PTFE (raw material)
PTFE-4 – is unique thermoplastic polymer having valuable physical and chemical properties determined by especially strong bond of carbon and fluorine atoms. Thanks to that PTFE-4 products have high thermal resistance, exceptional resistance to chemical action, perfect dielectric, mechanical, anti-adhesion and antifriction properties, and also have unique ability to preserve these characteristics even at high working pressure and within wide temperature range (from -269°C to +260°C). Meanwhile at overrun of these parameters just a slight reduction of physical and chemical properties of PTFE-4 products happens, and not the full loss of their chemical resistance.
Comparative characteristics of PTFE-4 various grades:
|
Quality parameter |
PTFE grade |
|||
|
F-4 |
F-4PN-90 |
F-4PN-40 |
F-4PN-20 |
|
|
Appearance |
Easily balling up powder, white color, without visible impurities |
|||
|
Mass share of water, %, not exceeding |
0,02 |
0,02 |
0,02 |
0,02 |
|
Density, g/cm3, not exceeding |
2,18-2,21 (depending on grade) |
2,19 |
2,19 |
2,19 |
|
Breaking strength of unhardened sample, MPa (kgf/cm2), not less |
26 (260) – 15 (150) (depending on grade) |
25 (255) |
25 (255) |
25 (255) |
|
Relative elongation at break of unhardened sample, %, not less |
350 – 150 (depending on grade) |
350 |
350 |
350 |
|
Electric strength, kW/mm, not less |
50 – 60 (depending on grade) |
- |
60 |
60 |
|
Average particle size, µm |
100-180 (not normed) |
46-135 |
21-45 |
6-20 |
At present over 60% of all PTFE production take the traditional PTFE, while the rest 40% is for PTFE based compositions. But still clean PTFE-4 offers good competition to many materials, including metal (stainless steel and enamels).
If it is necessary to increase technical and operational properties of PTFE-4, following composite materials may be added:
- powder-like;
- organic: soot, coke, coal, graphite;
- mineral: sitall, glass fiber, quartz, mica, ceramics, kaolin;
- metallic: silver, nickel, lead, copper, tin, bronze, aluminium;
- reinforcing (fibrous);
- woven: graphite, basalt, asbestos and glass fabrics;
- non-woven: quartz, graphite, asbestos, basalt and glass fiber, metallic whiskers;
- skeleton: wrinkled foil, metallic wrinkled net.
Production of PTFE-4 products is based on cold pressing and baking methods.
Depending on average particle size PTFE-4 could be of several grades:
- F-4: particle size 100 – 180 µm;
- F-4 PN-90: particle size 46 – 135 µm;
- F-4 PN-40: particle size 21 – 45 µm;
- F-4 PN-20: particle size 6 – 20 µm.
PTFE-4 has the following number of unique and indisputable advantages, among which it is possible to emphasize:
- very low friction coefficient;
- high resistance to radiation;
- excellent chemical resistance;
- electric insulation opportunities;
- good antifriction parameters;
- low heat conductivity;
- absolute incombustibility and very low smoke generation;
- frost resistance;
- resistance to aggressive environment action;
- absence of ageing and photoageing;
- absolute hydrophobicity;
- non-brittleness.
As disadvantages of PTFE-4 may be classified:
- cold flow;
- high abrasion degree;
- high temperature linear expansion coefficient;
- disposition to recrystallization and residual deformation;
- impossibility to obtain products by casting.
In practice all advantages and disadvantages of PTFE-4 mean the following:
- PTFE-4 bearings while working at high speed will abrade very quickly, but at speed to 0,66 m/min, due to excellent friction coefficient, they will serve much longer than steel bearings;
- Usage of friction parts under load significantly reduces friction force, while PTFE-4 do not require additional application of lubricating materials; PTFE-4 products, due to frost resistance, may be used at negative temperatures. But meanwhile it is not recommended to use them at temperature lower -800С if they bear load over 30 kg/cm3;
- PTFE-4 is indispensable in high-frequency and ultrahigh-frequency technologies, as it has excellent dielectric properties not depending on temperature, current and its frequency; when heating PTFE-4 to +3270С its crystallites began to melt, but the PTFE itself does not transit to viscous flow state.
Distinctive characteristics and positive properties of PTFE-4 permit to use this material in many spheres of industry:
- in machine-building it is used to make various instruments and parts working without lubrication or with minimal lubrication;
- in chemical industry it is used to make vessels for storage and transportation of aggressive liquids;
- in electrical engineering it is used to make electric insulation products; in food industry it is used to produce non-stick and anti-adhesion elements for process equipment;
- in pharmaceutics and medicine PTFE-4 is used for production of prosthesis holders, cardiac valves, vessels for artificial blood circulation apparatuses, etc.
Polymer Company offers high-quality PTFE-4, application of which permits to create products with unique properties.
Call us by telephone +7 (342) 259-07-74 to learn more on products available, prices and delivery terms.
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