Product quality indexes Apperance Orange crystal Melting point≥ 65.0% Assay≥ 99.0% Tetramethyl-4-piperidinol≤ 0.5% Purpose: This product is a high-quality inhibitor of the new-generation vinyl monomer to substitute hydroquinone which may cause heavy pollution to the enviroment,and is is widely used in the production of acrylic acid ester,methyl acrylic acid ester and vinyl acetate,as well as chloroethylene,unsaturated polyester and pesticide puma.