METHOD OF PREPARING CRYSTALLINE AROMATIC POLYCARBONATE PREPOLYMER AND A METHOD OF PREPARING HIGH-MOLECULAR CRYSTALLINE AROMATIC POLYCARBONATE Russian patent published in 1995 - IPC

FIELD: chemical technology. SUBSTANCE: crystalline aromatic polycarbonate prepolymer is prepared by treatment of amorphous aromatic polycarbonate prepolymer with interaction product solvents: a) aromatic dihydroxy-compound with diphenylcarbonate; b) bisphenol A with phosgene; c) polycarbonate prepolymer of bisphenol A with molecular mass 468-800 with terminal arylcarbonate groups, with bisphenol A with molecular mass 2300-9100 at the mole ratio of terminal hydroxylic and arylcarbonate groups (10-90):(90-10). Mixture is stirred in mixer with cutter at the rate at least 250 cm/s, or in mixer with stirrer at the rate at least 6 cm/s. Prepared porous crystalline aromatic polycarbonate prepolymer in powdery, agglomerated powdery or granulated form has the specific square surface at least 0.4 m²/g and crystallinity degree at least 20% High-molecular crystalline aromatic polycarbonate with molecular mass 6000-100000 and crystallinity degree at least 35% is synthesized on the basis of prepared prepolymers by solid-phase polycondensation at heating with simultaneous distillation off of by-side products of polycondensation. Solid-phase polycondensation is carried out in the presence of inert gas feeding to the reaction zone at the rate 0.1-7 l/h per one gram prepolymer occurring in powdery or agglomerated powdery form, or at the rate 0.1-50 l/h per one gram prepolymer occurring in granulated form. Inert gas can contain polycondensation by-side products at concentrations corresponding partial pressure of polycondensation by-side product not more than 5 mm mercury column. Method is used for preparing optically transparent articles. EFFECT: improved method of preparing. 6 cl, 3 tbl