High-adsorption cooling film for grape planting and preparation method thereof

Abstract

The invention relates to the technical field of agricultural films, in particular to a high-adsorption cooling film for grape planting and a preparation method of the high-adsorption cooling film. The high-adsorption cooling film is formed by sequentially compounding an anti-ultraviolet oxidation layer, a cooling layer and an adsorption base layer from outside to inside, wherein the anti-ultraviolet oxidation layer consists of an anti-ultraviolet agent, an antioxidant and polyethylene particles; the cooling layer is made of spiropyrane compound grafted polyethylene; the adsorption base layer is composed of mesoporous silica and polyethylene particles. According to the prepared film, the unique reversible reaction of open-loop heat absorption-closed-loop heat release of the spiropyrane compound is utilized, the phenomenon that the color of the film is deepened and sunlight can be reflected and blocked during open-loop heat absorption of the spiropyrane compound is matched, the cooling effect is achieved, meanwhile, the preparation method is conventional, raw materials are easy to obtain, the service life is long, and the cost is low. Wide application prospects are realized.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural films, and in particular to a high-absorption cooling film for grape planting and a preparation method thereof. Background Art

[0002] In the process of grape cultivation, agricultural film plays a vital role. It can not only maintain soil moisture and inhibit weed growth, but also adjust the temperature and light conditions of the microenvironment to promote the healthy growth of grapes. Although traditional polyethylene film is widely used in grape cultivation, it has some shortcomings. For example, during the high temperature period in summer, the temperature inside the film is too high, which will affect the photosynthesis and respiration of grapes, thereby affecting the yield and quality of grapes. In addition, traditional films have limited adsorption capacity for harmful gases (such as ethylene and sulfur dioxide) and excess water in the environment, and cannot effectively improve the microenvironment inside the film, which is not conducive to the growth and development of grapes.

[0003] In recent years, researchers have tried to improve the comprehensive performance of films by adding functional additives such as anti-ultraviolet agents, antioxidants, and adsorbents. However, these additives have deficiencies in dispersibility and compatibility, which limits the further improvement of film performance. At the same time, some new cooling materials such as various phase change cooling materials have also been tried in polyethylene films, but conventional phase change materials have a single cooling method and a short repeated service life. These problems limit the large-scale application of cooling films. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a high-adsorption cooling film for grape planting and a preparation method thereof, so as to solve the problems of existing agricultural films having poor cooling effect, short service life, and failing to have both good cooling performance and adsorption performance.

[0005] Based on the above purpose, the present invention provides a high-absorption cooling film for grape planting, which is composed of an anti-ultraviolet oxidation layer, a cooling layer and an adsorption base layer in sequence from the outside to the inside; The anti-ultraviolet oxidation layer is composed of an anti-ultraviolet agent, an antioxidant and polyethylene particles; The cooling layer is made of polyethylene grafted with a spiropyran compound, and the preparation method of the spiropyran compound is as follows: (1) Add 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 5-nitrosalicylic acid aldehyde to ethanol, stir, reflux for 8-10 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product. The reaction equation is as follows: Formula (1); (2) The crude product obtained in (1) was eluted with a petroleum ether / ethyl acetate system through silica gel column chromatography, and the excess elution solvent was distilled off under reduced pressure. After drying, a spiropyran compound was obtained. The product was characterized by H NMR and FTIR infrared spectroscopy. HNMR (400 MHz, Chloroform-d) δ8.19 (d, J = 2.3 Hz, 1H), 8.05 (dd, J = 7.8, 2.3 Hz, 1H), 7.14 (dd, J = 7.5, 2.2 Hz, 1H), 7.09 (d, J = 2.2 Hz, 1H), 7.01 (d, J =7.9 Hz, 1H), 6.78-6.67 (m, 2H), 5.92 (d, J = 8.4 Hz, 1H), 2.86 (s, 3H), 1.42 (s, 3H), 1.37 (s, 3H); The adsorption base layer is composed of mesoporous silicon dioxide and polyethylene particles.

[0006] Preferably, the anti-ultraviolet agent refers to 2-hydroxy-4-n-octyloxybenzophenone or 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol.

[0007] Preferably, the antioxidant refers to antioxidant 1010 or antioxidant 168.

[0008] Preferably, in said (1), the weight ratio of 5-chloro-1,3,3-trimethyl-2-methyleneindoline, 5-nitrosalicylic acid aldehyde and ethanol is 1:1:10-15.

[0009] Preferably, the (2) petroleum ether / ethyl acetate system elution refers to a gradient elution method, wherein the volume ratio of petroleum ether to ethyl acetate in each step of the eluent is 1:0, 10:1, 5:1 to 1:1.

[0010] Preferably, the temperature regulating mechanism of the spiropyran compound is: Formula (2) When the temperature of the spiropyran compound reaches the phase transition temperature, a ring-opening reaction occurs to absorb heat, and at the same time, its own color changes from transparent to dark, which can effectively block sunlight and reduce the temperature. When the temperature drops, the spiropyran compound undergoes a ring-closing reaction to release heat, and at the same time, its own color returns to transparent, which has a certain thermal insulation effect. These two reactions are reversible reactions, providing the spiropyran compound with the ability to regulate temperature.

[0011] Preferably, the particle size of the mesoporous silica is 200 nm.

[0012] Furthermore, the present invention also provides a method for preparing the above-mentioned high-adsorption cooling film for grape planting, which specifically comprises the following steps: S1: Preparation of anti-ultraviolet oxidation layer: anti-ultraviolet agent, antioxidant and polyethylene particles are mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 15-25 μm. The parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 140-150°C, the temperature of zone 2 is 160-170°C, the temperature of zone 3 is 155-165°C, the head temperature is 160°C, the screw speed is 60-80rpm, and the parameters of the blow molding machine are as follows: the blowing ratio is 2.5-3.5:1, and the traction ratio is 4-6:1; S2: Preparation of cooling layer: under nitrogen protection, polyethylene powder, ferrous chloride and benzoyl peroxide are added to ethanol and heated to 60-70°C, reacted for 30-60 minutes, then spiropyran compound is added, heated to 80-90°C, reacted for 8-10 hours, cooled to room temperature, and excess ethanol is removed by vacuum distillation. After washing and drying, spiropyran-grafted polyethylene is obtained. The spiropyran-grafted polyethylene is heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 40-60 μm. The parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 140-150°C, the temperature of zone 2 is 150-160°C, the temperature of zone 3 is 155-165°C, the head temperature is 155°C, the screw speed is 60-80rpm, and the parameters of the blow molding machine are as follows: the blowing ratio is 2.5-3.5:1, and the traction ratio is 4-6:1; S3: Preparation of adsorption base layer: mesoporous silica and polyethylene particles are mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 30-40 μm. The parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 140-150°C, the temperature of zone 2 is 160-170°C, the temperature of zone 3 is 150-160°C, the head temperature is 155°C, the screw speed is 60-80rpm, and the parameters of the blow molding machine are as follows: the blowing ratio is 2.5-3.5:1, and the traction ratio is 4-6:1; S4: stack the anti-ultraviolet oxidation layer, the cooling layer and the adsorption base layer from the outside to the inside in sequence, and use a hot press to set the temperature to 80-100°C, the pressure to 5-7MPa, and the holding time to 3-5min for composite molding, and after cooling, a high adsorption cooling film for grape planting is obtained.

[0013] Preferably, the weight ratio of the anti-ultraviolet agent, antioxidant and polyethylene particles in S1 is 0.03-0.05:0.01-0.02:1.

[0014] Preferably, the weight ratio of the spiropyran compound, polyethylene powder, ferrous chloride, benzoyl peroxide and ethanol in S2 is 0.1-0.2:1:0.005-0.01:0.015-0.03:10-14, and the reaction equation is as follows: Formula (3), the product was characterized by FTIR infrared spectroscopy.

[0015] Preferably, the weight ratio of the mesoporous silica and polyethylene particles in S3 is 0.1-0.16:1.

[0016] Beneficial effects of the present invention: 1. The present invention introduces spiropyran compounds into the film and uses its unique ring-opening heat absorption characteristics to achieve cooling. The present invention actively shields external ultraviolet light through the structural design of the film, so that the spiropyran compound changes from ultraviolet light-temperature dual response to ring-opening reaction only when the phase transition temperature is reached. The change in molecular structure enables it to absorb a large amount of heat energy, thereby effectively reducing the surface temperature of the film. At the same time, the color of the spiropyran compound after ring opening becomes darker, which can block sunlight from passing through the film and reduce the heating effect of solar radiation on grape plants. Finally, under the condition of low temperature in winter, even if there is light, the spiropyran compound in the film prepared by the present invention will not undergo a ring-opening reaction to deepen its own color, thereby maintaining a good light transmittance, ensuring a certain thermal insulation effect, and providing suitable conditions for grape growth.

[0017] 2. The film of the present invention adopts a three-layer composite structure, and the materials of each layer cooperate with each other to improve the overall mechanical properties. The antioxidant and anti-ultraviolet agent in the anti-ultraviolet oxidation layer enhance the anti-aging property of polyethylene, the spiropyran compound grafted polyethylene in the cooling layer forms a compact structure through chemical bonding to improve the tensile strength, and the mesoporous silica in the adsorption base layer is mixed with polyethylene particles to increase the rigidity of the material, ensuring that the film can withstand the mechanical stress of the external environment during the grape planting process and reduce the risk of breakage and tearing.

[0018] 3. Although the spiropyran compound used in the present invention has good color change performance, it is easy to degrade its molecular structure under long-term ultraviolet irradiation, resulting in its performance degradation and limited service life. The present invention effectively blocks the direct effect of ultraviolet rays on the spiropyran compound by adding an anti-ultraviolet oxidation layer, reducing the occurrence of photo-oxidative degradation. The anti-ultraviolet agent in the anti-ultraviolet oxidation layer can absorb and quench ultraviolet rays, and the antioxidant can capture and eliminate the free radicals generated in the photo-oxidation process, further inhibiting the aging reaction. The synergistic effect of the two significantly improves the stability and durability of the spiropyran compound, prolongs its service life in the film, and by modifying the molecular structure of the spiropyran compound, a nitro group is introduced. The nitro group, as a strong electron-withdrawing group, greatly reduces the phase transition temperature of the spiropyran compound. In actual use, a ring-opening reaction can occur in the face of a suitable temperature, and it is no longer necessary to rely on ultraviolet light to cause a ring-opening reaction, reducing the impact of the anti-ultraviolet oxidation layer blocking ultraviolet light, thereby ensuring that the film can continue to play a cooling effect during the grape planting process, reducing the economic losses and replacement costs caused by the decline in film performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the H NMR spectrum of the spiropyran compound; Figure 2 This is the FTIR infrared spectrum of spiropyran compounds. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0021] The sources of the reagents and raw materials used in the embodiments of the present invention are as follows: 5-Chloro-1,3,3-trimethyl-2-methyleneindoline was purchased from Shanghai Haohong Biopharmaceutical Technology Co., Ltd., item number 1039958, purity 95%; 5-Nitrosalicylic acid aldehyde was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., item number N814745, purity 98%; 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., item number H834139, purity 98%; Antioxidant 1010 was purchased from Shanghai MacLean Biochemical Technology Co., Ltd., item number P750268, purity 98%; Mesoporous silica was purchased from Shanghai MacLean Biochemical Technology Co., Ltd. Polyethylene particles were purchased from Shanghai Dingfen Chemical Technology Co., Ltd., item number M758933, particle size 200nm; polyethylene particles were purchased from Shanghai Dingfen Chemical Technology Co., Ltd., item number P06526; polyethylene powder was purchased from Wuxi Baimao Plastic Co., Ltd., particle size 200-500 mesh; salicylic acid aldehyde was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., item number S817504, purity 98%; paraffin was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., item number P815421; silicon dioxide was purchased from Shanghai Yuanye Biotechnology Co., Ltd., item number S25691, particle size 100 mesh; polyethylene film was purchased from Kingfa Technology Co., Ltd., with thicknesses of 20μm, 50μm, and 35μm.

[0022] Example 1: A specific preparation method of a high-absorption cooling film for grape planting, comprising the following process: (1) Add 1 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 1 kg of 5-nitrosalicylic acid aldehyde to 10 kg of ethanol, stir, reflux for 8 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of anti-ultraviolet oxidation layer: 300 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 100 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 15 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 140°C, the temperature of zone 2 was 160°C, the temperature of zone 3 was 155°C, the head temperature was 160°C, the screw speed was 60 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 2.5:1 and the traction ratio was 4:1; (4) Preparation of cooling layer: under nitrogen protection, 10 kg polyethylene powder, 50 g ferrous chloride and 150 g benzoyl peroxide were added to 100 kg ethanol and heated to 60 °C, reacted for 30 min, then 1 kg spiropyran compound obtained in (2) was added, heated to 80 °C, reacted for 8 h, cooled to room temperature, and excess ethanol was removed by vacuum distillation. After washing and drying, spiropyran grafted polyethylene was obtained. The spiropyran grafted polyethylene was heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 40 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 140 °C, the temperature of zone 2 was 150 °C, the temperature of zone 3 was 155 °C, the head temperature was 155 °C, the screw speed was 60 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 2.5:1, and the traction ratio was 4:1; (5) Preparation of adsorption base layer: 1 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 30 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 140°C, the temperature of zone 2 was 160°C, the temperature of zone 3 was 150°C, the temperature of the die head was 155°C, the screw speed was 60 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 2.5:1, and the pulling ratio was 4:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 80° C., a pressure of 5 MPa, and a holding time of 3 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0023] Example 2: A specific preparation method of a high-absorption cooling film for grape planting, comprising the following process: (1) Add 1.5 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 1.5 kg of 5-nitrosalicylic acid aldehyde to 18 kg of ethanol, stir, reflux for 9 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of anti-ultraviolet oxidation layer: 400 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 150 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 20 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 160°C, the head temperature was 160°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1; (4) Preparation of cooling layer: under nitrogen protection, 10 kg polyethylene powder, 75 g ferrous chloride and 225 g benzoyl peroxide were added to 120 kg ethanol and heated to 65 °C, reacted for 45 min, then 1.5 kg spiropyran compound obtained in (2) was added, heated to 85 °C, reacted for 9 h, cooled to room temperature, and excess ethanol was removed by vacuum distillation. After washing and drying, spiropyran grafted polyethylene was obtained. The spiropyran grafted polyethylene was heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 50 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145 °C, the temperature of zone 2 was 155 °C, the temperature of zone 3 was 160 °C, the head temperature was 155 °C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1. (5) Preparation of adsorption base layer: 1.3 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 35 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 155°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the pulling ratio was 5:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 90° C., a pressure of 6 MPa, and a holding time of 4 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0024] Example 3: A specific preparation method of a high-absorption cooling film for grape planting, comprising the following process: (1) Add 2 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 2 kg of 5-nitrosalicylic acid aldehyde to 30 kg of ethanol, stir, reflux for 10 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of anti-ultraviolet oxidation layer: 500 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 200 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 25 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 150°C, the temperature of zone 2 was 170°C, the temperature of zone 3 was 165°C, the head temperature was 160°C, the screw speed was 80 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3.5:1 and the traction ratio was 6:1; (4) Preparation of cooling layer: under nitrogen protection, 10 kg polyethylene powder, 100 g ferrous chloride and 300 g benzoyl peroxide were added to ethanol and heated to 70 °C, reacted for 60 min, then 2 kg spiropyran compound obtained in (2) was added, heated to 90 °C, reacted for 10 h, cooled to room temperature, and excess ethanol was removed by vacuum distillation. After washing and drying, spiropyran grafted polyethylene was obtained. The spiropyran grafted polyethylene was heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 60 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 150 °C, the temperature of zone 2 was 160 °C, the temperature of zone 3 was 165 °C, the head temperature was 155 °C, the screw speed was 80 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3.5:1, and the traction ratio was 6:1. (5) Preparation of adsorption base layer: 1.6 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 40 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 150°C, the temperature of zone 2 was 170°C, the temperature of zone 3 was 160°C, the head temperature was 155°C, the screw speed was 80 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3.5:1, and the pulling ratio was 6:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 100° C., a pressure of 7 MPa, and a holding time of 5 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0025] Comparative Example 1: The difference between Comparative Example 1 and Example 2 is that the spiropyran compound does not contain a nitro group. The specific preparation process is as follows: (1) Add 1.5 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 1.5 kg of salicylic acid aldehyde to 18 kg of ethanol, stir, reflux for 9 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of anti-ultraviolet oxidation layer: 400 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 150 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 20 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 160°C, the head temperature was 160°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1; (4) Preparation of cooling layer: under nitrogen protection, 10 kg polyethylene powder, 75 g ferrous chloride and 225 g benzoyl peroxide were added to 120 kg ethanol and heated to 65 °C, reacted for 45 min, then 1.5 kg spiropyran compound obtained in (2) was added, heated to 85 °C, reacted for 9 h, cooled to room temperature, and excess ethanol was removed by vacuum distillation. After washing and drying, spiropyran grafted polyethylene was obtained. The spiropyran grafted polyethylene was heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 50 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145 °C, the temperature of zone 2 was 155 °C, the temperature of zone 3 was 160 °C, the head temperature was 155 °C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1. (5) Preparation of adsorption base layer: 1.3 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 35 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 155°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the pulling ratio was 5:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 90° C., a pressure of 6 MPa, and a holding time of 4 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0026] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that the spiropyran compound and the polyethylene are physically blended, and the specific preparation process is as follows: (1) Add 1.5 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 1.5 kg of 5-nitrosalicylic acid aldehyde to 18 kg of ethanol, stir, reflux for 9 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of anti-ultraviolet oxidation layer: 400 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 150 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 20 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 160°C, the head temperature was 160°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1; (4) Preparation of cooling layer: 10 kg of polyethylene powder and 1.5 kg of spiropyran compound obtained in (2) were mixed, heated and extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 50 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 155°C, the temperature of zone 3 was 160°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the traction ratio was 5:1; (5) Preparation of adsorption base layer: 1.3 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 35 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 155°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the pulling ratio was 5:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 90° C., a pressure of 6 MPa, and a holding time of 4 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0027] Comparative Example 3: The difference between Comparative Example 3 and Example 2 is that the high-absorption cooling film for grape cultivation does not contain an anti-ultraviolet oxidation adsorption layer. The specific preparation process is as follows: (1) Add 1.5 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 1.5 kg of 5-nitrosalicylic acid aldehyde to 18 kg of ethanol, stir, reflux for 9 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of cooling layer: under nitrogen protection, 10 kg polyethylene powder, 75 g ferrous chloride and 225 g benzoyl peroxide were added to 120 kg ethanol and heated to 65 °C, reacted for 45 min, then 1.5 kg spiropyran compound obtained in (2) was added, heated to 85 °C, reacted for 9 h, cooled to room temperature, and excess ethanol was removed by vacuum distillation. After washing and drying, spiropyran grafted polyethylene was obtained. The spiropyran grafted polyethylene was heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 50 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145 °C, the temperature of zone 2 was 155 °C, the temperature of zone 3 was 160 °C, the head temperature was 155 °C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1. (4) Preparation of adsorption base layer: 1.3 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 35 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 155°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the pulling ratio was 5:1; (6) The cooling layer and the adsorption base layer are stacked from the outside to the inside in sequence, and a hot press is set to 90°C, 6MPa, and 4min of holding time for hot pressing to form a composite film. After cooling, a high adsorption cooling film for grape planting is obtained.

[0028] Comparative Example 4: The difference between Comparative Example 4 and Example 2 is that the cooling layer is made of paraffin and polyethylene, and the specific preparation process is as follows: (1) Preparation of anti-ultraviolet oxidation layer: 400 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 150 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 20 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 160°C, the head temperature was 160°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1; (2) Preparation of cooling layer: 10 kg of polyethylene powder and 1.5 kg of paraffin were mixed, heated and extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 50 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 155°C, the temperature of zone 3 was 160°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the traction ratio was 5:1; (5) Preparation of adsorption base layer: 1.3 kg of mesoporous silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 35 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 155°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the pulling ratio was 5:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 90° C., a pressure of 6 MPa, and a holding time of 4 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0029] Comparative Example 5: The difference between Comparative Example 5 and Example 2 is that the adsorption substrate is made of silicon dioxide and polyethylene, and the specific preparation process is as follows: (1) Add 1.5 kg of 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 1.5 kg of 5-nitrosalicylic acid aldehyde to 18 kg of ethanol, stir, reflux for 9 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; (3) Preparation of anti-ultraviolet oxidation layer: 400 g of 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol, 150 g of antioxidant 1010 and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 20 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 160°C, the head temperature was 160°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1; (4) Preparation of cooling layer: under nitrogen protection, 10 kg polyethylene powder, 75 g ferrous chloride and 225 g benzoyl peroxide were added to 120 kg ethanol and heated to 65 °C, reacted for 45 min, then 1.5 kg spiropyran compound obtained in (2) was added, heated to 85 °C, reacted for 9 h, cooled to room temperature, and excess ethanol was removed by vacuum distillation. After washing and drying, spiropyran grafted polyethylene was obtained. The spiropyran grafted polyethylene was heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 50 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145 °C, the temperature of zone 2 was 155 °C, the temperature of zone 3 was 160 °C, the head temperature was 155 °C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1 and the traction ratio was 5:1. (5) Preparation of adsorption base layer: 1.3 kg of silica and 10 kg of polyethylene particles were mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 35 μm. The parameters of the twin-screw extruder were as follows: the temperature of zone 1 was 145°C, the temperature of zone 2 was 165°C, the temperature of zone 3 was 155°C, the head temperature was 155°C, the screw speed was 70 rpm, and the parameters of the blow molding machine were as follows: the blowing ratio was 3:1, and the traction ratio was 5:1; (6) The anti-ultraviolet oxidation layer, the cooling layer, and the adsorption base layer are stacked in sequence from the outside to the inside, and are hot-pressed and composited by a hot press machine with a temperature of 90° C., a pressure of 6 MPa, and a holding time of 4 min. After cooling, a high-adsorption cooling film for grape planting is obtained.

[0030] Comparative Example 6: The difference between Comparative Example 6 and Example 2 is that the high-adsorption cooling film for grape cultivation is made of three layers of polyethylene films with thicknesses of 20 μm, 50 μm and 35 μm respectively by hot pressing and compounding. The specific process is as follows: Three layers of polyethylene films with thicknesses of 20 μm, 50 μm and 35 μm were stacked from outside to inside, and composited by hot pressing with a hot press machine set at 90°C, a pressure of 6 MPa and a holding time of 4 min. After cooling, a high-adsorption cooling film for grape planting was obtained.

[0031] Performance Test: 1. Mechanical property test: A universal material testing machine was used to perform tensile tests and elongation at break tests on the films prepared in Examples 1-3 and Comparative Example 6. The experimental results are shown in Table 1.

[0032] 2. Anti-aging performance test: Use xenon lamp aging test box, irradiance: 0.55 W / m² (at 340 nm); Blackboard temperature: 60±2°C; humidity: 50±5% RH; cycle: 102 minutes of illumination + 18 minutes of water spraying; time: 1000h. The films prepared in Examples 1-3 and Comparative Example 3 were subjected to anti-aging tests, and the performance retention rate of each experimental group after aging time was calculated: such as tensile strength retention rate = (initial strength - strength after aging) / initial strength × 100%; transmittance retention rate = (initial transmittance - transmittance after aging) / initial transmittance × 100%. The experimental results are shown in Table 2.

[0033] 3. Cooling performance test: The outdoor environment at 35°C with and without light and at 25°C with and without light were simulated respectively. The simulated light is a cold light condition and will not increase the ambient temperature. The cooling temperature and the time required to reach the lowest temperature of the films prepared in Examples 1-3 and Comparative Examples 1-4 were tested. The experimental results are shown in Table 3.

[0034] 4. Adsorption performance test: The films prepared in Examples 1-3 and Comparative Example 5 were subjected to an adsorption performance test. The test samples were placed in an environmental simulation box. The environment in the box was kept consistent. The moisture concentration, ethylene concentration, and SO2 concentration before the test were recorded. The moisture concentration, ethylene concentration, and SO2 concentration in the box were recorded after the test. The adsorption rate of the film was calculated and the adsorption equilibrium time was recorded. The adsorption rate = (initial concentration - residual concentration) / initial concentration × 100%. The experimental results are shown in Table 4.

[0035] 5. Light transmittance test: The films prepared in Examples 1-3 and Comparative Example 3 were placed in a direct light environment simulating an outdoor sunny day with temperatures of 25°C, 30°C, and 35°C for 2 hours, wherein the direct light is cold light and does not increase the ambient temperature. The light transmittance of the films was tested by a spectrophotometer. The experimental data are shown in Table 5.

[0036] Table 1 Mechanical properties

[0037] Table 2 Anti-aging performance

[0038] Table 3 Cooling performance

[0039] Table 4 Adsorption performance

[0040] Table 5 Light transmittance

[0041] Data Analysis: It can be seen from the data in Tables 1-5 that the high-adsorption cooling film for grape planting prepared by the present invention in Examples 1-3 has good mechanical properties and anti-aging properties, and has a good cooling effect. The cooling effect is not affected by light, and it also has a certain adsorption effect on some harmful substances that may exist in the grape growth process. Among them, the comprehensive performance of Example 2 is the best.

[0042] It can be seen from the data in Table 1 that compared with the film formed by hot-pressing and compounding three layers of ordinary polyethylene used in Comparative Example 6, Example 2 has no decrease in mechanical properties and is even slightly better than Comparative Example 6. This may be because the film prepared in Example 2 comprises an anti-ultraviolet oxidation layer, a cooling layer and an adsorption base layer, and the materials of each layer cooperate with each other to improve the overall mechanical properties. The antioxidant and anti-ultraviolet agent in the anti-ultraviolet oxidation layer not only provide protective performance, but also enhance the toughness of polyethylene. The spiropyran compound grafted polyethylene in the cooling layer is chemically bonded to form a tighter structure, which improves the tensile strength. The mixing of mesoporous silica and polyethylene particles in the adsorption base layer increases the rigidity of the material and helps to improve the elongation at break.

[0043] From the data in Table 2, it can be seen that Example 2 has significantly improved anti-aging performance compared to Comparative Example 3. This may be because the film prepared in Example 2 has an anti-ultraviolet oxidation layer, in which the anti-ultraviolet agent can effectively absorb and quench ultraviolet rays, reduce the direct effect of ultraviolet rays on the polyethylene molecular chain, thereby reducing the occurrence of photo-oxidative degradation, and the antioxidant can capture and eliminate the free radicals generated by polyethylene during the photo-oxidation process, further inhibiting the aging reaction. The synergistic effect of the two enables the film to maintain a high tensile strength and transmittance under long-term illumination and high temperature conditions, and also protects the spiropyran compound from irreversible ring-opening and ring-closing reactions when facing ultraviolet irradiation for a long time. The spiropyran compound cannot close the ring, and its own color cannot change from dark to light, resulting in a decrease in transmittance.

[0044] It can be seen from the data in Table 3 that the film prepared in Example 2 has good cooling performance and the cooling effect is not affected by light. This may be because the spiropyran compound used in Example 2 contains nitro, which, as a strong electron-withdrawing group, greatly reduces the phase change enthalpy of the spiropyran compound, so that even if the spiropyran compound is shielded from ultraviolet light, it can quickly open the ring and absorb heat when it reaches the phase change temperature, thereby avoiding the influence of environmental factors on the cooling performance; the spiropyran compound is evenly distributed in the polyethylene film by the grafting method, thereby avoiding the agglomeration caused by physical blending and increasing the spiropyran compound. The contact area between the compound and the outside world is larger, making it easier to respond to temperature changes, thereby increasing the cooling temperature and reducing the time required for cooling. Finally, the cooling performance of spiropyran compounds is better than that of traditional paraffin wax. This is because spiropyran compounds not only absorb heat through their own phase change, but also darken their color through a ring-opening reaction, and can further reflect and block sunlight, thereby synergistically achieving a cooling effect. Paraffin wax only relies on its own phase change to achieve a cooling effect, and its cooling performance is limited. At the same time, the higher phase change temperature of paraffin wax restricts its use environment, and it is not suitable for use in the field of agricultural films.

[0045] It can be seen from the data in Table 4 that the film performance of Example 2 is better than that of Comparative Example 5. This may be because the mesoporous silica used in Example 2 has a higher specific surface area, and there are a large number of active adsorption sites on its surface, which can form a strong van der Waals force or chemical bond with the adsorbed molecules, thereby improving the adsorption capacity of substances such as water, ethylene and sulfur dioxide. The adsorption base layer in Comparative Example 5 uses ordinary silica, which has a relatively low specific surface area and a wide and uneven pore size distribution, resulting in a limited number of adsorption sites and a weak adsorption capacity for target substances. In addition, the pore size of ordinary silica may be larger or smaller, and its adsorption effect will be limited for gas molecules and organic molecules of a specific size.

[0046] It can be seen from the data in Table 5 that the light transmittance of the film prepared in Example 2 is only affected by temperature. This may be because the anti-ultraviolet oxidation layer shields ultraviolet light, so that the spiropyran compound only relies on temperature to reach the phase change temperature to open the ring and deepen its own color, but no longer responds to light. This is beneficial for this film in the summer, when facing high-temperature sunlight, through phase change and its own color darkening, absorbing heat, blocking sunlight, and achieving a cooling effect; in winter, in an environment with sunlight but the temperature does not reach the phase change temperature, it maintains good light transmittance, and has a certain thermal insulation effect when used in a winter environment, which broadens the scope of use of this film, avoids frequent replacement, and reduces the cost of use.

[0047] It should be understood by those skilled in the art that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A high-absorption cooling film for grape planting, characterized in that: From the outside to the inside, it is composed of an anti-ultraviolet oxidation layer, a cooling layer and an adsorption base layer; The anti-ultraviolet oxidation layer is composed of an anti-ultraviolet agent, an antioxidant and polyethylene particles; The cooling layer is made of polyethylene grafted with a spiropyran compound, and the preparation method of the spiropyran compound is as follows: (1) Add 5-chloro-1,3,3-trimethyl-2-methyleneindoline and 5-nitrosalicylic acid aldehyde to ethanol, stir, reflux for 8-10 hours, cool to room temperature, and remove excess ethanol by vacuum distillation to obtain a crude product; (2) The crude product obtained in (1) is eluted by silica gel column chromatography using a petroleum ether / ethyl acetate system, and the excess elution solvent is removed by vacuum distillation, followed by drying to obtain a spiropyran compound; The adsorption base layer is composed of mesoporous silicon dioxide and polyethylene particles.

2. The high adsorption cooling film for grape planting according to claim 1, characterized in that: The anti-ultraviolet agent refers to 2-hydroxy-4-n-octyloxybenzophenone or 2-(2H-benzotriazole-2-yl)-4,6-di-tert-amylphenol.

3. The high adsorption cooling film for grape planting according to claim 1, characterized in that: The antioxidant refers to antioxidant 1010 or antioxidant 168.

4. The high adsorption cooling film for grape planting according to claim 1, characterized in that: In the (1), the weight ratio of 5-chloro-1,3,3-trimethyl-2-methyleneindoline, 5-nitrosalicylic acid aldehyde and ethanol is 1:1:10-15.

5. The high adsorption cooling film for grape planting according to claim 1, characterized in that: The (2) petroleum ether / ethyl acetate system elution refers to a gradient elution method, wherein the volume ratio of petroleum ether to ethyl acetate in each step of the eluent is 1:0, 10:1, 5:1 to 1:

1.

6. The high adsorption cooling film for grape planting according to claim 1, characterized in that: The particle size of the mesoporous silica is 200 nm.

7. The method for preparing the high-adsorption cooling film for grape planting according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Preparation of anti-ultraviolet oxidation layer: anti-ultraviolet agent, antioxidant and polyethylene particles are mixed, heated and co-extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain an anti-ultraviolet oxidation layer with a thickness of 15-25 μm. The parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 140-150°C, the temperature of zone 2 is 160-170°C, the temperature of zone 3 is 155-165°C, the head temperature is 160°C, the screw speed is 60-80rpm, and the parameters of the blow molding machine are as follows: the blowing ratio is 2.5-3.5:1, and the traction ratio is 4-6:1; S2: Preparation of cooling layer: under nitrogen protection, polyethylene powder, ferrous chloride and benzoyl peroxide are added to ethanol and heated to 60-70°C, reacted for 30-60 minutes, then spiropyran compound is added, heated to 80-90°C, reacted for 8-10 hours, cooled to room temperature, and excess ethanol is removed by vacuum distillation. After washing and drying, spiropyran-grafted polyethylene is obtained. The spiropyran-grafted polyethylene is heated and extruded by a twin-screw extruder and blown into a film by a blow molding machine to obtain a cooling layer with a thickness of 40-60 μm. The parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 140-150°C, the temperature of zone 2 is 150-160°C, the temperature of zone 3 is 155-165°C, the head temperature is 155°C, the screw speed is 60-80rpm, and the parameters of the blow molding machine are as follows: the blowing ratio is 2.5-3.5:1, and the traction ratio is 4-6:1; S3: Preparation of adsorption base layer: mesoporous silica and polyethylene particles are mixed, heated and co-extruded by a twin-screw extruder, and blown into a film by a blow molding machine to obtain an adsorption base layer with a thickness of 30-40 μm. The parameters of the twin-screw extruder are as follows: the temperature of zone 1 is 140-150°C, the temperature of zone 2 is 160-170°C, the temperature of zone 3 is 150-160°C, the head temperature is 155°C, the screw speed is 60-80rpm, and the parameters of the blow molding machine are as follows: the blowing ratio is 2.5-3.5:1, and the traction ratio is 4-6:1; S4: stack the anti-ultraviolet oxidation layer, the cooling layer and the adsorption base layer from the outside to the inside in sequence, and use a hot press to set the temperature to 80-100°C, the pressure to 5-7MPa, and the holding time to 3-5min for composite molding, and after cooling, a high adsorption cooling film for grape planting is obtained.

8. The method for preparing the high-adsorption cooling film for grape planting according to claim 7, characterized in that: The weight ratio of the anti-ultraviolet agent, antioxidant and polyethylene particles in S1 is 0.03-0.05:0.01-0.02:

1.

9. The method for preparing the high-adsorption cooling film for grape planting according to claim 7, characterized in that: The weight ratio of the spiropyran compound, polyethylene powder, ferrous chloride, benzoyl peroxide and ethanol in S2 is 0.1-0.2:1:0.005-0.01:0.015-0.03:10-14.

10. The method for preparing a high-adsorption cooling film for grape planting according to claim 7, characterized in that: The weight ratio of the mesoporous silica and polyethylene particles in the S3 is 0.1-0.16:1.

Images