| 摘要 |
The aqueous coating composition, which is particularly adaptable for use as a household floor polish or a temporary protective coating for various articles, contains a non-volatile, solid film former, such as an acrylic copolymer, dispersed in the aqueous phase or base, and a water-soluble, acid-base indicator, such as thymolphthalein, which is colored at a pH above a predetermined level and is colorless at a lower pH. Upon being applied on the surface of a substrate, a substantially colorless film is formed thereon upon the evaporation of the water and the color indicator becomes an integral part of the dried film. Upon the application of an aqueous alkaline cleaning or stripping solution having a pH above that required to effect a color change of the color indicator, (e.g., above about 11.6 when thymolphthalein is used), the film changes to a distinctive color (e.g., blue when thymolphthalein is used) so that one can readily observe whether the old film has been completely removed before the surface becomes dry.
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