Epoxy modified acrylic emulsion as well as preparation method and application thereof

Abstract

The invention relates to the technical field of metal anti-corrosion emulsions, in particular to an epoxy modified acrylic emulsion as well as a preparation method and application thereof, and the epoxy modified acrylic emulsion comprises the following raw materials in parts by weight: 30-40 parts of styrene; 1 to 10 parts of acrylic epoxy phosphate resin; 10 to 20 parts of methyl methacrylate; 5 to 10 parts of n-butyl methacrylate; 30 to 35 parts of 2-ethylhexyl acrylate; 2-5 parts of methacrylic acid; 2 to 5 parts of acrylamide; 1 to 3 parts of caprolactone modified acrylate monomer; 5-8 parts of an emulsifier; 0.3 to 0.6 part of an initiator; and 80 to 150 parts of deionized water. The special hard monomer, the soft monomer and the functional monomer are reasonably matched, and the acrylate monomer connected to the epoxy resin chain segment has good compatibility with other acrylate monomers, so that the dispersity and stability of the epoxy resin in the emulsion are improved, and the metal anti-rust and anti-corrosion performance of the emulsion is improved.

Description

Technical Field

[0001] This invention relates to the field of metal corrosion-resistant emulsion technology, and in particular to an epoxy-modified acrylic emulsion, its preparation method, and its application. Background Technology

[0002] As a key load-bearing and transmission component of the vehicle chassis system, the axle is exposed to a complex, variable and harsh environment for a long time. It not only bears severe mechanical vibration and impact loads, but also faces continuous erosion from various corrosive media such as rainwater, humid atmosphere, mud and even acid and alkali fumes in industrial areas.

[0003] Currently, water-based acrylic emulsions are widely used as film-forming substances in the anti-corrosion coating of vehicle axles. Water-based acrylic emulsions possess strong chemical stability and are not easily chemically degraded. They maintain good weather resistance and corrosion resistance when exposed to external environmental factors such as humidity, acid rain, and ultraviolet radiation, thus being widely used in metal corrosion protection. However, existing water-based acrylic emulsions suffer from poor salt spray resistance, limiting their application in the vehicle axle field. Summary of the Invention

[0004] To address the problem of poor salt spray resistance in existing waterborne acrylic emulsions, this invention provides an epoxy-modified acrylic emulsion. This epoxy-modified acrylic emulsion, through the rational combination of hard monomers, soft monomers, and functional monomers, facilitates the formation of a dense interpenetrating network structure, thereby improving the emulsion's salt spray resistance and solving the problem of poor salt spray resistance in existing waterborne acrylic emulsions.

[0005] The technical solution adopted by this invention to solve its technical problem is: An epoxy-modified acrylic emulsion, comprising the following components by weight: 30-40 parts styrene; 1-10 parts of acrylic epoxy phosphate resin; 10-20 parts of methyl methacrylate; 5-10 parts of n-butyl methacrylate; 30-35 parts of isooctyl acrylate; 2-5 parts methacrylic acid; Acrylamide 2-5 parts; 1-3 parts of caprolactone-modified acrylate monomer; 5-8 parts emulsifier; Initiator 0.3-0.6 parts; 80-150 parts of deionized water.

[0006] Optionally, the preparation method of the acrylic epoxy phosphate resin is as follows: add epoxy resin to a solvent, heat to 100°C to dissolve, add N,N-dimethylbenzylamine, and then add acrylic acid dropwise; after the dropwise addition is completed, heat to 105-125°C to react; after the reaction is completed, cool to 70°C, add phosphoric acid to carry out esterification reaction, and obtain acrylic epoxy phosphate resin.

[0007] Optionally, the epoxy resin is a bisphenol A type epoxy resin.

[0008] Optionally, the solvent is dipropylene glycol dimethyl ether.

[0009] Optionally, the mass ratio of the epoxy resin, the solvent, the N,N-dimethylbenzylamine, the acrylic acid, and the phosphoric acid is (150-750):(70-280):0.33:(30-80):(8-15).

[0010] Optionally, the emulsifier is selected from at least one of reactive anionic emulsifiers and reactive nonionic emulsifiers.

[0011] Optionally, the reactive anionic emulsifier is selected from at least one of allyloxy polyoxyethylene ether ammonium sulfate and allyloxy polyoxyethylene ether phosphate; the reactive nonionic emulsifier is allyloxy polyoxyethylene ether.

[0012] Optionally, the initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0013] Another object of the present invention is to provide a method for preparing the epoxy-modified acrylic emulsion as described above, characterized by comprising the following steps: S1: By weight, mix 2-5 parts of emulsifier with 25 parts of deionized water, then add 30-40 parts of styrene, 1-10 parts of epoxy phosphate acrylate resin, 10-20 parts of methyl methacrylate, 5-10 parts of n-butyl methacrylate, 30-35 parts of isooctyl acrylate, 2-5 parts of methacrylic acid, 2-5 parts of acrylamide, and 1-3 parts of caprolactone-modified acrylate monomer, and stir to form a pre-emulsion. S2: Dissolve 0.1-0.2 parts of the initiator in 2 parts of deionized water to obtain the first initiator solution; S3: Dissolve the remaining initiator in 10 parts of deionized water to obtain the second initiator solution; S4: Mix 85 parts of deionized water and the remaining emulsifier, heat, and obtain the base liquid; S5: After adding a portion of pre-emulsion to the base liquid, add the first initiator solution and react at 75-85℃ to obtain a reaction solution; S6: Add the remaining pre-emulsion and the second initiator solution to the reaction solution, and react at 75-85℃ to obtain an epoxy-modified acrylic emulsion.

[0014] Another object of the present invention is to provide an application of the epoxy-modified acrylic emulsion as described above in metal rust and corrosion prevention.

[0015] The beneficial effects of this invention are: The epoxy-modified acrylic emulsion provided by this invention improves the weather resistance of the emulsion by rationally combining special hard monomers, soft monomers, and functional monomers, adding long carbon chain monomers, and utilizing the good compatibility between the acrylate monomers attached to the epoxy resin segments and other acrylate monomers to improve the dispersibility and stability of the epoxy resin in the emulsion. This ensures that the epoxy resin is completely encapsulated by the emulsion system, which is conducive to the formation of a dense interpenetrating network structure and enhances the metal rust and corrosion prevention performance of the emulsion. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a particle size distribution of the epoxy-modified acrylic emulsion prepared in Example 4 of this invention. Detailed Implementation

[0018] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] To address the problem of poor salt spray resistance in existing water-based acrylic emulsions, this invention provides an epoxy-modified acrylic emulsion, wherein the raw materials of this epoxy-modified acrylic emulsion comprise the following components by weight: 30-40 parts styrene; 1-10 parts of acrylic epoxy phosphate resin; 10-20 parts of methyl methacrylate; 5-10 parts of n-butyl methacrylate; 30-35 parts of isooctyl acrylate; 2-5 parts methacrylic acid; Acrylamide 2-5 parts; 1-3 parts of caprolactone-modified acrylate monomer; 5-8 parts emulsifier; Initiator 0.3-0.6 parts; 80-150 parts of deionized water.

[0020] Currently, to improve the salt spray resistance of single-component acrylic emulsions, epoxy resins are commonly used to modify them. However, epoxy resins are lipophilic and insoluble in water. Direct addition of epoxy resins may disrupt the balance between the surfactant and the aqueous phase in the emulsion system, leading to compromised emulsion stability. The epoxy resin may also detach from the acrylic polymer and fail to be encapsulated by the acrylic emulsion, thus hindering its salt spray resistance. Therefore, this invention introduces an acrylic epoxy phosphate resin, an oligomer containing double bonds, epoxy groups, and a phosphate ester structure. It is through these double-bond functional groups that the acrylic epoxy phosphate resin can undergo free radical polymerization. The reaction is incorporated into the acrylic emulsion, improving the dispersibility and stability of the epoxy resin in the emulsion, ensuring that the epoxy resin is completely encapsulated by the emulsion system, which is conducive to the formation of a dense interpenetrating network structure and enhances the metal rust and corrosion resistance of the emulsion. Furthermore, since the phosphate ester structure is a hydrophilic structure, the introduction of the phosphate ester structure also helps to increase the stability of the emulsion, preventing the epoxy resin from detaching from the acrylic polymer, thus avoiding the inability of the epoxy resin to be encapsulated by the acrylic emulsion and thus achieving better salt spray resistance. The present invention, through the acrylic epoxy phosphate ester resin, ensures that the prepared acrylic emulsion segments not only contain epoxy structures but also phosphate ester structures, which helps to improve weather resistance and adhesion while increasing salt spray resistance.

[0021] Specifically, in the raw materials of this epoxy-modified acrylic emulsion, styrene and methyl methacrylate serve as hard monomers. The introduction of hard monomers makes the microstructure of the emulsion more compact, increases the solid content of the emulsion, and enhances the hardness and wear resistance of the emulsion film. Simultaneously, these hard monomers possess strong chemical resistance, improving the emulsion film's resistance to chemical corrosion, atmospheric damage, and moisture erosion. Isooctyl acrylate, as a soft monomer, enhances the flexibility and impact resistance of the emulsion film, improves its elasticity under harsh conditions, and enhances its weather resistance, allowing it to maintain excellent stability under natural light, ultraviolet radiation, or other environmental factors. It also improves the transparency and gloss of the emulsion film, enhancing the texture of metallic surfaces. Methacrylic acid, as a functional monomer, possesses strong polarity and hydrophilicity. It polymerizes with styrene and other acrylate monomers to form polymers, improving the emulsion film's adhesion, water resistance, and chemical resistance. Meanwhile, the introduction of caprolactone-modified acrylate monomers and isooctyl acrylate into the molecular chain improves the flexibility of the polymer, enabling better film formation. The preferred caprolactone-modified acrylate monomer in this invention is M-5300 from Toa Synthetic Co., Ltd., which effectively improves the polymer's flexibility without excessively reducing the hardness of the film. The introduction of isooctyl acrylate, as a long carbon chain, into the polymer chain segment improves the hydrophobicity of the film and enhances the interpenetrating network structure of the epoxy resin and acrylic emulsion, thereby improving the weather resistance and chemical resistance of the modified acrylic emulsion.

[0022] The epoxy-modified acrylic emulsion provided by this invention improves the weather resistance of the emulsion by rationally combining special hard monomers, soft monomers, and functional monomers, adding long carbon chain monomers, and utilizing the good compatibility between the acrylate monomers attached to the epoxy resin segments and other acrylate monomers to improve the dispersibility and stability of the epoxy resin in the emulsion. This ensures that the epoxy resin is completely encapsulated by the emulsion system, which is conducive to the formation of a dense interpenetrating network structure and enhances the metal rust and corrosion prevention performance of the emulsion.

[0023] Specifically, the preferred preparation method of the acrylic epoxy phosphate resin of the present invention is as follows: epoxy resin is added to a solvent, heated to 100°C to dissolve, N,N-dimethylbenzylamine is added, and then acrylic acid is added dropwise; after the dropwise addition is completed, the temperature is raised to 105-125°C to carry out the reaction; after the reaction is completed, the temperature is lowered to 70°C, and phosphoric acid is added to carry out the esterification reaction to obtain acrylic epoxy phosphate resin.

[0024] In this preparation process, the epoxy resin first undergoes an esterification reaction with the acrylic monomer, thus preserving the double bonds on the acrylic monomer. Then, the remaining epoxy groups react with the hydroxyl groups on the phosphoric acid to form an epoxy phosphate ester. This design, from a chemical structure perspective, yields an oligomer that contains double bonds, epoxy groups, and a phosphate ester structure.

[0025] The epoxy resin preferred in this invention is a bisphenol A type epoxy resin, and more preferably, the bisphenol A type epoxy resin is selected from at least one of epoxy resins NPEL127, NPEL128, NPEL134, NPSL901, NPSL902, and NPSL903. These epoxy resins have certain oleophilicity and good dispersibility, and can form a uniform dispersion system in the emulsion system, thus making it easier to be compatible with other components and encapsulate them in the emulsion to form a stable mixed system. The modified acrylic epoxy phosphate resin is relatively easy to encapsulate in the acrylic emulsion, which can improve the degree of crosslinking between the epoxy resin and the acrylic emulsion and improve the density of the emulsion film.

[0026] The preferred solvent in this invention is dipropylene glycol dimethyl ether (DMM).

[0027] In the preferred preparation process of the acrylic epoxy phosphate resin of this invention, the mass ratio of epoxy resin, solvent, N,N-dimethylbenzylamine, acrylic acid, and phosphoric acid is (150-750):(70-280):0.33:(30-80):(8-15); specifically, the preparation process can be carried out according to the following method: Add 70-280 parts of solvent DMM and 150-750 parts of bisphenol A epoxy resin to a flask by weight. Then heat to 100°C to dissolve. After complete dissolution, add 0.33 parts of N,N-dimethylbenzylamine. Add 30-80 parts of acrylic acid dropwise over 30 minutes. After the addition is complete, slowly heat to 105-125°C and maintain this temperature for 4-5 hours. Stop the reaction when the acid value is less than 1. Cool to 70°C and add 8-15 parts of 80% phosphoric acid to carry out the esterification reaction. Continue the reaction for 3-4 hours to obtain acrylic epoxy phosphate resin.

[0028] In this invention, the emulsifier in the epoxy-modified acrylic emulsion raw material is preferably selected from at least one of reactive anionic emulsifiers and reactive nonionic emulsifiers, and more preferably, the reactive anionic emulsifier is selected from at least one of allyloxy polyoxyethylene ether ammonium sulfate and allyloxy polyoxyethylene ether phosphate; the reactive nonionic emulsifier is allyloxy polyoxyethylene ether.

[0029] Specifically, the emulsifier of the present invention is preferably selected from at least one of allyloxy polyoxyethylene ether ammonium sulfate, allyloxy polyoxyethylene ether, and allyloxy polyoxyethylene ether phosphate, and is free of nonylphenol and environmentally friendly.

[0030] Specifically, the preferred allyloxy polyoxyethylene ether ammonium sulfate salt of this invention uses the Japanese company, IDC, product model SR10; the allyloxy polyoxyethylene ether uses the Japanese company, IDC, product model ER30; and the allyloxy polyoxyethylene ether phosphate uses the Japanese company, IDC, product model PP-70. The above-mentioned anionic emulsifier contains a phosphate ester structure, which can improve adhesion to metal substrates, thereby improving the salt spray resistance of the emulsion.

[0031] The initiator of this invention is preferably selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

[0032] The preferred initiator of this invention is a combination of potassium persulfate and ammonium persulfate.

[0033] This invention addresses the shortcomings of existing aqueous acrylic emulsion formulations by first providing a modified epoxy resin, and then using this modified epoxy resin to modify the acrylic emulsion. The main purpose is to improve the salt spray performance of the acrylic emulsion, and to enable the modified acrylic emulsion to not only have the weather resistance of the acrylic emulsion, but also to exhibit the salt spray resistance of the epoxy resin.

[0034] The glass transition temperature of the epoxy-modified acrylic emulsion is preferably 10~15℃.

[0035] Another object of the present invention is to provide a method for preparing the epoxy-modified acrylic emulsion as described above, the method comprising the following steps: S1: By weight, mix 2-5 parts of emulsifier with 25 parts of deionized water, then add 30-40 parts of styrene, 1-10 parts of epoxy phosphate acrylate resin, 10-20 parts of methyl methacrylate, 5-10 parts of n-butyl methacrylate, 30-35 parts of isooctyl acrylate, 2-5 parts of methacrylic acid, 2-5 parts of acrylamide, and 1-3 parts of caprolactone-modified acrylate monomer, and stir to form a pre-emulsion. S2: Dissolve 0.1-0.2 parts of the initiator in 2 parts of deionized water to obtain a first initiator solution; this first initiator solution is used to prepolymerize a portion of the pre-emulsion. S3: Dissolve the remaining initiator in 10 parts of deionized water to prepare a second initiator solution; The second initiator solution is used to rapidly initiate the polymerization reaction; S4: Mix 85 parts of deionized water and the remaining emulsifier, heat, and stir evenly to obtain the base liquid; S5: After adding a portion of the pre-emulsion to the base liquid, add the first initiator solution, react at 75-85℃, keep warm, and obtain the reaction solution; Prepolymerization in this step allows monomers to be distributed more evenly in the system, stabilizes the emulsification process, helps control the size of dispersed phase particles, ensures that the chemical reactions that occur during emulsion formation can proceed evenly, improves emulsion stability, and helps reduce unreacted monomer residues, ensuring the smooth progress of subsequent reactions. S6: Add the remaining pre-emulsion and the second initiator solution to the reaction solution. The preferred method of addition is dropwise addition, and the dropwise addition time is preferably controlled at 200-240 min. React at 75-85℃ to obtain epoxy-modified acrylic emulsion.

[0036] In the preferred embodiment of the present invention, the amount of pre-emulsion added in step S5 is 5-10% of the total weight of the pre-emulsion.

[0037] In this invention, after the pre-emulsion and the second initiator solution are added dropwise, the material is cooled. When the emulsion cools to below 60°C, ammonia and deionized water are added to adjust the pH of the emulsion to 7-8, making the emulsion neutral and more stable. Finally, the emulsion is filtered to obtain an epoxy-modified acrylic emulsion.

[0038] The epoxy-modified acrylic emulsion prepared in this invention preferably has a D50 particle size of 100~150nm; the D50 particle size of the emulsion is effectively controlled by prepolymerization, thereby improving the stability of the emulsion system and utilizing the compounding of specific emulsifiers.

[0039] The preferred glass transition temperature (Tg) of the epoxy-modified acrylic emulsion is 10–15 °C. Within this Tg range, the emulsion exhibits good flexibility and excellent film-forming properties, which is beneficial for forming a flexible yet rigid emulsion film. The weather resistance of the emulsion film can be improved by adjusting the Tg of the epoxy-modified acrylic emulsion through the introduction of long-chain monomers.

[0040] The method for preparing epoxy-modified acrylic emulsion provided by this invention improves the weather resistance of the emulsion by rationally combining special hard monomers, soft monomers and functional monomers, adding long carbon chain monomers, and utilizing the good compatibility between the acrylate monomers attached to the epoxy resin segments and other acrylate monomers to improve the dispersibility and stability of the epoxy resin in the emulsion. This ensures that the epoxy resin is completely encapsulated by the emulsion system, which is conducive to the formation of a dense interpenetrating network structure and enhances the metal rust and corrosion prevention performance of the emulsion.

[0041] Another object of the present invention is to provide an application of the epoxy-modified acrylic emulsion as described above in metal rust and corrosion prevention.

[0042] The epoxy-modified acrylic emulsion provided by this invention, when coated onto the surface of a metal material, forms a protective film on the metal surface after the emulsion dries. The epoxy resin is fully encapsulated in the acrylic emulsion. Utilizing the excellent permeability and corrosion resistance of the specially modified epoxy resin, the density of the protective film can be improved, reducing the penetration of gas and moisture, thereby enhancing the salt spray resistance of the protective film. At the same time, the acrylic emulsion has excellent weather resistance and adhesion, enabling the protective film to simultaneously possess weather resistance, chemical corrosion resistance, and salt spray resistance, thus providing excellent protection for the metal material.

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0044] Unless otherwise specified, the acrylate epoxy phosphate resins in Preparation Examples 1-6 of this invention were prepared according to the following method: 76 parts by weight of solvent DMM and the amount of bisphenol A epoxy resin as specified in the formula were added to a flask equipped with a thermometer, stirrer and reflux condenser. The mixture was then heated to 100°C to dissolve the resin. After complete dissolution, 0.33 parts by weight of N,N-dimethylbenzylamine were added. The amount of acrylic acid as specified in the formula was added dropwise over 30 minutes. After the addition was completed, the temperature was slowly raised to the first reaction temperature and maintained for the first reaction time. The reaction was stopped when the acid value was less than 1. The temperature was then lowered to the second reaction temperature, and 12.25 parts by weight of 80% phosphoric acid was added to carry out the esterification reaction. The reaction was continued for the second reaction time to obtain acrylic epoxy phosphate resin.

[0045] The modified epoxy resin in Preparation Example 7 was prepared according to the following method: Add 76 parts by weight of solvent DMM and the amount of bisphenol A epoxy resin as specified in the formula to a flask equipped with a thermometer, stirrer and reflux condenser. Then heat to 100°C to dissolve. After complete dissolution, add 0.33 parts by weight of N,N-dimethylbenzylamine. Add the amount of acrylic acid as specified in the formula dropwise over 30 minutes. After the dropwise addition is completed, slowly raise the temperature to the first reaction temperature and continue to maintain the first reaction time. Stop the reaction when the acid value is less than 1 to obtain the modified epoxy resin.

[0046] The amounts of reactants added, reaction temperatures, reaction times, and the numbers of the acrylic epoxy phosphate resin and modified epoxy resin in each preparation example are shown in Table 1. Table 1 In Table 1, the amounts of epoxy resin and acrylic acid added are expressed in parts by weight; NPEL-127, NPEL-128, and NPEL-134 in Table 1 are liquid bisphenol A type epoxy resins manufactured by Nan Ya Epoxy Resin (Kunshan) Co., Ltd.; NPES-901, NPES-902, and NPES-903 are solid bisphenol A type epoxy resins manufactured by Nan Ya Epoxy Resin (Kunshan) Co., Ltd.

[0047] The preparation methods of the epoxy-modified acrylic emulsions in the embodiments and comparative examples of the present invention include the following steps: S1: According to the formula, add the emulsifier and deionized water to the emulsification kettle and stir evenly. Then add styrene, epoxy phosphate resin, methyl methacrylate, n-butyl methacrylate, isooctyl acrylate, methacrylic acid, acrylamide, and caprolactone-modified acrylate monomer M-5300 and stir evenly to form an emulsion, thus obtaining a pre-emulsion. S2: Dissolve 0.2 parts by weight of potassium persulfate in 2 parts by weight of deionized water to prepare the first initiator solution; S3: Dissolve 0.2 parts by weight of ammonium persulfate initiator in 10 parts by weight of deionized water to prepare the second initiator solution; S4: Add deionized water and emulsifier to the reaction vessel according to the formula, stir and heat to 75-85℃ to obtain the base liquid; S5: Add 10% of the total weight of the pre-emulsion to the base liquid. After adding the first initiator solution, keep it at 80℃ for 30 minutes for prepolymerization. Then, add the remaining pre-emulsion and the second initiator solution dropwise to the reactor simultaneously. The dropwise addition time is controlled at 200-240 minutes, and the reaction temperature is 75-85℃. After the dropwise addition is completed, cool the reactor. When the emulsion cools down to below 50℃, add ammonia and deionized water to the emulsion to adjust the pH value of the emulsion in the reactor to 7-8. Filter the emulsion to obtain the epoxy-modified acrylic emulsion.

[0048] The amount of raw materials added to the base liquid and pre-emulsion in each embodiment and comparative example is shown in Table 2. The amount of each component added is expressed in parts by weight. The difference between Comparative Example 1 and the embodiments is that no acrylic epoxy phosphate resin was added.

[0049] Table 2 It should be noted that no acrylic epoxy phosphate resin was introduced in Comparative Example 1, and no phosphoric acid was introduced during the preparation of the modified epoxy resin in Comparative Example 2; in Comparative Example 3, the epoxy resin was not modified and was directly introduced into the pre-emulsion.

[0050] Epoxy-modified acrylic emulsion was prepared using the above proportions and process conditions. The prepared epoxy-modified acrylic emulsion was then used to prepare coatings according to Table 3 for testing. All materials in Table 3 are expressed in parts by weight.

[0051] Table 3 serial number Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 lotion 50 50 50 50 50 50 50 50 50 Anti-flash rust agent 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Pigment 45 45 45 45 45 45 45 45 45 Neutralizing agent 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 TEG0207 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BCS 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 DB 2 2 2 2 2 2 2 2 2 0620 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 The testing method is as follows: Salt water resistance test and salt spray resistance test were performed in accordance with the standard ISO 9227-2006 Corrosion test in artificial atmosphere - Salt spray test.

[0052] Storage stability test procedure: Place each emulsion in a 50℃ oven for 30 days and observe the stability of the emulsion; where "○" indicates excellent; "△" indicates good; "×" indicates poor.

[0053] The flexibility properties of each emulsion were tested in accordance with the standard GB / T1731-2020.

[0054] Adhesion test method: Performed in accordance with standard GB 1720-79.

[0055] Hardness test method: Performed in accordance with standard GB / T 6739-2006.

[0056] The results are shown in Table 4.

[0057] Table 4 serial number Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 flexibility 1mm 1mm 1mm 1mm 1mm 1mm 1mm 1mm 1mm Adhesion Level 0 Level 0 Level 0 Level 0 Level 0 Level 0 Level 0 Level 0 Level 0 hardness H H H 2H 3H 3H H 2H 2H Salt spray / h 210 230 250 320 280 280 200 270 220 thermal storage ○ ○ ○ ○ △ × ○ △ × in, Figure 1 The particle size distribution is shown in Example 4 for the epoxy-modified acrylic emulsion.

[0058] In summary, this invention improves the weather resistance of emulsions by rationally combining special hard monomers, soft monomers, and functional monomers, adding long-chain monomers, effectively controlling the particle size of the emulsion through prepolymerization, and enhancing the stability of the emulsion system. Furthermore, the invention utilizes the compounding of specific emulsifiers and leverages the similarity and compatibility between the structure of the acrylic acid-modified epoxy acrylate phosphate and the acrylic polymer structure to improve the dispersibility and stability of epoxy resin in the emulsion, ensuring that the epoxy resin is completely encapsulated by the emulsion system. This facilitates the formation of a dense interpenetrating network structure and enhances the metal rust and corrosion resistance of the emulsion.

[0059] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An epoxy-modified acrylic emulsion, characterized in that, The raw materials comprise the following components by weight: 30-40 parts styrene; 1-10 parts of acrylic epoxy phosphate resin; 10-20 parts of methyl methacrylate; 5-10 parts of n-butyl methacrylate; 30-35 parts of isooctyl acrylate; 2-5 parts methacrylic acid; Acrylamide 2-5 parts; 1-3 parts of caprolactone-modified acrylate monomer; 5-8 parts emulsifier; Initiator 0.3-0.6 parts; 80-150 parts of deionized water.

2. The epoxy-modified acrylic emulsion as described in claim 1, characterized in that, The preparation method of the acrylic epoxy phosphate resin is as follows: add epoxy resin to a solvent, heat to 100°C to dissolve, add N,N-dimethylbenzylamine, and then add acrylic acid dropwise; after the dropwise addition is completed, heat to 105-125°C to react; after the reaction is completed, cool to 70°C, add phosphoric acid to carry out esterification reaction, and obtain acrylic epoxy phosphate resin.

3. The epoxy-modified acrylic emulsion as described in claim 2, characterized in that, The epoxy resin is a bisphenol A type epoxy resin.

4. The epoxy-modified acrylic emulsion as described in claim 2, characterized in that, The solvent is dipropylene glycol dimethyl ether.

5. The epoxy-modified acrylic emulsion as described in claim 2, characterized in that, The mass ratio of the epoxy resin, the solvent, the N,N dimethyl benzylamine, the acrylic acid, and the phosphoric acid is (150-750):(70-280):0.33:(30-80):(8-15).

6. The epoxy-modified acrylic emulsion according to any one of claims 1-5, characterized in that, The emulsifier is selected from at least one of reactive anionic emulsifiers and reactive nonionic emulsifiers.

7. The epoxy-modified acrylic emulsion as described in claim 6, characterized in that, The reactive anionic emulsifier is selected from at least one of allyloxy polyoxyethylene ether ammonium sulfate and allyloxy polyoxyethylene ether phosphate; the reactive nonionic emulsifier is allyloxy polyoxyethylene ether.

8. The epoxy-modified acrylic emulsion according to any one of claims 1-5, characterized in that, The initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate.

9. A method for preparing an epoxy-modified acrylic emulsion as described in any one of claims 1-8, characterized in that, Includes the following steps: S1: By weight, mix 2-5 parts of emulsifier with 25 parts of deionized water, then add 30-40 parts of styrene, 1-10 parts of epoxy phosphate acrylate resin, 10-20 parts of methyl methacrylate, 5-10 parts of n-butyl methacrylate, 30-35 parts of isooctyl acrylate, 2-5 parts of methacrylic acid, 2-5 parts of acrylamide, and 1-3 parts of caprolactone-modified acrylate monomer, and stir to form a pre-emulsion. S2: Dissolve 0.1-0.2 parts of the initiator in 2 parts of deionized water to obtain the first initiator solution; S3: Dissolve the remaining initiator in 10 parts of deionized water to obtain the second initiator solution; S4: Mix 85 parts of deionized water and the remaining emulsifier, heat, and obtain the base liquid; S5: After adding a portion of pre-emulsion to the base liquid, add the first initiator solution and react at 75-85℃ to obtain a reaction solution; S6: Add the remaining pre-emulsion and the second initiator solution to the reaction solution, and react at 75-85℃ to obtain an epoxy-modified acrylic emulsion.

10. The application of the epoxy-modified acrylic emulsion as described in any one of claims 1-8 in metal rust and corrosion prevention.

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