Azoic dyeing of leather
AssigneeE. I. Du Pont de Nemours and Company
InventorCatharine Elizabeth Looney
Life of this patent
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Abstract
Dry leather is dyed with azoic dyes without wetting the leather with water by incorporating into the leather the required diazonium component and any required coupling component in a substantially non-aqueous volatile low-viscosity solvent and incorporating into the leather any other materials required for the coupling reaction in such a solvent or as a vapor. The coupling component can be a natural or synthetic phenolic tanning agent employed in tanning the leather. Dye patterns can be applied to the surface of the leather by using a light-sensitive diazonium component and photo-imaging the surface before effecting coupling. Dry leather is dyed by such processes without significant change in properties.
Claims17
An improved process for dyeing leather with azoic dyes without significantly changing the surface or bulk esthetic or physical properties of the leather which comprises interacting within leather a diazonium and a coupling component to form a colored dye wherein the improvement consists essentially of (a) incorporating into substantially dry leather simultaneously or sequentially
- (1) a diazonium component, and
- (2) coupling component as required, in solution in a substantially non-aqueous, volatile, low-viscosity solvent liquid containing less than about 25% water, (b) interacting the diazonium component and a coupling component without wetting the leather with water, and (c) evaporating any remaining solvent liquid from the leather at ambient temperatures.
Dependencies are inferred from the claim text.