Patent ID: 7666975

Claim:
A polyketone obtained by polymerization in a liquid medium containing an alcohol of 1-6 carbon atoms and water and having a water content, as represented by the following Expression 1, of 10-500,000 ppm, comprising repeating units, 95-100 mole % of which are 1-oxotrimethylene represented by formula (1) and having an intrinsic viscosity of 2.5-20 dl/g, wherein the content of Pd element is 0-20 ppm, terminal structures include an alkyl ester group (terminal group A) represented by the formula (2) and an alkyl ketone group (terminal group B) represented by formula (3), and the equivalent ratio of terminal group A/terminal group B is 0.1-8.0: (wherein R 1 is hydrocarbon of 1-6 carbon atoms and R 2 is an organic group of 1-10 carbon atoms), Expression 1: Water ⁢ ⁢ content ⁢ ⁢ ( ppm ) = Mass ⁢ ⁢ of ⁢ ⁢ water ⁢ ⁢ ( g ) Volume ⁢ ⁢ of ⁢ ⁢ polymerization ⁢ ⁢ solvent other ⁢ ⁢ than ⁢ ⁢ water ⁢ ⁢ ( ml ) + Volume ⁢ ⁢ of ⁢ ⁢ water ⁢ ⁢ ( ml ) × 10 6 (the volumes in the denominator of the right side are values at 25° C.).