http://rdf.ncbi.nlm.nih.gov/pubchem/patent/JP-2004537623-A
Outgoing Links
| Predicate | Object |
|---|---|
| classificationCPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C08G64-307 http://rdf.ncbi.nlm.nih.gov/pubchem/patentcpc/C08G64-30 |
| classificationIPCInventive | http://rdf.ncbi.nlm.nih.gov/pubchem/patentipc/C08G64-30 |
| filingDate | 2002-07-19-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationDate | 2004-12-16-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| publicationNumber | JP-2004537623-A |
| titleOfInvention | Polycarbonate production method |
| abstract | The present invention provides a method for melt polymerization of a polycarbonate that provides a high degree of end-blocking while minimizing the production of fleece products. [Solution] Bisphenol A is a two-stage process involving the oligomerization of reactants catalyzed by tetraalkylphosphonium carboxylate in the first reaction stage and the subsequent addition of an alkali metal hydroxide cocatalyst in the second stage of the polymerization reaction. Polycarbonates having a high endcapping ratio and a low Fries rearrangement product content are produced from a dihydroxy aromatic compound such as a diaryl carbonate such as diphenyl carbonate. Late addition of the cocatalyst improves the rate of the polymerization reaction in view of the higher polycarbonate molecular weight. The amount of alkali metal hydroxide cocatalyst is small and the formation of excessive fleece products is avoided. Using this method, fleece product levels of 200-1000 ppm for polycarbonates with Mn greater than 7500 daltons were obtained. |
| priorityDate | 2001-08-08-04:00^^<http://www.w3.org/2001/XMLSchema#date> |
| type | http://data.epo.org/linked-data/def/patent/Publication |
Incoming Links
Total number of triples: 117.