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).

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[1] ASTM D 395: Standard Test Methods for Rubber Property – Compression Set; ASTM International, 2008

[2] 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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The information provided herein is to the best of our knowledge and it is believed accurate and reliable as of the date compiled. No representation, warranty or guarantee expressed or implied, is made as to the accuracy, reliability or completeness of the information provided herein. It is the user’s responsibility to determine the suitability and completeness of such information for the intended use. We do not accept liability for any loss or damage that may occur from the use of this information. Nothing herein shall be construed as a recommendation for uses which infringe valid patents or as extending a license under valid patents.



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