The present invention teaches an improved process for preparing a
population of microcapsules having a substantially uniform size
distribution, especially useful for manufacture of carbonless paper. The
improved process teaches use of membrane material having a pre-selected
pore size in the capsule manufacture process. A core material is provided
along with a receiving solution for receiving the core material. The
receiving solution is a nonsolvent for the core material. The core
material is passed under pressure through the membrane into a moving or
turbulent receiving solution forming uniform droplets of core material
dispersed in the receiving solution. Wall-forming material is added to
the receiving solution for coating the core material droplets. The
coating on the droplets is polymerized forming microcapsules. This novel
process also lends itself to microcapsule formation in a continuous
process.