Process for extracting polyester from an article

Abstract

A process for extracting polyester from an article using a solvent system using a compound according to Formula I is described, where ##STR00001##
wherein R.sub.1 and R.sub.2 are each independently selected from: hydrogen, alkyl, alkenyl, alkynyl, aryl or alkoxy groups; R.sub.3 to R.sub.12 are each independently selected from: hydrogen, alkyl, alkenyl, alkynyl, aryl or alkoxy groups; and each of a to e is a carbon atom, wherein the total linear chain length of a-b-c-d-e is in the range of 2 to 5 carbons.

Claims

1. A process for extracting polyester from an article using a solvent system comprising a compound according to Formula I ##STR00003## wherein R.sub.1 and R.sub.2 are each independently selected from: hydrogen, alkyl, alkenyl, alkynyl, aryl or alkoxy groups; R.sub.3 to R.sub.12 are each independently selected from: hydrogen, alkyl, alkenyl, alkynyl, aryl or alkoxy groups; and each of a to e is a carbon atom, wherein the total linear chain length of a-b-c-d-e is in the range of 2 to 5 carbons.

2. A process according to claim 1, wherein the article is fabric.

3. A process according to claim 1, wherein the article is clothing.

4. A process according to claim 1, wherein the article is plastics bottles.

5. A process according to claim 1, wherein the polyester is selected from: Polyglycolic acid (PGA), Polylactic acid (PLA), Polycaprolactone (PCL), Polyethylene adipate (PEA), Polyhydroxyalkanoate (PHA), Polyethylene terephthalate (PET), Polybutylene terephthalate (PBT), Polytrimethylene terephthalate (PTT), Polyethylene naphthalate (PEN) or combination thereof.

6. A process according to a claim 5, wherein the polyester is polyethylene terephthalate.

7. A process according to claim 1, wherein the solvent system is homogeneous.

8. A process according to claim 1, wherein the solvent system comprises one or more compounds according to Formula I in an amount in the range 30% to 100% by mass of the total mass of the composition.

9. A process according to claim 8, wherein the solvent system comprises one or more compounds according to Formula I in an amount of at least 90% by mass of the total mass of the solvent system.

10. A process according to claim 1, wherein the solvent system has a temperature in the range of 70 C. to 110 C.

11. A process according to claim 1, wherein the article is exposed to the solvent system for a period of time in the range of 1 to 2 hours.

12. A process according to claim 1, wherein R.sub.1 and R.sub.12 are each independently hydrogen or an alkyl group.

13. A process according to claim 12, wherein R.sub.1 and R.sub.2 are both methyl groups.

14. A process according to claim 12, R.sub.3 to R.sub.12 are hydrogen.

15. A process according to claim 1, wherein the total linear chain length of a-b-c-d-e is 2 carbons.

16. A process according to claim 1, further comprising a separation step adapted to remove dissolved polyester from the whole or part of the solvent system.

17. A composition comprising one or more compounds according to Formula I, for extracting polyester from an article, wherein the Formula I comprises ##STR00004## wherein R.sub.1 and R.sub.2 are each independently selected from: hydrogen, alkyl, alkenyl, alkynyl, aryl or alkoxy groups; R.sub.3 to R.sub.12 are each independently selected from: hydrogen, alkyl, alkenyl, alkynyl, aryl or alkoxy groups; and each of a to e is a carbon atom, wherein the total linear chain length of a-b-c-d-e is in the range of 2 to 5 carbons.

18. A composition according to claim 17, wherein the article is a fabric.

19. A composition according to claim 18, wherein the article is clothing.

Description

EXAMPLES

Example 1

(1) Poly(ethylene terephthalate) (PET) (Sigma-Aldrich, >99%, 3.0 g) was added to 40 mL of 1,3-dimethylimidazolidinone (DMI) (Sigma-Aldrich, >98%) in a 250 mL glass beaker on a hotplate held at 80 C. The mixture was heated to 95 C. for 2 hours, after which it was removed from the heat and hot filtered to yield 0.26 g of undissolved solid. The hot solution began to gelatinize at approximately 50 C. and after cooling to room temperature gradually separated into a liquid phase and a solid gelatinous phase. The phases were separated by conventional filtration and the filter cake was washed with 25 mL acetone followed by three washes each of 25 mL deionized water. The resultant damp white solid (4.2 g) was collected, transferred to a vacuum desiccator over silica gel and dried to constant weight to yield 2.42 g (81% yield) of a powdery white solid whose infra-red spectrum correlated with that of virgin poly(ethylene terephthalate).

Example 2

(2) A sample of a white polyester shirt (17.75 g) was cut into 1 cm.sup.2 squares and added to 80 mL of 1,3-dimethylimidazolidinone (DMI) in a 500 mL glass beaker on a hotplate held at 80 C. The mixture was heated to 95 C. with occasional stirring to prevent localized decomposition of polymer at surface hot spots. After 1 hour, the mixture was removed from the heat and hot filtered to yield 4.3 g of undissolved solid. The hot solution began to gelatinize at approximately 50 C. and after cooling to room temperature gradually separated into a liquid phase and a solid gelatinous phase. The phases were separated by conventional filtration and the filter cake was washed with 25 mL acetone followed by three washes each of 25 mL deionized water. The resultant damp white solid (17.59 g) was collected, transferred to a vacuum desiccator over silica gel and dried to constant weight to 13.1 g (74% yield) of a powdery white solid whose infra-red spectrum correlated with that of virgin poly(ethylene terephthalate).

Example 3

Dissolution of PET in Butyl Benzoate

(3) To 200mL butyl benzoate at 100 C. was added, with stirring, 25 g shredded textile (60 wt. % poly(ethylene terephthalate), 40 wt. % cotton). The mixture was stirred with heating for 2 hours. At the conclusion of this period, solid material was filtered off and the hot filtrate was collected and cooled to room temperature, whereupon a quantity of white solid precipitate formed. The filtrate was diluted with 200 mL isopropyl alcohol and filtered using a Buchner funnel. The resultant white solid was washed with a further 100 mL isopropyl alcohol followed by 200 mL deionized water and dried to constant weight in a vacuum desiccator to yield 4 g (26% yield) of crystalline powdery solid, mp 253-256 C.

Example 4

Dissolution of PET in Butyl Benzoate

(4) To 200 mL butyl benzoate at 100 C. was added, with stirring, 25 g shredded textile (60wt. % poly(ethylene terephthalate), 40 wt. % cotton). The mixture was stirred with heating for 2 hours. At the conclusion of this period, solid material was filtered off and the hot filtrate was collected and cooled to room temperature, whereupon a quantity of white solid precipitate formed. The filtrate was diluted with 200 mL isopropyl alcohol and filtered using a Buchner funnel. The resultant white solid was washed with a further 100 mL isopropyl alcohol followed by 200 mL deionized water and dried to constant weight in a vacuum desiccator to yield 4 g (26% yield) of crystalline powdery solid, mp 253-256 C.

Example 5

Dissolution of PET in Benzyl Acetate

(5) To 25 mL benzyl acetate at 100 C. was added, with stirring, 2.5 g shredded textile (60 wt. % poly(ethylene terephthalate), 40 wt. % cotton). The mixture was stirred with heating for 2 hours. At the conclusion of this period, solid material was filtered off and the hot filtrate was collected and cooled to room temperature, whereupon a quantity of white solid precipitate formed. The solid was collected by vacuum filtration and washed with 25 mL isopropyl alcohol followed by 50 mL deionized water. The solid residue was dried to constant weight in a vacuum desiccator over P.sub.2O.sub.5 to yield 0.85 g (57% yield) of white powder, mp 262-266 C.

Example 6

Dissolution of PET in Benzaldehyde

(6) To 25 mL benzaldehyde at 90 C. was added, with stirring, 2.5 g shredded textile (60 wt. % poly(ethylene terephthalate), 40 wt. % cotton). The mixture was stirred with heating for 2 hours. At the conclusion of this period, solid material was filtered off and the hot filtrate was collected and cooled to room temperature, whereupon a quantity of white solid precipitate formed. The solid was collected by vacuum filtration and washed with 25 mL industrial methylated spirits followed by 50 mL deionized water. The solid residue was dried to constant weight in a vacuum desiccator over P.sub.2O.sub.5 to yield 0.71 g (47% yield) of white powder, mp 260-265 C.

Example 7

Dissolution of PET in Dipropylene Glycol Methyl Ether Acetate

(7) To 25 mL dipropylene glycol methyl ether acetate at 90 C. was added, with stirring, 2.5 g shredded textile (60 wt. % poly(ethylene terephthalate), 40 wt. % cotton). The mixture was stirred with heating for 2 hours. At the conclusion of this period, solid material was filtered off and the hot filtrate was collected and cooled to room temperature, whereupon a small quantity of white solid precipitate formed. The solid was collected by vacuum filtration and washed with 25 mL industrial methylated spirits followed by 50 mL deionized water. The solid residue was dried to constant weight in a vacuum desiccator over P.sub.2O.sub.5 to yield 0.22 g (15% yield) of white powder, mp 262-265 C.

Example 8

Dissolution of PET in Propylene Glycol Benzyl Ether Acetate

(8) To 25 mL dipropylene glycol methyl ether acetate at 100 C. was added, with stirring, 2.5 g shredded textile (60 wt. % poly(ethylene terephthalate), 40 wt. % cotton). The mixture was stirred with heating for 2 hours. At the conclusion of this period, solid material was filtered off and the hot filtrate was collected and cooled to room temperature, whereupon a small quantity of white solid precipitate formed. The solid was collected by vacuum filtration and washed with 25 mL isopropyl alcohol followed by 50 mL deionized water. The solid residue was dried to constant weight in a vacuum desiccator over P.sub.2O.sub.5 to yield 0.58 g (39% yield) of off-white powder, mp 254-259 C.