Chemical compounds and methods for removing dye
OwnerRaymond Berard, Connie Henslerinventors
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Abstract
Chemical compounds and methods for removing dye from polyester fibers, in particular poly(ethylene terephthalate) (“PET”) fibers, is disclosed. The compounds and methods are particularly useful for removing dye from panel fabric made from recycled PET fibers. The method involves contacting the PET with a dye removal compound in a sealable vessel. The contents of the vessel are agitated and heated to achieve an increase in pressure and temperature. Following a cooling down period, the PET is removed and rinsed with water. The dye removal compound includes an aqueous solution of at least one leveling agent.
Claims55
A method for removing dye from polyester comprising:
- a) contacting the polyester with a dye removal composition comprising an aqueous solution of at least one leveling agent to form a mixture;
- b) heating the mixture until it reaches an elevated temperature and a pressure higher than the equilibrium pressure of the dye removal composition at the elevated temperature;
- c) maintaining the mixture at the elevated temperature and pressure for a time interval sufficient to at least partially remove dye from the polyester;
- d) cooling the mixture;
- e) separating the polyester from the mixture;
- and
- f) removing any residual dye removal composition from the polyester.
A method for removing dye from PET comprising:
- a) contacting the PET with a dye removal composition comprising an aqueous solution of one or more of propylene glycol ether, isopropyl alcohol, n-butyl phthalimide and nonyl phenol ethoxylatein to form a mixture;
- b) heating the mixture for about 120 minutes;
- c) maintaining the temperature of the mixture at about 140° C. and the pressure at about 33 psi for a time sufficient to at least partially remove dye from the PET;
- d) cooling the mixture to 30° C. over a period of about 20 minutes to 40 minutes;
- e) separating the PET from the mixture;
- and
- f) rinsing the PET with water.
A composition for removing dye from polyester comprising an aqueous solution of about 2.0 wt % to about 8.0 wt % of at least one leveling agent, based on the total composition.
A device for removing dye from polyester, comprising:
- a sealable vessel;
- and
- a dye removal composition disposed therein, the dye removal composition comprising an aqueous solution of about 2.0 wt % to about 8.0 wt % of at least one leveling agent, based on the total dye removal composition.
Dependencies are inferred from the claim text.