Reacting polycarbonate resin with aryl chlorocarbonate to improve aging characteristics
First Claim
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1. A process for the preparation of a polycarbonate resin having a weight average molecular weight of at least 10,000 as determined by gel chromatography comprising reacting:
- (A)(i) at least one member selected from the group consisting of diphenols of the formula (I) HO--Z--OH wherein Z is a divalent aromatic radical and chlorocarbonic acid esters of a diphenol,(ii) about 0.1 to 8 mol % of phenol or a substituted monophenol and(iii) phosgene, in an organic solvent and an aqueous alkaline phase to produce a polycarbonate resin, and reacting(B) the polycarbonate resin of said (A) in solution in the organic phase after the aqueous alkaline phase has been separated off and before any acidic wash with about 0.1 to 1 mol % of at least one aryl chlorocarbonate of the formula (II) ##STR3## wherein Ar denotes a monovalent aromatic radical, said percents being relative to the mols of said (i).
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Abstract
A process for the preparation of polycarbonates from diphenols and/or chlorocarbonic acid esters thereof and phosgene by the two-phase boundary process wherein said polycarbonate is reacted with aryl chlorocarbonate is disclosed; the reaction products are noted for their improved ageing and hydrolysis characteristics which render them useful as thermoplastic molding compositions.
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8 Claims
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1. A process for the preparation of a polycarbonate resin having a weight average molecular weight of at least 10,000 as determined by gel chromatography comprising reacting:
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(A) (i) at least one member selected from the group consisting of diphenols of the formula (I) HO--Z--OH wherein Z is a divalent aromatic radical and chlorocarbonic acid esters of a diphenol, (ii) about 0.1 to 8 mol % of phenol or a substituted monophenol and (iii) phosgene, in an organic solvent and an aqueous alkaline phase to produce a polycarbonate resin, and reacting (B) the polycarbonate resin of said (A) in solution in the organic phase after the aqueous alkaline phase has been separated off and before any acidic wash with about 0.1 to 1 mol % of at least one aryl chlorocarbonate of the formula (II) ##STR3## wherein Ar denotes a monovalent aromatic radical, said percents being relative to the mols of said (i). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification