To provide a method for producing a flame-retardant polyester copolymer exhibiting high flame-retardancy (equivalent to V-0 in the UL-94 standard) even if its thickness is 2 mm such as in use for a copying machine casing and the like.
The production method of a flame-retardant polyester copolymer includes a first step and a second step. In the first step, an oligomer is obtained by adding a catalyst to a 2,5-furan dicarboxylic acid compound represented by formula (1), an aliphatic or alicyclic diol, an itaconic acid and a 9,10-dihydro-9-oxa-10-phosphaphenanthren-10-oxide. In the second step, the flame-retardant polyester copolymer is obtained by adding a catalyst to the oligomer obtained in the first step to conduct polycondensation. In the formula (1), X is a hydroxy group, an alkoxy group, or a halogen atom.
ITO KENJI
KUBOTA SUMIRE
FUSHIYA ATSUSHI
SHINAGAWA HIROSHI
