Method for obtaining wax from recycled polyethylene

• US 9,200,130 B2
• Filed: 08/07/2012
• Issued: 12/01/2015
• Est. Priority Date: 08/07/2012
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: D'Amato, Michael J., Faucher, Santiago, Lincoln, Timothy L., Darabi, Ali, Duque, Rosa
• Primary Examiner(s): Bullock, In Suk
• Assistant Examiner(s): Jeong, Youngsul
• Application Number:
  US13/569,036
• Publication Number:
  US 20140046102A1
• Time in Patent Office: 1,211 Days
• Field of Search: 585/17, 585/241
• US Class Current: 1/1
• CPC Class Codes: C08J 11/00 Recovery or working-up of waste materials recovery of plastics B29B17/00; polymerisation processes involving purification or recycling of waste polymers or their depolymerisation products C08B, C08C, C08F, C08G, C08H
• CPC Class Codes: C08J 11/12 by dry-heat treatment only
• CPC Class Codes: C08J 2323/04 Homopolymers or copolymers of ethene
• CPC Class Codes: C08K 5/0083 Nucleating agents promoting the crystallisation of the polymer matrix
• CPC Class Codes: C08K 5/09 Carboxylic acids; Metal salts thereof; Anhydrides thereof
• CPC Class Codes: C08K 5/092 Polycarboxylic acids
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08L 2201/56 Non-aqueous solutions or dispersions
• CPC Class Codes: C08L 2205/24 Crystallisation aids
• CPC Class Codes: C08L 91/06 Waxes
• CPC Class Codes: C08L 91/08 Mineral waxes
• CPC Class Codes: C10G 1/10 from rubber or rubber waste
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

An economical and environmentally friendly method for producing waxes. In particular, the methods use thermolytic degradation concurrently with a distillation process to obtaining distilled waxes from recycled polyethylene. The resulting waxes have desirable properties, such as reduced molecular weight and narrow polydispersity, that makes the waxes useful in various applications.

Claims

1. A process for producing a wax from recycled polyethylene, comprising:

providing an amount of recycled polyethylene;

heating the recycled polyethylene to a high temperature of from about 200 °

C. to about 500 °

C. and under a pressure of from about 1 mmHg absolute to about 100 mmHg absolute to undergo de-polymerization;

degrading the recycled polyethylene to smaller wax fragments having a molecular weight of from about 200 to about 2,000;

concurrently distilling the recycled polyethylene under a pressure of from about 1 mmHg absolute to about 100 mmHg absolute during the de-polymerization to collect and remove the smaller wax fragments.

2. The process of claim 1, wherein the recycled polyethylene is selected from the group consisting of high density polyethylene, linear low density polyethylene, and mixtures thereof.

3. The process of claim 1, wherein the recycled polyethylene is heated to a high temperature of from about 200 to about 500°

C.

4. The process of claim 3, wherein the recycled polyethylene is heated to a high temperature of from about 250 to about 450°

C.

5. The process of claim 4, wherein the recycled polyethylene is heated to a high temperature of from about 350 to about 425°

C.

6. The process of claim 1, wherein the recycled polyethylene has a number average molecular weight of from about 10,000 to about 100,000.

7. The process of claim 6, wherein the recycled polyethylene has a number average molecular weight of from about 30,000 to about 60,000.

8. The process of claim 1, wherein the recycled polyethylene has a polydispersity of from about 1.0 to about 2.0.

9. The process of claim 1, wherein the smaller wax fragments have a molecular weight of from about 300 to about 1000.

10. The process of claim 1, wherein the smaller wax fragments have a polydispersity of from about 1.01 to about 1.5.

11. The process of claim 1, wherein from about 60 to about 80 percent of the recycled wax is converted to the smaller wax fragments.

12. A process for producing a wax from recycled

polyethylene, comprising:

providing an amount of recycled polyethylene, wherein the recycled polyethylene has the following general structure

13. A process for producing a wax from polyethylene, comprising:

providing an amount of polyethylene;

heating the polyethylene to a high temperature of from about 200 °

C. to about 500 °

C. under a pressure of from about 1 mmHg absolute to about 100 mmHg absolute with a vacuum pump to undergo de-polymerization;

stirring the polyethylene during the heating step to degrade the polyethylene to smaller polyethylene fragments having a molecular weight of from about 200 to about 2,000;

concurrently distilling the polyethylene under a pressure of from about 1 mmHg absolute to about 100 mmHg absolute with the vacuum pump during the de-polymerization to collect and remove the smaller polyethylene fragments.

14. The process of claim 13, wherein the polyethylene is stirred at a speed of from about 100 to about 200 RPM.

15. The process of claim 14, wherein the polyethylene is stirred at a speed of from about 125 to about 175 RPM.

16. The process of claim 13, wherein the polyethylene is heated under a pressure of from about 1 mmHg absolute to about 100 mmHg absolute.

17. The process of claim 16, wherein the polyethylene is heated under a pressure of from about 1 mmHg absolute to about 100 mmHg absolute.