ENCAPSULATED ACTIVATOR AND ITS USE TO TRIGGER A GELLING SYSTEM BY PHYSICAL MEANS

摘要

The instant invention relates to a process allowing the encapsulation of a polymerization accelerator, said process comprising the steps of: a) providing an reverse emulsion containing, in an oil phase, a water solution/dispersion containing the polymerisation activator, the oil phase including a heat curable mixture of an isocyanate and a polyalkyldiene hydroxylated or polyol, b) pouring the reverse emulsion in a water phase to make a multiple emulsion water/oil/water, containing drops of activators as the internal water phase, and then, c) heating the multiple emulsion obtained in step b) at a temperature of between 50 and 95°C, in order to cure the polyisocyanate in polyurethane and obtain drops of activator enclosed in shells of polyurethane dispersed in water. The invention also relates to aqueous gelling systems comprising the encapsulated polymerization accelerator with water soluble or dispersable monomers and a polymerization initiator dispersed in said monomers, useful i.a. for sealing subterranean environments or consolidation of a soil or sealing of a subterranean structure.