Preparation method of multifunctional coating material with self-early-warning, corrosion-resistant, self-repairing and wave-absorbing characteristics

Abstract

A preparation method of a multifunctional coating material with self-warning, corrosion-resistant, self-repairing and wave-absorbing characteristics comprises the following steps: dispersing 5-10g of carbonyl iron into water, and mechanically stirring to obtain a solution A; dissolving 2-8 g of an isocyanate monomer with the functionality being 2 or above, 0.3-2 g of an oil-soluble early warning agent and 1-10 g of a self-repairing agent in a mixed solvent composed of 2-8 g of an oily solvent and 5-12 g of tetraethyl silicate to obtain a solution B; adding the solution B into the solution A for emulsification, and adding 5-15mL of a double-selenium dihydric alcohol aqueous solution; carrying out water bath reaction, and drying to obtain multifunctional wave-absorbing particles; and uniformly dispersing in a matrix to obtain a viscous liquid, removing bubbles, and curing. According to the invention, special groups are introduced into a microcapsule shell material and the composition of a core material is changed, so that the multifunctionality of the microcapsule can be realized, a metal-based absorbing material and other functional components are assembled into the microcapsule, and the multifunctional microwave absorbing material with self-warning and corrosion resistance is developed.

Description

Technical Field

[0001] The invention relates to a method for preparing a multifunctional coating material with self-warning, corrosion resistance, self-repairing and wave absorption properties. Background Art

[0002] With the widespread application of wireless communication technology, electromagnetic radiation and pollution problems have become increasingly serious, which not only interfere with the normal operation of electronic equipment, but also cause irreversible damage to human health. In order to solve the pollution problem, it is urgent to develop high-performance microwave absorbing materials. In recent years, people have developed various micro-nanoscale absorbing materials and structures based on conductive polymers, carbon-based and metal-based materials, which have shown excellent absorption performance in applications such as electronic equipment, aircraft and warships. Among various microwave absorbing materials, metal-based absorbing materials have attracted much attention due to their rich resources, high magnetic loss and high magnetic permeability. They are currently one of the most widely used commercial absorbing materials.

[0003] However, in practical applications, environmental corrosion and damage to metal-based absorbers will shorten their service life and greatly affect their absorbing ability. Researchers have adopted a variety of strategies to extend the service life of metal-based absorbers, but they cannot completely prevent corrosion. If it is possible to provide early warning for damage to absorbing materials, intuitively reflect the degree of corrosion through different warning signals, and provide corrosion inhibition measures after the alarm is issued, creating a time window for artificial repair of materials, it will effectively reduce the losses caused by corrosion damage to absorbing materials. It is worth noting that integrating functions such as self-warning, corrosion resistance, self-repair, and absorbing into coating materials is not a simple stacking of multiple coatings, but rather giving materials new functions without damaging or even enhancing the original properties of the materials. At present, it is still a major challenge to effectively integrate multiple functions into one material, which depends on the composition, structure, and clever design of the material. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the background technology and to provide a method for preparing a multifunctional coating material with self-warning, corrosion resistance, self-repairing and wave absorption characteristics.

[0005] In recent years, microcapsules with core-shell structures have been widely used in the fields of self-repair, stimulus response and corrosion protection. The present invention can realize the multifunctionality of microcapsules by introducing special groups into the microcapsule shell material and changing the composition of the core material. The metal-based absorption material and other functional components are assembled into "microcapsules" to develop multifunctional microwave absorption materials with self-warning and corrosion resistance, which effectively solves the corrosion problem.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a multifunctional coating material with self-warning, corrosion resistance, self-repairing and wave absorption characteristics, the method comprising:

[0008] Step 1: Preparation of multifunctional wave-absorbing particles: 5-10 g of carbonyl iron is dispersed in 50-200 mL of water and mechanically stirred to obtain solution A; 2-8 g of isocyanate monomer with a functionality of 2 or more, 0.3-2 g of oil-soluble early warning agent, and 1-10 g of self-healing agent are dissolved in a mixed solvent consisting of 2-8 g of oily solvent and 5-12 g of tetraethyl silicate (TEOS) or tetraethyl titanate to obtain solution B; solution B is added to solution A for emulsification, and 5-15 mL of 40 wt.% diselenide diol (HOC) is added. 3 H 6 Se) 2 Aqueous solution; react in a water bath, use a sieve to remove excess carbonyl iron CIP, the product particle size is 440-460μm, and the CIP particle size is 1-5μm. After the product is dried, microcapsule-type multifunctional wave-absorbing particles with CIP as an emulsifier are obtained; (HOC 3 H 6 Se) 2 Interfacial polymerization occurs with PAPI at the Pickering emulsion interface to form an organic wall material (inner shell), which gives CIP-M the ability to resist Fe 3+ Response characteristics;

[0009] Step 2: Preparation and use of coating: Disperse the multifunctional absorbing particles evenly in the matrix, stir evenly to obtain a viscous and uniform liquid, remove bubbles, pour into a mold and solidify to obtain a multifunctional coating material.

[0010] Furthermore, in step one, the isocyanate monomer with a functionality of 2 or more is one of polymethylene polyphenyl polyisocyanate (PAPI), diphenylmethane diisocyanate or toluene diisocyanate; the early warning agent is rhodamine B or o-phenanthroline; the self-healing agent is isophorone diisocyanate or toluene diisocyanate; the oily solvent is one of butanone, cyclohexanol, cyclohexanone or isophorone.

[0011] Furthermore, in step 1, the rotation speed of the mechanical stirring is 100-800 rpm / min.

[0012] Furthermore, in step 1, the emulsification speed is 100-1000 rpm / min, and the time is 10-80 minutes.

[0013] Furthermore, in step 1, the temperature of the water bath reaction is 30-90° C., and the time is 5-12 hours.

[0014] Furthermore, in step 1, the drying temperature is 30-60° C. and the drying time is 10-60 minutes.

[0015] Furthermore, in step 2, the substrate is an epoxy rigid substrate or a flexible substrate. The epoxy rigid substrate is a mixture of epoxy resin substrates E44, E51, AFG-90, TDE-85 with amine curing agents and anhydride curing agents; the flexible substrate, such as polydimethylsiloxane, can be used as an adaptive multifunctional absorbing cloth to conceal various important equipment by simply covering it. In addition, the above mixture containing multifunctional absorbing particles can also be sprayed and applied to various complex devices and equipment.

[0016] Furthermore, in step 2, the mass fraction of the multifunctional wave-absorbing particles in the viscous and uniform liquid is 10%-50%.

[0017] Furthermore, in step 2, the degassing is performed by vacuum treatment for 5-80 minutes to remove the entrained air.

[0018] Furthermore, in step 2, the curing temperature is 20-120° C. and the curing time is 2-50 hours.

[0019] The beneficial effects of the present invention compared with the prior art are as follows: CIP has excellent wave absorbing performance, and its innovative use as an emulsifier can simultaneously play an emulsifying function and avoid the introduction of redundant materials. At the same time, the capsule particles produced by it as the outer wall have a wave absorbing function, and the production of capsules increases the wave absorbing effect. Oil-soluble rhodamine B and phenolphthalein dissolution can simultaneously serve as early warning agents and anti-corrosion properties, and isophorone diisocyanate or toluene diisocyanate can be repaired after the diselenide bond is broken. Through ingenious design, multiple functions such as self-warning, corrosion resistance, self-repair, and wave absorbing properties are integrated into the coating material without increasing the difficulty of preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The SEM images of the multifunctional wave-absorbing particles obtained after the reaction (different magnifications);

[0021] Figure 2 This is a diagram showing the warning effect (under 254nm and visible light) of the absorbing coating at different times and with different addition amounts;

[0022] Figure 3 It is a comparison diagram of the wave absorption effect of pure CIP and the present invention at 0 day and 45 days. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0024] Embodiment 1:

[0025] Step 1: Preparation of multifunctional wave-absorbing particles: Disperse 7.5 grams of carbonyl iron in a three-necked flask containing 100 milliliters of aqueous solution and stir mechanically at a speed of 400 rpm / min. Dissolve 4 grams of polymethylene polyphenyl polyisocyanate (PAPI), 0.7 grams of oil-soluble rhodamine B, and 8 grams of toluene diisocyanate in a mixed solvent consisting of 4 grams of cyclohexanone and 8 grams of tetraethyl silicate (TEOS). Add the above mixed solution to a three-necked flask and then emulsify at a speed of 400 rpm for 35 minutes. After the emulsification is completed, add 10 milliliters of 40% mass fraction (HOC 3 H 6 Se) 2 After the addition was completed, the water bath temperature was raised to 60°C and the reaction was continued for 9 hours. Before filtering the product, a sieve was used to remove excess CIP. Finally, the sample was dried at 40°C for 30 minutes to obtain microcapsule-type multifunctional wave-absorbing particles with CIP as an emulsifier.

[0026] Step 2: Preparation and use of coating: The multifunctional wave-absorbing particles are evenly dispersed in the matrix, stirred evenly to obtain a viscous and uniform liquid, vacuum treated for 10 minutes to remove the entrained air, poured into a mold and cured at 25°C for 48 hours to obtain a multifunctional coating material. The matrix used is a mixture of epoxy resin E44 and D230 in a ratio of 5:1. The mass fraction of the multifunctional wave-absorbing particles in the viscous and uniform liquid is 15%.

[0027] Figure 1 a shows the scanning electron microscope image (SEM) of CIP-M. CIP-M presents a spherical microstructure. The particle size distribution of CIP-M is relatively uniform, mainly concentrated between 440-460μm, and the surface of CIP-M presents an obvious rough structure ( Figure 1 b), this rough structure is mainly because during the CIP-M preparation process, an organic inner shell is formed inside the CIP particle layer, and the CIP particles are semi-embedded in the inner shell.

[0028] like Figure 2As shown, under the irradiation of visible light, the optical image of the 15wt.% CIP-M-EP coating did not change significantly after corrosion. When exposed to 365nm light, no fluorescence emission was detected. This phenomenon shows that under the irradiation of visible light and 365nm light, the corrosion state of the CIP-M-EP coating is difficult to be intuitively identified, thus revealing the hysteresis characteristics of the external manifestation of coating corrosion. However, under the irradiation of 254nm light, the corroded CIP-M-EP coating can emit significant red fluorescence, while the pure EP (0wt.% CIP-M-EP) coating has no fluorescence phenomenon, which indicates that the red fluorescence originates from the CIP-M inside the absorbing coating. These results show that the CIP-M-EP coating has a self-warning function, and only under specific wavelength light conditions can the warning signal appear after corrosion, which fully demonstrates the high concealment and anti-interference of its self-warning capability. At the same time Figure 2 A comparative illustration of multifunctional absorbing particles with a mass fraction of 10% or 5% is also provided. It can be seen that the optical image of the coating with 10% multifunctional absorbing particles added is not much different from that of the coating with 15% added under visible light, 365nm and 254nm light irradiation, while there is some difference in the coating with 5% multifunctional absorbing particles added.

[0029] like Figure 3 As shown in the figure, the microwave absorption performance of the CIP-M-EP coating changes after being immersed in 1% HCl + 5wt.% NaCl solution. The maximum reflection loss (RL) value of the CIP-M-EP coating is -32.8dB, which is only 3.13dB lower than that before corrosion, indicating that its microwave absorption performance remains relatively stable. This is mainly because as the corrosion immersion time increases, the CIP on the surface of the CIP-M is corroded to generate Fe 3+ The generated Fe 3+ It can undergo redox reaction with the diselenide bond (-Se-Se-) in the inner shell of CIP-M, and -Se-Se- is opened to form pores. Some RB-H will also flow out from the damaged part of CIP-M, where the O and N atoms in the RB-H molecule can react with Fe 3+ A chelation reaction occurs to form a protective coordination compound film covering the surface of the CIP particles. This film isolates the direct contact between the CIP and the corrosive media in the external environment, reduces the corrosion rate of the CIP particles, and gives the CIP-M coating strong corrosion resistance.

[0030] Embodiment 2:

[0031] Step 1: Preparation of multifunctional wave-absorbing particles: Disperse 8 grams of carbonyl iron in a three-necked flask containing 150 milliliters of aqueous solution and stir mechanically at a speed of 500 rpm / min. Dissolve 4 grams of diphenylmethane diisocyanate, 0.7 grams of oil-soluble o-phenanthroline, and 5 grams of isophorone diisocyanate in a mixed solvent consisting of 4 grams of butanone and 8 grams of tetraethyl silicate (TEOS). Add the above mixed solution to a three-necked flask and then emulsify at a speed of 600 rpm for 40 minutes. After the emulsification is completed, add 12 milliliters of 40% mass fraction (HOC 3 H 6 Se) 2 After the addition was completed, the water bath temperature was raised to 70°C and the reaction was continued for 9 hours. Before filtering the product, a sieve was used to remove excess CIP. Finally, the sample was dried at 40°C for 30 minutes to obtain microcapsule-type multifunctional wave-absorbing particles with CIP as an emulsifier.

[0032] Step 2: Preparation and use of coating: The multifunctional wave-absorbing particles are evenly dispersed in the matrix, stirred evenly to obtain a viscous and uniform liquid, vacuum treated for 20 minutes to remove the entrained air, poured into a mold and cured at 25°C for 48 hours to obtain a multifunctional coating material. The matrix used is a mixture of epoxy resin E51 and D230 in a ratio of 5:1. The mass fraction of the multifunctional wave-absorbing particles in the viscous and uniform liquid is 20%.

[0033] like Figure 2 As shown, under the irradiation of visible light, the optical image of the 20wt.% CIP-M-EP coating did not change significantly after corrosion. When exposed to 365nm light, no fluorescence emission was detected. This phenomenon shows that the corrosion state of the CIP-M-EP coating is difficult to be intuitively identified under the irradiation of visible light and 365nm light, thus revealing the hysteresis characteristics of the external manifestation of coating corrosion. However, under the irradiation of 254nm light, the corroded CIP-M-EP coating can emit significant red fluorescence, while the pure EP (0wt.% CIP-M-EP) coating has never been observed to have fluorescence, indicating that the red fluorescence originates from the CIP-M inside the absorbing coating. These results show that the CIP-M-EP coating has a self-warning function, and only under specific wavelength light conditions can the warning signal appear after corrosion, fully demonstrating the high concealment and anti-interference of its self-warning capability.

[0034] Changes in microwave absorption performance of CIP-M-EP coating after immersion in 1% HCl + 6wt.% NaCl solution. The maximum reflection loss (RL) value of CIP-M-EP coating is -35.6dB, which is only 3.45dB lower than that before corrosion, indicating that its microwave absorption performance remains relatively stable.

Claims

1. A method for preparing a multifunctional coating material with self-warning, corrosion resistance, self-repairing and wave absorption characteristics, characterized in that: The method is: Step 1: Preparation of multifunctional wave-absorbing particles: 5-10 g of carbonyl iron is dispersed in 50-200 mL of water and mechanically stirred to obtain solution A; 2-8 g of isocyanate monomer with a functionality of 2 or more, 0.3-2 g of oil-soluble early warning agent, and 1-10 g of self-healing agent are dissolved in a mixed solvent consisting of 2-8 g of oily solvent and 5-12 g of tetraethyl silicate (TEOS) or tetraethyl titanate to obtain solution B; solution B is added to solution A for emulsification, and 5-15 mL of 40 wt.% diselenide diol (HOC3H6Se)2 aqueous solution is added; react in a water bath to remove excess carbonyl iron CIP, and the product is dried to obtain multifunctional wave-absorbing particles; Step 2: Preparation and use of coating: Disperse the multifunctional absorbing particles evenly in the matrix, stir evenly to obtain a viscous and uniform liquid, remove bubbles, pour into a mold and solidify to obtain a multifunctional coating material.

2. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step one, the isocyanate monomer with a functionality of 2 or more is one of polymethylene polyphenyl polyisocyanate (PAPI), diphenylmethane diisocyanate or toluene diisocyanate; the early warning agent is rhodamine B or o-phenanthroline; the self-healing agent is isophorone diisocyanate or toluene diisocyanate; the oily solvent is one of butanone, cyclohexanol, cyclohexanone or isophorone.

3. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 1, the rotation speed of the mechanical stirring is 100-800 rpm / min.

4. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 1, the emulsification speed is 100-1000 rpm / min, and the time is 10-80 minutes.

5. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 1, the temperature of the water bath reaction is 30-90° C. and the reaction time is 5-12 hours.

6. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 1, the drying temperature is 30-60° C. and the drying time is 10-60 minutes.

7. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 2, the substrate is an epoxy rigid substrate or a flexible substrate.

8. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 2, the mass fraction of the multifunctional wave-absorbing particles in the viscous and uniform liquid is 10%-50%.

9. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 2, the degassing is performed by vacuum treatment for 5-80 minutes to remove the entrained air.

10. The method for preparing a multifunctional coating material having self-warning, corrosion resistance, self-repairing and wave absorption characteristics according to claim 1, characterized in that: In step 2, the curing temperature is 20-120° C. and the curing time is 2-50 hours.

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