It was investigated how the addition of a mixture of two water-soluble polymeric species affe-cted the state of encapsulation of pigments by soap-free emulsion polymerization. The pigments examined were disazo-yellow (Index number, PY17), phthalocyanine blue (Index number, PB 15 : 3), and carbon black (# 15), which had been predispersed in the aqueous solution of a sur-factant before the polymerization. The monomer used for the encapsulation was methyl metha-crylate. The surfactants added were hydroxy-propyl methyl cellulose (HPMC) and poly (vinyl alcohol) (PVA). In this experiment, the sate of encapsulation was mainly examined by the addition of PVA and HPMC with different degree of polymerization. It was found that the pigments were encapsulated better by the addition of the mixture of PVA and HPMC rather than the individual surfactants.
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