Molded Silicone Rubber
LSR’s High Sealing Force Throughout a Product’s Lifetime
The elemental structure of Liquid Silicone Rubber (LSR) enables the material to have a very low compression set; normally in the range of 20 – 40% (22 h @ 350˚C). A low compression set means LSR retains its elastic properties even during prolonged application of compressive stresses (resist creep) such as in sealing or vibration dampening part applications. This resistance to creep allows LSR to maintain its high sealing force during a product’s lifetime. This method allows for producing molded silicone rubber products using liquid silicone rubber with outstanding results.
The compression set of all types of rubbers can be measured according to ASTM D395 or DIN 53517. It is expressed as a percentage of the original deflection at the specified test temperature as well as at a test period of either 22 or 70 hours. Most commonly, it is tested in a static stress condition under constant deflection (Method B of ASTM D395) but the standard also describes dynamic testing. This makes it the perfect candidate for preparing molded silicone rubber products using liquid silicone rubber (LSR).
To learn more about molded silicone rubber and liquid silicone rubber’s outstanding mechanical properties, download our LSR Material and Properties technical paper.
 ASTM D 395: Standard Test Methods for Rubber Property – Compression Set; ASTM International, 2008
 Campo, E.A.: Industrial Polymers; Hanser Gardner Publications, Cincinnati, 2007
At SIMTEC Silicone Parts, a leading company in manufacturing high precision parts and components, we are exclusively focused and specialized in the production of LSR and LSR/Thermoplastic (Two-Shot) components.
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