Degradable environment-friendly electrically insulating plastic packaging bag and preparation method thereof

Abstract

The application relates to the field of packaging materials, and particularly discloses a degradable environment-friendly electrically insulating plastic packaging bag and a preparation method thereof. The degradable environment-friendly electrically insulating plastic packaging bag comprises the following raw materials in parts by weight: 100 parts of polylactic acid, 1-4 parts of organic zirconium phosphate, 2-5 parts of hydrophobically modified cellulose nanocrystals, 4-10 parts of polyimide / aluminum fluoride composite nanofibers, 1-3 parts of a dispersing agent, 1-4 parts of an antioxidant, 3-5 parts of an inorganic filler, 1-3 parts of a slip agent, 1-3 parts of an antistatic agent and 3-5 parts of a flame retardant. The packaging bag can be used for articles with high requirements for electrically insulating properties, has strong electrically insulating capacity at high temperatures, and has high transparency and strong mechanical properties.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of packaging materials, in particular to a degradable environment-friendly electrically insulating plastic packaging bag and a preparation method thereof. BACKGROUND

[0002] The electrically insulating packaging bag is mainly used for packaging articles with requirements for electrically insulating performance, and the articles usually include electrical components, electronic devices and sensitive electronic devices, such as integrated circuits, transistors, resistors, transformers, capacitors, motors, hard disk drives, mainboards and the like, which need to avoid current leakage or static interference during working or storage. The electrically insulating packaging bag is usually made of materials with good electrically insulating performance, such as polyethylene, polypropylene, polystyrene, polyphenylene sulfide and the like, which can prevent the flow of electric charges under the action of an electric field, and thus have excellent electrically insulating performance.

[0003] However, the polymer insulating materials cannot be naturally degraded after being discarded, and can only be treated by burying or incineration, which pollutes the soil and produces harmful gases, polluting the air and the natural environment. Polylactic acid can be completely decomposed into carbon dioxide and water under the action of microorganism secreted enzymes in nature, and has no pollution to the environment, and is one of the most promising biodegradable polymers. Polylactic acid has electrically insulating performance, and has been applied to the packaging of electronic products. However, the heat distortion temperature of polylactic acid is relatively low, generally about 55 DEG C (non-crystalline state), and in a high temperature environment, polylactic acid may be deformed, resulting in changes in the structure of the material. In addition, in a high temperature environment, the movement of the polar functional groups such as ester groups on the polylactic acid molecular chain is increased, which may lead to the weakening of the interaction between the molecular chains, and more easily form a conductive channel or leak current, affecting the insulating performance of the packaging bag. In view of the above-mentioned related technologies, the inventors find that the insulating performance of polylactic acid at high temperature needs to be improved. SUMMARY

[0004] In order to increase the electrically insulating performance of the polylactic acid packaging bag at high temperature, the application provides a degradable environment-friendly electrically insulating plastic packaging bag and a preparation method thereof.

[0005] In the first aspect, the application provides a degradable environment-friendly electrically insulating plastic packaging bag, which adopts the following technical scheme: a degradable environment-friendly electrically insulating plastic packaging bag, comprising the following raw materials by weight: 100 parts of polylactic acid, 1-4 parts of organic zirconium phosphate, 2-5 parts of hydrophobically modified cellulose nanocrystals, 4-10 parts of polyimide / aluminum fluoride composite nanofibers, 1-3 parts of a dispersing agent, 1-4 parts of an antioxidant, 3-5 parts of an inorganic filler, 1-3 parts of a slip agent, 1-3 parts of an antistatic agent and 3-5 parts of a flame retardant.

[0006] By adopting the technical scheme, the polylactic acid with degradability is used as a base material, a small amount of organic zirconium phosphate and hydrophobic modified cellulose nanocrystals are mixed, and the polylactic acid-based packaging bag is modified in heat resistance by cooperating with polyimide / aluminum fluoride composite nanofibers. The organic zirconium phosphate plays a heterogeneous nucleation role in the polylactic acid matrix, and the thermal stability of the lamellar structure can improve the heat resistance and toughness of the polylactic acid. In addition, the lamellar structure provides a large number of nucleation sites for the polylactic acid, promotes the crystallization of the polylactic acid, and the polylactic acid molecular chain is arranged in order around the nucleation site to form a more perfect crystal structure. In addition, the increase of the nucleation site increases the crystallization rate of the polylactic acid, shortens the crystallization time, and faster reaches a higher crystallinity, improves the heat resistance. The lamellar structure of the organic zirconium phosphate forms a heat shield in the polylactic acid matrix, blocks the rapid transfer of heat, and when the polylactic acid is heated, the lamellar structure can attract and disperse heat, thereby delaying the thermal decomposition process. Through the interaction with the polylactic acid, the organic zirconium phosphate can change the molecular arrangement and packing mode of the polylactic acid, so that the glass transition temperature of the polylactic acid is improved, thereby enhancing the heat resistance. The organic zirconium phosphate can also enhance the tensile strength and impact strength of the polylactic acid and other mechanical properties, so that the polylactic acid not only has high heat resistance, but also has good mechanical properties. In addition, the organic zirconium phosphate does not change the chemical structure of the polylactic acid, so that the polylactic acid still maintains its original degradability, which meets the environmental protection requirements.

[0007] The cellulose nanocrystal is a kind of nanofiller with degradability, but due to the existence of a large number of hydrophilic hydroxyl groups on its surface, it has poor compatibility with the hydrophobic polylactic acid matrix, and it is easy to agglomerate in the polylactic acid matrix and difficult to disperse uniformly, so it needs to be hydrophobically modified. The dispersion and compatibility of the hydrophobically modified cellulose nanocrystal in the polylactic acid are improved, and it has good interfacial bonding with the polylactic acid, promotes the directional arrangement and crystallization of the polylactic acid molecular chain, inhibits the crystal growth of the polylactic acid molecule, reduces the scattering of the material, improves the transparency of the material, and fills the micro defects in the polylactic acid, effectively inhibits the crack propagation, and improves the toughness and elongation at break of the material. The polylactic acid has high heat resistance and good mechanical properties while maintaining high transparency. In addition, the hydrophobically modified cellulose nanocrystal is uniformly dispersed in the polylactic acid to form a dense network structure in the wrapping of the polylactic acid, which provides a barrier effect for the polylactic acid and improves the electrical insulation of the polylactic acid to a certain extent.

[0008] The aromatic polyimide has excellent mechanical properties, thermal stability and excellent dielectric properties, and the aluminum fluoride also has strong electrical insulation. In addition, the fluorine-containing property can also improve the hydrophobicity of the surface of the composite nanofiber, thereby enhancing the dispersion of the composite nanofiber in the polylactic acid, improving the interfacial action of the two, and enhancing the heat resistance, mechanical strength and electrical insulation capacity of the packaging bag.

[0009] Optionally, the hydrophobically modified cellulose nanocrystals comprise cellulose nanocrystals, tannic acid and octadecylamine in a mass ratio of 1:0.4-0.6:0.9-1.

[0010] By adopting the above technical solution, the tannic acid can be self-polymerized on the cellulose nanocrystals by oxidation to form a poly-tannic acid thin layer, which adheres to the surface of the cellulose nanocrystals and shields the hydroxyl groups. Then, the tannic acid and the octadecylamine undergo a Michael addition reaction. Since the octadecylamine has a higher thermal decomposition temperature, the thermal stability and hydrophobicity of the cellulose nanocrystals are improved, the cellulose nanocrystals are well dispersed in the polylactic acid matrix, more nucleation sites are provided, the crystallization process of the polylactic acid is completed faster, the mechanical properties of the packaging bag are significantly improved, the tensile strength and elongation at break are enhanced, and the improvement in the dispersity of the cellulose nanocrystals makes the crystal grain size smaller and the light transmittance higher.

[0011] Optionally, the method for preparing the hydrophobically modified cellulose nanocrystals is as follows:

[0012] The pH of a cellulose nanocrystal suspension with a concentration of 2-3 wt% is adjusted to 8-9, Tris buffer and tannic acid are added, and stirring is performed for 20-24 h to obtain an aqueous dispersion;

[0013] An anhydrous ethanol solution of octadecylamine is mixed with the aqueous dispersion, stirring is performed at 50-60℃ for 20-24 h, centrifugation is performed, the precipitate is collected, washed, and freeze-dried to obtain a pretreated cellulose nanocrystal powder;

[0014] The pretreated cellulose nanocrystal powder is dispersed in deionized water, ultrasonic dispersion is performed for 2-3 h, 3-aminopropyl trihydroxysilane modified boron nitride nanosheets are added, stirring is performed for 6-8 h, vacuum filtration is performed, drying is performed at 100-130℃, and grinding is performed. The mass ratio of the 3-aminopropyl trihydroxysilane modified boron nitride nanosheets to the pretreated cellulose nanocrystal powder is 0.1-0.2:1.

[0015] By adopting the technical scheme, the tannic acid is used to form a poly-tannin layer on the surface of the cellulose nanocrystal, and then reacts with octadecylamine to improve the heat resistance of the cellulose nanocrystal, and then the boron nitride nanosheet is used for further modification, the boron nitride nanosheet itself has good thermal stability and can improve the high-temperature resistance of the cellulose nanocrystal, the tannic acid not only has a Michael addition reaction with the octadecylamine, but also provides a negative charge, so as to be electrostatically combined with the boron nitride nanosheet containing a positive charge, so that the 3-aminopropyl trihydroxy silane modified boron nitride nanosheet can be combined with the pretreated cellulose nanocrystal to improve the strength of the cellulose nanocrystal, and meanwhile, the dispersion of the boron nitride nanosheet is improved, the agglomeration and condensation are reduced, the possibility of forming a heat-conducting network is increased, and the boron nitride is more difficult to slide out along the stretching direction in the stretching process of the packaging bag, which helps to improve the mechanical strength; the pretreated cellulose nanocrystal powder loaded with the boron nitride nanosheet can prevent the cellulose nanocrystal from penetrating under a strong electric field due to the two-dimensional structure and high insulation strength of the boron nitride nanosheet, when the boron nitride nanosheet is combined with the cellulose nanocrystal, the boron nitride nanosheet fills the gap between the molecular chains and forms a hydrogen bond with the cellulose nanocrystal, the structure of the whole system is more closely combined, the free volume is reduced, the movement of the molecular chains is effectively weakened, and the insulation performance of the composite material is improved.

[0016] Optionally, the organic zirconium phosphate is pretreated by blending the organic zirconium phosphate with poloxamer 407 and polycaprolactone at a mass ratio of 0.03-0.05:0.02-0.04:1, and then granulating.

[0017] By adopting the technical scheme, the organic zirconium phosphate pretreated by poloxamer 407 and polycaprolactone can further improve the heat resistance and mechanical strength of the polylactic acid, the addition of poloxamer 407 increases the movement ability of the polylactic acid molecular chain, promotes the nucleation and crystallization of the polylactic acid, and moreover, the melting point of poloxamer 407 is lower than that of polylactic acid, poloxamer 407 is in a liquefied state before polylactic acid is hot-melted, and has the same alpha methyl dihas similar phase solubility as the polylactic acid chain, thereby helping the local movement of the polylactic acid molecular chain, and causing the recrystallization of the polylactic acid segment with orientation or incomplete crystallization in the heating process, so that the polylactic acid crystallization is more complete and compact, polycaprolactone has good compatibility with polylactic acid, can form a blending system with adjustable degradation rate, and has certain electrical insulation, which can optimize the electrical insulation capacity of the packaging bag and improve the heat resistance of the polylactic acid.

[0018] Optionally, the polyimide / aluminum fluoride composite nanofiber is prepared by electrospinning a polyamide acid solution and an aluminum fluoride composite and then imidizing, and the mass ratio of the polyamide acid solution and the aluminum fluoride is 1:0.01-0.012.

[0019] By adopting the technical scheme, the polyamide acid nanofiber matrix is obtained by electrospinning of the polyamide acid, in the thermal imidization process, the amide bond is not broken to generate anhydride and amine, the Al-F bond in the aluminum fluoride reacts with the amine group NH2 to be combined in a covalent bond manner and is attached to the surface of the polyimide nanofiber, after the thermal imidization, the fluorine element is lost in the form of gas in the reaction process, so that the fluorine content is reduced, the environmental safety is increased, and due to the generation of the crosslinked structure, the tensile property is enhanced, meanwhile, the good dispersibility of the aluminum fluoride in the polyimide and the interface interaction between the polyimide and the aluminum fluoride make the mechanical property of the composite nanofiber be enhanced, the aluminum fluoride can also hinder the chain segment movement and reduce the thermal decomposition rate of the composite nanofiber, the polyimide and the aluminum fluoride both have strong electric insulation capacity, so that the heat resistance of the polylactic acid is improved and the electric insulation capacity is increased.

[0020] Optionally, the inorganic filler is porous silica.

[0021] By adopting the technical scheme, the porous silica as the filler can improve the crystallization rate of the polylactic acid, so that the heat resistance of the polylactic acid is improved, but the porous structure may affect the light transmission effect of the packaging bag.

[0022] Optionally, the porous silica is pretreated as follows:

[0023] The porous silica is immersed in a polyglycolic acid solution under negative pressure, is filtered and dried to obtain modified porous silica;

[0024] The modified porous silica is immersed in a blending liquid prepared by mixing PMMA emulsion and deionized water at a mass ratio of 1:1, is filtered and dried after being immersed for 3-5 min to obtain an intermediate;

[0025] The intermediate is mixed with trimethoxy(1H, 1H, 2H, 2H-heptadecafluorodecyl) silane and deionized water, is heated to 80-90℃ in a sealed environment, and is reacted for 3-4 h.

[0026] By adopting the above technical solution, the porous structure of the porous silica will produce light scattering, affecting the transparency of the packaging bag, and the pores of the porous silica are filled with a polyglycolic acid solution with higher light transmittance under negative pressure, thereby improving the transparency of the packaging film, and then the transparency of the porous silica is further improved by using an optically transparent material, and the hydrophobic properties of the porous silica are improved. Finally, trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane is deposited on the surface of the porous silica by a vapor phase method for hydrophobic modification, which effectively reduces the surface energy of the porous silica and thus improves its hydrophobicity. The surface activity of the hydrophobically modified porous silica is reduced, and it can be better dispersed in the polylactic acid matrix. The interfacial compatibility between the two is improved, forming a tightly connected whole, which plays a role in stress transmission, thereby improving the mechanical properties of the packaging bag to a certain extent, and can refine the grains, thereby improving the transmittance of the packaging bag and enhancing the light transmittance of the material.

[0027] Optionally, the density of the polylactic acid is 1.24-1.28 g / cm 3 .

[0028] Optionally, the dispersant is selected from polyethylene glycol or acetyl tributyl citrate, the antioxidant is selected from antioxidant 1010 or antioxidant 168, the flame retardant is ammonium polyphosphate, the lubricant is ethylene bis-12-hydroxystearamide, and the antistatic agent is ester quaternary ammonium salt.

[0029] In a second aspect, the present application provides a method for preparing a biodegradable and environmentally friendly electrically insulating plastic packaging bag, which adopts the following technical solution:

[0030] A method for preparing a degradable and environmentally friendly electrically insulating plastic packaging bag comprises the following steps:

[0031] The electrical insulating plastic packaging bag is prepared by uniformly mixing polylactic acid, organic zirconium phosphate, hydrophobically modified cellulose nanocrystals, polyimide / aluminum fluoride composite nanofibers, antistatic agent, dispersant, antioxidant, inorganic filler, lubricant and flame retardant, heating and hot melting, casting film, cutting and heat sealing to make bags.

[0032] In summary, this application has the following beneficial effects:

[0033] 1. Since the present application adopts polylactic acid as the base material and incorporates raw materials such as organic zirconium phosphate, hydrophobically modified cellulose nanocrystals and polyimide / aluminum fluoride composite nanofibers, the heat resistance of the packaging bag is effectively improved, making it less likely to produce thermal deformation when used at high temperatures, and reducing the movement of molecules at high temperatures, reducing conductive channels or current leakage, improving the insulation capacity of the packaging bag under high temperature use, and at the same time enhancing the tensile strength of the packaging bag.

[0034] 2, In the application, the hydrophobically modified cellulose nanocrystals are prepared by mixing 3-aminopropyl trihydroxysilane modified boron nitride nanosheets after grafting octadecylamine on tannic acid, which reduces the movement of molecular chains, enhances the heat resistance and insulation performance of the hydrophobically modified cellulose nanocrystals, and improves the mechanical strength.

[0035] 3, In the application, polyamide acid solution and aluminum fluoride are mixed and then electrospun and heat imidized to prepare polyimide / aluminum fluoride composite nanofibers. Both polyimide and aluminum fluoride have excellent electrical insulation ability and strong heat resistance, which can improve the heat resistance and electrical insulation ability of the packaging bag.

[0036] 4, In the application, porous silica is used as a filler, and polyglycolic acid solution is used for impregnation, PMMA emulsion is used for hydrophobic modification, and trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane vapor deposition is used for surface modification of porous silica, which reduces the scattering of light by porous silica, increases the dispersibility and compatibility of porous silica in polylactic acid, and improves the transparency and mechanical strength of the packaging bag. DETAILED DESCRIPTION

[0037] The following examples further illustrate the application.

[0038] Preparation examples 1-6 of hydrophobically modified cellulose nanocrystals

[0039] Preparation example 1: (1) 20 g of cellulose nanocrystals were dispersed in deionized water and ultrasonically dispersed for 10 min to prepare a cellulose nanocrystal suspension with a concentration of 2 wt%, the pH was adjusted to 8 with sodium hydroxide solution, and 4 g of tris(hydroxymethyl)aminomethane (Tris) buffer was added, 12 g of tannic acid was added, stirred at room temperature for 24 h to prepare a water dispersion, and the cellulose nanocrystals were selected from Zhejiang Jinjiahao Green Nanomaterials, with a catalog number of CNC;

[0040] (2) 20 g of octadecylamine was dissolved in 1000 ml of anhydrous ethanol, mixed with the water dispersion, stirred at 50°C for 24 h, centrifuged, and the lower precipitate was collected, washed with ethanol, and freeze-dried to prepare a pretreated cellulose nanocrystal powder;

[0041] (3) The pretreated cellulose nanocrystal powder is dispersed in deionized water, ultrasonic dispersion for 2h, 3-aminopropyl trihydroxysilane modified boron nitride nanosheet is added, stirring for 6h, vacuum filtration, drying at 130℃, crushing, grinding, the mass ratio of 3-aminopropyl trihydroxysilane modified boron nitride nanosheet and pretreated cellulose nanocrystal powder is 1:0.1, the preparation method of 3-aminopropyl trihydroxysilane modified boron nitride nanosheet is as follows: boron nitride powder is dispersed in isopropyl alcohol to prepare a solution with a concentration of 4mg / ml, ultrasonic treatment for 7h to obtain a suspension, vacuum filtration, washed with ethanol and deionized water, dried to obtain boron nitride nanosheet, 100mg boron nitride nanosheet is dispersed in 100ml ethanol, 0.1ml 3-aminopropyl trihydroxysilane is added, stirred uniformly at 60℃ for 24h, vacuum filtration, washed with ethanol and deionized water and dried.

[0042] Preparation Example 2: (1) 20g cellulose nanocrystal is dispersed in deionized water, ultrasonic dispersion for 10min, a cellulose nanocrystal suspension with a concentration of 2wt% is prepared, the pH is adjusted to 9 with sodium hydroxide solution, and 4g tris(hydroxymethyl)aminomethane (Tris) buffer is added, 8g tannic acid is added, stirring at room temperature for 20h to prepare an aqueous dispersion, the cellulose nanocrystal is selected from Zhejiang Jinjiahao Green Nanometer Material, the item number is CNC;

[0043] (2) 18g octadecylamine is dissolved in 1000ml anhydrous ethanol, mixed with the aqueous dispersion, stirred at 60℃ for 20h, centrifuged, the lower precipitate is collected, washed with ethanol, freeze-dried to obtain pretreated cellulose nanocrystal powder;

[0044] (3) The pretreated cellulose nanocrystal powder is dispersed in deionized water, ultrasonic dispersion for 3h, 3-aminopropyl trihydroxysilane modified boron nitride nanosheet is added, stirring for 8h, vacuum filtration, drying at 100℃, crushing, grinding, the mass ratio of 3-aminopropyl trihydroxysilane modified boron nitride nanosheet and pretreated cellulose nanocrystal powder is 1:0.2, the preparation method of 3-aminopropyl trihydroxysilane modified boron nitride nanosheet is as follows: boron nitride powder is dispersed in isopropyl alcohol to prepare a solution with a concentration of 4mg / ml, ultrasonic treatment for 7h to obtain a suspension, vacuum filtration, washed with ethanol and deionized water, dried to obtain boron nitride nanosheet, 100mg boron nitride nanosheet is dispersed in 100ml ethanol, 0.1ml 3-aminopropyl trihydroxysilane is added, stirred uniformly at 60℃ for 24h, vacuum filtration, washed with ethanol and deionized water and dried.

[0045] Preparation Example 3: (1) Disperse 20 g of cellulose nanocrystals in deionized water and ultrasonically disperse for 10 min to obtain a cellulose nanocrystal suspension with a concentration of 2 wt%. Adjust the pH to 9 with sodium hydroxide solution, add 4 g of tris(hydroxymethyl)aminomethane (Tris) buffer, add 8 g of tannic acid, stir at room temperature for 20 h to obtain an aqueous dispersion, vacuum filter, and dry to constant weight. The cellulose nanocrystals are selected from Zhejiang Jinjiahao Green Nanomaterials, and the product number is CNC.

[0046] Preparation Example 4: (1) Disperse 20 g of cellulose nanocrystals in deionized water and ultrasonically disperse for 10 min to obtain a cellulose nanocrystal suspension with a concentration of 2 wt%. The cellulose nanocrystals are selected from Zhejiang Jinjiahao Green Nanomaterials, with the product number CNC; (2) Dissolve 20 g of octadecylamine in 1000 ml of anhydrous ethanol, mix with the cellulose nanocrystal suspension, stir at 50°C for 24 h, centrifuge, collect the lower precipitate, wash with ethanol, and freeze-dry.

[0047] Preparation Example 5: The difference from Preparation Example 1 is that 3-aminopropyltrihydroxysilane-modified boron nitride nanosheets are not added.

[0048] Preparation Example 6: The difference from Preparation Example 1 is that the boron nitride nanosheets are not modified with 3-aminopropyltrihydroxysilane.

[0049] Example

[0050] Example 1: A biodegradable and environmentally friendly electrical insulating plastic packaging bag. The raw material dosage is shown in Table 1, wherein the density of polylactic acid is 1.24 g / cm 3, the hydrophobically modified cellulose nanocrystal is made by Preparation Example 1, the dispersing agent is polyethylene glycol 6000, the antioxidant is antioxidant 1010, the slip agent is ethylene bis-12-hydroxystearamide, the antistatic agent is ester-based quaternary ammonium salt, which is selected from Shandong Hengrui, model TEP-90, the flame retardant is ammonium polyphosphate, the inorganic filler is porous silica, which is selected from Foshan Oulite New Material, model SDK-2480, the particle size is 2 μm, the organic zirconium phosphate is prepared by pre-intercalating zirconium phosphate with methylamine and then intercalating with octadecyl trimethyl ammonium chloride, the specific method is as follows: 5.82 g of zirconium phosphate is dispersed in 300 ml of deionized water, 12 g of 25% concentration methylamine solution is added, and the reaction is carried out at room temperature for 72 h, then filtered, washed with deionized water for 3 times, and dried at 90℃ under vacuum for 24 h to obtain methylamine pre-intercalated zirconium phosphate; the methylamine pre-intercalated zirconium phosphate is prepared into a suspension with a concentration of 5wt%, 2.5 g of octadecyl trimethyl ammonium chloride is added, stirred at 70℃ for 3 h, then centrifuged, the precipitate is washed with 50% ethanol solution until there is no chloride ion (tested with 0.1 mol / l silver nitrate solution), dried at 65℃ under vacuum for 24 h, and ground through a 200 mesh sieve, the polyimide / aluminum fluoride composite nanofiber is prepared by electrospinning a polyamide acid solution and an aluminum fluoride compound and then imidizing, the specific method is as follows: 113.44 g of a mixture of N,N-dimethylacetamide and tetrahydrofuran is mixed with 0.02 mol of diamine monomer (the molar ratio of 2,2'-dimethylbenzidine and 4,4-diaminodiphenyl ether is 5:5), stirred until completely dissolved, then 0.02 mol of 3,3',4,4'-biphenyl tetracarboxylic dianhydride is added, refluxed and stirred under ice water bath and nitrogen protection for 12 h to prepare a polyamide acid solution with a concentration of 15wt%, a mixture of N,N-dimethylacetamide and tetrahydrofuran is added to dilute the polyamide acid solution to obtain a polyamide acid solution with a concentration of 8wt%, aluminum fluoride is added, the mass ratio of the polyamide acid solution to the aluminum fluoride is 1:0.01, stirred for 2 h, and then placed to defoam to obtain a spinning solution, the nanofiber matrix is obtained after electrospinning, and then imidization is carried out to obtain the composite nanofiber, the spinning voltage is 15 kV, the receiving distance is 20 cm, and the spinning rate is 0.6 ml / h, the imidization process is as follows: heated to 150℃ at a speed of 5℃ / min under nitrogen atmosphere, kept for 120 min, heated to 250℃ at a speed of 4℃ / min, kept for 60 min, and then heated to 370℃ at a speed of 3℃ / min, kept for 30 min.

[0051] The preparation method of the above-mentioned degradable environment-friendly electrically insulating plastic packaging bag comprises the following steps:

[0052] The polylactic acid, organic zirconium phosphate, hydrophobically modified cellulose nanocrystal, polyimide / aluminum fluoride composite nanofiber, antistatic agent, dispersant, antioxidant, inorganic filler, slip agent and flame retardant are mixed uniformly, heated to 220℃ hot melt, cast into a film with a thickness of 220μm, cut, heat sealed at 200℃ to make a bag, and an electrically insulating plastic packaging bag is prepared.

[0053] Table 1 Raw material amount of degradable environment-friendly electrically insulating plastic packaging bag in examples 1-4

[0054]

[0055]

[0056] Example 2: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the raw material amount is shown in Table 1, and the hydrophobically modified cellulose nanocrystal is prepared by Preparation Example 2, and the mass ratio of polyamic acid solution to aluminum fluoride in the polyimide / aluminum fluoride nanofiber is 1:0.12.

[0057] Examples 3-4: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the raw material amount is shown in Table 1,

[0058] Example 5: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the hydrophobically modified cellulose nanocrystal is prepared by Preparation Example 3.

[0059] Example 6: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the hydrophobically modified cellulose nanocrystal is prepared by Preparation Example 4.

[0060] Example 7: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the hydrophobically modified cellulose nanocrystal is prepared by Preparation Example 5.

[0061] Example 8: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the hydrophobically modified cellulose nanocrystal is prepared by Preparation Example 6.

[0062] Example 9: A degradable environment-friendly electrically insulating plastic packaging bag, which is different from example 1 in that the organic zirconium phosphate is pretreated as follows: the organic zirconium phosphate is blended with poloxamer 407 and polycaprolactone at a mass ratio of 0.05:0.04:1, heated to 90℃, melted, extruded, and granulated, the polycaprolactone has a melt index (160℃, 5kg) of 3g / 10min and an average molecular weight of 80000g / mol, and is selected from American Sowei, model 6800.

[0063] Example 10: A degradable environmentally friendly electrically insulating plastic packaging bag, which is different from example 1 in that the organic zirconium phosphate is pretreated as follows: the organic zirconium phosphate is blended with poloxamer 407 and polycaprolactone at a mass ratio of 0.03:0.02:1, then heated to 90°C, melted, extruded, and granulated, the polycaprolactone has a melt index (160°C, 5kg) of 3g / 10min and an average molecular weight of 80000g / mol, and is selected from the United States Sowei, model 6800.

[0064] Example 11: A degradable environmentally friendly electrically insulating plastic packaging bag, which is different from example 10 in that the organic zirconium phosphate is pretreated as follows: the organic zirconium phosphate is blended with polycaprolactone at a mass ratio of 0.03:1, then heated to 90°C, melted, extruded, and granulated, the polycaprolactone has a melt index (160°C, 5kg) of 3g / 10min and an average molecular weight of 80000g / mol, and is selected from the United States Sowei, model 6800.

[0065] Example 12: A degradable environmentally friendly electrically insulating plastic packaging bag, which is different from example 10 in that the organic zirconium phosphate is pretreated as follows: the organic zirconium phosphate is blended with poloxamer 407 at a mass ratio of 0.03:0.02, then heated to 90°C, mixed uniformly, and crushed.

[0066] Example 13: A degradable environmentally friendly electrically insulating plastic packaging bag, which is different from example 10 in that the porous silica is pretreated as follows:

[0067] ① The porous silica is immersed in a polyglycolic acid solution with a concentration of 15wt% under negative pressure of 0.05MPa for 20min, then depressurized, filtered, and dried to obtain modified porous silica, the polyglycolic acid solution is prepared by mixing 15g of polyglycolic acid with a mixture of tetrahydrofuran and N,N-dimethylformamide in a volume ratio of 1:1, and the polyglycolic acid is selected from China Wuhan Lalanbai Medicine, item number inb-pga;

[0068] ② The modified porous silica is immersed in a blending liquid prepared by mixing PMMA emulsion with a concentration of 26wt% (prepared by mixing 26g of PMMA and dimethylformamide) and deionized water at a mass ratio of 1:1 to obtain an intermediate, the PMMA is selected from Taiwan Qimei, model CM-211;

[0069] ③ The intermediate is mixed with trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane and deionized water at a mass ratio of 1:0.5:2, and heated to 80°C in a sealed environment for 4h.

[0070] Example 14: A degradable and environmentally friendly electrically insulating plastic packaging bag. The difference from Example 13 is that the porous silica is not impregnated with the polyglycolic acid solution, but is immersed in the blended liquid for 5 minutes, filtered and dried, and then mixed with trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane and deionized water in a ratio of 1:0.5:2, and reacted at 80°C for 4 hours.

[0071] Example 15: A degradable and environmentally friendly electrically insulating plastic packaging bag. The difference from Example 13 is that the modified porous silica is not impregnated with PMMA emulsion, and the modified porous silica is mixed with trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane and deionized water in a ratio of 1:0.5:2 at 80°C for 4 hours.

[0072] Example 16: A degradable and environmentally friendly electrically insulating plastic packaging bag, which differs from Example 13 in that the intermediate is not mixed with trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane and deionized water in a ratio of 1:0.5:2 at 80°C for 4 hours.

[0073] Comparative Example

[0074] Comparative Example 1: A degradable and environmentally friendly electrically insulating plastic packaging bag, which differs from Example 1 in that no hydrophobically modified cellulose nanocrystals are added.

[0075] Comparative Example 2: A degradable and environmentally friendly electrically insulating plastic packaging bag, which differs from Example 1 in that an equal amount of cellulose nanocrystals is used to replace the hydrophobically modified cellulose nanocrystals.

[0076] Comparative Example 3: A degradable and environmentally friendly electrically insulating plastic packaging bag, which differs from Example 1 in that no organic zirconium phosphate is added.

[0077] Comparative Example 4: A degradable and environmentally friendly electrically insulating plastic packaging bag, which differs from Example 1 in that no polyimide / aluminum fluoride composite nanofibers are added.

[0078] Performance testing

[0079] 1. Tensile strength: Tested in accordance with GB / T13022-1991 "Test method for tensile properties of plastic films", with a tensile speed of 5 mm / min and a clamp distance of 50 mm.

[0080] 2. Light transmittance: A visible light spectrophotometer (Shanghai Youke Instrument, Model 723) was used to test the light transmittance of the packaging bag. The detection wavelength was 600 nm, the scanning speed was 1 nm / min, the interval was set to 10 nm, and air was used as the collection background for the test characterization.

[0081] 3. Initial decomposition temperature: The thermal stability was tested by using a German NETZSCH TG-209F3 thermogravimetric analyzer. About 8 mg of each sample was selected and heated from 25°C to 800°C at a heating rate of 10°C / min under nitrogen flow. The initial decomposition temperature of the material during the test was recorded.

[0082] 4. Volume resistivity: The test was carried out according to GB / T15662-1995 "Conductive, antistatic rate volume resistivity test method" at 60°C.

[0083] 5. Water contact angle: A sample with a size of 10 mm x 10 mm was prepared. The hydrophobicity of the packaging bag was characterized using a contact angle measuring instrument (Germany OCA20). A micro pillow was used to drop water droplets on the packaging bag. The liquid droplets were 3 μL of deionized water. The water contact angle was measured. Each sample was tested three times, and the average value was taken.

[0084] 6. Degradation rate: A packaging bag sample with a diameter of 10 cm and a mass of about 1.5 g was prepared. The sample mass and size were highly consistent to ensure the comparability of the experiment. The soil was selected. The sample was buried below the soil surface. After the sample was placed, the soil was covered and the sample was fully contacted with the soil. The sample was buried for 120 days. The sample was taken out, washed, and then dried in a blast drying oven and weighed. The mass change before and after burial was compared by mass measurement. The degradation performance of the sample in the soil environment was evaluated by the mass change rate.

[0085] Table 2 Performance test of degradable environmentally friendly electrically insulating plastic packaging bag

[0086]

[0087]

[0088] It can be seen from the data in Examples 1-4 and Table 2 that the packaging bags prepared in Examples 1-4 have high volume resistivity at 60°C, high insulation performance, high tensile strength, high light transmittance, high heat resistance, high water contact angle, high hydrophobicity, and can be degraded, which is more environmentally friendly.

[0089] In Example 5, the hydrophobically modified cellulose nanocrystals prepared in Preparation Example 3 were used. Compared with Preparation Example 1, only tannic acid was used to coat the cellulose nanocrystals in Preparation Example 3. The cellulose nanocrystals contain a poly-tannic acid layer on the surface, which affects the compatibility with substrates such as polylactic acid. The tensile strength of the packaging bag is reduced, the light transmittance and water contact angle are reduced, the degradation rate of the material is increased due to the increase in hydrophilicity, the heat resistance is weakened, and the electrical insulation performance is not obviously changed.

[0090] The hydrophobically modified cellulose nanocrystals prepared in Example 6 were used, and compared with Example 1, only octadecylamine was used to modify the cellulose nanocrystals. It can be seen that the packaging bag has good hydrophobicity, degradability and light transmittance, but the heat resistance is slightly decreased.

[0091] The hydrophobically modified cellulose nanocrystals prepared in Example 7 were used, and compared with Example 1, no 3-aminopropyl trihydroxysilane modified boron nitride nanosheet was added in Example 5. Compared with Example 1, the packaging bag prepared in Example 7 has increased transparency, accelerated degradation rate, significantly decreased volume resistivity, weakened electrical insulation capacity, weakened tensile strength and heat resistance.

[0092] Example 8 uses hydrophobically modified cellulose nanocrystals prepared in Example 6, compared with Example 1, the data in Table 2 shows that the tensile strength of the packaging bag prepared in Example 8 is slightly decreased, the hydrophobicity is weakened, and the light transmittance and heat resistance are decreased.

[0093] Example 9 and Example 10 use poloxamer 407 and polycaprolactone to pretreat organic zirconium phosphate compared with Example 1, as shown in Table 2, the volume resistivity of the packaging bag prepared in Example 9 and Example 10 is increased, the tensile strength is increased, the degradation rate is increased, the heat resistance temperature is increased, and the performance is improved.

[0094] Example 11 and Example 12 do not use poloxamer 407 and polycaprolactone respectively compared with Example 10, it can be seen that the performance of the packaging bag prepared in Example 11 and Example 12 has different changes in heat resistance, degradation capacity, tensile strength and other performances.

[0095] Example 13 also uses polyglycolic acid solution and PMMA emulsion, trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl) silane and other series of pretreatment for porous silica compared with Example 10, as shown in Table 2, the transparency of the packaging bag prepared in Example 13 is significantly increased, the hydrophobicity is enhanced, the degradation rate is slightly decreased, but still retains a high degradation rate, the tensile strength is increased, the light transmittance is increased, the transparency is enhanced, and the heat resistance is increased.

[0096] Example 14 does not immerse porous silica in polyglycolic acid solution compared with Example 13, as shown in Table 2, the transparency of the packaging bag prepared in Example 14 is significantly decreased, the tensile strength is decreased, in Example 15, the modified porous silica is not soaked with PMMA emulsion, and in Example 16, the intermediate is not mixed with trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl) silane, it can be seen that the heat resistance of the packaging bag prepared in Example 15 and Example 16 is slightly decreased, the electrical insulation capacity is decreased, and the transparency is poor.

[0097] In the comparative example 1, no hydrophobically modified cellulose nanocrystal is added, and the data in Table 2 shows that the heat resistance of the packaging bag is reduced, the tensile strength is weakened, the transparency is decreased, and the electrical insulation is weakened. In the comparative example 2, cellulose nanocrystal is used to replace the hydrophobically modified cellulose nanocrystal, and the performance of the packaging bag such as the tensile strength is decreased, but is still higher than that of the comparative example 1.

[0098] In the comparative example 3, no organic zirconium phosphate is added compared with the example 1, and the data in Table 2 shows that the heat resistance of the packaging bag is reduced, the tensile strength is weakened, the degradation ability is weakened, but the transparency is slightly increased.

[0099] In the comparative example 4, no polyimide / aluminum fluoride composite nanofiber is added, and compared with the example 1, the tensile strength is decreased, the light transmittance is increased, but the heat resistance is weakened, and the electrical insulation is decreased.

[0100] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, but as long as the modifications are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A degradable environment-friendly electrically insulating plastic packaging bag, characterized in that, The raw materials include 100 parts of polylactic acid, 1-4 parts of organic zirconium phosphate, 2-5 parts of hydrophobically modified cellulose nanocrystals, 4-10 parts of polyimide / aluminum fluoride composite nanofibers, 1-3 parts of a dispersing agent, 1-4 parts of an antioxidant, 3-5 parts of an inorganic filler, 1-3 parts of a slip agent, 1-3 parts of an antistatic agent, and 3-5 parts of a flame retardant. The organic zirconium phosphate is prepared by pre-intercalating zirconium phosphate with methylamine and then intercalating with octadecyl trimethyl ammonium chloride. The polyimide / aluminum fluoride composite nanofiber is prepared by electrospinning polyamide acid solution and aluminum fluoride composite and then imidizing. The hydrophobically modified cellulose nanocrystal is prepared by the following method: The pH of a cellulose nanocrystal suspension with a concentration of 2-3 wt% is adjusted to 8-9, Tris buffer and tannic acid are added, and stirring is performed for 20-24 h to obtain an aqueous dispersion; an anhydrous ethanol solution of octadecylamine is mixed with the aqueous dispersion, stirring is performed at 50-60°C for 20-24 h, centrifugation is performed, the precipitate is collected, and washing, freeze-drying are performed to obtain pretreated cellulose nanocrystal powder; the pretreated cellulose nanocrystal powder is dispersed in deionized water, ultrasonic dispersion is performed for 2-3 h, 3-aminopropyl trihydroxy silane modified boron nitride nanosheets are added, stirring is performed for 6-8 h, vacuum filtration is performed, drying is performed at 100-130°C, and grinding is performed, with the mass ratio of 3-aminopropyl trihydroxy silane modified boron nitride nanosheets to pretreated cellulose nanocrystal powder being 0.1-0.2:

1.

2. The degradable environment-friendly electrically insulating plastic packaging bag according to claim 1, characterized in that: The hydrophobically modified cellulose nanocrystal includes cellulose nanocrystals, tannic acid, and octadecylamine at a mass ratio of 1:0.4-0.6:0.9-1.

3. The degradable environment-friendly electrically insulating plastic packaging bag according to claim 1, characterized in that: The organic zirconium phosphate is pretreated by blending the organic zirconium phosphate with poloxamer 407 and polycaprolactone at a mass ratio of 0.03-0.05:0.02-0.04:1 and then granulating.

4. The degradable environment-friendly electrically insulating plastic packaging bag according to claim 1, characterized in that: The inorganic filler is porous silica.

5. The degradable environment-friendly electrically insulating plastic packaging bag according to claim 4, characterized in that: The porous silica is pretreated by the following method: The porous silica is immersed in a polyglycolic acid solution under negative pressure, suction filtration and drying are performed to obtain modified porous silica; The modified porous silica is immersed in a blending solution prepared by mixing PMMA emulsion and deionized water at a mass ratio of 1:1, filtration and drying are performed after immersion for 3-5 min to obtain an intermediate; The intermediate is mixed with trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane and deionized water, and the temperature is raised to 80-90°C in a sealed environment, and the reaction is performed for 3-4 h.

6. The degradable environment-friendly electrically insulating plastic packaging bag according to claim 1, characterized in that: The density of the polylactic acid is 1.24-1.28 g / cm 3 .

7. The degradable environment-friendly electrically insulating plastic packaging bag according to claim 1, characterized in that: The dispersing agent is selected from polyethylene glycol or acetyl tri-butyl citrate, the antioxidant is selected from antioxidant 1010 or antioxidant 168, the flame retardant is ammonium polyphosphate, the slip agent is ethylene bis-12-hydroxystearamide, and the antistatic agent is ester-based quaternary ammonium salt.

8. The method of producing the degradable environment-friendly electrically insulating plastic packaging bag according to any one of claims 1-7, characterized in that: The method includes the following steps: The polylactic acid, organic zirconium phosphate, hydrophobically modified cellulose nanocrystals, polyimide / aluminum fluoride composite nanofiber, antistatic agent, dispersing agent, antioxidant, inorganic filler, slip agent, and flame retardant are uniformly mixed, heated and melted, cast into a film, cut, heat-sealed, and bagged to obtain an electrically insulating plastic packaging bag.

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