Anti-fog humidity-sensitive response antibacterial polyester film and preparation method thereof

Abstract

According to the anti-fog humidity-sensitive response antibacterial polyester film and the preparation method thereof, the polyester film is endowed with an efficient and controllable antibacterial function under various humidity through combination of Ag and an Ag-loaded MOF material (Ag particles are anchored in pores of the MOF material), the polyester film is endowed with good and lasting anti-fog performance through hydrophilic modified PET, and the anti-fog humidity-sensitive response antibacterial polyester film has the advantages that the anti-fog humidity-sensitive response antibacterial polyester film can be applied to the field of anti-fog and humidity-sensitive response antibacterial polyester film; and the anti-fog grade is 1-2. According to the invention, the Ag-loaded MOF material with an ultrahigh specific surface area (silver in MOF cannot be agglomerated together due to obstruction of the MOF material) is used for improving the antibacterial effect of the material in a high-humidity environment, the antibacterial effect can be regulated and controlled by controlling the pore size of the MOF material, controllability is realized, and the balance of antibacterial strength and antibacterial sustainability is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyester films, and relates to an anti-fog and humidity-sensitive responsive antibacterial polyester film and a preparation method thereof. Background Art

[0002] Due to its excellent mechanical strength, chemical resistance and transparency, polyester films are widely used in fields such as food and fruit packaging, medical device packaging, etc. However, in specific environments, such as high humidity or low-temperature refrigeration conditions, traditional polyester films are prone to a phenomenon where the packaging transparency decreases, affecting the display effect of the contents. In addition, the increase in humidity will also promote the growth of bacteria such as Escherichia coli and Staphylococcus aureus, thus affecting food safety and medical protection performance. Therefore, how to endow polyester films with anti-fog and humidity-responsive antibacterial functions has become an important research direction for current packaging materials.

[0003] Currently, in order to improve the anti-fog performance of polyester films, common methods include hydrophilic coating technologies, such as coating polyethylene glycol (PEG) or surfactants. However, this method has problems such as poor durability and easy peeling, which limits its long-term use. The durability of the anti-fog function is insufficient. The existing surface coating method is vulnerable to friction or solvent erosion, resulting in a decrease in the anti-fog effect over time. Especially in applications such as food packaging, the stability of the coating is a key issue.

[0004] In addition, most of the antibacterial packaging films on the market achieve antibacterial functions by doping with nano silver (Ag), zinc oxide (ZnO) or quaternary ammonium salts. However, the antibacterial effects of these materials are easily affected by humidity changes. Some nano silver has problems such as uncontrollable release and aggregation inactivation, resulting in attenuation of the antibacterial effect. The antibacterial function is uncontrollable. Under low humidity conditions, Ag may have a good effect. However, when the humidity increases, the growth of bacteria accelerates, and the rate of silver ion release from Ag is uncontrollable, and the aggregation of silver may reduce its activity, resulting in incomplete antibacterial properties. Summary of the Invention

[0005] In order to solve the defects of poor anti-fog performance and incomplete antibacterial performance of existing polyester films, on the one hand, the present invention provides an anti-fog and humidity-sensitive responsive antibacterial polyester film. The polyester film of the present invention combines nano Ag with Ag-loaded MOF materials (anchoring Ag particles on MOF materials), endowing the polyester film with an efficient and controllable antibacterial function at various humidities. Under low humidity conditions, water vapor is not easily introduced into the MOF pores, so nano Ag plays a major antibacterial role. However, under high humidity conditions, water vapor enters the MOF pores and contacts the Ag inside the pores to release silver ions. Due to the ultra-high specific surface area of the MOF material, the amount of silver ion release increases, thus achieving a strong antibacterial effect under high humidity conditions. Good and durable anti-fog performance is imparted to the polyester film through hydrophilic modification of PET.

[0006] Another aspect of the present invention provides a method for preparing the above-mentioned anti-fog moisture-sensitive response antibacterial polyester film.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides an anti-fog moisture-sensitive response antibacterial polyester film. The polyester film has a double-layer structure, with the surface layer being a pure PET layer and the inner layer being a functional layer prepared by doping hydrophilic modified PET mixed with nano-silver and a MOF material loaded with Ag. Among them, the hydrophilic modified PET is glycidyl methacrylate modified PET.

[0009] As a preferred embodiment of the present invention, in the hydrophilic modified PET, glycidyl methacrylate accounts for 10% of the weight of PET.

[0010] As a preferred embodiment of the present invention, the MOF material loaded with Ag is obtained by anchoring Ag particles on the MOF material.

[0011] As a preferred embodiment of the present invention, the mass ratio of hydrophilic modified PET, the MOF material loaded with Ag, and nano-silver is 900:80:20.

[0012] The present invention also provides a method for preparing the above-mentioned anti-fog moisture-sensitive response antibacterial polyester film. The preparation method includes the following steps:

[0013] 1) Preparation of hydrophilic modified PET: Heat and stir PET prepolymer, solvent and catalyst to obtain oligomers; raise the temperature, add glycidyl methacrylate, react, remove low-molecular by-products, melt extrude, cool and pelletize to obtain hydrophilic modified PET particles;

[0014] 2) Preparation of the MOF material loaded with Ag: Prepare a precursor solution, perform a solvothermal reaction, wash and dry to obtain the MOF material; soak the MOF material in a silver nitrate solution for a period of time, add a reducing solution to react; after washing and drying, obtain the MOF material loaded with Ag;

[0015] 3) Preparation of the auxiliary extrusion material: Mix the hydrophilic modified PET obtained in step 1), the MOF material loaded with Ag obtained in step 2), and nano-silver evenly to obtain the auxiliary extrusion material;

[0016] 4) Co-extrusion: Add pure PET particles to the main extruder, add the auxiliary extrusion material obtained in step 3) to the auxiliary extruder, and obtain a thick sheet through co-extrusion;

[0017] 5) Stretching treatment: Preheat the thick sheet obtained in step 4), and perform synchronous biaxial stretching on the preheated thick sheet for qualitative determination to obtain an anti-fog, humidity-sensitive, and antibacterial polyester film, where the thickness of the surface layer is 20 - 50 μm, and the thickness of the bottom layer is 10 - 40 μm.

[0018] As a preferred embodiment of the present invention, in step 1), the catalyst is antimony trioxide, the solvent is ethylene glycol, and the oligomer is obtained by reacting at 230 - 250 °C for 1.5 - 2.5 h; after the temperature is raised to 260 - 270 °C, glycidyl methacrylate is added, and the reaction time is 2.5 - 3.5 h.

[0019] As a preferred embodiment of the present invention, in step 2), the temperature of the solvothermal reaction is 100 - 200 °C, and the reaction time is 12 - 36 h.

[0020] As a preferred embodiment of the present invention, in step 4), the screw speed of the main extruder is 70 - 100 r / min, and the temperature is 270 - 290 °C.

[0021] As a preferred embodiment of the present invention, in step 4), the screw speed of the auxiliary extruder is 60 - 95 r / min, the temperature is 260 - 280 °C, the electrostatic voltage loaded on the die of the extruder is 6 - 7 kV, the temperature of the cold roll is 20 °C, and the thickness of the thick sheet is 390 - 1200 μm.

[0022] As a preferred embodiment of the present invention, in step 5), the preheating temperature is 90 - 125 °C, and the preheating time is 40 - 100 s; the stretching temperature is 120 - 130 °C, and in the synchronous biaxial stretching, the stretching ratio of the X-axis to the Y-axis is 3 - 4:1; the qualitative temperature is 100 - 120 °C.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) By synthesizing Ag and the Ag-loaded MOF material (anchoring Ag particles on the MOF material), the present invention endows the polyester film with an efficient and controllable antibacterial function at various humidities, and endows the polyester film with good and lasting anti-fog performance through hydrophilic modification of PET.

[0025] 2) The present invention uses the Ag-loaded MOF material with an ultra-high specific surface area (the silver in the MOF will not agglomerate due to the barrier of the MOF material) to enhance its antibacterial effect in a high-humidity environment, and the antibacterial effect can be regulated by controlling the pore size of the MOF material, with controllability, achieving the balance between antibacterial strength and antibacterial sustainability.

[0026] 3) The anti-fog, humidity-sensitive, and antibacterial polyester film prepared by the present invention has an anti-fog grade of 1 - 2. Specific embodiments

[0027] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0028] The present invention provides an anti-fogging humidity-sensitive response antibacterial polyester film. The polyester film has a double-layer structure, with the surface layer being a pure PET layer and the inner layer being a functional layer prepared by doping hydrophilic modified PET mixed with nano silver and MOF materials loaded with Ag. Among them, the hydrophilic modified PET is glycidyl methacrylate modified PET. By combining Ag and MOF materials loaded with Ag (anchoring Ag particles on the MOF materials), the polyester film is given an efficient and controllable antibacterial function at various humidities. By means of hydrophilic modified PET, the polyester film is given good and lasting anti-fogging performance.

[0029] Ag(s)+H2O+O2====Ag + +OH -

[0030] When silver comes into contact with water and oxygen, the released silver ions have a bactericidal function. The reason for using Ag and MOF materials loaded with Ag together is as follows: under low humidity conditions, the main antibacterial substance is Ag. Due to the porous structure of the MOF materials loaded with Ag, the Ag in the pores is not easily exposed to water vapor, resulting in poor antibacterial effects. However, Ag alone cannot be used as the antibacterial substance because under high humidity environments, Escherichia coli and Staphylococcus aureus are more likely to grow. At this time, substances with stronger antibacterial effects are needed to play a role. Ag may have insufficient activity due to agglomeration. By using MOF materials loaded with Ag with a super-high specific surface area (the silver in the MOF will not agglomerate due to the barrier of the MOF material), the antibacterial effect in high humidity environments can be enhanced, and the antibacterial effect can be regulated by controlling the pore size of the MOF materials, with controllability, achieving a balance between antibacterial strength and antibacterial sustainability.

[0031] Therefore, Ag and MOF materials loaded with Ag are used simultaneously to endow the film with efficient and controllable antibacterial properties under various humidity conditions.

[0032] In the present invention, the PET-GMA hydrophilic modification method:

[0033] Materials: PET prepolymer (80 g), ethylene glycol (EG, in excess, 80 mL), antimony trioxide (Sb2O3, 0.3 wt%), glycidyl methacrylate (GMA, 10 wt%, 8 g).

[0034] Steps: 1. Transesterification reaction (the first step of polycondensation): In a reaction kettle at 230 - 250 °C, heat and stir PET prepolymer + ethylene glycol + Sb2O3 for 2 h to form oligomers.

[0035] 2. Add GMA for polycondensation: Raise the temperature to 260 - 270 °C, add GMA (10 wt%), and continue stirring for 3 h. Remove low - molecular - weight by - products under high vacuum (<50 Pa) to obtain hydrophilic modified PET - GMA.

[0036] 3. Cooling and pelletizing: After the reaction is completed, melt - extrude, cool and pelletize for standby.

[0037] The synthesis method of the Ag - loaded MOF material is as follows:

[0038] Materials:

[0039] MOF support: UiO - 66 - NH2 (or MIL - 101(Cr), 40 g) (decomposition temperature is 300 - 350 °C), silver nitrate (AgNO3, 1 M, 100 mL), reducing agent: NaBH4 (0.1 M, 100 mL), solvent: ethanol + water (1:1).

[0040] Steps: 1. MOF synthesis (solvothermal method, UiO - 66 - NH2):

[0041] Preparation method of UiO - 66 - NH2 (solvothermal method) Material preparation: Zirconium source: ZrCl4 (zirconium tetrachloride) 1 mmol (0.233 g), organic ligand: 2 - aminoterephthalic acid (NH2 - BDC) 1 mmol (0.181 g), solvent: N,N - dimethylformamide (DMF) 30 mL, regulator: glacial acetic acid 2 mL or hydrochloric acid (6 M, 1 mL), washing solvent: ethanol (EtOH).

[0042] Synthesis steps

[0043] 1. Preparation of precursor solution:

[0044] Add 30 mL of DMF to a beaker, dissolve ZrCl4, and ultrasonicate for 10 min to completely disperse it. Take another beaker, add NH2 - BDC to DMF, and stir for 10 min until completely dissolved. Mix the two solutions and slowly add glacial acetic acid (or 6 M hydrochloric acid), and stir evenly.

[0045] 2. Solvothermal reaction:

[0046] Transfer the mixed solution to a 100 - mL polytetrafluoroethylene reaction kettle and seal it. Place it in a constant - temperature oven at 120 °C for 24 h and let it react statically. After the reaction is completed, cool to room temperature and collect the pale - yellow precipitate.

[0047] 3. Washing and drying:

[0048] Wash three times with DMF (to remove unreacted precursors). Then wash three times with ethanol (EtOH) to remove residual DMF. Dry in vacuum at 60 °C for 12 h to obtain UiO-66-NH2 powder.

[0049] 4. Ag + Loading: The MOF is soaked in AgNO3 solution for 12 h, and Ag + enters the MOF pores.

[0050] 5. Ag reduction: Add NaBH4 solution and stir for 2 h to reduce Ag + to form nano-Ag.

[0051] 6. Washing and drying: Wash with ethanol + water and dry in vacuum to obtain the Ag-loaded MOF material powder.

[0052] What changes the pore size of the MOF is the size of the Ag particles, and the size of the Ag particles affects the antibacterial strength. In the solvothermal reaction, the reaction conditions are 100 - 200 °C and 12 h - 36 h. Of course, there are many other means to change the pore size. In this invention, only two parameters, namely the reaction temperature and reaction time of the solvothermal reaction, are given.

[0053] Mixing of materials in the auxiliary extruder

[0054] PET-GMA (hydrophilic modified PET, matrix, 900 g), Ag-loaded MOF material (antibacterial + high humidity enhanced antibacterial + humidity reduction, 80 g), Ag nanoparticles (initial antibacterial, 20 g).

[0055] First, dry the Ag-loaded MOF material and Ag nanoparticles in vacuum at 60 °C for 2 h. Then put 900 g of PET-GMA, 80 g of the Ag-loaded MOF material and 20 g of Ag nanoparticles into a bag and mix evenly to obtain the materials for the auxiliary extruder.

[0056] Example 1

[0057] This example provides the preparation of an anti-fog, humidity-sensitive and antibacterial polyester film, including:

[0058] (1) Pour the main extruder material (the material for the main extruder is pure PET bright slice) into the main extruder, set the screw speed to 70 - 100 r / min and the temperature to 270 - 290 °C. Pour the above-mentioned materials for the auxiliary extruder into the auxiliary extruder, set the screw speed to 60 - 95 r / min and the temperature to 260 - 280 °C. Apply an electrostatic voltage of 6 - 7 kV at the die of the extruder, and the temperature of the cold roll is 20 °C to obtain a thick sheet with a thickness of 390 - 1200 μm.

[0059] (2) Perform stretching treatment on the thick sheet, including: preheating the thick sheet at a preheating temperature of 90 - 125 °C for 40 - 100 seconds, performing synchronous biaxial stretching on the preheated thick sheet at a stretching temperature of 120 - 130 °C, with the stretching ratio of the X-axis to the Y-axis being (3 - 4):1, and setting the shape at a setting temperature of 100 - 120 °C to obtain a film with a thickness of 30 - 90 μm, where the thickness of the surface layer (pure PET layer) is 20 - 50 μm and the thickness of the inner layer (functional layer) is 10 - 40 μm.

[0060] Comparative Example 1: The polyester film is a pure PET film.

[0061] Comparative Example 2: The polyester film is double-layered, with the surface layer being a pure PET layer and the bottom layer being a functional layer made of hydrophilic modified PET.

[0062] Comparative Example 3: The polyester film is double-layered, with the surface layer being a pure PET layer and the bottom layer being a functional layer made of a mixture of hydrophilic modified PET and MOF material loaded with Ag.

[0063] Comparative Example 4: The polyester film is double-layered, with the surface layer being a pure PET layer and the bottom layer being a functional layer made of a mixture of hydrophilic modified PET and nano-silver.

[0064] Testing of antibacterial properties

[0065] The antibacterial activity of the film against Escherichia coli and Staphylococcus aureus was determined by the bacterial counting method. After diluting the bacterial solution (105 CFU) with a liquid culture medium (PBS buffer solution), 0.1 g of blank filter paper and 0.1 g of the film sample were added respectively, and shaken and cultured for 24 h. After culturing, the bacterial solution was diluted 100 times with phosphate buffer solution. Then, 100 μL of the above-diluted bacterial solution was evenly coated on a Luria Bertani (LB) agar plate and cultured in an incubator at 37 °C.

[0066] The film samples were the polyester films prepared in Example 1 and the polyester films obtained in Comparative Examples 1 - 4.

[0067] Reduction of bacteria(%)=(a - b) / a×100%

[0068] a and b are the number of colonies formed on the agar plate after dilution of the bacterial solution co-cultured with the blank filter paper and the film sample respectively. See Tables 1 - 3 for the test of antibacterial sustainability.

[0069] Table 1. Results of culturing in an incubator at 37 °C for 24 h (60%RH)

[0070] Example 1 Comparative Example 4 Comparative Example 3 Comparative Example 2 Comparative Example 1 Inhibitory rate against Escherichia coli (%) 80 76 82 0 0 Inhibitory rate against Staphylococcus aureus (%) 78 75 81 0 0

[0071] Table 2. Results of culturing for 36 h (60% RH) in a 37°C incubator

[0072] Example 1 Comparative Example 4 Comparative Example 3 Comparative Example 2 Comparative Example 1 Inhibitory rate against Escherichia coli (%) 82 77 86 0 0 Inhibitory rate against Staphylococcus aureus (%) 79 77 83 0 0

[0073] Table 3. Results of culturing for 48 h (60% RH) in a 37°C incubator

[0074] Example 1 Comparative Example 4 Comparative Example 3 Comparative Example 2 Comparative Example 1 Inhibitory rate against Escherichia coli (%) 84 78 88 0 0 Inhibitory rate against Staphylococcus aureus (%) 80 78 84 0 0

[0075] For the comparison of antibacterial effects under different humidity conditions, see Tables 4 - 6.

[0076] Table 4. Results of culturing for 24 h (30% RH) in a 37°C incubator

[0077] Example 1 Comparative Example 4 Comparative Example 3 Comparative Example 2 Comparative Example 1 Inhibitory rate against Escherichia coli (%) 64 75 60 0 0 Inhibitory rate against Staphylococcus aureus (%) 62 73 59 0 0

[0078] Table 5. Results of culturing for 24 h (60% RH) in a 37°C incubator

[0079] Example 1 Comparative Example 4 Comparative Example 3 Comparative Example 2 Comparative Example 1 Inhibitory rate against Escherichia coli (%) 80 76 82 0 0 Inhibitory rate against Staphylococcus aureus (%) 78 75 81 0 0

[0080] Table 6. Results of culturing for 24 h (90% RH) in a 37°C incubator

[0081] Example 1 Comparative Example 4 Comparative Example 3 Comparative Example 2 Comparative Example 1 Inhibitory rate against Escherichia coli (%) 92 86 97 0 0 Inhibitory rate against Staphylococcus aureus (%) 91 81 95 0 0

[0082] Anti-fog performance test (direct visual observation method, GB / T 31726 - 2015): Classification of anti-fog performance levels:

[0083] 1. Classification of haze levels

[0084] The anti-fog performance is classified into the following levels according to the degree of water mist on the film surface:

[0085] 1. Level 1 (excellent): No atomization phenomenon, the surface is clear and transparent. Even under high humidity conditions, there is no obvious accumulation of fog droplets or water beads.

[0086] 2. Level 2 (good): Slight atomization, but the fog is relatively uniform, and the transparency of the film surface is basically maintained. There are only a small number of tiny fog droplets in some areas or on the film surface, but it does not affect the use effect.

[0087] 3. Level 3 (average): Moderate atomization, with obvious fog droplets or water beads accumulating on the surface, but the contents can still be recognized on the surface. The transparency has decreased, but it is not completely impossible to see the object.

[0088] 4. Level 4 (poor): Strong atomization, with a large area of water droplets accumulating on the surface, significantly affecting transparency, resulting in an inability to clearly see the surface or internal objects.

[0089] The film prepared in Example 1 was placed in the test environment for one day, and its anti-fog level was Grade 1. After one week, the anti-fog level was Grade 2.

[0090] As described above, the above are only the preferred embodiments of the present invention, and do not impose any formal or substantial limitations on the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the premise of the method of the present invention, several improvements and supplements can still be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. For those skilled in the art, without departing from the spirit and scope of the present invention, any equivalent changes made by using the technical content disclosed above, such as slight modifications, decorations, and evolutions, are equivalent embodiments of the present invention; at the same time, any equivalent changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An anti-fog moisture-sensitive responsive antibacterial polyester film, characterized in that: The polyester film is a double-layer structure, the surface layer is a pure PET layer, and the inner layer is a functional layer made of a MOF material doped with hydrophilic modified PET mixed with nanosilver and loaded with Ag; wherein the hydrophilic modified PET is glycidyl methacrylate modified PET.

2. The anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 1, characterized in that: In the hydrophilic modified PET, glycidyl methacrylate accounts for 10% of the weight of PET.

3. The anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 1, characterized in that: The Ag-loaded MOF material is a material in which Ag particles are anchored on the pores of the MOF material.

4. The anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 1, characterized in that: The mass ratio of hydrophilic modified PET, Ag-loaded MOF material and nanosilver is 900:80:

20.

5. A method for preparing the anti-fog moisture-sensitive responsive antibacterial polyester film according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: 1) Preparation of hydrophilic modified PET: PET prepolymer, solvent and catalyst are heated and stirred to obtain oligomers; the temperature is increased, glycidyl methacrylate is added, reacted, low molecular weight by-products are removed, melt extruded, cooled and pelletized to obtain hydrophilic modified PET particles; 2) Preparation of Ag-loaded MOF material: preparing a precursor solution, performing a solvent thermal reaction, washing, and drying to obtain a MOF material; soaking the MOF material in a silver nitrate solution for a period of time, adding a reducing solution to react; washing and drying to obtain an Ag-loaded MOF material; 3) Preparation of auxiliary extrusion material: the hydrophilic modified PET obtained in step 1), the Ag-loaded MOF material obtained in step 2) and nanosilver are uniformly mixed to obtain auxiliary extrusion material; 4) Co-extrusion: adding pure PET particles into the main extruder, adding the auxiliary extrudate obtained in step 3) into the auxiliary extruder, and obtaining a thick sheet by co-extrusion; 5) Stretching treatment: preheat the thick sheet obtained in step 4), perform synchronous biaxial stretching on the preheated thick sheet, and characterize it to obtain an anti-fog moisture-sensitive responsive antibacterial polyester film, wherein the thickness of the surface layer is 20-50 μm and the thickness of the bottom layer is 10-40 μm.

6. The method for preparing an anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 5, characterized in that: In step 1), the catalyst is antimony trioxide, the solvent is ethylene glycol, and the reaction is carried out at 230-250° C. for 1.5-2.5 hours to obtain an oligomer; after the temperature is increased to 260-270° C., glycidyl methacrylate is added, and the reaction time is 2.5-3.5 hours.

7. The method for preparing an anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 5, characterized in that: In step 2), the temperature of the solvent thermal reaction is 100-200° C., and the reaction time is 12-36 hours.

8. The method for preparing an anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 5, characterized in that: In step 4), the screw speed of the main extruder is 70-100 r / min and the temperature is 270-290°C.

9. The method for preparing an anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 5, characterized in that: In step 4), the screw speed of the auxiliary extruder is 60-95r / min, the temperature is 260-280°C, the electrostatic voltage loaded on the extruder die is 6-7kV, the temperature of the cold roller is 20°C, and the thickness of the thick sheet is 390-1200μm.

10. The method for preparing an anti-fog moisture-sensitive responsive antibacterial polyester film according to claim 5, characterized in that: In step 5), the preheating temperature is 90-125°C, the preheating time is 40-100s; the stretching temperature is 120-130°C, and in the synchronous biaxial stretching, the X-axis to Y-axis stretching ratio is 3-4:1; the setting temperature is 100-120°C.