Polysorbate 80, or Tween 80, is the abbreviation of “polyoxyethylene (20) sorbitan monooleate”, is a nonionic surfactant and emulsifier commonly used in food (with the European food additive number E433) and cosmetics mainly due to its ability to mix water-based and oil-based ingredients well (with a high approximate HLB value 15).

http://www.chinafooding.com/Sorbitan_Monostearate