Process for producing crystalline I-type oxytitanium phthalocyanine

Abstract

The present invention relates to a process for producing a crystalline I-type oxytitanium phthalocyanine having strong peaks in CuK.alpha. characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 9.0.degree., 14.2.degree., 23.9.degree., and 27.1.degree., comprising milling-treatment of oxytitanium phthalocyanine or an aqueous paste thereof with a solvent containing a saturated hydrocarbon solvent.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for producing crystalline oxytitanium phthalocyanine. More particularly, the present invention relates to a process for producing crystalline oxytitanium phthalocyanine of type-I which shows strong peaks in CuK.alpha. characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 9.0.degree., 14.2.degree., 23.9.degree., and 27.1.degree..

2. Related Background Art

Phthalocyanine pigments have come to be employed extensively as catalysts, electrophotographic sensitive members, solar batteries, sensors, etc., as well as in conventional uses for coloration of paints, inks, resins, and the like.

Among the phthalocyanine pigments, oxytitanium phthalocyanine is known to have excellent characteristics for an electrophotographic material. The characteristics vary depending on the crystal form of the oxytitanium phthalocyanine. A variety of crystal forms of oxytitanium phthalocyanine are obtained depending on the minute differences of production conditions.

Oxytitanium phthalocyanines having different crystal structures produced under various production conditions were described, for example, in JP-A Sho-59-49544 (U.S. Pat. No. 4,444,861)("JP-A" refers to Japanese Patent Application Laid-Open No.), JP-A Sho-59-166959, JP-A Sho-61-239248 (U.S. Pat. No. 4,728,592), JP-A 62-67094 (U.S. Pat. No. 4,664,997), JP-A Sho-63-366, JP-A 63-116158, JP-A Sho-63-198067, JP-A Sho-64-17066, and so forth. The crystal forms described in the above patent publications, however, are obtained usually as a mixture, which involves difficulty in uniformity of the quality of the products. Accordingly, a method has been desired which gives a pure crystal form of oxytitanium phthalocyanine and many attempts have been made therefor. Processes for production of A-type or C-type crystal are described, for example, in JP-A Sho-63-364, JP-A Sho-63-365, JP-A Sho-63-37163, JP-A Sho-63-57670, JP-A Sho-63-80263, and so forth.

It is described in Japanese Patent Application No. Hei-1-189200 that the oxytitanium phthalocyanine is a crystal form having strong peaks at Bragg angles (2.theta..+-.0.2.degree.) of 9.0.degree., 14.2.degree., 23.9.degree., and 27.1.degree. in CuK.alpha. characteristic X-ray diffraction. Specifically I-type oxytitanium phthalocyanine, has excellent characteristics for electrophotographic sensitive materials. Although the I-type oxytitanium phthalocyanine can be readily prepared in laboratories according to the preparation method described in the specification of the above patent application, the process is not sufficiently satisfactory regarding the employed solvents, from the standpoint of industrial production. For example, regarding the solvent used in the milling treatment, the ether type solvents are flammable, and further may be explosive if peroxide is formed; the monoterpene type solvents are not readily available for general use; and the liquid paraffin requires a long time for the treatment and is not easy to handle because of its high viscosity.

SUMMARY OF THE INVENTION

The present invention intends to provide a process for producing I-type oxytitanium phthalocyanine in a pure form.

The present invention further intends to provide a process for producing I-type oxytitanium phthalocyanine, which is suitable for industrialization and allows mass-production thereof in a simple process.

The present invention provides a process for producing I-type crystalline oxytitanium phthalocyanine which shows strong peaks in CuK.alpha. characteristic X-rays diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 9.0.degree., 14.2.degree., 23.9.degree. and 27.1.degree., comprising milling-treatment of oxytitanium phthalocyanine or an aqueous paste thereof with a solvent containing a saturated hydrocarbon solvent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an X-ray diffraction pattern of I-type oxytitanium phthalocyanine.

FIG. 2 is an X-ray diffraction pattern of M-type oxytitanium phthalocyanine.

FIG. 3 is an X-ray diffraction pattern of Mc-type oxytitanium phthalocyanine.

FIG. 4 is an X-ray diffraction pattern of B-type oxytitanium phthalocyanine.

FIG. 5 is an X-ray diffraction pattern of A-type oxytitanium phthalocyanine.

FIG. 6, FIG. 7, and FIG. 8 are respectively X-ray patterns of dried matter of the aqueous paste (1), the aqueous paste (2), or the aqueous paste (3).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The X-ray diffraction pattern (employing CuK.alpha. characteristic X-ray) of I-type crystal of the oxytitanium phthalocyanine produced according to the present invention has strong peaks at the Bragg angles (2.theta..+-.0.2.degree.) of 9.0.degree., 14.2.degree., 23.9.degree., and 27.1.degree.. These are the strongest four peaks, and are the main peaks.

The structure of the oxytitanium phthalocyanine is represented by the formula below: ##STR1## where X.sub.1, X.sub.2, X.sub.3, and X.sub.4 denote respectively Cl, or Br, and n, m, l, and k denote respectively an integer of from 0 to 4.

In the present invention, in the case where an aqueous paste oxytitanium phthalocyanine is not employed, the preferable oxytitanium phthalocyanine is of type M having main peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.2.degree., 14.2.degree., 24.0.degree., and 27.2.degree. in CuK.alpha. characteristic X-ray diffraction as shown in FIG. 2, or type Mc having main peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.1.degree., 10.4.degree., and 27.3.degree. in CuK.alpha. characteristic X-ray diffraction as shown in FIG. 3. The milling treatment of either M-type oxytitanium phthalocyanine or Mc-type oxytitanium phthalocyanine similarly gives I-type crystalline oxytitanium phthalocyanine, so that the mixture of the M-type and the Mc-type may be employed without any problem.

In the present invention, in the case where an aqueous paste of oxytitanium phthalocyanine is employed, the paste is preferably derived by a conventional acid-pasting method. This aqueous paste needs to uniformly contain water. The preferable solid content is within the range of from 15% to 45% by weight. The crystal form of the oxytitanium phthalocyanine used in the aqueous paste is not specially limited. The oxytitanium phthalocyanine contained in the aqueous paste takes on various forms, such as a slightly amorphous crystal forms or an amorphous form, depending on the conditions of the acid pasting treatment such as the amount of sulfuric acid, the amount of water, and the treatment temperature. However, any of the amorphous forms, as for example, a slightly amorphous crystal form and their mixtures may be used, provided that they have been subjected to an acid-pasting treatment.

The saturated hydrocarbon solvent for the dispersing medium for the milling treatment preferably includes aliphatic saturated hydrocarbon solvents having a main chain of 5 to 12 carbons in the molecule, which may have a methyl group in 2-position, such as n-pentane, n-hexane, n-octane, n-decane, n-dodecane, 2-methylpentane, 2-methyloctane, and the like. A mixed solvent containing the above-mentioned solvent as the main component may also be used, for example, solvents such as ligroin, petroleum benzin and the like.

The amount of the dispersion solvent may be arbitrarily selected. Preferably the amount is within the range of from 5 to 40 parts by weight based on 1 part of oxytitanium phthalocyanine. With a lesser amount of the solvent, the viscosity of the treating liquid becomes high, which prevents uniform treatment. In contrast, with a larger amount of the solvent, the amount of treated material in a unit volume is decreased, which lowers the productivity.

For the dispersion in the milling process of the present invention ordinary media can be used such as glass beads, steel beads, aluminum beads, and the like.

The treatment time is preferably not less than one hour, particularly preferable within the range of from 5 hours to 30 hours. The treatment time of less than one hour may cause the incomplete conversion of the crystal, while the treatment time exceeding 30 hour is not desirable in view of loss of productivity.

Although the treatment temperature is not particulary defined, the temperature is preferably not higher than 80.degree. C. in view of stability of the crystal.

The present invention is described more specifically, referring to Examples and Reference examples.

EXAMPLE 1

To 2.0 kg of M-type low-crystalline oxytitanium phthalocyanine, 40 kg of n-hexane was added. The mixture was subjected to milling treatment by use of glass beads of 1 mm in diameter at room temperature for 15 hours. The solid matter was separated from the liquid dispersion. The solid matter was then washed sufficiently with methanol and subsequently with deionized water and dried to give I-type crystalline oxytitanium phthalocyanine in a yield of 1.9 kg.

EXAMPLES 2-13, AND REFERENCE EXAMPLES 1-10

The same treatment as in Example 1 was conducted except that the crystal form of the starting oxytitanium phthalocyanine, the treatment solvent, and the treatment time were changed. The results are shown in Table 1 and Table 2.

The B-type and A-type crystalline oxytitanium phthalocyanines shown in Table 2 as the starting materials were prepared respectively according to preparation examples disclosed in JP-A Sho-61-239248 (U.S. Pat. No. 4,728,592), or JP-A Sho-62-67094 (U.S. Pat. No. 4,664,997). The X-ray diffraction patterns thereof are shown respectively in FIG. 4 and FIG. 5.

TABLE 1__________________________________________________________________________Example Crystal form of starting Treatment Treatment Crystal form of resultingNo. oxytitanium phthalocyanine solvent time oxytitanium phthalocyanine__________________________________________________________________________1 Type M n-Hexane 15 hours Type I2 Type M n-Octane 15 hours Type I3 Type M 2-methylpentane 15 hours Type I4 Type M 2-methyloctane 15 hours Type I5 Type Mc n-Hexane 20 hours Type I6 Type Mc n-Decane 20 hours Type I7 Type Mc n-Dodecane 20 hours Type I8 Type Mc 2-methyloctane 20 hours Type I9 Mixture of Type-M 50% n-Hexane 20 hours Type I and Type-Mc 50%10 Mixture of Type-M 50% n-Octane 20 hours Type I and Type-Mc 50%11 Mixture of Type-M 80% n-Hexane 20 hours Type I and Type-Mc 20%12 Mixture of Type-M 80% n-Decane 20 hours Type I and Type-Mc 20%13 Mixture of Type-M 80% Ligroin 20 hours Type I and Type-Mc 20%__________________________________________________________________________ TABLE 2__________________________________________________________________________Reference Crystal form of starting Treatment Treatment Crystal form of resultingExample No. oxytitanium phthalocyanine solvent time oxytitanium phthalocyanine__________________________________________________________________________1 Type B n-Hexane 15 hours Type B2 Type A n-Hexane 15 hours Type A3 Type B n-Octane 20 hours Type B4 Type A n-Octane 20 hours Type A5 Type B n-Decane 20 hours Type B6 Type A n-Decane 20 hours Type A7 Type B 2-Methyloctane 20 hours Type B8 Type A 2-Methyloctane 20 hours Type A9 Type B 2-Methyloctane 20 hours Type B10 Type A 2-Methyloctane 20 hours Type A__________________________________________________________________________

EXAMPLE 14

Crystalline oxytitanium phthalocyanine which is generally called type B was prepared according to the preparation example disclosed in JP-A Sho-61-39248 (U.S. Pat. No. 4,728,592). 2.0 kg of this B-type crystalline matter was gradually added into 60 kg of concentrated sulfuric acid at a temperature of not higher than 5.degree. C., and was dissolved therein. The solution was added dropwise into 600 kg of ice water over 2 hours. The resulting pigment was collected by filtration and washed with water to prepare an aqueous paste of oxytitanium phthalocyanine (hereinafter referred to as "Aqueous paste (1)"). The solid content of this aqueous paste was 20%.

A portion of this aqueous paste was dried and subjected to X-ray diffraction measurement. The X-ray diffraction pattern is shown in FIG. 6.

n-hexane (20 kg) was added to 5.0 kg of Aqueous paste (1), and the mixture was subjected to milling treatment with glass beads of 1 mm in diameter at 20.degree. C. for 20 hours. The solid matter was separated from this liquid dispersion, and was washed sufficiently with n-hexane and dried to give I-type crystalline oxytitanium phthalocyanine in a yield of 0.9 kg.

EXAMPLES 15-23

The treatment was conducted in the same manner as in Example 1 except that the treatment solvent, the treatment time, and the treatment temperature were changed. The results are shown in Table 3.

TABLE 3__________________________________________________________________________Example Starting oxytitanium Treatment Treatment Treatment ResultingNo. phthalocyanine solvent temperature (.degree.C.) time (hours) crystal form__________________________________________________________________________14 Aqueous paste (1) n-Hexane 20 20 Type I15 Aqueous paste (1) n-Octane 20 20 Type I16 Aqueous paste (1) n-Decane 20 20 Type I17 Aqueous paste (1) n-Octane 50 15 Type I18 Aqueous paste (1) n-Dodecane 50 15 Type I19 Aqueous paste (1) n-Dodecane 70 10 Type I20 Aqueous paste (1) 2-Methylpentane 50 15 Type I21 Aqueous paste (1) 2-Methyloctane 50 20 Type I22 Aqueous paste (1) Ligroin 20 20 Type I23 Aqueous paste (1) Petroleum benzine 20 20 Type I__________________________________________________________________________

EXAMPLE 24

2.0 kg of the B-type oxytitanium phthalocyanine used in Example 14 was gradually added into 60 kg of concentrated sulfuric acid at a temperature of not higher than 5.degree. C., and was dissolved therein. The solution was added dropwise into 800 kg of water at 25.degree. C. in one hour. The resulting pigment was collected by filtration and washed with water to prepare an aqueous paste of oxytitanium phthalocyanine (hereinafter referred to as "Aqueous paste (2)"). The solid content of this aqueous paste was 24%.

A portion of this aqueous paste was dried and subjected to X-ray diffraction measurement. The X-ray diffraction pattern is shown in FIG. 7.

n-hexane (20 kg) was added to 4.2 kg of Aqueous paste (2), and the mixture was subjected to milling treatment with glass beads of 1 mm in diameter at 20.degree. C. for 20 hours. The solid matter was separated from this liquid dispersion, and was washed sufficiently with n-hexane and dried to give I-type crystalline oxytitanium phthalocyanine in a yield of 0.9 kg.

EXAMPLES 25-31

The treatment was conducted in the same manner as in Example 9 except that the treatment solvent, the treatment time, and the treatment temperature were changed. The results are shown in Table 4.

TABLE 4__________________________________________________________________________Example Starting oxytitanium Treatment Treatment Treatment ResultingNo. phthalocyanine solvent temperature (.degree.C.) time (hours) crystal form__________________________________________________________________________24 Aqueous paste (2) n-Hexane 20 20 Type I25 Aqueous paste (2) n-Octane 20 20 Type I26 Aqueous paste (2) n-Decane 20 20 Type I27 Aqueous paste (2) n-Octane 20 15 Type I28 Aqueous paste (2) n-Dodecane 50 15 Type I29 Aqueous paste (2) n-Dodecane 70 10 Type I30 Aqueous paste (2) 2-Methylpentane 50 15 Type I31 Aqueous paste (2) 2-Methyloctane 50 20 Type I__________________________________________________________________________

EXAMPLE 32

A-type oxytitanium phthalocyanine was prepared according to preparation example disclosed in JP-A Sho-62-67094 (U.S. Pat. No. 4,664,997). 2.0 kg of this A-type oxytitanium phthalocyanine was gradually added into 80.0 kg of concentrated sulfuric acid at a temperature of 30.degree. C. or lower, and was dissolved therein. The solution was added dropwise into 800 kg of water at 30.degree. C. in 30 minutes. The resulting pigment was collected by filtration and washed with water to prepare an aqueous paste of oxytitanium phthalocyanine (hereinafter referred to as "Aqueous paste (3)"). The solid content of this aqueous paste was 22%.

A portion of this aqueous paste was dried and subjected to X-ray diffraction measurement. The X-ray pattern is shown in FIG. 8.

n-hexane (20 kg) was added to 4.5 kg of Aqueous paste (3), and the mixture was subjected to milling treatment with glass beads of 1 mm in diameter at 20.degree. C. for 20 hours. The solid matter was separated from this liquid dispersion, and was washed sufficiently with n-hexane and dried to give I-type crystalline oxytitanium phthalocyanine in a yield of 0.9 kg.

EXAMPLES 33-39

The treatment was conducted in the same manner as in Example 32 except that the treatment solvent, the treatment time, and the treatment temperature were changed. The results are shown in Table 5.

TABLE 5__________________________________________________________________________Example Starting oxytitanium Treatment Treatment Treatment ResultingNo. phthalocyanine solvent temperature (.degree.C.) time (hours) crystal form__________________________________________________________________________32 Aqueous paste (3) n-Hexane 20 20 Type I33 Aqueous paste (3) n-Octane 20 20 Type I34 Aqueous paste (3) n-Decane 20 20 Type I35 Aqueous paste (3) n-Octane 50 15 Type I36 Aqueous paste (3) n-Dodecane 50 15 Type I37 Aqueous paste (3) n-Dodecane 70 10 Type I38 Aqueous paste (3) 2-Methylpentane 50 15 Type I39 Aqueous paste (3) 2-Methyloctane 50 20 Type I__________________________________________________________________________

REFERENCE EXAMPLES 11-25

The same treatment as in Example 14 was conducted except that Aqueous paste (1) and the treatment time and the treatment time are changed as shown in Table 6. The results are shown in Table 6.

The B-type and A-type crystalline oxytitanium phthalocyanines were prepared respectively according to preparation examples disclosed in JP-A Sho-61-239248 (U.S. Pat. No. 4,728,592), or JP-A Sho-62-67094 (U.S. Pat. No. 4,664,997).

TABLE 6__________________________________________________________________________Reference Starting oxytitanium Treatment Treatment Treatment ResultingExample No. phthalocyanine solvent temperature (.degree.C.) time (hours) crystal form__________________________________________________________________________12 Type B n-Hexane 20 20 Type B13 Type B n-Octane 20 20 Type B14 Type B n-Dodecane 50 15 Type B15 Type A n-Hexane 20 20 Type A16 Type A n-Octane 20 20 Type A17 Type A n-Dodecane 50 15 Type A18 Dried matter of n-Hexane 20 20 Type B aqueous paste (1)19 Dried matter of n-Hexane 20 20 Type B aqueous paste (2)20 Dried matter of n-Hexane 20 20 Type B aqueous paste (3)21 Dried matter of n-Octane 20 20 Type B aqueous paste (1)22 Dried matter of n-Octane 40 20 Type B aqueous paste (1)23 Dried matter of n-Decane 60 15 Type B aqueous paste (1)24 Dried matter of n-Dodecane 60 15 Type B aqueous paste (1)25 Dried matter of 2-Methyloctane 20 30 Type B aqueous paste (1)__________________________________________________________________________

Claims

1. A process for producing a crystalline I-type oxytitanium phthalocyanine having strong peaks in Cuk.alpha. characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 9.0.degree., 14.2.degree., 23.9.degree. and 27.1.degree., comprising: milling-treatment one of (A) or (B) with a solvent selected from the group consisting of n-pentane, n-hexane, n-octane, n-decane, n-dodecane, 2-methylpentane, 2-methyloctane, ligroin, petroleum benzin and mixtures thereof wherein;

(A) is at least one oxytitanium phthalocyanine selected from the group consisting of a first oxytitanium phthalocyanine having strong peaks in CuK.alpha. characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 7.2.degree., 14.2.degree., 24.0.degree. and 27.2.degree. and a second oxytitanium phthalocyanine having strong peaks in CuK.alpha. characteristics X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 7.1.degree., 10.4.degree. and 27.3.degree.; and

(B) is an aqueous paste of a third oxytitanium phthalocyanine.

2. The process of claim 1, wherein the oxytitanium phthalocyanine to be treated has strong CuK.alpha. peaks in characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 7.1.degree., 10.4.degree., and 27.3.degree. and the aqueous paste is not employed.

3. The process of claim 1, wherein the the oxytitanium phthalocyanine to be treated is a mixture of a first oxytitanium phthalocyanine having strong CuK.alpha. peaks in characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 7.2.degree., 14.2.degree., 24.0.degree., and 27.2.degree., and a second oxytitanium phthalocyanine having strong peaks in CuK.alpha. characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 7.1.degree., 10.4.degree., and 27.3.degree. and the aqueous paste is not employed.

4. The process of claim 1, wherein the aqueous paste to be treated is derived according to an acid-pasting method.

5. The process of claim 1, wherein the weight ratio of the oxytitanium phthalocyanine to the solvent is in the range of from 1:5 to 1:40.

6. The process of claim 1, wherein the milling treatment is conducted at a temperature not higher than 80.degree. C.

7. The process of claim 1, wherein the oxytitanium phthalocyanine to be treated has strong peaks in CuK.alpha. characteristic X-ray diffraction at Bragg angles (2.theta..+-.0.2.degree.) of 7.2.degree., 14.2.degree., 24.0.degree., and 27.2.degree. and the aqueous paste is not employed.