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Sealing materials

Introduction such as strength, ultimate elongation and Thermoplastic
Increasing performance requirements for abrasion resistance . Due to their elastomers
sealing applications due to demanding thermoplastic material behaviour, they
operating conditions raise the importance of soften and eventually melt at high – Polyurethanes
carefully selecting the appropriate sealing temperatures, which limits their upper
materials . These conditions can include high service temperature . ECOPUR DD
speeds, pressures and temperatures, often ECOPUR DD is a thermoplastic polyure thane
in combination with poor lubricating fluids . Elastomers elastomer (TPU) with excellent abrasion
Fluids like HFA and HFB as well as Elastomers are flexible materials with a resistance, low compression set and high
biologically degradable hydraulic fluids generally low modulus that are typically tear strength . It is suitable for hydraulic,
(vegetable oils and synthetic esters) present used for sealing and/or damping pneumatic and selected rotary seals .
additional challenges for the selection of the applications . Due to their chemically cross- Products made from this material can be
right sealing material, as chemical linked structure, they can operate at higher used in mineral oil, in water up to 40 °C .
compatibility of sealing material and temperatures compared to polyurethanes Depending on the seal design and housing,
operating fluid must be ensured . and show a very low compression set . seals made of ECOPUR DD can be used up to
Different types of polymeric materials are Depending on the applied polymer, they can 400 bar (for higher pressures anti-extrusion
available to meet all demands on the seal exhibit excellent chemical resistance . While rings are required) .
assembly in the best possible way . reinforcing fillers improve their mechanical
In this brochure, we feature five different properties, the performance level does not
materials to be used with the SKF SEAL JET reach the level of polyurethanes . Elastomers
DD machine . All of these materials have
been developed by SKF to meet typical SKF Econbr
customer requirements . Additionally, we Thermoplastics
SKF Econbr is an elastomer based on
offer machined seals made of 25 standard Thermoplastic materials show rigid acrylonitrile-butadiene rubber (NBR) and is
materials that are accessible via the SKF behaviour in their operating temperature used for U-cup seals, and rotary seals . The
Machined Seals Centres . There we also have range . As they melt at temperatures above material has good resistance to mineral oils
a vast range of special materials available to their service level, they can be processed and greases and HFA, HFB and HFC
meet very specific application demands like through injection moulding . The selection of pressure fluids .
for food and beverage, oil and gas or the the polymer grade determines the chemical
hydro power industry, just to name some and morphological structure and thus SKF Ecofkm
examples . chemical compatibility as well as mechanical SKF Ecofkm is an elastomer based on fluoro
properties (ductility, stiffness, strength) .
rubber (FKM) and is used for lip seals, wipers
Engineering thermoplastics are generally
Thermoplastic elastomers used for back-up rings, guide rings, and rotary seals . Its outstanding properties
– Polyurethanes bushings, scrapers or other elements of a are high resistance to heat, weathering,
ozone and many other chemicals .
Thermoplastic elastomers are a class of sealing assembly .
copolymers that combine thermoplastic and
elastomeric material properties . For sealing
applications, polyurethanes are the most
important material class of thermoplastic
elastomers . They are processed at SKF as
thermoplastic polyurethanes (TPUs) through
injection moulding and for larger diameters
as cast polyurethanes (CPUs) . Polyurethanes
provide elastomeric material behaviour in
their operating temperature range, which is
required to provide sealing functionality .
They show excellent mechanical properties

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