Self-repairing type polyurea protective coating and preparation method thereof

Abstract

The invention relates to the technical field of high polymer material coatings, and particularly discloses a self-repairing type polyurea protective coating and a preparation method thereof. The self-repairing type polyurea protective coating comprises a component A and a component B. The component A comprises the following raw materials in parts by weight: 20-30 parts of polyaspartic acid ester, 5-8 parts of amino organic silicon resin, 1-3 parts of mesoporous silica, 1-3 parts of a self-repairing auxiliary agent and 10-20 parts of a solvent. The component B is polyether modified isocyanate; a three-phase interpenetrating network is formed through amino organic silicon resin-polyaspartic acid ester-polyether modified isocyanate, and the good self-repairing effect of the coating is kept in the high-abrasion environment of an automobile chassis, an automobile frame, a fuel tank and the like.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high polymer material coating, in particular to a self-repairing polyurea protective coating and a preparation method thereof. BACKGROUND

[0002] In the field of material protection, protective coating technology has always been the focus of research. With the continuous development of industry, various equipment and structures are facing more complex and harsh use environments, and protective coating plays a crucial role in prolonging the service life of equipment and improving the safety and stability of structures. Polyurea coating is widely used in the protection of new energy vehicles, engineering machinery and other fields due to its excellent wear resistance, corrosion resistance and flexibility.

[0003] However, traditional polyurea coatings are prone to micro-cracks under long-term stress, leading to gradual degradation of protective performance, especially in high-wear and high-stress environments such as automobile chassis, frames and fuel tanks, the service life of polyurea coatings is significantly reduced.

[0004] Currently, the common method on the market is to regularly inspect and maintain the coating, and when damage to the coating is found, artificial repair material is applied for repair. This method relies on regular manual inspection, and some inaccessible parts may not be able to detect damage in time. There are also multi-layer coating structures that improve protection by stacking different functional layers, but still require external intervention to repair the coating after damage, which cannot effectively protect the base material from environmental erosion. SUMMARY

[0005] In order to improve the protective performance and service life of existing polyurea protective coatings, the application provides a self-repairing polyurea protective coating and a preparation method thereof.

[0006] In a first aspect, the application provides a self-repairing polyurea protective coating, which adopts the following technical solution: A self-repairing polyurea protective coating, comprising A component and B component, the A component comprises the following raw materials by weight: polyaspartate 20-30 parts, amino organosilicon resin 5-8 parts, mesoporous silica 1-3 parts, self-repairing additive 1-3 parts, solvent 10-20 parts; the B component is a polyether modified isocyanate.

[0007] By adopting the technical scheme, in the mixing and cross-linking of the A component and the B component, the isocyanate can react with the amino group in the polyaspartic ester to generate urea bonds with strong hydrogen bonding force, which can improve the impact resistance and wear resistance of the protective coating. The amino silicone resin can improve the weather resistance and interfacial adhesion of the coating, and also endows the polyurea structure with good flexibility, making up for the brittleness caused by the reaction between isocyanate and amino group, and enabling the protective coating to have good flexibility and strength. Meanwhile, the introduction of polyether chain segments into the isocyanate can form a bridge between the polyurea chain segments and the amino silicone resin by using polyether, reduce the phase separation phenomenon between the amino silicone resin and the polyurea chain segments, improve the cross-linking density between the components in the protective coating system, eliminate the difference in interfacial tension, reduce the phenomenon of shrinkage cavity generated after the coating is cured, improve the density and film uniformity of the coating, reduce the erosion of external corrosive media, and improve the self-repairing ability of the coating.

[0008] By forming a three-phase interpenetrating network through the amino silicone resin-polyaspartic ester-polyether modified isocyanate, the deformation ability of the protective coating can be effectively improved, and the further expansion of cracks can be reduced, so that the coating can maintain good self-repairing effect in high-wear environments such as automobile chassis, frame and fuel tank. Meanwhile, the formation of silicon-oxygen covalent bonds between the mesoporous silica and the amino silicone resin provides a stable carrier for the self-repairing additive, slowly releases the repairing agent, and improves the repairing efficiency of the coating.

[0009] Preferably, the polyether in the polyether modified isocyanate is a hydroxyl-terminated polyether, and the isocyanate is a alicyclic isocyanate.

[0010] By adopting the technical scheme, the alicyclic isocyanate can improve the high-temperature resistance of the coating, the reaction is mild, and the weather resistance and corrosion resistance of the coating are improved.

[0011] Preferably, the method for preparing the polyether modified isocyanate comprises the following specific steps: mixing the isocyanate and the hydroxyl-terminated polyether, stirring uniformly, heating to 70-80℃ for reaction, and obtaining the polyether modified isocyanate.

[0012] Preferably, the mass ratio of the isocyanate, triethylenediamine and hydroxyl-terminated polyether is 1:(0.03-0.05):(0.8-1).

[0013] Preferably, the mesoporous silica loaded with the self-repairing additive comprises the following specific steps: Mixing the emulsifier, ammonia water and cyclohexane, stirring uniformly, forming a mixed solution A, mixing the self-repairing additive and water, forming a mixed solution B, adding the mixed solution B to the mixed solution A while stirring, high-speed emulsifying, forming a self-repairing emulsion, adding tetraethyl orthosilicate to the self-repairing emulsion, heating and reacting, centrifuging, washing and separating, drying to obtain the mesoporous silica loaded with the self-repairing additive.

[0014] By adopting the technical scheme, the self-repairing assistant is loaded by mesoporous silica, which can effectively delay the release of the self-repairing assistant, improve the long-acting anti-corrosion performance and self-repairing performance of the coating.

[0015] Preferably, the mass ratio of the emulsifier, ammonia water, cyclohexane, self-repairing assistant and water is (4-5) : (1.5-2) : (5-10) : 1 : (8-12).

[0016] Preferably, the heating temperature is 35-45℃.

[0017] Preferably, the self-repairing assistant comprises an inhibitor and a hydrophobic agent.

[0018] Preferably, the mass ratio of the A component to the B component is 1 : (0.8-1).

[0019] In a second aspect, the application provides a preparation method of the self-repairing polyurea protective coating, which adopts the following technical scheme: The preparation method of the self-repairing polyurea protective coating comprises the following specific steps: mixing polyaspartic acid ester, amino organosilicon resin, mesoporous silica, self-repairing assistant and solvent, heating to 100-110℃ for reaction to obtain an A component, and then mixing the A component and a B component to prepare the self-repairing polyurea protective coating.

[0020] By adopting the technical scheme, under the synergistic effect of the components, the prepared polyurea protective coating has good weather resistance, corrosion resistance and flexibility, reduces the generation and expansion of cracks, has a relatively long service life and good self-repairing performance in high-wear environments such as automobile chassis, frames and fuel tanks.

[0021] In summary, the application has the following beneficial effects 1. Since the application adopts the three-phase interpenetrating network formed by amino organosilicon resin-polyaspartic acid ester-polyether modified isocyanate, the protective coating has good flexibility and strength, reduces the further expansion of cracks, maintains good self-repairing effect of the coating in high-wear environments such as automobile chassis, frames and fuel tanks. The silicon-oxygen covalent bond formed by mesoporous silica and amino organosilicon resin provides a stable carrier for the self-repairing assistant, slowly releases the repairing agent and improves the repair efficiency of the coating.

[0022] 2. In the application, the self-repairing assistant is loaded by mesoporous silica, which can effectively delay the release of the self-repairing assistant, improve the long-acting anti-corrosion performance and self-repairing performance of the coating. DETAILED DESCRIPTION

[0023] The application will be further described in detail below in combination with embodiments.

[0024] All raw materials in the examples can be obtained by market. Example

[0025] Example 1 The present example provides a self-repairing polyurea protective coating, which comprises A component and B component, and the mass ratio of A component to B component is 1:1. The A component comprises the following raw materials by weight: polyaspartic ester 25 kg, amino silicone resin 7 kg, mesoporous silica 2 kg, self-repairing additive 2 kg, and solvent 15 kg. The average pore size of the mesoporous silica is 50 nm, the number average molecular weight of the polyaspartic ester is 800 g / mol, the self-repairing additive is a corrosion inhibitor and a hydrophobic agent in a mass ratio of 1:1, the corrosion inhibitor is benzotriazole, the hydrophobic agent is octadecyl trimethoxysilane, the amino content in the amino silicone resin is 1.2%, the viscosity is 800 cps (25°C), and the solvent is butyl acetate.

[0026] The B component is a polyether modified isocyanate, the polyether is a hydroxyl-terminated polyether 330N, and the isocyanate is dicyclohexylmethane diisocyanate.

[0027] The preparation method of the self-repairing polyurea protective coating comprises the following specific steps: S1: mixing isocyanate, triethylenediamine and hydroxyl-terminated polyether, stirring uniformly, the mass ratio of isocyanate, triethylenediamine and hydroxyl-terminated polyether is 1:0.03:0.8, heating to 75°C for 2h to obtain a polyether modified isocyanate, i.e. the B component.

[0028] S2: mixing polyaspartic ester, amino silicone resin, mesoporous silica, self-repairing additive and solvent, heating to 100°C for 5h to obtain the A component, and then mixing the A component and the B component to obtain the self-repairing polyurea protective coating.

[0029] Example 2 The difference between example 2 and example 1 is that the A component comprises the following raw materials by weight: polyaspartic ester 20 kg, amino silicone resin 8 kg, mesoporous silica 1 kg, self-repairing additive 3 kg, and solvent 10 kg.

[0030] Example 3 The difference between example 3 and example 1 is that the A component comprises the following raw materials by weight: polyaspartic ester 30 kg, amino silicone resin 5 kg, mesoporous silica 3 kg, self-repairing additive 1 kg, and solvent 20 kg.

[0031] Example 4 The difference between Example 4 and Example 1 is that the mass ratio of isocyanate, triethylene diamine and end hydroxyl polyether mixed in the polyether modified isocyanate raw material is 1:0.05:1.

[0032] Example 5 The difference between Example 5 and Example 1 is that the isocyanate in the polyether modified isocyanate raw material is aromatic isocyanate-diphenyl methane diisocyanate.

[0033] Example 6 The difference between Example 6 and Example 1 is that the mesoporous silica is loaded with a self-repairing aid.

[0034] The preparation method of the self-repairing polyurea protective coating comprises the following specific steps: S1: Mix emulsifier OP-10, ammonia, and cyclohexane to form a mixed solution A, mix the self-repairing aid and water to form a mixed solution B, add the mixed solution B to the mixed solution A while stirring, the mass ratio of emulsifier, ammonia, cyclohexane, self-repairing aid, and water is 4:1.5:5:1:8, emulsify at a speed of 700 r / min for 30 min, form a self-repairing emulsion, drop the tetraethyl orthosilicate into the self-repairing emulsion while stirring at a speed of 250 r / min, heat to 35℃ and react for 24 h, centrifuge, wash and separate, dry to obtain mesoporous silica loaded with a self-repairing aid.

[0035] S2: Mix isocyanate, triethylene diamine and end hydroxyl polyether, stir until uniform, the mass ratio of isocyanate, triethylene diamine and end hydroxyl polyether mixed is 1:0.03:0.8, heat to 75℃ and react for 2 h to obtain polyether modified isocyanate, i.e. component B.

[0036] S3: Mix polyaspartic acid ester, amino silicone resin, mesoporous silica loaded with a self-repairing aid, and solvent, heat to 100℃ and react for 5 h to obtain component A, then mix component A and component B to obtain the self-repairing polyurea protective coating.

[0037] Example 7 The difference between Example 7 and Example 6 is that in the preparation of mesoporous silica loaded with a self-repairing aid, the mass ratio of emulsifier, ammonia, cyclohexane, self-repairing aid, and water is 5:2:10:1:12.

[0038] Example 8 Example 8 differs from Example 6 in the preparation method of the self-repairing polyurea protective coating, which comprises the following specific steps: S1: mixing emulsifier OP-10, ammonia water and cyclohexane, stirring uniformly to form a mixed solution A, mixing a self-repairing aid and water to form a mixed solution B, adding the mixed solution B to the mixed solution A while stirring, the mass ratio of the emulsifier, ammonia water, cyclohexane, self-repairing aid and water being 4:1.5:5:1:8, emulsifying at a speed of 700 r / min for 30 min to form a self-repairing emulsion, adding tetraethyl orthosilicate to the self-repairing emulsion while stirring at a speed of 250 r / min, heating to 45℃ and reacting for 24 h, washing and separating after centrifugation, and drying to obtain mesoporous silica loaded with a self-repairing aid.

[0039] S2: mixing isocyanate, triethylenediamine and hydroxyl-terminated polyether, stirring uniformly, the mass ratio of the isocyanate, triethylenediamine and hydroxyl-terminated polyether being 1:0.03:0.8, heating to 75℃ and reacting for 2 h to obtain polyether-modified isocyanate, i.e. component B.

[0040] S3: mixing polyaspartic acid ester, amino silicone resin, mesoporous silica loaded with a self-repairing aid and solvent, heating to 100℃ and reacting for 5 h to obtain component A, and then mixing component A and component B to obtain the self-repairing polyurea protective coating.

[0041] Comparative Example Comparative Example 1 Comparative Example 1 differs from Example 1 in that the B component in the raw materials of the self-repairing polyurea protective coating is isocyanate, and the isocyanate is dicyclohexylmethane diisocyanate.

[0042] The preparation method of the self-repairing polyurea protective coating comprises the following specific steps: S2: mixing polyaspartic acid ester, amino silicone resin, mesoporous silica, self-repairing aid and solvent, heating to 100℃ and reacting for 5 h to obtain component A, and then mixing component A and component B to obtain the self-repairing polyurea protective coating.

[0043] Comparative Example 2 Comparative Example 2 differs from Example 1 in that mesoporous silica is not used in the raw materials of the self-repairing polyurea protective coating.

[0044] Comparative Example 3 Comparative Example 3 differs from Example 1 in that amino silicone resin is not used in the raw materials of the self-repairing polyurea protective coating.

[0045] Performance detection test The self-repairing polyurea protective coating provided by Examples 1-8 and Comparative Examples 1-3 of the present application is subjected to the following performance detection, and the specific detection results are shown in Table 1.

[0046] Detection methods I. Self-healing performance The self-healing polyurea protective coating prepared in this application was subjected to a scratch test. A scratch with a length of 10 mm and a depth of 5 mm was made on the coating. The coating was then immersed in a 5 wt% sodium chloride solution for 56 h and observed under an electron microscope.

[0047] II. Corrosion Resistance Referring to the standard GB / T1763-1979 "Determination of Chemical Resistance of Coating Films", the alkali resistance (10% sodium hydroxide, 56h) and acid resistance (5% hydrochloric acid, 56h) of the self-healing polyurea protective coating prepared in this application were tested.

[0048] III. Mechanical Properties The impact resistance, abrasion resistance and adhesion of the self-healing polyurea protective coating prepared in this application were tested in accordance with the standards of GB / T1732-2020 "Determination of Impact Resistance of Paint Film", GB / T1689-1998 "Determination of Abrasion Resistance of Vulcanized Rubber" and GB / T5210-2006 "Adhesion Test of Paint and Varnish by Pull-Off Method".

[0049] Table 1: Performance Test Results Data Table The performance test results show that, under the synergistic effect of the various components, the polyurea protective coating prepared in this application has good wear resistance, corrosion resistance and flexibility, reduces the generation and propagation of cracks, and maintains good impact resistance.

[0050] A comparison of Example 5 and Example 1 shows that the alicyclic isocyanate used in Example 1 reacts with component A at a lower temperature, which is beneficial for improving the corrosion resistance and repair effect of the coating. A comparison of Comparative Example 1 and Example 1 shows that Comparative Example 1 did not use polyether to modify the isocyanate. Performance testing results show that the coating's impact strength and corrosion resistance decreased, and its self-healing ability was reduced. This further illustrates that introducing polyether segments into the isocyanate increases the crosslinking density between components in the protective coating system, thereby improving the coating's density and corrosion resistance.

[0051] In Examples 6-8, the self-healing agent was loaded onto mesoporous silica. The performance test results showed that the self-healing agent loaded onto mesoporous silica could effectively delay the release of the self-healing agent and improve the long-term corrosion resistance and self-healing performance of the coating.

[0052] Comparing Comparative Examples 2-3 with Example 1, it is evident that Comparative Example 2, which does not use mesoporous silica, and Comparative Example 3, which does not use amino silicone resin, both show a decrease in overall coating performance, as indicated by performance testing. This further demonstrates that the present application utilizes an amino silicone resin-polyaspartic acid ester-polyether-modified isocyanate to form a triple interpenetrating network, effectively improving the deformation capability of the protective coating and maintaining its good self-healing effect. Simultaneously, the formation of silicon-oxygen covalent bonds between mesoporous silica and amino silicone resin provides a stable carrier for the self-healing agent, allowing for the slow release of the repair agent and improving coating repair efficiency.

[0053] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A self-healing polyurea protective coating, characterized in that, It includes component A and component B. Component A includes the following raw materials in parts by weight: 20-30 parts of polyaspartic acid ester, 5-8 parts of amino silicone resin, 1-3 parts of mesoporous silica, 1-3 parts of self-healing agent, and 10-20 parts of solvent; component B is polyether modified isocyanate.

2. The self-healing polyurea protective coating according to claim 1, characterized in that, The polyether-modified isocyanate is a hydroxyl-terminated polyether, and the isocyanate is an alicyclic isocyanate.

3. The self-healing polyurea protective coating according to claim 2, characterized in that, The method for modifying polyether isocyanate includes the following specific steps: mixing isocyanate, triethylenediamine and hydroxyl-terminated polyether, stirring evenly, and heating to 70-80℃ to react, thereby obtaining polyether-modified isocyanate.

4. The self-healing polyurea protective coating according to claim 1, characterized in that, The mass ratio of isocyanate, triethylenediamine and hydroxyl-terminated polyether is 1:(0.03-0.05):(0.8-1).

5. The self-healing polyurea protective coating according to claim 1, characterized in that, The mesoporous silica-supported self-healing agent includes the following specific steps: Emulsifier, ammonia, and cyclohexane are mixed and stirred until homogeneous to form mixture A. Self-healing agent and water are mixed to form mixture B. Mixture B is added to mixture A while stirring. After high-speed emulsification, a self-healing emulsion is formed. Tetraethyl orthosilicate is added dropwise to the self-healing emulsion. The mixture is heated to react, centrifuged, washed and separated, and dried to obtain mesoporous silica loaded with self-healing agent.

6. The self-healing polyurea protective coating according to claim 5, characterized in that, The mass ratio of the emulsifier, ammonia, cyclohexane, self-healing agent, and water is (4-5):(1.5-2):(5-10):1:(8-12).

7. The self-healing polyurea protective coating according to claim 5, characterized in that, The heating temperature is 35-45℃.

8. The self-healing polyurea protective coating according to claim 5, characterized in that, The self-healing aid includes corrosion inhibitors and hydrophobic agents.

9. The self-healing polyurea protective coating according to claim 1, characterized in that, The mass ratio of component A to component B is 1:(0.8-1).

10. A method for preparing a self-healing polyurea protective coating as described in any one of claims 1-9, characterized in that, The specific steps include: mixing polyaspartic acid ester, amino silicone resin, mesoporous silica, self-healing agent and solvent, heating to 100-110℃ to react, obtaining component A, and then mixing component A and component B to obtain a self-healing polyurea protective coating.

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