Compositions comprising a tin-based catalyst and titanium dioxide for moisture cure of silane-functionalized ethylenic polymers
The process of curing a silane-functionalized ethylenic polymer using a tin-based catalyst, e.g., dibutyltin dilaurate, is accelerated by the addition of a titanium (IV) oxide.
1. A catalyst composition for promoting the cure of a silane-functionalized ethylenic polymer, the catalyst composition comprising
(1) a tin-based catalyst, and
(2) a titanium (IV) oxide selected from the group consisting of
(i) titanium dioxide (TiO 2 ); and
(ii) tetraisopropyl titanate;
with the proviso that when the titanium (IV) oxide is tetraisopropyl titanate, catalyst composition has a tin-based catalyst to tetraisopropyl titanate weight percent ratio from 0.5:1 to 1.0:0.5, based on the total weight of the catalyst composition.
2. The catalyst composition of claim 1 in which the tin-based catalyst is at least one of dibutyl tin dilaurate (DBTDL), dimethyl hydroxy tin oleate, dioctyl tin maleate, di-n-butyl tin maleate, dibutyl tin diacetate, dibutyl tin dioctoate, stannous acetate and stannous octoate.
3. The catalyst composition of claim 2 wherein the titanium (IV) oxide is titanium dioxide (TiO 2 ).
4. The catalyst composition of claim 2 wherein the titanium (IV) oxide is tetraisopropyl titanate.
5. A masterbatch comprising (A) the catalyst composition of claim 1 , and (B) a carrier resin.
6. A process for curing a silane-functionalized ethylenic polymer, the process comprising the steps of (1) forming a polymer composition by mixing the silane-functionalized ethylenic polymer and the catalyst composition of claim 1 , and (2) subjecting the polymer composition to curing conditions.
7. The process of claim 6 in which the catalyst composition is in the form of a masterbatch.
8. The process of claim 6 in which the silane functionality of the silane functionalized ethylenic polymer is a derivative of a vinyl trialkoxy silane.
9. The process of claim 6 in which the curing conditions are an elevated temperature and elevated humidity.