1. The two-component water-based epoxy silver paint is characterized by comprising a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 40-70% of aqueous epoxy resin dispersoid, 4-8% of liquid epoxy resin, 2-6% of anti-sagging resin, 10-20% of lithium magnesium sodium silicate solution, 10-20% of passivated aluminum paste and 0.5-6% of auxiliary agent; the curing agent comprises the following components in percentage by weight: 40-60% of fatty amine additive, 3-5% of cosolvent, 0.3-3% of auxiliary agent and the balance of deionized water.

2. The two-component waterborne epoxy silver paint of claim 1, wherein the weight percentage of the aqueous epoxy resin dispersion in the A component is 45-65%.

3. The two-component waterborne epoxy silver paint of claim 2, wherein the weight percentage of the aqueous epoxy resin dispersion in the a component is 50%.

4. The two-component aqueous epoxy silver paint according to claim 1, wherein at least one of the following (a) to (f):

(a) the main agent aqueous epoxy resin dispersoid is a modified solid bisphenol A nonionic epoxy resin dispersoid;

(b) the liquid epoxy resin is bisphenol A/F liquid epoxy resin, the epoxy equivalent is 150-250 g/mol, the dynamic viscosity is 9000-13000 mPa & s, and the flash point is more than 100 ℃;

(c) the anti-sagging resin is core-shell pseudoplastic acrylic emulsion, the solid content of the anti-sagging resin is 20-32%, the acid value is 2-10 mg KOH/g, and the hydroxyl value is 20-40 mg KOH/g;

(d) the lithium magnesium silicate sodium solution is composed of lithium magnesium sodium silicate, polypropylene glycol and deionized water, and the mass ratio of the lithium magnesium sodium silicate to the polypropylene glycol to the deionized water is as follows: polypropylene glycol: deionized water 2-4: 1: 94-97.5;

(e) the auxiliary agent in the auxiliary agent is at least one of a wetting agent, a defoaming agent, a silane coupling agent, an anti-flash rust auxiliary agent, a corrosion inhibitor and a surface control agent;

(f) the passivated aluminum paste is composed of ethylene glycol hexyl ether, amino resin, oily aluminum powder and an aluminum powder passivating agent, and the mass ratio of the ethylene glycol hexyl ether to the amino resin to the oily aluminum powder to the aluminum powder passivating agent is 1-2: 0.2-0.5: 1: 0.3 to 0.5.

5. The two-component aqueous epoxy silver paint according to claim 1, wherein at least one of the following (a) to (e):

(a) the solid content of the aliphatic amine addition compound in the curing agent is 45-65%, and the amine value is 150-300 mg/KOH;

(b) the cosolvent in the curing agent is DPNB and PM, and the mass ratio of the DPNB to the PM is (1-2): 1;

(c) the auxiliary agents in the curing agent are a defoaming agent and a thickening agent;

(d) the defoaming agent is an emulsion defoaming agent;

(e) the thickening agent is a polyurethane thickening agent.

6. The two-component water-based epoxy silver paint as claimed in claim 1, wherein the weight ratio of the main agent to the curing agent is 3-5: 1.

7. The preparation method of the two-component water-based epoxy silver paint as claimed in any one of claims 1 to 6, which is characterized by comprising the following steps:

(1) sequentially adding the aqueous epoxy resin dispersoid, the liquid epoxy resin and the anti-sagging resin under stirring in proportion, and uniformly dispersing to obtain a mixed solution a; preparing a lithium magnesium sodium silicate solution according to a proportion; preparing passivated aluminum paste according to a proportion; adding a lithium magnesium sodium silicate solution and passivated aluminum paste into the mixed solution a, and uniformly dispersing; sequentially adding an auxiliary agent and deionized water, uniformly dispersing, and obtaining a main agent after qualified detection;

(2) adding the fatty amine addition product according to a certain proportion, stirring, dispersing the cosolvent, the auxiliary agent and the deionized water into the fatty amine addition product, and uniformly stirring to obtain the curing agent;

(3) and mixing the main agent and the curing agent in proportion, and uniformly stirring to obtain the double-component water-based epoxy silver paint.

8. The use of the two-component waterborne epoxy silver paint according to any one of claims 1 to 7 in substrate coating.

Background

The two-component epoxy has the advantages of strong adhesive force, excellent corrosion resistance, good water resistance, high hardness and the like, and is widely applied to the fields of containers, engineering machinery, rail transit, automobile parts and the like. The development of epoxy coatings is receiving more and more attention. But in the current market, the paint is widely applied to solvent type double-component epoxy paint. With the enhancement of environmental protection consciousness and the driving of national policies, the waterborne coating has low VOC content, high flash point and low smell, and is popular in the market. The development of a water-based epoxy coating with good workability and excellent performance is the most important of the prior art.

Patent CN102627905 discloses a waterborne epoxy anticorrosive paint, which comprises a component A and a component B, wherein the component B is an AB-HGF waterborne epoxy curing agent, has high viscosity (about 10000 mPa.s), is not diluted, is inconvenient to operate during use, is difficult to be uniformly mixed with the component A, has an activation period of less than or equal to 2h, and is difficult to meet the requirements of customers. Patent CN100558835 discloses a two-component water-based epoxy anticorrosive paint, wherein the epoxy curing agent is polyamide 650 and alcohol ether solvent, the mass percentages are 58-62% and 38-42%, respectively, and the curing agent contains a large amount of solvent; and a large amount of bubbles are generated when the epoxy curing agent is stirred and dissolved, and the epoxy curing agent cannot be canned in time, so that the production efficiency is reduced. Therefore, it is necessary to develop a curing agent process which has moderate viscosity, low VOC content and can be canned instantly.

With the continuous improvement of the living standard of people, people have higher pursuit of colors, and gradually favor of the flashing paint with special metallic luster. The flashing paint has a metallic flashing effect with a color variation with angle. The decorative effect of the flash paint is that the paint is added with aluminum powder or pearl powder and other effect pigments, so the appearance is beautiful. The solvent-based silver paint has low solid content and high viscosity, and needs to add a large amount of Organic solvent in construction application, and releases VOC (volatile Organic compounds) to pollute air. However, the oily aluminum powder cannot be used directly in an aqueous system, and there are problems of coarsening and poor storage stability. The poor storage stability is mainly caused by the fact that the aluminum paste slowly reacts with water in an aqueous system to generate hydrogen gas, so-called 'gassing' phenomenon appears, which is expressed by the expansion of a packaging barrel and is dangerous when the packaging barrel is opened. At present, the water-based aluminum paste is modified on the surface of oily aluminum powder. The main method for modification is to use SiO2 for coating to prevent gas evolution, and the Hydrolan series of Eckart is popular in the market. However, the manufacturing cost of the aqueous aluminum paste is quite high, and the aqueous aluminum paste is mainly applied to automobile original factory paint and automobile refinishing paint, so that the application range of the aqueous aluminum paste is greatly limited.

There are also some treatments of oily aluminum powder to enable its use in aqueous systems. Chinese patent CN101429319 discloses a water-based baking aluminum powder paint and a preparation method thereof, wherein the method for treating oily aluminum powder in the invention is prepared by mixing 50-70% by weight of oily aluminum paste and 30-50% by weight of alcohol or ether or ester; chinese patent CN107955494 discloses a preparation method of water-based epoxy hammer paint, in the method for treating oily aluminum powder in the invention, water-based epoxy resin, a dispersant, a wetting assistant and deionized water are added into a system, high-speed stirring is carried out, then a cosolvent and a thixotropic agent are added, and color paste, a thickening agent and aluminum powder are added. The two methods can improve the stability of the oily aluminum paste in a water-based system, but the storage time is less than 2 months, and the industrial use is far from being met. In addition, in order to improve the dispersibility of the oily aluminum powder in an aqueous system, a dispersing agent is introduced, so that the water resistance and the salt spray resistance of a paint film are greatly influenced.

At present, a physical method is mainly used for passivating the oily aluminum paste. Chinese invention CN101289581 has disclosed a preparation method of polystyrene resin coating type aluminium paste, adopt the mean of polymerization in situ to coat the even dense transparent polystyrene resin layer on the surface of aluminium paste, the glossiness of the aluminium paste is good after coating, the adhesive force is improved; however, the polystyrene resin and the aluminum paste are unstable under the action of high shear, which causes the polystyrene resin layer to fall off from the surface of the aluminum paste, and the protective effect of the polystyrene resin layer is lost. Patent CN101760071 discloses a method for using solvent type resin aluminum pigment in water-based paint, which mainly uses epoxy phosphate ester resin containing phosphate ester group and hydroxyl group to treat oily aluminum paste, the process is simple, and the storage stability is improved; however, the number average molecular weight control range of the epoxy phosphate used is 1500-3000, the molecular weight is small, the ability of inhibiting the diffusion of water molecules is weak, and the weatherability of the epoxy phosphate is poor. Therefore, it is important to develop a passivation method with less influence on the glossiness of the aluminum powder and good storage stability.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides the two-component epoxy water-based silver paint with good sagging resistance, high gloss, good weather resistance and salt spray resistance and good storage stability, and the preparation method and the application thereof.

In order to achieve the purpose, the invention adopts the technical scheme that: the two-component water-based epoxy silver paint comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 40-70% of aqueous epoxy resin dispersoid, 4-8% of liquid epoxy resin, 2-6% of anti-sagging resin, 10-20% of lithium magnesium sodium silicate solution, 10-20% of passivated aluminum paste and 0.5-6% of auxiliary agent; the curing agent comprises the following components in percentage by weight: 40-60% of fatty amine additive, 3-5% of cosolvent, 0.3-3% of auxiliary agent and the balance of deionized water.

The invention improves the stability and the weather resistance of the oily aluminum paste on the premise of ensuring the glossiness and the flicker degree of the oily aluminum paste; the water-based system has low VOC content, no pungent smell and low price, can greatly reduce the price of the water-based two-component epoxy aluminum powder paint and expand the application range of the water-based two-component epoxy aluminum powder paint; the viscosity of the curing agent is moderate after treatment, the curing agent is stirred at high speed without bubbles and can be packaged immediately; the main agent and the curing agent have good mixing compatibility, better construction performance, easy manual stirring and long activation period; the paint system has good sagging resistance, high gloss, and good weather resistance and salt spray resistance.

As a preferred embodiment of the two-component water-based epoxy silver paint, the weight percentage of the water-based epoxy resin dispersoid in the main agent is 40-70%. More preferably, the weight percentage of the aqueous epoxy resin dispersion in the main agent is 45-65%.

As a preferred embodiment of the two-component water-based epoxy silver paint, the aqueous epoxy resin dispersion in the main agent is a solid bisphenol A nonionic epoxy resin dispersion.

Researches show that the modified solid bisphenol A nonionic epoxy resin dispersoid has the characteristics of excellent shear resistance, quick drying, good adhesion to various substrates, high gloss, good combination property with different pigments (comprising aluminum powder and pearl powder), good physical and mechanical properties, good weather resistance, water resistance, excellent salt spray resistance and the like. The resin plays a key role in the performance of a paint film and the metal effect of the aluminum paste. Aqueous epoxy resin dispersions suitable for the present invention may be synthesized according to methods well known in the art or may be obtained commercially. Commercially available aqueous epoxy resin dispersions suitable for the present invention include, but are not limited to, those available under the tradename EPIKOTE 3523-WH-53 from spain corporation.

As a preferred embodiment of the two-component water-based epoxy silver paint, the liquid epoxy resin is bisphenol A/F liquid epoxy resin, the epoxy equivalent is 150-250 g/mol, the dynamic viscosity is 9000-13000 mPa & s, and the flash point is more than 100 ℃; the anti-sagging resin is core-shell pseudoplastic acrylic emulsion, the solid content of the anti-sagging resin is 20-32%, the acid value is 2-10 mg KOH/g, and the hydroxyl value is 20-40 mg KOH/g; the lithium magnesium sodium silicate solution is composed of lithium magnesium sodium silicate, polypropylene glycol and deionized water, and the mass ratio of the lithium magnesium sodium silicate to the polypropylene glycol is 2-4: 1: 94-97.5; the auxiliary agent in the main agent is at least one of a wetting agent, a defoaming agent, a silane coupling agent, an anti-flash rust auxiliary agent, a corrosion inhibitor and a surface control agent; the passivated aluminum paste is composed of ethylene glycol hexyl ether, amino resin, oily aluminum powder and an aluminum powder passivating agent, and the mass ratio of the ethylene glycol hexyl ether to the amino resin to the oily aluminum powder to the aluminum powder passivating agent is 1-2: 0.2-0.5: 1: 0.3 to 0.5.

Studies have shown that the high crosslink density of 100% solids bisphenol a/F liquid epoxy resin can adjust the water resistance, chemical resistance, abrasion resistance, salt spray resistance, and the like of the paint film. Because the resin has high viscosity and is difficult to disperse, the resin needs to be added at the rotating speed of 800-. Liquid epoxy resins suitable for the present invention may be synthesized according to methods well known in the art or may be obtained commercially. Commercially available liquid epoxy resins suitable for the present invention include, but are not limited to, those commercially available under the trade designation Beckopox EP 147w from Zhan Xin Co.

Research shows that the core-shell pseudoplastic acrylic emulsion has strong pseudoplastic property after neutralization, so that the viscosity of the system is increased under the action of static and low shearing force, and the anti-settling effect is particularly obvious; when in construction, the coating can reduce the viscosity of the system under the action of high shear; when the coating particles are attached to the workpiece, the viscosity is increased; therefore, the addition of the core-shell pseudoplastic acrylic emulsion ensures the atomization and leveling of the system, but simultaneously avoids the sagging phenomenon. The pseudoplasticity of the pseudoplastic resin facilitates the orientation arrangement of the aluminum powder. The pseudoplastic resin is sensitive to pH, so in order to ensure the stability of the viscosity of the system, the pH control range is as narrow as possible, and the preferred pH range is 6.4-7.8. Core-shell pseudoplastic acrylic emulsions suitable for use in the present invention may be synthesized according to methods well known in the art or may be obtained commercially. Commercially available core-shell pseudoplastic acrylic emulsions suitable for the present invention include, but are not limited to, those available under the tradename SeTAQUA 6803 from Zhanxin.

Studies have shown that commercially available lithium magnesium silicate sodium salts suitable for the present invention are commercially available including, but not limited to LAPONITE RD from byk. LAPONITE RD is a synthetic sheet silicate having a solubility of 2.8g in water and which, when hydrated, swells to a colorless transparent gel. When the concentration is 3%, colloid with high thixotropy can be formed through hydrogen bonds, and when high shear is performed, the hydrogen bonds are opened due to applied acting force, the viscosity is diluted instantly, and when coating particles are applied to a workpiece, the viscosity is increased due to small shearing force. The thixotropy of the acrylic emulsion is the same as that of the pseudoplastic acrylic emulsion, thereby being beneficial to the directional arrangement of aluminum powder. The addition of polypropylene glycol is beneficial to the stability of the lithium magnesium silicate sodium salt in water, and can improve the storage stability of the lithium magnesium silicate sodium salt. Polypropylene glycols suitable for the present invention may be synthesized according to methods well known in the art or may be obtained commercially. Commercially available polypropylene glycols suitable for the present invention include, but are not limited to, PPG-400 from Dawson. The preparation method of the lithium magnesium silicate sodium salt solution comprises the steps of adding deionized water into a moving tank according to the formula proportion, starting stirring until the rotating speed is 400-600 rpm, continuously and slowly adding the lithium magnesium silicate sodium salt, then adjusting the rotating speed to 1000-1500 rpm, and continuously dispersing for about 60 min.

Studies have shown that wetting agents of the acetylenic diols and derivatives thereof tend to provide excellent dynamic surface tension and that wetting agents of the organosiloxane type tend to provide excellent static surface tension. Since the wetting of the aqueous epoxy resin is poor compared to that of polyurethane, the substrate wetting agent of the present invention is preferably an organosiloxane-based wetting agent, and particularly, polyether-modified organosilane is preferred; humectants suitable for the present invention are commercially available and include, but are not limited to, BYK-348 and the like from the Bick company; in order to improve the adhesion of a paint film on a base material and the salt fog resistance, a silane coupling agent can be added into the system, the hydrolysis speed of the silane coupling agent is selected from a functional group Si-X, and the reactivity of the silane coupling agent and an organic polymer is selected from a functional group C-Y. Therefore, it is important to select a suitable silane coupling agent for different substrates or treatment objects. The method of selection is primarily pre-selected by experimentation and should be performed on the basis of pre-existing experience or rules. Through a large number of experiments, silane coupling agents suitable for epoxy resin are selected from silane coupling agents containing CH2-CHCH 2O-and H2N-and the wetting agent suitable for the invention can be obtained from commercial sources, can be purchased from Bike company such as A-187 of Michigan company, and the mass percent of the wetting agent is preferably 0.5-1.5%.

The flash rust prevention auxiliary agent can prevent flash rust caused by slow volatilization of water during construction of the water-based paint. In particular, when the substrate is a carbon steel plate, the flash rusting phenomenon is more likely to occur. Flash rust belongs to an electrochemical phenomenon and is related to the temperature, humidity and pH of a construction environment. Flash rust can affect the overall appearance of the paint film and can result in a substantial reduction in mechanical properties. Commercially available flash rust inhibitors suitable for use in the present invention are preferably ASCODAN-H14 and ASCONIUM-142DA from Ascopdy. ASCODAN-H14 is a high-film-forming-property liquid type flash rust prevention auxiliary agent, is easy to add, good in compatibility and stable in storage, gives consideration to hydrophobicity and excellent flash rust prevention property, can be immediately adsorbed to the surface of metal after being coated, and is small in dosage, preferably 0.3-0.8% in percentage by mass, and more preferably 0.4-0.6%. The ASCONIUM-142DA has hydrophobicity, can increase the water resistance of a coating, has excellent adhesive force, does not influence the gloss of a paint film, and is preferably 0.5-1.5% in mass percent.

The aluminum powder passivator in the passivated aluminum paste of the component A consists of ethylene glycol hexyl ether, phosphoric acid modified polystyrene and DMEA, and the mass ratio of the ethylene glycol hexyl ether to the phosphoric acid modified polystyrene to the DMEA is (35-50): (50-65): 1. in order to improve the stability of the oily aluminum paste in a water-based system and simultaneously give consideration to the metal luster and texture of the oily aluminum paste, the invention adopts phosphoric acid modified styrene as a passivating agent. The phosphoric acid-modified styrene suitable for the present invention can be synthesized according to a method known in the art, or obtained commercially, and the phosphoric acid-modified styrene of the present invention is self-made by a company of actual creation, and its actual creation number is WC 32. The weight-average molecular weight of the phosphoric acid modified polystyrene is 5000-10000, the solid content is 50-70%, and the acid value is 25-50 mgKOH/g. Because the phosphoric acid modified styrene is acidic, the phosphoric acid modified styrene is neutralized by DMEA to improve the water solubility, and the ethylene glycol hexyl ether is used for adjusting the viscosity to improve the operability. The invention carries out a great deal of research on the dispersion wetting agent and the stability of the oily aluminum paste by using a hydrophilic solvent, wherein the hydrophilic solvent comprises ethanol, IPA (isopropanol), n-butanol, isobutanol, isooctanol, DPM (dipropylene glycol methyl ether), BCS (ethylene glycol butyl ether), ethylene glycol hexyl ether, PPM (propylene glycol phenyl ether), DMM (dipropylene glycol dimethyl ether), DPNB (dipropylene glycol n-butyl ether), PM (propylene glycol methyl ether), PNB (propylene glycol n-butyl ether), PMA (propylene glycol methyl ether acetate), PGDA (propylene glycol diacetate), BGA (ethylene glycol butyl ether acetate), diethylene glycol butyl ether and the like. The ethylene glycol hexyl ether has the minimum influence on the directional arrangement of the aluminum powder, can have stronger swelling effect on the pseudoplastic acrylic acid solution, better shows the pseudoplastic property of the pseudoplastic acrylic acid solution and ensures that the coating system has better sag resistance. The addition amount of the ethylene glycol hexyl ether is 1-2 times of the mass of the aluminum powder, and the addition amount of the passivating agent is 30-50% of the mass of the aluminum powder. The method for treating the oily aluminum paste comprises the following steps: adding ethylene glycol hexyl ether and amino resin according to the formula amount, starting stirring, then adding oily aluminum paste, fully stirring for 30-60min, continuously adding an aluminum powder passivator, continuously dispersing for 60-120 min, completing the passivation of the oily aluminum paste, and placing the passivated aluminum paste for 12-16 hours before use. The addition amount of the aluminum powder passivator is adjusted according to the particle size of the aluminum powder, and the larger the particle size is, the smaller the addition amount is. It was found that the addition of a small amount of amino resin was advantageous for the wrapping and wetting of aluminum powder, and no difference was detected in storage stability and paint film properties and properties. The addition amount of the amino resin is 20-50% of the mass of the aluminum powder. Amino resins suitable for the present invention may be synthesized according to methods well known in the art or may be obtained commercially. Commercially available amino resins suitable for the present invention include, but are not limited to, Enlish amino resin Resimene HM-2608.

As a preferred embodiment of the two-component water-based epoxy silver paint, the solid content of the aliphatic amine adduct in the curing agent is 45-65%, and the amine value is 150-300 mg/KOH; the cosolvent in the curing agent is DPNB and PM; the auxiliary agents in the curing agent are a defoaming agent and a thickening agent; the defoaming agent is an emulsion defoaming agent; the thickening agent is a polyurethane thickening agent.

The research shows that after the curing agent of the amidated polyamine (mainly polyamine and C18 fatty acid polycondensation product) and the polyamide (mainly polyethylene polyamine and C36 dimer acid polycondensation product), the chemical resistance and the water resistance of the paint film are poor, and the reaction speed is slow. The epoxy resin modified polyamine has water solubility and good compatibility with epoxy resin, is easy to obtain the solubilizing effect on the epoxy resin, and is beneficial to improving the stability and the uniformity of a paint film. The commonly used amine comprises aliphatic, alicyclic and aromatic polyamines (ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine and diethylaminopropylamine), and after the amine is modified by epoxy, the reaction activity of the aromatic polyamine addition product is slightly low, while the reaction activity of the aliphatic polyamine addition product is higher, so that the amine can be crosslinked at room temperature. The invention preferably selects the aliphatic amine adduct curing agent, the solid content is 45-65%, the amine value is 150-300mg/KOH, and the active hydrogen equivalent is 180-550 g/mol. The mass percentage of the resin in the total weight of the component B is preferably 40-60%. The aliphatic amine adduct curing agents suitable for the present invention may be synthesized according to methods well known in the art or may be obtained commercially. Commercially available aliphatic amine adduct curatives suitable for this invention are commercially available and include, but are not limited to, Epikure 8545-W-52 from Vast.

Research shows that the defoaming agent can be divided into three categories, namely emulsion type defoaming agent, solution type defoaming agent and concentrated type defoaming agent, the emulsion type defoaming agent has the advantages that the defoaming agent is well dispersed into small liquid drops with defoaming effect through emulsification, so that the defoaming agent can be directly used and quickly takes effect without being ground when in use, is convenient to use and can be added at any stage, the incompatibility between the defoaming agent and a system can be adjusted by adjusting the content of hydrophilic parts in a silicone oil structure, and the defoaming agent has lower surface tension so as to achieve the purpose of defoaming. The emulsion type defoaming agent has great advantages in the aspect of eliminating micro bubbles, and is particularly suitable for defoaming of a high-viscosity aqueous system. The component B is the defoaming agent, so that the problem that the canning of production is influenced and the production efficiency is reduced due to the foaming caused by high-speed stirring during the dispersion of the curing agent is solved. The commercially available antifoaming agent suitable for the present invention is preferably an emulsion type antifoaming agent Airex902W available from Digao corporation, preferably 0.3 to 1% by mass, more preferably 0.4 to 0.7% by mass. Compatibility is considered, defoaming efficiency is considered, and instant canning can be achieved.

Researches show that the type of the thickening agent is alkali swelling type, polyurethane type and the like, the thickening agent can increase the viscosity of a system and also has a certain anti-settling effect; the alkali swelling thickener is sensitive to the pH value, and the thickening effect is obvious when the pH value is higher than 8.0; the epoxy system is generally very weak in alkalinity, and the pH is generally less than 7.5, so through experimental research, the alkali swelling thickener is not suitable for the epoxy system, and the water resistance and the salt spray resistance of a paint film are influenced. The invention selects polyurethane thickener which is not sensitive to pH and has no influence on the system tolerance. The thickening agent plays a role in the curing agent, on one hand, the viscosity of the curing agent is improved, and the hydrophobic curing agent is prevented from being settled to cause unevenness and influence on use; on the other hand, when the main agent portion and the curing agent portion are mixed, the viscosity is lowered (even if the viscosity of the main agent and the viscosity of the curing agent are high). Therefore, it is necessary to find a suitable thickener to solve this problem. Commercially available thickeners suitable for the present invention are preferably the polyether modified associative type Reholate 299 of Haimines and the associative type ViscoPlus 3060 of Digao, and the mass ratio of the two in the system is preferably 1 (1-2). The viscosity of the component B can be increased by Reholate 299, but the viscosity increasing effect is not obvious after the component A and the component B are mixed, and when the mass fraction of the Reholate 299 exceeds 1.5 percent of the component B, a paint film is whitened; the ViscoPlus 3060 has the effect opposite to that of Reholate 299, so that the viscosity of the curing agent can be ensured by compounding the ViscoPlus 3060 and the Reholate 299, the viscosity of the mixture of the A and the B can also be ensured, and the sagging phenomenon is avoided.

The cosolvent in the curing agent comprises DPNB (dipropylene glycol n-butyl ether) and PM (propylene glycol methyl ether), the epoxy modified aliphatic addition amine has certain hydrophobic property, the solubility of the epoxy modified aliphatic addition amine can be improved by adding the PM, the PM is easy to disperse in deionized water, the boiling point of the DPNB is high, the openness of a paint film in a drying process can be improved, otherwise, the paint film is dried too fast in the drying process, so that water cannot volatilize, bubbles are generated, and the appearance, the tolerance and the like of the paint film are influenced. The invention is based on the selection that DPNB and PM are mixed, and the mass ratio of the DPNB to the PM is preferably (1-2): 1.

the invention also provides a preparation method of the two-component water-based epoxy silver paint, which is characterized by comprising the following steps:

(1) sequentially adding the aqueous epoxy resin dispersoid, the liquid epoxy resin and the anti-sagging resin under stirring in proportion, and uniformly dispersing to obtain a mixed solution a; preparing a lithium magnesium sodium silicate solution according to a proportion; preparing passivated aluminum paste according to a proportion; adding a lithium magnesium sodium silicate solution and passivated aluminum paste into the mixed solution a, and uniformly dispersing; and sequentially adding the auxiliary agent and the deionized water, uniformly dispersing, and obtaining the main agent after the detection is qualified.

(2) Adding the aliphatic amine addition product according to a certain proportion, stirring, dispersing the cosolvent, the auxiliary agent and the deionized water into the aliphatic amine addition product, and uniformly stirring to obtain the curing agent.

(3) And mixing the main agent and the curing agent in proportion, and uniformly stirring to obtain the double-component water-based epoxy silver paint.

As a preferred embodiment of the two-component water-based epoxy silver paint, the two-component water-based epoxy silver paint is applied to substrate coating.

Substrates that can be coated in the present invention include, but are not limited to, metal substrates and carbon fiber substrates, for example, workpieces that can be formed from metal substrates and carbon fiber substrates, preferably shock absorbers, engines, carbon fiber bicycle frames, fishing rods, and the like.

Compared with the prior art, the invention has the beneficial effects that: the invention improves the stability and the weather resistance of the oily aluminum paste on the premise of ensuring the glossiness and the flicker degree of the oily aluminum paste; the water-based system has low VOC content, no pungent smell and low price, can greatly reduce the price of the water-based two-component epoxy aluminum powder paint and expand the application range of the water-based two-component epoxy aluminum powder paint; the viscosity of the curing agent is moderate after treatment, the curing agent is stirred at high speed without bubbles and can be packaged immediately; the main agent and the curing agent have good mixing compatibility, better construction performance, easy manual stirring and long activation period; the paint system has good sagging resistance, high gloss, and good weather resistance and salt spray resistance.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.

The preparation method of the two-component water-based epoxy silver paint comprises the following steps:

(1) sequentially adding the aqueous epoxy resin dispersoid, the liquid epoxy resin and the anti-sagging resin under stirring in proportion, and uniformly dispersing to obtain a mixed solution a; preparing a lithium magnesium sodium silicate solution according to a proportion; preparing passivated aluminum paste according to a proportion; adding a lithium magnesium sodium silicate solution and passivated aluminum paste into the mixed solution a, and uniformly dispersing; and sequentially adding the auxiliary agent and the deionized water, uniformly dispersing, and obtaining the main agent after the detection is qualified.

(2) Adding the fatty amine addition product according to a certain proportion, stirring, dispersing the cosolvent, the auxiliary agent and the deionized water into the fatty amine addition product, uniformly stirring, and obtaining the curing agent after the inspection is qualified.

(3) And mixing the main agent and the curing agent in proportion, and uniformly stirring to obtain the two-component water-based epoxy silver paint.

Example 1

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 50% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 5% liquid epoxy resin Beckopox EP 147w, 5% sag resistant resin SETAQUA 6803, 20% lithium magnesium sodium silicate solution, 15% passivated aluminum paste, 2% wetting agent BYK-348, 1.5% silane coupling agent A-187, 1.5% flash rust inhibitor aid ASCONIUM-142 DA; the curing agent comprises the following components in percentage by weight: 40% aliphatic amine adduct curing agent Epikure 8545-W-52, 2.5% co-solvent DPNB and 2.5% co-solvent PM, 1% defoamer Airex902W, 1% thickener Reholate 299 and 1% thickener ViscoPlus 3060, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 4: 1.

example 2

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 40% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 8% liquid epoxy resin Beckopox EP 147w, 6% sag resistant resin SETAQUA 6803, 20% lithium magnesium sodium silicate solution, 20% passivated aluminum paste, 3% wetting agent BYK-348, 1.5% silane coupling agent A-187, 1.5% flash rust inhibitor aid ASCONIUM-142 DA; the curing agent comprises the following components in percentage by weight: 40% aliphatic amine adduct curing agent Epikure 8545-W-52, 2.5% co-solvent DPNB and 2.5% co-solvent PM, 1% defoamer Airex902W, 1% thickener Reholate 299 and 1% thickener ViscoPlus 3060, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 3: 1.

Example 3

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 70% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 4% liquid epoxy resin Beckopox EP 147w, 2% sag resistant resin SETAQUA 6803, 10% lithium magnesium sodium silicate solution, 13.5% passivated aluminum paste, 2% wetting agent BYK-348, 1% silane coupling agent A-187, 1% flash rust inhibitor aid ASCONIUM-142 DA; the curing agent comprises the following components in percentage by weight: 60% aliphatic amine adduct curing agent Epikure 8545-W-52, 2% cosolvent DPNB and 1% cosolvent PM, 0.3% defoamer Airex902W, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 5: 1.

Example 4

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 45% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 5% liquid epoxy resin Beckopox EP 147w, 5% sag resistant resin SETAQUA 6803, 20% lithium magnesium sodium silicate solution, 20% passivated aluminum paste, 2% wetting agent BYK-348, 1.5% silane coupling agent A-187, 1.5% flash rust inhibitor aid ASCONIUM-142 DA; the component B comprises the following components in percentage by weight: 50% aliphatic amine adduct curing agent Epikure 8545-W-52, 2% co-solvent DPNB and 2% co-solvent PM, 1% defoamer Airex902W, 0.5% thickener Reholate 299 and 0.5% thickener ViscoPlus 3060, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 4: 1.

Example 5

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 65% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 5% liquid epoxy resin Beckopox EP 147w, 3% sag resistant resin SETAQUA 6803, 10% lithium magnesium sodium silicate solution, 15% passivated aluminum paste, 1% wetting agent BYK-348, 0.5% silane coupling agent A-187, 0.5% flash rust inhibitor aid ASCONIUM-142 DA; the curing agent comprises the following components in percentage by weight: 50% aliphatic amine adduct curing agent Epikure 8545-W-52, 2% co-solvent DPNB and 2% co-solvent PM, 1% defoamer Airex902W, 0.5% thickener Reholate 299 and 0.5% thickener ViscoPlus 3060, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 4: 1.

Example 6

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 50% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 6% liquid epoxy resin Beckopox EP 147w, 3.5% sag resistant resin SETAQUA 6803, 20% lithium magnesium sodium silicate solution, 20% passivated aluminum paste, 0.5% flash rust inhibitor ASCONIUM-142 DA; the curing agent comprises the following components in percentage by weight: 50% aliphatic amine adduct curing agent Epikure 8545-W-52, 2% co-solvent DPNB and 2% co-solvent PM, 1% defoamer Airex902W, 0.5% thickener Reholate 299 and 0.5% thickener ViscoPlus 3060, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 4: 1.

Comparative example 1

The two-component water-based epoxy silver paint provided by the embodiment of the invention comprises a main agent and a curing agent, wherein the main agent comprises the following components in percentage by weight: 80% aqueous epoxy resin dispersion EPIKOTE 3523-WH-53, 2% liquid epoxy resin Beckopox EP 147w, 1% sag resistant resin SETAQUA 6803, 5% lithium magnesium sodium silicate solution, 5% passivated aluminum paste, 4% wetting agent BYK-348, 1.5% silane coupling agent A-187, 1.5% flash rust inhibitor aid ASCONIUM-142 DA; the curing agent comprises the following components in percentage by weight: 70% aliphatic amine adduct curing agent Epikure 8545-W-52, 3.5% co-solvent DPNB and 3.5% co-solvent PM, 0.5% defoamer Airex902W, 1.5% thickener Reholate 299 and 3% thickener ViscoPlus 3060, the balance being deionized water.

Wherein the weight ratio of the main agent to the curing agent is 4: 1.

comparative example 2

In order to compare the effect of hydrophilic solvents in passivated aluminium paste on its stability, the invention was specifically introduced in comparative example 2. The hydrophilic solvent in the passivated aluminum paste of comparative example 2 was n-butanol, and the remaining conditions were the same as in example 1.

Comparative example 3

In order to verify the actual effect of the waterborne epoxy silver paint, the invention particularly introduces the commercial waterborne epoxy silver paint and a matched curing agent thereof. The construction conditions were the same as in all examples.

Examples of effects

The two-component water-based epoxy silver paint disclosed in the embodiments 1-6 and the comparative examples 1-3 is respectively prepared according to the construction proportion, deionized water is added to adjust the spraying viscosity to be proper, then the paint is coated and covered on a zinc series phosphated steel plate, the spraying film thickness is 35-45 mu m, after flash drying is carried out for 15-20 min, and then baking is carried out for 1-2 h at the temperature of 60-80 ℃. Then, the mixture was left at room temperature for 7 days, and the gloss, water resistance, weather resistance and the like were measured. After drying, the paint films were tested for their properties, the results of which are given in Table 1.

The performance test method comprises the following steps:

(1) gloss testing: the gloss meter measures according to GB/T9754-2007 standard by adopting a BYK AG-4446 model, measures for 6 times at different parts of a paint film, and then calculates an average value.

(2) And (3) determining the activation period: the two-component coating is mixed according to a specified ratio, the temperature of each component of the product is preset to (23 +/-2) DEG C, then after the two components are uniformly mixed according to the ratio, 250mL of the mixture is filled into a plastic tank, a glass bottle or an iron tank with the capacity of about 300mL and the inner diameter of (75 +/-5) mm, a cover is covered, the content is checked after the mixture is placed for a specified time, if no precipitate exists or the mixture is easily dispersed uniformly after stirring, the viscosity is not obviously increased compared with the viscosity immediately after the mixture, the gelation phenomenon does not occur, and the grazing test result is not reduced, the product is judged to be 'pass'.

(3) Sag resistance: in the case of wet-on-wet spraying (interval time of not more than 0.5 hours), the wet film thickness of the paint film reaches the prescribed specification without causing sagging.

(4) Heat-resistant salt spray: the salt spray resistance was measured according to GB/T1771. Selecting a carbon steel substrate, and scratching the substrate metal. And (3) taking out the test plate after testing according to a specified period, observing by eye, inserting a blade along the surface of the substrate after adjusting the state for 16h, prying the coating, and judging the change of the adhesive force according to the stripping condition of the coating. In testing multi-coated test panels, the location of the damaged coating or interface should be noted.

(5) Weather resistance: the accelerated weathering test was carried out as specified in "Exposure cycle type 7" in appendix C of GB/T14522-2008. And evaluating the comprehensive aging performance grade of the coating according to the decorative property in GB/T1766.

(6) Water resistance: the water resistance test was carried out according to the specification of GB/T5209. Soaking with deionized water (conductivity less than or equal to 2 μ s/cm), maintaining three-quarters of the sample plate in water, adjusting water temperature to 40 + -1 deg.C, and maintaining the temperature in the whole process.

TABLE 1

As can be seen from Table 1, the two-component water-based epoxy silver paint of the invention has good adhesion, high gloss, long activation period, good anti-sagging property, better acid, alkali, weather and salt fog resistance than the commercially available water-based epoxy silver paint (comparative example 3), good storage stability, no change after 30 days of storage at 48 ℃, and no fineness thickening phenomenon.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.