Weather-resistant water-based two-component epoxy paint and preparation method thereof

Abstract

The invention discloses weather-resistant water-based two-component epoxy paint and a preparation method thereof, and belongs to the technical field of paint. The weather-resistant water-based two-component epoxy paint comprises a component A and a component B, the component A comprises 50-70 parts by mass of a modified waterborne epoxy emulsion, 3-6 parts by mass of a pigment, 7-13 parts by mass of a modified filler, 0.3-1.5 parts by mass of a wetting dispersant, 2-4 parts by mass of a coalescing agent, 0.1-0.5 part by mass of a defoaming agent, 0.5-5 parts by mass of water and 0.5-1 part by mass of a leveling agent; the component B comprises 35-65 parts by mass of a modified curing agent, 10-20 parts by mass of ethanol and 30-40 parts by mass of water; the component A and the component B are mixed according to the mass ratio of 100: (20-30); the modified curing agent is obtained by reacting polyethylene glycol diglycidyl ether, epoxy resin, triethylene tetramine, functional organic silicon and phenyl glycidyl ether; the modified filler is obtained by modifying nano silicon dioxide with poly (m-xylylenediamine) and a silane coupling agent KH560; the modified water-based epoxy emulsion is a phytic acid modified water-based epoxy emulsion.

Description

Technical Field

[0001] The invention relates to a weather-resistant water-based two-component epoxy paint and a preparation method thereof. Background Art

[0002] With the increasing awareness of environmental protection and increasingly stringent legal and regulatory requirements, waterborne coatings have attracted widespread attention due to their low VOC (volatile organic compound) emission characteristics. As an important waterborne coating substrate, waterborne epoxy resin has broad application prospects in the fields of metal corrosion protection. However, the performance of waterborne epoxy resin is directly affected by the type of its curing agent. The choice of curing agent is not only related to the film-forming quality of the coating, but also determines the physical and chemical properties of the final coating.

[0003] Waterborne epoxy resin curing agents mainly include polyamide curing agents, anhydride curing agents, epoxy-polyamine curing agents, etc. These curing agents have their own characteristics, but in terms of comprehensive performance, epoxy-polyamine curing agents have become one of the most commonly used curing agents due to their high flexibility in molecular design and wide range of applications. However, although epoxy-polyamine curing agents are excellent in improving the mechanical strength and flexibility of waterborne epoxy resins, they also have some obvious shortcomings, especially the high water absorption rate of the cured coating, which directly leads to a decrease in the corrosion resistance of the coating and limits its application in certain special environments.

[0004] In order to overcome the above problems, researchers began to explore the method of modifying epoxy-polyamine curing agents by introducing other functional substances in order to obtain more ideal coating performance. Among them, silicone materials have become an ideal choice for modifying waterborne epoxy resins due to their unique low surface energy, excellent weather resistance and heat resistance. By introducing silicone molecular structures into epoxy-polyamine curing agents, not only can the hydrophobicity and water resistance of the cured coating be significantly improved, but also its toughness and corrosion resistance can be enhanced, thereby meeting a wider range of application needs.

[0005] Therefore, the present invention provides a weather-resistant water-based two-component epoxy paint and a preparation method thereof. Summary of the invention

[0006] The purpose of the present invention is to provide a weather-resistant water-based two-component epoxy paint and a preparation method thereof, so as to solve the technical problems mentioned in the above background technology.

[0007] The technical solution for achieving the purpose of the present invention is:

[0008] A weather-resistant water-based two-component epoxy paint comprises a component A and a component B. In terms of weight, the raw material components of the component A comprise 50 to 70 parts by weight of a modified water-based epoxy emulsion, 3 to 6 parts by weight of a pigment, 7 to 13 parts by weight of a modified filler, 0.3 to 1.5 parts by weight of a wetting dispersant, 2 to 4 parts by weight of a film-forming aid, 0.1 to 0.5 parts by weight of a defoamer, 0.5 to 5 parts by weight of water, and 0.5 to 1 parts by weight of a leveling agent; the raw material components of the component B comprise 35 to 65 parts by weight of a modified curing agent, 10 to 20 parts by weight of ethanol, and 30 to 40 parts by weight of water.

[0009] Furthermore, component A and component B are mixed in a mass ratio of 100:20-30.

[0010] Furthermore, the modified waterborne epoxy emulsion is a waterborne epoxy emulsion modified by phytic acid.

[0011] Furthermore, the modified filler is obtained by modifying nano-silica with poly-m-phenylenediamine and silane coupling agent KH560.

[0012] Furthermore, the modified curing agent is obtained by reacting polyethylene glycol diglycidyl ether, epoxy resin, triethylenetetramine, functionalized silicone, and phenyl glycidyl ether, wherein the functionalized silicone is obtained by modifying hydrogenated silicone oil with allyl polyethylene glycol and allyl glycidyl ether.

[0013] A method for preparing a weather-resistant water-based two-component epoxy paint comprises the following preparation steps:

[0014] (1) Weigh the above raw material components according to their weight parts;

[0015] (2) putting the water, wetting dispersant and defoaming agent weighed in step (1) into a container, stirring at 80-120 r / min until the wetting dispersant is dissolved; then adding pigment and modified filler under stirring at 80-120 r / min, then dispersing at 1000-2000 r / min for 28-32 min, then adjusting the stirring speed to 80-120 r / min, adding modified waterborne epoxy emulsion, film-forming aid and leveling agent in sequence while stirring, and then stirring and dispersing at 300-500 r / min for 10-20 min to obtain component A, which is stored for later use;

[0016] (3) placing the modified curing agent, ethanol and water weighed in step (1) into a container, and stirring and dispersing at 800 to 1200 r / min for 15 to 25 minutes;

[0017] (4) Component A and component B are mixed at a mass ratio of 100:20-30 at 400-800 r / min for 20-40 min, left for 30 min, and then coated on the surface of the substrate using a roller coater. The coating is further cured at 100-110° C. for 25-35 min to obtain a weather-resistant water-based two-component epoxy paint with a thickness of 49.5-50.5 μm.

[0018] Furthermore, the preparation steps of the modified waterborne epoxy emulsion are as follows: 5 to 7 parts by mass of emulsifier and 4.2 to 4.4 parts by mass of phytic acid are stirred at 80 to 120 r / min for 29 to 31 minutes, and then 18 to 22 parts by mass of epoxy resin and 2.3 to 2.5 parts by mass of ethylene glycol propyl ether are added, melted at 79 to 81° C. and stirred evenly, and then the temperature is reduced to 39 to 41° C., and 18 to 20 parts by mass of deionized water are added dropwise at 1000 to 2000 r / min while stirring to obtain a modified waterborne epoxy emulsion.

[0019] Furthermore, the preparation steps of the modified curing agent are as follows: polyethylene glycol diglycidyl ether is heated to 64-66° C., and then triethylenetetramine is added dropwise, and the addition is completed within 30 minutes, and the mixture is stirred at a stirring speed of 200-300 r / min and kept warm for 3.8-4.2 hours, and then the excess triethylenetetramine is removed by rotary evaporation, and then a propylene glycol methyl ether solution of epoxy resin with a concentration of 48-52% is added dropwise, and the addition is completed within 30 minutes, and the reaction is kept warm for 2.8-3.2 hours, and then the functionalized The organosilicon is used as a capping agent to react for 28 to 32 minutes, and finally phenyl glycidyl ether is added, and the reaction is continued for 55 to 65 minutes. Deionized water is added to adjust the solid content of the system to 40 to 60%, and stirring is continued for 55 to 65 minutes to obtain a modified curing agent; wherein the molar ratio of polyethylene glycol diglycidyl ether, triethylenetetramine, epoxy group of epoxy resin, functionalized organosilicon, and phenyl glycidyl ether is 1:2 to 3:0.55 to 0.65:0.14 to 0.18:0.56 to 0.72.

[0020] Furthermore, the preparation steps of the functionalized silicone are as follows: a toluene solution of 10% allyl polyethylene glycol and a 25 μg / g chloroplatinic acid-isopropanol catalyst are mixed in a mass ratio of 1:0.05, and the temperature is raised to 74-76°C for dehydration for 28-32 minutes; then hydrogenated silicone oil is added dropwise within 28-32 minutes, the temperature is raised to 130-140°C, and after reacting for 2.5-3.5 hours, the reaction temperature is lowered to 84-86°C, and allyl glycidyl ether is added, and the reaction is continued for 3.5-4.5 hours, and then the toluene solvent is removed by rotary evaporation to obtain functionalized silicone; wherein the molar ratio of allyl polyethylene glycol, silicon-hydrogen bonds in hydrogenated silicone oil, and allyl glycidyl ether is 0.7-0.8:1:0.2-0.3.

[0021] Furthermore, the preparation steps of the modified filler are as follows: 2.5-2.7 parts by mass of tetraethyl orthosilicate, 47-49 parts by mass of anhydrous ethanol and 19-21 parts by mass of deionized water, preheating at 79-81° C. for 28-32 minutes under stirring at 400-600 r / min, adjusting the pH to 7.5-8.5 with ammonium hydroxide, reacting at 48-52° C. for 11-13 hours, adding 0.56-0.58 parts by mass of silane coupling agent KH560, continuing stirring at 54-56° C. for 5.5-6.5 hours, washing with deionized water and anhydrous ethanol, centrifuging 4-6 times, and vacuum drying at 100° C. for 12 hours to obtain nano-silica modified with silane coupling agent KH560;

[0022] 0.4-0.6 parts by weight of m-phenylenediamine is added to 48-52 parts by weight of 0.6 mol / L ammonia water and ultrasonically treated for 28-32 minutes to obtain a m-phenylenediamine dispersion; 1.57-1.59 parts by weight of ammonium persulfate and 20 parts by weight of deionized water are mixed and stirred for 18-22 minutes, and the addition is completed within 30 minutes to obtain an initiator solution; under stirring in an ice water bath, the initiator solution is added dropwise to the m-phenylenediamine dispersion within 30 minutes, reacted at 29-31° C. for 5.5-6.5 hours, then centrifuged and repeatedly washed with deionized water and anhydrous ethanol to remove unreacted oligomers, and dried at 70° C. for 8 hours to obtain poly-m-phenylenediamine;

[0023] 0.15-0.25 parts by weight of silane coupling agent KH560 modified nano-silica is dissolved in 50 parts by weight of acetone, and ultrasonically treated for 28-32 minutes to form a uniform silane coupling agent KH560 modified nano-silica dispersion; 0.2-0.3 parts by weight of poly-m-phenylenediamine is weighed and dispersed in 18-22 parts by weight of acetone, and then added to the silane coupling agent KH560 modified nano-silica dispersion, and reacted at 78-82° C. with magnetic stirring for 9.5-10.5 hours, and repeatedly washed with deionized water and centrifuged for 4-6 times, and dried to obtain a modified filler.

[0024] By adopting the above technical solution, the present invention has the following beneficial effects:

[0025] The invention discloses a weather-resistant water-based two-component epoxy paint and a preparation method thereof, and belongs to the technical field of coatings. The weather-resistant water-based two-component epoxy paint comprises a component A and a component B. The component A comprises a modified water-based epoxy emulsion, a pigment, a modified filler, a wetting dispersant, a film-forming aid, a defoamer, water and a leveling agent. The component B comprises a modified curing agent, ethanol and water. The modified curing agent is obtained by reacting polyethylene glycol diglycidyl ether, epoxy resin, triethylenetetramine, functionalized organic silicon and phenyl glycidyl ether. The modified filler is obtained by modifying nano silicon dioxide with poly-m-phenylenediamine and a silane coupling agent KH560. The modified water-based epoxy emulsion is a water-based epoxy emulsion modified by phytic acid.

[0026] Firstly, the present invention uses triethylenetetramine as a raw material and introduces hydrophilic polyethylene glycol diglycidyl ether and epoxy resin chain segments, so as to effectively improve the compatibility between a modified curing agent and a modified waterborne epoxy emulsion. Furthermore, functionalized organic silicon obtained by introducing allyl polyethylene glycol and allyl glycidyl ether modified hydrogen-containing silicone oil improves the hydrophobicity, water resistance, toughness and corrosion resistance of the epoxy resin by utilizing the low surface energy, strong weather resistance, high heat resistance and stable and flexible Si-O-Si structure of organic silicon. Allyl polyethylene glycol and allyl glycidyl ether modified hydrogen-containing silicone oil can effectively increase the compatibility between the functionalized organic silicon and the modified waterborne epoxy emulsion.

[0027] Secondly, the present invention introduces poly(meta-phenylenediamine) and silane coupling agent KH560 to modify nano-silica in the weather-resistant water-based two-component epoxy paint. The nano-silica exhibits strong light reflection performance, and the average reflectivity in the ultraviolet band reaches about 83%. The reflectivity of ultraviolet light with a wavelength of 270 to 400 nm is above 90%, which can effectively enhance the ultraviolet weather resistance of the weather-resistant water-based two-component epoxy paint. However, the high surface energy of silicon dioxide makes it easy to agglomerate and settle in the coating. The use of poly(meta-phenylenediamine) and silane coupling agent KH560 can effectively improve this problem and increase the compatibility between nano-silica and the modified water-based epoxy emulsion.

[0028] Next, phytic acid is an organophosphorus compound that can be extracted from the seeds, roots and stems of plants. Its molecule contains 6 phosphate groups, has excellent water solubility and strong chelating ability. The use of phytic acid-modified water-based epoxy emulsion can produce a tight metal protective layer on the surface of the metal substrate through chelation, effectively enhancing the corrosion resistance of the metal surface and the adhesion between the metal substrate and the epoxy resin.

[0029] Finally, component A includes modified water-based epoxy emulsion, pigment, modified filler, wetting dispersant, film-forming aid, defoamer, water, and leveling agent; component B includes modified curing agent, ethanol, and water; component A and component B are mixed, and part of the amino group in the poly(m-phenylenediamine) part is successfully converted into ammonium salt, which is combined with phytic acid through electrostatic attraction and hydrogen bonding to uniformly disperse nano-silica in the modified water-based epoxy emulsion. At the same time, the poly(m-phenylenediamine) and phytic acid work synergistically to enhance the corrosion resistance of the weather-resistant water-based two-component epoxy paint. DETAILED DESCRIPTION

[0030] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with specific implementation methods.

[0031] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention.

[0032] Some of the raw material components of the embodiments of the present invention and the comparative examples are as follows:

[0033] The film-forming aid is propylene glycol methyl ether;

[0034] The pigment is red iron oxide;

[0035] The wetting and dispersing agent was Nuosperse FA 182 from Shengwo, the Netherlands;

[0036] The leveling agent is Tego Glide440 from Germany;

[0037] The defoamer was obtained from Serdas7015 of Shengwo, the Netherlands;

[0038] The emulsifier is sodium dodecylbenzene sulfonate;

[0039] The epoxy resin adopts epoxy resin E44;

[0040] The hydrogen content of hydrogen-containing silicone oil is 1.0.

[0041] (Example 1)

[0042] A method for preparing a weather-resistant water-based two-component epoxy paint comprises the following preparation steps:

[0043] (1) Weigh the following raw material components according to their weight parts: 50 parts by weight of modified waterborne epoxy emulsion, 3 parts by weight of pigment, 7 parts by weight of modified filler, 0.3 parts by weight of wetting and dispersing agent, 2 parts by weight of film-forming aid, 0.1 parts by weight of defoaming agent, 0.5 parts by weight of water, and 0.5 parts by weight of leveling agent; the raw material components of component B include 35 parts by weight of modified curing agent, 10 parts by weight of ethanol, and 30 parts by weight of water;

[0044] (2) putting the water, wetting dispersant and defoaming agent weighed in step (1) into a container, stirring at 80 r / min until the wetting dispersant is dissolved; then adding pigment and modified filler under stirring at 80 r / min, then dispersing at 1000 r / min for 28 min, then adjusting the stirring speed to 80 r / min, adding modified waterborne epoxy emulsion, film-forming aid and leveling agent in sequence while stirring, and then stirring and dispersing at 300 r / min for 10 min to obtain component A, which is stored for later use;

[0045] (3) putting the modified curing agent, ethanol and water weighed in step (1) into a container and stirring and dispersing at 800 r / min for 15 min;

[0046] (4) Component A and component B were mixed at a mass ratio of 100:20 at 400 r / min for 20 min, left to stand for 30 min, and then coated on the surface of the substrate using a roller coater. The coating was further cured at 100° C. for 25 min to obtain a weather-resistant water-based two-component epoxy paint with a thickness of 49.5 μm.

[0047] The preparation steps of the modified waterborne epoxy emulsion are as follows: 5 parts by mass of emulsifier and 4.2 parts by mass of phytic acid are stirred at 80 r / min for 29 minutes, then 18 parts by mass of epoxy resin and 2.3 parts by mass of ethylene glycol propyl ether are added, melted at 79° C. and stirred evenly, then the temperature is reduced to 39° C., and 18 parts by mass of deionized water are added dropwise at 1000 r / min while stirring to obtain the modified waterborne epoxy emulsion.

[0048] The preparation steps of the modified curing agent are as follows: heating polyethylene glycol diglycidyl ether to 64° C., then dripping triethylenetetramine, the dripping is completed within 30 minutes, stirring at a stirring speed of 200 r / min and keeping the temperature for reaction for 3.8 hours, then rotary evaporation to remove excess triethylenetetramine, then dripping a propylene glycol methyl ether solution of epoxy resin with a concentration of 48%, the dripping is completed within 30 minutes, and the heat preservation reaction is continued for 2.8 hours, then functionalized silicone is added as a capping agent for reaction for 28 minutes, and finally phenyl glycidyl ether is added, the reaction is continued for 55 minutes, deionized water is added, the solid content of the system is adjusted to 40%, and stirring is continued for 55 minutes to obtain the modified curing agent; wherein the molar ratio of polyethylene glycol diglycidyl ether, triethylenetetramine, epoxy group of epoxy resin, functionalized silicone, and phenyl glycidyl ether is 1:2:0.55:0.14:0.56.

[0049] The preparation steps of the functionalized silicone are as follows: a toluene solution of allyl polyethylene glycol with a concentration of 10% and a chloroplatinic acid-isopropanol catalyst of 25 μg / g are mixed in a mass ratio of 1:0.05, and the mixture is heated to 74°C for dehydration for 28 minutes; then, hydrogenated silicone oil is added dropwise within 28 minutes, the mixture is heated to 130°C, the reaction temperature is lowered to 84°C, allyl glycidyl ether is added, the reaction is continued for 3.5 hours, and the toluene solvent is removed by rotary evaporation to obtain the functionalized silicone; wherein the molar ratio of allyl polyethylene glycol, silicon-hydrogen bonds in hydrogenated silicone oil, and allyl glycidyl ether is 0.7:1:0.3.

[0050] The preparation steps of the modified filler are as follows: 2.5 parts by mass of tetraethyl orthosilicate, 47 parts by mass of anhydrous ethanol and 19 parts by mass of deionized water are preheated at 79° C. for 28 minutes under stirring at 400 r / min, the pH is adjusted to 7.5 with ammonium hydroxide, and the mixture is reacted at 48° C. for 11 hours, 0.56 parts by mass of silane coupling agent KH560 is added, stirring is continued at 54° C. for 5.5 hours, the mixture is washed with deionized water and anhydrous ethanol and centrifuged for 4 times, and vacuum dried at 100° C. for 12 hours to obtain nano-silica modified with silane coupling agent KH560;

[0051] 0.4 parts by mass of m-phenylenediamine was added to 48 parts by mass of 0.6 mol / L ammonia water and ultrasonically treated for 28 minutes to obtain a m-phenylenediamine dispersion; 1.57 parts by mass of ammonium persulfate was mixed with 20 parts by mass of deionized water and stirred for 18 minutes, and the mixture was added dropwise within 30 minutes to obtain an initiator solution; the initiator solution was added dropwise to the m-phenylenediamine dispersion under stirring in an ice water bath, and the addition was completed within 30 minutes, and the mixture was reacted at 29° C. for 5.5 hours, and then centrifuged and repeatedly washed with deionized water and anhydrous ethanol to remove unreacted oligomers, and dried at 70° C. for 8 hours to obtain poly-m-phenylenediamine;

[0052] 0.15 parts by mass of silane coupling agent KH560 modified nano-silica was dissolved in 50 parts by mass of acetone, and ultrasonically treated for 28 minutes to form a uniform silane coupling agent KH560 modified nano-silica dispersion; 0.2 parts by mass of poly(m-phenylenediamine) was weighed and dispersed in 18 parts by mass of acetone, and then added to the silane coupling agent KH560 modified nano-silica dispersion, and reacted with magnetic stirring at 78°C for 9.5 hours, and repeatedly washed with deionized water and centrifuged 4 times, and dried to obtain a modified filler.

[0053] (Example 2)

[0054] A method for preparing a weather-resistant water-based two-component epoxy paint comprises the following preparation steps:

[0055] (1) Weigh the following raw material components according to their weight parts: 60 parts by weight of modified waterborne epoxy emulsion, 4.5 parts by weight of pigment, 10 parts by weight of modified filler, 0.9 parts by weight of wetting and dispersing agent, 3 parts by weight of film-forming aid, 0.8 parts by weight of defoaming agent, 2.8 parts by weight of water, and 0.8 parts by weight of leveling agent; the raw material components of component B include 50 parts by weight of modified curing agent, 15 parts by weight of ethanol, and 35 parts by weight of water;

[0056] (2) putting the water, wetting dispersant and defoaming agent weighed in step (1) into a container, stirring at 100 r / min until the wetting dispersant is dissolved; then adding pigment and modified filler under stirring at 100 r / min, then dispersing at 1500 r / min for 30 min, then adjusting the stirring speed to 100 r / min, adding modified waterborne epoxy emulsion, film-forming aid and leveling agent in sequence while stirring, and then stirring and dispersing at 400 r / min for 15 min to obtain component A, which is stored for later use;

[0057] (3) putting the modified curing agent, ethanol and water weighed in step (1) into a container and stirring and dispersing at 1000 r / min for 20 min;

[0058] (4) Component A and component B were mixed at a mass ratio of 100:25 at 600 r / min for 30 min, left to stand for 30 min, and then coated on the surface of the substrate using a roller coater. The coating was further cured at 105° C. for 30 min to obtain a weather-resistant water-based two-component epoxy paint with a thickness of 50 μm.

[0059] The preparation steps of the modified waterborne epoxy emulsion are as follows: 6 parts by mass of emulsifier and 4.3 parts by mass of phytic acid are stirred at 100 r / min for 30 minutes, then 20 parts by mass of epoxy resin and 2.4 parts by mass of ethylene glycol propyl ether are added, melted at 80° C. and stirred evenly, then the temperature is reduced to 40° C., and 19 parts by mass of deionized water are added dropwise at 1500 r / min while stirring to obtain the modified waterborne epoxy emulsion.

[0060] The preparation steps of the modified curing agent are as follows: heating polyethylene glycol diglycidyl ether to 65° C., then dripping triethylenetetramine, the dripping is completed within 30 minutes, stirring at a stirring speed of 250 r / min and keeping the temperature for reaction for 4 hours, then rotary evaporation to remove excess triethylenetetramine, then dripping a propylene glycol methyl ether solution of epoxy resin with a concentration of 50%, the dripping is completed within 30 minutes, and the heat preservation reaction is continued for 3 hours, then functionalized silicone is added as a capping agent for reaction for 30 minutes, and finally phenyl glycidyl ether is added, the reaction is continued for 60 minutes, deionized water is added, the solid content of the system is adjusted to 50%, and stirring is continued for 60 minutes to obtain the modified curing agent; wherein the molar ratio of polyethylene glycol diglycidyl ether, triethylenetetramine, epoxy group of epoxy resin, functionalized silicone, and phenyl glycidyl ether is 1:2.5:0.6:0.16:0.66.

[0061] The preparation steps of the functionalized silicone are as follows: a toluene solution of allyl polyethylene glycol with a concentration of 10% and a chloroplatinic acid-isopropanol catalyst of 25 μg / g are mixed in a mass ratio of 1:0.05, and the mixture is heated to 75° C. for dehydration for 30 minutes; then, hydrogenated silicone oil is added dropwise within 30 minutes, the mixture is heated to 135° C., the reaction temperature is lowered to 85° C. after reaction for 3 hours, allyl glycidyl ether is added, the reaction is continued for 4 hours, and the toluene solvent is removed by rotary evaporation to obtain the functionalized silicone; wherein the molar ratio of allyl polyethylene glycol, silicon-hydrogen bonds in hydrogenated silicone oil, and allyl glycidyl ether is 0.75:1:0.25.

[0062] The preparation steps of the modified filler are as follows: 2.6 parts by mass of tetraethyl orthosilicate, 48 parts by mass of anhydrous ethanol and 20 parts by mass of deionized water are preheated at 80° C. for 30 minutes under stirring at 500 r / min, the pH is adjusted to 8 with ammonium hydroxide, and the mixture is reacted at 50° C. for 12 hours, 0.57 parts by mass of silane coupling agent KH560 is added, stirring is continued at 55° C. for 6 hours, the mixture is washed with deionized water and anhydrous ethanol and centrifuged for 5 times, and vacuum dried at 100° C. for 12 hours to obtain nano-silica modified with silane coupling agent KH560;

[0063] 0.5 parts by mass of m-phenylenediamine was added to 50 parts by mass of 0.6 mol / L ammonia water and ultrasonically treated for 30 minutes to obtain a m-phenylenediamine dispersion; 1.58 parts by mass of ammonium persulfate was mixed with 20 parts by mass of deionized water and stirred for 20 minutes, and the initiator solution was added dropwise within 30 minutes to obtain an initiator solution; under stirring in an ice water bath, the initiator solution was added dropwise to the m-phenylenediamine dispersion within 30 minutes, reacted at 30° C. for 6 hours, then centrifuged and repeatedly washed with deionized water and anhydrous ethanol to remove unreacted oligomers, and dried at 70° C. for 8 hours to obtain poly-m-phenylenediamine;

[0064] 0.2 parts by mass of silane coupling agent KH560 modified nano-silica was dissolved in 50 parts by mass of acetone, and ultrasonically treated for 30 minutes to form a uniform silane coupling agent KH560 modified nano-silica dispersion; 0.25 parts by mass of poly(m-phenylenediamine) was weighed and dispersed in 20 parts by mass of acetone, and then added to the silane coupling agent KH560 modified nano-silica dispersion, and reacted at 80° C. with magnetic stirring for 10 hours, and repeatedly washed with deionized water and centrifuged for 5 times, and dried to obtain a modified filler.

[0065] (Example 3)

[0066] A method for preparing a weather-resistant water-based two-component epoxy paint comprises the following preparation steps:

[0067] (1) Weigh the following raw material components according to their weight parts: 70 parts by weight of modified waterborne epoxy emulsion, 6 parts by weight of pigment, 13 parts by weight of modified filler, 1.5 parts by weight of wetting and dispersing agent, 4 parts by weight of film-forming aid, 0.5 parts by weight of defoaming agent, 5 parts by weight of water, and 1 part by weight of leveling agent; the raw material components of component B include 65 parts by weight of modified curing agent, 20 parts by weight of ethanol, and 40 parts by weight of water;

[0068] (2) putting the water, wetting dispersant and defoaming agent weighed in step (1) into a container, stirring at 120 r / min until the wetting dispersant is dissolved; then adding pigment and modified filler under stirring at 120 r / min, then dispersing at 2000 r / min for 32 min, then adjusting the stirring speed to 120 r / min, adding modified waterborne epoxy emulsion, film-forming aid and leveling agent in sequence while stirring, and then stirring and dispersing at 500 r / min for 20 min to obtain component A, which is stored for later use;

[0069] (3) putting the modified curing agent, ethanol and water weighed in step (1) into a container and stirring and dispersing at 1200 r / min for 25 min;

[0070] (4) Component A and component B were mixed at a mass ratio of 100:30 at 800 r / min for 40 min, left to stand for 30 min, and then coated on the surface of the substrate using a roller coater. The coating was further cured at 110° C. for 35 min to obtain a weather-resistant water-based two-component epoxy paint with a thickness of 50.5 μm.

[0071] The preparation steps of the modified waterborne epoxy emulsion are as follows: 7 parts by mass of emulsifier and 4.4 parts by mass of phytic acid are stirred at 120 r / min for 31 minutes, then 22 parts by mass of epoxy resin and 2.5 parts by mass of ethylene glycol propyl ether are added, melted at 81° C. and stirred evenly, then the temperature is reduced to 41° C., and 20 parts by mass of deionized water are added dropwise at 2000 r / min while stirring to obtain the modified waterborne epoxy emulsion.

[0072] The preparation steps of the modified curing agent are as follows: heating polyethylene glycol diglycidyl ether to 66° C., then dripping triethylenetetramine, the dripping is completed within 30 minutes, stirring at a stirring speed of 300 r / min and keeping the temperature for reaction for 4.2 hours, then rotary evaporation to remove excess triethylenetetramine, then dripping a propylene glycol methyl ether solution of epoxy resin with a concentration of 52%, the dripping is completed within 30 minutes, and the heat preservation reaction is continued for 3.2 hours, then functionalized silicone is added as a capping agent for reaction for 32 minutes, and finally phenyl glycidyl ether is added, the reaction is continued for 65 minutes, deionized water is added, the solid content of the system is adjusted to 60%, and stirring is continued for 65 minutes to obtain the modified curing agent; wherein the molar ratio of polyethylene glycol diglycidyl ether, triethylenetetramine, epoxy group of epoxy resin, functionalized silicone, and phenyl glycidyl ether is 1:3:0.65:0.18:0.72.

[0073] The preparation steps of the functionalized silicone are as follows: a toluene solution of allyl polyethylene glycol with a concentration of 10% and a chloroplatinic acid-isopropanol catalyst of 25 μg / g are mixed in a mass ratio of 1:0.05, and the mixture is heated to 76°C for dehydration for 32 minutes; then, hydrogenated silicone oil is added dropwise within 32 minutes, the mixture is heated to 140°C, the reaction temperature is lowered to 86°C, allyl glycidyl ether is added, the reaction is continued for 4.5 hours, and the toluene solvent is removed by rotary evaporation to obtain the functionalized silicone; wherein the molar ratio of allyl polyethylene glycol, silicon-hydrogen bonds in hydrogenated silicone oil, and allyl glycidyl ether is 0.8:1:0.2.

[0074] The preparation steps of the modified filler are as follows: 2.7 parts by mass of tetraethyl orthosilicate, 49 parts by mass of anhydrous ethanol and 21 parts by mass of deionized water are preheated at 81° C. for 32 minutes under stirring at 600 r / min, the pH is adjusted to 8.5 with ammonium hydroxide, and the mixture is reacted at 52° C. for 13 hours, 0.58 parts by mass of silane coupling agent KH560 is added, stirring is continued at 56° C. for 6.5 hours, the mixture is washed with deionized water and anhydrous ethanol and centrifuged for 6 times, and vacuum dried at 100° C. for 12 hours to obtain nano-silica modified with silane coupling agent KH560;

[0075] 0.6 parts by mass of m-phenylenediamine was added to 52 parts by mass of 0.6 mol / L ammonia water and ultrasonically treated for 32 minutes to obtain a m-phenylenediamine dispersion; 1.59 parts by mass of ammonium persulfate was mixed with 20 parts by mass of deionized water and stirred for 22 minutes, and the mixture was added dropwise within 30 minutes to obtain an initiator solution; the initiator solution was added dropwise to the m-phenylenediamine dispersion under stirring in an ice-water bath, and the addition was completed within 30 minutes, and the mixture was reacted at 31° C. for 6.5 hours, and then centrifuged and repeatedly washed with deionized water and anhydrous ethanol to remove unreacted oligomers, and dried at 70° C. for 8 hours to obtain poly-m-phenylenediamine;

[0076] 0.25 parts by mass of nano-silica modified by silane coupling agent KH560 was dissolved in 50 parts by mass of acetone, and ultrasonically treated for 32 minutes to form a uniform dispersion of nano-silica modified by silane coupling agent KH560; 0.3 parts by mass of poly(m-phenylenediamine) was weighed and dispersed in 22 parts by mass of acetone, and then added to the dispersion of nano-silica modified by silane coupling agent KH560, and reacted with magnetic stirring at 82° C. for 10.5 hours, and repeatedly washed with deionized water and centrifuged for 6 times, and dried to obtain a modified filler.

[0077] (Comparative Example 1)

[0078] The difference between Comparative Example 1 and Example 2 is that Comparative Example 1 only uses water-based epoxy emulsion; the remaining steps and ingredients are the same as those of Example 2.

[0079] (Comparative Example 2)

[0080] The difference between Comparative Example 2 and Example 2 is that Comparative Example 2 only uses silane coupling agent KH560 to modify nano-silica; the remaining steps and components are the same as Example 2.

[0081] (Comparative Example 3)

[0082] The difference between Comparative Example 3 and Example 2 is that the modified curing agent in Comparative Example 3 is obtained only by reacting polyethylene glycol diglycidyl ether, epoxy resin, triethylenetetramine, and phenyl glycidyl ether; the remaining steps and components are the same as those in Example 2.

[0083] (Comparative Example 4)

[0084] The difference between Comparative Example 4 and Example 2 is that the modified curing agent is obtained only by reacting polyethylene glycol diglycidyl ether, epoxy resin, triethylenetetramine, phenyl glycidyl ether, and hydrogen-containing silicone oil; the remaining steps and components are the same as those in Example 2.

[0085] Effect example:

[0086] Flexibility: According to GB / T193 1-1993, the flexibility of the coating is measured using a flexibility tester. A standard millimeter round rod is used to wrap it at 90° to check whether the coating surface has any peeling or cracking. Flexibility indicates whether the coating on the substrate cracks and falls off after the bending test. Referring to GB / T6742-86, the test results are expressed in millimeters (mm). The order of flexibility from best to worst is 1mm, 2mm, 3mm, 4mm, 5mm, 10mm, and 15mm.

[0087] Waterproofness: The contact angle of the weather-resistant water-based two-component epoxy paint layer prepared in the embodiment and the comparative example was measured using a JC2000DM contact angle measuring instrument produced by Shanghai Zhongchen Digital Technology Equipment Co., Ltd., and 2 μL of deionized water was used each time for the test.

[0088] Weather resistance: refer to GB / T 11186.2 to test the color difference of the weather-resistant water-based two-component epoxy paint layer prepared in the examples and comparative examples after UV aging for 1000 hours.

[0089] Anti-corrosion performance: With reference to the test examples and comparative examples of GB / T1771, an "X" was scratched on the surface of the prepared coating until the bottom plate was exposed. The coating was placed in a 35°C salt spray corrosion box, and the corrosion condition of the scratch was observed after 240 hours. The maximum corrosion width of the left and right scratches was measured.

[0090] Adhesion: The adhesion of the weather-resistant water-based two-component epoxy paint layers prepared in the examples and comparative examples was measured according to ASTM D3359. A BGD503 paint film adhesion grid plate was used as a guide device. 11 parallel cutting lines were cut on the coating surface at a uniform speed. Each cutting line should be cut to the substrate surface. The above operation was repeated to complete the longitudinal cutting. A 100-grid mesh cutting net was formed on the coating surface. A 3M tape with a width of 25 mm was adhered to the coating test area. After keeping it for one minute, a peeling test was performed to observe the shedding of the cut portion of the coating and evaluate the adhesion between the coating and the substrate.

[0091] Table 1 below shows the performance test results of the weather-resistant water-based two-component epoxy paints prepared in the examples and comparative examples:

[0092] Table 1

[0093]

[0094]

[0095] It can be seen from Table 1 above that the weather-resistant water-based two-component epoxy paints prepared in Examples 1 to 3 have good adhesion, and are strong in flexibility, weather resistance, water resistance, and corrosion resistance.

[0096] Comparative Example 1 is compared with Example 2. The water-based epoxy emulsion in Comparative Example 1 is modified with phytic acid, and the obtained weather-resistant water-based two-component epoxy paint has poor adhesion, and weak flexibility and corrosion resistance.

[0097] Compared with Example 2, Comparative Example 2 only uses silane coupling agent KH560 to modify nano-silica, and the obtained weather-resistant water-based two-component epoxy paint has poor adhesion, and weak flexibility and corrosion resistance.

[0098] Compared with Example 2, in Comparative Example 3, the modified curing agent of Comparative Example 3 does not add functionalized silicone, and the obtained weather-resistant water-based two-component epoxy paint has poor adhesion, and weak flexibility and corrosion resistance.

[0099] Comparative Example 4 is compared with Example 2. The silicone in Comparative Example 4 is not functionalized, and the obtained weather-resistant water-based two-component epoxy paint has poor adhesion and weak flexibility.

[0100] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A weather-resistant water-based two-component epoxy paint, characterized in that: It includes component A and component B; in terms of weight, the raw material components of component A include 50-70 parts by weight of modified waterborne epoxy emulsion, 3-6 parts by weight of pigment, 7-13 parts by weight of modified filler, 0.3-1.5 parts by weight of wetting dispersant, 2-4 parts by weight of film-forming aid, 0.1-0.5 parts by weight of defoamer, 0.5-5 parts by weight of water, and 0.5-1 parts by weight of leveling agent; the raw material components of component B include 35-65 parts by weight of modified curing agent, 10-20 parts by weight of ethanol, and 30-40 parts by weight of water.

2. The weather-resistant water-based two-component epoxy paint according to claim 1, characterized in that: Component A and component B are mixed in a mass ratio of 100:20-30.

3. The weather-resistant water-based two-component epoxy paint according to claim 1, characterized in that: The modified waterborne epoxy emulsion is a waterborne epoxy emulsion modified by phytic acid.

4. The weather-resistant water-based two-component epoxy paint according to claim 2, characterized in that: The modified filler is obtained by modifying nano silicon dioxide with poly-m-phenylenediamine and silane coupling agent KH560.

5. The weather-resistant water-based two-component epoxy paint according to claim 2, characterized in that: The modified curing agent is obtained by reacting polyethylene glycol diglycidyl ether, epoxy resin, triethylenetetramine, functionalized silicone and phenyl glycidyl ether, wherein the functionalized silicone is obtained by modifying hydrogenated silicone oil with allyl polyethylene glycol and allyl glycidyl ether.

6. A method for preparing a weather-resistant water-based two-component epoxy paint, characterized in that: The method comprises the following preparation steps: (1) Weighing the raw material components according to claim 1 in parts by weight; (2) putting the water, wetting dispersant and defoaming agent weighed in step (1) into a container, stirring at 80-120 r / min until the wetting dispersant is dissolved; then adding pigment and modified filler under stirring at 80-120 r / min, then dispersing at 1000-2000 r / min for 28-32 min, then adjusting the stirring speed to 80-120 r / min, adding modified waterborne epoxy emulsion, film-forming aid and leveling agent in sequence while stirring, and then stirring and dispersing at 300-500 r / min for 10-20 min to obtain component A, which is stored for later use; (3) placing the modified curing agent, ethanol and water weighed in step (1) into a container, and stirring and dispersing at 800 to 1200 r / min for 15 to 25 minutes; (4) Component A and component B are mixed at a mass ratio of 100:20-30 at 400-800 r / min for 20-40 min, left for 30 min, and then coated on the surface of the substrate using a roller coater. The coating is further cured at 100-110° C. for 25-35 min to obtain a weather-resistant water-based two-component epoxy paint with a thickness of 49.5-50.5 μm.

7. The method for preparing the weather-resistant water-based two-component epoxy paint according to claim 6, characterized in that: The preparation steps of the modified waterborne epoxy emulsion are as follows: 5 to 7 parts by weight of emulsifier and 4.2 to 4.4 parts by weight of phytic acid are stirred at 80 to 120 r / min for 29 to 31 minutes, then 18 to 22 parts by weight of epoxy resin and 2.3 to 2.5 parts by weight of ethylene glycol propyl ether are added, melted at 79 to 81° C. and stirred evenly, then the temperature is reduced to 39 to 41° C., and 18 to 20 parts by weight of deionized water are added dropwise at 1000 to 2000 r / min while stirring to obtain the modified waterborne epoxy emulsion.

8. The method for preparing the weather-resistant water-based two-component epoxy paint according to claim 6, characterized in that: The preparation steps of the modified curing agent are as follows: polyethylene glycol diglycidyl ether is heated to 64-66° C., and then triethylenetetramine is added dropwise, and the addition is completed within 30 minutes. The mixture is stirred at a stirring speed of 200-300 r / min and kept warm for 3.8-4.2 hours. The excess triethylenetetramine is then removed by rotary evaporation. Then, a propylene glycol methyl ether solution of epoxy resin with a concentration of 48-52% is added dropwise, and the addition is completed within 30 minutes. The reaction is continued by keeping warm for 2.8-3.2 hours, and then the functionalized silicone is added. The reaction was carried out for 28 to 32 minutes as a capping agent, and phenyl glycidyl ether was finally added, and the reaction was continued for 55 to 65 minutes. Deionized water was added to adjust the solid content of the system to 40 to 60%, and stirring was continued for 55 to 65 minutes to obtain a modified curing agent; wherein the molar ratio of polyethylene glycol diglycidyl ether, triethylenetetramine, epoxy group of epoxy resin, functionalized silicone, and phenyl glycidyl ether was 1:2 to 3:0.55 to 0.65:0.14 to 0.18:0.56 to 0.

72.

9. The method for preparing the weather-resistant water-based two-component epoxy paint according to claim 8, characterized in that: The preparation steps of the functionalized organic silicon are as follows: a toluene solution of allyl polyethylene glycol with a concentration of 10% and a chloroplatinic acid-isopropanol catalyst of 25 μg / g are mixed in a mass ratio of 1:0.05, and the mixture is heated to 74-76° C. for dehydration for 28-32 minutes; then, hydrogenated silicone oil is added dropwise, and the addition is completed within 28-32 minutes; the mixture is heated to 130-140° C., and after reacting for 2.5-3.5 hours, the reaction temperature is lowered to 84-86° C., allyl glycidyl ether is added, the reaction is continued for 3.5-4.5 hours, and then the toluene solvent is removed by rotary evaporation to obtain the functionalized organic silicon; wherein the molar ratio of allyl polyethylene glycol, silicon-hydrogen bonds in hydrogenated silicone oil, and allyl glycidyl ether is 0.7-0.8:1:0.2-0.

3.

10. The method for preparing the weather-resistant water-based two-component epoxy paint according to claim 6, characterized in that: The preparation steps of the modified filler are as follows: 2.5-2.7 parts by mass of tetraethyl orthosilicate, 47-49 parts by mass of anhydrous ethanol and 19-21 parts by mass of deionized water are preheated at 79-81° C. for 28-32 minutes under stirring at 400-600 r / min, pH is adjusted to 7.5-8.5 with ammonium hydroxide, reacted at 48-52° C. for 11-13 hours, 0.56-0.58 parts by mass of silane coupling agent KH560 is added, stirring is continued at 54-56° C. for 5.5-6.5 hours, washed with deionized water and anhydrous ethanol, centrifuged for 4-6 times, and vacuum dried at 100° C. for 12 hours to obtain nano-silica modified with silane coupling agent KH560; 0.4-0.6 parts by weight of m-phenylenediamine is added to 48-52 parts by weight of 0.6 mol / L ammonia water and ultrasonically treated for 28-32 minutes to obtain a m-phenylenediamine dispersion; 1.57-1.59 parts by weight of ammonium persulfate and 20 parts by weight of deionized water are mixed and stirred for 18-22 minutes, and the addition is completed within 30 minutes to obtain an initiator solution; under stirring in an ice water bath, the initiator solution is added dropwise to the m-phenylenediamine dispersion within 30 minutes, reacted at 29-31° C. for 5.5-6.5 hours, then centrifuged and repeatedly washed with deionized water and anhydrous ethanol to remove unreacted oligomers, and dried at 70° C. for 8 hours to obtain poly-m-phenylenediamine; 0.15-0.25 parts by weight of silane coupling agent KH560 modified nano-silica is dissolved in 50 parts by weight of acetone, and ultrasonically treated for 28-32 minutes to form a uniform silane coupling agent KH560 modified nano-silica dispersion; 0.2-0.3 parts by weight of poly-m-phenylenediamine is weighed and dispersed in 18-22 parts by weight of acetone, and then added to the silane coupling agent KH560 modified nano-silica dispersion, and reacted at 78-82° C. with magnetic stirring for 9.5-10.5 hours, and repeatedly washed with deionized water and centrifuged for 4-6 times, and dried to obtain a modified filler.

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