Redistributed polycarbonate resin

A method for producing a redistributed polycarbonate having a narrowed MFI distribution, which method comprises feeding into an extruder a source polycarbonate resin together with a redistribution catalyst for said polycarbonate resin, while using a feedback loop control mechanism for the extruder to adjust a result effective parameter, thereby producing said redistributed resin which has a melt flow distribution narrower than that of said source resin, wherein the redistribution catalyst has an activity ratio of less than 25 molecular weight units per ppm catalyst, wherein the activity ratio is determined over a range of catalyst addition ratios sufficient to produce a percentage molecular weight drop of between 0 to 25%.

A method for producing a redistributed resin having a narrow MFI distribution which comprises extruding a polycarbonate source resin together with a redistribution catalyst for said resin while using a feedback loop control mechanism to adjust addition of said redistribution catalyst, wherein the redistribution catalyst produces a redistributed resin having lowered levels of free monomer;

• and wherein the redistribution catalyst has an activity ratio of less than 25 molecular weight units per ppm catalyst, wherein the activity ratio is determined over a range of catalyst addition ratios sufficient to produce a percentage molecular weight drop of between 0 to 25%.

A method for producing a redistributed thermoplastic resin which comprises feeding a resin and a redistribution catalyst for said resin into an extruder, measuring the current melt temperature, comparing said melt temperature with a set point melt temperature to determine a temperature differential, and adjusting the feeding rate of the redistribution catalyst in response to said temperature differential, wherein the redistribution catalyst produces a redistributed resin having lowered levels of free monomer;

• and wherein the redistribution catalyst has an activity ratio of less than 25 molecular weight units per ppm catalyst, wherein the activity ratio is determined over a range of catalyst addition ratios sufficient to produce a percentage molecular weight drop of between 0 to 25%.

A method for minimizing off-specification polycarbonate produced by a polycarbonate plant, which method comprises producing a master grade of polycarbonate resin at a manufacturing facility, transporting said master grade to a redistribution facility, and redistributing said polycarbonate, wherein said redistribution is accomplished by extruding the master grade polycarbonate resin together with a redistribution catalyst for said resin while using a feedback loop control mechanism to adjust addition of said redistribution catalyst, thereby producing a redistributed resin having a melt flow distribution narrower than that of said source resin.

A redistributed polycarbonate resin having a standard deviation of MFI of less than 0.30 when measured over a period of 8 hours collecting at least 15 data points at equally spaced time intervals.