A steel rust-proofing spraying material suitable for high salinization environment and a method of using the same

Abstract

The application relates to a spraying material, in particular to a steel bar rust prevention spraying material suitable for a high salinization environment and a use method thereof. The coating material is composed of the following components: a water-based epoxy resin, polyvinylidene fluoride, N-methyl pyrrolidone, sodium dodecyl sulfate and an additive. The coating material has good rust prevention performance, can form strong adhesion with cement, and is suitable for corrosion inhibition and rust prevention of steel bars in reinforced concrete structures in high-salt alkali characteristic land and retired land-based seawater culture land.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of spraying materials, in particular to a steel bar rust prevention spraying material suitable for a high salinization environment and a use method thereof. BACKGROUND

[0002] Data shows that the total area of existing saline-alkali land in China is 991,300 square kilometers, accounting for about 10% of the total land area. The northwest and northeast regions are traditional salinization areas. The Bohai Rim region, the Yangtze River Delta region, the Pearl River Delta region and the Hainan Island region also have the problem of land salinization, especially the retired or about-to-retire land-based mariculture plots have obvious high salinization characteristics. A large amount of disinfectants, bactericides, halogen compounds and sulfate ion compounds remaining in the soil hinder the natural recovery of the local plot ecosystem and cause serious corrosion to the underground reinforced concrete structure.

[0003] The high-concentration disinfectants, bactericides, halogen compounds and sulfate ion compounds remaining in the soil of the retired land-based mariculture plots not only cause serious diseases such as swelling, peeling and loosening to the cementitious materials and aggregates of the underground concrete, directly deteriorate the concrete material and strength, but also continuously corrode the steel bar surface layer as water molecules migrate to the inside of the concrete, reduce the cross-sectional area of the steel bar, and greatly reduce the bearing capacity and durability of the underground reinforced concrete structure.

[0004] Steel bars are the main force component of concrete structures. At present, there are many research results on new concrete materials suitable for salt-alkali environments and rust prevention materials mixed into concrete, but there are still few research results on steel bar rust prevention surface coating materials. It has great engineering application value to develop and prepare steel bar surface rust prevention materials with long service life, good effect and convenient spraying. SUMMARY

[0005] The application provides a steel bar rust prevention spraying material suitable for a high salinization environment. The spraying material has good rust prevention performance and can form strong adhesion with cement, and is suitable for corrosion inhibition and rust prevention of steel bars in the reinforced concrete structure in high-salt-alkali land and retired land-based mariculture plots. The specific scheme is as follows.

[0006] A steel bar rust prevention spraying material suitable for a high salinization environment is composed of the following components: water-based epoxy resin, polyvinylidene fluoride, N-methyl pyrrolidone, sodium dodecyl sulfate and additives. The preparation method of the spraying material is as follows:

[0007] Step (1): Take a certain amount of N-methyl pyrrolidone, add organic fluorine resin particles with particle size less than 200 mesh to it for complete dissolution, mix and then add to the aqueous epoxy resin, and add sodium dodecyl sulfate and additives, continuously stir to form a uniform emulsion to obtain solution A, wherein the mass ratio of N-methyl pyrrolidone: aqueous epoxy resin: polyvinylidene fluoride: sodium dodecyl sulfate: additive is 5-8: 40-50: 5-7: 4-6: 1-2; the molecular weight of polyvinylidene fluoride is 5000-200000;

[0008] Step (2): Take the curing agent and mix it with water to obtain solution B, the mass ratio of curing agent to water is 4-6: 1. The curing agent is aliphatic polyamine, specifically one or more of ethylenediamine, hexanediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine.

[0009] The organic fluorine resin is one of polyvinylidene fluoride, polytetrafluoroethylene, and super-hydrophobic modified polyvinylidene fluoride, with a molecular weight range of 5000-200000.

[0010] The above method for using the steel rust prevention spraying material suitable for high salinization environment comprises the following steps:

[0011] Step (a): rust removal for the steel to be coated;

[0012] Step (b): Take an appropriate amount of solution B and add it to solution A, stir until uniform and mature, wherein the mass ratio of solution A to solution B is 2-4: 1;

[0013] Step (c): Spray the steel with the solution matured in step (b) twice, with a thickness of 0.05-0.15 mm each time, and dry the surface between the two sprays.

[0014] Alternatively, a steel rust prevention spraying material suitable for high salinization environment is composed of the following components: aqueous epoxy resin, polyvinylidene fluoride, N-methyl pyrrolidone, sodium dodecyl sulfate, graphene, and additives;

[0015] The preparation method of the spraying material is as follows:

[0016] Step (1): First, add water to the dispersion container, then add sodium dodecyl sulfate to configure a dispersant solution, gradually add graphene powder while stirring, continue stirring for 20 min or more after the powder is completely added to obtain a primary dispersion liquid, transfer the primary dispersion liquid to an ultrasonic disperser for ultrasonic dispersion for 60 min or more to obtain a graphene slurry, then add the graphene slurry to the aqueous epoxy resin and stir to mix uniformly to obtain solution A; wherein the weight ratio of graphene to aqueous epoxy resin is 0.5-2: 100;

[0017] Step (2): Take a certain amount of N-methyl pyrrolidone, add polyvinylidene fluoride particles with a particle size of less than 200 mesh to it for sufficient dissolution, mix and then add to the aqueous epoxy resin, and add sodium dodecyl sulfate and additives, continuously stir to form a uniform emulsion, and obtain solution B; wherein the mass ratio of N-methyl pyrrolidone: aqueous epoxy resin: polyvinylidene fluoride: sodium dodecyl sulfate: additive is 5-8: 40-50: 5-7: 4-6: 1-2; the molecular weight of polyvinylidene fluoride is 5000-200000;

[0018] Step (3): Take the curing agent and mix it with water to obtain solution C, the mass ratio of curing agent to water is 4-6:1. The curing agent is an aliphatic polyamine, specifically one or more of ethylenediamine, hexanediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine.

[0019] The organic fluorine resin is one of polyvinylidene fluoride, polytetrafluoroethylene, and super-hydrophobic modified polyvinylidene fluoride, with a molecular weight range of 5000-200000.

[0020] The use method of the above-mentioned steel bar rust prevention spraying material suitable for high-saline and alkaline environments includes the following steps:

[0021] Step (a): rust removal of the steel bar to be coated;

[0022] Step (b): Take an appropriate amount of solution C and add it to solution A, stir evenly and mature, wherein the mass ratio of solution A to solution C is 1-3:1;

[0023] Step (c): Take an appropriate amount of solution C and add it to solution B, stir evenly and mature; wherein the mass ratio of solution B to solution C is 2-4:1;

[0024] Step (d): use the solution matured in step (b) to spray the steel bar twice, with a spraying thickness of 0.04-0.06mm, and dry the surface between sprays; use the solution matured in step (c) to spray twice, each time with a spraying thickness of 0.04-0.06mm, and dry the surface between sprays.

[0025] Further, the spraying thickness is the dry film thickness.

[0026] The spraying material of the present application has a long service life, good effect, is easy to spray, and has great engineering application value. The specific beneficial effects are as follows:

[0027] (1) The hydrophobic composition such as polyvinylidene fluoride is used as a coating material, which will combine with the hydrophobic end during the mixing process with the water-based epoxy resin, and will be partially coated with polyvinylidene fluoride during the curing and cross-linking process, forming a good bonding force. Polyvinylidene fluoride has good acid and alkali corrosion resistance, mechanical strength and super hydrophobicity, which can reduce the damage of the coating in the alkaline environment and maintain the long-lasting rust prevention performance; on the other hand, the super hydrophobicity gives the protective coating stronger resistance to chloride ions, preventing the penetration of corrosive liquids, especially when cracks occur in the coating due to unexpected factors, the hydrophobicity can further prevent the entry of moisture, maintaining long-term rust prevention ability.

[0028] (2) Two different components of paint are used for multi-layer coating, which brings better rust prevention performance and bonding strength. The addition of graphene in the bottom layer can effectively improve the conductivity of the coating and inhibit the electrochemical corrosion of the steel surface; at the same time, graphene has strong toughness and strength, which can improve the bonding strength of steel and cement. The outer layer adds super-hydrophobic material, which can fix the super-hydrophobic polymer in the coating through multiple spraying, while reducing the probability of defects, achieving the effect of reducing the penetration of corrosive liquids into the steel surface. DETAILED DESCRIPTION

[0029] The technical solutions and effects of the present application are further described below in conjunction with specific embodiments. Example 1

[0030] A kind of steel rust prevention spraying material suitable for high salinization environment, the preparation method is as follows:

[0031] Step (1): Take a certain amount of N-methyl pyrrolidone, add polyvinylidene fluoride particles with particle size less than 200 mesh to it for complete dissolution, mix and add to the water-based epoxy resin, and add sodium dodecyl sulfate and additives, continuously stir to form a uniform emulsion, to obtain solution A. The mass ratio of each component N-methyl pyrrolidone solvent: water-based epoxy resin: polyvinylidene fluoride: sodium dodecyl sulfate: additive is 5:40:5:4:1; the molecular weight of polyvinylidene fluoride is 5000-200000.

[0032] Step (2): Take the curing agent and mix it in water to get solution B, where the curing agent is ethylenediamine, and the mass ratio of ethylenediamine to water is 5:1.

[0033] When used, step (a): remove rust from the steel to be coated;

[0034] Step (b): Take an appropriate amount of solution B and add it to solution A, stir well and mature, where the mass ratio of solution A to solution B is 3:1;

[0035] Step (c): The solution matured in step (b) is used to spray the steel bars twice, with a thickness of 0.1 mm (dry film thickness) each time, and the surface is allowed to dry between the two sprays. Example 2

[0036] A steel bar rust-preventing spraying material suitable for high salinization and alkalization environment, the preparation method is as follows: step (1): first add water into the dispersion container, then add sodium dodecyl sulfate to configure the dispersant solution, gradually add graphene powder while stirring, continue stirring for more than 20 min after the powder is completely added for primary dispersion, transfer the primary dispersion liquid to an ultrasonic disperser for ultrasonic dispersion for more than 60 min, add the graphene slurry into the water-based epoxy resin, stir and mix uniformly to obtain solution A. The weight ratio of graphene and water-based epoxy resin is 1:100.

[0037] Step (2): Take a certain amount of N-methyl pyrrolidone, add polyvinylidene fluoride particles with a particle size of less than 200 mesh into it for complete dissolution, then add it into the water-based epoxy resin, and add sodium dodecyl sulfate and additives, continue to stir to form a uniform emulsion, and obtain solution B. The mass ratio of each component N-methyl pyrrolidone solvent: water-based epoxy resin: polyvinylidene fluoride: sodium dodecyl sulfate: additive is 5:40:5:4:1; the molecular weight of polyvinylidene fluoride is 5000-200000.

[0038] Step (3): Take the curing agent and mix it in water to obtain solution C, wherein the curing agent is ethylenediamine, and the mass ratio of each component ethylenediamine: water is 5:1.

[0039] In use, step (a): remove rust from the steel bars to be coated;

[0040] Step (b): Take an appropriate amount of solution C and add it to solution A, stir uniformly and mature, wherein the mass ratio of solution A: solution C is 2:1;

[0041] Step (c): Take an appropriate amount of solution C and add it to solution B, stir uniformly and mature; wherein the mass ratio of solution B: solution C is 3:1;

[0042] Step (d): Use the solution matured in step (b) to spray the steel bars twice, with a thickness of 0.05 mm (dry film thickness) each time, and the surface is allowed to dry between the two sprays; use the solution matured in step (c) to spray twice, with a thickness of 0.05 mm (dry film thickness) each time, and the surface is allowed to dry between the two sprays. Example 3

[0043] A steel bar rust-preventing spraying material suitable for high salinization and alkalization environment, the preparation and use steps are the same as those of example 1, and the difference from example 1 is that the polyvinylidene fluoride is replaced by polytetrafluoroethylene. Example 4

[0044] A kind of steel bar rust-proof spraying material suitable for high salinization environment, its preparation and use steps are same with example 2, and the difference with example 1 is that polyvinyl fluoride is replaced by polytetrafluoroethylene. Example 5

[0045] A kind of steel bar rust-proof spraying material suitable for high salinization environment, its preparation and use steps are same with example 2, and the difference with example 1 is that polyvinyl fluoride is replaced by super-hydrophobic modified polyvinyl fluoride.

[0046] Comparative examples 1-4

[0047] The difference between comparative examples 1-4 and examples 1-2 is shown in Table 1

[0048] Table 1 Summary of different preparation methods of comparative examples 1-4 and examples

[0049]

[0050] Performance test

[0051] The substrate uses Φ 10 mm steel bar, which is polished and rusted and kept dry for standby. After the coating is dry, it is placed at room temperature for one week before the solution immersion corrosion resistance and coated steel bar performance test, and the test results are shown in Table 2.

[0052] Solution immersion corrosion test of coating: the coated test piece is then placed in a solution prepared according to requirements, the solution is replaced every 3 days, and the surface of the test piece is checked and recorded every day. The configuration of the immersion solution is: 4% NaCl solution (mass fraction), 0.3 mol / L KOH solution + 4% NaCl solution.

[0053] The concrete pouring selects cement strength grade 42.5 ordinary portland cement, and the mixing ratio of cement, sand, gravel and other materials in the concrete is according to the conventional ratio. After four weeks of molding and curing, the pull-out test is carried out. The coated steel bar pull-out test is carried out in accordance with the standard DL / T5150-2017 “Hydraulic Concrete Test Procedures”.

[0054] Table 2-Performance test results

[0055]

[0056] It can be seen that the addition of hydrophobic substances such as polyvinyl fluoride can effectively improve the corrosion resistance of steel bars, while maintaining high adhesive strength. The addition of a certain amount of graphene can effectively improve the electrical conductivity of the coating and has a certain inhibitory effect on the electrochemical corrosion of the steel bar surface; at the same time, graphene has strong toughness and strength, which can improve the adhesive strength of steel bar and cement.

[0057] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A steel reinforcement corrosion inhibiting coating material suitable for use in high saline and alkaline environments, characterised in that, The preparation method of the spraying material is: Step (1): a certain amount of N-methyl pyrrolidone is taken, polyvinylidene fluoride particles with a particle size of less than 200 mesh are added for sufficient dissolution, and then added into the water-based epoxy resin, and sodium dodecyl sulfate and additives are added, and uniform emulsion is formed by continuous stirring to obtain solution A, wherein the mass ratio of N-methyl pyrrolidone: water-based epoxy resin: polyvinylidene fluoride: sodium dodecyl sulfate: additive is 5-8:40-50:5-7:4-6:1-2; the molecular weight of polyvinylidene fluoride is 5,000-200,000; Step (2): the curing agent is added into water for sufficient mixing to obtain solution B, and the mass ratio of the curing agent and water is 4-6:1; a proper amount of solution B is added into solution A for uniform stirring and aging, wherein the mass ratio of solution A:solution B is 2-4:

1.

2. The sprayed material of claim 1, wherein, The curing agent is aliphatic polyamine, and the aliphatic polyamine is one or more of ethylenediamine, hexanediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine.

3. A method of using a steel reinforcement corrosion inhibiting coating material suitable for use in highly saline and alkaline environments as claimed in claim 1 or claim 2, characterised in that, The method comprises the following steps: Step (a): rust removal is performed on the steel bar to be coated; Step (b): a proper amount of solution B is added into solution A for uniform stirring and aging, wherein the mass ratio of solution A:solution B is 2-4:1; Step (c): the solution aged in step (b) is used to spray the steel bar twice, and the spraying thickness is 0.05-0.15mm each time, and the surface is dried between the two times of spraying.

4. The method of use of claim 3, wherein, The spraying thickness is the dry film thickness.

5. A method of using a steel reinforcement corrosion inhibiting coating material suitable for use in high saline and alkaline environments, characterised in that, The preparation method of the spraying material is: Step (1): water is first added into a dispersion container, then sodium dodecyl sulfate is added to configure a dispersant solution, graphene powder is gradually added while stirring, and the powder is continuously stirred for more than 20 minutes after complete addition to perform initial dispersion to obtain an initial dispersion liquid, the initial dispersion liquid is transferred into an ultrasonic disperser for ultrasonic dispersion for more than 60 minutes to obtain a graphene slurry, and the graphene slurry is added into the water-based epoxy resin for uniform stirring to obtain solution A; wherein the mass ratio of graphene and water-based epoxy resin is 0.5-2:100; Step (2): a certain amount of N-methyl pyrrolidone is taken, polyvinylidene fluoride particles with a particle size of less than 200 mesh are added into the N-methyl pyrrolidone for sufficient dissolution, and then added into the water-based epoxy resin, and sodium dodecyl sulfate and additives are added, and uniform emulsion is formed by continuous stirring to obtain solution B; Wherein the mass ratio of N-methyl pyrrolidone: water-based epoxy resin: polyvinylidene fluoride: sodium dodecyl sulfate: additive is 5-8:40-50:5-7:4-6:1-2; the molecular weight of polyvinylidene fluoride is 5,000-200,000; Step (3): the curing agent is added into water for sufficient mixing to obtain solution C, and the mass ratio of the curing agent and water is 4-6:1; The use method comprises the following steps: Step (a): rust removal is performed on the steel bar to be coated; Step (b): a proper amount of solution C is added into solution A for uniform stirring and aging, wherein the mass ratio of solution A:solution C is 1-3:1; Step (c): take an appropriate amount of solution C into solution B, stir and mature; wherein the mass ratio of solution B: solution C is 2-4:1; Step (d): use the matured solution of step (b) to spray the steel bar twice, with a spraying thickness of 0.04-0.06 mm, and dry the surface between spraying; use the matured solution of step (c) to spray twice, with a spraying thickness of 0.04-0.06 mm each time, and dry the surface between spraying.

6. The method of use of claim 5, wherein, The curing agent is an aliphatic polyamine, and the aliphatic polyamine is one or more of ethylenediamine, hexanediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine.

7. The method of use of claim 5, wherein, The spraying thickness is the dry film thickness.

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