A waterproof and oil-resistant acrylic emulsion, its preparation method and application

Abstract

This invention discloses a waterproof and oil-resistant acrylic emulsion, its preparation method, and its application. The raw materials for the emulsion include monomers, crosslinking agents, initiators, emulsifiers, molecular weight regulators, preservatives, defoamers, neutralizing agents, and pure water. The monomers include methyl methacrylate, polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate, isooctyl acrylate, diacetone acrylamide, and methacrylic acid. This waterproof and oil-resistant acrylic emulsion, as a water-based barrier coating, can be applied to various packaging papers to form a coating similar to a PE film. This coating exhibits outstanding waterproof and oil-resistant barrier properties, excellent anti-tack and folding endurance, and the coated paper can be recycled, replacing PE-coated paper which is difficult to recycle. Furthermore, this waterproof and oil-resistant acrylic emulsion meets food-grade requirements and can be used in food packaging paper.

Description

Technical Field

[0001] This invention relates to the field of acrylic emulsion technology, specifically to a waterproof and oil-resistant acrylic emulsion, its preparation method, and its application. Background Technology

[0002] Waterproof and oil-resistant acrylic emulsion is a water-based environmentally friendly coating based on acrylic copolymers and modified with special monomers, which can simultaneously provide water and oil resistance. It provides the packaging paper industry with a high-performance and environmentally friendly functional coating. Especially in the food packaging field, it offers a relatively environmentally friendly and efficient solution to replace traditional plastic coatings and fluorinated oil-resistant agents.

[0003] Pure acrylic emulsions are generally high-molecular polymer emulsions made from acrylic acid, methacrylic acid, and acrylate monomers (such as methyl acrylate, ethyl acrylate, butyl acrylate, etc.) through emulsion polymerization. They are characterized by good film-forming properties, high transparency, good weather resistance, and being environmentally friendly and non-toxic. The waterproof and oil-repellent functions are achieved through molecular design. During the polymerization process, hydrophobic monomers (such as styrene and long-chain acrylates) are introduced to provide water repellency and prevent liquid water penetration. At the same time, oleophobic monomers, such as fluorinated monomers (PFOA, PFOS), are introduced. However, due to environmental and health issues, these have been gradually phased out. Modern pure acrylic systems usually use fluorine-free oleophobic monomers (such as long-branched acrylate polymers, silicone-modified acrylates, etc.) to provide oil repellency.

[0004] However, while existing waterproof and oil-resistant pure acrylic emulsions possess certain waterproof and oil-resistant properties, their application on packaging paper often results in poor performance due to insufficient anti-tack and folding endurance. A detailed analysis follows:

[0005] Anti-tack properties are crucial for several factors. Firstly, manufacturing processes require coated paper to be rolled into large rolls or stacked together for storage and transport. If the coating is sticky, the rolls or stacks will clump together and cannot be easily separated. Secondly, storage environments present challenges. Paper may be stored in environments with large temperature fluctuations and high humidity. High temperatures and humidity intensify the movement of polymer molecular chains, causing the coating to soften and become sticky, making it more prone to re-tack. Poor anti-tack properties can lead to a series of problems, including difficulty in unwinding, surface damage, printing and color matching issues, and ultimately, the scrapping of finished products.

[0006] Folding endurance is essential for packaging, as most paper packaging requires folding, creasing, and slotting to become boxes, bags, bowls, etc. It also depends on usage conditions; consumers squeezing takeout bags and products being jostled during transport cause the paper to bend and fold. Poor folding endurance can lead to a range of problems, including coating cracking, loss of waterproof and oil-resistant properties, and cosmetic damage.

[0007] Therefore, we urgently need to optimize and improve the composition and process of existing waterproof and oil-resistant acrylic emulsions to enhance their anti-tack and folding resistance. Summary of the Invention

[0008] The purpose of this invention is to provide a waterproof and oil-resistant acrylic emulsion, its preparation method, and its application, which solves the problem of poor anti-tack and folding resistance of existing waterproof and oil-resistant acrylic emulsions.

[0009] The present invention achieves the above objectives through the following technical solutions:

[0010] A waterproof and oil-resistant acrylic emulsion, wherein the raw materials of the emulsion include monomers, crosslinking agents, initiators, emulsifiers, molecular weight regulators, preservatives, defoamers, neutralizers, and pure water;

[0011] The monomers include methyl methacrylate, polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate, isooctyl acrylate, diacetone acrylamide, and methacrylic acid.

[0012] Further improvements are made in the following aspects:

[0013] The crosslinking agent is adipate dihydrazide;

[0014] The initiator includes ammonium persulfate, tert-butyl hydroperoxide, and sodium ascorbate;

[0015] The emulsifiers include sodium dodecylbenzenesulfonate and sodium allyloxyalkyl polyoxyethylene ether sulfate;

[0016] The molecular weight regulator is n-dodecyl mercaptan;

[0017] The preservative used is potassium sorbate;

[0018] The defoamer used is a white oil defoamer;

[0019] The neutralizing agent is ammonia.

[0020] A further improvement is that, by weight, the raw materials of the emulsion include: 10-20 parts methyl methacrylate, 2-8 parts polyethylene glycol diacrylate, 2-8 parts butyl methacrylate, 2-5 parts tert-butyl methacrylate, 2-10 parts butyl acrylate, 3-10 parts isooctyl acrylate, 0.8-1.5 parts diacetone acrylamide, 1.0-2.0 parts methacrylic acid, 0.03-0.08 parts n-dodecyl mercaptan, and 0.0 2-0.06 parts sodium dodecylbenzenesulfonate, 0.05-0.1 parts sodium allyl oxyalkyl polyoxyethylene ether sulfate, 0.1-0.3 parts potassium sorbate, 0.4-0.8 parts adipic acid dihydrazide, 0.02-0.06 parts ammonium persulfate, 0.01-0.05 parts tert-butyl hydroperoxide, 0.01-0.05 parts sodium ascorbate, 0.1-0.3 parts white oil defoamer, 1.0-2.0 parts ammonia water, and 57-62 parts pure water.

[0021] This invention also provides a method for preparing a waterproof and oil-resistant acrylate emulsion, the method comprising the following steps:

[0022] S1. Add 35-45% pure water by mass to the reactor, start stirring, add 25-35% sodium dodecylbenzenesulfonate by mass, disperse for 5-10 minutes, seal the reactor, heat to 84-86℃, then evacuate and break the vacuum with nitrogen.

[0023] S2. Add 10-15% pure water by mass to the high-level tank stirred vessel, start stirring at a rate of 60-80 r / min, add the remaining sodium dodecylbenzenesulfonate and sodium allyloxypolyoxyethylene ether sulfate, and stir at a rate of 100-120 r / min for 8-12 min. Then add 40-60% by mass of diacetone acrylamide, methacrylic acid and methyl methacrylate, and 10-90% by mass of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate. Then add n-dodecyl mercaptan. After the addition is complete, stir for 30-40 min to obtain the high-level tank emulsion for later use.

[0024] S3. When the internal temperature of the reactor is 78-81℃, add 4-8% of the high-level tank emulsion by mass. After 2-4 minutes, add 30-35% of the ammonium persulfate by mass. Raise the temperature to 84-86℃ and keep it at that temperature for 8-12 minutes. Then, add the remaining high-level tank emulsion and the remaining ammonium persulfate dropwise over 0.9-1.1 hours and 1.2-1.3 hours, respectively. During the dropwise addition, control the temperature at 84-86℃. After the ammonium persulfate is added, continue to keep it at that temperature for 0.4-0.6 hours. Then, lower the temperature to 78-82℃ and adjust the pH to 8.5±0.2 using ammonia water. Keep it at that temperature until the material inside the reactor becomes a semi-transparent liquid.

[0025] S4. Add all the remaining monomer to the high-level tank and stir until completely dissolved and homogeneous to obtain the high-level tank monomer solution for later use.

[0026] S5. When the reactor temperature drops to 63-65℃, add 30-35% of the high-level tank monomer solution and stir for 13-17 minutes. When the temperature inside the reactor is 55-60℃, add 10-15% of tert-butyl hydroperoxide. After the addition is completed for 1.5-2.5 minutes, add 10-15% of sodium ascorbate for 4-5 minutes. After the temperature inside the reactor reaches the highest temperature, keep it at that temperature for 18-22 minutes.

[0027] S6. Repeat step S5 twice, adding 30-35% of the high-level tank monomer solution by mass and the remaining high-level tank monomer solution respectively to carry out the reaction.

[0028] S7. Wait for the temperature inside the reactor to drop to 64-66℃, and then add the remaining tert-butyl hydrogen peroxide and sodium ascorbate dropwise over a period of 50-70 minutes.

[0029] S8. After the temperature inside the reactor drops to 44-46℃, add adipic acid dihydrazide, followed by white oil defoamer and potassium sorbate. Adjust the solid content to 38-43%, filter and discharge to obtain waterproof and oil-proof acrylic emulsion.

[0030] The ammonium persulfate, tert-butyl hydroperoxide, and sodium ascorbate are all added in the form of an aqueous solution of the remaining pure water.

[0031] A further improvement is that, in step S8, after filtration, 4-6% of triethyl acetylglucose microcapsules with chitosan as the wall material are uniformly incorporated into the emulsion.

[0032] This invention also provides an application of the aforementioned waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper. The specific steps of the application are as follows: take packaging base paper, fix it on a coating machine, and apply the aforementioned waterproof and oil-resistant acrylic emulsion to the packaging base paper, with a coating amount of 2-8 g / m². 2 After coating, the coated paper is dried in an oven at 50-60℃ for 18-22 minutes, and then the coated paper is removed and placed in an indoor environment to stand for 18-36 hours to obtain the packaging paper.

[0033] This invention also provides another application of the aforementioned waterproof and oil-resistant acrylate emulsion in the preparation of packaging paper. The specific steps of this application are as follows: take the base packaging paper, fix it on a coating machine, prepare a pseudo-acid pulp seed gum emulsion, and coat the base packaging paper once with a coating amount of 2-4 g / m². 2After coating, dry the coated paper in an oven at 60-80℃ for 5-10 minutes, then apply the waterproof and oil-resistant acrylic emulsion a second time, with a coating amount of 4-6 g / m². 2 After coating, the coated paper is dried in an oven at 50-60℃ for 18-22 minutes, and then the coated paper is removed and placed in an indoor environment to stand for 18-36 hours to obtain the packaging paper.

[0034] A further improvement is that the specific operation for preparing the pseudo-physalis seed gum latex is as follows:

[0035] (1) Take acetylated modified pseudo-sour grape seed gum powder and add it to 15-25 times its weight of deionized water under stirring at 200-300 rpm. After adding, increase the stirring speed to 400-500 rpm and continue stirring for 1-2 hours. Let it stand to defoam and obtain pseudo-sour grape seed gum hydrate.

[0036] (2) Take sodium dodecyl polyoxyethylene ether sulfate and dissolve it with 10-12 times the mass of deionized water by stirring. Then add the composite monomer and shear at 1000-1200 rpm for 15-20 min to form a pre-emulsion.

[0037] (3) Prepare a reaction vessel and heat it to 78-80℃. Add 4-6% of the pre-emulsion and 30-35% of the ammonium persulfate solution to it. React for 15-20 minutes.

[0038] (4) Add the remaining pre-emulsion and ammonium sulfate solution to the reaction vessel simultaneously, controlling the addition time to be 2-2.5h and the temperature to be 80±2℃. After the addition is completed, raise the temperature to 85±1℃ and keep it at that temperature for 1-1.5h to obtain the reaction system.

[0039] (5) When the reaction system is cooled to 38-40℃, add the false sourdough seed gum hydrate solution while stirring at 60-80 rpm, and adjust the pH to 7.5-8.5 with ammonia water. Filter the solution to obtain the false sourdough seed gum emulsion.

[0040] The mass ratio of the acetylated modified pseudo-acid pulp seed gum powder, sodium dodecyl polyoxyethylene ether sulfate, composite monomer, and ammonium sulfate solution is 1:0.5-0.8:35-45:0.2-0.4.

[0041] A further improvement is that the preparation operation of the acetylated modified pseudophyte seed gum powder is as follows: commercially available pseudophyte seed gum powder is dispersed in 15-20 times its mass of deionized water, the pH value is adjusted to 8-8.5 with NaOH, and the mixture is stirred and activated for 20-30 minutes. Then, acetic anhydride accounting for 50-70% of the mass of the pseudophyte seed gum powder is added dropwise. After the addition is complete, the mixture is kept at 25-30℃ and stirred for 1.5-2 hours. Then, the pH value is adjusted to 6.5-7.0 with HCl to terminate the reaction. Finally, the acetylated modified pseudophyte seed gum powder is obtained by precipitation, washing, drying, and grinding.

[0042] A further improvement is that the composite monomer is a mixture of butyl acrylate, isooctyl acrylate, methyl methacrylate and acrylic acid in a mass ratio of 25:12:8:1.

[0043] The beneficial effects of this invention are as follows:

[0044] (1) This invention uses alkali-soluble acrylate resin as a protective colloid, and then obtains a nano-acrylate emulsion through core-shell low-temperature copolymerization with hydrophobic acrylate monomers, polyoxyethylene or propylene ether acrylate monomers, crosslinking monomers, etc., and then combines it with functional additives to obtain a waterproof and oil-resistant acrylate emulsion. As a water-based barrier coating, it can be coated on various packaging papers to form a coating similar to a PE film. This coating has outstanding waterproof and oil-resistant barrier properties (waterproof rating Cobb value less than 3g / m). 2 It boasts an oil-resistant rating of 10 or higher (Kit grade), excellent anti-tack and folding endurance, and the coated paper is recyclable, replacing PE-coated paper which is difficult to recycle. Furthermore, this waterproof and oil-resistant acrylic emulsion meets food-grade requirements such as FDA 21CFR176.170, GB9685-2016, and GB4806.8-2022, making it suitable for food packaging paper.

[0045] (2) In the preferred emulsion embodiment, the present invention also adds food-grade triethyl acetyl citrate microcapsules. When applied to packaging paper that requires a lot of folding, the microcapsules in the coating will rupture under folding stress and release triethyl acetyl citrate, thereby plasticizing the polymer and lowering the glass transition temperature Tg. This weakens the intermolecular forces in the folded area and increases the flexibility, thus preventing the coating from disintegrating and cracking after folding and losing its waterproof and oil-proof function. The unfolded area still maintains its original hardness, which is beneficial for packaging shaping.

[0046] (3) In the preferred packaging paper application embodiment, the present invention adds a pseudo-acid pulp seed gum emulsion coating between the waterproof and oil-resistant acrylic emulsion coating and the packaging paper. The flexibility of the pseudo-acid pulp seed gum is used as a buffer layer to effectively absorb folding stress and further improve the folding resistance of the packaging paper. At the same time, it can also enhance the overall adhesion of the coating. In addition, the pseudo-acid pulp seed gum powder used is acetylated to make its hydrophilicity not too strong, ensuring better stability in the secondary coating and later use process. Attached Figure Description

[0047] Figure 1 The images show the microstructure of the packaging paper and blank base paper prepared in Examples 5-9 and Comparative Examples 4-7. Detailed Implementation

[0048] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0049] I. Main Materials

[0050] Packaging paper: purchased from Zhejiang Xianhe Co., Ltd.;

[0051] Acetyl triethyl citrate microcapsules: prepared in the laboratory. The specific method is as follows: chitosan solution (1%, w / v) and gum arabic solution (1%, w / v) are mixed in a beaker at a mass ratio of 1:1 as the wall material. Acetyl triethyl citrate (core-to-wall ratio 1.5:1) is added to the wall material solution. The mixture is then emulsified at 12,000 rpm for 5 minutes in a high-speed shear emulsifier to form a uniform and stable milky white emulsion. The emulsion is then placed on a magnetic stirrer and slowly stirred in a constant temperature water bath at 40°C. The pH of the emulsion was adjusted to 4.0 using 0.1M sodium hydroxide solution, and the solution gradually became turbid. Then, glutaraldehyde solution accounting for 20% of the chitosan mass was added dropwise to the turbid system, and the mixture was stirred at 40°C for 2 hours to allow the cross-linking reaction to proceed fully. After the reaction was completed, the microcapsule suspension was centrifuged at 4000 rpm for 10 minutes, the supernatant was discarded, and the precipitate was washed three times alternately with deionized water and anhydrous ethanol / acetone. Finally, it was vacuum dried to obtain triethyl acetyl citrate microcapsules.

[0052] False groundcherry seed gum powder: purchased from Xi'an Siji Biotechnology Co., Ltd.;

[0053] Unless otherwise specified, all other ingredients are commercially available products.

[0054] II. Conducting the Experiment

[0055] Examples 1-3 and Comparative Examples 1-3

[0056] Table 1: Formulation of Emulsions in Each Group

[0057]

[0058] The emulsion formulations of Examples 1-3 and Comparative Examples 1-3 are shown in Table 1 above, and the specific preparation methods are as follows:

[0059] The preparation method of the waterproof and oil-resistant acrylic emulsion in Example 1 above includes the following steps:

[0060] S1. Add 35% pure water to the reactor, start stirring, add 25% sodium dodecylbenzenesulfonate, disperse for 5 minutes, seal the reactor, heat to 84°C, then evacuate and break the vacuum with nitrogen.

[0061] S2. Add 10% pure water to the high-level tank stirred vessel and start stirring at a rate of 60 r / min. Add the remaining sodium dodecylbenzenesulfonate and sodium allyloxy polyoxyethylene ether sulfate, and stir at a rate of 100 r / min for 12 min. Then add 40% diacetone acrylamide, methacrylic acid and methyl methacrylate, and 90% polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate. Then add n-dodecyl mercaptan. After the addition is complete, stir for 30 min to obtain the high-level tank emulsion for later use.

[0062] S3. When the internal temperature of the reactor is 78℃, add 4% of the high-level tank emulsion. After 2 minutes, add 30% of the ammonium persulfate aqueous solution. Raise the temperature to 84℃ and keep it at that temperature for 12 minutes. Then, add the remaining high-level tank emulsion and the remaining ammonium persulfate aqueous solution dropwise at 0.9 hours and 1.2 hours, respectively. During the dropwise addition, the temperature is controlled at 84℃. After the ammonium persulfate aqueous solution is added, continue to keep it at that temperature for 0.4 hours. Then, lower the temperature to 78℃ and adjust the pH to 8.3 with ammonia water. Keep it at that temperature until the material in the reactor becomes a semi-transparent liquid.

[0063] S4. Add all the remaining monomer to the high-level tank and stir until completely dissolved and homogeneous to obtain the high-level tank monomer solution for later use.

[0064] S5. When the reactor temperature drops to 63°C, add 30% of the high-level tank monomer solution and stir for 13 minutes. When the temperature inside the reactor is 55°C, add 10% of the tert-butyl hydrogen peroxide aqueous solution. After 1.5 minutes of dropwise addition, add 10% of the sodium ascorbate aqueous solution for 4 minutes. After the temperature inside the reactor rises to the highest temperature, keep it at that temperature for 18 minutes.

[0065] S6. Repeat step S5 twice, adding 30% of the high-level tank monomer solution by mass and the remaining 40% of the high-level tank monomer solution respectively to react.

[0066] S7. After the temperature inside the reactor drops to 64°C, add the remaining tert-butyl hydrogen peroxide aqueous solution and sodium ascorbate aqueous solution dropwise over a period of 50 minutes.

[0067] S8. After the temperature inside the reactor drops to 44°C, add adipic acid dihydrazide, followed by white oil defoamer and potassium sorbate. Adjust the solid content to 38%, filter and discharge to obtain waterproof and oil-proof acrylic emulsion.

[0068] The preparation method of the waterproof and oil-resistant acrylic emulsion in Example 2 above includes the following steps:

[0069] S1. Add 40% pure water to the reactor, start stirring, add 30% sodium dodecylbenzenesulfonate, disperse for 8 minutes, seal the reactor, heat to 85°C, then evacuate and break the vacuum with nitrogen.

[0070] S2. Add 12% pure water to the high-level tank stirred vessel and start stirring at a rate of 70 r / min. Add the remaining sodium dodecylbenzenesulfonate and sodium allyloxy polyoxyethylene ether sulfate, and stir at a rate of 110 r / min for 10 min. Then add 50% by weight of diacetone acrylamide, methacrylic acid and methyl methacrylate, and 50% by weight of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate. Then add n-dodecyl mercaptan. After the addition is complete, stir for 35 min to obtain the high-level tank emulsion for later use.

[0071] S3. When the internal temperature of the reactor is 80℃, add 6% of the high-level tank emulsion. After 3 minutes, add 32% of the ammonium persulfate aqueous solution. Raise the temperature to 85℃ and keep it at that temperature for 10 minutes. Then, add the remaining high-level tank emulsion and the remaining ammonium persulfate aqueous solution dropwise for 1 hour and 1.2 hours, respectively. During the dropwise addition, the temperature is controlled at 85℃. After the ammonium persulfate aqueous solution is added, continue to keep it at that temperature for 0.5 hours. Then, lower the temperature to 80℃ and adjust the pH to 8.5 with ammonia water. Keep it at that temperature until the material in the reactor becomes a semi-transparent liquid.

[0072] S4. Add all the remaining monomer to the high-level tank and stir until completely dissolved and homogeneous to obtain the high-level tank monomer solution for later use.

[0073] S5. When the reactor temperature drops to 64°C, add 32% mass of the high-level tank monomer solution and stir for 15 minutes. When the temperature inside the reactor is 58°C, add 12% mass of tert-butyl hydrogen peroxide aqueous solution. After the addition is completed for 2 minutes, add 12% mass of sodium ascorbate aqueous solution for 4.5 minutes. After the temperature inside the reactor rises to the highest temperature, keep it at that temperature for 20 minutes.

[0074] S6. Repeat step S5 twice, adding 32% of the high-level tank monomer solution by mass and the remaining 36% of the high-level tank monomer solution respectively to carry out the reaction.

[0075] S7. After the temperature inside the reactor drops to 65°C, add the remaining tert-butyl hydrogen peroxide aqueous solution and sodium ascorbate aqueous solution dropwise over a period of 60 minutes.

[0076] S8. After the temperature inside the reactor drops to 45°C, add adipic acid dihydrazide, followed by white oil defoamer and potassium sorbate. Adjust the solid content to 40%, filter and discharge to obtain waterproof and oil-proof acrylic emulsion.

[0077] The preparation method of the waterproof and oil-resistant acrylic emulsion in Example 3 above includes the following steps:

[0078] S1. Add 45% pure water to the reactor, start stirring, add 35% sodium dodecylbenzenesulfonate, disperse for 10 minutes, seal the reactor, heat to 86°C, then evacuate and break the vacuum with nitrogen.

[0079] S2. Add 15% pure water to the high-level tank stirred vessel and start stirring at 80 r / min. Add the remaining sodium dodecylbenzenesulfonate and sodium allyloxy polyoxyethylene ether sulfate, and stir at 120 r / min for 8 min. Then add 60% diacetone acrylamide, methacrylic acid and methyl methacrylate, and 10% polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate. Then add n-dodecyl mercaptan. After adding all the ingredients, stir for 40 min to obtain the high-level tank emulsion for later use.

[0080] S3. When the internal temperature of the reactor is 81℃, add 8% of the high-level tank emulsion. After 4 minutes, add 35% of the ammonium persulfate aqueous solution. Raise the temperature to 86℃ and keep it at that temperature for 8 minutes. Then, add the remaining high-level tank emulsion and the remaining ammonium persulfate aqueous solution dropwise for 1.1 hours and 1.3 hours, respectively. During the dropwise addition, the temperature is controlled at 86℃. After the ammonium persulfate aqueous solution is added, continue to keep it at that temperature for 0.6 hours. Then, lower the temperature to 82℃ and adjust the pH to 8.7 with ammonia water. Keep it at that temperature until the material in the reactor becomes a semi-transparent liquid.

[0081] S4. Add all the remaining monomer to the high-level tank and stir until completely dissolved and homogeneous to obtain the high-level tank monomer solution for later use.

[0082] S5. When the reactor temperature drops to 65°C, add 35% of the high-level tank monomer solution and stir for 17 minutes. When the temperature inside the reactor is 60°C, add 15% of the tert-butyl hydrogen peroxide aqueous solution. After 2.5 minutes of addition, add 15% of the ascorbate sodium aqueous solution for 5 minutes. After the temperature inside the reactor rises to the highest temperature, keep it at that temperature for 22 minutes.

[0083] S6. Repeat step S5 twice, adding 35% of the high-level tank monomer solution by mass and the remaining 30% of the high-level tank monomer solution respectively to carry out the reaction.

[0084] S7. After the temperature inside the reactor drops to 66°C, add the remaining tert-butyl hydrogen peroxide aqueous solution and sodium ascorbate aqueous solution dropwise over a period of 70 minutes.

[0085] S8. After the temperature inside the reactor drops to 46°C, add adipic acid dihydrazide, followed by white oil defoamer and potassium sorbate. Adjust the solid content to 43%, filter and discharge to obtain waterproof and oil-proof acrylic emulsion.

[0086] The preparation methods of the waterproof and oil-resistant acrylic emulsions in Comparative Examples 1-3 are the same as those in Example 2.

[0087] Example 4

[0088] A waterproof and oil-resistant acrylic emulsion is prepared based on the formulation and preparation method of Example 2. After filtration in step S8, acetylsicitrin triethyl ester microcapsules with chitosan as the wall material are uniformly added to the emulsion, accounting for 5% of the total mass of the emulsion. The rest is completely consistent with Example 2.

[0089] Example 5

[0090] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: take the base paper for packaging, fix it on a coating machine, and coat the base paper with the waterproof and oil-resistant acrylic emulsion prepared in Example 1, with a coating amount of 4 g / m². 2 After coating, the coated paper is dried in an oven at 50°C for 22 minutes, and then removed and placed in an indoor environment for 18 hours to obtain the packaging paper.

[0091] Example 6

[0092] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: take the base packaging paper, fix it on a coating machine, and coat the base packaging paper with the waterproof and oil-resistant acrylic emulsion prepared in Example 2, with a coating amount of 5 g / m². 2After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0093] Example 7

[0094] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: take the base paper for packaging, fix it on a coating machine, and coat the base paper with the waterproof and oil-resistant acrylic emulsion prepared in Example 3, with a coating amount of 6 g / m². 2 After coating, the coated paper is dried in an oven at 60°C for 18 minutes, and then removed and placed in an indoor environment for 36 hours to obtain the packaging paper.

[0095] Example 8

[0096] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: take the base paper for packaging, fix it on a coating machine, and coat the base paper with the waterproof and oil-resistant acrylic emulsion prepared in Example 4, with a coating amount of 5 g / m². 2 After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0097] Example 9

[0098] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: taking the base packaging paper, fixing it on a coating machine, preparing a pseudo-acid pulp seed gum emulsion and coating the base packaging paper once, with a coating amount of 3g / m². 2 After coating, the coated paper is dried in an oven at 70°C for 8 minutes. Then, the waterproof and oil-resistant acrylic emulsion from Example 4 is used to coat the coated paper a second time, with a coating amount of 5 g / m². 2 After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0099] The specific steps for preparing the pseudo-physalis seed gum latex are as follows:

[0100] (1) Take commercially available false physalis seed gum powder and disperse it in 18 times its mass of deionized water. Adjust the pH value to 8.2 with NaOH and stir for 25 min. Then add acetic anhydride accounting for 60% of the mass of false physalis seed gum powder. After the addition is complete, keep it at 28℃ and stir for 1.5 h. Then adjust the pH value to 7.0 with HCl to terminate the reaction. Finally, after precipitation, washing, drying and grinding, acetylated modified false physalis seed gum powder is obtained. Take acetylated modified false physalis seed gum powder and add it to 20 times its mass of deionized water under 250 rpm stirring. After adding, increase the stirring speed to 450 rpm and continue stirring for 1.5 h. Let it stand to defoam and obtain false physalis seed gum hydrate.

[0101] (2) Take sodium dodecyl polyoxyethylene ether sulfate and dissolve it with 10 times the mass of deionized water. Then add the composite monomer (made by mixing butyl acrylate, isooctyl acrylate, methyl methacrylate and acrylic acid in a mass ratio of 25:12:8:1) and shear at 1100 rpm for 18 min to form a pre-emulsion.

[0102] (3) Prepare a reaction vessel and heat it to 80°C. Add 5% of the total mass of the pre-emulsion and 32% of the total mass of the ammonium persulfate solution to it. React for 18 minutes.

[0103] (4) Add the remaining pre-emulsion and ammonium sulfate solution to the reaction vessel simultaneously, control the addition time to be 2 hours and the temperature to be 80°C. After the addition is completed, raise the temperature to 85°C and keep it at that temperature for 1 hour to obtain the reaction system.

[0104] (5) When the reaction system is cooled to 38°C, the false sourdough seed gum hydrate is added while stirring at 70 rpm, and the pH is adjusted to 8 with ammonia. The mixture is then filtered out to obtain the false sourdough seed gum emulsion.

[0105] The mass ratio of the acetylated modified pseudo-acid pulp seed gum powder, sodium dodecyl polyoxyethylene ether sulfate, composite monomer, and ammonium sulfate solution is 1:0.6:40:0.3.

[0106] Comparative Example 4

[0107] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: taking packaging base paper, fixing it on a coating machine, and coating the packaging base paper with the waterproof and oil-resistant acrylic emulsion prepared in Comparative Example 1, with a coating amount of 5 g / m². 2 After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0108] Comparative Example 5

[0109] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: taking packaging base paper, fixing it on a coating machine, and coating the packaging base paper with the waterproof and oil-resistant acrylic emulsion prepared in Comparative Example 2, with a coating amount of 5 g / m². 2 After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0110] Comparative Example 6

[0111] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: taking packaging base paper, fixing it on a coating machine, and coating the packaging base paper with the waterproof and oil-resistant acrylic emulsion prepared in Comparative Example 3, with a coating amount of 5 g / m². 2 After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0112] Comparative Example 7

[0113] An application of a waterproof and oil-resistant acrylic emulsion in the preparation of packaging paper, the specific steps of which are as follows: taking the base packaging paper, fixing it on a coating machine, preparing a pseudo-acid pulp seed gum emulsion and coating the base packaging paper once, with a coating amount of 3g / m². 2 After coating, the coated paper is dried in an oven at 70°C for 8 minutes. Then, the waterproof and oil-resistant acrylic emulsion from Example 4 is used to coat the coated paper a second time, with a coating amount of 5 g / m². 2 After coating, the coated paper is dried in an oven at 55°C for 20 minutes, and then removed and placed in an indoor environment for 24 hours to obtain the packaging paper.

[0114] The specific steps for preparing the pseudo-physalis seed gum latex are as follows:

[0115] (1) Take commercially available false sourdough seed gum powder and add it to 20 times its weight of deionized water at 250 rpm. After adding, increase the stirring speed to 450 rpm and continue stirring for 1.5 hours. Let it stand to defoam and obtain false sourdough seed gum hydrate.

[0116] (2) Take sodium dodecyl polyoxyethylene ether sulfate and dissolve it with 10 times the mass of deionized water. Then add the composite monomer (made by mixing butyl acrylate, isooctyl acrylate, methyl methacrylate and acrylic acid in a mass ratio of 25:12:8:1) and shear at 1100 rpm for 18 min to form a pre-emulsion.

[0117] (3) Prepare a reaction vessel and heat it to 80°C. Add 5% of the total mass of the pre-emulsion and 32% of the total mass of the ammonium persulfate solution to it. React for 18 minutes.

[0118] (4) Add the remaining pre-emulsion and ammonium sulfate solution to the reaction vessel simultaneously, control the addition time to be 2 hours and the temperature to be 80°C. After the addition is completed, raise the temperature to 85°C and keep it at that temperature for 1 hour to obtain the reaction system.

[0119] (5) When the reaction system is cooled to 38°C, the false sourdough seed gum hydrate is added while stirring at 70 rpm, and the pH is adjusted to 8 with ammonia. The mixture is then filtered out to obtain the false sourdough seed gum emulsion.

[0120] The mass ratio of the pseudo-algae seed gum powder, sodium dodecyl polyoxyethylene ether sulfate, composite monomer, and ammonium sulfate solution is 1:0.6:40:0.3.

[0121] Blank group

[0122] Commercially available packaging paper.

[0123] III. Performance Testing

[0124] (1) Microstructure

[0125] The packaging paper samples prepared in Examples 5-9, Comparative Examples 4-7, and the blank group were cut into test samples of appropriate size, vacuum-sprayed with gold, and placed in the test chamber of a Regulus 8100 cold field emission scanning electron microscope (purchased from Hitachi, Japan) to observe the microstructure of the paper surface.

[0126] (2) Oil resistance test

[0127] Packaging paper samples prepared in Examples 5-9, Comparative Examples 4-7, and the blank group were used. The oil resistance rating of the packaging paper samples was determined according to the test method specified in TAPPI T559 cm-12. The oil resistance rating represents the oil resistance of the packaging paper samples. This method uses castor oil, toluene, and n-heptane to prepare 12 Kit oil resistance test solvents with different surface tensions. The specific preparation data are shown in Table 2 below. The higher the solvent grade, the lower the corresponding surface tension, and the easier it is to penetrate the paper.

[0128] Table 2: Solvent composition for Kit oil resistance test

[0129]

[0130] (3) Waterproof performance test

[0131] Packaging paper samples prepared in Examples 5-9, Comparative Examples 4-7, and the blank group were used to test their water resistance using the Cobb value. A lower Cobb value indicates better water resistance. This experiment was conducted according to the GB / T 1540-2002 standard, using a paper and paperboard absorbency tester (J-CBY100) to test the Cobb value of the paper. Specifically, the packaging paper sample was cut into pieces with an area of ​​12×12 cm². 2 The sample was shaped into a square, and after its mass was measured, it was placed in a testing instrument containing 100 mL of deionized water. The instrument was then inverted so that the packaging paper sample came into contact with the deionized water, and the test time was 30 minutes. Finally, excess water was removed from the sample with a paper towel, and its mass was measured again. The Cobb value was calculated using the following formula:

[0132]

[0133] In the formula: Cobb value is in g / m³ 2 W1 is the mass of the packaging paper sample after it has been in contact with deionized water for 30 minutes and excess water has been removed with a paper towel, in grams; W0 is the initial mass of the packaging paper sample, in grams.

[0134] (4) Retack performance test

[0135] Take the packaging paper samples prepared in Examples 5-9, Comparative Examples 4-7, and the blank group, and cut them into 10×10cm pieces. 2 Two square test paper samples were taken from each group, stacked together, and placed in a 50℃ environment. A pressure of 1 kg / cm² was applied to the samples using a press. 2 Apply pressure for 10 minutes and observe whether there is any back-adhesion between the two paper patterns. The degree of back-adhesion is divided into the following categories from large to small: obvious back-adhesion, slight back-adhesion, mild back-adhesion, and no back-adhesion.

[0136] (5) Flexural endurance test

[0137] Take the packaging paper samples prepared in Examples 5-9, Comparative Examples 4-7, and the blank group, and cut them into 12×12cm pieces. 2 A square test paper sample was prepared, and 5×5 grid lines were marked on the paper sample. The paper sample was folded alternately along each grid line. Each fold was made until the paper was completely flush. Each grid line was folded 10 times. After folding, the oil resistance and water resistance of the test paper sample were tested again according to the test methods (1) and (2) above. The presence of water or oil seepage at the folds was observed. The paper's folding resistance was analyzed by comparing the oil resistance and water resistance before and after folding.

[0138] IV. Results Analysis

[0139] Microscopic morphology images of the packaging paper samples prepared in Examples 5-9 and Comparative Examples 4-7, as well as the blank group, are shown below. Figure 1 As shown in the figure, AJ correspond to Examples 5-9, Comparative Examples 4-7, and the blank group, respectively. It can be seen that the blank group fully displays the fiber structure of the packaging paper and has many pores, which inevitably results in poor waterproofing. Examples 5-8 and Comparative Examples 4-6 are based on a single coating process, where a covering film is clearly formed on the paper surface, sealing the pores, but the fiber morphology is still visible in some areas. Examples 9 and Comparative Example 7 are based on a two-coating process, where a covering film is also formed on the paper surface, with better film uniformity and density, and the fiber morphology is basically not visible.

[0140] The test results of the oil resistance, water resistance, tack resistance, and folding endurance of the packaging paper samples prepared in Examples 5-9, Comparative Examples 4-7, and the blank group are summarized in Table 3 below:

[0141] Table 3: Test results of oil resistance, water resistance, tack resistance, and folding endurance.

[0142]

[0143] Referring to Table 3 above, the packaging papers of Examples 5-7 of the present invention were obtained by applying a single coating of the waterproof and oil-resistant acrylic emulsion formulations based on Examples 1-3, respectively. The results show that their oil resistance level reached level 10 or above, and their waterproof Cobb value was less than 2.4 g / m². 2 It exhibits excellent performance with no re-adhesion, but its folding endurance is only average. After folding, slight water and oil seepage occurred, and its oil and water resistance decreased to some extent. Taking Example 6 as an example, its oil resistance Kit level decreased by 1 level after folding, while its water resistance Cobb value increased by 173.9%. Therefore, it can be applied to some packaging papers with fewer folds.

[0144] The packaging paper of Example 8 was obtained by applying a single coating of the waterproof and oil-resistant acrylic emulsion formulation of Example 4 (which further added triethyl acetylacetic acid microcapsules to the formulation of Example 2). The results showed that it achieved a significant improvement in folding endurance compared to Example 6. There was no water or oil seepage after folding, and the oil-resistant Kit grade did not decrease after folding. The waterproof Cobb value only increased by 50.0% after folding.

[0145] The packaging paper of Example 9 was obtained by applying a second coating (adding pseudo-acid pulp seed gum latex coating to the formulation selected in Example 4) using the preferred waterproof and oil-resistant acrylic emulsion formulation. The results showed that its folding endurance was further improved compared to Example 8. No water or oil seepage was observed after folding, and the oil-resistant Kit grade did not decrease after folding. The waterproof Cobb value only increased by 10.0% after folding, indicating that folding had virtually no impact. Therefore, it can be applied to packaging papers that require extensive folding.

[0146] The packaging paper of Comparative Examples 4-6 was obtained by applying the waterproof and oil-resistant acrylic emulsion formulations of Comparative Examples 1-3 in a single coating process. The results showed that its initial oil and water resistance was average, and it exhibited varying degrees of re-adhesion. In addition, its folding endurance was also average. After folding, oil and water seepage was obvious, and its oil and water resistance was significantly reduced.

[0147] The packaging paper of Comparative Example 7 was obtained by applying a second coating of the waterproof and oil-resistant acrylate emulsion formulation selected in Example 4. However, the pseudo-alkaline seed gum powder used in it was not acetylated. The results showed that compared with Example 9, its initial oil and water resistance performance decreased slightly, and its folding endurance also decreased slightly. Its performance was even worse than that of Example 8 (without a second coating). This shows that directly adding pseudo-alkaline seed gum powder can have a negative effect. Its high hydrophilicity affects the stability of the coating. Therefore, acetylation modification is a necessary step.

[0148] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A waterproof and oil-resistant acrylic emulsion, characterized in that, The raw materials of the emulsion, by weight, include: 10-20 parts methyl methacrylate, 2-8 parts polyethylene glycol diacrylate, 2-8 parts butyl methacrylate, 2-5 parts tert-butyl methacrylate, 2-10 parts butyl acrylate, 3-10 parts isooctyl acrylate, 0.8-1.5 parts diacetone acrylamide, 1.0-2.0 parts methacrylic acid, 0.03-0.08 parts n-dodecyl mercaptan, and 0.02-0. 0.06 parts sodium dodecylbenzenesulfonate, 0.05-0.1 parts sodium allyl oxyalkyl polyoxyethylene ether sulfate, 0.1-0.3 parts potassium sorbate, 0.4-0.8 parts adipic dihydrazide, 0.02-0.06 parts ammonium persulfate, 0.01-0.05 parts tert-butyl hydroperoxide, 0.01-0.05 parts sodium ascorbate, 0.1-0.3 parts white oil defoamer, 1.0-2.0 parts ammonia water, and 57-62 parts pure water; The preparation method of the waterproof and oil-repellent acrylic emulsion includes the following steps: S1. Add 35-45% pure water by mass to the reactor, start stirring, add 25-35% sodium dodecylbenzenesulfonate by mass, disperse for 5-10 minutes, seal the reactor, heat to 84-86℃, then evacuate and break the vacuum with nitrogen. S2. Add 10-15% pure water by mass to the high-level tank stirred vessel, start stirring at a rate of 60-80 r / min, add the remaining sodium dodecylbenzenesulfonate and sodium allyl oxyalkyl polyoxyethylene ether sulfate, and stir at a rate of 100-120 r / min for 8-12 min. Then add 40-60% by mass of diacetone acrylamide, methacrylic acid and methyl methacrylate, and 10-90% by mass of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate. Then add n-dodecyl mercaptan. After the addition is complete, stir for 30-40 min to obtain the high-level tank emulsion for later use. S3. When the internal temperature of the reactor is 78-81℃, add 4-8% of the high-level tank emulsion by mass. After 2-4 minutes, add 30-35% of the ammonium persulfate by mass. Raise the temperature to 84-86℃ and keep it at that temperature for 8-12 minutes. Then, add the remaining high-level tank emulsion and the remaining ammonium persulfate dropwise over 0.9-1.1 hours and 1.2-1.3 hours, respectively. During the dropwise addition, control the temperature at 84-86℃. After the ammonium persulfate is added, continue to keep it at that temperature for 0.4-0.6 hours. Then, lower the temperature to 78-82℃ and adjust the pH to 8.5±0.2 using ammonia water. Keep it at that temperature until the material inside the reactor becomes a semi-transparent liquid. S4. Add all the remaining monomer to the high-level tank and stir until completely dissolved and homogeneous to obtain the high-level tank monomer solution for later use. S5. When the reactor temperature drops to 63-65℃, add 30-35% of the high-level tank monomer solution and stir for 13-17 minutes. When the temperature inside the reactor is 55-60℃, add 10-15% of tert-butyl hydroperoxide. After the addition is completed for 1.5-2.5 minutes, add 10-15% of sodium ascorbate for 4-5 minutes. After the temperature inside the reactor reaches the highest temperature, keep it at that temperature for 18-22 minutes. S6. Repeat step S5 twice, adding 30-35% of the high-level tank monomer solution by mass and the remaining high-level tank monomer solution respectively to carry out the reaction. S7. Wait for the temperature inside the reactor to drop to 64-66℃, and then add the remaining tert-butyl hydrogen peroxide and sodium ascorbate dropwise over a period of 50-70 minutes. S8. After the temperature in the reactor drops to 44-46℃, add adipic acid dihydrazide, then add white oil defoamer and potassium sorbate, adjust the solid content to 38-43%, filter and discharge the material, and uniformly add 4-6% of chitosan-based triethyl acetyl citrate microcapsules to the emulsion to obtain a waterproof and oil-proof acrylate emulsion. The ammonium persulfate, tert-butyl hydroperoxide, and sodium ascorbate are all added in the form of an aqueous solution of the remaining pure water.

2. The application of the waterproof and oil-resistant acrylic emulsion as described in claim 1 in the preparation of packaging paper, characterized in that, The specific steps of the application are as follows: taking the packaging base paper, fixing it on a coating machine, taking the waterproof and oil-proof acrylate emulsion to coat the packaging base paper, the coating amount being 2-8 g / m 2 After coating, the coated paper is dried in an oven at 50-60℃ for 18-22 min, and then the coated paper is taken out and placed in an indoor environment for 18-36 h, to obtain the packaging paper.

3. The application of the waterproof and oil-resistant acrylic emulsion as described in claim 1 in the preparation of packaging paper, characterized in that, The specific steps of the application are as follows: Take the packaging base paper, fix it on the coating machine, prepare the pseudo-alkaline pulp latex, and coat the packaging base paper once with a coating amount of 2-4 g / m³. 2 After coating, dry the coated paper in an oven at 60-80℃ for 5-10 minutes, then apply the waterproof and oil-resistant acrylic emulsion a second time, with a coating amount of 4-6 g / m². 2 After coating, the coated paper is dried in an oven at 50-60℃ for 18-22 minutes, and then the coated paper is removed and placed in an indoor environment to stand for 18-36 hours to obtain the packaging paper.

4. The application according to claim 3, characterized in that, The specific steps for preparing the pseudo-sour pulp seed latex are as follows: (1) Take acetylated modified pseudo-sour grape seed gum powder and add it to 15-25 times its weight of deionized water under stirring at 200-300 rpm. After adding, increase the stirring speed to 400-500 rpm and continue stirring for 1-2 hours. Let it stand to defoam and obtain pseudo-sour grape seed gum hydrate. (2) Take sodium dodecyl polyoxyethylene ether sulfate and dissolve it with 10-12 times the mass of deionized water by stirring. Then add the composite monomer and shear at 1000-1200 rpm for 15-20 min to form a pre-emulsion. (3) Prepare a reaction vessel and heat it to 78-80℃. Add 4-6% of the pre-emulsion and 30-35% of the ammonium persulfate solution to it. React for 15-20 minutes. (4) Add the remaining pre-emulsion and ammonium persulfate solution to the reaction vessel simultaneously, controlling the addition time to be 2-2.5h and the temperature to be 80±2℃. After the addition is completed, raise the temperature to 85±1℃ and keep it at that temperature for 1-1.5h to obtain the reaction system. (5) When the reaction system is cooled to 38-40℃, add the false sourdough seed gum hydrate solution while stirring at 60-80 rpm, and adjust the pH to 7.5-8.5 with ammonia water. Filter the solution to obtain the false sourdough seed gum emulsion. The mass ratio of the acetylated modified pseudo-acid pulp seed gum powder, sodium dodecyl polyoxyethylene ether sulfate, composite monomer, and ammonium persulfate solution is 1:0.5-0.8:35-45:0.2-0.

4.

5. The application according to claim 4, characterized in that, The preparation process of the acetylated modified pseudophyte seed gum powder is as follows: commercially available pseudophyte seed gum powder is dispersed in 15-20 times its mass of deionized water, the pH value is adjusted to 8-8.5 with NaOH, and the mixture is stirred and activated for 20-30 minutes. Then, acetic anhydride accounting for 50-70% of the mass of the pseudophyte seed gum powder is added dropwise. After the addition is complete, the mixture is kept at 25-30℃ and stirred for 1.5-2 hours. Then, the pH value is adjusted to 6.5-7.0 with HCl to terminate the reaction. Finally, the mixture is precipitated, washed, dried, and ground to obtain the acetylated modified pseudophyte seed gum powder.

6. The application according to claim 4, characterized in that, The composite monomer is composed of butyl acrylate, isooctyl acrylate, methyl methacrylate and acrylic acid in a mass ratio of 25:12:8:1.

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