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US 4,374,961 AGranted
Method for manufacturing heat-stable polyesters using phosphonic acid compounds with cyclic carbonates and catalyst
AssigneeUnitika Ltd.
InventorsKazushige Kudo, Yoshihiro Arai, Ryoichi Tsurutani, Shun-ichi Kiriyama
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Abstract
This invention is a method of manufacturing heat-stable polyesters, characterized in that phosphonic acid compounds are added, when heat-stable polyesters with decreased terminal carboxyl groups are manufactured by reacting polyesters and cyclic carbonate compounds in the presence of an alkali halide compound catalyst.
Claims6
In a method to manufacture heat-stable polyester using cyclic carbonate compounds catalyzed with an alkali halide compound, the improvement comprising
- adding a phosphonic acid compound of the structure ##STR3## wherein R is hydrogen, a monovalent hydrocarbon group with a carbon atom number of 1-18, R.sub.4 OH, COOR.sub.5, or R.sub.6 COOR.sub.7 ;
- R.sub.4 and R.sub.6 are difunctional hydrocarbon groups with carbon atom numbers of 1-18;
- R.sub.5 and R.sub.7 are hydrogen, monofunctional hydrocarbon groups with carbon atom numbers of 1-18 or R.sub.4 OH.
Dependencies are inferred from the claim text.