JPH04261777A - Polishing tool - Google Patents

Abstract

PURPOSE:To heighten grinding efficiency and obtain desirable cutting quality by using spherical glass beads as polishing material. CONSTITUTION:On a base 3 formed of a plastic film, unwoven cloth, foil, a glass plate, or the like, desirably a polyethylene terephthalate film (PE) of about 25-50mum, spherical glass beads 1 are disposed in such a way as to be substantially a single layer using binder resin 2 as adhesive. This results in considerably reducing the probability of scratches or flaws, different in quality (deeper and/or larger) from normal polished streaks, generated by a single grain to the polished surface roughness of polished material determined by the average grain diameter of polishing material grain, so that highly accurate polishing is attained.

Description

[Detailed description of the invention]

0001

[Technical field] The present invention can be used in the field of finishing processing such as texturing of precision instruments and precision parts, such as texturing of hard disks (magnetic recording media), polishing of metals such as silicon, polishing and lapping of glass, ceramics, plastics, etc. Regarding ingredients. The polishing tool of the present invention is particularly effective for texturing hard disks.

0002

2. Description of the Related Art Conventionally, polishing tools have been used in which a hard abrasive material such as fused alumina, silicon carbide, or diamond is formed on a PET film with a continuous or discontinuous polishing layer using a binder resin. Particularly in hard disk texturing, a polished surface with uniform width and depth is required. In the case of a polishing method in which the surface structure of the polishing tape is directly transferred as a polishing surface, such as texturing of a hard disk, the uniformity of the polishing surface of the polishing film is most important. Furthermore, as the recording density of hard disks increases, the surface roughness must also be kept small. Furthermore, it is necessary to further suppress scratches on such a smooth surface.

[0003] In order to solve this problem, the inventor of the present invention previously disclosed in Japanese Patent Application No. 63-58392, Japanese Patent Application No. 1-231724, etc., that a conventional abrasive (electro-fused alumina pulverized powder) was used to coat a polyester film. We proposed a polishing film with a structure consisting of a single layer of abrasive grains.

0004

However, the polishing performance cannot be said to be sufficient due to the shape and particle size distribution of the abrasive grains. The purpose of the present invention is to process the surface to be polished, especially the textured surface of a hard disk, so that the surface roughness is within the range of 20 to 100 Å, and in addition, the texturing process can be carried out without causing damage such as deep scratches, discontinuous lines, or scratches. An object of the present invention is to provide a polishing tool that allows easy control of the width and depth of a polishing line.

[0005]

[Means for Solving the Problems] The present invention solves the above problems with a polishing tool characterized by using spherical glass beads as an abrasive and fixed to a flexible support with a binder resin. do.

The present invention is characterized in that spherical glass beads are used as the abrasive instead of hard abrasives such as fused alumina, silicon carbide, and diamond. Spherical glass beads have never been used as an abrasive material until now, and have a lower hardness than the general abrasive grains mentioned above, so they do not fall into the category of so-called abrasives, but perhaps because of their spherical shape, they are used as abrasives. The spherical shape produces uniform polishing lines. Furthermore, because of the spherical shape, the glass beads have high dispersibility in the pre-resin and work without agglomeration of the particles. Furthermore, since the glass beads are spherical, the glass beads and the material to be polished come into point contact, resulting in high extreme pressure and improved grinding efficiency. Furthermore, since the contact points between the spherical beads and the material to be polished are uniform, the chip pocket is large, making it easy to discharge polishing debris and preventing clogging. In addition, since there are fewer contact points between the spherical beads and the material to be polished, friction with the material to be polished is reduced, resulting in better cutting performance.

[0007] As the glass that can be used in the present invention, spherical glass having a Mohs hardness of about 7 can be used. Generally, optical hard glass is suitable. For example, spherical beads, which are currently widely used in retroreflectors used in traffic signs, have uniform particle sizes and are suitable. The particle diameter of the glass beads is determined depending on the use or purpose of the textile ring, but generally an average particle diameter of 1 to 200 μm, preferably 20 to 50 μm is suitable. For example, recently, the surface roughness of the textured surface of a magnetic disk must be controlled within the range of 20 to 100 ÅRa (the lower limit is the roughness required to avoid the head from sticking to the hard disk when the magnetic head starts running). Surface roughness)
So, choose the diameter accordingly. Surprisingly, the textured polishing streaks are about a few tenths of the diameter of the glass beads, and the reason for this cannot be clearly explained. Patent Application No. 1983-58392 or Patent Application No. 1-23172
As described in No. 4, the spherical glass beads are preferably arranged discretely in a monolayer or in contact with each other. This provides an excellent polishing effect. Alternatively, spherical glass beads may be arranged in multiple layers, and even if the particles are irregular, there is no substantial problem. The reason for this is presumed to be that since the beads exposed on the surface are spherical, the points of contact with the polishing material are spaced almost uniformly from each other.

FIGS. 1 and 2 are a cross-sectional view and a plan view, respectively, showing a part of a single-layer type polishing tool using glass beads having a sharp particle size distribution, that is, having uniform particle sizes, according to the present invention, and FIG.
and FIG. 4 are a cross-sectional view and a plan view of a single-layer type polishing tool using the glass beads with a wide particle size distribution of the present invention, respectively, and FIG. 5 is a multi-layer type polishing tool using the glass beads with a wide particle size distribution of the present invention. It is a sectional view of a tool.

In FIGS. 1 and 2, the polishing tool has a binder on a base 3 of a plastic film, nonwoven fabric, metal foil, metal plate, glass plate, etc., particularly preferably a polyethylene terephthalate film (PE) of about 25 to 50 μm. It has a structure in which spherical glass beads 1 are arranged substantially in a single layer using resin 2 as an adhesive. For example, first, a binder is applied to a base together with a solvent, and before the binder dries, glass beads are scattered over the entire surface of the binder and fixed. A single layer here means that there is substantially no overlapping of particles. As a result, scratches (deeper and/or wider scratches) or abrasions that are different from normal polishing streaks caused by single particles can be removed from the surface roughness of the polished surface of the workpiece, which is determined by the average particle diameter of the abrasive particles. The probability of occurrence is significantly reduced, and high-precision polishing can be achieved.

Alternatively, as shown in FIG. 6, by applying spherical glass beads dispersed in a binder,
Although the binder resin may cover the surface layer of the glass beads thinly, it is preferable to expose the binder resin as much as possible as shown in FIG. 1. Therefore, in this case, a relatively large amount of solvent is used to produce a spherical glass bead-dispersed resin coating so that almost no resin remains on the surface of the glass beads after coating and drying. Such a single-layer abrasive layer can be produced relatively easily without using special methods by adjusting the appropriate polymer binder, solvent, dispersant, their blending ratio, coating means, coating amount, etc. I found out that it can be achieved.

[0011] Figures 3 and 4 show examples of polishing tools using glass beads with varying particle sizes, and the manufacturing methods are as follows.
There is no difference from the example shown in Figure 2.

The example shown in FIG. 5 shows the case where the paint is applied thickly in the coating process, and in this case, spherical glass beads are dispersed in the binder, or powder scattering may be used in combination with this.

In any case, since the glass beads are spherical, the particles exposed on the top surface do not overlap each other, and the points of contact with the material to be polished are always discrete. The base can be processed into any shape such as a tape, sheet, or disk.

As the binder resin, thermosetting resins and thermoplastic resins can be used. Examples of the thermosetting resins include polyester or acrylic polyol urethane resins, chlorinated polypropylene modified acrylic polyol urethane resins,
Acrylic-chelate curable resin, epoxy or epoxy pendant acrylic resin + amine pendant acrylic resin, polyorganosiloxane resin, various UV curable resins, urethanized oil resin, moisture curable polyurethane resin, fluorine resin, etc. 100℃ It is suitable that the curing reaction proceeds in the following manner.

[0015] As the thermoplastic resin, pure acrylic resin,
Vinyl chloride resin, nitrocellulose resin, nitrocellulose-acrylic resin, modified acrylic resin, alkyd resin, polyolefin resin, polyester resin, urethane elastomer which is a rubber resin, nitrile rubber, silicone rubber, ethylene vinyl acetate rubber , fluororubber resin, other water-soluble resins, and emulsion resins are used. As the base film substrate, plastic films such as polyethylene terephthalate, polyimide, polycarbonate, surface-treated films thereof, synthetic paper, nonwoven fabric, metal foil, etc. are used.

In one example, spherical glass beads are mixed with a binder resin and a solvent, and then coated onto a substrate such as a film using an appropriate coating means to adjust the coating thickness to an appropriate coating thickness depending on the particle size distribution of the abrasive particles. In another example, a mixture of a binder resin and a solvent without spherical glass beads mixed therein is adjusted to an appropriate coating thickness by an appropriate coating means and applied to a substrate such as a film. As the coating means, for example, a Meyer bar coater, a gravure coater, a reverse roll coater, a knife coater, etc. can be used. The film thus obtained is fixed to the substrate by drying or curing.

[0017]

Advantages of the Invention Since the present invention employs the above configuration, the following effects are produced. (1) Although glass beads are spherical, since the glass beads and the material to be polished come into point contact, the extreme pressure is high and the grinding efficiency is improved.They act effectively as an abrasive. In addition, the friction with the material to be polished is reduced, resulting in better sharpness.(2) Glass beads are spherical, so they produce uniform polishing lines. In addition to the above-mentioned main effects, an additional effect is that because the particles are spherical, the glass beads have high dispersibility in the pre-resin and work without particles agglomerating. Furthermore, since the contact points between the spherical beads and the material to be polished are uniform, the chip pocket is large, making it easy to discharge polishing debris and preventing clogging. Examples of the present invention will be described below.

[0018]

[Description of Examples] Example 1 Polyethylene terephthalate (PET) with a thickness of 50 μm
After coating the film with a polyester resin binder at a coating thickness corresponding to the various particle sizes of the spherical glass beads, Table 2
Spherical glass beads with different average particle diameters as shown in the figure are excessively scattered on the undried binder layer, adhesively fixed on the PET using a processing roller so that the height of the glass beads is even, and after removing the excess particles, the predetermined size is Made of Ni- for hard disks (3.5 inches), slit widthwise and processed into a tape shape.
It was used for polishing (texturing) a P-plated aluminum substrate. The polishing conditions were as shown in Table 1. Further, the polishing results were as shown in Table 2.

[0019]

[Table 1]

[0020]

[Table 2] As shown in Table 2, the results were extremely satisfactory, with no abnormal number (noticeable gouges) or scratches (deep and long scratches) observed.

Example 2 A paint was prepared by mixing spherical glass beads with a binder resin and a solvent according to the composition shown in Table 3.
Coated on a μm PET base. The tape was slit to a predetermined width and processed into a tape shape, and used for polishing (texturing) a Ni--P plated aluminum substrate for a hard disk (3.5 inches). The polishing conditions were as shown in Table 1. Further, the polishing results were as shown in Table 4.

[0022]

[Table 3]

[0023]

[Table 4] As shown in Table 2, the results were extremely satisfactory, and no abnormal number (number of noticeable gouges) or scratches (deep and long scratches) were observed.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a part of a single-layer polishing tool using glass beads with a sharp particle size distribution according to the present invention.

FIG. 2 is a plan view showing part of a single-layer polishing tool using glass beads with a sharp particle size distribution according to the present invention.

FIG. 3 is a cross-sectional view and a plan view of a single-layer polishing tool using glass beads with a wide particle size distribution according to the present invention.

FIG. 4 is a plan view of a single-layer polishing tool using glass beads with a wide particle size distribution according to the present invention.

FIG. 5 is a cross-sectional view of a multilayer polishing tool using glass beads with a wide particle size distribution according to the present invention.

FIG. 6 is a cross-sectional view of a single-layer polishing tool using glass beads with a wide particle size distribution according to the present invention, and is a cross-sectional view illustrating an example in which a polishing layer is formed using a paint containing glass beads mixed with a binder. It is.

[Explanation of symbols]

1 Spherical glass beads 2 Binder resin 3 Base

Claims (3)

[Claims] 1. A polishing tool characterized in that it uses spherical glass beads as a polishing material and is fixed to a flexible support with a binder resin. 2. The polishing tool according to claim 1, wherein the polishing layer is formed by adhering the polishing material in a monolayer structure as particles that do not substantially overlap on the film base using a binder resin. . 3. Claim 1, wherein the abrasive material is present in a single layer or multiple layers on a flexible support, and the surface of the abrasive material that comes into contact with the material to be polished is not coated with a resin. Polishing tool described in .