JPH06278039A - Abrasive film - Google Patents

Abstract

PURPOSE:To eliminate the possibility of blinding at the inner peripheral portion of a roll so as to avoid variation in machining performance by laminating an abrasive layer containing spherical grains of a specific average grain size on a base, thus forming an abrasive film. CONSTITUTION:An abrasive material having an average grain size of about 0.4 to 3mum, such as alumina, silicon carbide, diamond and zirconia, and spherical grains selected from ceramics, glass and polymer beads, are mixed with a binder resin such as a thermoplastic or thermosetting resin and the mixture is evenly dispersed in a solvent to prepare a liquid for application. The liquid for application is applied to a base such as a polyester film and dried to form an abrasive layer so as to obtain an abrasive film. The amount of spherical grains added is preferable 3 to 5wt% of the abrasive material and the thickness of the abrasive layer is preferable 10 to 20mum. The abrasive film obtained has its surface property uniformly controlled inside a roll so that variation in machinability can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing film used for polishing the surface of a magnetic head.

[0002]

2. Description of the Related Art Since a magnetic head is in contact with a recording medium at the time of recording and reproducing, the head shape and finish surface accuracy are involved in sliding characteristics and magnetic characteristics, and surface polishing processing greatly contributes to performance. In the conventional polishing film for magnetic head, in order to improve the polishing accuracy, in the finishing step, usually abrasive grains of 3 μm or less such as aluminum oxide and silicon carbide are used, and a binder resin as a binder is selected. The processing performance of the polishing film is controlled by the mixing ratio of.

[0003]

Since the polishing film for a magnetic head is usually used in the form of a roll, the pressure applied to the film at the outer peripheral portion and the inner peripheral portion differs due to the winding tension at the time of slitting. Abrasive material sinks into the binder resin on the inner circumference side (blinds), the surface roughness of the polishing film decreases, and the processing performance changes at the inner circumference of the roll, which is a major problem during manufacturing. Was there.

[0004]

According to the present invention, in order to prevent the processing performance from deteriorating in a conventional polishing layer, by adding spherical particles having a particle size equal to or smaller than that of the polishing material, the processing performance at the inner and outer circumferences of the roll can be improved. A polishing film is formed that does not change.

That is, the present invention is a polishing film for a magnetic head, wherein a polishing film is formed by forming a polishing layer on a polyester substrate, and spherical particles are added to the polishing layer.

As the polishing material, one having an average particle diameter of 0.4 to 3 μm is used in order to improve polishing accuracy. Abrasive materials are alumina, silicon carbide, diamond,
It can be selected from zirconia, iron oxide, chromium oxide powder and the like.
On the other hand, the spherical particles have a particle size equal to or smaller than the particle size of the abrasive. If it is too large, polishing failure will occur. If it is too small, the inner circumference of the roll will be crushed. If the addition amount of the spherical particles is within the range of 3 to 5 wt% with respect to the abrasive, the desired effect can be sufficiently obtained. If it is too small, there is no effect, and if it is too large, the amount of abrasive material decreases, resulting in poor polishing. Materials for spherical particles include ceramics, glass,
Select from polymer beads. These abrasives and spherical particles are mixed with a binder resin such as a thermoplastic resin or a thermosetting resin and applied to a polyester film. It is suitable that the polishing layer has a thickness of 10 to 20 μm.

[0007]

When the ratio of the powder in the binder resin in the polishing layer is increased by adding the spherical particles, sinking (blinding) of the abrasive into the binder resin at the inner peripheral portion of the roll is avoided and the inside of the roll is prevented. It was confirmed that uniform processing performance could be obtained.

[0008]

EXAMPLES Examples of the present invention will be described below. Example 1 Al ₂ O ₃ and SiC (Showa Denko KK) having an average particle size of 2 μm
Manufactured by Nippon Shokubai Co., Ltd., a thermoplastic resin and a solvent are uniformly dispersed in a sand mill to form a paint, so that the polishing layer has a thickness of 10 to 20 μm on the polyester substrate. The coating thickness was adjusted to obtain a polishing film having a polishing layer having a multi-layered uniform structure. Abrasive coating composition Abrasive material 100 parts by weight Binder resin 29 parts by weight Polymer beads 3 parts by weight Solvent 100 parts by weight

Example 2 Al ₂ O ₃ (average particle size 2 μm) was prepared in the same manner as in Example 1.
On the other hand, the coating material was adjusted so that the polymer beads were 1, 5, 10 wt% to obtain a polishing film having a multi-layered uniform structure with a coating thickness of 10 to 20 μm. Abrasive coating composition Abrasive material 100 parts by weight Binder resin 29 parts by weight Polymer beads 1,5,10 parts by weight Solvent 100 parts by weight

Example 3 By the same operation as in Example 2, Al ₂ O ₃ (average particle size 2 μm
m), polymer beads having an average particle diameter of 2.5 μm were added so as to have a weight ratio of 3 wt%, to obtain a polishing film having a multi-layered uniform structure having different added particle sizes.

Example 4 The polishing films obtained in Examples 1, 2 and 3 were used for 12.7 m.
Slit processing was performed to a width of m and a length of 200 m to produce a roll-shaped polishing film. Leave this polishing film at room temperature for 9
One left for 0 days and tabletop temperature and humidity tester (Junior-
JTH type ETAC ENGENERING. CO.
LTD. ) A temperature / humidity test was carried out at 50 ° C. and 90% for 5, 10 and 15 days (however, in Example 3, only 15 days), and the outer peripheral portion and the central portion (100
m) and the inner peripheral portion were sampled, and the surface state of the polishing layer was measured with a scanning electron microscope (S-570, manufactured by Hitachi Ltd.) to obtain the results shown in Table 1.

[0012]

[Table 1]

Example 5 In Examples 1, 2 and 3, rolls (1
A flexible disk head processing experiment was carried out with a polishing film having a width of 2.7 mm and a length of 200 m, and the surface shape of the object to be polished was evaluated.

[0014]

[Table 2]

Comparative Example Al ₂ O ₃ and SiC (Showa Denko KK) with an average particle size of 2 μm
The abrasives of No. 1) were dispersed and applied with the same composition in a system in which spherical particles were not added to prepare a sample tape having a width of 12.7 mm and a length of 200 m. This was subjected to the same temperature and humidity test as in Example 4, and the polishing layer surface was observed with a scanning electron microscope. The results shown in Table 3 were obtained.

[0016]

[Table 3]

[0017]

From the results of Table 1, Table 2 and Table 3 above, in the polishing film for processing a magnetic head obtained in the present invention, a small amount of spherical particles, preferably 3 to 5 relative to the abrasive is used.
By adding wt%, the inner circumference of the roll is crushed,
The surface property is uniformly controlled within the roll without causing clogging, and it has become possible to eliminate variations in processing performance.

Claims (7)

[Claims] 1. A polishing film having a polishing layer formed on a substrate, wherein spherical particles are added to the polishing layer. 2. The polishing film according to claim 1, wherein the abrasive has an average particle size of 0.4 to 3 μm and the spherical particle size is equal to or smaller than the particle size of the abrasive. 3. The polishing film according to claim 1, wherein the polishing material is alumina, silicon carbide, diamond, zirconia, iron oxide, chromium oxide powder or the like. 4. The polishing film according to claim 1, wherein the thickness of the polishing layer is in the range of 10 to 20 μm. 5. The polishing film according to claim 1, wherein the binder resin is a thermoplastic resin or a thermosetting resin. 6. The polishing film according to claim 1, wherein the spherical particles are made of ceramics, glass or polymer beads. 7. The amount of spherical particles added is 3 with respect to the abrasive.
The polishing film according to claim 1, which is in the range of ˜5 wt%.