Priming compositions for a base of cement mortar or concrete

摘要

The invention provides an improved method for priming the surface of a cement mortar or concrete base whereby the adhesive bonding strength of the overcoat finishing with a cement mortar or paste as well as the waterproofing effect of the overcoat layer can be greatly improved by use of a novel aqueous priming composition. The priming composition contains, as an essential ingredient as dissolved in an aqueous medium, a modified polyvinyl alcohol characteristic in the side chains etherified with long-chain alkyl groups such as lauryl and stearyl in a limited mole fraction. The priming composition may also contain an emulsion of a synthetic resin mainly composed of vinyl acetate. The effectiveness of the modified polyvinyl alcohol is so outstanding that the inventive priming composition may contain only 1% by weight or more of the modified polyvinyl alcohol based on the total solid content, the balance being the synthetic resin dispersed as the emulsion.