Generally speaking, the word “hybrid” as applied to emulsion polymers means that the particles are composed of one material that is not normally produced via emulsion polymerization (EP) and another material that can be produced via EP. Thus, the resultant particles are composites.
One common example is a polyurethane (PU)/acrylic hybrid latex where the PU is first synthesized via condensation polymerization in the form of a colloidally stable aqueous dispersion, and then the acrylic polymer is formed via free radical polymerization in the presence of the PU dispersion.