초록 ▼

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

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 polyelectrolyte material and certain salts, both dissolved in the vehicle. The disclosed encapsulation process permits the manufacture of microcapsules with more impermeable walls and/or lower capsule batch viscosities.

대표청구항 ▼

A process for manufacturing minute capsules, en masse, in an aqueous manufacturing vehicle, comprising: establishing an agitating aqueous system comprising (A) melamine and formaldehyde; (B) monomeric methylol melamine or a low molecular weight polymer thereof; or (C) monomeric methylated methylol m

A process for manufacturing minute capsules, en masse, in an aqueous manufacturing vehicle, comprising: establishing an agitating aqueous system comprising (A) melamine and formaldehyde; (B) monomeric methylol melamine or a low molecular weight polymer thereof; or (C) monomeric methylated methylol melamine or a low molecular weight polymer thereof as a starting material or mixtures of any of said starting materials, about 0.4 to about 15 percent by weight, based on the weight of aqueous manufacturing vehicle, of a system modifier material selected from the group consisting of poly(ethylene-co-maleic anhydride), poly(methyl vinyl ether-co-maleic anhydride), poly(acrylic acid), poly(propylene-co-maleic anhydride), poly(butadiene-co-maleic anhydride), poly(vinyl acetate-co-maleic anhydride) and poly(styrene-co-maleic anhydride), about 1 to about 10 percent by weight, based on the weight of aqueous manufacturing vehicle, of a salt selected from the group consisting of Periodic Group IA cations and tertiary and quaternary ammonium cations and chloride, sulfate, phosphate, nitrate, polyphosphate, citrate, maleate and fumarate anions, and particles of an intended capsule core material substantially insoluble in the system, in which agitating system the modifier is present prior to the addition of said particles, whereby said starting material polycondenses to form a condensation polymer resulting in (i) liquid-liquid phase separation of the resulting condensation polymer above a molecular weight to be soluble in the system; and (ii) continued polycondensation of the separated polymerization product to give solid capsule wall material individually surrounding particles of the dispersed intended capsule core wherein said salt is present in the aqueous manufacturing vehicle prior to the polycondensation, whereby increased capsule wall integrity and reduced capsule slurry viscosity are obtained.