Pharmaceutical Valve Seal Using Thermoplastic Elastomer
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Solution Overview
Problem
Existing pharmaceutical dispensing devices face challenges with seal materials that are not chemically compatible, have variable curing reactions, and result in residual by-products that can interfere with drug mechanisms and increase production costs due to prolonged extraction times.
Innovation Solution
A valve seal material comprising a polyolefin thermoplastic elastomer with isotactic propylene crystallinity, blended with a polymer having a higher melting point, which improves sealing characteristics and reduces leachables and extractables, allowing for reduced extraction processes and enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional elastomeric seal materials (such as nitrile rubber) are used in pharmaceutical dispensing devices, then good sealing performance and elasticity can be achieved, but residual by-products from curing reactions can migrate out and interfere with drug mechanisms
Solution Approach 1:
The patent removes the harmful curing agents and cross-linking by-products from the seal material system by using thermoplastic elastomers that do not require chemical curing. This extraction of the problematic curing process eliminates the source of residual by-products that could contaminate pharmaceutical products while maintaining the essential sealing function.
Solution Approach 2:
The patent changes the fundamental material parameter from chemically cross-linked elastomer to thermoplastic elastomer with physical entanglement structure. This parameter change transitions the material from requiring chemical curing to being processed and sealed through thermal mechanisms, thereby eliminating curing by-products while preserving elastomeric sealing properties.
2Strength
If peroxides are used to cure elastomers, then cross-linking and improved physical properties can be achieved, but the curing reaction can become variable affecting material properties and the products have to be removed as they can deteriorate elastomer properties
Solution Approach 1:
The patent replaces the chemical curing system (peroxides and cross-linking reactions) with a physical thermal system. Thermoplastic elastomers achieve their structural integrity through heat-induced melting and cooling, substituting chemical cross-linking with physical entanglement and crystallization, thereby eliminating variable chemical reactions and improving material consistency.
3Object-generated harmful factors
If extraction processes are prolonged to remove surface residues and by-products, then cleaner seal material can be achieved, but material properties deteriorate and production costs increase
Solution Approach 1:
The patent converts the potential harm of extraction processes into a benefit by selecting materials that inherently minimize the need for extraction. Thermoplastic elastomers are processed in a molten state where contaminants can be effectively removed, and their natural processing characteristics reduce the severity and duration of extraction needed, thereby preventing material property deterioration.
4Stability of the object's composition
If softer elastomeric components are used to achieve high elasticity, then favourable elasticity and Shore Hardness can be achieved, but the material requires cross-linking agents that leave residual by-products
Solution Approach 1:
The patent uses composite thermoplastic elastomer formulations that combine different polymer components to achieve the desired elasticity and Shore Hardness properties. These composite materials provide the necessary softness and elastic recovery without requiring chemical cross-linking, as the elastomeric properties arise from the physical structure of the thermoplastic blend rather than chemical bonds.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides improved sealing performance, reduced leakage, and increased thermal stability, maintaining elastomeric properties at elevated conditions, while minimizing the need for cross-linking agents and extraction processes, thus enhancing the reliability and efficiency of pharmaceutical dispensing devices.
Implementation Method 1
a polyolefin thermoplastic elastomer which comprises at least 80% of a propylene component with isotactic crystallinity
Implementation Method 2
a polymer selected from one or more of polypropylene, polyethylene and copolymers thereof, wherein the polymer has a melting point that is greater than the melting point of the thermoplastic elastomer
Data Source
AI summary
A seal for a valve for use in a pharmaceutical dispensing device, which seal is formed from a blend comprising: a thermoplastic elastomer including a propylene component with isotactic crystallinity; and a polymer selected from one or more of polypropylene, polyethylene and copolymers thereof.