There are several reasons for the yellowing of FRP products:
1. During the synthesis process of unsaturated resin esterification, due to the thermal aging yellowing caused by high temperature, the temperature of the glass steel sheet is between -30°C~+130°C. If the temperature exceeds this range, the resin will easily turn yellow, which will affect the appearance of the resin product. ;
2. The yellowing of the resin caused by exposure to ultraviolet light may be due to the thermal oxygen degradation of the compound of the resin itself at high temperature, which is prone to electronic transitions, making the resin yellow;
3. In the process of resin production, the raw materials are exposed to oxygen due to poor sealing of the device and other reasons. The general unsaturated polyester molecular chain not only contains ester groups, hydroxyl groups, and carboxyl groups, but also contains double bonds and aromatic rings. A trace amount of oxygen can make it Occurrence of thermo-oxidative degradation, the most obvious manifestation is that the color of the resin turns yellow.
4. The influence of additives such as antioxidants, polymerization inhibitors, curing agents, etc., amine antioxidants are easily converted into nitrogen oxide free radicals to color the product. Commonly used polymerization inhibitors, such as hydroquinone, are When present, it is oxidized to quinones, which themselves have color, thus affecting the color of the resin.
To sum up, ultraviolet rays and thermal oxidation are the main factors affecting the yellowing of FRP sheets. If you have any questions about FRP panels or you want to buy FRP panels, please contact us! Runfeng has been focusing on the production of FRP panels for more than 10 years, providing you with high-quality products and satisfactory prices.