A bis-silane synergistic molecule pre-assembly in-situ grafting core-shell type epoxy resin emulsion and a preparation method thereof
Patent Information
- Application Number
- CN202611093479.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2026-05-12
- Filing Date
- 2026-07-22
- Publication Date
- 2026-09-25
AI Technical Summary
国内的产品多因VOC含量偏高、粒径较大、气味重、易破乳、成膜性能差等因素，使其应用受到限制，仅能应用于低端水性地坪涂料领域和建筑装饰漆领域，在水性工业漆等高端领域使用很少
1）本发明采用分子预组装-原位接枝-核壳乳化三步协同工艺，解决了传统硅基-丙烯酸改性环氧树脂乳液存在的相容性和稳定性差、工艺复杂等关键难题。通过双硅烷偶联剂改性与纳米硅溶胶协同增强，实现不同组份化学键合与性能协同，制备的乳液兼具优异的稳定性、成膜性与功能特性。
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Figure CN122810337A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polymer materials technology, and in particular to a bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion and its preparation method. Background Technology
[0002] Epoxy resins are widely used in various fields, such as coatings, adhesives, and composite materials, due to their excellent physicochemical properties. Traditional epoxy resin coatings are mostly solvent-based, releasing large amounts of organic solvents during application, which can seriously harm the health of construction workers and the environment. In recent years, waterborne epoxy resin emulsions have been widely used, even replacing oil-based epoxy resins in some areas. With increasing environmental awareness, waterborne epoxy coatings may eventually completely replace solvent-based epoxy coatings; however, developing high-performance, environmentally friendly waterborne epoxy resin emulsions is crucial.
[0003] Waterborne epoxy resin emulsions are crucial raw materials for waterborne industrial anti-corrosion coatings and waterborne adhesives. Their performance directly determines the technological development level of these fields in my country and is one of the technological bottlenecks restricting their development. Domestically produced products are limited in application due to factors such as high VOC content, large particle size, strong odor, easy demulsification, and poor film-forming properties. They are mainly used in low-end waterborne floor coatings and architectural decorative paints, and rarely in high-end fields such as waterborne industrial paints. Currently, there are generally four methods for preparing waterborne epoxy emulsions: mechanical method, phase inversion method, curing agent emulsification method, and chemical modification method. Among them, the mechanical method is simple and easy to implement, but due to problems such as large particle size, easy stratification, and poor stability of the prepared emulsion, such products are rarely seen on the market. The phase inversion method, curing agent emulsification method, and chemical modification method are the main methods for producing waterborne epoxy emulsions on the market. However, the first two methods result in poor water resistance and storage stability of the paint film due to the presence of emulsifiers in the system. The chemical modification method produces waterborne epoxy resin emulsions with small particle size and good stability. The absence of emulsifiers does not affect the paint film performance, but the operation is more complicated. Since the performance of waterborne epoxy resin emulsions plays a decisive role in the performance of waterborne epoxy coatings, it is necessary to develop a waterborne epoxy resin emulsion with good storage stability, safety and environmental protection, and good paint film performance. Summary of the Invention
[0004] Purpose of the invention: To overcome the shortcomings of the prior art, the purpose of this invention is to provide a bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion and its preparation method.
[0005] This invention employs a synergistic modification of epoxy resin using double-bond and amino-type silane coupling agents, simultaneously introducing bifunctional active sites. Through an integrated process, nano-silica sol is modified to achieve molecular-level precompatibility between the inorganic and organic phases. A composite seed emulsion is constructed using the epoxy-silica sol complex, overcoming the limitations of conventional monomer nucleation. Finally, the modified epoxy resin and acrylic monomer are synergistically grafted in situ and polymerized into a core-shell emulsion, successfully synthesizing a ternary interpenetrating core-shell emulsion in one step. The process steps of this invention are clear and highly controllable. The prepared emulsion exhibits good stability and a small particle size (D90=260nm), combining the weather resistance of inorganic silicon, the flexibility of acrylic acid, and the high adhesion of epoxy, making it widely applicable in coatings, adhesives, and other fields.
[0006] Technical solution: The method for preparing the dual-silane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion includes the following steps: (1) Heat and stir the epoxy resin, add silane coupling agent and catalyst with functional groups, and react at a constant temperature to obtain end-modified epoxy resin EP-Sca. (2) After hydrolyzing the silane coupling agent, it was added dropwise into the nano silica sol, the pH was adjusted, and the mixture was filtered to obtain the modified nano silica sol KH-SS; (3) Take deionized water, add emulsifier and stir to dissolve, add part of EP-Sca from step (1) and KH-SS from step (2), and disperse by ultrasonication to form a pre-emulsion; heat up and introduce nitrogen gas, add initiator and react at constant temperature to obtain seed emulsion; (4) The remaining EP-Sca and acrylic monomer mixture from step (1) is added dropwise to the seed emulsion. After the dropwise addition is complete, an initiator is added, and the temperature is raised to form a core-shell structure. After the reaction is complete, the temperature is lowered to adjust the pH, and the mixture is filtered to obtain the modified epoxy resin emulsion.
[0007] Further, the epoxy resin mentioned in step (1) is at least one of E-20, E-44 or E-51.
[0008] Further, the silane coupling agent with functional groups mentioned in step (1) is a compound of KH-570 and KH-550, or a compound of KH-570 and KH-792.
[0009] Furthermore, the nano-silica sol in step (2) has a particle size of 20-50 nm, a silica content of 20%-40%, and a modified nano-silica sol solid content of 10%-30%, preferably 20%-25%.
[0010] Further, the emulsifier in step (3) is at least one of sodium dodecyl sulfate, dodecylphenol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.
[0011] Furthermore, the emulsifier is a compound of sodium dodecyl sulfate and dodecylphenol polyoxyethylene ether, or a compound of sodium dodecyl sulfate and nonylphenol polyoxyethylene ether.
[0012] Furthermore, the initiator mentioned in steps (3) and (4) is at least one of benzoyl peroxide, potassium persulfate, and sodium bisulfite.
[0013] Further, the acrylic monomer mixture in step (4) is at least one of methyl methacrylate, butyl acrylate, acrylic acid, and ethyl acrylate; the added initiator accounts for 5% to 50% of the total mass of the initiator added in steps (3) and (4); the modified epoxy resin emulsion has a solid content of 35% to 45% and a viscosity of 400 to 1000 mPa·s at 25°C. A bissilane co-assembled molecular pre-assembled in situ grafted core-shell epoxy resin emulsion prepared by the method described above.
[0014] The molecular pre-assembly described in this invention refers to the formation of a molecularly homogeneous prepolymer by EP-Sca and KH-SS through hydrogen bonds and interactions between amino and silanol groups, providing a compatibility basis for subsequent in-situ grafting.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention employs a three-step synergistic process of molecular pre-assembly, in-situ grafting, and core-shell emulsification, solving key problems such as poor compatibility and stability, and complex processes inherent in traditional silicone-acrylic acid modified epoxy resin emulsions. Through modification with a bissilane coupling agent and synergistic enhancement with nano-silica sol, chemical bonding and performance synergy of different components are achieved, resulting in an emulsion with excellent stability, film-forming properties, and functional characteristics.
[0016] 2) This invention achieves molecular-level precompatibility of different components by pre-introducing polymerizable double bonds and amino active sites into epoxy resin, laying the foundation for in-situ grafting. It utilizes a synergistic process of seed emulsion polymerization and in-situ ring-opening grafting to achieve synchronous grafting of silicon-based segments, avoiding the problems of graft chain breakage and aggregation caused by traditional stepwise grafting.
[0017] 3) This invention constructs a core-shell emulsion with an epoxy resin-silicone core and an acrylic polymer shell (silicone-based acrylic-epoxy ternary interpenetrating core-shell emulsion). This method eliminates the need for segmented polymerization and multiple initiation processes, resulting in a simple process and controllable structure. By adjusting the emulsifier ratio and polymerization process, chemical bonding at the core-shell interface is achieved, improving the emulsion's storage stability and film-forming properties. Simultaneously, modified nano-silica sol is introduced as an auxiliary reinforcing phase, utilizing in-situ dispersion and chemical bonding to enhance the hardness and toughness of the cured film, addressing the drawback of traditional modified emulsions being hard and brittle. Attached Figure Description
[0018] Figure 1 The infrared spectrum of the modified epoxy emulsion in Example 1; Figure 2 This is a particle size distribution diagram of the modified epoxy emulsion in Example 1. Detailed Implementation
[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be further described below.
[0020] Example 1: The preparation steps of the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion in this embodiment are as follows: (1) Add 100g of E-44 epoxy resin to a 500mL three-necked flask, heat to 80℃, stir at 200r / min, add 8g of KH-570 and 4g of KH-792, and then add 0.5g of triethylamine as a catalyst. React at constant temperature for 2h to obtain modified epoxy resin (EP-Sca) with double bonds and amino groups at the end.
[0021] (2) Add 1g KH-550 to 10g anhydrous ethanol, slowly add 2-3 drops of 0.1mol / L hydrochloric acid, stir for 5 min to initiate hydrolysis, slowly add 5g deionized water, continue stirring to ensure complete hydrolysis, and obtain a hydrolyzed KH-550 ethanol solution. Add 50g of nano-silica sol to a three-necked flask, heat to 50℃, stir to disperse, slowly add the hydrolyzed KH-550 ethanol solution to the flask while stirring until all the solution is added (about 10 min), continue stirring until the dehydration condensation reaction is complete, adjust the pH to neutral, add 15g of deionized water, stir for 5 min, cool to room temperature and filter through a filter to obtain KH-550 modified nano-silica sol (KH-SS).
[0022] (3) Preparation of seed emulsion Add 200 mL of deionized water to another three-necked flask, add 3 g of SDS and 4.5 g of OP-10, stir to dissolve, then add 10 g of EP-Sca and 5 g of KH-SS, sonicate to disperse to form a pre-emulsion, heat to 70 °C, purge with nitrogen for protection, add 0.3 g of APS initiator, and react at a constant temperature for 30 min to obtain a milky white seed emulsion.
[0023] (4) In-situ grafting-core-shell emulsification polymerization The remaining EP-Sca and acrylic monomer mixture (MMA 36g, BA 18g, AA 6g) was slowly added dropwise to the seed emulsion at a dropping rate of 0.5mL / min, a temperature of 75℃, and a rotation speed of 250r / min. After the addition was complete, 0.2g of APS initiator was added, the temperature was raised to 80℃, and the reaction was maintained at this temperature for 3 hours. The temperature was then lowered to below 40℃, the pH was adjusted to neutral, and the mixture was stirred for 30 minutes before filtration to obtain the modified epoxy resin emulsion. Infrared spectroscopy characterization showed that the emulsion was 3450 cm⁻¹. -1 The values at 2925 and 2850 cm⁻¹ represent the hydroxyl absorption peaks on the surfaces of modified epoxy resin and silica sol. -1 The peaks are for the CH stretching vibrations of -CH2- and -CH3; 1724 cm⁻¹ -1 These are the C=O stretching vibration peaks of the ester group in modified epoxy resins and acrylic monomers; 1509, 1607 cm⁻¹. -1 It is the absorption peak of the benzene ring skeleton vibration in epoxy resin; 1460 cm⁻¹ -1 It is the CH bending vibration peak in -CH3 and -CH2-; 1246 cm⁻¹ -1 It is the stretching vibration of COC in the epoxy resin skeleton; 1116 cm -1 It is a Si-O-Si or Si-OC stretching vibration peak; 916 cm⁻¹ -1 This is the characteristic absorption peak of unreacted epoxy groups; 828 cm⁻¹ -1 The peak observed was an out-of-plane bending absorption peak of CH on the benzene ring of the epoxy resin, confirming the successful modification of the epoxy resin emulsion with silicone-based acrylic acid. Particle size analysis revealed that the emulsion particles were uniform and small (D90 = 260 nm).
[0024] Example 2: The preparation steps of the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion in this embodiment are as follows: (1) Add 100g of E-51 epoxy resin to a 500mL three-necked flask, heat to 80℃, stir at 200r / min, add 8g of KH-570 and 4g of KH-550, and then add 0.5g of triethylamine as a catalyst. React at constant temperature for 2h to obtain modified epoxy resin (EP-Sca) with double bonds and amino groups at the end.
[0025] (2) Add 1g KH-550 to 10g anhydrous ethanol, slowly add 2-3 drops of 0.1mol / L hydrochloric acid, stir for 5 min to initiate hydrolysis, slowly add 5g deionized water, continue stirring to ensure complete hydrolysis, and obtain a hydrolyzed KH-550 ethanol solution. Add 50g of nano-silica sol to a three-necked flask, heat to 50℃, stir to disperse, slowly add the hydrolyzed KH-550 ethanol solution to the flask while stirring until all the solution is added (about 10 min), continue stirring until the dehydration condensation reaction is complete, adjust the pH to neutral, add 15g of deionized water, stir for 5 min, cool to room temperature and filter through a filter to obtain KH-550 modified nano-silica sol (KH-SS).
[0026] (3) Preparation of seed emulsion Add 200 mL of deionized water to another three-necked flask, add 3 g of SDS and 4.5 g of NP-10, stir to dissolve, then add 10 g of EP-Sca and 5 g of KH-SS, sonicate to disperse and form a pre-emulsion, heat to 70 °C, purge with nitrogen for protection, add 0.3 g of BPO initiator, and react at a constant temperature for 30 min to obtain a milky white seed emulsion.
[0027] (4) In-situ grafting-core-shell emulsification polymerization The remaining EP-Sca and acrylic monomer mixture (MMA 36g, BA 18g, AA 6g) was slowly added dropwise to the seed emulsion at a rate of 0.5mL / min, a temperature of 75℃, and a rotation speed of 250r / min. After the addition was complete, 0.1g of BPO initiator was added, the temperature was raised to 80℃, and the reaction was carried out at a constant temperature for 3h. The temperature was then lowered to below 40℃, the pH was adjusted to neutral, and the mixture was stirred for 30min and filtered to obtain the modified epoxy resin emulsion.
[0028] Example 3: The preparation steps of the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion in this embodiment are as follows: (1) Add 100g of E-44 and E20 (mass ratio 9:1) epoxy resin to a 500mL three-necked flask, heat to 80℃, stir at 200r / min, add 8g of KH-570 and 4g of KH-792, and then add 0.5g of triethylamine as a catalyst. React at constant temperature for 2h to obtain modified epoxy resin (EP-Sca) with double bonds and amino groups at the end.
[0029] (2) Add 1g KH-550 to 10g anhydrous ethanol, slowly add 2-3 drops of 0.1mol / L hydrochloric acid, stir for 5 min to initiate hydrolysis, slowly add 5g deionized water, continue stirring to ensure complete hydrolysis, and obtain a hydrolyzed KH-550 ethanol solution. Add 50g of nano-silica sol to a three-necked flask, heat to 50℃, stir to disperse, slowly add the hydrolyzed KH-550 ethanol solution to the flask while stirring until all the solution is added (about 10 min), continue stirring until the dehydration condensation reaction is complete, adjust the pH to neutral, add 15g of deionized water, stir for 5 min, cool to room temperature and filter through a filter to obtain KH-550 modified nano-silica sol (KH-SS).
[0030] (3) Preparation of seed emulsion Add 200 mL of deionized water to another three-necked flask, add 3 g of SDS and 4.5 g of OP-10, stir to dissolve, then add 10 g of EP-Sca and 5 g of KH-SS, sonicate to disperse to form a pre-emulsion, heat to 70 °C, purge with nitrogen for protection, add 0.3 g of APS initiator, and react at a constant temperature for 30 min to obtain a milky white seed emulsion.
[0031] (4) In-situ grafting-core-shell emulsification polymerization The remaining EP-Sca and acrylic monomer mixture (MMA 36g, BA 18g, AA 6g) was slowly added dropwise to the seed emulsion at a dropping rate of 0.5mL / min, a temperature of 75℃, and a rotation speed of 250r / min. After the addition was complete, 0.1g of APS initiator was added, the temperature was raised to 80℃, and the reaction was carried out at a constant temperature for 3h. The temperature was then lowered to below 40℃, the pH was adjusted to neutral, and the mixture was stirred for 30min and filtered to obtain the modified epoxy resin emulsion.
[0032] Comparative Example 1 (no molecular pre-assembly, no core-shell structure) The preparation steps of the aqueous epoxy resin emulsion in this embodiment are as follows: (1) 100g of E-44 epoxy resin was stirred at 80℃ and 200r / min, and 8g of KH-570 and 0.5g of triethylamine were added. The mixture was reacted at a constant temperature for 2h to obtain monosilane modified epoxy resin (EP-KH).
[0033] (2) Add 200 mL of deionized water, 3 g of SDS and 4.5 g of OP-10 to a three-necked flask, dissolve them, add acrylic monomer mixture (MMA 36 g, BA 18 g, AA 6 g), stir for 30 min, add 0.5 g of APS at 70 °C, polymerize for 3 h to obtain acrylic emulsion.
[0034] (3) Mix EP-KH with acrylic emulsion (mass ratio 2:1) in proportion, stir for 2 hours, adjust the pH to 7-8 with ammonia water, and filter to obtain modified epoxy emulsion.
[0035] Comparative Example 2 (without aminosilanes, without core-shell emulsions) The preparation steps of the aqueous epoxy resin emulsion in this embodiment are as follows: (1) 100g of E-44 epoxy resin was stirred at 80℃ and 200r / min, and 8g of KH-570 and 0.5g of triethylamine were added. The mixture was reacted at a constant temperature for 2h to obtain monosilane modified epoxy resin (EP-KH).
[0036] (2) Add 200mL of deionized water, 3g of SDS and 4.5g of OP-10 to a three-necked flask and mix well. Then add 100g of EP-KH and 5g of modified nano silica sol KH-SS and mix well. Add acrylic monomer mixture (MMA 36g, BA 18g, AA 6g) and 0.5g of APS. Polymerize at 75℃ for 3h. After post-treatment, obtain modified epoxy emulsion.
[0037] Comparative Example 3 To compare the performance of the product of this invention, a foreign waterborne epoxy emulsion 3961-1 was selected.
[0038] Comparative Example 4 To compare the performance of the product of this invention, a domestic waterborne epoxy emulsion FK403 was selected.
[0039] Test example: The modified epoxy emulsions prepared in Examples 1-3 and the epoxy emulsions in Comparative Examples 1-4 were subjected to performance tests. The test results are shown in the table below: Table 1. Test data of epoxy emulsion performance indicators for Examples 1-3 and Comparative Examples 1-4 Appearance (visual assessment) milky white liquid milky white liquid milky white liquid milky white liquid milky white liquid milky white liquid milky white liquid Solid content (%) 40.2 39.4 41.7 38.6 39.3 53 48 Viscosity (mPa·s) 650 620 680 610 590 690 740 Particle size (μm), D90 0.26 0.27 0.29 0.35 0.39 0.55 0.70 Thermal storage stability (50℃, 30d) No layering, no sedimentation No layering, no sedimentation No layering, no sedimentation Slight stratification Slight stratification Slight stratification Severe stratification Stability at room temperature (120 days) No layering, no sedimentation No layering, no sedimentation No layering, no sedimentation Slight stratification, sedimentation Slight stratification Slight stratification Severe stratification Mechanical stability (3000 r / min, 30 min) Homogeneous, without stratification Homogeneous, without stratification Homogeneous, without stratification Slight stratification Slight stratification Slight stratification Severe stratification Dilution stability (3%, 72h) No layering, no sedimentation No layering, no sedimentation No layering, no sedimentation Slight stratification Slight stratification Slight stratification Severe stratification
[0040] Note: The test standards for the above performance indicators are as follows: non-volatile matter, viscosity, particle size, thermal storage stability, room temperature storage stability, mechanical stability, and dilution stability: GB / T 11175-2021.
[0041] This invention employs a three-step synergistic process of molecular pre-assembly, in-situ grafting, and core-shell emulsification to synthesize a ternary interpenetrating core-shell epoxy emulsion in one step. Compared with the comparative example, the epoxy resin emulsion of this invention exhibits a narrow and small particle size distribution (D90: 0.26μ2), excellent room temperature stability and thermal storage (50℃, 30 days) stability without stratification or precipitation, and excellent mechanical stability and dilution stability without stratification or precipitation.
[0042] The above are merely preferred embodiments of the present invention and do not constitute any limitation on the present invention. Any equivalent substitutions or modifications made by those skilled in the art to the technical solutions and content disclosed in the present invention without departing from the scope of the present invention shall be deemed to have remained within the protection scope of the present invention.
Claims
1. A method for preparing a bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion, characterized in that: Includes the following steps: (1) Heat and stir the epoxy resin, add silane coupling agent and catalyst with functional groups, and react at a constant temperature to obtain end-modified epoxy resin EP-Sca. (2) After hydrolyzing the silane coupling agent, it was added dropwise into the nano silica sol, the pH was adjusted, and the mixture was filtered to obtain the modified nano silica sol KH-SS; (3) Take deionized water, add emulsifier and stir to dissolve, add part of EP-Sca from step (1) and KH-SS from step (2), and ultrasonically disperse to form a pre-emulsion; Nitrogen gas is introduced by heating, an initiator is added, and the reaction is carried out at a constant temperature to obtain seed emulsion; (4) The remaining EP-Sca and acrylic monomer mixture from step (1) is added dropwise to the seed emulsion. After the dropwise addition is complete, an initiator is added, and the temperature is raised to form a core-shell structure. After the reaction is complete, the temperature is lowered to adjust the pH, and the mixture is filtered to obtain the modified epoxy resin emulsion.
2. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 1, characterized in that: The epoxy resin mentioned in step (1) is at least one of E-20, E-44, and E-51.
3. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 1, characterized in that: The silane coupling agent with functional groups mentioned in step (1) is at least one of KH-550, KH-570, KH-602, and KH-792.
4. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 3, characterized in that: The silane coupling agent with functional groups mentioned in step (1) is a compound of KH-570 and KH-550, or a compound of KH-570 and KH-792.
5. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 1, characterized in that: The nano-silica sol in step (2) has a particle size of 20-50 nm, a silica content of 20%-40%, and a modified nano-silica sol solid content of 10%-30%.
6. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 1, characterized in that: The emulsifier mentioned in step (3) is at least one of sodium dodecyl sulfate, dodecylphenol polyoxyethylene ether, and nonylphenol polyoxyethylene ether.
7. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 6, characterized in that: The emulsifier is a compound of sodium dodecyl sulfate and dodecylphenol polyoxyethylene ether, or a compound of sodium dodecyl sulfate and nonylphenol polyoxyethylene ether.
8. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 1, characterized in that: The initiator mentioned in steps (3) and (4) is at least one of benzoyl peroxide, potassium persulfate, and sodium bisulfite.
9. The method for preparing the bissilane synergistic molecular pre-assembly-in-situ grafted core-shell epoxy resin emulsion according to claim 1, characterized in that: The acrylic monomer mixture in step (4) is at least one of methyl methacrylate, butyl acrylate, acrylic acid or ethyl acrylate; the added initiator accounts for 5% to 50% of the total mass of the initiator added in steps (3) and (4); the modified epoxy resin emulsion has a solid content of 35% to 45% and a viscosity of 400 to 1000 mPa·s at 25°C.
10. A bissilane co-assembled molecular pre-assembled in-situ grafted core-shell epoxy resin emulsion prepared by the method of any one of claims 1-9.