While high-quality hollow glass microspheres tend to be more expensive, some lower-cost hollow glass microspheres have limitations such as poor shape and uniformity or lack of consistency between batches, wide particle-size distribution, the presence of dust and debris, poor roundness and sphericity. It is not uncommon for low-cost low-quality hollow glass microspheres to contain a significant amount of crushed, oblong and non-spherical particles, which could negatively impact the texture, appearance and feel of finished products and/or performance in an application.
It is important for formulators to select a supplier that manufactures particles in a controlled environment and thoroughly screens them to prevent any dust, debris and nonspherical microparticles entering the system. Depending upon the requirements for a formulation and properties of hollow glass microspheres, specifications for the maximum amount of unacceptable particles must be determined and communicated to the supplier.
For example, with luxury cosmetic applications, most formulators will look for high-quality identical polymer hollow glass microspheres with excellent uniformity. For large-volume low-density concrete-filler applications sold by the truckload, price may be a more critical factor than particle size and color uniformity.