A modified emulsion of polycarbonate resin, comprising a polycarbonate resin emulsion and a monocarbodiimide compound and/or a polycarbodiimide compound; and a process for producing a modified emulsion of polycarbonate resin, which comprises adding a monocarbodiimide compound and/or a polycarbodiimide compound to a polycarbonate resin emulsion. This modified emulsion of polycarbonate resin is improved in adhesivity, water resistance and chemical resistance.

An optical conductor comprises a fiber, in particular a glass fiber, surrounded by a protective polymer material of the UV-curable type. The protective polymer material contains a water-absorbing additive, preferably a carbodiimide, a poly-carbodiimide, or a polyurea. When the additive is based on carbodiimide, it opposes photodegradation.

A hydrolysis stabilizer for an ester group-containing resin, which comprises as a main component a carbodiimide having at least two carbodiimide groups in the molecule and resulting from 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate or a mixture of 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate, or from a mixture of tetramethylxylylene diisocyanate with 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate or a mixture of 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate; and a process for the hydrolysis stabilization of an ester group-containing resin, which comprises mixing a polyester type resin with the above hydrolysis stabilizer.

Thermoplastic molding compositions comprise A) from 20 to 99% by weight of a polyester, up to 90% by weight of which may be replaced by a polycarbonate or a polyamide, B) from 0.1 to 7% by weight of a carbodiimide of the formula I ##STR1## where R.sup.1 are identical or different radicals selected from the group consisting of --NCO, --NHCONHR.sup.5, --NHCONR.sup.5 R.sup.6 and --NHCOOR.sup.7, where R.sup.5 , R.sup.6 are identical or different and are alkyl, cycloalkyl or aralkyl, R.sup.7 is the same as R.sup.5 or is alkoxy(poly)oxyalkylene and R.sup.2 , R.sup.3 are identical or different aliphatic radicals having from 1 to 18 carbon atoms or cycloaliphatic radicals having from 5 to 15 carbon atoms or aromatic radicals having from 6 to 15 carbon atoms, R.sup.4 are identical or different aliphatic radicals having from 2 to 20 carbon atoms or halogen or alkoxy, x is an integer from 0 to 4 and n is an integer from 0 to 10, C) from 0 to 75% by weight of conventional additives and processing aids, where the sum of the percentages by weight of components A) to C) is 100%.

The present invention relates to compatible blends of, per se incompatible, thermoplastic molding compositions, to methods for the production thereof, and to the use of the blends according to the present invention to produce films, fibers and molded articles.