How to Select the Secondary Sealant for Insulating Glass Units (IGUs)

The secondary sealant used for insulating glass units (IGUs) must be selected according to the specific application scenario. For point-supported glass curtain wall systems, the secondary sealant for IGUs must be silicone structural sealant. For large-size exposed-frame curtain wall systems, silicone structural sealant for insulating glass is also recommended as the secondary sealant. For windows, doors, and conventional exposed-frame curtain walls, the secondary sealant for IGUs can be silicone insulating glass sealant or polysulfide sealant.

It is well known that polysulfide sealants have relatively poor resistance to UV aging. When polysulfide sealant is used as the secondary sealant in insulating glass, and the bonded area is exposed to long-term sunlight, debonding may occur over time. Therefore, for hidden-frame and semi-hidden-frame curtain wall systems, the secondary sealant for insulating glass must be silicone structural sealant. In addition, the joint dimensions should be calculated in accordance with JGJ 102 – Technical Code for Glass Curtain Wall Engineering, and the minimum bonding width shall not be less than 7 mm.

Users should select appropriate secondary sealant products based on the specific application of the insulating glass. Provided that the sealant quality meets relevant requirements, insulating glass units with a service life that satisfies application needs can be manufactured through proper selection and correct application.

However, improper selection or incorrect use may result in non-conforming insulating glass, even when high-quality sealants are used.

When selecting secondary sealants—especially silicone structural sealants—users should also comprehensively consider:

• The functional requirements of insulating glass units
  
• Compatibility with the primary butyl sealant
  
• Compliance of the silicone sealant's performance with relevant standards
  
  

Our Product Solution

For insulating glass applications, we recommend TNS-723 Two-Part Silicone Insulating Glass Sealant, designed for use as a secondary sealant in double glazing units. It provides strong adhesion to glass and metal, fast and controllable curing for efficient production, and forms a durable, high-modulus, weather-tight elastic seal. TNS-723 is suitable for curtain wall and window IGU systems requiring long-term sealing reliability. If you are interested in our product, please do not hesitate to contact us today!

Contact Person: Tina

Phone No.: 0086-18596167593

WhatsApp: 0086-18596167593

EMAIL：tina@sdsealant.com