초록 ▼

Hollow microspheres are made by a process which comprises forming a film of a dispersed particle film-forming composition (containing dispersed particles, a binder, a film stabilizing agent and a continuous liquid phase) across a coaxial blowing nozzle, applying a blowing gas at a positive pressure

Hollow microspheres are made by a process which comprises forming a film of a dispersed particle film-forming composition (containing dispersed particles, a binder, a film stabilizing agent and a continuous liquid phase) across a coaxial blowing nozzle, applying a blowing gas at a positive pressure on the inner surface of the dispersed particle composition film to blow the film and form, in the region of the coaxial blowing nozzle orifice, hollow dispersed particle microspheres having stable film walls, removing the hollow microspheres, treating them to bring dispersed particles into point to point contact and harden them to obtain hollow green microspheres, and subsequently subjecting them to a sufficiently high temperature for a sufficient period of time to remove the continuous liquid phase and to sinter the dispersed particles at their points of contact to form within the walls of said hollow microspheres interconnecting voids that are continuous from the outer wall surface to the inner wall surface of the hollow microspheres, and to obtain hollow porous microspheres having substantially uniform void content and substantially uniform distribution of the voids in their walls.

대표청구항 ▼

A method for making hollow green microspheres of 200 to 10,000 micron diameter and of 1 to 1000 microns wall thickness from a stable dispersion of a dispersed particle film forming composition, said composition comprising dispersed particles in a continuous liquid phase, said method comprising feedi

A method for making hollow green microspheres of 200 to 10,000 micron diameter and of 1 to 1000 microns wall thickness from a stable dispersion of a dispersed particle film forming composition, said composition comprising dispersed particles in a continuous liquid phase, said method comprising feeding said dispersed particle composition and a blowing gas to a coaxial blowing nozzle, said coaxial blowing nozzle having an inner coaxial nozzle for said blowing gas and an outer coaxial nozzle for said dispersed particle composition and a coaxial blowing nozzle orifice, feeding said blowing gas to said inner nozzle, feeding said dispersed particle composition to said outer nozzle to blow and form, in the region of said coaxial blowing nozzle orifice, hollow dispersed particle composition microspheres having stable film walls, removing said hollow microspheres from the region of said coaxial blowing nozzle orifice, surface tension forces acting on said hollow microspheres to cause said hollow microspheres to form a spherical shape, said dispersed particle composition forming the walls of said hollow microspheres and said dispersed particles being uniformly dispersed in said continuous liquid phase, treating said removed hollow microspheres to remove a portion of the continuous liquid phase to bring the dispersed particles into point to point contact and to harden them, said dispersed particles being of sufficient size and in a sufficient amount such that the dispersed particles in the walls of the hollow microspheres link up and form a relatively rigid lattice work of dispersed particles, and obtaining hollow green microspheres that have substantially uniform distribution of the dispersed particles in the continuous phase of the walls of the microspheres. Hollow green microspheres of substantially uniform diameter of 500 to 6000 microns and of substantially uniform wall thickness of 5 to 400 microns, the walls of said hollow microspheres comprise a dispersed particle composition comprising dispersed particles in a continuous phase, said dispersed particles being uniformly dispersed in said continuous phase and said dispersed particles being of sufficient size and in a sufficient amount such that the dispersed particles in the walls of the hollow microspheres are in point to point contact and are linked up and form a relatively rigid lattice work of the dispersed particles, said hollow green microspheres are free of latent solid or liquid blowing gas materials and the walls of said hollow microspheres are substantially free of relatively thinned wall portions, holes and bubbles.