Cationic polymeric preservative emulsion and method of making same

Abstract

The application relates to a cationic polymer fresh-keeping emulsion and a preparation method thereof, which comprises the following raw materials in mass parts: 20-30 parts of cationic polymer, 2-3 parts of sodium carboxymethyl cellulose, 1-2 parts of polyoxyethylene ether nonionic surfactant, 0.05-0.1 part of polyhexamethyl guanidine salt, and water, and the water is used in an amount to make the solid content of the cationic polymer fresh-keeping emulsion 5-10%; the cationic polymer has a hyperbranched structure and comprises the following raw materials in mass parts: 45-65 parts of acrylic monomer, 7-11 parts of triethylene tetramine, 20-30 parts of bromoacetyl chloride, and 100-130 parts of long-chain alkyl tertiary amine. The cationic polymer prepared as the main component of the fresh-keeping emulsion is reasonably matched with other components to prepare the emulsion with excellent fresh-keeping performance, which can be simply sprayed on a fruit and vegetable fresh-keeping box or fresh-keeping paper to achieve excellent fresh-keeping effect. Moreover, the emulsion is durable and can maintain the fresh-keeping effect for a long time.

Description

Technical Field

[0001] This invention belongs to the field of preservatives, specifically relating to a cationic polymer preservative emulsion and its preparation method. Background Technology

[0002] As living standards improve, people have increasingly higher requirements for the preservation of fruits, vegetables, eggs, and other foods. The preservation of many fruits, vegetables, and other foods, such as apples, bananas, pears, peaches, cucumbers, and eggs, has become a problem. Improper storage or spoilage during transportation can seriously affect the quality of fruits and vegetables.

[0003] CN116970318A discloses a biomimetic preservation film coating for clean poultry eggs, comprising 1-10% sodium polyacrylate, 0.5-5‰ cationic polyacrylamide, 0.01-0.07‰ benzalkonium bromide, with the balance being water. For consumption, the preservation film coating is sprayed onto the surface of a washed egg and air-dried at 35°C to form a preservation film on the egg surface.

[0004] CN116746608A discloses a preservative solution comprising divalent metal cations, monovalent metal cations, and appropriate concentrations of metal ions such as calcium, magnesium, zinc, potassium, and sodium, each exerting its own activity. The preservative solution is applied to fruits and vegetables, or the fruits and vegetables are immersed in the preservative solution for treatment, forming a liquid film on the surface of the fruits and vegetables, thus acting as an air barrier. The synergistic effect of various metal ions at different concentrations results in fruits and vegetables treated with this solution having higher chlorophyll content, higher free radical scavenging rate, and higher antioxidant capacity.

[0005] CN116439280A discloses a fruit preservative comprising 0.5-2% chitosan, 0.5-2% acetic acid, 0.005-0.5% polyhexamethylene guanidine salt, with the balance being water. It exhibits good antibacterial effects against common Staphylococcus aureus and Escherichia coli.

[0006] CN108676117A discloses an aqueous self-crosslinking cationic copolymer emulsion, which is prepared by semi-continuous seed polymerization of cationic monomers, acrylate monomers and self-crosslinking monomers to obtain an antibacterial emulsion with long antibacterial effect, good water resistance, and good anti-mildew and antibacterial properties even after 20,000 continuous rinsing.

[0007] Currently, existing technologies mostly involve spraying preservatives onto fruits and vegetables or preparing antibacterial preservative films for coating. However, while spraying preservatives directly onto fruits and vegetables has a good preservation effect, it also leaves a film of preservative liquid on the surface of the fruits and vegetables, which may pose certain safety risks if consumed. Methods for making PE or other preservative films require the production of polymer films, which are costly. Summary of the Invention

[0008] To address the current lack of preservatives for fruits, vegetables, and eggs that can be directly sprayed onto ordinary paper safes to achieve excellent preservation results, this invention provides a cationic preservative emulsion and its preparation method. When used, the preservative emulsion is sprayed onto the surface of paper safes commonly used for storing fruits, vegetables, and eggs, or onto paper trays for holding eggs, achieving satisfactory preservation results. The cationic preservative emulsion provided by this invention can maintain the freshness of fruits for more than 7 days at room temperature and eggs for more than 50 days at room temperature, meeting the daily food preservation needs of residents or providing a cost-effective preservation measure for fruits and vegetables during logistics transportation. It has strong industrial applicability and commercial value. This invention solves the above-mentioned technical problems through the following technical solutions.

[0009] A cationic polymer preservative emulsion comprises the following raw materials in parts by weight: 20-30 parts cationic polymer, 2-3 parts sodium carboxymethyl cellulose, 1-2 parts polyoxyethylene ether nonionic surfactant, 0.05-0.1 parts polyhexamethylene guanidine salt, and water, wherein the amount of water is such that the solid content of the cationic polymer preservative emulsion is 5-10%; the cationic polymer has a hyperbranched structure and comprises the following raw materials in parts by weight: 45-65 parts acrylic monomer, 7-11 parts triethylenetetramine, 20-30 parts bromoacetyl chloride, and 100-130 parts long-chain alkyl tertiary amine, wherein the acrylic monomer includes (meth)acrylate C1-4 alkyl esters, hydroxyl-containing acrylates, epoxy-containing acrylates, and polyfunctional acrylates.

[0010] Furthermore, the cationic polymer is prepared by a method comprising the following steps:

[0011] (S1) (Meth)acrylate C1-4 alkyl ester, hydroxyl-containing acrylate, epoxy-containing acrylate, and polyfunctional acrylate are mixed evenly in a certain proportion to form a monomer mixture.

[0012] (S2) Add 100 parts by weight of water, 2-3 parts by weight of emulsifier, 0.1-0.3 parts by weight of bicarbonate, 5-10 parts by weight of the monomer mixture from step (S1), and 0.2-0.3 parts by weight of chain transfer agent to the reactor. Mix well to form an emulsion. Under a protective atmosphere, add an aqueous solution containing 0.01-0.03 parts by weight of water-soluble initiator, and heat to initiate polymerization to obtain a prepolymer emulsion.

[0013] (S3) Maintain the reaction temperature and slowly add an aqueous solution containing 0.1-0.2 parts by mass of water-soluble initiator and 40-55 parts by mass of monomer mixture from step (S1) to the prepolymer emulsion obtained in step (S2). After the addition is complete, continue the reaction for 1-2 hours to obtain a polymer emulsion.

[0014] (S4) Add 0.4-0.6 parts by mass of triphenylphosphine and 7-11 parts by mass of triethylenetetramine to the system in step (S3), react at room temperature for 1-2 hours, then raise the temperature to 90-110℃ and continue the reaction for 3-5 hours; after cooling to room temperature, add 20-30 parts by mass of bromoacetyl chloride and 60-80 parts by mass of pyridine under an ice-salt bath, and react for 50-70 hours;

[0015] (S5) Add 100-130 parts by mass of long-chain alkyl tertiary amine to the material in step (S4), react at 60-80℃ for 24-36h, cool to room temperature, add toluene, filter, wash the product to obtain cationic polymer.

[0016] Existing technologies often use cationic polymers obtained by copolymerizing cationic monomers with other monomers to produce cationic polymer preservative emulsions. However, the preservation / antibacterial effects are limited, possibly due to issues such as the polymerization competition rate during copolymerization, which prevents the cationic antibacterial effect from being fully realized. This invention involves the seed emulsion polymerization of acrylate monomers, followed by reaction with a secondary amine to prepare a hyperbranched polymer with hydroxyl-terminated groups. This polymer is then reacted with bromoacetyl chloride to obtain a hyperbranched polymer with bromine-terminated groups. Finally, the bromine-terminated groups are quaternized to obtain a cationic polymer emulsion. The quaternary ammonium salt is evenly distributed, and the emulsion is stable, providing long-lasting preservation and antibacterial effects. Direct spraying onto a food storage box or preservation paper achieves satisfactory preservation results. At room temperature, fruits and vegetables can be preserved for 5-10 days, and eggs for over 50 days, significantly extending the shelf life of fruits, vegetables, poultry, eggs, and other foods.

[0017] Furthermore, the polyoxyethylene ether nonionic surfactant is selected from at least one of pentadecyl fatty alcohol polyoxyethylene ethers (such as AEO-9, AEO-10, AEO-15), coconut oil-based monoethanolamide polyoxyethylene ethers, and nonylphenol polyoxyethylene ethers (such as NPE-7, NPE-8, NPE-10, NPE-15). The inventors have discovered that surfactants containing polyoxyethylene ethers not only provide excellent emulsifying ability for the preservative emulsion of this invention, resulting in a stable emulsion, but also help enhance the emulsion's preservation ability. The inventors speculate that this may be related to the lipophilicity of bacteria / molds.

[0018] Further, in step (S1), the mass ratio of (meth)acrylate C1-4 alkyl ester, hydroxyl-containing acrylate, epoxy-containing acrylate, and multifunctional acrylate is 40-60:12-15:2-3:0.5-0.7; even further, the (meth)acrylate C1-4 alkyl ester is selected from at least one of (meth)acrylate, (meth)acrylate, (meth)acrylate, (meth)acrylate, and (meth)acrylate; the hydroxyl-containing acrylate is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, and 2,3-dihydroxypropyl acrylate; the epoxy-containing acrylate is selected from at least one of glycidyl acrylate and glycidyl methacrylate; and the multifunctional acrylate is selected from at least one of polyethylene glycol diacrylate, pentaerythritol triacrylate, and glyceryl triacrylate.

[0019] Preferably, the hydroxyl-containing acrylate is selected from a compound of acrylate containing one hydroxyl group and propyl 2,3-dihydroxyacrylate in a mass ratio of 2-2.7:1, and the acrylate containing one hydroxyl group is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate. The inventors have discovered that using the above-mentioned compounded hydroxyl-containing acrylate as a raw material, the resulting cationic polymer achieves an optimal balance between antibacterial properties and stability.

[0020] Further, in step (S2), the water-soluble initiator is selected from at least one of sodium persulfate, potassium persulfate, and ammonium persulfate; the emulsifier is a mixture of cationic and nonionic emulsifiers in a mass ratio of 1-2:1-2; the cationic emulsifier is selected from at least one of dodecyltrimethylammonium bromide, dodecyldimethylbenzylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide; the nonionic emulsifier is selected from at least one of OP-7, OP-9, OP-10, Span40, and Span60; the chain transfer agent is selected from at least one of dodecyl mercaptan, n-octyl mercaptan, isooctyl mercaptoacetate, and octadecyl mercaptan; the bicarbonate is selected from at least one of sodium bicarbonate and potassium bicarbonate; the protective atmosphere is nitrogen and / or argon; the polymerization is initiated by heating to 60-80°C and reacting for 0.5-1 h; the emulsion turns blue, at which point a prepolymer seed emulsion is obtained.

[0021] Furthermore, in step (S3), the aqueous solution of the water-soluble initiator has a mass concentration of 5-10 wt%, and the slow addition is completed over 3-5 hours.

[0022] Further, in step (S5), the long-chain alkyl tertiary amine is selected from at least one of dodecyl dimethylamine, tetradecyl dimethylamine, hexadecyl dimethylamine, and bishexadecyl methylamine.

[0023] The present invention also provides a method for preparing the cationic polymer preservation emulsion, comprising the following steps: mixing the cationic polymer sodium carboxymethyl cellulose, polyoxyethylene ether nonionic surfactant, polyhexamethylene guanidine salt and water under stirring conditions to obtain the cationic polymer preservation emulsion.

[0024] This invention also provides the use of the cationic polymer preservative emulsion in food preservation, wherein the cationic polymer preservative emulsion is sprayed onto food storage boxes, food storage paper, and food storage paper trays, with a spraying amount of 100-200 ml per kg of cationic polymer preservative emulsion when the solid content of the cationic polymer preservative emulsion is 3-5%. 2 Food storage boxes, food storage paper, or food storage paper trays.

[0025] The superior effects of this invention are as follows:

[0026] I. This invention uses a cationic polymer as the main component of a preservative emulsion, and combines it with other ingredients in a reasonable formulation to create an emulsion with excellent preservation properties. It can be simply sprayed onto fruit and vegetable storage boxes or preservation paper to achieve excellent preservation results. Furthermore, it is durable and can maintain its preservation effect for a long time.

[0027] Second, the emulsion of this invention has good stability and high solid content. It can be diluted to a suitable solid content before use, which facilitates production, storage and transportation. Attached Figure Description

[0028] Figure 1 These are photos of tomatoes used in Example 1 and the reference example for preservation testing.

[0029] Figure 2 This is a photograph of egg liquid after preservation testing, which is Example 1, Comparative Example 1, and Reference Example. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. The following embodiments are provided to better understand this invention, but do not limit the invention. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods.

[0031] Preparation Example 1

[0032] (S1) 40 parts by weight of methyl methacrylate, 15 parts by weight of hydroxyl-containing acrylate (a mixture of hydroxyethyl acrylate and 2,3-dihydroxyacrylate in a mass ratio of 2.7:1), 3 parts by weight of glycidyl acrylate, and 0.5 parts by weight of pentaerythritol triacrylate are mixed evenly to form a monomer mixture.

[0033] (S2) Add 100 parts by weight of water, 3 parts by weight of emulsifier (hexadecyltrimethylammonium bromide and OP-9 in a mass ratio of 1:1), 0.2 parts by weight of sodium bicarbonate, 10 parts by weight of the monomer mixture from step (S1), and 0.2 parts by weight of chain transfer agent dodecyl mercaptan to the reactor. Mix well to form an emulsion. Under a nitrogen atmosphere, add 0.2 parts by weight of 10wt% ammonium persulfate aqueous solution, heat to 70°C to initiate polymerization, and polymerize for 0.5 h to obtain a prepolymer emulsion.

[0034] (S3) Maintain 70°C and slowly add 1.5 parts by mass of 10 wt% ammonium persulfate aqueous solution and 40 parts by mass of the monomer mixture from step (S1) to the prepolymer emulsion obtained in step (S2). After the addition is complete, continue the reaction for 2 hours to obtain a polymer emulsion.

[0035] (S4) Add 0.5 parts by mass of triphenylphosphine and 7 parts by mass of triethylenetetramine to the system in step (S3), react at room temperature for 1 h, then raise the temperature to 95 °C and continue the reaction for 5 h; after cooling to room temperature, add 20 parts by mass of bromoacetyl chloride and 60 parts by mass of pyridine under an ice-salt bath, and react for 60 h.

[0036] (S5) Add 100 parts by mass of dihexadecanylmethylamine to the material in step (S4), react at 60°C for 36 h, cool to room temperature, add toluene, filter, wash the product with toluene and acetone in sequence, and dry to obtain a cationic polymer.

[0037] Preparation Example 2

[0038] (S1) 60 parts by weight of butyl methacrylate, 12 parts by weight of hydroxyl acrylate (a mixture of hydroxyethyl acrylate and propyl 2,3-dihydroxyacrylate in a mass ratio of 2:1), 3 parts by weight of glycidyl acrylate, and 0.7 parts by weight of glyceryl triacrylate are mixed evenly to form a monomer mixture.

[0039] (S2) Add 100 parts by weight of water, 3 parts by weight of emulsifier (hexadecyltrimethylammonium bromide and OP-9 in a mass ratio of 1:1), 0.2 parts by weight of sodium bicarbonate, 10 parts by weight of the monomer mixture from step (S1), and 0.2 parts by weight of chain transfer agent dodecyl mercaptan to the reactor. Mix well to form an emulsion. Under a nitrogen atmosphere, add 0.3 parts by weight of 10wt% ammonium persulfate aqueous solution. Heat to 70°C to initiate polymerization. Polymerize for 1 hour to obtain a prepolymer emulsion.

[0040] (S3) Maintain 70°C and slowly add 2 parts by mass of 10 wt% ammonium persulfate aqueous solution and 55 parts by mass of monomer mixture from step (S1) to the prepolymer emulsion obtained in step (S2). After the addition is complete, continue the reaction for 2 hours to obtain polymer emulsion.

[0041] (S4) Add 0.6 parts by mass of triphenylphosphine and 11 parts by mass of triethylenetetramine to the system in step (S3), react at room temperature for 1 h, then raise the temperature to 95 °C and continue the reaction for 5 h; after cooling to room temperature, add 30 parts by mass of bromoacetyl chloride and 80 parts by mass of pyridine under an ice-salt bath, and react for 60 h.

[0042] (S5) Add 120 parts by mass of dihexadecanylmethylamine to the material in step (S4), react at 60°C for 36 h, cool to room temperature, add toluene, filter, wash the product with toluene and acetone in sequence, and dry to obtain a cationic polymer.

[0043] Preparation Example 3

[0044] The other conditions are the same as in Preparation Example 1, except that in step (S1), all hydroxy acrylates are hydroxyethyl acrylates.

[0045] Preparation Example 4

[0046] The other conditions are the same as in Preparation Example 1, except that in step (S1), all hydroxy acrylates are propyl 2,3-dihydroxyacrylate.

[0047] Example 1

[0048] 20 parts by weight of the cationic polymer prepared in Example 1, 2 parts by weight of sodium carboxymethyl cellulose, 2 parts by weight of AEO-10, 0.05 parts by weight of polyhexamethylene guanidine salt, and water were mixed and prepared into an emulsion under stirring conditions. The amount of water used was such that the solid content of the cationic polymer preservation emulsion was 10%.

[0049] Example 2

[0050] 30 parts by mass of the cationic polymer prepared in Example 2, 3 parts by mass of sodium carboxymethyl cellulose, 2 parts by mass of NPE-8, 0.05 parts by mass of polyhexamethylene guanidine salt, and water were mixed and stirred to form an emulsion. The amount of water used was such that the solid content of the cationic polymer preservation emulsion was 10%.

[0051] Example 3

[0052] The other conditions were the same as in Example 1, except that the cationic polymer was prepared in Preparation Example 3.

[0053] Example 4

[0054] The other conditions were the same as in Example 1, except that the cationic polymer was prepared in Preparation Example 4.

[0055] Comparative Example 1

[0056] The other conditions are the same as in Example 1, except that the cationic polymer is polyquaternary ammonium salt GAP121.

[0057] Application Example 1

[0058] The emulsions from the above examples and comparative examples were subjected to the following performance tests, and the results are shown in Table 1 below:

[0059] Emulsion stability testing involves observing the emulsion after the experiment. If there is no obvious layering, oil floating, or emulsion breaking, the stability is considered to be qualified.

[0060] Centrifugal stability was determined by centrifuging at 5000 rpm for 30 minutes and observing the emulsion condition; 60℃ storage stability was determined by storing the emulsion at 60℃ in a sealed, light-protected environment for 10 days.

[0061] Table 1. Emulsion stability performance test

[0062]

[0063]

[0064] Application Example 2

[0065] The antibacterial properties of the emulsion obtained in the examples were tested according to GB / T 21866-2008. The antibacterial durability test involved irradiating the paint film with a 30W, 253nm UV lamp at a distance of 1 meter for 100 hours, followed by a retest of the antibacterial rate. The antifungal properties were tested according to GB / T 1741-2007. The antifungal durability test involved rinsing the film with tap water 100 times, followed by a retest of the antifungal properties. The results are shown in Table 2 below.

[0066] Table 2. Antibacterial Performance Test of Emulsions

[0067]

[0068] Application Example 3

[0069] The emulsions from the examples and comparative examples were diluted with deionized water to a solid content of 3%, and sprayed onto fruit preservation cartons / egg trays / preservative paper. The spraying amount was 1 kg of emulsion per 100 m². 2 Food storage cardboard box, 200m 2Eggs were placed in paper trays / cling film in a cool, ventilated place for 2 days. In the remaining samples, no treatment was applied. Preservation tests were conducted on peaches, eggs, and tomatoes. Peaches were placed in cling film boxes, eggs in egg trays, and tomatoes covered with cling film. Preservation conditions were 25±1℃, 60-65% RH, and protection from light. 100 samples of each preservation item were tested. The preservation test period for peaches was 8 days, for tomatoes 7 days, and for eggs 50 days. Peaches were considered unqualified if they showed any of the following: mold spots, rot, or hair growth. Tomatoes were considered unqualified if they showed any of the following: mold spots, softening, rot, or the growth of clusters of green to dark green mold. Eggs were considered unqualified if the yolk was runny, stuck to the shell, or emitted a putrid odor. The percentage of qualified samples out of 100 samples was calculated as the preservation qualification rate, and the results are shown in Table 3 below.

[0070] Table 3 Preservation effect test

[0071] lotion peach tomato egg Example 1 92％ 86％ 95％ Example 2 95％ 90％ 96％ Example 3 90％ 82％ 89％ Example 4 92％ 88％ 87％ Comparative Example 1 71％ 54％ 72％ Reference example 32％ 15％ 53％

[0072] Figure 1 These are photographs of tomatoes used in preservation tests for Example 1 and the reference example. The left image shows the tomatoes treated with the emulsion in Example 1, and the right image shows the reference example without emulsion treatment.

[0073] Figure 2 These are photographs of egg liquid after preservation tests for Example 1, Comparative Example 1, and Reference Example. The left image shows the emulsion treatment in Example 1, the middle image shows the emulsion treatment in Comparative Example 1, and the right image shows the reference example without emulsion treatment.

Claims

1. A cationic polymer preservative emulsion, characterized in that, The mixture comprises the following raw materials in parts by weight: 20-30 parts cationic polymer, 2-3 parts sodium carboxymethyl cellulose, 1-2 parts polyoxyethylene ether nonionic surfactant, 0.05-0.1 parts polyhexamethylene guanidine salt, and water, wherein the amount of water is such that the solid content of the cationic polymer preservative emulsion is 5-10%; the cationic polymer has a hyperbranched structure and comprises the following raw materials in parts by weight: 45-65 parts acrylic monomer, 7-11 parts triethylenetetramine, 20-30 parts bromoacetyl chloride, and 100-130 parts long-chain alkyl tertiary amine, wherein the acrylic monomer includes (meth)acrylate C1-4 alkyl esters, hydroxyl-containing acrylates, epoxy-containing acrylates, and polyfunctional acrylates; the cationic polymer is prepared by a method comprising the following steps: (S1) (Meth)acrylate C1-4 alkyl ester, hydroxyl-containing acrylate, epoxy-containing acrylate, and polyfunctional acrylate are mixed evenly in a certain proportion to form a monomer mixture. (S2) Add 100 parts by weight of water, 2-3 parts by weight of emulsifier, 0.1-0.3 parts by weight of bicarbonate, 5-10 parts by weight of the monomer mixture from step (S1), and 0.2-0.3 parts by weight of chain transfer agent to the reactor. Mix well to form an emulsion. Under a protective atmosphere, add an aqueous solution containing 0.01-0.03 parts by weight of water-soluble initiator. Heat the mixture to initiate polymerization and obtain a prepolymer emulsion. (S3) Maintain the reaction temperature and slowly add an aqueous solution containing 0.1-0.2 parts by mass of water-soluble initiator and 40-55 parts by mass of monomer mixture from step (S1) to the prepolymer emulsion obtained in step (S2). After the addition is complete, continue the reaction for 1-2 hours to obtain a polymer emulsion. (S4) Add 0.4-0.6 parts by mass of triphenylphosphine and 7-11 parts by mass of triethylenetetramine to the system in step (S3), react at room temperature for 1-2 hours, then raise the temperature to 90-110℃ and continue the reaction for 3-5 hours; after cooling to room temperature, add 20-30 parts by mass of bromoacetyl chloride and 60-80 parts by mass of pyridine under an ice-salt bath, and react for 50-70 hours; (S5) Add 100-130 parts by mass of long-chain alkyl tertiary amine to the material in step (S4), react at 60-80℃ for 24-36h, cool to room temperature, add toluene, filter, wash the product to obtain cationic polymer.

2. The cationic polymer preservative emulsion according to claim 1, characterized in that, The polyoxyethylene ether nonionic surfactant is selected from at least one of pentadecyl fatty alcohol polyoxyethylene ether, coconut oil-based monoethanolamide polyoxyethylene ether, and nonylphenol polyoxyethylene ether.

3. The cationic polymer preservative emulsion according to claim 1, characterized in that, In step (S1), the mass ratio of (meth)acrylate C1-4 alkyl ester, hydroxyl-containing acrylate, epoxy-containing acrylate, and multifunctional acrylate is 40-60:12-15:2-3:0.5-0.

7.

4. The cationic polymer preservative emulsion according to claim 3, characterized in that, The (meth)acrylate C1-4 alkyl ester is selected from at least one of (meth)acrylate, (meth)acrylate, (meth)acrylate, and (meth)acrylate; the hydroxyl-containing acrylate is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, and 2,3-dihydroxypropyl acrylate; the epoxy-containing acrylate is selected from at least one of glycidyl acrylate and glycidyl methacrylate; the polyfunctional acrylate is selected from at least one of polyethylene glycol diacrylate, pentaerythritol triacrylate, and glyceryl triacrylate.

5. The cationic polymer preservative emulsion according to claim 1, characterized in that, The hydroxyl-containing acrylate is a compound of an acrylate containing one hydroxyl group and propyl 2,3-dihydroxyacrylate in a mass ratio of 2-2.7:1; the acrylate containing one hydroxyl group is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, and hydroxybutyl acrylate.

6. The cationic polymer preservative emulsion according to claim 1, characterized in that, In step (S2), the water-soluble initiator is selected from at least one of sodium persulfate, potassium persulfate, and ammonium persulfate; the emulsifier is a mixture of cationic and nonionic emulsifiers in a mass ratio of 1-2:1-2; the cationic emulsifier is selected from at least one of dodecyltrimethylammonium bromide, dodecyldimethylbenzylammonium bromide, tetradecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide; the nonionic emulsifier is selected from at least one of OP-7, OP-9, OP-10, Span40, and Span60; the chain transfer agent is selected from at least one of dodecyl mercaptan, n-octyl mercaptan, isooctyl mercaptoacetate, and octadecyl mercaptan; the bicarbonate is selected from at least one of sodium bicarbonate and potassium bicarbonate; the protective atmosphere is nitrogen and / or argon; the polymerization is initiated by heating to 60-80°C and reacting for 0.5-1 h; the emulsion turns blue, at which point a prepolymer seed emulsion is obtained.

7. The cationic polymer preservative emulsion according to claim 1, characterized in that, In step (S3), the aqueous solution of the water-soluble initiator has a mass concentration of 5-10 wt%, and the slow addition is completed over 3-5 hours.

8. The cationic polymer preservative emulsion according to claim 1, characterized in that, In step (S5), the long-chain alkyl tertiary amine is selected from at least one of dodecyl dimethylamine, tetradecyl dimethylamine, hexadecyl dimethylamine, and bishexadecyl methylamine.

9. A method for preparing the cationic polymer preservative emulsion according to any one of claims 1-8, characterized in that, The process includes the following steps: mixing cationic polymer, sodium carboxymethyl cellulose, polyoxyethylene ether nonionic surfactant, polyhexamethylene guanidine salt, and water under stirring conditions to obtain cationic polymer preservation emulsion.

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