JP3152968B2 - Polishing tape and method and apparatus for manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing tape used for polishing a workpiece made of a hard and brittle material such as glass, a crystalline material, a magnetic material, or ceramics, and more particularly, to a tape recorder or a video recorder. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing tape suitable for use in ultra-precision finishing such as curved surface polishing of a magnetic head such as a recorder, or mirror finishing of the surface of a magnetic disk or the end face of an optical fiber connector, and a method and an apparatus for manufacturing the same. .

[0002]

2. Description of the Related Art When finishing a workpiece made of a hard and brittle material, polishing using abrasive grains is generally performed. Recently, precision finishing of electronic parts and precision equipment parts has been demanded, and polishing tapes have been used for finishing. A polishing tape is a thin base film made of a material with a small expansion and contraction rate, such as polyester, on which fine abrasive grains are uniformly attached on one side. By pressing against the surface of a workpiece, the working surface is polished. In some cases, it is cut to an appropriate length and then attached to a lap base and polished.

According to such a polishing tape, the following effects can be obtained. Since the abrasive grains are uniformly applied, partial polishing unevenness and uneven scratches hardly occur, and an excellent finished surface can be obtained. Since processing is performed on a new portion of the tape, constant processing accuracy can always be obtained. Since it is a flexible tool, it is possible to reduce the processing stress and the generation of a deteriorated layer. In addition, since continuous automatic feeding can be performed by forming a roll, automation of the polishing process is easy.

Conventional polishing tapes have a grain size of 0.3 to
The particles had a particle size of about 30 μm and were firmly adhered to the substrate film by being mixed with an adhesive and coated.

[0005]

By the way, recently,
Surface roughness on the order of nanometers (Rmax = 0.1 to 10n)
Ultra-precision polishing to finish to m) is required. For such ultra-precision polishing, the particle size is 10
It is necessary to use ultra-fine abrasive grains of about 20 nm. However, if the particle size is 1 μm or less, the particles tend to aggregate. And when such agglomerated particles are present, since the size of the agglomerated particles becomes the effective particle size with respect to the finished surface roughness, no matter how small the particle size of the abrasive grains, scratches such as scratches occur on the finished surface Will be. In the conventional method of mixing abrasive grains into the adhesive, using ultra-fine abrasive grains as described above, the grains aggregate, so it is almost impossible to uniformly disperse them on the tape. Become.

In order to perform ultra-precision polishing, it is necessary to reduce the bonding force of the abrasive grains to some extent. If the bonding force of the abrasive grains is small, the abrasive grains easily fall off when they come into contact with the surface of the work piece. In addition to dripping, clogging due to polishing debris is prevented. However, if the bonding strength is too small, the abrasive grains will fall off during storage and transport of the polishing tape,
Abrasive grains on the tape become non-uniform, and a good finished surface cannot be obtained when polishing is actually performed using the abrasive grains. Therefore, it is desired that the bonding force of the abrasive grains be adjustable. It is difficult to control the adhesive force of a conventional method of bonding abrasive grains with an adhesive, so that it is almost impossible to adjust the bonding force of the abrasive grains.

[0007] Due to such problems, it has been impossible with a conventional polishing tape to finish the surface to the order of nanometers.

The present invention has been made in view of such circumstances, and has as its object to use ultra-fine abrasive grains capable of finishing a workpiece to a surface roughness of the order of nanometers. Is to get the polishing tape that was used. Also,
Another object of the present invention is to uniformly adhere ultra-fine abrasive grains to a base film with an appropriate bonding force,
An object of the present invention is to provide a manufacturing method and an apparatus for manufacturing a polishing tape as described above.

[0009]

In order to achieve this object, the present invention uses an electrophoresis method for attaching ultrafine abrasive grains. That is, the polishing tape according to the present invention has an electrically conductive thin film layer provided on one surface of an insulating substrate film, and the surface of the electrically conductive thin film layer is formed by attaching ultrafine abrasive particles by electrophoresis to form abrasive grains. It is characterized in that a layer is provided. The conductive thin film layer is desirably formed of a conductive polymer material having an adhesive property, but may be formed of a conductive polymer material or a metal having no adhesive property. When the conductive thin film layer does not have adhesiveness, it is desirable to attach a binder to the surface of the ultrafine abrasive grains. Further, the method for producing a polishing tape according to the present invention is a method of continuously passing a base tape having a conductive thin film layer provided on one surface of an insulating substrate film in a suspension in which ultrafine abrasive grains are dispersed. By applying a voltage between the conductive thin film layer of the tape and the suspension, the surface of the tape that passes through the suspension on the conductive thin film layer side, The present invention is characterized in that fine abrasive grains are attached, and the tape to which the abrasive grains are attached is dried. And the manufacturing apparatus of the polishing tape according to the present invention,
A drive roller that continuously moves in one direction a base tape provided with a conductive thin film layer on one side of an insulating base film, and a dispersion roller that is provided in a movement path of the tape and disperses ultrafine abrasive grains. A liquid tank containing the suspension, disposed in the liquid tank, and allowing the tape to pass through the suspension in the liquid tank by contacting the tape from the surface on the insulating substrate film side. And a conductive roller made of a conductive material that is provided on the tape inlet side of the liquid tank and that comes into contact with the surface of the tape on which the conductive thin film layer is provided.
A DC power supply that applies a voltage between the conductive roller and the suspension, and a dryer that dries the tape that has come out of the liquid tank,
It is characterized by having.

[0010]

The fine particles have a charge in a liquid phase, that is, a suspension state. Therefore, an electric repulsion acts between the particles. Therefore, the particles are stably dispersed. However, when an electric field is applied to such a suspension, the particles collect on the electrode side due to an electrophoretic phenomenon. When the suction force exceeds the electric repulsion between the particles, the particles adhere to the electrode. In that case, since the particles are uniformly dispersed in the suspension, the particles attached to the electrode are also uniform. Therefore, if the abrasive grains are adhered to the tape by the electrophoresis method as described above, even if the abrasive grains are ultrafine, they will adhere uniformly to the tape. In addition, since the abrasive grains adhere to the tape by an electric coupling force, the degree of coupling can be adjusted by changing the applied voltage.

[0011] In order to attach abrasive grains to the surface of the tape by the electrophoresis method, the tape must be used as one electrode. Therefore, a conductive thin film layer is provided on one side of the insulating base film constituting the base tape. The abrasive grains adhere to the surface of the conductive thin film layer to form an abrasive layer. In this case, if the conductive thin film layer is formed of an adhesive polymer material, the abrasive grains adhered with an appropriate bonding force will be held in that state. In the case of a conductive thin film layer having no adhesiveness, the bonding force can be maintained by attaching a binder to the surface of the abrasive grains. Thus, the polishing tape according to the present invention has ultra-fine abrasive grains uniformly attached thereto with a relatively small bonding force. Therefore, it is possible to perform ultra-precision finishing by polishing the workpiece using the tape.

Further, as in the method of manufacturing a polishing tape according to the present invention, a base tape having an electrically conductive thin film layer provided on one surface of an insulating base film is placed in a suspension in which ultrafine abrasive grains are dispersed. When a positive or negative potential is applied to the conductive thin film layer, ultrafine abrasive grains are uniformly attached to the tape surface on which the conductive thin film layer is provided. Then, when the tape is dried, the polishing tape as described above is formed.

Further, by configuring the polishing tape manufacturing apparatus as described above, a voltage is applied to the conductive thin film layer of the tape from the conductive roller. Further, since the guide roller comes into contact with the surface of the tape on which the abrasive grains of the tape are not adhered, the adhered abrasive grains prevent the roller from being worn. In that case, if a plurality of guide rollers are provided and the distance between the rollers is adjusted, the time for the tape to pass through the suspension changes, so the thickness of the abrasive grains can be controlled. Becomes

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a main part showing one embodiment of a polishing tape according to the present invention. As is clear from this figure,
The polishing tape 1 has a base film 2. The base film 2 is made of a flexible material having an insulating property and a small expansion and contraction rate, such as polyester, and one surface thereof is coated with a conductive polymer material having an adhesive property, whereby the conductive thin film layer 3 is formed. Is formed. An abrasive layer 4 is provided on the surface of the conductive thin film layer 3.
The abrasive grain layer 4 is formed by attaching silica particles 5, 5,... Which are ultrafine abrasive grains having a particle size of about 10 to 20 nm by electrophoresis, and a part of the silica particles 5 is electrically conductive. It penetrates into the inside of the conductive thin film layer 3, thereby keeping them bonded.

FIG. 2 shows another embodiment of the polishing tape according to the present invention. In this embodiment, portions corresponding to those in the embodiment of FIG. 1 are denoted by the same reference numerals. In the case of the polishing tape 1 of this embodiment, the conductive thin film layer 3 provided on one side of the insulating base film 2 is a metal foil. The metal foil is laminated on the base film 2 with an appropriate adhesive or the like. Then, silica particles 5, 5, 5, 5
Are provided. This abrasive layer 4
Also, the silica particles 5 are electrophoresed into the conductive thin film layer 3.
In this case, the binder 6 is adhered to the surface of the silica particles 5, and the silica particles 5 and 5 and the silica particles 5 are interposed via the binder 6. Particles 5 and conductive thin film layer 3 are maintained in a bonded state.

When a workpiece is polished by the polishing tape 1 configured as described above, the tape 1 is fed while the surface on the abrasive grain layer 4 side is pressed against the workpiece. Then, the surface of the workpiece is shaved by the silica particles 5 constituting the abrasive layer 4. In that case, since the silica particles 5 are very fine, the cut depth of the processed surface is very small. Moreover, since the abrasive layer 4 is formed by attaching the silica particles 5 by electrophoresis, the abrasive density is high. Therefore, the processed surface is precisely and uniformly polished. Further, silica particles 5 adhered by electrophoresis
Since the bonding force of the silica particles 5 is relatively small, the silica particles 5 that have come into contact with the workpiece and involved in polishing are easily shed. Therefore,
The polishing force is kept constant, and clogging due to polishing debris is also prevented. As a result, the processed surface is finished smoothly to a surface roughness of the order of nanometers.

FIG. 3 shows an embodiment of a polishing tape manufacturing apparatus according to the present invention used for manufacturing such a polishing tape 1. As shown in FIG. As is apparent from this figure, the polishing tape manufacturing apparatus 10 includes the base tape 1
1, a supply roller 12 for feeding out a tape in which the abrasive grain layer 4 is not formed in the polishing tape 1 of FIG. 1 or FIG. 2, and a polishing tape 1 manufactured by attaching abrasive grains to a base tape 11 thereof. Take-up roller 13 for winding
And The take-up roller 13 is driven to rotate by a motor (not shown), whereby the base tape 11 is continuously fed from the supply roller 12 side to the take-up roller 13 side. That is, in this embodiment, the winding roller 13 is a driving roller. The vicinity of the supply roller 12 and the winding roller 13
Are provided in the vicinity of, respectively, and a constant tension is applied to the tape 11 by the tension rollers 14 and 15.

A liquid tank 16 made of a conductive material such as a metal is provided in the moving path of the tape 11. The liquid tank 16 contains colloidal silica 17 in which silica particles 5, 5,..., Which are ultrafine abrasive particles having a particle size of about 10 to 20 nm, are dispersed in an alkaline liquid, that is, a suspension.
Further, a pair of guide rollers 18,
19 are provided. Those guide rollers 18, 19
Have a horizontal axis of rotation and are spaced apart from each other. In addition, one of the guide rollers 19 can be moved in the horizontal direction, and the interval therebetween can be adjusted. When the guide rollers 18 and 19 come into contact with the upper surface of the running tape 11, the tape 11 moves through the colloidal silica 17 from the right side to the left side in the figure.

A conductive roller 20 made of a conductive material is provided on a side wall on the inlet side of the liquid tank 16 from which the tape 11 is guided.
It is rotatably supported via an insulator 21. The roller 20 is configured to contact the lower surface of the tape 11. Then, a positive potential is applied to the conductive roller 20 by a DC power supply 22 provided between the conductive roller 20 and the liquid tank 16. DC power supply 22
It is assumed that the voltage can be adjusted.

Above the outlet of the liquid tank 16 from which the tape 11 exits, guide rollers 18 and 1 are attached to the tape 11.
A guide roller 23 that comes into contact from the same side as 9 is provided. Then, the tape 11 is
Is turned back in the horizontal direction so as to travel rightward in the figure. A drier 24 is provided below the tape 11 so that the tape 11 after coming out of the liquid tank 16 is dried.

As described above, the base tape 11 has the conductive thin film layer 3 provided on one surface of the insulating base film 2. The tape 11 is sent so that the surface on the side of the conductive thin film layer 3 becomes the lower surface in the liquid tank 16. That is, the conductive roller 20 is in contact with the conductive thin film layer 3, and the guide rollers 18, 19 and 23 are in contact with the insulating base film 2. Further, the tension roller 15 on the take-up roller 13 side is also in contact with the surface on the base film 2 side.

Next, the operation when the polishing tape manufacturing apparatus 10 thus configured manufactures the polishing tape 1 as shown in FIG. 1 will be described. When the polishing tape 1 of FIG. 1 is manufactured, a tape obtained by coating one surface of an insulating base film 2 with a conductive polymer material having adhesiveness is used as the base tape 11. First, the base tape 11 wound around the supply roller 12 is wound around the conductive thin film layer 3 so that the surface on the side of the conductive thin film layer 3 becomes the lower surface in the liquid tank 16 as shown in FIG. Drive. Then, the tape 11 moves from the right side to the left side in FIG. 3 through the colloidal silica 17 in the liquid tank 16.

In this state, the DC power supply 22 applies a positive potential to the conductive roller 20 and a negative potential to the liquid tank 16. The conductive roller 20 is in contact with the conductive thin film layer 3 of the tape 11. Therefore, by applying the voltage, a positive potential is applied to the conductive thin film layer 3, and the conductive thin film layer 3 becomes an anode with respect to the liquid tank 16. On the other hand, the silica particles 5 are negatively charged in the alkaline liquid. As a result, the colloidal silica 1 contained in the liquid tank 16
The silica particles 5 in 7 collect on the conductive thin film layer 3 side by electrophoresis, and adhere to the lower surface of the tape 11, that is, the surface on the conductive thin film layer 3 side by an electric coupling force.

In this way, while the tape 11 passes through the colloidal silica 17, the silica particles 5 which are ultrafine abrasive grains adhere to one surface of the tape 11, and the tape 11 is as shown in FIG. Polishing tape 1 having abrasive layer 4
Becomes In this case, since the conductive thin film layer 3 to which the silica particles 5 adhere is formed of a polymer material having an adhesive property, a part of the particles 5 penetrates into the conductive thin film layer 3 and exhibits an adhesive force. However, the degree of the penetration depends on the magnitude of the applied voltage. Therefore, the bonding force of the silica particles 5 is adjusted by controlling the voltage of the DC power supply 22. Further, since the silica particles 5 are uniformly dispersed in the colloidal silica 17, when a certain electric field is applied through the conductive thin film layer 3 of the tape 11, the tape 11
Adheres uniformly to Therefore, the resulting polishing tape 1
Means that ultra-fine abrasive grains are uniformly attached with an appropriate bonding force. Further, the abrasive grain density is also high. Further, during this time, the pair of guide rollers 1
By appropriately setting the interval between 8 and 19, the time for the tape 11 to pass through the colloidal silica 17 can be changed. Adjustment is also possible.

The polishing tape 1 thus formed
Is then dried by a dryer 24. Thereby, the polymer material forming the conductive thin film layer 3 is solidified,
The silica particles 5 are held in the bonded state. Then, the polishing tape 1 is taken up by a take-up roller 13 and stored or conveyed.

When the polishing tape 1 as shown in FIG. 2 is manufactured, a base tape 11 in which a metal foil is laminated on one surface of an insulating base material film 2 is used.
The colloidal silica 17 contains a polymer electrolyte binder 6 such as sodium alginate. Others are the same as in the above case. When the polymer binder 6 is added to the colloidal silica 17 as described above, the binder 6 adheres to the surface of the silica particles 5 to form a protective colloid. The colloid itself is negatively charged and collects at the anode in an electric field. Therefore, the polishing tape 1 as shown in FIG. 2 is obtained. In that case, the strength of aggregation of the silica particles 5 wrapped by the binder 6 differs depending on the magnitude of the applied voltage. Therefore, also in this case, by adjusting the voltage of the DC power supply 22, the bonding force of the silica particles 5 is adjusted.

As described above, when the polishing tape 1 shown in FIG. 2 is manufactured, the conductive thin film layer 3 in contact with the conductive roller 20 is formed.
Is assumed to have no adhesiveness, so that the conductive thin film layer 3 does not adhere to the conductive roller 20 and peel off. On the other hand, when the polishing tape 1 of FIG. 1 is manufactured, since the conductive thin film layer 3 may adhere to the conductive roller 20, the adhesive force cannot be increased so much. Therefore, it can be said that the polishing tape 1 of FIG. 2 is more preferable in adjusting the bonding force of the abrasive grains.
However, in any case, since the bonding force of the abrasive grains may be relatively small, there is almost no problem in producing the polishing tape 1 of FIG. Then, the polishing tape 1 as shown in FIG. 1 can be obtained at lower cost.

In such an apparatus 10 for manufacturing the polishing tape 1, the guide rollers 18, 19 and 23
To the surface on the side of the base film 2.
The same applies to the tension roller 15 on the winding roller 13 side. Since the surface is kept electrically insulative, the silica particles 5 as abrasive grains do not adhere to the surface. Therefore, these rollers 15, 18, 19, and
23 is prevented from being worn. Also, the conductive roller 2
Reference numeral 0 indicates that the conductive roller 20 contacts the conductive thin film layer 3 of the base tape 11 before the abrasive particles are attached thereto, and that the thin film layer 3 is energized. Is done.

The conductive thin film layer 3 may be made of a conductive polymer material having adhesiveness or a metal foil as in the above embodiment, or a normal conductive polymer having no adhesiveness. In that case, the polishing tape 1 may be configured as shown in FIG.

[0030]

As is clear from the above description, according to the present invention, since the abrasive grains are adhered to the tape by the electrophoresis method, even the extremely fine abrasive grains are uniformly dispersed. And the bonding force of the abrasive grains can be set appropriately. Therefore, a polishing tape that can be finished to a surface roughness of the order of nanometers can be obtained. Further, the production of the polishing tape can be performed continuously. Furthermore, the arrangement of the conductive roller and the guide roller can make the manufacturing process smooth.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing an embodiment of a polishing tape according to the present invention.

FIG. 2 is a longitudinal sectional view of a main part showing another embodiment of the polishing tape according to the present invention.

FIG. 3 is a schematic configuration diagram showing one embodiment of a polishing tape manufacturing apparatus of the present invention used for manufacturing the polishing tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polishing tape 2 Insulating base material film 3 Conductive thin film layer 4 Abrasive grain layer 5 Silica particles (ultrafine abrasive grains) 6 Binder 10 Polishing tape manufacturing apparatus 11 Base tape 12 Supply roller 13 Winding roller (drive roller) 16 Liquid tank 17 Colloidal silica (suspension) 18, 19 Guide roller 20 Conductive roller 22 DC power supply 24 Dryer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B24D 11/00

Claims (7)

(57) [Claims] An electrically conductive thin film layer is provided on one surface of an insulating base film, and an abrasive layer formed by attaching ultrafine abrasive particles to the surface of the electrically conductive thin film layer by electrophoresis. A polishing tape is provided. 2. The polishing tape according to claim 1, wherein the conductive thin film layer is formed of a conductive polymer material having an adhesive property. 3. The conductive thin film layer is made of a conductive polymer material or a metal having no adhesive property, and abrasive grains forming the abrasive grain layer are bonded via a binder. The polishing tape according to claim 1, wherein: 4. A method of continuously feeding a base tape having a conductive thin film layer provided on one surface of an insulating base film so as to pass through a suspension in which ultrafine abrasive grains are dispersed. By applying a voltage between the thin film layer and the suspension,
Attaching ultrafine abrasive grains in the suspension to the surface of the conductive thin film layer of the base tape passing through the suspension, and drying the obtained abrasive grain adhesion tape, Production method. 5. The method for producing a polishing tape according to claim 4, wherein a binder is contained in the suspension. 6. A drive roller for continuously moving a base tape having a conductive thin film layer provided on one side of an insulating base material film in one direction, and an ultrafine A liquid tank containing a suspension in which abrasive grains are dispersed; and a liquid tank disposed in the liquid tank, wherein the tape is brought into contact with the tape from the surface on the side of the insulating base material film so that the tape is placed in the liquid tank. A guide roller that guides the liquid to pass through the suspension, and a conductive material that is provided on an inlet side of the tape of the liquid tank and contacts a surface of the tape on which the conductive thin film layer is provided. Production of a polishing tape, comprising: a conductive roller comprising: a DC power supply for applying a voltage between the conductive roller and the suspension; and a dryer for drying the tape coming out of the liquid tank. apparatus. 7. The polishing tape manufacturing according to claim 6, wherein at least one pair of the guide rollers is provided in a horizontal direction and the interval between the guide rollers is adjustable. apparatus.