WATER-BASED DISPERSION OF pH-RESPONSIVE CHARGE VARIABLE POLYMER PARTICLE AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a water-based dispersion of pH-responsive charge variable polymer particles which is free from coagulation even at an isoelectric point.;SOLUTION: A method for producing the water-based dispersion of pH-responsive charge variable polymer particles is provided. The method includes a process of preparing a water-based dispersion by carrying out an emulsion polymerization of a polymerizable mixture comprising 100 pts.wt. polymerizable vinyl monomer with 5-40 pts.wt. specific water soluble polymerizable monomer polymerizable with the polymerizable vinyl monomer in an aqueous medium in the presence of a nonionic surfactant and a water soluble azo polymerization initiator. The nonionic surfactant has 16-18.5 HLB value, and is used in an amount of 5 pts.wt. and ≤15 pts.wt. based on 100 pts.wt. of the polymerizable monomer mixture. The polymer particles in the water-based dispersion have 0.01-0.1 μm average particle size (an average value of average particle sizes, when pH of the water-based dispersion is 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12).;COPYRIGHT: (C)2008,JPO&INPIT