Polyester textile waste recycling
A method for recycling polyester from a polyester textile comprises the steps of: providing said polyester textile soaked in a mixture comprising a solvent and a catalyst, providing and maintaining a temperature of said mixture comprising said polyester textile within a range of 80-240° C. during depolymerization of polyester in said polyester textile and wherein, in said step of providing said polyester textile soaked in said mixture, said catalyst of said mixture comprises calcium oxide. A catalyst may be used for depolymerization of polyester in a polyester textile, wherein the catalyst comprises calcium oxide.
1. A method for recycling polyester from a polyester textile, wherein said method comprises the steps of:
providing said polyester textile soaked in a mixture comprising a solvent and a catalyst;
providing and maintaining a temperature of said mixture comprising said polyester textile within a range of 80-240° C. during depolymerization of polyester in said polyester textile; and
recovering molecules, at least some of said recovered molecules having a molecular weight lower than 600 g/mol,
wherein, in said step of providing said polyester textile soaked in said mixture, said catalyst of said mixture comprises calcium oxide.
2. The method according to claim 1 , wherein said step of maintaining the temperature of said mixture comprising polyester textile lasts until at least 20% of the polyester in said polyester textile is depolymerized to molecules with a molecular weight lower than 600 g/mol, or at least 50% of the polyester in said polyester textile is depolymerized to molecules with a molecular weight lower than 600 g/mol, or at least 80% of the polyester in said polyester textile is depolymerized to molecules with a molecular weight lower than 600 g/mol.
3. The method according to claim 1 , wherein said temperature is within a range of 80-170° C., or within a range of 100-150° C.
4. The method according to claim 1 , wherein, in said step of maintaining said temperature of said mixture comprising said polyester textile, said temperature is maintained for 10-300 min, or for 30-240 min, or for 60-120 min.
5. The method according to claim 1 , wherein said solvent comprises an alcohol or a diol.
6. The method according to claim 1 , wherein
said polyester textile comprises at least 10% polyester, or at least 25% polyester, or at least 50% polyester, or at least 75% polyester, or
said polyester textile comprises 100% polyester.
7. The method according to claim 1 , wherein said polyester textile further comprises natural fibers and/or additional synthetic fibers.
8. The method according to claim 1 , wherein
said polyester is aromatic polyester; and
said depolymerized polyester includes at least one of dimethyl, terephthalate, ethylene glycol, 1,3-propanediol, 1,4-butanediol, ethyl methyl terephthalate, dimers of the aromatic polyester, and trimers of aromatic polyester.
9. The method according to claim 1 , wherein said catalyst further includes
an oxide of any periodic table group 2 metal, or
an oxide of any lanthanide metal.
10. The method according to claim 1 , wherein said catalyst is an oxide having a general formula CaO-xO-yO, where x is any periodic table group 2 metal and where y is any lanthanide metal.
11. The method according to claim 1 , wherein said depolymerization is performed in an autoclave.
12. The method according to claim 8 , wherein said method further comprises the step of:
recovering said at least one of dimethyl terephthalate, ethylene glycol, 1,3-propanediol, 1,4-butanediol, ethyl methyl terephthalate, dimers of aromatic polyester, and trimers of aromatic polyester.
13. A method for depolymerization of polyester in a polyester textile, wherein said method comprises:
providing said polyester textile soaked in a mixture comprising a solvent and a catalyst; and
providing and maintaining a temperature of said mixture comprising said polyester textile within a range of 80-240° C. during depolymerization of polyester in said polyester textile,
wherein said catalyst comprises calcium oxide.
14. The method according to claim 13 , wherein said catalyst further comprises
an oxide of any periodic table group 2 metal, or
an oxide of any lanthanide metal.
15. The method according to claim 13 , wherein said catalyst is an oxide having a general formula CaO-xO-yO, where x is any periodic table group 2 metal and where y is any lanthanide metal.
16. The method according to claim 13 , wherein said temperature is within a range of 80-170° C., or within a range of 100-150° C.
17. The method according to claim 13 , wherein, in said step of maintaining said temperature of said mixture comprising said polyester textile, said temperature is maintained for 10-300 min, or for 30-240 min, or for 60-120 min.
18. The method according to claim 13 , wherein said solvent comprises an alcohol or a diol.
19. The method according to claim 13 , wherein
said polyester textile comprises at least 10% polyester, or at least 25% polyester, or at least 50% polyester, or at least 75% polyester, or
said polyester textile comprises 100% polyester.
20. The method according to claim 13 , wherein said polyester textile further comprises natural fibers and/or additional synthetic fibers.