A method for the preparation of a multilayer basalt flake filler for enhancing the corrosion resistance of anticorrosive coatings

Abstract

The present application relates to the technical field of anticorrosive coating filler, in particular to a preparation method of multilayer basalt flake filler for enhancing corrosion resistance of anticorrosive coating. The present application induces microscale monolayer basalt flake self-assembly to form a multilayer stacking structure through surface tension effect of liquid volume shrinkage during liquid evaporation, then fixes the multilayer structure by premixing with paint and solidification to form a coating filler with multilayer structure, and finally blends with the coating to enhance the corrosion resistance of anticorrosive coating. The assembly structure forms ion channels between the layers, which can effectively extend the ion penetration path and enhance the labyrinth effect, that is, capture corrosion ions through the ion channels between the layers, thereby slowing down the rate of corrosion ions penetrating the coating, and achieving the purpose of enhancing the corrosion resistance of the coating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of anticorrosive coating fillers, and particularly relates to a preparation method of a multilayer basalt flake filler for enhancing the corrosion resistance of an anticorrosive coating. BACKGROUND

[0002] Metal materials are prone to corrosion in marine environments, especially under high-salt and high-humidity conditions. Traditional organic coatings can delay corrosion to some extent, but their corrosion resistance and mechanical properties are difficult to meet the needs of long-term service. To improve the protective ability of the coating, inorganic fillers are often introduced to enhance the shielding performance of the coating against corrosion ions. The "labyrinth effect" of two-dimensional sheet fillers can prolong the penetration path of corrosion ions, thereby improving the corrosion resistance of the coating.

[0003] Currently, the two-dimensional fillers commonly used in anticorrosive coatings include graphene and boron nitride, which have excellent barrier properties and chemical stability, but are difficult to be applied on a large scale due to high preparation cost and poor dispersibility. Basalt, as a type of volcanic rock, has been widely used in construction and engineering due to its excellent mechanical and chemical stability. Traditional basalt fillers are in the form of basalt fibers, which have been extensively studied. Recently, a new type of two-dimensional directional growth basalt material, basalt flake, has been developed in China. Basalt flake, as a low-cost and high-mechanical two-dimensional filler, has been proven to significantly improve the permeation resistance and corrosion resistance of the coating. However, existing technologies mainly use physical blending or simple chemical modification to disperse basalt flakes randomly in the coating, but the distribution and orientation of the fillers are difficult to accurately control, which hinders the full play of the "labyrinth effect" of the fillers in slowing down the penetration of corrosion ions through the coating. In addition, the critical addition amount of the fillers is essentially a parameter that indirectly reflects the distribution state of the filler particles in the internal structure of the coating. The addition amount will directly affect the porosity and interfacial bonding strength of the coating. If the critical value is exceeded, a large number of defects will be generated in the internal structure of the coating, leading to a decrease in the mechanical properties of the coating and affecting the overall performance and service life of the coating.

[0004] Therefore, it is a technical problem to be solved in the field of anticorrosive coatings to accurately control the internal structure of basalt flakes in anticorrosive coatings to strengthen the "labyrinth effect" of two-dimensional sheet fillers and further enhance the corrosion resistance of the coating, break through the corrosion resistance barrier of traditional anticorrosive coatings, and ensure that the introduction of multilayers does not increase the defects in the coating. SUMMARY

[0005] The purpose of the present application is to provide a preparation method of a multilayer basalt flake filler for enhancing the corrosion resistance of an anticorrosive coating, which forms a multilayer superposition structure by inducing microscale self-assembly of single-layer basalt flakes based on surface tension during liquid evaporation shrinkage, and then coats and cures the assembled basalt flakes with resin, thereby achieving the technical effect of further enhancing the corrosion resistance of an anticorrosive coating by regulating the texture structure of two-dimensional sheet materials in the coating, improving the corrosion ion capture ability, and delaying the corrosion ion transmission rate on the basis of traditional coatings with uniform dispersion of two-dimensional sheet fillers.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0007] The present application provides a preparation method of a multilayer basalt flake filler for enhancing the corrosion resistance of an anticorrosive coating, which comprises the following steps:

[0008] 1) Disperse microscale basalt flakes in a solvent to obtain a mixture, and then coat the mixture on the surface of a heat-conducting substrate;

[0009] 2) Heat the heat-conducting substrate to transfer heat to the surface of the mixture, evaporate the solvent, add an equal amount of solvent as in step 1) again, heat the heat-conducting substrate to transfer heat to the surface of the mixture, evaporate the solvent, and repeat the above operation at least 5 times to obtain multilayer assembled microscale basalt flakes;

[0010] 3) Mix resin with the multilayer assembled basalt flakes obtained in step 2) to obtain a mixture, and then cure it to obtain a multilayer basalt flake filler.

[0011] In the above technical scheme, further, in step 1), the mass fraction of basalt flakes in the mixture is 2-6 kg / L.

[0012] In the above technical scheme, further, in step 1), the solvent includes water or a mixture of water and one of ethanol and ethylene glycol.

[0013] In the above technical scheme, further, in step 1), the material of the heat-conducting substrate is a material that can directly or indirectly transfer heat, including one of glass, steel plate, and copper plate.

[0014] In the above technical scheme, further, in step 2), the heating temperature is 80-120 DEG C.

[0015] In the above technical scheme, further, in step 3), the resin includes one of silicone resin, polyurethane resin, epoxy resin, and polyester resin.

[0016] Further, in the step 3), the mass fraction of the resin in the mixture is 40%-60%.

[0017] In another aspect of the present application, the application provides the use of the multilayer basalt flake filler prepared by the above method in the preparation of anticorrosive coating.

[0018] The present application has the following advantages:

[0019] (1) Compared with the traditional uniform distribution blending method of single-layer basalt flake filler in anticorrosive coating, the present application applies the evaporation self-assembly technology to the self-assembly of multilayer basalt flake, and further applies the coating pre-coating processing technology, to invent a new preparation method of multilayer basalt flake filler, and apply it to enhance the corrosion resistance of anticorrosive coating.

[0020] (2) Compared with the traditional uniform distribution of single-layer basalt flake in the anticorrosive coating, the present application introduces the prepared multilayer structure basalt flake filler to enhance the ion capture ability of the filler in the anticorrosive coating, and further enhance the "labyrinth effect" (the labyrinth effect refers to the phenomenon that the filler or special structure forms a tortuous physical barrier in the coating or composite material, effectively prolonging the penetration path of corrosive medium, gas or liquid), prolonging the penetration path of corrosive medium, and significantly improving the shielding performance of the coating.

[0021] (3) Compared with the mechanical property enhancement effect of traditional single-layer basalt flake filler on anticorrosive coating, the assembled multilayer basalt flake filler of the present application forms a new complex texture structure in the resin of the anticorrosive coating, further enhancing the tensile strength and impact resistance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 SEM image of the multilayer basalt flake filler prepared in Example 1;

[0023] Figure 2 Optical microscope image of the PDMS coating containing the multilayer basalt flake filler prepared in Example 1;

[0024] Figure 3 Coating polarization curve (I / E) test of Example 4 and Comparative Example 2, a is Tafel curve, b is impedance diagram;

[0025] Figure 4 Coating Tafel curve of Example 5 and Comparative Example 3;

[0026] Figure 5 Coating stress-strain curve and Young's modulus of Example 4, Comparative Example 1 and Comparative Example 2, a is stress-strain curve, b is Young's modulus;

[0027] Figure 6 Grid test chart for the coating of Example 4 and Comparative Examples 1, 2, a is Comparative Example 1, b is Comparative Example 2, and c is Example 4.

[0028] Figure 7 Impact test chart for the coating of Example 4 and Comparative Examples 1, 2.

[0029] Figure 8 Schematic diagram of the preparation method of the multilayer basalt flake filler. DETAILED DESCRIPTION

[0030] The following description is merely exemplary in nature of the present application, and is not intended to limit the present application in any way. Any simple modification, equivalent change and modification made according to the technical essence of the present application to the above examples all fall within the protection scope of the present application.

[0031] The raw materials used in the following examples are all conventional products that can be purchased on the market.

[0032] Example 1

[0033] I. Preparation method of the multilayer basalt flake filler:

[0034] 1) Disperse 20 g of basalt flake in 5 mL of water to obtain a mixture, and then spread the mixture on the surface of a glass culture dish and place it in the center of a heating table;

[0035] 2) Heat the glass culture dish to 100°C until the water is evaporated, add 5 mL of water again, heat the glass culture dish to 100°C until the water is evaporated, and repeat the above operation 5 times to obtain the multilayer assembled basalt flake;

[0036] 3) Mix 5.5 g of polydimethylsiloxane (PDMS) containing 0.5 g of two-component RTV-2 curing agent with 4.5 g of the multilayer assembled basalt flake obtained in step 2), wherein the mass fraction of PDMS in the mixture is 50% and the mass fraction of the curing agent is 5%, so that the PDMS containing the curing agent completely covers the multilayer assembled basalt flake, and then place it in an oven at 60°C for 7 h to cure, to obtain the multilayer basalt flake filler.

[0037] II. Preparation of PDMS coating containing the multilayer basalt flake filler:

[0038] (1) Mix 1 g of the above multilayer basalt flake filler into 5.5 g of PDMS containing 0.5 g of two-component RTV-2 curing agent, stir at a speed of 500 r / min for 5 minutes, and then vacuumize to obtain a coating prepolymer, wherein 1 g of the multilayer basalt flake filler contains 0.5 g of PDMS, 0.05 g of two-component RTV-2 curing agent and 0.45 g of basalt flake;

[0039] (2) The coating prepolymer obtained in step (1) is poured into a polytetrafluoroethylene mold to control the coating thickness to be 1 mm, and then placed in an oven for heating at 60°C for 7 h to obtain a PDMS coating containing the multilayer basalt flake filler.

[0040] Example 2

[0041] Preparation method of the multilayer basalt flake filler:

[0042] 1) 20 g of basalt flakes are dispersed in 5 mL of a mixed solvent of water and ethanol (volume ratio of water to ethanol is 7:3) to obtain a mixture, and then the mixture is spread on the surface of a glass culture dish and placed in the center of a heating table;

[0043] 2) The glass culture dish is heated at 80°C until the water is evaporated, and then 5 mL of the same solvent as in step 1) is added again. The glass culture dish is heated at 80°C until the solvent is evaporated. The above operation is repeated for 20 times to obtain multilayer assembled basalt flakes;

[0044] 3) 5.5 g of PDMS containing 0.5 g of two-component RTV-2 curing agent is mixed with 4.5 g of the multilayer assembled basalt flakes obtained in step 2), wherein the mass fraction of PDMS in the mixture is 50%, and the mass fraction of the curing agent is 5%. The PDMS containing the curing agent completely covers the multilayer assembled basalt flakes, and then it is placed in an oven for heating at 60°C for 7 h to cure, to obtain a multilayer basalt flake filler.

[0045] Example 3

[0046] Preparation method of the multilayer basalt flake filler:

[0047] 1) 20 g of basalt flakes are dispersed in 5 mL of water to obtain a mixture, and then the mixture is spread on the surface of a glass culture dish and placed in the center of a heating table;

[0048] 2) The glass culture dish is heated at 100°C until the water is evaporated, and then 5 mL of water is added again. The glass culture dish is heated at 100°C until the water is evaporated. The above operation is repeated for 5 times to obtain multilayer assembled basalt flakes;

[0049] 3) 5.5 g of epoxy resin containing 0.5 g of polyamide curing agent is mixed with 4.5 g of the multilayer assembled basalt flakes obtained in step 2), wherein the mass fraction of epoxy resin in the mixture is 50%, and the mass fraction of the curing agent is 5%. The epoxy resin containing the curing agent completely covers the multilayer assembled basalt flakes, and then it is placed in an oven for heating at 60°C for 7 h to cure, to obtain a multilayer basalt flake filler.

[0050] Example 4

[0051] Preparation of polydimethylsiloxane coating containing multi-layer basalt flake filler on the surface of steel plate, the preparation method is specifically:

[0052] (1) 1 g of multi-layer basalt flake filler prepared in Example 1 is mixed into 5.5 g of PDMS containing 0.5 g of two-component RTV-2 curing agent, stirred at a speed of 500 r / min for 5 minutes, and then vacuumized to obtain a coating prepolymer;

[0053] (2) A 50x50x1 mm q235 steel plate is used as a substrate, and before use, it is polished with 500 mesh sandpaper, and then placed in an ethanol solution for ultrasonic treatment for 10 minutes. The coating prepolymer obtained in step (1) is coated on the steel plate by self-leveling, and placed in an oven for curing at 70°C for 24 hours.

[0054] Example 5

[0055] Preparation of epoxy resin coating containing multi-layer basalt flake filler on the surface of steel plate, the preparation method is specifically:

[0056] (1) 1 g of multi-layer basalt flake filler prepared in Example 3 is mixed into 5.5 g of epoxy resin containing 0.5 g of polyamide curing agent, stirred at a speed of 500 r / min for 5 minutes, and then vacuumized to obtain a coating prepolymer;

[0057] (2) A 50x50x1 mm q235 steel plate is used as a substrate, and before use, it is polished with 500 mesh sandpaper, and then placed in an ethanol solution for ultrasonic treatment for 10 minutes. The coating prepolymer obtained in step (1) is coated on the steel plate by self-leveling, and placed in an oven for curing at 70°C for 24 hours.

[0058] Comparative Example 1

[0059] Preparation of polydimethylsiloxane coating on the surface of steel plate, the preparation method is specifically:

[0060] (1) 5 g of polydimethylsiloxane and 0.5 g of two-component RTV-2 curing agent are mixed and stirred for 15 min to obtain a PDMS coating prepolymer;

[0061] (2) A 50x50x1 mm q235 steel plate is used as a substrate, and before use, it is polished with 500 mesh sandpaper, and then placed in an ethanol solution for ultrasonic treatment for 10 minutes. The above PDMS coating prepolymer is coated on the steel plate by self-leveling, and placed in an oven for curing at 70°C for 24 hours.

[0062] Comparative Example 2

[0063] A polydimethylsiloxane coating containing un-assembled basalt flake on the surface of a steel plate was prepared, wherein the content of the basalt flake was consistent with that of Example 4, and the preparation method was specifically as follows:

[0064] (1) 0.45 g of un-assembled basalt flake was added into 5.5 g of polydimethylsiloxane and 0.55 g of two-component RTV-2 curing agent, and after stirring for 15 min, the mixture was uniformly mixed to obtain a coating prepolymer;

[0065] (2) A 50x50x1 mm q235 steel plate was used as a substrate, and before use, the substrate was polished with 500 mesh sandpaper and then placed in an ethanol solution for ultrasonic treatment for 10 min. The above coating prepolymer was coated on the steel plate by self-leveling, and then placed in an oven for curing at 70°C for 24 h.

[0066] Comparative Example 3

[0067] An epoxy resin coating containing un-assembled basalt flake on the surface of a steel plate was prepared, wherein the content of the basalt flake was consistent with that of Example 5, and the preparation method was specifically as follows:

[0068] (1) 0.45 g of un-assembled basalt flake was added into 5.5 g of epoxy resin and 0.55 g of polyamide curing agent, and after stirring for 15 min, the mixture was uniformly mixed to obtain a coating prepolymer;

[0069] (2) A 50x50x1 mm q235 steel plate was used as a substrate, and before use, the substrate was polished with 500 mesh sandpaper and then placed in an ethanol solution for ultrasonic treatment for 10 min. The above coating prepolymer was coated on the steel plate by self-leveling, and then placed in an oven for curing at 70°C for 24 h.

[0070] Result analysis:

[0071] Figure 1 The SEM image of the multilayer basalt flake filler prepared in Example 1 was obtained, and from the image, it can be seen that there are multiple layers of assembled structures wrapped by PDMS in the lower left corner of the cured filler.

[0072] Figure 2 The optical microscope image of the PDMS coating containing the multilayer basalt flake filler prepared in Example 1 was obtained, and from the image, it can be seen that the multilayer basalt flake filler inside the PDMS coating is a multiple layer stacking structure.

[0073] Figure 3For the polarization curve (I / E) test of the coating of Example 4 and Comparative Example 2, a three-electrode method was used for the test, the electrolyte cell solvent was 3.5wt% sodium chloride, the reference electrode was a saturated calomel electrode, and an open circuit potential test was performed before the test started. After the open circuit potential was stable, the polarization curve test was performed. As can be seen from the figure, the coating containing the assembled multi-layer basalt flake filler of Example 4 has a significantly improved corrosion resistance and corrosion rate compared to the coating of Comparative Example 2.

[0074] Figure 4 For the Tafel curve of Example 5 and Comparative Example 3, the corrosion resistance and corrosion rate of the epoxy coating containing the assembled multi-layer basalt flake filler are significantly improved compared to the epoxy coating containing the un-assembled basalt flake filler.

[0075] Figure 5 For the analysis of the tensile properties and Young's modulus of the coatings prepared from Example 4 and Comparative Examples 1 and 2, as shown in Figure 5 a, the breaking strength of the coating sample of Comparative Example 2 is improved compared to the pure PDMS of Comparative Example 1, but the elongation at break is reduced, indicating that the addition of basalt flake enhances the mechanical strength but reduces the flexibility; as shown in Figure 5 b, the Young's modulus shows an upward trend with the increase of the flake content, and the assembled multi-layer basalt flake filler further improves the tensile strength of the material, which is more than three times higher than that of pure PDMS, which indicates that the multi-layer stacked structure can more effectively guide the stress from the matrix to the two-dimensional flake material, thereby inhibiting crack propagation during the tensile loading process, and also helps to relieve stress concentration at the interface between the flake material and the matrix, thereby forming a strong and tough composite material system.

[0076] Figure 6 For the adhesion test analysis of Example 4 and Comparative Examples 1 and 2, the adhesion was analyzed by observing the completeness of the cut area using the grid method. The addition of the assembled multi-layer basalt flake filler enhances the mechanical interlocking of the coating and the substrate, and improves the adhesion of the coating.

[0077] Figure 7 For the impact resistance test analysis of Example 4 and Comparative Examples 1 and 2, the diameter of the steel ball of the impact tester was fixed at 8mm, the impact depth was 2mm, the weight of the hammer was 1kg, and the impact strength was 30 N·m, 40 N·m and 50 N·m, respectively. As shown in the figure, the multi-layer structure of the assembled basalt flake significantly improves the impact resistance of the coating.

[0078] The above examples are only the preferred examples of the present application, and are not intended to limit the embodiments. The protection scope of the present application should be defined by the scope of the claims. Other different forms of changes or variations can also be made on the basis of the above description. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for the preparation of a multilayer basalt flake filler for enhancing the corrosion resistance of anticorrosive coatings, characterized by, The method comprises the following steps: 1) dispersing micro-scale basalt flakes in a solvent to obtain a mixture, and then coating the mixture on a heat-transferring substrate; 2) transferring heat from the heat-transferring substrate to the mixture on the surface to evaporate the solvent, and then adding an equal amount of solvent to the mixture on the surface, and repeating the operation of transferring heat from the heat-transferring substrate to the mixture on the surface to evaporate the solvent at least 5 times to obtain a multi-layer assembled micro-scale basalt flake; 3) mixing resin with the multi-layer assembled basalt flake obtained in step 2) to obtain a mixture, and then curing the mixture to obtain a multi-layer basalt flake filler.

2. The production method according to claim 1, characterized by, In step 1), the mass fraction of the basalt flake in the mixture is 2-6 kg / L.

3. The production method according to claim 1, characterized by, In step 1), the solvent comprises water or a mixture of water and one of ethanol and ethylene glycol.

4. The method of claim 1, wherein, In step 1), the heat-transferring substrate material comprises one of glass, a steel plate and a copper plate.

5. The preparation method according to claim 1, characterized in that, In step 2), the heating temperature is 80-120°C.

6. The method of claim 1, wherein, In step 3), the resin comprises one of silicone resin, polyurethane resin, epoxy resin and polyester resin.

7. The preparation method according to claim 1, characterized in that, In step 3), the mass fraction of the resin in the mixture is 40%-60%.

8. Use of the multi-layer basalt flake filler prepared by the preparation method of any one of claims 1-7 in the preparation of anticorrosive paint.

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