Method For Purifying Contaminated Polyethylene

摘要

A method for purifying reclaimed polyethylene, such as polyethylene reclaimed from post-consumer use or post-industrial use, is disclosed. The method involves obtaining the reclaimed polyethylene and contacting it at an elevated temperature and pressure with a fluid solvent to produce an extracted reclaimed polyethylene. The extracted reclaimed polyethylene is dissolved in a solvent at an elevated temperature and pressure to produce a polyethylene solution, which is purified at an elevated temperature and pressure by contacting the polyethylene solution with solid media to produce a purer polyethylene solution. A purer polyethylene is then separated from the purer polyethylene solution.

主权项

1. A method for purifying reclaimed polyethylene comprising:
a. Obtaining the reclaimed polyethylene wherein said reclaimed polyethylene is selected from the group consisting of post-consumer use polymers, post-industrial use polymers, and combinations thereof; b. Contacting the reclaimed polyethylene at a temperature from about 80° C. to about 220° C. and at a pressure from about 150 psig (1.03 MPa) to about 15,000 psig (103.42 MPa) with a first fluid solvent having a standard boiling point less than about 70° C., to produce an extracted reclaimed polyethylene; c. Dissolving the extracted reclaimed polyethylene in a solvent selected from the group consisting of the first fluid solvent, a second fluid solvent, and mixtures thereof, at a temperature from about 90° C. to about 220° C. and a pressure from about 350 psig (2.41 MPa) to about 20,000 psig (137.90 MPa) to produce a polyethylene solution; d. Purifying said polyethylene solution at a temperature from about 90° C. to about 220° C. and at a pressure from about 350 psig (2.41 MPa) to about 20,000 psig (137.90 MPa) by contacting said polyethylene solution with solid media to produce a purer polyethylene solution; and e. Separating a purer polyethylene from said purer polyethylene solution;wherein said second fluid solvent has the same chemical composition or a different chemical composition as the first fluid solvent.