Water-based paint for multi-material adhesion of engines and preparation method thereof

Abstract

The present invention relates to the technical field of water-based anti-corrosion coatings, and proposes a water-based paint for multi-material adhesion of engines and a preparation method thereof. The water-based paint comprises a water-based acrylic emulsion, a sanding slurry containing zinc phosphate and nano-magnesium silicate, a pre-coated calcium ion resin, and an additive; the pre-coated calcium ion resin is composed of a sulfonic acid cation exchange resin loaded with Ca 2+ After that, it is coated with polyvinyl pyrrolidone layer, and then coated with acrylic acid to form an acrylic coating layer. When the corrosive medium penetrates into the substrate, the acrylic coating layer + Under the action of swell to form pores, releasing Ca 2+ , with zinc phosphate PO4 3－ This solution utilizes acrylic-coated calcium ion resin to achieve self-healing, while zinc phosphate and nano-magnesium silicate form a dense barrier. This solution addresses the problem of traditional coatings failing to self-repair after damage, leading to the spread of corrosion. It effectively adheres to various engine components and provides long-lasting corrosion protection.

Description

Technical Field

[0001] The present application relates to the technical field of water-based paints, and in particular to a water-based paint for multi-material adhesion of engines and a preparation method thereof. Background Art

[0002] With increasingly stringent environmental regulations, water-based anti-corrosion coatings are a key alternative to traditional solvent-based coatings. Initially, these technologies used chromates as the primary corrosion inhibitor, which has since been banned due to its high toxicity. Subsequently, zinc phosphate was used as the primary corrosion inhibitor, introduced through physical doping. This resulted in both initial burst release and later failure. High zinc content also reduced coating toughness and susceptibility to hydrogen-induced blistering. Furthermore, hydrolysis of zinc powder oxidation products in humid environments exacerbated coating flaking. Recent research has focused on self-healing coatings, incorporating technologies such as microencapsulation to achieve single-shot repairs by encapsulating corrosion inhibitors. However, excessive encapsulation can compromise coating density. While light-transmitting / thermal-responsive smart coatings can achieve multiple repairs, they require continuous external energy input, making them unsuitable for temperature fluctuations during engine start-stop conditions and the lack of light in enclosed structures. These coatings often suffer from delayed repair responses and passive triggering mechanisms. Traditional filler systems often employ a single particle size, making it difficult to construct a dense physical barrier. Micron-sized zinc phosphates can provide cathodic protection but are prone to forming microporous defects. Nanofillers, while capable of filling voids, tend to aggregate and deactivate.

[0003] The Chinese patent with the authorization announcement number CN110452600B discloses a self-repairing heavy-duty anti-corrosion coating and its preparation method. Through the parallel, directional and overlapping arrangement of glass flakes, a barrier is formed to the corrosive medium, which effectively increases the penetration path of corrosive media such as water, oxygen, and ions, and improves the anti-corrosion performance. The self-repairing microcapsules are porous particles loaded with repair reagents. The repair reagents in the coating around the tiny damage will be released from the porous particles to prevent the further occurrence and spread of corrosion. However, the repair reagents used are organic reagents. They are physically loaded through porous particles and need to be passively released after the coating is damaged. The repair response is delayed, and the photothermal triggering mechanism is not applicable in a closed engine environment. The organic repair reagents may fail due to the influence of high temperature and are not suitable for engine operating conditions. Summary of the Invention

[0004] In order to solve the problem that traditional anti-corrosion coatings cannot self-repair in time after the coating is damaged, which leads to the spread of corrosion, this application provides a water-based paint for engine multi-material adhesion and its preparation method. The water-based paint includes a water-based acrylic emulsion, a sanding slurry containing zinc phosphate and nano-magnesium silicate, a pre-coated calcium ion resin and an additive; the pre-coated calcium ion resin is composed of a sulfonic acid cation exchange resin loaded with Ca 2+ After that, it is coated with polyvinyl pyrrolidone layer and then coated with acrylic acid to form an acrylic coating layer. When the corrosive medium penetrates into the metal interface, the acrylic coating layer +Under the action of swell to form pores, releasing Ca 2+ , with zinc phosphate PO4 3- This solution utilizes acrylic-coated calcium ion resin to achieve self-repair, while zinc phosphate and nano-magnesium silicate form a dense barrier. This solution addresses the problem of traditional anti-corrosion coatings failing to self-repair after damage, leading to the spread of corrosion. It effectively adheres to various engine components and provides long-lasting corrosion protection.

[0005] To achieve the above objectives, this application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a water-based paint for multi-material adhesion of an engine, comprising:

[0007] Water-based acrylic emulsion, sanding slurry, pre-coated calcium ion resin and additives;

[0008] The sand grinding slurry contains zinc phosphate and nano magnesium silicate; the pre-coated calcium ion resin is obtained by loading calcium ions on a sulfonic acid type cation exchange resin and then treating it with polyvinyl pyrrolidone.

[0009] In a feasible implementation situation, the sulfonic acid type cation exchange resin is H + type, with an exchange capacity of ≥4.8mmol / g; the particle size of the nano magnesium silicate is 20-50nm.

[0010] In a feasible implementation, the mass ratio of the aqueous acrylic emulsion, the sanding slurry, the pre-coated calcium ion resin and the additive is (50-55):(30-44):(5-8):(2-5).

[0011] In a feasible implementation, the auxiliary agent includes nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and hydroxyethyl cellulose aqueous solution in a mass ratio of (0.5-1): (0.2-0.5): (0.5-1.0): (2-3); the nano-cerium oxide particle size is 20-50 nm.

[0012] In a second aspect, the present application provides a method for preparing a water-based paint for multi-material adhesion of an engine, comprising the following steps:

[0013] S1, pre-treating the cation exchange resin, then loading it with calcium ions, adding polyvinyl pyrrolidone, mixing and granulating, and drying to obtain a pre-coated calcium ion resin;

[0014] S2, mixing zinc phosphate and nano magnesium silicate and grinding them to obtain a sand grinding slurry;

[0015] S3. After adding the sand-milled slurry to the water-based acrylic emulsion, add the additives and the pre-coated calcium ion resin, stir evenly, add deionized water to a solid content of 40%-45%, and obtain a water-based paint; filter through a vibrating screen, and store in a nitrogen atmosphere to obtain the water-based paint for multi-material adhesion of the engine.

[0016] In a feasible implementation scenario, the preparation method of the pre-coated calcium ion resin in S1 is specifically as follows:

[0017] The cation exchange resin is soaked in deionized water until it swells, then loaded into a glass column, and hydrochloric acid solution is added to rinse until the pH of the effluent is within the range of 5-6, and then vacuum filtered to a water content of 40% to 50% to obtain a pretreated resin;

[0018] The pretreated resin is reacted with a calcium chloride solution at a mass ratio of 1:(6-8), and washed until no chloride ions remain to obtain a calcium ion loaded resin;

[0019] The calcium ion loaded resin and the polyvinyl pyrrolidone solution are mixed in a mass ratio of (8-10):1, granulated, sieved into 40-60 mesh particles, and vacuum dried to a moisture content of less than 3% to obtain a pre-coated calcium ion resin.

[0020] In a feasible implementation scenario, the preparation of the sand grinding slurry in S2 also includes: mixing deionized water, sodium polyacrylate, and polydimethylsiloxane, adjusting the pH to 8.5-9.0, and then adding zinc phosphate and nano-magnesium silicate; after stirring, passing through a 300-mesh sieve, performing the grinding treatment, and after the grinding treatment, passing through an 800-mesh sieve to obtain the sand grinding slurry; the mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate and nano-magnesium silicate is 50:(0.5-1.0):(0.1-0.3):(5-8):(3-5).

[0021] In a feasible implementation, the molecular weight of the sodium polyacrylate is 7000-8000 g / mol; and the viscosity of the polydimethylsiloxane is 280-300 cSt.

[0022] In a feasible implementation scenario, the preparation method of the aqueous acrylic emulsion described in S3 is: mixing butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate and water, and pre-emulsifying them by high-speed shearing to form a monomer emulsion; adding the monomer emulsion dropwise to an ammonium persulfate solution, and filtering through a sieve to obtain the aqueous acrylic emulsion.

[0023] In a feasible implementation scenario, after adding deionized water in S3, filtration and nitrogen-filled storage must be completed within 30 minutes, and the storage temperature is ≤30°C.

[0024] Beneficial technical effects:

[0025] This scheme uses ion exchange resin to preload Ca 2+ , pre-coated with a polyvinyl pyrrolidone layer, and then coated with acrylic acid to form an acrylic coating. When the coating is damaged and the corrosive medium penetrates into the metal interface, the acrylic coating is protonated in an acidic environment, the molecular chain segments swell, and pores are formed on the resin surface. + Enter the resin through the pores and interact with the Ca 2+ Competitive ion exchange occurs, and the released Ca 2+ Ca is released through the pores and diffuses to the interface. 2+ PO4 produced by dissolution of zinc phosphate 3- A hydroxyapatite repair layer is generated to achieve a self-repair response and prevent the spread of corrosion. At the same time, a dense protective paint layer is formed by compounding a core-shell structure coated with resin and acrylic acid with a composite filler of micron-sized zinc phosphate and nano-magnesium silicate, achieving a corrosion-resistant effect and improving durability. The water-based paint prepared by the present invention can effectively adhere to the multi-material parts of the engine. At a low zinc content, the chemical energy of corrosion is converted into a repair driving force, thereby improving the repair efficiency and extending the corrosion life. This solves the problem that traditional anti-corrosion coatings cannot self-repair in time after the coating is damaged and corroded, resulting in the spread of corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the preparation method of the water-based paint for multi-material adhesion of engines according to the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions, and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the following examples. However, this should not be construed as limiting the scope of this application to the following examples. Without departing from the above-mentioned method concepts of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0028] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to be limiting of the application.

[0029] As used in this application, the singular forms "for," "or," "an," "any," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0030] In addition, the terms “first” and “second”, if used, are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0031] In a first aspect, the present application provides a water-based paint for multi-material adhesion of an engine, comprising:

[0032] Water-based acrylic emulsion, sanding slurry, pre-coated calcium ion resin and additives;

[0033] The sand grinding slurry contains zinc phosphate and nano magnesium silicate; the pre-coated calcium ion resin is obtained by loading calcium ions on a sulfonic acid type cation exchange resin and then treating it with polyvinyl pyrrolidone.

[0034] In a feasible implementation situation, the sulfonic acid type cation exchange resin is H + type, with an exchange capacity of ≥4.8mmol / g; the particle size of the nano magnesium silicate is 20-50nm.

[0035] In a feasible implementation, the mass ratio of the aqueous acrylic emulsion, the sanding slurry, the pre-coated calcium ion resin and the additive is (50-55):(30-44):(5-8):(2-5).

[0036] In a feasible implementation, the auxiliary agent includes nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and hydroxyethyl cellulose aqueous solution in a mass ratio of (0.5-1): (0.2-0.5): (0.5-1.0): (2-3); the nano-cerium oxide particle size is 20-50 nm.

[0037] Water-based acrylic emulsion is used as a film-forming substance and is compounded with sanding slurry. Acrylic resin provides flexibility and adhesion, while sanding slurry enhances mechanical strength and corrosion resistance. A solid content of 45% optimizes coating leveling and avoids cracking or shrinkage. Nano-cerium oxide is added to consume O2 and H in the corrosive medium. + , slowing down the corrosion rate of the metal substrate; the leveling agent BYK-346 can reduce the surface energy of the coating, enhance hydrophobicity, reduce water molecule penetration, and inhibit Cl - Diffusion; adipic acid dihydrazide acts as a crosslinker, reacting with the carboxyl groups of the acrylic emulsion to form a crosslinked network structure, improving the coating's hardness and impact resistance; an aqueous solution of ethyl cellulose acts as a thickener, adjusting the coating's rheology, preventing filler settling, and ensuring uniform application. The resulting water-based paint is passed through a 200-mesh vibrating screen to remove impurities and then stored in a nitrogen-filled atmosphere to extend the coating's storage stability and prevent premature resin activation.

[0038] In a second aspect, the present application provides a method for preparing a water-based paint for multi-material adhesion of an engine, comprising the following steps:

[0039] S1, pre-treating the cation exchange resin, then loading it with calcium ions, adding polyvinyl pyrrolidone, mixing and granulating, and drying to obtain a pre-coated calcium ion resin;

[0040] S2, mixing zinc phosphate and nano magnesium silicate and grinding them to obtain a sand grinding slurry;

[0041] S3. After adding the sand-milled slurry to the water-based acrylic emulsion, add the additives and the pre-coated calcium ion resin, stir evenly, add deionized water to a solid content of 40%-45%, and obtain a water-based paint; filter through a vibrating screen, and store in a nitrogen atmosphere to obtain the water-based paint for multi-material adhesion of the engine.

[0042] Ion exchange resin preloaded with Ca 2+ , a polyvinyl pyrrolidone layer is covered on the resin surface, and then coated with acrylic acid to form an acrylic coating layer, which forms a physical barrier under normal conditions to prevent the resin from directly contacting the aqueous medium in the coating, avoiding Ca 2+ Release in advance; in corrosive media (such as Cl - , H2O, O2) penetrate into the metal interface, the metal substrate begins to undergo an anodic reaction (Fe→Fe 2+ +2e - ), the cathode reaction generates H + (2H + +2e - →H2↑). H in the local microenvironment + The acrylic coating layer is protonated in an acidic environment, the molecular chain segments swell, and nano-scale pores are formed on the resin surface. + Enter the resin through the pores and interact with the Ca 2+ Competitive ion exchange occurs, and the released Ca 2+ Ca is released through the pores and diffuses to the interface. 2+ PO4 produced by dissolution of zinc phosphate 3- A hydroxyapatite repair layer is generated to achieve self-repair response. At the same time, a dense protective paint layer is formed by compounding the core-shell structure coated with resin and acrylic acid with the composite fillers of micron-sized zinc phosphate and nano-magnesium silicate to achieve corrosion resistance and improve durability. The chemical energy released by the corrosion reaction provides the driving force for ion exchange, and no external energy input of Ca is required. 2+ The release position is precisely limited to the corrosion area to avoid waste of resources.

[0043] In a feasible implementation scenario, the preparation method of the pre-coated calcium ion resin in S1 is specifically as follows:

[0044] The cation exchange resin is soaked in deionized water until it swells, then loaded into a glass column, and hydrochloric acid solution is added to rinse until the pH of the effluent is within the range of 5-6, and then vacuum filtered to a water content of 40% to 50% to obtain a pretreated resin;

[0045] The pretreated resin is reacted with a calcium chloride solution at a mass ratio of 1:(6-8), and washed until no chloride ions remain to obtain a calcium ion loaded resin;

[0046] The calcium ion loaded resin and the polyvinyl pyrrolidone solution are mixed in a mass ratio of (8-10):1, granulated, sieved into 40-60 mesh particles, and vacuum dried to a moisture content of less than 3% to obtain a pre-coated calcium ion resin.

[0047] First, the sulfonic acid type cation exchange resin is pretreated and the resin is converted into H + type, activate the sulfonic acid group (-SO3H), enhance the ion exchange capacity, improve the calcium ion loading efficiency, and promote the full progress of the subsequent ion exchange reaction; then the resin reacts with calcium chloride solution, H + Ca 2+ The polyvinyl pyrrolidone solution acts as a binder, promoting uniform granulation of the resin particles. Its long-chain structure prevents resin agglomeration through steric hindrance. The polyvinyl pyrrolidone molecular chain contains a large number of polar amide groups (-NC=O), which can form hydrogen bonds with the carboxylic acid groups in the acrylic emulsion, enhancing the interfacial bonding between the two and promoting uniform mixing of the polyvinyl pyrrolidone and acrylic acid. The polyvinyl pyrrolidone layer acts as an intermediate transition layer, further combining with the water-based acrylic emulsion to form a core-shell structure with the resin as the core and the acrylic composite layer as the shell.

[0048] In a feasible implementation scenario, the preparation of the sand grinding slurry in S2 also includes: mixing deionized water, sodium polyacrylate, and polydimethylsiloxane, adjusting the pH to 8.5-9.0, and then adding zinc phosphate and nano-magnesium silicate; after stirring, passing through a 300-mesh sieve, performing the grinding treatment, and after the grinding treatment, passing through an 800-mesh sieve to obtain the sand grinding slurry; the mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate and nano-magnesium silicate is 50:(0.5-1.0):(0.1-0.3):(5-8):(3-5).

[0049] Zinc phosphate is compounded with nano-magnesium silicate, and sodium polyacrylate dispersant and polydimethylsiloxane wetting agents are added to form a stable suspension system. Zinc phosphate provides anodic protection and passivates the metal substrate surface. Nano-magnesium silicate fills the coating's micropores and hydrolyzes to generate colloidal silicic acid, blocking the diffusion path of the corrosive medium. Sodium polyacrylate acts as a dispersant, preventing zinc phosphate and magnesium silicate from agglomerating and improving slurry uniformity. Polydimethylsiloxane acts as a wetting agent, reducing surface tension and enhancing the bond between the filler and the substrate. 2-Amino-2-methyl-1-propanol is used to adjust the pH to 8.5-9.0 and stabilize the premix system. The premix is then ground to improve filler dispersion and reduce coating micro-defects. Nano-magnesium silicate is evenly embedded in the gaps between the zinc phosphate, forming a dense physical barrier.

[0050] In a feasible implementation, the molecular weight of the sodium polyacrylate is 7000-8000 g / mol; and the viscosity of the polydimethylsiloxane is 280-300 cSt.

[0051] In a feasible implementation scenario, the preparation method of the aqueous acrylic emulsion described in S3 is: mixing butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate and water, and pre-emulsifying them by high-speed shearing to form a monomer emulsion; adding the monomer emulsion dropwise to an ammonium persulfate solution, and filtering through a sieve to obtain the aqueous acrylic emulsion.

[0052] In a feasible implementation scenario, after adding deionized water in S3, filtration and nitrogen-filled storage must be completed within 30 minutes, and the storage temperature is ≤30°C.

[0053] The following will describe in detail a water-based paint for multi-material adhesion of engines and a preparation method thereof provided by the present application in combination with different embodiments.

[0054] The sulfonic acid cation exchange resin used in the embodiment is H + type, exchange capacity ≥4.8mmol / g; nano magnesium silicate particle size 20-50nm; hydroxyethyl cellulose aqueous solution viscosity 6500mPa·s; nano cerium oxide particle size 20-50nm.

[0055] Example 1

[0056] like Figure 1 As shown, a method for preparing a water-based paint for multi-material adhesion of an engine comprises the following steps:

[0057] 1. Soak the sulfonic acid cation exchange resin in deionized water for 24 hours until it is fully swollen; load it into a glass column with a diameter-to-height ratio of 1:5, pass a 5% hydrochloric acid solution at a flow rate of 2BV / h for 3 hours; rinse with deionized water until the pH of the effluent is 5; vacuum filter to a moisture content of 45% to obtain a pretreated resin; add the pretreated resin and 1.5 mol / L calcium chloride solution in a mass ratio of 1:8 to a reactor, heat to 40°C, stir at 200 rpm for 6 hours, and wash with deionized water until no precipitation is detected by 0.1 mol / L silver nitrate to obtain a calcium ion loaded resin; mix the calcium ion loaded resin with 1 wt% polyvinyl pyrrolidone solution in a mass ratio of 10:1; granulate with an extruder at 800 rpm to a pore size of 0.8 mm; pass through a 40-mesh sieve and a 60-mesh sieve in sequence, sieve the particles between 40-60 mesh, and vacuum dry to a moisture content of <3% to obtain a pre-coated calcium ion resin;

[0058] 2. Mix butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, and water, and pre-emulsify at 2000 rpm for 30 minutes to form a monomer emulsion. Heat a 10g / L ammonium persulfate solution to 75°C and slowly add the monomer emulsion dropwise. The mass ratio of butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, water, and ammonium persulfate solution is 50:35:4:1.5:30:80. Keep the temperature below 80°C and allow the mixture to drip over 3 hours. Keep the mixture warm for 1 hour, then cool to 40°C and filter through a 200-mesh sieve to obtain a water-based acrylic emulsion.

[0059] 3. Deionized water, sodium polyacrylate (molecular weight 8000 g / mol), and polydimethylsiloxane (viscosity 300 cSt) were mixed under stirring at 300 rpm, the pH was adjusted to 8.5 with 2-amino-2-methyl-1-propanol, and the mixture was stirred until completely dissolved. Zinc phosphate and nano-magnesium silicate were then added; after stirring, the mixture was passed through a 300-mesh sieve and then subjected to the grinding treatment described above. During the grinding process, the temperature was controlled using a water-cooling jacket to maintain the temperature below 40°C. After grinding, the mixture was passed through an 800-mesh sieve to obtain a sand-milled slurry; the mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate, and nano-magnesium silicate was 50:0.5:0.1:5:3;

[0060] Under stirring at 4.600 rpm, nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and 2 wt% hydroxyethyl cellulose aqueous solution are mixed in a mass ratio of 0.5:0.2:0.5:2 to obtain an additive; the sand-ground slurry is added to a water-based acrylic emulsion for 30 minutes, and then the additive and the pre-coated calcium ion resin are added. The mass ratio of the water-based acrylic emulsion, the sand-ground slurry, the pre-coated calcium ion resin and the additive is 50:30:5:2. Deionized water is added to a solid content of 40%, and the mixture is stirred evenly to obtain a water-based paint; the mixture is filtered through a 200-mesh vibrating sieve; and the mixture is filled with nitrogen in a sealed polyethylene barrel and stored below 30° C. to obtain the water-based paint for multi-material adhesion of engines.

[0061] Example 2

[0062] like Figure 1 As shown, a method for preparing a water-based paint for multi-material adhesion of an engine comprises the following steps:

[0063] 1. Soak the sulfonic acid cation exchange resin in deionized water for 24 hours until it is fully swollen; load it into a glass column with a diameter-to-height ratio of 1:5, pass a 5% hydrochloric acid solution at a flow rate of 2BV / h for 3 hours; rinse with deionized water until the effluent pH is 5.5; vacuum filter to a moisture content of 50% to obtain a pretreated resin; add the pretreated resin and 1.5 mol / L calcium chloride solution in a mass ratio of 1:6 to a reactor, heat to 40°C, stir at 200 rpm for 6 hours, and wash with deionized water until no precipitation is detected by 0.1 mol / L silver nitrate to obtain a calcium ion loaded resin; mix the calcium ion loaded resin with 1 wt% polyvinyl pyrrolidone solution in a mass ratio of 8:1; granulate with an extruder at a speed of 800 rpm to a pore size of 0.8 mm; pass through a 40-mesh sieve and a 60-mesh sieve in sequence, sieve the particles between 40-60 mesh, and vacuum dry to a moisture content of <3% to obtain a pre-coated calcium ion resin;

[0064] 2. Mix butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, and water, and pre-emulsify at 2000 rpm for 30 minutes to form a monomer emulsion. Heat a 10g / L ammonium persulfate solution to 75°C and slowly add the monomer emulsion dropwise. The mass ratio of butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, water, and ammonium persulfate solution is 50:35:4:1.5:30:80. Keep the temperature below 80°C and allow the mixture to drip over 3 hours. Keep the mixture warm for 1 hour, then cool to 40°C and filter through a 200-mesh sieve to obtain a water-based acrylic emulsion.

[0065] 3. Deionized water, sodium polyacrylate (molecular weight 7000 g / mol), and polydimethylsiloxane (viscosity 280 cSt) were mixed under stirring at 300 rpm, the pH was adjusted to 9.0 with 2-amino-2-methyl-1-propanol, and the mixture was stirred until completely dissolved. Zinc phosphate and nano-magnesium silicate were then added. After stirring, the mixture was passed through a 300-mesh sieve and subjected to the grinding treatment described above. During the grinding process, the temperature was controlled using a water-cooling jacket to maintain the temperature below 40°C. After grinding, the mixture was passed through an 800-mesh sieve to obtain a sand-milled slurry. The mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate, and nano-magnesium silicate was 50:1.0:0.3:8:5.

[0066] Under stirring at 4.600 rpm, nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and 2 wt% hydroxyethyl cellulose aqueous solution are mixed in sequence in a mass ratio of 1:0.5:1.0:3 to obtain an additive; the sand-ground slurry is added to a water-based acrylic emulsion for 45 minutes, and the additive and pre-coated calcium ion resin are added. The water-based acrylic emulsion, sand-ground slurry, pre-coated calcium ion resin and the additive are mixed in a mass ratio of 55:44:8:5, deionized water is added to a solid content of 45%, and the mixture is stirred evenly to obtain a water-based paint; the mixture is filtered through a 200-mesh vibrating sieve; and the mixture is filled with nitrogen in a sealed polyethylene barrel and stored below 30° C. to obtain the water-based paint for multi-material adhesion of engines.

[0067] Example 3

[0068] like Figure 1 As shown, a method for preparing a water-based paint for multi-material adhesion of an engine comprises the following steps:

[0069] 1. Soak the sulfonic acid cation exchange resin in deionized water for 24 hours until it is fully swollen; load it into a glass column with a diameter-to-height ratio of 1:5, pass a 5% hydrochloric acid solution at a flow rate of 2BV / h for 3 hours; rinse with deionized water until the pH of the effluent is 6; vacuum filter to a moisture content of 40% to obtain a pretreated resin; add the pretreated resin and 1.5 mol / L calcium chloride solution in a mass ratio of 1:7 to a reactor, heat to 40°C, stir at 200 rpm for 6 hours, and wash with deionized water until no precipitation is detected by 0.1 mol / L silver nitrate to obtain a calcium ion loaded resin; mix the calcium ion loaded resin with 1 wt% polyvinyl pyrrolidone solution in a mass ratio of 9:1; granulate with an extruder at 800 rpm to a pore size of 0.8 mm; pass through a 40-mesh sieve and a 60-mesh sieve in sequence, collect particles between 40-60 mesh, and vacuum dry to a moisture content of <3% to obtain a pre-coated calcium ion resin;

[0070] 2. Mix butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, and water, and pre-emulsify at 2000 rpm for 30 minutes to form a monomer emulsion. Heat a 10g / L ammonium persulfate solution to 75°C and slowly add the monomer emulsion dropwise. The mass ratio of butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, water, and ammonium persulfate solution is 50:35:4:1.5:30:80. Keep the temperature below 80°C and allow the mixture to drip over 3 hours. Keep the mixture warm for 1 hour, then cool to 40°C and filter through a 200-mesh sieve to obtain a water-based acrylic emulsion.

[0071] 3. Deionized water, sodium polyacrylate (molecular weight 7500 g / mol), and polydimethylsiloxane (viscosity 290 cSt) were mixed under stirring at 300 rpm, the pH was adjusted to 9.0 with 2-amino-2-methyl-1-propanol, and the mixture was stirred until completely dissolved. Zinc phosphate and nano-magnesium silicate were then added. After stirring, the mixture was passed through a 300-mesh sieve and subjected to the grinding treatment described above. During the grinding process, the temperature was controlled using a water-cooling jacket to maintain the temperature below 40°C. After grinding, the mixture was passed through an 800-mesh sieve to obtain a sand-milled slurry. The mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate, and nano-magnesium silicate was 50:0.8:0.2:7:4.

[0072] Under stirring at 4.600 rpm, nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and 2 wt% hydroxyethyl cellulose aqueous solution are mixed in a mass ratio of 0.8:0.3:0.8:2.5 to obtain an additive; the sand-ground slurry is added to a water-based acrylic emulsion for 40 minutes, the additive and the pre-coated calcium ion resin are added, and the mixture is stirred evenly. Deionized water is added to the solid content of 45% to obtain a water-based paint; the mass ratio of the water-based acrylic emulsion, the sand-ground slurry, the pre-coated calcium ion resin and the additive is 53:40:7:4; the mixture is filtered through a 200-mesh vibrating sieve; and the mixture is filled with nitrogen in a sealed polyethylene barrel and stored below 30° C. to obtain the water-based paint for multi-material adhesion of engines.

[0073] Example 4

[0074] like Figure 1 As shown, a method for preparing a water-based paint for multi-material adhesion of an engine comprises the following steps:

[0075] 1. Soak the sulfonic acid cation exchange resin in deionized water for 24 hours until it is fully swollen; load it into a glass column with a diameter-to-height ratio of 1:5, pass a 5% hydrochloric acid solution at a flow rate of 2BV / h for 3 hours; rinse with deionized water until the effluent pH is 6; vacuum filter to a moisture content of 40% to obtain a pretreated resin; add the pretreated resin and 1.5 mol / L calcium chloride solution in a mass ratio of 1:7 to a reactor, heat to 40°C, stir at 200 rpm for 6 hours, and wash with deionized water until no precipitation is detected by 0.1 mol / L silver nitrate to obtain a calcium ion-loaded resin; mix the calcium ion-loaded resin with a 1wt% polyvinylpyrrolidone solution in a mass ratio of 9:1; granulate with an extruder at a speed of 800 rpm to a pore size of 0.8 mm; pass through a 40-mesh sieve, and vacuum dry to a moisture content of <3% to obtain a pre-coated calcium ion resin;

[0076] 2. Mix butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, and water, and pre-emulsify at 2000 rpm for 30 minutes to form a monomer emulsion. Heat a 10g / L ammonium persulfate solution to 75°C and slowly add the monomer emulsion dropwise. The mass ratio of butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate, water, and ammonium persulfate solution is 50:35:4:1.5:30:80. Keep the temperature below 80°C and allow the mixture to drip over 3 hours. Keep the mixture warm for 1 hour, then cool to 40°C and filter through a 200-mesh sieve to obtain a water-based acrylic emulsion.

[0077] 3. Deionized water, sodium polyacrylate (molecular weight 7500 g / mol), and polydimethylsiloxane (viscosity 290 cSt) were mixed under stirring at 300 rpm, the pH was adjusted to 9.0 with 2-amino-2-methyl-1-propanol, and the mixture was stirred until completely dissolved. Zinc phosphate and nano-magnesium silicate were then added. After stirring, the mixture was passed through a 300-mesh sieve and then subjected to the grinding treatment described above. During the grinding process, the temperature was controlled using a water-cooling jacket to maintain the temperature below 40°C. After grinding, the mixture was passed through an 800-mesh sieve to obtain a sand-ground slurry. The mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate, and nano-magnesium silicate was 50:0.7:0.2:6:4.

[0078] Under stirring at 4.600 rpm, nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and 2 wt% hydroxyethyl cellulose aqueous solution are mixed in a mass ratio of 0.7:0.4:0.7:2.5 to obtain an additive; the sand-ground slurry is added to a water-based acrylic emulsion for 35 minutes, the additive and the pre-coated calcium ion resin are added, and the mixture is stirred evenly. Deionized water is added to the solid content of 45% to obtain a water-based paint; the mass ratio of the water-based acrylic emulsion, the sand-ground slurry, the pre-coated calcium ion resin and the additive is 53:38:6:4; the mixture is filtered through a 200-mesh vibrating sieve; and the mixture is filled with nitrogen in a sealed polyethylene barrel and stored below 30° C. to obtain the water-based paint for multi-material adhesion of engines.

[0079] Comparative Example 1

[0080] A method for preparing a water-based paint for multi-material adhesion of an engine, wherein the implementation steps and parameters are the same as those of Example 3, except that no pre-coated calcium ion resin is added.

[0081] Comparative Example 2

[0082] A method for preparing a water-based paint for multi-material adhesion of an engine, wherein the implementation steps and parameters are the same as those of Example 3, except that polyvinyl pyrrolidone is not added for granulation when preparing the pre-coated calcium ion resin, and the resin is directly dried before use.

[0083] Comparative Example 3

[0084] A method for preparing a water-based paint for multi-material adhesion of an engine, wherein the implementation steps and parameters are the same as those of Example 3, except that nano-magnesium silicate is not added.

[0085] Performance testing:

[0086] Low carbon steel was used as a substrate, and the water-based paint for engine multi-material adhesion prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was applied to the surface of the metal substrate. The coating was obtained after curing at 80° C. for 2 hours and tested.

[0087] Salt spray resistance test: According to GB / T1771, the coatings of Examples 1 to 4 and Comparative Examples 1 to 3 were subjected to a salt spray test at 35°C and 50 g / L NaCl in a salt spray chamber. The test results are shown in Table 1.

[0088] Electrochemical impedance spectroscopy (EIS) testing: The impedance value |Z| of the coating was tested in a 3.5% NaCl solution before and after the salt spray test. The results are shown in Table 1.

[0089] Adhesion test: The coatings of Examples 1 to 4 and Comparative Examples 1 to 3 were tested according to ASTM D3359. A 1 mm x 1 mm grid was drawn on the coating surface using the cross-hatch method. After applying tape, the coating was quickly peeled off and the proportion of coating detachment area was observed. The coating was scored on a scale of 0 to 5, with 0 indicating no detachment and higher grades indicating poorer adhesion. The results are shown in Table 1.

[0090] Scratch self-repair effect test: A scratch with a width of 100 μm was made on the coating surface. The coatings of Examples 1 to 4 and Comparative Examples 1 to 3 were immersed in a 3.5% NaCl solution. The rust condition of the scratched area was regularly observed. The results are shown in Table 1.

[0091] Table 1 Water-based paint coating performance test results

[0092]

[0093] As shown in Table 1, the salt spray resistance time of Examples 1 to 4 is 343-353h, which is significantly better than the 78-123h of the comparative example; the initial impedance value of the embodiment is 10 8 Ω·cm 2 , after salt spray, it still maintains 10 7 -10 8 Ω·cm 2 ; The impedance value of the comparative example is low and the attenuation is serious, and it drops to 10 after salt spray. 5 -10 6 Ω·cm 2The adhesion of the embodiment is level 0-1 (no peeling), while the adhesion of the comparative example is poor (level 2-4) due to incomplete formulation. The scratch repair rate of the embodiment is ≥92%, while the repair rate of the comparative example is 27% to 58%.

[0094] The formula of Comparative Example 1 does not contain pre-coated calcium ion resin, and only relies on leveling agent BYK-346 and hydroxyethyl cellulose. The salt spray resistance is 78h, which is significantly lower than that of the embodiment. The impedance value decays to 8.5×10 5 Ω·cm 2 , which is much lower than that of the embodiment, and the scratch self-repairing effect is only 35% (the embodiment is ≥92%). The pre-coated calcium ion resin is the core component of the self-repairing process. + Triggering Ca release 2+ , reacts with zinc phosphate to form a hydroxyapatite repair layer. Without this component, the coating cannot respond to the corrosive environment to repair, resulting in rapid rust at the scratches. Although hydroxyethyl cellulose can thicken, excessive use will destroy the density of the coating, and without resin fillers to fill defects, the corrosive medium is more likely to penetrate into the substrate. 2+ The release mechanism cannot form a dynamic barrier layer, and the impedance value drops significantly.

[0095] In Comparative Example 2, the pre-coated calcium ion resin was prepared without adding polyvinyl pyrrolidone for granulation and was used directly after drying. The salt spray resistance for 123h was better than that of Comparative Example 1, but much lower than that of the embodiment. The self-repair effect was 55% (the embodiment was ≥92%), and the impedance value after salt spray was only 1.2×10 6 Ω·cm 2 Polyvinyl pyrrolidone acts as a binder during the granulation process to ensure uniform resin particle size and complete surface coating. Ungranulated resin may be unevenly dispersed due to agglomeration or rough surface, and some Ca 2+ Released prematurely or blocked by the coating layer, the repair efficiency is reduced; irregular resin structure affects H + The permeation rate, resulting in Ca 2+ The release is delayed or insufficient, and the repair layer cannot be formed in time; the bonding force between the ungranulated resin and the substrate is weak, and the coating adhesion (grade 2) is inferior to that of the embodiment (grade 0).

[0096] Comparative Example 3: Without adding nano magnesium silicate, the salt spray resistance is poor, the salt spray resistance time is only 102h, and the impedance value after salt spray is only 5.0×10 5Ω·cm². The scratch self-repair effect is only 20%, and the adhesion is level 4 (severe flaking). Nano-magnesium silicate fills the coating's micropores, and its hydrolysis generates colloidal silicic acid, which blocks the diffusion path of the corrosive medium. Without it, the coating's density decreases, allowing the corrosive medium to quickly penetrate the substrate. Zinc phosphate provides anodic protection, but when used alone, it is prone to forming microporous defects. The absence of nano-magnesium silicate prevents the formation of the hydroxyapatite / silicic acid composite repair layer, resulting in a loss of dynamic barrier properties. Nano-magnesium silicate enhances coating toughness, but its absence results in poor adhesion (level 4) and easy flaking.

[0097] Adhesion test of different material parts on the engine:

[0098] Mild steel SAE1010, 6061 aluminum alloy, gray cast iron HT250, copper C11000, nylon 6, ABS+PC, and a two-component epoxy resin primer were used as substrates, respectively. The water-based paints for engine multi-material adhesion prepared in Examples 1 to 4 were applied to the substrates and cured at 80°C for 2 hours to obtain coatings. The coatings were tested according to ASTM D3359 by using the cross-hatch method. A 1 mm × 1 mm grid was drawn on the coating surface. After applying tape, the coating was quickly peeled off and the proportion of coating detachment area was observed. The coating was scored on a scale of 0-5, with 0 indicating no detachment and higher grades indicating poorer adhesion. The results are shown in Table 2.

[0099] Table 2 Adhesion test results of different material parts on the engine

[0100]

[0101] As shown in Table 2, the water-based paints for multi-material adhesion in engines prepared in Examples 1-4 of the present invention exhibited adhesion levels of 0-1 when applied to substrates of different materials in different engine locations, with virtually no peeling. This is because, when applied to metal substrates such as mild steel SAE1010, 6061 aluminum alloy, gray cast iron HT250, and copper C11000, the carboxyl groups in the water-based acrylic emulsion form hydrogen bonds or chemical bonds with the metal surface, while the zinc phosphate in the sanding slurry enhances adhesion by passivating the metal surface. Nano-magnesium silicate fills micropores, reducing interfacial defects, and the pre-coated calcium ion resin forms a hydroxyapatite repair layer upon corrosion triggering, strengthening the interfacial bond between the coating and the metal. On nylon 6 and ABS+PC substrates, the additive BYK-346 reduces the coating's surface tension and improves wettability on low-surface-energy plastics, while hydroxyethyl cellulose adjusts rheological properties, ensuring uniform coverage of the coating's microstructure. The flexible segments in the acrylic emulsion adapt to the plastic's thermal expansion coefficient, preventing peeling due to stress differences. The high surface activity of the two-component epoxy resin primer enables it to form chemical crosslinks with the acrylic groups of the water-based paint, enhancing interlayer adhesion; and the nano-magnesium silicate in the sanding slurry fills the microscopic pores of the epoxy coating, forming a dense transition layer and enhancing adhesion.

[0102] The above test data show that the water-based paint prepared by the present invention has high adhesion to different materials on the engine, is not easy to fall off, and can be used as an overall anti-corrosion paint for the engine.

[0103] The above results show and describe the basic principles and main features of this application as well as the advantages of this application.

[0104] Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in the present application is defined by the equivalents of the appended claims.

Claims

1. A water-based paint for multi-material adhesion of engines, characterized in that: include Water-based acrylic emulsion, sanding slurry, pre-coated calcium ion resin and additives; the additives include nano-cerium oxide, leveling agent BYK-346, adipic acid dihydrazide and hydroxyethyl cellulose aqueous solution; The sand grinding slurry contains zinc phosphate and nano-magnesium silicate; the pre-coated calcium ion resin is obtained by mixing and granulating a calcium ion-loaded resin and polyvinyl pyrrolidone; the calcium ion-loaded resin is obtained by treating a pretreated resin with a calcium chloride solution; the pretreated resin is obtained by soaking a sulfonic acid cation exchange resin in deionized water until it swells, adding a hydrochloric acid solution, and vacuum filtering.

2. The water-based paint for multi-material adhesion of engines according to claim 1, characterized in that: The sulfonic acid cation exchange resin is H + type, with an exchange capacity of ≥4.8mmol / g; the particle size of the nano magnesium silicate is 20-50nm.

3. The water-based paint for multi-material adhesion of engines according to claim 1, characterized in that: The mass ratio of the aqueous acrylic emulsion, the sand-grinding slurry, the pre-coated calcium ion resin and the auxiliary agent is (50-55):(30-44):(5-8):(2-5).

4. The water-based paint for multi-material adhesion of engines according to claim 1, characterized in that: The mass ratio of the nano-cerium oxide, the leveling agent BYK-346, the adipic acid dihydrazide and the hydroxyethyl cellulose aqueous solution is (0.5-1):(0.2-0.5):(0.5-1.0):(2-3); the particle size of the nano-cerium oxide is 20-50 nm.

5. The method for preparing a water-based paint for multi-material adhesion of an engine according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Pre-treating a sulfonic acid cation exchange resin, loading it with calcium ions, adding polyvinyl pyrrolidone, mixing and granulating the resin, and drying the resin to obtain a pre-coated calcium ion resin. S2, mixing zinc phosphate and nano magnesium silicate and grinding them to obtain a sand grinding slurry; S3. After adding the sand-milled slurry to the water-based acrylic emulsion, add the additives and the pre-coated calcium ion resin, stir evenly, add deionized water to a solid content of 40%-45%, and obtain a water-based paint; filter through a vibrating screen, and store in a nitrogen atmosphere to obtain the water-based paint for multi-material adhesion of the engine.

6. The method for preparing a water-based paint for multi-material adhesion of an engine according to claim 5, characterized in that: The preparation method of the pre-coated calcium ion resin described in S1 is specifically as follows: The sulfonic acid type cation exchange resin is soaked in deionized water until it swells, then loaded into a glass column, and hydrochloric acid solution is added to rinse until the pH of the effluent is within the range of 5-6, and then vacuum filtered to a water content of 40% to 50% to obtain a pretreated resin; The pretreated resin is reacted with a calcium chloride solution at a mass ratio of 1:(6-8), and washed until no chloride ions remain to obtain a calcium ion loaded resin; The calcium ion loaded resin and the polyvinyl pyrrolidone solution are mixed in a mass ratio of (8-10):1, granulated, sieved into 40-60 mesh particles, and vacuum dried to a moisture content of less than 3% to obtain a pre-coated calcium ion resin.

7. The method for preparing a water-based paint for multi-material adhesion of an engine according to claim 5, characterized in that: The preparation of the sand grinding slurry in S2 also includes: mixing deionized water, sodium polyacrylate, and polydimethylsiloxane, adjusting the pH to 8.5-9.0, and then adding zinc phosphate and nano-magnesium silicate; stirring until the fineness is ≤50 μm and then performing the grinding treatment to grind to a fineness of ≤15 μm; the mass ratio of deionized water, sodium polyacrylate, polydimethylsiloxane, zinc phosphate and nano-magnesium silicate is 50:(0.5-1.0):(0.1-0.3):(5-8):(3-5).

8. The method for preparing a water-based paint for multi-material adhesion of an engine according to claim 7, characterized in that: The molecular weight of the sodium polyacrylate is 7000-8000 g / mol; the viscosity of the polydimethylsiloxane is 280-300 cSt.

9. The method for preparing a water-based paint for multi-material adhesion of an engine according to claim 5, characterized in that: The preparation method of the aqueous acrylic emulsion in S3 is: mixing butyl acrylate, methyl methacrylate, acrylic acid, sodium lauryl sulfate and water, shearing and pre-emulsifying to form a monomer emulsion; adding the monomer emulsion dropwise into an ammonium persulfate solution, and filtering through a sieve to obtain the aqueous acrylic emulsion.

10. The method for preparing a water-based paint for multi-material adhesion of an engine according to claim 5, characterized in that: After adding deionized water as described in S3, filtration and nitrogen-filled storage are completed within 30 minutes, and the storage temperature is ≤30°C.

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