| 摘要 |
PURPOSE:To obtain granulated acrylic polymer of good water-solubility, by irradiating an aqueous solution of a cationic vinyl monomer with ultraviolt rays in the presence of a nonionic surfactant and a photopolymerization initiator in an atmosphere of an oxygen content of a specified concentration or below and thereby polymerizing the monomer. CONSTITUTION:An acrylic polymer is obtained by polymerizing an aqueous solution of a cationic vinyl monomer or its mixture with other water-soluble vinyl monomers in the following manner. Said aqueous solution is fed to a movable belt and irradiated with ultraviolet rays under conditions including a total monomer concentration in said aqueous monomer solution of 50-80wt%, a pH of 4-7, an amount of a nonionic surfactant of 0.001-1wt% based on monomer, a dissolved oxygen in the monomer solution, of 1mg/1 or below, an amount of a photopolymerization initiator of 0.03wt% or below based on the monomer and an oxygen content in the vapor phase of 1vol% or below. The formed rubber-like layer polymer sheet is continuously withdrawn from the movable belt, crushed, finely pulverized by a vertical cutter and dried with hot air.
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