JP7755611B2 - Method for producing halogenated metal-free phthalocyanine - Google Patents

Description

The present invention relates to a method for producing a halogenated metal-free phthalocyanine.

A wide variety of dyes, pigments, and other colorants are used in a variety of applications, including information display devices such as liquid crystal color displays and information recording materials such as inkjet inks, as well as in resin colorants, fiber colorants, paper colorants, writing instrument colorants, paints, coatings, and various printing inks. Colorants must not only be suitable for the object being colored, but also exhibit properties such as color tone, tinting strength, clarity, transparency, hiding power, weather resistance, solvent resistance, chemical resistance, fluidity, and dispersibility, depending on the application. Pigments, in particular, are often used in applications requiring a variety of resistances.

Commonly used phthalocyanine pigments often contain metals. In some applications, there is a movement to refrain from using compounds that contain specific elements in their structure. For example, regulated values for copper (Cu) are set in the Water Supply Act, Water Pollution Control Act, and Basic Environment Act, and there are concerns that industry groups and other organizations may regulate them in the future.

When using conventional pigments as is, possible solutions include reducing the amount of pigment used or mixing multiple pigments. In the case of phthalocyanine pigments, alternative solutions include changing the central metal. In recent years, there has been a demand for technology to reduce the metal content in pigments. For example, a method has been proposed in which crude halogenated copper phthalocyanine is treated with fuming sulfuric acid to produce a halogenated copper phthalocyanine pigment in which the free copper content is reduced to a certain level or below (Patent Document 1).

Patent No. 4584547

However, until now, no method has been known to easily remove the metal from the structure of halogenated metal phthalocyanine to produce a substantially metal-free halogenated phthalocyanine (halogenated metal-free phthalocyanine) that exhibits blue or green hues.

The present invention was made in consideration of the problems associated with the prior art, and its objective is to provide a simple method for producing halogenated metal-free phthalocyanines that exhibit vivid blue and green color tones. It is also an objective of the present invention to provide halogenated metal-free phthalocyanines produced by this production method, as well as colorants and bioplastics that use this halogenated metal-free phthalocyanines.

That is, according to the present invention, there is provided the following method for producing a halogenated metal-free phthalocyanine.
[1] A method for producing a halogenated metal-free phthalocyanine, comprising the steps of mixing a halogenated manganese phthalocyanine with an acid component and eliminating manganese from the halogenated manganese phthalocyanine to obtain a halogenated metal-free phthalocyanine, wherein the acid component is oleum or 90% by mass or more concentrated sulfuric acid when the halogenated manganese phthalocyanine has an average number of halogen groups per molecule that is more than 0 and not more than 4, and the acid component is oleum when the halogenated manganese phthalocyanine has an average number of halogen groups per molecule that is more than 4.
[2] The method for producing a halogenated metal-free phthalocyanine according to [1], wherein the halogenated manganese phthalocyanine and the acid component are mixed at a temperature of 5°C or less.
[3] The method for producing a halogenated metal-free phthalocyanine according to the above [1] or [2], further comprising a step of obtaining the halogenated manganese phthalocyanine by the Wyler process.
[4] The method for producing a halogenated metal-free phthalocyanine according to any one of [1] to [3], wherein the halogen atom in the halogenated manganese phthalocyanine is at least one of a chlorine atom and a bromine atom.

The present invention also provides the following halogenated metal-free phthalocyanine, colorant, and bioplastic.
[5] A halogenated metal-free phthalocyanine obtained by the production method according to any one of [1] to [4] above.
[6] A colorant containing the halogenated metal-free phthalocyanine according to [5] above.
[7] A bioplastic containing a bioplastic material and the colorant described in [6].

The present invention provides a simple method for producing halogenated metal-free phthalocyanines that exhibit vivid blue and green hues. The present invention also provides halogenated metal-free phthalocyanines produced by this production method, as well as colorants and bioplastics that use these halogenated metal-free phthalocyanines.

<Halogenated Metal-Free Phthalocyanine and Its Method of Production>
Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments. One embodiment of the method for producing a halogenated metal-free phthalocyanine of the present invention includes a step of mixing a halogenated manganese phthalocyanine with an acid component and removing manganese from the halogenated manganese phthalocyanine to obtain a halogenated metal-free phthalocyanine (a demetallization step). When the average number of halogen groups substituted per molecule of the halogenated manganese phthalocyanine is greater than 0 and not greater than 4, the acid component is oleum or 90% by mass or more concentrated sulfuric acid. When the average number of halogen groups substituted per molecule of the halogenated manganese phthalocyanine is greater than 4, the acid component is oleum. One embodiment of the halogenated metal-free phthalocyanine of the present invention is obtained by the above-mentioned production method.

(definition)
Halogenated phthalocyanines having an average number of halogen groups substituted per molecule of more than 0 to 16 or less are also referred to as "polyhalogenophthalocyanines." Similarly, halogenated manganese phthalocyanines and halogenated metal-free phthalocyanines having an average number of halogen groups substituted per molecule of more than 0 to 16 or less are also referred to as "polyhalogenomanganese phthalocyanines" and "polyhalogenometal-free phthalocyanines," respectively. The numbers in parentheses before "halogeno,""bromo," and "chloro" indicate the average number of "halogen groups,""bromine (Br) groups," and "chlorine (Cl) groups" substituted per molecule, respectively. Meanwhile, the numbers preceded by a hyphen before "halogeno,""bromo," and "chloro" indicate the substitution positions, respectively. In addition, "metal-free" in this specification means that when the target substance is analyzed by inductively coupled plasma (ICP) atomic emission spectrometry, it is not substantially detected that the target substance contains metals such as manganese.

(Demetallization process)
In the metal removal step, the halogenated manganese phthalocyanine (poly(1-16)halogenomanganese phthalocyanine) is mixed with an acid component, thereby removing manganese (Mn) from the halogenated manganese phthalocyanine, thereby obtaining a halogenated metal-free phthalocyanine (poly(1-16)halogenometal-free phthalocyanine).

The type and concentration of the acid component required for demetallization varies depending on the average substitution number of halogen groups in the halogenated manganese phthalocyanine. Therefore, the type of acid component used must be appropriately selected depending on the average substitution number of halogen groups in the halogenated manganese phthalocyanine. Specifically, when the average substitution number of halogen groups per molecule of the halogenated manganese phthalocyanine is greater than 0 and less than 4, oleum or 90% by mass or more concentrated sulfuric acid is used as the acid component. On the other hand, when the average substitution number of halogen groups per molecule of the halogenated manganese phthalocyanine is greater than 4, oleum is used as the acid component. In this way, by selecting and using an acid component depending on the average substitution number of halogen groups in the halogenated manganese phthalocyanine, manganese can be efficiently desorbed from the halogenated manganese phthalocyanine to obtain a halogenated metal-free phthalocyanine.

Concentrated sulfuric acid should be 90% by mass or more, preferably 93% by mass or more, and more preferably 95% by mass or more. There is no upper limit to the concentration of concentrated sulfuric acid, and 100% by mass concentrated sulfuric acid may be used.

The oleum used has a sulfur trioxide (SO ₃ ) concentration of preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 20% by mass or more. Hereinafter, oleum having a sulfur trioxide concentration of X% by mass will also be referred to as "X% by mass oleum" or "X% oleum."

In the demetallization process, the halogenated manganese phthalocyanine is mixed with an acid component, and the halogenated manganese phthalocyanine is dissolved in the acid component to obtain an acid solution. The halogen atom in the halogenated manganese phthalocyanine is preferably at least one of a chlorine atom (Cl) and a bromine atom (Br). The temperature of the acid solution is preferably 5°C or less, more preferably 3°C or less, and particularly preferably 0°C or less. By maintaining the temperature of the acid solution within the above range, the occurrence of side reactions can be suppressed and the yield of halogenated metal-free phthalocyanine can be improved. The time for mixing the halogenated manganese phthalocyanine with the acid component is not particularly limited and may be set appropriately within the range of, for example, 0.1 to 5 hours.

(Manufacturing process of halogenated manganese phthalocyanine)
The halogenated manganese phthalocyanine used as a raw material can be produced, for example, by the Wyler process (urea process). That is, the production method of this embodiment preferably further includes a step of obtaining a halogenated manganese phthalocyanine by the Wyler process. A halogenated manganese phthalocyanine can also be produced by the nitrile process, but this is disadvantageous in terms of cost compared to the Wyler process. Furthermore, a halogenated metal-free phthalocyanine can also be obtained by producing a metal-free phthalocyanine by the nitrile process and then halogenating it, but this is disadvantageous in terms of cost.

The Wyler process (urea process) is a method for producing halogenated manganese phthalocyanine by heating and stirring halogenated phthalic acids, urea, metal salts, and a catalyst, along with optional clarifying aids and stirring aids, at high temperatures in the presence or absence of a high-boiling organic solvent. Any of the reaction solvents conventionally used in the Wyler process can be used as the high-boiling organic solvent. Examples of catalysts that can be used include titanium tetrachloride, tetrabutyl orthotitanate, and tetrapropyl orthotitanate. For industrial use, products such as "Orgatix TA-10" manufactured by Matsumoto Pharmaceutical Industries Co., Ltd. can be used.

(Precipitation process)
It is preferable to dissolve the halogenated manganese phthalocyanine in an acid component and then, for example, remove the metal from the phthalocyanine to precipitate the resulting component (halogenated metal-free phthalocyanine). Examples of the method for precipitating the halogenated metal-free phthalocyanine include the following methods (1) to (3).
(1) A method in which a hydrous acid is added to an acid solution to reduce the acid concentration, thereby precipitating a halogenated metal-free phthalocyanine. (2) A method in which an acid solution is made to absorb water, thereby reducing the acid concentration, thereby precipitating a halogenated metal-free phthalocyanine. (3) A method in which an acid solution is poured into a large amount of water or ice water that is being vigorously stirred or jetted, thereby instantaneously precipitating a halogenated metal-free phthalocyanine.

The water or ice water used in method (3) above may contain an organic solvent. Among methods (1) to (3) above, method (3) is preferred. It is particularly preferred to use a vacuum suction device such as an aspirator or ejector to jet water at high speed, and to use the vacuum to draw in the acid solution, which is then brought into contact with the jetted water and diluted, thereby precipitating particulate halogenated metal-free phthalocyanine (pigment particles). It is also preferred to inject the acid solution dropwise into vigorously stirred water in a mixing vessel equipped with a high-speed mixer such as a dissolver or homomixer, or a high-efficiency agitator, and then diffuse the acid solution into the water to precipitate particulate halogenated metal-free phthalocyanine (pigment particles).

(Pigmentation treatment process)
The precipitated halogenated metal-free phthalocyanine is preferably subjected to a pigmentation treatment (pigmentation). Specifically, it is preferable to remove impurities to increase purity, refine the particles, and adjust the pigment crystals. More specifically, there is a method in which an acid solution is poured into water or ice water containing a hydrophobic organic solvent or a hydrophilic organic solvent to precipitate the halogenated metal-free phthalocyanine, while also refining the particles and adjusting the crystals. Another method involves adding a hydrophobic organic solvent or a hydrophilic organic solvent to treatment water containing the precipitate.

Following the precipitation process, it is preferable to carry out a known pigmentation process such as the solvent finish method, in which crystallization is promoted by heating the material in an organic solvent such as xylol or in a xylol emulsion. Furthermore, if necessary, at least one of surfactants, rosin, various resins, polymer dispersants, and pigment derivatives may be used in combination.

Pigments can be micronized during the precipitation process or in a process after the precipitation process. Examples of methods for micronizing pigments in a process after the precipitation process include known pigment micronization methods such as the so-called dry grinding method and salt milling method, in which the pigment is kneaded and milled in a mixer such as a kneader together with a water-soluble salt and, if necessary, a water-soluble organic solvent to micronize the pigment.

If the pigment particles are too fine, it is preferable to knead them with an organic solvent using a kneader or similar device and adjust them while allowing crystal growth. The average particle size of the pigment's primary particles is preferably 5 to 130 nm, and more preferably 10 to 110 nm.

The halogen groups that constitute the halogenated metal-free phthalocyanine are preferably at least one of chlorine (Cl) and bromine (Br) atoms. When the average number of halogen groups per molecule is low, the color tends to be blue. As the average number of halogen groups per molecule increases, the color tends to become greenish blue to green. Note that the greater the number of bromine (Br) groups, the more yellowish green the color tends to be.

Halogenated metal-free phthalocyanine can also be produced by halogenating a metal-free phthalocyanine pigment, but this is disadvantageous in terms of cost and makes it difficult to control the average number of halogen groups substituted. For this reason, the production method of this embodiment, in which manganese is removed from a halogenated manganese phthalocyanine to obtain a halogenated metal-free phthalocyanine, is preferred from the perspectives of cost and strict control over the structure of the resulting halogenated metal-free phthalocyanine.

From the perspective of more precisely controlling the type and average substitution number of halogen groups, it is preferable to use halogenated phthalic anhydrides, halogenated phthalimides, halogenated phthalodinitriles, or halogenated aminoiminoisoindolenines having the desired type and substitution number of halogen groups as raw materials, and subject the resulting halogenated manganese phthalocyanine to demetallation. Furthermore, brominated manganese phthalocyanines in which the only halogen groups are bromine (Br) atoms can be obtained by, for example, using tribromophthalic anhydride (or tetrabromophthalic anhydride), tribromophthalimide (or tetrabromophthalimide), tribromophthalodinitriles (or tetrabromophthalodinitriles), or tribromoaminoiminoisoindolenines (or tetrabromoaminoiminoisoindolenines) as raw materials and subjecting them to a condensation reaction in the presence of a metal salt.

The halogenated metal-free phthalocyanine produced by the production method of this embodiment, which is useful as a blue pigment, green pigment, etc., has excellent fastness, such as solvent resistance and heat resistance, as well as clarity. Specifically, the halogenated metal-free phthalocyanine of this embodiment is far superior in fastness to dyes, lake pigments, monoazo pigments, etc. The halogenated metal-free phthalocyanine of this embodiment exhibits clarity equal to or greater than that of copper phthalocyanine and zinc phthalocyanine, and is superior in clarity to phthalocyanines containing metals such as cobalt, nickel, and iron. For these reasons, the halogenated metal-free phthalocyanine of this embodiment is particularly useful, for example, as a colorant for coloring bioplastics or as a pigment for pixels in color filters.

By using the halogenated metal-free phthalocyanine of this embodiment, a blue or green pigment dispersion composition can be prepared. The pigment dispersion composition can be obtained, for example, by mixing and grinding the halogenated metal-free phthalocyanine with a metal soap or the like. Alternatively, the pigment dispersion composition can be obtained by kneading and dispersing the halogenated metal-free phthalocyanine together with a dispersant in a resin. Furthermore, a pigment dispersion composition can be obtained by mixing the halogenated metal-free phthalocyanine with various liquid media, polymerizable liquid media such as polymerizable oligomers and polymerizable monomers, plasticizers, oligomers, and resin media such as synthetic resins, and, if necessary, dispersing aids such as polymeric dispersants and low-molecular-weight dispersing aids.

<Coloring Agent>
One embodiment of the colorant of the present invention contains the above-mentioned halogenated metal-free phthalocyanine. The colorant of this embodiment can be obtained by mixing the above-mentioned pigment dispersion composition with components such as a dilution medium, a thermoplastic polymer, a reactive polymer, a reactive oligomer, a polymerizable monomer, and a crosslinking agent used as a coating material. Furthermore, a curing catalyst or a polymerization catalyst may be added as needed. Various colored articles can be produced by coloring articles using the colorant of this embodiment or the above-mentioned pigment dispersion composition. Furthermore, colored bioplastics can be produced by mixing a bioplastic material with the above-mentioned colorant.

The present invention will be explained in detail below based on examples, but the present invention is not limited to these examples. Note that "parts" and "%" in the examples and comparative examples are by weight unless otherwise specified.

<Production of halogenated metal-free phthalocyanine>
Example 1
[1] (16) Synthesis of Chloromanganese Phthalocyanine A reaction vessel equipped with a stirrer, a reflux condenser, and a thermometer and a heating device were prepared. 144.0 parts of nitrobenzene and 31.2 parts of manganese chloride tetrahydrate were placed in the reaction vessel and heated to 160°C with stirring for 8 hours to dehydrate. After cooling, 114.4 parts of tetrachlorophthalic anhydride and 120.1 parts of urea were added, and the temperature was gradually raised to 120°C. 22.7 parts of tetrabutyl orthotitanate were added, and the temperature was raised to 175°C, after which the reaction was continued with stirring for 4 hours. The temperature immediately before the end of the reaction was 190°C. After removing the reaction medium (nitrobenzene), the mixture was treated sequentially with dilute acid and dilute alkali to remove impurities, yielding 101.8 parts of a yellowish-brown crude pigment (A1). The yield was 91.0%.

Structural analysis was performed using infrared spectroscopy (IR), X-ray fluorescence spectroscopy (XRF), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS), confirming that the resulting crude pigment (A1) was (16) chloromanganese phthalocyanine. The metal (manganese) content and halogen content of the sample were measured using inductively coupled plasma (ICP) atomic emission spectroscopy after decomposing the sample with strong acid using a microwave decomposition device. The other examples below were also analyzed using the same method.

[2] Demetallization of (16) chloromanganese phthalocyanine A reaction vessel equipped with a stirrer, an air-cooled tube, and a thermometer, and a cooling device were prepared. 200 parts of 20% fuming sulfuric acid were placed in the reaction vessel, and 10 parts of crude pigment (A1) were slowly added to the reaction vessel while stirring under ice cooling, without generating heat, and the mixture was stirred at 0°C for 1 hour. The reaction product was added dropwise to 2,000 parts of stirred ice water, and the resulting precipitate was filtered and washed with water. The mixture was then pigmented by a xylene-emulsion method, yielding 7.7 parts of a vivid green (16) chlorometal-free phthalocyanine (A2).

Example 2
[1] Synthesis of bromo(12)chloromanganese phthalocyanine [0049] Except for using 22.7 parts of 4-bromophthalic anhydride and 85.8 parts of tetrachlorophthalic anhydride instead of tetrachlorophthalic anhydride, 92.3 parts of a greenish-black crude pigment (B1) was obtained in a yield of 87.1% in the same manner as in Example 1[1].

[2] Demetallization of Bromo(12)chloromanganese Phthalocyanine [0123] Except for using the crude pigment (B1) instead of the crude pigment (A1), the same procedure as in Example 1[2] was carried out to obtain 8.7 parts of a vivid green bromo(12)chlorometal-free phthalocyanine (B2).

Example 3
[1] Synthesis of (2) bromo(8)chloromanganese phthalocyanine [0049] 77.6 parts of a greenish-black crude pigment (C1) was obtained in a yield of 77.5% in the same manner as in Example 1[1], except that 45.4 parts of 4-bromophthalic anhydride and 57.2 parts of tetrachlorophthalic anhydride were used instead of tetrachlorophthalic anhydride.

[2] Demetallization of (2) bromo(8) chloromanganese phthalocyanine [0123] Except for using crude pigment (C1) instead of crude pigment (A1), 9.1 parts of vivid bluish-green (2) bromo(8) chloro metal-free phthalocyanine (C2) was obtained in the same manner as in the above-mentioned Example 1 [2].

Example 4
[1] Synthesis of (4) Bromo(12)chloromanganese phthalocyanine [0049] Except for using 46.4 parts of tetrabromophthalic anhydride and 85.8 parts of tetrachlorophthalic anhydride instead of tetrachlorophthalic anhydride, the same procedure as in Example 1[1] was repeated to obtain 116.0 parts of a greenish-black crude pigment (D1). The yield was 89.5%.

[2] Demetallization of (4) bromo(12) chloromanganese phthalocyanine 7.3 parts of a vivid yellowish-green (4) bromo(12) chloro metal-free phthalocyanine (D2) was obtained in the same manner as in Example 1 [2] above, except that crude pigment (D1) was used instead of crude pigment (A1). Crude pigment (D1) contained a small amount of (16) bromomanganese phthalocyanine. However, the (4) bromo(12) chloro metal-free phthalocyanine (D2) obtained by demetallization did not contain (16) bromo metal-free phthalocyanine. It is presumed that decomposition occurred during demetallization due to sterically restricted halogen configuration.

Example 5
[1] Synthesis of (12.8) chloromanganese phthalocyanine [0049] Except for using 103.0 parts of (3.2) chlorophthalic anhydride instead of tetrachlorophthalic anhydride, the same procedure as in Example 1 [1] was repeated to obtain 93.2 parts of a grayish-brown crude pigment (E1). The crude pigment yield was 92.4%.

[2] Demetallization of (12.8) chloromanganese phthalocyanine [0123] Except for using the crude pigment (E1) instead of the crude pigment (A1), 8.6 parts of a vivid bluish green (12.8) chloro metal-free phthalocyanine (E2) was obtained in the same manner as in the above-mentioned Example 1 [2].

Example 6
[1] (4) Synthesis of chloromanganese phthalocyanine pigment [0063] In the same manner as in Example 1 [1] above, except for using 73.0 parts of 4-chlorophthalic anhydride instead of tetrachlorophthalic anhydride, 60.4 parts of a greenish-black crude pigment (F1) was obtained in a yield of 85.6%.

[2] (4) Demetallization of Chloromanganese Phthalocyanine 7.9 parts of a vivid greenish blue (4) chlorometal-free phthalocyanine (F2) was obtained in the same manner as in Example 1 [2] above, except that the crude pigment (F1) was used instead of the crude pigment (A1) and 200 parts of 95% sulfuric acid was used instead of the 20% oleum.

Example 7
[1] Synthesis of chloromanganese phthalocyanine [0049] 48.2 parts of a greenish-black crude pigment (G1) was obtained in a yield of 80.1% in the same manner as in Example 1[1], except that 18.3 parts of 4-chlorophthalic anhydride and 44.4 parts of phthalic anhydride were used instead of tetrachlorophthalic anhydride.

[2] Demetallization of chloromanganese phthalocyanine 7.6 parts of a vivid blue chlorometal-free phthalocyanine (G2) was obtained in the same manner as in Example 1 [2] above, except that the crude pigment (G1) was used instead of the crude pigment (A1) and 200 parts of 95% sulfuric acid was used instead of the 20% oleum.

(Reference example 1)
[1] Synthesis of unsubstituted manganese phthalocyanine [0047] 47.7 parts of a dull green crude pigment (H1) was obtained in a yield of 84.0% in the same manner as in Example 1[1], except that 59.2 parts of phthalic anhydride was used instead of tetrachlorophthalic anhydride and 0.1 parts of ammonium molybdate was used instead of tetrabutyl orthotitanate.

[2] Demetallization of unsubstituted manganese phthalocyanine 500 parts of 5% sulfuric acid and 10 parts of crude pigment (H1) were placed in a stirring tank. The mixture was heated to 80°C and stirred for 1 hour, then filtered and washed with water. Next, the mixture was converted into a pigment by a butyl cellosolve emulsion method, yielding 9.3 parts of a vivid blue metal-free phthalocyanine (H2).

(Comparative Example 1)
An attempt was made to remove metal in the same manner as in Reference Example 1 [2] above, except that crude pigment (A1) was used instead of crude pigment (H1), but the resulting crude pigment remained yellowish-brown in color.

(Comparative Example 2)
An attempt was made to demetallize the crude pigment (A1) in the same manner as in Example 1 [2] above, except that 200 parts of 96% sulfuric acid was used instead of the 20% oleum. Analysis revealed that the manganese concentration in the resulting product was the same as that in the crude pigment (A1), and demetalization was not possible.

(Comparative Example 3)
An attempt was made to demetallize crude pigment (A1) in the same manner as in Example 1 [2] above, except that 200 parts of 98% sulfuric acid was used instead of 20% oleum. Analysis revealed that the manganese concentration in the resulting product was about 50% of the manganese concentration in crude pigment (A1), and complete demetallization was not possible.

(Comparative Example 4)
An attempt was made to demetallize a crude pigment (A1) in the same manner as in Example 1 [2] above, except that 200 parts of 100% sulfuric acid was used instead of 20% oleum. Analysis revealed that the manganese concentration in the resulting product was about 40% of the manganese concentration in the crude pigment (A1), and complete demetallization was not possible.

(Comparative Example 5)
An attempt was made to demetallize the crude pigment (F1) in the same manner as in Example 6[2] above, except that 200 parts of 85% sulfuric acid was used instead of 95% sulfuric acid. Analysis revealed that the manganese concentration in the resulting product was the same as that in the crude pigment (F1), and demetalization was not possible.

(Comparative Example 6)
An attempt was made to demetallize the crude pigment (G1) in the same manner as in Example 7[2] above, except that 200 parts of 85% sulfuric acid was used instead of 95% sulfuric acid. Analysis revealed that the manganese concentration in the obtained product was about 70% of the manganese concentration in the crude pigment (G1), and complete demetallization was not possible.

The manufacturing method of the present invention is useful, for example, as a method for easily producing halogenated metal-free phthalocyanines suitable as colorants for coloring bioplastics and as pigments for pixels in color filters.

Claims (4)

a step of mixing a halogenated manganese phthalocyanine with an acid component and eliminating manganese from the halogenated manganese phthalocyanine to obtain a halogenated metal-free phthalocyanine,
when the average number of halogen groups substituted per molecule of the halogenated manganese phthalocyanine is more than 0 and not more than 4, the acid component is oleum or 90% by mass or more concentrated sulfuric acid;
When the average number of halogen groups substituted per molecule of the halogenated manganese phthalocyanine is more than 4, the acid component is fuming sulfuric acid. The method for producing a halogenated metal-free phthalocyanine according to claim 1, wherein the halogenated manganese phthalocyanine and the acid component are mixed at a temperature of 5°C or less. The method for producing a halogenated metal-free phthalocyanine according to claim 1, further comprising the step of obtaining the halogenated manganese phthalocyanine by the Wyler process. The method for producing a halogenated metal-free phthalocyanine according to any one of claims 1 to 3, wherein the halogen atoms in the halogenated manganese phthalocyanine are at least one of chlorine atoms and bromine atoms.