US 6,635,710 B2 · Manufacturing method for polycarbonate

Abstract

A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10−8 to 1×10−6 mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.

Claims5

Dependent claims

A method of making polycarbonate comprising

melt polycondensing a carbonic acid diester and a bisphenol containing an alkali metal compound or alkaline earth metal compound and determining the transesterification activity of the bisphenol containing an alkali metal compound or an alkaline earth metal compound;
comparing the transesterification activity of the bisphenol containing an alkali metal compound or an alkaline earth metal compound to a calibration curve relating the transesterification activity of pure bisphenol to the amount of bisphenol A disodium salt per mole of pure bisphenol in a melt polycondensation reaction;
and
adjusting the amount of alkali metal compound or alkali earth metal compound in the bisphenol containing an alkali metal compound or alkaline earth metal compound to attain transesterification activity equivalent to the transesterification activity of pure bisphenol containing about 1×10−8 to 1×10−6 moles bisphenol A disodium salt.

1 more element

Dependencies are inferred from the claim text.

Manufacturing method for polycarbonate

Life of this patent

Manufacturing method for polycarbonate

Life of this patent

Abstract

Claims5