Glass Glossary

Polyisobutylene (PIB) Sealant


Last Updated: November 23, 2023

Polyisobutylene (PIB) is a synthetic rubber that’s widely utilized in the fenestration industry, particularly in insulating glass units (IGUs). As a sealant, PIB acts as a primary barrier, preventing moisture ingress and retains the gas fill, ensuring the unit’s longevity and performance. Cardinal’s Endur® IG and XL Edge® IG feature PIB as the primary sealant of their dual-seal construction.

Key characteristics and benefits of PIB sealant in IGUs

Superior Moisture Barrier: PIB is renowned for its exceptional resistance to moisture vapor transmission. This ensures that the space between the panes in an IGU remains dry, preventing fogging or condensation inside the unit.

Gas Retention: For IGUs filled with inert gases like argon, PIB’s impermeable nature helps retain the gas, ensuring the thermal performance of the unit remains consistent over time.

Compatibility: PIB sealant is compatible with other sealant materials and glass coatings, ensuring a robust and durable seal.

Flexibility: PIB maintains its flexibility over a wide range of temperatures, allowing it to accommodate the natural expansion and contraction of the IGU due to temperature variations without compromising the seal.

Longevity: Its resilience to aging and degradation ensures that IGUs retain their performance attributes for a longer period, reducing the need for replacements or maintenance.

UV Resistance: PIB does not degrade under UV exposure, ensuring the seal remains intact even in sunlit applications.