| abstract |
The present invention relates to acid and alkali resistant compositions, methods for their preparation and use thereof in the manufacture of articles, and articles comprising a substrate coated or impregnated therewith, and methods and uses of the articles. The composition contains: at least one aqueous polyurethane dispersion having carboxyl groups; at least one crosslinking agent having an isocyanate-reactive group; at least one crosslinking agent having a carboxyl reactive group; and optionally additives; wherein the amount of carboxyl groups in the aqueous polyurethane dispersion is greater than 0.05% by weight based on 100% by weight of the amount of the aqueous polyurethane dispersion; the amount of the crosslinking agent having an isocyanate-reactive group is 0.2% by weight-10% by weight based on 100% by weight of the composition; The molar ratio of carboxyl reactive groups to carboxyl groups in the composition is greater than 0.5. The film formed from the composition of the present invention has excellent acid resistance and alkali resistance. The product obtained by treatment with the composition of the present invention has a flat appearance and excellent tactile feel. |