Method for removing color from polymeric material
AssigneeBASF SE
InventorsRonnie Ozer, Kevin R. Gerzevske
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Abstract
Color is removed from polymeric material by a method which comprises contacting a dyed or pigmented polymer composition with a non-aqueous extraction solvent comprising a nitrogen containing organic base, an ammonium salt and an alkanol. The present method is readily applied to a process for recycling colored polyamide substrates such as dyed nylon fiber.
Claims21
A process for removing a colorant from a colored polymer composition which process comprises immersing the colored polymer composition into a non-aqueous extraction solvent for a time sufficient to lower the initial CIE Lab color values of the colored polymer composition by 50% or more,
- wherein the non-aqueous extraction solvent is essentially water free, containing less than 5% water by weight based on the total weight of the extraction solvent, and comprises from about 40 to about 98% by weight based on the total weight of the extraction solvent of amine or amide organic base, from about 0.1 to about 20% by weight based on the total weight of the extraction solvent of ammonium salt and from about 0.1 to about 40% by weight based on the total weight of the extraction solvent of C1-24 alcohol, diol or polyol, to produce a decolorized polymer which is then separated from the extraction solvent and colorant.
Dependencies are inferred from the claim text.