What is PTFE?
PTFE (Polytetrafluoroethylene) also known as Teflon™ is a high-performance fluoropolymer renowned for its exceptional chemical resistance and ultra-low friction properties. PTFE is widely used in demanding industrial applications with extreme temperatures, corrosive environments and its low friction “non-stick” capabilities are critical. It offers great electrical insulation, little to no moisture absorption and excellent weather resistance, making it ideal for seals, gaskets, linings, bearings and build components that require low friction. While it sounds like the perfect plastic, trying to glue anything to PTFE is difficult to say the least.
Challenges with bonding PTFE
Bonding PTFE presents a unique challenge due to its extremely low surface energy, which prevents most adhesives from properly wetting the surface. As a result, PTFE has traditionally been considered difficult or impossible to bond in many applications. Manufacturers and fabricators have therefore relied on mechanical fastening methods such as rivets, hardware, ultrasonic welding, plastic welding and snap fits.
While these methods can be effective, they come with clear trade-offs. They are time consuming to design and assemble, add bulk and weight to finished parts, increase labour and tooling costs, introduce visible hardware and can create localised stress points that lead to fatigue or cracking over time.
NEXTITE has developed industrial adhesive solutions specifically engineered to bond polypropylene to itself and dissimilar substrates. With the correct surface preparation, polypropylene can be reliably bonded using advanced industrial adhesives such as methacrylates or cyanoacrylates (in combination with a primer).
Adhesive selection is application specific and depends on factors including bond strength, cure speed, environmental and chemical exposure, flexibility and impact resistance.
Which adhesives work?
Methacrylates (MMA) – NEXTITE AB206
NEXTITE AB206 is a two-part methyl methacrylate adhesive designed to structurally bond hard-to-glue plastics like polypropylene, polyethylene and PTFE without primers and minimal surface preparation. It delivers strong, chemical-resistant bonds to polyolefin’s, other plastics, metals and composites. Making it ideal for automotive, plastic assembly and industrial applications it is also ideal for bonding dissimilar surfaces.
|
Strengths |
Structural adhesive, multi material bonding, toughened, some gap filling, widely used in industry manufacturing and repair work, good chemical resistance |
|
Limitations |
Long cure time, not best for aesthetic bonding although possible |
Instant Adhesives (Cyanoacrylates) – NEXTITE SP901 Polyolefin Primer + Various NEXTITE Instant Adhesives
NEXTITE SP 901 is a surface primer for making polyolefins and other low surface energy materials suitable for bonding with NEXTITE Instant Adhesives. It is suitable to prime the notoriously difficult to bond surfaces such as polyethylene, polypropylene and polytetrafluoroethylene (PTFE). NEXTITE SP 901 works well with all our cyanoacrylate adhesives especially the faster fixture time ones.
|
Strengths |
Fast fixture, high shear strength, no mixing (single part), high strength even on small bond areas, aesthetic bond line possible |
|
Limitations |
Limited gap filling capacity <0.15mm, Low peel strength, Low Impact Strength |
|
Most Suitable |
NEXTITE 501 and NEXTITE 506 surface insensitive, fast curing variants provide the best results. Although, all NEXTITE Instant Adhesives can be used with NEXTITE SP901. |
What Industries is PTFE used in?
In manufacturing, PTFE is widely specified for its extreme temperature resistance, ultra-low friction surface and chemical inertness. It performs reliably in highly corrosive environments and maintains its properties across a very broad temperature range. PTFE is lightweight, nonstick and electrically insulating making it suitable for many industrial applications. It can be cut and machined however bonding Teflon™ requires specialised surface preparation and high-performance industrial adhesives due to its extremely low surface energy.
Common uses of PTFE
PTFE is used in many applications including:
- Seals and gaskets
- Chemical processing
- Bearings and Bushes
- Electrical Insulation and Cable Components
- Food Processing
- Pharmaceutical Equipment
Challenges with PTFE
- Extremely low surface energy, making it very difficult to bond
- Requires surface treatment
- Limited adhesive options compared to higher surface energy plastics
- Adhesive selection is critical for long term durability
Properties of PTFE
- Surface Energy: 18 mJ / m²
- Temperature Resistance: -200°C to 260°C
- Melting Point: 320°C
Surface Preparation
Proper surface preparation is critical to achieving a strong and reliable bond when working with PTFE. Begin by wiping the bonding area with NEXTITE PROPREP Surface Preparation Cleaner. This removes surface contaminants including dust, and oils that can interfere with bond strength. Allow the cleaner to fully evaporate before applying the suitable adhesive or primer.
Summary
Choosing the best industrial adhesive to bond PTFE comes down to understanding the application requirements and performance required from the joint.
If you would like to speak to our expert team about your next project, please contact us for tailored advice and product recommendations to suit your application.
Teflon™ is a trademark of The Chemours Company FC, LLC.