| abstract |
(57) [Problem] To provide a polymer having good viscosity or cement stability and not inhibiting cement hardening in cement applications. SOLUTION: Polyvinyl having 0 to 5.0 mol% of vinyl acetate units, 75 to 95 mol% of vinyl alcohol units, and 0.1 to 20 mol% of acetal units derived from aldehyde having 3 to 7 C atoms. A polyvinyl acetal-graft polymer in the form of an aqueous dispersion or a water-redispersible powder, based on an emulsion polymer or a suspension polymer, grafted with an acetal. |