Polyester curing agent, polyester curing agent modified water-based acrylic acid anticorrosive paint and preparation method of polyester curing agent modified water-based acrylic acid anticorrosive paint

Abstract

The invention discloses a polyester curing agent, a polyester curing agent modified water-based acrylic acid anticorrosive paint and a preparation method thereof, and relates to the technical field of paints. According to the prepared polyester curing agent and polyester curing agent modified water-based acrylic acid anticorrosive paint, the polyester curing agent is prepared by reacting polymaleic anhydride resin with hexane oxide adipate, and the polymaleic anhydride resin is prepared by reacting maleic anhydride with trimethylpropane trimethacrylate; the adipic acid epoxy cyclohexane ester is prepared by reaction of epoxy cyclohexane and oxalic acid, so that the coating has high compactness after being coated to form a film, the mechanical property of the coating is enhanced, the polymer microspheres are prepared by reaction of amino polystyrene microspheres and sulfydryl cyclodextrin, the mechanical strength and penetration resistance of the coating are enhanced, and the service life of the coating is prolonged. Therefore, the anti-corrosion performance of the paint is comprehensively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a polyester curing agent, a polyester curing agent-modified water-based acrylic anti-corrosion coating and a preparation method thereof. Background Art

[0002] Anti-corrosion coatings are generally divided into conventional anti-corrosion coatings and heavy-duty anti-corrosion coatings, and are an indispensable type of coating among paints and coatings. Conventional anti-corrosion coatings, under normal conditions, play an anti-corrosion role on metals and other materials, protecting the service life of non-ferrous metals; heavy-duty anti-corrosion coatings refer to a type of anti-corrosion coating that can be used in relatively harsh corrosive environments and has a longer protection period than conventional anti-corrosion coatings. Heavy-duty anti-corrosion coatings are generally used in emerging marine engineering such as offshore facilities, coastal and bay structures, modern transportation such as highway guardrails and bridges, and large industrial enterprises such as food and chemical equipment, the inner and outer walls of metal containers, chemicals, steel and other fields.

[0003] The curing agent of water-based acrylic anti-corrosion coating is a key component for optimizing its performance, which directly affects the cross-linking density, chemical resistance, mechanical strength and construction applicability of the coating. In the prior art, the curing agents of water-based acrylic anti-corrosion coatings often include isocyanates, aziridines, carbodiimides, epoxies, etc. The anti-corrosion performance of water-based anti-corrosion coatings depends on the corrosion resistance of the matrix resin itself on the one hand, and on the auxiliary performance of the pigments, fillers and additives added thereto on the other hand. Since the traditional solvent-based coating technology is mature, the compatibility and stability technology of the various additives used and the system is also relatively mature. However, the anti-corrosion performance of the water-based coatings to be used in the future development trend still needs to be improved. Therefore, the present invention studies and prepares a polyester curing agent with excellent anti-corrosion performance and a water-based acrylic anti-corrosion coating modified with a polyester curing agent. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a polyester curing agent, a polyester curing agent-modified water-based acrylic anti-corrosion coating and a preparation method thereof.

[0005] The present invention proposes a technical solution to solve the above technical problems: a polyester curing agent, wherein the polyester curing agent is prepared by the reaction of polymaleic anhydride resin and epoxy cyclohexane adipate; the polymaleic anhydride resin is prepared by the reaction of maleic anhydride and trimethylolpropane trimethacrylate; and the epoxy cyclohexane adipate is prepared by the reaction of epoxy cyclohexane and oxalic acid.

[0006] A polyester curing agent-modified water-based acrylic anti-corrosion coating comprises water-based hydroxy acrylic acid, polyester curing agent, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water.

[0007] Preferably, the polymer microspheres are prepared by reacting aminopolystyrene microspheres with mercaptocyclodextrin.

[0008] Preferably, the filler is calcium carbonate; the dispersant is oxidized polyethylene wax; the film-forming agent is propylene glycol phenyl ether; the defoamer is BYK-022; the leveling agent is BYK-333; and the rust inhibitor is alkenyl succinate.

[0009] A method for preparing a polyester curing agent-modified water-based acrylic anti-corrosion coating comprises the following specific steps: S1. Under a nitrogen atmosphere, polymaleic anhydride resin and acetone were mixed in a mass ratio of 1:6-8. After sufficient swelling, 1.3-1.5 times the mass of polymaleic anhydride resin epoxycyclohexane adipate and 0.02-0.04 times the mass of polymaleic anhydride resin catalyst triethylamine were added. The temperature was raised to 120-150°C, the reaction was carried out for 4-6 hours, and the polyester curing agent was obtained by vacuum rotary evaporation. S2. Aminopolystyrene microspheres, mercaptocyclodextrin, and deionized water were mixed in a mass ratio of 1.2-1.3:1:30-50, stirred, and heated to 60-70°C. Thiophosgene (0.06-0.08 times the mass of the aminopolystyrene microspheres) was added and reacted for 3-5 hours. The mixture was filtered, washed with deionized water 3-5 times, and dried to produce polymer microspheres. S3. Mix water-based hydroxy acrylic acid and dispersant, stir evenly and heat to 70~80℃, add polymer microspheres, filler and rust inhibitor, stir at 500~600rpm for 30~50min, cool to room temperature, add polyester curing agent, defoaming agent, leveling agent and deionized water, and continue stirring for 30~50min. The mass ratio of water-based hydroxy acrylic acid, polyester curing agent, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water is 50~60:1~2:4~8:2~4:0.5~1.5:0.5~1.5:1~2:0.5~1.5:1~2:10~20 to prepare polyester curing agent and polyester curing agent modified water-based acrylic anti-corrosion coating.

[0010] Preferably, in the above step S1, the preparation method of terminal hydroxy butyl acrylate is: under a nitrogen atmosphere, butyl acrylate, azobisisobutyronitrile, mercaptoethanol and toluene are mixed in a mass ratio of 100:1:1~5:40, the temperature is raised to 60~62°C, the reaction is carried out for 30~40 minutes, the reaction is terminated with petroleum ether, the mixture is washed with deionized water 3~5 times, and vacuum dried at 80~90°C to obtain terminal hydroxy butyl acrylate.

[0011] Preferably, in the above step S1, the preparation method of epoxy cyclohexane adipate is: under a nitrogen atmosphere, epoxy cyclohexane, oxalic acid and catalyst tetrabutyl titanate are mixed in a molar ratio of 2~2.2:1:0.02~0.04, the temperature is raised to 65~75°C, and the reaction is kept warm for 2~3h to obtain epoxy cyclohexane adipate.

[0012] Preferably, in the above step S1, the preparation method of the polymaleic anhydride resin is: under a nitrogen atmosphere, maleic anhydride, butanone and n-butane are mixed in a mass ratio of 0.8~1.2:4:6, stirred evenly, and then trimethylolpropane trimethacrylate (3.1~3.3 times the mass of maleic anhydride) and azoisobutyronitrile (0.006~0.008 times the mass of maleic anhydride) are added, the temperature is raised to 68~72°C, the reaction is carried out for 6~8h, the mixture is filtered and extracted with acetone Soxhlet for 48h to obtain the polymaleic anhydride resin.

[0013] Preferably, in the above step S2, the preparation method of amino polystyrene microspheres is: polystyrene microspheres and deionized water are mixed in a mass ratio of 1:10~12, stirred evenly, and added with stirring at 800~1200 rpm. The mixed acid is 2~4 times the mass of the polystyrene microspheres, and the volume ratio of concentrated sulfuric acid to 20~30% nitric acid in the mixed acid is 3:2. The mixture is reacted for 1~2 hours, filtered and washed with deionized water 3~5 times, transferred to 20~30 times the mass of polystyrene microspheres. 2 mol / L sodium hydroxide solution, heated to 76~78 ° C, and then 0.1~0.3 times the mass of the polystyrene microspheres. Sodium dithionite, a reducing agent, is added, reacted for 3~4 hours, filtered and washed with deionized water 3~5 times, and dried to obtain amino polystyrene microspheres.

[0014] Preferably, the preparation method of the polystyrene microspheres is: mixing the stabilizer polyvinyl pyrrolidone, ethanol and deionized water in a mass ratio of 1:8 to 10:50, stirring evenly, adding 0.02 to 0.04 times the mass of polyvinyl pyrrolidone of azobisisobutyronitrile and 2 to 4 times the mass of polyvinyl pyrrolidone of polystyrene, heating to 68 to 72° C., passing nitrogen at a rate of 1 to 5 m / s for 12 to 14 hours, centrifuging and washing with anhydrous ethanol 3 to 5 times, and finally rotary evaporation to dryness to obtain polystyrene microspheres.

[0015] Preferably, in the above step S2, the preparation method of mercaptocyclodextrin is as follows: β-cyclodextrin, sodium hydroxide and deionized water are mixed in a mass ratio of 1:0.1:10~12, stirred evenly, and a p-toluenesulfonyl chloride solution of equal mass of β-cyclodextrin is added dropwise at a rate of 1~3 ml / min, wherein the mass ratio of p-toluenesulfonyl chloride and acetonitrile in the p-toluenesulfonyl chloride solution is 8:0.8~1.2, stirred at 1000~1200 rpm for 2~4 hours, centrifuged and allowed to stand for 12~24 hours, filtered and recrystallized with deionized water, and transferred to β-cyclodextrin. The method comprises the following steps: a thiourea solution with a mass ratio of thiourea, methanol and deionized water of 1.5:4:1-2 is prepared by heating to 85-88°C, reacting under reflux for 48 hours, washing with anhydrous methanol 3-5 times after rotary evaporation, dissolving with a sodium hydroxide solution with a mass fraction of 10-12%, heating to 45-55°C, reacting for 5-6 hours, adjusting the pH to 1.8-2.2 with hydrochloric acid, adding trichloroethylene with a mass ratio of 0.02-0.04 times the mass of β-cyclodextrin, reacting at room temperature for 24 hours, filtering and drying to obtain thiol cyclodextrin.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The polyester curing agent and polyester curing agent modified water-based acrylic anti-corrosion coating prepared by the present invention use water-based hydroxy acrylic acid as a film-forming substance, and are added with polyester curing agent and polymer microspheres; The polyester curing agent is prepared by the reaction of polymaleic anhydride resin and epoxycyclohexane adipate. The polymaleic anhydride resin is prepared by the reaction of maleic anhydride and trimethylolpropane trimethacrylate. The epoxycyclohexane adipate is prepared by the reaction of epoxycyclohexane and oxalic acid. Maleic anhydride and trimethylolpropane trimethacrylate react to form a polymaleic anhydride resin with a three-dimensional network structure, which then reacts with epoxycyclohexane adipate to form a polyester curing agent with cross-linking properties. The polyester curing agent is introduced into water-based hydroxy acrylic acid to form a dense cross-linking network, making the coating highly dense after film formation, thereby enhancing the mechanical properties of the coating. The polymer microspheres are prepared by the reaction of amino polystyrene microspheres and mercaptocyclodextrin. The amino polystyrene microspheres with excellent mechanical properties are introduced and react with mercaptocyclodextrin to form thiourea in the coating, which not only enhances the interaction between the polymer microspheres and the water-based hydroxy acrylic resin, but also improves the chemical corrosion resistance of the coating. The cavity structure of mercaptocyclodextrin can adsorb and fix some small molecular corrosive media, further enhancing the anti-corrosion effect of the coating. The introduction of polymer microspheres enables the coating to form a more complex and dense microstructure during the film-forming process. This structure is beneficial to enhancing the mechanical strength and anti-permeability of the coating, thereby comprehensively improving the anti-corrosion performance of the coating. DETAILED DESCRIPTION

[0017] The present invention is described in detail below through examples. It should be noted that the following examples are intended only to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Those skilled in the art may make non-essential improvements and adjustments to the present invention based on the above disclosure. Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art.

[0018] The water-based hydroxylated acrylic acid used in this embodiment and the comparative example was purchased from Guangzhou Lvbao New Materials Co., Ltd. The model number was PT-2043, with a solid content of 44% and a hydroxyl value of 4.3%.

[0019] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the various index test methods of the polyester curing agent and the polyester curing agent-modified water-based acrylic anti-corrosion coating prepared in the examples and comparative examples as follows: Salt spray resistance: The polyester curing agent and the polyester curing agent-modified water-based acrylic anti-corrosion coatings of the examples and comparative examples were subjected to a salt spray resistance test with reference to GB / T 1771.

[0020] Alkali resistance: The polyester curing agent and polyester curing agent-modified water-based acrylic anti-corrosion coatings of the examples and comparative examples were coated in the same manner and immersed in a 0.1M sodium hydroxide solution at room temperature for 24 hours to observe whether bubbles fell off.

[0021] Mechanical properties: The polyester curing agent and polyester curing agent-modified water-based acrylic anti-corrosion coatings of the examples and comparative examples were subjected to hardness tests according to GB / T 6739.

[0022] Example 1 The preparation method of the water-based acrylic anticorrosive coating modified with a polyester curing agent in this embodiment is as follows: S1. Under a nitrogen atmosphere, epoxy cyclohexane, oxalic acid and catalyst tetrabutyl titanate were mixed in a molar ratio of 2:1:0.02, heated to 65 ° C, and kept warm for 2 hours to obtain epoxy cyclohexane adipate; under a nitrogen atmosphere, maleic anhydride, butanone and n-butane were mixed in a mass ratio of 0.8:4:6, stirred evenly, and then trimethylolpropane trimethacrylate (3.1 times the mass of maleic anhydride) and 0.006 times the mass of maleic anhydride were added. The reaction mixture was stirred for 4 hours, and the mixture was heated to 68°C for 6 hours, filtered and extracted with acetone Soxhlet for 48 hours to obtain a polymaleic anhydride resin; under a nitrogen atmosphere, the polymaleic anhydride resin was mixed with acetone in a mass ratio of 1:6, and after sufficient swelling, 1.3 times the mass of the polymaleic anhydride resin epoxycyclohexane and 0.02 times the mass of the polymaleic anhydride resin catalyst triethylamine were added, the mixture was heated to 120°C for 4 hours, and vacuum rotary evaporation was performed to obtain a polyester curing agent; S2. The stabilizer polyvinyl pyrrolidone, ethanol and deionized water were mixed in a mass ratio of 1:8:50, stirred evenly, and then 0.02 times the mass of polyvinyl pyrrolidone and 2 times the mass of polystyrene were added. The temperature was raised to 68 ° C, nitrogen was passed through at a rate of 1m / s for 12h, centrifuged and washed with anhydrous ethanol three times, and finally evaporated to dryness to obtain polystyrene microspheres; polystyrene microspheres and deionized water were mixed in a mass ratio of 1:10, stirred evenly, and polystyrene microspheres were added under stirring at 800rpm. The mixture was stirred for 1 h, filtered and washed 3 times with deionized water, and then transferred to a 2 mol / L sodium hydroxide solution 20 times the mass of the polystyrene microspheres. The mixture was heated to 76 ° C, and then sodium dithionite, a reducing agent 0.1 times the mass of the polystyrene microspheres, was added. The mixture was reacted for 3 h, filtered and washed 3 times with deionized water, and dried to obtain amino polystyrene microspheres. β-cyclodextrin, sodium hydroxide and deionized water were mixed in a mass ratio of 1:0.1:10 and stirred. After homogenization, a p-toluenesulfonyl chloride solution of equal mass to β-cyclodextrin was added dropwise at a rate of 1 ml / min. The mass ratio of p-toluenesulfonyl chloride and acetonitrile in the p-toluenesulfonyl chloride solution was 8:0.8. The mixture was stirred at 1000 rpm for 2 h, centrifuged and allowed to stand for 12 h, filtered and recrystallized with deionized water, and transferred to a thiourea solution of 1.2 times the mass of β-cyclodextrin. The mass ratio of thiourea, methanol and deionized water in the thiourea solution was 1.5:4:1. The mixture was heated to 85°C and refluxed for 48 h. After rotary evaporation, the mixture was washed three times with anhydrous methanol and then mass-reacted. The mixture was dissolved in 10% sodium hydroxide solution, heated to 45°C, reacted for 5 hours, adjusted to pH 1.8 with hydrochloric acid, and then added with trichloroethylene (0.02 times the mass of β-cyclodextrin), reacted at room temperature for 24 hours, filtered and dried to obtain thiol cyclodextrin. Amino polystyrene microspheres, thiol cyclodextrin and deionized water were mixed in a mass ratio of 1.2:1:30, stirred evenly, heated to 60°C, and 0.06 times the mass of amino polystyrene microspheres were added with thiophosgene (0.06 times the mass of amino polystyrene microspheres), reacted for 3 hours, filtered and washed with deionized water 3 times, and dried to obtain polymer microspheres. S3. Mix water-based hydroxy acrylic acid and dispersant, stir evenly and heat to 70°C, add polymer microspheres, filler and rust inhibitor, stir at 500 rpm for 30 minutes, cool to room temperature, add polyester curing agent, defoaming agent, leveling agent and deionized water, and continue stirring for 30 minutes. The mass ratio of water-based hydroxy acrylic acid, polyester curing agent, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water is 50:1:4:2:0.5:0.5:1:0.5:1:10 to obtain polyester curing agent and polyester curing agent modified water-based acrylic anti-corrosion coating.

[0023] Example 2 The preparation method of the water-based acrylic anticorrosive coating modified with a polyester curing agent in this embodiment is as follows: S1. Under a nitrogen atmosphere, epoxy cyclohexane, oxalic acid and catalyst tetrabutyl titanate were mixed in a molar ratio of 2.1:1:0.03, heated to 70 ° C, and kept warm for 2.5 hours to obtain epoxy cyclohexane adipate; under a nitrogen atmosphere, maleic anhydride, butanone and n-butane were mixed in a mass ratio of 1:4:6, stirred evenly, and then 3.2 times the mass of maleic anhydride trimethylolpropane trimethacrylate and 0.007 times the mass of maleic anhydride were added. Azoisobutyronitrile was heated to 70°C, reacted for 7 hours, filtered and extracted with acetone Soxhlet for 48 hours to obtain polymaleic anhydride resin; under a nitrogen atmosphere, polymaleic anhydride resin and acetone were mixed in a mass ratio of 1:7, and after sufficient swelling, 1.4 times the mass of polymaleic anhydride resin epoxycyclohexane and 0.03 times the mass of polymaleic anhydride resin catalyst triethylamine were added, the temperature was raised to 140°C, reacted for 5 hours, and vacuum rotary evaporation was performed to obtain a polyester curing agent; S2. The stabilizer polyvinyl pyrrolidone, ethanol and deionized water were mixed in a mass ratio of 1:9:50, stirred evenly, and then 0.03 times the mass of polyvinyl pyrrolidone and 3 times the mass of polystyrene were added. The temperature was raised to 70 ° C, nitrogen was passed through at a rate of 4m / s for 13h, centrifuged and washed 4 times with anhydrous ethanol, and finally evaporated to dryness to obtain polystyrene microspheres; polystyrene microspheres and deionized water were mixed in a mass ratio of 1:11, stirred evenly, and polystyrene microspheres were added under stirring at 1000rpm. The mixture was stirred for 1 h, and the reaction mixture was stirred for 1 h. The mixture was stirred for 1 h. The mixture was stirred for 1 h. The mixture was stirred for 1 h. The mixture was stirred for 2 h. The mixture was stirred for 3 h. The volume ratio of concentrated sulfuric acid to 250% nitric acid was 3:2. The mixture was reacted for 1.5 h. The mixture was filtered and washed with deionized water 4 times. The mixture was transferred to a 2 mol / L sodium hydroxide solution 25 times the mass of the polystyrene microspheres. The mixture was heated to 77 ° C. Then, the reducing agent sodium dithionite was added in an amount of 0.2 times the mass of the polystyrene microspheres. The mixture was reacted for 3.5 h. The mixture was filtered and washed with deionized water 4 times. The mixture was dried to obtain amino polystyrene microspheres. β-cyclodextrin, sodium hydroxide and deionized water were mixed in a mass ratio of 1:0.1:11. After stirring evenly, add p-toluenesulfonyl chloride solution of the same mass as β-cyclodextrin at a rate of 2 ml / min, the mass ratio of p-toluenesulfonyl chloride and acetonitrile in the p-toluenesulfonyl chloride solution is 8:1, stir at 1100 rpm for 3 hours, centrifuge and let stand for 18 hours, filter and recrystallize with deionized water, transfer to thiourea solution of 1.3 times the mass of β-cyclodextrin, the mass ratio of thiourea, methanol and deionized water in the thiourea solution is 1.5:4:1.5, heat to 86 ° C, reflux for 48 hours, rotary evaporate and wash with anhydrous methanol 4 times, then use The product was dissolved in 11% sodium hydroxide solution, heated to 50°C, reacted for 5.5 hours, adjusted to pH 2 with hydrochloric acid, and then added with trichloroethylene (0.03 times the mass of β-cyclodextrin), reacted at room temperature for 24 hours, filtered and dried to obtain thiol cyclodextrin. Amino polystyrene microspheres, thiol cyclodextrin and deionized water were mixed in a mass ratio of 1.25:1:40, stirred evenly, heated to 65°C, and 0.07 times the mass of amino polystyrene microspheres of thiophosgene were added, reacted for 4 hours, filtered and washed with deionized water 4 times, and dried to obtain polymer microspheres. S3. Mix water-based hydroxy acrylic acid and dispersant, stir evenly and heat to 75°C, add polymer microspheres, filler and rust inhibitor, stir at 550rpm for 40 minutes, cool to room temperature, add polyester curing agent, defoaming agent, leveling agent and deionized water, and continue stirring for 40 minutes. The mass ratio of water-based hydroxy acrylic acid, polyester curing agent, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water is 55:1.5:6:3:1:1:1.5:1:1.5:15 to prepare polyester curing agent and polyester curing agent modified water-based acrylic anti-corrosion coating.

[0024] Example 3 The preparation method of the water-based acrylic anticorrosive coating modified with a polyester curing agent in this embodiment is as follows: S1. Under a nitrogen atmosphere, epoxy cyclohexane, oxalic acid and catalyst tetrabutyl titanate were mixed in a molar ratio of 2.2:1:0.04, heated to 75 ° C, and kept warm for 3 hours to obtain epoxy cyclohexane adipate; under a nitrogen atmosphere, maleic anhydride, butanone and n-butane were mixed in a mass ratio of 1.2:4:6, stirred evenly, and then 3.3 times the mass of maleic anhydride trimethylolpropane trimethacrylate and 0.008 times the mass of maleic anhydride were added. Azoisobutyronitrile was heated to 72°C, reacted for 8 hours, filtered and extracted with acetone Soxhlet for 48 hours to obtain polymaleic anhydride resin; under a nitrogen atmosphere, polymaleic anhydride resin and acetone were mixed in a mass ratio of 1:8, and after sufficient swelling, 1.5 times the mass of polymaleic anhydride resin epoxycyclohexane and 0.04 times the mass of polymaleic anhydride resin catalyst triethylamine were added, the temperature was raised to 150°C, reacted for 6 hours, and vacuum rotary evaporation was performed to obtain a polyester curing agent; S2. The stabilizer polyvinyl pyrrolidone, ethanol and deionized water were mixed in a mass ratio of 1:10:50, stirred evenly, and then 0.04 times the mass of polyvinyl pyrrolidone and 4 times the mass of polystyrene were added. The temperature was raised to 72 ° C, nitrogen was passed through at a rate of 5m / s for 14h, centrifuged and washed 5 times with anhydrous ethanol, and finally evaporated to dryness to obtain polystyrene microspheres; polystyrene microspheres and deionized water were mixed in a mass ratio of 1:12, stirred evenly, and polystyrene microspheres were added under stirring at 1200rpm. The mixture was stirred for 2 h in a 2 mol / L sodium hydroxide solution 30 times the mass of the polystyrene microspheres, and the mixture was heated to 78 ° C. Then, 0.3 times the mass of the polystyrene microspheres was added with sodium dithionite as a reducing agent, and the mixture was stirred for 4 h. The mixture was filtered and washed with deionized water 5 times, and the mixture was dried to obtain amino polystyrene microspheres. β-cyclodextrin, sodium hydroxide and deionized water were mixed in a mass ratio of 1:0.1:12 and stirred evenly. After homogenization, add p-toluenesulfonyl chloride solution of the same mass as β-cyclodextrin at a rate of 1-3 ml / min, the mass ratio of p-toluenesulfonyl chloride and acetonitrile in the p-toluenesulfonyl chloride solution is 8:1.2, stir at 1200 rpm for 4 h, centrifuge and let stand for 24 h, filter and recrystallize with deionized water, transfer to thiourea solution of 1.4 times the mass of β-cyclodextrin, the mass ratio of thiourea, methanol and deionized water in the thiourea solution is 1.5:4:2, heat to 88 ° C, reflux for 48 h, rotary evaporate and wash with anhydrous methanol 5 times, then use The product was dissolved in 12% sodium hydroxide solution, heated to 55°C, reacted for 6 hours, adjusted to pH 2.2 with hydrochloric acid, and then added with trichloroethylene (0.04 times the mass of β-cyclodextrin), reacted at room temperature for 24 hours, filtered and dried to obtain thiol cyclodextrin. Amino polystyrene microspheres, thiol cyclodextrin and deionized water were mixed in a mass ratio of 1.3:1:50, stirred evenly, heated to 70°C, and 0.08 times the mass of amino polystyrene microspheres of thiophosgene were added, reacted for 5 hours, filtered and washed with deionized water 5 times, and dried to obtain polymer microspheres. S3. Mix water-based hydroxy acrylic acid and dispersant, stir evenly and heat to 80°C, add polymer microspheres, filler and rust inhibitor, stir at 600 rpm for 50 minutes, cool to room temperature, add polyester curing agent, defoaming agent, leveling agent and deionized water, and continue stirring for 50 minutes. The mass ratio of water-based hydroxy acrylic acid, polyester curing agent, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water is 60:2:8:4:1.5:1.5:2:1.5:2:20 to obtain polyester curing agent and polyester curing agent modified water-based acrylic anti-corrosion coating.

[0025] Comparative Example 1 The preparation method of Comparative Example 1 is the same as that of Example 2. The difference between the polyester curing agent modified waterborne acrylic anticorrosive coating and Example 2 is that the polyester curing agent is only polymaleic anhydride resin.

[0026] Comparative Example 2 The preparation method of Comparative Example 2 is the same as that of Example 2. The difference between the polyester curing agent-modified water-based acrylic anti-corrosion coating and Example 2 is that the components of the polyester curing agent and the polyester curing agent-modified water-based acrylic anti-corrosion coating are only water-based hydroxy acrylic acid, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water.

[0027] Comparative Example 3 The preparation method of Comparative Example 3 is the same as that of Example 2. The difference between the polyester curing agent modified water-based acrylic anticorrosive coating and Example 2 is that the polymer microspheres are only amino polystyrene microspheres.

[0028] Comparative Example 4 The preparation method of Comparative Example 4 is the same as that of Example 2. The difference between the polyester curing agent-modified water-based acrylic anti-corrosion coating and Example 2 is that the components of the polyester curing agent and the polyester curing agent-modified water-based acrylic anti-corrosion coating are only water-based hydroxy acrylic acid, polyester curing agent, amino polystyrene microspheres, mercapto cyclodextrin, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water.

[0029] Comparative Example 5 The preparation method of Comparative Example 5 is the same as that of Example 2. The difference between the polyester curing agent-modified water-based acrylic anti-corrosion coating and Example 2 is that the components of the polyester curing agent and the polyester curing agent-modified water-based acrylic anti-corrosion coating are only water-based hydroxy acrylic acid, polyester curing agent, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water.

[0030] Effect Examples Table 1 below shows the performance test results of the polyester curing agent-modified waterborne acrylic anticorrosive coatings prepared in Examples and Comparative Examples; Table 1 hardness Alkali resistance Alkali resistance Example 1 2H ＞800h No bubbles or shedding Example 2 2H ＞800h No bubbles or shedding Example 3 2H ＞800h No bubbles or shedding Comparative Example 1 H ＞800h No bubbles or shedding Comparative Example 2 H ＞800h No bubbles or shedding Comparative Example 3 2H ＜800h No bubbles, no shedding, slight discoloration Comparative Example 4 2H ＜800h No bubbles, no shedding, slight discoloration Comparative Example 5 H ＜800h No bubbles, no shedding, slight discoloration From the comparison of the performance data in Table 1, it can be seen that the polyester curing agent and the water-based acrylic anti-corrosion coating modified with the polyester curing agent prepared in the present invention have excellent mechanical properties and anti-corrosion properties; From the comparison of the experimental data of Example 1, Example 2, Example 3 and Comparative Example 1, Comparative Example 2, it can be found that maleic anhydride and trimethylolpropane trimethacrylate react to form a three-dimensional network structure of polymaleic anhydride resin, which then reacts with epoxy cyclohexane adipate to form a polyester curing agent with cross-linking properties. The polyester curing agent is introduced into the water-based hydroxy acrylic acid to form a dense cross-linked network, so that the coating has a high density after coating and film formation, thereby enhancing the mechanical properties of the coating.

[0031] From the comparison of the experimental data of Example 1, Example 2, Example 3 and Comparative Example 3, Comparative Example 4, Comparative Example 5, it can be found that the introduction of amino polystyrene microspheres with excellent mechanical properties and the reaction with mercaptocyclodextrin to form thiourea in the coating not only enhances the interaction between the polymer microspheres and the water-based hydroxy acrylic resin, but also improves the chemical corrosion resistance of the coating. The cavity structure of mercaptocyclodextrin can adsorb and fix some small molecule corrosive media, further enhancing the anti-corrosion effect of the coating. The introduction of polymer microspheres enables the coating to form a more complex and dense microstructure during the film formation process. This structure is conducive to enhancing the mechanical strength and anti-permeability of the coating, thereby comprehensively improving the anti-corrosion performance of the coating.

[0032] Obviously, the above embodiments are merely examples for the purpose of clearly illustrating the embodiments of the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will readily appreciate that other variations or modifications based on the above description are possible. It is not necessary and impossible to enumerate all embodiments here. However, such obvious variations or modifications arising from the spirit of the present invention remain within the scope of protection of the present invention.

Claims

1. A polyester curing agent, characterized in that The polyester curing agent is prepared by the reaction of polymaleic anhydride resin and epoxy cyclohexane adipate; the polymaleic anhydride resin is prepared by the reaction of maleic anhydride and trimethylolpropane trimethacrylate; and the epoxy cyclohexane adipate is prepared by the reaction of epoxy cyclohexane and oxalic acid.

2. A polyester curing agent modified water-based acrylic anti-corrosion coating, comprising the polyester curing agent according to claim 1, characterized in that: It also includes water-based hydroxy acrylic acid, polymer microspheres, fillers, dispersants, film formers, defoamers, leveling agents, rust inhibitors and deionized water.

3. The polyester curing agent modified water-based acrylic anti-corrosion coating according to claim 2, characterized in that: The polymer microspheres are prepared by reacting amino polystyrene microspheres with mercapto cyclodextrin.

4. The polyester curing agent modified water-based acrylic anti-corrosion coating according to claim 2, characterized in that: The filler is calcium carbonate; the dispersant is oxidized polyethylene wax; the film-forming agent is propylene glycol phenyl ether; the defoamer is BYK-022; the leveling agent is BYK-333; and the rust inhibitor is alkenyl succinate.

5. A method for preparing a polyester curing agent modified water-based acrylic anti-corrosion coating, for preparing the polyester curing agent modified water-based acrylic anti-corrosion coating as claimed in claim 2, characterized in that: The specific steps include: S1. Under a nitrogen atmosphere, polymaleic anhydride resin and acetone were mixed in a mass ratio of 1:6-8. After sufficient swelling, 1.3-1.5 times the mass of polymaleic anhydride resin epoxycyclohexane adipate and 0.02-0.04 times the mass of polymaleic anhydride resin catalyst triethylamine were added. The temperature was raised to 120-150°C, the reaction was carried out for 4-6 hours, and the polyester curing agent was obtained by vacuum rotary evaporation. S2. Aminopolystyrene microspheres, mercaptocyclodextrin, and deionized water were mixed in a mass ratio of 1.2-1.3:1:30-50, stirred, and heated to 60-70°C. Thiophosgene (0.06-0.08 times the mass of the aminopolystyrene microspheres) was added and reacted for 3-5 hours. The mixture was filtered, washed with deionized water 3-5 times, and dried to produce polymer microspheres. S3. Mix water-based hydroxy acrylic acid and dispersant, stir evenly and heat to 70~80℃, add polymer microspheres, filler and rust inhibitor, stir at 500~600rpm for 30~50min, cool to room temperature, add polyester curing agent, defoaming agent, leveling agent and deionized water, and continue stirring for 30~50min. The mass ratio of water-based hydroxy acrylic acid, polyester curing agent, polymer microspheres, filler, dispersant, film-forming agent, defoaming agent, leveling agent, rust inhibitor and deionized water is 50~60:1~2:4~8:2~4:0.5~1.5:0.5~1.5:1~2:0.5~1.5:1~2:10~20 to prepare polyester curing agent and polyester curing agent modified water-based acrylic anti-corrosion coating.

6. The method for preparing the polyester curing agent modified water-based acrylic anti-corrosion coating according to claim 5, characterized in that: In the above step S1, the preparation method of epoxy cyclohexane adipate is: under a nitrogen atmosphere, epoxy cyclohexane, oxalic acid and catalyst tetrabutyl titanate are mixed in a molar ratio of 2-2.2:1:0.02-0.04, the temperature is raised to 65-75°C, and the temperature is kept for reaction for 2-3 hours to obtain epoxy cyclohexane adipate.

7. The method for preparing the polyester curing agent modified water-based acrylic anticorrosive coating according to claim 5, characterized in that: In the above step S1, the preparation method of the polymaleic anhydride resin is as follows: under a nitrogen atmosphere, maleic anhydride, butanone and n-butane are mixed in a mass ratio of 0.8~1.2:4:6, stirred evenly, and then trimethylolpropane trimethacrylate (3.1~3.3 times the mass of maleic anhydride) and azoisobutyronitrile (0.006~0.008 times the mass of maleic anhydride) are added, the temperature is raised to 68~72°C, the reaction is carried out for 6~8h, the mixture is filtered and extracted with acetone Soxhlet for 48h to obtain the polymaleic anhydride resin.

8. The method for preparing the polyester curing agent modified water-based acrylic anticorrosive coating according to claim 5, characterized in that: In the above step S2, the preparation method of amino polystyrene microspheres is: polystyrene microspheres and deionized water are mixed in a mass ratio of 1:10~12, stirred evenly, and added with mixed acid 2~4 times the mass of the polystyrene microspheres under stirring at 800~1200 rpm, wherein the volume ratio of concentrated sulfuric acid to 20~30% nitric acid in the mixed acid is 3:2, reacting for 1~2h, filtering and washing with deionized water 3~5 times, transferring to 20~30 times the mass of polystyrene microspheres. 2mol / L sodium hydroxide solution, heating to 76~78°C, and then adding 0.1~0.3 times the mass of the polystyrene microspheres. Sodium dithionite, a reducing agent, reacting for 3~4h, filtering and washing with deionized water 3~5 times, and drying to obtain amino polystyrene microspheres.

9. The method for preparing the polyester curing agent modified water-based acrylic anticorrosive coating according to claim 8, characterized in that: The preparation method of the polystyrene microspheres comprises the following steps: mixing a stabilizer polyvinyl pyrrolidone, ethanol and deionized water in a mass ratio of 1:8-10:50, stirring evenly, adding 0.02-0.04 times the mass of polyvinyl pyrrolidone of azobisisobutyronitrile and 2-4 times the mass of polyvinyl pyrrolidone of polystyrene, heating to 68-72° C., passing nitrogen gas at a rate of 1-5 m / s for reaction for 12-14 hours, centrifuging and washing with anhydrous ethanol for 3-5 times, and finally evaporating to dryness to obtain the polystyrene microspheres.

10. The method for preparing the polyester curing agent modified water-based acrylic anti-corrosion coating according to claim 5, characterized in that: In the above step S2, the preparation method of mercaptocyclodextrin is as follows: β-cyclodextrin, sodium hydroxide and deionized water are mixed in a mass ratio of 1:0.1:10~12, stirred evenly, and a p-toluenesulfonyl chloride solution of equal mass of β-cyclodextrin is added dropwise at a rate of 1~3 ml / min, wherein the mass ratio of p-toluenesulfonyl chloride and acetonitrile in the p-toluenesulfonyl chloride solution is 8:0.8~1.2, stirred at 1000~1200 rpm for 2~4 hours, centrifuged and allowed to stand for 12~24 hours, filtered and recrystallized with deionized water, and transferred to the β-cyclodextrin mass The product was prepared by adding 1.2-1.4 times the amount of thiourea solution, wherein the mass ratio of thiourea, methanol and deionized water in the thiourea solution was 1.5:4:1-2, heating to 85-88°C, reflux reaction for 48 hours, rotary evaporation and washing with anhydrous methanol for 3-5 times, dissolving with 10-12% sodium hydroxide solution, heating to 45-55°C, reacting for 5-6 hours, adjusting the pH to 1.8-2.2 with hydrochloric acid, adding trichloroethylene in an amount of 0.02-0.04 times the mass of β-cyclodextrin, reacting at room temperature for 24 hours, filtering and drying to obtain mercaptocyclodextrin.