Kinetics of dyeing process of blend polypropylene/polyester fibres with disperse dye

The dyeing of unmodified polypropylene (PP) fibres by the exhaustion method is characterized by a low affinity of dyes to the PP and by the low colourist parameters (a low colour fastness, a low washing and dry-cleaning fastness) in the dyed fibres. The preparation of polypropylene/polyester (PP/PES) blend of fibres is interesting from the point of dyeability in these fibres from dyebath. Polyester's additive in PP matrix is able to fix disperse dyes and increase the uptake of the dye from a bath. This paper presents the influence of two polyesters (polyethylene terephthalate – PET and polybutylene terephthalate – PBT) in the kinetics of dyeing of PP/PES blend fibres with disperse dye C.I. Disperse Blue 56. The dye uptake, dyeing rate constants, diffusion coefficients and activation energy of PP/PES blend fibres were defined.