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AssigneeDaicel Chemical Industries, Ltd.
InventorsYoshimichi Okano, Michiyo Tanigawa, Yutaka Fukuda
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A (co)polycarbonate composition mainly comprising a (co)polycarbonate having a limiting viscosity number [.eta.] of 0.2 to 1.0 dl/g and terminal hydroxyl groups in an amount of 20 mole % or below, based on all the terminal groups of the (co)polycarbonate, and is substantially free from any branched structure which might otherwise be formed by a side reaction. The (co)polycarbonate contains chlorine (causasive of discoloration) in an amount of 10 ppm or below and an alkali metal ion and/or an alkaline earth metal ion in an amount of 1 ppm or below. A process for preparing the above (co)polycarbonate composition by the melt transesterification process involves the reaction of a dihydroxy compound such as bisphenol A and a carbonic diester such as diphenyl carbonate with a nitrogen-containing basic compound (a), and/or, a compound (b) containing an element selected from the group consisting of elements belonging to Groups I, II, IV and V of the periodic table as a catalyst.
A (co)polycarbonate product comprising a (co)polycarbonate only containing no more than 10 ppm of chlorine ion and no more than 1 ppm of alkali metal ion and alkaline earth metal ion as impurities, said (co)polycarbonate having a limiting viscosity number .eta. of 0.2 to 1.0 dl/g, said limiting viscosity number .eta. being determined by a solution made up of the (co)polycarbonate in methylene chloride at 20.degree. C., a total terminal hydroxyl group content of no more than 20 mole % and a branching parameter G of 0.1 to 1.0.
A process for preparing a (co)polycarbonate only containing no more than 10 ppm of chlorine ion and no more than 1 ppm of alkali metal ion and alkaline earth metal ion as impurities, said (co)polycarbonate having a limiting viscosity number .eta. of 0.2 to 1.0 dl/g, said limiting viscosity number .eta. being determined by a solution made up of the (co)polycarbonate in methylene chloride at 20.degree. C., a total terminal hydroxyl group content of no more than 20% and a branching parameter G of 0.1 to 1.0, said process comprising a step of reacting a dihydroxy compound with a carbonic diester in a melt transesterification reaction, the carbonic diester being used in an amount of 0.9 to 1.50 mol per mole of the dihydroxy compound, in the presence of a transesterification catalyst of 10.sup.-7 to 10.sup.-1 mol of a nitrogen-containing basic compound or 10.sup.-8 to 10.sup.-3 mol of an element selected from Groups I, II, IV or V of the periodic table
A (co)polycarbonate product comprising a (co)polycarbonate only containing from 3.1 to 10 ppm of chlorine ion, not more than 1 ppm of an alkali metal ion and an alkaline earth metal ion and not more than 1 ppm of iron ion, said (co)polycarbonate having a limiting viscosity number .eta. of 0.2 to 1.0 dl/g, said limiting viscosity number .eta. being determined by a solution made up of the (co)polycarbonate in methylene chloride at 20.degree. C., a total terminal hydroxyl group content of no more than 20 mole % and a branching parameter G of 0.1 to 1.0.
Dependencies are inferred from the claim text.