Abstract: A lubricant which does not splash easily and has an improved property of slidableness, and a magnetic disk using the lubricant are provided. A magnetic disk apparatus featuring a prolonged service life of a stable operation and an excellent record reproduction property is provided by installing the above magnetic disk. The lubricant of the invention contains perfluoropolyether expressed by the following general formula, in which a component of its molecular weights less than 1000 is smaller than 10 wt. %, a component of its molecular weights not less than 7000 is smaller than 15 wt. %, a ratio between a weight average molecular weight and a numeric average molecular weight is 1.5 or less, and a substitution ratio of its terminal functional group is not less than 90%: R1—CF2O—[—(CF2CF2O)—m—(CF2O)—n—]—CF2—R2??(1), where R1 and R2 are univalent organic groups, m and n are positive integers.

Abstract: A lubricant which does not splash easily and has an improved property of slidableness, and a magnetic disk using the lubricant are provided. A magnetic disk apparatus featuring a prolonged service life of a stable operation and an excellent record reproduction property is provided by installing the above magnetic disk. The lubricant of the invention contains perfluoropolyether expressed by the following general formula, in which a component of its molecular weights less than 1000 is smaller than 10 wt. %, a component of its molecular weights not less than 7000 is smaller than 15 wt. %, a ratio between a weight average molecular weight and a numeric average molecular weight is 1.

Abstract: A lubricant which does not splash easily and has an improved property of slidableness, and a magnetic disk using the lubricant are provided. A magnetic disk apparatus featuring a prolonged service life of a stable operation and an excellent record reproduction property is provided by installing the above magnetic disk. The lubricant of the invention contains perfluoropolyether expressed by the following general formula, in which a component of its molecular weights less than 1000 is smaller than 10 wt. %, a component of its molecular weights not less than 7000 is smaller than 15 wt. %, a ratio between a weight average molecular weight and a numeric average molecular weight is 1.5 or less, and a substitution ratio of its terminal functional group is not less than 90%: R1—CF2O—[—(CF2CF2O )—m—(CF2O)—n—]—CF2—R2  (1), where R1 and R2 are univalent organic groups, m and n are positive integers.

Abstract: A thin film magnetic disc in which dot-like scattered bumps, made of a material different from that of the protective layer, are formed on the protective layer, and a lubricant layer is formed on the surfaces of the protective layer and the scattered bumps. A protective layer excellent in strength and disk durability is obtained by using a material different from that of the bumps. The functions of the protective layer and scattered bumps are separated from each other and make full use of the different materials. Such a protective layer is effective to reduce spacing between a head and the disc.

Abstract: The present invention is aimed at providing a magnetic disk and a magnetic disk apparatus both of which have a high performance lubricating film which makes continuous sliding endurance and low adhesiveness compatible, and a lubricating film having a self repairing function which makes it possible to recombine scratched off lubricating agent from the magnetic disk surface by sliding with a head onto the magnetic disk surface. The lubricating film comprises at least two kinds of lubricating agents each of which forms an individual layer, the layers being laminated. An adhesion enhancing layer is formed between a magnetic film and a lubricating agent at the surface of the magnetic disk, and the adhesion enhancing layer is fixed onto the magnetic film surface. Then, the adhesion enhancing layer and the lubricating agent are combined.

Abstract: The magnetic recording medium includes at least a substrate, a magnetic film formed on the substrate for storing data, a protective film and a lubricant film. The protective film has two regions of a predetermined pattern each having a different surface energy. The lubricant film including polar groups is formed on the protective film including the regions. The degree of adhesion of the lubricant film to the protective film is thus changed at the two regions each having a different surface energy so that the lubricant film can be prevented from being scattered.

Abstract: A highly reliable rotary magnetic recording medium has a lubricating film layer on its surface, the lubricating film layer being composed of fluoropolyether having at least two acidic functional groups in one molecule as a lubricant and fluoropolyether having at least two basic functional groups in one molecule as another lubricant, where a stable network structure is formed on the surface of the magnetic recording medium by an appropriate combination of the lubricant having the acidic groups at the terminal ends of lubricant molecule and the lubricant having the basic groups at the terminal ends of lubricant molecule.

Abstract: A coating type, magnetic disk is produced by applying a magnetic paint containing magnetic powders in a dispersed state to a non-magnetic substrate, thereby forming a magnetic recording film thereon, and applying surface waves to the magnetic recording film in an undried state. By applying the surface waves to the magnetic recording film, dispersibility and orientation of the magnetic powders are improved and a longitudinally oriented, coating type magnetic disk with distinguished electromagnetic properties, such as a high S/N ratio, etc. can be obtained.

Abstract: Disclosed herein are a magnetic recording medium comprising a surface treatment layer provided on the surface of a magnetic coating film by use of a novel surface treatment agent capable of bonding to both magnetic particles and a binder in the magnetic coating film, and a process for producing the magnetic recording medium.It is possible to realize, with good productivity, a magnetic recording medium having excellent wear resistance and high reliability.

Abstract: A magnetic recording medium comprising a substrate, a ferromagnetic thin film formed on the substrate, and a protective film formed directly on the ferromagnetic think film, and a process for producing such magnetic recording medium. The expression "formed directly" refers to the technique for forming the protective film on the ferromagnetic thin film so that the interface therebetween is free from contamination by, for instance, conducting the protective film formation under the vacuum used when forming the ferromagnetic thin film.

Abstract: A method for magnetic orientation of a magnetic recording medium using Meissner effect of a superconductor and a system therefor and a magnetic recording medium produced thereby. The magnetic particles of plate hexagonal barium ferrite in the magnetic coating are allowed to orient in the longitudinal direction thereof so that a magnetic recording medium having a magnetic orientation in such direction with the magnetic particles can be obtained.

Abstract: A fluorine-containing isocyanate derivative, wherein the isocyano group of the fluorine-containing isocyanate is protected, a fluorine-containing polymer having at least one acylazido group, a process for producing an information recording medium by applying a lubricant comprising the fluorine-containing isocyanate derivative or the fluorine-containing polymer having at least one acylazido group to a magnetic layer formed on a substrate directly or through an underlayer, or to a protective layer formed on the magnetic layer, then reproducing or forming an isocyano group and subjecting the isocyano group to polymerization, thereby forming a fluorine-containing isocyanate polymer layer, an information recording medium produced according to the process and an apparatus for information recording, using the information recording medium are disclosed.

Abstract: A magnetic recording medium comprising a substrate and, formed thereon, a magnetic layer comprised of magnetic particles bonded to each other with a thermosetting binder can be improved with respect to the durability by forming a number of fine pores in the magnetic layer and impregnating the fine pores with a lubricant. Particularly, when the fine pores have a diameter of 0.2 .mu.m or less and a rate of the fine pore in area of 3 to 30%, the durability can be improved while maintaining the noise during the recording and reproduction of information on a low level. In preparing the magnetic recording medium having such fine pores, it is preferred that an easily thermal-decomposable additive, such as polyalkylene oxide, be added to a magnetic layer forming paint.

Abstract: A magnetic recording medium comprising a substrate and, formed thereon, a magnetic layer comprised of magnetic particles bonded to each other with a thermosetting binder can be improved with respect to the durability by forming a number of fine pores in the magnetic layer and impregnating the fine pores with a lubricant. Particularly, when the fine pores have a diameter of 0.2 .mu.m or less and a rate of the fine pore in area of 3 to 30%, the durability can be improved while maintaining the noise during the recording and reproduction of information on a low level. In preparing the magnetic recording medium having such fine pores, it is preferred that an easily thermal-decomposable additive, such as polyalkylene oxide, be added to a magnetic layer forming paint.

Abstract: A magnetic recording medium is prepared by applying a magnetic paint containing at least magnetic particles and a thermally curable binder to a substrate, thermally curing the applied magnetic paint, thereby forming a magnetic film, and impregnating micropores formed in the magnetic film with a lubricant, where the magnetic paint further contains a poly(alkyleneoxide)-grafted binder, and the grafted poly(alkyleneoxide) moiety is thermally decomposed during the thermal curing, thereby forming the micropores in the magnetic film. A large number of micropores having a pore size of not more than 0.1 .mu.m are formed in the magnetic film, and a magnetic disk of high durability with less noises and errors during the recording and reproduction can be obtained.

Abstract: A magnetic recording medium comprising a substrate, a ferromagnetic thin film formed on the substrate, and a protective film formed directly on the ferromagnetic thin film, and a process for producing such magnetic recording medium. The expression "formed directly" refers to the technique for forming the protective film on the ferromagnetic thin film so that the interface therebetween is free from contamination by, for instance, conducting the protective film formation under the vacuum used when forming the ferromagnetic thin film.

Abstract: A magnetic recording medium which has a magnetic coating film that contains magnetic particles in a binder and which further has a lubricating layer formed on the magnetic coating film. The magnetic coating film has a surface that is processed with both a fluorinated surface treatment agent that bonds to the magnetic particles and a fluorinated surface treatment agent that bonds to the binder. The magnetic recording medium exhibits markedly improved sliding strength when the surface treatment agents and the lubricant have similar molecular structures. It is particularly preferred that the fundamental skeleton in the molecular structure of the surface treatment agents and the lubricant consists of a perfluoropolyether chain.

Abstract: This invention relates to a magnetic recording medium comprising a magnetic recording film formed on a substrate directly or with a protective layer therebetween, characterized in that a surface treatment layer made of a reaction product of an azide compound is provided on the magnetic recording film, and preferably a lubricative material layer is further provided on the surface treatment layer. The surface treatment agent is covalently bonded to the surface of the magnetic recording film with an aid of nitrene to improve the durability of the magnetic recording film.

Abstract: The invention provides magnetic recording media such as magnetic disks, etc., with an improved lubricant composition of perfluoroalkylpolyether with a polar terminal group and perfluoroalkylpolyether without a polar terminal group on the surfaces.

Abstract: A composition of magnetic recording media consisting of a ferromagnetic powder such as .gamma.-Fe.sub.2 O.sub.3, a binder and single crystal alumina as a reinforcing agent. Single crystal .alpha.-alumina is preferably used as said single crystal alumina and its amount is preferably from 1 to 20% by weight based on the magnetic powder.