A multifunctional polyethylene breathable film and its preparation method

Abstract

This application relates to the field of polyethylene films, and specifically discloses a multifunctional polyethylene breathable film and a preparation method thereof. The raw materials thereof include the following components by weight percentage: 15%-30% of linear low-density polyethylene, 15%-40% of metallocene linear low-density polyethylene, 5%-10% of low-density polyethylene, 30-50% of breathable masterbatch, 2%-10% of antistatic masterbatch, 2-10% of antibacterial masterbatch, 5-10% of flame retardant masterbatch, and 2-5% of color masterbatch. The preparation method of the multifunctional polyethylene breathable film comprises the following steps: mixing, melt-extruding, blow molding, drawing, stretching into a film, and corona treating linear low-density polyethylene, metallocene linear low-density polyethylene, low-density polyethylene, breathable masterbatch, antistatic masterbatch, antibacterial masterbatch, flame retardant masterbatch, and color masterbatch according to the formula amount. The obtained breathable film not only has good air permeability and mechanical properties, but also has excellent antistatic, flame retardant and antibacterial functions.

Description

Technical Field

[0001] This application relates to the technical field of polyethylene films, and more specifically, it relates to a multifunctional polyethylene breathable film and a preparation method thereof. Background Art

[0002] Polyethylene is a non-toxic, low-temperature resistant and chemically stable thermoplastic resin. Polyethylene film is a composite polymer material made with polyethylene as the base material and adding fillers and additives. Polyethylene films are widely used in industries such as chemical engineering, medical treatment, and food, and have good development and expansion prospects. Polyethylene films are subdivided into multiple types according to different functions, and currently, the widely used polyethylene breathable film in the market.

[0003] Currently, the polyethylene breathable film is prepared from the following raw materials by mass percentage: 45 - 55% of calcium carbonate powder, 1 - 8% of compatibilizing flow modifier, 1 - 5% of processing aid, 0.1 - 1% of anti-aging agent, 25 - 35% of metallocene polyethylene, 5 - 15% of linear low-density polyethylene, 5 - 10% of low-density polyethylene; the calcium carbonate powder is calcium carbonate ultrafine powder with a particle diameter less than 60nm and surface modified by a coupling agent. Using a polyethylene blend and combining corresponding modified calcium carbonate particles and compatibilizing flow modifier can effectively improve the mechanical properties, low grammage, and low-temperature toughness of the breathable film.

[0004] When the above polyethylene breathable film is applied to protective clothing in the medical industry, it is found that the product is prone to generating static electricity and catching fire during use, and cannot play a good antibacterial role, failing to meet the actual needs of users. Summary of the Invention

[0005] This application provides a multifunctional polyethylene breathable film and a preparation method thereof. The prepared breathable film not only has good air permeability but also has excellent antistatic, flame-retardant, and antibacterial functions, and can meet different functional requirements of users for the breathable film.

[0006] In the first aspect, a multifunctional polyethylene breathable film provided by this application adopts the following technical solution: A multifunctional polyethylene breathable film, comprising the following raw materials by weight percentage: 15% - 30% of linear low-density polyethylene, 15% - 20% of metallocene linear low-density polyethylene, 5% - 10% of low-density polyethylene, 30 - 50% of breathable masterbatch, 2% - 10% of antistatic masterbatch, 2 - 10% of antibacterial masterbatch, 5 - 10% of flame-retardant masterbatch, and 2 - 5% of color masterbatch.

[0007] Metallocene linear low-density polyethylene (LLDPE) has a low melting point and offers excellent toughness, transparency, and hot tack. It also has high softening and melting temperatures, along with excellent resistance to environmental stress cracking, impact strength, and tear resistance. LDPE also boasts excellent chemical stability, flexibility, extensibility, electrical insulation, transparency, ease of processing, and moderate breathability. Compounding LLDPE, LLDPE, and LDPE facilitates system balance and excellent processing performance, thereby improving the mechanical properties of the product. When combined with a breathable masterbatch, it not only enhances the product's breathability but also ensures more uniform ventilation. When combined with an antistatic masterbatch, it effectively reduces the product's surface resistance and imparts excellent antistatic properties. It also synergizes with a flame-retardant masterbatch to enhance its flame retardancy. The antibacterial masterbatch exhibits excellent antibacterial properties against Escherichia coli and Staphylococcus aureus, meeting the diverse functional requirements of breathable membranes.

[0008] Furthermore, the breathable masterbatch comprises the following raw materials in percentage by weight: 40-55% polyethylene, 40-56% calcium carbonate, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent.

[0009] Furthermore, the antistatic masterbatch comprises the following raw materials in percentage by weight: 55-67% polyethylene, 30-41% antistatic agent, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent.

[0010] Furthermore, the antibacterial masterbatch comprises the following raw materials in weight percentage: 40-60% polyethylene, 28-50% calcium carbonate, 2-10% antibacterial agent, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent.

[0011] Furthermore, the flame retardant masterbatch comprises the following raw materials in percentage by weight: 40-80% polyethylene, 15%-50% bismaleimide, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent.

[0012] Furthermore, the antioxidant is antioxidant 1010, antioxidant 168 or antioxidant 1076.

[0013] Furthermore, the lubricant is stearate; specifically, the lubricant can be zinc stearate or calcium stearate.

[0014] The anti-yellowing agent is a hydrazide anti-yellowing agent; further anti-yellowing agent is adipic acid dihydrazide.

[0015] Further, the polyethylene includes 15%-40% linear low-density polyethylene, 10%-20% metallocene linear low-density polyethylene, and 5%-15% low-density polyethylene.

[0016] By adopting the above technical solution, during the preparation of the breathable masterbatch, antistatic masterbatch, antibacterial masterbatch, and flame retardant masterbatch, linear low-density polyethylene, metallocene linear low-density polyethylene, and low-density polyethylene are selected for compounding, further improving the compatibility and processing performance between the raw material components, and at the same time improving the mechanical properties of the product.

[0017] Through research and experiments, it is found that using bismaleimide as the flame retardant can effectively avoid the problem of poor dispersion of inorganic flame retardants in the organic system, and at the same time can assist the antistatic masterbatch to jointly improve the antistatic performance of the product.

[0018] Further, the particle size of the calcium carbonate is 1 μm - 4 μm.

[0019] By adopting the above technical solution, the particle size of calcium carbonate is strictly controlled to ensure good dispersion of calcium carbonate in the system, which is beneficial to the excellent air permeability of the breathable film after stretching.

[0020] Further, the antistatic agent is prepared through the following steps: uniformly disperse zinc oxide and polyetherimide in a silane coupling agent and a calcium source solution to form a slurry, add a carbonate solution to the slurry while stirring to obtain a solid product, filter and dry the solid product to obtain the antistatic agent.

[0021] Further, the component dosage of the antistatic agent is as follows: by weight, 1 - 5 parts of zinc oxide, 1 - 3 parts of polyetherimide, 0.1 - 0.5 parts of silane coupling agent, 10 - 20 parts of calcium source solution, and 12 - 22 parts of carbonate.

[0022] Furthermore, the calcium source solution is calcium acetate solution or calcium nitrate solution, and the carbonate solution is sodium carbonate solution. Both calcium acetate solution and calcium nitrate solution can provide calcium ions, and sodium carbonate solution provides carbonate ions, which is beneficial to the combination of the two to form calcium carbonate precipitation.

[0023] Further, the calcium source solution is preferably calcium acetate solution. The sodium acetate formed by the reaction of calcium acetate solution and sodium carbonate solution can play a role in thickening, lubricating, and bonding to a certain extent, which can improve the ductility and processing performance of plastic products, thereby improving the mechanical properties of the product. At the same time, it can also endow the product with a certain anti-corrosion and antibacterial effect, assisting the antibacterial masterbatch to improve the antibacterial performance of the product.

[0024] First, zinc oxide and polyetherimide are uniformly dispersed in a silane coupling agent and a calcium source solution. The silane coupling agent can effectively improve the compatibility between the raw material components and enhance their uniformity. Subsequently, the carbonate ions in the added carbonate solution combine with the calcium ions in the calcium source solution, and during the stirring process, they entrap zinc oxide and polyetherimide to form calcium carbonate precipitation. The obtained antistatic agent not only has excellent antistatic properties but also can be used as a filler to reinforce the product in combination with the antistatic masterbatch. At the same time, it promotes the uniform dispersion between the components, improves the compounding between the components, and enhances the mechanical properties of the product. Zinc oxide not only has good antistatic properties but also has a certain antibacterial effect, which can further cooperate with the antibacterial masterbatch to achieve an excellent antibacterial effect. Polyetherimide also has a certain flame retardancy and can cooperate with the flame retardant masterbatch to improve the flame retardant performance of the product.

[0025] Further, the bacteriostatic agent includes tea polyphenols and / or clove essential oil.

[0026] Furthermore, tea polyphenols and clove essential oil are compounded in a weight ratio of 1:(0.5 - 1).

[0027] By adopting the above technical solution, both tea polyphenols and clove essential oil can achieve good antibacterial effects. After compounding tea polyphenols and clove essential oil, it can effectively improve the inhibitory effect of the product on Escherichia coli and Staphylococcus aureus, achieving an excellent antibacterial effect.

[0028] In a second aspect, the present application provides a preparation method for a multifunctional polyethylene breathable film, adopting the following technical solution: A preparation method for a multifunctional polyethylene breathable film includes the following steps: Mix, melt-extrude, blow-mold, draw, stretch into a film, and corona treat linear low-density polyethylene, metallocene linear low-density polyethylene, low-density polyethylene, a breathable masterbatch, an antistatic masterbatch, an antibacterial masterbatch, a flame retardant masterbatch, and a color masterbatch according to the formulated amounts.

[0029] Further, after the raw material components are mixed, they are extrusion-melted through three-layer coextrusion and then extruded from a die head, that is, they are melted by three screws and then fused at the die head and extruded through one die head. The die head temperature is 175 - 185 °C, and the extrusion rate is 560 - 600 kg / h;

[0030] Further, the drawing speed is 25 m / min, and the drawing ratio is 4.4 - 4.6.

[0031] Further, preparation of the breathable masterbatch: Extrude and pelletize each raw material component according to the formula amount to obtain a breathable masterbatch with a melt index of 1-2 g / 10 min; Further, preparation of the antistatic masterbatch: Extrude and pelletize each raw material component according to the formula amount to obtain an antistatic masterbatch with a melt index of 10-20 g / 10 min; Further, preparation of the antibacterial masterbatch: Extrude and pelletize each raw material component according to the formula amount to obtain an antibacterial masterbatch with a melt index of 1-8 g / 10 min; Further, preparation of the flame retardant masterbatch: Extrude and pelletize each raw material component according to the formula amount to obtain a flame retardant masterbatch with a melt index of 2-10 g / 10 min; By adopting the above technical solutions: Through the raw material component ratio and combined with three-layer coextrusion, the improvement of the microporous path is realized, so that the breathable membrane has dense and interconnected micropores. Combined with the traction and stretching steps, the breathable membrane not only has excellent air permeability and mechanical properties, but also has excellent antistatic, flame retardant and antibacterial functions, and can meet the different functional requirements of users for the breathable membrane.

[0032] In summary, the present application has the following beneficial effects: 1. The selection of linear low-density polyethylene, metallocene linear low-density polyethylene, and low-density polyethylene for compounding, combined with the breathable masterbatch, not only makes the product more breathable, but also makes the air permeability of the product more uniform. Combined with the antistatic masterbatch, it can effectively reduce the surface resistance of the product, endow the product with excellent antistatic performance, and at the same time cooperate with the flame retardant masterbatch to effectively improve the flame retardant performance of the product. Under the action of the antibacterial masterbatch, it has excellent antibacterial performance against Escherichia coli and Staphylococcus aureus, meeting the different functional requirements of users for the breathable membrane.

[0033] 2. Zinc oxide and polyetherimide are uniformly dispersed in the silane coupling agent and calcium source solution. The silane coupling agent can effectively improve the compatibility between each raw material component and improve its uniformity. Subsequently, the carbonate ions in the added carbonate solution combine with the calcium ions in the calcium source solution, and the zinc oxide and polyetherimide are wrapped and calcium carbonate precipitation is formed during the stirring process; The obtained antistatic agent not only has excellent antistatic effect, but also can be used as a filler to reinforce the product in combination with the antistatic masterbatch, while promoting the uniform dispersion between each component, improving the compounding between components, and improving the mechanical properties of the product. Zinc oxide not only has a good antistatic effect, but also has a certain antibacterial effect, which can further cooperate with the antibacterial masterbatch to achieve an excellent antibacterial effect. Polyetherimide also has a certain flame retardancy, which can cooperate with the flame retardant masterbatch to improve the flame retardant performance of the product.

[0034] 3. By adjusting the raw material composition ratio and combining with three - layer co - extrusion, the improvement of the microporous path is achieved, enabling the breathable membrane to have dense and interconnected micropores. Combining with the drawing and stretching steps, the breathable membrane not only has excellent air permeability and mechanical properties, but also has excellent antistatic, flame - retardant and antibacterial functions, meeting the different functional requirements of users for the breathable membrane. Brief Description of the Drawings

[0035] Figure 1 It is a micrograph of the breathable membrane prepared in Example 6 of this application under a scanning electron microscope at 10 μm.

[0036] Figure 2 It is a micrograph of the breathable membrane prepared in Example 6 of this application under a scanning electron microscope at 2 μm. Detailed Embodiments

[0037] The following will describe the implementation schemes of the present invention in detail in combination with examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. The specific conditions not specified in the examples are carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0038] Examples

[0039] Example 1

[0040] A multifunctional polyethylene breathable membrane, comprising raw materials in the following weight percentages: linear low - density polyethylene 22%, metallocene linear low - density polyethylene 15%, low - density polyethylene 7%, breathable masterbatch 38%, antistatic masterbatch 7%, antibacterial masterbatch 5%, flame - retardant masterbatch 3%, color masterbatch 3%;

[0041] Among them, the breathable masterbatch comprises raw materials in the following weight percentages: linear low - density polyethylene 20%, metallocene linear low - density polyethylene 20%, low - density polyethylene 15%, calcium carbonate 42.5%, antioxidant 1.2%, lubricant 0.3%, anti - yellowing agent 1%; the antibacterial masterbatch comprises raw materials in the following weight percentages: linear low - density polyethylene 45%, metallocene linear low - density polyethylene 10%, low - density polyethylene 5%, calcium carbonate 28%, antibacterial agent 10%, antioxidant 0.5%, lubricant 0.3%, anti - yellowing agent 1.2%; the antibacterial agent is tea polyphenol;

[0042] The flame retardant masterbatch comprises raw materials in the following weight percentages: linear low density polyethylene 25%, metallocene linear low density polyethylene 20%, low density polyethylene 15%, bismaleimide 36%, antioxidant 1.6%, lubricant 0.4%, anti-yellowing agent 2%. The antistatic masterbatch comprises raw materials in the following weight percentages: linear low density polyethylene 40%, metallocene linear low density polyethylene 10%, low density polyethylene 5%, antistatic agent 41%, antioxidant 2%, lubricant 1%, anti-yellowing agent 1%. The antistatic agent is prepared through the following steps: uniformly dispersing 0.1 kg of zinc oxide and 0.3 kg of polyetherimide in 0.01 kg of silane coupling agent and 1 kg of calcium nitrate solution to form a slurry, adding 1.2 kg of sodium carbonate solution to the slurry while stirring to obtain a solid product, filtering and drying the solid product to obtain the antistatic agent. The particle size of the calcium carbonate used in the breathable masterbatch, antibacterial masterbatch, flame retardant masterbatch and antistatic masterbatch is 1 μm - 4 μm, the antioxidant is antioxidant 1010, the lubricant is zinc stearate, and the anti-yellowing agent is adipic dihydrazide.

[0043] The preparation method of the multifunctional polyethylene breathable film comprises the following steps:

[0044] Preparation of the breathable masterbatch: Mixing each raw material component of the breathable masterbatch according to the formula amount by twin-screw extrusion granulation to obtain a breathable masterbatch with a melt index of 1 - 2 g / 10 min;

[0045] Preparation of the antistatic masterbatch: Mixing each raw material component according to the formula amount by twin-screw extrusion granulation to obtain an antistatic masterbatch with a melt index of 10 - 20 g / 10 min; Preparation of the antibacterial masterbatch: Mixing each raw material component according to the formula amount by twin-screw extrusion granulation to obtain an antibacterial masterbatch with a melt index of 1 - 8 g / 10 min; Preparation of the flame retardant masterbatch: Mixing each raw material component according to the formula amount by twin-screw extrusion granulation to obtain a flame retardant masterbatch with a melt index of 2 - 10 g / 10 min; Feeding the prepared breathable masterbatch, antistatic masterbatch, antibacterial masterbatch, flame retardant masterbatch, linear low density polyethylene, metallocene linear low density polyethylene, low density polyethylene and color masterbatch into a mixer according to the formula amount for mixing, and then

[0046] extruding through three-layer co-extrusion for extrusion melting and then extruding through a die head, that is, melting through three screws and fusing at the die head, and extruding through one die head. The temperature of the die head is 175 - 185 °C, and the extrusion amount is 580 kg / h; Subsequently, blow molding, traction, stretching into a film, and corona treatment are carried out. The traction speed is 25 m / min, and the stretching ratio is 4.4 - 4.6.

[0047] Example 2

[0048] Multifunctional polyethylene breathable film, comprising raw materials in the following weight percentages: linear low density polyethylene 15%, metallocene linear low density polyethylene 20%, low density polyethylene 5%, breathable masterbatch 49%, antistatic masterbatch 2%, antibacterial masterbatch 2%, flame retardant masterbatch 5%, color masterbatch 2%;

[0049] Among them, the breathable masterbatch comprises raw materials in the following weight percentages: linear low density polyethylene 25%, metallocene linear low density polyethylene 10%, low density polyethylene 5%, calcium carbonate 56%, antioxidant 0.5%, lubricant 1%, anti-yellowing agent 2.5%; the antibacterial masterbatch comprises raw materials in the following weight percentages: linear low density polyethylene 15%, metallocene linear low density polyethylene 18%, low density polyethylene 10%, calcium carbonate 50%, antibacterial agent 2%, antioxidant 2%, lubricant 1%, anti-yellowing agent 2%; the antibacterial agent is clove essential oil;

[0050] The flame retardant masterbatch comprises raw materials in the following weight percentages: linear low density polyethylene 25%, metallocene linear low density polyethylene 14%, low density polyethylene 6.5%, bismaleimide 50%, antioxidant 1.4%, lubricant 1%, anti-yellowing agent 2.1%, and the antistatic masterbatch comprises raw materials in the following weight percentages: linear low density polyethylene 40%, metallocene linear low density polyethylene 12%, low density polyethylene 15%, antistatic agent 30%, antioxidant 0.5%, lubricant 0.7%, anti-yellowing agent 1.8%; the antistatic agent is prepared by the following steps: uniformly dispersing 0.5 kg of zinc oxide and 0.1 kg of polyetherimide in 0.05 kg of silane coupling agent and 2 kg of calcium nitrate solution to form a slurry, adding 2.2 kg of sodium carbonate solution to the slurry while stirring to obtain a solid product, filtering and drying the solid product to obtain the antistatic agent; the calcium carbonate used in the breathable masterbatch, antibacterial masterbatch, flame retardant masterbatch and antistatic masterbatch has a particle size of 6 μm - 10 μm, the antioxidant is antioxidant 168, the lubricant is calcium stearate, and the anti-yellowing agent is anti-yellowing agent HN150.

[0051] The preparation method of the multifunctional breathable film is the same as that of Example 1.

[0052] Example 3

[0053] The difference from Example 1 is that the raw materials of linear low density polyethylene, metallocene linear low density polyethylene and low density polyethylene used in the breathable masterbatch, antibacterial masterbatch, flame retardant masterbatch and antistatic masterbatch are all equally replaced with low density polyethylene, and the rest are the same as Example 1.

[0054] Example 4

[0055] The difference from Example 1 is that in the antibacterial masterbatch, the antibacterial agent is tea polyphenol and clove essential oil with a weight ratio of 1:0.5, and the rest are the same as Example 1.

[0056] Example 5

[0057] The difference from Example 1 is that in the antibacterial masterbatch, the antibacterial agent is tea polyphenol and clove essential oil with a weight ratio of 3:1, and the rest are the same as in Example 1.

[0058] Example 6

[0059] The difference from Example 4 is that the antistatic agent is prepared by the following steps: 0.3 kg of zinc oxide and 0.2 kg of polyetherimide are evenly dispersed in 0.04 kg of silane coupling agent and 1.5 kg of calcium nitrate solution to form a slurry. While stirring, 1.6 kg of sodium carbonate solution is added to the slurry to obtain a solid product. The solid product is filtered and dried to obtain the antistatic agent; the rest are the same as in Example 4.

[0060] Example 7

[0061] The difference from Example 4 is that the antistatic agent is prepared by the following steps: 0.6 kg of zinc oxide and 0.05 kg of polyetherimide are evenly dispersed in 0.01 kg of silane coupling agent and 0.6 kg of calcium acetate solution to form a slurry. While stirring, 2.6 kg of sodium carbonate solution is added to the slurry to obtain a solid product. The solid product is filtered and dried to obtain the antistatic agent; the rest are the same as in Example 4.

[0062] Example 8

[0063] The difference from Example 6 is that the preparation method of the multifunctional polyethylene breathable film includes the following steps: The prepared breathable masterbatch, antistatic masterbatch, antibacterial masterbatch, flame retardant masterbatch, linear low density polyethylene, metallocene linear low density polyethylene, low density polyethylene and color masterbatch are fed into a mixer according to the formula amount for mixing, and then melt extrusion is carried out. The temperature of the extrusion head is 175 - 185 °C, and the extrusion amount is 580 kg / h; then blow molding, traction, stretching into a film, and corona treatment are carried out. The traction speed is 20 m / min, and the stretching ratio is 5.5; the rest are the same as in Example 6.

[0064] Comparative Example

[0065] Comparative Example 1

[0066] The difference from Example 6 is that the antistatic masterbatch is obtained by mixing linear low density polyethylene and polyetherimide with a weight ratio of 1:0.4. The dosage of the antistatic masterbatch and the rest of the components are the same as in Example 6.

[0067] Comparative Example 2

[0068] The difference from Example 6 is that the antistatic agent is prepared through the following steps: 0.5 kg of zinc oxide is evenly dispersed in 0.04 kg of silane coupling agent to obtain the antistatic agent; the rest is the same as in Example 6.

[0069] Comparative Example 3

[0070] The difference from Example 6 is that linear low-density polyethylene is used to replace the antistatic masterbatch in equal amount, and the rest is the same as in Example 6.

[0071] Comparative Example 4

[0072] The difference from Example 6 is that in the flame retardant masterbatch, bismaleimide is replaced with whitened red phosphorus flame retardant in equal amount, and the rest is the same as in Example 6.

[0073] Performance detection test

[0074] Use the Wang Yanshi air permeability tester of model EG02-5 / 6-1.2MR to test the air permeability of the breathable films of Examples 1-8 and Comparative Examples 1-4, and record the results in Table 1.

[0075] Use a surface resistance meter to test the surface resistance of the breathable films of Examples 1-8 and Comparative Examples 1-4, conduct a fire rating test according to the American UL94 fire prevention standard, and detect the antibacterial rates against Escherichia coli and Staphylococcus aureus according to GB / T 31402-2015 "Test Method for Antibacterial Properties of Plastics Surfaces". The results are shown in Table 1.

[0076] Conduct maximum tensile force and maximum elongation rate tests on the breathable films of Examples 1-8 and Comparative Examples 1-4 according to ISO1184 "Determination of Tensile Properties of Plastic Films". Among them, the longitudinal maximum tensile force of the breathable films obtained in Examples 1-8 is all greater than 25 N, the transverse maximum tensile force is all greater than 4 N, the longitudinal maximum elongation rate is all greater than 60%, and the transverse maximum elongation rate is all greater than 450%. The results of Example 6 and Comparative Examples 1-4 are shown in Table 2.

[0077] Table 1

[0078]

[0079]

[0080] Table 2

[0081] Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Longitudinal maximum tensile force / N 30.5 20.7 21.4 28.2 27.1 Transverse maximum tensile force / N 5.6 3.2 3.5 4.7 4.6 Longitudinal maximum elongation / % 77.2 60.5 66.3 75.6 70.2 Transverse maximum elongation / % 489.5 443.1 456.8 472.3 465.4

[0082] Combined with Examples 1-8 and in conjunction with Tables 1 and 2, it can be seen that the breathable film prepared by using the raw material ratio and preparation method of the present application not only has good air permeability and mechanical properties, but also has excellent antistatic, flame retardant and antibacterial functions, and can meet the different functional requirements of users for the breathable film.

[0083] Combined with Example 6 and Comparative Examples 1-3 and in conjunction with Tables 1 and 2, it can be seen that the antistatic masterbatch prepared by using the raw material components and preparation method of the present application can not only significantly improve the antistatic performance of the product, but also assist in improving the flame retardant and antibacterial properties of the product, improve the antibacterial effect of the breathable film against Escherichia coli and Staphylococcus aureus, and endow the breathable film with better maximum longitudinal tensile force, maximum transverse tensile force, maximum longitudinal elongation and maximum transverse elongation, and the mechanical properties of the breathable film are good. This is because zinc oxide and polyetherimide are uniformly dispersed in the silane coupling agent and calcium source solution. The silane coupling agent can effectively improve the compatibility between the raw material components and improve their uniformity. Subsequently, the carbonate ions in the carbonate solution combine with the calcium ions in the calcium source solution, and entrap zinc oxide and polyetherimide during the stirring process to form calcium carbonate precipitation; the obtained antistatic agent not only has excellent antistatic effect, but also can be used as a filler to reinforce the product in combination with the antistatic masterbatch, and at the same time promote the uniform dispersion between the components, improve the composite property between the components, and improve the mechanical properties of the product. And zinc oxide not only has good antistatic effect, but also has certain antibacterial effect, which can further cooperate with the antibacterial masterbatch to achieve excellent antibacterial effect. Polyetherimide also has certain flame retardancy, which can cooperate with the flame retardant masterbatch to improve the flame retardant performance of the product.

[0084] Combined with Example 6 and Comparative Example 4 and in conjunction with Table 1, it can be seen that using bismaleimide as a flame retardant can effectively avoid the problem of poor dispersion of inorganic flame retardants in the organic system, and at the same time can assist the antistatic masterbatch to synergistically improve the antistatic performance of the product.

[0085] This specific embodiment is only an explanation of the present application, and it is not a limitation of the present application. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A multifunctional polyethylene breathable film, characterized in that, The raw materials include the following weight percentages: linear low-density polyethylene 15%-30%, metallocene linear low-density polyethylene 15%-20%, low-density polyethylene 5%-10%, breathable masterbatch 30-50%, antistatic masterbatch 2%-10%, antibacterial masterbatch 2-10%, flame retardant masterbatch 5-10%, and color masterbatch 2-5%; The antistatic masterbatch comprises the following raw materials in weight percentage: 55-67% polyethylene, 30-41% antistatic agent, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent; The antistatic agent is prepared by the following steps: uniformly dispersing zinc oxide and polyetherimide in a silane coupling agent and a calcium source solution to form a slurry, adding a carbonate solution to the slurry while stirring to obtain a solid product, filtering and drying the solid product to obtain the antistatic agent; The flame retardant masterbatch comprises the following raw materials in percentage by weight: 40-80% polyethylene, 15-50% bismaleimide, 0.5-2% antioxidant, 0.3-1% lubricant, and 1-2.5% anti-yellowing agent.

2. The multifunctional polyethylene breathable membrane according to claim 1, characterized in that: The breathable masterbatch comprises the following raw materials in percentage by weight: 40-55% polyethylene, 40-56% calcium carbonate, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent.

3. The multifunctional polyethylene breathable membrane according to claim 1, characterized in that: The antibacterial masterbatch comprises the following raw materials in percentage by weight: 40-60% polyethylene, 28-50% calcium carbonate, 2-10% antibacterial agent, 0.5%-2% antioxidant, 0.3-1% lubricant, and 1%-2.5% anti-yellowing agent.

4. The multifunctional polyethylene breathable membrane according to any one of claims 2 to 3, characterized in that: The particle size of the calcium carbonate is 1 μm-4 μm.

5. The multifunctional polyethylene breathable film according to claim 3, characterized in that: The antibacterial agent includes tea polyphenols and / or clove essential oil.

6. The preparation method of the multifunctional polyethylene breathable film according to any one of claims 1-5, characterized in that: The following steps are involved: According to the formula, linear low density polyethylene, metallocene linear low density polyethylene, low density polyethylene, breathable masterbatch, antistatic masterbatch, antibacterial masterbatch, flame retardant masterbatch and color masterbatch are mixed, melt extruded, blown, pulled, stretched into film and corona treated.

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