A wide adaptability water-based motorcycle engine coating and a preparation method thereof

Abstract

The present application belongs to the technical field of paint, and particularly relates to a wide adaptability water-based motorcycle engine paint and a preparation method thereof. The wide adaptability water-based motorcycle engine paint comprises the following components in parts by weight: base resin 38-52 parts, auxiliary agent 1-6 parts, solvent 23-46 parts and coloring agent 0-26 parts; wherein the base resin comprises water-based acrylic resin A, amino resin and adhesion promoter; the auxiliary agent comprises leveling agent, substrate wetting agent, defoaming agent A, thickening agent and neutralizing agent A; the solvent comprises water and cosolvent A; the coloring agent comprises water-based silver paste and / or water-based color paste; components of the water-based color paste comprise water-based acrylic resin B, pigment, water, dispersing agent, defoaming agent B, cosolvent B and neutralizing agent B. The wide adaptability water-based motorcycle engine paint in the present application can be used for the surface of a motorcycle aluminum alloy engine, and has the advantages of excellent adhesion, high hardness, salt mist resistance, acid and alkali resistance, aging resistance and the like.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a wide-adaptability water-based motorcycle engine coating and its preparation method. Background Technology

[0002] As the core power component of a motorcycle, the engine generates sustained high temperatures during operation, with surface temperatures reaching over 150°C. This necessitates that the coating possess excellent long-term heat resistance, preventing yellowing, chalking, cracking, or peeling. Secondly, when motorcycles are driven in rainy weather, after washing, or in humid environments, water splashes and moisture accumulates in the engine compartment. Simultaneously, corrosive media such as salt and acid rain on the road accelerate the electrochemical corrosion of the metal substrate. This requires the coating to possess superior rust prevention, salt spray resistance, and water resistance. Furthermore, considering the overall aesthetic quality of the motorcycle, the engine coating must also possess excellent decorative properties, such as long-lasting color, stable gloss, and the ability to withstand UV aging.

[0003] Traditional motorcycle engine coatings generally employ solvent-based systems, such as thermosetting acrylic-amino baking paints, polyester-amino baking paints, epoxy-phenolic coatings, and silicone heat-resistant coatings. These coatings, through efficient film-forming substances, large amounts of organic solvents, and potentially heavy metal anti-rust pigments like chromates, can construct dense, highly cross-linked films. However, solvent-based coatings release large amounts of volatile organic compounds (VOCs) during production, application, and drying. Furthermore, many high-performance solvent-based coatings require high-temperature baking for curing, which not only consumes a huge amount of energy but also limits their application to whole-machine painting, preventing their use in the repair market or on heat-sensitive components such as aluminum alloys. Faced with environmental pressures and the need for technological upgrades, water-based coatings have become an inevitable development direction. Water-based coatings use water as a dispersion medium and diluent, have extremely low VOC content, are non-toxic and odorless, and are non-flammable and non-explosive, offering unparalleled environmental and safety advantages. Existing water-based coatings mostly use water-based acrylic resins and epoxy resins as base materials. However, coatings made with water-based acrylic resins have relatively strict requirements for temperature and humidity during application. Motorcycle engines have a slightly complex structure with many uneven parts, and such coatings are prone to problems such as sagging, bubbling, paint accumulation at edges, and uneven gloss. Existing water-based acrylic resin-based coatings cannot meet these requirements. In addition, although some water-based silicone and fluorocarbon resins have good heat resistance, they have disadvantages such as high cost and poor adhesion. Furthermore, water has a high surface tension and a large latent heat of vaporization, resulting in poor wetting of the substrate by water-based coatings, making them more prone to defects such as pinholes, and the film density is often not as good as that of solvent-based coatings.

[0004] Therefore, there is an urgent need for a water-based motorcycle engine coating that is environmentally friendly, has excellent adhesion, high hardness, and is resistant to salt spray, acids and alkalis, and aging. Summary of the Invention

[0005] The purpose of this invention is to provide a versatile water-based motorcycle engine coating and its preparation method. The versatile water-based motorcycle engine coating of this invention can be applied to the surface of motorcycle aluminum alloy engines and has advantages such as excellent adhesion, high hardness, salt spray resistance, acid and alkali resistance, and aging resistance.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The first aspect of this invention provides a wide-adaptability water-based motorcycle engine coating, comprising, by weight, the following components: 38-52 parts of a base resin, 1-6 parts of additives, 23-46 parts of a solvent, and 0-26 parts of a colorant; wherein the base resin comprises water-based acrylic resin A, amino resin, and adhesion promoter; the additives comprise leveling agent, substrate wetting agent, defoamer A, thickener, and neutralizer A; the solvent comprises water and cosolvent A; the colorant comprises water-based silver paste and / or water-based color paste; the water-based color paste comprises water-based acrylic resin B, pigment, water, dispersant, defoamer B, cosolvent B, and neutralizer B.

[0008] The water involved in this invention can be deionized water, preferably with a conductivity of less than 10 μs / cm.

[0009] Preferably, the weight ratio of the waterborne acrylic resin A, amino resin and adhesion promoter is (25-40):(7-12):(1-5), and more preferably (30-35):(8-10):(3.5-4).

[0010] In this invention, specifically, controlling the above ratio can make the amino ratio of the system (i.e., the solid content ratio of waterborne acrylic resin A to amino resin) (2.3-2.8):1, which can better increase the anti-corrosion performance of the coating formed by the paint.

[0011] Preferably, the weight ratio of the leveling agent, substrate wetting agent, defoamer A, and thickener is (2-5):(1-5):(2-10):(1-10), and more preferably (3.5-4):(2.5-3):(5-6):(4-5).

[0012] Preferably, the pH value of the wide-adaptability water-based motorcycle engine coating is 8-8.5, and the amount of neutralizing agent A used is such that the pH value of the wide-adaptability water-based motorcycle engine coating is 8-8.5.

[0013] Preferably, the weight ratio of water to cosolvent A in the solvent is (20-40):(3-6), more preferably (30-35):(3.5-4).

[0014] In this invention, colorants may be added or not added as needed, but it is preferred to add colorants, and the preferred weight of the colorants is 5-15 parts.

[0015] In this invention, water-based silver paste and / or water-based color paste can be selected as needed. When the amount of water-based silver paste is 0, the water-based color paste is used as the coloring material, and the coating is a colored paint. When the amount of water-based color paste is 0, the water-based silver paste is used as the coloring material, and the product is a glitter paint. When both are present, the product is a glitter colored paint. During formulation design, the amount of each ingredient added needs to be within a certain range to ensure both the coloring power and hiding power of the coating, while also ensuring that the recoating performance of the coating is not affected by the addition of aluminum silver paste or color paste. Preferably, the colorant is water-based silver paste and water-based color paste, and the weight ratio of the water-based silver paste to the water-based color paste is (0-6):(0-20), preferably (2-3):(4-14).

[0016] Preferably, the waterborne acrylic resin A is the same as the waterborne acrylic resin B, and the preparation method of the waterborne acrylic resin A and the waterborne acrylic resin B includes: polymerizing the comonomer in the presence of an initiator and an organic solvent until the acid value of the reaction solution is 20-45 mgKOH / g; wherein, the comonomer includes butyl acrylate, acrylonitrile, acrylic acid and 1-allyl-3-vinylimidazolium dinitrileamine salt.

[0017] This invention has discovered that waterborne acrylic resin prepared using butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile amine salt can be used to prepare coatings, resulting in coatings with excellent adhesion and hardness, as well as excellent resistance to salt spray, water, and chemicals. It is speculated that this is because the vinyl and allyl groups in 1-allyl-3-vinylimidazolium dinitrile amine salt can participate in copolymerization, anchoring the imidazole cations and dinitrile amine anions to the polymer chain. At the same time, the dinitrile amine anions can form strong coordination bonds with the metal substrate, which can greatly enhance the adhesion. The resulting coating is dense and can effectively act as a barrier.

[0018] Preferably, the weight ratio of butyl acrylate, acrylonitrile, acrylic acid and 1-allyl-3-vinylimidazolium dinitrile is 100:(50-100):(30-80):(1-10), more preferably 100:(75-80):(50-60):(6-7).

[0019] In this invention, it was found that when the content of 1-allyl-3-vinylimidazolium dinitrile ammonium salt is too low, it cannot play its role in the system. However, when its content is too high, it reduces the adhesion, salt spray resistance, water resistance, and chemical resistance of the coating. It is speculated that this is because excessive 1-allyl-3-vinylimidazolium dinitrile ammonium salt will form local ion clusters, resulting in an uneven polymer resin structure and the existence of weak points. The uneven structure provides channels for media penetration, leading to a reduction in the coating's salt spray resistance, water resistance, and chemical resistance.

[0020] Preferably, the weight ratio of the comonomer to the organic solvent is (65-75):100.

[0021] Preferably, the organic solvent includes at least one of propylene glycol methyl ether, ethylene glycol monobutyl ether, isopropanol, n-butanol and isobutanol, and is more preferably ethylene glycol monobutyl ether.

[0022] Preferably, the weight ratio of the comonomer to the initiator is 100:(0.5-1).

[0023] Preferably, the initiator includes at least one of benzoyl peroxide, tert-butyl hydroperoxide, and azobisisobutyronitrile, with benzoyl peroxide being the most preferred.

[0024] Preferably, the polymerization reaction conditions include a temperature of 90-110℃. The polymerization reaction time is not specifically limited; sampling and measuring the acid value during the polymerization reaction to obtain a result of 20-45 mg KOH / g is sufficient.

[0025] Preferably, the preparation method of the waterborne acrylic resin A and the waterborne acrylic resin B includes: mixing butyl acrylate, acrylonitrile, acrylic acid, 1-allyl-3-vinylimidazolium dinitrile amine salt, ethylene glycol monobutyl ether, and benzoyl peroxide evenly, and carrying out a polymerization reaction at 90-110°C. During the polymerization reaction, the acid value of the reaction solution is continuously tested. When the acid value of the reaction solution is 20-45 mg KOH / g, the reaction is stopped, and the product is obtained; butyl acrylate, acrylonitrile, acrylic acid, and 1-... The weight ratio of allyl-3-vinylimidazolium dinitrile is 100:(75-80):(50-60):(6-7); the weight ratio of the total weight of butyl acrylate, acrylonitrile, acrylic acid and 1-allyl-3-vinylimidazolium dinitrile to ethylene glycol monobutyl ether is (65-75):100; the weight ratio of the total weight of butyl acrylate, acrylonitrile, acrylic acid and 1-allyl-3-vinylimidazolium dinitrile to benzoyl peroxide is 100:(0.5-1).

[0026] Preferably, the amino resin is a methylated melamine-formaldehyde resin.

[0027] The methyl etherified melamine-formaldehyde resin has a solid content of 80wt%-90wt% and can be obtained commercially. For example, the methyl etherified melamine-formaldehyde resin of model CYMEL 325 has a solid content of 80wt%.

[0028] Preferably, the adhesion promoter is selected from modified epoxy resin.

[0029] Preferably, the modified epoxy resin has a solid content of 50wt%-80wt%, more preferably 50wt%-75wt%.

[0030] Preferably, the modified epoxy resin includes waterborne acrylate modified epoxy resin, silicone modified epoxy resin, and phenolic epoxy vinyl ester resin.

[0031] Preferably, the weight ratio of the waterborne acrylate-modified epoxy resin, the silicone-modified epoxy resin and the phenolic epoxy vinyl ester resin is 1:(0.5-0.6):(0.1-0.15).

[0032] In this invention, it was found that controlling specific amounts of waterborne acrylate-modified epoxy resin, silicone-modified epoxy resin, and phenolic epoxy vinyl ester resin can better improve the overall performance of the final coating. This is presumably because the waterborne acrylate-modified epoxy resin can provide good compatibility and basic adhesion to the substrate and resin; the siloxane segments in the silicone-modified epoxy resin can migrate to the coating surface, providing excellent hydrophobicity and weather resistance; and the phenolic epoxy vinyl ester resin has high rigidity, high temperature resistance, and excellent chemical resistance (especially acid and alkali resistance). The synergistic effect of the three can achieve a "substrate-intermediate-surface" synergistic effect, that is, substrate adhesion, intermediate layer toughness, and surface protection.

[0033] The waterborne acrylate-modified epoxy resin in this invention can be obtained commercially, for example, purchased from Jining Tangyi Chemical Co., Ltd., model S-931, with a solid content of 70wt%.

[0034] The organosilicon-modified epoxy resin in this invention can be obtained commercially, for example, purchased from Jining Tangyi Chemical Co., Ltd., model TY-H26, with a solid content of 50wt%.

[0035] The phenolic epoxy vinyl ester resin in this invention is commercially available, for example, purchased from Yixing Yanglin New Material Co., Ltd., model 907, with a solid content of 62 wt%.

[0036] Preferably, the leveling agent is selected from one or more of polymethyl alkyl polyethylene glycol ether copolymer leveling agents, polyacrylate leveling agents, and fluorinated polyacrylate leveling agents, and is preferably a fluorinated polyacrylate leveling agent. The fluorinated polyacrylate leveling agent is commercially available, for example, BASF Efka FL 3772.

[0037] Preferably, the substrate wetting agent is selected from polyether-modified siloxane solution, wherein the polyether-modified siloxane solution is commercially available, for example, Momentive Silwet L-77.

[0038] Preferably, the defoamer A and the defoamer B are each independently a silicone defoamer and / or a mixture of hydrophobic particles and a defoaming polymer, preferably a silicone defoamer, wherein the silicone defoamer is commercially available, for example, Evonik TEGO FOAMEX 825.

[0039] Preferably, the thickener is at least one of a pseudoplastic polyurethane thickener or a Newtonian polyurethane thickener; wherein the thickener is commercially available, for example, Borchi Gel 0434 associative type.

[0040] Preferably, the aqueous silver paste is a coated aqueous silver paste with a Dv50 particle size range of 5-50 μm and a non-volatile content of 50-80%. The aqueous silver paste in this invention can be obtained commercially, for example, the aqueous silver paste purchased from Zhaoqing Dongyang Aluminum Co., Ltd., model EMR-D-F290, with a Dv50 particle size range of 10 μm and a non-volatile content of 55±1%.

[0041] The pigments used in this invention can be selected as needed, such as pigment carbon black, phthalocyanine blue, etc. Among them, pigment carbon black is generally divided into low pigment carbon black and medium-high pigment carbon black. For example, the low pigment carbon black model is Orion low pigment carbon black XPB366, and the medium-high pigment carbon black model is Cabot Special Pigment Carbon Black M900.

[0042] Preferably, the dispersant is selected from at least one of polyvinylpyrrolidone, vinylpyrrolidone, carboxymethyl cellulose and sodium lignosulfonate, and is preferably carboxymethyl cellulose; wherein, carboxymethyl cellulose is commercially available, for example, carboxymethyl cellulose CM-52.

[0043] Preferably, the cosolvent A and cosolvent B are each an alcohol ether solvent.

[0044] Preferably, the alcohol ether solvent is at least one of ethylene glycol monobutyl ether, diethylene glycol butyl ether, or propylene glycol methyl ether, and more preferably ethylene glycol monobutyl ether. That is, co-solvent A is at least one of ethylene glycol monobutyl ether, diethylene glycol butyl ether, or propylene glycol methyl ether, and more preferably ethylene glycol monobutyl ether; co-solvent B is at least one of ethylene glycol monobutyl ether, diethylene glycol butyl ether, or propylene glycol methyl ether, and more preferably ethylene glycol monobutyl ether.

[0045] Preferably, neutralizing agent A and neutralizing agent B are each independently selected from at least one of 2-amino-2-methyl-1-propanol (AMP-95), N,N-dimethylethanolamine and triethylamine, preferably N,N-dimethylethanolamine.

[0046] Preferably, the components of the water-based color paste further include α-tricalcium phosphate; that is, the components of the water-based color paste include water-based acrylic resin B, α-tricalcium phosphate, pigment, water, dispersant, defoamer B, cosolvent B and neutralizer B.

[0047] Preferably, by weight, the components of the water-based color paste include 5-15 parts of water-based acrylic resin B, 2-8 parts of tricalcium α-phosphate, 5-30 parts of pigment, 0.5-5 parts of dispersant, 0.1-3 parts of defoamer B, 2-10 parts of cosolvent B, 0.1-3 parts of neutralizer B, and water to make up to 100 parts.

[0048] Preferably, by weight, the components of the water-based color paste further include 8-10 parts of water-based acrylic resin B, 4-5 parts of tricalcium α-phosphate, 5-30 parts of pigment, 1-2 parts of dispersant, 0.3-1 part of defoamer B, 5-6 parts of cosolvent B, 0.5-2 parts of neutralizer B, and water to make up to 100 parts.

[0049] In this invention, water-based pigment pastes can be formulated into application pigment pastes with different pigment concentrations according to the characteristics of the pigments. For example, medium-high pigment carbon black can be made into an application black paste with a concentration of 10-15%, low pigment carbon black can be made into an application pigment paste with a concentration of 20-30%, and phthalocyanine blue can be made into an application paste with a concentration of 10-20%.

[0050] Preferably, the method for preparing the water-based pigment includes:

[0051] (1) Add waterborne acrylic resin B, α-tricalcium phosphate, pigment, dispersant, cosolvent B and water into a shearing machine and shear at a speed of 8000-10000 rpm for 5-10 minutes. Then add defoamer B and neutralizer B and continue shearing for 1-2 minutes to obtain the mixture.

[0052] (2) Add grinding zircon beads with a particle size of 0.8-1.5mm into the dispersion cylinder of the sand mill, and then add the mixture from step (1) into the sand mill. Set the speed of the dispersion sand mill to 1500-2000r / min, grind for 1-2h, and finally pass through a 200-400 mesh sieve to obtain water-based color paste.

[0053] Preferably, the weight of the ground zirconium beads is 1-1.5 times the weight of the mixture.

[0054] Existing color pastes often lack resin-based grinding and dispersion. When the coating contains a large amount of co-solvent, the stable state of the color paste is easily disrupted, leading to precipitation, flocculation, and other phenomena. This results in loss of gloss and reduced hiding power after spraying. However, the water-based color paste of this invention incorporates water-based acrylic resin with good pigment dispersibility for grinding, achieving better pigment stabilization. This facilitates pigment wetting, dispersion, and long-term stability, reducing the risk of stability degradation when the water-based color paste is added to the resin base. This not only improves the impact resistance of the color paste and reduces flocculation, but also maintains good gloss of the overall coating. Furthermore, research has found that adding an appropriate amount of α-tricalcium phosphate to the color paste can significantly increase the salt spray resistance of the coating, presumably because α-tricalcium phosphate is slightly soluble in water and can continuously and slowly release Ca2+. 2+ and PO4 3- Ions. In the early stages of corrosion, these ions react with Fe dissolved from the anolyte. 2+ The reaction generates a dense iron phosphate passivation film, which effectively inhibits the anodic reaction, thus exhibiting excellent salt spray resistance.

[0055] Preferably, the method for preparing the water-based pigment includes:

[0056] (1) Prepare the following raw materials by weight: 8-10 parts of the above waterborne acrylic resin B, 4-5 parts of α-tricalcium phosphate, 5-30 parts of pigment carbon black, 1-2 parts of carboxymethyl cellulose, 5-6 parts of ethylene glycol monobutyl ether, 0.3-1 parts of defoamer B, 0.5-2 parts of N,N-dimethylethanolamine, and deionized water to make up to 100 parts;

[0057] (2) Add waterborne acrylic resin B, α-tricalcium phosphate, pigment carbon black, carboxymethyl cellulose, ethylene glycol monobutyl ether and deionized water into a shearing machine and shear at a speed of 8000-10000 rpm for 5-10 minutes. Then add N,N-dimethylethanolamine and continue shearing for 1-2 minutes to obtain the mixture.

[0058] (3) Add grinding zirconium beads with a particle size of 0.8-1.5 mm into the dispersion cylinder of the sand mill, and then add the mixture from step (2) into the sand mill. Set the speed of the dispersion sand mill to 1500-2000 r / min, grind for 1-2 hours, and finally pass through a 200-400 mesh sieve to obtain water-based color paste. The weight of the grinding zirconium beads is 1-1.5 times the weight of the mixture.

[0059] The second aspect of the present invention provides a method for preparing the wide-adaptability waterborne motorcycle engine coating described in the first aspect of the present invention. The preparation method includes mixing a base resin, an additive, a colorant, and a solvent to obtain the coating.

[0060] Preferably, the preparation method of the wide-adaptability water-based motorcycle engine coating includes:

[0061] S1: Add the water-based silver paste to reactor A, then add cosolvent A and thickener and mix to obtain a paste. Soak for 1-2 hours and set aside.

[0062] S2: Add water-based acrylic resin A to reactor B, and adjust the pH value to 7.5-8.5 by adding neutralizing agent A at a rotation speed of 500rpm-1000rpm.

[0063] S3: Add water to reactor B and disperse for 5-10 minutes at a speed of 500-1000 rpm;

[0064] S4: While dispersing, add leveling agent, substrate wetting agent and defoamer A into reactor B with a rotation speed of 500rpm-1000rpm, and disperse for 5-10 minutes under this condition;

[0065] S5: While dispersing, add the amino resin and adhesion promoter to reactor B with a rotation speed of 500rpm-1000rpm, and disperse under this condition for 5-10min;

[0066] S6: While dispersing the material in reactor A, add it to reactor B at a speed of 500 rpm-1000 rpm. After adding the material, continue to disperse it under these conditions for 5-10 minutes.

[0067] S7: While dispersing, add the water-based pigment to reactor B at a rotation speed of 500 rpm-1000 rpm, and disperse under these conditions for 5-10 minutes;

[0068] S8: Adjust the pH value to between 8.0 and 8.5 with neutralizing agent A, then disperse at 800 rpm to 1500 rpm for 20 to 30 minutes, and then filter to obtain the product.

[0069] There are no special restrictions on the mixing in step S1 of this invention; the mixture can be stirred until it becomes a homogeneous slurry.

[0070] In this invention, different mesh sizes of filter screens can be selected for filtration according to the coarseness of the water-based silver paste, for example, filtration with a 120-200 mesh filter screen.

[0071] The coating of this invention can be diluted with a thinner (e.g., deionized water with a conductivity of less than 10 μs / cm) to a spraying viscosity of 20-30 s / Ford-4 cup (25°C) before use. When using it, it can be applied using general-purpose wheel spraying methods such as air spraying or electrostatic spraying. Those skilled in the art can select the specific spraying method and conditions as needed, which will not be elaborated in detail in this invention. Furthermore, the coating curing conditions can be 140-160°C for 20-30 minutes.

[0072] Compared with the prior art, the present invention has at least the following beneficial effects:

[0073] The coating components of this invention have good compatibility and synergistic effects, which can simultaneously achieve high adhesion, high crosslinking density, excellent weather resistance and active anti-corrosion capability. At the same time, the entire system does not rely on heavy metal anti-rust pigments and has extremely low VOC content, achieving a perfect balance between high performance and environmental safety. Attached Figure Description

[0074] Figure 1 This is a picture of a sample using the coating from Example 1 after 240 hours of resistance to neutral salt spray.

[0075] Figure 2 This is a picture of a sample using the coating from Example 2 after 240 hours of resistance to neutral salt spray.

[0076] Figure 3 Images of a sample using the coating from Example 3 after 240 hours of resistance to neutral salt spray.

[0077] Figure 4 The image shows a sample using the coating from Comparative Example 1 after 240 hours of resistance to neutral salt spray.

[0078] Figure 5 The image shows a sample using the coating from Comparative Example 5 after 240 hours of resistance to neutral salt spray.

[0079] Figure 6 The image shows a sample using the coating from Comparative Example 6 after 240 hours of resistance to neutral salt spray. Detailed Implementation

[0080] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0081] In the following examples and comparative examples:

[0082] The carboxymethyl cellulose is designated as carboxymethyl cellulose CM-52.

[0083] The waterborne acrylate-modified epoxy resin was purchased from Jining Tangyi Chemical Co., Ltd., model S-931, with a solid content of 70 wt%.

[0084] The silicone-modified epoxy resin was purchased from Jining Tangyi Chemical Co., Ltd., model TY-H26, with a solid content of 50 wt%.

[0085] The phenolic epoxy vinyl ester resin was purchased from Yixing Yanglin New Material Co., Ltd., model number 907, with a solid content of 62 wt%.

[0086] The amino resin is a methylated melamine-formaldehyde resin, model number CYMEL 325, with a solid content of 80 wt%.

[0087] The leveling agent is BASF Efka FL 3772 fluorinated modified polyacrylate leveling agent;

[0088] The substrate wetting agent is Momentive Silwet L-77 polyether-modified siloxane solution;

[0089] The defoamer is Evonik TEGO FOAMEX 825 silicone defoamer;

[0090] The thickener is Borchi Gel 0434, an associative thickener.

[0091] The water-based silver paste was purchased from Zhaoqing Dongyang Aluminum Co., Ltd., model EMR-D-F290, with a Dv50 particle size range of 10μm and a non-volatile content of 55±1%.

[0092] Example 1

[0093] Preparation of waterborne acrylic resin:

[0094] Butyl acrylate, acrylonitrile, acrylic acid, 1-allyl-3-vinylimidazolium dinitrile (APPD) salt, ethylene glycol monobutyl ether, and benzoyl peroxide were mixed evenly and polymerized at 95°C. The acid value of the reaction solution was continuously tested during the polymerization reaction. The reaction was stopped when the acid value of the reaction solution reached 36 mg KOH / g. The weight ratio of butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile (APPD) salt was 100:78:55:6.5; the weight ratio of the total weight of butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile (APPD) salt to ethylene glycol monobutyl ether was 70:100; and the weight ratio of the total weight of butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile (APPD) salt to benzoyl peroxide was 100:0.82.

[0095] Preparation of water-based color pastes:

[0096] (1) Prepare the following raw materials by weight: 8 parts of the above water-based acrylic resin, 5 parts of α-tricalcium phosphate, 12 parts of medium-high pigment carbon black, 1.2 parts of carboxymethyl cellulose, 5.6 parts of ethylene glycol monobutyl ether, 0.5 parts of defoamer B, 1.1 parts of N,N-dimethylethanolamine, and deionized water to make up to 100 parts.

[0097] (2) Add waterborne acrylic resin B, α-tricalcium phosphate, medium-high pigment carbon black, carboxymethyl cellulose, ethylene glycol monobutyl ether and deionized water into a shearing machine and shear at 8000 rpm for 10 minutes. Then add defoamer and N,N-dimethylethanolamine and continue shearing for 1 minute to obtain the mixture.

[0098] (3) Add 1.2 mm diameter grinding zircon beads to the dispersion cylinder of the sand mill, then add the mixture from step (2) to the sand mill, set the speed of the dispersion sand mill to 2000 r / min, grind for 1 h, and finally pass through a 400 mesh sieve to obtain water-based color paste, wherein the weight of the grinding zircon beads is 1 times the weight of the mixture.

[0099] Preparation of coatings:

[0100] First, prepare the following components by weight: 34 parts of the above-mentioned water-based acrylic resin, 8 parts of amino resin, 4 parts of adhesion promoter, 0.35 parts of leveling agent, 0.28 parts of substrate wetting agent, 0.52 parts of defoamer, 0.4 parts of thickener, 33 parts of deionized water, 3.5 parts of ethylene glycol monobutyl ether, 2 parts of water-based silver paste, and 12 parts of the above-mentioned water-based color paste; the adhesion promoter is a water-based acrylic ester modified epoxy resin, silicone modified epoxy resin, and phenolic epoxy vinyl ester resin in a weight ratio of 1:0.55:0.12.

[0101] Next, prepare N,N-dimethylethanolamine;

[0102] The coating was prepared according to the following method:

[0103] S1: Add the water-based silver paste to reactor A, then add ethylene glycol monobutyl ether and thickener and mix and stir until a homogeneous paste is formed. Soak for 1.5 hours and set aside.

[0104] S2: Add the above-mentioned water-based acrylic resin to reactor B, and adjust the pH value to 7 by adding N,N-dimethylethanolamine at a rotation speed of 8000 rpm.

[0105] S3: Add deionized water to reactor B and disperse it for 8 minutes at a speed of 800 rpm;

[0106] S4: While dispersing, add the leveling agent, substrate wetting agent, and defoamer to reactor B at a speed of 800 rpm, and disperse for 8 minutes under these conditions;

[0107] S5: Add the amino resin and adhesion promoter to reactor B at a speed of 800 rpm while dispersing them, and disperse them for 8 minutes under these conditions;

[0108] S6: While dispersing the material in reactor A, add it to reactor B at a rotation speed of 800 rpm. After adding the material, continue to disperse it under these conditions for 8 minutes.

[0109] S7: While dispersing the above-mentioned water-based pigment, add it to reactor B at a speed of 800 rpm and disperse it for 8 minutes under these conditions;

[0110] S8: Adjust the pH to between 8 and 2 with N,N-dimethylethanolamine, then disperse at 1500 rpm for 20 min, and finally filter through a 180-mesh filter to obtain the product.

[0111] Example 2

[0112] Preparation of waterborne acrylic resin: Same as in Example 1;

[0113] Preparation of water-based color paste: Same as in Example 1;

[0114] Preparation of coatings:

[0115] First, prepare the following components by weight: 33 parts of the above-mentioned water-based acrylic resin, 12 parts of amino resin, 2.5 parts of adhesion promoter, 0.36 parts of leveling agent, 0.25 parts of substrate wetting agent, 0.5 parts of defoamer, 0.4 parts of thickener, 32 parts of deionized water, 3.8 parts of ethylene glycol monobutyl ether, 2 parts of water-based silver paste, and 12 parts of the above-mentioned water-based color paste; the adhesion promoter is a water-based acrylic ester modified epoxy resin, silicone modified epoxy resin, and phenolic epoxy vinyl ester resin in a weight ratio of 1:0.6:0.1.

[0116] Next, prepare N,N-dimethylethanolamine;

[0117] The coating was prepared according to the following method:

[0118] S1: Add the water-based silver paste to reactor A, then add ethylene glycol monobutyl ether and thickener and mix and stir until a homogeneous paste is formed. Soak for 2 hours and set aside.

[0119] S2: Add the above-mentioned water-based acrylic resin to reactor B, and adjust the pH value to 7.2 by adding N,N-dimethylethanolamine at a rotation speed of 1000 rpm.

[0120] S3: Add deionized water to reactor B and disperse it for 5 minutes at a speed of 1000 rpm;

[0121] S4: While dispersing, add the leveling agent, substrate wetting agent, and defoamer to reactor B at a speed of 1000 rpm, and disperse for 6 minutes under these conditions;

[0122] S5: While dispersing, add the amino resin and adhesion promoter to reactor B at a speed of 1000 rpm, and disperse for 8 minutes under these conditions;

[0123] S6: While dispersing the material in reactor A, add it to reactor B at a speed of 1000 rpm. After adding the material, continue to disperse it under these conditions for 5 minutes.

[0124] S7: While dispersing the above-mentioned water-based pigment, add it to reactor B at a speed of 1000 rpm and disperse it for 6 minutes under these conditions;

[0125] S8: Adjust the pH to between 8 and 2 with N,N-dimethylethanolamine, then disperse at 1500 rpm for 20 min, and finally filter through a 120-mesh filter to obtain the product.

[0126] Example 3

[0127] Preparation of waterborne acrylic resin:

[0128] Butyl acrylate, acrylonitrile, acrylic acid, 1-allyl-3-vinylimidazolium dinitrile (APPD) salt, ethylene glycol monobutyl ether, and benzoyl peroxide were mixed evenly and polymerized at 90°C. The acid value of the reaction solution was continuously tested during the polymerization reaction. The reaction was stopped when the acid value of the reaction solution reached 45 mg KOH / g. The weight ratio of butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile (APPD) salt was 100:75:60:7; the weight ratio of the total weight of butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile (APPD) salt to ethylene glycol monobutyl ether was 75:100; and the weight ratio of the total weight of butyl acrylate, acrylonitrile, acrylic acid, and 1-allyl-3-vinylimidazolium dinitrile (APPD) salt to benzoyl peroxide was 100:1.

[0129] Preparation of water-based color pastes:

[0130] (1) Prepare the following raw materials by weight: 8.2 parts of the above water-based acrylic resin, 4.6 parts of α-tricalcium phosphate, 20 parts of low-pigment carbon black, 1.5 parts of carboxymethyl cellulose, 5.4 parts of ethylene glycol monobutyl ether, 1.3 parts of N,N-dimethylethanolamine, and deionized water to make up to 100 parts.

[0131] (2) Add waterborne acrylic resin B, α-tricalcium phosphate, pigment, carboxymethyl cellulose, ethylene glycol monobutyl ether and deionized water into a shearing machine and shear at 9000 rpm for 8 minutes. Then add defoamer and N,N-dimethylethanolamine and continue shearing for 1 minute to obtain the mixture.

[0132] (3) Add 1.2 mm of ground zirconia beads to the dispersion cylinder of the sand mill, then add the mixture from step (2) to the sand mill, set the speed of the dispersion sand mill to 1800 r / min, grind for 1.5 h, and finally pass through a 400 mesh sieve to obtain water-based color paste; wherein, the weight of the ground zirconia beads is 1.5 times the weight of the mixture.

[0133] Preparation of coating: The coating was prepared according to the method of Example 1, except that the water-based acrylic resin and water-based color paste of this example were used.

[0134] Comparative Example 1

[0135] The method of Example 3 differs in that:

[0136] Replace 1-allyl-3-vinylimidazolium dinitrile with hexyl acrylate.

[0137] The final product is a water-based acrylic resin, as well as the corresponding water-based color paste and the corresponding coating.

[0138] Comparative Example 2

[0139] The method of Example 3 differs in that:

[0140] The weight ratio of butyl acrylate, acrylonitrile, acrylic acid and 1-allyl-3-vinylimidazolium dinitrile is 100:75:60:15;

[0141] The final product is a water-based acrylic resin, as well as the corresponding water-based color paste and the corresponding coating.

[0142] Comparative Example 3

[0143] The method of Example 3 differs in that:

[0144] The adhesion promoter is a waterborne acrylate-modified epoxy resin, an organosilicon-modified epoxy resin, and a phenolic epoxy vinyl ester resin in a weight ratio of 0.67:0.5:0.5.

[0145] The final product is a water-based acrylic resin, as well as the corresponding water-based color paste and the corresponding coating.

[0146] Comparative Example 4

[0147] The method of Example 3 differs in that:

[0148] The adhesion promoter is a waterborne acrylate-modified epoxy resin, an organosilicon-modified epoxy resin, and a phenolic epoxy vinyl ester resin in a weight ratio of 0.5:0.5:0.67.

[0149] Comparative Example 5

[0150] The method of Example 3 differs in that:

[0151] Replace tricalcium alpha phosphate with Cabot CAB-O-SIL TS620 silica.

[0152] The final product is a water-based color paste and a corresponding coating.

[0153] Comparative Example 6

[0154] The method according to Example 1 differs in that:

[0155] Replace 1-allyl-3-vinylimidazolium dinitrile with hexyl acrylate.

[0156] The final product is a water-based acrylic resin, as well as the corresponding water-based color paste and the corresponding coating.

[0157] Performance testing

[0158] The coatings of Examples 1-3 and Comparative Examples 1-6 were subjected to the following performance tests according to the test methods in Table 1.

[0159] The test results of the coatings in Examples 1-3 and Comparative Examples 1-2 are shown in Table 2.

[0160] The test results of the coatings in Comparative Examples 3-6 are shown in Table 3.

[0161] Images of samples using the coating from Example 1 after 240 hours of resistance to neutral salt spray are shown below. Figure 1 As shown, the corrosion on one side of the scribed area was measured to be 0.8 mm, while there were no abnormalities in the non-scribed areas.

[0162] Images of samples using the coating from Example 2 after 240 hours of resistance to neutral salt spray are shown below. Figure 2 As shown, the corrosion on one side of the scribed area was measured to be 1.0 mm, while there were no abnormalities in the non-scribed areas.

[0163] Images of samples using the coating from Example 3 after 240 hours of resistance to neutral salt spray are shown below. Figure 3 As shown, the corrosion on one side of the scribed area was measured to be 0.5 mm, while there were no abnormalities in the non-scribed areas.

[0164] Images of samples using the coating from Comparative Example 1 after 240 hours of resistance to neutral salt spray are shown below. Figure 4As shown, the corrosion on one side of the scribed area was measured to be 3.5 mm, while the non-scribed area showed partial pitting corrosion.

[0165] Images of samples using the coating from Comparative Example 5 after 240 hours of resistance to neutral salt spray are shown below. Figure 5 As shown, the corrosion on one side of the scribed area was measured to be 1.8 mm, while there were no abnormalities in the non-scribed areas.

[0166] Images of samples using the coating from Comparative Example 6 after 240 hours of resistance to neutral salt spray are shown below. Figure 6 As shown, the corrosion on one side of the scribed area was measured to be 3.5 mm, while the non-scribed area showed partial pitting corrosion.

[0167] Table 1. Test methods for performance testing

[0168]

[0169] Table 2 Test results of coatings in Examples 1-3 and Comparative Examples 1-2

[0170]

[0171]

[0172] Table 3 shows the test results of the coatings in Comparative Examples 3-6.

[0173]

[0174]

[0175] As can be seen from the above performance test results, the coatings in Examples 1-3 are water-based coatings, and their key performance indicators such as pencil hardness, adhesion, salt spray resistance, acid and alkali resistance, and aging resistance have reached a level comparable to high-performance solvent-based coatings.

[0176] The comparative examples, lacking the necessary technical solutions, performed significantly worse than the exemplary examples in relevant performance tests. In Comparative Examples 1 and 6, replacing 1-allyl-3-vinylimidazolium dinitrile with hexyl acrylate resulted in a decrease in the final coating's chemical resistance, adhesion, and weather resistance. This may be because the coating system could not effectively form ionic crosslinks and hydrogen bond networks. In Comparative Example 2, increasing the proportion of 1-allyl-3-vinylimidazolium dinitrile led to a decrease in the final coating's adhesion, possibly because excessively high crosslink density could cause brittleness. Increasing the amount of imidazole salt may lead to instability in the polymerization system, or even phase separation. In Comparative Examples 3-4, the proportions of the accelerator components were adjusted, and the chemical resistance, adhesion, and weather resistance of the final coating all decreased. This may be because an excessively high proportion of phenolic epoxy vinyl ester may lead to excessive rigidity of the system and decreased adhesion. An improper proportion of organosilicon-modified epoxy resin may affect interfacial compatibility and resistance to damp heat. In Comparative Example 5, α-tricalcium phosphate was replaced with silica, and the salt resistance of the final coating decreased. This may be because α-tricalcium phosphate has corrosion inhibition and barrier effects.

[0177] The above experimental results further demonstrate the importance of the technical solution defined in this invention to its technical effect.

[0178] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A water-based motorcycle engine coating, characterized in that, By weight, it comprises the following components: 38-52 parts of matrix resin, 1-6 parts of additives, 23-46 parts of solvent and 0-26 parts of colorant; The matrix resin includes waterborne acrylic resin A, amino resin and adhesion promoter, in a weight ratio of (25-40):(7-12):(1-5); Additives include leveling agents, substrate wetting agents, defoamer A, thickeners, and neutralizer A; The solvents include water and cosolvent A; Colorants include water-based silver paste and / or water-based colorant; The adhesion promoter is a modified epoxy resin, which includes waterborne acrylate modified epoxy resin, silicone modified epoxy resin and phenolic epoxy vinyl ester resin, with a weight ratio of 1:(0.5-0.6):(0.1-0.15). By weight, the components of the water-based color paste include 5-15 parts of water-based acrylic resin B, 2-8 parts of tricalcium α-phosphate, 5-30 parts of pigment, 0.5-5 parts of dispersant, 0.1-3 parts of defoamer B, 2-10 parts of cosolvent B, 0.1-3 parts of neutralizer B, and water to make up to 100 parts. Waterborne acrylic resin A is the same as waterborne acrylic resin B, and its preparation method includes: the comonomer is polymerized in the presence of an initiator and an organic solvent until the acid value of the reaction solution is 20-45 mg KOH / g, and the comonomer includes butyl acrylate, acrylonitrile, acrylic acid and 1-allyl-3-vinylimidazolium dinitrile amine salt, with a weight ratio of 100:(50-100):(30-80):(1-10).

2. The water-based motorcycle engine coating according to claim 1, characterized in that, The weight ratio of the leveling agent, substrate wetting agent, defoamer A, and thickener is (2-5):(1-5):(2-10):(1-10); the pH value of the water-based motorcycle engine coating is 8-8.5, and the amount of neutralizing agent A used makes the pH value of the water-based motorcycle engine coating 8-8.5; the weight ratio of water to cosolvent A in the solvent is (20-40):(3-6); the colorant includes water-based silver paste and water-based color paste, and the weight ratio of water-based silver paste to water-based color paste is (0-6):(0-20).

3. The water-based motorcycle engine coating according to claim 1, characterized in that, The weight ratio of the comonomer to the organic solvent is (65-75):100; the weight ratio of the comonomer to the initiator is 100:(0.5-1).

4. The water-based motorcycle engine coating according to claim 3, characterized in that, The organic solvent includes at least one of propylene glycol methyl ether, ethylene glycol monobutyl ether, isopropanol, n-butanol, and isobutanol; the initiator includes at least one of benzoyl peroxide, tert-butyl hydroperoxide, and azobisisobutyronitrile; the polymerization reaction conditions include a temperature of 90-110°C.

5. The water-based motorcycle engine coating according to claim 1, characterized in that, The amino resin is a methylated melamine-formaldehyde resin; the modified epoxy resin has a solid content of 50wt%-80wt%.

6. The water-based motorcycle engine coating according to claim 1, characterized in that, The leveling agent is selected from one or more of polymethyl alkyl polyethylene glycol ether copolymer leveling agents, polyacrylate leveling agents, and fluorinated polyacrylate leveling agents; the substrate wetting agent is selected from polyether modified siloxane solution; the defoamer A and defoamer B are each independently silicone defoamers, and / or a mixture of hydrophobic particles and defoaming polymers; the thickener is at least one of pseudoplastic polyurethane thickener or Newtonian polyurethane thickener; the water-based silver paste is a coated water-based silver paste with a Dv50 particle size range of 5-50 μm and a non-volatile content of 50-80%.

7. The water-based motorcycle engine coating according to claim 1, characterized in that, The dispersant is selected from at least one of polyvinylpyrrolidone, vinylpyrrolidone, carboxymethyl cellulose, and sodium lignosulfonate; the cosolvent A and cosolvent B are each independently alcohol ether solvents; the neutralizing agent A and the neutralizing agent B are each independently selected from at least one of 2-amino-2-methyl-1-propanol, N,N-dimethylethanolamine, and triethylamine.

8. A method for preparing a water-based motorcycle engine coating according to any one of claims 1-7, characterized in that, The preparation method includes mixing a matrix resin, additives, colorants, and solvents to obtain the final product.

9. The method for preparing the water-based motorcycle engine coating according to claim 8, characterized in that, The preparation method of the water-based motorcycle engine coating includes: S1: Add the water-based silver paste to reactor A, then add cosolvent A and thickener and mix to obtain a paste. Soak for 1-2 hours and set aside. S2: Add water-based acrylic resin A to reactor B, and adjust the pH value to 7.5-8.5 by adding neutralizing agent A at a rotation speed of 500rpm-1000rpm. S3: Add water to reactor B and disperse for 5-10 minutes at a speed of 500-1000 rpm; S4: While dispersing, add leveling agent, substrate wetting agent and defoamer A into reactor B with a rotation speed of 500rpm-1000rpm, and disperse for 5-10 minutes under this condition; S5: While dispersing, add the amino resin and adhesion promoter to reactor B with a rotation speed of 500rpm-1000rpm, and disperse under this condition for 5-10min; S6: While dispersing the material in reactor A, add it to reactor B at a speed of 500 rpm-1000 rpm. After adding the material, continue to disperse it under these conditions for 5-10 minutes. S7: While dispersing, add the water-based pigment to reactor B at a rotation speed of 500 rpm-1000 rpm, and disperse under these conditions for 5-10 minutes; S8: Adjust the pH value to between 8.0 and 8.5 with neutralizing agent A, then disperse at 800 rpm to 1500 rpm for 20 to 30 minutes, and then filter to obtain the product.

Images