Preparation method and application of super-weather-resistant polyester resin

Abstract

The invention relates to the field of polyester resin, in particular to a preparation method and application of super-weather-resistant polyester resin, which are used for solving the problems that the existing polyester resin is poor in weather resistance and is easily influenced by outdoor rainwater, ultraviolet rays and oxygen to cause degradation reaction, and the service life and the application effect of the polyester resin are seriously influenced. The preparation method comprises the following steps: polymerizing dihydric alcohol and dibasic acid to form the super-weather-resistant polyester resin; polyfluorine elements and hindered amine structures are introduced into the molecular structure of the polyester resin, a large number of stable C-F bonds formed by the polyfluorine elements can effectively shield ultraviolet rays and block damage of the ultraviolet rays to molecular chains, the polyester resin is endowed with excellent water resistance and corrosion resistance, and hindered amine groups can efficiently capture free radicals and inhibit oxidation and aging reactions, so that the service life of the polyester resin is prolonged, and the service life of the polyester resin is prolonged. Under the synergistic effect of the two components, the weather resistance of the prepared super-weather-resistant polyester resin is greatly improved, and the super-weather-resistant polyester resin can keep good performance for a long time in an outdoor severe environment.

Description

Technical Field

[0001] The present invention relates to the field of polyester resins, and in particular to a preparation method and application of a super-weather-resistant polyester resin. Background Art

[0002] Color-coated steel is a composite material made from metal strips using a highly automated, rapid assembly line process involving continuous cleaning, surface treatment, and coating, followed by instant high-temperature curing. It combines the ease of fabrication and molding of steel with the decorative and protective qualities of pre-fabricated steel, allowing for immediate user use. It offers excellent economic and social benefits, including replacing wood with steel, achieving efficient construction, energy conservation, and pollution prevention.

[0003] Polyester resin, as an important polymer material, is often used to prepare topcoats for color-coated panels due to its excellent overall properties, such as high strength, good processing performance, and adhesion to a variety of substrates. However, due to the structural limitations of polyester resin itself, it is easily affected by outdoor rain, ultraviolet rays, and oxygen, triggering degradation reactions. This can cause the material to exhibit problems such as yellowing, powdering, and decreased mechanical properties, seriously affecting its service life and application effect.

[0004] How to improve the weather resistance of polyester system color-coated sheets and extend the service life of color-coated sheets is the key to the present invention. Therefore, developing a preparation method and application of super weather-resistant polyester resin has important practical significance. Summary of the Invention

[0005] In order to overcome the above-mentioned technical problems, the purpose of the present invention is to provide a preparation method and application of a super weather-resistant polyester resin, which solves the problem that the existing polyester resin has poor weather resistance and is easily affected by outdoor rain, ultraviolet rays, and oxygen, causing degradation reactions, which seriously affects its service life and application effect.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A method for preparing a super weather-resistant polyester resin comprises the following steps: Add diol, dibasic acid and organic tin catalyst into the reactor, introduce nitrogen protection, stir and react for 30-40 minutes at a temperature of 100-110°C and a stirring rate of 200-300r / min, then heat the temperature to 170-180°C at a heating rate of 5-8°C and continue to stir and react for 1-2 hours, then heat the temperature to 230-240°C at a heating rate of 5-8°C and continue to stir and react for 1-2 hours, then measure the acid value every 30 minutes until the acid value is ≤6mgKOH / g, then cool the temperature to 70-80°C, add the diluent solvent and continue to stir and react for 20-30 minutes, and after the reaction is completed, cool the reaction product to room temperature to obtain a super weather-resistant polyester resin.

[0007] As a further solution of the present invention: the usage ratio of the diol, dibasic acid, organotin catalyst and dilution solvent is 280-300g:330-350g:0.4-0.5g:360-380g.

[0008] As a further solution of the present invention: the diol is a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hindered amine diol and polyfluorodiol in a mass ratio of 40-50:80-90:80-90:25-45:11-33.

[0009] As a further embodiment of the present invention, the dibasic acid is a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 80-90:105-115.

[0010] As a further solution of the present invention: the organic tin catalyst is stannous oxalate.

[0011] As a further solution of the present invention: the dilution solvent is a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 180-190:45-55.

[0012] As a further embodiment of the present invention, the hindered amine diol is prepared by the following steps: Step a1: adding cyanuric chloride, anhydrous potassium carbonate and anhydrous tetrahydrofuran to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, introducing nitrogen protection, stirring and reacting for 10-20 minutes at a temperature of 0-5°C and a stirring rate of 200-300 r / min, then adding 2,2,6,6-tetramethylpiperidinamine dropwise while stirring, controlling the dropwise acceleration rate to 2-4 mL / min, and continuing to stir and react for 20-25 hours under the condition of heating to 20-25°C after the addition is completed. After the reaction is completed, the reaction product is vacuum filtered, and the filtrate is rotary evaporated to remove the solvent, and then added to distilled water, and then extracted with ethyl acetate 2-3 times, the extracts are combined and dried over anhydrous sodium sulfate, and then vacuum filtered, and the filtrate is rotary evaporated to remove the solvent to obtain a hindered amine dichloride intermediate; Step a2: Add the hindered amine dichloride intermediate, 2-hydroxyethylamine, triethylamine and anhydrous acetone to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introduce nitrogen protection, and stir the reaction at a temperature of 20-25° C. and a stirring rate of 200-300 r / min for 30-50 minutes, then raise the temperature to 40-45° C. and continue stirring the reaction for 2-3 hours, then raise the temperature to 80-85° C. and continue stirring the reaction for 3-5 hours. After the reaction is completed, the reaction product is cooled to room temperature and then vacuum filtered. The filtrate is then poured into a sodium carbonate solution, then cooled to 0-5° C. and allowed to stand to precipitate, then vacuum filtered, and the filter cake is washed with anhydrous ethanol 2-3 times. Then, it is placed in a vacuum drying oven and dried at a temperature of 50-55° C. for 3-4 hours to obtain hindered amine diol.

[0013] As a further embodiment of the present invention: the usage ratio of the cyanuric chloride, anhydrous potassium carbonate, anhydrous tetrahydrofuran and 2,2,6,6-tetramethylpiperidinamine in step a1 is 10 mmol:11-13 mmol:50-55 mL:10 mmol.

[0014] As a further embodiment of the present invention: the hindered amine dichloride intermediate, 2-hydroxyethylamine, triethylamine and anhydrous acetone in step a2 are used in a ratio of 10 mmol: 22-25 mmol: 25-30 mmol: 60-70 mL.

[0015] As a further solution of the present invention: the mass fraction of the sodium carbonate solution in step a2 is 8-10%.

[0016] As a further embodiment of the present invention: the polyfluorodiol is prepared by the following steps: Step b1: adding cyanuric chloride, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, sodium hydroxide and anhydrous toluene to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introducing nitrogen protection, stirring and reacting at a temperature of 0-5°C and a stirring rate of 200-300 r / min for 1-2 hours, then heating to 25-30°C and continuing to stir and react for 10-15 hours. After the reaction is completed, the reaction product is rotary evaporated to remove the solvent, then added to distilled water, and then extracted with ethyl acetate 2-3 times. The extracts are combined and dried over anhydrous sodium sulfate, then vacuum filtered, and then the filtrate is rotary evaporated to remove the solvent to obtain a polyfluorodichloro intermediate; Step b2: Add the polyfluorodichloro intermediate, 2-hydroxyethylamine, triethylamine and 1,4-dioxane to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, introduce nitrogen protection, stir the reaction at a temperature of 20-25°C and a stirring rate of 200-300 r / min for 20-30 minutes, then raise the temperature to 90-100°C and continue stirring the reaction for 8-10 hours. After the reaction is completed, the reaction product is cooled to room temperature, then vacuum filtered, and then the filtrate is rotary evaporated to remove the solvent, and then purified by silica gel column chromatography using an eluent to obtain polyfluorodiol.

[0017] As a further embodiment of the present invention: the usage ratio of the cyanuric chloride, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, sodium hydroxide and anhydrous toluene in step b1 is 10 mmol: 10 mmol: 20-22 mmol: 70-80 mL.

[0018] As a further embodiment of the present invention: the usage ratio of the polyfluorodichloro intermediate, 2-hydroxyethylamine, triethylamine and 1,4-dioxane in step b2 is 10 mmol: 22-25 mmol: 30-40 mmol: 80-100 mL.

[0019] As a further solution of the present invention: the eluent in step b2 is a mixture of petroleum ether and ethyl acetate in a volume ratio of 10-15:1.

[0020] As a further solution of the present invention: use of the super weather resistant polyester resin prepared by the preparation method of the super weather resistant polyester resin in the preparation of super weather resistant polyester topcoat.

[0021] As a further embodiment of the present invention: a super weather-resistant polyester topcoat comprises the following components in parts by weight: 30-45 parts of super weather-resistant polyester resin, 6-12 parts of amino resin, 20-38 parts of pigment, 0.5-0.7 parts of dispersant, 0.5-0.7 parts of leveling agent, 0.2-0.3 parts of defoaming agent, 0.2-0.3 parts of matting agent, 0.1-0.3 parts of catalyst, 0.2-0.4 parts of wax powder, 0.1-0.5 parts of antioxidant and 15-20 parts of solvent.

[0022] As a further embodiment of the present invention: the amino resin is Yuanbang YP5625A amino resin; The pigment is one of titanium dioxide, iron oxide red, cobalt blue and cobalt green; The dispersant is BYK-110 dispersant; The leveling agent is byk381 leveling agent; The defoamer is AFCONA-2722 defoamer; The matting agent is a silicon dioxide matting agent; The catalyst is dinonylnaphthalenesulfonic acid; The wax powder is Ceridust 3910 polyamide wax; The antioxidant is antioxidant 1010; The solvent is s-150 solvent oil.

[0023] Beneficial effects of the present invention: The present invention discloses a method for preparing and applying a super-weather-resistant polyester resin, wherein the super-weather-resistant polyester resin is formed by polymerizing diols and dibasic acids; wherein the diols include neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hindered amine diols, and polyfluorodiols. By introducing polyfluorinated elements and hindered amine structures into the molecular structure of the polyester resin, the large number of stable C-F bonds formed by the polyfluorinated elements can effectively shield ultraviolet rays, preventing ultraviolet rays from damaging the molecular chain, and also imparting excellent water resistance and corrosion resistance to the resin. The hindered amine groups can efficiently capture free radicals and inhibit the progress of oxidative aging reactions. Under the synergistic effect of the two, the weather resistance of the super-weather-resistant polyester resin is greatly improved, and the resin can maintain good performance for a long time in harsh outdoor environments. The super-weather-resistant polyester resin is made into a super-weather-resistant polyester topcoat to prepare color-coated panels, which can effectively resist erosion by environmental factors such as ultraviolet rays, rain, and wind and sand, reduce fading, powdering, and peeling of the coating film, extend the service life of the color-coated panels, reduce maintenance costs, and maintain the bright color and good decorative effect of the color-coated panels.

[0024] In the process of preparing the super-weather-resistant polyester resin, a hindered amine diol is first prepared. By controlling the principle ratio and reaction temperature, a chlorine atom on cyanuric chloride reacts with the amino group on 2,2,6,6-tetramethylpiperidinamine to obtain a hindered amine dichloride intermediate. Then, the hindered amine dichloride intermediate is reacted with 2-hydroxyethylamine, and the remaining two chlorine atoms on the hindered amine dichloride intermediate react with the amino group on 2-hydroxyethylamine to obtain the hindered amine diol. The hindered amine groups in the hindered amine structure diol have a unique free radical capture ability. Under the influence of factors such as ultraviolet rays, oxygen, and heat, the polyester resin molecular chain will generate free radicals. These free radicals will trigger a chain reaction, leading to molecular chain breakage and oxidative degradation. The hindered amine groups can react with these free radicals to stabilize them and interrupt the chain transmission of the oxidation reaction, thereby effectively inhibiting the oxidation reaction, protecting the integrity of the polyester resin molecular chain, and significantly improving the weather resistance of the polyester resin.

[0025] In the process of preparing super weather-resistant polyester resin, a polyfluorodiol is first prepared. By controlling the principle ratio and reaction temperature, a chlorine atom on cyanuric chloride reacts with the hydroxyl group on 2,2,3,3,4,4,5,5-octafluoro-1-pentanol to obtain a polyfluorodichloro intermediate. Then, the polyfluorodichloro intermediate and 2-hydroxyethylamine are reacted, and the remaining two chlorine atoms on the polyfluorodichloro intermediate react with the amino group on 2-hydroxyethylamine to obtain polyfluorodiol. The fluorine element in the polyfluorodiol has extremely high electronegativity, and the formed C-F bond has high bond energy. This high bond energy makes the C-F bond react with the ultraviolet radiation. When impacted by external energy such as ultraviolet rays, it is difficult to break, which provides the polyester resin molecular chain with a layer of solid "armor", effectively blocking the erosion of ultraviolet rays and greatly reducing the risk of the molecular chain being damaged by ultraviolet rays. Moreover, the fluorine element has extremely low surface energy, and the surface of the molecular chain formed by it is highly hydrophobic and chemically inert. This makes it difficult for chemical media such as rainwater and corrosive liquids to adhere to the surface of the polyester resin in outdoor environments, reducing the contact opportunity between the chemical media and the polyester resin molecules, thereby inhibiting the occurrence of chemical reactions such as hydrolysis and oxidation, and further improving the weather resistance of the polyester resin. DETAILED DESCRIPTION

[0026] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] Example 1: This embodiment is a method for preparing a super weather-resistant polyester resin, comprising the following steps: Step s1: 10 mmol of cyanuric chloride, 11 mmol of anhydrous potassium carbonate and 50 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred and reacted for 10 minutes at a temperature of 0°C and a stirring rate of 200 r / min. Then, 10 mmol of 2,2,6,6-tetramethylpiperidinamine was added dropwise while stirring, and the dropping rate was controlled to 2 mL / min. After the addition was completed, the temperature was raised to 20°C and the stirring reaction was continued for 20 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was rotary evaporated to remove the solvent. The product was then added to distilled water, and then extracted twice with ethyl acetate. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a hindered amine dichloride intermediate. Step s2: 10 mmol of hindered amine dichloride intermediate, 22 mmol of 2-hydroxyethylamine, 25 mmol of triethylamine and 60 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at 20° C. and a stirring rate of 200 r / min for 30 minutes, and then the temperature was raised to 40° C. and the stirring reaction was continued for 2 hours. The temperature was then raised to 80° C. and the stirring reaction was continued for 3 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then poured into a sodium carbonate solution with a mass fraction of 8%, and then the temperature was lowered to 0° C. and allowed to stand to precipitate. The filter cake was then vacuum filtered, and washed twice with anhydrous ethanol. The filter cake was then placed in a vacuum drying oven and dried at 50° C. for 3 hours to obtain hindered amine diol. Step s3: 10 mmol of cyanuric chloride, 10 mmol of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 20 mmol of sodium hydroxide and 70 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 0°C and a stirring rate of 200 r / min for 1 hour, and then the temperature was raised to 25°C and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then added to distilled water, and then extracted twice with ethyl acetate. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a polyfluorodichloro intermediate; Step s4: 10 mmol of a polyfluorodichloro intermediate, 22 mmol of 2-hydroxyethylamine, 30 mmol of triethylamine, and 80 mL of 1,4-dioxane were added to a three-necked flask equipped with a stirrer, a thermometer, and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 20° C. and a stirring rate of 200 r / min for 20 minutes, and then the temperature was raised to 90° C. and the stirring reaction was continued for 8 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then rotary evaporated to remove the solvent, and then purified by silica gel column chromatography using a mixture of petroleum ether and ethyl acetate in a volume ratio of 10:1 as an eluent to obtain a polyfluorodiol; Step s5: 280g of diol, 330g of dibasic acid and 0.4g of organotin catalyst were added to the reactor, nitrogen was introduced for protection, and the reaction was stirred at a temperature of 100°C and a stirring rate of 200r / min for 30min. Then, the temperature was raised to 170°C at a heating rate of 5°C and the stirring reaction was continued for 1h. Then, the temperature was raised to 230°C at a heating rate of 5°C and the stirring reaction was continued for 1h. After that, the acid value was measured every 30min until the acid value was ≤6mgKOH / g. Then, 360g of diluent solvent was added under the condition of cooling to 70°C and stirring was continued. The reaction was carried out for 20 minutes. After the reaction was completed, the reaction product was cooled to room temperature to obtain a super weather-resistant polyester resin; wherein the diol was a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hindered amine diol and polyfluorodiol in a mass ratio of 40:80:80:25:11; wherein the dibasic acid was a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 80:105; wherein the organic tin catalyst was stannous oxalate; wherein the dilution solvent was a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 180:45.

[0028] Example 2: This example is a method for preparing a super weather-resistant polyester resin, comprising the following steps: Step s1: 10 mmol of cyanuric chloride, 12 mmol of anhydrous potassium carbonate and 52 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred for reaction at a temperature of 2° C. and a stirring rate of 250 r / min for 15 minutes. Then, 10 mmol of 2,2,6,6-tetramethylpiperidinamine was added dropwise while stirring, and the dropping rate was controlled to 3 mL / min. After the addition was completed, the temperature was raised to 22° C. and the stirring reaction was continued for 22 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was rotary evaporated to remove the solvent. The product was then added to distilled water, and then extracted twice with ethyl acetate. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a hindered amine dichloride intermediate. Step s2: 10 mmol of hindered amine dichloride intermediate, 24 mmol of 2-hydroxyethylamine, 28 mmol of triethylamine and 65 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 22° C. and a stirring rate of 250 r / min for 40 minutes, and then the temperature was raised to 42° C. and the stirring reaction was continued for 2.5 hours. The temperature was then raised to 82° C. and the stirring reaction was continued for 4 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then poured into a sodium carbonate solution with a mass fraction of 9%, and then the temperature was lowered to 3° C. and allowed to stand for precipitation. The filter cake was then vacuum filtered, and washed twice with anhydrous ethanol. The filter cake was then placed in a vacuum drying oven and dried at a temperature of 52° C. for 3.5 hours to obtain hindered amine diol. Step s3: 10 mmol of cyanuric chloride, 10 mmol of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 21 mmol of sodium hydroxide and 75 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 3° C. and a stirring rate of 250 r / min for 1.5 hours, and then the temperature was raised to 28° C. and the stirring reaction was continued for 12 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then added to distilled water, and then extracted twice with ethyl acetate. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a polyfluorodichloro intermediate; Step s4: 10 mmol of a polyfluorodichloro intermediate, 24 mmol of 2-hydroxyethylamine, 35 mmol of triethylamine, and 90 mL of 1,4-dioxane were added to a three-necked flask equipped with a stirrer, a thermometer, and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 22° C. and a stirring rate of 250 r / min for 25 minutes, and then the temperature was raised to 95° C. and the stirring reaction was continued for 9 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then rotary evaporated to remove the solvent, and then purified by silica gel column chromatography using a mixture of petroleum ether and ethyl acetate in a volume ratio of 12:1 as an eluent to obtain a polyfluorodiol; Step s5: 290g diol, 340g dibasic acid and 0.45g organotin catalyst were added to the reactor, nitrogen protection was introduced, and the reaction was stirred at a temperature of 105°C and a stirring rate of 250r / min for 35min. Then, the temperature was raised to 175°C at a heating rate of 7°C and the stirring reaction was continued for 1.5h. Then, the temperature was raised to 235°C at a heating rate of 7°C and the stirring reaction was continued for 1.5h. After that, the acid value was measured every 30min until the acid value was ≤6mgKOH / g. Then, 370g of diluted solvent was added under the condition of cooling to 75°C and the reaction was continued. The reaction was continued by stirring for 25 minutes. After the reaction was completed, the reaction product was cooled to room temperature to obtain a super weather-resistant polyester resin; wherein the diol was a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hindered amine diol and polyfluorodiol in a mass ratio of 45:85:85:35:22; wherein the dibasic acid was a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 85:110; wherein the organic tin catalyst was stannous oxalate; wherein the dilution solvent was a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 185:50.

[0029] Example 3: This example is a method for preparing a super weather-resistant polyester resin, comprising the following steps: Step s1: 10 mmol of cyanuric chloride, 13 mmol of anhydrous potassium carbonate and 55 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred and reacted for 20 minutes at a temperature of 5° C. and a stirring rate of 300 r / min. Then, 10 mmol of 2,2,6,6-tetramethylpiperidinamine was added dropwise while stirring, and the dropping rate was controlled to 4 mL / min. After the addition was completed, the temperature was raised to 25° C. and the stirring reaction was continued for 25 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was rotary evaporated to remove the solvent. The product was then added to distilled water, and then extracted with ethyl acetate three times. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a hindered amine dichloride intermediate; Step s2: 10 mmol of hindered amine dichloride intermediate, 25 mmol of 2-hydroxyethylamine, 30 mmol of triethylamine and 70 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 25° C. and a stirring rate of 300 r / min for 50 minutes, and then the temperature was raised to 45° C. and the stirring reaction was continued for 3 hours. The temperature was then raised to 85° C. and the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then poured into a sodium carbonate solution with a mass fraction of 10%, and then the temperature was lowered to 5° C. and allowed to stand for precipitation. The filter cake was then vacuum filtered. The filter cake was washed with anhydrous ethanol 3 times and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 hours to obtain hindered amine diol. Step s3: 10 mmol of cyanuric chloride, 10 mmol of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 22 mmol of sodium hydroxide and 80 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 5° C. and a stirring rate of 300 r / min for 2 hours, and then the temperature was raised to 30° C. and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then added to distilled water, and then extracted with ethyl acetate three times. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a polyfluorodichloro intermediate; Step s4: 10 mmol of a polyfluorodichloro intermediate, 25 mmol of 2-hydroxyethylamine, 40 mmol of triethylamine, and 100 mL of 1,4-dioxane were added to a three-necked flask equipped with a stirrer, a thermometer, and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 25° C. and a stirring rate of 300 r / min for 30 minutes, and then the temperature was raised to 100° C. and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then rotary evaporated to remove the solvent, and then purified by silica gel column chromatography using a mixture of petroleum ether and ethyl acetate in a volume ratio of 15:1 as an eluent to obtain a polyfluorodiol; Step s5: 300g of diol, 350g of dibasic acid and 0.5g of organotin catalyst were added to the reactor, nitrogen was introduced for protection, and the reaction was stirred at a temperature of 110°C and a stirring rate of 300r / min for 40min. Then, the temperature was raised to 180°C at a heating rate of 8°C and the stirring reaction was continued for 2h. Then, the temperature was raised to 240°C at a heating rate of 8°C and the stirring reaction was continued for 2h. After that, the acid value was measured every 30min until the acid value was ≤6mgKOH / g. Then, 380g of diluent solvent was added under the condition of cooling to 80°C and stirring was continued. The reaction was carried out for 30 minutes. After the reaction was completed, the reaction product was cooled to room temperature to obtain a super weather-resistant polyester resin; wherein the diol was a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hindered amine diol and polyfluorodiol in a mass ratio of 50:90:90:45:33; wherein the dibasic acid was a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 90:115; wherein the organic tin catalyst was stannous oxalate; wherein the dilution solvent was a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 190:55.

[0030] Example 4: This embodiment is a method for preparing a super weather-resistant polyester topcoat, comprising the following steps: According to weight parts, 30 parts of super weather-resistant polyester resin, 6 parts of amino resin, 20 parts of pigment, 0.5 parts of dispersant, 0.5 parts of leveling agent, 0.2 parts of defoaming agent, 0.2 parts of matting agent, 0.1 parts of catalyst, 0.2 parts of wax powder, 0.1 parts of antioxidant and 15 parts of solvent from Example 1 were weighed, and the above raw materials were added to a mixer, and stirred and mixed for 30 minutes at a temperature of 250° C. and a stirring rate of 800 r / min to obtain a super weather-resistant polyester topcoat. ; The amino resin is Yuanbang YP5625A amino resin; the pigment is titanium dioxide; the dispersant is BYK-110 dispersant; the leveling agent is BYK381 leveling agent; the defoaming agent is AFCONA-2722 defoaming agent; the matting agent is silica matting agent; the catalyst is dinonylnaphthalenesulfonic acid; the wax powder is Ceridust3910 polyamide wax; the antioxidant is antioxidant 1010; and the solvent is s-150 solvent oil.

[0031] Example 5: This embodiment is a method for preparing a super weather-resistant polyester topcoat, comprising the following steps: According to weight parts, 37 parts of super weather-resistant polyester resin, 9 parts of amino resin, 29 parts of pigment, 0.6 parts of dispersant, 0.6 parts of leveling agent, 0.25 parts of defoaming agent, 0.25 parts of matting agent, 0.2 parts of catalyst, 0.3 parts of wax powder, 0.3 parts of antioxidant and 18 parts of solvent from Example 2 were weighed, and the above raw materials were added to a mixer, and stirred and mixed for 30 minutes at a temperature of 250° C. and a stirring rate of 800 r / min to obtain a super weather-resistant polyester surface. paint; the amino resin is Yuanbang YP5625A amino resin; the pigment is titanium dioxide; the dispersant is BYK-110 dispersant; the leveling agent is BYK381 leveling agent; the defoaming agent is AFCONA-2722 defoaming agent; the matting agent is silica matting agent; the catalyst is dinonylnaphthalenesulfonic acid; the wax powder is Ceridust3910 polyamide wax; the antioxidant is antioxidant 1010; and the solvent is S-150 solvent oil.

[0032] Example 6: This embodiment is a method for preparing a super weather-resistant polyester topcoat, comprising the following steps: According to weight parts, 45 parts of super weather-resistant polyester resin, 12 parts of amino resin, 38 parts of pigment, 0.7 parts of dispersant, 0.7 parts of leveling agent, 0.3 parts of defoaming agent, 0.3 parts of matting agent, 0.3 parts of catalyst, 0.4 parts of wax powder, 0.5 parts of antioxidant and 20 parts of solvent from Example 3 were weighed, and the above raw materials were added to a mixer, and stirred and mixed for 30 minutes at a temperature of 250° C. and a stirring rate of 800 r / min to obtain a super weather-resistant polyester topcoat. ; The amino resin is Yuanbang YP5625A amino resin; the pigment is titanium dioxide; the dispersant is BYK-110 dispersant; the leveling agent is BYK381 leveling agent; the defoaming agent is AFCONA-2722 defoaming agent; the matting agent is silica matting agent; the catalyst is dinonylnaphthalenesulfonic acid; the wax powder is Ceridust3910 polyamide wax; the antioxidant is antioxidant 1010; and the solvent is s-150 solvent oil.

[0033] Comparative Example 1: This comparative example is a method for preparing a super-weather-resistant polyester topcoat. The difference from Example 6 is that the super-weather-resistant polyester resin used is prepared by the following steps: 300g diol, 350g dibasic acid and 0.5g organotin catalyst were added to the reactor, nitrogen was introduced for protection, and the reaction was stirred at a temperature of 110°C and a stirring rate of 300r / min for 40min. Then, the temperature was raised to 180°C at a heating rate of 8°C and the stirring reaction was continued for 2h. Then, the temperature was raised to 240°C at a heating rate of 8°C and the stirring reaction was continued for 2h. After that, the acid value was measured every 30min until the acid value was ≤6mgKOH / g. Then, 380g diluted The solvent was continued to stir and react for 30 minutes. After the reaction, the reaction product was cooled to room temperature to obtain a super weather-resistant polyester resin; wherein the diol was a mixture of neopentyl glycol, 1,6-hexanediol and 1,4-cyclohexanedimethanol in a mass ratio of 50:90:90; wherein the dibasic acid was a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 90:115; wherein the organic tin catalyst was stannous oxalate; wherein the dilution solvent was a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 190:55.

[0034] Comparative Example 2: This comparative example is a method for preparing a super-weather-resistant polyester topcoat. The difference from Example 6 is that the super-weather-resistant polyester resin used is prepared by the following steps: Step s1: 10 mmol of cyanuric chloride, 13 mmol of anhydrous potassium carbonate and 55 mL of anhydrous tetrahydrofuran were added to a three-necked flask equipped with a stirrer, a thermometer, an air guide tube and a constant pressure dropping funnel, and nitrogen was introduced for protection. The mixture was stirred and reacted for 20 minutes at a temperature of 5° C. and a stirring rate of 300 r / min. Then, 10 mmol of 2,2,6,6-tetramethylpiperidinamine was added dropwise while stirring, and the dropping rate was controlled to 4 mL / min. After the addition was completed, the temperature was raised to 25° C. and the stirring reaction was continued for 25 hours. After the reaction was completed, the reaction product was vacuum filtered, and the filtrate was rotary evaporated to remove the solvent. The product was then added to distilled water, and then extracted with ethyl acetate three times. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was rotary evaporated to remove the solvent to obtain a hindered amine dichloride intermediate; Step s2: 10 mmol of hindered amine dichloride intermediate, 25 mmol of 2-hydroxyethylamine, 30 mmol of triethylamine and 70 mL of anhydrous acetone were added to a three-necked flask equipped with a stirrer, a thermometer and an air guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 25° C. and a stirring rate of 300 r / min for 50 minutes, and then the temperature was raised to 45° C. and the stirring reaction was continued for 3 hours. The temperature was then raised to 85° C. and the stirring reaction was continued for 5 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then poured into a sodium carbonate solution with a mass fraction of 10%, and then the temperature was lowered to 5° C. and allowed to stand for precipitation. The filter cake was then vacuum filtered. The filter cake was washed with anhydrous ethanol 3 times and then placed in a vacuum drying oven and dried at a temperature of 55° C. for 4 hours to obtain hindered amine diol. Step s3: 300g of diol, 350g of dibasic acid and 0.5g of organotin catalyst were added to the reactor, nitrogen was introduced for protection, and the reaction was stirred at a temperature of 110°C and a stirring rate of 300r / min for 40min. Then, the temperature was raised to 180°C at a heating rate of 8°C and the stirring reaction was continued for 2h. Then, the temperature was raised to 240°C at a heating rate of 8°C and the stirring reaction was continued for 2h. After that, the acid value was measured every 30min until the acid value was ≤6mgKOH / g. Then, 380g of dilution solvent was added under the condition of cooling to 80°C. The reaction was continued with stirring for 30 minutes. After the reaction was completed, the reaction product was cooled to room temperature to obtain a super weather-resistant polyester resin; wherein the diol was a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and hindered amine diol in a mass ratio of 50:90:90:45; wherein the dibasic acid was a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 90:115; wherein the organic tin catalyst was stannous oxalate; wherein the dilution solvent was a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 190:55.

[0035] Comparative Example 3: This comparative example is a method for preparing a super-weather-resistant polyester topcoat. The difference from Example 6 is that the super-weather-resistant polyester resin used is prepared by the following steps: Step s1: 10 mmol of cyanuric chloride, 10 mmol of 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, 22 mmol of sodium hydroxide and 80 mL of anhydrous toluene were added to a three-necked flask equipped with a stirrer, a thermometer and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at a temperature of 5° C. and a stirring rate of 300 r / min for 2 hours, and then the temperature was raised to 30° C. and the stirring reaction was continued for 15 hours. After the reaction was completed, the reaction product was rotary evaporated to remove the solvent, and then added to distilled water, and then extracted with ethyl acetate three times. The extracts were combined and dried over anhydrous sodium sulfate, and then vacuum filtered. The filtrate was then rotary evaporated to remove the solvent to obtain a polyfluorodichloro intermediate; Step s2: 10 mmol of a polyfluorodichloro intermediate, 25 mmol of 2-hydroxyethylamine, 40 mmol of triethylamine, and 100 mL of 1,4-dioxane were added to a three-necked flask equipped with a stirrer, a thermometer, and a gas guide tube, and nitrogen was introduced for protection. The mixture was stirred at 25° C. and a stirring rate of 300 r / min for 30 minutes, and then the temperature was raised to 100° C. and the stirring reaction was continued for 10 hours. After the reaction was completed, the reaction product was cooled to room temperature and then vacuum filtered. The filtrate was then rotary evaporated to remove the solvent, and then purified by silica gel column chromatography using a mixture of petroleum ether and ethyl acetate in a volume ratio of 15:1 as an eluent to obtain a polyfluorodiol; Step s3: 300g diol, 350g dibasic acid and 0.5g organotin catalyst were added to the reactor, nitrogen was introduced for protection, and the reaction was stirred at a temperature of 110°C and a stirring rate of 300r / min for 40min. Then, the temperature was raised to 180°C at a heating rate of 8°C and the stirring reaction was continued for 2h. Then, the temperature was raised to 240°C at a heating rate of 8°C and the stirring reaction was continued for 2h. After that, the acid value was measured every 30min until the acid value was ≤6mgKOH / g. Then, 380g diluted solution was added under the condition of cooling to 80°C. The agent is stirred and reacted for 30 minutes. After the reaction, the reaction product is cooled to room temperature to obtain a super weather-resistant polyester resin; wherein the diol is a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and polyfluorodiol in a mass ratio of 50:90:90:33; wherein the dibasic acid is a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 90:115; wherein the organic tin catalyst is stannous oxalate; wherein the dilution solvent is a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 190:55.

[0036] Performance Testing The super-weather-resistant polyester topcoat of Examples 4-6 and Comparative Examples 1-3 was sprayed on a steel plate whose surface had been wiped with alcohol and naturally drained. The plate was allowed to stand at 25°C for 10 minutes, then placed in a vacuum drying oven and dried at 180°C for 30 minutes. The plate was then naturally cooled for 6 hours. The coating film with a thickness of 15 μm was tested in the following manner: QUVA and QUVB tests are conducted according to ASTM G154, gloss retention and color difference are tested according to GB / T 13448-2019, and chalking grade is tested according to GB / T1766-2008.

[0037] The test results are shown in the following table: .

[0038] Referring to the data in the above table, based on the comparison between Examples 4-6 and Comparative Examples 1-3, it can be seen that the super weather-resistant polyester topcoat of the present application has excellent weather resistance, and it also shows that the super weather-resistant polyester resin in the present application has excellent super weather resistance.

[0039] Throughout this specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0040] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a super weather-resistant polyester resin, characterized in that: The following steps are involved: Add diol, dibasic acid and organotin catalyst into a reactor, introduce nitrogen protection, stir and react for 30-40 minutes at a temperature of 100-110° C. and a stirring rate of 200-300 r / min, then heat the temperature to 170-180° C. at a heating rate of 5-8° C. and continue to stir and react for 1-2 hours, then heat the temperature to 230-240° C. at a heating rate of 5-8° C. and continue to stir and react for 1-2 hours, then measure the acid value every 30 minutes until the acid value is ≤6 mgKOH / g, then cool the temperature to 70-80° C., add a diluent solvent and continue to stir and react for 20-30 minutes, and after the reaction, cool the reaction product to room temperature to obtain a super weather-resistant polyester resin; The usage ratio of the diol, dibasic acid, organotin catalyst and dilution solvent is 280-300g:330-350g:0.4-0.5g:360-380g; The diol is a mixture of neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, hindered amine diol and polyfluorodiol in a mass ratio of 40-50:80-90:80-90:25-45:11-33; The dibasic acid is a mixture of adipic acid and hexahydrophthalic anhydride in a mass ratio of 80-90:105-115; The organotin catalyst is stannous oxalate; The dilution solvent is a mixture of S100 solvent oil and propylene glycol methyl ether acetate in a mass ratio of 180-190:45-55.

2. The method for preparing a super weather-resistant polyester resin according to claim 1, wherein: The hindered amine diol is prepared by the following steps: Step a1: stirring cyanuric chloride, anhydrous potassium carbonate and anhydrous tetrahydrofuran to react, then adding 2,2,6,6-tetramethylpiperidinamine and continuing stirring to react, after the reaction is completed, vacuum filtering the reaction product, then rotary evaporating the filtrate, then adding it to distilled water, then extracting, and drying the extract, then vacuum filtering, and then rotary evaporating the filtrate to obtain a hindered amine dichloride intermediate; Step a2: Stirring the hindered amine dichloride intermediate, 2-hydroxyethylamine, triethylamine, and anhydrous acetone to react. After the reaction is completed, the reaction product is cooled and then vacuum filtered. The filtrate is then poured into a sodium carbonate solution and allowed to stand to precipitate. The precipitate is then vacuum filtered, and the filter cake is washed and dried to obtain a hindered amine diol.

3. The method for preparing a super weather-resistant polyester resin according to claim 2, wherein: The usage ratio of the cyanuric chloride, anhydrous potassium carbonate, anhydrous tetrahydrofuran and 2,2,6,6-tetramethylpiperidinamine in step a1 is 10 mmol:11-13 mmol:50-55 mL:10 mmol.

4. The method for preparing a super weather-resistant polyester resin according to claim 2, wherein: The hindered amine dichloride intermediate, 2-hydroxyethylamine, triethylamine and anhydrous acetone in step a2 are used in a ratio of 10 mmol: 22-25 mmol: 25-30 mmol: 60-70 mL; and the mass fraction of the sodium carbonate solution is 8-10%.

5. The method for preparing a super weather-resistant polyester resin according to claim 1, wherein: The polyfluorodiol is prepared by the following steps: Step b1: stirring cyanuric chloride, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, sodium hydroxide and anhydrous toluene, rotary evaporating the reaction product after the reaction, then adding it to distilled water, extracting it, and drying the extract. After vacuum filtration, the filtrate is rotary evaporated to obtain a polyfluorodichloro intermediate; Step b2: stirring the polyfluorodichloro intermediate, 2-hydroxyethylamine, triethylamine and 1,4-dioxane to react. After the reaction is completed, the reaction product is cooled and then vacuum filtered. The filtrate is then rotary evaporated and purified by silica gel column chromatography to obtain polyfluorodiol.

6. The method for preparing a super weather-resistant polyester resin according to claim 5, wherein: The usage ratio of the cyanuric chloride, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, sodium hydroxide and anhydrous toluene in step b1 is 10 mmol: 10 mmol: 20-22 mmol: 70-80 mL.

7. The method for preparing a super weather-resistant polyester resin according to claim 5, characterized in that: The usage ratio of the polyfluorodichloro intermediate, 2-hydroxyethylamine, triethylamine and 1,4-dioxane in step b2 is 10 mmol: 22-25 mmol: 30-40 mmol: 80-100 mL.

8. Use of the super weather resistant polyester resin prepared by the method for preparing the super weather resistant polyester resin according to any one of claims 1 to 7 in preparing a super weather resistant polyester topcoat.

9. A super weather-resistant polyester topcoat as claimed in claim 8, characterized in that: It comprises the following components in parts by weight: 30-45 parts of super weather-resistant polyester resin, 6-12 parts of amino resin, 20-38 parts of pigment, 0.5-0.7 parts of dispersant, 0.5-0.7 parts of leveling agent, 0.2-0.3 parts of defoaming agent, 0.2-0.3 parts of matting agent, 0.1-0.3 parts of catalyst, 0.2-0.4 parts of wax powder, 0.1-0.5 parts of antioxidant and 15-20 parts of solvent.

10. The super weather-resistant polyester topcoat according to claim 9, characterized in that: The amino resin is Yuanbang YP5625A amino resin; The pigment is one of titanium dioxide, iron oxide red, cobalt blue and cobalt green; The dispersant is BYK-110 dispersant; The leveling agent is byk381 leveling agent; The defoamer is AFCONA-2722 defoamer; The matting agent is a silicon dioxide matting agent; The catalyst is dinonylnaphthalenesulfonic acid; The wax powder is Ceridust 3910 polyamide wax; The antioxidant is antioxidant 1010; The solvent is s-150 solvent oil.