Used as a stabilizer in polymers, particularly in polyolefins such as polyethylene and polypropylene. It prevents degradation caused by heat and UV exposure during processing and in end-use applications. Offers excellent resistance to hydrolysis and maintains polymer color stability. Commonly employed in wire and cable insulation, automotive components, and packaging films where long-term thermal and oxidative stability are required. Also serves as an intermediate in the synthesis of other phosphorus-containing additives.