A corrosion-resistant, easy-to-clean coating for concrete structures, its method of preparation and method of use

Abstract

The application discloses a kind of anticorrosive easy-to-clean coatings for concrete structure, its preparation method and application method, belong to road anticorrosive coating production field.Anticorrosive easy-to-clean coatings are made of specific proportion water, water-based self-crosslinking emulsion, film forming aid, fumed silica, dispersing agent, hydrophobic modifier, wherein, the hydrophobic modifier is made by active polymerization reaction by fluorine-containing monomer, initiator, thioester chain transfer agent and hydrophilic monomer.Compared with prior art, the anticorrosive easy-to-clean coatings for concrete structure of the application has good easy-to-clean capacity while maintaining good durability, adhesion, and has good popularization and application value.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of road anticorrosive coating production, and particularly provides an anticorrosive and easy-to-clean coating for concrete structure, a preparation method and an application method thereof. BACKGROUND

[0002] During the hydration process of cement, a large number of micro pores, defects and hydroxyl groups are generated, resulting in strong hydrophilicity of the concrete material. Generally, the water on the surface of the concrete material is adsorbed to the inside of the material by capillary action generated by the micro pores. In cold regions, the concrete material surface layer is peeled off or cracked due to the volume expansion of water after freezing. The ions such as chloride ions and sulfate ions in the environment have an erosion effect, which causes electrochemical corrosion damage inside the reinforced concrete structure. These will seriously reduce the durability of the concrete material. In addition, the long-term accumulation of particulate matters such as dust on the surface of the structure has an adverse effect on the performance of the concrete, and the particulate matters are difficult to remove. It is of great significance to enhance the anticorrosive performance and easy-to-clean ability of the concrete material surface to improve the durability of the concrete structure.

[0003] The traditional water-based anticorrosive coating for concrete can play a closing and isolating effect on the surface of the concrete, but the surface contains groups such as epoxy and hydroxyl groups, so that the coating surface cannot form a water bead effect and does not have an easy-to-clean effect. Pollutants are easily adhered to the surface of the concrete structure, increasing the cost of cleaning and maintenance, thereby greatly reducing the aesthetic, functional and durability of the structure. Although the water-based anticorrosive coating for concrete prepared by using a water-based fluorine-containing emulsion can overcome the durability problem to some extent, it cannot control the hydrophobic effect of the coating according to the actual application environment. If only the amount of fluorine-containing emulsion in the coating system is adjusted, problems such as film-forming property and adhesion of the coating film system may be caused. SUMMARY

[0004] The present application is directed to the deficiencies of the prior art, and provides an anticorrosive and easy-to-clean coating for concrete structure, which has good durability, adhesion and easy-to-clean ability.

[0005] The further technical task of the present application is to provide a preparation method of the anticorrosive and easy-to-clean coating.

[0006] The further technical task of the present application is to provide an application method of the anticorrosive and easy-to-clean coating.

[0007] The technical solution adopted by the present application to solve the technical problem is: an anticorrosive and easy-to-clean coating for concrete structure, which is mainly made of water, water-based self-crosslinking emulsion, fumed silica, dispersing agent, film-forming aid and hydrophobic modifier, wherein the hydrophobic modifier is prepared by the following method:

[0008] S1. Dissolve 40-55 parts of fluorine-containing monomer, 1-8 parts of thio chain transfer agent and 0.1-0.5 parts of initiator in 40-50 parts of first organic solvent, react under inert gas condition at 50-80°C, and the product is purified and dried to obtain a macromolecular chain transfer agent;

[0009] S2. Dissolve 3-20 parts of the macromolecular chain transfer agent prepared in step S1, 10-35 parts of hydrophilic monomer and 0.03-0.08 parts of initiator in 20-50 parts of second organic solvent, react under inert gas condition at 50-80°C, and the product is purified and dried to obtain a hydrophobic modifier.

[0010] The weight ratio of each raw material of the above-mentioned anticorrosive easy-to-clean coating is preferably:

[0011]

[0012] The weight ratio of each raw material of the above-mentioned anticorrosive easy-to-clean coating is particularly preferably:

[0013]

[0014] The weight ratio of each raw material in the preparation step S1 of the hydrophobic modifier is particularly preferably:

[0015]

[0016] The weight ratio of each raw material in the preparation step S2 of the hydrophobic modifier is particularly preferably:

[0017]

[0018]

[0019] As a preference, the fluorine-containing monomer is octafluoropentyl methacrylate, perfluorooctyl methacrylate, dodecafluoroheptyl methacrylate and / or 2-(perfluorooctyl)ethyl methacrylate.

[0020] As a preference, the thio chain transfer agent is a dithioester, specifically, the dithioester used is a phenyl monofunctional dithioester, and its molecular structure is C6H5-CSS-R, wherein R can be -C(CH3)2C6H5, -CH2C6H5, -C4H6N, -C2H2N or -C6H5.

[0021] As a preference, the first organic solvent is tetrahydrofuran, methylpyrrolidone and / or dimethyl sulfoxide.

[0022] As a preference, the initiator is azobisisobutyronitrile, tert-butyl peroxyneodecanoate, tert-butyl peroxyneodecanoate and / or tert-amyl peroxyneodecanoate.

[0023] As preferred, the hydrophilic monomer is hydroxyethyl methacrylate, poly(ethylene glycol) methacrylate, sodium vinyl propyl sulfonate and / or acrylamide.

[0024] As preferred, the second organic solvent is dimethylformamide and / or dimethylacetamide.

[0025] As preferred, the hydrophobic modifier has a molecular weight of 15000-30000.

[0026] As preferred, the water-based self-crosslinking emulsion is a modified styrene-acrylic polymer emulsion.

[0027] As preferred, the dispersant is a high-molecular wet dispersant.

[0028] As preferred, the film-forming aid is alcohol ester dodecane and / or dipropylene glycol butyl ether.

[0029] As preferred, the method for preparing the anti-corrosion easy-to-clean coating for concrete structures comprises the following steps:

[0030] A1. Mix water, fumed silica and dispersant and stir thoroughly until the mixture is uniform;

[0031] A2. Add the water-based self-crosslinking emulsion and hydrophobic modifier to the mixture and continue stirring until the dispersion is uniform, obtaining the finished anti-corrosion coating for concrete.

[0032] As preferred, the stirring speed in step A1 is 1100-1500 rpm / min and the stirring time is 5-15 min; the stirring speed in step A2 is 550-700 rpm / min and the stirring time is 5-15 min.

[0033] The application method for the anti-corrosion easy-to-clean coating for concrete structures is characterized in that the thin spray process is adopted during construction, and the construction amount is (0.1-0.25) kg / m 2 , preferably (0.15-0.2) kg / m 2 .

[0034] Compared with the prior art, the anti-corrosion easy-to-clean coating for concrete structures, the method for preparing the same and the application method thereof have the following outstanding advantages:

[0035] (1) The coating surface has persistent hydrophobicity and long-acting water bead effect, which can reduce the adhesion of surface stains, prolong the cleaning period, reduce the use of cleaning agents, make it easier to remove stains and reduce maintenance costs.

[0036] (2) The self-crosslinking can provide excellent film-forming barrier protection for the concrete substrate, and no curing agent is needed, which is convenient for construction and simple to operate. The water-based emulsion is free of organic solvents and environmentally friendly.

[0037] (3) The hydrophobic modifier used is composed of a hydrophobic modification segment and a hydrophilic system anchoring segment. It has excellent compatibility in the water-based coating system, can be uniformly distributed in the water-based coating system, and the coating system is applied to the concrete surface. The hydrophilic segment of the hydrophobic modifier is compatible with the anchoring of the water-based system, and the fluorine-containing hydrophobic segment is automatically arranged to the air side due to its own hydrophobicity, thereby reducing the surface energy of the system.

[0038] (4) The traditional water-based fluorine-containing emulsion prepared concrete anticorrosive easy-to-clean coating, the water-based fluorine-containing emulsion is both a film-forming material and a hydrophobic material, and the hydrophobic effect can only be changed by adjusting the content of the fluorine-containing emulsion, and the change of the content of the fluorine-containing emulsion may cause the film-forming, adhesion and other properties of the system. The coating of the present application can control the hydrophobic effect of the coating by controlling the addition amount of the hydrophobic modifier without changing the film-forming property of the system according to the actual application environment. For example, when the traffic volume is small and the pollution is light, the product with 15 parts of hydrophobic modifier can be selected for the road side concrete facility. At this time, the water contact angle of the coating can reach more than 120°, and has a certain easy-to-clean effect, which can cope with ordinary road environment. When the traffic volume is large and the pollution is serious, the product with 30 parts of hydrophobic modifier can be selected for the road side concrete facility. At this time, the water contact angle of the coating can reach more than 140°, and has good easy-to-clean effect, which can cope with relatively harsh environment.

[0039] (5) During the preparation of the coating, the stirring speed is adjusted according to the characteristics of the materials, which can not only ensure that the fumed silica is fully dispersed to provide thixotropy and ensure the sagging property of the coating film, but also ensure the stability of the coating to avoid emulsion demulsification or damage to the molecular chain of the hydrophobic modifier.

[0040] (6) The thin spraying process is used in the construction process, which can fully utilize the roughness of the concrete itself and the roughness provided by the fumed silica material dispersed in the coating system, and a small amount of spraying can further exhibit the easy-to-clean effect of the coating. DETAILED DESCRIPTION

[0041] The present application will be further described below in conjunction with specific examples, but not as a limitation to the present application.

[0042] Unless otherwise specified, the content of each component used in the following is the content by weight percentage.

[0043]

Example One

[0044] Preparation method of hydrophobic modifier:

[0045] S1. Dissolve fluorine-containing monomer, first initiator and thioester chain transfer agent into first organic solvent, react at 70℃ under nitrogen atmosphere, wash the reaction product with methanol for 3 times, dry at 30℃ under vacuum to obtain active macromolecular chain transfer agent;

[0046] S2. Dissolve the obtained macromolecular chain transfer agent and hydrophilic monomer into second organic solvent, add initiator, react at 70℃ under nitrogen atmosphere, subject the product to dialysis cutoff by molecular weight 15000-30000 cutoff dialysis membrane, dry at 60℃ to obtain hydrophobic modifier.

[0047] The proportions of each raw material are shown in Table 1.

[0048] Table 1. Dosage of each raw material of hydrophobic modifier (unit: Kg)

[0049]

[0050]

[0051] Example 2

[0052] Preparation method of anticorrosive easy-to-clean coating

[0053] A1. Under the condition of stirring at 1300 rpm / min, add water, fumed silica and dispersant into a container, stir for 10 minutes to make the mixture uniform;

[0054] A2. Adjust the speed to 600 rpm / min, add waterborne self-crosslinking emulsion, film-forming aid and hydrophobic modifier, continue to stir for 10 minutes until uniformly dispersed, filter and pack to obtain the concrete anticorrosive coating.

[0055] The dosages of each raw material are shown in Table 2.

[0056] Table 2. Dosage of each raw material of anticorrosive easy-to-clean coating (unit: Kg)

[0057]

[0058]

[0059] Test example

[0060] (1) The anticorrosive easy-to-clean coating product 5 obtained in Example 2 was sprayed on concrete blocks at dosages of 0.1 kg / m 2 , 0.2 kg / m 2 , 0.3 kg / m 2 , and 0.5 kg / m 2 , respectively, and after natural drying, the water contact angle and rolling angle of the coating were tested by using a full-automatic contact angle tester, and the performance test data are shown in Table 3.

[0061] Table 3. Anticorrosive easy-to-clean coating product 5 test data

[0062] Product 5 usage Water contact angle Water roll-off angle 0.1 kg / m 2 ]] 143° 9° 0.2 kg / m 2 ]] 148° 7° 0.3 kg / m 2 ]] 137° 15° 0.5 kg / m 2 ]] 132° 20°

[0063] From the test results, it can be seen that the coating spraying amount also affects the easy-to-clean coating film of the system. Excessive spraying amount excessively covers the surface of the cement mortar material, causing the coating to be unable to fully utilize the roughness of the cement mortar material, and the self-cleaning performance is reduced.

[0064] (II) The anticorrosive easy-to-clean coating obtained in Example II was sprayed on the concrete block at a dosage of 0.2 kg / m 2 After natural drying, the coating water contact angle, rolling angle, water resistance, alkali resistance, coating film hardness, and adhesion performance were tested. The test data are shown in Table 4.

[0065] (1) Water contact angle test: a full-automatic contact angle tester was used to test the water droplets on the coating surface, and the planar contact angle and rolling angle of the coating were obtained by the instrument.

[0066] (2) Water and alkali resistance test: the test block with sprayed coating was placed in deionized water and saturated calcium hydroxide solution, respectively, and the appearance of the paint film was observed.

[0067] (3) Paint film adhesion test: the pull-off method was used to test the adhesion of the coating (GB / T 5210).

[0068] The test data are as follows

[0069] Table 4. Anticorrosive easy-to-clean coating test data obtained in Example II

[0070]

[0071] From the test results, it can be seen that the addition amount of the modified hydrophobic agent in the coating system has a greater effect on the preparation of the easy-to-clean coating film. When the addition amount is less than 30 parts, with the increase of the hydrophobic modifier, the water contact angle of the coating is larger, the rolling angle is smaller, and the easy-to-clean performance is better. When the addition amount is greater than 30 parts, the hydrophobic effect is not obvious, which may be because the addition amount of the modifier has reached a critical point, and increasing the addition amount will not improve the hydrophobicity. Moreover, due to the improvement of the hydrophobic effect, the water resistance and alkali resistance of the paint film are also improved.

[0072] Emulsion additive amount on the paint film adhesion is critical, emulsion content, paint film adhesion is good, side proof, if using a single fluorine-containing water-based self-crosslinking emulsion, if you want to adjust the easy cleaning effect according to the application environment, can only be through the change of fluorine-containing emulsion dosage, and the change of emulsion dosage may change the paint film adhesion, film forming property and other properties, and the product can change the hydrophobic modification dosage without changing the dosage of the film forming emulsion, which can adjust the hydrophobicity, without changing the adhesion of the paint film, which makes up for the defects of the single fluorine-containing traditional emulsion prepared concrete anticorrosive coating, and has good application value.

Claims

1. A corrosion resistant, easy-to-clean coating for concrete structures, characterized in that, Mainly made of water, water-based self-crosslinking emulsion, fumed silica, dispersant, film forming aid, hydrophobic modifier, the water-based self-crosslinking emulsion is modified styrene-acrylic emulsion, The hydrophobic modifier is prepared by the following method: S1. 40~55 parts of fluorine-containing monomer, 1~8 parts of sulfur chain transfer agent and 0.1~0.5 parts of initiator are dissolved in 40~50 parts of first organic solvent, and the reaction is carried out under inert gas condition at 50~80℃, and the product is purified and dried to obtain macromolecular chain transfer agent, The fluorine-containing monomer is octafluoropentyl methacrylate, perfluorooctyl methacrylate, dodecafluoroheptyl methacrylate and / or 2-(perfluorooctyl) ethyl methacrylate, The sulfur chain transfer agent is dithioester; S2. 3~20 parts of macromolecular chain transfer agent prepared in step S1, 10~35 parts of hydrophilic monomer and 0.03~0.08 parts of initiator are dissolved in 20~50 parts of second organic solvent, and the reaction is carried out under inert gas condition at 50~80℃, and the product is purified and dried to obtain hydrophobic modifier, The hydrophilic monomer is hydroxyethyl methacrylate, poly(ethylene glycol) methacrylate, sodium vinyl propyl sulfonate and / or acrylamide.

2. The anticorrosive, easy-to-clean coating for concrete structures according to claim 1, characterized in that: The weight ratio of each raw material is: Water 8~38 parts, Water-based self-crosslinking emulsion 40~60 parts, Fumed silica 0.5~5 parts, Dispersant 1~5 parts, Film forming aid 2~4 parts, Hydrophobic modifier 5~40 parts.

3. Anticorrosive easy-to-clean coating for concrete structures according to claim 1 or 2, characterized in that: The dispersant is a high molecular weight wet dispersant.

4. The anticorrosive, easy-to-clean coating for concrete structures according to claim 1 or 2, characterized in that: The film forming aid is alcohol ester twelve and / or dipropylene glycol butyl ether.

5. The anticorrosive and easy-to-clean coating for concrete structure according to claim 1 or 2, characterized in that: The first organic solvent in step S1 is tetrahydrofuran, methylpyrrolidone and / or dimethyl sulfoxide; The initiator in steps S1 and S2 is azobisdimethyl isobutyronitrile, tert-butyl peroxyneodecanoate, tert-butyl peroxyneodecanoate and / or tert-amyl peroxyneodecanoate; The second organic solvent in step S2 is dimethylformamide and / or dimethylacetamide.

6. The anticorrosive, easy-to-clean coating for concrete structures according to claim 1 or 2, characterized in that, The molecular weight of the hydrophobic modifier is 15000~30000.

7. A process for the preparation of a corrosion protective, easy-to-clean coating for concrete structures according to any one of claims 1 to 6, characterized in that Including the following steps: A1. Water, fumed silica, dispersant are mixed and stirred well until the mixture is uniform; A2. Add water-based self-crosslinking emulsion, film forming aid, hydrophobic modifier to the mixture, continue to stir until dispersed uniformly to obtain the finished product of concrete anticorrosive coating.

8. The preparation method of the anticorrosive and easy-to-clean coating for concrete structure according to claim 7, characterized in that: The stirring speed in step A1 is 1100~1500 rpm / min; The stirring speed in step A2 is 550~700 rpm / min.

9. Use of the anticorrosive, easy-to-clean coating for concrete structures according to any one of claims 1 to 6, characterized in that The construction process adopts thin spraying process, and the construction amount is (0.1-0.25) kg / m 2 .

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