Patent ID: 6531222
Filing Date: 2003-03-11
Classification: C03C,Y10T

Abstract:
Hollow glass microspheres which have an average particle size of at most 15 &mgr;m (based on volume), a maximum particle size of at most 45 &mgr;m, a particle density of at most 0.5 g/cm3, a grain size gradient of at most 2.0 as represented by the following formula, and a B2O3 content contained in the glass of from 9.0 to 20.0 mass %:grain size gradient=(d10âˆ’d90)/d50 wherein d10, d50 and d90 are particle sizes with which values of volume-based oversize particle cumulative distribution become 10%, 50% and 90%, respectively, as measured by a laser scattering type grain size measuring apparatus.