JPWO2019123922A1 - Abrasive and method for producing abrasive - Google Patents

Abstract

SUMMARY OF THE INVENTION It is an object of the present invention to provide an abrasive and a method of manufacturing an abrasive capable of increasing the thickness of a polished portion while suppressing a decrease in a polishing rate. The abrasive of the present invention is an abrasive comprising a base material and a polishing layer laminated on the surface side of the base material and containing abrasive grains and a binder, wherein the polishing layer has a plurality of columnar polishing parts. The polishing portion contains fumed silica, and the base material mainly contains a heat-resistant resin.

Description

  The present invention relates to an abrasive and a method for producing the abrasive.

  For example, in the processing of a glass substrate used for an electronic device such as a hard disk, an abrasive of fixed abrasive is generally used. As such an abrasive, an abrasive formed by laminating a polishing layer containing abrasive grains and a binder on the surface of a base material is known.

  In the fixed abrasive, the polishing layer is composed of a plurality of polishing portions. By configuring the polishing layer with a plurality of polishing portions in this manner, the occupancy of the area in contact with the workpiece is reduced, and the surface pressure during polishing is increased, so that a high polishing rate can be achieved. Further, since grinding dust can be eliminated by the grooves formed between the plurality of polishing portions, a decrease in the polishing rate due to clogging of the polishing material can be suppressed.

  With such an abrasive, the polishing layer gradually wears with the processing of the glass substrate. Therefore, in order to extend the life of the abrasive, it is necessary to increase the thickness of the polishing portion. The polishing layer is generally formed using a printing method. In the case of using the printing method, when the polished portion is thickened, the aspect ratio is increased, so that dripping is likely to occur during printing, and it is difficult to form each polished portion in a columnar shape. For this reason, in a conventional polishing material having a thick polishing portion, a cone-shaped polishing portion or a polishing portion having a large top surface area is used (see, for example, JP-A-2014-18893).

  However, when the polishing portion is formed in a conical shape, the area of the top surface of the polishing portion increases as the polishing layer wears, so that the surface pressure during polishing decreases and the polishing rate may decrease. When the area of the polishing section is increased, it is necessary to increase the width of the groove between the polishing sections in order to reduce the area occupancy. When the width of the groove is widened, the workpiece easily falls into the groove, and thus the workpiece may be flawed. For this reason, when increasing the area of the polishing portion, it is difficult to reduce the area occupancy, so that the surface pressure during polishing decreases, and the polishing rate may decrease.

JP 2014-18893 A

  The present invention has been made in view of such inconvenience, and an object of the present invention is to provide an abrasive and a method for manufacturing an abrasive capable of increasing the thickness of a polished portion while suppressing a decrease in a polishing rate.

  The present inventors have conducted intensive studies on a method of manufacturing an abrasive material capable of forming individual polished portions in a columnar shape even when the polished portions are thick, and by including fumed silica in the polished portions, the polishing layer is printed by Attention was paid to the fact that dripping during formation is suppressed, and individual polished portions are easily formed in a columnar shape. When the polished portion contains fumed silica, the adhesion between the substrate and the polished portion may be reduced, and the polished portion may be easily peeled off. The present inventors have found that the easiness of peeling between the base material and the polished portion can be solved by using a base material mainly composed of a heat-resistant resin as the base material, and completed the present invention.

  That is, the invention made to solve the above-mentioned problem is an abrasive material comprising a base material and a polishing layer laminated on the surface side of the base material and containing abrasive grains and a binder, wherein the polishing layer has a plurality of polishing layers. The above-mentioned polishing part contains fumed silica, and the above-mentioned base material has a heat resistant resin as a main component.

  Since the polishing portion of the abrasive contains fumed silica, the polishing portion can be formed in a columnar shape even if the polishing portion is thick. For this reason, the polishing material does not need to have a polished portion in the shape of a cone or to increase the area of the top surface of the polished portion. Therefore, even if the polishing layer is worn, the polishing rate does not easily decrease. In addition, since the base material of the abrasive is a heat-resistant resin as a main component, it is possible to suppress a decrease in adhesion between the base material and the polishing part due to the polishing part containing fumed silica. For this reason, in the abrasive material, the base material and the polished portion are not easily separated. Therefore, the polishing material can make the polishing portion thicker while suppressing a reduction in the polishing rate.

  The content of the fumed silica in the polishing section is preferably from 0.1% by volume to 20% by volume. By setting the content of the fumed silica in the polishing portion within the above range, it is possible to stably form the columnar polishing portion while suppressing a decrease in adhesion due to the inclusion of the fumed silica during the production of the abrasive. Therefore, a more stable polishing rate can be developed.

  The average thickness of the polishing portion is preferably 300 μm or more and 5000 μm or less. By setting the average thickness of the polishing portion within the above range, the effect of exhibiting a stable polishing rate due to the inclusion of fumed silica in the polishing portion is easily exerted.

  The base material is preferably polycarbonate or biaxially stretched polyethylene terephthalate. When the base material is made of polycarbonate or biaxially stretched polyethylene terephthalate, the adhesion between the base material and the polished portion is enhanced, and the base material and the polished portion can be made harder to peel off.

  Another invention made in order to solve the above-mentioned problem is a method for producing an abrasive material comprising a base material and a polishing layer laminated on the surface side of the base material and containing abrasive grains and a binder, wherein the polishing layer Forming the polishing layer by printing a composition for polishing, the polishing layer has a plurality of columnar polishing portions, the composition for polishing layer contains fumed silica, the base material is a heat-resistant resin As a main component.

  In the method for producing an abrasive, since the composition for the polishing layer contains fumed silica, the fumed silica imparts thixotropy to the composition for the polishing layer when forming the polishing layer by printing, and prevents dripping. it can. For this reason, by using the method for manufacturing an abrasive, a columnar polishing portion can be formed even in a thick polishing portion. In addition, in the method for producing an abrasive, since the base material contains a heat-resistant resin as a main component, even when the polishing layer composition contains fumed silica, the base material and the polished portion are not easily separated. Therefore, by using the method for manufacturing an abrasive, it is possible to manufacture an abrasive having a thick polished portion while suppressing a decrease in the polishing rate.

  Here, the "main component" means a component having the largest content, preferably a component having a content of 50% by mass or more, more preferably 90% by mass or more.

  As described above, the polishing material of the present invention and the polishing material manufactured by the method of manufacturing the polishing material of the present invention can make the polishing portion thicker while suppressing a decrease in the polishing rate. Therefore, the abrasive of the present invention and the abrasive manufactured by the method of manufacturing an abrasive of the present invention can have a long life while exhibiting a stable polishing rate.

FIG. 1 is a schematic partial plan view showing an abrasive according to an embodiment of the present invention. FIG. 2 is a schematic partial cross-sectional view taken along line AA of FIG. 1. It is a flow figure showing a manufacturing method of an abrasive concerning one embodiment of the present invention. FIG. 3 is a schematic partial cross-sectional view illustrating an abrasive according to an embodiment different from FIG. 2.

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

[Abrasive]
The abrasive 1 shown in FIGS. 1 and 2 includes a substrate 10, a polishing layer 20 laminated on the front side of the substrate 10, and an adhesive layer 30 laminated on the back side of the substrate 10. The polishing layer 20 has a plurality of polishing portions 20a and grooves 20b provided between the polishing portions 20a.

  The polishing material 1 is suitably used as a fixed abrasive polishing material for polishing the surface of a glass material, particularly for polishing the surface of an aluminosilicate glass substrate used for a cover glass, a hard disk or the like.

<Substrate>
The base material 10 is a plate-shaped or sheet-shaped member for supporting the polishing layer 20.

  The base material 10 contains a heat-resistant resin as a main component. Examples of such a heat-resistant resin include polycarbonate, biaxially stretched polyethylene terephthalate, polyimide, and polyamide. Among them, polycarbonate and biaxially stretched polyethylene terephthalate are preferred, and polycarbonate is more preferred. When the base material 10 is made of polycarbonate or biaxially stretched polyethylene terephthalate, the adhesion between the base material 10 and the polishing part 20a is increased, and the base material 10 and the polishing part 20a can be hardly peeled off.

  As a minimum of glass transition temperature of substrate 10, 60 ° C is preferred, 80 ° C is more preferred, and 100 ° C is still more preferred. When the glass transition temperature of the base material 10 is lower than the lower limit, heat resistance is insufficient, and the base material 10 is easily deformed by heat when forming the polishing part 20a. For this reason, there is a possibility that the adhesion between the base material 10 and the polishing portion 20a may be reduced. On the other hand, the upper limit of the glass transition temperature of the substrate 10 is not particularly limited. For example, the glass transition temperature of the substrate 10 is set to 500 ° C. or less.

  Further, the base material 10 preferably has flexibility. Since the base material 10 has flexibility as described above, the abrasive 1 follows the surface shape of the work, and the contact area between the polished surface and the work is increased, so that the polishing rate can be increased. .

  In addition, the surface of the base material 10 may be subjected to a treatment for enhancing adhesiveness such as a chemical treatment, a corona treatment, and a primer treatment.

  The shape and size of the base material 10 are not particularly limited, but are, for example, a square shape having a side of 140 mm or more and 160 mm or less, a disc shape having a diameter of 200 mm or more and 2022 mm or less, a circle having an outer diameter of 200 mm or more and 2022 mm or less and an inner diameter of 100 mm or more and 658 mm or less. It can be annular or the like. Further, a configuration in which a plurality of base materials 10 juxtaposed on a plane are supported by a single support may be employed.

  As a minimum of average thickness of substrate 10, 70 micrometers is preferred, 300 micrometers is more preferred, and 500 micrometers is still more preferred. On the other hand, as a maximum of average thickness of substrate 10, 3000 micrometers is preferred and 2000 micrometers is more preferred. If the average thickness of the base material 10 is less than the above lower limit, the warp of the base material 10 may easily occur when the polishing portion 20a is thick. Conversely, when the average thickness of the base material 10 exceeds the above upper limit, the base material 10 becomes difficult to follow the surface shape of the workpiece, and the polishing rate may be reduced.

<Polishing layer>
The polishing layer 20 includes abrasive grains 21, a binder 22, and a fumed silica 23 in a polishing section 20a. The polishing section 20a includes a filler (not shown).

(Abrasive grains)
Examples of the abrasive grains 21 include diamond abrasive grains, alumina abrasive grains, silica abrasive grains, ceria abrasive grains, and silicon carbide abrasive grains. Among them, diamond abrasive grains which are harder than other abrasive grains are preferable. By using the diamond grains as the abrasive grains 21, the polishing power is improved, and the polishing rate can be further improved.

  The diamond of the diamond abrasive grains may be a single crystal or polycrystal, or may be a diamond that has been subjected to a treatment such as Ni coating. Among them, single crystal diamond and polycrystalline diamond are preferred. Single crystal diamond is harder than other diamonds and has higher grinding power. In addition, polycrystalline diamond is easily cleaved in units of microcrystals constituting the polycrystal and is less likely to be blinded. Therefore, even if polishing is performed for a long period of time, a reduction in polishing rate is small.

  The average particle diameter of the abrasive grains 21 is appropriately selected from the viewpoint of the polishing rate and the surface roughness of the workpiece after polishing. As a minimum of average particle diameter of abrasive grain 21, 2 micrometers is preferred, 10 micrometers is more preferred, and 15 micrometers is still more preferred. On the other hand, the upper limit of the average particle diameter of the abrasive grains 21 is preferably 150 μm, more preferably 125 μm, and still more preferably 100 μm. If the average particle size of the abrasive grains 21 is less than the above lower limit, the polishing power of the abrasive 1 may be insufficient, and the polishing rate may be reduced. Conversely, if the average particle diameter of the abrasive grains 21 exceeds the above upper limit, polishing accuracy may be reduced. Here, 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.

  The lower limit of the content of the abrasive grains 21 in the polishing section 20a is preferably 0.5% by volume, more preferably 2% by volume, and still more preferably 4% by volume. On the other hand, the upper limit of the content of the abrasive grains 21 is preferably 55% by volume, more preferably 45% by volume, and still more preferably 35% by volume. When the content of the abrasive grains 21 is less than the lower limit, the polishing force of the polishing layer 20 may be insufficient. Conversely, if the content of the abrasive grains 21 exceeds the upper limit, the polishing layer 20 may not be able to hold the abrasive grains 21.

(binder)
The main component of the binder 22 is not particularly limited, but includes a resin or an inorganic substance. Above all, a resin is preferred from the viewpoint of adhesion to the substrate 10.

  Examples of the resin include resins such as polyurethane, polyphenol, epoxy, polyester, cellulose, ethylene copolymer, polyvinyl acetal, polyacrylic acid and salts thereof, polyacrylate, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, and polyamide. Can be mentioned. Among them, preferred are polyacrylates, epoxies, polyesters, and polyurethanes, which easily ensure good adhesion to a substrate. The resin may be at least partially crosslinked.

  Examples of the inorganic substance include silicates, phosphates, and polyvalent metal alkoxides. Among them, a silicate having a high abrasive grain holding power is preferable. Examples of such silicates include sodium silicate and potassium silicate.

  The binder 22 may appropriately contain various assistants and additives such as a dispersant, a coupling agent, a surfactant, a lubricant, an antifoaming agent, and a coloring agent according to the purpose.

(Fumed silica)
The fumed silica 23 is a kind of dry silica and is a fine particle (powder). Its composition is amorphous silica or high purity glass.

  The lower limit of the average primary particle diameter of the fumed silica 23 is preferably 5 nm, more preferably 7 nm. On the other hand, the upper limit of the average primary particle diameter of the fumed silica 23 is preferably 100 nm, more preferably 60 nm, and still more preferably 40 nm. If the average primary particle diameter of the fumed silica 23 is less than the above lower limit, the fumed silica 23 tends to flutter, and handling of the abrasive 1 during manufacture may be difficult. Conversely, if the average primary particle size of the fumed silica 23 exceeds the upper limit, the thixotropy of the fumed silica 23 at the time of manufacturing the abrasive 1 may be insufficient, and the polishing portion 20a may not be columnar.

  The lower limit of the content of the fumed silica 23 in the polishing section 20a is preferably 0.1% by volume, more preferably 1% by volume. On the other hand, the upper limit of the content of the fumed silica 23 is preferably 20% by volume, more preferably 10% by volume, and still more preferably 8% by volume. If the content of the fumed silica 23 is less than the above lower limit, the thixotropy of the fumed silica 23 during the production of the abrasive 1 may be insufficient, and the polishing portion 20a may not be columnar. Conversely, when the content of the fumed silica 23 exceeds the above upper limit, abrasion of the polishing portion 20a is likely to proceed, and the life of the abrasive 1 may be reduced, or the adhesion between the base material 10 and the polishing portion 20a may be reduced. It may decrease.

(filler)
Examples of the filler include oxides such as alumina, silica, cerium oxide, magnesium oxide, zirconia, and titanium oxide, and composite oxides such as silica-alumina, silica-zirconia, and silica-magnesia. These may be used alone or in combination of two or more as necessary. Among them, alumina capable of obtaining high polishing power is preferable.

  Although the average particle size of the filler also depends on the average particle size of the abrasive grains 21, the lower limit of the average particle size of the filler is preferably 0.01 μm, more preferably 2 μm. On the other hand, the upper limit of the average particle diameter of the filler is preferably 40 μm, more preferably 20 μm, and still more preferably 15 μm. If the average particle size of the filler is less than the lower limit, the polishing rate may be reduced due to the insufficient effect of the filler on improving the elastic modulus of the binder 22. On the other hand, when the average particle diameter of the filler exceeds the upper limit, the filler may hinder the polishing power 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 diameter of the filler to the average particle diameter of the abrasive grains 21 is preferably 0.01, more preferably 0.05, and still more preferably 0.1. On the other hand, the upper limit of the ratio of the average particle diameter of the filler to the average particle diameter 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 polishing rate may decrease due to the insufficient effect of the filler to improve the elastic modulus of the binder 22. Conversely, if the ratio of the average particle size of the filler to the average particle size of the abrasive grains 21 exceeds the upper limit, the filler may hinder the polishing power of the abrasive grains 21.

  Although the content of the filler in the polishing portion 20a depends on the content of the abrasive grains 21, the lower limit of the content of the filler in the polishing portion 20a is preferably 15% by volume, and more preferably 30% by volume. preferable. On the other hand, the upper limit of the content of the filler is preferably 75% by volume, and more preferably 72% by volume. If the content of the filler is less than the lower limit, the polishing rate may be reduced due to the lack of the effect of the filler on improving the elastic modulus of the binder 22. Conversely, when the content of the filler exceeds the upper limit, the filler may hinder the polishing power of the abrasive grains 21.

(Polishing unit)
The polishing part 20a is columnar. That is, the area of the bottom surface of the polishing portion 20a is 0.9 times or more and 1.5 times or less, preferably 0.93 times or more and 1.2 times or less, more preferably 0.95 times or more of the area of the top surface of the polishing portion 20a. It is not less than twice and not more than 1.05 times.

  The plurality of polishing units 20a are in the form of a block pattern regularly arranged in the same shape. The shape of the top surface of the polishing portion 20a is not particularly limited, but may be a square shape as shown in FIG. 1, a circular shape, a polygonal shape, or the like.

The lower limit of the average area of the top surface of the polishing unit 20a, preferably 1 mm ^2, 2 mm ² is more preferable. In contrast, the upper limit of the average area of the top surface of the polishing unit 20a, preferably 150 mm ^2, 130 mm ² and more preferably. If the average area of the top surface of the polishing section 20a is less than the above lower limit, the polishing section 20a may peel off from the base material 10. Conversely, if the average area of the top surface of the polishing portion 20a exceeds the above upper limit, the contact area of the polishing layer 20 with the workpiece during polishing increases, and the polishing rate may decrease due to frictional resistance.

  The lower limit of the area occupation ratio of the plurality of polishing portions 20a to the entire polishing layer 20 is preferably 5%, more preferably 10%. On the other hand, the upper limit of the area occupancy of the polishing section 20a is preferably 60%, and more preferably 55%. If the area occupancy of the polishing section 20a is less than the lower limit, the pressure applied during polishing is too concentrated on the narrow polishing section 20a, and the polishing section 20a may be separated from the base material 10. Conversely, if the area occupancy of the polishing section 20a exceeds the upper limit, the polishing layer 20 has a large contact area with the workpiece during polishing, and the polishing rate may decrease due to frictional resistance. The “area of the entire polishing layer” is a concept including the area of the groove of the polishing layer.

  The lower limit of the average thickness of the polishing section 20a is preferably 300 μm, more preferably 500 μm. On the other hand, the upper limit of the average thickness of the polishing portion 20a is preferably 5000 μm, and more preferably 3000 μm. When the average thickness of the polished portion 20a is less than the lower limit, the life may be insufficient, or the shape stabilizing effect of the polished portion 20a at the time of manufacturing due to the inclusion of the fumed silica 23 in the polished portion 20a may not be sufficiently exhibited. There is. Conversely, if the average thickness of the polishing portion 20a exceeds the above upper limit, the polishing portion 20a may not be columnar.

(groove)
The bottom surface of the groove 20b is constituted by the surface of the base material 10.

  The average width of the groove 20b is determined by the area of the top surface and the area occupancy of the polishing portion 20a, and the lower limit of the average width of the groove 20b is preferably 0.3 mm, more preferably 0.5 mm. On the other hand, the upper limit of the average width of the groove 20b is preferably 10 mm, more preferably 8 mm. If the average width of the groove 20b is less than the above lower limit, polishing powder generated by polishing may clog the groove 20b. Conversely, if the average width of the groove 20b exceeds the above upper limit, the workpiece tends to fall into the groove 20b during polishing, so that the workpiece may be damaged.

<Adhesive layer>
The adhesive layer 30 is a layer that fixes the abrasive 1 to a support for supporting the abrasive 1 and mounting the abrasive 1 in a 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 a pressure-sensitive adhesive that is a replaceable adhesive.

  The adhesive used for the adhesive layer 30 is preferably an adhesive. 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. Examples of such an adhesive include, but are not particularly limited to, an acrylic adhesive, an acrylic-rubber adhesive, a natural rubber adhesive, a synthetic rubber adhesive such as butyl rubber, a silicone adhesive, and a polyurethane adhesive. Agents and the like.

  The lower limit of the average thickness of the adhesive layer 30 is preferably 0.05 mm, more preferably 0.1 mm. On the other hand, 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 strength may be insufficient, and the abrasive 1 may be separated from the support. Conversely, when the average thickness of the adhesive layer 30 exceeds the upper limit, the 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. .

<Advantages>
Since the polishing portion 20a of the polishing material 1 includes the fumed silica 23, the polishing portion 20a can be formed in a columnar shape even if the polishing portion 20a is thick. For this reason, the polishing material 1 does not require the polishing portion 20a to have a conical shape or increase the area of the top surface of the polishing portion 20a, so that the polishing rate is reduced even if the polishing layer 20 is worn. hard. Further, in the polishing material 1, since the base material 10 is mainly composed of a heat-resistant resin, it is possible to suppress a decrease in adhesion between the base material 10 and the polishing part 20a due to the polishing part 20a including the fumed silica 23. . For this reason, the base material 10 and the polishing portion 20a of the polishing material 1 are not easily separated. Therefore, the polishing material 1 can make the polishing portion 20a thicker while suppressing a reduction in the polishing rate.

[Abrasive manufacturing method]
3 mainly includes a preparation step S1, a polishing layer forming step S2, and an adhesive layer attaching step S3. By using the method for manufacturing an abrasive material, for example, polishing including the base material 10 shown in FIGS. 1 and 2 and the polishing layer 20 laminated on the surface side of the base material 10 and including the abrasive grains 21 and the binder 22 is performed. Material 1 can be manufactured.

<Preparation process>
In the preparation step S1, a composition for a polishing layer containing abrasive grains 21, a binder 22, and a fumed silica 23 is prepared.

  Specifically, a composition for a polishing layer including the forming materials of the abrasive grains 21, the fumed silica 23, and the binder 22 is prepared as a coating liquid. Since the contents of the abrasive grains 21 and the fumed silica 23 in the solid content are the contents of the abrasive grains 21 and the fumed silica 23 of the polishing unit 20a after the production, respectively, the content in the polishing unit 20a is desired. The amount of the solid content is appropriately determined so as to obtain the value of

  Further, a diluent such as water or alcohol is added to control the viscosity and fluidity of the coating liquid. By this dilution, a part of the abrasive grains 21 included in the polishing section 20a can be projected from the surface of the binder 22. That is, by adding the diluent, the thickness of the binder 22 decreases when the polishing layer composition is dried in the polishing layer forming step S2, and the protrusion amount of the abrasive grains 21 can be increased. Therefore, a high polishing rate can be developed from the beginning of polishing by this dilution.

<Polishing layer forming step>
In the polishing layer forming step S2, the polishing layer 20 is formed by printing the polishing layer composition prepared in the preparation step S1. The polishing layer forming step S2 includes a coating step and a drying step.

(Coating process)
In the coating step, the polishing layer composition is coated on the surface of the substrate 10. As the base material 10, a material having a heat-resistant resin as a main component is used.

  Specifically, using the coating liquid prepared in the preparation step S1, the polishing layer 20 having a plurality of polishing portions 20a and grooves 20b provided between the polishing portions 20a is formed on the surface of the base material 10 by a printing method. Form. In order to form the groove 20b, a mask having a shape corresponding to the shape of the groove 20b 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.

  As the printing mask, a SUS or fluororesin mask is preferable. Since the mask made of SUS or fluororesin can be made thicker, the polished portion 20a having a large average thickness can be easily manufactured.

  The thickness of the polishing section 20a can be adjusted mainly by the thickness of the mask and the coating amount. Therefore, in this coating step, the coating amount of the composition for a polishing layer may be adjusted so that the average thickness of the polishing portion 20a is 300 μm or more, more preferably 500 μm or more. By adjusting the coating amount so that the average thickness of the polishing portion 20a is not less than the above lower limit, the life of the polishing material 1 can be improved. On the other hand, the upper limit of the average thickness of the polishing section 20a adjusted in the coating step is not particularly limited, but is preferably 5000 μm, more preferably 3000 μm, from the viewpoint of manufacturing cost.

(Drying process)
In the drying step, the coating liquid (composition for the polishing layer) after the above-mentioned coating step is heated and dried. The coating liquid is cured by the heating and drying, and the polishing layer 20 is formed.

  This drying step is performed after removing the mask. In the method for producing an abrasive, since the composition for the polishing layer contains fumed silica 23, the fumed silica 23 imparts thixotropic properties to the composition for the polishing layer. Therefore, the viscosity of the polishing layer composition during heating is appropriately controlled, and dripping can be suppressed. Therefore, even when the polishing portion 20a is thick, the columnar polishing portion 20a can be formed.

  The lower limit of the heating temperature in the drying step is preferably 80 ° C, more preferably 100 ° C. On the other hand, the upper limit of the heating temperature is preferably 300 ° C, more preferably 200 ° C. When the heating temperature is lower than the lower limit, the composition for the polishing layer is not sufficiently cured, the amount of wear increases, and the life of the polishing material 1 may be shortened. Conversely, if the heating temperature exceeds the upper limit, the polishing section 20a may be deteriorated by heat.

  The heating time in the drying step depends on the heating temperature, but the lower limit of the heating time is preferably 2 hours, more preferably 2.5 hours. On the other hand, the upper limit of the heating time is preferably 40 hours, more preferably 32 hours, and even more preferably 20 hours. If the heating time is shorter than the lower limit, the polishing layer composition may not be sufficiently cured, the amount of wear may increase, and the life of the abrasive 1 may be shortened. Conversely, if the heating time exceeds the upper limit, the production efficiency may decrease.

<Adhesive layer sticking process>
In the adhesive layer attaching step S3, the adhesive layer 30 is laminated on the back surface side of the base material 10. Specifically, for example, a tape-shaped adhesive layer 30 formed in advance is attached to the back surface of the base material 10.

<Advantages>
In the method for manufacturing an abrasive, the composition for the polishing layer contains fumed silica 23, so that when forming the polishing layer 20 by printing, the fumed silica 23 imparts thixotropic properties to the composition for the polishing layer. Who can be deterred. For this reason, by using the method for manufacturing the abrasive, the pillar-shaped polishing portion 20a can be formed even with the thick polishing portion 20a. In addition, in the method for manufacturing an abrasive, since the base material 10 is mainly composed of a heat-resistant resin, even when the polishing layer composition contains fumed silica 23, the base material 10 and the polishing portion 20a are in contact with each other. It is hard to come off. Therefore, by using the method for manufacturing an abrasive, it is possible to manufacture an abrasive having a thicker polishing portion 20a while suppressing a decrease in the polishing rate.

[Other Embodiments]
The present invention is not limited to the above-described embodiment, and can be embodied with various changes and improvements in addition to the above-described aspects.

  In the above embodiment, the case where the polishing unit has a block pattern shape has been described, but the polishing unit is not limited to the block pattern shape. That is, the plurality of polishing units may have different shapes or may be irregularly arranged. However, from the viewpoint of reducing polishing anisotropy, it is preferable that the polished portion has a block pattern.

  In the above embodiment, the case where the polishing portion contains a filler has been described. However, the filler is not an essential constituent element, and an abrasive having a polishing portion containing no filler is also intended by the present invention.

  In the above embodiment, the case where the abrasive has the adhesive layer has been described, but the adhesive layer is not an essential component and can be omitted. When the abrasive does not have an adhesive layer, the adhesive layer attaching step of the method for producing an abrasive is omitted.

  Alternatively, as shown in FIG. 4, the abrasive 2 may include a support 40 laminated via the adhesive layer 30 on the back surface and a second adhesive layer 31 laminated on the back surface of the support 40. . The provision of the support 40 in the abrasive 2 facilitates handling of the abrasive 2.

  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 a main component of the support body 40, the support body 40 has flexibility, the abrasive 2 follows the surface shape of the work, and the polishing surface and the work Are more likely to come into contact with each other, so that 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, the support 40 may be difficult to be attached to a polishing apparatus, and the flexibility of the support 40 may be insufficient.

  The same adhesive as the adhesive layer 30 can be used for the second adhesive layer 31. 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 present invention is not limited to the following Examples.

[Example 1]
Diamond abrasive grains (“SCMD-C12-22” from Sino Crystal Diamond, average particle diameter 16 μm), alumina as filler (Al ₂ O ₃ , “LA4000” from Taiheiyo Random Corporation, average particle diameter 4 μm), fume Dosilica (“Aerosil 200” from Aerosil) and epoxy resin (“JER828” from Mitsubishi Chemical Corporation) as a binder are mixed, the content of diamond abrasive grains in the solid content is 3% by volume, and the content of filler The amount was adjusted to 71% by volume and the content of fumed silica was 5% by volume to obtain a coating liquid.

A base material (average thickness: 300 μm) mainly composed of polycarbonate as a heat-resistant resin was prepared as a base material, and was coated on the surface of the base material by printing using the above-mentioned coating solution. As a printing pattern, a fluororesin mask having a circular opening having a diameter of 6 mm (average area 28.27 mm ² ) in plan view at an area occupation ratio of 44% and an average thickness of 1000 μm was used. The opening has a block pattern. The coating amount was adjusted so that the average thickness of the polished portion was 1000 μm. The coating liquid was cured by drying at 120 ° C. for 16 hours in an oven.

  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 to the polishing apparatus, and between the back surface of the base material and the front surface of the support, and the back surface of the support. An adhesive having an average thickness of 130 μm was attached to a polishing machine platen to be described later. As the pressure-sensitive adhesive, a double-sided tape (“# 5605HGD” manufactured by Sekisui Chemical Co., Ltd.) was used.

  Thus, the abrasive of Example 1 was obtained.

[Example 2]
An abrasive of Example 2 was obtained in the same manner as in Example 1, except that the amount of coating was adjusted so that the average thickness of the polished portion was 300 μm.

[Example 3]
A polishing material of Example 3 was obtained in the same manner as in Example 1, except that a base material (average thickness: 75 μm) containing biaxially oriented polyethylene terephthalate as a heat-resistant resin as a main component was prepared.

[Comparative Example 1]
Except that the coating liquid of Example 1 did not contain fumed silica and was adjusted so that the content of diamond abrasive grains in the solid content was 3% by volume and the content of filler was 76% by volume. In the same manner as in Example 1, an abrasive of Comparative Example 1 was obtained.

[Comparative Example 2]
A polishing material of Comparative Example 2 was obtained in the same manner as in Comparative Example 1, except that a base material (average thickness: 300 μm) containing biaxially stretched polyethylene terephthalate as a main component was prepared.

[Comparative Example 3]
An abrasive of Comparative Example 3 was obtained in the same manner as in Comparative Example 1, except that an aluminum plate (average thickness 300 μm) was prepared as a substrate.

[Comparative Example 4]
An abrasive of Comparative Example 4 was obtained in the same manner as in Example 1 except that an aluminum plate (average thickness 300 μm) was prepared as a substrate.

[Evaluation]
With respect to the abrasives of Examples 1 to 3 and Comparative Examples 1 to 4, the following criteria were used to evaluate the life of the abrasive, the separation between the base material and the polished portion, and the dripping during printing. The results are shown in Table 1.

<Abrasive life>
It is considered that the life of the abrasive is determined by the average thickness of the polished portion. Therefore, the following criteria were used.
A: The average thickness of the polished part is 1000 μm, and the life is long.
B: The average thickness of the polished part is 300 μm, and the life is slightly short.

<Peeling between base material and polishing part>
After bending the obtained abrasive, it was visually determined whether or not peeling between the substrate and the polished portion had occurred.
A: Peeling between the substrate and the polished part is observed.
B: Peeling between the substrate and the polished portion was not observed.

<Drip when printing>
If dripping occurs during printing, the printed pattern will be deformed after drying and curing. It was determined whether or not this deformation had occurred by visual inspection of the obtained abrasive.
A: No deformation of the printed pattern is observed after drying and curing.
B: Deformation of the printed pattern is observed after drying and curing.

  In Table 1, "PC" of the substrate means polycarbonate, "PET" means biaxially stretched polyethylene terephthalate, and "Al" means an aluminum plate.

  From Table 1, in the abrasives of Examples 1 to 3, peeling between the base material and the polished portion and deformation of the printed pattern after drying and curing due to dripping are not recognized regardless of the thickness of the polished portion. On the other hand, in the abrasives of Comparative Examples 1 to 3, deformation of the printed pattern after drying and curing due to dripping is observed, and in the abrasive of Comparative Example 4, peeling between the base material and the polished portion is observed.

  It is considered that since the abrasives of Comparative Examples 1 to 3 did not contain fumed silica, dripping occurred and deformation of the printed pattern after drying and curing was observed. In the abrasive of Comparative Example 4, although the deformation of the printed pattern after drying and curing due to dripping was suppressed by including fumed silica, peeling between the substrate and the polished portion occurred because the substrate was an aluminum plate. It is considered that

  From the above results, by adding fumed silica to the polished portion and using a heat-resistant resin as the main component of the base material, dripping can be suppressed and a columnar thick polished portion can be formed. It can be understood that the life can be prolonged while suppressing the decrease in the temperature.

  The polishing material of the present invention and the polishing material manufactured by the method of manufacturing the polishing material of the present invention can increase the thickness of the polished portion while suppressing a decrease in the polishing rate. Therefore, the abrasive of the present invention and the abrasive manufactured by the method of manufacturing an abrasive of the present invention can have a long life while exhibiting a stable polishing rate.

1, 2 Abrasive material 10 Base material 20 Polishing layer 20a Polishing portion 20b Groove 21 Abrasive grains 22 Binder 23 Fumed silica 30 Adhesive layer 31 Second adhesive layer 40 Support

Claims (5)

A polishing material comprising a base material and a polishing layer laminated on the surface side of the base material and containing abrasive grains and a binder,
The polishing layer has a plurality of columnar polishing portions,
The polishing section contains fumed silica,
An abrasive whose base material is mainly a heat-resistant resin.   2. The abrasive according to claim 1, wherein the content of the fumed silica in the polishing section is 0.1% by volume or more and 20% by volume or less.   The abrasive according to claim 1, wherein the abrasive has an average thickness of 300 μm or more and 5000 μm or less.   The abrasive according to claim 1, wherein the base material is polycarbonate or biaxially stretched polyethylene terephthalate. A method for producing an abrasive, comprising a base material and a polishing layer laminated on the surface side of the base material and containing abrasive grains and a binder,
Comprising a step of forming the polishing layer by printing a polishing layer composition,
The polishing layer has a plurality of columnar polishing portions,
The composition for the polishing layer contains fumed silica,
A method for producing an abrasive wherein the base material is mainly composed of a heat-resistant resin.

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