| Summary: | Polypropylene (PP) offers many advantages to the textile processor in terms of its durability and end use properties. However, a major technical flaw of PP is its inability to be dyed due to its relative lack of dye adsorption sites and high crystallinity. Therefore it is primarily mass pigmented, with pigment incorporated into the polymer melt prior to extrusion. While this approach offers a successful commercial route it does lack process flexibility. Some research has focused on modifying the polymer structure by incorporating dyeable copolymers or chemically degrading the base polymer by aqueous treatments to create polar groups for dye adsorption. However, both of these approaches have had little success due to processing difficulties, excessive deterioration of polymer properties and cost. In this study the primary thrust of the research has been to evaluate the use of dry gaseous fluorine treatments to modify the PP fibre and create dyeability and better colour fastness. XPS and FTIR indicate reaction between fluorine and the polypropylene fibre and the introduction of carboxyl groups and fluorine into the polymer. The introduction of these carboxyl groups and strongly electronegative negative fluorine leads to the fibre's enhanced basic dyeability. SEM analysis showed the impact of fluorine exposure on fibre surface morphology is relatively small. The effectiveness of pre-treatments on pigment dyeing and printing has also been evaluated. Colour fastness was significantly improved by a gaseous fluorine pretreatment of the textile substrate. The Helizarin Binder UDR pigment dyed system showed better performance in terms of colour fastness than other commercial binder systems evaluated. Optimisation of the binder to pigment ratio has been achieved in order to obtain good colour fastness. The dycability of moulded polyacetal zips was also examined in order to potentially replace the current mass pigmentation process. Fluorine pre-treatments showed no benefits in the overall colouration. properties in terms of long liquor dyeability or pigment dyeing. Of the disperse dyes evaluated the "high performance" SF and XF classes had the best colour fastness, in particular Dispersol Red CBN-SF, Dispersol Blue XF and Dispersol Flavine XF. A range of after-treatments were evaluated and a "reduction cleae, significantly improved the colour fastness. The polyacetal/polyester zip construction offered significant colouration difficulties due to the inherent problem of achieving a uniform, compatible, "soliX' dye shade. Although some success was achieved, commercial utilisation is less likely due to increasing process complexity.
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