Sterile bag capable of blocking microorganisms and preparation method thereof

Abstract

The invention relates to the technical field of sterile bags, in particular to a sterile bag capable of blocking microorganisms and a preparation method of the sterile bag. The sterile bag capable of blocking the microorganisms is made of a plastic sterile film. The plastic sterile film comprises a surface layer, a middle layer covering one side of the surface layer and a bottom layer covering one side of the middle layer; wherein the raw materials of the surface layer and the bottom layer comprise homo-polypropylene, polylactic acid, grafted silicon dioxide, antibacterial master batches and a lubricant, and the raw materials of the middle layer comprise homo-polypropylene, branched starch, amino-terminated polyamidoamine, an antistatic agent and a lubricant; the grafted silicon dioxide is obtained by reacting activated silicon dioxide with polyvinyl alcohol and triethylene diamine. The degradable plastic film can be naturally degraded, can effectively obstruct microorganisms, and has excellent barrier performance and good mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of sterile bags, and particularly to a sterile bag capable of blocking microorganisms and a preparation method thereof. Background Art

[0002] Sterile bags are essential items in people's daily lives. Commonly used plastic materials include polyethylene, polypropylene, polyvinyl chloride, polystyrene, acrylonitrile-butadiene-styrene copolymer, etc. However, since these commonly used plastic materials often exist stably in nature, they have affected the ecological environment and human health.

[0003] Biodegradation is a chemical process in which available microorganisms in the environment convert biodegradable plastics into natural substances such as water, carbon dioxide, and compost (without artificial additives).

[0004] Currently, polylactic acid, as a completely biodegradable polymer material, has good application and industrialization prospects. However, it also has an obvious drawback, that is, its antibacterial effect is poor, and at the same time, the dispersion of each raw material in the degradable sterile bag is poor. Adding antibacterial agents will seriously affect its mechanical properties. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art, and to provide a sterile bag capable of blocking microorganisms and a preparation method thereof.

[0006] A sterile bag capable of blocking microorganisms is obtained by making a bag with a plastic sterile film. The plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer. The raw materials of the surface layer include, by mass: 50-100 parts of homopolypropylene, 20-40 parts of polylactic acid, 10-20 parts of grafted silica, 5-15 parts of antibacterial masterbatch, and 1-2 parts of lubricant; the raw materials of the intermediate layer include, by mass: 50-100 parts of homopolypropylene, 15-30 parts of branched starch, 1-5 parts of terminal amino polyamide amine, 1-2 parts of antistatic agent, and 1-2 parts of lubricant; the raw materials of the bottom layer include, by mass: 50-100 parts of homopolypropylene, 20-40 parts of polylactic acid, 10-20 parts of grafted silica, 5-15 parts of antibacterial masterbatch, and 1-2 parts of lubricant.

[0007] The above-mentioned grafted silica is prepared by the following steps: adding activated silica to N,N-dimethylformamide, adding polyvinyl alcohol and triethylenediamine, and performing ultrasonic treatment for 1-2 h, stirring at 40-60 °C for 1-2 h, filtering, washing, vacuum drying, and pulverizing.

[0008] Preferably, in the process of preparing grafted silica, the mass ratio of activated silica, polyvinyl alcohol, and triethylenediamine is 10-20:5-10:0.1-1.

[0009] Preferably, during the preparation of grafted silica, the ultrasonic frequency is 20 - 30 kHz.

[0010] Preferably, the activated silica is prepared by the following specific operation: tetraethyl orthosilicate and bamboo charcoal powder are added to an ethanol - aqueous solution and stirred for 10 - 30 min, then hydrochloric acid is added and stirring continues for 1 - 2 h, it is kept warm at 50 - 70 °C for 1 - 2 h, filtered, washed, and vacuum - dried.

[0011] More preferably, the concentration of hydrochloric acid is 1 - 2 mol / L, and the mass ratio of tetraethyl orthosilicate, bamboo charcoal powder, and hydrochloric acid is 5 - 15:10 - 20:1 - 3.

[0012] Preferably, the lubricant is at least one of ethylene bisstearamide, oleic acid amide, and erucic acid amide.

[0013] Preferably, the antibacterial masterbatch is prepared by the following steps: homopolypropylene, an antiblocking agent, an antioxidant, and a double - chain quaternary ammonium salt bacteriostatic agent are mixed evenly, extruded at 180 - 220 °C, and dried.

[0014] More preferably, the mass ratio of homopolypropylene, antiblocking agent, antioxidant, and double - chain quaternary ammonium salt bacteriostatic agent is 10 - 30:1 - 2:1 - 2:1 - 2.

[0015] Preferably, the antiblocking agent is at least one of talc powder, diatomite, kaolin, and calcium carbonate.

[0016] Preferably, the double - chain quaternary ammonium salt bacteriostatic agent includes at least one of didecyldimethylammonium chloride, didecyldimethylammonium bromide, dioctyldimethylammonium chloride, and dioctyldimethylammonium bromide.

[0017] Preferably, the antioxidant includes antioxidant 1076 and antioxidant 626, and the mass ratio of antioxidant 1076 to antioxidant 626 is 1:1 - 2.

[0018] The preparation method of the above - mentioned sterile bag capable of blocking microorganisms includes the following steps: the raw materials of the surface layer, the middle layer, and the bottom layer are respectively mixed evenly, after co - extrusion of the three layers, the obtained melt is attached to a cold drum to form a thick sheet, synchronously biaxially stretched, the stretching temperature is 150 - 165 °C, the stretching ratio is 2 - 4×2 - 4, shaped at 180 - 190 °C for 5 - 15 s, corona - treated after cooling, and made into bags.

[0019] Beneficial effects: In the present invention, taking bamboo charcoal powder as the attachment point, nano - silica is in - situ deposited on it to form activated silica, and then under the catalysis of triethylenediamine, polyvinyl alcohol is grafted on it, greatly improving its interfacial affinity with homopolypropylene and polylactic acid. It not only endows the sterile bag with excellent antibacterial properties, but also is compounded with the antibacterial masterbatch, and has an extremely long bacteriostatic time, and can play a synergistic bactericidal function.

[0020] The present invention uses grafted silica in combination with homopolypropylene and polylactic acid, which can form stable chemical crosslinking points in the matrix, not only improving the density of the product, having excellent mechanical properties when subjected to external forces, effectively enhancing the mechanical properties of the product, but also enabling the system to have excellent barrier properties, comprehensively enhancing the properties of the product.

[0021] The present invention effectively improves the degradation performance of the sterile bag, reduces the impact on the environment caused by the sterile bag, has a reasonable layer structure design, excellent stability of the product film, and better durability. Among them, degradable raw materials are used, which can be degraded under natural conditions, effectively solving the problem of white pollution. It also has more excellent barrier properties and good mechanical properties, and is suitable for large-scale popularization and application. Description of the Drawings

[0022] Figure 1 It is a comparison diagram of the water contact angles of the sterile bags obtained in Example 5 and Comparative Examples 1-2.

[0023] Figure 2 It is a comparison diagram of the tensile strength and elongation at break of the plastic sterile films obtained in Example 5 and Comparative Examples 1-2.

[0024] Figure 3 It is a comparison diagram of the water vapor transmission rate and oxygen transmission rate of the plastic sterile films obtained in Example 5 and Comparative Examples 1-2.

[0025] Figure 4 It is a comparison diagram of the antibacterial rates of the plastic sterile films obtained in Example 5 and Comparative Examples 1-2. Detailed Embodiments

[0026] The present invention will be further explained below in conjunction with specific embodiments.

[0027] Example 1 A sterile bag that can block microorganisms is obtained by making a bag with a plastic sterile film; and the plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer.

[0028] The raw materials of the surface layer include: 500 g of homopolypropylene, 200 g of polylactic acid, 100 g of grafted silica, 50 g of antibacterial masterbatch, and 10 g of oleic acid amide; the raw materials of the intermediate layer include: 500 g of homopolypropylene, 150 g of branched starch, 10 g of 2.5-generation terminal amino polyamidoamine, 10 g of lauryl diethanolamide, and 10 g of erucic acid amide; the raw materials of the bottom layer include: 500 g of homopolypropylene, 200 g of polylactic acid, 100 g of grafted silica, 50 g of antibacterial masterbatch, and 10 g of oleic acid amide.

[0029] The above grafted silica is prepared by the following steps: Add 100 g of activated silica to 500 g of N,N-dimethylformamide, add 50 g of polyvinyl alcohol and 1 g of triethylenediamine, perform ultrasonic treatment for 1 h with an ultrasonic frequency of 20 kHz, stir at a temperature of 40 °C for 1 h with a stirring speed of 500 r / min, filter, wash, dry under vacuum, and pulverize. The activated silica used therein is prepared by the following specific operations: Add 50 g of tetraethyl orthosilicate and 100 g of bamboo charcoal powder to 500 g of an ethanol aqueous solution with a mass fraction of 40%, stir for 10 min with a stirring speed of 200 r / min, add 10 g of hydrochloric acid with a concentration of 1 mol / L, continue to stir for 1 h, keep warm at a temperature of 50 °C for 1 h, filter, wash, and dry under vacuum.

[0030] The above antibacterial masterbatch is prepared by the following steps: Mix 100 g of homopolypropylene, 10 g of calcium carbonate, 5 g of antioxidant 1076, 5 g of antioxidant 626, and 10 g of didodecyldimethylammonium chloride evenly, feed them into a twin-screw extruder, extrude at a temperature of 180 °C, cool after strand drawing, pelletize, and dry.

[0031] The preparation method of the above sterile bag capable of blocking microorganisms includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer respectively, feed them into a high-speed mixer and stir evenly, after co-extruding the three layers at 195 °C, attach the obtained melt to a cold drum at a temperature of 5 °C to form a thick sheet, perform synchronous biaxial stretching, the stretching temperature is 150 °C, the stretching ratio is 2×2, shape at a temperature of 180 °C for 5 s, perform corona treatment after cooling, wind up, and make bags.

[0032] Example 2 A sterile bag capable of blocking microorganisms is obtained by making a bag with a plastic sterile film; and the plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer.

[0033] The raw materials of the surface layer include: 1000 g of homopolypropylene, 400 g of polylactic acid, 200 g of grafted silica, 150 g of antibacterial masterbatch, and 20 g of erucic acid amide; the raw materials of the intermediate layer include: 1000 g of homopolypropylene, 300 g of branched starch, 50 g of 2.5-generation amino-terminated polyamidoamine, 20 g of lauryldiethanolamide, and 20 g of oleic acid amide; the raw materials of the bottom layer include: 1000 g of homopolypropylene, 400 g of polylactic acid, 200 g of grafted silica, 150 g of antibacterial masterbatch, and 20 g of erucic acid amide.

[0034] The above grafted silica is prepared by the following steps: Add 200 g of activated silica into 1000 g of N,N-dimethylformamide, add 100 g of polyvinyl alcohol and 10 g of triethylenediamine, perform ultrasonic treatment for 2 h, with the ultrasonic frequency of 30 kHz, stir at a temperature of 60 °C for 2 h, with the stirring speed of 1000 r / min, filter, wash, dry in vacuum, and pulverize. The activated silica used is prepared by the following specific operation: Add 150 g of tetraethyl orthosilicate and 200 g of bamboo charcoal powder into 1000 g of ethanol aqueous solution with a mass fraction of 60%, stir for 30 min, with the stirring speed of 600 r / min, add 30 g of hydrochloric acid with a concentration of 2 mol / L, continue to stir for 2 h, keep warm at a temperature of 70 °C for 2 h, filter, wash, and dry in vacuum.

[0035] The above antibacterial masterbatch is prepared by the following steps: Mix 300 g of homopolypropylene, 20 g of kaolin, 6.67 g of antioxidant 1076, 13.33 g of antioxidant 626, and 20 g of didodecyldimethylammonium bromide evenly, feed them into a twin-screw extruder, extrude at a temperature of 220 °C, cool after strand drawing, pelletize, and dry.

[0036] The preparation method of the above sterile bag capable of blocking microorganisms includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer respectively, feed them into a high-speed mixer and stir evenly, after co-extruding three layers at 210 °C, attach the obtained melt to a cold drum at a temperature of 12 °C to form a thick sheet, perform synchronous biaxial stretching, with the stretching temperature of 165 °C and the stretching ratio of 4×4, shape at a temperature of 190 °C for 15 s, corona treat after cooling, wind up, and make bags.

[0037] Example 3 A sterile bag capable of blocking microorganisms is obtained by making bags with a plastic sterile film; and the plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer.

[0038] The raw materials of the surface layer include: 700 g of homopolypropylene, 350 g of polylactic acid, 120 g of grafted silica, 120 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide; the raw materials of the intermediate layer include: 700 g of homopolypropylene, 240 g of branched starch, 20 g of 2.5-generation terminal amino polyamidoamine, 17 g of lauryldiethanolamide, and 13 g of ethylene bisstearamide; the raw materials of the bottom layer include: 900 g of homopolypropylene, 250 g of polylactic acid, 180 g of grafted silica, 80 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide.

[0039] The above grafted silica is prepared by the following steps: Add 180 g of activated silica to 700 g of N,N-dimethylformamide, add 90 g of polyvinyl alcohol and 3 g of triethylenediamine, perform ultrasonic treatment for 100 min at an ultrasonic frequency of 21 kHz, stir at a temperature of 55 °C for 80 min at a stirring speed of 900 r / min, filter, wash, dry in vacuum, and pulverize. The activated silica used therein is prepared by the following specific operations: Add 80 g of tetraethyl orthosilicate and 180 g of bamboo charcoal powder to 700 g of an ethanol aqueous solution with a mass fraction of 55%, stir for 15 min at a stirring speed of 500 r / min, add 15 g of hydrochloric acid with a concentration of 1.8 mol / L, continue to stir for 80 min, keep warm at a temperature of 65 °C for 80 min, filter, wash, and dry in vacuum.

[0040] The above antibacterial masterbatch is prepared by the following steps: Mix 250 g of homopolypropylene, 12 g of kaolin, 7 g of antioxidant 1076, 10 g of antioxidant 626, and 12 g of dioctyldimethylammonium bromide evenly, feed them into a twin-screw extruder, extrude at a temperature of 210 °C, cool after strand drawing, pelletize, and dry.

[0041] The method for preparing the above aseptic bag capable of blocking microorganisms includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer respectively, feed them into a high-speed mixer and stir evenly, co-extrude the three layers at 200 °C, attach the obtained melt to a cold drum at a temperature of 10 °C to form a thick sheet, perform synchronous biaxial stretching, with a stretching temperature of 155 °C and a stretching ratio of 3.5×2.5, shape at a temperature of 188 °C for 8 s, perform corona treatment after cooling, wind up, and make bags.

[0042] Example 4 An aseptic bag capable of blocking microorganisms is obtained by making bags with a plastic aseptic film; and the plastic aseptic film includes: a surface layer, an intermediate layer covering one side of the surface layer, and a bottom layer covering one side of the intermediate layer.

[0043] The raw materials of the surface layer include: 900 g of homopolypropylene, 250 g of polylactic acid, 180 g of grafted silica, 80 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide; the raw materials of the intermediate layer include: 900 g of homopolypropylene, 200 g of branched starch, 40 g of 2.5-generation terminal amino polyamidoamine, 13 g of lauryldiethanolamide, and 17 g of ethylene bisstearamide; the raw materials of the bottom layer include: 700 g of homopolypropylene, 350 g of polylactic acid, 120 g of grafted silica, 120 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide.

[0044] The above grafted silica is prepared by the following steps: Add 120 g of activated silica into 900 g of N,N-dimethylformamide, add 70 g of polyvinyl alcohol and 7 g of triethylenediamine, perform ultrasonic treatment for 80 min at an ultrasonic frequency of 27 kHz, stir at a temperature of 45 °C for 100 min with a stirring speed of 700 r / min, filter, wash, dry in vacuum, and pulverize. The activated silica used therein is prepared by the following specific operation: Add 120 g of tetraethyl orthosilicate and 120 g of bamboo charcoal powder into 900 g of an ethanol aqueous solution with a mass fraction of 45%, stir for 25 min with a stirring speed of 300 r / min, add 25 g of hydrochloric acid with a concentration of 1.2 mol / L, continue stirring for 100 min, keep warm at a temperature of 55 °C for 100 min, filter, wash, and dry in vacuum.

[0045] The above antibacterial masterbatch is prepared by the following steps: Mix 150 g of homopolypropylene, 18 g of talcum powder, 6 g of antioxidant 1076, 7 g of antioxidant 626, and 18 g of dioctyldimethylammonium bromide evenly, feed them into a twin-screw extruder, extrude at a temperature of 190 °C, cool after strand drawing, pelletize, and dry.

[0046] The method for preparing the above sterile bag capable of blocking microorganisms includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer respectively, feed them into a high-speed mixer and stir evenly. After co-extruding the three layers at 205 °C, attach the obtained melt to a cold drum at a temperature of 7 °C to form a thick sheet, perform synchronous biaxial stretching at a stretching temperature of 160 °C with a stretching ratio of 2.5×3.5, shape at a temperature of 182 °C for 12 s, corona treat after cooling, wind up, and make bags.

[0047] Example 5 A sterile bag capable of blocking microorganisms is obtained by making bags with a plastic sterile film; and the plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer.

[0048] The raw materials of the surface layer include: 800 g of homopolypropylene, 300 g of polylactic acid, 150 g of grafted silica, 100 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide; the raw materials of the intermediate layer include: 800 g of homopolypropylene, 220 g of branched starch, 30 g of 2.5-generation terminal amino polyamidoamine, 15 g of lauryl diethanolamide, and 15 g of ethylene bisstearamide; the raw materials of the bottom layer include: 800 g of homopolypropylene, 300 g of polylactic acid, 150 g of grafted silica, 100 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide.

[0049] The above grafted silica is prepared by the following steps: Add 150 g of activated silica into 800 g of N,N-dimethylformamide, add 80 g of polyvinyl alcohol and 5 g of triethylenediamine, perform ultrasonic treatment for 90 min at an ultrasonic frequency of 24 kHz, stir at a temperature of 50 °C for 90 min with a stirring speed of 800 r / min, filter, wash, dry in vacuum, and pulverize. The activated silica used therein is prepared by the following specific operations: Add 100 g of tetraethyl orthosilicate and 150 g of bamboo charcoal powder into 800 g of an ethanol aqueous solution with a mass fraction of 50%, stir for 20 min with a stirring speed of 400 r / min, add 20 g of hydrochloric acid with a concentration of 1.5 mol / L, continue to stir for 90 min, keep warm at a temperature of 60 °C for 90 min, filter, wash, and dry in vacuum.

[0050] The above antibacterial masterbatch is prepared by the following steps: Mix 200 g of homopolypropylene, 15 g of diatomite, 6 g of antioxidant 1076, 9 g of antioxidant 626, and 15 g of dioctyldimethylammonium chloride evenly, feed them into a twin-screw extruder, extrude at a temperature of 200 °C, cool after strand drawing, pelletize, and dry.

[0051] The preparation method of the above aseptic bag capable of blocking microorganisms includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer respectively, feed them into a high-speed mixer and stir evenly, co-extrude the three layers at 202 °C, attach the obtained melt to a cold drum at a temperature of 8 °C to form a thick sheet, perform synchronous biaxial stretching, with a stretching temperature of 158 °C and a stretching ratio of 3×3, shape at a temperature of 185 °C for 10 s, corona treat after cooling, wind up, and make bags.

[0052] Comparative Example 1 An aseptic bag capable of blocking microorganisms is obtained by making bags with a plastic aseptic film; and the plastic aseptic film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer.

[0053] The raw materials of the surface layer include: 800 g of homopolypropylene, 300 g of polylactic acid, 150 g of grafted silica, 100 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide; the raw materials of the intermediate layer include: 800 g of homopolypropylene, 220 g of branched starch, 30 g of 2.5-generation terminal amino polyamidoamine, 15 g of lauryldiethanolamide, and 15 g of ethylene bisstearamide; the raw materials of the bottom layer include: 800 g of homopolypropylene, 300 g of polylactic acid, 150 g of grafted silica, 100 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide.

[0054] The above grafted silica is prepared by the following steps: Add 150 g of activated silica to 800 g of N,N-dimethylformamide, add 80 g of polyvinyl alcohol and 5 g of triethylenediamine, perform ultrasonic treatment for 90 min at an ultrasonic frequency of 24 kHz, stir at a temperature of 50 °C for 90 min with a stirring speed of 800 r / min, filter, wash, dry in vacuum, and pulverize. The activated silica used therein is prepared by the following specific operations: Add 100 g of tetraethyl orthosilicate to 800 g of an ethanol aqueous solution with a mass fraction of 50% and stir for 20 min with a stirring speed of 400 r / min, add 20 g of hydrochloric acid with a concentration of 1.5 mol / L, continue stirring for 90 min, keep warm at a temperature of 60 °C for 90 min, filter, wash, dry in vacuum, and mix evenly with 150 g of bamboo charcoal powder.

[0055] The above antibacterial masterbatch is prepared by the following steps: Mix 200 g of homopolypropylene, 15 g of diatomite, 6 g of antioxidant 1076, 9 g of antioxidant 626, and 15 g of dioctyldimethylammonium chloride evenly, feed them into a twin-screw extruder, extrude at a temperature of 200 °C, cool after strand drawing, pelletize, and dry.

[0056] The preparation method of the above sterile bag capable of blocking microorganisms includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer respectively, feed them into a high-speed mixer and stir evenly, co-extrude the three layers at 202 °C, attach the obtained melt to a cold drum at a temperature of 8 °C to form a thick sheet, perform synchronous biaxial stretching, with a stretching temperature of 158 °C and a stretching ratio of 3×3, shape at a temperature of 185 °C for 10 s, corona treat after cooling, wind up, and make bags.

[0057] Comparative Example 2 A sterile bag capable of blocking microorganisms is obtained by making bags with a plastic sterile film; and the plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer.

[0058] The raw materials of the surface layer include: 800 g of homopolypropylene, 300 g of polylactic acid, 150 g of activated silica, 100 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide; the raw materials of the intermediate layer include: 800 g of homopolypropylene, 220 g of branched starch, 30 g of 2.5-generation terminal amino polyamidoamine, 15 g of lauryl diethanolamide, and 15 g of ethylene bisstearamide; the raw materials of the bottom layer include: 800 g of homopolypropylene, 300 g of polylactic acid, 150 g of activated silica, 100 g of antibacterial masterbatch, and 15 g of ethylene bisstearamide.

[0059] The above activated silica is prepared by the following specific operations: 100 g of tetraethyl orthosilicate and 150 g of bamboo charcoal powder are added to 800 g of an ethanol aqueous solution with a mass fraction of 50%, stirred for 20 min at a stirring speed of 400 r / min, 20 g of hydrochloric acid with a concentration of 1.5 mol / L is added, and stirring is continued for 90 min. It is kept warm at 60 °C for 90 min, filtered, washed, and dried under vacuum.

[0060] The above antibacterial masterbatch is prepared by the following steps: 200 g of homopolypropylene, 15 g of diatomite, 6 g of antioxidant 1076, 9 g of antioxidant 626, and 15 g of dioctyldimethylammonium chloride are mixed evenly, fed into a twin-screw extruder, extruded at 200 °C, cooled after being drawn into strips, pelletized, and dried.

[0061] The preparation method of the above aseptic bag capable of blocking microorganisms includes the following steps: The raw materials of the surface layer, the middle layer, and the bottom layer are respectively mixed, fed into a high-speed mixer and stirred evenly. After co-extrusion of three layers at 202 °C, the obtained melt is attached to a cold drum at 8 °C to form a thick sheet, which is synchronously biaxially stretched. The stretching temperature is 158 °C, the stretching ratio is 3×3, it is shaped at 185 °C for 10 s, corona-treated after cooling, wound up, and made into bags.

[0062] The water contact angles of the aseptic bags obtained in Example 5 and Comparative Examples 1-2 are measured using a contact angle goniometer. The contact angles are measured at 5 different positions of each group of aseptic bag films, and the average value is calculated. As Figure 1 shown, the water contact angle of the aseptic bag obtained in Example 5 is the highest, which is better than that of Comparative Examples 1-2 (P < 0.05).

[0063] With reference to GB / T 1040.3-2006 "Plastics - Determination of tensile properties - Part 3: Test conditions for films and sheets", the tensile strength and elongation at break of the plastic aseptic films obtained in Example 5 and Comparative Examples 1-2 are measured, and 3 parallels are set for each group. As Figure 2 shown, the tensile strength of the plastic aseptic film obtained in Example 5 is the highest, while the elongation at break is the lowest, which is better than that of Comparative Examples 1-2 (P < 0.05).

[0064] The water vapor transmission rate of the plastic sterile films obtained in Example 5 and Comparative Examples 1-2 was tested by the weight gain method in accordance with GB / T 1037-2021 "Determination of water vapor transmission properties of plastic films and sheets - Cup method for weight gain and weight loss". The test temperature was 38 °C, the humidity was 90%RH, the preheating time was 2h, the rotation interval was 10min, and 3 parallels were set for each group. The oxygen transmission rate of the plastic sterile films obtained in Example 5 and Comparative Examples 1-2 was tested in accordance with GB / T 1038.1-2022 "Plastics - Films and sheets - Test method for gas permeability - Part 1: Differential pressure method". The test temperature was 23 °C, the humidity was 50%RH, and the vacuum pumping time was 4h. Ensure that the sample surface is free of contamination and scratches, and 3 parallels are set for each group.

[0065] As Figure 3 shown, the water vapor transmission rate and oxygen transmission rate of the plastic sterile film obtained in Example 5 were the lowest, superior to those of Comparative Examples 1-2 (P < 0.05).

[0066] Multiple suspensions of Staphylococcus aureus (with a viable bacteria concentration of 1×10 8 cfu / mL) were prepared and separately added to 10 g of the plastic sterile films obtained in Example 5 and Comparative Examples 1-2, and then cultured in an incubator at 37 °C for 24 h; for the blank group, a suspension of Staphylococcus aureus (with a viable bacteria concentration of 1×10 8 cfu / mL) was cultured in an incubator at 37 °C for 24 h. After the culture, the viable bacteria concentration in each group of suspensions was detected again, and the antibacterial rate was calculated.

[0067] Antibacterial rate = (viable bacteria concentration in the blank group - viable bacteria concentration in the film group) ÷ viable bacteria concentration in the blank group × 100% As Figure 4 shown, the plastic sterile film obtained in Example 5 had the highest antibacterial rate, superior to those of Comparative Examples 1-2 (P < 0.05).

[0068] The applicant believes that: This is because the present invention uses bamboo charcoal powder as an attachment point, on which nano-silica is in-situ deposited to form activated silica, and then under the catalysis of triethylenediamine, polyvinyl alcohol is grafted onto it, greatly improving the interfacial affinity with homopolypropylene and polylactic acid. It not only endows the sterile bag with excellent antibacterial properties, but also when compounded with antibacterial masterbatch, has an extremely long antibacterial time and can play a synergistic bactericidal function; at the same time, the present invention uses grafted silica compounded with homopolypropylene and polylactic acid, which can form stable chemical cross-linking points in the matrix, not only improving the density of the product, having excellent mechanical properties when subjected to external forces and effectively improving the mechanical properties of the product, but also promoting the system to have excellent barrier properties and comprehensively enhancing the performance of the product.

[0069] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A sterile bag capable of blocking microorganisms, characterized in that, It is obtained by making bags with a plastic sterile film; The plastic sterile film includes: a surface layer, an intermediate layer covered on one side of the surface layer, and a bottom layer covered on one side of the intermediate layer; Among them, the raw materials of the surface layer and the bottom layer both include: homopolypropylene, polylactic acid, grafted silica, antibacterial masterbatch, and lubricant, while the raw materials of the intermediate layer include: homopolypropylene, branched starch, amino-terminated polyamidoamine, antistatic agent, lubricant; The grafted silica is obtained by reacting activated silica with polyvinyl alcohol and triethylenediamine.

2. The sterile bag capable of blocking microorganisms according to claim 1, wherein, The grafted silica is prepared by the following specific steps: Add activated silica to N,N-dimethylformamide, add polyvinyl alcohol and triethylenediamine, and perform ultrasonic treatment for 1-2 h, stir at 40-60 °C for 1-2 h, filter, wash, vacuum dry, and pulverize; During the preparation of the grafted silica, the mass ratio of activated silica, polyvinyl alcohol, and triethylenediamine is 10-20:5-10:0.1-1.

3. The sterile bag capable of blocking microorganisms according to claim 2, wherein, During the preparation of the grafted silica, the ultrasonic frequency is 20-30 kHz.

4. The sterile bag capable of blocking microorganisms according to claim 1, wherein The activated silica is prepared by the following specific operations: Add tetraethyl orthosilicate and bamboo charcoal powder to an ethanol aqueous solution and stir for 10-30 min, add hydrochloric acid and continue to stir for 1-2 h, keep warm at 50-70 °C for 1-2 h, filter, wash, and vacuum dry.

5. The sterile bag capable of blocking microorganisms according to claim 4, wherein The concentration of hydrochloric acid is 1-2 mol / L, and the mass ratio of tetraethyl orthosilicate, bamboo charcoal powder, and hydrochloric acid is 5-15:10-20:1-3.

6. The sterile bag capable of blocking microorganisms according to claim 1, wherein, The lubricant is at least one of ethylene bisstearamide, oleic acid amide, and erucic acid amide.

7. The sterile bag capable of blocking microorganisms according to claim 1, wherein The antibacterial masterbatch is prepared by the following steps: Mix homopolypropylene, opening agent, antioxidant, and double-chain quaternary ammonium salt bacteriostatic agent evenly, extrude at 180-220 °C, and dry.

8. The sterile bag capable of blocking microorganisms according to claim 7, wherein, The mass ratio of homopolypropylene, opening agent, antioxidant, and double-chain quaternary ammonium salt bacteriostatic agent is 10-30:1-2:1-2:1-2.

9. The sterile bag capable of blocking microorganisms according to claim 7, wherein The opening agent is at least one of talcum powder, diatomaceous earth, kaolin, and calcium carbonate; the double-chain quaternary ammonium salt bacteriostatic agent includes: at least one of didecyldimethylammonium chloride, didecyldimethylammonium bromide, dioctyldimethylammonium chloride, and dioctyldimethylammonium bromide; the antioxidant includes: antioxidant 1076 and antioxidant 626, and the mass ratio of antioxidant 1076 and antioxidant 626 is 1:1-2.

10. A method for preparing a sterile bag capable of blocking microorganisms according to any one of claims 1-9, characterized in that, It includes the following steps: Mix the raw materials of the surface layer, the intermediate layer, and the bottom layer evenly, after co-extruding the three layers, attach the obtained melt to a cold drum to form a thick sheet, perform synchronous biaxial stretching, the stretching temperature is 150-165 °C, the stretching ratio is 2-4×2-4, shape at 180-190 °C for 5-15 s, perform corona treatment after cooling, and make bags.

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