Product testing pigment dispersion

Even more sensitive than these staining tests for detecting grease and oil contamination is an imprint on thermoplastic films (see Section 8.4.6). During production of the imprint, hydrophobic deposits diffuse into the film and can usually be easily recognized by the local cloudiness they cause. The natural waxes of cotton do not interfere here because they are evenly distributed. Spots caused by pigments or disperse dyes are also transferred onto the film imprints and are then easier to investigate microscopically. ... 

Process NMR is used for chemicals (free/bound moisture, viscosity, activity, loading efficiency in powders, catalysts, liquids, detergents, pigments) and polymers (density, crystallinity, rubber and copolymer content, dispersion of fillers, melt properties, finish content, extent of cure and cross-linking, content of solubles, plasticisers, moisture, etc.). Process NMR is fully operational in the polymer industry, both as on-line units [202] which provide virtually continuous process feedback control as well as off-line and laboratory units for checks of the various processes [198]. The use of NMR for advanced process control has reduced the need for frequent wet tests, has reduced off-spec materials and has improved product transition times. 

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