Doverphos 4-HR Plus Trisnonylphenyl phosphite ICC Industries-Dover Antioxidant >> Phosphite Coatings >> Powder Coatings Coil Coating Powder coating Trisnonylphenylphosphite. Used as an antioxidant in paints and coatings. Antioxidants can be added to powder and coil coating formulations to prevent discoloration and loss of physical properties. Contains 1.0% triisopropanolamine. Trisnonylphenylphosphite containing triisopropanolamine. Used as an antioxidant in powder and coil coating formulations. Prevents discoloration and loss of physical properties.