摘要 |
<p>A process is disclosed for performing encapsulation, en masse, by an in situ polymerization reaction to yield capsule wall material. The polymerization comprises a reaction between melamine and formaldehyde and/or polycondensation of monomeric methylol melamine or etherified methylol melamine, or a low molecular weight polymer thereof, in an aqueous vehicle and the reaction is conducted in the presence of negatively-charged, carboxyl-substituted, linear aliphatic hydrocarbon polyelectrolyte material dissolved in the vehicle. Liquid-liquid phase separation is accomplished and maintained by increase in the molecular weight of the resulting condensation polymer without further dilution of the manufacturing vehicle. The negatively-charged polyelectrolyte material is required and has an apparent effect of controlling or modifying the polymerization reaction. The disclosed encapsulation process permits manufacture of micro-capsules in concentrations of capsule to capsule manufacturing vehicle higher than previously possible.</p> |