JPH03178776A - Polishing tool - Google Patents

Abstract

PURPOSE:To facilitate the control of the face shape to be worked by sticking a polishing material particle onto a base with a single layer actually and yet in the state of being dispersed as uniformly as possible in a resin. CONSTITUTION:A desired polishing tool is obtained by forming the polishing layer made by sticking a polishing material particle by a binder resin 3 with about monolayer structure having only a convolutional particle less than one piece per 100 pieces on a base 1 and being brought into contact as closely as possible in the face direction at the polishing material density of more than 50% per unit area. In this case, the mean particle diameter D50 of the polishing material particle 2 is set to 1-6mum.

Description

DETAILED DESCRIPTION OF THE INVENTION Although it was pointed out in the above-mentioned Japanese Patent Application No. 63-58392 that it is important that the abrasive particles have a single-layer structure, this requirement is also the most important in the present invention. However, the same application considers that it is better for the abrasive particles to be as loose as possible. This is because it was thought that as the abrasive particles approach each other, the number of superimposed particles will correspondingly increase, increasing the number of abrasive scratches. However, through subsequent research, the present inventor found that if the method of applying a mixture of abrasive particles and a binder to a substrate is appropriate, there is a method that can maintain a single layer structure even when the abrasive particles come into contact with each other. This discovery led to the present invention.

3 and 4 are a plan view and a sectional view, respectively, showing a part of the uniform application type polishing tool of the present invention, and FIGS.
The figures are a plan view and a sectional view of a non-uniform application type polishing tool of the present invention. These polishing tools are preferably made of plastic film, nonwoven fabric, metal foil, metal plate, glass plate, etc.
5-50 μm polyethylene terephthalate film (
A paint having abrasive particles 2 dispersed in a binder resin 3 is applied onto a base 1 of PET) so that the abrasive layer is substantially a single layer and the abrasive particles are in contact with each other in the in-plane direction as much as possible. It has a structure in which abrasive particles are coated so that they are present at a high density. Here, a single layer means that there is substantially no overlapping of particles, and preferably the number of overlapping points of two or more particles is 1 or less per 100 particles,
More preferably, the number is limited to one per 1,000 or less. ”
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. What must be avoided in the present invention is that the abrasive particles overlap one above the other to form abnormal protrusions.

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. The uniform abrasive material distribution shown in FIGS. 3 and 4 or the non-uniform abrasive material distribution shown in FIGS. 5 and 6 can be realized by adjusting the above-mentioned factors.

In either case, it is important that the density of the abrasive particles be so high that they are in contact with each other, and it is not important whether the abrasive particles are uniformly distributed or non-uniformly distributed.

The base can be processed into any shape such as tape, sheet, or disk.

Examples of the abrasive include diamond, CBN, silicone carbide, single crystal alumina, pulverized powder of fused alumina, chromium oxide, iron oxide, and cerium oxide, with fused alumina and diamond being particularly preferred. Fused alumina is particularly preferred for texturing metal plates with aluminum or plated surfaces, but harder materials, such as diamond, are used recently for texturing magnetic recording media in which a magnetic recording layer is attached to a thin glass substrate. I found out that I needed to.

The particle size of the abrasive material is an average particle size (D, .) of 1 to 12 μm,
Preferably, the thickness is 1 to 6 μm.

The texturing depth of the hard disk is determined by the surface roughness Ra.
In order to have an average particle diameter in the range of 20 to 100λ, it is necessary to have an average particle diameter approximately within this range, although it depends on the flexibility of the base. If the base is flexible, the particle size of the abrasive may be large, but if the base lacks flexibility, an abrasive with a small particle size is required.

Thermosetting resins and thermoplastic resins can be used as binder resins. Examples of thermosetting resins include polyester or acrylic polyol urethane resins, chlorinated polypropylene modified acrylic polyol urethane resins, acrylic-chelate curing resins, epoxy or epoxy pendants. Acrylic (6) (fatty amine pendant acrylic resin, polyorganosiloxane resin, various UV-curable resins, urethanized oil-based resins, moisture-curable polyurethane resins, fluorine thread resins, etc. The curing reaction proceeds at 100"C or less. things are suitable.

Thermoplastic resins include pure acrylic resin, vinyl chloride resin, nitrocellulose resin, nitrocellulose-acrylic resin, modified acrylic resin, alkyd resin, polyolefin resin, polyester resin, and urethane elastomer which is a rubber resin. , nitrile rubber, silicone rubber, ethylene 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, and surface-treated films thereof, synthetic paper, nonwoven fabric, metal foil, etc. are used.

(Manufacturing method of abrasive tool) Abrasive particles are mixed with a binder resin and a solvent, and then applied to a substrate such as a film using an appropriate coating method to adjust the coating thickness to an appropriate coating thickness depending on the particle size distribution of the abrasive particles.

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.

Figures 3 and 4 show a single-layer polishing layer with a uniform abrasive particle distribution.

Figures 5 and 6 show a single-layer polishing layer with non-uniform abrasive particle distribution.

The monolayer structure of the polishing layer with uniform abrasive particles and non-uniform abrasive particle distribution was controlled by the ratio of the dispersant in the binder resin.

Next, examples of the present invention will be described.

This example is an example in which a thermoplastic resin was used as the binder resin of the polishing layer in order to test the polishing film according to the present invention. First, a coating liquid having the composition shown in Table 1 was used. Prepared.

As the abrasive particles, pulverized powder WA of fused alumina was used, and various meshes having different average particle diameters were used. The abrasive particles used were as follows.

WA2500 (D S0 = 6.0 am) WA3
000 (D,.=4.5 μm) WA4000 (
D so = 3.0 um) WA6000 (D S
. = 2.0 μm) Table 1 (Parts by weight of alumina-thermoplastic resin) The composition of Table 1 including this dispersant (the polyester resin is V2O0 manufactured by Toyobo Co., Ltd.)
25μm using a gravure roll coater.
The film was coated on a polyethylene terephthalate film having a thickness of 100 mL, and after the solvent was dried, it was slit to a predetermined width and processed into a tape shape, which was then used for texturing and polishing of a nickel-plated hard disk substrate. Tables 2 and 3 show the surface roughness measurements of uniformly distributed and nonuniformly distributed abrasive tapes, respectively. Which is the average of several samples. Uniform distribution type and non-uniform distribution type abrasive tapes have almost the same surface roughness if they have a single layer structure, and the average particle diameter (D, .) of the particles used and the surface roughness difference Rz are almost equal, and Rmax is the polishing Take a value smaller than the maximum particle size of the material. A uniform distribution type abrasive tape has a structure in which abrasive particles are uniformly distributed in a single layer on a base using a dispersant.

A non-uniform polishing tape has abrasive particles present in a single layer on a base, but has a structure in which relatively large particles are aggregated and minute particles fill the gaps between the aggregates.

Table 2 (uniform distribution type) Table 3 (nonuniform distribution type) In the table, Ra, Rz Rmax represent the surface roughness according to the JIS standard.

Next, microscopic photographs of the cut surfaces of the abrasive tapes were examined, and it was found that in all the abrasive tapes, the number of superimposed abrasive particles was less than one per 100 particles.

Using the abrasive particles used in Example 1, a hard disk was textured and polished using a multilayer high-density abrasive tape having a Benard cell structure manufactured by a conventional method. A comparison was made with the abrasive tape of the embodiment of the invention. Using this abrasive tape, a hard disk was textured with the abrasive tape of the example under conditions to obtain the abrasive surface shown in Table 4, and the results shown in Table 5.6 were obtained.

Table 4 (Polished surface by the conventional polishing film of Comparative Example 1) Table 5 (Polished surface by the uniform distribution polishing tape of Table 1) Table 6 (Polished surface by the non-uniform polishing film of Table 2) The number of abnormalities indicates the number of gouges of noticeable size, and the number of scratches indicates the number of streaks larger than normal polishing streaks.

As is clear from the above table, it can be seen that the polishing tape having the single-layer polishing layer of the present invention provides a surface to be polished consisting only of normal polishing streaks.

Next, in the polishing test shown in Table 4.5.6, changes in polishing time and surface roughness over time were investigated. Results are average values of several samples. The results are shown in the graph of FIG. As is clear from the figure, while the conventional product reaches a certain level of surface roughness in about 30 seconds of polishing time, the product of the present invention reaches the desired surface roughness in about two-thirds of that time.

Next, in order to examine to what extent superimposed particles are allowed, the amount of the abrasive paint of Example 1 applied per unit area was changed in stages. Sections were taken from those with minimal scratches and observed under a microscope, and it was found that on average less than 1 in 100 scratches could be used for texturing hard disks.

FIG. 8 shows the relationship between the number of scratches (relative value) and the number of superimposed particles per unit area. From the figure, it was confirmed that scratches disappear when the number of superimposed particles is less than 1 per 100 particles.

This example is an example in which a thermosetting resin is used as the binder resin of the abrasive layer and diamond is used as the abrasive material. First, a coating liquid having the composition shown in Table 7 is prepared. did.

Diamond powder is used as the abrasive particles, and the particle size is 4 to 6.
Two different types were used: micron m and 6-12 μm. In this example, the particle diameter is not the average diameter, but represents a powder with an extremely sharp particle size distribution, which means that there are substantially no particles outside this range.

Table 7 (Diamond - parts by weight of thermosetting resin) Composition shown in Table 1 (The thermosetting resin used was a polyurethane prepolymer (manufactured by Nippon Polyurethane Co., Ltd.). After thoroughly mixing the composition, 50% of polyisocyanate was added as a curing agent. 25μ of the coating liquid (mixed in parts by weight) with a gravure roll caulk.
The mixture was coated onto a polyethylene terephthalate film having a thickness of 500 m in thickness according to various particle sizes, and after drying the solvent, it was cured by heat, and then slit to a predetermined width to form a tape. The particles had a nearly uniformly distributed monolayer structure with many particles partially in contact with each other.

Next, when observing microscopic photographs of the cut surfaces of the abrasive tapes mentioned above, it was found that the superposition of abrasive particles was 1000 in all abrasive tapes.
It was less than one per piece.

Next, these polishing tapes were used for texturing polishing of a 3.5-inch glass disk substrate for a hard disk. As a processing condition, do you polish by applying a certain pressure to the polishing tape? (While flowing the polishing tape, feed the polishing tape at a speed of 150 mm.
A polishing test was conducted by changing the rotational speed of the disk space spindle, the polishing time, and the vibration frequency (the frequency when the polishing tape is vibrated between the inner and outer edges of the polishing surface of the disk). No scratches occurred in any of the samples. Table 8 shows the results of measuring the surface roughness. Measurements were made at the center of the disk (the circle between the inner and outer circumferential circles).

From the table above, all Ra values are 100 even after 60 seconds of polishing time.
Since it is less than Å, the polishing tool of the present invention can be used for suitable texturing. Also, from the table, the surface roughness Ra gradually increases with time, but it is 50μ for particle diameters of 4 to 6μ.
Below, the particle diameter of 6 to 12 microns is 80 microns or less, and can be used depending on the required texturing.

Example 4 Next, in the same manner as in Example 3, a thermosetting abrasive tape was manufactured by applying an abrasive material to a polyethylene telecrate base with a thickness of 25 μm and 50 μm, and these tapes were used for other polishing. We conducted an experiment.

The polishing tape was polished without vibration. No scratches occurred in either case. Also, the surface roughness measurement results are
．． 10.11 The graph in Figure 11 shows.

These figures each show the relationship between the polishing time and the surface deviation Ra of the polished surface for the center, inner circumference, and outer circumference of the disk. From these figures, it can be seen that when the base is thin, the particle size of the abrasive is 6 to 12 μm, and the stability of the surface roughness can be obtained for a relatively long time, but when the base is thick, the abrasive with a large particle size is not suitable. I understand that there is something. On the contrary, it can be seen that when the base is thin and the particle size of the abrasive is small, stability in surface roughness can be obtained. Textures and rings of less than RalOOA cannot be obtained with a combination of a base thickness of 50 .mu.m and an abrasive particle size of 6 to 12 .mu.m, but are obtained in other cases.

(Functions and Effects) As described above, according to the present invention, the following effects can be achieved: (1) The abrasive particles are adhered to the base in a substantially single layer and dispersed as uniformly as possible in the resin. Therefore, the abrasive tape has a surface roughness that corresponds to the particle size distribution and shape of the abrasive particles, making it easy to control the shape of the surface to be machined.

2) Since the abrasive particles have a single-layer structure, there are no parts that fall off as aggregates during polishing compared to conventional polishing tools, so there is no possibility of damage such as deep scratches or scratches or discontinuous lines. It is now possible to obtain uniform texturing lines without any problems.

3) When the surface of the conventional Benard cell structure is slit into a tape shape and used as a tape-like polishing tool, the coating film is crushed due to fluctuations in tape tension and winding reaction force, and the surface condition changes between the beginning and the end of winding. Although variations occur in the polished surface, the monolayer structure of the present invention does not cause such variations and the same polished surface can always be obtained.

Furthermore, since there is no change in the polishing surface due to tape tension, the length of the polishing tool can be increased, the time required to replace the polishing tool can be shortened, and work efficiency can be increased.

4) In conventional tape-shaped polishing tools with a Benard cell structure, abrasive aggregates tend to fall off from the tape edges, causing scratches, but in the polishing tool of the present invention, there are no aggregates, so there is no such problem.

5) Although the polishing layer of the polishing tool of the present invention has a single-layer structure, the particles are in a dense state where they are in contact with each other in the in-plane direction. It has higher polishing efficiency than a layered structure and can shorten polishing time.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an outline of a conventional polishing tool, FIG. 2 is a cross-sectional view thereof, FIG. 3 is a plan view of a polishing tool according to an embodiment of the present invention, FIG. 4 is a cross-sectional view thereof, and FIG. 6 is a plan view of a polishing tool according to another embodiment of the present invention, FIG. 6 is a cross-sectional view, FIG. 7 is a graph showing the relationship between polishing time and surface roughness of the present invention and a conventional polishing tool, and FIG. A graph showing the relationship between the number of scratches (relative value) and the number of superimposed particles per unit area, and FIG.
Figures 10 and 11 show the central part of the surface to be polished, respectively;
It is a graph showing the relationship between polishing time and surface width of the inner circumferential portion and the outer circumferential portion. Fig. 1 Fig. 3 Fig. 5 Fig. 7 9 hours (sec) o, (o, o l o, ooI Red deficiency ΔRa for daytime breeding of single-species varieties) 00 2.00 24.00 36.00 Tokido-Q (Mii! ") 48.00 000 Fig. 5 ΔRa 0.00 12.00 24.00 36.00 B41ノ] 191 (wood) 48.00 60.00 Ra 0O 12,00 24, 0036,00 Rinba (ney) 800 600°

Claims (5)

[Claims] (1) Abrasive particles are placed on the base using a binder resin.
An abrasive layer was formed in which the abrasive particles had only 1 or less superimposed particles per 00 particles and were bonded together in an almost monolayer structure in which the abrasive particles were in contact as closely as possible in the surface direction with a concentration of abrasive particles of 50% or more per unit area. A polishing tool characterized by: (2) The polishing tool according to item 1 above, which uses abrasive particles having an average particle diameter (D_5_0) of 1 to 6 μm. (3) The polishing tool according to item 1 or 2, wherein the abrasive particles are uniformly applied on the base. (4) The polishing tool according to item 1 or 2, wherein the abrasive particles are applied non-uniformly on the base. (5) The polishing tool according to any of the above items 1 to 4, wherein the abrasive is selected from diamond and fused alumina.