321results about "Magnetic layer protection" patented technology

Disclosed herein are blowing agents comprising fluorocarbons and / or hydrofluorocarbons useful in foamable compositions. Also disclosed are methods for forming a foam comprising the aforementioned blowing agents.

In a magnetic disk that 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.

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 formulaHO—CH2—CH(OH)—CH2—O—CH2—CF2(—O—C2F4)p-(O—CF2)q-O—CF2—CH2—O—CH2—CH(OH)—CH2—OHwherein p and q are natural number,and a compound denoted by chemical formulaHO—CH2—CF2(—O—C2F4)m-(O—CF2)n-O—CF2—CH2—OHwherein 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 formulaHO—CH2—CF2(—O—C2F4)m-(O—CF2)n-O—CF2—CH2—OHwherein 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 1.2;a lubricant c comprising a mixture of lubricants a and b is prepared; anda film of lubricant c is formed on a protective layer provided on a substrate to form a lubricating layer. A magnetic disk comprising a magnetic layer, a protective layer, and a lubricating layer on a substrate, in which the lubricating layer has been formed on the protective layer is also enclosed.

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 0.6%:X—OCH2CF2—(CF2O)m(C2F4O)n—CF2OCH2O—X  (Chemical Formula 1)m, n=9 to 11first component: X=X1=CH2CH(OH)CH2OHsecond component: X=X2=CH2CH(OH)CH2OCH2CH(OH)CH2OHthird component: X=X3=Hfourth component: X=X4=CF3 fifth component: X=X5=CF2Cl.

In a magnetic disk having a magnetic layer, a protection layer, and a lubrication layer formed on a substrate in this order, a surface free energy γS of a surface of the magnetic disk derived by an extended Fowkes equation is greater than 0 and no greater than 24 mN / m. γSd (dispersion force component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 17 mN / m, γSp (dipole component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 1 mN / m, and γSh (hydrogen bonding force component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 6 mN / m.

A perpendicular magnetic recording medium, including a suitable lubricating layer with sufficient durability, moisture resistance, and contamination resistance and also maintaining an R / W characteristic. The perpendicular magnetic recording medium 100 includes a magnetic recording layer 122, a medium protective layer 126, and a lubricating layer 128 in this order on a base 110. The medium is made using a CF bond density measuring step of measuring a CF bond density of a lubricant; and a lubricating layer forming step of forming a lubricating layer with the lubricant when the measured CF bond density is 2.0×1022 to 2.7×1022 atoms / cm3.

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.

An object of the present invention is to provide a perpendicular magnetic recording medium including a suitable lubricating layer with sufficient durability, moisture resistance, and contamination resistance and also maintaining an R / W characteristic. In a typical structure of the present invention, a method of manufacturing a perpendicular magnetic recording medium 100 including a magnetic recording layer 122, a medium protective layer 126, and a lubricating layer 128 in this order on a base 110 includes: a CF bond density measuring step of measuring a CF bond density of a lubricant; and a lubricating layer forming step of forming a lubricating layer with the lubricant when the measured CF bond density is 2.0×1022 to 2.7×1022 atoms / cm3.

Disclosed is a method for removing residue from a surface comprising: contacting the surface with a composition comprising at least one unsaturated fluorinated hydrocarbon selected from the group consisting of compounds having the formula E- or Z-R1CH═CHR2, wherein R1 and R2 are, independently, C1 to C6 perfluoroalkyl groups, or C1 to C6 hydrofluoroalkyl groups, and recovering the surface from the composition.

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, anda 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.

This invention relates to cleaning compositions comprising unsaturated fluorinated hydrocarbons. The invention further relates to use of said cleaning compositions in methods to clean, degrease, deflux, dewater, and deposit fluorolubricant. The invention further relates to novel unsaturated fluorinated hydrocarbons and their use as cleaning compositions and in the methods listed above.

A magnetic disk comprises a magnetic layer and a protective layer sequentially formed on a disk-shaped substrate and has a principal surface to which data is recorded, and a side surface portion both of which are coated with the protective layer. The protective layer on the side surface portion is thinner than the protective layer on the principal surface. Preferably, the side surface portion includes a side wall surface, and a chamfered surface lying between the side wall surface and the principal surface, and at least the protective layer on the chamfered surface is thinner than the protective layer on the principal surface.

Disclosed herein are blowing agents comprising fluorocarbons and / or hydrofluorocarbons useful in foamable compositions. Also disclosed are methods for forming a foam comprising the aforementioned blowing agents.

The fabrication of the overcoat layer starts with a low energy ion beam to avoid magnetic layer implantation problems, followed by higher deposition energies where the higher energy atoms are implanted into the previously formed lower energy overcoat layer, rather than the magnetic layer. The energy gradient ion beam deposition process therefore results in a thin overcoat layer that is denser than a comparable layer formed by low energy magnetron sputtering, and which overcoat layer provides good mechanical and corrosion protection to the magnetic layer, without degrading the magnetic properties of the magnetic layer.