Acrylate modified polyvinyl acetate emulsion and preparation method thereof

Abstract

The invention discloses an acrylate modified polyvinyl acetate emulsion and a preparation method thereof. The emulsion comprises the following raw materials by mass: 15-40 parts of a protective colloid; 2 to 10 parts of a nonionic emulsifier; 2-10 parts of an anionic emulsifier; 0.5 to 2 parts of a buffering agent; 300 to 600 parts of a mixed monomer; 1 to 10 parts of a crosslinking monomer; 5 to 10 parts of an initiator; and 300 to 600 parts of water. According to the acrylate-modified polyvinyl acetate emulsion, the acrylate-modified monomer and the crosslinking monomer are introduced, so that polymer molecules form a three-dimensional network structure connected by covalent bonds, and compared with unmodified polyvinyl acetate emulsion, the acrylate-modified polyvinyl acetate emulsion has higher bonding strength and higher solvent resistance. According to the preparation method, a novel initiator system with low-temperature activity is introduced, compared with an existing traditional synthesis method, operation is easy, continuous dropwise adding of a reaction monomer and an initiator is not needed, the reaction temperature is lower than the boiling point of a vinyl acetate monomer, safety is high, energy consumption is low, and industrial production is facilitated.

Description

Technical Field

[0001] This application belongs to the field of polymer emulsion polymerization technology, specifically relating to an acrylate-modified polyvinyl acetate emulsion and its preparation method. Background Technology

[0002] Polyvinyl acetate (PVAc) is an important polymer with the chemical formula (C4H6O2). n PVAc typically has a molecular weight ranging from tens of thousands to hundreds of thousands. At room temperature, PVAc appears as pale yellow, transparent, glassy granules or a white, viscous liquid, characterized by its odorless and tasteless nature and strong adhesive properties. These properties make it widely used in coatings, adhesives, and fiber treatment. From a molecular structure perspective, the acetate groups on the PVAc molecular chain give it polar characteristics, enabling it to form strong intermolecular forces with the surface of glass fibers. This characteristic forms the theoretical basis for its application in glass fiber composites. However, PVAc also has some drawbacks affecting its production and application. For example, the typical synthesis method of PVAc requires high temperatures, close to the boiling point of vinyl acetate monomer, and the monomer and initiator need to be added slowly, making the operation cumbersome. Furthermore, a significant portion of the products made from PVAc are used in various solvent-contact applications, and PVAc has poor solvent resistance.

[0003] To improve the adhesion, solvent resistance, and other properties of PVAc and simplify its preparation method, researchers have enhanced its application performance by copolymerizing vinyl acetate monomer with other substances or blending PVAc emulsions with other substances. Chinese patent application CN111876099A discloses a method for synthesizing a formaldehyde-free, highly water-resistant PVAc adhesive by first introducing copolymerization modification of acrylate and vinyl acetate via semi-continuous emulsion polymerization, and then mechanically blending the resulting latex with an aqueous crosslinking agent, a cationic modifier, and a thickener. This method employs the traditional semi-continuous emulsion polymerization method for PVAc synthesis, which involves numerous and cumbersome steps, requiring a reaction temperature of 70-80°C. oThe high reaction temperature of C is unfavorable for continuous industrial production. Chinese patent application CN103131354A discloses a method using a staged polymerization process, first synthesizing a polyvinyl acetate polymer seed, then introducing monomers such as styrene and acrylates to polymerize within the polymer seed, thus synthesizing a styrene-modified polyvinyl acetate emulsion. This method requires first synthesizing the polymer seed by slowly adding reactants and initiators at a high temperature, then slowly adding modified monomers and initiators at the same high temperature, synthesizing the emulsion step by step. This reaction is cumbersome, involves high temperatures, and has many variables, making it unsuitable for continuous industrial production. Chinese patent application CN112322230A discloses a method for preparing modified polyvinyl alcohol as a protective colloid using acetal modification, and then copolymerizing vinyl acetate by introducing ethylene tert-carbonate to prepare a polyvinyl acetate emulsion with high water resistance. This method requires slowly adding reactants and initiators in multiple batches, with a reaction temperature of 75-85°C. o C, higher than the boiling point of the reactant monomer vinyl acetate (72.5). o C), the preparation process is complicated, the reaction temperature is high, and the energy consumption is large.

[0004] Therefore, developing a modified PVAc emulsion with high adhesion and high solvent resistance that is easy to prepare and can be reacted at low temperatures has important practical significance and application prospects. Summary of the Invention

[0005] The main purpose of this application is to solve the problems of low bonding strength, poor solvent resistance, and numerous and cumbersome preparation processes of existing polyvinyl acetate emulsions, which require a high reaction temperature above the boiling point of vinyl acetate monomers. The application provides an acrylate-modified PVAc emulsion and its preparation method that can react at low temperatures, does not require continuous addition of reactants and initiators, has strong bonding properties, and excellent solvent resistance.

[0006] To achieve the above objectives, this application adopts the following technical solution: According to a first aspect of this application, an acrylate-modified polyvinyl acetate emulsion is provided, the emulsion comprising the following raw materials in parts by weight: Protective colloid: 15-40 parts; nonionic emulsifier: 2-10 parts; anionic emulsifier: 2-10 parts; buffer: 0.5-2 parts; mixed monomers: 300-600 parts; crosslinking monomers: 1-10 parts; initiator: 5-10 parts; water: 300-600 parts.

[0007] Preferably, the composition is as follows: protective colloid: 25-35 parts; nonionic emulsifier: 5-9 parts; anionic emulsifier: 5-9 parts; buffer: 1-2 parts; mixed monomers: 400-500 parts; crosslinking monomers: 1-8 parts; initiator: 5-9 parts; water: 350-500 parts.

[0008] The total amount of the mixed monomers is 100%, with vinyl acetate comprising 75%-95% and acrylate comprising 5%-25%. Controlling both within these ranges is primarily due to the different polymerization rates of vinyl acetate and acrylate, and the fact that vinyl acetate is highly hydrophilic while acrylate is highly lipophilic. Excessive acrylate can easily affect reaction stability, increase the risk of demulsification and gelation, and also lead to higher production costs; conversely, if the proportion of acrylate is too low, the modification effect is poor. Preferably, the mixed monomers comprise 85%-90% vinyl acetate and 10-15% acrylate.

[0009] The acrylate is one or more selected from methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and methyl methacrylate. Alkyl acrylates (methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate) act as soft monomers, lowering the glass transition temperature (Tg) of the product and allowing them to intercalate between polyvinyl acetate molecular chains, facilitating polymer chain movement and improving product flexibility; however, excessive use can reduce the product's oil resistance. Methyl methacrylate, as a hard monomer, has a high homopolymer Tg; using it as a modifying monomer can improve the product's hardness and heat resistance, but excessive use can increase the product's Tg. In the specific reaction, selecting appropriate proportions of soft and hard monomers can obtain a product that meets the requirements and ensure reaction stability. In some specific embodiments, the acrylate is at least one selected from methyl methacrylate and isooctyl acrylate.

[0010] The protective colloid is one or more of polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and polyvinylpyrrolidone.

[0011] The polyvinyl alcohol is one or more of the types 1788, 1792, and 1799.

[0012] The nonionic emulsifier is one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and fatty acid polyoxyethylene ester.

[0013] The anionic emulsifier is one or more of sodium lauryl ether sulfate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, allyl polyether sulfate, sodium dioctyl succinate sulfonate, and sodium alkylphenol polyether sulfosuccinate.

[0014] The buffer is one or more of sodium bicarbonate, sodium carbonate, potassium dihydrogen phosphate, and disodium hydrogen phosphate.

[0015] The crosslinking monomer is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, N-hydroxymethylacrylamide, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and glycidyl methacrylate. The emulsion of this application introduces crosslinking monomers into the raw materials, which can introduce active groups such as hydroxyl, carboxyl, and epoxy groups into the product molecules, providing more crosslinking reaction sites and improving the product's hardness, solvent resistance, and abrasion resistance. Preferably, after modification with a crosslinking monomer containing hydroxyl groups, the side hydroxyl groups provided by the crosslinking monomer allow the product to react with the added crosslinking agent after film formation, forming a robust crosslinking network, significantly improving the product's hardness, solvent resistance, abrasion resistance, and adhesion. However, the amount of crosslinking monomer used in the reaction needs to be strictly controlled. If the amount is too high, it will increase the risk of gelation in the reaction and may also increase the product's Tg. Excessive unreacted hydrophilic groups will make the product prone to bubbling and generating more surface defects during film formation. Therefore, this application limits the amount of crosslinking monomer to 1-10 parts, which can ensure the improvement of subsequent product performance while avoiding adverse effects on the reaction and product surface. In some specific implementation schemes, the amount of crosslinking monomer used is 1-8 parts.

[0016] The initiator is a bis(4) A mixture of one or more of the following in any proportion: tert-butylcyclohexyl peroxide, tert-butyl peroxyneodecanate, azobisisobutyronitrile, azobisisoheptanenitrile, azodimethoxyisoheptanenitrile, and diisobutyryl peroxide. Preferably, the initiator is bis(4-)-butyl peroxide, which is more conducive to the reaction. The initiator is selected from tert-butylcyclohexyl peroxide, azodimethoxyisoheptanenitrile, and diisobutyryl peroxide; it exhibits higher activity and faster initiation rate at low temperatures. Experiments have shown that if the amount of initiator is too small, the reactants may not react completely or may even fail to initiate the reaction; while if the amount of initiator is too large, the reaction rate will be too fast, the reaction process will be difficult to control, and the latex particles will easily aggregate or even gel. Therefore, the amount of initiator in this application is limited to 5-10 parts. In some specific embodiments, the amount of initiator is 5-8 parts.

[0017] The acrylate-modified polyvinyl acetate emulsion of this application introduces both acrylate-modified monomers and crosslinking monomers. By rationally controlling the type and amount of each raw material, the resulting polymer molecules have a three-dimensional network structure connected by covalent bonds, thereby possessing higher bonding strength and solvent resistance.

[0018] According to a second aspect of this application, a method for preparing the aforementioned acrylate-modified polyvinyl acetate emulsion is provided, comprising the following steps: S1: Mix water and protective colloid, then heat to 75-95°C. o C was completely dissolved, then the temperature was lowered to 50-60°C. o C. Add anionic emulsifier, nonionic emulsifier, and buffer, stir well, and then cool to room temperature to obtain an aqueous solution. S2: Mix the mixed monomers, crosslinking monomers and initiators evenly to form an oil phase solution; S3: Add the aqueous solution and the oil solution to the reaction vessel and mix and stir evenly to obtain a vinyl acetate emulsion; S4: Raise the temperature of the material in the reactor to 30-50°C. o C, react under mechanical stirring for 5-8 hours; S5: The temperature of the material in the reactor is reduced to room temperature to obtain the acrylate-modified polyvinyl acetate emulsion.

[0019] The room temperature is 20-30℃.

[0020] Compared with existing technologies, the method for preparing acrylate-modified polyvinyl acetate emulsion described in this application introduces a novel low-temperature active initiator system. This eliminates the need for continuous dropwise addition of reactants and initiators during the reaction, and also eliminates the need to heat to the boiling point of the vinyl acetate monomer (72.5°C). o At temperatures above C), the reaction operation is simple, safe, and energy-saving; the PVAc latex particles obtained are modified by introducing acrylate-modified monomers and crosslinking monomers, which enable the polymer molecules to form a three-dimensional network structure connected by covalent bonds, which is different from the common chain structure, thus greatly improving the bonding strength and solvent resistance of the modified PVAc emulsion. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0022] In some alternative embodiments, an acrylate-modified polyvinyl acetate emulsion is provided, comprising the following parts by weight of raw materials: Protective colloid: 15-40 parts; nonionic emulsifier: 2-10 parts; anionic emulsifier: 2-10 parts; buffer: 0.5-2 parts; mixed monomers: 300-600 parts; crosslinking monomers: 1-10 parts; initiator: 5-10 parts; water: 300-600 parts.

[0023] In a preferred embodiment, the protective colloid is 25-35 parts; the nonionic emulsifier is 5-9 parts; the anionic emulsifier is 5-9 parts; the buffer is 1-2 parts; the mixed monomers are 400-500 parts; the crosslinking monomers are 1-8 parts; the initiator is 5-9 parts; and the water is 350-500 parts.

[0024] In some optional embodiments, the total amount of the mixed monomers, calculated as 100%, comprises 75%-95% vinyl acetate and 5%-25% acrylate. In a preferred embodiment, the mixed monomers comprise 85%-90% vinyl acetate and 10-15% acrylate. The crosslinking monomer is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, N-hydroxymethylacrylamide, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and glycidyl methacrylate.

[0025] In some alternative embodiments, the acrylate is one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and methyl methacrylate.

[0026] In some alternative embodiments, the protective colloid is one or more of polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and polyvinylpyrrolidone. The polyvinyl alcohol is one or more of type 1788, type 1792, and type 1799.

[0027] In some alternative embodiments, the nonionic emulsifier is one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and fatty acid polyoxyethylene ester.

[0028] In some optional embodiments, the anionic emulsifier is one or more of sodium lauryl ether sulfate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfonate, allyl polyether sulfate, sodium dioctyl succinate sulfonate, and sodium alkylphenol polyether sulfosuccinate.

[0029] In some alternative embodiments, the buffer is one or more of sodium bicarbonate, sodium carbonate, potassium dihydrogen phosphate, and disodium hydrogen phosphate. The water is deionized water.

[0030] In some alternative embodiments, the initiator is bis(4) A mixture of one or more of the following in any proportion: tert-butylcyclohexyl peroxide, tert-butyl peroxyneodecanate, azobisisobutyronitrile, azobisisoheptanenitrile, azobismethoxyisoheptanenitrile, and diisobutyryl peroxide.

[0031] In some optional embodiments, a method for preparing an acrylate-modified polyvinyl acetate emulsion is provided, comprising the following steps: S1: Mix water and protective colloid, then heat to 75-95°C. o C was completely dissolved, then the temperature was lowered to 50-60°C. o C. Add anionic emulsifier, nonionic emulsifier, and buffer, stir well, and then cool to room temperature to obtain an aqueous solution. S2: Mix the mixed monomers, crosslinking monomers and initiators evenly to form an oil phase solution; S3: Add the aqueous solution and the oil solution to the reaction vessel and mix and stir evenly to obtain a vinyl acetate emulsion; S4: Raise the temperature of the material in the reactor to 30-50°C. o C, react under mechanical stirring for 5-8 hours; S5: Cool the material temperature in the reactor to room temperature to obtain an acrylate-modified polyvinyl acetate emulsion.

[0032] In some alternative implementations, the mechanical stirring speed is 200-300 rpm.

[0033] To more clearly explain the technical solution of this application, specific implementation examples of the raw material formulation and preparation method of the acrylate-modified polyvinyl acetate emulsion of this application are listed. See Table 1 for details.

[0034] Table 1 Specific Implementation Examples

[0035] To more clearly explain the technical solution of this application, the raw material formulation and preparation method process parameters of the acrylate-modified polyvinyl acetate emulsion of this application are listed exemplarily. See Table 2 for details.

[0036] It should be noted that the specific types, contents, and combinations of the components selected in Table 2 do not limit the scope of protection of this application.

[0037] Table 2 Raw material formulations and process parameters of the emulsions in Examples 1-8

[0038] Comparative test cases To further illustrate the beneficial effects of this application, unmodified PVAc emulsion and modified PVAc emulsions with different formulation ratios were selected as comparative examples 1-2 for synthesis and performance comparison tests.

[0039] Comparative Example 1: The unmodified PVAc emulsion was synthesized and tested using the same method as in Example 1. The raw material composition was as follows: 480g deionized water, 20g polyvinyl alcohol, 15g polyvinylpyrrolidone (PVP-K30), 8g sodium dodecylbenzenesulfonate (SDBS), 8g alkylphenol polyoxyethylene ether (OP-10), 1g buffer, 460g vinyl acetate monomer, 5g hydroxyethyl methacrylate, and bis(4-ethylhexyl) initiator. 5g of tert-butylcyclohexyl peroxide dicarbonate.

[0040] Polymerization reaction temperature 40 o C, stirring speed 250 rpm, reaction time 5 h.

[0041] Comparative Example 2: The modified PVAc emulsion was synthesized and tested using the same method as in Example 1. The raw material composition was as follows: 480g deionized water, 20g polyvinyl alcohol, 15g polyvinylpyrrolidone (PVP-K30), 8g sodium dodecylbenzenesulfonate (SDBS), 8g alkylphenol polyoxyethylene ether (OP-10), 1g buffer, 350g vinyl acetate monomer, 120g methyl methacrylate, 12g hydroxyethyl methacrylate, and bis(4-dimethyl)phenol initiator. 5g of tert-butylcyclohexyl peroxide dicarbonate.

[0042] The products of the above embodiments and comparative examples were characterized.

[0043] B1: The reaction conversion rate (Conv.%) of the PVAc emulsion was calculated using the differential gravity method. The calculation formula is as follows:

[0044] In the formula: m2 is the mass of polyvinyl acetate obtained after vacuum drying of the emulsion sample during the polymerization reaction, m1 is the mass of the sampled emulsion, a is the mass of vinyl acetate monomer, acrylate monomer and hydroxyethyl methacrylate added to the formulation, and b is the mass of the aqueous phase added to the formulation.

[0045] B2: Determination of latex particle size in PVAc emulsions The prepared PVAc emulsion was diluted 100 times with deionized water and then subjected to particle size analysis using a Malvern Mastersize 3000 particle size analyzer.

[0046] B3: Determination of the adhesive properties of PVAc emulsions The prepared PVAc emulsion was diluted with deionized water to a solid content of 5% and stored in a spray bottle for later use. 20g of chopped glass fiber from Jushi Group Co., Ltd. was spread in a 20mm x 30mm uniform thickness as a glass fiber mat. 16g of diluted PVAc emulsion was then evenly sprayed onto the glass fiber mat using a spray bottle. The glass fiber mat sprayed with PVAc emulsion was then placed at 160°C. o After being dried in a constant temperature drying oven of EM-9240AS model by C-Xiehao (Shanghai) Instrument Technology Co., Ltd. for 15 minutes, the fiberglass mat was removed and cooled to obtain a fiberglass mat bonded with PVAc emulsion. The tensile strength of the fiberglass mat was then tested by an ED22.203 type tensile testing machine of Shanghai Yi Test Equipment Co., Ltd.

[0047] B4: Solvent resistance test of PVAc emulsion Take 4g of PVAc emulsion and place it in a 130°C container. o The PVAc emulsion was dried and weighed in an EM-9240AS constant temperature drying oven manufactured by C-Xiehao (Shanghai) Instrument Technology Co., Ltd. for 3 hours. The dried PVAc emulsion solids were then packaged into cloth tea bags and weighed. The tea bags were then placed in boiling acetone and boiled for 3 hours. After boiling, the tea bags were removed, dried, and weighed. The acetone solubility (a%) of the PVAc emulsion solids was calculated using the following formula:

[0048] In the formula: m0 is the mass of the dried PVAc emulsion solids placed in the cloth tea bag, m1 is the mass of the cloth tea bag after being placed in the dried PVAc emulsion solids, and m2 is the mass of the cloth tea bag after being boiled in acetone and dried.

[0049] The performance test data of the acrylate-modified PVAc emulsion obtained from the above synthesis reaction are shown in Table 3.

[0050] Table 3 Performance test results for each embodiment and comparative example

[0051] Table 3 (continued) Performance test results of each embodiment and comparative example

[0052] As can be seen from the above test comparisons, the acrylate-modified polyvinyl acetate emulsions of the embodiments of this application have a higher reaction conversion rate and better adhesion and solvent resistance compared to the comparative example.

[0053] In summary, the acrylate-modified polyvinyl acetate emulsion of this application, by introducing acrylate-modifying monomers and crosslinking monomers, enables the polymer molecules to form a three-dimensional network structure linked by covalent bonds, resulting in higher bonding strength and stronger solvent resistance. This preparation method, through the introduction of a novel low-temperature active initiator system, is simpler to operate than existing traditional synthesis methods, does not require continuous dropwise addition of reactants and initiators, and operates at a reaction temperature below the boiling point of vinyl acetate monomer, thus offering high safety, low energy consumption, and being conducive to industrial production.

[0054] Finally, it should be noted that in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An acrylate-modified polyvinyl acetate emulsion, characterized in that, The emulsion comprises raw materials in the following mass fractions: protective colloid: 15-40 parts; non-ionic emulsifier: 2-10 parts; anionic emulsifier: 2-10 parts; buffer: 0.5-2 parts; mixed monomer: 300-600 parts; crosslinking monomer: 1-10 parts; initiator: 5-10 parts; water: 300-600 parts.

2. The acrylate-modified polyvinyl acetate emulsion according to claim 1, characterized in that, The total amount of the mixed monomer is 100%, and the amount of vinyl acetate is 75%-95%, and the amount of acrylate is 5%-25%.

3. The acrylate-modified polyvinyl acetate emulsion according to claim 1 or 2, characterized in that, The acrylate is one or more of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, pentyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, and methyl methacrylate.

4. The acrylate-modified polyvinyl acetate emulsion of claim 1, wherein, The protective colloid is one or more of polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and polyvinylpyrrolidone.

5. The acrylate-modified polyvinyl acetate emulsion of claim 4, wherein the polyvinyl acetate is present in an amount of 20 to 80 wt.%, based on the total weight of the acrylate-modified polyvinyl acetate emulsion. The polyvinyl alcohol is one or more of types 1788, 1792, and 1799.

6. The acrylate-modified polyvinyl acetate emulsion of claim 1, wherein, The non-ionic emulsifier is one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and fatty acid polyoxyethylene ester.

7. The acrylate-modified polyvinyl acetate emulsion of claim 1, wherein the polyvinyl acetate is present in an amount of 20 to 80 wt. % based on the total weight of the emulsion. The anionic emulsifier is one or more of sodium lauryl polyether sulfate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecylsulfonate, allyl polyether sulfate, dioctyl sodium sulfosuccinate, and sodium alkylphenol polyether sulfosuccinate.

8. The acrylate-modified polyvinyl acetate emulsion of claim 1, wherein, The buffer is one or more of sodium bicarbonate, sodium carbonate, potassium dihydrogen phosphate, and disodium hydrogen phosphate.

9. The acrylate-modified polyvinyl acetate emulsion of claim 1, wherein, The crosslinking monomer is one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, acrylamide, N-hydroxymethyl acrylamide, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and glycidyl methacrylate.

10. The acrylate-modified polyvinyl acetate emulsion of claim 1, wherein, The initiator is one or more of bis(4 tert-butyl cyclohexyl) peroxydicarbonate, t-butyl peroxyneodecanoate, azobisisobutyronitrile, azobisisoheptyl nitrile, azobis-methoxyisoheptyl nitrile, diisobutyryl peroxide in any ratio mixture.

11. A process for preparing an acrylate-modified polyvinyl acetate emulsion as claimed in any one of claims 1 to 10, characterized in that, The preparation steps are as follows: S1: water, protective colloid are mixed and heated to 75-95 o C, then cooled to 50-60 o C, anionic emulsifier, non-ionic emulsifier, buffer are added, stirred uniformly and cooled to room temperature as an aqueous solution; S2: Mix the mixed monomer, crosslinking monomer, and initiator uniformly as an oil phase solution; S3: Mix and stir the aqueous phase solution and the oil phase solution in the reaction kettle uniformly to obtain a vinyl acetate emulsion; S4: The temperature of the reactor is raised to 30-50 o C, under mechanical stirring for 5-8 h; S5: Reduce the temperature of the reaction kettle to room temperature to obtain the acrylate-modified polyvinyl acetate emulsion.

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