WO2007043450A1

WO2007043450A1 - Perfluoropolyether compound and lubricant and magnetic disk each containing or employing the same

Info

Publication number: WO2007043450A1
Application number: PCT/JP2006/320023
Authority: WO
Inventors: Nagayoshi Kobayashi; Kazunori Shirai
Original assignee: Matsumura Oil Research Corp.
Priority date: 2005-10-03
Filing date: 2006-09-29
Publication date: 2007-04-19
Also published as: JPWO2007043450A1; JP5034027B2

Abstract

A compound represented by the formula (I): A-CH2CF2O(CF2CF2O)m-(CF2O)n-CF2CH2-B (I) (wherein A is a group represented by the following formula (a); B is a group represented by the following formula (b); R is C2-5 fluoroalkyl; m is 0 or a real number of 1-40; n is 0 or a real number of 1-40; and p is a real number of 1-3).

Description

Description Perfluoropolyether compound, lubricant using the same, and magnetic disk technical field,

The present invention relates to a perfluoropolyether derivative, a lubricant containing the same, and a magnetic disk using the same. More specifically, the present invention relates to a compound used as a lubricant for a recording medium such as a magnetic disk which is a large capacity recording medium, and a lubricant containing the compound. Background art

As the recording density of magnetic disks increases, the distance between the magnetic disk, which is the recording medium, and the head for recording / reproducing information has become narrow until almost in contact. Lubricating layer is provided a wear upon contact sliding between the head at the depression ¹ obtaining object to the magnetic disk surface. This lubricating layer is usually formed by applying a lubricant to the surface of the magnetic disk. As the lubricant, perfluoropolyether is generally used, and among them, Fo 1 mb 1 in-based compounds made by So 1 Vay Solexis, which have low adhesion to the head and low friction, are the mainstream. It is. The basic skeleton of the Fomb 1 in compound is a perfluoropolyether having a repeating unit of (CF ₂ CF ₂ 0) m— (CF ₂ 0) n—. However, oxygen atoms in Fomblin's perfluoropolyether chain react with A 1 ₂ 0 _{3 in} the head member that acts as a Lewis acid, and the chain is cleaved (for example, non- (See Patent Document 1). As this cutting progresses, Fomb 1 in perfluoropolyether becomes low molecular weight and eventually volatilizes from the magnetic disk. On the other hand, a compound in which at least one end of a perfluoropolyether having hydroxyl groups at both ends is a cyclophosphazene group substituted with an aryloxy group is disclosed, and a lubricant containing this compound as a component is good Contact · start · strike (CSS) durability is disclosed (for example, refer to Patent Document 1). Although this compound has a perfluoropolyether chain in the molecule, it has high chemical stability against Lewis acid (for example, see Non-Patent Document 2). It is considered that it is stable on the surface of the magnetic disk without being decomposed by contact between the head composed of 1 ₂ 0 ₃ and the magnetic disk. Also, the disk rotation speed is likely to exceed 15,000 rpm in the future. The lubricant must stay on the surface of the magnetic disk without scattering even during high-speed rotation. In other words, in order to ensure the reliability of the magnetic disk, both the chemical stability of the lubricant and the adsorptivity are required.

[Non-Patent Document 1] Macromolecles, 1992, 25 卷, p. 6 791 -6799

[Non-patent Document 2] Digest st 'sof Thematic Recoding Conference, Collado ado, August 2004 p. D6 [Patent Document 1] International Application Publication WOO 1Z21630 Al Brochure Information Record In order to increase the capacity and to speed up recording and playback, the distance between the head and the disk (flying height) will be lowered to the area where it is almost in contact, and the rotation speed of the disk will be more than 15,000 rpm in the near future. Probability is high.

The lubricant located on the disk surface must remain stable for a long time. However, if the flying height is small and the magnetic disk is rotated at high speed, the lubricant is likely to move toward the outer circumference of the disk, and it may be considered that the entire surface of the disk does not exhibit sufficient lubrication. In this case, the head may be destroyed due to poor lubrication, resulting in damage to the disk, and eventually the recording layer of the disk may be destroyed. When the lubricant is decomposed by contact with the head, the recording layer may be similarly destroyed. In order to ensure the reliability of the recording device, a lubricant that exhibits sufficient adsorptivity to the disk surface and is difficult to decompose is necessary. An object of the present invention is to provide a compound that exhibits sufficient adsorptivity on the disk surface and is difficult to decompose, and a lubricant and magnetic disk that simultaneously achieves the two problems of adsorption and lubricant decomposition suppression using the compound. There is to do.

Disclosure of the invention

The present invention relates to the following inventions.

(1) A compound represented by formula (I).

A-CH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m- (CF ₂ 0) n-CF ₂ CH ₂ -B (I)

(Wherein A is the formula, a group represented by the following formula (a) in. Formula B is a group represented by the following formula (b). Here, R represents Furuoroarukiru group of C ₂ ~ ₅ M is 0 or a real number from 1 to 40, n is a real number from 0 or 1 to 40. p is a real number from 1 to 3.)

(2) The compound according to (1) above, wherein m and n are real numbers of 4 to 21, and p is 1 or 2.

(3) A lubricant containing a compound of formula (I).

(4) The lubricant as described above, wherein m and n are real numbers of 4 to 21, and p is 1 or 2. (5) In a magnetic disk having at least a recording layer and a protective layer formed on a support and having a lubricating layer made of a compound having a perfluoropolyether structure on the surface, the lubricating layer is a compound represented by the formula (I) A magnetic disk comprising:

(6) The magnetic disk as described above, wherein m and n are real numbers of 4 to 21, and p is 1 or 2.

In the present invention, perfluoropolyether has a cyclophosphazene group substituted with a fluoroalkoxy group at one end and an oxyalkylene group containing two or more hydroxyl groups at the other end. It has been found that olopolyether compounds can overcome the above problems.

The decomposition of the compound of the present invention is suppressed because the phosphazene ring existing in the molecule acts as a Lewis base and interacts with A 1 ₂ 0 ₃ prior to perfluoropolyether. It is thought to suppress the degradation of olopolyether. Further, the reason why the compound of the present invention exhibits excellent adsorptivity is considered to be that two or more hydroxyl groups of the lubricant form hydrogen bonds with the magnetic disk surface.

[1] The perfluoropolyether represented by the formula (I) of the present invention has a cyclophosphazene group substituted with a fluoroalkoxy (RO) group at one end and two at the other end. A perfluoropolyether compound having an oxyalkylene group containing the above hydroxyl group.

Here, R is a Furuoroarukiru group C ₂ ~ _5, for example, 2; 2, 2-tri Furuoroechiru group, 2, 2, 3, 3-tetrafluoropropoxy O b propyl, 2, 2, 3, 3 , 3- Penyu Fluoropropyl group, 1, 1, 1, 3, 3, 3-Hexafluoro-2-propyl group, 2, 2, 3, 4, 4, 4 _Hexaf J Leolobutyle group, 2, 2, 3 , 3, 4, 4, 4-Heptanefluorobutyl group, 2, 2, 3, 3, 4, 4, 5, 5-octafluoropentyl group, and the like.

[1-1] Synthesis method

The compound (I) of the present invention is produced, for example, by the two-step synthesis method as described below. The first step is perfluoropolyether with fluororesin at one end. This is a synthesis of a perfluoropolyether compound having a cyclophosphazene group substituted with a alkoxy group and one hydroxyl group at the other end. For example, a fluoroalcohol represented by R—OH is previously reacted with an alkali metal or the like to form a fluoroalcohol, then reacted with cyclotriphosphonitrile halide, and further, both ends are hydroxylated with perfluoropolyether and alcohol. Power metal is added to synthesize. More specifically, fluoroalcohol is dissolved in hydrocarbon ether, and metal sodium is added to it. The amount of metal sodium added is 50 to 100% equivalent, preferably 80 to 90% equivalent to the fluoroalcohol. The mixture is then stirred at 20 to 0, preferably -5 to 5 t for 5 to 50 hours, preferably 20 to 30 hours, after which cyclotriphosphonitrile halide is added and further at room temperature 0.5 to 5 Stir for hours, preferably 1-3 hours. After washing with water and distilling, add perfluoropolyether and sodium metal and stir at 90-100 for 20-60 hours, preferably 40-50 hours. The perfluoropolyether and metallic sodium used here are preferably 2 to 3% equivalent and 3 to 4% equivalent respectively to the fluoroalcohol used first. Thereafter, washing with water and purification by column chromatography are performed. At both ends of the perfluoropolyether, which is the target compound in the first step, a cyclophosphazene group substituted at one end with a fluoroalkoxy group, A perfluoropolyether compound having one hydroxyl group at the other end is obtained.

The compound (I) of the present invention is obtained by the second-stage synthesis. For example, the compound (I) of the present invention is produced by reacting the compound obtained in the first step with glycidol. More specifically, the compound obtained in the first step and glycidol are reacted at 60-80 for about 05-5 hours, preferably 1-3 hours. The added amount of dalicidol is preferably 1 to 2 times equivalent to the hydroxyl group of the compound obtained in the first stage. Next, washing with water and molecular distillation are performed to obtain the desired product.

Perfluoropolyethers with hydroxyl groups at both ends include Fomb lin Zd ol, Zdo l—TX, Z tetrao 1 from S ο 1 Vay Solexis and so on. For example, the chemical structure of Fomb lin Z do 1 is HO—CH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m— (CF ₂ 0) n—CF ₂ CH ₂ 0 H, where m = 0 to 40, n = 0 to 40, there is a molecular weight distribution, the average molecular weight is about 1000 to 7 000.

[1 -2] Application

The compound of the present invention can be used as a lubricant for improving the dynamic characteristics of the magnetic disk in the magnetic disk apparatus. In this case, in addition to using the compound of the present invention alone, for example, Fomb 1 in Zdo l, Z tetr ao l, Z do 1 TX, AM, manufactured by Daikin Industries, manufactured by So 1 Vay So 1 exis It can also be used by mixing in any ratio with demnum, Durynt Krytox, etc. In addition to magnetic disks, there are also magnetic heads in magnetic disk devices, recording devices such as magneto-optical recording devices, optical recording devices, magnetic tapes, etc. It can also be used as a lubricant for equipment and as a coating agent for surfaces that require water and oil repellency. In these applications, in addition to using the compound of the present invention alone, it can be used in a mixture with a hydrocarbon-based, fluorine-based, or silicon-based lubricant.

[1-3] How to use

In order to form a lubricating layer using the compound of the present invention, there is a method in which it is applied to the surface in a bulk state, but it sometimes adheres thicker than necessary. In this case, dilute with solvent and apply. Solvents containing fluorine have good compatibility with the compound of the present invention. Examples thereof include 3M PF-5060, PF-5080, HFE-7100, HFE-7200, DuPont Vertrel-XF, and the like. The concentration of the compound of the present invention after dilution is 1% or less, preferably 0.001 to 01%. When used as a lubricant for magnetic disks, the coating method is generally used.

[2] About magnetic disks

[2-1] Configuration of magnetic disk

FIG. 1 is a schematic cross-sectional view of the magnetic disk of the present invention. The magnetic disk of the present invention has at least one recording layer 2 on a support 1, a protective layer 3 thereon, and a lubricating layer 4 containing the compound of the present invention as an outermost layer. This is the configuration. , Examples of the support include aluminum alloys, ceramics such as glass, and polycarbonate.

The magnetic layer, which is the recording layer of the magnetic disk, is composed of an element that can form a ferromagnetic material, such as iron, colt, and nickel, and an alloy obtained by adding chromium, platinum, tantalum, etc. Or those oxides are mentioned. These are formed by a plating method or a sputtering method.

, The protective layer is carbon, S i C, include a material such as S i 0 _2. These are formed by sputtering or CVD.

[2-2] Formation method of lubrication layer

Since the thickness of the lubricant layer is currently 3 nm or less, if the lubricant with a viscosity of 20 and about 10 OmPa * s or more is applied as it is, the film thickness may become too large. Therefore, a solution dissolved in a solvent is used for coating. Even when the compound of the present invention is used alone as a lubricant, for example, Fomb 1 in Zdo l, Z tetr ao l, Zdo l TX, AM, manufactured by S o 1 V ay Solexis, Demnum manufactured by Daikin Industries, Ltd., Even when mixed with D upont's Krytox, etc., it is easier to control the required film thickness by dissolving it in a solvent. However, the concentration varies depending on the application method, conditions, and mixing ratio.

Examples of the coating method include a dipping method and a spin coating method.

The solvent to be used is selected to dissolve the compound of the present invention. Specific examples include fluorine-containing solvents such as 3M-made PF-5060, PF-5080, HFE-7100, HFE-7200, and Durtone 1-XF. The concentration of the compound of the present invention after dilution is 1% or less, preferably 0.001 to 0 1%.

[2-3] Application

The magnetic disk of the present invention stores a disk and records, reproduces, and erases information. It can be applied to a magnetic disk drive comprising a magnetic disk drive equipped with a motor for rotating a disk for the purpose and a control system for controlling the drive. In addition to computers, the magnetic disk of the present invention and the magnetic disk device to which it is applied are used in digital home appliances such as digital video recorders, digital video cameras, digital cameras, and televisions, and also in car navigation systems. It can be applied to electronic devices that record and play back digital information such as Yon systems, game consoles, mobile phones, PHS, and word processors. Brief Description of Drawings

FIG. 1 is a schematic sectional view showing the structure of a magnetic disk of the present invention. 1 is a support, 2 is a recording layer, 3 is a protective layer, and 4 is a lubricating layer. BEST MODE FOR CARRYING OUT THE INVENTION

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and test examples, but the scope of the present invention is not limited to these examples.

Example 1

(CF ₃ CH ₂ 0) ₅ _P ₃ N “OCH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m— (CF ₂ 0) n -CF ₂ CH ₂ 0-CH ₂ CH (OH) CH ₂ OH (however , — P ₃ N ₃ — is cyclic) (Compound 1) synthesis

In an argon atmosphere, tetrahydrofuran (2500 g), trifluoroethanol (870 g) and metallic sodium (180 g) were stirred at 0 for 24 hours, and at 0, cyclotriphosphonitrile chloride (420 g) was added. Slowly added. The reaction mixture was stirred at room temperature for 2 hours, then washed with water and distilled to obtain 830 g of cyclotriphosphonitrile substituted with a trifluoroethoxy group. In addition to this, as perfluoropolyether, both ends of the hydroxyl group are S o 1 V ay Solexis Fomb 1 in Zdo l -2000 (average molecular weight 2000) 520 g and metallic sodium (7 g) was added and stirred at 90 ° C. for 48 hours. This was washed with methanol and purified by column chromatography to obtain 120 g of a compound having one end of the perfluoropolyether of formula (a) and the other end having one hydroxyl group. Under argon atmosphere, 35 g of glycidol in tert-butanol was gradually added dropwise to this compound over 2 hours in 701 using potassium t-butoxide as a catalyst, and the mixture was further stirred for 2 hours after the addition. After the reaction, the solution was washed with water and purified by molecular distillation to obtain 70 g of the intended compound (I).

Compound 1 was a colorless and transparent liquid, and the density at 20 was l. YO gZcm ³ . The identification result of the compound 1 performed using NMR is shown. ^{For 19} F-NMR, Compound 1 was used as is for analysis. — In NMR, a sample in which trifluoroacetic anhydride was added to Compound 1 and the hydroxyl group was converted to an ester was analyzed. ¹⁹ F-NMR (Solvent; none, reference material: OCF ₂ CF ₂ CF ₂ CF ₂ 0 contained in a trace amount in the product is set to 1 125 8 ppm)

(5 = — 76. 1 p pm

[15 F, R f — CF ₂ CH ₂ — O— P ₃ N ₃ _ (OCH ₂ C s) ₅ ]

δ =-77.9 ppm,-79.9 ppm

[2 F, R f —Ci ₂ CH ₂ — O— CH ₂ CH (OH) CH ₂ OH]

δ =-78. 8 p pm,-80 8 p pm

[2 F, R f — CJ1 ₂ CH ₂ — O— P ₃ N ₃ — (OCH ₂ CF ₃ ) ₅ ]

δ = — 80.6 ppm, -82. 6 p pm

(OF, R f -CF ₂ CH ₂ -OH)

m = 10. 6, n = 10 1

^J H-NMR (solvent: perfluorinated hexane, reference material: heavy water):

6 = 5. 26 p pm

[LH, R f — CF ₂ CH ₂ — O— CH ₂ CH (〇COCF ₃ ) CH ₂ ○ C〇CF ₃ ], δ = 5 12 ppm [0H, R f -CF ₉ CH ₉ -Q-CH ₉ CH (0C0CF _¾ ) CH ₂ ○ CH ₂ CH (0 COCF3) CH ₂ OCOCF ₃ ]

Example 2, (CF ₃ CH ₂ 0) P ₃ N ₃ — OCH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m- (CF ₂ 0) n -CF ₂ CH ₂ 0-CH ₂ CH (OH) Synthesis of CH ₂ OH (where 1 P ₃ N ₃ — is cyclic) (compound 2)

The perfluoropolyether described in Example 1 was synthesized according to the method described in Example 1, except that Fomb lin Zdo l -4000 (average molecular weight 4,000) manufactured by Solvay Solexis was used. 30 g of the target (Compound 2) was obtained. Compound 2 was a colorless transparent liquid, and the density at 2 Ot: was 1.75 gZcm ³ . The identification result of the compound 2 performed using NMR is shown. ^{For 19} F-NMR, compound 2 was used as is for analysis. ,

— In NMR, the ester modification prepared according to the method described in Example 1 was analyzed.

1 ⁹ F-NMR (Solvent; none, reference material: OCF ₂ CF ₂ CF ₂ CF ₂ 0 contained in a trace amount in the product is set to 1 125 8 ppm)

(5 =-76.3 p pm

[15 F, R f — CF ₂ CH ₂ — O— P ₃ N ₃ — (OCH ₂ Cj ₃ ) ₅ ]

δ =-77 8 ppm,-79.8 p pm

[2 F, R f _C ₂ CH ₂ — O— CH ₂ CH (OH) CH ₂ OH]

δ =-78.8 p pm,-80.8 p pm

(2 F, R f -CH ₂ CH ₂ -0-P ₃ N _3- (OCH ₂ CF ₃ ) ₅ )

δ = — 80.6 ppm, — 82 6 p pm

CO F, R f -CFl ₂ CH ₂ -OH]

m = 23. 5, n = 23 3

^X H-NMR (solvent: perfluorinated hexane, reference material: heavy water):

δ = 5. 26 ρρπι [LH, R f —CF ₂ CH ₂ — 0— CH ₂ CH (OC ○ CF ₃ ) CH ₂ ○ COCF ₃ ], (5 = 5.1 2 p pm

[0H, R f -CF, CH ₉ -0-CH ₉ CH (0C0CFJ CH ₂ OCH ₂ CH, (○ COCF ₃ ) CH ₂ OC ○ CF ₃ ]

Example 3

(CF ₃ CH ₂ 0) ₅ — P ₃ N ₃ — OCH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m—, (CF ₂ 0) n -CF ₂ CH ₂ 0-CH ₂ CH (OH) CH ₂ OCH ₂ CH (OH) CH ₂ 0H (however, P ₃ N ₃ — is cyclic) (Compound 3) Synthesis

The compound was synthesized according to the method described in Example 1 except that 7.0 g of dalicidol was described in Example 1, and 45 g of the target compound (Compound 3) was obtained. Compound 3 was a colorless transparent liquid, and the density at 20 was 1.61 gZcm ³ . The identification result of the compound 3 performed using NMR is shown. ^{For 19} F-NMR, compound 3 was used as is for analysis. In NMR, the ester modification prepared according to the method described in Example 1 was analyzed.

1 ⁹ F-NMR (solvent; none, reference material: OCF ₂ CF ₂ CF ₂ CF ₂ 0 contained in the product in a trace amount is set to 1 25,8 p pm)

δ = — 76.1 ρ ρ m

[1 5 F, R f -CF ₂ CH ₂ -0-P ₃ N _3- (〇CH ₂ CJ1 ₃ ) ₅ ]

(5 =-77 9 ppm, — 79 9 ρ pm

[2 F, R f -CJF ₂ CH ₂ -0-CH ₂ CH (OH) CH ₂ 0— CH ₂ CH (OH) CH ₂ — OH]

δ =-78. 8 p pm,-80 8 p pm

[2 F, R f -CF. ₂ CH ₂ -0-P ₃ N _3- (OCH ₂ CF ₃ ) ₅ ]

[0 F, R f — C_ £ ₂ CH ₂ —〇H]

m = 10 6, n = 10. 1

^ -NMR (solvent: perfluorinated hexane, reference material: heavy water): δ— 5 26 p pm

[1H, R f -CF ₂ CH ₂ -0-CH ₂ CH (OCOCF ₃ ) CH ₂ OCH ₂ CH. (0 COCF ₃ ) CH ₂ OCOCF ₃ ],, 6 = 5. 12 p pm

(1H, R f-CF ₂ CH ₂ -0-CH ₂ CH. (OCOCF ₃ ) CH ₂ OCH ₂ CH (0 COCF3) CH ₂ OCOCF ₃ )

Example 4

(HCF ₂ CF ₂ CF ₂ CF ₂ CH ₂ 0) ₅ — P ₃ N ₃ _ OCH ₂ CF ₂ 〇 (CF ₂ CF ₂ 0) m- (CF ₂ 0) n-CF ₂ CH ₂ 0-CH ₂ CH (OH) CH ₂ OH (where — P ₃ N ₃ — is cyclic) (Compound 4)

The method described in Example 1 except that 2, 2, 3, 3, 4, 4, 5, 5-octafluoropentanol is used in place of trifluoroethanol described in Example 1. To obtain 65 g of the target compound (Compound 4). Compound 4 was a colorless transparent liquid, and the density at 20 was 1.74 gZcm ³ . The identification result of the compound 4 performed using NMR is shown. ^{For 19} F-NMR, compound 4 was used as is for analysis. In iH-NMR, the ester modification prepared according to the method described in Example 1 was analyzed.

¹⁹ F- NMR (solvent: None, reference material: the 〇_CF _{_{_₂}} CF ₂ CF ₂ CF ₂ 0 contained trace amounts to as one 125. 8 p pm in the product)

δ =-137. 9 p pm

[10 F, R f-[CF ₂ CH ₂ -0-P ₃ N _3- (OCH ₂ CF ₂ CF ₂ CF ₂ CF ₂ H) ₅ ]]

<5 = — 129. 5 ppm

(10 F, R f-[CF ₂ CH ₂ -0-P ₃ N _3- (O CH ₂ CF ₂ CF ₂ C Jl ₂ CF ₂ H) ₅ ])

δ =-124. 8 p pm [1 0 F, R f-[CF ₂ CH ₂ -0-P ₃ N _3- (O CH ₂ CF ₂ C F. ₂ CF ₂ CF ₂ H) ₅ ]]

(5 =-1 20 4 p pm ¹ [1 0 F, R f-[CF ₂ CH ₂ — O— P ₃ N ₃ — (〇CH ₂ C ₂ CF ₂ CF ₂ CF ₂ H) ₅ ]]

δ =-78.4 p pm,-80.4 p pm,

[2 F, R f-[CJ1 ₂ CH ₂ -O-P ₃ N ₃ — (OCH ₂ CF ₂ CF ₂ CF ₂ CF ₂ H)

Five] 〕

(5 =-77 9 ppm,-79.9 ppm

, [2 F, R f-C ₂ CH ₂ -0-CH ₂ CH (OH) CH ₂ OH]

6 =-80. 6 p pm, -82. 6 p pm

CO F, R f -CF. ₂ CH ₂ -OH3

m = 1 0 6, n = 10 1

¹ H—NMR (solvent: perfluorinated hexane, reference material: heavy water):

δ = 5. 26 p pm

C1H, R f -CF ₂ CH ₂ -0-CH ₂ CH (OCOCF ₃ ) CH ₂ OCOCF ₃ ], δ— 5.1 2 p pm

[0H, R f-CF ₂ CH ₂ -0-CH ₂ Cji (OCOC F ₃ ) CH ₂ ○ CH ₂ CH (○ COCF ₃ ) CH ₂ OCOCF ₃ ]

Test Example 1 Pound Rate Measurement

The compounds synthesized in Examples 1 to 3 (compounds 1 to 3) are each dissolved in X VERT 1 made by Du Pont. The concentrations of compounds 1 to 3 in this solution are all 0% by weight. A 35-inch diameter magnetic disk was immersed in this solution for 1 minute and pulled up at a speed of 4 mm. Then place this magnetic disk in a thermostat at 150 for 10 minutes to promote the adsorption of lubricant to the disk surface. After that, the average film thickness of the compound on the disk is measured with a Fourier Transform Infrared Spectrometer (FT-IR). Let this film thickness be f A. Next, this disc is immersed in Vertre 1-XF for 10 minutes, pulled up at a speed of 1 Omm Zs, and then allowed to stand at room temperature to evaporate the solvent. After this, the average film thickness of the compound remaining on the disk is measured by FT-IR. This film thickness is bA. , The pound rate, which is generally used, was adopted as an index indicating the strength of the adsorptivity with the disk. The pound rate is expressed by the following formula.

Bond rate (%) = 10 OXbZf,

For comparison, a compound in which at least one end of a perfluoropolyether having a hydroxyl group at both ends is a cyclophosphazene group substituted with an alkyl-dioxy group [Molecular manufactured by Matsumura Oil Research Co., Ltd.] Scophosphalol A 2 OH—2000], and perfluoropolyether having two hydroxyl groups at both ends (F omb 1 in Z tetr ao l -2000 S manufactured by S o 1 V ay S o 1 exis ) It was used. Morescophosphalol A 20H-2000 is hereinafter referred to as Compound 5, and Solfay Solexis Fomblin Z tetraol is hereinafter referred to as Compound 6. , R ¹ — OCH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m-(CF ₂ 0) n-CF ₂ CH ₂ —OH (Compound 5),

Where R ¹ is (n- CF ₃ C ₆ H ₄ 〇) ₅ — P ₃ N ₃ — (where — P ₃ N ₃ — is cyclic), m is 10.5, n is 10.1 It is.

HOCH _₂ CH (OH) CH ₂ -〇_CH _{_{_{2 CF 2 0 (CF 2 CF}}} 2 0) m - (CF 2 _{_{〇) n - CF 2 CH 2 0}} -CH 2 CH (OH) CH 2 OH ( Compound 6)

Where m is 10.1 and n is 109.

The pound rate of these compounds was measured. The results are shown in Table 1. From these results, in the perfluoropolyether of the present invention, an oxyalkylene containing a cyclophosphazene group substituted with a fluoroalkoxy group at one end and two or more hydroxyl groups at the other end It was confirmed that the perfluoropolyether compound having a group can form a lubricating layer bonded with a magnetic disk with a strong adsorption force. 【table 1】

Test Example 2 Measurement of decomposition resistance against aluminum oxide

Example 1 compound synthesized in 3 (compound 1-3), respectively 20 wt% of the A 1 ₂ 0 ₃ (MP Biomedicals Ltd., I CN A l um ina B , Ak t. I, average particle size ; Comparison of the thermal behavior in the presence of A 1 ₂ 0 ₃ was performed using a thermal analyzer (TGZ TDA) using a sample that was shaken vigorously after mixing 10 . test, the sample was placed 2 Omg an aluminum vessel, under a nitrogen atmosphere, and heated at a constant temperature of 250, was boss measure the weight reduction ratio of the compound after a predetermined time. for comparison, a 1 ₂ 0 The same thermal analysis was performed using 2 Omg of each of the compounds 1 to 3 without adding _3. Furthermore, in addition to the compounds 1 to 3, the compound 5 (morescophosphalol produced by Matsumura Oil Research Institute) A 2 OH-2000) and compound 6 (Som 1 Vay Solexis Fomblin Ztetr aol -20 00 S) were also used.

The results are shown in Table 2. As apparent from Table 2, in the perfluoropolyether of the present invention, a cyclophosphazene group substituted with a fluoroalkoxy group at one end and two or more hydroxyl groups at the other end par full O b polyether compound having Kishiarukiren group, like the compounds 5, a l ₂ 〇 ₃ weight loss less of promotion by is not observed, to be excellent in resistance to degradation was confirmed. From Table 1, it is clear that the compound 5 has low adsorptivity, and it can be confirmed that the compound of the present invention is effective in achieving both decomposition resistance and adsorptivity. [Table 2]

Example 5 Production of magnetic disk

Compounds 1 and 2 obtained in Examples 1 and 2 and Compound 6 for comparison are dissolved in Vertre 1—XF manufactured by DuPont. The concentration of the compound in this solution is 0 to 1% by weight. A 3.5-inch diameter magnetic disk was immersed in this solution for 1 minute and pulled up at a speed of 4 mmZs. Thereafter, it was dried at 150) for 10 minutes, and the film thickness of the applied compound was measured by FT-IR. The results are shown in Table 3.

[Table 3] Test Example 3 Measurement of lubricity of magnetic disk coated with lubricant

The lubricant performance test was carried out by measuring the change in the friction force by sliding the disk and head in contact with a spindle stand that was modified to measure the friction force on the head. The disc rotation speed was 90 rpm, and the maximum, minimum, and average frictional forces were output for each rotation. The quality of the test is determined by the fact that the maximum friction coefficient exceeds 5 OmN Judgment was made based on the time until endurance (durability). Contact sliding is regarded as an accelerated test for evaluating the sliding durability of floating magnetic disks.

The magnetic disk shown in Table 3 was used for the test. The results are shown in Table 4. As is apparent from Table 4, it was confirmed that the perfluoropolyether compound having a phosphazene ring of the present invention was excellent in sliding durability. [Table 4],

From the above results, in the perfluoropolyether of the present invention, a cyclophosphazene group substituted with a fluoroalkoxy group at one end and an oxyalkylene group containing two or more hydroxyl groups at the other end It was confirmed that the perfluoropolyether compound possessed had both high adsorbability and an effect of inhibiting decomposition, and that the magnetic disk having these compounds was excellent in sliding durability. Industrial applicability

In the perfluoropolyether of the present invention, a perfluoropolyether having a cyclophosphazene group substituted with a fluoroalkoxy group at one end and an oxyalkylene group containing two or more hydroxyl groups at the other end. Polyether compounds provide lubricants that can simultaneously achieve the two challenges of superior adsorption and lubricant decomposition, which were previously difficult to achieve. In addition, a magnetic disk using the compound of the present invention as a lubricant has an effect to withstand continuous rotation at high rotation.

Claims

The scope of the claims

1. A compound represented by the formula (I). , A-CH ₂ CF ₂ 0 (CF ₂ CF ₂ 0) m- (CF ₂ 0) n-CF ₂ CH ₂ -B (I) (where A is a group represented by the following formula (a) there. during formula B is a group represented. here the following formula (b), R is an Furuoroarukiru group C ₂ ~ _5, m is 0 or a real number of 1 to 40, n is 0 Or a real number from 1 to 40. p is a real number from 1 to 3.)

2. The compound according to claim 1, wherein m and n are real numbers of 4 to 21, and p is 1 or 2.

3. A lubricant containing a compound of formula (I).

A-CH ₂ CF ₂ 0- (CF ₂ CF ₂ 0) m- (CF ₂ 0) n-CF ₂ CH ₂ -B (I) (wherein A is a group represented by the formula (a) . during formula B is a group represented by the formula (b). here, R is a Furuoroarukiru group C ₂ ~ _5, m is 0 or 1 to 4 0 real, n represents 0 or 1 It is a real number of ~ 40. p is a real number of 1-3.

4. Lubricant according to claim 3, wherein m and n are real numbers from 4 to 21 and p is 1 or 2.

5. In a magnetic disk having at least a recording layer and a protective layer formed on a support and having a lubricating layer made of a compound having a perfluoropolyether structure on the surface, the lubricating layer is represented by the following formula (I): A magnetic disk characterized by containing a compound.

(a)

The magnetic disk according to claim 1, wherein m and n are real numbers of 4 to 21 and p is 1 or 2.