JP6859035B2 - Abrasive - Google Patents

Description

The present invention relates to an abrasive.

In recent years, the precision of electronic devices such as hard disks has been advancing. As the substrate material for such electronic devices, glass, sapphire, etc. are used in consideration of rigidity, impact resistance, and heat resistance that can be reduced in size and thickness. A polishing pad with fixed abrasive grains is generally used for processing such a substrate.

By the way, in the above-mentioned substrate processing, improvement of processing efficiency is required. As an abrasive that can improve the processing efficiency of substrate processing, for example, an abrasive in which a plurality of independent polishing structures are formed as polishing layers on the surface of a base sheet has been proposed (Japanese Patent Laid-Open No. 2009-72832). See publication). In this polishing material, the polishing pressure is increased and the grinding force is improved by reducing the area ratio of the polishing surface of the polishing structure to the polishing layer and reducing the area of the polishing surface that receives the polishing load applied at the time of polishing.

In the above-mentioned conventional abrasive, the area ratio is controlled by providing a groove between a plurality of polishing structures. Therefore, in order to reduce the area ratio and improve the grinding force, it is necessary to widen the groove width between the polished structures. When the groove width is widened in this way, when the end portion of the substrate (work piece) crosses the groove during polishing, the end portion of the substrate tends to tilt toward the base sheet side. For this reason, the substrate is caught in the upper part of the side surface of the groove or falls into the groove, so that the frequency of scratches on the substrate increases.

JP-A-2009-72832

The present invention has been made in view of such inconveniences, and an object of the present invention is to provide an abrasive material capable of achieving relatively high processing efficiency while suppressing damage due to a drop of a work piece into a groove or the like.

The invention made to solve the above problems is a polishing material including a base material and a polishing layer laminated on the surface side of the base material, wherein the polishing layer contains abrasive grains and a binder thereof. In addition, it has a plurality of types of polishing parts having different amounts of wear in the Taber wear test, and among the above-mentioned plurality of types of polishing parts, the first polishing part having the smallest amount of wear is surrounded by another polishing part, and the first polishing part is surrounded. The ratio of the amount of wear of the other polished part to the amount of wear of the part is 3 or more, and the occupied area ratio of the entire polished part in the polishing layer is 15% or more and 100% or less.

The abrasive material includes a first polishing portion and another polishing portion surrounding the first polishing portion, and the ratio of the wear amount of the other polishing portion to the wear amount of the first polishing portion in the taber wear test is the above. It is above the lower limit. Therefore, when polishing is performed using the polishing material, the other polishing portions surrounding the first polishing portion are worn first. As a result, in a relatively short time from the start of polishing, a step is formed between the first polishing portion and the other polishing portion so that the other polishing portion has a low height. Further, since the wear of the polished portion progresses mainly in the first polished portion and the other polished portions due to the spillage of the abrasive grains, the work piece is polished while maintaining this step. Therefore, since the first polishing portion mainly receives the polishing load applied at the time of polishing, the polishing pressure of the first polishing portion is increased, thereby increasing the grinding force of the abrasive material. Further, in the polishing material, the other polishing portion surrounds the first polishing portion, and the occupied area ratio of the entire polishing portion in the polishing layer is within the above range. Therefore, in the abrasive material, when the end portion of the work piece moves between the first polishing parts during polishing, the work piece can be prevented from being tilted toward the base material by the other polishing parts. Therefore, the abrasive can suppress damage due to the falling into the groove or the like of the work piece.

The occupied area ratio of the first polished portion in the polishing layer is preferably 3% or more and 16% or less. By setting the occupied area ratio of the first polishing portion within the above range, the polishing pressure received by the first polishing portion can be increased, and the grinding force of the abrasive can be further improved.

It is preferable that the abrasive grains of the first polishing portion are composed of a plurality of types of abrasive grains. By forming the abrasive grains of the first polishing portion with a plurality of types of abrasive grains in this way, it is possible to improve the grinding force while suppressing an increase in the manufacturing cost of the abrasive material.

The first polishing portion preferably contains diamond abrasive grains, and the content of the diamond abrasive grains in the first polishing portion is preferably 1% by volume or more and 20% by volume or less. By setting the content of diamond abrasive grains in the first polishing portion within the above range in this way, it is possible to further improve the grinding force while suppressing an increase in the manufacturing cost of the abrasive.

The content of the diamond abrasive grains in the other polishing portion is preferably 0.3% by volume or less. Since diamond abrasive grains are hard and have high grinding power, they are less likely to cause blinding or spillage even when they come into contact with the work piece, and are more susceptible to a large polishing load than other abrasive grains. Therefore, by setting the content of diamond abrasive grains in the other polishing parts to the above upper limit or less, it is possible to prevent the polishing load from being applied to the other polishing parts during polishing and to easily concentrate on the first polishing part. , The grinding power of the abrasive can be improved. The content of the diamond abrasive grains is 0% by volume, that is, the other polishing portion does not have to contain the diamond abrasive grains.

Here, the "amount of wear in the Taber wear test" is determined by preparing a test piece (average diameter 104 mm, average thickness 300 μm), using a Taber wear tester, and using a Taber wear tester under the conditions of a wear wheel H-18 and a load of 4.9 N (500 gf). It is a value obtained by rotating the test piece 320 times and measuring the mass difference of the test piece before and after 320 rotations. Further, "the first polishing portion is surrounded by another polishing portion" means that the first polishing portion is located in a closed space formed by the other polishing portions in a plan view. The other polishing portion may be continuously present on the outer periphery of the closed space, but may have an intermittent portion within a range of 10% or less of the total circumference. If the other polished part has an intermittent part, the intermittent part shall determine the area of the closed space by extrapolation. When there is such an intermittent portion, the first polished portion may be partially located in the closed space, but the area of the first polished portion located in the closed space in a plan view is the entire area of the first polished portion. When occupying 50% or more of the area, it is determined that the first polished portion is located in a closed space. Further, the "abrasive layer area" is a concept including the area of the groove when the polishing layer has a groove.

As described above, the abrasive material of the present invention can achieve relatively high processing efficiency while suppressing damage due to a drop of the work piece into a groove or the like.

It is a schematic partial plan view which shows the abrasive material which concerns on embodiment of this invention. FIG. 5 is a schematic partial cross-sectional view taken along the line AA of FIG. It is a schematic partial plan view which shows the abrasive material different from FIG. It is a schematic plan view which shows the structure of the polishing part of the abrasive material different from FIG. 1 and FIG. It is a schematic plan view which shows the structure of the polishing part of the abrasive material different from FIG. 1, FIG. 3 and FIG. It is a schematic plan view which shows the structure of the polishing part of the abrasive material different from FIG. 1, FIG. 3 to FIG. It is a schematic plan view which shows the structure of the polishing part of the abrasive material different from FIG. 1, FIG. 3 to FIG. It is a schematic plan view which shows the structure of the polishing part of the abrasive material different from FIG. 1, FIG. 3 to FIG. It is a schematic cross-sectional view which shows the abrasive material which concerns on embodiment different from FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

The abrasive 1 shown in FIGS. 1 and 2 includes a base material 10, a polishing layer 20 laminated on the front surface side of the base material 10, and an adhesive layer 30 laminated on the back surface side of the base material 10. .. The abrasive 1 is used, for example, as a fixed abrasive grain abrasive for substrate processing.

〔Base material〕
The base material 10 is a plate-shaped member for supporting the polishing layer 20.

The main component of the base material 10 is not particularly limited, and examples thereof include polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), polyimide (PI), polyethylene naphthalate (PEN), aramid, aluminum, and copper. Be done. Of these, PET and aluminum, which have good adhesiveness to the polishing layer 20, are preferable. Further, the surface of the base material 10 may be subjected to a treatment such as a chemical treatment, a corona treatment, a primer treatment or the like to improve the adhesiveness. Here, the "main component" means a component having the highest content, for example, a component having a content of 50% by mass or more, preferably 90% or more.

Further, the base material 10 is preferably flexible or ductile. Since the base material 10 has flexibility or ductility in this way, the abrasive material 1 follows the surface shape of the work piece, and the contact area between the polished surface and the work piece increases, so that the polishing rate increases. Further increase. Examples of the main component of the base material 10 having such flexibility include PET and PI. Moreover, as the main component of the base material 10 having ductility, aluminum, copper and the like can be mentioned.

The shape and size of the base material 10 are not particularly limited, but may be, for example, a square shape having a side of 140 mm or more and 160 mm or less, or an annular shape having an outer diameter of 200 mm or more and 2100 mm or less and an inner diameter of 100 mm or more and 660 mm or less. Further, a plurality of base materials 10 juxtaposed on a plane may be supported by a single support.

The average thickness of the base material 10 is not particularly limited, but can be, for example, 50 μm or more and 1 mm or less. If the average thickness of the base material 10 is less than the above lower limit, the strength and flatness of the abrasive 1 may be insufficient. On the contrary, when the average thickness of the base material 10 exceeds the upper limit, the abrasive 1 may become unnecessarily thick and difficult to handle.

[Abrasive layer]
The polishing layer 20 has two types of polishing portions having different amounts of wear in the Taber wear test. Of the two types of polishing parts, the first polishing part 21 having a small amount of wear is surrounded by the second polishing part 22 having a large amount of wear. Further, the second polishing portion 22 is independent of each other and is separated by a groove 23. Further, the second polishing section 22 surrounds one first polishing section 21, and there is no gap between the first polishing section 21 and the second polishing section 22. That is, the convex portion 24 is formed by the first polishing portion 21 and the second polishing portion 22.

The lower limit of the average thickness of the polishing layer 20 (the average thickness of only the convex portion 24 portion) is preferably 25 μm, more preferably 30 μm, and even more preferably 50 μm. On the other hand, the upper limit of the average thickness of the polishing layer 20 is preferably 4000 μm, more preferably 3500 μm, and even more preferably 3000 μm. If the average thickness of the polishing layer 20 is less than the above lower limit, the durability of the polishing layer 20 may be insufficient. On the contrary, if the average thickness of the polishing layer 20 exceeds the upper limit, the homogeneity of the polishing layer 20 is lowered, which may make it difficult to exert a stable grinding force. In addition, the abrasive material 1 may become unnecessarily thick, making it difficult to handle and increasing the manufacturing cost.

<1st polishing part>
The first polishing unit 21 includes abrasive grains 21a and a binder 21b thereof. The plan view shape of the first polishing portion 21 is not particularly limited, but may be a square shape or a circular shape. Further, the plurality of first polishing portions 21 are arranged in a regular block pattern.

(Abrasive grain)
Examples of the abrasive grains 21a of the first polishing unit 21 include diamond abrasive grains, alumina abrasive grains, silica abrasive grains, ceria abrasive grains, silicon carbide abrasive grains, and boron carbide abrasive grains.

The lower limit of the content of the abrasive grains 21a in the first polishing unit 21 is preferably 50% by volume, more preferably 60% by volume. On the other hand, as the upper limit of the content of the abrasive grains 21a, 85% by volume is preferable, and 80% by volume is more preferable. When the content of the abrasive grains 21a is less than the above lower limit, the content of the binder 21b is relatively large, so that the abrasive grains 21a are firmly fixed and it is difficult for the eyes to spill. For this reason, the abrasive grains 21a exposed on the surface of the first polishing portion 21 are likely to be crushed, and the polishing rate may decrease. On the contrary, when the content of the abrasive grains 21a exceeds the upper limit, the content of the binder 21b becomes relatively small, so that the abrasive grains 21a are likely to spill. Therefore, the polishing rate may decrease due to this eye spill.

The average particle size of the abrasive grains 21a of the first polishing unit 21 is appropriately selected from the viewpoint of the polishing rate and the surface roughness of the work piece after polishing. The lower limit of the average particle size of the abrasive grains 21a is preferably 1 μm, more preferably 2 μm. On the other hand, the upper limit of the average particle size of the abrasive grains 21a is preferably 45 μm, more preferably 40 μm. If the average particle size of the abrasive grains 21a is less than the above lower limit, the grinding force of the abrasive 1 may be insufficient and the processing efficiency may decrease. On the contrary, if the average particle size of the abrasive grains 21a exceeds the upper limit, the polishing accuracy may decrease. Here, the "average particle size" means a 50% value (50% particle size, D50) of the volume-based cumulative particle size distribution curve measured by a laser diffraction method or the like.

The abrasive grains 21a of the first polishing unit 21 may be composed of one type of abrasive grains, but is preferably composed of a plurality of types of abrasive grains. By forming the abrasive grains 21a of the first polishing unit 21 with a plurality of types of abrasive grains in this way, it is possible to improve the grinding force while suppressing an increase in the manufacturing cost of the abrasive material 1.

When the abrasive grains 21a are composed of a plurality of types of abrasive grains, the abrasive grains 21a preferably include diamond abrasive grains, and particularly preferably the abrasive grains 21a are composed of a diamond grindstone and alumina abrasive grains. .. Diamond abrasive grains have higher grinding power than other abrasive grains, but are expensive. Therefore, by using one of the plurality of types of abrasive grains as diamond abrasive grains, it is possible to further improve the grinding force while suppressing an increase in manufacturing cost. Further, since the alumina abrasive grains are relatively inexpensive, the effect of reducing the manufacturing cost can be enhanced by forming the abrasive grains 21a with the diamond grindstone and the alumina abrasive grains.

The diamond of the diamond abrasive grains may be a single crystal or a polycrystal, or may be a diamond treated with Ni coating or the like. Of these, single crystal diamond and polycrystalline diamond are preferable. Single crystal diamond is the hardest of all diamonds and has high grinding power. Further, since polycrystalline diamond is easy to cleave in the microcrystalline unit constituting the polycrystalline and the blinding is hard to proceed, the decrease in the polishing rate is small.

When the abrasive grains 21a are composed of a plurality of types of abrasive grains including diamond abrasive grains, the lower limit of the content of the diamond abrasive grains in the first polishing portion 21 is preferably 1% by volume, more preferably 2% by volume. preferable. On the other hand, the upper limit of the content of the diamond abrasive grains is preferably 20% by volume, more preferably 8% by volume. If the content of the diamond abrasive grains is less than the above lower limit, the grinding force of the abrasive 1 may be insufficient. On the contrary, if the content of the diamond abrasive grains exceeds the upper limit, the effect of suppressing an increase in the manufacturing cost of the abrasive 1 may be insufficient.

Further, when the abrasive grains 21a are composed of a plurality of types of abrasive grains including diamond abrasive grains, the average particle size of the diamond abrasive grains is larger than the average particle size of the other abrasive grains excluding the diamond abrasive grains. Is preferable. The lower limit of the ratio of the average particle size of the diamond abrasive grains to the average particle size of the other abrasive grains excluding the diamond abrasive grains is preferably 1.3, more preferably 1.5. On the other hand, as the upper limit of the ratio of the average particle size, 20 is preferable, and 10 is more preferable. When the ratio of the average particle diameter is less than the above lower limit, the polishing pressure applied to the abrasive grains other than the diamond abrasive grains becomes large, and the polishing pressure applied to the diamond abrasive grains having a high grinding force becomes relatively small, so that the polishing rate May decrease. On the contrary, when the ratio of the average particle diameter exceeds the above upper limit, the abrasive grains other than the diamond abrasive grains are excessively spilled. The life of 1 may be shortened.

(binder)
The main component of the binder 21b of the first polishing portion 21 is not particularly limited, but may be, for example, a resin or an inorganic substance.

Examples of the resin include resins such as polyurethane, polyphenol, epoxy, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacrylic, acrylic ester, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, and polyamide. The resin may be at least partially crosslinked.

Examples of the inorganic substance include silicates, phosphates, polyvalent metal alkoxides and the like.

The main component of the binder 21b is preferably an inorganic substance. Of these, silicates with high abrasive grain retention are preferable. Examples of such a silicate include sodium silicate and potassium silicate.

The binder 21b may appropriately contain various auxiliary agents and additives such as a dispersant, a coupling agent, a surfactant, a lubricant, a defoaming agent, and a colorant, depending on the purpose.

As the lower limit of the average area of each first polishing portion 21, 1 mm ² is preferable, and 2 mm ² is more preferable. On the other hand, as the upper limit of the average area of the first polishing portion 21, 150 mm ² is preferable, and 130 mm ² is more preferable. If the average area of the first polishing portion 21 is less than the above lower limit, the first polishing portion 21 may peel off from the base material 10. On the contrary, when the average area of the first polishing portion 21 exceeds the upper limit, the number of the first polishing portions 21 that come into contact with the work piece during polishing decreases. For example, there may be a difference in the contact area between the work piece and the first polishing part 21 between the case where the peripheral edge of the work piece is located on the first polishing part 21 and the case where it is located on the groove 23. When the number of the first polishing portions 21 in contact with the machined body is small, this difference tends to be large. Therefore, the polishing pressure applied to each abrasive grain 21a tends to fluctuate during polishing, which may reduce the polishing accuracy.

As the lower limit of the occupied area ratio of the first polishing portion 21 in the polishing layer 20, 3% is preferable, and 4% is more preferable. On the other hand, the upper limit of the occupied area ratio of the first polishing portion 21 is preferably 16%, more preferably 10%, and even more preferably 9.5%. If the occupied area ratio of the first polishing portion 21 is less than the above lower limit, the polishing pressure applied to the first polishing portion 21 during polishing becomes too high, and the abrasive grains 21a are likely to fall off, so that the polishing rate may decrease. is there. On the contrary, if the occupied area ratio of the first polishing portion 21 exceeds the above upper limit, the polishing rate improving effect due to the increase in the polishing pressure of the first polishing portion 21 may be insufficient.

As the lower limit of the distance between the adjacent first polishing portions 21 (distance between the centers of the first polishing portions 21), 3 mm is preferable, and 5 mm is more preferable. On the other hand, the upper limit of the distance between the first polishing portions 21 is preferably 50 mm, more preferably 40 mm. If the distance between the first polishing portions 21 is less than the above lower limit, it becomes difficult to reduce the area of each first polishing portion 21 while suppressing peeling from the base material 10, so that the first polishing The occupied area ratio of the portion 21 cannot be sufficiently reduced, and the polishing rate improving effect may be insufficient. On the contrary, when the distance between the first polishing parts 21 exceeds the above upper limit, the occupied area ratio of the first polishing part 21 is too low, the first polishing part 21 is worn quickly, and the life of the polishing material 1 is extended. It may be shortened.

The lower limit of the amount of wear of the first polishing portion 21 in the Taber wear test is preferably 0.05 g, more preferably 0.08 g. On the other hand, as the upper limit of the amount of wear of the first polishing portion 21 in the Taber wear test, 0.15 g is preferable, and 0.13 g is more preferable. If the amount of wear of the first polishing portion 21 is less than the above lower limit, the abrasive grains 21a are less likely to spill. For this reason, the abrasive grains 21a exposed on the surface of the first polishing portion 21 are likely to be crushed, and the polishing rate may decrease. On the contrary, if the amount of wear of the first abrasive portion 21 exceeds the upper limit, the life of the abrasive material 1 may be shortened. The amount of wear of the first polishing unit 21 can be controlled mainly by the content of the abrasive grains 21a of the first polishing unit 21 and the type of the binder 21b.

<Second polishing part>
The second polishing unit 22 includes abrasive grains 22a and a binder 22b thereof. The second polishing portion 22 surrounds the entire circumference of the first polishing portion 21, and the inner circumference thereof coincides with the circumference of the first polishing portion 21. That is, the shape formed by the inner circumference of the second polishing portion 22 is the same as the plan-view shape of the first polishing portion 21. Further, the shape formed by the outer circumference of the second polishing portion 22 (the plan-view shape of the convex portion 24) is not particularly limited, but as shown in FIG. 1, the center of gravity coincides with and is similar to that of the first polishing portion 21. Can be shaped like this.

(Abrasive grain)
As the abrasive grains 22a of the second polishing section 22, the same abrasive grains as the abrasive grains 21a of the first polishing section 21 can be mentioned.

The lower limit of the content of the abrasive grains 22a in the second polishing portion 22 is preferably 60% by volume, more preferably 70% by volume. On the other hand, as the upper limit of the content of the abrasive grains 22a, 95% by volume is preferable, and 80% by volume is more preferable. When the content of the abrasive grains 22a is less than the above lower limit, the content of the binder 22b is relatively large, so that the abrasive grains 22a are firmly fixed and it is difficult for the eyes to spill. Therefore, the amount of wear of the second polishing portion 22 is reduced, and it is difficult for a difference in the amount of wear to occur between the second polishing portion 22 and the first polishing portion 21 during polishing. As a result, the polishing pressure of the first polishing unit 21 cannot be sufficiently increased, and the effect of improving the polishing rate may be insufficient. On the contrary, if the content of the abrasive grains 22a exceeds the above upper limit, the content of the binder 22b is insufficient and the abrasive grains 22a cannot be sufficiently fixed, so that the second polishing portion 22 may be easily damaged during polishing. is there.

Further, the content of the abrasive grains 22a in the second polishing section 22 is preferably larger than the content of the abrasive grains 21a in the first polishing section 21. The wear of the first polishing portion 21 and the second polishing portion 22 progresses mainly due to the spillage of the abrasive grains, and the larger the content of the abrasive grains, the easier the wear. Therefore, by making the content of the abrasive grains 22a in the second polishing section 22 larger than the content of the abrasive grains 21a in the first polishing section 21, the wear amount of the second polishing section 22 is reduced to the wear of the first polishing section 21. It can be easily controlled to be larger than the amount.

The lower limit of the difference in content between the abrasive grains 22a in the second polishing section 22 and the abrasive grains 21a in the first polishing section 21 is preferably 5% by volume, more preferably 7% by volume. On the other hand, as the upper limit of the difference in the contents, 20% by volume is preferable, and 15% by volume is more preferable. If the difference in the contents is less than the above lower limit, it becomes difficult to control the ratio of the amount of wear between the first polishing portion 21 and the second polishing portion 22, and the polishing pressure of the first polishing portion 21 is increased for polishing. The rate improvement effect may be insufficient. On the contrary, if the difference in the contents exceeds the upper limit, the content of the abrasive grains 22a in the second polishing part 22 may become too large and the second polishing part 22 may be easily damaged, or the first polishing part 21 may be damaged. The content of the abrasive grains 21a may become too small and the polishing rate may decrease.

The average particle size of the abrasive grains 22a of the second polishing unit 22 is appropriately selected from the viewpoint of controllability of the amount of wear of the second polishing unit 22. The lower limit of the average particle size of the abrasive grains 22a is preferably 1 μm, more preferably 2 μm. On the other hand, the upper limit of the average particle size of the abrasive grains 22a is preferably 20 μm, more preferably 15 μm. If the average particle size of the abrasive grains 22a is less than the above lower limit, the abrasive grains 22a are likely to spill too much, and it may be difficult to control the amount of wear of the second polishing portion 22. On the contrary, when the average particle size of the abrasive grains 22a exceeds the above upper limit, the difference between the heights of the first polishing portion 21 and the second polishing portion 22 formed at the time of polishing and the difference between the average particle diameter of the abrasive grains 22a. Becomes too small, and the abrasive grains 22a of the second polishing portion 22 come into contact with the work piece, and the ratio of contributing to grinding increases. Therefore, the polishing load is dispersed in the first polishing portion 21 and the second polishing portion 22, and the polishing pressure of the first polishing portion 21 is increased, so that the polishing rate improving effect may be insufficient.

The abrasive grains 22a of the second polishing unit 22 may be composed of one type of abrasive grains or may be composed of a plurality of types of abrasive grains.

The upper limit of the content of diamond abrasive grains in the second polishing unit 22 is preferably 0.3% by volume, more preferably 0.2% by volume. Since diamond abrasive grains are hard and have high grinding power, they are less likely to cause blinding or spillage even when they come into contact with the work piece, and are more susceptible to a large polishing load than other abrasive grains. Therefore, when the content of diamond abrasive grains in the second polishing section 22 exceeds the above upper limit, the polishing load applied to the second polishing section 22 during polishing increases. As a result, the polishing load is dispersed in the first polishing portion 21 and the second polishing portion 22, and the polishing pressure of the first polishing portion 21 is increased, so that the polishing rate improving effect may be insufficient. Further, since the polishing material 1 is mainly polished by the first polishing unit 21, the effect of improving the grinding force obtained may be insufficient with respect to the increase in the manufacturing cost of the polishing material 1. On the other hand, the lower limit of the content of the diamond abrasive grains is not particularly limited, and 0% by volume, that is, the second polishing portion 22 does not have to contain the diamond abrasive grains.

(binder)
Examples of the main component of the binder 22b of the second polishing section 22 include the same main components of the binder 21b of the first polishing section 21. Among them, polyacrylic, epoxy, polyester and polyurethane are preferable as the main components of the binder 22b of the second polishing portion 22. These resins can easily ensure good adhesion to the base material 10. Further, since these resins have a lower abrasive grain holding force than the inorganic substance, the spillage of the abrasive grains 22a progresses appropriately, and it is easy to control the amount of wear of the second polishing portion 22.

The binder 22b may appropriately contain various auxiliaries such as a dispersant, a coupling agent, a surfactant, a lubricant, a defoaming agent, a colorant, and additives, depending on the purpose.

As the lower limit of the occupied area ratio of the second polishing portion 22 in the polishing layer 20, 5% is preferable, and 15% is more preferable. On the other hand, as the upper limit of the occupied area ratio of the second polishing portion 22, 97% is preferable, and 95% is more preferable. If the occupied area ratio of the second polishing portion 22 is less than the above lower limit, the effect of suppressing damage due to the falling of the work piece into the groove 23 may be insufficient. On the contrary, when the occupied area ratio of the second polished portion 22 exceeds the above upper limit, the occupied area ratio of the first polished portion 21 is relatively small, so that the wear of the first polished portion 21 is promoted and the first The difference in height between the polishing portion 21 and the second polishing portion 22 is less likely to occur. As a result, the polishing pressure of the first polishing unit 21 cannot be sufficiently increased, and the effect of improving the polishing rate may be insufficient.

The lower limit of the occupied area ratio of the entire polished portion in the polishing layer 20 (the sum of the occupied area ratios of the first polishing portion 21 and the second polishing portion 22) is 15%, more preferably 16%, and 25%. % Is more preferable. If the occupied area ratio of the entire polished portion is less than the above lower limit, damage may occur due to the depression of the work piece into the groove or the like. On the other hand, the upper limit of the occupied area ratio of the entire polished portion is 100%. When the occupied area ratio of the entire polishing portion is 100%, the polishing layer 20 does not have a groove 23 and is composed of only the first polishing portion 21 and the second polishing portion 22.

As the lower limit of the amount of wear of the second polishing portion 22 in the Taber wear test, 0.3 g is preferable, and 0.4 g is more preferable. If the amount of wear of the second polishing portion 22 is less than the above lower limit, a difference in height due to the difference in the amount of wear between the second polishing portion 22 and the first polishing portion 21 is unlikely to occur during polishing. As a result, the polishing pressure of the first polishing unit 21 cannot be sufficiently increased, and the effect of improving the polishing rate may be insufficient. On the other hand, the upper limit of the amount of wear of the second polishing portion 22 is not particularly limited, but is usually about 0.8 g.

The lower limit of the ratio of the wear amount of the second polishing part 22 to the wear amount of the first polishing part 21 in the Taber wear test is 3, more preferably 3.5, and even more preferably 4. If the ratio of the amount of wear is less than the above lower limit, it is difficult for a step due to the difference in the amount of wear to occur between the first polishing portion 21 and the portion 21 during polishing. As a result, the polishing pressure of the first polishing unit 21 cannot be sufficiently increased, and the effect of improving the polishing rate may be insufficient. On the other hand, the upper limit of the ratio of the amount of wear is not particularly limited and is about 15.

Before the polishing material 1 is used for polishing, the surfaces of the first polishing portion 21 and the second polishing portion 22 do not have to be flush with each other as shown in FIG. A step, that is, a step having an average height of 30 μm or more and 60 μm or less may be provided in advance.

<Groove>
The grooves 23 are arranged on the surface of the polishing layer 20 in a grid pattern at equal intervals. Further, the bottom surface of the groove 23 is composed of the surface of the base material 10.

The upper limit of the average width of the groove 23 is preferably 10 mm, more preferably 8 mm. If the average width of the groove 23 exceeds the upper limit, the occupied area ratio of the convex portion 24 cannot be sufficiently secured, and the work piece tends to fall into the groove 23 during polishing, so that the work piece may be damaged. There is. On the other hand, the lower limit of the average width of the groove 23 is not particularly limited, and may be 0 mm, that is, the abrasive material 1 may have a configuration that does not have the groove 23.

[Adhesive layer]
The adhesive layer 30 is a layer for fixing the abrasive material 1 to a support for supporting the abrasive material 1 and mounting it on the polishing apparatus.

The adhesive used for the adhesive layer 30 is not particularly limited, and examples thereof include a reactive adhesive, an instant adhesive, a hot melt adhesive, and an adhesive which is a replaceable adhesive.

As the adhesive used for the adhesive layer 30, an adhesive is preferable. By using an adhesive as the adhesive used for the adhesive layer 30, the abrasive 1 can be peeled off from the support and replaced, so that the abrasive 1 and the support can be easily reused. Such adhesives are not particularly limited, but are, for example, acrylic adhesives, acrylic-rubber adhesives, natural rubber adhesives, synthetic rubber adhesives such as butyl rubber, silicone adhesives, and polyurethane adhesives. Examples include agents.

The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05 mm, more preferably 0.1 mm. The upper limit of the average thickness of the adhesive layer 30 is preferably 0.3 mm, more preferably 0.2 mm. If the average thickness of the adhesive layer 30 is less than the above lower limit, the adhesive force may be insufficient and the abrasive 1 may be peeled off from the support. On the other hand, if the average thickness of the adhesive layer 30 exceeds the above upper limit, workability may be reduced, for example, the thickness of the adhesive layer 30 may hinder the cutting of the abrasive 1 into a desired shape.

[Abrasive manufacturing method]
The polishing material 1 is formed by a step of preparing a composition for a first polishing portion, a step of preparing a composition for a second polishing portion, and printing of the first polishing portion 21 of the composition for a first polishing portion. It can be manufactured by a step of forming the second polishing portion 22 by printing a composition for the second polishing portion, and a step of laminating the adhesive layer 30 on the back surface side of the base material 10.

First, in the composition preparation step for the first polishing part, a solution in which the composition for the first polishing part (material for forming the abrasive grains 21a and the binder 21b of the first polishing part 21) is dispersed in a solvent is prepared as a coating liquid. To do. The solvent is not particularly limited as long as the material for forming the binder 21b is soluble. Specifically, methyl ethyl ketone (MEK), isophorone, terpineol, N-methylpyrrolidone, cyclohexanone, propylene carbonate and the like can be used. Diluents such as water, alcohols, ketones, acetic acid esters, and aromatic compounds may be added to control the viscosity and fluidity of the coating liquid.

Next, in the composition preparation step for the second polishing part, the composition for the second polishing part (abrasive grains 22a of the second polishing part 22 and the abrasive grains 22a) is similar to the coating liquid in the composition preparation step for the first polishing part. A solution in which the binder 22b (forming material) is dispersed in a solvent is prepared as a coating liquid. The composition preparation step for the second polishing portion may be performed before the composition preparation step for the first polishing portion or after the composition preparation step for the first polishing portion.

Next, in the first polishing portion forming step, a plurality of first polishing portions 21 are formed on the surface of the base material 10 by a printing method using the coating liquid prepared in the composition preparation step for the first polishing portion. Specifically, a mask having a shape corresponding to the inverted shape of the first polishing portion 21 is prepared, and the coating liquid is printed through the mask. As this printing method, for example, screen printing, metal mask printing, or the like can be used.

The first polishing portion 21 is formed by heat dehydration and heat curing of the printed coating liquid. Specifically, the coating liquid is dried and dehydrated by heating at room temperature (25 ° C.) and then cured by heating to form the first polishing portion 21.

Next, in the second polishing portion forming step, the second polishing portion 22 surrounding the first polishing portion 21 is formed by a printing method using the coating liquid prepared in the composition preparation step for the second polishing portion. Specifically, a mask having a shape corresponding to the inverted shape of the second polishing portion 22 is prepared, and the coating liquid is printed through the mask. As this printing method, for example, squeegee printing, bar coater printing, applicator printing and the like can be used. The second polishing portion forming step can be performed before the first polishing portion forming step or at the same time as the first polishing portion forming step.

The second polishing portion 22 is formed by heating and curing the printed coating liquid. Specifically, the coating liquid is heat-cured to form the second polishing portion 22.

Finally, in the adhesive layer laminating step, the adhesive layer 30 is laminated on the back surface side of the base material 10. Specifically, for example, a pre-formed tape-shaped adhesive layer 30 is attached to the back surface of the base material 10. The adhesive layer laminating step can also be performed before the second polishing portion forming step.

〔advantage〕
The polishing material 1 includes a first polishing portion 21 and a second polishing portion 22 surrounding the first polishing portion 21, and the second polishing portion 22 with respect to the amount of wear of the first polishing portion 21 in the Taber wear test. The ratio of the amount of wear is equal to or higher than the above lower limit. Therefore, when polishing is performed using the polishing material 1, the second polishing portion 22 surrounding the first polishing portion 21 is worn first. As a result, in a relatively short time from the start of polishing, a step is formed between the first polishing portion 21 and the second polishing portion 22 so that the second polishing portion 22 has a low height. Further, since the wear of the polished portion progresses mainly in the first polished portion 21 and the second polished portion 22 due to the spillage of the abrasive grains, the work piece is polished while maintaining this step. Therefore, since the first polishing unit 21 mainly receives the polishing load applied at the time of polishing, the polishing pressure of the first polishing unit 21 is increased, thereby increasing the grinding force of the abrasive material 1. Further, in the polishing material 1, the second polishing portion 22 surrounds the first polishing portion 21, and the occupied area ratio of the entire polishing portion in the polishing layer 20 is within the above range. Therefore, in the abrasive material 1, when the end portion of the work piece moves between the first polishing parts 21 during polishing, the second polishing part 22 can prevent the work piece from tilting toward the base material. Therefore, the abrasive material 1 can suppress damage due to the drop of the work piece into the groove 23 or the like.

[Other Embodiments]
The present invention is not limited to the above embodiment, and can be implemented in various modifications and improvements in addition to the above embodiment.

In the above embodiment, the case where the plurality of first polishing portions are regularly arranged in a block pattern has been described, but the arrangement of the plurality of first polishing portions is not limited to this. For example, the plurality of first polishing portions may be arranged at different intervals in the orthogonal X direction and the Y direction.

In the above embodiment, the grooves are formed in a grid pattern at equal intervals, but the spacing and the planar shape of the grid are not limited to the above embodiment. Further, in the above embodiment, the bottom surface of the groove is the surface of the base material, but the depth of the groove is smaller than the average thickness of the polishing layer, and the groove does not have to reach the surface of the base material.

Further, in the above embodiment, the configuration in which the groove divides the second polishing portion has been described, but the configuration of the groove is not limited to this. For example, as shown in FIG. 3, the groove 23 may be arranged between the first polishing portion 21 and the second polishing portion 22. In this case, the groove 23 may be arranged so as to surround the periphery of the first polishing portion 21, but may also be arranged so as to be in contact with a part of the first polishing portion 21.

Further, the abrasive material may have a structure having no groove.

In the above embodiment, the case where the shape formed by the outer circumference of the second polishing portion is similar to that of the first polishing portion has been described, but the shape of the second polishing portion is similar to that of the first polishing portion. Not limited. For example, as shown in FIG. 4, the first polishing portion 21 has a circular shape, and the shape formed by the outer circumference of the second polishing portion 22 may be a square shape.

In the above embodiment, the case where one second polishing portion surrounds one first polishing portion has been described, but as shown in FIG. 5, even if one second polishing portion 22 surrounds a plurality of first polishing portions 21. Good.

Further, the second polishing portion does not have to surround the entire circumference of the first polishing portion, and may have a notch in a part as shown in FIG. From the viewpoint of preventing damage due to the work piece falling into the notch or the like, the length of the portion facing the second polishing portion 22 on the entire circumference of the first polishing portion 21 is 90% or more, preferably 95% or more. Is.

In the above embodiment, the case where the polishing layer has two types of polishing portions having different amounts of wear in the Taber wear test has been described, but the polishing layer may have three or more types of polishing portions. In this case, the polishing portion having the smallest amount of wear is the first polishing portion, and the remaining two or more types of polishing portions are other polishing portions (corresponding to the second polishing portion of the above embodiment). The configuration of the other polishing portion is not particularly limited as long as the first polishing portion is surrounded by the other polishing portion. As for the configuration of the other polishing portion, for example, as shown in FIG. 7, the first polishing portion 21 is surrounded by the first other polishing portion 25, and the first other polishing portion 25 is the second other. The first other polishing portion 25 and the second other polishing portion 26 are alternately arranged along the circumference of the first polishing portion 21 as shown in FIG. Examples thereof include a configuration in which the first polishing portion 21 is surrounded in an annular shape by the entire other polishing portions arranged alternately.

Further, as shown in FIG. 9, the abrasive 2 may include a support 40 laminated via the adhesive layer 30 on the back surface side and a second adhesive layer 31 laminated on the back surface side of the support 40. .. When the abrasive material 2 includes the support 40, the abrasive material 2 can be easily handled.

Examples of the main component of the support 40 include 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 as the main component of the support 40, the support 40 has flexibility, the abrasive 2 follows the surface shape of the work piece, and the polished surface and the work piece Is easier to contact, so the polishing rate is further improved.

The average thickness of the support 40 can be, for example, 0.5 mm or more and 3 mm or less. If the average thickness of the support 40 is less than the lower limit, the strength of the abrasive 2 may be insufficient. On the other hand, when the average thickness of the support 40 exceeds the upper limit, it may be difficult to attach the support 40 to the polishing apparatus or the flexibility of the support 40 may be insufficient.

The second adhesive layer 31 can use the same adhesive as the adhesive layer 30. Further, the second adhesive layer 31 can have the same average thickness as the adhesive layer 30.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the invention is not limited to the following Examples.

[Example 1]
Diamond abrasive grains (55 mass% nickel-coated diamond, average particle size 35 μm), alumina abrasive grains (Al ₂ O ₃ , fused alumina, average particle size 12 μm), and silicate as a binder (No. 3 sodium silicate) ) Are mixed so that the content of the diamond abrasive grains in the first polishing portion is 5% by volume and the content of the alumina abrasive grains in the first polishing portion is 71% by volume, and the composition for the first polishing portion is prepared. A coating liquid was obtained.

Further, alumina abrasive grains (white alumina WA # 1000, average particle diameter 12 μm), epoxy as a binder (“TB2022” by ThreeBond Holdings Co., Ltd.), and epoxy curing agent (“TB2105C” by ThreeBond Holdings Co., Ltd.) are mixed. , The content of the alumina abrasive grains in the second polishing portion was adjusted to 85% by volume, and a coating liquid for the composition for the second polishing portion was obtained.

An aluminum plate having an average thickness of 300 μm was prepared as a base material, and a plurality of first polishing parts were formed on the surface of the base material by printing using the coating liquid of the composition for the first polishing part. The plurality of first polishing portions have a regularly arranged block pattern, and the distance between the centers of the adjacent first polishing portions is 10 mm. For printing, a mask having a pattern corresponding to the inverted shape of the first polishing portion was used. Each first polished part had an area of 9 mm ² (a square shape having a side of 3 mm in a plan view), and the average thickness of the first polished part was 500 μm. The area occupancy of the polishing layer of the first polishing portion was 9%.

The coating liquid was dried at room temperature (25 ° C.), dehydrated by heating, and then cured by heating.

Further, a rigid vinyl chloride resin plate having an average thickness of 1 mm is used as a support for supporting the base material and fixing it to the polishing apparatus, and the back surface of the base material and the front surface of the support are attached with an adhesive having an average thickness of 130 μm. I matched it. As the pressure-sensitive adhesive, double-sided tape (“# 5605HGD” manufactured by Sekisui Chemical Co., Ltd.) was used.

Next, using the coating liquid of the composition for the second polishing portion, the second polishing portion was formed by printing so as to surround the first polishing portion. Each second polished portion had an area of 81 mm ² (a square shape having an outer circumference of 9.5 mm in a plan view). The average thickness of the second polished portion was set to be the same as the average thickness of the first polished portion. The area occupancy of the second polishing portion in the polishing layer was 81%, and the area occupancy of the entire polishing portion in the polishing layer was 90%. The remaining 10% of the polishing layer was a groove, and the groove had a grid pattern with an average width of 0.5 mm.

The coating liquid was dried by heating. In this way, the abrasive of Example 1 was obtained.

[Examples 2 and 3, Comparative Example 3]
Examples 2 and 3 are the same as in Example 1 except that the occupied area ratio of the first polished portion, the occupied area ratio of the second polished portion, and the occupied area ratio of the entire polished portion are set to the values shown in Table 1. Abrasive material was obtained.

[Example 4]
Diamond abrasive grains (55 mass% nickel-coated diamond, average particle size 35 μm), alumina abrasive grains (white alumina WA # 1000, average particle size 12 μm), epoxy as a binder (“TB2022” from Three Bond Holdings Co., Ltd.), and An epoxy hardener (“TB2105C” from Three Bond Holdings Co., Ltd.) was mixed, and the content of diamond abrasive grains in the second polishing section was 0.2% by volume, and the content of alumina abrasive grains in the second polishing section was 84. The content was adjusted to 8% by volume, and a coating liquid for the composition for the second polishing portion was obtained.

The polishing material of Example 4 was obtained in the same manner as in Example 1 except that the composition for the second polishing part was used.

[Example 5]
The area occupancy of the second polishing portion in the polishing layer was 91%, and the area occupancy of the entire polishing portion in the polishing layer was 100%. The polishing material of Example 5 was obtained.

[Example 6]
Alumina abrasive grains (white alumina WA # 1000, average particle size 12 μm) and acrylic as a binder (“Dianal BR-80” from Mitsubishi Rayon Co., Ltd.) are mixed, and the content of alumina abrasive grains in the second polishing section. Was adjusted to 85% by volume, and a coating liquid for the composition for the second polishing portion was obtained.

The polishing material of Example 6 was obtained in the same manner as in Example 5 except that the composition for the second polishing part was used.

[Comparative Example 1]
Silicon carbide abrasive grains (green carbonite, average particle size 30 μm), alumina abrasive grains (white alumina WA # 1000, average particle size 12 μm), and silicate (sodium silicate No. 3) as a binder are mixed, and silicon carbide is used. The content of the abrasive grains in the second polishing portion was adjusted to 30% by volume, and the content of the alumina abrasive grains in the second polishing portion was adjusted to 46% by volume to obtain a coating liquid for the composition for the second polishing portion. It was.

The abrasive material of Comparative Example 1 was obtained in the same manner as in Example 5 except that the composition for the second polishing portion was used.

[Comparative Example 2]
Diamond abrasive grains (55 mass% nickel-coated diamond, average particle size 35 μm), alumina abrasive grains (white alumina WA # 1000, average particle size 12 μm), and silicate (sodium No. 3 silicate) as a binder are mixed. , The content of the silicon carbide abrasive grains in the second polishing portion is 2.5% by volume, and the content of the alumina abrasive grains in the second polishing portion is 77.5% by volume. I got the coating liquid of the thing.

An abrasive material of Comparative Example 2 was obtained in the same manner as in Example 1 except that the composition for the second polishing portion was used.

[Polishing conditions]
The sapphire substrate was polished using the abrasives obtained in Examples 1 to 6 and Comparative Examples 1 to 3. As the sapphire substrate, a c-plane sapphire substrate having a diameter of 5.08 cm and a specific gravity of 3.97 was used. A known double-sided polishing machine was used for the above polishing. The carrier of the double-sided grinding machine is epoxy glass with a thickness of 0.4 mm. Polishing was performed under the conditions that the polishing pressure was 200 g / cm ² , the upper surface plate rotation speed was 25 rpm, the lower surface plate rotation speed was 50 rpm, and the SUN gear rotation speed was 8 rpm. At that time, 30 cc of "Daphne Cut GS50K" manufactured by Idemitsu Kosan Co., Ltd. was supplied as coolant.

[Evaluation method]
With respect to the abrasives of Examples 1 to 6 and Comparative Examples 1 to 3, the amount of wear was measured by the Taber wear test, and the first and second polishing portions when the sapphire substrate was polished using these abrasives. The average height of the steps and the polishing rate were measured. The results are shown in Table 1.

<Measurement of wear amount>
For the measurement of the amount of wear by the Taber wear test, two abrasives of Examples 1 to 6 and two of Comparative Examples 1 to 3 were prepared. Of these two abrasives, the second abrasive is removed from one abrasive to make only the first abrasive, and the first abrasive is removed from the other abrasive to make the second abrasive. Only as an abrasive. Test pieces (average diameter 104 mm, average thickness 300 μm) were prepared from each of the above two abrasives, and each test piece was used with a Taber wear tester (“MODEL174” manufactured by Taber Instrument) to wear the wheel H-18 and load. It was worn by 320 rotations under the condition of 4.9 N (500 gf). The mass difference [g] of the test piece before and after 320 rotations was measured and used as the amount of wear [g].

<Measurement of average height of steps>
The average height of the step between the first polishing part and the second polishing part was obtained by measuring any 15 points using a laser displacement meter (manufactured by Keyence Co., Ltd.) and as the average value of the obtained measured values. ..

<Polishing rate>
Regarding the polishing rate, the sapphire substrate is polished for 10 minutes, and the weight change (g) of the substrate before ^{and after polishing is divided by the surface area of the substrate (cm 2} ), the specific gravity of the substrate (g / cm ³ ), and the polishing time (minutes). Then, the unit was converted to μm / min and calculated.

In Table 1, "-" of the curing agent and the second abrasive grains means that the curing agent and the second abrasive grains are not used, respectively. Further, "-" of the average height of the step and the polishing rate means that the substrate could not be measured because the substrate was damaged due to the drop into the groove of the substrate.

From the results in Table 1, the abrasives of Examples 1 to 6 have a higher polishing rate than the abrasives of Comparative Examples 1 to 3. On the other hand, in the abrasives of Comparative Examples 1 and 2, the ratio of the amount of wear in the taber wear test of the first polishing part to the second polishing part is less than 3, so that the first polishing part and the second polishing part are polished at the time of polishing. There is not enough step between the parts. Therefore, in the polishing using the abrasives of Comparative Examples 1 and 2, the polishing load was dispersed in the first polishing portion and the second polishing portion, so that the polishing pressure of the first polishing portion did not increase and the polishing rate was low. Conceivable. Further, since the area occupancy of the entire polished portion of the abrasive material of Comparative Example 3 is less than 15%, it is considered that the abrasive material is damaged due to the drop into the groove of the work piece.

From the above, the ratio of the amount of wear of the second polishing part to the Taber wear test of the first polishing part is set to 3 or more, and the occupied area ratio of the entire polishing part in the polishing layer is set to 15% or more and 100% or less. It can be seen that high processing efficiency can be achieved while suppressing damage due to the work piece falling into the groove or the like.

The abrasive material of the present invention can achieve relatively high processing efficiency while suppressing damage due to a drop of the work piece into a groove or the like. Therefore, the abrasive is suitably used for surface polishing of a substrate such as glass or sapphire.

1, 2 Abrasive 10 Base material 20 Polishing layer 21 First polishing part 22 Second polishing part 21a, 22a Abrasive grains 21b, 22b Binder 23 Groove 24 Convex part 25, 26 Other polishing part 30 Adhesive layer 31 Second adhesion Layer 40 support

Claims (4)

An abrasive material comprising a base material and a polishing layer laminated on the surface side of the base material.
The polishing layer contains a plurality of types of polishing portions containing abrasive grains and a binder thereof and having different amounts of wear in the Taber wear test.
The first polishing portion having the smallest amount of wear among the plurality of types of polishing portions is surrounded by the other polishing portions.
The ratio of the wear amount of the other polishing part to the wear amount of the first polishing part is 3 or more.
The occupied area ratio of the entire polished portion in the polishing layer is 15% or more and 100% or less.
The occupied area ratio of the first polishing portion in the polishing layer is 3% or more and 16% or less.
A polishing material, wherein the polishing layer has a plurality of first polishing portions, and the plurality of first polishing portions are arranged in a regular block pattern. The abrasive according to claim 1, wherein the abrasive grains of the first polishing portion are composed of a plurality of types of abrasive grains. The first polishing part contains diamond abrasive grains,
The abrasive according to claim 2, wherein the content of the diamond abrasive grains in the first polishing portion is 1% by volume or more and 20% by volume or less. The abrasive according to claim 3 , wherein the content of the diamond abrasive grains in the other polishing portion is 0.3% by volume or less.

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