COLOUR CHANGE: FROM YELLOW PP TO NATURAL PP

In this case study Michael Knabe, our Distributor for Germany tells us how he achieved a colour change from a masterbatch of egg yolk yellow PP to natural PP and removed Carbon on a 280T Engel machine using Barrel Blitz Universal (BBU). He knew this trial could reveal some interesting results as the machine’s screw hadn’t been pulled for about a year. The customer’s biggest issue was staining from coloured material. Pigmented plate-out on the screw had degraded to carbon and had cracked allowing coloured material to get stuck between these cracks. Over time both Carbon and coloured material had become engrained onto parts of the machine. In the image below you can see how the ‘egg yolk’ yellow PP (top left, at 9-12 o’clock) and the dirty yellow material (on the brown cardboard, 1 o’clock).