High-temperature-resistant water-based paint as well as preparation method and use method thereof

Abstract

The invention discloses a high-temperature-resistant water-based coating which comprises the following components in percentage by mass: 5-15% of high-temperature-resistant filler, 25-40% of pigment and filler, 5-12% of binder, 0.1-0.5% of dispersing agent, 1-5% of suspending agent, 2-10% of additive and 40-45% of water. According to the high-temperature-resistant water-based paint disclosed by the invention, the high-temperature-resistant filler is added into a paint system to strengthen the coating and effectively improve the high-temperature resistance of the coating, the completeness and color development capability of the coating under the high-temperature condition are ensured by adding the pigment filler, and the modified organic silicon resin is added as a binder to improve the bonding strength between an abrasive and a matrix; the adhesive force of the coating is effectively improved; the high-temperature resistance of the coating is further improved. The high-temperature-resistant water-based coating disclosed by the invention can tolerate short-time high temperature of 1400 DEG C and long-time thermal cycle of 800 DEG C; the adhesive force is high, and the first-level index is achieved through a gridding method test; the coating is uniformly dispersed, and no spray gun blockage phenomenon occurs in the spraying process; the VOC content is lower than 50g / L, and the coating belongs to an environment-friendly coating.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly to a high-temperature resistant water-based coating, a preparation method thereof, and a usage method thereof. Background Art

[0002] During the production process of centrifugally cast pipes, information such as the model, batch number, and production date of the cast pipes needs to be spray-coded onto the surface of the cast pipes. Since the centrifugally cast pipes also need to go through processes such as high-temperature cooling and heat treatment after centrifugal casting, conventional coatings are prone to phenomena such as peeling, carbonization, and gun clogging during the spray-coding process in a high-temperature environment above 200°C, resulting in blurred spray-coded markings, and further making it difficult to trace the subsequent processes of the cast pipes. In the prior art, the commonly used high-temperature resistant coatings are silicate or ceramic coatings, but both of these coatings have problems such as insufficient adhesion, high cost, and complex spraying processes, and the high-temperature spray-coding quality is not good. Summary of the Invention

[0003] Based on this, in order to solve the above technical problems, the present invention provides an environmentally friendly high-temperature resistant water-based coating with strong adhesion and anti-gun clogging ability, a preparation method thereof, and a usage method thereof.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A high-temperature resistant water-based coating, calculated by mass percentage, includes: 5% - 15% filler A, 25% - 40% filler B, 5% - 12% binder, 0.1% - 0.5% dispersant, 1% - 5% suspending agent, and 40% - 45% dispersion medium; the filler A is a high-temperature resistant filler; the filler B is a pigment filler; the dispersion medium is water.

[0006] Further, the high-temperature resistant filler includes at least one of corundum powder, nano-aluminum oxide, silica powder, and silicon carbide.

[0007] Further, the pigment filler includes at least one of titanium dioxide, zinc oxide, zinc phosphate, barium sulfate, aluminum oxide, aluminum hydroxide, and graphene quantum dots.

[0008] Further, the high-temperature resistant water-based coating further includes 2% - 10% additives, and the additives include at least one of a preservative, an antifoaming agent, an adhesion promoter, and a co-solvent.

[0009] Among them, the preservative can be sodium benzoate, the antifoaming agent can be an organosilicon antifoaming agent, the adhesion promoter can be a bis-aminosilane complex, and the co-solvent can be propylene glycol.

[0010] Further, the binder is a modified silicone resin.

[0011] Further, the modified silicone resin is a high-temperature resistant silicone resin modified with a carboxyl-terminated nitrile rubber for flexible chain segments.

[0012] Further, the dispersant includes at least one of polycarboxylate dispersants, polyurethane dispersants, and acrylic dispersants.

[0013] Further, the suspending agent includes at least one of sodium-based bentonite, lithium-based bentonite, attapulgite, sodium carboxymethyl cellulose, sodium alginate, and xanthan gum.

[0014] In a second aspect, the present application also provides a preparation method, which is applied to the high-temperature resistant water-based coating described above. This preparation method includes the following steps:

[0015] S1. High-speed shear and disperse the binder and the dispersion medium for 10 min to 20 min;

[0016] S2. Add the dispersant and high-speed shear and disperse for 5 min to 15 min;

[0017] S3. Add filler A and filler B and high-speed shear and disperse for 20 min to 40 min;

[0018] S4. Add the suspending agent and high-speed shear and disperse for 10 min to 20 min to obtain the high-temperature resistant water-based coating.

[0019] In a third aspect, the present application also provides a usage method, which is applied to the high-temperature resistant water-based coating described above. The high-temperature resistant water-based coating is used for inkjet marking of centrifugal casting pipes in a high-temperature production environment.

[0020] Further, before use, the high-temperature resistant water-based coating is filtered through an 80-mesh to 240-mesh sieve to remove larger particulate matters, and the viscosity of the filtered coating is adjusted to 10 s to 12 s with a viscosity flow cup by adding water.

[0021] The method of the present invention has the following beneficial effects compared with the prior art:

[0022] The high-temperature resistant water-based coating disclosed by the present invention adds filler A to the coating system to strengthen the coating and effectively improve the high-temperature resistance of the coating, adds filler B to ensure the integrity and color display ability of the coating under high-temperature conditions, and adds modified silicone resin as a binder to improve the bonding strength between the abrasive and the substrate, effectively improving the adhesion of the coating and further enhancing the high-temperature resistance of the coating. The high-temperature resistant water-based coating disclosed by the present invention has excellent high-temperature resistance, can withstand short-term high temperatures of 1400 °C and long-term thermal cycling at 800 °C; has strong adhesion and reaches the first-level index through the cross-cut test; the coating is evenly dispersed and there is no phenomenon of blocking the spray gun during the spraying process; it contains no heavy metals such as lead and chromium, and the VOC content is less than 50 g / L, belonging to an environmentally friendly coating. Moreover, the high-temperature resistant water-based coating disclosed by the present invention effectively reduces the manufacturing cost of the coating, with a cost reduction of more than 30% compared to traditional ceramic coatings. Detailed implementation manners

[0023] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to relevant embodiments. The preferred embodiments of the present invention are given in the embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0025] One of the objectives of the present invention is to disclose a high-temperature resistant water-based coating, which, by mass percentage, may include: 5% - 15% filler A, 25% - 40% filler B, 5% - 12% binder, 0.1% - 0.5% dispersant, 1% - 5% suspending agent, 2% - 10% additives, and 40% - 45% dispersion medium. Filler A may be a high-temperature resistant filler, which is used to enhance the hardness and high-temperature resistance of the coating; filler B may be a pigment filler, which ensures the integrity and color rendering ability of the coating under high-temperature conditions; the binder may be a modified silicone resin, which guarantees the bonding strength between the abrasive and the matrix, and is used to improve the high-temperature resistance and adhesion. The coating system of the present invention conducts a dispersion effect by adding a dispersant, so that the powder particles are dispersed and suspended in the solvent system for a long time, avoiding re-flocculation, thereby achieving the stability of the coating system; by adding a suspending agent, not only the solids are dispersed, but also the solids have the ability to be suspended in the carrier. The additives may include at least one of preservatives, defoamers, adhesion promoters, and cosolvents, ensuring that the coating system has stable performance and the best use effect. The dispersion medium of the present invention is water, which is the dispersion carrier of each component in the coating and belongs to an environmentally friendly solvent.

[0026] The modification process of the modified silicone resin may be to mix the silicone resin and carboxyl-terminated nitrile rubber in a mass ratio of 8 - 10:1, and conduct a grafting reaction at 100°C - 200°C for 3 - 5 hours under nitrogen protection to obtain a high-temperature resistant resin modified with a flexible chain segment. Preferably, the modification process of the modified silicone resin may be to mix the silicone resin and carboxyl-terminated nitrile rubber (CTBN) in a mass ratio of 9:1, and conduct a grafting reaction at 160°C for 4 hours under nitrogen protection to obtain a high-temperature resistant resin modified with a flexible chain segment. Among them, the phenyl content of the silicone resin is preferably 30%.

[0027] Furthermore, the high-temperature resistant filler may be at least one of corundum powder, nano-aluminum oxide, silica powder, and silicon carbide; the pigment filler may be at least one of titanium dioxide, zinc oxide, zinc phosphate, barium sulfate, aluminum oxide, aluminum hydroxide, and graphene quantum dots (CQDS); the dispersant may be at least one of polycarboxylate dispersants, polyurethane dispersants, and acrylic dispersants; the suspending agent may be at least one of sodium-based bentonite, lithium-based bentonite, attapulgite, sodium carboxymethyl cellulose, sodium alginate, and xanthan gum.

[0028] Among them, as a high-temperature resistant filler, alumina needs to be nano-level alumina to play a role in high-temperature resistance.

[0029] The second objective of the present invention is to provide a preparation method, which is applied to the high-temperature resistant water-based coating described in any of the above embodiments. The preparation method may include the following steps:

[0030] S11. Mix silicone resin and carboxyl - terminated nitrile rubber at a mass ratio of 8 - 10:1, and conduct a grafting reaction at 100°C - 200°C for 3 - 5 hours under nitrogen protection to obtain a high - temperature - resistant modified silicone resin with a flexible chain segment modification.

[0031] S12. High - speed shear - disperse 5% - 12% of the modified silicone resin and 40% - 45% of water at room temperature (20 ± 5°C) to ensure that the binder system is fully opened in the dispersion medium. The dispersion speed in this step can be 1800 rpm - 2200 rpm, and the dispersion time can be 10 min - 20 min.

[0032] S13. Add 0.1% - 0.5% of the dispersant to the solution obtained in step S2, and continue high - speed shear - dispersion at room temperature (20 ± 5°C) to improve the dispersibility, solubility, and stability in the solvent system. The dispersion speed in this step can be 1800 rpm - 2200 rpm, and the dispersion time can be 5 min - 15 min.

[0033] S14. Add 5% - 15% of filler A and 25% - 40% of filler B to the solution obtained in step S3, and continue high - speed shear - dispersion at room temperature (20 ± 5°C). In this step, the powder particles are prone to flocculation, and the mixing uniformity of the dispersion system can be improved by increasing the rotation speed and extending the dispersion time. The dispersion speed in this step can be 2300 rpm - 2700 rpm, and the dispersion time can be 20 min - 40 min.

[0034] S15. Add 1% - 5% of the suspending agent and / or 2% - 10% of the auxiliary agent to the solution obtained in step S4, and continue high - speed shear - dispersion at room temperature (20 ± 5°C) to obtain the high - temperature - resistant water - based coating of the present invention. The dispersion speed in this step can be 2300 rpm - 2700 rpm, and the dispersion time can be 10 min - 20 min.

[0035] The third object of the present invention is to provide a usage method, which is applied to the high - temperature - resistant water - based coating described above. This usage method may include the following steps:

[0036] S21. Use an 80 - mesh to 240 - mesh sieve to filter out larger particles in the high - temperature - resistant water - based coating to prevent blockage of the subsequent spray gun.

[0037] S22. Adjust the condition viscosity of the filtered high - temperature - resistant water - based coating to 10 s - 12 s by adding water using a viscosity flow cup. The temperature in this step is preferably 23°C, and a No. 4 Ford cup is used.

[0038] S23. Add the filtered and viscosity - adjusted high - temperature - resistant water - based coating into a spray gun, and conduct spray - coding identification on a centrifugal casting pipe in a high - temperature production environment (600°C - 1400°C).

[0039] The coating is attached to the surface of the cast pipe for marking. The marking number can be a combination of 26 upper and lower case English letters from A to Z and 10 Arabic numerals from 0 to 9. After marking, the cast pipe fittings can be annealed in a high-temperature furnace at 1000 °C for 1 h, cooled by spraying water after annealing, and the temperature of the cast pipe is measured with a temperature gun until it drops to room temperature. System identification is carried out through a barcode scanner and data is uploaded. The high-temperature resistant water-based coating of the present invention can perform inkjet marking on centrifugally cast pipes in a high-temperature environment. The coating is stable in the high-temperature casting environment and subsequent heat treatment environment, and there is no peeling phenomenon even when strongly flushed with water (spraying water for cooling).

[0040] It should be noted that the above steps S21 and S22 can be directly carried out during the preparation process of the high-temperature resistant water-based coating (after step S15), or can be carried out before use (before step S23). The embodiments of the present invention do not make specific limitations on this.

[0041] Example 1

[0042] A high-temperature resistant water-based coating, by mass percentage, includes: 9.7 g of corundum powder, 15.15 g of titanium dioxide, 15.15 g of graphene quantum dots, 12 g of modified silicone resin, 0.38 g of polycarboxylate dispersant, 1.96 g of lithium-based bentonite, 0.05 g of sodium benzoate, 2.43 g of silicone defoamer, 0.05 g of bisamino silane complex, 0.44 g of propylene glycol and 42.69 g of water.

[0043] The preparation method of the high-temperature resistant water-based coating in this example may include the following steps:

[0044] S11. Mix the silicone resin and carboxyl-terminated nitrile rubber in a mass ratio of 9:1, and carry out a grafting reaction at 160 °C for 4 hours under nitrogen protection to obtain a high-temperature resistant modified silicone resin with a flexible chain segment.

[0045] S12. Turn on the multi-functional coating high-speed disperser, adjust the rotation speed to 2000 rpm, add 12 g of modified silicone resin and 42.69 g of water, and disperse for 15 min.

[0046] S13. Keep the rotation speed of the multi-functional coating high-speed disperser at 2000 rpm, add 0.38 g of polycarboxylate dispersant, and continue to disperse for 10 min.

[0047] S14. Increase the rotation speed of the multi-functional coating high-speed disperser to 2500 rpm, add 9.7 g of corundum powder, 15.15 g of titanium dioxide and 15.15 g of graphene quantum dots, and continue to disperse for 30 min.

[0048] S15. Keep the speed of the multi-functional coating high-speed disperser at 2500 rpm, add 1.96 g of lithium-based bentonite, 0.05 g of sodium benzoate, 2.43 g of silicone defoamer, 0.05 g of bis-aminosilane complex and 0.44 g of propylene glycol, and continue to disperse for 15 min to obtain the initial product of the high-temperature resistant water-based coating.

[0049] S21. Filter the initial product of the high-temperature resistant water-based coating obtained in step S15 through a 200-mesh sieve to remove larger particulate matters.

[0050] S22. Add water using a viscosity flow cup to adjust the conditional viscosity of the filtered product to 11.2 s to obtain the final product of the high-temperature resistant water-based coating.

[0051] For the final product of this example, after measurement, the pH value is 9.2, and the high-temperature adhesion, high-temperature heat preservation and sudden cold resistance performance are all excellent. The inkjet coating characters are clear and there is no gun clogging phenomenon. The high-temperature adhesion is tested using tinplate at 800 °C and reaches Class I index; the high-temperature heat preservation performance is tested by heat preservation at 1400 °C for 1 h and reaches Class I index; when cooled suddenly with cold water at high temperature, the sudden cold resistance performance reaches Class I index.

[0052] Example Two

[0053] A high-temperature resistant water-based coating, by mass percentage, includes: 5.85 g of silica powder, 17 g of titanium dioxide, 17 g of zinc oxide, 9.7 g of modified silicone resin, 0.38 g of polycarboxylate dispersant, 1.96 g of lithium-based bentonite, 0.12 g of sodium benzoate, 2.43 g of silicone defoamer, 0.12 g of bis-aminosilane complex, 0.44 g of propylene glycol and 45 g of water.

[0054] The preparation method of the high-temperature resistant water-based coating in this example may include the following steps:

[0055] S11. Mix the silicone resin and carboxyl-terminated nitrile rubber in a mass ratio of 9:1, and carry out a grafting reaction at 180 °C for 4 hours under nitrogen protection to obtain a high-temperature resistant modified silicone resin with a flexible chain segment.

[0056] S12. Turn on the multi-functional coating high-speed disperser, adjust the speed to 2000 rpm, add 9.7 g of modified silicone resin and 45 g of water, and disperse for 18 min.

[0057] S13. Keep the speed of the multi-functional coating high-speed disperser at 2000 rpm, add 0.38 g of polycarboxylate dispersant, and continue to disperse for 10 min.

[0058] S14. Increase the speed of the multi-functional coating high-speed disperser to 2500 rpm, add 5.85 g of silica powder, 17 g of titanium dioxide and 17 g of zinc oxide, and continue to disperse for 36 min.

[0059] S15, the multifunctional coating high-speed disperser maintains a rotation speed of 2500rpm, adds 1.96g lithium-based bentonite, 0.12g sodium benzoate, 2.43g silicone defoamer, 0.12g bisaminosilane complex and 0.44g propylene glycol, and continues to disperse for 15min to obtain the initial product of high temperature resistant water-based coating.

[0060] S21. Filter the initial product of the high temperature resistant water-based coating obtained in step S15 using a 100-mesh sieve to remove larger particles.

[0061] S22. Use a viscosity flow cup to add water to adjust the conditional viscosity of the filtered product to 10.8s to obtain the final product of high temperature resistant water-based coating.

[0062] The final product of this embodiment has a pH value of 9.6, and its high-temperature adhesion, high-temperature heat preservation and sudden cooling resistance are excellent. The inkjet coating has clear characters and no gun blocking. The high-temperature adhesion is tested at 800°C using tinplate, reaching the I-level index; the high-temperature heat preservation performance is tested at 1400°C for 1h, reaching the I-level index; the sudden cooling resistance is tested at high temperature using cold water, reaching the I-level index.

[0063] Embodiment 3

[0064] A high temperature resistant water-based paint comprises, by mass percentage, 7.28g of barium sulfate, 7.28g of aluminum hydroxide, 8.5g of titanium dioxide, 8.5g of zinc oxide, 8.5g of graphene quantum dots, 10.85g of modified silicone resin, 0.2g of acrylic dispersant, 3.2g of sodium bentonite, 0.1g of sodium benzoate, 2.6g of silicone defoamer, 0.32g of bisaminosilane complex, 0.86g of propylene glycol and 41.81g of water.

[0065] The method for preparing the high temperature resistant water-based coating may include the following steps:

[0066] S11. Mix the silicone resin and the carboxyl-terminated nitrile rubber in a mass ratio of 10:1, and carry out a grafting reaction at 160° C. for 4.5 hours under nitrogen protection to obtain a high-temperature resistant modified silicone resin modified with a flexible segment.

[0067] S12, turn on the multifunctional coating high-speed disperser, adjust the speed to 2000 rpm, add 10.85 g of modified silicone resin and 41.81 g of water, and disperse for 15 minutes.

[0068] S13, Multifunctional coating high-speed disperser maintains speed at 2000rpm, adds 0.2g acrylic dispersant, and continues to disperse for 15min.

[0069] S14, the multifunctional coating high-speed disperser increased the speed to 2700 rpm, added 7.28 g of barium sulfate, 7.28 g of aluminum hydroxide, 8.5 g of titanium dioxide, 8.5 g of zinc oxide and 8.5 g of graphene quantum dots, and continued to disperse for 35 minutes.

[0070] S15, the multifunctional coating high-speed disperser maintains a rotation speed of 2700 rpm, adds 3.2 g of sodium bentonite, 0.1 g of sodium benzoate, 2.6 g of silicone defoamer, 0.32 g of bisaminosilane complex and 0.86 g of propylene glycol, and continues to disperse for 15 minutes to obtain the initial product of high temperature resistant water-based coating.

[0071] S21. Filter the initial product of the high temperature resistant water-based coating obtained in step S15 through a 200-mesh sieve to remove larger particles.

[0072] S22. Use a viscosity flow cup to add water to adjust the conditional viscosity of the filtered product to 11.1s to obtain the final product of high temperature resistant water-based coating.

[0073] The final product of this embodiment has a pH value of 9.4, and its high-temperature adhesion, high-temperature heat preservation and sudden cooling resistance are excellent. The inkjet coating has clear characters and no gun blocking. The high-temperature adhesion is tested at 800°C using tinplate, reaching the I-level index; the high-temperature heat preservation performance is tested at 1400°C for 1h, reaching the I-level index; the sudden cooling resistance is tested at high temperature using cold water, reaching the I-level index.

[0074] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A high-temperature resistant water-based coating, characterized in that, By mass percentage, it includes: 5% - 15% filler A, 25% - 40% filler B, 5% - 12% binder, 0.1% - 0.5% dispersant, 1% - 5% suspending agent and 40% - 45% dispersion medium; The filler A is a high-temperature resistant filler; The filler B is a pigment and filler; The dispersion medium is water.

2. The high-temperature resistant water-based coating according to claim 1, wherein The high-temperature resistant filler includes at least one of corundum powder, alumina, silica powder, and silicon carbide.

3. The high-temperature resistant water-based coating according to claim 1, wherein, The pigment and filler includes at least one of titanium dioxide, zinc oxide, zinc phosphate, barium sulfate, nano-alumina, aluminum hydroxide, and graphene quantum dots.

4. The high-temperature resistant water-based coating according to claim 1, characterized in that It also includes 2% - 10% additives; The additives include at least one of preservatives, defoamers, adhesion promoters, and cosolvents.

5. The high-temperature resistant water-based coating according to claim 1, characterized in that The binder is a modified silicone resin.

6. The high-temperature resistant water-based coating according to claim 5, wherein The modified silicone resin is a high-temperature resistant silicone resin modified with a flexible chain segment using carboxyl-terminated nitrile rubber.

7. The high-temperature resistant water-based coating according to claim 1, characterized in that, The dispersant includes at least one of polycarboxylate dispersants, polyurethane dispersants, and acrylic dispersants.

8. The high-temperature resistant water-based coating according to claim 1, wherein The suspending agent includes at least one of sodium-based bentonite, lithium-based bentonite, attapulgite, sodium carboxymethyl cellulose, sodium alginate, and xanthan gum.

9. A preparation method, applied to the high-temperature resistant water-based coating according to any one of claims 1 to 8, characterized in that, It includes the following steps: S1. High-speed shear and disperse the binder and the dispersion medium for 10 min - 20 min; S2. Add the dispersant and high-speed shear and disperse for 5 min - 15 min; S3. Add the filler A and the filler B and high-speed shear and disperse for 20 min - 40 min; S4. Add the suspending agent and high-speed shear and disperse for 10 min - 20 min to obtain the high-temperature resistant water-based coating.

10. A method of use, applied to the high-temperature resistant water-based coating according to any one of claims 1 to 8, characterized in that, The high-temperature resistant water-based coating is used for inkjet marking of centrifugal cast pipes in a high-temperature production environment.