A low-temperature heat-sealed composite film for pharmaceutical packaging

Abstract

The present invention relates to a low-temperature heat-sealable composite film for pharmaceutical packaging, belonging to the technical field of pharmaceutical packaging. The present invention provides a low-temperature heat-sealable composite film for pharmaceutical packaging. The composite film is formed by laminating a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer, followed by drying in a gradient temperature increase manner. The aluminum foil outer layer of the prepared composite film provides oxygen and moisture resistance, the polyester film middle layer provides mechanical support, and the mussel mucin inner layer directly contacts the pharmaceutical. The prepared composite film for pharmaceutical packaging can achieve heat sealing at relatively low temperatures, effectively preserving the pharmaceutical.

Description

Technical Field

[0001] The invention belongs to the technical field of medicinal packaging and relates to a low-temperature heat-sealed medicinal packaging composite film. Background Art

[0002] Pharmaceutical packaging films, typically composed of aluminum foil and polymer plastic film, are widely used to package and protect pharmaceuticals, aiming to protect them from adverse environmental influences, improve their stability, and extend their shelf life. Polyester film, currently one of the most commonly used packaging films, operates at relatively high heat-sealing temperatures. For packaging specific items, such as pharmaceuticals, improvements are needed to prevent degradation of heat-sensitive components caused by traditional heat-sealing temperatures above 130°C. Summary of the Invention

[0003] The object of the present invention is to provide a low-temperature heat-sealed composite film for pharmaceutical packaging. The present invention prepares a pharmaceutical packaging film with a multi-layer composite structure. The outer layer of aluminum foil blocks oxygen and moisture, the middle layer of polyester film provides mechanical support, and the inner layer of mussel mucin directly contacts the medicine. The prepared pharmaceutical packaging composite film can be heat-sealed at a relatively low temperature and effectively preserve the medicine.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A low-temperature heat-sealed composite film for pharmaceutical packaging, comprising a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer stacked in sequence;

[0006] The stacking is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner.

[0007] Furthermore, the thickness of the mussel mucin inner layer is 6-8 μm; the thickness of the polyester film middle layer is 10-14 μm; and the thickness of the aluminum foil outer layer is 7-9 μm.

[0008] Furthermore, the adhesive used to achieve the lamination is water-based polyurethane, and the bonding pressure is 0.3-0.5 MPa; the gradient temperature drying method refers to first curing at 55-65°C for 11-13 hours, and then heating to 70-80°C and maintaining for 5-7 hours.

[0009] Furthermore, the method for preparing the mussel mucin inner layer comprises the following steps:

[0010] Step A1, the modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 10-30 nm, vitamin E, and deionized water are mixed in a mass ratio of 1-1.5:0.5-0.8:0.2-0.3:0.1-0.2:0.04-0.06:8.1-8.5, the ultrasonic frequency is set to 30-50 kHz, the ultrasonic power is 100-200 W, and the ultrasonic treatment is carried out for 15-25 minutes. The mixture is then coated on the surface of a polyester film with a coating thickness of 1.2-1.8 μm, and then dried at 60° C. to obtain a mussel mucin inner layer.

[0011] Furthermore, the method for preparing the modified mussel mucin powder in step A1 comprises the following steps:

[0012] Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, and simultaneously adding hydrochloric acid dropwise to adjust the pH to 4.8-5.2, and then bathing in a water bath at 58-62° C. for 3-4 hours to obtain a primary product;

[0013] Step B2: adding 0.5-1 wt% of genipin to the initial product, standing at room temperature for 10-14 hours, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder.

[0014] Furthermore, in step B1, the mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer is 1:0.03-0.07:0.004-0.006:10-12; the concentration of the PBS buffer is 0.01-0.02 mol / L; and the concentration of the hydrochloric acid is 0.1-0.2 mol / L.

[0015] Furthermore, the polyester film in step A1 is subjected to plasma treatment, specifically by introducing argon and oxygen in a ratio of 4:1, setting the power to 200-300 W, and plasma treatment for 86-94 seconds.

[0016] Beneficial effects of the present invention:

[0017] (1) The present invention provides a pharmaceutical packaging film with a multi-layer composite structure, wherein the outer layer of aluminum foil blocks oxygen and moisture, the middle layer of polyester film provides mechanical support, and the inner layer of mussel mucin directly contacts the medicine. The prepared pharmaceutical packaging composite film can be heat-sealed at a relatively low temperature, effectively preserving the medicine.

[0018] (2) The hydrophobic surface of the inner layer of the mussel mucin in the present invention can reduce the moisture absorption of the drug. The mussel mucin itself has good viscosity, and the mussel mucin carries dopa residues. The dopa residues have phenolic hydroxyl groups that may form molecular hydrogen bonds with the carboxyl groups on the polyacrylic acid formed by the polymerization of acrylic acid monomers to form a complex, thereby introducing flexible chain ends on the protein molecular chain and combining with acetyl tributyl citrate plasticizer to reduce the temperature requirement during heat sealing, promote interface diffusion flow, and achieve adhesion effect; on this basis, genipin is used to react with mussel mucin to form a heat-resistant cross-linked network, inhibit the movement of the protein molecular chain, and reduce the risk of creep during use; in addition, a gradient heating drying process is adopted in the preparation process to ensure the curing of the adhesive while avoiding long-term high-temperature exposure of the mussel mucin during the early preparation. DETAILED DESCRIPTION

[0019] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0020] The mussel mucins in all the embodiments and comparative examples of the present invention were purchased directly from the market and purchased from Hubei Langbowan Biotechnology Co., Ltd.; acrylic acid, potassium persulfate, PBS buffer, hydrochloric acid, and Jingni average were purchased directly from the market and purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.; water-based polyurethanes were purchased directly from the market and purchased from Anhui Femtosecond Chemical Co., Ltd.; acetyl tributyl citrate was purchased directly from the market and purchased from Weifang Hanghao New Material Technology Co., Ltd.; nano-silica was purchased directly from the market and purchased from Hubei Xinyuhong Biotechnology Co., Ltd.; vitamin E was purchased directly from the market and purchased from Jiangsu Huace Biotechnology Co., Ltd.; aluminum foil was purchased directly from the market and purchased from Gongyi Boyu Aluminum Sales Co., Ltd.

[0021] Example 1

[0022] A low-temperature heat-sealed composite film for pharmaceutical packaging, the composite film for pharmaceutical packaging of this embodiment comprises a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer stacked in sequence;

[0023] The stacking is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner.

[0024] In this embodiment, the thickness of the inner layer of mussel mucin is 6 μm; the thickness of the middle layer of polyester film is 10 μm; and the thickness of the outer layer of aluminum foil is 7 μm.

[0025] The adhesive used to achieve the lamination in this embodiment is water-based polyurethane, and the bonding pressure is 0.3 MPa; the gradient temperature drying method means first curing at 55° C. for 11 hours, and then heating to 70° C. and maintaining for 5 hours.

[0026] The preparation method of the mussel mucin inner layer of this embodiment comprises the following steps:

[0027] Step A1: Modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 10 nm, vitamin E, and deionized water are mixed in a mass ratio of 1:0.5:0.2:0.1:0.04:8.1, the ultrasonic frequency is set to 30 kHz, the ultrasonic power is 100 W, and after ultrasonication for 15 minutes, the mixture is coated on the surface of a polyester film with a coating thickness of 1.2 μm, and then dried at 60°C to obtain a mussel mucin inner layer.

[0028] The method for preparing the modified mussel mucin powder in step A1 of this embodiment comprises the following steps:

[0029] Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, while adding hydrochloric acid dropwise to adjust the pH to 4.8, and bathing in a water bath at 58° C. for 34 hours to obtain a primary product;

[0030] Step B2: adding 0.5 wt% of genipin to the initial product, standing at room temperature for 10 h, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder.

[0031] In step B1 of this embodiment, the mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer is 1:0.03:0.004:10; the concentration of PBS buffer is 0.01 mol / L; and the concentration of hydrochloric acid is 0.1 mol / L.

[0032] In step A1 of this embodiment, the polyester film is subjected to plasma treatment. Specifically, argon and oxygen are introduced in a ratio of 4:1, the power is set to 200 W, and the plasma treatment is performed for 86 seconds.

[0033] Example 2

[0034] A low-temperature heat-sealed composite film for pharmaceutical packaging, the composite film for pharmaceutical packaging of this embodiment comprises a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer stacked in sequence;

[0035] The stacking is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner.

[0036] In this embodiment, the thickness of the inner layer of mussel mucin is 6.7 μm; the thickness of the middle layer of polyester film is 11 μm; and the thickness of the outer layer of aluminum foil is 7.5 μm.

[0037] The adhesive used to achieve the lamination in this embodiment is water-based polyurethane, and the bonding pressure is 0.35 MPa; the gradient temperature drying method means first curing at 57° C. for 11.6 hours, and then heating to 73° C. and maintaining for 5.5 hours.

[0038] The preparation method of the mussel mucin inner layer of this embodiment comprises the following steps:

[0039] Step A1: Modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 15 nm, vitamin E, and deionized water are mixed in a mass ratio of 1.2:0.6:0.23:0.12:0.04:8.2, the ultrasonic frequency is set to 35 kHz, the ultrasonic power is 120 W, and after ultrasonication for 18 minutes, the coating is applied to the surface of the polyester film with a coating thickness of 1.4 μm, and then dried at 60°C to obtain the mussel mucin inner layer.

[0040] The method for preparing the modified mussel mucin powder in step A1 of this embodiment comprises the following steps:

[0041] Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, while adding hydrochloric acid dropwise to adjust the pH to 4.9, and then bathing in a 59° C. water bath for 3.2 hours to obtain a primary product;

[0042] Step B2: adding 0.6 wt% of genipin to the initial product, standing at room temperature for 11 h, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder.

[0043] In step B1 of this embodiment, the mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer is 1:0.04:0.004:10.8; the concentration of PBS buffer is 0.01 mol / L; and the concentration of hydrochloric acid is 0.1 mol / L.

[0044] In step A1 of this embodiment, the polyester film is subjected to plasma treatment. Specifically, argon and oxygen are introduced in a ratio of 4:1, the power is set to 220 W, and the plasma treatment is performed for 88 seconds.

[0045] Example 3

[0046] A low-temperature heat-sealed composite film for pharmaceutical packaging, the composite film for pharmaceutical packaging of this embodiment comprises a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer stacked in sequence;

[0047] The stacking is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner.

[0048] In this embodiment, the thickness of the inner layer of mussel mucin is 7 μm; the thickness of the middle layer of polyester film is 12 μm; and the thickness of the outer layer of aluminum foil is 8 μm.

[0049] The adhesive used to achieve the lamination in this embodiment is water-based polyurethane, and the bonding pressure is 0.4 MPa; the gradient temperature drying method means first curing at 60° C. for 12 hours, and then heating to 75° C. and maintaining for 6 hours.

[0050] The preparation method of the mussel mucin inner layer of this embodiment comprises the following steps:

[0051] Step A1: Modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 20 nm, vitamin E, and deionized water are mixed in a mass ratio of 1.25:0.65:0.25:0.15:0.05:8.3, the ultrasonic frequency is set to 40 kHz, the ultrasonic power is 150 W, and after ultrasonication for 20 minutes, the coating is applied to the surface of the polyester film with a coating thickness of 1.5 μm, and then dried at 60°C to obtain the mussel mucin inner layer.

[0052] The method for preparing the modified mussel mucin powder in step A1 of this embodiment comprises the following steps:

[0053] Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, while adding hydrochloric acid dropwise to adjust the pH to 5, and then bathing in a 60° C. water bath for 3.5 hours to obtain a primary product;

[0054] Step B2: adding 0.75 wt% of genipin to the initial product, standing at room temperature for 12 h, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder.

[0055] In step B1 of this embodiment, the mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer is 1:0.05:0.005:11; the concentration of PBS buffer is 0.015 mol / L; and the concentration of hydrochloric acid is 0.15 mol / L.

[0056] In step A1 of this embodiment, the polyester film is subjected to plasma treatment. Specifically, argon and oxygen are introduced in a ratio of 4:1, the power is set to 250 W, and the plasma treatment is performed for 90 seconds.

[0057] Example 4

[0058] A low-temperature heat-sealed composite film for pharmaceutical packaging, the composite film for pharmaceutical packaging of this embodiment comprises a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer stacked in sequence;

[0059] The stacking is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner.

[0060] In this embodiment, the thickness of the inner layer of mussel mucin is 7.5 μm; the thickness of the middle layer of polyester film is 13 μm; and the thickness of the outer layer of aluminum foil is 8.2 μm.

[0061] The adhesive used to achieve the lamination in this embodiment is water-based polyurethane, and the bonding pressure is 0.45 MPa; the gradient temperature drying method means first curing at 62° C. for 12.6 hours, and then heating to 77° C. and maintaining for 6.5 hours.

[0062] The preparation method of the mussel mucin inner layer of this embodiment comprises the following steps:

[0063] Step A1: Modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 25 nm, vitamin E, and deionized water are mixed in a mass ratio of 1.4:0.72:0.28:0.17:0.06:8.4, the ultrasonic frequency is set to 45 kHz, the ultrasonic power is 180 W, and after ultrasonication for 22 minutes, the coating is applied to the surface of the polyester film with a coating thickness of 1.6 μm, and then dried at 60°C to obtain the mussel mucin inner layer.

[0064] The method for preparing the modified mussel mucin powder in step A1 of this embodiment comprises the following steps:

[0065] Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, while adding hydrochloric acid dropwise to adjust the pH to 5.1, and then bathing in a 61° C. water bath for 3.6 hours to obtain a primary product;

[0066] Step B2: adding 0.87 wt% of genipin to the initial product, standing at room temperature for 13 h, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder.

[0067] In step B1 of this embodiment, the mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer is 1:0.06:0.006:11.7; the concentration of PBS buffer is 0.02 mol / L; and the concentration of hydrochloric acid is 0.2 mol / L.

[0068] In step A1 of this embodiment, the polyester film is subjected to plasma treatment. Specifically, argon and oxygen are introduced in a ratio of 4:1, the power is set to 280 W, and the plasma treatment is performed for 92 seconds.

[0069] Example 5

[0070] A low-temperature heat-sealed composite film for pharmaceutical packaging, the composite film for pharmaceutical packaging of this embodiment comprises a mussel mucin inner layer, a polyester film middle layer, and an aluminum foil outer layer stacked in sequence;

[0071] The stacking is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner.

[0072] In this embodiment, the thickness of the inner layer of mussel mucin is 8 μm; the thickness of the middle layer of polyester film is 14 μm; and the thickness of the outer layer of aluminum foil is 9 μm.

[0073] The adhesive used to achieve the lamination in this embodiment is water-based polyurethane, and the bonding pressure is 0.5 MPa; the gradient temperature drying method means first curing at 65° C. for 13 hours, and then heating to 80° C. and maintaining for 7 hours.

[0074] The preparation method of the mussel mucin inner layer of this embodiment comprises the following steps:

[0075] Step A1: Modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 30 nm, vitamin E, and deionized water are mixed in a mass ratio of 1.5:0.8:0.3:0.2:0.06:8.5, the ultrasonic frequency is set to 50 kHz, the ultrasonic power is 200 W, and after ultrasonication for 25 minutes, the mixture is coated on the surface of a polyester film with a coating thickness of 1.8 μm, and then dried at 60°C to obtain a mussel mucin inner layer.

[0076] The method for preparing the modified mussel mucin powder in step A1 of this embodiment comprises the following steps:

[0077] Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, while adding hydrochloric acid dropwise to adjust the pH to 5.2, and then bathing in a 62° C. water bath for 4 h to obtain a primary product;

[0078] Step B2: adding 1 wt% of genipin to the initial product, standing at room temperature for 14 hours, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder.

[0079] In step B1 of this embodiment, the mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer is 1:0.07:0.006:12; the concentration of PBS buffer is 0.02 mol / L; and the concentration of hydrochloric acid is 0.2 mol / L.

[0080] In step A1 of this embodiment, the polyester film is subjected to plasma treatment. Specifically, argon and oxygen are introduced in a ratio of 4:1, the power is set to 300 W, and the plasma treatment is performed for 94 seconds.

[0081] Example 6

[0082] On the basis of Example 3, the mussel mucin powder was not modified, and other conditions remained the same as in Example 3.

[0083] Example 7

[0084] On the basis of Example 3, acetyl tributyl citrate used in the preparation of the mussel mucin inner layer was removed and replaced with an equal weight of deionized water. Other conditions remained the same as in Example 3.

[0085] Example 8

[0086] On the basis of Example 3, the nano-silica used in the preparation of the inner layer of mussel mucin was removed and replaced with an equal weight of deionized water. Other conditions remained the same as in Example 3.

[0087] Comparative Example 1

[0088] On the basis of Example 3, keeping other conditions the same, the preparation method of the modified mussel mucin powder was changed to the following steps:

[0089] Step B1: add mussel mucin to PBS buffer, then add acrylic acid and potassium persulfate, and simultaneously add hydrochloric acid dropwise to adjust the pH to 5. Incubate in a 60° C. water bath for 3.5 h, dialyze to remove unreacted monomers, and freeze-dry to obtain modified mussel mucin powder.

[0090] Comparative Example 2

[0091] On the basis of Example 3, the drying step in the gradient temperature rising mode was changed to curing at 75° C. for 18 h, and other conditions remained the same as in Example 3.

[0092] Comparative Example 3

[0093] On the basis of Example 3, the polyester film in step A1 is not subjected to plasma treatment, and other conditions remain the same as those in Example 3.

[0094] Comparative Example 4

[0095] On the basis of Example 3, keeping other conditions the same, the operation of plasma treatment of the polyester film in step A1 was changed to introducing argon gas, setting the power to 250 W, and plasma treatment for 90 seconds.

[0096] Comparative Example 5

[0097] On the basis of Example 3, keeping other conditions the same, the operation of plasma treatment of the polyester film in step A1 was changed to introducing argon and oxygen in a ratio of 1:1, setting the power to 250 W, and plasma treatment for 90 s.

[0098] The pharmaceutical packaging composite films prepared in Examples 1-8 and Comparative Examples 1-5 were used as samples. The heat seal strength of the samples was tested at 180 kPa and 100° C. for 1 second. Five parallel sets of samples were prepared for each group. The average of the results was recorded in Table 1 below.

[0099] Table 1

[0100]

[0101]

[0102] As shown in Table 1, the pharmaceutical packaging composite film prepared by the present invention can still obtain good heat sealing strength at a relatively low heat sealing temperature, and can reduce the effect of high temperature on drug stability in practical applications.

[0103] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any indirect modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A low-temperature heat-sealed composite film for pharmaceutical packaging, characterized in that: The medicinal packaging composite film comprises a mussel mucin inner layer, a polyester film middle layer and an aluminum foil outer layer stacked in sequence; The lamination is achieved by drying the inner layer of mussel mucin, the middle layer of polyester film and the outer layer of aluminum foil in a gradient temperature rising manner; The preparation method of the mussel mucin inner layer comprises the following steps: Step A1, after mixing the modified mussel mucin powder, water-based polyurethane, acetyl tributyl citrate, nano-silica with an average particle size of 10-30 nm, vitamin E, and deionized water in a mass ratio of 1-1.5:0.5-0.8:0.2-0.3:0.1-0.2:0.04-0.06:8.1-8.5, setting the ultrasonic frequency to 30-50 kHz and the ultrasonic power to 100-200 W, ultrasonicating for 15-25 minutes, coating the mixture on the surface of a polyester film to a coating thickness of 1.2-1.8 μm, and then drying at 60° C. to obtain a mussel mucin inner layer; The method for preparing the modified mussel mucin powder described in step A1 comprises the following steps: Step B1, adding mussel mucin to PBS buffer, then adding acrylic acid and potassium persulfate, and simultaneously adding hydrochloric acid dropwise to adjust the pH to 4.8-5.2, and then bathing in a water bath at 58-62° C. for 3-4 hours to obtain a primary product; Step B2, adding 0.5-1 wt% of genipin to the primary product, standing at room temperature for 10-14 hours, dialyzing to remove unreacted monomers, and freeze-drying to obtain modified mussel mucin powder; The mass ratio of mussel mucin, acrylic acid, potassium persulfate, and PBS buffer in step B1 is 1:0.03-0.07:0.004-0.006:10-12; the concentration of the PBS buffer is 0.01-0.02 mol / L; and the concentration of the hydrochloric acid is 0.1-0.2 mol / L. In step A1, the polyester film is subjected to plasma treatment. Specifically, argon and oxygen are introduced in a ratio of 4:1, the power is set to 200-300W, and the plasma treatment is performed for 86-94s.

2. The low-temperature heat-sealable composite film for pharmaceutical packaging according to claim 1, characterized in that: The thickness of the mussel mucin inner layer is 6-8 μm; the thickness of the polyester film middle layer is 10-14 μm; and the thickness of the aluminum foil outer layer is 7-9 μm.

3. The low-temperature heat-sealable composite film for pharmaceutical packaging according to claim 1, characterized in that: The adhesive used to achieve the lamination is water-based polyurethane, and the bonding pressure is 0.3-0.5 MPa; the gradient temperature drying method means first curing at 55-65°C for 11-13 hours, and then heating to 70-80°C and maintaining for 5-7 hours.

Images