Mineral pigments filler content

The role of mineral fillers in plastic compounds is changing. In the past they were used to reduce costs by replacing polymer content by a less expensive material. Now they have a more important role to play since their use can modify processing characteristics or the properties of the finished part. Other uses include their ability to reduce the content of more expensive additives, notably pigments, flame retardants and impact modifiers. Nanomaterials are coming to the fore as potential fillers along with the more traditional options of alumina trihydrate, barium sulfate, calcium carbonate, kaolin and talc. 

To be able to produce a suspension having a controlled solids content, often of more than 70w/w%, special dispersants are required. Without such dispersants, a mixture containing a mineral, such as calcium carbonate, with only 30w/w% water is no longer flowable. Pigment and filler producers have developed highly active polymer systems, especially for the use of mineral slurries in the paper industry, which allow such concentrations to be achieved without destroying the complex chemistry of a paper machine. 

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