Styrene Butadiene Block Copolymer Medical Drip Chambers
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Solution Overview
Problem
Current polymer materials for medical devices, such as drip chambers, face challenges in achieving a balance of properties like high softness, temperature resistance, and processability, often requiring plasticizers that compromise heat stability and transparency, while also needing to avoid the drawbacks of plasticized PVC, such as migration of harmful substances and environmental impact.
Innovation Solution
A polymer composition comprising a defined vinyl aromatic hydrocarbon/conjugated diene copolymer, specifically a styrene butadiene block copolymer, with a specific ratio of hard and soft blocks, elastomeric and non-elastomeric thermoplastic polymers, and a demolding additive, which provides optimized melt flow rate, heat stability, and Shore D hardness without the need for plasticizers, ensuring excellent processability and thermoforming behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plasticizers are added to improve softness and flexibility, then Shore D hardness decreases and flexibility increases, but heat stability (Vicat temperature) and transparency deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by using a specific block copolymer structure with defined hard and soft blocks, molecular weight ranges, and block ratios. This intrinsic material parameter change achieves softness and flexibility without requiring external plasticizers, thereby maintaining heat stability and transparency.
Solution Approach 2:
The patent employs a composite block copolymer system combining hard blocks (polystyrene) and soft blocks (polybutadiene) in specific ratios. This composite structure at the molecular level provides both rigidity and flexibility inherently, eliminating the need for plasticizers that would compromise heat stability and transparency.
2Ease of operation
If plasticizers are added to improve softness and flexibility, then Shore D hardness decreases, but transparency and heat stability are compromised
Solution Approach 1:
The patent modifies the polymer's molecular structure parameters by controlling the block copolymer composition, molecular weight, and architecture. This intrinsic change provides softness through the soft blocks while maintaining optical clarity, avoiding the transparency degradation caused by plasticizer additives.
3Ease of manufacture
If demolding agents are added to improve demolding properties, then ease of manufacture increases, but heat stability (Vicat temperature) decreases
Solution Approach 1:
The patent optimizes the polymer composition parameters including block copolymer ratios, molecular weight distribution, and crystallinity. These parameter changes inherently improve demolding properties through better melt flow and cavity release, eliminating the need for demolding agents that would lower heat stability.
4Productivity
If melt flow rate is increased to improve processability and cavity filling, then productivity increases, but Shore D hardness and structural integrity may be compromised
Solution Approach 1:
The patent adjusts the polymer's rheological parameters by controlling the block copolymer composition and molecular weight. This optimization enables high melt flow rates for improved processability while the block copolymer structure itself provides the structural integrity through its hard and soft block architecture.
Data Source
AI summary
The present invention relates to transparent and flexible styrene butadiene copolymer compositions having high softness and temperature resistance as well as good processability, and the process for their preparation. Further, the invention is directed to shaped articles produced from the inventive polymer composition, and the use of said polymer composition for preparing moldings, in particular for medical applications, in particular medical drip chambers.