Ultraviolet-proof degradable film for corn for seed production and preparation method of ultraviolet-proof degradable film

Abstract

The invention relates to the technical field of high polymer materials, and discloses an anti-ultraviolet degradation film for seed corn and a preparation method thereof.The preparation method comprises the following steps that poly (butylene adipate-co-terephthalate), polylactic acid, barrier master batches, modified benzophenone, an ultraviolet light absorber, an antioxidant 1010 and stearic acid are put into a high-speed mixer to be mixed for 20-40 min at the speed of 2000-3000 rpm, and a mixture is obtained; the preparation method comprises the following steps: mixing the raw materials to obtain a primary mixed material, adding the obtained primary mixed material into a double-screw extruder, extruding and granulating at 140-160 DEG C, then putting the obtained master batch into a film blowing machine, and carrying out film blowing molding at 160-190 DEG C to obtain the ultraviolet-proof degradable film for the corn for seed production. The degradable film disclosed by the invention has good anti-ultraviolet performance and antibacterial performance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a UV-resistant degradable film for seed corn and its preparation method. Background Technology

[0002] Seed corn plays a vital role in agricultural production, as its seed quality directly impacts the yield and quality of subsequent corn crops. During seed production, plastic film mulching is widely used as an important agricultural cultivation measure to ensure flowering coincidence, improve pollination rates, and optimize the growing environment, enabling scientific management of seed corn fields. However, traditional plastic film is prone to photo-oxidative degradation over long-term use, especially under high temperature and strong sunlight conditions. It cannot effectively shield against ultraviolet radiation, which has high energy and can damage nucleic acids, proteins, and photosynthetic pigments in plant cells, leading to pollen inactivation, reduced pollination rates, and consequently affecting the overall seed quality. Therefore, avoiding this phenomenon is crucial. For example, patent CN120441886A discloses a biodegradable bagasse mulch film loaded with phosphate rock powder and its preparation and application. This invention features a low-cost, simple process, and controllable degradation rate, making it suitable for large-scale production and promotion, and offering good ecological, economic, and social benefits. However, its UV resistance needs improvement. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a UV-resistant degradable film for seed corn production and its preparation method. The degradable film of this invention has excellent UV resistance and antibacterial properties.

[0004] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a UV-resistant degradation film for seed corn, comprising the following weight components: 70-80 parts by weight of poly(butylene adipate / terephthalate), 8-12 parts by weight of polylactic acid, 5-7 parts by weight of barrier masterbatch, 1-3 parts by weight of modified benzophenone, 2-4 parts by weight of UV absorber, 0.3-0.5 parts by weight of antioxidant 1010, and 0.2-0.4 parts by weight of stearic acid; The method for preparing the modified benzophenone is as follows: Step 1: o-Fluorobenzophenone reacts with 9,10-dihydro-9,9-dimethylacridine to give intermediate 1; Step 2: Intermediate 1 reacts with N-bromosuccinimide to obtain intermediate 2; Step 3: Intermediate 2 reacts with N,N-dimethylhexadecanine to obtain modified benzophenone; The method for preparing the ultraviolet absorber is as follows: 4-Hydroxybenzophenone reacts with 3,3-dithiodipropionic acid to yield an ultraviolet absorber.

[0005] Furthermore, the method for preparing the modified benzophenone is as follows: Step 1: Under nitrogen protection, o-fluorobenzophenone, 9,10-dihydro-9,9-dimethylacridine, and sodium hydride were added to tetrahydrofuran solvent and stirred until homogeneous. The mixture was reacted at 65-75℃ for 22-26 hours. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, and the mixture was washed and dried. The residue was separated by column chromatography to obtain intermediate 1. Step 2: Add intermediate 1 to chloroform solvent, stir and mix, slowly add N-bromosuccinimide dropwise at 0-5℃, then move the reaction system to room temperature and react in the dark for 10-14 hours. After the reaction is completed, evaporate the solvent, filter and obtain intermediate 2. Step 3: Add intermediate 2 and N,N-dimethylhexadecanine to N,N-dimethylformamide solvent, stir and mix, and reflux at 60-80℃ for 20-25 h. After the reaction is completed, recrystallize and dry to obtain modified benzophenone.

[0006] Furthermore, in step one, the ratio of tetrahydrofuran, o-fluorobenzophenone, 9,10-dihydro-9,9-dimethylacridine, and sodium hydride is 90-100mL:3-3.05g:3.92-3.96g:1.2-1.24g.

[0007] Furthermore, in step two, the ratio of chloroform, intermediate 1, and N-bromosuccinimide is 60-80 mL: 0.84-0.88 g: 0.74-0.76 g.

[0008] Furthermore, in step three, the ratio of N,N-dimethylformamide, intermediate 2, and N,N-dimethylhexadecanamide is 15-20 mL: 0.42-0.46 g: 0.53-0.57 g.

[0009] Further, the method for preparing the ultraviolet absorber is as follows: 4-hydroxybenzophenone and 3,3-dithiodipropionic acid are added to a pyridine solvent and stirred until homogeneous. Then, p-toluenesulfonic acid and dicyclohexylcarbodiimide are added to the solvent and reacted at 30-50°C for 6-8 hours. After the reaction is completed, the solvent is removed by rotary evaporation, and the solvent is washed and dried to obtain the ultraviolet absorber.

[0010] Further, the ratio of pyridine, 4-hydroxybenzophenone, 3,3-dithiodipropionic acid, p-toluenesulfonic acid, and dicyclohexylcarbodiimide is 40-60 mL: 0.58-0.62 g: 0.31-0.35 g: 0.01-0.02 g: 0.01-0.03 g.

[0011] Further, the preparation method of the UV-resistant degradable film for seed corn is as follows: Poly(butylene adipate / terephthalate), polylactic acid, barrier masterbatch, modified benzophenone, UV absorber, antioxidant 1010 and stearic acid are put into a high-speed mixer and mixed at 2000-3000 rpm for 20-40 min to obtain a preliminary mixture. The obtained preliminary mixture is added to a twin-screw extruder and extruded at 140-160℃ to granulate. Then, the obtained masterbatch is fed into a blown film machine and blown into a film at 160-190℃ to obtain the UV-resistant degradable film for seed corn.

[0012] (iii) Beneficial technical effects This invention obtains intermediate 1 by reacting o-fluorobenzophenone with 9,10-dihydro-9,9-dimethylacridine. The unique conjugated structure of o-fluorobenzophenone allows the energy required for the transition between its electronic energy levels to match the energy of ultraviolet light, resulting in strong absorption of high-energy ultraviolet light. This absorption energy is then converted into harmless heat energy and released, enhancing the UV resistance of the degradation film. The 9,10-dihydro-9,9-dimethylacridine structure efficiently captures and scavenges free radicals induced by ultraviolet light, interrupting the chain reaction that leads to polymer chain breakage and protecting the mechanical properties of the degradation film from damage. The subsequent intermediate 3 introduces quaternary ammonium salt groups, which can effectively inhibit the growth of mold and bacteria, keep the material surface clean, and enhance the antibacterial properties of the degradation film. The lipophilic long carbon chain on N,N-dimethylhexadecanamine improves the compatibility of the material. The esterification reaction of 4-hydroxybenzophenone and 3,3-dithiodipropionic acid yields an ultraviolet absorber. The introduction of ester groups can enhance the ultraviolet absorption capacity of benzophenone in the 260-400nm wavelength band, improve the UV resistance of the degradation film, and the disulfide bond can provide peroxide decomposition and auxiliary antioxidant capacity, thereby improving the weather resistance of the degradation film. Attached Figure Description

[0013] Figure 1 This is the synthetic reaction formula for modified benzophenone.

[0014] Figure 2 It is the synthesis reaction formula for ultraviolet absorbers. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0016] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0017] The reagents used in the following specific embodiments are of analytical grade. Additionally: Polybutylene adipate / butylene terephthalate: Grade TH801T; Polylactic acid: grade LX175; Barrier masterbatch: grade L171B.

[0018] Example 1 (1) Under nitrogen protection, 3g of o-fluorobenzophenone, 3.92g of 9,10-dihydro-9,9-dimethylacridine and 1.2g of sodium hydride were added to 90mL of tetrahydrofuran solvent. The mixture was stirred until homogeneous and reacted at 65℃ for 22h. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, the mixture was washed and dried, and separated by column chromatography to obtain intermediate 1. (2) Add 0.84 g of intermediate 1 to 60 mL of chloroform solvent, stir and mix, and slowly add 0.74 g of N-bromosuccinimide at 0 °C. Then, move the reaction system to room temperature and react in the dark for 10 h. After the reaction is completed, evaporate the solvent, filter and obtain intermediate 2. (3) Add 0.42 g of intermediate 2 and 0.53 g of N,N-dimethylhexadecanine to 15 mL of N,N-dimethylformamide solvent, stir and mix, reflux at 60 °C for 20 h, recrystallize and dry to obtain modified benzophenone; (4) Add 0.58 g of 4-hydroxybenzophenone and 0.31 g of 3,3-dithiodipropionic acid to 40 mL of pyridine solvent, stir evenly, then add 0.01 g of p-toluenesulfonic acid and 0.01 g of dicyclohexylcarbodiimide, react at 30 °C for 6 h, after the reaction is completed, remove the solvent by rotary evaporation, wash and dry to obtain the ultraviolet absorber; (5) 70 parts by weight of poly(butylene adipate / terephthalate), 8 parts by weight of polylactic acid, 5 parts by weight of barrier masterbatch, 1 part by weight of modified benzophenone, 2 parts by weight of ultraviolet absorber, 0.3 parts by weight of antioxidant 1010 and 0.2 parts by weight of stearic acid are put into a high-speed mixer and mixed at 2000 rpm for 20 min to obtain a preliminary mixture. The obtained preliminary mixture is added to a twin-screw extruder and extruded at 140°C to granulate. Then the obtained masterbatch is put into a blown film machine and blown at 160°C to obtain a UV-resistant degradable film for seed corn.

[0019] Example 2 (1) Under nitrogen protection, 3.05 g of o-fluorobenzophenone, 3.96 g of 9,10-dihydro-9,9-dimethylacridine and 1.24 g of sodium hydride were added to 100 mL of tetrahydrofuran solvent. The mixture was stirred until homogeneous and reacted at 75 °C for 26 h. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, the mixture was washed and dried, and separated by column chromatography to obtain intermediate 1. (2) Add 0.88 g of intermediate 1 to 80 mL of chloroform solvent, stir and mix, and slowly add 0.76 g of N-bromosuccinimide at 5 °C. Then, move the reaction system to room temperature and react in the dark for 14 h. After the reaction is completed, evaporate the solvent, filter and obtain intermediate 2. (3) Add 0.46 g of intermediate 2 and 0.57 g of N,N-dimethylhexadecanine to 20 mL of N,N-dimethylformamide solvent, stir and mix, reflux at 80 °C for 25 h, recrystallize and dry to obtain modified benzophenone; (4) Add 0.62 g of 4-hydroxybenzophenone and 0.35 g of 3,3-dithiodipropionic acid to 60 mL of pyridine solvent, stir evenly, then add 0.02 g of p-toluenesulfonic acid and 0.03 g of dicyclohexylcarbodiimide, react at 50 °C for 8 h, after the reaction is completed, remove the solvent by rotary evaporation, wash and dry to obtain the ultraviolet absorber; (5) 80 parts by weight of poly(butylene adipate / terephthalate), 12 parts by weight of polylactic acid, 7 parts by weight of barrier masterbatch, 3 parts by weight of modified benzophenone, 4 parts by weight of ultraviolet absorber, 0.5 parts by weight of antioxidant 1010 and 0.4 parts by weight of stearic acid are put into a high-speed mixer and mixed at 3000 rpm for 40 min to obtain a preliminary mixture. The obtained preliminary mixture is added to a twin-screw extruder and extruded at 160°C to granulate. Then the obtained masterbatch is put into a blown film machine and blown at 190°C to obtain a UV-resistant degradable film for seed corn.

[0020] Example 3 (1) Under nitrogen protection, 3.02 g of o-fluorobenzophenone, 3.94 g of 9,10-dihydro-9,9-dimethylacridine and 1.22 g of sodium hydride were added to 95 mL of tetrahydrofuran solvent. The mixture was stirred until homogeneous and reacted at 70 °C for 24 h. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, the mixture was washed and dried, and separated by column chromatography to obtain intermediate 1. (2) Add 0.86 g of intermediate 1 to 70 mL of chloroform solvent, stir and mix, and slowly add 0.75 g of N-bromosuccinimide at 2 °C. Then, move the reaction system to room temperature and react in the dark for 12 h. After the reaction is completed, evaporate the solvent and filter to obtain intermediate 2. (3) Add 0.44 g of intermediate 2 and 0.55 g of N,N-dimethylhexadecanine to 18 mL of N,N-dimethylformamide solvent, stir and mix, reflux at 70 °C for 22 h, recrystallize and dry to obtain modified benzophenone; (4) Add 0.6 g of 4-hydroxybenzophenone and 0.33 g of 3,3-dithiodipropionic acid to 50 mL of pyridine solvent, stir evenly, then add 0.01 g of p-toluenesulfonic acid and 0.02 g of dicyclohexylcarbodiimide, react at 40 °C for 7 h, after the reaction is completed, remove the solvent by rotary evaporation, wash and dry to obtain the ultraviolet absorber; (5) 75 parts by weight of poly(butylene adipate / terephthalate), 10 parts by weight of polylactic acid, 6 parts by weight of barrier masterbatch, 2 parts by weight of modified benzophenone, 3 parts by weight of ultraviolet absorber, 0.4 parts by weight of antioxidant 1010 and 0.3 parts by weight of stearic acid are put into a high-speed mixer and mixed at 2500 rpm for 30 min to obtain a preliminary mixture. The obtained preliminary mixture is added to a twin-screw extruder and extruded at 150°C to granulate. Then the obtained masterbatch is put into a blown film machine and blown at 175°C to obtain a UV-resistant degradable film for seed corn.

[0021] Example 4 (1) Under nitrogen protection, 3.01 g of o-fluorobenzophenone, 3.93 g of 9,10-dihydro-9,9-dimethylacridine and 1.21 g of sodium hydride were added to 92 mL of tetrahydrofuran solvent. The mixture was stirred until homogeneous and reacted at 68 °C for 23 h. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, the mixture was washed and dried, and separated by column chromatography to obtain intermediate 1. (2) Add 0.85 g of intermediate 1 to 65 mL of chloroform solvent, stir and mix, and slowly add 0.74 g of N-bromosuccinimide at 1 °C. Then, move the reaction system to room temperature and react in the dark for 11 h. After the reaction is completed, evaporate the solvent, filter and obtain intermediate 2. (3) Add 0.43 g of intermediate 2 and 0.54 g of N,N-dimethylhexadecylamine to 16 mL of N,N-dimethylformamide solvent, stir and mix, and reflux at 65 °C for 21 h. After the reaction is completed, recrystallize and dry to obtain modified benzophenone. (4) Add 0.59 g of 4-hydroxybenzophenone and 0.32 g of 3,3-dithiodipropionic acid to 45 mL of pyridine solvent, stir evenly, then add 0.01 g of p-toluenesulfonic acid and 0.01 g of dicyclohexylcarbodiimide, and react at 35 °C for 6 h. After the reaction is completed, remove the solvent by rotary evaporation, wash and dry to obtain the ultraviolet absorber. (5) 72 parts by weight of poly(butylene adipate / terephthalate), 9 parts by weight of polylactic acid, 5 parts by weight of barrier masterbatch, 1 part by weight of modified benzophenone, 3 parts by weight of ultraviolet absorber, 0.3 parts by weight of antioxidant 1010 and 0.2 parts by weight of stearic acid are put into a high-speed mixer and mixed at 2200 rpm for 25 min to obtain a preliminary mixture. The obtained preliminary mixture is added to a twin-screw extruder and extruded at 145°C to granulate. Then the obtained masterbatch is put into a blown film machine and blown at 170°C to obtain a UV-resistant degradable film for seed corn.

[0022] Example 5 (1) Under nitrogen protection, 3.04 g of o-fluorobenzophenone, 3.95 g of 9,10-dihydro-9,9-dimethylacridine and 1.23 g of sodium hydride were added to 98 mL of tetrahydrofuran solvent. The mixture was stirred until homogeneous and reacted at 72 °C for 25 h. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, the mixture was washed and dried, and separated by column chromatography to obtain intermediate 1. (2) Add 0.87 g of intermediate 1 to 75 mL of chloroform solvent, stir and mix, and slowly add 0.76 g of N-bromosuccinimide at 3 °C. Then, move the reaction system to room temperature and react in the dark for 13 h. After the reaction is completed, evaporate the solvent, filter and obtain intermediate 2. (3) Add 0.45 g of intermediate 2 and 0.56 g of N,N-dimethylhexadecanine to 19 mL of N,N-dimethylformamide solvent, stir and mix, and reflux at 75 °C for 24 h. After the reaction is completed, recrystallize and dry to obtain modified benzophenone. (4) Add 0.61 g of 4-hydroxybenzophenone and 0.34 g of 3,3-dithiodipropionic acid to 55 mL of pyridine solvent, stir evenly, then add 0.02 g of p-toluenesulfonic acid and 0.03 g of dicyclohexylcarbodiimide, and react at 45 °C for 8 h. After the reaction is completed, remove the solvent by rotary evaporation, wash and dry to obtain the ultraviolet absorber. (5) 78 parts by weight of poly(butylene adipate / terephthalate), 11 parts by weight of polylactic acid, 7 parts by weight of barrier masterbatch, 2 parts by weight of modified benzophenone, 3 parts by weight of ultraviolet absorber, 0.5 parts by weight of antioxidant 1010 and 0.4 parts by weight of stearic acid are put into a high-speed mixer and mixed at 2800 rpm for 35 min to obtain a preliminary mixture. The obtained preliminary mixture is added to a twin-screw extruder and extruded at 155°C to granulate. Then the obtained masterbatch is put into a blown film machine and blown at 180°C to obtain a UV-resistant degradable film for seed corn.

[0023] Comparative Example 1 The difference between this comparative example and Example 5 is that intermediate 1 is used instead of modified benzophenone.

[0024] Comparative Example 2 The difference between this comparative example and Example 5 is that intermediate 2 is used instead of modified benzophenone.

[0025] Comparative Example 3 The difference between this comparative example and Example 5 is that 4-hydroxybenzophenone is used instead of the ultraviolet absorber.

[0026] Performance testing: The degradation films obtained in Examples 1-5 and Comparative Examples 1-3 were made into samples and their performance was tested.

[0027] (1) UV resistance test: UV aging test was conducted on each group of samples according to GB / T 16422.3-2014 for 360 hours to obtain the samples after UV aging. Then, using GB / T 528 as the reference standard, the tensile properties of each group of samples before and after UV aging were tested at a tensile rate of 90 mm / min. The test results are shown in Table 1.

[0028] Table 1: UV Resistance Performance Test

[0029] As can be seen from Table 1, the degradation film samples prepared in Examples 1-5 have better UV resistance.

[0030] (2) Antibacterial performance test: Referring to standard QB / T 2591-2003 "Test methods and antibacterial effects of antibacterial plastics", Escherichia coli (ATCC8099) and Staphylococcus aureus (ATCC6538) were inoculated into the degradable films prepared in Examples 1-5 and Comparative Examples 1-3, covered with polyethylene film, and cultured at (37±1)℃ and relative humidity >90% for 24h. The antibacterial rate was calculated based on the actual number of viable bacteria recovered. The test results are shown in Table 2.

[0031] Table 2: Antibacterial Performance Test

[0032] As can be seen from Table 2, the degradation membrane samples prepared in Examples 1-5 have better antibacterial properties.

[0033] The comparison shows that the tensile strength of the degradation film sample prepared in Comparative Example 1 after UV aging is significantly lower than that of the sample in the Example, and its antibacterial rate is also much lower. This is because the sample prepared in Comparative Example 1 lacks quaternary ammonium salt groups and long carbon chains compared to the sample in the Example, which leads to decreased material compatibility and poor structural stability, resulting in a decrease in both tensile strength and antibacterial rate. The degradation film sample prepared in Comparative Example 2 also shows a significant decrease in tensile strength and antibacterial rate after UV aging, but the tensile strength is slightly higher than that of Comparative Example 1, and the antibacterial rate is also significantly improved. This is because the sample prepared in Comparative Example 2 introduces bromine atoms compared to Comparative Example 1. Although bromine atoms have little effect on ultraviolet absorption, they can chemically bond to the polymer molecular chain, improving the durability and stability of intermediate 1. Furthermore, bromine atoms can accelerate the transition rate of molecules from singlet to triplet states, thus transferring energy to oxygen more quickly and increasing the quantum yield of singlet oxygen, thereby enhancing the antibacterial effect. The degradation film sample prepared in Comparative Example 3 showed the greatest decrease in tensile strength after ultraviolet aging, while its antibacterial rate remained almost unchanged. This is because the sample prepared in Comparative Example 3, compared to the sample in the example, only lacked ester and disulfide bonds, leading to a decrease in the UV resistance and weather resistance of the degradation film, while the antibacterial rate remained unaffected.

[0034] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0036] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A kind of anti-UV degradation film for seed corn, it is characterized by, It includes the following components by weight: 70-80 parts by weight of poly(butylene adipate / terephthalate), 8-12 parts by weight of polylactic acid, 5-7 parts by weight of barrier masterbatch, 1-3 parts by weight of modified benzophenone, 2-4 parts by weight of ultraviolet absorber, 0.3-0.5 parts by weight of antioxidant 1010, and 0.2-0.4 parts by weight of stearic acid; The method for preparing the modified benzophenone is as follows: Step 1: o-Fluorobenzophenone reacts with 9,10-dihydro-9,9-dimethylacridine to give intermediate 1; Step 2: Intermediate 1 reacts with N-bromosuccinimide to obtain intermediate 2; Step 3: Intermediate 2 reacts with N,N-dimethylhexadecanine to obtain modified benzophenone; The method for preparing the ultraviolet absorber is as follows: 4-Hydroxybenzophenone reacts with 3,3-dithiodipropionic acid to yield an ultraviolet absorber.

2. The UV-degradation preventing film for seed corn according to claim 1, characterized by, The method for preparing the modified benzophenone is as follows: Step 1: Under nitrogen protection, o-fluorobenzophenone, 9,10-dihydro-9,9-dimethylacridine, and sodium hydride were added to tetrahydrofuran solvent and stirred until homogeneous. The mixture was reacted at 65-75℃ for 22-26 hours. After the reaction was completed, the mixture was cooled to room temperature, the solvent was removed by rotary evaporation, and the mixture was washed and dried. The residue was separated by column chromatography to obtain intermediate 1. Step 2: Add intermediate 1 to chloroform solvent, stir and mix, slowly add N-bromosuccinimide dropwise at 0-5℃, then move the reaction system to room temperature and react in the dark for 10-14 hours. After the reaction is completed, evaporate the solvent, filter and obtain intermediate 2. Step 3: Add intermediate 2 and N,N-dimethylhexadecanine to N,N-dimethylformamide solvent, stir and mix, and reflux at 60-80℃ for 20-25 h. After the reaction is completed, recrystallize and dry to obtain modified benzophenone.

3. The UV-degradation preventing film for seed corn according to claim 2, characterized by, In step one, the ratio of tetrahydrofuran, o-fluorobenzophenone, 9,10-dihydro-9,9-dimethylacridine, and sodium hydride is 90-100mL:3-3.05g:3.92-3.96g:1.2-1.24g.

4. The UV-degradation preventing film for seed corn according to claim 2, characterized by, In step two, the ratio of chloroform, intermediate 1, and N-bromosuccinimide is 60-80 mL: 0.84-0.88 g: 0.74-0.76 g.

5. The UV-degradation preventing film for seed corn according to claim 2, characterized by, In step three, the ratio of N,N-dimethylformamide, intermediate 2, and N,N-dimethylhexadecylamine is 15-20 mL: 0.42-0.46 g: 0.53-0.57 g.

6. The UV-degradation preventing film for seed corn according to claim 1, characterized by, The method for preparing the ultraviolet absorber is as follows: 4-hydroxybenzophenone and 3,3-dithiodipropionic acid are added to a pyridine solvent and stirred until homogeneous. Then, p-toluenesulfonic acid and dicyclohexylcarbodiimide are added to the solvent and the mixture is reacted at 30-50°C for 6-8 hours. After the reaction is completed, the solvent is removed by rotary evaporation, and the mixture is washed and dried to obtain the ultraviolet absorber.

7. The UV-degradation preventing film for seed corn according to claim 6, characterized by, The ratio of pyridine, 4-hydroxybenzophenone, 3,3-dithiodipropionic acid, p-toluenesulfonic acid, and dicyclohexylcarbodiimide is 40-60 mL: 0.58-0.62 g: 0.31-0.35 g: 0.01-0.02 g: 0.01-0.03 g.

8. A method for preparing the ultraviolet degradation resistant film for seed corn according to any one of claims 1 to 7, characterized by, The preparation method of the anti-ultraviolet degradation film for seed corn is as follows: polybutylene adipate terephthalate, polylactic acid, barrier master batch, modified benzophenone, ultraviolet absorber, antioxidant 1010 and stearic acid are put into a high-speed mixer, mixed at 2000-3000 rpm for 20-40 min to obtain primary mixture, the obtained primary mixture is added into a double screw extruder, extruded at 140-160 DEG C, granulated, and then the obtained master batch is put into a film blowing machine, and the film is formed by film blowing at 160-190 DEG C to obtain the anti-ultraviolet degradation film for seed corn.

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