Poly(oxy-1,2-ethandiyl), α-(carboxymethy)-ω-hydroxy-, C14-15-Alkylether, Natriumsalze (durchschnittliches Molverhältnis 7 Mol EO) ###>Poly(oxy-1,2-ethanediyl), .alpha.-(carboxymethyl)-.omega.-hydroxy-, C14-15-alkyl ethers, sodium salts (7 mol EO average molar ratio)