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US 4,883,496 AGranted
Process for dyeing crystalline aromatic polyamide fibers with water-insoluble dyes
AssigneeE. I. Du Pont de Nemours and Company
InventorHamid M. Ghorashi
Life of this patent
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Abstract
A process for dyeing crystalline poly(meta-phenylene isophthalamide) fibers with a water-insoluble dye padded onto such fibers by heating with steam at critical temperatures first to activate the dye and thereafter to diffuse it into the fibers.
Claims6
A process for dyeing a tow of crystalline poly-(m-phenylene isophthalamide) filaments comprising the steps of:
- padding onto the surface of the filaments of the tow an aqueous dispersion of 1 to 20 wt. % of a water-insoluble dye material having a dye-activation temperature at or less than about 130.degree. C. and below the glass transition temperature of poly(m-phenylene isophthalamide),
- heating the tow with steam to a temperature below the glass transition temperature of the poly(m-phenylene isophthalamide) but above the dye-activation temperature to activate the dye material on the surface of the filaments of the tow, and thereafter
- heating the tow with steam to a temperature above the glass transition temperature of the poly(m-phenylene isophthalamide) but no more than about 165.degree. C. to diffuse substantially all of the dye material into the filaments of the tow.
A process for dyeing synthetic fibers including the following steps:
- contacting fibers of crystalline poly(m-phenylene isophthalamide) with an aqueous dispersion containing a water-insoluble dye which is activated in steam at a temperature below the glass transition temperature of the fibers,
- heating the fibers with steam at a dye-activation temperature at or less than about 130.degree. C. and below the glass transition temperature of the fibers for a time sufficient to activate the water-insoluble dye on the surface of the fibers, and thereafter
- heating the fibers with steam at a temperature above the glass transition temperature of the fibers for a time sufficient to diffuse the dye material into the fibers.
Dependencies are inferred from the claim text.