Transparent film

A transparent film comprising:

• a polysiloxane backbone;
• a trialkylsilyl containing molecular chain bonded to a part of silicon atoms forming the polysiloxane backbone,
• wherein the number of elements forming the trialkylsilyl containing molecular chain is not less than 50,
• alkyl groups in the trialkylsilyl containing molecular chain may be replaced by fluoroalkyl groups;
• and
• a unit including a metal atom and a group bonded to the metal atom selected from a siloxane containing group and hydroxy group, wherein the metal atom is selected from trivalent and tetravalent metal atoms capable of forming a metal alkoxide, the number of elements in the siloxane containing group is smaller than the number of elements in the molecular chain of the trialkylsilyl containing molecular chain, and the unit is bonded to the polysiloxane backbone at a position of the metal atom,
• wherein the difference in the number of elements between the trialkylsilyl containing molecular chain and the siloxane containing group is not less than 20, and
• the transparent film satisfies a relationship represented by a formula below:
• (Bz1−A1)/A1×100(%)≥−9(%)
• provided that A1 is an initial contact angle of a liquid droplet on the transparent film, and Bz1 is a contact angle of the liquid droplet on the transparent film irradiated by a mercury lamp having an emission line in a region of not more than 300 nm with an intensity at an irradiated surface of 200±10 mW/cm2 at a temperature of 20 to 40° C. and a humidity of 30 to 75% for 4 hours under an air atmosphere.

A coating composition comprising an organosilicon compound (a) and a metal compound (b),

• wherein the organosilicon compound (a) comprises at least one trialkylsilyl containing molecular chain and at least one hydrolyzable group bonded to a silicon atom, and
• the metal compound (b) is a compound represented by a formula (II-1) below:
• wherein M represents a trivalent or tetravalent metal atom capable of forming a metal alkoxide;
• each of Ab1 independently represents a hydrolyzable group;
• Zb2 represents a siloxane containing group, a hydrocarbon chain-containing group or a hydrolyzable group;
• Rb2 represents a siloxane containing group, a hydrocarbon chain-containing group or a hydrolyzable group, Rb2 and Zb2 may be the same or different when Rb2 and Zb2 represent a siloxane containing group or a hydrocarbon chain-containing group, and Rb2 and Ab1 may be the same or different when Zb2 represents a hydrolyzable group, and Rb2 and Zb2 may be the same or different among a plurality of formulae (II-1);
• k represents an integer of 0 or 1 depending on M;
• and
• wherein the siloxane containing group comprises elements in a number smaller than the number of elements forming the trialkylsilyl containing molecular chain in the organosilicon compound (a) when Rb2 represents a siloxane containing group,
• wherein the difference in the number of elements between the trialkylsilyl containing molecular chain and the siloxane containing group is not less than 20.

A compound represented by a formula (I-I) below:

• wherein each of Aa1 independently represents a hydrolyzable group;
• Za2 represents a trialkylsilyl containing molecular chain, a hydrocarbon chain-containing group, a siloxane containing group or a hydrolyzable group, and Za2 and Aa1 may be the same or different when Za2 represents a hydrolyzable group, and Aa1 and Za2 may be the same or different among a plurality of formulae (I-I);
• each of Rs3 independently represents an alkyl group with a carbon number of not less than 1 and not more than 4;
• Rs4 represents a divalent hydrocarbon group with a carbon number of not less than 1 and not more than 10, and a methylene group (—CH2—) in Rs4 may be replaced by an oxygen atom;
• each of Rs5 independently represents an alkyl group with a carbon number of not less than 1 and not more than 4;
• m1 and n1 independently represent an integer of not less than 0;
• the number of elements forming —(O—Si(Rs3)2)n1—(Rs4)m1—Si(O—Si(Rs5)3)3 is not less than 50;
• provided that occurrence order of the repeating units parenthesized with the subscripts of n1 and m1 is arbitrary in the formula;
• and
• the compound satisfies at least one of the following requirements (i) and (ii):
• (i) m1 represents an integer not less than 3, Rs4 represents methylene group (—CH2—) and (Rs4)m1 contains at least one —CH2—O—CH2— moiety, and
• (ii) n1 represents an integer of not less than 1.