Sodium tripolyphosphate (STPP, sometimes STP or sodium triphosphate or TPP ) with formula Na5P3O10, is a of . Sodium tripolyphosphate (STPP, sometimes STP or sodium triphosphate or TPP ) with formula Na5P3O10, is a of . It is the sodium of .Used as one of the main auxiliaries for synthetic detergent, synergist for soap; water softener, tanning agent for leather making, auxiliary for dyeing; As an ...