Primer-less abrasion coating for organic glass articles
View Patent ↗The present invention provides a method for improving adhesion of polyorganosiloxane to plastic, such as polycarbonate substrates. In a preferred embodiment, a tertiary amine is added to a polyorganosiloxane coating composition to achieve an improved abrasion coating.
1. A coating composition for use on a primer-less optical article comprising:
a. a glycidyl- or glycidoxy-functional silane of the formula:
wherein R 1 , R 2 , and R 3 are independently selected from group consisting of hydrogen, aliphatic groups and aromatic groups which complete a siloxane on the silicon (Si) atom;
n is an integer from 1 to 4, and;
EP represents a glycidyl (e.g., glycidoxy) group;
b. a tetraalkoxylsilane of the formula:
wherein R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of hydrogen, aliphatic groups and aromatic groups which complete a siloxane on the silicon (Si) atom; and
c. a tertiary amine comprising triethanolomine the amount of glycidyl- or glycidoxy-functional silane is from about 30 to 70% by weight of the total coating solid, the level of tetraalkoxysilane is from about 30 to 70% by weight of the total coating solid and the total level of triethanolamine is from about 0.1 to 5% by weight of the total coating solid.
2. The coating composition of claim 1 further comprising a multi-functional epoxy compound.
3. The coating composition of claim 1 further comprising multi-functional epoxy colloidal silica.
4. The coating composition of claim 1 wherein an effective amount of one or more solvents is added to form a coating solution having a solid level from about 1 to 40% by Weight.
5. The coating composition of claim 1 wherein the amount of said triethanolamine added to said coating composition is between about 0.05% and 3.0% of the total coating by weight.
6. The coating composition of claim 1 wherein an coating composition is disposed on at least one surface of an organic surface of an article.
7. The coating composition of claim 6 wherein organic glass surface of the article is a substrate comprising a polymeric ophthalmic lens.
8. The coating composition of claim 7 wherein the polymeric opthalmic lens comprises a polycarbonate ophthalmic lens.
9. The coating composition of claim 1 wherein a Bayer ratio of the coating is higher than 4.0.
10. The coating composition of claim wherein the glycidyl- or glycidoxy-functional silane and tetraalkoxysilane are mixed with solvents and water.
11. The coating composition of claim 1 wherein R 1 , R 2 and R 3 are independently selected from the group consisting of alkyl groups, benzyl groups or phenyl groups.
12. The coating composition of claim 1 wherein R 1 , R 2 and R 3 are independently selected from the group consisting of unsubstituted alkyl groups.
13. The coating composition of claim 1 wherein R 1 , R 2 and R 3 of the glycidyl- or glycidoxy-functional silane of the formula are independently selected from the group consisting of alkyl, benzyl and phenyl groups; and R 1 , R 2 , R 3 , and R 4 of the tetraalkoxysilane of the formula are independently selected from the group consisting of alkyl, benzyl, and phenyl groups.
14. The coating composition of claim 1 wherein R 1 , R 2 and R 3 of the glycidyl- or glycidoxy-functional silane of the formula are independently selected from the group consisting of unsubstituted alkyl groups, and R 1 , R 2 , R 3 , and R 4 of the tetraalkoxysilane of the formula are independently selected from the group consisting of unsubstituted alkyl groups.