High-barrier slow-release nitrogen fertilizer biodegradable mulching film material and preparation method thereof

Abstract

The invention relates to the technical field of agricultural film coating, provides a high-barrier slow-release nitrogen fertilizer biodegradable mulching film material and a preparation method thereof, and solves the problems of high process difficulty, large process adjustment amplitude and high degradation time control difficulty of an existing multi-layer composite liquid film forming process. The water vapor transmission coefficient of the high-barrier slow-release nitrogen fertilizer biodegradable mulching film material is 300 to 600g / m < 2 > * 24h; comprising the following raw materials: compatibilized nitrogen-rich intercalation modified coal-based kaolin and a composite bio-based material, the mass ratio of the compatibilization nitrogen-rich intercalation modified coal-based kaolin to the composite bio-based material is 1: (9-99); the composite bio-based material is a mixture of one or more of poly (butylene adipate-co-terephthalate), polylactic acid or polypropylene carbonate in any proportion.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural film coating, and particularly relates to a highly barrier and slow-release nitrogen fertilizer biodegradable plastic film material and a preparation method thereof. Background Art

[0002] Global climate change is intensifying. The growth environment of crops has changed greatly. To ensure yields, the use intensity of pesticides, fertilizers, etc. has increased. The use of these chemical substances has increased farm yields, but they pose a great threat to the environment and human health.

[0003] Plastic films have functions such as heat preservation, moisture retention, water conservation, and weed suppression. The large-scale promotion of plastic film technology has increased crop yields and expanded planting areas. However, the large-scale use of plastic films has aggravated the "white pollution" in rural areas. The residual films have damaged the soil structure, caused soil compaction, and reduced the arable area. As of 2022, the usage amount of agricultural films has reached 2.358 million tons. It is urgent to promote the use of biodegradable plastic films. However, biodegradable materials have poor barrier properties. Therefore, it is of great significance to develop a plastic film with high barrier and slow-release functions.

[0004] Chinese Patent Application No. 202410697757.4 discloses a degradable liquid fertilizer plastic film with slow-release function and a preparation method thereof, which uses starch to prepare slow-release granules and serves as the main material of the film. Chinese Patent Application No. 202410668899.8 discloses a pest control and weed control environment symbiotic composite fully biodegradable plastic film and a preparation method and application thereof, which uses the solid residues of crops as fillers, loads plant-derived pesticides, and uses PBAT as the main resin carrier of the plastic film to prepare a slow-release pest control and weed control film. Chinese Patent Application No. 202410864724.4 discloses a preparation method of a urea / fulvic acid double slow-release sawdust-based degradable plastic film, which uses humified sawdust as raw material, compounded with urea and other auxiliaries and sprayed on a glass plate to form a solid slow-release plastic film. The biodegradable plastic films prepared by the above methods use processes such as multi-layer compounding and liquid film formation to prepare biodegradable plastic films, which have problems such as high process complexity, large process adjustment range, and high difficulty in controlling degradation time. At the same time, easier-to-degrade raw materials are used as the main materials of the film, and the film covering time of the plastic film cannot meet the planting requirements. Summary of the Invention

[0005] Therefore, in view of the above problems, the present invention provides a highly barrier and slow-release nitrogen fertilizer biodegradable plastic film material and a preparation method thereof, which solve the problems of high process difficulty, large process adjustment range, and high difficulty in controlling degradation time of the existing multi-layer compounding and liquid film formation processes.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-barrier slow-release nitrogen fertilizer biodegradable film material, the water vapor transmission coefficient of the high-barrier slow-release nitrogen fertilizer biodegradable film material is 300-600 g / m 2 ·24h; It includes the following raw materials: compatibilized nitrogen-rich intercalated modified coal-based kaolin, composite bio-based material; the mass ratio of the compatibilized nitrogen-rich intercalated modified coal-based kaolin to the composite bio-based material is 1:9-99; the composite bio-based material is a mixture of one or several of polybutylene adipate / terephthalate, polylactic acid or polypropylene carbonate in any proportion;

[0008] Among them, the preparation process of the compatibilized nitrogen-rich intercalated modified coal-based kaolin is as follows:

[0009] I. Preparation of nitrogen-rich intercalated modified coal-based kaolin: Prepare a urea aqueous solution with a concentration of 60-80%, weigh coal-based kaolin according to the mass ratio of coal-based kaolin to urea aqueous solution of 1:1-20, add it to the urea aqueous solution, stir and mix evenly, and react under ultrasonic, stirring and constant temperature water bath conditions for 6-12 h. After the reaction, cool, filter, wash, and vacuum dry to obtain nitrogen-rich intercalated modified coal-based kaolin;

[0010] II. Preparation of compatibilized nitrogen-rich intercalated modified coal-based kaolin: Calcinate the nitrogen-rich intercalated modified coal-based kaolin obtained in step I at 100-180 °C for 0.5-1 h, cool after calcination, then mix evenly with an organic solvent, add bio-based epoxy soybean oil and a catalyst to react, cool, filter, wash, and vacuum dry to obtain compatibilized nitrogen-rich intercalated modified coal-based kaolin.

[0011] Further, the temperature of the constant temperature water bath is 50-80 °C.

[0012] Further, the organic solvent is any one of dichloromethane, chloroform, trichloroethane, N,N-dimethylformamide or N,N-dimethylacetamide.

[0013] Further, the catalyst is any one of triphenylphosphine, triethylamine or benzyltriethylammonium chloride.

[0014] Further, the mass ratio of the catalyst to the bio-based epoxy soybean oil is 1:3-9, and the mass ratio of the bio-based epoxy soybean oil to the nitrogen-rich intercalated modified coal-based kaolin is 3-10:1

[0015] Further, it includes the following steps: Mix the compatibilized nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based material evenly, carry out mixing and granulation, water cooling, and pelletizing with a twin-screw extruder, and then blow it out with a blown film machine to obtain the high-barrier slow-release nitrogen fertilizer biodegradable film material.

[0016] Further, the temperatures of the seven zones of the twin-screw extruder are: 120 - 135 °C, 120 - 145 °C, 140 - 150 °C, 140 - 155 °C, 140 - 155 °C, 140 - 160 °C, 140 - 160 °C, and the rotation speed is 200 - 270 rpm.

[0017] Further, the temperatures of the four zones of the blown film machine are: 130 - 145 °C, 130 - 150 °C, 130 - 150 °C, 130 - 150 °C, and the rotation speed is 35 - 50 rpm.

[0018] By adopting the foregoing technical solutions, the beneficial effects of the present invention are as follows:

[0019] 1. Coal-based kaolin has a lamellar structure microscopically. Uniformly dispersed in the polymer matrix, it can effectively improve the barrier property of the film. Bio-based epoxidized soybean oil is a stable and biodegradable plasticizer, which complies with the US FDA food additive regulations and the EU RoHS environmental protection directive and REACH regulations; it is rich in epoxy groups, which can react with the surface hydroxyl groups of the intercalated modified coal-based kaolin and graft onto the surface of kaolin to improve its dispersibility in the PBAT / PLA film. PBAT is polybutylene adipate terephthalate, and PLA is polylactic acid. The remaining epoxy groups can react with biodegradable materials during the melt blending process to form graft copolymers, improving the compatibility of various biodegradable materials and further enhancing the barrier property of the biodegradable mulch film material.

[0020] 2. By intercalating and modifying coal-based kaolin with urea, the layer spacing of kaolin is increased, and it is rich in nitrogen fertilizer, becoming a slow-release granule. Through calcination, the surface active hydroxyl sites are more prone to react with bio-based epoxidized soybean oil. The residual epoxy groups react with biodegradable polymers during the melt blending process to improve the compatibility between biodegradable polymer materials. This preparation method makes kaolin multifunctional, which not only solves the dispersibility of kaolin, increases the layer spacing, and enhances the barrier property, but also endows it with the functions of slow-release nitrogen fertilizer and compatibilization. The preparation process is simple, easy to operate, does not require large-scale adjustment of the existing process, and is suitable for large-scale popularization and application. Description of the Drawings

[0021] Figure 1 It is a comparative scanning electron microscope image of the brittle fracture surface of the high-barrier slow-release nitrogen fertilizer biodegradable mulch film prepared in Example 1 of the present invention and the PBAT / PLA film. Detailed Embodiments

[0022] Example 1

[0023] A high-barrier slow-release nitrogen fertilizer biodegradable mulch material, comprising the following raw materials: expanded nitrogen-rich intercalated modified coal-based kaolin and a composite bio-based material; the mass ratio of the expanded nitrogen-rich intercalated modified coal-based kaolin to the composite bio-based material is 1:9; the composite bio-based material is a mixture of polyadipate / butylene terephthalate and polylactic acid in a mass ratio of 9:1;

[0024] The preparation process of the expanded nitrogen-rich intercalated modified coal-based kaolin is as follows:

[0025] I. Preparation of nitrogen-enriched intercalation modified coal-based kaolin: prepare an aqueous urea solution with a concentration of 80%, weigh the coal-based kaolin and add it to the urea aqueous solution in a mass ratio of 1:10, stir and mix evenly, react for 6 hours under ultrasonic, stirring and constant temperature water bath conditions, the temperature of the constant temperature water bath is 60°C, cool, filter, wash and vacuum dry after the reaction to obtain nitrogen-enriched intercalation modified coal-based kaolin;

[0026] II. Preparation of expanded nitrogen-rich intercalation modified coal-based kaolin: calcine the nitrogen-rich intercalation modified coal-based kaolin obtained in step I at 105°C for 1 hour, cool after calcination, mix evenly with N,N-dimethylformamide, add bio-based epoxy soybean oil and triethylamine for reaction, the mass ratio of triethylamine to bio-based epoxy soybean oil is 1:3, the mass ratio of bio-based epoxy soybean oil to nitrogen-rich intercalation modified coal-based kaolin is 3:1, cool, filter, wash, and vacuum dry to obtain expanded nitrogen-rich intercalation modified coal-based kaolin. The mass ratio of triethylamine to nitrogen-rich intercalation modified coal-based kaolin is 1:10.

[0027] The above-mentioned method for preparing a high-barrier slow-release nitrogen fertilizer biodegradable mulch material comprises the following steps: evenly mixing the expanded nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based material, mixing and granulating with a twin-screw extruder, water cooling, and pelletizing, and then blowing out through a film blowing machine, wherein the seven-section temperatures of the twin-screw extruder are: 135°C, 145°C, 150°C, 155°C, 155°C, 160°C, and 160°C, and the rotation speed is 270rpm; the four-section temperatures of the film blowing machine are: 145°C, 150°C, 150°C, and 150°C, and the rotation speed is 50rpm, to obtain the high-barrier slow-release nitrogen fertilizer biodegradable mulch material.

[0028] Comparative Example 1

[0029] The difference from Example 1 is that only composite bio-based materials are used as raw materials. Other technical solutions are the same as those in Example 1.

[0030] According to the analysis and test, the PBAT / PLA / enhanced nitrogen-rich intercalated modified coal-based kaolin biodegradable mulch film prepared in Example 1 (i.e., the high-barrier slow-release nitrogen fertilizer biodegradable mulch film material) and the PBAT / PLA mulch film obtained in Comparative Example 1 have water vapor transmission rates of 710 g / m 2 ·24 h and 580 g / m 2 ·24 h, indicating that the biodegradable mulch film material prepared in this application has good moisture retention function.

[0031] Reference Figure 1 , the left figure is the scanning electron micrograph of the brittle fracture surface of the PBAT / PLA film in Comparative Example 1, and the right figure is the scanning electron micrograph of the brittle fracture surface of the PBAT / PLA / enhanced nitrogen-rich intercalated modified coal-based kaolin biodegradable mulch film obtained by this technical solution (i.e., the high-barrier slow-release nitrogen fertilizer biodegradable mulch film material). By comparison, it is found that the enhanced nitrogen-rich intercalated modified coal-based kaolin is evenly dispersed in the high-barrier slow-release nitrogen fertilizer biodegradable mulch film, and no agglomeration phenomenon is observed, which well improves the barrier performance of the existing biodegradable film. And since it completely uses biodegradable materials, it remains green and environmentally friendly during the preparation and use process. It is a high-barrier biodegradable film with excellent safety, ecology and barrier performance worthy of being vigorously promoted.

[0032] Example 2

[0033] A high-barrier slow-release nitrogen fertilizer biodegradable mulch film material, comprising the following raw materials: enhanced nitrogen-rich intercalated modified coal-based kaolin, composite bio-based material; the mass ratio of the enhanced nitrogen-rich intercalated modified coal-based kaolin to the composite bio-based material is 1:20; the composite bio-based material is a mixture mixed according to the mass ratio of polybutylene adipate / terephthalate and poly(propylene carbonate) of 4:1;

[0034] Among them, the preparation process of the enhanced nitrogen-rich intercalated modified coal-based kaolin is as follows:

[0035] I. Preparation of nitrogen-rich intercalated modified coal-based kaolin: Prepare an 80% urea aqueous solution. According to the mass ratio of coal-based kaolin to urea aqueous solution of 1:15, weigh coal-based kaolin and add it to the urea aqueous solution, stir and mix evenly, react for 12 h under the conditions of ultrasonic, stirring and constant temperature water bath, the temperature of the constant temperature water bath is 70 °C, after the reaction, cool, filter, wash and vacuum dry to obtain nitrogen-rich intercalated modified coal-based kaolin;

[0036] II. Preparation of expanded nitrogen-rich intercalation modified coal-based kaolin: calcine the nitrogen-rich intercalation modified coal-based kaolin obtained in step I at 150°C for 0.5h, cool after calcination, mix evenly with N,N-dimethylacetamide, add bio-based epoxy soybean oil and triethylamine for reaction, the mass ratio of triethylamine to bio-based epoxy soybean oil is 1:5, the mass ratio of bio-based epoxy soybean oil to nitrogen-rich intercalation modified coal-based kaolin is 5:1, cool, filter, wash, and vacuum dry to obtain expanded nitrogen-rich intercalation modified coal-based kaolin. The mass ratio of triethylamine to nitrogen-rich intercalation modified coal-based kaolin is 1:10.

[0037] The above-mentioned method for preparing a high-barrier slow-release nitrogen fertilizer biodegradable mulch material comprises the following steps: evenly mixing the expanded nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based material, mixing and granulating with a twin-screw extruder, water cooling, and pelletizing, and then blowing out through a film blowing machine, wherein the seven-section temperatures of the twin-screw extruder are: 135°C, 145°C, 150°C, 155°C, 155°C, 160°C, and 160°C, and the rotation speed is 270rpm; the four-section temperatures of the film blowing machine are: 145°C, 150°C, 150°C, and 150°C, and the rotation speed is 50rpm, to obtain the high-barrier slow-release nitrogen fertilizer biodegradable mulch material.

[0038] Comparative Example 2

[0039] The difference from Example 2 is that only composite bio-based materials are used as raw materials. Other technical solutions are the same as those in Example 2.

[0040] According to the analysis and test, the water vapor permeability of the PBAT / PLA / enlarged nitrogen-rich intercalated modified coal-based kaolin biodegradable mulch prepared in Example 2 (i.e., the high barrier slow-release nitrogen fertilizer biodegradable mulch material) and the PBAT / PLA mulch prepared in Comparative Example 2 are 647 g / m 2 24h and 420g / m 2 ·24h, indicating that the biodegradable mulch film material prepared by the present application has good moisture retention function.

[0041] Example 3

[0042] A high-barrier slow-release nitrogen fertilizer biodegradable mulch material, comprising the following raw materials: expanded nitrogen-rich intercalated modified coal-based kaolin and a composite bio-based material; the mass ratio of the expanded nitrogen-rich intercalated modified coal-based kaolin to the composite bio-based material is 1:30; the composite bio-based material is a mixture of polyadipate / butylene terephthalate and polypropylene carbonate in a mass ratio of 8:1;

[0043] The preparation process of the expanded nitrogen-rich intercalated modified coal-based kaolin is as follows:

[0044] I. Preparation of nitrogen-enriched intercalation modified coal-based kaolin: prepare an aqueous urea solution with a concentration of 80%, weigh the coal-based kaolin and add it to the urea aqueous solution in a mass ratio of 1:1, stir and mix evenly, react for 6 hours under ultrasonic, stirring and constant temperature water bath conditions, the temperature of the constant temperature water bath is 80°C, cool, filter, wash and vacuum dry after the reaction to obtain nitrogen-enriched intercalation modified coal-based kaolin;

[0045] II. Preparation of expanded nitrogen-rich intercalation modified coal-based kaolin: calcine the nitrogen-rich intercalation modified coal-based kaolin obtained in step I at 180°C for 0.5h, cool after calcination, mix evenly with N,N-dimethylformamide, add bio-based epoxy soybean oil and triphenylphosphine for reaction, the mass ratio of triphenylphosphine to bio-based epoxy soybean oil is 1:9, the mass ratio of bio-based epoxy soybean oil to nitrogen-rich intercalation modified coal-based kaolin is 10:1, cool, filter, wash, and vacuum dry to obtain expanded nitrogen-rich intercalation modified coal-based kaolin. The mass ratio of triphenylphosphine to nitrogen-rich intercalation modified coal-based kaolin is 1:10.

[0046] The above-mentioned method for preparing a high-barrier slow-release nitrogen fertilizer biodegradable mulch material comprises the following steps: evenly mixing the expanded nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based material, mixing and granulating with a twin-screw extruder, water cooling, and pelletizing, and then blowing out through a film blowing machine, wherein the seven-section temperatures of the twin-screw extruder are: 135°C, 145°C, 150°C, 155°C, 155°C, 160°C, and 160°C, and the rotation speed is 270rpm; the four-section temperatures of the film blowing machine are: 145°C, 150°C, 150°C, and 150°C, and the rotation speed is 50rpm, to obtain the high-barrier slow-release nitrogen fertilizer biodegradable mulch material.

[0047] Comparative Example 3

[0048] The difference from Example 3 is that only composite bio-based materials are used as raw materials. Other technical solutions are the same as those in Example 3.

[0049] According to the analysis and test, the water vapor permeability of the PBAT / PLA / enlarged nitrogen-rich intercalated modified coal-based kaolin biodegradable mulch prepared in Example 3 (i.e., the high barrier slow-release nitrogen fertilizer biodegradable mulch material) and the PBAT / PLA mulch prepared in Comparative Example 3 are 715 g / m 2 24h and 450g / m 2 ·24h, indicating that the biodegradable mulch film material prepared by the present application has good moisture retention function.

[0050] Example 4

[0051] A high-barrier slow-release nitrogen fertilizer biodegradable mulch film material, comprising the following raw materials: compatibilized nitrogen-rich intercalated modified coal-based kaolin, composite bio-based material; the mass ratio of the compatibilized nitrogen-rich intercalated modified coal-based kaolin to the composite bio-based material is 1:40; the composite bio-based material is: a mixture prepared by mixing polybutylene adipate / terephthalate and poly(propylene carbonate) in a mass ratio of 7:1;

[0052] Among them, the preparation process of the compatibilized nitrogen-rich intercalated modified coal-based kaolin is as follows:

[0053] I. Preparation of nitrogen-rich intercalated modified coal-based kaolin: Prepare an 80% urea aqueous solution. According to the mass ratio of coal-based kaolin to urea aqueous solution of 1:20, weigh coal-based kaolin and add it to the urea aqueous solution, stir and mix evenly, react for 12 h under the conditions of ultrasonic, stirring, and constant temperature water bath. The temperature of the constant temperature water bath is 60 °C. After the reaction, cool, filter, wash, and vacuum dry to obtain nitrogen-rich intercalated modified coal-based kaolin;

[0054] II. Preparation of compatibilized nitrogen-rich intercalated modified coal-based kaolin: Calcinate the nitrogen-rich intercalated modified coal-based kaolin obtained in step I at 130 °C for 1 h. After calcination, cool, then mix evenly with N,N-dimethylformamide, add bio-based epoxy soybean oil and triphenylphosphine to react. The mass ratio of triphenylphosphine to bio-based epoxy soybean oil is 1:3, and the mass ratio of bio-based epoxy soybean oil to nitrogen-rich intercalated modified coal-based kaolin is 3:1. Cool, filter, wash, and vacuum dry to obtain compatibilized nitrogen-rich intercalated modified coal-based kaolin. The mass ratio of triphenylphosphine to nitrogen-rich intercalated modified coal-based kaolin is 1:10.

[0055] The preparation method of the above-mentioned high-barrier slow-release nitrogen fertilizer biodegradable mulch film material comprises the following steps: Mix the compatibilized nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based material evenly, carry out mixing and granulation, water cooling, and pelletizing with a twin-screw extruder, and then blow it out with a blown film machine. The seven-section temperature of the twin-screw extruder is: 135 °C, 145 °C, 150 °C, 155 °C, 155 °C, 160 °C, 160 °C, and the rotation speed is 270 rpm; the four-section temperature of the blown film machine is: 145 °C, 150 °C, 150 °C, 150 °C, and the rotation speed is 50 rpm to obtain the high-barrier slow-release nitrogen fertilizer biodegradable mulch film material.

[0056] Comparative Example 4

[0057] The difference from Example 4 is that only the composite bio-based material is used in terms of raw materials. Other technical solutions are the same as those in Example 4.

[0058] According to the analysis and test, the PBAT / PLA / nitrogen-rich intercalation modified coal-based kaolin biodegradable mulch film prepared in Example 4 (i.e., the high-barrier slow-release nitrogen fertilizer biodegradable mulch film material) and the PBAT / PLA mulch film obtained in Comparative Example 4 have water vapor transmission rates of 670 g / m 2 ·24 h and 357 g / m 2 ·24 h, indicating that the biodegradable mulch film material prepared in this application has good soil moisture conservation function.

[0059] Unless otherwise specified, the raw materials used in the present invention are all common commercially available drugs in the art. The instruments and devices used in the present invention are also conventional instruments and equipment in the art. The test method for the water vapor transmission coefficient index involved in the present invention is as follows: According to the GB / T 1037-1988 standard, the water vapor transmission rate of the film is measured using a W3 / 031 type water vapor transmission rate tester, the test temperature is 3 °C, the humidity is 90 RH%, and 5 parallel samples are tested for each group of samples.

[0060] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in terms of form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all of them are within the protection scope of the present invention.

Claims

1. A high barrier slow-release nitrogen fertilizer biodegradable mulch material, characterized in that: The water vapor permeability coefficient of the high barrier slow-release nitrogen fertilizer biodegradable mulch film material is 300-600 g / m 2 24h; The invention comprises the following raw materials: expanded nitrogen-rich intercalated modified coal-based kaolin and composite bio-based materials; the mass ratio of the expanded nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based materials is 1:9-99; the composite bio-based materials are one or a mixture of any proportion of poly(adipate / butylene terephthalate), poly(lactic acid) or poly(propylene carbonate); The preparation process of the expanded nitrogen-rich intercalated modified coal-based kaolin is as follows: I. Preparation of nitrogen-enriched intercalation modified coal-based kaolin: prepare a 60-80% urea aqueous solution, weigh the coal-based kaolin and add it to the urea aqueous solution in a mass ratio of 1:1-20, stir and mix evenly, react for 6-12 hours under ultrasonic, stirring and constant temperature water bath conditions, and after the reaction is completed, cool, filter, wash and vacuum dry in sequence to obtain nitrogen-enriched intercalation modified coal-based kaolin; II. Preparation of expanded nitrogen-rich intercalated modified coal-based kaolin: calcine the nitrogen-rich intercalated modified coal-based kaolin obtained in step I at 100-180°C for 0.5-1h, cool after calcination, mix evenly with an organic solvent, add bio-based epoxidized soybean oil and a catalyst for reaction, cool, filter, wash and vacuum dry in sequence to obtain expanded nitrogen-rich intercalated modified coal-based kaolin.

2. The high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 1, characterized in that: The temperature of the constant temperature water bath is 50-80°C.

3. The high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 1, characterized in that: The organic solvent is any one of dichloromethane, chloroform, trichloroethane, N,N-dimethylformamide or N,N-dimethylacetamide.

4. The high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 1, characterized in that: The catalyst is any one of triphenylphosphine, triethylamine or benzyltriethylammonium chloride.

5. The high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 1, characterized in that: The mass ratio of the catalyst to the bio-based epoxidized soybean oil is 1:3-9, and the mass ratio of the bio-based epoxidized soybean oil to the nitrogen-rich intercalated modified coal-based kaolin is 3-10:

1.

6. The method for preparing a high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 1, characterized in that: The following steps are involved: The expanded nitrogen-rich intercalated modified coal-based kaolin and the composite bio-based material are mixed evenly, mixed and granulated by a twin-screw extruder, water-cooled, and pelletized, and then blown out by a film blowing machine to obtain the high-barrier slow-release nitrogen fertilizer biodegradable mulch film material.

7. The method for preparing a high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 5, characterized in that: The seven-stage temperatures of the twin-screw extruder are: 120-135°C, 120-145°C, 140-150°C, 140-155°C, 140-155°C, 140-160°C, 140-160°C, and the rotation speed is 200-270rpm.

8. The method for preparing a high barrier slow-release nitrogen fertilizer biodegradable mulch material according to claim 5, characterized in that: The four-stage temperature of the film blowing machine is: 130-145°C, 130-150°C, 130-150°C, 130-150°C, and the rotation speed is 35-50rpm.

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