Preparation method of a biodegradable polylactic acid composite moth board

Abstract

The present application relates to a kind of preparation methods of biological full-degradable polylactic acid composite moth board, belong to moth board technical field.The polylactic acid composite moth board prepared by the present application includes moth board substrate, moth glue layer and the outermost release paper, by using degradable material to reach the prepared moth board can be completely degraded in nature, green environmental protection, and modified cellulose and corn starch and other additives are added, the durability of composite moth board can be improved by improving the mechanical properties and hydrophobicity of material.

Description

Technical Field

[0001] This invention belongs to the field of insect trap technology and relates to a method for preparing a biodegradable polylactic acid composite insect trap. Background Technology

[0002] As a major agricultural country, pest control is a crucial step in agricultural planting. The extensive use of pesticides in pest control not only pollutes the environment but also harms our health. With increasing emphasis on dietary health and environmental protection, the use of insect-attracting boards in fields is now widespread. This is an important means of improving ecological balance and achieving green and sustainable agricultural development, and it is widely used in vegetable, flower, and fruit production for pest monitoring and control. The use of insect-attracting boards effectively reduces the amount of chemical pesticides used, delays the development of pesticide resistance in pests, reduces pesticide residues, and helps fruit and vegetable products meet green and pollution-free requirements.

[0003] Currently, the base materials used in insect-attracting boards are mostly PP or PVC from the petrochemical industry. These materials are difficult to degrade after disposal, causing secondary pollution to the agricultural environment. Therefore, to meet the concept of green environmental protection, insect-attracting boards need to be non-toxic, harmless, and biodegradable; at the same time, to improve the durability of the insect-attracting board materials, they also need to possess certain mechanical properties. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a biodegradable polylactic acid composite insect attractant. The insect attractant prepared by this invention not only uses biodegradable materials, but also has excellent mechanical properties and hydrophobicity.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for preparing a biodegradable polylactic acid composite insect attractant includes the following preparation steps:

[0007] S1. By weight, 70-85 parts of polylactic acid, 40-55 parts of polybutylene succinate, 20-30 parts of modified cellulose, 20-30 parts of corn starch, 3-5 parts of crosslinking agent, 5-10 parts of plasticizer, 5-10 parts of biodegradable color powder and 4-7 parts of lubricant are mixed at 60-100℃ and stirred at 300-500 rpm for 2-3.5 hours to obtain mixture A;

[0008] S2. Add mixture A to the hopper of a twin-screw extruder and prepare substrate masterbatch by extrusion granulation. The temperature of the die head in the twin-screw extruder is 140-220℃, the extrusion temperature is 140-220℃, and the rotation speed of the twin-screw extruder is 160-300 rpm.

[0009] S3. Add the substrate masterbatch into the sheet extruder, and after extrusion molding and slitting, obtain the insect-attracting board substrate;

[0010] S4. Heat the insect-attracting board substrate with steam at a temperature of 200-250℃ for 1-2.5 hours, let it cool naturally to room temperature, then purge it with nitrogen gas at a flow rate of 10 m / s for 3-5 hours, and finally sterilize it with ozone gas at a flow rate of 15-18 m / s for 1.5-2.5 hours to obtain the pretreated insect-attracting board substrate.

[0011] S5. Spray insect-sticking glue on both sides of the pretreated insect-attracting board substrate to form an insect-sticking glue layer, and then cover the insect-sticking glue layer with release paper to obtain the biodegradable polylactic acid composite insect-attracting board.

[0012] As a preferred embodiment of the present invention, the preparation process of the modified cellulose in step S1 is as follows:

[0013] Chitosan was added to pyridine, heated to 100-105℃, stirred evenly, and then stearoyl chloride was added. Stirring was continued for 3-5 hours. After cooling to room temperature, the mixture was washed with ethanol and centrifuged. The collected sediment was completely dissolved in tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained. The mass ratio of chitosan, stearoyl chloride and pyridine was 1:(3-4):(30-35).

[0014] According to the mass fraction, 10-15 parts of modified chitosan and 70-80 parts of tetrahydrofuran are mixed and stirred for 30-40 minutes. Then, 3-5 parts of epichlorohydrin are added and stirred for 1-2 hours. Next, 0.3-0.5 parts of sodium hydroxide are added and stirred for 3-4 hours. Then, 20-30 parts of pretreated cellulose are added and stirred for 3-4 hours. After filtration, washing, drying, pulverizing, and passing through a 200-mesh sieve, modified cellulose is obtained.

[0015] As a preferred embodiment of the present invention, in step S1, the crosslinking agent is one or both of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and benzoyl peroxide.

[0016] As a preferred embodiment of the present invention, in step S1, the plasticizer is one of epoxidized soybean oil and glycerin.

[0017] As a preferred embodiment of the present invention, in step S1, the lubricant is one of calcium stearate, stearic acid, butyl stearate and oleamide.

[0018] As a preferred embodiment of the present invention, in step S1, the biodegradable color powder is one of biodegradable yellow powder and biodegradable blue powder.

[0019] As a preferred embodiment of the present invention, in step S3, the extrusion temperature of the sheet extruder is 100-220°C.

[0020] As a preferred embodiment of the present invention, in step S4, the coating amount of the insect-sticking adhesive is 50-100 g / m². 2 .

[0021] As a preferred embodiment of the present invention, in step S4, the steam flow rate during the steam heat treatment is 1.5 to 2 kg / h.

[0022] As a preferred embodiment of the present invention, the preparation process of the pretreated cellulose is as follows:

[0023] Cellulose was ball-milled at 400 r / min for 0.5 h according to mass fractions. Then, 5 to 10 parts of the ball-milled cellulose were stirred in an ethanol solution of 50 to 65 parts of menthol and sodium lauryl ester at 20 to 35 °C and 0.5 to 2 MPa for 7 to 12 h. The mass ratio of menthol, sodium lauryl ester and ethanol was 1:3:40. Finally, the pH of the mixed solution was adjusted to 7 to 9, and the solution was dried to obtain the hydrophobic treated cellulose.

[0024] In this invention, the hydroxyl groups in chitosan are replaced by the carboxyl groups of stearoyl chloride to prepare modified chitosan. Based on the original chitosan structure, the lipophilicity of fatty acid esters and long-chain alkyl groups are introduced, which makes the modified chitosan have high hydrophobicity.

[0025] In this invention, cellulose is first ball-milled to increase particle size and uniformity, as well as surface area and active sites. Then, it is stirred and dried in a mixed solution of menthol and sodium lauryl to enhance hydrophobicity. Both menthol and sodium lauryl are soluble in ethanol; their blending further enhances the hydrophobicity of the solution. Additionally, the addition of menthol improves solution stability, reduces surface tension, and increases fluidity. Sodium lauryl can physically adsorb onto the cellulose surface, which has numerous active sites, to form a hydrophobic layer. In addition to its inherent hydrophobicity, menthol also has a lubricating effect, making the cellulose smoother after treatment, resulting in even stronger hydrophobicity.

[0026] Under alkaline conditions, modified chitosan is mixed with pretreated cellulose. The modified chitosan acts as a continuous phase to fill cellulose and forms strong hydrogen bonds with cellulose, thereby enhancing the mechanical properties of the modified cellulose. At the same time, epichlorohydrin is added to the mixture as a crosslinking agent, which allows the unreacted hydroxyl groups in the chitosan molecular chain to crosslink and form a spatial network structure, thereby improving the structural stability and mechanical strength of the modified chitosan. It can also intertwine with cellulose to form a more stable structure. Through these two aspects, the tensile strength of the modified cellulose is improved.

[0027] After granulation and extrusion molding, the substrate of the insect-attracting board is heat-treated with water vapor to remove impurities and oil stains from the surface, and then the surface is purged with nitrogen to remove residual moisture. Finally, it is sterilized with ozone.

[0028] The beneficial effects of this invention are:

[0029] (1) The biodegradable polylactic acid composite insect attractant prepared by the present invention includes an insect attractant substrate and an insect sticky layer formed by spraying insect sticky glue on the surface of the substrate. The substrate material mainly includes polylactic acid, polybutylene succinate, modified cellulose and corn starch. Polylactic acid has good biodegradability. After adding polybutylene succinate, its high strength and toughness can be used to help improve the mechanical properties of polylactic acid, and enhance the durability and service life of the insect attractant material. At the same time, the tensile strength of the material is improved by modifying cellulose, and corn starch plays the role of a reinforcing phase in the polymer matrix. Under the combined action of the additives, the biodegradable polylactic acid composite insect attractant is prepared.

[0030] (2) The polylactic acid composite insect-attracting board prepared by the present invention can be completely degraded in nature, is green and environmentally friendly, and its durability can be improved by improving the mechanical properties and hydrophobicity of the material. Detailed Implementation

[0031] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0032] The sticky insect glue used in this invention is a commercially available biodegradable sticky insect glue. The sticky insect agents used in the following examples and comparative examples were purchased from Shenzhen Taiqiang Investment Holding Co., Ltd.

[0033] Biodegradable pigments: all purchased from Chengdu Chuanlv Plastics Co., Ltd.

[0034] Stearoyl chloride: purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: S817443;

[0035] Chitosan: Purchased from Xi'an Kangnuo Chemical Co., Ltd.;

[0036] Pyridine: Purchased from Shandong Minghua New Materials Co., Ltd.;

[0037] Cellulose: Purchased from Shandong Yilai New Material Technology Development Co., Ltd.

[0038] Epichlorohydrin: Purchased from Shandong Jinyueyuan New Materials Co., Ltd.;

[0039] Polylactic acid: purchased from Hubei Shishun Biotechnology Co., Ltd.;

[0040] Polybutylene succinate: purchased from Shanghai Mairui Biochemical Technology Co., Ltd.;

[0041] 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane: purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: T819468;

[0042] Epoxidized soybean oil: purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd., product number: jxyb0301;

[0043] Glycerin: Purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: G810585;

[0044] Stearic acid: purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: S796727;

[0045] Calcium stearate: purchased from Shanghai Maclean Biochemical Technology Co., Ltd.;

[0046] Benzoyl peroxide: Purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number: B104630;

[0047] Corn starch: purchased from Jiangsu Duoyang Bioengineering Technology Co., Ltd.;

[0048] γ-Mercaptopropyltrimethoxysilane: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number: M812736;

[0049] Menthol: Purchased from Shanghai Haohong Biomedical Technology Co., Ltd.;

[0050] Sodium lauryl laurate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number: S817491.

[0051] Example 1

[0052] Preparation of modified cellulose:

[0053] Chitosan was added to pyridine, heated to 100°C, stirred evenly, and then stearoyl chloride was added. Stirring was continued for 3 hours. After cooling to room temperature, the mixture was washed with ethanol and centrifuged. The collected sediment was completely dissolved in tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained. The mass ratio of chitosan, stearoyl chloride and pyridine was 1:3:30.

[0054] Cellulose was ball-milled at 400 r / min for 0.5 h according to mass fractions. Then, 5 parts of the ball-milled cellulose were stirred in an ethanol solution of 50 parts of menthol and sodium lauryl ester at 20℃ and 0.5 MPa for 7 h. The mass ratio of menthol, sodium lauryl ester and ethanol was 1:3:40. Finally, the pH of the mixed solution was adjusted to 7 and dried to obtain pretreated cellulose.

[0055] According to the mass fraction, 10 parts of modified chitosan and 70 parts of tetrahydrofuran were mixed and stirred for 30 minutes, 3 parts of epichlorohydrin were added and stirred for 1 hour, then 0.3 parts of sodium hydroxide were added and stirred for 3 hours, and then 20 parts of pretreated cellulose were added and stirred for 3 hours. After filtration, washing, drying, pulverizing, and passing through a 200-mesh sieve, modified cellulose was obtained.

[0056] S1. By mass, at 60°C, 70 parts polylactic acid, 40 parts polybutylene succinate, 20 parts modified cellulose, 20 parts corn starch, 3 parts 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 5 parts epoxidized soybean oil, 5 parts biodegradable yellow powder and 4 parts stearic acid are mixed and stirred at 300 rpm for 2 hours to obtain mixture A.

[0057] S2. Add mixture A to the hopper of a twin-screw extruder and prepare substrate masterbatch by extrusion granulation. The temperature of the die head in the twin-screw extruder is 140℃, the extrusion temperature is 140℃, and the rotation speed of the twin-screw extruder is 160rpm.

[0058] S3. Add the substrate masterbatch to the sheet extruder, extrude it at an extrusion temperature of 100°C, and then cut it to obtain the insect-attracting board substrate.

[0059] S4. The insect-attracting board substrate is heat-treated with water vapor at 200℃ for 1 hour, naturally cooled to room temperature, and then purged with nitrogen gas at a flow rate of 10m / s for 3 hours. Finally, ozone gas at a flow rate of 15m / s is introduced for sterilization for 1.5 hours to obtain the pretreated insect-attracting board substrate, wherein the amount of water vapor introduced is 1.5kg / h.

[0060] S5. Spray insect-adhesive adhesive onto both sides of the pretreated insect-attracting board substrate to form an insect-adhesive layer, wherein the coating amount of insect-adhesive adhesive is 50g / m². 2 Then, release paper is covered on the outside of the sticky insect adhesive layer to obtain a biodegradable polylactic acid composite insect attractant board.

[0061] Example 2

[0062] Preparation of modified cellulose:

[0063] Chitosan was added to pyridine, heated to 103°C, stirred until homogeneous, and then stearoyl chloride was added. Stirring was continued for 4 hours. After cooling to room temperature, the mixture was washed with ethanol and centrifuged. The collected sediment was completely dissolved in tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained. The mass ratio of chitosan, stearoyl chloride, and pyridine was 1:3.5:33.

[0064] Cellulose was ball-milled at 400 r / min for 0.5 h according to mass fractions. Then, 8 parts of the ball-milled cellulose were stirred in an ethanol solution of 58 parts of menthol and sodium lauryl for 10 h at 28 °C and 1 MPa. The mass ratio of menthol, sodium lauryl, and ethanol was 1:3:40. Finally, the pH of the mixed solution was adjusted to 8, and the solution was dried to obtain pretreated cellulose.

[0065] 12 parts of modified chitosan and 75 parts of tetrahydrofuran were mixed and stirred for 35 minutes. 4 parts of epichlorohydrin were added and stirred for 1.5 hours. Then 0.4 parts of sodium hydroxide were added and stirred for 3.5 hours. 30 parts of pretreated cellulose were added and stirred for 3.5 hours. After filtration, washing, drying, pulverizing, and passing through a 200-mesh sieve, modified cellulose was obtained.

[0066] S1. By mass, 77 parts of polylactic acid, 50 parts of polybutylene succinate, 25 parts of modified cellulose, 25 parts of corn starch, 4 parts of benzoyl peroxide, 7 parts of epoxidized soybean oil, 8 parts of biodegradable yellow powder and 6 parts of calcium stearate are mixed at 80°C and stirred at 400 rpm for 2.5 hours to obtain mixture A.

[0067] S2. Add mixture A to the hopper of a twin-screw extruder and prepare substrate masterbatch by extrusion granulation. The temperature of the die head in the twin-screw extruder is 180°C, the extrusion temperature is 180°C, and the rotation speed of the twin-screw extruder is 220 rpm.

[0068] S3. The substrate masterbatch is added to the sheet extruder, extruded and slit at an extrusion temperature of 180°C to obtain the insect-attracting board substrate.

[0069] S4. The insect-attracting board substrate is heat-treated with water vapor at 220℃ for 1.5h, naturally cooled to room temperature, and then purged with nitrogen at a flow rate of 10m / s for 4h. Finally, ozone at a flow rate of 17m / s is introduced for sterilization for 2h to obtain the pretreated insect-attracting board substrate, wherein the amount of water vapor introduced is 1.8kg / h.

[0070] S5. Spray insect-adhesive adhesive onto both sides of the pretreated insect-attracting board substrate to form an insect-adhesive layer, wherein the coating amount of insect-adhesive adhesive is 80g / m². 2 Then, release paper is covered on the outside of the sticky insect adhesive layer to obtain a biodegradable polylactic acid composite insect attractant board.

[0071] Example 3

[0072] Preparation of modified cellulose:

[0073] Chitosan was added to pyridine, heated to 105°C, stirred evenly, and then stearoyl chloride was added. Stirring was continued for 5 hours. After cooling to room temperature, the mixture was washed with ethanol and centrifuged. The collected sediment was completely dissolved in tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained. The mass ratio of chitosan, stearoyl chloride and pyridine was 1:4:35.

[0074] Cellulose was ball-milled at 400 r / min for 0.5 h according to mass fractions. Then, 10 parts of the ball-milled cellulose were stirred in an ethanol solution of 65 parts of menthol and sodium lauryl ester at 35℃ and 2 MPa for 12 h. The mass ratio of menthol, sodium lauryl ester and ethanol was 1:3:40. Finally, the pH of the mixed solution was adjusted to 9 and dried to obtain pretreated cellulose.

[0075] 15 parts of modified chitosan and 80 parts of tetrahydrofuran were mixed and stirred for 40 minutes. 5 parts of epichlorohydrin were added and stirred for 2 hours. Then 0.5 parts of sodium hydroxide were added and stirred for 4 hours. 30 parts of pretreated cellulose were added and stirred for 4 hours. After filtration, washing, drying, pulverizing, and passing through a 200-mesh sieve, modified cellulose was obtained.

[0076] S1. By weight, at 100°C, 85 parts of polylactic acid, 55 parts of polybutylene succinate, 30 parts of modified cellulose, 30 parts of corn starch, 5 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 10 parts of glycerol, 10 parts of biodegradable blue powder and 7 parts of calcium stearate are mixed and stirred at 500 rpm for 3.5 h to obtain mixture A.

[0077] S2. Add mixture A to the hopper of a twin-screw extruder and prepare substrate masterbatch by extrusion granulation. The temperature of the die head in the twin-screw extruder is 220°C, the extrusion temperature is 220°C, and the rotation speed of the twin-screw extruder is 300 rpm.

[0078] S3. The substrate masterbatch is added to the sheet extruder, extruded and shaped at an extrusion temperature of 220°C, and then cut to obtain the insect-attracting board substrate.

[0079] S4. The insect-attracting board substrate is heat-treated with water vapor at 250℃ for 2.5h, naturally cooled to room temperature, and then purged with nitrogen gas at a flow rate of 10m / s for 5h. Finally, ozone gas at a flow rate of 18m / s is introduced for sterilization treatment for 2.5h to obtain the pretreated insect-attracting board substrate, wherein the amount of water vapor introduced is 2kg / h.

[0080] S5. Spray insect-adhesive adhesive onto both sides of the pretreated insect-attracting board substrate to form an insect-adhesive layer, wherein the coating amount of insect-adhesive adhesive is 100g / m². 2 Then, release paper is covered on the outside of the sticky insect adhesive layer to obtain a biodegradable polylactic acid composite insect attractant board.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that no modified chitosan was added during the preparation of modified cellulose in Comparative Example 1, while the other operations were the same.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that epichlorohydrin was not added during the preparation of the modified cellulose in Comparative Example 2, while the other operations were the same.

[0085] Comparative Example 3

[0086] The difference between Comparative Example 3 and Example 1 is that the chitosan in Comparative Example 3 was not modified in any way, while the rest of the operations were the same.

[0087] Comparative Example 4

[0088] The difference between Comparative Example 4 and Example 1 is that in the preparation process of modified cellulose in Comparative Example 4, the cellulose was not pretreated, but the other operations were the same.

[0089] Comparative Example 5

[0090] The difference between Comparative Example 5 and Example 1 is that the cellulose used in Comparative Example 5 was not modified in any way, but all other operations were the same.

[0091] Performance testing:

[0092] 1. The mechanical properties of the insect-attracting board substrates prepared in the examples and comparative examples were tested using a universal electronic tensile testing machine (KY8000C type) according to the standard (GB / T 1040.2-2006);

[0093] 2. The water contact angle of the board surface was tested using an OCA20 optical contact angle meter. The water droplet was 5μL, and the average value was taken after 3 tests.

[0094] The results are shown in the table below:

[0095]

[0096] Based on the above data, it can be seen that the data of the embodiments are all better than those of the comparative examples, indicating that the insect-attracting board prepared by the method of the present invention has excellent mechanical properties and hydrophobicity.

[0097] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a biodegradable polylactic acid composite insect attractant, characterized in that, The preparation steps include the following: S1. By weight, 70-85 parts of polylactic acid, 40-55 parts of polybutylene succinate, 20-30 parts of modified cellulose, 20-30 parts of corn starch, 3-5 parts of crosslinking agent, 5-10 parts of plasticizer, 5-10 parts of biodegradable color powder and 4-7 parts of lubricant are mixed at 60-100℃ and stirred at 300-500 rpm for 2-3.5 hours to obtain mixture A; S2. Add mixture A to the hopper of a twin-screw extruder and prepare substrate masterbatch by extrusion granulation. The temperature of the die head in the twin-screw extruder is 140~220℃, the extrusion temperature is 140~220℃, and the rotation speed of the twin-screw extruder is 160~300rpm. S3. Add the substrate masterbatch into the sheet extruder, and after extrusion molding and slitting, obtain the insect-attracting board substrate; S4. Heat the insect-attracting board substrate with water vapor at a temperature of 200~250℃ for 1~2.5h, let it cool naturally to room temperature, then purge it with nitrogen gas at a flow rate of 10m / s for 3~5h, and finally sterilize it with ozone gas at a flow rate of 15~18m / s for 1.5~2.5h to obtain the pretreated insect-attracting board substrate. S5. Spray insect-sticking glue on both sides of the pretreated insect-attracting board substrate to form an insect-sticking glue layer, and then cover the insect-sticking glue layer with release paper to obtain the biodegradable polylactic acid composite insect-attracting board. In step S1, the preparation process of the modified cellulose is as follows: Cellulose was ball-milled at 400 r / min for 0.5 h according to mass fractions. Then, 5 to 10 parts of the ball-milled cellulose were stirred in an ethanol solution of 50 to 65 parts of menthol and sodium lauryl ester at 20 to 35 °C and 0.5 to 2 MPa for 7 to 12 h. The mass ratio of menthol, sodium lauryl ester and ethanol was 1:3:

40. Finally, the pH of the mixed solution was adjusted to 7 to 9 and dried to obtain pretreated cellulose. Chitosan was added to pyridine, heated to 100-105℃, stirred evenly, and then stearoyl chloride was added. Stirring was continued for 3-5 hours. After cooling to room temperature, the mixture was washed with ethanol and centrifuged. The collected precipitate was completely dissolved in tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained. The mass ratio of chitosan, stearoyl chloride, and pyridine was 1:(3-4):(30-35). According to the mass fraction, 10-15 parts of modified chitosan and 70-80 parts of tetrahydrofuran are mixed and stirred for 30-40 minutes. Then, 3-5 parts of epichlorohydrin are added and stirred for 1-2 hours. Next, 0.3-0.5 parts of sodium hydroxide are added and stirred for 3-4 hours. Then, 20-30 parts of pretreated cellulose are added and stirred for 3-4 hours. After filtration, washing, drying, pulverizing, and passing through a 200-mesh sieve, modified cellulose is obtained.

2. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S1, the crosslinking agent is one or both of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and benzoyl peroxide.

3. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S1, the plasticizer is one of epoxidized soybean oil and glycerin.

4. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S1, the lubricant is one of calcium stearate, stearic acid, butyl stearate, and oleamide.

5. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S1, the biodegradable color powder is one of biodegradable yellow powder and biodegradable blue powder.

6. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S3, the extrusion temperature of the sheet extruder is 100~220℃.

7. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S4, the application amount of the insect-sticking adhesive is 50~100g / m². 2 .

8. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that, In step S4, during the steam heat treatment, the steam flow rate is 1.5~2 kg / h.

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