A medicine packaging composite film with super peel strength

Abstract

The peeling strength of the composite film aluminized polyester layer and polyethylene layer is low and decays greatly, and delamination often occurs in the use and product sales process of the broad masses. In order to solve this problem, the patent introduces nano aluminum into the reinforcing layer to synthesize nano master batch, uses the nano master batch containing nano aluminum as the raw material of the reinforcing layer, adds freeze-dried graphene oxide powder to modify the tackifying resin applied in the bonding layer, and the synergistic effect of the nano master batch and the freeze-dried graphene oxide powder modified tackifying resin makes the prepared medicine packaging composite film have high peeling strength. The purpose of the patent is to provide a medicine packaging composite film with super strong peeling strength.

Description

Technical Field

[0001] This invention relates to a pharmaceutical packaging, and more particularly to a pharmaceutical packaging composite film with ultra-high peel strength. Background Technology

[0002] Because drugs are in contact with their packaging materials for an extended period, spanning the entire shelf life of the drug, the biosafety of packaging materials should be given the same level of importance as the safety of the drug itself. Currently, the vast majority of commercially available drug packaging in China primarily fulfills its basic function of protecting the drug, neglecting other aspects, particularly its role in facilitating use and improving medication safety—a reflection of humanistic care for patients and their families. This neglect is precisely a crucial indicator of social progress in the pharmaceutical industry. Therefore, drug packaging materials are an indispensable part of pharmaceuticals. Using safe packaging materials ensures the protection of drugs during transportation and storage, isolating them from the external environment as much as possible and preventing deterioration or loss of efficacy. Only by selecting compliant packaging materials and appropriate packaging methods can the quality of drugs be effectively and safely guaranteed, allowing the public to purchase and use medications with confidence.

[0003] Most pharmaceutical packaging composite films on the market are made of three layers: a polyester layer, an aluminized polyester layer / aluminum foil layer, and a polyethylene layer, connected by adhesives. However, currently available pharmaceutical flexible packaging films often experience aluminum breakage at the sealing edges and air leakage at the heat seal during pharmaceutical manufacturing. Special packaging products frequently suffer from seal breakage, aluminum breakage, air leakage, and poor sealing, affecting the barrier performance of the packaging film. Common problems with the three-layer aluminized structure include low composite strength between the PE substrate and the aluminized polyester film, leading to delamination during product distribution and affecting the product's barrier performance. Additionally, heat-sealing delamination and poor sealing are prone to occur during pharmaceutical packaging manufacturing. Powdered drugs experience electrostatic adsorption during packaging, resulting in a large amount of powder residue on the inner wall of the film, causing drug waste during user use. Furthermore, the powder residue on the inner wall of the film can also affect the sealing strength of the bag during production.

[0004] To address the above issues, this patent optimizes the process of synthetic polyethylene substrate, increasing the peel strength between the polyethylene substrate and aluminum foil or polyester aluminized film. This reduces aluminum foil breakage and air leakage at the heat-sealing point of three-layer aluminum foil products. For back-sealed products, the heat-sealing performance at the back seal is improved, reducing the risk of air leakage and breakage. It also solves the problem of powder adhering to the wall due to static electricity in composite films. Summary of the Invention

[0005] The peel strength between the aluminized polyester layer and the polyethylene layer of the composite film is low and attenuates significantly, often resulting in delamination during use and sales. To address this issue, this patent aims to propose a pharmaceutical packaging composite film with superior peel strength to improve the peel strength between the drug and its packaging.

[0006] This invention provides the following technical solution:

[0007] S1. Preparation of the corona layer: Weigh 30-60% high-density polyethylene, 20-40% linear low-density polyethylene, 10% polytetrafluoroethylene, and 5% methyl silicone oil according to the mass ratio. Then, place the high-density polyethylene and linear low-density polyethylene in a mixer, start the machine, add methyl silicone oil to wet the surfaces of the high-density polyethylene and linear low-density polyethylene, and then add polytetrafluoroethylene to make the polytetrafluoroethylene completely adhere to the surfaces of the high-density polyethylene and linear low-density polyethylene. Subsequently, the above mixture is granulated into nanoparticles using a twin-screw granulator.

[0008] S2. Preparation of the reinforcing layer: First, 35% nano-Al, 25% nano-TiO2, 15% nano-SiO2, and 25% nano-attapulgite were weighed according to the following mass ratio. After high-speed mixing for ten minutes, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanocomposite particles. Then, 20% nanocomposite particles, 46% low-density polyethylene, 22% linear low-density polyethylene, 9% ethylene bis-stearamide, 1% polytetrafluoroethylene, and 2% methoxysilane coupling agent were weighed according to the following mass ratio. After high-speed mixing for half an hour, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanomasterbatch. Finally, 85% nanomasterbatch, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio. These were mixed using a mixer and then granulated using a twin-screw extruder to form nanoparticles.

[0009] S3. Preparation of heat-sealing layer: Weigh 50% metallocene polyethylene, 10% fluorinated ethylene propylene copolymer, 5% methyl silicone oil and 35% aluminum strip according to the mass ratio, mix them with a mixer and then form nanoparticles using a twin-screw granulator.

[0010] S4. Preparation of the adhesive layer: First, the tackifying resin was modified. 4 g of dehydrated hydroxyl-terminated butadiene-acrylonitrile rubber was dissolved in 20 mL of N,N-dimethylformamide, followed by the addition of 0.1-1 g of lyophilized graphene oxide powder and ultrasonic treatment for 1 h to obtain an N,N-dimethylformamide solution of graphene-based toughening agent. Then, 20 g of epoxy resin was added, and after reaction, the modified tackifying resin was obtained. 50-70% polyethylene-methyl methacrylate, 20-30% modified tackifying resin, 10% fluorinated ethylene-propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio, mixed in a mixer, and then granulated into nanoparticles using a twin-screw extruder.

[0011] S5. Preparation of the four-layer co-extruded film: The nanoparticles in S1-S4 are sequentially processed into a composite film with a thickness of 0.1 mm using a four-layer co-extruded casting film production unit, consisting of a corona layer, a reinforcing layer, a heat-sealing layer, and an adhesive layer. Then, a 3-5 μm thick ethylene-acrylic acid copolymer coating is applied to the outer layer of the four-layer co-extruded film using an extruder. The outer layer of the co-extruded film needs to be corona treated to improve the adhesion and peel strength between the outer layer and the ethylene-acrylic acid copolymer coating.

[0012] Preferably, the organic reagents used in this invention are all reagents with a purity of 90% or higher.

[0013] The pharmaceutical packaging composite film of the present invention uses a four-layer aluminum foil product, which adds an extra reinforcing layer compared with the existing three-layer aluminum foil product.

[0014] The present invention introduces nano-Al into the reinforcing layer of the pharmaceutical packaging composite film to synthesize nano-masterbatch, and uses nano-aluminum nano-masterbatch as the raw material of the reinforcing layer, thereby greatly improving the peel strength of the composite film.

[0015] The adhesive layer of the pharmaceutical packaging composite film of the present invention uses a modified tackifying resin and adds freeze-dried graphene oxide powder. The appropriate amount of freeze-dried graphene oxide powder content significantly improves the peel strength of the composite film.

[0016] The synergistic effect of nano-aluminum masterbatch and freeze-dried graphene oxide powder modified tackifying resin results in a pharmaceutical packaging composite film with high peel strength prepared by this patent. Attached Figure Description

[0017] Figure 1 This is a simplified diagram of the four-layer co-extruded film structure of the present invention.

[0018] Figure 2 This is a field emission scanning image of the four-layer co-extruded film material of the present invention.

[0019] Figure 3 The bar chart shows the mechanical strength of Embodiment 1 and Comparative Examples 1-6 of the present invention.

[0020] Figure 4 The bar chart shows the barrier performance of Embodiment 1 and Comparative Examples 1-6 of the present invention.

[0021] Figure 5 The graphs show the heat-sealing intensity at different temperatures for Embodiment 1 and Comparative Examples 1-6 of the present invention.

[0022] Figure 6 Line graphs showing the heat-sealing strength under different pressures in Embodiment 1 and Comparative Examples 1-6 of the present invention.

[0023] Figure 7 The bar chart shows the mechanical strength of Embodiment 2 and Comparative Examples 7-9 of the present invention.

[0024] Figure 8 These are Raman spectra of graphene and graphene oxide. Detailed Implementation

[0025] As a special commodity used to treat and prevent various diseases, pharmaceuticals often receive widespread attention from the public. Many factors influence drug quality, and pharmaceutical packaging materials are one of the most crucial. According to the "General Requirements and Guidelines for Pharmaceutical Packaging Materials," pharmaceutical packaging materials refer to the packaging materials and containers that come into direct contact with pharmaceuticals produced by pharmaceutical manufacturers and preparations compounded by medical institutions. Therefore, pharmaceutical packaging materials are an indispensable part of pharmaceuticals. Using safe pharmaceutical packaging materials can protect pharmaceuticals during transportation and storage, isolating them from the external environment as much as possible and preventing deterioration or ineffectiveness. Therefore, only by selecting qualified pharmaceutical packaging materials and appropriate packaging methods can the quality of pharmaceuticals be safely and effectively ensured, allowing the public to purchase and use medications with confidence. Example 1

[0026] S1. Preparation of the corona layer: Weigh 55% high-density polyethylene, 30% linear low-density polyethylene, 10% polytetrafluoroethylene, and 5% methyl silicone oil according to the mass ratio. Then, place the high-density polyethylene and linear low-density polyethylene in a mixer, start the machine, add methyl silicone oil to wet the surfaces of the high-density polyethylene and linear low-density polyethylene, and then add polytetrafluoroethylene to make the polytetrafluoroethylene completely adhere to the surfaces of the high-density polyethylene and linear low-density polyethylene. Subsequently, the above mixture is granulated into nanoparticles using a twin-screw granulator.

[0027] S2. Preparation of the reinforcing layer: First, 35% nano-Al, 25% nano-TiO2, 15% nano-SiO2, and 25% nano-attapulgite were weighed according to the following mass ratio. After high-speed mixing for ten minutes, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanocomposite particles. Then, 20% nanocomposite particles, 46% low-density polyethylene, 22% linear low-density polyethylene, 9% ethylene bis-stearamide, 1% polytetrafluoroethylene, and 2% methoxysilane coupling agent were weighed according to the following mass ratio. After high-speed mixing for half an hour, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanomasterbatch. Finally, 85% nanomasterbatch, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio. These were mixed using a mixer and then granulated using a twin-screw extruder to form nanoparticles.

[0028] S3. Preparation of heat-sealing layer: Weigh 50% metallocene polyethylene, 10% fluorinated ethylene propylene copolymer, 5% methyl silicone oil and 35% aluminum strip according to the mass ratio, mix them with a mixer and then form nanoparticles using a twin-screw granulator.

[0029] S4. Preparation of the adhesive layer: First, the tackifying resin was modified. 4 g of dehydrated hydroxyl-terminated butadiene-acrylonitrile rubber was dissolved in 20 mL of N,N-dimethylformamide, followed by the addition of 0.5 g of lyophilized graphene oxide powder and ultrasonic treatment for 1 h to obtain an N,N-dimethylformamide solution of graphene-based toughening agent. Then, 20 g of epoxy resin was added, and after reaction, the modified tackifying resin was obtained. Next, 60% polyethylene-methyl methacrylate, 25% tackifying resin, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio, mixed in a mixer, and then granulated into nanoparticles using a twin-screw extruder.

[0030] S5. Preparation of the four-layer co-extruded film: The nanoparticles in S1-S4 are sequentially processed into a composite film with a thickness of 0.1 mm using a four-layer co-extruded casting film production unit, consisting of a corona layer, a reinforcing layer, a heat-sealing layer, and an adhesive layer. Then, a 3-5 μm thick ethylene-acrylic acid copolymer coating is applied to the outer layer of the four-layer co-extruded film using an extruder. The outer layer of the co-extruded film needs to be corona treated to improve the adhesion and peel strength between the outer layer and the ethylene-acrylic acid copolymer coating.

[0031] Comparative Example 1 is identical to Example 1 except for step S2, which is omitted.

[0032] Comparative Example 2 is identical to Example 1 except for step S3, which is omitted.

[0033] Comparative Example 3 was identical to Example 1 except that in step S4, polyethylene-methyl methacrylate was replaced with polypropylene-methyl methacrylate.

[0034] Comparative Example 4: Except for replacing the fluorinated ethylene propylene copolymer in step S2 with polytetrafluoroethylene, all other steps were the same as in Example 1.

[0035] Comparative Example 5: Except for replacing the fluorinated ethylene propylene copolymer in step S3 with polytetrafluoroethylene, all other steps were the same as in Example 1.

[0036] Comparative Example 6: Except for replacing the fluorinated ethylene propylene copolymer in step S4 with polytetrafluoroethylene, all other steps were the same as in Example 1.

[0037] Detection method:

[0038] 1. Peel strength: According to the peel strength test method.

[0039] 2. Heat seal strength: According to the heat seal strength test method.

[0040] 3. Oxygen permeability: According to the method for measuring gas permeability.

[0041] 4. Water vapor transmission rate: Infrared detector method.

[0042] Table 1

[0043] Testing items Peel strength (N / 15mm) Heat seal strength (N / 15mm) Example 1 12±0.01 38±0.01 Comparative Example 1 3.4±0.02 18±0.01 Comparative Example 2 4.2±0.01 12±0.01 Comparative Example 3 8.2±0.02 24±0.01 Comparative Example 4 7.6±0.01 26±0.01 Comparative Example 5 8.9±0.02 28±0.01 Comparative Example 6 6.7±0.01 20±0.01

[0044] Table 2

[0045] Testing items <![CDATA[Oxygen Permeability (cm 3 / m 2 24h 0.1MPa)]]> <![CDATA[Water vapor transmission rate (g / m 2 24h)]]> Example 1 0.1±0.01 0.05±0.01 Comparative Example 1 0.5±0.01 0.48±0.01 Comparative Example 2 0.42±0.01 0.48±0.01 Comparative Example 3 0.33±0.01 0.42±0.01 Comparative Example 4 0.21±0.01 0.32±0.01 Comparative Example 5 0.25±0.01 0.29±0.01 Comparative Example 6 0.18±0.01 0.21±0.01

[0046] Table 1 is a statistical table of mechanical strength data for Embodiment 1 and Comparative Examples 1-6 of the present invention, and Table 2 is a statistical table of barrier performance data for Embodiment 1 and Comparative Examples 1-6 of the present invention. Figure 3 The bar charts show the mechanical strength of Embodiment 1 and Comparative Examples 1-6 of the present invention. Figure 7 The bar chart shows the barrier performance of Embodiment 1 and Comparative Examples 1-6 of the present invention. Figure 4 The graphs show the heat-sealing strength at different temperatures for Embodiment 1 and Comparative Examples 1-6 of the present invention. Figure 5 This is a line graph showing the heat-sealing strength under different pressures for Embodiment 1 and Comparative Examples 1-6 of the present invention. (From Table 1 and...) Figure 3 It can be seen that the composite film in Example 1 has stronger heat-sealing strength and peel strength, indicating that the four-layer co-extruded film has better peel strength and heat-sealing strength than the three-layer co-extruded film. From Table 2 and... Figure 4 It can be seen that the four-layer co-extruded film in Example 1 has better barrier properties, indicating that the four-layer co-extruded film has a significantly stronger protective effect on pharmaceuticals than the three-layer co-extruded film. The corona layer composed of high-pressure polyethylene and linear low-density polyethylene can better prevent the oxidation and deterioration of pharmaceuticals, thus extending their shelf life. Because the reinforcing layer in the four-layer co-extruded film of Example 1 is synthesized through three steps, the final synthesized nano-masterbatch provides a better peel strength improvement to the pharmaceutical composite film than nanocomposite particles or ordinary polyethylene nanoparticles. Example 2

[0047] S1. Preparation of the corona layer: Weigh out 55% medium-density polyethylene, 30% linear low-density polyethylene, 10% polytetrafluoroethylene, and 5% methyl silicone oil according to the mass ratio. Then, place the high-density polyethylene and linear low-density polyethylene in a mixer, start the machine, add methyl silicone oil to wet the surfaces of the high-density polyethylene and linear low-density polyethylene, and then add polytetrafluoroethylene to make the polytetrafluoroethylene completely adhere to the surfaces of the high-density polyethylene and linear low-density polyethylene. Subsequently, use a twin-screw granulator to form nanoparticles from the above mixture.

[0048] S2. Preparation of the reinforcing layer: First, 35% nano-Al, 25% nano-TiO2, 15% nano-SiO2, and 25% nano-attapulgite were weighed according to the following mass ratio. After high-speed mixing for ten minutes, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanocomposite particles. Then, 20% nanocomposite particles, 46% low-density polyethylene, 22% linear low-density polyethylene, 9% ethylene bis-stearamide, 1% polytetrafluoroethylene, and 2% methoxysilane coupling agent were weighed according to the following mass ratio. After high-speed mixing for half an hour, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanomasterbatch. Finally, 85% nanomasterbatch, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio. These were mixed using a mixer and then granulated using a twin-screw extruder to form nanoparticles.

[0049] S3. Preparation of heat-sealing layer: Weigh 50% metallocene polyethylene, 10% fluorinated ethylene propylene copolymer, 5% methyl silicone oil and 35% aluminum strip according to the mass ratio, mix them with a mixer and then form nanoparticles using a twin-screw granulator.

[0050] S4. Preparation of the adhesive layer: First, the tackifying resin was modified. 4 g of dehydrated hydroxyl-terminated butadiene-acrylonitrile rubber was dissolved in 20 mL of N,N-dimethylformamide, followed by the addition of 0.5 g of lyophilized graphene oxide powder and ultrasonic treatment for 1 h to obtain an N,N-dimethylformamide solution of graphene-based toughening agent. Then, 20 g of epoxy resin was added, and after reaction, the modified tackifying resin was obtained. Next, 60% polyethylene-methyl methacrylate, 25% tackifying resin, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio, mixed in a mixer, and then granulated into nanoparticles using a twin-screw extruder.

[0051] S5. Preparation of the four-layer co-extruded film: The nanoparticles in S1-S4 are sequentially processed into a composite film with a thickness of 0.1 mm using a four-layer co-extruded casting film production unit, consisting of a corona layer, a reinforcing layer, a heat-sealing layer, and an adhesive layer. Then, a 3-5 μm thick ethylene-acrylic acid copolymer coating is applied to the outer layer of the four-layer co-extruded film using an extruder. The outer layer of the co-extruded film needs to be corona treated to improve the adhesion and peel strength between the outer layer and the ethylene-acrylic acid copolymer coating.

[0052] Comparative Example 7 was identical to Example 2 except that step S2 was changed to weighing 85% polyethylene, 10% fluorinated ethylene propylene copolymer and 5% methyl silicone oil by mass ratio, mixing them in a mixer and then forming nanoparticles using a twin-screw granulator.

[0053] Comparative Example 8: Except for step S2, which was changed to first weighing 35% nano-Al, 25% nano-TiO2, 15% nano-SiO2, and 25% nano-attapulgite clay according to the mass ratio, mixing them at high speed for ten minutes, then extruding them using a screw extruder, cooling and cutting to obtain nanocomposite particles. Alternatively, 85% nanocomposite particles, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the mass ratio, mixed in a mixer, and then granulated using a twin-screw extruder to form nanoparticles. All other steps were the same as in Example 2.

[0054] Comparative Example 9 is identical to Example 2 except that nano-Al is replaced with nano-Cu in step S2.

[0055] Table 3

[0056] Testing items Peel strength (N / 15mm) Heat seal strength (N / 15mm) Example 2 12±0.01 38±0.01 Comparative Example 7 6.5±0.01 18±0.01 Comparative Example 8 9.2±0.01 28±0.01 Comparative Example 9 7.8±0.01 21±0.01

[0057] Table 3 is a statistical table of mechanical strength data for Embodiment 2 and Comparative Examples 7-9 of the present invention. Figure 7 This is a bar chart showing the mechanical strength of Embodiment 2 and Comparative Examples 7-9 of the present invention. (From Table 3 and...) Figure 7 It can be seen that the four-layer co-extruded film in Example 2 has a higher peel strength. If the peel strength of the pharmaceutical packaging composite film material is low, delamination is likely to occur after the medicine is placed inside the packaging. This reduces the physical and mechanical properties of the packaging material, such as barrier properties and impact resistance, and also affects the efficacy of the packaged medicine, significantly impacting its drug efficacy. The four-layer co-extruded film in Example 2, due to the addition of a reinforcing layer synthesized through three steps, produces a final nano-masterbatch that provides a better peel strength improvement for the pharmaceutical composite film compared to nanocomposite particles and ordinary polyethylene nanoparticles. Example 3

[0058] S1. Preparation of the corona layer: Weigh out 55% medium-density polyethylene, 30% linear low-density polyethylene, 10% polytetrafluoroethylene, and 5% methyl silicone oil according to the mass ratio. Then, place the high-density polyethylene and linear low-density polyethylene in a mixer, start the machine, add methyl silicone oil to wet the surfaces of the high-density polyethylene and linear low-density polyethylene, and then add polytetrafluoroethylene to make the polytetrafluoroethylene completely adhere to the surfaces of the high-density polyethylene and linear low-density polyethylene. Subsequently, use a twin-screw granulator to form nanoparticles from the above mixture.

[0059] S2. Preparation of the reinforcing layer: First, 35% nano-Al, 25% nano-TiO2, 15% nano-SiO2, and 25% nano-attapulgite were weighed according to the following mass ratio. After high-speed mixing for ten minutes, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanocomposite particles. Then, 20% nanocomposite particles, 46% low-density polyethylene, 22% linear low-density polyethylene, 9% ethylene bis-stearamide, 1% polytetrafluoroethylene, and 2% methoxysilane coupling agent were weighed according to the following mass ratio. After high-speed mixing for half an hour, the mixture was extruded using a screw extruder, cooled, and cut to obtain nanomasterbatch. Finally, 85% nanomasterbatch, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio. These were mixed using a mixer and then granulated using a twin-screw extruder to form nanoparticles.

[0060] S3. Preparation of heat-sealing layer: Weigh 50% metallocene polyethylene, 10% fluorinated ethylene propylene copolymer, 5% methyl silicone oil and 35% aluminum strip according to the mass ratio, mix them with a mixer and then form nanoparticles using a twin-screw granulator.

[0061] S4. Preparation of the adhesive layer: First, the tackifying resin was modified. 4 g of dehydrated hydroxyl-terminated butadiene-acrylonitrile rubber was dissolved in 20 mL of N,N-dimethylformamide, followed by the addition of 0.5 g of lyophilized graphene oxide powder and ultrasonic treatment for 1 h to obtain an N,N-dimethylformamide solution of graphene-based toughening agent. Then, 20 g of epoxy resin was added, and after reaction, the modified tackifying resin was obtained. Next, 60% polyethylene-methyl methacrylate, 25% tackifying resin, 10% fluorinated ethylene propylene copolymer, and 5% methyl silicone oil were weighed according to the following mass ratio, mixed in a mixer, and then granulated into nanoparticles using a twin-screw extruder.

[0062] S5. Preparation of the four-layer co-extruded film: The nanoparticles in S1-S4 are sequentially processed into a composite film with a thickness of 0.1 mm using a four-layer co-extruded casting film production unit, consisting of a corona layer, a reinforcing layer, a heat-sealing layer, and an adhesive layer. Then, a 3-5 μm thick ethylene-acrylic acid copolymer coating is applied to the outer layer of the four-layer co-extruded film using an extruder. The outer layer of the co-extruded film needs to be corona treated to improve the adhesion and peel strength between the outer layer and the ethylene-acrylic acid copolymer coating.

[0063] Comparative Example 10: In step S4, 0.5g of freeze-dried graphene oxide powder was replaced with 0g, and all other steps were the same as in Example 3.

[0064] Comparative Example 11: The 0.5g freeze-dried graphene oxide powder in step S4 was changed to 0.1g, and all other steps were the same as in Example 3.

[0065] Comparative Example 12: The 0.5g freeze-dried graphene oxide powder in step S4 was changed to 0.3g, and all other steps were the same as in Example 3.

[0066] Comparative Example 13: The 0.5g freeze-dried graphene oxide powder in step S4 was changed to 0.8g, and all other steps were the same as in Example 3.

[0067] Comparative Example 14: In step S4, 0.5g of freeze-dried graphene oxide powder was replaced with 1g, and all other steps were the same as in Example 3.

[0068] Table 4

[0069] Testing items Peel strength (N / 15mm) Heat seal strength (N / 15mm) Example 3 12±0.01 38±0.01 Comparative Example 10 2±0.01 9±0.01 Comparative Example 11 7.8±0.01 28±0.01 Comparative Example 12 8.8±0.01 21±0.01 Comparative Example 13 9.2±0.01 35±0.01 Comparative Example 14 6.5±0.01 18±0.01

[0070] Table 4 shows the mechanical strength data of Example 3 and Comparative Examples 10-14 of this invention. As can be seen from Table 3, the four-layer co-extruded film in Example 3 has a higher peel strength. The four-layer co-extruded film in Example 3, due to the addition of a reinforcing layer synthesized through three steps and the alteration of the freeze-dried graphene oxide powder content, clearly shows that the composite film containing freeze-dried graphene oxide powder has significantly greater mechanical strength than the composite film without it. The synergistic effect of the nano-aluminum masterbatch and the freeze-dried graphene oxide powder-modified tackifying resin results in the high peel strength of the pharmaceutical packaging composite film prepared by this patent.

[0071] Finally, it should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a pharmaceutical packaging composite film having an ultrastrong peeling strength, characterized by The steps are as follows: S1, preparation of the corona layer: according to the mass ratio, 55% high-pressure polyethylene, 30% linear low-density polyethylene, 10% polytetrafluoroethylene and 5% methyl silicone oil are weighed, then the high-pressure polyethylene and linear low-density polyethylene are placed in a mixer, the machine is started, the methyl silicone oil is added to wet the surface of the high-pressure polyethylene and linear low-density polyethylene, then the polytetrafluoroethylene is added, so that the polytetrafluoroethylene is fully attached to the surface of the high-pressure polyethylene and linear low-density polyethylene, and then the above mixture is granulated into nano particles by a double screw granulator; S2, preparation of the reinforcing layer: first, 35% nano Al, 25% nano TiO2, 15% nano SiO2 and 25% nano attapulgite are weighed according to the mass ratio, mixed at high speed for ten minutes, then extruded by a screw, cooled and cut to prepare nano composite particles; then, 20% nano composite particles, 46% low-density polyethylene, 22% linear low-density polyethylene, 9% ethylene bis-stearamide, 1% polytetrafluoroethylene and 2% methoxysilane coupling agent are weighed according to the mass ratio, mixed at high speed for half an hour, then extruded by a screw, cooled and cut to prepare nano masterbatch; the nano masterbatch, fluorinated ethylene propylene copolymer and methyl silicone oil are weighed according to the mass ratio, mixed by a mixer, then granulated into nano particles by a double screw granulator; S3, preparation of the heat-sealing layer: metallocene polyethylene, fluorinated ethylene propylene copolymer, methyl silicone oil and aluminum strip are weighed according to the mass ratio, mixed by a mixer, then granulated into nano particles by a double screw granulator; S4, preparation of the adhesive layer: first, the tackifying resin is modified, 4 g of hydroxyl-terminated nitrile rubber after dehydration treatment is dissolved in 20 mL of N,N-dimethylformamide, then 0.5 g of freeze-dried graphene oxide powder is added and ultrasonically treated for 1 h to obtain a N,N-dimethylformamide solution of graphene-based toughening agent, then 20 g of epoxy resin is added, and after reaction, a modified tackifying resin is obtained; then, polyethylene-methyl methacrylate, tackifying resin, fluorinated ethylene propylene copolymer and methyl silicone oil are weighed according to the mass ratio, mixed by a mixer, then granulated into nano particles by a double screw granulator; S5, preparation of the four-layer co-extruded film: the nano particles in S1-S4 are sequentially used to prepare a composite film with a thickness of 0.1 mm by a four-layer co-extrusion flow casting film production unit; then, an extruder is used to coat a 3-5 μm thick ethylene-acrylic acid copolymer coating on the outer layer of the four-layer co-extruded film.

2. The method of claim 1, wherein the method is characterized by: The polytetrafluoroethylene in S1 is a low molecular weight polytetrafluoroethylene.

3. The method of claim 1, wherein the method is characterized by: The nano Al in S2 is a mixture of nano Al and nano Al2O3.

4. The method of claim 1 or 3, wherein the method is characterized by: The nano attapulgite in S2 is nylon-modified nano attapulgite.

5. The method of claim 1, wherein the method is characterized by: The epoxy resin in S4 is a bisphenol A type epoxy resin.

6. The pharmaceutical packaging composite film prepared by the preparation method according to any one of claims 1-5.

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