Seal manufacturer C. Otto Gehrckens (COG) has presented a product range in the premium segment: the three high-performance materials in the VarioPur series are based on thermoplastic polyurethanes (TPU/AU) and impress with excellent properties and are belonging to the best-case-compounds in the TPU class.
Both the abrasion and the extrusion resistance are up to five times higher than those of the traditional material NBR, which has a Shore A value of 90. Furthermore, the three TPU materials have a high gas tightness and a high level of tolerance to a wide range of gases - from oxygen and nitrogen to all of the synthetic hydrocarbons.
They exhibit no brittleness as a result of exposure to ozone or oxygen. The product's profile is rounded off by low swelling in mineral oil, hydraulic media and lubricating greases, generally good chemical resistance, and superb dynamic behaviour (blow-by behaviour).
In addition to the high-performance universal TPU material COG VarioPur 195, COG introduces two special TPU sealing materials. As well as the complex properties of a high-performance TPU compound, COG VarioPur 295 additionally boasts outstanding low temperature flexibility right down to -50 °C.
COG VarioPur 395 is the top product in this range and sets a new benchmark. Its strength lies in its hydrolysis resistance: a quality that the company believes does not exist in this form in other TPU materials.
This special TPU is extremely stable in aqueous media, including oil-water emulsions (HFA), water-oil emulsions (HFB) and aqueous polyglycol solutions (HFC). It also exhibits outstanding resistance to other critical media, including biologically degradable oils (HEES and HETG), hardly inflammable liquids, triglycerides and synthetic esters of hydraulic oils or water-free media.
The COG VarioPUR TPUs are used in applications in mobile and industrial hydraulics, gas processing technology and gas spring technology, pneumatics, valve technology, the chemical industry and foodstuffs/pharmaceutical processing technologies.