PURPOSE: To efficiently obtain the subjective polymer having improved washability, color tone and heat resistance due to narrow molecular weight distribution and low content of low molecular weight substances, by using a caustic alkali and a phenolic compound as raw materials and carrying out polymerization thereof by two steps respectively under specified conditions.
CONSTITUTION: A caustic alkali and a phenolic compound (pref. bisphenol A, etc.) are initially introduced into the first reaction zone in such an amount as to be 0.9-1.8 equivalent ratio of respective hydroxide groups in the alkali and the phenolic compound and polymerized to prepare a polycarbonate with 3,000-15,000 viscosity-average molecular weight. The resultant reaction mixture containing the above mentioned polycarbonate is then introduced into the second reaction zone and the caustic alkali is replenished into the reaction system at the same time to adjust the alkali concentration of the second reaction zone to 0.05-0.7 normality followed by polymerization thereof. The reaction is preferably carried out while regulating the temperature of the reaction solution at 10-50°C.
HISANISHI NORIYUKI
YAMAMOTO KOJI
| JPS5437919A | 1979-03-20 |
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