Waterproof and oil-proof acrylate emulsion as well as preparation method and application thereof

Abstract

The invention discloses a waterproof and oil-proof acrylate emulsion as well as a preparation method and application thereof in the field of acrylate emulsion. The emulsion is prepared from the following raw materials: a monomer, a cross-linking agent, an initiator, an emulsifier, a molecular weight regulator, a preservative, a de-foaming agent, a neutralizer and pure water. The monomers comprise methyl methacrylate, polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, diacetone acrylamide and methacrylic acid. The waterproof and oil-proof acrylate emulsion disclosed by the invention can be used as a water-based barrier coating and can be coated on various packaging papers to form a layer of coating similar to a PE (Poly Ethylene) laminated film, the coating has outstanding waterproof and oil-proof barrier properties and excellent after-tack resistance and folding resistance, and the coated paper can be recycled in the later period and can replace the PE laminated paper which is difficult to recycle. Meanwhile, the water-proof and oil-proof acrylate emulsion meets food-grade requirements and can be used for food packaging paper.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acrylic emulsion, in particular to a waterproof and oil-proof acrylic emulsion, a preparation method and application thereof. BACKGROUND

[0002] The waterproof and oil-proof acrylic emulsion is a water-based environmentally friendly coating based on acrylic copolymer, which can bring water resistance and oil resistance through special monomer modification. It provides a high-performance and high-environmental-value functional coating for the packaging paper industry, especially in the field of food packaging, which provides a relatively environmentally friendly and efficient solution to replace traditional plastic film and fluorine-containing oil repellent.

[0003] Pure acrylic emulsion is generally a high molecular polymer emulsion made of acrylic acid, methacrylic acid, and acrylic ester monomers (such as methyl acrylate, ethyl acrylate, butyl acrylate, etc.) through emulsion polymerization process. Its characteristics are good film forming property, high transparency, good weather resistance, environmental protection and non-toxicity. The waterproof and oil-proof function is achieved through molecular design, that is, during polymerization, hydrophobic monomers (such as styrene, long-chain acrylate) are introduced to provide water repellency and prevent liquid water penetration, and oleophobic monomers, such as fluorine-containing monomers (PFOA, PFOS), are introduced to provide oil repellency. However, due to environmental and health problems, modern pure acrylic systems usually use non-fluorine oil-repellent monomers (such as long-chain acrylate polymers, silicon-modified acrylates) to provide oil repellency.

[0004] However, the existing waterproof and oil-proof pure acrylic emulsion has certain waterproof and oil-proof properties, but when applied to packaging paper, its anti-stickiness and folding resistance cannot meet the requirements, resulting in poor application effect. The specific analysis is as follows:

[0005] Anti-stickiness is based on production process requirements. After coating, the paper needs to be wound into a roll (paper roll) or stacked together for storage and transportation. If the coating is sticky, the paper roll or stack will stick together and cannot be easily separated. On the other hand, it is based on storage environment challenges. The paper may be stored in an environment with large temperature difference and high humidity. High temperature and high humidity will accelerate the movement of polymer molecular chains, causing the coating to become soft and sticky, and more prone to stickiness. Poor anti-stickiness can cause a series of problems such as difficult unwinding, surface damage, printing and color matching problems, and finished product scrap.

[0006] Folding resistance is based on the inevitable requirements of packaging on the one hand, and most paper packaging needs to be folded, indented, slotted and the like to be shaped into cartons, paper bags, paper bowls and the like; on the other hand, based on the requirements in the process of use, consumers when using packaging paper (such as squeezing take-out bags), products in the process of transportation are subjected to jolt, which will make the paper bend and fold. Poor folding resistance will lead to a series of problems such as cracking of coating, loss of waterproof and oil-proof function, appearance damage and the like.

[0007] Therefore, it is urgent for us to optimize and improve the composition and process of the existing waterproof and oil-proof acrylate emulsion to improve its anti-sticking and folding resistance. SUMMARY

[0008] The present application aims to provide a waterproof and oil-proof acrylate emulsion and its preparation method and application, which solves the problem of poor anti-sticking and folding resistance of the existing waterproof and oil-proof acrylate emulsion.

[0009] The present application realizes the above-mentioned purpose through the following technical solutions:

[0010] A waterproof and oil-proof acrylate emulsion, the raw materials of the emulsion include monomer, crosslinking agent, initiator, emulsifier, molecular weight regulator, preservative, defoaming agent, neutralizing agent and pure water;

[0011] Among them, the monomer includes methyl methacrylate, polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate, isooctyl acrylate, diacetone acrylamide and methacrylic acid.

[0012] Further improvement lies in that,

[0013] The crosslinking agent adopts adipic acid dihydrazide;

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

[0015] The emulsifier includes sodium dodecyl benzene sulfonate and allyloxy alkyl polyoxyethylene ether sodium sulfate;

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

[0017] The preservative adopts potassium sorbate;

[0018] The defoaming agent adopts white oil defoaming agent;

[0019] The neutralizing agent adopts ammonia water.

[0020] Further improvement lies in that the raw materials of the emulsion include, in terms of mass fraction, 10-20 parts of methyl methacrylate, 2-8 parts of polyethylene glycol diacrylate, 2-8 parts of butyl methacrylate, 2-5 parts of tert-butyl methacrylate, 2-10 parts of butyl acrylate, 3-10 parts of isooctyl acrylate, 0.8-1.5 parts of diacetone acrylamide, 1.0-2.0 parts of methacrylic acid, 0.03-0.08 parts of n-dodecyl mercaptan, 0.02-0.06 parts of sodium dodecyl benzene sulfonate, 0.05-0.1 parts of sodium allyloxy alkyl polyoxyethylene ether sulfate, 0.1-0.3 parts of potassium sorbate, 0.4-0.8 parts of adipic acid dihydrazide, 0.02-0.06 parts of ammonium persulfate, 0.01-0.05 parts of tert-butyl hydroperoxide, 0.01-0.05 parts of sodium ascorbate, 0.1-0.3 parts of white oil defoamer, 1.0-2.0 parts of ammonia water, and 57-62 parts of pure water.

[0021] The application further provides a preparation method of the waterproof and oil-proof acrylate emulsion, which comprises the following steps:

[0022] S1, adding 35-45% of pure water into a reaction kettle, starting stirring, adding 25-35% of sodium dodecyl benzene sulfonate, dispersing for 5-10 min, sealing the reaction kettle, heating to 84-86℃, then vacuumizing and breaking the vacuum with nitrogen;

[0023] S2, adding 10-15% of pure water into a high tank stirring kettle, starting stirring at a speed of 60-80 r / min, adding the remaining sodium dodecyl benzene sulfonate and sodium allyloxy polyoxyethylene ether sulfate, stirring at a speed of 100-120 r / min for 8-12 min, then adding 40-60% of diacetone acrylamide, methacrylic acid and methyl methacrylate, and 10-90% of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate, and then adding n-dodecyl mercaptan, stirring for 30-40 min after the addition is completed to obtain a high tank emulsion for standby;

[0024] S3, when the internal temperature of the reaction kettle is 78-81℃, adding 4-8% of the high tank emulsion, adding 30-35% of ammonium persulfate after 2-4 min, increasing the temperature to 84-86℃ and keeping for 8-12 min, then adding the remaining high tank emulsion and the remaining ammonium persulfate dropwise, the dropwise adding time being 0.9-1.1 h and 1.2-1.3 h respectively, the temperature being controlled at 84-86℃ during the dropwise adding process, continuing to keep for 0.4-0.6 h after the dropwise adding of ammonium persulfate is completed, then decreasing the temperature to 78-82℃, adjusting the PH to 8.5±0.2 through ammonia water, and keeping until the material in the kettle becomes a translucent liquid;

[0025] S4, add all the remaining monomers into the high tank, stir until completely dissolved and uniform, to obtain a high tank monomer solution for standby;

[0026] S5, when the reaction kettle is cooled to 63-65 DEG C, 30-35% of the mass of the high tank monomer solution is added, and stirred for 13-17 min, when the kettle temperature is 55-60 DEG C, 10-15% of the mass of t-butyl hydroperoxide is added, 10-15% of the mass of sodium ascorbate is added after 1.5-2.5 min of dropwise addition, and the dropwise addition time is 4-5 min, and after the kettle is heated to the highest temperature, it is kept for 18-22 min;

[0027] S6, repeat step S5 twice, respectively add 30-35% of the mass of the high tank monomer solution, and the remaining high tank monomer solution for reaction;

[0028] S7, when the reaction kettle is cooled to 64-66 DEG C, the remaining t-butyl hydroperoxide and sodium ascorbate are added dropwise, and the dropwise addition time is 50-70 min;

[0029] S8, when the reaction kettle is cooled to 44-46 DEG C, add adipic acid dihydrazide, then add white oil defoaming agent and potassium sorbate, adjust the solid content to 38-43%, and filter the discharge to obtain a waterproof and oil-proof acrylate emulsion;

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

[0031] Further improvement is that in step S8, after filtering the discharge, 4-6% of acetyl citrate triethyl citrate microcapsules with chitosan as wall material are uniformly mixed into the emulsion based on the total mass of the emulsion.

[0032] The application also provides an application of the waterproof and oil-proof acrylate emulsion in preparing packaging paper, and the specific steps of the application are as follows: taking packaging base paper, fixing it on a coating machine, taking the waterproof and oil-proof acrylate emulsion, and coating the packaging base paper, the coating amount being 2-8 g / m 2 After coating is completed, the coated paper is dried in an oven at 50-60 DEG C for 18-22 min, then the coated paper is taken out and placed in an indoor environment for 18-36 h to obtain packaging paper.

[0033] The application also provides another application of the waterproof and oil-proof acrylate emulsion in preparing packaging paper, and the specific steps of the application are as follows: taking packaging base paper, fixing it on a coating machine, preparing a false acer seed latex emulsion, and coating the packaging base paper once, the coating amount being 2-4 g / m 2After the coating is completed, the coated paper is dried in an oven at 60-80℃ for 5-10min, and the coated paper is then coated again with the waterproof and oil-proof acrylic emulsion at a coating amount of 4-6g / m 2 After the coating is completed, the coated paper is dried in an oven at 50-60℃ for 18-22min, and then the coated paper is taken out and placed in an indoor environment for 18-36h to obtain the packaging paper.

[0034] Further improvement lies in that the specific operation for preparing the latex of fructus roxburghii-plantaginis seed is as follows:

[0035] (1) The acetylated modified fructus roxburghii-plantaginis seed powder is added to deionized water with a mass of 15-25 times and under the condition of stirring at 200-300rpm, and after the addition, the stirring speed is increased to 400-500rpm for continuous stirring for 1-2h, and then the fructus roxburghii-plantaginis seed gel hydration liquid is obtained after standing and defoaming;

[0036] (2) Sodium dodecyl polyoxyethylene ether sulfate is taken and dissolved in deionized water with a mass of 10-12 times, and then a composite monomer is added, and high-speed shearing is performed at 1000-1200rpm for 15-20min to form a pre-emulsion;

[0037] (3) A reaction kettle is prepared and heated to 78-80℃, and then 4-6% of the pre-emulsion in the total mass of the pre-emulsion and 30-35% of the ammonium sulfate solution in the total mass of the ammonium sulfate solution are added, and the reaction is performed for 15-20min;

[0038] (4) The remaining pre-emulsion and ammonium sulfate solution are synchronously added to the reaction kettle, the dropping time is controlled to be 2-2.5h, the temperature is 80±2℃, after the dropping is completed, the temperature is increased to 85±1℃ and kept for 1-1.5h to obtain a reaction system;

[0039] (5) When the reaction system is cooled to 38-40℃, the fructus roxburghii-plantaginis seed gel hydration liquid is added under the condition of stirring at 60-80rpm, and the pH is adjusted to 7.5-8.5 by using ammonia water, and then the filtrate is obtained to obtain the fructus roxburghii-plantaginis seed latex;

[0040] The mass ratio between the acetylated modified fructus roxburghii-plantaginis seed 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] Further improvement lies in that the preparation operation of the acetylated modified fructus jujubae seed gum powder is as follows: commercially available fructus jujubae seed gum powder is dispersed in 15-20 times of mass of deionized water, the pH value is adjusted to 8-8.5 by using NaOH, stirring and activation is carried out for 20-30 min, 50-70 % of acetic anhydride based on the mass of the fructus jujubae seed gum powder is added dropwise, after dropwise addition, reaction is carried out at 25-30 DEG C under the condition of stirring and heat preservation for 1.5-2 h, then the pH value is adjusted to 6.5-7.0 by using HCl to terminate the reaction, and finally the acetylated modified fructus jujubae seed gum powder is obtained through precipitation, washing, drying and grinding.

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

[0043] The beneficial effects of the present application are as follows:

[0044] (1) In the present application, alkali-soluble acrylate resin is used as protective colloid, and then hydrophobic acrylate monomer, polyoxyethylene or propylene ether acrylate monomer, crosslinking monomer and the like are used to obtain nano acrylate emulsion through core-shell low-temperature copolymerization, and then functional additives are combined to obtain waterproof and oil-proof acrylate emulsion, which is used as water-based barrier coating and can be coated on various packaging papers to form a coating layer similar to PE film coating, the coating layer has outstanding waterproof and oil-proof barrier properties (waterproof level Cobb value is less than 3 g / m 2 , oil-proof level Kit can reach more than 10 levels), and has excellent anti-back-sticking and folding resistance, and the coated paper can be recycled in later period, replacing PE film paper which is difficult to recycle and reuse. At the same time, the waterproof and oil-proof acrylate emulsion meets the food-grade requirements of FDA 21 CFR 176.170, GB 9685-2016, GB 4806.8-2022 and the like, and can be used for food packaging paper.

[0045] (2) In the preferred emulsion embodiment, food-grade acetyl citrate triethyl microcapsules are also added, so that when the emulsion is applied to packaging paper which needs a large number of folding operations, the microcapsules in the coating layer will break under folding stress to release acetyl citrate triethyl, so as to achieve the effect of plasticizing polymer and reducing glass transition temperature Tg, so that the intermolecular force in the folding area is weakened and the flexibility is increased, thereby avoiding the disintegration and cracking of the coating layer after folding and losing the waterproof and oil-proof function, while the non-folding area still maintains the original hardness, thereby being beneficial to packaging and shaping.

[0046] (3) In the preferred packaging paper application embodiment, the present application adds a latex coating of physic nut seed glue between the waterproof and oil-proof acrylate emulsion coating and the packaging paper, uses its flexibility as a buffer layer to effectively absorb folding stress, further improves the folding resistance of the packaging paper, and also enhances the overall adhesion of the coating; in addition, the physic nut seed glue powder used is acetylated, so that its hydrophilicity is not too strong, ensuring better stability during secondary coating and later use. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 Micrographs of the packaging paper prepared in Examples 5-9 and Comparative Examples 4-7 and the blank group base paper. DETAILED DESCRIPTION

[0048] It is necessary to point out here that the following detailed description is only used to further illustrate the present application and cannot be understood 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 base paper: purchased from Zhejiang Xianhe Co., Ltd.;

[0051] Acetyl citric acid triethyl ester microcapsule: self-made in the laboratory, the specific method is as follows: take chitosan solution (1%, w / v) and gum arabic solution (1%, w / v) and mix them in a beaker at a mass ratio of 1:1 as wall material, add acetyl citric acid triethyl ester to the wall material solution (core-wall ratio 1.5:1), and then emulsify the system under a high-speed shearing emulsifier at 12000 rpm for 5 min to form a uniform and stable milky white emulsion. Slowly stir the emulsion in a constant temperature water bath at 40°C with a magnetic stirrer. Adjust the pH value of the emulsion to 4.0 with 0.1M sodium hydroxide solution, the solution gradually becomes turbid, then add 20% glutaraldehyde solution based on the mass of chitosan dropwise to the turbid system, and continue to stir at 40°C for 2h to make the crosslinking reaction fully proceed. After the reaction is completed, centrifuge the microcapsule suspension at 4000 rpm for 10 min, discard the supernatant, and wash the precipitate with deionized water and anhydrous ethanol / acetone alternately for 3 times, and finally vacuum dry to obtain acetyl citric acid triethyl ester microcapsule.

[0052] Physic nut seed glue powder: purchased from Xi'an Four Seasons Biotechnology Co., Ltd.;

[0053] Other ingredients have no special instructions and are ordinary commercially available products.

[0054] II. Implementation experiment

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

[0056] Table 1: Formulation table of emulsions of 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, respectively:

[0059] The preparation method of the waterproof and oil-repellent acrylate emulsion of Example 1 above comprises the following steps:

[0060] S1, 35% by mass of pure water was added to the reaction kettle, stirring was started, 25% by mass of sodium dodecyl benzene sulfonate was added, and the reaction kettle was closed, heated to 84°C, then vacuumed, and broken vacuum with nitrogen;

[0061] S2, 10% by mass of pure water was added to the high tank stirring kettle, stirring was started at a speed of 60 r / min, the remaining sodium dodecyl benzene sulfonate and allyloxy polyoxyethylene ether sodium sulfate were added, stirring was continued at a speed of 100 r / min for 12 min, then 40% by mass of diacetone acrylamide, methyl methacrylate and methyl methacrylate were added, as well as 90% by mass of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate, and then n-dodecyl mercaptan was added, and after the addition was completed, stirring was continued for 30 min to obtain a high tank emulsion for standby;

[0062] S3, when the internal temperature of the reaction kettle was 78°C, 4% by mass of the high tank emulsion was added, 2 min later, 30% by mass of ammonium persulfate aqueous solution was added, the temperature was raised to 84°C and kept for 12 min, then the remaining high tank emulsion and the remaining ammonium persulfate aqueous solution were added dropwise, the dropwise addition time was 0.9 h and 1.2 h, respectively, and the temperature was controlled at 84°C during the dropwise addition process, after the dropwise addition of the ammonium persulfate aqueous solution was completed, the temperature was kept for 0.4 h, then the temperature was lowered to 78°C, and the PH was adjusted to 8.3 by ammonia water, and the temperature was kept until the material in the kettle became a translucent liquid;

[0063] S4, all the remaining monomers were added to the high tank, and stirring was continued until complete dissolution and uniformity were achieved to obtain a high tank monomer solution for standby;

[0064] S5, when the reaction kettle was cooled to 63°C, 30% by mass of the high tank monomer solution was added, and stirring was continued for 13 min, when the temperature in the kettle was 55°C, 10% by mass of tert-butyl hydroperoxide aqueous solution was added, 1.5 min after the dropwise addition was completed, 10% by mass of sodium ascorbate aqueous solution was added dropwise, and the dropwise addition time was 4 min, and after the temperature in the kettle was raised to the highest temperature, the temperature was kept for 18 min;

[0065] S6, repeat step S5 twice, respectively add 30% mass of high tank monomer solution, and the remaining 40% high tank monomer solution for reaction;

[0066] S7, when the reaction kettle is cooled to 64℃, while adding the remaining tert-butyl hydroperoxide aqueous solution and sodium ascorbate aqueous solution, the dropwise adding time is 50 min;

[0067] S8, when the reaction kettle is cooled to 44℃, add adipic dihydrazide, then add white oil defoaming agent and potassium sorbate, adjust the solid content to 38%, filter the discharge to obtain the waterproof and oil-proof acrylate emulsion.

[0068] The preparation method of the waterproof and oil-proof acrylate emulsion of the above embodiment 2, comprising the following steps:

[0069] S1, add 40% mass of pure water to the reaction kettle, start stirring, add 30% mass of sodium dodecyl benzene sulfonate, disperse for 8 min, seal the reaction kettle, heat to 85℃, then vacuumize, and break the vacuum with nitrogen;

[0070] S2, add 12% mass of pure water to the high tank stirring kettle, start stirring at a speed of 70 r / min, add the remaining sodium dodecyl benzene sulfonate, and allyloxy polyoxyethylene ether sodium sulfate, then stir at a speed of 110 r / min for 10 min, then add 50% mass of diacetone acrylamide, methyl methacrylate, and 50% mass of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate, then add n-dodecyl mercaptan, after adding, stir for 35 min, to obtain the high tank emulsion for standby;

[0071] S3, when the internal temperature of the reaction kettle is 80℃, add 6% mass of the high tank emulsion, add 32% mass of ammonium persulfate aqueous solution after 3 min, heat to 85℃ and keep for 10 min, then add the remaining high tank emulsion and the remaining ammonium persulfate aqueous solution, the dropwise adding time is 1 h and 1.2 h respectively, the temperature is controlled at 85℃ during the dropwise adding process, after the ammonium persulfate aqueous solution is added dropwise, continue to keep for 0.5 h, then cool to 80℃, and adjust the PH to 8.5 by ammonia water, keep until the material in the kettle becomes a translucent liquid;

[0072] S4, add all the remaining monomers to the high tank, stir until completely dissolved and uniform, to obtain the high tank monomer solution for standby;

[0073] S5, when the reactor is cooled to 64℃, 32% of the monomer solution in the head tank is added, stirring for 15 min, when the temperature in the reactor is 58℃, 12% of the tert-butyl hydroperoxide aqueous solution is added, 2 min after the completion of the dropwise addition, 12% of the sodium ascorbate aqueous solution is added, and the dropwise addition time is 4.5 min, after the temperature in the reactor is increased to the highest temperature, it is kept for 20 min;

[0074] S6, step S5 is repeated twice, 32% of the monomer solution in the head tank is added, and the remaining 36% of the monomer solution in the head tank is added for reaction;

[0075] S7, when the temperature in the reactor is cooled to 65℃, the remaining tert-butyl hydroperoxide aqueous solution and sodium ascorbate aqueous solution are added dropwise, and the dropwise addition time is 60 min;

[0076] S8, when the temperature in the reactor is cooled to 45℃, adipic dihydrazide is added, then white oil defoaming agent and potassium sorbate are added, the solid content is adjusted to 40%, and the product is filtered to obtain a waterproof and oil-proof acrylate emulsion.

[0077] The preparation method of the waterproof and oil-proof acrylate emulsion of the above embodiment 3 comprises the following steps:

[0078] S1, 45% of pure water is added to the reactor, stirring is started, 35% of sodium dodecyl benzene sulfonate is added, and is dispersed for 10 min, the reactor is sealed, heated to 86℃, then vacuumized, and broken by nitrogen;

[0079] S2, 15% of pure water is added to the head tank stirring kettle, stirring is started at a speed of 80 r / min, the remaining sodium dodecyl benzene sulfonate and allyloxy polyoxyethylene ether sodium sulfate are added, stirring is continued at a speed of 120 r / min for 8 min, then 60% of diacetone acrylamide, methyl methacrylate and methyl methacrylate are added, and 10% of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate are added, then n-dodecyl mercaptan is added, and stirring is continued for 40 min after the completion of the addition to obtain a head tank emulsion for standby;

[0080] S3, when the temperature in the reactor is 81℃, 8% of the head tank emulsion is added, 4 min later, 35% of the ammonium persulfate aqueous solution is added, the temperature is increased to 86℃ and kept for 8 min, then the remaining head tank emulsion and the remaining ammonium persulfate aqueous solution are added dropwise, the dropwise addition time is 1.1 h and 1.3 h respectively, the temperature is controlled at 86℃ during the dropwise addition, after the completion of the dropwise addition of the ammonium persulfate aqueous solution, it is kept for 0.6 h, then the temperature is decreased to 82℃, the PH is adjusted to 8.7 by ammonia water, and it is kept until the material in the reactor becomes a translucent liquid;

[0081] S4, add all the remaining monomers into the high tank, stir until completely dissolved and uniform, to obtain a high tank monomer solution for standby;

[0082] S5, when the reactor is cooled to 65℃, add 35% mass of the high tank monomer solution, stir for 17 min, when the temperature in the reactor is 60℃, add 15% mass of the tert-butyl hydroperoxide aqueous solution, drop 15% mass of the sodium ascorbate aqueous solution after 2.5 min of drop completion, and the drop time is 5 min, after the reactor is heated to the highest temperature, keep for 22 min;

[0083] S6, repeat step S5 twice, respectively add 35% mass of the high tank monomer solution, and the remaining 30% high tank monomer solution for reaction;

[0084] S7, when the reactor is cooled to 66℃, drop the remaining tert-butyl hydroperoxide aqueous solution and sodium ascorbate aqueous solution at the same time, and the drop time is 70 min;

[0085] S8, when the reactor is cooled to 46℃, add adipic acid dihydrazide, then add white oil defoaming agent and potassium sorbate, adjust the solid content to 43%, filter the discharge to obtain a waterproof and oil-proof acrylate emulsion.

[0086] The preparation method of the waterproof and oil-proof acrylate emulsion of the above comparative examples 1-3 is the same as that of example 2.

[0087] Example 4

[0088] A waterproof and oil-proof acrylate emulsion, on the basis of the formula and preparation method of example 2, after filtering the discharge in step S8, uniformly mix 5% of acetyl citrate triethyl citrate microcapsules with chitosan as wall material in the emulsion, and other aspects are the same as example 2.

[0089] Example 5

[0090] The application of a waterproof and oil-proof acrylate emulsion in preparing packaging paper, the specific steps of the application are as follows: take the packaging base paper, fix it on the coating machine, take the waterproof and oil-proof acrylate emulsion prepared in example 1 to coat the packaging base paper, the coating amount is 4g / m 2 , after coating, dry the coated paper in an oven at 50℃ for 22 min, then take out the coated paper and place it in the indoor environment for 18 h, to obtain the packaging paper.

[0091] Example 6

[0092] The application of a waterproof and oil-proof acrylate emulsion in preparing packaging paper, the specific steps of the application are as follows: take the packaging base paper, fix it on the coating machine, take the waterproof and oil-proof acrylate emulsion prepared in example 2 to coat the packaging base paper, the coating amount is 5g / m 2After the coating is completed, the coated paper is dried in an oven at 55℃ for 20min, and then the coated paper is taken out and placed in an indoor environment for 24h, to obtain the packaging paper.

[0093] Example 7

[0094] The application of a waterproof and oil-proof acrylate emulsion in the preparation of packaging paper, 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 prepared in Example 3 to coat the packaging base paper, the coating amount is 6g / m 2 After the coating is completed, the coated paper is dried in an oven at 60℃ for 18min, and then the coated paper is taken out and placed in an indoor environment for 36h, to obtain the packaging paper.

[0095] Example 8

[0096] The application of a waterproof and oil-proof acrylate emulsion in the preparation of packaging paper, 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 prepared in Example 4 to coat the packaging base paper, the coating amount is 5g / m 2 After the coating is completed, the coated paper is dried in an oven at 55℃ for 20min, and then the coated paper is taken out and placed in an indoor environment for 24h, to obtain the packaging paper.

[0097] Example 9

[0098] The application of a waterproof and oil-proof acrylate emulsion in the preparation of packaging paper, the specific steps of the application are as follows: taking the packaging base paper, fixing it on a coating machine, taking the latex emulsion of false acid plum seeds to coat the packaging base paper once, the coating amount is 3g / m 2 After the coating is completed, the coated paper is dried in an oven at 70℃ for 8min, and then the waterproof and oil-proof acrylate emulsion prepared in Example 4 is taken to coat the coated paper again, the coating amount is 5g / m 2 After the coating is completed, the coated paper is dried in an oven at 55℃ for 20min, and then the coated paper is taken out and placed in an indoor environment for 24h, to obtain the packaging paper.

[0099] The specific operation of preparing the latex emulsion of false acid plum seeds is as follows:

[0100] (1) Take the commercially available Fructus Physalis seed gum powder and disperse it in 18 times the 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 the Fructus Physalis seed gum powder, and after the addition is complete, react at 28℃ for 1.5 h under stirring. Then, adjust the pH value to 7.0 with HCl to terminate the reaction. Finally, after precipitation, washing, drying, and grinding, the acetylated modified Fructus Physalis seed gum powder is obtained. Take the acetylated modified Fructus Physalis seed gum powder and add it to 20 times the mass of deionized water under stirring at 250 rpm. After adding, increase the stirring speed to 450 rpm and continue stirring for 1.5 h. After standing to remove bubbles, the Fructus Physalis seed gum hydration liquid is obtained.

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

[0102] (3) Prepare a reaction kettle and heat it to 80℃. Add 5% of the total mass of the pre-emulsion to the reaction kettle, as well as 32% of the total mass of the ammonium persulfate solution. React for 18 min.

[0103] (4) Simultaneously add the remaining pre-emulsion and ammonium sulfate solution to the reaction kettle. Control the dropwise addition time to be 2 h and the temperature to be 80℃. After the dropwise addition is complete, heat to 85℃ and maintain for 1 h to obtain the reaction system.

[0104] (5) When the reaction system cools to 38℃, add the Fructus Physalis seed gum hydration liquid under stirring at 70 rpm, and adjust the pH to 8 with ammonia water. Filter the product to obtain the Fructus Physalis seed gum emulsion.

[0105] The mass ratio between the acetylated modified Fructus Physalis 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] The application of a waterproof and oil-repellent acrylate emulsion in the preparation of packaging paper. The specific steps of the application are as follows: take the packaging base paper and fix it on a coating machine. Take the waterproof and oil-repellent acrylate emulsion prepared in Comparative Example 1 and coat the packaging base paper. The coating amount is 5 g / m 2 After coating is completed, dry the coated paper in an oven at 55℃ for 20 min. Then, take out the coated paper and place it in an indoor environment for 24 h to obtain the packaging paper.

[0108] Comparative Example 5

[0109] The application of a waterproof and oil-proof acrylate emulsion in the preparation of packaging paper, 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 prepared in the comparative example 2 to coat the packaging base paper, the coating amount being 5 g / m 2 After the coating is completed, the coated paper is dried in an oven at 55 DEG C for 20 min, then the coated paper is taken out and placed in an indoor environment for 24 h, and the packaging paper is obtained.

[0110] Comparative example 6

[0111] The application of a waterproof and oil-proof acrylate emulsion in the preparation of packaging paper, 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 prepared in the comparative example 3 to coat the packaging base paper, the coating amount being 5 g / m 2 After the coating is completed, the coated paper is dried in an oven at 55 DEG C for 20 min, then the coated paper is taken out and placed in an indoor environment for 24 h, and the packaging paper is obtained.

[0112] Comparative example 7

[0113] The application of a waterproof and oil-proof acrylate emulsion in the preparation of packaging paper, 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 prepared in the comparative example 3 to coat the packaging base paper, the coating amount being 5 g / m 2 After the coating is completed, the coated paper is dried in an oven at 55 DEG C for 20 min, then the coated paper is taken out and placed in an indoor environment for 24 h, and the packaging paper is obtained. 2 After the coating is completed, the coated paper is dried in an oven at 55 DEG C for 20 min, then the coated paper is taken out and placed in an indoor environment for 24 h, and the packaging paper is obtained.

[0114] The specific operation of preparing the physic nut seed gum emulsion is as follows:

[0115] (1) taking the commercially available physic nut seed gum powder, adding it into 20 times of mass and 250 rpm stirring state of deionized water, after adding, increasing the stirring speed to 450 rpm and continuously stirring for 1.5 h, and then standing to defoam to obtain the physic nut seed gum hydration liquid;

[0116] (2) taking sodium dodecyl polyoxyethylene ether sulfate and stirring and dissolving it with 10 times of mass of deionized water, then adding the composite monomer (which is mixed by butyl acrylate, isooctyl acrylate, methyl methacrylate and acrylic acid in a mass ratio of 25:12:8:1), and high-speed shearing for 18 min to form a pre-emulsion;

[0117] (3) Prepare a reaction kettle and heat to 80℃, add 5% of the total mass of the pre-emulsion to the reaction kettle, and add 32% of the total mass of the ammonium persulfate solution to the reaction kettle, and react for 18 min;

[0118] (4) Add the remaining pre-emulsion and ammonium sulfate solution to the reaction kettle simultaneously, control the dropwise addition time to be 2 h, and the temperature to be 80℃, after the dropwise addition is completed, heat to 85℃ and keep for 1 h to obtain a reaction system;

[0119] (5) When the reaction system is cooled to 38℃, add the hydrated liquid of the physic nut seed gum under the condition of 70 rpm stirring, and adjust the pH to 8 with ammonia water, and filter the product to obtain a physic nut seed gum emulsion;

[0120] The mass ratio between the physic nut 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] The packaging base paper was purchased.

[0123] III. Performance test

[0124] (1) Microstructure

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

[0126] (2) Oil resistance test

[0127] The packaging paper samples prepared in Examples 5-9 and Comparative Examples 4-7 and the blank group were taken, and the oil resistance grade of the packaging paper samples was determined according to the test method specified in TAPPI T559 cm-12, and the oil resistance of the packaging paper samples was represented by the oil resistance grade. The method uses castor oil, toluene, and n-heptane to prepare 12 kinds of Kit oil resistance test solvents with different surface tensions, and the specific preparation data is shown in Table 2. The higher the solvent grade, the smaller the corresponding surface tension, and the easier the penetration of the paper.

[0128] Table 2: Kit oil resistance test solvent composition

[0129]

[0130] (3) Water resistance 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 moisture 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 is obtained by applying the preferred waterproof and oil-proof acrylate emulsion formula of Example 4 twice (increasing the coating of the physic nut seed emulsion based on Example 8), and the results show that it is further improved in folding resistance compared with Example 8, there is no water and oil leakage after folding, the oil-proof Kit grade does not decrease after folding, and the waterproof Cobb value only increases by 10.0% after folding, which means that folding has little effect. Therefore, it can be applied to some packaging papers that require a large number of folds.

[0146] The packaging papers of Comparative Examples 4-6 are obtained by applying the waterproof and oil-proof acrylate emulsion formulas of Comparative Examples 1-3 once respectively, and the results show that their initial oil-proof and waterproof performance is general, and they all have different degrees of back-sticking phenomenon, in addition, the folding resistance is also general, and there is obvious oil and water leakage after folding, and the oil-proof and waterproof performance is also significantly decreased.

[0147] The packaging paper of Comparative Example 7 is obtained by applying the preferred waterproof and oil-proof acrylate emulsion formula of Example 4 twice, but the physic nut seed powder used is not acetylated, and the results show that its initial oil-proof and waterproof performance has a small decrease compared with Example 9, and the folding resistance also has a small decrease, which is even worse than Example 8 (without twice coating), which shows that directly adding physic nut seed powder can have a negative effect, and its high hydrophilicity affects the stability of the coating, so acetylation is a necessary step.

[0148] The above-described examples only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the present patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A water and oil repellent acrylate emulsion, characterized by, The raw materials of the emulsion include monomers, cross-linking agents, initiators, emulsifiers, molecular weight regulators, preservatives, defoaming agents, 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.

2. The waterproof and oil-proof acrylate emulsion according to claim 1, characterized in that, The cross-linking agent is adipic acid dihydrazide; The initiators include ammonium persulfate, tert-butyl hydroperoxide and sodium ascorbate; The emulsifiers include sodium dodecyl benzene sulfonate and allyloxy alkyl polyoxyethylene ether sodium sulfate; The molecular weight regulator is n-dodecyl mercaptan; The preservative is potassium sorbate; The defoaming agent is white oil defoaming agent; The neutralizing agent is ammonia water.

3. The water and oil repellent acrylate emulsion according to claim 2, characterized in that, The raw materials of the emulsion include, by mass fraction, 10-20 parts of methyl methacrylate, 2-8 parts of polyethylene glycol diacrylate, 2-8 parts of butyl methacrylate, 2-5 parts of tert-butyl methacrylate, 2-10 parts of butyl acrylate, 3-10 parts of isooctyl acrylate, 0.8-1.5 parts of diacetone acrylamide, 1.0-2.0 parts of methacrylic acid, 0.03-0.08 parts of n-dodecyl mercaptan, 0.02-0.06 parts of sodium dodecyl benzene sulfonate, 0.05-0.1 parts of allyloxy alkyl polyoxyethylene ether sodium sulfate, 0.1-0.3 parts of potassium sorbate, 0.4-0.8 parts of adipic acid dihydrazide, 0.02-0.06 parts of ammonium persulfate, 0.01-0.05 parts of tert-butyl hydroperoxide, 0.01-0.05 parts of sodium ascorbate, 0.1-0.3 parts of white oil defoaming agent, 1.0-2.0 parts of ammonia water and 57-62 parts of pure water.

4. A process for the preparation of a water and oil repellent acrylate emulsion as claimed in claim 3, characterized in that, The method comprises the following steps: S1, add 35-45% of pure water to the reaction kettle, start stirring, add 25-35% of sodium dodecyl benzene sulfonate, disperse for 5-10 min, seal the reaction kettle, heat to 84-86℃, then vacuumize and break the vacuum with nitrogen; S2, add 10-15% of pure water to the high tank stirring kettle, start stirring at a speed of 60-80 r / min, add the remaining sodium dodecyl benzene sulfonate and allyloxy polyoxyethylene ether sodium sulfate, then stir at a speed of 100-120 r / min for 8-12 min, then add 40-60% of diacetone acrylamide, methacrylic acid and methyl methacrylate, as well as 10-90% of polyethylene glycol diacrylate, butyl methacrylate, tert-butyl methacrylate, butyl acrylate and isooctyl acrylate, then add n-dodecyl mercaptan, and stir for 30-40 min after the addition is completed to obtain a high tank emulsion for standby use; S3, when the temperature inside the reactor is 78-81℃, add 4-8% of the mass of the high tank emulsion, 2-4 min later, add 30-35% of the mass of ammonium persulfate, heat to 84-86℃ and keep for 8-12 min, then add the remaining high tank emulsion and the remaining ammonium persulfate, the dropwise adding time is 0.9-1.1h and 1.2-1.3h respectively, the temperature is controlled at 84-86℃ during the dropwise adding process, after the dropwise adding of ammonium persulfate is completed, continue to keep for 0.4-0.6h, then cool to 78-82℃, and adjust the PH to 8.5±0.2 by ammonia water, keep until the material in the reactor becomes a translucent liquid; S4, add all the remaining monomers to the high tank, stir until completely dissolved and uniform, to obtain a high tank monomer solution for standby; S5, when the reactor is cooled to 63-65℃, add 30-35% of the mass of the high tank monomer solution, stir for 13-17 min, when the temperature in the reactor is 55-60℃, add 10-15% of the mass of tert-butyl hydroperoxide, 1.5-2.5 min after the dropwise adding is completed, add 10-15% of the mass of sodium ascorbate, and the dropwise adding time is 4-5 min, keep for 18-22 min after the reactor is heated to the highest temperature; S6, repeat step S5 twice, respectively add 30-35% of the mass of the high tank monomer solution, and the remaining high tank monomer solution for reaction; S7, when the temperature in the reactor is cooled to 64-66℃, add the remaining tert-butyl hydroperoxide and sodium ascorbate at the same time, the dropwise adding time is 50-70 min; S8, when the temperature in the reactor is cooled to 44-46℃, add adipic acid dihydrazide, then add white oil defoaming agent and potassium sorbate, adjust the solid content to 38-43%, filter the discharge to obtain a waterproof and oil-proof acrylate emulsion; Among them, the ammonium persulfate, tert-butyl hydroperoxide and sodium ascorbate are all added in the form of aqueous solution of remaining pure water.

5. The method for preparing the waterproof and oil-resistant acrylate emulsion according to claim 4, characterized in that, In step S8, after filtering the discharge, 4-6% of acetyl citrate triethyl citrate microcapsules with chitosan as wall material are uniformly added to the emulsion based on the total mass of the emulsion.

6. Use of the water and oil repellent acrylate emulsion according to claim 3 for the preparation of wrapping 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.

7. Use of the water and oil repellent acrylate emulsion according to claim 3 for the preparation of wrapping paper, characterized in that, The specific steps of the application are as follows: taking the packaging base paper, fixing it on a coating machine, preparing a latex emulsion of false phytolacca acinosa seeds and coating the packaging base paper once, with a coating amount of 2-4 g / m 2 After the coating is completed, the coated paper is dried in an oven at 60-80 ℃ for 5-10 min, then the waterproof and oil-proof acrylic emulsion is taken to coat the coated paper again, with a coating amount of 4-6 g / m 2 After the coating is completed, 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.

8. Use according to claim 7, characterized in that, The specific operation for preparing the latex of fructus psidii seed is as follows: (1) Take the acetylated modified fructus psidii seed powder and add it to deionized water with 15-25 times the mass and under the condition of 200-300 rpm stirring, after adding, increase the stirring speed to 400-500 rpm and continue stirring for 1-2h, stand to defoam to obtain a fructus psidii seed hydration liquid; (2) Take sodium dodecyl polyoxyethylene ether sulfate and dissolve it in 10-12 times the mass of deionized water, then add a composite monomer, and high-speed shear for 15-20 min to form a pre-emulsion; (3) Prepare a reactor and heat it to 78-80℃, add 4-6% of the pre-emulsion based on the total mass of the pre-emulsion, and 30-35% of the ammonium persulfate solution based on the total mass of the ammonium persulfate solution, react for 15-20 min; (4) The remaining pre-emulsified liquid and ammonium sulfate solution are synchronously added into the reactor, the dropping time is controlled to be 2-2.5 h, the temperature is controlled to be 80±2℃, after the dropping is completed, the temperature is increased to 85±1℃ and kept for 1-1.5 h, and the reaction system is obtained; (5) When the reaction system is cooled to 38-40℃, the hydrated liquid of the physic nut seed gum is added under the state of stirring at 60-80 rpm, the pH is adjusted to 7.5-8.5 by using ammonia water, and the product is filtered, and the physic nut seed gum emulsion is obtained; The mass ratio of the acetylated modified physic nut seed gum powder, the sodium dodecyl polyoxyethylene ether sulfate, the composite monomer and the ammonium sulfate solution is 1:0.5-0.8:35-45:0.2-0.

4.

9. Use according to claim 8, characterized in that, The acetylated modified physic nut seed gum powder is prepared by the following steps: the commercially available physic nut seed gum powder is dispersed in 15-20 times of deionized water, the pH is adjusted to 8-8.5 by using NaOH, the stirring is activated for 20-30 min, 50-70% of the mass of the physic nut seed gum powder of acetic anhydride is added dropwise, after the dropping is completed, the stirring reaction is carried out at 25-30℃ for 1.5-2 h, the pH is adjusted to 6.5-7.0 by using HCl to terminate the reaction, and finally the precipitation, washing, drying and grinding are carried out to obtain the acetylated modified physic nut seed gum powder.

10. Use according to claim 8, characterized in that, The composite monomer is obtained by mixing butyl acrylate, isooctyl acrylate, methyl methacrylate and acrylic acid at a mass ratio of 25:12:8:1.

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