A modified moisture absorbing composite film and a method for preparing the same

Abstract

The application belongs to the technical field of aluminum-plastic composite film, and specifically provides a modified moisture-absorbing composite film and a preparation method thereof, and the preparation steps comprise the following: according to the overlapping sequence from outside to inside, PET film, Al foil and modified PE film are coated and combined, and then maturation and drying are performed to obtain the modified moisture-absorbing composite film; the preparation steps of the modified PE film comprise the following: polyethylene masterbatch and modified zeolite are taken, mixed, and then extruded and blown into a film to obtain the modified PE film; the preparation steps of the modified zeolite comprise the following: calcined kaolin, crystal seeds and sodium carbonate are mixed and ground, water is added for dispersion, the silicon-aluminum ratio is adjusted to 3.3-3.5, aging is performed, then temperature is increased for crystallization treatment, and the product is dried and sieved to obtain the modified zeolite; the modified zeolite prepared in the application is added to a PE base material, and the modified PE film obtained after film blowing molding has good moisture absorption and antibacterial properties.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum-plastic composite film, and particularly relates to a modified moisture-absorbing composite film and a preparation method thereof. BACKGROUND

[0002] The aluminum-plastic composite film is a kind of multi-layer flexible packaging material. Compared with the traditional single-layer plastic film, the aluminum-plastic composite film can effectively block oxygen, water vapor, light and other external factors through the synergistic effect of the multi-layer structure, thereby significantly prolonging the shelf life of the content. The aluminum-plastic composite film combines the flexibility, printability of plastic and the high barrier property of aluminum foil, and has obvious advantages in food packaging, medicines, electronic components and the like.

[0003] The aluminum-plastic composite film is mainly composed of a printing layer, a barrier layer (aluminum foil) and a heat-sealing layer which are compounded by an adhesive. The heat-sealing layer is usually polyethylene (PE) or cast polypropylene (CPP). Compared with CPP, PE has more excellent heat adhesion, low-temperature heat-sealing property and flexibility, and has a lower cost, which is suitable for large-scale production. Although PE performs well in the heat-sealing layer, it has the defect of poor moisture absorption. The products (such as moisture-sensitive medicines or electronic components) packaged by PE are easily damaged in a high-temperature and high-humidity environment. In order to improve the moisture absorption, the industry usually adds a moisture-absorbing component, such as zeolite molecular sieve, to PE to reduce the humidity inside the package through physical adsorption. However, the zeolite molecular sieve is an inorganic material, and has poor compatibility with the PE organic matrix. The prepared film product is prone to perforation, damage and other problems, which seriously affects the packaging effect.

[0004] The patent application file with the application publication number CN112757735A discloses an antibacterial easy-to-peel moisture-absorbing PE film, a preparation method and a packaging structure. The PE film body includes an outer printing / composite layer, a moisture-absorbing layer and an antibacterial easy-to-peel layer. Zeolite molecular sieve is used as a moisture-absorbing agent in the moisture-absorbing layer to provide a moisture-proof and moisture-absorbing function for the packaging content. In combination with the modified nano-ZnO inorganic antibacterial agent in the antibacterial easy-to-peel layer, the moisture absorption and antibacterial properties of the PE film are comprehensively improved.

[0005] In the above scheme, although a PE film with antibacterial and moisture-absorbing properties is prepared by a multi-layer composite form, the multi-layer composite form will inevitably increase the thickness of the PE film. When the film is used for coating with Al foil, the thickness of the aluminum-plastic film will be further increased. Moreover, since the modified nano-ZnO antibacterial agent is embedded in the PE system through melt blending in the antibacterial easy-to-peel layer and directly contacts the packaging content, the precipitation and phase separation problems will be aggravated. Therefore, it is necessary to find a modified moisture-absorbing film with moisture absorption, antibacterial properties and reduced precipitation of antibacterial active metal ions and a preparation method thereof. SUMMARY

[0006] In order to further inhibit the antibacterial group and improve the compatibility of inorganic moisture-absorbing components and PE base material, the application provides a modified moisture-absorbing composite film and a preparation method thereof.

[0007] The application first provides a preparation method of a modified moisture-absorbing composite film, and the preparation steps include the following:

[0008] According to the folding sequence from outside to inside, the PET film, the Al foil and the modified PE film are coated and combined, and then matured and dried to obtain the modified moisture-absorbing composite film.

[0009] The preparation steps of the modified PE film include the following:

[0010] The polyethylene master batch and the modified zeolite are mixed, and then extruded and blown into a film to obtain the modified PE film.

[0011] The preparation steps of the modified zeolite include the following:

[0012] The calcined kaolin, the seed crystal and the sodium carbonate are mixed and ground, dispersed with water, and adjusted to a silicon-aluminum ratio of 3.3-3.5, and then placed for aging, and then subjected to temperature crystallization treatment, and the product is dried, crushed and sieved to obtain the modified zeolite.

[0013] The mass ratio of the calcined kaolin, the seed crystal and the sodium carbonate is (40-60):(1-2):(6-8), and the temperature crystallization treatment is adjusted to a temperature of 120-150 DEG C for 15-18 hours.

[0014] The seed crystal is obtained by grafting reaction of methyl methacrylate, glycidyl methacrylate and polyethylene imine after microemulsion polymerization and PE-g-MAH.

[0015] The coating and combining operation is performed with a sizing amount controlled at 20±2 g / m 2 ;

[0016] The mass ratio of the polyethylene master batch and the modified zeolite is (120-150):(5-8).

[0017] The extrusion and film blowing treatment is set to a cylinder zone temperature of 150-165 DEG C, a die temperature of 150-155 DEG C, and a blowing ratio of (2-2.5):1.

[0018] The thickness of the modified PE film is 50-55 microns.

[0019] By adopting the technical scheme, the modified zeolite is mixed in the PE base material in the melting process, the antibacterial property of the PE blown film is improved, and the compatibility problem of the inorganic component and the base material is reduced; the modified zeolite takes the silicon-rich aluminum sol solution as a precursor, is mixed with seeds, and is hydrothermally crystallized; in the seed preparation process, the elastomer is obtained after the polymerization of the organic monomer microemulsion, the introduced polyethylene imine organic amine chain segment can strengthen the template effect of the seed, and in the immersion treatment process, the divalent copper ions and the divalent zinc ions in the immersion solution are chelated by virtue of the amine-rich structure of the molecular chain segment, the silicon-rich aluminum sol takes the elastomer as a core in the subsequent hydrothermal crystallization of the zeolite, and the chelated metal ions are embedded in the zeolite framework, so that the migration of the metal ions from the zeolite system is inhibited; the elastomer is grafted and modified by the long-chain PE-g-MAH, the long-chain nonpolar chain segment is introduced on the surface of the elastomer, the nonpolar grafted PE chain segment exposed on the surface of the zeolite crystallization product after crushing has high compatibility with the base material, and the influence of phase separation on the film product can be reduced through molecular chain entanglement.

[0020] Further, the preparation step of the seed includes the following:

[0021] S01. Methyl methacrylate, glycidyl methacrylate and initiator are mixed, low-speed ultrasonic dispersion is performed, and a pre-dispersion liquid is obtained;

[0022] S02. The emulsifier and polyethylene imine are mixed, dissolved with water, then the pre-dispersion liquid is added dropwise, ultrasonic emulsification is performed, and then heating reaction is performed; after demulsification, filtration, and water washing, the intermediate product A is obtained by treating in an immersion solution, filtering again, and drying.

[0023] S03. PE-g-MAH is taken, xylene is added, and then the mixture is dissolved by heating; then nitrogen is introduced, intermediate product A is added, and catalytic reaction is performed; then cooling and drying are performed, and the product is obtained.

[0024] In the step S01, the mass ratio of methyl methacrylate, glycidyl methacrylate and initiator is (7-7.5):(3.2-3.5):(0.1-0.2); and the initiator is azobisisobutyronitrile.

[0025] Further, in the step S02, the heating reaction is performed at a temperature of 60-65℃ for 6-8h.

[0026] By adopting the technical scheme, the pre-dispersed liquid is used as an oil phase, and a micro-nano suspension emulsion is formed after ultrasonic emulsification in an aqueous phase; during a subsequent temperature rising reaction process, monomer components and initiators are polymerized in the emulsion particles to obtain an elastomer polymer, and part of polyethyleneimine molecules participate in an initiation reaction at a water-oil interface to introduce a polar polyethyleneimine segment on the surface of the elastomer; by means of polar groups such as amine groups on the grafted polyethyleneimine segment, divalent zinc ions and divalent copper metal ions can be effectively captured during impregnation, so that the surface of the elastomer is assembled with metal active centers having antibacterial activity.

[0027] Further, in the step S02, the preparation step of the impregnating solution comprises the following steps: taking zinc acetate and copper sulfate, dispersing in water, adding ammonia water dropwise, stirring, and then adding urea for continuous treatment to obtain the impregnating solution; the ratio of the zinc acetate, the copper sulfate, the ammonia water and the urea is (0.5-0.8) g:(1.2-1.7) g:(1-2) mL:(0.2-0.3) g.

[0028] Further, in the step S03, the catalyst used in the catalytic reaction is triphenylphosphine, the temperature is set to 110-120 DEG C, and the reaction lasts for 3-5 h.

[0029] By adopting the technical scheme, under the action of the catalyst triphenylphosphine, the residual epoxy groups on the elastomer polymer react with maleic anhydride to introduce non-polar PE segments on the molecular chain of the elastomer. After crystallization and crushing treatment, the organic segments extending from the surface of the zeolite particles can not only improve the compatibility between the zeolite and the PE matrix, but also play a role similar to that of a branched chain structure to enhance the physical combination with the PE molecular chain, thereby inhibiting the phase separation of the PE base material and the modified zeolite.

[0030] The application further provides a modified moisture-absorbing composite film prepared by the preparation method.

[0031] Compared with the prior art, the application has the following beneficial effects:

[0032] 1、The application prepares an organic elastomer by microemulsion polymerization, and uses the organic elastomer as a seed precursor to obtain a modified zeolite by hydrothermal crystallization. The modified zeolite is mixed in a PE masterbatch, and a modified PE film with good antibacterial and moisture absorption performance is prepared by melt extrusion and film blowing. The organic elastomer is a high chelation active composition obtained by reacting methyl methacrylate and glycidyl methacrylate as polymerization monomers and polyethyleneimine, and can form a stable chelation structure with divalent zinc ions, divalent copper ions and other antibacterial metal ions in the immersion process. In the subsequent hydrothermal crystallization process of the zeolite, the seed and the chelated metal ions are embedded in the zeolite framework together, which gives the zeolite persistent antibacterial activity and effectively inhibits the leaching of metal ions. In addition, due to the introduction of the polar seed, the polarity of the zeolite core is enhanced, and water molecules can be physically adsorbed through the porous structure of the zeolite, and can also be attracted by the polar sites in the core, thereby significantly improving the overall moisture absorption capacity of the film.

[0033] 2、The application uses PE-g-MAH grafting treatment to introduce polyethylene segments on the surface of the seed, and the partially exposed polyethylene segments on the surface of the modified zeolite crystallization product can have good compatibility with the PE base material in the melting stage, and can also have a physical entanglement effect similar to the branched chain to improve the compatibility of the modified zeolite with the PE base material. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The test results of the moisture absorption performance of the modified PE films of Examples 1-4 and Comparative Examples 1-3 of the application.

[0035] Figure 2 The test results of the active metal ion desorption performance of the modified PE films of Examples 1-4 and Comparative Examples 1-3 of the application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0038] In the case of using "include", "have", and "contain" described in this document, it is intended to cover non-exclusive inclusion, unless the explicit limiting language such as "only", "consisting of", etc. is used, another component can also be added.

[0039] The words "preferably", "more preferably", "most preferably", "particularly", "more particularly", "particularly preferably", and "most particularly" in the specification are used to describe the embodiments of the application. However, it is to be understood that the words "preferably", "more preferably", "most preferably", "particularly", "more particularly", "particularly preferably", and "most particularly" are not used to limit alternatives that can also be preferred in some circumstances to those embodiments described by the words "preferably", "more preferably", "most preferably", "particularly", "more particularly", "particularly preferably", and "most particularly". Furthermore, the use of these words in some areas of the specification is not intended to mean that other embodiments of the application in other areas are not also preferred.

[0040] In the specification, "further", "furthermore", "in addition", and the like are used to describe purposes and are not to be construed as limiting the scope of protection of the present application.

[0041] In the specification, "at least one" means one or more, such as one, two, and more than two. "Multiple" or "several" means at least two, such as two, three, and the like. "Multiple layers" means at least two layers, such as two layers, three layers, and the like, unless otherwise explicitly specified. In the description of the present application, "several" means at least one, such as one, two, and the like, unless otherwise explicitly specified.

[0042] When a numerical range is disclosed herein, the range is to be construed as continuous, and to include each and every value within the range, as well as the minimum and maximum values of the range. Further, when a range is provided, it is intended to include the range and all individual values within the range. In other words, unless otherwise indicated, all ranges disclosed herein are to be understood as encompassing any and all sub-ranges subsumed therein. For example, a range of "1 to 10" is to be interpreted to include not only the individual numbers between 1 and 10, but also the range of numbers subsumed between 1 and 10, such as the range of 2 to 8.

[0043] If not otherwise specified, all steps of the present application can be carried out in sequence or randomly. For example, the method comprising steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method can further comprise step (c) means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc. Unless otherwise mentioned, the singular form of a term can include the plural form and should not be construed as having a quantity of one.

[0044] In the present application, "above" or "below" includes the number itself. For example, 1 below includes 1.

[0045] In the present application, room temperature refers to 0-40℃, including but not limited to 10-40℃, or further 20-30℃.

[0046] The present application will be further described by the following examples, but not limited to the scope of the present application.

[0047] When the examples give a numerical range, it should be understood that, unless otherwise specified in the present application, both endpoints of each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as commonly understood by those skilled in the art. If no specific conditions are mentioned in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If no manufacturer of all reagents or instruments is mentioned, it is a conventional product that can be purchased on the market. In addition to the specific methods, devices, materials used in the examples, any method, device and material of the prior art similar or equivalent to the methods, devices and materials described in the examples of the present application can also be used to realize the present application according to the mastery of the prior art by those skilled in the art and the description of the present application.

[0048] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods. Unless otherwise specified, the materials, reagents, etc. used in the following examples and comparative examples can be obtained from commercial channels.

[0049] The raw materials used in the examples and comparative examples of the present application are described as follows:

[0050] Methyl methacrylate, CP, 98% (containing 30 ppm MEHQ stabilizer), Shanghai Yinn Chemical Technology Co., Ltd;

[0051] Glycidyl methacrylate, AR, Guangdong Fangxin Biological Technology Co., Ltd;

[0052] Emulsifier OP-10, Tianjin Zhonghe Shengtai Chemical Co., Ltd.

[0053] Polyethyleneimine, AR, Mw=1800, Guangdong Yuansheng Chemical Reagent Co., Ltd.

[0054] PE-g-MAH, brand: TY1057H, Dongguan Zhangmutou Sikai Plastic Raw Material Operating Department

[0055] Polyurethane adhesive, model: SY-176, solid content 71.3%, Huizhou Saiya Industry Co., Ltd.

[0056] Polyethylene masterbatch, brand: AMF705HF, USA Shurmann Plastic Co.

[0057] Preparation Example 1

[0058] Take 0.5 g of zinc acetate, 1.2 g of copper sulfate, and dissolve in 50 mL of deionized water, then add 1 mL of ammonia water, adjust the magnetic stirring speed to 100 rpm, handle for 1 min, then add 0.2 g of urea, and prepare the dipping solution.

[0059] Take 7 g of methyl methacrylate, 3.2 g of glycidyl methacrylate, 0.1 g of azobisisobutyronitrile, and 60 mL of toluene at room temperature, and mix to obtain a pre-dispersion liquid.

[0060] Take 120 mL of deionized water, 1.5 g of emulsifier OP-10, and 1.2 g of polyethyleneimine (Mw=1800), and nitrogen is introduced into the system, and the magnetic stirring speed is adjusted to 400 rpm for continuous stirring, then 20 mL of the pre-dispersion liquid is added at a rate of 3 mL / min, and the ultrasonic wave is stopped after 5 min of 10 kHz ultrasonic wave, and the magnetic stirring speed is adjusted to 100 rpm, and the temperature is raised to 60°C for reaction for 6 h, then 50 mL of saturated sodium chloride solution is added to the system for continuous stirring for 10 min, then the solid part is filtered, washed with water for 2 times, then placed in 50 mL of the dipping solution, and the magnetic stirring speed is adjusted to 50 rpm for handling for 20 min, then filtered, and the filter collection is treated with cold water for 1 min, and dried to obtain the intermediate product A.

[0061] Take 3.4 g of PE-g-MAH (MAH grafting rate is 0.5%) and mix with 150 mL of toluene, then heat to 110°C, and adjust the magnetic stirring speed to 300 rpm for 1 h to obtain a homogeneous liquid, then introduce nitrogen, add 6.2 g of the intermediate product A and 0.15 g of triphenylphosphine, and stop heating after 3 h of reaction, and naturally cool to room temperature, and filter and dry to obtain the crystal seed.

[0062] Preparation Example 2

[0063] Take 0.6 g zinc acetate, 1.5 g copper sulfate, add 50 mL deionized water to dissolve, then add 1.2 mL ammonia water dropwise, adjust the magnetic stirring speed to 100 rpm, treat for 3 min, then add 0.25 g urea to prepare the impregnation solution.

[0064] Take 7.2 g methyl methacrylate, 3.2 g glycidyl methacrylate, 0.15 g azobisisobutyronitrile, and 65 mL toluene at room temperature, and ultrasonic at 5 kHz for 1 min to obtain a pre-dispersion liquid.

[0065] Take 120 mL deionized water, 1.5 g emulsifier OP-10, and 1.5 g polyethyleneimine (Mw=1800), and nitrogen gas is introduced into the system, and the magnetic stirring speed is adjusted to 400 rpm for continuous stirring, then 20 mL of the pre-dispersion liquid is added at a rate of 3.5 mL / min, ultrasonic at 10 kHz for 5 min, then stop ultrasonic, adjust the magnetic stirring speed to 200 rpm, and heat to 65°C for 7 h, then add 50 mL saturated sodium chloride solution to the system and continue stirring for 20 min, then filter and take the solid part, wash with water for 3 times, then place in 50 mL impregnation solution, adjust the magnetic stirring speed to 150 rpm, treat for 30 min, then filter, take the filter collection and treat with cold water for 2 min, dry to obtain intermediate product A.

[0066] Take 3.9 g PE-g-MAH (MAH grafting rate is 1%) and 150 mL toluene, then heat to 115°C, adjust the magnetic stirring speed to 300 rpm, and continue for 1.5 h to obtain a homogeneous liquid, then introduce nitrogen gas, add 6.8 g intermediate product A and 0.15 g triphenylphosphine, and react for 4.5 h, then stop heating, naturally cool to room temperature, filter and dry to obtain the crystal seed.

[0067] Preparation Example 3

[0068] Take 0.8 g zinc acetate, 1.7 g copper sulfate, add 50 mL deionized water to dissolve, then add 2 mL ammonia water dropwise, adjust the magnetic stirring speed to 100 rpm, treat for 1 min, then add 0.3 g urea to prepare the impregnation solution.

[0069] Take 7.5 g methyl methacrylate, 3.5 g glycidyl methacrylate, 0.2 g azobisisobutyronitrile, and 70 mL toluene at room temperature, and ultrasonic at 5 kHz for 2 min to obtain a pre-dispersion liquid.

[0070] Take 120 mL of deionized water, 2 g of emulsifier OP-10 and 1.5 g of polyethyleneimine (Mw=1800), nitrogen is introduced into the system, the magnetic stirring speed is adjusted to 500 rpm for continuous stirring, then 20 mL of pre-dispersion is added at a rate of 5 mL / min, ultrasonic for 10 min at 10 kHz, then stop ultrasonic, adjust the magnetic stirring speed to 200 rpm, heat to 65℃ for 8h, then add 50 mL of saturated sodium chloride solution to the system and continue stirring for 20 min, then filter the solid part, wash with water for 3 times, then put it in 50 mL of impregnation solution, adjust the magnetic stirring speed to 150 rpm, treat for 30 min, then filter, take the filter collection and treat with cold water for 2 min, dry to get intermediate product A.

[0071] Take 3.9 g of PE-g-MAH (MAH grafting rate is 1%) and 150 mL of dimethylbenzene, then heat to 120℃, adjust the magnetic stirring speed to 300 rpm, continue for 2h to get a homogeneous liquid, then introduce nitrogen, add 7.5 g of intermediate product A and 0.15 g of triphenylphosphine, stop heating after 5h of reaction, naturally cool to room temperature, filter and dry to get the crystal seed.

[0072] Example 1

[0073] The preparation steps of the modified moisture absorption composite film in this example are as follows:

[0074] Take PET film (thickness: 12 microns), modified PE film (thickness: 50 microns), according to 18.5 g / m 2 of glue amount, respectively single-sidedly coat polyurethane adhesive (model: SY-176), then the adhesive side is respectively compounded with Al foil (thickness: 7 microns) dark / light side, naturally air for 5h to get the modified moisture absorption composite film;

[0075] The preparation steps of the modified PE film in this example are as follows:

[0076] Take 200 g of calcined kaolin (1000 mesh, whiteness: 97%), 5 g of crystal seed and 30 g of sodium carbonate, grind and pass through a 1000 mesh sieve, then use 600 mL of deionized water to hydrate, then slowly add 20% sodium silicate aqueous solution, adjust the silicon aluminum ratio to 3.3, stir to get a mixed sol, then transfer to the reaction kettle after aging at room temperature for 10h, hydrothermal crystallization at 120℃ for 15h, then filter the solid part, dry and crush, then pass through a 1000 mesh sieve to get the modified zeolite.

[0077] Take 1.2 kg of polyethylene masterbatch and 50 g of modified zeolite, mix for 1 min, then put the mixture into a single screw extrusion blow molding machine, the screw diameter is 20 mm, the length-diameter ratio is 25:1, the barrel zone temperature is set to 150℃, the die temperature is 150℃, the blow-up ratio is 2:1 for extrusion blow molding, to get a film with a thickness of 50 microns.

[0078] The seed crystal is prepared according to Preparation Example 1.

[0079] Example 2

[0080] The preparation steps of the modified moisture absorption composite film in this example are as follows:

[0081] PET film (thickness: 12 microns) and modified PE film (thickness: 52 microns) are taken, and polyurethane adhesive (model: SY-176) is applied to one side of each film at a glue amount of 18 g / m 2 . Then, the adhesive side of each film is respectively laminated with the dark side and the bright side of an Al foil (thickness: 7 microns), and naturally air-dried for 6 h to obtain a modified moisture absorption composite film.

[0082] The preparation steps of the modified PE film in this example are as follows:

[0083] Take 250 g of calcined kaolin (1000 mesh, whiteness: 97%), mix 8 g of seed crystal with 35 g of sodium carbonate, grind and pass through a 1000 mesh sieve, hydrate with 600 mL of deionized water, then slowly add a 25% mass concentration sodium silicate aqueous solution, adjust the silicon aluminum ratio to 3.3, and stir to obtain a mixed sol. Then, after aging at room temperature for 15 h, transfer to a reaction kettle, hydrothermally crystallize at 145 ℃ for 16 h, then filter and dry the solid part, crush and pass through a 1000 mesh sieve to obtain a modified zeolite.

[0084] Take 1.35 kg of polyethylene masterbatch and mix with 70 g of modified zeolite for 5 min, then place the mixture in a single screw extrusion blow molding machine with a screw diameter of 20 mm and a length-diameter ratio of 25:1. Set the barrel zone temperature to 165 ℃, the die temperature to 155 ℃, and the blow-up ratio to 2.5:1 to perform extrusion blow film, obtaining a film with a thickness of 52 microns.

[0085] The seed crystal is prepared according to Preparation Example 2.

[0086] Example 3

[0087] The preparation steps of the modified moisture absorption composite film in this example are as follows:

[0088] PET film (thickness: 12 microns) and modified PE film (thickness: 55 microns) are taken, and polyurethane adhesive (model: SY-176) is applied to one side of each film at a glue amount of 22 g / m 2 . Then, the adhesive side of each film is respectively laminated with the dark side and the bright side of an Al foil (thickness: 7 microns), and naturally air-dried for 8 h to obtain a modified moisture absorption composite film.

[0089] The preparation steps of the modified PE film in this example are as follows:

[0090] Take 300 g calcined kaolin (1000 mesh, whiteness: 97%), 10 g seed mixed with 40 g sodium carbonate, grind and pass through a 1000 mesh sieve, use 700 mL deionized water to open, then slowly add a 25% mass concentration sodium silicate aqueous solution, adjust the silicon aluminum ratio to 3.5, stir to obtain a mixed sol, then transfer to the reaction kettle after room temperature aging for 15 h, hydrothermal crystallization at 150 ℃ for 18 h, then filter the solid part and dry, then crush and pass through a 1000 mesh sieve to obtain the modified zeolite.

[0091] Take 1.5 kg of polyethylene masterbatch and mix with 80 g of modified zeolite for 5 min, then place the mixture in a single screw extrusion blow molding machine with a screw diameter of 20 mm and a length-diameter ratio of 25:1, set the barrel zone temperature to 165 ℃, the die temperature to 155 ℃, and the blow-up ratio to 2.5:1 to perform extrusion blow film, obtaining a film thickness of 55 microns.

[0092] The seed is prepared according to Preparation Example 3.

[0093] Example 4

[0094] The difference between this example and Example 1 is only that the mass of the seed used in the preparation of the modified zeolite is 5.5 g.

[0095] The remaining steps are the same as those of Example 1.

[0096] Comparative Example 1

[0097] The difference between this comparative example and Example 1 is that an equal amount of carboxymethyl cellulose is used instead of polyethyleneimine to prepare the seed.

[0098] The remaining steps are the same as those of Example 1.

[0099] Comparative Example 2

[0100] The difference between this comparative example and Example 1 is that an equal amount of ABS-g-MAH (MAH grafting rate of 1.2%) is used instead of PE-g-MAH to prepare the seed.

[0101] The ABS-g-MAH is provided by Dongguan Nabichuan Plastic Co., Ltd.

[0102] The remaining steps are the same as those of Example 1.

[0103] Comparative Example 3

[0104] The difference between this comparative example and Example 1 is that the preparation steps of the modified zeolite are as follows:

[0105] Take 0.5 g of zinc acetate, 1.2 g of copper sulfate, 1 mL of ammonia water, and add 50 mL of deionized water to dissolve, then add 0.2 g of urea to prepare an impregnation solution.

[0106] Take 7 g of methyl methacrylate, 3.2 g of glycidyl methacrylate, 0.1 g of azobisisobutyronitrile and 60 mL of toluene at room temperature, and mix them to obtain a pre-dispersion liquid. Then, 5 kHz low-speed ultrasonic is used for 1 min.

[0107] Take 120 mL of deionized water, 1.5 g of emulsifier OP-10 and 1.2 g of polyethyleneimine, and then nitrogen is introduced into the system. The magnetic stirring speed is adjusted to 400 rpm for continuous stirring. Then, 20 mL of the pre-dispersion liquid is added dropwise at a rate of 3 mL / min. After 10 kHz ultrasonic is used for 5 min, the ultrasonic is stopped. The magnetic stirring speed is adjusted to 100 rpm, and the temperature is increased to 60°C for reaction for 6 h. Then, 50 mL of saturated sodium chloride solution is added into the system for continuous stirring for 10 min. After that, the solid part is filtered, and then dried to obtain the intermediate product A.

[0108] Take 3.4 g of PE-g-MAH (MAH grafting rate is 0.5%) and 150 mL of xylene, and then the temperature is increased to 110°C. The magnetic stirring speed is adjusted to 300 rpm for 1 h to obtain a homogeneous liquid. Then, nitrogen is introduced into the system. 6.2 g of the intermediate product A and 0.15 g of triphenylphosphine are added. After reaction for 3 h, the heating is stopped, and the system is naturally cooled to room temperature. After filtration and drying, the crystal seeds are obtained.

[0109] Take 250 g of calcined kaolin (1000 mesh), 8 g of crystal seeds and 35 g of sodium carbonate, grind them and then pass through a 1000 mesh sieve. 600 mL of deionized water is used for hydration. Then, a sodium silicate aqueous solution with a mass concentration of 25% is slowly added. The silicon-aluminum ratio is adjusted to 3.3. The mixture is stirred to obtain a mixed sol. Then, the system is transferred into a reaction kettle after being aged at room temperature for 15 h. The hydrothermal crystallization is carried out at 145°C for 16 h. Then, the solid part is filtered and placed in 50 mL of an impregnation liquid. The magnetic stirring speed is adjusted to 50 rpm for treatment for 20 min. Then, the system is filtered. The filter cake is treated with slow cold water flow for 1 min. After drying, the modified zeolite is obtained by crushing and passing through a 1000 mesh sieve.

[0110] The remaining steps are the same as those in Example 1.

[0111] Performance detection

[0112] 1. Apparent performance test

[0113] The apparent performance test of the modified hygroscopic composite membranes in Examples 1-4 and Comparative Examples 1-3 is carried out. The test items are shown in Table 1.

[0114] Table 1. Apparent performance test items of the modified hygroscopic composite membranes in Examples 1-4 and Comparative Examples 1-3

[0115]

[0116] The test results are shown in Table 2.

[0117] Table 2. Apparent performance test results of the modified moisture-absorbing composite films of Examples 1-4 and Comparative Examples 1-3

[0118]

[0119] Comparing Examples 1-4 and Comparative Examples 1-3 with Tables 1 and 2, it can be concluded that the absorbent membranes in the Examples 1-4 have intact surfaces without perforations or other defects. During the barrier performance test, the water vapor and oxygen permeability of the membranes remained at low levels. In contrast, Comparative Example 2, due to the addition of ABS-g-MAH treated modified zeolite to the membrane system, exhibited increased surface polarization of the zeolite and reduced compatibility with the PE base material. Perforations appeared in the melt-blown product after the modified zeolite was incorporated into the PE base material, resulting in a significant decrease in the barrier performance of the absorbent membrane in Comparative Example 2. Regarding the antibacterial properties of the membranes, the total aerobic bacteria count of the absorbent membranes in the Examples 1-4 was less than 1 cfu / 100 cm³. 2 The antibacterial properties are excellent. However, the antibacterial ability of the moisture-absorbing film prepared in Comparative Example 1 is slightly inferior to that of the Example scheme due to the limited ability of chelating divalent copper ions and divalent zinc ions to resist antibacterial metal ions during the seed preparation process. The microbial limits of Comparative Examples 2 and 3 are significantly increased compared to the Example scheme due to the influence of membrane integrity and effective antibacterial metal ion desorption, respectively. In all test groups, the modified moisture-absorbing PE film of the Example scheme can improve the storage time and effective life of the contents of the drug when applied to the pharmaceutical packaging film.

[0120] 2. Moisture absorption performance test

[0121] Take the modified PE films from Examples 1-4 and Comparative Examples 1-3, cut them into 10mm × 10mm samples, and after thorough drying, place them in an environment with a relative humidity of 75±2% and a temperature of 30℃ for 24 hours. Record the sample mass m0 and m1 before and after the test, respectively. Then, remove the test samples and place them at room temperature and ventilation for 120 minutes, recording the sample mass m2 at this time. According to the formula:

[0122] M = m1 - m0;

[0123] R = (m1 - m2) / M × 100%;

[0124] Where M: saturated moisture absorption capacity; R: residual moisture absorption rate.

[0125] Test results are as follows Figure 1 As shown.

[0126] Take Examples 1-4 and Comparative Examples 1-3 and combine them. Figure 1It can be concluded that the modified hygroscopic film saturation moisture absorption and residual moisture absorption rate shows a certain positive correlation trend in the test results, only from the saturated moisture absorption data of examples 1-4, within a certain range, with the increase of the amount of modified zeolite in PE base system, the moisture absorption performance of modified PE film prepared gradually improves; the comparative example 2 and the comparative example 3 due to the influence of the compatibility of modified zeolite and PE base system and the difference of zeolite preparation process, the modified PE film prepared after melt blending has slightly reduced hygroscopicity, while the carboxymethyl cellulose is used instead of polyethyleneimine in the comparative example 1, due to the difference of molecular weight and the influence of the degree of interaction with the crystal seed, the polarity of the modified zeolite prepared is slightly lower than that of the example scheme, which leads to the decrease of the moisture absorption capacity of the modified zeolite.

[0127] 3. Active metal ion desorption performance test

[0128] Take the modified PE film of examples 1-4 and comparative examples 1-3, cut into 10 pieces of 1 cm diameter test discs with a puncher, then take 5 pieces from each group and immerse them in an ethanol solution with a mass concentration of 10% (volume is V), adjust the magnetic stirring speed to 50 rpm for immersion treatment (40℃, 24h), then collect the leaching liquid and test the total ion concentration C of divalent copper ions and divalent zinc ions in the leaching liquid according to the test method of national standard GB / T7475-1987; mix the remaining 5 test discs of each group respectively, sinter in a tube furnace at 550℃ for 30 min, then take the sintered ash of each group and immerse it in 20 mL of 65% concentrated nitric acid and 2 mL of 10% hydrogen peroxide solution for 10 min, then calculate the total ion amount N of divalent copper ions and divalent zinc according to the test method of national standard GB / T7475-1987;

[0129] According to the formula: W=CV / N×100%;

[0130] The total desorption rate W of divalent copper ions and divalent zinc ions is calculated, and the results are shown in Figure 2 .

[0131] Take examples 1-4 and comparative examples 1-3 and combine Figure 2 It can be concluded that the divalent copper ion and divalent zinc ion leaching rate of the modified PE film of the example scheme is low, which can be maintained within 1.51‰, while the comparative examples 1-3 all have serious leaching problems; among them, the comparative example 3 uses the treatment method of "crystallization first and then loading" to load the antibacterial metal ions, and the divalent copper ions and divalent zinc ions appear obvious desorption phenomenon in the desorption test, which is not conducive to packaging drugs, and the precipitated ions reaching a certain dose may react with some active components in the drug and cause the decrease of drug activity; while the carboxymethyl cellulose used in the comparative example 1 is weaker than polyethyleneimine in chelating divalent copper ions and divalent zinc metal ions, which finally increases the amount of divalent copper ions and divalent zinc metal ions leaching from the PE film.

[0132] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified, or some of the technical features can be replaced by equivalent features, by those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a modified absorbent composite film, characterized by, The preparation steps include the following: According to the outside-in superposition sequence, the PET film, the Al foil and the modified PE film are coated and compounded, and then matured and dried to obtain the modified moisture absorption composite film; The preparation steps of the modified PE film include the following: Take the polyethylene master batch and the modified zeolite, mix, and then extrude and blow film to obtain the product; The preparation steps of the modified zeolite include the following: Take the calcined kaolin, the seed crystal and sodium carbonate, mix and grind, disperse with water, adjust the silicon-aluminum ratio to 3.3-3.5, place and age, and then perform the temperature rising crystallization treatment, and the product is broken and sieved after drying to obtain the modified zeolite; The seed crystal is obtained by microemulsion polymerization of methyl methacrylate, glycidyl methacrylate and polyethylene imine, and then grafting reaction of the polymerization product and PE-g-MAH is performed; The preparation steps of the seed crystal include the following: S01. Take methyl methacrylate, glycidyl methacrylate and an initiator, disperse at low speed to obtain a pre-dispersion liquid; S02. Take the emulsifier and polyethylene imine, mix and dissolve with water, then drop the pre-dispersion liquid, ultrasonic emulsify, heat and react, then perform demulsification, filtration, water washing, then place in an immersion liquid, filter again, dry to obtain the intermediate product A; S03. Take PE-g-MAH, add dimethylbenzene, heat and dissolve, then add the intermediate product A under nitrogen, catalyze and react, then cool and dry to obtain the seed crystal; In step S02, the preparation steps of the immersion liquid include the following: take zinc acetate and copper sulfate, disperse with water, drop ammonia water, stir, then add urea and continue to treat to obtain the immersion liquid; the ratio of zinc acetate, copper sulfate, ammonia water and urea is (0.5-0.8):(1.2-1.7):(1-2):(0.2-0.3).

2. The method of claim 1, wherein the modified absorbent composite film is prepared by the steps of: The coating composite operation, the sizing amount is controlled in 20±2g / m 2 .

3. The method of claim 1, wherein the modified absorbent composite film is prepared by the steps of: The mass ratio of the polyethylene master batch and the modified zeolite is (120-150):(5-8); the extrusion and blow film treatment is set to have a cylinder zone temperature of 150-165°C, a die temperature of 150-155°C and a blow ratio of (2-2.5):1; the thickness of the modified PE film is 50-55 microns.

4. The method of claim 1, wherein the modified absorbent composite film is prepared by the steps of: In the preparation process of the modified zeolite, the mass ratio of the calcined kaolin, the seed crystal and sodium carbonate is (40-60):(1-2):(6-8); The temperature rising crystallization treatment is adjusted to have a temperature of 120-150°C and a treatment time of 15-18h.

5. The method for preparing a modified moisture-absorbing composite membrane according to claim 1, characterized in that, In step S01, the mass ratio of methyl methacrylate, glycidyl methacrylate and the initiator is (7-7.5):(3.2-3.5):(0.1-0.2).

6. The method for preparing a modified moisture-absorbing composite membrane according to claim 1, characterized in that, In step S02, the temperature rising reaction is set to have a temperature of 60-65°C and a reaction time of 6-8h.

7. The method for preparing a modified moisture-absorbing composite membrane according to claim 1, characterized in that, In step S03, the catalyst used in the catalytic reaction is triphenylphosphine, the temperature is set to 110-120°C, and the reaction lasts for 3-5h.

8. A modified moisture absorption composite film prepared by the preparation method of any one of claims 1-7.

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