Shading paint with high weather resistance and coating adhesion and preparation method thereof

Abstract

The invention relates to a light-shading coating with high weather resistance and coating adhesion and a preparation method thereof, and belongs to the technical field of light-shading coatings. The modifier with disulfide bonds and polymerizable double bonds is used for modifying polyacrylate emulsion, after modification, the flexibility of polyacrylate molecular chains is remarkably improved, the curing shrinkage stress and internal stress are reduced, and the coating degree of matrix resin on hard filler is improved, so that the coating adhesive force of the opacifying paint is improved; according to the present invention, the modified polyacrylate resin can further form the stable chemical bonding between the polyacrylate resin and the titanium dioxide, provides the stable stress transfer path, and reduces the cracking and the warping of the coating, and further has the aromatic ring structure with the good heat resistance, by using the modifier disclosed by the invention, the heat resistance of the opacifying coating can be improved on the premise of not introducing an additional modifier.

Description

Technical Field

[0001] The present invention belongs to the technical field of light-shielding coatings, and in particular relates to a light-shielding coating with high weather resistance and coating adhesion and a preparation method thereof. Background Art

[0002] Sunshade coating is an important branch in the field of functional coating materials. It can effectively reflect, scatter or absorb incident light, preventing it from penetrating the coating to reach the substrate. In order to make the sunshade coating have good sunshade performance, a large amount of sunshade pigment needs to be added to the base resin. Excessive sunshade pigment particles will seriously occupy the space of the film-forming resin which serves as the "skeleton" and bonding body of the coating. This will result in insufficient resin to completely wet and cover all pigment particles, and unable to form a continuous and dense resin phase film layer between the particles. The continuity of the resin phase is destroyed and becomes fragmented. Therefore, the adhesion of the sunshade coating is generally poor. In order to solve the above technical defects, the present invention provides a sunshade coating with high weather resistance and coating adhesion and a preparation method thereof. Summary of the Invention

[0003] The object of the present invention is to provide a light-shielding coating with high weather resistance and coating adhesion and a preparation method thereof, so as to solve the problems mentioned in the above background technology.

[0004] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing a light-shielding coating with high weather resistance and coating adhesion comprises the following steps: S1. A pyridine derivative with a carboxyl group, 2,2'-dithiodiethanol, p-toluenesulfonic acid, and N,N-dimethylformamide are mixed in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, the system temperature is raised to 110-130°C, and then the reaction is carried out at a temperature of 110-130°C for 3-4 hours. After the reaction is completed, the reaction solution is poured into deionized water and extracted with ethyl acetate. The organic phase is then separated, and the organic phase is rotary evaporated and eluted by silica gel column chromatography to obtain an intermediate; S2. The intermediate, halogenated hydrocarbon, and acetonitrile are mixed in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After starting the magnetic stirring, the system temperature is raised to 55-75° C., and then the reaction is carried out at a temperature of 55-75° C. for 6-12 hours. After the reaction is completed, the solvent is removed by rotary evaporation to obtain a modifier; S3, titanium dioxide, silane coupling agent, and ethanol solution are mixed in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor, and the system temperature is raised to 50-80° C. after magnetic stirring is turned on, and then the reaction is carried out at a temperature of 50-80° C. for 4-8 hours. After the reaction is completed, the solid is filtered out and washed with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide; S4. Methyl methacrylate, butyl acrylate, methacrylic acid, an emulsifier, and the first batch of deionized water are mixed in a reactor, and the mixture is 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, and the mixture is reacted at a temperature of 76 to 82° C. for 20 to 30 minutes to obtain a seed emulsion. A modifier is then added to the reactor, and the second batch of pre-emulsion and the second batch of initiator aqueous solutions are added dropwise. After the addition is complete, the mixture is heated to 84 to 88° C. and kept warm for 50 to 70 minutes to complete the polymerization. The mixture is then cooled and a pH adjustment system is added to adjust the pH to 6.5 to 7.5, and the mixture is filtered to obtain a modified polyacrylate emulsion. S5. Add deionized water, dispersant, wetting agent and thickener into a high-speed disperser, stir and mix evenly, then add modified titanium dioxide and filler, reduce the speed after high-speed dispersion and add modified polyacrylate emulsion, film-forming aid, defoaming agent and ultraviolet absorber, keep the speed unchanged and continue stirring for a period of time after the addition is completed, then adjust the pH of the system to 8-9, let it stand and mature, and then filter to remove large particles of solid to obtain a light-shielding coating with high weather resistance and coating adhesion.

[0005] Furthermore, the pyridine derivative with a carboxyl group is at least one of nicotinic acid and isonicotinic acid.

[0006] Furthermore, the halogenated hydrocarbon is at least one of 3-chloropropylene and 4-chloro-1-butene.

[0007] Furthermore, the silane coupling agent is at least one of KH-580 and KH-590.

[0008] Furthermore, the emulsifier is at least one of AEO-9, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0009] 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%.

[0010] Furthermore, the dispersant is a polyacrylate dispersant, preferably one of OROTAN 731A and Hydropalat® 5050.

[0011] Furthermore, the wetting agent is an acrylate wetting agent, preferably one of ZH-5011 and QHL608.

[0012] Furthermore, the thickener is hydroxyethyl cellulose.

[0013] Furthermore, the filler is at least one of calcined kaolin and wollastonite powder.

[0014] Furthermore, the film-forming aid is at least one of Texanol and alcohol ester-12.

[0015] Furthermore, the defoaming agent is an organosilicon defoaming agent, preferably one of SAG 622 and BYK-1786.

[0016] Furthermore, the ultraviolet absorber is at least one of UV-1130 and Tinuvin 400.

[0017] Preferably, the pH adjuster used to adjust the pH is AMP-95.

[0018] 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.

[0019] Furthermore, the mass ratio of the intermediate, halogenated hydrocarbon, and acetonitrile in S2 is 12.4-17.4:7.6-12.6:40-60.

[0020] Furthermore, the ethanol solution used in S3 is an ethanol aqueous 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.

[0021] Furthermore, the mass ratio of the aqueous solution of methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, the first batch of deionized water, the first batch of pre-emulsion, the first batch of initiator, the second batch of deionized water, modifier, the second batch of pre-emulsion, and the 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.

[0022] Furthermore, the mass ratio of deionized water, dispersant, wetting agent, thickener, modified titanium dioxide, filler, modified polyacrylate emulsion, film-forming aid, defoaming agent 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.

[0023] Furthermore, the high-speed stirring and dispersion of the pre-emulsion in S4 is carried out at a rotation speed of 3000 to 4000 rpm and for a time of 6 to 10 minutes.

[0024] Furthermore, the time for adding the second batch of pre-emulsion in S4 is 2 to 3 hours, and the time for adding the second batch of initiator aqueous solution is 2.5 to 3.5 hours. Preferably, the second batch of initiator should be added within 10 to 30 minutes after the second batch of pre-emulsion starts to be added.

[0025] Furthermore, the speed condition for high-speed dispersion in S5 is 1000-1400 rpm, the time condition is 20-40 min, the speed condition after reduction is 250-350 rpm, and the stirring time after adding all the raw materials is continued for 15-25 min.

[0026] A light-shielding paint with high weather resistance and coating adhesion is prepared by any of the above preparation steps.

[0027] The present invention has at least one of the following beneficial effects: The present invention uses a pyridine derivative with a carboxyl group and 2,2'-dithiodiethanol as raw materials, utilizes the carboxyl group in the pyridine derivative with the alcoholic hydroxyl group in the 2,2'-dithiodiethanol to undergo an esterification reaction under the catalysis of p-toluenesulfonic acid to obtain an intermediate, and then uses the intermediate and halogenated hydrocarbon as raw materials, utilizes the pyridine structure in the intermediate and the halogen atom in the halogenated hydrocarbon to undergo a quaternary ammonium salt reaction to obtain a modifier. The modifier of the present invention has a disulfide bond and a polymerizable double bond. During the polymerization process with an acrylate monomer, the disulfide bond can be broken and reorganized under the action of an initiator, reacting with the broken sulfur free radical or double bond to reform a disulfide bond or initiate chain growth, thereby significantly improving the flexibility of the polyacrylate molecular chain, reducing curing shrinkage stress and internal stress, and increasing the degree of coverage of the matrix resin on the hard filler, thereby improving the coating adhesion of the light-shielding paint.

[0028] The modifier of the present invention can introduce heat-resistant aromatic ring structures into the main chain and side chain of the polyacrylate emulsion molecular chain after polymerization. The use of the modifier of the present invention can improve the heat resistance of the light-shielding coating without introducing additional modifiers.

[0029] The modified polyacrylate emulsion of the present invention contains disulfide bonds, and the surface of the titanium dioxide modified with a silane coupling agent is grafted with thiol groups. After the light-shielding coating is prepared, the disulfide bonds contained in the polyacrylate emulsion can undergo a reversible thiol-disulfide bond exchange reaction with the thiol groups on the surface of the titanium dioxide, forming a stable chemical bond between the polyacrylate resin and the titanium dioxide, significantly improving the interfacial stability of the light-shielding coating, thereby improving the coating adhesion of the light-shielding coating, providing a stable stress transfer path, and reducing cracking and warping of the coating. In addition, the tighter chemical bond connection can also effectively reduce the penetration of moisture, acidic media, etc. into the interface channel, thereby improving the long-term weather resistance of the coating.

[0030] The light-shielding coating of the present invention contains a dynamic self-repairing system of thiol-disulfide bonds, and the molecular chain segments have good flexibility, which can spontaneously and slowly self-repair minor internal damage. When the temperature rises, the speed of the self-repair reaction can be effectively accelerated. This self-repairing ability can effectively improve the weather resistance of the coating, reduce maintenance frequency, and extend the service life of the coating.

[0031] The light-shielding coating of the present invention contains a large amount of quaternary ammonium salt structures. The quaternary ammonium salt structures carry positive charges and can generate electrostatic attraction with uncharged or negatively charged substrates, significantly improving the adhesion of the coating. In addition, the quaternary ammonium salt structures can also form pathways within the coating for static electricity evacuation, providing certain antistatic properties, reducing electrostatic adsorption of dust on the coating surface, and keeping the coating clean and beautiful. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions of the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection requested by this application.

[0033] The sources of all raw materials in the present invention are not particularly limited and can be purchased from the market or prepared according to conventional methods known to those skilled in the art. Example

[0034] A method for preparing a light-shielding coating with high weather resistance and coating adhesion comprises the following steps: S1. Mix 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, by mass, in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the temperature of the system to 110°C, and then react at 110°C for 4 hours. After the reaction is completed, pour the reaction solution into deionized water and extract with ethyl acetate. Then, separate the organic phase, rotary evaporate the organic phase, and elute it through silica gel column chromatography to obtain the intermediate; S2. 12.4 parts of the intermediate, 7.6 parts of 3-chloropropylene, and 40 parts of acetonitrile were mixed by weight in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After starting the magnetic stirring, the system temperature was raised to 55°C, and the mixture was reacted at 55°C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation to obtain a modifier. S3. Mix 25 parts of titanium dioxide, 7.5 parts of silane coupling agent KH-590, and 800 parts of 60% ethanol aqueous solution by volume in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the temperature of the system to 50°C, and then react at 50°C for 8 hours. After the reaction is completed, filter out the solid and wash it with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide; S4. 10 parts of methyl methacrylate, 15 parts of butyl acrylate, 1.5 parts of methacrylic acid, 0.4 parts of AEO-9 and 28 parts of deionized water added in the first batch were mixed in a reactor, and stirred at 3000 rpm for 10 minutes to obtain a pre-emulsion. The pre-emulsion was then divided into two batches, and 10 parts of the pre-emulsion added in the first batch, 0.05 parts of potassium persulfate added in the first batch and 10 parts of deionized water added in the second batch were added to a new reactor, and the mixture was reacted at 76°C. The seed emulsion was polymerized for 30 minutes, and then 8 parts of the modifier was added to the reactor, and 40 parts of the second batch of pre-emulsion were added dropwise for 2 hours. 10 minutes after the start of the second batch of pre-emulsion, 2 parts of the second batch of 5% by mass potassium persulfate aqueous solution were added dropwise for 2.5 hours. After the addition was completed, the temperature was raised to 84°C and kept warm for 70 minutes to complete the polymerization. After that, the system was cooled and AMP-95 was added to adjust the pH to 6.5. The modified polyacrylate emulsion was filtered to obtain the modified polyacrylate emulsion. S5. Add 18 parts of deionized water, 0.6 parts of OROTAN 731A, 0.1 parts of ZH-5011, and 0.2 parts of hydroxyethyl cellulose into a high-speed disperser, stir and mix until evenly mixed, then add 25 parts of modified titanium dioxide and 5 parts of calcined kaolin, stir at 1000 rpm for 40 minutes, then reduce the speed to 250 rpm and add 35 parts of modified polyacrylate emulsion, 1 part of Texanol, 0.4 parts of SAG 622, and 0.2 parts of UV-1130. After the addition is complete, maintain the speed and continue stirring for 25 minutes. Then add AMP-95 to adjust the pH of the system to 8. After standing and aging, remove large particles of solid by filtration to obtain a light-shielding coating with high weather resistance and coating adhesion.

[0035] A light-shielding paint with high weather resistance and coating adhesion is prepared by the above preparation steps. Example

[0036] A method for preparing a light-shielding coating with high weather resistance and coating adhesion comprises the following steps: S1. Mix 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, by mass, in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the temperature of the system to 130°C, and then react at 130°C for 3 hours. After the reaction is completed, pour the reaction solution into deionized water and extract with ethyl acetate. Then, separate the organic phase, rotary evaporate the organic phase, and elute it through silica gel column chromatography to obtain the intermediate; S2. 17.4 parts of the 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, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, the system temperature was raised to 75°C, and the mixture was reacted at 75°C for 6 hours. After the reaction was completed, the solvent was removed by rotary evaporation to obtain a modifier. S3. Mix 35 parts of titanium dioxide, 10.5 parts of silane coupling agent KH-590, and 1000 parts of 40% by volume ethanol aqueous solution in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the temperature of the system to 80°C, and then react at 80°C for 4 hours. After the reaction is completed, filter out the solid and wash it with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide; S4. 16 parts of methyl methacrylate, 25 parts of butyl acrylate, 2.5 parts of methacrylic acid, 1.2 parts of sodium lauryl sulfate, and 46 parts of deionized water added in the first batch were mixed in a reactor, and stirred at 4000 rpm for 6 minutes to obtain a pre-emulsion. The pre-emulsion was then divided into two batches, and 17 parts of the pre-emulsion 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 were added to a new reactor, and the mixture was reacted at a temperature of 82°C. The reaction mixture was polymerized for 20 minutes to obtain a seed emulsion, and then 12 parts of a modifier were added to the reactor, and 68 parts of the second batch of pre-emulsion were added dropwise for 3 hours. 30 minutes after the start of the second batch of pre-emulsion, 4 parts of a 5% by mass potassium persulfate aqueous solution were added dropwise for 3.5 hours. After the addition was completed, the temperature was raised to 88°C and kept warm for 50 minutes to complete the polymerization. The mixture was then cooled and AMP-95 was added to adjust the pH of the system to 7.5. The modified polyacrylate emulsion was filtered to obtain the modified polyacrylate emulsion. S5. Add 22 parts of deionized water, 1.2 parts of OROTAN 731A, 0.2 parts of ZH-5011, and 0.6 parts of hydroxyethyl cellulose into a high-speed disperser, stir and mix until evenly mixed, then add 35 parts of modified titanium dioxide and 10 parts of wollastonite powder. Stir at 1400 rpm for 20 minutes, then reduce the speed to 350 rpm and add 35 parts of modified polyacrylate emulsion, 2 parts of Texanol, 0.6 parts of SAG 622, and 0.4 parts of UV-1130. After the addition is complete, maintain the speed and continue stirring for 15 minutes. Then, add AMP-95 to adjust the pH of the system to 9. After standing and aging, remove large particles of solid by filtration to obtain a light-shielding coating with high weather resistance and coating adhesion.

[0037] A light-shielding paint with high weather resistance and coating adhesion is prepared by the above preparation steps. Example

[0038] A method for preparing a light-shielding coating with high weather resistance and coating adhesion comprises the following steps: S1. Mix 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, by mass, in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the temperature of the system to 120°C, and then react at 120°C for 3.5 hours. After the reaction is completed, pour the reaction solution into deionized water and extract with ethyl acetate. Then, separate the organic phase, rotary evaporate the organic phase, and elute it through silica gel column chromatography to obtain the intermediate; S2. 14.9 parts of the intermediate, 10.1 parts of 3-chloropropylene, and 50 parts of acetonitrile were mixed by mass in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, the system temperature was raised to 65°C, and the reaction was continued at 65°C for 9 hours. After the reaction was completed, the solvent was removed by rotary evaporation to obtain a modifier; S3. Mix 30 parts of titanium dioxide, 9 parts of silane coupling agent KH-580, and 900 parts of 50% by volume ethanol aqueous solution in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the system temperature to 65°C, and then react at 65°C for 6 hours. After the reaction is completed, filter out the solid and wash it with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide; S4. 13 parts of methyl methacrylate, 20 parts of butyl acrylate, 2 parts of methacrylic acid, 0.8 parts of sodium dodecylbenzenesulfonate and 37 parts of deionized water added in the first batch were mixed in a reactor, and stirred at a speed of 3500 rpm for 8 minutes to obtain a pre-emulsion. The pre-emulsion was then divided into two batches, and 13.5 parts of the pre-emulsion 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 were added to a new reactor, and the mixture was stirred at a temperature of 79°C. The mixture was reacted under the conditions of 40 ° C for 25 minutes to obtain a seed emulsion, and then 9 parts of a modifier was added to the reactor, and 54 parts of the second batch of pre-emulsion were added dropwise for 2.5 hours. 20 minutes after the start of the second batch of pre-emulsion, 3 parts of a 5% by mass aqueous solution of ammonium persulfate were added dropwise for 3 hours. After the addition was completed, the temperature was raised to 86 ° C and kept at this temperature for 60 minutes to complete the polymerization. After that, the mixture was cooled and AMP-95 was added to adjust the pH of the system to 7, and filtered to obtain a modified polyacrylate emulsion. S5. Add 20 parts by mass of deionized water, 0.9 parts of Hydropalat® 5050, 0.15 parts of QHL608, and 0.4 parts of hydroxyethyl cellulose to a high-speed disperser. After stirring and mixing evenly, add 30 parts of modified titanium dioxide, 5 parts of calcined kaolin, and 2.5 parts of wollastonite powder. Stir at 1200 rpm for 30 minutes, then reduce the speed to 300 rpm and add 32.5 parts of modified polyacrylate emulsion, 1.5 parts of alcohol ester-12, 0.5 parts of BYK-1786, and 0.3 parts of 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 aging, remove large particles of solid by filtration to obtain a light-shielding coating with high weather resistance and coating adhesion.

[0039] A light-shielding paint with high weather resistance and coating adhesion is prepared by the above preparation steps.

[0040] Comparative Example 1 The difference between this comparative example and Example 3 is that no modifier is prepared, and butyl acrylate is used instead of the modifier to prepare the polyacrylate emulsion, and the other raw materials and preparation steps remain unchanged.

[0041] A method for preparing a light-shielding coating with high weather resistance and coating adhesion comprises the following steps: S1. Mix 30 parts of titanium dioxide, 9 parts of silane coupling agent KH-580, and 900 parts of 50% by volume ethanol aqueous solution in a three-necked flask equipped with a condenser, a thermometer, and a magnetic stirring rotor. After turning on the magnetic stirring, raise the system temperature to 65°C, and then react at 65°C for 6 hours. After the reaction is completed, filter out the solid and wash it with anhydrous ethanol and deionized water in sequence to obtain modified titanium dioxide; S2. 13 parts of methyl methacrylate, 20 parts of butyl acrylate, 2 parts of methacrylic acid, 0.8 parts of sodium dodecylbenzenesulfonate and 37 parts of deionized water added in the first batch were mixed in a reactor, and stirred at a speed of 3500 rpm for 8 minutes to obtain a pre-emulsion. The pre-emulsion was then divided into two batches, and 13.5 parts of the pre-emulsion 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 were added to a new reactor, and the mixture was stirred at a temperature of 79°C. The mixture was reacted under the conditions of 40 ° C for 25 minutes to obtain a seed emulsion, and then 9 parts of butyl acrylate was added to the reactor, and 54 parts of the second batch of pre-emulsion were added dropwise for 2.5 hours. 20 minutes after the start of the second batch of pre-emulsion, 3 parts of a 5% by mass aqueous solution of ammonium persulfate were added dropwise for 3 hours. After the addition was completed, the temperature was raised to 86 ° C and kept at this temperature for 60 minutes to complete the polymerization. After that, the mixture was cooled and AMP-95 was added to adjust the pH of the system to 7, and filtered to obtain a polyacrylate emulsion. S3. Add 20 parts by mass of deionized water, 0.9 parts of Hydropalat® 5050, 0.15 parts of QHL608, and 0.4 parts of hydroxyethyl cellulose to a high-speed disperser. After stirring and mixing evenly, add 30 parts of modified titanium dioxide, 5 parts of calcined kaolin, and 2.5 parts of wollastonite powder. Stir at 1200 rpm for 30 minutes, then reduce the speed to 300 rpm and add 32.5 parts of polyacrylate emulsion, 1.5 parts of alcohol ester-12, 0.5 parts of BYK-1786, and 0.3 parts of 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 aging, remove large particles of solid by filtration to obtain a light-shielding coating with high weather resistance and coating adhesion.

[0042] A light-shielding paint with high weather resistance and coating adhesion is prepared by the above preparation steps.

[0043] Experimental Example 1 The light-shielding coatings with high weather resistance and coating adhesion in Examples 1 to 3 and Comparative Example 1 were respectively cured and subjected to wear resistance test, heat resistance test, adhesion test, solvent resistance test, and self-repairing performance test. The test results are shown in Tables 1 and 2.

[0044] Wear resistance test: refer to the national standard GB / T 1768-2006 "Paints and varnishes - Determination of abrasion resistance - Rotating rubber grinding wheel method" for testing, and the test condition is 1000 revolutions.

[0045] Heat resistance test: The test was carried out in accordance with the national standard GB / T 9268-2008 "Test method for heat resistance of coatings", with a test temperature of 85°C and a test time of 5 hours.

[0046] Adhesion test: Test in accordance with the national standard GB / T 9286-2021 "Scratch test for paint and varnish films".

[0047] Solvent resistance test: The test was conducted in accordance with the national standard GB / T 23989-2009 "Determination of resistance to rubbing of coatings with solvents". The test solvent was ethanol and the test number was 200 times.

[0048] Self-healing performance test: A micro-nano scratch tester was used to create 100 μm scratches on the surface of each component coating. The coating was then exposed to sunlight for 5 hours at a test temperature of 35°C, and the self-healing performance of each component coating was then tested.

[0049] Table 1

[0050] Table 2

[0051] It can be seen from Tables 1 and 2 that the light-shielding coating with high weather resistance and coating adhesion of the present invention has good solvent resistance, high temperature resistance, coating adhesion, and self-repairing properties. Moreover, since the ambient temperature and friction heat can accelerate the self-repairing reaction of the coating, it has excellent heat resistance and wear resistance, and can still maintain good adhesion after high temperature resistance.

[0052] The above embodiments are intended only to facilitate understanding of the methods and core concepts 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 present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a light-shielding coating with high weather resistance and coating adhesion, characterized in that: The following steps are involved: A pyridine derivative with a carboxyl group is reacted with 2,2'-dithiodiethanol to obtain an intermediate, and the intermediate is reacted with a halogenated hydrocarbon to form a quaternary ammonium salt to obtain a modifier; a silane coupling agent is grafted onto the surface of titanium dioxide to obtain modified titanium dioxide, and then methyl methacrylate, butyl acrylate, methacrylic acid, an emulsifier, an initiator, a modifier, and deionized water are used to prepare a polyacrylate emulsion, and then a dispersant, a wetting agent, a thickener, modified titanium dioxide, a filler, a modified polyacrylate emulsion, a film-forming aid, a defoaming agent, an ultraviolet absorber, and deionized water are used to prepare a light-shielding coating with high weather resistance and coating adhesion.

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 the esterification reaction are: A pyridine derivative with a carboxyl group, 2,2'-dithiodiethanol and p-toluenesulfonic acid are dissolved in N,N-dimethylformamide and then reacted under the condition of controlling the temperature at 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 the halogenated hydrocarbon are dissolved in acetonitrile and then the reaction is carried out under the condition of controlling the temperature at 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: The product can be obtained by mixing titanium dioxide, silane coupling agent and ethanol solution and then reacting them at a temperature of 50-80°C.

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 polyacrylate emulsion is: Methyl methacrylate, butyl acrylate, methacrylic acid, an emulsifier and the first batch of deionized water are mixed and dispersed by high-speed stirring to obtain a pre-emulsion. The pre-emulsion is then divided into two parts, and the first batch of pre-emulsion, the first batch of initiator and the second batch of deionized water are mixed and polymerized to obtain a seed emulsion. A modifier, the second batch of pre-emulsion and an aqueous solution of the second batch of initiator are then added to the system, and the polymerization is completed. The mixture is cooled, the pH is adjusted and then filtered to obtain the product.

6. 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-shielding coating with high weather resistance and coating adhesion is as follows: After deionized water, dispersant, wetting agent and thickener are evenly mixed, modified titanium dioxide and filler are added. After high-speed dispersion, the speed is reduced and modified polyacrylate emulsion, film-forming aid, defoaming agent and ultraviolet absorber are added. After the addition is completed, stirring is continued for a period of time, and then the pH is adjusted. After standing and maturing, the product is filtered.

7. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to claims 1 to 6, characterized in that: 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-chloropropylene and 4-chloro-1-butene, the silane coupling agent is at least one of KH-580 and KH-590, the emulsifier is at least one of AEO-9, sodium dodecyl sulfate, and sodium dodecylbenzenesulfonate, the initiator is at least one of potassium persulfate and ammonium persulfate, the mass fraction of the initiator aqueous solution 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 a silicone defoamer, and the ultraviolet absorber is at least one of UV-1130 and Tinuvin 400.

8. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to any one of claims 1 to 6, 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 halogenated hydrocarbon 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, the mass ratio of methyl methacrylate, butyl acrylate, methacrylic acid, emulsifier, the first batch of deionized water, the first batch of pre-emulsion, the first batch of initiator, the second batch of deionized water, modifier, the second batch of pre-emulsion, and the second batch of initiator aqueous solution is 10-1 6:15~25:1.5~2.5:0.4~1.2:28~46:10~17:0.05~0.1:10~17:8~12:40~68:2~4. The mass ratio of deionized water, dispersant, wetting agent, thickener, modified titanium dioxide, filler, modified polyacrylate emulsion, film-forming aid, defoaming agent 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.

9. The method for preparing a light-shielding coating with high weather resistance and coating adhesion according to any one of claims 1 to 6, characterized in that: When preparing polyacrylate emulsion, the speed condition for high-speed stirring and dispersion is 3000-4000 rpm, and the time condition is 6-10 minutes. When preparing light-shielding coating with high weather resistance and coating adhesion, the speed condition for high-speed dispersion is 1000-1400 rpm, and the time condition is 20-40 minutes. The speed condition after reduction is 250-350 rpm. After all raw materials are added, the stirring time is continued for 15-25 minutes.

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

Images