In recent years, attention has been drawn to plastic lenses as materials For eye-glasses since they have light weights as compared with inorganic glasses, are excellent in the impact resistance and are capable of being easily dyed. For these reasons, various plastic lenses having a high index of refraction and a low chromatic aberration have been proposed.
Generally, plastic lenses have a disadvantage in that they are easily scratched and, therefore, a silicone type hard coat film is usually provided on the surface of the lenses. In some cases, lenses having a reflection preventing film formed by vapor-deposition of an inorganic substance for the purpose of preventing flicker and ghost by reflection from the surface of the lens are put into practical use.
However, a plastic lens having provided thereon a hard coat layer only and a plastic lens having provided thereon both a hard coat and a reflection preventing film have also a disadvantage in that they are inferior in the impact resistance as compared with the plastic lens having no such films, and a means for solving this problem has been studied from the various viewpoints. For example, a plastic lens having a primer layer between the lens base material and the hard coat layer for the purpose of improving the impact resistance has been proposed as described in Japanese Patent Publication (Kokai) No. Sho 61-251801.
However, since the above-proposed lens has a relatively soft primer layer comprising an acryl-styrene type emulsion resin, another problem has arisen in that such a soft primer layer adversely affects the scratch resistance of the hard coat layer itself and, thus, the lens is inferior in the scratch resistance as compared with the plastic lens having no primer layer.
Accordingly, an object of the present invention is to provide a plastic lens which is excellent in the scratch resistance even though it has a primer layer, and which is excellent in the impact resistance even though it has a hard coat film or a hard coat film and a reflection preventing film.
USPTO Backgrounds
USPTO Backgrounds