Low VOC aqueous coating composition
AssigneeRohm and Haas Company
InventorsAsare Nkansah, Stewart Orlyn Williams, Richard Foster Merritt
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Abstract
An aqueous coating composition having low VOC is provided. The invention provides excellent hardness and resistance properties in films formed from binders having glass transition temperatures below ambient temperature. The improvement in film properties comes from the binding of functionalized polyvinyl alcohol to a complementary functionalized latex binder. The low VOC compositions of this invention are useful for a variety of coatings including paints, stains, varnishes, mastics and adhesives.
Claims7
An aqueous, film-forming coating composition comprising at least one aqueous latex polymer binder covalently grafted with polyvinyl alcohol;
- said aqueous latex polymer binder having a glass transition temperature (Tg) in the range of from -35.degree. C. to +30.degree. C. and having a first reactable group selected from the group consisting of beta-ketoester, aldehyde, amine, anhydride, isocyanate, epoxy, and hydrazide;
- said polyvinyl alcohol having a second reactable group selected from the group consisting of beta-ketoester, aldehyde, amine, anhydride, isocyanate, epoxy, and hydrazide which is complementary to the first reactable group in the aqueous latex polymer binder;
- said coating composition having less than two percent volatile organic compounds based on the dry weight of the polymer binder.
A method for providing increased hardness and resistance properties of a film formed from an aqueous coating composition comprising:
- a) blending at least one aqueous latex polymer binder with polyvinyl alcohol;
- said aqueous latex polymer binder having a glass transition temperature (Tg) in the range of from -35.degree. C. to +30.degree. C. and having a first reactable group selected from the group consisting of beta-ketoester, aldehyde, amine, anhydride, isocyanate, epoxy, and hydrazide said polyvinyl alcohol having a second reactable group selected from the group consisting of beta-ketoester, aldehyde, amine, anhydride, isocyanate, epoxy, and hydrazide which is complementary to the first reactable group in the aqueous latex polymer binder wherein said aqueous coating composition contains less than two percent volatile organic compounds based on the dry weight of the polymer binder;
- b) applying said coating composition to a substrate;
- and
- c) drying said coating composition to form a film.
Dependencies are inferred from the claim text.