Viton® FKM FPM Rubber – Fluorine Rubber
Viton® rubber is a specific product of the fluorine rubber monomer copolymerization process. It is also marketed under other names such as fluoro rubber, FKM and FPM. The name of this material is proprietary to DuPont. Viton is a very high-quality product, distinguished by its remarkable resistance. It has high mechanical strength and resistance to damage, temperature extremes or aggressive substances.
It is an uncompromising solution in the range of rubber products – this fluoroelastomer has the highest possible parameters, which will prove resistance in the most difficult and demanding working conditions.
What does FKM and FPM stand for?
Viton is a fluorine-based rubber formed in the chain of copolymerization reactions of monomers in which the molecules contain fluorine. These are exactly the fluorides of vinylidiene and hexafluoropropylene, interchangeable with the fluorides of vinylidene and trichlorethylene. The features for which Viton received special recognition in the market are particularly durable behavior against extreme temperatures and non-flammability. Fluorine vulcanizates are also characterized by partial gas permeability. Viton may slightly lose weight when in a vacuum. Most rubber compounds have similar mechanical properties to Viton.
Viton vulcanizates are marked with the abbreviation FPM. On the other hand, fluorine or fluorine-based rubbers will be abbreviated as FKM.
At first glance, it is possible to distinguish what materials are hidden in the fluoro rubber seals viewed by the buyer. Viton O-rings are usually black, while FKM FPM O-rings are green or black with a green mark at the outer edge. You can also find them in brown and any other color on request.
The history of Viton®
The history of Viton begins in the 19th century. In 1802, Éleuthère Irénée du Pont de Nemours founded a company that initially produced black powder. It is hard to believe that today it is a public company listed on the New York Stock Exchange. Today, it is also one of the largest chemical companies in the world. An interesting fact is that its founder was the son of Stanisław Poniatowski, the secretary of the king of Poland. The city in which the company was born was Brandywine Creek, in the USA. Throughout the nineteenth century, DuPont invested in the chemical market, but it was in the twentieth century that it was the time of real glory for the company. It was then that scientists working on behalf of DuPont invented very durable materials, including:
and the aforementioned Viton. DuPont was responsible for the revolution in polymer materials.
In 2012, Viton appeared on the market and was officially presented at the DKT (Deutschen Kautschuk-Tagung) conference in Nuremberg.
Viton® rubber application
This rubber, extremely durable material, among many vulcanization materials available on the market, is distinguished by properties that are very valuable for the industry:
- resistance to vacuum,
- resistance to UV radiation,
- durability in the ozone environment,
- refraining from exposure to mineral oils and greases, including those containing additives enriching their mixtures,
- resistance to inorganic acids such as sulfuric, hydrochloric, phosphoric and nitric acids,
- excellent durability against slow-burning hydraulic fluids which contain phosphoroesters and chlorinated hydrocarbons (HSC).
It is these characteristics of the material that make it highly valued in demanding industries. It is used by coal and even nuclear power plants. Companies in the gas, oil and petrochemical industries also benefit from the indestructible structures of this rubber. It is worth emphasizing that the oil industry is also based on production processes in which Viton rubber is the rubber protection. Also, the method of transporting crude oil is carried out using this material. In fact, the unique properties of rubber that have been recognized for the transportation of crude oil are more widely used in the transportation of other types of chemicals, handling mechanisms and desulfurization systems. Viton also meets in the aerospace and food industries.
Due to its low gas permeability, this synthetic rubber also appears in seals in vacuum applications.
Viton is a reliable material. It protects various surfaces against aggressive chemicals in unusual environments. The conditions that qualify as atypical are, first of all, the high temperatures that are generated during the operation of engines or turbines, and the low temperatures at which flexibility is required. The operating range of Viton in the temperature forks is -25 to 210 degrees Celsius. However, it has been observed that at the temperature of 230 degrees Celsius, short-term seals also do not deteriorate. This rubber is dimensionally stable and has self-lubricating properties, which is used in the automotive industry – fuel systems, engines. The shape-retaining property has also found application in various types of pumps and valves in pneumatic and hydraulic systems.
FKM FPM rubber – Operating temperature range for FKM FPM rubber
Rubber compounds commonly called fluorine (due to the fact that they contain Fluorine which increases resistance and gives the properties of rubber to work at high temperatures) have a specific temperature range.
The range is:-25 ° C to + 210 ° C. Depending on the use of the mixture, even up to +230 and 250 ° Celsius.
The indicated range makes the mixture dedicated to high temperatures, such as high-temperature O-rings used in engines and high-pressure injectors.
Viton® a material for many generations!
Synthetic Viton rubber, also known as a fluoropolymer elastomer, is commonly used in o-rings. Viton fluoroelastomers are classified according to the markings:
- FKM ASTM D1418
- ISO 1629.
Their class also includes:
- tetrafluoroethylene terpolymers (TFE),
- vinylidene fluorides (VDF or VF2)
- hexafluoropropylene (HFP) and its copolymers
- perfluoromethylvinylether (PMVE).
Rubber materials, in order to be classified under Viton, must contain a fluorine content of 66 to 70%. Viton most often comes in green or brown color. However, this is not the most accurate or the best way to recognize it. It is better to subject it to density tests which is more than 1800 kg / m3. It is much higher than that of other rubbers, the density of which oscillates around 1.010 – 1.520 kg / 3.
Viton® can be divided into 4 families:
- Viton A® – VF2 / HFP dipolymers – universal sealing, resistant to fuels and mineral greases, fluorine content is about 66%,
- Viton B® – VF2 / HFP / TFE terpolymers – used in chemical industry plants and as power seals, fluorine content is 68%,
- Viton F® – VF2 / HFP / TFE terpolymers – coping with oxidized car fuels, concentrated aqueous inorganic acids, water, water vapor, fluorine content is 70%,
- special types including: GLT, GBLT, GFLT and Viton Extreme, which applies to TFE / propylene and ethylene / TFE / PMVE copolymer materials used in the automotive industry, in oil extraction and in specialty seals.
The resistance to aggression of Viton chemicals depends on the nature of the primary polymer and the ingredients used in the processing of the end products. O-rings can be an example of this. Of course, material performance may vary as there are many plants that manufacture Viton polymers.
When working with synthetic rubber with the addition of fluorine, be especially careful in the event of very high temperatures or direct fire. Fluoroelastomers can decompose and release poisonous hydrogen fluoride. Remnants and waste of materials in contact with Viton under such conditions should be disposed of with the use of specially prepared protective equipment.
Viton® – POWER Rubber seals
Viton seals, i.e. fluorine rubber, are made of an extremely durable material – Viton. It is used to create O-rings or flat sealing mats, or a gasket shape chosen by the customer. There are sealing plates, flat gaskets, O-rings, profiles, cords and simmerings available on the market. With the help of a laser plotter, forms of Viton can be cut and trimmed.
Viton O-rings better than NBR O-rings
Commonly used rubber O-rings are seals made of a nitrile mixture, i.e. NBR. This material exhibits oil resistance properties, but only to a basic extent. Additionally, the working temperature is up to +100 ° C – POWER Rubber recommends use up to +90 ° C.
But what when we need greater chemical resistance and higher temperature resistance for O-rings?
This is where FKM FPM O-rings come in handy and are often known as high-temperature O-rings. They enable work up to +220 ° C.
They show chemical resistance to mineral and even synthetic oils, lubricants, constant contact with fuel, oil and derivatives. They are often called oil o-rings. Seals made of this material also show dedicated resistance, e.g. in contact with food – FDA Viton®
FKM FPM and Viton® rubber sheets
Rubber oil plates are plates made of fluorine mixtures. Their main advantage is very high resistance to constant contact with lubricants, oils and fuels: gasoline and crude oil.
Oil plates are available in the following thicknesses:
- 1 mm
- 1,5 mm
- 2 mm
- 3 mm
- 4 mm
- 5 mm
- 6 mm
- 8 mm
- 10 mm
- 12 mm
- 15 mm
Technical data of FKM FPM boards
Hardness: The most common hardness of the boards is 75 ShA (Shore A scale). However, the production possibilities allow obtaining boards with hardness of 70 ShA.
Recommended temperature range: from – 20 ° C to + 220 ° C, and in the high-temperature version even up to + 275 ° C
Tensile strength: 200%
Chemical resistance: high resistance to ozone and permanent contact with mineral and vegetable oils, HFD hydraulic fluids. They meet the ASTM-1 and IRM 902 and 903 standards
If broadly understood rubber products for contact with foodstuffs are needed, the FFKM mixture is also appropriate for this type of application. However, it is worth remembering that for professional use rubber articles should be FDA certified.
FDA certification (source: Food and drug administration https://www.fda.gov/), i.e. the American equivalent of the Food and Drug Administration. It confirms the admissibility of seals for contact with food products – food, and even with running water.
We meet the expectations of our clients. We design and manufacture Viton technical seals on an individual order.
Viton® is the official registered name of DuPont® rubber compound at www.dupont.com