Bulb seals are industrial rubber products that are used to seal and insulate doors, hatches and enclosures.
They fit radiused corners and have separate bulb and retainer sections, each of which can have a different durometer (hardness) and use a different material. The bulb compresses to form a seal when the door, hatch or encloser is closed.
The bulb portion of a bulb trim seal is made of a sponge rubber that provides environmental sealing and resists compression set – the permanent, unrecoverable deformation of a rubber seal after it`s been compressed.
Different compounds are available, but EPDM and TPEs are often used.