JPS58114331A - Production of magnetic recording medium - Google Patents

Abstract

PURPOSE:To make the lubricant layer on the magnetic layer of a magnetic recording medium durable and uniform by using perfluoroalkyl polyether as a layer of the lubricant, and forming said layer with the lubricant which is diluted in a high fluorinated soln. of temp. higher than specific value. CONSTITUTION:A magnetic coating dispersed with magnetic iron powder in a binder is coated on a non-magnetic substrate to form a magnetic layer; thereafter, perfluoroalkyl polyether is used as a layer of a lubricant on the surface of the magnetic layer. Said polyether is coated thereon after diluting the same to 0.2-5% with C7F16 or C6F16O of >=90 deg.C b.p. alone or with mixed solns. thereof. Thus, the perfluoroalkyl polyether of a low change rate of concn. is obtd., and the lubricant layer having high quality, high durability and small adsorptive power is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical field The present invention relates to a method for manufacturing a magnetic recording medium, in which a lubricant applied to the surface of a magnetic layer contains ether with a boiling point of 90%. This invention relates to a method of diluting the solution in a highly concentrated solution at a temperature of ℃ or higher.

(2) Background of the technology Recently, in response to the demand for increased recording density of magnetic media, efforts have been made to reduce the flying height of the magnetic head, and furthermore, the magnetic head and the medium come into contact and slide when starting and stopping. The so-called contact-start-styl method (C88 method) was adopted, and in order to improve the durability of the media against abrasion, a product called talite and kusu was manufactured by 2,47 companies. A commercially available lubricant having the following molecular formula is applied to the surface of the magnetic layer of the medium.

For the application of the above-mentioned clay and trash, various methods have been proposed, including a spin coating method (rotary coating method), a dipping method in which a medium is placed in a clay t-task, and a spray method using an appropriate spray gun. In each method, Krytox is rarely used as a stock solution (100%).
The product name for trichlorotrifluorethane C1ai is Freonte F), and a suspension obtained by diluting Krytox in a solvent such as a mixture of Freon Tlf and Infavir alcohol is used.

(3) Conventional technology and problems The above-mentioned Clyte V-kus is Freon! Complete Ki1 during r
However, since the boiling point of Freonte 1 is extremely low at approximately 48°C, it is difficult to maintain the concentration of the Talitox solution. When using the above-mentioned nine immersion method,
Maintaining concentration becomes a more serious problem due to the large volume of solution and the wide opening of the container. Before, in the spin code method, 4
, Freon! Since r evaporates quickly, even if the solution is dropped onto the medium, it is difficult to spread it uniformly over the entire surface, and in most cases, a rounding spin is used to achieve uniformity;
- After tinging, wiping (buffing) or heat diffusion process is required.

All of these circumstances have led to an increase in the production of magnetic media)
This, in turn, becomes a factor in lowering the yield.

(4) Purpose of the Invention In view of the above-mentioned problems of the prior art, it is an object of the present invention to provide a method for manufacturing a magnetic medium in which the concentration of a tattoo tox solution can be easily maintained and has excellent uniform coating properties.

(5) Structure and object of the invention According to the present invention, a magnetic paint made by dispersing magnetic fine powder in a binder is applied to a non-magnetic substrate,
0.5~1.2 II! In the method for producing a magnetic recording medium, the lubricant layer comprises forming a magnetic layer and then applying a lubricant to the surface of the magnetic layer, wherein the lubricant layer comprises /terfluoroalkyl diether having a boiling point of 90°C or higher. Provides a method for obtaining by diluting in solution. Therefore, the molecular formula of the highly fluorinated liquid is C7F14 or C,F,40
This is a single solution and a mixed solution, and the dilution concentration of per-70roalkyl ether in this solution is 0.2 to 5-5.
It is.

(6) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

The inventor of the present application determined that the problems experienced when using currently commercially available 7 Leon 〒r were caused by the rapid evaporation rate of 7 Leon, and in order to solve the above-mentioned 9 problems, After repeated experiments with various solvents, we determined the relationship between the boiling point and the change in Krytox solution concentration over time, as shown in Figure 1. In the figure, the horizontal axis shows the boiling point temperature (C) of the solution, and the vertical axis shows the daily O concentration change rate in -.

The range indicated by the arrow in the figure is within the range of acceptable m, but when making this determination, it is judged that it is difficult to manage practically if the concentration remains unchanged for more than 3-7 days, and 3-/Japan and America grooves are passed. . The point where an arrow is attached to the circle at the upper left of the coordinates in the figure indicates the case where Freon TF is used, and the rate of change in degree is s01/day or more. In addition, in this experiment, we measured the change in concentration when we filled a 50-liter container with 5 tons of each solvent (2) Y) and left it at 25℃ for 1 day, The three points within the range are data based on the method of the present invention.

Next, the evaluation results of applicability are shown in Fig. 2.
Performed by both spin coating method and dipping method9,
Regarding the applicability, which is indicated by a score on the vertical axis of the figure, a score of 9 or less means that the quality is not stable, or the next process requires puffing.
t9 was determined to be unsuitable because it folds the heat diffusion process, and those with a score exceeding 9 points were judged as passing.

Specifically, after the solvent evaporates, if the Kutite and Kusu appear as a continuous film and have good uniformity, the score is 10, and if the Kutite and Kusu look uniformly granular, the score is 5. If the Krytox is not applied evenly, 3-point binding is required.)
The intermediate value of these point distributions can be determined as appropriate. In the same figure, the horizontal axis indicates the boiling point temperature of the solution (℃), and the arrow indicates l1
II indicates passing, square marks indicate those obtained by the dipping method, and circle marks indicate those obtained by the spin code method.

In both the spin code method and the dipping method, in order to coat a disk with a diameter of approximately 36# (14 inches) with a coating thickness of 30 degrees, the solution concentration and coating conditions (e.g., rotation speed in spin coating, disk pulling in the dipping method) 100% boiling point according to the present invention.
If a solvent at 0.11°C can be used, the CSS of the Winchester Taki head is shown in Figure 3. Both the coating method and the dipping method were used, and the coating conditions were determined to be optimal for each, and the coating was performed by selecting the coating conditions.Therefore, wiping and thermal diffusion J6m were not performed. , The vertical axis shows the number of durability tests in 10,000 units.
More than 10,000 times.

Furthermore, a pressurized winch and starch head of 101 was placed on top of the above-mentioned disc at 24° C. and a temperature of 7 G for 24 hours.
Figure 4 shows the results of measuring the adhesion force (head stick) generated between the head and disk after the head and disk were left under these conditions. is the concentration of thalitosix solution (ls), and the vertical axis is the adsorption force (J
F), The range indicated by the arrow indicates a pass with a suction force of 5Jll or less.The square mark and circle mark are the same as in Figure 3.For the 0 pass line, when the suction force is 5# or less, the head and de(splash) Since no scratches were observed on either side, the test piece s1 or lower was considered to be passed.

Based on the above-mentioned results, it was determined that the practical concentration at which stable quality can be obtained when coating kleit and kurite using the solvent according to the present invention is 0.2 to OSS. In other words, if the dilution is too light within this range, coating conditions that provide sufficient durability cannot be obtained, whereas if the dilution is too thick, the adsorption force becomes too strong, making it unsuitable for practical use.

(7) Detailed explanation of the invention: When using the method of the present invention, a solution of Krytox with a low rate of change in concentration can be obtained, and when this solution is used, it is possible to obtain a high-quality, highly durable solution. , a lubricant layer with low adsorption force can be obtained, which greatly contributes to improving the reliability of magnetic media.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between the boiling point and the change in temperature of the Talitox solution over time; Figure 2 is a diagram showing the OIk properties of the solution; Concentration and C
FIG. 4 is a diagram showing the relationship between the durability of the 8S head and the adsorption force of the CSG head. Patent applicant Fujitsu Limited

Claims (3)

[Claims] (1) Manufacturing a magnetic recording medium by coating a non-magnetic substrate with a magnetic paint made by dispersing magnetic iron powder in a binder to form a magnetic layer, and then coating the surface of the magnetic layer with a lubricant. A method for producing a magnetic recording medium, characterized in that the wrinkle lubricant layer is formed by diluting l-lyether in d-fluoroalcohol with a boiling point of 90° C. or more in a highly fluorinated solution. (2) The molecular formula of the high concentration solution is '7'14 is Cs'
, p or a mixed solution of the magnetic recording medium according to claim 1. (3) /f-fluoroalkyl into high fluoride solution
2. The method of manufacturing a magnetic recording medium according to claim 1, wherein the degree of dilution of the riether is from 0.2 to 5.