Antibacterial toughened polyethylene film and preparation method thereof

Abstract

The present application discloses an antibacterial toughened polyethylene film and a preparation method thereof. The antibacterial toughened polyethylene film comprises the following components by weight: 45 to 50 parts of high-density polyethylene particles, 15 to 20 parts of low-density polyethylene particles, 0.5 to 0.75 parts of antioxidants, and 6 to 8 parts of antibacterial toughened particles; the antibacterial toughened particles are hydrotalcite particles prepared by metal oxide sol intercalation; the preparation method comprises: firstly mixing low-density polyethylene particles, antioxidants and antibacterial toughened particles according to the formula, and collecting the mixture; S2, extruding the mixture into granules and collecting the extruded particles; S3, then mixing the extruded particles with high-density polyethylene particles, extruding and blowing the film, and rolling up to prepare the antibacterial toughened polyethylene film. The antibacterial toughened polyethylene film of the present application can be used for fresh-keeping packaging, and it has excellent antibacterial properties and mechanical strength, and improves the mechanical strength of the polyethylene film fresh-keeping packaging material.

Description

Technical Field

[0001] The present application relates to the field of polyethylene films, and more specifically, to an antibacterial toughened polyethylene film and a preparation method thereof. Background Art

[0002] The principle of antimicrobial packaging is to add antimicrobial agents to packaging materials so that the packaging materials have the function of inhibiting or slowing down the growth of microorganisms, thereby maintaining the quality of packaged food and extending the shelf life. Polyethylene is a high molecular polymer formed by the polymerization of ethylene monomers. It is the most widely used variety of synthetic resins and is mainly used to make films, daily necessities, etc. Therefore, polyethylene film is also widely used in various packaging materials.

[0003] In the related art, a Chinese patent with publication number CN108997634A discloses a method for preparing a degradable antibacterial polyethylene film, the steps of which are as follows: (1) taking equal masses of TiO and NiCoMnO powders, polyethylene wax and polyethylene powders, and mixing them thoroughly with an internal mixer until the torque drops steadily; (2) adding a dispersant to the uniformly mixed material at a temperature of 290 to 400°C to melt it, introducing nitrogen gas to carry out a condensation reaction under high temperature conditions for 5 to 8 hours, and then extruding it through a twin-screw mixer, air cooling and granulation to prepare composite masterbatch particles filled with TiO and NiCoMnO; (3) mixing the masterbatch particles and polyethylene evenly in a high-speed disperser, and blowing the film through a film blowing unit to obtain a composite film. This scheme uses two catalysts with different energy band structures. During the migration, most of the electrons and holes are blocked by polyethylene molecules and react with polyethylene, resulting in polyethylene degradation. The application is not limited by light source conditions, and nano-TiO has a sterilization effect on different bacteria.

[0004] With respect to the above-mentioned related technologies, the inventors believe that in the technical solution of improving the antibacterial properties of polyethylene film materials by adding antibacterial materials to polyethylene films, the additives will affect the physical and mechanical properties of the packaging materials, reduce the continuity of the non-crystalline structural regions of the polyethylene materials, and thus reduce the toughness strength and mechanical properties of the polyethylene film materials. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0006] In view of this, the present invention provides an antibacterial toughened polyethylene film, which has excellent antibacterial properties and excellent toughness strength.

[0007] The present invention also provides a method for preparing an antibacterial toughened polyethylene film. The preparation method is simple, and the additive material prepared by the method has excellent toughness performance and high mechanical strength.

[0008] The antibacterial toughened polyethylene film according to the first embodiment of the present invention comprises the following components in parts by weight: 45 to 50 parts of high-density polyethylene particles, 15 to 20 parts of low-density polyethylene particles, 0.5 to 0.75 parts of antioxidants, and 6 to 8 parts of antibacterial toughening particles; the antibacterial toughening particles are hydrotalcite particles prepared by metal oxide sol intercalation.

[0009] According to the antibacterial toughened polyethylene film of the embodiment of the present invention, metal oxide sol is intercalated inside the hydrotalcite particles. On the one hand, after the metal oxide sol is intercalated into the hydrotalcite, the metal ions carried by the metal oxide sol can effectively inhibit the growth of bacteria and improve the antibacterial properties of the polyethylene film material, thereby achieving good antibacterial effect; secondly, the present application uses the hydrotalcite intercalated with the metal oxide sol as an inorganic filler to fill the inside of the polyethylene film, thereby improving the structural strength and toughness properties of the polyethylene film material; at the same time, the surface of the hydrotalcite material after metal intercalation is effectively coated with active groups, thereby improving the soft agglomeration of the hydrotalcite under hydrogen bonding, and reducing the hard agglomeration produced by the condensation of hydroxyl groups on the surface of the active groups, so that the hydrotalcite matrix is ​​effectively dispersed inside the polyethylene film, thereby effectively taking into account good toughness strength and antibacterial properties.

[0010] The antibacterial toughened polyethylene film according to the embodiment of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, the antibacterial toughening particles are prepared by the following scheme: (1) zinc nitrate and aluminum nitrate are stirred and mixed at a Zn:Al molar ratio of 3:1, the mixed particles are collected and added to deionized water, the solution concentration is adjusted to 0.3 mol / L to obtain a solution, a metal oxide sol of equal molar mass to the aluminum nitrate is taken, the solution is stirred and mixed with the metal oxide sol to obtain a matrix liquid;

[0012] (2) The pH of the base liquid is adjusted to 8.5, and then the mixture is stirred at 35-55° C. for 24 hours, filtered and the filter cake is collected, and dried at 75-85° C. for 6-8 hours to prepare the antibacterial toughened particles.

[0013] According to one embodiment of the present invention, step (2) also includes: alkali etching treatment, and the specific steps of the alkali etching treatment include: adding the antibacterial toughening particles to a sodium hydroxide solution, stirring and mixing and standing for 15 to 20 hours, then centrifuging at 2500 to 3000 r / min for 10 to 15 minutes, washing and drying, and preparing alkali-etched antibacterial toughening particles.

[0014] According to one embodiment of the present invention, the concentration of the sodium hydroxide solution is 0.85-1.25 mol / L.

[0015] According to one embodiment of the present invention, the metal oxide sol includes one or more of zinc oxide sol, copper oxide sol and titanium oxide sol.

[0016] According to one embodiment of the present invention, the particle size of the metal oxide sol is not greater than 100 nm.

[0017] The method for preparing an antibacterial toughened polyethylene film according to the second aspect of the present invention comprises the following steps:

[0018] S1. According to the formula, low-density polyethylene particles, antioxidants and antibacterial toughening particles are placed in a high-speed stirring device for stirring and mixing, and the mixture is collected;

[0019] S2, placing the mixed material in a twin-screw extruder, adjusting the temperatures of zones 1 to 7 of the twin-screw extruder to 140° C., 170° C., 170° C., 170° C., 170° C., 170° C. and 160° C. in sequence, extruding and granulating at a rotation speed of 55 r / min and collecting the extruded particles;

[0020] S3. Stir and mix the extruded particles with high-density polyethylene particles and place them in a film blowing machine, adjust the temperatures of the first, second and third zones of the film blowing machine to 165°C, 180°C and 180°C respectively, and the temperature of the extrusion die of the film blowing machine is 165°C. Extrusion, blowing and winding can produce the antibacterial toughened polyethylene film.

[0021] According to one embodiment of the present invention, the pulling rate of the extrusion blown film is 350 m / min.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below. The embodiments are exemplary and are only used to explain the present invention, but are not to be construed as limiting the present invention.

[0024] The antibacterial toughened polyethylene film and the preparation method thereof according to the embodiments of the present invention are described in detail below.

[0025] First, the antibacterial toughened polyethylene film according to the embodiment of the present invention is mainly composed of the following substances in parts by weight: 45 to 50 parts of high-density polyethylene particles, 15 to 20 parts of low-density polyethylene particles, 0.5 to 0.75 parts of antioxidants, and 6 to 8 parts of antibacterial toughening particles; the antibacterial toughening particles are hydrotalcite particles prepared by metal oxide sol intercalation.

[0026] Therefore, according to the antibacterial toughened polyethylene film of the embodiment of the present invention, metal oxide sol is intercalated inside the hydrotalcite particles. On the one hand, after the metal oxide sol is intercalated into the hydrotalcite, the metal ions carried by the metal oxide sol can effectively inhibit the growth of bacteria and improve the antibacterial properties of the polyethylene film material, thereby achieving good antibacterial effect. Secondly, the present application uses the hydrotalcite intercalated with the metal oxide sol as an inorganic filler to fill the polyethylene film, thereby improving the structural strength and toughness of the polyethylene material. At the same time, the active groups on the surface of the hydrotalcite material after the metal intercalation are effectively coated, thereby improving the soft agglomeration of the hydrotalcite under hydrogen bonding, and reducing the hard agglomeration produced by the condensation of the surface hydroxyl groups of the active groups, so that the hydrotalcite matrix is ​​effectively dispersed inside the polyethylene film, thereby effectively taking into account good toughness strength and antibacterial properties.

[0027] According to one embodiment of the present invention, the antibacterial toughened particles are prepared by the following scheme: (1) zinc nitrate and aluminum nitrate are stirred and mixed at a Zn:Al molar ratio of 3:1, the mixed particles are collected and added to deionized water, the solution concentration is adjusted to 0.3 mol / L to obtain a solution, a metal oxide sol of equal molar mass to the aluminum nitrate is taken, the solution and the metal oxide sol are stirred and mixed to obtain a matrix liquid; (2) the pH of the matrix liquid is adjusted to 8.5, and then the mixture is stirred at 35-55°C for 24 hours, the filter cake is filtered and collected, and the filter cake is dried at 75-85°C for 6-8 hours to prepare the antibacterial toughened particles.

[0028] By adopting the above technical scheme, since metal oxide sol is intercalated into the hydrotalcite during its preparation, on the one hand, the hydrotalcite is a type of layered double metal hydroxide composed of a main layer plate with a positive charge and exchangeable anions between layers, and has nano-sized interlayer gaps in its structure, which can effectively load the metal oxide sol; on the other hand, the hydrotalcite filled with the intercalated metal oxide sol has a good dispersed structure, thereby further improving the structural uniformity of the antibacterial polyethylene film material, thereby improving the toughness strength and mechanical properties of the polyethylene film material.

[0029] In some specific embodiments of the present invention, the antibacterial toughened particle preparation step (2) also includes alkaline etching treatment, and the specific steps of the alkaline etching treatment include: adding the antibacterial toughened particles to a sodium hydroxide solution, stirring and mixing and standing for 15 to 20 hours, then centrifuging at 2500 to 3000 r / min for 10 to 15 minutes, washing and drying, and preparing alkaline-etched antibacterial toughened particles.

[0030] By adopting the above technical solution, since the present application performs alkaline etching on the hydrotalcite matrix, the purpose is that the alkaline etching treatment can form a multi-porous corrosion structure on the surface of the antibacterial toughening particles to a certain extent, thereby improving the specific surface area of ​​the antibacterial toughening particles and improving the structural performance of the antibacterial toughening particles. At the same time, in the technical solution of the present application, the antibacterial toughening particles are subjected to alkaline etching treatment to reduce the bonding strength between the surface active groups, thereby further improving their dispersion performance, improving the structural uniformity of the antibacterial polyethylene film material, and improving the toughness strength and mechanical properties of the polyethylene film material.

[0031] Furthermore, the concentration of the sodium hydroxide solution is 0.85-1.25 mol / L.

[0032] By adopting the above-mentioned technical scheme, since the technical scheme of the present application optimizes the concentration of the sodium hydroxide solution, it prevents the concentration of the alkaline etching from being too low to form an etching effect on the antibacterial toughening particles. On the other hand, it also prevents the concentration of the alkaline etching solution from being too high, resulting in more serious corrosion of the antibacterial toughening particles, thereby destroying the strength of the antibacterial toughening particles.

[0033] In some specific embodiments of the present invention, the metal oxide sol includes a mixture of one or more of zinc oxide sol, copper oxide sol and titanium oxide sol.

[0034] By adopting the above-mentioned technical scheme, since the present application optimizes the composition of the metal oxide sol, since copper oxide has good antibacterial and antifungal effects, titanium oxide and zinc oxide particles have good photocatalytic degradation properties, and bacteria are effectively inhibited and treated by metal ions, the antibacterial effect of the antibacterial toughened particles of the technical scheme of the present application can be effectively improved.

[0035] Furthermore, the particle size of the metal oxide sol is not greater than 100 nm.

[0036] By adopting the above technical scheme, since the present application optimizes the particle size of the metal oxide, the optimized metal oxide can be effectively intercalated into the interior of the hydrotalcite, thereby forming a good load and filling. At the same time, the metal oxide of this particle size can be effectively filled into the interior of the hydrotalcite structure, thereby forming a stable load, further improving the antibacterial effect of the antibacterial toughened particles of the technical scheme of the present application.

[0037] In the second aspect, the present application provides a method for preparing an antibacterial toughened polyethylene film, and the preparation steps of the antibacterial toughened polyethylene film include: S1, placing low-density polyethylene particles, antioxidants and antibacterial toughening particles in a high-speed stirring device according to the formula, stirring and mixing, and collecting the mixture; S2, placing the mixture in a twin-screw extruder, adjusting the temperatures of zones 1 to 7 of the twin-screw extruder to 140°C, 170°C, 170°C, 170°C, 170°C, 170°C, and 160°C, respectively, extruding and granulating at a speed of 55r / min and collecting the extruded particles; S3, then stirring and mixing the extruded particles with high-density polyethylene particles and placing them in a film blowing machine, adjusting the temperatures of zones 1, 2 and 3 of the film blowing machine to 165°C, 180°C and 180°C, respectively, and the temperature of the extrusion die head to 165°C, extruding, blowing and winding to prepare the antibacterial toughened polyethylene film.

[0038] By adopting the above-mentioned technical scheme, the present application disperses the antibacterial toughening particles into a low-density polyethylene material first, performs a pre-dispersion treatment, reduces the agglomeration of inorganic particles in the high-density polyethylene material, and improves the dispersion performance of the antibacterial toughening particles in the high-density polyethylene material through subsequent dispersion treatment, thereby effectively improving the toughness strength and mechanical properties of the polyethylene film material. At the same time, the technical scheme of the present application has simple preparation steps and high preparation efficiency.

[0039] In the technical solution of the present application, the pulling rate of the extrusion blown film is 350 m / min.

[0040] By adopting the above technical solution, the present application limits the pulling rate, and improves the vertical tensile strength of the blown film by optimizing the pulling rate of the blown film, thereby improving the mechanical strength and mechanical properties of the polyethylene film material.

[0041] In summary, this application has the following beneficial effects:

[0042] First, the present application intercalates metal oxide sol inside the hydrotalcite particles. On the one hand, after the metal oxide sol is intercalated into the hydrotalcite, the metal ions carried by it can effectively inhibit the growth of bacteria and improve the antibacterial properties of the polyethylene film material, thereby achieving a good antibacterial effect. Secondly, the present application uses the hydrotalcite intercalated with the metal oxide sol as an inorganic filler to fill the polyethylene film, thereby improving the structural strength and toughness of the polyethylene material. At the same time, the active groups on the surface of the hydrotalcite material after the metal intercalation are effectively coated, thereby improving the soft agglomeration of the hydrotalcite under hydrogen bonding and reducing the hard agglomeration caused by the condensation of the surface hydroxyl groups of the active groups, so that the hydrotalcite matrix is ​​effectively dispersed inside the polyethylene film, thereby effectively taking into account good toughness strength and antibacterial properties.

[0043] Second, the present application performs alkaline etching on the hydrotalcite matrix, the purpose of which is that the alkaline etching treatment can form a multi-porous corrosion structure on the surface of the antibacterial toughening particles to a certain extent, thereby improving the specific surface area of ​​the antibacterial toughening particles and improving the structural properties of the antibacterial toughening particles. At the same time, in the technical scheme of the present application, the alkaline etching treatment of the antibacterial toughening particles is used to reduce the bonding strength between the surface active groups thereof, thereby further improving their dispersion properties, improving the structural uniformity of the antibacterial polyethylene film material, and improving the toughness strength and mechanical properties of the polyethylene film material.

[0044] Third, the present application disperses the antibacterial toughening particles into a low-density polyethylene material for pre-dispersion treatment to reduce the agglomeration of inorganic particles in the high-density polyethylene material. Through subsequent dispersion treatment, the dispersion performance of the antibacterial toughening particles in the high-density polyethylene material is improved, thereby effectively improving the toughness strength and mechanical properties of the polyethylene film material. At the same time, the technical solution of the present application has simple preparation steps and high preparation efficiency.

[0045] Fourth, the present application optimizes the rate of immersion and pulling, optimizes the load and filling efficiency of the sol on the substrate surface, prevents the coating thickness from being too thick, resulting in poor load performance, thereby reducing the adhesion of the coating, and also effectively prevents the coating thickness from being too thin, resulting in poor mechanical strength of the coating material and inability to form good scratch resistance, thereby further improving the mechanical strength and scratch resistance of the coating.

[0046] The antibacterial toughened polyethylene film and the preparation method thereof according to the embodiment of the present invention are described in detail below in conjunction with specific embodiments.

[0047] In the examples of the present application, the raw materials and instruments used are as follows, but not limited thereto:

[0048] All raw materials and instruments in this application can be obtained commercially, and the specific models are as follows:

[0049] Constant temperature magnetic heating stirrer CL-3;

[0050] Electric heating blast drying oven 101-1.

[0051] Preparation Example

[0052] Preparation of alkali-treated antibacterial toughened particles

[0053] Preparation Example 1

[0054] Zinc nitrate and aluminum nitrate were stirred and mixed at a Zn:Al molar ratio of 3:1, the mixed particles were collected and added to deionized water, the solution concentration was adjusted to 0.3 mol / L, a metal oxide sol of equal molar mass to the aluminum nitrate was taken, the solution was stirred and mixed with a metal oxide sol with a particle size of 20 nm to obtain a base liquid, the pH of the base liquid was adjusted to 8.5, and then the mixture was kept warm and stirred at 35°C for 24 hours, filtered and the filter cake was collected, and dried at 75°C for 6 hours to prepare antibacterial toughened particles; the antibacterial toughened particles were added to a 0.85 mol / L sodium hydroxide solution, stirred and mixed and allowed to stand for 15 hours, and then centrifuged at 2500 r / min for 10 minutes, the lower precipitate was removed and rinsed with deionized water 3 times, and then vacuum freeze-dried to prepare alkali-treated antibacterial toughened particles 1.

[0055] Preparation Example 2

[0056] Zinc nitrate and aluminum nitrate were stirred and mixed at a Zn:Al molar ratio of 3:1, the mixed particles were collected and added to deionized water, the solution concentration was adjusted to 0.3 mol / L, a metal oxide sol of equal molar mass to the aluminum nitrate was taken, the solution was stirred and mixed with a metal oxide sol with a particle size of 20 nm to obtain a base liquid, the pH of the base liquid was adjusted to 8.5, and then the mixture was kept warm and stirred at 45°C for 24 hours, filtered and the filter cake was collected, and dried at 80°C for 7 hours to prepare antibacterial toughened particles; the antibacterial toughened particles were added to a 1 mol / L sodium hydroxide solution, stirred and mixed and allowed to stand for 17 hours, and then centrifuged at 2750 r / min for 12 minutes, the lower precipitate was removed and rinsed with deionized water 4 times, and then vacuum freeze-dried to prepare alkali-treated antibacterial toughened particles 2.

[0057] Preparation Example 3

[0058] Zinc nitrate and aluminum nitrate were stirred and mixed at a Zn:Al molar ratio of 3:1, the mixed particles were collected and added to deionized water, the solution concentration was adjusted to 0.3 mol / L, a metal oxide sol of equal molar mass to the aluminum nitrate was taken, the solution was stirred and mixed with a metal oxide sol with a particle size of 20 nm to obtain a base liquid, the pH of the base liquid was adjusted to 8.5, and then the mixture was kept warm and stirred at 55°C for 24 hours, filtered and the filter cake was collected, and dried at 85°C for 8 hours to prepare antibacterial toughened particles; the antibacterial toughened particles were added to a 1.25 mol / L sodium hydroxide solution, stirred and mixed and allowed to stand for 20 hours, and then centrifuged at 3000 r / min for 15 minutes, the lower precipitate was removed and rinsed with deionized water 5 times, and then vacuum freeze-dried to prepare alkali-treated antibacterial toughened particles 3.

[0059] Example

[0060] Example 1

[0061] S1, firstly place 15kg of low-density polyethylene particles, 0.5kg of antioxidant and 6kg of antibacterial toughening particles 1 in a high-speed stirring device and stir and mix, and collect the mixture;

[0062] S2. Place the mixed material in a twin-screw extruder, adjust the temperatures of zones 1 to 7 of the extruder to 140°C, 170°C, 170°C, 170°C, 170°C, 170°C, and 160°C, extrude and granulate at a speed of 55 r / min, and collect the extruded particles;

[0063] S3. Stir and mix the extruded granules with 45 kg of high-density polyethylene granules and place them in a film blowing machine. Adjust the temperatures of the first, second and third zones of the film blowing machine to 165°C, 180°C and 180°C respectively, the extrusion die temperature to 165°C, the traction rate to 350 m / min, extrude the film, blow it and wind it up to obtain the antibacterial toughened polyethylene film.

[0064] Embodiments 2 to 5

[0065] Examples 2 to 5: An antibacterial toughened polyethylene film. The difference from Example 1 is that the antibacterial toughened polyethylene film ratio and preparation parameters are shown in Table 1, and the remaining preparation steps and preparation environment are the same as those of Example 1.

[0066] Table 1 Distribution ratio of each raw material component in Examples 1 to 5

[0067]

[0068] Example 6: An antibacterial toughened polyethylene film, which is different from Example 1 in that the particle size of the metal oxide sol in Example 6 is 70 nm.

[0069] Example 7: An antibacterial toughened polyethylene film, which is different from Example 1 in that the particle size of the metal oxide sol in Example 7 is 100 nm.

[0070] Comparative Example

[0071] Comparative Example 1: An antibacterial toughened polyethylene film. The difference from Example 1 is that Comparative Example 1 uses hydrotalcite particles that are not prepared by metal oxide sol intercalation to replace the alkali-etched antibacterial toughened particles in Example 1, and the other preparation conditions and component ratios are the same as those in Example 1.

[0072] Comparative Example 2: An antibacterial toughened polyethylene film. The difference from Example 1 is that Comparative Example 2 uses hydrotalcite particles prepared by silica sol intercalation to replace the alkali-etched antibacterial toughened particles in Example 1, and the other preparation conditions and component ratios are the same as those in Example 1.

[0073] Comparative Example 3: An antibacterial toughened polyethylene film. The difference from Example 1 is that no alkali-etched antibacterial toughening particles are added in Comparative Example 3, and the other preparation conditions and component ratios are the same as those in Example 1.

[0074] Comparative Example 4: An antibacterial toughened polyethylene film. The difference from Example 1 is that Comparative Example 4 uses a metal oxide sol with a particle size of 200 nm to replace the metal oxide sol in Example 1, and the other preparation conditions and component ratios are the same as those in Example 1.

[0075] Comparative Example 5: An antibacterial toughened polyethylene film. The difference from Example 1 is that Comparative Example 5 uses a metal oxide sol with a particle size of 500 nm to replace the metal oxide sol in Example 1, and the other preparation conditions and component ratios are the same as those in Example 1.

[0076] Comparative Example 6: An antibacterial toughened polyethylene film. The difference from Example 1 is that Comparative Example 5 adopts a traction rate of 500 m / min, and the other preparation conditions and component ratios are the same as those of Example 1.

[0077] Comparative Example 7: An antibacterial toughened polyethylene film. The difference from Example 1 is that Comparative Example 5 adopts a traction rate of 200 m / min, and the other preparation conditions and component ratios are the same as those of Example 1.

[0078] Comparative Example

[0079] Comparative Example 1

[0080] An antibacterial toughened polyethylene film is disclosed. The difference from Example 1 is that the antibacterial toughened particles not alkali-etched in Comparative Example 1 are used to replace the alkali-etched antibacterial toughened particles in Example 1, and the other preparation conditions and component ratios are the same as those in Example 1.

[0081] Performance testing

[0082] The antibacterial properties and toughness strength of the polyethylene films prepared in Examples 1 to 7, Comparative Examples 1 to 7 and Comparative Example 1 were tested respectively.

[0083] Detection method / test method

[0084] (1) Prepare the test samples according to the method in GB / T1040.3-2006. According to the test requirements in ASTM D882-09, set the clamp distance to 50 mm and the tensile rate to 50 mm / min, test the samples, measure each group of samples 10 times, and record the elongation at break and tensile elastic modulus.

[0085] (2) The inhibitory activity of different polyethylene films against Escherichia coli and Staphylococcus aureus was studied using the film sticking method in GB / T 21510-2008. The specific test results are shown in Table 2 below:

[0086] Table 2 Antibacterial toughened polyethylene film performance test table

[0087]

[0088] Performance analysis is performed based on Table 2 above:

[0089] (1) From the composition ratios of each component in Examples 1 to 7 and Table 2, it can be found that the antibacterial toughened polyethylene film prepared in the present application has good mechanical strength and antibacterial properties. This shows that the technical solution of the present application intercalates metal oxide sols inside the hydrotalcite particles, and the metal ions carried can effectively inhibit the growth of bacteria, thereby improving the antibacterial properties of the polyethylene film material, thereby achieving good antibacterial effect. Secondly, the hydrotalcite intercalated with the metal oxide sol is filled into the polyethylene film as an inorganic filler to improve the structural strength and toughness of the polyethylene material. At the same time, the active groups on the surface of the hydrotalcite material after metal intercalation are effectively coated, thereby improving the soft agglomeration of the hydrotalcite under hydrogen bonding, and reducing the hard agglomeration caused by the condensation of the surface hydroxyl groups of the active groups, so that the hydrotalcite matrix is ​​effectively dispersed inside the polyethylene film, thereby effectively taking into account good toughness strength and antibacterial properties.

[0090] (2) The performance of Comparative Examples 1 to 3 was compared with that of Example 1. Since other materials were used in Comparative Examples 1 to 3 to replace the alkaline-etched antibacterial toughening particles in the technical solution of the present application, as shown in Table 2, their mechanical properties and antibacterial properties were significantly reduced. This shows that the technical solution of the present application performs alkaline etching on the hydrotalcite matrix, and its purpose is that the alkaline etching treatment can form a multi-porous corrosion structure on the surface of the antibacterial toughening particles to a certain extent, thereby improving the specific surface area of ​​the antibacterial toughening particles and improving the structural properties of the antibacterial toughening particles. At the same time, in the technical solution of the present application, the alkaline etching treatment of the antibacterial toughening particles is used to reduce the bonding strength between the surface active groups thereof, thereby further improving their dispersion properties, further improving the structural uniformity of the antibacterial polyethylene film material, and thus improving the toughness strength and mechanical properties of the polyethylene film material.

[0091] (3) Comparing Comparative Examples 4 to 5 with Example 1, it can be seen from Table 2 that the mechanical properties and antibacterial properties of Comparative Examples 4 to 5 are significantly reduced after adjusting the particle size of the metal oxide sol. This shows that the technical solution of the present application optimizes the particle size of the metal oxide, and the optimized metal oxide can be effectively intercalated into the interior of the hydrotalcite, thereby forming a good load and filling. At the same time, the metal oxide of this particle size can be effectively filled into the interior of the hydrotalcite structure, thereby forming a stable load, further improving the antibacterial effect of the antibacterial toughening particles of the technical solution of the present application.

[0092] (4) Comparison between Comparative Examples 6 and 7 and Example 1 shows that the pulling rate of the blown film was adjusted when preparing the polyethylene film in Comparative Examples 6 and 7. As shown in Table 2, the mechanical properties were slightly reduced, and the antibacterial properties did not change significantly. This shows that the technical solution of the present application optimizes the pulling rate of the blown film, improves the vertical tensile strength of the blown film, thereby improving the mechanical strength of the film material, thereby further optimizing the mechanical strength and mechanical properties of the polyethylene film material.

[0093] (5) Comparison Example 1 and Example 1 are compared. Comparison Example 1 uses antibacterial toughening particles that have not been alkali-etched to replace the alkali-etched antibacterial toughening particles in Example 1. Combined with the data of Comparison Examples 1 to 3, it can be further explained that the technical scheme of the present application can form a multi-porous corrosion structure on the surface of the antibacterial toughening particles to a certain extent through alkali etching treatment, thereby improving the specific surface area of ​​the antibacterial toughening particles and improving the structural properties of the antibacterial toughening particles. At the same time, in the technical scheme of the present application, the antibacterial toughening particles are subjected to alkali etching treatment to reduce the bonding strength between the surface active groups thereof, thereby further improving their dispersion properties, further improving the structural uniformity of the antibacterial polyethylene film material, and thus improving the toughness strength and mechanical properties of the polyethylene film material.

[0094] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. An antibacterial toughened polyethylene film, characterized in that: By weight, it includes the following components: High-density polyethylene particles, 45-50 parts; Low-density polyethylene particles, 15-20 parts; Antioxidant, 0.5-0.75 parts; Antibacterial toughening particles, 6-8 parts; The antibacterial toughening particles are hydrotalcite particles prepared by metal oxide sol intercalation; The antibacterial toughening particles are prepared by the following scheme: (1) mixing zinc nitrate and aluminum nitrate at a Zn:Al molar ratio of 3:1, collecting the mixed particles and adding them to deionized water, adjusting the solution concentration to 0.3 mol / L to obtain a solution, taking a metal oxide sol of equal molar mass to the aluminum nitrate, mixing the solution with the metal oxide sol, and collecting the matrix liquid; (2) adjusting the pH of the base liquid to 8.5, then keeping it warm and stirring at 35-55° C. for 24 hours, filtering and collecting the filter cake, and drying it at 75-85° C. for 6-8 hours to prepare the antibacterial toughened particles; The metal oxide sol includes one or more of zinc oxide sol, copper oxide sol and titanium oxide sol; The particle size of the metal oxide sol is no greater than 100 nm.

2. The antibacterial toughened polyethylene film according to claim 1, characterized in that: Step (2) also includes: Alkali etching treatment, the specific steps of the alkali etching treatment include: adding the antibacterial toughening particles into a sodium hydroxide solution, stirring and mixing and standing for 15 to 20 hours, then centrifuging at 2500 to 3000 r / min for 10 to 15 minutes, washing and drying, and preparing alkali-etched antibacterial toughening particles.

3. The antibacterial toughened polyethylene film according to claim 2, characterized in that: The concentration of the sodium hydroxide solution is 0.85-1.25 mol / L.

4. A method for preparing an antibacterial toughened polyethylene film according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. According to the formula, low-density polyethylene particles, antioxidants and antibacterial toughening particles are placed in a high-speed stirring device for stirring and mixing, and the mixture is collected; S2, placing the mixed material in a twin-screw extruder, adjusting the temperatures of zones 1 to 7 of the twin-screw extruder to 140° C., 170° C., 170° C., 170° C., 170° C., 170° C. and 160° C. in sequence, extruding and granulating at a rotation speed of 55 r / min and collecting the extruded particles; S3. Stir and mix the extruded particles with high-density polyethylene particles and place them in a film blowing machine, adjust the temperatures of the first, second and third zones of the film blowing machine to 165° C., 180° C. and 180° C. respectively, the temperature of the extrusion die of the film blowing machine is 165° C., extrude, blow film and wind up to prepare the antibacterial toughened polyethylene film.

5. The method for preparing an antibacterial toughened polyethylene film according to claim 4, characterized in that: The pulling speed of the extrusion blown film is 350 m / min.

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