Fluoropolyether compound, and lubricant and magnetic disc comprising same

Abstract

A compound of the formula (1), lubricant containing the compound and magnetic disk
R.sup.1C.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2R.sup.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4R.sup.1 (1)
wherein R.sup.1 is alkoxyl having 1 to 4 carbon atoms, amino or amido, R.sup.2 is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2CF.sub.2CF.sub.2, z is a real number of 1 to 15, n is a real number of 0 to 4.

Claims

1. A compound of the formula (1)
R.sup.1C.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2R.sup.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4R.sup.1 (1) wherein R.sup.1 is alkoxyl having 1 to 4 carbon atoms, amino or amido, R.sup.2 is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2CF.sub.2CF.sub.2, z is a real number of 1 to 15, n is a real number of 0 to 4.

2. A compound as defined in claim 1 wherein z is a real number of 1 to 10.

3. A compound as defined in claim 1 wherein R.sup.2 is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2, z is a real number of 1 to 15.

4. A compound as defined in claim 1 wherein R.sup.2 is CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2CF.sub.2CF.sub.2, n is a real number of 0 to 4.

5. A lubricant containing a compound of the formula (1)
R.sup.1C.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2R.sup.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4R.sup.1 (1) wherein R.sup.1 is alkoxyl having 1 to 4 carbon atoms, amino or amido, R.sup.2 is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2CF.sub.2CF.sub.2, z is a real number of 1 to 15, n is a real number of 0 to 4.

6. A lubricant as defined in claim 5 wherein z is a real number of 1 to 10.

7. A magnetic disk comprising at least a recording layer and a protective layer formed over a substrate, and a lubricating layer formed over the resulting surface, the lubricating layer containing a compound of the formula (1)
R.sup.1C.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2R.sup.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4R.sup.1 (1) wherein R.sup.1 is alkoxyl having 1 to 4 carbon atoms, amino or amido, R.sup.2 is CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2 or CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2CF.sub.2CF.sub.2, z is a real number of 1 to 15, n is a real number of 0 to 4.

8. A magnetic disk as defined in claim 7 wherein z is a real number of 1 to 10.

Description

BRIEF DESCRIPTION OF THE DRAWING

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

EXAMPLES

(2) The invention will be described in more detail with reference to the following examples to which, however, the invention is not limited.

Example 1

Preparation of CH3OC6H4OCH2CH(OH)CH2OCH2CF2CF2O(CF2CF2CF2O)zCF2CF2CH2OCH2CH(OH)CH2OC6H4OCH3 (Compound 1)

(3) t-Butanol (45 g), 96 g of a fluoropolyether of the formula HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2CH.sub.2OH which is 1805 in number average molecular weight and 1.27 in molecular weight distribution, potassium t-butoxide (0.5 g) and glycidyl 4-methoxyphenyl ether (15 g) were stirred at 70 C. in an argon atmosphere for 14 hours. The mixture was thereafter washed with water, dewatered and purified by distillation, affording 90 g of Compound 1.

(4) Compound 1 was a colorless transparent liquid and 1.75 g/cm.sup.3 in density at 20 C. Compound 1 was identified by NMR with the result shown.

(5) .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as -129.7 ppm)

(6) =129.7 ppm

(7) [20F, OCF.sub.2CF.sub.2CF.sub.2O]

(8) =83.7

(9) [40F, OCF.sub.2CF.sub.2CF.sub.2O]

(10) =124.2 ppm

(11) [4F, OCF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4CH.sub.3]

(12) =86.5 ppm

(13) [4F, OCF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4OCH.sub.3]

(14) Z=6.3

(15) .sup.1H-NMR (solvent: none, reference material: D.sub.2O)

(16) =3.23.8 ppm

(17) [22H, H.sub.3COC.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4OCH.sub.3]

(18) =6.1 ppm, 6.7 ppm

(19) [8H, OCF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2C.sub.6H.sub.4OCH.sub.3]

Example 2

Preparation of CH3OC6H4OCH2CH(OH)CH2OCH2CF2CF2CF2O(CF2CF2CF2CF2O)nCF2CF2CF2CH2OCH2CH(OH)CH2OC6H4OCH3 (Compound 2)

(20) The reaction was conducted in the same manner as in Example 1 except that a fluoropolyether of the formula HOCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2CF.sub.2CF.sub.2CH.sub.2OH is used in place of the fluoropolyether of the formula HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2CH.sub.2OH used in Example 1, affording 61 g of Compound 2.

(21) Compound 2 was a colorless transparent liquid and 1.70 g/cm.sup.3 in density at 20 C. Compound 2 was identified by NMR with the result shown.

(22) .sup.19F-NMR (solvent: none, reference material: OCF.sub.2CF.sub.2CF.sub.2CF.sub.2O in the obtained product being taken as 125.8 ppm):

(23) =83.7 ppm

(24) [16F, OCF.sub.2CF.sub.2CF.sub.2CF.sub.2O, OCF.sub.2CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4OCH.sub.3],

(25) =123.3 ppm

(26) [4F, OCF.sub.2CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4OCH.sub.3],

(27) =125.8 ppm

(28) [12F, OCF.sub.2CF.sub.2CF.sub.2CF.sub.2O],

(29) =127.6 ppm

(30) [4F, OCF.sub.2CF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2C.sub.6H.sub.4OCH.sub.3]

(31) N=3.0

(32) .sup.1H-NMR (solvent: none, reference material: D.sub.2O)

(33) =3.23.8 ppm

(34) [22H, CH.sub.3OC.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2CF.sub.2CH.sub.2OOCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4OCH.sub.3]

(35) =6.1 ppm, 6.7 ppm

(36) [8H, OCF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2C.sub.6H.sub.4OCH.sub.3]

Example 3

Evaluation of Reat Resistance

(37) A lubricant was checked for heat resistance by measuring a temperature when the lubricant decreased 10 percent in weight by heated in an atmosphere of nitrogen at a rate of 2 C./minute using a thermal analyzer (TG/TDA).

Example 4

Measurement of Bonded Ratio

(38) Lubricant 1 prepared in Example 1 was dissolved in Vertrel-XF, product of DuPont. 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 coated with the lubricant was thereafter held for 10 to 20 seconds in an ultraviolet irradiator equipped with a low-pressure mercury lamp which emits UV light of wavelength of 185 nm and 254 nm. At this irradiation, the air inside of the ultraviolet irradiator was substituted by nitrogen beforehand to prevent the formation of ozone. 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 room 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

Example 5

Measurement of Decomposition Resistance to Aluminum Oxide

(39) A sample was used for evaluation which was prepared from each of Compounds 1 and 2, by adding 20 wt. % of Al.sub.2O.sub.3 to the lubricant, intensely shaking the mixture and thereafter thoroughly agitating the mixture with ultrasonic waves. The sample was checked for decomposition resistance using a thermal analyzer (TG/TDA). The sample was heated at 250 C. for 100 minutes, and the weight reduction (B) of the lubricant was measured. For comparison, 20 mg of each of Compounds 1 and 2 was thermally analyzed in the same manner as above with the exception of adding no Al.sub.2O.sub.3 to obtain the weight reduction (C). Decomposition Resistance was evaluated by (B-C).

(40) Also used for comparison were Lubricant 3 having hydroxyl at opposite terminals, and Lubricant 4 having aromatic group at opposite terminals of a perfluoropolyether and Fomblin structure.
HOCH.sub.2CH(OH)CH.sub.2OCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.x(CF.sub.2O).sub.yCF.sub.2CH.sub.2CH.sub.2CH(OH)CH.sub.2OH(Lubricant 3)
wherein x is 9.8, y is 9.7, and 1.20 in molecular weight distribution.
CH.sub.3OC.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2CF.sub.2O(CF.sub.2CF.sub.2O).sub.v(CF.sub.2O).sub.wCF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OC.sub.6H.sub.4OCH.sub.3(Lubricant 4)
wherein v is 10.1, w is 10.9, and 1.18 in molecular weight distribution.

(41) Table 1 shows the evaluation of bonded ratio, heat resistance and decomposition resistance to aluminum oxide These results indicate that the perfluoropolyether compounds of the invention having aromatic group at opposite terminals have superior effect in bonded ratio, heat resistance and decomposition resistance than that of the perfluoropolyether compound having hydroxyl at opposite terminals, or that of a compound having aromatic group at opposite terminals of a perfluoropolyether and Fomblin structure.

(42) TABLE-US-00001 TABLE 1 Bonded Heat Decomposition ratio resistance Resistance to Specimen (%) ( C.) aluminum oxide (%) Compound 1 88 300 3 Compound 2 85 302 3 Lubricant 3 80 224 31 Lubricant 4 82 252 <15

Example 6

Preparation of Magnetic Disk

(43) Each of Compounds 1 and 2 obtained in examples was dissolved in Vertrel-XF, product of DuPont. The solution was 0.05 wt. % in the concentration of Compounds 1 and 2. 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.

(44) Table 2 shows the results. It was confirmed that the magnetic disk can be obtained which is coated with the present compound, and has higher decomposition resistance and a smaller mono-layer thickness.

(45) TABLE-US-00002 TABLE 2 Film thickness Specimen () Compound 1 11 Compound 2 11

INDUSTRIAL APPLICABILITY

(46) The fluoropolyether compounds of the invention having an aromatic group are highly stable to heat compared with the conventionally used compounds having (CF.sub.2O)n(CF.sub.2CF.sub.2O)m-structure (Fomblin structure). Thus, it is possible to provide a lubricating film which is hardly deteriorated with use under high heat environment for a long period of time.

EXPLANATION OF THE SYMBOL

(47) 1: substrate;

(48) 2: recording layer;

(49) 3: protective layer;

(50) 4: lubricant layer