Why Does Sealant Change Color?

The Yellowing of Sealant

The main ingredient in mainstream epoxy sealants is epoxy resin. In the sealant formula, the combined A and B component epoxy resin content exceeds 50%. Given that epoxy resin is the primary component, discoloration is inevitable, merely a matter of time. The materials contain chromophoric groups, such as the aromatic ether and benzene ring structures in epoxy resins, and the conjugated double bond structure in unsaturated resins. These structures produce colored substances under UV radiation or oxygen oxidation, manifesting as material yellowing and powdering.

Additional Causes of Sealant Discoloration

1. Uneven material mixing during application, leading to softening and subsequent discoloration.
2. Contamination of tile joints with chemicals or moisture.
3. Low temperatures, high humidity, open windows during application, contact with water before drying, or exposure to strong acids or alkalis.

Are There Non-Yellowing Sealants?

Indeed, some manufacturers have introduced polyaspartic polyurea sealants, a new material different from epoxy systems. Its anti-yellowing performance far exceeds that of epoxy-based sealants. Polyaspartic polyurea has a pure aliphatic structure, free from double bonds and benzene rings prone to yellowing. It fundamentally resolves the issue of sealant yellowing. Moreover, it maintains strong resilience even under humid conditions, unaffected by environments like return-to-south weather or rainy days, as long as the base surface is not overtly wet. Additionally, polyaspartic polyurea itself is a waterproof and anti-corrosion material, retaining these properties when formulated into a sealant, thus offering excellent resistance against everyday chemical corrosion.

Feiyang has been specializing in the production of raw materials for polyaspartic coatings for 30 years and can provide polyaspartic resins, hardeners and coating formulations. Some of our polyaspartic coating formulations: Polyaspartic Coating

Feel free to contact us: marketing@feiyang.com.cn

Our products list:

• Polyaspartic Resin
• Isocyanate Hardener
• Special Chemical

Learn more polyaspartic knowledge: Polyaspartic FAQ