PURPOSE: To obtain titled latex which is stable and uniform in particle size, by copolymerizing styrene with a specified (meth)acrylic acid derivative and a specified styrenesulfonate in the presence of submicroscopic silicic acid anhydride and a water-soluble radical polymerization initiator.
CONSTITUTION: Titled latex is obtained by copolymerizing, in water, styrene with about 0.1W70wt%, based on styrene, compound of the formula, wherein R1 and R2 are H or CH3, x, y and z are each 0W100 and 1≤x+y+z≤100, and about 0.0001W10wt%, based on styrene, styrenesulfonate in the presence of about 0.01W 10wt%, based on styrene, submicroscopic silicic acid anhydride particles, particle size about 5W50mμ, by use of a water-soluble radical polymerization initiator. The obtained latex has an average particle size of about 0.05W2μ and a dispersion of the particle size in terms of a variation coefficient of below 0.05, and can be suitably used as a serodiagnostic agent.
OBANA SATOSHI
KUGE MICHIO
