反应详情

A hydrophobic dispersing medium colored by dissolving 1 part by weight of an oil-soluble dye oil blue in 150 parts by weight of paraffin-based hydrocarbon isoper (Exxon Corporation) was prepared. 5 parts by weight of titanium dioxide (Ti-PURE R104 manufactured by DuPont) subjected to hydrophobic treatment was added as electrophoretic particles to the hydrophobic dispersing medium and dispersed therein for 10 minutes by a sonicator to give a hydrophobic dispersion. Separately, an aqueous solution wherein 20 parts by weight of styrene-maleic anhydride resin were dissolved as water-soluble polymer in 1500 parts by weight of deionized water was prepared. The previously prepared hydrophobic dispersion was then added to this aqueous solution and emulsified and dispersed for 10 minutes at a circumferential speed of 5 m/s with Clearmix manufactured by MTECHNIQUE Co., Ltd. Separately, a mixture consisting of 150 parts by weight of 37% formalin, 50 parts by weight of melamine and 400 parts by weight of deionized water was adjusted under stirring to pH 9.0 with an aqueous solution of caustic soda and reacted at 60° C. for 20 minutes to give a transparent melamine/formaldehyde condensate. In a step of forming microcapsules, this reaction solution was added to the previously emulsified dispersion introduced into a reactor equipped with a Max Blend blade manufactured by Sumitomo Heavy Industries, Ltd. and then reacted at 50° C. for 3 hours in-situ under stirring conditions at a circumferential speed of 0.75 m/s. The particle diameter of the resulting microcapsules having electrophoretic particles encapsulated therein was 15 μm, and the coefficient of variation was 36%. The particle diameter was determined from the average diameter of 100 particles observed under an optical microscope.

1. customwas prepared
2. additionwas added as electrophoretic particles to the hydrophobic dispersing medium
3. additiondispersed
4. customfor 10 minutes by a sonicator to give a hydrophobic dispersion
5. customwas prepared
6. additionThe previously prepared hydrophobic dispersion was then added to this aqueous solution
7. additiondispersed for 10 minutes at a circumferential speed of 5 m/s with Clearmix
8. customreacted at 60° C. for 20 minutes