WATER REPELLENT COATING FILM HAVING LOW REFRACTIVE INDEX

摘要

Disclosed is a coating film with high hardness which is formed on the surface of a base in an appressed manner and has a refractive index of 1. 28-1.41 and a water contact angle of 90-115 degrees. Specifically disclosed is a coating film having a refractive index of 1.28-1.41 and a water contact angle of 90-115 degrees which is formed by preparing a reaction mixture containing a silicon compound (A) expressed as Si(OR) 4, a silicon compound (B) expressed as CF3(CF2)nCH2CH2Si(OR1)3, a silicon compound (C) expressed as H2NCONH(CH)mSi(OR2) 3, an alcohol (D) expressed as R3CH2OH, and an oxalic acid (E) at a specific ratio; forming a solution of a polysiloxane by heating the reaction mixture at 40-180°C without the presence of water; applying a coating liquid containing the solution to the surface of a base; and heat curing the coating film at 40-450°C so that the coating film 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.