Abstract: Provided is a magnetic disk comprising a lubricating layer formed of a lubricant. The lubricant constituting the lubricating layer has excellent properties, for example, excellent fluidity, surface energy, and CFT properties. By virtue of the excellent properties, the magnetic disk has a high level of reliability despite a low flying height of a magnetic head due to a recent rapid increase in recording density and a very severe environment resistance requirement due to diversification of applications. The magnetic disk comprises a substrate and at least a magnetic layer, a protective layer, and a lubricating layer provided in that order over the substrate.

Abstract: Disclosed is a magnetic disk which has a lubricant layer with excellent heat resistance and high adhesiveness and is free from fly-stiction failure or corrosion failure even at an extremely low flying height of 10 nm or lower. Also disclosed is a magnetic disk which has a lubricant layer with good thermal properties and can exert a stable action over a wide temperature range. The magnetic disk comprises a substrate (1), and a magnetic layer (3), a carbon-containing protective layer (4) and a lubricant layer (5) provided on the substrate (1), wherein the lubricant layer (5) contains a magnetic disk lubricant comprising a compound having a phosphazene ring and two or more hydroxyl and/or carboxyl groups in the molecule.

Abstract: In a magnetic disk has at least a magnetic layer, a carbon-based protective layer, and a lubricating layer formed in this order over a substrate, the lubricating layer contains a lubricant compound including a compound which has a perfluoropolyether main chain in a structure thereof, an aromatic group located at a position except each end of a molecule thereof, and a polar group at each end of the molecule.

Abstract: A magnetic disc is provided with a magnetic layer, a protection layer and a lubrication layer in this order on a substrate. After successively forming the magnetic layer and the protection layer on the substrate, the protection layer is exposed to plasma under normal pressure, then, the lubrication layer is formed on the protection layer. The plasma is generated in at least one kind of gas selected from among nitrogen gas, argon gas, oxygen gas, and fluorine hydrocarbon gas. The protection layer is a hydrogenated carbon protection layer.

Abstract: On manufacturing a magnetic disk having at least a magnetic layer (60), a protective layer (70), and a lubricating layer (80) formed in this order over a substrate (10), the lubricating layer is formed by using a coating solution in which a perfluoropolyether compound having a perfluoropolyether main chain and a hydroxyl group in a structure thereof is dispersed and dissolved in a fluorine-based solvent having a boiling point of 90° C. or more.

Abstract: A cooling fan includes: a hub; a plurality of cooling vanes provided along an outer circumference of the hub; and an annular connector for connecting the cooling vanes. The hub is provided with a through hole that axially penetrates the hub. A first cover on a case for covering an outward side of the cooling fan is provided with a first outer-air intake. A second cover for partitioning between the cooling fan and a crankcase and for covering an inward side of the cooling fan is provided with a second outer-air intake. With this arrangement, even when one outer-air intake (for instance, the first outer-air intake) adjacent to where the cooling vanes are provided is clogged by a large amount of dust generated during operations, the cooling vanes can breathe from the non-clogged other outer-air intake (for instance, the second outer-air intake) through the through hole, thereby restraining reduction in air flow.

Abstract: A muffler includes a muffler body disposed on a lower portion of an engine and a passage that extends upward from the muffler body and is opened in an upper front portion of a chain saw body. Thus, exhaust gas can be discharged forward from the chain saw body, so that exhaust sounds can be dispersed forward. Consequently, the exhaust sounds propagated to an operator can be reduced and therefore a work environment can be improved. Also, since exhaust gas is discharged after the exhaust gas passes through a long passage extending upward from the muffler body, the exhaust gas can be cooled down. Accordingly, in the chain saw body typically covered with a synthetic-resin case in which exhaust outlets are formed on positions corresponding to outlets of the passage, peripheries of the exhaust outlets can be prevented from being discolored by heat of exhaust gas.

Abstract: A lubricant for magnetic disks which can form a lubricating layer having a reduced thickness while attaining a high coverage and is excellent in heat resistance and adhesion to a protective layer. The lubricant for magnetic disks comprises a perfluoropolyether compound in which the relationship between the number-average molecular weight and the standardized value of the number of hydroxy groups contained in the molecule satisfies the following: the number-average molecular weight is in the range of 1,000-6,000; the standardized value of the number of hydroxy groups contained in the molecule is 180 or higher; and the compound is in a region located below the line connecting the point where the number-average molecular weight is 1,000 and the standardized value of the number of hydroxy groups in the molecule is 400 to the point where the number-average molecular weight is 6,000 and the standardized value of the number of hydroxy groups in the molecule is 1,600.

Abstract: In order to obtain a magnetic recording disk that exhibits high reliability even if the flying height of a magnetic head becomes very narrow, a lubricant is specified in terms of both molecular structure and quantitative data. That is, a lubricating layer 14 of the magnetic recording disk 1 is formed by a lubricant which contains perfluoropolyether compounds represented by the following chemical formula (Chemical Formula 1) and which has a first component content of 71.7%, a second component content of 15.7%, a third component content of 11.7%, a fourth component content of 0.3%, and a fifth component content of 0.

Abstract: In a magnetic recording disk 1 including a magnetic layer 12, a protective layer 13, and a lubricating layer 14, the lubricating layer 14 is made from a lubricant prepared from a composition. The weight change of the lubricant ranges from ?20% to ?50% at 300° C. in the case where the lubricant is subjected to thermogravimetric analysis in such a manner that the lubricant is heated from 40° C. to 500° C. at a heating rate of 10° C./min. The lubricant has a maximum peak at about 300° C. in the case where the lubricant is subjected to differential thermal analysis in the same manner as described above. The lubricant can be quantitatively measured for heat resistance. Therefore, a magnetic recording disk exhibiting stable performance at high temperatures and a method for manufacturing such a magnetic recording disk can be obtained.

Abstract: On producing a lubricant which is used in making a lubrication layer included in a magnetic disk from the lubricant, a phosphorus-containing compound is removed from a raw-material lubricant including the phosphorus-containing compound to produce the lubricant. The magnetic disk includes a substrate on which at least a magnetic layer, a protection layer, and the lubrication layer formed by the use of the lubricant are successively formed.

Abstract: Disclosed is a magnetic disk which has a lubricant layer with excellent heat resistance and high adhesiveness and is free from fly-stiction failure or corrosion failure even at an extremely low flying height of 10 nm or lower. Also disclosed is a magnetic disk which has a lubricant layer with good thermal properties and can exert a stable action over a wide temperature range. The magnetic disk comprises a substrate (1), and a magnetic layer (3), a carbon-containing protective layer (4) and a lubricant layer (5) provided on the substrate (1), wherein the lubricant layer (5) contains a magnetic disk lubricant comprising a compound having a phosphazene ring and two or more hydroxyl and/or carboxyl groups in the molecule.

Abstract: The present invention provides a lubricant for forming a lubricating layer which is useful in preventing fly and stiction and/or corrosion at an extremely small flying height of 10 nm or less, which is prevented from migrating at a high rotational speed of 5400 rpm or more, which has high adhesion, and which is suitable for a load/unload method. A crude lubricant containing at least one perfluoropolyether is degassed and then purified. Alternatively, a liquid crude lubricant containing at least one perfluoropolyether is purified by vaporizing the crude lubricant and then liquefying the vapor of the perfluoropolyether within a distance less than the mean free path of molecules of the perfluoropolyether. A magnetic disk is prepared in such a manner that a carbonaceous protective layer is formed above a substrate and a lubricating layer is formed on the protective layer using of the lubricant. The lubricant contains the perfluoropolyether and has a molecular weight distribution of 1.3 or less.

Abstract: A magnetic recording disk having a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a perfluoropolyether compound having an end moiety containing a phosphazene ring and a perfluoropolyether compound having an end moiety containing a hydroxyl group, or the lubricant layer containing a perfluoropolyether compound having an end moiety containing a hydroxyl group on the protective layer side and a perfluoropolyether compound having an end moiety containing a phosphazene ring on the other surface side, and a process for manufacturing each of these magnetic recording disks.

Abstract: A magnetic recording disk having a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a perfluoropolyether compound having an end moiety containing a phosphazene ring and a perfluoropolyether compound having an end moiety containing a hydroxyl group, or the lubricant layer containing a perfluoropolyether compound having an end moiety containing a hydroxyl group on the protective layer side and a perfluoropolyether compound having an end moiety containing a phosphazene ring on the other surface side, and a process for manufacturing each of these magnetic recording disks.

Abstract: Disclosed is a method of manufacturing magnetic disks, comprising a magnetic layer, a protective layer, and a lubricating layer on a substrate. In the process, a lubricant alpha comprising a compound denoted by chemical formula HO—CH2—CH(OH)—CH2—O—CH2—CF2(—O—C2F4)p-(O—CF2)q-O—CF2—CH2—O—CH2—CH(OH)—CH2—OH wherein p and q are natural number, and a compound denoted by chemical formula HO—CH2—CF2(—O—C2F4)m-(O—CF2)n-O—CF2—CH2—OH wherein m and n are natural number, is fractionated by molecular weight to prepare a lubricant a having a weight average molecular weight (Mw) of from 3,000 to 7,000 and a molecular weight dispersion of less than or equal to 1.2; a lubricant beta comprising a compound denoted by the chemical formula HO—CH2—CF2(—O—C2F4)m-(O—CF2)n-O—CF2—CH2—OH wherein m and n are natural number, is fractionated by molecular weight to prepare a lubricant b having a weight average molecular weight (Mw) of from 2,000 to 5,000 and a molecular weight dispersion of less than or equal to 1.

Abstract: A magnetic recording disk has a high-adhesion lubricant layer that permits an operation at an extremely low level of flying height of 12 nm or less without troubles and which is capable of preventing the migration at a high-speed rotation, and comprises a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a compound (A) of the general formula (I), wherein each of p and q is an integer of 1 or more, and a compound (B) having a perfluoropolyether main chain having two end moieties each of which contains a carbon atom or an oxygen atom to which a hydroxyl-containing hydrocarbon group that optionally contains ether bond(s) is bonded, and a process for the manufacture thereof is provided.

Abstract: On producing a lubricant which is used in making a lubrication layer included in a magnetic disk from the lubricant, a phosphorus-containing compound is removed from a raw-material lubricant including the phosphorus-containing compound to produce the lubricant. The magnetic disk includes a substrate on which at least a magnetic layer, a protection layer, and the lubrication layer formed by the use of the lubricant are successively formed.

Abstract: A semiconductor device including memory cells such as flip-flops, RAMs or SRAMs is powered on, and first logic signals of Hi or Lo output from the respective memory cells are obtained. A combination of the logic signals is used as a unique identification code for identifying a semiconductor device.

Abstract: A magnetic recording disk having a substrate, a magnetic layer formed on the substrate, a protective layer formed on the magnetic layer and a lubricant layer formed on the protective layer, the lubricant layer containing a perfluoropolyether compound having an end moiety containing a phosphazene ring and a perfluoropolyether compound having an end moiety containing a hydroxyl group, or the lubricant layer containing a perfluoropolyether compound having an end moiety containing a hydroxyl group on the protective layer side and a perfluoropolyether compound having an end moiety containing a phosphazene ring on the other surface side, and a process for manufacturing each of these magnetic recording disks.