Fluoropolyether compound, and lubricant and magnetic disc using same

Abstract

A compound of the formula (1), and lubricant, and magnetic disk each using the same
A-OCH.sub.2RfCH.sub.2B(1)
wherein A is a group of the formula (a) below, B is a group of the formula (b) or (c) or (d) below, p is 0, 1 or 2, q is a real number of 2 to 10, R is C.sub.1-4 fluoroalkyl, Ar is unsubstituted or substituted aromatic group with C.sub.1-30 alkyl or C.sub.1-30 alkoxyl, Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2, x and y are each a real number of 0 to 50. ##STR00001##

Claims

1. A compound of the formula (1)
A-OCH.sub.2RfCH.sub.2B(1) wherein A is a group of the formula (a) below, B is a group of the formula (b) or (c) or (d) below, p is 0, 1 or 2, q is a real number of 2 to 10, R is C.sub.1-4 fluoroalkyl, Ar is unsubstituted or substituted aromatic group with C.sub.1-30 alkyl or C.sub.1-30 alkoxyl, Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2, x and y are each a real number of 0 to 50 ##STR00005##

2. A compound as defined in claim 1 wherein B is a group of the formula (b), and p is 1 or 2.

3. A compound as defined in claim 1 wherein Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2, x is a real number of 0 to 50.

4. A compound as defined in claim 1 wherein Rf is CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2, y is a real number of 0 to 50.

5. A lubricant containing a compound of the formula (1)
A-OCH.sub.2RfCH.sub.2B(1) wherein A is a group of the formula (a) below, B is a group of the formula (b) or (c) or (d) below, p is 0, 1 or 2, q is a real number of 2 to 10, R is C.sub.1-4 fluoroalkyl, Ar is unsubstituted or substituted aromatic group with C.sub.1-30 alkyl or C.sub.1-30 alkoxyl, Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2, x and y are each a real number of 0 to 50 ##STR00006##

6. A lubricant as defined in claim 5 wherein B is a group of the formula (b), and p is 1 or 2.

7. A magnetic disk having at least a recording layer and a protective layer formed over a substrate, and a lubricant layer provided over a surface of the resulting assembly and comprising a compound containing a perfluoropolyether structure, the disk having a compound of the formula (1) as the lubricant layer
A-OCH.sub.2RfCH.sub.2B(1) wherein A is a group of the formula (a) below, B is a group of the formula (b) or (c) or (d) below, p is 0, 1 or 2, q is a real number of 2 to 10, R is C.sub.1-4 fluoroalkyl, Ar is unsubstituted or substituted aromatic group with C.sub.1-30 alkyl or C.sub.1-30 alkoxyl, Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2, x and y are each a real number of 0 to 50 ##STR00007##

8. A magnetic disk as defined in claim 7 wherein B is a group of the formula (b), and p is 1 or 2.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a section view showing the structure of the magnetic disk of the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

(2) The invention will be described in more detail with reference to the following examples and test examples to which, however, the invention is not limited. .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as 129.7 ppm): .sup.1H-NMR (solvent: perfluorobenzene, reference material: D.sub.2O)

Example 1

Preparation of A-OCH2RfCH2B (Compound I)

(3) A is a group of the formula (a) below, B is a group of the formula (b) below, p is 1, R is m-CF.sub.3, and Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2.

(4) ##STR00003##

(5) In an argon atmosphere, ditrifluoromethylbenzene (114 g), penta-(trifluoromethylphenoxy)-cyclotriphosphonitrile chloride (114 g), HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2CF.sub.2OCH.sub.2CH.sub.2(OH)CH.sub.2OH (2000 in average molecular weight) which corresponds to the formula of HOCH.sub.2RfCH.sub.2-(b) and metallic sodium (0.9 g) were mixed and stirred at 70 C. for 19 hours. The resulting mixture was washed with water and subsequently purified by column chromatography, affording 46 g of the desired Compound I.

(6) Compound I was a colorless transparent liquid and had a density of 1.75 g/cm.sup.3 at 20 C. Compound I was identified by NMR with the result shown. Compound I as obtained was used for .sup.19F-NMR. .sup.1H-NMR analysis was conducted by a sample obtained by adding trifluoroacetic anhydride to Compound I to modify the hydroxyl to an ester.

(7) .sup.19F-NMR (solvent: none):

(8) =64.6 ppm

(9) [15F, [P.sub.3N.sub.3 (OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2]

(10) =86.5 ppm, 124.2 ppm

(11) [4F, CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH]

(12) =86.1 ppm, 124.5 ppm

(13) [4F, [P.sub.3N.sub.3(OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2CF.sub.2]

(14) x=12.6

(15) .sup.1H-NMR (solvent: perfluorohexane, reference material: D.sub.2O):

(16) =3.924.01 ppm

(17) [4H, CF.sub.2CH.sub.2OCH.sub.2CH(OCOCF.sub.3)CH.sub.2OCOCF.sub.3],

(18) =3.953.91 ppm

(19) [2H, [P.sub.3N.sub.3 (OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2],

(20) =4.474.53 ppm

(21) [2H, CF.sub.2CH.sub.2OCH.sub.2CH(OCOCF.sub.3)CH.sub.2OCOCF.sub.3],

(22) =5.315.36 ppm

(23) [1H, CF.sub.2CH.sub.2OCH.sub.2CH(OCOCF.sub.3)CH.sub.2OCOCF.sub.3]

Example 2

Preparation of A-OCH2RfCH2B (Compound II)

(24) Compound II was prepared in the same manner as in Example 1 except that HOCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.yCF.sub.2CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH (40 g, 2000 in average molecular weight) was used as the fluoropolyether of the formula HOCH.sub.2RfCH.sub.2 (b).

(25) Compound II was a colorless transparent liquid and had a density of 1.75 g/cm.sup.3 at 20 C. Compound II was identified by NMR with the result shown. Compound II as obtained was used for .sup.19F-NMR.

(26) .sup.19F-NMR (solvent: none):

(27) =64.6 ppm

(28) [15F, [P.sub.3N.sub.3(OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2]

(29) =120.3 ppm

(30) [4F, CF.sub.2CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH, [P.sub.3N.sub.3 (OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2CF.sub.2CF.sub.2]

(31) =127.6 ppm

(32) [4F, CF.sub.2CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH, [P.sub.3N.sub.3(OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2CF.sub.2CF.sub.2]

(33) y=7.0

Example 3

Preparation of A-OCH2RfCH2B (Compound III)

(34) Compound III was prepared in the same manner as in Example 1 except that HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2CH.sub.2O(CH.sub.2).sub.2OH (47 g, 2000 in average molecular weight) was used as the fluoropolyether of the formula HOCH.sub.2RfCH.sub.2 (c).

(35) Compound III was a colorless transparent liquid and had a density of 1.74 g/cm.sup.3 at 20 C. Compound III was identified by NMR with the result shown. Compound III as obtained was used for .sup.19F-NMR.

(36) .sup.19F-NMR (solvent: none):

(37) =64.1 ppm

(38) [15F, [P.sub.3N.sub.3(OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2]

(39) =86.7 ppm

(40) [2F, CF.sub.2CF.sub.2CH.sub.2O(CH.sub.2).sub.2OH]

(41) =124.4 ppm

(42) [2F, CF.sub.2CF.sub.2CH.sub.2O(CH.sub.2).sub.2OH]

(43) =86.3 ppm

(44) [2F, [P.sub.3N.sub.3 (OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2CF.sub.2]

(45) =124.8 ppm

(46) [2F, [P.sub.3N.sub.3 (OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2CF.sub.2]

(47) x=9.8

Example 4

Preparation of A-OCH2RfCH2B (Compound IV)

(48) Compound IV was prepared in the same manner as in Example 1 except that HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.xCF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2O methoxyphenyl-p (40 g, 2000 in average molecular weight) was used as the fluoropolyether of the formula HOCH.sub.2RfCH.sub.2 (d).

(49) Compound IV was a colorless transparent liquid and had a density of 1.75 g/cm.sup.3 at 20 C. Compound IV was identified by NMR with the result shown. Compound IV as obtained was used for .sup.19F-NMR.

(50) .sup.19F-NMR (solvent: none):

(51) =63.8 ppm

(52) (15F, [P.sub.3N.sub.3(OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2)

(53) =86.2 ppm, 123.9 ppm

(54) (4F, CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OAr)

(55) =86.1 ppm, 124.5 ppm

(56) (4F, [P.sub.3N.sub.3(OC.sub.6H.sub.4CF.sub.3).sub.5]OCH.sub.2CF.sub.2CF.sub.2)

(57) x=9.4

Test Example 1

Measurement of Decomposition Resistance to Aluminum Oxide

(58) A sample was used which was prepared from Compound I prepared in Example 1, by adding 20 wt. % of Al.sub.2O.sub.3 (ICN Alumina B, Akt. I, product of MP Biomedicals, 100 m in mean particle size) to the compound, intensely shaking the mixture and thereafter thoroughly agitating the mixture with ultrasonic waves. The sample was checked for thermal behavior in the presence of Al.sub.2O.sub.3 using a thermal analyzer (TG/TDA). The sample (20 mg) was placed into an aluminum container and heated in a nitrogen atmosphere at a constant temperature of 250 C., and the weight reduction of the compound was measured after the lapse of 100 minutes and 200 minutes. For comparison, 20 mg of Compound I was thermally analyzed in the same manner as above with the exception of adding no Al.sub.2O.sub.3. For further comparison, Compounds V to XIII were also used.

(59) Compound V: PHOSFAROL ADOH, product of MORESCO Corporation

(60) Compound VI: PHOSFAROL A20H-2000, product of MORESCO Corporation

(61) Compound VII: PHOSFAROL A20H-DD

(62) Compound XIII: Fomblin Ztetraol-2000S, product of Solvay Solexis Inc.
A-OCH.sub.2RfCH.sub.2B(Compound V)
A is a group of the formula (a) below, B is a group of the formula (b) below, p is 1, R is m-CF.sub.3, and Rf is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.a(CF.sub.2O).sub.bCF.sub.2, a is 10.5, b is 10.1.

(63) ##STR00004##

(64) Table 1 shows the evaluation results. Table 1 reveals that the fluoropolyether compounds of the present invention are found to have high decomposition resistance compared with Compounds V to XIII.

(65) TABLE-US-00001 TABLE 1 Ratio of decrease in weight (%) Absence of Al.sub.2O.sub.3 Presence of Al.sub.2O.sub.3 After After After After Specimen 100 min 200 min 100 min 200 min Compound I 1 1 3 3 Compound V (ADOH) 2 3 5 9 Compound VI (A20H-2000) 5 9 6 8 Compound VII (A20H-DD) 3 4 4 5 Compound VIII 26 37 39 97 (Ztetraol-2000S)

Test Example 2

Measurement of Bonded Ratio

(66) Compound I prepared in Example 1 was dissolved in Vertrel-XF, product of DuPont. The solution was 0.1 wt. % in the concentration of the compound. A magnetic disk, 2.5 inches in diameter, was immersed in the solution for 1 minute and then withdrawn at a rate of 2 mm/s. The disk was thereafter held in a constant-temperature chamber at 150 C. for 10 minutes to promote the adhesion of the lubricant to the disk surface. The average film thickness of the compound on the disk was subsequently measured by a Fourier Transform Infrared Spectrometer (FT-IR). This film thickness was taken as f . Next, the disk was immersed in Vertrel-XF for 10 minutes, withdrawn at a rate of 10 mm/s and thereafter allowed to stand at roam temperature for the evaporation of the solvent. The compound remaining on the disk was thereafter checked by FT-IR for average film thickness. This film thickness was taken as b . The bonded ratio generally in use was used as an indicator for showing the strength of adhesion of the film to the disk. The bonded ratio was expressed by the equation given below.
Bonded ratio(%)=100b/f

(67) Used for comparison were Compound V [PHOSFAROL ADOH] and a perfluoropolyether having two hydroxyl groups at each of opposite terminals (Fomblin Ztetraol-2000S, product of Solvay Solexis, Compound XIII).

(68) HOCH.sub.2CH(OH)CH.sub.2OCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.c(CF.sub.2O).sub.dCF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH (Compound XIII) wherein c is 10.1, d is 10.9.

(69) These compounds were checked for bonded ratio. Table 2 shows the results. It was confirmed that the present fluoropolyether compound I has effects of forming a lubricant layer which firmly adheres to the magnetic disk.

(70) TABLE-US-00002 TABLE 2 Specimen Bonded ratio (%) Compound I 56 Compound V (ADOH) 56 Compound XIII (Ztetraol-2000S) 40

Example 5

Preparation of Magnetic Disk

(71) Compounds I prepared in Example 1 was dissolved in Vertrel-XF, product of DuPont. The solution was 0.05 wt. % in the concentration of the compound. A magnetic disk, 2.5 inches in diameter, was immersed in the solution for 1 minute and then withdrawn at a rate of 2 mm/s. The disk was thereafter dried at 150 C. for 10 minutes. The coated compound was thereafter checked by FT-IR for film thickness.

(72) Table 3 shows the results. It was confirmed that the magnetic disk can be obtained which is coated with the present compound having decomposition suppressing effects. Also a magnetic disk was prepared in the same manner by using Compound VII (A20H-DD).

(73) TABLE-US-00003 TABLE 3 Specimen Film thickness () Compound I 18 Compound VII (A20H-DD) 20

(74) From the above, the perfluoropolyether compound of the present invention having a cyclophosphazene group and hydroxyl is satisfactory in both adhering properties and decomposition suppressing effects against Al.sub.2O.sub.3 in the component of the head, and it is confirmed that the magnetic disk can be obtained which is coated with the compound.

INDUSTRIAL APPLICABILITY

(75) The present fluoropolyether compound having a cyclophosphazene group and hydroxyl is a lubricant which is excellent in decomposition resistance. Further, the magnetic disk using the present compound as a lubricant exhibits high durability to contact or sliding movement between the head and disk.

EXPLANATION OF THE SYMBOL

(76) Indicated at 1 is a substrate; at 2, a recording layer; at 3, a protective layer; and at 4, a lubricant layer.