A Polish epoxy resin, Epidian 2 (epoxy no. 0.25), heated with methacrylic acid, hydroquinone and 2,4,6-(dimethylamino-methyl)phenol at 80-120degreesC for 7 hours until acid no. was nil, gave the methacrylic ester. This was modified with to-luylene diisocyanate in styrene as solvent under N-2 at 50-60degreesC until no free -NCO groups were detectable. The modified and nonmodified resins were cured with 2 wt. pts. Et-Me ketone hydroperoxide and 0.6 wt.pts. styrenic 1% Co cobalt(II) octenate at room temp. for 24 and at 80degreesC for 4 hours. The modification resulted in shorter gel time, lower max. copolymn. temp., higher viscosity, higher impact and tensile strengths, lower bending strength, and higher glass transition temps. In painter's naphtha and tap water the wt. increments were -0.5-0.2% and, less than or equal to0.6% in 70 days, resp.; in toluene most resins underwent destruction in 1-2 weeks.