| 摘要 |
In a mortar comprising an inorganic binder, water and a sulphonated phenol condensation product modifier therefor, the improvement wherein said condensation product comprises a formaldehyde condensation product of a phenol wherein at least about 40% of the phenolic OH groups are etherified with an alkylating agent, the condensation product being present in about 0.05 to 5% by weight of the binder. Advantageously the condensation product is of the formula <IMAGE> (I) in which R is H, C1-6-alkyl, C1-12-aralkyl, C1-4-monohydroxy or dihydroxy alkyl, of C3-4-hydroxy chloralkyl, less than 40% of the R groups being H, X is H, CH2-SO3M, CH2OH, CH2-R' or NR'4, at least about half the X groups being CH2-SO3M, M is Na, K, Ca/2 or Mg/2, R' is H, C1-4-alkyl, C2-4-hydroxy alkyl, or another structural unit of the formula (I) and n is at least 3. Thereby the mortar is rendered more plastic and dense while retaining its setting characteristics.
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