PTFE
(Polytetrafluoroethylene )
|
| General information |
Name :
Polytetrafluoroethylene (PTFE )
Chemical Formula : --[- CF2
– CF2 -]-- n
Formula weight 0.5-1.0 million
|
| Physical & Chemical Characteristics |
PTFE has good heat-resistance , can be used for a long time under
260 °C high temperature , or temporarily under – 268 °C . It will
decompose slowly and give out toxic gas when heated to 415 °C . It
can bear any other chemicals except melting sodium and gaseous fluoride
and do not change even in boiling chloronitric acid., especially its
comprehensive property : excellent self–lubricating property , wide
adoption for distant temperature range , perfect chemical stability
,anti-dirt , anti-coagulation , anti-aging , therefore , it is praised
by people as “ The king of plastic resin “
|
| Applications |
| PTFE is widely used in space flight , atomic energy , electronics
, machinery , chemical , textile , building , instrument , computer
, medical , equipment , light industry , including skived film and
sheet , gaskets , packing, mechanical seals , bridge or pipeline bearing
pads, shaft bearings, electrical insulators , piston rings , expansion
bellows , diaphragms ,and chemical linings . |
Physical Property
| No |
Item
|
Unit
|
Data sheet
|
Note |
|
1 |
Relative density
|
|
2.1 – 2.3
|
|
|
2 |
Melting point
|
°C |
327 +/- 5 |
|
|
3 |
Moisture |
% |
0.04 Max |
|
|
4 |
Hardness |
D |
50 – 65 |
Rockwell hardness
|
|
5 |
Highest temperature
allowed using . |
°C |
260 |
|
|
6 |
Coefficient
of static friction |
|
0.04 |
Between brakes
|
|
7 |
Yield tensile
strength
|
MPa |
7.252/2.744
|
250 °C / 100°C |
|
8 |
Modulus of
elasticity in static bending |
Mpa |
350 – 630
|
28 °C |
|
9 |
Coefficient
of thermal expansion |
10 –-5
/ °C |
5 – 10 |
|
|
10 |
Dielectric
constant
|
|
2.1 |
|
|
| Storage and Handling |
Performing is easiest when
the resin is uniformly between 21-27 C ( 70-80 F ) . As temperature
declines below this range , the resin will be increasingly difficult
to mold without cracks and problems with condensed moisture . High
temperatures inhibit flow and promote lumping . Storage condition
should be set accordingly .
Cleanliness is a critical requirement for successful use of PTFE
. The white resin and high sintering temperatures cause even very
small foreign particles to become visiblein finished moldings. Keep
resin drums closed and clean . Good housekeeping and careful handling
are essential .
|
|
