method for separating polyethylene terephthalate from polyvinyl chloride.

摘要

The process comprises: (1) treating the recycle stream with (a) at least one inorganic base and (b) at least one nonionic surfactant under conditions and for a time sufficient to decrease the contact angle of the polyethylene terephthalate flakes with water below a value of 25 DEG while maintaining the contact angle of the polyvinyl chloride flakes above a value of about 45 DEG ; (2) adding the treated recycle stream to water, to form an aqueous mixture containing the treated polyethylene terephthalate flakes and treated polyvinyl chloride flakes; (3) agitating the aqueous mixture to allow the polyvinyl chloride flakes to come in contact with gas bubbles; (4) allowing the polyvinyl chloride flakes to float and the polyethylene terephthalate flakes to sink; and (5) removing the polyvinyl chloride flakes from the surface of the aqueous mixture and removing the polyethylene terephthalate flakes from the bottom of the aqueous mixture.