TERMOPLASTISK POLYKARBONATFORMMASSA VILKEN LOSSNAR LAETT FRAON FORMEN EFTER FORM-PRESSNING

1353340 Polycarbonate moulding compositions BAYER AG 23 Dec 1971 [28 Dec 1970] 59942/71 Heading C3R A moulding composition comprises a polycarbonate of a bishydroxy compound containing as mould release agent, 0À1-2% by weight based on the polycarbonate of at least one ester of a trihydric alcohol and a saturated aliphatic C 10 -C 22 carboxylic acid. The composition may also contain dyestuffs, pigments, stabilizers against ultra-voilet radiation and against heat, dispersing agents and glass fibres. The ester may be incorporated by tumbling granules of the polycarbonate with the ester in powder form and extruding the composition through an extruder at approximately 270‹ C. to form a ribbon which is subsequently granulated, or the polycarbonate granules may be tumbled with a colour concentrate containing the ester with a pigment, e.g. carbon black. Alternatively the ester may be incorporated when the polycarbonate is manufactured by metering the ester dissolved in a solvent into the solvent used in the manufacture of the polycarbonate before evaporation. In examples granules of a polycarbonate prepared by the reaction of the Bisphenol A and phosgene are tumbled with a glyceride containing radicals of palmitic, stearic and myristic acids in the molar ratio of 1 : 1 : 0 : 1, optionally in admixture with titanium dioxide pigment, or with an ester mixture of the glycerides of lauric, myristic and palmitic acids in the molar ratio of 1 : 1 : 1 in admixture with titanium dioxide pigment and glass fibres, extruded at 270‹ C. to give a ribbon and granulated, or granules of the polycarbonate are tumbled with a paste produced by stirring carbon black into the fused ester of trimethylol propane and palmitic and stearic acids in the molar ratio of (1 : 1), extruded at 270‹ C. to give a ribbon and granulated.