Process for recovering polyester from polyester/wool blend

Patent metadata

Field	Value
Publication number	US-9932456-B2
Application number	US-201515102004-A
Country	US
Kind code	B2
Filing date	Jan 6, 2015
Priority date	Jan 6, 2014
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

The present disclosure relates to a process for recovering a polyester component and products of a non-polyester component from a fabric containing a polyester blend. The polyester component of the present disclosure is polyethylene terephthalate and the non-polyester component is wool. The process includes hydrolyzing the article using at least one hydrolyzing agent to convert the non-polyester component into products of the non-polyester component and release the polyester component.

First claim

The invention claimed is:

1. A process for recovering, from an article comprising a polyester blend comprising a polyester component and a non-polyester component, the polyester component and products of the non-polyester component wherein said non-polyester component is wool; said process comprising hydrolyzing said article using at least one hydrolyzing agent having pH ranging from 7 to 14 to convert said non-polyester component into products of the non-polyester component, followed by washing to remove said alkali and said products of said non-polyester component and drying to recover the polyester component wherein said hydrolyzing agent is an alkali; and
wherein, said alkali has a concentration ranging from 3 to 5% (w/v).

2. The process as claimed in claim 1 , wherein said polyester component is polyethylene terephthalate (PET).

3. The process as claimed in claim 1 , wherein said step of hydrolyzing said article includes a pre-step of shredding said article.

4. The process as claimed in claim 1 , wherein said step of hydrolyzing said article is carried out at a temperature ranging from 90 to 160° C. for a time period ranging from 10 to 90 minutes and at a pressure ranging from 5 to 25 psi.

5. The process as claimed in claim 1 , wherein said step of hydrolyzing said article is carried out in an autoclave.

6. The process as claimed in claim 1 , wherein one alkali is selected from the group consisting of sodium hydroxide, sodium carbonate, calcium hydroxide and calcium carbonate.

7. The process as claimed in claim 1 , further includes incubating the article, after the step of hydrolyzing, with at least one enzyme selected from the group consisting of lipase and protease to further separate and recover the polyester component and the non-polyester component.

8. The process as claimed in claim 7 , wherein said step of incubating is carried out in the presence of a buffer having strength ranging from 80 to 120 mM and pH ranging from 6.0 to 8.0 for an incubation period ranging from 15 to 48 hours at a temperature ranging from 40 to 60° C.; said buffer being sodium phosphate.

9. The process as claimed in claim 7 , wherein said step of incubating includes stirring at a speed ranging from 150 to 250 rpm.

10. The process as claimed in claim 7 , wherein said enzyme is a combination of lipase and protease and has a concentration ranging from 1 to 10 g/L.

Assignees

• Reliance Industries Ltd

Inventors

• Rangaswamy Vidhya
• Srivastava Anurag
• Balachandran Vijai
• Joshi Harshvardhan

Classifications

• C08J11/04 Primary

  of polymers · CPC title

• C08J11/14

  by treatment with steam or water · CPC title

• D06M16/003

  with enzymes or microorganisms · CPC title

• Y02P20/143

  the feedstock being recycled material, e.g. plastics · CPC title

• C08J11/105 Primary

  by treatment with enzymes · CPC title