PI, Mylar, Nomex, PEEK and Fluoropolymers
Insulation Tubing Material Comparison: PI, Mylar, Nomex, PEEK and Fluoropolymers
No single insulation tubing material is best for every design. Polyimide, polyester film, aramid paper, PEEK and fluoropolymers solve different combinations of thermal, electrical, mechanical, chemical and manufacturing problems. Engineers should compare the finished tube construction and test conditions, not select from a headline temperature or dielectric value.
In this comparison
- Quick comparison
- Polyimide tubing
- Mylar polyester tubing
- Nomex aramid paper tubing
- PEEK tubing
- Fluoropolymer tubing
- Selection framework
Quick Engineering Comparison
| Material family | Typical reason to shortlist | Construction options | Selection caution |
|---|---|---|---|
| Polyimide (PI) | Thin-wall electrical insulation, heat exposure, dimensional precision | Dip-coated, extruded or wound depending on grade and supplier process | Moisture, hydrolysis, flexing and grade/process effects require review |
| Polyester film (Mylar-type) | Cost-effective film insulation and wound sleeving | Flat or spiral wound, sometimes heat-shrink construction | Temperature class, seam, adhesive and shrink behavior are construction-specific |
| Aramid paper (Nomex-type) | Electrical insulation systems needing paper-based thermal performance | Wound paper tube, laminated or composite construction | Moisture, edge durability, bond and wall build affect the tube |
| PEEK | Mechanical strength, wear, heat and demanding fluid/mechanical service | Primarily extruded tube and machined/converter forms | Cost, stiffness, process window and application-specific chemical data |
| PTFE/FEP/PVDF | Chemical resistance, electrical insulation or fluid handling | Extruded and selected formed/converting options | Each fluoropolymer differs in temperature, clarity, stiffness, joining and permeation |
This table is a screening framework, not a specification. Values depend on grade, wall, process, test method and service conditions.
When to Consider Polyimide Tubing
Polyimide tubing is commonly evaluated when the assembly needs a thin insulation wall, elevated-temperature capability and controlled small dimensions. It can support sensor, motor, probe and compact electronic applications where space is limited. The exact result depends on whether the tube is dip coated, extruded or wound and on the polymer grade.
Ask how wall thickness, pinholes, concentricity, mandrel removal, cure and cut-end quality are controlled. Do not assume a polyimide film trademark or resin datasheet represents the finished tube’s dielectric or mechanical performance.
When to Consider Mylar-Type Polyester Tubing
Polyester film tubing is often used for electrical separation, bolt or fastener sleeving, wound insulation and applications where a film-based construction offers a practical cost/performance balance. Flat or spiral winding can produce different seam patterns, overlap and wall builds.
Confirm the actual polyester film grade, adhesive or bonding system, temperature class, shrink behavior, seam orientation and moisture conditions. “Mylar” is a trademark used for specific polyester films; the supplied material identity should be stated accurately.
When to Consider Nomex-Type Aramid Paper Tubing
Aramid paper tubing can be shortlisted for motors, transformers and other electrical insulation systems that use paper-based materials. It may be wound as a tube or incorporated into a laminate. The system performance depends on paper grade, density, wall build, bond, moisture conditioning and interaction with varnish or impregnation.
Request evidence for the exact construction rather than relying only on the paper supplier’s typical data. Edge fraying, seam integrity, roundness and compression behavior may be as important as the base paper.
When to Consider PEEK Tubing
PEEK is considered when mechanical strength, wear resistance, dimensional stability and heat performance are required together. It can suit demanding equipment, sensor, aerospace, automotive, electrical and fluid applications, subject to grade and validation.
PEEK is usually a higher-cost choice, so use it where its combined properties solve a real design constraint. Review stiffness, bend radius, extrusion capability, chemical medium, pressure or load, sterilization or cleaning cycle and the required regulatory evidence.
When to Consider Fluoropolymer Tubing
PTFE is often screened for chemical inertness, low friction and electrical insulation; FEP for clearer fluid paths and melt processability; and PVDF for greater stiffness and industrial fluid systems. These materials are not interchangeable.
For fluid service, include chemical concentration, temperature, pressure, vacuum, permeation sensitivity and fittings. For electrical service, include voltage, wall, abrasion, flame requirement and the applicable standard. Review the detailed PTFE, FEP and PVDF tubing comparison before selecting a grade.
A Five-Factor Selection Framework
- Thermal: continuous, peak, cycling and hot-load conditions.
- Electrical or fluid: voltage system and test standard, or medium, pressure and permeation.
- Mechanical: stiffness, flexibility, abrasion, vibration, compression and bend radius.
- Geometry and process: ID, OD, wall, tolerance, seam, supplied length and assembly method.
- Qualification: material identity, declarations, test reports, lot traceability and change control.
Use the six-step tubing selection guide to turn these factors into an RFQ. If two materials appear equivalent, compare total qualification and assembly risk rather than unit price alone.
Common Comparison Errors
- Comparing a finished tube value with a raw film or resin typical value.
- Using maximum temperature without time, load or test context.
- Ignoring seams, adhesives, coating layers and winding overlap.
- Treating chemical resistance as proof of low permeation or pressure capability.
- Calling a product UL, FDA, RoHS or REACH compliant without product-specific evidence and scope.
Frequently Asked Questions
Is polyimide tubing always better than polyester tubing?
No. Polyimide may suit thinner walls or higher-temperature designs, while polyester film tubing may offer a better cost and process fit in less demanding conditions. Compare the finished construction, environment, tolerance and qualification requirements.
Can Nomex paper data be used as a tube specification?
Base-paper data helps screen the material, but a wound tube also depends on grade, layers, bond, seam, moisture, wall and manufacturing quality. Specify and test the finished tube characteristics that control the application.
When is PEEK justified?
PEEK is most defensible when its mechanical, wear, thermal or chemical properties solve a constraint that lower-cost materials cannot meet. Include qualification and processing cost in the comparison, not only raw-material price.
Which fluoropolymer is best for a clear fluid line?
FEP is often the first candidate when visual monitoring matters, but clarity depends on grade, wall, diameter and finish. Chemical, temperature, pressure and permeation requirements still need validation with an actual-size sample.
Request a Material and Process Review
Send WELLELE the application, drawing, operating environment and qualification requirements. WELLELE can compare feasible material and process routes subject to verified data and customer testing in the final assembly.
