Patent ID: 10222511

Abstract:
The invention relates to an optical article comprising a substrate coated with an abrasion and scratch resistant coating composed of a lower layer and an upper layer that do adhere to each other, the upper layer and the lower layer being layers of cured upper and lower layer compositions, said upper layer composition comprising at least one organosilane, or a hydrolyzate thereof, of formula RnYmSi(X)4-n-m and at least one compound, or a hydrolyzate thereof, of formula M(Z)x, the following ratio being lower than 2.3: said lower layer composition comprising at least one organosilane, or a hydrolyzate thereof, of formula R′n′Y′m′Si(X′)4-n′-m′ and, optionally, at least one compound, or a hydrolyzate thereof, of formula M′(Z′)y, the following ratio being higher than 2.3:  In the hereabove formulas, M and M′ are metals or metalloids of valences x and y, at least equal to 4, R and R′ groups are monovalent organic groups that are bound to silicon through a carbon atom and that contain at least one epoxy function, X, X′, Z and Z′ groups are hydrolyzable groups, Y and Y′ are monovalent organic groups that are bound to silicon through a carbon atom, n, m, n′ and m′ being integers such that n and n′=1 or 2 with n+m and n′+m′=1 or 2.