Two-component boiling-resistant switch paint as well as preparation method and application thereof

Abstract

The invention provides two-component boiling-resistant switch paint as well as a preparation method and application thereof. Comprising the following raw materials in parts by weight: 11-15 parts of a water-based hydroxyl acrylic acid dispersion emulsion, 15-45 parts of a water-based polyurethane dispersion, 5-8 parts of water-based aluminum paste, 3-10 parts of a silver bar auxiliary agent, 2-4 parts of a coalescing agent, 2-5 parts of a functional additive and the balance of deionized water; the component B is prepared from the following components in parts by weight: 3.25 to 6.75 parts of epoxy siloxane modified isocyanate curing agent and 1.75 to 2.25 parts of diluent; wherein in the epoxy silane modified isocyanate curing agent, the mass of epoxy silane accounts for 1.5 to 4.0 percent of the mass of isocyanate; the sum of the parts of the component A and the component B is 100. According to the invention, the isocyanate curing agent is modified and interacts with the water-based hydroxyl acrylic acid dispersion, so that the boiling resistance and ethanol wiping resistance of a cured paint film are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, in particular to a two-component water-boiling resistant switch paint and its preparation method and application. Background Art

[0002] With the increasingly strict environmental protection standards, traditional solvent-based coatings are gradually being phased out due to the presence of volatile organic compounds (VOCs). Especially in the coating applications in the fields of daily switches, household appliances, automotive parts, etc., environmental protection issues are particularly important. Daily switches usually use composite materials such as ABS, ABC+PC, etc. as substrates. Traditional coating methods usually use solvent-based aluminum silver paste coatings to endow the coating with a metallic luster effect. However, the VOC emissions of solvent-based coatings have imposed a great burden on the environment. Therefore, a water-based silver powder coating has emerged and is widely used due to its excellent adhesion, water-boiling resistance, chemical resistance, salt spray resistance and flexibility.

[0003] The dispersibility of water-based aluminum silver paste in water-based coatings and the arrangement requirements of silver powder are relatively high. To avoid the phenomenon of "yin-yang surface" in the coating, the coating is required to have good pseudoplasticity, thixotropy and construction performance. Although the current water-based silver powder coatings can meet the environmental protection requirements, their performance often cannot fully reach the above high standards, especially in terms of water-boiling resistance, chemical resistance, salt spray resistance, etc., and there are still certain technical bottlenecks.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings in the prior art, and in view of the deficiencies of traditional water-based silver powder coatings in terms of adhesion, water-boiling resistance, chemical resistance, salt spray resistance and construction performance, to provide a brand-new two-component water-boiling resistant switch paint.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect of the present invention, a two-component water-boiling resistant switch paint is provided, which comprises the following raw materials in parts by weight:

[0008] Component A:

[0009] 11-15 parts of water-based hydroxyl acrylic dispersion emulsion, 15-45 parts of water-based polyurethane dispersion, 5-8 parts of water-based aluminum silver paste, 3-10 parts of silver arrangement aid, 2-4 parts of film-forming aid, 2-5 parts of functional additive, and the balance is deionized water;

[0010] Component B:

[0011] 3.25 - 6.75 parts of epoxy group siloxane modified isocyanate curing agent and 1.75 - 2.25 parts of diluent; among them, in the epoxy group silane modified isocyanate curing agent, the mass of the epoxy group silane accounts for 1.5 - 4.0% of the mass of the isocyanate;

[0012] The total of component A and component B is 100 parts.

[0013] In the present invention, by modifying the isocyanate curing agent and acting together with the aqueous hydroxyl acrylic dispersion, the boiling water resistance of the cured paint film is improved. Specifically:

[0014] The modified isocyanate curing agent contains a bicyclic structure, namely an aliphatic isocyanurate ring and the epoxy group in the silane; the natural chair configuration (or bowl configuration) of the epoxy group has high steric stability, and this configuration enables the molecules of the cyclic structure to avoid spatial conflicts with each other and maintain a low energy state; the siloxane group in the silane has hydrophobicity and plays a role in preventing water penetration in the cross-linked network of the coating. When the coating is exposed to high-temperature water, the siloxane group will form a hydrophobic barrier to reduce the contact between water and the internal structure of the coating, thereby improving the water resistance; the structure of the isocyanurate ring is stable and has good chemical resistance, thermal stability, wear resistance, and corrosion resistance. The three groups act together to significantly improve the high-temperature boiling water resistance of the cured paint film.

[0015] After the mixing of component A and component B, the isocyanate in component B will cross-link with the hydroxyl group in component A to form a tough three-dimensional network structure, enhancing the mechanical properties of the paint film; the co-action between the bicyclic structure in the isocyanate and the aqueous hydroxyl acrylic dispersion can further improve the uniformity of the distribution of cross-linking points and further enhance the high-temperature boiling water stability of the paint film.

[0016] Preferably, the epoxy group siloxane modified isocyanate curing agent is prepared by a method including the following steps: in an inert atmosphere, the reaction monomers of isocyanate, epoxy group siloxane, and polyether diol are mixed uniformly in water, and then reacted at 50 - 60 °C. After the isocyanate group in the reaction system reaches 14 - 23% of the theoretical value, a polymerization inhibitor is added to terminate the reaction, and thus the epoxy group silane modified isocyanate curing agent can be obtained.

[0017] It should be noted that in the above reaction system, -Si-O- can undergo hydrolysis reaction to emulsify or dissolve the reaction monomers of isocyanate in water. At the same time, the hydroxyl groups in polyether diol react with -Si-OH after the hydrolysis of siloxane and -NCO in the reaction monomers of isocyanate, combining epoxy group siloxane and isocyanate together. Specifically: The Si-O bond in epoxy group siloxane undergoes hydrolysis under the action of water to generate silanol groups (-Si-OH); the hydrolyzed silanol groups are hydrophilic, which helps to emulsify or dissolve the isocyanate monomers in the water phase; the hydroxyl groups in polyether diol undergo condensation reaction with the hydrolyzed silanol groups to form Si-O-Si bonds, enhancing the cross-linking degree of the polymer; the hydrolyzed silanol groups react with the -NCO groups in the isocyanate monomers to form silamino compounds, combining epoxy group siloxane and isocyanate together. This multi-step reaction process enables epoxy group siloxane to effectively react with waterborne isocyanate, improving the adhesion, weather resistance and chemical resistance of the coating.

[0018] In the present invention, the di-n-butylamine titration method is used to determine the amount of isocyanate group (-NCO) in the above reaction system.

[0019] Preferably, the inert atmosphere includes an atmosphere formed by at least one gas among nitrogen, helium and argon.

[0020] Preferably, the molecular weight of the polyether diol is 400 - 800. The mass ratio of the polyether diol to the epoxy group silane is 1:(3.3 - 5.5).

[0021] Preferably, the polymerization inhibitor includes at least one of benzoyl chloride and phosphoric acid.

[0022] Preferably, the epoxy group siloxane includes at least one of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)methyldiethoxysilane, poly[dimethylsiloxane-co-(2-(3,4-epoxycyclohexyl)ethyl)methylsiloxane].

[0023] Preferably, the reaction monomers of the isocyanate include at least one of HDI trimer (hexamethylene diisocyanate trimer), IPDI trimer (isophorone diisocyanate), HDI-TDI trimer (hexamethylene diisocyanate-toluene diisocyanate trimer), IPDI-TDI trimer (isophorone diisocyanate-toluene diisocyanate trimer).

[0024] Preferably, the hydroxyl - containing aliphatic aqueous polyurethane dispersion has a hydroxyl content in the range of 3 - 4.5% in the aqueous hydroxyl - acrylic acid dispersion emulsion. The aqueous hydroxyl - acrylic acid with a hydroxyl content in this range can form a secondary dispersion with good dispersion performance, significantly improving the high - temperature boiling water resistance and chemical resistance of the cured paint film, especially the ethanol - wiping resistance.

[0025] Preferably, the aqueous polyurethane dispersion is an aliphatic aqueous polyurethane dispersion with a hydroxyl content in the range of 0.5 - 2%. It can act together with the aqueous hydroxyl - acrylic acid dispersion emulsion and the epoxy - group - modified isocyanate curing agent to improve the dispersion uniformity of the cross - linking points of the paint film, and thus significantly improve the high - temperature boiling water resistance of the cured paint film.

[0026] Preferably, the mass ratio of the aqueous hydroxyl - acrylic acid dispersion emulsion to the aqueous polyurethane dispersion is 1:(1 - 3).

[0027] Preferably, the diluent includes at least one of propylene glycol diacetate (PGDA), propylene glycol methyl ether acetate (PMA), and dipropylene glycol dimethyl ether (DMM). The diluent is a small - molecule poly - functional alcohol ester substance, which can not only adjust the viscosity of the curing system, but also control the curing speed of the paint film and improve the adhesion to the substrate. Using the above diluents of the present invention can further improve the adhesion to the substrate.

[0028] Preferably, the film - forming aid includes at least one of dipropylene glycol methyl ether, dipropylene glycol butyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, and tripropylene glycol monobutyl ether.

[0029] Preferably, the silver - discharging aid includes at least one of ethylene - vinyl acetate copolymer wax emulsion and high - density polyethylene wax emulsion.

[0030] In the present invention, some functional additives can also be added as needed to endow corresponding functions, and common functional additives in the art can be used in the present invention. For example, it includes at least one of cosolvents, defoamers, rheology modifiers, and wetting agents.

[0031] Optionally, the cosolvent includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and propylene glycol tert - butyl ether.

[0032] Optionally, the defoamer includes at least one of ether - type defoamers, silicone - ether defoamers, and fumed silica.

[0033] Optionally, the rheology modifier includes but is not limited to polyurea.

[0034] Optionally, the wetting agent includes, but is not limited to, anionic wetting agents, non-ionic wetting agents, etc. The anionic wetting agent includes, but is not limited to, at least one of sulfate esters (such as sodium dodecyl sulfate), sulfonate esters (such as sodium alkylbenzene sulfonate), phosphate esters (such as alkyl phosphate esters), carboxylates (such as fatty acid soaps). The non-ionic wetting agent includes, but is not limited to, at least one of fatty alcohol polyoxyethylene ethers, fatty acid polyoxyethylene esters, polyoxyethylene alkylamines, poly(dimethylsiloxane) polyoxyethylene ethers.

[0035] In a second aspect of the present invention, there is provided a method for preparing the two-component water-resistant switch paint described in the first aspect of the present invention, comprising the following steps: according to the weight parts, after mixing the components in component A and the raw materials in component B evenly respectively, the two-component water-resistant switch paint can be obtained.

[0036] Common mixing means in the art can be used to prepare the two-component water-resistant switch paint in the present invention, for example, it can be stirring, ultrasonic, oscillation, etc.

[0037] In a third aspect of the present invention, there is provided the application of the two-component water-resistant switch paint described in the first aspect of the present invention. The two-component water-resistant switch paint is applied to household electrical appliances and automotive parts.

[0038] It should be noted that in the present invention, when the two-component water-resistant switch paint is applied, it is necessary to mix component A and component B before curing to form a film and play a role.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] By modifying the isocyanate curing agent and acting together with the aqueous hydroxyl acrylic dispersion, the present invention improves the water-boiling resistance and ethanol wiping resistance of the cured paint film. Specific Embodiments

[0041] To better illustrate the purpose, technical solution and advantages of the present invention, the following will further illustrate the present invention with specific embodiments, but the embodiments do not impose any form of limitation on the present invention. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0042] Some raw materials used in the embodiments of the present invention are listed as follows:

[0043] Aqueous hydroxyl acrylic dispersion emulsion - 1: hydroxyl content is 3.3%, WPA4407, purchased from Huigu;

[0044] Aqueous hydroxyl acrylic dispersion emulsion - 2: hydroxyl content is 3.9%, 2470, purchased from Covestro, Germany;

[0045] Waterborne hydroxyl acrylic dispersion emulsion - 3: Hydroxyl content is 3.03%, Luhydran S 938T, purchased from BASF;

[0046] Waterborne polyurethane dispersion - 1: Hydroxyl content is 1.9%, U 2757, purchased from Covestro, Germany;

[0047] Waterborne polyurethane dispersion - 2: Hydroxyl content is 1.1%, UAPOLY 2511, purchased from Guangzhou Lianggu New Materials;

[0048] Waterborne polyurethane dispersion - 3: Hydroxyl content is 1.4%, DB2561, purchased from Double Bond New Materials;

[0049] Waterborne polyurethane dispersion - 4: Hydroxyl polycarbonate - type polyurethane dispersion, hydroxyl content is 3.9%, U XP 2750, purchased from Covestro, Germany;

[0050] Waterborne aluminum silver paste: 3304, purchased from Shenzhen Mantebo Waterborne Nanomaterials Technology Co., Ltd.;

[0051] Silver - discharging aid 1: Ethylene - vinyl acetate copolymer wax emulsion (EVA wax emulsion), BYK - 8421, purchased from BYK, Germany;

[0052] Silver - discharging aid 2: EVA wax emulsion, 227B, purchased from Longhai Chemical Industry;

[0053] Film - forming aid 1: Dipropylene glycol methyl ether, commercially available;

[0054] Film - forming aid 2: Triethylene glycol monoethyl ether, commercially available;

[0055] Co - solvent: Ethylene glycol monomethyl ether, commercially available;

[0056] Defoamer: Polyether - silicone copolymer, 902w, purchased from Degussa, Germany;

[0057] Rheology modifier: Polyurea, BYK - 420, purchased from BYK, Germany;

[0058] Wetting agent: Sodium dodecyl sulfate, commercially available;

[0059] Diluent: Propylene glycol diacetate (PGDA), commercially available;

[0060] 1# Epoxy - group - modified isocyanate curing agent is prepared by the following method:

[0061] Under nitrogen protection, 90 parts of hexamethylene diisocyanate trimer (HDI Trimer, molecular weight 504.58) were added to a reaction kettle, and the temperature was raised to 50 °C. A mixed solution of 2 parts of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (molecular weight 246.4) and 11 parts of polyethylene glycol monomethyl ether (molecular weight 800) was added dropwise to the system containing hexamethylene diisocyanate trimer within 60 min, and the reaction was carried out for 6 hours to reach the theoretical NCO value. 0.2 part of the polymerization inhibitor benzoyl chloride was added to terminate the reaction, and thus a modified curing agent was obtained. The NCO content was 20.8%, the solid content was 100%, and the viscosity (25 °C) was 6000 mPa·s.

[0062] The 2# epoxy group siloxane modified isocyanate curing agent is prepared by the following method:

[0063] Under nitrogen protection, 97 parts of isophorone diisocyanate trimer (IPDI Trimer, molecular weight 666) were added to a reaction kettle, and the temperature was raised to 60 °C. A mixed solution of 1.5 parts of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane (molecular weight 288.5) and 5 parts of polypropylene glycol (molecular weight 600) was added dropwise to the isocyanate system within 30 min, and the reaction was carried out for 5 hours to reach the theoretical NCO value. 0.5 part of the polymerization inhibitor phosphoric acid was added to terminate the reaction, and thus a modified curing agent was obtained. The NCO content was 17.2%, the solid content was 100%, and the viscosity (25 °C) was 7500 mPa·s.

[0064] The 3# epoxy group siloxane modified isocyanate curing agent is prepared by the following method:

[0065] Under nitrogen protection, 45 parts of hexamethylene diisocyanate trimer (HDITrimer molecular weight 504.58) and 45 parts of isophorone diisocyanate (molecular weight 666) were successively added to a reaction kettle, and the temperature was raised to 55 °C. A mixed solution of 1.5 parts of 2-(3,4-epoxycyclohexyl)methyldiethoxysilane (molecular weight 258.429) and 8 parts of polyethylene glycol monomethyl ether (molecular weight 700) was added dropwise to the isocyanate system within 45 min, and the reaction was carried out for 8 hours to reach the theoretical NCO value. 0.3 part of the polymerization inhibitor benzoyl chloride was added to terminate the reaction, and thus a modified curing agent was obtained. The NCO content was 17%, the solid content was 100%, and the viscosity (25 °C) was 6300 mPa·s.

[0066] The 4# epoxy group siloxane modified isocyanate curing agent is prepared by the following method:

[0067] Under nitrogen protection, 80 parts of hexamethylene diisocyanate trimer (HDI trimer, molecular weight: 504.58) was heated to 55 °C, and a mixture of 2.5 parts of poly[dimethylsiloxane-co-(2-(3,4-epoxycyclohexyl)ethyl)methylsiloxane] (x = 1, y = 1, molecular weight 417) and 10 parts of polyethylene glycol monomethyl ether (molecular weight 500) was added dropwise to the isocyanate system within 20 min and reacted for 7 hours to reach the theoretical NCO value. Then, 0.6 part of inhibitor phosphoric acid was added to terminate the reaction, and a silane-modified aqueous isocyanate curing agent was obtained. The NCO content was 22.8%, the solid content was 100%, and the viscosity (25 °C) was 5500 mPa·s;

[0068] The structural formula of poly[dimethylsiloxane-co-(2-(3,4-epoxycyclohexyl)ethyl)methylsiloxane] is as follows, x = 1, y = 1, and the molecular weight is 417:

[0069]

[0070] Examples 1 to 15

[0071] A series of two-component water-boiling resistant switch paints were provided and prepared by a method including the following steps:

[0072] According to the formulations (parts by weight) described in Table 1 and Table 2, after each component in component A and each raw material in component B were mixed evenly respectively (the total weight of component A and component B was 100 parts), the two-component water-boiling resistant switch paint could be obtained.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077]

[0078] Comparative Example 1

[0079] A two-component water-boiling resistant switch paint was provided and prepared with reference to the components and method of Example 1. The difference from Example 1 was that in component B, the isocyanate curing agent was not modified, that is:

[0080] The epoxy group-containing siloxane-modified isocyanate curing agent was replaced with an equal weight of hexamethylene diisocyanate trimer (HDI Trimer, molecular weight 504.58).

[0081] Comparative Example 2

[0082] A two-component water-boiling resistant switch paint is provided. It is prepared with reference to the components and method of Example 1. The difference from Example 1 is that in Component B, only silicone is used to modify the isocyanate curing agent, and the modifier does not contain epoxy groups, that is:

[0083] In the process of preparing the "No. 1 epoxy group siloxane modified isocyanate curing agent", 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (molecular weight 246.4) is replaced with an equal weight portion of γ-aminopropyltriethoxysilane.

[0084] Comparative Example 3

[0085] A two-component water-boiling resistant switch paint is provided. It is prepared with reference to the components and method of Example 1. The difference from Example 1 is that in Component B, only epoxy groups are used to modify the isocyanate curing agent, and the modifier does not contain silicone, that is:

[0086] In the process of preparing the "No. 1 epoxy group siloxane modified isocyanate curing agent", 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (molecular weight 246.4) is replaced with an equal weight portion of an epoxy intermediate, and the epoxy intermediate is prepared as follows: Under the action of nitrogen protection, condensation reflux and mechanical stirring, 5.70 g (0.02 mol) of ethylene glycol diglycidyl ether (EGDE) and 10.00 mL of N,N-dimethylformamide (DMA) are placed in a 500 mL four-necked flask, and the temperature is maintained at 20 °C. Then, a 5.00 mL DMA solution containing 1.50 g (0.02 mol) of N-methylethanolamine (DMEA) is added to the flask through a constant pressure dropping funnel, and the temperature is maintained at 25 °C for 30 min to obtain the epoxy intermediate.

[0087] Comparative Example 4

[0088] A two-component water-boiling resistant switch paint is provided. It is prepared with reference to the components and method of Example 1. The difference from Example 1 is that in Component B, the "No. 1 epoxy group siloxane modified isocyanate curing agent" is replaced with an equal weight portion of "a mixture obtained by mixing hexamethylene diisocyanate trimer, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and polyethylene glycol monomethyl ether (molecular weight 800) in a mass ratio of 90:2:11", that is, no chemical modification is carried out, but physical mixing is performed.

[0089] Comparative Example 5

[0090] A two-component water-boiling resistant switch paint is provided. It is prepared with reference to the components and method of Example 1. The difference from Example 1 is that in Component A, the aqueous polyurethane dispersion Replace U 2757 with an equal mass of "aminopolysiloxanyl 4,5-epoxytetrahydrophthalic diglycidyl ester cyclic carbonate"; at the same time, select the unmodified isocyanate curing agent "hexamethylene diisocyanate trimer (HDI Trimer, molecular weight 504.58)" in component B;

[0091] Among them, aminopolysiloxanyl 4,5-epoxytetrahydrophthalic diglycidyl ester cyclic carbonate is prepared by the following method: Add the 4,5-epoxytetrahydrophthalic diglycidyl ester cyclic carbonate compound into a round-bottom flask, add dimethylformamide (DMF) accounting for 30% of the mass of the 4,5-epoxytetrahydrophthalic diglycidyl ester cyclic carbonate compound, add aminopolysiloxane (number-average molecular weight 3000) accounting for 0.5% of the mass of the 4,5-epoxytetrahydrophthalic diglycidyl ester cyclic carbonate compound, the reaction temperature is 120 °C, and react for 6 h to obtain aminopolysiloxanyl 4,5-epoxytetrahydrophthalic diglycidyl ester cyclic carbonate.

[0092] Application performance test

[0093] Mix the A and B components of the two-component water-boiling resistant switch paint in the above-mentioned examples and comparative examples evenly, and then coat them on the surface of the ABS substrate. After baking at 5 °C for 30 min, a coating with a thickness of 15 ± 2 μm is formed. The following performance tests are carried out on these coatings:

[0094] (1) Water-boiling resistance:

[0095] Refer to the cross-cut method in the standard "ASTM D3359-2017" to measure the adhesion between the coating and the substrate before and after high-temperature water boiling respectively. It is divided into 6 grades from 5B to 0B, with 5B being the best and 0B being the worst; among them, the conditions for high-temperature water boiling are: boil in boiling water at 100 °C for 2 h, and then soak in a constant-temperature water bath at 80 °C for 24 h.

[0096] (2) Ethanol wiping resistance:

[0097] Refer to the standard "ASTM D4752-2024". Specifically: Drop 99.7% concentration alcohol on 4 layers of clean white cotton cloth, load a 500 g weight, and wipe on the coating surface. One round trip left and right is counted as one time, and record the maximum number of wiping times when "the paint film is not damaged and there is no staining on the cotton cloth". The test results are shown in Table 3.

[0098] Table 3 Performance test results

[0099]

[0100] It can be seen from the above results that:

[0101] The two-component water-boiling resistant switch paint prepared by the present invention, after curing into a film, has good adhesion between the coating and the substrate, all above 5B. After being boiled in boiling water and at 80 °C for a high temperature, the adhesion retention rate with the substrate can reach more than 80%, significantly superior to the comparative examples. At the same time, it also has excellent ethanol-resistant wiping performance, and the number of ethanol-resistant wiping times is all above 80 times.

[0102] In Comparative Example 1, an unmodified isocyanate curing agent was used; the curing agent modifier in Comparative Example 2 did not contain an epoxy group; the curing agent modifier in Comparative Example 3 did not contain silicone; in Comparative Example 4, the curing agent modifier and isocyanate were only physically mixed; in the final coating of Comparative Example 5, although it also contained an epoxy group and silicone, they were not connected to the isocyanate; the changes in the above components all led to the interaction between the components during the coating curing process, thereby resulting in a poor dispersion uniformity of the components in the coating, and further resulting in a significant deterioration of the water-boiling resistance of the final coating.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A two-component water-resistant switch paint, characterized in that Comprising the following raw materials in parts by weight: Component A: 11 - 15 parts of aqueous hydroxyl acrylic dispersion emulsion, 15 - 45 parts of aqueous polyurethane dispersion, 5 - 8 parts of aqueous aluminum silver paste, 3 - 10 parts of silver discharge aid, 2 - 4 parts of film-forming aid, 2 - 5 parts of functional additive, with the balance being deionized water; Component B: 3.25 - 6.75 parts of epoxy group siloxane modified isocyanate curing agent, 1.75 - 2.25 parts of diluent; wherein, in the epoxy group silane modified isocyanate curing agent, the mass of the epoxy group silane accounts for 1.5 - 4.0% of the mass of the isocyanate; The total of Component A and Component B is 100 parts.

2. The two-component water-resistant switch paint according to claim 1, characterized in that, The epoxy group silane modified isocyanate curing agent is prepared by a method comprising the following steps: In an inert atmosphere, the reaction monomers of isocyanate, epoxy group siloxane, and polyether diol are mixed evenly in water, and then reacted at 50 - 60 °C. After the isocyanate group in the reaction system reaches 14 - 23% of the theoretical value, a polymerization inhibitor is added to terminate the reaction, thus obtaining the epoxy group silane modified isocyanate curing agent.

3. The two-component water-boiling resistant switch paint according to claim 2, wherein The epoxy group siloxane in the epoxy group silane modified isocyanate curing agent includes at least one of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 2-(3,4-epoxycyclohexyl)methyldiethoxysilane, poly[dimethylsiloxane-co-(2-(3,4-epoxycyclohexyl)ethyl)methylsiloxane].

4. The two-component water-boiling resistant switch paint according to claim 2, characterized in that, The reaction monomers of the isocyanate include at least one of HDI trimer, IPDI trimer, HDI-TDI trimer, IPDI-TDI trimer.

5. The two-component water-boiling resistant switch paint according to claim 1, wherein The hydroxyl content of the aqueous hydroxyl acrylic dispersion emulsion is 3 - 4.5%.

6. The two-component water-resistant switch paint according to claim 1, wherein The hydroxyl content of the aqueous polyurethane dispersion is 0.5 - 2%.

7. The two-component water-resistant switch paint according to claim 1, characterized in that, Meeting at least one of the following characteristics: (1) The silver discharge aid includes at least one of ethylene-vinyl acetate copolymer wax emulsion, high-density polyethylene wax emulsion; (2) The film-forming aid includes at least one of dipropylene glycol methyl ether, dipropylene glycol butyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tripropylene glycol monobutyl ether; (3) The diluent includes at least one of propylene glycol diacetate, propylene glycol methyl ether acetate, dipropylene glycol dimethyl ether.

8. The two-component water-boiling resistant switch paint according to claim 1, wherein The functional additive includes at least one of cosolvent, defoamer, rheology aid, wetting agent.

9. The preparation method of the two-component water-boiling resistant switch paint according to any one of claims 1 to 8, characterized in that, Comprising the following steps: According to the said parts by weight, each component in Component A and each raw material in Component B are respectively mixed evenly, thus obtaining the two-component water-boiling resistant switch paint.

10. Use of the two-component water-resistant switch paint according to any one of claims 1 to 8, characterized in that, The two-component water-boiling resistant switch paint is applied to household electrical appliances and automotive parts.

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