Needle Shield Corrosion Prevention via Rigid Plastic Extraction
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Solution Overview
Problem
Existing needle shields contribute to corrosion of syringe needles due to chloride leaching from the rubber components, leading to increased risk of corrosion under humid conditions and confinement.
Innovation Solution
A needle shield with a compliant material forming a hollow cavity that minimizes contact between the needle and the rubber, featuring a tapered design and controlled angle to reduce scrapping and confinement, thereby preventing chloride agglomeration and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the needle shield uses a soft rubber component to provide secure sealing connection, then the sealing performance is improved, but the risk of needle corrosion increases due to chloride leaching from the rubber
Solution Approach 1:
The patent removes the rubber component entirely from the needle shield design, replacing it with a fully rigid plastic construction. This extraction of the harmful rubber material eliminates the source of chloride leaching while maintaining the sealing function through alternative means such as tight-fitting geometric design and material properties of the rigid plastic.
Solution Approach 2:
The patent changes the material parameter from elastic rubber to rigid plastic, fundamentally altering the chemical composition to eliminate chloride content. This parameter change transforms the shield from a material prone to corrosion-causing leaching to one that is chemically inert and safe for needle contact.
2Strength
If the needle shield uses rigid component to provide protection against accidental needle sticks, then the protective function is improved, but the needle may be subject to corrosion under humid environment and local confinement
Solution Approach 1:
The patent extracts the rubber component that causes corrosion and replaces it with rigid plastic material. This substitution maintains the protective strength function while eliminating the harmful chemical interactions that lead to needle corrosion in confined humid environments.
Solution Approach 2:
The patent uses rigid plastic material that combines the protective strength properties needed for accident prevention with chemical inertness that prevents corrosion. This single-material solution integrates both required functions without the harmful effects of rubber-composite designs.
3Reliability
If the needle shield is designed with compliant rubber material to preserve sterility, then the sterility protection is improved, but chloride from the rubber can agglomerate on the needle leading to corrosion
Solution Approach 1:
The patent completely removes the rubber component from the needle shield, eliminating the source of chloride that causes agglomeration on the needle. The sterility preservation function is maintained through the rigid plastic material's inherent chemical stability and non-reactivity with the needle surface.
Solution Approach 2:
The patent changes the material composition parameter from rubber-containing compounds to pure rigid plastic, transforming the chemical properties to eliminate chloride content while maintaining the sterility protection through the material's inertness and密封 properties.
Data Source
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AI summary
Provided herein is a needle shield for use with a prefilled or prefillable syringe. The syringe includes a syringe assembly having a barrel with a barrel end portion at the distal end thereof, a needle having a proximal end fixedly inserted into the barrel end portion, and a needle shield mounted to the barrel via the barrel end portion, so as to be positioned over the needle. A plunger is received within a chamber of the barrel and is axially movable therein. The needle shield includes a compliant material at least partially defining a hollow cavity therein, the hollow cavity including a needle receiving portion within which the needle is positioned when the needle shield is mounted to the barrel, with a wall forming part of the needle receiving portion having an angle, α, between 8° and 90° relative to a longitudinal axis of the needle shield.