Plastic Container Piercing Area Wall Thickness Optimization
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Solution Overview
Problem
Existing plastic container products for medical use, such as injection vials and infusion bottles, face issues with particle contamination during piercing, leading to clogging and reduced infusion flow rates, and existing solutions either require complex and costly special cannulas or compromise on sterilization safety due to thin wall thickness or inadequate sealing.
Innovation Solution
A plastic container product designed for blow molding, filling, and sealing processes with a piercing area wall thickness of at least 0.3 mm and a tensile modulus less than 400 MPa mm, combined with a cap featuring an elastomeric sealing element that applies a surface pressure of at least 20 N/cm² during piercing, to minimize particle formation and ensure autoclave sterilization safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the container wall thickness in the piercing area is reduced to less than 0.254 mm, then particle formation during piercing is reduced, but sterilization safety is compromised due to leaks under autoclave conditions
Solution Approach 1:
The patent applies parameter changes by precisely controlling the wall thickness in the piercing area to be at least 0.254 mm but not exceed 0.508 mm, and by controlling the product of wall thickness and tensile modulus to be less than 400 MPa·mm. This optimized parameter range reduces particle formation while maintaining structural integrity during autoclave sterilization, resolving the contradiction between minimizing particles and ensuring sterilization safety.
2Object-generated harmful factors
If special needle geometries are used to reduce particle contamination, then particle formation is minimized, but device complexity and cost increase
Solution Approach 1:
The patent extracts the particle formation problem from the piercing device and relocates it to the container wall properties. By modifying the container wall characteristics (thickness and tensile modulus product) rather than the piercing needle geometry, the solution eliminates the need for complex special cannulas while still minimizing particle contamination.
Solution Approach 2:
The patent introduces an intermediary parameter - the product of wall thickness and tensile modulus - that mediates between the container structure and the piercing process. This intermediary parameter allows standard piercing devices to achieve low particle formation by controlling the container's mechanical properties rather than requiring specialized needles.
3Reliability
If the wall thickness is increased to ensure sterilization safety, then sterilization reliability is improved, but particle formation during piercing increases
Solution Approach 1:
The patent resolves this contradiction by changing the relevant parameters from simply increasing wall thickness to optimizing the product of wall thickness and tensile modulus. By controlling this combined parameter to be less than 400 MPa·mm while maintaining wall thickness of at least 0.254 mm, the container achieves both sterilization reliability and minimal particle formation during piercing.
Data Source
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AI summary
The invention relates to a plastic container product, in particular produced by the blow-molding, filling, and sealing method, having a container wall which can be pierced by means of a cannula in predefinable areas for the purpose of access to the container content. Said plastic container product is characterized in that, in order to avoid punched parts which arise when the container wall is pierced with a cannula, the mathematical product of the container wall thickness in the piercing area and the tensile modulus of the plastic material to ISO 527 is less than 400 MPa-mm, in particular preferably less than 300 MPa⋅mm.