Closed cell sponge gaskets are used to prevent the flow of fluids and gases either into or out of an application. While closed cell sponge is an excellent sealing material, offering gap sealing, cushioning, and insulating properties, choosing the right material is key to achieving effective in-service performance.
What is closed cell sponge?
Closed cell silicone sponge contains nitrogen-filled cells or pockets within the material. The nitrogen-filled cells are completely enclosed and non-interconnecting. The resulting sponge is relatively impervious to the transmission of water or moisture through its structure, hence its use in applications where a waterproof seal is desired.
Closed cell silicone sponge is an interesting material. It possesses a high tensile and greater tear resistance, making it a more durable material that silicone foam. The material is highly flexible, meaning it can readily adapt to variety of shapes and contours. It also possesses non-stick properties and has good resistance to ozone and UV light. Natural, synthetic, or reclaimed rubber, together with organic or inorganic additives, can be used as the base material, to manufacture closed cell sponge and create the desired material properties.
Closed cell sponge gaskets
Closed cell sponge gaskets are often fashioned from EPDM, neoprene, or silicone compounds. Blended materials, where multiple compounds are combined together, extend the range of closed cell sponge materials with enhanced performance properties, such as superior resistance to chemical attack and abrasion. Because the range of available closed cell sponge materials is always increasing, buyers should always exercise care in choosing the right material to service their application. Factors that should be considered when selecting a closed cell sponge material for a gasket or sealing application include the following:
- Service temperature range. The material chosen should be capable of withstanding the service temperature range that will be encountered within the application.
- Chemical resistance. Closed cell sponge gaskets used in industrial and automotive applications can be exposed to fluids and lubricants. The material selected should be capable of withstanding any chemical attack resulting from contact with these media.
- UV and moisture resistance. Closed cell sponge gaskets and seals can be exposed to sunlight and weathering, which can result in ageing and degradation of the material.
- Compression set resistance and deflection. Compression set resistance is the ability of a material to return to its original thickness after a compression load, under a specific time and temperature, is released. To ensure the long-term sealing performance of a closed cell sponge gasket, a material with the appropriate compression set for the application should be selected. In some applications, a closed cell sponge gasket may be subjected to constant deflection and flexing of the material. This can cause the walls of the nitrogen cells to break, allowing fluids or gases to pass through the material. For this reason, the ability of a closed cell sponge to resist deflection is an important material selection factor.
- Hardness (durometer) and density. Closed cell sponges are available in various degrees of hardness, which is a function of material density. The degree of hardness desired should be matched to the needs of the application. Higher density materials are better suited for applications where the flow of liquids and gases through the material must be reduced to minimum.
- Flame retardance and safety. Closed cell sponges which retard flames and do not emit noxious fumes when ignited are preferred for applications where the risk of the material burning is real.
- Manufacturability. Depending upon the base compound and additives used in their production, closed cell sponges vary in their manufacturability for conversion into a finished gasket or seal. Manufacturing considerations are therefore an important part of material selection decisions.
CRG supplies closed cell sponge gaskets manufactured from an extensive inventory of materials. Our experienced team can assist in the selection of the optimal material for your application. All gaskets we supply are manufactured on the latest production equipment, ensuring conformity to your specifications and requirements. All stages of production are controlled under our ISO 9001:2015 quality management system. To find out more about the closed cell sponge gaskets we can supply, please contact our sales team at email@example.com.