A biomimetic nacre layer protective coating and a preparation method and application thereof

Abstract

The application discloses a kind of bionic pearl layer protective coating and its preparation method and application.The application is by low viscosity organic resin permeation into the inside of substrate through pore, and the modified inorganic flaky filler with flaky diameter greater than the pore of substrate is blocked in the surface of substrate.The shear force of low viscosity organic resin to flaky filler during downward penetration induces its layer-by-layer parallel stacking, and presents the bionic pearl layer protective coating of " brick mud structure " similar to pearl layer after solidification.The bionic pearl layer protective coating gives full play to the barrier effect of flaky filler, effectively prolongs the diffusion path of corrosion medium such as water, oxygen, etc., and has excellent moisture-proof, anticorrosive, ablation-resistant performance.The method of the application is simple, rapid and low in cost, and is suitable for the preparation of porous material protective coating in engineering materials.

Description

Technical Field

[0001] This invention belongs to the field of protective materials, specifically relating to a biomimetic nacre protective coating, its preparation method, and its application. Background Technology

[0002] Engineering materials, such as concrete and wood, have porous structures, allowing corrosive media to easily penetrate through pores and cracks, leading to corrosion and damage, causing serious economic losses and safety hazards. Currently, coating protection is the most economical and efficient means of protecting porous substrates. However, single organic or inorganic protective coatings suffer from poor protective effects and poor adhesion. Therefore, the inventors have conducted extensive research and development on organic-inorganic composite protective coatings. Among them, the "brick-and-mortar structure" of the organic-inorganic composite biomimetic nacre coating has an ideal barrier protection effect, extending the path of corrosive media to the substrate.

[0003] Biomimetic nacre coatings are generally composed of organic resins and inorganic sheet-like fillers, with the key to their preparation lying in the orderly arrangement and assembly of the sheet-like fillers. Common methods for preparing biomimetic nacre coatings include layer-by-layer assembly, evaporation assembly, electromagnetic field assembly, centrifugal force assembly, and mechanical coating assembly. These methods are cumbersome, require large machinery, and have limited application scenarios. Therefore, it is necessary to develop a simple, efficient, and universally applicable method for preparing biomimetic protective coatings for porous substrates commonly used in engineering. Summary of the Invention

[0004] To address the problems of poor barrier properties in existing protective coatings and the cumbersome and complex preparation process of biomimetic nacre coatings, the primary objective of this invention is to provide a method for preparing a biomimetic nacre protective coating. This method is simple to operate, low in cost, and applicable to various resins, sheet fillers, and porous substrate systems, exhibiting versatility. The prepared biomimetic nacre protective coating fully utilizes the barrier effect of the sheet filler, effectively extending the diffusion path of corrosive media such as water and oxygen, and possesses excellent moisture-proof, corrosion-proof, and ablation-resistant properties. The organic components penetrate into the substrate and solidify, significantly improving coating adhesion. This method can be applied to the preparation of protective coatings for porous materials in engineering materials.

[0005] A second objective of this invention is to provide a biomimetic nacre protective coating prepared by the above-described preparation method.

[0006] A third objective of this invention is to provide the application of the above-mentioned biomimetic nacre protective coating.

[0007] The primary objective of this invention can be achieved through the following technical solutions:

[0008] A method for preparing a biomimetic nacre protective coating includes the following steps:

[0009] (1) Mix 33-36 parts of low-viscosity organic resin, 10-20 parts of modified inorganic flake filler and 44-54 parts of solvent evenly to obtain a composite coating;

[0010] (2) Spray the composite coating from step (1) onto the porous substrate and allow the composite coating to cure to prepare a biomimetic pearl layer protective coating.

[0011] The low-viscosity organic resin is one of low-viscosity epoxy resin or low-viscosity polyurea resin; the modified inorganic sheet filler is at least one of modified mica, modified montmorillonite, and modified kaolin; the solvent is at least two of furfural, benzaldehyde, cyclohexanone, dichloroethane, tributyl acetyl citrate, ethylene glycol ethyl ether acetate, xylene (ortho-, meta-, and para-xylene are all acceptable), and phenethyl ether.

[0012] Preferably, when the low-viscosity organic resin is a low-viscosity epoxy resin, the low-viscosity epoxy resin is mixed and used in a mass ratio of component A to component B of (2-10):1.

[0013] The preparation method of component A includes the following steps:

[0014] a. Mix at least two of the following in any proportion to form a mixture I: tetramethyl silicate, tetraethyl silicate, methyltrimethoxysilane, ethyltriethoxysilane, hexyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane; and thoroughly mix mixture I with glycidoxypropyltrimethoxysilane at a mass ratio of (0.1-1):2 to obtain a silane mixture.

[0015] b. Mix silane mixture, deionized water, hydrochloric acid (36-38% by mass) and ethanol in a mass ratio of 100:(10-30):(1-1.5):150, stir and react at 60-80℃ for 6-12 hours, and remove the solvent by rotary evaporation to obtain epoxy-based silicon clusters.

[0016] c. Mix one of bisphenol A epoxy resin E51 and bisphenol F epoxy resin F44 with epoxy silicone clusters at a mass ratio of 1:(0.5~1.5) to obtain component A;

[0017] The preparation method of component B is as follows: any three substances selected from diethylenetriamine, triethylenetetramine, polyetheramine D400, polyetheramine D2000, polyamide 650, and polyamide 651 are mixed in a mass ratio of 1:0.5:0.5 to obtain component B.

[0018] More preferably, when the low-viscosity organic resin is the low-viscosity polyurea resin, the low-viscosity polyurea resin is mixed and used in a mass ratio of A' component to B' component of 1:(2-8);

[0019] The preparation method of component A' includes the following steps:

[0020] a. Mix any two of the following: tetramethyl silicate, tetraethyl silicate, methyltrimethoxysilane, ethyltriethoxysilane, hexyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane with any one of the following: cyclohexylaminopropyltrimethoxysilane, anilinemethyltriethoxysilane, and n-butylaminopropyltrimethoxysilane, in a mass ratio of (0.1–1):(0.1–1):2 to obtain a silane mixture;

[0021] b. Mix silane mixture, deionized water and ethanol in a mass ratio of 100:(10~30):150, stir and react at 60~80℃ for 6~12h, and remove the solvent by rotary evaporation to obtain secondary aminosilane clusters;

[0022] c. Mix any one of aspartic acid ester resin NH1420 and aspartic acid ester resin NH1220 with secondary aminosilane clusters at a mass ratio of 1:(0.5~1.5) to obtain component A';

[0023] The preparation method of component B' includes the following steps: mixing any three substances from isophorone diisocyanate IPDI, toluene diisocyanate TDI, diphenylmethane diisocyanate MDI, dicyclohexylmethane diisocyanate HMDI, and hexamethylene diisocyanate trimer HDIT in a mass ratio of 0.5:0.5:1 to obtain component B'.

[0024] Preferably, the preparation method of the modified inorganic sheet filler in step (1) includes: mixing water, aminopropyltriethoxysilane and ethanol in a mass ratio of 5:(1~1.5):5 to form a mixture, stirring and hydrolyzing at 25°C for 30~60 min before use, adding 30~50% sheet filler according to the mass of the mixture, stirring at 60~65°C for 4 h, filtering, washing repeatedly three times with a washing solution of water and ethanol in a mass ratio of 1:3, and drying in a vacuum oven at 60~65°C for 24 h to obtain the modified inorganic sheet filler.

[0025] More preferably, the diameter of the sheet-like filler is 10 to 50 μm.

[0026] Preferably, the surface tension of the solvent in step (1) is greater than 30 mN / m.

[0027] Preferably, the stirring rate in step (1) is 200-1000 r / min and the stirring time is 10-30 min.

[0028] Preferably, the viscosity of the composite coating in step (1) is not more than 100 mPa·s and the surface drying time is not less than 6 hours.

[0029] Preferably, the curing conditions in step (2) are 35–50°C.

[0030] Preferably, the porous substrate in step (2) is at least one of wood, concrete, and stainless steel plate.

[0031] Working principle of the invention:

[0032] This invention incorporates a low-viscosity organic resin during the preparation process. This low-viscosity organic resin, based on a traditional resin system, incorporates epoxy-based or secondary amine-based silicon clusters. This reduces the viscosity of the traditional resin system without altering the functional group density, thus facilitating the penetration of the coating onto the substrate. Furthermore, this invention adds a solvent during the preparation process. The selected organic solvent has a surface tension greater than 30 mN / m, generating sufficient additional pressure during penetration to drive the organic resin's penetration and wetting of the substrate.

[0033] The biomimetic nacre protective coating of the present invention is formulated into a coating by low-viscosity organic resin, modified inorganic flake filler and solvent and coated on a porous substrate. During the downward penetration of the low-viscosity organic component, the shear force on the modified inorganic flake filler induces it to stack in parallel layer by layer. After curing, a "brick and mortar structure" biomimetic nacre protective coating is formed, and the low-viscosity organic resin of the coating penetrates into the substrate to form a "rooted" interlocking interface area.

[0034] The second objective of this invention can be achieved through the following technical solutions:

[0035] A biomimetic nacre protective coating is prepared by the above-described preparation method.

[0036] Preferably, the thickness of the biomimetic nacre protective coating is 100–300 μm.

[0037] The third objective of this invention can be achieved through the following technical solutions:

[0038] Application of a biomimetic nacre protective coating.

[0039] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0040] (1) Existing conventional methods for preparing biomimetic nacre coatings, such as layer-by-layer assembly, evaporation assembly, electromagnetic field assembly, centrifugal force assembly, and mechanical coating assembly, are cumbersome to operate, require large machinery and tools, and have limited application scenarios. The permeation-induced preparation method for preparing biomimetic nacre protective coatings described in this invention is simple to operate, inexpensive, and suitable for preparing protective coatings for porous materials in engineering materials;

[0041] (2) The method for preparing a biomimetic nacre protective coating by permeation induction described in this invention has universality. This method is applicable to a variety of porous substrates (such as concrete, wood, and stainless steel plates), a variety of resins (such as epoxy resin and polyurethane resin), and a variety of sheet fillers (mica, montmorillonite, and kaolin).

[0042] (3) The biomimetic nacre protective coating prepared by the present invention through the penetration induction method can also penetrate into the interior of the substrate and solidify in situ to form a “rooted” interlocking layer, thereby greatly improving the adhesion of the coating on the surface of the defective substrate. Attached Figure Description

[0043] Figure 1 An optical photograph of the penetration process of the composite coating on wood described in Example 1;

[0044] Figure 2 This is a SEM cross-sectional view of the epoxy resin / mica biomimetic nacre protective coating described in Example 1;

[0045] Figure 3 This is a SEM cross-sectional view of the epoxy resin / mica composite coating described in Comparative Example 1.

[0046] Figure 4 This is a schematic diagram illustrating the barrier effect of the epoxy resin / mica biomimetic nacre protective coating on corrosive media described in Example 3.

[0047] Figure 5 Electrochemical impedance spectroscopy (EIC) diagrams of the epoxy resin / mica biomimetic nacre protective coating described in Example 3 after immersion in 3.5 wt% NaCl solution for different times;

[0048] Figure 6 The image shows the ablation of the epoxy resin / mica biomimetic nacre protective coating described in Example 1. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments of the present invention, conventional conditions or conditions recommended by the manufacturer shall apply. Raw materials and reagents used without specified manufacturers are all commercially available conventional products. All parts mentioned in the following embodiments refer to parts by weight.

[0050] Example 1

[0051] 1) Preparation of modified filler: 5 parts water, 1 part aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 30 min; 3.3 parts mica were added to the above reaction vessel and heated and stirred at 60°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol, and dried in a vacuum oven at 60°C for 24 h to obtain modified mica.

[0052] 2) Cluster preparation: 2 parts glycidyl etheroxypropyltrimethoxysilane, 1 part tetramethyl silicate, 0.1 part phenyltriethoxysilane, 0.3 parts deionized water, 0.05 parts hydrochloric acid, and 4.7 parts ethanol were thoroughly mixed and stirred at 80°C for 6 hours. The solvent was removed by rotary evaporation to obtain epoxy-based silicon clusters.

[0053] 3) Preparation of composite coating: Component A is obtained by mixing 1 part of bisphenol A epoxy resin E51 and 0.5 parts of epoxy silicone clusters; Component B is obtained by mixing 1 part of diethylenetriamine, 0.5 parts of polyetheramine D2000 and 0.5 parts of polyamide 650; Component B is obtained by mixing 24 parts of component A, 12 parts of component B, 20 parts of modified mica, 22 parts of furfural and 22 parts of cyclohexanone using a high-speed disperser at a speed of 200 r / min for 30 min until homogeneous.

[0054] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the wood and cured in an oven at 35°C for 12 hours to obtain an epoxy resin / mica biomimetic nacre protective coating on the wood.

[0055] The photograph shown in this embodiment illustrates the process of the composite coating penetrating the wood. Figure 1 As shown. The SEM cross-sectional view of the epoxy resin / mica biomimetic nacre protective coating described in this embodiment is shown below. Figure 2 As shown in the image. The epoxy resin / mica biomimetic nacre protective coating described in this embodiment was ablated for 10 seconds. Figure 6 As shown, the spray gun used is a cigar gun, with the nozzle 8cm away from the coating surface.

[0056] Example 2

[0057] 1) Preparation of modified filler: 5 parts water, 1.5 parts aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 40 min; 3.5 parts montmorillonite were added to the above reaction vessel and heated and stirred at 65°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol, and dried in a vacuum oven at 65°C for 24 h to obtain modified montmorillonite.

[0058] 2) Cluster preparation: 2 parts glycidyl etheroxypropyltrimethoxysilane, 1 part tetraethyl silicate, 0.1 part diphenyldiethoxysilane, 0.47 parts deionized water, 0.05 parts hydrochloric acid, and 4.7 parts ethanol were thoroughly mixed and stirred at 80°C for 8 hours. The solvent was removed by rotary evaporation to obtain epoxy-based silicon clusters.

[0059] 3) Preparation of composite coating: Component A is obtained by mixing 1 part of bisphenol A epoxy resin E51 and 1 part of epoxy silicone cluster; Component B is obtained by mixing 1 part of diethylenetriamine, 0.5 part of polyetheramine D2000 and 0.5 part of polyamide 650; Component B is obtained by mixing 30 parts of component A, 6 parts of component B, 15 parts of modified montmorillonite, 25 parts of benzaldehyde and 24 parts of dichloroethane using a high-speed disperser at a speed of 500 r / min for 20 min until homogeneous.

[0060] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the concrete and cured in an oven at 40°C for 12 hours to obtain an epoxy resin / montmorillonite biomimetic nacre protective coating on the concrete.

[0061] Example 3

[0062] 1) Preparation of modified filler: 5 parts water, 1 part aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 50 min; 4.4 parts mica were added to the above reaction vessel and heated and stirred at 60°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol. The mixture was then dried in a vacuum oven at 60°C for 24 h to obtain modified mica.

[0063] 2) Cluster preparation: 2 parts glycidyl etheroxypropyltrimethoxysilane, 0.6 parts methyltrimethoxysilane, 0.4 parts hexyltrimethoxysilane, 0.6 parts deionized water, 0.03 parts hydrochloric acid, and 4.5 parts ethanol were thoroughly mixed and stirred at 70°C for 10 h. The solvent was removed by rotary evaporation to obtain epoxy-based silicon clusters.

[0064] 3) Preparation of composite coating: Component A is obtained by mixing 1 part of bisphenol F epoxy resin F44 and 1 part of epoxy silicone cluster; Component B is obtained by mixing 1 part of triethylenetetramine, 0.5 parts of polyetheramine D400 and 0.5 parts of polyamide 651; Component B is obtained by mixing 32 parts of component A, 4 parts of component B, 10 parts of modified mica, 25 parts of furfural and 25 parts of cyclohexanone using a high-speed disperser at a speed of 1000 r / min for 10 min until homogeneous.

[0065] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the concrete and cured in an oven at 40°C for 12 hours to obtain an epoxy resin / mica biomimetic nacre protective coating on the concrete.

[0066] like Figure 4The above is a schematic diagram illustrating the barrier effect of the epoxy resin / mica biomimetic nacre protective coating on corrosive media in this embodiment. Figure 5 The above figures show the electrochemical impedance spectroscopy (EIS) of the epoxy resin / mica biomimetic nacre protective coating described in this embodiment after immersion in 3.5 wt% NaCl solution for different times.

[0067] Example 4

[0068] 1) Preparation of modified filler: 5 parts water, 1.5 parts aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 60 min; 5.8 parts kaolin were added to the above reaction vessel and heated and stirred at 65°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol. The mixture was then dried in a vacuum oven at 65°C for 24 h to obtain modified kaolin.

[0069] 2) Cluster preparation: 2 parts glycidyl etheroxypropyltrimethoxysilane, 0.4 parts ethyltriethoxysilane, 0.6 parts dimethyldiethoxysilane, 0.9 parts deionized water, 0.03 parts hydrochloric acid, and 4.5 parts ethanol were thoroughly mixed and stirred at 60°C for 12 h. The solvent was removed by rotary evaporation to obtain epoxy-based silicon clusters.

[0070] 3) Preparation of composite coating: Component A is obtained by mixing 1 part of bisphenol F epoxy resin F44 and 1.5 parts of epoxy silicone clusters; Component B is obtained by mixing 1 part of triethylenetetramine, 0.5 parts of polyetheramine D400 and 0.5 parts of polyamide 651; Component B is obtained by mixing 30 parts of component A, 3 parts of component B, 15 parts of modified kaolin, 26 parts of benzaldehyde and 26 parts of dichloroethane using a high-speed disperser at a speed of 500 r / min for 20 min until homogeneous.

[0071] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the rusted steel plate and cured in an oven at 50°C for 12 hours to obtain an epoxy resin / kaolin biomimetic nacre protective coating on the rusted steel plate.

[0072] Example 5

[0073] 1) Preparation of modified filler: 5 parts water, 1 part aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 30 min; 3.3 parts mica were added to the above reaction vessel and heated and stirred at 60°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol, and dried in a vacuum oven at 60°C for 24 h to obtain modified mica.

[0074] 2) Cluster preparation: 2 parts of cyclohexylaminopropyltrimethoxysilane, 1 part of tetramethyl silicate, 0.1 parts of phenyltriethoxysilane, 0.3 parts of deionized water and 4.7 parts of ethanol were thoroughly mixed and stirred at 80°C for 6 h. The solvent was removed by rotary evaporation to obtain secondary aminosilane clusters.

[0075] 3) Preparation of composite coating: Component A is obtained by mixing 1 part aspartic acid ester resin NH1420 and 0.5 parts secondary aminosilicone clusters; Component B is obtained by mixing 0.5 parts isophorone diisocyanate IPDI, 0.5 parts diphenylmethane diisocyanate MDI and 1 part hexamethylene diisocyanate trimer HDIT; Component B is obtained by mixing 12 parts secondary component A, 24 parts component B, 20 parts modified mica, 22 parts acetylated tributyl citrate and 22 parts xylene using a high-speed disperser at a speed of 200 r / min for 30 min until homogeneous.

[0076] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the wood and cured in an oven at 35°C for 12 hours to obtain a polyurethane resin / mica biomimetic nacre protective coating on the wood.

[0077] Example 6

[0078] 1) Preparation of modified filler: 5 parts water, 1.5 parts aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 40 min; 3.5 parts montmorillonite were added to the above reaction vessel and heated and stirred at 65°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol, and dried in a vacuum oven at 65°C for 24 h to obtain modified montmorillonite.

[0079] 2) Cluster preparation: 2 parts n-butylaminopropyltrimethoxysilane, 1 part tetraethyl silicate, 0.1 parts diphenyldiethoxysilane, 0.47 parts deionized water, and 4.7 parts ethanol were thoroughly mixed and stirred at 80°C for 8 hours. The solvent was removed by rotary evaporation to obtain secondary aminosilane clusters.

[0080] 3) Preparation of composite coating: Component A is obtained by mixing 1 part aspartic acid ester resin NH1420 and 1 part secondary aminosilane cluster; Component B is obtained by mixing 0.5 parts isophorone diisocyanate IPDI, 0.5 parts diphenylmethane diisocyanate MDI and 1 part hexamethylene diisocyanate trimer HDIT; Component B is obtained by mixing 7 parts of component A, 28 parts of component B, 15 parts of modified montmorillonite, 23 parts of ethylene glycol ethyl ether acetate and 22 parts of xylene using a high-speed disperser at a speed of 500 r / min for 20 min until homogeneous.

[0081] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the concrete and cured in an oven at 40°C for 12 hours to obtain a polyurethane resin / montmorillonite biomimetic nacre protective coating on the concrete.

[0082] Example 7

[0083] 1) Preparation of modified filler: 5 parts water, 1.5 parts aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 50 min; 4.6 parts kaolin were added to the above reaction vessel and heated and stirred at 65°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol, and dried in a vacuum oven at 65°C for 24 h to obtain modified kaolin.

[0084] 2) Cluster preparation: 2 parts of aniline methyltriethoxysilane, 0.6 parts of methyltrimethoxysilane, 0.4 parts of hexyltrimethoxysilane, 0.6 parts of deionized water and 4.5 parts of ethanol were thoroughly mixed and stirred at 70°C for 10 h. The solvent was removed by rotary evaporation to obtain secondary aminosilane clusters.

[0085] 3) Preparation of composite coating: Component A is obtained by mixing 1 part aspartic acid ester resin NH1220 and 1 part secondary aminosilane clusters; Component B is obtained by mixing 0.5 parts toluene diisocyanate TDI, 0.5 parts dicyclohexylmethane diisocyanate HMDI and 1 part hexamethylene diisocyanate trimer HDIT; Component B is obtained by mixing 5 parts of component A, 30 parts of component B, 15 parts of modified kaolin, 23 parts of acetylacetic acid tributyl ester and 22 parts of phenethyl ether using a high-speed disperser at a speed of 1000 r / min for 10 min until homogeneous.

[0086] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the wood and cured in an oven at 35°C for 12 hours to obtain a polyurethane resin / kaolin biomimetic nacre protective coating on the wood.

[0087] Example 8

[0088] 1) Preparation of modified filler: 5 parts water, 1 part aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 60 min; 5.5 parts mica were added to the above reaction vessel and heated and stirred at 60°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol. The mixture was then dried in a vacuum oven at 60°C for 24 h to obtain modified mica.

[0089] 2) Cluster preparation: 2 parts of anilinemethyltriethoxysilane, 0.4 parts of ethyltriethoxysilane, 0.6 parts of dimethyldiethoxysilane, 0.9 parts of deionized water and 4.5 parts of ethanol were thoroughly mixed and stirred at 60°C for 12 h. The solvent was removed by rotary evaporation to obtain secondary aminosilane clusters.

[0090] 3) Preparation of composite coating: Component A is obtained by mixing 1 part aspartic acid ester resin NH1220 and 1.5 parts secondary amino silicone clusters; Component B is obtained by mixing 0.5 parts toluene diisocyanate TDI, 0.5 parts dicyclohexylmethane diisocyanate HMDI and 1 part hexamethylene diisocyanate trimer HDIT; Component B is obtained by mixing 4 parts of component A, 32 parts of component B, 10 parts of modified mica, 27 parts of ethylene glycol ethyl ether acetate and 27 parts of phenethyl ether using a high-speed disperser at a speed of 1000 r / min for 10 min until homogeneous.

[0091] 4) Preparation of biomimetic nacre protective coating: The composite coating is sprayed onto the rusted steel plate and cured in an oven at 50°C for 12 hours to obtain a polyurethane resin / mica biomimetic nacre protective coating on the rusted steel plate.

[0092] Comparative Example 1

[0093] 1) Preparation of modified filler: 5 parts water, 1 part aminopropyltriethoxysilane and 5 parts ethanol were added to a reaction vessel and stirred and hydrolyzed at 25°C for 1 h; 5.5 parts mica were added to the above reaction vessel and heated and stirred at 60°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol, and dried in a vacuum oven at 60°C for 24 h to obtain modified mica.

[0094] 2) Preparation of biomimetic nacre protective coating: Bisphenol F epoxy resin F44 resin is used as component A. 1 part triethylenetetramine, 0.5 part polyetheramine D400 and 0.5 part polyamide 650 are mixed to obtain component B. 32 parts of component A, 4 parts of component B, 40 parts modified mica, 14 parts furfural and 14 parts cyclohexanone are stirred in a high-speed disperser at a rate of 500 r / min for 20 min until uniform to obtain a composite coating. The composite coating is sprayed onto concrete and cured in an oven at 40℃ for 12 h to obtain an epoxy resin / mica composite coating on the concrete.

[0095] Due to the high filler content, high epoxy resin viscosity, and low solvent content, the initial viscosity of the system is high, resulting in poor penetration into concrete and weak coating adhesion. The organic components have difficulty flowing and exert weak shear forces on the modified sheet filler, insufficient to induce an orderly arrangement of the filler. Consequently, the resulting composite coating exhibits chaotic mica arrangement, numerous defects, and poor barrier properties. The SEM cross-sectional image of the epoxy resin / mica composite coating described in this comparative example is shown below. Figure 3 As shown.

[0096] Comparative Example 2

[0097] 1) Preparation of modified filler: 5 parts water, 1.5 parts aminopropyltriethoxysilane and 5 parts ethanol were added to the reaction vessel and stirred and hydrolyzed at 25°C for 1 h. 5.8 parts kaolin were added to the above reaction vessel and heated and stirred at 65°C for 4 h. After filtration, the mixture was washed three times with a washing solution of 1 part water and 3 parts ethanol. The mixture was then dried in a vacuum oven at 65°C for 24 h to obtain modified kaolin.

[0098] 2) Cluster preparation: 2 parts glycidyl etheroxypropyltrimethoxysilane, 0.4 parts ethyltriethoxysilane, 0.6 parts dimethyldiethoxysilane, 0.3 parts deionized water and 4.5 parts ethanol were thoroughly mixed and stirred at 60°C for 12 h. The solvent was removed by rotary evaporation to obtain epoxy-based silicon clusters.

[0099] 3) Preparation of biomimetic nacre protective coating: Component A was obtained by mixing 1 part bisphenol F epoxy resin F44 and 1.5 parts epoxy-based silicone clusters. Component B was obtained by mixing 1 part triethylenetetramine, 0.5 parts polyetheramine D400, and 0.5 parts polyamide 650. Component B was obtained by mixing 30 parts of component A, 3 parts of component B, 15 parts modified kaolin, 26 parts benzaldehyde, and 26 parts dichloroethane using a high-speed disperser at a rate of 500 r / min for 20 min until homogeneous. The composite coating was then sprayed onto a steel plate. The coating was cured in a 50℃ oven for 12 h to obtain an epoxy resin / mica composite coating on the steel plate.

[0100] Because the surface of the steel plate is flat and dense without pores, the organic components in the coating cannot penetrate into the substrate. Due to the lack of shearing force on the sheet-like filler, the filler is arranged randomly in the coating, and the barrier performance of the coating is inferior to that of the biomimetic composite coating.

[0101] The performance of the biomimetic coatings prepared in Examples 1 to 8 and Comparative Examples 1 to 2 was tested under the following conditions:

[0102] (1) Tested at 25℃ using an NDJ-5S rotational viscometer;

[0103] (2) At 25°C, cut the substrate coated with the coating and measure the penetration depth from the cross section;

[0104] (3) At 25°C, the coated substrate was immersed in water for 72 hours and the overall water absorption rate was measured.

[0105] (4) Refer to GB / T 5210-2006;

[0106] (5) Refer to GB / T 1728-2020.

[0107] Table 1 below shows the performance test graphs of the biomimetic coatings prepared in Examples 1 to 8 and Comparative Examples 1 to 2.

[0108]

[0109] As can be seen from Examples 1 to 8 and Comparative Examples 1 to 2, the composite coatings prepared in Examples 1 to 8 of this invention have a viscosity not exceeding 100 mPa·s, a surface drying time greater than 6 hours, and the organic resin can fully penetrate the porous substrate to a depth of 1–4 mm. During penetration, the shear force on the sheet-like fillers induces their orderly stacking parallel to the substrate layer by layer. The composite coating prepared in Comparative Example 1 has a high viscosity, poor penetration on the porous substrate, and the sheet-like fillers are disordered. The composite coating prepared in Comparative Example 2 cannot penetrate the non-porous substrate, and the sheet-like fillers cannot assemble into an orderly arrangement. The biomimetic nacre protective coatings prepared in Examples 1 to 8 have a water absorption rate of less than 5% after 72 hours and an adhesion greater than 5 MPa, both superior to the comparative examples.

[0110] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a biomimetic nacre protective coating, characterized in that, Includes the following steps: (1) Mix 33-36 parts by weight of low-viscosity organic resin, 10-20 parts by weight of modified inorganic flake filler and 44-54 parts by weight of solvent evenly to obtain a composite coating; (2) Spray the composite coating from step (1) onto the porous substrate and allow the composite coating to cure to prepare a biomimetic pearl layer protective coating. The low-viscosity organic resin is one of low-viscosity epoxy resin or low-viscosity polyurea resin; the modified inorganic sheet filler is at least one of modified mica, modified montmorillonite, and modified kaolin; the solvent is at least two of furfural, benzaldehyde, cyclohexanone, dichloroethane, tributyl acetylacetonate, ethylene glycol ethyl ether acetate, xylene, and phenethyl ether. When the low-viscosity organic resin is a low-viscosity epoxy resin, the low-viscosity epoxy resin is mixed and used in a mass ratio of component A to component B of (2~10):

1. The preparation method of component A includes the following steps: a. Mix at least two of the following in any proportion to form a mixture I: tetramethyl silicate, tetraethyl silicate, methyltrimethoxysilane, ethyltriethoxysilane, hexyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane; and thoroughly mix mixture I with glycidoxypropyltrimethoxysilane at a mass ratio of (0.1~1):2 to obtain a silane mixture. b. Mix silane mixture, deionized water, hydrochloric acid (36-38% by mass) and ethanol in a mass ratio of 100:(10-30):(1-1.5):150, stir and react at 60-80℃ for 6-12 h, and remove the solvent by rotary evaporation to obtain epoxy-based silicon clusters. c. Mix one of the following resins, bisphenol A epoxy resin E51 and bisphenol F epoxy resin F44, with epoxy-based silicone clusters at a mass ratio of 1:(0.5~1.5) to obtain component A; The preparation method of component B is as follows: any three substances selected from diethylenetriamine, triethylenetetramine, polyetheramine D400, polyetheramine D2000, polyamide 650, and polyamide 651 are mixed in a mass ratio of 1:0.5:0.5 to obtain component B; When the low-viscosity organic resin is a low-viscosity polyurea resin, the low-viscosity polyurea resin is used in a mixture of component A' and component B' in a mass ratio of 1:(2~8); The preparation method of component A' includes the following steps: a. Mix any two of the following: tetramethyl silicate, tetraethyl silicate, methyltrimethoxysilane, ethyltriethoxysilane, hexyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, and diphenyldiethoxysilane with any one of the following: cyclohexylaminopropyltrimethoxysilane, anilinemethyltriethoxysilane, and n-butylaminopropyltrimethoxysilane, in a mass ratio of (0.1~1):(0.1~1):2 to obtain a silane mixture. b. Mix silane mixture, deionized water and ethanol in a mass ratio of 100:(10~30):150, stir and react at 60~80℃ for 6~12 h, and remove the solvent by rotary evaporation to obtain secondary aminosilane clusters. c. Mix any one of aspartic acid ester resin NH1420 and aspartic acid ester resin NH1220 with secondary aminosilane clusters at a mass ratio of 1:(0.5~1.5) to obtain component A'; The preparation method of component B' includes the following steps: mixing any three substances from isophorone diisocyanate IPDI, toluene diisocyanate TDI, diphenylmethane diisocyanate MDI, dicyclohexylmethane diisocyanate HMDI, and hexamethylene diisocyanate trimer HDIT in a mass ratio of 0.5:0.5:1 to obtain component B'.

2. The method for preparing the biomimetic nacre protective coating according to claim 1, characterized in that, The preparation method of the modified inorganic sheet packing in step (1) includes: mixing water, aminopropyltriethoxysilane and ethanol in a mass ratio of 5:(1~1.5):5 to form a mixed solution, stirring and hydrolyzing at 25°C for 30~60 min before use, adding 30~50% sheet packing according to the mass of the mixed solution, stirring at 60~65°C for 4 h, filtering, washing repeatedly three times with a washing solution of water and ethanol in a mass ratio of 1:3, and drying in a vacuum oven at 60~65°C for 24 h to obtain the modified inorganic sheet packing.

3. The method for preparing the biomimetic nacre protective coating according to claim 2, characterized in that, The diameter of the sheet-like filler is 10~50 μm.

4. The method for preparing the biomimetic nacre protective coating according to claim 1, characterized in that, The surface tension of the solvent in step (1) is greater than 30 mN / m.

5. The method for preparing the biomimetic nacre protective coating according to claim 1, characterized in that, The viscosity of the composite coating described in step (1) shall not exceed 100 mPa·s, and the surface drying time shall not be less than 6 h.

6. A biomimetic nacre protective coating, characterized in that, It is prepared according to any one of claims 1 to 5.

7. The biomimetic nacre protective coating according to claim 6, characterized in that, The thickness of the biomimetic nacre protective coating is 100~300 μm.

8. An application of a biomimetic nacre protective coating according to any one of claims 6 or 7.

Images