Isocyanate-functionalized organosilanes as adhesion promoters in sealant and primer compositions

A method of sealing an optionally pre-coated substrate comprising

• (1) optionally applying a primer composition at least in portion onto a surface of an optionally pre-coated substrate to form a primer film at least in portion on said surface,
• (2) applying a sealant composition at least in portion onto a surface of an optionally pre-coated substrate in case optional step (1) is not performed or onto the primer film in case optional step (1) is performed,
• wherein the sealant composition is different from the primer composition optionally applied in step (1) and is obtained by mixing the components of a sealing system with each other, said sealing system being a two-component (2K) sealing system comprising two components (A) and (B) being separate from each other,
• wherein component (A) of the sealing system comprises at least one polymeric constituent (a1) comprising two or more thiol groups selected from the group consisting of polyether, polythioether, polysulfide, polythioether-sulfide constituents and mixtures thereof, and wherein component (B) of the sealing system comprises at least one constituent (b), which is suitable for hardening the sealant composition by at least partially inducing a chemical transformation of the two or more thiol groups of constituent (a1),
• wherein at least one organosilane constituent, which comprises
• (i) at least one hydrolyzable group X,
• (ii) at least one isocyanate group, and
• (iii) a spacer unit positioned between the at least one hydrolyzable group X and the at least one isocyanate group, wherein said spacer unit comprises at least one moiety MS, which comprises at least one sulfur atom,
• is at least present—when optional step (1) is not performed—as constituent (a2) in component (A) of the sealing system used for preparing the sealant composition applied in step (2) or is—when step (1) is performed—at least present as a constituent in the primer composition applied in step (1).