Fluorine-containing ether compound, lubricant for magnetic recording medium, and magnetic recording medium

1. A fluorine-containing ether compound represented by the following Formula (1):

R 1 —R 2 —CH 2 —R 3 —CH 2 —OCH 2 CH(OH)CH 2 O—CH 2 —R 3 —CH 2 —R 4 —R 5   (1)

(in Formula (1), R 3 represents a perfluoropolyether chain; R 2 and R 4 represent a divalent linking group having a polar group, and may be the same as or different from each other; R 1 and R 5 represent a terminal group bonded to an oxygen atom of R 2 or R 4 , and may be the same as or different from each other; and at least one of R 1 and R 5 is an organic group having 1 to 8 carbon atoms and at least one of hydrogens included in the organic group is substituted by a cyano group).

2. The fluorine-containing ether compound according to claim 1 ,

wherein the organic group is a phenyl group, or an alkyl group having 1 to 5 carbon atoms.

3. The fluorine-containing ether compound according to claim 1 ,

wherein the polar group is a hydroxyl group.

4. The fluorine-containing ether compound according to claim 3 ,

wherein, in Formula (1), a total number of a hydroxyl group contained in R 2 and a hydroxyl group contained in R 4 is 2 to 5.

5. The fluorine-containing ether compound according to claim 1 ,

wherein, in Formula (1), R 2 and R 4 contain 1 to 3 linking groups represented by the following Formula (2):

—CH 2 CH(OH)CH 2 —  (2)

6. The fluorine-containing ether compound according to claim 5 ,

wherein, in Formula (1), R 2 and R 4 are a linking group represented by the following Formula (2-1):

—O—X—(Y 1 X) a —Y 2 —  (2-1)

(in Formula (2-1), a represents an integer of 0 to 2; X represents Formula (2); Y 1 represents any one selected from the group consisting of —O—, —CH 2 —, —CH 2 O—, and —OCH 2 —; and

Y 2 represents —O— or —CH 2 O—).

7. The fluorine-containing ether compound according to claim 6 , wherein, in Formula (2-1), Y 1 and Y 2 are —O—.

8. The fluorine-containing ether compound according to claim 1 ,

wherein, in Formula (1), R 3 is any one selected from the group consisting of perfluoropolyether chains represented by the following Formulae (3) to (5):

—CF 2 —(OCF 2 CF 2 ) b —(OCF 2 ) c —OCF 2 —  (3)

(in Formula (3), b and c indicate an average degree of polymerization, b represents 1 to 20, and c represents 0 to 20),

—CF 2 —(OCF 2 CF 2 CF 2 ) d —(OCF 2 CF 2 —  (4)

(in Formula (4), d indicates an average degree of polymerization, and represents 1 to 20), and

—CF 2 CF 2 CF 2 —(OCF 2 CF 2 CF 2 CF 2 ) e —OCF 2 CF 2 CF 2 —  (5)

(in Formula (5), e indicates an average degree of polymerization, and represents 1 to 10).

9. The fluorine-containing ether compound according to claim 1 ,

wherein, in Formula (1), R 1 and R 5 are a phenyl group which is substituted with at least one cyano group, or an alkyl group having 1 to 5 carbon atoms which is substituted with at least one cyano group.

10. The fluorine-containing ether compound according to claim 1 ,

wherein, in Formula (1), two perfluoropolyether chains represented by R 3 are the same, R 2 and R 4 are the same, and R 1 and R 5 are the same.

11. The fluorine-containing ether compound according to claim 1 ,

wherein, in Formula (1),

one of R 1 and R 5 is a phenyl group which is substituted with at least one cyano group, or an alkyl group having 1 to 5 carbon atoms which is substituted with at least one cyano group, and

the other of R 1 and R 5 is an organic group which includes at least one selected from the group consisting of an aromatic hydrocarbon-containing group, an aromatic heterocycle-containing group, an alkenyl group, and an alkynyl group.

12. The fluorine-containing ether compound according to claim 1 , which is any of compounds represented by the following Formulae (A) to (P):

(in Formula (A), ma1, ma2, na1, and na2 indicate an average degree of polymerization, ma1 and ma2 represent 1 to 20, and na1 and na2 represent 0 to 20),

(in Formula (B), mb1, mb2, nb1, and nb2 indicate an average degree of polymerization, mb1 and mb2 represent 1 to 20, and nb1 and nb2 represent 0 to 20),

in Formula (C), mc1, mc2, nc1, and nc2 indicate an average degree of polymerization, mcl and mc2 represent 1 to 20, and nc1 and nc2 represent 0 to 20), and

(in Formula (D), md1, md2, nd1, and nd2 indicate an average degree of polymerization, md1 and md2 represent 1 to 20, and nd1 and nd2 represent 0 to 20),

(in Formula (E), me1 me2, ne1, and ne2 indicate an average degree of polymerization, me1 and me2 represent 1 to 20, and ne1 and ne2 represent 0 to 20),

(in Formula (F), mf1, mf2, nf1, and nf2 indicate an average degree of polymerization, mf1 and mf2 represent 1 to 20, and nf1 and nf2 represent 0 to 20),

(in Formula (G), mg1, mg2, ng1, and ng2 indicate an average degree of polymerization, mg1 and mg2 represent 1 to 20, and ng1 and ng2 represent 0 to 20), and

(in Formula (H), mh1, mh2, nh1, and nh2 indicate an average degree of polymerization, mh1 and mh2 represent 1 to 20, and nh1 and nh2 represent 0 to 20),

(in Formula (I), mi1, mi2, ni1, and ni2 indicate an average degree of polymerization, mil and mi2 represent 1 to 20, and ni1 and ni2 represent 0 to 20),

(in Formula (J), mj1, mj2, nj1, and nj2 indicate an average degree of polymerization, mj1 and mj2 represent 1 to 20, and nj1 and nj2 represent 0 to 20),

in Formula (K), mk1, mk2, nk1, and nk2 indicate an average degree of polymerization, mk1 and mk2 represent 1 to 20, and nk1 and nk2 represent 0 to 20), and

(in Formula (L), ml1, ml2, nl1, and nl2 indicate an average degree of polymerization, ml1 and ml2 represent 1 to 20, and nl1 and nl2 represent 0 to 20),

(in Formula (M), mm1, mm2, nm1, and nm2 indicate an average degree of polymerization, mm1 and mm2 represent 1 to 20, and nm1 and nm2 represent 0 to 20),

(in Formula (N), mn1, mn2, nn1, and nn2 indicate an average degree of polymerization, mn1 and mn2 represent 1 to 20, and nn1 and nn2 represent 0 to 20),

(in Formula (O), po1 and po2 indicate an average degree of polymerization, and each represent 1 to 20), and

(in Formula (P), qp1 and qp2 indicate an average degree of polymerization, and each represent 1 to 10).

13. The fluorine-containing ether compound according to claim 1 ,

wherein the number-average molecular weight thereof is in a range of 500 to 10,000.

14. A lubricant for a magnetic recording medium, which contains the fluorine-containing ether compound according to claim 1 .

15. A magnetic recording medium having at least a magnetic layer, a protective layer, and a lubricating layer sequentially provided on a substrate,

wherein the lubricating layer contains the fluorine-containing ether compound according to claim 1 .

16. The magnetic recording medium according to claim 15 , wherein the average film thickness of the lubricating layer is 0.5 nm to 2.0 nm.