摘要 |
A process for the preparation of composite particle dispersions is disclosed. The composite particles have a core particle 1 surrounded by a second material 2. Normally a core shell particle will be formed and the second material which forms the shell will be a polymer material. The composite particles are formed by mixing a dispersion of polymer particles with pre-formed core material particles. The polymer particles are stabilised relative to one another, and the core material particles are destabilised in the dispersion so that they are able to make contact with the surfaces of the polymer particles. The process takes place at a temperature above the operative glass transition temperature of the polymer, and in the process the polymer spreads over the surface of the core particle so that the core particle is encapsulated. The process will proceed, and composite particles will be formed, when the interfacial energies of the three interfaces (core/polymer: core/liquid: polymer/liquid) and the relative volumes of the core particles and polymer particles are related to one another in accordance with an equation which is set out in the specification. |