Microcapsules in polypropylene fibres

At the Textile Department in Ljubljana trials of spinning polypropylene fibres with microcapsules on a laboratory spin-draw device by firm Extrusion Systems Limited were performed. Although it seems quite a simple task, spinning polypropylene fibres with microcapsules is not easy and we also come to some problems such as: mcrocapsules tend to agglomerate and as a consequence the spin pack was plugged, large particles produce weak points in filament, which lead to its break, the distribution of the microcapsules in the fibre was not homogeneous. Masterbatch which is also used at the dyeing and printing of the polypropylene fibres and ensure better distribution of pigment, was used, when microcapsules were incorporated into the polypropylene fibres. Masterbatch consists of the polypropylene polymer, pigments and surface-active agent. Different disperse agents were used to prevent or reduce agglomeration. Masterbatch and microcapsules were added to the polymer in the feeding zone of the extruder prior melting of the polymer. Melting temperature, spinning process velocity, velocity of the godet and draw wind were adapted during the spinning process.