USE OF DISPERSION TYPE POWDER CONTAINING WATER-SOLUBLE SALT OF SULFONATED FORMALDEHYDE CONDENSATION PRODUCT IN HYDRAULIC COMPOSITION

摘要

PROBLEM TO BE SOLVED: To lower the water-absorbing property of a hydraulic composition by adding dispersion type powder containing the water-soluble salt of a sulfonated formaldehyde condensation product. SOLUTION: A preferable sulfonated formaldehyde condensation product is sulfonated melamine-, naphthalene- and/or phenol-formaldehyde condensation product. The water-soluble salt of the condensation product is preferably an alkali metal salt and/or an alkaline earth metal salt. The processability and water absorbability of the hydraulic composition can be adjusted by the content of the sulfonated formaldehyde condensation product in the dispersion type powder. The condensation product is preferably used in an amount of 5 to 20 pts.wt. per 100 pts.wt. of a film-forming polymer contained in the dispersion type powder. The film-forming polymer is especially preferably a copolymer obtained from vinyl acetate and vinyl 10-versatate.