JPH012874A - Surface polishing tape for magnetic recording media - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used to ensure the smoothness and surface cleanliness of the surface of the magnetic recording medium when manufacturing magnetic recording media such as flexible magnetic disks and magnetic tapes. Regarding surface polishing tape.

[Conventional technology]

In recent years, there has been a growing demand for higher density magnetic recording media such as flexible magnetic disks and magnetic tapes, and for this reason, it is desired to develop design techniques for ultra-smooth media. A common means of achieving this is abrasive particles.

Magnetic paint is obtained by mixing and dispersing a binder as a main component and various additives including a dispersant using a dispersing machine such as a sol mill, and uniformly coating the resulting paint onto a substrate such as a polyester film. A method is used to remove minute protrusions on the surface of the magnetic layer using a surface polishing tape for recording media.

[Problem that the invention seeks to solve]

However, even if such a polishing tape is used to polish the surface of a magnetic recording medium, it is difficult to completely remove minute polishing debris that adheres to the surface, and as a result, missing errors and extra errors may occur. ,Also,
There was a problem in that scratches and other flaws occurred on the surface of the magnetic recording medium.

Furthermore, if a magnetic recording medium whose surface has been polished using a conventional polishing tape as described above is used for a long period of time, minute polishing debris remaining on the surface will accumulate on the magnetic head, causing pitting/greasing errors and extra errors. There were problems in ensuring reliable track quality.

As a solution to this problem, there is a method of using a dedicated cleaning non-woven tape in order to increase the degree of adhesion of the media surface after polishing, but even if cleaning is performed using the cleaning non-woven tape, it will not adhere to the surface. It is difficult to completely remove minute polishing debris, and as a result, it has been difficult to obtain a magnetic recording medium with excellent track quality.

The present invention has been made in view of the current situation. That is, the second object of the present invention is to provide an abrasive tape that is effective in obtaining a magnetic recording medium that does not cause missing errors or extra errors, has excellent track quality, and has excellent reproducibility. be.

[Means for solving problems]

According to the present invention, an abrasive layer containing abrasive particles, a binder, and a dispersant as constituent components, and a nonwoven fabric layer consisting of a fiber component are provided on a support. The purpose of the present invention is to use a surface polishing tape for a magnetic recording medium, which is characterized in that it is formed on a magnetic recording medium.

[Effect]

In the present invention, by forming the polishing layer and the non-woven fabric layer alternately in the longitudinal direction of the polishing tape, the fine polishing debris generated during surface polishing is held in the non-woven fabric layer and prevented from adhering to the surface of the magnetic recording medium. do.

〔Example〕

Next, two embodiments of the present invention will be described with reference to the drawings.

Referring to FIGS. 1 and 2, a surface abrasive tape for a magnetic recording medium according to an embodiment of the present invention has 2 a support 1 made of, for example, a polyester film.

It has a polishing layer 2 and a nonwoven fabric layer 3 formed on the support 1. The polishing layer 2 contains polishing particles, a binder, a dispersant, and the like as constituent components.

As the support 1 used in the present invention, any of polyethylene terephthalate, acetate, I-limide, etc. may be used.

The abrasive particles may be fine powders with a Mohs hardness of 6 or more,
Fused alumina, silicon carbide, chromium oxide.

Examples include α-iron oxide, diamond, silicon oxide, titanium oxide, and the like. The average particle diameter of the fine powder is 0.01 to 10
It may be within the range of μm, preferably 0.3 to 3 μm.

As the binder, conventional commercially available resins can be used. For example, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl propionate copolymer, vinyl chloride-acrylic acid ester copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, l?
IJ vinyl butyral resin, acrylonitrile-butadiene co-polymer.

Examples include polyurethane resin, phenoxy resin, urethane resin, etc., and these resins may be used alone.

Also, two or more types of resin may be used in combination.

As a dispersant, use an alkyl betaine compound.

Examples include alkyl phosphate esters, higher fatty acids having carbon IB of 12 to 18, and alkali metal salts thereof. The amount of the dispersant added is 0.1 to 10wt relative to the abrasive particles.
%, preferably 1 to 3 wt%.

As the fiber component of the nonwoven fabric layer 3, many conventionally known fiber components can be used. For example, rayon, polyester.

Examples include polypropylene, and these fiber components may be used alone or in combination.

Any method may be used to form the polishing layer 2 and the nonwoven fabric layer 3 alternately in the longitudinal direction of the polishing tape.
For example, after forming a discontinuous layer of the polishing layer 2 on a support by a gravure coating method, the polishing layer 2 is masked, an adhesive is poured into the recesses on the substrate, and then a defibrated fiber component is sprayed.

There is a method in which the fiber components are then fixed and smoothed by calendering. The number of polishing layer 2 per inch is 30
~70 pieces, the peak width of polishing layer 2 and the valley width of nonwoven fabric layer 3 are 30
It is sufficient if it is within the range of ~80 μm. Further, the angle that the polishing layer 2 and the nonwoven fabric layer 3 make with the longitudinal direction of the polishing tape is 20°~
It is sufficient if it is within a range of 70°.

Next, the inventors of the present application prepared an abrasive tape using the following materials and tested the initial good quality and reproducibility.

<Part 1> Fused alumina (average particle size 1 μm) 80 parts by weight Epoxy resin 14 parts by weight (solid content) Polyurethane resin 6 parts by weight (solid content) Lecithin
2.4 parts by weight Methyl ethyl ketone/toluene 90 parts by weight/90 parts by weight Above composition'
After mixing for 50 hours in a t=jf Lumir, 4 parts by weight (solid content) of an incyanate compound (Corone-IL, manufactured by Nippon I-Liurethane Co., Ltd.) was added, and the mixture was further kneaded for 1 hour to obtain a paint. This was coated on a polyester film with a thickness of 50 μm so that the thickness of the polishing layer 2 after drying was 15 μm.
0 μm) using a gravure roll, dried without smoothing, and cured at 65°C for 72 hours. The polishing layer 2 was then masked and a solution of polyurethane resin in 5-timethyl ethyl ketone was poured. After that, a sufficient amount of defibrated fiber components having a composition of 75% rayon and 25% polypropylene was sprayed into the recesses on the substrate, and then calendering was performed at 50°C and a linear pressure of 200ky/cm to slit the fibers into 1 inch width. and used as a sample.

Shit 2〉 30 lines/inch, 45° trapezoidal diagonal shape (crest width 80μ
A sample was obtained in the same manner as in Example 1, except that a gravure roll with a diameter of 80 μm and a valley width of 80 μm was used.

<Comparative example 1> After coating when forming the polishing layer 2 in Example 1.

A sample was obtained in the same manner as in Example 1, except that a smoothing treatment was immediately performed to remove irregularities on the surface of the coating film, and the nonwoven fabric layer 3 was not provided. Regarding each of these samples, the following items were investigated.

Regarding track quality, surface polishing of the flexible magnetic disk was performed using each sample prepared in the above Examples and Comparative Examples under conditions such that the gloss after polishing was 20% higher than that before polishing. Track quality was measured using a signal quality tester, and the percentage of non-defective products with a missing slice level of 80 or higher was calculated. Here, the signal level serving as a reference for error detection is the slice level when the average signal amplitude of the recording track is set to 100%.

Regarding reproducibility, reproducibility was determined based on the total number of samples that passed the initial inspection (100 samples).

The track quality of all the samples that passed the above track quality measurement was measured again five times in the same manner, and the non-defective rate was calculated.

Table 1 shows the track quality and reproducibility.

Table 1 Initial non-defective product rate) Reproducibility (ch)
Deluxe Example 1 95, 95100 99.
98 99 Example 2 92 99. 96
100 97 99・Comparative example 1 82
85 92 90 88 89 [Effects of the Invention] As described above, by using the abrasive tape according to the present invention, it is possible to obtain a magnetic recording medium with excellent track quality and further excellent reproducibility.

[Brief explanation of the drawing]

1 and 2 are a sectional view and a top view, respectively, of a surface polishing tape for magnetic recording media according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Support body, 2... Polishing layer, 3... Nonwoven fabric layer.

Claims (1)

[Claims] 1. An abrasive layer containing abrasive particles, a binder, and a dispersant as constituent components, and a nonwoven fabric layer consisting of a fiber component are provided on a support, and the abrasive layer and nonwoven fabric layer are alternately formed in the longitudinal direction. Surface polishing tape for magnetic recording media featuring