Uniform spherical-shaped microspheres have lower surface area then irregular fillers and extender pigments, which means a lower resin demand. Another benefit to the spherical shape is the ability to roll past one another, hence there is minimal impact on viscosity when they are added to a liquid. As coatings are manufactured on weight basis and sold on volume basis, microspheres are used to increase the solid content of a coating, maintaining application and flow properties. Higher-volume solids reduce VOCs, shrinkage and drying time.
Since hollow glass microspheres lower the density of materials, they are added to coatings. If added in coatings, it will atomize better while spraying and it will give less spatter while rolling also sag less once applied.
One of the most important applications microspheres have been developed for is the Space Shuttle program. When the space shuttle re-enters the earth’s atmosphere, incredible heat is generated due to increasing air friction. In order to prevent the space shuttle from burning up during re-entry, NASA scientists developed a superior insulating material using Ceramic technology. This technology can now be applied to roofs and sidewalls of buildings, piping, ducts, tanks, various storage devices, refrigerated containers, cold rooms, etc. in order to insulate them from the radiant heat of the sun and the atmosphere by using hollow ceramic spheres.
Stagnant air is a bad conductor of heat because heat is transferred by convection currents. Stagnant air inside hollow glass microspheres acts as an insulator for heat and hence can be used as heat insulating material in coatings. This characteristic of hollow glass microspheres allows improved thermal and acoustic insulation properties of coatings or composites. Currently, markets taking advantage of this property include fire retardant materials, sensitive acoustic equipment, and roof coatings.
