Abstract: A process is provided for preparing a polycarbonate composition with excellent weatherproof properties. The process comprises adding an ultraviolet absorbing compound having a hydroxy group which contributes at least partially to the molecular weight modifier to an oligomeric polycarbonate which is obtained by the reaction of a dioxy compound with phosgene, and then condensing said oligomeric polycarbonate to polymerize the same.

Abstract: Polycarbonate oligomer having uniform qualities is prepared by reacting an aqueous alkaline solution of 2,2-(4,4'-dihydroxydiphenyl) propane with phosgene in the presence of methylene chloride and as a characteristic point of this method, in the presence of an inert gas in an amount of 1 to 10 mol % based upon the phosgene.

Abstract: In the method for producing a high impact polystyrene from a monomer of styrene or/and its derivative and a rubbery polymer as reactants, an improvement is provided which comprises passing said reactants through a tubular reactor having parts where the passage way of flow of said reactants is constricted, while keeping said reactants in a laminar flow as much as possible in the parts other than said parts, in a first stage polymerization to prepare a reacted mixture containing a prepolymer until the conversion of monomer to polymer becomes 10 to 60%, and subjecting the resulting reacted mixture to a second stage polymerization in the state where almost no shearing is exerted thereupon.The shearing during said first stage polymerization can be uniformly carried out.The resulting product has superior high impact properties.

Abstract: A heat resistant and impact resistant polycarbonate having a narrow distribution of molecular weight is continuously produced by reacting chloroformate ester, prepared in advance by reacting alkaline solution of dioxy compound in a turbulent flow of the two solutions while cooling and subsequently reacting the mixture concurrently in a laminar flow after the viscosity of the mixture has become significant.