Coating composition and coating film

A coating composition comprising a silicon atom-containing resin,

• wherein
• the silicon atom-containing resin includes:
• a constituent unit (A) derived from a monomer (a) selected from the group consisting of a monomer (a1) represented by a formula (I′) below, and a monomer (a3) represented by a formula (III′) below;
• a constituent unit (B) derived from a monomer (b) having a triorganosilyloxycarbonyl group represented by a formula (VII′) below;
• and
• a constituent unit (C) derived from a monomer (c) other than the monomer (a) and the monomer (b),
• the monomer (a) has a molecular weight of greater than or equal to 3000 and less than or equal to 12000,
• the monomer (c) is a monomer having a homopolymer solubility parameter SP of greater than or equal to 8.0 and less than or equal to 9.5 and having no cyclic structure,
• a content of the constituent unit (A) is greater than or equal to 11% by mass and less than or equal to 60% by mass in all constituent units contained in the silicon atom-containing resin,
• a content of the constituent unit (B) is greater than or equal to 5% by mass and less than or equal to 40% by mass in all constituent units contained in the silicon atom-containing resin,
• a content of the constituent unit (C) is greater than or equal to 5% by mass and less than or equal to 45% by mass in all constituent units contained in the silicon atom-containing resin,
• the monomer (c) is a (meth)acrylic acid alkyl ester represented by
• CH2═C(RA)(COORB)
• RA is a hydrogen atom or a methyl group, and RB is a chain alkyl group having 3 to 8 carbon atoms,
• in the formula (I′), a and b each independently represent an integer of 2 to 5, m represents an integer of 0, n represents an integer of 3 to 270;
• R1 to R5 each independently represent a 1 to 6 carbon alkyl group, and R31 represents a hydrogen atom or a methyl group;
• in the formula (III′), e, f, g, and h each independently represent an integer of 2 to 5, q and s each independently represent an integer of 0, r represents an integer of 3 to 270;
• R9 to R12 each independently represent a 1 to 6 carbon alkyl group, and R33 and R34 each independently represent a hydrogen atom or a methyl group;
• and
• in the formula (VII′), R43 represents a hydrogen atom or a methyl group, and R40, R41 and R42 each represent an isopropyl group, and
• wherein a content of the silicon atom-containing resin is greater than or equal to 35% by mass and less than or equal to 99% by mass in a solid content contained in the coating composition.