| abstract |
A hydraulic cement composition is effectively dispersed with the use as a dispersion agent of a reaction product obtained by oxidizing and polymerizing a condensate of formaldehyde with a naphthalenesulfonic acid salt and/or an alkylnaphthalenesulfonic acid salt to produce a constitutional unit which is derived by elimination of a methylene group, hydroxyzation and condensation polmerization, or oxidation and ring-opening of the naphthalene ring. |