| 摘要 |
An improved process for the preparation of high molecular weight, linear polyester resins comprises reacting an aromatic dicarboxylic acid with an excess of an alkane diol under conditions effective to reach the clearing point of the reaction; pre-condensing the cleared reaction mixture under conditions effective to produce oligomers having an intrinsic viscosity measured in 60/40 phenol/1,1,2,2-tetrachloroethane at 25° C. of less than about 0.70 deciliters/gram and a carboxylic acid end group level of less than or equal to about 100 milliequivalents per kilogram; and polycondensing the oligomer under conditions effective to produce a linear polyester resin having an intrinsic viscosity less than or equal to about 2.0 dl/g as measured in 60/40 phenol/1,1,2,2-tetrachloroethane by weight at 25° C. and a carboxylic acid end group level of about 10 to about 40 milliequivalents per kilogram.
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