Temperature-control bubble greenhouse film and preparation method thereof

Abstract

The invention discloses a temperature-control bubble greenhouse film and a preparation method thereof, and belongs to the technical field of macromolecular agricultural greenhouse films. The temperature-control bubble shed film is prepared from the following raw materials in parts by weight: 65 to 79 parts of modified EVOH, 16 to 24 parts of foam stabilizing master batch, 10 to 17 parts of linear low-density polyethylene, 2 to 6 parts of polyethylene glycol, 12 to 20 parts of maleic anhydride grafted polypropylene, 2 to 5 parts of diglycerol stearate and 3 to 7 parts of dioctyl phthalate. The modified EVOH is prepared from the following raw materials: an ethylene-vinyl alcohol copolymer, isobornyl methacrylate and tert-butyl peroxybenzoate; the foam stabilizing master batch is prepared from the following raw materials: EVA (Ethylene Vinyl Acetate) resin particles, polyether modified polydimethylsiloxane, hydroxypropyl methyl cellulose, nano calcium carbonate, nano titanium dioxide and maleic anhydride grafted polyethylene. The temperature-control bubble greenhouse film provided by the invention has excellent heat insulation and temperature control effects, and can still maintain better mechanical properties in a low-temperature environment.

Description

Technical Field

[0001] The invention relates to a temperature-controlling bubble greenhouse film and a preparation method thereof, belonging to the technical field of polymer agricultural greenhouse films. Background Art

[0002] Agricultural greenhouses are essential facilities for modern agricultural production, and their performance directly impacts the growing environment and yield of crops. Traditional greenhouse films have shortcomings in temperature control and weather resistance, leading to issues such as high temperatures in the summer that can burn crops, poor insulation in the winter, and a short service life.

[0003] The prior art with publication number CN113524612A discloses a chemical foaming method for multifunctional diffuse scattering bubble agricultural film, which uses a mixture of polymer granular materials and foaming masterbatch, adds a foaming agent to the middle layer or the middle combination layer, and produces gas foaming during high temperature, high pressure, shear mixing and compression in the screw, and finally extrudes the composite film. The foaming agent uses azodicarbonamide, but the AC foaming agent decomposes to produce toxic byproducts such as ammonia and carbon monoxide, and the tail gas needs to be treated, which is not in line with the green manufacturing trend.

[0004] Publication No. CN107722330A discloses a method for preparing highly efficient thermal insulation agricultural plastic greenhouse film. The method involves dissolving polyvinyl chloride (PVC) in a supercritical fluid of carbon dioxide / tetrahydrofuran, suspending ultrafine mica particles and 4,4-oxobis(benzenesulfonylhydrazine) (OBSH) foaming agent in the solvent, and rapidly reducing the pressure to allow the PVC to gradually precipitate and deposit on the surfaces of the mica particles and OBSH foaming agent. The film is then mixed evenly with a film-forming material, followed by extrusion blow molding, cooling, corona treatment, and curling to produce a highly efficient thermal insulation greenhouse film. This method offers excellent infrared barrier properties, but the material becomes brittle at low temperatures, affecting mechanical properties and making it unsuitable for winter use.

[0005] Therefore, it can be seen that the greenhouse films of the existing technology still have problems such as the material production process is not environmentally friendly, poor low-temperature weather resistance, and reduced material performance. Summary of the Invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a temperature-controlled bubble greenhouse film and achieves the following invention purposes: the present invention provides a temperature-controlled bubble greenhouse film, the production process of which is energy-saving and environmentally friendly and does not produce toxic and harmful by-products; the present invention provides a method for preparing a temperature-controlled bubble greenhouse film, and the prepared temperature-controlled bubble greenhouse film has good mechanical properties and strong low-temperature weather resistance.

[0007] To achieve the above objectives, the technical solutions adopted are as follows: The invention provides a temperature-controlled bubble greenhouse film. The raw materials for preparing the temperature-controlled bubble greenhouse film include, in parts by weight, 65-79 parts of modified EVOH, 16-24 parts of foam-stabilizing masterbatch, 10-17 parts of linear low-density polyethylene, 2-6 parts of polyethylene glycol, 12-20 parts of maleic anhydride grafted polypropylene, 2-5 parts of stearic acid diglyceride, and 3-7 parts of dioctyl phthalate.

[0008] The modified EVOH is prepared by using raw materials comprising, by weight, 90-105 parts of ethylene-vinyl alcohol copolymer (EVOH), 5-10 parts of isobornyl methacrylate, and 0.2-0.5 parts of tert-butyl perbenzoate.

[0009] The foam stabilizing masterbatch is prepared from the following raw materials in parts by weight: 22-25 parts of EVA resin particles, 6-9 parts of polyether-modified polydimethylsiloxane, 0.8-2 parts of hydroxypropyl methylcellulose, 3-5 parts of nano-calcium carbonate, 1-2 parts of nano-titanium dioxide, and 8-12 parts of maleic anhydride-grafted polyethylene.

[0010] The ethylene-vinyl alcohol copolymer (EVOH) used in the present invention has an ethylene content of 32%.

[0011] The polyether-modified polydimethylsiloxane used in the present invention has a viscosity (25°C) of CS: 800-1200 and a surface tension (25°C) of mN / m: 21.0-24.0.

[0012] The EVA resin particles used in the present invention have a particle size of 2-3 mm and a vinyl acetate content of 10-15%.

[0013] The maleic anhydride grafted polyethylene (PE-G-MAH) used in the present invention has a grafting rate of 0.8-0.9 MA%.

[0014] The maleic anhydride grafted polypropylene (PP-G-MAH) used in the present invention has a grafting rate of 0.9-1.1MA%.

[0015] The nano titanium dioxide used in the present invention has a particle size of 60 to 100 nm.

[0016] The polyethylene glycol used in the present invention is PEG2000.

[0017] The nano calcium carbonate used in the present invention has a particle size of 30 to 70 nm.

[0018] The present invention also provides a method for preparing a temperature-controlled bubble greenhouse film, comprising the following steps: Step 1: Preparation of modified EVOH EVOH and isobornyl methacrylate are added to xylene, the air in the reactor is replaced with nitrogen, the temperature is raised to 90-95°C, and the mixture is stirred until completely dissolved. The system is then heated to 150-160°C, and tert-butyl perbenzoate is added and reacted for 45-60 minutes. The reaction solution is naturally cooled to below 40°C and slowly added dropwise to a 0°C ethanol solution while stirring. After the addition is completed, stirring is continued for 30-60 minutes, and the solid is filtered and retained. The solid is vacuum dried at 80°C for 12-15 hours to obtain modified EVOH.

[0019] Nitrogen replaces the air to create an oxygen-free environment, ensuring the smooth progress of the free radical reaction. Xylene, a moderately polar organic solvent, facilitates the full dispersion of the components, forming a uniform reaction system and providing molecular-level contact conditions for subsequent reactions (grafting or copolymerization). Tert-butyl peroxybenzoate is a free radical initiator that decomposes at 150-160°C to produce active free radicals. EVOH (ethylene vinyl alcohol copolymer) is chemically modified through free radical grafting copolymerization, introducing isobornyl methacrylate (IBOMA) structural units to adjust the EVOH's properties.

[0020] Both xylene and ethanol solution are used as solvents and do not participate in the reaction. The amount of xylene used is the same as that of EVOH, the amount of ethanol solution used is 4 to 5 times the mass of xylene, and the mass concentration of ethanol solution is 50 to 95%.

[0021] Step 2: Prepare foam-stabilizing masterbatch EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate and nano-titanium dioxide are mixed evenly, added into a twin-screw extruder for mixing and extrusion, and pelletized through water-cooled strands to obtain a foam-stabilizing masterbatch with a diameter of 2 mm.

[0022] Mixing temperature is 145~155℃, screw speed is 150~200r / min, and water cooling temperature is 25±5℃.

[0023] Step 3: Foam extrusion Add modified EVOH, foam-stabilizing masterbatch, linear low-density polyethylene, polyethylene glycol, maleic anhydride grafted polypropylene, diglycerol stearate and dioctyl phthalate into a banbury mixer and knead for 30-45 minutes; transfer the melt obtained by banburying to the extrusion equipment; start the high-pressure metering pump to pressurize the melt and inject CO2. After the melt is extruded into a film, it is cooled, shaped and wound to obtain a temperature-controlled bubble shed film.

[0024] The mixing temperature is 160-180°C, and the rotor speed is 60-80 r / min. The extruder's melting section is 160-170°C, the homogenizing section is 155-165°C, and the die section is 160-168°C. The melt pressure is 18-22 MPa. The CO2 high-pressure metering pump's injection flow rate is controlled at 0.6-0.8 kg / h. The gas pressure injected by the high-pressure metering pump is 0.35-0.56 MPa higher than the melt pressure.

[0025] The beneficial effects of the present invention are as follows: The temperature-controlled bubble greenhouse film provided by the present invention has an energy-saving and environmentally friendly production process, does not produce toxic and harmful by-products, and has good mechanical properties. Its corner tear strength retention rate at -30°C is 98.3~99.5%, and its tensile strength retention rate at -30°C is 98.6~99.3%; the temperature-controlled bubble greenhouse film provided by the present invention has an infrared blocking rate of 92.9~95.5%, and has excellent heat insulation and temperature control effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Attachment Figure 1 This is the infrared spectrum of EVOH before the reaction in the step of "preparing modified EVOH" of the present invention.

[0027] Attachment Figure 2 This is the infrared spectrum of the modified EVOH after the reaction in the step of "preparing modified EVOH" of the present invention.

[0028] Attachment Figure 3 , Attachment Figure 4 This is a picture of the finished product of "a temperature-controlled bubble greenhouse film" of the present invention. DETAILED DESCRIPTION

[0029] To make the purpose, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0030] Example 1 A temperature-controlled bubble film A temperature-controlled bubble greenhouse film, the preparation raw materials of which include, in parts by weight, 70 parts of modified EVOH, 20 parts of foam-stabilizing masterbatch, 17 parts of linear low-density polyethylene, 6 parts of polyethylene glycol, 15 parts of maleic anhydride grafted polypropylene, 2 parts of stearic acid diglyceride, and 7 parts of dioctyl phthalate.

[0031] The modified EVOH is prepared by using raw materials including, by weight, 105 parts of ethylene-vinyl alcohol copolymer, 10 parts of isobornyl methacrylate, and 0.5 parts of tert-butyl perbenzoate.

[0032] The foam stabilizing masterbatch is prepared from the following raw materials in parts by weight: 25 parts of EVA resin particles, 6 parts of polyether-modified polydimethylsiloxane, 1.6 parts of hydroxypropyl methylcellulose, 3 parts of nano-calcium carbonate, 2 parts of nano-titanium dioxide, and 12 parts of maleic anhydride-grafted polyethylene.

[0033] A method for preparing a temperature-controlled bubble greenhouse film comprises the following steps: Step 1: Preparation of modified EVOH EVOH and isobornyl methacrylate were added to xylene, the air in the reactor was replaced with nitrogen, the temperature was raised to 95°C, and the mixture was stirred until completely dissolved. The system was then heated to 150°C, and tert-butyl perbenzoate was added and reacted for 45 minutes. After reacting for 45 minutes, the temperature was naturally lowered to below 40°C, and the cooled reaction solution was slowly added dropwise to a 0°C ethanol solution while stirring. After the addition was completed, stirring was continued for 60 minutes, and the solid was retained by filtration. The solid was vacuum dried at 80°C for 12 hours to obtain modified EVOH.

[0034] Both xylene and ethanol solution are used as solvents and do not participate in the reaction. The amount of xylene used is the same as that of EVOH, the amount of ethanol solution used is 5 times that of xylene, and the mass concentration of ethanol solution is 50%.

[0035] Step 2: Prepare foam-stabilizing masterbatch EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate and nano-titanium dioxide are mixed evenly, added into a twin-screw extruder for mixing and extrusion, and pelletized through water-cooled strands to obtain a foam-stabilizing masterbatch with a diameter of 2 mm.

[0036] The mixing temperature was 145°C, the screw speed was 200 r / min, and the water cooling temperature was 25±5°C.

[0037] Step 3: Foam extrusion Add modified EVOH, foam-stabilizing masterbatch, linear low-density polyethylene, polyethylene glycol, maleic anhydride grafted polypropylene, stearic acid diglyceride and dioctyl phthalate into a banbury mixer and knead for 30-45 minutes; transfer the melt obtained by banburying to a twin-screw extruder; start the high-pressure metering pump to pressurize CO2, open the CO2 injection valve, and inject carbon dioxide into the homogenizing section of the extruder to diffuse the carbon dioxide into the melt; after the melt is extruded into a film, it is cooled, shaped and wound to obtain a temperature-controlled bubble film.

[0038] The mixing temperature was 170°C, the rotor speed was 60 r / min, the extruder temperature was 170°C in the melting section, 155°C in the homogenizing section, and 168°C in the die section. The melt pressure was 20 MPa, and the injection flow rate of the CO2 high-pressure metering pump was controlled at 0.6 kg / h. The injection gas pressure of the high-pressure metering pump was controlled to be 0.35 MPa higher than the melt pressure.

[0039] Example 2 A temperature-controlled bubble film A temperature-controlled bubble greenhouse film, the preparation raw materials of which include, in parts by weight, 65 parts of modified EVOH, 24 parts of foam-stabilizing masterbatch, 10 parts of linear low-density polyethylene, 3 parts of polyethylene glycol, 12 parts of maleic anhydride grafted polypropylene, 3 parts of stearic acid diglyceride, and 3 parts of dioctyl phthalate.

[0040] The modified EVOH is prepared by using raw materials including, by weight, 90 parts of ethylene-vinyl alcohol copolymer, 5 parts of isobornyl methacrylate, and 0.2 parts of tert-butyl perbenzoate.

[0041] The foam stabilizing masterbatch is prepared from the following raw materials in parts by weight: 22 parts of EVA resin particles, 9 parts of polyether-modified polydimethylsiloxane, 0.8 parts of hydroxypropyl methylcellulose, 3 parts of nano-calcium carbonate, 1 part of nano-titanium dioxide, and 8 parts of maleic anhydride-grafted polyethylene.

[0042] A method for preparing a temperature-controlled bubble greenhouse film comprises the following steps: Step 1: Preparation of modified EVOH EVOH and isobornyl methacrylate were added to xylene, the air in the reactor was replaced with nitrogen, the temperature was raised to 90°C, and the mixture was stirred until completely dissolved. The system was then heated to 150°C, and tert-butyl perbenzoate was added and reacted for 60 minutes. After reacting for 60 minutes, the temperature was naturally lowered to below 40°C, and the cooled reaction solution was slowly added dropwise to a 0°C ethanol solution while stirring. After the addition was completed, stirring was continued for 30 minutes, and the solid was retained by filtration. The solid was vacuum dried at 80°C for 12 hours to obtain modified EVOH.

[0043] Both xylene and ethanol solution are used as solvents and do not participate in the reaction. The amount of xylene used is the same as that of EVOH, the amount of ethanol solution used is 5 times that of xylene, and the mass concentration of ethanol solution is 80%.

[0044] Step 2: Prepare foam-stabilizing masterbatch EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate and nano-titanium dioxide are mixed evenly, added into a twin-screw extruder for mixing and extrusion, and pelletized through water-cooled strands to obtain a foam-stabilizing masterbatch with a diameter of 2 mm.

[0045] The mixing temperature was 150°C, the screw speed was 150 r / min, and the water cooling temperature was 25±5°C.

[0046] Step 3: Foam extrusion Add modified EVOH, foam-stabilizing masterbatch, linear low-density polyethylene, polyethylene glycol, maleic anhydride grafted polypropylene, stearic acid diglyceride and dioctyl phthalate into a banbury mixer and knead for 30-45 minutes; transfer the melt obtained by banburying to a twin-screw extruder; start the high-pressure metering pump to pressurize CO2, open the CO2 injection valve, and inject carbon dioxide into the homogenizing section of the extruder to diffuse the carbon dioxide into the melt; after the melt is extruded into a film, it is cooled, shaped and wound to obtain a temperature-controlled bubble film.

[0047] The mixing temperature was 160°C, the rotor speed was 60 r / min, the extruder temperature was 165°C in the melting section, 160°C in the homogenizing section, 162°C in the die section, the melt pressure was 22 MPa, and the injection flow rate of the CO2 high-pressure metering pump was controlled at 0.6 kg / h. The injection gas pressure of the high-pressure metering pump was controlled to be 0.48 MPa higher than the melt pressure.

[0048] Example 3: A temperature-controlled bubble film A temperature-controlled bubble greenhouse film, the preparation raw materials of which include, by weight, 79 parts of modified EVOH, 16 parts of foam-stabilizing masterbatch, 10 parts of linear low-density polyethylene, 2 parts of polyethylene glycol, 20 parts of maleic anhydride grafted polypropylene, 5 parts of stearic acid diglyceride, and 3 parts of dioctyl phthalate.

[0049] The modified EVOH is prepared by using raw materials including, by weight, 100 parts of ethylene-vinyl alcohol copolymer, 8 parts of isobornyl methacrylate, and 0.3 parts of tert-butyl perbenzoate.

[0050] The foam stabilizing masterbatch is prepared from the following raw materials in parts by weight: 25 parts of EVA resin particles, 6 parts of polyether-modified polydimethylsiloxane, 2 parts of hydroxypropyl methylcellulose, 5 parts of nano-calcium carbonate, 2 parts of nano-titanium dioxide, and 10 parts of maleic anhydride-grafted polyethylene.

[0051] A method for preparing a temperature-controlled bubble greenhouse film comprises the following steps: Step 1: Preparation of modified EVOH EVOH and isobornyl methacrylate were added to xylene, the air in the reactor was replaced with nitrogen, the temperature was raised to 95°C, and the mixture was stirred until completely dissolved. The system was then heated to 160°C, and tert-butyl perbenzoate was added and reacted for 60 minutes. After reacting for 60 minutes, the temperature was naturally lowered to below 40°C, and the cooled reaction solution was slowly added dropwise to a 0°C ethanol solution while stirring. After the addition was completed, stirring was continued for 30 minutes, and the solid was retained by filtration. The solid was vacuum dried at 80°C for 15 hours to obtain modified EVOH.

[0052] Both xylene and ethanol solution are used as solvents and do not participate in the reaction. The amount of xylene used is the same as that of EVOH, the amount of ethanol solution used is 4 times that of xylene, and the mass concentration of ethanol solution is 95%.

[0053] Step 2: Prepare foam-stabilizing masterbatch EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate and nano-titanium dioxide are mixed evenly, added into a twin-screw extruder for mixing and extrusion, and pelletized through water-cooled strands to obtain a foam-stabilizing masterbatch with a diameter of 2 mm.

[0054] The mixing temperature was 155°C, the screw speed was 150 r / min, and the water cooling temperature was 25±5°C.

[0055] Step 3: Foam extrusion Add modified EVOH, foam-stabilizing masterbatch, linear low-density polyethylene, polyethylene glycol, maleic anhydride grafted polypropylene, stearic acid diglyceride and dioctyl phthalate into a banbury mixer and knead for 30-45 minutes; transfer the melt obtained by banburying to a twin-screw extruder; start the high-pressure metering pump to pressurize CO2, open the CO2 injection valve, and inject carbon dioxide into the homogenizing section of the extruder to diffuse the carbon dioxide into the melt; after the melt is extruded into a film, it is cooled, shaped and wound to obtain a temperature-controlled bubble film.

[0056] The mixing temperature was 180°C, the rotor speed was 80 r / min, the extruder temperature was 160°C in the melting section, 165°C in the homogenizing section, and 165°C in the die section. The melt pressure was 18 MPa, and the injection flow rate of the CO2 high-pressure metering pump was controlled at 0.8 kg / h. The injection gas pressure of the high-pressure metering pump was controlled to be 0.56 MPa higher than the melt pressure.

[0057] Performance Testing The temperature-controlled bubble greenhouse films obtained in Examples 1 to 3 were tested using the following method. The test results are shown in Table 1.

[0058] Mechanical properties: Based on the performance test method in GB / T4455-2019, the tensile strength, elongation at break and right-angle tear strength of the greenhouse film are tested.

[0059] Low temperature performance retention rate: adjust the steel sheet at -30℃ for 720h, test the mechanical properties at -30℃, and calculate the retention rate.

[0060] Infrared rejection rate: LS182 optical transmittance meter is used to test the 940nm infrared rejection rate.

[0061] Table 1 Performance test results

[0062] The data in Table 1 show that the temperature-controlled bubble greenhouse film provided by the present invention has a right-angle tear strength of 131-144 MPa, a tensile strength of 36.9-38.7 MPa, and an elongation at break of 282-302%. Its angle tear strength retention at -30°C is 98.3-99.5%, and its -30°C tensile strength retention is 98.6-99.3%, demonstrating good strength and low-temperature performance retention. The temperature-controlled bubble greenhouse film provided by the present invention has an infrared rejection rate of 92.9-95.5%, demonstrating excellent thermal insulation and temperature control.

[0063] The modified EVOH obtained in the step of "preparing modified EVOH" of the present invention can be confirmed by infrared spectroscopy (FTIR). Figure 2 This is the spectrum of modified EVOH. Figure 1 , 1724cm -1 Characteristic peak of ester stretching vibration, 1379 cm -1 The characteristic peaks of tertiary carbon vibration of isobornyl ester group indicate that IBMA ester group and alicyclic structure are grafted onto EVOH molecular chain to obtain modified EVOH.

[0064] Obviously, there are many specific implementation methods that can be changed under the concept of the present invention. It should be stated here that any changes made under the inventive concept of the present invention will fall within the scope of protection of the present invention.

Claims

1. A temperature-controlled bubble film, characterized in that: The bubble greenhouse film is prepared by raw materials including, by weight: 65-79 parts of modified EVOH, 16-24 parts of foam stabilizing masterbatch, 10-17 parts of linear low-density polyethylene, 2-6 parts of polyethylene glycol, 12-20 parts of maleic anhydride grafted polypropylene, 2-5 parts of stearic acid diglyceride, and 3-7 parts of dioctyl phthalate; The modified EVOH is prepared from raw materials including ethylene-vinyl alcohol copolymer, isobornyl methacrylate, and tert-butyl perbenzoate; The foam stabilizing masterbatch is prepared from raw materials including EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate, nano-titanium dioxide, and maleic anhydride-grafted polyethylene.

2. The temperature-controlled bubble film according to claim 1, characterized in that: The mass ratio of the ethylene-vinyl alcohol copolymer, isobornyl methacrylate and tert-butyl perbenzoate is (90-105): (5-10): (0.2-0.5).

3. The temperature-controlled bubble film according to claim 1, characterized in that: The mass ratio of the EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate, nano-titanium dioxide, and maleic anhydride-grafted polyethylene is (22-25): (6-9): (0.8-2): (3-5): (1-2): (8-12).

4. The method for preparing a temperature-controlled bubble greenhouse film according to any one of claims 1 to 3, wherein: The method comprises the steps of preparing modified EVOH, preparing foam-stabilizing masterbatch, and foaming extrusion. The method comprises the following steps: adding ethylene-vinyl alcohol copolymer and isobornyl methacrylate into xylene, replacing the air in the reactor with nitrogen, heating the reactor to 90-95°C, stirring the reactor until the reactor is completely dissolved, heating the reactor to 150-160°C, adding tert-butyl perbenzoate to react, dripping the reaction solution into a 0°C ethanol solution, stirring the solution, and filtering the solution to retain the solid.

5. The method for preparing a temperature-controlled bubble greenhouse film according to claim 4, wherein: The amount of xylene used is the same as the weight of the ethylene-vinyl alcohol copolymer; the mass concentration of the ethanol solution is 50-95%, and the amount used is 4-5 times the mass of xylene.

6. The method for preparing a temperature-controlled bubble greenhouse film according to claim 4, wherein: The foam stabilizing masterbatch is prepared by mixing EVA resin particles, polyether-modified polydimethylsiloxane, hydroxypropyl methylcellulose, nano-calcium carbonate and nano-titanium dioxide, kneading and extruding, and water-cooling and pelletizing.

7. The method for preparing a temperature-controlled bubble greenhouse film according to claim 6, wherein: The mixing and extrusion process includes a mixing temperature of 145-155° C. and a screw speed of 150-200 r / min.

8. The method for preparing a temperature-controlled bubble greenhouse film according to claim 4, wherein: The foaming extrusion comprises the following steps: adding modified EVOH, foam stabilizing masterbatch, linear low-density polyethylene, polyethylene glycol, maleic anhydride grafted polypropylene, diglycerol stearate, and dioctyl phthalate into an internal mixer for internal mixing; transferring the melt obtained by internal mixing to an extrusion device; starting a high-pressure metering pump to pressurize the melt and inject CO2; and after the melt is extruded into a film, cooling and shaping the film and winding the film.

9. The method for preparing a temperature-controlled bubble greenhouse film according to claim 8, wherein: The banburying time is 30-45 min, the banburying temperature is 160-180° C., and the rotor speed is 60-80 r / min.

10. The method for preparing a temperature-controlled bubble greenhouse film according to claim 8, wherein: In the pressurized injection, the pressure of the gas injected by the high-pressure metering pump is 0.35-0.56 MPa higher than the melt pressure, and the flow rate of the high-pressure metering pump is controlled at 0.6-0.8 kg / h.

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