At Adtech we spend our lives dealing with fluoroplastics,
and we tend to forget that to many other people they are unusual
and very uncommon plastics. So here for the layman is a simple
guide to what is what in the fluoroplastic world.
Fluoroplastics is a technical word given to a group of plastics where
the molecules contain carbon and fluorine. The plastic polythene
is a molecule consisting of a carbon chain with hydrogen atoms
attached.
PTFE is much the same but with the hydrogen atoms replaced with
fluorine atoms. The replacement of the hydrogen atoms with fluorine
atoms dramatically changes the properties of the material, and
fluoroplastics therefore tend to have special properties:-
Very high working temperatures. Non-stick characteristics. Very
high resistance to chemical and solvents. Very high electrical
resistance.
The more common members of the fluoroplastic family, with which
we work, are:-
PTFE (Poly Tetra Fluoro Ethylene)
Trade names:
, Fluon, Hostaflon.
PTFE is the grandfather of all fluoroplastics, it is the most
unusual and exhibits the best performance in terms of temperature
and chemical resistance, and non-stick properties. Its major disadvantage
is that it does not actually melt when heated and therefore is
difficult to process, and very unconventional techniques are needed
to mould, extrude and weld it.
FEP (Fluoro Ethylene Propylene)
Trade names:
Hostaflon
This is mainly manufactured by Du Pont Co. and was developed as
a melt processable version of PTFE. That
is, it can be processed by normal plastic methods. It has basically
similar properties to PTFE but a lower maximum operating temperature
of 200°C instead of 260°C.
PFA (Per Fluor Alkoxy)
PFA was developed as a high temperature version of FEP, generally
it has similar properties but it can be used at temperatures up
to 260°C. It is very expensive!
ETFE (Ethylene Tetra Fluoro Ethylene
Copolymer)
Trade Name: Tefzel
Du Pont developed this material as Tough Fluoropolymer.
It is a normal thermoplastic but it is much harder than PTFE &
FEP and similar in hardness to nylon, and is therefore used as
an Engineering Plastic. The improvement
in stiffness is paid for by reduced chemical resistance and working
temperature.
E-CTFE (Ethylene-Chloro Tri Fluoro
Ethylene)
Trade name: Halar
A tough plastic with similar properties to Tefzel. Used mainly
for its chemical resistance.
PVDF (Poly Vinylidene Fluoride)
Trade names: Kynar, Solef
Very hard plastic roughly comparable to Halar and relatively cheap
compared with other fluoroplastics. Good chemical resistance but
not as good as C-TFE and ETFE.
PVF (Polyvinyl Fluoride)
Trade name: Tedlar (R)
Again a hard tough fluoroplastic with limited chemical and temperature
resistance. Normally used as a film in gas bags, solar heating
panels, printing circuit laminating, etc.
The above information is very general and at Adtech we are very
keen to discuss the properties of these materials and to select
the best one for your application. There are many subtle differences
in these plastics, which if chosen carefully can give very great
price/performance benefits.
(R) PTFE, Tedlar
and Tefzel
are the registered Trade Marks of the DuPont Company
Keywords for Adtech products: Fluoropolymer
Fluon Hostaflon Halar Tefzel Tedlar KEL-F TFE PTFE FEP PFA ETFE
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