Super-hydrophobic plant fiber agricultural film and preparation method thereof

Abstract

The invention relates to a super-hydrophobic plant fiber agricultural film and a preparation method thereof, and belongs to the technical field of agricultural materials. The super-hydrophobic plant fiber agricultural film is prepared by taking a plant fiber base material, alkyl ketene dimer wax powder and self-made super-hydrophobic modified starch as raw materials, and is prepared by the following steps: firstly, heating and melting the alkyl ketene dimer wax powder, then adding the alkyl ketene dimer wax powder into a hot sodium hydroxide solution, and carrying out high-speed shearing and stirring to obtain an AKD (Alkyl Ketene Dimer) emulsion; then adding self-made super-hydrophobic modified starch into the obtained AKD emulsion, shearing and stirring again to obtain a super-hydrophobic AKD emulsion, and finally coating the surface of a plant fiber base material with the super-hydrophobic AKD emulsion and drying to obtain the super-hydrophobic plant fiber agricultural film. The surface of the super-hydrophobic plant fiber agricultural film is super-hydrophobic, the super-hydrophobic plant fiber agricultural film is soft in texture, easy to bend and good in water resistance, does not contain fluorine, silicon and other refractory elements, does not contain any element harmful to agricultural production, and is environmentally friendly and free of pollution.

Description

Technical Field

[0001] The invention belongs to the technical field of agricultural materials, and in particular, relates to a super-hydrophobic plant fiber agricultural film and a preparation method thereof. Background Art

[0002] Plant fiber paper is paper made from plant fiber as raw material. Plant fiber comes from various plants, such as hemp, mulberry, chu, rattan, celery, bamboo and wood, etc. It is a recyclable material, does not pollute the environment, is not easy to deform, not easy to rot, and is not easily eroded by pests. It is an ideal material for agricultural materials. However, the surface of this type of paper is generally hydrophilic and easily affected by moisture. Based on this, the present invention provides a super-hydrophobic plant fiber agricultural film and a preparation method thereof. Summary of the invention

[0003] The object of the present invention is to provide a super-hydrophobic plant fiber agricultural film and a preparation method thereof, so as to solve the problems mentioned in the above background technology.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A super-hydrophobic plant fiber agricultural film comprises the following raw materials: a plant fiber substrate, alkyl ketene dimer wax powder, and super-hydrophobic modified starch;

[0006] A method for preparing a super-hydrophobic plant fiber agricultural film comprises the following steps:

[0007] The first step is to heat and melt the alkyl ketene dimer wax powder, add it into a sodium hydroxide aqueous solution, and stir it at high speed to obtain an AKD emulsion;

[0008] Step 2: adding super-hydrophobic modified starch to the AKD emulsion, and cooling the material with cold water after high-speed shear stirring to obtain a super-hydrophobic AKD emulsion;

[0009] The third step is to coat the super-hydrophobic AKD emulsion on the surface of the plant fiber substrate and dry and solidify it to obtain a super-hydrophobic plant fiber agricultural film.

[0010] Furthermore, in the first step, the temperature at which the alkyl ketene dimer wax powder is heated is 65-75°C.

[0011] Furthermore, the temperature of the sodium hydroxide aqueous solution in the first step is 75° C., and the pH value is 8.5-9.5.

[0012] Furthermore, in the first step, the rotation speed condition of the high-speed shear stirring is 3000-3600 rpm, and the time condition of the high-speed shear stirring is 3-4 min.

[0013] Furthermore, in the second step, the rotation speed condition of the high-speed shear stirring is 7600-8400 rpm, and the time condition of the high-speed shear stirring is 10-12 min.

[0014] Furthermore, the usage ratio of the alkyl ketene dimer wax powder, the sodium hydroxide aqueous solution and the super-hydrophobic modified starch is 1 part: 10-12 parts: 0.7-0.9 parts by mass.

[0015] Furthermore, the coating thickness of the AKD emulsion in the third step is preferably 1 mm.

[0016] Furthermore, the plant fiber substrate is preferably one of flax fiber paper, jute fiber paper and ramie fiber paper.

[0017] Furthermore, the super hydrophobic modified starch is prepared by the following steps:

[0018] Step 1, p-formylphenylboronic acid, acetone, sodium hydroxide and ethanol solution were mixed in a three-necked flask, magnetic stirring was turned on, and the reaction was carried out at room temperature for 1 hour. After the reaction was completed, the reaction solution was spin-dried, and the obtained solid was washed with deionized water and dried to obtain intermediate 1;

[0019] Step 2, starch and deionized water are mixed in a three-necked flask, a condenser and a thermometer are installed, magnetic stirring is turned on, the system temperature is raised to 80°C under nitrogen protection, gelatinized at 80°C for 1 hour, the system temperature is lowered to 60°C, and a dilute nitric acid solution of ammonium cerium nitrate is added to the three-necked flask, and after the addition is completed, an ethanol solution of intermediate 1 is added dropwise to the three-necked flask for 0.5 hours. After the addition is completed, the reaction is carried out at 60°C for 3 hours. After the reaction is completed, vacuum filtration is performed, and the obtained solid is washed with ethanol and dried to obtain a grafted modified starch;

[0020] Step 3, the grafted modified starch, stearyl glycol, and ethanol solution are mixed in a three-necked flask, a condenser and a thermometer are installed, magnetic stirring is turned on, and the pH of the system is adjusted to 9-10 with a 10% mass fraction of sodium hydroxide aqueous solution. Then, the system temperature is raised to 80°C under nitrogen protection conditions, and then stirred at 80°C for 1h. After the reaction is completed, vacuum filtration is performed, and the obtained solid is washed with ethanol and dried to obtain super hydrophobic modified starch.

[0021] Furthermore, the ethanol solution used in step 1 is an ethanol aqueous solution with a volume fraction of 95%.

[0022] Furthermore, the dosage ratio of p-formylphenylboric acid, acetone, sodium hydroxide and ethanol solution used in step 1 is 0.05 mol: 0.025 mol: 6-8 g: 30-40 mL.

[0023] Furthermore, the dilute nitric acid solution of ammonium cerium nitrate used in step 2 is prepared from 2.7 g of ammonium cerium nitrate and 15 mL of dilute nitric acid with a mass fraction of 10%.

[0024] Furthermore, the ethanol solution of intermediate 1 used in step 2 is prepared from 0.02 mol of intermediate 2 and 30 mL of anhydrous ethanol.

[0025] Furthermore, the amount ratio of starch, deionized water, dilute nitric acid solution of ammonium cerium nitrate, and ethanol solution of intermediate 1 used in step 2 is 30g:120-150mL:18.52g:30.1g.

[0026] Furthermore, the ethanol solution used in step 3 is an ethanol aqueous solution with a volume fraction of 10%.

[0027] Furthermore, the amount ratio of the grafted modified starch, stearyl glycol and ethanol solution used in step 3 is 30-35 g: 0.06-0.1 mol: 150-180 mL.

[0028] Beneficial effects of the present invention:

[0029] 1) The present invention uses a plant fiber substrate, an alkyl ketene dimer wax powder, and a self-made super-hydrophobic modified starch as raw materials to prepare a super-hydrophobic plant fiber film. The present invention heats and melts the alkyl ketene dimer wax powder, then adds the mixture into a hot sodium hydroxide solution and shears and stirs it at a high speed to obtain an AKD emulsion, then adds the self-made super-hydrophobic modified starch into the obtained AKD emulsion, shears and stirs it again to obtain a super-hydrophobic AKD emulsion, and finally coats the super-hydrophobic AKD emulsion on the surface of the plant fiber substrate and dries it to obtain a super-hydrophobic plant fiber agricultural film. The surface of the super-hydrophobic plant fiber agricultural film provided by the present invention has a layer of super-hydrophobic AKD coating, has good water resistance, and is not easily affected by water immersion.

[0030] 2) The present invention uses p-formylphenylboronic acid and acetone as raw materials, utilizes the formyl group of p-formylphenylboronic acid and α-hydrogen of acetone to undergo Claisen-Smidt reaction to obtain an intermediate 1 with two double bonds, and then the double bonds of the intermediate 1 are grafted into starch under the action of an initiator, ammonium cerium nitrate, to obtain a grafted modified starch, and finally the boric acid group of the grafted modified starch loaded with the intermediate 1 on the surface undergoes an esterification reaction with the 1,2-dihydroxy structure of stearyl glycol in an alkaline environment to obtain a super-hydrophobic modified starch having a borate structure. The surface of the super-hydrophobic modified starch of the present invention has a long-chain alkyl structure and a borate structure, and the surface is super-hydrophobic, which can reduce the intermolecular force, make the AKD emulsion film-forming softer, and reduce the surface energy at the same time, so that the AKD emulsion has a good water-resistant effect after film-forming, and the super-hydrophobic modified starch of the present invention does not contain difficult-to-degrade elements such as fluorine and silicon, belongs to a degradable material, and is safe and pollution-free.

[0031] 3) The super-hydrophobic plant fiber agricultural film of the present invention has a super-hydrophobic surface, is soft and easy to bend, has good water resistance, does not contain fluorine, silicon and other difficult-to-degrade elements, does not contain any elements harmful to agricultural production, and is environmentally friendly and pollution-free. DETAILED DESCRIPTION

[0032] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] A super hydrophobic modified starch is prepared by the following steps:

[0035] Step 1, 0.05 mol of p-formylphenylboronic acid, 0.025 mol of acetone, 6 g of sodium hydroxide, and 30 mL of 95% by volume ethanol aqueous solution were mixed in a three-necked flask, magnetic stirring was turned on, and the mixture was reacted at room temperature for 1 h. After the reaction was completed, the reaction solution was spin-dried, and the obtained solid was washed with deionized water and dried to obtain intermediate 1;

[0036] Step 2, 30g starch and 120mL deionized water were mixed in a three-necked flask, a condenser and a thermometer were installed, magnetic stirring was turned on, and the system temperature was raised to 80°C under nitrogen protection conditions. After gelatinization at 80°C for 1h, the system temperature was lowered to 60°C, and 18.52g of a solution prepared by 2.7g cerium ammonium nitrate and 15mL of 10% dilute nitric acid was added to the three-necked flask. After the addition was completed, 30.1g of a solution prepared by 0.02mol intermediate 1 and 30mL of anhydrous ethanol was added dropwise to the three-necked flask. The addition time was 0.5h. After the addition was completed, the reaction was carried out at a temperature of 60°C for 3h. After the reaction was completed, vacuum filtration was performed, and the obtained solid was washed with ethanol and dried to obtain grafted modified starch;

[0037] Step 3, 30g of grafted modified starch, 0.06mol of stearyl glycol, and 150mL of 10% ethanol aqueous solution were mixed in a three-necked flask, a condenser and a thermometer were installed, magnetic stirring was turned on, and the pH of the system was adjusted to 9 with a 10% mass fraction of sodium hydroxide aqueous solution. Then, the system temperature was raised to 80°C under nitrogen protection, and the reaction was stirred at 80°C for 1h. After the reaction was completed, vacuum filtration was performed, and the obtained solid was washed with ethanol and dried to obtain super hydrophobic modified starch.

[0038] Example 2

[0039] A super hydrophobic modified starch is prepared by the following steps:

[0040] Step 1, 0.05 mol of p-formylphenylboronic acid, 0.025 mol of acetone, 7 g of sodium hydroxide, and 35 mL of 95% by volume ethanol aqueous solution were mixed in a three-necked flask, magnetic stirring was turned on, and the mixture was reacted at room temperature for 1 h. After the reaction was completed, the reaction solution was spin-dried, and the obtained solid was washed with deionized water and dried to obtain intermediate 1;

[0041] Step 2, 30g starch and 135mL deionized water were mixed in a three-necked flask, a condenser and a thermometer were installed, magnetic stirring was turned on, and the system temperature was raised to 80°C under nitrogen protection conditions. After gelatinization at 80°C for 1h, the system temperature was lowered to 60°C, and 18.52g of a solution prepared by 2.7g cerium ammonium nitrate and 15mL of 10% by mass dilute nitric acid was added to the three-necked flask. After the addition was completed, 30.1g of a solution prepared by 0.02mol of intermediate 1 and 30mL of anhydrous ethanol was added dropwise to the three-necked flask. The addition time was 0.5h. After the addition was completed, the reaction was carried out at a temperature of 60°C for 3h. After the reaction was completed, vacuum filtration was performed, and the obtained solid was washed with ethanol and dried to obtain grafted modified starch;

[0042] Step 3, 32.5g grafted modified starch, 0.08mol stearyl glycol, and 165mL of 10% ethanol aqueous solution were mixed in a three-necked flask, a condenser and a thermometer were installed, magnetic stirring was turned on, and the pH of the system was adjusted to 9.5 with a 10% mass fraction of sodium hydroxide aqueous solution. Then, the system temperature was raised to 80°C under nitrogen protection, and the reaction was stirred at 80°C for 1h. After the reaction was completed, vacuum filtration was performed, and the obtained solid was washed with ethanol and dried to obtain super hydrophobic modified starch.

[0043] Example 3

[0044] A super hydrophobic modified starch is prepared by the following steps:

[0045] Step 1, 0.05 mol of p-formylphenylboronic acid, 0.025 mol of acetone, 8 g of sodium hydroxide, and 40 mL of 95% by volume ethanol aqueous solution were mixed in a three-necked flask, magnetic stirring was turned on, and the mixture was reacted at room temperature for 1 h. After the reaction was completed, the reaction solution was spin-dried, and the obtained solid was washed with deionized water and dried to obtain intermediate 1;

[0046] Step 2: Mix 30 g of starch and 150 mL of deionized water in a three-necked flask. Install a condenser and a thermometer, turn on magnetic stirring, and raise the temperature of the system to 80 °C under nitrogen protection. After gelatinization at 80 °C for 1 h, lower the temperature of the system to 60 °C, and add 18.52 g of a solution prepared from 2.7 g of ammonium cerium nitrate and 15 mL of 10% by mass dilute nitric acid to the three-necked flask. After the addition is complete, add dropwise 30.1 g of a solution prepared from 0.02 mol of Intermediate 1 and 30 mL of absolute ethanol to the three-necked flask over 0.5 h. After the dropwise addition is complete, react at 60 °C for 3 h. After the reaction is complete, perform vacuum filtration. The obtained solid is washed with ethanol and then dried to obtain graft-modified starch;

[0047] Step 3: Mix 35 g of graft-modified starch, 0.1 mol of stearic diol, and 180 mL of 10% by volume ethanol aqueous solution in a three-necked flask. Install a condenser and a thermometer, turn on magnetic stirring, adjust the pH of the system to 10 with 10% by mass sodium hydroxide aqueous solution, then raise the temperature of the system to 80 °C under nitrogen protection, and then stir and react at 80 °C for 1 h. After the reaction is complete, perform vacuum filtration. The obtained solid is washed with ethanol and then dried to obtain superhydrophobic modified starch.

[0048] Example 4

[0049] A superhydrophobic plant fiber agricultural film comprises the following raw materials: flax fiber paper, alkyl ketene dimer wax powder, and the superhydrophobic modified starch obtained in Example 1;

[0050] A preparation method of a superhydrophobic plant fiber agricultural film comprises the following steps:

[0051] First step: Heat the alkyl ketene dimer wax powder to 65 °C until it melts, then add it to a sodium hydroxide aqueous solution with a pH of 8.5 at 75 °C and perform shear stirring at 3000 rpm for 3 min to obtain an AKD emulsion;

[0052] Second step: Add the superhydrophobic modified starch obtained in Example 1 to the AKD emulsion, perform shear stirring at 7600 rpm for 10 min, and then cool and discharge with cold water to obtain a superhydrophobic AKD emulsion;

[0053] Third step: Coat the superhydrophobic AKD emulsion on the surface of the flax fiber paper with a film thickness of 1 mm, and then dry and cure to obtain a superhydrophobic plant fiber agricultural film.

[0054] By mass fraction, the dosage ratio of the alkyl ketene dimer wax powder, sodium hydroxide aqueous solution, and superhydrophobic modified starch obtained in Example 1 used in this example is 1 part: 10 parts: 0.7 part.

[0055] Example 5

[0056] A super-hydrophobic plant fiber agricultural film, comprising the following raw materials: jute fiber paper, alkyl ketene dimer wax powder, and the super-hydrophobic modified starch obtained in Example 2;

[0057] A method for preparing a super-hydrophobic plant fiber agricultural film comprises the following steps:

[0058] The first step is to heat the alkyl ketene dimer wax powder to 70°C and melt it, then add it into a sodium hydroxide aqueous solution with a temperature of 75°C and a pH value of 8.5-9.5, and shear and stir it at a speed of 3300 rpm for 3.5 minutes to obtain an AKD emulsion;

[0059] Step 2: adding the super-hydrophobic modified starch obtained in Example 2 to the AKD emulsion, and shearing and stirring for 11 min at a speed of 8000 rpm, and then cooling the material with cold water to obtain a super-hydrophobic AKD emulsion;

[0060] The third step is to coat the super-hydrophobic AKD emulsion on the surface of the jute fiber paper with a coating thickness of 1 mm, and then dry and solidify it to obtain a super-hydrophobic plant fiber agricultural film.

[0061] In terms of mass fractions, the usage ratio of the alkyl ketene dimer wax powder, the sodium hydroxide aqueous solution, and the super-hydrophobic modified starch obtained in Example 2 used in this example is 1 part: 11 parts: 0.8 parts.

[0062] Example 6

[0063] A super-hydrophobic plant fiber agricultural film, comprising the following raw materials: ramie fiber paper, alkyl ketene dimer wax powder, and the super-hydrophobic modified starch obtained in Example 3;

[0064] A method for preparing a super-hydrophobic plant fiber agricultural film comprises the following steps:

[0065] The first step is to heat the alkyl ketene dimer wax powder to 75°C to melt it, then add it into a sodium hydroxide aqueous solution with a temperature of 75°C and a pH value of 9.5, and shear and stir it at a speed of 3600 rpm for 4 minutes to obtain an AKD emulsion;

[0066] Step 2: adding the super-hydrophobic modified starch obtained in Example 3 to the AKD emulsion, and then cooling the material with cold water at a speed of 8400 rpm for 12 min to obtain a super-hydrophobic AKD emulsion;

[0067] The third step is to coat the super-hydrophobic AKD emulsion on the surface of the ramie fiber paper with a coating thickness of 1 mm, and then dry and solidify it to obtain a super-hydrophobic plant fiber agricultural film.

[0068] In terms of mass fractions, the usage ratio of the alkyl ketene dimer wax powder, the sodium hydroxide aqueous solution, and the super-hydrophobic modified starch obtained in Example 3 used in this example is 1 part: 12 parts: 0.9 parts.

[0069] Comparative Example 1

[0070] A super-hydrophobic plant fiber agricultural film comprises the following raw materials: ramie fiber paper, alkyl ketene dimer wax powder, and starch;

[0071] A method for preparing a super-hydrophobic plant fiber agricultural film comprises the following steps:

[0072] The first step is to heat the alkyl ketene dimer wax powder to 75°C to melt it, then add it into a sodium hydroxide aqueous solution with a temperature of 75°C and a pH value of 9.5, and shear and stir it at a speed of 3600 rpm for 4 minutes to obtain an AKD emulsion;

[0073] Step 2: Add starch to the AKD emulsion, and then cool the mixture with cold water to obtain a super hydrophobic AKD emulsion after shear stirring at a speed of 8400 rpm for 12 min.

[0074] The third step is to coat the super-hydrophobic AKD emulsion on the surface of the ramie fiber paper with a coating thickness of 1 mm, and then dry and solidify it to obtain a super-hydrophobic plant fiber agricultural film.

[0075] In terms of mass fractions, the usage ratio of the alkyl ketene dimer wax powder, the sodium hydroxide aqueous solution, and the starch used in this embodiment is 1 part:12 parts:0.9 parts.

[0076] Experimental Example 1

[0077] The performance of the super-hydrophobic plant fiber agricultural film in Examples 4-6 and Comparative Example 1 was tested together. The surface water contact angle was tested using a water contact angle tester produced by Dataphysics of Germany after the agricultural films of each component were cut. The test results are shown in Table 1:

[0078] Table 1

[0079] project Water contact angle (°) Example 4 152 Example 5 156 Example 6 157 Comparative Example 1 82

[0080] It can be seen from Table 1 that the surface water contact angles of the super-hydrophobic plant fiber agricultural film of the present invention in Examples 4-6 are all greater than 150°, meeting the requirement of surface super-hydrophobicity, while the water contact angle of the super-hydrophobic plant fiber agricultural film in Comparative Example 1 is less than 90°, and it still belongs to a hydrophilic material. The reason is that the super-hydrophobic modified starch of the present invention was not selected. The large amount of hydrophilic hydroxyl groups in the unmodified starch improves the hydrophilicity of the surface AKD coating. In summary, the surface of the super-hydrophobic plant fiber agricultural film of the present invention can achieve super-hydrophobicity, has good water resistance, is not easily affected by water immersion, and can be widely used in the field of agricultural materials.

[0081] A kind of super-hydrophobic plant fiber agricultural film and preparation method thereof provided by the present invention are introduced in detail above, and specific examples are applied herein to explain the principle and implementation mode of the present invention, and the description of the above embodiments is only used to help understand the method and core idea of ​​the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including manufacturing and using any device or system, and implementing any combination method. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, the present invention can also be improved and modified. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed by the present invention can be used in combination with each other in any way, and the exhaustive description of the situation of these combinations in this specification is only for the consideration of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A super-hydrophobic plant fiber agricultural film, characterized in that: The invention comprises the following raw materials: plant fiber substrate, alkyl ketene dimer wax powder, and super hydrophobic modified starch; Wherein, the super hydrophobic modified starch is prepared by the following steps: Step 1, p-formylphenylboronic acid, acetone, sodium hydroxide and ethanol solution are mixed in a container, stirred evenly, and reacted at room temperature for 1 hour to obtain intermediate 1; Step 2, starch and deionized water are mixed in a container, stirred evenly, and the system temperature is raised to 80°C under nitrogen protection. After gelatinization at 80°C for 1 hour, the system temperature is lowered to 60°C, and a dilute nitric acid solution of ammonium cerium nitrate is added to the container. After the addition is completed, an ethanol solution of the intermediate 1 is added dropwise to the container for 0.5 hours. After the addition is completed, the reaction is carried out at 60°C for 3 hours to obtain a grafted modified starch; Step 3: Mix the grafted modified starch, stearyl glycol and ethanol solution in a container, stir evenly, adjust the pH of the system to 9-10 with a 10% by mass sodium hydroxide aqueous solution, then raise the system temperature to 80°C under nitrogen protection, and stir the reaction at 80°C for 1 hour to obtain super hydrophobic modified starch.

2. A super-hydrophobic plant fiber agricultural film according to claim 1, characterized in that: The ethanol solution used in step 1 is an ethanol aqueous solution with a volume fraction of 95%, and the amount ratio of p-formylphenylboric acid, acetone, sodium hydroxide and ethanol solution used is 0.05 mol: 0.025 mol: 6-8 g: 30-40 mL.

3. A super-hydrophobic plant fiber agricultural film according to claim 1, characterized in that: The dilute nitric acid solution of ammonium cerium nitrate used in step 2 is prepared from 2.7g of ammonium cerium nitrate and 15mL of dilute nitric acid with a mass fraction of 10%, the ethanol solution of intermediate 1 used is prepared from 0.02mol of intermediate 2 and 30mL of anhydrous ethanol, and the amount ratio of starch, deionized water, dilute nitric acid solution of ammonium cerium nitrate and ethanol solution of intermediate 1 used is 30g:120-150mL:18.52g:30.1g.

4. A super-hydrophobic plant fiber agricultural film according to claim 1, characterized in that: The ethanol solution used in step 3 is an ethanol aqueous solution with a volume fraction of 10%, and the amount ratio of the grafted modified starch, stearyl glycol, and ethanol solution used is 30-35g: 0.06-0.1mol: 150-180mL.

5. A method for preparing a super-hydrophobic plant fiber agricultural film according to any one of claims 1 to 4, characterized in that: The following steps are involved: The first step is to heat and melt the alkyl ketene dimer wax powder, add it into a sodium hydroxide aqueous solution, and stir it at high speed to obtain an AKD emulsion; Step 2: adding super-hydrophobic modified starch to the AKD emulsion, and cooling the material with cold water after high-speed shear stirring to obtain a super-hydrophobic AKD emulsion; The third step is to coat the super-hydrophobic AKD emulsion on the surface of the plant fiber substrate and dry and solidify it to obtain a super-hydrophobic plant fiber agricultural film.

6. The method for preparing a super-hydrophobic plant fiber agricultural film according to claim 5, characterized in that: In the first step, the temperature at which the alkyl ketene dimer wax powder is heated is 65-75°C.

7. The method for preparing a super-hydrophobic plant fiber agricultural film according to claim 5, characterized in that: The temperature of the sodium hydroxide aqueous solution in the first step is 75° C. and the pH value is 8.5-9.

5.

8. The method for preparing a super-hydrophobic plant fiber agricultural film according to claim 5, characterized in that: In the first step, the rotation speed condition of the high-speed shear stirring is 3000-3600 rpm, and the time condition of the high-speed shear stirring is 3-4 minutes.

9. The method for preparing a super-hydrophobic plant fiber agricultural film according to claim 5, characterized in that: In the second step, the rotation speed condition of the high-speed shear stirring is 7600-8400 rpm, and the time condition of the high-speed shear stirring is 10-12 min.

10. The method for preparing a super-hydrophobic plant fiber agricultural film according to claim 5, characterized in that: Calculated by weight, the usage ratio of alkyl ketene dimer wax powder, sodium hydroxide aqueous solution and super hydrophobic modified starch is 1 part: 10-12 parts: 0.7-0.9 parts.