Manufacturing method and building a bridge particle null of the melamine resin building a bridge particle of the hollow condition which possesses uniform particle

摘要

PURPOSE:To obtain the title particle useful as an organic filler by introducing a solvent or substance which can dissolve or swell the melamine resin condensate to the reaction system after the condensation reaction solution becomes turbid because of the deposition of particles and continuing the reaction. CONSTITUTION:A water-soluble precondensate among melamine, form-aldehyde and methanol is condensed in the presence of a curing catalyst such as an organic acid in an aqueous medium containing a water-soluble carboxylic polymer or a water-soluble copolymer of an ethylenically unsaturated carboxylic monomer; after the reaction solution becomes turbid because of the deposition of particles, a solvent or substance which can dissolve or swell the melamine resin condensate which forms the particles is introduced into the system or the reaction solution is diluted with a reaction solvent after this introduction; and the reaction is continued to completion. In this way, a hollow crosslinked melamine resin particle having a uniform particle diameter can be produced. The particle has a uniform particle diameter, neither dissolves nor swells in organic solvents such as an alcohol such as methanol, xylenol and acetone, and does not fuse even when heated to 200 deg.C, so that it can be used as a lightweight inexpensive organic filler.