Preparation of Pressure Sensitive Melamine-formaldehyde Resin Microcapsules by in-situ Polymerization

The pressure sensitive melamine-formaldehyde resin microcapsules were prepared by using in-situ polymerization method with leuco dye crystal violet lactone as core and the melamine-formaldehyde resin as cyst wall.The three-step method was used to adjust the acidity,and blue-stain of the dispersion system was effectively eliminated in the process.The optimum emulsification conditions were as follows:dosage of emulsifier was 50wt%,emulsification was carried out by dispersing for 20 min with 2000 r/min agitation,the suitable proportion of core material and wall material was 1:2,the pH of curing phase was 4.0.The results showed that the prepared microcapsules were single core and single wall,outer surface was gloss and compact,average partical size was small,particle size distribution was concentrated at 0.5～5.0 μm,the core material was fully coated.