Sealing technology manual for the process industry

PEEK – Polyetheretherketone PEEK (Polyether-ether-ketone) has a similar chemical resis- tance to PTFE, but with improved mechanical properties. This material is renowned for its almost universal chemical resistance and high temperature resistance (+260 °C/+500 °F continuous operating temperature) and is therefore growing in popularity. Suitable areas of application While only of limited use in seals due to its lack of elastici- ty, PEEK is increasingly finding application opportunities as a backup ring for O-rings under high pressure, or in V-Seal set packings as backup rings or compression rings. Unfilled PEEK is FDA-compliant, but there are also options here to modify the mechanical properties by means of fillers such as glass fiber and carbon fiber or PTFE. In contrast to PTFE, PEEK can also be processed by injection molding. Products • Backup rings for O-rings • Backup rings in V-Seal set packings • Compression rings in V-Seal set packings PU – Polyurethane Polyurethane (PU or PUR) is a plastic that can be processed with almost all methods of plastics technology. Polyure- thanes are linear or cross-linked high polymers that are formed by the reaction of di- or polyisocyanates and hy- droxyl carriers such as polyols, chain extenders and cross-linkers and potentially other components. Common to all of them is the urethane bond created by this reaction, which gives the name to this material group. Thanks to the highly polar urethane group common to all polyurethanes, this plastic is characterized particularly by: • High tensile strengths (far in excess of 60 MPa) • High elongations at break (in some cases more than 1,000%) • Elasticity • Abrasion resistance • Oil resistance • Ozone resistance Suitable areas of application Using special raw materials, it is possible to achieve good hydrolysis, acid and alkali resistances as well. Polyurethanes cannot be used in contact with amines, glycols and chlorin- ated solvents. Since the urethane group is non-toxic and bi- ologically very compatible, polyurethanes are especially well-suited for drinking water and food applications in com- pliance with KTW and FDA standards. A high-quality sub- group of the polyurethanes are the thermoplastic polyure- thanes. These often expensive granulates can be processed into extremely high-quality components, e.g. by means of injection molding or extrusion processes, with reasonable processing costs. Products • U-packings • Wipers APPENDIX PRODUCT PORTFOLIO MATERIALS RESISTANCE & PURITY ENGINEERING PLASTICS ELASTOMERIC MATERIALS TECHNICAL FUNDAMENTALS INTRODUCTION 53

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