Preparation method of fully biodegradable polylactic acid composite insect trapping plate

Abstract

The invention relates to a preparation method of a fully biodegradable polylactic acid composite insect trapping plate, and belongs to the technical field of insect trapping plates. The prepared polylactic acid composite insect trapping plate comprises the insect trapping plate base plate, the insect sticking glue layer and the release paper on the outermost layer, the prepared insect trapping plate can be completely degraded in nature by using a degradable material and is green and environmentally friendly, and modified cellulose, corn starch and other auxiliaries are added, so that the insect trapping plate has the advantages of environmental protection, environmental protection and the like. The durability of the composite insect trapping plate can be improved by improving the mechanical property and hydrophobicity of the material.

Description

Technical Field

[0001] The invention belongs to the technical field of insect attractant boards and relates to a method for preparing a fully biodegradable polylactic acid composite insect attractant board. Background Art

[0002] As a large agricultural country, pest control is a key step in agricultural planting. Due to the large amount of pesticides used in the pest control process, the residual chemicals not only pollute the environment, but also endanger our health. As people pay more attention to dietary health and environmental protection issues, the planting industry now begins to use insect traps in large quantities in the fields for pest control. It is an important means to improve ecological balance and achieve green and sustainable development of agricultural products. It has been widely used in the production of vegetables, flowers, forestry and fruit for pest monitoring and prevention. The use of insect traps effectively reduces the use of chemical pesticides, delays the development of pest resistance, reduces pesticide residues, and helps fruit and vegetable products meet green and pollution-free requirements.

[0003] At present, the base materials used in insect attracting boards are mostly PP or PVC from the petrochemical industry. After being discarded, they are not easy to degrade, causing secondary pollution to the agricultural ecological environment. Therefore, in order to meet the concept of green environmental protection, insect attracting boards need to be non-toxic, harmless, and naturally degradable; at the same time, in order to improve the durability of insect attracting board materials, they also need to have certain mechanical properties. Summary of the invention

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

[0005] The purpose of the present invention can be achieved through the following technical solutions:

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

[0007] S1. Mix 70 to 85 parts of polylactic acid, 40 to 55 parts of polybutylene succinate, 20 to 30 parts of modified cellulose, 20 to 30 parts of corn starch, 3 to 5 parts of a cross-linking agent, 5 to 10 parts of a plasticizer, 5 to 10 parts of a biodegradable color powder and 4 to 7 parts of a lubricant at 60 to 100° C., and stir at a speed of 300 to 500 rpm for 2 to 3.5 hours to obtain a mixture A.

[0008] S2, adding mixed material A to the silo of a twin-screw extruder, and preparing a substrate masterbatch by extrusion granulation, wherein the temperature of the die head in the twin-screw extruder is 140-220° C., the extrusion temperature is 140-220° C., and the speed of the twin-screw extruder is 160-300 rpm;

[0009] S3, adding the substrate masterbatch into a sheet extruder, and obtaining the insect attractant board substrate after extrusion molding and cutting;

[0010] S4, passing the insect attractant board substrate into a steam heat treatment at a temperature of 200-250° C. for 1-2.5 hours, cooling it naturally to room temperature, and then blowing it with nitrogen at a flow rate of 10 m / s for 3-5 hours, and finally passing ozone at a flow rate of 15-18 m / s for sterilization for 1.5-2.5 hours to obtain a pretreated insect attractant board substrate;

[0011] S5, spraying insect glue on both sides of the pretreated insect attractant substrate to form an insect glue layer, and then covering the insect glue layer with release paper to obtain the biodegradable polylactic acid composite insect attractant.

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

[0013] Add chitosan to pyridine, heat to 100-105°C, stir evenly, then add stearoyl chloride, continue stirring for 3-5h, cool to room temperature, wash with ethanol, centrifuge, completely dissolve the collected sediment with tetrahydrofuran, purify with ethanol, and vacuum dry to obtain modified chitosan, wherein the mass ratio of chitosan, stearoyl chloride, and pyridine is 1:(3-4):(30-35);

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

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

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

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

[0018] As a preferred technical solution 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 technical solution of the present invention, in step S3, the extrusion temperature of the sheet extruder is 100-220°C.

[0020] As a preferred technical solution of the present invention, in step S4, the coating amount of the insect glue is 50-100 g / m 2 .

[0021] As a preferred technical solution of the present invention, in step S4, during the steam heat treatment, the amount of water vapor introduced is 1.5-2 kg / h.

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

[0023] According to the mass proportion, the cellulose is ball-milled at a speed of 400 r / min for 0.5 h in a ball mill, and then 5 to 10 parts of the ball-milled cellulose are stirred in an ethanol solution of 50 to 65 parts of menthol and sodium laurate at 20 to 35° C. and 0.5 to 2 MPa for 7 to 12 h, wherein the mass ratio of menthol, sodium laurate and ethanol is 1:3:40. Finally, the pH value of the mixed solution is adjusted to 7 to 9, and the hydrophobically treated cellulose is obtained after drying.

[0024] In the present invention, the hydroxyl groups in chitosan are replaced by the carboxyl groups of stearoyl chloride to prepare modified chitosan. The lipophilicity and long-chain alkyl groups of fatty acid esters are introduced into the original chitosan structure, so that the modified chitosan has higher hydrophobicity.

[0025] In the present invention, the cellulose is firstly subjected to ball milling treatment to increase the particle size and size uniformity of the cellulose, increase the surface area and active sites of the cellulose, and then the hydrophobicity is enhanced by stirring and drying in a mixed solution of menthol and sodium laurate. Both menthol and sodium laurate can be dissolved in ethanol. After blending, the hydrophobicity of the solution can be further enhanced. At the same time, the addition of menthol to the solution can improve the stability of the solution, reduce the surface tension of the solution, and improve the fluidity of the solution. Sodium laurate can form a hydrophobic layer with the surface of cellulose with more surface active sites through physical adsorption. In addition to the hydrophobicity of menthol itself, it also has a lubricating effect, which can make the cellulose smoother after treatment, so that the treated cellulose has stronger hydrophobicity.

[0026] Under alkaline conditions, modified chitosan is mixed with pretreated cellulose, wherein the modified chitosan can be used as a continuous phase to fill cellulose and can form a strong hydrogen bond force with cellulose, thereby enhancing the mechanical properties of the modified cellulose; at the same time, epichlorohydrin is added to the mixed system as a cross-linking agent, which can make the unreacted hydroxyl groups in the chitosan molecular chain cross-linked to form a spatial network structure, thereby improving the structural stability and mechanical strength of the modified chitosan, and can be entangled with cellulose to form a more stable structure. Through these two aspects, the tensile strength of the modified cellulose is jointly improved.

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

[0028] Beneficial effects of the present invention:

[0029] (1) The biodegradable polylactic acid composite insect attractant prepared by the present invention comprises an insect attractant substrate and an insect glue layer formed by insect glue sprayed on the surface of the substrate. The insect attractant substrate material mainly comprises polylactic acid, polybutylene succinate, modified cellulose and corn starch. Polylactic acid has good biodegradability. After adding polybutylene succinate, its higher 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 the cellulose, and the corn starch plays the role of a reinforcing phase in the polymer matrix. Under the joint action of the additives, a biodegradable polylactic acid composite insect attractant is prepared.

[0030] (2) The polylactic acid composite insect attractant board prepared by the present invention can be completely degraded in nature, is green and environmentally friendly, and can improve the durability of the insect attractant board by improving the mechanical properties and hydrophobicity of the material. DETAILED DESCRIPTION

[0031] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0032] The insect glue used in the present invention is a biodegradable insect glue on the market. The insect glue used in the following examples and comparative examples is purchased from Shenzhen Taiqiang Investment Holding Co., Ltd.

[0033] Biodegradable color powder: all purchased from Chengdu Chuanlu Plastic 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 Materials 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 Myril 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 Jixinyibang Biotechnology Co., Ltd., product number: jxyb0301;

[0043] Glycerol: 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 Biopharmaceutical Technology Co., Ltd.;

[0050] Sodium 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, and stearoyl chloride was added after stirring evenly. The mixture was stirred for 3 hours, cooled to room temperature, washed with ethanol, and centrifuged. The collected sediment was completely dissolved with tetrahydrofuran and then purified with ethanol. The modified chitosan was obtained after vacuum drying, wherein the mass ratio of chitosan, stearoyl chloride, and pyridine was 1:3:30.

[0054] According to the mass fraction, the cellulose was ball-milled at a speed of 400 r / min for 0.5 h, and then 5 parts of the ball-milled cellulose were stirred in 50 parts of an ethanol solution of menthol and sodium laurate at 20°C and 0.5 MPa for 7 h, wherein the mass ratio of menthol, sodium laurate and ethanol was 1:3:40, and finally the pH of the mixed solution was adjusted to 7, and the pretreated cellulose was obtained after drying;

[0055] According to the mass proportion, 10 parts of modified chitosan were mixed with 70 parts of tetrahydrofuran and stirred for 30 minutes, 3 parts of epichlorohydrin were added and stirred for 1 hour, and 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. The modified cellulose was obtained by filtering, washing, drying, crushing, and passing through a 200-mesh sieve.

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

[0057] S2, adding mixed material A into the silo of a twin-screw extruder, and preparing substrate masterbatch by extrusion granulation, wherein the temperature of the die head in the twin-screw extruder is 140° C., the extrusion temperature is 140° C., and the speed of the twin-screw extruder is 160 rpm;

[0058] S3, adding the substrate masterbatch into a sheet extruder, extruding and molding at an extrusion temperature of 100° C. and cutting to obtain an insect attractant board substrate;

[0059] S4, passing water vapor at a temperature of 200°C to heat the insect attractant board substrate for 1 hour, cooling it naturally to room temperature, and then purging it with nitrogen at a flow rate of 10m / s for 3 hours, and finally passing ozone at a flow rate of 15m / s for sterilization for 1.5 hours to obtain a pretreated insect attractant board substrate, wherein the amount of water vapor passed is 1.5kg / h;

[0060] S5, spraying insect glue on both sides of the pre-treated insect trap substrate to form an insect glue layer, wherein the coating amount of the insect glue is 50g / m 2 , and then the release paper is covered on the outside of the insect glue layer to prepare 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, and stearoyl chloride was added after stirring evenly, and 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 with tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained, wherein the mass ratio of chitosan, stearoyl chloride and pyridine was 1:3.5:33.

[0064] According to the mass fraction, the cellulose was ball-milled at a speed of 400 r / min for 0.5 h, and then 8 parts of the ball-milled cellulose were stirred in 58 parts of an ethanol solution of menthol and sodium laurate at 28°C and 1 MPa for 10 h, wherein the mass ratio of menthol, sodium laurate and ethanol was 1:3:40, and finally the pH of the mixed solution was adjusted to 8, and the pretreated cellulose was obtained after drying;

[0065] 12 parts of modified chitosan were mixed with 75 parts of tetrahydrofuran and stirred for 35 minutes, 4 parts of epichlorohydrin were added and stirred for 1.5 hours, 0.4 parts of sodium hydroxide were added and stirred for 3.5 hours, and 30 parts of pretreated cellulose were added and stirred for 3.5 hours. The cellulose was filtered, washed, dried, crushed, and passed through a 200-mesh sieve to obtain modified cellulose.

[0066] S1. Mix 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 at 80° C., and stir at 400 rpm for 2.5 hours to obtain a mixture A.

[0067] S2, adding mixed material A to the silo of a twin-screw extruder, and preparing substrate masterbatch by extrusion granulation, wherein the temperature of the die head in the twin-screw extruder is 180° C., the extrusion temperature is 180° C., and the speed of the twin-screw extruder is 220 rpm;

[0068] S3, adding the substrate masterbatch into a sheet extruder, extruding and forming at an extrusion temperature of 180° C. and cutting to obtain an insect attractant board substrate;

[0069] S4, passing water vapor at a temperature of 220°C to heat the insect trap substrate for 1.5 hours, cooling it naturally to room temperature, and then purging it with nitrogen at a flow rate of 10m / s for 4 hours, and finally passing ozone at a flow rate of 17m / s for sterilization for 2 hours to obtain a pretreated insect trap substrate, wherein the amount of water vapor passed is 1.8kg / h;

[0070] S5, spraying insect glue on both sides of the pre-treated insect trap substrate to form an insect glue layer, wherein the coating amount of the insect glue is 80g / m 2 , and then the release paper is covered on the outside of the insect glue layer to prepare 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, and then stearoyl chloride was added after stirring evenly, and the 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 with tetrahydrofuran and then purified with ethanol. After vacuum drying, modified chitosan was obtained, wherein the mass ratio of chitosan, stearoyl chloride and pyridine was 1:4:35.

[0074] According to the mass fraction, the cellulose was ball-milled at a speed of 400 r / min for 0.5 h, and then 10 parts of the ball-milled cellulose were stirred in 65 parts of an ethanol solution of menthol and sodium laurate at 35°C and 2 MPa for 12 h, wherein the mass ratio of menthol, sodium laurate and ethanol was 1:3:40, and finally the pH of the mixed solution was adjusted to 9, and the pretreated cellulose was obtained after drying;

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

[0076] S1. In parts by mass, 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 were mixed, and stirred at a speed of 500 rpm for 3.5 hours to obtain a mixture A;

[0077] S2, adding mixed material A to the silo of a twin-screw extruder, and preparing a substrate masterbatch by extrusion granulation, wherein the temperature of the die head in the twin-screw extruder is 220° C., the extrusion temperature is 220° C., and the speed of the twin-screw extruder is 300 rpm;

[0078] S3, adding the substrate masterbatch into a sheet extruder, extruding and molding at an extrusion temperature of 220° C. and cutting to obtain an insect attractant board substrate;

[0079] S4, passing water vapor at a temperature of 250°C to heat the insect attractant board substrate for 2.5 hours, cooling it naturally to room temperature, and then purging it with nitrogen at a flow rate of 10m / s for 5 hours, and finally passing ozone at a flow rate of 18m / s for sterilization for 2.5 hours to obtain a pretreated insect attractant board substrate, wherein the amount of water vapor passed is 2kg / h;

[0080] S5, spraying insect glue on both sides of the pre-treated insect attractant substrate to form an insect glue layer, wherein the coating amount of the insect glue is 100g / m 2 , and then the release paper is covered on the outside of the insect glue layer to prepare a biodegradable polylactic acid composite insect attractant board.

[0081] Comparative Example 1

[0082] The difference between Comparative Example 1 and Example 1 is that modified chitosan is not added during the preparation of modified cellulose in Comparative Example 1, and the other operations are the same.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 1 is that in the preparation process of the modified cellulose in Comparative Example 2, epichlorohydrin was not added for treatment, and 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 is not subjected to any modification treatment, and the other operations are the same.

[0087] Comparative Example 4

[0088] The difference between Comparative Example 4 and Example 1 is that in the preparation process of the modified cellulose in Comparative Example 4, the cellulose is not pretreated, and the other operations are 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 has not been subjected to any modification treatment, and the other operations are the same.

[0091] Performance Test:

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

[0093] 2. Use OCA20 optical contact angle meter to test the water contact angle on the surface of the plate, the water droplet is 5μL, and the test is repeated 3 times to take the average value;

[0094] The results are as follows:

[0095]

[0096] According to the above data, the data of the embodiments are better than those of the comparative examples, indicating that the insect attractant plate prepared by the method of the present invention has excellent mechanical properties and hydrophobicity.

[0097] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a biodegradable polylactic acid composite insect attractant board, characterized in that: The method comprises the following preparation steps: S1. Mix 70 to 85 parts of polylactic acid, 40 to 55 parts of polybutylene succinate, 20 to 30 parts of modified cellulose, 20 to 30 parts of corn starch, 3 to 5 parts of a cross-linking agent, 5 to 10 parts of a plasticizer, 5 to 10 parts of a biodegradable color powder and 4 to 7 parts of a lubricant at 60 to 100° C., and stir at a speed of 300 to 500 rpm for 2 to 3.5 hours to obtain a mixture A. S2, adding mixed material A to the silo of a twin-screw extruder, and preparing a substrate masterbatch by extrusion granulation, wherein the temperature of the die head in the twin-screw extruder is 140-220° C., the extrusion temperature is 140-220° C., and the speed of the twin-screw extruder is 160-300 rpm; S3, adding the substrate masterbatch into a sheet extruder, and obtaining the insect attractant board substrate after extrusion molding and cutting; S4, passing the insect attractant board substrate into a steam heat treatment at a temperature of 200-250° C. for 1-2.5 hours, cooling it naturally to room temperature, and then blowing it with nitrogen at a flow rate of 10 m / s for 3-5 hours, and finally passing ozone at a flow rate of 15-18 m / s for sterilization for 1.5-2.5 hours to obtain a pretreated insect attractant board substrate; S5, spraying insect glue on both sides of the pretreated insect attractant board substrate to form an insect glue layer, and then covering the insect glue layer with release paper to obtain the biodegradable polylactic acid composite insect attractant board.

2. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that: In step S1, the preparation process of the modified cellulose is as follows: Add chitosan to pyridine, heat to 100-105°C, stir evenly, then add stearoyl chloride, continue stirring for 3-5h, cool to room temperature, wash with ethanol, centrifuge, completely dissolve the collected sediment with tetrahydrofuran, purify with ethanol, and vacuum dry to obtain modified chitosan, wherein the mass ratio of chitosan, stearoyl chloride, and pyridine is 1:(3-4):(30-35); According to the mass proportion, 10-15 parts of modified chitosan and 70-80 parts of tetrahydrofuran are mixed and stirred for 30-40 minutes, 3-5 parts of epichlorohydrin are added and stirred for 1-2 hours, and then 0.3-0.5 parts of sodium hydroxide are added and stirred for 3-4 hours, and then 20-30 parts of pretreated cellulose are added and stirred for 3-4 hours. The modified cellulose is obtained by filtering, washing, drying, crushing, and passing through a 200-mesh sieve.

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

4. 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.

5. 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.

6. 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.

7. 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°C.

8. The method for preparing the biodegradable polylactic acid composite insect attractant according to claim 1, characterized in that: In step S4, the coating amount of the insect glue is 50-100 g / m 2 .

9. 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 amount of water vapor introduced is 1.5-2 kg / h.

10. The method for preparing the biodegradable polylactic acid composite insect attractant board according to claim 2, characterized in that: The preparation process of the pretreated cellulose is as follows: According to the mass proportion, the cellulose is ball-milled at a speed of 400 r / min for 0.5 h in a ball mill, and then 5 to 10 parts of the ball-milled cellulose are stirred in an ethanol solution of 50 to 65 parts of menthol and sodium laurate at 20 to 35° C. and 0.5 to 2 MPa for 7 to 12 h, wherein the mass ratio of menthol, sodium laurate and ethanol is 1:3:

40. Finally, the pH value of the mixed solution is adjusted to 7 to 9, and the pretreated cellulose is obtained after drying.

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