CN102504282B - Preparation method of waterborne epoxy resin emulsion - Google Patents

Abstract

The invention relates to a preparation method of water-based epoxy resin emulsion, which comprises the following steps: mixing bisphenol A epoxy resin, polyethylene glycol monomethyl ether and toluene, stirring, and azeotropic dehydration to obtain a mixed liquid; dissolving the catalyst in In toluene, then mix the liquid, heat up under magnetic stirring, and react under nitrogen protection. When the retention rate of bisphenol A epoxy resin drops to 50%, evaporate the solvent under reduced pressure to obtain a reactive nonionic epoxy emulsification agent; under strong stirring of liquid epoxy resin, co-solvent, and reactive nonionic epoxy emulsifier, add distilled water dropwise to make a water-based epoxy resin emulsion. The beneficial effects of the present invention are: the epoxy resin emulsion emulsified with the non-ionic water-based epoxy resin emulsifier has good stability, is non-toxic, has zero organic volatile matter content, is safe and environmentally friendly, and maintains the excellent durability of the epoxy resin. The chemical properties also increase the flexibility of the paint film.

Description

A kind of preparation method of aqueous epoxy resin emulsion

technical field

The invention relates to the field of water-based paint, in particular to a preparation method of water-based epoxy resin emulsion.

Background technique

Epoxy resin is a thermosetting resin with good electrical insulation, chemical stability, adhesiveness, processability, etc. It is widely used in construction, machinery, electronics, aerospace and other fields. However, traditional epoxy resins can only be dissolved in organic solvents, and must be diluted with organic solvents during use. Such prepared epoxy coatings will inevitably cause harm to operators and the environment during use. In recent years, people have paid more and more attention to environmental protection. Many countries have successively promulgated laws and regulations to control volatile organic compounds (VOC), and the implementation standards have become more stringent. The development of environmentally friendly coatings with little or no organic volatile matter has become a research hotspot in the coatings industry.

Waterborne epoxy resin refers to a stable dispersion system prepared by dispersing epoxy resin in the form of particles or droplets in a dispersed phase medium with water as the continuous phase. Compared with traditional epoxy resins, water-based epoxy resins avoid environmental pollution and waste of resources caused by the use of organic solvents, can be cured at room temperature and in a humid environment, and the construction and operation properties are greatly improved. According to different preparation processes, epoxy resin can be water-based in three ways: mechanical method, phase inversion method, and self-emulsification method. The self-emulsification method is to chemically modify the epoxy resin so that it has the ability to self-disperse and emulsify in water. This method does not require additional emulsifiers, the emulsion has good stability, and the mechanical properties and appearance of the paint film are relatively good. The preparation process is complex, and the modified resin has poor chemical stability and is prone to deterioration. Both the mechanical method and the phase inversion method require the addition of an emulsifier, but the traditional emulsifier is a surfactant, which does not participate in the curing reaction of the resin. This emulsifier is easy to precipitate on the surface of the paint film after the resin is cured, which will affect the appearance of the paint film. and anti-corrosion properties. Reactive emulsifiers participate in the curing reaction of the resin and become part of the cross-linked molecular structure after curing, so they have less impact on the paint film. The development of reactive emulsifiers with good emulsifying properties is the development direction of epoxy resin emulsifiers.

The document "Shanghai Coatings" [2006, 44 (11): 19-22] synthesized an emulsifier with polyethylene glycol 4000 and epoxy resin E-44 catalyzed by potassium persulfate at 180°C in equimolar reaction, and a certain amount of The emulsifier is added to epoxy resin, distilled water is added dropwise, and the water-based emulsion can be made by vigorous stirring. However, the reaction temperature of this method is too high, the energy consumption is large, the stirring speed is high, and the equipment requirements are relatively high. Chinese patent CN1415680A utilizes epoxy resin and polyether glycol to synthesize reactive emulsifiers whose terminal groups are epoxy groups and hydroxyl groups respectively under Lewis acid catalysis, dissolves epoxy resin with co-solvent, and then adds a certain amount of this Reactive emulsifier, using a high-speed mixer, and using a phase inversion method to prepare a water-based epoxy resin emulsion. However, the reactive emulsifiers prepared by these two methods are polymeric emulsifiers with multiple surface active centers, and can only form horizontal adsorption when dispersing and emulsifying epoxy resins, but cannot form traditional micellar latex particles. The larger the diameter, the mechanical properties of the paint film will be affected.

Contents of the invention

The technical problem to be solved by the present invention is to provide a kind of preparation method of water-based epoxy resin emulsion in view of the above-mentioned prior art, and the prepared emulsifier is used for emulsifying epoxy resin, has good stability, and can be prepared and used immediately , the application is convenient, the method is simple, and the implementation is easy.

The technical solution adopted by the present invention to solve the problems of the technologies described above is: a kind of preparation method of aqueous epoxy resin emulsion, it is characterized in that comprising the following steps:

1) According to the mass percentage of each raw material: bisphenol A epoxy resin 7% ~ 24%, polyethylene glycol monomethyl ether 30% ~ 50% and toluene 30% ~ 55%, choose bisphenol A epoxy resin , polyethylene glycol monomethyl ether and toluene, spare;

Under the protection of nitrogen, mix bisphenol A epoxy resin, polyethylene glycol monomethyl ether and toluene, heat up under magnetic stirring, and azeotropically dehydrate at a temperature of 130-150°C for 2.5-3 hours to obtain a mixed liquid;

2) According to the mass percentage of each raw material: mixed liquid 90%-94.95%, toluene 5%-9.95% and catalyst 0.03%-0.06%, select the mixed liquid, toluene and catalyst obtained in step 1) and set aside;

Dissolve the catalyst in toluene, then add it to the mixed liquid obtained in step 1), raise the temperature under magnetic stirring, and strictly control the reaction at a temperature of 85-95°C under the protection of nitrogen. During the reaction, take samples regularly to analyze the epoxy value of the system. Calculate bisphenol A epoxy resin epoxy retention rate, when the retention rate of bisphenol A epoxy resin epoxy drops to 50%, decompression steams and removes solvent, obtains reactive nonionic epoxy emulsifier;

3) According to the mass percentage of each raw material: liquid epoxy resin 18%-22%, reactive non-ionic epoxy emulsifier 8%-10%, distilled water 64%-70% and co-solvent 4%-5% , select the liquid epoxy resin, the reactive nonionic epoxy emulsifier obtained in step 2), distilled water and co-solvent, and set aside;

Under strong stirring of liquid epoxy resin, co-solvent, and reactive nonionic epoxy emulsifier, distilled water is added dropwise to prepare a water-based epoxy resin emulsion with a solid content of 20wt% to 40wt%.

According to the above scheme, the relative molecular mass of the polyethylene glycol monomethyl ether is between 1200 and 2000.

According to the above scheme, the catalyst described in step 2) is any one of boron trifluoride complex, triphenylphosphine and aluminum trichloride.

According to the above scheme, the bisphenol A epoxy resin described in step 2) is any one of E-44 epoxy resin, E-54 epoxy resin and E-51 epoxy resin.

According to the above scheme, the co-solvent described in step 3) is any one of propylene glycol methyl ether, propylene glycol butyl ether and propylene glycol methyl ether acetate.

According to the above scheme, the liquid epoxy resin described in step 3) is E-44 epoxy resin or E-51 epoxy resin.

The basic principle of the present invention is that the epoxy group and the hydroxyl group can undergo addition reaction under the conditions of high temperature and catalyst. Through this reaction, the hydrophilic non-ionic segment and the lipophilic epoxy resin segment are linked to form a macromolecule. The nonionic water-based epoxy resin emulsifier molecule of the present invention contains both hydrophilic nonionic chain segments and lipophilic groups, which can participate in the emulsification reaction of epoxy resin. Using this emulsifier to emulsify epoxy resin has good stability, and it can be prepared and used immediately. The appearance and mechanical properties of the paint film are better. The method is simple, easy to implement, has broad application prospects, considerable economic benefits and great practical application value. The water-based epoxy resin emulsion obtained by the method has good stability, is non-toxic, and has zero organic volatile content (VOC); and the water-based epoxy paint prepared by the method has the characteristics of flexibility and good water resistance.

The beneficial effects of the present invention are: the epoxy resin emulsion emulsified with the non-ionic water-based epoxy resin emulsifier has good stability, is non-toxic, has zero volatile organic matter (VOC) content, is safe and environmentally friendly, and maintains the epoxy resin At the same time, the introduction of non-ionic segments increases the flexibility of the paint film. The invention solves the shortcomings of low stability of the current water-based epoxy resin prepared by the ionization modification technology and poor flexibility and water resistance of the cured coating film.

The nonionic water-based epoxy resin emulsion of the present invention is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The main properties of the water-based epoxy coating are as follows:

1. Stability:

⑴ Centrifugal stability: 2500r/min, no delamination and no demulsification in 30 minutes;

⑵Storage stability: no delamination and no demulsification for 2 months;

(3) Average particle size: <0.5μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 5, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 36h, no blistering, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10% NaOH, 8h, no foaming, no shedding.

Detailed ways

In order to better understand the present invention, the present invention will be further described in detail below in conjunction with examples, but the scope of protection claimed by the present invention is not limited to the scope of implementation representation.

Example 1

A preparation method for reactive epoxy resin emulsion, it comprises the steps:

1) Synthesis of Polyethylene Glycol Monomethyl Ether Epoxy Resin Emulsifier

In a four-necked flask with a water separator and a reflux condenser, add 20g E-44 type epoxy resin, 54g polyethylene glycol monomethyl ether (relative molecular mass 1200), 57.85g toluene, and heat up under magnetic stirring. Azeotropic dehydration was carried out at a temperature of 130-150°C for 3 hours to obtain a mixed liquid, and the temperature was lowered to 85°C, then a solution of 56.25 mg of boron trifluoride complex dissolved in 8.66 g of toluene was added to the above 131.85 g of the mixed liquid, nitrogen Reaction under protection, the epoxy retention rate of the analysis system is sampled every 0.5h during the reaction, when the epoxy retention rate reaches 50%, add water to destroy the catalyst to stop the reaction, decompression distillation to remove the solvent to obtain a colorless transparent viscous liquid, which is Polyethylene glycol monomethyl ether epoxy resin emulsifier;

2) Preparation of water-based epoxy resin emulsion

Add 30g E-44 type epoxy resin and 7.5g propylene glycol methyl ether into a 250mL beaker, stir to reduce the viscosity of the epoxy resin, then add 12g polyethylene glycol monomethyl ether epoxy resin emulsifier, the system is heated to 60 °C, 90.5 g of distilled water was added dropwise under high-speed stirring to prepare a water-based epoxy resin emulsion with a solid content of 30 wt%.

The water-based epoxy resin emulsion of this embodiment is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The stability of waterborne epoxy coatings is as follows:

1. Stability

⑴Centrifugal stability: 2000r/min, 30min without delamination and demulsification;

⑵Storage stability: no delamination and no demulsification for 2 months;

(3) Average particle size: <0.5μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 5, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 36h, no blistering, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10% NaOH, 8h, no foaming, no falling off.

Example 2

A preparation method for reactive epoxy resin emulsion, it comprises the steps:

1) Synthesis of Polyethylene Glycol Monomethyl Ether Epoxy Resin Emulsifier

In a four-necked flask with a water separator and a reflux condenser, add 20g of E-51 epoxy resin, 64g of polyethylene glycol monomethyl ether (relative molecular mass: 1200), and 47.63g of toluene. Raise the temperature under magnetic stirring, azeotropic dehydration at a temperature of 130-150°C for three hours to obtain a mixed liquid, lower the temperature to 85°C, add a solution of 56.25 mg triphenylphosphine dissolved in 8.66 g toluene to the above mixed liquid, and protect it under nitrogen The next reaction. During the reaction, take samples every 0.5h to analyze the epoxy retention rate of the system. When the epoxy retention rate reaches 50%, add water to destroy the catalyst to stop the reaction, and distill the solvent under reduced pressure to obtain a colorless transparent viscous liquid, which is polyethylene glycol Monomethyl ether epoxy resin emulsifier;

2) Preparation of water-based epoxy resin emulsion

Add 30g E-51 type epoxy resin and 4.5g propylene glycol methyl ether into a 250mL beaker, stir to reduce the viscosity of the epoxy resin, then add 14g polyethylene glycol monomethyl ether epoxy resin emulsifier, the system is heated to 60 °C, 98.2 g of distilled water was added dropwise under high-speed stirring to prepare a water-based epoxy resin emulsion with a solid content of 30 wt%.

The water-based epoxy resin emulsion of this embodiment is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The stability of waterborne epoxy coatings is as follows:

1. Stability

⑴ Centrifugal stability: 2500r/min, no delamination and no demulsification in 30 minutes;

⑵Storage stability: no delamination and no demulsification for 3 months;

(3) Average particle size: <0.4μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 5, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 48h, no foaming, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10% NaOH, 8h, no foaming, no falling off.

Example 3

A preparation method for reactive epoxy resin emulsion, it comprises the steps:

1) Synthesis of Polyethylene Glycol Monomethyl Ether Epoxy Resin Emulsifier

In a four-necked flask with a water separator and a reflux condenser, add 10g of E-44 epoxy resin, 45.3g of polyethylene glycol monomethyl ether (relative molecular mass about 2000) and 61.14g of toluene. Raise the temperature under magnetic stirring, azeotropic dehydration at a temperature of 130-150°C for three hours to obtain a mixed liquid, cool down to 90°C, and add a solution of 56.25mg of boron trifluoride complex in 8.66g of toluene to the above mixed liquid , reacted under nitrogen protection. During the reaction period, take samples every 0.5h to analyze the epoxy retention rate of the system. When the epoxy retention rate reaches about 50%, add water to destroy the catalyst to stop the reaction, and distill the solvent under reduced pressure to obtain a white solid, which is polyethylene glycol monomethyl ether Epoxy resin emulsifier;

2) Preparation of water-based epoxy resin emulsion

Add 30g E-44 type epoxy resin and 7.5g propylene glycol methyl ether into a 250mL beaker, stir to reduce the viscosity of the epoxy resin, then add 14g polyethylene glycol monomethyl ether epoxy resin emulsifier, the system is heated to 60 °C, 95.2 g of distilled water was added dropwise under high-speed stirring to prepare a water-based epoxy resin emulsion with a solid content of 30 wt%.

The water-based epoxy resin emulsion of this embodiment is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The stability of waterborne epoxy coatings is as follows:

1. Stability

⑴Centrifugal stability: 2000r/min, 30min without delamination and demulsification;

⑵Storage stability: no delamination and no demulsification for 2 months;

(3) Average particle size: <0.5μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 5, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 36h, no blistering, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10%NaOH, 12h, no foaming, no shedding.

Example 4

A preparation method for reactive epoxy resin emulsion, it comprises the steps:

1) Synthesis of Polyethylene Glycol Monomethyl Ether Epoxy Resin Emulsifier

In a four-necked flask with a water separator and a reflux condenser, add 20g of E-20 type epoxy resin, 39g of polyethylene glycol monomethyl ether (relative molecular mass 2000) and 56.72g of toluene. Raise the temperature under magnetic stirring, azeotropic dehydration at 140°C for three hours to obtain a mixed liquid, lower the temperature to 95°C, add a solution of 56.25g of boron trifluoride complex dissolved in 8.66g of toluene to the above mixed liquid, nitrogen React under protection. During the reaction period, take samples every 0.5h to analyze the epoxy retention rate of the system. When the epoxy retention rate reaches about 50%, add water to destroy the catalyst to stop the reaction, and distill the solvent under reduced pressure to obtain a white solid, which is polyethylene glycol monomethyl ether Epoxy resin emulsifier;

2) Preparation of water-based epoxy resin emulsion

Add 30g E-44 type epoxy resin and 7.5g propylene glycol methyl ether into a 250mL beaker, stir to reduce the viscosity of the epoxy resin, then add 15g polyethylene glycol monomethyl ether epoxy resin emulsifier, the system is heated to 60 °C, 97.5 g of distilled water was added dropwise under high-speed stirring to prepare a water-based epoxy resin emulsion with a solid content of 30 wt%.

The water-based epoxy resin emulsion of this embodiment is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The stability of waterborne epoxy coatings is as follows:

1. Stability

⑴ Centrifugal stability: 2000r/min, no delamination and no demulsification in 20 minutes;

⑵Storage stability: no delamination and no demulsification for 2 months;

(3) Average particle size: <0.6μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 4, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 24h, no blistering, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10% NaOH, 6h, no foaming, no shedding.

Example 5

A preparation method for reactive epoxy resin emulsion, it comprises the steps:

1) Synthesis of Polyethylene Glycol Monomethyl Ether Epoxy Resin Emulsifier

In a four-necked flask with a water separator and a reflux condenser, add 10g of E-51 type epoxy resin, 49.7g of polyethylene glycol monomethyl ether (relative molecular mass 2000) and 70.15g of toluene. Raise the temperature under magnetic stirring, azeotropic dehydration at a temperature of 130-150°C for three hours to obtain a mixed liquid, cool down to 85-95°C, and add a solution of 56.25mg of boron trifluoride complex in 8.66g of toluene to the above mixture In the liquid, react under the protection of nitrogen. During the reaction period, take samples every 0.5h to analyze the epoxy retention rate of the system. When the epoxy retention rate reaches about 50%, add water to destroy the catalyst to stop the reaction, and distill the solvent under reduced pressure to obtain a white solid, which is polyethylene glycol monomethyl ether Epoxy resin emulsifier;

2) Preparation of water-based epoxy resin emulsion

Add 30g E-51 type epoxy resin and 4.5g propylene glycol methyl ether into a 250mL beaker, stir to reduce the viscosity of the epoxy resin, then add 15g polyethylene glycol monomethyl ether epoxy resin emulsifier, the system is heated to 60°C, 100.5 g of distilled water was added dropwise under high-speed stirring to prepare a water-based epoxy resin emulsion with a solid content of 30 wt%.

The water-based epoxy resin emulsion of this embodiment is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The stability of waterborne epoxy coatings is as follows:

1. Stability

⑴Centrifugal stability: 2000r/min, 30min without delamination and demulsification;

⑵Storage stability: no delamination and no demulsification for 2 months;

(3) Average particle size: <0.5μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 5, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 36h, no blistering, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10% NaOH, 8h, no foaming, no falling off.

Example 6

A preparation method for reactive epoxy resin emulsion, it comprises the steps:

1) Synthesis of Polyethylene Glycol Monomethyl Ether Epoxy Resin Emulsifier

In a four-necked flask with a water separator and a reflux condenser, add 20g of E-44 epoxy resin, 54g of polyethylene glycol monomethyl ether (relative molecular mass 1500) and 57.84g of toluene. Raise the temperature under magnetic stirring, azeotropic dehydration at a temperature of 130-150°C for three hours to obtain a mixed liquid, lower the temperature to 85-95°C, dissolve 80mg of catalyst (aluminum trichloride) in 8.66g of toluene and add to the above-mentioned mixed liquid. During the reaction period, samples were taken every 0.5h to analyze the epoxy retention rate of the system. When the epoxy retention rate reached about 50%, water was added to destroy the catalyst to stop the reaction, and the solvent was distilled off under reduced pressure to obtain a colorless transparent viscous liquid, which was polyethylene glycol. Alcohol monomethyl ether epoxy resin emulsifier.

2) Preparation of water-based epoxy resin emulsion

Add 30g E-44 type epoxy resin and 7.5g propylene glycol methyl ether into a 250mL beaker, stir to reduce the viscosity of the epoxy resin, then add 15g polyethylene glycol monomethyl ether epoxy resin emulsifier, the system is heated to 60 °C, 97.5g distilled water was added dropwise under high-speed stirring to make a water-based epoxy resin emulsion with a solid content of 30 wt%.

The water-based epoxy resin emulsion of this embodiment is added into a water-based epoxy curing agent to prepare a water-based epoxy coating. The stability of waterborne epoxy coatings is as follows:

1. Stability

⑴Centrifugal stability: 2000r/min, 30min without delamination and demulsification;

⑵Storage stability: no delamination and no demulsification for 2 months;

(3) Average particle size: <0.5μm;

2. Adhesion: Class I, GB/T 1725-89 "Determination of Paint Film Adhesion";

3. Flexibility: ≥ grade 5, GB/T 1748-89 "Determination of Flexibility of Paint Film";

4. Water resistance: 25 ℃, 36h, no blistering, no falling off, GB1733-79(88) "Determination of Water Resistance of Paint Film";

5. Alkali resistance: 10% NaOH, 8h, no foaming, no falling off.

Claims (5)

1. a preparation method of aqueous epoxy resin emulsion, is characterized in that comprising the following steps: 1) According to the mass percentage of each raw material: bisphenol A epoxy resin 7% ~ 24%, polyethylene glycol monomethyl ether 30% ~ 50% and toluene 30% ~ 55%, choose bisphenol A epoxy resin , Polyethylene glycol monomethyl ether and toluene, standby; The relative molecular mass of the polyethylene glycol monomethyl ether is between 1200～2000; Under the protection of nitrogen, mix bisphenol A epoxy resin, polyethylene glycol monomethyl ether and toluene, heat up under magnetic stirring, and azeotropically dehydrate at a temperature of 130-150°C for 2.5-3 hours to obtain a mixed liquid; 2) According to the mass percentage of each raw material: mixed liquid 90%-94.95%, toluene 5%-9.95% and catalyst 0.03%-0.06%, select the mixed liquid, toluene and catalyst obtained in step 1) and set aside; Dissolve the catalyst in toluene, then add it to the mixed liquid obtained in step 1), raise the temperature under magnetic stirring, and strictly control the reaction at a temperature of 85-95°C under the protection of nitrogen. During the reaction, take samples regularly to analyze the epoxy value of the system. Calculate bisphenol A epoxy resin epoxy retention rate, when the retention rate of bisphenol A epoxy resin epoxy drops to 50%, decompression steams and removes solvent, obtains reactive nonionic epoxy emulsifier; 3) According to the mass percentage of each raw material: liquid epoxy resin 18%-22%, reactive non-ionic epoxy emulsifier 8%-10%, distilled water 64%-70% and co-solvent 4%-5% , choose liquid epoxy resin, reactive nonionic epoxy emulsifier, distilled water and co-solvent obtained in step 2), and set aside; Under strong stirring of liquid epoxy resin, co-solvent, and reactive nonionic epoxy emulsifier, distilled water is added dropwise to prepare a water-based epoxy resin emulsion with a solid content of 20wt% to 40wt%. 2. by the preparation method of the described aqueous epoxy resin emulsion of claim 1, it is characterized in that step 2) described catalyst is any one in boron trifluoride complex, triphenylphosphine and aluminum trichloride kind. 3. by the preparation method of the described aqueous epoxy resin emulsion of claim 1, it is characterized in that step 2) described bisphenol A epoxy resin is E-44 type epoxy resin, E-54 type epoxy resin and Any one of the E-51 type epoxy resins. 4. by the preparation method of the described aqueous epoxy resin emulsion of claim 1, it is characterized in that step 3) described co-solvent is any one in propylene glycol methyl ether, propylene glycol butyl ether and propylene glycol methyl ether acetate. 5. The preparation method of the water-based epoxy resin emulsion according to claim 1, characterized in that the liquid epoxy resin described in step 3) is E-44 type epoxy resin or E-51 type epoxy resin.