Film-coated rubber plug film body structure

Abstract

The utility model relates to the technical field of medicinal packaging products, specifically relates to a film body structure for being combined with rubber matrix, including film material body, its key lies in, the surface of film material body for being used for increasing the friction force microcosmic rough structure that contacts with rubber is provided, the microcosmic rough structure is continuous or intermittent concave -convex texture, specifically can be shown as grid, undulating, dot matrix or their combination, the utility model constructs the friction structure of physics on the contact surface of film material and rubber, greatly increases the binding force and the anti -displacement ability between both, in the rubber plug vulcanization forming process, can effectively restrain the relative sliding between film material and rubber matrix, thereby significantly reduces the incidence of " partial film " defect, improves product yield and encapsulation reliability, the structure is simple, easy to industrialized production, can synergistic effect with the existing optimization mould scheme, realizes better anti -partial film effect.

Description

Technical Field

[0001] This utility model relates to the field of pharmaceutical packaging technology, specifically to a coated rubber stopper structure for composite with a rubber matrix. Background Technology

[0002] Laminated rubber stoppers are an important component in modern pharmaceutical packaging. They consist of an inert film (such as a fluoropolymer film) laminated onto the surface of a rubber matrix, effectively preventing the migration of components from the rubber into the liquid medicine, thus ensuring the stability and safety of the drug. However, ensuring that there is no relative displacement between the film and the rubber matrix (i.e., "film misalignment") during the vulcanization process of the stopper has been a long-standing technical challenge.

[0003] As disclosed in the background document CN112008934A, the industry mainly solves the problem of film deviation by optimizing the mold structure. This patent sets both the first cavity for forming the crown of the rubber stopper and the second cavity for forming the neck in the lower mold core, and uses the protrusions of the upper and lower mold cores to clamp the rubber sheet, thereby restricting the flow direction and range of the rubber in the mold cavity, thus reducing the film deviation caused by the rubber flow to a certain extent.

[0004] However, the inventors recognized that simply restricting the macroscopic flow of rubber through mold structure was insufficient to completely eliminate film deviation. Under the high temperature and pressure of the vulcanization process, rubber exhibits fluidity, and microscopic relative slippage can still occur between it and the smooth film surface. The accumulation of this microscopic slippage can also lead to film deviation in the final product, affecting the yield. Therefore, a solution is needed that enhances the bonding stability between the film material and the rubber, starting from the film material itself. Utility Model Content

[0005] Purpose of the utility model: The technical problem to be solved by this utility model is to overcome the defect in the prior art where the membrane material and rubber may be misaligned due to microscopic relative displacement during the vulcanization process of the coated rubber stopper, and to provide a membrane structure of the coated rubber stopper that can effectively increase the friction between the membrane material and the rubber and suppress relative displacement from the membrane structure itself.

[0006] Technical solution: A membrane structure for a coated rubber stopper includes a membrane body, the key feature of which is that at least one surface of the membrane body is an adhesive surface for bonding with rubber, and the adhesive surface is provided with a micro-rough structure to increase its surface friction coefficient.

[0007] Preferably, the micro-rough structure is a continuous or discontinuous texture.

[0008] Preferably, the micro-rough structure is a mesh-like structure, which is composed of crisscrossing grooves or protrusions.

[0009] Preferably, the micro-rough structure is a wavy structure, which is composed of continuous or discontinuous peaks and troughs.

[0010] Preferably, the micro-rough structure is a lattice structure, which is composed of regularly or irregularly arranged concave or convex dots.

[0011] Preferably, the depth or height of the micro-rough structure is 1 μm to 50 μm. This size range provides effective frictional resistance without being too abrupt to puncture the film or affect its barrier properties.

[0012] Preferably, the membrane material is made of one of the following: polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and fluorinated ethylene propylene copolymer (FEP). These materials have good chemical inertness and are suitable for pharmaceutical packaging.

[0013] Preferably, the thickness of the membrane material body is 10μm to 200μm.

[0014] The technical solution of this utility model has the following advantages:

[0015] 1. The membrane structure of the coated rubber stopper provided by this utility model transforms the originally smooth contact interface into a physically interlocking interface with numerous microscopic "anchor points" or "grooves" by setting a microscopic rough structure on the contact surface (bonding surface) between the membrane material and the rubber. This greatly increases the mechanical interlocking effect of the uncured rubber flowing into the interior of the microstructure and curing during the vulcanization process, thereby significantly improving the bonding strength and shear displacement resistance between the membrane material and the rubber matrix, and fundamentally suppressing the formation of deviated membranes.

[0016] 2. The micro-rough structure design of this utility model is diverse, such as grid, wave, dot matrix, etc., and can be selected and optimized according to different rubber stopper shapes, rubber formulations and process conditions, making it widely applicable.

[0017] 3. The membrane structure of this utility model can form a synergistic effect with the optimized mold scheme in patents such as CN112008934A. The mold restricts the flow of rubber and positions the film from a macroscopic perspective, while this scheme enhances the bonding force at the microscopic interface. The combination of the two can more effectively solve the film deviation problem from both macroscopic and microscopic levels, further improving product yield and consistency.

[0018] 4. This membrane structure can be achieved through mature thin film processing technology, such as using pressure rollers with specific textures during membrane extrusion molding, or performing subsequent embossing, laser etching, chemical etching, and other treatments on the flat membrane material, which makes it easy to achieve industrial production and quality control. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the membrane material body and the bonding surface of this utility model.

[0020] Figure 2 This is a schematic diagram (grid-like) of the membrane structure provided in Embodiment 1 of this utility model.

[0021] Figure 3 This is a schematic diagram (wavy) of the membrane structure provided in Embodiment 2 of this utility model.

[0022] Figure 4 This is a schematic diagram (lattice-shaped) of the membrane structure provided in Embodiment 3 of this utility model.

[0023] Figure reference numerals: membrane body 10, bonding surface 20, mesh structure 21, wavy structure 22, dot matrix structure 23. Detailed Implementation

[0024] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0027] Example 1:

[0028] This embodiment describes a membrane structure for a coated rubber stopper, such as... Figure 1 and Figure 2 As shown. The membrane structure includes a membrane body 10, which may be made of PTFE and has a thickness of approximately 50 μm. One surface of the membrane body 10 is an adhesive surface 11 for bonding with rubber. On this adhesive surface 11, a mesh structure 21 is formed as a micro-rough structure 20 by an embossing process. The mesh structure 21 is composed of uniformly distributed ridges, with a width of approximately 5 μm and a height of approximately 10 μm. The mesh unit is approximately a square with a side length of 30 μm. When this membrane material is pressed with an uncured rubber sheet, the rubber flows into the recessed parts of the mesh under pressure and temperature. After curing, a strong mechanical interlock is formed, effectively preventing relative sliding between the two.

[0029] Example 2:

[0030] This embodiment describes another coated rubber stopper membrane structure, such as Figure 3 As shown. The difference from Example 1 is that its micro-rough structure 20 is a wavy structure 22. This wavy structure 22 is formed simultaneously during the extrusion of the ETFE film using a pressure roller with a wavy texture. The height difference between the crests and troughs (i.e., the structural depth) is approximately 15 μm, and the wavelength is approximately 40 μm. This continuous wavy structure provides isotropic resistance to displacement and exhibits good resistance to the flow of rubber in all directions.

[0031] Example 3:

[0032] This embodiment describes yet another coated rubber stopper membrane structure, such as Figure 4 As shown, its micro-rough structure 20 is a lattice structure 23. This structure is formed on the bonding surface 11 of the PFA film material using laser etching technology. The lattice consists of regularly arranged circular dimples with a diameter of approximately 8 μm and a depth of approximately 5 μm, with a center-to-center spacing of approximately 20 μm. This lattice structure ensures sufficient friction area while having minimal impact on the original mechanical properties of the film material.

[0033] Application example:

[0034] The membrane structure of this utility model is applied to the process of forming rubber stoppers using the optimized mold disclosed in CN112008934A.

[0035] First, a film-coated sheet is prepared by combining a film material with a micro-rough structure 20, as described in Examples 1, 2, or 3, with a raw rubber sheet. This film-coated sheet is then coaxially pressed with a positioning sheet to form an assembly, which is placed into the first cavity of the lower mold core. Subsequently, a top sheet can be laid on the assembly.

[0036] Next, the upper and lower mold cores are pressed together. During this process, the first protrusion of the upper mold core moves downward and works together with the second protrusion of the lower mold core to clamp the film sheet, positioning sheet, and top sheet (if used). Because the film bonding surface 11 of the film sheet has a micro-rough structure 20, the static friction between it and the adjacent rubber sheet (positioning sheet or its own rubber layer) is much greater than that of a smooth film, which greatly suppresses the small displacement of the film caused by rubber flow during the mold closing pressure and subsequent vulcanization.

[0037] Finally, vulcanization molding is performed. The rubber flows within the mold cavity and fills all cavities, while simultaneously embedding tightly into the micro-rough structure 20 of the film material, forming a strong mechanical bond. After vulcanization, the mold is opened and the product is removed. After punching, the final coated rubber stopper is obtained. The film material of this stopper is tightly bonded to the rubber, with precise positioning and no film deviation.

[0038] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A membrane-coated rubber stopper structure, comprising a membrane body (10), characterized in that: At least one surface of the membrane body (10) is an adhesive surface (11) for bonding with rubber, and the adhesive surface (11) is provided with a micro-rough structure (20) to increase its surface friction coefficient.

2. The membrane structure of a coated rubber stopper according to claim 1, characterized in that: The micro-rough structure (20) is a continuous or discontinuous texture.

3. The membrane structure of a coated rubber stopper according to claim 2, characterized in that: The micro-rough structure (20) is a mesh structure (21), which is composed of crisscrossing grooves or protrusions.

4. The membrane structure of a coated rubber stopper according to claim 2, characterized in that: The micro-rough structure (20) is a wave-like structure (22), which is composed of continuous or discontinuous peaks and troughs.

5. The membrane structure of a coated rubber stopper according to claim 2, characterized in that: The micro-rough structure (20) is a lattice structure (23), which is composed of regularly or irregularly arranged concave or convex points.

6. A membrane structure for a coated rubber stopper according to any one of claims 3 to 5, characterized in that: The depth or height of the micro-rough structure (20) is 1 μm to 50 μm.

7. The membrane structure of a coated rubber stopper according to claim 1, characterized in that: The membrane body (10) is made of one of the following: polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, and fluorinated ethylene propylene copolymer.

8. The membrane structure of a coated rubber stopper according to claim 1, characterized in that: The thickness of the membrane body (10) is 10μm to 200μm.

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