High-barrier polycrystalline silicon packaging film and preparation method thereof

Abstract

The invention discloses a high-barrier polycrystalline silicon packaging film and a preparation method thereof, and relates to the technical field of packaging materials. The invention discloses a high-barrier polycrystalline silicon packaging film. The composite material is prepared from the following raw materials in parts by weight: 15 to 25 parts of ethylene-vinyl alcohol copolymer, 10 to 18 parts of polyvinylidene chloride, 5 to 10 parts of nano montmorillonite, 8 to 15 parts of modified polylactic acid, 3 to 6 parts of tributyl citrate, 1 to 3 parts of antioxidant 1010, 1 to 3 parts of ultraviolet light absorber UV-531, 0.5 to 1.5 parts of nucleating agent NA-11, 1 to 2 parts of silane coupling agent KH-550 and 3 to 7 parts of modified silicon dioxide aerogel. 2 to 5 parts of vinyl trimethoxy silane, 1 to 3 parts of nano silver and 20 to 30 parts of deionized water. The high-barrier polycrystalline silicon packaging film provided by the invention has remarkable advantages and scientific raw material ratio, is prepared by a special process, has excellent barrier performance, and can effectively block oxygen, water vapor and the like. The polycrystalline silicon packaging film is good in mechanical performance, not prone to damage, antibacterial, antioxidant and anti-ultraviolet, the quality guarantee period of polycrystalline silicon can be prolonged, the product quality can be guaranteed, and the polycrystalline silicon packaging film has great application value in the field of polycrystalline silicon packaging.

Description

Technical Field

[0001] The invention relates to the technical field of packaging materials, in particular to a high-barrier polysilicon packaging film and a preparation method thereof. Background Art

[0002] Driven by the accelerated transformation of the global energy structure and the rapid development of the electronics industry, the market demand for polysilicon, as the core basic material of the electronics and photovoltaic industries, has shown explosive growth, and the scale of the industry has continued to expand. The purity of polysilicon plays a decisive role in the performance of electronic products and the conversion efficiency of photovoltaic cells, so there are almost stringent requirements for its storage and transportation environment.

[0003] At present, the packaging of polysilicon mainly relies on traditional packaging films, but these packaging films have a series of problems that are difficult to ignore. In terms of barrier properties, traditional packaging films cannot effectively resist the penetration of oxygen and water vapor. When polysilicon is stored, oxygen will slowly react with silicon to form an oxide layer, changing its electrical properties; during transportation, the intrusion of water vapor will cause hydrolysis of the silicon surface, affecting its purity and stability, thereby reducing the quality of polysilicon in subsequent production applications and increasing production costs.

[0004] In terms of mechanical properties, traditional packaging films lack strength and flexibility. Frequent operations during packaging may cause tiny cracks in the packaging film; during handling and transportation, external forces such as vibration and friction can easily cause the packaging film to break. Once the packaging film is broken, the polysilicon is directly exposed, which will not only be contaminated by dust and impurities, but may also be damaged by collisions, seriously affecting product quality and corporate economic benefits.

[0005] In terms of antibacterial properties, ordinary packaging films do not have antibacterial properties. The polysilicon production environment is not absolutely sterile. During storage and transportation, microorganisms are prone to grow in the packaging film. Microbial metabolites can corrode polysilicon, or the microorganisms themselves attach to the silicon surface, affecting its performance and posing a potential threat to the quality of polysilicon.

[0006] With the awakening of environmental awareness in the whole society and the increasingly stringent environmental regulations, the environmental friendliness of packaging materials has become an important consideration. Traditional packaging films are mostly non-degradable materials, which are discarded after a large amount of use, causing long-term pressure on the ecological environment.

[0007] In summary, it is urgent to develop polysilicon packaging films that combine high barrier properties, good mechanical properties, antibacterial properties and environmental protection. This is not only the key to ensuring the quality of polysilicon products, but also an inevitable choice to promote the green and sustainable development of the polysilicon industry. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a high-barrier polysilicon packaging film and a preparation method thereof, which solve the above-mentioned problems.

[0009] To achieve the above objectives, the present invention is implemented through the following technical solutions: A high-barrier polysilicon packaging film comprises the following raw materials in parts by weight: 15-25 parts of ethylene-vinyl alcohol copolymer, 10-18 parts of polyvinylidene chloride, 5-10 parts of nano-montmorillonite, 8-15 parts of modified polylactic acid, 3-6 parts of tributyl citrate, 1-3 parts of antioxidant 1010, 1-3 parts of ultraviolet absorber UV-531, 0.5-1.5 parts of nucleating agent NA-11, 1-2 parts of silane coupling agent KH-550, 3-7 parts of modified silica aerogel, 2-5 parts of vinyltrimethoxysilane, 1-3 parts of nano-silver and 20-30 parts of deionized water.

[0010] Furthermore, the modified polylactic acid is specifically prepared in the following steps: A1. Add polylactic acid, maleic anhydride and p-toluenesulfonic acid into a three-necked flask, then add chloroform, introduce nitrogen, and stir at 65°C for 4 hours. After the reaction, pour the reaction solution into methanol for precipitation, filter with a Buchner funnel, wash, and dry to obtain maleic anhydride grafted polylactic acid. A2, maleic anhydride grafted polylactic acid, amino carbon nanotubes, and dibutyltin dilaurate were added to a three-necked flask, and N,N-dimethylformamide was added, nitrogen was introduced, and stirred at 85°C for 4 hours; after the reaction was completed, the reaction solution was dialyzed and freeze-dried to obtain carbon nanotube-modified polylactic acid; A3. Add carbon nanotube-modified polylactic acid, poly(butylene adipate-terephthalate) and diisopropylbenzene peroxide into a three-necked flask, then add xylene, introduce nitrogen, and stir the reaction at 125°C for 3 hours. After the reaction is completed, stop heating, let the reaction solution cool naturally to room temperature, filter with a Buchner funnel, transfer the filtered liquid to a rotary evaporator for rotary evaporation, and then put the product into a vacuum drying oven for drying to obtain the final modified polylactic acid.

[0011] Furthermore, in the step A1, the dosage ratio of polylactic acid, maleic anhydride, p-toluenesulfonic acid and chloroform is 12g:6g:0.8g:120mL; the number average molecular weight of polylactic acid is 80,000; the flow rate of nitrogen is 200mL / min, and the introduction time is 15min; the stirring speed is 400r / min; methanol is precooled to 0°C; the precipitate is washed with methanol until the pH value of the washing liquid is 7; the product is dried at 45°C and a vacuum degree of 0.08MPa for 10h.

[0012] Furthermore, in the A2 step, the dosage ratio of maleic anhydride grafted polylactic acid, amino carbon nanotubes, dibutyltin dilaurate, and N,N-dimethylformamide is 11g:4g:1.5g:110mL; the molecular weight of the amino carbon nanotubes is 50,000; the flow rate of nitrogen is 150mL / min, and the introduction time is 20min; the stirring speed is 500r / min; a dialysis bag with a molecular weight cutoff of 2000Da is selected, and the product is dialyzed in deionized water for 4 days, during which the deionized water is replaced 3 times a day; after dialysis, the sample is pre-frozen to -45°C and maintained for 3h, and then sublimated and dried for 30h under a vacuum degree of 15Pa.

[0013] Furthermore, in the step A3, the amount ratio of carbon nanotube-modified polylactic acid, polybutylene adipate-terephthalate, diisopropylbenzene peroxide and xylene is 12g:6g:0.8g:120mL; the flow rate of nitrogen is 180mL / min, and the introduction time is 15min; the stirring speed is 550r / min; the rotary evaporation temperature is 60°C and the vacuum degree is 0.06MPa; the product is dried at 75°C and the vacuum degree is 0.09MPa for 15h.

[0014] Maleic anhydride reacts with the hydroxyl group of polylactic acid under the catalysis of p-toluenesulfonic acid to generate maleic anhydride grafted polylactic acid, introduces reactive double bonds, and increases the reactive sites. The amino groups of the aminated carbon nanotubes react with the double bonds of the maleic anhydride grafted polylactic acid to achieve uniform dispersion of the carbon nanotubes in the polylactic acid and enhance the mechanical properties. Diisopropylbenzene peroxide initiates a cross-linking reaction between polybutylene adipate-terephthalate and carbon nanotube-modified polylactic acid to form a three-dimensional network structure, improving flexibility and processing properties.

[0015] Furthermore, the modified silica aerogel is specifically prepared in the following steps: B1. Add silica aerogel to anhydrous ethanol, ultrasonically disperse the mixture for 35 minutes, add 3-aminopropyltrimethoxysilane to the suspension, place the reaction container in a constant temperature water bath, heat to 55° C., and stir to react for 3.5 hours; after the reaction is completed, use a sand core funnel to filter under reduced pressure, collect the solid product, wash and dry it to obtain amino silica aerogel; B2, adding the aminated silica aerogel to toluene, transferring the mixture to a three-necked flask, stirring and dispersing, adding glycidyl trimethylammonium chloride, heating the reaction system to 85°C and stirring for 4.5h; after the reaction is completed, stopping heating, cooling the reaction solution to room temperature, using a sand core funnel to perform vacuum filtration, collecting the solid product, washing, and drying to obtain quaternary ammonium salt modified silica aerogel; B3. Add the quaternary ammonium salt modified silica aerogel into anhydrous ethanol and ultrasonically disperse it for 35 minutes, add nanosilver sol into the suspension, continue ultrasonically dispersing it for 10 minutes, and then place the reaction container on a magnetic stirrer and stir the reaction at room temperature for 2.5 hours; after the reaction is completed, centrifuge and separate, collect the precipitated product, wash it, and dry it to obtain the final modified silica aerogel.

[0016] Furthermore, in step B1, the amount ratio of silica aerogel, anhydrous ethanol and 3-aminopropyltrimethoxysilane is 12 g: 130 mL: 4 g; the specific surface area is 600 m 2 / g, an average pore size of 15nm silica aerogel; the stirring speed is 300r / min; the product is dried at 60°C and a vacuum degree of 0.08MPa for 12h; in the step B2, the amount ratio of the amino silica aerogel, toluene, and glycidyltrimethylammonium chloride is 11g:110mL:6g; the stirring speed is 350r / min; the washed solid product is dried at 70°C and a vacuum degree of 0.09MPa for 15h.

[0017] Furthermore, in the step B3, the dosage ratio of quaternary ammonium salt modified silica aerogel, anhydrous ethanol and nano silver sol is 12g:130mL:4g; the stirring speed is 400r / min; the centrifugal separation speed is 5000r / min, and each centrifugation is 15min; the washed precipitated product is dried at 50°C and a vacuum degree of 0.07MPa for 24h.

[0018] The methoxy group of 3-aminopropyltrimethoxysilane is hydrolyzed to generate silanol, which condenses with the hydroxyl groups on the surface of silica aerogel to introduce amino groups and enhance its compatibility with other raw materials. The epoxy group of glycidyltrimethylammonium chloride undergoes a ring-opening reaction with the amino group of amination silica aerogel to introduce quaternary ammonium salt groups and impart antibacterial properties. Nanosilver sol combines with quaternary ammonium salt-modified silica aerogel through electrostatic action and physical adsorption to further enhance the antibacterial properties. Nanosilver can also fill pores and improve the barrier properties of packaging films.

[0019] A method for preparing a high-barrier polysilicon packaging film specifically comprises the following steps: S1. Add nano-montmorillonite and modified silica aerogel into a high-speed mixer and stir for 5 minutes. Then, add modified polylactic acid, ethylene-vinyl alcohol copolymer and polyvinylidene chloride in sequence and stir at an accelerated speed for 8 minutes. Then, add tributyl citrate, antioxidant 1010, UV absorber UV-531, nucleating agent NA-11, silane coupling agent KH550, vinyl trimethoxy silane and nano silver antibacterial agent and continue stirring for 7 minutes. Finally, add deionized water and stir at an accelerated speed for 15 minutes. S2, placing the polyester film in a plasma treatment device, treating it with oxygen plasma for 5 minutes, and immediately feeding the treated polyester film into the feeding area of ​​a casting machine, setting the temperature of the screw extruder to 150°C, setting the traction speed to 0.7 m / min, and casting the mixed slurry on the polyester film carrier through the casting machine, the casting speed is 0.7 m / min, and the casting thickness is 0.3 mm; S3. Send the wet polyester film after cast molding into a pre-drying box, and heat it with hot air circulation. The temperature is set to 50℃ and the drying time is 40min. The pre-dried film enters the main drying area, and the main drying area adopts segmented heating. The temperature of the first section is set to 60℃ and the drying time is 50min. The temperature of the second section is increased to 70℃ and the drying time is 40min. After the main drying is completed, send the film into a curing box for curing treatment. The temperature of the curing box is set to 110℃ and the curing time is 2h. After the curing is completed, the packaging film is slowly cooled to room temperature by a combination of air cooling and water cooling.

[0020] Furthermore, in the step S1, the initial stirring speed is 500 r / min, the speed after acceleration is 600 r / min, and the speed after further acceleration is 800 r / min.

[0021] The present invention provides a high-barrier polysilicon packaging film and a preparation method thereof, which have the following beneficial effects: 1. Ethylene-vinyl alcohol copolymers rely on the flexibility of the ethylene units in the molecular structure and the hydrogen bonding between the hydroxyl groups of the vinyl alcohol units and oxygen and water vapor to naturally block the penetration of small molecules; polyvinylidene chloride can significantly reduce the permeability of gases and liquids due to its strong intermolecular forces and compact structure. The lamellar structure of nano-montmorillonite makes the permeation path of oxygen and water vapor tortuous, reducing the permeability coefficient. Vinyl trimethoxysilane cross-links to form a three-dimensional network, making the packaging film structure denser and enhancing the barrier effect. They work together to build an efficient barrier to prevent polysilicon from oxidation and moisture, and maintain stable quality.

[0022] 2. In terms of mechanical performance improvement, the three-step modified polylactic acid allows the packaging film to perform well in practical applications. The first step of modification creates conditions for subsequent reactions, and the amino carbon nanotubes added in the second step are like building countless microscopic "support skeletons" inside the packaging film, greatly enhancing the overall structural strength of the packaging film. During packaging and transportation, when faced with external forces such as extrusion and stretching, the packaging film can effectively disperse stress and is not prone to cracking and tearing, ensuring the integrity of polysilicon. The third step is the addition of polybutylene adipate-terephthalate, which gives the packaging film good flexibility. When the packaging film is subjected to shocks such as vibration and collision, it can buffer external forces by deforming itself to avoid damage due to excessive brittleness, thereby reducing the risk of polysilicon being contaminated or damaged due to the rupture of the packaging film. Coupling agent KH-550 plays a key connecting role in the packaging film. It tightly combines inorganic fillers such as nano-montmorillonite with the polymer matrix, making the internal structure of the packaging film more stable. During the packaging, handling and transportation of polysilicon, even if it is subjected to relatively severe external forces such as friction and collision, the packaging film can remain intact due to its enhanced structural stability, and continue to provide reliable physical protection for the polysilicon, effectively reducing the probability of product damage and ensuring the quality of polysilicon.

[0023] 3. The quaternary ammonium salt groups in the modified silica aerogel destroy the microbial cell membrane, and the nanosilver inhibits the growth and reproduction of microorganisms. The two work together to fight bacteria. Antioxidant 1010 captures free radicals, interrupts the oxidation reaction, and protects the molecular chain of the packaging film. The ultraviolet absorber UV-531 absorbs ultraviolet rays and converts energy to prevent the packaging film from being damaged by ultraviolet rays, ensuring the protection of polysilicon in different environments.

[0024] 4. The present invention not only ensures the high performance of the packaging film, but also pays attention to environmental protection. The modified polylactic acid is prepared from renewable resources and is biodegradable, and this property is retained after modification. Additives such as tributyl citrate are also biodegradable, and work together with the modified polylactic acid to ensure performance. After being discarded, they decompose together to reduce environmental pressure. This method of preparing packaging film with degradable raw materials is in line with the trend of environmental protection and promotes the green development of the polysilicon industry. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1: Preparation of high barrier polysilicon packaging film, the specific preparation steps are as follows: S1. Add 5 parts of nano-montmorillonite and 3 parts of modified silica aerogel into a high-speed mixer and stir at 500 r / min for 5 min. Then, add 8 parts of modified polylactic acid, 15 parts of ethylene-vinyl alcohol copolymer and 10 parts of polyvinylidene chloride in turn and stir at 600 r / min for 8 min. Then, add 3 parts of tributyl citrate, 1 part of antioxidant 1010, 1 part of ultraviolet absorber UV-531, 0.5 parts of nucleating agent NA-11, 1 part of silane coupling agent KH550, 2 parts of vinyl trimethoxy silane and 1 part of nano silver antibacterial agent, and continue stirring for 7 min. Finally, add 20 parts of deionized water and stir at 800 r / min for 15 min. S2, placing the polyester film in a plasma treatment device, treating it with oxygen plasma for 5 minutes, and immediately feeding the treated polyester film into the feeding area of ​​a casting machine, setting the temperature of the screw extruder to 150°C, setting the traction speed to 0.7 m / min, and casting the mixed slurry on the polyester film carrier through the casting machine, the casting speed is 0.7 m / min, and the casting thickness is 0.3 mm; S3. Send the wet polyester film after cast molding into a pre-drying box, and heat it with hot air circulation. The temperature is set to 50℃ and the drying time is 40min. The pre-dried film enters the main drying area, and the main drying area adopts segmented heating. The temperature of the first section is set to 60℃ and the drying time is 50min. The temperature of the second section is increased to 70℃ and the drying time is 40min. After the main drying is completed, send the film into a curing box for curing treatment. The temperature of the curing box is set to 110℃ and the curing time is 2h. After the curing is completed, the packaging film is slowly cooled to room temperature by a combination of air cooling and water cooling.

[0027] Example 2, preparing a high barrier polysilicon packaging film, the specific preparation steps are as follows: S1. Add 10 parts of nano-montmorillonite and 7 parts of modified silica aerogel into a high-speed mixer and stir at 500 r / min for 5 min. Then, add 15 parts of modified polylactic acid, 25 parts of ethylene-vinyl alcohol copolymer and 18 parts of polyvinylidene chloride in turn and stir at 600 r / min for 8 min. Then, add 6 parts of tributyl citrate, 3 parts of antioxidant 1010, 3 parts of ultraviolet absorber UV-531, 1.5 parts of nucleating agent NA-11, 2 parts of silane coupling agent KH550, 5 parts of vinyl trimethoxy silane and 3 parts of nano silver antibacterial agent, and continue stirring for 7 min. Finally, add 30 parts of deionized water and stir at 800 r / min for 15 min. S2, placing the polyester film in a plasma treatment device, treating it with oxygen plasma for 5 minutes, and immediately feeding the treated polyester film into the feeding area of ​​a casting machine, setting the temperature of the screw extruder to 150°C, setting the traction speed to 0.7 m / min, and casting the mixed slurry on the polyester film carrier through the casting machine, the casting speed is 0.7 m / min, and the casting thickness is 0.3 mm; S3. Send the wet polyester film after cast molding into a pre-drying box, and heat it with hot air circulation. The temperature is set to 50℃ and the drying time is 40min. The pre-dried film enters the main drying area, and the main drying area adopts segmented heating. The temperature of the first section is set to 60℃ and the drying time is 50min. The temperature of the second section is increased to 70℃ and the drying time is 40min. After the main drying is completed, send the film into a curing box for curing treatment. The temperature of the curing box is set to 110℃ and the curing time is 2h. After the curing is completed, the packaging film is slowly cooled to room temperature by a combination of air cooling and water cooling.

[0028] Example 3, preparing a high barrier polysilicon packaging film, the specific preparation steps are as follows: S1. Add 7 parts of nano-montmorillonite and 5 parts of modified silica aerogel into a high-speed mixer and stir at 500 r / min for 5 min. Then, add 11 parts of modified polylactic acid, 20 parts of ethylene-vinyl alcohol copolymer and 14 parts of polyvinylidene chloride in turn and stir at 600 r / min for 8 min. Then, add 4 parts of tributyl citrate, 2 parts of antioxidant 1010, 2 parts of ultraviolet absorber UV-531, 1 part of nucleating agent NA-11, 1 part of silane coupling agent KH550, 3 parts of vinyl trimethoxy silane and 2 parts of nano silver antibacterial agent and continue stirring for 7 min. Finally, add 25 parts of deionized water and stir at 800 r / min for 15 min. S2, placing the polyester film in a plasma treatment device, treating it with oxygen plasma for 5 minutes, and immediately feeding the treated polyester film into the feeding area of ​​a casting machine, setting the temperature of the screw extruder to 150°C, setting the traction speed to 0.7 m / min, and casting the mixed slurry on the polyester film carrier through the casting machine, the casting speed is 0.7 m / min, and the casting thickness is 0.3 mm; S3. Send the wet polyester film after cast molding into a pre-drying box, and heat it with hot air circulation. The temperature is set to 50℃ and the drying time is 40min. The pre-dried film enters the main drying area, and the main drying area adopts segmented heating. The temperature of the first section is set to 60℃ and the drying time is 50min. The temperature of the second section is increased to 70℃ and the drying time is 40min. After the main drying is completed, send the film into a curing box for curing treatment. The temperature of the curing box is set to 110℃ and the curing time is 2h. After the curing is completed, the packaging film is slowly cooled to room temperature by a combination of air cooling and water cooling.

[0029] Example 4, preparation of modified polylactic acid, the specific preparation steps are as follows: A1. Add 12g of polylactic acid with a number average molecular weight of 80,000, 6g of maleic anhydride, and 0.8g of p-toluenesulfonic acid into a three-necked flask, then add 120mL of chloroform, introduce nitrogen at a flow rate of 200mL / min for 15min, and stir at 400r / min for 4h at 65°C; after the reaction, pour the reaction solution into methanol precooled to 0°C for precipitation, filter with a Buchner funnel, wash the precipitate with methanol until the pH value of the washing solution is 7, and dry the product at 45°C and a vacuum degree of 0.08MPa for 10h to obtain maleic anhydride grafted polylactic acid; A2, 11g maleic anhydride grafted polylactic acid and 4g amino carbon nanotubes with a molecular weight of 50,000, 1.5g dibutyltin dilaurate were added to a three-necked flask, and then 110mL N, N-dimethylformamide was added, nitrogen was introduced, the flow rate of nitrogen was 150mL / min, the introduction time was 20min, and the reaction was stirred at 85°C and 500r / min for 4h; after the reaction, the reaction solution was dialyzed in a dialysis bag with a molecular weight cutoff of 2000Da, and the product was dialyzed in deionized water for 4 days, during which the deionized water was replaced 3 times a day; after dialysis, the sample was pre-frozen to -45°C and kept for 3h, and then sublimation dried for 30h under a vacuum degree of 15Pa to obtain carbon nanotube modified polylactic acid; A3. Add 12g of carbon nanotube-modified polylactic acid, 6g of poly(butylene adipate-terephthalate) and 0.8g of diisopropylbenzene peroxide into a three-necked flask, add 120mL of xylene, introduce nitrogen at a flow rate of 180mL / min for 15min, and stir at 125°C and 550r / min for 3h. After the reaction, stop heating, let the reaction solution cool naturally to room temperature, filter with a Buchner funnel, transfer the filtered liquid to a rotary evaporator, and rotary evaporate at 60°C and a vacuum degree of 0.06MPa. The product is then placed in a drying oven at 75°C and a vacuum degree of 0.09MPa for 15h to obtain the final modified polylactic acid.

[0030] Example 5, preparation of modified silica aerogel, the specific preparation steps are as follows: B1, 12g of specific surface area is 600m 2 / g of silica aerogel with an average pore size of 15nm was added to 130mL of anhydrous ethanol, the mixed solution was ultrasonically dispersed for 35min, 4g of 3-aminopropyltrimethoxysilane was added to the suspension, the reaction container was placed in a constant temperature water bath, the temperature was raised to 55°C, and the reaction was stirred at 300r / min for 3.5h; after the reaction, the sand core funnel was used for reduced pressure filtration, the solid product was collected, washed, and dried at 60°C and a vacuum degree of 0.08MPa for 12h to obtain amino silica aerogel; B2, 11g of amination silica aerogel was added to 110mL of toluene, the mixture was transferred to a three-necked flask, stirred and dispersed at 350r / min, and then 6g of glycidyl trimethylammonium chloride was added, and the reaction system was heated to 85°C and stirred for 4.5h; after the reaction was completed, the heating was stopped, and after the reaction solution was cooled to room temperature, a sand core funnel was used for reduced pressure filtration, the solid product was collected, and the washed solid product was dried at 70°C and a vacuum degree of 0.09MPa for 15h to obtain quaternary ammonium salt modified silica aerogel; B3. 10 g of quaternary ammonium salt-modified silica aerogel was added to 130 mL of anhydrous ethanol and ultrasonically dispersed for 35 min. 4 g of nano-silver sol was added to the suspension and ultrasonically dispersed for 10 min. The reaction vessel was then placed on a magnetic stirrer and stirred at 400 r / min for 2.5 h at room temperature. After the reaction was completed, the reaction was centrifuged at 5000 r / min for 15 min each time, the precipitated product was collected, and then washed. The washed precipitated product was dried at 50° C. and a vacuum degree of 0.07 MPa for 24 h to obtain the final modified silica aerogel.

[0031] Comparative Example 1: A high barrier polysilicon packaging film is prepared. The specific preparation steps are as follows: The remaining steps remain unchanged, only the modified polylactic acid in Example 2 is replaced by polylactic acid without any treatment to prepare a high barrier polycrystalline silicon packaging film.

[0032] Comparative Example 2: preparing a high barrier polysilicon packaging film, the specific steps are as follows: The remaining steps remained unchanged, except that the modified silica aerogel in Example 2 was replaced by silica aerogel without any treatment to prepare a high-barrier polycrystalline silicon packaging film.

[0033] Test items Test Method Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 <![CDATA[Oxygen transmission rate (cm 3 / (m 2 ·24h·0.1MPa))]]> According to GB / T1038-2000 standard, use the differential pressure gas permeameter test 8 6 7 20 18 <![CDATA[Water vapor transmission rate (g / (m 2 ·24 h))]]> According to GB / T1037-1988 standard, the cup method is used for testing 10 8 9 25 22 Tensile strength (MPa) According to GB / T1040.3-2006 standard, tensile test is carried out using a universal material testing machine 45 50 48 30 32 Elongation at break (%) Also according to GB / T1040.3-2006 standard, record in the tensile test 120 130 125 80 85 Antibacterial rate (%) According to GB / T21510-2008 standard, the antibacterial performance against Escherichia coli and Staphylococcus aureus was tested by film sticking method. Escherichia coli 98 Staphylococcus aureus 97 Escherichia coli 99 Staphylococcus aureus 98 Escherichia coli 98 Staphylococcus aureus 97 Escherichia coli 30 Staphylococcus aureus 25 Escherichia coli 40 Staphylococcus aureus 35 Antioxidant performance (induction period, min) The oxidation induction period of the packaging film was tested in an aerobic environment at a certain temperature by thermogravimetric analysis-differential scanning calorimetry (TG-DSC). 120 135 130 60 70 Ultraviolet Protection Factor (UPF) According to GB / T18830-2009 standard, use UV transmittance tester to measure 50+ 50+ 50+ 20 25 Degradation rate (%) The packaging film samples were buried in a specific soil environment, and samples were taken regularly. The degradation rate after 6 months was determined by gravimetric analysis. 30 35 32 5 8 Comparing the performance test results of Examples 1-3 with Comparative Examples 1-2, it can be seen that the high barrier polysilicon packaging film of the present invention has excellent performance. In terms of barrier performance, the oxygen and water vapor permeability of the examples is low, while that of the comparative examples is high; in terms of mechanical performance, the examples have high tensile strength and large elongation at break, while that of the comparative examples is low and more easily damaged; in terms of antibacterial properties, the antibacterial rate of the examples exceeds 97%, while that of the comparative examples is only 25-40%; in terms of antioxidant and UV resistance, the examples have long oxidation induction periods and high protection factors, while that of the comparative examples is poor and prone to aging; in terms of environmental performance, the degradation rate of the examples in 6 months is 30-35%, which is much higher than the 5-8% of the comparative examples.

[0034] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A high barrier polysilicon packaging film, characterized in that: The invention comprises the following raw materials in parts by weight: 15-25 parts of ethylene-vinyl alcohol copolymer, 10-18 parts of polyvinylidene chloride, 5-10 parts of nano-montmorillonite, 8-15 parts of modified polylactic acid, 3-6 parts of tributyl citrate, 1-3 parts of antioxidant 1010, 1-3 parts of ultraviolet absorber UV-531, 0.5-1.5 parts of nucleating agent NA-11, 1-2 parts of silane coupling agent KH-550, 3-7 parts of modified silica aerogel, 2-5 parts of vinyltrimethoxysilane, 1-3 parts of nano-silver and 20-30 parts of deionized water.

2. The high barrier polysilicon packaging film according to claim 1, characterized in that: The modified polylactic acid is specifically prepared in the following steps: A1. Add polylactic acid, maleic anhydride and p-toluenesulfonic acid into a three-necked flask, then add chloroform, introduce nitrogen, and stir at 65°C for 4 hours. After the reaction, pour the reaction solution into methanol for precipitation, filter with a Buchner funnel, wash, and dry to obtain maleic anhydride grafted polylactic acid. A2, maleic anhydride grafted polylactic acid, amino carbon nanotubes, and dibutyltin dilaurate were added to a three-necked flask, and N,N-dimethylformamide was added, nitrogen was introduced, and stirred at 85°C for 4 hours; after the reaction was completed, the reaction solution was dialyzed and freeze-dried to obtain carbon nanotube-modified polylactic acid; A3. Add carbon nanotube-modified polylactic acid, poly(butylene adipate-terephthalate) and diisopropylbenzene peroxide into a three-necked flask, then add xylene, introduce nitrogen, and stir the reaction at 125°C for 3 hours. After the reaction is completed, stop heating, let the reaction solution cool naturally to room temperature, filter with a Buchner funnel, transfer the filtered liquid to a rotary evaporator for rotary evaporation, and then put the product into a vacuum drying oven for drying to obtain the final modified polylactic acid.

3. The high barrier polysilicon packaging film according to claim 2, characterized in that: In the step A1, the dosage ratio of polylactic acid, maleic anhydride, p-toluenesulfonic acid and chloroform is 12g:6g:0.8g:120mL; the number average molecular weight of polylactic acid is 80,000; the flow rate of nitrogen is 200mL / min, and the introduction time is 15min; the stirring speed is 400r / min; methanol is precooled to 0°C; the precipitate is washed with methanol until the pH value of the washing liquid is 7; the product is dried at 45°C and a vacuum degree of 0.08MPa for 10h.

4. The high barrier polysilicon packaging film according to claim 2, characterized in that: In the A2 step, the amount ratio of maleic anhydride grafted polylactic acid, amino carbon nanotubes, dibutyltin dilaurate, and N,N-dimethylformamide is 11g:4g:1.5g:110mL; the molecular weight of the amino carbon nanotubes is 50,000; the flow rate of nitrogen is 150mL / min, and the passage time is 20min; the stirring speed is 500r / min; a dialysis bag with a molecular weight cutoff of 2000Da is selected, and the product is dialyzed in deionized water for 4 days, during which the deionized water is replaced 3 times a day; after dialysis, the sample is pre-frozen to -45°C and maintained for 3h, and then sublimated and dried for 30h under a vacuum degree of 15Pa.

5. The high barrier polysilicon packaging film according to claim 2, characterized in that: In the step A3, the amount ratio of carbon nanotube-modified polylactic acid, polybutylene adipate-terephthalate, diisopropylbenzene peroxide, and xylene is 12g:6g:0.8g:120mL; the flow rate of nitrogen is 180mL / min, and the time of nitrogen is 15min; the stirring speed is 550r / min; the rotary evaporation temperature is 60°C and the vacuum degree is 0.06MPa; The product was dried at 75°C and a vacuum degree of 0.09 MPa for 15 h.

6. The high barrier polysilicon packaging film according to claim 1, characterized in that: The modified silica aerogel is specifically prepared in the following steps: B1. Add silica aerogel to anhydrous ethanol, ultrasonically disperse the mixture for 35 minutes, add 3-aminopropyltrimethoxysilane to the suspension, place the reaction container in a constant temperature water bath, heat to 55° C., and stir to react for 3.5 hours; after the reaction is completed, use a sand core funnel to filter under reduced pressure, collect the solid product, wash and dry it to obtain amino silica aerogel; B2, adding the aminated silica aerogel to toluene, transferring the mixture to a three-necked flask, stirring and dispersing, adding glycidyl trimethylammonium chloride, heating the reaction system to 85°C and stirring for 4.5h; after the reaction is completed, stopping heating, cooling the reaction solution to room temperature, using a sand core funnel to perform vacuum filtration, collecting the solid product, washing, and drying to obtain quaternary ammonium salt modified silica aerogel; B3. Add the quaternary ammonium salt modified silica aerogel into anhydrous ethanol and ultrasonically disperse it for 35 minutes, add nanosilver sol into the suspension, continue ultrasonically dispersing it for 10 minutes, and then place the reaction container on a magnetic stirrer and stir the reaction at room temperature for 2.5 hours; after the reaction is completed, centrifuge and separate, collect the precipitated product, wash it, and dry it to obtain the final modified silica aerogel.

7. The high barrier polycrystalline silicon packaging film according to claim 6, characterized in that: In step B1, the amount ratio of silica aerogel, anhydrous ethanol and 3-aminopropyltrimethoxysilane is 12 g: 130 mL: 4 g; the specific surface area is 600 m 2 / g, an average pore size of 15nm silica aerogel; the stirring speed is 300r / min; the product is dried at 60°C and a vacuum degree of 0.08MPa for 12h; in the step B2, the amount ratio of the amino silica aerogel, toluene, and glycidyltrimethylammonium chloride is 11g:110mL:6g; the stirring speed is 350r / min; the washed solid product is dried at 70°C and a vacuum degree of 0.09MPa for 15h.

8. The high barrier polycrystalline silicon packaging film according to claim 6, characterized in that: In the step B3, the dosage ratio of quaternary ammonium salt modified silica aerogel, anhydrous ethanol and nano silver sol is 12g:130mL:4g; the stirring speed is 400r / min; the centrifugal separation speed is 5000r / min, and each centrifugation is 15min; the washed precipitated product is dried at 50°C and a vacuum degree of 0.07MPa for 24h.

9. A method for preparing a high barrier polysilicon packaging film, characterized in that: The specific steps include: S1. Add nano-montmorillonite and modified silica aerogel into a high-speed mixer and stir for 5 minutes. Then, add modified polylactic acid, ethylene-vinyl alcohol copolymer and polyvinylidene chloride in sequence and stir at an accelerated speed for 8 minutes. Then, add tributyl citrate, antioxidant 1010, UV absorber UV-531, nucleating agent NA-11, silane coupling agent KH550, vinyl trimethoxy silane and nano silver antibacterial agent and continue stirring for 7 minutes. Finally, add deionized water and stir at an accelerated speed for 15 minutes. S2, placing the polyester film in a plasma treatment device, treating it with oxygen plasma for 5 minutes, and immediately feeding the treated polyester film into the feeding area of ​​a casting machine, setting the temperature of the screw extruder to 150°C, setting the traction speed to 0.7 m / min, and casting the mixed slurry on the polyester film carrier through the casting machine, the casting speed is 0.7 m / min, and the casting thickness is 0.3 mm; S3. Send the wet polyester film after cast molding into a pre-drying box, and heat it with hot air circulation. The temperature is set to 50℃ and the drying time is 40min. The pre-dried film enters the main drying area, and the main drying area adopts segmented heating. The temperature of the first section is set to 60℃ and the drying time is 50min. The temperature of the second section is increased to 70℃ and the drying time is 40min. After the main drying is completed, send the film into a curing box for curing treatment. The temperature of the curing box is set to 110℃ and the curing time is 2h. After the curing is completed, the packaging film is slowly cooled to room temperature by a combination of air cooling and water cooling.

10. The method for preparing a high barrier polysilicon packaging film according to claim 9, characterized in that: In the step S1, the initial stirring speed is 500 r / min, the speed after acceleration is 600 r / min, and the speed after further acceleration is 800 r / min.