Primary seal
The thin layer of sealant between the spacer and each pane.
The primary seal is a strip of polyisobutylene (PIB), a soft, sticky sealant, along both sides of the spacer. It is the main barrier that stops moisture getting in and gas getting out.
It is not strong. The secondary seal holds the unit together.
Hover or tap a part to see what it is called.
Related
- Secondary sealThe structural sealant that fills the channel around the edge of the unit.
- SpacerThe bar around the edge of an insulating glass unit that holds the panes apart.
- Gas fillThe gas trapped in the gap between the panes.