Stabilized isocyanate group-containing ethylenically unsaturated compound

A stabilizing composition for an isocyanate group-containing ethylenically unsaturated compound, comprising:

• an isocyanate group-containing ethylenically unsaturated compound (A) which comprises one or more isocyanate groups and one or more ethylenically unsaturated groups represented by following formula (1);
• and
• a stabilizing agent (B) which is a compound having the same structure as compound (A) except that at least one of the ethylenically unsaturated groups represented by formula (1) in the compound (A) is replaced with a structure represented by following formula (2) or (3):
• —CR1═CR2R3 (1)
• wherein R1 to R3 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an aromatic group;
• —CR4R5—CR6R7R8 (2)
• wherein R4 to R8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an aromatic group;
• —CR9R10R11 (3)
• wherein R9 to R11 each independently represent a hydrogen atom or an aromatic group;
• and
• wherein none of R1 to R11 includes a substituent.