Fluorine-containing surface treating agent and an article surface-treated therewith

A surface treating agent composition comprising:

• a perfluoropolyether group-containing polyorganosiloxane represented by the following formula (1) and/or
• a partial hydrolysis condensate thereof,
• Ak(R)nZ-Q-Rf-Q-Z(R)nAk (1)
• wherein Rf is a divalent perfluoropolyether group;
• Q is a divalent group linking Rf with Z;
• Z is a polyorganosiloxane group having at least three siloxane bonds with its valency being trivalent to undecavalent;
• R is a monovalent organic group having 8 to 40 carbon atoms, n is an integer of from 1 to 8;
• A is a group represented by the following formula (2);
• and k is an integer of from 1 to 9, provided that n+k=(the valency of Z−1),
• wherein R′ is an alkyl group having 1 to 4 carbon atoms or a phenyl group;
• X is a hydrolysable group, a is 2 or 3;
• and b is an integer of from 2 to 10.

An article having, on the surface thereof, a cured coating made from a perfluoropolyether group-containing polyorganosiloxane represented by the following formula (1) and/or a partial hydrolysis condensate thereof,

• Ak(R)nZ-Q-Rf-Q-Z(R)nAk (1)
• wherein Rf is a divalent perfluoropolyether group;
• Q is a divalent group linking Rf with Z;
• Z is a polyorganosiloxane group having at least three siloxane bonds with its valency being trivalent to undecavalent;
• R is a monovalent organic group having 8 to 40 carbon atoms, n is an integer of from 1 to 8;
• A is a group represented by the following formula (2);
• and k is an integer of from 1 to 9, provided that n+k=(the valency of Z−1),
• wherein R′ is an alkyl group having 1 to 4 carbon atoms or a phenyl group;
• X is a hydrolysable group, a is 2 or 3;
• and b is an integer of from 2 to 10.