| abstract |
(57) [Summary] [Objective] It is an object of the present invention to find out a method for preventing polymerization which can exhibit a polymerization preventing effect even in a small amount even in a step where (meth) acrylic acid and its ester are easily polymerized. [Structure] As a polymerization inhibitor, one or more selected from the group consisting of a manganese salt compound, a copper salt compound, a 2,2,6,6-tetramethylpiperidine compound and a nitroso compound are used together with an N-oxyl compound. |