JP2973055B2 - Titanyl phthalocyanine crystal dispersion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dispersion of a titanyl phthalocyanine pigment. Especially used for printers, etc.
The present invention relates to a dispersion of an electrophotographic photosensitive member material that is effective for LED light and semiconductor laser light.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable development of electronic equipment, and there is an increasing demand for printers and digital copiers used for output from computers. These devices require a photoconductor that is sensitive to red to near-infrared light because a semiconductor laser or LED is used as a light source.

Conventional inorganic photoconductors such as selenium are not sufficient for this purpose, and many organic photoconductors (OPC) in which phthalocyanines are dispersed have been studied.

It is known that phthalocyanines have different photoelectron characteristics depending on their crystal forms.
Y-type titanyl phthalocyanine, which has a peak at 9.6 degrees, is an excellent material having a high photon efficiency of 0.94 (Japan Hardcopy 89, Proceedings 103, (1989)). However, this material has the disadvantage that the sensitivity is somewhat affected by humidity. There are several ideas for this cause. While studying the excellent physical properties of the Y-type crystal, Fujimaki et al. Found that the photon efficiency of the material was reduced by heating or reversible dehydration treatment in a dry nitrogen atmosphere. This is because when water is reabsorbed at room temperature and humidity, it recovers again, so the Y-type particles are water-adsorbed crystals, and assist the dissociation of holes and photoelectrons from the titanyl phthalocyanine exciton generated by the exposure of water molecules to light. I do. It is speculated that this is one of the causes of the high sensitivity of Y-type titanyl phthalocyanine and the cause of the decrease in sensitivity at low humidity (Y. Fujimaki: IS &T's 7th International Cong)
ress on Advance in Nonimpact Printing Technologie
s, Paper Summaries, 269, (1991)). From this idea, it is expected that a similar effect can be obtained by adding a compound having an OH group instead of water. We are 1,2-butanediol,
Amorphous titanyl phthalocyanine was subjected to crystal transformation in the presence of a compound having an adjacent OH group such as 1,2-hexanediol and 1,2-cyclohexanediol to obtain a desired titanyl phthalocyanine adduct.

[0005] These products gave, as expected, excellent photosensitive members having high sensitivity and no humidity dependency. However,
These crystals are stable in a powder or a completed photoreceptor without a solvent, but are not stable crystals in a dispersion, and when stored in a dispersion for a long time, other crystal forms are mixed. There is a problem that performance deteriorates. When the photosensitive drum is manufactured by a technique such as spray coating at the research stage, there is no problem because most of the dispersion is consumed. However, in the future, in the current dip (dipping) coating, only a very small part of the coating liquid will be attached to and removed from the drum, and the storability of the remaining coating liquid will account for a large proportion of the manufacturing cost. .

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a stable coating solution of titanyl phthalocyanine crystal having good sensitivity and low humidity dependency in view of the above-mentioned circumstances, and to provide a photoreceptor having a low cost. .

[0007]

The object of the present invention has been achieved by adding a compound having an adjacent OH group to a dispersion of a specific titanyl phthalocyanine crystal. The specific titanyl phthalocyanine crystal is an adduct with a compound containing adjacent OH (hereinafter, adjacent diol compound). The addition is apparent from the thermal analysis (TG) of the titanyl phthalocyanine crystal, in which a weight loss is observed at a temperature higher than the boiling point by 100 ° C. or more, and the adjacent OHs are released. From the weight reduction, adjacent diol compound / titanyl phthalocyanine = 1/2.

Examples of the titanyl phthalocyanine adduct of the adjacent diol compound of the present invention include, but are not limited to, the following.

In the following, adjacent diol compounds, crystal type names,
The 2θ peaks in the X-ray diffraction spectrum were listed as a set. The following tentative names were used for the crystal type names for the sake of organization.

Adjacent diol compound Crystalline X-ray diffraction peak (degree) 1,2-butanediol N1 type 9.6, 12.6, 16.1, 26.3 N2 type 9.0, 9.3, 14.0, 16.3, 26.2 2,3-butanediol P type 8.4 , 9.5, 15.2, 19.0, 26.3 1,2-hexanediol R1 type 7.1, 7.9, 26.0 R2 type 7.2, 13.9, 24.3, 27.4 1,2-cyclohexanediol U type 7.7, 12.2, 16.1, 16.4, 18.7, 19.3 26.0 Examples of the adjacent diol compound having 4 or more carbon atoms of the present invention include methoxypropanediol and diglycerin in addition to the above.

The above X-ray diffraction spectrum was measured under the following conditions.

X-ray tube Cu voltage 40.0 kv Current 100 mA Start angle 6.00 deg. Stop angle 35.00 deg. Step angle 0.020 deg. Measurement time 0.50 sec. The dispersion of the present invention is a dispersion of these adducts of titanyl phthalocyanine with diol compounds. In some cases, the diol compound is added to a liquid to improve the stability. The addition amount of the diol compound may be as much as 0.01% based on the total solvent, preferably
0.1 to 5%. As will be described in the examples, there is a remarkable stabilizing effect. That is, the diol compound adduct of titanyl phthalocyanine is in a metastable state and is in an equilibrium state as shown in the following formula in the dispersion.

[0013] TiOPc adduct ⇔ TiOPc + diol compound When a small amount of a diol compound is added to this system, the equilibrium is considered to shift to the left.

A polymer binder can be used in the dispersion of the present invention. Examples of the binder include polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, and vinyl chloride. -Vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-
Examples include formaldehyde resin, styrene-acrylic copolymer resin, styrene-alkyd resin, poly-N-vinylcarbazole, polyvinylbutyral resin, polycarbonate Z resin, ethylcellulose resin, nitrocellulose resin, and polyvinyl alcohol resin. These binders can be used alone or as a mixture of two or more. Examples of the solvent used for the dispersion include acetone, methyl ethyl ketone, cyclohexanone, toluene, dichlorobenzene, dichloromethane, dichloroethane, tetrahydrofuran, dioxane, methanol, ethanol, isopropanol, ethyl acetate, butyl acetate and the like. As a means for preparing the dispersion, a well-known means such as a sand grinder, a ball mill, and ultrasonic waves can be used.

[0015]

EXAMPLES The synthesis examples and examples are described below.

(Synthesis Example 1; Synthesis of N2-Type TiOPc Crystal) (Synthesis of TiOPc-Amorphous Product) 1,3 diiminoisoindoline; 29.2 g; ortho-dichlorobenzene 200 ml
And 20.4 g of titanium tetra-n-butoxide was added, and the mixture was heated at 150 to 160 ° C. for 5 hours under a nitrogen atmosphere. After standing to cool, the precipitated crystals were filtered and washed with chloroform, 2%
After washing with an aqueous hydrochloric acid solution, washing with water, and washing with methanol, 26.2 g (91.0%) of crude titanyl phthalocyanine was obtained after drying.
Its crystal form is shown in FIG. Then, 20.0 g of the crude titanyl phthalocyanine was added in 200 ml of concentrated sulfuric acid at 5 ° C. or lower.
Stir for hours to dissolve and pour into 4 l of water at 20 ° C.
The precipitated crystals were filtered and sufficiently washed with water to obtain 180 g of a wet paste product. The dried and powdered crystal form is in an amorphous state as shown in FIG.

(Preparation of N2 Type TiOPc Crystal of the Present Invention)
Take 100 ml of ortho-dichlorobenzene and 50 ml of 1,2-butanediol into a flask and add the chlor-free TiO
8 g of Pc-amorphous dry powder was added. The mixture was then stirred at 70 ° C. for 10 hours. Then, the mixture was poured into methanol (800 ml) to precipitate crystals. After filtration, washing with methanol and drying, 8.4 g of the desired titanyl phthalocyanine crystal was obtained. As shown in FIG. Bragg angle 2
θ; peaks at 9.0, 9.3, 14.0, 16.3, 26.2 (N
2 type crystal).

(Synthesis Example 2; Synthesis of P-type TiOPc) 100 ml of orthodichlorobenzene and 50 ml of 2,3-butanediol were placed in a flask, and 8 g of titanyl phthalocyanine-amorphous dry powder obtained by the method of Synthesis Example 1 was added thereto. added. The mixture was then heated at reflux for 7 hours. After cooling, the mixture was poured into methanol (800 ml) to precipitate crystals. After filtration, washing with methanol and drying, 8.4 g of the desired titanyl phthalocyanine crystal was obtained. As shown in FIG. It is a crystal (P-type crystal) having peaks at Bragg angles 2θ; 8.4, 9.5, 15.2, 19.0, 26.3.

(Synthesis Example 3; Synthesis of R1 type TiOPc) 100 ml of ortho-dichlorobenzene and 50 ml of 1,2-hexanediol were placed in a flask, and 8 g of titanyl phthalocyanine-amorphous dry powder obtained by the method of Synthesis Example 1 was added thereto. Was. The mixture was then heated at 70 ° C. for 5 hours. After cooling, the mixture was poured into methanol (800 ml) to precipitate crystals. After filtration, washing with methanol and drying, 8.4 g of the desired titanyl phthalocyanine crystal was obtained. As shown in FIG. It is a crystal (R1-type crystal) having peaks at Bragg angles 2θ; 7.1, 7.9, and 26.0.

(Synthesis Example 4; Synthesis of R2 type TiOPc) 100 ml of orthodichlorobenzene and 50 ml of 1,2-hexanediol were placed in a flask, and 8 g of the titanyl phthalocyanine-amorphous dry powder obtained by the method of Synthesis Example 1 was added thereto. Was. The mixture was then heated at reflux for 6 hours. After cooling, the mixture was poured into methanol (800 ml) to precipitate crystals. After filtration, washing with methanol and drying, 8.4 g of the desired titanyl phthalocyanine crystal was obtained. As shown in FIG. It is a crystal (R2-type crystal) having peaks at Bragg angle 2θ; 7.2, 13.9, 24.3, 27.4.

(Synthesis Example 5; Synthesis of U-type TiOPc) 100 ml of orthodichlorobenzene and 50 ml of 1,2-cyclohexanediol were placed in a flask, and 8 g of titanyl phthalocyanine-amorphous dry powder obtained by the method of Synthesis Example 1 was added thereto.
Was added. The mixture was then heated at reflux for 6 hours.
After cooling, the mixture was poured into methanol (800 ml) to precipitate crystals. After filtration, washing with methanol and drying, 8.4 g of the desired titanyl phthalocyanine crystal was obtained. As shown in FIG. Bragg angle 2θ; 7.7, 12.2, 16.1, 16.4, 18.7, 1
It is a crystal (U-type crystal) having peaks at 9.3 and 26.0.

Example 3 parts of the titanyl phthalocyanine N2 type crystal of the present invention obtained in Synthesis Example 1, 20 parts of a silicone resin (“KR-5240, 15% xylene butanol solution” manufactured by Shin-Etsu Chemical Co., Ltd.), and 100 parts of methyl ethyl ketone (wt) Was pulverized and dispersed by a sand grinder to obtain a dispersion. To this was added 0.5 parts of 1,2-butanediol. (Sample 1) Similarly, a dispersion was obtained using the titanyl phthalocyanine P-type crystal of the present invention obtained in Synthesis Example 2, and 0.5 part of 2,3-butanediol was added thereto. (Sample 2) Similarly, a dispersion was obtained using the titanyl phthalocyanine R1 type crystal of the present invention obtained in Synthesis Example 3, and 0.5 part of 1,2-hexanediol was added thereto. (Sample 3) Similarly, a dispersion was obtained using the titanyl phthalocyanine R2 type crystal of the present invention obtained in Synthesis Example 4, and 0.5 part of 1,2-hexanediol was added thereto. (Sample 4) Similarly, a dispersion was obtained using the titanyl phthalocyanine R1 type crystal of the present invention obtained in Synthesis Example 3, and 0.5 part of 1,2-cyclohexanediol was added thereto. (Sample 5) These dispersions of the present invention were subjected to a forced deterioration test for 16 weeks in a constant temperature box at 40 ° C. together with a comparative dispersion containing no diols.

These dispersions were applied to a slide glass and the X-ray diffraction spectrum was measured.

The results are shown in FIGS. While the dispersion to which the diols of the present invention are added does not change, the crystal form of the comparative dispersion to which no diols are added is changing. Reference Example A dispersion liquid which was not compared with the dispersion liquid to which the diol compound of the present invention of the present invention was added was applied to an electrophotographic photoreceptor, and was prepared on a photoreceptor immediately after dispersion and after a forced deterioration test, and subjected to comparative evaluation.
That is, the titanyl phthalocyanine crystal dispersions of Synthesis Examples 1 to 5 and a comparative dispersion in which no adjacent diol compound was added were applied to an aluminum-evaporated polyester base to form a carrier-generating layer having a thickness of 0.2 μm. on the other hand,
1 part of the following carrier transporting substance (1), 2 parts (wt) of a polycarbonate resin ("Iupilon Z200" manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 0.01 part of silicone oil ("KF-54" manufactured by Shin-Etsu Chemical Co., Ltd.) in 1,2-dichloroethane This was dissolved in 15 parts (wt), and this was coated on the carrier generation layer with a blade to form a carrier transport layer having a dry film thickness of 25 μm, thereby producing a photoreceptor.

[0025]

Embedded image

The photoreceptor prepared immediately after dispersion and the photoreceptor after the forced deterioration test were evaluated and compared for each dispersion.

Evaluation: Each sample was evaluated using a paper analyzer EPA-8100 (manufactured by Kawaguchi Electric Co., Ltd.). It is charged for 5 seconds under a discharge condition of -80 μA, and the surface potential [Va] immediately after the charging and the surface potential [V] after being left in the dark for 5 seconds.
i], exposure is performed so that the surface illuminance becomes 2 (lux), and the exposure amount [E1 / 6 (lux.s
ec)]. Further equation: D = (Va−Vi) / Va
The decay rate [D (%)] of the potential in a dark place was determined by × 100. The results are shown below. Va E1 / 6 D Photoreceptor sample 1 Prepared immediately after dispersion 1560 0.85 5.2% Comparative photoreceptor sample 1 Prepared immediately after dispersion 1540 0.80 5.2% Photoreceptor sample 1 After forced degradation test 1550 0.86 5.1% Comparative photoreceptor sample 1 After forced degradation test 1510 0.95 9.0 In contrast to the dispersion of the present invention to which the adjacent diol compound was added, the electrophotographic performance hardly changed immediately after dispersion or after the forced deterioration test, whereas the comparative dispersion without the diol compound added after the forced deterioration test, D greatly increases.

[0028]

According to the present invention, a stable coating solution of titanyl phthalocyanine crystal having high sensitivity and low humidity dependency can be provided, and a photoreceptor having a low cost can be provided.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction spectrum of crude titanyl phthalocyanine used in the synthesis of titanyl phthalocyanine of the present invention.

FIG. 2 is an X-ray diffraction spectrum of amorphous-titanyl phthalocyanine.

FIG. 3 is an X-ray diffraction spectrum of an N2-type titanyl phthalocyanine crystal.

FIG. 4 is an X-ray diffraction spectrum of a P-type titanyl phthalocyanine crystal.

FIG. 5 is an X-ray diffraction spectrum of an R1-type titanyl phthalocyanine crystal.

FIG. 6 is an X-ray diffraction spectrum of an R2-type titanyl phthalocyanine crystal.

FIG. 7 is an X-ray diffraction spectrum of a U-type titanyl phthalocyanine crystal.

FIG. 8 shows raw samples of Sample 1 and Comparative Sample (1),
The X-ray diffraction spectrum figure of a forcibly deteriorated sample.

FIG. 9 shows raw samples of Sample 2 and Comparative Sample (2),
The X-ray diffraction spectrum figure of a forcibly deteriorated sample.

FIG. 10 is an X-ray diffraction spectrum of a raw sample and a forcedly degraded sample of Sample 3 and Comparative Sample (3).

FIG. 11 is an X-ray diffraction spectrum of a raw sample and a forcedly degraded sample of Sample 4 and Comparative Sample (4).

FIG. 12 is an X-ray diffraction spectrum of a raw sample and a forcedly degraded sample of Sample 5 and Comparative Sample (5).

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-273775 (JP, A) JP-A-5-273776 (JP, A) JP-A-5-273774 (JP, A) JP-A-5-273774 313389 (JP, A) JP-A-3-26961 (JP, A) JP-A-4-159373 (JP, A) JP-A-4-324450 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09B 67/50 C09B 67/20 G03G 5/06 371

Claims (2)

(57) [Claims] 1. A dispersion of titanyl phthalocyanine crystals to which a compound having 4 or more carbon atoms having adjacent OH (adjacent diol compound) is added. 2. A titanyl phthalocyanine adduct, wherein the compound having an adjacent OH is 1,2-butanediol, 2,3-butanediol, 1,2-cyclohexanediol, or 1,2-hexanediol. Dispersion.