Method for the manufacture of aromatic polycarbonate
First Claim
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1. An improved method for manufacturing an aromatic polycarbonate by melt polycondensation of a dihydric aromatic compound and a carbonic acid diester wherein the polycarbonate melt is formed in at least two reactors in series, one of which is a final reactor, wherein the improvement comprises filtering the melt before the final reactor through a filter having an absolute filtration accuracy above 0.5 μ
- m but below 5 μ
m and filtering the melt at the final reactor outlet through a filter having an absolute filtration accuracy above 5 μ
m but below 30 μ
m whereby the polycarbonate is suitable for optical applications or precision parts.
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Accused Products
Abstract
Aromatic polycarbonates manufactured by polycondensation of a dihydric compound and a carbonic acid diester using at least two reactors in series have improved color and low impurities content when filtered before the final reactor and again before the final reactor outlet.
59 Citations
3 Claims
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1. An improved method for manufacturing an aromatic polycarbonate by melt polycondensation of a dihydric aromatic compound and a carbonic acid diester wherein the polycarbonate melt is formed in at least two reactors in series, one of which is a final reactor, wherein the improvement comprises filtering the melt before the final reactor through a filter having an absolute filtration accuracy above 0.5 μ
- m but below 5 μ
m and filtering the melt at the final reactor outlet through a filter having an absolute filtration accuracy above 5 μ
m but below 30 μ
m whereby the polycarbonate is suitable for optical applications or precision parts. - View Dependent Claims (2, 3)
- m but below 5 μ
Specification
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Current AssigneeSabic Innovative Plastics IP BV (Government of Saudi Arabia)
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Original AssigneeGeneral Electric Company
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InventorsMiura, Kimiyoshi, Sakashita, Takeshi, Shimoda, Tomoaki, Kanezawa, Akio, Tominari, Kenichi
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Primary Examiner(s)Seidleck, James J.
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Assistant Examiner(s)BOYKIN, TERRESSA M
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Application NumberUS08/353,857Time in Patent Office547 DaysField of Search526/64, 526/65, 526/67, 526/71, 528/196, 528/198, 528/199, 528/200, 528/201, 528/204, 528/219, 528/271, 528/272, 528/274, 528/275, 528/288, 210/323.1, 502/150, 502/152, 502/157, 502/200, 502/202US Class Current528/199CPC Class CodesB01J 19/1862 placed in seriesB01J 2219/00168 controlling the viscosityC08G 64/205 characterised by the appara...C08G 64/307 and phenols
