A light-shielding paint having high weather resistance and coating adhesion and a preparation method thereof

Abstract

The present application relates to a kind of high weather resistance and coating adhesion sunscreen coating and its preparation method, belong to sunscreen coating technical field;The present application uses the modifier with disulfide bond and polymerizable double bond to modify polyacrylate emulsion, significantly improve the flexibility of polyacrylate molecular chain after modification, reduce solidification shrinkage stress and internal stress, improve the coating adhesion of sunscreen coating of hard filler to matrix resin, it can also form stable chemical bonding between polyacrylate resin and titanium dioxide, provide stable stress transfer path, reduce the cracking and warping of coating, in addition, the modifier of the present application has good heat resistance aromatic ring structure, using the modifier of the present application can improve the heat resistance of sunscreen coating without introducing additional modifier.

Description

Technical Field

[0001] This invention belongs to the field of light-blocking coating technology, specifically, it relates to a light-blocking coating with high weather resistance and coating adhesion, and its preparation method. Background Technology

[0002] Light-blocking coatings are an important branch of functional coating materials. They can effectively reflect, scatter, or absorb incident light, preventing it from penetrating the coating and reaching the substrate. To achieve good light-blocking performance, a large amount of light-blocking pigments need to be added to the base resin. Excessive light-blocking pigment particles will severely crowd out the space of the film-forming resin, which serves as the "skeleton" and adhesive of the coating. This results in insufficient resin to completely wet and coat all pigment particles, and the inability to form a continuous and dense resin phase film between the particles. The continuity of the resin phase is disrupted, becoming fragmented. Therefore, the adhesion of light-blocking coatings is generally poor. To solve the above technical defects, this invention provides a light-blocking coating with high weather resistance and coating adhesion, as well as its preparation method. Summary of the Invention

[0003] The purpose of this invention is to provide a light-shielding coating with high weather resistance and coating adhesion, and a method for preparing the same, to solve the problems mentioned in the background art.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A method for preparing a light-blocking coating with high weather resistance and coating adhesion includes the following steps:

[0006] S1. A pyridine derivative with a carboxyl group, 2,2'-dithiodiethanol, p-toluenesulfonic acid, and N,N-dimethylformamide were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 110-130°C, and then the reaction was carried out at 110-130°C for 3-4 hours. After the reaction was completed, the reaction solution was poured into deionized water and extracted with ethyl acetate. The organic phase was then separated, and the organic phase was eluted by silica gel column chromatography after rotary evaporation to obtain the intermediate.

[0007] S2. Mix the intermediate, haloalkanes, and acetonitrile in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, raise the temperature of the system to 55-75°C. Then react at 55-75°C for 6-12 hours. After the reaction is complete, remove the solvent by rotary evaporation to obtain the modifier.

[0008] S3. Mix titanium dioxide, silane coupling agent, and ethanol solution in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, raise the system temperature to 50-80℃. Then react at 50-80℃ for 4-8 hours. After the reaction is complete, filter out the solid and wash it with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide.

[0009] S4. Methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, and the first batch of deionized water are mixed in a reactor and dispersed by high-speed stirring to obtain a pre-emulsion. The pre-emulsion is then divided into two batches, and the first batch of pre-emulsion, the first batch of initiator, and the second batch of deionized water are added to a new reactor. The reaction is carried out at a temperature of 76-82℃ for 20-30 minutes to obtain a seed emulsion. Then, a modifier is added to the reactor, and aqueous solutions of the second batch of pre-emulsion and the second batch of initiator are added dropwise. After the addition is completed, the temperature is raised to 84-88℃ and kept at this temperature for 50-70 minutes to complete the polymerization. After cooling, the pH of the system is adjusted to 6.5-7.5, and the mixture is filtered to obtain a modified polyacrylate emulsion.

[0010] S5. Add deionized water, dispersant, wetting agent, and thickener to a high-speed disperser and stir until evenly mixed. Then add modified titanium dioxide and filler. After high-speed dispersion, reduce the speed and add modified polyacrylate emulsion, film-forming aid, defoamer, and UV absorber. After the addition is complete, keep the speed constant and continue stirring for a period of time. Then adjust the pH of the system to 8-9, let it stand and mature, and then filter to remove large solid particles to obtain a light-blocking coating with high weather resistance and coating adhesion.

[0011] Furthermore, the pyridine derivative with a carboxyl group is at least one of nicotinic acid and isonicotinic acid.

[0012] Furthermore, the halohydrocarbon is at least one of 3-chloropropene and 4-chloro-1-butene.

[0013] Furthermore, the silane coupling agent is at least one of KH-580 and KH-590.

[0014] Furthermore, the emulsifier is at least one of AEO-9, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0015] Furthermore, the initiator is at least one of potassium persulfate and ammonium persulfate, and the mass fraction of the initiator aqueous solution is preferably 5%.

[0016] Furthermore, the dispersant is a polyacrylate dispersant, preferably one of OROTAN 731A and Hydropalat® 5050.

[0017] Furthermore, the wetting agent is an acrylate wetting agent, preferably one of ZH-5011 and QHL608.

[0018] Furthermore, the thickener is hydroxyethyl cellulose.

[0019] Furthermore, the filler is at least one of calcined kaolin and wollastonite powder.

[0020] Furthermore, the film-forming aid is at least one of Texanol and alcohol ester-12.

[0021] Furthermore, the defoamer is an organosilicon defoamer, preferably one of SAG 622 and BYK-1786.

[0022] Furthermore, the ultraviolet absorber is at least one of UV-1130 and Tinuvin 400.

[0023] Preferably, the pH adjuster used to adjust the pH is AMP-95.

[0024] Furthermore, the mass fractions of pyridine derivative, 2,2'-dithiodiethanol, p-toluenesulfonic acid, and N,N-dimethylformamide in S1 are 11.6–15.4: 6.4–8.6: 0.5–0.7: 54–72.

[0025] Furthermore, the mass ratio of intermediate, haloalkanes, and acetonitrile in S2 is 12.4–17.4: 7.6–12.6: 40–60.

[0026] Furthermore, the ethanol solution used in S3 is an aqueous ethanol solution with a volume fraction of 40-60%, and the mass ratio of titanium dioxide, silane coupling agent, and ethanol solution is 25-35:7.5-10.5:800-1000.

[0027] Furthermore, the mass ratio of the aqueous solutions of methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, first batch of deionized water, first batch of preemulsion, first batch of initiator, second batch of deionized water, modifier, second batch of preemulsion, and second batch of initiator in S4 is 10–16:15–25:1.5–2.5:0.4–1.2:28–46:10–17:0.05–0.1:10–17:8–12:40–68:2–4.

[0028] Furthermore, the mass ratio of deionized water, dispersant, wetting agent, thickener, modified titanium dioxide, filler, modified polyacrylate emulsion, film-forming aid, defoamer, and ultraviolet absorber in S5 is 18–22: 0.6–1.2: 0.1–0.2: 0.2–0.6: 25–35: 5–10: 30–35: 1–2: 0.4–0.6: 0.2–0.4.

[0029] Furthermore, the high-speed stirring dispersion conditions for the preemulsion in S4 are 3000–4000 rpm and the time conditions are 6–10 min.

[0030] Furthermore, the time for adding the second batch of preemulsion in S4 is 2-3 hours, and the time for adding the aqueous solution of the second batch of initiator is 2.5-3.5 hours. Preferably, the second batch of initiator should be added within 10-30 minutes after the second batch of preemulsion is started.

[0031] Furthermore, the high-speed dispersion conditions in S5 are 1000–1400 rpm and 20–40 min, and the reduced speed conditions are 250–350 rpm. After adding all the raw materials, the stirring time is 15–25 min.

[0032] A light-blocking coating with high weather resistance and coating adhesion is prepared by any of the above preparation steps.

[0033] This invention has at least one of the following beneficial effects:

[0034] This invention uses pyridine derivatives with carboxyl groups and 2,2'-dithiodiethanol as raw materials. An intermediate is obtained by esterification of the carboxyl groups in the pyridine derivatives with the hydroxyl groups in the 2,2'-dithiodiethanol under the catalysis of p-toluenesulfonic acid. Then, using the intermediate and haloalkanes as raw materials, a modifier is obtained by reacting the pyridine structure in the intermediate with the halogen atoms in the haloalkanes to form a quaternary ammonium salt. The modifier of this invention contains disulfide bonds and polymerizable double bonds. During polymerization with acrylate monomers, the disulfide bonds can break and recombine under the action of an initiator, reacting with the broken sulfur free radicals or double bonds to reform disulfide bonds or initiate chain growth. This significantly improves the flexibility of the polyacrylate molecular chain, reduces curing shrinkage stress and internal stress, increases the coating degree of the matrix resin on the hard filler, and thus improves the adhesion of the light-shielding coating.

[0035] The modifier of the present invention can introduce heat-resistant aromatic ring structures into the main chain and branches of the polyacrylate emulsion molecular chain after polymerization. Using the modifier of the present invention can improve the heat resistance of the light-blocking coating without introducing additional modifiers.

[0036] The modified polyacrylate emulsion of this invention contains disulfide bonds, while the titanium dioxide surface modified with a silane coupling agent is grafted with thiol groups. After the light-shielding coating is prepared, the disulfide bonds in the polyacrylate emulsion can undergo a reversible thiol-disulfide bond exchange reaction with the thiol groups on the titanium dioxide surface, forming a stable chemical bond between the polyacrylate resin and the titanium dioxide. This significantly improves the interfacial stability of the light-shielding coating, thereby improving the coating adhesion and providing a stable stress transfer path, reducing coating cracking and warping. In addition, the tighter chemical bond connection can effectively reduce the penetration of moisture, acidic media, etc. into the interfacial channels, thereby improving the long-term weather resistance of the coating.

[0037] The light-shielding coating of the present invention contains a dynamic self-healing system of mercapto-disulfide bonds, and the molecular chain segments have good flexibility, which can spontaneously achieve slow self-repair of internal minor damage. Moreover, when the temperature rises, it can effectively accelerate the self-healing reaction. This self-healing ability can effectively improve the weather resistance of the coating, reduce the maintenance frequency, and extend the service life of the coating.

[0038] The light-shielding coating of the present invention contains a large number of quaternary ammonium salt structures. The quaternary ammonium salt structures are positively charged and can generate electrostatic attraction with uncharged or negatively charged substrates, which significantly improves the adhesion of the coating. In addition, the quaternary ammonium salt structures can also form channels for electrostatic dissipation inside the coating, providing a certain degree of antistatic properties, reducing the electrostatic adsorption of dust on the coating surface, and keeping the coating clean and beautiful. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments in this application specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection claimed in this application.

[0040] The raw materials used in this invention are not particularly restricted in terms of their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art. Example

[0041] A method for preparing a light-blocking coating with high weather resistance and coating adhesion includes the following steps:

[0042] S1. By mass, 11.6 parts of nicotinic acid, 6.4 parts of 2,2'-dithiodiethanol, 0.5 parts of p-toluenesulfonic acid, and 54 parts of N,N-dimethylformamide were mixed in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 110°C, and the reaction was carried out at 110°C for 4 hours. After the reaction was completed, the reaction solution was poured into deionized water and extracted with ethyl acetate. The organic phase was then separated, and the organic phase was obtained by rotary evaporation and elution by silica gel column chromatography.

[0043] S2. By mass, 12.4 parts of intermediate, 7.6 parts of 3-chloropropene, and 40 parts of acetonitrile were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 55°C. The reaction was then carried out at 55°C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation to obtain the modifier.

[0044] S3. By mass, 25 parts of titanium dioxide, 7.5 parts of silane coupling agent KH-590, and 800 parts of 60% ethanol aqueous solution were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 50°C, and then the reaction was carried out at 50°C for 8 hours. After the reaction was completed, the solid was filtered out and washed with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide.

[0045] S4. By mass, 10 parts methyl methacrylate, 15 parts butyl acrylate, 1.5 parts methacrylic acid, 0.4 parts AEO-9, and the first batch of 28 parts deionized water are mixed in a reactor. The mixture is stirred at 3000 rpm for 10 minutes to obtain a pre-emulsion. The pre-emulsion is then divided into two batches. The first batch of 10 parts pre-emulsion, the first batch of 0.05 parts potassium persulfate, and the second batch of 10 parts deionized water are added to a new reactor, and the mixture is reacted at 76°C. The seed emulsion was obtained by polymerization for 30 minutes. Then, 8 parts of modifier were added to the reactor, and 40 parts of pre-emulsion were added dropwise over 2 hours. 10 minutes after the second batch of pre-emulsion was added, 2 parts of 5% potassium persulfate aqueous solution were added dropwise over 2.5 hours. After the addition was completed, the temperature was raised to 84°C and the reaction was maintained at that temperature for 70 minutes to complete the polymerization. After cooling, AMP-95 was added to adjust the pH of the system to 6.5. The modified polyacrylate emulsion was obtained by filtration.

[0046] S5. By mass, add 18 parts deionized water, 0.6 parts OROTAN 731A, 0.1 parts ZH-5011, and 0.2 parts hydroxyethyl cellulose to a high-speed disperser and mix thoroughly. Then add 25 parts modified titanium dioxide and 5 parts calcined kaolin. Stir at 1000 rpm for 40 minutes, then reduce the speed to 250 rpm and add 35 parts modified polyacrylate emulsion, 1 part Texanol, 0.4 parts SAG 622, and 0.2 parts UV-1130. After the addition is complete, continue stirring at the same speed for 25 minutes. Then add AMP-95 to adjust the pH of the system to 8. After standing and maturing, filter to remove large solid particles to obtain a light-blocking coating with high weather resistance and coating adhesion.

[0047] A light-blocking coating with high weather resistance and coating adhesion is prepared by the above preparation steps. Example

[0048] A method for preparing a light-blocking coating with high weather resistance and coating adhesion includes the following steps:

[0049] S1. By mass, 15.4 parts of nicotinic acid, 8.6 parts of 2,2'-dithiodiethanol, 0.7 parts of p-toluenesulfonic acid, and 72 parts of N,N-dimethylformamide were mixed in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 130°C, and the reaction was carried out at 130°C for 3 hours. After the reaction was completed, the reaction solution was poured into deionized water and extracted with ethyl acetate. The organic phase was then separated, and the organic phase was obtained by rotary evaporation and elution by silica gel column chromatography.

[0050] S2. By mass, 17.4 parts of intermediate, 12.6 parts of 4-chloro-1-butene, and 60 parts of acetonitrile were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 75°C, and then the reaction was carried out at 75°C for 6 hours. After the reaction was completed, the solvent was removed by rotary evaporation to obtain the modifier.

[0051] S3. By mass, 35 parts of titanium dioxide, 10.5 parts of silane coupling agent KH-590, and 1000 parts of 40% ethanol aqueous solution were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 80°C, and then the reaction was carried out at 80°C for 4 hours. After the reaction was completed, the solid was filtered out and washed with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide.

[0052] S4. By mass, 16 parts of methyl methacrylate, 25 parts of butyl acrylate, 2.5 parts of methacrylic acid, 1.2 parts of sodium dodecyl sulfate, and 46 parts of deionized water added in the first batch are mixed in a reactor. After stirring at 4000 rpm for 6 minutes, a preemulsion is obtained. The preemulsion is then divided into two batches. 17 parts of the preemulsion added in the first batch, 0.1 parts of potassium persulfate added in the first batch, and 17 parts of deionized water added in the second batch are added to a new reactor and reacted at 82°C. After 20 minutes of polymerization, a seed emulsion was obtained. Then, 12 parts of modifier were added to the reactor, and 68 parts of pre-emulsion were added dropwise over 3 hours. 30 minutes after the start of the second batch of pre-emulsion, 4 parts of 5% potassium persulfate aqueous solution were added dropwise over 3.5 hours. After the addition was completed, the temperature was raised to 88°C and maintained for 50 minutes to complete the polymerization. After cooling, AMP-95 was added to adjust the pH of the system to 7.5, and the mixture was filtered to obtain a modified polyacrylate emulsion.

[0053] S5. By mass, add 22 parts deionized water, 1.2 parts OROTAN 731A, 0.2 parts ZH-5011, and 0.6 parts hydroxyethyl cellulose to a high-speed disperser and mix thoroughly. Then add 35 parts modified titanium dioxide and 10 parts wollastonite powder. Stir at 1400 rpm for 20 minutes, then reduce the speed to 350 rpm and add 35 parts modified polyacrylate emulsion, 2 parts Texanol, 0.6 parts SAG 622, and 0.4 parts UV-1130. After the addition is complete, continue stirring at the same speed for 15 minutes. Then add AMP-95 to adjust the pH of the system to 9. After standing and maturing, filter to remove large solid particles to obtain a light-blocking coating with high weather resistance and coating adhesion.

[0054] A light-blocking coating with high weather resistance and coating adhesion is prepared by the above preparation steps. Example

[0055] A method for preparing a light-blocking coating with high weather resistance and coating adhesion includes the following steps:

[0056] S1. By mass, 13.5 parts of isonicotinic acid, 7.5 parts of 2,2'-dithiodiethanol, 0.6 parts of p-toluenesulfonic acid, and 63 parts of N,N-dimethylformamide were mixed in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 120°C, and the reaction was carried out at 120°C for 3.5 hours. After the reaction was completed, the reaction solution was poured into deionized water and extracted with ethyl acetate. The organic phase was then separated, and the organic phase was obtained by rotary evaporation and elution by silica gel column chromatography.

[0057] S2. By mass, 14.9 parts of intermediate, 10.1 parts of 3-chloropropene, and 50 parts of acetonitrile were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 65°C. The reaction was then carried out at 65°C for 9 hours. After the reaction was completed, the solvent was removed by rotary evaporation to obtain the modifier.

[0058] S3. By mass, 30 parts of titanium dioxide, 9 parts of silane coupling agent KH-580, and 900 parts of 50% ethanol aqueous solution were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 65°C. The reaction was then carried out at 65°C for 6 hours. After the reaction was completed, the solid was filtered out and washed with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide.

[0059] S4. By mass, 13 parts methyl methacrylate, 20 parts butyl acrylate, 2 parts methacrylic acid, 0.8 parts sodium dodecylbenzenesulfonate, and 37 parts deionized water (added in the first batch) are mixed in a reactor and stirred at 3500 rpm for 8 minutes to obtain a preemulsion. The preemulsion is then divided into two batches. 13.5 parts of the preemulsion (added in the first batch), 0.075 parts of ammonium persulfate (added in the first batch), and 13.5 parts of deionized water (added in the second batch) are added to a new reactor, and the mixture is stirred at 79°C. The reaction was carried out for 25 minutes to obtain a seed emulsion. Then, 9 parts of modifier were added to the reactor, and 54 parts of pre-emulsion were added dropwise over a period of 2.5 hours. 20 minutes after the start of the second batch of pre-emulsion, 3 parts of 5% ammonium persulfate aqueous solution were added dropwise over a period of 3 hours. After the addition was completed, the temperature was raised to 86°C and the reaction was maintained at this temperature for 60 minutes to complete the polymerization. After cooling, AMP-95 was added to adjust the pH of the system to 7, and the mixture was filtered to obtain a modified polyacrylate emulsion.

[0060] S5. By weight, add 20 parts deionized water, 0.9 parts Hydropalat® 5050, 0.15 parts QHL608, and 0.4 parts hydroxyethyl cellulose to a high-speed disperser and mix thoroughly. Then add 30 parts modified titanium dioxide, 5 parts calcined kaolin, and 2.5 parts wollastonite powder. Stir at 1200 rpm for 30 minutes, then reduce the speed to 300 rpm and add 32.5 parts modified polyacrylate emulsion, 1.5 parts alcohol ester-12, 0.5 parts BYK-1786, and 0.3 parts Tinuvin 400. After the addition is complete, continue stirring at the same speed for 20 minutes. Then add AMP-95 to adjust the pH of the system to 8.5. After standing and maturing, filter to remove large solid particles to obtain a light-blocking coating with high weather resistance and coating adhesion.

[0061] A light-blocking coating with high weather resistance and coating adhesion is prepared by the above preparation steps.

[0062] Comparative Example 1

[0063] The difference between this comparative example and Example 3 is that no modifier is prepared, and butyl acrylate is used instead of butyl acrylate to prepare the polyacrylate emulsion, while the other raw materials and preparation steps remain unchanged.

[0064] A method for preparing a light-blocking coating with high weather resistance and coating adhesion includes the following steps:

[0065] S1. By mass, 30 parts of titanium dioxide, 9 parts of silane coupling agent KH-580, and 900 parts of 50% ethanol aqueous solution were mixed in a three-necked flask equipped with a condenser, thermometer, and magnetic stirrer. After turning on the magnetic stirrer, the system temperature was raised to 65°C, and then the reaction was carried out at 65°C for 6 hours. After the reaction was completed, the solid was filtered out and washed with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide.

[0066] S2. By mass, 13 parts methyl methacrylate, 20 parts butyl acrylate, 2 parts methacrylic acid, 0.8 parts sodium dodecylbenzene sulfonate, and 37 parts deionized water (added in the first batch) are mixed in a reactor and stirred at 3500 rpm for 8 minutes to obtain a preemulsion. The preemulsion is then divided into two batches. 13.5 parts of the preemulsion (added in the first batch), 0.075 parts of ammonium persulfate (added in the first batch), and 13.5 parts of deionized water (added in the second batch) are added to a new reactor, and the mixture is stirred at 79°C. The reaction was carried out for 25 min to obtain a seed emulsion. Then, 9 parts of butyl acrylate were added to the reactor, and 54 parts of the second batch of pre-emulsion were added dropwise over 2.5 h. 20 min after the start of the second batch of pre-emulsion, 3 parts of the second batch of 5% ammonium persulfate aqueous solution were added dropwise over 3 h. After the addition was completed, the temperature was raised to 86℃ and the reaction was maintained for 60 min to complete the polymerization. After cooling, AMP-95 was added to adjust the pH of the system to 7, and the mixture was filtered to obtain a polyacrylate emulsion.

[0067] S3. By weight, add 20 parts deionized water, 0.9 parts Hydropalat® 5050, 0.15 parts QHL608, and 0.4 parts hydroxyethyl cellulose to a high-speed disperser and mix thoroughly. Then add 30 parts modified titanium dioxide, 5 parts calcined kaolin, and 2.5 parts wollastonite powder. Stir at 1200 rpm for 30 minutes, then reduce the speed to 300 rpm and add 32.5 parts polyacrylate emulsion, 1.5 parts alcohol ester-12, 0.5 parts BYK-1786, and 0.3 parts Tinuvin 400. After the addition is complete, continue stirring at the same speed for 20 minutes. Then add AMP-95 to adjust the pH of the system to 8.5. After standing and maturing, filter to remove large solid particles to obtain a light-blocking coating with high weather resistance and coating adhesion.

[0068] A light-blocking coating with high weather resistance and coating adhesion is prepared by the above preparation steps.

[0069] Experimental Example 1

[0070] After curing, the high weather resistance and coating adhesion of the light-blocking coatings in Examples 1-3 and Comparative Example 1 were tested for wear resistance, heat resistance, adhesion, solvent resistance, and self-healing properties. The test results are shown in Tables 1 and 2.

[0071] Abrasion resistance test: The test was conducted in accordance with the national standard GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotary rubber grinding wheel method" and the test condition was 1000 revolutions.

[0072] Heat resistance test: The test was conducted in accordance with the national standard GB / T 9268-2008 "Test Method for Heat Resistance of Coatings", with a test temperature of 85℃ and a test time of 5 hours.

[0073] Adhesion test: The test was conducted in accordance with the national standard GB / T 9286-2021 "Cross-cut test for paint and varnish film".

[0074] Solvent resistance test: The test was conducted in accordance with the national standard GB / T 23989-2009 "Determination of Solvent Resistance of Coatings by Wiping", with ethanol as the test solvent and 200 test cycles.

[0075] Self-healing performance test: A 100μm scratch was created on the surface of each component coating using a micro-nano scratcher. The coating was then exposed to sunlight for 5 hours at a test temperature of 35℃. The self-healing performance of each component coating was then tested.

[0076] Table 1

[0077]

[0078] Table 2

[0079]

[0080] As can be seen from Tables 1 and 2, the high weather resistance and coating adhesion of the present invention has good solvent resistance, high temperature resistance, coating adhesion, and self-healing properties. Furthermore, since ambient temperature and frictional heat can accelerate the self-healing reaction of the coating, it has excellent heat resistance and wear resistance, and can still maintain good adhesion after high temperature resistance.

[0081] The descriptions of the above embodiments are merely illustrative of the methods and core ideas of the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a light-blocking coating with high weather resistance and coating adhesion, characterized in that, Includes the following steps: An intermediate was obtained by esterification of a pyridine derivative with a carboxyl group and 2,2'-dithiodiethanol. This intermediate was then reacted with a quaternary ammonium salt of a haloalkane to obtain a modifier. A silane coupling agent was grafted onto the surface of titanium dioxide to obtain modified titanium dioxide. A modified polyacrylate emulsion was then prepared using methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, initiator, modifier, and deionized water. Finally, a light-blocking coating with high weather resistance and excellent adhesion was prepared using a dispersant, wetting agent, thickener, modified titanium dioxide, filler, modified polyacrylate emulsion, film-forming aid, defoamer, UV absorber, and deionized water. Wherein, the pyridine derivative with a carboxyl group is at least one of nicotinic acid and isonicotinic acid, the halogenated hydrocarbon is at least one of 3-chloropropene and 4-chloro-1-butene, the silane coupling agent is at least one of KH-580 and KH-590, and the method for preparing the modified polyacrylate emulsion is as follows: Methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, and the first batch of deionized water were mixed and dispersed by high-speed stirring to obtain a pre-emulsion. The pre-emulsion was then divided into two parts, and the first batch of pre-emulsion, the first batch of initiator, and the second batch of deionized water were mixed and polymerized to obtain a seed emulsion. Then, a modifier, the second batch of pre-emulsion, and the second batch of initiator aqueous solution were added to the system. After polymerization was completed, the mixture was cooled, the pH was adjusted, and then filtered to obtain the final product.

2. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to claim 1, characterized in that, The conditions for esterification to occur are: The pyridine derivative with a carboxyl group, 2,2'-dithiodiethanol, and p-toluenesulfonic acid were dissolved in N,N-dimethylformamide and then reacted at a controlled temperature of 110–130 °C.

3. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to claim 1, characterized in that, The conditions for the quaternary ammonium salt reaction to occur are: The intermediate and haloalkane were dissolved in acetonitrile and then reacted under controlled temperature conditions of 55–75 °C.

4. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to claim 1, characterized in that, The method for preparing modified titanium dioxide is as follows: The product can be obtained by mixing titanium dioxide, silane coupling agent, and ethanol solution and reacting them at a controlled temperature of 50-80℃.

5. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to claim 1, characterized in that, The method for preparing a light-blocking coating with high weather resistance and coating adhesion is as follows: After mixing deionized water, dispersant, wetting agent, and thickener evenly, add modified titanium dioxide and filler. After high-speed dispersion, reduce the speed and add modified polyacrylate emulsion, film-forming aid, defoamer, and ultraviolet absorber. After the addition is complete, continue stirring for a period of time, then adjust the pH, let it stand and mature, and then filter to obtain the final product.

6. A method for preparing a light-shielding coating with high weather resistance and coating adhesion according to claims 1 to 5, characterized in that, The emulsifier is at least one of AEO-9, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate; the initiator is at least one of potassium persulfate and ammonium persulfate; the mass fraction of the aqueous solution of the second batch of initiator is 5%; the dispersant is a polyacrylate dispersant; the wetting agent is an acrylate wetting agent; the thickener is hydroxyethyl cellulose; the filler is at least one of calcined kaolin and wollastonite powder; the film-forming aid is at least one of Texanol and alcohol ester-12; the defoamer is an organosilicon defoamer; and the ultraviolet absorber is at least one of UV-1130 and Tinuvin 400.

7. A method for preparing a light-shielding coating with high weather resistance and coating adhesion according to any one of claims 1 to 5, characterized in that, The mass ratio of pyridine derivative to 2,2'-dithiodiethanol is 11.6–15.4:6.4–8.6; the mass ratio of intermediate to haloalkanes is 12.4–17.4:7.6–12.6; the mass ratio of titanium dioxide to silane coupling agent is 25–35:7.5–10.5; and the mass ratio of aqueous solutions of methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, first batch of deionized water, first batch of preemulsion, first batch of initiator, second batch of deionized water, modifier, second batch of preemulsion, and second batch of initiator is 10–1. The mass ratio of deionized water, dispersant, wetting agent, thickener, modified titanium dioxide, filler, modified polyacrylate emulsion, film-forming aid, defoamer, and ultraviolet absorber is 18-22:0.6-1.2:0.1-0.2:0.2-0.6:25-35:5-10:30-35:1-2:0.4-0.6:0.2-0.

4.

8. A method for preparing a light-shielding coating with high weather resistance and coating adhesion according to any one of claims 1 to 5, characterized in that, When preparing polyacrylate emulsion, the high-speed stirring dispersion conditions are 3000-4000 rpm and 6-10 min. When preparing a light-shielding coating with high weather resistance and coating adhesion, the high-speed dispersion conditions are 1000-1400 rpm and 20-40 min. The reduced speed conditions are 250-350 rpm. After adding all raw materials, the stirring time is continued for 15-25 min.

9. A light-blocking coating with high weather resistance and coating adhesion, characterized in that, A light-blocking coating with high weather resistance and coating adhesion is prepared by the preparation method described in any one of claims 1 to 8.

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