Heterocyclic organic pigment and its preparation method and application

Abstract

In the preparation method of heterocyclic organic pigments provided in the present application, with the coordinated cooperation of each step, a heterocyclic organic pigment with a wide chromatographic range, bright color, high tinting power and good dispersibility can be prepared, and at the same time, the heterocyclic organic pigment has high transparency and hue adjustability, and has excellent hiding performance. Furthermore, the present application uses dilute phosphoric acid as a precipitate, so that the filtered phosphoric acid solution can be used to prepare by-product phosphates, which can reduce pollution and save production costs; the alcohol solvent in the pigmentation process is easy to recover and can be reused; at the same time, with the dissolution in polyphosphoric acid and post-treatment in an alkaline medium, under the overall coordination of each step, the preparation method has low process energy consumption, easy waste liquid treatment, and good environmental and economic value.

Description

Technical Field

[0001] The present application relates to the field of pigment preparation, and in particular to a heterocyclic organic pigment and a preparation method and application thereof. Background Art

[0002] Heterocyclic organic pigments have excellent application properties such as bright color and high tinting strength, and are widely used in coatings, inks, plastics, rubber, fabric printing, cosmetics and other fields. Among them, dioxazine pigment (PV23) is an extremely important high-performance organic pigment with bright colors, high tinting strength and excellent fastness. It is widely used in the coloring of high-quality inks, coatings, paints, plastics and other fields.

[0003] At present, dioxazine pigment (PV23) is mainly prepared by a two-step method. The first step is to synthesize the crude dioxazine pigment; the second step is to further pigmentize the crude product to prepare a high-performance purple pigment with commercial use. The traditional pigmentization processes mainly include ball milling, kneading and acid dissolution. The ball milling method mainly uses the crude product to ball mill with inorganic salts and trace solvents, and then solvent treatment and acid treatment to remove the metal impurities generated during ball milling; the kneading method mainly uses the crude product to knead with inorganic salts and solvents, and then removes salt, solvent and impurities; but both the ball milling method and the kneading method require the use of large-power equipment, which has high energy consumption, high maintenance costs, high noise, and a bad working environment; at the same time, during the ball milling or kneading process, the abrasive and the equipment collide with high intensity, generating secondary impurities, and a large amount of abrasive and equipment inner wall powder enter the pigment, requiring subsequent acid treatment. The traditional acid dissolution method mainly uses concentrated sulfuric acid to dissolve the crude product, and then precipitates it in water for further post-processing; but this method produces a large amount of waste acid, and the product quality is also low, and there is no industrial value. At the same time, in the current preparation method of dioxazine pigments, it is very difficult to adjust the hue, transparency, etc., which brings a lot of inconvenience to the application of industrial downstream products. Summary of the invention

[0004] Based on this, the present application provides a heterocyclic organic pigment and its preparation method and application. The preparation method provided by the present application has low process energy consumption, easy waste liquid treatment, and good environmental and economic value. At the same time, the pigment prepared by the preparation method of the present application has the advantages of transparency and high hiding power, and has good transparency and hue adjustability.

[0005] In a first aspect of the present application, a method for preparing a heterocyclic organic pigment is provided, comprising the following steps:

[0006] Dissolving a crude heterocyclic organic pigment in polyphosphoric acid to prepare a crude solution;

[0007] The crude product solution is mixed with dilute phosphoric acid to precipitate solids, which are filtered and the filter cake is collected;

[0008] The filter cake is subjected to pressurization or reflux treatment in an alcohol solvent to prepare a pigment product;

[0009] The pigmented product is placed in an alkaline medium to remove impurities to prepare the heterocyclic organic pigment.

[0010] In one embodiment, the crude heterocyclic organic pigment comprises the following components in parts by weight:

[0011] 90 to 100 parts of crude dioxazine pigment,

[0012] 0 to 10 parts of crude color pigment;

[0013] The crude tinting pigment comprises a crude quinacridone pigment or a crude anthraquinone pigment.

[0014] In one embodiment, the mass ratio of the crude heterocyclic organic pigment to the polyphosphoric acid is 1:4.5-7;

[0015] Calculated by phosphoric acid content, the mass fraction of the polyphosphoric acid in the aqueous solution is 110% to 118%.

[0016] In one embodiment, the process parameters for dissolving the crude heterocyclic organic pigment in polyphosphoric acid include: a dissolution temperature of 100° C. to 130° C.

[0017] In one of the embodiments, the mass fraction of the dilute phosphoric acid is 5% to 30%, and the mass ratio of the crude heterocyclic organic pigment to the dilute phosphoric acid is 1:6 to 10.

[0018] In one embodiment, the crude product solution is mixed with dilute phosphoric acid, and the process parameters for precipitating solids include: a precipitation temperature of 0°C to 110°C.

[0019] In one embodiment, the process parameters for pressurizing or refluxing the filter cake in an alcohol solvent include one or more of the following technical features:

[0020] (1) The mass ratio of the filter cake to the alcohol solvent is 1:8-20;

[0021] (2) refluxing the filter cake in an alcohol solvent having 1 to 2 carbon atoms for 6 to 15 hours;

[0022] (3) The filter cake is subjected to a pressure treatment in an alcohol solvent having 3 to 4 carbon atoms at a pressure temperature of 120° C. to 140° C.

[0023] In one embodiment, the pH of the alkaline medium is 9-11.

[0024] In a second aspect of the present application, a heterocyclic organic pigment is provided, which is prepared by the preparation method of the heterocyclic organic pigment described in the first aspect.

[0025] The third aspect of the present application provides an application of the heterocyclic organic pigment described in the second aspect of the present application in the fields of coatings, inks, plastics, rubber, fabric printing and cosmetics.

[0026] In the preparation method of heterocyclic organic pigments provided in the present application, with the coordinated cooperation of each step, a heterocyclic organic pigment with a wide chromatographic range, bright color, high tinting power and good dispersibility can be prepared, and at the same time, the heterocyclic organic pigment has high transparency and hue adjustability, and has excellent hiding performance. Furthermore, the present application uses dilute phosphoric acid as a precipitate, so that the filtered phosphoric acid solution can be used to prepare by-product phosphates, which can reduce pollution and save production costs; the alcohol solvent in the pigmentation process is easy to recover and can be reused; at the same time, with the dissolution in polyphosphoric acid and post-treatment in an alkaline medium, under the overall coordination of each step, the preparation method has low process energy consumption, easy waste liquid treatment, and good environmental and economic value. DETAILED DESCRIPTION

[0027] The following is a further complete and clear description of the heterocyclic organic pigment, the preparation method of the heterocyclic organic pigment and the application of the heterocyclic organic pigment of the present application in conjunction with specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly understood.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0029] As used herein, "one or more" refers to any one, any two, or any two or more of the listed items.

[0030] In this application, "first aspect", "second aspect", "third aspect", "fourth aspect", "fifth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", "fifth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0031] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0032] In this application, when it comes to numerical ranges, unless otherwise specified, the above numerical ranges are deemed to be continuous and include the minimum and maximum values ​​of the range, as well as each value between such minimum and maximum values. Further, when a range refers to an integer, each integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges included therein.

[0033] The percentage contents involved in this application, unless otherwise specified, refer to mass percentage for solid-liquid mixing and solid-solid mixing, and refer to volume percentage for liquid-liquid mixing.

[0034] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0035] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows the temperature to fluctuate within the accuracy range of instrument control.

[0036] In the present application, "alcohol solvent having 1 to 2 carbon atoms" refers to an alcohol containing 1 to 2 carbon atoms. Each time it appears, it can be independently a C1 alcohol solvent or a C2 alcohol solvent. Suitable examples include, but are not limited to, methanol (CH3OH), ethanol (CH3CH2OH) or ethylene glycol (CH3OHCH3OH).

[0037] In the present application, "alcohol solvent having 3 to 4 carbon atoms" refers to an alcohol comprising 3 to 4 carbon atoms. Each time it appears, it can be independently a C3 alcohol solvent or a C4 alcohol solvent. Suitable examples include, but are not limited to, n-propanol (CH3CH2CH2OH), 1,2-propylene glycol (CH2OHCHOHCH3), 1,3-propylene glycol (CH2OHCH2CH2OH), glycerol (CH2OH-CH-OH-CH2OH), n-butanol (CH3CH2CH2CH2OH), 1,2-butanediol (CH3CH2CHOHCH2OH), 1,3-butanediol (CH3CHOHCH2CH2OH), 1,4-butanediol (CH2OHCH2CH2CH2OH), 1,2,4-butanetriol (CH2OHCHOHCH2CH2OH) or 1,2,3,4-butanetetrol (CH2OHCHOH CHOH CH2OH).

[0038] In the present application, unless otherwise specified, "dilute phosphoric acid" refers to a solution in which the mass fraction of H3PO4 is 3% to 50% and the solvent is water.

[0039] In a first aspect of the present application, a method for preparing a heterocyclic organic pigment is provided, comprising the following steps:

[0040] Dissolving a crude heterocyclic organic pigment in polyphosphoric acid to prepare a crude solution;

[0041] The crude product solution is mixed with dilute phosphoric acid to precipitate solids, which are filtered and the filter cake is collected;

[0042] The filter cake is subjected to pressurization or reflux treatment in an alcohol solvent to prepare a pigment product;

[0043] The pigmented product is placed in an alkaline medium to remove impurities to prepare the heterocyclic organic pigment.

[0044] In one example, the crude heterocyclic organic pigment comprises the following components in parts by weight:

[0045] 90 to 100 parts of crude dioxazine pigment,

[0046] 0 to 10 parts of crude color pigment;

[0047] The crude tinting pigment comprises a crude quinacridone pigment or a crude anthraquinone pigment.

[0048] Specifically, the weight proportions of the crude dioxazine pigment include, but are not limited to, 90 parts, 94 parts, 95 parts, 96 parts, 97 parts, 98 parts, 99 parts or 100 parts.

[0049] Specifically, the weight proportions of the crude color pigment include but are not limited to: 0 parts, 0.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 7 parts, 9 parts or 10 parts.

[0050] In one specific example, the crude quinacridone pigment is selected from single crystal or mixed crystal Pigment Red 122 (PR122), and the crude anthraquinone pigment is selected from Pigment Blue 60 (PB60).

[0051] The addition of the crude quinacridone pigment can adjust the hue of the heterocyclic organic pigment. The larger the weight of the crude quinacridone pigment, the heavier the red phase of the finished heterocyclic organic pigment. Specifically, the weight of the crude quinacridone pigment includes but is not limited to: 0, 0.5, 3, 3.5, 4, 4.5, 5, 7, 9 or 10 parts. Similarly, the larger the weight of the crude anthraquinone pigment, the heavier the blue phase of the finished heterocyclic organic pigment. Specifically, the weight of the crude anthraquinone pigment includes but is not limited to: 0, 0.5, 3, 3.5, 4, 4.5, 5, 7, 9 or 10 parts.

[0052] In the present application, the same preparation method can be used to process the crude dioxazine pigment and the crude dioxazine pigment-crude coloring pigment, so that the prepared pigment has higher color adjustability.

[0053] In one example, the mass ratio of the crude heterocyclic organic pigment to the polyphosphoric acid is 1:4.5-7. It is understandable that the mass ratio of the crude heterocyclic organic pigment to the polyphosphoric acid can be selected from any value between 1:4.5 and 7. Specifically, the mass ratio of the crude heterocyclic organic pigment to the polyphosphoric acid includes but is not limited to 1:4.5, 1:4.9, 1:5, 1:5.1, 1:5.2, 1:5.5, 1:6, 1:6.5 or 1:7. In the present application, by adjusting the mass ratio of the crude heterocyclic organic pigment to the polyphosphoric acid, it is beneficial to increase the dissolution rate of the crude pigment, dissolve it completely, and facilitate precipitation in dilute phosphoric acid.

[0054] In one example, the mass fraction of the polyphosphoric acid in the aqueous solution is 110% to 118% in terms of phosphoric acid content.

[0055] Polyphosphoric acid is a polymer of phosphoric acid. Phosphoric acid with a mass percentage of more than 100% is called polyphosphoric acid, which is a transparent viscous liquid. As the phosphoric acid content increases, the viscosity of the polyphosphoric acid increases.

[0056] In one example, the process parameters for dissolving the crude heterocyclic organic pigment in polyphosphoric acid include: a dissolution temperature of 100° C. to 130° C. Specifically, the dissolution temperature for dissolving the crude pigment in polyphosphoric acid includes but is not limited to 100° C., 110° C., 114° C., 115° C., 116° C., 118° C., 120° C., 125° C., or 130° C.

[0057] In one example, the process parameters for dissolving the crude pigment in polyphosphoric acid include: a dissolution time of 2 hours to 5 hours.

[0058] In one example, the mass fraction of the dilute phosphoric acid is 5% to 30%.

[0059] In one example, the mass ratio of the crude heterocyclic organic pigment to the dilute phosphoric acid is 1:6 to 10. By limiting the mass fraction of dilute phosphoric acid and the mass ratio of the crude pigment to dilute phosphoric acid, the amount of dilute phosphoric acid added can be controlled while ensuring the precipitation of the reaction liquid, thereby facilitating shortening the filtration time.

[0060] In one example, the crude solution is mixed with dilute phosphoric acid, and the process parameters for precipitating solids include: a precipitation temperature of 0°C to 110°C.

[0061] In one example, in the step of mixing the crude product solution with dilute phosphoric acid, precipitating solids, and collecting the filter cake after filtering, the solid content of the filter cake is 25% to 45%. At the same time, the mass fraction of phosphoric acid in the filtrate collected after the filtration process is 40% to 60%. In this step, the filtrate within this concentration range is suitable for direct use in the preparation of various phosphates, and the by-product phosphates include but are not limited to lithium iron phosphate, potassium dihydrogen phosphate, calcium hydrogen phosphate, sodium dihydrogen phosphate, and disodium hydrogen phosphate.

[0062] In one example, the process parameters for pressurizing or refluxing the filter cake in an alcohol solvent include: a mass ratio of the filter cake to the alcohol solvent is 1:8-20.

[0063] In one example, the process parameters for adding the filter cake to an alcohol solvent for pressurization or reflux treatment include: refluxing the filter cake in an alcohol solvent having 1 to 2 carbon atoms for 6 hours to 15 hours. The present application can prepare a transparent heterocyclic organic pigment by refluxing the filter cake in an alcohol solvent having 1 to 2 carbon atoms.

[0064] In one example, the process parameters for adding the filter cake to an alcohol solvent for pressurization or reflux treatment include: pressurizing the filter cake in an alcohol solvent having 3 to 4 carbon atoms at a pressurization temperature of 120° C. to 140° C. The present application can prepare a covering heterocyclic organic pigment by pressurizing the filter cake in an alcohol solvent having 3 to 4 carbon atoms.

[0065] In the present application, the treatment of the filter cake in the alcohol solvent can be selected from any one of pressurization or reflux treatment, which is convenient for flexibly adjusting the properties of the heterocyclic organic pigment from the perspective of practical application and increasing the adjustability of the heterocyclic organic pigment.

[0066] In one example, the step of removing impurities from the pigmented product in an alkaline medium comprises:

[0067] At 30°C to 70°C, an alkaline substance is added to the pigment product to adjust the pH to 9 to 11, and after part of the alcohol solvent contained in the pigment product is distilled off, water is added, filtered, and the filter cake is washed, dried, and crushed to prepare the heterocyclic organic pigment. Through the distillation process, the alcohol solvent used in the preparation process is easy to recover and can be reused repeatedly.

[0068] In one example, the pH of the alkaline medium is 9-11.

[0069] In one example, the alkaline substance used to adjust the pH includes, but is not limited to, sodium hydroxide, potassium hydroxide, or calcium hydroxide.

[0070] In one specific example, the method for preparing the transparent heterocyclic organic pigment comprises the following steps:

[0071] S1. Dissolving the crude pigment in polyphosphoric acid at 100°C to 130°C for 2-5h, wherein the weight ratio of the crude pigment to the polyphosphoric acid is 1:4.5 to 7, and the mass percentage of the polyphosphoric acid, calculated as H3PO4, is 110% to 118%; preparing a reaction solution;

[0072] S2. The reaction solution prepared in step S1 is precipitated in 5% to 30% by mass of dilute phosphoric acid at a precipitation temperature of 0°C to 110°C. The mass ratio of the crude pigment in the reaction solution to the dilute phosphoric acid is 1:6 to 10. After precipitation, a filtrate and a filter cake are prepared by filtration. The solid content of the filter cake is 25% to 45%, and the mass ratio of the dilute phosphoric acid in the filtrate is 40% to 60%. The filtrate in step S2 can be directly used for the preparation of various phosphates.

[0073] S3. The filter cake prepared in step S2 is refluxed in a methanol or ethanol solution for a reflux time of 6 h to 15 h to prepare a pigmented product;

[0074] S4. At 30°C to 70°C, add an alkaline substance to the pigment product prepared in step S3, adjust the pH to 9 to 11, evaporate part of the alcohol solvent contained in the pigment product, add water, filter, wash the filter cake with water, dry and crush to prepare a transparent heterocyclic organic pigment.

[0075] In one specific example, the method for preparing the covering heterocyclic organic pigment comprises the following steps:

[0076] S1. Dissolving the crude pigment in polyphosphoric acid at 100°C to 130°C for 2-5h, wherein the weight ratio of the crude pigment to the polyphosphoric acid is 1:4.5 to 7, and the mass percentage of the polyphosphoric acid, calculated as H3PO4, is 110% to 118%; preparing a reaction solution;

[0077] S2. The reaction solution prepared in step S1 is precipitated in 5% to 30% by mass of dilute phosphoric acid at a precipitation temperature of 0°C to 110°C. The mass ratio of the crude pigment in the reaction solution to the dilute phosphoric acid is 1:6 to 10. After precipitation, a filtrate and a filter cake are prepared by filtration. The solid content of the filter cake is 25% to 45%, and the mass ratio of the dilute phosphoric acid in the filtrate is 40% to 60%. The filtrate in step S2 can be directly used for the preparation of various phosphates.

[0078] S3. The filter cake prepared in step S2 is treated under pressure in n-butanol and isobutanol at a pressure temperature of 120-140°C for 4-10 hours to prepare a pigmented product;

[0079] S4. At 30°C to 70°C, add an alkaline substance to the pigment product prepared in step S3, adjust the pH to 9 to 11, evaporate part of the alcohol solvent contained in the pigment product, add water, filter, wash the filter cake with water, dry and crush to prepare a transparent heterocyclic organic pigment.

[0080] In a second aspect of the present application, a heterocyclic organic pigment is provided, which is prepared by the preparation method of the heterocyclic organic pigment described in the first aspect.

[0081] The heterocyclic organic pigment prepared by the preparation method of the present application has high transparency and hue adjustability and excellent hiding performance. At the same time, the heterocyclic organic pigment of the present application has a wide chromatographic range, bright color, high tinting power and good dispersibility.

[0082] The third aspect of the present application provides an application of the heterocyclic organic pigment described in the second aspect of the present application in the fields of coatings, inks, plastics, rubber, fabric printing and cosmetics.

[0083] The following are specific examples. Unless otherwise specified, the raw materials used in the examples are all commercially available products.

[0084] Example 1

[0085] Example 1 of the present application provides a method for preparing a dioxazine pigment, comprising the following steps:

[0086] (1) In a 250 mL three-necked flask equipped with a thermometer and a stirrer, 250 g of polyphosphoric acid (the concentration of polyphosphoric acid is 110% based on phosphoric acid content) is added in sequence, the temperature is raised to 105° C., 50 g of crude dioxazine pigment is added, the temperature is raised to 125° C., and stirred for 3 hours to allow sufficient dissolution to prepare a reaction solution.

[0087] (2) At 25°C, add 300g of 10% dilute phosphoric acid into a 1000mL beaker. While stirring, add the reaction solution prepared in step (1) into the dilute phosphoric acid, stir for 3h, and filter after precipitation. The mother liquor after filtration is recovered for use as phosphate, and the filter cake is washed with water until the mass percentage of phosphoric acid in the washing liquid is 10%. The filter cake is washed and drained, and the solid content is measured to be 35%, which is set aside.

[0088] (3) In a three-necked flask with a reflux device, add the filter cake obtained in step (2) to 600g of methanol, heat to 110°C, reflux for 15 hours, cool to 55°C, add sodium hydroxide, adjust the pH to 11, stir for 2 hours, change to distillation, distill 300g of methanol, add 300g of water, stir evenly, filter, wash with water, and recover methanol from the mother liquor. Finally, dry the filter cake to obtain a transparent dioxazine pigment (PV23).

[0089] Example 2

[0090] Example 2 of the present application provides a method for preparing a dioxazine pigment, comprising the following steps:

[0091] (1) In a 250 mL three-necked flask equipped with a thermometer and a stirrer, 250 g of polyphosphoric acid was added in sequence, the temperature was raised to 105° C., 48 g of crude dioxazine pigment and 2 g of Pigment Red 122 (PR122) were added, the temperature was raised to 125° C., and the mixture was stirred for 3 hours to allow sufficient dissolution to prepare a reaction solution.

[0092] (2) At 25°C, add 300g of 10% dilute phosphoric acid into a 1000mL beaker. While stirring, add the reaction solution prepared in step (1) into the dilute phosphoric acid, stir for 3h, and filter after precipitation. The mother liquor after filtration is recovered for use as phosphate, and the filter cake is washed with water until the mass percentage of phosphoric acid in the washing liquid is 10%. The filter cake is washed and drained, and the solid content is measured to be 35%, which is set aside.

[0093] (3) In a three-necked flask with a reflux device, the filter cake obtained in step (2) was added to 600g of methanol, the temperature was raised to 110°C, refluxed for 15 hours, cooled to 55°C, sodium hydroxide was added, the pH was adjusted to 11, stirred for 2 hours, and then distilled to remove 300g of methanol, 300g of water was added, stirred evenly, filtered, washed with water, and the mother liquor was used to recover methanol. Finally, the filter cake was dried to obtain a transparent dioxazine pigment (PV23). Compared with Example 1, the dioxazine pigment (PV23) prepared in Example 2 was a quaternary red phase.

[0094] Example 3

[0095] Example 3 of the present application provides a method for preparing a dioxazine pigment, comprising the following steps:

[0096] (1) In a 250 mL three-necked flask equipped with a thermometer and a stirrer, 250 g of polyphosphoric acid was added in sequence, the temperature was raised to 105° C., 48 g of crude dioxazine pigment and 2 g of Pigment Blue 60 (PB60) were added, the temperature was raised to 125° C., and the mixture was stirred for 3 hours to allow the mixture to dissolve fully, thereby preparing a reaction solution.

[0097] (2) At 25°C, add 300g of 10% dilute phosphoric acid into a 1000mL beaker. While stirring, add the reaction solution prepared in step (1) into the dilute phosphoric acid, stir for 3h, and filter after precipitation. The mother liquor after filtration is recovered for use as phosphate, and the filter cake is washed with water until the mass fraction of phosphoric acid in the washing liquid is 10%. The filter cake is washed and drained, and the solid content is measured to be 35%, which is set aside.

[0098] (3) In a three-necked flask with a reflux device, the filter cake obtained in step (2) was added to 600g of methanol, the temperature was raised to 110°C, refluxed for 15 hours, cooled to 55°C, sodium hydroxide was added, the pH was adjusted to 11, stirred for 2 hours, and then distilled to remove 300g of methanol, 300g of water was added, stirred evenly, filtered, washed with water, and the mother liquor was used to recover methanol. Finally, the filter cake was dried to obtain a transparent dioxazine pigment (PV23). Compared with Example 1, the dioxazine pigment (PV23) prepared in Example 3 showed a five-level blue phase.

[0099] Example 4

[0100] Example 4 of the present application provides a method for preparing a dioxazine pigment, comprising the following steps:

[0101] (1) In a 250 mL three-necked flask equipped with a thermometer and a stirrer, 250 g of polyphosphoric acid was added in sequence, the temperature was raised to 105° C., 48 g of crude dioxazine pigment and 2 g of Pigment Red 122 (PR122) were added, the temperature was raised to 125° C., and the mixture was stirred for 3 hours to allow sufficient dissolution to prepare a reaction solution.

[0102] (2) At 25°C, add 300g of 10% dilute phosphoric acid into a 1000mL beaker. While stirring, add the reaction solution prepared in step (1) into the dilute phosphoric acid, stir for 3h and filter. The mother liquor after filtration is recovered for use as phosphate, and the filter cake is washed with water until the mass percentage of phosphoric acid in the washing liquid is 10%. The filter cake is washed and drained, and the solid content is measured to be 35%, which is set aside.

[0103] (3) In a three-necked flask with a reflux device, the filter cake obtained in step (2) was added to 600g of n-butanol, the temperature was raised to 140°C, the pressure was maintained for 8h, the temperature was lowered to 55°C, sodium hydroxide was added, the pH was adjusted to 11, and the mixture was stirred for 2 hours. Then, 300g of n-butanol was distilled out, 300g of water was added, the mixture was stirred evenly, filtered, washed with water, and the mother liquor was used to recover n-butanol. Finally, the filter cake was dried to obtain a transparent dioxazine pigment (PV23). Compared with Example 2, the dioxazine pigment (PV23) prepared in Example 4 had a five-level covering.

[0104] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A method for preparing a heterocyclic organic pigment, characterized in that: The following steps are involved: Dissolving a crude heterocyclic organic pigment in polyphosphoric acid to prepare a crude solution; The crude product solution is mixed with dilute phosphoric acid to precipitate solids, which are filtered and the filter cake is collected; The filter cake is subjected to pressurization or reflux treatment in an alcohol solvent to prepare a pigment product; removing impurities from the pigmented product in an alkaline medium to prepare the heterocyclic organic pigment; The process parameters for pressurizing or refluxing the filter cake in an alcohol solvent include: refluxing the filter cake in an alcohol solvent having 1 to 2 carbon atoms for 6 to 15 hours; or The filter cake is subjected to a pressure treatment in an alcohol solvent having 3 to 4 carbon atoms at a pressure temperature of 120° C. to 140° C.; The crude heterocyclic organic pigment comprises the following components in parts by weight: 90 to 100 parts of crude dioxazine pigment, 0 to 10 parts of crude color pigment; The crude tinting pigment comprises a crude quinacridone pigment or a crude anthraquinone pigment.

2. The method for preparing a heterocyclic organic pigment according to claim 1, characterized in that: The mass ratio of the crude heterocyclic organic pigment to the polyphosphoric acid is 1:4.5-7; Calculated by phosphoric acid content, the mass fraction of the polyphosphoric acid in the aqueous solution is 110% to 118%.

3. The method for preparing a heterocyclic organic pigment according to claim 1, characterized in that: The process parameters for dissolving the crude heterocyclic organic pigment in polyphosphoric acid include: a dissolution temperature of 100°C to 130°C.

4. The method for preparing a heterocyclic organic pigment according to claim 1, characterized in that: The mass fraction of the dilute phosphoric acid is 5% to 30%, and the mass ratio of the crude heterocyclic organic pigment to the dilute phosphoric acid is 1:6 to 10.

5. The method for preparing a heterocyclic organic pigment according to any one of claims 1 to 4, characterized in that: The crude product solution is mixed with dilute phosphoric acid, and the process parameters for precipitating solids include: a precipitation temperature of 0°C to 110°C.

6. The method for preparing a heterocyclic organic pigment according to any one of claims 1 to 4, characterized in that: In the step of pressurizing or refluxing the filter cake in an alcohol solvent, the mass ratio of the filter cake to the alcohol solvent is 1:8-20.

7. The method for preparing a heterocyclic organic pigment according to any one of claims 1 to 4, characterized in that: The pH of the alkaline medium is 9-11.

8. A heterocyclic organic pigment, characterized in that The pigment is prepared by the method for preparing the heterocyclic organic pigment according to any one of claims 1 to 7.

9. Use of the heterocyclic organic pigment according to claim 8 in the fields of coatings, inks, plastics, rubber, fabric printing and cosmetics.