Incompatibility colourants

Impart a bright and intense colour to a substrate by a process which at least temporarily destroys any crystal structure of the colouring substances. Dyes are transparent and easy to disperse and process. Dyes are incompatible with polyolefins, having a tendency to bleed and plate out. Due to the solubility and... 

Acetoxy sealants are widely being used in a large number of applications in the construction industry. Where they are incompatible with specific substrates, they can be replaced by neutral cure systems. The alkoxy and oxime cure systems are available in either transparent (silica-filled composition only), or non-transparent/solid colour (silica-and/or chalk-filled composition containing appropriate pigment) versions. Their chemical neutrality enables these systems to offer a wide range of adhesive-bonding capabilities to... 

The world of gemstones and the world of reactor management, operation and utilization are culturally very different. The market for the stones is whimsical and difficult to assess. It is dependent on the size and the colour of stones currently in vogue. This often makes the behaviour of the gem trader also appear to be whimsical. In addition, the operating schedule for the research reactor and the time required for the irradiation and processing of stones is often incompatible with the needs of the trader. 

Fluorides,—These have been somewhat popular during recent years for the disinfection of breweries, etc., and also used to some extent as food preservatives. Of course only neutral fluorides are available for use in soap, acid fluorides and soap being obviously incompatible. In the authors experience, however, sodium fluoride appears to have little value as a germicide when added to soap, such soaps being found to rapidly become rancid and change colour. 

Cement/primer (CP) failures are characterised by the appearance of the primer on the bonded surface. Usually the adhesive and primer are different colours to allow for easier identification of both layers. CP failure is usually caused by contamination of the primer surface before application of adhesive, migration of plasticiser from the rubber into the adhesive/primer interface, insufficient drying of the primer film before application of the adhesive or by incompatibility between primer and adhesive. 

Dyes are exposed in the full depth of the coloured polymer, so especially stable materials are needed. Unfortunately, there are few dyes that approach pigments in light-fasmess (Table 14.2). Finely ground pigments may be used to achieve coloration with some loss of transparency. Problems of incompatibility are greater with dyes than with pigments. For a critical use, preliminary tests of compatibility and fasmess should be made. 

Some of these early materials found acceptabiUty, but often had to be discarded when it was found that they were incompatible with the rubber or caused staining of fight-coloured compounds or migration stains to other materials coming into contact with the vulcanized rubber component containing them. 

Note If using master batches for colouring, make sure the substrate is compatible with the plastic to be coloured. The effect of the use of an incompatible masterbatch is shown in Figure 9.9. 

Left Colour streaks due to an incompatible masterbatch Right Orientation of metal-effect pigments caused by the flow... 

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