0.5 mm. A bead mill disperser (VMA-GETZMANN GMBH: DISPERMAT SL) was used for the preparation of the dispersion. After dispersing for 300 minutes at a rotor rotation speed of 3000 rpm, 2060 parts by weight of 2-butanone was added to the bead mill disperser in order to take out the dispersion from the bead mill disperser to prepare dispersions 1-6.

Titanyl phthalocyanine crystal (see Table 2) 48 parts by weight Polyvinyl butyral (manufactured by Sekisui Chemical: BX-1) 32 parts by weight 2-butanone 720 parts by weight

このように作製した分散液１〜６をそれぞれ乾燥させ、その乾燥体のＸ線回折スペクトルを測定したところ、分散前のチタニルフタロシアニン結晶のＸ線回折スペクトル（図３、図７等参照）と同様のものであった。したがって、本実施例の分散液によれば、本実施例のチタニルフタロシアニン結晶を安定状態で分散できることを確認できた。

Each of the dispersions 1 to 6 thus prepared was dried, and the X-ray diffraction spectrum of the dried product was measured. The same as the X-ray diffraction spectrum of the titanyl phthalocyanine crystal before dispersion (see FIGS. 3 and 7). It was a thing. Therefore, according to the dispersion liquid of this example, it was confirmed that the titanyl phthalocyanine crystal of this example could be dispersed in a stable state.

[Production of electrophotographic photosensitive member]
Electrophotographic photoreceptors 1 to 6 were produced using the dispersions 1 to 6 thus produced, respectively. That is, an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition were sequentially applied and dried on an aluminum plate (JIS 1050) having a thickness of 1 mm. Electrophotographic photoreceptors 1 to 6 comprising a pulling layer, a 0.2 μm charge generation layer, and a 25 μm charge transport layer were formed.
(Undercoat layer coating solution)
Titanium oxide (Ishihara Sangyo Co., Ltd .: CR-EL) 70 parts by weight Alkyd resin (Dainippon Ink Chemical Co., Ltd .:
Beckolite M6401-50-S, (solid content 50 mass%)) 15 parts by weight Melamine resin (Dainippon Ink & Chemicals, Inc .:
Superbecamine L-121-60, (solid content 60% by mass)) 10 parts by weight 2-butanone 100 parts by weight (charge generation layer coating solution)
Each of the above dispersions 1 to 6 was used.
(Charge transport layer coating solution)
Polycarbonate (Mitsubishi Gas Chemical Co., Ltd .: Iupilon Z300) 10 parts by weight Tetrahydrofuran 80 parts by weight 7 parts by weight of charge transport material having the following structural formula

［電子写真感光体の静電特性の評価］
このように作製した電子写真感光体１〜６を、静電複写紙試験装置（川口電機製、ＥＰＡ−８１００）を用いて、次のように評価した。

[Evaluation of electrostatic characteristics of electrophotographic photosensitive member]
The electrophotographic photoreceptors 1 to 6 thus produced were evaluated as follows using an electrostatic copying paper test apparatus (manufactured by Kawaguchi Electric, EPA-8100).

First, corona charging is performed at a discharge voltage of −6.3 kV for 20 seconds, and then dark decay is performed for 20 seconds. Next, 5 μW / cm ² light (tungsten lamp light passing through a band pass filter of 780 nm) was exposed for 20 seconds to attenuate the light.

  The surface potential (V20) after 20 seconds of charging and the surface potential (V40) after 20 seconds of dark decay were measured, and the ratio (V40 / V20) was determined. Further, the time during which the surface potential was attenuated by light from V40 to 1/10 of V40 by exposure was determined, and the photosensitivity was determined from the product of the exposure amount. These results are shown in Table 3.

  Further, after repeating the above charging and exposure for 30 minutes, the same measurement was performed to obtain the characteristics after fatigue. The results are shown in Table 3.

表３から明らかなように、応用例１〜３の電子写真感光体１〜３では、疲労後の帯電性が良好であることが確認できた。これに対し、比較応用例１〜３の電子写真感光体４〜６では、疲労後の帯電性が良くなかった。

As is apparent from Table 3, it was confirmed that the electrophotographic photoreceptors 1 to 3 of the application examples 1 to 3 have good chargeability after fatigue. On the other hand, in the electrophotographic photoreceptors 4 to 6 of Comparative Application Examples 1 to 3, the chargeability after fatigue was not good.

  When the electrophotographic photoreceptors 1 to 3 of the application examples 1 to 3 and the electrophotographic photoreceptor 4 of the comparative application example 1 are compared, they are manufactured in the same manner except that the kind of the titanyl phthalocyanine crystal is different. Therefore, when these titanyl phthalocyanine crystals are compared, the crystals 1, 8, 9 used in Application Examples 1 to 3 and the crystal 10 used in Comparative Application Example 1 are the same as the X-ray diffraction spectrum. There are different X-ray diffraction spectra of the precursors.

  Therefore, even if the same titanyl phthalocyanine crystal is used as an X-ray diffraction spectrum, an electrophotographic photosensitive material having excellent charging stability upon repeated use can be obtained by using a titanyl phthalocyanine crystal obtained by crystal conversion of a specific precursor. It turns out that the body can be provided. That is, even if the same titanyl phthalocyanine crystal as the X-ray diffraction spectrum, it was confirmed that the titanyl phthalocyanine crystal obtained by crystal conversion of a specific precursor was excellent in crystal stability.

  Thus, according to the method for producing a titanyl phthalocyanine crystal of this example, at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα. Has a maximum diffraction peak, 9.4 °, 9.6 °, and 24.0 °, the main diffraction peak, and the lowest diffraction peak at 7.3 °. In addition, by converting the titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° and not having the diffraction peak at 26.3 °, the characteristics of CuKα As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to X-rays (wavelength 1.542Å), it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 °, and 13. 2 °, 15.1 °, 15.6 °, 16.1 °, A titanyl phthalocyanine crystal having diffraction peaks at 20.7 °, 23.2 °, 27.1 °, and 28.3 ° and excellent in crystal stability can be obtained.

2 is a diagram showing an example of an X-ray diffraction spectrum of amorphous titanyl phthalocyanine obtained in Example 1. FIG. 2 is a diagram showing an example of an X-ray diffraction spectrum of a precursor obtained in Example 1. FIG. 2 is a diagram showing an example of an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained by crystal conversion of the precursor of Example 1. FIG. 6 is a diagram showing an example of an X-ray diffraction spectrum of a precursor obtained in Comparative Example 1. FIG. It is the figure which showed an example of the X-ray-diffraction spectrum of the mixed powder (mass ratio 97: 3) of the precursor of Example 1, and the pigment crystal described in Unexamined-Japanese-Patent No. 61-239248. It is the figure which showed an example of the X-ray-diffraction spectrum of the mixed powder (mass ratio 97: 3) of the precursor of the comparative example 1, and the pigment crystal described in Unexamined-Japanese-Patent No. 61-239248. 4 is a diagram showing an example of an X-ray diffraction spectrum of a titanyl phthalocyanine crystal finally obtained in Comparative Example 1. FIG.

Claims (6)

As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 ° Of titanyl phthalocyanine crystals having diffraction peaks at 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, 28.3 ° A method,
An amorphous titanyl phthalocyanine having a maximum diffraction peak at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542１．５) of CuKα is In the presence, obtained by crystal conversion with an organic solvent containing at least one organic solvent selected from tetrahydrofuran, cyclohexane, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane. Was
As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, it has a maximum diffraction peak at least 27.2 °, and further 9.4 ° and 9.6 °. , Having a main diffraction peak at 24.0 ° and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, between the 7.3 ° peak and the 9.4 ° peak A method for producing a titanyl phthalocyanine crystal characterized by using a titanyl phthalocyanine crystal having no peak and further having no diffraction peak at 26.3 °, and further performing a second crystal conversion. The method for producing a titanyl phthalocyanine crystal according to claim 1, wherein the second crystal conversion is performed by a treatment with a first organic solvent.   3. The method for producing a titanyl phthalocyanine crystal according to claim 2, wherein the first organic solvent includes at least one organic solvent selected from a ketone solvent and an ether solvent. The titanyl phthalocyanine crystal according to any one of claims 1 to 3 , wherein the half-width of the maximum diffraction peak of 7.0 to 7.5 ° of the amorphous titanyl phthalocyanine is 1 ° or more. Manufacturing method. The method for producing a titanyl phthalocyanine crystal according to any one of claims 1 to 4, wherein the amorphous titanyl phthalocyanine is synthesized without using a titanium halide. The titanyl phthalocyanine crystal manufactured with the manufacturing method of the titanyl phthalocyanine crystal as described in any one of Claims 1-5 .

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