To obtain a maleic acid resin compsn. which can be cured by ionization without requiring an additional thermal posttreatment by compounding a maleic acid resin with a specified amt. of a specific reactive diluent.

This compsn., curable by ionization, is prepd. by compounding 100 pts.wt. maleic acid resin with 10-70 pts.wt. reactive diluent comprising dipentaerythritol pentaacrylate and/or hydroxyethyl methacrylate. The resin is produced by reacting an N, N-bismaleimide represented by formula I [wherein Z is CH3 or Cl; and A is a divalent group such as a single bond, CH2C(CH3)2, O, S, or SO2], a maleimide represented by formula II, III, etc., an acrylate reagent represented by formula IV (wherein R1 is H or CH3; and n is an org. group comprising a 1-30C linear or branched satd. aliph. hydrocarbon group optionally having an 0 or 011 group), and a reagent having a vinyl bond (e.g. vinylpyridine or N-vinylpyrrolidone).