Preparation method of epoxy resin coated ultramarine pigment microcapsule

Abstract

The invention discloses a preparation method of epoxy resin coated ultramarine pigment microcapsules, and belongs to the technical field of ultramarine pigments. The preparation method specifically comprises the following steps: S1, weighing an epoxy monomer, a curing agent, a reactive diluent and a catalyst according to a certain weight, and uniformly stirring and mixing; s2, adding the mixed solution prepared in S1 into the ultramarine pigment in a spraying form, and heating for curing reaction; and S3, heating the pre-product prepared in S2, and continuously keeping the temperature for a certain time to obtain the epoxy resin coated ultramarine pigment microcapsule. The preparation method of the epoxy resin coated ultramarine pigment microcapsule has the advantages that the preparation process is simple, no solvent is adopted, no harmful by-product is generated, and the prepared ultramarine microcapsule pigment has the advantages of high acid resistance, high tinting strength and good compatibility with a matrix; the method has potential application in the fields of cultural relic repair, art painting, plastic papermaking and the like.

Description

Technical Field

[0001] The invention relates to the technical field of ultramarine pigments, and in particular to a method for preparing ultramarine pigment microcapsules coated with epoxy resin. Background Art

[0002] Ultramarine is a blue inorganic pigment that has become one of the preferred pigments in the art and industrial fields due to its high color saturation and excellent covering power. In the art field, ultramarine pigments are often used in oil paintings and watercolors due to their superior light fastness and color stability; in industrial applications, ultramarine pigments are not only widely used in automotive coatings to provide long-lasting and weather-resistant color effects, but also in outdoor architectural coatings; in addition, high-quality ultramarine pigments are also used in the manufacture of printing inks and plastic products.

[0003] Although Ultramarine Blue has many advantages, its chemical structure is easily corroded under acidic conditions, resulting in color changes or quality degradation. This disadvantage limits its application in certain special scenarios, such as industrial environments with frequent or long-term exposure to acidic environments. Therefore, improving the acid resistance of Ultramarine Blue under these conditions is of great significance for expanding its application in a wider range of fields.

[0004] Microencapsulation technology is an effective way to protect pigments. By encapsulating ultramarine pigments in tiny capsules, it can effectively block direct contact between the pigment and environmental factors without affecting the color performance of the pigment itself. This encapsulation method not only improves the protection effect of the pigment, but also maintains the original color and gloss of the pigment.

[0005] In order to solve the technical problem of insufficient acid resistance of ultramarine pigment, the widely used technology is to modify ultramarine pigment through silicon-containing coating process. This method provides certain acid resistance protection by chemically depositing silicon-containing coating, such as silicon dioxide, on the surface of the pigment, but a large amount of silicon-containing wastewater will be generated during the deposition process. Improper treatment of these wastewaters may cause environmental pollution and require additional treatment measures to ensure that they meet discharge standards. Especially in large-scale industrial production, the cost of wastewater treatment and environmental pressure have gradually emerged, becoming one of the key factors affecting the sustainable development of the process. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing epoxy resin-coated ultramarine pigment microcapsules, using epoxy resin as a surface coating to solvent-free coat and modify the ultramarine pigment, so that the prepared ultramarine pigment microcapsules have good acid resistance and tinting power, thereby solving the problems of poor acid resistance of ultramarine pigments mentioned in the above background technology and the generation of wastewater and environmental pollution in the existing silicon-containing coating process.

[0007] To achieve the above object, the present invention provides a method for preparing epoxy resin-coated ultramarine pigment microcapsules, the specific steps of which include:

[0008] S1, taking epoxy monomer, curing agent, active diluent and catalyst, stirring and mixing to obtain mixture A;

[0009] S2, adding ultramarine pigment into a high-speed mixer, and after heating, adding mixture A into the ultramarine pigment in batches in the form of spray;

[0010] S3. After the addition is completed, the temperature is raised to perform a curing reaction. After the reaction is completed, the heating is turned off, and the material is discharged after natural cooling to obtain an ultramarine pigment coated with epoxy resin.

[0011] Preferably, the amounts of ultramarine pigment, epoxy monomer, curing agent, reactive diluent and catalyst used are as follows by weight: 100 parts of ultramarine pigment, 5-20 parts of epoxy monomer, 1-10 parts of curing agent, 0.5-10 parts of reactive diluent and 0.05-0.5 parts of catalyst.

[0012] Preferably, the epoxy monomer is one of bisphenol A glycidyl ether, glycidyl phenyl ether, glycidyl cresol ether, bisphenol F glycidyl ether, glycidyl alkyl ether, glycidyl methacrylate, and glycidyl adipate.

[0013] Preferably, the active diluent is at least one of phenyl glycidyl ether, butyl glycidyl ether, C12-C14 glycidyl ether, glycidyl acetate, 1,4-butanediol glycidyl ether, neopentyl glycol glycidyl ether, glycidyl aniline, and glycidyl toluidine.

[0014] Preferably, the curing agent is at least one of diaminodiphenylmethane, diaminodiphenyl sulfone, m-phenylenediamine, ethylenediamine, triethylenetetramine, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and maleic anhydride.

[0015] Preferably, the catalyst is at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, tributyl phosphate, lithium hexafluorophosphate, cobalt acetate, and zinc chromate.

[0016] Preferably, in step S2, the temperature is raised to 100-120°C.

[0017] Preferably, the curing temperature of step S3 is 80-170° C., and the curing time is 2-10 hours.

[0018] The present invention uses epoxy resin as a surface coating, atomizes epoxy monomer, curing agent, diluent, and catalyst, and then dry-mixes them with ultramarine pigment to prepare ultramarine pigment microcapsules. Compared with using a silicon-containing coating to coat ultramarine pigment, in the ultramarine pigment microcapsules obtained by this method, epoxy resin is a microcapsule capsule material, and ultramarine pigment is a microcapsule core material. The prepared ultramarine pigment microcapsules have better acid resistance and good tinting power, are suitable for more demanding use environments, and avoid environmental and safety hazards caused by processing waste solvents. While improving the performance of ultramarine pigment, this method also improves the sustainability of the production process.

[0019] Therefore, the present invention provides a method for preparing epoxy resin-coated ultramarine pigment microcapsules, which has the following beneficial effects:

[0020] (1) Improved acid resistance of ultramarine blue pigment: The epoxy resin solvent-free coating modification technology effectively improves the tolerance of ultramarine blue pigment in acidic environment, overcomes the problem that traditional ultramarine blue pigment is easily corroded by acid, and enhances its application potential in harsh environments;

[0021] (2) Maintain good tinting strength: Epoxy resin coating not only improves the acid resistance of ultramarine pigment, but also maintains its excellent tinting strength and color performance, ensuring that it can still provide stable color effects in different application scenarios;

[0022] (3) Solvent-free and environmentally friendly process: This preparation process does not use solvents, but uses active diluents instead of water or organic solvents. Compared with the traditional silicon-containing coating process, it reduces the discharge of silicon-containing waste liquid, avoids the environmental burden and safety hazards of treating waste solvents, improves the environmental friendliness of the process, and effectively reduces the potential risks in the production process.

[0023] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION

[0024] The present invention provides a method for preparing epoxy resin-coated ultramarine pigment microcapsules, which comprises the following steps:

[0025] S1, weighing a certain weight of epoxy monomer, curing agent, reactive diluent and catalyst, stirring and mixing to obtain a mixture A;

[0026] S2, adding the mixture A to the ultramarine pigment in the form of a spray, and heating to perform a curing reaction;

[0027] S3, mixing the products prepared in S2 and continuing to keep warm for a certain period of time to obtain epoxy resin-coated ultramarine pigment microcapsules.

[0028] In the present invention, a high-speed mixer is used to stir and mix epoxy monomer, curing agent, reactive diluent and catalyst at room temperature to obtain a liquid mixture, wherein the amounts of ultramarine pigment, epoxy monomer, curing agent, reactive diluent and catalyst are as follows by weight: 100 parts of ultramarine pigment, 5-20 parts of epoxy monomer, 1-10 parts of curing agent, 0.5-10 parts of reactive diluent and 0.05-0.5 parts of catalyst.

[0029] In the present invention, the active diluent is used to replace water or organic solvent in the traditional coating process, which can effectively reduce the viscosity of the epoxy resin system, improve its fluidity, facilitate spraying operation and uniform coating of ultramarine pigment. In addition, the active diluent can also adjust the flexibility and durability of the coating layer, and improve the stability and weather resistance of the ultramarine pigment microcapsules in different environments. Among them, the active diluent is at least one of phenyl glycidyl ether, butyl glycidyl ether, C12-C14 glycidyl ether, glycidyl acetate, 1,4-butanediol glycidyl ether, neopentyl glycol glycidyl ether, glycidyl aniline, and glycidyl toluidine.

[0030] In the present invention, the curing temperature of the epoxy-coated ultramarine pigment is 80-170° C., and the curing time is 2-10 hours; further, the curing temperature is 120-150° C., and the curing time is 6-8 hours.

[0031] In the present invention, the epoxy resin is coated on the surface of the ultramarine pigment to isolate the ultramarine pigment from contact with the acidic environment and protect the internal pigment. The epoxy monomer is one of bisphenol A type glycidyl ether, glycidyl phenyl ether, glycidyl cresol ether, bisphenol F type glycidyl ether, glycidyl alkyl ether, glycidyl methacrylate, and glycidyl adipate.

[0032] In the present invention, the curing agent is at least one of diaminodiphenylmethane, diaminodiphenyl sulfone, m-phenylenediamine, ethylenediamine, triethylenetetramine, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and maleic anhydride.

[0033] In the present invention, the catalyst is at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, tributyl phosphate, lithium hexafluorophosphate, cobalt acetate, and zinc chromate.

[0034] The present invention is further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Any other changes, modifications, substitutions, combinations, simplifications made without violating the spirit and principle of the present invention should all be equivalent replacement methods and are included in the protection scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application, and all belong to the scope of protection of the present invention.

[0035] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0036] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0037] Unless otherwise specified in the present invention, the reagents, instruments, and equipment used are those commonly used by technicians in this field.

[0038] In the following examples, ultramarine pigment is a commercial product with a brand number of 463 from Shandong Tianlan Pigment Company; bisphenol A glycidyl ether is a commercial product with a brand number of E44 from Sinopec Baling Petrochemical Company; bisphenol F glycidyl ether is a commercial product with a brand number of NPEF170 from Nan Ya Plastics Company; glycidyl phenyl ether, diaminodiphenylmethane, diaminodiphenyl sulfone, methylimidazole, tributyl phosphate, and cobalt acetate were purchased from Shanghai Aladdin Biotechnology Co., Ltd.

[0039] In the following examples and comparative examples, the loading rate of epoxy resin on ultramarine pigment was determined by the mass change before and after coating:

[0040] Load factor = (W2-W1) / W1×100%;

[0041] W1 – the quality of ultramarine pigment before modification;

[0042] W2——the quality of ultramarine pigment after modification;

[0043] Acid resistance test: Referring to GB / T5211.5-2008 standard, 0.5g sample was mixed with 20mL of 10wt% hydrochloric acid solution and then shaken vigorously for 5 minutes. After filtering, rinsing and drying the pigment, the color change was compared with the gray scale card to evaluate its acid resistance level. The acid resistance level is divided into 1-8, where level 1 means that the color of the pigment has completely faded, and level 8 means that there is no fading at all. The higher the level, the stronger the acid resistance of the pigment.

[0044] Tinting strength test: refer to GB / T5211.19-1988 standard, add 1% ultramarine pigment to the paint base, mix thoroughly to ensure uniform dispersion of the pigment. Apply the mixed paint evenly on the standard test plate and dry it. After drying, evaluate the tinting strength according to the standard colorimetric card. The tinting strength grade is determined by comparing the color intensity with the standard sample to obtain the corresponding grade.

[0045] Example 1

[0046] This embodiment provides a method for preparing epoxy resin-coated ultramarine pigment microcapsules, which specifically comprises the following steps:

[0047] S1. Weigh 100 g of bisphenol A glycidyl ether, 50 g of phenyl glycidyl ether, 40 g of diaminodiphenylmethane and 2 g of 2-methylimidazole and stir and mix them evenly;

[0048] S2. Add 1 kg of ultramarine powder to a 10 L high-speed mixer, raise the temperature to 100 °C and keep warm. Use an atomizer to add the mixed solution obtained in S1 to the high-speed mixer in four times in the form of mist, with an interval of 5 minutes between each addition.

[0049] S3. After the addition is completed, the high-speed mixer is heated to 120°C. After curing for 6 hours, the heating is turned off. The material is discharged after naturally cooling to room temperature and sealed for storage to obtain 1150 g of ultramarine pigment (MU-1) coated with epoxy resin, with a yield of 96%.

[0050] Example 2

[0051] This embodiment provides a method for preparing epoxy resin-coated ultramarine pigment microcapsules, which specifically comprises the following steps:

[0052] S1. Weigh 200 g of bisphenol A glycidyl ether, 100 g of glycidyl alkyl ether, 80 g of methyltetrahydrophthalic anhydride and 4 g of cobalt acetate and stir and mix them evenly;

[0053] S2, add 2kg of ultramarine powder to a 10L high-speed mixer, heat to 120℃ and keep warm, use an atomizer to add the mixture obtained in S1 into the high-speed mixer in 4 times in the form of mist, each time with an interval of 5 minutes;

[0054] S3. After the addition is completed, the high-speed mixer is heated to 150°C. After curing for 6 hours, the heating is turned off. The mixture is discharged after naturally cooling to room temperature and sealed for storage to obtain 2320 g of ultramarine pigment (MU-3) coated with epoxy resin, with a yield of 97%.

[0055] Example 3

[0056] This embodiment provides a method for preparing epoxy resin-coated ultramarine pigment microcapsules, which specifically comprises the following steps:

[0057] S1, weigh 200g of bisphenol F glycidyl ether, 50g of phenyl glycidyl ether, 80g of diaminodiphenyl sulfone and 4g of tributyl phosphate and stir and mix them evenly;

[0058] S2. Add 1 kg of ultramarine powder to a 10 L high-speed mixer, raise the temperature to 120°C and keep warm. Use an atomizer to add the mixed solution obtained in S1 to the high-speed mixer in four times in the form of mist, with an interval of 5 minutes between each time.

[0059] S3. After the addition is completed, the high-speed mixer is heated to 150°C. After curing for 8 hours, the heating is turned off. The material is discharged after naturally cooling to room temperature and sealed for storage to obtain 1250 g of ultramarine pigment (MU-2) coated with epoxy resin, with a yield of 94%.

[0060] In order to describe the acid resistance and tinting strength of the epoxy resin modified ultramarine pigment prepared in the present application, two groups of comparative examples are also provided.

[0061] Comparative Example 1

[0062] Unmodified Ultramarine Pigment.

[0063] Comparative Example 2

[0064] The preparation method of the ultramarine pigment coated with silica is as follows: 500g of ultramarine pigment and 5kg of deionized water are added to a 20L reactor, and the mixture is stirred for 15 minutes to form a uniform slurry. The pH value of the slurry is adjusted to 9.5 by adding 0.1M NaOH, and the mixture is heated to 90°C. Within 1 hour, 500mL of sodium silicate solution and 500mL of NH4Cl solution are added to the slurry at the same time. After the addition is completed, the reaction is continued for 3h, the mixture is cooled to room temperature, and the crude product is filtered to obtain the crude product, which is washed with ethanol water twice, washed with deionized water once, and then dried to obtain 596g of ultramarine pigment (SU-1) coated with silica, with a yield of 80%.

[0065] The products obtained in Examples 1-3 and Comparative Examples 1-2 were tested for particle size, loading rate, acid resistance and tinting strength. The test results are shown in Table 1.

[0066] Table 1

[0067]

[0068] It can be seen from the data in Table 1 that the particle size of the epoxy resin-coated ultramarine pigment in Examples 1-3 is slightly increased, and compared with the unmodified ultramarine pigment in Comparative Example 1 and the silica-coated ultramarine pigment in Comparative Example 2, the acid resistance and tinting power are significantly improved, and have potential application prospects.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing epoxy resin-coated ultramarine pigment microcapsules, characterized in that: The specific steps include: S1, taking epoxy monomer, curing agent, active diluent and catalyst, stirring and mixing to obtain mixture A; S2, adding ultramarine pigment into a high-speed mixer, and after heating, adding mixture A into the ultramarine pigment in batches in the form of spray; S3. After the addition is completed, the temperature is raised to perform a curing reaction. After the reaction is completed, the heating is turned off, and the material is discharged after natural cooling to obtain an ultramarine pigment coated with epoxy resin.

2. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: In terms of weight, the amount of ultramarine pigment, epoxy monomer, curing agent, reactive diluent and catalyst is as follows: 100 parts of ultramarine pigment, 5-20 parts of epoxy monomer, 1-10 parts of curing agent, 0.5-10 parts of reactive diluent and 0.05-0.5 parts of catalyst.

3. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: The epoxy monomer is one of bisphenol A type glycidyl ether, glycidyl phenyl ether, glycidyl cresol ether, bisphenol F type glycidyl ether, glycidyl alkyl ether, glycidyl methacrylate, and glycidyl adipate.

4. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: The active diluent is at least one of phenyl glycidyl ether, butyl glycidyl ether, C12-C14 glycidyl ether, glycidyl acetate, 1,4-butanediol glycidyl ether, neopentyl glycol glycidyl ether, glycidyl aniline and glycidyl toluidine.

5. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: The curing agent is at least one of diaminodiphenylmethane, diaminodiphenyl sulfone, m-phenylenediamine, ethylenediamine, triethylenetetramine, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride and maleic anhydride.

6. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: The catalyst is at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, tributyl phosphate, lithium hexafluorophosphate, cobalt acetate and zinc chromate.

7. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: In step S2, the temperature is raised to 100-120°C.

8. The method for preparing epoxy resin-coated ultramarine pigment microcapsules according to claim 1, characterized in that: The curing temperature of step S3 is 80-170° C., and the curing time is 2-10 hours.

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