| 摘要 |
PURPOSE:To produce the title crosslinked resin suitable as a paper filler continuously on an industrial scale in high yields, by grinding an aqueous slurry of a crosslinked urea/fromaldehyde resin obtained by a specified production process with an ultrasonic dispersion grinder. CONSTITUTION:An aqueous slurry of a crosslinked urea/formaldehyde resin obtained by reacting a urea/formaldehyde precondensate in the presence of an acid catalyst is ground with an ultrasonic dispersion grinder, for example, a dispersion grinder having at least two sets of generators each consisting of a comb-toothed concentric ring, a rotor and a stator. A shearing force and ultrasonic waves are generated by the mechanical action resulting from the motion of the rotor 2 and the stator 1, and the generated ultrasonic waves cause cavitation, so that the resin is ground by their synerigistic action to give the title crosslinked resin of an average particle diameter of 1-30mum, especially, 1-10mum. Because the ultrasonic dispersion grinder has a pumping action, it can be operated continuously and enables production on an industrial scale.
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