Production of monodisperse, polymeric microspheres
AssigneeCalifornia Institute of Technology
InventorsAlan Rembaum, Won-Kyu Rhim, Michael T. Hyson, Manchium Chang
Life of this patent
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Abstract
Very small, individual polymeric microspheres with very precise size and a wide variation in monomer type and properties are produced by deploying a precisely formed liquid monomer droplet, suitably an acrylic compound such as hydroxyethyl methacrylate into a containerless environment. The droplet which assumes a spheroid shape is subjected to polymerizing radiation such as ultraviolet or gamma radiation as it travels through the environment. Polymeric microspheres having precise diameters varying no more than plus or minus 5 percent from an average size are recovered. Many types of fillers including magnetic fillers may be dispersed in the liquid droplet.
Claims14
A method of forming uniformly sized, small, spherical, polymeric particles having a diameter from 100 Angstroms to 100 microns varying no more than plus or minus 5 percent from the average diameter without use of a catalyst comprising repeating the steps of:
- deploying a spheroidal droplet consisting essentially of a radiation polymerizable, unsaturated liquid monomer and absent catalyst or surfactant into a zone consisting of inert gas;
- levitating the droplet while in the zone;
- applying polymerization inducing radiation to the spherical droplet while in the zone and polymerizing the droplet throughout its volume to form a solid spherical particle;
- and
- recovering the solid particle.
A method of forming uniformly-sized, spherical polymeric particles comprising repeating the steps of:
- deploying a spheroidal droplet consisting essentially of radiation-polymerizable, unsaturated liquid monomer into a zone containing inert gas;
- levitating the droplet while in the zone;
- solidifying the droplet into a solid, spheroid droplet while in the zone by lowering the temperature of the liquid droplet below its melting point;
- and
- then polymerizing the solid droplet by applying polymerizing inducing radiation to the solid droplet to form a polymerized solid particle.
Dependencies are inferred from the claim text.