Process for producing polycarbonate having terminal hydroxyl groups
AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsShinji Funakoshi, Kenzou Kawai
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AssigneeAsahi Kasei Kogyo Kabushiki Kaisha
InventorsShinji Funakoshi, Kenzou Kawai
Estimating the term…
A process for producing a polycarbonate having terminal hydroxyl groups obtained by reacting an aliphatic polyol with a carbonate monomer, characterized by comprising the first step of producing a low molecular weight polycarbonate while removing the alcohols produced as by-products from the reaction mixture containing the aliphatic polyol and the carbonate monomer and the second step of adding to the reaction mixture the carbonate monomer in portions or continuously under the conditions that the concentration of the aliphatic polyol in the reaction mixture in the first step is 5% by weight or less and effecting the reaction while removing the alcohols produced as by-products, whereby connecting the low molecular weight polycarbonates to one another through the carbonate monomer to heighten the molecular weight.
A process for producing a polycarbonate having terminal hydroxyl groups obtained by reacting an aliphatic polyol with a carbonate monomer selected from the group consisting of a dialkyl carbonate, a diaryl carbonate and an alkylene carbonate, which comprises a first step of producing a low molecular weight polycarbonate while removing alcohols produced as by-products from the reaction mixture containing said aliphatic polyol and said carbonate monomer and a second step of adding to the reaction mixture in the first step said carbonate monomer in portions or continuously under the conditions that the concentration of the aliphatic polyol in the reaction mixture in the first step is 5% by weight or less and subjecting the resulting mixture to reaction while removing the alcohols produced as by-products to connect the low molecular weight polycarbonates to one another through the carbonate monomer, thereby increasing the molecular weight.
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