There are many types of fluoropolymers available to support numerous applications across various industries.
This makes choosing the right o ring seals critical to ensuring that they help to optimise your applications performance.
The three main o-ring seals available are those of PTFE, FEP, and PFA. All of which carry out the same function primarily, to prevent leaks; however, there are subtle differences between these seals, which we will explore in more detail throughout this post.
PTFE, FEP, and PFA definition
PTFE
Polytetrafluoroethylene seals are one of the first synthetic fluoropolymers that were manufactured.
PTFE seals are ideal for creating coatings that have non-stick properties, making them most suitable and useful in food manufacturing applications, as liquids do not negatively impact or affect this particular material.
FEP
Fluorinated ethylene propylene also has non-stick properties like its PTFE counterpart, but FEP has a much softer makeup, which allows it to melt at lower temperatures.
Due to this factor, FEP seals are only suitable for certain applications, primarily, applications that are exposed to the elements.
FEP seals are transparent and resistant to sunlight and UV.
PFA
Perfluoroalkoxy (PFA) seals include a polymer that can be melt-processed. Its composition is that of a small chain length, which makes it incredibly durable and excellent for demanding applications.
PFA seals offer great chemical resistance, they have high purity, low stiffness, and they are resistant to weathering.
The lower melting temperature, when compared to PTFE seals, means that this seal does offer better insulation properties and UV resistance.
What are PTFE, FEP, and PFA?
PTFE vs FEP vs PFA – they are all common fluoroplastics, all made up of unique materials.
It is important to understand the differences between each of these materials to understand further which would be the correct material for your application.
Most fluoroplastics like PTFE, FEP, and PFA are suitable for:
- Medical applications and instruments
- Automotive sector
- Electrical applications
- Domestic applications.
PTFE, FEP, and PFA benefits:
- High working temperatures
- Non-stick characteristics
- They have low-friction surfaces
- High resistance to various chemicals
- High levels of electrical resistance.
Differences between PTFE, FEP, and PFA
PTFE (brand name Teflon) is one of the most unusual materials that consists of carbon and fluorine atoms. This particular type of seal offers the best performance when you require both temperature and chemical resistance, as well as non-stick properties.
They have a high operating temperature (in excess of 260 degrees Celsius), low friction properties, excellent durability, and they are translucent in colour, making them most suitable for electrical components.
PTFE seals are also the most cost-effective and are often considered unmatched when it comes to choosing the best seal.
Often found in gaskets, seals, and non-stick coating components.
However, PTFE is not a thermoplastic, so it will not melt when heated, making it difficult to process.
FEP – with thermal and chemical properties and offering biocompatibility, this o-ring comes with a lower operating temperature (200 degrees Celsius), making it easier to process, weld, and, in some instances, where required, remould.
This sealing type is extremely flexible, clear in colour, and is chemically and UV-resistant.
One of the main drawbacks of FEP o-rings however, is their lower operating temperature compared to PTFE seals.
PFA – offering excellent temperature stability, this o ring is melt processable as it provides a lower melt viscosity than PTFE. This means it has much higher welding and remoulding potential. PFA seals also have high permeability resistance, are available in high-purity grades, and are clear in colour.
If you require high purity and high-temperature resistance, along with greater flexibility during fabrication, then PFA seals will be the best option.
The main difference with PFA o rings is that they are more expensive to manufacture and purchase.
PFA seals are typically found in medical tubing, heat exchangers, semiconductor baskets, pumps, fittings, and valves.
While material choice is crucial, the seal’s configuration, such as whether you need axial seals or radial seals, also plays a vital role in ensuring optimal performance for your specific application requirements.
O ring suppliers Leeds
All three, PTFE, PFA, and FEP seals, are integral for applications in diverse industries. Offering high working-temperature resistance, non-stick properties, low-friction surfaces, high chemical and solvent resistance, and high electrical resistance, they are also incredibly versatile.
As one of the leading o ring suppliers in the UK, we work with businesses across various industries to provide the most appropriate seals and gaskets for the intended application.
If you’re looking for precision gaskets and seals, look no further.
Designing and manufacturing the highest-quality seals, our laser precision, attention to detail, and material choices mean that you can be assured of high quality and compatibility with and for your application.
We work with you to identify your needs and further understand which material seal would be the most appropriate for you.
To find out more or to speak to a member of the Specialist Sealing team today, call 01535 274 776 or email sales@specialistsealingproducts.co.uk
