. . "f 2 to 4 carbon atoms, providing two or more species of the mixture may be added either in the form of a block or in a random form, R3 for a hydrogen atom or an alkyl group of 1 to 5 carbon atoms, and m is a value indicating the average addition mol number of oxyalkylene groups that is an integer in the range of 1 to 100, 95 to 2% by weight of a (meth)acrylic acid monomer (b) represented by the ab" . . .