CN105713181B - Water paint self-emulsifying epoxy resin emulsion and preparation method thereof - Google Patents

Abstract

The invention relates to a self-emulsifying epoxy resin emulsion for water-based paint, which comprises the following components in weight percent: 40% to 75% of modified epoxy resin, 25% to 60% of deionized water; the modified epoxy resin It is made of the following raw materials in weight percentage: epoxy resin 20%~50%, polyether polyol 10%~30%, alkylphenol polyoxyethylene ether 1%~15%, C12~C14 alkyl glycidyl ether ring Oxygen resin 2%~15%, chain extender 5%~20%, catalyst 0.16%~0.4%, organic solvent 20%~50%. The self-emulsifying epoxy resin emulsion of the present invention has good storage stability, good compatibility with the matching water-emulsion epoxy curing agent, and excellent paint film performance.

Description

Self-emulsifying epoxy resin emulsion for water-based paint and preparation method thereof

technical field

The invention relates to a self-emulsifying epoxy resin emulsion for water-based paint and a preparation method thereof.

Background technique

Epoxy resin has the advantages of good bonding performance, good stability of cured product, high mechanical strength, low shrinkage rate and water absorption, excellent electrical insulation performance, etc., so it is widely used in coatings, adhesives and polymer manufacturing industries. Epoxy resin coatings are one of the pillar products of the coatings industry. According to reports, the amount of epoxy resin used in coatings in my country accounts for about 40% of the total amount of epoxy resin. It is expected that the domestic epoxy resin industry will continue to grow steadily in the future. On the one hand, the global industrial transfer has led to the transfer of downstream industries such as electronics and ships to China for production, which has stimulated the demand for epoxy resin; on the other hand, the quality of products produced by domestic enterprises is constantly improving, and they are gradually comparable Advantage. However, traditional epoxy resins are only soluble in organic solvents such as aromatic hydrocarbons and ketones. The topic of substituting "water" for "oil" in the coatings industry has been widely discussed. Since February 1, 2015, the national policy of imposing a 4% consumption tax on coatings with a VOC content of more than 420 g/L has been implemented. Traditional solvent-based industries The process of transformation and upgrading of paint companies to the direction of water-based, powder and other environmental protection has been irreversible.

The water-based technology of epoxy resin has experienced the development process from the emulsifier method to the self-emulsification method. Generally speaking, the external emulsifier method mainly refers to the mechanical method and the phase inversion method, and the waterborne epoxy resin prepared by this method belongs to the first generation of waterborne epoxy resin system. In 2002, Shi Xuezhen and others from Shanghai Lvjia Water-based Coatings Co., Ltd. reported a method for preparing a water-based epoxy emulsion. The technical key point is to prepare a reactive emulsifier, and then combine the phase inversion method to prepare a water-based epoxy emulsion. . However, the external emulsifier method generally has the disadvantages of poor chemical resistance of the paint film, low molecular weight of the cured product, and easy extraction from the paint film.

The water-based epoxy emulsion prepared by emulsifying oil-soluble epoxy resin with water-soluble curing agent belongs to the second generation of water-based epoxy system. Zhou Jiliang and others reported the synthesis of a non-ionic water-based epoxy curing agent, which has a good function of emulsifying liquid epoxy resin at room temperature, and the two-component water-based epoxy coating prepared by it is cured at room temperature Finally, a coating film with excellent performance is obtained, which has good flexibility and impact resistance. However, the initial viscosity of the system is high, the construction period is short, and the curing speed is slow, which brings certain difficulties to the actual engineering construction.

The self-emulsification method is the chemical modification method, which uses active reactive groups on the epoxy resin, such as epoxy groups, secondary hydroxyl groups, methylene hydrogen, etc., to incorporate hydrophilic groups (amino groups, polyoxyethylene segments, Carboxyl group) is introduced into the molecular structure of epoxy resin, so that the epoxy resin has hydrophilic and lipophilic amphiphilic properties. The technology of various water-based epoxy products launched in China before is still on the second generation of water-based epoxy products, and the performance of the prepared coating products is far from the performance of solvent-based coating products. After searching, it is found that the Chinese patent No. 2006100498972 discloses a kind of epoxy acrylic emulsifier and the preparation method of the acrylic epoxy emulsion prepared by emulsifying acrylic epoxy ester monomers by the emulsifier. The method adopts toluene diisocyanate or Triphenylphosphine is used as a coupling agent, and toluene diisocyanate will react with raw materials and moisture in the air at room temperature, and many side reactions lead to impure products, and not only the raw materials need to be dehydrated, but the free isocyanate is harmful to the environment and the paint film. The performance will cause adverse effects, and the present invention only prepares an emulsifier, and then prepares an emulsion from the emulsifier emulsifying monomer, which still belongs to the category of the first generation of water-based epoxy introduced above; the Chinese patent number 2008100274947 The patent discloses a preparation method of a non-ionic solid epoxy resin and its emulsion. This method is catalyzed by LEWIS acid boron trifluoride ether, and a polyether segment is inserted into the epoxy resin molecule, thereby realizing epoxy resin Water-based resin, but the LEWIS acid catalyst is difficult to remove after the reaction is completed, and it will corrode the equipment after long-term use. The most important thing is to use boron trifluoride ether as the catalyst. The reaction is relatively violent, which will trigger the self-polymerization of epoxy groups. The reaction is not easy to control.

Contents of the invention

The purpose of the present invention is to: aim at the problem that above-mentioned prior art exists, propose a kind of self-emulsifying epoxy resin emulsion for water-based paint, provide its preparation method simultaneously.

In order to achieve the above purpose, a technical solution of the present invention provides

The self-emulsifying epoxy resin emulsion for water-based paint of the present invention comprises the following components in weight percent: 40% to 75% of modified epoxy resin, 25% to 60% of deionized water; the modified epoxy resin consists of the following Made of raw materials in weight percentage: epoxy resin 20%~50%, polyether polyol 10%~30%, alkylphenol polyoxyethylene ether 1%~15%, C12~C14 alkyl glycidyl ether epoxy resin 2%~15%, chain extender 5%~20%, catalyst 0.16%~0.4%, organic solvent 20%~50%.

The modified epoxy resin of the present invention refers to grafting hydrophilic substances such as alkylphenol polyoxyethylene ether and polyether polyol on the water-insoluble epoxy resin molecular structure, and alkylphenol polyoxyethylene ether itself can be used as An emulsifier is used, and the modified epoxy resin obtained by grafting alkylphenol polyoxyethylene ether into epoxy resin has a self-emulsifying function. In addition, the C12-C14 alkyl glycidyl ether epoxy resin with small molecules can be used not only as a diluent for macromolecular epoxy resins such as E-20, E-44, E-51, etc., but also as a diluent that participates in the reaction. Epoxy resin is used (epoxy resin is one or more of E-20, E-44, E-51, C12-C14 alkyl glycidyl ether epoxy resin), avoiding the use of a large amount of organic solvents, reasonable The viscosity of the reaction is controlled to ensure that the reaction will not be stirred unevenly due to excessive viscosity, thereby avoiding gelation during the preparation process.

Preferably, the modified epoxy resin is made of the following raw materials in weight percentage: 20% to 50% of epoxy resin, 20% to 30% of polyether polyol, 1% to 5% of alkylphenol polyoxyethylene ether , C12~C14 alkyl glycidyl ether epoxy resin 2%~5%, chain extender 5%~20%, catalyst 0.16%~0.4%, organic solvent 20%~50%.

Preferably, the modified epoxy resin is made of the following raw materials in weight percentage: 20% to 50% of epoxy resin, 15% to 20% of polyether polyol, 5% to 10% of alkylphenol polyoxyethylene ether , C12~C14 alkyl glycidyl ether epoxy resin 5%~10%, chain extender 5%~20%, catalyst 0.16%~0.4%, organic solvent 20%~50%.

Preferably, the modified epoxy resin is made of the following raw materials in weight percentage: 20% to 50% of epoxy resin, 10% to 15% of polyether polyol, 10% to 15% of alkylphenol polyoxyethylene ether , C12~C14 alkyl glycidyl ether epoxy resin 10%~15%, chain extender 5%~20%, catalyst 0.16%~0.4%, organic solvent 20%~50%.

Preferably, the epoxy resin is one or more of E-20, E-44, E-51, C12～C14 alkyl glycidyl ether epoxy resins; the polyether polyol is preferably polyethylene glycol Alcohol, the polyethylene glycol has a molecular weight of 400-1000; the alkylphenol polyoxyethylene ether is one or both of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether.

Further preferably, the C12-C14 alkyl glycidyl ether epoxy resin is a reactive diluent AGE or a reactive diluent BGE.

Preferably, the chain extender is one or more of phthalic anhydride, methyl tetrahydrophthalic anhydride, and methyl hexahydrophthalic anhydride; the catalyst is a quaternary ammonium salt catalyst, and the quaternary ammonium salt catalyst is preferably Tetrabutylammonium bromide; The organic solvent is one or more of propylene glycol butyl ether, propylene glycol methyl ether, and n-butanol.

In order to achieve above object, the present invention also provides the preparation method of self-emulsifying epoxy resin emulsion for water-based paint, it is characterized in that, comprises the following steps:

1. Preparation of modified epoxy resin:

(1) Add 5% to 20% of the chain extender and 1/2 of the 20% to 50% organic solvent into the container according to the weight percentage of the required raw materials. After stirring evenly, raise the temperature to 105±15°C and proceed to the next step ;

(2) Take 10%~30% polyether polyol and 1%~15% alkylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them evenly to obtain a mixture, then add the mixture dropwise into the container, and the time of adding the mixture is controlled After 1-2 hours, after the mixture is added dropwise, keep it warm at 105±15°C for 2-3 hours to obtain a prepolymer, pour out the prepolymer for later use, and proceed to the next step;

(3) One-half of 20% to 50% organic solvent, 0.16% to 0.4% catalyst, 20% to 50% epoxy resin and 2% to 15% C12 to C14 alkyl shrinkage according to the weight percentage of the required raw materials Add the glyceryl ether epoxy resin into the container, stir it evenly and then raise the temperature to 120±10°C, then add the prepolymer dropwise to the container, and the time for adding the prepolymer is controlled at 2±0.5h. Insulate at 120±10°C for 2 to 4 hours, and distill under reduced pressure to obtain modified epoxy resin;

2. Preparation of self-emulsifying epoxy resin emulsion:

Add 40%~75% modified epoxy resin to the container according to the weight percentage of the required components, and then add 25%~60% to the container dropwise at a temperature of 50±5°C and a speed of 1000~1200r/min. The time for adding ionized water and deionized water is controlled within 0.5 to 1 hour. After the addition of deionized water is completed, stir evenly at a speed of 300±50r/min to obtain a self-emulsifying epoxy resin emulsion.

The advantage of the preparation method of the present invention is that in the process of preparing the self-emulsifying epoxy resin emulsion, no external emulsifier is needed, and the oil-soluble epoxy resin is modified to realize its own emulsification, and the self-emulsifying epoxy resin emulsion The particle size is 100-200nm, and the blue light is obvious. It can be cured quickly at room temperature with the water-emulsion epoxy curing agent commonly used in the market, and the paint film has good performance.

Preferably, the epoxy resin is one or more of E-20, E-44, E-51, C12～C14 alkyl glycidyl ether epoxy resins; the polyether polyol is preferably polyethylene glycol Alcohol, the polyethylene glycol has a molecular weight of 400-1000; the alkylphenol polyoxyethylene ether is one or both of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether.

Preferably, the chain extender is one or more of phthalic anhydride, methyl tetrahydrophthalic anhydride, and methyl hexahydrophthalic anhydride; the catalyst is a quaternary ammonium salt catalyst, and the quaternary ammonium salt catalyst is preferably Tetrabutylammonium bromide; The organic solvent is one or more of propylene glycol butyl ether, propylene glycol methyl ether, and n-butanol. This patent selects acid anhydrides that are not prone to side reactions as chain extenders, and can introduce polyoxyethylene ether segments into the molecular structure of epoxy resins without catalyst action, and modify oily epoxy into self-emulsifying water-based epoxy resins. oxygen.

The advantages of the invention are: the self-emulsifying epoxy resin emulsion of the invention has good storage stability, good compatibility with matching water-emulsion epoxy curing agents, and excellent paint film performance.

Detailed ways

The chemical reagents and materials used in the present invention are commercially available. Among them, the model of reactive diluent AGE is 748, purchased from Foshan Hongshuo Chemical Co., Ltd.; the model of reactive diluent BGE is 501, purchased from Foshan Hongshuo Chemical Co., Ltd.

Embodiment one

Preparation of modified epoxy resin:

Take 1/2 of 5% phthalic anhydride and 20% propylene glycol methyl ether according to the weight percentage of the required raw materials and add it to a four-necked flask equipped with a stirrer, a thermometer and a condensing device. After stirring evenly, slowly heat up to 105 ℃. Then first take 30% polyethylene glycol 400 and 15% nonylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them evenly to obtain a mixture, then add the mixture dropwise into a four-necked flask, and the time for adding the mixture is controlled at 1h. After the dropwise addition of the mixture was completed, the mixture was incubated at 105° C. for 2 hours to obtain a prepolymer, which was poured out for use. Add one-half of the remaining 20% propylene glycol methyl ether, 0.16% tetrabutylammonium bromide, 20% epoxy resin E-51 and 9.84% reactive diluent AGE into the four-necked flask according to the weight percentage of the required raw materials After stirring evenly, slowly raise the temperature to 120°C, and add the prepolymer dropwise to the container. The time for adding the prepolymer is controlled at 2h. epoxy resin.

To prepare a self-emulsifying epoxy resin emulsion:

Add 40% modified epoxy resin to the four-necked flask according to the weight percentage of the required components, and then add 60% deionized water to the container dropwise at a temperature of 50°C and a speed of 1000r/min, and the time of adding the deionized water is controlled. In 1 h, after the deionized water was added dropwise, the mixture was stirred evenly at a speed of 300 r/min to obtain a self-emulsifying epoxy resin emulsion.

Embodiment two

Preparation of modified epoxy resin:

Take 1/2 of 6.6% methyl tetrahydrophthalic anhydride and 30% propylene glycol butyl ether according to the weight percentage of the required raw materials and add it to a four-necked flask equipped with a stirrer, a thermometer and a condensing device. After stirring evenly, slowly heat up to 120 ℃. Then first take 10% polyethylene glycol 600 and 1% octylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them uniformly to obtain a mixture, then add the mixture dropwise to a four-necked flask, and the time for adding the mixture is controlled at 2h. After the dropwise addition of the mixture was completed, the mixture was incubated at 120° C. for 3 hours to obtain a prepolymer, which was poured out for later use. Add one-half of the remaining 30% propylene glycol butyl ether, 0.4% tetrabutylammonium bromide, 50% epoxy resin E-20 and 2% active diluent BGE into the four-necked flask according to the weight percentage of the required raw materials After stirring evenly, the temperature was raised slowly to 130°C, and the prepolymer was added dropwise to the container. The time for adding the prepolymer was controlled at 2.5 hours. permanent epoxy resin.

To prepare a self-emulsifying epoxy resin emulsion:

Add 40% modified epoxy resin to the four-necked flask according to the weight percentage of the required components, and then add 60% deionized water to the container dropwise at a temperature of 55°C and a speed of 1050r/min, and the time of adding the deionized water is controlled. In 0.5 h, after the deionized water was added dropwise, the mixture was stirred evenly at a speed of 350 r/min to obtain a self-emulsifying epoxy resin emulsion.

Embodiment Three

Preparation of modified epoxy resin:

Take 1/2 of 20% methyl hexahydrophthalic anhydride and 20% n-butanol according to the weight percentage of the required raw materials and add it to a four-necked flask equipped with a stirrer, a thermometer and a condensing device. After stirring evenly, slowly heat up to 100 ℃. Then first take 15% polyethylene glycol 800 and 9.72% nonylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them evenly to obtain a mixture, then add the mixture dropwise into a four-necked flask, and the time for adding the mixture is controlled at 1.5h , after the dropwise addition of the mixture was completed, the mixture was incubated at 100° C. for 2.5 hours to obtain a prepolymer, and the prepolymer was poured out for use. Add one-half of the remaining 20% n-butanol, 0.28% tetrabutylammonium bromide, 30% epoxy resin E-44 and 5% reactive diluent AGE into the four-necked flask according to the weight percentage of the required raw materials , after stirring evenly, slowly raise the temperature to 110°C, and add the prepolymer dropwise to the container. The time for adding the prepolymer is controlled at 1.5h. permanent epoxy resin.

To prepare a self-emulsifying epoxy resin emulsion:

Add 40% modified epoxy resin to the four-necked flask according to the weight percentage of the required components, and then add 60% deionized water to the container dropwise at a temperature of 45°C and a speed of 1200r/min, and the time of adding the deionized water is controlled. In 1 h, after the deionized water was added dropwise, the mixture was stirred evenly at a speed of 300 r/min to obtain a self-emulsifying epoxy resin emulsion.

Embodiment four

Preparation of modified epoxy resin:

Take 1/2 of 10% phthalic anhydride and 50% propylene glycol methyl ether according to the weight percentage of the required raw materials and add it to a four-necked flask equipped with a stirrer, a thermometer and a condensing device. After stirring evenly, slowly heat up to 90 ℃. Then first take 12.78% polyethylene glycol 1000 and 5% octylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them uniformly to obtain a mixture, then add the mixture dropwise into a four-necked flask, and the time for adding the mixture is controlled at 2h. After the dropwise addition of the mixture was completed, the mixture was incubated at 90° C. for 3 hours to obtain a prepolymer, which was poured out for use. Add one-half of the remaining 50% propylene glycol methyl ether, 0.22% tetrabutylammonium bromide, 20% AGE and 2% active diluent BGE into the four-necked flask according to the weight percentage of the required raw materials, stir well and slowly The temperature was raised to 120°C, and the prepolymer was added dropwise to the container. The time for adding the prepolymer was controlled at 2 hours. After the dropwise addition of the prepolymer was completed, it was kept at 120°C for 4 hours, and the modified epoxy resin was obtained by distillation under reduced pressure.

To prepare a self-emulsifying epoxy resin emulsion:

Add 40% modified epoxy resin to the four-necked flask according to the weight percentage of the required components, and then add 60% deionized water to the container dropwise at a temperature of 50°C and a speed of 1100r/min, and the time of adding the deionized water is controlled. In 1 hour, after the deionized water was added dropwise, the mixture was stirred evenly at a rotational speed of 250 r/min to obtain a self-emulsifying epoxy resin emulsion.

Embodiment five

Preparation of modified epoxy resin:

Take 1/2 of 14.66% methyl tetrahydrophthalic anhydride and 20% n-butanol according to the weight percentage of the required raw materials and add it to a four-necked flask equipped with a stirrer, a thermometer and a condensing device. After stirring evenly, slowly heat up to 115 ℃. Then first take 20% polyethylene glycol 800 and 10% octylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them evenly to obtain a mixture, then add the mixture dropwise into a four-necked flask, and the time for adding the mixture is controlled at 1.5h , after the dropwise addition of the mixture was completed, the mixture was incubated at 115° C. for 2.5 hours to obtain a prepolymer, and the prepolymer was poured out for use. Add one-half of the remaining 20% n-butanol, 0.34% tetrabutylammonium bromide, 20% BGE and 15% reactive diluent AGE into the four-necked flask according to the weight percentage of the required raw materials, stir well and slowly The temperature was raised to 125°C, and the prepolymer was added dropwise to the container. The time for adding the prepolymer was controlled at 2 hours. After the dropwise addition of the prepolymer was completed, it was kept at 125°C for 3 hours, and the modified epoxy resin was obtained by distillation under reduced pressure.

To prepare a self-emulsifying epoxy resin emulsion:

Add 40% modified epoxy resin to the four-necked flask according to the weight percentage of the required components, and then add 60% deionized water to the container dropwise at a temperature of 55°C and a speed of 1200r/min, and the time of adding the deionized water is controlled. In 1 h, after the deionized water was added dropwise, the mixture was stirred evenly at a speed of 300 r/min to obtain a self-emulsifying epoxy resin emulsion.

In addition to the above-mentioned embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims (5)

1. Self-emulsifying epoxy resin emulsion for water-based coatings, characterized in that it comprises the following components in weight percent: 40% to 75% of modified epoxy resin, 25% to 60% of deionized water; The resin is made of the following raw materials by weight percentage: epoxy resin 20%-50%, polyether polyol 10%-30%, alkylphenol polyoxyethylene ether 1%-15%, C12-C14 alkyl glycidyl ether 2%-15% epoxy resin, 5%-20% chain extender, 0.16%-0.4% catalyst, 20%-50% organic solvent; the epoxy resin is E-20, E-44, E-51 One or more of them; the polyether polyol is polyethylene glycol, and the molecular weight of the polyethylene glycol is 400 to 1000; the alkylphenol polyoxyethylene ether is nonylphenol polyoxyethylene ether , one or both of octylphenol polyoxyethylene ether; the C12～C14 alkyl glycidyl ether epoxy resin is a reactive diluent AGE; the chain extender is phthalic anhydride, methyl tetra One or more of hydrophthalic anhydride and methyl hexahydrophthalic anhydride; the catalyst is a quaternary ammonium salt catalyst, and the quaternary ammonium salt catalyst is tetrabutylammonium bromide; the organic solvent is propylene glycol butyl ether, propylene glycol methyl One or more of ether and n-butanol. 2. the self-emulsifying epoxy resin emulsion for water-based coatings according to claim 1, is characterized in that, described modified epoxy resin is made of the raw material of following percentage by weight: epoxy resin 20%～50%, polyether Polyol 20%~30%, Alkylphenol Polyoxyethylene Ether 1%~5%, C12~C14 Alkyl Glycidyl Ether Epoxy Resin 2%~5%, Chain Extender 5%~20%, Catalyst 0.16% ～0.4%, organic solvent 20%～50%. 3. The self-emulsifying epoxy resin emulsion for water-based paint according to claim 1, wherein the modified epoxy resin is made of the following raw materials in percentage by weight: 20%～50% of epoxy resin, polyether Polyol 15%~20%, Alkylphenol Polyoxyethylene Ether 5%~10%, C12~C14 Alkyl Glycidyl Ether Epoxy Resin 5%~10%, Chain Extender 5%~20%, Catalyst 0.16% ～0.4%, organic solvent 20%～50%. 4. The self-emulsifying epoxy resin emulsion for water-based paint according to claim 1, characterized in that, the modified epoxy resin is made of the following raw materials in percentage by weight: 20%～50% of epoxy resin, polyether Polyol 10%~15%, Alkylphenol Polyoxyethylene Ether 10%~15%, C12~C14 Alkyl Glycidyl Ether Epoxy Resin 10%~15%, Chain Extender 5%~20%, Catalyst 0.16% ～0.4%, organic solvent 20%～50%. 5. the preparation method of self-emulsifying epoxy resin emulsion for water-based paint according to claim 1, is characterized in that, comprises the following steps: 1. Preparation of modified epoxy resin: (1) Add 5% to 20% chain extender and 1/2 of 20% to 50% organic solvent into the container according to the weight percentage of the required raw materials. After stirring evenly, raise the temperature to 105±15°C and proceed to the next step ; (2) Take 10%-30% polyether polyol and 1%-15% alkylphenol polyoxyethylene ether according to the weight percentage of the required raw materials and mix them evenly to obtain a mixture, then add the mixture dropwise into the container, and the time of adding the mixture is controlled After 1-2 hours, after the mixture is added dropwise, keep it warm at 105±15°C for 2-3 hours to obtain a prepolymer, pour out the prepolymer for later use, and proceed to the next step; (3) One-half of 20% to 50% organic solvent, 0.16% to 0.4% catalyst, 20% to 50% epoxy resin and 2% to 15% C12 to C14 alkyl shrinkage according to the weight percentage of the required raw materials Add the glyceryl ether epoxy resin into the container, stir it evenly and then raise the temperature to 120±10°C, then add the prepolymer dropwise to the container, and the time for adding the prepolymer is controlled at 2±0.5h. Insulate at 120±10°C for 2 to 4 hours, and distill under reduced pressure to obtain modified epoxy resin; 2. Preparation of self-emulsifying epoxy resin emulsion: Add 40%~75% modified epoxy resin into the container according to the weight percentage of the required components, and then add 25%~60% to the container dropwise at a temperature of 50±5°C and a speed of 1000~1200r/min. The time for adding ionized water and deionized water is controlled within 0.5 to 1 hour. After the addition of deionized water is completed, stir evenly at a speed of 300±50r/min to obtain a self-emulsifying epoxy resin emulsion.