UV-328

UV-328 (CAS 25973-55-1), also marketed as Tinuvin 328, is a benzotriazole-class UV absorber used to protect organic materials from photodegradation caused by UV radiation. It functions by absorbing UV light in the 300–385 nm range.

By dissipating this energy as heat, it prevents color fading, embrittlement, and loss of mechanical performance in finished products. In coatings and industrial paints, it extends the service life of exterior finishes on metal, wood, and plastic substrates.

Automotive OEM and refinish coatings rely on it to maintain gloss retention and prevent yellowing in clear coat systems. Plastics processors incorporate it into polyolefins, PVC, and engineering polymers where long-term outdoor durability is a requirement.

Adhesives, sealants, and elastomers used in construction and glazing applications also use this stabilizer to prevent surface cracking. It is essential for preventing bond failure under prolonged sun exposure in harsh environments.

UV-328 is supplied as a pale yellow to off-white crystalline powder. It is available in technical grade, which is the standard specification for industrial and polymer applications. Packaging typically ranges from 25 kg bags to bulk quantities.

Purity specifications are commonly at 99% minimum by HPLC. This high level of purity ensures consistent performance across various manufacturing processes. The product remains a staple for manufacturers requiring reliable UV protection.