Modified radix asparagi polyurea intermediate paint for hydroelectric dam steel gate as well as preparation method and application of modified radix asparagi polyurea intermediate paint

Abstract

The invention discloses a modified radix asparagi polyurea intermediate paint for a hydroelectric dam steel gate as well as a preparation method and application thereof. The intermediate paint is prepared by mixing a component A and a component B according to a mass ratio of (3-5): 1; the component A comprises epoxy modified polyaspartic acid ester resin A, epoxy modified polyaspartic acid ester resin B, pigment, filler, a mixed solvent, a dispersing agent, a defoaming agent and a rheological additive; and the component B comprises an isocyanate mixture, a reactive diluent PEC and butyl acetate. The invention further discloses the preparation method of the modified polyaspartic polyurea intermediate paint for the hydroelectric dam steel gate. The modified radix asparagi polyurea intermediate paint for the hydroelectric dam steel gate is low in odor, the construction solid content is larger than 90%, the modified radix asparagi polyurea intermediate paint belongs to an environment-friendly green product, compared with an existing common thick-build epoxy intermediate paint, the drying speed is high, the ultraviolet aging resistance is good, the all-weather construction requirement of the wet-on-wet spraying technology can be met, and therefore the construction efficiency is greatly improved, and the construction cost is reduced. And a formed paint film is good in drawing adhesive force and excellent in mechanical property.

Description

Technical Field

[0001] The invention relates to an intermediate paint in the field of heavy corrosion protection of steel structures and a preparation method and application thereof, and in particular to a modified aspartame polyurea intermediate paint for steel gates of hydropower dams and a preparation method and application thereof. Background Art

[0002] Hydropower is one of the green energy sources that the country focuses on developing.

[0003] As an important component of hydraulic metal structure equipment, steel gates are exposed to long-term harsh environments such as alternating dry and wet conditions, high-speed water flow erosion, ultraviolet light exposure, sediment impact, industrial wastewater and aquatic biological corrosion, high temperature and humidity in summer, and freezing and thawing in winter, and are extremely prone to corrosion.

[0004] Scientific and reasonable steel gate anti-corrosion technology can reduce the maintenance cost of steel gate equipment, which is conducive to better performance of power plant benefits. It is one of the key technologies to ensure the reliable operation and durable use of steel gate equipment.

[0005] At present, most of the protection in the field of heavy-duty anti-corrosion technology for steel structures is based on a composite coating system, typically epoxy zinc-rich primer + epoxy intermediate paint + acrylic polyurethane topcoat. The anti-corrosion performance of this composite coating system has been verified by long-term market application, but it has defects such as slow drying speed of epoxy intermediate paint, thick film cannot be wet-to-wet construction with subsequent topcoat, and low construction efficiency; at the same time, epoxy intermediate paint has poor gloss and color retention and UV resistance, and it is easy to powder and turn white, which is not suitable for long-term outdoor placement after construction and then spraying topcoat; in addition, epoxy intermediate paint can only prepare rigid coatings, with limited flexibility adjustment, and average wear resistance and erosion resistance.

[0006] Asparagus polyurea coating is a new type of coating material with high reactivity, high performance, high solid and low viscosity, also known as the third generation of polyurea coating. It can form a high cross-linking density and high wear resistance coating film, which has excellent hardness and flexibility, bending resistance, stone impact resistance, tensile strength, and good long-term anti-corrosion performance. Compared with traditional thick paste epoxy intermediate paint, asparagus polyurea intermediate paint has the advantages of fast curing, mechanical properties of both rigidity and flexibility, and high construction efficiency. This type of coating has been added to the latest version of "ISO12944-5:2018 Paints and varnishes-Corrosion protection of steel structures by protective paint systems". However, at present, asparagus polyurea coating is mainly used as a topcoat or a primer-top coating, and there is no report of using it as an intermediate paint.

[0007] CN117363200A discloses a high-solid bio-based polyurethane intermediate paint and its preparation method, which solves the problems of slow drying speed and difficulty in low-temperature curing of traditional epoxy iron oxide intermediate paint to a certain extent, but the drying speed is still slow, and it takes 1 hour for surface drying and 18 hours for actual drying, which cannot meet the requirements of wet-on-wet construction process; in addition, the flexibility is poor and it is not suitable for anti-corrosion of steel gates of hydropower dams. Zhang Yuying et al. reported in the article "Development and Application of Fluorosilicone Modified Asparagus Polyurea Anti-Ice Pulling Coating for Hydropower Dams" (see "China Coatings" 2022 Issue 09) that solvent-free asparagus polyurea intermediate coating is used, which has good flexibility. However, the drying speed is still slow, and it is not suitable for wet-on-wet spraying with subsequent topcoats; the adhesion is 3.5MPa, which cannot meet the requirements of adhesion ≥7MPa in "HG / T5368-2018 Polyaspartic Acid Anticorrosive Coating"; the intermediate coating is mainly used for hydropower dam concrete substrates, and is not suitable for anti-corrosion of hydropower dam steel gates. Meng Zhaohui et al. reported in the article “Research and Development of a High-Solid Polyurea Automotive Midcoat” (see Tianjin Science and Technology, Issue 07, 2009) that the polyurea midcoat they developed is suitable for the drying production line of the automotive industry. It has low solid content during construction and low sagging film thickness (55μm); however, it cannot meet the requirements of self-drying coating of hydropower dam steel gates, which require a one-time film formation of more than 160μm. Summary of the invention

[0008] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a modified asparagus polyurea intermediate paint for hydropower dam steel gates that is wear-resistant, scour-resistant, has both rigid and flexible paint film mechanical properties, good adhesion, can form a film of more than 160μm in one time, has a fast drying speed, is suitable for wet-on-wet spraying of subsequent coatings, has high construction efficiency, and has excellent aging performance.

[0009] The technical solution adopted by the present invention to solve the technical problem is: a modified aspartic polyurea intermediate paint for a hydropower dam steel gate comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 3 to 5:1; the component A comprises an epoxy-modified polyaspartic acid ester resin A, an epoxy-modified polyaspartic acid ester resin B, a dispersant, a defoamer, a mixed solvent, a rheological additive, a molecular sieve dewatering agent, a pigment, and a filler; the component B comprises an isocyanate mixture, a reactive diluent PEC, and butyl acetate;

[0010] The component A comprises 20 to 25 parts of epoxy-modified polyaspartic acid ester resin A, 10 to 12.5 parts of epoxy-modified polyaspartic acid ester resin B, 1 to 1.5 parts of dispersant, 0.2 to 0.5 parts of defoamer, 5 to 7 parts of mixed solvent, 0.5 to 1.5 parts of rheological additive, 3 to 5 parts of molecular sieve dewatering agent, 10 to 15 parts of titanium dioxide, 0 to 0.3 parts of carbon black, 10 to 20 parts of talc, 15 to 20 parts of quasi-spherical silica powder, and 5 to 10 parts of wet-process sericite, wherein the titanium dioxide, carbon black, talc, quasi-spherical silica powder and wet-process sericite are pigments and fillers; the component B comprises 90 to 96 parts of isocyanate mixture, 2 to 5 parts of active diluent PEC, and 2 to 6 parts of butyl acetate;

[0011] The preparation methods of the epoxy-modified polyaspartic acid ester resin A and the epoxy-modified polyaspartic acid ester resin B are as follows: epoxy resin is added to polyaspartic acid ester resin, and epoxy ring-opening and end-capping reaction is performed to obtain the epoxy-modified polyaspartic acid ester resin.

[0012] The component A in the modified aspartic acid polyurea intermediate paint for the steel gate of the hydropower dam of the present invention is mainly used as the base material. By compounding epoxy-modified polyaspartic acid resin A and epoxy-modified polyaspartic acid resin B with different reaction activities, the two are coordinated with each other in a specific ratio to achieve a balance in drying speed and activation period, and rapid curing is achieved while ensuring that the modified aspartic acid polyurea intermediate paint has sufficient time to wet with the previous coating, so that the formed coating has high matching adhesion. The purpose of the present invention to epoxy-modify the polyaspartic acid resin is to introduce the residual primary amine in the epoxy resin and the polyaspartic acid resin into the polyaspartic acid resin by using the ring-opening reaction, thereby reducing the irritating amine taste, enhancing the anti-corrosion and salt spray resistance, extending the service life, and improving the interlayer matching performance between the previous epoxy coating and the subsequent polyaspartic acid topcoat, so as to better play the role of the intermediate paint as a link between the upper and lower layers.

[0013] The component B in the modified asparagine polyurea intermediate paint for the steel gate of the hydropower dam of the present invention is mainly used as a curing agent, and the isocyanate mixture therein is formed by compounding HDI asymmetric trimer and HDI dimer. The traditional HDI standard trimer isocyanate curing agent has a large viscosity and is difficult to meet the construction solid content requirement of the modified asparagine polyurea intermediate paint for the steel gate of the hydropower dam of the present invention of >90%. Due to its asymmetric structure, the HDI asymmetric trimer has a lower viscosity and a higher NCO content than the standard trimer curing agent. At the same time, because its functionality is greater than 3, it can provide sufficient crosslinking density and excellent drying performance to obtain a coating with high hardness. HDI dimer has very low viscosity and good flexibility due to its dimer structure. The obtained coating has good flexibility and elasticity, and is particularly suitable for use with HDI trimer to increase the construction solid content and reduce the system VOC. However, since its functionality is lower than that of trimer, as the proportion of HDI dimer added increases, it will have a certain impact on the drying performance and anti-corrosion performance of the paint film, so its proportion needs to be reasonably controlled according to performance requirements. Preferably, the HDI asymmetric trimer and HDI dimer in the isocyanate mixture are mixed in a mass ratio of 0.5 to 1.5:1, wherein the HDI asymmetric trimer is one or more of HT-500, HT-300, and N3900, and the HDI dimer is one or more of HT-400 and N3400.

[0014] The active diluent PEC in the modified aspartic polyurea intermediate paint for hydropower dam steel gates of the present invention can undergo a ring-opening reaction with the secondary amino group -NH in the modified polyaspartic acid ester resin, replacing part of -NH with -OH, thereby reducing the reaction activity and extending the application period. However, if added too much, it will have an adverse effect on the drying speed and the hardness of the coating film. Therefore, preferably, the amount of PEC added in the component B is 2 to 5 parts.

[0015] The present invention comprises component A comprising epoxy-modified polyaspartic acid ester resin A and epoxy-modified polyaspartic acid ester resin B with different activities, and component B comprising HDI asymmetric trimer and HDI dimer with different structures. Component A is then mixed with component B to carry out a crosslinking and curing reaction. Therefore, several types of chemical reactions exist in the coating system at the same time, and different types of crosslinking are formed, thereby obtaining a three-dimensional interpenetrating network (IPN) and achieving a synergistic effect.

[0016] Furthermore, the raw material polyaspartic acid ester resin for preparing epoxy-modified polyaspartic acid ester resin A in component A is one or more of F421, NH1420, NH2886, and K8428, and the raw material polyaspartic acid ester resin for preparing epoxy-modified polyaspartic acid ester resin B is one or more of F520, NH1520, and K8520.

[0017] Furthermore, the raw material epoxy resin for preparing epoxy-modified polyaspartic acid ester resin A and epoxy-modified polyaspartic acid ester resin B in component A is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

[0018] Furthermore, in the preparation method of the epoxy-modified polyaspartic acid ester resin A and the epoxy-modified polyaspartic acid ester resin B in the component A, the mass ratio of the polyaspartic acid ester resin to the epoxy resin is 10:0.2-0.9.

[0019] Furthermore, in the preparation method of the epoxy-modified polyaspartic acid ester resin A and the epoxy-modified polyaspartic acid ester resin B in the component A, the reaction temperature is 60-80°C; and the reaction time is 6-8h. If the reaction temperature is too low, the raw materials will not react completely; if the reaction temperature is too high, the resin will self-polymerize, thereby affecting the product quality; if the reaction time is too short, the raw materials will not react completely; if the reaction time is too long, it will cause energy waste and affect production efficiency.

[0020] Furthermore, in the component A, the dispersant is one or more of BYK-163, BD-8343, and AFCONA4071, the defoamer is one or more of the non-silicon defoamers BYK-066N, BYK-054, and BYK-1790, and the mixed solvent is a mixture of xylene and butyl acetate in a mass ratio of 1:1.

[0021] Furthermore, in the component A, the rheological additive is German Levos polyamide wax powder PAB, because it has 100% solid content, good anti-sagging performance, little effect on viscosity, and is easy to activate and add.

[0022] Furthermore, in the component A, the molecular sieve dehydrating agent is American Grace SYLOSIV A3 molecular sieve, and the titanium dioxide crystal type is anatase type.

[0023] Furthermore, in the component A, the talc is preferably a low-viscosity flaky talc with a particle size of 325 mesh. When a talc with a larger particle size of 325 mesh is used, the viscosity of the paint is low and the interlayer matching is good, because the microscopic coating obtained by the larger particle size is relatively rough, and the intermediate paint film has an appropriate roughness, which is more conducive to improving the interlayer adhesion between the primer and the topcoat. In addition, the larger the particle size of the flaky talc, the larger the diameter-to-thickness ratio, the better the shielding effect and anti-penetration performance, and the relatively better salt spray resistance. Large-layer talc is conducive to improving the corrosion resistance and salt spray resistance of the paint film.

[0024] Furthermore, in the component A, the particle size of the quasi-spherical silica powder is 800 mesh, and the wet-process sericite is GA-6 produced by Anhui Gerui.

[0025] The method for preparing the modified aspartame polyurea intermediate paint for the hydropower dam steel gate comprises the following steps:

[0026] (1) Preparation of component A: using a high-speed stirring and dispersing process, under a stirring speed of 300-500 r / min, epoxy-modified polyaspartic acid ester resin A, epoxy-modified polyaspartic acid ester resin B, dispersant, defoamer, 50% mixed solvent and rheological additive are added in order according to the formula amount, and stirred evenly. Then, molecular sieve dehydrating agent, titanium dioxide, carbon black, talcum powder and quasi-spherical silica powder are added in order according to the formula amount. After stirring evenly, the speed is increased to 2000-2500 r / min and stirred until the temperature reaches 50-60° C. and the mixture is stirred at this temperature for 30-60 minutes. Finally, the remaining mixed solvent and wet-process sericite are added and stirred at 600-800 r / min for 30 minutes.

[0027] (2) Preparation of component B: Add isocyanate mixture, reactive diluent PEC, and butyl acetate in order according to the formula amount, and stir at a speed of 300-500 r / min for 10-15 minutes until uniform;

[0028] (3) When in use, the component A obtained in step (1) and the component B obtained in step (2) are mixed evenly in a mass ratio of 3 to 5:1 to obtain a modified aspartame polyurea intermediate paint for a steel gate of a hydropower dam.

[0029] The modified aspartame polyurea intermediate paint for the steel gate of the hydropower dam is applied to the surface of the steel gate of the hydropower dam to form an anti-corrosion coating.

[0030] Compared with the existing related intermediate paints, the modified aspartic acid polyurea intermediate paint for hydropower dam steel gates of the present invention has the following beneficial effects: (1) by epoxy-modifying and compounding the polyaspartic acid ester resins with different activities in component A, and compounding the isocyanates with different structures in component B, and then mixing component A with component B for cross-linking and curing reaction, different types of cross-linking chemical reactions are formed to obtain a three-dimensional interpenetrating network structure (IPN), which is applied to hydropower dam steel gates and exhibits unique properties: wear resistance and water flow impact resistance, the paint film is both hard and soft, and the adhesion is greater than 13MPa. As an intermediate paint, it has good matching performance with primer and topcoat, good UV aging resistance, low product odor, construction solid content greater than 90%, a one-time film formation of more than 160μm, fast drying speed, surface drying time not exceeding 25min, and actual drying time not exceeding 3.5h; it is a green and environmentally friendly product; (2) it can be used in conjunction with the subsequent topcoat for wet-on-wet all-weather construction, and has high construction efficiency. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technical solutions realized based on the content of the present invention belong to the scope of the present invention.

[0032] The raw materials polyaspartic acid ester resin F421 and F520 used in the embodiment of the present invention were purchased from Feiyang Chemical, NH2886, NH1420, and NH1520 were purchased from Covestro, K8428 and K8520 were purchased from Guangzhou Jinboer Chemical, bisphenol A epoxy resin E-51 and phenolic epoxy resin F51 were purchased from Jiangsu Sanmu Chemical, and bisphenol F epoxy resin 2633 was purchased from Hansen Chemical; dispersants BYK-163, BD-8343, and AFCONA4071 were purchased from BYK, Foshan Better Chemical, and AFCONA, respectively; defoamers BYK-066N, BYK-054, and BYK-1790 were purchased from BYK; polyamide wax powder PAB was purchased from Germany Levos; molecular sieve dewatering agent SYLOSIV A3 was purchased from Grace, USA; talc was purchased from Quanzhou Xufeng Powder Raw Material Co., Ltd.; quasi-spherical silica powder was purchased from Hunan Jinma New Materials; wet-process sericite GA-6 was purchased from Anhui Ge Rui; isocyanates N3900 and N3400 were purchased from Covestro; isocyanates HT-500, HT-300, and HT-400 were purchased from Wanhua Chemical; and active diluent PEC was purchased from Polymicro Coating Additives.

[0033] Unless otherwise specified, the chemical reagents used in the embodiments of the present invention were obtained through conventional commercial channels.

[0034] Preparation Example 1 of the Modified Asparagus Polyurea Intermediate Paint for Hydropower Dam Steel Gate of the Present Invention

[0035] In this embodiment, epoxy-modified polyaspartic acid ester resin is first prepared, and then the coating is prepared, which specifically includes the following steps:

[0036] (1) Preparation of epoxy-modified polyaspartic acid ester resin A: 14 parts by weight of E51 were added to 700 parts by weight of F421 to carry out epoxy ring-opening and end-capping reaction at 80° C. for 6 hours to obtain the obtained product;

[0037] (2) Preparation of epoxy-modified polyaspartic acid ester resin B: 14 parts by weight of E51 were added to 700 parts by weight of F520 to carry out epoxy ring-opening and end-capping reaction at 80° C. for 6 hours to obtain the obtained product;

[0038] (3) Preparation of Component A: Using a high-speed stirring and dispersing process, under stirring at a speed of 400 r / min, add 20 parts of epoxy-modified polyaspartic acid ester resin A, 10 parts of epoxy-modified polyaspartic acid ester resin B, 1 part of dispersant BYK-163, 0.2 parts of defoamer BYK-066N, 2.5 parts of mixed solvent, and 0.5 parts of rheological additive PAB in order according to the formula amount, stir evenly, then add 3 parts of molecular sieve dehydrating agent SYLOSIV A3, 15 parts of titanium dioxide, 20 parts of talc, and 20 parts of quasi-spherical silica powder in order according to the formula amount, stir evenly, increase the speed to 2500 r / min, stir until the temperature reaches 50°C, and keep stirring for 60 minutes, finally add the remaining 2.5 parts of mixed solvent and 5.3 parts of wet-process sericite GA-6, and stir at 800 r / min for 30 minutes to complete;

[0039] (4) Preparation of component B: Add 60 parts of HT-500, 35 parts of HT-400, 2 parts of active diluent PEC, and 3 parts of butyl acetate in order according to the formula, and stir at 300 r / min for 15 minutes until uniform;

[0040] (5) When in use, the component A obtained in step (3) and the component B obtained in step (4) are mixed in a mass ratio of 5:1.

[0041] Preparation Example 2 of Modified Asparagus Polyurea Intermediate Paint for Hydropower Dam Steel Gate

[0042] In this embodiment, epoxy-modified polyaspartic acid ester resin is first prepared, and then the coating is prepared, which specifically includes the following steps:

[0043] (1) Preparation of epoxy-modified polyaspartic acid ester resin A: 42 parts by weight of F51 were added to 700 parts by weight of NH1420 to carry out epoxy ring-opening and end-capping reaction, and the reaction was carried out at 70° C. for 6.5 hours to obtain the obtained product;

[0044] (2) Preparation of epoxy-modified polyaspartic acid ester resin B: 42 parts by weight of F51 were added to 700 parts by weight of F524 to carry out epoxy ring-opening and end-capping reaction at 70° C. for 6.5 hours to obtain the obtained product;

[0045] (3) Preparation of Component A: Using a high-speed stirring and dispersing process, under a stirring speed of 500 r / min, 22 parts of epoxy-modified polyaspartic acid ester resin A, 11.5 parts of epoxy-modified polyaspartic acid ester resin B, 1 part of dispersant BD-8343, 0.3 parts of defoamer BYK-054, 3 parts of mixed solvent, and 1 part of rheological additive PAB were added in sequence according to the formula amount, and stirred evenly. Then, 4 parts of molecular sieve dehydrating agent SYLOSIV A3, 10 parts of titanium dioxide, 0.3 parts of carbon black, 18 parts of talc, and 17.5 parts of quasi-spherical silica powder were added in sequence according to the formula amount. After stirring evenly, the speed was increased to 2000 r / min and stirred until the temperature reached 60°C and kept stirring for 30 minutes. Finally, the remaining 3 parts of mixed solvent and 8.4 parts of wet-process sericite GA-6 were added and stirred at 600 r / min for 30 minutes.

[0046] (4) Preparation of component B: Add 45 parts of N3900, 45 parts of N3400, 4 parts of active diluent PEC, and 6 parts of butyl acetate in order according to the formula, and stir at 500 r / min for 10 minutes until uniform;

[0047] (5) When in use, the component A obtained in step (3) and the component B obtained in step (4) are mixed in a mass ratio of 4:1.

[0048] Preparation Example 3 of Modified Asparagus Polyurea Intermediate Paint for Hydropower Dam Steel Gate

[0049] In this embodiment, epoxy-modified polyaspartic acid ester resin is first prepared, and then the coating is prepared, which specifically includes the following steps:

[0050] (1) Preparation of epoxy-modified polyaspartic acid ester resin A: 63 parts by weight of 2633 were added to 700 parts by weight of K8428 to carry out epoxy ring-opening and end-capping reaction, and the reaction was carried out at 60° C. for 8 hours to obtain the obtained product;

[0051] (2) Preparation of epoxy-modified polyaspartic acid ester resin B: 63 parts by weight of 2633 were added to 700 parts by weight of K8520 to carry out epoxy ring-opening and end-capping reaction, and the reaction was carried out at 60° C. for 8 hours to obtain the obtained product;

[0052] (3) Preparation of Component A: Using a high-speed stirring and dispersing process, under a stirring speed of 300 r / min, add 25 parts of epoxy-modified polyaspartic acid ester resin A, 12.5 parts of epoxy-modified polyaspartic acid ester resin B, 1.5 parts of dispersant AFCONA4071, 0.4 parts of defoamer BYK-1790, 3.5 parts of mixed solvent, and 1.5 parts of rheological additive PAB in order according to the formula amount, stir evenly, then add 5 parts of molecular sieve dehydrating agent SYLOSIV A3, 13 parts of titanium dioxide, 0.1 parts of carbon black, 10 parts of talc, and 15 parts of quasi-spherical silica powder in order according to the formula amount, stir evenly, increase the speed to 2200 r / min, stir until the temperature reaches 55°C, and keep stirring for 45 minutes, finally add the remaining 3.5 parts of mixed solvent and 9 parts of wet-process sericite GA-6, and stir at 700 r / min for 30 minutes.

[0053] (4) Preparation of component B: Add 30 parts of HT-300, 60 parts of N3400, 5 parts of active diluent PEC, and 5 parts of butyl acetate in order according to the formula, and stir at 400 r / min for 12 minutes until uniform;

[0054] (5) When in use, the component A obtained in step (3) and the component B obtained in step (4) are mixed in a mass ratio of 3:1.

[0055] Comparative Example 1

[0056] An aspartame polyurea intermediate paint comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 3:1. The component A is different from the component A in Example 3 only in that the epoxy-modified polyaspartic acid ester resin A is replaced by an equal amount of K8428, and the epoxy-modified polyaspartic acid ester resin B is replaced by an equal amount of K8520. The component B is the same as the component B in Example 3. Meanwhile, the preparation process of the components A and B in Comparative Example 1 is the same as that in Example 3.

[0057] Comparative Example 2

[0058] A asparagus polyurea intermediate paint comprises a component A and a component B, wherein the mass ratio of the component A to the component B is 4:1. The component A is the same as the component A in Example 2. The component B is different from the component B in Example 2 only in that 45 parts of HDI asymmetric trimer N3900 and 45 parts of HDI dimer N3400 are replaced by 90 parts of HDI asymmetric trimer N3900 in equal amounts. Meanwhile, the preparation process of the components A and B in Comparative Example 2 is the same as that in Example 2.

[0059] Comparative Example 3

[0060] Commercially available high build epoxy intermediate coating.

[0061] Examples 1 to 3 and comparative examples 1 to 3 were tested and compared, and the results are shown in Table 1.

[0062] Table 1 Test results of coating properties of Examples 1 to 3 of the present invention and Comparative Examples 1 to 3

[0063]

[0064]

[0065] From Table 1, we can see that:

[0066] Comparing Comparative Example 1 with Example 3, after the polyaspartic acid ester resin is modified with epoxy resin, the irritating amine taste can be reduced, the anti-corrosion and salt spray resistance can be enhanced, the service life can be extended, and the supporting adhesion can be improved;

[0067] Comparing Comparative Example 2 with Example 2, after the isocyanate in component B is mixed with HDI asymmetric trimer and HDI dimer, the bending performance, flexibility, wear resistance and pull-off adhesion of the coating are all improved, indicating that the coating forms a unique three-dimensional network structure after mixing, which improves the mechanical properties of the paint film. At the same time, thanks to the ultra-low viscosity of HDI dimer, the construction solid content is also improved;

[0068] Comparing Comparative Example 3 with Examples 1 to 3, the drying speed of the examples is greatly improved, which can meet the requirements of wet-on-wet spraying of the subsequent coating, and the construction efficiency is greatly improved. At the same time, the mechanical properties of the paint film, such as flexibility, impact resistance, and wear resistance, are better than those of Comparative Example 3, and the artificial accelerated aging is also significantly better than that of Comparative Example 3, which is more suitable for the protection of the steel gates of hydropower dams in corrosive environments.

[0069] See Table 2 for an overall solution embodiment of a coating system that is compatible with the modified asparagus polyurea intermediate paint for the hydropower dam steel gate of the present invention.

[0070] Table 2 Coating system for steel gates of hydropower dams

[0071] Coating system Anti-corrosion layer type Thickness / μm Zinc spraying layer Zinc 160(minimum local thickness) Sealing layer Epoxy sealer primer 50 Middle Layer Epoxy modified aspartame polyurea intermediate paint 160 Surface Polyaspartic acid polyurea topcoat 80 Total thickness 450

[0072] The middle layer in Table 2 - epoxy modified aspartame polyurea intermediate paint, is the modified aspartame polyurea intermediate paint for the steel gate of the hydropower dam of the present invention, and the construction thickness is 160 μm.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A modified aspartame polyurea intermediate paint for hydropower dam steel gates, characterized in that: The invention comprises component A and component B, wherein the mass ratio of component A to component B is 3 to 5:1; the component A comprises epoxy-modified polyaspartic acid ester resin A, epoxy-modified polyaspartic acid ester resin B, dispersant, defoamer, mixed solvent, rheological additive, molecular sieve dewatering agent, pigment and filler; the component B comprises isocyanate mixture, active diluent PEC and butyl acetate; The component A comprises 20 to 25 parts of epoxy-modified polyaspartic acid ester resin A, 10 to 12.5 parts of epoxy-modified polyaspartic acid ester resin B, 1 to 1.5 parts of dispersant, 0.2 to 0.5 parts of defoamer, 5 to 7 parts of mixed solvent, 0.5 to 1.5 parts of rheological additive, 3 to 5 parts of molecular sieve dewatering agent, 10 to 15 parts of titanium dioxide, 0 to 0.3 parts of carbon black, 10 to 20 parts of talc, 15 to 20 parts of quasi-spherical silica powder, and 5 to 10 parts of wet-process sericite; the component B comprises 90 to 96 parts of isocyanate mixture, 2 to 5 parts of active diluent PEC, and 2 to 6 parts of butyl acetate; The preparation methods of the epoxy-modified polyaspartic acid ester resin A and the epoxy-modified polyaspartic acid ester resin B are as follows: epoxy resin is added to polyaspartic acid ester resin, and epoxy ring-opening and end-capping reaction is performed to obtain the epoxy-modified polyaspartic acid ester resin.

2. The modified aspartame polyurea intermediate paint for hydropower dam steel gate according to claim 1, characterized in that: The raw material polyaspartic acid ester resin for preparing the epoxy-modified polyaspartic acid ester resin A in component A is one or more of F421, NH1420, NH2886, and K8428, and the raw material polyaspartic acid ester resin for preparing the epoxy-modified polyaspartic acid ester resin B in component A is one or more of F521, F524, and K8520.

3. The modified aspartame polyurea intermediate paint for hydropower dam steel gate according to claim 1 or 2, characterized in that: The raw material epoxy resin for preparing epoxy-modified polyaspartic acid ester resin A and epoxy-modified polyaspartic acid ester resin B in component A is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin and novolac epoxy resin.

4. The modified aspartame polyurea intermediate paint for hydropower dam steel gate according to claim 1 or 2, characterized in that: In the preparation method of epoxy-modified polyaspartic acid ester resin A and epoxy-modified polyaspartic acid ester resin B, the mass ratio of the polyaspartic acid ester resin to the epoxy resin is 10:0.2-0.

9.

5. The modified aspartame polyurea intermediate paint for hydropower dam steel gate according to claim 1 or 2, characterized in that: In the preparation method of epoxy-modified polyaspartic acid ester resin A and epoxy-modified polyaspartic acid ester resin B, the reaction temperature is 60-80° C. and the reaction time is 6-8 hours.

6. The modified aspartame polyurea intermediate paint for hydropower dam steel gate according to claim 1 or 2, characterized in that: In the component A, the dispersant is one or more of BYK-163, BD-8343, and AFCONA4071, the defoamer is one or more of the non-silicon defoamers BYK-066N, BYK-054, and BYK-1790, the mixed solvent is xylene and butyl acetate mixed in a mass ratio of 1:1, the rheological additive is German Levs polyamide wax powder PAB, the molecular sieve dehydrating agent is American Grace SYLOSIVA3 molecular sieve, the titanium dioxide crystal form is anatase type, the talc powder is a low-viscosity flaky structure talc powder with a preferred particle size of 325 meshes, the quasi-spherical silica powder has a particle size of 800 meshes, and the wet-process sericite is Anhui Ge Rui's GA-6; the active diluent PEC in the component B has a viscosity of 0.5-2 mPa·s, a boiling point of 240-250°C, and a molecular structure formula of an oxygen-containing five-ring structure.

7. The modified aspartame polyurea intermediate paint for hydropower dam steel gate according to claim 1 is characterized in that: In the component B, the isocyanate mixture is a mixture of HDI asymmetric trimer and HDI dimer in a mass ratio of 0.5 to 1.5:1, wherein the HDI asymmetric trimer is one or more of HT-500, HT-300, and N3900, and the HDI dimer is one or more of HT-400 and N3400.

8. A method for preparing a modified aspartame polyurea intermediate paint for a hydropower dam steel gate as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Preparation of component A: using a high-speed stirring and dispersing process, under a stirring speed of 300-500 r / min, epoxy-modified polyaspartic acid ester resin A, epoxy-modified polyaspartic acid ester resin B, dispersant, defoamer, 50% mixed solvent and rheological additive are added in order according to the formula amount, and stirred evenly. Then, molecular sieve dehydrating agent, titanium dioxide, carbon black, talcum powder and quasi-spherical silica powder are added in order according to the formula amount. After stirring evenly, the speed is increased to 2000-2500 r / min and stirred until the temperature reaches 50-60° C. and the mixture is stirred at this temperature for 30-60 minutes. Finally, the remaining mixed solvent and wet-process sericite are added and stirred at 600-800 r / min for 30 minutes. (2) Preparation of component B: Add isocyanate mixture, reactive diluent PEC, and butyl acetate in order according to the formula amount, and stir at a speed of 300-500 r / min for 10-15 minutes until uniform; (3) When in use, the component A obtained in step (1) and the component B obtained in step (2) are mixed evenly in a mass ratio of 3 to 5:1 to obtain a modified aspartame polyurea intermediate paint for a steel gate of a hydropower dam.

9. The modified aspartame polyurea intermediate paint according to any one of claims 1 to 7, characterized in that: It is used as an intermediate paint to form an anti-corrosion coating on the surface of steel gates of hydropower dams.

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