TABLE OF CONTENTS Mineral fillers are supposed to reduce cost but, apart from calcium carbonate and a few other cheap materials, they often fail to deliver on cost because of their high density and the expense involved in incorporating them. Increasingly, recognition is being given to their positive role in controlling the physical, mechanical, dimensional and thermal properties of plastics. Thus plastics products can have increased or lowered density, higher modulus, better magnetic or dielectric properties, rapid heat dissipation, or whatever property is required, usually at the cost of translucency. The same polymer can thus be enabled to fulfil a number of different roles.
At a time when every effort is being made to increase productivity and reduce cycle times, filled plastics can increase throughput rates by virtue of their faster cooling rates. Fillers that do not slow down processing in other ways by producing excessively high viscosity mixes or introducing dispersion difficulties are preferred.
Demand for mineral fillers arises chiefly from the desire for cheap thermoplastics to be given better resistance to distortion under load, especially at elevated temperatures. This need is particularly great in automotive applications. The stiffening effect of the filler also allows thinner sections, using fine particle sizes.
The applications of mineral filled plastics include wire and cable, construction applications (including flooring), packaging, furniture, automotive components, domestic appliances and syntactic foam. Vehicles have always been an important outlet, determining the priorities in research and development, so scratch resistance and other aesthetic surface qualities...
