Patent ID: 7189797

Claim:
A process for producing a poly(ethylene aromatic carboxylate ester) resin comprising polycondensing a diester of an aromatic dicarboxylic acid with ethylene glycol in the presence of a catalyst system, wherein the catalyst system comprises at least one member selected from the group consisting of: non-reacted mixtures and reaction products of (1) a titanium compound component comprising at least one member selected from the group consisting of titanium alkoxides and reaction products of titanium alkoxides with aromatic polyvalent carboxylic acids or anhydrides thereof with (2a) a phosphorus compound component comprising at least one member selected from the compounds represented by the general formula (1): wherein R 1 , R 2 and R 3 respectively and independently from each other represent an alkyl group having 1 to 4 carbon atoms and X represents a —CH 2 — group or a group represented by the formula (1a): the catalyst system satisfying the requirements (a), (b) and (c): 2≦M Ti ≦15 (a) 1≦(M p /M Ti )≦15 (b) 10≦(M Ti +M p )≦100 (c) in which requirements (a), (b) and (c), M Ti represents a ratio of the amount in the units of milli moles of titanium element contained in the catalyst system to the total amount in the units of moles of the repeating ethylene aromatic dicarboxylate ester units in the poly(ethylene aromatic dicarboxylate ester), M p represents a ratio of the amount of phosphorus element in the units of milli moles contained in the catalyst system to the total amount in the units of moles of the repeating ethylene aromatic dicarboxylate ester units in the poly(ethylene aromatic dicarboxylate ester).