Modified single-component polyurea waterproof paint, preparation method and application thereof, and hydraulic concrete protective coating structure

Abstract

The invention provides a modified single-component polyurea waterproof coating as well as a preparation method and application thereof and a hydraulic concrete protective coating structure, and relates to the technical field of hydraulic concrete protection. The modified single-component polyurea waterproof coating provided by the invention is prepared from the following raw materials by mass: polytetrahydrofuran polyol, polyether triol, fluorine-containing polyether polyol, FEVE type fluorocarbon resin, organic silicon polyether glycol, a water repellent agent, isocyanate, a defoaming agent, a diluent, a dispersing agent, a catalyst, a latent curing agent, a coupling agent, a water removal agent, a pigment filler, a thixotropic agent and a plasticizer. The modified single-component polyurea waterproof coating has excellent comprehensive mechanical properties, anti-icing adhesion performance and ice pulling resistance, and the problem of freezing injury is thoroughly solved; the surface roughness is low, the hydrophobicity is high, and resistance and roughness are reduced; the water resistance is high; the coating is high in adhesive force. The modified single-component polyurea waterproof coating is applied to cold region hydraulic concrete anti-freezing damage protection engineering, and the long-term operation protection performance is good.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic concrete protection, and in particular to a modified one-component polyurea waterproof coating, a preparation method and an application thereof, and a hydraulic concrete protection coating structure. Background Art

[0002] Due to the influence of special climate, hydrogeological conditions, construction, operation conditions and other factors in cold regions, the hydraulic concrete panels of existing or under-construction water conservancy projects in cold regions face problems such as concrete cracking, steel bar corrosion, dissolution, chemical erosion, alkali-aggregate reaction damage, mildew and other diseases, as well as freeze-thaw cycle damage, ice heaving, ice pushing, ice collision and other freeze damage problems of concrete during operation, which seriously threaten the operation safety of hydraulic concrete and shorten the service life. In hydraulic structures in cold regions, in order to prevent the hazards of ice heaving, ice collision and ice pushing, manual de-icing operations are commonly used, which cost a lot and cause certain damage to the hydraulic concrete panels at the same time. To improve the durability of hydraulic concrete, especially the durability of concrete in key parts of key projects in cold regions, in addition to improving and improving the quality of the concrete itself and the construction technology according to the environmental characteristics, applying a flexible protective coating on the concrete surface is the simplest, most convenient and most effective method.

[0003] Polyurea waterproof coating is a commonly used flexible protective coating for hydraulic concrete at present. And because one-component polyurea waterproof coating is superior to two-component polyurea waterproof coating in terms of weather resistance, expansion joint / crack sealing, adhesion, resistance to water flow velocity erosion speed, etc., it is often used as a frost damage protection material for hydraulic concrete. Although the existing one-component polyurea protective coating can isolate the entry of water and harmful ions and avoid the influence of freeze-thaw damage and chemical erosion of hydraulic concrete, there are still the following problems: (1) Insufficient water resistance, swelling, blistering and peeling problems occur after long-term soaking in water, and the protective performance is poor after long-term operation; (2) High adhesion to ice, the problem of ice layer adhesion has not been completely solved, it is difficult to avoid the influence of ice heaving, and under the influence of ice pulling force, the polyurea coating is easily damaged by ice pulling, and the freeze damage problem has not been completely solved; (3) The surface roughness is relatively high, and the contact angle with water is low. According to the test of polyurea samples from multiple manufacturers in the laboratory, the surface roughness is generally about 0.4μm, the roughness coefficient is high, the test result of the contact angle of water is about 73°, the adhesion area with ice is large, and once the ice layer adheres to the coating, it is not easy to peel off, the anti-ice adhesion is poor, which is not only not conducive to anti-ice heaving, but also the adhesion of other sundries will increase the water flow resistance and reduce the flow capacity of the water conveyance structure.

[0004] How to endow one-component polyurea waterproof coating with high water resistance, anti-ice adhesion and low surface roughness on the basis of meeting the standard performance, so as to improve the durability of one-component polyurea waterproof coating in the frost damage protection project of hydraulic concrete in cold regions, is a challenging technical problem that needs to be solved urgently. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a modified one-component polyurea waterproof coating, its preparation method, application, and a hydraulic concrete protection coating structure. The modified one-component polyurea waterproof coating provided by the present invention has excellent water resistance, ice adhesion prevention, and low surface roughness while maintaining the comprehensive mechanical properties of the one-component polyurea waterproof coating, and has good durability when applied to the anti-freezing protection project of hydraulic concrete in cold regions.

[0006] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] The present invention provides a modified one-component polyurea waterproof coating, which comprises the following preparation raw materials in mass percentage:

[0008] Polytetrahydrofuran polyol 20 - 35%, polyether triol 2.0 - 4.4%, fluorinated polyether polyol 2.2 - 4.0%, FEVE type fluorocarbon resin 1.5 - 3.3%, organosilicon polyether diol 1.1 - 1.5%, water repellent 0.3 - 1.1%, isocyanate 15.5 - 21.1%, defoaming agent 0.2 - 0.5%, diluent 10.0 - 12.0%, dispersant 0.2 - 0.3%, catalyst 0.1 - 0.3%, latent curing agent 1.0 - 3.0%, coupling agent 0.03 - 0.05%, water remover 0.3 - 0.8%, pigment and filler 20.0 - 35.0%, thixotropic agent 1.0 - 3.0%, plasticizer 5.0 - 8.0%; the latent curing agent is an imine type latent curing agent and / or an oxazolidine type latent curing agent.

[0009] Preferably, the polytetrahydrofuran polyol comprises PTMEG2000 and PTMEG1000, and the mass ratio of PTMEG2000 to PTMEG1000 is 1.3:1 - 2.5:1; the polyether triol is MN - 3050D; the fluorinated polyether polyol is perfluoropolyether diol; the organosilicon polyether diol is a hydroxyl-terminated polysiloxane.

[0010] Preferably, the average number average molecular weight of the FEVE type fluorocarbon resin is 2000 - 4000, and the fluorine content is more than 3 wt%; the water repellent is a polysiloxane solution containing amino groups; the mass ratio of the FEVE type fluorocarbon resin to the water repellent is 3:1 - 5:1.

[0011] Preferably, the diluent comprises a first diluent and a second diluent, the first diluent is an aromatic solvent, the second diluent is butyl acetate or dimethyl carbonate, and the mass ratio of the first diluent to the second diluent is 1:1 - 1:3.

[0012] Preferably, the thixotropic agent comprises hydrophobic fumed silica and liquid thixotropic agent BYK-410, and the mass ratio of the hydrophobic fumed silica to the liquid thixotropic agent BYK-410 is 1:1.

[0013] Preferably, it further comprises 0-6.0% of a chain extender, and it is not 0.

[0014] The present invention provides a preparation method of the modified one-component polyurea waterproof coating described in the above technical solution, comprising the following steps:

[0015] Mix poly(tetrahydrofuran) polyol, polyether triol, fluorinated polyether polyol, dispersant, partial defoamer, plasticizer and pigment filler to obtain a first mixture;

[0016] After dehydrating the first mixture, mix it with isocyanate for condensation reaction to obtain a second mixture;

[0017] Mix the second mixture with FEVE type fluorocarbon resin and organosilicon polyether diol to carry out the first crosslinking reaction and the second crosslinking reaction in sequence to obtain a third mixture; the second crosslinking reaction is carried out under the condition of adding a catalyst;

[0018] Mix the third mixture with a water repellent to obtain a fourth mixture;

[0019] Mix the fourth mixture with a thixotropic agent and partial diluent to obtain a fifth mixture;

[0020] Mix the fifth mixture with the remaining defoamer, the remaining diluent, latent curing agent, coupling agent and water remover to obtain the modified one-component polyurea waterproof coating.

[0021] Preferably, the temperature of the condensation reaction is 80-90°C and the time is 3-5h; the temperature of the first crosslinking reaction is 80-90°C and the time is 40-50min, and the temperature of the second crosslinking reaction is 80-90°C and the time is 1-2h.

[0022] The present invention provides the application of the modified one-component polyurea waterproof coating described in the above technical solution or the modified one-component polyurea waterproof coating prepared by the preparation method described in the above technical solution in the anti-freezing damage protection project of hydraulic concrete in cold regions.

[0023] The present invention provides a hydraulic concrete protective coating structure, comprising a polyurea primer layer, a rough sealing layer and a polyurea topcoat layer sequentially compounded on the surface of the hydraulic concrete base surface, and the polyurea topcoat layer is a coating formed by the modified one-component polyurea waterproof coating described in the above technical solution or the modified one-component polyurea waterproof coating prepared by the preparation method described in the above technical solution.

[0024] The present invention provides a modified one-component polyurea waterproof coating, which comprises the following raw materials for preparation in mass percentage: 20-35% of polytetrahydrofuran polyol, 2.0-4.4% of polyether triol, 2.2-4.0% of fluorinated polyether polyol, 1.5-3.3% of FEVE fluorocarbon resin, 1.1-1.5% of organosilicon polyether diol, 0.3%-1.1% of water repellent, 15.5-21.1% of isocyanate, 0.2-0.5% of defoamer, 10.0-12.0% of diluent, 0.2-0.3% of dispersant, 0.1-0.3% of catalyst, 1.0-3.0% of latent curing agent, 0.03-0.05% of coupling agent, 0.3-0.8% of water remover, 20.0-35.0% of pigment and filler, 1.0-3.0% of thixotropic agent, and 5.0-8.0% of plasticizer. Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention uses polytetrahydrofuran polyol and polyether triol to be compounded in a certain proportion, and controls the addition amounts of isocyanate and latent curing agent. The molecular structure of polytetrahydrofuran polyol has no side chain, strong crystallinity, and high degree of microphase separation. The molecular chain of the prepolymer formed by compounding with polyether triol is arranged relatively tightly, and has low polarity and good solvent release property. Its coating has good physical properties, can ensure both flexibility and higher strength;

[0026] The present invention grafts high-molecular-weight fluororesin (fluorinated polyether polyol and FEVE fluorocarbon resin) and silicone resin (organosilicon polyether diol) in the polyurea molecular chain segment. Through the modification of fluorine-silicone resin, the surface roughness of the coating is reduced, the hydrophobicity and durability are enhanced, the contact angle of the coating is increased, the contact with water is reduced, and an air layer on the coating surface is formed, so as to achieve the effects of anti-freezing damage and anti-ice adhesion of the hydraulic dam body, and at the same time reduce the water flow resistance and achieve the effect of resistance reduction and roughness reduction;

[0027] Through the introduction of fluororesin in the present invention, the fluororesin structure contains a large number of functional groups. A part of -OH participates in the cross-linking reaction, improves the cross-linking density, enhances the coating strength, reduces the water absorption rate, and improves the water resistance and anti-corrosion property of the coating. Another part can combine with -OH in the concrete base surface, polyurea primer or rough sealing layer to generate chemical bonds, promoting the improvement of adhesion;

[0028] The modified one-component polyurea waterproof coating provided by the present invention has excellent comprehensive mechanical properties and also has the following effects: it has anti-ice adhesion performance, resists ice pull-out, prevents ice ridges, and completely solves the freeze-thaw problems such as ice pull-out of the protective coating for hydraulic concrete; it has a low surface roughness, a large contact angle with water, high hydrophobicity, reduces resistance and roughness, and improves the flow capacity of water conveyance structures; it has high water resistance and is suitable for the protection of long-term soaking projects; the coating has strong adhesion, a lasting protection effect, and is not prone to problems such as hollowing, swelling, and large-area peeling during long-term operation. Applying the modified one-component polyurea waterproof coating provided by the present invention to the anti-freeze damage protection project of hydraulic concrete in cold regions has good long-term operation protection performance and has broad application prospects and high economic benefits in aspects such as anti-freeze damage protection of hydraulic concrete in severe cold regions and roughness reduction of water conveyance structures.

[0029] The present invention also provides a protective coating structure for hydraulic concrete, which is a coating structure of "polyurea primer + rough sealing layer + modified one-component polyurea waterproof coating". Among them, in addition to initially sealing the water vapor inside the concrete and avoiding the influence of the vapor volatilization pressure at high temperature on the surface polyurea, the polyurea primer can penetrate into the concrete interior, enhance the base surface strength, and avoid the adhesive failure form from easily showing as substrate failure; in addition to secondarily sealing the water vapor inside the concrete, the rough sealing layer has a certain roughness on its surface, which can increase the contact area of the surface polyurea coating, thereby increasing the adhesion; the modified one-component polyurea waterproof coating isolates the contact with ice, avoids the ice pull-out effect, and has functions of waterproofing, anti-corrosion, freeze-thaw resistance, ice push resistance, ice collision resistance, anti-seepage protection, and joint / crack sealing. The protective coating structure for hydraulic concrete provided by the present invention can completely solve the problems such as the decrease in adhesion during long-term operation of the protective coating, and the coating bulging, blistering, and peeling caused by the volatilization of water vapor inside the concrete. Brief Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of the protective coating structure for hydraulic concrete provided by the present invention. Detailed Embodiments

[0031] The present invention provides a modified one-component polyurea waterproof coating, which comprises the following preparation raw materials in mass percentage:

[0032] Polytetrahydrofuran polyol: 20 - 35%, polyether triol: 2.0 - 4.4%, fluorinated polyether polyol: 2.2 - 4.0%, FEVE type fluorocarbon resin: 1.5 - 3.3%, silicone polyether diol: 1.1 - 1.5%, water repellent: 0.3% - 1.1%, isocyanate: 15.5 - 21.1%, defoamer: 0.2 - 0.5%, diluent: 10.0 - 12.0%, dispersant: 0.2 - 0.3%, catalyst: 0.1 - 0.3%, latent curing agent: 1.0 - 3.0%, coupling agent: 0.03 - 0.05%, water remover: 0.3 - 0.8%, pigment and filler: 20.0 - 35.0%, thixotropic agent: 1.0 - 3.0%, plasticizer: 5.0 - 8.0%; the latent curing agent is an imine type latent curing agent and / or an oxazolidine type latent curing agent.

[0033] In the present invention, unless otherwise specified, the raw materials involved are well-known commercially available products in the art.

[0034] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 20 - 35% of polytetrahydrofuran polyol, which can be 22%, 23%, 24%, 25%, 27%, 30% or 35%. In the present invention, the polytetrahydrofuran polyol preferably includes PTMEG2000 and PTMEG1000, the molecular weights of PTMEG2000 and PTMEG1000 are 2000 and 1000 respectively, and the functionality of both is 2; the mass ratio of PTMEG2000 and PTMEG1000 is preferably 1.3:1 - 2.5:1, which can be 1.3:1, 1.5:1, 2:1 or 2.5:1. In the present invention, the polytetrahydrofuran polyol provides -OH reaction groups. This type of polyether has high crystallinity, a higher degree of microphase separation, and low polarity, making the generated prepolymer molecular chains arranged more closely, with good physical properties of the coating film and good solvent release properties. The present invention uses a certain proportion of PTMEG2000 and PTMEG1000 in compound, which can not only ensure flexibility but also ensure higher strength.

[0035] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 2.0 - 4.4% of polyether triol, which can be 2.0%, 3.0%, 4.0% or 4.4%. In the present invention, the polyether triol is preferably MN - 3050D (Shandong Bluestar Dongda Chemical Co., Ltd.), with a molecular weight of 3000 and a functionality of 3. In the present invention, the polyether triol provides -OH reaction groups, and it reacts with three -OH groups to provide the strength and high elongation rate of the coating. The present invention uses a certain proportion of polytetrahydrofuran polyol and polyether triol, which is beneficial to form a phase separation structure, improve the elongation rate, and in addition, the cost is reduced, which is conducive to popularization.

[0036] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 2.2-4.0% of fluorinated polyether polyol, which can be 2.2%, 2.5%, 3.0%, 3.5% or 4.0%. In the present invention, the fluorinated polyether polyol is preferably perfluoropolyether diol, and its structural formula is as shown in Formula I. The number average molecular weight is preferably 1000-10000. The perfluoropolyether diol is preferably YE76301 (Wuhan Kemike Biopharmaceutical Technology Co., Ltd.). In the present invention, the fluorinated polyether polyol provides -OH reactive groups and -F, improving the weather resistance and hydrophobicity of the coating.

[0037]

[0038] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 1.1-1.5% of organosilicon polyether diol, which can be 1.1%, 1.2%, 1.3%, 1.4% or 1.5%. In the present invention, the organosilicon polyether diol is preferably hydroxyl-terminated polysiloxane. In the examples of the present invention, the hydroxyl-terminated polysiloxane is purchased from Shanghai Tiger Polymer Technology Co., Ltd., with the brand name Tech-2127. In the present invention, the organosilicon polyether diol provides -OH reactive groups, -Si- and other groups for grafting reaction, improving the hydrophobic, stain-resistant and heat-resistant properties of the coating.

[0039] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 1.5-3.3% of FEVE type fluorocarbon resin, which can be 1.5%, 2.0%, 2.3%, 2.5%, 3.0% or 3.3%. In the present invention, the average number average molecular weight of the FEVE type fluorocarbon resin is preferably 2000-4000, and the fluorine content is preferably more than 3 wt%. The fluorine groups can be in the side chain, main chain, side chain and main chain. In the present invention, the FEVE type fluorocarbon resin is purchased from Wuxi Wanbo Coating Chemical Industry Co., Ltd., with the brand name WF-Q212. In the present invention, the FEVE type fluorocarbon resin provides -OH reactive groups, -F, -Cl, -COOH, ether bonds for grafting reaction, improving the weather resistance, heat resistance, hydrophobicity and corrosion resistance of the coating, promoting crosslinking and pigment and filler dispersibility. The fluorocarbon resin has good compatibility with the system.

[0040] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 0.3-1.1% of a water repellent, which can be 0.3%, 0.5%, 0.6%, 0.8%, 1.0% or 1.1%. In the present invention, the water repellent is preferably a polysiloxane solution containing amino groups. In the examples of the present invention, the water repellent is purchased from Bodi (Shanghai) Trading Co., Ltd., with the brand name Phobe 1500N. In the present invention, the water repellent further improves the hydrophobicity of the coating. In the present invention, the mass ratio of the FEVE type fluorocarbon resin to the water repellent is preferably 3:1-5:1, which can be 3:1, 3.5:1, 4:1 or 5:1. By controlling the mass ratio of the FEVE type fluorocarbon resin to the water repellent within the above range in the present invention, it is beneficial to the improvement of weather resistance and cost control, and at the same time has a certain surface hydrophobicity, increasing the contact angle.

[0041] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 15.5-21.1% of an isocyanate, which can be 16%, 18%, 19%, 20% or 21%. In the present invention, the isocyanate is preferably 4,4'-dicyclohexylmethane diisocyanate (HMDI). In the present invention, the isocyanate provides -NCO reactive groups and reacts with -OH and -NH.

[0042] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 1.0-3.0% of a latent curing agent, which can be 1.0%, 2.0% or 3.0%. In the present invention, the latent curing agent is an imine type latent curing agent and / or an oxazolidine type latent curing agent, preferably an imine type latent curing agent. In the examples of the present invention, the brand name of the imine type latent curing agent is incozol4, purchased from Shanghai Hongyi Chemical International Trade Co., Ltd. In the present invention, the latent curing agent releases -NH when encountering water and reacts with -NCO in the prepolymer to form urea bonds, extending the storage period of the one-component coating.

[0043] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention comprises 0.2-0.5% of an antifoaming agent, which can be 0.2%, 0.3%, 0.4% or 0.5%. In the present invention, the antifoaming agent is preferably a non-silicon type antifoaming agent, such as BYK-1790.

[0044] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 10.0-12.0% of a diluent, which can be 10.0%, 11.0% or 12.0%. In the present invention, the diluent preferably includes a first diluent and a second diluent. The first diluent is preferably an aromatic solvent, such as environmental solvent S-150, and the second diluent is preferably butyl acetate or dimethyl carbonate (DMC); the mass ratio of the first diluent to the second diluent is preferably 1:1-1:3, which can be 1:1, 1:2 or 1:3. In the present invention, the function of the diluent is to adjust the viscosity of the coating, facilitate the workability, and the diluent can promote low-temperature curing and shorten the curing time.

[0045] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 0.2-0.3% of a dispersant, which can be 0.2%, 0.25% or 0.3%. In the present invention, the dispersant is preferably a high molecular weight copolymer alkyl ammonium salt wetting dispersant, such as BYK-9076. In the present invention, the dispersant is used for the dispersion of powder materials and pigments.

[0046] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 0.1-0.3% of a catalyst, which can be 0.1%, 0.15%, 0.2% or 0.3%. In the present invention, the catalyst is preferably an environmental protection catalyst, organic bismuth; in the examples of the present invention, the organic bismuth is purchased from Air Products and Chemicals, Inc., USA, with the brand number DY-20. In the present invention, the catalyst is used to lower the reaction energy barrier and promote the reaction. The present invention adds a catalyst, appropriately reduces the amount of isocyanate, and introduces a solvent with fast volatility, such as butyl acetate or DMC, so that the low-temperature curing rate of the coating is fast and the coating strength is formed quickly.

[0047] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 0.03-0.05% of a coupling agent, which can be 0.03%, 0.04% or 0.05%. In the present invention, the coupling agent is preferably a silane coupling agent, such as Si-171. In the present invention, the function of the coupling agent is to promote the adhesion between the coating and the concrete substrate.

[0048] By mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 0.3-0.8% of a water scavenger, which can be 0.3%, 0.5% or 0.8%. In the present invention, the water scavenger is preferably Additive Ti. In the present invention, the function of the water scavenger is to remove trace moisture in the system and ensure the storage stability.

[0049] In terms of mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 20.0-35.0% of pigments and fillers, which can be 22.0%, 24.0%, 25.0%, 30.0% or 35.0%. In the present invention, the pigments and fillers are preferably rutile titanium dioxide, functional carbon black and nano calcium carbonate. In the embodiments of the present invention, the functional carbon black is JAZ-1 carbon black, purchased from Shandong Huibaichuan New Materials Co., Ltd.; the mass ratio of the nano calcium carbonate, titanium dioxide and functional carbon black is preferably 48:40:1. In the present invention, the pigments and fillers are used to adjust the color of the coating and increase the strength.

[0050] In terms of mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 1.0-3.0% of thixotropic agent, which can be 1.0%, 1.5%, 2.0%, 2.5% or 3.0%. In the present invention, the thixotropic agent preferably includes hydrophobic fumed silica and liquid thixotropic agent BYK-410, and the mass ratio of the hydrophobic fumed silica to the liquid thixotropic agent BYK-410 is preferably 1:1; the hydrophobic fumed silica and the liquid thixotropic agent BYK-410 act synergistically. When the total addition amount is the same, the thixotropic performance of a single thixotropic agent is weak, and more single thixotropic agent needs to be added to achieve the same effect, resulting in an increase in cost. At the same time, if the addition amount of the hydrophobic fumed silica is too much, it will increase the fineness of the coating and reduce the performance of the coating film. At the same time, the specific surface area of this thixotropic agent is large, which is not conducive to large-scale production and addition. In the present invention, the thixotropic agent provides a certain pseudothixotropy, which is convenient for the vertical construction of the coating.

[0051] In terms of mass percentage, the modified one-component polyurea waterproof coating provided by the present invention includes 5.0-8.0% of plasticizer, which can be 5.0%, 6.0%, 7.0% or 8.0%. In the present invention, the plasticizer preferably includes a first plasticizer and a second plasticizer. The first plasticizer is preferably 52# chlorinated paraffin, and the second plasticizer is preferably DIDP (diisodecyl phthalate) or DINP (diisononyl phthalate). The mass ratio of the first plasticizer to the second plasticizer is preferably 1:1. In the present invention, DIDP contains a longer carbon chain, has better high-temperature resistance and lower volatility, is not easy to migrate, and is more environmentally friendly; DINP has a slightly shorter carbon chain, can endow the material with better light resistance, heat resistance, aging resistance and electrical insulation, and the cost is lower than that of DIDP. The compounding of the two can give full play to their advantages. In the present invention, the function of the plasticizer is to increase the toughness and plasticity of the coating.

[0052] In terms of mass percentage, the modified one-component polyurea waterproof coating provided by the present invention preferably further includes a chain extender in an amount of 0 to 6.0% (and not 0), which can be 0.5%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0% or 6.0%. In the present invention, the chain extender is preferably a short-chain diol chain extender, such as FT-6270 (Suzhou Feite Brothers New Material Technology Co., Ltd.). In the present invention, the chain extender provides -OH reaction groups for chain growth.

[0053] The modified one-component polyurea waterproof coating provided by the present invention is an aliphatic polyurea, which contains a high molecular weight fluororesin and a silicone resin structure. The modified one-component polyurea waterproof coating provided by the present invention has excellent water resistance, anti-ice adhesion and low surface roughness under the condition of maintaining the comprehensive mechanical properties of the one-component polyurea waterproof coating, and has good durability when applied to the anti-freezing protection project of hydraulic concrete in cold regions.

[0054] The present invention provides a preparation method of the modified one-component polyurea waterproof coating described in the above technical solution, including the following steps:

[0055] Mix polytetrahydrofuran polyol, polyether triol, fluorinated polyether polyol, dispersant, part of the defoamer, plasticizer and pigment filler to obtain a first mixture;

[0056] After dehydrating the first mixture, mix it with isocyanate for condensation reaction to obtain a second mixture;

[0057] Mix the second mixture with FEVE-type fluorocarbon resin and organosilicon polyether diol to carry out the first cross-linking reaction and the second cross-linking reaction in sequence to obtain a third mixture; the second cross-linking reaction is carried out under the condition of adding a catalyst;

[0058] Mix the third mixture with a water repellent to obtain a fourth mixture;

[0059] Mix the fourth mixture with a thixotropic agent and part of the diluent to obtain a fifth mixture;

[0060] Mix the fifth mixture with the remaining defoamer, the remaining diluent, latent curing agent, coupling agent and water remover to obtain the modified one-component polyurea waterproof coating.

[0061] The present invention mixes polytetrahydrofuran polyol, polyether triol, fluorinated polyether polyol, dispersant, part of the defoamer, plasticizer and pigment filler to obtain a first mixture. In the present invention, the method of mixing the polytetrahydrofuran polyol, polyether triol, fluorinated polyether polyol, dispersant, part of the defoamer, plasticizer and pigment filler is preferably:

[0062] Put polytetrahydrofuran polyol, polyether triol, fluorinated polyether polyol, part of the dispersant, part of the defoamer and the plasticizer into a closed dispersion tank, disperse at a speed of 1000 - 1200 r / min for 45 min. After stirring evenly, add the pigment and filler into it. After high-speed dispersion at 1500 r / min for 1 h, then add the remaining dispersant and continue high-speed dispersion for 1 h to obtain the first mixture. In the present invention, the mass ratio of the part of the dispersant to the remaining dispersant can be 1:1.

[0063] After obtaining the first mixture, in the present invention, the first mixture is subjected to dehydration treatment and then mixed with isocyanate for condensation reaction to obtain the second mixture. In the present invention, the dehydration treatment method is preferably vacuum dehydration, the temperature is preferably 105 °C, the dehydration time is preferably 2.5 h, the dehydration treatment is preferably carried out under stirring conditions, and the stirring speed is preferably 600 - 800 r / min. The present invention preferably transfers the first mixture to a dehydration kettle for the dehydration treatment. In the present invention, after the dehydration treatment, the obtained dehydrated material is cooled to 80 °C, transferred to a reaction kettle, and the pipeline is rinsed with a diluent; the moisture content of the dehydrated material is below 0.05 wt%.

[0064] The present invention preferably adds isocyanate to the dehydrated material obtained from the dehydration treatment. The isocyanate is preferably added in three times by the method of adding while stirring, and the time interval between two adjacent additions is preferably 20 min and added up within 40 min; when adding isocyanate, the temperature of the dehydrated material is preferably 60 °C.

[0065] In the present invention, the temperature of the condensation reaction is preferably 80 - 90 °C, which can be 80, 85 or 90 °C, and the time is preferably 3 - 5 h, which can be 3, 3.5, 4 or 5 h. The time of the condensation reaction is calculated from the completion of the addition of isocyanate. During the condensation reaction, the polytetrahydrofuran polyol, polyether triol and fluorinated polyether polyol react with isocyanate to generate a urethane prepolymer containing terminal - NCO.

[0066] After obtaining the second mixture, the present invention mixes the second mixture with FEVE - type fluorocarbon resin and organosilicon polyether diol to carry out the first cross - linking reaction and the second cross - linking reaction in sequence to obtain the third mixture; the second cross - linking reaction is carried out under the condition of adding a catalyst.

[0067] In the invention, the temperature of the first crosslinking reaction is preferably 80 to 90 °C, and can be 85 °C; the time is preferably 40 to 50 min, and can be 45 min. The temperature of the second crosslinking reaction is preferably 80 to 90 °C, and can be 85 °C; the time is preferably 1 to 2 h, and can be 1.5 h. In the present invention, the fluorocarbon resin is of the FEVE type and contains -OH in its molecular structure. The organosilicon polyether diol contains 2 -OH groups, and both can crosslink with the terminal -NCO of the urethane prepolymer containing terminal -NCO formed after the above condensation reaction. Since the primary -OH in the organosilicon polyether diol has a higher reaction activity than the -OH in the fluorocarbon resin, the -OH in the organosilicon polyether diol reacts preferentially, and then under the catalysis of the catalyst, the reaction is complete.

[0068] After obtaining the third mixture, in the present invention, the third mixture is mixed with a water repellent to obtain a fourth mixture. In the present invention, the temperature of the mixing is preferably 50 to 60 °C, and can be 55 °C; the time is preferably 1 to 2 h, and can be 1, 1.5 or 2 h. When the water repellent is a polysiloxane solution containing amino groups, during the mixing, the amino groups contained in the water repellent react with the terminal -NCO in the third mixture to form urea bonds, and this reaction can prevent the water repellent from being washed away by water flow. In the present invention, a chain extender is preferably added during the mixing of the third mixture and the water repellent. When the chain extender is added, a chain extension reaction is carried out simultaneously, that is, the -OH in the chain extender further crosslinks with the -NCO in the polyurethane prepolymer to realize the chain growth process. During the chain extension reaction process, the NCO content of the product is measured until the NCO content is lower than 2.14%.

[0069] After obtaining the fourth mixture, in the present invention, the fourth mixture is mixed with a thixotropic agent and a part of the diluent to obtain a fifth mixture.

[0070] In the present invention, the method for mixing the fourth mixture with the thixotropic agent and the part of the diluent is preferably as follows:

[0071] Mix the first thixotropic agent with a part of the diluent to obtain a pre-dispersed first thixotropic agent;

[0072] Cool the fourth mixture to below 65 °C, add the pre-dispersed first thixotropic agent thereto, and disperse at a high speed for 30 min. Cool the obtained mixture to 60 °C, then add the second thixotropic agent thereto, and disperse for 30 min until it is uniform to obtain a fifth mixture.

[0073] In the present invention, the mass ratio of the first thixotropic agent to the part of the diluent is preferably 1:10. The mixing of the first thixotropic agent and the part of the diluent is preferably carried out by dispersing at a speed of 1000 r / min for 30 min.

[0074] After obtaining the fifth mixture, the present invention mixes the fifth mixture with the remaining defoamer, remaining diluent, latent curing agent, coupling agent, and water remover to obtain the modified one-component polyurea waterproof coating.

[0075] In the present invention, the mass ratio of the remaining defoamer to the above-mentioned partial defoamer can be 1:1. In the present invention, the mixing of the fifth mixture with the remaining defoamer, remaining diluent, latent curing agent, coupling agent, and water remover is preferably carried out by dispersing for 30 min at a rotation speed of 1200 r / min; after the mixing, it is also preferably to subject the obtained mixture to vacuum degassing for 30 min under -0.95 MPa, and the vacuum degassing is preferably carried out under the condition of stirring, the rotation speed of the stirring is preferably 350 r / min, and after the vacuum degassing, the material is discharged.

[0076] In the present invention, after the chain extension reaction, the final product is a prepolymer with a large molecular weight and high cross-linking degree containing -NCO. The added latent curing agent contains -NH that is blocked. The latent curing agent is deblocked when encountering water vapor, exposing the reactive -NH, which can quickly react with -NCO to generate urea bonds. This reaction is an addition polymerization reaction, in which the -N=C=O double bond of the isocyanate reacts with the active hydrogen in the amino compound to form a urea group (-NH-CO-NH-) structure.

[0077] The present invention provides the application of the modified one-component polyurea waterproof coating described in the above technical solution or the modified one-component polyurea waterproof coating prepared by the preparation method described in the above technical solution in the anti-freezing protection project of hydraulic concrete in cold regions.

[0078] The present invention provides a protective coating structure for hydraulic concrete, including a polyurea primer layer, a rough sealing layer, and a polyurea topcoat layer that are sequentially compounded on the surface of the hydraulic concrete base surface. The polyurea topcoat layer is a coating formed by the modified one-component polyurea waterproof coating described in the above technical solution or the modified one-component polyurea waterproof coating prepared by the preparation method described in the above technical solution.

[0079] The schematic diagram of the protective coating structure for hydraulic concrete provided by the present invention is as Figure 1 shown, and the following will be described in detail in conjunction with Figure 1 this.

[0080] In the present invention, the polyurea primer coat is preferably a special polyurea primer coating. The viscosity of the special polyurea primer coating is preferably 200 to 350 mPa·s. The special polyurea primer coating is preferably a penetrating two-component flexible epoxy interface agent. In the embodiments of the present invention, the special polyurea primer coating is purchased from Xinjiang Keneng New Material Technology Co., Ltd., and the product name is two-component modified epoxy interface agent. The primer coat formed by the special polyurea primer coating not only ensures good permeability, but also has good sealing and bonding properties. This primer coat belongs to a low-temperature and humid-curing type primer coat, which can be surface-dried within 10 hours at a temperature of -5°C, and the bond strength with clear water is greater than 4 MPa to meet the requirements of hydraulic concrete construction conditions. At the same time, this primer coat also has the following functions: (1) It penetrates into the concrete interior by 2 to 3 mm to initially seal the water vapor inside the concrete and improve the appearance quality of the polyurea; (2) It enhances the surface strength of the concrete, reduces the surface tension difference between the concrete and the surface layer material, and improves the compatibility; (3) It improves the bond strength between the concrete and the surface layer material to prevent peeling and hollowing. In the present invention, the thickness of the polyurea primer coat is preferably 10 to 20 μm, and it can be 10, 15 or 20 μm.

[0081] In the present invention, the rough sealing layer (intermediate coat) is preferably a coating formed by a cementitious material and a powder. The mass ratio of the cementitious material to the powder is preferably 1:4 to 5, and it can be 1:4, 1:4.5 or 1:5. In the present invention, the cementitious material is preferably a GMT new type of rapid repair and erosion-resistant material, purchased from Xinjiang Keneng New Material Technology Co., Ltd. In the present invention, the powder preferably includes inorganic pigments and fillers. The inorganic pigments preferably include titanium dioxide and functional carbon black. The functional carbon black is preferably JAZ-1 carbon black, purchased from Shandong Huibaichuan New Material Co., Ltd. The mass ratio of titanium dioxide to functional carbon black is preferably 40:1. The filler is preferably quartz sand with a mesh size of 20 to 40. The mass ratio of the filler to the inorganic pigments is preferably 3:1. The inorganic pigments are used to adjust the color of the sealing layer to gray to avoid the situation of thin coating showing the base layer and maintain the aesthetics. The filler provides a certain roughness to the sealing layer. In the present invention, the thickness of the rough sealing layer is preferably 1 to 2 mm, specifically based on completely sealing the concrete holes. In the present invention, while ensuring a certain bonding and base surface leveling effect, the rough sealing layer has a certain roughness on the surface to increase the bonding contact surface with the polyurea. The specific functions are: secondary sealing of the water vapor inside the concrete; repairing and leveling the base surface; the roughness of the intermediate coat surface improves the bonding property with the coating layer.

[0082] In the present invention, the polyurea surface coating is a coating formed by the modified one-component polyurea waterproof coating described in the above technical solution or the modified one-component polyurea waterproof coating prepared by the preparation method described in the above technical solution. In the present invention, the thickness of the polyurea surface coating is preferably 1.5 - 2 mm. In the present invention, the functions of the polyurea surface coating are as follows: isolating contact with ice, avoiding ice-pulling effect, waterproofing, anti-corrosion, freeze-thaw resistance, ice-pushing resistance, ice-collision resistance, anti-seepage protection, and joint / crack sealing.

[0083] In the present invention, the construction method of the hydraulic concrete protective coating structure is preferably as follows:

[0084] (1) Construction process

[0085] Inspection of the hydraulic concrete base surface (testing the moisture content and bond strength of the base surface) → Base surface treatment → Coating the special primer for polyurea coating → Coating the rough-sealing intermediate coat → Coating the modified polyurea surface coat (i.e., the modified one-component polyurea waterproof coating) → Coating treatment for detailed structures → Curing and acceptance.

[0086] (2) Construction method

[0087] (2.1) Inspection of the hydraulic concrete base surface: The moisture content of the base surface < 7%, and the bond strength ≥ 2.5 MPa.

[0088] (2.2) Base surface treatment: The base surface is treated and accepted before the construction of the waterproof layer. The base surface is clean, dry, firm, flat, without sanding, hollowing, sundries, floating dust, oil stains, etc. For defective base surfaces, they should be pre-treated: If the concrete erosion depth is within 2 cm, it is repaired and leveled with rough-sealing materials; if cracks greater than 0.2 mm appear on the concrete surface, the cracks need to be chemically grouted or grooved and sealed first.

[0089] (2.3) Coating the special primer for polyurea coating: Coat the special primer evenly without missing coating or accumulation. The dosage is 0.18 - 0.2 kg / m 2 , and according to the on-site temperature, the interval time is 5 h (23 °C) before coating the subsequent coating. The ambient temperature of each project is different, and the time length varies. The judgment criterion is that the primer shows a sticky state, and then the next construction can be carried out;

[0090] After the primer is coated, the subsequent polyurea coating operation should be carried out within the specified time of the primer. If the specified interval time is exceeded, the primer should be re-coated.

[0091] (2.4) Coating the rough-sealing intermediate coat: After the primer is surface-dried, the cementitious material and powder are fully mixed in accordance with the specified ratio and applied to the base surface treated with the primer to completely seal the concrete holes.

[0092] (2.5) Apply the modified polyurea topcoat: After the rough and sealed intermediate coat is surface dry, open the packaging bucket and apply the modified polyurea topcoat by manual brushing, rolling or spraying. Generally, apply it 2 - 4 times, and control the thickness of each coat at 0.5 ± 0.1 mm according to different waterproof parts and waterproof grade requirements. The following three points should be noted:

[0093] ① Check whether the packaging of the modified one-component polyurea waterproof coating is intact and whether it is within the shelf life. Open the packaging bucket and observe whether there is precipitation or stratification caused by long-term storage or long-distance bumping. When the material is unevenly distributed, it should be slowly stirred evenly in advance before use;

[0094] ② To ensure interlayer adhesion, the interval between each coat application should not exceed the maximum coating interval time: Generally, when the temperature is -10℃ to +15℃, it should not exceed 72 hours; when the temperature is 15℃ to 25℃, it should not exceed 12 hours; when the temperature is 28℃ to 35℃, it should not exceed 8 hours. If the maximum coating interval time is exceeded or the base surface has become smooth (surface is smooth), the polyurea surface needs to be sanded again, and a special primer should be applied before applying the polyurea coating;

[0095] ③ The coating thickness should be uniform, and it should be formed in one application without scraping back and forth to prevent small bubbles from appearing. The brushing method for each coat can be carried out according to the cross-cross method;

[0096] ④ When the rough and sealed intermediate coat is completely dry, a second coat of primer needs to be applied, and the polyurea topcoat should be applied when the primer is surface dry and sticky.

[0097] (2.6) Treatment and application for detailed structures: For special structural parts, the following corresponding treatments should be carried out to complete the finishing work for special parts:

[0098] ① For complex parts such as structural internal and external corners, pipe roots passing through the wall, construction joints, roof water outlets, equipment bases, etc., a strengthening layer should be set. The thickness of the strengthening layer should not be less than 1.0 mm, and the width should not be less than 100 mm;

[0099] ② The end of the waterproof layer of the parapet wall should be made up to under the coping of the parapet wall and sealed tightly with a sealing material. The coping should be waterproofed;

[0100] ③ When carrying out waterproof and thermal insulation construction on a metal base surface, the metal base should be rust-removed and the surface should be made as flat as possible before the polyurea waterproof layer construction;

[0101] ④ For places such as floor drains, pipe roots, internal and external corners, etc., a one-layer-two-coat strengthening layer treatment should be carried out with modified one-component polyurea and polyester mesh cloth. The primer should be applied before treatment, and the total thickness should not be less than 1.5 mm.

[0102] To ensure the firm and reliable lap joint between the polyurea coating and the surrounding concrete, and to prevent it from opening and lifting under the scouring of high-speed water flow, the concrete at the edge is ground into an inverted triangle, the thickness of the polyurea at the edge is greater than the designed thickness, and a smooth transition is ensured at the lap joint between the polyurea and the surrounding concrete. The polyurea coating should be within the range of the primer coating.

[0103] (2.7) Curing: Avoid rainy and snowy weather. It is not advisable to come into contact with water within 2 hours after the coating construction is completed, and external force impacts should be prevented within 24 hours.

[0104] The present invention provides a protective coating structure of "special primer for polyurea + rough sealing layer + modified one-component polyurea waterproof coating". This protective coating is not affected by the operating environment, ensures the compatibility between coatings, and guarantees long-term good adhesion.

[0105] To further illustrate the present invention, the following examples are used to describe in detail the modified one-component polyurea waterproof coating provided by the present invention, its preparation method, application, and the hydraulic concrete protective coating structure, but they should not be construed as limiting the protection scope of the present invention.

[0106] Examples 1 - 7

[0107] The raw material dosages of Examples 1 - 7 are shown in Table 1. The specific types of raw materials and the preparation steps of the modified one-component polyurea waterproof coating are as follows:

[0108] (1) Dispersion: Weigh polytetrahydrofuran polyol, polyether triol, fluorinated polyether polyol, 1 / 2 dispersant (i.e., 1 / 2 of the total mass of the dispersant), 1 / 2 defoamer (i.e., 1 / 2 of the total mass of the defoamer), and plasticizer into a closed dispersion tank, disperse at 1200 r / min for 45 min. After stirring evenly, add pigments and fillers, disperse at a high speed of 1500 r / min for 1 h, and then add the other 1 / 2 dispersant and continue to disperse at a high speed for 1 h;

[0109] Among them, the polytetrahydrofuran polyol is PTMEG2000 and PTMEG1000 (purchased from BASF), and the mass ratio is 2:1; the polyether triol is MN - 3050D, purchased from Shandong Bluestar Dongda Chemical Co., Ltd.; the fluorinated polyether polyol is perfluoropolyether diol, purchased from Wuhan Kemike Biopharmaceutical Technology Co., Ltd., with the product number YE76301; the dispersant is BYK - 9076; the defoamer is BYK - 1790; the plasticizer is 52# chlorinated paraffin and DIDP, and the mass ratio of 52# chlorinated paraffin to DIDP is 1:1; the pigments and fillers are titanium dioxide, functional carbon black (JAZ - 1 carbon black, purchased from Shandong Huibaichuan New Materials Co., Ltd.), and nano calcium carbonate. The mass ratio of the nano calcium carbonate, titanium dioxide, and functional carbon black is 48:40:1.

[0110] (2) Dehydration: Transfer the uniformly dispersed material from step (1) into a dehydration kettle, start heating and vacuum pumping, with a rotation speed of 650 r / min, heat up to 105 °C for vacuum dehydration for 2.5 h, and the water content of the obtained dehydrated material is below 0.05 wt%.

[0111] (3) Cooling: Cool the dehydrated material obtained in step (2) to 80 °C, transfer it to a reaction kettle, and rinse the pipeline with a diluent;

[0112] (4) Reaction: At a temperature of 60 °C, add HMDI to the dehydrated material obtained in step (3) (add it in three times while stirring, with a time interval of 20 min each time and finish adding within 40 min), react at 80 °C for 3.5 h; heat up to 85 °C, add fluorocarbon resin and organosilicon polyether diol, react for 45 min, add a catalyst, and continue stirring and reacting for 1.5 h; cool down to 55 °C, add a chain extender and a water repellent, and continue reacting for 1 h;

[0113] Among them, HMDI is 4,4'-dicyclohexylmethane diisocyanate; the fluorocarbon resin is FEVE resin, purchased from Wuxi Wanbo Coating Chemical Co., Ltd., with the brand WF-Q212; the organosilicon polyether diol is a hydroxyl-terminated polysiloxane, purchased from Shanghai Tiger Polymer Technology Co., Ltd., with the brand Tech-2127; the catalyst is an environmentally friendly catalyst organobismuth, purchased from Air Products Chemicals, Inc., USA, with the brand DY-20; the chain extender is FT-6270, purchased from Suzhou Feite Brothers New Material Technology Co., Ltd.; the water repellent is purchased from Bodi (Shanghai) Trading Co., Ltd., with the brand Phobe 1500N.

[0114] (5) Measuring the NCO content: After the NCO content is lower than 2.14%, cool down to below 65 °C, add a mixture of pre-dispersed hydrophobic fumed silica and part of the diluent (the mass ratio of hydrophobic fumed silica to part of the diluent is 1:10, disperse at 1000 r / min for 30 min), and disperse at high speed for 30 min; the hydrophobic fumed silica is purchased from Shanghai Zhenli Shi Network Technology Co., Ltd., with the brand CAB-O-SIL TS610; the diluent is a mixed solvent composed of solvent S150 and butyl acetate in a mass ratio of 1:1.

[0115] (6) Thixotropic treatment: Cool the mixture obtained in step (5) to 60 °C, add BYK-410, and disperse for 30 min until uniform; the hydrophobic fumed silica in step (5) and BYK-410 in step (6) together are thixotropic agents, and the mass ratio of hydrophobic fumed silica to BYK-410 is 1:1.

[0116] (7) Add the other 1 / 2 defoamer, the remaining diluent, latent curing agent, coupling agent, and water remover, with a rotation speed of 1200 r / min, and disperse for 30 min;

[0117] Among them, the latent curing agent is an imide-based latent curing agent with the brand name Incozol 4, purchased from Shanghai Hongyi Chemical International Trade Co., Ltd.; the coupling agent is the silane coupling agent Si-171; the water remover is Additive Ti, purchased from Milliken Enterprise Management (Shanghai) Co., Ltd.

[0118] (8) Vacuum defoaming: Vacuum defoaming is carried out at -0.95 MPa for 30 min, the stirring speed is 350 r / min, and then the material is discharged to obtain the modified one-component polyurea waterproof coating.

[0119] Table 1 Raw material dosages of the modified one-component polyurea waterproof coatings in Examples 1 to 7

[0120]

[0121]

[0122] Comparative Example 1

[0123] The addition of fluorinated polyether polyol, fluorocarbon resin, silicone polyether diol and water repellent is omitted, and the rest is the same as in Example 1 to obtain a one-component polyurea waterproof coating.

[0124] The one-component polyurea waterproof coatings obtained in the examples and comparative examples were subjected to performance tests. The test items and test results are shown in Table 2. In Table 2, the first 11 items and the artificial weathering reference standard are JC / T 2435-2018; the 72-hour underwater steel ball method reference standard is DL / T 5193-2021; the acid treatment is soaking in a 2 wt% sulfuric acid solution for 168 h, the alkali treatment is soaking in an alkali solution (0.1 wt% NaOH solution + saturated Ca(OH) 2 solution) for 168 h, the salt treatment is treating with a 3 wt% NaCl solution for 168 h, and the surface roughness or contact angle is measured after the above acid treatment, alkali treatment or salt treatment.

[0125] Table 2 Performance test results of the one-component polyurea waterproof coatings obtained in the examples and comparative examples

[0126]

[0127]

[0128]

[0129] Comparison of roughness reduction materials: According to DB64 / T 1777-2021 "Technical Guidelines for Roughness Reduction and Protection of Irrigation Area Water Conveyance Structures" and the roughness reduction materials on the market retrieved from the literature, tests were carried out, and the results are shown in Table 3 (the stain resistance in Table 3 was detected according to the 5.4A method in GB / T 9780-2013).

[0130] Table 3 Comparison of the performance of roughness reduction materials

[0131]

[0132] Example 8

[0133] A water conservancy concrete protective coating structure (as Figure 1 shown), including a special polyurea primer layer, a roughness sealing layer and a polyurea topcoat which are successively compounded on the surface of the water conservancy concrete base surface. The polyurea topcoat is a coating formed by the modified one-component polyurea waterproof coating prepared in Example 6. The construction method is as follows:

[0134] (1) Detection of the water conservancy concrete base surface: the moisture content of the base surface < 7%, and the bonding strength ≥ 2.5 MPa;

[0135] (2) Base surface treatment: The base surface is treated and accepted before the construction of the waterproof layer. The base surface is clean, dry, firm, flat, without sanding, without hollowing, without sundries, floating dust, oil stains, etc. For defective base surfaces, they should be treated in advance: If the concrete erosion depth is within 2 cm, use roughness sealing materials to repair and level; If cracks larger than 0.2 mm appear on the concrete surface, it is necessary to first carry out chemical grouting or grooving and sealing treatment on the cracks;

[0136] (3) Apply the special primer for polyurea coating: Apply the special polyurea primer (two-component modified epoxy interface agent, purchased from Xinjiang Kenen New Materials Technology Co., Ltd.), with a thickness of 15 μm.

[0137] (4) Apply the roughness sealing intermediate coat: After the primer surface is dry, the roughness sealing intermediate coat fully mixes the cementitious material and the powder according to the specified ratio, and applies it to the base surface treated with the primer to completely seal the concrete holes; Among them, the cementitious material is GMT new type rapid repair and erosion-resistant material (purchased from Xinjiang Kenen New Materials Technology Co., Ltd.), the powder is a mixture of inorganic pigments and fillers, the inorganic pigments are titanium dioxide and functional carbon black (the mass ratio of titanium dioxide to functional carbon black is 40:1, the functional carbon black is JAZ-1 carbon black, purchased from Shandong Huibaichuan New Materials Co., Ltd.), the filler is quartz sand with a particle size of 20 - 40 mesh, and the mass ratio of quartz sand to inorganic pigments is 3:1, and the mass ratio of the cementitious material to the powder is 1:4.5.

[0138] (5) Apply the modified polyurea topcoat: After the roughness sealing intermediate coat surface is dry, open the packaging bucket and manually brush the polyurea topcoat (the modified one-component polyurea waterproof coating prepared in Example 6), brush 4 times, and control the thickness of each brush to be 0.5 ± 0.1 mm.

[0139] (6) Treatment and painting of detailed structure: To ensure the firm and reliable lap between the polyurea coating and the surrounding concrete, and to prevent it from opening and lifting under the scouring of high-speed water flow, the concrete at the edge is ground into an inverted triangle, the thickness of the polyurea at the edge is greater than the designed thickness, and a smooth transition is ensured at the lap between the polyurea and the surrounding concrete. The polyurea coating should be within the range of the primer painting.

[0140] (7) Curing: Avoid rainy and snowy weather. It is not advisable to contact water within 2 hours after the coating construction is completed, and external force impact should be prevented within 24 hours.

[0141] Comparative Example 2

[0142] Replace the special polyurea primer coating in Example 8 with a common primer (SK-BE14 interface agent, purchased from Beijing Senjuke High Polymer Materials Co., Ltd.), and omit the rough sealing layer. The rest is the same as in Example 8.

[0143] Comparative Example 3

[0144] Omit the rough sealing layer in Example 8, and the rest is the same as in Example 8.

[0145] After curing the hydraulic concrete protective coating structures formed in Example 8 and Comparative Examples 2 - 3 for 7 days, perform performance tests. The test items and results are shown in Table 4.

[0146] Table 4 Performance test results of the hydraulic concrete protective coating structures formed in Example 8 and Comparative Examples 2 - 3

[0147]

[0148] In Table 4, the wet heat immersion cycle, freeze-thaw cycle, and high-low temperature dry heat cycle refer to the standards JC / T2435 - 2018 and DL / T5193 - 2021, and the specific conditions are as follows:

[0149] Wet heat immersion cycle:

[0150] 1) This test simulates the thermal compatibility performance between the coating material and the concrete base under the environmental conditions of sudden thunderstorm heat shock or temperature drop caused by rising water level after the hydraulic concrete itself and the painted coating are protected;

[0151] 2) The concrete specimens are 150mm×150mm×100mm, and the coating thickness is 2mm;

[0152] 3) The specimens are taken out after being placed in an oven at 70°C for 5.5 hours, and directly put into a water bath (water temperature is 20°C). After 15 minutes, they are taken out, and this is regarded as 1 cycle.

[0153] Freeze-thaw cycle:

[0154] 1) Evaluate the anti-freeze-thaw protection effect of the coating on the concrete;

[0155] 2) Concrete test blocks: 100mm×100mm×400mm

[0156] 3) Freeze-thaw conditions: Place for 1.5 h in an environment of -25°C and then for 1.5 h in an environment of 20°C, taking this as one cycle.

[0157] High and low temperature dry heat cycle:

[0158] 1) Evaluate the ability of the material to adapt to environmental temperature changes during the concrete protection process;

[0159] 2) The lowest temperature is set at -40°C and the highest temperature is set at 55°C; for the concrete specimen of 150mm×150mm×100mm, the coating is applied with a thickness of 2 mm.

[0160] 3) The heating and cooling rates are 3°C / min. Place for 153 min at -40°C and 153 min at 55°C. One cycle takes about 6 hours and 10 minutes; after 30 cycles, it is determined whether to continue.

[0161] It can be seen from the above embodiments that the modified one-component polyurea waterproof coating provided by the present invention has excellent comprehensive mechanical properties, high hydrophobicity, weather resistance, non-stickiness to ice, and low surface roughness, and can be used for the effects of anti-freezing damage, anti-disease, and roughness reduction of hydraulic concrete, and has a broader application prospect and higher economic benefit in aspects such as anti-freezing damage protection of hydraulic concrete in cold regions and roughness reduction of water conveyance buildings.

[0162] The above description is only a preferred embodiment of the present invention and does not impose any form of limitation on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A modified one-component polyurea waterproof coating, characterized in that: Including the following raw materials in percentage by weight: The invention comprises 20-35% of polytetrahydrofuran polyol, 2.0-4.4% of polyether triol, 2.2-4.0% of fluorine-containing polyether polyol, 1.5-3.3% of FEVE type fluorocarbon resin, 1.1-1.5% of organosilicon polyether diol, 0.3-1.1% of hydrophobic agent, 15.5-21.1% of isocyanate, 0.2-0.5% of defoaming agent, 10.0-12.0% of diluent, 0.2-0.3% of dispersant, 0.1-0.3% of catalyst, 1.0-3.0% of latent curing agent, 0.03-0.05% of coupling agent, 0.3-0.8% of water removing agent, 20.0-35.0% of pigment and filler, 1.0-3.0% of thixotropic agent and 5.0-8.0% of plasticizer; the latent curing agent is an imine latent curing agent and / or an oxazolidine latent curing agent.

2. The modified one-component polyurea waterproof coating according to claim 1, characterized in that: The polytetrahydrofuran polyol includes PTMEG2000 and PTMEG1000, and the mass ratio of PTMEG2000 to PTMEG1000 is 1.3:1-2.5:1; the polyether triol is MN-3050D; the fluorine-containing polyether polyol is perfluoropolyether diol; and the silicone polyether diol is hydroxyl-terminated polysiloxane.

3. The modified one-component polyurea waterproof coating according to claim 1, characterized in that: The FEVE type fluorocarbon resin has an average number average molecular weight of 2000 to 4000 and a fluorine content of more than 3 wt %; the hydrophobic agent is a polysiloxane solution containing an amino group; and the mass ratio of the FEVE type fluorocarbon resin to the hydrophobic agent is 3:1 to 5:

1.

4. The modified one-component polyurea waterproof coating according to claim 1, characterized in that: The diluent includes a first diluent and a second diluent, the first diluent is an aromatic hydrocarbon solvent, the second diluent is butyl acetate or dimethyl carbonate, and the mass ratio of the first diluent to the second diluent is 1:1 to 1:

3.

5. The modified one-component polyurea waterproof coating according to claim 1, characterized in that: The thixotropic agent includes hydrophobic fumed silica and liquid thixotropic agent BYK-410, and the mass ratio of the hydrophobic fumed silica to the liquid thixotropic agent BYK-410 is 1:

1.

6. The modified one-component polyurea waterproof coating according to claim 1, characterized in that: It also includes 0-6.0% of chain extender, and is not zero.

7. The method for preparing the modified one-component polyurea waterproof coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: Mixing polytetrahydrofuran polyol, polyether triol, fluorine-containing polyether polyol, dispersant, part of defoamer, plasticizer and pigment filler to obtain a first mixed material; Dehydrating the first mixed material, and then mixing it with isocyanate for condensation reaction to obtain a second mixed material; The second mixed material is mixed with FEVE type fluorocarbon resin and silicone polyether diol to sequentially perform a first crosslinking reaction and a second crosslinking reaction to obtain a third mixed material; the second crosslinking reaction is performed under the condition of adding a catalyst; Mixing the third mixed material with a hydrophobic agent to obtain a fourth mixed material; Mixing the fourth mixed material with a thixotropic agent and a portion of a diluent to obtain a fifth mixed material; The fifth mixed material is mixed with the remaining defoamer, the remaining diluent, the latent curing agent, the coupling agent and the dewatering agent to obtain the modified one-component polyurea waterproof coating.

8. The preparation method according to claim 7, characterized in that: The temperature of the condensation reaction is 80-90°C, and the time is 3-5 hours; the temperature of the first cross-linking reaction is 80-90°C, and the time is 40-50 minutes; the temperature of the second cross-linking reaction is 80-90°C, and the time is 1-2 hours.

9. Use of the modified one-component polyurea waterproof coating according to any one of claims 1 to 6 or the modified one-component polyurea waterproof coating prepared by the preparation method according to claim 7 or 8 in cold-region hydraulic concrete anti-freezing protection projects.

10. A hydraulic concrete protective coating structure, comprising a polyurea primer, a rough sealing layer and a polyurea top coating which are sequentially compounded on the surface of the hydraulic concrete base surface, wherein the polyurea top coating is a coating formed by the modified one-component polyurea waterproof coating according to any one of claims 1 to 6 or the modified one-component polyurea waterproof coating prepared by the preparation method according to claim 7 or 8.

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