Composition for forming water repellent film, water repellent film, substrate with water repellent film, and article

1. A composition for forming a water repellent film consisting of:

a compound represented by Formula (1) below;

a compound represented by Formula (2) below and having a number average molecular weight of 3000 or more;

optionally a solvent; and

optionally other components selected from the group consisting of a dye, a pigment, an antifouling material, a curing catalyst, and a resin,

wherein a molar ratio of a group SiR 1 p X 1 3-p in the compound represented by Formula (1) and a group SiR 2 r X 2 3-r in the compound represented by Formula (2) and having the number average molecular weight of 3000 or more ([the number of moles of SiR 1 p X 1 3-p in the compound represented by Formula (1)]/the number of moles of SiR 1 p X 1 3-p in the compound represented by Formula (2) and having the number average molecular weight of 3000 or more]) is 1.5 to 20, and a molar ratio of the compound represented by Formula (1) and the compound represented by Formula (2) and having the number average molecular weight of 3000 or more ([the number of moles of the compound represented by Formula (1)]/[the number of moles of the compound represented by Formula (2) and having the number average molecular weight of 3000 or more]) is 2 to 40,

R f1 -Q 1 -SiR 1 p X 1 3-p   Formula. (1)

where, R f1 is a group C k F 2k+1 , where k is an integer of 1 to 8,

Q 1 is a bivalent hydrocarbon group having 1 to 6 carbon atoms,

R 1 's are each independently a monovalent hydrocarbon group having 1 to 6 carbon atoms,

X 1 's are each independently a hydroxyl group or a hydrolyzable group, and

p is an integer of 0 to 2,

[A] b1 Q 2 [B] b2   Formula. (2)

where, Q 2 is a linking group having a valency of (b1+b2),

A is a group represented by R f3 —O—R f2 —, where R f2 is a poly(oxyfluoroalkylene) chain, and R f3 is a perfluoroalkyl group,

B is a monovalent group having one —R 12 —(SiR 2 r —X 2 3-r ), where R 12 is a hydrocarbon group having 2 to 10 carbon atoms that optionally has an ether oxygen atom between the carbon-carbon atoms or at an end opposite to a side bonded with Si or optionally has —NH— between the carbon-carbon atoms, R 2 's are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 6 carbon atoms, the hydrocarbon group optionally containing a substituent, X 2 's are each independently a hydroxyl group or a hydrolyzable group, and r is an integer of 0 to 2, and including no fluorine atom,

Q 2 and B include no cyclic siloxane structure,

b1 is an integer of 1 to 3,

b2 is an integer of 2 to 9, and

in a case where b1 is 2 or more, b1 pieces of A may be identical or different, and b2 pieces of B may be identical or different.

2. The composition for forming a water repellent film according to claim 1 , wherein R f2 in Formula (2) is a group represented by —(C a F 2a O) n —-, where a is an integer of 1 to 6, n is an integer of 2 or more, and the —C a F 2a O— units may be identical or different.

3. The composition for forming a water repellent film according to claim 1 , wherein R f2 in Formula (2) is a group represented by a group —CF 2 CF 2 CF 2 CF 2 CF 2 CF 2 O) n1 —(CF 2 CF 2 CF 2 CF 2 CF 2 O) n2 —(CF 2 CF 2 CF 2 CF 2 O) n3 —(CF 2 CF 2 CF 2 O) n4 —(CF(CF 3 )CF 2 O) n5 —(CF 2 CF 2 O) n6 —(CF 2 O) n7 —, where n1, n2, n3, n4, n5, n6, and n7 are each independently an integer of 0 or more, the sum of n1, n2, n3, n4, n5, n6, and n7 is 2 or more, and the repeating units may exist in block, alternately, or randomly.

4. A water repellent film formed by using the composition for forming a water repellent film according to claim 1 .

5. A substrate with a water repellent film comprising a substrate and the water repellent film according to claim 4 on at least part of the substrate.

6. The substrate with a water repellent film according to claim 5 comprising a base layer between the substrate and the water repellent film.

7. The substrate with a water repellent film according to claim 5 , wherein the substrate is glass or sapphire.

8. An article comprising the substrate with a water repellent film according to claim 5 .