Silane compound containing perfluoro(poly)ether group

1. A perfluoro(poly)ether group containing silane compound of the formula (1):

(Rf-PFPE) α —X—(SiQ k Y 3-k ) β   (1)

wherein:

Rf represents, each independently at each occurrence, a C 1-16 alkyl which may be substituted by one or more fluorine atoms;

PFPE represents —(OC 4 F 8 ) a —(OC 3 F 6 ) b —(OC 2 F 4 ) c —(OCF 2 ) d —

wherein a, b, c and d are each independently an integer of 0 or more and 200 or less, the sum of a, b, c and d is 1 or more and the occurrence order of the respective repeating units in parentheses with the subscript a, b, c or d is not limited in the formula;

X represents, each independently at each occurrence, a 3-10 valent organic group;

Y represents, each independently at each occurrence, a hydrogen atom, a hydroxyl group, a hydrolyzable group, or a hydrocarbon group; with the proviso that a compound of the formula (I) wherein k=1 and all Y are an alkyl group in all units in parentheses with the subscript β is excepted;

Q represents, each independently at each occurrence, —Z—SiR 1 p R 2 3−p ;

Z represents, each independently at each occurrence, a divalent organic group: with the proviso that Z is not a group which forms a siloxane bond together with a Si atom present in the end of the formula (1),

R 1 represents, each independently at each occurrence, a hydroxyl group or a hydrolyzable group;

R 2 represents, each independently at each occurrence, a C 1-22 alkyl group or Q′;

Q′ has the same definition as that of Q;

p is, each independently in each Q and Q′, an integer of 0-3, and the total sum of p is one or more in the formula (1);

in Q, the number of Si atoms which are straightly linked via the Z group is up to five;

k is, each independently in each unit in parentheses with the subscript β, an integer of 1-3; and

α and β are, each independently, an integer of 1-9, and the sum of α and β is a valence of X.

2. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein k is 2 or more in at least one unit in parentheses with the subscript β in the formula (1).

3. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein k is 3 in at least one unit in parentheses with the subscript β in the formula (1).

4. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein k is 3 in all units in parentheses with the subscript β in the formula (1).

5. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein the number of Si atoms which are straightly linked via the Z group in Q is one or two.

6. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein the number of Si atoms which are straightly linked via the Z group in Q is one.

7. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein Rf is a C 1-16 perfluoroalkyl group in the formula (1).

8. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein PFPE in the formula (1) is a group of the following formula (a) or (b):

—(OC 3 F 6 ) b —  (a)

in the formula (a), b is an integer of from 1 or more and 200 or less; or

—(OC 4 F 8 ) a —(OC 3 F 6 ) b —(OC 2 F 4 ) c —(OCF 2 ) d —  (b)

in the formula (b), a and b are each independently an integer of 0 or more and 30 or less, c and d are each independently an integer of 1 or more and 200 or less, the sum of a, b, c and d is 10 or more and 200 or less, and the occurrence order of the respective repeating units in parentheses with the subscript a, b, c or d is not limited in the formula.

9. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein in PFPE in the formula (1):

—(OC 4 F 8 ) a — is —(OCF 2 CF 2 CF 2 CF 2 ) a —,

—(OC 3 F 6 ) b — is —(OCF 2 CF 2 CF 2 ) b —, and

—(OC 2 F 4 ) c — is —(OCF 2 CF 2 ) c —.

10. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein X in the formula (1) is a 3-5 valent organic group.

11. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein X in the formula (1) is a group selected from the group consisting of:

wherein in each X group, at least one of T is a following group attached to PFPE in the formula (1):

—CH 2 O(CH 2 ) 2 —,

—CH 2 O(CH 2 ) 3 —,

—CF 2 O(CH 2 ) 3 —,

—(CH 2 ) 2 —,

—(CH 2 ) 3 —,

—(CH 2 ) 4 —,

—CONH—(CH 2 ) 3 —,

—CON(CH 3 )—(CH 2 ) 3 —,

—CON(Ph)-(CH 2 ) 3 — wherein Ph represents a phenyl group, and

at least one of the other T is —(CH 2 ) n — (wherein n is an integer of 2-6) attached to the Si atom in the formula (1), and

the others are, each independently, a methyl group or a phenyl group,

R 41 represents a hydrogen atom, a phenyl group or an alkyl group having 1 to 6 carbon atoms, and

R 42 represents a hydrogen atom or a C 1-6 alkyl group.

12. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein Y is, each independently at each occurrence, selected from the group consisting of a hydroxyl group and a hydrolyzable group.

13. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein the hydrolyzable group in Y is, each independently at each occurrence, selected form a group of —OR 7 wherein R 7 is a C 1-12 alkyl group.

14. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein the hydrocarbon group in Y is, each independently at each occurrence, selected from the group consisting of a C 1-12 alkyl group, a C 2-12 alkenyl group, a C 2-12 alkynyl group and a phenyl group.

15. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein in Q in the formula (1), p is 3.

16. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein

Rf is a C 1-16 perfluoroalkyl group,

PFPE is a group of the following formula (a) or (b):

—(OC 3 F 6 ) b —  (a)

wherein b is an integer of 1 or more and 200 or less; or

—(OC 4 F 8 ) a —(OC 3 F 6 ) b —(OC 2 F 4 ) c —(OCF 2 ) d —  (b)

wherein a and b are each independently an integer of 0 or more and 30 or less, c and d are each independently an integer of 1 or more and 200 or less, the sum of a, b, c and d is 10 or more and 200 or less, and the occurrence order of the respective repeating units in parentheses with the subscript a, b, c or d is not limited in the formula,

X is a 4-valent or 5-valent organic group,

k is 3, and

p is 3.

17. The perfluoro(poly)ether group containing silane compound according to claim 1 wherein a number average molecular weight of the PFPE moiety is 500-30,000.

18. The perfluoro(poly)ether group containing silane compound according to claim 1 , having a number average molecular weight of 1,000-40,000.

19. A surface-treating agent comprising at least one perfluoro(poly)ether group containing silane compound of the formula (1) according to claim 1 .

20. The surface-treating agent according to claim 19 , further comprising one or more components selected form a fluorine-containing oil, a silicone oil and a catalyst.

21. The surface-treating agent according to claim 20 wherein the fluorine-containing oil is one or more compounds of the formula (3):

R 21 —(OC 4 F 8 ) a′ —(OC 3 F 6 ) b′ —(OC 2 F 4 ) c′ —(OCF 2 ) d′ —R 22   (3)

wherein:

R21 represents a C 1-16 alkyl group which may be substituted by one or more fluorine atoms;

R 22 represents a C 1-16 alkyl group which may be substituted by one or more fluorine atoms, a hydrogen atom or a fluorine atom; and

a′, b′, c′ and d′ represent the repeating number of each of four repeating units of perfluoro(poly)ether which constitute a main backbone of the polymer, and are each independently an integer of 0 or more and 300 or less, the sum of a′, b′, c′ and d′ is 1 or more, and the occurrence order of the respective repeating units in parentheses with the subscript a′, b′, c′ and d′ is not limited in the formula.

22. The surface-treating agent according to claim 20 wherein the fluorine-containing oil is one or more compounds of the formula (3a) or (3b):

R 21 —(OCF 2 CF 2 CF 2 ) b″ —R 22   (3a)

R 21 —(OCF 2 CF 2 CF 2 CF 2 ) a″ —(OCF 2 CF 2 CF 2 ) b″ —(OCF 2 CF 2 ) c″ —(OCF 2 ) d″ —R 22   (3b)

wherein:

R 21 and R 22 are as defined in any preceding claims;

in the formula (3a), b″ is an integer of 1 or more and 100 or less;

in the formula (3b), a″ and b″ are each independently an integer of 0 or more and 30 or less, and c″ and d″ are each independently an integer of 1 or more and 300 or less; the sum of a″, b″, c″ and d″ is an integer of one or more and 300 or less;

the occurrence order of the respective repeating units in parentheses with the subscript a″, b″, c″ or d″ is not limited in the formula.

23. The surface-treating agent according to claim 22 , at least comprising one or more compounds of the formula (3b).

24. The surface-treating agent according to claim 22 , comprising the compound of the formula (3a) and the compound of the formula (3b) at a mass ratio of 1:1-1:30.

25. The surface-treating agent according to claim 22 , comprising the compound of the formula (3a) and the compound of the formula (3b) at a mass ratio of 1:1-1:10.

26. The surface-treating agent according to claim 22 comprising the compound of the formulae (3b), wherein a mass ratio of the at least one perfluoro(poly)ether group containing silane compound of the formula (1) according to claim 1 and the compound of the formula (3b) is 4:1-1:4.

27. The surface-treating agent according to claim 22 wherein the compound of the formula (3a) has a number average molecular weight of 2,000-8,000.

28. The surface-treating agent according to claim 22 wherein the compound of the formula (3b) has a number average molecular weight of 2,000-30,000.

29. The surface-treating agent according to claim 22 wherein the compound of the formula (3b) has a number average molecular weight of 8,000-30,000.

30. The surface-treating agent according to claim 19 , further comprising a solvent.

31. A method of imparting antifouling property to a base material which comprises applying the surface-treating agent according to claim 19 on a surface of the base material.

32. A method of forming a surface-treating layer on a base material which comprises depositing the surface-treating agent according to claim 19 on a surface of the base material by vacuum deposition.

33. A pellet comprising the surface-treating agent according to claim 19 .

34. An article comprising a base material and a layer which is formed on a surface of the base material from the surface-treating agent according to claim 19 .

35. The article according to claim 34 which is an optical member.

36. The article according to claim 34 which is a display.