| 摘要 |
PURPOSE:To form a fine, uniform and dense coating by a method wherein, in a microcapsule of a hydrophobic liquid obtained by an interfacial polymerization method, a thio acid salt is added to an aqueous solution containing an emulsifier to control the reaction of a polyvalent isocyanate and water. CONSTITUTION:In a microcapsule obtained by emulsifying a hydrophobic liquid containing a polyvalent isocyanate dissolved therein (containing an electron-donating color developer for a carbonless reproducing paper, such as crystal violet) into an aqueous solution containing an emulsifier in a minute droplet form and, thereafter, forming a coating at an interface, as a control agent against the viscosity rise during an emulsifying procedure, a thio acid salt such as thiosulfuric acid salt or thiocyanic acid salt is added to an aqueous solution containing an emulsifier. Thus the viscosity rise during an emulsifying procedure can be prevented and the emulsification can be carried out over a long period of time at a room temp. Furthermore a diameter of a microcapsule can be controlled to a desired particle diameter and the coating having excellent characteristics of strength, heat resistance and solution resistance as compared with the one obtained by a conventional method can be formed. |
