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AssigneeGeneral Electric Company
InventorsAllen W. Ko, John B. Starr, Jr.
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A process for the production of a substantially clear and colorless, or at most slightly tinted, polyarylcarbonates useful to form molded structural and engineering articles suitable to replace metal parts, or for use in electrical appliances to form lenses, safety shields, instrument windows and the like is disclosed. The tendency of color formation in polycarbonates and polyarylates prepared by transesterification and polycondensation is reduced or inhibited by carrying out the transesterification reaction while the reaction mixture contacts only metal surfaces of selective metals, or glass. The metal surfaces are provided by such metals as tantalum, nickel, or chromium or mixtures thereof. The reaction is carried out in reactors or systems which are substantially totally made of such metals, or reactors or systems clad or lined with a layer of such metals or glass. In its broad aspects the invention comprises carrying out the reaction in the substantial absence of metals selected from the group consisting of iron, tin, lead, titanium, vanadium, zirconium, stainless steel, and Group IIIA metals, namely, aluminum, gallium, indium and thallium. The preferred method of carrying out the reaction is in the absence of metals other than nickel, tantalum and chromium or mixtures thereof.
In a process for the preparation of a moldable polyarylate or polyaryl carbonate by transesterification and polycondensation of
In a process for the preparation of a moldable polyarylate or polyaryl carbonate by transesterification and polycondensation of
A process for the preparation of a moldable polyarylate or polyaryl carbonate by transesterification and polycondensation of
In a process for the preparation of a moldable polyarylate or polyaryl carbonate by transesterification and polycondensation of
A process for the prevention of undesired color formation in the course of preparing a moldable polyarylate or polyaryl carbonate polymer said process comprising:
Dependencies are inferred from the claim text.