EPS is used widely, but often is single-used, and its light weight, big volume and difficult degradation and other reasons make the white pollution caused by it become increasingly prominent. Therefore, carrying out its recycling research has important practical significance and broad market prospects. Currently, EPS’S key recovery methods include: 1. Recycled polystyrene material with melt extrusion method; 2. Thermal decomposition recovering styrene monomer; 3. Direct recycling and broken into tablets, and then add into new compound to recycle; 4. Using a solvent to recover and making into adhesives. The first method needs large energy, it is very uneconomical .The second method has complex process, large investment in equipment, it costs highly .The third method’s re-use ability is limited and it is not conducive to the health of workers. Now there are literatures about the fourth method both at home and abroad, but mostly failed to promote due to the used solvents is toxic or expensive.
It is an effective and reliable way that using inexpensive low toxic or non-toxic solvent to recycle the waste EPS plastic after rapid defoaming and volume reduction by the means of dissolution, directly get polystyrene materials, and can be easily in-situ treatment the same time. The sources of recovering solvent in the literatures can be divided into two categories: one is natural organic solvents, such as orange oil, Ylang-Ylang oil; the other one is organic chemical solvents, such as benzene, toluene, ethyl benzene, chloroform, ethyl acetate, etc. Where in the use of natural solvent will be susceptible to the limitations of sources of raw materials, and generally smaller solubility. Organic synthetic solvents are generally dissolved efficient, but often susceptible to the limitations of raw material costs and toxicity.