A cap for a pre-filled syringe

Abstract

The utility model relates to pre -filled syringe structure technical field, specifically disclose a cap for pre -filled syringe, including cap, the cap is composed by elastic inner lining and rigid outer cover, the elastic inner lining is nested in rigid outer cover inside, the rigid outer cover inboard middle part is equipped with middle annular boss, the elastic inner lining outer surface is equipped with the recess that matches with middle annular boss, forms double -sealed structure, the lower annular boss of the inner surface below of elastic inner lining is equipped with, is used for with syringe needle cylinder interface interference fit, the rigid outer cover outer wall is equipped with elastic sleeve, the elastic sleeve and the locking ring of syringe needle cylinder neck outside side adaptation lock, prevent cap from non - expected separation through the lock of elastic sleeve and locking ring, this pre -filled syringe cap double -sealed leak -proof, buckle limit prevents the loss, gas -guide groove helps the installation, contact surface is sterile, and the material is good and the cost is good, and the identification area is easy to identify, and the quality of medicine and use safety are convenient to guarantee.

Description

Technical Field

[0001] This utility model relates to the technical field of pre-filled syringe structure, and specifically discloses a protective cap for a pre-filled syringe. Background Technology

[0002] Pre-filled syringes, as integrated medical devices combining drug storage and injection functions, are widely used in the packaging of sterile drugs such as vaccines and biological agents. Their caps must simultaneously meet the requirements of sealing, contamination prevention, and ease of clinical operation. Existing patent CN220938711U discloses a cap for a pre-filled syringe, proposing a cap structure composed of a rubber cap and a plastic cap. The rubber cap's annular protrusion engages with the plastic cap's groove, and a hot-melt process is used to form a locking part at the upper end of the plastic cap to enhance the anti-detachment effect. However, this solution has the following technical bottlenecks:

[0003] The cap structure relies solely on a single snap-fit ​​structure (annular protrusion and groove) between rubber and plastic, lacking a multi-layered sealing design. This makes it difficult to address the risk of seal failure due to vibration or temperature differences during transportation or storage. The snap-fit ​​part needs to be formed through hot-melt processing, and improper control of process parameters (such as temperature and time) can easily lead to deformation of the plastic cap or heat damage to the rubber cap, increasing the defect rate. Furthermore, the surface of the rubber cap that comes into direct contact with the liquid medicine is not covered with a sterile layer, and long-term storage may lead to drug contamination due to material permeability.

[0004] To address the aforementioned issues, there is an urgent need for a new type of pre-filled syringe cap that, while ensuring anti-detachment performance, improves sealing reliability through structural optimization, simplifies the production process, and balances aseptic protection and user-friendliness. Utility Model Content

[0005] This utility model proposes a protective cap for a pre-filled syringe. The protective cap significantly improves the anti-leakage and anti-contamination capabilities and operational stability through a double sealing structure and an elastic sleeve anti-detachment design. At the same time, the air guide groove balances the air pressure to reduce the pull-out force, the sterile layer ensures the safety of the liquid, and the labeling area optimizes information accessibility. It combines high sealing performance, ease of use, and medical compliance.

[0006] This utility model is implemented as follows: a protective cap for a pre-filled syringe includes a protective cap, which is composed of an elastic inner liner and a rigid outer cover. The elastic inner liner is nested inside the rigid outer cover to provide mechanical support and anti-contamination protection.

[0007] The rigid outer cover has a central annular protrusion in the middle of its inner side, and the elastic inner liner has a groove on its outer surface that matches the central annular protrusion, forming a double sealing structure.

[0008] The inner surface of the elastic liner is provided with a lower annular protrusion for interference fit with the syringe barrel interface;

[0009] The rigid outer cover has an elastic sleeve on its outer wall. The elastic sleeve is adapted to and locked with the limiting ring on the outside of the syringe barrel neck. The locking of the elastic sleeve and the limiting ring prevents the cap from coming off unexpectedly.

[0010] As a preferred embodiment of the pre-filled syringe cap of this utility model, the cross-section of the lower annular protrusion is an asymmetrical trapezoid with the hypotenuse facing the opening of the cap, and the inclination angle between the hypotenuse and the axis of the elastic liner is 30°-45°.

[0011] As a preferred embodiment of the pre-filled syringe cap of this utility model, the top of the rigid outer cover is provided with an air guide groove, which penetrates the inner and outer surfaces of the elastic inner liner to balance the internal air pressure during cap installation.

[0012] As a preferred embodiment of the pre-filled syringe cap of this utility model, the contact surface between the elastic liner and the syringe barrel interface is covered with a sterile layer, which is made of irradiated cross-linked polyethylene or polytetrafluoroethylene.

[0013] As a preferred embodiment of the pre-filled syringe cap of this utility model, the rigid outer cover is made of polypropylene, cyclic olefin copolymer or polycarbonate, and its wall thickness is 0.5-1.2mm.

[0014] The elastic liner is made of silicone or medical-grade rubber.

[0015] As a preferred embodiment of the pre-filled syringe cap of this utility model, the outer surface of the rigid outer cover is provided with a marking area, which is a recessed or raised structure for accommodating a drug information label.

[0016] The beneficial effects of this utility model are:

[0017] 1. The dual-sealing structure (rigid outer cover and elastic inner liner) significantly reduces the risk of leakage or contamination, which is superior to the single snap-fit ​​solution; the locking mechanism of the elastic sleeve and the limiting ring does not require a hot-melt process, which simplifies production and improves the anti-detachment efficiency.

[0018] 2. The asymmetrical trapezoidal shape of the lower annular protrusion reduces insertion resistance while maintaining sealing force during extraction; the air guide groove eliminates air resistance during installation, ensuring the cap is in place in one go.

[0019] 3. The sterile layer is in direct contact with the drug solution to avoid chemical migration or biological contamination. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0022] Figure 2 for Figure 1 Schematic diagram of the AA-direction structure.

[0023] Figure 3 for Figure 2 A magnified structural diagram at point B in the middle.

[0024] The markings in the diagram are: 1. Protective cap; 2. Elastic liner; 3. Rigid outer cover; 4. Middle annular protrusion; 5. Groove; 6. Lower annular protrusion; 7. Elastic sleeve; 8. Air duct; 9. Sterile layer; 10. Identification area. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding its content. Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.

[0026] Please see Figure 1-3 A prefilled syringe cap includes a cap 1, which is composed of an elastic inner liner 2 and a rigid outer cover 3. The elastic inner liner 2 is nested inside the rigid outer cover 3 to provide mechanical support and protection against contamination.

[0027] The rigid outer cover 3 has a central annular protrusion 4 in the middle of its inner side, and the elastic inner liner 2 has a groove 5 on its outer surface that matches the central annular protrusion 4, forming a double sealing structure.

[0028] The inner surface of the elastic liner 2 is provided with a lower annular protrusion 6 for interference fit with the syringe barrel interface;

[0029] The outer wall of the rigid outer cover 3 is provided with an elastic sleeve 7. The elastic sleeve 7 is adapted to and locked with the limiting ring on the outside of the syringe neck. The locking of the elastic sleeve 7 and the limiting ring prevents the cap 1 from falling off unexpectedly.

[0030] In this embodiment: the elastic inner liner 2 is used for sealing with the syringe barrel interface, and the rigid outer cover 3 provides external protection and structural support. The two together constitute the overall structure of the cap 1; the middle annular protrusion 4 is located in the middle of the inner side of the rigid outer cover 3, and the groove 5 matches it on the outer surface of the elastic inner liner 2 to form a double sealing structure and enhance the sealing effect; the lower annular protrusion 6 is located below the inner surface of the elastic inner liner 2 and is press-fitted with the syringe barrel interface to achieve a preliminary seal and prevent drug leakage; the elastic sleeve 7 is on the outer wall of the rigid outer cover 3, and the limiting ring is on the outer side of the syringe barrel neck (the limiting ring is a flange structure that extends circumferentially around the syringe barrel neck). The elastic sleeve 7 is fitted on the limiting ring to prevent the cap 1 from falling off unexpectedly and to ensure connection stability (the limiting ring of the syringe barrel neck is also called a "flange" or "stop ring". This design is a common industry standard such as ISO7886-1. The limiting ring ensures that the needle and the syringe barrel are tightly connected to avoid leakage or loosening).

[0031] As a technical optimization of this utility model, the cross-section of the lower annular protrusion 6 is an asymmetrical trapezoid with the hypotenuse facing the opening direction of the cap 1, and the inclination angle between the hypotenuse and the axis of the elastic inner liner 2 is 30°-45°.

[0032] In this embodiment, the asymmetrical trapezoidal lower annular protrusion enhances the sealing effect between the lower annular protrusion 6 and the syringe barrel interface, making the connection between the cap 1 and the syringe tighter and effectively preventing drug leakage; at the same time, it facilitates the installation and removal of the cap 1 and improves the ease of use.

[0033] As a technical optimization of this utility model, the top of the rigid outer cover 3 is provided with an air guide groove 8, which penetrates the inner and outer surfaces of the elastic inner liner 2 and is used to balance the internal air pressure when the protective cap 1 is installed.

[0034] In this embodiment: During the installation of the protective cap 1 onto the syringe, the air guide groove 8 allows air to flow between the inside and outside of the protective cap 1, balancing the air pressure inside the protective cap 1; avoiding excessive resistance caused by the internal air pressure of the protective cap 1 being higher than the external air pressure, which would affect the installation of the protective cap 1; making the installation of the protective cap 1 smoother, reducing resistance and difficulties during the installation process, and improving installation efficiency; at the same time, ensuring that the protective cap 1 is installed in place, ensuring that the sealing performance is not affected by air pressure factors; the width of the air guide groove 8 is 0.1-0.3mm, the depth is 0.5-1mm, the elastic liner is made of high-resilience silicone, and the closed air guide groove 8 has no open channels, blocking external contaminants.

[0035] As a technical optimization of this utility model, the contact surface between the elastic liner 2 and the syringe barrel interface is covered with a sterile layer 9, which is made of irradiated cross-linked polyethylene or polytetrafluoroethylene.

[0036] In this embodiment: the sterile layer 9 covers the contact surface between the elastic liner 2 and the syringe barrel interface, isolating external microorganisms and impurities and preventing them from entering the syringe and contacting the drug; irradiated cross-linked polyethylene or polytetrafluoroethylene has good chemical stability and sterility, which can effectively maintain the sterility of the contact surface; it further improves the sterility of the connection between the cap 1 and the syringe, providing more reliable sterile protection for the drug, reducing the risk of drug contamination, and ensuring the quality and safety of the drug; the thickness of the sterile layer 9 is 0.05-0.2 mm.

[0037] As a technical optimization of this utility model, the rigid outer cover 3 is made of polypropylene, cyclic olefin copolymer or polycarbonate, and its wall thickness is 0.5-1.2mm.

[0038] The elastic liner 2 is made of silicone or medical-grade rubber.

[0039] In this embodiment: materials such as polypropylene, cyclic olefin copolymers, or polycarbonate have good rigidity, chemical stability, and impact resistance, and can withstand certain external forces to protect the internal elastic liner 2 and the syringe needle; a suitable wall thickness (0.5-1.2mm) can ensure that the rigid outer cover 3 has sufficient strength and rigidity, while controlling the weight and cost of the protective cap 1; this gives the rigid outer cover 3 good mechanical properties and chemical stability, effectively protecting the internal structure of the protective cap 1 and the syringe, extending the service life of the protective cap 1, and achieving a good balance between cost and performance;

[0040] Medical-grade rubber possesses excellent elasticity and flexibility, enabling it to fit tightly against the syringe barrel interface for a superior seal. Furthermore, these materials exhibit good biocompatibility, ensuring no adverse effects on the medication. They also guarantee a reliable seal between the elastic liner 2 and the syringe barrel interface, preventing medication leakage. Due to their biocompatibility, they ensure the safety and quality of the medication, preventing contamination or chemical reactions. Medical-grade rubber (such as butyl rubber) is also used.

[0041] As a technical optimization of this utility model, the outer surface of the rigid outer cover 3 is provided with a marking area 10, which is a recessed or raised structure used to accommodate drug information labels.

[0042] In this embodiment, the identification area 10 provides a suitable location and shape for placing the drug information label (the drug information label may contain important information such as drug name, specifications, production date, and expiration date), which makes it easier for users to identify and understand drug information and improves the accuracy and safety of drug use.

[0043] Working principle and usage process of this utility model:

[0044] Align the elastic inner liner 2 of the cap 1 with the syringe barrel interface, so that the lower annular protrusion 6 below the inner surface of the elastic inner liner 2 contacts the syringe barrel interface; then gently press the cap 1 to make the lower annular protrusion 6 and the syringe barrel interface interference fit, achieving a preliminary seal; during the pressing process, the air guide groove 8 at the top of the rigid outer cover 3 balances the internal air pressure of the cap 1, eliminates negative pressure resistance, and makes the installation smoother; when the cap 1 is almost fully installed, the elastic sleeve 7 on the outer wall of the rigid outer cover 3 is fitted onto the outer wall of the limiting ring on the outside of the syringe barrel neck, ensuring that the cap 1 is firmly installed on the syringe.

[0045] In the description of this utility model, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inner", "outer", "back", "middle", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this utility model.

[0046] However, the above are merely specific embodiments of this utility model and should not be construed as limiting the scope of implementation of this utility model. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of this utility model should still fall within the scope of the claims of this utility model.

Claims

1. A protective cap for a pre-filled syringe, comprising a protective cap (1), characterized in that: The protective cap (1) consists of an elastic inner liner (2) and a rigid outer cover (3). The elastic inner liner (2) is nested inside the rigid outer cover (3) to provide mechanical support and pollution protection. The rigid outer cover (3) has a central annular protrusion (4) in the middle of its inner side, and the elastic inner liner (2) has a groove (5) on its outer surface that matches the central annular protrusion (4), forming a double sealing structure; The elastic liner (2) has a lower annular protrusion (6) on the lower surface of its inner surface for interference fit with the syringe barrel interface; The rigid outer cover (3) has an elastic sleeve (7) on its outer wall. The elastic sleeve (7) is adapted to and locked with the limiting ring on the outside of the syringe barrel neck. The locking of the elastic sleeve (7) and the limiting ring prevents the cap (1) from falling off unexpectedly.

2. The protective cap for a pre-filled syringe according to claim 1, characterized in that: The cross section of the lower annular protrusion (6) is an asymmetrical trapezoid with the hypotenuse facing the opening of the cap (1), and the inclination angle between the hypotenuse and the axis of the elastic liner (2) is 30°-45°.

3. The protective cap for a pre-filled syringe according to claim 1, characterized in that: The top of the rigid outer cover (3) is provided with an air guide groove (8), which penetrates the inner and outer surfaces of the elastic inner liner (2) to balance the internal air pressure when the protective cap (1) is installed.

4. A protective cap for a pre-filled syringe according to claim 1, characterized in that: The contact surface between the elastic liner (2) and the syringe barrel interface is covered with a sterile layer (9), which is made of irradiated cross-linked polyethylene or polytetrafluoroethylene.

5. A protective cap for a pre-filled syringe according to claim 1, characterized in that: The rigid outer cover (3) is made of polypropylene, cyclic olefin copolymer or polycarbonate, and its wall thickness is 0.5-1.2 mm; The elastic liner (2) is made of silicone or medical-grade rubber.

6. A protective cap for a pre-filled syringe according to claim 1, characterized in that: The outer surface of the rigid outer cover (3) is provided with a marking area (10), which is a recessed or raised structure used to accommodate drug information labels.

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