Perfluoropolyether-organopolysiloxane copolymer and a surface treatment composition comprising the same

1. A surface treatment composition consisting essentially of a perfluoropolyether-polyorganosiloxane copolymer and/or a partial condensate of hydrolyzates thereof;

a solvent; and

optionally 0.01 to 5 parts by weight of a hydrolysis and condensation catalyst selected from the group consisting of organic tin compounds and organic titanium compounds, per 100 parts by weight of the perfluoropolyether-polyorganosiloxane copolymer and/or the partial condensate of hydrolyzates thereof;

wherein a concentration of the perfluoropolyether-polyorganosiloxane copolymer and/or the partial condensate of hydrolyzates thereof is in the range of from 0.01 to 50 wt %,

wherein the perfluoropolyether-polyorganosiloxane copolymer comprising at least one perfluoropolyether block, at least one polyorganosiloxane block which may have a silalkylene group, and two monovalent groups represented by the following formula (1), each one at both ends of the copolymer,

wherein X is a hydrolyzable group, R 1 is an alkyl group having 1 to 4 carbon atoms or a phenyl group, y is an integer of from 1 to 5, and a is an integer of 2 or 3,

said copolymer having a number average molecular weight, reduced to polystyrene, of from 7,000 to 25,000;

wherein a backbone of the perfluoropolyether-polyorganosiloxane copolymer is represented by the following formula (2)

—(Rf-Q) h -(W-Q-Rf-Q) g -W-(Q-Rf) i —  (2)

wherein Rf represents the perfluoropolyether block, W represents the linear polyorganosiloxane block, Q is a C 2-12 divalent connecting group which may have one or more oxygen and/or nitrogen atom, g is an integer of from 0 to 2, and h and i each are integers of 0 or 1; and

wherein silicon atoms are contained in an amount of from 3 to 30 wt %, based on a weight of the perfluoropolyether-polyorganosiloxane copolymer.

2. The surface treatment composition according to claim 1 , wherein the composition contains said hydrolysis and condensation catalyst.

3. The surface treatment composition according to claim 1 , wherein the solvent is one or more selected from the group consisting of fluorine-modified aliphatic hydrocarbon solvents, fluorine-modified aromatic hydrocarbon solvents, fluorine-modified ether solvents, fluorine-modified alkylamine solvents, hydrocarbon solvents, and ketone solvents.

4. The surface treatment composition according to claim 1 , wherein the backbone is represented by the following formula (2-1)

—Rf-Q-W-Q-Rf—  (2-1)

wherein Rf, W, and Q are as defined in claim 1 .

5. The surface treatment composition according to claim 1 , wherein the backbone is represented by the following formula (2-2)

—W-Q-Rf-Q-W—  (2-2)

wherein Rf, W, and Q are as defined in claim 1 .

6. The surface treatment composition according to claim 1 , wherein the backbone is represented by the formula (2) with both h and i being 1 or both h and i being 0, and the monovalent group represented by the formula (1) is bound to a carbon atom in the perfluoropolyether block or to a silicon atom of the polyorganosiloxane block via a divalent group represented by the following formula

-Q(Z) k -

wherein Q is the divalent connecting group as defined above, Z is a divalent polyorganosiloxane residue which has 1 to 8 silicon atoms and may have a silalkylene group, k is an integer of 0 or 1, and the monovalent group represented by the formula (1) is bound to a silicon atom of Z when k is 1.

7. The surface treatment composition according to claim 1 , wherein the perfluoropolyether block is represented by the following formula (3), (4), or (5):

wherein Y may be the same with or different from each other and is a fluorine atom or a CF 3 group, r is an integer of from 2 to 6, d is an integer of from 1 to 3, each of m and n is an integer of from 0 to 200 with m+n ranging from 2 to 200, s is an integer of from 0 to 6, and the repeating units may be bonded randomly;

C d F 2d (CF 2 CF 2 CF 2 O) l C d F 2d —  (4)

wherein 1 is an integer of from 1 to 200 and d is an integer of from 1 to 3; and

wherein Y is a fluorine atom or a CF 3 group, d is an integer of from 1 to 3, each of m and n is an integer of from 0 to 200 with m+n ranging from 2 to 200, and the repeating units may be bonded randomly.

8. The surface treatment composition according to claim 1 , wherein the perfluoropolyether block is represented by the following general formula (6)

—CF 2 (OC 2 F 4 ) m (OCF 2 ) n OCF 2 —  (6)

wherein m is an integer of from 0 to 50, n is an integer of from 0 to 50 with m+n ranging from 2 to 60.

9. The surface treatment composition according to claim 1 , wherein the polyorganosiloxane block is a linear polyorganosiloxane block having 2 to 150 repeating units represented by the following formula (7)

wherein R 2 may be the same with or different from each other and is an alkyl group having 1 to 4 carbon atoms or a phenyl group.

10. The surface treatment composition according to claim 1 , wherein Q is represented by the following formula:

—CH 2 OCH 2 CH 2 CH 2 —.

11. The surface treatment composition according to claim 1 , wherein X is an alkoxy group having 1 to 10 carbon atoms.

12. The surface treatment composition according to claim 1 , wherein the backbone is represented by the following formula (2-3)

—Rf-Q-W-Q-Rf-Q-W-Q-Rf—  (2-3)

wherein Rf, W, and Q are as defined in claim 1 .

13. The surface treatment composition according to claim 1 , wherein the composition does not contain said hydrolysis and condensation catalyst.