A water-based bio-based photo-thermal dual-curing material based on citric acid and epoxy soybean oil and a preparation method thereof

Abstract

This invention discloses a waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil, and its preparation method. The invention involves reacting citric acid with an epoxy compound containing double bonds, followed by the addition of liquid epoxy resin and polyethylene glycol diglycidyl ether, then repeating the reaction with citric acid and the epoxy compound containing double bonds, followed by the addition of liquid epoxy resin and epoxidized soybean oil, then adding an active diluent and deionized water, and finally adding a photoinitiator and a waterborne isocyanate curing agent to obtain the waterborne bio-based photo-thermal dual-curing material. This invention offers advantages such as high bio-based content, renewability, environmental friendliness, and low cost; it eliminates the need for amine neutralization, reducing the residue of unreacted amines in the material; it features a high-functionality photocurable group and a photo-thermal dual-curing system design; and the material properties can be controlled by adjusting the proportions of raw materials, resulting in a synergistic effect that gives the cured material high hardness, high mechanical properties, high water resistance, and high impact resistance.

Description

Technical Field

[0001] This invention relates to the field of waterborne bio-based photo-thermal dual-curing materials technology, specifically to a waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil and its preparation method. Background Technology

[0002] Waterborne bio-based UV-curing coatings are a type of green and environmentally friendly coating. Due to their low volatile organic compound (VOC) emissions, non-toxicity, renewability, and rapid curing, they are widely used in printing, packaging, wooden furniture, and flooring industries.

[0003] UV-curable coatings prepared using soybean oil as a bio-based raw material are a relatively common type of bio-based photocurable material, and have been extensively studied. The main method involves first epoxidizing soybean oil and then reacting it with acrylic acid to prepare soybean oil-based epoxy acrylate resin. In recent years, researchers have been developing new bio-based raw materials to prepare waterborne bio-based photo-thermal dual-curable materials. Citric acid is widely available, low in cost, and non-toxic. Its molecular structure contains three carboxyl groups and one hydroxyl group. After modification, it is a potential new bio-based raw material that can replace acrylic acid in the reaction with epoxidized soybean oil to prepare epoxy acrylate. CN 116217845 A discloses a waterborne bio-based photocurable material and its preparation method. This method successfully prepared a waterborne bio-based epoxy acrylate resin based on citric acid and epoxidized soybean oil. The resulting resin exhibits good hydrophilicity, good storage stability, and good compatibility, making it easy to compound and modify. This results in a photocured coating with high adhesion, high flexibility, high impact resistance, and high gloss. However, this method has the following shortcomings: (1) The performance of waterborne bio-based epoxy acrylate resin based purely on citric acid and epoxidized soybean oil is not good. It improves the material properties by physical blending of waterborne bio-based epoxy acrylate resin based on citric acid and petroleum-based epoxy resin. However, the modification method of physical blending of emulsion cannot make the polymer inside the emulsion particles fully mixed, and its modification effect is limited. At the same time, the bio-based content of waterborne bio-based epoxy acrylate resin based purely on citric acid and epoxidized soybean oil is high, but the bio-based content decreases significantly after blending and modification with waterborne bio-based epoxy acrylate resin based on citric acid and petroleum-based epoxy resin. (2) The prepared waterborne bio-based epoxy acrylate resin is an anionic polymer. It is neutralized with triethylamine to achieve waterborneization. However, the high boiling point of triethylamine makes it easy to remain in the photocurable coating, which leads to a decrease in its performance. At the same time, the use of the neutralizing agent triethylamine increases the VOC emissions of the material system.

[0004] (3) The prepared water-based bio-based photocurable material has low hardness and poor mechanical properties. Summary of the Invention

[0005] In view of the above-mentioned shortcomings, the present invention provides an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil and its preparation method. The aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil of the present invention has the advantages of high bio-based content, renewability, green environmental protection, and low cost. At the same time, it does not require amine neutralization, reducing the residue of unreacted amines. It also features a high-functionality photocurable group and a photo-thermal dual-curing system design. Moreover, the material properties can be controlled by adjusting the proportion of raw materials. The comprehensive synergy results in a photocured coating with high hardness, high mechanical properties, high water resistance, and high impact resistance. It has great application prospects in printing and packaging, wooden furniture, antibacterial and antiviral coatings, medical and health care, children's toys and other fields.

[0006] To achieve the above objectives, this invention provides a method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil, comprising the following steps:

[0007] Step 1: In an inert gas atmosphere, mix citric acid, solvent, catalyst and polymerization inhibitor, slowly heat to 60-90℃, wait for the citric acid to completely dissolve, then slowly add the epoxy compound with double bonds, keep warm for 1 hour after the addition is complete, then heat to 90-110℃ and react for 1-4 hours.

[0008] Preferably, the inert atmosphere is nitrogen.

[0009] Preferably, the above reaction is carried out in an apparatus equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer.

[0010] Step 2: Add polyethylene glycol diglycidyl ether and liquid epoxy resin, and react at 90-110℃ until the acid value no longer changes;

[0011] Step 3: Add citric acid and an epoxy compound with double bonds, and react at 90-110℃ until the acid value no longer changes;

[0012] Step 4: Add liquid epoxy resin and epoxidized soybean oil, and react at 90-110℃ until the acid value no longer changes;

[0013] Step 5: After removing the solvent, cool down to 50-70℃, add the reactive diluent while stirring, then add deionized water while stirring vigorously and maintain for 0.2-1h;

[0014] Preferably, the solvent removal process involves evacuating to a vacuum of ≤-0.09 MPa and maintaining this vacuum for 1 hour to remove the solvent.

[0015] Step 6: Add photoinitiator, leveling agent, and defoamer while stirring, mix evenly, and then add water-based isocyanate curing agent to obtain water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0016] It should be noted that the above-mentioned vigorous stirring is 1000-2000 r / min; stirring is 400-600 r / min.

[0017] According to one aspect of the present invention, in steps 1-5, the mass percentages of each component are as follows:

[0018]

[0019] According to one aspect of the present invention, in step 1, the solvent is one or more of 1,4-dioxane, N,N-dimethylformamide, and dimethyl sulfoxide;

[0020] The catalyst is one of triphenylphosphine, N,N-dimethylaniline, N,N-dimethylbenzylamine, and tetrabutylammonium bromide;

[0021] The polymerization inhibitor is one of hydroquinone, p-benzoquinone, and p-methoxyphenol;

[0022] The epoxy compound with double bonds is one of glycidyl methacrylate and allyl glycidyl ether.

[0023] The liquid epoxy resin is one or more of the following: liquid bisphenol A epoxy resin, hydrogenated liquid bisphenol A epoxy resin, 1,4-cyclohexanediol diglycidyl ether, resorcinol diglycidyl ether, and 1,2-cyclohexanediol diglycidyl ether.

[0024] The polyethylene glycol diglycidyl ether is a polyethylene glycol diglycidyl ether with an epoxy value of 1.0 to 3.5 mmol / g.

[0025] According to one aspect of the invention, in step 1, the molar ratio of citric acid to the double-bonded epoxy compound is 1:1.9 to 2.1.

[0026] According to one aspect of the present invention, in step 2, the molar ratio of epoxy groups of the polyethylene glycol diglycidyl ether to the liquid epoxy resin is 1:0.1 to 1.

[0027] According to one aspect of the invention, in step 3, the molar ratio of the citric acid to the double-bonded epoxy compound is 1:0.9 to 1.1.

[0028] According to one aspect of the present invention, in step 4, the molar ratio of epoxy groups in the liquid epoxy resin and the epoxidized soybean oil is 1:1 to 10.

[0029] According to one aspect of the present invention, the reactive diluent is one or more of diethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol diacrylate, and pentaerythritol triacrylate.

[0030] According to one aspect of the present invention, in step 6, based on the mass of the product prepared in step 5, the mass percentage of the photoinitiator is 2-6%; the mass percentage of the leveling agent is 0.05-0.5%; the mass percentage of the defoamer is 0.1-1%; and the mass percentage of the waterborne isocyanate curing agent is 2-20%.

[0031] The photoinitiator is one or more of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenyl acetone, 2-hydroxy-3-(2'-thioxanthoneoxy)-N,N,N-trimethyl-1-propylamine chloride, 1-hydroxy-cyclohexyl benzophenone, and 2-hydroxy-2-methyl-1-phenyl acetone.

[0032] The leveling agent is an organosilicon surface additive; preferably, the leveling agent is one of organosilicon surface additives BYK-333 and Tego822.

[0033] The defoamer is an organosilicone defoamer; the defoamer is one of organosilicone defoamers BYK-024 and Tego4100.

[0034] Preferably, the aqueous isocyanate curing agent is one or a mixture of several of Covestro's Desmodur N3900 and Bayhydur 401-70MPA / X.

[0035] Based on the same inventive concept, the present invention also provides an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil prepared by the above preparation method.

[0036] The beneficial effects of this invention are:

[0037] The waterborne bio-based photo-thermal dual-curing material of the present invention, based on citric acid and epoxidized soybean oil, has the advantages of high bio-based content, renewability, green environmental protection, and low cost due to the use of citric acid, epoxidized soybean oil, and bio-based polyethylene glycol diglycidyl ether (ethylene glycol bio-based source).

[0038] The present invention relates to a water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil. The main resin is water-based through hydrophilic polyethylene glycol segments, eliminating the need for amine neutralization. This avoids the residual non-reactive organic amines affecting the material performance and reduces VOC emissions from the material system due to the absence of organic amine emissions.

[0039] This invention relates to a waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil. Through molecular structure design and stepwise polymerization process control, raw materials are added in stages, effectively avoiding gelation during the reaction process. Simultaneously, the main resin contains both high-functionality photocurable groups to ensure the system's subsequent photocuring performance, and a large number of hydroxyl groups. These hydroxyl groups can be partially reacted by adding a waterborne isocyanate curing agent, introducing polyurethane segments into the main resin, further increasing the material's crosslinking density and improving various properties such as hardness and tensile strength. The dual-curing system design combines the advantages of photocuring and thermal curing, allowing the prepared material to achieve rapid initial curing and fixation through photocuring, while thermal curing improves material properties such as adhesion, crosslinking density, hardness, and mechanical properties.

[0040] This invention relates to a water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil. By adjusting the proportions of raw materials in various ways, the material's properties can be controlled. Adjusting the ratio of liquid epoxy resin to polyethylene glycol diglycidyl ether reduces the content of hydrophilic polyethylene glycol segments and introduces rigid groups from the liquid epoxy resin into the main resin, achieving a balance between the hydrophilic and oleophilic properties of the main resin and regulating the performance of the cured material. Furthermore, adjusting the ratio of liquid epoxy resin to epoxidized soybean oil introduces more rigid groups from the liquid epoxy resin into the main resin, further enhancing the performance control after curing. Additionally, adjusting the amount of water-based isocyanate curing agent regulates the content of polyurethane segments, further enhancing the performance control after curing. Therefore, this comprehensive synergy results in a photocured coating with excellent properties such as high hardness, high mechanical properties, high water resistance, and high impact resistance, showing great application potential in printing and packaging, wooden furniture, antibacterial and antiviral coatings, medical and health applications, and children's toys.

[0041] The water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil of the present invention introduces raw materials with different structures during the synthesis process to improve the material properties, avoiding the problem that the physical blending of the emulsion in the later stage cannot fully mix the emulsion particles and thus the modification effect is limited. Attached Figure Description

[0042] Figure 1 This is a synthesis route diagram of an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil, as shown in Example 2 of the present invention.

[0043] Figure 2 The infrared spectrum of the main raw materials and the products of the preparation stage of an aqueous bio-based photothermal dual-curing material based on citric acid and epoxidized soybean oil in Example 2 of the present invention is shown. Detailed Implementation

[0044] To make the present invention easier to understand, specific embodiments are described below to further illustrate the invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art; unless otherwise specified, the raw materials and reagents involved herein can be purchased commercially or obtained by known methods.

[0045] It should be noted that the main raw materials for preparing the waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil in this application are denoted as glycidyl methacrylate (GMA), polyethylene glycol diglycidyl ether (EPEGE), liquid bisphenol A epoxy resin (BPAEP), and epoxidized soybean oil (ESO).

[0046] It should be noted that in the preparation methods of waterborne bio-based photo-thermal dual-curing materials based on citric acid and epoxidized soybean oil in the various embodiments of this application, the reaction product of (1) is denoted as C2G, the reaction product of (2) is denoted as ECG, the reaction product of (3) is denoted as AECG, and the reaction product of (4) is denoted as EPCG.

[0047] The following detailed explanation is further illustrated with specific examples.

[0048] Example 1

[0049] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 38.18 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g and 1.59 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes. (4) Add 3.98g of liquid bisphenol A epoxy resin and 4.69g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 120g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 6.60g of Bayhydur401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0050] Example 2

[0051] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil, the synthesis route of which is shown in the figure below. Figure 1As shown: (1) In an apparatus equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, purge with nitrogen, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate (GMA), an epoxy compound with double bonds. After the addition is complete, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h to obtain the reaction product C2G. (2) Add 33.94 g of polyethylene glycol diglycidyl ether (EPEGE) with an epoxy value of 1.65 mmol / g and 3.18 g of liquid bisphenol A epoxy resin (BPAEP), and react at 100°C until the acid value no longer changes to obtain the reaction product ECG. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate (GMA), an epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes to obtain the reaction product AECG. (4) Add 3.98g of liquid bisphenol A epoxy resin (BPAEP) and 4.69g of epoxidized soybean oil (ESO), and react at 100℃ until the acid value no longer changes to obtain the reaction product EPCG. (5) Vacuum the solution to ≤-0.09MPa and maintain it for 1h to remove the solvent. Then cool the solution to 60℃ and add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min). Then add 115g of deionized water while stirring vigorously (1500r / min) and maintain the solution for 0.5h. (6) Under stirring (500 r / min), add 4.00 g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50 g of BYK-333 leveling agent, and 0.50 g of BYK-024 defoamer. After mixing evenly, add 6.60 g of Bayhydur 401-70MPA / X waterborne isocyanate curing agent to obtain a waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil. The infrared spectra of the main raw materials and products in the preparation process are shown below. Figure 2 As shown.

[0052] Example 3

[0053] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 29.70 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g and 4.78 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes. (4) Add 3.98g of liquid bisphenol A epoxy resin and 4.69g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 110g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 6.60g of Bayhydur401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0054] Example 4

[0055] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 33.94 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g and 3.18 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes. (4) Add 3.98g of liquid bisphenol A epoxy resin and 4.69g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 115g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 9.90g of Bayhydur401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0056] Example 5

[0057] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 33.94 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g and 3.18 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes. (4) Add 1.59g of liquid bisphenol A epoxy resin and 7.51g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 115g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 6.60g of Bayhydur401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0058] Comparative Example 1

[0059] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In an apparatus equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is complete, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 42.42 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g, and react at 100°C until the acid value no longer changes. (3) Add 6.72 g of citric acid and 4.98 g of glycidyl methacrylate epoxy compound with double bonds, and react at 100°C until the acid value no longer changes. (4) Add 9.39g of epoxidized soybean oil and react at 100℃ until the acid value no longer changes. (5) Vacuum the material to ≤-0.09MPa and keep it for 1h to remove the solvent. Then cool it down to 60℃ and add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min). Then add 120g of deionized water while stirring vigorously (1500r / min) and keep it for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer while stirring (500r / min). Mix well and then add 6.60g of Bayhydur 401-70MPA / X waterborne isocyanate curing agent to obtain a waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0060] Comparative Example 2

[0061] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In an apparatus equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is complete, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 42.42 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g, and react at 100°C until the acid value no longer changes. (3) Add 6.72 g of citric acid and 4.98 g of glycidyl methacrylate epoxy compound with double bonds, and react at 100°C until the acid value no longer changes. (4) Add 3.98g of liquid bisphenol A epoxy resin and 4.69g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 120g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 6.60g of Bayhydur 401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0062] Comparative Example 3

[0063] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 33.94 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g and 3.18 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate (an epoxy compound with double bonds), and react at 100℃ until the acid value no longer changes. (4) Add 9.39g of epoxidized soybean oil and react at 100℃ until the acid value no longer changes. (5) Vacuum the mixture to ≤-0.09MPa and maintain for 1h to remove the solvent. Then cool the mixture to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 120g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 6.60g of Bayhydur 401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0064] Comparative Example 4

[0065] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 33.94 g of polyethylene glycol diglycidyl ether with an epoxy value of 1.65 mmol / g and 3.18 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes. (4) Add 3.98g of liquid bisphenol A epoxy resin and 4.69g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 115g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min). After mixing evenly, the water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is obtained.

[0066] Comparative Example 5

[0067] A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil is as follows: (1) In a device equipped with a stirrer, a constant pressure funnel, a condenser and a thermometer, add 6.72 g of citric acid, 20.0 g of dioxane solvent, 0.50 g of triphenylphosphine catalyst and 0.50 g of p-methoxyphenol polymerization inhibitor, introduce nitrogen gas, slowly raise the temperature to 80°C, wait for the citric acid to completely dissolve, and then slowly add 9.95 g of glycidyl methacrylate epoxy compound with double bonds. After the addition is completed, keep warm for 1 h, and then raise the temperature to 100°C and react for 2 h. (2) Add 14.93 g of polyethylene glycol diglycidyl ether with an epoxy value of 3.75 mmol / g and 3.18 g of liquid bisphenol A epoxy resin, and react at 100°C until the acid value no longer changes. (3) Add 6.72g of citric acid and 4.98g of glycidyl methacrylate epoxy compound with double bonds, and react at 100℃ until the acid value no longer changes. (4) Add 3.98g of liquid bisphenol A epoxy resin and 4.69g of epoxidized soybean oil, and react at 100℃ until the acid value no longer changes. (5) Vacuum the solution to ≤-0.09MPa, maintain for 1h to remove the solvent, then cool to 60℃, add 2.50g of dipropylene glycol diacrylate reactive diluent while stirring (500r / min), and then add 120g of deionized water while stirring vigorously (1500r / min) and maintain for 0.5h. (6) Add 4.00g of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone photoinitiator, 0.50g of BYK-333 leveling agent, and 0.50g of BYK-024 defoamer under stirring (500r / min), mix evenly, and then add 6.60g of Bayhydur401-70MPA / X waterborne isocyanate curing agent to obtain waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil.

[0068] Performance testing and results analysis:

[0069] The aqueous bio-based photothermal dual-curing materials based on citric acid and epoxidized soybean oil prepared in Examples 1-5 and Comparative Examples 1-5 were coated onto a 150-micron wire rod, dried at room temperature for 2 hours, and then dried in a 40°C drying oven for 2 hours. Finally, the wet film was irradiated with a 4kW high-pressure mercury lamp at a distance of 10cm for 20s, and then heated in an 80°C oven for 3 hours to obtain the cured coating.

[0070] Appearance was determined visually; storage stability was assessed by visually observing changes in appearance after centrifugation at 3000 rpm for 15 minutes; adhesion was tested using an adhesion tester with the cross-cut test method according to GB / T4893.4-2013 "Tests for Physical and Chemical Properties of Furniture Surface Coatings Part 4: Adhesion Cross-Cut Method"; pencil hardness was tested using the pencil hardness method according to GB / T 6739-2006 "Determination of Hardness of Coatings by Pencil Method"; flexibility was tested according to GB / T The coating was tested according to GB / T 1731-1993 "Test Method for Flexibility of Coating Film"; impact resistance was tested according to GB / T 1732-1993 "Test Method for Impact Resistance of Coating Film"; water resistance was tested by first drying the coating film in a 60℃ oven for 24 hours and weighing it W0, then immersing it in deionized water at 20℃ for 24 hours and weighing it W1, and finally calculating the water resistance S = (W1-W0)*100% / W0; tensile strength and elongation at break were tested using a universal testing machine at a tensile rate of 10 mm / min; bio-based content was calculated according to the USDA's definition of bio-based content as "the percentage of biocarbon in a material or product by weight (mass) of the total organic carbon in the product". The test results for each performance are shown in Table 1.

[0071] Table 1. Performance test results of different waterborne bio-based photo-thermal dual-curing materials based on citric acid and epoxidized soybean oil.

[0072]

[0073] As shown in Tables 1-5, the various waterborne bio-based photo-thermal dual-curing materials based on citric acid and epoxidized soybean oil prepared by the method of the present invention exhibit good storage stability, flexibility, impact resistance, mechanical properties, water resistance, high bio-based content, good adhesion, and high hardness. They have great application prospects in the field of waterborne bio-based photocuring materials, particularly in printing and packaging, wooden furniture, antibacterial and antiviral coatings, medical and health applications, and children's toys. A comparative analysis of Examples 1-5 and Comparative Example 1 in Tables 1 shows that the waterborne bio-based photo-thermal dual-curing materials based on citric acid and epoxidized soybean oil prepared without the introduction of liquid bisphenol A epoxy resin in steps (2) and (4) of the preparation method exhibit poor water resistance and mechanical properties. Comparative analysis of Examples 1-5, Comparative Examples 1 and 2 in Table 1 shows that the water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil prepared without the introduction of liquid bisphenol A epoxy resin in step (2) of the preparation method has poor water resistance and mechanical properties, but is better than Comparative Example 1. Comparative analysis of Examples 1-5, Comparative Examples 1-2 and Comparative Example 3 in Table 1 shows that the water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil prepared without the introduction of liquid bisphenol A epoxy resin in step (4) of the preparation method has poor mechanical properties, but its water resistance is better than Comparative Examples 1 and 2. Therefore, it is proven that the introduction of liquid bisphenol A epoxy resin in step (2) of the preparation method is a necessary condition for improving the water resistance of the material, and the introduction of liquid bisphenol A epoxy resin in step (4) of the preparation method can improve the overall water resistance and mechanical properties of the material. Comparative analysis of Examples 3 and 4 and Comparative Example 4 in Table 1 shows that the waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil prepared without the introduction of waterborne isocyanate curing agent in step (6) of the preparation method has low hardness, poor water resistance, and poor mechanical properties. Therefore, it is proven that the introduction of waterborne isocyanate curing agent is very important for improving material performance and is also an essential raw material for the design of photo-thermal dual-curing material system. Comparative analysis of Examples 2 and Comparative Example 5 in Table 1 shows that the waterborne bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil prepared using polyethylene glycol diglycidyl ether with an epoxy value of 3.75 mmol / g in step (2) of the preparation method has poor storage stability, poor impact resistance, low elongation at break, and low bio-based content. Therefore, it is proven that the optimal selection of polyethylene glycol diglycidyl ether with different epoxy values ​​is crucial for material performance.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing an aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil, characterized in that, Includes the following steps: Step 1: In an inert gas atmosphere, mix citric acid, solvent, catalyst and polymerization inhibitor, slowly heat to 60~90℃, wait for the citric acid to completely dissolve, then slowly add the epoxy compound with double bonds, keep warm for 1 hour after the addition is complete, then heat to 90~110℃ and react for 1~4 hours. Step 2: Add polyethylene glycol diglycidyl ether and liquid epoxy resin, and react at 90~110℃ until the acid value no longer changes; Step 3: Add citric acid and an epoxy compound with double bonds, and react at 90~110℃ until the acid value no longer changes; Step 4: Add liquid epoxy resin and epoxidized soybean oil, and react at 90~110℃ until the acid value no longer changes; Step 5: After removing the solvent, cool down to 50~70℃, add the active diluent while stirring, then add deionized water while stirring vigorously and maintain for 0.2~1h; Step 6: Add photoinitiator, leveling agent, and defoamer while stirring, mix evenly, and then add water-based isocyanate curing agent to obtain water-based bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil. In steps 1-5, the mass percentage of each component is as follows: Citric acid 5-12%; Solvent 10-20%; Catalyst 0.2-0.5%; Polymerization inhibitor 0.2-0.5%; Epoxides with double bonds: 5-15%; 10-2% polyethylene glycol diglycidyl ether; Liquid epoxy resin 1-8%; Epoxidized soybean oil 2-8%; Reactive diluent 0-5%; Deionized water 40-70%; In step S1, the solvent is one or more of 1,4-dioxane, N,N-dimethylformamide, and dimethyl sulfoxide; the catalyst is one of triphenylphosphine, N,N-dimethylaniline, N,N-dimethylbenzylamine, and tetrabutylammonium bromide; and the polymerization inhibitor is one of hydroquinone, p-benzoquinone, and p-methoxyphenol. The epoxy compound with double bonds is one of glycidyl methacrylate and allyl glycidyl ether. The liquid epoxy resin is one or more of the following: liquid bisphenol A epoxy resin, hydrogenated liquid bisphenol A epoxy resin, 1,4-cyclohexanediol diglycidyl ether, resorcinol diglycidyl ether, and 1,2-cyclohexanediol diglycidyl ether. The polyethylene glycol diglycidyl ether is a polyethylene glycol diglycidyl ether with an epoxy value of 1.0~3.5 mmol / g.

2. The preparation method of the aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil according to claim 1, characterized in that, In step 1, the molar ratio of citric acid to the double-bonded epoxy compound is 1:1.9~2.

1.

3. The preparation method of the aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil according to claim 1, characterized in that, In step 2, the molar ratio of epoxy groups in the polyethylene glycol diglycidyl ether to the liquid epoxy resin is 1:0.1~1.

4. The preparation method of the aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil according to claim 1, characterized in that, In step 3, the molar ratio of citric acid to the double-bonded epoxy compound is 1:0.9~1.

1.

5. The preparation method of the aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil according to claim 1, characterized in that, In step 4, the molar ratio of epoxy groups in the liquid epoxy resin and the epoxy soybean oil is 1:1 to 10.

6. The preparation method of the aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil according to claim 1, characterized in that, The reactive diluent is one or more of diethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol diacrylate, and pentaerythritol triacrylate.

7. The preparation method of the aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil according to claim 1, characterized in that, In step 6, based on the mass of the product prepared in step 5, the mass percentage of the photoinitiator is 2-6%; the mass percentage of the leveling agent is 0.05-0.5%; the mass percentage of the defoamer is 0.1-1%; and the mass percentage of the water-based isocyanate curing agent is 2-20%. The photoinitiator is one or more of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenyl acetone, 2-hydroxy-3-(2'-thioxanthoneoxy)-N,N,N-trimethyl-1-propylamine chloride, 1-hydroxy-cyclohexyl benzophenone, and 2-hydroxy-2-methyl-1-phenyl acetone. The leveling agent is an organosilicon surface additive; The defoamer is an organosilicone defoamer.

8. The aqueous bio-based photo-thermal dual-curing material based on citric acid and epoxidized soybean oil prepared by any of the preparation methods described in claims 1-7.

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