PROCEDIMIENTO PARA LA FABRICACION DE MICROCAPSULAS PARA PA- PEL SENSIBLE A LA PRESION

摘要

Pressure-sensitive recording papers cannot be prepared by using a fast-drying organic solvent as a dispersion medium for microcapsules containing a colourformer solution because conventional microcapsules do not possess satisfactory resistance to the solvent. This problem is overcome by microcapsule having walls prepared by polycondensing a water-soluble cationic urea resin and at least one prepolymer selected from melamine-formaldehyde, urea-formaldehyde and melamine-urea-formaldehyde prepolymers on the surface of dispersed droplets of a colour-former solution in the presence of an anionic surfactant. Complex-coacervation occurs between the water-soluble cationic urea resin and the anionic surfactant during poly-condensation. The microcapsules find use in pressure-sensitive recording.