Process for improving characteristics of a polyamide
AssigneeE. I. Du Pont de Nemours and Company
InventorsBennett Ray Baird, David Malcolm Lewis, Kamleshkumar Chunilal Patel
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Abstract
A process for improving characteristics such as, whiteness retention, degradation, and dyeability of a polyamide by contacting the polyamide with thiocyanate. A polyamide produced by the process has improved dyed color depth, dyed color uniformity, hue, elimination of light dyeing ends, protection of dye sites from degradation, protection from UV degradation, reduced yellowing or oxidation, and/or resistance to loss of dyeability.
Claims20
A process for improving characteristics of a polyamide having X gram equivalents of amine end groups per 1,000 kg of polyamide, comprising contacting the polyamide or a salt useful to form the polyamide, prior to dyeing or other treatment that makes at least a portion of the amine end groups unavailable for subsequent dyeing, with a thiocyanate or reagent that provides thiocyanate, such that the polyamide after contacting or the polyamide formed from the salt contains Y gram equivalents of thiocyanate groups that protect the amine end groups, such that about 0.001<Y/X<about 1.5.
A polyamide having improved characteristics, wherein the polyamide contains terminal amine dye sites protected by thiocyanate groups.
A composition comprising a polyamide salt solution and a thiocyanate.
A process for improving characteristics of a polyamide, comprising contacting a polyamide having amine end groups with a thiocyanate, such that the polyamide after contacting contains up to about a stoichiometric amount of thiocyanate group based on the amine groups.
A process for improving dyeability characteristics of a polyamide, comprising contacting a polyamide prior to heat-setting or dyeing, with an amount of thiocyanate effective to protect dye-sites of the polyamide.
A process for improving characteristics of a polyamide, comprising contacting a polyamide salt with a thiocyanate, and polymerizing the salt to form a polyamide.
A process for improving characteristics of a polyamide fiber, yarn, film, tow, fabric, molded article, or garment comprising contacting the fiber, yarn, film, tow, fabric, molded article, carpet, garment or other article prior to any dyeing or other treatment that makes the amine end groups unavailable for subsequent dyeing, with a thiocyanate.
Dependencies are inferred from the claim text.