Process for separating polyethylene terephthalate from polyvinyl chloride
US5252614A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 11, 1991 |
| Grant date | Oct 12, 1993 |
| Priority date | — |
| Expiry date | Dec 11, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02W30/62
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
This invention reveals a process for recovering polyethylene terephthalate flakes from a recycle stream containing polyethylene terephthalate flakes and polyvinyl chloride flakes which comprises: (1) treating the recycle stream with (a) at least one inorganic base selected from the group consisting of sodium hydroxide and potassium hydroxide 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.degree. while maintaining the contact angle of the polyvinyl chloride flakes above a value of about 45.degree.; (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 to the surface of the aqueous mixture and allowing the polyethylene terephthalate flakes to sink to the bottom of the aqueous mixture; and (5) removing the polyvinyl chloride flakes from the surface of the aqueous mixture and…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.