Method for producing polycarbonate molding compositions with improved thermal processing stability

Abstract

The invention relates to a compounding method for producing impact-modified polycarbonate compositions using components acting as an alkali or using alkaline constituent-containing components. By using the method according to the invention, the harmful influence of the components acting as an alkali on the properties of polycarbonate molding compositions or the surface of molded bodies produced therefrom is counteracted. The method has the steps (i), (ii), and optionally (iii), wherein (i) in a first step A) 10 to 98 wt. % of at least one polymer selected from the group of aromatic polycarbonates and aromatic polyester carbonates, B) 0.001 to 0.3 wt. % of at least one organic Brønsted acid, i.e. a carbon and hydrogen-containing Brønsted acid, C) 0.0001 to 0.008 wt. % of at least one inorganic Brønsted acidic phosphorus compound, i.e. a Brønsted acidic phosphorus compound which does not contain carbon, D) 1 to 90 wt. % of at least one rubber-containing vinyl(co)polymerisate, E) 0 to 90 wt. % of at least one polyester, and F) 0 to 30 wt. % of at least one additive, the ratio of the weight percentages of the components B to C used in method step (i) ranging from 2 to 100, are heated by supplying thermal and/or mechanical energy, whereby at least the components A) and D) are melted and all of the components used are mixed together, dissolved into one another, or dispersed into one another, and in an additional step (ii), the melt (ii) resulting from method step (i) is resolidified by cooling and (iii) optionally granulated. The method steps (ii) and (iii) can be carried out in any order. The invention also relates to compositions produced according to the method, to the use thereof for producing molded bodies, to the molded bodies themselves, and to the use of the mixtures of B and C for stabilizing impact-modified polycarbonate compositions.