e oxide and tetrahydrofuran, polyethylene glycol diglycidyl ether di(meth)acrylate, or a polyol poly(meth)allyl ether or poly(meth)acrylate obtained by adding at least 2 mols of ethylene oxide to 1 mol of a polyhydric alcohol such as bisphenol A, glycerol, trimethylolpropane or pentaerythritol.