Preparation method of color zinc-containing lithium smectite wave-absorbing material and application thereof

Abstract

The present application relates to wave-absorbing paint technical field, disclose a kind of preparation method and application of color zinc-containing hectorite wave-absorbing material, steps are: lithium smectite, urea and zinc salt are mixed, grinding, form mixture, then added to water, stirring is uniform, 100~160 ℃ hydrothermal reaction 5~10 h, cooling, after suction filtration wash multiple times, obtain zinc-containing lithium smectite;The zinc-containing lithium smectite, ethanol and organic pigment are mixed, grinding, high-temperature baking, obtain color zinc-containing hectorite wave-absorbing material.The material prepared by the present application has the triple effects of wave-absorbing, thickening and coloring, and can improve the application of lithium smectite in paint.

Description

Technical Field

[0001] This invention relates to the field of microwave absorbing coating technology, and in particular to a method for preparing a colored zinc-lithium saponite microwave absorbing material with microwave absorbing properties and its application. Background Technology

[0002] With the development of electronic information technology, electromagnetic pollution has become an increasingly prominent problem. Applying microwave-absorbing coatings, which are made by combining microwave-absorbing materials with polymer coatings, to the surfaces of equipment and buildings can absorb electromagnetic waves, reduce electromagnetic interference and pollution, and is an effective means of attenuating electromagnetic energy. It has promising applications in electronics, military, and other fields.

[0003] Microwave-absorbing materials are generally gray or black. To obtain brightly colored microwave-absorbing coatings, organic pigments are often added. However, organic pigments suffer from uneven dispersion and are prone to fading under natural conditions. To address this, patent CN116693846A proposes a method for preparing a colored Mayan blue-like pigment with microwave-absorbing properties by using attapulgite as a carrier, loading polyaniline, adding organic pigments, and baking. The organic pigment molecules enter the attapulgite, improving its weather resistance, but the microwave-absorbing performance still needs further improvement.

[0004] Lithium saponite is a synthetic inorganic magnesium lithium silicate crystal with a montmorillonite structure. When added to water, it swells to form a three-dimensional network gel containing a large amount of water, and is widely used in coatings as a thickener and protective colloid. When lithium saponite is used as a protective colloid in coatings, viscosity reducers such as sodium pyrophosphate and sodium hexametaphosphate need to be added to improve the stability and applicability of the colloid, forming a low-viscosity, more stable colloidal solution (CN105860590A). However, these viscosity reducers are easily hydrolyzed in water into sodium orthophosphate, which has no viscosity-reducing properties. At the same time, the protective colloid has limited coating ability for colored particles, and problems such as bleeding, swelling, and agglomeration are prone to occur. Patent CN105860590A proposes to use hydrophobic organic compounds such as hexadecyltrimethylammonium bromide and other organic ammonium salts to modify lithium saponite, and then use hydrophilic polymers such as sodium hydroxymethyl cellulose and polyvinyl alcohol to modify it to solve the problems of thickening and bleeding. Summary of the Invention

[0005] Purpose of the invention: To address the problems existing in the prior art, this invention provides a method for preparing colored zinc-containing lithium saponite microwave absorbing material and its application. The material prepared by this invention has the triple functions of microwave absorption, thickening, and coloring, which can improve the application of lithium saponite in coatings.

[0006] Technical solution: On the one hand, the present invention provides a method for preparing a colored zinc-lithium saponite microwave absorbing material, comprising the following steps:

[0007] S1: Mix lithium saponite, urea and zinc salt, grind them to form a mixture, then add them to water, stir evenly, and perform a hydrothermal reaction at 100~160℃ for 5~10 h. After cooling, filter and wash with water several times to obtain zinc-containing lithium saponite.

[0008] S2: Mix the zinc-lithium soapstone, ethanol and organic pigment, grind and bake at high temperature to obtain colored zinc-lithium soapstone microwave absorbing material.

[0009] Furthermore, in S1, the mass ratio of lithium saponite, urea and zinc salt is 3:1:0.5~1.5.

[0010] Furthermore, the zinc salt is one of zinc chloride, zinc sulfate, or zinc nitrate.

[0011] Furthermore, in S1, the mass-to-volume ratio of the mixture to water is 8-15%.

[0012] Further, in S2, the mass ratio of the zinc-containing lithium saponite, ethanol and organic pigment is 1:0.5~1:0.05~0.15.

[0013] Preferably, the organic pigment is one of indigo, methylene blue, Congo red, or indigo.

[0014] Furthermore, in S2, the high-temperature baking specifically refers to baking at 150~240℃ for 5~15 hours.

[0015] On the other hand, the present invention also provides an application of the colored zinc-lithium saponite absorbing material prepared by any of the above methods in a microwave absorbing coating: the colored zinc-lithium saponite absorbing material is mixed evenly with epoxy resin and curing agent, and then cured to obtain a microwave absorbing coating.

[0016] Furthermore, the mass ratio of the colored zinc-lithium saponite microwave absorbing material to epoxy resin and curing agent is 2:2~2.5:0.4~0.6.

[0017] Beneficial effects: The synthesis principle of this invention is as follows:

[0018] Lithium soapstone is mixed with urea and zinc salts, Zn 2+ Urea enters the lithium saponite in hydrated ion form, decomposes under hydrothermal conditions, and forms an alkaline environment, Zn 2+ The homogeneous precipitation transforms into basic zinc carbonate, which enters the interior or surface of lithium saponite, resulting in zinc-containing lithium saponite. Subsequently, organic pigments are dissolved in ethanol and intercalated into the interlayer structure of the zinc-containing lithium saponite. After high-temperature baking, they are further fixed inside the lithium saponite.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) High-temperature baking is used to solidify the colored pigment inside the lithium saponite. The O and N atoms in the organic pigment can form coordination bonds with the metal ions exposed by high-temperature dehydration inside the lithium saponite, which greatly improves the weather resistance and stability of the pigment and enhances its colorability.

[0021] (2) Colored zinc-containing lithium saponite loaded with zinc carbonate has microwave absorption properties. When used in coatings, it also has thickening and microwave absorption functions. Because the surface is loaded with organic pigments, the organic groups of the pigments improve the hydrophobicity of lithium saponite. At the same time, the loaded zinc carbonate solid particles can reduce the viscosity of lithium saponite, thus reducing the use of viscosity reducers. Attached image description:

[0022] Figure 1 The XRD pattern of the blue zinc-lithium saponite microwave absorbing material prepared in Embodiment 1;

[0023] Figure 2 The microwave absorption performance curve of the blue zinc-lithium saponite microwave absorbing material prepared in Implementation Method 1 when applied as a microwave absorbing coating. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the embodiments.

[0025] Implementation method 1:

[0026] This embodiment provides a method for preparing a colored zinc-lithium saponite microwave absorbing material, as detailed below:

[0027] Lithium saponite, urea, and zinc chloride were mixed in a mass ratio of 3:1:0.5 and milled for 20-30 minutes to form a mixture. Then, 10% of the mixture was added to distilled water, stirred evenly, placed in a reaction vessel, sealed, and placed in an oven at 100°C for 10 hours. After cooling, the mixture was filtered and washed several times with water to obtain zinc-containing lithium saponite. The zinc-containing lithium saponite, ethanol, and methylene blue were mixed in a mass ratio of 1:0.5:0.05, milled for 20 minutes, and then baked in an oven at 150°C for 15 hours to obtain a blue zinc-containing lithium saponite microwave absorbing material.

[0028] Figure 1 The XRD pattern of the blue zinc-containing lithium saponite microwave absorbing material prepared in this embodiment shows that the zinc-containing compound is zinc carbonate.

[0029] This embodiment also provides an application of a colored zinc-lithium saponite microwave absorbing material in a microwave absorbing coating, the specific steps of which are as follows:

[0030] Blue zinc-lithium soapstone microwave absorbing material was mixed with epoxy resin and curing agent in a mass ratio of 2:2.5:0.5 and cured to obtain a microwave absorbing coating.

[0031] The electromagnetic parameters of the above-mentioned absorbing coating were tested using a vector network analyzer: Figure 2 The absorption performance curves show that the sample exhibits good absorption performance in the 8~18GHz range (effective reflection loss ≤ -5 dB), and its reflection loss can reach -27 dB when the coating thickness is 3 mm.

[0032] Implementation Method 2:

[0033] This embodiment provides a method for preparing a colored zinc-lithium saponite microwave absorbing material, as detailed below:

[0034] Lithium saponite, urea, and zinc sulfate were mixed in a mass ratio of 3:1:0.8 and milled for 20-30 minutes to form a mixture. Then, 10% of the mixture was added to distilled water, stirred evenly, placed in a reaction vessel, sealed, and placed in an oven at 120°C for 8 hours. After cooling, the mixture was filtered and washed several times with water to obtain zinc-containing lithium saponite. The zinc-containing lithium saponite, ethanol, and indigo were mixed in a mass ratio of 1:1:0.1, milled for 25 minutes, and then baked in an oven at 180°C for 10 hours to obtain a blue zinc-containing lithium saponite microwave absorbing material.

[0035] Implementation Method 3:

[0036] This embodiment provides a method for preparing a colored zinc-lithium saponite microwave absorbing material, as detailed below:

[0037] Lithium saponite, urea, and zinc nitrate were mixed in a mass ratio of 3:1:1.2 and milled for 20-30 minutes to form a mixture. Then, 10% of the mixture was added to distilled water, stirred evenly, placed in a reaction vessel, sealed, and placed in an oven at 140°C for 6 hours. After cooling, the mixture was filtered and washed several times with water to obtain zinc-containing lithium saponite. The zinc-containing lithium saponite, ethanol, and Congo red were mixed in a mass ratio of 1:1.2:0.12, milled for 30 minutes, and then baked in an oven at 200°C for 8 hours to obtain a brownish-red zinc-containing lithium saponite microwave absorbing material.

[0038] Implementation Method 4:

[0039] This embodiment provides a method for preparing a colored zinc-lithium saponite microwave absorbing material, as detailed below:

[0040] Lithium saponite, urea, and zinc nitrate were mixed in a mass ratio of 3:1:1.5 and milled for 20-30 minutes to form a mixture. Then, 10% of the mixture was added to distilled water, stirred evenly, placed in a reaction vessel, sealed, and placed in an oven at 160°C for 5 hours. After cooling, the mixture was filtered and washed several times with water to obtain zinc-containing lithium saponite. The zinc-containing lithium saponite, ethanol, and indigo were mixed in a mass ratio of 1:1.5:0.15, milled for 20 minutes, and then baked in an oven at 240°C for 5 hours to obtain a red zinc-containing lithium saponite microwave absorbing material.

[0041] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a color-containing zinc lithium phlogopite wave-absorbing material, characterized in that, Includes the following steps: S1: Mix lithium saponite, urea and zinc salt, grind them to form a mixture, then add them to water, stir evenly, and perform a hydrothermal reaction at 100~160℃ for 5~10 h. After cooling, filter and wash with water several times to obtain zinc-containing lithium saponite. S2: Mix the zinc-lithium soapstone, ethanol and organic pigment, grind and bake at high temperature to obtain colored zinc-lithium soapstone microwave absorbing material; wherein, the high temperature baking is specifically: baking at 150~240℃ for 5~15 h.

2. The method for preparing the colored zinc-lithium saponite microwave absorbing material according to claim 1, characterized in that: In S1, the mass ratio of lithium saponite, urea and zinc salt is 3:1:0.5~1.

5.

3. The method for preparing the colored zinc-lithium saponite microwave absorbing material according to claim 2, characterized in that: The zinc salt is one of zinc chloride, zinc sulfate, or zinc nitrate.

4. The method for preparing the colored zinc-lithium saponite microwave absorbing material according to claim 1, characterized in that: In S2, the mass ratio of the zinc-containing lithium saponite, ethanol and organic pigment is 1:0.5~1:0.05~0.

15.

5. The method for preparing the colored zinc-lithium saponite microwave absorbing material according to claim 4, characterized in that: The organic pigment is one of indigo, methylene blue, Congo red, or indigo.

6. The application of a colored zinc-lithium saponite microwave absorbing material prepared by the method according to any one of claims 1-5 in a microwave absorbing coating, characterized in that: The colored zinc-lithium soapstone microwave absorbing material is mixed evenly with epoxy resin and curing agent, and then cured to obtain a microwave absorbing coating.

7. The application of the colored zinc-lithium saponite absorbing material according to claim 6 in a microwave absorbing coating, characterized in that: The mass ratio of the colored zinc-lithium saponite microwave absorbing material to epoxy resin and curing agent is 2:2~2.5:0.4~0.6.

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