Photocurable bio-based flame-retardant resin and preparation method thereof

Abstract

The invention provides a photocurable bio-based flame-retardant resin and a preparation method thereof, and belongs to the technical field of bio-based polymer flame-retardant materials.The preparation method comprises the steps that palm oil and phytic acid serve as raw materials, and palm oil-based methacrylate monomers and phytic acid-based methacrylate monomers are prepared respectively; palm oil-based methacrylate and phytic acid-based methacrylate are mixed with a photoinitiator through one-pot blending, the preparation method is simple and rapid, the obtained bio-based resin is environment-friendly, and an environment-friendly bio-based flame-retardant resin three-dimensional structure material can be prepared through ultraviolet light curing by utilizing an ultraviolet light 3D printing technology. Meanwhile, the plant oil-based resin has excellent mechanical strength, good deformability and efficient flame retardance, is also suitable for photocuring 3D printing, and can solve the technical bottlenecks that traditional plant oil-based resin is insufficient in mechanical property, low in deformation resistance, inflammable and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of bio-based polymer flame retardant materials, and in particular to a photocurable bio-based flame retardant resin and a preparation method thereof using biomass resources such as palm oil and phytic acid as raw materials. Background Art

[0002] With the improvement of environmental awareness and the requirements of sustainable development, the application of bio-based materials in the field of photocurable 3D printing is gradually increasing. Vegetable oil bio-based resources have significant renewability, can be continuously supplied and are widely sourced, reducing the dependence on limited fossil resources. Their production process generally has low energy consumption, and can be naturally degraded after use, being environmentally friendly, helping to reduce carbon emissions and environmental pollution. In addition, vegetable oils themselves have excellent properties, such as low volatility, high flash point, good lubricity, etc., and their chemical structure contains a unique triglyceride structure and various functional groups, and are widely used in fields such as construction, biofuels, bioplastics, lubricating oils, etc., promoting the green transformation of multiple industries. Palm oil is one of the vegetable oils with the largest production, consumption and international trade scale globally, and has significant characteristics such as being renewable, resource-rich and low-cost. However, the palm oil molecule contains an indefinite number of unsaturated double bonds, which often leads to insufficient mechanical strength of the resulting resin when directly chemically crosslinked, showing low mechanical properties and poor deformation resistance, and the alkyl carbon chains in palm oil are flammable and easily decomposed when heated. Phytic acid (PA) emerged as an environmentally friendly phosphorus-based flame retardant. It is derived from natural plants, is a sustainable resource, and helps to reduce the negative impact on the environment. The phosphorus carried by phytic acid accounts for about 80%-85% of the total phosphorus in plants, and is considered the main storage depot of phosphorus, with a phosphorus content of 28wt%, and is a very promising alternative phosphorus source. Phytic acid decomposes at a temperature of about 200°C, thereby promoting the dehydration of the carbon source to form a stable protective layer, forming a barrier between the flame and the combustible material, and is an important material to promote the sustainable development of the construction industry.

[0003] As a rapid prototyping technology, 3D printing technology has been widely used in fields such as construction, medical, and aerospace in recent years. However, traditional 3D printing materials are prone to deformation or combustion in high-temperature environments, restricting their application in scenarios with higher flame retardant requirements. Flame retardant resins not only need to meet the requirements of high precision, rapid prototyping and mechanical properties of 3D printing, but also need to have good flame retardant characteristics to address safety challenges in high-temperature environments. Therefore, developing 3D printing resins with excellent flame retardant properties has become a research hotspot. The ultraviolet light-curing 3D printing technology has become an ideal method for preparing complex-structured flame retardant resins due to its high efficiency, environmental friendliness and high precision. How to quickly prepare an environmentally friendly material with excellent plasticity, flame retardant properties and mechanical strength of a photocurable bio-based flame retardant resin is an urgent problem to be solved at present. Summary of the Invention

[0004] The object of the present invention is to solve the drawbacks existing in the prior art, and a photocurable bio-based flame retardant resin and a preparation method thereof are proposed. The preparation method is simple and rapid, and the obtained bio-based resin is environmentally friendly. At the same time, it has excellent mechanical strength, good deformability and high flame retardancy, and is also suitable for photocurable 3D printing, which can solve the technical bottlenecks such as insufficient mechanical properties, low anti-deformation ability and flammability of traditional vegetable oil-based resins.

[0005] To achieve the above object, the present invention adopts the following technical scheme: A photocurable bio-based flame retardant resin, the raw material composition components include, by mass: 0-50 parts of palm oil-based methacrylate, 50-100 parts of phytic acid-based methacrylate and 2 parts of initiator.

[0006] Further, the palm oil-based methacrylate is synthesized by an amidation reaction and an esterification reaction using palm oil, diethanolamine and methacrylic anhydride as raw materials; The phytic acid-based methacrylate is synthesized by an epoxy ring-opening reaction using phytic acid and glycidyl methacrylate as raw materials; The initiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0007] Further, the structural formula of the palm oil-based methacrylate is as follows: ; Wherein R1, R2, R3 are saturated or unsaturated fatty acids, and R1, R2, R3 are long-chain fatty acids. The flexibility of long-chain fatty acids can improve the impact resistance and ductility of the material, reduce the risk of brittle fracture, enhance the overall strength of the material, and form a three-dimensional network structure with the binding sites of carbonyl and amino groups, thereby improving the heat resistance and chemical stability of the material.

[0008] Further, the structural formula of the phytic acid-based methacrylate is: ; Wherein R is -H or a glycidyl methacrylate graft segment. The multi-functional group structure forms a denser network, improving the hardness and wear resistance of the material.

[0009] Further, it includes the following steps: S1: Using palm oil, diethanolamine and methacrylic anhydride as raw materials, synthesize palm oil-based methacrylate through an amidation reaction and an esterification reaction; S2: Using phytic acid and glycidyl methacrylate as raw materials, synthesize phytic acid-based methacrylate through an epoxy ring-opening reaction; accurately introduce methacrylate groups (double bonds) on the surface of phytic acid to make it have photocuring activity.

[0010] S3: Blend palm oil-based methacrylate, phytic acid-based methacrylate and photoinitiator, and after mixing evenly, prepare a photocurable bio-based flame retardant resin.

[0011] Furthermore, step S1 specifically includes: S11: Synthesize palm oil diethanolamide through amidation reaction; Mix 35 - 40 parts by mass of diethanolamine and 0.004 - 0.005 parts by mass of sodium methoxide, stir at 80 - 85 °C for 30 - 35 min under a nitrogen atmosphere, then add 60 - 65 parts by mass of palm oil, stir at 120 - 130 °C for 4 - 5 h, cool to room temperature, mix with ethyl acetate, add saturated sodium chloride solution and purify repeatedly for 5 - 8 times, and then rotary evaporate and purify for 2 - 3 h to obtain palm oil diethanolamide; Introduce polar groups such as hydroxyl and amino groups through the amidation reaction, enhance the active sites of the subsequent esterification reaction, and provide an efficient and flexible preparation route for palm oil-based methacrylate.

[0012] S12: Synthesize palm oil-based methacrylate through esterification reaction; Stir palm oil diethanolamide, methacrylic anhydride, hydroquinone, 4-dimethylaminopyridine at 60 - 65 °C for 5 - 6 h, cool to room temperature, purify with saturated sodium bicarbonate solution for 5 - 8 times, and then rotary evaporate and purify for 1 - 2 h to obtain palm oil-based methacrylate. The palm oil-based methacrylate generated by the esterification reaction forms a three-dimensional network structure through free radical polymerization, significantly improving the hardness, heat resistance and impact strength of the material.

[0013] Furthermore, the mass ratio of palm oil diethanolamide, methacrylic anhydride, hydroquinone, 4-dimethylaminopyridine is 10:15:0.052:0.20.

[0014] Furthermore, step S2 specifically includes: Stir and react phytic acid, glycidyl methacrylate, inhibitor, catalyst at 85 ± 5 °C for 1 - 2 h, extract and separate with ethyl acetate, and rotary evaporate to obtain phytic acid-based methacrylate; The mass ratio of phytic acid, glycidyl methacrylate, inhibitor, catalyst is 1:1.94:0.0029:0.029.

[0015] Further, the inhibitor is hydroquinone; the catalyst is tetrabutylammonium bromide. The catalytic rate is high, shortening the reaction time to within 4.5 hours to achieve rapid preparation. Hydroquinone captures free radicals, effectively inhibiting the self-polymerization tendency of glycidyl methacrylate at high temperatures, avoiding excessive local cross-linking density and making the distribution of cross-linking points more uniform. This results in a more uniform molecular weight distribution of the product, reducing stress concentration points caused by differences in chain segment length, thereby improving flexibility. It can also ensure the integrity of the C=C double bond. The complete retention of the double bond enables the cured material to achieve a balance between cross-linking density and chain segment mobility. In subsequent photocuring, the double bond fully participates, forming a three-dimensional network with both strength and flexibility.

[0016] Further, the mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate is 3:7 to 4:6; the dosage of the initiator is 2% of the total mass of the resin.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The bio-based photocurable resin prepared in the present invention uses palm oil and phytic acid, which are rich in yield, low in price, and green and harmless, as raw materials, and is an environmentally friendly material; this bio-based photocurable resin not only has excellent plasticity, flame retardancy, and mechanical strength, but also achieves flame retardancy through the synergistic effect of palm oil and phytic acid, creating a new method for preparing flame-retardant photocurable polymers.

[0018] (2) By optimizing the process parameter combination, the present invention forms a blend of phytic acid-based methacrylate, palm oil-based methacrylate, and a photoinitiator, and uses ultraviolet light with a wavelength of 365 nm in a 3D printer to cure at a printing speed of 20 mm / h, successfully preparing a bio-based photocurable resin with excellent comprehensive properties. It can be seen that the bio-based photocurable resin of the present invention is suitable for photocurable 3D printing and can quickly prepare a three-dimensional structural material with excellent mechanical strength, good deformability, and high flame retardancy effect. By combining the bio-based resin with a photoinitiator and using ultraviolet light curing technology, a three-dimensional structural material with high mechanical properties and excellent flame retardancy effect can be quickly prepared. This material can not only meet the high-precision requirements of building models, customized components, etc., but also be used for the manufacture of functional components in high-temperature environments such as fire-fighting equipment, providing new solutions for the construction industry and the fire-fighting field. Description of the Drawings

[0019] Figure 1 It is the synthesis reaction route diagram of the palm oil-based methacrylate of the present invention; Figure 2 It is the synthesis reaction route diagram of the phytic acid-based methacrylate of the present invention; Figure 3 It is the flexural stress-deflection curve of the bio-based photocurable flame-retardant resin in the embodiment of the present invention; Figure 4 It is a vertical combustion process diagram of the bio-based photocurable flame-retardant resin in the embodiment of the present invention.

[0020] Among them, M 50 G 50 represents a photocurable resin with a mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate of 5:5; M 40 G 60 represents a photocurable resin with a mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate of 4:6; M 30 G 70 represents a photocurable resin with a mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate of 3:7; M 20 G 80 represents a photocurable resin with a mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate of 2:8; M 10 G 90 represents a photocurable resin with a mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate of 1:9; M0G 100 represents a photocurable resin prepared from phytic acid-based methacrylate as a raw material. Specific embodiments

[0021] To further understand the purpose, structure, characteristics, and functions of the present invention, the technical solutions of the present invention will be clearly and completely described in conjunction with the attached Figures 1-4 and specific embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be purchased commercially.

[0022] Raw materials: 18-degree palm oil was purchased from Shanghai Dingfen Chemical Technology Co., Ltd., China; diethanolamine, methacrylic anhydride, tetrabutylammonium bromide, 4-dimethylaminopyridine, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide were purchased from Shanghai Jingchun (Aladdin) Industrial Co., Ltd.; sodium chloride, ethyl acetate, hydroquinone, sodium methoxide, and sodium bicarbonate were purchased from Shanghai National Pharmaceutical Group Chemical Reagent Co., Ltd.; phytic acid and glycidyl methacrylate were purchased from Shanghai Macklin Biochemical Technology Co., Ltd.

[0023] Synthesis of palm oil-based methacrylate, synthesis process: Add 249.8 g of diethanolamine and 3.24 g of sodium methoxide into a flask, and introduce nitrogen gas. Set the oil bath to 80 °C, stir mechanically (250 r / min) for 30 min, then add 400 g of palm oil and raise the temperature of the oil bath to 120 °C. Continue to stir (250 r / min) for 4 h and then cool to room temperature. Mix evenly with 500 mL of ethyl acetate, add 2 L of saturated sodium chloride solution and purify repeatedly for 5 - 8 times, then rotary evaporate and purify for 2 h to obtain palm oil diethanolamide. Add 100 g of palm oil diethanolamide, 150 g of methacrylic anhydride, 0.52 g of hydroquinone and 1.99 g of 4-dimethylaminopyridine into the flask respectively. Set the temperature of the oil bath to 60 °C and stir mechanically (250 r / min) for 5 h. After stirring, cool it. After cooling to room temperature, purify it with 2 L of saturated sodium bicarbonate solution for 5 - 8 times, then rotary evaporate and purify for 1 h to obtain palm oil-based methacrylate. The synthesis reaction route is as Figure 1 shown.

[0024] Synthesis of phytic acid-based methacrylate, synthesis process: Preheat a 500 mL three-necked flask equipped with a condenser in an 85 °C oil bath. Then add 66 g of phytic acid, 128 g of glycidyl methacrylate, 0.19 g of inhibitor hydroquinone and 1.9 g of catalyst tetrabutylammonium bromide into the flask in sequence. Stir and react mechanically at a speed of 250 r / min for 1 h, cool to room temperature, extract and separate with 200 mL of ethyl acetate, and rotary evaporate to obtain phytic acid-based methacrylate. The synthesis reaction route is as Figure 2 shown. Example 1

[0025] Preparation of photocurable bio-based flame retardant resin: Uniformly mix 25 g of palm oil-based methacrylate, 25 g of phytic acid-based methacrylate and 1 g of photoinitiator to obtain a photocurable bio-based flame retardant resin. In the preparation process of this example, the mass ratio of the amount of palm oil-based methacrylate to phytic acid-based methacrylate is 5:5; the amount of the initiator is 2% of the total mass of the resin.

[0026] Photocurable resin prepared by 3D printing: Pour the photocurable bio-based flame retardant resin prepared in this example into a UV-treated 3D printer, and print at a speed of 20 mm / h under UV light irradiation with a wavelength of 365 nm according to the set program. Example 2

[0027] Preparation of photocurable bio-based flame retardant resin: 20 g of palm oil-based methacrylate, 30 g of phytic acid-based methacrylate, and 1 g of photoinitiator were uniformly mixed to obtain a photocurable bio-based flame retardant resin. During the preparation process of this example, the mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate was 4:6; the dosage of the initiator was 2% of the total mass of the resin.

[0028] Photocurable resin prepared by 3D printing: The photocurable bio-based flame retardant resin prepared in this example was poured into a 3D printer treated with ultraviolet light. According to the set program, under the irradiation of ultraviolet light with a wavelength of 365 nm, printing was carried out at a speed of 20 mm / h. Example 3

[0029] Preparation of photocurable bio-based flame retardant resin: 15 g of palm oil-based methacrylate, 35 g of phytic acid-based methacrylate, and 1 g of photoinitiator were uniformly mixed to obtain a photocurable bio-based flame retardant resin. During the preparation process of this example, the mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate was 3:7; the dosage of the initiator was 2% of the total mass of the resin.

[0030] Photocurable resin prepared by 3D printing: The photocurable bio-based flame retardant resin prepared in this example was poured into a 3D printer treated with ultraviolet light. According to the set program, under the irradiation of ultraviolet light with a wavelength of 365 nm, printing was carried out at a speed of 20 mm / h. Example 4

[0031] Preparation of photocurable bio-based flame retardant resin: 10 g of palm oil-based methacrylate, 40 g of phytic acid-based methacrylate, and 1 g of photoinitiator were uniformly mixed to obtain a photocurable bio-based flame retardant resin. During the preparation process of this example, the mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate was 2:8; the dosage of the initiator was 2% of the total mass of the resin.

[0032] Photocurable resin prepared by 3D printing: The photocurable bio-based flame retardant resin prepared in this example was poured into a 3D printer treated with ultraviolet light. According to the set program, under the irradiation of ultraviolet light with a wavelength of 365 nm, printing was carried out at a speed of 20 mm / h. Example 5

[0033] Preparation of photocurable bio-based flame retardant resin: 5 g of palm oil-based methacrylate, 45 g of phytic acid-based methacrylate and 1 g of photoinitiator were uniformly mixed to obtain a photocurable bio-based flame retardant resin. In the preparation process of this example, the mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate was 1:9; the dosage of the initiator was 2% of the total mass of the resin.

[0034] Photocurable resin prepared by 3D printing: The photocurable bio-based flame retardant resin prepared in this example was poured into a 3D printer treated with ultraviolet light. According to the set program, it was printed at a speed of 20 mm / h under ultraviolet light with a wavelength of 365 nm. Example 6

[0035] 50 g of phytic acid-based methacrylate and 1 g of photoinitiator were uniformly mixed to obtain a photocurable bio-based flame retardant resin. In the preparation process of this example, the mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate was 0:10; the dosage of the initiator was 2% of the total mass of the resin.

[0036] Photocurable resin prepared by 3D printing: The photocurable bio-based flame retardant resin prepared in this example was poured into a 3D printer treated with ultraviolet light. According to the set program, it was printed at a speed of 20 mm / h under ultraviolet light with a wavelength of 365 nm.

[0037] Product performance testing: 1. Mechanical property testing of the resin: The resin was made into dumbbell-shaped specimens (specification: total length 75 mm, width 12.5 mm at both ends, width 4 mm in the middle, length 25 mm in the middle, thickness 3 mm) to test the tensile properties, and the tensile property testing was carried out according to the ASTM D638-10 standard; the resin was made into rectangular specimens (specification: length 80 mm, width 10 mm, thickness 3 mm) for bending property testing; both the tensile property and bending property testing were completed on a microcomputer-controlled electronic universal testing machine. The specific data are shown in Table 1 and Figure 3 As shown, where Table 1 shows the tensile and bending property parameters of the bio-based photocurable flame retardant resins prepared in Examples 1-6:

[0038] As can be seen from Table 1, for the photocurable polymer copolymerized from palm oil-based methacrylate and phytic acid-based methacrylate: its tensile strength, tensile modulus, bending strength and bending modulus all gradually decrease with the increase in the dosage of phytic acid-based methacrylate, while the elongation at break gradually increases with the increase in the dosage of phytic acid-based methacrylate.

[0039] Figure 3Flexural stress-deflection curves of the bio-based photocurable flame-retardant resins prepared in Examples 1-6; as Figure 3 known, the flexural fracture strength of the photocurable flame-retardant resin shows an increasing trend with the increase in the amount of palm oil-based methacrylate, but the flexural fracture deflection shows a trend of first decreasing and then increasing with the amount of palm oil-based methacrylate, and M 50 G 50 has the maximum flexural strength, and M 30 G 70 has the maximum flexural fracture deflection, indicating that the resin has good anti-deformation ability.

[0040] 2. Gel content test of the resin: The gel content was determined by the solvent extraction method of GB / T 37498-2019, and the solvent was toluene.

[0041] 3. Glass transition temperature test of the resin: The rectangular resin sample (length 30 mm, width 10 mm, thickness 2 mm) was tested on a Q800 dynamic mechanical analyzer (TA Instruments, USA) under the condition of alternating stress at a fixed frequency with a certain heating rate; the test was carried out in single-cantilever mode in an air atmosphere, with a frequency of 1 Hz, a temperature range of -50 °C to 150 °C, and a heating rate of 5 °C / min.

[0042] 4. Limiting oxygen index (LOI) test of the resin: The LOI test was carried out according to the test method of ASTM D 2863-97 on an FTT0077 type limiting oxygen index instrument (UK), and the specimen size was 100 × 12.5 × 3 mm 3 . When the oxygen index is lower than 22%, it belongs to flammable materials; when the oxygen index is between 22% and 27%, it belongs to combustible materials; when the oxygen index is higher than 27%, it belongs to flame-retardant materials.

[0043] 5. Vertical burning (UL-94) test of the resin: The vertical burning test was carried out according to the UL-94 test method on a Suzhou Yangyi Wolqi VOUCH 5402 instrument, and the combustion process was recorded by a digital camera. The specimen size was 125 × 10 × 3 mm 3 . UL-94 is mainly divided into V0, V1, and V2 grades, among which the V0 grade corresponds to the highest flame-retardant grade.

[0044] The specific vertical burning process is as Figure 4 shown. From Figure 4 it can be observed the vertical burning process of the bio-based photocurable flame-retardant resin. In polymer M 50 G 50During the vertical burning test, the first ignition of the sample strip was instantly extinguished, and the second ignition of the sample strip could not self-extinguish; in Polymer M 40 G 60 During the vertical burning test, both the first and second ignitions for 10 s were instantly extinguished, meeting the UL-94 V0 grade. As the dosage of phytic acid-based methacrylate increased, the flame retardancy of the polymer became more excellent.

[0045] The gel content, glass transition temperature, limiting oxygen index, and UL-94 rating of the bio-based photocurable flame retardant resin are shown in Table 2 below:

[0046] As can be seen from Table 2, the glass transition temperatures of the photocurable flame retardant resins M 50 G 50 、M 40 G 60 and M 30 G 70 are 107.4 °C, 101.6 °C, and 81.0 °C respectively, and the gel contents are 98.3%, 98.1%, and 96.9% respectively. As the dosage of palm oil-based methacrylate increased, both the glass transition temperature and gel content of the polymer showed an increasing trend. The limiting oxygen indices of the photocurable polymers M 50 G 50 、M 40 G 60 and M 30 G 70 are 25.8%, 30.44%, and 31.4% respectively, and the UL-94 ratings are NR, V0, and V0 grades respectively; as the dosage of phytic acid-based methacrylate increased, the limiting oxygen index of the polymer showed an increasing trend, and the flame retardant effect was also getting better.

[0047] In summary, the present invention uses biomass palm oil and phytic acid as raw materials, and through the amidation, esterification reaction of palm oil and the ring-opening reaction of phytic acid, synthesizes highly reactive monomers that can participate in free radical polymerization; copolymerizes the two highly active photosensitive monomers in one-pot method. The test results of mechanical strength, glass transition temperature, and flame retardancy show that the resin has good mechanical properties and flame retardant effect, and can solve the technical bottlenecks such as insufficient mechanical properties, low anti-deformation ability, and flammability of traditional vegetable oil-based resins.

[0048] Therefore, the bio-based resin prepared by the present invention is environmentally friendly, suitable for photocuring 3D printing, and at the same time has excellent mechanical strength, good deformability and high flame retardancy. It is suitable for photocuring 3D printing and can solve the technical bottlenecks of traditional vegetable oil-based resins, such as insufficient mechanical properties, low anti-deformation ability and flammability. At the same time, the preparation of this resin makes full use of bio-based raw materials, greatly expanding the efficient utilization ways of palm oil and phytic acid in the field of flame retardancy. It can not only reduce the dependence on fossil raw materials, but also promote the development of the country's low-carbon economy.

[0049] The present invention has been described by the above related embodiments. However, the above embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, all changes and modifications made without departing from the spirit and scope of the present invention fall within the scope of patent protection of the present invention.

Claims

1. A photocurable bio-based flame-retardant resin, characterized in that: The raw material components include, by weight: 0-50 parts of palm oil-based methacrylate, 50-100 parts of phytic acid-based methacrylate and 2 parts of initiator.

2. The photocurable bio-based flame retardant resin according to claim 1, characterized in that: The palm oil-based methacrylate is synthesized from palm oil, diethanolamine and methacrylic anhydride through amidation and esterification reactions; The phytic acid-based methacrylate is synthesized by using phytic acid and glycidyl methacrylate as raw materials through an epoxy ring-opening reaction; The initiator is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

3. The photocurable bio-based flame-retardant resin according to claim 1, wherein: The structural formula of the palm oil-based methacrylate is as follows: ； Wherein R1, R2, R3 are saturated or unsaturated fatty acids.

4. The photocurable bio-based flame-retardant resin according to claim 1, wherein: The structural formula of the phytyl methacrylate is: ； Wherein R is -H or a glycidyl methacrylate grafting segment.

5. A method for preparing a photocurable bio-based flame retardant resin according to any one of claims 1-5, characterized in that: The following steps are involved: S1: Palm oil-based methacrylate was synthesized by amidation and esterification using palm oil, diethanolamine and methacrylic anhydride as raw materials; S2: Phytic acid and glycidyl methacrylate were used as raw materials to synthesize phytic acid-based methacrylate through epoxy ring-opening reaction; S3: Palm oil-based methacrylate, phytic acid-based methacrylate and a photoinitiator are blended and mixed evenly to prepare a photocurable bio-based flame retardant resin.

6. The preparation method of the photocurable bio-based flame retardant resin according to claim 5, characterized in that: Step S1 specifically includes: S11: Synthesis of palm oil diethanolamide by amidation reaction; Mix 35-40 parts by weight and 0.004-0.005 parts by weight of diethanolamine and sodium methoxide, stir at 80-85° C. for 30-35 minutes under a nitrogen environment, add 60-65 parts by weight of palm oil, stir at 120-130° C. for 4-5 hours, cool to room temperature, mix with ethyl acetate, add saturated sodium chloride solution and purify repeatedly for 5-8 times, and purify by rotary evaporation for 2-3 hours to obtain palm oil diethanolamide; S12: Synthesis of palm oil-based methacrylate by esterification reaction; Palm oil diethanolamide, methacrylic anhydride, hydroquinone and 4-dimethylaminopyridine are stirred at 60-65°C for 5-6 hours, cooled to room temperature, purified by saturated sodium bicarbonate solution for 5-8 times, and then rotary evaporated for 1-2 hours to obtain palm oil-based methacrylate.

7. The preparation method of the photocurable bio-based flame retardant resin according to claim 6, characterized in that: The mass ratio of palm oil diethanolamide, methacrylic anhydride, hydroquinone and 4-dimethylaminopyridine is 10:15:0.052:0.

20.

8. The preparation method of the photocurable bio-based flame retardant resin according to claim 1, characterized in that: Step S2 specifically includes: Phytic acid, glycidyl methacrylate, inhibitor and catalyst are stirred and reacted at 85±5°C for 1-2h, extracted with ethyl acetate, and rotary evaporated to obtain phytic acid methacrylate; the mass ratio of phytic acid, glycidyl methacrylate, inhibitor and catalyst is 1:1.94:0.0029:0.

029.

9. The preparation method of the photocurable bio-based flame retardant resin according to claim 8, characterized in that: The polymerization inhibitor is hydroquinone; and the catalyst is tetrabutylammonium bromide.

10. The preparation method of the photocurable bio-based flame retardant resin according to claim 5, characterized in that: The mass ratio of palm oil-based methacrylate to phytic acid-based methacrylate is 3:7-4:6; the amount of the initiator used is 2% of the total mass of the resin.

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