The spherical shape is one of the unique features that differentiates these products from other non-soluble additives. A sphere has the lowest surface area of any shape and, because of this, hollow glass microspheres have very low resin demand. Hollow glass microspheres roll past one another like ball bearings, with no rough surfaces or branches to entangle. At common loadings, there is only a minimal impact on viscosity when they are added to a liquid. Formulators can use hollow glass microspheres to increase the solid content of a coating while maintaining the proper application and flow characteristics. Higher solids can reduce volatile organic compounds (VOCs), shrinkage and drying time.
The large volume that hollow glass microspheres displace for a given weight is an important attribute in their use. Because hollow spheres will lower the density of materials they are added to, a gallon of coating will weigh less than the same product made without spheres. Lower-density coatings are cheaper to ship and easier to carry up a ladder. A low-density coating will atomize better, give less spatter when rolling, and sag less once applied. And since a small weight-addition of hollow glass microspheres increases the batch volume significantly, formulation cost can be reduced.
Since hollow glass microspheres are closed-cell, gas-filled particles, they are extremely good insulators. This characteristic is imparted to materials that contain hollow glass microspheres. Thermal and acoustic insulation properties of coatings or substrates can be improved by the addition of hollow glass microspheres. Makers of roof coatings, fire-retardant materials and sensitive acoustic equipment currently use this property.
This article comes from pcimag edit released