Modified polycarbonates having improved surface properties

#This application is a national stage application (under 35 U.S.C. §371) of PCT/EP2009/005505, filed Jul. 30, 2009, which claims benefit of German application 102008036406.1, filed Aug. 5, 2008.

#The present invention relates to the use of imide-containing aryl mono- and dihydroxy compounds as chain terminators and, respectively, monomer units for the production of polycarbonates, and also to polycarbonates comprising structures derived from imide-containing aryl hydroxy compounds, to processes for the production of the polycarbonates, to mouldings and extrudates obtainable from the said polycarbonates, and also to processes for the production of the mouldings and extrudates.

#The high heat resistance of polycarbonates permits their use inter alia in sectors where they are likely to encounter high temperatures. Specific copolycarbonates (an example being a copolycarbonate based on bisphenol A and bisphenol TMC (1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane)) can give a further increase in heat resistance. The said polycarbonates are therefore also suitable for the production of lenses, reflectors, lamp covers and lamp housings, etc.

#In order to study metallizing properties, rectangular injection-moulded plaques of dimensions 155×75×2.3 mm were prepared. Melt temperature was 300° C. and mould temperature was 100° C. The respective pellets were dried for 5 hours at 120° C. in a vacuum oven prior to processing.

#Metallizing Process:

#Before the test specimens were introduced into the vacuum chamber they were freed from dust by blowing with ionized air. The vacuum chamber with the test specimens was then evacuated to a pressure p≦1·10−5 mbar. Ar gas was then introduced up to a pressure of 5·10−3 mbar. DC magnetron sputtering was used to apply an aluminium layer of thickness 200 nm to the specimens, using a power density of 2.9 W/cm2. The specimens were located on a specimen dish which rotated at 20 rpm during the coating process. The sputter time was 12.5 min.