A waterborne one-component silver powder paint and a preparation method thereof

Abstract

The present application relates to a kind of water-based single-component silver powder paint and its preparation method.The water-based single-component silver powder paint described in the present application includes the following weight parts of raw materials: modified acrylic emulsion 50-70 parts, pure water 10-20 parts, neutralizing agent 0.2-0.5 parts, defoaming agent 0.2-0.5 parts, wetting agent 0.4-1 part, dispersing agent 0.2-1 part, water-based aluminum silver paste 5-10 parts, cosolvent 8-15 parts, thickening agent 1-2 parts;Among them, the modified acrylic emulsion is one or more of first modified acrylic emulsion, second modified acrylic emulsion;The first modified acrylic emulsion is the modified silane coupling agent monomer modified water-based acrylic emulsion obtained by using epoxy silane coupling agent and vinyl silane coupling agent through hydrolysis polycondensation reaction;The second modified acrylic emulsion is epoxy silane coupling agent modified water-based acrylic emulsion.The appearance, gloss and silver row effect of the coating film formed by the water-based single-component silver powder paint are excellent, and the adhesion, ethanol resistance, water boiling resistance and storage stability are excellent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water-based silver powder paint, in particular to a water-based single-component silver powder paint and a preparation method thereof. BACKGROUND

[0002] Water-based silver powder paint can be widely applied in the market fields of automobiles, household appliances and toys, etc., and plays a role of protection and decoration on the surface of substrates. At present, the water-based silver powder paint on the market has some deficiencies, such as poor ethanol resistance of two-component silver powder paint, applicability of amino baking paint silver powder paint to only high-temperature baking substrates, and high price of single-component polyurethane silver powder paint, which limits the development of silver powder paint.

[0003] CN101260269A discloses a water-based silver powder paint and a preparation method thereof. The water-based silver powder paint has strong adhesion, high temperature resistance and excellent corrosion resistance by mixing water-based acrylic emulsion and anticorrosive pigments and fillers. However, the water-based silver powder paint is applied in the field of high-temperature metal as an environmentally friendly anticorrosive coating, and is not applicable to the field of plastic paint.

[0004] CN102352157A discloses a chemical-resistant plastic paint, a use method and application thereof. The plastic paint has excellent chemical resistance and ethanol wiping resistance by using a mixed resin of thermoplastic acrylic resin, modified acrylic resin and ternary chlorovinyl acetate resin, and is obtained by electrostatic spraying. However, the application scheme uses a mixture of three different resins, which is complex in construction operation and increases the cost, and the ethanol wiping resistance is only 50 times, which is poor. SUMMARY

[0005] Therefore, the present application aims to provide a water-based single-component silver powder paint and a preparation method thereof. The water-based single-component silver powder paint can be applied to substrates such as plastic and metal, has strong applicability, does not need high-temperature baking, and the obtained paint film not only can maintain high gloss and excellent silver row effect, but also has excellent ethanol resistance, water boiling resistance and stable hot storage performance.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] A water-based single-component silver powder paint comprises the following raw materials by weight: modified acrylic emulsion 50-70 parts, pure water 10-20 parts, neutralizing agent 0.2-0.5 parts, defoaming agent 0.2-0.5 parts, wetting agent 0.4-1 part, dispersing agent 0.2-1 part, water-based aluminum silver paste 5-10 parts, cosolvent 8-15 parts, and thickening agent 1-2 parts.

[0008] The modified acrylic emulsion is one or more of a first modified acrylic emulsion and a second modified acrylic emulsion; the first modified acrylic emulsion is a water-based acrylic emulsion modified by a modified silane coupling agent monomer obtained through a hydrolysis and polycondensation reaction of an epoxy silane coupling agent and a vinyl silane coupling agent; and the second modified acrylic emulsion is a water-based acrylic emulsion modified by an epoxy silane coupling agent.

[0009] The first modified acrylic emulsion and the second modified acrylic emulsion both have excellent ethanol resistance, boiling water resistance and storage stability, and the appearance, gloss and silver row effect of the coating film formed by the water-based single-component silver powder paint are excellent, and the adhesion, ethanol resistance, boiling water resistance and storage stability are excellent. The first modified acrylic emulsion is obtained by chemical reaction of the epoxy silane coupling agent and the vinyl silane coupling agent, and the modified silane coupling agent monomer combines the excellent performance of each silane coupling agent and eliminates the active ethoxyl group. The water-based acrylic emulsion modified by the modified silane coupling agent monomer (i.e. the first modified acrylic emulsion) has excellent appearance, gloss and silver row effect of the coating film formed by the water-based single-component silver powder paint, and excellent adhesion, ethanol resistance, boiling water resistance and storage stability. In addition, the water-based acrylic emulsion modified by the epoxy silane coupling agent (i.e. the second modified acrylic emulsion) also has excellent ethanol resistance and boiling water resistance, and the appearance, gloss and silver row effect of the coating film formed by the water-based single-component silver powder paint are excellent, and the adhesion, ethanol resistance, boiling water resistance and storage stability are excellent.

[0010] In one embodiment, the neutralizing agent in the formula of the water-based single-component silver powder paint is an organic amine neutralizing agent. Preferably, the neutralizing agent is one or more of dimethyl ethanolamine and beta-amino isobutyl alcohol.

[0011] In one embodiment, the defoaming agent in the formula of the water-based single-component silver powder paint is a polysiloxane copolymer or a polyether siloxane copolymer defoaming agent. Preferably, the defoaming agent is selected from one or more of BYK-024 of BIK and Tego 902W of DEG. By adding a polysiloxane copolymer or a polyether siloxane copolymer type defoaming agent, the bubbles in the system are eliminated, and the dark bubbles of the formed paint film are reduced.

[0012] In one embodiment, the wetting agent in the formulation of the waterborne one-component silver powder paint is an organic silicon wetting agent. Preferably, the wetting agent is one or more of Degussa Tego 4100, Elementis Surfynol 104E. The addition of the organic silicon wetting agent reduces the surface tension of the waterborne one-component silver powder paint, making the waterborne one-component silver powder paint more easily wet the substrate, improving adhesion, and improving the application performance of the paint, such as leveling, orange peel, and other issues during application.

[0013] In one embodiment, the dispersing agent in the formulation of the waterborne one-component silver powder paint is a modified polyether or polycarboxylic acid dispersing agent. Preferably, the dispersing agent is one or more of Degussa Tego 755w, Pruf D-6086. The addition of the modified polyether or polycarboxylic acid dispersing agent reduces the surface tension of the wetted material, allowing the waterborne aluminum silver paste to be uniformly distributed in the waterborne one-component silver powder paint and to be uniformly dispersed during film formation.

[0014] In one embodiment, the waterborne aluminum silver paste in the formulation of the waterborne one-component silver powder paint is a solvent-coated or silica-coated waterborne aluminum silver paste. Preferably, the waterborne silver paste is one or more of Sel 7012, Sel 7006. Preferably, the waterborne aluminum silver paste is a silica-coated aluminum silver paste. Silica coating is a chemical coating method. From the appearance, the waterborne aluminum silver paste product produced by the silica coating method is relatively dry and fluffy. The silica-coated aluminum sheet has good dispersibility and is more reliable in combination with the system, has good compatibility, and does not damage the coating layer due to processing shear force during silver powder paint production, has good folding resistance, and eliminates the phenomenon of silver falling. The combination of silica and aluminum sheet is very tight, which does not reduce the gloss of the aluminum sheet surface, and has very outstanding acid and alkali resistance.

[0015] In one embodiment, the waterborne one-component silver powder paint formulation includes one or more of dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether as the co-solvent. Preferably, the co-solvent is one or more of Dowan DPNB, Dowan DE.

[0016] In one embodiment, the thickening agent in the formulation of the waterborne one-component silver powder paint is a polyether polyurethane associative or non-associative thickening agent. Preferably, the thickening agent is selected from one or more of Himin 299, Guanzhi ASE-60, and Borchs Gel PN. The addition of the polyether polyurethane associative or non-associative thickening agent increases the viscosity of the waterborne one-component silver powder paint, facilitating application, and also improves the anti-settling effect between the modified acrylic emulsion and the waterborne aluminum silver paste.

[0017] In an embodiment, the preparation method of the first modified acrylic emulsion comprises the following steps:

[0018] Preparation of modified silane coupling agent monomer: 20-60 parts of epoxy silane coupling agent, 20-60 parts of vinyl silane coupling agent and 1-3 parts of catalyst are added into a mixed solvent of 20-45 parts of isopropyl alcohol and 20-45 parts of pure water, and a modified silane coupling agent monomer is obtained through reaction;

[0019] Preparation of pre-emulsion A: 1-2 parts of emulsifier and 130-150 parts of pure water are added into an emulsification kettle and stirred and dissolved, and then 330-390 parts of acrylic monomer are added to obtain pre-emulsion A;

[0020] Preparation of pre-emulsion B: 0.1-0.4 parts of emulsifier, 0.1-0.2 parts of thermal initiator and 60-80 parts of pure water are added into an emulsification kettle and stirred and dissolved, and then 106-134 parts of acrylic monomer and 1-2 parts of molecular weight regulator are added to obtain pre-emulsion B;

[0021] Preparation of the first modified acrylic emulsion: after the temperature of the reaction kettle is raised to 80-90℃, 13-15 parts of pre-emulsion A is added as a seed, a mixture of 0.1-0.3 parts of thermal initiator and 1-3 parts of pure water is added, the remaining pre-emulsion A, pre-emulsion B and modified silane coupling agent monomer are added dropwise, respectively, after the dropwise addition is completed, the temperature is lowered, 1-2 parts of oxidation initiator, 0.5-1 parts of reduction initiator, 5-10 parts of self-crosslinking monomer, 10-30 parts of neutralizing agent and 2-4 parts of preservative are added, respectively, to obtain the first modified acrylic emulsion.

[0022] The preparation method of the first modified acrylic emulsion, through the chemical reaction of the epoxy silane coupling agent and the vinyl silane coupling agent, obtains the modified silane coupling agent monomer, which combines the excellent performance of each silane coupling agent, eliminates the active ethoxy group, and at the same time, uses the addition reaction of the olefin bond of the modified silane coupling agent monomer with the acrylic monomer to obtain the modified silane coupling agent monomer modified water-based acrylic emulsion, i.e. the first modified acrylic emulsion. The first modified acrylic emulsion has excellent appearance, gloss and silver row effect of the coating film formed in the silver powder paint, and excellent adhesion, ethanol resistance, water boiling resistance and storage stability.

[0023] In the step of preparing the modified silane coupling agent monomer, the epoxy silane coupling agent and the vinyl silane coupling agent can undergo hydrolysis and condensation reaction under the action of the catalyst, and by controlling the reaction amount of the two silane coupling agents, the generated modified silane coupling agent monomer can be free of active ethoxyl groups, eliminating the influence of hydrolysis and condensation reaction during storage, and improving the storage stability. In the reaction of preparing the modified silane coupling agent monomer, the reaction needs to undergo hydrolysis and condensation, and by adding a mixture of isopropyl alcohol and water, the active components can be more dispersed and less prone to caking. Since the epoxy silane coupling agent can increase the crosslinking density of the resin and improve the adhesion, and the vinyl silane coupling agent has good heat resistance and excellent chemical resistance, the two are chemically reacted to obtain the modified silane coupling agent monomer, so that the modified silane coupling agent monomer combines the excellent properties of each silane coupling agent, eliminates the active ethoxyl groups, improves the storage stability of the water-based acrylic emulsion, and also makes the water-based acrylic emulsion used in the silver powder paint form a coating film that is not affected by the introduction of the silane coupling agent in appearance, gloss, and silver row effect and other properties.

[0024] In the step of preparing the first modified water-based acrylic emulsion, the seed method is used to synthesize the first modified water-based acrylic emulsion. In the step of preparing the first modified acrylic emulsion, part of the pre-emulsion A is first added as a seed, and then further polymerization is carried out based on the seed, and the remaining pre-emulsion A, pre-emulsion B, and the modified silane coupling agent monomer are added dropwise, respectively, to catalytically synthesize the modified silane coupling agent monomer with the alkenyl groups and the acrylic monomer (or intermediate product) to form a stable water-based acrylic emulsion after modification, so that the modified water-based acrylic emulsion has excellent adhesion, ethanol resistance, and boiling water resistance and other properties.

[0025] In one embodiment, the second modified acrylic emulsion is Guanzhi PA-4757. Guanzhi PA-4757 is a water-based acrylic emulsion physically modified by a KH560 epoxy silane coupling agent, has excellent ethanol resistance, boiling water resistance, and storage stability, and is used in the water-based one-component silver powder paint to form a coating film with excellent appearance, gloss, and silver row effect, and excellent adhesion, ethanol resistance, boiling water resistance, and storage stability.

[0026] As a preferred scheme in the above-mentioned method for preparing the first modified acrylic emulsion, the reaction temperature in the step of preparing the modified silane coupling agent monomer is 40-60°C, and the reaction time is 4-6h. By controlling the reaction temperature at 40-60°C, the epoxy silane coupling agent and the vinyl silane coupling agent can undergo hydrolysis and condensation reaction under the action of the catalyst to generate the modified silane coupling agent monomer, eliminating the active ethoxyl groups.

[0027] As a preferred solution of the above-mentioned first method for preparing the modified acrylic emulsion, the epoxy silane coupling agent is one or more of epoxy triethoxysilane, methyl epoxy propyl ether diethoxysilane and dimethyl epoxy propyl ether ethoxysilane.

[0028] As a preferred solution of the above-mentioned first method for preparing the modified acrylic emulsion, the vinyl silane coupling agent is one or more of vinyl triethoxysilane, vinyl trimethoxysilane and methyl vinyl diethoxysilane.

[0029] As a preferred solution of the above-mentioned first method for preparing the modified acrylic emulsion, the catalyst is one or more of acetic acid, hydrochloric acid and p-toluene sulfonic acid. The use of an acidic catalyst is more conducive to the generation of the modified silane coupling agent monomer, making the reaction more stable.

[0030] As a preferred solution of the above-mentioned first method for preparing the modified acrylic emulsion, the reaction conditions for preparing pre-emulsion A are stirring at room temperature for emulsification; as a preferred solution, the reaction conditions for preparing pre-emulsion B are stirring at room temperature for emulsification.

[0031] As a preferred solution of the above-mentioned first method for preparing the modified acrylic emulsion, in the step of preparing pre-emulsion A and in the step of preparing pre-emulsion B, the emulsifier is one or more of alkyl sulfate sodium salt, alkyl sulfonate sodium salt and alcohol ether sulfate sodium salt.

[0032] As a preferred scheme of the preparation method of the first modified acrylic emulsion, in the preparation of pre-emulsion A step and in the preparation of pre-emulsion B step, the acrylic monomer includes hydrophobic acrylic monomer, hydrophilic acrylic monomer and self-crosslinkable acrylic monomer; the hydrophobic acrylic monomer is one or more of methyl methacrylate (MMA), styrene, n-butyl methacrylate, n-butyl acrylate, isooctyl acrylate (EHA), lauryl acrylate; the hydrophilic acrylic monomer can be selected from one or more of acrylic acid, methacrylic acid and β-acryloyloxy propionic acid (β-CEA); the self-crosslinkable acrylic monomer includes one or more of allyl methacrylate (AMA), glycidyl methacrylate, N-hydroxymethyl acrylamide, diacetone acrylamide (DAAM), ethylene glycol dimethacrylate. The acrylic monomers used in the preparation of pre-emulsion A step and in the preparation of pre-emulsion B step all contain hydrophobic acrylic monomers, hydrophilic acrylic monomers and self-crosslinkable acrylic monomers. The addition of the hydrophobic acrylic monomer can improve the water resistance, stability and other properties of the first modified acrylic emulsion; the hydrophilic acrylic monomer can increase the affinity and solubility of the first modified acrylic emulsion to water; and the self-crosslinkable acrylic monomer can improve the crosslinking density of the first modified acrylic emulsion.

[0033] As a preferred scheme of the preparation method of the first modified acrylic emulsion, in the 330-390 parts of acrylic monomers in the preparation of pre-emulsion A step: the amount of hydrophilic acrylic monomer is 10-20 parts, the amount of hydrophobic acrylic monomer is 310-350 parts, and the amount of self-crosslinkable acrylic monomer is 10-20 parts.

[0034] As a preferred scheme of the preparation method of the first modified acrylic emulsion, the self-crosslinkable acrylic monomer in the acrylic monomer in the preparation of pre-emulsion A step includes allyl methacrylate (AMA). The particle size of pre-emulsion A as seed is controlled through the action of AMA, thereby indirectly controlling the particle size of the acrylic emulsion.

[0035] As a preferred scheme of the preparation method of the modified acrylic emulsion, in the 106-134 parts of acrylic monomers in the preparation of pre-emulsion B step: the amount of hydrophilic acrylic monomer is 3-7 parts, the amount of hydrophobic acrylic monomer is 100-120 parts, and the amount of self-crosslinkable acrylic monomer is 3-7 parts.

[0036] As a preferred scheme of the preparation method of the first modified acrylic emulsion, the thermal initiator is one or more of ammonium persulfate and sodium persulfate;

[0037] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the molecular weight regulator is one or more of dodecyl mercaptan, mercaptopropionic acid, and AMSD.

[0038] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the oxidation initiator is added in the form of a mixture of the oxidation initiator and pure water, and the mixture contains 1-2 parts of the oxidation initiator and 10-20 parts of pure water. That is, in the step of preparing the first modified acrylic emulsion, 1-2 parts of the oxidation initiator is added in the form of a mixture of 1-2 parts of the oxidation initiator and 10-20 parts of pure water, and the mixture of the oxidation initiator and pure water is easier to disperse and react gently in the reaction kettle.

[0039] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the oxidation initiator is one or more of ammonium sulfate, sodium persulfate, and tert-butyl hydroperoxide (TBHP).

[0040] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the reduction initiator is added in the form of a mixture of the reduction initiator and pure water, and the mixture contains 0.5-1 parts of the reduction initiator and 40-80 parts of pure water. That is, in the step of preparing the first modified acrylic emulsion, 0.5-1 parts of the reduction initiator is added in the form of a mixture of 0.5-1 parts of the reduction initiator and 40-80 parts of pure water, and the concentration of the reduction initiator can be diluted. If the concentration of the reduction initiator is too high, the reaction will break emulsion.

[0041] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the reduction initiator is one or more of sodium bisulfite, sodium metabisulfite, and ascorbic acid.

[0042] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the neutralizing agent is one or more of ammonia and dimethyl ethanolamine. The pH of the aqueous acrylic emulsion is 7-8 by the action of the neutralizing agent. Preferably, the concentration of the ammonia is 12.5%, and low-concentration ammonia is used to avoid the appearance of gels.

[0043] As a preferred scheme of the above-mentioned first modified acrylic emulsion preparation method, the preservative can be one or more of Guanzhi BEK-200L and Guanzhi BEK-500Y. Other types of preservatives can also be selected by those skilled in the art.

[0044] As a preferred scheme of the preparation method of the first modified acrylic emulsion, the self-crosslinking monomer is added in the form of a mixture of the self-crosslinking monomer and pure water, and the mixture of the self-crosslinking monomer and pure water contains 5-10 parts of the self-crosslinking monomer and 15-32 parts of pure water. That is, in the step of preparing the first modified acrylic emulsion, 5-10 parts of the self-crosslinking monomer is added in the form of a mixture of 5-10 parts of the self-crosslinking monomer and 15-32 parts of pure water, and the self-crosslinking monomer and pure water are mixed to be easier to disperse in the reaction kettle and react mildly.

[0045] As a preferred scheme of the preparation method of the first modified acrylic emulsion, the self-crosslinking monomer is adipic acid dihydrazide (ADH).

[0046] As a preferred scheme of the preparation method of the modified acrylic emulsion, in the step of preparing the aqueous acrylic emulsion, in order to make the reaction more stable and mild, 3-7 parts of the emulsifier and 380-420 parts of pure water are first added to the reaction kettle, then the reaction kettle is raised to 80-90℃, and then 13-15 parts of the pre-emulsion A is added.

[0047] The application further provides a preparation method of the aqueous single-component silver powder paint, comprising the following steps:

[0048] The modified acrylic emulsion 50-70 parts, pure water 8-12 parts, neutralizing agent 0.2-0.5 parts, defoaming agent 0.2-0.5 parts, and wetting agent 0.4-1 part are added to container A and stirred uniformly to obtain a first mixture;

[0049] The pure water 2-8 parts, dispersant 0.2-1 part, and aqueous aluminum silver paste 5-10 parts are added to container B and stirred uniformly to obtain a second mixture;

[0050] The first mixture and the second mixture are mixed and stirred uniformly to obtain a third mixture; the cosolvent 8-15 parts and thickening agent 1-2 parts are added to the third mixture and stirred uniformly to obtain the aqueous single-component silver powder paint.

[0051] The aqueous single-component silver powder paint provided by the application uses at least one of the first modified acrylic emulsion and the second modified acrylic emulsion, so that the aqueous single-component silver powder paint can be applied to substrates such as plastic and metal, has strong applicability, does not need high-temperature baking, and the obtained paint film not only can maintain high gloss and has excellent silver row effect on the silver powder paint, but also has excellent ethanol resistance, water boiling resistance, and storage stability. DETAILED DESCRIPTION

[0052] The application is further described below in connection with examples. These examples are only used to illustrate the application and not to limit the scope of the application. The experimental methods in the following example embodiments are not specified, and are generally carried out according to conventional conditions or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, if not specifically stated, are commercially available raw materials and reagents.

[0053] In the examples 1-3, the first modified acrylic emulsion (see Table 1) is prepared according to the method of example 5.

[0054] Example 1

[0055] The example 1 provides a water-based single-component silver powder paint, the composition and content of each raw material in the formula are shown in Table 1.

[0056] The example 1 provides a preparation method of a water-based single-component silver powder paint, which comprises the following steps:

[0057] (1) 65 parts of modified acrylic emulsion, 10.4 parts of pure water, 0.2 parts of neutralizing agent, 0.2 parts of defoaming agent, and 0.7 parts of wetting agent are added to a clean container A, and stirred at 800 rpm for 5 min to obtain a first mixture;

[0058] (2) 6 parts of pure water, 6 parts of water-based aluminum silver paste, and 0.5 parts of dispersing agent are added to a clean container B and stirred uniformly to obtain a second mixture; the second mixture is added to container A and stirred at 600 rpm for 5 min;

[0059] (3) 10 parts of a co-solvent and 1 part of a thickening agent are added to container A and stirred at 600 rpm for 5 min to obtain the water-based single-component silver powder paint of the example 1.

[0060] The composition and content of each raw material used in the preparation method of the example 1 are shown in Table 1.

[0061] Example 2

[0062] The example 1 provides a water-based single-component silver powder paint, the composition and content of each raw material in the formula are shown in Table 1.

[0063] The preparation method of the water-based single-component silver powder paint of the example 1 is the same as that of the example 1; the specific composition and content of each raw material used in the preparation method of the example 1 are shown in Table 1.

[0064] Example 3

[0065] The example 1 provides a water-based single-component silver powder paint, the composition and content of each raw material in the formula are shown in Table 1.

[0066] The preparation method of the water-based single-component silver powder paint of the embodiment is the same as that of Example 1; wherein the specific composition and content of each raw material used in the preparation method of the embodiment are shown in Table 1.

[0067] Example 4

[0068] The embodiment provides a water-based single-component silver powder paint, and the composition and content of each raw material in the formula of the water-based single-component silver powder paint are shown in Table 1.

[0069] The preparation method of the water-based single-component silver powder paint of the embodiment is the same as that of Example 1; wherein the specific composition and content of each raw material used in the preparation method of the embodiment are shown in Table 1.

[0070] Table 1 Formula of the water-based single-component silver powder paint of Examples 1-3

[0071]

[0072] Example 5

[0073] The embodiment provides a first modified acrylic emulsion and a preparation method thereof.

[0074] The modified acrylic emulsion of the embodiment is prepared by the following preparation method:

[0075] S1: 30 g of isopropyl alcohol, 30 g of pure water and 2 g of p-toluenesulfonic acid are added to a reaction kettle, and after being heated to 50 DEG C, 40 g of dimethyl epoxy propyl ether group ethoxy silane and 20 g of methyl vinyl diethyl silane are added at a speed of one drop per second, and after being reacted for 4 h, a modified silane coupling agent monomer is obtained;

[0076] S2: 1.2 g of emulsifier SR-10 and 136 g of pure water are added to an emulsifying kettle and stirred, and after being dissolved, 15 g of beta-CEA, 300 g of MMA, 20 g of AMA, 26 g of EHA and 13 g of DAAM are added respectively, and after being emulsified to white and uniform and not layered, a pre-emulsion A is obtained;

[0077] S3: 0.4 g of emulsifier SR-10, 0.1 g of ammonium persulfate and 66 g of pure water are added to an emulsifying kettle and stirred and dissolved, and then 5 g of beta-CEA, 100 g of MMA, 10 g of EHA, 4 g of DAAM and 1 g of n-dodecyl mercaptan are added respectively and emulsified, and after being emulsified to milky white and not layered, a pre-emulsion B is obtained.

[0078] S4: 5 g of emulsifier CA120 and 400 g of pure water were added into a reaction kettle, and then the temperature was raised to 85°C. After that, 14 g of pre-emulsion A was added as a seed, and then a mixture of 0.25 g of ammonium persulfate and 2.5 g of pure water was added. After 15 min of reaction, the remaining pre-emulsion A was added dropwise into the reaction kettle, and the dropwise addition was performed for 2 h. After the dropwise addition was completed, the temperature was kept for 0.5 h. Then, pre-emulsion B was added dropwise into the reaction kettle at the end of the temperature keeping, and a modified silane coupling agent monomer was added dropwise at the same time. The dropwise addition was performed for 0.5 h, and the temperature was kept for 0.5 h. After the temperature keeping was completed, the temperature of the reaction kettle was reduced to 65°C, and a mixture of 0.7 g of TBHP and 7 g of pure water was added. Then, a mixture of 0.5 g of ascorbic acid and 40 g of pure water was added dropwise for 0.5 h, and the temperature was kept for 0.5 h. After the temperature keeping was completed, the temperature was reduced to 50°C, and 20 g of ammonia water (12.5%), a mixture of 8 g of ADH and 25 g of pure water, and 3 g of preservative BEK-200L were added into the reaction kettle, respectively. After stirring for 10 min, the product was filtered through a 200-mesh filter bag to obtain a first modified acrylic emulsion of this example, which was used in Examples 1-3.

[0079] Comparative Example 1

[0080] This comparative example provides a water-based one-component silver powder paint. The composition and content of each raw material in the formula are shown in Table 2.

[0081] The preparation method of the water-based one-component silver powder paint of this comparative example includes the following steps:

[0082] (1) 65 parts of a water-based acrylic emulsion, 10.4 parts of pure water, 0.2 parts of a neutralizing agent, 0.2 parts of a defoaming agent, and 0.7 parts of a wetting agent were added into a clean container A, and stirred at 800 rpm for 5 min to obtain a first mixture;

[0083] (2) 6 parts of pure water, 6 parts of a water-based aluminum silver paste, and 0.5 parts of a dispersing agent were added into a clean container B and stirred uniformly to obtain a second mixture. The second mixture was added into container A, and stirred at 600 rpm for 5 min;

[0084] (3) 10 parts of a cosolvent and 1 part of a thickening agent were added into container A, and stirred at 600 rpm for 5 min to obtain the water-based one-component silver powder paint of this comparative example.

[0085] The composition and content of each raw material used in the preparation method of this comparative example are shown in Table 2.

[0086] Comparative Example 2

[0087] This comparative example provides a water-based one-component silver powder paint. The composition and content of each raw material in the formula are shown in Table 2.

[0088] The preparation method of the water-based single-component silver powder paint of the present comparative example comprises the following steps:

[0089] (1) 65 parts of water-based polyurethane dispersion, 10.4 parts of pure water, 0.2 parts of neutralizing agent, 0.2 parts of defoaming agent, and 0.7 parts of wetting agent were added into a clean container A, stirred at 800 rpm for 5 min to obtain a first mixture;

[0090] (2) 6 parts of pure water, 6 parts of water-based aluminum silver paste, and 0.5 parts of dispersing agent were added into a clean container B and stirred uniformly to obtain a second mixture; the second mixture was added into container A and stirred at 600 rpm for 5 min;

[0091] (3) 10 parts of cosolvent and 1 part of thickening agent were added into container A and stirred at 600 rpm for 5 min to obtain the water-based single-component silver powder paint of the present comparative example.

[0092] The composition and content of each raw material used in the preparation method of the present comparative example are shown in Table 2.

[0093] Comparative Example 3

[0094] The present comparative example provides a water-based single-component silver powder paint, and the composition and content of each raw material in the formula are shown in Table 2.

[0095] The preparation method of the water-based single-component silver powder paint of the present comparative example comprises the following steps:

[0096] (1) 65 parts of water-based polyurethane dispersion, 10.4 parts of pure water, 0.2 parts of neutralizing agent, 0.2 parts of defoaming agent, and 0.7 parts of wetting agent were added into a clean container A, stirred at 800 rpm for 5 min to obtain a first mixture;

[0097] (2) 6 parts of pure water, 6 parts of water-based aluminum silver paste, and 0.5 parts of dispersing agent were added into a clean container B and stirred uniformly to obtain a second mixture; the second mixture was added into container A and stirred at 600 rpm for 5 min;

[0098] (3) 10 parts of cosolvent and 1 part of thickening agent were added into container A and stirred at 600 rpm for 5 min to obtain the water-based single-component silver powder paint of the present comparative example.

[0099] The composition and content of each raw material used in the preparation method of the present comparative example are shown in Table 2.

[0100] Table 2 Formula of water-based single-component silver powder paint of comparative examples 1-3

[0101]

[0102]

[0103] The waterborne one-component silver powder paint of Examples 1-4 and Comparative Examples 1-3 was respectively added with an appropriate amount (20-30 wt%) of pure water to adjust the viscosity to a suitable value (wherein Comparative Example 3 needs to be added with isocyanate curing agent and then adjusted with pure water to adjust the viscosity) and then sprayed on an ABS substrate. The baking conditions of the paint film were 70°C / 2h, and the baked paint film was tested as follows:

[0104] Silver bar effect: visual appearance.

[0105] Hardness: According to GB / T 6739-2006b standard, the hardness of the paint film was tested, and the rating was 9B-F-9H, with 9B being the softest and 9H being the hardest.

[0106] Gloss test: The 60° gloss of the paint film was tested using the British RHOPOINT gloss meter NOVO-GLOSS.

[0107] L value test: The L value of the paint film was tested using the Japanese KONIC MINOLTA colorimeter CR-10Plus.

[0108] Adhesion test: According to GB / T 9286-2021 standard, the paint film was subjected to grid test, and the rating was 0-5 levels, with 0 being the best and 5 being the worst.

[0109] Alcohol resistance: The paint film was subjected to alcohol resistance using a standard rubber alcohol dual-purpose rubbing tester, with a weight of 500g, and the number of times was recorded until the paint film fell through.

[0110] Boiling water test: The sprayed and dried substrate was placed in a constant temperature water bath at 80°C for 2h, and the changes in the paint film before and after boiling were observed.

[0111] Storage stability: The prepared paint sample was placed at 50°C for 7 days, and the gloss, L value and alcohol resistance of the paint film were tested.

[0112] The performance test results are shown in Tables 3 and 4.

[0113] Table 3 Waterborne one-component silver powder paint test results

[0114]

[0115]

[0116] Table 4 Waterborne one-component silver powder paint (after hot storage) test results

[0117] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Film thickness / μm 12 12 12 12 12 12 12 Silver streak effect Good Good Good Good Fair Fair Fair Hardness F F F F F F F 60° gloss / ° 63.1 63.4 63.9 62.1 60.2 61.3 60.6 L value 87.1 87.4 86.1 85.3 82.2 83.2 82.8 Adhesion 0 level 0 level 0 level 0 level 0 level 0 level 0 level Resistance to ethanol wiping > 500 times > 500 times > 500 times 180 times 70 times 6 times 32 times Boiling in 80°C water >2h >2h >2h >2h <1h <0.5h <1h

[0118] The above results show that the water-based single-component silver powder paint of embodiments 1-4 prepared by using the first modified acrylic emulsion and / or the second modified acrylic emulsion (Guangzhi PA-4757) of embodiment 5 has excellent silver row effect, and also has excellent ethanol resistance and boiling water resistance; and the water-based single-component silver powder paint of embodiments 1-4 has little difference in various performances after 50℃ / 7d heat storage, has excellent heat storage stability, and has certain application value. The water-based single-component silver powder paint prepared by using the water-based acrylic emulsion, the water-based polyurethane dispersion, and the water-based two-component hydroxypropyl dispersion in Comparative Examples 1-3 has poor ethanol resistance, boiling water resistance, and heat storage, and is inferior to the water-based single-component silver powder paint in the application, thereby limiting the production and application range.

[0119] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and the present application also intends to include these modifications and improvements.

Claims

1. An aqueous, one-component silver powder paint, characterized by: The raw materials include the following weight parts: modified acrylic emulsion 50-70 parts, pure water 10-20 parts, neutralizing agent 0.2-0.5 parts, defoaming agent 0.2-0.5 parts, wetting agent 0.4-1 part, dispersing agent 0.2-1 part, water-based aluminum silver paste 5-10 parts, cosolvent 8-15 parts, thickening agent 1-2 parts; The modified acrylic emulsion is a first modified acrylic emulsion; the preparation method of the first modified acrylic emulsion comprises the following steps: Preparation of modified silane coupling agent monomer: 20-60 parts of epoxy silane coupling agent, 20-60 parts of vinyl silane coupling agent and 1-3 parts of catalyst are added to a mixed solvent of 20-45 parts of isopropyl alcohol and 20-45 parts of pure water, and a modified silane coupling agent monomer is obtained after reaction; Preparation of pre-emulsion A: 1-2 parts of emulsifier, 130-150 parts of pure water are added to an emulsifying kettle and stirred and dissolved, and then 330-390 parts of acrylic monomer are added to obtain pre-emulsion A; Preparation of pre-emulsion B: 0.1-0.4 parts of emulsifier, 0.1-0.2 parts of thermal initiator and 60-80 parts of pure water are added to an emulsifying kettle and stirred and dissolved, and then 106-134 parts of acrylic monomer and 1-2 parts of molecular weight regulator are added to obtain pre-emulsion B; Preparation of first modified acrylic emulsion: after the temperature of the reaction kettle is raised to 80-90 DEG C, 13-15 parts of pre-emulsion A is added as a seed, a mixture of 0.1-0.3 parts of thermal initiator and 1-3 parts of pure water is added, the remaining pre-emulsion A, pre-emulsion B and modified silane coupling agent monomer are added dropwise, respectively, after the dropwise addition is completed, the temperature is lowered, 1-2 parts of oxidation initiator, 0.5-1 parts of reduction initiator, 5-10 parts of self-crosslinking monomer, 10-30 parts of neutralizing agent and 2-4 parts of preservative are added, respectively, to obtain the first modified acrylic emulsion.

2. The waterborne, one-component silver powder paint according to claim 1, characterized in that The neutralizing agent is an organic amine neutralizing agent; the defoaming agent is a polysiloxane copolymer or a polyether siloxane copolymer defoaming agent; the wetting agent is an organic silicon wetting agent; the dispersing agent is a modified polyether type or a polycarboxylic acid type dispersing agent; the water-based aluminum silver paste is a solvent-coated or silica-coated water-based aluminum silver paste; the cosolvent is one or more of dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether and propylene glycol methyl ether; the thickening agent is a polyether polyurethane associated type or a non-associated type thickening agent.

3. The waterborne, one-component silver powder paint according to claim 1, characterized in that: The epoxy silane coupling agent is one or more of epoxy triethoxysilane, methyl epoxy propyl ether diethoxysilane and dimethyl epoxy propyl ether ethoxysilane; the vinyl silane coupling agent is one or more of vinyl triethoxysilane, vinyl trimethoxysilane and methyl vinyl diethoxysilane.

4. The waterborne, one-component silver powder paint according to claim 1, characterized in that: In the preparation of pre-emulsion A step and the preparation of pre-emulsion B step, the acrylic monomer includes hydrophobic acrylic monomer, hydrophilic acrylic monomer and self-crosslinkable acrylic monomer; the hydrophobic acrylic monomer is one or more of methyl methacrylate, styrene, n-butyl methacrylate, n-butyl acrylate, iso-octyl acrylate, lauryl acrylate; the hydrophilic acrylic monomer is one or more of acrylic acid, methacrylic acid and β-acryloyloxypropionic acid; the self-crosslinkable acrylic monomer includes one or more of allyl methacrylate, glycidyl methacrylate, N-hydroxymethyl acrylamide, diacetone acrylamide, ethylene glycol dimethacrylate.

5. The waterborne, one-component silver powder paint according to claim 4, characterized in that In 330-390 parts of acrylic monomer in the preparation of pre-emulsion A step, the amount of hydrophilic acrylic monomer is 10-20 parts, the amount of hydrophobic acrylic monomer is 310-350 parts, and the amount of self-crosslinkable acrylic monomer is 10-20 parts.

6. The waterborne, one-component silver powder paint according to claim 4, characterized in that: In 106-134 parts of acrylic monomer in the preparation of pre-emulsion B step, the amount of hydrophilic acrylic monomer is 3-7 parts, the amount of hydrophobic acrylic monomer is 100-120 parts, and the amount of self-crosslinkable acrylic monomer is 3-7 parts.

7. The waterborne, one-component silver powder paint according to claim 1, characterized in that: In the preparation method of the first modified acrylic emulsion, the catalyst is one or more of acetic acid, hydrochloric acid and p-toluenesulfonic acid; the emulsifier is one or more of alkyl sulfate sodium salt, alkyl sulfonate sodium salt and alcohol ether sulfate sodium salt; the thermal initiator is one or more of ammonium persulfate and sodium persulfate; the molecular weight regulator is one or more of dodecyl mercaptan, mercaptopropionic acid and AMSD; the oxidation initiator is one or more of ammonium sulfate, sodium persulfate and tert-butyl hydroperoxide; the reducing initiator is one or more of sodium bisulfite, sodium metabisulfite and ascorbic acid; the neutralizing agent is one or more of ammonia and dimethyl ethanolamine; the self-crosslinking monomer is ADH; the preservative is one or more of Guanzhi BEK-200L and Guanzhi BEK-500Y.

8. A process for the preparation of an aqueous one-component silver powder paint according to any one of claims 1 to 7, characterized in that It includes the following steps: Put 50-70 parts of modified acrylic emulsion, 8-12 parts of pure water, 0.2-0.5 parts of neutralizing agent, 0.2-0.5 parts of defoaming agent and 0.4-1 parts of wetting agent into container A and stir uniformly to obtain a first mixture; Put 2-8 parts of pure water, 0.2-1 parts of dispersant and 5-10 parts of water-based aluminum silver paste into container B, stir uniformly to obtain a second mixture; Mix the first mixture and the second mixture, stir uniformly to obtain a third mixture; add 8-15 parts of cosolvent and 1-2 parts of thickening agent to the third mixture, stir uniformly to obtain the water-based single-component silver powder paint.

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