Microscopic glass spheres are used in many applications, including as an abrasion-deterring element in grating components in mechanical engineering; as an adjusting aid and distancing element of electricity conducting single components in microelectronic mechanics; and as a material for artistic surface design.
A New Adhesive System
A breakthrough in the area of large format graphic films is the Controltac adhesive system. In this, approximately 50 µm strong films are equipped with the adhesives. In addition to the adhesive, millions of small microscopic (40 up to 50 µm diameter) glass spheres, in precise, regular arrangement, are applied after micro-structuring the surface.
The small glass spheres cause a gliding effect between the area to be adhered and the adhesive, allowing precise alignment of the foil. When stronger pressure is applied, the spheres become embedded in the adhesive layer, which is permanently fixed to the base. This technology enables large formatting foils to be adhered.
Another new application is the use of a composite material comprised of metal and glass spheres. The new material shines like solid metal and feels the same, although it is extremely lightweight. In this system, the metal is poured inside hollow glass spheres measuring 60 µm.
As the spheres are uniformly distributed, they yield an even surface, which is smooth like metal. With an uneven distribution of the glass spheres, the material looks marbled with veins.
Even though the material is extremely porous, it has a smooth metal-like appearance and is very light. In this method, the density of aluminum is reduced from 2.7 g/cc to 1.2 g/cc, and for zinc from 7 g/cc to 3.1 g/cc, a reduction of more than 50%.
The figure below shows the particle size distribution of hollow glass spheres achieved with the ANALYSETTE 22 (maximum measuring range: 0.01 – 3800 µm). The measurement was performed using the dry dispersion unit with an adjusted pressure at the Venturi injectors.
The measuring range covered was from 0.85 up to approximately 116 µm. The Mie-theory was applied during the evaluation of the measured data, because for samples with smaller particle diameters and with small refractive indices, an already significant deviation of the calculation, according to Fraunhofer, approximation is noticed.
A distribution curve from the Fraunhofer approximation was also drawn into the diagram for comparison purposes.
This information has been sourced, reviewed and adapted from materials provided by FRITSCH GMBH - Milling and Sizing.
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