High crack following epoxy coating for concrete, coating layer, method for preparing the same, and application thereof

Abstract

The application discloses high-crack-following epoxy paint for concrete, a coating layer, a preparation method and application thereof. The high-crack-following epoxy paint comprises an A component composed of G-clay modified epoxy resin, polydopamine, a polymer elastomer, a wetting dispersant, a grafting coupling agent, an anti-settling agent, a pigment and filler, butanol and dimethylbenzene, and a B component composed of a flexible curing agent, butanol and dimethylbenzene. The A component and the B component are uniformly mixed to obtain the high-crack-following epoxy paint for concrete. The application further discloses a high-crack-following epoxy coating layer formed by curing the high-crack-following epoxy paint for concrete. The high-crack-following epoxy paint for concrete and the high-crack-following epoxy coating layer have excellent high-crack-following property and have application prospects in the field of concrete structure engineering in C5 harsh environment.

Description

TECHNICAL FIELD

[0001] The present application relates to a high-crack-following epoxy coating for concrete, an epoxy coating and a preparation method and application thereof, and belongs to the technical field of concrete surface protection. BACKGROUND

[0002] Investigation shows that by the end of 2020, there are more than 900,000 existing highway bridges in China, with a total length of 160,000 kilometers of expressways, and 2,375 port berths of 10,000 tons or more, of which 80% have been in service for more than 10 years. A large number of concrete structures are inevitably served in harsh and complex environments (especially coastal environments), and these environmental factors (such as temperature, humidity, precipitation, erosive ions, ultraviolet light, etc.) and load action will cause concrete cracking and steel corrosion, which has a very adverse effect on the mechanical properties and durability of the structure. Therefore, concrete structures that have been in service for about ten years generally have varying degrees of corrosion problems, nearly 50% of which need to be overhauled, forming a huge market for concrete structure maintenance.

[0003] Experience from developed countries shows that by brushing or spraying corrosion-resistant and anti-permeation coatings on the surface of concrete, the microcracks and pores on the surface of concrete can be efficiently repaired, and some water molecules, air, and salt ions can be isolated, reducing the damage of corrosion factors to concrete. This can effectively extend the service life of concrete structures by 30-50 years, which is a very cost-effective investment.

[0004] The penetration of ions and microcracks caused by stress cracking of concrete are closely related. The existing concrete protective coatings on the market do not have high crack-following properties. After the concrete develops microcracks under various factors, the corrosion of steel bars caused by the erosion of chloride ions and sulfur ions along the microcracks is one of the main reasons for the long-term service performance degradation of reinforced concrete structures.

[0005] Currently, some patents have also begun to focus on crack following function, such as comparative document 1 (CN102286137A) discloses a preparation method of marine concrete coating polyether modified epoxy resin. First, ring opening reaction of epoxy resin and acrylic acid is carried out to prepare epoxy modified acrylic resin. Then, addition reaction of diisocyanate and polyether is carried out to prepare isocyanate containing prepolymer. Isocyanate prepolymer and epoxy group and acrylic acid hydroxyl group on the epoxy modified acrylic resin react to form interpenetrating network polymer. The essence of the reaction is epoxy modified acrylic polyurethane polymer, not epoxy resin polymer. The main reliance is the good toughness of polyether modified isocyanate. But isocyanate is sensitive to water vapor, and marine concrete environment is often humid and water vapor coexists, which will affect the curing effect. Comparative document 2 (CN104497681A) discloses an epoxy elastic putty for concrete surface. Dimer acid glycidyl ester modified bisphenol A epoxy resin and liquid bisphenol A epoxy resin are used in combination. The long alkane chain introduced in the dimer acid glycidyl ester modified bisphenol A epoxy resin reduces the rigidity of the epoxy resin. At the same time, due to the introduction of dimer acid, the relative molecular mass of the polymer between the two crosslinking points is increased, the crosslinking density is reduced, and the toughness of the putty is increased. Polyamide and polyether amine are used in combination to increase the durability of toughness. The coating crosslinking density of this scheme is low. Since the putty is applied by scraping and polishing process, this scheme is suitable for making putty, but not suitable for coating. Comparative document 3 (CN107129664A) discloses a preparation method for toughening epoxy resin by forming a network based on bio-based dihydrocoumarin. Polyethylene glycol glycidyl ether and n-butyl glycidyl ether are alternately copolymerized with dihydrocoumarin under the catalysis of bis(triphenylphosphonio)ammonium chloride and chromium chloride to form a network structure mixed liquid. Then the above liquid mixture is added to the epoxy resin monomer, and cured with a curing agent and an accelerator to form a film. The toughness provided by the bio-based network modification is limited in improving the rigidity of the epoxy coating. Comparative document 4 (CN111592816A) discloses a high ductility epoxy resin anticorrosive coating for reinforced concrete surface and a preparation method thereof. First, polyether polyol is added to toluene-2,4-diisocyanate under certain reaction conditions to prepare polyurethane prepolymer. Then, ring opening reaction of the prepolymer and epoxy resin makes polyurethane and epoxy resin form interpenetrating network structure, which has toughening and strengthening effect on the substrate. The cost of this scheme is high, which is difficult to popularize and apply. Comparative document 5 (CN111794548A) discloses a reinforced concrete crack following coating system and its anticorrosion application. It is a bottom middle surface matching coating system, which belongs to the conventional matching idea of reinforced concrete coating.

[0006] Therefore, it is of great significance to research and develop a high cost performance epoxy coating which can realize high crack following of concrete substrate and has important significance for corrosion protection and service life extension of concrete structure engineering. SUMMARY

[0007] The main purpose of the present application is to provide a high crack following epoxy coating for concrete, coating, its preparation method and application to overcome the shortcomings of the prior art.

[0008] To achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application comprises:

[0009] The G-clay modified epoxy resin provided by the embodiment of the present application is prepared by ion exchange reaction of a compound with primary amine groups and quaternary ammonium salt cations on nano-clay to obtain a reactive G-clay, and then uniformly dispersing the G-clay into an epoxy resin.

[0010] The embodiment of the present application also provides a preparation method of the G-clay modified epoxy resin, which comprises:

[0011] (1) mixing a solvent and nano-clay and stirring uniformly to form a first mixture;

[0012] (2) adding a compound with primary amine groups and quaternary ammonium salt cations to the upper suspension of the first mixture to perform ion exchange reaction of the nano-clay and the compound with primary amine groups and quaternary ammonium salt cations, and centrifuging to obtain a second mixture;

[0013] (3) mixing n-butanol, dimethylbenzene and an epoxy resin with the second mixture uniformly, and standing to obtain the G-clay modified epoxy resin.

[0014] The embodiment of the present application also provides a flexible curing agent, which is obtained by pre-polymerization modification of a polyether amine curing agent with a flexible side chain epoxy resin.

[0015] The embodiment of the present application also provides a preparation method of the flexible curing agent, which comprises:

[0016] The flexible curing agent is obtained by adding a cashew phenol-based epoxy resin with a flexible side chain to a stirring state polyether amine curing agent dropwise at 48-52℃ and reacting for 24-48h.

[0017] The embodiment of the present application also provides a high crack following epoxy coating for concrete, which comprises an A component and a B component.

[0018] The A component comprises the G-clay modified epoxy resin of claim 1, polydopamine, a polymer elastomer, a wet dispersing agent, a grafting coupling agent, an anti-settling agent, a pigment and filler, butanol and dimethylbenzene; and the B component comprises the flexible curing agent of claim 3, butanol and dimethylbenzene.

[0019] The application also provides a preparation method of the high-crack-following epoxy coating for concrete.

[0020] The G-clay modified epoxy resin, polydopamine, polymer elastomer, wet dispersant, grafting coupling agent, anti-settling agent, pigment and filler, butanol and dimethylbenzene are uniformly mixed to form a component A;

[0021] The flexible curing agent, butanol and dimethylbenzene are uniformly mixed to form a component B;

[0022] The component A and the component B are uniformly mixed to obtain the high-crack-following epoxy coating for concrete.

[0023] In addition, the application also provides a high-crack-following epoxy coating for concrete, which is formed by curing the high-crack-following epoxy coating.

[0024] The application also provides a preparation method of the high-crack-following epoxy coating for concrete, which comprises the following steps:

[0025] The high-crack-following epoxy coating for concrete is coated on the surface of a concrete base material, and is cured to form the high-crack-following epoxy coating for concrete.

[0026] The application also provides a use of the high-crack-following epoxy coating for concrete or the high-crack-following epoxy coating for concrete in the field of concrete structure engineering under C5 severe environment.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The coating production process provided by the application is consistent with the common coating production process, and does not require additional equipment and personnel, and the price is equivalent to that of the common epoxy coating, but the high-crack-following epoxy coating has excellent high-crack-following property, and the adhesion of the coating on the standard concrete base material is not less than 6 MPa, while the adhesion in the technical conditions for the surface coating of the concrete bridge structure in the JT / T695-2007 concrete bridge structure surface coating corrosion prevention is not less than 1.0 MPa in the weak and moderate corrosion environment, and not less than 1.5 MPa in the high corrosion environment, and the initial value reaches 4-6 times of the standard value. DETAILED DESCRIPTION

[0029] In view of the defects of the prior art, the application has been proposed by the inventors of the application through long-term research and a large number of practices, and the technical solution of the application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by the person skilled in the art without creative labor are within the protection scope of the application.

[0030] As an aspect of the present application, it relates to a G-clay modified epoxy resin and a flexible curing agent and a preparation method thereof.

[0031] Specifically, the G-clay modified epoxy resin is prepared by ion exchange reaction of a compound with both primary amine group and quaternary ammonium salt cation with nano-clay to obtain reactive G-clay, and then uniformly dispersing the G-clay into epoxy resin.

[0032] In one aspect, the present application provides a preparation method of the G-clay modified epoxy resin, which comprises:

[0033] (1) mixing solvent and nano-clay and stirring uniformly to form a first mixture;

[0034] (2) adding a compound with both primary amine group and quaternary ammonium salt cation into the upper suspension of the first mixture to perform ion exchange reaction of nano-clay with the compound with both primary amine group and quaternary ammonium salt cation, and centrifuging to obtain a second mixture;

[0035] (3) mixing n-butanol, dimethylbenzene and epoxy resin with the second mixture uniformly, and standing to obtain the G-clay modified epoxy resin.

[0036] Further, the stirring time in step (1) is 4-8h, the stirring speed is 3000-5000r / min, and the standing time is 24-48h.

[0037] Further, the step (2) is performed under protective gas atmosphere, the stirring temperature is 40-60℃, the stirring time is 4-8h, and the stirring speed is 1000-3000r / min.

[0038] In some specific embodiments, the preparation method of the G-clay modified epoxy resin comprises:

[0039] (1) mixing solvent and nano-clay and stirring uniformly to form a first mixture, and then standing at room temperature for 24-48h;

[0040] (2) adding a compound with both primary amine group and quaternary ammonium salt cation into the upper suspension of the first mixture, stirring at 40-60℃ under nitrogen atmosphere for 4-8h to perform ion exchange reaction of nano-clay with the compound with both primary amine group and quaternary ammonium salt cation, and centrifuging to obtain a second mixture;

[0041] (3) mixing n-butanol, dimethylbenzene and epoxy resin with the second mixture uniformly, and standing to obtain the G-clay modified epoxy resin.

[0042] In some preferred embodiments, the step (3) specifically comprises: stirring the mixture of n-butanol, dimethylbenzene and epoxy resin in a stirring container at a rotating speed of 1000-3000 r / min, heating the water bath to 78-82℃ and continuing to stir at a rotating speed of 3000-5000 r / min, then dropping the second mixture into the stirring container at a speed of 5-15 drops / min, then adjusting the rotating speed to 1000-3000 r / min and keeping the water bath at a constant temperature for 24-48 h, and standing to obtain the G-clay modified epoxy resin.

[0043] Further, the solvent is a mixture of one or more of acetone, benzene, chlorobenzene, etc.

[0044] Further, the compound with both primary amine group and quaternary ammonium salt cation includes acetylhydrazine trimethyl ammonium chloride.

[0045] Further, the epoxy resin includes bisphenol A epoxy resin, and is not limited thereto.

[0046] Preferably, the epoxy resin includes E51 epoxy resin, and is not limited thereto.

[0047] Further, the nanoclay is nanomontmorillonite clay with a layered structure.

[0048] Preferably, the nanoclay can be DK or DK2 nanomontmorillonite clay of Zhejiang Fenghong New Material Co., Ltd.

[0049] Further, the weight ratio of the solvent to the nanoclay in step (1) is just enough to soak the nanoclay without obvious overflow.

[0050] Further, in step (2), acetylhydrazine trimethyl ammonium chloride is added to the upper suspension of the first mixture, and the ion exchange reaction between the nanoclay and acetylhydrazine trimethyl ammonium chloride is completed under continuous stirring at 40-60℃ in a nitrogen atmosphere for 4-8 hours to form white precipitates. The above precipitates are centrifuged at 5000-10000 rpm for 6-12 min to obtain clay slurry, and the clay slurry is washed with anhydrous ethanol and then centrifuged. The washing-centrifuging step is repeated for 5-6 times until no free acetylhydrazine trimethyl ammonium chloride is detected, and the obtained slurry is the second mixture.

[0051] Further, the mass ratio of the upper suspension of the first mixture to the compound with both primary amine group and quaternary ammonium salt cation is 70-90:30-10.

[0052] Further, the mass ratio of the second mixture to the epoxy resin is 10-30:90-70.

[0053] Further, the mass ratio of the n-butanol, xylene and epoxy resin is 20-40:40-60:400-600.

[0054] In some specific embodiments, the flexible curing agent is obtained by pre-polymerization modification of a polyether amine curing agent with a flexible side chain epoxy resin.

[0055] In some specific embodiments, the preparation method of the flexible curing agent comprises:

[0056] The flexible curing agent is obtained by adding the cashew phenol-based epoxy resin with flexible side chains to the stirring polyether amine curing agent at 48-52°C dropwise and reacting for 24-48h.

[0057] Further, the stirring speed of the polyether amine curing agent is 2000-4000r / min.

[0058] Further, the mass ratio of the polyether amine curing agent and the cashew phenol-based epoxy resin with flexible side chains is 10-20:1.

[0059] Further, the preparation method comprises: uniformly dropping the cashew phenol-based epoxy resin with flexible side chains into the stirring polyether amine curing agent at a speed of 5-15 drops / min.

[0060] Further, the cashew phenol-based epoxy resin with flexible side chains can be any one of or a combination of more than two of Kardie NC-514 / NC-514S / LITE514SE or NC-547 polyether amine, and is not limited thereto.

[0061] Further, the polyether amine curing agent can be any one of or a combination of more than two of American Huntsman D230, D-2000, D-400, D-4000, and is not limited thereto.

[0062] As an aspect of the technical solution of the present application, a high crack following epoxy coating comprises component A and component B.

[0063] The component A comprises G-clay modified epoxy resin, polydopamine, polymer elastomer, wet dispersant, grafting coupling agent, anti-settling agent, pigment and filler, butanol and xylene; the component B comprises flexible curing agent, butanol and xylene.

[0064] In some specific embodiments, the component A comprises the following components in parts by weight: G-clay modified epoxy resin 30-60 parts, polydopamine 0.1-0.9 parts, polymer elastomer 1-7 parts, wet dispersant 0.5-2 parts, grafting coupling agent 0.5-3 parts, anti-settling agent 0.5-3 parts, pigment and filler 12-40 parts, butanol 3-9 parts and xylene 5-23 parts.

[0065] In some specific embodiments, the B component comprises the following components by weight parts: flexible curing agent 50-90 parts, butanol 5-15 parts, and xylene 5-35 parts.

[0066] In some specific embodiments, the mass ratio of the A component to the B component is 9-1:1.

[0067] Further, the NDJ-4 rotational viscosity of the A component is 1.0-6.0 Pa.S.

[0068] Preferably, the NDJ-4 rotational viscosity of the A component is 1.5-3.0 Pa.S.

[0069] Further, the Zahn-4 cup viscosity of the B component is 30-120 s.

[0070] Preferably, the Zahn-4 cup viscosity of the B component is 40-70 s.

[0071] Further, the G-clay modified epoxy resin is obtained by ion exchange reaction of acetylhydrazine trimethylammonium chloride, which has both primary amine groups and quaternary ammonium salt cations, with nano-clay, to obtain a G-clay with reactivity, and the clay interlayer spacing is also expanded, and then the G-clay is uniformly dispersed into the epoxy resin by the "clay slurry compounding method" to obtain the G-clay modified epoxy resin, and the organic-inorganic hybrid effect increases the toughness and mechanical strength of the resin.

[0072] Further, the polydopamine (PDA) is a kind of catechol natural substance, and the surface contains many functional groups (hydroxyl, amino, catechol groups, etc.), which is formed by the oxidation self-polymerization of dopamine (DA) under alkaline conditions. PDA has strong adhesion and can adhere to the surface of most organic or inorganic materials. Through the high adhesion brought by the many functional groups (hydroxyl, amino, catechol groups, etc.) on the surface of dopamine and the grafting and penetration function brought by the coupling agent, the compatibility of the core-shell structure polymer elastomer and other pigments and fillers with the modified epoxy resin is synergistically enhanced.

[0073] Further, the polydopamine can be produced by Xi'an Qiyue Biological Technology Co., Ltd. or Xi'an Ruixi Biological Technology Co., Ltd.

[0074] Further, the flexible curing agent uses cashew phenol-based epoxy resin with flexible side chain as modifier to pre-polymerize and modify the polyether amine curing agent, to obtain a flexible curing agent with flexible side chain, and then mix according to the formulation process to prepare the B component. The cashew phenol-based epoxy resin with flexible long chain is used as a modifier to pre-polymerize and modify the polyether amine curing agent, to obtain a flexible curing agent with flexible long chain. And the auxiliary agent, solvent are mixed according to the formulation process to prepare the B component which has the effects of flexibility, moisture curing and low temperature curing.

[0075] In some specific embodiments, the core-shell structure polymer elastomer of the polymer elastomer multilayer structure is prepared by using polydopamine to manufacture reactive active sites.

[0076] Further, the polymer elastomer can be American Polyone / Polychem 180DU45 foaming microspheres, American Kraton Versaflex CL2250 thermoplastic elastomer, American Polyone PF9512, MD6666, MD6700, MD6741, MD6748.

[0077] In some specific embodiments, the color filler includes any one or a combination of two or more of titanium dioxide, carbon black, zinc phosphate, barium sulfate, mica powder, red iron oxide, talc powder, feldspar powder, and silica powder, and is not limited thereto.

[0078] In some specific embodiments, the anti-settling agent includes any one or a combination of two or more of fumed silica, organic bentonite, and polyamide wax powder, and is not limited thereto.

[0079] In some specific embodiments, the grafting coupling agent includes any one or a combination of two or more of KH560, Adherant 1051, Adherant 1121, KBM-403, and KBM-603, and is not limited thereto.

[0080] Further, the grafting coupling agent can be any one of Haisi Adherant 1051 / 1121, Nanjing Shuguang Chemical KH560, and Shin-Etsu KBM-403 / KBM-603.

[0081] In some specific embodiments, the wet dispersing agent includes any one or a combination of two or more of ANTI-TERRA-U, DISPERBYK-110, Disponer 904S, Disponer 923S, RG-5150, and RG-5172, and is not limited thereto.

[0082] Further, the wetting dispersant can be any one of or a combination of more than two of BYK CHEMICAL ANTI-TERRA-U / DISPERBYK-110, HENKEL Disponer 904S / 923S, Changzhou Rongguan RG-5150 / RG-5172, and is not limited thereto.

[0083] In summary, the epoxy resin is modified by intercalation of G-clay with primary amine groups and quaternary ammonium salt cations, the polydopamine is used to manufacture reactive sites for polymer elastomer and pigment filler, and the flexible side chain epoxy resin is used to pre-polymerize and modify the polyether amine curing agent. The high crack following epoxy coating for concrete comprises A component and B component. During curing and film forming, the resin, pigment filler, and curing agent participate in cross-linking and curing reaction, and the coating is more flexible, more compact, and has better organic-inorganic interface compatibility, thus showing excellent crack following performance and salt spray resistance.

[0084] Another aspect of the embodiment of the present application provides a preparation method of a high crack following epoxy coating for concrete, which comprises the following steps:

[0085] The G-clay modified epoxy resin, polydopamine, polymer elastomer, wetting dispersant, grafting coupling agent, anti-settling agent, pigment filler, butanol, and dimethylbenzene are uniformly mixed to form the A component;

[0086] The flexible curing agent, butanol, and dimethylbenzene are uniformly mixed to form the B component;

[0087] The A component and the B component are uniformly mixed to obtain the high crack following epoxy coating for concrete.

[0088] In some specific embodiments, the G-clay modified epoxy resin, butanol, and dimethylbenzene are mixed, and then the wetting dispersant, grafting coupling agent, anti-settling agent, and pigment filler are sequentially added and mixed and ground to a qualified fineness, and then the polydopamine and polymer elastomer are added and mixed and stirred to disperse, and the viscosity of the obtained mixture is adjusted to form the A component;

[0089] The flexible curing agent, butanol, and dimethylbenzene are mixed and the viscosity of the obtained mixture is adjusted to form the B component;

[0090] The A component and the B component are mixed and subjected to aging treatment to obtain the high crack following epoxy coating for concrete.

[0091] In some specific embodiments, the G-clay modified epoxy resin, butanol, and dimethylbenzene are mixed, and then the wetting dispersant, grafting coupling agent, anti-settling agent, and pigment filler are sequentially added and mixed, and then the polydopamine and polymer elastomer are added and mixed and stirred to disperse, and the viscosity of the obtained mixture is adjusted to form the A component;

[0092] The flexible curing agent, butanol and xylene are mixed, stirred and dispersed, and the viscosity of the obtained mixture is adjusted to form the B component;

[0093] The A component and the B component are mixed in a mass ratio of 9-1:1, stirred and dispersed to prepare the high crack following epoxy coating for concrete.

[0094] Further, the stirring and dispersing speed is 500-1000 r / min, and the time is 3-5 min.

[0095] In some more specific embodiments, the preparation method of the G-clay modified epoxy resin comprises:

[0096] S1, 50-100 parts of nanoclay are added to a 2500 mL glass beaker, and the solvent is slowly added along the beaker wall until the clay is completely wetted but no solvent overflows. After adding 1500-2100 mL of anhydrous ethanol to the inner beaker, stirring is carried out at a speed of 2000-4000 r / min at room temperature for 4-8 h, and then the upper suspension is taken out for standby use after standing at room temperature for 24-48 h.

[0097] S2, 70-90 parts of the upper suspension are taken, 30-10 parts of acetylhydrazine trimethylammonium chloride are added, and stirring is continuously carried out at a speed of 1000-3000 r / min at 40-60°C under a nitrogen atmosphere for 4-8 h. The completely protonated nanoclay and acetylhydrazine trimethylammonium chloride complete the ion exchange reaction to form a white flocculent precipitate. The precipitate is centrifuged at 5000-10000 rpm for 6-12 min to obtain a slurry-like product. The slurry-like product is washed with anhydrous ethanol and then centrifuged again. AgNO3 solution is used to detect the chloride ions in the washed anhydrous ethanol. The washing-centrifuging-detecting steps are repeated until no silver chloride precipitate is detected in the washed anhydrous ethanol, and a slurry-like G-clay is obtained.

[0098] S3, 20-40 parts of n-butanol, 40-60 parts of xylene and 400-600 parts of E51 epoxy resin are added to a stirring pot, the stirring speed is maintained at 1000-3000 r / min, the water bath is set to a constant temperature of 80±2°C, the temperature is first raised to 80±2°C, and the stirring speed is adjusted to 3000-5000 r / min, then the mixture of S2 is added dropwise at a speed of 5-15 drops / min, it is noted that this is an exothermic reaction, and the temperature and viscosity changes in the stirring pot should be closely observed to prevent the viscosity from rising too fast and causing polymerization, after the addition of S2 is completed, the stirring speed is adjusted to 1000-3000 r / min, and the water bath is continuously maintained at a constant temperature for 24-48 h, and then the mixture is left to stand, and a G-clay modified epoxy resin is obtained.

[0099] Further, the preparation method comprises: uniformly dropping the cardanol-based epoxy resin with flexible side chains into the stirring polyetheramine curing agent at a speed of 5-15 drops / min.

[0100] In some specific embodiments, the preparation method of the flexible curing agent comprises:

[0101] (1) First, weigh a certain amount of polyetheramine curing agent into a flask, and continuously stir at a certain speed for 10-30 min under constant temperature of 50±2℃;

[0102] (2) Weigh another beaker with a certain amount of cardanol-based epoxy resin with flexible side chains, and drop the weighed cardanol-based epoxy resin with flexible side chains into the polyetheramine curing agent at a certain speed;

[0103] (3) Continue to stir at the same speed and reaction temperature for 24-48 h, and stand by to obtain the flexible curing agent.

[0104] Further, the polyetheramine curing agent can be any one or a combination of two or more of Huntsman 230, polyetheramine D-2000, polyetheramine D-400, and polyetheramine D-4000, and is not limited thereto.

[0105] Further, the cardanol-based epoxy resin with flexible side chains can be any one or a combination of two or more of Cardolite NC-514 / NC-514S / LITE514SE or NC-547 polyetheramine, and is not limited thereto.

[0106] Further, the mass ratio of the polyetheramine and the cardanol-based epoxy resin with flexible side chains is 10-20:1.

[0107] Further, the stirring speed of the polyetheramine curing agent is 2000-4000 r / min.

[0108] Further, the preparation method comprises: uniformly dropping the cardanol-based epoxy resin with flexible side chains into the stirring polyetheramine curing agent at a speed of 5-15 drops / min.

[0109] Further, the preparation method comprises: uniformly dropping the cardanol-based epoxy resin with flexible side chains into the stirring polyetheramine curing agent at a speed of 5-15 drops / min.

[0110] In some more specific embodiments, the preparation method of the flexible curing agent can comprise:

[0111] S1, under the constant temperature state of 50±2℃, first, 200-100 parts of polyether amine curing agent is weighed into a 1000ml flask, a magnetic stirring rod is added for stirring, the stirring rate is adjusted to 2000-4000r / min, and the stirring time is 10-30min;

[0112] S2, 10 parts of cashew phenol-based epoxy resin with flexible side chains is weighed into another 100ml beaker, and the weighed cashew phenol-based epoxy resin with flexible side chains is uniformly dropped into the polyether amine curing agent under high-speed stirring at a speed of 5-15 drops / min;

[0113] S3, under the constant temperature state of 50±2℃, the reaction is continuously carried out at a stirring speed of 2000-4000r / min for 24-48h, and then the mixture is left to stand, thereby obtaining a flexible curing agent for standby.

[0114] Another aspect of the embodiment of the present application also provides a preparation method of the high-crack-following epoxy coating for concrete.

[0115] The aforementioned high-crack-following epoxy coating for concrete is coated on the surface of a concrete base material, and is cured to form a high-crack-following epoxy coating for concrete.

[0116] In some more specific embodiments, the preparation method of the high-crack-following epoxy coating for concrete comprises:

[0117] The G-clay modified epoxy resin, butanol and dimethylbenzene are added into a mixing pot, and are dispersed at a high speed of 2000-4000r / min for 5-15min under a stirring machine, the wetting dispersant, the grafting coupling agent and the anti-settling agent are sequentially added, the same speed is maintained to continue high-speed dispersion for 10-30min, then the polydopamine and the polymer elastomer are added to continue high-speed dispersion for 10-30min, the viscosity of the obtained mixture is adjusted by dimethylbenzene, and then the mixture is filtered and packaged to obtain component A.

[0118] The flexible curing agent, butanol and dimethylbenzene are added into a mixing pot, and are dispersed at a high speed of 2000-4000r / min for 10-30min under a stirring machine, the viscosity of the obtained mixture is adjusted by dimethylbenzene, and then the mixture is filtered and packaged to obtain component B;

[0119] After the component A and the component B are uniformly mixed according to the principle of equivalent mass ratio of epoxy and active hydrogen, i.e., 9-1∶1, a coating operation is performed.

[0120] Another aspect of the embodiment of the present application also provides a protective coating formed by the aforementioned high-crack-following epoxy coating for concrete.

[0121] Further, the dry film thickness of the protective coating formed by single coating of the high crack following epoxy coating is above 100 μm, and the crack following property is not less than 0.4 mm, which can effectively avoid coating cracks caused by concrete stress cracking. Moreover, the crack following property is controllable through adjustment of the synthesis of the resin and the curing agent.

[0122] Another aspect of the embodiment of the present application further provides a high crack following epoxy coating for concrete prepared by curing the aforementioned high crack following epoxy coating for concrete.

[0123] In some specific embodiments, the A component and the B component are mixed at an epoxy value: amine value = 1:1 (molar ratio) and cured to form a film to prepare a high crack following epoxy coating with flexibility.

[0124] Further, the adhesion of the high crack following epoxy coating for concrete to the concrete substrate is not less than 6 MPa.

[0125] Further, the single pass dry film thickness of the high crack following epoxy coating for concrete is above 100 μm, and the crack following property is not less than 0.4 mm.

[0126] Further, the NDJ-4 rotary viscosity of the high crack following epoxy coating for concrete is 0.5-5.5 Pa.S, and the solid content after mixing is above 65 wt%.

[0127] The high crack following epoxy coating of the present application is flexible in matching mode, and when coated on the surface of the concrete substrate, the front matching coating is a sealer with high permeability, antibacterial and moisture curing functions, and the rear matching coating is a corresponding topcoat as needed, such as an acrylic polyurethane or fluorocarbon topcoat if weather resistance is required. If there is no direct sunlight, the coating can be applied in two passes without additional topcoat. After crosslinking and curing, the organic coating formed has the functions of anti-cracking, anti-permeation and corrosion protection for the concrete layer.

[0128] Further, the coating mode includes spraying, rolling, and brushing.

[0129] Preferably, the coating mode includes airless spraying.

[0130] In some specific embodiments, the high crack following epoxy coating is formed by mixing two components in proportion, which includes G-clay modified epoxy resin, polydopamine, polymeric elastomer, and flexible curing agent, and the content of each component is controlled.

[0131] Another aspect of the embodiment of the present application further provides the use of the aforementioned high crack following epoxy coating or high crack following epoxy coating in the field of concrete structure engineering in C5 harsh environment.

[0132] The technical solutions of the present application are further described in detail below in combination with several preferred embodiments. The embodiments are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0133] The experimental materials used in the following examples are commercially available from conventional biochemical reagent companies, unless otherwise specified.

[0134] Example 1

[0135] Preparation of G-clay modified epoxy resin

[0136] S1, 50 parts of nanoclay were added to a 2500 mL glass beaker, and acetone was slowly added along the wall of the beaker until the clay was completely wetted but there was no overflow of acetone. After adding 1500 mL of anhydrous ethanol to the beaker, stirring was carried out at a speed of 2000 r / min at room temperature for 8 h, and then the upper suspension was taken out and reserved for use after standing at room temperature for 48 h.

[0137] S2, 70 parts of the upper suspension were taken, 30 parts of acetylhydrazine trimethylammonium chloride were added, and stirring was continuously carried out at a speed of 3000 r / min at 40°C under a nitrogen atmosphere for 4 h. The completely protonated nanoclay and acetylhydrazine trimethylammonium chloride completed the ion exchange reaction to form a white flocculent precipitate. The precipitate was centrifuged at 5000 rpm for 6 min to obtain a slurry-like product, and the slurry-like product was washed with anhydrous ethanol and then centrifuged. AgNO3 solution was used to detect the chloride ions in the washed anhydrous ethanol, and the washing-centrifuging-detecting steps were repeated until no silver chloride precipitate was detected in the washed anhydrous ethanol, and a slurry-like G-clay was obtained.

[0138] S3, 20 parts of n-butanol, 60 parts of dimethylbenzene, and 400 parts of E51 epoxy resin were added to a stirring pot, the stirring speed was maintained at 1000 r / min, the water bath was set to a constant temperature of 80±2°C, the temperature was first raised to 80±2°C, and the stirring speed was adjusted to 3000 r / min, then the mixture of S2 was added dropwise at a speed of 5 drops / min, attention should be paid to the fact that this is an exothermic reaction, and the temperature and viscosity changes in the stirring pot should be closely observed to prevent the viscosity from rising too fast and causing polymerization explosion, after the addition of S2 was completed, the stirring speed was adjusted to 1000 r / min, and the water bath was continuously maintained at a constant temperature for 48 h, and then the mixture was left to stand, thereby obtaining a G-clay modified epoxy resin which was reserved for use.

[0139] Example 2

[0140] Preparation of G-clay modified epoxy resin

[0141] S1, 75 parts of nano-clay was added into a 2500 mL glass beaker, benzene was added along the beaker wall slowly until the clay was completely wetted but there was no benzene overflow. After adding 1800 mL of anhydrous ethanol into the beaker, stirring was carried out at a speed of 3000 r / min at room temperature for 6 h, and then the upper suspension was taken out after standing at room temperature for 36 h.

[0142] S2, 80 parts of the upper suspension was taken out, 20 parts of acetylhydrazine trimethylammonium chloride was added, and stirring was carried out at a speed of 2000 r / min at 50°C under nitrogen atmosphere for 6 h. The completely protonated nano-clay and acetylhydrazine trimethylammonium chloride completed ion exchange reaction to form a white flocculent precipitate. The precipitate was centrifuged at 7500 rpm for 9 min to obtain a slurry-like product, and the slurry-like product was washed with anhydrous ethanol and then centrifuged. AgNO3 solution was used to detect the chloride ion in the washed anhydrous ethanol, and the washing-centrifugation-detection steps were repeated until no silver chloride precipitate was detected in the washed anhydrous ethanol, and a slurry-like G-clay was obtained.

[0143] S3, 30 parts of n-butanol, 50 parts of dimethylbenzene, and 500 parts of E51 epoxy resin were added into a stirring pot, the stirring speed was maintained at 2000 r / min, the water bath was set to a constant temperature of 80±2°C, the temperature was first raised to 80±2°C, and the stirring speed was adjusted to 4000 r / min, then the mixture of S2 was added into the stirring pot at a speed of 10 drops / min, it was noted that this was an exothermic reaction, and the temperature and viscosity changes in the stirring pot were closely observed to prevent the viscosity from rising too fast to cause explosive polymerization, after the addition of S2 was completed, the stirring speed was adjusted to 2000 r / min and the water bath was continuously maintained at a constant temperature for 36 h, and then the product was obtained by standing.

[0144] Example 3

[0145] Preparation of G-clay modified epoxy resin

[0146] S1, 75 parts of nano-clay was added into a 2500 mL glass beaker, benzene was added along the beaker wall slowly until the clay was completely wetted but there was no benzene overflow. After adding 1800 mL of anhydrous ethanol into the beaker, stirring was carried out at a speed of 3000 r / min at room temperature for 6 h, and then the upper suspension was taken out after standing at room temperature for 36 h.

[0147] S2, take 90 parts of the upper suspension, add 10 parts of acetylhydrazine trimethylammonium chloride, continuously stir at 1000 r / min under nitrogen atmosphere at 60°C for 8 hours, complete ion exchange reaction of the completely protonated nanoclay and acetylhydrazine trimethylammonium chloride, form white flocculent precipitate. Centrifuge the precipitate at 10000 rpm for 12 min to obtain slurry product, wash the slurry product with anhydrous ethanol, then centrifuge, detect chloride ion in the washed anhydrous ethanol with AgNO3 solution, repeat the washing-centrifuging-detecting steps until no silver chloride precipitate is detected in the washed anhydrous ethanol, obtain slurry G-clay.

[0148] S3, add 40 parts of n-butanol, 40 parts of dimethylbenzene and 600 parts of E51 epoxy resin to a stirring pot, maintain stirring speed at 3000 r / min, set water bath at 80±2°C constant temperature, first heat to 80±2°C and adjust stirring speed to 5000 r / min, then drop the mixture of S2 into the stirring pot at a speed of 15 drops / min, note that this is an exothermic reaction, closely observe the temperature and viscosity changes in the stirring pot to prevent viscosity rising too fast causing explosive polymerization, after S2 is completely dropped, adjust stirring speed to 3000 r / min and continue water bath constant temperature for 24 h, stand, obtain G-clay modified epoxy resin ready for use.

[0149] Example 4

[0150] Preparation of flexible curing agent

[0151] S1, first weigh 100 parts of polyether amine curing agent into a 1000 ml flask under constant temperature at 50±2°C, add a magnetic stirring bar for stirring, adjust stirring speed to 2000 r / min, stirring time is 10 min;

[0152] S2, take another 100 ml beaker and weigh 5 parts of cashew phenol-based epoxy resin with flexible side chain, drop the weighed cashew phenol-based epoxy resin with flexible side chain into the high-speed stirring polyether amine curing agent at a speed of 15 drops / min;

[0153] S3, continuously react at 2000 r / min stirring speed under constant temperature at 50±2°C for 36 h, stand, obtain flexible curing agent ready for use.

[0154] Example 5

[0155] Preparation of flexible curing agent

[0156] S1, first weigh 200 parts of polyether amine curing agent into a 1000 ml flask under constant temperature at 50±2°C, add a magnetic stirring bar for stirring, adjust stirring speed to 3000 r / min, stirring time is 20 min;

[0157] S2, another 100ml beaker was weighed 17.5 parts of cashew phenol-based epoxy resin with flexible side chain, and the weighed cashew phenol-based epoxy resin with flexible side chain was uniformly dropped into the high-speed stirring polyetheramine curing agent at a speed of 10 drops / min;

[0158] S3, stirring at 3000r / min under constant temperature of 50±2℃ for 24h, standing, to obtain a flexible curing agent for standby.

[0159] Example 6

[0160] Preparation of flexible curing agent

[0161] S1, under the constant temperature of 50±2℃, first weigh 300 parts of polyetheramine curing agent into a 1000ml flask, add a magnetic stirrer for stirring, adjust the stirring rate to 4000r / min, and stir for 30min;

[0162] S2, another 100ml beaker was weighed 30 parts of cashew phenol-based epoxy resin with flexible side chain, and the weighed cashew phenol-based epoxy resin with flexible side chain was uniformly dropped into the high-speed stirring polyetheramine curing agent at a speed of 5 drops / min;

[0163] S3, stirring at 4000r / min under constant temperature of 50±2℃ for 48h, standing, to obtain a flexible curing agent for standby.

[0164] Example 7

[0165] Preparation of high crack following epoxy coating for concrete

[0166] The high crack following epoxy coating for concrete in this example includes A component and B component, the A component is made of the following components according to 100 parts of total weight: G-clay modified epoxy resin 30 parts, butanol 9 parts, dimethylbenzene 23 parts are added to the mixing pot and stirred at a speed of 4000r / min for 5min, then ANTI-TERRA-U wetting dispersant 0.5 parts, KH560 coupling agent 0.5 parts, fumed silica anti-settling agent 0.5 parts are added in turn, continue to stir at the same speed for 10min, then continue to add iron oxide red 9.4 parts, silicon powder 10 parts, mica powder 5 parts, zinc phosphate 5 parts, continue to stir at the same speed for 20min, grind to fineness≤60μm by sand mill, add polydopamine 0.1 parts, American Boliken / Polychem 180DU45 foaming microspheres 7 parts, continue to stir at the same speed for 20min, adjust the viscosity with dimethylbenzene to NDJ-4 rotary viscosity 1.5Pa.S, filter and package to obtain A component.

[0167] The flexible curing agent obtained in Example 4 of Preparation of Flexible Curing Agent, 90 parts, butanol 5 parts, xylene 5 parts were added into a mixing kettle, and dispersed at a high speed of 4000 r / min for 10 min under a stirrer, and the viscosity of the obtained mixture was adjusted to T-4 cup 70S with xylene, and the B component was obtained by filtration and packaging.

[0168] The A component and the B component were mixed and stirred uniformly at a mass ratio of 9:1, and a high crack following wet curing coating was obtained by coating on a substrate surface.

[0169] Example 8

[0170] Preparation of High Crack Following Epoxy Coating for Concrete

[0171] The high crack following epoxy coating for concrete in this example comprises an A component and a B component. The A component is prepared from the following components according to a total weight of 100 parts: G-clay modified epoxy resin 45 parts, butanol 6 parts, xylene 14 parts obtained in Example 2 of Preparation of G-Clay Modified Epoxy Resin were added into a mixing kettle and stirred at a speed of 3000 r / min for 10 min, then Disponer 923S wetting dispersant 1.3 parts, Adherant 1121 coupling agent 1.7 parts, and polyamide wax powder anti-settling agent 1.7 parts were added in sequence, and stirring was continued at the same speed for 20 min, then red iron oxide 14.8 parts, silicon powder 5 parts, mica powder 3 parts, and zinc phosphate 3 parts were added, and stirring was continued at the same speed for 30 min, and the mixture was ground by a sand mill to a fineness of ≤60 μm, then polydopamine 0.5 parts and American Corterra Versaflex CL2250 thermoplastic elastomer 4 parts were added, and stirring was continued at the same speed for 30 min, and the viscosity was adjusted to NDJ-4 rotary viscosity 2.3 Pa.S with xylene, and the A component was obtained by filtration and packaging.

[0172] The flexible curing agent obtained in Example 5 of Preparation of Flexible Curing Agent, 50 parts, butanol 15 parts, xylene 35 parts were added into a mixing kettle, and dispersed at a high speed of 3000 r / min for 20 min under a stirrer, and the viscosity of the obtained mixture was adjusted to T-4 cup 55S with xylene, and the B component was obtained by filtration and packaging;

[0173] The A component and the B component were mixed and stirred uniformly at a mass ratio of 4.5:1, and a high crack following wet curing coating was obtained by coating on a substrate surface.

[0174] Example 9

[0175] Preparation of High Crack Following Epoxy Coating for Concrete

[0176] The high crack following epoxy coating for concrete in this example comprises A component and B component. The A component is made of the following ingredients according to 100 parts by total weight: G-clay modified epoxy resin 60 parts, butanol 3 parts, xylene 5.1 parts, added into a mixing kettle and stirred at a speed of 2000 r / min for 15 min, then added into RG-5172 wetting dispersant 2 parts, KBM-403 coupling agent 3 parts, and organobentonite anti-settling agent 3 parts in sequence, and continued to stir at the same speed for 30 min, then added into red iron oxide 5 parts, silica powder 15 parts, mica powder 1 part, and zinc phosphate 1 part, and continued to stir at the same speed for 40 min, ground by a sand mill to a fineness of ≤60 μm, added into polydopamine 0.9 parts and American Pli MD6700 elastomer 1 part, and continued to stir at the same speed for 10 min, adjusted to a viscosity of 3.0 Pa.S by NDJ-4 rotary viscometer by xylene, filtered and packaged to obtain the A component.

[0177] The flexible curing agent 70 parts, butanol 10 parts, and xylene 20 parts obtained in the preparation example 6 of the flexible curing agent were added into a mixing kettle, dispersed at a high speed of 2000 r / min for 30 min under a stirrer, and adjusted to a viscosity of 40 S by T-4 cup by xylene, filtered and packaged to obtain the B component.

[0178] The A component and the B component were mixed uniformly according to a mass ratio of 1:1, coated on a substrate surface to form a film, and a high crack following wet curing coating was obtained.

[0179] Example 10

[0180] Preparation of the high crack following epoxy coating for concrete

[0181] The high crack following epoxy coating for concrete in this example comprises A component and B component. The A component is made of the following ingredients according to 100 parts by total weight: G-clay modified epoxy resin 60 parts, butanol 3 parts, xylene 5.1 parts, added into a mixing kettle and stirred at a speed of 2000 r / min for 15 min, then added into RG-5172 wetting dispersant 2 parts, KBM-403 coupling agent 3 parts, and organobentonite anti-settling agent 3 parts in sequence, and continued to stir at the same speed for 30 min, then added into red iron oxide 5 parts, silica powder 15 parts, mica powder 1 part, and zinc phosphate 1 part, and continued to stir at the same speed for 40 min, ground by a sand mill to a fineness of ≤60 μm, added into polydopamine 0.9 parts and American Pli MD6700 elastomer 1 part, and continued to stir at the same speed for 10 min, adjusted to a viscosity of 3.0 Pa.S by NDJ-4 rotary viscometer by xylene, filtered and packaged to obtain the A component.

[0182] The flexible curing agent obtained in Example 4 of Preparation of Flexible Curing Agent, 90 parts, butanol, 5 parts, xylene, 5 parts, were added to a mixing kettle, and dispersed at a high speed of 4000 r / min for 10 min under a stirrer, and the viscosity of the obtained mixture was adjusted to T-4 cup 70S with xylene, and the B component was obtained by filtration and packaging.

[0183] The A component and the B component were mixed and stirred uniformly at a mass ratio of 9:1, and a high crack following wet curing coating was obtained by coating on a substrate surface.

[0184] Example 11

[0185] Preparation of High Crack Following Epoxy Coating for Concrete

[0186] The high crack following epoxy coating for concrete in this example comprises an A component and a B component. The A component is prepared from the following components according to a total weight of 100 parts: G-clay modified epoxy resin obtained in Example 2 of Preparation of G-Clay Modified Epoxy Resin, 45 parts, butanol, 6 parts, xylene, 14 parts, were added to a mixing kettle and stirred at a speed of 3000 r / min for 10 min, and then Disponer 904S wetting dispersant, 1.3 parts, KBM-603 coupling agent, 1.7 parts, fumed silica anti-settling agent, 1.7 parts, were added in sequence, and stirring was continued at the same speed for 20 min, and then titanium dioxide, 14.8 parts, carbon black, 5 parts, barium sulfate, 3 parts, feldspar powder, 3 parts, were added, and stirring was continued at the same speed for 30 min, and then the mixture was ground by a sand mill to a fineness of ≤60 μm, and then polydopamine, 0.5 parts, and American Boriken / Polychem 180DU45 foaming microspheres, 4 parts, were added, and stirring was continued at the same speed for 30 min, and then the viscosity was adjusted to NDJ-4 rotary viscosity 2.5 Pa.S with xylene, and the A component was obtained by filtration and packaging.

[0187] The flexible curing agent obtained in Example 5 of Preparation of Flexible Curing Agent, 50 parts, butanol, 15 parts, xylene, 35 parts, were added to a mixing kettle, and dispersed at a high speed of 3000 r / min for 20 min under a stirrer, and the viscosity of the obtained mixture was adjusted to T-4 cup 55S with xylene, and the B component was obtained by filtration and packaging;

[0188] The A component and the B component were mixed and stirred uniformly at a mass ratio of 4.5:1, and a high crack following wet curing coating was obtained by coating on a substrate surface.

[0189] Example 12

[0190] Preparation of High Crack Following Epoxy Coating for Concrete

[0191] The high crack following epoxy coating for concrete in this example includes A component and B component, the A component is made of the following components according to 100 parts by total weight: G-clay modified epoxy resin 60 parts, butanol 3 parts, xylene 5.1 parts, add to the mixing pot and stir at 2000 r / min for 15 min, then add RG-5150 wetting dispersant 2 parts, KH560 coupling agent 3 parts, fumed silica anti-settling agent 3 parts in turn, continue to stir at the same speed for 30 min, then continue to add titanium dioxide 5 parts, carbon black 15 parts, barium sulfate 1 part, talc 1 part, continue to stir at the same speed for 40 min, grind to fineness ≤60 μm by sand mill, add polydopamine 0.9 parts, American Boriken / Polychem 180DU45 foaming microspheres 1 part, continue to stir at the same speed for 10 min, adjust the viscosity of the obtained mixture to NDJ-4 rotary viscosity 3.5 Pa.S with xylene, filter and package to obtain the A component.

[0192] Add flexible curing agent 70 parts, butanol 10 parts, xylene 20 parts obtained from the preparation example 6 of flexible curing agent to the mixing pot, disperse at high speed under the stirrer for 30 min, adjust the viscosity of the obtained mixture to T-4 cup 40 S with xylene, filter and package to obtain the B component;

[0193] Mix the A component and the B component uniformly according to the mass ratio 1:1, coat on the surface of the substrate to form a film to obtain the high crack following wet curing coating.

[0194] Comparative example 1

[0195] High crack following epoxy coating for concrete

[0196] The same formula and preparation method are used in this comparative example 1 and example 7, the difference is that E51 epoxy resin is used to replace G-clay modified epoxy resin in the A component, and silicon powder is used to replace elastomer.

[0197] Comparative example 2

[0198] High crack following epoxy coating for concrete

[0199] The same formula and preparation method are used in this comparative example 2 and example 8, the difference is that xylene is used to replace polydopamine in the A component, and D230 polyether amine curing agent is used to replace flexible curing agent in the B component.

[0200] Comparative example 3

[0201] High crack following epoxy coating for concrete

[0202] The same formula and preparation method are used in this comparative example 3 and example 9, the difference is that 651 polyamide curing agent is used to replace flexible curing agent in the B component.

[0203] Test experiment:

[0204] According to the test item, the corresponding test substrate is selected, the drying time, salt spray resistance, acid resistance, and alkali resistance use Q235 steel plate, and the other items use concrete test pieces. Each sample is coated once, and the test uses air spraying, with a dry film thickness of (100±10) μm. According to the concrete structure durability design standard, the concrete test piece is used in the marine chloride environment, with a severe action level, and the strength grade of the concrete is C45. The test results are shown in Table 1:

[0205] Table 1 Performance test results of the coatings of Examples 7-12 and Comparative Examples 1-3

[0206]

[0207]

[0208] As can be seen from the comparison of Examples 7-12 and Comparative Examples 1-3, the selection of the epoxy resin, the curing agent, the polydopamine, and the elastomer plays a very key role in the performance of the product. The surface treatment and the ratio of the resin, the curing agent, and the filler determine the crosslinking density of the coating and the corrosion resistance.

[0209] In addition, the inventors of the present case also refer to the aforementioned examples, and conduct tests using other raw materials, process operations, and process conditions described in the present specification, and all obtain relatively ideal results.

[0210] It should be understood that the technical solutions of the present application are not limited to the above specific implementation cases, and any technical modification made according to the technical solutions of the present application without departing from the purpose of the present application and the scope protected by the claims falls within the protection scope of the present application.

Claims

1. A high crack following epoxy coating for concrete, characterized in that: Comprising component A and component B, wherein the mass ratio of component A to component B is 9-1:1; The component A comprises, by weight, 30-60 parts of G-clay modified epoxy resin, 0.1-0.9 parts of polydopamine, 1-7 parts of polymer elastomer, 0.5-2 parts of wetting and dispersing agent, 0.5-3 parts of graft coupling agent, 0.5-3 parts of anti-settling agent, 12-40 parts of pigment and filler, 3-9 parts of butanol and 5-23 parts of xylene; The B component includes 50-90 parts of a flexible curing agent, 5-15 parts of butanol and 5-35 parts of xylene, calculated by weight; The G-clay modified epoxy resin is prepared by subjecting nanoclay to an ion exchange reaction with trimethylammonium chloride of acetylhydrazine to obtain reactive G-clay, which is then uniformly dispersed in the epoxy resin. The flexible curing agent is obtained by pre-polymerizing and modifying a polyetheramine curing agent with a cardanol-based epoxy resin having a flexible side chain; The polymer elastomer is a multi-layer core-shell polymer elastomer.

2. The high crack-following epoxy coating for concrete according to claim 1, characterized in that: The NDJ-4 rotational viscosity of the A component is 1.0-6.0 Pa.S; the Tu-4 cup viscosity of the B component is 30-120S.

3. The high crack-following epoxy coating for concrete according to claim 2, characterized in that: The NDJ-4 rotational viscosity of the A component is 1.5-3.0 Pa.S; the Tu-4 cup viscosity of the B component is 40-70S.

4. The high crack-following epoxy coating for concrete according to claim 1, characterized in that: The wetting and dispersing agent includes any one of ANTI-TERRA-U, DISPERBYK-110, Disponer 904S, Disponer 923S, RG-5150, and RG-5172, or a combination of two or more thereof.

5. The high crack-following epoxy coating for concrete according to claim 1, characterized in that: The graft coupling agent includes any one of KH560, Adherant 1051, Adherant 1121, KBM-403, and KBM-603, or a combination of two or more thereof.

6. The high crack-following epoxy coating for concrete according to claim 1, characterized in that: The anti-settling agent includes any one of fumed silica, organic bentonite, and polyamide wax powder, or a combination of two or more thereof.

7. The high crack-following epoxy coating for concrete according to claim 1, characterized in that: The pigments and fillers include any one or a combination of two or more of titanium dioxide, carbon black, zinc phosphate, barium sulfate, mica powder, red iron oxide, talcum powder, feldspar powder, and silica powder.

8. The high crack following epoxy coating for concrete according to claim 1, characterized in that: The preparation method of the G-clay modified epoxy resin comprises: (1) mixing the solvent and the nanoclay and stirring them uniformly to form a first mixture; (2) adding acetylhydrazine trimethylammonium chloride to the upper suspension of the first mixture, causing the nanoclay to undergo an ion exchange reaction with the acetylhydrazine trimethylammonium chloride, and centrifuging to obtain a second mixture; (3) Evenly mix n-butanol, xylene and epoxy resin with the second mixture and let it stand to prepare G-clay modified epoxy resin.

9. The high crack following epoxy coating for concrete according to claim 8, characterized in that: In the step (1), the stirring time is 4-8 hours, the stirring speed is 3000-5000 r / min, and the standing time is 24-48 hours.

10. The high crack-following epoxy coating for concrete according to claim 8, characterized in that: The step (2) is carried out under a protective gas atmosphere, the stirring temperature is 40-60° C., the stirring time is 4-8 h, and the stirring speed is 1000-3000 r / min.

11. The high crack-following epoxy coating for concrete according to claim 8, characterized in that: The step (3) specifically comprises: stirring the mixture of n-butanol, xylene and epoxy resin in a stirring container at a speed of 1000-3000 r / min, heating to 78-82°C and continuing stirring at a speed of 3000-5000 r / min, then dripping the second mixture into the stirring container at a rate of 5-15 drops / min, then adjusting the speed to 1000-3000 r / min and maintaining the temperature for 24-48 hours, and letting it stand to obtain G-clay modified epoxy resin.

12. The high crack-following epoxy coating for concrete according to claim 8, characterized in that: The solvent includes any one of acetone, benzene, and chlorobenzene, or a combination of two or more thereof; And / or, the nanoclay comprises nano-montmorillonite having a layered structure; and / or, the epoxy resin comprises bisphenol A epoxy resin; and / or, the mass ratio of the upper suspension of the first mixture to acetylhydrazine trimethylammonium chloride is 70-90:10-30; And / or, the mass ratio of the second mixture to the epoxy resin is 10-30: 90-70; And / or, the mass ratio of n-butanol, xylene and epoxy resin is 20-40:40-60:400-600.

13. The high crack-following epoxy coating for concrete according to claim 1, characterized in that: The preparation method of the flexible curing agent comprises: adding a cardanol-based epoxy resin with a flexible side chain to a stirred polyetheramine curing agent at 48-52° C., and reacting for 24-48 hours to obtain the flexible curing agent.

14. The high crack-following epoxy coating for concrete according to claim 13, characterized in that: The stirring rate of the polyetheramine curing agent is 2000-4000r / min; And / or, the mass ratio of the polyetheramine curing agent to the cardanol-based epoxy resin with a flexible side chain is 10-20:1; and / or, uniformly dropping a cardanol-based epoxy resin with a flexible side chain into a stirred polyetheramine curing agent at a rate of 5-15 drops / min; and / or, continuing the reaction at 23-27° C. for 24-48 hours at a stirring speed of 2000-4000 r / min.

15. The method for preparing the high crack-following epoxy coating for concrete according to any one of claims 1 to 14, characterized in that include: G-clay modified epoxy resin, polydopamine, polymer elastomer, wetting and dispersing agent, graft coupling agent, anti-settling agent, pigment and filler, butanol and xylene are uniformly mixed according to weight parts to form component A; The flexible curing agent, butanol and xylene are uniformly mixed according to parts by weight to form component B; The component A and the component B are evenly mixed in a mass ratio of 9-1:1 to prepare the high crack-following epoxy coating for concrete.

16. The preparation method according to claim 15, characterized in that Specifically include: G-clay modified epoxy resin, butanol and xylene are mixed, and then a wetting dispersant, a graft coupling agent, an anti-settling agent, and a pigment and filler are added in sequence and mixed, and then polydopamine and a polymer elastomer are added, mixed, stirred and dispersed, and the viscosity of the obtained mixture is adjusted to form the A component; Mixing the flexible curing agent, butanol and xylene, stirring and dispersing the mixture, and adjusting the viscosity of the mixture to form the B component; The component A and the component B are mixed in a mass ratio of 9-1:1 and then stirred and dispersed to prepare the high crack-following epoxy coating for concrete.

17. The preparation method according to claim 16, characterized in that The stirring and dispersing is performed at a rotation speed of 500-1000 r / min and a time of 3-5 min.

18. A high crack-following epoxy coating for concrete, characterized in that: The concrete crack-following epoxy coating according to any one of claims 1 to 14 is cured.

19. The high crack-following epoxy coating for concrete according to claim 18, characterized in that: The adhesion of the high crack following epoxy coating for concrete on the concrete substrate is not less than 5 MPa.

20. The high crack-following epoxy coating for concrete according to claim 18, characterized in that: The dry film thickness of a single coat of the high crack-following epoxy coating for concrete is above 100 μm, and the crack-following performance is not less than 0.4 mm.

21. The high crack-following epoxy coating for concrete according to claim 18, characterized in that: The NDJ-4 rotational viscosity of the high crack following epoxy coating for concrete is 0.5-5.5 Pa.S, and the solid content after mixing is above 65wt%.

22. The method for preparing a high crack-following epoxy coating for concrete according to any one of claims 18 to 21, characterized in that: include: The high crack following epoxy paint for concrete according to any one of claims 1 to 14 is applied to the surface of a concrete substrate and cured to form a high crack following epoxy coating for concrete.

23. The method for preparing a high crack-following epoxy coating for concrete according to claim 22, characterized in that: The coating method includes any one of spraying, roller coating and brushing.

24. The preparation method according to claim 23, characterized in that The coating method adopts airless spraying method.

25. Use of the high crack-following epoxy paint for concrete according to any one of claims 1 to 14 or the high crack-following epoxy coating for concrete according to any one of claims 18 to 21 in the field of concrete structure engineering under C5 severe environment.

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