COATING FILM HAVING LOW REFRACTIVE INDEX AND LARGE WATER CONTACT ANGLE

摘要

Disclosed is a method for forming a modified coating film on a base. Specifically disclosed is a coating film which is formed on the surface of a base in an appressed manner and has a refractive index of 1.28-1.38 and a water contact angle of 90-115 degrees. The coating film having a refractive index of 1.28-1.38 and a water contact angle of 90-115 degrees is formed as follows: a solution of a polysiloxane is formed by heating a reaction mixture at 50-180°C without the presence of water which reaction mixture contains a silicon compound (A) expressed as Si(OR) 4, a silicon compound (B) expressed as (R1O)3 SiCH2CH2(CF2)nCH2CH2 Si(OR1)3, an alcohol (C) expressed as R3CH 2OH and an oxalic acid (D) at a specific ratio; then a coating liquid containing the solution is applied to the surface of a base; and the coating film is heat cured at 80-450°C so that it is closely adhered to the base surface. Also disclosed are a method for forming such a coating film and a method for producing such a coating liquid.