Doverphos 4 is trisnonylphenyl phosphite (TNPP). It is an aryl phosphite with high molecular weight and low phosphorus content. Doverphos 4 is an effective liquid phosphite heat stabilizer for a wide variety of applications. These include polyolefin, acrylics, adhesives, elastomers, nylon, polycarbonate, polyurethanes, polystyrene, PVC, coatings, ABS, and polyethylene terephthalate. The effectiveness of Doverphos 4 is enhanced by the addition of other stabilizers like hindered phenol. Typical use levels range from 0.05 to 3.00% for most applications. Doverphos 4 is sanctioned under FDA regulations for use in many applications.