Preparation of Melamine-Formaldehyde Resin Microcapsules Containing Fragrant Oil by Condensation Polymerization

Microcapsules can prevent the wrapped core materials from evaporating, extend the releasing time and stabilize the core materials during storage. Since fragrant oil has high evaporation property, it is very suitable to be treated by microencapsulation for further applications. In this study, we used melamine and formaldehyde as the shell materials with fragrant oil as the core materials to prepare microcapsules by condensation polymerization method. The purpose of this research is to synthesize the microcapsules containing fragrant oil with narrow size distribution and high capacity. Six factors considered in our experiments include temperature, stirring rate, the mass ratio of fragrant oil, the kinds of emulsifiers, and the mass ratio of emulsifier. It was found that, the higher the stirring rate or the lower the mass ratio of fragrant oil, the smaller the average diameter of microcapsules. In addition, by employing the software of Design-Expert 5 to analyze the experimental data, it was concluded that the degree of the effect of the factors on the particle size of microcapsules follows the order of the mass ratio of emulsifier > the mass ratio of fragrant oil >> stirring rate > temperature, and that on the encapsulating efficiency of microcapsules follows the order of the mass ratio of emulsifier > the mass ratio of fragrant oil >>temperature≒stirring rate.