Conventional aqueous dispersions of a thermoplastic resin have been produced either by a process where a polymerisable monomer which is the resin raw material is polymerised by emulsion polymerisation in an aqueous medium in the presence of a dispersing agent, or by a process where a molten thermoplastic resin and an aqueous medium, and optionally a dispersing agent, are mixed by applying shearing force. The former process is associated with the disadvantage of the limited number of the polymerisable monomers that can be used, and hence, the variety of the aqueous dispersions of the thermoplastic resin that can be produced, is limited. The former process also suffers from complicated control of the polymerisation reaction as well as intricate equipment. On the other hand, the latter process is applicable to a wide variety of resins in relatively simple equipment.
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