An organic-inorganic hybrid modified water-based bio-based photocuring material and a preparation method thereof

Abstract

The application discloses a kind of based on organic-inorganic hybrid modification water-based biological base photocuring material and preparation method thereof, using isocyanatoethyl methacrylate and nano silicon dioxide reaction, modified nano silicon dioxide is prepared, then using citric acid, 3,4-epoxy cyclohexyl methyl methacrylate, epoxy soybean oil, maleic anhydride successfully prepared water-based biological base photocuring resin, finally modified nano silicon dioxide and water-based biological base photocuring resin composite preparation water-based biological base photocuring material.The modified nano silicon dioxide of the application is easily wetted and dispersed by main resin and has good compatibility, can also participate in the photocuring reaction of coating, and form chemical crosslinking with the main resin;And modified nano silicon dioxide and 3,4-epoxy cyclohexyl methyl methacrylate with rigid six-membered ring structure have synergistic effect, and the cured material has high biological base content, high mechanical property, high heat resistance, high pencil hardness and other characteristics.

Description

Technical Field

[0001] This invention relates to the field of waterborne bio-based photocurable materials technology, specifically to a waterborne bio-based photocurable material based on organic-inorganic hybrid modification and its preparation method. Background Technology

[0002] Waterborne bio-based photocurable materials have been widely used in many industries such as furniture, construction, automobiles, electronics, and packaging due to their significant advantages in being green and environmentally friendly. They have become a key material for the coatings industry to reduce volatile organic compound emissions and improve green sustainability.

[0003] Soybean oil, with its abundant production, has been widely used in the field of waterborne bio-based photocurable coatings. However, due to the large amount of long-chain aliphatic hydrocarbons in its molecular structure, soybean oil-based waterborne bio-based photocurable coatings exhibit poor mechanical properties, heat resistance, and hardness, limiting their application in high-performance and high-value-added fields. Therefore, researchers have conducted in-depth studies on how to improve the performance of soybean oil-based waterborne bio-based photocurable coatings and explored various modification schemes to meet the higher performance requirements of different application scenarios, thereby expanding the application areas of soybean oil-based waterborne bio-based photocurable coatings. CN116217845A discloses a waterborne bio-based photocurable material and its preparation method. This method uses liquid bisphenol A epoxy resin and hydrogenated liquid bisphenol A epoxy resin as raw materials to improve the mechanical properties, heat resistance, and adhesion of soybean oil-based waterborne bio-based photocurable coatings. However, this scheme uses petroleum-based epoxy resin modification, which not only significantly reduces the bio-based content but also has limited performance improvement. CN118006220A discloses a waterborne bio-based photocurable material based on photo-thermal dual curing and its preparation method. This method uses a dual curing process to improve the mechanical properties, heat resistance, and pencil hardness of soybean oil-based waterborne bio-based photocurable coatings. However, this scheme uses a post-addition of a waterborne isocyanate curing agent, making it a two-component material. This is more complex to prepare on-site than single-component materials, and the dual curing process—first photocuring and then thermal curing—is complex, increasing energy consumption compared to a simple photocuring process, thus losing the green and energy-saving characteristics of photocuring. Summary of the Invention

[0004] In view of the above-mentioned shortcomings, this invention provides an aqueous bio-based photocurable material based on organic-inorganic hybrid modification and its preparation method. This invention uses isocyanate methacrylate to modify nano-silica. The modified nano-silica is easily wetted and dispersed by the host resin, exhibiting good compatibility. It can also participate in the photocuring reaction of coatings, forming chemical crosslinks with the host resin. The modified nano-silica synergistically interacts with 3,4-epoxycyclohexylmethyl methacrylate, which has a rigid six-membered ring structure, resulting in a cured material with high bio-based content, high mechanical properties, high heat resistance, and high pencil hardness. It has great application prospects in food packaging, pharmaceuticals, children's toys, automotive interiors, and high-end printing.

[0005] To achieve the above objectives, this invention provides a method for preparing an aqueous bio-based photocurable material based on organic-inorganic hybrid modification, comprising the following steps:

[0006] Step 1: Dissolve and disperse nano-silica in acetone to obtain a nano-silica dispersion;

[0007] Step 2: Under an inert atmosphere, the polymerization inhibitor and the nano silica dispersion are mixed, and then the modified functional monomer with monoisocyanate group and double bond is added. The mixture is heated to 50-70℃ and reacted for 2 hours. Then, dibutyltin dilaurate is added and the mixture is reacted at 50-70℃ for another 12 hours to obtain modified nano silica.

[0008] Step 3: Under an inert atmosphere, citric acid, polymerization inhibitor, catalyst, and 1,4-dioxane are mixed, heated to 80-95℃ and kept at this temperature until the citric acid is completely dissolved. Then, methacrylate with an alicyclic structure is added dropwise and reacted for 0.5 hours. The temperature is then raised to 95-105℃ and the reaction continues until the acid value no longer changes. Epoxidized soybean oil is then added, and the reaction continues at 95-110℃ for 1 hour. The temperature is then controlled at 110℃ and the reaction continues until the acid value no longer changes. The reaction system temperature is then lowered to 80℃, and maleic anhydride is added, and the reaction continues until the acid value no longer changes.

[0009] Step 4: Add modified nano-silica, stir until fully mixed, remove solvent by vacuum, then lower the temperature to 50-70℃, slowly add triethylamine, add deionized water under vigorous stirring and maintain for 0.5h, then filter to obtain the product;

[0010] Step 5: Add photoinitiator, leveling agent and defoamer to the product while stirring, and mix evenly to obtain a water-based bio-based photocurable material based on organic-inorganic hybrid modification.

[0011] According to one aspect of the present invention, in steps 1-2, the mass percentages of each component are as follows:

[0012]

[0013] According to one aspect of the present invention, in step 1, the nano-silica is a hydrophilic fumed silica, such as one of Deshan Chemical QS102, Cabot M-5, Evonik A200, and Wacker Chemie N20. Its dissolution and dispersion process can be carried out by first stirring to dissolve and then stirring vigorously to disperse. For example, stirring at 500-800 rpm until the nano-silica is basically dissolved, and then stirring vigorously at 5000-6000 rpm until it is evenly dispersed.

[0014] According to one aspect of the present invention, in step 2, the modified functional monomer with monoisocyanate group and double bond is ethyl isocyanate methacrylate.

[0015] According to one aspect of the invention, in step 2, the polymerization inhibitor is one or a mixture of several of hydroquinone, p-benzoquinone, p-tert-butylcatechol, and p-methoxyphenol.

[0016] According to one aspect of the present invention, in steps 3-4, the mass percentages of each component are as follows:

[0017]

[0018] According to one aspect of the present invention, in step 3, the methacrylate with an alicyclic structure is 3,4-epoxycyclohexylmethyl methacrylate.

[0019] According to one aspect of the present invention, in step 3, the polymerization inhibitor is one or a mixture of several of hydroquinone, p-benzoquinone, p-tert-butylcatechol, and p-methoxyphenol;

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

[0021] According to one aspect of the present invention, in step 5, based on the mass of the product prepared in step 4, the mass percentage of the photoinitiator is 2-5%; the mass percentage of the leveling agent is 0.05-0.5%; and the mass percentage of the defoamer is 0.1-1%.

[0022] According to one aspect of the present invention, in step 5, the photoinitiator is one or more of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenyl acetone, 1-hydroxy-cyclohexyl benzophenone, and 2-hydroxy-2-methyl-1-phenyl acetone;

[0023] The leveling agent is an organosilicon surface additive, such as BYK-333 or Tego822;

[0024] The defoamer is an organosilicon defoamer, such as BYK-024 or Tego4100.

[0025] Based on the same inventive concept, the present invention also provides an aqueous bio-based photocurable material prepared by the above preparation method based on organic-inorganic hybrid modification.

[0026] The beneficial effects of this invention are:

[0027] This invention relates to an organic-inorganic hybrid modified waterborne bio-based photocurable material, which uses isocyanate methacrylate as the modified functional monomer and has multiple advantages. First, isocyanate methacrylate is a monofunctional isocyanate that can react with the surface hydroxyl groups of nano-silica, resulting in a controllable product structure and a relatively simple synthesis process. Second, the organic segments of isocyanate methacrylate can improve the wetting and dispersibility of the nano-silica surface, allowing it to be uniformly dispersed in the polymer resin with good compatibility. Finally, the carbon-carbon double bonds in the isocyanate methacrylate structure can participate in the crosslinking of the host resin during photocuring, forming a three-dimensional chemical crosslinked structure with the host resin.

[0028] This invention relates to an aqueous bio-based photocurable material based on organic-inorganic hybrid modification. It utilizes photocurable, dispersible, and compatible modified nano-silica. The organic-inorganic hybrid modification enhances the mechanical properties, heat resistance, and pencil hardness of the photocurable material. It also features low dosage, minimal reduction in bio-based content, and excellent enhancement and modification effects.

[0029] The waterborne bio-based photocurable material of the present invention, based on organic-inorganic hybrid modification, uses 3,4-epoxycyclohexylmethyl methacrylate with a rigid six-membered ring structure, which can significantly improve the rigidity of polymer molecules and further improve the mechanical properties, heat resistance, pencil hardness and other properties of the photocurable material.

[0030] The waterborne bio-based photocurable material based on organic-inorganic hybrid modification of the present invention significantly improves the mechanical properties, elastic modulus, heat resistance, pencil hardness and other properties of the photocurable material due to the synergistic effect of modified nano-silica with good photocurability, dispersibility and compatibility and 3,4-epoxycyclohexylmethyl methacrylate with rigid six-membered ring structure.

[0031] The waterborne bio-based photocurable material of the present invention, based on organic-inorganic hybrid modification, has the characteristics of high bio-based content, renewability, and green environmental protection due to the use of bio-based raw materials such as citric acid, epoxidized soybean oil, and maleic anhydride.

[0032] The waterborne bio-based photocurable material based on organic-inorganic hybrid modification of the present invention is a single-component photocurable material that does not require thermal curing, has a simple curing process, and is green and energy-saving.

[0033] The waterborne bio-based photocurable material based on organic-inorganic hybrid modification of the present invention has the characteristics of high bio-based content, high mechanical properties, high heat resistance, and high pencil hardness, and has great application prospects in food packaging, medicine and health, children's toys, automotive interiors, high-end printing and other fields. Attached Figure Description

[0034] Figure 1 This is a synthesis route diagram for step 2 of a method for preparing an aqueous bio-based photocurable material based on organic-inorganic hybrid modification in Embodiment 2 of the present invention;

[0035] Figure 2 This is a synthetic route diagram of step 3 in a method for preparing an aqueous bio-based photocurable material based on organic-inorganic hybrid modification according to Embodiment 2 of the present invention;

[0036] Figure 3 The infrared spectra of the main raw materials and modified nano-silica in step 2 of the preparation method of an organic-inorganic hybrid modified waterborne bio-based photocurable material according to Embodiment 2 of the present invention are shown.

[0037] Figure 4 The infrared spectra of the main raw materials and stage products in step 3 of the preparation method of waterborne bio-based photocurable material based on organic-inorganic hybrid modification in Embodiment 2 of the present invention are shown. Detailed Implementation

[0038] 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.

[0039] It should be noted that in the preparation method of waterborne bio-based photocurable material based on organic-inorganic hybrid modification in various embodiments of this application, the first reaction product of step 3 (the reaction product of citric acid and methacrylate with alicyclic structure) is denoted as EC2, the second reaction product (the reaction product of EC2 and epoxidized soybean oil) is denoted as ECE, and the third reaction product (the reaction product of ECE and maleic anhydride) is denoted as ECEM.

[0040] The following detailed explanation is further illustrated with specific examples.

[0041] Example 1

[0042] (1) Add 20.00g of nano silica (Tokuyama QS102 from Japan) to 200.00g of acetone. First, stir at 600rpm until the nano silica is basically dissolved, then disperse at 6000rpm for 18min to obtain a nano silica dispersion.

[0043] (2) In a 100mL three-necked flask equipped with a stirrer and a reflux condenser, add 0.05g of p-methoxyphenol and 39.00g of nano silica dispersion, then purge with nitrogen gas, and then add 2.05g of modified functional monomer isocyanate methyl methacrylate with monoisocyanate group and double bond. Heat to 60℃ and react for 2h, then add 0.05g of dibutyltin dilaurate, and continue to react at 60℃ for 12h before stopping the reaction to obtain modified nano silica, which is stored in the dark for later use.

[0044] (3) Add 11.53g of citric acid, 0.39g of polymerization inhibitor p-methoxyphenol, 0.70g of catalyst triphenylphosphine, and 17.29g of 1,4-dioxane to a 250mL three-necked flask. Attach a stirrer and reflux condenser, purge with nitrogen, and heat to 90℃. Maintain this temperature until the citric acid is completely dissolved. Then add 24.28g of 3,4-epoxycyclohexylmethyl methacrylate with an alicyclic structure dropwise over approximately 0.5 hours, and continue the reaction for another 0.5 hours. Then heat to 100℃ and continue the reaction until the acid value of the reaction system no longer changes, at which point the reaction is stopped. Next, add 116.10g of epoxidized soybean oil, and continue the reaction at 100℃ for 1 hour. Finally, heat to 110℃ and continue the reaction until the acid value of the reaction system no longer changes, at which point the reaction is stopped. The reaction system temperature was lowered to 80℃, and then 7.65g of maleic anhydride was added sequentially. The reaction was stopped when the acid value of the system no longer changed.

[0045] (4) Add 1.65g of modified nano-silica and continue stirring for 30min until homogeneous. Then evacuate to ≤-0.095MPa and disperse for about 1h to remove the solvent. Then cool the reaction system to 60℃, slowly add 8.44g of triethylamine, start high-speed stirring, then slowly add 101.70g of deionized water and continue high-speed dispersion for 30min. After filtration, the product is obtained.

[0046] (5) Take 20.00g of the product from step (4) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenyl acetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the water-based bio-based photocurable material modified by organic-inorganic hybridization is obtained.

[0047] Example 2

[0048] (1) Add 20.00g of nano silica (Tokuyama QS102 from Japan) to 200.00g of acetone. First, stir at 600rpm until the nano silica is basically dissolved, then disperse at 6000rpm for 18min to obtain a nano silica dispersion.

[0049] (2) In a 100mL three-necked flask equipped with a stirrer and a reflux condenser, add 0.05g of p-methoxyphenol and 39.00g of nano-silica dispersion, then purge with nitrogen gas, followed by the addition of 2.05g of the modified functional monomer isocyanate methacrylate with monoisocyanate groups and double bonds. The mixture is heated to 60℃ and reacted for 2 hours. Then, 0.05g of dibutyltin dilaurate is added, and the reaction is continued at 60℃ for another 12 hours before the reaction is stopped, yielding modified nano-silica, which is stored in the dark for later use. The synthetic route diagram for its preparation process is shown below. Figure 1 As shown, the infrared spectra of the main raw materials and modified nano-silica are as follows: Figure 3 As shown.

[0050] (3) Add 11.53g of citric acid, 0.39g of polymerization inhibitor p-methoxyphenol, 0.70g of catalyst triphenylphosphine, and 17.29g of 1,4-dioxane to a 250mL three-necked flask. Attach a stirrer and reflux condenser, purge with nitrogen, and heat to 90℃. Maintain this temperature until the citric acid is completely dissolved. Then add 24.28g of 3,4-epoxycyclohexylmethyl methacrylate with an alicyclic structure dropwise over approximately 0.5 hours, and continue the reaction for another 0.5 hours. Then heat to 100℃ and continue the reaction until the acid value of the reaction system no longer changes, at which point the reaction is stopped. Next, add 116.10g of epoxidized soybean oil, and continue the reaction at 100℃ for 1 hour. Finally, heat to 110℃ and continue the reaction until the acid value of the reaction system no longer changes, at which point the reaction is stopped. The reaction system temperature was lowered to 80℃, and then 7.65g of maleic anhydride was added sequentially. The reaction was stopped when the acid value of the system no longer changed. The synthetic route for its preparation process is shown below. Figure 2 As shown, the infrared spectra of the main raw materials and stage products are as follows: Figure 4 As shown.

[0051] (4) Add 3.30g of modified nano-silica and continue stirring for 30min until homogeneous. Then evacuate to ≤-0.095MPa and disperse for about 1h to remove the solvent. Then cool the reaction system to 60℃, slowly add 8.44g of triethylamine, start high-speed stirring, then slowly add 103.00g of deionized water, and continue high-speed dispersion for 30min. After filtration, the product is obtained.

[0052] (5) Take 20.00g of the product from step (4) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenyl acetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the water-based bio-based photocurable material modified by organic-inorganic hybridization is obtained.

[0053] Example 3

[0054] (1) Add 20.00g of nano silica (Tokuyama QS102 from Japan) to 200.00g of acetone. First, stir at 600rpm until the nano silica is basically dissolved, then disperse at 6000rpm for 18min to obtain a nano silica dispersion.

[0055] (2) In a 100mL three-necked flask equipped with a stirrer and a reflux condenser, add 0.05g of p-methoxyphenol and 39.00g of nano silica dispersion, then purge with nitrogen gas, and then add 2.05g of modified functional monomer isocyanate methyl methacrylate with monoisocyanate group and double bond. Heat to 60℃ and react for 2h, then add 0.05g of dibutyltin dilaurate, and continue to react at 60℃ for 12h before stopping the reaction to obtain modified nano silica, which is stored in the dark for later use.

[0056] (3) Add 11.53g of citric acid, 0.39g of polymerization inhibitor p-methoxyphenol, 0.70g of catalyst triphenylphosphine, and 17.29g of 1,4-dioxane to a 250mL three-necked flask. Attach a stirrer and reflux condenser, purge with nitrogen, and heat to 90℃. Maintain this temperature until the citric acid is completely dissolved. Then add 24.28g of 3,4-epoxycyclohexylmethyl methacrylate with an alicyclic structure dropwise over approximately 0.5 hours, and continue the reaction for another 0.5 hours. Then heat to 100℃ and continue the reaction until the acid value of the reaction system no longer changes, at which point the reaction is stopped. Next, add 116.10g of epoxidized soybean oil, and continue the reaction at 100℃ for 1 hour. Finally, heat to 110℃ and continue the reaction until the acid value of the reaction system no longer changes, at which point the reaction is stopped. The reaction system temperature was lowered to 80℃, and then 7.65g of maleic anhydride was added sequentially. The reaction was stopped when the acid value of the system no longer changed.

[0057] (4) Add 4.95g of modified nano-silica and continue stirring for 30min until homogeneous. Then evacuate to ≤-0.095MPa and disperse for about 1h to remove the solvent. Then cool the reaction system to 60℃, slowly add 8.44g of triethylamine, start high-speed stirring, then slowly add 104.40g of deionized water, and continue high-speed dispersion for 30min. After filtration, the product is obtained.

[0058] (5) Take 20.00g of the product from step (4) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the waterborne bio-based photocurable material based on organic-inorganic hybrid modification is obtained.

[0059] Comparative Example 1

[0060] (1) 11.53 g of citric acid, 0.39 g of polymerization inhibitor p-methoxyphenol, 0.70 g of catalyst triphenylphosphine, and 17.29 g of 1,4-dioxane were added sequentially to a 250 mL three-necked flask. A stirring device and a reflux condenser were installed, nitrogen gas was introduced, and the temperature was raised to 90 °C and maintained until the citric acid was completely dissolved. Then, 24.28 g of 3,4-epoxycyclohexylmethyl methacrylate with an alicyclic structure was added dropwise over approximately 0.5 h, and the reaction continued for another 0.5 h. The temperature was then raised to 100 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. Next, 116.10 g of epoxidized soybean oil was added sequentially, and the reaction continued at 100 °C for 1 h. The temperature was then raised to 110 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. The reaction system temperature was lowered to 80℃, and then 7.65g of maleic anhydride was added sequentially. The reaction was stopped when the acid value of the system no longer changed.

[0061] (2) Vacuum the system to ≤-0.095MPa and let it run for about 1 hour to remove the solvent. Then, cool the reaction system to 60°C and slowly add 8.44g of triethylamine. Start high-speed stirring and slowly add 100.30g of deionized water. Continue high-speed dispersion for 30 minutes and then filter to obtain the product.

[0062] (3) Take 20.00g of the product from step (2) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the water-based bio-based photocurable material is obtained.

[0063] Comparative Example 2

[0064] (1) Add 20.00g of nano silica (Tokuyama QS102 from Japan) to 200.00g of acetone. First, stir at 600rpm until the nano silica is basically dissolved, then disperse at 6000rpm for 18min to obtain a nano silica dispersion.

[0065] (2) 11.53 g of citric acid, 0.39 g of polymerization inhibitor p-methoxyphenol, 0.70 g of catalyst triphenylphosphine, and 17.29 g of 1,4-dioxane were added sequentially to a 250 mL three-necked flask. A stirring device and a reflux condenser were installed, nitrogen gas was introduced, and the temperature was raised to 90 °C and maintained until the citric acid was completely dissolved. Then, 24.28 g of 3,4-epoxycyclohexylmethyl methacrylate with an alicyclic structure was added dropwise over approximately 0.5 h, and the reaction continued for another 0.5 h. The temperature was then raised to 100 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. Next, 116.10 g of epoxidized soybean oil was added sequentially, and the reaction continued at 100 °C for 1 h. The temperature was then raised to 110 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. The reaction system temperature was lowered to 80℃, and then 7.65g of maleic anhydride was added sequentially. The reaction was stopped when the acid value of the system no longer changed.

[0066] (3) Add 5.91g of nano-silica dispersion and continue stirring for 30min until homogeneous. Then evacuate to ≤-0.095MPa and disperse for about 1h to remove the solvent. Then cool the reaction system to 60℃, slowly add 8.44g of triethylamine, start high-speed stirring, then slowly add 103.00g of deionized water and continue high-speed dispersion for 30min. After filtration, the product is obtained.

[0067] (4) Take 20.00g of the product from step (3) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the water-based bio-based photocurable material is obtained.

[0068] Comparative Example 3

[0069] (1) Add 20.00g of nano silica (Tokuyama QS102 from Japan) to 200.00g of acetone. First, stir at 600rpm until the nano silica is basically dissolved, then disperse at 6000rpm for 18min to obtain a nano silica dispersion.

[0070] (2) In a 100mL three-necked flask equipped with a stirrer and a reflux condenser, add 0.05g of p-methoxyphenol and 39.00g of nano silica dispersion, then purge with nitrogen gas, and then add 2.05g of modified functional monomer isocyanate methyl methacrylate with monoisocyanate group and double bond. Heat to 60℃ and react for 2h, then add 0.05g of dibutyltin dilaurate, and continue to react at 60℃ for 12h before stopping the reaction to obtain modified nano silica, which is stored in the dark for later use.

[0071] (3) 11.53 g citric acid, 0.39 g polymerization inhibitor p-methoxyphenol, 0.70 g catalyst triphenylphosphine, and 17.29 g 1,4-dioxane were added sequentially to a 250 mL three-necked flask. A stirring device and reflux condenser were installed, nitrogen gas was introduced, and the temperature was raised to 90 °C and maintained until the citric acid was completely dissolved. Then, 17.06 g of glycidyl methacrylate without an alicyclic structure was added dropwise over approximately 0.5 h, and the reaction continued for another 0.5 h. The temperature was then raised to 100 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. Next, 116.10 g of epoxidized soybean oil was added sequentially, and the reaction continued at 100 °C for 1 h. The temperature was then raised to 110 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. The temperature of the reaction system was lowered to 80 °C, and then 7.65 g of maleic anhydride was added sequentially, and the reaction continued until the acid value of the system no longer changed, at which point the reaction was stopped.

[0072] (4) Add 3.30g of modified nano-silica and continue stirring for 30min until homogeneous. Then evacuate to ≤-0.095MPa and disperse for about 1h to remove the solvent. Then cool the reaction system to 60℃, slowly add 8.44g of triethylamine, start high-speed stirring, then slowly add 103.00g of deionized water, and continue high-speed dispersion for 30min. After filtration, the product is obtained.

[0073] (5) Take 20.00g of the product from step (4) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the water-based bio-based photocurable material is obtained.

[0074] Comparative Example 4

[0075] (1) 11.53 g citric acid, 0.39 g polymerization inhibitor p-methoxyphenol, 0.70 g catalyst triphenylphosphine, and 17.29 g 1,4-dioxane were added sequentially to a 250 mL three-necked flask. A stirring device and reflux condenser were installed, nitrogen gas was introduced, and the temperature was raised to 90 °C and maintained until the citric acid was completely dissolved. Then, 17.06 g of glycidyl methacrylate without an alicyclic structure was added dropwise over approximately 0.5 h, and the reaction continued for another 0.5 h. The temperature was then raised to 100 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. Next, 116.10 g of epoxidized soybean oil was added sequentially, and the reaction continued at 100 °C for 1 h. The temperature was then raised to 110 °C, and the reaction continued until the acid value of the reaction system no longer changed, at which point the reaction was stopped. The temperature of the reaction system was lowered to 80 °C, and then 7.65 g of maleic anhydride was added sequentially, and the reaction continued until the acid value of the system no longer changed, at which point the reaction was stopped.

[0076] (2) Vacuum the system to ≤-0.095MPa and let it run for about 1 hour to remove the solvent. Then, cool the reaction system to 60°C and slowly add 8.44g of triethylamine. Start high-speed stirring and slowly add 103.00g of deionized water. Continue high-speed dispersion for 30 minutes and then filter to obtain the product.

[0077] (3) Take 20.00g of the product from step (2) and add 0.50g of initiator 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenylacetone, 0.04g of leveling agent BYK-333 and 0.10g of defoamer BYK-024 under stirring. After mixing evenly, the water-based bio-based photocurable material is obtained.

[0078] Performance testing and results analysis:

[0079] The aqueous bio-based photocurable materials prepared in Examples 1-3 and Comparative Examples 1-4 were coated onto a 150-micron wire rod, left to dry at room temperature for 24 hours, and then dried in a 40°C drying oven for 5 hours. Finally, the wet film was irradiated with a 4kW high-pressure mercury lamp at a distance of 10cm for 20s to obtain the cured coating.

[0080] Appearance was determined visually; storage stability was assessed by visually observing changes in appearance after centrifugation at 3000 rpm for 15 minutes; pencil hardness was tested using the pencil hardness method according to GB / T 6739-2006 "Determination of Hardness of Paints and Varnishes by Pencil Method"; impact resistance was tested according to GB / T1732-1993 "Determination of Impact Resistance of Paint Films"; 50% thermal weight loss temperature and carbon yield were determined using a thermogravimetric analyzer. Approximately 8 mg of sample was weighed and placed in an aluminum crucible, with a heating rate of 10℃·min. -1 The test temperature range was 30℃ to 600℃, and high-purity nitrogen at a flow rate of 50 mL·min⁻¹ was used as the purge gas. Mechanical properties (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 defined as the percentage of bio-carbon content in the material or product relative to the total organic carbon in the product by weight (mass). The test results for each performance item are shown in Table 1.

[0081] Table 1. Performance test results of the aqueous bio-based photocurable materials prepared in Examples 1-3 and Comparative Examples 1-4

[0082]

[0083] As can be seen from Examples 1-3 in Table 1, the different waterborne bio-based photocurable materials based on organic-inorganic hybrid modification prepared by the method of the present invention have good storage stability, high pencil hardness, good impact resistance, good heat resistance, good mechanical properties, and high bio-based content. They have great application prospects in the field of waterborne bio-based photocurable materials, especially in the fields of food packaging, medicine and health, children's toys, automotive interiors, and high-end printing.

[0084] As shown in Table 1, the comparative analysis of Examples 1-3 and Comparative Example 1 reveals that the prepared waterborne bio-based photocurable materials, without the addition of modified nano-silica or without modification in step (4), exhibit poor pencil hardness, heat resistance, and mechanical properties. Furthermore, the bio-based content of Examples 1-3 and Comparative Example 1 is not significantly different, indicating that the introduction of modified nano-silica has a minimal impact on the bio-based content of the organic-inorganic hybrid modified waterborne bio-based photocurable materials. This demonstrates that modified nano-silica, which is photocurable and has good dispersibility and compatibility, provides a good reinforcing effect on waterborne bio-based photocurable materials, even with a small dosage. This further proves that the addition of modified nano-silica in step (4) of the preparation method is a necessary condition for improving the pencil hardness, heat resistance, and mechanical properties of the material.

[0085] The comparative analysis of Examples 1-3 and Comparative Example 2 in Table 1 shows that the water-based bio-based photocurable material prepared by adding unmodified nano-silica in step (4) of the preparation method has poor storage stability, heat resistance, and mechanical properties. Therefore, it is proven that the modification of nano-silica by isocyanate methacrylate in step (2) of the preparation method is a necessary condition for improving the storage stability, heat resistance, and mechanical properties of the material.

[0086] The comparative analysis of Examples 1-3 and Comparative Example 3 in Table 1 shows that the waterborne bio-based photocurable material prepared by adding glycidyl methacrylate (without alicyclic structure) in step (3) of the preparation method has poor pencil hardness, heat resistance, and mechanical properties. Therefore, it is proven that the introduction of 3,4-epoxycyclohexylmethyl methacrylate with alicyclic structure in step (3) of the preparation method is a necessary condition for improving the pencil hardness, heat resistance, and mechanical properties of the material.

[0087] The comparative analysis of Examples 1-3 and Comparative Example 4 in Table 1 shows that the pencil hardness, heat resistance, mechanical properties, and impact resistance of the waterborne bio-based photocurable materials prepared by adding glycidyl methacrylate (without alicyclic structure) in step (3) of the preparation method and adding unmodified nano-silica or unmodified nano-silica in step (4) of the preparation method are all poor. Therefore, it is proved that the introduction of 3,4-epoxycyclohexylmethyl methacrylate with alicyclic structure in step (3) of the preparation method and the addition of modified nano-silica in step (4) of the preparation method can synergistically improve the pencil hardness, heat resistance, and mechanical properties of the material, which is crucial for the material's performance.

[0088] 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 photocurable material based on organic-inorganic hybrid modification, characterized in that, Includes the following steps: Step 1: Dissolve and disperse nano-silica in acetone to obtain a nano-silica dispersion; Step 2: Under an inert atmosphere, the polymerization inhibitor and the nano silica dispersion are mixed, and then the modified functional monomer with monoisocyanate group and double bond is added. The mixture is heated to 50-70℃ and reacted for 2 hours. Then, dibutyltin dilaurate is added and the mixture is reacted at 50-70℃ for another 12 hours to obtain modified nano silica. Step 3: Under an inert atmosphere, citric acid, polymerization inhibitor, catalyst, and 1,4-dioxane are mixed, heated to 80-95℃ and kept at this temperature until the citric acid is completely dissolved. Then, methacrylate with an alicyclic structure is added dropwise and reacted for 0.5 hours. The temperature is then raised to 95-105℃ and the reaction continues until the acid value no longer changes. Epoxidized soybean oil is then added, and the reaction continues at 95-110℃ for 1 hour. The temperature is then controlled at 110℃ and the reaction continues until the acid value no longer changes. The reaction system temperature is then lowered to 80℃, and maleic anhydride is added, and the reaction continues until the acid value no longer changes. Step 4: Add modified nano-silica, stir until fully mixed, remove solvent by vacuum, then lower the temperature to 50-70℃, slowly add triethylamine, add deionized water under vigorous stirring and maintain for 0.5h, then filter to obtain the product; Step 5: Add photoinitiator, leveling agent and defoamer to the product while stirring, and mix evenly to obtain a water-based bio-based photocurable material based on organic-inorganic hybrid modification.

2. The preparation method according to claim 1, characterized in that, In steps 1-2, the mass percentages of each component are as follows:

3. The preparation method according to claim 2, characterized in that, In step 1, the nano-silica is hydrophilic fumed silica; In step 2, the modified functional monomer with monoisocyanate group and double bond is ethyl isocyanate methacrylate; In step 2, the polymerization inhibitor is one or a mixture of several of hydroquinone, p-benzoquinone, p-tert-butylcatechol, and p-methoxyphenol.

4. The preparation method according to claim 1, characterized in that, In steps 3-4, the mass percentages of each component are as follows:

5. The preparation method according to claim 4, characterized in that, In step 3, the polymerization inhibitors are all one or a mixture of several of hydroquinone, p-benzoquinone, p-tert-butylcatechol, and p-methoxyphenol; In step 3, the methacrylate with an alicyclic structure is 3,4-epoxycyclohexylmethyl methacrylate; In step 3, the catalyst is one of triphenylphosphine, N,N-dimethylaniline, N,N-dimethylbenzylamine, and tetrabutylammonium bromide.

6. The preparation method according to claim 1, characterized in that, In step 5, based on the mass of the product prepared in step 4, the mass percentage of the photoinitiator is 2-5%; the mass percentage of the leveling agent is 0.05-0.5%; and the mass percentage of the defoamer is 0.1-1%.

7. The preparation method according to claim 6, characterized in that, In step 5, the photoinitiator is one or more of 2-hydroxy-2-methyl-1-p-hydroxyethyl ether phenyl acetone, 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 photocurable material based on organic-inorganic hybrid modification prepared by the preparation method according to any one of claims 1-7.

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