Production method of environment-friendly pigment red 146

Abstract

According to the brand new environment-friendly pigment red 146 production method provided by the invention, on the basis of a traditional production process, a material after coupling reaction is subjected to filter pressing and washing, organic impurities and salt are removed, then a special high-speed pulping machine is used for performing high-speed pulping on a filter cake, high-temperature and pressure treatment is performed in a pressure kettle, and the pigment red 146 is obtained. According to the process, pigment particles are more sufficient in crystal transformation, more stable in crystal form and narrower in particle size distribution, the chemical resistance, the light resistance, the heat resistance and the like of the obtained pigment red 146 are all higher than the industrial standard, and the pigment red 146 does not contain forbidden aromatic amine or toxic substances.

Description

Technical Field

[0001] This invention belongs to the field of chemical engineering and relates to monoazo dyes in organic pigments, specifically a production method for an environmentally friendly pigment, Red 146. Background Technology

[0002] Pigment Red 146 is a monoazo pigment with the chemical formula C. 33 H 27 ClN4O6 has a molecular weight of 611.04. Its chemical name is N-(4-chloro-2,5-dimethoxyphenyl)-3-hydroxy-4-[[2-methoxy-5-[(phenylamino)formyl]phenyl]azo]naphthalene-2-carboxamide. Its chemical formula is shown below:

[0003]

[0004] Pigment Red 146 exhibits a bluish-red hue, slightly more yellowish than Pigment Red 57:1. It is primarily used in printing inks and coatings, and its solvent resistance and sterilization properties are superior to Pigment Red 57:1. It possesses excellent color stability and lightfastness, producing a vibrant red effect.

[0005] In industrial production, the manufacturing process of Pigment Red 146 typically involves two steps: diazotization and coupling reactions. This usually involves the oxidation of iron salts with organic reagents to obtain the product. During production, reaction yield, particle size, and color properties are key factors affecting the performance of azo pigments. These reactions need to be carried out under specific temperature and pH conditions to ensure the quality and performance of the product. Currently, the manufacturing process of Pigment Red 146 uses a traditional batch process with a batch reactor, which presents several challenges, including a yield of less than 95%, large particle size, and uneven particle size distribution.

[0006] 1. Insufficient reaction yield: Traditional batch processes have a yield of less than 95%, resulting in low production efficiency.

[0007] 2. Uneven particle size distribution: The pigment has a large particle size and uneven distribution, which will affect its performance in application.

[0008] 3. Batch performance differences: Due to the limitations of traditional processes, different batches of pigments may have different performance characteristics, affecting the stability of product quality.

[0009] 4. Lack of research on nanoscale preparation: With the development of inkjet printing technology, the demand for nanoscale pigments has increased, but at present, there is a lack of in-depth research on the preparation methods of nanoscale pigment Red 146 in China.

[0010] 5. High viscosity of pigment paste: In the application of pigment printing paste, the pigment red 146 has a high viscosity and poor dispersion stability, which affects its performance.

[0011] 6. Solubility issues: The poor solubility of the cromoglycin intermediate AS-LC directly affects the effectiveness of the coupling reaction, and consequently the performance of the product.

[0012] 7. Difficulty in controlling the temperature during the heating and crystallization color change process: In the post-processing, it is difficult to control the temperature during the heating and crystallization color change process. If the temperature is too high, the transparency will be poor, and if the temperature is too low, the color will be dark, and the fluidity and gloss will be poor.

[0013] 8. Surfactant selection: Different surfactants have different effects on the dispersibility and performance of Pigment Red 146. Selecting the right surfactant is the key to improving product quality.

[0014] In summary, the production of Pigment Red 146 faces multiple challenges, including reaction efficiency, particle size control, batch consistency, nanotechnology application, optimization of pigment properties, solubility issues, control of the crystal transformation process, and surfactant selection. Solving these problems requires a comprehensive approach, considering process improvements, technological innovation, and advancements in materials science, to achieve high-quality production of Pigment Red 146.

[0015] CN104479406A discloses an industrial production method for transparent, high-gloss pigment red 146 for solvent-based inks. This method uses 2-hydroxy-3-naphthoyl-(4-chloro-2,5-dimethoxy)aniline mixed with liquid alkali at a ratio of 1:2-3, and adds a co-solvent and sodium acetate to the diazo component to ensure the reaction system is under weakly acidic conditions, resulting in a complete and stable reaction. By controlling the emulsifier dosage, the crystallization effect is controlled, resulting in a product with concentrated particle size distribution, bright color, good flowability, and high transparency. This invention features mild reaction conditions, low equipment requirements, short reaction time, and uses common emulsifiers with minimal application difficulty, aligning with the theme of novel environmental protection. The obtained product has a bright color, heat resistance of 220℃ / 5min, and lightfastness rating of 5. CN110283475A discloses a preparation method for pigment red 146, which uses a 25-35% concentration of ammonium nitrite solution to obtain pigment red 146 with uniform particle size, low viscosity, and good dispersibility.

[0016] With increasing emphasis on environmental protection and safety, the EU Regulation AP(89)1 of 1935 / 2004 / EC has strict limits on the residual harmful substances in pigments used in contact with the human body, particularly for pigments used in plastic and food packaging inks. The limits are as follows: lead ≤100ppm; antimony ≤100ppm; arsenic ≤100ppm; barium ≤100ppm; cadmium ≤100ppm; chromium ≤1000ppm; mercury ≤50ppm; aromatic amines ≤500ppm. Controlling aromatic amines is crucial. In recent years, several advanced pigment manufacturers in the EU and the US have reported reducing the content of harmful aromatic amines in azo pigments from an average of 1000-5000ppm to 500ppm, and have launched corresponding specifications of pigments on the market.

[0017] On August 1, 2008, the European Union officially implemented the REACH regulation for the purposes of protecting human health and the environment, maintaining and improving the competitiveness of the EU chemical industry, and increasing the transparency of chemical information. The regulation stipulates that all chemical substances with an annual production or import volume exceeding 1 tonne must be registered, and chemical substances with an annual production or import volume exceeding 10 tons are required to provide a series of registration documents, including a chemical safety data sheet, a safety assessment report, and a risk assessment. Subsequently, a specific safety regulation, AP(89)1, was introduced for the pigment sector, which sets clear limits on the residual heavy metals and aromatic amines in pigments used in plastics and food packaging inks. Pigments that do not meet these requirements cannot be used in this sector. China, as the world's main pigment producer, accounts for approximately 70% of the world's total annual production. The AP(89)1 regulation has become a trade barrier for entry into the EU market. Existing Pigment Red 146 products contain high levels of toxic aromatic amines, heavy metals, and salts, making them unable to meet European and American export standards and domestic requirements for use in food packaging, home decoration, and other fields. Furthermore, existing Pigment Red 146 products are mostly used in the traditional ink and coating industries, which can cause some environmental pollution and have many adverse effects due to a lack of safety and environmental friendliness.

[0018] Therefore, improvements and upgrades can be made to the existing production method of Pigment Red 146 to achieve a production process free of heavy metals and banned aromatic amines, environmentally friendly with bright colors, light and heat resistance, long-lasting color retention, and good natural degradation. This can greatly promote the production and manufacturing of environmentally friendly pigments in China and help break down trade barriers. Summary of the Invention

[0019] To address the problems existing in the prior art, the purpose of this invention is to provide a method for producing an environmentally friendly pigment, Red 146, wherein the method includes the following steps:

[0020] S1, Diazotization reaction

[0021] Dilute 30% hydrochloric acid with water, then add 3-amino-4-methoxybenzoylaniline (KD), and stir until completely dissolved. Then add ice to cool to 3-5°C, and add 20-30% sodium nitrite aqueous solution to carry out a medium diazotization reaction for 1-3 hours. The gas generated during the reaction is treated as waste gas. After the reaction is completed, add ice and water to maintain the temperature at 3-8°C for later use.

[0022] S2, Coupling reaction

[0023] Dilute 30% alkali with water, heat to 75-80℃ with high-temperature steam, add naphthol AS-LC, stir until completely dissolved, add 5000kg of crushed ice and 5000L of water through the feed port to cool to 20-40℃, then add a mixed aqueous solution of 60% acetic acid and 58% sodium acetate for acid precipitation, and continue until the pH is 5-6 to obtain the coupling solution for later use;

[0024] Add the obtained coupling solution to the diazonium solution obtained in step S1 and carry out the coupling reaction for 0.5 to 1.5 hours. During the reaction, maintain the reaction temperature at 40-50℃ and the pH at 5-5.5, and stir for 1 hour.

[0025] S3, Filtration, Washing

[0026] The coupling product obtained in S2 is filtered by a filter press to separate the water from the obtained pigment. The wastewater generated by the filter press is sent to the sewage treatment plant for treatment. Water is added to the filter press to rinse the material until it is neutral. The wastewater generated after rinsing is sent to the sewage treatment plant for treatment. The filter cake is ready for use.

[0027] S4, Post-processing

[0028] Add the filter cake obtained from S3 to the reactor, add water to make up to 70-80% of the reactor volume, then add surfactant, and pulverize at 1000-1500 rpm for 60 minutes. Raise the temperature to 80-90℃ and keep it at that temperature for 1 hour. Set aside for use.

[0029] S5, pressure filtration, fine washing

[0030] The product obtained from S4 is filtered again by a filter press. The wastewater generated by the filter press is sent to the sewage treatment plant for treatment. Water is added to the filter press to rinse the material until it is neutral. After rinsing, the material is blown off and set aside for use. The wastewater generated after rinsing and blowing off is sent to the sewage treatment plant for treatment.

[0031] S6. Drying and pulverizing

[0032] The filter cake obtained from S5 is dried at a temperature of 80-85℃ for 12 hours. The gas generated during drying is treated by dust removal. The collected dust is mixed with the filter cake and then dried until the moisture content is 0.5-1.5%. The uncollected gas is treated as waste gas. After drying, the finished pigment Red 146 is obtained.

[0033] Preferably, the surfactant is prepared by Huntsman L-207 and acetoacetanilide at 85-90 degrees Celsius for 6 hours.

[0034] Preferably, the feeding ratio of red base KD, sodium nitrite and hydrochloric acid in S1 is 1:0.8-1.5:3-4, more preferably 1:1.0-1.3:3.3-3.8, and most preferably 1:1.02:3.5.

[0035] Preferably, the ratio of naphthol AS-LC to alkali in S2 is 1:3 to 4, more preferably 1:3.3 to 3.8, and most preferably 1:3.6.

[0036] Preferably, liquid alkali or soda ash is used in S2, and liquid alkali 546 is preferred.

[0037] Preferably, in S2, the pH is adjusted by hydrochloric acid and alkali, and the pH is stabilized by acetic acid.

[0038] Preferably, the ratio of acetic acid to sodium acetate precipitated in S2 is 1:0.3 to 0.8, more preferably 1:0.5 to 0.7, and most preferably 1:0.6.

[0039] Preferably, in step S5, the material is rinsed until the conductivity is ≤100μs / cm.

[0040] Preferably, in step S6, the filter cake is dried to a moisture content of ≤1.0%.

[0041] Preferably, the dried material obtained in S6 is further subjected to ultrafine pulverization.

[0042] Compared with existing technologies, this invention provides a novel environmentally friendly production method for Pigment Red 146. This method, based on traditional production processes, involves pressure filtration and washing of the material after the coupling reaction to remove organic impurities and salts. Then, a dedicated high-speed pulper is used to pulp the filter cake at high speed, followed by high-temperature and pressure treatment in a pressure vessel, and further washing with pure water. This process results in more complete crystallization of pigment particles, more stable crystal forms, and a narrower particle size distribution. The resulting Pigment Red 146 exhibits chemical resistance, lightfastness, and heat resistance exceeding industry standards, and contains no prohibited aromatic amines or toxic substances. Furthermore, the surfactant used in this invention yields Pigment Red 146 with higher color payoff and gloss. Performance test data also show that the Pigment Red 146 produced by the method provided by this invention has a bright color, good lightfastness and heat resistance, and long-lasting colorfastness. The pigment does not contain heavy metals or prohibited aromatic amines, has good biodegradability, and can be widely used in emerging fields such as environmentally friendly water-based pigments, inkjet printing, powder coatings, and high-end automotive (marine) anti-corrosion paints, especially in the food industry, where it is environmentally friendly and safe.

[0043] Terminology Explanation

[0044] When the term "about" is applied to parameters such as pH, concentration, temperature, etc., it indicates that the parameter can vary by ±10%, and sometimes more preferably within ±5%. As those skilled in the art will understand, when a parameter is not critical, figures are usually given for illustrative purposes only, not as limitations. Attached Figure Description

[0045] Figure 1 Flowchart of the production method of environmentally friendly pigment Red 146 provided by the present invention;

[0046] Figure 2 Photograph of the environmentally friendly pigment Red 146 obtained in the example. Detailed Implementation

[0047] The present invention will be further described in detail and completely below with reference to embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] Unless otherwise specified, the experimental methods described in the following embodiments shall be performed according to the manufacturer's recommended conditions. Unless otherwise specified, all reagents involved in the embodiments of this invention are commercially available products and can be purchased through commercial channels.

[0049] The main materials involved in the embodiments of this invention are as follows:

[0050] Experimental reagents

[0051]

[0052] Example 1

[0053] ① Diazotization reaction

[0054] 15,000L of tap water was added to the diazo tank through a pipeline. 570kg of 30% hydrochloric acid was added to the diazo tank through a metering tank. 550kg of red-based KD powder was added to the diazo tank through the feeding port and stirred until completely dissolved. 4,000kg of crushed ice was added through the feeding port to cool the temperature to 3-5℃. A 20-30% sodium nitrite aqueous solution (prepared by dissolving 168kg of 99% sodium nitrite in 500kg of water in a dissolving tank) was added to the diazo tank from the sodium nitrite metering tank using a high-level difference. The diazotization reaction was carried out for 1 hour. The gas generated during the reaction was treated as waste gas. After the reaction, the diazo liquid waited in the diazo tank to enter the coupling section.

[0055] ② Coupling reaction

[0056] Add 10,000L of tap water into the dissolving tank through a pipe. Add 293kg of 30% liquid alkali into the dissolving tank through the high-level liquid tank. Then, heat the dissolving tank by introducing steam through a pipe to reach a temperature of 75-80℃. Add 822kg of naphthol AS-LC powder into the dissolving tank through the feeding port and stir for 30 minutes until completely dissolved. Then, add 3,000kg of crushed ice and 3,000L of water into the dissolving tank through the feeding port, cool the tank to 20-40℃, and then place it into the coupling tank.

[0057] 1500 kg of water, 227 kg of 60% acetic acid, and 150 kg of 58% sodium acetate were placed in a dissolving tank. The mixture was then transferred to a coupling tank using the liquid level difference for acid precipitation. The pH was then adjusted to 5-6, and coupling was allowed to proceed.

[0058] The prepared diazo solution is added to the coupling solution from the diazo tank using the liquid level difference, and the coupling reaction is carried out for 1.5 hours. The temperature is controlled at 40-50℃ and the pH value is 5-5.5. After stirring for 1 hour, the mixture is filtered in a filter press.

[0059] ③ Filter press and rinsing section

[0060] The material from the coupling section is pumped into a filter press for filtration. The wastewater generated during filtration is treated at a wastewater treatment plant. 30,000L of tap water is added through a pipeline to the plate and frame filter press to rinse the material until it reaches neutrality. The resulting wastewater is also treated at the wastewater treatment plant. The filter cake from the filter press is sent to the post-processing section.

[0061] ④ Post-processing section

[0062] Huntsman L-207 and acetoacetanilide were heated at 85-90 degrees Celsius for 6 hours to obtain a surfactant. The filter cake was added to a coupling tank, along with 5000L of tap water and 70kg of surfactant. The mixture was stirred for 1 hour, heated to 80-90 degrees Celsius, and held at that temperature for 60 minutes before being filtered in a filter press.

[0063] ⑤ Filtration and washing section

[0064] The post-processed material is pumped into a filter press for filtration. The wastewater generated from the filtration process is treated at a wastewater treatment plant. 10,000L of tap water is added through a pipeline to the plate and frame filter press to rinse the material. Then, an air compressor blows the material off the plate and frame filter press through a pipeline. The wastewater generated after rinsing and blowing off is treated at a wastewater treatment plant.

[0065] ⑥ Drying section

[0066] The filter cake from the filter press is fed into a belt dryer via a conveyor belt for drying. The gas generated during drying is collected by a two-stage wet packed tower dust collector. After drying, the finished pigment Red 146 is obtained. (See finished product photo for details.) Figure 2 .

[0067] Performance testing

[0068] 1. The obtained finished pigment Red 146 was tested according to industry standard HG / T5371-2018, and the test results are as follows:

[0069]

[0070] 2. Detection of heavy metals and aromatic amines

[0071] The finished product was sent to SGS for testing, and the test results are as follows.

[0072] (1) Test method for phthalate (18P) content: Refer to GB31604.30-2016 and use GC-MS analysis.

[0073] Test Project CAS NO. MDL (mg / kg) Test results (mg / kg) Dimethyl phthalate (DMP) 131-11-3 5.00 ND Diethyl phthalate (DEP) 84-66-2 5.00 ND diallyl phthalate (DAP) 131-17-9 5.00 ND Diisobutyl phthalate (DIBP) 84-69-5 5.00 ND Dibutyl phthalate (DBP) 84-74-2 5.00 ND Di(2-ethylhexyl) phthalate (DEHP) 117-81-7 5.00 ND Di(2-methoxy)ethyl phthalate (DMEP) 117-82-8 5.00 ND Di(4-methyl-2-pentyl) phthalate (BMPP) 146-50-9 5.00 ND Di(2-ethoxy)ethyl phthalate (DEEP) 605-54-9 5.00 ND Diamyl phthalate (DPP) 131-18-0 5.00 ND Dihexyl phthalate (DNHP / DHXP) 84-75-3 5.00 ND Butyl benzyl phthalate (BBP) 85-68-7 5.00 ND Di(2-butoxy)ethyl phthalate (DBEP) 117-83-9 5.00 ND Dicyclohexyl phthalate (DCHP) 84-61-7 5.00 ND Diphenyl phthalate (DPhP) 84-62-8 5.00 ND Di-n-octyl phthalate (DNOP) 117-84-0 5.00 ND Dinolide phthalate (DNP) 84-76-4 5.00 ND Diisononyl phthalate (DINP) 68515-48-0 50.0 ND

[0074] Remark:

[0075] 1. ND = Not detected; MDL = Method detection limit; 1 mg / kg = 0.0001%.

[0076] 2. The test results are displayed as the sample weight content.

[0077] (2) EN 71-3:2019+A1:2021 Migration test method for specific elements: Refer to EN 71-3:2019+A1:2021 and use ICP-OES and IC-UV / Vis analysis and testing.

[0078]

[0079] Remark:

[0080] 1. ND = Not detected; MDL = Method detection limit; 1 mg / kg = 0.0001%.

[0081] 2. The results for soluble tin should not exceed 2.5 mg / kg, and the results for organotin should refer to the results for soluble tin.

[0082] 3. The test results are displayed as the sample weight content.

[0083] (3) Test method for nitrogen dye content: GC-MS was used for analysis and testing in accordance with EN 14362-1:2017 and EN 14362-3:2017.

[0084] Test Project CAS NO. MDL (mg / kg) Test results (mg / kg) aniline 62-53-3 5 ND o-Toluidine 95-53-4 5 ND 2,4-Dimethylaniline 95-68-1 5 ND 2,6-Dimethylaniline 87-62-7 5 ND o-aminoanisole 90-04-0 5 ND p-Chloroaniline 106-47-8 5 ND 2-Methoxy-5-methylaniline 120-71-8 5 ND 2,4,5-Trimethylaniline 137-17-7 5 ND 4-Chlorotoluidine 95-69-2 5 ND 2,4-Diaminotoluene 95-80-7 5 ND 2,4-Diaminoanisole 615-05-4 5 ND β-naphthylamine 91-59-8 5 ND 5-Nitro-o-Toluidine 99-55-8 5 ND 4-Aminobiphenyl 92-67-1 5 ND 4-Aminoazobenzene 60-09-3 5 ND 4,4-Diaminodiphenyl ether 101-80-4 5 ND p-Diaminobiphenyl 92-87-5 5 ND 4,4-Diaminodiphenylmethane 101-77-9 5 ND o-aminoazotoluene 97-56-3 5 ND 3,3-Dimethyl-4,4-diaminodiphenylmethane 838-88-0 5 ND 3,3-Dimethylbenzidine 119-93-7 5 ND 4,4-Diaminodiphenyl sulfide 139-65-1 5 ND 3,3-Dichlorobenzidine 91-94-1 5 ND 4,4-Methylene-di-(2-chloroaniline) 101-14-4 5 ND 3,3-Dimethoxybenzidine 119-90-4 5 ND

[0085] Remark:

[0086] 1. ND = Not detected; MDL = Method detection limit; 1 mg / kg = 0.0001%.

[0087] 2. The test results are displayed as the sample weight content.

[0088] (4) Detection method for sulfonated aromatic amines: Refer to the Council of European Ministerial Resolution AP(89)1.

[0089]

[0090] Remark:

[0091] (1)*The list of sulfonated aromatic amines to be tested is shown in the table below. The final results are calculated as aminobenzenesulfonic acid.

[0092] No. Sulfonated aromatic amines CAS No. 1 2-Amino-4-chloro-5-methylbenzenesulfonic acid 88-51-7 2 2-Amino-5-chloro-4-methylbenzenesulfonic acid 88-53-9 3 2-Amino-1-naphthalenesulfonic acid 81-16-3 4 2-Amino-5-methylbenzenesulfonic acid 88-44-8 5 2-Nitro-4-sulfonoaniline 616-84-2 6 2-Amino-4,5-dichlorobenzenesulfonic acid 6331-96-0 7 4-Amino-2,5-dimethoxy-N-phenylbenzenesulfonamide 52298-44-9 8 Methylsulfonamide criscitin 49564-57-0

[0093] (5) Aromatic amine detection method: Refer to the Council of European Ministerial Resolution AP(89)1.

[0094]

[0095] Remark:

[0096] (1)*Calculated as aniline.

[0097] Unless otherwise stated, compliance determination shall be performed using the simple acceptance (w=0) binary decision rule, referring to ILAC-G8:09 / 2019.

[0098] Finally, it is necessary to state that the above embodiments are only used to further illustrate the technical solution of the present invention in detail, and should not be construed as limiting the scope of protection of the present invention. Any changes, modifications, substitutions, combinations, or simplifications made by those skilled in the art without departing from the scope of the technical solution of this application using the above-disclosed technical content should be considered as equivalent substitutions and are included within the scope of protection of the present invention.

Claims

1. A method for producing an environmentally friendly pigment, Red 146, characterized in that, The method includes the following steps: S1, Diazotization reaction Dilute 30% hydrochloric acid with water, then add 3-amino-4-methoxybenzoylaniline (KD), and stir until completely dissolved. Then add ice to cool to 3-5°C, and add 20-30% sodium nitrite aqueous solution to carry out a medium diazotization reaction for 1-3 hours. The gas generated during the reaction is treated as waste gas. After the reaction is completed, add ice and water to maintain the temperature at 3-8°C for later use. S2, Coupling reaction Dilute 30% alkali with water, heat to 75-80℃ with high-temperature steam, add naphthol AS-LC, stir until completely dissolved, add 5000kg of crushed ice and 5000L of water through the feed port to cool to 20-40℃, then add a mixed aqueous solution of 60% acetic acid and 58% sodium acetate for acid precipitation, and continue until the pH is 5-6 to obtain the coupling solution for later use; Add the obtained coupling solution to the diazonium solution obtained in step S1 and carry out the coupling reaction for 0.5 to 1.5 hours. During the reaction, maintain the reaction temperature at 40-50℃ and the pH at 5-5.5, and stir for 1 hour. S3, Filtration, Washing The coupling product obtained in S2 is filtered by a filter press to separate the water from the obtained pigment. The wastewater generated by the filter press is sent to the sewage treatment plant for treatment. Water is added to the filter press to rinse the material until it is neutral. The wastewater generated after rinsing is sent to the sewage treatment plant for treatment. The filter cake is ready for use. S4, Post-processing Add the filter cake obtained from S3 to the reactor, add water to make up to 70-80% of the reactor volume, then add surfactant, and pulverize at 1000-1500 rpm for 60 minutes. Raise the temperature to 80-90℃ and keep it at that temperature for 1 hour. Set aside for use. S5, pressure filtration, fine washing The product obtained from S4 is filtered again by a filter press. The wastewater generated by the filter press is sent to the sewage treatment plant for treatment. Water is added to the filter press to rinse the material until it is neutral. After rinsing, the material is blown off and set aside for use. The wastewater generated after rinsing and blowing off is sent to the sewage treatment plant for treatment. S6. Drying and pulverizing The filter cake obtained from S5 is dried at a temperature of 80-85℃ for 12 hours. The gas generated during drying is treated by dust removal. The collected dust is mixed with the filter cake and then dried until the moisture content is 0.5-1.5%. The uncollected gas is treated as waste gas. After drying, the finished pigment Red 146 is obtained.

2. The production method according to claim 1, characterized in that, The surfactant was prepared by incubating Huntsman L-207 and acetoacetanilide at 85-90 degrees Celsius for 6 hours.

3. The production method according to claim 1, characterized in that, The feeding ratio of red-based KD, sodium nitrite, and hydrochloric acid in S1 is 1:0.8-1.5:3-4.

4. The production method according to claim 1, characterized in that, In S2, the ratio of cromoglycinate AS-LC to alkali is 1:3 to 4.

5. The production method according to claim 1, characterized in that, The alkali used in S2 is either liquid alkali or soda ash.

6. The production method according to claim 1, characterized in that, In S2, the pH is adjusted by hydrochloric acid and alkali, and the pH is stabilized by acetic acid.

7. The production method according to claim 1, characterized in that, The ratio of acetic acid to sodium acetate precipitated in S2 is 1:0.3 to 0.

8.

8. The production method according to claim 1, characterized in that, In S5, the material is rinsed until the conductivity is ≤100μ. s / cm.

9. The production method according to claim 1, characterized in that, In S6, the filter cake is dried to a moisture content of ≤1.0%.

10. The production method according to claim 1, characterized in that, The dried material obtained in S6 is then subjected to ultrafine pulverization.

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