Agricultural film filler, double-layer agricultural functional film and preparation method of double-layer agricultural functional film

Abstract

The invention belongs to the technical field of agricultural products, and provides an agricultural film filler, a double-layer agricultural functional film and a preparation method of the double-layer agricultural functional film, and the agricultural film filler comprises the following components in parts by mass: 15-20 parts of modified silicon dioxide and 25-28 parts of a photochromic material. Silicon dioxide is subjected to carboxylation modification, carboxyl is a hydrophilic group, silicon dioxide has hydrophilicity, the modified silicon dioxide is added into the agricultural film, the hydrophilicity of the film can be improved, fog drops on the top in the agricultural film can rapidly flow down, the light transmittance of the agricultural film is kept, and meanwhile yellow leaves and epidemic diseases caused by the fact that water drops drip on seedlings are avoided. Spiropyrane and carboxyl carbon nanotubes are subjected to esterification reaction, spiropyrane and the carbon nanotubes are combined, the dispersion degree of the material is improved, and unreacted carboxyl also exists on the surfaces of the carbon nanotubes, so that the carbon nanotubes also have hydrophilicity.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural products, and in particular to an agricultural film filler and a double-layer agricultural functional film and a preparation method thereof. Background Art

[0002] Amidst the accelerating modernization of agriculture, agricultural films have become indispensable products for modern agricultural production due to their exceptional properties. Agricultural films significantly enhance low-temperature performance, retain moisture, transform soil nutrients, suppress weeds, and optimize soil microbial community structure. Agricultural films are primarily used in under-film transplanting techniques, where seedlings grow under the cover of film. During this growth process, sunny days and direct sunlight can cause the temperature under the film to rise sharply, impacting seedling growth. To mitigate this, color-changing agricultural films have been developed. These films change color under sunlight, blocking direct sunlight; in inclement weather, they transform into transparent films to enhance sunlight transmission. However, these color-changing films are produced by coating the film with color-changing materials, resulting in complex production processes and low production efficiency. Furthermore, to impart different functionalities to the film, different films must be laminated, leading to an increasing number of initial film layers, sometimes reaching seven, significantly increasing process requirements and costs. Therefore, developing a simple agricultural film with reversible color-changing properties has become a pressing issue in modern agriculture. Summary of the Invention

[0003] The purpose of the present invention is to overcome the defects in the prior art and provide an agricultural film filler and a double-layer agricultural functional film and a preparation method thereof.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides an agricultural film filler comprising the following components in parts by mass:

[0006] 15-20 parts of modified silicon dioxide, 25-28 parts of photochromic material.

[0007] Preferably, the preparation method of the modified silicon dioxide comprises the following steps:

[0008] Succinic anhydride, a silane coupling agent and N,N-dimethylformamide are mixed, and then silicon dioxide is added to react to obtain modified silicon dioxide.

[0009] Preferably, the usage ratio of succinic anhydride, silane coupling agent, N,N-dimethylformamide and silicon dioxide is 1-5 g: 1-5 g: 80-90 mL: 10-15 g;

[0010] The particle size of the silicon dioxide is 500 to 600 nm;

[0011] The mixing speed is 1000-1200 rpm and the mixing time is 1-2 hours;

[0012] The reaction time is 6 to 8 hours.

[0013] Preferably, the method for preparing the photochromic material comprises the following steps:

[0014] N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide are mixed, and then a catalyst solution is added to carry out an esterification reaction to obtain a photochromic material.

[0015] Preferably, the amount ratio of the N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide is 1-5 g: 10-20 g: 50-100 mL;

[0016] The catalyst solution is a dimethyl sulfoxide solution of 4-dimethylaminopyridine;

[0017] The mass concentration of the catalyst solution is 30-40%;

[0018] The amount ratio of the N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran and the catalyst solution is 1-5 g: 1-3 mL;

[0019] The mixing speed is 100-500 rpm and the mixing time is 0.5-1 h;

[0020] The temperature of the esterification reaction is 30-35° C., and the time is 16-24 hours.

[0021] The present invention also provides a double-layer agricultural functional film, which comprises an anti-aging layer and a reversible color-changing layer from top to bottom;

[0022] The agricultural film filler is added into the reversible color-changing layer.

[0023] Preferably, the thickness ratio of the anti-aging layer to the reversible color change layer is 1 to 1.5:1.

[0024] The present invention also provides a method for preparing the double-layer agricultural functional film, comprising the following steps:

[0025] (1) mixing polyethylene, polyvinylidene fluoride, a compatibilizer, a toughening agent and an anti-aging agent, extruding, and blow molding to obtain an anti-aging layer;

[0026] (2) mixing polyethylene, an inorganic filler, a compatibilizer, and the agricultural film filler, and performing extrusion and blow molding to obtain a reversible color-changing layer;

[0027] (3) The anti-aging layer and the reversible color-changing layer are stacked and then hot-pressed to obtain the double-layer agricultural functional film.

[0028] Preferably, in step (1), the mass ratio of polyethylene, polyvinylidene fluoride, compatibilizer, toughening agent and anti-aging agent is 40-50:20-25:1-5:1-5:1-5;

[0029] The melting temperature of the mixture in step (1) is 145-150° C., and the screw speed is 60-80 rpm;

[0030] The extrusion temperature in step (1) is 155-160°C;

[0031] The blow molding in step (1) has a blow ratio of 2.5 to 3:1 and a draw ratio of 4 to 6:1.

[0032] Preferably, in step (2), the mass ratio of polyethylene, inorganic filler, compatibilizer and the agricultural film filler according to any one of claims 1 to 5 is 40-50:1-5:1-5:5-8;

[0033] The melting temperature of the mixture in step (2) is 145-150° C., and the screw speed is 60-80 rpm;

[0034] The extrusion temperature in step (2) is 150-155°C;

[0035] The blow molding process in step (2) has a blow ratio of 2.5 to 3:1 and a draw ratio of 4 to 6:1;

[0036] The hot pressing temperature in step (3) is 80-90° C., the pressure is 3-4 MPa, and the holding time is 4-6 min.

[0037] The present invention provides an agricultural film filler comprising the following components by weight: 15-20 parts modified silica and 25-28 parts photochromic material. The modified silica is obtained by mixing succinic anhydride, a silane coupling agent, and N,N-dimethylformamide, and then adding the silica to react. The silica is carboxylated, and the carboxyl groups are hydrophilic groups, making the silica hydrophilic. Adding the modified silica to agricultural film improves the film's hydrophilicity, allowing mist droplets on the top of the film to flow down quickly. This maintains the film's light transmittance while preventing yellowing leaves and blight caused by water droplets dripping onto seedlings. The present invention mixes N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide, and then adds a catalyst solution to carry out an esterification reaction to obtain a photochromic material. The spiropyran has the ability of reversible photochromism, but will agglomerate when directly used. In this case, the present invention carries out an esterification reaction between the spiropyran and the carboxyl carbon nanotubes, and combines the spiropyran with the carbon nanotubes, thereby improving the dispersion of the material. In addition, there are unreacted carboxyl groups on the surface of the carbon nanotubes, which can also improve the hydrophilicity.

[0038] The present invention uses the prepared agricultural film filler directly as the initial filler for agricultural film processing. The resulting agricultural film not only exhibits reversible photochromic properties but also exhibits excellent hydrophilicity, preventing the formation of water mist. The present invention's double-layer agricultural functional film is simple to prepare, eliminating the need for photochromic coating. Furthermore, by combining photochromic and hydrophilic properties into a single film, the film's structure is significantly simplified, improving production efficiency. DETAILED DESCRIPTION

[0039] The present invention provides an agricultural film filler comprising the following components in parts by mass:

[0040] 15-20 parts of modified silicon dioxide, 25-28 parts of photochromic material.

[0041] In the present invention, the mass fraction of the modified silica is preferably 16 to 19 parts, more preferably 16.5 to 18.5 parts, and even more preferably 17 to 18 parts.

[0042] In the present invention, the mass fraction of the photochromic material is preferably 25.5 to 27.5 parts, more preferably 26 to 27 parts, and even more preferably 26.4 to 26.6 parts.

[0043] In the present invention, the preparation method of the modified silica comprises the following steps:

[0044] Succinic anhydride, a silane coupling agent and N,N-dimethylformamide are mixed, and then silicon dioxide is added to react to obtain modified silicon dioxide.

[0045] In the present invention, the usage ratio of succinic anhydride, silane coupling agent, N,N-dimethylformamide and silica is preferably 1-5 g: 1-5 g: 80-90 mL: 10-15 g, more preferably 2-4 g: 2-4 g: 82-88 mL: 11-14 g, and more preferably 2.5-3 g: 2.5-3 g: 84-86 mL: 12-13 g.

[0046] In the present invention, the particle size of the silicon dioxide is preferably 500 to 600 nm, more preferably 520 to 580 nm, and even more preferably 540 to 560 nm.

[0047] In the present invention, the silane coupling agent is KH550.

[0048] In the present invention, the mixing speed is preferably 1000-1200 rpm, more preferably 1050-1150 rpm, more preferably 1080-1120 rpm; the mixing time is preferably 1-2 h, more preferably 1.2-1.8 h, more preferably 1.4-1.6 h.

[0049] In the present invention, the reaction time is preferably 6 to 8 hours, more preferably 6.5 to 7.5 hours, and even more preferably 6.8 to 7.2 hours.

[0050] In the present invention, the method for preparing the photochromic material comprises the following steps:

[0051] N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide are mixed, and then a catalyst solution is added to carry out an esterification reaction to obtain a photochromic material.

[0052] In the present invention, the usage ratio of the N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide is preferably 1-5 g:10-20 g:50-100 mL, more preferably 2-4 g:12-18 g:60-90 mL, and more preferably 2.5-3 g:14-16 g:70-80 mL.

[0053] In the present invention, the catalyst solution is a dimethyl sulfoxide solution of 4-dimethylaminopyridine.

[0054] In the present invention, the mass concentration of the catalyst solution is preferably 30-40%, more preferably 32-38%, and even more preferably 34-36%.

[0055] In the present invention, the usage ratio of the N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran and the catalyst solution is preferably 1-5 g:1-3 mL, more preferably 2-4 g:1.5-2.5 mL, and more preferably 2.5-3 g:1.8-2 mL.

[0056] In the present invention, the mixing speed is preferably 100-500 rpm, more preferably 200-400 rpm, more preferably 300-350 rpm; the mixing time is preferably 0.5-1 h, more preferably 0.6-0.9 h, more preferably 0.7-0.8 h.

[0057] In the present invention, the temperature of the esterification reaction is preferably 30-35° C., more preferably 31-34° C., more preferably 32-33° C.; the time is preferably 16-24 h, more preferably 18-22 h, more preferably 19-20 h.

[0058] In the present invention, after the esterification reaction is completed, the reaction is filtered, and the dimethyl sulfoxide is removed by distillation under reduced pressure. Anhydrous methanol is used for precipitation, filtration and drying to obtain the photochromic material.

[0059] The present invention also provides a double-layer agricultural functional film, which comprises an anti-aging layer and a reversible color-changing layer from top to bottom;

[0060] The agricultural film filler is added into the reversible color-changing layer.

[0061] In the present invention, the thickness ratio of the anti-aging layer to the reversible color change layer is preferably 1 to 1.5:1, more preferably 1.1 to 1.4:1, and even more preferably 1.2 to 1.3:1.

[0062] The present invention also provides a method for preparing the double-layer agricultural functional film, comprising the following steps:

[0063] (1) mixing polyethylene, polyvinylidene fluoride, a compatibilizer, a toughening agent and an anti-aging agent, extruding, and blow molding to obtain an anti-aging layer;

[0064] (2) mixing polyethylene, an inorganic filler, a compatibilizer, and the agricultural film filler according to any one of claims 1 to 5, and performing extrusion and blow molding to obtain a reversible color-changing layer;

[0065] (3) The anti-aging layer and the reversible color-changing layer are stacked and then hot-pressed to obtain the double-layer agricultural functional film.

[0066] In the present invention, the mass ratio of polyethylene, polyvinylidene fluoride, compatibilizer, toughening agent and anti-aging agent in step (1) is preferably 40-50:20-25:1-5:1-5:1-5, more preferably 42-48:21-24:1.5-4.5:1.5-4.5:1.5-4.5, and more preferably 44-46:22-23:2-4:2-4:2-4.

[0067] In the present invention, the compatibilizer is one or more of dibutyl phthalate, diisononyl phthalate and triphenyl phosphite.

[0068] In the present invention, the toughening agent is a polyolefin elastomer and / or an ethylene-vinyl acetate copolymer.

[0069] In the present invention, the anti-aging agent is one or more of UV-9, UV-327, antioxidant 1010 and antioxidant 1076.

[0070] In the present invention, the melting temperature of the mixture in step (1) is preferably 145-150°C, more preferably 146-149°C, and more preferably 147-148°C; the screw speed is preferably 60-80 rpm, more preferably 65-75 rpm, and more preferably 68-70 rpm.

[0071] In the present invention, the extrusion temperature in step (1) is preferably 155-160°C, more preferably 156-159°C, and even more preferably 157-158°C.

[0072] In the present invention, the blow ratio of the blow molding in step (1) is preferably 2.5-3:1, more preferably 2.6-2.9:1, more preferably 2.7-2.8:1; the pulling ratio is preferably 4-6:1, more preferably 4.5-5.5:1, more preferably 4.8-5.2:1.

[0073] In the present invention, the mass ratio of polyethylene, inorganic filler, compatibilizer and agricultural film filler in step (2) is preferably 40-50:1-5:1-5:5-8, more preferably 42-48:1.5-4.5:1.5-4.5:5.5-7.5, and more preferably 44-46:2-4:2-4:6-7.

[0074] In the present invention, the inorganic filler includes one or more of calcium carbonate, magnesium sulfate, talc, potassium sulfate, and mica powder.

[0075] In the present invention, the compatibilizer is one or more of dibutyl phthalate, diisononyl phthalate and triphenyl phosphite.

[0076] In the present invention, the melting temperature of the mixture in step (2) is preferably 145-150°C, more preferably 146-149°C, and more preferably 147-148°C; the screw speed is preferably 60-80 rpm, more preferably 65-75 rpm, and more preferably 68-70 rpm.

[0077] In the present invention, the extrusion temperature in step (2) is preferably 150-155°C, more preferably 151-154°C, and even more preferably 152-153°C.

[0078] In the present invention, the blow ratio of the blow molding in step (2) is preferably 2.5-3:1, more preferably 2.6-2.9:1, more preferably 2.7-2.8:1; the pulling ratio is preferably 4-6:1, more preferably 4.5-5.5:1, more preferably 4.8-5.2:1.

[0079] In the present invention, the temperature of the hot pressing in step (3) is preferably 80-90°C, more preferably 82-88°C, and more preferably 84-86°C; the pressure is preferably 3-4 MPa, more preferably 3.2-3.8 MPa, and more preferably 3.4-3.6 MPa; and the holding time is preferably 4-6 min, more preferably 4.5-5.5 min, and more preferably 4.8-5.2 min.

[0080] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0081] Example 1

[0082] Preparation of modified silica:

[0083] 3 g of succinic anhydride, 2 g of silane coupling agent KH550 and 85 mL of N,N-dimethylformamide were mixed and stirred at 1100 rpm for 1.5 h. Then, 12 g of silica (particle size 550 nm) was added and the reaction was continued at the same speed for 7 h to obtain modified silica.

[0084] Preparation of photochromic materials:

[0085] 4 g of N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, 18 g of carboxyl carbon nanotubes and 60 mL of dimethyl sulfoxide were mixed and stirred at 400 rpm for 0.8 h. The speed was kept constant, and 3 mL of a 35% mass concentration of 4-dimethylaminopyridine in dimethyl sulfoxide solution was added. The speed was kept constant and the mixture was reacted at 32° C. for 20 h. After the reaction was completed, the mixture was filtered and the dimethyl sulfoxide was removed by vacuum distillation. The mixture was precipitated with anhydrous methanol, filtered and dried to obtain a photochromic material.

[0086] Take 18 parts of modified silica and 25 parts of photochromic material to obtain agricultural film filler.

[0087] Preparation of double-layer agricultural functional film:

[0088] Polyethylene, polyvinylidene fluoride, dibutyl phthalate, polyolefin elastomer and UV-9 are mixed in a mass ratio of 45:23:3:2:1, the melting temperature of the mixture is 145°C, and the screw speed is 70 rpm; then the extrusion temperature is controlled to be 158°C for extrusion, and the blowing ratio is controlled to be 2.8:1 and the pulling ratio is controlled to be 5:1 for blow molding to obtain an anti-aging layer.

[0089] Polyethylene, talc, dibutyl phthalate and the above-mentioned agricultural film filler are mixed in a mass ratio of 45:1:2:6, with a melting temperature of 150°C and a rotation speed of 70 rpm; then, the extrusion temperature is controlled to be 155°C, and blow molding is performed at a blowing ratio of 2.8:1 and a pulling ratio of 5:1 to obtain a reversible color-changing layer.

[0090] The thickness ratio of the anti-aging layer and the reversible color-changing layer was controlled to be 1:1. After being neatly stacked, the double-layer agricultural functional film was obtained by maintaining the pressure at 85°C and 3.5 MPa for 5 minutes.

[0091] Example 2

[0092] Preparation of modified silica:

[0093] 5 g of succinic anhydride, 1 g of silane coupling agent KH550 and 90 mL of N,N-dimethylformamide were mixed and stirred at 1000 rpm for 1 h. Then, 10 g of silica (particle size 540 nm) was added and the reaction was continued at the same speed for 6.5 h to obtain modified silica.

[0094] Preparation of photochromic materials:

[0095] 3 g of N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, 12 g of carboxyl carbon nanotubes and 70 mL of dimethyl sulfoxide were mixed and stirred at 300 rpm for 1 hour. The speed was kept constant, and 2 mL of a 30% mass concentration of 4-dimethylaminopyridine in dimethyl sulfoxide solution was added. The speed was kept constant and the mixture was reacted at 32° C. for 18 hours. After the reaction was completed, the mixture was filtered and the dimethyl sulfoxide was removed by vacuum distillation. The mixture was precipitated with anhydrous methanol, filtered and dried to obtain a photochromic material.

[0096] 16 parts of modified silica and 27 parts of photochromic material are taken to obtain agricultural film filler.

[0097] Preparation of double-layer agricultural functional film:

[0098] Polyethylene, polyvinylidene fluoride, diisononyl phthalate, ethylene-vinyl acetate copolymer and UV-327 are mixed in a mass ratio of 42:26:2:2:2, the melting temperature of the mixture is 148°C, and the screw speed is 70rpm; then the extrusion temperature is controlled to be 156°C for extrusion, and the blowing ratio is controlled to be 3:1 and the pulling ratio is controlled to be 4:1 for blow molding to obtain an anti-aging layer.

[0099] Polyethylene, mica powder, diisononyl phthalate and the above-mentioned agricultural film filler are mixed in a mass ratio of 48:5:4:8, with a melting temperature of 146°C and a rotation speed of 70 rpm. Then, the extrusion temperature is controlled to be 152°C, and blow molding is performed at a blowing ratio of 2.6:1 and a pulling ratio of 4:1 to obtain a reversible color-changing layer.

[0100] The thickness ratio of the anti-aging layer and the reversible color-changing layer was controlled to be 1.3:1. After being neatly stacked, the double-layer agricultural functional film was obtained by maintaining the pressure at 80°C and 4 MPa for 4 minutes.

[0101] Example 3

[0102] Preparation of modified silica:

[0103] 2 g of succinic anhydride, 1 g of silane coupling agent KH550 and 80 mL of N,N-dimethylformamide were mixed and stirred at 1000 rpm for 2 h. Then, 14 g of silica (particle size 600 nm) was added and the reaction was carried out at the same speed for 8 h to obtain modified silica.

[0104] Preparation of photochromic materials:

[0105] 5 g of N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, 18 g of carboxyl carbon nanotubes and 90 mL of dimethyl sulfoxide were mixed and stirred at 500 rpm for 1 hour. The speed was kept constant, and 3 mL of a dimethyl sulfoxide solution of 4-dimethylaminopyridine with a mass concentration of 40% was added. The speed was kept constant and the mixture was reacted at 35° C. for 23 hours. After the reaction was completed, the mixture was filtered and the dimethyl sulfoxide was removed by vacuum distillation. The mixture was precipitated with anhydrous methanol, filtered and dried to obtain a photochromic material.

[0106] Take 20 parts of modified silica and 25 parts of photochromic material to obtain agricultural film filler.

[0107] Preparation of double-layer agricultural functional film:

[0108] Polyethylene, polyvinylidene fluoride, triphenyl phosphite, ethylene-vinyl acetate copolymer and antioxidant 1010 are mixed in a mass ratio of 50:21:4:2:5, the melting temperature of the mixture is 150°C, and the screw speed is 80 rpm; then, the extrusion temperature is controlled to be 160°C for extrusion, and the blowing ratio is controlled to be 2.6:1 and the pulling ratio is controlled to be 5:1 for blow molding to obtain an anti-aging layer.

[0109] Polyethylene, potassium sulfate, diisononyl phthalate and the above-mentioned agricultural film filler are mixed in a mass ratio of 41:2:5:7, with a melting temperature of 150°C and a rotation speed of 60 rpm; then the extrusion temperature is controlled to be 150°C, and blow molding is performed at a blowing ratio of 3:1 and a pulling ratio of 5:1 to obtain a reversible color-changing layer.

[0110] The thickness ratio of the anti-aging layer and the reversible color-changing layer was controlled to be 1.5:1. After being neatly stacked, the double-layer agricultural functional film was obtained by maintaining the pressure at 88°C and 3.5MPa for 6 minutes.

[0111] The double-layer agricultural functional films prepared in Examples 1 to 3 were subjected to performance tests.

[0112] The ordinary mulch film in the control group was purchased from Shandong Changhao Plastic Industry Co., Ltd., and the base resin was polyethylene.

[0113] Before ultraviolet light irradiation, the corresponding transmittance was recorded using an ocean spectrometer. -2 After irradiation with 365nm ultraviolet light for 1 minute, the relevant transmittance data were recorded using an ocean spectrometer. 350nm was taken as the reference wavelength point to compare the transmittance data. The test results are shown in Table 1.

[0114] Table 1 Transmittance test results

[0115] Sample number Ordinary mulch Example 1 Example 2 Example 3 <![CDATA[Incident light intensity I0 / lux]]> 1000 1000 1000 1000 <![CDATA[Light intensity I through the membrane t / lux]]> 1000 921.6 910.7 915.3

[0116] The double-layer agricultural functional films and ordinary ground films prepared in Examples 1 to 3 were subjected to performance tests, wherein the film thickness and tensile performance tests were performed with reference to GB13735-2017 “Polyethylene Blown Agricultural Ground Covering Film”. The test results are shown in Table 2.

[0117] Table 2 Tensile properties test results

[0118] Sample number Ordinary mulch Example 1 Example 2 Example 3 Tensile strength σ / MPa 23.45 32.67 33.41 33.18 Load / Mpa 2 10 10 10 Elongation / % 115.32 314.52 320.63 318.76

[0119] Examples 1 to 3 were subjected to UV resistance and haze tests using an ultraviolet light blocking tester, i.e., a solar film tester, which emits light containing the ultraviolet spectrum. After passing through the film to be tested, the instrument detects the intensity of the ultraviolet light after transmission and automatically calculates the blocking rate. The haze test was performed in accordance with GB / T2410-2008, and the results are recorded in Table 3.

[0120] Table 3 Anti-ultraviolet performance and haze test results

[0121] Sample number Ordinary mulch Example 1 Example 2 Example 3 Transmittance / % 100 68.47 69.32 63.44 UV blocking rate / % 0 76.72 81.06 75.31 Color change performance none have have have Haze (%) 18.7 10.1 11.4 11.8

[0122] As demonstrated in the above examples, the present invention provides agricultural film fillers that can be directly used as initial fillers for agricultural film processing. The resulting agricultural film not only exhibits reversible photochromic properties but also exhibits excellent hydrophilicity, preventing the formation of mist. The present invention's dual-layer agricultural functional film is simple to prepare, eliminating the need for photochromic coating. Furthermore, by combining photochromic and hydrophilic properties into a single film, the film's structure is significantly simplified, improving production efficiency.

[0123] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An agricultural film filler, characterized in that: Contains the following components in parts by mass: 15-20 parts of modified silicon dioxide, 25-28 parts of photochromic material.

2. The agricultural film filler according to claim 1, characterized in that: The preparation method of the modified silicon dioxide comprises the following steps: Succinic anhydride, a silane coupling agent and N,N-dimethylformamide are mixed, and then silicon dioxide is added to react to obtain modified silicon dioxide.

3. The agricultural film filler according to claim 2, characterized in that: The usage ratio of succinic anhydride, silane coupling agent, N,N-dimethylformamide and silicon dioxide is 1-5g:1-5g:80-90mL:10-15g; The particle size of the silicon dioxide is 500 to 600 nm; The mixing speed is 1000-1200 rpm and the mixing time is 1-2 hours; The reaction time is 6 to 8 hours.

4. The agricultural film filler according to claim 1, characterized in that: The preparation method of the photochromic material comprises the following steps: N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide are mixed, and then a catalyst solution is added to carry out an esterification reaction to obtain a photochromic material.

5. The agricultural film filler according to claim 4, characterized in that: The amount ratio of the N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran, carboxyl carbon nanotubes and dimethyl sulfoxide is 1-5 g: 10-20 g: 50-100 mL; The catalyst solution is a dimethyl sulfoxide solution of 4-dimethylaminopyridine; The mass concentration of the catalyst solution is 30-40%; The amount ratio of the N-hydroxyethyl-3,3-dimethyl-6-nitroindoline spiropyran and the catalyst solution is 1-5 g: 1-3 mL; The mixing speed is 100-500 rpm and the mixing time is 0.5-1 h; The temperature of the esterification reaction is 30-35° C., and the time is 16-24 hours.

6. A double-layer agricultural functional film, characterized in that: From top to bottom, there are the anti-aging layer and the reversible color-changing layer; The agricultural film filler according to any one of claims 1 to 5 is added to the reversible color-changing layer.

7. The double-layer agricultural functional film according to claim 6, characterized in that: The thickness ratio of the anti-aging layer to the reversible color change layer is 1 to 1.5:

1.

8. The method for preparing the double-layer agricultural functional film according to claim 6 or 7, characterized in that: It includes the following steps: (1) mixing polyethylene, polyvinylidene fluoride, a compatibilizer, a toughening agent and an anti-aging agent, extruding, and blow molding to obtain an anti-aging layer; (2) mixing polyethylene, an inorganic filler, a compatibilizer, and the agricultural film filler according to any one of claims 1 to 5, and performing extrusion and blow molding to obtain a reversible color-changing layer; (3) The anti-aging layer and the reversible color-changing layer are stacked and then hot-pressed to obtain the double-layer agricultural functional film.

9. The method for preparing a double-layer agricultural functional film according to claim 8, wherein: In step (1), the mass ratio of polyethylene, polyvinylidene fluoride, compatibilizer, toughening agent and anti-aging agent is 40-50:20-25:1-5:1-5:1-5; The melting temperature of the mixture in step (1) is 145-150° C., and the screw speed is 60-80 rpm; The extrusion temperature in step (1) is 155-160°C; The blow molding in step (1) has a blow ratio of 2.5 to 3:1 and a draw ratio of 4 to 6:

1.

10. The method for preparing a double-layer agricultural functional film according to claim 8 or 9, characterized in that: In step (2), the mass ratio of polyethylene, inorganic filler, compatibilizer and the agricultural film filler according to any one of claims 1 to 5 is 40-50:1-5:1-5:5-8; The melting temperature of the mixture in step (2) is 145-150° C., and the screw speed is 60-80 rpm; The extrusion temperature in step (2) is 150-155°C; The blow molding process in step (2) has a blow ratio of 2.5 to 3:1 and a draw ratio of 4 to 6:1; The hot pressing temperature in step (3) is 80-90° C., the pressure is 3-4 MPa, and the holding time is 4-6 min.