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Aqueous silane coupling agent solution for use as a sealant primer
Patent number: 5363994
Assignee: Tremco, Inc. (Beachwood, OH)
Inventors: Barry D. Angeline (Cleveland Heights, OH)
An aqueous primer composition for facilitating and promoting good adhesion across an interface between a nonporous substrate and a polymeric coating composition contains from about 0.05 to about 0.3 parts by weight of an amimopropylsilane or a mercaptopropylsilane per 100 parts by weight of water and, optionally to facilitate adhesion under wet conditions, up to about 0.4 parts by weight of a hydrophobic silane per 100 parts by weight of water and aminopropylsilane or mercaptopropylsilane. The primer composition is nontoxic, nonflammable and free or substantially free of any environmentally undesirable volatile organic components. In accordance with a preferred aspect of the invention, the primer composition includes an effective amount of a conventional surfactant sufficient to uniformly wet the surface of the substrate to enable uniform dispersion of the silane coupling agent over the surface. The primer composition is also preferably adjusted to a pH of from about 2.0 to about 5.5 to inhibit condensation or oligomerization of the silane coupling agent and thereby increase the useful shelf-life of the composition.