PROCESS FOR THE PREPARATION OF A POLYCARBONATE

• Main Authors: BRUYNSEELS, Frank, DECLOEDT, Johan, WUYTACK, Wim, VANDEN EYNDE, Johan, LIESENFELDER, Ulrich Dr
• Format: Patent
• Language: English; French; German
• Published: 05.01.2022
• Subjects: AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; ALLOYS; CHEMISTRY; COMPOSITIONS BASED THEREON; FERROUS OR NON-FERROUS ALLOYS; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS; MAKING GRANULES OR PREFORMS; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PREPARATION OR PRETREATMENT OF THE MATERIAL TO BESHAPED; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIALCONTAINING PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

The present invention relates to a process for the preparation of a polycarbonate by a melt transesterification process or by a phase transfer process. The process according to the invention is characterized in that a finished polycarbonate having a mean molecular weight of 15,000 g/mol to 60,000 g/mol is passed through an orifice in a die plate comprising a number of such orifices, each orifice comprising an insert. The insert used in the process according to the invention is in form of a bushing and this insert essentially consist of an alloy comprising equal to or less than 5 wt.-% Fe. Particularly the alloy comprises the following components:(a) equal to or less than 5 wt.-% Fe,(b) equal to or more than 40 wt.-% Ni,(c) equal to or more than 15 wt.-% Cr,(d) equal to or more than 10 wt.-% Mo,(e) equal to or less than 5.5 wt.-% W,(f) equal to or less than 24.5 wt.-% other components,wherein the sum of the amounts of Fe, Ni, Cr, Mo, W and the other components adds up to 100 wt.-%.