A method for preparing a radiation-insulating and corrosion-resistant functional coating

Abstract

This invention discloses a method for preparing a radiation-insulating and corrosion-resistant functional coating. The method includes: (1) dispersing ATO nanoparticles in deionized water and adding a strong oxidizing agent under stirring to react; (2) dispersing the ATO nanoparticles obtained in step (1) in an acid solution and then adding lignocellulose under stirring to react; (3) washing and drying the obtained ATO nanoparticles-lignocellulose to obtain modified nano-ATO functional particles; (4) adding the modified nano-ATO functional particles, organic epoxy resin, curing agent and optional additives to a reactor in proportion and mixing thoroughly. This invention utilizes lignocellulose to modify ATO, improving the dispersibility of ATO functional particles, and the resulting functional coating has significantly improved heat insulation performance and physical properties.

Description

Technical Field

[0001] This invention belongs to the field of chemical raw materials and chemical products manufacturing, and specifically relates to a method for preparing a radiation-insulating and anti-corrosion functional coating. Background Technology

[0002] To prevent the energy from sunlight from accumulating on the surface of an object and causing it to heat up, a coating is needed to dissipate the heat. Radiation coatings work by dissipating heat through radiation, radiating the accumulated heat from the object's surface into the external space, thus reducing the object's residual temperature. Even on cloudy days and at night, when there is no energy input, the coating can still lower the surface temperature through radiant heat. However, the fillers used in these functional coatings have poor dispersibility in the resin, the preparation process is relatively complex, and the cost is relatively high. Further research is needed on the preparation methods for this type of coating.

[0003] ATO, as a radiation-functional filler, is commonly used in the preparation of radiation-type heat-insulating coatings. However, ATO exhibits poor dispersibility in slurries. To improve the dispersibility of ATO in coatings, silane coupling agents such as KH-550 and KH-570 are often used. Under certain conditions, ATO reacts with the coupling agent, grafting organic side chains onto the ATO surface, thereby improving its compatibility with the organic resin matrix. However, this method is relatively simple and does not improve the weather resistance or flexibility of the coating. ATO can also be modified with lignocellulose, typically by sulfonating the lignocellulose before reacting it with ATO. However, this increases the difficulty of the reaction, making the process more complex and limiting its large-scale application.

[0004] Antimony tin oxide (ATO) is a metal-doped oxide that is often used to prepare radiation-insulating coatings because it has a certain radiative effect in the infrared region of sunlight. However, as an inorganic metal oxide, it has poor compatibility with organic polymer resin matrices. Furthermore, ATO particles have high surface energy and a certain amount of hydroxyl groups distributed on their surface. These hydroxyl groups easily form hydrogen bonds between particles, causing them to aggregate. At the same time, substances tend to be relatively stable, and the high surface energy ATO particles will also concentrate in large quantities to reduce their surface energy and maintain stability.

[0005] In coatings, this manifests as a large agglomeration of ATO particles, resulting in extremely uneven dispersion and consequently, inconsistent radiative thermal insulation properties. Areas with a higher concentration of functional particles exhibit stronger infrared radiation and better insulation; however, due to severe particle agglomeration, the resin cannot completely encapsulate the nanoparticles, affecting the surface smoothness of the coating and leading to defects such as pinholes and craters. This negatively impacts the coating's basic physical properties and corrosion resistance. In areas with fewer ATO particles, the coating is merely a transparent resin layer, offering no infrared radiation blocking effect. Light can directly penetrate the coating and reach the interior of the object, rendering the coating ineffective in providing thermal insulation and cooling. Therefore, improving the dispersion of ATO functional particles in the coating is crucial for enhancing its overall performance. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a radiation-insulating and corrosion-resistant functional coating, so as to solve the technical problem of poor dispersibility of the coating system obtained by existing dispersion technology and coating preparation methods.

[0007] The present invention discloses a method for preparing a radiation-insulating and corrosion-resistant functional coating, comprising the following:

[0008] (1) Disperse ATO nanoparticles in deionized water, add a strong oxidizing agent while stirring, adjust the pH value to 1-2, and oxidize for a period of time; wash and dry the resulting ATO nanoparticles.

[0009] (2) The ATO nanoparticles obtained in step (1) are dispersed in an acid solution, and then lignocellulose is added under stirring to carry out the reaction;

[0010] (3) The ATO nanoparticles-lignocellulose obtained in step (2) are washed and dried to obtain modified nano-ATO functional particles;

[0011] (4) The modified nano-ATO functional particles, organic epoxy resin, curing agent and optional additives obtained in step (3) are added to the reactor in proportion and mixed thoroughly to obtain a radiation heat insulation functional coating.

[0012] Furthermore, in the above technical solution, the strong oxidizing agent mentioned in step (1) includes one or more of potassium permanganate, concentrated sulfuric acid, potassium dichromate, concentrated nitric acid, and carbon tetrachloride, preferably potassium permanganate and potassium dichromate. In step (1), the pH value of the system can be adjusted by controlling the amount of concentrated acid reagents such as concentrated sulfuric acid and concentrated nitric acid.

[0013] Furthermore, in the above technical solution, the washing and drying of ATO particles in step (1) adopts conventional operations in the field. For example, washing can be done by centrifugal washing, and the drying conditions are generally: drying temperature is 25±10 ℃, and drying time is generally 12±6 h.

[0014] Furthermore, in the above technical solution, the acid solution mentioned in step (2) is selected from at least one of dilute hydrochloric acid and dilute sulfuric acid solution. The dispersion can be carried out by mechanical stirring or ultrasonic dispersion, preferably ultrasonic dispersion. The reaction temperature is 80±15 ℃, and the reaction time is generally 2-6 h.

[0015] Furthermore, in the above technical solution, the washing needs to continue until the solution pH value is 7-8; the drying adopts conventional operations in the art.

[0016] Furthermore, the optional additives are selected from at least one of dispersants, defoamers, leveling agents, thickeners, etc.

[0017] Furthermore, in the above technical solution, the mixing method of the coating in step (4) adopts conventional operation in the art. The mixing temperature is generally 25±10 ℃, and the stirring speed is generally 600±100 rpm.

[0018] Furthermore, a heat-insulating and corrosion-resistant functional coating was prepared using the modified nanoparticles from step (3) as fillers. The coating matrix was an organic epoxy resin, the curing agent was an aliphatic amine, and other additives included dispersants, defoamers, leveling agents, thickeners, etc. The auxiliary functional fillers included rust inhibitors, descaling agents, etc. The coating method was spraying, and the curing conditions were generally a temperature of 25±10 ℃ and a humidity of 50±15%.

[0019] Based on research findings, the applicant discovered that both ATO functional particles and lignocellulose have active groups on their surfaces capable of condensation reactions. By utilizing these active reactive groups (mainly hydroxyl groups), under suitable reaction conditions, the hydroxyl groups on the ATO surface can be oxidized to carboxyl groups, which then undergo a condensation reaction with the hydroxyl groups on the lignocellulose surface. This condensation reaction generates ester bonds, forming a unified whole between ATO and lignocellulose. Simultaneously, due to the good compatibility of lignocellulose with the epoxy resin matrix, the modified ATO particles bond together with the lignocellulose, thus improving the dispersibility of ATO in the resin matrix. When the ATO particles are more uniformly dispersed, the thermal insulation performance of the coating is more uniform throughout, and the stress concentration points caused by the aggregation of ATO particles are reduced, resulting in a significant improvement in the thermal insulation and physical properties of the coating. Because the hydroxyl groups on the surfaces of lignocellulose and ATO are not highly reactive, the reaction rate is slow and the conversion rate is low at room temperature. Therefore, ATO particles can be subjected to strong acid oxidation treatment. Under strong acid conditions, the hydroxyl groups are oxidized to carboxyl groups, increasing the number of carboxyl groups on the particle surface. As the number of reactive groups increases, the esterification reactivity improves, and a higher reaction temperature is provided, thereby increasing the reaction rate and promoting the esterification reaction.

[0020] Compared with the prior art, the method of the present invention has the following beneficial effects:

[0021] 1. The modified ATO functional coating prepared by this invention has radiation heat insulation function. The addition of lignocellulose gives the coating a certain weather resistance and also helps to improve the toughness of the coating.

[0022] 2. Lignocellulose, as a natural bio-based polymer, is green, environmentally friendly, and pollution-free, making it more friendly to humans and the environment. It can degrade naturally. Its sources are widespread and abundant in nature, which can significantly reduce operating costs.

[0023] 3. Compared with the traditional method of improving the dispersibility of ATO particles using silane coupling agents, this invention provides a new approach to modifying the surface of ATO, which improves particle dispersibility, simplifies the reaction process, reduces production costs, and avoids the adverse effects of sulfonation on the material's own properties.

[0024] In summary, the method of this invention for modifying ATO nanoparticles and preparing a radiation-insulating thermal coating has certain advantages. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the self-made temperature difference testing device used in this invention.

[0026] Among them, 1-infrared lamp, 2-blank sample, 3-test plate, 4-thermocouple, 5-thermometer, 6-foam box. Detailed Implementation

[0027] The present invention will now be described in more detail with reference to specific embodiments.

[0028] Thermal insulation temperature difference test: Thermal insulation temperature difference is the most intuitive way to characterize the thermal insulation performance of a coating; however, there is currently no unified standard for testing thermal insulation temperature difference. This article refers to the thermal insulation temperature difference test method in HG / T 4341-2012 "Heat Reflective Coatings for Metal Surfaces" and uses a self-made experimental device for testing.

[0029] This apparatus uses a polystyrene foam insulation box measuring 420 mm × 330 mm × 330 mm with a wall thickness of 50 mm. The interior is divided into two sections by a 50 mm thick foam material. A 150 mm × 70 mm notch is cut at the top of each compartment. The test panel and a blank sample are placed on these notches, respectively. Two 250 W infrared lamps are placed directly above each compartment to uniformly irradiate the samples. Thermocouples are used to measure the temperature of the back of the test panel and the temperature inside the insulation box. The temperature difference between the back of the blank sample and the stable temperature of the test panel after a period of irradiation is used to represent the thermal insulation temperature difference of the sample. The sample substrate is a 150 mm × 70 mm × 2 mm sandblasted steel plate, coated with a primer + intermediate coat + topcoat system. After coating, the sample needs to be cured in a constant temperature and humidity chamber for 7 days. The test is conducted at 25 ± 10 ℃.

[0030] Example 1

[0031] 5 g of ATO nanoparticles were dispersed in 20 mL of deionized water. While stirring, 0.83 g of potassium permanganate was added to adjust the pH to 1.5, and the oxidation reaction was carried out for 8 h. The oxidized ATO nanoparticles were then washed three times with alcohol and three times with water, and dried in an oven at 35 °C for 18 h. The dried ATO particles were then added to 20 mL of dilute sulfuric acid and sonicated for 30 min to disperse the oxidized ATO particles. Then, 7.6 g of dispersed lignocellulose was added while heating and stirring at 95 °C. The mixture was then maintained at 95 °C and sonicated for 6 h to ensure complete reaction. The condensation-modified ATO nanoparticles-lignocellulose were centrifuged and washed several times until the solution pH reached 7. The solution was then dried in an oven at 35 °C for 24 h to obtain modified ATO functional particles.

[0032] Add 5 g of modified particles to deionized water, stir and disperse, then add 0.5 g of dispersant, 0.1 g of defoamer, and 2.6 g of leveling agent in sequence. After dispersing evenly, add 25 g of organic epoxy resin, stir evenly, add auxiliary functional filler, and finally add 3.57 g of fatty amine curing agent. Mix thoroughly to obtain radiation heat insulation functional coating.

[0033] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 25 ℃ and 50% humidity for 7 days. Its performance was then tested.

[0034] Example 2

[0035] 8.5 g of ATO nanoparticles were dispersed in 30 mL of deionized water. While stirring, 2.1 g of potassium dichromate was added to adjust the pH to 1, and the oxidation reaction was carried out for 2 h. The oxidized ATO nanoparticles were then washed three times with alcohol and three times with water, and dried in an oven at 25 °C for 12 h. The dried ATO particles were then added to 35 mL of dilute hydrochloric acid and sonicated for 60 min to disperse the oxidized ATO particles. Then, 10.2 g of dispersed lignocellulose was added while heating and stirring at 65 °C. The mixture was then maintained at 65 °C and sonicated for 2 h to ensure complete reaction. The condensation-modified ATO nanoparticles-lignocellulose were centrifuged and washed several times until the solution pH reached 7.5. The solution was then dried in an oven at 25 °C for 24 h to obtain the modified ATO functional particles.

[0036] 15.5 g of modified particles were added to deionized water and stirred to disperse. Then, 1.25 g of dispersant, 0.3 g of defoamer, and 7.2 g of leveling agent were added sequentially. After uniform dispersion, 77.5 g of organic epoxy resin was added and stirred until homogeneous. Auxiliary functional fillers were then added, and finally, 11.2 g of fatty amine curing agent was added. After curing for approximately 10 minutes, the mixture was sprayed onto a spray gun and then placed in a constant temperature and humidity chamber at 25 ℃ and 50% humidity for 7 days. Its performance was then tested.

[0037] Example 3

[0038] 5 g of ATO nanoparticles were dispersed in 20 mL of deionized water. While stirring, 1.46 g of concentrated nitric acid was added to adjust the pH to 1.5, and the oxidation reaction was carried out for 4 h. The oxidized ATO nanoparticles were then washed three times with alcohol and three times with water, and dried in an oven at 25 °C for 13 h. The dried ATO particles were then added to 20 mL of dilute sulfuric acid, and mechanically stirred for 30 min to disperse the oxidized ATO particles. Then, 8.5 g of dispersed lignocellulose was added while heating and stirring at 75 °C. The mixture was then maintained at 75 °C and ultrasonically dispersed for 3 h to ensure complete reaction. The condensation-modified ATO nanoparticles-lignocellulose were centrifuged and washed several times until the solution pH reached 7, and then dried in an oven at 25 °C for 24 h to obtain modified ATO functional particles.

[0039] Take 6 g of modified particles and add them to deionized water. After stirring and dispersing, add 0.5 g of dispersant, 0.1 g of defoamer, and 2.6 g of leveling agent in sequence. After dispersing evenly, add 25 g of organic epoxy resin, stir evenly, add auxiliary functional filler, and finally add 3.57 g of fatty amine curing agent. Mix thoroughly to obtain radiation heat insulation functional coating.

[0040] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 25 ℃ and 50% humidity for 7 days. Its performance was then tested.

[0041] Example 4

[0042] Eight g of ATO nanoparticles were dispersed in 20 mL of deionized water. While stirring, 3.25 g of carbon tetrachloride was added to adjust the pH to 2.5, and the oxidation reaction was carried out for 3.5 h. The oxidized ATO nanoparticles were then washed three times with alcohol and three times with water, and dried in an oven at 30 °C for 15 h. The dried ATO particles were then added to 40 mL of dilute hydrochloric acid and sonicated for 30 min to disperse the oxidized ATO particles. Then, 9.5 g of dispersed lignocellulose was added while heating and stirring at 95 °C. The mixture was then maintained at 95 °C and sonicated for 5 h to ensure complete reaction. The condensation-modified ATO nanoparticles-lignocellulose were centrifuged and washed several times until the solution pH reached 7. The solution was then dried in an oven at 25 °C for 24 h to obtain modified ATO functional particles.

[0043] Add 5 g of modified particles to deionized water, stir and disperse, then add 0.5 g of dispersant, 0.1 g of defoamer, and 2.6 g of leveling agent in sequence. After dispersing evenly, add 25 g of organic epoxy resin, stir evenly, add auxiliary functional filler, and finally add 3.57 g of fatty amine curing agent. Mix thoroughly to obtain radiation heat insulation functional coating.

[0044] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 30 ℃ and 50% for 7 days. Its performance was then tested.

[0045] Example 5

[0046] 5 g of ATO nanoparticles were dispersed in 20 mL of deionized water. While stirring, 1.35 g of potassium permanganate was added to adjust the pH to 1.5, and the oxidation reaction was carried out for 3.5 h. The oxidized ATO nanoparticles were then washed three times with alcohol and three times with water, and dried in an oven at 30 °C for 8 h. The dried ATO particles were then added to 20 mL of dilute sulfuric acid and sonicated for 30 min to disperse the oxidized ATO particles. Then, while heating and stirring at 70 °C, 7.6 g of dispersed lignocellulose was added, and the reaction was maintained at 70 °C while sonicating to ensure complete dispersion. The condensation-modified nano-ATO-lignocellulose was centrifuged and washed several times until the solution pH reached 8, and then dried in an oven at 25 °C for 24 h to obtain modified ATO functional particles.

[0047] Take 10 g of modified particles and add them to deionized water. After stirring and dispersing, add 1.5 g of dispersant, 0.4 g of defoamer, and 5.2 g of leveling agent in sequence. After dispersing evenly, add 65 g of organic epoxy resin, stir evenly, add auxiliary functional filler, and finally add 15 g of fatty amine curing agent. Mix thoroughly to obtain radiation heat insulation functional coating.

[0048] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 25 ℃ and 65% for 7 days. Its performance was then tested.

[0049] Example 6

[0050] 5 g of ATO nanoparticles were dispersed in 20 mL of deionized water. While stirring, 1.75 g of potassium permanganate was added to adjust the pH to 1.5, and the oxidation reaction was carried out for 3.5 h. The oxidized ATO nanoparticles were then washed three times with alcohol and three times with water, and dried in an oven at 25 °C for 10 h. The dried ATO particles were then added to 20 mL of dilute sulfuric acid and sonicated for 30 min to disperse the oxidized ATO particles. Then, while heating and stirring at 90 °C, 12.5 g of dispersed lignocellulose was added, and the mixture was sonicated for 4 h to ensure complete reaction. The condensation-modified ATO nanoparticles-lignocellulose were centrifuged and washed several times until the solution pH reached 7.5, and then dried in an oven at 25 °C for 48 h to obtain modified ATO functional particles.

[0051] Take 12 g of modified particles and add them to deionized water. After stirring and dispersing, add 0.8 g of dispersant, 0.5 g of defoamer, and 4.5 g of leveling agent in sequence. After dispersing evenly, add 25 g of organic epoxy resin, stir evenly, add auxiliary functional filler, and finally add 3.57 g of fatty amine curing agent. Mix thoroughly to obtain radiation heat insulation functional coating.

[0052] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 20 ℃ and 60% humidity for 7 days. Its performance was then tested.

[0053] Comparative Example 1

[0054] Take 12 g of ATO nanoparticles and add them to deionized water. After stirring and dispersing, add 0.8 g of dispersant, 0.5 g of defoamer, 4.5 g of leveling agent, and 0.4 g of calcium lignosulfonate in sequence. After dispersing evenly, add 25 g of organic epoxy resin, stir evenly, add auxiliary functional filler, and finally add 3.57 g of fatty amine curing agent. Mix thoroughly to obtain a radiation heat insulation functional coating.

[0055] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 25 ℃ and 50% humidity for 7 days. Its performance was then tested.

[0056] Comparative Example 2

[0057] 12 g of ATO nanoparticles were added to deionized water and stirred to disperse. Then, 0.8 g of dispersant, 0.5 g of defoamer, 4.5 g of leveling agent, and 4.3 g of coupling agent were added sequentially. After being dispersed evenly, 25 g of organic epoxy resin was added. The mixture was vacuumed and stirred at 80-120 °C for 2 h. After stirring evenly, auxiliary functional fillers were added, and finally 3.57 g of fatty amine curing agent was added. The mixture was thoroughly mixed to obtain a radiation heat insulation functional coating.

[0058] The resulting coating was sprayed after curing for approximately 10 minutes, and then placed in a constant temperature and humidity chamber at 25 ℃ and 50% humidity for 7 days. Its performance was then tested.

[0059] Table 1

[0060]

[0061] The anti-corrosion performance of all embodiments and comparative examples meets the national coating standards and production application requirements.

Claims

1. A method for preparing a radiation shielding anticorrosive functional coating, characterized by, The application comprises the following steps: (1) dispersing ATO nanoparticles in deionized water, adding a strong oxidizing agent under stirring, adjusting the pH value to 1-2, and oxidizing for a period of time; washing and drying the obtained ATO nanoparticles; (2) dispersing the obtained ATO nanoparticles in step (1) in an acid solution, then adding lignocellulose under stirring, and reacting; (3) washing and drying the obtained ATO nanoparticle-lignocellulose in step (2) to obtain modified nano ATO functional particles; (4) adding the modified nano ATO functional particles obtained in step (3), organic epoxy resin, curing agent and optional additives into a reactor according to a certain proportion, mixing them thoroughly and uniformly to prepare a radiation heat insulation functional coating.

2. The production method according to claim 1, characterized by, The strong oxidizing agent comprises one or more of potassium permanganate, concentrated sulfuric acid, potassium dichromate and concentrated nitric acid.

3. The production method according to claim 1, characterized by, The reaction time in step (1) is 2-8 h.

4. The production method according to claim 1, characterized by, The drying conditions in step (1) are as follows: the drying temperature is 25±10 ℃, and the drying time is 12±6 h.

5. The preparation method according to claim 1, characterized in that, The acid solution in step (2) is at least one selected from dilute hydrochloric acid and dilute sulfuric acid solution.

6. The method of claim 1, wherein, The dispersion is carried out by mechanical stirring or ultrasonic dispersion.

7. The production method according to claim 1, characterized by, The reaction temperature in step (2) is 80±15 ℃, and the reaction time is 2-6 h.

8. The method of claim 1, wherein, The optional additives are at least one selected from dispersants, defoamers, leveling agents and thickening agents.

9. The production method according to claim 1, characterized by, The mixing temperature in step (4) is 25±10 ℃.

10. The method of claim 1, wherein, The curing agent is a fatty amine.

11. The preparation method according to claim 2, characterized in that, The strong oxidizing agent is selected from potassium permanganate and / or potassium dichromate.

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