JP2885428B2 - Polishing film - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing film suitable for use in polishing and lapping, especially for finishing precision equipment and precision parts.

Conventional technology As this type of polishing film, conventionally, there is a film in which a coating material in which an abrasive is dispersed on a polyester resin such as PET is applied to form a continuous or discontinuous abrasive layer. And those using α-iron oxide fine powder.

Problems to be Solved by the Invention α-iron oxide fine powder used as an abrasive in the conventional polishing film as described above is granular, but their particle shapes are not always constant, and the particle size distribution is in a wide range. It spanned. Meanwhile, the uniformity of the particle shape and particle size of the abrasive in the polishing film greatly affects the state of the final finished surface of the object to be polished, and also affects the durability of the polishing film. That is, if the particle shape and particle size of the abrasive are not uniform, it is difficult to precisely control the finished surface roughness, and the durability of the abrasive film is reduced. Therefore, the particle shape and particle size of the granular iron oxide contained as an abrasive in the conventional polishing film,
As described above, since it is not always uniform, it is difficult to precisely control the finished surface with a conventional polishing film using granular iron oxide, and it cannot be said that the durability is also sufficient.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing film that can solve the conventional problems as described above.

Means for Solving the Problems A polishing film according to the present invention is characterized in that a polishing layer formed by dispersing cubic α-iron oxide abrasive grains in a binder resin is formed on a film substrate.

Next, the present invention will be described in more detail with reference to the accompanying drawings.

First, the present inventors use a polishing film to control the amount of polishing and the precision of the finished surface precisely, and also to increase the durability. I examined it. As a result, they have found that it is better to use abrasive grains having the following conditions.

(1) The particle shape is uniform and uniform.

(2) The particle size distribution is close to monodispersion.

The inventors have found that it is preferable to use cubic α-iron oxide abrasive grains as the abrasive grains having such conditions, and have reached the present invention.

FIG. 1 is a partially enlarged cross-sectional schematic view of a polishing film as one embodiment of the present invention. As shown in FIG. 1, the polishing film of this embodiment is obtained by dispersing cubic α-iron oxide (αFe ₂ O ₃ ) abrasive grains 2 in a binder resin 3A on a plastic film 1. The polishing layer is formed continuously.

FIG. 2 is a partially enlarged cross-sectional schematic view of a polishing film as another embodiment of the present invention. As shown in FIG. 2, the polishing film of this embodiment is the same as the polishing film of FIG. 1 except that the polishing layer is discontinuous or island-shaped. That is, the polishing layer provided discontinuously or in an island shape on the plastic film 1
Cubic α-iron oxide abrasive grains 2 are dispersed in 3B.

FIG. 3 is a partially enlarged cross-sectional schematic view of a polishing film as still another embodiment of the present invention. As shown in FIG. 3, the polishing film of this embodiment is the same as the polishing film of FIG. 1 except that the abrasive grains 2 are applied on the plastic film 1 in a single layer. That is, the polishing layer provided on the plastic film 1 includes the cubic α-iron oxide abrasive grains 2 applied in a single layer with the binder resin 3C.

The polishing films of these examples can be processed into any shape such as a tape, a sheet, and a disk and used.

In the polishing film of the present invention, as those suitable for use as cubic α-iron oxide abrasive grains, for example,
Bayer α-iron oxide ER, particle size 1μm ~ 0.1μ
m.

As the binder resin, thermoplastic and thermosetting resins can be used. The thermoplastic resin includes vinyl chloride resin, polyester resin, Alkit polyolefin resin, pure acrylic resin, nitrocellulose resin, nitrocellulose-acryl resin, deformed acrylic resin, and urethane elastomer which is a rubber resin. Nitrile rubber, silicone rubber, ethylene-vinyl acetate rubber, fluorine rubber, other water-soluble resins, and emulsion resins are used. As the thermosetting resin, polyester or acrylic polyol urethane-based resin, chlorinated polypropylene-modified acrylic polyol urethane-based resin, acrylic-
Chelate curable resin, epoxy or epoxy pendant acrylic resin and amine pendant acrylic resin, polyorganosiloxane resin, various UV curable resins, urethane oil resin, moisture curable polyurethane resin, fluorine resin, etc. Those in which the curing reaction proceeds are suitable.

As the plastic film serving as the base, polyethylene terephthalate, polyimide, polycarbonate, and their surface-treated films, polypropylene foamed butyl rubber, foamed neoprene, foamed soft polyethylene foamed synthetic rubber, other synthetic papers, nonwoven fabrics, and other metal foils are used.

 Next, specific experimental examples of the present invention will be described.

Specific Experimental Example This experimental example is a case where a thermosetting resin was used as a binder resin of a polishing layer in order to perform a test experiment on a polishing film according to the present invention. First, a coating composition having the composition shown in the following table is prepared.

Table 1 Cubic α-iron oxide abrasive grains 100 parts Binder resin (VAGH) 15 parts Hardener (Coronate HL) 15 parts Solvent (MEK / toluene) 70 parts 200 parts However, the numerical values indicate parts by weight and are cubic. The particle size of the α-iron oxide abrasive is d ₅₀ = 0.3 μm.

A coating agent having the composition shown in Table 1 was applied to a polyethylene terephthalate film having a thickness of 25 μm to a thickness of 5 to 12 μm using a gravure coater, a reverse roll coater, a knife coater, or the like. Time cured to give a polished film according to the invention. FIG. 4 shows an enlarged view of the surface of the polishing layer of the polishing film with a microscope. As is apparent from FIG. 4, the abrasive grains 2 dispersed in the binder resin 3 in the polishing layer are relatively uniform in shape and grain size. Thus, as is clear from the electron micrograph, the cubic iron oxide has a narrow particle size distribution, and by measuring the three-dimensional surface roughness of the polishing film, the surface roughness of the obtained polishing film is as follows: It was found to be very uniform.

Comparative Example As a comparative example with respect to the above-described embodiment according to the present invention, the above-described embodiment was performed except that granular α-iron oxide abrasive grains (average particle diameter d ₅₀ = 0.3 μm) were used instead of cubic α-iron oxide abrasive grains. A coating liquid having the same composition as in the example was prepared, and a polishing layer was formed on a similar substrate by a similar method to obtain a polishing film for comparison. FIG. 5 shows an enlarged view of the surface of the polishing layer of the polishing film with a microscope. As is clear from FIG. 5, the abrasive grains 2 'dispersed in the binder resin 3' in the polishing layer are not uniform in shape and grain size. Thus, ordinary granular iron oxide has a wide particle size distribution, as is clear from electron micrographs, and the three-dimensional surface roughness measurement of the polishing film shows that the obtained polishing film has a low surface roughness. The uniformity was confirmed.

The magnetic head was polished for 10 seconds using each of the polishing tapes of the above Examples and Comparative Examples, and the polished surface of the head was observed at 500 times with an optical microscope. As a result, in the one polished by the polishing tape of the comparative example,
It was found that a large number of scratches were formed on the head surface, and no such scratches were observed in the case where the head was polished with the polishing tape of the example according to the present invention. In addition, it was also confirmed that the polishing tape of the example according to the present invention can endure a longer polishing operation than the polishing tape of the comparative example.

Next, in the case of using a thermosetting resin as the binder resin according to the present invention, and in the case of using a thermoplastic resin, the change in the abrasive grain concentration of the cubic α-iron oxide abrasive grains dispersed therein. The results of experiments on how various characteristics such as durability of the formed polishing film change will be described.

First, VAGH which is a thermosetting resin as a binder resin
, The concentration of cubic α-iron oxide α-Fe ₂ O ₃ is adjusted to 1
Nine types of polishing films with 0, 20, 30, 40, 50, 60, 70, 80, and 90% by volume were prototyped, and the results of examining the breaking stress, breaking elongation, and durability of each polishing film were determined. , And Table 2. Based on the numerical values shown in Table 2,
FIG. 6 is a graph showing a change in rupture stress depending on the abrasive grain concentration and a change in rupture elongation depending on the abrasive grain concentration. In FIG. 6, a curve A shows a change in rupture stress depending on the abrasive grain concentration, and a curve B shows a change in rupture elongation depending on the abrasive grain concentration. As is clear from these graphs in Table 2 and FIG. 6, in the thermosetting film, the rupture stress increases with an increase in the iron oxide concentration, reaches a maximum value near 50% by volume, and decreases again. On the other hand, the elongation at break decreases within a range of several% due to an increase in the iron oxide concentration. Further, in the column of “Durability” in Table 2, ○, お よ び, and × indicate that these thermosetting films having different abrasive particle concentrations were applied under a pressure of 140 g / cm ² ,
It represents the result of examining the durability of the coating film by polishing the ferrite for 5 minutes at a rotation speed of 200 rpm and a work rotation speed of 125 rpm.
The mark indicates that the durability was very good, the mark ○ indicates that the durability was good, and the mark X indicates that the durability was poor. As is clear from this column of Table 2, the durability of the thermosetting film is determined by the concentration of abrasive grains.
A range of 20% to 70% by volume was good, with 40% to 60% being the best.

Next, N-23 which is a thermoplastic resin as a binder resin
04 using the concentration of cubic alpha iron oxide α-Fe ₂ O _3, 1
Nine types of polishing films with 0, 20, 30, 40, 50, 60, 70, 80, and 90% by volume were prototyped, and the results of examining the breaking stress, breaking elongation, and durability of each polishing film were determined. , And Table 3. Based on the numerical values shown in Table 3,
FIG. 7 is a graph showing a change in rupture stress depending on the abrasive grain concentration and a change in rupture elongation depending on the abrasive grain concentration. In FIG. 7, a curve A shows a change in rupture stress depending on the abrasive grain concentration, and a curve B shows a change in rupture elongation depending on the abrasive grain concentration. As is clear from the graphs in Table 2 and FIG. 6, in the case of the thermoplastic film, the breaking stress shows the maximum value at around 50% by volume, as in the case of the thermosetting film. Although the breaking stress is lower than that of the thermosetting film, the breaking elongation shows a value nearly 100 times larger. In addition, 、, お よ び, and × in the column of “Durability” in Table 3 represent the results of examining the durability of the coating film under the same polishing conditions as the thermosetting film described above. , ◎ mark indicates that the durability was very good,
A mark indicates that the durability was good, and a mark indicates that the durability was poor. As is clear from this column of Table 3, the durability of the thermoplastic film may be in the range of 20% by volume to 80% by volume, and 50% by volume.
The best results were found at 60% by volume.

Effect of the Invention Since the polishing film according to the present invention uses cubic α-iron oxide abrasive grains having a uniform shape and a sharp particle size distribution, a conventional polishing film using the conventional granular α-iron oxide abrasive grains The following effects can be obtained as compared with.

That is, since the cubic α-iron oxide abrasive grains have a uniform particle shape and a substantially monodispersed particle size distribution, they are dispersed in the binder resin in the polishing layer on the base of the polishing film. In the case where the polishing film is exposed to the surface of the polishing layer to perform a polishing action, there is no uneven pressure difference between the polishing film and the specific polishing object. Thus, the finished surface roughness can be controlled very precisely without causing unevenness in the roughness. Therefore, the polishing film of the present invention,
Suitable for final finishing of magnetic heads or polishing metal rolls.

In addition, the polishing film of the present invention can obtain a desired surface roughness in a short time and has improved durability as compared with a polishing film using conventional granular α-iron oxide abrasive grains.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional schematic diagram of a polishing film as one embodiment of the present invention, FIG. 2 is a partially enlarged cross-sectional schematic diagram of a polishing film as another embodiment of the present invention, and FIG. FIG. 4 is a partially enlarged cross-sectional schematic view of a polishing film as still another embodiment of the present invention, FIG. 4 is a diagram in which the surface of the polishing layer of the polishing film according to the present invention is enlarged by a microscope, and FIG.
FIG. 6 is an enlarged view of the surface of a polishing layer of a conventional polishing film with a microscope, FIG. 6 is a graph based on numerical values shown in Table 2, and FIG. 7 is a graph based on numerical values shown in Table 3. FIG. 1 ... Plastic film, 2 ... Cubic α iron oxide abrasive grains, 3A, 3B, 3C ... Binder resin.

Continuation of the front page (56) References JP-A-64-2874 (JP, A) JP-A-1-109084 (JP, A) JP-A-63-57175 (JP, A) JP-A-49-78900 (JP) JP-A-54-79408 (JP, A) JP-A-1-252366 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B24D 11/00 B24D 3/28 B24D 3/00 320 B24D 3/00 330

Claims (3)

(57) [Claims] 1. A polishing film comprising: a polishing layer formed by dispersing cubic α-iron oxide abrasive grains in a binder resin on a film substrate. 2. The binder resin is thermosetting,
The polishing film according to claim 1, wherein the concentration of the cubic α-iron oxide abrasive grains in the polishing layer is in a range of 20% by volume to 70% by volume. 3. The binder resin is thermoplastic,
2. The polishing film according to claim 1, wherein a concentration of the cubic α-iron oxide abrasive in the polishing layer is in a range of 20% by volume to 80% by volume.