Nano - from nature!: Neuburg Siliceous Earth - a fine functional filler with a special structure

摘要

The extraction of natural mineral fillers has been pursued for more than two hundred years. During this period, the requirements placed on such fillers, and consequently the products themselves, have changed considerably. In particular with respect to product consistency, purity and functional properties, functional fillers have to respond to ever higher and more stringent demands. In connection with innovations in paints and coatings, today there are frequent references to "nanotechnology". In this context, quite frequently products and materials are proposed which, in view of a missing generally accepted definition, do not really deserve this designation. In theory, any ultrafine natural mineral filler with a mean particle size of less than 1 micron could be called a nano filler, which would mean 'nano from nature'. Neuburg Siliceous Earth, with primary particles below 500 nm, would easily fit into this category. Although uniform rules do not exist yet, it can be readily concluded from scientific publications that only products with average particle size distributions less than 100 nm should be considered as nano materials. The majority of natural mineral fillers do not meet this more stringent requirement.