GB16776-2025
Structural silicone sealants for building
建筑用硅酮结构密封胶
GB 16776-2025 is a current mandatory Chinese national standard for Structural silicone sealants for building. It appears in the Electronics compliance cluster with a product safety focus and has an implementation date of Feb 1, 2026.
Applicability depends on product scope, certification route, competent authority notices and transition rules. Requst for the translation or verify source before using this record in a compliance decision.
Compliance overview
Scope and applicability
This standard applies to structural silicone sealants used in building curtain walls and for the second seal of insulating glass units. It is designed for products categorized by their application, such as curtain wall structural bonding (Category C) and insulating glass structural bonding (Category S). Manufacturers of single-component and dual-component silicone sealants must comply with this standard when supplying to the Chinese construction market.
Technical requirements
GB 16776-2025 specifies comprehensive physical and chemical requirements for structural silicone sealants. It mandates strict criteria for density, sag resistance, and tack-free time to ensure proper application. The standard sets rigorous limits for tensile bond strength across various temperature conditions, including extreme heat and cold. Products must demonstrate exceptional durability and adhesion performance under thermal and UV weathering conditions. Additionally, the standard introduces new parameters such as secant stiffness, shear performance, and strict prohibitions on alkane plasticizers to ensure long-term structural integrity.
Testing methods
The standard outlines specific testing procedures to evaluate the sealant's performance. Key tests include water-ultraviolet light exposure to assess weathering resistance, and thermal aging tests to measure heat weight loss and cracking. Adhesion and shear performance are evaluated using standardized substrates like glass and anodized aluminum. Furthermore, the standard details compatibility testing with structural accessories (Appendix A), actual project substrates (Appendix B), and contact sealants (Appendix C).
FAQs
What products are regulated under GB 16776-2025?
This standard regulates structural silicone sealants used specifically for building curtain wall structural bonding and the second seal of insulating glass units. It classifies products by application into Category C (curtain wall) and Category S (insulating glass).
Are there any updates from the previous version of GB 16776?
The new version merges and replaces the previous GB 16776-2005 and GB 24266-2009. Major updates include the addition of requirements and test methods for density, secant stiffness, shear performance, and alkane plasticizer content, along with updated test methods for water-UV light exposure adhesion.
How does GB 16776-2025 differ from ISO or ASTM standards?
While it shares similar testing principles with international standards like ASTM C1184, GB 16776 is a mandatory Chinese national standard. It includes specific classifications for the Chinese market and unique test parameters, such as strict limits on alkane plasticizers, requiring dedicated compliance verification.
The summary above provides a high-level overview of GB 16776-2025. To ensure complete compliance for your products entering the Chinese market, a precise and professional translation of the full technical specifications is essential. Purchase our high-quality English translation of GB 16776-2025 today to access all detailed parameters, tables, and testing procedures.
Applicability hints
- Type
- Product
- CCS
- Q24
- ICS
- 91.100.50
- Competent department
- Ministry of Industry and Information Technology
- Technical committee
- National Technical Committee on Lightweight and Decorative Building Materials of Standardization Administration of China
Relationships
Replaces:GB 16776-2005, GB 24266-2009