Concrete solvent-free permeable long-acting protective coating and preparation method thereof

Abstract

The invention relates to a concrete solvent-free permeable long-acting protective coating and a preparation method thereof, and belongs to the technical field of protective coatings. The hydrogen-containing silicone oil is modified, an amino group and a six-membered ring structure are introduced into a hydrogen-containing silicone oil structure through a hydrosilylation reaction, the modified hydrogen-containing silicone oil is creatively used as a curing agent of the water-borne epoxy resin, and the modified hydrogen-containing silicone oil can be uniformly dispersed in the water-borne epoxy resin; and the protective paint can be fractured under the action of a catalyst, and forms stable chemical bonding with filler particles and the surface of a concrete base material, so that the binding capacity of matrix resin and the filler particles and the binding capacity of the protective paint and the surface of the concrete base material are enhanced, and the overall mechanical property and adhesive force of the protective paint are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of protective coatings, and in particular relates to a solvent-free penetrating long-lasting protective coating for concrete and a preparation method thereof. Background Art

[0002] Waterborne epoxy resin coating is an environmentally friendly coating system that uses water as a dispersion medium to replace traditional organic solvents. The organic solvent content in the system is extremely low, which significantly reduces VOC emissions during construction. However, the hardness and wear resistance of waterborne epoxy resin are usually low, and it is easily worn by external forces. The salt spray resistance of waterborne epoxy resin coatings after wear often decreases significantly. In addition, since waterborne epoxy resins have a low cross-linking density and are mostly hydrophilic, the water resistance of waterborne epoxy resin coatings is also relatively poor. Long-term exposure to humid environments may cause water absorption, softening, whitening, and even falling off.

[0003] By introducing an organosilicon structure into a water-based epoxy resin, the hydrophobicity of the water-based epoxy resin can be effectively improved, thereby improving the water resistance of the water-based epoxy resin coating. However, since silicone oil generally has a high viscosity and a low polarity, the large siloxane structure therein can effectively shield the active groups, making it difficult for the silicone oil and the epoxy resin to coexist stably. To address the above technical defects, the present invention provides a solvent-free penetrating long-lasting protective coating for concrete and a preparation method thereof. Summary of the Invention

[0004] The object of the present invention is to provide a solvent-free, penetrating, long-lasting protective coating for concrete and a preparation method thereof, so as to solve the problems mentioned in the above-mentioned background technology.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete comprises the following steps:

[0007] S1, using hydrogen-containing silicone oil and 4-cyclohexene-1,2-diamine to undergo a hydrosilylation reaction to obtain a curing agent;

[0008] S2, mixing water-based epoxy resin, fumed silica, inorganic pigment, titanium dioxide, film-forming agent and conductive metal powder to obtain component A;

[0009] S3, mixing the curing agent, curing accelerator and catalyst to obtain component B;

[0010] S4. After mixing component A and component B, spray them on the surface of the concrete substrate and heat and cure them to obtain a solvent-free penetrating long-lasting protective coating for concrete.

[0011] Among them, there is no difference in order between S2 and S3.

[0012] As a further preferred embodiment of the present invention, the hydrogen content of the hydrogen-containing silicone oil is 1 to 1.4%.

[0013] As a further preferred embodiment of the present invention, the water content of the waterborne epoxy resin is 2-4%.

[0014] As a further preferred embodiment of the present invention, the inorganic pigment is at least one of ferrous oxide and silver aluminum paste powder.

[0015] As a further preferred embodiment of the present invention, the film-forming aid is at least one of propylene glycol monomethyl ether and dipropylene glycol butyl ether.

[0016] As a further preferred embodiment of the present invention, the conductive metal powder is at least one of ultrafine zinc powder and ultrafine aluminum powder.

[0017] As a further preferred embodiment of the present invention, the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol.

[0018] As a further preferred embodiment of the present invention, the catalyst is at least one of tetramethylammonium silanol and tetramethylammonium hydroxide.

[0019] As a further preferred embodiment of the present invention, the mass ratio of hydrogen-containing silicone oil to 4-cyclohexene-1,2-diamine is 30-36:30-48.

[0020] As a further preference of the present invention, the mass ratio of waterborne epoxy resin, fumed silica, inorganic pigment, titanium dioxide, film-forming aid and conductive metal powder in component A is 76-82:3-4:10-15:5.5-6.5:4-6:11-16.

[0021] As a further preferred embodiment of the present invention, the mass ratio of the curing agent, the curing accelerator and the catalyst in component B is 45-65:0.2-0.6:0.06-0.08.

[0022] As a further preferred embodiment of the present invention, component A and component B are mixed in a mass ratio of 100-110:45-65.

[0023] As a further preferred embodiment of the present invention, the heat curing condition is curing at a temperature of 75 to 85° C. for 3 to 4 hours.

[0024] A solvent-free penetrating long-acting protective coating for concrete is prepared by any of the above preparation steps.

[0025] The present invention has at least one of the following beneficial effects:

[0026] 1) The present invention modifies hydrogenated silicone oil, introduces amino groups and six-membered ring structures into the structure of hydrogenated silicone oil by means of a hydrosilylation reaction, and creatively uses the modified hydrogenated silicone oil as a curing agent for waterborne epoxy resin. The rigid six-membered ring structure in the modified hydrogenated silicone oil structure can effectively inhibit the entanglement of silicone oil molecular chains by means of the steric hindrance effect of the ring space, inhibit the aggregation of the modified hydrogenated silicone oil in the waterborne epoxy resin, and promote the uniform dispersion of the modified hydrogenated silicone oil in the waterborne epoxy resin.

[0027] 2) The protective coating of the present invention comprises a waterborne epoxy resin, a silicone oil curing agent, and a catalyst. The catalyst can catalyze the cleavage of silanol bonds in the silicone oil curing agent under heating conditions. During curing, the silanol bonds in the silicone oil curing agent can be cleaved to produce silanol structures, which then react with the solid fillers (fumed silica, inorganic pigments, titanium dioxide, and the surface of conductive metal powder) in the protective coating and the hydroxyl groups in the concrete substrate structure to form stable chemical bonds. This significantly enhances the bonding ability between the solid fillers and the waterborne epoxy resin, reduces internal defects formed between the solid fillers and the matrix resin, and improves stress transfer efficiency, thereby enhancing the toughness and impact strength of the protective coating and significantly improving the adhesion of the waterborne epoxy resin-based protective coating to the concrete substrate surface.

[0028] 3) The present invention shortens the length of the silicone oil molecular chain by adding a catalyst to catalyze the cleavage of the silicon-oxygen bonds in the curing agent silicone oil, thereby reducing the viscosity of the silicone oil, making it easier for the amino groups in the silicone oil to contact the epoxy groups, and improving the curing efficiency of the water-based epoxy resin. The broken silicone oil can form a higher density cross-linked network in the epoxy resin network, thereby improving the heat resistance of the epoxy resin and effectively preventing the penetration of moisture and salt spray.

[0029] 4) The present invention uses modified hydrogenated silicone oil as a waterborne epoxy resin curing agent. The siloxane segments in the modified hydrogenated silicone oil structure can effectively reduce the surface energy of the protective coating and improve the hydrophobicity of the protective coating. The improved hydrophobicity can enable the protective coating to have good stain resistance and self-cleaning capabilities. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions of the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection requested by this application.

[0031] In the following examples, unless otherwise specified, the raw materials used are all commercially available products that can be purchased directly or can be prepared by conventional methods in the art. The Pt content of the Karstedt catalyst is 5000 ppm.

[0032] Example 1

[0033] A method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete comprises the following steps:

[0034] S1. Mix 36 parts of hydrogenated silicone oil with a hydrogen content of 1%, 48 parts of 4-cyclohexene-1,2-diamine, and 300 parts of toluene in a three-necked flask equipped with a thermometer and a condenser reflux device, start magnetic stirring, raise the system temperature to 80°C, and dropwise add a catalyst solution prepared by 3 parts of Karstedt catalyst and 0.06 parts of triethylamine to the three-necked flask. After the addition is complete, continue the reaction at a temperature of 80°C for 6 hours. After the reaction is completed, the reaction solution is evaporated to remove the solvent, the remaining liquid is dissolved with tetrahydrofuran, and precipitated with methanol. Then, the solid in the precipitate is filtered and separated to obtain a curing agent;

[0035] S2. By weight, 82 parts of waterborne epoxy resin, 4 parts of fumed silica, 15 parts of ferrous oxide, 6.5 parts of titanium dioxide, 6 parts of propylene glycol monomethyl ether, 10 parts of ultrafine aluminum powder, and 6 parts of ultrafine zinc powder were mixed to obtain component A;

[0036] S3. Mix 65 parts of a curing agent, 0.6 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 0.08 parts of tetramethylammonium silanol, by mass, to obtain component B.

[0037] S4. Mix 110 parts of component A and 65 parts of component B by mass, spray them on the surface of the concrete substrate and cure them at a temperature of 75°C for 4 hours to obtain a solvent-free penetrating long-lasting protective coating for concrete.

[0038] A solvent-free penetrating long-acting protective coating for concrete is prepared by any of the above preparation steps.

[0039] Example 2

[0040] A method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete comprises the following steps:

[0041] S1. Mix 30 parts by mass of hydrogenated silicone oil with a hydrogen content of 1.4%, 30 parts of 4-cyclohexene-1,2-diamine, and 240 parts of toluene in a three-necked flask equipped with a thermometer and a condensation reflux device. After starting magnetic stirring, raise the system temperature to 90°C, and dropwise add a catalyst solution prepared by 2 parts of Karstedt catalyst and 0.04 parts of triethylamine to the three-necked flask. After the addition is complete, continue the reaction at a temperature of 90°C for 10 hours. After the reaction is completed, evaporate the reaction solution to remove the solvent, dissolve the remaining liquid with tetrahydrofuran, and precipitate with methanol. Then, filter and separate the solid in the precipitate to obtain a curing agent.

[0042] S2. Mix 76 parts of waterborne epoxy resin, 3 parts of fumed silica, 10 parts of ferrous oxide, 5.5 parts of titanium dioxide, 4 parts of propylene glycol monomethyl ether, 8 parts of ultrafine zinc powder, and 3 parts of ultrafine aluminum powder to obtain component A.

[0043] S3. Mix 45 parts of a curing agent, 0.2 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 0.06 parts of tetramethylammonium silanol, by mass, to obtain component B.

[0044] S4. Mix 100 parts of component A and 45 parts of component B by mass, spray them on the surface of the concrete substrate and cure them at a temperature of 85°C for 3 hours to obtain a solvent-free penetrating long-lasting protective coating for concrete.

[0045] A solvent-free penetrating long-acting protective coating for concrete is prepared by any of the above preparation steps.

[0046] Example 3

[0047] A method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete comprises the following steps:

[0048] S1. Mix 33 parts of hydrogenated silicone oil with a hydrogen content of 1.2%, 39 parts of 4-cyclohexene-1,2-diamine, and 270 parts of toluene in a three-necked flask equipped with a thermometer and a condenser reflux device, start magnetic stirring, raise the system temperature to 85°C, and dropwise add a catalyst solution prepared by 2.5 parts of Karstedt catalyst and 0.05 parts of triethylamine to the three-necked flask. After the addition is complete, continue the reaction at a temperature of 85°C for 8 hours. After the reaction is completed, the reaction solution is rotary evaporated to remove the solvent, the remaining liquid is dissolved with tetrahydrofuran, and precipitated with methanol. Then, the solid in the precipitate is filtered and separated to obtain a curing agent;

[0049] S2. By weight, 79 parts of waterborne epoxy resin, 3.5 parts of fumed silica, 12.5 parts of inorganic pigment, 6 parts of titanium dioxide, 5 parts of dipropylene glycol butyl ether, 9 parts of ultrafine zinc powder and 4.5 parts of ultrafine aluminum powder were mixed to obtain component A;

[0050] S3. Mix 57.5 parts of a curing agent, 0.4 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 0.07 parts of tetramethylammonium hydroxide, by mass, to obtain component B.

[0051] S4. Mix 105 parts of component A and 57.5 parts of component B by mass, spray them on the surface of the concrete substrate and cure them at a temperature of 80°C for 3.5 hours to obtain a solvent-free penetrating long-lasting protective coating for concrete.

[0052] A solvent-free penetrating long-acting protective coating for concrete is prepared by any of the above preparation steps.

[0053] Comparative Example 1

[0054] The difference between this embodiment and comparative example 3 is that the curing agent is not prepared separately, but the 4-cyclohexene-1,2-diamine used for preparing the curing agent is directly used as the curing agent in component B.

[0055] A method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete comprises the following steps:

[0056] S1. By weight, 79 parts of waterborne epoxy resin, 3.5 parts of fumed silica, 12.5 parts of inorganic pigment, 6 parts of titanium dioxide, 5 parts of dipropylene glycol butyl ether, 9 parts of ultrafine zinc powder and 4.5 parts of ultrafine aluminum powder were mixed to obtain component A;

[0057] S2. Mix 39 parts by mass of 4-cyclohexene-1,2-diamine, 0.4 parts of 2,4,6-tris(dimethylaminomethyl)phenol, and 0.07 parts of tetramethylammonium hydroxide to obtain component B.

[0058] S3. Mix 105 parts of component A and 39 parts of component B by mass, spray them on the surface of the concrete substrate and cure them at a temperature of 80°C for 3.5 hours to obtain a solvent-free penetrating long-lasting protective coating for concrete.

[0059] A solvent-free penetrating long-acting protective coating for concrete is prepared by any of the above preparation steps.

[0060] Experimental Example 1

[0061] The protective coatings obtained after curing in Examples 1 to 3 and Comparative Example 1 were subjected to performance tests, respectively. The hydrophobicity, pencil hardness, impact strength, glass transition temperature, salt spray resistance and adhesion of each component sample were tested. The test results are shown in Table 1.

[0062] Hydrophobicity test: Use a water contact angle tester to test the water contact angle of each component sample. The larger the water contact angle, the better the hydrophobicity.

[0063] Pencil hardness test: Test in accordance with the national standard GB / T 6739-2022 "Paints and varnishes - Determination of film hardness by pencil method";

[0064] Impact strength test: Tested in accordance with the national standard GB / T 1732-2020 "Determination of impact resistance of paint films";

[0065] Glass transition temperature test: Tested in accordance with the national standard GB / T 15022.2-2017 "Resin-based active composites for electrical insulation";

[0066] Salt spray resistance: Tested in accordance with the national standard GB / T 1771-2007 "Paints and varnishes - Determination of resistance to neutral salt spray";

[0067] Adhesion test: Test according to the national standard GB / T 5210-2006 "Paint and varnish adhesion test by pull-off method".

[0068] Table 1

[0069] project Example 1 Example 2 Example 3 Comparative Example 1 Water contact angle (°) 126 122 128 53 Pencil hardness 6H 7H 6H 2H Impact strength (cm) 70 69 72 43 Glass transition temperature (℃) 143 146 141 108 Salt spray resistance test (2000h salt spray resistance test) pass pass pass Fail Adhesion (MPa) 9.82 9.43 10.37 3.42

[0070] As can be seen from Table 1, the protective coatings in Examples 1 to 3 have good mechanical properties and toughness as a whole, good adhesion to the concrete surface, excellent salt spray resistance, and good hydrophobicity.

[0071] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0072] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete, characterized in that: The following steps are involved: A curing agent is obtained by a silylation reaction between hydrogenated silicone oil and 4-cyclohexene-1,2-diamine. Then, a water-based epoxy resin, fumed silica, inorganic pigment, titanium dioxide, a film-forming aid and a conductive metal powder are evenly mixed to obtain component A. A curing agent, a curing accelerator and a catalyst are evenly mixed to obtain component B. Components A and B are mixed, sprayed on the surface of a concrete substrate, and heated and cured to obtain a solvent-free penetrating long-lasting protective coating for concrete.

2. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: The hydrogen content of the hydrogen-containing silicone oil is 1-1.4%, and the water content of the water-based epoxy resin is 2-4%.

3. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: The inorganic pigment is at least one of ferrous oxide and silver aluminum paste powder, and the conductive metal powder is at least one of ultrafine zinc powder and ultrafine aluminum powder.

4. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: The film-forming aid is at least one of propylene glycol monomethyl ether and dipropylene glycol butyl ether, the curing accelerator is 2,4,6-tris(dimethylaminomethyl)phenol, and the catalyst is at least one of tetramethylammonium silanol and tetramethylammonium hydroxide.

5. The method for preparing a solvent-free penetrating long-lasting protective coating for concrete according to claim 1, characterized in that: The mass ratio of hydrogen-containing silicone oil to 4-cyclohexene-1,2-diamine is 30-36:30-48.

6. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: The mass ratio of waterborne epoxy resin, fumed silica, inorganic pigment, titanium dioxide, film-forming aid and conductive metal powder in component A is 76-82:3-4:10-15:5.5-6.5:4-6:11-16.

7. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: The mass ratio of the curing agent, curing accelerator and catalyst in component B is 45-65:0.2-0.6:0.06-0.

08.

8. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: Component A and component B are mixed in a mass ratio of 100-110:45-65.

9. The method for preparing a solvent-free, penetrating, long-lasting protective coating for concrete according to claim 1, characterized in that: The heat curing condition is to cure at a temperature of 75 to 85°C for 3 to 4 hours.

10. A solvent-free penetrating long-lasting protective coating for concrete, characterized in that: The solvent-free penetrating long-lasting protective coating for concrete is prepared by the preparation method described in any one of claims 1 to 9.