Reversible optically variable pigment master batch, agricultural functional film and preparation method of agricultural functional film

Abstract

The invention belongs to the technical field of agricultural films, and discloses a reversible light-variable pigment master batch, an agricultural functional film and a preparation method of the agricultural functional film. The reversible optically variable pigment master batch comprises the following components in parts by weight: 100 parts of resin, 10-30 parts of nano tungsten oxide microcapsules, 5-10 parts of dispersing aid, 1-5 parts of antioxidant, 1-10 parts of pigment and 5-20 parts of filler. The photochromic material is dispersed in a resin system in the form of microcapsules, so that the dispersity and compatibility of the photochromic material are improved, thermal stress is buffered, water and oxygen erosion is blocked, the service life of the photochromic material is prolonged, the thermal stability is improved, and the processability is improved. The color of the agricultural functional film composed of the reversible light-variable pigment master batch is darkened under the irradiation of ultraviolet light; after ultraviolet light is removed, the color of the film disappears, and the film has good photochromic performance and reversibly changes color along with illumination change.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of agricultural film, in particular to a reversible photochromic pigment master batch and an agricultural functional film and a preparation method thereof. BACKGROUND

[0002] Modern greenhouse needs to be shaded and cooled during strong light period (for example, the intensity of ultraviolet light in summer noon > 100 W / m 2 ) to avoid light saturation damage to crops. At present, it mainly depends on physical shading net (light shielding rate 40-70%) and spray cooling, but the physical shading net needs to be repeatedly collected and placed according to the weather every day, which increases the labor cost and the time of placing the shading net (for example, it takes about 30 minutes to place the shading net when the greenhouse area is large), which may cause instantaneous high temperature burn of crops; the spray cooling system consumes a large amount of water and needs power supply, which increases the energy consumption.

[0003] With the deepening of research, researchers have proposed photochromic film, but the core variable color materials such as spiropyrans and azobenzenes have defects such as poor weather resistance (the variable color ability is attenuated by more than 60% after 500h of ultraviolet irradiation), low thermal stability (the decomposition rate increases when the processing temperature exceeds 160℃, which cannot be compatible with the film blowing process), and insufficient service life (failure occurs after 6-8 months of field use, which cannot meet the use standard of agricultural film), which limits the wide application of photochromic film in agricultural film.

[0004] Therefore, it is an urgent problem to develop a photochromic agricultural film with high weather resistance, precise light response and processing compatibility. SUMMARY

[0005] The present application aims to provide a reversible photochromic pigment master batch and an agricultural functional film and a preparation method thereof, which solves the problems of poor weather resistance, low thermal stability and insufficient service life of the existing photochromic film used in agricultural film.

[0006] In order to achieve the above-mentioned application purpose, the present application provides the following technical scheme:

[0007] The present application provides a reversible photochromic pigment master batch, which comprises the following raw materials in mass fraction: resin 100 parts, nano tungsten oxide microcapsule 10-30 parts, dispersion aid 5-10 parts, antioxidant 1-5 parts, pigment 1-10 parts, and filler 5-20 parts.

[0008] Preferably, in the above-mentioned reversible photochromic pigment master batch, the resin is one or more of polyethylene, polypropylene, poly-1-butene and ethylene-vinyl acetate copolymer.

[0009] Preferably, in the above-mentioned reversible photochromic pigment master batch, the dispersing aid is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and styrene-maleic anhydride copolymer.

[0010] Preferably, in the above-mentioned reversible photochromic pigment master batch, the antioxidant is antioxidant 1010 and / or antioxidant 168.

[0011] Preferably, in the above-mentioned reversible photochromic pigment master batch, the preparation method of the nano tungsten oxide microcapsule comprises the following steps:

[0012] Mixing nano tungsten oxide, dispersing agent, initiator, and liquid paraffin to obtain an oil phase;

[0013] Mixing a surfactant, methyl methacrylate, and water to obtain an aqueous phase;

[0014] Emulsifying the oil phase in the aqueous phase to obtain an emulsion;

[0015] Heating the emulsion to perform a polymerization reaction to obtain nano tungsten oxide coated with a first shell layer;

[0016] Mixing nano tungsten oxide coated with a first shell layer, tetraethyl orthosilicate, water, anhydrous ethanol, and ammonia water to perform a reaction to obtain nano tungsten oxide coated with a second shell layer, i.e., the nano tungsten oxide microcapsule.

[0017] Preferably, in the above-mentioned reversible photochromic pigment master batch, the particle size of the nano tungsten oxide is 30-100 nm.

[0018] Preferably, in the above-mentioned reversible photochromic pigment master batch, the use amount ratio of the nano tungsten oxide, dispersing agent, initiator, and liquid paraffin is 5-10 g: 1-8 g: 1-10 g: 100 mL; the use amount ratio of the surfactant, methyl methacrylate, and water is 0.1-1 g: 5-10 g: 100 mL; and the use amount ratio of the nano tungsten oxide coated with a first shell layer, tetraethyl orthosilicate, water, anhydrous ethanol, and ammonia water is 1-5 g: 10-20 mL: 100-200 mL: 100-200 mL: 50-150 mL.

[0019] Preferably, in the above-mentioned reversible photochromic pigment master batch, the emulsification time is 10-30 min; the polymerization reaction temperature is 70-90℃; the polymerization reaction time is 2-5 h; the reaction temperature is 25-40℃; and the reaction time is 1-3 h.

[0020] The application further provides a preparation method of the reversible photochromic pigment master batch, comprising the following steps:

[0021] The resin, nano tungsten oxide microcapsule, dispersing aid, antioxidant, pigment and filler are mixed to obtain a mixture;

[0022] The mixture is extruded and granulated in a double screw extruder to obtain the reversible photochromic pigment master batch.

[0023] The application further provides an agricultural functional film comprising the reversible photochromic film layer.

[0024] The reversible photochromic film layer comprises the following raw materials in mass fraction: 100 parts of base resin, 5-30 parts of reversible photochromic pigment master batch.

[0025] The reversible photochromic pigment master batch is the above-mentioned reversible photochromic pigment master batch.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] (1) The reversible photochromic material is dispersed in the resin system in the form of microcapsule, so that the dispersibility and compatibility of the reversible photochromic material are improved, the capsule wall of the microcapsule also protects the reversible photochromic core material, buffers thermal stress and blocks water and oxygen erosion, prolongs the service life of the reversible photochromic material, improves the thermal stability and improves the processing performance.

[0028] (2) The agricultural functional film composed of the reversible photochromic pigment master batch has the following effects: under ultraviolet irradiation, the transmittance of the agricultural film to visible light and near-infrared light decreases, the color of the film becomes darker; after the ultraviolet light is removed, the color of the film disappears, the agricultural film has good photochromic performance, can reversibly change color with light, and has fast color change rate and high color change stability.

[0029] (3) The preparation method of the reversible photochromic pigment master batch and the agricultural functional film is simple, has strong operability and is easy to be industrialized and mass-produced. DETAILED DESCRIPTION

[0030] The application provides a reversible photochromic pigment master batch comprising the following raw materials in mass fraction: 100 parts of resin, 10-30 parts of nano tungsten oxide microcapsule, 5-10 parts of dispersing aid, 1-5 parts of antioxidant, 1-10 parts of pigment and 5-20 parts of filler.

[0031] In the application, the mass fraction of the nano tungsten oxide microcapsule is preferably 15-27 parts, further preferably 20-26 parts and more preferably 25 parts.

[0032] In the application, the mass fraction of the dispersing aid is preferably 6-10 parts, further preferably 7-9 parts and more preferably 8 parts.

[0033] In the present application, the mass fraction of the antioxidant is preferably 1-4 parts, further preferably 2-4 parts, and more preferably 3 parts.

[0034] In the present application, the mass fraction of the pigment is preferably 3-9 parts, further preferably 5-8 parts, and more preferably 7 parts.

[0035] In the present application, the mass fraction of the filler is preferably 10-20 parts, further preferably 15-20 parts, and more preferably 20 parts.

[0036] In the present application, the resin is preferably one or more of polyethylene, polypropylene, poly-1-butene, and ethylene-vinyl acetate copolymer, further preferably one or more of polyethylene, polypropylene, and poly-1-butene, and more preferably a mixture of polyethylene and polypropylene.

[0037] In the present application, the dispersing aid is preferably one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and styrene-maleic anhydride copolymer, further preferably maleic anhydride grafted polyethylene or maleic anhydride grafted polypropylene, and more preferably maleic anhydride grafted polyethylene.

[0038] In the present application, the antioxidant is preferably antioxidant 1010 and / or antioxidant 168, further preferably antioxidant 1010 or antioxidant 168, and more preferably antioxidant 1010.

[0039] In the present application, the pigment is preferably one or more of titanium dioxide, zinc oxide, and carbon black, further preferably titanium dioxide or carbon black, and more preferably carbon black.

[0040] In the present application, the filler is preferably one or more of calcium carbonate, magnesium sulfate, talc powder, potassium sulfate, and mica powder, further preferably one or more of calcium carbonate, talc powder, and mica powder, and more preferably a mixture of calcium carbonate and mica powder.

[0041] In the present application, the preparation method of the nano tungsten oxide microcapsule comprises the following steps:

[0042] Mixing nano tungsten oxide, a dispersing agent, an initiator, and liquid paraffin to obtain an oil phase;

[0043] Mixing a surfactant, methyl methacrylate, and water to obtain an aqueous phase;

[0044] Emulsifying the oil phase into the aqueous phase to obtain an emulsion;

[0045] Heating the emulsion to perform a polymerization reaction to obtain nano tungsten oxide coated with a first shell layer;

[0046] The nano tungsten oxide coated with a first shell layer, tetraethyl orthosilicate, water, anhydrous ethanol and ammonia are mixed to react, so as to obtain nano tungsten oxide coated with a second shell layer, namely the nano tungsten oxide microcapsule.

[0047] In the present application, the particle size of the nano tungsten oxide is preferably 30-100 nm, further preferably 40-80 nm, and more preferably 50 nm.

[0048] In the present application, the dispersant is preferably alkyl phenol polyoxyethylene ether or Tween 80, and further preferably Tween 80.

[0049] In the present application, the initiator is preferably one or more of azobisisobutyronitrile, potassium persulfate and peroxobenzoyl, and further preferably azobisisobutyronitrile or potassium persulfate, and more preferably azobisisobutyronitrile.

[0050] In the present application, the surfactant is preferably sodium dodecyl sulfate and / or cetyltrimethylammonium bromide, and further preferably sodium dodecyl sulfate or cetyltrimethylammonium bromide, and more preferably sodium dodecyl sulfate.

[0051] In the present application, the ratio of the nano tungsten oxide, the dispersant, the initiator and the liquid paraffin is preferably 5-10 g: 1-8 g: 1-10 g: 100 mL, further preferably 6-9 g: 2-5 g: 1-5 g: 100 mL, and more preferably 7 g: 3 g: 2 g: 100 mL.

[0052] In the present application, the ratio of the surfactant, methyl methacrylate and water is preferably 0.1-1 g: 5-10 g: 100 mL, further preferably 0.3-0.8 g: 6-9 g: 100 mL, and more preferably 0.5 g: 8 g: 100 mL.

[0053] In the present application, the volume ratio of the oil phase and the water phase is preferably 1-2: 1, further preferably 1.5-2: 1, and more preferably 2: 1.

[0054] In the present application, the ratio of the nano tungsten oxide coated with a first shell layer, tetraethyl orthosilicate, water, anhydrous ethanol and ammonia is preferably 1-5 g: 10-20 mL: 100-200 mL: 100-200 mL: 50-150 mL, further preferably 2-5 g: 12-15 mL: 100-150 mL: 100-150 mL: 70-120 mL, and more preferably 4 g: 12 mL: 100 mL: 100 mL: 80 mL.

[0055] In the present application, the concentration of the ammonia is preferably 25-28%, further preferably 26-28%, and more preferably 27%.

[0056] In the present application, the emulsifying time is preferably 10-30 min, further preferably 15-25 min, and more preferably 20 min.

[0057] In the present application, the polymerization temperature is preferably 70-90℃, further preferably 75-90℃, and more preferably 80℃; the polymerization time is preferably 2-5h, further preferably 2-4h, and more preferably 3h.

[0058] In the present application, the reaction temperature is preferably 25-40℃, further preferably 25-35℃, and more preferably 30℃; the reaction time is preferably 1-3h, further preferably 1.5-3h, and more preferably 2h.

[0059] The present application also provides a preparation method of the reversible photo-variable pigment master batch, comprising the following steps:

[0060] The resin, nano tungsten oxide microcapsule, dispersing aid, antioxidant, pigment, and filler are mixed to obtain a mixture;

[0061] The mixture is extruded and granulated in a twin-screw extruder to obtain the reversible photo-variable pigment master batch.

[0062] In the present application, the extrusion and granulation temperature is preferably 200-220℃, further preferably 200-210℃, and more preferably 200℃.

[0063] The present application also provides an agricultural functional film, comprising a reversible photo-variable color film layer.

[0064] The reversible photo-variable color film layer comprises the following raw materials in mass fraction: 100 parts of base resin and 5-30 parts of reversible photo-variable pigment master batch.

[0065] The reversible photo-variable pigment master batch is the above-mentioned reversible photo-variable pigment master batch.

[0066] In the present application, the mass fraction of the reversible photo-variable pigment master batch is preferably 10-29 parts, further preferably 20-29 parts, and more preferably 28 parts.

[0067] In the present application, the base resin is preferably one or more of polyethylene, polypropylene, poly-1-butene, and ethylene-vinyl acetate copolymer, further preferably polyethylene or polypropylene, and more preferably polyethylene.

[0068] In the present application, the thickness of the reversible photo-variable color film layer is preferably 30-100μm, further preferably 35-60μm, and more preferably 40μm.

[0069] The present application also provides a preparation method of the agricultural functional film, comprising the following steps:

[0070] The base resin and the reversible photochromic pigment master batch are mixed, extruded and granulated by a double screw extruder, and then blown into a film by a film blowing machine to obtain the agricultural functional film.

[0071] In the present application, the temperature for the extrusion granulation is preferably 180-200°C, further preferably 190-200°C, and more preferably 200°C.

[0072] In the present application, the temperature for the film blowing is preferably 150-200°C, further preferably 150-180°C, and more preferably 160°C.

[0073] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0074] Embodiment 1

[0075] The reversible photochromic pigment master batch comprises the following raw materials in mass fraction: 80 parts of LDPE (molecular weight 150,000), 20 parts of polypropylene (molecular weight 100,000), 25 parts of nano tungsten oxide microcapsules, 8 parts of maleic anhydride grafted polyethylene, 10 parts of antioxidant 1010, 7 parts of carbon black, 15 parts of calcium carbonate, and 5 parts of mica powder.

[0076] The preparation method of the reversible photochromic pigment master batch comprises the following steps:

[0077] (1) Nano tungsten oxide (particle size 50 nm), Tween 80, azobis isobutyronitrile and liquid paraffin are uniformly mixed in a ratio of 7 g:3 g:2 g:100 mL to obtain an oil phase; sodium dodecyl sulfate, methyl methacrylate and water are uniformly mixed in a ratio of 0.5 g:8 g:100 mL to obtain an aqueous phase; the oil phase is added to the aqueous phase in a volume ratio of 2:1 and emulsified for 20 min to obtain an emulsion; the emulsion is heated to 80°C for polymerization reaction for 3 h to obtain nano tungsten oxide coated with a first shell layer; the nano tungsten oxide coated with the first shell layer, water, anhydrous ethanol and ammonia water (concentration 27%) are uniformly mixed, and then tetraethyl orthosilicate is added, so that the use amount ratio of the nano tungsten oxide coated with the first shell layer, the tetraethyl orthosilicate, water, anhydrous ethanol and ammonia water is 4 g:12 mL:100 mL:100 mL:80 mL, and the reaction is carried out at 30°C for 2 h; after the reaction is completed, the anhydrous ethanol is washed and vacuum dried to obtain nano tungsten oxide coated with a second shell layer, i.e. the nano tungsten oxide microcapsules;

[0078] (2) mixing LDPE, polypropylene, maleic anhydride grafted polyethylene, antioxidant 1010, carbon black, calcium carbonate, mica powder uniformly, then adding nano tungsten oxide microcapsule, stirring uniformly at 200 rpm to obtain a mixture;

[0079] (3) extruding and granulating the mixture in a double screw extruder at 200℃ to obtain the reversible photochromic pigment masterbatch.

[0080] Example 2

[0081] The reversible photochromic pigment masterbatch comprises the following raw materials in mass fraction: 100 parts of LDPE (molecular weight 100,000), 20 parts of nano tungsten oxide microcapsule, 6 parts of maleic anhydride grafted polypropylene, 5 parts of antioxidant 1685, 2 parts of titanium dioxide, 10 parts of talc, and 5 parts of mica powder.

[0082] The preparation method of the reversible photochromic pigment masterbatch comprises the following steps:

[0083] (1) mixing nano tungsten oxide (particle size 100 nm), Tween 80, potassium persulfate, and liquid paraffin uniformly according to the ratio of 5 g:5:1 g:100 mL to obtain an oil phase; mixing cetyltrimethylammonium bromide, methyl methacrylate, and water uniformly according to the ratio of 0.3 g:6 g:100 mL to obtain an aqueous phase; emulsifying the oil phase into the aqueous phase according to the volume ratio of 1:1 for 10 min to obtain an emulsion; heating the emulsion to 80℃ for 2 h of polymerization reaction to obtain nano tungsten oxide coated with a first shell layer; mixing the nano tungsten oxide coated with the first shell layer, water, anhydrous ethanol, and ammonia water (concentration 25%) uniformly, then adding tetraethyl orthosilicate, so that the use amount ratio of the nano tungsten oxide coated with the first shell layer, the tetraethyl orthosilicate, water, anhydrous ethanol, and ammonia water is 2 g:15 mL:120 mL:150 mL:100 mL, and reacting at 30℃ for 2 h, after the reaction, washing with anhydrous ethanol and vacuum drying to obtain nano tungsten oxide coated with a second shell layer, which is the nano tungsten oxide microcapsule;

[0084] (2) mixing LDPE, maleic anhydride grafted polypropylene, antioxidant 168, titanium dioxide, talc, and mica powder uniformly, then adding nano tungsten oxide microcapsule, stirring uniformly at 150 rpm to obtain a mixture;

[0085] (3) extruding and granulating the mixture in a double screw extruder at 220℃ to obtain the reversible photochromic pigment masterbatch.

[0086] Comparative Example 1

[0087] The composition of the reversible photochromic pigment masterbatch is specifically referred to Example 1, except that the nano tungsten oxide microcapsule is replaced by nano tungsten oxide particles (particle size 50 nm).

[0088] Comparative Example 2

[0089] The composition of the masterbatch is specifically referred to Example 1, except that it does not contain the nano tungsten oxide microcapsule.

[0090] Application Example 1

[0091] The agricultural functional film comprises the following raw materials in mass fraction: LDPE (molecular weight 100,000) 100 parts, and the reversible photochromic pigment masterbatch of Example 1 28 parts.

[0092] The method for preparing the agricultural functional film comprises the following steps:

[0093] The LDPE and the reversible photochromic pigment masterbatch are mixed, extruded and granulated through a double-screw extruder at 200°C, and then blown into a film through a film blowing machine at 160°C to obtain an agricultural functional film with a thickness of 40 μm.

[0094] Application Example 2

[0095] The agricultural functional film comprises the following raw materials in mass fraction: LDPE (molecular weight 120,000) 100 parts, and the reversible photochromic pigment masterbatch of Example 2 20 parts.

[0096] The method for preparing the agricultural functional film is specifically referred to Application Example 1.

[0097] Comparative Application Example 1

[0098] The agricultural functional film comprises the following raw materials in mass fraction: LDPE (molecular weight 100,000) 100 parts, and the reversible photochromic pigment masterbatch of Comparative Example 1 28 parts.

[0099] The method for preparing the agricultural functional film is specifically referred to Application Example 1.

[0100] Comparative Application Example 2

[0101] The agricultural functional film comprises the following raw materials in mass fraction: LDPE (molecular weight 100,000) 100 parts, and the masterbatch of Comparative Example 2 28 parts.

[0102] The method for preparing the agricultural functional film is specifically referred to Application Example 1.

[0103] The transmittance of the agricultural functional films of Application Examples 1-2 and Comparative Examples 1-2 is tested by the following method: Before ultraviolet light irradiation, the transmittance is recorded by an Ocean Optics spectrometer. Then the agricultural functional film is irradiated under 5 mW·cm -2 of 365 nm ultraviolet light for 1 min, and the transmittance is recorded by the Ocean Optics spectrometer. The transmittance data is compared by taking 350 nm as the reference wavelength point. The results are shown in Table 1.

[0104] Table 1 Transmittance of agricultural functional films

[0105] Sample Transmittance % before light exposure Transmittance % after light exposure Discoloration performance Application Example 1 89.23 64.58 Yes Application Example 2 91.45 66.36 Yes Comparative Application Example 1 90.14 79.27 Yes Comparative Application Example 2 89.92 89.89 No

[0106] As shown in Table 1, the agricultural functional film prepared based on the reversible photochromic pigment master batch of the application shows good color change effect, the transmittance obviously decreases after light irradiation, and the color change reaction rate is fast.

[0107] The tensile strength and elongation at break of the agricultural functional films of Test Application Examples 1-2 and Comparative Application Examples 1-2 were tested, and the results are shown in Table 2.

[0108] Table 2 Tensile strength and elongation at break of agricultural functional films

[0109] Sample Tensile strength MPa Elongation at break % Application Example 1 42.7 398 Application Example 2 41.9 386 Comparative Application Example 1 35.8 315 Comparative Application Example 2 39.2 344

[0110] As shown in Table 2, the nano tungsten oxide particles in the application are dispersed in the resin system in the form of microcapsules, which significantly improves the mechanical properties of the film and increases the compatibility of the nanoparticles and the resin.

[0111] The above is only the preferred embodiment of the application, and it should be pointed out that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the application, and these improvements and refinements should also be considered within the protection scope of the application.

Claims

1. A reversible light-changing pigment masterbatch, characterized in that: The invention comprises the following raw materials in parts by mass: 100 parts of resin, 10 to 30 parts of nano-tungsten oxide microcapsules, 5 to 10 parts of dispersing aids, 1 to 5 parts of antioxidants, 1 to 10 parts of pigments and 5 to 20 parts of fillers.

2. The reversible light-changing pigment masterbatch according to claim 1, characterized in that: The resin is one or more of polyethylene, polypropylene, poly-1-butene, and ethylene-vinyl acetate copolymer.

3. The reversible light-changing pigment masterbatch according to claim 2, characterized in that: The dispersing aid is one or more of maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, and styrene-maleic anhydride copolymer.

4. A reversible light-changing pigment masterbatch according to claim 1 or 3, characterized in that: The antioxidant is antioxidant 1010 and / or antioxidant 168.

5. The reversible light-changing pigment masterbatch according to claim 1, characterized in that: The preparation method of the nano-tungsten oxide microcapsules comprises the following steps: Mixing nano-tungsten oxide, dispersant, initiator and liquid paraffin to obtain an oil phase; mixing a surfactant, methyl methacrylate, and water to obtain an aqueous phase; The oil phase is added to the water phase for emulsification to obtain an emulsion; The emulsion is heated to perform polymerization reaction to obtain nano-tungsten oxide coated with the first shell layer; The nano-tungsten oxide coating the first shell layer, ethyl orthosilicate, water, anhydrous ethanol and ammonia solution are mixed and reacted to obtain the nano-tungsten oxide coating the second shell layer, namely the nano-tungsten oxide microcapsules.

6. The reversible light-changing pigment masterbatch according to claim 5, characterized in that: The particle size of the nano tungsten oxide is 30-100 nm.

7. The reversible light-changing pigment masterbatch according to claim 5, characterized in that: The dosage ratio of the nano-tungsten oxide, dispersant, initiator, and liquid paraffin is 5-10g:1-8g:1-10g:100mL; the dosage ratio of the surfactant, methyl methacrylate, and water is 0.1-1g:5-10g:100mL; and the dosage ratio of the nano-tungsten oxide, ethyl orthosilicate, water, anhydrous ethanol, and ammonia water coating the first shell layer is 1-5g:10-20mL:100-200mL:100-200mL:50-150mL.

8. The reversible light-changing pigment masterbatch according to claim 7, characterized in that: The emulsification time is 10 to 30 minutes; the polymerization reaction temperature is 70 to 90° C.; the polymerization reaction time is 2 to 5 hours; the reaction temperature is 25 to 40° C.; and the reaction time is 1 to 3 hours.

9. The method for preparing a reversible light-changing pigment masterbatch according to any one of claims 1 to 8, characterized in that: The following steps are involved: Mixing resin, nano-tungsten oxide microcapsules, dispersing aids, antioxidants, pigments, and fillers to obtain a mixture; The mixed material is extruded and granulated in a twin-screw extruder to obtain a reversible light-changing pigment masterbatch.

10. An agricultural functional film, characterized in that: including a reversible photochromic film layer; The reversible photochromic film layer comprises the following raw materials in parts by mass: 100 parts of base resin and 5 to 30 parts of reversible photochromic pigment masterbatch; The reversible photochromic pigment masterbatch is a reversible photochromic pigment masterbatch according to any one of claims 1 to 8.