Environment-friendly electric wave absorbing coating and preparation method thereof

Abstract

The invention relates to the technical field of wave absorbing materials, in particular to an environment-friendly electric wave absorbing coating which comprises the following components in parts by weight: 30-60 parts of styrene-acrylic emulsion, 20-60 parts of an electromagnetic wave absorbent, 0.5-5 parts of a coupling agent, 1-4 parts of a dispersing agent, 20-40 parts of a flame retardant and a certain amount of purified water. The invention further relates to a preparation method of the environment-friendly electric wave absorbing coating. According to the invention, toxic and harmful solvents are abandoned, so that the coating is more environment-friendly and safer, and the wave-absorbing performance is not obviously reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wave absorbing materials, and in particular to an environmentally friendly radio wave absorbing coating and a preparation method thereof. Background Art

[0002] Currently, absorbing materials are widely used in military, aviation, aerospace, communications, electromagnetic protection, and electromagnetic shielding. They absorb and attenuate electromagnetic waves that strike their surfaces, converting their energy into heat and dissipating it, or causing them to disappear due to interference. This effectively reduces electromagnetic wave reflection. Absorbent coatings, with their simple preparation, ease of use, and low cost, are an ideal solution for achieving this absorption function.

[0003] Existing radar-absorbing coatings are typically formulated with an absorbent, a base resin, a solvent, and additives for application to target surfaces. The absorbent is the primary component for absorbing electromagnetic waves and is the primary factor determining the coating's absorbing properties, directly impacting their overall performance. The base resin, also known as the film-forming substance, is the primary material that allows the coating to adhere firmly to the surface, forming a continuous film. It also serves as a bond between the absorbent and other components, determining the coating's physical and mechanical properties and environmental resistance. The solvent is primarily used to dissolve and disperse the base resin, adjust the coating's viscosity, and facilitate its preparation and application. Additives are primarily used to adjust the coating's appearance, such as surface smoothness, porosity, and spotting.

[0004] To ensure ease of preparation, dispersion, and application, traditional radar-absorbing coatings contain large amounts of organic solvents to dissolve the dispersed resin and absorbent. These solvents are mostly toxic, hazardous, and volatile, including benzene, ketones, and alcohols, such as toluene, xylene, cyclohexanone, butanone, methyl isobutyl ketone, and butanol. These organic solvents are highly toxic and potentially hazardous, with toluene and xylene, containing benzene rings, being particularly carcinogenic. These solvents evaporate and emit during the coating manufacturing, application, and curing processes, and the long-term release of residual solvents in the coating after curing poses a health and safety hazard to operators, pollutes the environment, and wastes significant resources and energy. Currently, the environmental pollution caused by these highly toxic and hazardous solvents is gaining increasing attention, and their use and discharge are increasingly subject to national environmental regulations. Therefore, the radar-absorbing coating industry must take measures to reduce the use of traditional toxic and hazardous solvents. Summary of the Invention

[0005] The purpose of the present invention is to provide an environmentally friendly radio wave absorbing coating and a preparation method thereof, so as to solve the toxic and harmful problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: An environment-friendly electromagnetic wave absorbing coating, which comprises the following components by weight: 30-60 parts of styrene-acrylic emulsion, 20-60 parts of electromagnetic absorber, 0.5-5 parts of coupling agent, 1-4 parts of dispersant, 20-40 parts of flame retardant, and a certain amount of pure water.

[0007] Preferably, the base material is mainly styrene-acrylic emulsion, with a solid content of 40-60%, and it is modified by silicification.

[0008] Preferably, the electromagnetic wave absorber includes but is not limited to conductive carbon materials, such as one or more of conductive carbon black, graphene, carbon fiber, single-walled / multi-walled carbon nanotubes, conductive silver powder, etc.

[0009] Preferably, the electromagnetic wave absorber also includes a magnetic loss electromagnetic wave absorber, which includes but is not limited to one or more of materials such as carbonyl iron, ferrite powder, silicon carbide, borosilicate aluminum, retinol Schiff base salt, etc.

[0010] Preferably, the coupling agent mainly includes silane coupling agents, and typical models are KH-550 and KH560.

[0011] Preferably, the typical model of the dispersant is mainly JR-H100.

[0012] Preferably, the flame retardant is mainly a compound of one or several of modified magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, melamine hydrobromide, etc.

[0013] Preferably, according to the ratio, after stirring evenly, an appropriate amount of pure water is added to control the viscosity of the coating, so that it can be better coated on the surface of the base material.

[0014] This application also provides a preparation method of the environment-friendly electromagnetic wave absorbing coating, which includes the following steps: Step S1: Weigh the electromagnetic wave absorber and the dispersant powder according to the ratio, and place them in a grinder for grinding to obtain mixture 1; Step S2: Use a high-speed stirrer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 5-10 min. Atomize the coupling agent and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder; Step S3: Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring barrel, and stir at 1200 r / min for 5-10 min to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir and mix at a high speed of 1300 r / min for 20-40 min; Step S4: Slowly add the flame retardant powder obtained after modification to the mixture obtained in Step 3. At the same time, appropriately add an appropriate amount of water to the blender according to the oil absorption value of the flame retardant to control the viscosity of the coating, and obtain wave-absorbing coatings with different viscosities.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Environmental protection: Since no organic solvents are used, these coatings do not release harmful volatile substances during production and application, thus reducing environmental pollution.

[0016] 2. Safety: Since they do not contain flammable or explosive organic solvents, they are safer to operate, and this safety is particularly important in enclosed environments or areas with poor ventilation.

[0017] 3. High solid content: The solid content of solvent-free coatings is very high, which means that more of the coating components will remain in the coating rather than being released into the atmosphere as volatile organic compounds.

[0018] 4. Fast curing: The reaction rate of solvent-free coatings is usually very fast, which means that the coating can reach full hardness in a very short time. This fast hardening characteristic also enables a significant increase in production efficiency.

[0019] 5. Excellent physical properties: Since they do not contain organic solvents, their coatings are denser, which can effectively block corrosive media such as water and oxygen from penetrating the coating and corroding the internal substances. At the same time, this denseness also helps to improve the wear resistance and corrosion resistance of the coating. Specific embodiments

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0021] An environment-friendly radio wave absorbing coating, which includes the following components by weight: 30-60 parts of styrene-acrylic emulsion, 20-60 parts of electromagnetic wave absorber, 0.5-5 parts of coupling agent, 1-4 parts of dispersant, 20-40 parts of flame retardant, and a certain amount of pure water.

[0022] The base material is mainly styrene-acrylic emulsion, with a solid content of 40-60%, and it is modified by silicification.

[0023] The electromagnetic wave absorber includes but is not limited to conductive carbon materials, such as one or more of conductive carbon black, graphene, carbon fiber, single-walled / multi-walled carbon nanotubes, conductive silver powder and other materials.

[0024] The electromagnetic wave absorber further includes a magnetic loss electromagnetic wave absorber, which includes but is not limited to one or more of materials such as carbonyl iron, ferrite powder, silicon carbide, aluminum borosilicate, and retinyl Schiff base salt.

[0025] The coupling agent mainly includes silane coupling agents, and typical models are KH-550 and KH560.

[0026] The typical model of the dispersant is mainly JR-H100.

[0027] The flame retardant is mainly a compound of one or several of modified magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, melamine hydrobromide, etc.

[0028] According to the ratio, after stirring evenly, an appropriate amount of pure water is added to control the viscosity of the coating, so that it can be better coated on the surface of the substrate. Specific implementation steps

[0029] 1. Weigh the electromagnetic wave absorber and the dispersant powder according to the ratio, and place them in a grinder for grinding to obtain mixture 1.

[0030] 2. Use a high-speed stirrer to rotate the flame retardant powder at a high speed of 1,359 r / min and stir for 5 - 10 minutes. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder.

[0031] 3. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1,200 r / min for 5 - 10 minutes to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir and mix at a high speed of 1,300 r / min for 20 - 40 minutes.

[0032] 4. Slowly add the flame retardant powder obtained after modification to the mixture obtained in step 3. At the same time, according to the oil absorption value of the flame retardant, appropriately add an appropriate amount of water to the mixer to control the viscosity of the coating, and obtain wave-absorbing coatings with different viscosities, which can be applied to various construction methods such as spraying, coating, and soaking.

[0033] 5. After the wave-absorbing coating is sprayed, coated, or soaked on the surface of the object, it can be naturally air-dried to obtain a wave-absorbing coating with stable wave-absorbing performance.

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Specific embodiments will be described below. In the detailed embodiments and comparative examples, the different parts of each production formula and process are mainly introduced, and the same process refers to the detailed steps in the invention content. Embodiment

[0035] An environment-friendly electromagnetic wave absorbing coating, by weight, comprises the following components: 30 parts of styrene-acrylic emulsion, 20 parts of electromagnetic wave absorber, 0.5 part of coupling agent, 1 part of dispersant, 20 parts of flame retardant, and a certain amount of pure water.

[0036] Among them, the coupling agent mainly includes silane coupling agent, and the model is KH-550; Among them, the dispersant model is JR-H100.

[0037] Mix the electromagnetic wave absorber and the dispersant powder, place it in a grinder for grinding to obtain mixture 1. Use a high-speed stirrer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 5 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, and stir at 1200 r / min for 5 min to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir at 1300 r / min for 20 min at high speed to obtain mixture 2. Slowly add the modified flame retardant powder to mixture 2 and stir slowly.

[0038] Comparative Example 1 An environment-friendly electromagnetic wave absorbing coating, by weight, comprises the following components: 30 parts of styrene-acrylic emulsion, 20 parts of electromagnetic wave absorber, 0.5 part of coupling agent, 1 part of solvent, 20 parts of flame retardant, and a certain amount of pure water.

[0039] Among them, the coupling agent mainly includes silane coupling agent, and the model is KH-550; Among them, the dispersant model is JR-H100.

[0040] Mix the electromagnetic wave absorber and the solvent, place it in a stirring tank, and stir at 1200 r / min for 5 min to obtain mixture 1. Use a high-speed stirrer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 5 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, and stir at 1200 r / min for 5 min to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir at 1300 r / min for 20 min at high speed to obtain mixture 2. Slowly add the modified flame retardant powder to mixture 2 and stir slowly. Example

[0041] An environment-friendly electromagnetic wave absorbing coating, by weight, comprises the following components: 40 parts of styrene-acrylic emulsion, 35 parts of electromagnetic wave absorber, 2 parts of coupling agent, 2 parts of dispersant, 25 parts of flame retardant, and a certain amount of pure water.

[0042] Among them, the coupling agent mainly includes silane coupling agent, and the model is KH-550; Among them, the dispersant model is JR-H100.

[0043] Mix the electromagnetic wave absorbing agent with the dispersant powder, place it in a grinder for grinding to obtain mixture 1. Use a high-speed mixer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 5 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1200 r / min for 5 min to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir at a high speed of 1300 r / min for 20 min to obtain mixture 2. Slowly add the modified flame retardant powder to mixture 2 and stir slowly.

[0044] Comparative Example 2 An environment-friendly radio wave absorbing coating includes the following components by weight: 40 parts of styrene-acrylic emulsion, 35 parts of electromagnetic wave absorber, 2 parts of coupling agent, 2 parts of solvent, 25 parts of flame retardant, and a certain amount of pure water.

[0045] Among them, the coupling agent mainly includes silane coupling agent, and the model is KH-550; Among them, the dispersant model is JR-H100.

[0046] Mix the electromagnetic wave absorbing agent with the solvent, place it in a stirring tank, stir at 1200 r / min for 5 min to obtain mixture 1. Use a high-speed mixer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 5 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1200 r / min for 5 min to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir at a high speed of 1300 r / min for 20 min to obtain mixture 2. Slowly add the modified flame retardant powder to mixture 2 and stir slowly. Example

[0047] An environment-friendly radio wave absorbing coating includes the following components by weight: 50 parts of styrene-acrylic emulsion, 50 parts of electromagnetic wave absorber, 3.5 parts of coupling agent, 3 parts of dispersant, 30 parts of flame retardant, and a certain amount of pure water.

[0048] Among them, the coupling agent mainly includes silane coupling agent, and the model is KH-560; Among them, the dispersant model is JR-H100.

[0049] Mix the electromagnetic wave absorber and the dispersant powder, place them in a grinder for grinding to obtain Mixture 1. Use a high-speed agitator to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 10 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1200 r / min for 10 min to effectively dilute the styrene-acrylic emulsion. Then add Mixture 1, use 1300 r / min, stir and mix at high speed for 30 min to obtain Mixture 2. Slowly add the modified flame retardant powder to Mixture 2 and stir slowly.

[0050] Comparative Example 3 An environment-friendly radio wave absorbing coating includes the following components by weight: 50 parts of styrene-acrylic emulsion, 50 parts of electromagnetic wave absorber, 3.5 parts of coupling agent, 3 parts of solvent, 30 parts of flame retardant, and a certain amount of pure water.

[0051] Among them, the coupling agent mainly includes a silane coupling agent with the model KH-560; Among them, the dispersant has the model JR-H100.

[0052] Mix the electromagnetic wave absorber and the solvent, place them in a stirring tank, stir at 1200 r / min for 10 min to obtain Mixture 1. Use a high-speed agitator to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 10 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1200 r / min for 10 min to effectively dilute the styrene-acrylic emulsion. Then add Mixture 1, use 1300 r / min, stir and mix at high speed for 30 min to obtain Mixture 2. Slowly add the modified flame retardant powder to Mixture 2 and stir slowly. Example

[0053] An environment-friendly radio wave absorbing coating includes the following components by weight: 60 parts of styrene-acrylic emulsion, 60 parts of electromagnetic wave absorber, 5 parts of coupling agent, 4 parts of dispersant, 40 parts of flame retardant, and a certain amount of pure water.

[0054] Among them, the coupling agent mainly includes a silane coupling agent with the model KH-560; Among them, the dispersant has the model JR-H100.

[0055] Mix the electromagnetic wave absorber and the dispersant powder, place them in a grinder and grind to obtain Mixture 1. Use a high-speed mixer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 10 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1200 r / min for 10 min to effectively dilute the styrene-acrylic emulsion. Then add Mixture 1, use 1300 r / min and stir at high speed for 40 min to obtain Mixture 2. Slowly add the flame retardant powder obtained after modification to Mixture 2 and stir slowly.

[0056] Comparative Example 4 An environment-friendly electromagnetic wave absorbing coating comprises the following components by weight: 60 parts of styrene-acrylic emulsion, 60 parts of electromagnetic wave absorber, 5 parts of coupling agent, 4 parts of solvent, 40 parts of flame retardant, and a certain amount of pure water.

[0057] Among them, the coupling agent mainly includes silane coupling agent, and the model is KH-560; Among them, the dispersant model is JR-H100.

[0058] Mix the electromagnetic wave absorber and the solvent, place them in a stirring tank, stir at 1200 r / min for 10 min to obtain Mixture 1. Use a high-speed mixer to rotate the flame retardant powder at a high speed of 1359 r / min and stir for 10 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder. Add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, stir at 1200 r / min for 10 min to effectively dilute the styrene-acrylic emulsion. Then add Mixture 1, use 1300 r / min and stir at high speed for 40 min to obtain Mixture 2. Slowly add the flame retardant powder obtained after modification to Mixture 2 and stir slowly. <*

[0059] According to the above specific embodiments, Examples 1-4 and Comparative Examples 1-4 are proposed, and the performance tests are carried out on the coatings prepared according to Examples 1-4 and Comparative Examples 1-4. The specific preparation parameters and performance results are shown in Table 1: Table 1 The ratio and performance table of Examples 1-4 and Comparative Examples 1-4.

[0060]

[0061] As can be seen from Table 1, after using the solvent in the comparative example, the measured toxic and harmful substances are significantly more than those in the examples, slightly higher than the safety standard, and there is no obvious difference in the wave absorption performance compared with the examples.

[0062] Test Example Coating Adhesion Test: According to ISO 2409 as the reference standard, the cross-cut method was used to test the adhesion of the coating. The coatings prepared in Examples 1-4 and Comparative Examples 1-4 were evenly applied on the soft bottom material with a uniform coating thickness of 60 μm. After the coating was completely dried, a sharp utility knife was used to draw several straight lines on the surface of the dried coating at the same angle and force with an appropriate spacing, penetrating the coating and reaching the material surface. Repeat the above operation and cut the coating again at a 90° angle to form a grid. Then, use a brush to remove the fine debris around the grid. Cut a 75-mm-long tape and stick it firmly on the grid, ensuring that the tape is in the same direction as any scratch and the center of the tape is within the grid. Place the tape parallel to the scribed lines in the middle of the grid, leaving at least 20 mm outside the grid for easy grasping by hand. Smooth the tape with fingers. Then, within 5 minutes after sticking the tape, hold one end of the tape and tear it off at a constant speed at a 60° angle within 0.5 - 1 s. Immediately observe the grid situation after tearing off the tape and compare it with the test result grading table in the standard to obtain the test result. The cross-cut test was repeated 3 times for each of Examples 1-4 and Comparative Examples 1-4. The adhesion test results are shown in Table 2: Table 2 Comparison Table of Cross-Cut Tests for Examples 1-4 and Comparative Examples 1-4

[0063]

[0064] As can be seen from Table 2, there is no significant difference in the adhesion of the coatings in Examples 1-4 and Comparative Examples 1-4, and all meet the standards.

[0065] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed within the present invention.

[0066] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An environment-friendly radio wave absorbing coating, characterized in that It includes the following components by weight parts: 30 - 60 parts of styrene-acrylic emulsion, 20 - 60 parts of electromagnetic wave absorber, 0.5 - 5 parts of coupling agent, 1 - 4 parts of dispersant, 20 - 40 parts of flame retardant, and a certain amount of pure water.

2. The environmentally friendly radio wave absorbing paint according to claim 1, characterized in that, The base material is mainly styrene-acrylic emulsion with a solid content of 40 - 60%, which has been silicified and modified.

3. The environmentally friendly radio wave absorbing paint according to claim 1, characterized in that, The electromagnetic wave absorber includes but is not limited to conductive carbon materials, such as one or more of conductive carbon black, graphene, carbon fiber, single-walled / multi-walled carbon nanotubes, conductive silver powder, etc.

4. The environmentally friendly radio wave absorbing paint according to claim 3, wherein, The electromagnetic wave absorber also includes a magnetic loss electromagnetic wave absorber, which includes but is not limited to one or more of materials such as carbonyl iron, ferrite powder, silicon carbide, borosilicate aluminum, retinol Schiff base salt, etc.

5. An environment-friendly radio wave absorbing paint according to claim 1, characterized in that, The coupling agent mainly includes silane coupling agents, with typical models KH-550 and KH560.

6. The environmentally friendly radio wave absorbing paint according to claim 1, wherein The typical model of the dispersant is mainly JR-H100.

7. An environment-friendly radio wave absorbing paint according to claim 1, characterized in that, The flame retardant mainly is a compound of one or several of modified magnesium hydroxide, aluminum hydroxide, ammonium polyphosphate, melamine hydrobromide, etc.

8. An environment-friendly radio wave absorbing paint according to claim 1, characterized in that, According to the ratio, after stirring evenly, an appropriate amount of pure water is added to control the viscosity of the coating, so that it can be better coated on the surface of the base material.

9. The preparation method of an environment-friendly radio wave absorbing coating according to any one of claims 1-8, characterized in that, It includes the following steps: Step S1, weigh the electromagnetic wave absorber and the dispersant powder according to the ratio, and place them in a grinder for grinding to obtain mixture 1; Step S2, use a high-speed stirrer to keep the flame retardant powder in high-speed stirring rotation at a speed of 1359 r / min for 5 - 10 min. Atomize the coupling agent by atomization and evenly spray it on the surface of the flame retardant powder to obtain a uniformly modified flame retardant powder; Step S3, add a small amount of water to the styrene-acrylic emulsion, place it in a stirring tank, and stir at 1200 r / min for 5 - 10 min to effectively dilute the styrene-acrylic emulsion. Then add mixture 1 and stir and mix at a high speed of 1300 r / min for 20 - 40 min; Step S4, slowly add the flame retardant powder obtained after modification to the mixture obtained in Step 3, and at the same time, according to the oil absorption value of the flame retardant, appropriately add an appropriate amount of water to the mixer to control the viscosity of the coating and obtain wave-absorbing coatings with different viscosities.

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