“Teflon” is the trade name for “polytetrafluoroethylene” (ptfe), the chemical properties of Teflon.

Description

Polytetrafluoroethylene (PTFE, fluoroplastic 4) is a material with fairly high mechanical properties. At low temperatures it exhibits high strength, toughness and self-lubricating properties; at negative temperatures down to -80°C PTFE (PTFE, F4) remains flexible. Under the influence of external load, polytetrafluoroethylene has the ability to flow coldly (pseudo- or cold flow). Polytetrafluoroethylene (fluoroplastic 4) in comparison with other polymers has the lowest coefficient of friction against steel (about 0.04)

When heated above plus 327°C, the crystallites melt, but the polymer does not transform into a viscous-flow state until the decomposition temperature begins (plus 415°C).

Products made of PTFE (PTFE, F4) can be used at temperatures from minus 269 to plus 260°C and for a short time at temperatures up to plus 300°C. Due to its excellent dielectric properties over a wide range of frequencies and temperatures, PTFE (PTFE, F4) is a unique dielectric. The insulation resistance made from it is very high - exceeds 1016 OhmxSm.

Due to its chemical properties, PTFE polymer has very high resistance to chemically aggressive environments and a list of other equally distinctive properties that are advantageous this material compared to others. Fluoroplastic Teflon is very resistant to almost all acids and alkalis. In particular, this material can withstand exposure to organic and inorganic solvents, petroleum products at wide temperature ranges, from minus 269 degrees to plus 260 degrees. The only exceptions are molten alkali metals, elemental fluorine and chlorine trifluoride. PTFE's unsurpassed chemical resistance characteristics enable it to be used in heavy duty chemical industry for the manufacture of parts required in chemical equipment, various containers, membranes, pipelines, sealing elements, gaskets and pumps.

PTFE is used to produce various packings, thread seals, flange gaskets, mechanical seal parts, impregnations various types to improve the performance characteristics of the coating. Polytetrafluoroethylene can be used in electrical engineering and radio engineering as a material for insulating wires and cables. Sheet Teflon has a very low coefficient of friction; it is almost impossible to wet it with water or any organic liquids, which is perfectly combined with wide temperature characteristics of operation. The low coefficient of specific friction makes PTFE indispensable in mechanical engineering as a gasket material with high antifriction properties.

Specifications

Density, g/cm3: 2.2
Yield strength, MPa: 11.8
Tensile strength, MPa: 14-34
Relative elongation,%: 250-500
Modulus of elasticity (compression/tension), MPa: 410/686
Brinell hardness, MPa: 29-39
Heat capacity, J/(kg C): 1.04
Thermal conductivity, W/(m C): 0.25
Coef. linear expansion, a*10.0000: 8-25
Friction coefficient: 0.04
Operating temperature range, C: -269 to +260

TECAFLON PTFE (Polytetrafluoroethylene)- the technical name of thermoplastic polymers - products of the polymerization of fluorinated olefins. This is the most common fluoropolymer at this time (especially in the CIS). Most Applications received as a material for seals. It is characterized by high chemical resistance, which does not change even when boiled in aqua regia.

Along with phenomenal inertness, fluoroplastic-4 is characterized by low porosity and excellent electrical and mechanical properties. It has a low, almost temperature-independent coefficient of friction (lower than that of ice), is completely hydrophobic, physiologically inert (allowed for contact with food products), in addition, it has exceptional “unstick” properties. Its dielectric properties do not change up to +200°C, and its chemical properties do not change up to +300°C; it is characterized by exceptional resistance to voltage arcs. These properties of the material make products made from it indispensable in the chemical, electrical, mechanical, food, light and medical industries. PTFE is used to make parts, chemical equipment, containers, membranes and diaphragms, valves and pipelines, gaskets and sealing devices, columns and bearings, conveyor belts and much more.

The only polymer resistant to UV radiation in its pure form (uncolored and not UV-stabilized). It is the most resistant of all known plastics to all mineral and organic acids, alkalis, organic solvents, oxidizing agents, gases and other aggressive environments. Resistant to hydrolysis (water absorption less than 0.05%). TECAFLON PTFE is frost-resistant, it does not become brittle even at -269°C, but it mechanical characteristics depend on positive operating temperatures. Wear resistance properties leave much to be desired. PTFE is a highly elastic material with a very low inherent flammability. TECAFLON PTFE has the lowest coefficient of friction of all unfilled polymers.

Fluoroplastics are not flammable or self-extinguish when ignited. Fluoroplastics are poorly soluble or even insoluble in many organic solvents. Fluoroplast-4 is resistant to all acids, petroleum products, and alkalis in the temperature range from -269°C to +260°C, for which it was given the name “plastic platinum”. It is only affected by melts alkali metals, solutions of alkali metals in ammonia, chlorine trifluoride and elemental fluorine at high temperatures.

Mechanical, thermal, electrical properties of PTFE

Parameter	Meaning
Density	2.18g/cm3
Elongation at break	> 50% (DIN EN ISO 527)
Tensile stress	25MPa (DIN EN ISO 527)
Tensile modulus	700 MPa (DIN EN ISO 527)
Impact strength	without damage (DIN EN ISO 179 (Charpy) kW/m2)
Hardness	60 (ISO 2039/2(ball indentation)
Yield strength after 1000 hours under static load	5 MPa
Tensile strength for 1% elongation after 1000 hours	1.58 MPa
Friction coefficient	0.08-0.12 (for steel o=0.05N/mm.sq., v=0.6m/sec)
Wear	21 µ/km (ASTM D 792, DIN EN ISO 1183)
Thermal conductivity	-0.25 W/(K*m), (at 23°С)
Specific heat	1 J/(g*K), (at 23°С)
Linear coefficient of thermal expansion	12 (10-5 1/K) (ASTM D 696, DIN 53 483, IE-250)
Dielectric constant	2.1 (106Hz, ASTM D 150, DIN 7991, ASTM E 831)
Dielectric loss factor	0.0002 (tan)(106Hz, ASTM D 150, DIN 7991, ASTM E 831)
Volume electrical resistance	1016 Ω*cm(ASTM D 257, EC 93, DIN IEC 60093)
Surface resistance	1016 Ω(ASTM D 149, DIN IEC 60093)
Electric strength	48 kV/mm (DIN 53 481, IEC-243, VDE 0303 Teil 2)
Water absorption under normal conditions

Important note! If fluoroplastic-4 “floats”, the closest replacement in a higher class is TECATRON or TECAPEEK. In Russia (due to the wide popularity of the polymer), fluoroplastic-4 is usually used for the manufacture of engineering parts subject to mechanical stress, but operating at temperatures up to +120°C and without exposure to aggressive chemicals. In practice, we often encounter such situations and know numerous solutions and how to save significantly by choosing a more effective and cheaper material.

Applications of TECAFLON PTFE and Fluoropolymers:

PTFE blanks are intended for the manufacture of sealing, electrical insulating, anti-friction, and chemically resistant structural elements by mechanical processing.

In mechanical engineering: in friction units of machine mechanisms and devices as bearings and sliding supports, movable seals for piston rings, cuffs. The use of fluoroplastic in friction units increases the reliability and durability of mechanisms, ensures stable operation in aggressive environments of deep vacuum and at cryogenic temperatures.
In the electronics industry: for insulation of wires, cables, connectors, production of printed circuit boards, slot insulation of electrical machines, as well as in microwave technology. In the medical and pharmaceutical industries: it is used to make prosthetic blood vessels, heart vessels, heart valves, blood and serum storage containers, drug packaging and much more.
IN food industry and household appliances: for the manufacture of linings for rollers for rolling out dough, anti-adhesive and non-stick coatings, for the manufacture of seals for milk pumps and pumps for food liquids, etc.

other types of POM-S, POM-G

PTFE TFM

PTFE TFM is the so-called second generation Teflon, obtained by modification with a small addition of PPVE, which affects the formation of the crystalline phase of the polymer. Significantly shorter molecular chains compared to standard PTFE and a modified crystal structure made it possible to combine certain thermoplastic properties of this modification with the general good mechanical properties of the basic form of PTFE. Modification of PPVE leads to the formation of smaller crystallites, distributed more uniformly and densely, which affects a more uniform structure of the polymer, manifested, in particular, by higher transparency of PTFE TFM compared to the main form. This makes it possible to improve properties of thermoplastics such as conductivity, fluidity and reduced porosity of the plastic.

PTFE TFM is also different:

better mechanical properties, such as: elongation at tension/break, rigidity - especially at high temperatures
significantly less deformation under load and greater ability to return to its original shape after the load is removed
less creep, especially in the range of higher temperatures and/or loads
higher transparency and very smooth surface
welding capability

Application area of PTFE TFM
PTFE TFM is used in the construction of machine and equipment elements that require high survivability of elements, for example, in elements operating with short breaks or service elements over long time ranges. It is used in devices for which high operational reliability and availability are expected, as well as for elements requiring welded connections.

PTFE+ GF

PTFE + GF- is a modification containing the addition of 15 or 25% glass fiber

PTFE + GF different

higher resistance to compression (less susceptibility to creep)
greater dimensional stability
superior resistance to abrasive wear (the addition of GF, however, causes faster wear of the element interacting in pairs).
better thermal conductivity
conditional chemical resistance in contact with alkanals, acids and organic solvents
good dielectric properties

Application area of PTFE + GF
The modification is used in the production of fittings for making cone-shaped valves, the valve support surface, in electrical engineering electrical insulators are made from it, and in sliding pairs it is used as a bearing element.

PTFE+C

PTFE + C - is a modification containing the addition of 25% carbon.

PTFE+C is different

very high hardness and resistance to compressive loads
good sliding properties and resistance to abrasion wear, also in the case of dry friction
good thermal conductivity
low resistance to electrical breakdown and low surface active resistance
less chemical resistance in contact with working fluids with oxidizing properties

PTFE+CF

PTFE + CF- is a modification containing the addition of 25% carbon.

PTFE+CF is different

very little creep
good resistance to abrasive wear, also in aqueous environments
significantly reduced electrical resistance
very good chemical resistance
higher thermal conductivity and lower thermal elongation (also compared to the modification with fiberglass)

Application area of PTFE + CF
The modification is used in the production of machine elements that require removal of electrostatic charge. In the design of chemical devices, it is used to make sliding bearings, housings and valve seats. Other applications include: tight piston guides running without lubrication, various seals, sliding and O-rings subject to abrasive wear during dry operation. The modification is used primarily for the production of sliding bearings and other elements that work with friction.

PTFE + graphite

PTFE + graphite - is a modification containing the addition of 15% graphite.

PTFE + graphite is different

good sliding properties and low coefficient of friction (less than in the case of PTFE + C)
better thermal and electrical conductivity
less chemical resistance in contact with oxidizing agents
relatively high abrasive wear when working in tandem with elements made of metal

Application area PTFE + graphite
The modification is used primarily for the production of slip films that allow the removal of electrostatic charges.

PTFE + bronze

PTFE + bronze - is a modification containing the addition of 60% bronze.

PTFE + bronze is different

good sliding properties and high resistance to abrasive wear - practically the lowest wear among all PTFE modifications
slight creep
good thermal conductivity, allowing to lower the temperature of interacting elements and thereby increase their survivability
limited chemical resistance in contact with acids and water

Application area PTFE + bronze:
The modification is used in the design of machines for the production of bearings and sliding guides, subjected to high mechanical loads, and guide rings in hydraulic cylinders.

Detailed information on non-standard modifications is provided by Plastics Group specialists.

STORAGE
It is best in boxes or on pallets, paying attention to the flatness of the warehouse surface - uneven surfaces can cause irreversible deformation (bending) of stored semi-products.
When storing (for example, slabs) in stacks, attention should be paid to the susceptibility of PTFE to fluidity - storage should be avoided large quantity slabs in one stack ( heavy weight) and other possible threats that may cause deformation of intermediate products.

Properties

Unit change

FPM/FKM
(Vuitton)

PTFE
(Teflon)

P.O.M.
+15%GF
+5%MoS2

dark gray

cream

rigidity

density

tensile strength

modulus of elasticity - (rupture)

70°C/24h 20% Deformation

permanent deformation pressure

100°C/24h 20% Deformation

recoil elasticity

wide tensile strength

abrasion/wear

Minimum temperature

Maximum temperature

NBR, TPU, MVQ,...

Elastomers- these are materials that, through use small force are subject to very strong stretching. Due to their structure, elastomers have a very high degree of ability to return to their original position. This means that the permanent change in shape of these materials is negligible. In principle, elastomers can be divided into two groups: chemical cross-linking elastomers and thermoplastic elastomers. Chemically cross-linked elastomers or rubber materials are high polymers whose macromolecules are cross-linked in large loops by the addition of a vulcanizing agent. Thanks to such chemical cross-linking, they do not melt and disintegrate at high temperatures. Moreover, such cross-linking ensures that the rubber materials are insoluble and, depending on the environment, swell or contract less or more strongly. Thermoplastic elastomers are materials that have characteristic properties elastomers within a high temperature range. However, their cross-linking occurs physically, not chemically. Thanks to this, they melt at high temperatures and can be processed using conventional thermoplastic methods. Thermoplastic elastomers are soluble and have lower swelling properties compared to their chemically cross-linked equivalents.

POM, PA, PTFE + filler, PEEK, ...

Thermoplastics- these are melting high-polymer materials, which in their temperature range of application are much harder and more rigid compared to elastomers. Depending on its chemical composition, the properties of a material can be either brittle and brittle, or viscous and elastic. The morphological composition causes large stretches without returning to the original shape. The shape of the material changes plastically and thus the material is called plastomer. Plastomers are used in sealing technology for solid sealing elements such as support, guide and drive rings.

TPU (green) is a material from the group of thermoplastic polyurethane elastomers. TPU is characterized by particular wear resistance, excellent mechanical properties, extremely low permanent deformation pressure and high tear resistance. In seal technology, TPU is mainly used in the form of sponge rings, wipers, compact seals and chevron seals. The extrusion strength of TPU is far superior to that of rubber plastomers. TPU is suitable for use in special areas such as mineral oils, water with maximum temperature up to 40°C and in biodegradable hydraulic fluids at 60°C. Without back-up rings, TPU seals apply up to a maximum pressure of 400 bar, depending on the profile geometry.

TPU (red) is a hydrolysis-resistant thermoplastic polyurethane elastomer. It combines approximately the same mechanical properties of TPU and high stability, unusual for polyurethanes, in hydrolysis environments (with water temperatures up to 90 ° C) and mineral oils. These properties allow application in water hydraulics, tunnel construction, mining and press manufacturing. The gas permeability of TPU (red) is much lower compared to TPU (green), so it is especially used in high pressure gases.

CPU (red) is a molded elastomer produced using a special injection molding process from the same raw materials as TPU (red). It has the same chemical and mechanical properties as TPU (green), but is used for semi-finished products in sizes from 550 mm to 2000 mm and special sizes with extremely thick walls.

TPU (blue)- This is a modified TPU for use at low temperatures. TPU (blue), unlike the TPU (green) material, goes into a state of fluidity at a lower temperature (-42°C) and has higher elasticity and residual deformation (45%). Suitable for use in cold weather climatic conditions(- 50°C).

TPU (gray)- This is a completely new thermoplastic polyurethane elastomer, with additives of composite materials that provide constant lubrication. This ensures a constant reduction in friction, increased sliding speed and reduced wear. Used for operation in conditions of poor lubrication (dry running), or lack of oil lubrication: water hydraulics and pneumatics (without oil).

NBR (black) is an elastomer based on cross-linked sulfur acrylic-nitrile-butadiene rubber. It has high hardness and, for rubber elastomers, high abrasion resistance. At high temperatures, especially in an oxygen environment (air 80°C), aging accelerates, the material becomes hard and brittle. When air access is blocked, the aging process slows down significantly. Due to its unsaturated structure, NBR has low resistance to ozone, weathering and aging. Swelling in mineral oils is negligible, but is within strong addiction on the composition of the oil. Gas permeability is relatively high, as a result of which there is a danger of explosive decompression, in which parts of the material rupture. It is used in areas where, in addition to high resistance to fuel and mineral oils, high elasticity and permanent deformation are also required (cylinder seals at low pressures).

H-NBR (black)- this is hydrogenated acrylic-nitrile-butadiene rubber and has, compared to NBR, better mechanical properties, high resistance in chemical environments such as propane, butane, mineral oils and fats, with a high percentage of additives, in dissolved acids and alkalis at a wider temperature range (-25°C to +150°C). Also more resistant to ozone, weather and aging. At the same time, it remains highly elastic. Used in engine and gearbox seals, crude oil and natural gas production, etc.

FPM, FKM (brown)- elastomer based on fluoro-rubber cross-linked with bisphenol (Viton - trademark Du Pont). Designed for groove rings, wipers, sponge rings, chevron seals, etc. It is highly resistant to temperatures, chemicals, extreme weather conditions and ozone. Temperature range: from -20°C to + 200°C (short-term up to 230°C). Used in hydraulic systems with highly flammable liquids of the HFD group (phosphorus based). Low resistance to ammonia and ammine environments, polar solvents (acetone, methylethylketone, dioxane), and glycol-based brake fluids.

EPDM (black)- an elastomer based on peroxide-crosslinked ethylene-propylene-diene rubber. It has good mechanical properties and a wide temperature range of application: from - 50°C to + 150°C, hot steam up to 180°C. Due to its non-polarity, it is not stable in hydraulic fluids based on mineral oils and carbohydrates. Used in conditions of hot water, steam, alkalis and polar solvents (in washing and cleaning equipment). When used in brake fluids based on glucol, compliance with regional regulations is required. Resistant to weather, ozone and aging.

MVQ (brown) is an elastomer based on methyl vinyl silicone rubber. Free of soot and suitable for electrical insulation. Temperature range from - 60°С to +200°С. Used for O-rings, flat and special seals, in the food and chemical industries. Due to its low mechanical values (compared to other rubber materials) it is used primarily in static seals. Swelling in mineral oils is negligible, but depends on the composition of the oil.

PTFE (white) is a crystalline thermoplastic based on the chemical basis of polytetrafluoroethylene (Teflon). An exceptionally wide temperature range of application (-200°C to +200°C), the lowest coefficient of friction (m=0.1) among all plastic materials and a very high degree of resistance to almost all environments. PTFE has a non-stick surface, does not absorb moisture and has very good electrical properties. It is important to take into account the time-dependent plastic deformation of PTFE even under light load (cold flow). Resistant to almost all chemicals except elemental fluorine, chlorotrifluoride and molten alkali metals. Therefore, it has the widest range of applications in technology.

PTFE + filler (gray)- differs from PTFE in its own way chemical composition added fillers (15% glass fiber and 5% molybdenum disulfide), which reduce plastic deformation under load (reduced cold flow, increased extrusion resistance). It is used in sealing elements for low friction with high loads, for sliding and supporting elements, where pure Teflon cannot be used. Due to the presence of fillers, it cannot be used in the food industry.

POM (black)- technical thermoplastic based on polyacetal (polyoxymethylene). It has a high ability to retain shape, high surface resistance, elasticity and low moisture absorption. The tendency to cold flow at temperatures below 80°C is insignificant. POM is an excellent material under sliding and wear conditions and has excellent mechanical properties. POM is used where high hardness and low friction are required, that is, for guides and support elements (at T = 100°C). Not stable enough in acids and alkalis.

PA (black)- thermoplastic based on cast polyamide. Used instead of POM for diameters greater than 250 mm. High ability to retain shape, elasticity and rigidity, but prone to moisture absorption (loss of rigidity and change in volume). Use in watery environments is not recommended. Well suited for sliding operation (support, guide rings).

PEEK (cream)- thermoplastic based on polyaryletherketone from a number of highly temperature-resistant artificial materials. It is used mainly in those areas where, due to high temperatures (up to +260°C), high chemical and mechanical requirements, the use of conventional technical plastic materials is impossible. Universal stability in many chemical environments (with the exception of sulfuric acid, saltpeter) determines the use of PEEK in the oil and gas and chemical industries. Widely used in electrical engineering and electronics due to its good electrical properties in combination with mechanical properties.

15..27 N/mm² Thermal properties T. dec. 415 °C Ud. heat capacity 1040 J/(kg K) Thermal conductivity 0.25 W/(m K) Coeff. warm extensions (8..25)∙10 -5 Classification Reg. CAS number 9002-84-0 Reg. EINECS number 618-337-2 ChEBI Data are given for standard conditions (25 °C, 100 kPa) unless otherwise stated.

Polytetrafluoroethylene, teflon or fluoroplast -4(-C 2 F 4 -) n is a polymer of tetrafluoroethylene (PTFE), a plastic that has rare physical and chemical properties and is widely used in technology and in everyday life.

The word "Teflon" is a registered trademark of the DuPont Corporation. The nonproprietary name for the substance is “polytetrafluoroethylene” or “fluoropolymer.” In the USSR and Russia, the traditional technical name for this material is fluoroplastic.

Polytetrafluoroethylene was discovered in April 1938 by 27-year-old chemist Roy Plunkett of Kinetic Chemicals, who accidentally discovered that tetrafluoroethylene gas he pumped into pressurized cylinders spontaneously polymerized into a white paraffin-like powder. In 1941, Kinetic Chemicals was granted a patent for Teflon, and in 1949 it became a division of the American company DuPont.

Properties

Physical

Teflon is a white, transparent substance in a thin layer, resembling paraffin or polyethylene in appearance. Density according to GOST 10007-80 from 2.18 to 2.21 g/cm3. It has high heat and frost resistance, remains flexible and elastic at temperatures from -70 to +270 °C, an excellent insulating material. Teflon has very low surface tension and adhesion and is not wetted by water, fats, or most organic solvents.

Fluoroplastic is a soft and flowing material that has limited use in loaded structures. Has very low adhesion (stickiness).

DuPont specifies the melting point according to ASTM D3418 for different types Teflon from 260 °C to 327 °C.

Chemical

In terms of its chemical resistance, it surpasses all known synthetic materials and noble metals. It is not destroyed under the influence of alkalis, acids and even a mixture of nitric and hydrochloric acids. Destroyed by molten alkali metals, fluorine and chlorine trifluoride.

Production

The production of polytetrafluoroethylene includes three stages: in the first stage, chlorodifluoromethane is obtained by replacing chlorine atoms with fluorine in the presence of antimony compounds (Swarts reaction) between trichloromethane (chloroform) and anhydrous hydrogen fluoride; in the second stage, tetrafluoroethylene is obtained by pyrolysis of chlorodifluoromethane; at the third stage, the polymerization of tetrafluoroethylene is carried out.

Products from f-4 are produced by cold pressing followed by baking at a temperature of 365±5 °C. The pressing process proceeds from an aqueous PTFE emulsion in the presence of a surfactant (for example, perfluorooctane or perfluorooctanesulfonic acids), which stabilizes the emulsion and makes it possible to produce water-dispersed polytetrafluoroethylene.

The main producer of fluoroplastic in Russia is the Kirovo-Chepetsk Chemical Plant named after Konstantinov, Kirovo-Chepetsk, Kirov Region.

Application

Industry and technology

Due to its chemical inertness, hydrophobicity and fluidity, the material is widely used for sealing threaded and flange connections (FUM tape).

Lubrication

Fluoroplastic (Teflon) is an excellent anti-friction material with a sliding friction coefficient that is the lowest of any known structural material available (even less than that of melting ice). Due to their softness and fluidity, solid fluoroplastic plain bearings are rarely used. In highly loaded units, metal fluoroplastic liner bearings and metal fluoroplastic support belts are used. Such a sliding element can withstand tens of kilograms per square millimeter and consists of a metal base on which a fluoroplastic coating is applied.

Electronics

Teflon is widely used in high-frequency technology, since, unlike polyethylene or polypropylene with similar properties, it has a coefficient that varies very little with temperature dielectric constant, high breakdown voltage, as well as extremely low dielectric losses. These properties, along with heat resistance, make it wide application as insulation of wires, especially high-voltage ones, all kinds of electrical parts, in the manufacture of high-quality capacitors, printed circuit boards.

In electronic engineering special purpose Wiring with fluoroplastic insulation, resistant to aggressive environments and high temperatures, is widely used - wires of the MGTF, MS and a number of others brands. It is impossible to melt a wire in Teflon insulation with a soldering iron. The disadvantage of fluoroplastic is its high cold fluidity: if you hold a wire in fluoroplastic insulation under mechanical load (for example, put a furniture leg on it), the wire may become exposed after some time.

Medicine

Due to its biological compatibility with the human body, polytetrafluoroethylene is successfully used for the manufacture of implants for cardiovascular and general surgery, dentistry, and ophthalmology. Teflon is considered the most suitable material for the production of artificial blood vessels and cardiac stimulators. In 2011, it was first used for plastic surgery of damaged nasal septum and walls of the paranasal sinuses instead of titanium meshes. After 12–15 months, the implant completely dissolves and is replaced by the patient’s own tissue.

Teflon is also used in the production of other household appliances. Teflon coating in the form of a thin film is applied to razor blades, which significantly extends their service life and makes shaving easier.

Caring for Teflon-coated cookware

Teflon coating is not very durable, so when cooking in such dishes, you should use only soft - wooden, plastic or plastic-coated accessories (spatulas, ladles, etc.). Teflon coated utensils should be washed in warm water with a soft sponge, with the addition of liquid detergent, without using abrasive sponges or cleaning pastes. Avoid overheating and frying over high heat.

Cloth

In the production of modern high-tech clothing, membrane materials based on expanded polytetrafluoroethylene are used.

By physically deforming Teflon, a thin porous film is obtained, which is applied to fabrics and used in sewing clothes. Membrane materials, depending on the manufacturing features, can have both windproof and waterproofing properties, while the normalized pore size of the polytetrafluoroethylene membrane allows the material to effectively transmit evaporation from the human body.

There is a fabric-based polytetrafluoroethylene membrane material that allows air to pass through but does not allow wind to pass through.

Gore-Tex is a waterproof, breathable membrane.

Other products

Products in the production of which Teflon is used:

heating lamps;
portable heating devices;
iron plates;
ironing board coverings;
stove burners;
baking sheets;
electric grills;
devices for making popcorn;
coffee pots;
rolling pins (with anti-stick coating);
bread baking machines;
trays for skewer or grill;
ice cream molds;
toilets with Teflon coating;

boilers;
corkscrews;
surfaces of kitchen stoves;
kitchen utensils;
pots and pans for frying;
woks (Chinese pans for frying vegetables and meat);
baking dishes;
hot sandwich press;
waffle irons;
optical cryostats;
razor blades;
internal coatings of tank barrels; [ ]
electric rocket engines [ ] .
paint and varnish materials [ ]
seals of articulated mechanisms (hinges)

The dangers of polytetrafluoroethylene

The possible negative impact of polytetrafluoroethylene on human health has been the subject of controversial opinions for many years. The polymer itself is very stable and inert under normal conditions. Polytetrafluoroethylene does not react with food, water and household chemicals.

Polytetrafluoroethylene is harmless when ingested. The World Health Organization has asked the International Cancer Control Organization to conduct an experiment on rats. Experience has shown that when consumed in food up to 25% of polytetrafluoroethylene it has no effect. This study was conducted in the 1960s and again in the 1980s on a general population of rats that consumed 25% of their total food intake of PTFE each day.

Research by French experts, who published the results of a laboratory study of 13 samples of frying pans in the journal 60 Millions de Consomateurs, confirms the safety of the non-stick coating. French magazine reports that as a result of tests, the frying pans were completely safe. All samples successfully passed the test after rubbing the surfaces with an abrasive material a thousand times over two cycles.

Fluoroplastic is potentially biologically hazardous in two cases: during production and overheating of the finished polymer. Polymer production uses toxic and carcinogenic substances that can enter the environment both through leaks and in the form of industrial contamination of the finished product. The thermal decomposition products of fluoroplastic are toxic.

Industrial pollution

The main source of biological risks in the production of fluoropolymers is considered to be perfluorooctane acid (PFOA). This compound has been used in the USA since the 50s of the 20th century. The first information about the impact on health was obtained at the 3M and DuPont factories in the 60s. In the 80s, scientific groups joined the study of biological effects. In the late 1990s, US regulatory authorities drew attention to the problem, which resulted in the recognition of the danger of the substance and the regulation of maximum concentrations. Processes throughout the United States have been modified to eliminate PFOA completely. Large-scale campaigns have been launched to monitor PFOA concentrations and clarify its impact on human health.

DuPont has received hundreds of millions of dollars in lawsuits from company workers and surrounding communities over health claims and cover-ups of manufacturing hazards. In 2006, DuPont, by then the only manufacturer of PFOA in the United States, agreed to remove the remaining reagent from its facilities by 2015. According to official company information, since January 2012, DuPont has not used PFOA in the production of cookware and bakeware.

It is known that perfluorooctanoic acid decomposes at a temperature of 190 ºС, while the technological process of sintering the base of a non-stick frying pan occurs at a temperature of 420 ºС. Thus it is assumed that, according to technological process, the presence of PFOA in the finished pan is unlikely. However, a 2005 study found PFOA levels in PTFE coatings on new cookware ranging from 4 to 75 µg/kg (at levels in cling film about 1800 mcg/kg and in popcorn packaging material up to 290 mcg/kg).

Independent European studies have shown that non-stick coatings do not contain PFOA in quantities exceeding acceptable safety limits. Chinese Academy of Quality, Inspection and Quarantine (GAQSIQ), Danish technological institute confirm that no exposure to PFOA used in cookware has been detected. .

Not in Russia regulatory documents, limiting industrial contamination of fluoroplastic, which can negatively affect the quality of products containing fluoroplastic.

Thermal decomposition of polytetrafluoroethylene

The rate of Teflon pyrolysis depends on the degree of polymerization. Signs of decomposition are detected at a temperature of 200 °C. The process is relatively slow up to 420 °C. At temperatures from 500 °C to 550 °C, weight loss reaches 5-10% per hour in inert environments, sharply accelerating in the presence of atmospheric oxygen. At temperatures between 300 and 360 °C, the decomposition products are predominantly hexafluoroethane and octafluorocyclobutane. Above 380 °C, perfluoroisobutylene and other pyrolysis products appear.

Among the products of thermal decomposition of polytetrafluoroethylene, perfluoroisobutylene is considered the most dangerous - an extremely poisonous gas, which is approximately 10 times more poisonous than phosgene.

Thermal decomposition products cause a picture of poisoning reminiscent of foundry fever. Possibly, polytetrafluoroethylene aerosol is also poisonous and has a pyrogenic effect, especially when freshly obtained, on which destruction products are sorbed. When inhaling cold polytetrafluoroethylene dust, after 2-5 hours all workers experienced symptoms called “Teflon fever.” Typical Teflon fever has been observed when working with polytetrafluoroethylene heated to >350°C. When examining 130 people and the presence of polytetrafluoroethylene aerosol in the air at a concentration of 0.2-5.5 mg/m3, it was revealed that the majority of workers had repeated attacks of fever. The same individuals had fluoride in their urine (0.098-2.19 mg/l). Fluoride excretion turned out to be significantly higher with longer duration and repeated attacks.

Since the massive release of toxic substances by Teflon begins at temperatures above 450 °C, cookware with non-stick coatings is considered safe, since such temperatures cannot be reached during normal operation. It should be borne in mind that manufacturers consider only heating with water or oil in a frying pan to be the norm. Water prevents the Teflon from overheating. Edible oils decompose at temperatures up to 200 °C with the release of smoke, which facilitates the identification of overheating. Heating dry utensils on a stove is considered abnormal and in this case the pyrolysis temperatures of Teflon are easily achievable. To simplify operation, the cookware can be equipped with built-in visual temperature indicators.

Soldering wires with fluoroplastic insulation requires exhaust ventilation.

Danger of Teflon decomposition products for birds

The special structure of the respiratory system of birds makes them hypersensitive to toxic substances contained in environment. It has been established that even minimum quantity perfluorooctanoic acid, entering the bird's body with inhaled air, affects its respiratory system, leading to death after some time (from several minutes to tens of hours). Small birds are more sensitive to toxic substances; a few seconds of inhaling Teflon fumes are enough for them, and death occurs within the next 24 hours.

At first, when news about the deadly dangers of Teflon for birds first appeared, it was generally accepted that deadly fumes were released only at very high temperatures. To date, the death of 52% of birds that have been breathing fumes from Teflon surfaces of lighting lamps heated to 202 °C for 3 days has been reliably recorded. Other sources suggest that as little as 163°C (325°F) or even 140-149°C (285-300°F) is sufficient, but these data require further verification.

There is a lot of information about the death of poultry (for example, parrots) from the fumes of Teflon pans left unattended and overheated above a safe temperature.

Notes

Slippery type: Teflon - Popular Mechanics magazine
Roy J. Plunkett - Chemical Heritage Foundation
Accidental Invention of Teflon
What lab accident created Teflon
Fluoropolymer Comparison - Typical Properties
Utkin V.V. Factory near Mesopotamia. Kirovo-Chepetsk chemical plant. - with color tabs. - Kirov: OJSC "House of Printing - Vyatka", 2006. - T. 3. - 240 p. - 1000 copies. - ISBN 5-85271-250-7.
Utkin V.V. 1 // Factory near Mesopotamia. Kirovo-Chepetsk Chemical Plant named after B.P. Konstantinov. - with color tabs. - Kirov: OJSC "House of Printing - Vyatka", 2007. - T. 4. - 144 p. - 1000 copies. -