Composite epoxy group emulsifier for waterborne epoxy and method for preparing waterborne epoxy resin emulsion by using composite epoxy group emulsifier

Abstract

The invention discloses a composite epoxy group emulsifier for waterborne epoxy and a method for preparing waterborne epoxy resin emulsion by using the composite epoxy group emulsifier, and belongs to the technical field of waterborne coatings. The preparation method comprises the following steps: synthesizing a polyoxyethylene ether type epoxy emulsifier from epoxy resin, methoxypolyethylene glycol and maleic anhydride, and synthesizing a sulfonic acid type epoxy emulsifier from epoxy resin, sodium sulfanilate and o-toluene glycidyl ether; the two emulsifiers are prepared into a compound emulsifier, and the waterborne epoxy emulsion is prepared by using the compound emulsifier through a phase inversion technology. The two emulsifiers are compounded according to an optimized ratio to form a synergistic adsorption effect on an oil-water interface, so that the interfacial tension is remarkably reduced, and the emulsion stability is enhanced. Compared with a single emulsification system, the method has the advantages that the use amount of the emulsifier can be remarkably reduced, the average particle size of the waterborne epoxy emulsion is reduced, the storage stability is improved, the problems of large use amount and non-uniform emulsion particle size distribution of the traditional emulsifier are effectively solved, and the method has important application value in the fields of building coatings, industrial corrosion prevention and the like.

Description

Technical Field

[0001] The invention belongs to the field of waterborne epoxy emulsion preparation, and particularly relates to a reactive emulsifier synthesis technology and waterborne epoxy emulsion preparation. Background Art

[0002] Epoxy resin, with its exceptional performance, is widely used in various fields, including construction, electronics, and machinery manufacturing. Its low-temperature curing properties are particularly well-suited for structural reinforcement and material bonding in the construction industry, while its excellent electrical insulation and heat resistance make it crucial in the manufacture of electronic components and integrated circuits. Furthermore, its impact resistance and durability make it a preferred material for specialty materials. However, the use of traditional epoxy resins faces environmental challenges. Their reliance on organic solvents makes them difficult to dissolve in water, leading to volatile organic compound (VOC) emissions that are inconsistent with current high environmental standards. Compared to traditional solvent-based coatings, water-based coatings offer advantages such as low cost, ease of availability, safety, and environmental friendliness. Among many water-based coatings, water-based epoxy resin coatings have attracted widespread attention and application due to their strong adhesion to heterogeneous substrates, corrosion resistance, and excellent mechanical properties. However, epoxy resins are insoluble in water and are both hydrophobic and thermosetting. If epoxy resins are used in waterborne epoxy coatings to achieve excellent mechanical properties and corrosion resistance of the coatings, two issues need to be addressed: hydration of the epoxy resin and application of an appropriate curing agent.

[0003] In recent years, with growing environmental awareness and the need for sustainable development, water-based epoxy emulsions have garnered widespread attention. Compared to traditional epoxy coatings that rely on organic solvents, water-based epoxy coatings significantly reduce the need for organic solvents by using water as a solvent. Emulsifiers play a crucial role in this transformation. Since epoxy resins are inherently insoluble in water, emulsifiers transform them into water-soluble or water-dispersible forms, enabling the production of water-based epoxy coatings. However, the choice and dosage of emulsifiers have a direct impact on the stability of water-based epoxy coatings.

[0004] To address this issue, this paper designed and synthesized two epoxy resin emulsifier monomers that possess both emulsifying ability and reactivity with polyamine epoxy curing agents. This reactivity allows the epoxy resin emulsifier to anchor onto the coating through reaction during film curing of the waterborne epoxy emulsion, preventing migration and also enhancing the mechanical and thermal properties of the coating. By combining the two emulsifier monomers, the composite emulsifier exerts a synergistic effect, significantly reducing the amount of emulsifier added while producing a stable waterborne epoxy emulsion. This provides an effective approach for preparing more stable emulsions and promotes the development of waterborne epoxy resin and other emulsion products towards more environmentally friendly and efficient approaches. Summary of the Invention

[0005] The application provides two epoxy-based emulsifiers for waterborne epoxy resin, by compounding self-made polyoxyethylene ether type epoxy-based emulsifier and sulfonic acid type epoxy-based emulsifier, the synergistic effect of the composite emulsifier is achieved, the addition amount of the emulsifier is greatly reduced, and a stable waterborne epoxy emulsion is prepared.

[0006] The specific method is as follows: (1) polyoxyethylene ether type epoxy-based emulsifier is synthesized by using epoxy resin, polyethylene glycol monomethyl ether and maleic anhydride; (2) sulfonic acid type epoxy-based emulsifier is synthesized by using epoxy resin, sodium p-aminobenzenesulfonate and o-cresyl glycidyl ether; (3) the polyoxyethylene ether type epoxy-based emulsifier and the sulfonic acid type epoxy-based emulsifier are mixed in proportion to obtain a composite epoxy-based emulsifier, the composite epoxy-based emulsifier is uniformly mixed with epoxy resin, and under certain temperature, by phase inversion, the water is added under the action of high shear force to form a stable waterborne epoxy resin emulsion; In the synthesis method of the epoxy-based emulsifier, the epoxy resin is E51 type, E44 type or E20 type epoxy resin, and the epoxy equivalent weight is 200-500; As preferred, the epoxy resin used for synthesizing the polyoxyethylene ether type emulsifier is consistent with the type of the main epoxy resin in the epoxy resin emulsion.

[0007] As preferred, the epoxy resin used for synthesizing the sulfonic acid type emulsifier is E-51 type; if E44 is used, the effect is not good, and if E20 is used, no reaction occurs.

[0008] In the preparation method of the polyoxyethylene ether type epoxy-based emulsifier, the mass ratio of the epoxy resin, polyethylene glycol monomethyl ether and maleic anhydride is 1:1:1; In the preparation method of the sulfonic acid type epoxy-based emulsifier, the mass ratio of the epoxy resin, sodium p-aminobenzenesulfonate and o-cresyl glycidyl ether is 1:1:1; In the synthesis reaction of the polyoxyethylene ether type epoxy-based emulsifier in step (1) and the sulfonic acid type epoxy-based emulsifier in step (2), the temperature is 80-110 DEG C; In the preparation method of the waterborne epoxy emulsion, the proportion of the composite epoxy resin epoxy-based emulsifier added in step (3) is 10%-30% of the total mass of the epoxy resin; as preferred, the proportion of the epoxy resin reaction emulsifier added is 15%-30% of the total mass of the epoxy resin; In the preparation method of the waterborne epoxy emulsion, the mass ratio of the emulsifiers in steps (1) and (2) is (6-1):(1-3); as preferred, the mass ratio of the polyoxyethylene ether type epoxy-based emulsifier and the sulfonic acid type epoxy-based emulsifier is 1:1-4:1; In the preparation method of the water-based epoxy emulsion, the phase inversion temperature is 65°C.

[0009] Advantages of the present invention: Two epoxy emulsifiers with both reactivity and emulsification capabilities were designed and synthesized, enabling the formation of a water-based epoxy resin. The use of a composite emulsifier can fully utilize the synergistic and complementary effects between different surfactants, an effect known as the synergistic effect in interface science, effectively improving emulsification performance, reducing the emulsion particle size, and significantly increasing the emulsion stability. Due to the synergistic properties of the composite emulsifier, when the composite emulsifier is used in a reduced amount compared to a single emulsifier system, a stable water-based epoxy emulsion can still be obtained, and the emulsion particle size is smaller.

[0010] Furthermore, waterborne epoxy cured films prepared using a composite emulsifier system exhibit higher water contact angles, better water resistance, and enhanced heat resistance compared to single emulsifier systems. This provides an effective approach for preparing more stable emulsions and promotes the development of waterborne epoxy resins and their cured film products towards greater environmental friendliness and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 :For the polyoxyethylene ether epoxy emulsifier E of Example 1 51 MAMPEG 5000 Infrared spectrogram; Figure 2 : This is the infrared spectrum of the sulfonic acid type anionic epoxy resin emulsifier ESSGME in Example 1; Figure 3 : A comparison diagram of particle size potentials of polyoxyethylene ether epoxy emulsifier compounded emulsions with different epoxy resin structures corresponding to Examples 1, 2 and 3; Figure 4 : A comparison diagram of the potential and particle size of the waterborne epoxy emulsion at different compounding ratios of Examples 3 to 8; Figure 5 : A comparison diagram of the particle size and potential of the water-based epoxy emulsions at different compound emulsifier contents in Examples 3, 9 and 11. DETAILED DESCRIPTION

[0011] Implementation Case 1: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-51 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 51 MAMPEG 5000 Its infrared spectrum is attached. Figure 1 .

[0012] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst, and the reaction was carried out under condensation reflux at 80°C for 2 hours, then the temperature was raised to 110°C and the reaction was continued for 3 hours. After the first stage reaction was completed, 0.025 mol of epoxy resin E-51 was added and the reaction was continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain a light brown viscous liquid ESSGME. Its infrared spectrum is shown in the attached figure. Figure 2 .

[0013] (2) Preparation of epoxy resin emulsion Add 20g E-51 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 51 MAMPEG 5000 The mass ratio of ESSGME to emulsifier is 1:1, the content of compound emulsifier is 15% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. The high-speed stirring is continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 332 nm and a Zeta potential value of -33.8 mV. See the attached Figure 3 .

[0014] Implementation Case 2: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-44 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 44 MAMPEG 5000 .

[0015] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt% tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0016] (2) Preparation of epoxy resin emulsion Add 20g E-51 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 44 MAMPEG 5000 The mass ratio of ESSGME to epoxy resin was 1:1, the content of the composite emulsifier was 15% of the epoxy resin mass, the emulsification temperature was 65 °C, and the solid content of the emulsion was (50±2)%. After the composite emulsifier and epoxy resin were uniformly stirred, deionized water was added dropwise into the flask under a high shear force of 1000 r / min until the viscosity of the system suddenly decreased. At this time, the system changed from an oil-in-water system to a water-in-oil system, and a phase inversion occurred. The high-speed stirring was continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 286 nm and a Zeta potential of -32.4 mV. See the attached Figure 3 .

[0017] Implementation Case 3: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0018] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0019] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000 The mass ratio of ESSGME to emulsifier is 1:1, the content of compound emulsifier is 15% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. High-speed stirring is continued for 1 hour to obtain a milky white and stable epoxy resin emulsion with a particle size of 223 nm and a Zeta potential value of -43.2 mV. See attached. Figure 3 The emulsion was left to stand for 24 hours and the emulsion was stable.

[0020] Thoroughly mix the stabilized epoxy emulsion from Example 3 with the epoxy curing agent (Huntsman AD3986) to ensure consistency. Stir continuously to evenly disperse the epoxy resin throughout the emulsion. Allow the mixture to settle, then apply the cured epoxy resin coating evenly to the tinplate using an applicator and allow to dry completely. Optimal coating performance was achieved when the epoxy emulsion to curing agent ratio was 1:0.7. The water-based epoxy cured film exhibited a water contact angle of 74.4°, a water absorption of 4.8%, a glass transition temperature of 59.70°C, and a thermal decomposition temperature of 388.7°C.

[0021] Implementation Case 4: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0022] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0023] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000 The mass ratio of ESSGME to epoxy resin was 6:1, the content of the composite emulsifier was 15% of the epoxy resin mass, the emulsification temperature was 65 °C, and the solid content of the emulsion was (50 ± 2)%. After the composite emulsifier and epoxy resin were uniformly stirred, deionized water was added dropwise into the flask under a high shear force of 1000 r / min until the viscosity of the system suddenly decreased. At this time, the system changed from an oil-in-water system to a water-in-oil system, and a phase reversal occurred. The high-speed stirring was continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 348 nm and a Zeta potential of -34.2 mV. See the attached Figure 4 .

[0024] Implementation Case 5: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0025] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0026] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to epoxy resin was 4:1, the content of the composite emulsifier was 15% of the epoxy resin mass, the emulsification temperature was 65 °C, and the solid content of the emulsion was (50±2)%. After the composite emulsifier and epoxy resin were uniformly stirred, deionized water was added dropwise into the flask under a high shear force of 1000 r / min until the viscosity of the system suddenly decreased. At this time, the system changed from an oil-in-water system to a water-in-oil system, and a phase reversal occurred. The high-speed stirring was continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 257 nm and a Zeta potential of -42.6 mV. See the attached Figure 4 .

[0027] Implementation Case 6: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0028] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0029] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to epoxy resin was 2:3, the content of the composite emulsifier was 15% of the epoxy resin mass, the emulsification temperature was 65 °C, and the solid content of the emulsion was (50±2)%. After the composite emulsifier and epoxy resin were uniformly stirred, deionized water was added dropwise into the flask under a high shear force of 1000 r / min until the viscosity of the system suddenly decreased. At this time, the system changed from an oil-in-water system to a water-in-oil system, and a phase reversal occurred. The high-speed stirring was continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 219 nm and a Zeta potential value of -42.3 mV. See the attached Figure 4 .

[0030] Implementation Case 7: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0031] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0032] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to emulsifier is 1:2, the content of compound emulsifier is 15% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. High-speed stirring is continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 249 nm and a Zeta potential value of -38.3 mV. See attached. Figure 4 .

[0033] Implementation Case 8: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0034] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0035] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to emulsifier is 1:3, the content of compound emulsifier is 15% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. High-speed stirring is continued for 1 hour to obtain a milky white and stable epoxy resin emulsion with a particle size of 491 nm and a Zeta potential value of -31.2 mV. See attached. Figure 4 .

[0036] As shown in Examples 3-8, when the ratio of the two emulsifiers is between 1:1 and 2:3, the emulsion particle size is minimized and the absolute value of the zeta potential is highest. At this point, the synergistic effect is strongest and the emulsion is most stable. When the ratio of either emulsifier is too high or too low (e.g., 6:1 or 1:3), the emulsion stability decreases.

[0037] Implementation Case 9: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0038] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0039] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to emulsifier is 1:1, the content of compound emulsifier is 10% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier emulsion and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. High-speed stirring is continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 671 nm and a Zeta potential value of -30.4 mV. See attached. Figure 5 .

[0040] Implementation Case 10: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0041] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0042] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to emulsifier is 1:1, the content of compound emulsifier is 20% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. High-speed stirring is continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 216 nm and a Zeta potential value of -44.3 mV. See attached. Figure 5 .

[0043] Implementation Case 11: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0044] 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt % propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0045] (2) Preparation of epoxy resin emulsion Add 20g E-20 epoxy resin into a single-necked flask and add the compound emulsifier, of which E 20 MAMPEG 5000The mass ratio of ESSGME to emulsifier is 1:1, the content of compound emulsifier is 30% of the mass of epoxy resin, the emulsification temperature is 65 ℃, and the solid content of the emulsion is (50±2)%. After the compound emulsifier and epoxy resin are uniformly stirred, deionized water is added dropwise into the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreases. At this time, the system changes from an oil-in-water system to a water-in-oil system, and a phase reversal occurs. High-speed stirring is continued for 1 hour to obtain a milky white stable epoxy resin emulsion with a particle size of 189 nm and a Zeta potential value of -44.9 mV. See attached. Figure 5 .

[0046] Comparative Example 1: (1) Preparation of epoxy emulsifier 0.01 mol of dehydrated polyethylene glycol monomethyl ether 5000 and 0.01 mol of maleic anhydride were added to a three-necked flask, heated to 80°C to melt, then heated to 110°C and continued to react for 5 hours, 0.01 mol of E-20 epoxy resin was added, heated to 110°C and continued to react for 5 hours to obtain polyoxyethylene ether epoxy emulsifier E 20 MAMPEG 5000 .

[0047] (2) Preparation of epoxy resin emulsion Add 20g of E-20 epoxy resin into a single-necked flask and add only a single emulsifier E 20 MAMPEG 5000 The emulsifier content was 15% of the epoxy resin mass, the emulsification temperature was 65°C, and the solids content of the emulsion was (50 ± 2)%. After the emulsifier and epoxy resin were uniformly stirred, deionized water was added dropwise to the flask under high shear force of 1000 r / min until the viscosity of the system suddenly decreased, indicating that the system transformed from an oil-in-water system to a water-in-oil system, a phase inversion. High-speed stirring was continued for 1 hour to obtain a milky white epoxy resin emulsion with a particle size of 536 nm and a zeta potential of -5.8 mV. After standing for 4 hours, the emulsion became unstable and sank. The epoxy emulsion was mixed with an epoxy curing agent (Huntsman AD3986) in a ratio of 1:0.7. The water contact angle of the waterborne epoxy cured film was measured to be 68.1° and the water absorption was 7.8%. The glass transition temperature was 46.32°C, and the thermal decomposition temperature was 323.1°C.

[0048] Comparative Example 2: (1) Preparation of epoxy emulsifier 0.025 mol of sodium p-aminobenzenesulfonate was dissolved in water at 80 °C, and 0.025 mol of o-toluene glycidyl ether and 30% of monomer were added dropwise. wt% propylene glycol methyl ether acetate mixture, and add monomer 0.05 wt % tetrabutylammonium bromide was used as a catalyst. The reaction was refluxed at 80°C for 2 hours, then heated to 110°C for 3 hours. After the first stage of reaction, 0.025 mol of epoxy resin E-51 was added and the reaction continued for 5 hours. After the reaction was completed, the water and solvent in the system were removed by vacuum distillation to obtain ESSGME as a light brown viscous liquid.

[0049] (2) Preparation of epoxy resin emulsion To a single-necked flask, 20 g of E-20 epoxy resin was added, along with a single anionic emulsifier, ESSGME, at a concentration of 20% by mass based on the epoxy resin. The emulsification temperature was 65 °C, and the solids content of the emulsion was (50 ± 2)%. After the emulsifier and epoxy resin were uniformly stirred, deionized water was added dropwise to the flask under a high shear force of 1000 r / min until the viscosity of the system suddenly decreased, at which point the system transitioned from an oil-in-water system to an oil-in-water system. The mixture was stirred at high speed for 1 hour to form an epoxy resin emulsion with a particle size of 676 nm and a zeta potential of -4.1 mV. After standing for 1 hour, the emulsion became unstable, precipitated, and separated into layers.

[0050] Comparative Example 3: Add 20g of E-20 epoxy resin to a single-necked flask without adding any emulsifier. The temperature is 65°C. Under the action of high shear force of 1000r / min, deionized water is added dropwise to the flask. After continuing high-speed stirring for 1 hour, if there is no obvious change in the viscosity of the system, stop stirring and the epoxy resin and water will immediately separate.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A composite epoxy emulsifier for waterborne epoxy, characterized in that, It is obtained by compounding polyoxyethylene ether epoxy emulsifier and sulfonic acid epoxy emulsifier; the specific components of the emulsifier are as follows: Polyoxyethylene ether type epoxy emulsifier: prepared by the reaction of epoxy resin, polyethylene glycol monomethyl ether and maleic anhydride; Sulfonic acid epoxy emulsifier: prepared by the reaction of epoxy resin, sodium p-aminobenzenesulfonate and o-toluene glycidyl ether.

2. The composite epoxy emulsifier for waterborne epoxy according to claim 1, characterized in that The epoxy equivalent weight of the epoxy resin used to synthesize the emulsifier is between 200 and 500 g / eq.

3. The composite epoxy emulsifier for waterborne epoxy according to claim 1, characterized in that In the preparation of the polyoxyethylene ether type epoxy emulsifier, the molar ratio of epoxy resin, polyethylene glycol monomethyl ether and maleic anhydride is 1:1:

1.

4. The composite epoxy emulsifier for waterborne epoxy according to claim 1, characterized in that In the preparation of the sulfonic acid epoxy emulsifier, the molar ratio of epoxy resin, sodium p-aminobenzenesulfonate and o-toluene glycidyl ether is 1:1:

1.

5. The composite epoxy emulsifier for water-based epoxy according to claim 1, characterized in that In the preparation of polyoxyethylene ether type epoxy emulsifier and sulfonic acid type epoxy emulsifier, the reaction temperature is 80~110℃.

6. The composite epoxy emulsifier for waterborne epoxy according to claim 1, characterized in that In the composite epoxy emulsifier, the mass ratio of the polyoxyethylene ether epoxy emulsifier to the sulfonic acid epoxy emulsifier is (6-1):(1-3).

7. A method for preparing a water-based epoxy resin emulsion, characterized in that: The following steps are involved: (1) uniformly mixing the composite epoxy emulsifier according to any one of claims 1 to 6 with the epoxy resin; (2) Under a certain temperature and high shear force, water is added dropwise to the mixture of step (1) to form an oil-in-water emulsion by a phase inversion method to obtain the water-based epoxy resin emulsion.

8. The method for preparing the aqueous epoxy resin emulsion according to claim 7, wherein: The content of the compound emulsifier prepared by polyoxyethylene ether epoxy emulsifier and sulfonic acid epoxy emulsifier is 10%-30% of the mass of the epoxy resin.

9. The method for preparing the aqueous epoxy resin emulsion according to claim 7, wherein: The temperature of the phase inversion was 65°C.

10. A water-based epoxy resin emulsion, characterized in that Prepared by the method according to any one of claims 7 to 9.

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