SOLVENT FOR POLYSTYRENE, METHOD FOR REDUCING VOLUME OF FOAMED POLYSTYRENE, AND METHOD FOR RECYCLING FOAMED POLYSTYRENE

摘要

PROBLEM TO BE SOLVED: To recycle foamed polystyrene safely, simply, and conveniently by dissolving foamed polystyrene in a solvent mainly comprising at least either a glycol ether compd. or a dialkyl ester of a fatty acid and distilling the resulting soln. to separate polystyrene from the solvent. SOLUTION: Foamed polystyrene is recycled by dissolving it in a solvent mainly comprising at least either a glycol ether compd. represented by formula I (wherein R1 and R2 are a each 1-3C alkyl; and n is 0-4) or a dialkyl ester of a fatty acid represented by formula II (wherein m is 1-4; n is 0-4; and R is H or methyl) and distilling the resulting soln. at a temp. lower than the thermal decomposition point of polystyrene to separate polystyrene from the solvent. Polystyrene can also be separated from the soln. by adding to it water to precipitate polystyrene followed by separation from the soln. In comparison with a conventionally used solvent, d-limonene, which emits a strong citrus odor and has a problem with a low flash point, the solvent of the invention is excellent in dissolving power and enables the recycling of foamed polystyrene environmentally safely.