High-hydrophobicity wave-transparent plate and preparation method thereof
By grafting fluorine-containing segments in polyurea molecules and surface treatment with low surface energy polymers, the problem that existing wave-transmissive materials are difficult to have high wave transmittance, good mechanical properties and high hydrophobic properties, and efficient electromagnetic wave transmission and self-cleaning properties are achieved.
Patent Information
- Application Number
- CN202411897657.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-04-04
AI Technical Summary
While existing wave-transmitting materials have high wave transmittance and good mechanical properties, it is difficult to achieve high hydrophobic performance, especially in applications in aerodynamic loads and harsh climates.
By grafting fluorine-containing segments in the polyurea molecule to reduce molecular polarity, combining low-surface energy polyvinylidene chloride with epoxy resin for surface treatment, forming a plate with high hydrophobic and wave-transmissive properties.
It realizes the high wave transmittance and good hydrophobic properties of polyurea substrates, and is suitable for structural/functional integrated composite materials, with self-cleaning, waterproofing, anti-icing and other application scenarios.
Smart Images
Figure CN119751952A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of wave-transmitting composite materials, and in particular relates to a highly hydrophobic wave-transmitting plate and a preparation method thereof. Background Art
[0002] As an important component of the current structural / functional integrated design in the aerospace field, wave-transmitting material technology needs to achieve high wave transmittance in a wide frequency band, and withstand aerodynamic loads and harsh climate environments. Wave-transmitting materials can generally be divided into two categories: inorganic materials and organic materials. Inorganic materials include ceramic materials such as alumina, quartz, and silicon nitride, and organic materials include traditional resins, high-temperature resistant resins, and fiber-reinforced resins. Although ceramic wave-transmitting materials have good wave-transmitting effects, they have the defects of heavy weight and poor toughness; most organic wave-transmitting materials have the advantages of light weight and corrosion resistance, but their use as structural support materials is often restricted by mechanical properties.
[0003] Polyurea not only has good hydrophobic properties, but also has excellent mechanical properties. It can absorb impact energy generated by external forces efficiently, and its construction process is simple and fast. It is an ideal structural wave-transmitting material. The effect of wave-transmitting materials on the transmittance of electromagnetic waves depends on the dielectric constant of the material. The lower the dielectric constant, the higher the wave transmittance. There are a large number of carbamate groups in the molecules of polyurea materials. The larger polarity of the carbamate groups causes the higher dielectric constant of polyurea, which is not conducive to the high transmittance of electromagnetic waves. There have been no public reports on the introduction of weakly polar fluorinated compounds into polyurea materials to reduce their dielectric constants, and further surface treatment of them with low surface energy polymers to obtain materials with both good hydrophobic and wave-transmitting properties. Summary of the invention
[0004] Purpose of the present invention: The present invention relates to a highly hydrophobic wave-transparent sheet material and a surface treatment method thereof, which reduces the molecular polarity of the polyurea substrate by grafting fluorine-containing segments into the polyurea molecule, thereby improving the wave transmittance. In order to further improve the hydrophobicity of the polyurea substrate, the present invention uses low-surface-energy polyvinylidene fluoride to perform surface treatment on it, and introduces epoxy resin to enhance the adhesion of the two, thereby obtaining a wave-transparent sheet material with good hydrophobicity, which is suitable for a structural / functional integrated composite material with a load-bearing function.
[0005] The present invention is achieved through the following technical solutions.
[0006] According to a first aspect of the present invention, a highly hydrophobic wave-transmitting sheet material is provided, comprising a fluorinated polyurea substrate and a low surface energy thin film coating coated on the surface of the fluorinated polyurea substrate.
[0007] In a possible embodiment, the low surface energy thin film coating is a mixture of polyvinylidene chloride and epoxy resin dissolved in a solvent N'N-dimethylformamide at a mass ratio of 1.0 to 2.5.
[0008] In a possible embodiment, the thickness of the plate is in the range of 0.5 to 1 cm, and has the functional characteristics of being hydrophobic and wave-transparent.
[0009] According to a second aspect of the present invention, a method for preparing a highly hydrophobic wave-transmitting plate is provided, which specifically comprises the following steps:
[0010] (1) mixing polyetheramine and polysiloxane at a mass ratio of 1.8 to 3.0 at room temperature, heating to 80 to 100° C. and keeping the temperature for 30 to 60 minutes to obtain a flexible polyetheramine raw material with a low dielectric constant;
[0011] (2) mixing hexamethylenediamine and ethyl isocyanate acrylate in a mass ratio of 1 to 1.5, reacting at 1 to 10° C. for 30 to 60 minutes to obtain a capping monomer;
[0012] (3) the flexible polyetheramine obtained in step (1) is mixed with diisocyanate at a functional group ratio of 1 to 1.2, 5 to 10% by mass of dimethylol propionic acid as a chain extender is added, and after reacting at 1 to 10° C. for 30 to 60 minutes, 5 to 15% by mass of perfluoroethyloctanol is added for grafting, 10 to 15% by mass of the end-capping monomer obtained in step (2) is added and the reaction is continued for 10 to 30 minutes, and then water is added for shear dispersion to obtain a fluorinated polyurea slurry;
[0013] (4) applying multi-layer coating and drying the fluorinated polyurea slurry obtained in step (3) by a flat plate coating method to obtain a fluorinated polyurea substrate with a thickness of 0.5 to 1 cm;
[0014] (5) The low surface energy thin film coating is prepared by dissolving polyvinylidene chloride and epoxy resin in a solvent N'N-dimethylformamide at a mass ratio of 1.0 to 2.5, spraying the mixed solution evenly on the surface of the polyurea substrate, and drying at 60 to 80° C. to obtain a highly hydrophobic wave-transparent sheet.
[0015] Preferably, the polysiloxane is polydimethylsiloxane or 1,3-bis(3-glycidylpropyl)-1,1,3,3-tetramethyldisiloxane.
[0016] Preferably, the diisocyanate is one or any combination of isophorone diisocyanate, diphenylmethane diisocyanate, and hexamethylene diisocyanate.
[0017] The function of the polyvinylidene chloride is to further reduce the surface energy of the polyurea substrate; the function of the epoxy resin is to enhance the film-forming property of the polyvinylidene chloride and its adhesion to the surface of the polyurea substrate.
[0018] The highly hydrophobic wave-transmitting plate is suitable for the self-cleaning, waterproofing, and anti-icing of wave-transmitting structures.
[0019] The present invention firstly uses flexible polysiloxane to modify polyetheramine, thereby enhancing the flexibility of polyurea molecular segments and improving the mechanical properties of polyurea matrix; further, fluorine-containing segments are introduced into polyurea segments to reduce the polarity of polyurea molecules, thereby reducing its dielectric constant, and achieving an average wave transmittance of more than 85% in the X-band. Compared with the prior art, the present application uses polysiloxane to modify polyetheramine, which significantly improves the flexibility and elasticity of polyurea, so that the obtained polyurea substrate has both good mechanical tensile strength and tear strength, which plays an important role in the polyurea substrate to cope with external mechanical impact; the wave transmittance of organic materials depends on the dielectric constant of the material itself, and the strong molecular polarity of polyurea leads to its high dielectric constant. Grafting low molecular polarity perfluoroethyloctanol into polyurea molecules can significantly reduce the molecular polarity of the polyurea matrix, reduce its dielectric constant, and increase the average wave transmittance of the polyurea matrix in the X-band to more than 85%, and the reflectivity is low.
[0020] A large number of carbamate segments in the polyurea molecule itself have good waterproof properties, but its hydrophobic properties are easily affected by processing technology. In order to further improve the hydrophobic properties of polyurea, the present application introduces low surface energy polymer polyvinylidene chloride to modify the surface of the polyurea substrate. However, due to the poor film-forming property of polyvinylidene chloride and weak adhesion to the polyurea substrate, the present application combines polyvinylidene chloride with epoxy resin to form a hydrophobic coating on the surface of the polyurea substrate, and uses epoxy resin to improve the film-forming property of polyvinylidene chloride and its adhesion to the polyurea substrate, so that the water contact angle of the polyurea sheet reaches 128°, with good hydrophobic properties, which is beneficial to the self-cleaning, waterproof, anti-icing and other application scenarios of the material. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is based on the X-band transmittance of the plate obtained in Example 2;
[0022] Figure 2 It is based on the reflectivity of the plate obtained in Example 2 in the X-band;
[0023] Figure 3 This is a water contact angle test diagram of the plate obtained in Example 3. DETAILED DESCRIPTION
[0024] In order to have a clearer understanding of the technical features of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.
[0025] Example 1
[0026] (1) Polyetheramine and polydimethylsiloxane were uniformly mixed at room temperature in a mass ratio of 1.8, and the temperature was raised to 80° C. and kept for 30 minutes to obtain a modified polyetheramine.
[0027] (2) Hexamethylenediamine and ethyl isocyanate acrylate were mixed at a mass ratio of 1.0 and reacted at 1° C. for 30 minutes to obtain a capping monomer.
[0028]
[0029] (3) The modified polyetheramine and isophorone diisocyanate were mixed at a functional group ratio of 1.0, 5% by mass of dihydroxymethylpropionic acid was added, and the mixture was reacted at 1°C for 30 minutes. Then, 5% by mass of perfluoroethyloctanol and 10% of the end-capping monomer were added and the reaction was continued for 10 minutes. Then, water was added and sheared to obtain a polyurea slurry. The slurry was multi-layered and dried by a flat plate coating method to obtain a polyurea substrate with a thickness of 0.5 cm.
[0030]
[0031] (4) Dissolve polyvinylidene chloride and epoxy resin in a solvent N'N-dimethylformamide at a mass ratio of 1.0, spray the mixed solution evenly on the polyurea substrate, and dry at 60° C. to obtain a hydrophobic wave-transparent sheet.
[0032] Example 2
[0033] (1) Polyetheramine and polydimethylsiloxane were uniformly mixed at room temperature in a mass ratio of 2.0, and the temperature was raised to 90° C. and kept for 40 minutes to obtain a modified polyetheramine.
[0034] (2) Hexamethylenediamine and ethyl isocyanate acrylate were mixed in a mass ratio of 1.2 and reacted at 5° C. for 40 minutes to obtain a capping monomer.
[0035] (3) The modified polyetheramine and diphenylmethane diisocyanate were mixed at a functional group ratio of 1.1, 8% by mass of dihydroxymethylpropionic acid was added, and the mixture was reacted at 5°C for 40 minutes. Then, 10% by mass of perfluoroethyloctanol and 12% by mass of a capping monomer were added and the reaction was continued for 20 minutes. Then, water was added to shear and disperse the mixture to obtain a polyurea slurry. The slurry was multi-layered and dried using a flat plate coating method to obtain a polyurea substrate with a thickness of 0.6 cm.
[0036] (4) Dissolve polyvinylidene chloride and epoxy resin in a solvent N'N-dimethylformamide at a mass ratio of 1.5, spray the mixed solution evenly on the polyurea substrate, and dry at 70° C. to obtain a hydrophobic wave-transparent sheet.
[0037] Example 3
[0038] (1) Polyetheramine and polydimethylsiloxane were uniformly mixed at room temperature in a mass ratio of 3.0, and the temperature was raised to 100° C. and kept for 60 minutes to obtain a modified polyetheramine.
[0039] (2) Hexamethylenediamine and ethyl isocyanate acrylate were mixed at a mass ratio of 1.5 and reacted at 10° C. for 60 minutes to obtain a capping monomer.
[0040] (3) The modified polyetheramine and isophorone diisocyanate were mixed at a functional group ratio of 1.2, 10% by mass of dihydroxymethylpropionic acid was added, and the mixture was reacted at 10°C for 30 minutes. Then, 15% by mass of perfluoroethyloctanol and 15% of a capping monomer were added and the reaction was continued for 30 minutes. Then, water was added and sheared to obtain a polyurea slurry. The slurry was multi-layered and dried by a flat plate coating method to obtain a polyurea substrate with a thickness of 1 cm.
[0041] (4) Dissolve polyvinylidene chloride and epoxy resin in a solvent N'N-dimethylformamide at a mass ratio of 2.5, spray the mixed solution evenly on the polyurea substrate, and dry at 80° C. to obtain a hydrophobic wave-transparent sheet.
[0042] Example 4
[0043] (1) Polyetheramine and 1,3-bis(3-glycidylpropyl)-1,1,3,3-tetramethyldisiloxane were uniformly mixed at room temperature in a mass ratio of 2.0, and the temperature was raised to 90° C. and kept for 40 minutes to obtain a modified polyetheramine.
[0044] (2) Hexamethylenediamine and ethyl isocyanate acrylate were mixed in a mass ratio of 1.2 and reacted at 5° C. for 40 minutes to obtain a capping monomer.
[0045] (3) The modified polyetheramine and isophorone diisocyanate were mixed at a functional group ratio of 1.1, 8% by mass of dihydroxymethylpropionic acid was added, and the mixture was reacted at 5°C for 40 minutes. Then, 10% by mass of perfluoroethyloctanol and 12% by mass of a capping monomer were added and the reaction was continued for 20 minutes. Then, water was added and sheared to obtain a polyurea slurry. The slurry was multi-layered and dried by a flat plate coating method to obtain a polyurea substrate with a thickness of 0.5 cm.
[0046] (4) Dissolve polyvinylidene chloride and epoxy resin in a solvent N'N-dimethylformamide at a mass ratio of 1.5, spray the mixed solution evenly on the polyurea substrate, and dry at 70° C. to obtain a hydrophobic wave-transparent sheet.
[0047] Comparative Example 1
[0048] (1) Hexamethylenediamine and ethyl isocyanate acrylate were mixed in a mass ratio of 1.2 and reacted at 5° C. for 40 minutes to obtain a capping monomer.
[0049] (2) Polyetheramine and isophorone diisocyanate were mixed at a functional group ratio of 1.1, 8% by mass of dihydroxymethylpropionic acid was added, and the mixture was reacted at 5°C for 40 minutes, followed by adding 12% of a capping monomer and continuing the reaction for 20 minutes. Water was then added and sheared to obtain a polyurea slurry. The slurry was coated with multiple layers and dried using a flat plate coating method to obtain a polyurea sheet with a thickness of 0.5 cm.
[0050] The average wave transmittance and hydrophobic performance parameters of the plates obtained in Examples 1 to 4 and Comparative Example 1 in the X-band are listed in Table 1. The results show that the introduction of the fluorine-containing segment significantly enhances the wave transmittance of the polyurea plate, and the surface modification of the polyurea substrate by combining low surface energy polyvinylidene chloride with epoxy resin effectively increases the water contact angle and enhances the hydrophobic performance of the plate.
[0051] Table 1 Wave absorption performance parameters of the samples obtained in the embodiments and comparative examples
[0052] Example Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Average wave transmittance (%) 79.3 85.3 82.2 80.5 73.6 Water contact angle (°) 111 121 128 125 98
Claims
1. A highly hydrophobic wave-transmitting plate, characterized in that: The invention comprises a fluorine-containing polyurea substrate and a low surface energy thin film coating coated on the surface of the fluorine-containing polyurea substrate.
2. The highly hydrophobic wave-transmitting plate according to claim 1, characterized in that: The low surface energy thin film coating is a mixture of polyvinylidene chloride and epoxy resin dissolved in a solvent N'N-dimethylformamide at a mass ratio of 1.0 to 2.
5.
3. The highly hydrophobic wave-transmitting plate material according to claim 1, characterized in that: The structural formula of the fluorine-containing polyurea substrate is.
4. A method for preparing a highly hydrophobic wave-permeable plate, used for preparing a highly hydrophobic wave-permeable plate according to any one of claims 1 to 3, characterized in that: The specific steps include: 2-1 The polyetheramine and polysiloxane are uniformly mixed at a mass ratio of 1.8 to 3.0 at room temperature, and the temperature is raised to 80 to 100° C. and kept for 30 to 60 minutes to obtain a flexible polyetheramine raw material with a low dielectric constant; 2-2 Hexamethylenediamine and ethyl isocyanate acrylate are mixed in a mass ratio of 1 to 1.5, and reacted at 1 to 10° C. for 30 to 60 minutes to obtain a capping monomer; 2-3 The flexible polyetheramine obtained in step 2-1 is mixed with diisocyanate at a functional group ratio of 1 to 1.2, 5 to 10% by mass of dimethylol propionic acid as a chain extender is added, and after reacting at 1 to 10° C. for 30 to 60 minutes, 5 to 15% by mass of perfluoroethyloctanol is added for grafting, and 10 to 15% by mass of the end-capping monomer obtained in step 2-2 is added to continue the reaction for 10 to 30 minutes, and then water is added for shear dispersion to obtain a fluorinated polyurea slurry; 2-4 The polyurea slurry obtained in step 2-3 is subjected to multi-layer coating and drying by a flat plate coating method to obtain a fluorine-containing polyurea substrate with a thickness of 0.5 to 1 cm; 2-5 The low surface energy thin film coating is prepared by dissolving polyvinylidene chloride and epoxy resin in a solvent N'N-dimethylformamide at a mass ratio of 1.0 to 2.5, spraying the mixed solution evenly on the surface of the fluorinated polyurea substrate, and drying at 60 to 80°C to obtain a highly hydrophobic wave-transparent sheet.
5. The method for preparing a highly hydrophobic wave-transmitting sheet material according to claim 4, characterized in that: The polysiloxane is one of polydimethylsiloxane and 1,3-bis(3-glycidylpropyl)-1,1,3,3-tetramethyldisiloxane.
6. The method for preparing a highly hydrophobic wave-transmitting plate according to claim 4, characterized in that: The diisocyanate is one or any combination of isophorone diisocyanate, diphenylmethane diisocyanate and hexamethylene diisocyanate.
7. The method for preparing a highly hydrophobic wave-transmitting sheet material according to claim 4, characterized in that: The function of the polyvinylidene chloride is to further reduce the surface energy of the polyurea substrate; the function of the epoxy resin is to enhance the film-forming property of the polyvinylidene chloride and its adhesion to the surface of the polyurea substrate.
8. The method for preparing a highly hydrophobic wave-transmitting sheet material according to claim 4, characterized in that: The highly hydrophobic wave-transmitting sheet is suitable for the application scenarios of self-cleaning, waterproof and anti-icing wave-transmitting structures.