Patent ID: 8329305

Claim:
A process for forming a coating film, the process comprising: (1) forming a reaction mixture comprising: (A) a silicon compound (A) of formula (1): Si(OR) 4 (1), wherein R is a C 1-5 alkyl group; (B) a silicon compound (B) of formula (2): CF 3 (CF 2 ) n CH 2 CH 2 Si(OR 1 ) 3 (2), wherein R 1 is a C 1-5 alkyl group, and n is an integer of from 0 to 12; (C) a silicon compound (C) of formula (3): H 2 NCONH(CH 2 ) m Si(OR 2 ) 3 (3), wherein R 2 is a C 1-5 alkyl group, and m is an integer of from 1 to 5; (D) an alcohol (D) of formula (4): R 3 CH 2 OH (4), wherein R 3 is a hydrogen atom or a C 1-12 alkyl group, such that the alkyl group is optionally substituted with one or more substituents of the same or different types selected from the group consisting of a C 1-3 alkyl group, a C 1-3 hydroxyalkyl group, a C 2-6 alkoxyalkyl group, a C 2-6 hydroxyalkoxyalkyl group and a C 3-6 alkoxyalkoxyalkyl group; and (E) oxalic acid (E), wherein (i) a ratio of the silicon compound (B) per mol of the silicon compound (A) ranges from 0.05 to 0.43 mol, (ii) a ratio of the silicon compound (C) per mol of the silicon compound (A) ranges from 0.01 to 0.20 mol, (iii) a ratio of the alcohol (D) per mol of the total alkoxy groups contained in the silicon compounds (A), (B) and (C) ranges from 0.5 to 100 mol, and (iv) a ratio of the oxalic acid (E) per mol of the total alkoxy groups contained in the silicon compounds (A), (B) and (C) ranges from 0.2 to 2 mol; and (2) heating the reaction mixture at a temperature ranging from 40 to 180° C. until the total amount of the silicon compounds (A), (B) and (C) remaining in the reaction mixture reaches at most 5 mol %, while maintaining a SiO 2 concentration ranging from 0.5 to 10 wt % as calculated from silicon atoms in the reaction mixture and in the absence of water, to form a polysiloxane; (3) forming a solution of the polysiloxane; (4) applying a coating fluid comprising the polysiloxane solution to a substrate surface to form a coating; (5) drying the coating at a temperature ranging from 40 to 100° C.; and (6) aging the coating at a temperature of from 40 to 100° C. for curing, to form a coating film having a refractive index of from 1.28 to 1.41 and a contact angle with water ranging from 90° to 115°, as adhered to the substrate surface.