| 摘要 |
PROBLEM TO BE SOLVED: To obtain an additive excellent in finishing properties by a plasterer, by including a polysaccharide derivative prepared by substituting the hydrogen atoms of the hydroxyl groups of a polysaccharide or its alkylated derivative with a hydrophobic substituent group containing a hydrocarbon chain as a partial structure and a hydrophilic substituent group containing a group selected from a sulfonic group, etc., as a partial structure. SOLUTION: This additive for a mortar contains a polysaccharide derivative obtained by substituting hydrogen atoms of a part or the whole hydroxyl groups of a polysaccharide or its alkylated or hydroxy alkylated derivative with (A) a hydrophobic substituent group containing a 8-40C hydrocarbon chain as a partial structure and (B) an ionic hydrophilic substituent group containing one or more groups selected from the group consisting of a sulfonic group, a carboxyl group, a sulfate group and their salts as a partial structure. The admixture is mixed with a cement material and a fine aggregate to give a mortar composition. The degree of substitution of the substituent A is 0.0001-1 based on the constituent monosaccharide residue and that of the substituent B is 0.001-2. |
