Moisture-proof and bacteriostatic traditional Chinese medicine composite packaging bag

Abstract

This invention relates to the field of packaging bag technology, specifically to a moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine. It comprises an outer protective film layer, a middle buffer transition layer, a moisture-proof barrier layer, an antibacterial functional layer, and an inner contact film layer. These layers are arranged from the outside in. The outer protective film layer, middle buffer transition layer, moisture-proof barrier layer, antibacterial functional layer, and inner contact film layer are composited using food-grade adhesives. The middle buffer transition layer is made of low-density polyethylene elastic film. The moisture-proof barrier layer is composited with polyvinyl alcohol high-barrier film and passivated aluminum foil film. The antibacterial functional layer uses food-grade polyolefin film as the substrate. The inner contact film layer uses food-grade polyethylene film. This invention has the following advantages: it integrates multiple benefits such as wear resistance, long-lasting moisture and oxygen barrier, active antibacterial properties, and safety and non-toxicity. Its service life and protective effect are far superior to traditional single-layer and ordinary double-layer packaging.

Description

Technical Field

[0001] This invention relates to the field of packaging bag technology, specifically to moisture-proof and antibacterial composite packaging bags for traditional Chinese medicine. Background Technology

[0002] Most mainstream Chinese medicine packaging bags on the market today use simple structures such as single-layer films or ordinary double-layer composite films. Their overall protective performance is insufficient, making them unsuitable for the long-term storage and long-distance transportation of Chinese medicinal materials, processed slices, and powders, exhibiting significant limitations. These traditional packaging bags lack a dedicated multi-layer barrier structure, relying solely on ordinary plastic film for basic sealing, offering limited protection against moisture and oxygen. When stored in humid warehouses or transported long distances through rainy areas, external moisture can easily penetrate the film and enter the bag. Chinese medicinal herbs are rich in starch, sugars, and volatile oils, which are hygroscopic, leading to clumping, softening, and mold growth after absorbing moisture. Simultaneously, the infiltrated oxygen accelerates the oxidation of active ingredients, resulting in loss of efficacy and quality deterioration. Furthermore, the film is not hydrophobically modified, causing its barrier performance to rapidly decline in high-humidity environments, making long-term protection difficult. In addition, conventional packaging only passively blocks external microorganisms through sealing; the film material itself does not possess antibacterial capabilities. Chinese medicine is rich in nutrients. If trace amounts of moisture and air remain in the bag, it is very easy for harmful bacteria such as Escherichia coli, Staphylococcus aureus, and Aspergillus niger to grow, causing the medicinal materials to become moldy and infested with insects, greatly shortening the shelf life, and even producing toxic and harmful substances, thus creating hidden dangers for medication safety. Summary of the Invention

[0003] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine, comprising an outer protective film layer, an intermediate buffer transition layer, a moisture-proof barrier layer, an antibacterial functional layer, and an inner contact film layer. The outer protective film layer, intermediate buffer transition layer, moisture-proof barrier layer, antibacterial functional layer, and inner contact film layer are arranged from the outside to the inside. These layers are composited using a food-grade adhesive. The intermediate buffer transition layer is made of low-density polyethylene elastic film. The moisture-proof barrier layer is composited with a polyvinyl alcohol high-barrier film and a passivated aluminum foil film. The antibacterial functional layer uses a food-grade polyolefin film as the substrate. The inner contact film layer uses a food-grade polyethylene film. The five-layer integrated composite structure has a clear division of labor. Combined with food-grade adhesives, the overall structure is stable. The middle buffer transition layer enhances impact resistance. The combination of polyvinyl alcohol high-barrier film and passivated aluminum foil film strengthens moisture and oxygen barrier performance. The independent antibacterial functional layer achieves active antibacterial properties. The inner contact film layer ensures contact safety. The structure solves the problem of single protection in traditional packaging and improves the overall performance.

[0005] Specifically, the outer protective film is made of biaxially oriented polypropylene (BOP) film. The original roll of BOP film undergoes surface dust removal and static electricity removal treatment. Subsequently, a high-intensity corona treatment device is used to activate the inner surface of the BOP film with corona power controlled at 800–1200W and a processing speed of 15–25m / min. This creates a micro-uneven structure on the inner surface of the BOP film, improving the adhesion strength to the adhesive and intermediate buffer layer. Simultaneously, a matte abrasion-resistant coating and a weather-resistant protective coating are roller-coated onto the outer surface of the BOP film. The coating thickness of the matte abrasion-resistant coating and the weather-resistant protective coating is controlled at 5–10μm. After coating, the film is placed in a constant temperature oven and dried and cured at 60–70℃ for 20–30 minutes to prevent coating peeling and sagging. After dust removal, static electricity removal, and corona activation treatment, a micro-rough surface is formed, which enhances the interlayer adhesion. The outer surface is coated with a wear-resistant and weather-resistant coating and cured at high temperature, which can resist friction, sun exposure and damage from complex external environments, prevent coating peeling and bag damage, and extend the service life of the packaging.

[0006] Specifically, the intermediate buffer transition layer is made of low-density polyethylene (LDPE) elastic film, and the inner contact film layer is made of food-grade polyethylene film. Both the LDPE elastic film and the food-grade polyethylene film undergo high-temperature impurity removal and stretching straightening treatments to remove residual volatile additives and internal stresses from their production processes, ensuring their flexibility and flatness. The high-temperature impurity removal and stretching straightening treatments of the intermediate buffer transition layer and the inner contact film layer remove residual additives and internal stresses, resulting in a flexible and flat film. This not only improves the user experience and bending resistance but also prevents impurities in the film material from contaminating the traditional Chinese medicine, further enhancing the cleanliness and stability of the packaging.

[0007] Specifically, the moisture-proof barrier layer is formed by composite molding of a polyvinyl alcohol high-barrier film and a passivated aluminum foil film. First, a 6-12 μm thick aluminum foil film undergoes double-sided passivation and anti-corrosion treatment. Then, it is composited with the polyvinyl alcohol high-barrier film using a hot-pressing process at 110-125℃ and 0.3-0.5 MPa. Simultaneously, 20-50 nm hydrophobic nano-silica powder is uniformly incorporated into the polyvinyl alcohol high-barrier film to enhance its hydrophobic and water-blocking capabilities. After double-sided passivation and anti-corrosion treatment, combined with the hot-pressing composite of the polyvinyl alcohol high-barrier film and the incorporation of hydrophobic nano-powder, the double-barrier structure and hydrophobic modification result in extremely low water vapor and oxygen penetration. The barrier performance decays slowly under high humidity conditions, achieving long-lasting moisture and oxygen protection and safeguarding the quality of traditional Chinese medicine.

[0008] Specifically, the antibacterial functional layer uses food-grade polyolefin film as the substrate. During the melt extrusion stage, 1.2%–2.5% by weight of organosilicon-coated modified nano-silver ion antibacterial powder and 1.8%–3.2% by weight of a compound plant-derived antibacterial extract of artemisia, clove, and forsythia are added. The mixture is thoroughly mixed using a twin-screw extruder to ensure that the antibacterial components are non-agglomerated and uniformly dispersed. After extrusion molding, the inner and outer surfaces of the food-grade polyolefin film are treated with a micro-textured embossing process. Using a food-grade polyolefin substrate, compounded with inorganic antibacterial powder and natural plant antibacterial extracts, and uniformly mixed without agglomeration, this method combines chemical and plant-based antibacterial effects. The micro-textured embossing design on the film surface also reduces moisture adhesion, further enhancing the antibacterial and moisture-proof effects, and leaves no chemical residue, making it safe and environmentally friendly.

[0009] Specifically, the food-grade composite adhesive is prepared as follows: water-based polyurethane adhesive is selected as the base, and moisture-proof additives are added according to the usage environment. After stirring evenly, the solid content of the adhesive is controlled at 35% to 45%, and the viscosity is maintained at 1800 to 2500 mPa·s to ensure uniform coating and no harmful substances are released. After completing the above preparations, the step-by-step lamination process is started. Dry lamination equipment is used to laminate layer by layer in the order from the outside to the inside. The coating thickness of the outer protective film layer, the intermediate buffer transition layer, the moisture-proof barrier layer, the antibacterial functional layer, and the inner contact film layer is controlled at 8 to 15 μm. The lamination temperature is set at 75 to 90℃, and the lamination linear speed is 10 to 20 m / min. After each two layers of film are laminated, they are sent to the curing chamber and cured at 40 to 50℃ for 24 to 36 hours to eliminate the internal stress of the composite and prevent the film layers from delaminating and peeling. Specialized water-based polyurethane adhesives, combined with moisture-proof additives, are non-toxic, harmless, and suitable for humid environments. The step-by-step lamination and layered curing process can release internal stress in the film layer, avoiding defects such as delamination, warping, debonding, and air leakage, ensuring strong integrity and reliable sealing performance after multilayer film lamination.

[0010] Specifically, using high-speed slitting and bag-making equipment, rectangular bags are formed by cutting to set dimensions and heat-sealing the sides. Finally, a full range of finished product inspections are conducted, including tests for film adhesion, water vapor transmission rate, oxygen transmission rate, antibacterial performance, and food and drug safety migration. Defective products, such as those with delamination, leaks, insufficient antibacterial properties, or the presence of harmful substance migration, are rejected. Qualified products are then sorted, packaged, and stored. Through specialized equipment, water vapor and oxygen transmission rate tests and long-term high humidity simulation experiments are performed. The packaging exhibits excellent barrier performance with minimal performance degradation, providing long-term protection against water vapor and oxygen intrusion, meeting the moisture-proof and oxygen-barrier requirements for long-term storage and long-distance transportation of traditional Chinese medicine.

[0011] Specifically, the finished moisture-proof and antibacterial composite packaging bags for traditional Chinese medicine, after being cut and sorted, are inspected manually using calipers and rulers. Visual inspection confirms the bag surface is free of scratches, bubbles, pinholes, color differences, and coating peeling. The multi-layered films show no delamination, peeling, or detachment. The side heat-sealed edges are continuous, uniform, and without any gaps. Measuring tools are used to measure the overall dimensions of the bag, the thickness of each film layer, and the width of the heat-sealed edges. All dimensions meet design tolerance requirements. The finished products undergo a full visual and dimensional inspection using measuring tools to rigorously eliminate defects such as scratches, pinholes, bubbles, gaps, and delamination. This ensures that each packaging bag has a neat appearance, standard dimensions, and a tight seal, controlling the quality of the finished product from both appearance and structure.

[0012] Specifically, professional water vapor transmission rate testers and oxygen transmission rate testers are used to test the overall water vapor transmission rate and oxygen transmission rate of the packaging bag according to national standard methods. The water vapor transmission rate is required to be ≤3g / (m²・24h) and the oxygen transmission rate is required to be ≤0.5cm³ / (m²・24h・atm). At the same time, a high humidity environment simulation test is conducted, in which the packaging bag is placed in a constant temperature and humidity chamber with a relative humidity of 85% and a temperature of 25℃ for 90 consecutive days. The barrier performance is tested regularly, and the performance degradation rate is required to be less than 5%.

[0013] Specifically, for antibacterial performance testing, referring to the "Test Method for Antibacterial Performance of Antimicrobial Plastics," three typical bacteria species for traditional Chinese medicine storage—Escherichia coli, Staphylococcus aureus, and Aspergillus niger—were selected for quantitative antibacterial testing. The bacterial solution was inoculated onto the inner surface of the packaging bag, incubated at a constant temperature for 24 hours, and then counted. The antibacterial rate for all three bacteria was required to be no less than 90%. Simultaneously, a long-term antibacterial test was conducted, with the antibacterial rate retested after the sample was placed at room temperature for 6 months to ensure the long-term sustained release and stable performance of the antibacterial components. By conducting quantitative and long-term antibacterial tests according to national standards, the packaging bag demonstrated excellent antibacterial rates against the target harmful bacteria, and the antibacterial components were long-lasting, stable, and not easily degraded. No additional chemical insecticides or antibacterial agents were needed, thus avoiding the risk of chemical residues at the source and ensuring the safety of traditional Chinese medicine use.

[0014] The beneficial effects of this invention are:

[0015] Composed of an outer protective film, a middle buffer transition layer, a moisture-proof barrier layer, an antibacterial functional layer, and an inner contact film layer, this multi-layered structure functions synergistically. The outer protective film undergoes corona activation and wear-resistant and weather-resistant coating treatment, resulting in a firm and wear-resistant surface that resists friction, scratches, and external environmental erosion during transportation. It also enhances interlayer adhesion strength, preventing film detachment and delamination. The middle buffer transition layer uses an elastic film material that, after impurity removal and stress relief treatment, exhibits excellent flexibility and flatness, buffering external impacts and further ensuring the integrity of the overall structure. This packaging bag integrates multiple advantages such as wear-resistant protection, long-lasting moisture and oxygen barrier, active antibacterial properties, and safety and non-toxicity. Its service life and protective effect are far superior to traditional single-layer and ordinary double-layer packaging, extending the shelf life of traditional Chinese medicine and reducing losses during storage and transportation. It is suitable for the entire process of packaging various traditional Chinese medicine products.

[0016] The moisture-proof barrier layer is made of polyvinyl alcohol high-barrier film and passivated aluminum foil film, combined with hydrophobic nanoparticle modification to enhance the barrier ability against water vapor and oxygen, preventing external water vapor and air from penetrating into the bag. Even in long-term high-humidity storage and rainy transportation environments, the barrier performance of the film has a small decline, which can effectively prevent Chinese medicine from clumping, softening and mold due to moisture absorption. At the same time, it slows down the oxidation and decomposition of active ingredients, stabilizes the medicinal properties and quality of medicinal materials, and solves the defect of short moisture-proof effect of traditional packaging.

[0017] The antibacterial functional layer endows the packaging with active antibacterial capabilities. The film material is compounded with nano silver ion antibacterial powder and natural plant antibacterial extracts such as artemisia, clove, and forsythia. Various antibacterial components are evenly dispersed and released slowly over a long period of time. They can directly inhibit the growth of harmful microorganisms such as Escherichia coli, Staphylococcus aureus, and Aspergillus niger, preventing the medicinal materials from becoming moldy and infested with insects. This method eliminates the need for chemical fumigation and the addition of insect repellents, and will not produce harmful substance residues. It complies with pharmaceutical packaging safety regulations and ensures medication safety.

[0018] The inner contact membrane is made of food-grade material, which does not release harmful substances when in direct contact with Chinese medicine, making it safe and reliable. Each membrane layer is processed and formed by special food-grade adhesive, combined with segmented composite and constant temperature curing process, to eliminate composite internal stress and prevent problems such as membrane layer lifting, delamination, and air leakage. The finished product has undergone strict testing in multiple dimensions, and its barrier performance and antibacterial effect meet the standard requirements. Attached Figure Description

[0019] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0020] Figure 1 This is a schematic diagram of the structure of the moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine of the present invention.

[0021] In the picture:

[0022] 100. Outer protective film layer; 200. Intermediate buffer transition layer; 300. Moisture-proof barrier layer; 400. Antibacterial functional layer; 500. Inner contact film layer. Detailed Implementation

[0023] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0024] Please see Figure 1 This invention provides a technical solution: a moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine, comprising, from the outside to the inside, an outer protective film layer 100, an intermediate buffer transition layer 200, a moisture-proof barrier layer 300, an antibacterial functional layer 400, and an inner contact film layer 500. Each film layer is composited with a food-grade adhesive. The preparation method includes, in sequence, substrate pretreatment, separate preparation of each functional film layer, adhesive preparation, multilayer film step-by-step lamination, slitting and bag making, and finished product testing.

[0025] First, pretreatment of the substrates for each film layer is carried out. For the outer protective film layer 100, which is made of biaxially oriented polypropylene film, the original roll of biaxially oriented polypropylene film is first subjected to surface dust removal and static electricity removal treatment. Then, a corona treatment device is used to perform high-intensity corona activation on the inner surface of the biaxially oriented polypropylene film. The corona power is controlled at 800-1200W and the processing speed is 15-25m / min. This creates a micro-uneven structure on the inner surface of the biaxially oriented polypropylene film, which improves the adhesion strength with the adhesive and transition layer. At the same time, a matte wear-resistant coating and a weather-resistant protective coating are roller-coated on the outer surface of the biaxially oriented polypropylene film. The coating thickness is controlled at 5-10μm. After coating, the film is placed in a constant temperature oven and dried and cured at 60-70℃ for 20-30min to prevent the coating from peeling off or dripping.

[0026] The low-density polyethylene elastic film used in the intermediate buffer transition layer 200 and the food-grade polyethylene film used in the inner contact film layer 500 are subjected to high-temperature impurity removal and stretching straightening treatments in sequence to remove residual volatile additives and internal stresses from the production process of the low-density polyethylene elastic film and the food-grade polyethylene film, ensuring the flexibility and flatness of the film.

[0027] The moisture barrier layer 300 is made of polyvinyl alcohol high barrier film and passivated aluminum foil film. First, the aluminum foil film with a thickness of 6-12μm is subjected to double-sided passivation and anti-corrosion treatment. Then, it is composited with polyvinyl alcohol high barrier film using a hot pressing process at 110-125℃ and 0.3-0.5MPa. At the same time, 20-50nm hydrophobic nano silica powder is uniformly incorporated into the polyvinyl alcohol high barrier film to improve the hydrophobic and water-blocking ability.

[0028] The antibacterial functional layer 400 uses food-grade polyolefin film as the base material. During the melt extrusion stage, 1.2% to 2.5% by mass of organosilicon-coated modified nano silver ion antibacterial powder and 1.8% to 3.2% by mass of artemisia, clove and forsythia compound plant-derived antibacterial extracts are added. The mixture is fully mixed by a twin-screw extruder to ensure that the antibacterial components are not agglomerated and are evenly dispersed. After extrusion molding, the inner and outer surfaces of the film are subjected to micro-textured embossing treatment.

[0029] Food-grade composite adhesive formulation: Water-based polyurethane adhesive is selected as the base, and moisture-proof additives are added according to the environment in which the composite film is used. After stirring evenly, the solid content of the adhesive is controlled at 35% to 45%, and the viscosity is maintained at 1800 to 2500 mPa·s to ensure uniform coating and no harmful substances are released.

[0030] After completing the above preparations, start the step-by-step lamination process. Use dry lamination equipment to laminate layer by layer from the outside to the inside. The thickness of each membrane coating is controlled at 8-15 μm. The lamination temperature is set at 75-90℃ and the lamination linear speed is 10-20 m / min. After each two membranes are laminated, send them to the curing chamber and cure them at 40-50℃ for 24-36 hours to eliminate internal stress and prevent membrane delamination and warping.

[0031] The completed roll of composite film enters the sealing structure integral molding process. Two sets of interlocking sealing strips are integrally formed at the corresponding position of the bag opening using a co-extrusion process. Rectangular sealing stickers and bent dustproof edge protectors are simultaneously pasted to ensure that the sealing components are firmly bonded to the bag body. Subsequently, the bag is cut to the set size and the side sealing edges are heat-sealed through a high-speed slitting and bag-making equipment to complete the rectangular bag body forming.

[0032] The specific steps for the preparation and surface coating processing of the outer protective film layer 100 are as follows: The outer protective film layer 100 is made of biaxially oriented polypropylene film with a thickness of 30-50 μm. First, the original roll of biaxially oriented polypropylene film is installed on the unwinding frame. The unwinding device is started to feed the film at a uniform speed. The film feeding speed is stably controlled at 18 m / min. The film surface static electricity is removed by an electrostatic eliminator to avoid adsorption of dust and fine impurities during the production process. Then, the upper and lower surfaces of the film are thoroughly cleaned by a brush dust removal group to ensure that the cleanliness of the film surface meets the composite requirements.

[0033] After dust removal and static electricity removal, the biaxially oriented polypropylene film is sent to the corona treatment unit. The distance between the corona electrode and the surface of the biaxially oriented polypropylene film is adjusted to 1.5-2.5 mm, and the corona power is set to 900 W. The entire area of ​​the biaxially oriented polypropylene film facing inward is subjected to corona activation treatment. After corona treatment, the surface tension of the film is checked by sampling with surface tension test liquid. The surface tension is required to be no less than 38 mN / m. If the test does not meet the standard, the corona power is finely adjusted and the treatment is repeated to ensure that the film surface has excellent adhesion conditions.

[0034] After corona treatment, a double-coating roller coating operation is performed on the outer surface of the biaxially oriented polypropylene film. The first coating is a matte abrasion-resistant coating, applied using a 120-mesh anilox roller. The dry film thickness is controlled at 6–8 μm. After coating, the film enters the first drying channel, where the drying temperature is set at 62℃, the hot air velocity is 3 m / s, and the drying time is 22 minutes to allow the matte coating to initially cure. Subsequently, a second weather-resistant protective coating is applied, again using a 120-mesh anilox roller, with a dry film thickness of 5–7 μm. After coating, the film enters the second drying channel, where the drying temperature is increased to 68℃ and the drying time is 25 minutes. After both coatings are fully cured, the biaxially oriented polypropylene film is naturally cooled to room temperature to eliminate localized high-temperature stress generated during coating curing.

[0035] After the coating process is completed, the outer protective film layer 100 is subjected to appearance and performance spot checks. The appearance requirements are that the film surface is free of coating runs, pinholes, scratches, and color differences, and there is no peeling between the coating and the base film. The performance test focuses on abrasion resistance and aging resistance. A reciprocating friction test is conducted using an abrasion testing machine. After 500 reciprocating friction cycles, there are no obvious scratches on the film surface and the coating does not fall off. At the same time, a simulated light aging test is conducted. After 1000 hours of continuous irradiation by ultraviolet lamps, there are no obvious changes in the mechanical strength and color of the film layer. Only after the weather resistance meets the standards can it proceed to the next composite process.

[0036] Through refined surface treatment and a double-coating step-by-step curing process, the outer protective film's resistance to friction, aging, and light erosion is enhanced, protecting the inner functional film layer from the outer packaging level. At the same time, the standardized sampling inspection process can screen out unqualified substrates in advance, avoiding material waste in subsequent processes. The entire process is suitable for batch continuous production, and the process parameters can be slightly adjusted according to the thickness of the biaxially oriented polypropylene film and the temperature and humidity of the production environment, always ensuring the stable and reliable comprehensive performance of the outer protective film.

[0037] The pretreatment and molding auxiliary processes of the intermediate buffer transition layer 200 and the inner contact film layer 500 are as follows: The intermediate buffer transition layer 200 is made of food-grade low-density polyethylene elastic film with a thickness of 20-35μm, and the inner contact film layer 500 is made of additive-free food-grade polyethylene film with a thickness of 15-25μm. Both types of films are packaging substrates that directly or indirectly contact the Chinese medicine materials. Therefore, the entire pretreatment process is completed in a Class 100,000 clean production workshop. The workshop environment is strictly controlled. The indoor temperature is maintained at 22-26℃, the relative humidity is controlled at 45%-55%, and the concentration of suspended particulate matter in the air meets the cleanliness standards for pharmaceutical packaging production, thus preventing dust and bacteria from contaminating the film.

[0038] First, the two types of film rolls, low-density polyethylene elastic film and polyethylene film, are unwound and straightened. The unwinding tension is adjusted evenly to avoid film stretching deformation, wrinkles and deviation. The unwinding speed is uniformly set to 16m / min. The film passes through multiple sets of guide rollers and flattening rollers in sequence. The arc structure of the flattening rollers is used to completely flatten the film, eliminate the film's own curling stress, and ensure that the film surface is flat and smooth.

[0039] Then, a high-temperature deodorization and volatile matter removal treatment is carried out. The flattened film is sent into a low-temperature hot air treatment channel. The temperature inside the channel is set to 55-60℃, and the hot air is circulated. The treatment time is 18-24 minutes. This gradually removes the trace amounts of low-molecular-weight additives and volatile gases remaining in the film production process, preventing volatile substances from migrating into the Chinese medicine material during subsequent use and affecting the quality and safety of Chinese medicine.

[0040] After the deodorization treatment is completed, the upper and lower surfaces of the intermediate buffer transition layer 200 and the outer surface of the inner contact film layer 500 are lightly sanded and roughened. The ultra-fine nylon brush set is used for flexible sanding, and the sanding depth is controlled at 1 to 2 μm. Only a micro-rough structure is formed on the film surface without damaging the overall mechanical strength of the film. The purpose of the roughening treatment is to improve the interlocking ability between the film and the adhesive, further strengthen the bonding strength after the multilayer film is composited, and avoid the composite delamination problem caused by the film surface being too smooth.

[0041] After polishing, the film undergoes a second brush dust removal and static elimination process to clean up any fine plastic debris generated during polishing. Before formal lamination, the mechanical properties of both types of films are sampled and tested, with a focus on tensile strength, elongation at break, and puncture resistance. The intermediate buffer transition layer 200 requires an elongation at break of no less than 300%, possessing excellent cushioning and shock absorption capabilities to absorb the extrusion impact during transport and stacking, preventing sharp medicinal materials from puncturing the film. The inner contact film layer 500 requires a smooth surface, free of burrs and exudates, and the migration of harmful substances must fully comply with the relevant standards of the "Regulations on the Management of Materials and Containers for Pharmaceutical Packaging". After all test items are qualified, the two types of films are rolled up for later use. During rolling, the rolling tension is controlled to be uniform, and the film roll ends are neat, without misalignment or local extrusion deformation. The pretreatment process focuses on clean production, stress relief, safe impurity removal, and interface optimization. It is designed for the hygiene requirements and operating conditions of traditional Chinese medicine packaging, ensuring both the structural stability and cushioning protection of the film itself, while completely eliminating the safety hazards inherent in the substrate, laying the foundation for subsequent multi-layer lamination and long-term use of the finished packaging.

[0042] The specific steps of the preparation process of the moisture barrier layer 300 are as follows: The moisture barrier layer 300 is composed of polyvinyl alcohol high barrier film and aluminum foil film. The overall thickness is controlled at 25-40μm. It is the core functional layer for realizing moisture protection, oxygen barrier and light protection of packaging bags. The preparation process is divided into four major steps: aluminum foil film passivation treatment, polyvinyl alcohol film modification and mixing, hot pressing of the two films, and performance testing.

[0043] The first step is to carry out passivation and anti-corrosion treatment of aluminum foil film. Industrial pure aluminum foil film with a thickness of 6-12μm is selected as the substrate. First, the aluminum foil film is unrolled and flattened to remove rolling oil and oxidation impurities from the surface. Then, it is sent into the passivation treatment tank and double-sided immersion passivation is carried out using chromium-based environmentally friendly passivation solution. The immersion time is controlled at 8-12 seconds, and the passivation solution temperature is maintained at 28-32℃. This allows a dense and stable anti-corrosion passivation film to be uniformly formed on both the upper and lower surfaces of the aluminum foil film. After passivation, the surface of the aluminum foil film is rinsed multiple times with deionized water to remove residual passivation solution. Then, it is sent into the hot air drying channel and dried at 70-75℃ for 15-20 minutes. After drying, there are no watermarks or residual solutions on the surface of the aluminum foil film, and the passivation film is complete and continuous. This can prevent the aluminum foil from oxidizing, corroding, and blackening in a high-humidity storage environment and avoid corrosion impurities from contaminating the chemical materials.

[0044] The second step involves the preparation of a modified polyvinyl alcohol (PVA) high-barrier membrane. Food-grade PVA resin is used as the matrix material, and hydrophobic nano-silica powder with a particle size of 20–50 nm is added in a specific ratio. The powder addition percentage is 2.0%–3.5% of the PVA resin mass. The raw materials are fed into a high-speed mixer and stirred at room temperature for 25–35 minutes to ensure that the hydrophobic powder is uniformly dispersed in the resin matrix without agglomeration. After mixing, the mixture is melt-extruded and cast using a single-screw extruder. The extrusion temperature is controlled in stages: 160℃ in zone 1, 175℃ in zone 2, 185℃ in zone 3, and 190℃ at the die. After casting and cooling, the modified PVA high-barrier membrane is obtained. The internal pores of this membrane are filled with nanoparticles, significantly improving its hydrophobic and gas barrier properties.

[0045] The third step involves hot-pressing the two films together. A double-roller hot-pressing lamination device is used to precisely align the passivated aluminum foil film and the modified polyvinyl alcohol film. The polyvinyl alcohol film faces the middle buffer transition layer 200, and the aluminum foil film faces the antibacterial functional layer 400. The temperature of the hot-pressing roller is set to 110-125℃, the lamination pressure is 0.3-0.5MPa, and the lamination linear speed is 12m / min. The film condition is observed in real time during the hot-pressing process to ensure that the two films are fully bonded and that there are no bubbles, wrinkles, or local voids inside. After the hot-pressing lamination is completed, the film is allowed to cool naturally to room temperature.

[0046] The fourth step involves conducting performance testing on the moisture-proof barrier layer. This includes sampling and testing water vapor transmission rate, oxygen transmission rate, and bending resistance. The overall water vapor transmission rate must be below 3 g / (m²・24h), and the oxygen transmission rate must be less than 0.5 cm³ / (m²・24h・atm). After 1000 consecutive bends, the film must show no pinholes, no breaks, and no significant decrease in barrier performance. Simultaneously, the composite strength of the aluminum foil and polyvinyl alcohol film is tested, with a peel strength of not less than 1.2 N / 15 mm. Only after all indicators meet the standards can the film be rolled up and transferred to the subsequent multi-layer composite process. Through a combination of aluminum foil passivation, hydrophobic modification of the matrix, and high-temperature hot-pressing composite, a dual moisture-proof and oxygen-barrier system is constructed, improving the stability of the barrier layer under high humidity and long-term storage conditions, thus meeting the storage requirements of traditional Chinese medicine materials for moisture absorption, oxidation prevention, and mildew prevention.

[0047] The specific process of mixing, extrusion, and micro-texturing of the antibacterial functional layer 400 is as follows: The antibacterial functional layer 400 uses food-grade polyolefin as the film substrate, and is compounded with nano silver ion antibacterial powder and plant-derived antibacterial extract. It has the characteristics of long-lasting antibacterial effect, safety and non-toxicity, and good composite with adjacent film layers. The whole process is divided into several steps, including raw material ratio, high-temperature mixing, melt extrusion, micro-texturing embossing, cooling and winding, and pre-testing of antibacterial performance.

[0048] First, precise raw material proportions are determined. 88.3–97 parts by weight of food-grade polyolefin resin are used as the main substrate, and 1.2–2.5 parts of silicone-coated modified nano-silver ion antibacterial powder and 1.8–3.2 parts of compounded plant-derived antibacterial extract are added. The plant-derived antibacterial extract is prepared by mixing Artemisia argyi extract, clove extract, and Forsythia suspensa extract in a mass ratio of 3:2:2. All raw materials are put into a closed mixing silo, which is kept clean and dry to prevent external bacteria and dust from entering the raw material system.

[0049] Next, a twin-screw high-temperature mixing process is carried out. The proportioned raw materials are transported to a twin-screw extruder. The temperature of each section of the equipment is controlled in zones: Zone 1 155℃, Zone 2 165℃, Zone 3 172℃, and Zone 4 168℃. The screw speed is set to 220 r / min, and the mixing time is 12-18 min. The organosilicon coating layer can effectively protect the nano silver ion particles and prevent them from agglomerating and becoming ineffective under high-temperature mixing conditions. At the same time, it allows the nano antibacterial components and plant antibacterial components to be evenly integrated into the resin matrix, avoiding the local accumulation of antibacterial components.

[0050] The mixed molten material enters the die head for casting and extrusion. The width of the die head is set according to the width of the packaging bag. The extrusion temperature is stabilized at 170℃. After extrusion, the molten film enters the cooling roller group. The surface temperature of the cooling roller is controlled at 25-30℃, and the initial antibacterial film is quickly formed.

[0051] Immediately after the film is shaped, it enters the micro-textured embossing process. A pair of embossing rollers with fine embossing textures are used to emboss both the top and bottom surfaces of the film. The embossing pressure is 0.2-0.4 MPa and the embossing texture depth is 3-5 μm. This micro-texture can increase the contact area between the film and the adhesive, improve the composite bonding strength, and slow down the release rate of antibacterial components to achieve long-lasting slow-release antibacterial effect. At the same time, it can prevent a large amount of antibacterial components from falling off and coming into contact with the medicinal materials.

[0052] After embossing, the film is cooled, flattened, and dust-removed before being wound up. The winding tension is uniform, and the film roll is consistently tight. After winding, samples are taken for pre-testing of antibacterial performance. According to national standard testing methods, the samples are exposed to common harmful microorganisms in traditional Chinese medicine storage, such as Escherichia coli, Staphylococcus aureus, and Aspergillus niger. After 24 hours of constant temperature incubation, the antibacterial rate is tested. The antibacterial rate for each type of bacteria is required to be no less than 90%. At the same time, the amount of harmful substances released from the film is tested to ensure that the antibacterial components do not migrate to the traditional Chinese medicine materials and comply with the safety regulations for pharmaceutical packaging. For batches with substandard antibacterial rates or uneven component distribution, the mixing speed, temperature, and raw material ratio are readjusted, and secondary processing is carried out until qualified. The quality of the antibacterial functional layer 400 is controlled throughout the entire process, from raw material modification, high-temperature protection, structural optimization, and performance pre-testing, to achieve synergistic and long-lasting antibacterial effect of nano-silver and plant extracts, taking into account antibacterial effect, safety of use, and composite processing performance.

[0053] The specific processes of food-grade composite adhesive preparation, coating, film lamination, and segmented curing are as follows: Water-based polyurethane food-grade adhesive is used as the multilayer film lamination medium to eliminate organic solvent residues and meet the safety requirements of traditional Chinese medicine packaging. The adhesive treatment and film lamination are divided into four core stages: adhesive preparation, online coating, dry lamination, and segmented curing.

[0054] First, the adhesive is precisely formulated. Food-grade water-based polyurethane adhesive concentrate is selected as the base. Based on the high humidity conditions of the packaging bags, moisture-proof additives are added at 4% to 6% of the concentrate mass. At the same time, deionized water is added to adjust the overall viscosity of the adhesive. The formulation process is carried out using a low-speed stirrer at a speed of 60 to 80 r / min at room temperature for 18 to 25 minutes to ensure that the additives and adhesive are completely integrated without stratification or sedimentation. After formulation, the adhesive indicators are tested to control the solid content to 35% to 45%, the viscosity to 1800 to 2500 mPa·s, and the pH value to 6.5 to 7.5. Only after all indicators meet the standards can the adhesive be sent to the coating equipment hopper.

[0055] Secondly, online coating operations are carried out using a dry laminating machine in conjunction with an anilox roller for adhesive application. The anilox roller with the corresponding mesh size is selected according to the surface characteristics of different film layers. For the outer protective film layer 100 and the moisture barrier layer 300, a 100-mesh anilox roller is used, and the dry amount of adhesive is controlled at 10-15 g / ㎡. For the intermediate buffer transition layer 200, the antibacterial functional layer 400, and the inner contact film layer 500, a 120-mesh anilox roller is used, and the dry amount of adhesive is controlled at 8-12 g / ㎡. During the adhesive application process, the rotation speed of the anilox roller and the level of adhesive are monitored in real time to ensure that the adhesive layer on the film surface is continuous and uniform, without any missed coating, adhesive accumulation, or adhesive breakage.

[0056] The coated film immediately enters the drying unit. The drying temperature is set in three gradients: 65℃ in the first stage, 75℃ in the second stage, and 82℃ in the third stage. This gradually evaporates the moisture in the adhesive, preventing the adhesive layer from drying too quickly and generating bubbles. After drying, the adhesive layer is in a semi-cured state and has good adhesive activity.

[0057] Subsequently, a multilayer film dry lamination process is performed, strictly following the sequence of "outer protective film layer 100 → intermediate buffer transition layer 200 → moisture barrier layer 300 → antibacterial functional layer 400 → inner contact film layer 500". The lamination roller temperature is set at 75-90℃, the lamination pressure at 0.4-0.6MPa, and the production line speed is controlled at 10-20m / min. After every two layers of film are laminated, the laminated film undergoes a visual inspection, and semi-finished products with bubbles, wrinkles, or misalignments are rejected. Finally, the final product is processed... The film rolls are subjected to segmented constant temperature curing treatment. Each set of two-layer composite film rolls is sent into a constant temperature curing chamber. The temperature of the curing chamber is uniformly set to 40-50℃, and the relative humidity is ≤60%. The curing time is divided into two levels: 24 hours for conventional film layer combinations and 36 hours for composite films with greater thickness and more functional layers. Through long-term constant temperature curing, the adhesive is completely cured, releasing the internal stress generated by multi-layer film composite and preventing the finished packaging bags from delamination, curling, and delamination problems caused by film layer delamination during use, bending, and high and low temperature environments.

[0058] After curing, the interlayer peel strength of the composite film is sampled and tested. The peel strength between any two layers of film is not less than 1.0N / 15mm. The peel is caused by tearing of the film substrate rather than separation of the adhesive layer, which is considered as qualified for composite. The adhesive preparation and composite curing process is designed around four key points: safety and non-toxicity, uniform coating, stress release, and strong adhesion. It not only meets the hygiene and safety requirements of pharmaceutical packaging, but also solves the common industry problem of easy delamination and degumming of multilayer composite films from the process level, ensuring the structural integrity of the composite packaging bag for long-term use.

[0059] Although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A moisture-proof and bacteriostatic traditional Chinese medicine composite packaging bag, characterized in that, The device includes an outer protective film layer (100), an intermediate buffer transition layer (200), a moisture barrier layer (300), an antibacterial functional layer (400), and an inner contact film layer (500). The outer protective film layer (100), intermediate buffer transition layer (200), moisture barrier layer (300), antibacterial functional layer (400), and inner contact film layer (500) are arranged from the outside to the inside. The outer protective film layer (100), intermediate buffer transition layer (200), moisture barrier layer (300), antibacterial functional layer (400), and inner contact film layer (500) are composite molded with food-grade adhesive. The intermediate buffer transition layer (200) is made of low-density polyethylene elastic film. The moisture barrier layer (300) is made of polyvinyl alcohol high barrier film and passivated aluminum foil film. The antibacterial functional layer (400) is based on food-grade polyolefin film. The inner contact film layer (500) is made of food-grade polyethylene film.

2. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 1, characterized in that: The outer protective film is made of biaxially oriented polypropylene (BOPP) film. The BOPP film roll is subjected to surface dust removal and static electricity removal treatment. Then, a corona treatment device is used to perform high-intensity corona activation on the inner surface of the BOPP film. The corona power is controlled at 800-1200W and the processing speed is 15-25m / min. This creates a micro-uneven structure on the inner surface of the BOPP film, which improves the subsequent adhesion strength with the adhesive and intermediate buffer transition layer (200). At the same time, a matte wear-resistant coating and a weather-resistant protective coating are roller-coated on the outer surface of the BOPP film. The coating thickness of the matte wear-resistant coating and the weather-resistant protective coating is controlled at 5-10μm. After coating, the film is placed in a constant temperature oven and dried and cured at 60-70℃ for 20-30min to prevent the coating from peeling off or dripping.

3. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 2, characterized in that: The intermediate buffer transition layer (200) is made of low-density polyethylene elastic film, and the inner contact film layer (500) is made of food-grade polyethylene film. The low-density polyethylene elastic film and the food-grade polyethylene film are subjected to high-temperature impurity removal and stretching straightening treatment in sequence to remove the volatile additives and internal stresses remaining in the production process of the low-density polyethylene elastic film and the food-grade polyethylene film, so as to ensure the flexibility and flatness of the low-density polyethylene elastic film and the food-grade polyethylene film.

4. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 3, characterized in that: The moisture-proof barrier layer (300) is formed by combining a polyvinyl alcohol high barrier film and a passivated aluminum foil film. First, the aluminum foil film with a thickness of 6-12μm is subjected to double-sided passivation and anti-corrosion treatment. Then, it is combined with the polyvinyl alcohol high barrier film by hot pressing at 110-125℃ and 0.3-0.5MPa. At the same time, 20-50nm hydrophobic nano silica powder is uniformly incorporated into the polyvinyl alcohol high barrier film to improve the hydrophobic and water-blocking ability.

5. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 4, characterized in that: The antibacterial functional layer (400) uses food-grade polyolefin film as the substrate. During the melt extrusion stage, 1.2% to 2.5% by mass of organosilicon-coated modified nano-silver ion antibacterial powder and 1.8% to 3.2% by mass of artemisia, clove and forsythia compound plant-derived antibacterial extracts are added. The mixture is fully mixed by a twin-screw extruder to ensure that the antibacterial components are not agglomerated and are uniformly dispersed. After extrusion molding, the inner and outer surfaces of the food-grade polyolefin film are subjected to micro-textured embossing treatment.

6. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 5, characterized in that: The food-grade composite adhesive is prepared as follows: water-based polyurethane adhesive is selected as the base, and moisture-proof additives are added according to the usage environment. After stirring evenly, the solid content of the adhesive is controlled at 35% to 45%, and the viscosity is maintained at 1800 to 2500 mPa·s to ensure uniform coating and no harmful substances are released. After the above preparations are completed, the step-by-step composite process is started. Dry composite equipment is used to composite layer by layer in the order from the outside to the inside. The coating thickness of the outer protective film layer (100), the intermediate buffer transition layer (200), the moisture-proof barrier layer (300), the antibacterial functional layer (400), and the inner contact film layer (500) is controlled at 8 to 15 μm. The composite temperature is set at 75 to 90℃, and the composite linear speed is 10 to 20 m / min. After each two layers of film are composited, they are sent to the curing chamber and cured at 40 to 50℃ for 24 to 36 hours to eliminate the internal stress of the composite and prevent the film layers from delaminating and peeling.

7. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 6, characterized in that: Using high-speed slitting and bag-making equipment, the bags are cut to the set size and the sides are heat-sealed to form rectangular bags. Finally, a full range of finished product inspections are carried out, including film adhesion testing, water vapor transmission rate testing, oxygen transmission rate testing, antibacterial performance testing, and food and drug safety migration testing. Defective products that are delaminated, leaking, fail to meet antibacterial standards, or have the presence of harmful substance migration are rejected. Qualified products are sorted, packaged, and put into storage.

8. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 7, characterized in that: The finished moisture-proof and antibacterial Chinese medicine composite packaging bags, after being cut and sorted, are inspected manually with the aid of calipers and rulers. The visual inspection of the bag surface is conducted to ensure that there are no scratches, bubbles, pinholes, color differences, or coating peeling. The multi-layer film layers are free from delamination, curling, or degumming. The side heat seals are continuous, uniform, and without any gaps. Measuring tools are used to measure the overall dimensions of the bag, the thickness of each film layer, and the width of the heat seal. All dimensions meet the design tolerance requirements.

9. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 8, characterized in that: Using professional water vapor transmission rate testers and oxygen transmission rate testers, the overall water vapor transmission rate and oxygen transmission rate of the packaging bag were tested according to national standard methods. The water vapor transmission rate was required to be ≤3g / (m²・24h) and the oxygen transmission rate was required to be ≤0.5cm³ / (m²・24h・atm). At the same time, a high humidity environment simulation test was conducted, in which the packaging bag was placed in a constant temperature and humidity chamber with a relative humidity of 85% and a temperature of 25℃ for 90 consecutive days. The barrier performance was tested regularly, and the performance degradation rate was required to be less than 5%.

10. The moisture-proof and antibacterial composite packaging bag for traditional Chinese medicine according to claim 8, characterized in that: For the antibacterial performance test, referring to the "Test Method for Antibacterial Performance of Antibacterial Plastics", three typical bacteria species for traditional Chinese medicine storage, namely Escherichia coli, Staphylococcus aureus, and Aspergillus niger, were selected for quantitative antibacterial testing. The bacterial solution was inoculated onto the inner surface of the packaging bag, and counted after being incubated at a constant temperature for 24 hours. The antibacterial rate of the three bacteria species was required to be no less than 90%. At the same time, a long-term antibacterial test was carried out. The antibacterial rate was retested after the sample was placed at room temperature for 6 months to ensure the long-term sustained release and stable performance of the antibacterial components.

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