Preparation method and application of environment-friendly active and passive double-effect synergistic modifier

Abstract

According to the preparation method and application of the environment-friendly active and passive double-effect synergistic modifier, an in-situ reaction compounding method is adopted, an intelligent nano controlled release technology is combined, and reduced graphene oxide obtained by reducing a natural product, a pH regulator, a slow release agent and a nano container are adopted to construct several environment-friendly active and passive double-effect synergistic modifiers in one step; meanwhile, the composite water-based coating can effectively delay permeation of corrosive particles in the early stage of use, and the passive blocking effect is achieved; the corrosion inhibitor can be released and a passive film can be formed when the coating is damaged in the later period of use, so that corrosion of a metal substrate is delayed; and an active and passive double-effect synergistic anti-corrosion effect is achieved, and the obtained anti-corrosion coating is excellent in anti-corrosion performance. After the coating is soaked for 90 days, the impedance modulus of the impedance modulus at 10mHz is within the range of 5 * 10 < 8 >-6 * 10 < 8 > omega.cm < 2 >, and the coating still has no falling, bubbling and rusting phenomena after being soaked in distilled water, sodium chloride, sulfuric acid and sodium hydroxide solutions for about 90 days.

Description

Technical Field

[0001] The invention relates to a preparation method and application of an environmentally friendly active and passive dual-effect synergistic modifier. Background Art

[0002] The VOCs emissions of traditional solvent-based paint products can cause great harm to human health and the environment. In order to accelerate the green transformation of development methods, green, low-carbon, and high-quality development will become an important direction for the development of coatings. Water-based paint uses water as a solvent or dispersion medium, is non-toxic, has a safe and environmentally friendly production process, and requires less equipment investment. It is one of the green coatings and has been widely used in the fields of construction, wood, metal, etc. However, it is less used in the field of heavy corrosion protection because its anti-corrosion performance in easily corrosive environments is still inferior to that of solvent-based paints. In order to improve the anticorrosion performance of waterborne coatings, various modifiers are introduced into waterborne polymer coating systems, such as CN111154392A, by adjusting the amount of silane coupling agent added to modify nano-silica to regulate the dispersibility of graphene oxide (GO) in waterborne coatings, a modified GO composite waterborne polyurethane environmentally friendly anticorrosive coating is prepared, due to the two-dimensional barrier effect of GO, that is, passive barrier effect, greatly improve the anticorrosion performance of waterborne polyurethane, after two months of immersion in 3.5% NaCl solution, no rust appears on the surface, which is of great significance to the improvement of the anticorrosion performance of waterborne coatings. However, due to the presence of oxidized groups, the anticorrosion modification effect of GO is not as good as that of reduced graphene oxide (rGO). However, rGO is difficult to disperse in water due to the disappearance of a large number of π-π stacking and surface polar groups, and has poor compatibility with waterborne coatings. In addition, there is currently a part of the technology that adds corrosion inhibitors to the coating, and quickly self-repairs when the coating is damaged, that is, active anticorrosion, to improve the anticorrosion performance of waterborne coatings. However, after searching, there are few reports on patents related to water-based coatings with active and passive dual protective effects, and the environmental protection and step simplification in the preparation process of the modifier have not been fully considered. Therefore, the field urgently needs to study and design a dual-effect synergistic modifier with simple preparation steps, environmentally friendly preparation process, good compatibility with water-based coatings, and active and passive anti-corrosion effects, so as to achieve high performance and long-term anti-corrosion effect of green water-based coatings. Summary of the invention

[0003] In view of the above deficiencies in the prior art, the present invention provides a preparation method and application of an environmentally friendly active and passive dual-effect synergistic modifier.

[0004] The present invention uses an in-situ reaction composite method, combined with intelligent nano controlled release technology, and uses rGO, pH regulator, slow release agent, and nano container (or nano container precursor) obtained by natural product reduction to construct several environmentally friendly active and passive dual-effect synergistic modifiers in one step. The hydroxyl group in the natural product reduces the oxygen-containing hydrophilic functional groups on the surface of GO, avoiding the reduction of the anti-corrosion performance of the coating due to the decrease in hydrophobicity. The aromatic structural units in the natural product can be adsorbed on the surface of rGO and form π-π interactions, which play a stabilizing role, thereby avoiding the agglomeration of rGO and regulating the compatibility of rGO with water-based coatings. The natural product adsorbed on the surface of rGO is used to provide affinity sites, nano container (precursor) is added to the system, and effectively composited with rGO. The solubilization and loading of the corrosion inhibitor in the nano container are realized by hydrophobic micro-regions. The positive charge carried by the nano container is electrostatically adsorbed with rGO, thereby realizing the synergy of active and passive anti-corrosion. The modifier can be directly blended with water-based coatings and significantly enhance the anti-corrosion and self-healing properties of the coatings. After 90 days of immersion, the impedance modulus at 10 mHz is 5×10 8 ~6×10 8 Ω·cm 2 The impedance modulus of the coating without adding modifier decreased to 10 8 Ω·cm 2 In terms of chemical resistance, the coating with modifier performs better than the coating without modifier, and there is no shedding, blistering or rusting after being immersed in 3.5% NaCl solution for about 90 days.

[0005] The purpose of the present invention is to provide a preparation method and application of an environmentally friendly active and passive dual-effect synergistic modifier, which has good compatibility with water-based coatings, the reagents used in the preparation process all meet environmental protection requirements, the preparation steps are simple, and the loading step of the corrosion inhibitor is avoided. When used for the modification of water-based anticorrosive coatings, it can effectively delay the penetration of corrosive particles in the early stage of service and play a passive barrier role; when the coating is damaged in the later stage of service, the corrosion inhibitor can be released and a passivation film can be formed to delay the corrosion of the metal substrate; it has an active-passive dual-effect synergistic anticorrosion effect, and the obtained anticorrosion coating has excellent corrosion resistance.

[0006] A method for preparing an environmentally friendly active and passive dual-effect synergistic modifier comprises the following steps:

[0007] 1) dispersing a certain mass of graphene oxide powder in water, ultrasonically mixing, adjusting the pH value to a suitable value by a pH regulator, passing nitrogen, adding a natural reducing agent, heating the reaction at a temperature range of 80-100° C., preferably 95° C., reacting for 10-14 hours, preferably 12 hours, to obtain reduced graphene oxide;

[0008] 2) dialyzing the dispersion obtained after the reaction with a dialysis bag for two weeks, then adding an appropriate amount of nanocontainer (nanocontainer precursor) and a corrosion inhibitor to the dialyzed dispersion, and heating the dispersion for reaction at a temperature range of 70-90° C., preferably 80° C., for 1-5 hours;

[0009] 3) The dispersion obtained after the reaction is centrifuged and washed to obtain an environmentally friendly active and passive dual-effect synergistic modifier dispersion, and then dried to obtain pure environmentally friendly active and passive dual-effect synergistic modifier powder.

[0010] As a preferred technical solution, the natural reducing agent is one or more of plant extracts such as rose, ginkgo leaf, caffeic acid, sodium citrate, tannic acid, rutin, gallic acid, and L-lysine, preferably one or more of tannic acid and rutin, and the added mass is 3-8 times the mass of graphene oxide.

[0011] As a preferred technical solution, the nanocontainer and its precursor are one or more of halloysite nanotubes, silsesquioxane (POSS), MOFs with a zeolite framework structure, and tetraethyl orthosilicate, and the added mass is 0.7-2 times the mass of reduced graphene oxide.

[0012] As a preferred technical solution, the corrosion inhibitor is one or more of benzotriazole (BTA), L-histidine, p-coumaric acid (CA), phytic acid, benzenesulfonic acid and their derivatives.

[0013] As a preferred technical solution, the washing liquid is one or more of ethanol and deionized water, and the drying temperature after washing is 60-100°C, preferably 80°C.

[0014] The environmentally friendly active and passive dual-effect synergistic modifier prepared by the invention can be used to prepare an environmentally friendly active and passive dual-effect synergistic modifier / polymer emulsion composite water-based anticorrosive coating.

[0015] An environmentally friendly active and passive dual-effect synergistic modifier / polymer emulsion composite water-based anticorrosive coating comprises the active and passive dual-effect synergistic modifier of the present invention. During long-term use, the coating not only has a barrier effect in the initial stage of coating immersion, but also can provide excellent passive protection. The coating can also release corrosion inhibitor molecules to form a passivation film in the later stage of coating immersion, that is, when corrosion particles reach the metal surface to cause metal corrosion, thereby providing excellent active protection.

[0016] As a preferred technical solution, the polymer emulsion is one or a mixture of water-based polyacrylate emulsion, water-based epoxy resin emulsion, and water-based polyacrylate epoxy composite emulsion, preferably water-based polyacrylate epoxy composite emulsion.

[0017] As a preferred technical solution, a method for preparing an environmentally friendly active and passive dual-effect synergistic modifier / polymer emulsion composite water-based anti-corrosion coating is a simple blending method, and the preparation steps include the following:

[0018] 1) Add 0.5%-1% by weight of the dry coating film of the environmentally friendly active and passive dual-effect synergistic modifier to water and mix it by ultrasonic; or directly replace it with a dispersion of the environmentally friendly active and passive dual-effect synergistic modifier containing an equal amount of solids;

[0019] 2) adding the dispersion in step 1) to the polymer emulsion under the action of a high-speed stirrer, the rotation speed is preferably 500-700 rpm, and the solid content of the polymer emulsion is preferably 20%-40%, to obtain a composite emulsion;

[0020] 3) adding 0.3-0.5 parts by mass of leveling agent, 0.1-1 parts by mass of defoaming agent, 3-6 parts by mass of film-forming aid, 0.1-0.3 parts by mass of thickener and 1.3-1.6 parts by mass of ADH or water-based epoxy curing agent (according to the ratio of epoxy equivalent to active hydrogen equivalent of 1:1 to 1:1.2) to the composite emulsion obtained in step 2) under high-speed stirring per 100 parts by mass of the composite emulsion.

[0021] The beneficial effects of the present invention are as follows: through the composition and structural design of the modifier and the exploration of the preparation method, the limitations of general modifiers for passive corrosion protection alone or active corrosion protection alone are broken through, and the preparation process is simple and environmentally friendly, the product has excellent dispersibility, and can be stably dispersed in the polymer emulsion for more than half a year, thereby achieving the simultaneous improvement of the controlled release of the corrosion inhibitor, barrier performance, and compatibility; the composite coating prepared by the environmentally friendly active and passive dual-effect synergistic modifier has achieved a new breakthrough in the coating matrix and the anti-corrosion mechanism, and the corrosion resistance of the water-based composite coating has been greatly improved. After being immersed in acid, alkali, salt, and distilled water for 90 days, there is still no shedding, blistering, or rusting, thereby achieving the simultaneous improvement of the environmental protection and anti-corrosion performance of the coating. DETAILED DESCRIPTION

[0022] The following examples are provided to further illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] Example 1: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0024] 1. Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier;

[0025] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 10 g of rutin, raise the temperature to 95 ° C, react for 12 hours, and obtain reduced graphene oxide;

[0026] B. The dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 1.5 g TEOS and 0.5 g BTA were added to the dialyzed dispersion, heated to 80° C., and reacted for 2 hours;

[0027] C. Add water to the dispersion obtained after the reaction, centrifuge and wash, and dry at 80° C. to obtain a pure environmentally friendly active and passive dual-effect synergistic modifier solid.

[0028] 2. Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0029] A. Add 0.5g of environmentally friendly active and passive dual-effect synergistic modifier solid to 20ml of water and mix by ultrasonic to obtain an environmentally friendly active and passive dual-effect synergistic modifier dispersion; or directly replace it with an environmentally friendly active and passive dual-effect synergistic modifier dispersion containing an equal amount of solid.

[0030] B. Add the dispersion prepared in step a to 100 g of waterborne polyacrylate epoxy composite emulsion while stirring at a speed of 500 rpm. After uniform dispersion, increase the speed to 1500-3000 rpm, and add 0.5 g BYK333, 0.5 g BYK024, 4 g DPNB, 0.5 g BYK428 and 13 g HGF-100 in sequence to prepare a composite waterborne anticorrosive coating.

[0031] Example 2: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0032] 1. Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0033] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 15 g of tannic acid, heat to 90° C., react for 8 hours to obtain reduced graphene oxide; the other subsequent steps are the same as those in Example 1.

[0034] Example 3: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0035] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0036] 2 g of graphene oxide powder was dispersed in water, ultrasonically mixed, the pH was adjusted to 12, nitrogen was passed, 15 g of tannic acid was added, the temperature was raised to 90° C., and the reaction was carried out for 8 hours to obtain reduced graphene oxide; the dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 2 g of HNTs and 4 g of L-His were added to the dialyzed dispersion, heated to 90° C., and reacted for 5 hours; the other subsequent steps were the same as those in Example 1.

[0037] Example 4: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0038] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0039] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 15 g of gallic acid, raise the temperature to 95° C., react for 6 hours, and obtain reduced graphene oxide.

[0040] B. The dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 2g HNTs and 4g BTA were added to the dialyzed dispersion, heated to 90°C, and reacted for 5 hours;

[0041] The other subsequent steps are the same as those in Example 1.

[0042] Example 5: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0043] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0044] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 15 g of gallic acid, raise the temperature to 95° C., react for 6 hours, and obtain reduced graphene oxide.

[0045] B. The dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 1.5 g TEOS and 0.5 g BTA were added to the dialyzed dispersion, heated to 80° C., and reacted for 2 hours;

[0046] The other subsequent steps are the same as those in Example 1.

[0047] Example 6: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0048] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0049] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 10 g of rutin, raise the temperature to 95 ° C, react for 12 hours, and obtain reduced graphene oxide;

[0050] B. The dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 2 g POSS and 1 g BTA were added to the dialyzed dispersion, heated to 80° C., and reacted for 3 hours;

[0051] The other subsequent steps are the same as those in Example 1.

[0052] Example 7: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0053] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0054] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 10 g of rutin, raise the temperature to 95 ° C, react for 12 hours, and obtain reduced graphene oxide;

[0055] B. The dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 2g MOFs and 1g BTA were added to the dialyzed dispersion, heated to 80°C, and reacted for 3 hours;

[0056] The other subsequent steps are the same as those in Example 1.

[0057] Example 8: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0058] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0059] A. Disperse 2 g of graphene oxide powder in water, mix by ultrasonication, adjust the pH to 12, pass nitrogen, add 10 g of rutin, raise the temperature to 95 ° C, react for 12 hours, and obtain reduced graphene oxide;

[0060] B. The dispersion obtained after the reaction was dialyzed with a dialysis bag for two weeks, and then 1.5 g TEOS and 1 g CA were added to the dialyzed dispersion, heated to 80° C., and reacted for 2 hours;

[0061] The other subsequent steps are the same as those in Example 1.

[0062] Example 9: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0063] Preparation steps of the environmentally friendly active and passive dual-effect synergistic modifier: replace 1.5g TEOS in A in Example 1 with 3g TEOS, and the subsequent other steps are the same as Example 1.

[0064] Example 10: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate epoxy composite water-based anticorrosive coating;

[0065] Preparation steps of environmentally friendly active and passive dual-effect synergistic modifier:

[0066] The 2 g HNTs in step A of Example 3 were replaced with 4 g TEOS; the other subsequent steps were the same as those in Example 3.

[0067] Example 11: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / polyacrylate composite water-based anticorrosive coating;

[0068] The aqueous polyacrylate epoxy composite emulsion used in step B of Example 1 was replaced with an aqueous polyacrylate emulsion, 13 g of HGF-100 was replaced with 1.5 g of ADH, and the other subsequent steps were the same as those in Example 1.

[0069] Example 12: Preparation of environmentally friendly active and passive dual-effect synergistic modifier / epoxy resin composite water-based anti-corrosion coating;

[0070] The aqueous polyacrylate epoxy composite emulsion used in step B in Example 1 was replaced with an aqueous epoxy resin emulsion, and the other subsequent steps were the same as in Example 1.

[0071] Example 13: Preparation steps of waterborne polyacrylate epoxy composite anticorrosive coating;

[0072] Under high-speed stirring, 0.5 g BYK333, 0.5 g BYK024, 4 g DPNB, 1.5 g BYK428 and 13 g HGF-100 were added to 100 g of water-based polyacrylate epoxy composite emulsion to obtain a composite coating.

[0073] Example 14: Preparation of waterborne epoxy resin anticorrosive coating;

[0074] The aqueous polyacrylate epoxy composite emulsion was replaced with an aqueous epoxy resin emulsion, and the other subsequent steps were the same as those in Example 13.

[0075] Example 15: Preparation of waterborne polyacrylate anticorrosive coating;

[0076] The aqueous polyacrylate epoxy composite emulsion was replaced with an aqueous polyacrylate emulsion, and the other subsequent steps were the same as those in Example 13.

[0077] The various properties of the coatings obtained from the anti-corrosion coatings of Examples 1-15 (Examples 13-15 are comparative examples) are shown in Table 1.

[0078] Table 1 Example measurement results

[0079]

[0080]

[0081] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope defined in the claims.

Claims

1. A method for preparing an environmentally friendly active and passive dual-effect synergistic modifier, characterized in that: The steps include: 1) dispersing a certain mass of graphene oxide powder in water, ultrasonically mixing, adjusting the pH value to a suitable value by a pH regulator, passing nitrogen, adding a natural reducing agent, heating the reaction at a temperature range of 80-100° C., reacting for 10-14 hours, and obtaining a reduced graphene oxide dispersion; 2) dialyzing the dispersion obtained after the above reaction with a dialysis bag for two weeks, then adding an appropriate amount of nanocontainer and corrosion inhibitor to the dialyzed dispersion, and heating the reaction at a temperature range of 70-90° C. for 1-5 hours; 3) The dispersion obtained after the reaction is centrifuged and washed to obtain an environmentally friendly active and passive dual-effect synergistic modifier dispersion, and finally dried to obtain a pure environmentally friendly active and passive dual-effect synergistic modifier powder.

2. The method for preparing an environmentally friendly active and passive dual-effect synergistic modifier according to claim 1, characterized in that: The natural reducing agent is one or more of plant extracts such as rose, ginkgo leaf, caffeic acid, sodium citrate, tannic acid, rutin, gallic acid, and L-lysine, and the added mass is 3-8 times the mass of graphene oxide powder.

3. The method for preparing an environmentally friendly active and passive dual-effect synergistic modifier according to claim 1, characterized in that: The nano container is one or more of halloysite nanotubes, silsesquioxane, MOFs with a zeolite framework structure, and tetraethyl orthosilicate, and the added mass is 0.7-2 times the mass of the reduced graphene oxide dispersion.

4. The method for preparing an environmentally friendly active and passive dual-effect synergistic modifier according to claim 1, characterized in that: The corrosion inhibitor is one or more of benzotriazole, L-histidine, p-coumaric acid, phytic acid, benzenesulfonic acid and derivatives thereof.

5. The method for preparing an environmentally friendly active and passive dual-effect synergistic modifier according to claim 1, characterized in that: In step 3), the washing liquid is one or more of ethanol and deionized water, and the drying temperature is 60-100°C.

6. An environmentally friendly active and passive dual-effect synergistic modifier prepared according to any one of claims 1 to 5.

7. Use of the environmentally friendly active and passive dual-effect synergistic modifier prepared by the method of any one of claims 1 to 5 to prepare an environmentally friendly active and passive dual-effect synergistic modifier / polymer emulsion composite water-based anticorrosive coating.

8. A method for preparing an environmentally friendly active and passive dual-effect synergistic modifier / polymer emulsion composite water-based anticorrosive coating using the environmentally friendly active and passive dual-effect synergistic modifier prepared by the method of any one of claims 1 to 5, characterized in that: The preparation steps are as follows: 1) Add 0.5%-1% by weight of the dry coating film of the environmentally friendly active and passive dual-effect synergistic modifier to water and mix it by ultrasonic; or directly replace it with a dispersion of the environmentally friendly active and passive dual-effect synergistic modifier containing an equal amount of solids; 2) adding the dispersion in step 1) to the polymer emulsion under the action of a high-speed stirrer, the rotation speed is preferably 500-700 rpm, and the solid content of the polymer emulsion is preferably 20%-40%, to obtain a composite emulsion; 3) adding 0.3-0.5 parts by mass of leveling agent, 0.1-1 parts by mass of defoaming agent, 3-6 parts by mass of film-forming aid, 0.1-0.3 parts by mass of thickener and 1.3-1.6 parts by mass of ADH or waterborne epoxy curing agent to every 100 parts by mass of the composite emulsion obtained in step 2) under high-speed stirring.

9. The method according to claim 8, characterized in that The polymer emulsion is one or a mixture of water-based polyacrylate emulsion, water-based epoxy resin emulsion, and water-based polyacrylate epoxy composite emulsion.

10. The composite water-based anticorrosive coating prepared according to the method of claim 8 or 9.

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