Bio-Based PVC Flexible Tube for Low Plasticizer Leaching
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Solution Overview
Problem
Conventional flexible tubes used in medical and household applications, made from plasticized polyvinyl chloride, can leach phthalate-based plasticizers into fluids, posing a risk of exposure to consumers and raising health concerns.
Innovation Solution
A flexible tube composed of a polyvinyl chloride with a molecular weight greater than 1.0 inherent viscosity, combined with a bio-based plasticizer such as fully hydrogenated castor oil, which is non-toxic and provides improved mechanical properties and reduced extractables in fluid environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional plasticized polyvinyl chloride is used to make flexible tubes, then the tubes achieve the required flexibility and mechanical properties, but phthalate-based plasticizers can leach into fluids, posing health risks
Solution Approach 1:
The patent changes the chemical composition parameter by substituting conventional phthalate-based plasticizers with alternative plasticizers that have different chemical structures and properties. This parameter change eliminates the harmful leaching effect while preserving the flexibility function through careful selection of plasticizers with appropriate molecular weight, polarity, and compatibility characteristics.
Solution Approach 2:
The patent employs composite material formulation by combining polyvinyl chloride with specific ratios of plasticizers, lubricants, and stabilizers. This composite approach creates a synergistic system where the plasticizer molecules are optimally distributed within the PVC matrix, reducing leaching tendency while maintaining flexibility through the combined effects of multiple components rather than relying on a single substance.
2Strength
If high molecular weight polyvinyl chloride with IV greater than 1.0 is used, then mechanical strength is improved, but processing difficulty increases
Solution Approach 1:
The patent optimizes the inherent viscosity parameter of PVC within a specific range (greater than 1.0) to balance strength and processability. By controlling this molecular weight parameter and combining it with appropriate plasticizer content and processing conditions, the formulation achieves both high mechanical strength and acceptable processing characteristics.
Solution Approach 2:
The patent uses plasticizers as intermediary substances that facilitate processing of high molecular weight PVC. These plasticizers act as lubricants and molecular spacers during processing, reducing intermolecular friction and enabling easier flow and forming operations despite the high viscosity of the base polymer, thereby mediating between the conflicting requirements of strength and processability.
Data Source
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AI summary
A flexible tube includes a polymer composition of a poly vinyl chloride having a molecular weight greater than about 1.0 inherent viscosity (IV) and a bio-based plasticizer. Further, a method of forming a flexible tube is provided. The method includes compounding a poly vinyl chloride having a molecular weight greater than about 1.0 inherent viscosity (IV) with a bio-based plasticizer to form a polymer composition and extruding the polymer composition into the flexible tube.