Primer composition

#The present invention relates to a primer composition. More specifically, it relates to a primer composition which gives a cured film having a high refractive index and impact resistance.

#Being susceptible to damage, most plastic lenses are provided with hard coating(s) by applying a silicon-containing primer or other hard-coating primer to their surface(s) and curing the primer with ultraviolet light.

#Further, plastic lenses are sometimes coated with anti-reflection films formed by vapor deposition of an inorganic substance on their surface for preventing surface reflection. However, these lenses have low impact resistance and have a defect that they break in a falling ball test (FDA standards, U.S.A.).

#The present invention will be explained in detail hereinafter, while the present invention shall not be limited by these Examples.

#Synthesis of blocked isocyanate

#Xylylene diisocyanate (TAKENATE 500, trade name, supplied by Takeda Chemicals Industries, Ltd.) was dissolved in cyclohexanone, and while the mixture was stirred at 40.degree. C., a small amount of dibutyltin dilaurate as a catalyst was added thereto. Then, while an absorption caused by NCO was measured by IR measurement, butanoneoxime was added little by little until the absorption ascribed to NCO was not found. The resultant solution was adjusted so as to have a non-volatile content of 70%, and this solution was used as Liquid A.