Provided are an amphipathic compound represented by any of the following Formulas: ##STR1## (R.sub.1 is a linear or branched, saturated hydrocarbon group having 6 to 48 carbon atoms, or a linear or branched, unsaturated hydrocarbon group containing 1 to 12 unsaturated double bond and having 6 to 48 carbon atoms; Y is NH, N--(CH.sub.2 --CH.dbd.CH.sub.2), or O; Q is --CH.sub.2 --C(R.sub.2).dbd.CH.sub.2 or --R.sub.4 --O--CO--C(R.sub.2).dbd.CH.sub.2 ; and M is alkali metal, an ammonium group, or --(CH.sub.2 CH.sub.2 O).sub.m H), a copolymer of the amphipatic compound with a copolymerizable ethylenically unsaturated compound and, a paper making additive containing a water soluble or dispersible high molecular compound as an active ingredient and processes for producing these high molecular compounds.