Method of making a metal terephthalate polymer
View Patent ↗A method of making a metal-terephthalate polymer from polyester ethylene terephthalate includes reacting polyester ethylene terephthalate with a metal compound in a non-aqueous melt environment at an elevated temperature. The elevated temperature will be greater than 270° C., and preferably rises to a temperature of about 520° C. The method is preferably carried out at a low pressure. The method may be used in the recycling of passenger vehicle tire shreds to produce a carbon black rrich ppowder that is enriched in the metal-terephthalate polymer.
1. A method of making a metal-terephthalate polymer from polyester ethylene terephthalate comprising:
establishing said metal-terephthalate polymer by reacting said polyester ethylene terephthalate with at least one material selected from the group consisting of polyvalent metal and a metal compound in a first reaction zone which provides a non-aqueous melt environment at temperatures between about 270° C. and 380° C., and
subsequently introducing the reaction product of said first reaction zone into a second reaction zone for processing at about 400° C. to 600° C.
2. The method of claim 1 including getting to said first reaction zone temperatures at a ramp rate of about 10° C. per minute to 100° C. per minute.
3. The method of claim 2 including
said ramp rate portion of said reaction occupying about 5 percent to 50 percent of said reaction time.
4. The method of claim 1 including
said reaction taking about 15 to 315 minutes.
5. The method of claim 1 including
said reaction taking about 25 to 65 minutes.
6. The method of claim 1 including
providing said metal compound in the form of a metal hydroxide.
7. The method of claim 1 including
selecting said metal from the group consisting of Ca, Mg, Al, Se, Fe, Zn, Sr, and Ba.
8. The method of claim 1 including
selecting said metal from the group consisting of Mg, Ca, and Fe.
9. The method of claim 1 including
employing magnesium as said metal.
10. The method of claim 1 including
employing calcium as said metal in the form of a compound selected from the group consisting of CaO, CaCO 3 , CaSO 4 , and Ca(OH) 2 .
11. The method of claim 1 including
employing Fe as said metal.
12. The method of claim 1 including
employing passenger vehicle tires as the source of said polyester ethylene terephthalate.
13. The method of claim 12 including
employing said passenger vehicle tires in the form of tire shreds.
14. The method of claim 12 including
adding Mg as said metal and making Mg(OH) 2 and MgO in situ.
15. The method of claim 12 including
adding a metallic compound and reacting it with said polyester ethylene terephthalate to produce said metal-terephthalate polymer.
16. The method of claim 1 including
adding said metal in a form selected from the group consisting of the metal, a metal oxide, a metal oxide precursor, and a metal carbonate.
17. The method of claim 16 including
making said metallic compound oxide or hydroxide in situ from a material selected from the group consisting of a carbonate, a sulfide, a sulfate, and a metallic material.
18. The method of claim 1 including creating by said method a metal-terephthalate polymer crystalline material.
19. The method of claim 18 including creating said metal-terephthalate polymer in elongated friable crystals.
20. The method of claim 19 including
adding carbon black to said reaction in order to further reduce the size of said metal-terephthalate polymer crystals produced by said reaction.
21. The method of claim 1 including
said reaction employing carbon black from said tire shreds to facilitate said reaction and subsequent crystal formation.
22. The method of claim 1 including
completing said method at a temperature from about 450° C. to 500° C.
23. The method of claim 1 including
completing said method at a temperature below 520° C.
24. The method of claim 1 including
effecting said reaction at a pressure of about 5 psia to 30 psia.
25. The method of claim 1 including
effecting said reaction at a pressure of about 10 psia to 15 psia.
26. The method of claim 1 including
initiating said reaction in a first reaction zone and completing the reaction in a second reaction zone.
27. The method of claim 26 including
injecting oxygen into said second reaction zone.
28. The method of claim 1 including
employing said method as a continuous process.
29. The method of claim 1 including
employing said process as a batch process.
30. The method of claim 27 including
effecting said oxygen introduction into said second reaction zone in a counterflow direction with respect to the direction from which materials enter said second reaction zone from said first reaction zone.
31. The method of claim 27 including
introducing said oxygen in air, and
said oxygen introduction serving to heat said second reaction zone in order to react with residual fragments from polyester ethylene terephthalate and strip other polyester ethylene terephthalate fragments from reaction products.
32. The method of claim 27 including
effecting said oxygen injection in air to provide energy by reacting with residual polyester ethylene terephthalate fragments.
33. The method of claim 30 including
effecting by said air introduction cooling of the reaction product due to counterflow of air to exiting product.
34. The method of claim 33 including
introducing steam into said second reaction zone along with air to cool the reaction products and facilitate reactions at a volumetric rate that is about 10 percent and 100 percent of the combined air and nitrogen rates.
35. The method of claim 1 including
said first reaction zone heated at a ramp rate of about 10° C. per minute to 100° C. per minute, and
providing a hold temperature in the range of about 270° C. to 380° C.
36. The method of claim 35 including
providing a hold time in said first reaction zone of about 10 minutes to 300 minutes.
37. The method of claim 35 including
said hold time being about 15 minutes to about 120 minutes.
38. The method of claim 35 including
said hold time being about 20 minutes to 60 minutes.
39. The method of claim 26 including delivering the reaction product from said pyrolysis to said second reaction zone as a flowable semi-solid.
40. The method of claim 1 including
employing as a polyester ethylene terephthalate source at least one material selected from the group consisting of polyester ethylene terephthalate bottles and polyester ethylene terephthalate fibers.
41. The method of claim 9 including
employing as a metal source at least one material selected from the group consisting of Mg, MgO, MgCO 3 , MgSO 4 , and Mg(OH) 2 .
42. The method of claim 8 including
employing as a metal source at least one material selected from the group consisting of CaO, CaCO 3 , CaSO 4 , and Ca(OH) 2 .
43. The method of claim 26 including
completing the production and purification of metal-terephthalate polymer in said second reaction zone.
44. The method of claim 39 including
said reaction product entering said second reaction zone at about 350° C. to 400° C.
45. The method of claim 43 including
returning unreacted polyester ethylene terephthalate fragments from said second reaction zone to said first reaction zone with the gases from second reaction zone.
46. The method of claim 26 including
returning from said second reaction zone to said first reaction zone air employed to heat said second reaction zone.
47. The method of claim 32 including
employing an auger in said second reactor zone to control residence time and move the reaction product countercurrent to the injected air.
48. The method of claim 1 including
monitoring of polyester ethylene terephthalate and metal-terephthalate polymer in the reaction product by thermo gravimetric analysis to determine purity of metal-terephthalate polymer reaction product.