German chemicals maker WACKER’s new ELASTOSIL LR 3822 is a liquid silicone rubber developed for connector seals and sealing elements in the cooling circuit of EV traction batteries. The cured elastomer continuously releases silicone oil from its surface, and WACKER describes it as the first oil-exuding product that also resists coolant.
That oil bleed leaves a lubricating film on the molded part, and WACKER says the film eases machine assembly. Silicone rubber has a comparatively high coefficient of friction, and dry seals are correspondingly hard to feed, position and press home on an automated line.
Samples stored for 1,000 hours in a glycol-water mixture at 125° C retained most of their mechanical properties, according to the company. Compression set after that exposure measured 44%, which WACKER says leaves sealing elements enough resilience to maintain a consistently high level of sealing performance in the seal groove. The product page rates the grade’s compression set in contact with coolant fluids as extremely low.
Compression set records how much of its original thickness a rubber part recovers after prolonged compression. A seal that takes a permanent set in a hot glycol-water circuit loses the contact pressure that keeps the joint tight. Groove designs rely on the elastomer staying squeezed against both sealing faces for the life of the pack.
The cured rubber can be stretched by 270% without cracks or damage, and it stays elastic at temperatures as low as -45° C. WACKER also describes the material as durable and tear-resistant. Hardness is Shore A 60, which the company says is a specification commonly used in the sealing segment.
The grade is a paste-like two-component compound mixed 1:1. WACKER’s product page puts pot life for the mixed components at a minimum of three days at room temperature. The page also lists reduced volatile content, short curing times and easy pigmentability. The material is supplied in 20 kg pails and 200 kg drum kits.
The product page also names battery coolant connectors, molded automotive seals and radiator-system gaskets among the applications, and the announcement adds weather packs as another possible use.
Source: WACKER
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