Heat stabilization or aromatic polycarbonates

DETAILED DESCRIPTION We claim: 1.
A thermoplastic molding composition comprising (a) a resin selected from the group consisting of polycarbonate and polyester carbonate, and (b) about 0.
01 to 20.
0 percent of at least one silicon compound selected from the group consisting of ##STR11## in which X and Y, both denote -OCH(CH3)CH2)-OCH.
sub.
3 or ##STR12## in which X and Y both denote OCH(CH.
sub.
3)CH.
sub.
2 OCH.
sub.
3.




Description:
This invention relates to silicon compounds corresponding to formulae (I) ##STR1## in which X represents hydrogen [only for formula (I)], C.
sub.
1 -C.
sub.
20 -preferably C.
sub.
1-10 alkyl, -alkoxy, -alkylether, -alkoxyether, -aryl or C.
sub.
3-10 alkoxyoxetane, Y represents hydrogen, C.
sub.
1 -C.
sub.
2 -preferably C.
sub.
1-10 alkyl, -alkoxy, -alkylether, -alkoxyether, -aryl or C.
sub.
3-10 alkoxyoxetane, Z represents phenyl, C.
sub.
1-10 alkyl; the alkyl may be branched and/or unbranched, n is an integer of 1 to 100, preferably 1 to 50 and, more preferably, 1 to 20, m is an integer of 1 to 100, preferably 1 to 50 and, more preferably 1 to 20 and o is an integer of 1 to 100, preferably 1 to 50 and, more preferably 1 to 20.
The silicon compounds corresponding to formulae (I), (II) and (III) are synthesized by the standard methods described in the literature (see, for example, Houben-Weyl, Methoden der Organisthen Chemic, Vol.
XIII/5, Organo-Silicium-Verbindungen (Organosilicon Compounds), Georg Thieme Verlag, Stuttgart/New York, 1980, pages 199 et seq.
).
The present invention also relates to aromatic polycarbonates and/or aromatic polyester carbonates containing 0.
01% by weight to 20% by weight, preferably 0.
01% by weight to 10.
0% by weight and especially 0.
05% by weight to 5.
0% by weight, based on the quantity of polycarbonate and/or polyester carbonate used, of silicon compounds corresponding to formulae (1) and/or (II) and/or (III) above.
By virtue of their physical properties, the thermoplastic polycarbonates and/or polyester carbonates are suitable for optical applications, particularly at relatively high temperatures