For coat low the optical multilayer film null general expression which consists of the index of refraction constituent

摘要

PROBLEM TO BE SOLVED: To provide a composition having a low refractive index, excellent in hardness, scratch resistance, adhesion to a substrate, and antifouling property, and provide an optical multilayer film made of the composition, inexpensive and excellent in productivity. SOLUTION: This composition comprises the following substances as main components, silicon alkoxide represented by the general formula (A): Si(OR)4 (wherein R is alkyl group) and its hydrolysate, an organosilicon compound represented by the formula (B): R'XSi(OR)4-X (wherein R is an alkyl group; R' is a functional group having at its terminals a polymerizable unsaturated bond such as a vinyl group, an acryloyl group, a methacryloyl group, etc.; x is a number of substitutions satisfying the range of 0x4) and its hydrolysate. The optical multilayer film is made by using this composition.