What is PTFE? Pros and Cons of PTFE Coating?

11/01/2019

What is PTFE?

Polytetrafluoroethylene (PTFE) is a fluoroplastic that has a large number of industrial applications because of its many properties. One brand name for PTFE is Teflon®, which is well-known for its non-stick and heat-resistant properties.

The properties that make Polytetrafluoroethylene or PTFE so useful include:

  • Low friction
  • Inert
  • Self-cleaning
  • Durable
  • Effective across a wide range of temperatures
  • Non-flammable
  • Corrosive resistant
  • High electrical resistance

Its properties mean that we commonly know it as a non-stick coating for cookware (where its inertness & heat resistance are of particular importance.

PTFE was an accidental discovery, made in 1938 by a DuPont engineer who was working on refrigeration. That happy accident led to the creation of an industry.

PTFE Coating – meaning

PTFE coating is the process of coating items in PTFE. This is primarily done with two coats (a primer & a top coat). The PTFE coating is applied to areas where either a low friction, a corrosion-resistant or a dry lubricant is required.

To coat a product with PTFE, it will need to be prepared first of all. This can be done by degreasing or blasting the material (depending upon what it is) followed by the coating process. The coating will then be heated in an oven to form a dry coating. It will typically be 15 to 35 microns depending upon the customer specification and the number of coats of PTFE that have been applied.

There are different grades of coating depending upon the application (food-grade coating, for example requires a different application to an industrial grade).

Pros & Cons of PTFE Coating

The properties listed above show many of the properties that make PTFE a unique fluoropolymer. Because of these it has many advantages. The main ones are:

  • It is largely inert – this means it can be used to store reactive compounds or to line pipes that reactive agents will travel along
  • It is an excellent electrical insulator – this is why it is often used on printed circuit boards and electrical cables

There are some disadvantages to PTFE which give the product some limitations. For example, when overheated, it can release mildly toxic fumes. In addition, its abrasion-resistance is not as good as a number of other coatings and so abrasion resistance isn’t its primary advantage.

Disadvantages of the material are only relative to the application: in many ways, PTFE is a wonder material but it can’t be used for everything. Depending on the application, the following disadvantages can rule out the selection of PTFE:

  • Price – it is not a low-cost polymer
  • Production sizes – it is not easy to mass produce
  • It cannot be cemented
  • It can change shape under pressure
  • It is unweldable
  • It cannot withstand extremely high temperatures and melts at 326 celsius

 

If you have an application which you feel would benefit from such coating, please contact Chris at chris@holscot.com