CN109311141B

CN109311141B - Grinding material

Info

Publication number: CN109311141B
Application number: CN201780035886.5A
Authority: CN
Inventors: 西藤和夫; 下山贤治; 岩永友树; 笹岛启佑; 高木大辅; 八田朋树; 田浦歳和
Original assignee: Bando Chemical Industries Ltd
Current assignee: Bando Chemical Industries Ltd
Priority date: 2016-06-13
Filing date: 2017-04-18
Publication date: 2021-01-05
Anticipated expiration: 2037-04-18
Also published as: WO2017217108A1; JPWO2017217108A1; JP6340142B2; TW201742709A; CN109311141A; TWI719210B

Abstract

The polishing material of the present invention comprises a substrate sheet and a polishing layer laminated on the surface side of the substrate sheet and containing abrasive grains and a binder thereof, wherein the polishing layer is divided in a polishing direction and has a plurality of types of polishing regions having different amounts of wear in a Taber wear test, and the ratio of the amount of wear of a polishing region having a large amount of wear to the amount of wear of a polishing region having a small amount of wear in a pair of adjacent polishing regions is 1.1 or more and 7 or less. The two types of polishing regions may be alternately arranged along the polishing direction. Each of the polishing regions may have a size capable of containing a circle having a diameter of 5cm in a plan view.

Description

Grinding material

Technical Field

The present invention relates to a polishing material.

Background

In recent years, as substrates for precision electronic devices such as hard disks (hard disks), Light Emitting Diodes (LEDs), power devices (power devices), and the like, there has been an increasing demand for difficult-to-process substrates such as glass, sapphire, silicon carbide, and the like. For polishing of such a substrate difficult to process, planarization accuracy with less damage and a high polishing rate are required.

In order to meet the above requirement, there has been proposed an abrasive material having a polishing portion in which diamond abrasive grains and a filler are dispersed (see Japanese patent application laid-open No. 2002-542057). In the above-described conventional polishing material, as the surface of the object to be polished is polished, the filler is detached from the polishing portion, and the diamond abrasive grains protrude from the surface of the polishing portion. The previous abrasive maintains planarization accuracy by the protrusion of the diamond abrasive grains, and improves polishing rate.

However, when such a conventional polishing material is continuously polished, polishing dust gradually accumulates between the polishing portion and the object to be polished, and the abrasive grains of the polishing material and the object to be polished are hard to come into contact with each other, so that so-called clogging is likely to occur. Therefore, in the conventional polishing materials, the polishing rate tends to decrease with time, and the polishing efficiency tends to decrease.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2002-542057

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of such problems, and an object of the present invention is to provide a polishing material having a high polishing rate and less likely to cause a reduction in polishing efficiency.

Means for solving the problems

The present invention has been made to solve the above problems, and an object of the present invention is to provide a polishing material including a substrate sheet and a polishing layer laminated on a surface side of the substrate sheet and containing abrasive grains and a binder thereof, wherein the polishing layer is divided in a polishing direction and has a plurality of types of polishing regions having different amounts of abrasion in a tamber (Taber) abrasion test, and a ratio of the amount of abrasion of a polishing region having a large amount of abrasion to the amount of abrasion of a polishing region having a small amount of abrasion in a pair of adjacent polishing regions is 1.1 or more and 7 or less.

Since the polishing material has a plurality of types of polishing regions having different amounts of abrasion in the tamarix abrasion test, when the polishing material is used for polishing, the polishing region having a large amount of abrasion in a pair of adjacent polishing regions is abraded first. In the polishing material, since the ratio of the abrasion amount in the polishing region having a large abrasion amount to the abrasion amount in the polishing region having a small abrasion amount in the pair of adjacent polishing regions is not less than the lower limit, a moderate step difference is generated between the pair of adjacent polishing regions in a short time from the start of polishing, and the surface pressure (surface pressure) is increased in the polishing region having a small abrasion amount. Therefore, the polishing material can more effectively apply the surface pressure during polishing, so that the polishing rate is high. Further, in the polishing material, since the ratio of the abrasion amount is not more than the upper limit, the step is not excessively increased, and the polishing material is divided along the polishing direction, so that the polishing material can polish the object while crossing the step without damaging the object. When the object to be polished crosses the step, the gripping (grip) force of the polishing material is increased by the so-called crossing resistance of the object to be polished pressing the object to be polished to the step, and the surface pressure is increased in a region having a large height, so that the surface pressure at the time of polishing can be effectively applied, and therefore the polishing rate of the polishing material is not easily lowered.

The two types of polishing regions may be alternately arranged along the polishing direction. By alternately arranging two types of polishing regions in this manner, it is possible to suppress an increase in the production cost of the polishing material while maintaining the effect of improving the polishing rate and the effect of suppressing a decrease in the polishing efficiency.

Each of the polishing regions may have a size capable of containing a circle having a diameter of 5cm in a plan view. By thus making each polishing region a size that can include a circle having a diameter of 5cm in plan view, the grip strength improving effect by the cross resistance is more reliably obtained.

The binder may contain a filler containing an inorganic oxide as a main component, and the average particle diameter of the filler may be smaller than the average particle diameter of the abrasive grains. By providing the binder with a filler containing an oxide as a main component in this manner, the elastic coefficient of the binder can be increased, and the abrasion of the polishing layer can be easily controlled. Further, by making the average particle diameter of the filler smaller than the average particle diameter of the abrasive grains, the polishing force of the abrasive grains is less likely to be inhibited. Therefore, the effect of increasing the polishing rate can be maintained.

Here, the "polishing direction" refers to a direction in which the polishing material moves during polishing, and for example, a disk-shaped polishing material refers to a circumferential direction. In addition, "abrasion amount in the tamariskoid abrasion test" is a value obtained as follows: a test piece was prepared, and the test piece was rotated 320 revolutions using a Taber abrasion tester under conditions of an abrasion wheel H-18 and a load of 4.9N (500gf), and the difference in mass of the test piece before and after 320 revolutions was measured, and the area of the obtained value was converted into the difference in mass of a test piece having a diameter of 104 mm. The "polishing region" of the polishing layer means each region in the case where the polishing layer is divided in a range where the variation in the amount of abrasion in the tamariska abrasion test is within 3%.

The term "main component" refers to a component having the largest content, and for example, refers to a component having a content of 50% by mass or more. The "average particle diameter" refers to a 50% value (50% particle diameter, D50) of a volume-based cumulative particle size distribution curve measured by a laser diffraction method or the like.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, the polishing material of the present invention has a high polishing rate and is less likely to decrease in polishing efficiency. Therefore, the polishing material can be preferably used for polishing a substrate difficult to process such as glass, sapphire, and silicon carbide.

Drawings

Fig. 1A is a schematic plan view showing a polishing material according to an embodiment of the present invention.

FIG. 1B is a schematic cross-sectional view of the polishing material of FIG. 1A taken along line A-A.

FIG. 2 is a schematic cross-sectional view showing a polishing material according to an embodiment different from that shown in FIG. 1B.

Description of the symbols

1. 2: grinding the material;

10. 11: a substrate sheet;

20: a polishing layer;

21: grinding particles;

22: a binder;

23: a groove;

24: a grinding section;

30: a bonding layer;

40: a support;

41: a support adhesion layer;

x: a first grinding area;

y: a second grinding area;

A-A: cross hatching.

Detailed Description

[ first embodiment ]

Hereinafter, a first embodiment of the present invention will be described in detail with reference to the accompanying drawings as appropriate.

< abrasive Material >

The polishing material 1 shown in fig. 1A and 1B is disk-shaped and mainly includes a substrate sheet 10 and a polishing layer 20 laminated on the surface side of the substrate sheet 10. The polishing material 1 further includes an adhesive layer 30 laminated on the back surface side of the base sheet 10. The polishing material 1 is disposed on a polishing platen of a known polishing apparatus, and is rotated while being brought into contact with an object to be polished by the polishing apparatus, thereby performing polishing. That is, the polishing direction of the polishing material 1 is the circumferential direction of the base sheet 10.

(substrate sheet)

The substrate sheet 10 is a member for supporting the polishing layer 20. The material of the substrate sheet 10 is not particularly limited, and includes: polyethylene terephthalate (PET), Polypropylene (PP), Polyethylene (PE), Polyimide (PI), Polyethylene naphthalate (PEN), aramid (aramide), aluminum, copper, and the like. Among them, aluminum having good adhesion to the polishing layer 20 is preferable. The surface of the base sheet 10 may be subjected to a treatment for improving adhesion, such as a chemical treatment, a corona treatment, or a primer treatment.

In addition, the substrate sheet 10 may have flexibility or extensibility. By providing the substrate sheet 10 with flexibility or ductility in this way, the polishing material 1 follows the surface shape of the object to be polished, and the contact area between the polishing surface and the object to be polished increases, so that the polishing rate is further increased. Examples of the material of the flexible substrate sheet 10 include PET and PI. The material of the ductile base material sheet 10 may be aluminum, copper, or the like.

The size of the substrate sheet 10 is not particularly limited, and may be, for example, 200mm or more and 2022mm or less in outer diameter and 100mm or more and 658mm or less in inner diameter.

The average thickness of the substrate sheet 10 is not particularly limited, and may be, for example, 50 μm or more and 1mm or less. If the average thickness of the base sheet 10 is less than the lower limit, the strength or flatness of the abrasive material 1 may be insufficient. On the other hand, if the average thickness of the base sheet 10 exceeds the upper limit, the polishing material 1 becomes unnecessarily thick, which makes handling difficult.

(polishing layer)

The polishing layer 20 contains abrasive grains 21 and a binder 22 therefor. The polishing layer 20 includes a plurality of polishing portions 24 defined on a surface thereof by grooves 23.

The polishing layer 20 is divided along the polishing direction, that is, the circumferential direction of the base material sheet 10, and has two types of polishing regions having different amounts of abrasion in the tambour wear test. Specifically, the entire polishing layer 20 is divided into four polishing regions by two straight lines (broken lines in fig. 1A) passing through the center of the surface of the substrate sheet 10, and two regions are alternately arranged in the first polishing region X and the second polishing region Y along the polishing direction. In the first polishing region X and the second polishing region Y, a plurality of polishing portions 24 are disposed, which are defined by the grooves 23 and the outer edge of the base material sheet 10. In addition, the term "entire polishing layer" is a concept including the groove and the outer edge of the substrate sheet when the polishing layer has the groove, except for the polishing portion.

The average thickness of the polishing layer 20 (average thickness of the polishing portion 24) is not particularly limited, but is preferably 25 μm, more preferably 30 μm, and still more preferably 200 μm. On the other hand, the upper limit of the average thickness of the polishing layer 20 is preferably 4000 μm, more preferably 3000 μm, and still more preferably 2500 μm. When the average thickness of the polishing layer 20 is less than the lower limit, the polishing of the polishing layer 20 becomes faster, and thus the durability of the polishing material 1 is insufficient. On the other hand, when the average thickness of the polishing layer 20 exceeds the upper limit, the polishing material 1 may become unnecessarily thick, which may make handling difficult.

(abrasive grain)

Examples of the abrasive grains 21 include various abrasive grains such as diamond abrasive grains, alumina abrasive grains, and silica abrasive grains. Among them, diamond abrasive grains are preferable. By using diamond abrasive grains as the abrasive grains 21 in this manner, a higher polishing force than other types of abrasive grains can be obtained, so that the surface pressure during polishing can be more effectively applied, and the grip strength improving effect due to the cross resistance can be more reliably obtained.

Further, the diamond of the diamond abrasive grain may be single crystal or polycrystalline, or may be diamond treated with Ni coating or the like. Among these, single crystal diamond and polycrystalline diamond are preferable. Single crystal diamond is hard and has high abrasive force in diamond. Further, polycrystalline diamond is easily cleaved in units of crystallites constituting a polycrystal and is not easily passivated, so that a decrease in polishing rate is small.

The lower limit of the average particle diameter of the abrasive grains 21 is preferably 2 μm, and more preferably 10 μm. The upper limit of the average particle diameter of the abrasive grains 21 is preferably 50 μm, and more preferably 45 μm. If the average particle diameter of the abrasive grains 21 is smaller than the lower limit, there is a problem that the polishing rate becomes insufficient. On the other hand, if the average particle diameter of the abrasive grains 21 exceeds the upper limit, there is a problem that the object to be polished is damaged.

The lower limit of the content of the abrasive grains 21 in the polishing layer 20 is preferably 2 vol%, and more preferably 3 vol%. The upper limit of the content of the abrasive grains 21 is preferably 55 vol%, more preferably 45 vol%, and still more preferably 35 vol%. If the content of the abrasive grains 21 is less than the lower limit, there is a problem that the polishing rate is insufficient. On the other hand, if the content of the abrasive grains 21 exceeds the upper limit, there is a problem that the holding force of the abrasive grains 21 of the polishing layer 20 is insufficient.

Furthermore, the content of the abrasive particles 21 may be changed in the first polishing region X and the second polishing region Y. In this case, the content of the abrasive grains 21 in the second polishing region Y is preferably smaller than the content of the abrasive grains 21 in the first polishing region X, and the content of the abrasive grains 21 in the second polishing region Y may be 0 vol%. Since the surface pressure of the polishing material 1 is increased in the first polishing region X having a small amount of wear, the polishing efficiency of the first polishing region X is higher than that of the second polishing region Y. Therefore, the polishing efficiency is less likely to decrease when the content of the polishing particles 21 in the second polishing region Y is decreased than when the content of the polishing particles 21 in the first polishing region X is decreased. Therefore, by making the content of the abrasive grains 21 in the second polishing region Y smaller than the content of the abrasive grains 21 in the first polishing region X, it is possible to reduce the manufacturing cost of the polishing material 1 while suppressing a decrease in polishing efficiency to a small extent.

The type or average particle size of the abrasive grains 21 may be changed between the first polishing region X and the second polishing region Y, but it is preferable that the type or average particle size of the abrasive grains 21 is the same from the viewpoint of controllability of the wear ratio between the first polishing region X and the second polishing region Y.

(Binder)

The main component of the binder 22 is not particularly limited, and examples thereof include resins and inorganic substances.

Examples of the resin include: resins such as polyacrylic acid, polyurethane, epoxy resin (epoxy), cellulose, polyethylene, polyphenol, polyester, and phenoxy resin. Furthermore, the resin may also be at least partially crosslinked.

In addition, the inorganic substances include: silicates, phosphates, polyvalent metal alkoxides, and the like.

When the polishing object is a substrate made of a hard and brittle material such as sapphire or silicon carbide, the main component of the binder 22 is preferably an inorganic substance. Since the inorganic binder has higher hardness than the resin binder, the polishing force of the polishing material 1 is increased, and the hard and brittle material substrate can be easily processed. Among the inorganic substances, silicates having high retention of the abrasive grains 21 in the polishing layer 20 are preferable.

When the object to be polished is a brittle material substrate such as glass, the main component of the binder 22 is preferably a resin. The resin binder has a lower hardness than the inorganic binder, and can prevent the object to be polished from being damaged.

The main component of the binder 22 may be changed between the first polishing region X and the second polishing region Y, but from the viewpoint of controllability of the wear ratios of the first polishing region X and the second polishing region Y, it is preferable that the main component of the binder 22 is the same.

The binder 22 may contain a filler containing an oxide as a main component. By thus including the filler containing an oxide as a main component in the binder 22, the elastic coefficient of the binder 22 can be increased, and therefore, the abrasion of the polishing layer 20 can be easily controlled. Therefore, since an appropriate level difference is likely to occur in the adjacent region of the polishing material 1 during polishing, the polishing rate improving effect and the polishing efficiency reduction suppressing effect can be more reliably obtained.

Examples of the filler include: oxides such as alumina, silica, ceria, magnesia, zirconia, and titania, and composite oxides such as silica-alumina, silica-zirconia, and silica-magnesia. These fillers may be used alone or in combination of two or more if necessary. Among them, alumina is preferable because high polishing force can be obtained.

The average particle diameter of the filler also depends on the average particle diameter of the abrasive grains 21, but the lower limit of the average particle diameter of the filler is preferably 0.01 μm, more preferably 1 μm, and still more preferably 2 μm. On the other hand, the upper limit of the average particle diameter of the filler is preferably 20 μm, and more preferably 15 μm. If the average particle diameter of the filler is smaller than the lower limit, the effect of improving the elastic modulus of the binder 22 by the filler is insufficient, and there is a problem that the control of the abrasion of the polishing layer 20 is insufficient. On the other hand, if the average particle diameter of the filler exceeds the upper limit, there is a problem that the filler interferes with the polishing force of the abrasive grains 21.

The average particle diameter of the filler is preferably smaller than the average particle diameter of the abrasive grains 21. The lower limit of the ratio of the average particle size of the filler to the average particle size of the abrasive grains 21 is preferably 0.1, and more preferably 0.2. On the other hand, the upper limit of the ratio of the average particle size of the filler to the average particle size of the abrasive grains 21 is preferably 0.8, and more preferably 0.6. If the ratio of the average particle diameter of the filler to the average particle diameter of the abrasive grains 21 is less than the lower limit, the effect of improving the elastic coefficient of the binder 22 by the filler is insufficient, and there is a problem that the control of the abrasion of the polishing layer 20 is insufficient. On the other hand, if the ratio of the average particle diameter of the filler to the average particle diameter of the abrasive grains 21 exceeds the upper limit, the filler may interfere with the polishing force of the abrasive grains 21.

The content of the filler in the polishing layer 20 also depends on the content of the abrasive grains 21, but the lower limit of the content of the filler is preferably 15 vol%, and more preferably 30 vol%. On the other hand, the upper limit of the content of the filler is preferably 85% by volume, and more preferably 75% by volume. If the content of the filler is less than the lower limit, there is a problem that the effect of improving the elastic modulus of the binder 22 by the filler is insufficient, and the control of the abrasion of the polishing layer 20 becomes insufficient. On the other hand, if the content of the filler exceeds the upper limit, the filler may interfere with the polishing force of the abrasive grains 21.

Furthermore, the content of the filler may be changed in the first polishing region X and the second polishing region Y. In this case, the content of the filler in the second polishing region Y is preferably larger than the content of the filler in the first polishing region X. Generally, if the content of the filler is increased, the polishing layer 20 is easily worn. Therefore, by making the content of the filler in the second polishing region Y larger than the content of the filler in the first polishing region X, the wear ratio between the first polishing region X and the second polishing region Y can be more reliably controlled. The lower limit of the difference in the content of the filler between the first polishing region X and the second polishing region Y is preferably 3 vol%, and more preferably 5 vol%. On the other hand, the upper limit of the difference in the content is preferably 15% by volume, more preferably 12% by volume. If the difference in the content is less than the lower limit, the abrasion ratio between the first polishing region X and the second polishing region Y becomes too small, the step difference between the first polishing region X and the second polishing region Y becomes small, and the grip improvement effect by the cross resistance is insufficient. On the contrary, if the difference in the content exceeds the upper limit, the wear ratio between the first polishing region X and the second polishing region Y becomes excessively large, and the step difference between the first polishing region X and the second polishing region Y becomes large. This causes an excessive cross resistance, which causes a problem of edge chipping or cracking of the object to be polished.

In addition, the type of the filler may be changed between the first polishing region X and the second polishing region Y, but it is preferable that the type of the filler is the same from the viewpoint of controllability of the wear ratio between the first polishing region X and the second polishing region Y. In addition, the average particle diameter of the filler may be changed in the first polishing region X and the second polishing region Y. The larger the average particle size of the filler is, the more easily the abrasion of the polishing layer 20 increases, but the change in the amount of abrasion is smaller than in the case where the content of the filler in the polishing layer 20 is changed. Therefore, the control accuracy of the abrasion amount can be improved by controlling the abrasion amount by the content of the filler and changing the average particle diameter of the filler.

The binder 22 may contain various additives such as a dispersant, a coupling agent, a surfactant, a lubricant, an antifoaming agent, and a colorant, and additives, as appropriate according to the purpose. In addition, the resin of the binder 22 may also be at least partially crosslinked.

(tank)

The grooves 23 are formed in a lattice shape at equal intervals on the front surface side of the polishing layer 20. The bottom surface of the groove 23 is formed by the surface of the base sheet 10. The width of the groove 23 is substantially equal. That is, the plurality of polishing portions 24 have the same square shape in a plan view in one region and are arranged at substantially equal density.

In addition, a groove 23 may be provided on a boundary dividing the adjacent regions. By providing the grooves 23 at the boundary in this manner, the step difference generated between the regions by polishing faces across the grooves 23, so that the grooves 23 serve as buffer regions and the occurrence of edge chipping or cracking of the object to be polished can be suppressed.

The lower limit of the width of the groove 23 is preferably 03mm, more preferably 0.5 mm. The upper limit of the width of the groove 23 is preferably 15mm, and more preferably 10 mm. If the width of the groove 23 is less than the lower limit, the groove 23 may be clogged with the abrasive powder generated by the grinding. On the other hand, if the width of the groove 23 exceeds the upper limit, the object to be polished is likely to fall into the groove 23, and there is a problem that the object to be polished is damaged during polishing.

The lower limit of the area of each polishing portion 24 is preferably 0.5mm²More preferably 1mm². On the other hand, the upper limit of the area of the polishing portion 24 is preferably 13mm²More preferably 7mm². If the area of the polishing portion 24 is smaller than the lower limit, there is a problem that the polishing portion 24 is peeled off from the base sheet 10. On the other hand, if the area of the polishing portion 24 exceeds the upper limit, the number of polishing portions 24 that come into contact with the object to be polished during polishing decreases. For example, when the edge of the object to be polished is positioned on the polishing portion 24 and when the edge is positioned on the groove 23, there may be a difference in the contact area between the object to be polished and the polishing portion 24, and if the number of polishing portions 24 that come into contact with the object to be polished is small, the difference tends to be large. Therefore, there is a problem that polishing pressure applied to each polishing particle 21 is likely to vary during polishing, and polishing accuracy is lowered.

(grinding zone)

The polishing layer 20 has four polishing regions, and two regions are alternately arranged in the first polishing region X and the second polishing region Y along the polishing direction.

The lower limit of the abrasion loss of the first polishing region X in the tamariska abrasion test is preferably 0.05g, and more preferably 0.08 g. On the other hand, the upper limit of the amount of abrasion of the first polishing region X is preferably 0.25g, and more preferably 0.2 g. If the abrasion amount of the first polishing region X is less than the lower limit, the abrasive grains 21 are less likely to fall off. Therefore, there is a problem that the polishing particles 21 exposed on the surface of the first polishing region X are easily passivated and the polishing rate is lowered. On the other hand, if the amount of abrasion in the first polishing region X exceeds the upper limit, the lifetime of the polishing material 1 may be shortened. The amount of abrasion in the first polishing region X or the second polishing region Y can be controlled by the content of the filler, the content of the abrasive grains 21, the type of the binder 22, and the like.

The lower limit of the abrasion loss of the second polishing region Y in the tamariska abrasion test is preferably 0.1g, and more preferably 0.15 g. On the other hand, the upper limit of the amount of abrasion of the second polishing region Y is preferably 0.8g, and more preferably 0.5 g. If the abrasion amount of the second polishing region Y is less than the lower limit, the step difference generated between the first polishing region X and the second polishing region Y becomes too small, and the grip strength improvement effect by the cross resistance is insufficient. On the other hand, if the amount of abrasion in the second polishing region Y exceeds the upper limit, the lifetime of the polishing material 1 may be shortened.

The lower limit of the ratio of the abrasion amount of the second polishing region Y having a large abrasion amount to the abrasion amount of the first polishing region X having a small abrasion amount is 1.1, more preferably 1.5, and still more preferably 2. On the other hand, the upper limit of the ratio of the abrasion loss is 7, more preferably 6, and still more preferably 4. If the ratio of the abrasion loss is less than the lower limit, the step difference generated between the first polishing region X and the second polishing region Y becomes too small, and the grip strength improvement effect by the cross resistance is insufficient. On the other hand, if the ratio of the abrasion amount exceeds the upper limit, the step between the first polishing region X and the second polishing region Y becomes large and the cross resistance becomes excessively large, so that there is a problem that edge chipping or cracking of the object to be polished occurs.

The area of each region is determined by the number of divided regions and the size of the base sheet 10, and the lower limit of the area of each region is preferably 2000mm²More preferably 3000mm². On the other hand, the upper limit of the area of each region is preferably 20000mm²More preferably 15000mm². If the area of each region is smaller than the lower limit, the rear edge of the object to be polished is located while the front edge of the object to be polished moves within the regionIn the other adjacent regions, the cross resistance becomes insufficient. Therefore, there is a problem that the grip strength improving effect by the ride resistance is insufficient. On the other hand, if the area of each region exceeds the upper limit, the distance from the entire object to be polished entering the same region to the movement of the front edge of the object to be polished within the region during polishing may become long. Therefore, the number of times per unit time that the object to be polished crosses between the regions is reduced, and the grip strength improving effect by the crossing resistance is insufficient.

The size of each region is preferably larger than the size of the substrate as the object to be polished, and specifically, each region is preferably sized to include a circle having a diameter of 5cm in a plan view. If the size of each region is equal to or smaller than the size of the substrate as the object to be polished, the trailing edge of the object to be polished is located in another adjacent region when the leading edge of the object to be polished moves within the region, and the cross resistance becomes insufficient. Therefore, there is a problem that the grip strength improving effect by the ride resistance is insufficient.

The areas of the plurality of first polishing regions X may be substantially equal. In addition, the areas of the plurality of second polishing regions Y may be substantially equal to each other. Further, the area of each region of the first polishing region X is substantially equal to the area of each region of the second polishing region Y. That is, the polishing layer 20 is divided by two perpendicular straight lines passing through the center of the surface of the substrate sheet 10, and the first polishing region X and the second polishing region Y may be arranged at substantially equal angular intervals. In this way, the polishing layer 20 alternately has two kinds of polishing regions having different amounts of abrasion in the tambour abrasion test at substantially equal angular intervals, and the object to be polished periodically moves between the polishing regions, whereby a high polishing rate and an effect of suppressing a decrease in polishing efficiency can be further obtained. Here, "the areas of the respective regions are substantially equal" means that the difference between the area of each region and the average area of the plurality of regions is 10% or less.

The lower limit of the ratio of the total area of the first polishing regions X having a small amount of wear to the total area of the second polishing regions Y having a large amount of wear is preferably 0.7, and more preferably 0.9. On the other hand, the upper limit of the total area ratio is preferably 1.3, more preferably 1.1. If the total area ratio is less than the lower limit, the ratio of time for which the object to be polished passes through the first polishing region X having a high surface pressure decreases, and thus there is a problem that the polishing rate decreases. On the other hand, if the total area ratio exceeds the upper limit, the surface pressure applied to the first polishing region X is reduced with respect to a load of the same size, so that there is a problem that the polishing rate is reduced.

(adhesive layer)

The adhesive layer 30 is a layer for fixing the polishing material 1 to a support for supporting the polishing material 1 and attaching the polishing material to a polishing apparatus.

The adhesive used in the adhesive layer 30 is not particularly limited, and examples thereof include: reactive adhesives, instant adhesives, hot melt adhesives, and the like.

The adhesive used in the adhesive layer 30 is preferably an adhesive. By using an adhesive as the adhesive used in the adhesive layer 30, the abrasive 1 can be peeled from the support and reattached, so that the abrasive 1 and the support can be easily reused. Such an adhesive is not particularly limited, and examples thereof include: acrylic adhesives, acrylic-rubber adhesives, natural rubber adhesives, synthetic rubber adhesives such as butyl rubber adhesives, silicone adhesives, polyurethane adhesives, and the like.

The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05mm, more preferably 0.1 mm. The upper limit of the average thickness of the adhesive layer 30 is preferably 0.3mm, and more preferably 0.2 mm. If the average thickness of the adhesive layer 30 is less than the lower limit, the adhesive force is insufficient, and the abrasive 1 may peel off from the support. On the other hand, if the average thickness of the adhesive layer 30 exceeds the upper limit, there is a problem that the workability is deteriorated due to an obstacle or the like when the abrasive material 1 is cut into a desired shape.

< polishing of Flat substrate >

The polishing material 1 can be preferably used for single-side or double-side polishing of a glass substrate as a brittle material or a flat substrate such as sapphire or silicon carbide as a hard brittle material.

Grinding the abrasive material 1 at the fifth grindingThe lower limit of the ratio of the polishing rate to the polishing rate in the first polishing (polishing rate maintenance ratio) is preferably 75%, more preferably 80%, and still more preferably 90%. When the polishing rate maintenance rate is less than the lower limit, there is a problem that the polishing efficiency is lowered due to a decrease in the polishing rate. On the other hand, the upper limit of the polishing rate maintenance rate is not particularly limited, and is preferably larger. Here, the polishing rate means a polishing pressure of 200g/cm for a sapphire substrate having a diameter of 5.08cm, a specific gravity of 3.97 and a c-plane²And a polishing rate per 10-minute polishing was repeated under the conditions of an upper platen rotation speed of-25 rpm, a lower platen rotation speed of 50rpm, and a SUN gear (SUN gear) rotation speed of 8 rpm. Specifically, the polishing rate may be determined by dividing the change in weight (g) of the sapphire substrate before and after polishing by the surface area (μm) of the substrate²) Specific gravity (g/. mu.m) of substrate³) And polishing time (minutes).

< method for producing abrasive Material >

The polishing material 1 can be produced by a step of printing the composition for the first polishing region, a step of printing the composition for the second polishing region, and a step of attaching the adhesive layer 30 to the back surface side of the base sheet 10.

(first polishing region composition printing step)

In the first polishing region composition printing step, the first polishing region X is formed by printing the first polishing region composition.

First, a solution in which the abrasive grains 21, the binder 22 forming material, and the filler in the first polishing region X as the first polishing region composition are dispersed in a solvent is prepared as a coating liquid. The solvent is not particularly limited as long as the material forming the binder 22 is soluble. Specifically, Methyl Ethyl Ketone (MEK), isophorone, terpineol, N-methylpyrrolidone, cyclohexanone, propylene carbonate, and the like can be used. In order to control the viscosity or fluidity of the coating liquid, a diluent such as water, alcohol, ketone, acetate, aromatic compound, or the like may be added.

Then, the first polishing region X is formed on the surface of the substrate sheet 10 by a printing method using the coating liquid. Specifically, a mask having a shape corresponding to the rotational shape of the first polishing region X is prepared, and the coating liquid is printed with the mask interposed therebetween. The printing method may be screen printing, metal mask printing, or the like.

After printing, the coating liquid is heated to be dehydrated and hardened, thereby forming the first polishing region X of the polishing layer 20. Specifically, for example, when the main component of the binder 22 is an inorganic substance, the binder 22 can be formed by drying the coating liquid at room temperature (25 ℃), dehydrating the coating liquid by heating at 70 ℃ to 90 ℃, and then curing the coating liquid at 140 ℃ to 310 ℃. When the main component of the binder 22 is a resin, the coating liquid is cured at 100 ℃ to 150 ℃ for 15 hours or more, thereby forming the binder 22.

(printing step of composition for second polishing region)

In the second polishing region composition printing step, the second polishing region Y is formed by printing the second polishing region composition.

First, a solution in which the second polishing region composition is dispersed in a solvent is prepared as a coating liquid, similarly to the coating liquid in the first polishing region composition printing step. Then, the second polishing region Y of the polishing layer 20 is formed using the coating liquid in the same manner as in the first polishing region composition printing step.

The second polishing region composition printing step may be performed before the first polishing region composition printing step or simultaneously with the first polishing region composition printing step.

(subsequent layer sticking step)

Finally, in the adhesive layer attaching step, an adhesive layer 30 is attached to the back surface of the base sheet 10 to obtain the polishing material 1.

< advantages >

Since the polishing material 1 has two types of polishing regions having different amounts of wear in the tambour wear test, when the polishing material 1 is used for polishing, the second polishing region Y having a large amount of wear in a pair of adjacent polishing regions is worn first. In the polishing material 1, the ratio of the abrasion amount in the second polishing region Y having a large abrasion amount to the abrasion amount in the first polishing region X having a small abrasion amount in the pair of adjacent polishing regions is 1.1 or more, so that an appropriate step difference is generated between the pair of adjacent polishing regions in a short time from the start of polishing, and the surface pressure in the first polishing region X having a small abrasion amount is increased. Thus, the polishing material 1 can more effectively apply the surface pressure during polishing, and thus the polishing rate is high. Further, since the ratio of the abrasion amount of the polishing material 1 is 7 or less, the step is not excessively increased, and the polishing material is divided along the polishing direction, so that the polishing material is polished while crossing the step without being damaged. When the object to be polished crosses the step, the gripping force of the polishing material 1 is increased by so-called crossing resistance of the object to be polished which is pressed to the step, and the surface pressure is increased in a region having a large height, and the surface pressure at the time of polishing can be effectively applied, so that the polishing efficiency of the polishing material 1 is not easily lowered.

[ second embodiment ]

A second embodiment of the present invention will be described in detail below with reference to the accompanying drawings as appropriate.

The polishing material 2 shown in fig. 2 is disk-shaped and mainly includes a substrate sheet 11 and a polishing layer 20 laminated on the surface side of the substrate sheet 11. The polishing material 2 includes an adhesive layer 30 laminated on the back surface side of the base sheet 11. Further, the polishing material 2 includes a support 40 laminated via an adhesive layer 30, and a support adhesive layer 41 laminated on the back surface side of the support 40. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(substrate sheet)

The substrate sheet 11 is a member for supporting the polishing layer 20. The substrate sheet 11 is divided into four pieces along the polishing direction so that the first polishing region X and the second polishing region Y substantially coincide with each other in a plan view. That is, the bottom surface of the groove 23 located at the boundary between adjacent polishing regions is constituted by the surface of the support 40. By dividing the substrate sheet 11 into the polishing regions in this manner, the polishing material 2 can be configured by bonding a plurality of substrate sheets 11 each having the polishing layer 20 having different wear amounts, and therefore, the polishing material 2 can be manufactured more easily than when polishing regions having different wear amounts are formed on one substrate sheet 11.

The material, size, and average thickness of the substrate sheet 11 may be the same as those of the substrate sheet 10 of the first embodiment.

(support)

The support 40 is a plate-shaped member for supporting the substrate sheet 11 and fixing the polishing material 2 to the polishing apparatus.

The material of the support 40 includes: thermoplastic resins such as polypropylene, polyethylene, polytetrafluoroethylene and polyvinyl chloride, and engineering plastics such as polycarbonate, polyamide and polyethylene terephthalate. By using such a material for the support 40, the support 40 has flexibility, and the polishing material 2 follows the surface shape of the object to be polished, so that the polishing surface and the object to be polished are easily brought into contact with each other, and the polishing efficiency is improved.

The average thickness of the support 40 may be set to 0.5mm or more and 3mm or less, for example. If the average thickness of the support 40 is less than the lower limit, there is a problem that the strength of the support 40 is insufficient. On the other hand, if the average thickness of the support 40 exceeds the upper limit, there is a problem that it is difficult to attach the support 40 to a polishing apparatus or a problem that the flexibility of the support 40 is insufficient.

(support adhesive layer)

The support adhesion layer 41 is a layer for attaching the support 40 to a polishing apparatus. The kind and average thickness of the adhesive of the support adhesive layer 41 may be the same as those of the adhesive layer 30.

< method for producing abrasive Material >

The polishing material 2 can be produced by a step of printing the polishing layer composition onto the base sheet 11 for use in two regions, a step of fixing the base sheet 11 to the support 40, and a step of attaching the support adhesive layer 41.

(printing Process)

In the printing step, the polishing layer composition is printed for use in two types of regions, and the base sheet 11 on which the polishing layer 20 for the first polishing region X is formed and the base sheet 11 on which the polishing layer 20 for the second polishing region Y is formed are prepared.

In the printing step, first, a solution in which the first polishing region composition is dispersed in a solvent and a solution in which the second polishing region composition is dispersed in a solvent are prepared as coating liquids, respectively, in the same manner as in the first embodiment.

Then, the polishing layer composition was printed using these coating liquids for two areas. Specifically, two base material sheets 11 are prepared for each region. Further, a mask corresponding to the substrate sheet 11 is prepared, and the first polishing area composition and the second polishing area composition are printed on each substrate sheet 11 with the mask interposed therebetween. Further, in order to form the groove 23, the mask has a shape corresponding to the shape of the groove 23. In addition, the printing method may be the same as the first embodiment.

(substrate sheet sticking step)

In the base sheet sticking step, the base sheet 11 on which the polishing layer 20 is formed is cut so as to conform to the shape of each region of the polishing material 2, and is bonded to the support 40 via the bonding layer 30.

(Process for attaching support adhesive layer)

Finally, in the step of attaching a support adhesive layer, a support adhesive layer 41 is attached to the back surface of the support 40 to obtain the polishing material 2.

< advantages >

The abrasive 2 is provided with a support 40, and thus handling of the abrasive 2 is facilitated.

[ other embodiments ]

The present invention is not limited to the above-described embodiments, and can be implemented in various modifications and improvements other than the above-described embodiments.

In the above embodiment, the case where the polishing material has a disk shape was described, but the shape of the polishing material is not limited to a disk shape. For example, the abrasive material may be square. The size of the case where the polishing material is square is not particularly limited, and may be square with one side of 140mm to 160mm, for example.

In the above embodiment, the grooves are formed in a lattice shape, that is, the planar shape of the polishing portion is a square shape, but the planar shape of the polishing portion may not be a square shape, and may be a shape in which polygons other than a square are repeated, a circular shape, or the like.

The polishing material may have a structure without grooves.

In the above embodiment, the polishing material including two types of polishing regions having different amounts of abrasion in the tamariskoid test was described, but the number of polishing regions having different amounts of abrasion is not limited to two types, and the number of polishing regions having different amounts of abrasion may be three or more.

In the case where the number of polishing regions is three or more, a plurality of combinations may exist between a pair of adjacent polishing regions as long as the ratio of the abrasion loss amounts is 1.1 or more and 7 or less for at least the one set of adjacent pair of polishing regions. The arrangement order of the polishing direction with respect to the polishing region is not particularly limited. For example, in the case where the polishing regions are three types, i.e., the first polishing region (a), the second polishing region (B), and the third polishing region (C), in ascending order of abrasion loss, the polishing regions may be arranged in a minimum unit such as a-B-C-a-B-C, or in a gentle change such as a-B-C-B-a. In addition, the plurality of kinds of polishing regions may be arranged in an irregular order without being arranged repeatedly.

In the above embodiment, the substrate sheet is divided into four in the circumferential direction as each polishing region, but the number of divisions is not limited to 4, and may be divided into two, three, or five or more. The lower limit of the number of divisions is preferably 4. If the number of divisions is less than the lower limit, the number of times per unit time that the object to be polished crosses over polishing regions having different amounts of abrasion during polishing decreases, and thus the gripping force improvement effect by the crossing resistance is insufficient.

In the first embodiment, the case where the polishing material has the adhesive layer is described, but the adhesive layer is not essential and may be omitted. For example, the adhesive layer may be located on the support side, or may be fixed to the support by other fixing methods such as screw fixation.

In the above embodiment, the case where the grooves are spaces has been described, but the polishing material may be provided with a filling portion for filling the grooves. The filling part preferably contains a resin or an inorganic substance as a main component and does not substantially contain abrasive grains. The term "a filling portion substantially free of abrasive grains" means that the content of abrasive grains is less than 0.001 vol%, preferably less than 0.0001 vol%.

When the polishing material includes a filler, the lower limit of the ratio of the average thickness of the filler to the average thickness of the polishing layer is preferably 0.1, more preferably 0.5, even more preferably 0.8, and particularly preferably 0.95. On the other hand, the upper limit of the ratio of the average thickness of the filling portion is preferably 1, and more preferably 0.98. If the ratio of the average thickness of the filling portion is less than the lower limit, there is a problem that the effect of suppressing the object to be polished from falling into the groove during polishing becomes insufficient. On the other hand, if the ratio of the average thickness of the filler exceeds the upper limit, there is a problem that the polishing layer does not sufficiently contact the object to be polished at the start of polishing, or the polishing pressure applied to the polishing layer is insufficient due to the polishing pressure being dispersed in the filler. The "average thickness of the filling portion" herein means an average value of the distance between the surface of the base material and the surface of the filling portion.

Examples

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[ example 1]

Diamond abrasives were prepared, and the average particle diameter was measured using Mickey (Microtrac) MT3300EXII, manufactured by Nikkiso Co. The diamond abrasive grains had an average grain size of 44 μm. Further, the kind of diamond of the abrasive grains was treated diamond coated with 55 mass% nickel.

Silicic acid as adhesiveSodium (sodium silicate No. 3), the diamond abrasive grains, and alumina (Al) as a filler₂O₃Average particle size 12 μm) were mixed, and prepared so that the content of diamond abrasive grains in the polishing layer became 5 vol% and the content of filler in the polishing layer became 71 vol%, to obtain a first coating liquid for polishing regions.

Without preparing diamond abrasive grains, sodium silicate (sodium silicate No. 3) as a binder and alumina (average particle size 14 μm) as a filler were mixed so that the content of the filler in the polishing layer became 67 vol%, and a coating liquid for a second polishing region was obtained.

A disk-shaped aluminum plate having an average thickness of 300 μm, an outer diameter of 386mm and an inner diameter of 148mm was prepared as a substrate sheet. The surface of the base material sheet was divided into eight regions by four straight lines passing through the center of the surface of the base material sheet and forming an angle of 45 degrees with the adjacent straight lines, and the polishing layers were formed so that two types of polishing regions having different amounts of abrasion in the taber abrasion test were alternately arranged in the circumferential direction. Specifically, the polishing layer is formed as follows. First, four second polishing regions are formed by printing using the second polishing region coating liquid. The printing uses a mask having a pattern corresponding to the rotational shape of the polishing portion of the second polishing region. Each polishing portion had a square shape with a side of 1.5mm in a plan view, and the width of the groove was 3.5 mm. The average thickness of the polishing portion was 500 μm. The polishing portion is in a square pattern shape regularly arranged. Further, the polishing region has a size capable of containing a circle having a diameter of 8.5cm in a plan view. The coating liquid is dried at room temperature (25 ℃), dehydrated by heating at 80 ℃, and then cured at 300 ℃ for 2 to 4 hours. Then, as in the second polishing regions, four first polishing regions are formed between the second polishing regions by printing using the first polishing region coating liquid.

In addition, a hard vinyl chloride resin plate having an average thickness of 1mm was used as a support for supporting the substrate sheet and fixed to a support of a polishing apparatus, and the back surface of the substrate sheet was bonded to the surface of the support with an adhesive having an average thickness of 130 μm. Double-sided adhesive tape was used as the adhesive. Thus, the abrasive of example 1 was obtained.

[ example 2]

The abrasive material of example 2 was obtained in the same manner as in example 1 except that diamond abrasive grains were added to the second polishing region coating liquid of example 1 so that the content of the diamond abrasive grains in the polishing layer was 5 vol% and the content of the filler in the polishing layer was 75 vol%.

[ example 3]

The same coating liquid as the first polishing-region coating liquid of example 1 was prepared as a second polishing-region coating liquid. In addition, acidic water prepared by mixing acetic acid (reagent first stage) and ion-exchanged water so that the pH at 20 ℃ becomes 1.6 was prepared. After four second polishing regions were formed by printing using the coating liquid, the second polishing regions were immersed in the acidic water at 70 ℃ for 1 day before the first polishing regions were formed. Except for the above, the abrasive of example 3 was obtained in the same manner as in example 1.

[ example 4]

The polishing material of example 4 was obtained in the same manner as in example 2 except that the coating liquid for the second polishing region in example 2 was prepared so that the content of the diamond abrasive grains in the polishing layer was 5 vol% and the content of the filler in the polishing layer was 81 vol%.

[ example 5]

The polishing material of example 5 was obtained in the same manner as in example 1 except that the coating liquid for the second polishing region of example 1 was prepared so that the content of the filler in the polishing layer was 85 vol%.

[ example 6]

An epoxy resin as a binder, diamond abrasive grains (average grain size 9 μm, single crystal), and alumina (average grain size 2.0 μm) as a filler were mixed, and prepared so that the content of the diamond abrasive grains in the polishing layer was 5 vol% and the content of the filler in the polishing layer was 55 vol%, to obtain a first coating liquid for a polishing region.

The same epoxy resin, diamond abrasive grains, and alumina as those used for the first polishing region were mixed, and prepared so that the content of the diamond abrasive grains in the polishing layer was 5 vol% and the content of the filler in the polishing layer was 60 vol%, to obtain a coating liquid for the second polishing region.

A disk-shaped PET film having an average thickness of 75 μm, an outer diameter of 290mm and an inner diameter of 103mm was prepared as a substrate sheet. The surface of the base material sheet was divided into four regions by two straight lines passing through the center of the surface of the base material sheet and forming an angle of 90 degrees with the adjacent straight lines, and the polishing layer was formed so that two types of polishing regions having different amounts of abrasion in the taber abrasion test were alternately arranged in the circumferential direction. Specifically, a polishing layer was formed in the same manner as in example 1. Further, each polishing portion had a square shape with a side of 2.5mm in a plan view and a groove width of 5 mm. The coating liquids were each cured by heating at 120 ℃.

In addition, a support sheet was bonded to a support fixed to a polishing apparatus in the same manner as in example 1, to obtain a polishing material of example 6.

Comparative example 1

A polishing material of comparative example 1 was obtained in the same manner as in example 1, except that the same coating liquid as the first polishing region coating liquid of example 1 was used to form a polishing layer on the entire surface of the substrate sheet. That is, the polishing layer of the polishing material of comparative example 1 had no region having different amounts of wear.

Comparative example 2

A polishing material of comparative example 2 was obtained in the same manner as in example 2 except that the coating liquid for the second polishing region in example 2 was prepared so that the content of diamond abrasive grains in the polishing layer was 5 vol% and the content of the filler in the polishing layer was 84 vol%.

Comparative example 3

A polishing material of comparative example 3 was obtained in the same manner as in example 6, except that the same coating liquid as the first polishing region coating liquid of example 6 was used to form a polishing layer on the entire surface of the substrate sheet. That is, with the polishing material of comparative example 3, the polishing layer had no region having different amounts of wear.

[ polishing conditions ]

The sapphire substrate was polished using the polishing materials obtained in examples 1 to 5 and comparative examples 1 to 2. In example 6 and comparative example 3, the glass substrate was polished using an abrasive. Each polishing condition is shown below.

< conditions for grinding sapphire substrate >

For the sapphire substrate, a sapphire substrate having a diameter of 5.08cm, a specific gravity of 3.97, and a c-plane (treated only by grinding (as-lap)) was used. In the grinding, a commercially available double-side grinder was used. The carrier of the double-side grinder is epoxy glass with the thickness of 0.4 mm. For polishing, the polishing pressure was set to 200g/cm²The polishing was performed 5 times in 10 minutes using conditions of an upper platen rotation speed of-25 rpm, a lower platen rotation speed of 50rpm, and a sun gear rotation speed of 8 rpm. At this time, "Daphne Cut (GS 50K)" of Daphne Kagaku Co., Ltd, was supplied as a coolant (coolant) at 30cc per minute.

< conditions for polishing glass substrate >

For the glass substrate, synthetic quartz glass having a diameter of 5.08cm and a specific gravity of 2.19 was used. In the grinding, a commercially available double-side grinder was used. The carrier of the double-side grinder was a vinyl chloride resin plate having a thickness of 0.6 mm. For polishing, the polishing pressure was set to 100g/cm²The polishing was performed 5 times in 10 minutes using the conditions of the upper platen rotation speed of 40rpm, the lower platen rotation speed of 60rpm, and the sun gear rotation speed of 30 rpm. At this time, 120cc of water was supplied per minute as a coolant, and the coolant was obtained by diluting "GC-50P" of Wu corporation, Inc. (Noritake Company Limited) by 30 times.

[ evaluation method ]

The polishing materials of examples 1 to 6 and comparative examples 1 to 3 were measured for the amount of abrasion by the tamariskoid abrasion test, and for the polishing rate and the maintenance rate when the substrate was polished using these polishing materials. The results are shown in table 1.

< measurement of abrasion loss >

In the measurement of the abrasion loss by the Taber abrasion test, test pieces (average diameter 104mm and average thickness 300 μm) corresponding to the first polishing region and the second polishing region of the polishing materials of examples 1 to 6 and comparative examples 1 to 3 were prepared, respectively. The test piece was abraded by rotating 320 using a Taber abrasion tester ("MODEL 174" from Taber Instrument) under the condition of an abrasion wheel H-18 and a load of 4.9N (500 gf). The difference [ g ] in mass of the test piece before and after 320 revolutions was measured as the abrasion loss [ g ]. The abrasion ratio is calculated by dividing the amount of abrasion in the second polishing region by the amount of abrasion in the first polishing region.

< polishing Rate >

In calculating the polishing rate, a sapphire substrate or a glass substrate subjected to first polishing for 10 minutes was used. The polishing rate is the weight change (g) of the substrate before and after polishing divided by the surface area (cm) of the substrate²) Specific gravity (g/cm) of the substrate³) And polishing time (minutes).

< maintenance Rate >

The maintenance ratio of the polishing rate was calculated by dividing the polishing rate at the time of the fifth polishing by the polishing rate at the time of the first polishing.

[ Table 1]

In Table 1, "-" in the column of the second polishing region and the abrasion ratio means that the polishing materials do not have polishing regions having different amounts of abrasion. In addition, "-" in the column of results means that edge chipping or cracking of the substrate occurred, and the polishing rate could not be measured.

From the results shown in Table 1, the polishing rates of the polishing materials of examples 1 to 6 were less likely to decrease than those of comparative examples 1 to 3. In contrast, since the polishing materials of comparative examples 1 and 3 do not have polishing regions having different amounts of wear, it is considered that the grip strength improving effect by the cross resistance cannot be obtained and the polishing rate is lowered. In the polishing material of comparative example 2, since the abrasion ratio exceeded 7, it is considered that the step difference between the first polishing region and the second polishing region became large and the cross resistance became excessively large, and edge chipping or cracking of the object to be polished occurred.

In addition, when examples 2 to 4 in which the same kind of substrates having the same content of abrasive grains were polished were compared with comparative example 1, the polishing materials of examples 2 and 3 were excellent in polishing rate, and the polishing materials of example 4 were equal in polishing rate. Here, the polishing material of comparative example 1 is a previous polishing material having a polishing portion in which diamond abrasive grains and a filler are dispersed, and thus the polishing rate is increased. From this, it was found that the polishing materials of examples 2 to 4 had high polishing rates.

From the above, it is known that: the polishing layer has a plurality of types of polishing regions having different amounts of wear, and the polishing material has a high polishing rate and excellent maintenance of the polishing rate by setting the ratio of the amount of wear of a polishing region having a large amount of wear to the amount of wear of a polishing region having a small amount of wear of a pair of adjacent polishing regions to 1.1 or more and 7 or less.

Industrial applicability

The polishing material of the present invention has a high polishing rate and is less likely to decrease in polishing efficiency. Therefore, the polishing material can be preferably used for polishing a substrate difficult to process such as glass, sapphire, and silicon carbide.

Claims

1. A polishing material comprising a substrate sheet and a polishing layer laminated on the surface side of the substrate sheet and containing polishing particles and a binder therefor, wherein

The polishing layer is divided along the polishing direction and has a plurality of kinds of polishing regions having different amounts of abrasion in a Taber abrasion test,

the ratio of the abrasion amount of the polishing region having a large abrasion amount to the abrasion amount of the polishing region having a small abrasion amount in a pair of adjacent polishing regions is 1.1 or more and 7 or less,

each of the polishing regions has a size capable of containing a circle having a diameter of 5cm in a plan view.

2. The polishing material according to claim 1, wherein the polishing regions are two types and arranged alternately in the polishing direction.

3. The abrasive according to claim 1, wherein the binder contains a filler containing an inorganic oxide as a main component, and

the average particle diameter of the filler is smaller than the average particle diameter of the abrasive grains.

4. The polishing material according to claim 1, wherein the two kinds of polishing regions are alternately arranged along the polishing direction, the binder contains a filler containing an inorganic oxide as a main component, and