AQUEOUS POLYMER DISPERSION, THICKENER FOR AQUEOUS SYSTEM, OIL-IN-WATER DISPERSION, AND PREPARATION OF AQUEOUS POLYMER DISPERSION

摘要

PROBLEM TO BE SOLVED: To obtain an aq. polymer dispersion which has a high mol.wt. and a high stability and is useful for a thickener and a binder by subjecting a mixture of ethylenically unsatd. free-radically polymerizable monomers to free radical polymn. in an aq. emulsion under specified conditions. ;SOLUTION: A mixture comprising free-radically polymerizable monomers having at least one kind of ethylenically unsatd. group is subjected to free radical polymn. in an aq. emulsion under such conditions that (A) the monomer mixture comprises 30-90 wt.% monomer having a water solubility of 5 wt.% or higher and 10-70 wt.% monomer having a water solubility lower than 5 wt.% at selected polymn. temp. and pressure; (B) the monomer mixture does not contain a surface-active monomer; and (C) the polymn. is conducted in a dispersion medium comprising water and an org. solvent having a water solubility of 10 wt.% or lower, pref. 6 wt.% or lower, at the selected polymn. temp. and pressure, the amt. of the org. solvent being adjusted so as to be not higher than twice as much as water but to be enough to form a solvent phase.;COPYRIGHT: (C)1996,JPO