Rubber is a very special material. What makes it particular is its high recovery capacity (elasticity). Thanks to their design, VR seals profit of this capability eminently.
Elastomers consist of a long chain of repeating monomers. Such a chain-like arrangement is called polymer. In the case of elastomers, this rotatability is so distinct that the molecules twist into a so-called polymer branch (rubber elasticity). This endeavour is merely the result of the rotational movement along the chain taking place in completely random directions. The arrangement of the individual atoms of the chain around the centre of the molecule corresponds to a Gaussian distribution.
If a polymer is stretched by a tensile stress, the chains as a result align themselves preferentially in the direction of the load. The elastomer is thus stretched. As soon as the tensile stress terminates, the chains begin again with the random rotary motion, in the course of which they again assume the statistically established Gaussian distribution. The chains “relax” and the elastomer contracts again.
VR Dichtungen offers you a very wide range of elastomers, from NBR for standard seals to the latest high-performance materials, appropriate for FDA / food requirements, too.
Particularly noteworthy in this context are:
*specific variant, please contact us if you are interested
hardness sealing collar
|Colour ||Temperature operating range in °C||General properties ||VR-No.|
|NBR (BFR)||black||-20°C to 100°C||A butadiene – acrylonitrile – copolymer having excellent swelling resistance to solvents based on aliphatic hydrocarbons, regular petrol and mineral oils. Good ageing resistance, low compression set.|
To be used with: petrol, mineral oil, fuel oil, dilute acids and alkalis.
Not to be used with: aromatics, chlorinated hydrocarbons, ketones, esters and ethers, as well as brake fluids based on glycol.
|FKM||green||-12°C to 220°C||Fluor-caoutchouc|
Very good chemical and temperature resistance. Thermal resistance up to 250°C.
To be used with: oils, flame retardant hydraulic fluids, fuels (premium petrol), aromatics, chlorinated hydrocarbons, concentrated acids and alkalis.
Not to be used with: amines and liquid ammonia, ketones, esters, short-chain alcohols and short-chain carboxylic acids.
|blue||-17°C to 220°C||B9|
|FKM /P||grey||-6°C to 220°C||FKM – peroxide|
As (2), but can also be used with hot steam and hot water, as well as with alcohols and SF mineral oils.
Advanced chemical resistance.
|FKM /PTFE(FDA)||white||-17°C to 220°C||As (2) with PTFE deposit for emergency running properties.||8|
|VMQ Peroxyd (FDA)||red||-50°C to 200°C||Outstanding temperature resistance.|
To be used with: dry heat, constant temperature up to 280°C. Resistant in mineral oils up to 150°C. Very resistant to oxygen and ozone. No hardening in hypoid oils. Food resistant.
|HNBR Peroxyd (FDA)||brown||-40°C to 150°C||Very good resistance to hot water and hot steam, oil resistance even at high temperatures.|
To be used with: gasoline – also so-called sour gasoline, high-alloyed oils, cooling water, acids and alkalis.
Not to be used with: Synth, oils and grease, ketones, esters, ethers, aromatics, brake fluids.
|blue||-40°C to 150°C||Very good ageing resistance, high strength.|
To be used with: hot water, hot steam 200°C, ketones, esters, acids, hydraulic and brake fluids based on glycol.
Not to be used with: petrol, mineral oils, aromatics and chlorinated hydrocarbons.
Only use silicone-based greases.
| ||anthracite||As 2 and 5, however, with self-lubricating particles in the basic material.|
For applications without lubrication (water, gasoline, air, food etc.) extremely low friction values and loss moments due to integrated lubrication.
|HNBR-C||-25°C to 150°C||C5|
|FKM-C||-6°C to 220°C||C2|