PURPOSE: To obtain the modified polyester excellent in bondability, transparency, and recovery from curling by incorporating given amounts of specific compounds into a polyester.
CONSTITUTION: The polymer comprises a polyester [e.g. poly(ethylene terephthalate)] and, incorporated therein, 1-30wt.% ester-forming alkali metal sulfonate compound (e.g. dimethyl 5-sodiumsulfoisophthalate), 1-20wt.% compound which is either a dicarboxylic acid containing an ether linkage or an ester- forming derivative thereof and is represented by the formula (wherein R1 is a 4C or higher divalent hydrocarbon group; R2 and R3 each is H or an alkyl; k and j each is 2-4; q is 0 or 1; p is 1-3; and m+n≥4, provided that either may be 0) (e.g. poly(oxyethylene)diglycolic acid), and 0.1-15wt.% poly(oxyalkylene)glycol [e.g. poly(ethylene glycol)].
HIRANO TAKUMI
SUZUKI MASARU
