Impact-modified polycarbonate compositions having a good combination of natural color, hydrolytic stability and melt stability

Abstract

The present invention relates to polycarbonate compositions comprising

• • A) from 10 to 99 parts by weight, in each ease based on the sum of components A+B+C, of aromatic polycarbonate and/or aromatic polyester carbonate,
  • B) from 1 to 35 parts by weight, in each case based on the sum of components A+B+C, of rubber-modified graft polymer of
    • B.1 from 5 to 95 wt. % of at least one vinyl monomer on
    • B.2 from 95 to 5 wt. % of one or more graft bases having a glass transition temperature <10° C.,
  • C) from 0 to 40 parts by weight, in each case based on the sum of components A+B+C, of vinyl (co)polymer and/or polyalkylene terephthalate,
  • D) from 0 to 50 parts by weight, in each case based on the sum of components A+B+C, of phosphorus-containing flameproofing agent,
  • E) from 0 to 1.0 part by weight, in each case based on the sum of components A+B+C, of acidic additives, and
  • F) from 0 to 50 parts by weight, in each case based on the sum of components A+B+C, of additives,
  • wherein component B is obtainable by reacting component B.1 with the graft base B.2 by means of emulsion polymerization, with the proviso that in those compositions that are free of components D) and E), the graft polymer dispersion in the spray drying or in the precipitation has a pH value of less than 7,
  • characterized in that there are used in the graft reaction from 0.1 to 5 parts by weight (based on the sum of the parts by weight of the monomers B.1 and of the graft base B.2 that are used=100 parts by weight) of at least one emulsifier selected from the group consisting of alkali, alkaline earth, ammonium and phosphonium salts of a saturated fatty acid having from 10 to 50 carbon atoms, wherein the emulsifier or emulsifiers remains or remain in component B,

and also to a process for the preparation of these polycarbonate compositions and to the use of the polycarbonate compositions in the production of molded bodies, and to the molded bodies themselves.

Description

CROSS REFERENCES TO RELATED APPLICATIONS[0001]This application claims priority to DE 10 2008 015 407.5 filed Mar. 22, 2008 the content of which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to polycarbonate compositions comprising as impact modifier specific rubber-containing graft polymers prepared by the process of emulsion polymerization, and also to a process for the preparation of these polycarbonate compositions and to the use of the polycarbonate compositions in the production of molded bodies, and to the molded, bodies themselves.[0004]2. Description of Related Art[0005]Polycarbonate compositions comprising graft polymers as impact modifiers can have varying stability to hydrolysis and thermal stress depending on the purity of and the additives in the impact modifier, for example ABS (acrylonitrile-butadiene-styrene terpolymer). For example, B. S. Patty, L. Novak and H. Phan (...

AI Technical Summary

Benefits of technology

[0010]An object of the present invention was to provide impact-modified polycarbonate molding compositions comprising at least one emulsion graft polymer as an impact modifier. Compositions of the present invention are distinguished, inter alia, by a combination of a light natural color, high hydrolytic stability and excellent processing stability. Compositions of tire present invention additionally, advantageously fulfill the condition that they comprise an emulsion graft polymer that is prepared in a preparation process that is efficient and advantageous for the environment.

Problems solved by technology

), which are accompanied by impaired processing stability.

These emulsifiers frequently lead to undesirable discoloration of the molding compositions.

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