Efficient combined method of selective dissolution and evaporation for recycling waste polyvinylbutyral films

A facile combined method of selective dissolution and evaporation method was developed to recycle the waste plasticised polyvinylbutyral (PVB) films, in which ethyl acetate was employed as a solvent and decolourising reagent. It has been found that the pigment and plasticiser are soluble in ethyl acetate, and PVB films become transparent and achromatous after dissolution–decolourisation. The optimised decolourising time and the ratio of liquor to material in each run are 40 min and 30∶1 respectively; and the optimised decolourisation times are 3. The solvent, pigment and plasticiser were also successfully recycled by reduced pressure evaporation. Ethyl acetate was recycled effectively under conditions of 55°C and 0·07 MPa (vacuum), and the separation for pigment and plasticiser was achieved at 230°C under 0·08 MPa (vacuum). Furthermore, the decolourisation process was detected to show no effect on the constitution and structure of PVB.