COG – C. Otto Gehrckens
VarioPur (photo) is a new product range that includes three high-performance materials based on thermoplastic polyurethanes (TPU/AU). Both abrasion and extrusion resistance are at least five times higher than those of the traditional material, NBR (nitrile butyl rubber). The three TPU materials provide excellent gas tightness and a high level of tolerance to a wide range of gases — from oxygen and nitrogen to all synthetic hydrocarbons. The seals exhibit no brittleness as a result of exposure to ozone or oxygen, and undergo low swelling in mineral oil, hydraulic media and lubricating greases, and have generally good chemical resistance and dynamic behavior. In addition to the high-performance universal TPU material VarioPur 195, the VarioPur 295 delivers outstanding low-temperature flexibility down to –50°C. VarioPur 395 is resistant to hydrolysis, and is extremely stable in aqueous media, including oil-water emulsions, water-oil emulsions and aqueous polyglycol solutions. — COG – C. Otto Gehrckens GmbH & Co. KG, Pinneberg, Germany