| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for producing a syrup that achieves improvement in both workability during the pouring of a syrup and the defoaming and productivity during the polymerization of a methacrylic resin plate by controlling the mass average molecular weight of the polymer contained in the syrup to a lower molecular weight without using a molecular weight regulator, and increasing the concentration of the polymer. Ž<P>SOLUTION: The method for producing a methacrylic syrup is effected by using as a raw material monomer, methyl methacrylate alone or a methyl methacrylate monomer mixture comprising methyl methacrylate and at least one unsaturated vinyl compound copolymerizable with methyl methacrylate. The method comprises adjusting the temperature of the raw material monomer contained in a reaction container to 60-130°C and then adding a radical polymerization initiator having a 10-hour half-life temperature of 120°C or lower in an amount of 0.01-1.0 pt.mass based on 100 pts.mass raw material monomer to adjust the peak temperature of polymerization to 140-170°C to produce a syrup such that the syrup has a polymer content of 20-55 mass%; the polymer has a mass average molecular weight of 40,000-90,000; and the syrup has a viscosity at 20°C of 30 Pa s or less. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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