Thermoplastic Elastomer Medical Sealing Composition
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Solution Overview
Problem
Current sealing materials for medical use lack balanced properties such as flexibility, molding processability, visual transparency, damping property, and high-temperature compression set, as well as oxygen gas barrier and liquid leakage resistance, particularly after needlestick.
Innovation Solution
A styrene thermoplastic elastomer composition comprising a hydrogenated block copolymer with specific molecular weight and structure, combined with a softening agent and polyolefin resin, optimized for improved absorption and performance in medical sealing applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a hydrogenated block copolymer composition is used for medical sealing, then flexibility and elasticity are improved, but oxygen gas barrier property and liquid leakage resistance deteriorate
Solution Approach 1:
The patent employs a composite material system consisting of hydrogenated block copolymer (providing flexibility and elasticity) combined with specific polyolefin resins (providing oxygen gas barrier and liquid leakage resistance). This composite approach allows the sealing material to simultaneously achieve soft rubber-like flexibility and effective barrier properties that neither material could provide alone.
2Ease of manufacture
If softening agent is added to improve flexibility, then molding processability is improved, but retention of softening agent at high temperature deteriorates
Solution Approach 1:
The patent optimizes the chemical structure parameters of the hydrogenated block copolymer (specifically the ratio of polymer blocks and the degree of hydrogenation) to improve compatibility with the softening agent. This parameter optimization enhances the softening agent's retention at high temperatures while maintaining good molding processability, preventing excessive softening agent migration or degradation during sterilization and use.
3Strength
If molecular weight of block copolymer is increased to improve strength, then compression set at high temperature is improved, but molding processability deteriorates
Solution Approach 1:
The patent carefully controls the molecular weight parameters of the hydrogenated block copolymer within an optimal range, and adjusts the block composition ratios to balance mechanical strength and processability. This parameter optimization ensures sufficient compression set resistance while maintaining adequate melt flow for molding operations.
Solution Approach 2:
The patent combines hydrogenated block copolymer with specific polyolefin resins to create a composite system where the polyolefin component enhances molding processability by improving melt flow characteristics, while the hydrogenated block copolymer provides the necessary compression set resistance and elastic properties.
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 composition achieves excellent flexibility, molding processability, visual transparency, and high-temperature compression set, while providing enhanced oxygen gas barrier and liquid leakage resistance, making it suitable for medical sealing applications.
Implementation Method 1
the hydrogenated block copolymer has an excellent absorption property for the softening agent
Data Source
AI summary
Provided are a thermoplastic elastomer composition comprising: 100 parts by mass of (a) a hydrogenated block copolymer that is a hydrogenated product of a block copolymer containing (A) a polymer block containing a structural unit derived from an aromatic vinyl compound and (B) a polymer block containing a structural unit derived from isoprene or a mixture of isoprene and butadiene, having a total content of a 3,4-bond unit and a 1,2-bond unit of 45% or more, has a peak top molecular weight (Mp) obtained by gel permeation chromatograph in terms of polystyrene standard of from 250,000 to 500,000, and is in a form of powder having a bulk density of from 0.10 to 0.40 g/mL; from 10 to 300 parts by mass of (b) a softening agent; and from 5 to 200 parts by mass of (c) a polyolefin resin, and a molded article and a sealing material for medical use each comprising said thermoplastic elastomer composition.