A high-diffusion environmentally friendly azo pigment and preparation method thereof

Abstract

The present application relates to the field of pigment production technology, and in particular to a high-diffusion environmentally friendly azo pigment and a preparation method thereof. A preparation method of a high-diffusion environmentally friendly azo pigment, firstly prepares a diazo liquid, mixes and dissolves 2-chloro-4-aminotoluene-5-sulfonic acid with ammonia water, adds hydrochloric acid and sodium nitrite aqueous solution to react, and obtains a diazo liquid. Then a coupling solution is prepared, and after mixing 2-hydroxy-3-naphthoic acid with sodium hydroxide, a functional additive and a coupling agent are added to obtain a coupling liquid. Next, a coupling reaction is carried out, and a diazo liquid, a coupling liquid and a surfactant are mixed and reacted, and the reaction end point pH is controlled to be 8.5-9.5 to obtain a coupling product. Finally, a strontium chloride aqueous solution, calcium carbonate are added and filtered, washed with water, dried and crushed to obtain a high-diffusion environmentally friendly azo pigment. The preparation method of the present application significantly improves the various performance indicators of azo pigments through the synergistic effect of various materials and the comprehensive use of technical means, so that it has important application value in the field of environmental protection and high-performance pigments.

Description

Technical Field

[0001] The present application relates to the technical field of pigment production, and in particular to a high-diffusion environmentally friendly azo pigment and a preparation method thereof. Background Art

[0002] Azo pigments are insoluble organic substances containing azo groups in their molecular structure. They are brightly colored and inexpensive, and are widely used in rubber, plastics, coatings and other fields.

[0003] With the rapid development of new energy technologies, the requirements for pigments in high-viscosity adhesives such as battery pack sealants and potting adhesives are increasing. Traditional pigments have poor dispersion in high-viscosity adhesives, resulting in unsatisfactory dyeing effects, and there are also many deficiencies in tinting strength, heat resistance, wear resistance, and water resistance.

[0004] Chinese patent CN200510038760.2 discloses a process for preparing pigment red, characterized in that it comprises the following steps: dissolving dye, dissolving intermediate copper sulfate, dissolving intermediate sodium sulfate and sodium ferroxanthate, mixing, rinsing with filter press, and discharging from the filter press to obtain semi-solid pigment red. The process uses cheap copper sulfate, sodium sulfate and sodium ferroxanthate as intermediates to react with dye, which greatly reduces the overall production cost. The process structure is simple, but the pigment prepared by the process has poor fluidity and uneven dispersion. Not only is the pigment gloss poor, but the water resistance and stability are also poor, and the scope of application is small, which cannot meet the current market demand for pigment performance. Summary of the invention

[0005] The purpose of the present application is to provide a high-diffusion environmentally friendly azo pigment and a preparation method thereof in view of the deficiencies of the current technology. The heat resistance, acid resistance and electrical insulation performance of the azo pigment are improved by introducing modified mica powder, and the thermal stability of the azo pigment can be enhanced by introducing silane-modified basic magnesium sulfate whiskers. The synergistic effect of modified mica powder and silane-modified basic magnesium sulfate whiskers is utilized to further improve the heat stability, acid resistance and electrical insulation performance of the azo pigment. The azo pigment obtained by co-coloration with Ca and Sr ions can significantly improve the tinting power and fluidity of the azo pigment. The introduction of surfactants can effectively prevent the aggregation of azo pigment particles through steric hindrance and electrostatic stabilization, thereby improving its high diffusion and fluidity. The azo pigment prepared by this method has excellent properties such as high gloss, tinting power, heat resistance, fluidity and water resistance.

[0006] In the first aspect, the present application provides a method for preparing a highly diffusible environmentally friendly azo pigment, using the following technical solution:

[0007] A method for preparing a highly diffusible environmentally friendly azo pigment comprises the following steps:

[0008] S1. The preparation of diazo liquid comprises the following steps, calculated by weight:

[0009] S11, in a diazo liquid reactor, 100-120 parts by mass of 2-chloro-4-aminotoluene-5-sulfonic acid, 40-50 parts by mass of 23% ammonia water, and 1300-1500 parts by mass of water are mixed evenly, and after the 2-chloro-4-aminotoluene-5-sulfonic acid is completely dissolved, a mixed solution A is obtained;

[0010] S12, adding 120-140 parts by mass of 35% hydrochloric acid to the mixed solution A, mixing well, adding ice cubes to cool to 0-5°C, adding 105-120 parts by mass of 33% sodium nitrite aqueous solution, mixing well, and keeping for 60-70 minutes to obtain a diazo solution;

[0011] S2, the preparation of the coupling solution, by weight, comprises the following steps:

[0012] 90-95 parts by weight of 2-hydroxy-3-naphthoic acid, 120-130 parts by weight of sodium hydroxide having a mass concentration of 24%, and 1500-1700 parts by weight of water are mixed uniformly, and then 13-15 parts by weight of a functional additive and 1-2 parts of a coupling agent are added, and the mixture is mixed uniformly to obtain a coupling liquid;

[0013] S3, coupling reaction, calculated by mass fraction, comprises the following steps:

[0014] S31, adding diazo liquid, coupling liquid and 4-5 parts of surfactant into the coupling compound dissolving kettle, mixing and reacting, controlling the pH at the reaction end point to be 8.5-9.5, to obtain a coupling product;

[0015] S32. Add 280-310 parts by mass of a 23% aqueous strontium chloride solution to the coupling product, stir for 90-120 minutes, heat to 80°C and further stir for 50-60 minutes, then add 30-35 parts by mass of 15% calcium carbonate and stir for 40-50 minutes, filter, wash with water, dry at 110°C for 24 hours and crush to obtain a highly diffuse environmentally friendly azo pigment.

[0016] By adopting the above technical scheme, the preparation of diazo liquid is first carried out, and after 2-chloro-4-aminotoluene-5-sulfonic acid is mixed and dissolved with ammonia water, hydrochloric acid and sodium nitrite aqueous solution are added to react to obtain diazo liquid. Then the coupling solution is prepared, and after 2-hydroxy-3-naphthoic acid is mixed with sodium hydroxide, functional additives and coupling agents are added to obtain coupling liquid. Next, a coupling reaction is carried out, and the diazo liquid, coupling liquid and surfactant are mixed and reacted, and the pH of the reaction end point is controlled to be 8.5-9.5 to obtain a coupling product. Finally, strontium chloride aqueous solution and calcium carbonate are added and filtered, washed with water, dried and crushed to obtain a high-diffusion environmentally friendly azo pigment. The azo pigment obtained by co-coloration using Ca and Sr ions significantly improves the tinting power and fluidity of the azo pigment. At the same time, the introduction of a surfactant can effectively prevent the aggregation between the azo pigment particles and improve its high diffusion and fluidity. In summary, the high-diffusion environmentally friendly azo pigment of the present application has excellent gloss, tinting power, heat resistance, fluidity and water resistance.

[0017] Preferably, in step S12, the sodium nitrite aqueous solution is added at a rate of 6-7 parts by mass / min.

[0018] Preferably, in step S2, the functional additive is prepared by mixing modified mica powder and silane-modified basic magnesium sulfate whisker in a mass ratio of 2:1.

[0019] By adopting the above technical scheme, these two materials play an important role in the preparation process of azo pigments, and there is a synergistic effect between them. First, modified mica powder is an inorganic filler with good heat resistance, acid resistance and electrical insulation properties. By introducing modified mica powder, the heat stability, acid resistance and electrical insulation properties of azo pigments can be effectively improved. In addition, modified mica powder can also improve the dispersibility and compatibility of azo pigments, thereby improving their high diffusivity and fluidity. Secondly, silane-modified basic magnesium sulfate whiskers are a flame retardant that can enhance the thermal stability of azo pigments. Basic magnesium sulfate molecules contain crystal water and OH groups. At heat-resistant temperatures, they can decompose to generate water vapor, effectively dilute the oxygen concentration around the matrix, and this process absorbs a lot of heat, which can effectively reduce the ambient temperature and can play a good flame retardant effect. Moreover, whisker-like basic magnesium sulfate is easy to form a continuous mesh structure in the matrix, which is the main reason why basic magnesium sulfate strengthens the matrix. In the preparation process of azo pigments, adding basic magnesium sulfate whiskers can significantly improve the adhesion and hardness of the pigment and improve the wear resistance of azo pigments. In summary, modified mica powder and silane-modified basic magnesium sulfate whiskers have a synergistic effect in the preparation of azo pigments. By introducing these two materials, the heat stability, acid resistance and electrical insulation properties of azo pigments can be further improved; at the same time, the adhesion, hardness and wear resistance of the pigments can also be improved. This makes the prepared azo pigments have higher gloss, tinting power, heat resistance, fluidity and water resistance and other excellent properties.

[0020] Preferably, the method for preparing the modified mica powder comprises the following steps:

[0021] S41. According to the mass fraction, 10 parts of mica powder with a particle size of 1 micron are placed in a muffle furnace, the temperature is increased to 400-500° C., and calcined for 1-2 hours. After the calcination, it is added to 30 parts of a sulfuric acid solution with a mass concentration of 35%, ultrasonically stirred for 50-60 minutes, and allowed to stand for precipitation. The precipitate is washed with deionized water until it is neutral to obtain hydroxylated mica powder;

[0022] S42, according to the mass parts, 0.8 parts of vinyl triethoxysilane, 50 parts of ethanol and 40 parts of water were mixed, and stirred to obtain a mixture A;

[0023] S43, adding hydroxylated mica powder to mixture A, then heating to 40°C, stirring at 200 r / min for 150 min, and finally filtering, washing, drying at 85°C, and grinding to obtain modified mica powder.

[0024] By adopting the above technical scheme, the modified mica powder prepared has a layer of organic film grafted on its surface, which changes from hydrophilic to hydrophobic, and has good dispersibility and compatibility. This helps to improve the heat stability and acid resistance of azo pigments. Modified mica powder has excellent electrical insulation properties, and introducing it into azo pigments can enhance the electrical insulation properties of the pigments. The synergistic effect of modified mica powder and silane-modified basic magnesium sulfate whiskers further improves the heat stability, acid resistance and electrical insulation properties of azo pigments. In summary, the modified mica powder plays a role in improving the heat stability, acid resistance, electrical insulation properties, tinting power, fluidity, high diffusivity and wear resistance in the preparation of azo pigments, and synergizes with silane-modified basic magnesium sulfate whiskers to further improve the performance of azo pigments.

[0025] Preferably, the silane-modified basic magnesium sulfate whisker is γ-mercaptopropyltrimethoxysilane-modified basic magnesium sulfate whisker, wherein the mass proportion of γ-mercaptopropyltrimethoxysilane is 1%.

[0026] Preferably, in step S2, the coupling agent is composed of vinyl triethoxysilane, γ-mercaptopropyl trimethoxysilane and γ-glycidyloxypropyl trimethoxysilane in a mass ratio of 3:4:3.

[0027] By adopting the above technical scheme, the role of these three silane coupling agents in this application is to improve the heat resistance stability, acid resistance and electrical insulation performance of azo pigments. The synergistic effect between vinyl triethoxysilane, γ-mercaptopropyl trimethoxysilane and γ-glycidyl ether oxypropyl trimethoxysilane is mainly reflected in the following aspects: Complementarity: These three silane coupling agents each have different functional characteristics. Through reasonable proportioning, they can achieve complementary advantages and jointly improve the comprehensive performance of azo pigments. Synergistic effect: When these three silane coupling agents act on azo pigments together, a synergistic effect may occur between them, making the performance improvement of azo pigments more significant. Stability: These three silane coupling agents have good dispersibility and compatibility in azo pigments, which is conducive to forming a stable bonding layer, thereby improving the stability of azo pigments.

[0028] Preferably, in step S3, the surfactant is at least one of polyquaternium-7, polyquaternium-39 and polyvinyl pyrrolidone.

[0029] Preferably, the surfactant is composed of polyquaternium-7, polyquaternium-39 and polyvinyl pyrrolidone in a mass fraction ratio of 2:3:5.

[0030] By adopting the above technical scheme, the role of surfactants in the preparation process of azo pigments is multifaceted. They effectively prevent the aggregation of azo pigment particles through steric hindrance and electrostatic stabilization, thereby improving their high diffusivity and fluidity. Polyquaternium-7: This is a cationic surfactant with good antibacterial and antistatic properties. In the preparation of azo pigments, polyquaternium-7 can combine with negatively charged azo pigment particles through electrostatic attraction to improve the stability of pigment particles and reduce particle aggregation caused by static electricity. Polyquaternium-39: This is also a cationic surfactant with good conditioning and antistatic properties. It can interact with the negative charge on the surface of azo pigment particles to form a stable colloidal system, thereby improving the dispersion and uniformity of the pigment. Polyvinylpyrrolidone: It is a non-ionic surfactant with good solubility and film-forming properties. In the preparation of azo pigments, PVP can be used as a dispersant and stabilizer. It can wrap around the pigment particles to form a protective layer to prevent particle aggregation and increase the gloss and fluidity of the pigment. When these three surfactants are used in combination, their synergistic effect can further enhance the performance of azo pigments. For example, polyquaternium-7 and polyquaternium-39 can form more stable complexes through the interaction of positive and negative charges, while PVP can provide additional steric hindrance and lubrication, making the entire system more stable and smooth. This combination improves the dispersibility and fluidity of azo pigments.

[0031] In the second aspect, the present application provides a highly diffusible environmentally friendly azo pigment, which adopts the following technical solution:

[0032] As a general technical concept, the present application also provides a high-diffusion environmentally friendly azo pigment prepared by the above-mentioned method for preparing a high-diffusion environmentally friendly azo pigment.

[0033] In summary, the beneficial technical effects of this application are:

[0034] 1. Improve the heat resistance, acid resistance and electrical insulation performance of azo pigments: By introducing modified mica powder and utilizing the organic film layer grafted on its surface, the hydrophilicity is changed to hydrophobicity, which not only improves the heat resistance and stability of azo pigments, but also enhances the acid and water resistance.

[0035] 2. Enhance thermal stability and flame retardant effect: Introduce silane-modified basic magnesium sulfate whiskers. This material can decompose to generate water vapor at high temperature, dilute the surrounding oxygen concentration and absorb heat, thereby effectively reducing the ambient temperature and improving the thermal stability and flame retardant ability of azo pigments.

[0036] 3. Improve tinting power and fluidity: The use of Ca and Sr ions for co-lake treatment significantly improves the tinting power and fluidity of azo pigments, making the pigments more suitable for various applications.

[0037] 4. Improve high diffusivity and fluidity: By adding surfactants, the aggregation of azo pigment particles is effectively prevented by utilizing steric hindrance and electrostatic stabilization, thereby improving the high diffusivity and fluidity of the pigment.

[0038] 5. Improved comprehensive performance: The azo pigments prepared by this method not only have high gloss and tinting strength, but also show excellent performance in terms of heat resistance, fluidity, water resistance, etc., making them more widely applicable and better performing in practical applications. DETAILED DESCRIPTION

[0039] Below in conjunction with embodiment, the embodiment of the present application is described in detail, but those skilled in the art will appreciate that the following examples are only used to illustrate the application, and should not be considered as limiting the scope of the application.Unindicated specific conditions in the embodiment, according to the condition of normal condition or manufacturer's suggestion, carry out.Reagents therefor or instrument are not indicated manufacturer, are the conventional products that can be obtained by commercially available purchase, and polyquaternium salt-7 and polyquaternium salt-39 are purchased from Lubrizol Corporation.

[0040] Preparation Example 1 Preparation of modified mica powder

[0041] The preparation method of modified mica powder comprises the following steps:

[0042] S41. According to the mass fraction, 10 kg of mica powder with a particle size of 1 micron was placed in a muffle furnace, the temperature was increased to 450° C., and calcined for 1.5 hours. After the calcination, it was added to 30 kg of a sulfuric acid solution with a mass concentration of 35%, ultrasonically stirred for 55 minutes, and allowed to stand for precipitation. The precipitate was washed with deionized water until it was neutral to obtain hydroxylated mica powder;

[0043] S42, according to the mass fractions, 0.8 kg of vinyl triethoxysilane was mixed with 50 kg of ethanol and 40 kg of water, and stirred evenly to obtain a mixture A;

[0044] S43, adding hydroxylated mica powder to mixture A, then heating to 40°C, stirring at 200 r / min for 150 min, and finally filtering, washing, drying at 85°C, and grinding to obtain modified mica powder.

[0045] Example 1

[0046] A method for preparing a highly diffusible environmentally friendly azo pigment comprises the following steps:

[0047] S1. The preparation of diazo liquid comprises the following steps, calculated by weight:

[0048] S11, in a diazo liquid reactor, 100 g of 2-chloro-4-aminotoluene-5-sulfonic acid, 40 g of 23% ammonia water, and 1300 g of water were mixed evenly, and after the 2-chloro-4-aminotoluene-5-sulfonic acid was completely dissolved, a mixed solution A was obtained;

[0049] S12, add 120g of 35% hydrochloric acid to the mixed solution A, mix well, add ice cubes to cool to 5°C, add 105g of 33% sodium nitrite aqueous solution at a rate of 6g / min, mix well, and keep for 60min to obtain a diazo solution;

[0050] S2, the preparation of the coupling solution, by weight, comprises the following steps:

[0051] 90g of 2-hydroxy-3-naphthoic acid, 120g of sodium hydroxide with a mass concentration of 24%, and 1500g of water are mixed evenly, and then 13g of a functional additive and 1g of a coupling agent are added, and the mixture is evenly mixed to obtain a coupling liquid; wherein the functional additive is prepared by mixing modified mica powder and γ-mercaptopropyltrimethoxysilane-modified basic magnesium sulfate whisker (γ-mercaptopropyltrimethoxysilane has a mass proportion of 1%) in a mass proportion of 2:1; the coupling agent is composed of vinyltriethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a mass proportion of 3:4:3;

[0052] S3, coupling reaction, calculated by mass fraction, comprises the following steps:

[0053] S31, in the coupling compound dissolving kettle, add diazo liquid, coupling liquid and 4g surfactant, mix and react, control the pH of the reaction end point to be 8.5, and obtain a coupling product; wherein the surfactant is polyquaternium-7;

[0054] S32. Add 280 g of 23% strontium chloride aqueous solution to the coupling product, stir for 90 minutes, heat to 80°C and further stir for 50 minutes, then add 30 g of 15% calcium carbonate and stir for 40 minutes, filter, wash with water, dry at 110°C for 24 hours and crush to obtain a highly diffuse environmentally friendly azo pigment.

[0055] Example 2

[0056] A method for preparing a highly diffusible environmentally friendly azo pigment comprises the following steps:

[0057] S1. The preparation of diazo liquid comprises the following steps, calculated by weight:

[0058] S11, in a diazo liquid reactor, 120 g of 2-chloro-4-aminotoluene-5-sulfonic acid, 50 g of 23% ammonia water, and 1500 g of water were mixed evenly, and after the 2-chloro-4-aminotoluene-5-sulfonic acid was completely dissolved, a mixed solution A was obtained;

[0059] S12, add 140g of 35% hydrochloric acid to the mixed solution A, mix well, add ice cubes to cool to 0°C, add 20g of 33% sodium nitrite aqueous solution at a rate of 7g / min, mix well, and keep for 70min to obtain a diazo solution;

[0060] S2, the preparation of the coupling solution, by weight, comprises the following steps:

[0061] 95g of 2-hydroxy-3-naphthoic acid, 130g of sodium hydroxide with a mass concentration of 24%, and 1700g of water are mixed evenly, and then 15g of a functional additive and 2g of a coupling agent are added, and the mixture is evenly mixed to obtain a coupling liquid; wherein the functional additive is prepared by mixing modified mica powder and γ-mercaptopropyltrimethoxysilane-modified basic magnesium sulfate whisker (γ-mercaptopropyltrimethoxysilane has a mass proportion of 1%) in a mass proportion of 2:1; the coupling agent is composed of vinyltriethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a mass proportion of 3:4:3;

[0062] S3, coupling reaction, calculated by mass fraction, comprises the following steps:

[0063] S31, in the coupling dissolving kettle, add diazo liquid, coupling liquid and 5g surfactant, mix and react, control the pH of the reaction end point to be 9.5, and obtain a coupling product; wherein the surfactant is polyquaternium-39;

[0064] S32. Add 310 g of 23% strontium chloride aqueous solution to the coupling product, stir for 120 minutes, heat to 80°C and stir for 60 minutes, then add 35 g of 15% calcium carbonate and stir for 50 minutes, filter, wash with water, dry at 110°C for 24 hours and crush to obtain a highly diffuse environmentally friendly azo pigment.

[0065] Example 3

[0066] A method for preparing a highly diffusible environmentally friendly azo pigment comprises the following steps:

[0067] S1. The preparation of diazo liquid comprises the following steps, calculated by weight:

[0068] S11, in a diazo liquid reactor, 110 g of 2-chloro-4-aminotoluene-5-sulfonic acid, 46 g of 23% ammonia water, and 1420 g of water were mixed evenly, and after the 2-chloro-4-aminotoluene-5-sulfonic acid was completely dissolved, a mixed solution A was obtained;

[0069] S12, add 131g of 35% hydrochloric acid to the mixed solution A, mix well, add ice cubes to cool to 3°C, add 112g of 33% sodium nitrite aqueous solution at a rate of 6.5g / min, mix well, and keep for 65min to obtain a diazo solution;

[0070] S2, the preparation of the coupling solution, by weight, comprises the following steps:

[0071] 93g of 2-hydroxy-3-naphthoic acid, 126g of sodium hydroxide with a mass concentration of 24%, and 1600g of water are mixed evenly, and then 14g of a functional additive and 1.5g of a coupling agent are added, and the mixture is evenly mixed to obtain a coupling liquid; wherein the functional additive is prepared by mixing modified mica powder and γ-mercaptopropyltrimethoxysilane-modified basic magnesium sulfate whisker (γ-mercaptopropyltrimethoxysilane has a mass proportion of 1%) in a mass proportion of 2:1; the coupling agent is composed of vinyltriethoxysilane, γ-mercaptopropyltrimethoxysilane and γ-glycidyloxypropyltrimethoxysilane in a mass proportion of 3:4:3;

[0072] S3, coupling reaction, calculated by mass fraction, comprises the following steps:

[0073] S31, in the coupling dissolving kettle, add diazo liquid, coupling liquid and 4.5g surfactant, mix and react, control the pH of the reaction end point to be 9, and obtain a coupling product; wherein the surfactant is polyvinyl pyrrolidone;

[0074] S32. Add 295 g of 23% strontium chloride aqueous solution to the coupling product, stir for 108 minutes, heat to 80°C and further stir for 54 minutes, then add 33 g of 15% calcium carbonate and stir for 45 minutes, filter, wash with water, dry at 110°C for 24 hours and crush to obtain a highly diffuse environmentally friendly azo pigment.

[0075] Example 4

[0076] The method is the same as Example 3, except that in step S31, the surfactant is composed of polyquaternium-7, polyquaternium-39 and polyvinyl pyrrolidone in a mass fraction ratio of 2:3:5.

[0077] Example 5

[0078] The same as Example 3, except that: in step S31, the surfactant is polyquaternium-7.

[0079] Example 6

[0080] The same as Example 3, except that: in step S31, the surfactant is polyquaternium-39.

[0081] Comparative Example 1

[0082] The same as Example 4, the difference is that: in step S2, the functional additive is modified mica powder.

[0083] Comparative Example 2

[0084] The same as Example 4, the difference is that: in step S2, the functional auxiliary agent is γ-mercaptopropyltrimethoxysilane modified basic magnesium sulfate whisker (γ-mercaptopropyltrimethoxysilane accounts for 1% by mass).

[0085] Comparative Example 3

[0086] The same as Example 4, the difference is that: in step S2, the functional additive is prepared by mixing mica powder with a particle size of 1 micron and basic magnesium sulfate whiskers in a mass ratio of 2:1.

[0087] Comparative Example 4

[0088] The same as Example 4, the difference is that: in step S2, the coupling agent is vinyl triethoxy silane.

[0089] Comparative Example 5

[0090] The same as Example 4, the difference is that: in step S2, the coupling agent is γ-mercaptopropyltrimethoxysilane.

[0091] Comparative Example 6

[0092] The same as Example 4, the difference is that: in step S2, the coupling agent is γ-glycidyloxypropyltrimethoxysilane.

[0093] Comparative Example 7

[0094] The same as Example 4, except that in step S32, the coupling product is filtered, washed with water, dried at 110° C. for 24 h and crushed to obtain a highly diffusible environmentally friendly azo pigment.

[0095] Performance Testing

[0096] The high diffusion environmentally friendly azo pigments prepared in Examples 1 to 6 and Comparative Examples 1 to 7 were sampled and the corresponding numbered color pastes were prepared: 30 g of the high diffusion environmentally friendly azo pigment was evenly mixed with 70 g of deionized water, and after ultrasonic stirring for 40 minutes, the following performance tests were performed. The test results are shown in Table 1;

[0097] Storage stability test: by visual inspection, the color pastes prepared from the high-diffusion environmentally friendly azo pigments prepared in Examples 1 to 6 and Comparative Examples 1 to 7 were observed after being sealed and placed at 60° C. for 60 days, 90 days, and 120 days to observe whether there was any obvious precipitation of pigment particles, flocculation, and other poor storage stability. The results were recorded in Table 1, where “√” indicates no abnormality and “×” indicates the presence of obvious precipitation of pigment particles, flocculation, and other poor storage stability;

[0098] Relative tinting strength test: The test was conducted by the method specified in Appendix B of the chemical industry standard "HG / T 4786-2014 Latex Color Paste", with the high diffusion environmentally friendly azo pigment color paste prepared in specific Example 4 as the standard color paste, and the relative tinting strength of the color pastes prepared in other examples and comparative examples was tested.

[0099] Fluidity test: The color pastes prepared from the high-diffusion environmentally friendly azo pigments obtained in Examples 1 to 6 and Comparative Examples 1 to 7 were dropped onto a glass plate perpendicular to the ground, and the length of flow within 5 minutes was recorded as fluidity.

[0100] Glossiness: The color paste prepared from the high-diffusion environmentally friendly azo pigments obtained in Examples 1 to 6 and Comparative Examples 1 to 7 was coated on a glass plate, the thickness of the pigment layer was controlled to be 20-25 μm, and the glossiness was tested after drying.

[0101] Table 1 Performance test

[0102]

[0103] Analyzing the data in Table 1, we can see that:

[0104] 1) The highly diffusible environmentally friendly azo pigments prepared in Examples 1 to 6 have excellent properties such as excellent gloss, tinting strength, heat resistance and fluidity.

[0105] 2) The performance comparison analysis of the high diffusion environmentally friendly azo pigment obtained in combination with Example 4 and Example 3, Example 5-Example 6 shows that the surfactant is composed of polyquaternium salt-7, polyquaternium salt-39 and polyvinyl pyrrolidone with a mass fraction ratio of 2:3:5, and the synergistic effect between them is utilized to effectively prevent the aggregation between the azo pigment particles through steric hindrance and electrostatic stabilization, thereby improving its high diffusion and fluidity. Make the whole system more stable and smooth. Such a combination improves the dispersibility and fluidity of the azo pigment.

[0106] 2) The performance comparison analysis of the high diffusion environmentally friendly azo pigments prepared in combination with Example 4 and Comparative Examples 1-2 shows that the use of functional additives prepared by mixing modified mica powder and silane-modified basic magnesium sulfate whiskers in a mass fraction of 2:1 can further improve the heat stability, acid resistance and electrical insulation performance of the azo pigment by utilizing the synergistic effect between them; at the same time, the adhesion, hardness and wear resistance of the pigment can also be improved. This makes the prepared azo pigment have excellent properties such as higher gloss, tinting power, heat resistance and fluidity.

[0107] 3) The performance comparison analysis of the high-diffusion environmentally friendly azo pigments prepared in Example 4 and Comparative Examples 4 to Comparative Examples 6 shows that the coupling agent is composed of vinyl triethoxysilane, γ-mercaptopropyl trimethoxysilane and γ-glycidyloxypropyl trimethoxysilane in a mass ratio of 3:4:3. By utilizing the synergistic effect between them, the dispersibility and compatibility in the azo pigment are further improved, which is conducive to the formation of a stable bonding layer, thereby improving the stability and overall performance of the azo pigment.

[0108] 4) The comparative analysis of the performance of the highly diffusible environmentally friendly azo pigments obtained in Example 4 and Comparative Example 7 shows that the azo pigments obtained by co-laked with Ca and Sr ions significantly improve the tinting power and fluidity of the azo pigments.

[0109] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation modes of the present invention can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the present application.

Claims

1. A method for preparing a highly diffusible environmentally friendly azo pigment, characterized in that: The following steps are involved: S1. The preparation of diazo liquid comprises the following steps, calculated by weight: S11, in a diazo liquid reactor, 100-120 parts by mass of 2-chloro-4-aminotoluene-5-sulfonic acid, 40-50 parts by mass of 23% ammonia water, and 1300-1500 parts by mass of water are mixed evenly, and after the 2-chloro-4-aminotoluene-5-sulfonic acid is completely dissolved, a mixed solution A is obtained; S12, adding 120-140 parts by mass of 35% hydrochloric acid to the mixed solution A, mixing well, adding ice cubes to cool to 0-5°C, adding 105-120 parts by mass of 33% sodium nitrite aqueous solution, mixing well, and keeping for 60-70 minutes to obtain a diazo solution; S2, the preparation of the coupling solution, by weight, comprises the following steps: 90-95 parts by weight of 2-hydroxy-3-naphthoic acid, 120-130 parts by weight of sodium hydroxide having a mass concentration of 24%, and 1500-1700 parts by weight of water are mixed uniformly, and then 13-15 parts by weight of a functional additive and 1-2 parts of a coupling agent are added, and the mixture is mixed uniformly to obtain a coupling liquid; S3, coupling reaction, calculated by mass fraction, comprises the following steps: S31, adding diazo liquid, coupling liquid and 4-5 parts of surfactant into the coupling compound dissolving kettle, mixing and reacting, controlling the pH at the reaction end point to be 8.5-9.5, to obtain a coupling product; S32, adding 280-310 parts by mass of a 23% aqueous strontium chloride solution to the coupling product, stirring for 90-120 minutes, heating to 80°C and further stirring for 50-60 minutes, adding 30-35 parts by mass of a 15% calcium carbonate and stirring for 40-50 minutes, filtering, washing, drying at 110°C for 24 hours and crushing to obtain a highly diffused environmentally friendly azo pigment; In step S12, the sodium nitrite aqueous solution is added at a rate of 6-7 parts by mass / min; In step S2, the functional additive is prepared by mixing modified mica powder and silane-modified basic magnesium sulfate whisker in a mass ratio of 2:1; The preparation method of the modified mica powder comprises the following steps: S41. According to the mass fraction, 10 parts of mica powder with a particle size of 1 micron are placed in a muffle furnace, the temperature is increased to 400-500° C., and calcined for 1-2 hours. After the calcination, it is added to 30 parts of a sulfuric acid solution with a mass concentration of 35%, ultrasonically stirred for 50-60 minutes, and allowed to stand for precipitation. The precipitate is washed with deionized water until it is neutral to obtain hydroxylated mica powder; S42, according to the weight ratio, 0.8 parts of vinyl triethoxysilane, 50 parts of ethanol and 40 parts of water were mixed and stirred to obtain a mixture A; S43, adding hydroxylated mica powder to mixture A, then heating to 40°C, stirring at a speed of 200 r / min for 150 min, and finally filtering, washing, drying at 85°C, and grinding to obtain modified mica powder; The silane-modified basic magnesium sulfate whisker is a γ-mercaptopropyltrimethoxysilane-modified basic magnesium sulfate whisker, wherein the mass proportion of γ-mercaptopropyltrimethoxysilane is 1%; In step S2, the coupling agent is composed of vinyl triethoxysilane, γ-mercaptopropyl trimethoxysilane and γ-glycidyloxypropyl trimethoxysilane in a mass ratio of 3:4:3; The surfactant is composed of polyquaternium-7, polyquaternium-39 and polyvinyl pyrrolidone in a mass fraction ratio of 2:3:

5.

2. A highly diffusible environmentally friendly azo pigment, characterized in that: The high-diffusion environmentally friendly azo pigment is prepared by the preparation method of claim 1.

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