Preparation method of waxy anticorrosive paint resistant to seawater corrosion

Abstract

A preparation method of a waxy anticorrosive coating resistant to seawater corrosion relates to a preparation method of an anticorrosive coating, and comprises the following steps: firstly, adding an emulsifier into deionized water, stirring and mixing, adding cardanol polyol and methacrylic acid, and emulsifying to obtain a matrix emulsion; adding an initiator into water to obtain an initiator solution; under the protection of nitrogen atmosphere, dropwise adding the initiator solution into the matrix emulsion to obtain a water-soluble polymer; and uniformly stirring and mixing the water-soluble polymer, the water-based fine oxidized polyethylene wax emulsion and the metal aluminum powder filler to obtain the coating. The coating prepared by the invention has the effects of water resistance, rust resistance, wear resistance and the like, and can provide lasting protection for a matrix. Meanwhile, the coating does not contain an organic solvent, is environment-friendly, non-toxic and harmless, can be conveniently coated on various base materials, and is high in drying speed.

Description

Technical Field

[0001] The invention relates to a coating preparation method, in particular to a method for preparing a waxy anti-corrosion coating resistant to seawater corrosion. Background Art

[0002] The marine environment is a complex corrosion environment. Seawater corrosion is mainly local corrosion, that is, corrosion that starts from the surface of the component and occurs in a very small area, such as galvanic corrosion, pitting corrosion, crevice corrosion, etc. The corrosion rate of metals in seawater is not only related to the composition and structure of the metal itself, but also closely related to the environmental factors of seawater. For example, waves, tides, and currents produce low-frequency reciprocating stress and impact on metal components, and marine microorganisms, attached organisms and their metabolites all have a direct or indirect acceleration effect on the corrosion process. Therefore, coastal facilities, docks, piers, lighthouses, buoys and other steel structures and reinforced concrete structures all need anti-corrosion protection.

[0003] There are many types of corrosion of steel structures in marine engineering. The heavy-duty anti-corrosion coatings that are currently used more frequently are: epoxy anti-corrosion coatings, fluorocarbon anti-corrosion coatings, polyurethane anti-corrosion coatings, rubber anti-corrosion coatings, organic (inorganic) silicone resin coatings, polyurea elastomer anti-corrosion coatings, glass flake heavy-duty anti-corrosion coatings and organic (inorganic) zinc-rich coatings.

[0004] 1. Epoxy anti-corrosion coating Epoxy anti-corrosion coatings are made of epoxy resin as the main component, mixed with pigments, driers, additives, etc. Epoxy resin coatings have excellent properties, such as high adhesion, high strength, chemical resistance and wear resistance. They are one of the earliest and most widely used types of heavy-duty anti-corrosion coatings in the field of marine heavy-duty anti-corrosion.

[0005] 2. Fluorocarbon anti-corrosion coating Fluorocarbon anti-corrosion coatings use fluorine-containing resin as the main film-forming substance. The fluorine atom has a large electronegativity and a small radius, the CF bond is short, the bond energy is strong, and the polarization rate is low. This type of coating exhibits super weather resistance, heat resistance, and chemical resistance, and has excellent self-cleaning properties, anti-fouling properties, and super corrosion resistance.

[0006] 3. Rubber anti-corrosion coating Rubber coatings use natural rubber derivatives or synthetic rubber as the main film-forming material. Chlorosulfonated polyethylene anticorrosion coatings and chlorinated rubber anticorrosion coatings are widely used. Rubber coatings are non-toxic and odorless, non-irritating to the skin, and the coating film has strong corrosion resistance and strong adhesion to the substrate. It also has the advantages of quick drying, water resistance, wear resistance, and anti-aging. Rubber anticorrosion coatings are mainly used in ships, sluices, chemical industries, and other fields.

[0007] 4. Silicone resin coating Silicone resin coating is an elemental organic coating with silicone resin or modified silicone resin as the main film-forming substance. It is mainly divided into pure silicone resin coating and modified silicone resin coating. It has strong heat and cold resistance, and excellent insulation, adhesion, flexibility, mildew resistance and other properties. Modified silicone resin is more widely used, including mechanical mixing type and polycondensation type. Silicone resin can be modified by adding different fillers or pigments to enhance its heat resistance, insulation and weather resistance.

[0008] 5. Polyurethane anti-corrosion coating Polyurethane coatings are a common type of coatings that have similar properties to epoxy coatings and are divided into two-component and one-component polyurethane coatings. In addition to urethane bonds, polyurethanes also contain many -OH, -NCO and unsaturated double bonds. The coatings have excellent properties such as acid and alkali resistance, oil resistance, corrosion resistance, high and low temperature resistance, and wear resistance. Polyurethane coatings are high-solid and low-VOC coatings with very low environmental pollutant emissions. Polyurethane coatings have strong adhesion to the substrate, excellent physical and mechanical properties, and strong decorative properties. They can be used as topcoats in heavy corrosion protection fields.

[0009] 6. Polyurea elastomer anti-corrosion coating Polyurea elastomer coatings are generated by the reaction of amino compounds and isocyanates and are mostly used for corrosion protection of offshore bridges. Successfully developed in the United States in the late 1980s, they have been widely used worldwide due to their excellent performance. They are new, efficient, easy-to-apply two-component pure polyurea elastomer coatings developed after high-solid, powder coatings, water-based coatings, and light-curing coatings. This high-thickness elastomer coating has obvious characteristics, such as high solid content, green and environmentally friendly, thick, dense and flexible coatings, strong adhesion to the substrate, excellent UV resistance, impact resistance and other properties, and easy construction.

[0010] 7. Glass flake heavy anti-corrosion coating Glass flake anticorrosive coating is a type of coating made of resin as the main film-forming substance, special glass flakes as aggregates, and appropriate additives. The characteristics are that the glass flakes are thin, overlap with the coating, inhibit the penetration of the medium, and have excellent shielding effect; the coating has strong adhesion and mechanical properties, corrosion resistance, and strong toughness; the flakes reduce the stress between the coating and the substrate, preventing the coating from cracking and falling off; the flakes reflect a large amount of ultraviolet rays in the coating, and the resin has excellent ultraviolet resistance, weather resistance, and aging resistance.

[0011] 8. Zinc-rich coating Zinc-rich paint is an epoxy powder paint with zinc powder as filler, mainly including organic and inorganic zinc-rich paint, which is widely used on offshore bridges, large steel structures, ships and other equipment. The anti-corrosion mechanism of zinc-rich paint includes shielding effect, electrochemical protection, coating self-repair effect, and passivation effect. Organic zinc-rich paint mostly uses epoxy resin and polyurethane resin as film-forming substances; inorganic zinc-rich paint uses water-based silicate resin, ethyl silicate and other film-forming substances. Organic zinc-rich paint has good construction performance, low substrate and strong surface treatment, but its heat resistance, conductivity, solvent resistance and other properties are inferior to inorganic types. Organic types are miscible with most coatings, and there is a synergistic effect between matching coatings.

[0012] From the above information, we can know that the common seawater resistant heavy-duty anti-corrosion coatings are mainly made by adding granular nano-scale inorganic fillers such as SiO2, TiO2, ZnO, BaSO4 and other inorganic nano-fillers and flaky fillers such as flaky mica, mica iron oxide, graphite, flaky zinc powder, stainless steel and glass flakes into organic coatings. The organic coatings used are mainly various natural resins and synthetic resins: Such as asphalt, raw lacquer, natural rubber, epoxy resin, phenolic resin, furan resin, polyester resin, polyurethane resin and vinyl resin, perchlorethylene resin and fluorine-containing resin, etc. The biggest disadvantage of the above-mentioned polar organic coatings is that the organic coatings will discolor, peel, mildew, and become dusty after 2 years of use, affecting their service life.

[0013] Microcrystalline modified polyethylene wax has excellent cold resistance, heat resistance, chemical resistance and wear resistance, making it an excellent alternative to traditional organic coatings. Summary of the invention

[0014] The object of the present invention is to provide a method for preparing a waxy anti-corrosion coating resistant to seawater corrosion, in which method microcrystalline modified polyethylene wax is distributed in the coating to protect the coating film, prevent scratches and abrasions and provide damage resistance; the low friction coefficient of the microcrystalline modified polyethylene wax is utilized to provide the coating film with excellent slipperiness; the microcrystalline modified polyethylene wax has excellent chemical stability and can give the coating film better corrosion resistance.

[0015] The objective of the present invention is achieved through the following technical solutions: A method for preparing a waxy anticorrosive coating resistant to seawater corrosion, the method comprising the following preparation steps: First, add the emulsifier to deionized water, stir and mix for 10 minutes to obtain an emulsifier aqueous solution; add cardanol polyol and methacrylic acid to the emulsifier aqueous solution, emulsify for 40-50 minutes to obtain a base emulsion; add the initiator to water, stir and mix evenly to obtain an initiator solution; under the protection of a nitrogen atmosphere, drop the initiator solution into the base emulsion, adjust the temperature to 60-80°C, and stir in a water bath for 3-6 hours to obtain a water-soluble polymer; stir and mix the water-soluble polymer, aqueous fine oxidized polyethylene wax emulsion and metal aluminum powder filler evenly to obtain a coating.

[0016] The mixing ratio of the above-mentioned emulsifier aqueous solution, cardanol polyol and methacrylic acid is 100g:10-20g:5-10g, and the above-mentioned components constitute the base emulsion; the initiator is ammonium persulfate, and the mixing ratio of ammonium persulfate and deionized water is 0.1-1.0g:10g; the mixing ratio of the initiator solution and the base emulsion is 2-5g:100g.

[0017] In the method for preparing a waxy anti-corrosion coating resistant to seawater corrosion, the emulsifier in step (1) is octoxynol; wherein the mixing ratio of octoxynol to deionized water is 3-5g:100g.

[0018] The method for preparing a waxy anti-corrosion coating resistant to seawater corrosion comprises the following steps: the mass fraction of the water-soluble polymer in the waxy heavy anti-corrosion coating is 50-55%, the mass fraction of the wax emulsion in the anti-corrosion coating is 15-30%, and the mass fraction of the metal aluminum powder filler in the anti-corrosion coating is 5-15%.

[0019] The method for preparing a waxy anti-corrosion coating resistant to seawater corrosion comprises the wax emulsion having a mass fraction of 25% microcrystalline modified polyethylene wax.

[0020] In the method for preparing a waxy anti-corrosion coating resistant to seawater corrosion, the metal powder filler is aluminum powder of 10-500um.

[0021] The method for preparing a waxy anti-corrosion coating resistant to seawater corrosion comprises the following steps of coating the coating on a substrate, drying and curing the coating, wherein the drying temperature is 90°C and the drying time is 30 minutes, thereby obtaining a seawater-resistant waxy anti-corrosion coating.

[0022] The method for preparing a waxy anti-corrosion coating resistant to seawater corrosion comprises the following steps: the water-soluble polymer, aqueous fine oxidized polyethylene wax emulsion and metal aluminum powder filler are stirred and mixed at a stirring speed of 800 r / min for 40 minutes.

[0023] The advantages and effects of the present invention are: 1. The coating prepared by the present invention is wear-resistant, scratch-resistant and abrasion-resistant: the microcrystalline modified polyethylene wax is distributed in the coating film to protect the coating film, prevent scratches and abrasions, and provide damage resistance, thereby inhibiting the damage of waves, tides and currents to the equipment.

[0024] 2. The friction coefficient of the coating prepared by the present invention is controlled: the low friction coefficient of microcrystalline modified polyethylene wax is usually used to provide excellent slipperiness of the coating film. At the same time, due to different types of wax, it has a special silky soft touch, which reduces the direct or indirect acceleration of the corrosion process of equipment by marine microorganisms, attached organisms and their metabolites.

[0025] 3. Chemical resistance of the coating prepared by the present invention: Since the microcrystalline modified polyethylene wax has excellent chemical stability, it can give the coating film better water resistance, salt water spray resistance, and corrosion resistance to various chemical substances such as hydrochloric acid, phosphoric acid, formic acid, amines, sodium hydroxide, potassium hydroxide, etc. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the embodiments. Example 1

[0027] First, add 3g of the emulsifier octoxynol to 100g of deionized water, and stir and mix for 10 minutes to obtain an emulsifier aqueous solution. Add 13g of cardanol polyol and 6g of methacrylic acid to 103g of the emulsifier aqueous solution, and emulsify for 40-50min to obtain a base emulsion. Add 0.3g of initiator to 10g of deionized water, stir and mix evenly to obtain an initiator solution. Under the protection of a nitrogen atmosphere, add 10.3g of the initiator solution dropwise to 122g of the base emulsion, adjust the temperature to 60°C, and stir in a water bath for 6h to obtain a water-soluble polymer; Take 50g of the water-soluble polymer obtained in the previous step, then add 15g of 25% microcrystalline modified polyethylene wax emulsion and 5g of aluminum powder with a particle size of 10um. Stir the above substances in a container at a stirring speed of 800r / min for 40min. Then apply the obtained coating to the substrate and dry it at 90℃ for 30min to obtain a seawater wax-resistant heavy-duty anticorrosive coating. Example 2

[0028] First, add 5g of the emulsifier octoxynol to 100g of deionized water, and stir and mix for 10 minutes to obtain an emulsifier aqueous solution. Add 18g of cardanol polyol and 10g of methacrylic acid to 105g of the emulsifier aqueous solution, and emulsify for 40-50min to obtain a base emulsion. Add 0.5g of initiator to 10g of deionized water, stir and mix evenly to obtain an initiator solution. Under the protection of a nitrogen atmosphere, add 10.5g of the initiator solution dropwise to 133g of the base emulsion, adjust the temperature to 60°C, and stir in a water bath for 6h to obtain a water-soluble polymer; Take 50g of the water-soluble polymer obtained in the previous step, then add 17g of 25% microcrystalline modified polyethylene wax emulsion and 8g of aluminum powder with a particle size of 100um. Stir the above substances in a container at a stirring speed of 800r / min for 40min. Then apply the obtained coating to the substrate and dry it at 90℃ for 30min to obtain a seawater-resistant wax heavy-duty anticorrosive coating. Example 3

[0029] First, add 6g of the emulsifier octoxynol to 100g of deionized water, and stir and mix for 10 minutes to obtain an emulsifier aqueous solution. Add 20g of cardanol polyol and 10g of methacrylic acid to 106g of the emulsifier aqueous solution, and emulsify for 40-50min to obtain a base emulsion. Add 1.2g of initiator to 10g of deionized water, stir and mix evenly to obtain an initiator solution. Under the protection of a nitrogen atmosphere, add 11.2g of the initiator solution dropwise to 136g of the base emulsion, adjust the temperature to 60°C, and stir in a water bath for 6h to obtain a water-soluble polymer; Take 50g of the water-soluble polymer obtained in the previous step, then add 18g of 25% microcrystalline modified polyethylene wax emulsion and 8g of aluminum powder with a particle size of 200um. Stir the above substances in a container at a stirring speed of 800r / min for 40min. Then apply the obtained coating to the substrate and dry it at 90℃ for 30min to obtain a seawater-resistant wax heavy-duty anticorrosive coating.

[0030] The present invention illustrates the composition of the present invention by taking the above-mentioned implementation scheme as an example, but the present invention is not limited to the above-mentioned detailed composition. In other words, it does not mean that the present invention can only be implemented under the above-mentioned composition. Therefore, the equivalent replacement of raw materials and the addition of auxiliary agents and the selection of processing methods involved in the present invention should all be included in the scope of protection disclosure of the present invention.

Claims

1. A method for preparing a waxy anticorrosive coating resistant to seawater corrosion, characterized in that: The method comprises the following preparation steps: First, an emulsifier is added to deionized water, and the mixture is stirred for 10 minutes to obtain an emulsifier aqueous solution; cardanol polyol and methacrylic acid are added to the emulsifier aqueous solution, and the mixture is emulsified for 40-50 minutes to obtain a base emulsion; an initiator is added to water, and the mixture is stirred and mixed uniformly to obtain an initiator solution; under the protection of a nitrogen atmosphere, the initiator solution is added dropwise to the base emulsion, the temperature is adjusted to 60-80°C, and the mixture is stirred in a water bath for 3-6 hours to obtain a water-soluble polymer; the water-soluble polymer, an aqueous fine oxidized polyethylene wax emulsion and a metal aluminum powder filler are stirred and mixed uniformly to obtain a coating; the mixing ratio of the emulsifier aqueous solution, cardanol polyol and methacrylic acid is 100g:10-20g:5-10g, and the above components constitute the base emulsion; the initiator is ammonium persulfate, and the mixing ratio of ammonium persulfate to deionized water is 0.1-1.0g:10g; the mixing ratio of the initiator solution to the base emulsion is 2-5g:100g.

2. The method for preparing a waxy anticorrosive coating resistant to seawater corrosion according to claim 1, characterized in that: In the step (1), the emulsifier is octoxynil; wherein the mixing ratio of octoxynil to deionized water is 3-5g:100g.

3. The method for preparing a waxy anticorrosive coating resistant to seawater corrosion according to claim 1, characterized in that: The mass fraction of the water-soluble polymer in the waxy heavy anti-corrosion coating is 50-55%, the mass fraction of the wax emulsion in the anti-corrosion coating is 15-30%, and the mass fraction of the metal aluminum powder filler in the anti-corrosion coating is 5-15%.

4. The method for preparing a waxy anticorrosive coating resistant to seawater corrosion according to claim 3, characterized in that: The wax emulsion contains 25% microcrystalline modified polyethylene wax by mass.

5. The method for preparing a waxy anticorrosive coating resistant to seawater corrosion according to claim 3, characterized in that: The metal powder filler is aluminum powder with a particle size of 10-500 um.

6. The method for preparing a waxy anticorrosive coating resistant to seawater corrosion according to claim 1, characterized in that: The coating process of the coating is to coat the coating on the substrate, dry and solidify it, the drying temperature is 90° C., and the drying time is 30 minutes, so as to obtain the seawater wax resistant anticorrosive coating.

7. The method for preparing a waxy anticorrosive coating resistant to seawater corrosion according to claim 1, characterized in that: The water-soluble polymer, aqueous fine oxidized polyethylene wax emulsion and metal aluminum powder filler are stirred and mixed at a stirring speed of 800 r / min for 40 minutes.