Waterborne epoxy emulsion as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of coatings, and particularly relates to a waterborne epoxy emulsion as well as a preparation method and application thereof.The waterborne epoxy emulsion is prepared from an epoxy emulsifier, basic epoxy resin, a cosolvent and water, the epoxy emulsifier contains an emulsifier in which bisphenol A or a phenolic aldehyde chain segment and a polyether chain segment are introduced to a primary amine position in long-chain amino-terminated polyether amine, and the basic epoxy resin contains the bisphenol A chain segment. According to the invention, the compatibility of epoxy resin and water is improved, the possibility of phase separation is reduced, the overall performance of the emulsion is further improved, the problem that the existing waterborne epoxy emulsion is extremely easy to have insufficient stability due to phase separation or precipitation is solved, the long-term use effect and storage life of the emulsion are ensured, and the application prospect is wide. Meanwhile, the quick drying of the coating is facilitated, the construction efficiency is improved, and the use of organic solvents can be greatly reduced, so that the pollution to the environment is reduced, the safety in the construction process is improved, and the requirement of sustainable development is met.

Description

Technical Solution

[0001] The invention belongs to the technical field of coatings, and specifically relates to a water-based epoxy emulsion and a preparation method and application thereof. Background Art

[0002] Paint is a material widely used on the surface of objects. It can form a continuous film on the surface of objects to play a role in protection, decoration or other special functions (such as insulation, rust prevention, mildew prevention, heat resistance, etc.). Epoxy resin is widely used in various fields as a raw material for paint due to its good mechanical properties, excellent bonding properties and strong chemical stability. Traditional epoxy resin systems are not easy to flow, so a large amount of organic solvents are often needed to improve their processing performance. The added organic solvents are volatile, which not only pollutes the environment, but also harms human health. In order to ensure the health of the environment and human body, water-based epoxy resins came into being. Water-based epoxy resins use water as a dispersion medium, which greatly reduces the emission of volatile organic compounds (VOCs) and meets environmental protection requirements. In addition, because water-based epoxy resins have good fluidity, they are easy to construct and clean. However, most of the methods currently used on the market use an external emulsifier to emulsify and disperse the basic epoxy resin to obtain a water-based epoxy emulsion. A water-based epoxy emulsion refers to an emulsion formed by epoxy resin dispersed in water in the form of particles or droplets. The emulsion obtained by this method has shortcomings in terms of storage stability and mechanical properties.

[0003] There are studies on the problems of the method of adding an emulsifier in the prior art, such as patent application CN113831508A-a water-based epoxy curing agent and its preparation method and water-based epoxy coating, which prepares the water-based epoxy curing agent by modifying the amine solution of phenolic epoxy resin and introducing polyether segments and bisphenol A segments. Another example is patent application CN102432830A-a water-based epoxy resin curing agent emulsion and its preparation method, which prepares the water-based epoxy resin curing agent emulsion by reacting water-based phenolic epoxy resin and modified organic polyamine. The above-mentioned prior art prepares a reactive emulsifier, which is combined with the epoxy resin through a chemical bond to improve the stability of the emulsion. At the same time, the performance of the coating can be further improved by reasonably designing the structure of the emulsifier. Although the existing water-based epoxy emulsion and its preparation method have made certain progress, due to its relatively complicated preparation process, the stability, curing speed and coating quality of the water-based epoxy emulsion are all poor, and it is difficult to obtain a simple and efficient method for preparing a water-based epoxy emulsion. Therefore, a new technical solution is needed to solve the above technical problems. Summary of the invention

[0004] The object of the present invention is to provide a water-based epoxy emulsion and a preparation method and application thereof, so as to solve the problems raised in the above background technology that the current water-based epoxy emulsion and its preparation method have a relatively complicated preparation process, resulting in poor stability, curing speed and coating quality of the water-based epoxy emulsion, and it is difficult to obtain a simple and efficient preparation method of the water-based epoxy emulsion.

[0005] To achieve the above object, the present invention provides the following technical solution: an aqueous epoxy emulsion, which is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water; the aqueous epoxy emulsion comprises, according to the weight proportions of the raw material components, 5 to 8 parts of epoxy emulsifier, 50 to 55 parts of basic epoxy resin, 8 to 15 parts of cosolvent and 35 to 40 parts of water, wherein the epoxy emulsifier contains an emulsifier in which bisphenol A or phenolic segments and polyether segments are introduced into the primary amine position of the long-chain terminal amino polyether amine, and the basic epoxy resin contains a bisphenol A segment.

[0006] Furthermore, the epoxy emulsifier comprises, by weight, 50 to 70 parts of polyetheramine, 20 to 35 parts of epoxy resin and 10 to 15 parts of epoxy reactive diluent, wherein the polyetheramine is one of Huntsman polyetheramine M2070 and Huntsman polyetheramine M3085; the epoxy resin is one or more of E-44 epoxy resin, E-20 epoxy resin, E-51 epoxy resin and phenolic epoxy resin NPPN-638S; and the epoxy diluent is one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and polybutylene glycol diglycidyl ether.

[0007] Furthermore, the base epoxy resin is one of E-44 epoxy resin, E-20 epoxy resin and E-51 epoxy resin.

[0008] Furthermore, the co-solvent is one of propylene glycol methyl ether and ethylene glycol butyl ether.

[0009] According to the above-mentioned raw material components and their formula amounts, a water-based epoxy emulsion is prepared, and the specific preparation steps are as follows: S1. Preparation of epoxy emulsifier: First, epoxy resin and epoxy diluent are mixed to prepare a dissolving solution; then, the dissolving solution is added to the polyetheramine by stirring while adding, and the temperature is controlled within 80-120° C., and after the addition is completed, the temperature is kept for 3-4 hours, and finally, the temperature is cooled to room temperature to obtain the epoxy emulsifier for standby use; S2, preparing water-based epoxy emulsion: first, stir the formulated amount of basic epoxy resin and the formulated amount of co-solvent evenly; secondly, after heating to 60-80°C, add the epoxy emulsifier prepared in S1, and control the shear rate within 400-500 r / min; then, add the formulated amount of water, and control the temperature within 60-80°C during the addition. After the addition is completed, increase the shear rate to 1000-4000 r / min, and keep warm for 2-4 hours; finally, cool to room temperature to obtain a water-based epoxy emulsion.

[0010] In addition to the above technical solutions, the waterborne epoxy emulsion prepared above can also be mixed with a waterborne epoxy curing agent to prepare a waterborne epoxy coating.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts an emulsifier containing bisphenol A or phenolic chain segments and polyether chain segments introduced into the primary amine position of the long-chain terminal amino polyether amine in the epoxy emulsifier, which not only makes the epoxy emulsifier have the structural characteristics of epoxy resin or phenolic epoxy resin, thereby giving the epoxy emulsifier good compatibility with the basic epoxy resin and improving the stability of the water-based epoxy emulsion, but also makes the epoxy emulsifier more effectively disperse and stabilize epoxy resin particles, which helps to improve the compatibility of epoxy resin and water, reduce the possibility of phase separation, and thus improve the overall performance of the water-based epoxy emulsion, solves the problem that the existing water-based epoxy emulsion is very easy to have insufficient stability due to phase separation or precipitation, and ensures the long-term use effect and storage of the water-based epoxy emulsion The design of containing bisphenol A chain segments in the basic epoxy resin helps to form a stronger cross-linked network, thereby improving the mechanical properties of the coating, such as hardness, wear resistance and impact resistance. Especially when used on substrates such as concrete, it can more effectively fill pores and cracks, strengthen internal adhesion, and form a dense network structure. At the same time, the introduction of bisphenol A chain segments can also improve the chemical resistance of the coating, so that it can maintain stable performance in harsh chemical environments. The addition of co-solvents and water helps the coating to dry quickly, improve construction efficiency, and greatly reduce the use of organic solvents, thereby reducing pollution to the environment, improving safety during construction, and meeting the requirements of sustainable development. 2. The present invention accurately proportions polyetheramine, epoxy resin and epoxy reactive diluent, so that the epoxy emulsifier has higher emulsification efficiency and better stability, so that the basic epoxy resin can be more effectively dispersed in water to form a stable and uniform emulsion. The epoxy resin and the epoxy diluent are first mixed to form a solution, and then the solution is added to the polyetheramine to prepare an epoxy emulsifier having the structural characteristics of epoxy resin or phenolic epoxy resin. The quality and performance of the epoxy emulsifier are ensured by accurately controlling the reaction temperature and the insulation time, which not only makes the preparation of the epoxy emulsifier simpler and easier, but also easy to control, which is conducive to industrial production. By adding the optimized epoxy emulsifier to the water-based epoxy emulsion, the stability of the water-based epoxy emulsion is significantly improved, and it is not easy to stratify and precipitate during storage, and can maintain a uniform dispersion state for a long time. 3. The present invention ensures the stability, curing speed and coating quality of the water-based epoxy emulsion by accurately designing the raw material components and controlling the temperature, shear rate and holding time during the preparation process, so that the overall performance of the water-based epoxy emulsion is effectively improved. Compared with the complicated preparation process in the prior art, the present invention realizes the simple and efficient preparation of the water-based epoxy emulsion, which helps to reduce the uncertainty and error in the preparation process and improve the quality and consistency of the product. By accurately controlling the two shear rates, it not only helps to avoid the destruction of the emulsion caused by excessive shearing, but also ensures the uniform dispersion of the epoxy resin particles in water, achieving a better emulsification effect. By simplifying the preparation process, unnecessary steps and energy consumption are reduced, the energy utilization efficiency is improved, which is conducive to the realization of industrial production and ensures the production efficiency of the water-based epoxy emulsion. 4. The present invention prepares a water-based epoxy coating with excellent performance by mixing the prepared water-based epoxy emulsion with a water-based epoxy curing agent. The coating has excellent mechanical properties, chemical resistance, weather resistance and adhesion, etc., and can meet the use requirements in various complex environments. Compared with the existing solvent-based epoxy coating, the water-based epoxy coating has lower volatile organic compound (VOC) emissions, is more in line with environmental protection requirements, helps to reduce air pollution, protect the environment and human health, and also has better construction performance, such as easy to brush, fast drying, good leveling, etc., which helps to improve construction efficiency, reduce construction costs, effectively improve the quality of the final coating film, and also help to broaden the market application scope of water-based epoxy coatings and improve the market competitiveness of the coating. DETAILED DESCRIPTION

[0012] The following examples are used to further illustrate the content of the present invention, but do not limit the application of the present invention. Instead, they clearly and completely describe the technical solutions in the embodiments of the present invention. Embodiment 1:

[0013] The present embodiment provides a water-based epoxy emulsion, which is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water, wherein the epoxy emulsifier contains an emulsifier that introduces bisphenol A or phenolic segments and polyether segments at the primary amine position in the long-chain terminal amino polyether amine, wherein the polyether segment refers to a segment formed by the reaction of an epoxy diluent with a primary amine, and the basic epoxy resin contains a bisphenol A segment; The specific preparation process is as follows: First, prepare the epoxy emulsifier: pour 60 parts of polyetheramine into a three-necked flask by weight, then mix and stir 25 parts of epoxy resin E51 and 15 parts of polypropylene glycol diglycidyl ether to dissolve the epoxy resin E51 in the polypropylene glycol diglycidyl ether to obtain a solution; then slowly drop the solution mixed with 25 parts of epoxy resin E51 and 15 parts of polypropylene glycol diglycidyl ether into the three-necked flask containing 60 parts of polyetheramine, control the temperature of the solution in the three-necked flask at 80° C. after the dropwise addition, continue to keep warm for 3 hours after the dropwise addition is completed, and obtain the epoxy emulsifier after cooling to room temperature; Prepare waterborne epoxy emulsion: add 55 parts of E-44 epoxy resin to a three-necked flask by weight, weigh 10 parts of propylene glycol methyl ether and stir evenly, and control the shear rate within 400-500 r / min; then slowly drop 5 parts of epoxy emulsifier prepared above into the three-necked flask, control the temperature of the solution in the three-necked flask at 60°C during the dropwise addition, and after the dropwise addition is completed, the shear rate is increased to 2000-2500 r / min, and the reaction is continued at 60°C for 2h, and 35 parts of deionized water are added to adjust the solid content to 50%, and the shear rate is slowly reduced to 400-500 r / min, and the waterborne epoxy emulsion is obtained by cooling to room temperature. The waterborne epoxy emulsion obtained above is milky white, has a solid content of 60%, an epoxy equivalent of 980g / mol, an average particle size of 550um, and can be stored for 6 months without stratification.

[0014] The waterborne epoxy emulsion prepared as above and the waterborne epoxy curing agent (the waterborne epoxy curing agent can be purchased or homemade, and its active hydrogen equivalent is 415 g / mol) are mixed in a mass ratio of 10:1 to prepare a waterborne epoxy coating, so that the epoxy resin curing agent in the coating reacts chemically with the epoxy resin in the waterborne epoxy emulsion to form a network of three-dimensional polymers, which encapsulate the composite material aggregate in the network, turn the linear resin into a tough solid, and thus form a coating film. The test results are shown in the following table. Embodiment 2:

[0015] In this embodiment, the water-based epoxy emulsion is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water, wherein the epoxy emulsifier contains an emulsifier that introduces bisphenol A or phenolic segments and polyether segments at the primary amine position in the long-chain terminal amino polyether amine, wherein the polyether segment refers to a segment formed by the reaction of an epoxy diluent with a primary amine, and the basic epoxy resin contains a bisphenol A segment; The specific preparation process is as follows: First, prepare the epoxy emulsifier: pour 65 parts of polyetheramine into a three-necked flask by weight, then mix and stir 25 parts of epoxy resin E44 and 10 parts of polyethylene glycol diglycidyl ether to dissolve the epoxy resin E44 in the polyethylene glycol diglycidyl ether to obtain a solution; then slowly drop the solution mixed with 25 parts of epoxy resin E44 and 10 parts of polyethylene glycol diglycidyl ether into the three-necked flask containing 65 parts of polyetheramine, control the temperature of the solution in the three-necked flask at 80° C., continue to keep warm for 3 hours after the dropwise addition is completed, and obtain the epoxy emulsifier after cooling to room temperature; Prepare waterborne epoxy emulsion: add 52 parts of E-51 epoxy resin to a three-necked flask by weight, weigh 10 parts of propylene glycol methyl ether and stir evenly, and control the shear rate within 400-500 r / min; then slowly drop 8 parts of epoxy emulsifier prepared above into the three-necked flask, control the temperature of the solution in the three-necked flask at 60°C during the dropwise addition, and after the dropwise addition is completed, the shear rate is increased to 2000-2500 r / min, and the reaction is continued at 60°C for 2h, and 40 parts of deionized water are added to adjust the solid content to 60%, and the shear rate is slowly reduced to 400-500 r / min, and the waterborne epoxy emulsion is obtained by cooling to room temperature. The waterborne epoxy emulsion obtained above is milky white, has a solid content of 60%, an epoxy equivalent of 1020g / mol, an average particle size of 500um, and can be stored for 6 months without stratification.

[0016] The waterborne epoxy emulsion prepared as above and the waterborne epoxy curing agent (the waterborne epoxy curing agent can be purchased or homemade, and its active hydrogen equivalent is 415 g / mol) are mixed in a mass ratio of 10:1 to prepare a waterborne epoxy coating, so that the epoxy resin curing agent in the coating reacts chemically with the epoxy resin in the waterborne epoxy emulsion to form a network of three-dimensional polymers, which encapsulate the composite material aggregate in the network and turn the linear resin into a tough solid, thereby forming a coating film. The test results are shown in the following table. Embodiment 3:

[0017] In this embodiment, the water-based epoxy emulsion is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water, wherein the epoxy emulsifier contains an emulsifier that introduces bisphenol A or phenolic segments and polyether segments at the primary amine position in the long-chain terminal amino polyether amine, wherein the polyether segment refers to a segment formed by the reaction of an epoxy diluent with a primary amine, and the basic epoxy resin contains a bisphenol A segment; The specific preparation process is as follows: First, prepare the epoxy emulsifier: pour 65 parts of polyetheramine into a three-necked flask by weight, then mix and stir 20 parts of epoxy resin E44, 5 parts of phenolic epoxy resin NPPN-638S and 10 parts of polyethylene glycol diglycidyl ether, so that the epoxy resin E44 and the phenolic epoxy resin NPPN-638S can be dissolved in the polyethylene glycol diglycidyl ether to obtain a dissolved solution; then slowly drop the dissolved solution mixed with 20 parts of epoxy resin E44, 5 parts of phenolic epoxy resin NPPN-638S and 10 parts of polyethylene glycol diglycidyl ether into the three-necked flask containing 65 parts of polyetheramine, control the temperature of the solution in the three-necked flask at 80° C. after the dropwise addition is completed, continue to keep warm for 3 hours, and cool to room temperature to obtain the epoxy emulsifier; Prepare waterborne epoxy emulsion: add 55 parts of E-20 epoxy resin to a three-necked flask by weight, weigh 15 parts of propylene glycol methyl ether and stir evenly, and control the shear rate within 400-500 r / min; then slowly drop 5 parts of epoxy emulsifier prepared above into the three-necked flask, control the temperature of the solution in the three-necked flask at 60°C during the dropwise addition, and after the dropwise addition is completed, the shear rate is increased to 2000-2500 r / min, and the reaction is continued at 60°C for 2h, and 38 parts of deionized water are added to adjust the solid content to 60%, and the shear rate is slowly reduced to 400-500 r / min, and the waterborne epoxy emulsion is obtained by cooling to room temperature. The waterborne epoxy emulsion obtained above is milky white, has a solid content of 60%, an epoxy equivalent of 910g / mol, an average particle size of 520um, and can be stored for 6 months without stratification.

[0018] The waterborne epoxy emulsion prepared as above and the waterborne epoxy curing agent (the waterborne epoxy curing agent can be purchased or homemade, and its active hydrogen equivalent is 415 g / mol) are mixed in a mass ratio of 10:1 to prepare a waterborne epoxy coating, so that the epoxy resin curing agent in the coating reacts chemically with the epoxy resin in the waterborne epoxy emulsion to form a network of three-dimensional polymers, which encapsulate the composite material aggregate in the network and turn the linear resin into a tough solid, thereby forming a coating film. The test results are shown in the following table. Embodiment 4:

[0019] In this embodiment, the water-based epoxy emulsion is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water, wherein the epoxy emulsifier contains an emulsifier that introduces bisphenol A or phenolic segments and polyether segments at the primary amine position in the long-chain terminal amino polyether amine, wherein the polyether segment refers to a segment formed by the reaction of an epoxy diluent with a primary amine, and the basic epoxy resin contains a bisphenol A segment; The specific preparation process is as follows: First, prepare the epoxy emulsifier: pour 65 parts of polyetheramine into a three-necked flask by weight, then mix and stir 15 parts of epoxy resin E51, 10 parts of phenolic epoxy resin NPPN-638S and 10 parts of polytetramethylene glycol diglycidyl ether, so that the epoxy resin E51 and the phenolic epoxy resin NPPN-638S can be dissolved in the polytetramethylene glycol diglycidyl ether to obtain a dissolved solution; then slowly drop the dissolved solution mixed with 15 parts of epoxy resin E51, 10 parts of phenolic epoxy resin NPPN-638S and 10 parts of polytetramethylene glycol diglycidyl ether into the three-necked flask containing 65 parts of polyetheramine, control the temperature of the solution in the three-necked flask at 80° C. after the dropwise addition is completed, continue to keep warm for 3 hours, and cool to room temperature to obtain the epoxy emulsifier; Prepare waterborne epoxy emulsion: add 55 parts of E-44 epoxy resin to a three-necked flask by weight, weigh 15 parts of propylene glycol methyl ether and stir evenly, and control the shear rate within 400-500 r / min; then slowly drop 5 parts of epoxy emulsifier prepared above into the three-necked flask, control the temperature of the solution in the three-necked flask at 60°C during the dropwise addition, and after the dropwise addition is completed, the shear rate is increased to 2000-2500 r / min, and the reaction is continued at 60°C for 2h, and 38 parts of deionized water are added to adjust the solid content to 60%, and the shear rate is slowly reduced to 400-500 r / min, and the waterborne epoxy emulsion is obtained by cooling to room temperature. The waterborne epoxy emulsion obtained above is milky white, has a solid content of 60%, an epoxy equivalent of 920g / mol, an average particle size of 480um, and can be stored for 6 months without stratification.

[0020] The waterborne epoxy emulsion prepared as above and the waterborne epoxy curing agent (the waterborne epoxy curing agent can be purchased or homemade, and its active hydrogen equivalent is 415 g / mol) are mixed in a mass ratio of 10:1 to prepare a waterborne epoxy coating, so that the epoxy resin curing agent in the coating reacts chemically with the epoxy resin in the waterborne epoxy emulsion to form a network of three-dimensional polymers, which encapsulate the composite material aggregate in the network and turn the linear resin into a tough solid, thereby forming a coating film. The test results are shown in the following table. Embodiment 5:

[0021] In this embodiment, the water-based epoxy emulsion is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water, wherein the epoxy emulsifier contains an emulsifier that introduces bisphenol A or phenolic segments and polyether segments at the primary amine position in the long-chain terminal amino polyether amine, wherein the polyether segment refers to a segment formed by the reaction of an epoxy diluent with a primary amine, and the basic epoxy resin contains a bisphenol A segment; The specific preparation process is as follows: First, prepare the epoxy emulsifier: pour 65 parts of polyetheramine into a three-necked flask by weight, then mix and stir 20 parts of epoxy resin E44, 5 parts of phenolic epoxy resin NPPN-638S and 10 parts of polyethylene glycol diglycidyl ether, so that the epoxy resin E44 and the phenolic epoxy resin NPPN-638S can be dissolved in the polyethylene glycol diglycidyl ether to obtain a dissolved solution; then slowly drop the dissolved solution mixed with 20 parts of epoxy resin E44, 5 parts of phenolic epoxy resin NPPN-638S and 10 parts of polyethylene glycol diglycidyl ether into the three-necked flask containing 65 parts of polyetheramine, control the temperature of the solution in the three-necked flask at 80° C. after the dropwise addition is completed, continue to keep warm for 3 hours, and cool to room temperature to obtain the epoxy emulsifier; Prepare waterborne epoxy emulsion: add 60 parts of E-51 epoxy resin to a three-necked flask by weight, weigh 15 parts of propylene glycol methyl ether and stir evenly, and control the shear rate within 400-500 r / min; then slowly drop 10 parts of epoxy emulsifier prepared above into the three-necked flask, control the temperature of the solution in the three-necked flask at 60°C during the dropwise addition, and after the dropwise addition is completed, the shear rate is increased to 2000-2500 r / min, and the reaction is continued at 60°C for 2h, and 25 parts of deionized water are added to adjust the solid content to 60%, and the shear rate is slowly reduced to 400-500 r / min, and the waterborne epoxy emulsion is obtained by cooling to room temperature. The waterborne epoxy emulsion obtained above is milky white, has a solid content of 60%, an epoxy equivalent of 880g / mol, an average particle size of 490um, and can be stored for 6 months without stratification.

[0022] The waterborne epoxy emulsion prepared as above and the waterborne epoxy curing agent (the waterborne epoxy curing agent can be purchased or homemade, and its active hydrogen equivalent is 415 g / mol) are mixed in a mass ratio of 10:1 to prepare a waterborne epoxy coating, so that the epoxy resin curing agent in the coating reacts chemically with the epoxy resin in the waterborne epoxy emulsion to form a network of three-dimensional polymers, which encapsulate the composite material aggregate in the network and turn the linear resin into a tough solid, thereby forming a coating film. The test results are shown in the following table.

[0023] Comparative Example 1: The waterborne epoxy coating prepared in this comparative example is prepared by mixing a commercially available waterborne epoxy emulsion and a commercially available waterborne epoxy curing agent, and the test results thereof are also shown in the following table.

[0024] The following is a test of the two-component waterborne epoxy varnish prepared in Examples 1-5 and Comparative Example 1 and the corresponding paint film properties, and the test method is as follows: The same component A was used as a waterborne epoxy curing agent and different component B waterborne epoxy emulsions were used as waterborne epoxy resins, wherein component A was Banco920 (a product produced by Lianku Chemical) diluted with propylene glycol methyl ether and water in equal mass, and mixed at a molar ratio of active hydrogen to epoxy group of 1:1.25 to obtain a two-component waterborne epoxy varnish (i.e., waterborne epoxy coating). The two-component waterborne epoxy varnish was then formed into a coating film, and its performance was tested. The test is carried out according to the following standard method: Surface drying time: According to the requirements of the national standard GB / T1728-1979, the surface drying time of various paint films is tested by finger touch method; Hardness: Tested in accordance with the national standard GB / T6739-2006 "Determination of paint film hardness by pencil method for paints and varnishes"; Adhesion: According to the requirements of national standard GB / T9286-1998, the adhesion of different paint films is rated by manual gridding method; Water resistance: tested in accordance with the national standard GB / T1733-99; Testing environment conditions: temperature 25±2 ℃; humidity (50±5%) RH; The test results are shown in the following table: ; It can be seen from the above table that the epoxy emulsifier obtained by modifying the amino-terminated polyether amine with epoxy resin and epoxy diluent, and then preparing the epoxy emulsion, can significantly improve the curing rate of the water-based epoxy coating formed by it, and the mechanical properties and water resistance of the corresponding paint film. Therefore, the coating film obtained by the water-based epoxy coating formed by the water-based epoxy emulsion prepared by the present invention has excellent mechanical properties, water resistance and corrosion resistance.

Claims

1. A water-based epoxy emulsion, characterized in that: The water-based epoxy emulsion is prepared from an epoxy emulsifier, a basic epoxy resin, a cosolvent and water; the water-based epoxy emulsion comprises, according to the weight proportions of the raw material components, 5 to 8 parts of epoxy emulsifier, 50 to 55 parts of basic epoxy resin, 8 to 15 parts of cosolvent and 35 to 40 parts of water, wherein the epoxy emulsifier contains an emulsifier in which bisphenol A or phenolic segments and polyether segments are introduced into the primary amine position of the long-chain terminal amino polyether amine, and the basic epoxy resin contains a bisphenol A segment.

2. A water-based epoxy emulsion according to claim 1, characterized in that: The epoxy emulsifier comprises, by weight, 50 to 70 parts of polyetheramine, 20 to 35 parts of epoxy resin and 10 to 15 parts of epoxy active diluent.

3. A water-based epoxy emulsion according to claim 2, characterized in that: The polyetheramine is one of Huntsman polyetheramine M2070 and Huntsman polyetheramine M3085.

4. A water-based epoxy emulsion according to claim 2, characterized in that: The epoxy resin is one or more of E-44 epoxy resin, E-20 epoxy resin, E-51 epoxy resin, and phenolic epoxy resin NPPN-638S.

5. A water-based epoxy emulsion according to claim 2, characterized in that: The epoxy diluent is one or more of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether and polybutylene glycol diglycidyl ether.

6. A water-based epoxy emulsion according to claim 2, characterized in that: The specific preparation steps of the epoxy emulsifier are: first, epoxy resin and epoxy diluent are mixed to prepare a dissolving solution; then, the dissolving solution is added to the polyetheramine by stirring while adding, and the temperature is controlled within 80-120° C., and after the addition is completed, the temperature is kept for 3-4 hours, and finally, the epoxy emulsifier is obtained after the temperature is cooled to room temperature.

7. A water-based epoxy emulsion according to claim 1, characterized in that: The base epoxy resin is one of E-44 epoxy resin, E-20 epoxy resin and E-51 epoxy resin.

8. The aqueous epoxy emulsion according to claim 1, characterized in that: The co-solvent is one of propylene glycol methyl ether and ethylene glycol butyl ether.

9. A method for preparing a waterborne epoxy emulsion according to any one of claims 1 to 8, characterized in that: The specific preparation steps are as follows: first, a formulated amount of basic epoxy resin and a formulated amount of co-solvent are uniformly stirred; second, after heating to 60-80°C, a formulated amount of epoxy emulsifier is added, and the shear rate is controlled within 400-500 r / min; then, a formulated amount of water is added, and the temperature is controlled within 60-80°C during the addition, and after the addition is completed, the shear rate is increased to 1000-4000 r / min, and the temperature is kept for 2-4 hours; finally, the water is cooled to room temperature to obtain a water-based epoxy emulsion.

10. A waterborne epoxy emulsion as claimed in any one of claims 1 to 8 mixed with a waterborne epoxy curing agent for use in preparing a waterborne epoxy coating.