LABORATORY HEAT STABILITY:   Tested on a screw injection moulding machine in polypropylene at 200, 220, 240, 260 and 280 centigrade without and with a 5 minute interruption of the injection cycle. The material was first pigment with special percentage of pigment and titanium dioxide rutile and compounded in a single extrusion. The symbols preceding the temperatures signify: + the pigment withstands the given temperature in a normal injection cycle without a change of shade. + + the pigment withstands the given temperature without a change of shade even with a 5 minute interruption and subsequent further processing. When the pigment preparation mono masterbatches are used in different percentages or in combination amongst themselves or with others, the value of technical data could change considerably.