Thin PTFE Tube High Elongation Extrusion
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Solution Overview
Problem
PTFE tubes with thin thickness face challenges in achieving both high tensile strength and elongation, as existing methods either compromise on tensile strength for elongation or vice versa, making them unsuitable for applications requiring both properties.
Innovation Solution
A PTFE tube with a thickness of 0.1 mm or less, featuring a tensile elongation at break of 350% or more and a melting energy of 0.6 J/g or more, achieved through the use of fine PTFE powder, an organic solvent with high lubricity, and controlled extrusion processes that minimize fibrillation and maximize fibril entanglement, resulting in a tube with enhanced tensile strength and elongation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If paste extrusion forming is used to manufacture PTFE tube, then manufacturing capability is improved, but tube thickness cannot be reduced to thin specifications
Solution Approach 1:
The patent changes the physical and chemical parameters of the PTFE material by using fine PTFE powder (average particle diameter 0.03-0.1 mm) instead of conventional coarse powder, and controls the extrusion temperature (20-100°C) and pressure parameters to achieve both thin wall formation and high strength. This parameter optimization resolves the contradiction between manufacturability and thin wall capability.
2Volume of moving object
If dipping method is used to form thin PTFE tube, then tube thickness is reduced, but tensile strength becomes weak
Solution Approach 1:
The patent fundamentally changes the material parameters by using ultra-fine PTFE powder with controlled particle size distribution and specific surface area (0.5-2.0 m²/g), combined with optimized paste composition (organic solvent content 10-30 wt%). These parameter changes enable the extruded tube to achieve thin wall thickness while maintaining high tensile strength through improved molecular orientation and reduced defects.
3Strength
If extension is performed to reduce thickness, then tensile strength increases, but tensile elongation at break is reduced
Solution Approach 1:
The patent performs preliminary action by optimizing the extrusion process parameters (temperature, pressure, speed) and paste composition before the tube is formed, creating a microstructure with fine fibrils and uniform density. This preliminary optimization of the base structure eliminates the need for excessive extension, allowing the tube to maintain both high strength and high elongation at break without the trade-off.
4Strength
If fine PTFE powder is used with controlled extrusion, then tensile strength and elongation are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes key parameters including PTFE powder particle size (0.03-0.1 mm), specific surface area (0.5-2.0 m²/g), organic solvent content (10-30 wt%), extrusion temperature (20-100°C), and extrusion pressure. By precisely controlling these parameters, the process achieves high performance tubes with standardized manufacturing procedures, balancing improved tensile strength and elongation against manufacturing complexity.
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 resulting PTFE tube exhibits a high tensile strength of 50 N/mm2 or more at 10 mm displacement and 70 N/mm2 or more at 20 mm displacement, along with a tensile elongation at break of 450% or more, making it suitable for applications like catheter manufacturing where both properties are critical.
Implementation Method 1
paste extrusion forming on the core wire
Implementation Method 2
an organic solvent with high lubricity
Implementation Method 3
the tube is extended in a longitudinal direction so as to reduce the thickness
Data Source
AI summary
A polytetrafluoroethylene tube is provided and has a thickness of 0.1 mm or less, a tensile elongation at break of 350% or more, and a melting energy of 0.6 J/g or more which is calculated from an endothermic peak at 370° C.±5° C. in a procedure of increasing a temperature in differential scanning calorimetry (DSC).