Abrasive pad

Abstract

The abrasive pad involved in this invention is an abrasive pad containing a polyurethane resin foam, having an abrasive surface formed by the surface of the polyurethane resin foam, wherein the polyurethane resin foam contains a plurality of air bubbles and has a porosity of 65% or more, and wherein the plurality of air bubbles contains large-diameter air bubbles with a diameter of 200 μm or more in a ratio of 15% or more.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to Japanese Patent Application No. 2020-7539, which is incorporated herein by reference. Technical Field

[0003] This invention relates to an abrasive pad. Background Technology

[0004] As abrasive pads for grinding objects such as silicon wafers or glass plates, abrasive pads with a grinding surface formed by polyurethane resin foam are known (e.g., Patent Document 1, etc.).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-274361 Summary of the Invention

[0008] Technical issues

[0009] In grinding using a grinding pad, a grinding slurry containing abrasive particles is typically introduced, and the grinding surface of the grinding pad slides into contact with the surface of the workpiece being ground (the grinding surface).

[0010] In order to improve work efficiency, it is required to increase the grinding rate in such grinding processes.

[0011] However, if the goal is to increase the grinding rate, the surface quality of the workpiece after grinding is likely to decrease. Therefore, there is a trade-off between increasing the grinding rate and the resulting quality of the workpiece.

[0012] Therefore, in view of the above-mentioned situation, the present invention aims to provide an abrasive pad that can easily abrade the workpiece at a high abrasive rate, and even when abrading is performed at a high abrasive rate, the surface quality of the workpiece after abrasion is not easily reduced.

[0013] Solution to the problem

[0014] The abrasive pad involved in this invention is an abrasive pad containing polyurethane resin foam.

[0015] It has a grinding surface.

[0016] The grinding surface is formed by the surface of the aforementioned polyurethane resin foam.

[0017] The polyurethane resin foam contains multiple air bubbles and has a porosity of 65% or more. Among the multiple air bubbles, large-diameter air bubbles with a diameter of 200 μm or more account for 15% or more of the total number of air bubbles. Attached Figure Description

[0018] Figure 1 This is a graph showing the temperature change of the storage modulus E' in the polyurethane resin foam of the abrasive pads of the embodiments and comparative examples.

[0019] Figure 2 This is a graph showing the temperature change of the loss modulus E” in the polyurethane resin foam of the abrasive pads of the embodiments and comparative examples.

[0020] Figure 3 This is a graph showing the temperature change of tanδ of the abrasive pads in the embodiments and comparative examples.

[0021] Figure 4 This is a graph showing the distribution curves of bubble diameter based on the number of polyurethane resin foams in the embodiments and comparative examples.

[0022] Figure 5 This is a graph showing the cumulative frequency distribution curves of bubble diameter based on the number of polyurethane resin foams in the embodiments and comparative examples.

[0023] Figure 6 This is a SEM image of the surface of the polyurethane resin foam of Comparative Example 1.

[0024] Figure 7 This is a SEM image of the surface of the polyurethane resin foam of Comparative Example 2.

[0025] Figure 8 This is a SEM image of the surface of the polyurethane resin foam of Comparative Example 3.

[0026] Figure 9 This is a SEM image of the surface of the polyurethane resin foam of Example 1. Detailed Implementation

[0027] Hereinafter, one embodiment of the present invention will be described.

[0028] The abrasive pad involved in this embodiment is an abrasive pad containing a polyurethane resin foam having polyurethane resin.

[0029] In addition, the abrasive pad according to this embodiment has an abrasive surface, which is formed by the surface of the polyurethane resin foam described above.

[0030] In this embodiment, the grinding pad is prepared by placing a grinding slurry containing abrasive particles between the grinding surface and the surface of the workpiece (the surface to be ground), thereby making the grinding surface and the surface to be ground slide in contact and grinding the surface.

[0031] The polyurethane resin foam contains multiple air bubbles and has a porosity of 65% or more. Among the multiple air bubbles, large-diameter air bubbles with a diameter of 200 μm or more account for 15% or more of the total number of air bubbles.

[0032] The abrasive pad involved in this embodiment, as described above, has a porosity of up to 65% or more in the polyurethane resin foam.

[0033] Therefore, compared with polyurethane resin foam with low porosity, the grinding pad involved in this embodiment has excellent deformability of the grinding surface, and the grinding surface exhibits good adhesion to the surface of the workpiece during grinding.

[0034] In the grinding surface of the grinding pad according to this embodiment, the air bubbles contained in the polyurethane resin foam are in an open state, so the grinding slurry is contained in the air bubbles during grinding.

[0035] The grinding pad described in this embodiment has a larger total area of ​​open air bubbles in the grinding surface compared to polyurethane resin foam with low porosity.

[0036] Therefore, the grinding pad according to this embodiment has a high retention rate of grinding slurry in the grinding surface.

[0037] Furthermore, the grinding pad of this embodiment, which has excellent deformability in the grinding surface, allows the grinding slurry contained in the air bubbles to quickly seep out to the grinding surface when the grinding surface is subjected to pressure due to the object being ground.

[0038] The abrasive pad of this embodiment, as described above, contains large-diameter bubbles with a bubble diameter of 200 μm or more in the polyurethane resin foam at a ratio of 15% or more.

[0039] Therefore, the depth of the air bubbles in the grinding surface is relatively deep.

[0040] During grinding, a portion of the material being ground is removed from the surface being ground, forming powdery grinding debris. As grinding progresses, air bubbles may sometimes become clogged. However, the grinding pad described in this embodiment has a large capacity for collecting grinding debris, making it less prone to clogging.

[0041] By adequately supplying slurry between the grinding surface and the workpiece, a high grinding rate can be achieved in grinding using the grinding pad of this embodiment.

[0042] During grinding, if a section of the grinding slurry is interrupted, a slippery phenomenon may occur at that section, raising concerns about damage to the surface of the workpiece being ground. However, this concern can be suppressed when using the grinding pad of this embodiment.

[0043] The abrasive pad of this embodiment has a high porosity and contains multiple large-diameter bubbles with a diameter of 200 μm or more. Therefore, the distance between adjacent bubbles is short, and pores are easily formed in the polyurethane resin (hereinafter also referred to as "bubble film") that forms a film between adjacent bubbles.

[0044] The abrasive pad of this embodiment has a plurality of air bubbles that are connected in the thickness direction through the aforementioned holes.

[0045] The grinding debris collected in the bubble opening at the grinding surface moves to the bubble below it, away from the grinding surface.

[0046] During grinding, if there are many grinding debris between the grinding surface and the workpiece, it is sometimes difficult to achieve a sufficiently good surface quality for the workpiece after grinding.

[0047] If the grinding rate is increased, the amount of grinding debris generated per unit time also increases. However, in grinding using the grinding pad of this embodiment, since the grinding debris can be kept away from the grinding surface, the surface of the workpiece after grinding can form a good quality.

[0048] In order to more fully realize the functions described above, the porosity of the polyurethane resin foam is preferably 70% or more, and more preferably 72% or more.

[0049] The porosity is preferably 80% or less, more preferably 78% or less.

[0050] It is important that the ratio of large-diameter air bubbles in the polyurethane resin foam is 15% or more, more preferably 20% or more, and even more preferably 25% or more.

[0051] The above ratio is usually below 30%.

[0052] In addition, the average bubble diameter of the plurality of bubbles in the polyurethane resin foam is preferably 110 μm or more, and more preferably 120 μm or more.

[0053] The abrasive pad of this embodiment has the advantage of being able to form pores more easily in the aforementioned bubble film because the polyurethane resin foam has a high average bubble diameter.

[0054] The average bubble diameter is preferably below 200 μm.

[0055] The average bubble diameter, the ratio of large-diameter bubbles, and the porosity can be obtained using an X-ray CT scanning device (e.g., the TDM1000H-I manufactured by Yamato Scientific Co., Ltd.) as follows.

[0056] That is, the volume of each bubble contained in the polyurethane resin foam within the measurement range (for example, two 0.7mm×1.6mm×1.6mm portions) is measured, and the diameter of each bubble is taken as the diameter of a sphere with the same volume.

[0057] In addition, the "average bubble diameter" refers to the arithmetic mean of the bubble diameters calculated from the volume of each bubble [=(total value of "diameter of each bubble") / (number of bubbles)].

[0058] In addition, the "ratio of large-diameter bubbles" refers to the proportion of large-diameter bubbles in the total number of bubbles, calculated from the diameter values ​​of each bubble obtained.

[0059] Moreover, porosity refers to the ratio of the total volume of air bubbles to the volume of the polyurethane resin foam being measured.

[0060] In this embodiment, the abrasive pad preferably exhibits good following of the abrasive surface of the workpiece being abraded.

[0061] Therefore, polyurethane resin foam is preferably selected with a JIS-A hardness of 75 or below.

[0062] Furthermore, JIS-A hardness is determined according to the method (Type A) of JIS K6253-3:2012. In this test, multiple sheets of polyurethane resin foam are stacked to a thickness of 12 mm or more when the thickness of the polyurethane resin foam is less than 12 mm, and the hardness of the stack is then measured. Additionally, JIS-A hardness refers to the hardness measured by pressing a button into a polished surface.

[0063] More preferably, the polyurethane resin foam prepared into a polishing surface has a JIS-A hardness of 70 or less.

[0064] The JIS-A hardness is further preferably 68 or less.

[0065] The JIS-A hardness is preferably 40 or higher, and more preferably 50 or higher.

[0066] From the viewpoint that the polyurethane resin foam exhibits good conformability to the surface of the workpiece being ground, the compression ratio is preferably 3% or more, and more preferably 4% or more.

[0067] Regarding compression ratio, similar to JIS-A hardness, the grinding surface can be used as the test object, or a polyurethane resin foam in the same state as the polyurethane resin foam constituting the grinding surface can be separately manufactured and used as the test object.

[0068] In addition, the compression ratio can be determined using the following method.

[0069] That is, the compression elasticity testing machine described in JIS L1096:2010 (compression element area: 50 mm²) can be used. 2 ), using pressure quantum at 300gf / cm 2 The pressure was applied to the polyurethane resin foam along its thickness direction, and the thickness T1 of the polyurethane resin foam was measured after holding the pressure for 60 seconds. Next, a pressure bar was used at 1800 gf / cm². 2 The pressure is applied to the polyurethane resin foam along the thickness direction, and the thickness T2 of the polyurethane resin foam is measured after holding the pressure for 60 seconds. The compression ratio is then calculated using the following formula.

[0070] Compression ratio = (T1 - T2) × 100 / T1

[0071] From the viewpoint that polyurethane resin foam can effectively follow the surface of the workpiece being ground, it is preferable that the storage modulus at 20°C is less than 50 MPa.

[0072] The storage modulus E' of the polyurethane resin foam at 20°C is more preferably 45 MPa or less, and even more preferably 40 MPa or less.

[0073] The storage modulus E' of polyurethane resin foam is typically above 20 MPa.

[0074] Since polyurethane resin foams are often used in the temperature range of 20°C to 50°C, it is preferable that the dynamic viscoelastic properties do not change significantly within this entire temperature range.

[0075] That is, the polyurethane resin foam preferably has a storage modulus E' of 20 to 50 MPa between 20°C and 50°C.

[0076] The energy storage modulus E' within this temperature range is more preferably 20–45 MPa, and even more preferably 20–40 MPa or less.

[0077] The polyurethane resin foam preferably has a tanδ (loss modulus E” / storage modulus E’) of 0.1 or higher at 20°C.

[0078] The polyurethane resin foam preferably has a tanδ (loss modulus E” / storage modulus E’) of 0.1 or higher at 50°C.

[0079] It should also be noted that the tanδ at 20℃ and 50℃ is usually below 0.15.

[0080] The tanδ value is preferably above 0.1 over the entire temperature range of 20℃ to 50℃.

[0081] The ratio of the tanδ value at 50℃ (tanδ(50℃)) to the tanδ value at 20℃ (tanδ(20℃)) (tanδ(50℃) / tanδ(20℃)) is preferably greater than 0.9 and less than 1.1.

[0082] Because the abrasive pad has a large tanδ (above 0.10), it can suppress the minute vibrations of the workpiece during abrasion, thereby preventing the workpiece from tipping over. As a result, the abrasive pad and the workpiece easily adhere to each other during abrasion.

[0083] As a result, the abrasive pad can improve flatness.

[0084] Storage modulus E' and loss modulus E” can be determined according to JIS K7244-4:1999 “Plastics – Test methods for dynamic mechanical properties – Part 4: Tensile vibration – Non-resonance method” under the following conditions.

[0085] Measurement temperature range: 0℃~100℃;

[0086] Heating rate: 5℃ / minute;

[0087] Frequency: 1Hz;

[0088] Strain: 0.5%.

[0089] Furthermore, the apparent density of the aforementioned polyurethane resin foam is preferably 0.3–0.4 g / cm³. 3 .

[0090] The apparent density is preferably 0.37 g / cm³. 3 .

[0091] In addition, apparent density can be determined according to JIS K7222:2005.

[0092] The polyurethane resin constituting the above-mentioned polyurethane resin foam can be the same polyurethane resin used in the abrasive pad.

[0093] The polyurethane resin has a first constituent unit comprising a compound containing active hydrogen (hereinafter also referred to as "active hydrogen compound") and a second constituent unit comprising a compound containing an isocyanate group (hereinafter also referred to as "isocyanate compound").

[0094] In addition, in the polyurethane resin described above, the active hydrogen compound and the isocyanate compound are bonded by carbamic acid to form a structure in which the first constituent unit of the active hydrogen compound and the second constituent unit of the isocyanate compound are alternately repeated.

[0095] The aforementioned active hydrogen compounds are organic compounds containing an active hydrogen group within their molecules that can react with an isocyanate group. Specifically, functional groups such as hydroxyl, primary amino, secondary amino, and thiol groups can be listed. The aforementioned active hydrogen compounds may have only one such functional group in their molecules or may have multiple such functional groups in their molecules.

[0096] As the aforementioned active hydrogen compound, for example, polyol compounds having multiple hydroxyl groups in the molecule, or polyamine compounds having multiple primary or secondary amino groups in the molecule, can be used.

[0097] Examples of the aforementioned polyol compounds include polyol monomers and polyol polymers.

[0098] Examples of the aforementioned polyol monomers include, for example, straight-chain aliphatic diols such as 1,4-benzenedimethanol, 1,4-bis(2-hydroxyethoxy)benzene, ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 1,9-nonanediol; branched-chain aliphatic diols such as neopentanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, and 2-methyl-1,8-octanediol; alicyclic diols such as 1,4-cyclohexanediol, 1,4-cyclohexanediol, and hydrogenated bisphenol A; and multifunctional polyols such as glycerol, trimethylolpropane, trihydroxybutylpropane, pentaerythritol, and sorbitol.

[0099] Ethylene glycol and diethylene glycol are preferred as the aforementioned polyol monomers in terms of easier improvement in strength during reaction, easier improvement in rigidity of the manufactured abrasive pad containing foamed polyurethane, and relatively low cost.

[0100] Examples of the aforementioned polyol polymers include: polyester polyols, polyester polycarbonate polyols, polyether polyols, and polycarbonate polyols.

[0101] In addition, as a polyol polymer, polyfunctional polyol polymers with more than three hydroxyl groups in the molecule can also be listed.

[0102] Examples of the aforementioned polyester polyols include: poly(ethylene adipate diol), poly(butylene adipate diol), polycaprolactone polyol, and poly(hexamethylene adipate diol).

[0103] Examples of the aforementioned polyester polycarbonate polyols include reaction products of polyester diols such as polycaprolactone polyols with hydrocarbon carbonates, as well as reaction products obtained by further reacting the reaction mixture of ethylene carbonate and polyols with organic dicarboxylic acids.

[0104] Examples of polyether polyols mentioned above include: polytetramethylene ether glycol (PTMG), polypropylene glycol (PPG), polyethylene glycol (PEG), and ethylene oxide addition polypropylene polyols.

[0105] Examples of polycarbonate polyols mentioned above include: reaction products of diols such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene ether glycol with phosgene, diallyl carbonate (e.g., diphenyl carbonate), or cyclic carbonates (e.g., propylene carbonate).

[0106] Other examples of polyol compounds mentioned above include: diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and polyethylene glycol with a molecular weight of less than 400.

[0107] Examples of the aforementioned polyamine compounds include: 4,4'-methylenebis(2-chloroaniline) (MOCA), 4,4'-methylenediphenylamine, trimethylenebis(4-aminobenzoate), 2-methyl-4,6-bis(methylthio)phenyl-1,3-diamine, 2-methyl-4,6-bis(methylthio)-1,5-phenylenediamine, 2,6-dichloro-p-phenylenediamine, and 4,4'-methylenebis(2,3-dichlorophenyl)phenyl (Amines), 3,5-bis(methylthio)-2,4-toluenediamine, 3,5-bis(methylthio)-2,6-toluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, trimethylene glycol-di-p-aminobenzoate, 1,2-bis(2-aminophenylthio)ethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, etc.

[0108] Examples of the aforementioned polyisocyanates include: polyisocyanate monomers and polyisocyanate polymers.

[0109] Examples of polyisocyanate monomers include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates.

[0110] Examples of the aforementioned aromatic diisocyanates include: toluene diisocyanate (TDI), 1,5-naphthalene diisocyanate, phenyl dimethyl diisocyanate, 1,3-phenylene diisocyanate, and 1,4-phenylene diisocyanate. Additionally, examples of the aforementioned aromatic diisocyanates include: diphenylmethane diisocyanate (MDI) and modified forms of diphenylmethane diisocyanate (MDI).

[0111] Examples of modifiers for diphenylmethane diisocyanate include: carbodiimide-modified compounds, carbamic acid-modified compounds, urea-modified compounds, biuret-modified compounds, isocyanurate-modified compounds, and oxazolidinone-modified compounds. Specifically, an example of such a modifier is carbodiimide-modified diphenylmethane diisocyanate (carbodiimide-modified MDI).

[0112] Examples of aliphatic diisocyanates mentioned above include: ethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate (HDI).

[0113] Examples of the aforementioned alicyclic diisocyanates include: 1,4-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, methylene bis(4,1-cyclohexene) diisocyanate, etc.

[0114] Examples of the aforementioned polyisocyanate polymers include polymers formed by combining polyols with at least one of aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates.

[0115] From the viewpoint of improving the tanδ of polyurethane resin foam, the polyurethane resin preferably contains polypropylene glycol (PPG) as a constituent unit.

[0116] In addition, the polyurethane resin mentioned above has a brittle structure by including polypropylene glycol (PPG) as a constituent unit, which results in the advantage of increased cutting speed of the abrasive pad during dressing.

[0117] Furthermore, in the abrasive pad according to this embodiment, when the polyurethane resin is 100% by mass, the content of polypropylene glycol (PPG) contained in the constituent unit of the polyurethane resin is preferably 30% by mass or more, more preferably 40 to 70% by mass, and even more preferably 50 to 65% by mass.

[0118] Furthermore, when the polyurethane resin is 100% by mass, the proportion of polypropylene glycol (PPG) contained in the constituent units of the polyurethane resin can be obtained by the following operation.

[0119] First, the polyurethane resin foam was dissolved in a polar solvent (heavy DMF, heavy DMSO, etc.) to obtain a solution. Next, the polypropylene glycol (PPG) content was quantified by analyzing the solution using 1H-NMR to determine the proportion of PPG contained in the solution.

[0120] In addition, the following methods are other ways to calculate the content ratio of the aforementioned polypropylene glycol (PPG).

[0121] First, the polyurethane resin foam was chemically decomposed using methanol to obtain decomposition products. Next, these decomposition products were separated and fractionated using gel permeation chromatography (GPC), and each fraction was analyzed using 1H-NMR or GC-MS to quantify the polypropylene glycol (PPG) and determine its content ratio.

[0122] Examples of objects to be polished using the polishing pad described in this embodiment include: optical materials, semiconductor devices, hard disks, glass plates, silicon wafers, etc.

[0123] In addition, the polishing pad described in this embodiment is suitable for polishing silicon wafers and glass plates.

[0124] Furthermore, the abrasive pad described in this embodiment is also suitable for fine grinding, precision grinding, and the like.

[0125] Furthermore, the abrasive pads involved in this invention are not limited to the embodiments described above. The abrasive pads involved in this invention are also not limited to the effects described above. Moreover, various modifications can be made to the abrasive pads involved in this invention without departing from the essential points of this invention.

[0126] Example

[0127] The present invention will now be further illustrated with examples and comparative examples.

[0128] Prepared with the following Table 1 and Figures 1-5 The abrasive pad with the characteristics shown is a sheet-like polyurethane resin foam.

[0129] In addition, the following Table 1 and Table 2 were measured using the methods described above. Figures 1-3 The characteristics shown.

[0130] in addition, Figure 4 The "distribution curve of bubble diameter based on number" shown is as follows: Figure 5 The "cumulative frequency distribution curve of bubble diameter based on number" shown is obtained by the following method.

[0131] First, the diameter of the bubble is determined using the method described above.

[0132] Subsequently, within the bubble diameter range of 0μm to 600μm, the number of bubbles was calculated at 50μm intervals. The curve created using the "number of bubbles in each interval" as the "number of bubbles with the upper limit of the bubble diameter in each interval" was used as the "distribution curve of bubble diameter based on the number of bubbles".

[0133] In addition, the cumulative frequency distribution curve of bubble diameter based on the number of bubbles is constructed using data from the distribution curve of bubble diameter based on the number of bubbles.

[0134] Furthermore, SEM images of the surfaces of the abrasive pads in Comparative Examples 1-3 and Example 1 are shown below. Figures 6-9 .

[0135] Furthermore, the abrasive pads of Comparative Examples 1 to 3 are commercially available abrasive pads.

[0136] [Table 1]

[0137]

[0138] (Evaluation Test)

[0139] Using an abrasive pad, grind the workpiece under the following conditions and determine the abrasion rate.

[0140] <Device>

[0141] Grinding machine: NH-5B2MT (KOEI);

[0142] Dresser: Dresser #120.

[0143] <Break-in conditions>

[0144] Time: 60 minutes (Comparative Example 1), 60 minutes (Comparative Example 2)

[0145] 160 minutes (Comparative Example 3), 220 minutes (Example 1);

[0146] Fixed plate speed: 20 rpm;

[0147] DI water flow rate: 3L / minute.

[0148] <Grinding conditions>

[0149] Material to be ground: Sodium-calcium glass plate (thickness: approximately 700 μm, diameter: 65 mm);

[0150] Grinding slurry: Grinding slurry containing 20% ​​by mass of CeO2;

[0151] Flow rate of grinding slurry: 450 mL / min;

[0152] Grinding time: 25 minutes / roll;

[0153] Load: 142 gf / cm 2 ;

[0154] Fixed plate speed: 45 rpm.

[0155] The grinding speed is calculated by dividing the thickness reduction achieved through grinding by the grinding time. Furthermore, the thickness reduction achieved through grinding is calculated from the mass difference between the workpiece before and after grinding.

[0156] In addition, regarding the number of micro-scratches, a magnified image (magnification: 100x) of a portion of the ground surface of the soda-lime glass plate (2.5mm × 3.4mm) was obtained using a microscope (VHX-5000DIGITALMICROSCOPE manufactured by Keyence). The number of scratches in the magnified image was confirmed by visual inspection, and the total number of scratches in the entire ground surface was taken as the number of micro-scratches.

[0157] The results of the evaluation experiment are shown in Table 2.

[0158] [Table 2]

[0159] Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Grinding rate (μm / min) 1.03 1.11 1.09 1.25 Number of micro-scratches 0 0 0 0

[0160] As shown in Table 2, when using the abrasive pad of the embodiment, the surface quality of the workpiece is not reduced, and a high abrasive rate can be achieved.

Claims

1. A polishing pad, characterized by, It is an abrasive pad containing polyurethane resin foam. The abrasive pad has an abrasive surface. The grinding surface is formed by the surface of the polyurethane resin foam. The polyurethane resin foam comprises multiple air bubbles with a porosity of 65% or more. Among these multiple air bubbles, a ratio of 15% to 30% consists of large-diameter air bubbles with a diameter of 200 μm or more. The average diameter of the multiple air bubbles is 200 μm or less. The storage modulus E' of the polyurethane resin foam at 20°C is above 20MPa and below 50MPa.

2. The abrasive pad according to claim 1, wherein, The average bubble diameter of the plurality of bubbles is greater than 110 μm.

3. The abrasive pad according to claim 1 or 2, wherein, The JIS-A hardness of the polyurethane resin foam is below 75.

4. The abrasive pad according to claim 1 or 2, wherein, The compression ratio of the polyurethane resin foam is 3% or more.

5. The abrasive pad according to claim 1 or 2, wherein, The tanδ of the polyurethane resin foam at 20°C is 0.1 or more, and the tanδ of the polyurethane resin foam at 50°C is 0.1 or more, wherein tanδ is the ratio of the loss modulus E'' to the storage modulus E' of the polyurethane resin foam.

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