CAS NO:162881-26-7 Molecular structural formula: 819 Molecular weight: 418.5 Appearance: Yellow powder Melting point: 127-133 ° C Absorption peaks: 295nm, 370nm (in methanol solution) Solubility: 20 ° C (g/100g solution) Product Overview: Photoinitiator 509 (Photoinitiator 819) is a universal UV initiator used to initiate UV polymerization reactions in unsaturated prepolymers. It can be used for curing thick film systems and is particularly suitable for white systems and glass fiber reinforced polyester/styrene systems. When used in conjunction with light stabilizers, it can also be used for outdoor varnish. Product application: Photoinitiator 509 has been tested and can be used for printing inks and pre impregnation systems on wood, metal, plastic, paper, and fiber optic surfaces. In white paints, colored paints, and inks containing titanium dioxide or other pigments with high coverage, adding a small amount of 509 can make the coating have excellent curing effect and UV yellowing resistance. Due to its excellent absorption performance, 509 can be applied in thick film systems. Photoinitiator 509 can be used in combination with other photoinitiators, such as photoinitiator 504 or photoinitiator 532. The combination of photoinitiator 509 and photoinitiator 532 is particularly suitable for curing polyester/styrene resin systems, such as in glass fiber reinforced materials. Due to its absorption in the long wavelength range, photoinitiator 509 can be used in conjunction with UV absorbers, making it suitable for UV curable coatings that require weather resistance.