Method for purifying contaminated polymers

Patent metadata

Field	Value
Publication number	US-9695259-B2
Application number	US-201615190238-A
Country	US
Kind code	B2
Filing date	Jun 23, 2016
Priority date	Jun 30, 2015
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

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

First claim

What is claimed is:

1. A method for purifying a reclaimed polymer comprising:
a. Obtaining the reclaimed polymer wherein said reclaimed polymer is selected from the group consisting of post-consumer use polymers, post-industrial use polymers, and combinations thereof;
b. Contacting the reclaimed polymer 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 polymer;
c. Dissolving the extracted reclaimed polymer 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 polymer solution;
d. Separating a polymer from said polymer solution;

wherein said second fluid solvent is the same chemical composition or a different chemical composition as the first fluid solvent.

2. The method of claim 1 , wherein the polymer is separated from said polymer solution at a temperature from about 0° C. to about 220° C. and a pressure from about 0 psig (0 MPa) to 2,000 psig (13.79 MPa).

3. The method of claim 1 , wherein undissolved contamination is separated from said polymer solution using decantation, sedimentation, centrifugation, field-flow fractionation, and combinations thereof.

4. The method of claim 1 , wherein the reclaimed polymer is post-consumer recycle derived polymer.

5. e method of claim 1 , wherein said reclaimed polymer is polystyrene.

6. The method of claim 1 , wherein said reclaimed polymer is poly(dimethylsiloxane).

7. The method of claim 1 , wherein said reclaimed polymer is a polypropylene homopolymer or a primarily polypropylene copolymer.

8. The method of claim 1 , wherein said reclaimed polymer is a polyethylene homopolymer or a primarily polyethylene copolymer.

9. The method of claim 1 , wherein said fluid solvent has a standard boiling point less than about 0° C. and greater than about −45° C. and a standard enthalpy change of vaporization of less than about +25kJ/mol.

10. The method of claim 1 , wherein said fluid solvent is selected from the group consisting of olefinic hydrocarbons, aliphatic hydrocarbons, and mixtures thereof.

11. The method of claim 10 , wherein said aliphatic hydrocarbon is selected from the group consisting of C 1 -C 6 aliphatic hydrocarbons and mixtures thereof.

12. The method of claim 10 , wherein said aliphatic hydrocarbons and mixtures thereof is comprised of primarily C 4 aliphatic hydrocarbons.

13. The method of claim 10 , wherein said fluid solvent consists essentially of C 4 liquefied petroleum gas.

14. The method of claim 11 , wherein said fluid solvent is n-butane, butane isomers, or mixtures thereof.

15. The method of claim 1 , wherein said temperature in steps b and c is from about 110° C. to about 170° C.

16. The method of claim 1 , wherein said reclaimed polymer is polypropylene and said pressure in step b is from about 1,100 psig (7.58 MPa) to about 2,100 psig (14.48 MPa).

17. The method of claim 1 , wherein said pressure in step b is less than about 1,100 psig (7.58 MPa).

18. The method of claim 1 , wherein said reclaimed polymer is polyethylene and said pressure in step b is from about 1,100 psig (7.58 MPa) to about 5,500 psig (37.92 MPa).

19. The method of claim 1 , wherein said reclaimed polymer is polypropylene and said pressure in step c is greater than about 1,100 psig (7.58 MPa).

20. The method of claim 1 , wherein said reclaimed polymer is polypropylene and said pressure in step c is greater than about 2,100 psig (14.48 MPa).

21. The method of claim 1 , wherein said reclaimed polymer is polyethylene and said pressure in step c is greater than about 4,500 psig (31.03 MPa).

22. The method of claim 1 , wherein said reclaimed polymer is polyethylene and said pressure in step c is greater than about 5,500 psig (37.92 MPa).

Assignees

• Procter & Gamble

Inventors

• Layman John Moncrief
• Gunnerson Maggie
• Schonemann Hans
• Williams Kara

Classifications

• C08J2325/06

  Polystyrene · CPC title

• C08J2323/12

  Polypropene · CPC title

• C08J2323/10

  Homopolymers or copolymers of propene · CPC title

• C08J2323/08

  Copolymers of ethene (C08J2323/16 takes precedence) · CPC title

• C08J2323/06

  Polyethene · CPC title