PURPOSE: To obtain a polymer useful as a modifying agent which promotes the rate of crystallization of polyethylene terephthalate, by a method wherein a copolymer of ethylene and an α,β-unsaturated carboxylic acid is mixed with a polyester amide in molten state.
CONSTITUTION: (A) A copolymer of ethylene and an α,β-unsaturated carboxylic acid or a derivative thereof is mixed in molten state with (B) a polyester amide in which molar ratio of ester bond to amide bond is 25:1W1:25 in an amount ranging from 1/100W2/3 times by weight of the copolymer (A). Preferred copolymer of (A) is a graft copolymer obtd. by polymerizing a copolymer of ethylene and an α-olefin having not less than three carbon atoms such as propylene or butene-1 with an α,β-unsaturated carboxylic acid or anhydride thereof such as maleic anhydride.
YOSHIMURA KAN
OIKAWA TAKASHI
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