from 7 to 12 y is an integer from 7 to 12 z 1 to 20 r 39 is c11h22 guerbet alcohols have been known since the 1890 39 s when marcel guerbet first synthesized these materials m guerbet c r acad sci paris 128 511 1002 1899 these materials are high in molecular weight and are liquid even at very low temperatures the guerbet alcohols used in the present invention contain from about 12 to 40 carbon atoms total in the guerbet alcohol molecule preferably the total number of carbon atoms in the guerbet alcohol molecule will be from about 20 to 36 carbon atoms and in particular 20 carbon atoms in each guerbet alcohol it is known in the art that guerbet alcohols may be formed from the same or different alcohols i e a homo or hetero system that is a guerbet alcohol is the condensation product of two alcohol molecules joined at the beta carbon of the alcohol which has retained the hydroxyl functionality the resultant product is therefore a highly branched primary alcohol containing a single hydroxyl group it is possible to obtain mixtures of alcohols and to condense them into hetero systems it is also possible to obtain products which are guerbet alcohols from a short chained alcohol it is desired for reasons of polarity compatibility with and solubility in the polycarbonate system that homo guerbet alcohols having between 16 and 40 carbon atoms be used it will be observed in the present invention that the mold release agents of this invention result in polycarbonate products in which neither the clarity nor the structural integredity is not adversely affected the polyesters of the present invention are observed to migrate sufficiently from the polycarbonate resin to the surface of the mold to.