| 摘要 |
PURPOSE:To obtain a microcapsule of improved holding capacity of hydrophobic contents and resistance during handling by causing polycondensation reaction through using melamine, guanamine deriv. and formaldehyde in the presence of anionic polyelectrolyte. CONSTITUTION:Hydrophobic material such as dyes used for no carbon pressure- sensitive copying paper or the like is emulsified and dispersed in an aqueous soln. of anionic polyelectrolyte such as styrene-maleic acid anhydride copolymer. This emulsion is transferred to a reaction apparatus, where it is added with an aqueous precondensate soln. prepd. by dissolving melamine and the guanamine deriv. such as formguanamine expressed by the formula in an aqueous formaldehyde soln. and is stirred under heating, whereby the reaction for capsulation is caused. Thence, its pH is adjusted by adding an aqueous sodium hydroxide soln., whereby the emulsion of the microcapsule is obtained. If these microcapsules are used for no carbon pressure-sensitive copying paper, breakdown efficiency is considerably improved under low impression pressure and writing pressure. |
