A method for preparing a self-emulsifying epoxy resin

Abstract

The application relates to the field of epoxy resin modification, in particular to a preparation method of a self-emulsifying epoxy resin. The method overcomes the defects of the prior art, such as the need to add an emulsifier and mechanical stirring for emulsification, easy demulsification, low epoxy value and the like. The preparation method comprises the following steps: firstly, adding a Lewis acid into a mixed solution of polyethylene glycol and epoxy chloropropane to prepare one-side chlorinated polyethylene glycol; secondly, adding bisphenol A into the one-side chlorinated polyethylene glycol system to make the one-side hydroxyl group of the bisphenol A graft with polyethylene glycol through a Williamson ether reaction under the catalysis of alkali; and thirdly, adding epoxy chloropropane into the bisphenol A solution grafted with one-side polyethylene glycol to make the other-side hydroxyl group of the bisphenol A graft with an epoxy group under the catalysis of alkali, so as to prepare the epoxy resin with self-emulsifying effect. The raw materials of the reaction method are cheap and easy to obtain, the method is simple, the toxicity is relatively small, there is no by-product after the reaction is completed, and the environment pollution is relatively small. The reaction raw material utilization rate is high, the yield is high, the method meets the concept of green paint, and can be widely applied to the industrial production fields of paint and material.

Description

Technical Field

[0001] This invention belongs to the field of materials synthesis technology, and particularly relates to a method for preparing a self-emulsifying epoxy resin. Background Technology

[0002] Epoxy resins are widely used in coatings, adhesive lamination materials, and composite matrix materials due to their excellent physical, mechanical, and electrical insulation properties. Epoxy resins account for a significant proportion of applications in coatings, and can be formulated into various varieties with unique characteristics and applications. Traditional epoxy resins are mostly liquids or semi-solids with poor water solubility, requiring the addition of organic solvents. However, organic solvents are volatile, expensive, and harmful to human health. With the development of modern science and technology and the new concepts and awareness of environmental protection laws and regulations, the development of waterborne epoxy resins has become a social consensus. Waterborne epoxy resins use water as a dispersion medium, which can reduce the content of volatile organic compounds (VOCs), control environmental pollution, reduce fire risks, and improve occupational health and safety. The waterborne methods for epoxy resins are mainly divided into physical and chemical methods. Physical methods mainly achieve water dispersion and emulsification through the addition of emulsifiers, while chemical methods achieve waterborne epoxy resins by introducing hydrophilic groups. Chemical methods are the most commonly used, especially self-emulsification methods.

[0003] Among existing methods for preparing self-emulsifying epoxy resins, directly grafting hydrophilic groups onto the epoxy resin is one of the most direct approaches. This method mostly involves a Lewis acid-catalyzed nucleophilic addition reaction based on E51, causing the epoxy groups on one side of the epoxy resin to react with polyethylene glycol, thereby achieving the grafting of hydrophilic groups. However, this method leads to ring-opening of the epoxy groups on the other side of bisphenol A, resulting in an excessively low epoxy value in the target resin, and also significantly impacts the subsequent curing and crosslinking of the resin. This invention uses bisphenol A as the matrix and, by changing the grafting order of the hydrophilic and lipophilic groups, avoids the destruction of the epoxy groups, obtaining a self-emulsifying epoxy resin with a high epoxy value. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a method for preparing a self-emulsifying epoxy resin. The general structural formula of the self-emulsifying epoxy resin is:

[0005]

[0006] Where n represents the degree of polymerization of polyethylene glycol, the degree of polymerization of polyethylene glycol used in this invention is n = 4, 6, 8, 12, 16, that is, polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 600, and polyethylene glycol 800.

[0007] The present invention provides a method for preparing a self-emulsifying epoxy resin, comprising the following steps:

[0008] I. A catalyst is added to a mixed solution of polyethylene glycol and epichlorohydrin to prepare unilaterally chlorinated polyethylene glycol.

[0009] 2. Bisphenol A is then added to the unilaterally chlorinated polyethylene glycol solution, and under the catalysis of an alkali, a bisphenol A derivative with one side of phenolic hydroxyl group grafted onto polyethylene glycol is generated.

[0010] 3. Add epichlorohydrin to the above system, and under the action of alkali, graft epoxy groups onto the phenolic hydroxyl groups on the other side of bisphenol A to obtain a self-emulsifying epoxy resin.

[0011] Furthermore, the polyethylene glycol is one of polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 600, and polyethylene glycol 800.

[0012] Furthermore, the molar ratio of polyethylene glycol to epichlorohydrin is (1.0-3.0):1, preferably (1.0-1.5):1.

[0013] Furthermore, the catalyst mentioned in step one is one of the Lewis acids such as aluminum chloride, ferric chloride, zinc chloride, copper chloride, and boron trifluoride tetrahydrofuran complex.

[0014] Furthermore, in step two, the molar ratio of the unilaterally chlorinated polyethylene glycol to bisphenol A is (1.0-2.0):1, wherein the preferred molar ratio is (1.0-1.5):1.

[0015] Furthermore, the molar ratio of the alkali to bisphenol A in step two is (1.0-5.0):1, wherein the preferred molar ratio is (2.0-2.3):1.

[0016] Furthermore, the molar ratio of epichlorohydrin to alkali in step three is (1.0-5.0):1, wherein the preferred molar ratio is (2.0-3.0):1.

[0017] Furthermore, the reaction temperature described in step three, i.e., the grafting of epoxy groups onto the phenolic hydroxyl group on the other side of bisphenol A, is carried out at 20-100°C, with a preferred temperature of 70°C.

[0018] Furthermore, in step three, when grafting an epoxy group onto the phenolic hydroxyl group on the other side of bisphenol A, the base is one of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, and potassium carbonate, and the concentration of the base solution is (0.2-1.0) mol / L, preferably (0.3-0.5) mol / L.

[0019] Furthermore, in step three, the molar ratio of epichlorohydrin to the bisphenol A derivative grafted with hydrophilic groups on one side is (1.0-6.0):1, wherein the preferred molar ratio is (4.0-6.0):1.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. This invention starts with polyethylene glycol and uses Lewis acid as a catalyst. Without complicated procedures, it first reacts with epichlorohydrin at room temperature to obtain unilaterally chlorinated polyethylene glycol. Without post-treatment, bisphenol A and a base are directly added to the above system to obtain a product with a hydrophilic group grafted onto one side of the hydroxyl group. Finally, epichlorohydrin and a base are added to the system to graft an epoxy group onto the other side of the hydroxyl group of bisphenol A.

[0022] 2. The raw materials for this invention are inexpensive and readily available, and the operation is simple, making it suitable for large-scale production.

[0023] 3. By changing the grafting order of hydrophilic and lipophilic groups, the present invention first introduces hydrophilic groups, avoiding the problem of low epoxy value caused by the destruction of epoxy groups in the prior art. This allows for the production of epoxy resins with higher epoxy values. For example, the epoxy resin obtained from polyethylene glycol 800 in this invention can achieve an epoxy value of 0.085.

[0024] 4. The self-emulsifying epoxy resin prepared by the present invention has excellent storage stability. For example, the epoxy resin emulsion obtained by the present invention from polyethylene glycol 800 still has good dispersibility and emulsification performance after being stored at room temperature for more than 120 days. Attached Figure Description

[0025] Appendix Figure 1 The image shows the nuclear magnetic resonance spectrum of the self-emulsifying epoxy resin with polyethylene glycol 200 as the hydrophilic end in Example 1.

[0026] Appendix Figure 2 The image shows the nuclear magnetic resonance spectrum of the self-emulsifying epoxy resin with polyethylene glycol 300 as the hydrophilic end in Example 12.

[0027] Appendix Figure 3 The image shows the nuclear magnetic resonance spectrum of the self-emulsifying epoxy resin with polyethylene glycol 400 as the hydrophilic end in Example 13.

[0028] Appendix Figure 4 The image shows the nuclear magnetic resonance spectrum of the self-emulsifying epoxy resin with polyethylene glycol 600 as the hydrophilic end in Example 14.

[0029] Appendix Figure 5 The image shows the nuclear magnetic resonance spectrum of the self-emulsifying epoxy resin with polyethylene glycol 800 as the hydrophilic end in Example 15. Detailed Implementation

[0030] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

[0031] Specific Implementation Method 1: The preparation method of self-emulsifying epoxy resin in this implementation method includes the following steps:

[0032] I. A catalyst is added to a mixed solution of polyethylene glycol and epichlorohydrin to prepare unilaterally chlorinated polyethylene glycol.

[0033] 2. Bisphenol A is then added to the unilaterally chlorinated polyethylene glycol solution, and under the catalysis of an alkali, a bisphenol A derivative with one side of phenolic hydroxyl group grafted onto polyethylene glycol is generated.

[0034] 3. Add epichlorohydrin to the above system, and under the action of alkali, graft epoxy groups onto the phenolic hydroxyl groups on the other side of bisphenol A to obtain a self-emulsifying epoxy resin.

[0035] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the polyethylene glycol is one of PEG200, PEG300, PEG400, PEG600, and PEG800, while the others are the same as in Specific Implementation Method One.

[0036] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One in that the Lewis acid is one of aluminum chloride, ferric chloride, zinc chloride, copper chloride, or a boron trifluoride tetrahydrofuran complex. Everything else is the same as in Specific Implementation Methods One to Two.

[0037] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the alkali is one of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, and potassium carbonate. Everything else is the same as in Specific Implementation Methods One to Three.

[0038] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the molar ratio of polyethylene glycol to epichlorohydrin is (1.0-3.0):1. Everything else is the same as in Specific Implementation Methods One to Four.

[0039] Specific Implementation Method Six: This implementation method differs from one of Specific Implementation Methods One to Five in that the molar ratio of polyethylene glycol to epichlorohydrin is (1.0-1.5):1. Everything else is the same as one of Specific Implementation Methods One to Four.

[0040] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that the molar ratio of the alkali to bisphenol A in step two is (1.0-5.0):1. Everything else is the same as in Specific Implementation Methods One to Six.

[0041] Specific Implementation Method Eight: This implementation method differs from one of Specific Implementation Methods One to Seven in that the molar ratio of the alkali to bisphenol A in step two is (2.0-2.3):1. Everything else is the same as in one of Specific Implementation Methods One to Six.

[0042] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the molar ratio of the alkali to epichlorohydrin in step three is (1.0-5.0):1. Everything else is the same as in Specific Implementation Methods One to Eight.

[0043] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that the molar ratio of alkali to epichlorohydrin in step three is (2.0-3.0):1. Everything else is the same as in Specific Implementation Methods One to Eight.

[0044] Specific Implementation Method Eleven: This implementation method differs from Specific Implementation Methods One through Ten in that the molar ratio of the unilaterally chlorinated polyethylene glycol to bisphenol A is (1.0-2.0):1. Everything else is the same as in Specific Implementation Methods One through Ten.

[0045] Specific Implementation Method Twelve: This implementation method differs from Specific Implementation Methods One to Eleven in that the molar ratio of the unilaterally chlorinated polyethylene glycol to bisphenol A is (1.0-1.5):1. Everything else is the same as in Specific Implementation Methods One to Eleven.

[0046] Specific Embodiment Thirteen: This embodiment differs from Specific Embodiments One to Twelve in that the molar ratio of bisphenol A to epichlorohydrin grafted onto one side of polyethylene glycol is 1:(1.0-6.0). Everything else is the same as in Specific Embodiments One to Twelve.

[0047] Specific Embodiment Fourteen: This embodiment differs from Specific Embodiments One to Twelve in that the molar ratio of bisphenol A to epichlorohydrin in polyethylene glycol grafted with one side of the hydroxyl group is 1:(4.0-6.0). Everything else is the same as in Specific Embodiments One to Twelve.

[0048] Specific Embodiment Fifteen: This embodiment differs from Specific Embodiments One to Fourteen in that the HLB value of the self-emulsifying epoxy resin is 14.47 (a self-emulsifying epoxy resin with polyethylene glycol 800 as the hydrophilic end). Everything else is the same as in Specific Embodiments One to Fourteen.

[0049] Specific Embodiment Sixteen: This embodiment differs from Specific Embodiments One to Fifteen in that the epoxy value of the self-emulsifying epoxy resin is 0.085 (a self-emulsifying epoxy resin with polyethylene glycol 800 as the hydrophilic end). Everything else is the same as in Specific Embodiments One to Fifteen.

[0050] The embodiments of the present invention will be described in detail below. The following embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0051] Example 1:

[0052] The method for preparing the self-emulsifying epoxy resin of this embodiment includes the following steps:

[0053] 5.00 g of polyethylene glycol 200 (PEG200) was added to 2.313 g of epichlorohydrin, followed by 0.091 ml of boron trifluoride tetrahydrofuran complex. The mixture was stirred at room temperature for 4 h to obtain mono-chlorinated polyethylene glycol 200. 5.70 g of bisphenol A was added to the mono-chlorinated polyethylene glycol 200. After the bisphenol A was completely dissolved, 0.3 mol / L sodium hydroxide solution was added, followed by 2.313 g of epichlorohydrin. Simultaneously, sodium hydroxide solution was slowly added dropwise. After the addition was complete, the reaction was carried out at 70 °C for 2 h. Heating was then stopped, and the reaction system was extracted multiple times. The organic layer solution was then rotary evaporated at 80 °C to obtain the product, a self-emulsifying epoxy resin grafted with hydrophilic PEG200 groups.

[0054] The prepared self-emulsifying epoxy resin aqueous solution grafted with hydrophilic PEG200 showed obvious demulsification after being left at room temperature for 60 days.

[0055] The product is a self-emulsifying epoxy resin with polyethylene glycol 200 as the hydrophilic end. Its 1H NMR spectrum is shown in the attached image. Figure 1 :

[0056] 1 H NMR(300MHz,Chloroform-d)δ7.21-7.07(m,4H),6.91-6.74(m,4H),4.29-3.87(m,7H),3.85-3.52(m,16H),3.35(d d,J=5.9,4.1,2.8Hz,1H),2.91(ddd,J=5.4,4.1,1.2Hz,1H),2.82-2.71(m,1H),2.06(s,1H),1.28(t,J=7.1Hz,1H).

[0057] Example 2: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that in step two, the amount of epichlorohydrin used is 4.0 equivalents of the amount of bisphenol A molecules grafted onto one side of polyethylene glycol 200. The resulting product is a self-emulsifying epoxy resin with the hydrophilic end of the grafted polyethylene glycol 200. A small portion of the system polymerizes, with a yield of 80%. The resulting product is a colorless, transparent, oily liquid.

[0058] Example 3: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that in step two, the amount of epichlorohydrin used is 5.0 equivalents of the amount of bisphenol A molecules grafted onto one side of polyethylene glycol 200. The resulting product is a self-emulsifying epoxy resin with a hydrophilic end grafted onto polyethylene glycol 200, a colorless, transparent, oily liquid, with a yield of 96%.

[0059] Example 4: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that in step two, the amount of epichlorohydrin used is 6.0 equivalents of the amount of bisphenol A molecules grafted onto one side of polyethylene glycol 200. The resulting product is a self-emulsifying epoxy resin with the hydrophilic end of the grafted polyethylene glycol 200, a colorless, transparent, oily liquid, with a yield of 95%.

[0060] Example 5: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that in step one, the amount of epichlorohydrin used is 1.0 equivalent of polyethylene glycol 200, and the resulting product is monochloroethylene glycol 200, a colorless, transparent, oily liquid with an epoxy value of 0.15 and a yield of 95%.

[0061] Example 6: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that in step one, the amount of epichlorohydrin used is 1.1 equivalents of polyethylene glycol 200. The resulting product is monochloroethylene glycol 200, a colorless, transparent, oily liquid with an epoxy value of 0.182 and a yield of 96%.

[0062] Example 7: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that in step one, the amount of epichlorohydrin used is 1.2 equivalents of polyethylene glycol 200. The resulting product is monochloroethylene glycol 200, a colorless, transparent, oily liquid with an epoxy value of 0.18 and a yield of 94%.

[0063] Example 8: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the reaction time of the unilaterally chlorinated polyethylene glycol 200 with bisphenol A in step two is increased to 2.5 hours. The resulting product is a self-emulsifying epoxy resin with the hydrophilic end of grafted polyethylene glycol 200, a colorless, transparent, oily liquid, with a yield of 95%.

[0064] Example 9: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the concentration of sodium hydroxide in step two is 0.2 mol / L. The resulting product is a self-emulsifying epoxy resin grafted with polyethylene glycol 200 as the hydrophilic end, a colorless, transparent, oily liquid with an epoxy value of 0.2.

[0065] Example 10: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the concentration of sodium hydroxide in step two is 0.3 mol / L. The resulting product is a self-emulsifying epoxy resin grafted with polyethylene glycol 200 as the hydrophilic end, a colorless, transparent, oily liquid with an epoxy value of 0.22.

[0066] Example 11: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the concentration of sodium hydroxide in step two is 0.4 mol / L. The resulting product is a self-emulsifying epoxy resin grafted with polyethylene glycol 200 as the hydrophilic end, a colorless, transparent, oily liquid with an epoxy value of 0.21.

[0067] Example 12: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the grafted hydrophilic group is PEG300, and the resulting product is a colorless, transparent, oily liquid with a yield of 95%.

[0068] The prepared self-emulsifying epoxy resin aqueous solution grafted with hydrophilic groups PEG300 showed slight demulsification after being left at room temperature for 60 days.

[0069] The product is a self-emulsifying epoxy resin with polyethylene glycol 300 as the hydrophilic end. Its 1H NMR spectrum is shown in the attached image. Figure 3 :

[0070] product 1 H NMR(300MHz,Chloroform-d)δ7.21-6.72(m,8H),4.23-4.04(m,3H),4.03-3.8 8(m,3H),3.82-3.50(m,24H),2.89(ddd,J=5.1,4.0,1.0Hz,2H),1.62(s,6H).

[0071] Example 13: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the grafted hydrophilic group is PEG400, and the resulting product is a colorless, transparent, oily liquid with a yield of 96%.

[0072] The prepared self-emulsifying epoxy resin aqueous solution grafted with hydrophilic groups PEG400 showed very slight demulsification after being left at room temperature for 60 days.

[0073] The product is a self-emulsifying epoxy resin with polyethylene glycol 400 as the hydrophilic end. Its 1H NMR spectrum is shown in the attached image. Figure 4 :

[0074] 1 H NMR(300MHz,Chloroform-d)δ7.19-7.08(m,4H),6.89-6.76(m,4H),4.24-4.07(m,4H),4.03-3.90(m,3H),3. 80m-3.55(m,29H),3.40-3.31(m,1H),2.91(dd,J=5.0,4.1Hz,1H),2.75(dd,J=5.0,2.7Hz,1H),1.64(s,6H).

[0075] Example 14: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the grafted hydrophilic group is PEG600, the reaction time is 2.4 h, and the resulting product is a colorless, transparent, oily liquid with a yield of 95%.

[0076] The prepared self-emulsifying epoxy resin aqueous solution grafted with hydrophilic PEG600 showed no demulsification after being left at room temperature for 60 days.

[0077] The product is a self-emulsifying epoxy resin with polyethylene glycol 600 as the hydrophilic end. Its 1H NMR spectrum is shown in the attached image. Figure 5 :

[0078] product 1 H NMR(300MHz,Chloroform-d)δ7.11(dd,J=9.0,2.8Hz,4H),6.80(dd,J=8.9,2.5Hz,4H),4.21-4.04(m,3H),4 .01-3.88(m,3H),3.75-3.52(m,43H),3.33(dd,J=6.4,2.9Hz,1H),2.73(dd,J=5.0,2.7Hz,1H),1.62(s,6H).

[0079] Example 15: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the grafted hydrophilic group is PEG800, and the resulting product is a colorless, transparent, oily liquid with a yield of 96%.

[0080] Example 16: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the grafted hydrophilic group is PEG800, the reaction temperature in step one is raised to 40°C, and the resulting product is a colorless, transparent, oily liquid with a yield of 96.5%.

[0081] Example 17: All experimental conditions and processing methods in this example are the same as in Example 1. The only difference is that the reaction time of the unilaterally chlorinated polyethylene glycol 800 with bisphenol A in step two is increased to 4.0 h. The resulting product is a self-emulsifying epoxy resin with the hydrophilic end of grafted polyethylene glycol 800, a colorless, transparent, oily liquid, with a yield of 97%.

[0082] The prepared self-emulsifying epoxy resin aqueous solution grafted with hydrophilic PEG800 showed no demulsification after being left at room temperature for 60 days.

[0083] The product is a self-emulsifying epoxy resin with polyethylene glycol 600 as the hydrophilic end. Its 1H NMR spectrum is shown in the attached image. Figure 4 :

[0084] 1H NMR(300MHz,Chloroform-d)δ7.11(dd,J=8.1,3.1Hz,4H),6.86-6.73(m,4H),4.25-4.05(m,2H),4.04-3.86(m,3H) ,3.78-3.53(m,56H),3.32(dd,J=5.8,4.1,3.0Hz,1H),2.88(dd,J=5.0,4.1Hz,1H),2.78-2.68(m,1H),1.62(s,6H).

[0085] For clarity, the results of the above embodiments are briefly summarized in Table 1 below. Table 1: Results of Embodiments:

[0086]

[0087] Table 1

[0088] As shown in Examples 1-17, the method of the present invention starts with inexpensive and readily available bisphenol A, uses inexpensive and environmentally friendly polyethylene glycol as the hydrophilic group and epichlorohydrin as the lipophilic group, and successfully synthesizes a high-epoxy-value self-emulsifying epoxy resin by changing the order of the grafting groups. Compared with the traditional method of directly grafting hydrophilic groups onto epoxy resin, this method avoids the destruction of epoxy groups, maximizes the preservation of epoxy value, and has a self-emulsifying effect, making it a novel, green, and universal synthesis method.

[0089] Preferred embodiments of the present invention have been described above. Modifications, variations, and substitutions to these preferred embodiments will be apparent to those skilled in the art upon reading this specification. The present invention can be practiced in ways other than those specifically described herein. Therefore, the present invention encompasses all such equivalent embodiments.

Claims

1. A method for producing a self-emulsifying epoxy resin, characterized by The structural general formula of the self-emulsifying epoxy resin is as follows: wherein n represents the polymerization degree of polyethylene glycol, and the polymerization degrees of the polyethylene glycols used in the method are respectively n=4, 6, 8, 12, and 16, i.e., polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 600, and polyethylene glycol 800. The preparation method of the self-emulsifying epoxy resin comprises the following steps: I. adding a catalyst into a mixed solution of polyethylene glycol and epichlorohydrin to prepare a single-side chlorinated polyethylene glycol; the polyethylene glycol is one of polyethylene glycol 200, polyethylene glycol 300, polyethylene glycol 400, polyethylene glycol 600 and polyethylene glycol 800; the catalyst is one of aluminum chloride, ferric chloride, zinc chloride, copper chloride and boron trifluoride tetrahydrofuran complex; the molar ratio of polyethylene glycol to epichlorohydrin is (1.0-3.0):1; II. adding bisphenol A into the single-side chlorinated polyethylene glycol solution to generate a bisphenol A derivative of polyethylene glycol grafted with a phenolic hydroxyl group on one side under the catalysis of an alkali; the molar ratio of the alkali to bisphenol A is (1.0-5.0):1; III. adding epichlorohydrin into the above system to graft an epoxy group on the other side of the phenolic hydroxyl group of bisphenol A under the action of an alkali to prepare a self-emulsifying epoxy resin; the alkali is one of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate and potassium carbonate, the concentration of the alkali solution is (0.2-1.0) mol / L, and the molar ratio of epichlorohydrin to the bisphenol A derivative grafted with a hydrophilic group on one side of the hydroxyl group is (1.0-6.0):1; The hydrophilic group is grafted first, and then the lipophilic group is grafted, so as to avoid the damage of the epoxy group; The reaction temperature for grafting the epoxy group on the other side of the phenolic hydroxyl group of bisphenol A in step III is 20-100℃.

Images