Waterborne epoxy ester resin composition and its preparation method

Abstract

This invention provides an aqueous epoxy ester resin composition and its preparation method. By grafting vinyl monomers onto an epoxy ester intermediate, and utilizing the higher reactivity of the conjugated double bonds in epoxy ester intermediate A, the grafting rate of the vinyl monomers onto the epoxy ester component is significantly increased, reducing the relative content of vinyl self-polymers and improving the water resistance and corrosion resistance of the coating. Simultaneously, through a two-step esterification method combined with a specific initiator and a specific reaction temperature range, the grafting rate of vinyl monomers and epoxy esters is increased while maintaining a suitable resin viscosity, thus not affecting the production and application of the aqueous epoxy ester resin composition. Furthermore, this invention utilizes the preferential grafting of vinyl polymer segments with the conjugated epoxy ester intermediate A, achieving a concentrated distribution of vinyl segments within the conjugated epoxy ester segments, significantly reducing the viscosity of the aqueous epoxy ester resin dispersion, thus facilitating the production and application of the aqueous epoxy ester resin composition.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, and in particular, relates to an aqueous epoxy ester resin composition and its preparation method. Background Technology

[0002] In recent years, with the increasing awareness of environmental protection, the use of waterborne epoxy ester resins and coatings to replace solvent-based coating systems has become a development trend in this sub-sector. Currently, the mainstream waterborne epoxy ester resins are typically obtained through vinyl modification to achieve self-emulsifying waterborne epoxy ester resins. The aforementioned method for preparing waterborne epoxy ester resins first involves esterification of epoxy resin and fatty acids to obtain an epoxy ester intermediate. Then, a graft copolymerization of the epoxy ester intermediate with a hydrophilic vinyl monomer (such as acrylic acid) is performed to obtain a water-dispersible vinyl-modified waterborne epoxy ester resin. During the graft modification process using vinyl monomers, a portion of the vinyl monomers grafts onto the fatty acid segments in the epoxy ester, forming a vinyl polymer-epoxy ester copolymer; a significant portion of the vinyl monomers undergoes self-polymerization, forming vinyl monomer self-polymers. Therefore, the waterborne epoxy ester resin prepared by existing technologies is actually a mixture, with main components including the vinyl polymer-epoxy ester copolymer, ungrafted epoxy ester polymer, and vinyl monomer self-polymers. Because of the low molecular weight of vinyl monomer self-polymers, the relative content of vinyl monomer self-polymers significantly affects the water resistance and corrosion resistance of waterborne epoxy ester resins.

[0003] Currently, an effective method to reduce the relative content of vinyl monomer self-polymers in waterborne epoxy ester resin compositions is to use fatty acids with a higher content of conjugated double bonds during the preparation of epoxy ester intermediates. However, in the later stages of epoxy ester preparation, conjugated fatty acids tend to self-polymerize during the high-temperature esterification stage (200–230°C), leading to a rapid increase in the viscosity of the waterborne epoxy ester resin, thus making the synthesis of epoxy ester intermediates difficult to control. Furthermore, during the copolymerization of vinyl monomers and epoxy ester intermediates, the conjugated fatty acid segments are highly reactive and prone to gelation. Summary of the Invention

[0004] The purpose of this invention is to provide an aqueous epoxy ester resin composition to solve the technical problems of insufficient copolymerization between vinyl monomers and epoxy ester intermediates in existing aqueous epoxy ester resin compositions, resulting in a high content of vinyl monomer self-polymers, and uniform distribution of vinyl segments in epoxy ester segments, resulting in a high viscosity of the aqueous epoxy ester resin dispersion, which is detrimental to subsequent construction.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A waterborne epoxy ester resin composition is provided, wherein the raw material composition, based on a 100% percentage of the total mass of the raw materials, comprises 14.77–66.25% of a mixed monomer component, 5–20% of epoxy ester intermediate A, 45–60% of epoxy ester intermediate B, and 1.5–8% of a neutralizing agent H. The mixed monomer component comprises a first component and a second component, wherein the first component comprises the following components in the following percentages:

[0006] Hydrophilic vinyl monomer C 2-5%;

[0007] Non-hydrophilic vinyl monomer D 12-50%;

[0008] Initiator E 0.05–1.05%;

[0009] The second component comprises the following components in the following percentages:

[0010] Initiator F 0.02–0.2%;

[0011] Solvent G: 0.7%–10%.

[0012] Optionally, the preparation steps of the epoxy ester intermediate A include: adding 22.33 g of fatty acid I, 66.9 g of epoxy resin J, 0.09 g of polymerization inhibitor K and 0.88 g of catalyst L to a reactor equipped with a stirrer and a thermometer; stirring and heating to 135-145°C under nitrogen protection to carry out a ring-opening esterification reaction; maintaining the temperature for 5 hours; lowering the reaction temperature to 90-95°C; and adding 37.8 g of solvent M to obtain epoxy ester intermediate A.

[0013] Optionally, the fatty acid I is at least one of tung oil acid and dehydrated ricinoleic acid, the polymerization inhibitor K is at least one of 2,6-di-tert-butyl-p-cresol and hydroquinone, the catalyst L is triphenylphosphine, and the solvent M is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0014] Optionally, the epoxy resin J is a bisphenol A type epoxy resin, and the epoxy value of the bisphenol A type epoxy resin is 0.09 to 0.14 mol / 100g.

[0015] Optionally, the preparation steps of the epoxy ester intermediate B include: adding fatty acid N, epoxy resin O, catalyst P, and dehydrating solvent Q into a reaction vessel equipped with a water separator, slowly raising the temperature to 100-130°C, holding at this temperature for 1 hour to melt the epoxy resin O, and simultaneously starting stirring. The temperature is gradually increased to 200-230°C at a rate of 20°C / hour, held at this temperature for 5 hours, then cooled to 160-180°C, removing the dehydrating solvent Q under vacuum, cooling to 90-100°C, and adding diluent R while stirring to obtain epoxy ester intermediate B.

[0016] Optionally, the fatty acid N is at least one of oleic acid, linoleic acid, linolenic acid, and soybean oil; the catalyst P is at least one of triphenylphosphine, dibutyltin dilaurate, and monobutyltin oxide; the dehydrating solvent Q is at least one of pseudotrimethylbenzene, mesitylene, C9 aromatics, methyl isobutyl ketone, and solvent oil D40; and the diluting solvent R is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0017] Optionally, the epoxy resin O is a bisphenol A type epoxy resin, and the epoxy value of the bisphenol A type epoxy resin is 0.04 to 0.22 mol / 100g.

[0018] Optionally, the hydrophilic vinyl monomer C includes at least one of acrylic acid and methacrylic acid, and the non-hydrophilic vinyl monomer D is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, isobornyl methacrylate, benzyl acrylate, and styrene.

[0019] Another objective of this invention is to provide a method for preparing an aqueous epoxy ester resin composition.

[0020] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for preparing an aqueous epoxy ester resin composition capable of preparing any of the aqueous epoxy ester resin compositions provided by the above solutions, wherein the method for preparing the aqueous epoxy ester resin composition includes the following steps:

[0021] Step S01: Weigh each raw material according to the components contained in the aqueous epoxy ester resin composition according to any one of claims 1 to 8;

[0022] Step S02: Mix epoxy ester intermediate A and epoxy ester intermediate B, and stir until homogeneous to obtain epoxy ester intermediate mixture.

[0023] Step S03: Heat the epoxy ester intermediate mixture to 110-140°C, and add the mixed monomer component dropwise to the epoxy ester intermediate mixture;

[0024] Step S04: After the addition is complete, the epoxy ester intermediate mixture containing the added monomer components is kept at 130-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare the waterborne epoxy ester resin composition.

[0025] Optionally, in step S03, the mixed monomer component includes a first component and a second component. During the process of adding the mixed monomer component to the epoxy ester intermediate mixed component, the first component is added dropwise over 3 to 4 hours, and then the temperature of the epoxy ester intermediate mixed component is adjusted to 130 to 150°C, and the second component is added dropwise over 1 to 2 hours.

[0026] Compared with the prior art, one or more technical solutions in the embodiments of the present invention have at least one of the following beneficial effects:

[0027] In the aqueous epoxy ester resin compositions of the embodiments of the present invention, or the aqueous epoxy ester resin compositions prepared by the preparation methods of the embodiments of the present invention, during the graft copolymerization of vinyl monomers with epoxy ester intermediates, the vinyl monomers preferentially graft copolymerize with conjugated epoxy ester intermediate A. This results in the vinyl monomers not exhibiting a uniform distribution in the conjugated epoxy ester intermediate A and the non-conjugated epoxy ester intermediate B as in conventional graft polymerization. Consequently, the corresponding hydrophilic vinyl segments are preferentially grafted into the segments of conjugated epoxy ester intermediate A. Thus, the non-uniform distribution of hydrophilic vinyl segments significantly improves the efficiency of the hydrophilic groups, resulting in a significant reduction in the viscosity of the aqueous epoxy ester resin composition during water dispersion, facilitating the production and application of the aqueous epoxy ester resin composition.

[0028] The method for preparing the aqueous epoxy ester resin composition in this invention involves a ring-opening esterification reaction between a fatty acid with a high content of conjugated double bonds and an epoxy resin A with a specific molecular weight range at 130–150°C, yielding an epoxy ester intermediate A with a high content of conjugated double bonds. A high-temperature esterification and dehydration reaction is then carried out between a fatty acid with a high content of non-conjugated double bonds and an epoxy resin B with a specific molecular weight range at 130–230°C, yielding an epoxy ester intermediate B with a high content of non-conjugated fatty acids. This method ensures a high total fatty acid content in the prepared aqueous epoxy ester resin composition while simultaneously achieving a specific proportion of conjugated fatty acids in the composition and maintaining stable viscosity during resin synthesis. Furthermore, the introduction of fatty acids with a high content of conjugated double bonds during the preparation of the epoxy ester intermediate avoids their participation in the high-temperature esterification reaction, overcoming the technical challenge of high viscosity and easy gelation during the preparation of epoxy ester intermediates based on conjugated fatty acids. Furthermore, during the graft copolymerization of vinyl monomers and epoxy ester intermediates, the characteristic that the conjugated double bonds in epoxy ester intermediate A are more easily copolymerized with vinyl monomers is utilized to increase the grafting rate of vinyl monomers and epoxy ester intermediates. This increases the gel content of the waterborne epoxy ester composition under the action of a drying agent to over 65%, significantly reduces the relative content of vinyl monomer self-polymers, and maintains the waterborne epoxy ester resin at a relatively low product viscosity to ensure good workability of the resin product. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0030] This invention provides an aqueous epoxy ester resin composition. The raw material composition, based on 100% of the total mass of the raw materials, comprises 14.77–66.25% of a mixed monomer component, 5–20% of epoxy ester intermediate A, 45–60% of epoxy ester intermediate B, and 1.5–8% of a neutralizing agent H. The mixed monomer component includes a first component and a second component. The first component comprises the following components in the following percentages:

[0031] Hydrophilic vinyl monomer C 2-5%;

[0032] Non-hydrophilic vinyl monomer D 12-50%;

[0033] Initiator E 0.05–1.05%;

[0034] The second component comprises the following components in the following percentages:

[0035] Initiator F 0.02–0.2%;

[0036] Solvent G: 0.7%–10%.

[0037] It should be noted that, in some embodiments, epoxy ester intermediate A is prepared by a ring-opening esterification reaction of epoxy resin J and fatty acid I. The raw materials for preparing epoxy ester intermediate A include fatty acid I, epoxy resin J, polymerization inhibitor K, catalyst L, and solvent M. The preparation steps of epoxy ester intermediate A include: adding 22.33 g of fatty acid I, 66.9 g of epoxy resin J, 0.09 g of polymerization inhibitor K, and 0.88 g of catalyst L to a reactor equipped with a stirrer and a thermometer; stirring and heating to 135–145 °C under nitrogen protection for a ring-opening esterification reaction; maintaining the temperature for 5 hours; lowering the reaction temperature to 90–95 °C; and adding 37.8 g of solvent M to obtain epoxy ester intermediate A.

[0038] It should be noted that in some embodiments, the polymerization inhibitor K is at least one of 2,6-di-tert-butyl-p-cresol and hydroquinone, the catalyst L is triphenylphosphine, and the solvent M is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0039] It should be noted that, in some embodiments, the amount of each component is expressed as a percentage of the total mass of all polymer raw materials in epoxy ester intermediate A. The relative molar ratio of fatty acid I to epoxy resin J is (1.9–2.1):1, and their total mass accounts for 65–75% of the total mass of epoxy ester intermediate A. The polymerization inhibitor K accounts for 0.02–0.09% of the total mass of epoxy ester intermediate A, the catalyst L accounts for 0.28–0.9% of the total mass of epoxy ester intermediate A, and the solvent M accounts for 28–32% of the total mass of epoxy ester intermediate A.

[0040] It should be noted that in some of the embodiments, fatty acid I is at least one of tung oil acid and dehydrated ricinoleic acid, polymerization inhibitor K is at least one of 2,6-di-tert-butyl-p-cresol and hydroquinone, catalyst L is triphenylphosphine, and solvent M is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0041] It should be noted that in some embodiments, epoxy resin J is bisphenol A type epoxy resin, and the epoxy value of bisphenol A type epoxy resin is 0.09 to 0.14 mol / 100g.

[0042] It should be noted that, in some embodiments, epoxy ester intermediate B is prepared from fatty acid N and epoxy resin O through ring-opening and esterification reactions. The raw materials for preparing epoxy ester intermediate B include fatty acid N, epoxy resin O, catalyst P, dehydrating solvent Q, and diluent R. The preparation steps of epoxy ester intermediate B include: adding fatty acid N, epoxy resin O, catalyst P, and dehydrating solvent Q into a reaction vessel equipped with a water separator; slowly raising the temperature to 100-130°C; maintaining this temperature for 1 hour to melt the epoxy resin O; simultaneously starting stirring; gradually raising the temperature to 200-230°C at a rate of 20°C / hour; maintaining this temperature for 5 hours; then cooling to 160-180°C; removing the dehydrating solvent Q under vacuum; cooling to 90-100°C; and adding the diluent R while stirring to obtain epoxy ester intermediate B.

[0043] It should be noted that, in some embodiments, fatty acid N is at least one of oleic acid, linoleic acid, linolenic acid, and soybean oil; catalyst P is at least one of triphenylphosphine, dibutyltin dilaurate, and monobutyltin oxide; dehydrating solvent Q is at least one of pseudotrimethylbenzene, mesitylene, C9 aromatics, methyl isobutyl ketone, and solvent oil D40; and diluent R is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0044] It should be noted that in some embodiments, the mass ratio of fatty acid N to epoxy resin O is (60-122):100, the catalyst P accounts for 0.1-3% of the total mass of fatty acid N and epoxy resin O, the dehydrating solvent Q accounts for 2-10% of the total mass of fatty acid N and epoxy resin O, and the diluting solvent R accounts for 30-55% of the total mass of fatty acid N and epoxy resin O.

[0045] It should be noted that in some embodiments, epoxy resin O is bisphenol A type epoxy resin, and the epoxy value of bisphenol A type epoxy resin is 0.04 to 0.22 mol / 100g.

[0046] It should be noted that, in some embodiments, the hydrophilic vinyl monomer C includes at least one of acrylic acid and methacrylic acid, and the non-hydrophilic vinyl monomer D is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, isobornyl methacrylate, benzyl acrylate, and styrene.

[0047] It should be noted that, in some embodiments, initiator E is at least one selected from tert-amyl peroxide-2-ethylhexanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide acetate, 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane, 1,1-di-tert-butylperoxidecyclohexane, and 2,2-di(tert-butylperoxide)butane, and initiator F is at least one selected from di-tert-butyl peroxide and di-tert-amyl peroxide. The solvent G is at least one selected from ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

[0048] This invention also provides a method for preparing the aqueous epoxy ester resin composition described in the above embodiments. In some embodiments, the method for preparing the aqueous epoxy ester resin composition provided by this invention includes the following steps:

[0049] Step S01: Weigh each raw material according to the components contained in the aqueous epoxy ester resin composition in any of the above embodiments;

[0050] Step S02: Mix epoxy ester intermediate A and epoxy ester intermediate B, and stir until homogeneous to obtain epoxy ester intermediate mixture.

[0051] Step S03: Heat the epoxy ester intermediate mixture to 110-140°C and add the mixed monomer component dropwise to the epoxy ester intermediate mixture;

[0052] Step S04: After the addition is complete, the epoxy ester intermediate mixture containing the mixed monomer components is kept at 130-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare the waterborne epoxy ester resin composition.

[0053] It should be noted that in step S03, the mixed monomer components include a first component and a second component. During the process of adding the mixed monomer components to the epoxy ester intermediate mixed components, the first component is added dropwise over 3 to 4 hours. Then, the temperature of the epoxy ester intermediate mixed components is adjusted to 130 to 150°C, and the second component is added dropwise over 1 to 2 hours.

[0054] The method for preparing an aqueous epoxy ester resin composition provided in this invention involves grafting vinyl monomers onto an epoxy ester intermediate. Utilizing the higher reactivity of the conjugated double bonds in epoxy ester intermediate A, the grafting rate of the vinyl monomers onto the epoxy ester component is significantly increased, reducing the relative content of vinyl self-polymers and improving the water resistance and corrosion resistance of the coating. Simultaneously, by employing a two-step esterification method combined with specific initiators and a specific reaction temperature range, the grafting rate of vinyl monomers and epoxy esters is increased while maintaining a suitable resin viscosity, thus not affecting the production and application of the aqueous epoxy ester resin composition. Furthermore, this invention utilizes the preferential grafting of vinyl polymer segments with the conjugated epoxy ester intermediate A, achieving a concentrated distribution of vinyl segments within the conjugated epoxy ester segments, significantly reducing the viscosity of the aqueous epoxy ester resin dispersion and facilitating the production and application of the aqueous epoxy ester resin composition. In addition, the entire process of preparing the waterborne epoxy ester resin composition is free of benzene compounds. During the epoxy esterification process, a solvent that meets the requirements for benzene compounds is used as a dehydration solvent. In the graft copolymerization, an initiator whose decomposition products do not contain benzene compounds is used to ensure that the final resin product is free of benzene compounds.

[0055] The method for preparing the waterborne epoxy ester resin composition provided in this invention innovatively designs the initiator and polymerization temperature during the grafting of vinyl monomers with epoxy ester intermediates. During graft copolymerization, a peroxide initiator whose decomposition products do not contain benzene compounds is selected, with a 0.1-hour half-life temperature in the range of 110–140°C. By using a specific initiator and a specific reaction temperature range (110–140°C), and later in the graft polymerization stage, a peroxide initiator whose decomposition products do not contain benzene compounds is selected, with a 0.1-hour half-life temperature in the range of 150–165°C. By using a specific initiator and a specific reaction temperature range (150–165°C), a good conversion rate of the remaining ungrafted monomers can be ensured, with the final monomer conversion rate reaching over 99.5%. This significantly reduces the relative content of vinyl monomer self-polymers and improves the initial water resistance and corrosion resistance of the coating. Meanwhile, since the active sites of fatty acids participating in the reaction are relatively reduced in the later stages of copolymerization, high-temperature polymerization will not significantly increase the resin viscosity while ensuring a high conversion rate, thus ensuring good workability of waterborne epoxy ester resin products.

[0056] The method for preparing an aqueous epoxy ester resin composition provided in this invention employs a two-step esterification process to introduce two types of fatty acids with different conjugated double bond contents. First, a fatty acid with a higher conjugated double bond content is designed to undergo a ring-opening esterification reaction with an epoxy resin A (epoxy value 0.09–0.14 mol / 100g) with a specific molecular weight range at 130–150°C, yielding an epoxy ester intermediate A with a high conjugated double bond content. Second, a fatty acid with a higher non-conjugated double bond content is designed to undergo a high-temperature esterification and dehydration reaction with an epoxy resin B with a specific molecular weight range at 130–230°C, yielding an epoxy ester intermediate B with a higher non-conjugated fatty acid content. This invention, while ensuring a high total fatty acid content in the prepared aqueous epoxy ester resin composition, simultaneously achieves a specific proportion of conjugated fatty acids in the aqueous epoxy ester composition and maintains stable viscosity during resin synthesis. In the preparation of epoxy ester intermediates, by introducing fatty acids with high conjugated double bond content, the high viscosity and easy gelation of these fatty acids during the high-temperature esterification reaction are avoided.

[0057] To enable those skilled in the art to clearly understand the above-described implementation details and operations of the present invention, and to demonstrate the significant improvement in performance of the waterborne epoxy ester resin composition and its preparation method, the following examples illustrate the implementation of the present invention.

[0058] The raw materials involved in the examples and comparative examples include:

[0059] NPES-901 epoxy resin, NPES-904 epoxy resin, NPES-907 epoxy resin, industrial grade, Nanya Electronic Materials (Kunshan) Co., Ltd.; Ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, industrial grade, Nanjing Gutian Chemical Co., Ltd.; Ethylene glycol tert-butyl ether, industrial grade, Maruzen, Japan; Pseudotrimethylbenzene, mesitylene, chemically pure, Shanghai Aladdin Biochemical Technology Co., Ltd.; Monobutyltin oxide, industrial grade, Shanghai Titan Technology Co., Ltd.; 2,6-di-tert-butyl-p-cresol, ultrapure grade, Shanghai Aladdin Biochemical Technology Co., Ltd.; Triphenylphosphine, industrial grade, Shanghai Lingfeng Chemical Reagent Co., Ltd.; Oleic acid, linoleic acid, linolenic acid, chemically pure, Shanghai Maclean Biochemical Technology Co., Ltd.; Tung oil acid, dehydrated castor oil Oleic acid, soybean oil acid, acrylic acid, methacrylic acid, styrene, butyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl acrylate, industrial grade, CNOOC Changzhou Environmental Coatings Co., Ltd.; Di-tert-amyl peroxide (DTAP), di-tert-butyl peroxide (DTBP), 1,1-di-tert-butylperoxide-3,3,5-trimethylcyclohexane (TMCH), industrial grade, AkzoNobel; Tert-amyl peroxide-2-ethylhexanoate (TAPO), industrial grade, Shandong Haijing New Materials Co., Ltd.; N,N-dimethylethanolamine (DMEA), industrial grade, Eastman Chemical Company, USA; AMP-95, industrial grade, Dow Chemical Company, USA; High-efficiency composite drying agent TY-CQ-88WD, industrial grade, Shanghai Taoyuan Cobalt Industry Co., Ltd.; 490, industrial grade, Minling (Germany); BYK-022, BYK-346, industrial grade, BYK (BYK Corporation); Carbon black, industrial grade, Degussa; Titanium dioxide R-902+, industrial grade, Chemours (USA); Precipitated barium sulfate, industrial grade, Nanfeng Group; Nubirox 106, industrial grade, Nubirox (Nubirox). ViscoPlus 3030, industrial grade, DIGIC; Unless otherwise stated, all raw materials used in the examples and comparative examples are commercially available products.

[0060] Example 1

[0061] Preparation of epoxy ester intermediate A1: In a reactor equipped with a stirrer and a thermometer, 22.33 g of tung oil acid, 66.9 g of NPES-904 epoxy resin, 0.09 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 0.88 g of catalyst triphenylphosphine were added. Under nitrogen protection, the mixture was stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature was lowered to 90℃, and 45 g of ethylene glycol tert-butyl ether was added to obtain epoxy ester intermediate A1.

[0062] Example 2

[0063] Preparation of epoxy ester intermediate A2: In a reactor equipped with a stirrer and thermometer, 22.33 g of dehydrated castor oil acid, 66.90 g of NPES-904 epoxy resin, 0.09 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 0.88 g of catalyst triphenylphosphine were added. Under nitrogen protection, the mixture was stirred and heated to 140±5℃ for ring-opening esterification reaction. After holding at this temperature for 5 hours, the reaction temperature was lowered to 90℃, and 45 g of ethylene glycol butyl ether was added to obtain epoxy ester intermediate A2.

[0064] Example 3

[0065] Preparation of epoxy ester intermediate B1: 1171.83 g of soybean oil acid, 156.27 g of NPES-901 epoxy resin, 3.28 g of triphenylphosphine, and 16.41 g of pseudotrimethylbenzene were added to a reaction vessel equipped with a water separator. The temperature was slowly increased to 100–130 °C and held at this temperature for 1 hour to melt the epoxy resin. Stirring was started, and the temperature was gradually increased to 210 °C at a rate of 20 °C / hour. After holding at 210 ± 5 °C for 5 hours, the temperature was lowered to 160–180 °C, and pseudotrimethylbenzene was removed by vacuum. The temperature was then lowered to 90–100 °C, and 140.62 g of ethylene glycol tert-butyl ether was added while stirring to obtain epoxy ester intermediate B1.

[0066] Example 4

[0067] Preparation of epoxy ester intermediate B2: 69.7 g of oleic acid, 140.1 g of linoleic acid, 139.41 g of NPES-901 epoxy resin, 34.85 g of NPES-907 epoxy resin, 7.68 g of triphenylphosphine, and 19.20 g of mesitylene were added to a reaction vessel equipped with a water separator. The temperature was slowly increased to 100–130 °C and held at this temperature for 1 hour to melt the epoxy resin. Stirring was started, and the temperature was gradually increased to 220 °C at a rate of 20 °C / hour. After holding at 220 ± 5 °C for 5 hours, the temperature was lowered to 160–180 °C, and the mesitylene was removed by vacuum. The temperature was then lowered to 90–100 °C, and 69.70 g of ethylene glycol butyl ether and 58.55 g of ethylene glycol tert-butyl ether were added while stirring to obtain epoxy ester intermediate B2.

[0068] Example 5

[0069] Preparation of epoxy ester intermediate B3: 175.84 g of linolenic acid, 100.92 g of NPES-904 epoxy resin, 43.24 g of NPES-907 epoxy resin, 9.6 g of monobutyltin oxide, and 25.6 g of methyl isobutyl ketone were added to a reaction vessel equipped with a water separator. The temperature was slowly increased to 100–130 °C and held at this temperature for 1 hour to melt the epoxy resin. Stirring was started, and the temperature was gradually increased to 220 °C at a rate of 20 °C / hour. After holding at 220 ± 5 °C for 5 hours, the temperature was lowered to 160–180 °C, and methyl isobutyl ketone was removed by vacuum. The temperature was then lowered to 90–100 °C, and 92.73 g of propylene glycol butyl ether and 72.07 g of propylene glycol methyl ether were added while stirring to obtain epoxy ester intermediate B3.

[0070] Before resin synthesis, a mixed monomer component is prepared according to the formulation in Table 1. The mixed monomer component includes a first component and a second component. The first component includes a hydrophilic vinyl monomer C, a non-hydrophilic vinyl monomer D, and an initiator E. The second component includes an initiator F and a solvent G.

[0071] Example 6

[0072] The preparation method of waterborne epoxy ester resin composition a includes the following steps: According to the formulation in Table 1, 134 g of epoxy ester intermediate A1 and 466 g of epoxy ester intermediate B1 are mixed and stirred evenly. The mixture is then heated to 115-125°C, and the first component of the mixed monomer components is added dropwise over 3-4 hours. Then, the temperature is adjusted to 135-140°C, and the second component of the mixed monomer components is added dropwise over 1-2 hours. After the addition is completed, the mixture is kept at 135-140°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare waterborne epoxy ester resin composition a.

[0073] Example 7

[0074] The preparation method of waterborne epoxy ester resin composition b includes the following steps: According to the formulation in Table 1, 200 g of epoxy ester intermediate A2 and 484.0 g of epoxy ester intermediate B2 are mixed and stirred evenly. The mixture is then heated to 110-115°C, and the first component of the mixed monomer components is added dropwise. The dropwise addition is completed within 3-4 hours. Then, the temperature is adjusted to 140-145°C, and the second component of the mixed monomer components is added dropwise. The dropwise addition is completed within 1-2 hours. After the dropwise addition is completed, the mixture is kept at 140-145°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare waterborne epoxy ester resin composition b.

[0075] Example 8

[0076] The preparation method of waterborne epoxy ester resin composition c includes the following steps: According to the formulation in Table 1, 50 grams of epoxy ester intermediate A1 and 380 grams of epoxy ester intermediate B3 are mixed and stirred evenly. The mixture is then heated to 130-140°C, and the first component of the mixed monomer components is added dropwise. The dropwise addition is completed within 3-4 hours. Then, the temperature is adjusted to 130-135°C, and the second component of the mixed monomer components is added dropwise. The dropwise addition is completed within 1-2 hours. After the dropwise addition is completed, the mixture is kept at 130-135°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare waterborne epoxy ester resin composition c.

[0077] Example 9

[0078] The preparation method of the waterborne epoxy ester resin composition d includes the following steps: According to the formulation in Table 1, 80 grams of epoxy ester intermediate A2 and 600 grams of epoxy ester intermediate B2 are mixed and stirred evenly. The mixture is then heated to 110-120°C, and the first component of the mixed monomer components is added dropwise over 3-4 hours. Then, the temperature is adjusted to 140-150°C, and the second component of the mixed monomer components is added dropwise over 1-2 hours. After the addition is completed, the mixture is kept at 140-150°C for 1-2 hours, cooled to 90-100°C, and neutralizing agent H is added to prepare the waterborne epoxy ester resin composition d.

[0079] Example 10

[0080] The preparation method of the waterborne epoxy ester resin composition e includes the following steps: According to the formulation in Table 1, 165 g of epoxy ester intermediate A1 and 486 g of epoxy ester intermediate B3 are mixed and stirred evenly. The mixture is then heated to 125-130°C, and the first component of the mixed monomer components is added dropwise over 3-4 hours. Then, the temperature is adjusted to 130-135°C, and the second component of the mixed monomer components is added dropwise over 1-2 hours. After the addition is completed, the mixture is kept at 130-135°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare the waterborne epoxy ester resin composition e.

[0081] Example 11

[0082] The preparation method of the waterborne epoxy ester resin composition f includes the following steps: According to the formulation in Table 1, 115 g of epoxy ester intermediate A2 and 580 g of epoxy ester intermediate B2 are mixed and stirred evenly. The mixture is then heated to 135-140°C, and the first component of the mixed monomer components is added dropwise over 3-4 hours. Then, the temperature is adjusted to 145-150°C, and the second component of the mixed monomer components is added dropwise over 1-2 hours. After the addition is completed, the mixture is kept at 145-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare the waterborne epoxy ester resin composition f.

[0083] Table 1. Raw material composition and formulation of the waterborne epoxy ester resin compositions in Examples 7 to 11

[0084]

[0085] Comparative Example 1

[0086] Preparation of the waterborne epoxy ester resin composition g: According to the formulation in Table 2, 600 g of epoxy ester intermediate A1 was stirred evenly, and the temperature was raised to 115-125℃. The first component of the mixed monomers was then added dropwise, and the addition was completed within 3-4 hours. Then, the temperature was adjusted to 135-140℃, and the second component of the mixed monomers was added dropwise, and the addition was completed within 1-2 hours. After the addition was completed, the temperature was maintained at 135-140℃ for 1-2 hours, and then cooled to 90-100℃. During the dropwise addition of the mixed monomers, the resin viscosity was too high, causing gelation, and the reaction was stopped, thus failing to prepare the waterborne epoxy ester resin composition g.

[0087] Comparative Example 2

[0088] Preparation of waterborne epoxy ester resin composition g: According to the formulations in Table 2 and Table 1, 600 g of epoxy ester intermediate B1 was stirred evenly, and the temperature was raised to 115-125℃. The first component of the mixed monomer components was then added dropwise, and the addition was completed within 3-4 hours. Then, the temperature was adjusted to 135-140℃ and the second component of the mixed monomer components was added dropwise, and the addition was completed within 1-2 hours. After the addition was completed, the temperature was maintained at 135-140℃ for 1-2 hours, and then the temperature was lowered to 90-100℃. Neutralizing agent H was added to prepare waterborne epoxy ester resin composition h.

[0089] Comparative Example 3

[0090] Preparation of waterborne epoxy ester resin composition i: According to the formulation in Table 2, 600g of epoxy ester intermediate X was stirred evenly, and the temperature was raised to 115-125℃. The first component of the mixed monomer components was then added dropwise, and the addition was completed within 3-4 hours. Then, the temperature was adjusted to 135-140℃ and the second component of the mixed monomer components was added dropwise, and the addition was completed within 1-2 hours. After the addition was completed, the temperature was maintained at 135-140℃ for 1-2 hours, and then the temperature was lowered to 90-100℃. Neutralizing agent H was added to prepare waterborne epoxy ester resin composition a.

[0091] The preparation process of epoxy ester intermediate X is as follows: 22.33 g of tung oil acid, 171.83 g of soybean oil acid, 156.27 g of NPES-901 epoxy resin, 66.9 g of NPES-904 epoxy resin, 4.16 g of triphenylphosphine catalyst, 0.09 g of polymerization inhibitor 2,6-di-tert-butyl-p-cresol, and 16.41 g of pseudotrimethylbenzene are added to a reaction vessel equipped with a water separator, and the temperature is slowly increased to... The epoxy resin was melted at 100-130℃ and slowly increased to 100-130℃. The temperature was maintained for 1 hour, and stirring was started. The temperature was gradually increased to 220℃ at a rate of 20℃ / hour. After maintaining the temperature at 220±5℃ for 5 hours, the temperature was lowered to 160-180℃. The pseudotrimethylbenzene was removed by vacuuming, and the temperature was lowered to 90-100℃. While stirring, 178.42 g of ethylene glycol tert-butyl ether was added to prepare epoxy ester intermediate X.

[0092] Comparative Example 4

[0093] Preparation of waterborne epoxy ester resin composition j: According to the formulation in Table 2, 134 g of epoxy ester intermediate A1 and 466 g of epoxy ester intermediate B1 were mixed and stirred evenly. The mixture was then heated to 115-125°C, and the first component of the mixed monomer components was added dropwise over 3-4 hours. The temperature was then adjusted to 140-145°C, and the second component of the mixed monomer components was added dropwise over 1-2 hours. After the addition was completed, the mixture was kept at 135-140°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H was added to prepare waterborne epoxy ester resin composition j.

[0094] Table 2. Raw material composition and formulation of the waterborne epoxy ester resin compositions with initial water resistance in Comparative Examples 1 to 5.

[0095]

[0096] Comparative Example 5

[0097] Preparation of waterborne epoxy ester resin composition k: According to the formulation in Table 1, 134 g of epoxy ester intermediate A1 and 466 g of epoxy ester intermediate B1 were mixed and stirred evenly. The mixture was then heated to 115-125°C, and the first component of the mixed monomer components was added dropwise over 3-4 hours. Then, the temperature was adjusted to 135-140°C, and the second component of the mixed monomer components was added dropwise over 1-2 hours. After the addition was completed, the mixture was kept at 120-125°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H was added to prepare the waterborne epoxy ester resin composition k.

[0098] Using the aqueous epoxy ester resin compositions prepared in Examples 6-11 and Comparative Examples 2-5 above as film-forming resins, aqueous epoxy ester resin coatings were prepared. The formulations of the aqueous epoxy ester resin coatings are shown in Table 3, and the preparation process of the aqueous epoxy ester resin coatings is as follows:

[0099] (1) According to the formulation in Table 3, the film-forming resins (a, b, c, d, e, f in the examples and Ch, Ci, Cj, Ck in the comparative examples), drier (TY-CQ-88WD), and pH adjuster (N,N-dimethylethanolamine) of each waterborne epoxy ester resin composition are first stirred and mixed evenly at a stirring speed of 1000 rpm. Deionized water is added while stirring, and after stirring for 30 min, waterborne epoxy ester dispersion is obtained.

[0100] (2) Add the dispersant sequentially to the reaction vessel. Add 490), defoamer (BYK-022), leveling agent (BYK-346), carbon black, titanium dioxide R-902+, precipitated barium sulfate, Nubirox 106, and deionized water to a mixing tank, mix and stir for 40-60 minutes, then start grinding until the fineness is <30μm.

[0101] (3) Add the thickener while stirring. ViscoPlus 3030 was used to adjust the viscosity, and the material was filtered to obtain a waterborne epoxy ester resin coating. The coating was then filtered, discharged, and packaged. The waterborne epoxy ester resin coatings prepared according to the waterborne epoxy ester resin composition used are sequentially designated as Ca, Cb, Cc, Cd, Ce, and Cf.

[0102] Table 3 Formulations of Waterborne Epoxy Ester Coatings

[0103]

[0104] The prepared waterborne epoxy ester coating was diluted with water to an appropriate viscosity and sprayed onto a polished cold-rolled steel plate. The film thickness was controlled at 50–60 μm. After surface drying at room temperature, the sample was placed in an oven at 80±2℃ for 30 minutes and left at room temperature for 7 days. The coating properties were then tested according to national standard methods. In addition, the waterborne epoxy ester resins prepared in the above examples and comparative examples were characterized, and the rotational viscosity of the resin composition, the viscosity of the waterborne epoxy ester dispersion, the benzene content, the grafting rate, and the residual monomer content were tested. The coating's appearance, surface drying time, adhesion, water resistance, initial water resistance, and neutral salt spray resistance were the main tests.

[0105] Rotational viscosity: The rotational viscosity of the resin was tested using an NDJ-8S rotational viscometer.

[0106] Viscosity of waterborne epoxy ester dispersion: To test the workability and dispersibility of waterborne epoxy ester resin in coating preparation, a waterborne epoxy ester resin composition was weighed in the specified proportions, and deionized water was added while stirring to prepare a waterborne epoxy ester dispersion with a solid content of 45%. The rotational viscosity of the resin was then tested.

[0107] Gel content: The grafting rate of waterborne epoxy ester resin is characterized by gel content. The specific test method is as follows: Weigh the waterborne epoxy ester resin composition, add 5 wt% of TY-CQ-88WD drying agent (total resin mass), stir evenly, form a film on a tetrafluoroethylene plate, and after surface drying, bake at 80℃ for 2 hours. After standing at 25±2℃ for 7 days, collect the solid resin and weigh it, recording the mass as M0 grams. Perform Soxhlet extraction, dry the extracted sample and weigh it, recording the weight as M1. Gel content = (M0-M1) / M0×100%.

[0108] Residual monomer content: The residual monomer content was determined using an Agilent 8890 gas chromatograph.

[0109] Benzene series content: The benzene series content of waterborne epoxy ester resin samples was determined in accordance with GB / T 23990-2009.

[0110] Initial water resistance: After spraying the sample, dry it in a standard constant temperature and humidity room at 25±2℃ for 24 hours. After edge sealing, place the sample in deionized water in a constant temperature room at 25±2℃, with about 2 / 3 of the sample immersed in water. Observe the coating condition every 2 hours within 24 hours, and observe it every 12 hours after 24 hours, until the coating blister, wrinkle or the substrate rusts. The initial water resistance is judged by the time it takes for the coating to be damaged.

[0111] Neutral salt spray resistance test: The corrosion resistance performance of the coating is determined by the neutral salt spray resistance test, in accordance with GB / T1771-2007. The test is conducted every 24 hours until the coating blisteres, rusts or peels off.

[0112] Other properties of the coating were tested in accordance with the relevant national standards, and the relevant test results are listed in Tables 4 and 5.

[0113] Table 4 shows the test results of the aqueous epoxy ester resin compositions in Examples 6 to 11 and Comparative Examples 1 to 5.

[0114]

[0115] Table 5 shows the test results of the performance of the waterborne epoxy ester coatings in Examples 7 to 11 and Comparative Examples 2 to 5.

[0116]

[0117] As can be seen from the data in Table 4, the rotational viscosity of the waterborne epoxy ester resin compositions prepared using the embodiments of the present invention is all below 50000 mPa·s, the dispersion viscosity is all below 1165 mPa·s, the gel content is all above 58%, and the residual monomer content is all below 0.9%.

[0118] As shown in Table 5, the aqueous epoxy ester resin composition prepared in the embodiments of this invention, used as the film-forming agent, produces aqueous epoxy ester resin coatings with excellent performance. Specifically, the coating has a smooth and even appearance, and the pencil hardness of the coating exceeds F, meeting the requirements of industrial coating primers. It is particularly noteworthy that, through polymer segment molecular design and process innovation, the aqueous epoxy ester resin coating prepared using the scheme of this invention achieves a neutral salt spray resistance time of 240 hours, demonstrating excellent corrosion resistance, and a water resistance of 240 hours, meeting the technical requirements for water resistance and corrosion resistance in the automotive parts industry.

[0119] Comparing Example 6 with Comparative Example 1, Comparative Example 1 used only epoxy ester intermediate A1 containing conjugated double bonds to prepare the waterborne epoxy ester. Due to the high reactivity of the conjugated double bonds, Comparative Example 1 gelled during the preparation of the waterborne epoxy ester resin due to its high viscosity, making it impossible to obtain the waterborne epoxy ester resin. Comparing Example 6 with Comparative Example 2, Comparative Example 2 used only epoxy ester intermediate B1 without conjugated double bonds. The viscosity of the waterborne epoxy ester composition h prepared in Comparative Example 2 decreased to 21675 mPa·s, but the corresponding rotational viscosity of the waterborne epoxy ester dispersion increased from 755 mPa·s in Example 6 to 3560 mPa·s in Comparative Example 2. This is obviously detrimental to the application of the waterborne epoxy ester resin composition. In addition, the gel content decreased from 65.91% in Example 7 to 43.17% in Comparative Example 2, and the residual monomer content increased to 1.48%. Furthermore, in Comparative Example 2, the initial water resistance of the corresponding coating of the waterborne epoxy ester resin composition h was reduced to 4h, and the neutral salt spray resistance time was reduced to 168h.

[0120] Comparing Example 6 with Comparative Example 3, Example 6 used a two-step esterification method to prepare epoxy ester intermediates A1 and B1, respectively, and used a mixture of epoxy ester intermediates A1 and B1 to prepare an aqueous epoxy ester resin composition a, which had a rotational viscosity of 34950 mPa·s. In contrast, Comparative Example 3 used a one-step esterification method to prepare epoxy ester intermediate X to synthesize an aqueous epoxy ester resin composition i. Although the preparation process, raw materials, and amounts were exactly the same in Example 6 and Comparative Example 3, the rotational viscosity of the aqueous epoxy ester resin composition i in Comparative Example 3 reached 104560 mPa·s, far exceeding the viscosity of the aqueous epoxy ester resin composition a in Example 6, which is unfavorable for the application of aqueous epoxy ester resins. Furthermore, the gel content of the aqueous epoxy ester resin composition i prepared in Comparative Example 3 was also reduced to below 60.48%, possibly due to the loss of conjugated double bonds during the high-temperature esterification process. Correspondingly, the initial water resistance of the waterborne epoxy ester coating corresponding to waterborne epoxy ester resin composition i in Comparative Example 3 was also reduced.

[0121] Comparing Example 6 with Comparative Example 4, the raw materials and processes of Example 6 and Example 7 are similar. The only difference is that the temperature during the copolymerization of vinyl monomers in Comparative Example 6 exceeds the range of "110-140℃" specified in the technical solution of this invention, and the reaction temperature is adjusted to "140-145℃". However, the viscosity of the waterborne epoxy ester resin composition j prepared in Comparative Example 4 increases to 89280 mPa.s, which is not conducive to product application and construction.

[0122] Comparing Example 6 with Comparative Example 5, the raw materials, formulation, and process of Comparative Example 5 and Example 6 were similar. The only difference was that the second component of the mixed monomer components was added and the holding temperature was adjusted from "140-150°C" to "120-125°C" during the copolymerization of vinyl monomers in Comparative Example 5. However, the gel content of the waterborne epoxy ester resin composition k prepared in Comparative Example 5 was slightly reduced to 63.81%, and the residual monomer content increased to 1.80%. Correspondingly, the initial water resistance of the coating of the waterborne epoxy ester resin composition k in Comparative Example 5 was also reduced to 16 hours.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waterborne epoxy ester resin composition, characterized in that, The raw material composition of the aqueous epoxy ester resin composition, based on 100% of the total mass of the raw materials, includes 14.77–66.25% of a mixed monomer component, 5–20% of epoxy ester intermediate A, 45–60% of epoxy ester intermediate B, and 1.5–8% of a neutralizing agent H. The mixed monomer component includes a first component and a second component, the first component comprising the following components in the following percentages: Hydrophilic vinyl monomers C2-5%; Non-hydrophilic vinyl monomers D12–50%; Initiator E 0.05–1.05%; The second component comprises the following components in the following percentages: Initiator F 0.02–0.2%; Solvent G 0.7-10%, The preparation steps of the epoxy ester intermediate A include: adding 22.33 g of fatty acid I, 66.9 g of epoxy resin J, 0.09 g of polymerization inhibitor K and 0.88 g of catalyst L to a reactor equipped with a stirrer and a thermometer; stirring and heating to 135-145°C under nitrogen protection to carry out a ring-opening esterification reaction; maintaining the temperature for 5 hours; lowering the reaction temperature to 90-95°C; and adding 37.8 g of solvent M to obtain epoxy ester intermediate A. The fatty acid I is at least one of tung oil acid and dehydrated ricinoleic acid; the epoxy resin J is a bisphenol A type epoxy resin; and the epoxy value of the bisphenol A type epoxy resin is 0.09-0.14 mol / 100g. The preparation steps of the epoxy ester intermediate B include: adding fatty acid N, epoxy resin O, catalyst P, and dehydrating solvent Q into a reaction vessel equipped with a water separator; slowly raising the temperature to 100-130°C; maintaining the temperature for 1 hour to melt the epoxy resin O; simultaneously starting stirring; gradually raising the temperature to 200-230°C at a rate of 20°C / hour; maintaining the temperature for 5 hours; lowering the temperature to 160-180°C; removing the dehydrating solvent Q under vacuum; lowering the temperature to 90-100°C; and adding diluent R while stirring to obtain epoxy ester intermediate B. The fatty acid N is at least one of oleic acid, linoleic acid, linolenic acid, and soybean oil acid; the epoxy resin O is a bisphenol A type epoxy resin; and the epoxy value of the bisphenol A type epoxy resin is 0.04-0.22 mol / 100g.

2. The aqueous epoxy ester resin composition according to claim 1, characterized in that, The polymerization inhibitor K is at least one of 2,6-di-tert-butyl-p-cresol and hydroquinone, the catalyst L is triphenylphosphine, and the solvent M is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

3. The aqueous epoxy ester resin composition according to claim 1, characterized in that, The catalyst P is at least one of triphenylphosphine, dibutyltin dilaurate, and monobutyltin oxide; the dehydrating solvent Q is at least one of pseudotrimethylbenzene, mesitylene, C9 aromatic hydrocarbon, methyl isobutyl ketone, and solvent oil D40; and the diluting solvent R is at least one of ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol tert-butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, and dipropylene glycol butyl ether.

4. The aqueous epoxy ester resin composition according to claim 1, characterized in that, The hydrophilic vinyl monomer C includes at least one of acrylic acid and methacrylic acid, and the non-hydrophilic vinyl monomer D is at least one of methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, isobornyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, isobornyl methacrylate, benzyl acrylate, and styrene.

5. A method for preparing an aqueous epoxy ester resin composition according to any one of claims 1 to 4, characterized in that, Includes the following steps: Step S01: Weigh each raw material according to the components contained in the aqueous epoxy ester resin composition according to any one of claims 1 to 4; Step S02: Mix epoxy ester intermediate A and epoxy ester intermediate B, and stir until homogeneous to obtain epoxy ester intermediate mixture. Step S03: Heat the epoxy ester intermediate mixture to 110-140°C, and add the mixed monomer component dropwise to the epoxy ester intermediate mixture; Step S04: After the addition is complete, the epoxy ester intermediate mixture containing the added monomer components is kept at 130-150°C for 1-2 hours, then cooled to 90-100°C, and neutralizing agent H is added to prepare the waterborne epoxy ester resin composition.

6. The method for preparing the aqueous epoxy ester resin composition according to claim 5, characterized in that, In step S03, the mixed monomer component includes a first component and a second component. During the process of adding the mixed monomer component to the epoxy ester intermediate mixed component, the first component is added dropwise over 3 to 4 hours. Then, the temperature of the epoxy ester intermediate mixed component is adjusted to 130 to 150°C, and the second component is added dropwise over 1 to 2 hours.

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