Poli(ossi-1,2-etandiile), α-carbossimetil-ω-idrossi-, C12-13-alchil eteri (7 mol EO rapporto molare medio) ###>Poly(oxy-1,2-ethanediyl), .alpha.-carboxymethyl-.omega.-hydroxy-, C12-13-alkyl ethers (7 mol EO average molar ratio)