Dyeing of cellulose
AssigneeCourtaulds Limited
InventorJames Martin Taylor
Life of this patent
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Abstract
Dyed cellulosic regenerated elongate members such as fibers are produced by dyeing the regenerated members with a cationic direct dye after formation but before first drying. A method of producing the dyed elongate members comprises forming a dope containing cellulose or a cellulose compound in solution in a solvent, extruding the dope through at least one orifice into a bath containing water to form an elongate extrudate from which solvent is dissolved and/or the cellulose compound is converted to cellulose so as to form the elongate member, dyeing the formed but never dried elongate member with a cationic direct dye and optionally also with an anionic direct dye and then drying for the first time the dyed elongate member.
Claims18
A method of manufacturing a dyed cellulosic regenerated elongate member which includes the steps of:
- (i) forming a dope selected from the group consisting of:
- (a) cellulose in solution in a solvent, and
- (b) a cellulose compound in solution in a solvent;
- (ii) extruding said dope through at least one orifice into a water-containing bath to form an elongate extrudate;
- (iii) producing said cellulosic regenerated elongate member by respectively either:
- (a) dissolving said solvent out of said elongate extrudate into said bath, or
- (b) regenerating said cellulose compound to form cellulose;
- (iv) dyeing said cellulosic regenerated elongate member with at least one planar molecular cationic direct dye;
- and
- (v) drying said cellulosic regenerated elongate member for the first time, said dyed cellulosic regenerated elongate member having a backstaining resistance of at least 4 measured by the ISO 3 wash test.
A dyed cellulosic regenerated elongate member having a backstaining resistance of at least 4 measured by the ISO 3 wash test and having been dyed in the never-dried condition with a planar molecular cationic direct dye.
Dependencies are inferred from the claim text.