The three phase separation was obtained for the ternary system of ethylene glycol diacetate (EGDA) + methylcyclohexane (MCH) + polystyrene (PS) with the molecular weight (M-w = 4.8 x 10(4) g/mol). A phase equilibrium experiment was carried out to determine binodals and three phase triangles. With decreasing temperature the three phase separation appears at 35.0 degrees C in the two phase region spreading from the EGDA-MCH side protruding a new binodal with a critical point on a composition triangle. The binodal spreading from the EGDA-PS side merges with the binodal from EGDA-MCH side at 34.0 degrees C via a critical point, while the binodal from MCH-PS side merges with the new binodal at 32.9 degrees C. Thus, the binodal surface in a prism diagram of composition triangle and temperature has two saddle points at which a critical line has a minimum. (C) 2016 Elsevier Ltd. All rights reserved.