. "In addition, other polymerizable monomers, for example, ??-olefins such as propylene, 1-butene, etc.; unsaturated carboxylic acids or esters thereof such as (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, etc.; vinylpyrrolidone compounds such as N-vinylpyrrolidone, etc.; can also be used as a component for copolymerization, so far as it does not adversely affect the object of the" . . . .