Methods for producing hollow microspheres made from dispersed particle compositions

DETAILED DESCRIPTION The present invention relates to hollow microspheres made from dispersed particle film forming compositions comprising dispersed particles, binder, film stabilizing agent, dispersing agent and continuous liquid phase.
The present invention particularly relates to hollow green microspheres made from dispersed particle film forming compositions comprising dispersed solid particles, a binder material, a film stabilizing agent, a dispersing agent for the solid particles and a continuous aqueous or non-aqueous liquid phase.
The present invention particularly relates to hollow green microspheres made from dispersed particle film forming compositions which hollow green microspheres are substantially spherical, have substantially uniform diameters and have substantially uniform wall thickness.
The hollow green microspheres are free of latent solid or liquid blowing gas materials, and the walls of the hollow green microspheres are substantially free of holes, relatively thinned wall portions or sections and bubbles.
The present invention particularly relates to rigid hollow porous microspheres which are substantially spherical, have substantially uniform diameters, and have substantially uniform wall thickness and the walls have uniform void content and void distribution and voids which are connected to each other and to the inner and outer microsphere wall surfaces.
The walls of the hollow porous microspheres are free of latent solid or liquid blowing gas materials, and are substantially free of relatively thinned wall portions or sections and bubbles.
The hollow green microspheres can be made from ceramic, glass, metal, metal glass and plastic particles, and mixtures thereof.
The present invention relates to a method and apparatus for using a coaxial blowing nozzle and a blowing gas to blow hollow microspheres from a dispersed particle film forming composition comprising feeding the blowing gas to an inner coaxial nozzle, feeding the dispersed particle film forming composition to an outer coaxial nozzle, forming spherically shaped hollow microspheres in the region of the orifice of the coaxial blowing nozzle and removing the hollow microspheres from the region of the orifice of the coaxial blowing nozzle