PTFE (polytetrafluoroethylene)

Uniquely Kashima

Characteristics of PTFE1 Characteristics of PTFE2
Characteristics of PTFE3 Characteristics of PTFE4

PTFE (polytetrafluoroethylene) is a material with special features which make it extremely popular for plastic bearings. 

(See tables below.)

Overview of PTFE

PTFE is a kind of Teflon (commonly known as Teflon R polytetrafluoroethylene).
(“TEFLON” is a registered trademark of DuPont.)

It is very popular, so we are extremely familiar with it and its properties.

Originally, this material was called “tetrafluoroethylene resin”, or sometimes “polytetrafluoroethylene” (i.e., PTFE).

This plastic has been around a while. Accidentally discovered in 1938 by Dr. Plunkett at DuPont, it is a polymer made from fluorine and two carbon atoms. It was trademarked as “TEFLON” in 1944 and commercialized by DuPont. Now, it is in practically every home and business.

Because Teflon has wonderful characteristics like low surface friction, resistance to corrosion, and high resistance to heat, it is often used to coat surfaces. (Everyone knows about frying pans).

Various use cases:

  • Cooking utensils (frying pans, Teflon coatings)
  • Vehicle parts (such as bearings)
  • Coating of electrical wires (precision electronic equipment)
  • Roofing materials (Tokyo Dome)
  • Medical equipment (artificial blood vessels, medicine bottles)
  • Food equipment (Neri stirring machines)

Features of PTFE

  • Heat characteristics: can withstand a wide temperature range of -196 ℃ ~ 260 ℃
  • Electrical characteristics: provides the most excellent insulation among the plastic family
  • Chemical characteristics: highly resistant to acids and alkalis; does not get swollen or damaged, and is also stable in organic chemicals
  • Moisture characteristics: water absorption rate is 0%
  • Friction characteristics: coefficient of friction is lower than the very low coefficient of friction of ice
  • Bonding characteristics: other materials are very unlikely to stick

Possessing such special characteristics, while also having a higher coefficient of linear thermal expansion at the same time, it has a combination of features that make it soft and easy to change dimensions.

If you wish to use PTFE as a machine part, the characteristics described above, such as softness and easy dimensional change, can be a concern.

In order to improve these points, it is possible to add a filler to PTFE.

Moreover, it must be noted that adding a filler to PTFE increases the wear characteristics.

Filler material can be carbon, glass, or something similar.

Kashima Bearings thoughtfully advises, carefully proposes and skillfully manufactures products that effectively and efficiently satisfy the needs and desires of our customers by taking advantage of the unique characteristics of PTFE, such as:

  • Chemical resistance: terrific where powerful chemicals such as sulfuric acid, hydrochloric acid, ammonia, hydrogen fluoride, etc. are used
  • Non-stickiness: perfect where contamination caused by adherence of particles are a serious problem (e.g., food production lines); great benefit during cleaning

Highly Recommended   Recommended
Not Recommended  × Do Not Use

Material Call
symbol
Dry Irregular
moisture
In water /
In sea-water
Vapor Chemical Non-
magnetic
Insulating
Acid Alkali Organic
solvent
Oil
PTFE PT ×
PTG ×
PTE
PTN

NOTE: For chemicals, please consult us regarding the type and concentration, etc. of such.

Temperature Resistance of PTFE

Best Recommended   Highly Recommended   Recommended 
Not Recommended  × Do Not Use

Material Call
symbol
Temperature
-190℃~ -100℃~ -50℃~ -20℃~ Room
temperature
~60℃
~120℃ ~200℃ ~350℃
PTFE PT ×
PTG ×
PTE ×

NOTE: the shape of the bearing will change due to such temperatures.

For more information about tolerances and other issues, download a catalogue from here.

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