A high-solids protective coating suitable for stainless steel and magnesium alloys with a temperature resistance of 800℃ and its preparation method.

Abstract

This invention relates to a high-solids protective coating suitable for stainless steel and magnesium alloys, resistant to 800℃, comprising component A and component B; wherein component A comprises, by weight parts: methylphenyl silicone resin, 30-40 parts; E51 epoxy resin, 15-20 parts; high-temperature pigment, 15-20 parts; nano-silica, 8-12 parts; modified phosphate, 10-15 parts; mica powder, 6-10 parts; additives, 2.5-3 parts; solvent, a mixture of xylene and n-butanol, 8- 10 parts; wherein component B includes the following components by mass: alicyclic amine curing agent, 45-60 parts; modified alicyclic amine curing agent, 20-30 parts; solvent, a mixture of xylene and n-butanol, 15-25 parts. The preparation method includes the following steps: step S1, preparing component A; step S2, preparing component B; step S3, mixing component A and component B according to a designed ratio, and finally coating and curing to form a film. The advantages of this invention are high adhesion, good corrosion resistance and high temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of high-temperature protective coating technology, and in particular to a high-solids protective coating suitable for stainless steel and magnesium alloys that can withstand 800℃ and its preparation method. Background Technology

[0002] Stainless steel and magnesium alloys are widely used in aerospace, rail transportation, electronics and communications, and high-end equipment manufacturing. Electrochemical corrosion is a problem that both stainless steel and magnesium alloys face during use. Stainless steel is particularly susceptible to electrochemical corrosion at high temperatures. The oxide film on the surface of stainless steel breaks down, creating localized defects. These defects form an anode, while intact areas outside the defects become cathodes, leading to oxygen reduction reactions that significantly damage the stainless steel's structure. Magnesium alloys are chemically reactive and have extremely low standard electrode potentials, making them highly prone to electrochemical corrosion, especially in high-temperature, high-humidity, or salt spray environments, where corrosion problems are particularly pronounced.

[0003] Currently, polyurethane anti-corrosion coating beds are generally used to address the corrosion problems of stainless steel and magnesium alloys. However, existing polyurethane anti-corrosion coatings cannot simultaneously solve the following problems: Adhesion issues: The dense oxide film on the surface of stainless steel and magnesium alloys, along with their high reactivity, makes it difficult for ordinary coatings to achieve long-lasting and strong adhesion, especially after experiencing thermal cycling, the coating is prone to peeling off.

[0004] Corrosion resistance issues: During use, the coating faces a significant challenge due to insufficient corrosion resistance as corrosive media such as water, oxygen, and chloride ions penetrate the surface.

[0005] High temperature resistance issues: Components such as engine peripheral parts and electronic device heat sink housings operate in high-temperature environments, but the coatings are prone to damage under prolonged high-temperature conditions.

[0006] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention discloses a high-solids protective coating suitable for stainless steel and magnesium alloys that can withstand temperatures up to 800°C, and its preparation method.

[0008] A high-solids protective coating suitable for stainless steel and magnesium alloys, resistant to 800℃, characterized in that: Includes component A and component B; Component A includes components counted by mass parts: Methylphenyl silicone resin, 30-40 parts; E51 epoxy resin, 15-20 parts; High-temperature pigment, 15-20 parts; Nano-silica, 8-12 parts; Modified phosphate, 10-15 parts; Mica powder, 6-10 parts; Additives, 2.5-3 parts; Solvent: a mixture of xylene and n-butanol, 8-10 parts; Component B includes components counted by mass parts: Alicyclic amine curing agent, 45-60 parts; Modified fatty amine curing agent, 20-30 parts; Solvent: a mixture of xylene and n-butanol, 15-25 parts.

[0009] Furthermore, the nano-silica includes nano-silica with a melting point of 550°C and nano-silica with a melting point of 650°C.

[0010] Furthermore, the mass ratio of the 550°C nano-silica to the 650°C nano-silica ranges from 2 to 3:1.

[0011] Furthermore, the modified phosphate is a mixture of lanthanum-modified phosphate and aluminum strontium polyphosphate, wherein the mass ratio of lanthanum-modified phosphate to aluminum strontium polyphosphate is 2~3:1.

[0012] Furthermore, the additives include defoamers, wetting agents, anti-settling agents, and adhesion promoters.

[0013] Furthermore, the defoamer content is 0.2-0.3 parts, the wetting agent content is 0.4-0.5 parts, the anti-settling agent content is 0.9-1.0 parts, and the adhesion promoter is ADP alkyl phosphate, with a content of 1.0-1.2 parts.

[0014] Furthermore, the alicyclic amine curing agent is Gas Chemical 2280 or Meidong MD22280L, and the modified alicyclic amine curing agent is Gas Chemical 2636.

[0015] A method for preparing a high-solids protective coating suitable for stainless steel and magnesium alloys that can withstand temperatures up to 800°C includes the following steps: Step S1, prepare component A: The first step involves adding methylphenyl silicone resin, E51 epoxy resin, and additives into a reaction vessel and stirring. The second step involves adding solvent (80% of the total volume), high-temperature pigment, nano-silica, modified phosphate, and mica powder to the reactor while stirring. The third step involves the rapid dispersion of the reaction products. The fourth step is to grind the obtained slurry to ≤50μm; The fifth step is to add the remaining 20% ​​of the solvent and continue stirring. The sixth step is to filter to obtain component A; Step S2, prepare component B: The first step is to add the solvent into the reaction vessel and stir it evenly; The second step involves adding alicyclic amine curing agent and modified aliphatic amine curing agent sequentially into the reactor while stirring, and stirring at medium speed until homogeneous. The third step involves filtration to obtain component B. Step S3: Mix component A and component B according to the specified ratio, stir evenly, and then mature for 15-25 minutes. After that, apply the mixture to the alloy surface that needs protection and cure it into a film at room temperature for 8-10 hours.

[0016] Furthermore, in the first step of step S1, the stirring speed is 800 r / min, and the stirring time ranges from 15 to 25 min; In the third step of step S1, the dispersion speed is 1000 r / min and the dispersion time is 20~30 min; In the fourth step of step S1, the grinding temperature is controlled at ≤55℃, zirconia beads are used for grinding, the particle size of the zirconia beads is 0.8~1.2mm, and the grinding linear speed is ≥10m / s; In the fifth step of step S1, the medium-speed stirring speed is 800 r / min, and the stirring time is 15~25 min; In the sixth step of step S1, the filter mesh size is 120 mesh.

[0017] Furthermore, in the second step of step S2, the medium-speed stirring speed is 800 r / min, and the stirring time is 20~30 min; In the third step of step S2, the filter mesh size is 100 mesh.

[0018] The advantages of this invention are: 1. A combination of alicyclic amine curing agent and modified alicyclic amine curing agent is used to achieve chemical cross-linking with organosilicon resin and epoxy resin, forming a stable and dense Si-OC bond network. It combines the heat resistance of organosilicon with the adhesion of epoxy resin, significantly improving the initial adhesion of the coating on stainless steel and magnesium alloy and the wet adhesion after cold and heat cycling or boiling. The gradient curing process solves the adhesion problem caused by thermal expansion, thus solving the core pain point of easy peeling of high temperature resistant coatings.

[0019] 2. Modified phosphates are used, including the rare earth element lanthanum (La). 3+ It forms a stable complex with phosphate ions and can still release corrosion-inhibiting ions at 800℃, exhibiting better salt spray resistance than traditional zinc phosphate.

[0020] 3. Using nano-silica with different melting points, meter-sized silica fills the micropores in situ, so that the VOC content remains <250g / L even when the volume solid content reaches 80 parts; high-temperature sintering of nano-silica with different melting points further improves the adhesion of the paint film and gives the coating excellent heat resistance.

[0021] 4. The VOC content of each component is much lower than that of traditional high-temperature coating products. The production, storage and application of the coating of this application are safer and meet the requirements of green manufacturing and sustainable development. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the steps involved in creating a high-solids protective coating suitable for stainless steel and magnesium alloys that can withstand temperatures up to 800°C.

[0023] Figure 2 This is an SEM image of the coating cross-section. Detailed Implementation

[0024] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below. Example 1:

[0025] A high-solids protective coating suitable for stainless steel and magnesium alloys, resistant to 800°C, comprising component A and component B.

[0026] Component A includes components listed in parts by mass: Methylphenyl silicone resin, 30 parts.

[0027] E51 epoxy resin, 15 parts.

[0028] High-temperature pigment, 15 parts.

[0029] Nano silica, 9 parts. This includes 6 parts of nano silica with a melting point of 550℃ and 3 parts of nano silica with a melting point of 650℃.

[0030] A mixture of modified phosphate, lanthanum-modified phosphate, and aluminum strontium polyphosphate, 9 parts. Of which, lanthanum-modified phosphate comprises 6 parts and aluminum strontium polyphosphate comprises 3 parts.

[0031] Mica powder, 7 parts; Additives, 3 parts. Specifically, BYK-066 defoamer 0.3 parts, BYK-378 wetting agent 0.5 parts, polyamide wax paste YH-9110 anti-settling agent 1.0 part, and adhesion promoter is ADP alkyl phosphate 1.2 parts.

[0032] Solvent: a mixture of xylene and n-butanol, 10 parts.

[0033] Component B includes components counted by mass parts: The cycloaliphatic amine curing agent is Gas Chemical 2280, 45 parts.

[0034] The modified fatty amine curing agent is Gas Chemical 2636, 20 parts.

[0035] Solvent: a mixture of xylene and n-butanol, 15 parts.

[0036] A method for preparing a high-solids protective coating suitable for stainless steel and magnesium alloys that can withstand temperatures up to 800°C includes the following steps: Step S1, prepare component A: The first step involves adding methylphenyl silicone resin, E51 epoxy resin, and additives into a reaction vessel and stirring at a speed of 800 r / min for a duration of 15 min.

[0037] The second step involves adding solvent (80% of the total volume), high-temperature pigments, nano-silica, modified phosphates, and mica powder to the reactor while stirring.

[0038] The third step involves high-speed dispersion of the reaction product at a speed of 1000 r / min for 20-30 min.

[0039] The fourth step is to grind the obtained slurry to ≤50μm, with the grinding temperature controlled at ≤55℃, using zirconia beads with a particle size range of 0.8~1.2mm and a grinding linear speed ≥10m / s.

[0040] The fifth step is to add the remaining 20% ​​of the solvent and continue stirring at a medium speed of 800 rpm for 15 minutes.

[0041] The sixth step is to filter to obtain component A, with a filtration mesh size of 120 mesh.

[0042] Step S2, prepare component B: The first step is to add the solvent into the reaction vessel and stir it evenly.

[0043] The second step involves adding alicyclic amine curing agent and modified aliphatic amine curing agent sequentially into the reactor while stirring. The mixture is stirred at a medium speed of 800 r / min for 20 min.

[0044] The third step is to filter to obtain component B, with a filter mesh size of 100 mesh.

[0045] Step S3: Mix component A and component B according to the specified ratio, stir evenly, then mature for 15 minutes, and then coat the alloy surface that needs protection. Let it cure into a film at room temperature for 8 hours.

[0046] Finally, samples were taken for testing. Example 2:

[0047] A high-solids protective coating suitable for stainless steel and magnesium alloys, resistant to 800°C, comprising component A and component B.

[0048] Component A includes components listed in parts by mass: Methylphenyl silicone resin, 33 parts.

[0049] E51 epoxy resin, 17 parts.

[0050] High-temperature pigment, 16 parts.

[0051] Nano silica, 9 parts. This includes 6 parts of nano silica with a melting point of 550℃ and 3 parts of nano silica with a melting point of 650℃.

[0052] A mixture of modified phosphate, lanthanum-modified phosphate, and aluminum strontium polyphosphate, 12 parts. Of which, lanthanum-modified phosphate comprises 8 parts and aluminum strontium polyphosphate comprises 4 parts.

[0053] Mica powder, 8 parts; Additives, 3 parts. Specifically, BYK-066 defoamer 0.3 parts, BYK-378 wetting agent 0.5 parts, polyamide wax paste YH-9110 anti-settling agent 1.0 part, and adhesion promoter is ADP alkyl phosphate 1.2 parts.

[0054] Solvent: a mixture of xylene and n-butanol, 10 parts.

[0055] Component B includes components counted by mass parts: The cycloaliphatic amine curing agent is Gas Chemical 2280, 50 parts.

[0056] The modified fatty amine curing agent is Gas Chemical 2636, 25 parts.

[0057] Solvent: a mixture of xylene and n-butanol, 25 parts.

[0058] Coating preparation methods, such as Figure 1 As shown, it includes the following steps: The first step involves adding methylphenyl silicone resin, E51 epoxy resin, and additives into a reaction vessel and stirring at a speed of 800 r / min for a duration of 15 min.

[0059] The second step involves adding solvent (80% of the total volume), high-temperature pigments, nano-silica, modified phosphates, and mica powder to the reactor while stirring.

[0060] The third step involves high-speed dispersion of the reaction product at a speed of 1000 r / min for 30 min.

[0061] The fourth step is to grind the obtained slurry to ≤50μm, with the grinding temperature controlled at ≤55℃, using zirconia beads with a particle size range of 0.8~1.2mm and a grinding linear speed ≥10m / s.

[0062] The fifth step is to add the remaining 20% ​​of the solvent and continue stirring at a medium speed of 800 rpm for 20 minutes.

[0063] The sixth step is to filter to obtain component A, with a filtration mesh size of 120 mesh.

[0064] Step S2, prepare component B: The first step is to add the solvent into the reaction vessel and stir it evenly.

[0065] The second step involves adding alicyclic amine curing agent and modified aliphatic amine curing agent sequentially into the reactor while stirring. The mixture is stirred at a medium speed of 800 r / min for 20 min.

[0066] The third step is to filter to obtain component B, with a filter mesh size of 100 mesh.

[0067] Step S3: Mix component A and component B according to the specified ratio, stir evenly, then mature for 15 minutes, and then coat the alloy surface that needs protection. Let it cure into a film at room temperature for 8 hours.

[0068] Finally, samples were taken for testing. Example 3:

[0069] A high-solids protective coating suitable for stainless steel and magnesium alloys, resistant to 800°C, comprising component A and component B.

[0070] Component A includes components listed in parts by mass: Methylphenyl silicone resin, 40 parts.

[0071] E51 epoxy resin, 20 parts.

[0072] High-temperature pigment, 20 parts.

[0073] Nano silica, 12 parts. This includes 9 parts of nano silica with a melting point of 550℃ and 3 parts of nano silica with a melting point of 650℃.

[0074] A mixture of modified phosphate, lanthanum-modified phosphate, and aluminum strontium polyphosphate, 12 parts. Of which, 9 parts are lanthanum-modified phosphate and 3 parts are aluminum strontium polyphosphate.

[0075] Mica powder, 10 parts; Additives, 2.5 parts. Specifically, BYK-066 defoamer 0.2 parts, BYK-378 wetting agent 0.5 parts, polyamide wax paste YH-9110 anti-settling agent 1.0 part, and adhesion promoter is ADP alkyl phosphate 0.8 parts.

[0076] Solvent: a mixture of xylene and n-butanol, 10 parts.

[0077] Component B includes components counted by mass parts: The cycloaliphatic amine curing agent is MD22280L from the US East Coast, 60 parts.

[0078] The modified fatty amine curing agent is Gas Chemical 2636, 30 parts.

[0079] Solvent: a mixture of xylene and n-butanol, 25 parts.

[0080] Coating preparation methods, such as Figure 1 As shown, it includes the following steps: The first step involves adding methylphenyl silicone resin, E51 epoxy resin, and additives into a reaction vessel and stirring at a speed of 800 r / min for a duration of 15 min.

[0081] The second step involves adding solvent (80% of the total volume), high-temperature pigments, nano-silica, modified phosphates, and mica powder to the reactor while stirring.

[0082] The third step involves high-speed dispersion of the reaction product at a speed of 1000 r / min for 30 min.

[0083] The fourth step is to grind the obtained slurry to ≤50μm, with the grinding temperature controlled at ≤55℃, using zirconia beads with a particle size range of 0.8~1.2mm and a grinding linear speed ≥10m / s.

[0084] The fifth step is to add the remaining 20% ​​of the solvent and continue stirring at a medium speed of 800 rpm for 30 minutes.

[0085] The sixth step is to filter to obtain component A, with a filtration mesh size of 120 mesh.

[0086] Step S2, prepare component B: The first step is to add the solvent into the reaction vessel and stir it evenly.

[0087] The second step involves adding alicyclic amine curing agent and modified aliphatic amine curing agent sequentially into the reactor while stirring. The mixture is stirred at a medium speed of 800 r / min for 20 min.

[0088] The third step is to filter to obtain component B, with a filter mesh size of 100 mesh.

[0089] Finally, samples were taken for testing.

[0090] Product performance testing: Samples: Product of Example 1, Product of Example 2, Product of Example 3, and commercially available Wanteng silicone resin coating.

[0091] The test results are shown in Table 1.

[0092] Table 1 Coating inspection: Test subject: The coating prepared in Example 1 was applied to stainless steel to form a coating.

[0093] Test results: Figure 2 The image is a SEM image showing the uniform distribution of nano-SiO2 (white particles in the image) in the organosilicon-epoxy matrix (magnified 50,000 times).

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-solids protective coating suitable for stainless steel and magnesium alloys, resistant to 800℃, characterized in that: Includes component A and component B; Component A includes components counted by mass parts: Methylphenyl silicone resin, 30-40 parts; E51 epoxy resin, 15-20 parts; High-temperature pigment, 15-20 parts; Nano-silica, 8-12 parts; Modified phosphate, 10-15 parts; Mica powder, 6-10 parts; Additives, 2.5-3 parts; Solvent: a mixture of xylene and n-butanol, 8-10 parts; Component B includes components counted by mass parts: Alicyclic amine curing agent, 45-60 parts; Modified fatty amine curing agent, 20-30 parts; Solvent: a mixture of xylene and n-butanol, 15-25 parts.

2. The high-solids protective coating for stainless steel and magnesium alloys resistant to 800℃ as described in claim 1, characterized in that: The nano-silica includes nano-silica with a melting point of 550°C and nano-silica with a melting point of 650°C.

3. The high-solids protective coating for stainless steel and magnesium alloys resistant to 800℃ as described in claim 1, characterized in that: The mass ratio of the nano-silica with a melting point of 550℃ to the nano-silica with a melting point of 650℃ is in the range of 2~3:

1.

4. The high-solids protective coating for stainless steel and magnesium alloys resistant to 800℃ as described in claim 1, characterized in that: The modified phosphate is a mixture of lanthanum-modified phosphate and aluminum strontium polyphosphate, with a mass ratio of lanthanum-modified phosphate to aluminum strontium polyphosphate ranging from 2 to 3:

1.

5. A high-solids protective coating suitable for stainless steel and magnesium alloys with a temperature resistance of 800℃, as described in claim 1, is characterized in that: The additives include defoamers, wetting agents, anti-settling agents, and adhesion promoters.

6. A high-solids protective coating for stainless steel and magnesium alloys, resistant to 800℃, as described in claim 6, characterized in that: The defoamer content is 0.2-0.3 parts, the wetting agent content is 0.4-0.5 parts, the anti-settling agent content is 0.9-1.0 parts, and the adhesion promoter is ADP alkyl phosphate, with a content of 1.0-1.2 parts.

7. A high-solids protective coating suitable for stainless steel and magnesium alloys with a temperature resistance of 800℃, as described in claim 1, is characterized in that: The alicyclic amine curing agent is Gas Chemical 2280 or Meidong MD22280L, and the modified alicyclic amine curing agent is Gas Chemical 2636.

8. A method for preparing a high-solids protective coating suitable for stainless steel and magnesium alloys with a temperature resistance of 800°C, as described in any one of claims 1-6, characterized in that, Includes the following steps: Step S1, prepare component A: The first step involves adding methylphenyl silicone resin, E51 epoxy resin, and additives into a reaction vessel and stirring. The second step involves adding solvent (80% of the total volume), high-temperature pigment, nano-silica, modified phosphate, and mica powder to the reactor while stirring. The third step involves the rapid dispersion of the reaction products. The fourth step is to grind the obtained slurry to ≤50μm; The fifth step is to add the remaining 20% ​​of the solvent and continue stirring. The sixth step is to filter to obtain component A; Step S2, prepare component B: The first step is to add the solvent into the reaction vessel and stir it evenly; The second step involves adding alicyclic amine curing agent and modified aliphatic amine curing agent sequentially into the reactor while stirring, and stirring at medium speed until homogeneous. The third step involves filtration to obtain component B. Step S3: Mix component A and component B according to the specified ratio, stir evenly, and then mature for 15-25 minutes. After that, apply the mixture to the alloy surface that needs protection and cure it into a film at room temperature for 8-10 hours.

9. A high-solids protective coating suitable for stainless steel and magnesium alloys with a temperature resistance of 800℃, as described in claim 1, is characterized in that: In the first step of step S1, the stirring speed is 800 r / min and the stirring time ranges from 15 to 25 min; In the third step of step S1, the dispersion speed is 1000 r / min and the dispersion time is 20~30 min; In the fourth step of step S1, the grinding temperature is controlled at ≤55℃, zirconia beads are used for grinding, the particle size of the zirconia beads is 0.8~1.2mm, and the grinding linear speed is ≥10m / s; In the fifth step of step S1, the medium-speed stirring speed is 800 r / min, and the stirring time is 15~25 min; In the sixth step of step S1, the filter mesh size is 120 mesh.

10. A high-solids protective coating for stainless steel and magnesium alloys, resistant to 800℃, as described in claim 1, characterized in that: In the second step of step S2, the medium-speed stirring speed is 800 r / min, and the stirring time is 20~30 min; In the third step of step S2, the filter mesh size is 100 mesh.

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