Development of a hollow microcapsule preparation method under neutral pH and low temperature using melamine–formaldehyde prepolymer

The preparation of hollow microcapsules using melamine–formaldehyde (MF) prepolymer was investigated. Chlorobenzene was used as the core material, and large emulsion droplets were prepared by the Shirasu-porous-glass (SPG) membrane emulsification method. The effects of polymerization conditions were evaluated using MF prepolymer as the capsule wall material. Good capsule formation was possible even under mild conditions near neutral pH and at room temperature. Measurements of the bulk density and core retention rate of the capsules confirmed that a certain amount of core material could be removed. This technology is considered to be highly cost-effective and industrially useful.