Rosin-based reactive emulsifier and preparation method thereof

Abstract

The invention relates to the technical field of emulsifiers, in particular to a rosin-based reactive emulsifier and a preparation method thereof. The preparation method comprises the following steps: step 1, dispersing ethylene glycol chitosan in deionized water to obtain an ethylene glycol chitosan aqueous solution; the preparation method comprises the following steps: adding an octenyl succinic anhydride ethanol water solution into an ethylene glycol chitosan water solution, adjusting the pH value to 8.3-8.5 by using a sodium hydroxide solution, reacting at 30-40 DEG C for 22-24 hours, dialyzing and freeze-drying to obtain modified ethylene glycol chitosan; step 2, mixing maleated rosin, modified ethylene glycol chitosan and stannous oxalate under the protection of nitrogen, reacting at 240-270 DEG C for 4-8 hours, cooling to room temperature, and performing rotary evaporation to obtain an intermediate; and 3, uniformly mixing the intermediate, a cationic monomer and absolute ethyl alcohol, reacting at 30-50 DEG C for 6-8 hours, and carrying out rotary evaporation to obtain the rosin-based reactive emulsifier.

Description

Technical Field

[0001] The present invention relates to the technical field of emulsifiers, and particularly to a rosin-based reactive emulsifier and a preparation method thereof. Background Art

[0002] In many industrial fields, such as coatings, inks, adhesives and other industries, emulsifiers play a crucial role. Emulsifiers can make the immiscible oil phase and water phase form a stable emulsion system. For example, in the coating industry, a good emulsifier can evenly disperse oil-based components such as resins in an aqueous system, thus meeting the development needs of environmentally friendly waterborne coatings. With the increasing awareness of environmental protection among people, the market share of waterborne coatings is continuously expanding, and the demand for efficient emulsifiers is also becoming increasingly urgent.

[0003] Emulsion polymerization uses water as the dispersion medium, with a relatively fast reaction rate and mild conditions, and can quickly obtain high-molecular-weight products. However, the surface of traditional latex particles physically adsorbs a layer of surfactant, and the residual surfactant is difficult to remove, which affects the product performance and is likely to migrate to the film surface during film formation, affecting the film performance. Reactive emulsifiers, also known as polymerizable emulsifiers, can be divided into two types: one is a monomer with emulsifying properties containing double bonds, and the other is an initiator that can play an initiating role. In the emulsion polymerization reaction system, the former participates in the reaction as a comonomer, and the latter plays the role of an initiator. They not only have the basic function of emulsifiers, that is, emulsifying the polymerization system, but also can react with other monomers through copolymerization or initiation polymerization and be directly incorporated into the polymer chain. The surfactant molecules are firmly grafted onto the latex particles by covalent bonds, reducing the surface tension of the polymer itself, effectively reducing the drawback of surfactant migration from the surface of latex particles to the film surface during film formation, improving the stability and solid content of latex particles, and at the same time not affecting the polymerization reaction rate.

[0004] At the same time, some traditional emulsifiers (such as sodium dodecylbenzenesulfonate) may have problems such as poor biodegradability and are difficult to meet the requirements of scenarios with high environmental protection requirements. In contrast, rosin, as a natural renewable resource, is mainly derived from the resins of coniferous trees such as pine trees, and its molecules contain various active functional groups, such as carboxyl groups and hydroxyl groups, etc., and can endow emulsifiers with special functions through chemical modification.

[0005] Therefore, we propose a rosin-based reactive emulsifier and a preparation method thereof. Summary of the Invention

[0006] The purpose of the present invention is to provide a rosin-based reactive emulsifier and a preparation method thereof to solve the problems raised in the prior art.

[0007] To achieve the above purpose, the present invention provides the following technical solutions: A preparation method of a rosin-based reactive emulsifier comprises the following steps: Step 1: Dispersing glycol chitosan in deionized water to obtain an aqueous glycol chitosan solution; adding an aqueous ethanol solution of octenyl succinic anhydride to the aqueous glycol chitosan solution, adjusting the pH to 8.3 - 8.5 with a sodium hydroxide solution, reacting at 30 - 40 °C for 22 - 24 h, followed by dialysis and freeze-drying to obtain modified glycol chitosan; Step 2: Under nitrogen protection, mixing maleic rosin, modified glycol chitosan and stannous oxalate, reacting at 240 - 270 °C for 4 - 8 h, cooling to room temperature, and performing rotary evaporation to obtain an intermediate; Step 3: Mixing the intermediate, a cationic monomer and absolute ethanol uniformly, reacting at 30 - 50 °C for 6 - 8 h, and performing rotary evaporation to obtain the rosin-based reactive emulsifier.

[0008] Further, in Step 1, the concentration of the aqueous glycol chitosan solution is 1 - 3 wt%, and the concentration of the aqueous ethanol solution of octenyl succinic anhydride is 10 - 12 wt%.

[0009] Further, in Step 1, the dosage of the aqueous ethanol solution of octenyl succinic anhydride is 0.1 - 0.2 times the mass of the aqueous glycol chitosan solution.

[0010] Further, in Step 2, the mass ratio of maleic rosin, modified glycol chitosan and stannous oxalate is 1:(1.5 - 2.5):(0.01 - 0.03).

[0011] Further, in Step 3, the mass ratio of the intermediate, the cationic monomer and absolute ethanol is 1:(1 - 3):(10 - 12).

[0012] Further, the preparation method of the cationic monomer is as follows: Mixing epichlorohydrin and toluene uniformly, adding dimethylaminopropyl acrylamide, reacting at 60 - 70 °C for 2 - 4 h, and performing rotary evaporation to obtain the cationic monomer.

[0013] Further, the mass ratio of epichlorohydrin, dimethylaminopropyl acrylamide and toluene is 1:(1.7 - 2.0):(3 - 5).

[0014] Compared with the prior art, the beneficial effects of the present invention are: The present invention discloses a rosin-based reactive emulsifier and its preparation method. By carrying out partial hydrophobic modification of water-soluble glycol chitosan (GC) with octenyl succinic anhydride, introducing double bonds and hydrophobic groups, a amphiphilic substance containing both lipophilic groups and hydrophilic groups is obtained, namely modified glycol chitosan. This amphiphilic structure enables it to well adapt to different oil-phase and water-phase systems, and has good compatibility with both the oil phase and the water phase, thus forming a stable adsorption layer at the oil-water interface, playing the roles of emulsification, dispersion and stabilization, effectively preventing the demulsification and stratification of the emulsion, and prolonging the shelf life of the emulsion; Then, using maleic rosin and modified glycol chitosan as raw materials, esterification reaction is carried out under a nitrogen atmosphere through the action of a catalyst, introducing the amphiphilic structure into maleic rosin, not only enhancing the lipophilicity of the emulsifier, but also retaining a certain hydrophilicity, so that it can effectively stabilize the oil-water interface during the emulsification process, significantly improving the emulsification effect; Finally, a cationic monomer containing double bonds and epoxy groups is prepared from epichlorohydrin and dimethylaminopropyl acrylamide. By grafting cationic groups on the molecular chain of maleic rosin, the steric hindrance effect and salt resistance between molecular chains are enhanced, the surface or interfacial tension can be significantly reduced, the emulsification effect is improved, and it can be applied to a wider range of emulsification systems. Finally, a rosin-based reactive emulsifier containing a large number of double bonds is prepared, which has high reaction activity. These double bonds can copolymerize with other substances containing double bonds, or undergo addition reactions with active functional groups, etc. This enables the emulsifier to form a more compact network structure in the curing system, thereby improving the mechanical properties and weather resistance of the material. Specific embodiments

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0016] In this embodiment, maleic rosin: model 115, sourced from Wuhan Jiyesheng Chemical Co., Ltd.; glycol chitosan: model S41671, sourced from Shanghai Yuanye Bio-Technology Co., Ltd.; octenyl succinic anhydride: CAS number 26680-54-6; dimethylaminopropyl acrylamide: CAS number 3845-76-9.

[0017] Example 1: A preparation method of a rosin-based reactive emulsifier, including the following processes: Step 1: Disperse 150 g of glycol chitosan in deionized water to obtain a 1 wt% glycol chitosan aqueous solution; add a 10 wt% aqueous ethanol solution of octenyl succinic anhydride to the glycol chitosan aqueous solution, adjust the pH to 8.3 with sodium hydroxide solution, react at 30 °C for 22 h, and after dialysis and freeze-drying, obtain modified glycol chitosan; the dosage of the aqueous ethanol solution of octenyl succinic anhydride is 0.1 times the mass of the glycol chitosan aqueous solution. Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 150 g of modified glycol chitosan and 1 g of stannous oxalate, react at 240 °C for 8 h, cool to room temperature, and after rotary evaporation, obtain an intermediate. Step 3: Mix 100 g of the intermediate, 100 g of cationic monomer and 1000 g of absolute ethanol evenly, react at 30 °C for 8 h, and after rotary evaporation, obtain a rosin-based reactive emulsifier. The preparation method of the cationic monomer is as follows: Mix 100 g of epichlorohydrin and 300 g of toluene evenly, add 170 g of dimethylaminopropyl acrylamide, react at 60 °C for 2 h, and after rotary evaporation, obtain the cationic monomer. An application of a rosin-based reactive emulsifier includes the following process: Take 1 g of the prepared rosin-based reactive emulsifier, dissolve it in 50 g of deionized water, heat it to 70 °C under nitrogen protection, add 30 g of a 1% aqueous solution of ammonium persulfate with stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7, and obtain an emulsion.

[0018] Example 2: A preparation method of a rosin-based reactive emulsifier includes the following process: Step 1: Disperse 100 g of glycol chitosan in deionized water to obtain a 1.5 wt% glycol chitosan aqueous solution; add a 10.5 wt% aqueous ethanol solution of octenyl succinic anhydride to the glycol chitosan aqueous solution, adjust the pH to 8.4 with sodium hydroxide solution, react at 35 °C for 23 h, and after dialysis and freeze-drying, obtain modified glycol chitosan; the dosage of the aqueous ethanol solution of octenyl succinic anhydride is 0.12 times the mass of the glycol chitosan aqueous solution. Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 180 g of modified glycol chitosan and 1.5 g of stannous oxalate, react at 250 °C for 7 h, cool to room temperature, and after rotary evaporation, obtain an intermediate. Step 3: Mix 100 g of the intermediate, 150 g of cationic monomer and 1050 g of absolute ethanol evenly, react at 40 °C for 7 h, and after rotary evaporation, obtain a rosin-based reactive emulsifier. The preparation method of the cationic monomer is as follows: Mix 150 g of epichlorohydrin and 525 g of toluene evenly, add 270 g of dimethylaminopropyl acrylamide, react at 65 °C for 3 h, and obtain the cationic monomer through rotary evaporation; The application of a rosin-based reactive emulsifier includes the following process: Take 1 g of the prepared rosin-based reactive emulsifier, dissolve it in 50 g of deionized water, heat it to 70 °C under nitrogen protection, add 30 g of 1% ammonium persulfate aqueous solution while stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate, and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7 to obtain an emulsion.

[0019] Example 3: A preparation method of a rosin-based reactive emulsifier includes the following process: Step 1: Disperse 200 g of glycol chitosan in deionized water to obtain a 2 wt% glycol chitosan aqueous solution; add an 11 wt% ethanol aqueous solution of octenyl succinic anhydride to the glycol chitosan aqueous solution, adjust the pH = 8.4 using sodium hydroxide solution, react at 35 °C for 24 h, and obtain modified glycol chitosan through dialysis and freeze-drying; the dosage of the ethanol aqueous solution of octenyl succinic anhydride is 0.15 times the mass of the glycol chitosan aqueous solution; Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 200 g of modified glycol chitosan, and 1.8 g of stannous oxalate, react at 255 °C for 6 h, cool to room temperature, and obtain an intermediate through rotary evaporation; Step 3: Mix 100 g of the intermediate, 200 g of the cationic monomer, and 1100 g of absolute ethanol evenly, react at 40 °C for 7 h, and obtain the rosin-based reactive emulsifier through rotary evaporation; The preparation method of the cationic monomer is as follows: Mix 200 g of epichlorohydrin and 700 g of toluene evenly, add 360 g of dimethylaminopropyl acrylamide, react at 65 °C for 3 h, and obtain the cationic monomer through rotary evaporation; The application of a rosin-based reactive emulsifier includes the following process: Take 1 g of the prepared rosin-based reactive emulsifier, dissolve it in 50 g of deionized water, heat it to 70 °C under nitrogen protection, add 30 g of 1% ammonium persulfate aqueous solution while stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate, and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7 to obtain an emulsion.

[0020] Example 4: A preparation method of a rosin-based reactive emulsifier includes the following process: Step 1: Disperse 220 g of glycol chitosan in deionized water to obtain a 2.5 wt% glycol chitosan aqueous solution; add an 11.5 wt% ethanol aqueous solution of octenyl succinic anhydride to the glycol chitosan aqueous solution, adjust the pH to 8.5 using sodium hydroxide solution, react at 35 °C for 24 h, and after dialysis and freeze-drying, obtain modified glycol chitosan; the amount of the ethanol aqueous solution of octenyl succinic anhydride is 0.18 times the mass of the glycol chitosan aqueous solution. Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 220 g of modified glycol chitosan, and 2 g of stannous oxalate, react at 260 °C for 6 h, cool to room temperature, and after rotary evaporation, obtain an intermediate. Step 3: Mix 100 g of the intermediate, 250 g of a cationic monomer, and absolute ethanol uniformly, react at 45 °C for 8 h, and after rotary evaporation, obtain a rosin-based reactive emulsifier. The preparation method of the cationic monomer is as follows: Mix 250 g of epichlorohydrin and 1000 g of toluene uniformly, add 450 g of dimethylaminopropyl acrylamide, react at 65 °C for 3 h, and after rotary evaporation, obtain the cationic monomer. An application of a rosin-based reactive emulsifier includes the following process: Take 1 g of the prepared rosin-based reactive emulsifier, dissolve it in 50 g of deionized water, heat to 70 °C under nitrogen protection, add 30 g of a 1% aqueous solution of ammonium persulfate with stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate, and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7, and obtain an emulsion.

[0021] Example 5: A preparation method of a rosin-based reactive emulsifier includes the following process: Step 1: Disperse 240 g of glycol chitosan in deionized water to obtain a 3 wt% glycol chitosan aqueous solution; add a 12 wt% ethanol aqueous solution of octenyl succinic anhydride to the glycol chitosan aqueous solution, adjust the pH to 8.5 using sodium hydroxide solution, react at 40 °C for 22 h, and after dialysis and freeze-drying, obtain modified glycol chitosan; the amount of the ethanol aqueous solution of octenyl succinic anhydride is 0.18 times the mass of the glycol chitosan aqueous solution. Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 240 g of modified glycol chitosan, and 2.5 g of stannous oxalate, react at 265 °C for 5 h, cool to room temperature, and after rotary evaporation, obtain an intermediate. Step 3: Mix 100 g of the intermediate, 280 g of the cationic monomer, and absolute ethanol uniformly, react at 30 - 50 °C for 6 - 8 h, and after rotary evaporation, obtain a rosin-based reactive emulsifier. The preparation method of the cationic monomer is as follows: Mix 280 g of epichlorohydrin and 1200 g of toluene evenly, add 530 g of dimethylaminopropyl acrylamide, react at 70 °C for 2 h, and obtain the cationic monomer through rotary evaporation; The application of a rosin-based reactive emulsifier includes the following process: Take 1 g of the prepared rosin-based reactive emulsifier, dissolve it in 50 g of deionized water, heat it to 70 °C under nitrogen protection, add 30 g of 1% ammonium persulfate aqueous solution with stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7 to obtain an emulsion.

[0022] Example 6: The preparation method of a rosin-based reactive emulsifier includes the following process: Step 1: Disperse 250 g of glycol chitosan in deionized water to obtain a 3 wt% glycol chitosan aqueous solution; Add a 12 wt% ethanol aqueous solution of octenyl succinic anhydride to the glycol chitosan aqueous solution, adjust the pH = 8.5 with sodium hydroxide solution, react at 40 °C for 24 h, and obtain modified glycol chitosan through dialysis and freeze-drying; The dosage of the ethanol aqueous solution of octenyl succinic anhydride is 0.2 times the mass of the glycol chitosan aqueous solution; Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 250 g of modified glycol chitosan and 3 g of stannous oxalate, react at 270 °C for 4 h, cool to room temperature, and obtain an intermediate through rotary evaporation; Step 3: Mix 100 g of the intermediate, 300 g of the cationic monomer and 1200 g of absolute ethanol evenly, react at 50 °C for 8 h, and obtain the rosin-based reactive emulsifier through rotary evaporation; The preparation method of the cationic monomer is as follows: Mix 300 g of epichlorohydrin and 1500 g of toluene evenly, add 600 g of dimethylaminopropyl acrylamide, react at 70 °C for 4 h, and obtain the cationic monomer through rotary evaporation; The application of a rosin-based reactive emulsifier includes the following process: Take 1 g of the prepared rosin-based reactive emulsifier, dissolve it in 50 g of deionized water, heat it to 70 °C under nitrogen protection, add 30 g of 1% ammonium persulfate aqueous solution with stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7 to obtain an emulsion.

[0023] Comparative Example 1: The preparation method of a rosin-based reactive emulsifier includes the following process: Step 1: Under nitrogen protection, 100 g of maleic rosin, 200 g of glycol chitosan, and 1.8 g of stannous oxalate were mixed and reacted at 255 °C for 6 h. After cooling to room temperature, the mixture was subjected to rotary evaporation to obtain an intermediate; Step 3: 100 g of the intermediate, 200 g of the cationic monomer, and 1100 g of absolute ethanol were mixed evenly and reacted at 40 °C for 7 h. After rotary evaporation, a rosin-based reactive emulsifier was obtained; The preparation method of the cationic monomer is as follows: 200 g of epichlorohydrin and 700 g of toluene were mixed evenly, 360 g of dimethylaminopropylacrylamide was added, and the mixture was reacted at 65 °C for 3 h. After rotary evaporation, the cationic monomer was obtained; Taking Example 3 as a control group, in Comparative Example 1, the modified glycol chitosan was replaced with the same mass of glycol chitosan, and the other steps were the same as those in Example 3.

[0024] Comparative Example 2: A preparation method of a rosin-based reactive emulsifier, including the following process: Step 1: 200 g of glycol chitosan was dispersed in deionized water to obtain a 2 wt% glycol chitosan aqueous solution; an 11 wt% ethanol aqueous solution of octenyl succinic anhydride was added to the glycol chitosan aqueous solution, and the pH was adjusted to 8.4 with a sodium hydroxide solution and reacted at 35 °C for 24 h. After dialysis and freeze-drying, modified glycol chitosan was obtained; the dosage of the ethanol aqueous solution of octenyl succinic anhydride was 0.15 times the mass of the glycol chitosan aqueous solution; Step 2: Under nitrogen protection, 100 g of maleic rosin, 200 g of modified glycol chitosan, and 1.8 g of stannous oxalate were mixed and reacted at 255 °C for 6 h. After cooling to room temperature, the mixture was subjected to rotary evaporation to obtain a rosin-based reactive emulsifier; Taking Example 3 as a control group, in Comparative Example 2, the cationic monomer was not introduced, and the other steps were the same as those in Example 3.

[0025] Comparative Example 3: A preparation method of a rosin-based reactive emulsifier, including the following process: Step 1: 200 g of ethylene glycol was dispersed in deionized water to obtain a 2 wt% ethylene glycol aqueous solution; an 11 wt% ethanol aqueous solution of octenyl succinic anhydride was added to the ethylene glycol aqueous solution, and the pH was adjusted to 8.4 with a sodium hydroxide solution and reacted at 35 °C for 24 h. After dialysis and freeze-drying, modified ethylene glycol was obtained; the dosage of the ethanol aqueous solution of octenyl succinic anhydride was 0.15 times the mass of the ethylene glycol aqueous solution; Step 2: Under nitrogen protection, 100 g of maleic rosin, 200 g of modified glycol chitosan, and 1.8 g of stannous oxalate were mixed and reacted at 255 °C for 6 h. After cooling to room temperature, the mixture was subjected to rotary evaporation to obtain an intermediate; Step 3: Mix 100 g of the intermediate, 200 g of the cationic monomer, and 1100 g of absolute ethanol uniformly, react at 40 °C for 7 h, and obtain the rosin-based reactive emulsifier through rotary evaporation; The preparation method of the cationic monomer is as follows: Mix 200 g of epichlorohydrin and 700 g of toluene uniformly, add 360 g of dimethylaminopropyl acrylamide, react at 65 °C for 3 h, and obtain the cationic monomer through rotary evaporation; Taking Example 3 as the control group, in Comparative Example 3, ethylene glycol chitosan was replaced with the same mass of ethylene glycol, and other steps were the same as those in Example 3.

[0026] Comparative Example 4: A preparation method of a rosin-based reactive emulsifier, including the following process: Step 1: Disperse 200 g of ethylene glycol chitosan in deionized water to obtain a 2 wt% ethylene glycol chitosan aqueous solution; add an 11 wt% aqueous solution of octenyl succinic anhydride in ethanol to the ethylene glycol chitosan aqueous solution, adjust the pH = 8.4 using a sodium hydroxide solution, react at 35 °C for 24 h, and obtain the modified ethylene glycol chitosan through dialysis and freeze-drying; the dosage of the aqueous solution of octenyl succinic anhydride in ethanol is 0.15 times the mass of the ethylene glycol chitosan aqueous solution; Step 2: Under nitrogen protection, mix 100 g of maleic rosin, 200 g of the modified ethylene glycol chitosan, and 1.8 g of stannous oxalate, react at 255 °C for 6 h, cool to room temperature, and obtain the intermediate through rotary evaporation; Step 3: Mix 100 g of the intermediate, 50 g of the cationic monomer, and 1100 g of absolute ethanol uniformly, react at 40 °C for 7 h, and obtain the rosin-based reactive emulsifier through rotary evaporation; Taking Example 3 as the control group, in Step 3 of Comparative Example 4, the mass ratio of the intermediate to the cationic monomer is 1:0.5; other steps are the same as those in Example 2.

[0027] Experiment: Prepare a control group sample using sodium dodecylbenzenesulfonate as the emulsifier. The specific steps are as follows: Take 1 g of sodium dodecylbenzenesulfonate, dissolve it in 50 g of deionized water, heat to 70 °C under nitrogen protection, add 30 g of a 1% aqueous solution of ammonium persulfate with stirring, add a mixture of 2 g of acrylic acid, 15 g of styrene, 18 g of butyl acrylate, and 30 g of methyl methacrylate, heat to 85 °C and react for 3 h, adjust the pH to 7, and obtain it; Take the emulsions prepared in Examples 1-6, Comparative Examples 1-4, and the control group, make them into samples, and detect their properties and record the detection results respectively: 1. Ion stability test: Mix a 5 wt% calcium chloride solution and the emulsion in a volume ratio of 1:5 uniformly, let it stand at room temperature for 48 h, and observe whether it layers or demulsifies to detect its ion stability.

[0028] 2. Water absorption test: The emulsion was scraped on a transparent glass plate to form a latex film (thickness 150 μm), baked in an oven at 50 °C for 30 min, taken out, placed in deionized water, soaked for 24 h, taken out, and the mass before and after soaking was recorded to calculate the water absorption rate.

[0029] 3. Adhesion test: The adhesion of the latex film was tested according to GB / T 1720-2020 "Cross-Cut Test for Films" and rated. It was divided into 7 grades, with grade 1 being the best and grade 7 being the worst.

[0030] The test results are shown in Table 1.

[0031] Table 1 Performance test results of rosin-based reactive emulsifier and sodium dodecylbenzenesulfonate

[0032] From the data in the above table, the following conclusions can be clearly obtained: 1. It can be seen from Examples 1-6 that the rosin-based reactive emulsifier prepared by the present invention has good emulsifying performance and excellent stability. Compared with the control group, the water absorption rate of the prepared latex film decreased significantly. This is because the rosin-based reactive emulsifier has high reactivity, and the double bonds in its molecules participate in free radical polymerization and are in-situ bonded to the surface of latex particles, without migration, effectively preventing the penetration of water, thereby reducing the water absorption rate.

[0033] 2. Compared with Examples 1-6, in Comparative Example 1, ethylene glycol chitosan modified with octenyl succinic anhydride was not used, lacking octenyl long-chain hydrophobic groups, resulting in insufficient hydrophobic anchoring ability of the emulsifier molecules, unable to effectively resist the charge neutralization of Ca 2+ , easy to demulsify, and at the same time the water absorption rate increased significantly and the adhesion decreased; in Comparative Example 2, no cationic monomer was introduced, resulting in a decrease in the stability of the emulsion; in Comparative Example 3, small molecule ethylene glycol was used to replace ethylene glycol chitosan, resulting in the inability to form a chitosan skeleton, unable to carry out subsequent cationic grafting reactions, unable to form stable micelles, poor ionic stability, and the adhesion and water resistance of the latex film deteriorated due to the lack of network structure; in Comparative Example 4, the amount of cations was reduced, the grafting rate of cationic groups was low, and demulsification was easy to occur. It can be seen that the performance of the rosin-based reactive emulsifier prepared by the present invention is affected by its component ratio. By selecting the component ratio within the above range, materials with good emulsifying effects can be prepared.

[0034] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

Claims

1. A preparation method of a rosin-based reactive emulsifier, characterized in that: It includes the following steps: Step 1: Dissolve glycol chitosan in deionized water to obtain an aqueous glycol chitosan solution; add an aqueous solution of octenyl succinic anhydride in ethanol to the aqueous glycol chitosan solution, adjust the pH to 8.3 - 8.5 with sodium hydroxide solution, react at 30 - 40 °C for 22 - 24 h, dialyze and freeze-dry to obtain modified glycol chitosan; Step 2: Under nitrogen protection, mix maleic rosin, modified glycol chitosan and stannous oxalate, react at 240 - 270 °C for 4 - 8 h, cool to room temperature, and perform rotary evaporation to obtain an intermediate; Step 3: Mix the intermediate, cationic monomer and absolute ethanol evenly, react at 30 - 50 °C for 6 - 8 h, and perform rotary evaporation to obtain a rosin-based reactive emulsifier.

2. The preparation method of a rosin-based reactive emulsifier according to claim 1, characterized in that: In Step 1, the concentration of the aqueous glycol chitosan solution is 1 - 3 wt%, and the concentration of the aqueous solution of octenyl succinic anhydride in ethanol is 10 - 12 wt%.

3. The preparation method of a rosin-based reactive emulsifier according to claim 1, characterized in that: In Step 1, the dosage of the aqueous solution of octenyl succinic anhydride in ethanol is 0.1 - 0.2 times the mass of the aqueous glycol chitosan solution.

4. The preparation method of a rosin-based reactive emulsifier according to claim 1, characterized in that: In Step 2, the mass ratio of maleic rosin, modified glycol chitosan and stannous oxalate is 1:(1.5 - 2.5):(0.01 - 0.03).

5. The preparation method of a rosin-based reactive emulsifier according to claim 1, characterized in that: In Step 3, the mass ratio of the intermediate, cationic monomer and absolute ethanol is 1:(1 - 3):(10 - 12).

6. The preparation method of a rosin-based reactive emulsifier according to claim 5, characterized in that: The preparation method of the cationic monomer is as follows: Mix epichlorohydrin and toluene evenly, add dimethylaminopropyl acrylamide, react at 60 - 70 °C for 2 - 4 h, and perform rotary evaporation to obtain the cationic monomer.

7. The preparation method of a rosin-based reactive emulsifier according to claim 6, characterized in that: The mass ratio of epichlorohydrin, dimethylaminopropyl acrylamide and toluene is 1:(1.7 - 2.0):(3 - 5).

8. A rosin-based reactive emulsifier prepared by the preparation method according to any one of claims 1 - 7.

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