Composite membrane with filtration function and production process thereof

Abstract

The application relates to the technical field of packaging film production, and particularly discloses a composite film with a filtering function and a production process thereof, which comprises an inner layer film, perforations are formed in the inner layer film, the perforations are used for intercepting solid residues in a packaging bag made of the composite film, so that an external brewing medium can penetrate into the packaging bag and be mixed with powder; an outer layer film is combined on the outer side of the inner layer film, the outer layer film is provided with a tearable structure in the area where the perforations are located, so that when force is applied along the tearable structure, the local outer layer film in the area where the tearable structure is located can be separated from the inner layer film and expose the perforations; a release medium layer is arranged between the outer layer film and the inner layer film, and the release medium layer covers at least the area where the perforations are located. In the application, the packaging bag made of the composite film can play a filtering role after being torn, and the solid residues in the product in the packaging bag are intercepted in the packaging bag.

Description

Technical Field

[0001] This application relates to the field of packaging film production technology, and in particular to a composite film with filtration function and its production process. Background Technology

[0002] In recent years, with the upgrading of the fast-moving consumer goods and food and beverage industries, many new types of instant beverage products have emerged on the market, such as specialty fruit teas, herbal health teas, drip bag blended coffees, and meal replacement powders. These products are characterized by their formulations often being a mixture of powder and solids, containing both easily dissolving fine powders and larger, hardened pieces that need to be discarded after brewing or are not suitable for direct consumption. Users need to tear open the packaging film, pour the entire product into the brewing medium, and then stir with a plastic stirring stick. Because the hardened pieces are directly immersed in the brewing medium, this affects the user's drinking experience and requires further improvement.

[0003] If filtration functionality is to be directly incorporated into the outer packaging of flexible products, the existing multilayer film composite system faces the following insurmountable technical challenges in actual manufacturing: First, in order to filter water flow and intercept debris, it is necessary to perforate the inside of the packaging film. However, the microporous array structure will severely damage the tensile stress and tear resistance of the inner membrane. The perforation creates dense stress concentration points, making the inner membrane extremely fragile.

[0004] Secondly, packaging films must maintain high moisture and oxygen barrier properties throughout the product's lifecycle, requiring extremely strong bonding between the film layers. In existing multi-layer easy-tear composite film technology, the bonding between film layers is typically a strong, integral adhesive. When a user forcefully tears open the outer film to expose the deeper structure, the immense tensile stress is directly transferred along the adhesive interface to the already weakened inner barrier layer, causing it and its microporous structure to be completely torn or even pulverized. This results in the complete failure of the filtration function and large-scale leakage of the internal powder. Summary of the Invention

[0005] In order to overcome the technical bottleneck that the weak layer of the packaging composite film is easily damaged and broken after being perforated by external force, and to achieve an integrated design that takes into account both packaging sealing and powder filtration function, this application provides a composite film with filtration function and its production process.

[0006] In a first aspect, this application provides a composite membrane with filtration function, employing the following technical solution: A composite membrane with filtration function includes an inner membrane with perforations for intercepting solid debris in a packaging bag made of the composite membrane, allowing external brewing medium to penetrate into the packaging bag and mix with powder located inside the packaging bag; an outer membrane, laminated to the outside of the inner membrane, having an easy-tear structure in the area where the perforations are located, the easy-tear structure being positioned at the boundary of the perforation area, the outer membrane and the inner membrane being in a peelable state at least in the perforation area, such that when force is applied along the easy-tear structure, a portion of the outer membrane in the area of ​​the easy-tear structure can detach from the inner membrane and expose the perforations; a release medium layer is provided between the outer membrane and the inner membrane, the release medium layer at least covering the area where the perforations are located.

[0007] By adopting the above technical solution, the long strip-shaped packaging bag made of this composite film has storage and filtration functions. During packaging bag production, the composite film is first rolled into a cylindrical shape and then heat-sealed. Next, the bottom of the cylindrical structure is sealed, the product is placed inside, and the top is sealed to complete the product packaging. When using the product, the user simply tears the outer film along the tear-resistant structure at the end outside the perforation to expose the perforation. Then, the perforated end is inserted into the brewing medium. The brewing medium then seeps into the packaging bag through the perforation and mixes with the powder inside, while solid residue remains inside the bag. After mixing, the packaging bag is removed from the brewing medium, removing the solid residue and preventing it from remaining in the brewing medium, thus ensuring a better drinking experience for the user.

[0008] The release medium layer functions to regulate the adhesive strength between the inner and outer membrane layers. A weak bonding interface is formed at the release medium layer. This interface is designed to maintain a stable bond between the two membranes during normal storage and transportation of the packaging bag, preventing accidental separation; however, it is significantly weaker than the bonding strength between other layers within the composite membrane (such as the bond between PET and AL membranes) and weaker than the tear strength of the HOPP or PET membrane material itself. Therefore, when the user tears the outer membrane along the pre-designed easy-tear structure, the tearing stress is preferentially released at this weak interface, allowing the outer membrane to peel off easily and completely from the PET membrane. The peeling process is smooth, providing a good user experience. Secondly, because the bonding between the inner membrane layers is very strong, and the PET membrane itself has high strength, the peeling stress will not be transmitted to or damage the structure of the inner membrane, thus ensuring the integrity of the perforated area and enabling reliable filtration. Finally, the presence of the release medium layer ensures a clear interface after peeling, preventing adhesive residue or uneven membrane layer delamination. This guarantees a smooth, foreign-free surface in the exposed perforated area, making it more hygienic to use.

[0009] In summary, the solution proposed in this application overcomes the technical bottleneck in the prior art where the weak layer of the packaging composite film is easily damaged and broken when torn by external force after being perforated. This allows the long strip-shaped packaging bag made from the composite film to have storage and filtration functions, thus ensuring the user's experience.

[0010] Optionally, the inner layer film comprises a heat-sealing film, an AL film, and a PET film laminated sequentially, with the heat-sealing film located on the inside when the packaging bag is made from the composite film; the outer layer film is a HOPP film laminated on the PET film; and the release medium layer is disposed between the outer layer film and the PET film.

[0011] By adopting the above technical solutions, the multi-layer composite structure constitutes an inner bag body that combines strength, barrier properties, and heat-sealing capabilities. The heat-sealing film, as the innermost layer, directly contacts the powder product, and its main function is to provide reliable heat-sealing performance. During the bag-making process, heat pressing melts and bonds this layer of material, forming a strong bag edge seal to ensure the airtightness of the packaging bag and prevent powder leakage or moisture absorption. Simultaneously, the heat-sealing film typically also possesses good flexibility, adapting to bag deformation. The AL film, as the intermediate barrier layer, is crucial for the long-term storage stability of the packaging. The AL film is made of aluminum foil, which has extremely high light-blocking, oxygen-blocking, and moisture-proof properties, providing better protection for sensitive powder products and helping to extend shelf life. The HOPP film, as the outermost layer, undertakes the functions of appearance, printing, and protection. The smooth surface and high transparency of the HOPP film make it ideal for printing exquisite patterns, text, and brand information, enhancing the product's appearance. Its good abrasion resistance protects the printed content from scratches during daily handling. More importantly, after uniaxial stretching, the molecular chains of HOPP film exhibit a higher degree of orientation in a specific direction. This makes it easier to achieve clean, linear tearing in that direction, providing an ideal material basis for the subsequent easy-tear line function. In summary, this composite structure of heat-sealing film, AL film, PET film, and HOPP film ensures the core storage function of the packaging bag while also laying a solid foundation for the easy-tear function of the outer film and the overall aesthetics of the packaging bag.

[0012] Optionally, the perforation is located at one end of the composite membrane along its length.

[0013] By adopting the above technical solution, the perforation is located at one end of the packaging bag, resulting in a mixing zone of moderate length, making it convenient for users to hold and mix. When the user immerses the perforated end into the liquid to begin mixing, the undissolved powder inside the packaging bag can be guided more directly and quickly to the perforated area and mixed with the external liquid through the perforation. This design helps to establish an effective powder delivery channel in the early stages of mixing, accelerating the overall dissolution process. In addition, concentrating the perforation at one end ensures that the main body of the packaging bag remains relatively intact after mixing, making it easy for users to squeeze or pour out the small amount of product remaining inside, reducing powder waste inside the bag, and improving user experience and product value.

[0014] Optionally, the composite film formed by combining the inner film and the outer film is used to make a packaging bag, and the end of the packaging bag with the perforation is used to be inserted into the brewing medium to form a stirring working part.

[0015] By adopting the above technical solution, the perforated end of the packaging bag is inserted into the brewing medium. Holding the packaging bag and stirring it accelerates the mixing of the powder and the brewing medium. This design eliminates the need for a separate stirring rod and its packaging, reducing the consumables required for production and the cumbersome operation and potential pollution problems caused by a separate stirring rod. While ensuring the normal storage function of the powder product inside, it also achieves environmentally friendly and convenient integrated brewing and stirring.

[0016] Optionally, the outer film has a tear-opening groove at the edge of the tearable structure.

[0017] By adopting the above technical solution, the tear-open groove provides users with a clear initial point of application, reducing the difficulty of tearing and improving the user experience, making the stirring function of the packaging bag easier to use. This design lowers the barrier to entry, increases the certainty and success rate of operation, and enables the stirring function of the packaging bag to be more widely used.

[0018] Optionally, multiple perforations are provided, and the multiple perforations are arranged in an array, with the diameter of the perforations being 0.5 to 2.0 mm.

[0019] By adopting the above technical solution, the aperture of the perforation is controlled between 0.5mm and 2.0mm, which can generate appropriate water flow shear force during stirring, effectively promoting powder dissolution. At the same time, it avoids the problem of excessive powder leakage before stirring due to excessively large aperture or water flow obstruction due to excessively small aperture, thus optimizing the stirring effect.

[0020] Secondly, this application provides a manufacturing process for preparing the composite membrane with filtration function as described in any of the above claims, comprising the following steps: Step S1, Initial film preparation: Prepare the inner layer film with a predetermined structure, wherein the release medium layer is provided on one side of the inner layer film; Step S2, Perforation: A plurality of through-holes are formed on the inner membrane; Step S3, Composite Molding: Provide the outer film, composite the inner film with the release medium layer on one side to the outer film, and process the tear-resistant structure on the outer film corresponding to the perforation area to form the composite film.

[0021] By adopting the above technical solution, the production process clearly defines the complete flow from membrane material preparation and functional structure processing to the final product. First, perforations are processed on the inner membrane, then a release medium layer is applied, and finally, the inner and outer membranes are laminated together. This ensures that the final product simultaneously possesses the storage function for the internal powder product and the filtration function during use. The entire process has a high degree of standardization, facilitating large-scale production and enabling the stable manufacture of packaging bags that integrate storage, filtration, and mixing.

[0022] Optionally, in step S1, the inner layer film is composed of a heat-sealing film on the inner surface, an AL film in the middle, and a PET film on the outer surface, which are sequentially laminated together.

[0023] By adopting the above technical solution, the multi-layer composite structure forms an inner bag that combines strength, barrier properties, and heat-sealing properties, which helps to ensure the effectiveness of the packaging bag.

[0024] Optionally, the tear-resistant structure is first processed on the outer membrane, and then the outer membrane with the tear-resistant structure is laminated with the inner membrane.

[0025] By adopting the above technical solution, this process sequence of tangenting followed by lamination is suitable for scenarios requiring high precision in the processing of easily tearable structures. Processing the easily tearable structure independently on the outer film first allows for more precise control of the tangent depth and shape, avoiding interlayer interference or deformation that may occur during post-lamination processing, thus ensuring the stability of the easily tearable structure's quality.

[0026] Optionally, the inner membrane and the outer membrane are first composited, and then the tear-resistant structure is processed on the outer membrane.

[0027] By adopting the above technical solution, this process sequence of first laminating and then cutting the lines is suitable for scenarios with high integration of production processes. First, the two films are laminated to form a stable composite material before the easy-tear lines are processed, which reduces production process changes, improves the efficiency of continuous production, and is especially suitable for high-speed production lines.

[0028] In summary, this application includes the following beneficial technical effects: 1. By cleverly combining perforations and an easy-tear structure into the composite membrane, the packaging bag made from the composite membrane of this application can function as a filter after being torn, intercepting solid debris from the product inside the packaging bag. Because of the release medium layer, tearing the packaging bag does not easily damage the perforated area of ​​the inner membrane, ensuring the normal operation of the packaging bag's filtering function.

[0029] 2. Inserting the packaging bag into the brewing medium allows the bag to stir the medium during the brewing process, accelerating the mixing of the powder and the medium. This eliminates the need for an additional stirring rod and its packaging, achieving an environmentally friendly, low-cost, and more convenient integrated solution.

[0030] 3. The array of multiple perforations allows water to flow through numerous small holes, generating uniform shear force that effectively promotes powder dissolution and ensures high mixing efficiency. The design of placing the perforations at one end of the bag also makes the grip and mixing action more ergonomic and helps reduce powder residue inside the packaging.

[0031] 4. The production process provided in this application is clear and feasible, and two main processing sequences for easy-tear threads are given: cutting the threads before laminating and laminating before cutting the threads. These two process routes are adapted to different production scenarios with extreme precision requirements and high efficiency requirements, respectively, enabling the design to achieve large-scale, high-quality production through mature processing technology, and possessing strong industrialization potential. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the unfolded structure of the composite membrane with filtration function in Embodiment 1 of this application; Figure 2 This is a schematic diagram of the structure of the composite membrane with filtration function in Embodiment 1 of this application after it is wound and sealed at the bottom. Figure 3 This is a cross-sectional view of a composite membrane with filtration function according to an embodiment of this application; Figure 4 This is a process flow diagram of the production process in an embodiment of this application.

[0033] Reference numerals: 1. Inner film; 11. Heat-sealing film; 12. AL film; 13. PET film; 2. Outer film; 3. Perforation; 4. Tearable structure; 5. Release medium layer; 6. Tear-open groove; 7. Cavity. Detailed Implementation

[0034] The following combination Figures 1-4 This application will be described in further detail.

[0035] Example 1: This application discloses a composite membrane with filtration function. (Refer to...) Figure 1 and Figure 2 The composite membrane with filtration function is used to make long, narrow packaging bags. These bags can be used to hold products in a powder-residue mixture, such as specialty fruit teas, herbal health teas, drip bag blended coffees, and meal replacement powders. During processing, the composite membrane is first wound up, with the two ends overlapping in the width direction. The overlapping ends are then heat-sealed to form a long, narrow cylindrical structure. Next, the bottom of this cylindrical structure is sealed, creating a cavity 7 inside to hold the product. The product is then filled into the cavity 7, and the top is sealed to form a complete packaging bag.

[0036] Reference Figure 3 The composite membrane with filtration function includes an inner layer and an outer layer membrane 2 laminated to one side of the inner layer membrane 1. The inner layer membrane 1 adopts a multi-layer composite structure, which includes a heat-sealing film 11, an AL film 12, and a PET film 13 sequentially from the inside to the outside of the packaging bag. Among them, the heat-sealing film 11 is a polyethylene (PE) film, a cast polypropylene (CPP) film, or a HOPP film. In this embodiment, the heat-sealing film 11 is a HOPP film, facing the inside of the packaging bag, and is the key layer for achieving bag sealing. The AL film 12 is an aluminum foil film, located in the center, providing excellent light blocking, oxygen blocking, and moisture-proof properties to ensure the long-term storage stability of the powder. The PET film 13 is a polyester film, located on the outermost side, providing mechanical strength and support for the inner layer membrane 1. The outer layer membrane 2 is a HOPP film, namely a high-transparency uniaxially stretched polypropylene film. The outer layer membrane 2 is laminated to the surface of the PET film 13 of the inner layer membrane 1. The outer layer membrane 2 has good printability, surface gloss, and abrasion resistance.

[0037] The core reason for specifically choosing HOPP film for the outer layer in this solution is that HOPP film undergoes deep stretching along a specific direction during its production process, resulting in a highly regular orientation of its polymer molecular chains. This polymer orientation structure endows HOPP film with excellent straight-line tearability in a specific direction. When the user applies peeling force along the tearable structure 4 and the tear groove 6 on its edge, the material properties of HOPP film itself ensure that the torn edge remains straight and smooth, effectively preventing the tear trajectory from deviating, skewing, or jagged, thus ensuring that the perforation area 3 on the inner film 1 can be accurately exposed, improving the user experience and structural reliability.

[0038] Reference Figure 1 and Figure 2The inner membrane 1 has multiple through-holes 3 at one end along its length. These through-holes 3 are arranged in an array, and their diameters range from 0.5 to 2.0 mm. On the outer membrane 2, corresponding to the areas where the through-holes 3 are located, there are easy-tear structures 4, which are easy-tear lines or easy-tear openings. The trajectory of the easy-tear structures 4 surrounds the outer contour of the array of through-holes 3. A tear-opening groove 6 is also provided on the outer membrane 2 at the starting edge of the easy-tear structures 4 to provide a starting point for tearing.

[0039] In use, the user locates the tear-open groove 6 and tears open the outer film 2, which is fitted onto the outside of the perforation 3, along the tear-resistant structure 4. After tearing, the bottom end of the outer film 2 is removed, and the pre-set perforation 3 area on the inner film 1 is fully exposed. At this point, the user can insert the end of the packaging bag with the perforation 3 into the brewing medium. Solid debris in the packaging bag can be trapped inside, while the powder in the packaging bag can be mixed with the brewing medium. Simultaneously, the user can hold the end of the packaging bag away from the perforation 3 and use this part of the composite film with the perforation 3 as a stirring rod, inserting it into the cup to stir the brewing medium. The perforation 3 allows liquid to flow through during stirring, generating eddies that effectively promote powder dissolution.

[0040] To ensure that the bottom of the outer film 2 can be easily and completely peeled off by the user without damaging the structure of the inner film 1, a release medium layer 5 is printed on the side of the PET film 13 of the inner film 1 near the outer film 2. The release medium layer 5 uses a release agent, such as a silicone release agent. The release medium layer 5 enables a controllable bonding force between the PET film 13 and the outer film 2, thus facilitating quick separation during tearing.

[0041] In other embodiments, the release medium layer 5 is not limited to a silicone release agent coating, but can also be any other equivalent structure capable of achieving a peelable bond between the outer film 2 and the inner film 1 in the perforation 3 region. For example, the release medium layer 5 can be a release ink printed in this region, such as matte varnish or release varnish, which blocks effective adhesion of adhesive through its low surface tension or non-adhesive properties. Alternatively, the release medium layer 5 can also be a very thin solid release sheet pre-placed in this region, such as Teflon tape or an untreated film, which physically separates the two films during lamination.

[0042] It should be noted that although the perforations 3 on the inner membrane 1 penetrate the middle AL membrane 12, the design of this embodiment will not cause the internal powder to become damp and deteriorate, thus meeting the requirements for safe storage of industrial products. On the one hand, the outermost outer membrane 2 and the PET membrane 13 of the inner membrane 1 have a stable and dense interlayer adhesion through the above-mentioned composite process. Before the outer membrane 2 is torn, the outer membrane 2 is tightly and seamlessly laid flat against the periphery of the area where the perforations 3 are located by means of this adhesion, completely sealing all the perforations 3 from the outside, spontaneously forming a second physical barrier, effectively preventing powder leakage and greatly slowing down the intrusion of external oxygen and moisture. On the other hand, the pore size of the multiple perforations 3 is controlled within a small range of 0.5 to 2.0 mm. The tiny openings limit the material exchange interface, and combined with the barrier properties of the HOPP film that covers the entire periphery, the impact on shelf life is almost eliminated during the static storage period.

[0043] In this embodiment, the pore size of the perforation 3 is set to a range of 0.5–2.0 mm to accommodate the particle size and solubility characteristics of different types of brewing products. As a specific implementation, the following specific pore size specifications are preferred in this application: Specification 1: The pore size is 0.5mm. This specification is suitable for fine powder products, such as high-mesh cold brew coffee powder. With a pore size of 0.5mm, it can achieve the retention of powder, preventing undissolved powder from overflowing in large quantities when it is first put into water, while maintaining the minimum capillary and shear fluid permeability required for the liquid to penetrate into the packaging bag.

[0044] Specification 2: The aperture is 1.2mm. This specification is the optimal solution for conventional comprehensive products. The 1.2mm aperture can achieve the best balance between the turbulence and scouring caused by the water flow and the dissolution rate of the internal powder. It has low resistance during stirring and the residue is not easy to leak out.

[0045] Specification 3: The pore size is 2.0mm. This large pore size can effectively peel off and break down powder clumps when agitated rapidly. Moreover, 2.0mm is still smaller than the size boundary of solid debris in most products, which can better ensure the interception and filtration effect.

[0046] The implementation principle of Example 1 is as follows: First, a release medium layer 5 is printed on one side of the PET film 13. Then, the side of the PET film 13 away from the release medium layer 5 is laminated with the AL film 12 and the heat-sealing film 11 to form the inner layer film 1. Multiple arrayed perforations 3 are provided at one end of the inner layer film 1, penetrating the inner layer film 1. Then, an easy-tear structure 4 is processed on the outer layer film 2. The processed outer layer film 2 is laminated with the side of the inner layer film 1 with the release medium layer 5 to form a composite film. The composite film is wound and sealed to form a cylindrical structure. The bottom end of the cylindrical structure is sealed, the product is added into the cylindrical structure, and then the top end of the cylindrical structure is sealed, completing the product packaging process.

[0047] When the user needs to brew, identify the tear groove 6 and easy-tear structure 4 on the outer film 2 at one end of the packaging bag. Tear open the end of the outer film 2 that is fitted outside the perforation 3 along the easy-tear structure 4. Since the easy-tear structure 4 is set around the area of ​​the perforation 3, the tearing action will completely remove the part of the outer film 2 covering the perforation 3, thereby exposing the area of ​​the perforation 3 of the inner film 1. Then, insert the end of the packaging bag with the perforation 3 into the water, tear open the top seal of the packaging bag to create a natural air intake. At this time, the solid particles inside the packaging bag can be trapped inside the packaging bag, and the powder inside the packaging bag can be mixed with the brewing medium. At the same time, the long strip of packaging bag can be stirred by hand, which can accelerate the mixing of the powder inside the packaging bag with the brewing medium. After mixing and brewing, the packaging bag can be removed. At this time, the solid particles can be removed together, thereby avoiding the solid particles remaining in the brewing medium and affecting the user's drinking experience. The whole process can be completed quickly, and the stirring rod is the packaging bag itself, without the need to unpack additional accessories.

[0048] Reference Figure 4 This application also discloses a manufacturing process for preparing the aforementioned composite membrane with filtration function. The specific steps of this process are as follows: Step S1, Initial Film Formulation: First, a release medium layer 5 is printed or coated on one side of the PET film 13, and then the inner layer film 1 is prepared. The inner layer film 1 is made by multi-layer co-extrusion or composite process, and includes a heat-sealing film 11 on the inner surface, an aluminum foil film 12 in the middle, and a PET film 13 with the release medium layer 5 printed on the outer surface. The heat-sealing film 11 is located on the inside of the future packaging bag and is used for the final heat sealing of the bag; the aluminum foil layer provides a barrier; and the PET film 13 serves as a support.

[0049] Step S2, Hole making: Using a punching die or laser drilling equipment, an array of through holes 3 are processed at one end of the inner layer film 1.

[0050] Step S3, Composite Molding: This embodiment adopts a sequence of dicing followed by lamination. First, an outer film 2 is provided. Then, on the outer film 2, using laser scribing or mechanical indentation equipment, an easy-tear structure 4 is processed in the area corresponding to the perforation 3 of the inner film 1; tear-open grooves 6 are processed at the edges of the easy-tear structure 4. Next, the outer film 2 with the processed easy-tear structure 4 is laminated to the surface of the PET film 13 coated with the release medium layer 5 using a dry lamination process. The release medium layer 5 is located between the two films to ensure that the outer film 2 and the PET film 13 can be easily peeled off subsequently.

[0051] Example 2: This example discloses another production process, which differs from the production process in Example 1 in the execution order of step S3.

[0052] Steps S1 and S2 are the same as in Example 1: an inner layer membrane 1 with a multilayer structure is prepared, a release medium layer 5 is printed or coated on one side of the inner layer membrane 1, and perforations 3 are processed on the inner layer membrane 1.

[0053] Step S3, Composite Molding: In this embodiment, the order of lamination followed by tearing is adopted. First, an outer layer film 2 is provided, and the outer layer film 2 is laminated with the surface of the PET film 13 on the side with the release medium layer 5 to form a composite film with an unprocessed easy-tear structure 4. Then, on the laminated composite film, an easy-tear structure 4 is processed from the outer layer film 2 side, corresponding to the area of ​​the perforation 3 of the inner layer film 1. The easy-tear structure 4 is an easy-tear line. The laser energy needs to be controlled to ensure that the easy-tear line is formed only on the outer layer film 2 and the release medium layer 5 without damaging the structure of the inner layer film 1.

[0054] The above are optional embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A composite membrane with filtration function, characterized in that, include: Inner membrane (1), the inner membrane (1) has perforations (3) for intercepting solid debris in the packaging bag made of the composite membrane, so that the external foaming medium can penetrate into the packaging bag and mix with the powder inside the packaging bag; An outer membrane (2) is laminated to the outside of the inner membrane (1). An easy-tear structure (4) is provided on the outer membrane (2) in the area where the perforation (3) is located. The easy-tear structure (4) is provided at the boundary of the area where the perforation (3) is located. The outer membrane (2) and the inner membrane (1) are in a peelable state at least in the area where the perforation (3) is located, so that when force is applied along the easy-tear structure (4), a part of the outer membrane (2) in the area where the easy-tear structure (4) is located can be detached from the inner membrane (1) and the perforation (3) is exposed. A release medium layer (5) is provided between the outer membrane (2) and the inner membrane (1), and the release medium layer (5) at least covers the area where the perforation (3) is located.

2. The composite membrane with filtration function according to claim 1, characterized in that: The inner layer film (1) comprises a heat-sealing film (11), an AL film (12) and a PET film (13) laminated in sequence. When the composite film is used to make a packaging bag, the heat-sealing film (11) is located on the inside. The outer layer film (2) is a HOPP film laminated on the PET film (13). The release medium layer (5) is disposed between the outer layer film (2) and the PET film (13).

3. A composite membrane with filtration function according to claim 1, characterized in that: The perforation (3) is located at one end of the composite membrane along its length.

4. A composite membrane with filtration function according to claim 3, characterized in that: The composite film formed by combining the inner membrane (1) and the outer membrane (2) is used to make a packaging bag, and the end of the packaging bag with the perforation (3) is used to be inserted into the brewing medium to form a stirring working part.

5. A composite membrane with filtration function according to claim 1, characterized in that: The outer membrane (2) has a tear-opening groove (6) at the edge of the easily tearable structure (4).

6. A composite membrane with filtration function according to claim 1, characterized in that: The perforation (3) is provided in multiple ways, and the multiple perforations (3) are arranged in an array. The diameter of the perforation (3) is 0.5 to 2.0 mm.

7. A production process, characterized in that: The method for preparing a composite membrane with filtration function as described in any one of claims 1 to 6 comprises the following steps: Step S1, Initial film preparation: Prepare the inner layer film (1) with a predetermined structure, wherein the release medium layer (5) is provided on one side of the inner layer film (1); Step S2, Hole making: A plurality of through holes (3) are formed on the inner layer film (1); Step S3, Composite molding: Provide the outer film (2), combine the inner film (1) with the outer film (2) on the side where the release medium layer (5) is provided, and process the tearable structure (4) on the outer film (2) in the area corresponding to the perforation (3) to form the composite film.

8. A production process according to claim 7, characterized in that: In step S1, the inner layer film (1) is composed of a heat-sealing film (11) on the inner surface, an AL film (12) in the middle, and a PET film (13) on the outer surface in sequence.

9. A production process according to claim 7, characterized in that: In step S3, the processing sequence is as follows: first, the tearable structure (4) is processed on the outer membrane (2), and then the outer membrane (2) with the tearable structure (4) is combined with the inner membrane (1).

10. A production process according to claim 7, characterized in that: In step S3, the processing sequence is as follows: first, the inner layer membrane (1) is combined with the outer layer membrane (2), and then the easily tearable structure (4) is processed on the outer layer membrane (2).

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