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Process for preparing polycarbonate

A technology of polycarbonate and diaryl carbonate, applied in the field of polycarbonate preparation, can solve problems such as being harmful and affecting the mechanical and physical properties of polycarbonate

Inactive Publication Date: 2007-09-12
SABIC GLOBAL TECH BV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In many cases, however, the basic catalysts used in the transesterification reaction cause the formation of crosslinked moieties leading to the formation of branched polycarbonate structures during heating and / or depressurization
The formation of branched species can adversely affect the mechanical and physical properties of the finished polycarbonate

Method used

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  • Process for preparing polycarbonate
  • Process for preparing polycarbonate
  • Process for preparing polycarbonate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0051] In this example, diphenyl carbonate and bisphenol A were polymerized with a sodium hydroxide catalyst to obtain an intermediate polycarbonate having a molecular weight of 5,000-8,000 Daltons. The amount of catalyst used in this reaction was 1×10 -6 mole / mole bisphenol A, and set it as 1 equivalent in order to determine the addition amount of branched quencher. Except as indicated in the text, the polycarbonate was then further processed in a small reactor at 300°C. The pressure in the autoclave was gradually reduced to 1 mbar and after 30 minutes a finished polycarbonate with a molecular weight of 15,000-18,000 Daltons was obtained. The relative change in branching was monitored as a function of the number of equivalents of branch quencher compound (based on catalyst concentration) added to the molten polycarbonate. The results are shown in Table I.

[0052] project

branch quencher

per mole of catalyst

Equivalent number

% Quenching

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Abstract

A method for preparing polycarbonates by melt polycondensation of a dihydroxy compound and a diarylcarbonate compound in the presence of an alkaline catalyst is described. A branching quencher compound is added to an intermediate polycarbonate produced by the melt polycondensation reaction in an amount effective to inhibit or prevent the formation of branching species during a subsequent finishing process. Adding the branching quencher compound to the product of the melt polycondensation reaction produces finished polycarbonates with reduced branching species, high ductility and impact strength.

Description

Background of the invention [0001] The present invention relates to a process for the production of polycarbonate, and more particularly to a process for the production of polycarbonate by catalyzed melt polycondensation of a dihydroxy compound and a diaryl carbonate in the presence of a catalyst. [0002] Aromatic polycarbonates are used in a variety of applications due to their excellent mechanical and physical properties, including impact and heat resistance, strength and clarity. Three common processes are known for the industrial production of aromatic polycarbonates, which are diagrammed in FIG. 1 . The conventional interfacial approach as shown in FIG. 1A and the phosgene-based fusion process as shown in FIG. 1B start from the reaction of phosgene with carbon monoxide. A third commonly used method, the "phosgene-free" fusion method shown in Figure 1C, was developed to exclude the use of highly toxic phosgene in the process flow. Among these commonly used methods, the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G64/00C08G64/30
CPCC08G64/307
Inventor 安德烈·A·沃尔克斯马塞尔·A·F·普伊恩
Owner SABIC GLOBAL TECH BV