EP0462388A2 — Coated particles, hollow particles, and process for manufacturing the same

USPTO Abstract

Spherical particles comprising a core of a polymer and a metal compound covering the polymer core (polymer-metal compound coated particles), spherical particles comprising a core of carbon and a metal compound covering the carbon core (carbon-metal compound coated particles), and spherical hollow particles of a metal compound are disclosed. The spherical polymer-metal compound coated particles are prepared by homogeneously dispersing particles of a polymeric compound in an aqueous solution of a hydrolyzable metal salt to form a uniform layer of a metal compound on the surfaces of particles of the polymeric compound. The carbon-metal compound coated particles are prepared by heating the polymer-metal compound coated particles at a temperature of 150 °C or higher under an inert gas atmosphere to decompose the polymeric compound of the core into carbon. These particles have a specified outer diameter and a specified ratio of the core diameter to the outer diameter and are useful as standard particles, carrier particles used for diagnostic purposes, lubrication materials, electro-optical, electronic materials, and magnetic materials.