Anti-dripping ETFE film for greenhouse and preparation method of anti-dripping ETFE film

Abstract

The invention belongs to the technical field of ETFE film preparation, and particularly relates to an anti-dripping and anti-dew ETFE film for a greenhouse and a preparation method of the anti-dripping and anti-dew ETFE film. The ETFE film is composed of an outer layer, a middle layer and an inner layer, and the outer layer is prepared from ETFE resin, tetrafluoroethylene, a terpolymer of hexafluoropropylene and vinylidene fluoride, perfluoroalkyl ethyl methacrylate, an antioxidant, a hindered amine light stabilizer and an ultraviolet light absorber; the middle layer is prepared from the following raw materials: ETFE resin, tetrafluoroethylene, a terpolymer of hexafluoropropylene and vinylidene fluoride, and anti-dripping and anti-dew master batch; and the inner layer is prepared from the following raw materials: ETFE resin, anti-dripping master batch, an ultraviolet light absorber and a hindered amine light stabilizer. The three layers have a synergistic effect, so that the prepared ETFE film has excellent mechanical strength, weather resistance, dripping and dew prevention performance and high light transmission, the requirement of long-term outdoor use of a greenhouse film can be met, and the illumination condition required by crop growth and the stability of the environment in a greenhouse are considered.

Description

Technical Field

[0001] This invention belongs to the field of ETFE film preparation technology, specifically relating to an anti-drip ETFE film for greenhouses and its preparation method. Background Technology

[0002] ETFE (ethylene-tetrafluoroethylene copolymer) membrane, as a high-performance fluoropolymer material, is widely used in high-end construction and agriculture due to its excellent comprehensive properties. Currently, commercially available ETFE membranes typically exhibit the following characteristics: ① excellent optical properties; ② outstanding weather resistance; ③ good mechanical strength, tear resistance, and chemical stability. Furthermore, ETFE membranes have an extremely wide operating temperature range (-200~150℃) and a melting point of around 275℃, enabling them to adapt to various harsh climatic conditions.

[0003] Despite the numerous advantages of ETFE films, their direct application in agricultural greenhouses reveals a series of problems, primarily in the following aspects: ① Condensation: Inside agricultural greenhouses, humidity is typically high due to plant transpiration and temperature differences. When water vapor cools on the inner surface of the film, it easily reaches its dew point and condenses into water droplets. Traditional ETFE films lack sufficient hydrophilic or hydrophobic regulation, leading to the formation of numerous discrete water droplets rather than a uniform water film. These droplets not only refract and scatter light, reducing light transmittance and affecting crop photosynthesis, but also accumulate and drip, causing mechanical damage to delicate crops and creating a microenvironment conducive to pathogen growth. ② Functional limitation: Existing ETFE film technologies often focus on improving a single performance characteristic. For example, the ETFE fluoropolymer film disclosed in CN119388811A focuses on reducing surface water accumulation and improving self-cleaning performance through a wear-resistant hydrophobic layer; the cross-linked ETFE composite film disclosed in CN120552452B focuses on constructing a gradient UV shielding function to achieve high light transmittance and full-band UV shielding. However, these technologies have not systematically solved the problem of anti-drip on the inner surface in greenhouse applications. ③ Balancing long-term anti-drip and light transmittance: Some studies have attempted to impart anti-drip function to ETFE films through surface coatings, but these often suffer from poor coating durability, easy aging and peeling, and problems such as affecting the light transmittance of the base film or increasing haze. For example, ordinary hydrophilic coatings may fail due to ultraviolet radiation or humid and hot environments after long-term use, and may increase film haze, affecting direct light penetration.

[0004] In conclusion, developing a specialized ETFE greenhouse film that combines high efficiency in preventing dripping, high light transmittance, and controllable cost has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-drip ETFE film for greenhouses, which has good mechanical properties, anti-drip performance and high light transmittance. In addition, this invention also provides a method for its preparation.

[0006] The ETFE anti-drip film for greenhouses described in this invention comprises an outer layer, a middle layer, and an inner layer. The outer layer, by weight, consists of the following raw materials: 100 parts ETFE resin, 4-5 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, 2.0-2.2 parts perfluoroalkyl ethyl methacrylate, 0.26-0.28 parts antioxidant, 0.28-0.30 parts hindered amine light stabilizer, and 0.28-... 0.30 parts; the intermediate layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 6-8 parts terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, and 19-20 parts anti-drip masterbatch; the inner layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 10-11 parts anti-drip masterbatch, 0.8-1.0 parts ultraviolet absorber, and 0.28-0.30 parts hindered amine light stabilizer.

[0007] Among them, the thickness of the anti-drip ETFE film for greenhouses is 200 micrometers, and the thickness ratio of the outer layer, middle layer and inner layer is 1:2:1.

[0008] The CAS number for the perfluoroalkyl ethyl methacrylate in the outer layer is 65530-66-7.

[0009] The hindered amine light stabilizer in both the outer and inner layers is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0010] The ultraviolet absorber in both the outer and inner layers is Tinuvin 1577, an ultraviolet absorber manufactured by BASF.

[0011] The antioxidant in the outer layer is a mixture of antioxidant 1010 and antioxidant 168, with a mass ratio of antioxidant 1010 to antioxidant 168 of 1:1.

[0012] The intermediate layer and the inner layer contain the same anti-drip masterbatch. The preparation method of the anti-drip masterbatch consists of the following steps: ETFE resin, anti-drip filler, antioxidant 1010, antioxidant 168 and hindered amine light stabilizer are added to a mixer and mixed for 5 minutes. Then the mixture is added to a twin-screw extruder for melt extrusion. After filtration, underwater pelletizing, drying and sieving, the anti-drip masterbatch is obtained.

[0013] In the preparation method of the anti-drip masterbatch, the mixing speed is 1000 r / min, the mixing temperature is room temperature, and the melt extrusion temperature is 285-287℃.

[0014] In the preparation method of anti-drip masterbatch, the underwater pelleting temperature is 70-73℃, resulting in particles with a diameter of 2mm.

[0015] In the preparation method of anti-drip masterbatch, the drying temperature is 80-85℃, the drying time is 30min, and it is passed through an 8-mesh sieve.

[0016] The anti-drip masterbatch is composed of the following raw materials by mass: 100 parts ETFE resin, 10-12 parts anti-drip filler, 0.18-0.2 parts antioxidant 1010, 0.18-0.2 parts antioxidant 168, and 0.25-0.27 parts hindered amine light stabilizer. The hindered amine light stabilizer is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0017] The preparation method of the anti-drip filler consists of the following steps: ① Preparation of pretreated nano-sepiolite: The nano-sepiolite is dehydrated to obtain dried nano-sepiolite. The dried nano-sepiolite powder is added to 2.5% hydrochloric acid by mass concentration and magnetically stirred. After the reaction is completed, it is filtered, washed with deionized water, and vacuum dried to obtain pretreated nano-sepiolite; ② Preparation of pretreated magnesium borate whiskers: The magnesium borate whiskers are vacuum dried at 80℃ for 2 hours; ③ Preparation of pretreated zinc gallate nano-gallate: The zinc gallate nano-gallate is vacuum dried at 80℃ for 4 hours; ④ Anhydrous ethanol and deionized water are mixed evenly at a volume ratio of 95:5, and then KH-560 is added. The silane coupling agent was mixed to achieve a mass concentration of 2% for KH-560 silane coupling agent. Finally, glacial acetic acid was added to adjust the pH of the system to 4.5. The mixture was hydrolyzed at room temperature for 10 min to prepare a pre-hydrolyzed solution. ⑤ Pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate were added to the pre-hydrolyzed solution and magnetically stirred at room temperature for 30 min. Then, nitrogen gas was purged for 30 min, and the temperature was raised to 64℃ for reflux reaction for 2 h. ⑥ After the reflux reaction was completed, the mixture was naturally cooled to 40℃, the nitrogen gas was turned off, the reaction mixture was vacuum filtered, the filter cake was collected, and the filter cake was washed three times with anhydrous ethanol. Then, it was vacuum dried and sieved to prepare an anti-drip packing.

[0018] In step ①, the dehydration treatment temperature for preparing nano-sepiolite is 80℃, the dehydration treatment pressure is -0.09MPa, and the dehydration treatment time is 4h.

[0019] In step ①, the mass ratio of hydrochloric acid to dried nano-sepiolite in the preparation method is 5:1, the magnetic stirring reaction time is 1.5h, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, and the vacuum drying pressure is -0.09MPa.

[0020] In step ⑤, the mass ratio of pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate is 6:3:2.

[0021] In step ⑤, the mass ratio of the pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate to the pre-hydrolyzed solution is 1:5.

[0022] In step ⑥, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, the vacuum drying pressure is -0.09MPa, and it is passed through a 200-mesh sieve.

[0023] The method for preparing the anti-drip ETFE film for greenhouses according to the present invention comprises the following steps: (1) Add the outer layer raw material, the middle layer raw material and the inner layer raw material into a high-speed mixer for mixing. After mixing evenly, the outer layer mixture, the middle layer mixture and the inner layer mixture are discharged. (2) The outer layer mixture, the middle layer mixture and the inner layer mixture are respectively added to a three-layer co-extrusion blown film machine for blown film forming, and then cooled, shaped, pulled and wound to prepare a greenhouse anti-drip ETFE film.

[0024] In step (1), the parameters for mixing the outer layer, the middle layer and the inner layer are the same, the temperature during mixing is room temperature, the speed during mixing is 1000 r / min and the mixing time is 5 min.

[0025] Step (2) The temperature of the feeding section of the three-layer co-extrusion blown film machine is 253-255℃, the temperature of the compression section is 270-275℃, the temperature of the melting section is 285-288℃, the temperature of the homogenization section is 280-283℃, and the temperature of the die head is 275-278℃.

[0026] In step (2), the three-layer melt is extruded through a three-layer co-extrusion die, and the blow-up ratio is controlled to be 1.8 and the traction ratio is 3.0.

[0027] In step (2), the temperature of the air ring during cooling and shaping is controlled at 23℃, and the traction speed is 22m / min.

[0028] Compared with the prior art, the present invention has the following advantages: (1) The ETFE film for greenhouses described in this invention consists of an outer layer, a middle layer, and an inner layer. The outer layer provides wear resistance and self-cleaning, the middle layer provides mechanical reinforcement and anti-drip properties, and the inner layer enhances surface hydrophilicity and UV shielding with almost no impact on light transmittance. Thus, the three layers work synergistically to ensure that the prepared ETFE film has excellent mechanical strength, weather resistance, anti-drip properties, and high light transmittance, which can meet the needs of long-term outdoor use of greenhouse films, while taking into account the light conditions required for crop growth and the stability of the greenhouse environment.

[0029] (2) The ETFE film for greenhouse anti-drip in the present invention, wherein the outer layer is made of ETFE resin as the main matrix resin, and a terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride is added to improve the wear resistance of the outer layer. The terpolymer of perfluoroalkyl ethyl methacrylate and tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride works synergistically to increase the contact angle, so that the outer layer has self-cleaning properties. The addition of antioxidants, hindered amine light stabilizers and ultraviolet absorbers gives the outer layer excellent weather resistance and extends the service life of the ETFE film.

[0030] (3) The anti-drip ETFE film for greenhouses described in this invention comprises an intermediate layer mainly composed of ETFE resin, with the addition of a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride to improve the mechanical strength and melt processing fluidity of the intermediate layer. A high proportion of anti-drip masterbatch is also added. Magnesium borate whiskers in the anti-drip filler further enhance the internal durability and mechanical properties of the ETFE film, while sepiolite imparts appropriate hydrophilicity to the intermediate layer, thereby constructing continuous hydrophilic transport channels within the film and laying the core structural foundation for the anti-drip performance of the greenhouse ETFE film. This results in the formation of continuous hydrophilic channels within the prepared ETFE film, allowing water vapor from inside the greenhouse to permeate into the hydrophilic area of ​​the film, forming a uniform water film that flows down the inner surface of the film, preventing condensation into water droplets.

[0031] (4) The anti-drip ETFE film for greenhouses described in this invention uses ETFE resin as the base resin in the inner layer, and combines anti-drip masterbatch, ultraviolet absorber, and hindered amine light stabilizer. The sepiolite in the anti-drip masterbatch gives the ETFE film lasting hydrophilicity, allowing condensate on its inner surface to spread evenly to form a thin water film instead of discrete water droplets, thereby preventing the formation of dripping water droplets. The ultraviolet absorber and hindered amine light stabilizer work synergistically to improve the UV resistance of the inner layer without affecting the light transmittance. While achieving the anti-drip function, the inherent high light transmittance of the ETFE film is maintained, ensuring the photosynthetically active light flux required by crops and avoiding damage to crops from ultraviolet light.

[0032] (5) The anti-drip ETFE membrane for greenhouses described in this invention, wherein the anti-drip masterbatch uses ETFE resin as the main resin and adds anti-drip filler, antioxidant 1010, antioxidant 168 and hindered amine light stabilizer. The anti-drip filler is composed of pretreated nano sepiolite, pretreated magnesium borate whiskers and pretreated nano zinc gallate. After being pretreated by dilute hydrochloric acid etching and vacuum drying, the surface hydroxyl content of the pretreated nano sepiolite is greatly increased, and its hydrophilicity is significantly enhanced. It can construct continuous hydrophilic channels in the ETFE matrix and is the core functional component for the anti-drip performance of the membrane material. At the same time, its nano-layered structure can help improve the mechanical properties and dimensional stability of the masterbatch. After the pretreated magnesium borate whiskers are vacuum dried to remove surface free water, their dispersibility is better. Their high aspect ratio needle-like structure can form an interwoven mechanical reinforcement network in the ETFE matrix, significantly improving the tensile strength and elongation at break of the anti-drip masterbatch and membrane material, providing stable mechanical skeleton support for the membrane material. After vacuum drying pretreatment, the agglomeration of pretreated nano zinc gallate is suppressed. It has good UV shielding ability and can work synergistically with the UV absorbers in the outer and inner layers of the membrane to further broaden the UV shielding band and improve the overall UV aging resistance of the membrane. At the same time, its nano-sized particle size has little impact on the light transmittance of the membrane, which can meet both UV protection and crop photosynthetic needs.

[0033] (6) The preparation method of the anti-drip ETFE film for greenhouses described in this invention has a short process chain, easy process parameters are easy to control, and easy to realize industrial production. Detailed Implementation

[0034] Example 1 The ETFE anti-drip film for greenhouses described in Example 1 comprises an outer layer, a middle layer, and an inner layer. The outer layer, by weight, consists of the following raw materials: 100 parts ETFE resin, 4.5 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, 2.1 parts perfluoroalkyl ethyl methacrylate, 0.27 parts antioxidant, 0.29 parts hindered amine light stabilizer, and 0.29 parts ultraviolet absorber. The middle layer, by weight, consists of the following raw materials: 100 parts ETFE resin, 7 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, and 19.5 parts anti-drip masterbatch. The inner layer, by weight, consists of the following raw materials: 100 parts ETFE resin, 10.5 parts anti-drip masterbatch, 0.9 parts ultraviolet absorber, and 0.29 parts hindered amine light stabilizer.

[0035] Among them, the thickness of the anti-drip ETFE film for greenhouses is 200 micrometers, and the thickness ratio of the outer layer, middle layer and inner layer is 1:2:1.

[0036] The CAS number for the perfluoroalkyl ethyl methacrylate in the outer layer is 65530-66-7.

[0037] The hindered amine light stabilizer in both the outer and inner layers is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0038] The ultraviolet absorber in both the outer and inner layers is Tinuvin 1577, an ultraviolet absorber manufactured by BASF.

[0039] The antioxidant in the outer layer is a mixture of antioxidant 1010 and antioxidant 168, with a mass ratio of antioxidant 1010 to antioxidant 168 of 1:1.

[0040] The intermediate layer and the inner layer contain the same anti-drip masterbatch. The preparation method of the anti-drip masterbatch consists of the following steps: ETFE resin, anti-drip filler, antioxidant 1010, antioxidant 168 and hindered amine light stabilizer are added to a mixer and mixed for 5 minutes. Then the mixture is added to a twin-screw extruder for melt extrusion. After filtration, underwater pelletizing, drying and sieving, the anti-drip masterbatch is obtained.

[0041] In the preparation method of the anti-drip masterbatch, the mixing speed is 1000 r / min, the mixing temperature is room temperature, and the melt extrusion temperature is 286℃.

[0042] In the preparation method of anti-drip masterbatch, the underwater pelleting temperature is 71℃, resulting in particles with a diameter of 2mm.

[0043] In the preparation method of anti-drip masterbatch, the drying temperature is 83℃, the drying time is 30min, and it is passed through an 8-mesh sieve.

[0044] The anti-drip masterbatch is composed of the following raw materials in parts by weight: 100 parts ETFE resin, 11 parts anti-drip filler, 0.19 parts antioxidant 1010, 0.19 parts antioxidant 168, and 0.26 parts hindered amine light stabilizer. The hindered amine light stabilizer is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0045] The preparation method of the anti-drip filler consists of the following steps: ① Preparation of pretreated nano-sepiolite: The nano-sepiolite is dehydrated to obtain dried nano-sepiolite. The dried nano-sepiolite powder is added to 2.5% hydrochloric acid by mass concentration and magnetically stirred. After the reaction is completed, it is filtered, washed with deionized water, and vacuum dried to obtain pretreated nano-sepiolite; ② Preparation of pretreated magnesium borate whiskers: The magnesium borate whiskers are vacuum dried at 80℃ for 2 hours; ③ Preparation of pretreated zinc gallate nano-gallate: The zinc gallate nano-gallate is vacuum dried at 80℃ for 4 hours; ④ Anhydrous ethanol and deionized water are mixed evenly at a volume ratio of 95:5, and then KH-560 is added. The silane coupling agent was mixed to achieve a mass concentration of 2% for KH-560 silane coupling agent. Finally, glacial acetic acid was added to adjust the pH of the system to 4.5. The mixture was hydrolyzed at room temperature for 10 min to prepare a pre-hydrolyzed solution. ⑤ Pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate were added to the pre-hydrolyzed solution and magnetically stirred at room temperature for 30 min. Then, nitrogen gas was purged for 30 min, and the temperature was raised to 64℃ for reflux reaction for 2 h. ⑥ After the reflux reaction was completed, the mixture was naturally cooled to 40℃, the nitrogen gas was turned off, the reaction mixture was vacuum filtered, the filter cake was collected, and the filter cake was washed three times with anhydrous ethanol. Then, it was vacuum dried and sieved to prepare an anti-drip packing.

[0046] In step ①, the dehydration treatment temperature for preparing nano-sepiolite is 80℃, the dehydration treatment pressure is -0.09MPa, and the dehydration treatment time is 4h.

[0047] In step ①, the mass ratio of hydrochloric acid to dried nano-sepiolite in the preparation method is 5:1, the magnetic stirring reaction time is 1.5h, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, and the vacuum drying pressure is -0.09MPa.

[0048] In step ⑤, the mass ratio of pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate is 6:3:2.

[0049] In step ⑤, the mass ratio of the pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate to the pre-hydrolyzed solution is 1:5.

[0050] In step ⑥, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, the vacuum drying pressure is -0.09MPa, and it is passed through a 200-mesh sieve.

[0051] The preparation method of the anti-drip ETFE film for greenhouses described in Example 1 consists of the following steps: (1) Add the outer layer raw material, the middle layer raw material and the inner layer raw material into a high-speed mixer for mixing. After mixing evenly, the outer layer mixture, the middle layer mixture and the inner layer mixture are discharged. (2) The outer layer mixture, the middle layer mixture and the inner layer mixture are respectively added to a three-layer co-extrusion blown film machine for blown film forming, and then cooled, shaped, pulled and wound to prepare a greenhouse anti-drip ETFE film.

[0052] In step (1), the parameters for mixing the outer layer, the middle layer and the inner layer are the same, the temperature during mixing is room temperature, the speed during mixing is 1000 r / min and the mixing time is 5 min.

[0053] Step (2) The temperature of the feeding section of the three-layer co-extrusion blown film machine is 254℃, the temperature of the compression section is 273℃, the temperature of the melting section is 286℃, the temperature of the homogenization section is 281℃, and the temperature of the die head is 276℃.

[0054] In step (2), the three-layer melt is extruded through a three-layer co-extrusion die, and the blow-up ratio is controlled to be 1.8 and the traction ratio is 3.0.

[0055] In step (2), the temperature of the air ring during cooling and shaping is controlled at 23℃, and the traction speed is 22m / min.

[0056] Example 2 The ETFE anti-drip film for greenhouses described in Example 2 consists of an outer layer, a middle layer, and an inner layer. The outer layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 4 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, 2.2 parts perfluoroalkyl ethyl methacrylate, 0.26 parts antioxidant, 0.30 parts hindered amine light stabilizer, and 0.28 parts ultraviolet absorber. The middle layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 6 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, and 19 parts anti-drip masterbatch. The inner layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 11 parts anti-drip masterbatch, 0.8 parts ultraviolet absorber, and 0.30 parts hindered amine light stabilizer.

[0057] Among them, the thickness of the anti-drip ETFE film for greenhouses is 200 micrometers, and the thickness ratio of the outer layer, middle layer and inner layer is 1:2:1.

[0058] The CAS number for the perfluoroalkyl ethyl methacrylate in the outer layer is 65530-66-7.

[0059] The hindered amine light stabilizer in both the outer and inner layers is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0060] The ultraviolet absorber in both the outer and inner layers is Tinuvin 1577, an ultraviolet absorber manufactured by BASF.

[0061] The antioxidant in the outer layer is a mixture of antioxidant 1010 and antioxidant 168, with a mass ratio of antioxidant 1010 to antioxidant 168 of 1:1.

[0062] The intermediate layer and the inner layer contain the same anti-drip masterbatch. The preparation method of the anti-drip masterbatch consists of the following steps: ETFE resin, anti-drip filler, antioxidant 1010, antioxidant 168 and hindered amine light stabilizer are added to a mixer and mixed for 5 minutes. Then the mixture is added to a twin-screw extruder for melt extrusion. After filtration, underwater pelletizing, drying and sieving, the anti-drip masterbatch is obtained.

[0063] In the preparation method of the anti-drip masterbatch, the mixing speed is 1000 r / min, the mixing temperature is room temperature, and the melt extrusion temperature is 287℃.

[0064] In the preparation method of anti-drip masterbatch, the underwater pelleting temperature is 73℃, resulting in particles with a diameter of 2mm.

[0065] In the preparation method of anti-drip masterbatch, the drying temperature is 85℃, the drying time is 30min, and it is passed through an 8-mesh sieve.

[0066] The anti-drip masterbatch is composed of the following raw materials by mass: 100 parts ETFE resin, 10 parts anti-drip filler, 0.18 parts antioxidant 1010, 0.18 parts antioxidant 168, and 0.27 parts hindered amine light stabilizer. The hindered amine light stabilizer is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0067] The preparation method of the anti-drip filler consists of the following steps: ① Preparation of pretreated nano-sepiolite: The nano-sepiolite is dehydrated to obtain dried nano-sepiolite. The dried nano-sepiolite powder is added to 2.5% hydrochloric acid by mass concentration and magnetically stirred. After the reaction is completed, it is filtered, washed with deionized water, and vacuum dried to obtain pretreated nano-sepiolite; ② Preparation of pretreated magnesium borate whiskers: The magnesium borate whiskers are vacuum dried at 80℃ for 2 hours; ③ Preparation of pretreated zinc gallate nano-gallate: The zinc gallate nano-gallate is vacuum dried at 80℃ for 4 hours; ④ Anhydrous ethanol and deionized water are mixed evenly at a volume ratio of 95:5, and then KH-560 is added. The silane coupling agent was mixed to achieve a mass concentration of 2% for KH-560 silane coupling agent. Finally, glacial acetic acid was added to adjust the pH of the system to 4.5. The mixture was hydrolyzed at room temperature for 10 min to prepare a pre-hydrolyzed solution. ⑤ Pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate were added to the pre-hydrolyzed solution and magnetically stirred at room temperature for 30 min. Then, nitrogen gas was purged for 30 min, and the temperature was raised to 64℃ for reflux reaction for 2 h. ⑥ After the reflux reaction was completed, the mixture was naturally cooled to 40℃, the nitrogen gas was turned off, the reaction mixture was vacuum filtered, the filter cake was collected, and the filter cake was washed three times with anhydrous ethanol. Then, it was vacuum dried and sieved to prepare an anti-drip packing.

[0068] In step ①, the dehydration treatment temperature for preparing nano-sepiolite is 80℃, the dehydration treatment pressure is -0.09MPa, and the dehydration treatment time is 4h.

[0069] In step ①, the mass ratio of hydrochloric acid to dried nano-sepiolite in the preparation method is 5:1, the magnetic stirring reaction time is 1.5h, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, and the vacuum drying pressure is -0.09MPa.

[0070] In step ⑤, the mass ratio of pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate is 6:3:2.

[0071] In step ⑤, the mass ratio of the pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate to the pre-hydrolyzed solution is 1:5.

[0072] In step ⑥, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, the vacuum drying pressure is -0.09MPa, and it is passed through a 200-mesh sieve.

[0073] The preparation method of the anti-drip ETFE film for greenhouses described in Example 2 consists of the following steps: (1) Add the outer layer raw material, the middle layer raw material and the inner layer raw material into a high-speed mixer for mixing. After mixing evenly, the outer layer mixture, the middle layer mixture and the inner layer mixture are discharged. (2) The outer layer mixture, the middle layer mixture and the inner layer mixture are respectively added to a three-layer co-extrusion blown film machine for blown film forming, and then cooled, shaped, pulled and wound to prepare a greenhouse anti-drip ETFE film.

[0074] In step (1), the parameters for mixing the outer layer, the middle layer and the inner layer are the same, the temperature during mixing is room temperature, the speed during mixing is 1000 r / min and the mixing time is 5 min.

[0075] Step (2) The temperature of the feeding section of the three-layer co-extrusion blown film machine is 255℃, the temperature of the compression section is 275℃, the temperature of the melting section is 288℃, the temperature of the homogenization section is 283℃, and the temperature of the die head is 278℃.

[0076] In step (2), the three-layer melt is extruded through a three-layer co-extrusion die, and the blow-up ratio is controlled to be 1.8 and the traction ratio is 3.0.

[0077] In step (2), the temperature of the air ring during cooling and shaping is controlled at 23℃, and the traction speed is 22m / min.

[0078] Example 3 The ETFE anti-drip film for greenhouses described in Example 3 consists of an outer layer, a middle layer, and an inner layer. The outer layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 5 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, 2.0 parts perfluoroalkyl ethyl methacrylate, 0.28 parts antioxidant, 0.28 parts hindered amine light stabilizer, and 0.30 parts ultraviolet absorber. The middle layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 8 parts a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride, and 20 parts anti-drip masterbatch. The inner layer, by weight, is composed of the following raw materials: 100 parts ETFE resin, 10 parts anti-drip masterbatch, 1.0 part ultraviolet absorber, and 0.28 parts hindered amine light stabilizer.

[0079] Among them, the thickness of the anti-drip ETFE film for greenhouses is 200 micrometers, and the thickness ratio of the outer layer, middle layer and inner layer is 1:2:1.

[0080] The CAS number for the perfluoroalkyl ethyl methacrylate in the outer layer is 65530-66-7.

[0081] The hindered amine light stabilizer in both the outer and inner layers is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0082] The ultraviolet absorber in both the outer and inner layers is Tinuvin 1577, an ultraviolet absorber manufactured by BASF.

[0083] The antioxidant in the outer layer is a mixture of antioxidant 1010 and antioxidant 168, with a mass ratio of antioxidant 1010 to antioxidant 168 of 1:1.

[0084] The intermediate layer and the inner layer contain the same anti-drip masterbatch. The preparation method of the anti-drip masterbatch consists of the following steps: ETFE resin, anti-drip filler, antioxidant 1010, antioxidant 168 and hindered amine light stabilizer are added to a mixer and mixed for 5 minutes. Then the mixture is added to a twin-screw extruder for melt extrusion. After filtration, underwater pelletizing, drying and sieving, the anti-drip masterbatch is obtained.

[0085] In the preparation method of the anti-drip masterbatch, the mixing speed is 1000 r / min, the mixing temperature is room temperature, and the melt extrusion temperature is 285℃.

[0086] In the preparation method of anti-drip masterbatch, the underwater pelleting temperature is 70℃, resulting in particles with a diameter of 2mm.

[0087] In the preparation method of anti-drip masterbatch, the drying temperature is 80℃, the drying time is 30min, and it is passed through an 8-mesh sieve.

[0088] The anti-drip masterbatch is composed of the following raw materials by mass: 100 parts ETFE resin, 12 parts anti-drip filler, 0.2 parts antioxidant 1010, 0.2 parts antioxidant 168, and 0.25 parts hindered amine light stabilizer. The hindered amine light stabilizer is light stabilizer XT-8, manufactured by Beijing Tiangang Additives Co., Ltd.

[0089] The preparation method of the anti-drip filler consists of the following steps: ① Preparation of pretreated nano-sepiolite: The nano-sepiolite is dehydrated to obtain dried nano-sepiolite. The dried nano-sepiolite powder is added to 2.5% hydrochloric acid by mass concentration and magnetically stirred. After the reaction is completed, it is filtered, washed with deionized water, and vacuum dried to obtain pretreated nano-sepiolite; ② Preparation of pretreated magnesium borate whiskers: The magnesium borate whiskers are vacuum dried at 80℃ for 2 hours; ③ Preparation of pretreated zinc gallate nano-gallate: The zinc gallate nano-gallate is vacuum dried at 80℃ for 4 hours; ④ Anhydrous ethanol and deionized water are mixed evenly at a volume ratio of 95:5, and then KH-560 is added. The silane coupling agent was mixed to achieve a mass concentration of 2% for KH-560 silane coupling agent. Finally, glacial acetic acid was added to adjust the pH of the system to 4.5. The mixture was hydrolyzed at room temperature for 10 min to prepare a pre-hydrolyzed solution. ⑤ Pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate were added to the pre-hydrolyzed solution and magnetically stirred at room temperature for 30 min. Then, nitrogen gas was purged for 30 min, and the temperature was raised to 64℃ for reflux reaction for 2 h. ⑥ After the reflux reaction was completed, the mixture was naturally cooled to 40℃, the nitrogen gas was turned off, the reaction mixture was vacuum filtered, the filter cake was collected, and the filter cake was washed three times with anhydrous ethanol. Then, it was vacuum dried and sieved to prepare an anti-drip packing.

[0090] In step ①, the dehydration treatment temperature for preparing nano-sepiolite is 80℃, the dehydration treatment pressure is -0.09MPa, and the dehydration treatment time is 4h.

[0091] In step ①, the mass ratio of hydrochloric acid to dried nano-sepiolite in the preparation method is 5:1, the magnetic stirring reaction time is 1.5h, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, and the vacuum drying pressure is -0.09MPa.

[0092] In step ⑤, the mass ratio of pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate is 6:3:2.

[0093] In step ⑤, the mass ratio of the pretreated nano-sepiolite, pretreated magnesium borate whiskers, and pretreated nano-zinc gallate to the pre-hydrolyzed solution is 1:5.

[0094] In step ⑥, the vacuum drying temperature is 80℃, the vacuum drying time is 2h, the vacuum drying pressure is -0.09MPa, and it is passed through a 200-mesh sieve.

[0095] The preparation method of the anti-drip ETFE film for greenhouses described in Example 3 consists of the following steps: (1) Add the outer layer raw material, the middle layer raw material and the inner layer raw material into a high-speed mixer for mixing. After mixing evenly, the outer layer mixture, the middle layer mixture and the inner layer mixture are discharged. (2) The outer layer mixture, the middle layer mixture and the inner layer mixture are respectively added to a three-layer co-extrusion blown film machine for blown film forming, and then cooled, shaped, pulled and wound to prepare a greenhouse anti-drip ETFE film.

[0096] In step (1), the parameters for mixing the outer layer, the middle layer and the inner layer are the same, the temperature during mixing is room temperature, the speed during mixing is 1000 r / min and the mixing time is 5 min.

[0097] Step (2) The temperature of the feeding section of the three-layer co-extrusion blown film machine is 253℃, the temperature of the compression section is 270℃, the temperature of the melting section is 285℃, the temperature of the homogenization section is 280℃, and the temperature of the die head is 275℃.

[0098] In step (2), the three-layer melt is extruded through a three-layer co-extrusion die, and the blow-up ratio is controlled to be 1.8 and the traction ratio is 3.0.

[0099] In step (2), the temperature of the air ring during cooling and shaping is controlled at 23℃, and the traction speed is 22m / min.

[0100] Comparative Example 1 The preparation method of the anti-drip ETFE film for greenhouses described in Comparative Example 1 is the same as that in Example 1, and the raw material composition of the outer and inner layers is also the same as that in Example 1. The only difference is that no anti-drip masterbatch is added to the middle layer.

[0101] Comparative Example 2 The preparation method of the anti-drip ETFE film for greenhouses described in Comparative Example 2 is the same as that in Example 1, and the raw material composition of the outer and middle layers is also the same as that in Example 1. The only difference is that no anti-drip masterbatch is added to the inner layer.

[0102] The performance of the anti-drip ETFE films for greenhouses prepared in Examples 1-3 and Comparative Examples 1-2 was tested, and the results are shown in Table 1 below. Tensile strength and elongation at break were tested according to GB / T 1040.3; the outer and inner contact angles of the ETFE film were tested according to GB / T 30693 (static contact angle); light transmittance was tested according to GB / T 2410; aging resistance was tested according to GB / T 16422.2; and anti-drip performance was tested according to NY / T 1452-2007. The results are shown in Table 1 below. Table 1 Performance test results of anti-drip ETFE film for greenhouses

[0103] As shown in Table 1, the mechanical strength of the ETFE films prepared in Examples 1-3 is greater than that in Comparative Examples 1-2. The outer contact angle indicates that the outer layer of the ETFE films prepared in Examples 1-3 and Comparative Examples 1-2 has strong hydrophobicity, enabling self-cleaning. The inner contact angle of the ETFE films prepared in Examples 1-3 is much smaller than that in Comparative Examples 1-2, indicating good hydrophilicity on the inner side. The light transmittance of the ETFE films prepared in Examples 1-3 and Comparative Examples 1-2 is similar. The retention rates of tensile strength and elongation at break of the ETFE films prepared in Examples 1-3 are much better than those in Comparative Examples 1-2, indicating that the aging resistance of the ETFE films prepared in Examples 1-3 is superior to that in Comparative Examples 1-2. The dew drop retention rate of the ETFE films prepared in Examples 1-3 is much lower than that in Comparative Examples 1-2, further demonstrating that the ETFE films prepared in Examples 1-3 have excellent anti-drip properties.

[0104] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A drip-proof ETFE film for a greenhouse, characterized by: The outer layer, the intermediate layer and the inner layer are composed of the following raw materials in parts by weight: 100 parts of ETFE resin, 4-5 parts of terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, 2.0-2.2 parts of perfluoroalkylethyl methacrylate, 0.26-0.28 parts of antioxidant, 0.28-0.30 parts of hindered amine light stabilizer and 0.28-0.30 parts of ultraviolet absorber; the intermediate layer is composed of the following raw materials in parts by weight: 100 parts of ETFE resin, 6-8 parts of terpolymer of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride and 19-20 parts of anti-dew drop master batch; and the inner layer is composed of the following raw materials in parts by weight: 100 parts of ETFE resin, 10-11 parts of anti-dew drop master batch, 0.8-1.0 parts of ultraviolet absorber and 0.28-0.30 parts of hindered amine light stabilizer.

2. The anti-dripping ETFE film for a greenhouse according to claim 1, characterized by: The thickness of the anti-dew drop ETFE film for greenhouse is 200 microns, and the thickness ratio of the outer layer, the intermediate layer and the inner layer is 1:2:1; The hindered amine light stabilizer in the outer layer and the inner layer is light stabilizer XT-8; The ultraviolet absorber in the outer layer and the inner layer is ultraviolet absorber Tinuvin 1577; The antioxidant in the outer layer is a mixture of antioxidant 1010 and antioxidant 168, and the mass ratio of antioxidant 1010 to antioxidant 168 is 1:

1.

3. The anti-dripping ETFE film for a greenhouse according to claim 1, characterized by: The anti-dew drop master batch in the intermediate layer and the inner layer is prepared by the following steps: adding ETFE resin, anti-dew drop filler, antioxidant 1010, antioxidant 168 and hindered amine light stabilizer into a mixer and mixing for 5 minutes, then adding the mixture into a twin-screw extruder for melt extrusion, and then filtering, underwater pelletizing, drying and sieving to obtain the anti-dew drop master batch.

4. The anti-dripping ETFE film for a greenhouse according to claim 3, characterized by: The rotating speed during mixing in the preparation method of the anti-dew drop master batch is 1000 r / min, the mixing temperature is room temperature, and the melt extrusion temperature is 285-287℃; The underwater pelletizing temperature in the preparation method of the anti-dew drop master batch is 70-73℃, and particles with a particle size of 2 mm are obtained; The drying temperature in the preparation method of the anti-dew drop master batch is 80-85℃, the drying time is 30 minutes, and the obtained particles are sieved through an 8-mesh sieve; The anti-dew drop master batch is composed of the following raw materials in parts by mass: 100 parts of ETFE resin, 10-12 parts of anti-dew drop filler, 0.18-0.2 parts of antioxidant 1010, 0.18-0.2 parts of antioxidant 168 and 0.25-0.27 parts of hindered amine light stabilizer, and the hindered amine light stabilizer is light stabilizer XT-8.

5. The anti-dripping ETFE film for a greenhouse according to claim 1, characterized by: The preparation method of the anti-dripping filler comprises the following steps: ① preparation of pretreated nano-sepiolite: the nano-sepiolite is subjected to dehydration treatment to obtain dried nano-sepiolite, the dried nano-sepiolite powder is added into hydrochloric acid with a mass concentration of 2.5% for magnetic stirring reaction, after the reaction is completed, the pretreated nano-sepiolite is prepared by filtration, deionized water washing and vacuum drying treatment; ② preparation of pretreated magnesium borate whisker: the magnesium borate whisker is vacuum dried at 80 ℃ for 2 h; ③ preparation of pretreated nano-zinc gallate: the nano-zinc gallate is vacuum dried at 80 ℃ for 4 h; ④ the dehydrated ethanol and deionized water are uniformly mixed in a volume ratio of 95:5, then the KH-560 silane coupling agent is uniformly mixed to make the mass concentration of the KH-560 silane coupling agent be 2%, finally, glacial acetic acid is added to adjust the pH value of the system to 4.5, and the pre-hydrolysis liquid is prepared by hydrolysis at room temperature for 10 min; ⑤ the pretreated nano-sepiolite, the pretreated magnesium borate whisker and the pretreated nano-zinc gallate are added into the pre-hydrolysis liquid for magnetic stirring at room temperature for 30 min, then the temperature is increased to 64 ℃ for reflux reaction for 2 h under nitrogen protection; ⑥ after the reflux reaction is completed, the temperature is naturally cooled to 40 ℃, the nitrogen is turned off, the reaction mixture is vacuum filtered, the filter cake is collected, the filter cake is eluted with dehydrated ethanol for 3 times, then vacuum drying and sieving are performed to obtain the anti-dripping filler.

6. The anti-dripping ETFE film for a greenhouse according to claim 5, characterized by: In the preparation method of the pretreated nano-sepiolite in step ①, the dehydration treatment temperature is 80 ℃, the dehydration treatment pressure is -0.09 MPa, and the dehydration treatment time is 4 h. In the preparation method of the pretreated nano-sepiolite in step ①, the mass ratio of the hydrochloric acid to the dried nano-sepiolite is 5:1, the magnetic stirring reaction time is 1.5 h, the vacuum drying temperature is 80 ℃, the vacuum drying time is 2 h, and the vacuum drying pressure is -0.09 MPa.

7. The anti-dripping ETFE film for a greenhouse according to claim 5, characterized by: In step ⑤, the mass ratio of the pretreated nano-sepiolite, the pretreated magnesium borate whisker and the pretreated nano-zinc gallate is 6:3:

2. In step ⑤, the mass ratio of the pretreated nano-sepiolite, the pretreated magnesium borate whisker and the pretreated nano-zinc gallate to the pre-hydrolysis liquid is 1:

5.

8. The anti-dripping ETFE film for a greenhouse according to claim 5, characterized by: In step ⑥, the vacuum drying temperature is 80 ℃, the vacuum drying time is 2 h, the vacuum drying pressure is -0.09 MPa, and the sieving is performed through a 200-mesh sieve.

9. A method of preparing the anti-dripping ETFE film for a greenhouse according to claim 1, characterized by: The preparation method comprises the following steps: (1) the outer layer raw material, the middle layer raw material and the inner layer raw material are respectively added into a high-speed mixer for mixing, and after uniform mixing, the outer layer mixture, the middle layer mixture and the inner layer mixture are obtained; (2) the outer layer mixture, the middle layer mixture and the inner layer mixture are respectively added into a three-layer co-extrusion film blowing machine for film blowing forming, and then cooling, traction and winding are performed to obtain the anti-dripping ETFE film for greenhouses.

10. The method of claim 9, wherein the method is characterized by: In step (1), the parameters for mixing the outer layer, the middle layer and the inner layer are the same, the mixing temperature is room temperature, the mixing speed is 1000 r / min, and the mixing time is 5 min. Step (2) the temperature of the feeding section of the three-layer co-extrusion film blowing machine is 253-255℃, the temperature of the compression section is 270-275℃, the temperature of the melting section is 285-288℃, the temperature of the homogenizing section is 280-283℃, and the temperature of the die head is 275-278℃; In step (2), the three-layer melt is extruded through a three-layer co-extrusion die head, the blowing ratio is controlled to be 1.8, and the drawing ratio is controlled to be 3.0; In step (2), the air ring temperature during cooling and shaping is controlled to be 23℃, and the drawing speed is 22 m / min.

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