| 摘要 |
PURPOSE:To obtain a microcapsule for a pressure sensitive recording paper excellent in solvent resistance, by polycondensing a water soluble cationic urea resin, an anionic surfactant and a specific prepolymer in an aqueous dispersion of a color former solution. CONSTITUTION:An aqueous mixed solution, which contains a prepolymer selected from a group comprising a mixture of a melamine-formaldehyde prepolymer and a urea-formaldehyde prepolymer, melamine-urea-formaldehyde prepolymer and a mixture thereof, a water soluble cationic urea resin and an anionic surfactant, and a color former solution are emulsified and dispersed by using an apporiate means, for example, a stirring machine or ultrasonic waves in such a manner that the color former solution is formed into fine liquid proplets with a particle size of about 1-8mu. Subsequently, an acid catalyst is added to the resulting dispersion while this dispersion is gently stirred to react at pH of 2.5- 6.0 and at a reaction temp. of 15-60 deg.C for 2-15hr to obtain a microcapsule. |
