A water-based shop primer and preparation method thereof

Abstract

The present invention relates to the field of coatings, and particularly to a waterborne shop primer and a preparation method thereof. The waterborne shop primer comprises a component A and a component B, wherein the component A comprises zinc powder and a filler, and the component B comprises ethyl silicate, polyethylene glycol, an acidic solution, and deionized water. By using modified ethyl silicate, the present invention avoids the introduction of alkali metals, thereby resolving the problem of reduced initial water resistance and subsequent coating adhesion caused by residual alkali metal ions in common alkali metal silicate systems. Furthermore, the coating exhibits excellent corrosion resistance, weather resistance, and complementary adhesion. When used for temporary protection of steel plates in ships and large-scale industries, the coating can reduce the damage rate of the steel plates, improve adhesion to the subsequent coating, reduce subsequent construction costs, and improve overall construction quality.

Description

Technical Field

[0001] The present invention relates to the field of coatings, and in particular to a water-based shop primer and a preparation method thereof. Background Art

[0002] Shop primers are widely used in shipbuilding and large industrial steel structure construction. Their primary purpose is to provide temporary corrosion protection for steel substrates during construction. In addition to providing a certain degree of corrosion protection, shop primers also require good adhesion to subsequent primers for ease of application.

[0003] Traditional shop primers are solvent-based coatings based on ethyl silicate hydrolyzate and zinc powder. These contain large amounts of volatile organic solvents, which can have adverse environmental impacts. With the country's increasing emphasis on environmental protection, solvent-based shop primers are no longer able to meet new market demands, and water-based shop primers are becoming a key development direction for shop primers.

[0004] Waterborne shop primers typically use water-based alkali metal silicates, colloidal silica, and zinc powder as their primary raw materials. The film is formed through the hydrolysis and curing of the alkali metal silicates, forming an inorganic Si—O—Si network structure. However, this inorganic network structure is brittle, and the alkali metal silicates contain a large amount of alkali metal cations. After hydrolysis and curing, these alkali metal cations remain in the paint film, affecting the coating's corrosion resistance and adhesion to the next coating.

[0005] To solve the above problems, the existing technology usually adopts a water-based organic resin or emulsion modification method to reduce the content of alkali metal cations in the coating and achieve toughening modification of the coating.

[0006] For example, Chinese patent document CN108300052A discloses a self-curing weldable waterborne shop primer and its preparation method. The primer comprises a base material and a curing agent. The base material includes 10-100 parts zinc powder, 0-60 parts micaceous iron oxide, and 0-30 parts filler. The curing agent comprises 30-100 parts lithium potassium silicate solution, 0-60 parts modified emulsion, 0-1 part fumed silica, 0-1 part wetting agent, and 0-8 parts water. By modifying the lithium potassium silicate solution with a special emulsion, a waterborne shop primer with excellent performance is prepared.

[0007] Chinese patent document CN109943109A discloses a waterborne shop primer composition comprising a base material and a curing agent. The base material comprises the following components, by weight: 30-50% zinc powder; 20-30% ferrophosphorus powder; 15-20% quartz powder; and 15-20% filler. The curing agent comprises 50-70% silicate solution; 13-23% carbon-titanium cage resin; 0.2-0.5% leveling agent; 0.2-0.5% wetting agent; 0.2-0.5% defoaming agent; and 14-26% water. Modification with the carbon-titanium cage resin emulsion improves the coating's high-temperature resistance and adhesion to subsequent coatings.

[0008] Chinese patent document CN110982312A discloses a water-based shop primer with excellent initial water resistance and its preparation method. The primer comprises component A and component B; component A includes zinc powder, rust-proof filler, and filler; and component B includes potassium silicate, lithium silicate, colloidal silica, a water-based hyperbranched resin, additives, and water. Modification of the water-based hyperbranched resin increases the crosslink density of the coating.

[0009] Although the above process reduces the amount of alkali metal silicate in the formula by introducing water-based organic resin or emulsion, there is still the problem of alkali metal cations remaining in the paint film, which affects the corrosion resistance of the paint film and the adhesion of subsequent coatings. Summary of the Invention

[0010] In order to solve the problem of residual alkali metal cations after curing of existing water-based shop primers, the present invention provides a water-based shop primer, comprising component A and component B, wherein the component A comprises zinc powder and a filler, and the component B comprises ethyl silicate, polyethylene glycol, an acidic solution and deionized water.

[0011] Furthermore, the component A comprises 25-60 parts by mass of zinc powder and 40-75 parts by mass of filler.

[0012] Furthermore, the component B comprises, in parts by mass, 20-30 parts of ethyl silicate, 1-9.7 parts of polyethylene glycol, 0.3-0.6 parts of acidic solution and 65-70 parts of deionized water.

[0013] Furthermore, the fineness of the zinc powder is 500-1500 mesh.

[0014] Furthermore, the filler is one or more of ferrophosphorus powder, composite iron-titanium powder, zinc phosphate, zinc oxide and red iron oxide.

[0015] Furthermore, the polyethylene glycol is an oligomer with a molecular weight ≤ 600.

[0016] Furthermore, the acidic solution is one or more of sulfuric acid solution, hydrochloric acid solution, and nitric acid solution.

[0017] Furthermore, the concentration of the acidic solution is 0.5-1 mol / L.

[0018] Furthermore, the mass ratio of component A to component B is (2-4):1.

[0019] The present invention also provides a method for preparing the above-mentioned water-based shop primer, comprising the following preparation methods of component A and component B:

[0020] The preparation method of the component A is as follows: zinc powder and filler are added into a preparation container and mixed evenly;

[0021] The preparation method of the second component is as follows: first, ethyl silicate and polyethylene glycol are mixed, the mixture is heated to 50-70° C., an acidic solution is slowly added dropwise to the mixture under stirring, the mixture is kept warm for reaction for 20-60 minutes, the mixture is cooled to room temperature, and water is added for dilution to obtain the product.

[0022] Preferably, the stirring speed is 200-400 r / min.

[0023] Preferably, the acidic solution is added dropwise within 10-30 minutes.

[0024] Compared with the prior art, the water-based shop primer provided by the present invention has the following beneficial effects:

[0025] The present invention hydrophilically modifies alcohol-soluble ethyl silicate with polyethylene glycol to produce a water-soluble modified ethyl silicate. This avoids the introduction of alkali metals, thereby resolving the problem of reduced initial water resistance and subsequent coating adhesion due to residual alkali metal ions in common alkali metal silicate systems. When the two components of the waterborne shop primer are mixed, the addition of zinc powder changes the pH of the system from weakly acidic to alkaline, further hydrolyzing the ethyl silicate and curing it to form a paint film. The waterborne shop primer provided by the technical solution of the present invention forms a denser film, exhibiting excellent corrosion resistance, weather resistance, and complementary adhesion. This coating can be used for temporary protection of steel plates in ships and large-scale industries, reducing steel plate damage rates and improving adhesion to subsequent coatings, thereby reducing subsequent construction costs and improving overall construction quality. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] The invention provides a water-based shop primer comprising a component A and a component B. The component A comprises zinc powder and a filler, and the component B comprises ethyl silicate, polyethylene glycol, an acidic solution and deionized water.

[0028] Wherein, the component A comprises 25-60 parts by mass of zinc powder and 40-75 parts by mass of filler.

[0029] The component B comprises, in parts by mass, 20-30 parts of ethyl silicate, 1-9.7 parts of polyethylene glycol, 0.3-0.6 parts of acidic solution and 65-70 parts of deionized water.

[0030] The fineness of the zinc powder is 500-1500 mesh.

[0031] The filler is one or more of ferrophosphorus powder, composite iron-titanium powder, zinc phosphate, zinc oxide and red iron oxide.

[0032] The polyethylene glycol is an oligomer with a molecular weight of ≤600.

[0033] The acidic solution is one or more of sulfuric acid solution, hydrochloric acid solution and nitric acid solution.

[0034] The concentration of the hydrochloric acid solution is 0.5-1 mol / L.

[0035] The mass ratio of component A to component B is (2-4):1.

[0036] The present invention also provides a method for preparing a water-based shop primer, comprising the following preparation methods of component A and component B:

[0037] The preparation method of the component A is as follows: zinc powder and filler are added into a preparation container and mixed evenly;

[0038] The preparation method of the second component is as follows: first, ethyl silicate and polyethylene glycol are mixed, the mixture is heated to 50-70° C., an acidic solution is slowly added dropwise to the mixture under stirring, the mixture is kept warm for reaction for 20-60 minutes, the mixture is cooled to room temperature, and water is added for dilution to obtain the product.

[0039] Preferably, the stirring speed is 200-400 r / min.

[0040] Preferably, the acidic solution is added dropwise within 10-30 minutes.

[0041] The present invention also provides the following examples and comparative examples (unit: weight parts), as shown in Table 1 below:

[0042] Table 1

[0043]

[0044] The zinc powder of Example 1 was 500 mesh, the zinc powder of Example 2 was 800 mesh, and the zinc powder of Example 3 was 1500 mesh.

[0045] The filler of Example 1 is ferrophosphorus powder, the filler of Example 2 is a composition of composite iron-titanium powder and zinc phosphate mixed in a mass ratio of 1:1, and the filler of Example 3 is a composition of zinc oxide and red iron oxide mixed in a mass ratio of 1:1;

[0046] The molecular weight of the polyethylene glycol in Example 1 is 300, the molecular weight of the polyethylene glycol in Example 2 is 400, and the molecular weight of the polyethylene glycol in Example 3 is 600;

[0047] The acidic solution of Example 1 is a 0.5 mol / L hydrochloric acid solution, the acidic solution of Example 2 is a 0.7 mol / L hydrochloric acid solution, and the acidic solution of Example 3 is a 1 mol / L hydrochloric acid solution.

[0048] The only difference between Comparative Example 1 and Example 1 is that polyethylene glycol is not added, and the rest is the same as Example 1.

[0049] The above raw materials are all commercially available or prepared by conventional methods.

[0050] The above examples and comparative examples were prepared by the following preparation method to prepare component A and component B:

[0051] The preparation method of component A is:

[0052] Weigh zinc powder and filler according to the formula, mix on a shaker for 10 minutes, and obtain component A.

[0053] The preparation method of component B is:

[0054] Ethyl silicate and polyethylene glycol were weighed according to the formula and mixed. The mixture was heated to 60°C. Hydrochloric acid solution was slowly added dropwise to the mixture at a stirring speed of 300 r / min, and the addition was completed within 20 minutes. Subsequently, the mixture was kept at 60°C for 30 minutes, cooled to room temperature, and diluted with water in the formula to obtain component B.

[0055] The waterborne shop primer is obtained by uniformly mixing component A and component B. The mass ratio of component A and component B in Example 1 and Comparative Example 1 is 4:1, the mass ratio of component A and component B in Example 2 is 3:1, and the mass ratio of component A and component B in Example 3 is 2:1.

[0056] Comparative Example 2

[0057] Water-based shop primer prepared according to Chinese patent document CN109943109A.

[0058] The above examples and comparative examples were subjected to performance tests, and the test results are shown in Table 2.

[0059] Table 2

[0060]

[0061]

[0062] Among them, the matching adhesion refers to the adhesion test of the matching coating after spraying solvent-based epoxy anti-rust paint on the surface 24 hours after the water-based shop primer is applied, curing at room temperature for 7 days;

[0063] “ / ” indicates no relevant data.

[0064] As shown in Table 2, the waterborne shop primer examples provided by the present invention meet national standards for film thickness, drying time, salt spray resistance, weather resistance, and supporting adhesion. In actual use, the coatings exhibit excellent corrosion resistance and adhesion to subsequent coatings, meeting the requirements for temporary protection of ships and large industrial steel substrates. Comparative Example 1, due to the lack of hydrophilic modification with polyethylene glycol and the immiscible nature of ethyl silicate with water, exhibited in-can delamination of the coating. Comparing the examples with Comparative Example 2, it can be seen that the waterborne shop primers provided by the present invention exhibit superior weather resistance and supporting adhesion.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water-based shop primer, characterized in that: The invention comprises a component A and a component B, wherein the component A comprises zinc powder and a filler, and the component B comprises ethyl silicate, polyethylene glycol, an acidic solution, and deionized water; the component A comprises, by weight, 25-60 parts of zinc powder and 40-75 parts of filler; the component B comprises, by weight, 20-30 parts of ethyl silicate, 1-9.7 parts of polyethylene glycol, 0.3-0.6 parts of acidic solution, and 65-70 parts of deionized water; and the concentration of the acidic solution is 0.5-1 mol / L; The preparation method of the second component is as follows: first, ethyl silicate and polyethylene glycol are mixed, the mixture is heated to 50-70°C, and an acidic solution is slowly added dropwise to the mixture under stirring, the mixture is kept warm for reaction for 20-60 minutes, the mixture is cooled to room temperature, and water is added for dilution to obtain the product; The filler is one or more of ferrophosphorus powder, composite iron-titanium powder, zinc phosphate, zinc oxide and red iron oxide; The polyethylene glycol is an oligomer with a molecular weight of ≤600; The acidic solution is one or more of sulfuric acid solution, hydrochloric acid solution, and nitric acid solution; The mass ratio of component A to component B is (2-4):

1.

2. The waterborne shop primer according to claim 1, characterized in that: The fineness of the zinc powder is 500-1500 mesh.

3. A method for preparing a waterborne shop primer according to any one of claims 1 to 2, characterized in that: The invention relates to a preparation method comprising the following components A and B: The preparation method of the component A is as follows: zinc powder and filler are added into a preparation container and mixed evenly; The preparation method of the second component is as follows: first, ethyl silicate and polyethylene glycol are mixed, the mixture is heated to 50-70° C., an acidic solution is slowly added dropwise to the mixture under stirring, the mixture is kept warm for reaction for 20-60 minutes, the mixture is cooled to room temperature, and water is added for dilution to obtain the product.

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