Environment-friendly recyclable medicine packaging composite film and preparation method thereof

Abstract

The invention relates to an environment-friendly recyclable medicine packaging composite film and a preparation method thereof, and belongs to the technical field of high polymer materials. According to the environment-friendly recoverable medicine packaging composite film, the vacuum aluminized biaxially oriented polypropylene film serves as the middle layer, the casting polypropylene film serves as the inner layer, the biaxially oriented polypropylene film serves as the outer layer, the environment-friendly recoverable medicine packaging composite film is obtained through layer-by-layer compounding, and the composite film is suitable for the fields of hot filling, retort pouches, sterile bags and the like. The environment-friendly recoverable medicine packaging composite film has good oxygen barrier performance, the shelf life of medicine can be prolonged, the environment-friendly concept that the single material is recoverable can be achieved due to the fact that the three layers of materials are all single polypropylene materials, the environment-friendly recoverable medicine packaging composite film can replace glass bottled traditional Chinese medicine oral liquid packaging to become a newly-developing packaging material in the oral liquid market, and the environment-friendly recoverable medicine packaging composite film is worthy of popularization and application. And batch production can be carried out.

Description

Technical Field

[0001] The invention relates to an environmentally friendly and recyclable composite film for drug packaging and a preparation method thereof, and belongs to the technical field of polymer materials. Background Art

[0002] For a long time, glass bottles have been the mainstream packaging form in the Chinese medicine oral liquid market. With its advantages of high transparency, good appearance, and stable product properties, it occupies a dominant position in the liquid medicine packaging market. However, there are also many inconveniences in the transportation and use links. It has the disadvantages of being fragile, difficult to administer, weak impact resistance, difficult to recycle, and high weight that increases transportation costs. In this context, the development of Chinese medicine oral liquid packaging materials and innovative packaging forms have become the main ways to solve the defects of Chinese medicine oral liquid in glass bottles. After long-term market research and comparison, composite packaging film has become an emerging packaging material in the Chinese medicine oral liquid market.

[0003] Chinese patent document CN118358230A discloses a high-drawing aluminum-plastic film and a processing method thereof, which includes, from the surface layer to the inner layer, a nylon protective layer, a composite aluminum foil layer and a three-layer co-extruded biaxially stretched polypropylene layer, wherein the nylon protective layer and the composite aluminum foil layer and the composite aluminum foil layer and the three-layer co-extruded biaxially stretched polypropylene layer are dry-compounded by a dry-type compounding machine; wherein the three-layer co-extruded biaxially stretched polypropylene layer is a three-layer co-extruded film prepared by co-extrusion casting, and includes an aluminum foil adhesive layer, a heat-resistant layer and a heat-sealing layer from the outside to the inside; the composite aluminum foil layer includes an aluminum layer and a polymer layer, and the outer surface of the polymer layer is formed with an aluminum layer by physical vapor deposition. The composite film prepared in this patent document contains heavy metal chromium salts and cannot be used for drug packaging, and uses a variety of types of polymer materials and cannot be simply recycled. Therefore, it is urgent to develop a recyclable composite film suitable for drug packaging. Summary of the invention

[0004] The purpose of the present invention is to provide an environmentally friendly and recyclable composite film for drug packaging and a preparation method thereof, so as to solve the problem that the current composite film materials are different and cannot be recycled.

[0005] The technical scheme of the environmentally friendly and recyclable drug packaging composite film of the present invention is as follows: An environmentally friendly and recyclable drug packaging composite film comprises a biaxially stretched polypropylene film, a vacuum aluminum-plated biaxially stretched polypropylene film and a cast polypropylene film which are sequentially composited; wherein the vacuum aluminum-plated biaxially stretched polypropylene film comprises a biaxially stretched polypropylene layer and a vacuum aluminum-plated layer, and the vacuum aluminum-plated biaxially stretched polypropylene film is composited with the biaxially stretched polypropylene film through the vacuum aluminum-plated layer; the cast polypropylene film comprises a transition layer, an adhesive layer and a heat-sealing layer which are composited in sequence, and the cast polypropylene film is composited with the biaxially stretched polypropylene layer of the vacuum aluminum-plated biaxially stretched polypropylene film through the transition layer; the transition layer is made of a transition layer material, which is homopolymerized polypropylene; the heat-sealing layer is made of a ternary copolymerized polypropylene, a heat-sealing agent, an anti-blocking agent and a lubricant; the adhesive layer is made of an adhesive layer material, which is made by melt extrusion granulation of maleic anhydride grafted polypropylene, epoxy group-modified nanoporous silica and epoxy group-modified nanofibrous wollastonite in a mass ratio of 100:2-3:4-5.

[0006] Preferably, the preparation method of the epoxy group-modified nanoporous silica is as follows: γ-glycidyloxypropyltrimethoxysilane, ethanol and water are mixed, the pH is adjusted to 3-4.5 with acid, nanoporous silica is added, and then heated to 70-80° C. and mixed for reaction for 7-10 hours.

[0007] Preferably, the mass ratio of the γ-glycidyloxypropyltrimethoxysilane to the nanoporous silica is 20-23:8-10.

[0008] Preferably, the preparation method of the epoxy group-modified nanofibrous wollastonite is as follows: nanofibrous wollastonite and γ-glycidyloxypropyltrimethoxysilane are mixed in ethanol at 60-70° C. for reaction for 2-4 hours.

[0009] Preferably, the mass ratio of the nanofibrous wollastonite to γ-glycidyloxypropyltrimethoxysilane is 80-100:10.

[0010] Preferably, the mass ratio of the terpolymer polypropylene, the heat sealant, the anti-blocking agent and the lubricant is 72:8:12:8.

[0011] Preferably, the heat sealant is propylene-butene copolymer.

[0012] Preferably, the lubricant is erucamide.

[0013] Preferably, the adhesive is silicon dioxide.

[0014] A method for preparing the above-mentioned environmentally friendly and recyclable composite film for drug packaging comprises the following steps: co-extruding a transition layer material, an adhesive layer material and a heat-sealing layer material to obtain a cast polypropylene film; then coating glue between the biaxially oriented polypropylene film and the vacuum aluminum-plated biaxially oriented polypropylene film, and then laminating to obtain a composite layer; finally coating glue between the composite layer and the cast polypropylene film, and then laminating to obtain an environmentally friendly and recyclable composite film for drug packaging.

[0015] The beneficial technical effects of the present invention are as follows: (1) The present invention uses epoxy group-modified nanoporous silica and epoxy group-modified nanofibrous wollastonite to modify maleic anhydride grafted polypropylene to obtain a bonding layer material, and chemically grafts the nanoporous silica and nanofibrous wollastonite onto the maleic anhydride grafted polypropylene molecular chain to ensure that the nanoporous silica and nanofibrous wollastonite are evenly and firmly attached to the maleic anhydride grafted polypropylene molecular chain; when the bonding layer material, the transition layer material and the heat-sealing layer material are melt-extruded into a co-extrusion die, part of the fibrous wollastonite in the bonding layer material can enter the transition layer interface, and part can enter the heat-sealing layer interface. At the same time, part of the resin molecular chains at the transition layer interface can enter the pores of the porous silica under the extrusion effect, and part of the resin molecular chains at the heat-sealing layer interface can enter the pores of the porous silica under the extrusion effect. Therefore, the bonding layer, transition layer and heat-sealing layer are tightly combined through the entanglement of polymer chains in the bonding layer, the transition connection of fibrous wollastonite and the porous adsorption of porous silica, thereby improving the adhesion between the transition layer and the heat-sealing layer.

[0016] (2) The cast polypropylene film prepared by the above-mentioned adhesive layer, transition layer and heat-sealing layer contains a certain amount of nanoparticles, which can effectively improve the heat resistance of the cast polypropylene film and ensure that the packaged drugs are not damaged when heated. In addition, the transition connection effect of the fibrous wollastonite and the porous adsorption effect of the porous silica can effectively improve the density of the resin matrix, thereby improving the barrier properties of the composite film.

[0017] (3) The present invention uses a vacuum aluminum-plated biaxially oriented polypropylene film as the middle layer, a cast polypropylene film as the inner layer, and a biaxially oriented polypropylene film as the outer layer, and obtains an environmentally friendly and recyclable composite film for drug packaging by laminating layer by layer. The composite film of the present invention is portable, has good water and oxygen barriers, and has good aroma retention properties. It has high mechanical strength, and its pressure resistance and transportability are superior to those of glass bottles. The material structure fully meets customer needs. According to market feedback, the test samples have achieved the expected results in terms of breakage rate, shelf life, convenient processing and transportation, and single material recyclability. The composite film of the present invention is suitable for hot filling, retort bags, aseptic bags and other fields. The environmentally friendly and recyclable composite film for drug packaging of the present invention has good oxygen barrier properties and can extend the shelf life of drugs. The composite film of the present invention was measured by a water vapor permeability meter and a gas permeability meter, and the water vapor and oxygen barrier rates of the composite film of the present invention were both less than The barrier performance of this combined material can achieve the effect of an aluminum foil structure, and the three layers are all single-material PP, which are environmentally friendly and recyclable materials. This single-material recyclable packaging composite film has high mechanical strength, good pressure resistance, convenient transportation, and portability. It has good water-blocking, oxygen-blocking, and fragrance-preserving properties, and can better maintain the stability of drugs. After small and medium tests, this preparation method can realize the environmental protection concept of single-material recyclability and replace glass bottled Chinese medicine oral liquid packaging to become a new packaging material in the oral liquid market, and can be mass-produced.

[0018] (4) Compared with oral liquids in glass bottles, Chinese medicine oral liquid strip packs have the advantages of being environmentally friendly and recyclable, having a short production process, being light in weight and having low transportation costs, being green and environmentally friendly, not easy to break, having strong impact resistance, having high safety performance, and being easy to carry. They are expected to replace the mainstream form of Chinese medicine oral liquid packaging in glass bottles in the market, and the industry has huge room for development. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the water vapor and oxygen barrier rate test results of the environmentally friendly recyclable pharmaceutical packaging composite films of each comparative example; Figure 2 Schematic diagram of peel strength between the transition layer and the heat-sealing layer in the cast polypropylene film of the environmentally friendly and recyclable drug packaging composite film of each comparative example; Figure 3 Schematic diagram of the heat-sealing strength between the transition layer and the heat-sealing layer in the cast polypropylene film of the environmentally friendly and recyclable drug packaging composite film of each comparative example. DETAILED DESCRIPTION

[0020] The following examples are intended to further illustrate the present invention rather than to limit the scope of protection of the present invention.

[0021] Example 1

[0022] The environmentally friendly and recyclable drug packaging composite film of this embodiment includes a biaxially oriented polypropylene film (BOPP), a vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) and a cast polypropylene film (CPP) which are sequentially composited up and down; wherein the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) includes a biaxially oriented polypropylene layer and a vacuum aluminum-plated layer, and the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) is composited with the biaxially oriented polypropylene film (BOPP) through the vacuum aluminum-plated layer; the cast polypropylene film (CPP) includes a transition layer, an adhesive layer and a heat-sealing layer composited in sequence, and the cast polypropylene film (CPP) is composited with the vacuum aluminum-plated biaxially oriented polypropylene film (BOPP) through the transition layer. The biaxially oriented polypropylene layers of VMBOPP are compounded together; the thickness of biaxially oriented polypropylene film (BOPP) is 18μm, and it can withstand high-temperature cooking at 121°C; the thickness of vacuum aluminized biaxially oriented polypropylene film (VMBOPP) is 18μm, which is a vacuum aluminized packaging film based on BOPP. It is a soft packaging material with excellent metallic luster and barrier properties. It has high barrier properties to water vapor and oxygen, and is a recyclable single-material packaging that can be obtained commercially or customized; the thickness of cast polypropylene film is 40μm, which has the characteristics of good gloss, softness and easy tearing, strong moisture and oxygen barrier properties, excellent heat resistance, and easy heat sealing.

[0023] The method for preparing the environmentally friendly and recyclable drug packaging composite film of this embodiment comprises the following steps: (1) Add 20 g of γ-glycidyloxypropyltrimethoxysilane, 100 mL of anhydrous ethanol and 10 mL of deionized water into a flask, then add hydrochloric acid into the flask to adjust the pH of the material in the flask to 3, then add 8 g of nanoporous silica into the flask under stirring, then heat the material in the flask to 70°C, stir and reflux for 7 h, filter, and wash the filter cake with ethanol to obtain epoxy group-modified nanoporous silica.

[0024] (2) 80 g of nanofibrous wollastonite and 10 g of γ-glycidyloxypropyltrimethoxysilane were added to 900 g of anhydrous ethanol, heated to 60° C. and stirred for reaction for 2 h. After the reaction was completed, the mixture was filtered, and the filter cake was rinsed with ethanol and dried to obtain epoxy group-modified nanofibrous wollastonite.

[0025] (3) Maleic anhydride grafted polypropylene, epoxy group modified nanoporous silica and epoxy group modified nanofibrous wollastonite in a mass ratio of 100:2:4 are melt-extruded and granulated to obtain a bonding layer material.

[0026] (4) The transition layer material (homopolymer polypropylene for cast film), the bonding layer material and the heat sealing layer material (the heat sealing layer material is composed of terpolymer polypropylene for cast film, a heat sealing agent, an anti-blocking agent and a lubricant in a mass ratio of 72:8:12:8, the heat sealing agent is propylene-butene copolymer, the lubricant is erucic acid amide, and the adhesive is silicon dioxide) are respectively placed into three extruders of a three-layer co-extrusion film unit. Each extruder heats and melt-extrudes the internal material to the co-extrusion die head, and then blows and air-cools to obtain an inner layer cast polypropylene film; wherein the melt extrusion temperature of the barrier layer material is 210°C to 220°C, the melt extrusion temperature of the bonding layer material is 150°C to 170°C, and the melt extrusion temperature of the heat sealing layer material is 190°C to 200°C.

[0027] (5) Coat solvent-free polyurethane two-component glue (the amount of glue is ), and then composite curing is performed at 45°C to obtain a composite layer. The solvent-free polyurethane two-component glue includes a polyester polyol material and a polyurethane curing agent, which are mixed in a mass ratio of 1:1 when used.

[0028] The preparation method of the polyester polyol material is as follows: 65g of poly (neopentyl adipate) (molecular weight 2500), 30g of poly (1,4-butylene adipate) (molecular weight 1000) and 22g of neopentyl glycol are added to a reaction container, heated to 120°C, vacuumed for dehydration, and then 1.2g of an adhesion modifier is added and stirred evenly to obtain a polyester polyol material; the preparation method of the adhesion modifier is as follows: at 0°C, a chloroform solution of diethylphosphonium chloride (mass fraction 20%) is added dropwise. Add to the chloroform solution of 2,2,2-triaminotriethylamine (mass fraction is 40%, the molar ratio of diethylphosphine chloride and 2,2,2-triaminotriethylamine is 1:1), stir and react for 5 hours after the addition is completed, and then continue to add the chloroform solution of triethoxychlorosilane (mass fraction is 20%, the molar ratio of triethoxychlorosilane and 2,2,2-triaminotriethylamine is 1:1), continue to stir and react for 6 hours after the addition is completed, filter, and distill the filtrate under reduced pressure to remove chloroform to obtain an adhesion modifier.

[0029] The preparation method of the polyurethane curing agent is as follows: 45 g of polyoxypropylene glycol (molecular weight 2500) is added to a reaction container, heated to 120°C, vacuumed for dehydration, then cooled to 60°C, 60 g of 4,4-diphenylmethane diisocyanate and 0.5 g of 2-aminoethylphosphonic acid are added, heated to 80°C, stirred for reaction for 2 hours, and a polyurethane curing agent is obtained.

[0030] (4) Glue is coated between the composite layer and the cast polypropylene film (CPP), and then the composite layer and the cast polypropylene film (CPP) are laminated by a dry laminating machine to obtain an environmentally friendly and recyclable composite film for drug packaging.

[0031] Example 2

[0032] The environmentally friendly and recyclable drug packaging composite film of this embodiment includes a biaxially oriented polypropylene film (BOPP), a vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) and a cast polypropylene film (CPP) which are sequentially composited up and down; wherein the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) includes a biaxially oriented polypropylene layer and a vacuum aluminum-plated layer, and the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) is composited with the biaxially oriented polypropylene film (BOPP) through the vacuum aluminum-plated layer; the cast polypropylene film (CPP) includes a transition layer, an adhesive layer and a heat-sealing layer composited in sequence, and the cast polypropylene film (CPP) is composited with the vacuum aluminum-plated biaxially oriented polypropylene film (BOPP) through the transition layer. The biaxially oriented polypropylene layers of the VMBOPP are compounded together; the thickness of the biaxially oriented polypropylene film (BOPP) is 15μm, and it can withstand high-temperature cooking at 121°C; the thickness of the vacuum aluminized biaxially oriented polypropylene film (VMBOPP) is 18μm, which is a vacuum aluminized packaging film based on BOPP. It is a soft packaging material with excellent metallic luster and barrier properties. It has high barrier properties to water vapor and oxygen, and is a recyclable single-material packaging that can be obtained commercially or customized; the thickness of the cast polypropylene film is 80μm, and the material has the characteristics of good gloss, softness and easy tearing, strong moisture and oxygen barrier properties, excellent heat resistance, and easy heat sealing.

[0033] The method for preparing the environmentally friendly and recyclable drug packaging composite film of this embodiment comprises the following steps: (1) Add 23 g of γ-glycidyloxypropyltrimethoxysilane, 120 mL of anhydrous ethanol and 13 mL of deionized water into a flask, then add hydrochloric acid into the flask to adjust the pH of the material in the flask to 4.5, then add 10 g of nanoporous silica into the flask under stirring, then heat the material in the flask to 70-80 ° C, stir and reflux for 10 h, filter, and wash the filter cake with ethanol to obtain epoxy group-modified nanoporous silica.

[0034] (2) 100 g of nanofibrous wollastonite and 10 g of γ-glycidyloxypropyltrimethoxysilane were added to 1000 g of anhydrous ethanol, heated to 70° C. and stirred for reaction for 4 h. After the reaction was completed, the mixture was filtered, and the filter cake was rinsed with ethanol and dried to obtain epoxy group-modified nanofibrous wollastonite.

[0035] (3) Maleic anhydride grafted polypropylene, epoxy group modified nanoporous silica and epoxy group modified nanofibrous wollastonite in a mass ratio of 100:3:5 are melt-extruded and granulated to obtain a bonding layer material.

[0036] (4) The transition layer material (homopolymer polypropylene for cast film), the bonding layer material and the heat sealing layer material (the heat sealing layer material is composed of terpolymer polypropylene for cast film, a heat sealing agent, an anti-blocking agent and a lubricant in a mass ratio of 72:8:12:8, the heat sealing agent is propylene-butene copolymer, the lubricant is erucic acid amide, and the adhesive is silicon dioxide) are respectively placed into three extruders of a three-layer co-extrusion film unit. Each extruder heats and melt-extrudes the internal material to the co-extrusion die head, and then blows and air-cools to obtain an inner layer cast polypropylene film; wherein the melt extrusion temperature of the barrier layer material is 210°C to 220°C, the melt extrusion temperature of the bonding layer material is 150°C to 170°C, and the melt extrusion temperature of the heat sealing layer material is 190°C to 200°C.

[0037] (5) Coat solvent-free polyurethane two-component glue (the amount of glue is ), and then composite curing is performed at 45°C to obtain a composite layer. The solvent-free polyurethane two-component glue includes a polyester polyol material and a polyurethane curing agent, which are mixed in a mass ratio of 1:1 when used.

[0038] The preparation method of the polyester polyol material is as follows: 65g of poly (neopentyl adipate) (molecular weight 2500), 30g of poly (1,4-butylene adipate) (molecular weight 1000) and 22g of neopentyl glycol are added to a reaction container, heated to 120°C, vacuumed for dehydration, and then 1.2g of an adhesion modifier is added and stirred evenly to obtain a polyester polyol material; the preparation method of the adhesion modifier is as follows: at 0°C, a chloroform solution of diethylphosphonium chloride (mass fraction 20%) is added dropwise. Add to the chloroform solution of 2,2,2-triaminotriethylamine (mass fraction is 40%, the molar ratio of diethylphosphine chloride and 2,2,2-triaminotriethylamine is 1:1), stir and react for 5 hours after the addition is completed, and then continue to add the chloroform solution of triethoxychlorosilane (mass fraction is 20%, the molar ratio of triethoxychlorosilane and 2,2,2-triaminotriethylamine is 1:1), continue to stir and react for 6 hours after the addition is completed, filter, and distill the filtrate under reduced pressure to remove chloroform to obtain an adhesion modifier.

[0039] The preparation method of the polyurethane curing agent is as follows: 45 g of polyoxypropylene glycol (molecular weight 2500) is added to a reaction container, heated to 120°C, vacuumed for dehydration, then cooled to 60°C, 60 g of 4,4-diphenylmethane diisocyanate and 0.5 g of 2-aminoethylphosphonic acid are added, heated to 80°C, stirred for reaction for 2 hours, and a polyurethane curing agent is obtained.

[0040] (4) Glue is coated between the composite layer and the cast polypropylene film (CPP), and then the composite layer and the cast polypropylene film (CPP) are laminated by a dry laminating machine to obtain an environmentally friendly and recyclable composite film for drug packaging.

[0041] Example 3

[0042] The environmentally friendly and recyclable drug packaging composite film of this embodiment includes a biaxially oriented polypropylene film (BOPP), a vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) and a cast polypropylene film (CPP) which are sequentially composited up and down; wherein the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) includes a biaxially oriented polypropylene layer and a vacuum aluminum-plated layer, and the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) is composited with the biaxially oriented polypropylene film (BOPP) through the vacuum aluminum-plated layer; the cast polypropylene film (CPP) includes a transition layer, an adhesive layer and a heat-sealing layer composited in sequence, and the cast polypropylene film (CPP) is composited with the vacuum aluminum-plated biaxially oriented polypropylene film (BOPP) through the transition layer. The biaxially oriented polypropylene layer of VMBOPP is compounded together; the thickness of biaxially oriented polypropylene film (BOPP) is 16μm, which can withstand high temperature cooking at 121℃; the thickness of vacuum aluminized biaxially oriented polypropylene film (VMBOPP) is 18μm, which is a vacuum aluminized packaging film based on BOPP, and is a soft packaging material with excellent metallic luster and barrier properties. It has high barrier properties to water vapor and oxygen, and is a recyclable single-material packaging that can be obtained commercially or customized; the thickness of cast polypropylene film is 60μm, which has the characteristics of good gloss, softness and easy tearing, strong moisture and oxygen barrier properties, excellent heat resistance, and easy heat sealing.

[0043] The method for preparing the environmentally friendly and recyclable drug packaging composite film of this embodiment comprises the following steps: (1) Add 22 g of γ-glycidyloxypropyltrimethoxysilane, 110 mL of anhydrous ethanol and 12 mL of deionized water into a flask, then add hydrochloric acid into the flask to adjust the pH of the material in the flask to 4, then add 9 g of nanoporous silica into the flask under stirring, then heat the material in the flask to 75°C, stir and reflux for 8 h, filter, and wash the filter cake with ethanol to obtain epoxy group-modified nanoporous silica.

[0044] (2) 90 g of nanofibrous wollastonite and 10 g of γ-glycidyloxypropyltrimethoxysilane were added to 950 g of anhydrous ethanol, heated to 65° C. and stirred for reaction for 3 h. After the reaction was completed, the mixture was filtered, and the filter cake was rinsed with ethanol and dried to obtain epoxy group-modified nanofibrous wollastonite.

[0045] (3) Maleic anhydride grafted polypropylene, epoxy group modified nanoporous silica and epoxy group modified nanofibrous wollastonite in a mass ratio of 100:2.5:4.5 are melt-extruded and granulated to obtain a bonding layer material.

[0046] (4) The transition layer material (homopolymer polypropylene for cast film), the bonding layer material and the heat sealing layer material (the heat sealing layer material is composed of terpolymer polypropylene for cast film, a heat sealing agent, an anti-blocking agent and a lubricant in a mass ratio of 72:8:12:8, the heat sealing agent is propylene-butene copolymer, the lubricant is erucic acid amide, and the adhesive is silicon dioxide) are respectively placed into three extruders of a three-layer co-extrusion film unit. Each extruder heats and melt-extrudes the internal material to the co-extrusion die head, and then blows and air-cools to obtain an inner layer cast polypropylene film; wherein the melt extrusion temperature of the barrier layer material is 210°C to 220°C, the melt extrusion temperature of the bonding layer material is 150°C to 170°C, and the melt extrusion temperature of the heat sealing layer material is 190°C to 200°C.

[0047] (5) Coat solvent-free polyurethane two-component glue (the amount of glue is ), and then composite curing is performed at 45°C to obtain a composite layer. The solvent-free polyurethane two-component glue includes a polyester polyol material and a polyurethane curing agent, which are mixed in a mass ratio of 1:1 when used.

[0048] The preparation method of the polyester polyol material is as follows: 65g of poly (neopentyl adipate) (molecular weight 2500), 30g of poly (1,4-butylene adipate) (molecular weight 1000) and 22g of neopentyl glycol are added to a reaction container, heated to 120°C, vacuumed for dehydration, and then 1.2g of an adhesion modifier is added and stirred evenly to obtain a polyester polyol material; the preparation method of the adhesion modifier is as follows: at 0°C, a chloroform solution of diethylphosphonium chloride (mass fraction 20%) is added dropwise. Add to the chloroform solution of 2,2,2-triaminotriethylamine (mass fraction is 40%, the molar ratio of diethylphosphine chloride and 2,2,2-triaminotriethylamine is 1:1), stir and react for 5 hours after the addition is completed, and then continue to add the chloroform solution of triethoxychlorosilane (mass fraction is 20%, the molar ratio of triethoxychlorosilane and 2,2,2-triaminotriethylamine is 1:1), continue to stir and react for 6 hours after the addition is completed, filter, and distill the filtrate under reduced pressure to remove chloroform to obtain an adhesion modifier.

[0049] The preparation method of the polyurethane curing agent is as follows: 45 g of polyoxypropylene glycol (molecular weight 2500) is added to a reaction container, heated to 120°C, vacuumed for dehydration, then cooled to 60°C, 60 g of 4,4-diphenylmethane diisocyanate and 0.5 g of 2-aminoethylphosphonic acid are added, heated to 80°C, stirred for reaction for 2 hours, and a polyurethane curing agent is obtained.

[0050] (4) Glue is coated between the composite layer and the cast polypropylene film (CPP), and then the composite layer and the cast polypropylene film (CPP) are laminated by a dry laminating machine to obtain an environmentally friendly and recyclable composite film for drug packaging.

[0051] Comparative Example 1 The only difference between the environmentally friendly recyclable drug packaging composite film of this comparative example and the environmentally friendly recyclable drug packaging composite film of Example 1 is that the bonding layer material used in the environmentally friendly recyclable drug packaging composite film of this comparative example is obtained by melt extrusion granulation of maleic anhydride grafted polypropylene, nanoporous silica and nanofibrous wollastonite in a mass ratio of 100:2:4.

[0052] Comparative Example 2 The only difference between the environmentally friendly recyclable drug packaging composite film of this comparative example and the environmentally friendly recyclable drug packaging composite film of Example 1 is that the bonding layer material used in the environmentally friendly recyclable drug packaging composite film of this comparative example is obtained by melt extrusion granulation of maleic anhydride grafted polypropylene and epoxy group modified nanoporous silica in a mass ratio of 100:6.

[0053] Comparative Example 3 The only difference between the environmentally friendly recyclable drug packaging composite film of this comparative example and the environmentally friendly recyclable drug packaging composite film of Example 1 is that the bonding layer material used in the environmentally friendly recyclable drug packaging composite film of this comparative example is obtained by melt extrusion granulation of maleic anhydride grafted polypropylene and epoxy group modified nanofibrous wollastonite in a mass ratio of 100:6.

[0054] Comparative Example 4 The only difference between the environmentally friendly recyclable drug packaging composite film of this comparative example and the environmentally friendly recyclable drug packaging composite film of Example 1 is that the bonding layer material used in the environmentally friendly recyclable drug packaging composite film of this comparative example is obtained by melt extrusion granulation of maleic anhydride grafted polypropylene, epoxy group modified nano-silica (nano-silica without porous structure) and epoxy group modified nano-fibrous wollastonite in a mass ratio of 100:2:4.

[0055] Comparative Example 5 The only difference between the environmentally friendly recyclable drug packaging composite film of this comparative example and the environmentally friendly recyclable drug packaging composite film of Example 1 is that the bonding layer material used in the environmentally friendly recyclable drug packaging composite film of this comparative example is obtained by melt extrusion granulation of maleic anhydride grafted polypropylene, epoxy group modified nanoporous silica and epoxy group modified nano flaky wollastonite in a mass ratio of 100:2:4.

[0056] Effect Example 1 In order to evaluate the application effect of the environmentally friendly recyclable drug packaging composite films of each embodiment and comparative example in drug packaging, the water vapor and oxygen barrier rates of the environmentally friendly recyclable drug packaging composite films of each embodiment and comparative example were measured using a water vapor permeability tester and a gas permeability tester, respectively, and the results are shown in Table 1. At the same time, the peel strength between the transition layer and the heat seal layer in the cast polypropylene film was tested according to the method in the standard YBB00102003-2015 "Peel Strength Determination Method", and the heat seal strength of the heat seal layer in the cast polypropylene film was tested according to the method in the standard YBB00122003-2015 "Heat Seal Strength Determination Method", and the results are shown in Table 1, Figure 1-3 shown.

[0057] Table 1 Water vapor and oxygen barrier rates of the environmentally friendly recyclable drug packaging composite films of various embodiments and comparative examples, peel strength between the transition layer and the heat seal layer in the cast polypropylene film, and heat seal strength

[0058] According to Table 1, the water vapor and oxygen barrier rates of the environmentally friendly recyclable drug packaging composite film of the present invention are relatively high, and the peel strength and heat sealing strength between the transition layer and the heat sealing layer in the cast polypropylene film are relatively high. The environmentally friendly recyclable drug packaging composite film of the present invention has high mechanical strength, good pressure resistance, convenient transportation, and portability, and has good water-blocking, oxygen-blocking, and fragrance-preserving properties, and can better maintain the stability of drugs.

[0059] Effect Example 2 In order to investigate the bonding effect of solvent-free polyurethane two-component glues prepared with different polyester alcohols and different adhesion modifiers on biaxially oriented polypropylene film (BOPP) and vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP), the test was repeated according to step (5) of Example 1, except that the poly(neopentyl adipate) used in preparing the polyester polyol material was replaced by poly(diethylene adipate) of equal molecular weight, or the 2,2,2-triaminotriethylamine used in preparing the adhesion modifier was replaced by 1,4-butylene diamine, or the 2-aminoethylphosphonic acid used in preparing the polyurethane curing agent was replaced by phosphoric acid. Then, the prepared solvent-free polyurethane two-component glue was coated between the biaxially oriented polypropylene film (BOPP) and the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) and then compounded. After the glue was cured, the peel strength between the biaxially oriented polypropylene film (BOPP) and the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) was tested, and whether aluminum transfer occurred was observed. The test results are shown in Table 2. Among them, the solvent-free polyurethane two-component glue prepared by replacing poly(neopentyl adipate) with poly(diethylene adipate) of equal molecular weight was named glue A, the solvent-free polyurethane two-component glue prepared by replacing 2,2,2-triaminotriethylamine with 1,4-butanediamine was named glue B, the solvent-free polyurethane two-component glue prepared by replacing 2-aminoethylphosphonic acid with phosphoric acid was named glue C, and the solvent-free polyurethane two-component glue prepared in Example 1 was named glue D.

[0060] Table 2 Bonding effect of different solvent-free polyurethane two-component glues

[0061] As can be seen from Table 2, by introducing phosphate ester and siloxane into small molecule active amino compounds as adhesion modifiers, and introducing 2-aminoethylphosphonic acid as an active monomer into the curing agent, the prepared solvent-free polyurethane two-component glue can make the biaxially oriented polypropylene film (BOPP) and the vacuum aluminum-plated biaxially oriented polypropylene film (VMBOPP) have a higher bonding strength, and at the same time can make the product appearance optimal, avoid aluminum transfer, and ensure the water barrier, oxygen barrier, and fragrance retention properties of the composite film.

Claims

1. An environmentally friendly and recyclable composite film for drug packaging, characterized in that: The invention comprises a biaxially stretched polypropylene film, a vacuum aluminum-plated biaxially stretched polypropylene film and a cast polypropylene film which are compositely arranged in sequence; wherein the vacuum aluminum-plated biaxially stretched polypropylene film comprises a biaxially stretched polypropylene layer and a vacuum aluminum-plated layer, and the vacuum aluminum-plated biaxially stretched polypropylene film is composited with the biaxially stretched polypropylene film through the vacuum aluminum-plated layer; the cast polypropylene film comprises a transition layer, an adhesive layer and a heat-sealing layer which are composited in sequence, and the cast polypropylene film is composited with the biaxially stretched polypropylene layer of the vacuum aluminum-plated biaxially stretched polypropylene film through the transition layer; the transition layer is made of a transition layer material, which is homopolymerized polypropylene; the heat-sealing layer is made of a ternary copolymerized polypropylene, a heat-sealing agent, an anti-adhesive agent and a lubricant; the adhesive layer is made of an adhesive layer material, which is made of maleic anhydride grafted polypropylene, epoxy group-modified nanoporous silica and epoxy group-modified nanofibrous wollastonite in a mass ratio of 100:2-3:4-5 by melt extrusion granulation.

2. The environmentally friendly and recyclable drug packaging composite film according to claim 1, characterized in that: The preparation method of the epoxy group-modified nanoporous silica is as follows: γ-glycidyloxypropyltrimethoxysilane, ethanol and water are mixed, the pH is adjusted to 3-4.5 with acid, the nanoporous silica is added, and then heated to 70-80° C. and mixed for reaction for 7-10 hours.

3. The environmentally friendly and recyclable drug packaging composite film according to claim 2, characterized in that: The mass ratio of the γ-glycidyloxypropyltrimethoxysilane to the nanoporous silica is 20-23:8-10.

4. The environmentally friendly and recyclable drug packaging composite film according to claim 1, characterized in that: The preparation method of the epoxy group-modified nanofibrous wollastonite is as follows: nanofibrous wollastonite and γ-glycidyloxypropyltrimethoxysilane are mixed in ethanol at 60-70° C. for reaction for 2-4 hours.

5. The environmentally friendly and recyclable composite film for drug packaging according to claim 4, characterized in that: The mass ratio of the nanofibrous wollastonite to γ-glycidyloxypropyltrimethoxysilane is 80-100:

10.

6. The environmentally friendly and recyclable composite film for drug packaging according to claim 1, characterized in that: The mass ratio of the terpolymer polypropylene, the heat sealant, the anti-blocking agent and the lubricant is 72:8:12:

8.

7. The environmentally friendly and recyclable composite film for drug packaging according to claim 6, characterized in that: The heat sealant is propylene-butene copolymer.

8. The environmentally friendly and recyclable composite film for drug packaging according to claim 6, characterized in that: The lubricant is erucamide.

9. The environmentally friendly and recyclable composite film for drug packaging according to claim 6, characterized in that: The adhesive is silicon dioxide.

10. A method for preparing an environmentally friendly and recyclable composite film for drug packaging as claimed in claim 1, characterized in that: The method comprises the following steps: co-extruding a transition layer material, an adhesive layer material and a heat-sealing layer material to obtain a cast polypropylene film; coating glue between the biaxially oriented polypropylene film and the vacuum aluminum-plated biaxially oriented polypropylene film, and then laminating to obtain a composite layer; and finally coating glue between the composite layer and the cast polypropylene film, and then laminating to obtain an environmentally friendly and recyclable composite film for drug packaging.

Images