| 摘要 |
PURPOSE:To obtain a good microcapsule preventing leakage and exudation of a core substance, by performing encapsulation by using an acidic aqueous solution prepared by adding an org. acid to a high concn. aqueous solution of a styrene/ maleic anhydride copolymer as an emulsifier. CONSTITUTION:After an aqueous solution containing 10wt% or more of styrene/ maleic anhydride copolymer with an average M.W of 10,000 or more, a pH of 7 or more and viscosity at 25 deg.C of 5,000cps or less is diluted if necessary, an org. acid such as oxalic acid is added to the diluted solution to adjust the pH thereof to 6 or less. A hydrophobic substance is dispersed or emulsified in this acidic aqueous copolymer solution so as to form discontinuous minute particles. Subsequently, a melamine-formalin precondensate is added to the resulting solution and reacted under an acidic heating condition to form a wall membrane around each minute particle. By this method, a microcapsule containing the hydrophobic substance as a core substance is obtained. This capsule is perfect in its membrane and suitable for preserving agricultural chemicals. |
