To obtain a composition capable of easily controlling the set-retarding part and the set-retardation extent of the surface of a hydraulic mixture and giving a film having excellent handleability by using a polymer having a specific acid value acid value as a main component.
This composition for the production of a film for covering a surface of an uncured hydraulic mixture to retard the setting of the covered surface part is composed mainly of a polymer having an acid value of 60-600 mgKOH/g, preferably 100-200mgKOH/g. The polymer is preferably a copolymer of 10-30wt.% of an α,β-unsaturated carboxylic acid and other unsaturated monomers. The α,β-unsaturated carboxylic acid is preferably (meth)acrylic acid and 30wt.% of the other unsaturated monomer is preferably an ester of a 1-18C monohydric alcohol and (meth)acrylic acid. The glass transition point of the polymer is preferably 20-80°C.
MURAKAMI YOHEI
MINAMI KENJI
NIPPON CATALYTIC CHEM IND