Lapping pad, manufacturing method thereof, and manufacturing method of lapped product

Abstract

To provide a wrapping pad which is excellent in dress property and prevents smoothing of a surface.SOLUTION: A wrapping sheet includes a resin sheet having a pore, in which in pore distribution of the resin sheet measured by a mercury press-in method at a contact angle of 130° and mercury surface tension of 485 dyn / cm, an integral pore volume V in a range of a pore size of 0.010 μm or more and 1.0 μm or less is 0.21 cm3 / g or more and 1.00 cm3 / g or less, and density of the resin sheet is 0.3 g / cm3 or more and 0.9 g / cm3 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a lapping pad, a method for manufacturing the same, and a method for manufacturing a lapped product. [Background technology]

[0002] Generally, grinding, lapping, and polishing are performed on materials such as optical materials such as lenses, plane-parallel plates, and reflecting mirrors, semiconductor wafer materials such as SiC disks, crystals, metals, stone, wood, resin materials, and ceramics, and a lapping pad is used in the lapping process.

[0003] As a technique related to lapping, for example, Patent Document 1 discloses a platen and a polymer material attached to the platen, the density of the polymer material being about 0.7 g / cm 3 ~About 3.0g / cm 3 Patent Document 1 discloses a lapping system that includes a polymer material and a slurry that includes abrasive particles. Patent Document 1 states that lapping using such a polymer material enables processing at a high removal rate over a long period of time, with few defects caused by the processing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2018-524193 Summary of the Invention [Problem to be solved by the invention]

[0005] Resin sheets used in lapping processes involving free abrasive grains (slurry) have the following requirements. Specifically, slurries containing high-hardness abrasive grains (especially superabrasive grains), such as diamond, are often used in lapping processes. In recent years, there has been a demand for reducing excessive scratching during lapping processes to reduce the cost of finish polishing. One possible solution to this requirement is to adjust the density of the resin sheet. For example, using a low-density resin sheet tends to retain the abrasive grains within the foam of the resin sheet, preventing the abrasive grains from strongly contacting the workpiece and causing scratches. On the other hand, simply lowering the density tends to cause deterioration of the surface smoothness over time due to glazing during long-term use. Therefore, there is a need for a resin sheet that has the brittleness to allow for the ability to reveal grains through dressing (so-called dressability) and / or the ability to self-regenerate, i.e., the surface wears without smoothing and a new surface emerges, without affecting physical properties. From this perspective, the technology described in Patent Document 1 still leaves room for improvement.

[0006] The present invention has been made in consideration of the above problems, and aims to provide a lapping pad that has excellent dressability and a surface that is difficult to smooth, a method for manufacturing the same, and a method for manufacturing a lapped product. [Means for solving the problem]

[0007] As a result of extensive research into solving the above problems, the present inventors have found that the above problems can be solved by using a resin sheet having predetermined physical properties, and have thus completed the present invention.

[0008] That is, the present invention includes the following aspects. [1] A wrapping pad comprising a resin sheet having fine holes, In the pore distribution of the resin sheet measured by mercury intrusion porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm, the cumulative pore volume V in the pore diameter range of 0.010 μm or more and 1.0 μm or less was 0.21 cm 3 / g or more 1.00cm 3 / g or less, The density of the resin sheet is 0.3 g / cm 3 More than 0.9g / cm 3 Below is the wrapping pad. [2] The wrapping pad according to [1], wherein in the pore distribution of the resin sheet, the ratio of the cumulative pore volume V to the cumulative pore volume V0 in the pore diameter range of 0.010 μm or more and 360 μm or less is 50% or more. [3] The wrapping pad according to [1] or [2], wherein the resin sheet has an average pore size of 50 μm or more and 200 μm or less, as measured for pores of 10 μm or more. [4] The wrapping pad according to any one of [1] to [3], wherein in the pore distribution of the resin sheet, the peak position of the maximum peak in the pore diameter range of 0.010 μm or more and 360 μm or less is within the pore diameter range of 0.010 μm or more and 1.0 μm or less. [5] The wrapping pad according to any one of [1] to [4], wherein the resin sheet has a microphase separation structure. [6] The wrapping pad according to any one of [1] to [5], wherein the resin sheet contains polyurethane. [7] A method for producing the wrapping pad according to any one of [1] to [6], A method for producing a wrapping pad, comprising a step of curing a mixed liquid of at least one prepolymer and at least two curing agents to obtain a resin sheet having a microphase-separated structure. [8] [7] The method for manufacturing a wrapping pad described in [7], wherein the curing agent includes a first curing agent having an NH2 equivalent of 100 or more and 300 or less, and a second curing agent having an OH equivalent of 1000 or more and 2000 or less. [9] A method for producing a lapped product, comprising a lapping step of lapping a workpiece using the lapping pad according to any one of [1] to [6] in the presence of a slurry. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a lapping pad that has excellent dressability and whose surface is difficult to smooth, a method for manufacturing the same, and a method for manufacturing a lapped product. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 shows the results of measuring the cumulative pore volume (pore distribution) of the resin sheet of Example 1 by mercury intrusion porosimetry. [Figure 2] FIG. 2 is an SEM image of the surface of the resin sheet of Example 1 observed with a scanning electron microscope at 500 magnifications. [Figure 3] Fig. 3(A) is an SEM image of the surface of the resin sheet of Example 1, observed at 2000x magnification using a scanning electron microscope. Fig. 3(B) shows the area in Fig. 3(A) where a microphase-separated structure (gyroid structure) was observed, surrounded by a dashed line. [Figure 4] FIG. 4 shows the results of measuring the cumulative pore volume (pore distribution) of the resin sheet of Example 2 by mercury intrusion porosimetry. [Figure 5] FIG. 5 is an SEM image of the surface of the resin sheet of Example 2 observed with a scanning electron microscope at 500 magnifications. [Figure 6] FIG. 6 shows the results of measuring the cumulative pore volume (pore distribution) of the resin sheet of Comparative Example 1 by mercury porosimetry. [Figure 7] FIG. 7 is an SEM image of the surface of the resin sheet of Comparative Example 1 observed with a scanning electron microscope at 500 magnifications. DETAILED DESCRIPTION OF THE INVENTION

[0011] Below, we will explain in detail the embodiment of the present invention (hereinafter referred to as the ``present embodiment''), but the present invention is not limited to this and various modifications are possible within the scope of the gist of the present invention.

[0012] (wrapping pad) The lapping pad of this embodiment is a lapping pad comprising a resin sheet having pores, and in the pore distribution of the resin sheet measured by mercury porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm, the cumulative pore volume V in the pore diameter range of 0.010 μm or more and 1.0 μm or less is 0.21 cm 3 / g or more 1.00cm 3 / g or less, and the density of the resin sheet is 0.3 g / cm 3 More than 0.9g / cm 3 The lapping pad of this embodiment is configured as described above, and therefore has excellent dressability and its surface is less likely to become smooth.

[0013] The wrapping pad of the present embodiment is not particularly limited as long as it includes the resin sheet of the present embodiment, and the wrapping pad may have a configuration other than the resin sheet. Examples of the configuration other than the resin sheet in the wrapping pad include a wrapping layer, a cushion layer, and an adhesive layer, which are conventionally known.

[0014] The lapping pad of this embodiment preferably has the above-mentioned resin sheet as a lapping layer. "Having a resin sheet as a lapping layer" means that at least one surface of the lapping pad of this embodiment corresponds to the surface of the resin sheet of this embodiment, and that surface of the resin sheet becomes the lapping surface that is pressed against the workpiece during the lapping process of this embodiment. Therefore, the lapping pad of this embodiment preferably has at least one surface made of the resin sheet of this embodiment. Alternatively, the lapping pad of this embodiment may consist solely of the resin sheet of this embodiment.

[0015] The lapping pad of this embodiment may have grooves, embossing, and / or holes (punching) on ​​the lapping surface as needed, and may also have a light-transmitting portion. The shape of the grooves and embossing is not particularly limited, and examples thereof include a lattice shape, a concentric circle shape, and a radial shape.

[0016] (resin sheet) (density) The resin sheet in this embodiment has a density of 0.3 g / cm 3 More than 0.9g / cm 3 The density of the resin sheet in this embodiment is 0.3 g / cm or less. 3 In this case, the lapping pad is less likely to deform under pressure, and therefore, during lapping, the force applied from the lapping pad to the workpiece becomes uniform in the direction of the lapping surface. As a result, during lapping using a lapping pad equipped with such a resin sheet, the surface of the workpiece can be made even flatter. In this specification, "the surface of the workpiece is flat" means that the lapped surface of the workpiece is flatter overall. This can also be expressed as having good global flatness. From the same perspective, the density of the resin sheet in this embodiment is preferably 0.4 g / cm 3 More preferably, 0.45 g / cm 3 That's all. On the other hand, the density of the resin sheet in this embodiment is 0.9 g / cm 3 If the thickness is less than this, it is possible to prevent the abrasive grains from coming into strong contact with the workpiece and causing scratches. In addition, the hardness of the resin sheet tends to be low, which also tends to prevent scratches from occurring. The density of the resin sheet in this embodiment can be measured by a conventional method. For example, the mass and volume of a resin sheet piece can be measured by a conventional method, and the density can be calculated from the obtained values. The method for controlling the density of the resin sheet is not particularly limited, but for example, a wrapping pad can be obtained by the wrapping pad manufacturing method of this embodiment described below. In particular, when the amount of foaming agent is reduced in the manufacturing process of the resin sheet in this embodiment, the density of the resin sheet tends to increase.

[0017] (Pore distribution of resin sheet) (cumulative pore volume V) The resin sheet in this embodiment has pores, and in the pore distribution of the resin sheet measured by mercury porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm, the cumulative pore volume V in the pore diameter range of 0.010 μm or more and 1.0 μm or less is 0.21 cm 3 / g or more 1.00cm 3 / g or less. In the following description, unless otherwise specified, the term "pore distribution" refers to a pore distribution measured by mercury porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm. Mercury porosimetry is a method for measuring the pore distribution on the surface of a sample by filling mercury into the pores on the surface of the sample while sweeping the applied pressure. Therefore, when measuring the pore distribution of a foamed material by mercury porosimetry, the pore distribution mainly reflects the pore distribution of interconnected cells (generally also referred to as "open cells"), and the contribution of the pore distribution of closed cells is small.

[0018] Regarding the lapping pad of this embodiment, the inventors have found that the cumulative pore volume V in the pore diameter range of 0.010 μm or more and 1.0 μm or less is 0.21 cm 3 in the pore distribution measured by mercury intrusion porosimetry. 3 / g or more, the affinity with the slurry in the lapping pad is sufficiently good. 3 / g or more, interconnected cells having a pore size of 0.010 μm or more and 1.0 μm or less are distributed throughout the resin sheet, and during lapping, the slurry penetrates uniformly into the resin sheet through the interconnected cells. However, when the cumulative pore volume V is 0.21 cm 3 The reason why the affinity of the lapping pad with the slurry is sufficiently good when the lapping pad has a SiO 2 content of 0.1g or more is not limited to the above. From the viewpoint of further improving the affinity with the slurry, in the resin sheet of this embodiment, the cumulative pore volume V is preferably 0.30 cm 3 / g or more, and more preferably 0.40 cm 3 / g or more. In the resin sheet of this embodiment, the cumulative pore volume V is 1.00 cm 3 / g or less. The cumulative pore volume V is 1.00 cm 3 / g or less, the density of the resin sheet tends to be within the above range, and in lapping using a lapping pad equipped with such a resin sheet, the surface of the workpiece can be made even flatter. From the same viewpoint, the cumulative pore volume V is preferably 0.90 cm 3 / g or less. The cumulative pore volume V is 0.21 cm 3 / g or more 1.00cm 3 When the surface roughness is within the range of 1 / g or less, the resin sheet has excellent dressability. The terms "dress" or "dressing process" refer to a process in which the surface roughness and flatness of the lapping surface of the lapping pad are adjusted using a dressing jig (e.g., a diamond dresser or sandpaper) with abrasive grains or the like fixed thereto before lapping the workpiece. The term "excellent dressability" refers to a process in which sufficient dressing can be performed by processing under relatively easy conditions. The term "lapping surface" refers to the surface that the lapping pad comes into contact with the workpiece, or the surface that is expected to come into contact with the workpiece, when lapping the workpiece with the lapping pad.

[0019] (Ratio of cumulative pore volume V to cumulative pore volume V0) In the lapping pad of this embodiment, from the viewpoint of further improving the balance between the flatness imparted to the workpiece and the affinity with the slurry, in the pore distribution of the resin sheet, the ratio of the cumulative pore volume V in the pore diameter range of 0.010 μm to 1.0 μm to the cumulative pore volume V0 in the pore diameter range of 0.010 μm to 360 μm is preferably 50% or more. In other words, the ratio (V / V0) of the cumulative pore volume V to the cumulative pore volume V0 is preferably 0.50 or more. According to this embodiment, the resin sheet has an increased proportion of pores having relatively small pore diameters, and therefore the number of interconnected cells in the resin sheet can be further increased while maintaining the density equivalent to that of conventional products. From the same viewpoint, the ratio of the integral pore volume V to the integral pore volume V0 is more preferably 60% or more, even more preferably 65% ​​or more, and even more preferably 70% or more. There is no particular upper limit to the ratio of the integral pore volume V to the integral pore volume V0, and the ratio of the integral pore volume V to the integral pore volume V0 may be 100% or less, 99% or less, 95% or less, 90% or less, 85% or less, or 80% or less.

[0020] (Peak position of the maximum peak) In the pore distribution of the resin sheet of this embodiment, the peak position of the maximum peak in the pore diameter range of 0.010 μm to 360 μm is preferably within the pore diameter range of 0.010 μm to 1.0 μm. Generally, in mercury intrusion porosimetry, the pore distribution is measured as the cumulative pore volume from the maximum pore diameter in the measurement range. Therefore, "the peak position of the maximum peak in the pore diameter range of 0.010 μm to 360 μm" refers to the position (pore diameter) of the maximum peak in the log differential pore volume distribution (dV / d(logD)) calculated from the pore distribution obtained by mercury intrusion porosimetry. Furthermore, when there are multiple maximum points in the pore diameter range of 0.010 μm to 360 μm, the maximum peak refers to the maximum point with the largest maximum value. When the peak position of the maximum peak in the pore diameter range of 0.010 μm to 360 μm is within the pore diameter range of 0.010 μm to 1.0 μm, the resin sheet has pores with a more uniform distribution in the range of 0.010 μm to 1.0 μm, which tends to further improve affinity with the slurry of the lapping pad and dressability. From the viewpoint of further improving affinity with the slurry of the lapping pad and dressability, the pore diameter is more preferably within the range of 0.010 μm to 0.5 μm, even more preferably 0.030 μm to 0.5 μm, and even more preferably 0.050 μm to 0.5 μm. From the same viewpoint, the position of the maximum peak in the range of 1.0 μm or more and 360 μm or less is more preferably in the range of pore diameters of 50 μm or more and 200 μm or less.

[0021] (Number of peaks and peak height) In the Log differential pore volume distribution of the resin sheet in this embodiment, the number of peaks in the pore diameter range of 0.010 μm to 360 μm is preferably 2 to 4, more preferably 2, and even more preferably 1 in the range of 0.010 μm to 1.0 μm and 1.0 μm to 360 μm. When the number of peaks is within the above range, the pores have a more uniform distribution, which tends to further improve the affinity of the lapping pad with the slurry and the dressability. From a similar viewpoint, in the Log differential pore volume distribution, the maximum peak height in the pore diameter range of 0.010 μm or more and 1.0 μm or less is preferably at least two times, more preferably at least 2.5 times, and even more preferably at least three times, the maximum peak height in the pore diameter range of 1.0 μm or more and 360 μm or less.

[0022] (cumulative pore volume V0) In the pore distribution of the resin sheet in this embodiment, the cumulative pore volume V0 in the pore diameter range of 0.010 μm or more and 360 μm or less is preferably 0.1 cm 3 / g or more 2.0cm 3 / g or less, and more preferably 0.4 cm 3 / g or more 2.0cm 3 / g or less, and more preferably 0.5 cm 3 / g or more 1.5cm 3 / g or less, and even more preferably 0.6 cm 3 / g or more 1.2cm 3 When the cumulative pore volume V0 is within the above range, the balance between the flatness imparted to the workpiece and the affinity with the slurry tends to be further improved.

[0023] In this embodiment, the cumulative pore volume V and the cumulative pore volume V0 are calculated from the pore distribution measured by mercury porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm, but for more detailed measurement conditions for the mercury porosimetry, the method described in the Examples can be referred to. Furthermore, the method for controlling the cumulative pore volume V, the cumulative pore volume V0, the ratio of the cumulative pore volume V to the cumulative pore volume V0, the peak position of the maximum peak, the number of peaks, and the peak height values ​​is not particularly limited, but for example, a lapping pad may be obtained by the method for producing a lapping pad of this embodiment described below.

[0024] (Structure of resin sheet) The resin sheet of this embodiment preferably has a microphase-separated structure. In this specification, the term "microphase-separated structure" refers to a phase-separated structure formed through microphase separation. Furthermore, in this specification, the term "microphase separation" refers to phase separation in which a microscopic (typically on the order of micrometers) structural pattern is repeated with at least one-dimensional periodicity in a macroscopically homogeneous object. Microphase separation can be achieved, for example, by employing preferred manufacturing conditions in the method for manufacturing a lapping pad of this embodiment, which will be described later. Typical examples of microphase-separated structures include, but are not limited to, a spherical structure (island-in-the-sea structure), a cylindrical structure, a lamellar structure, and a three-dimensional network structure. The microphase-separated structure of this embodiment preferably includes a cylindrical structure, a lamellar structure, and a three-dimensional network structure, and more preferably a three-dimensional network structure. In this specification, a three-dimensional network structure refers to a structure in which a mesh-like network is formed in three dimensions. The three-dimensional network structure derived from microphase separation may include a single gyroid structure and / or a double (multiple) gyroid structure. In this specification, a single gyroid structure typically refers to a network structure in which two twisted three-way branches combine to form a pair of thin wire structures, forming a unit cell, which is periodically repeated, and a double (multiple) gyroid structure refers to a structure in which two or more single gyroid structures are combined in a nested manner. In the cross section of a resin sheet having an open-cell structure resulting from conventional foaming agents or injecting an inert gas, a generally spherical foam cross section and flat resin regions (i.e., a sea-island structure of a resin sea and islands of voids) tend to be observed. On the other hand, when the resin sheet of the present embodiment has a double (multiple) gyroid structure, a phase-separated structure in which two or more resins are intertwined in a mottled pattern on the order of micrometers tends to be observed in the cross section. Furthermore, when the resin sheet of the present embodiment has a single gyroid structure, an amorphous void cross section and a resin skeleton / resin skeleton cross section are typically observed in the cross section. When the resin skeleton is sufficiently large compared to the voids, the resin skeleton may not be observable and the sheet may be observed as essentially a sea of ​​resin. However, even in this case, the voids in the resin sheet of the present embodiment are formed in a three-dimensional network-like interconnection. When a cross section of the resin sheet in this embodiment is observed, a mottled pattern of two or more resins, and characteristics of both an amorphous void cross section and a resin skeleton / resin skeleton cross section are observed. In other words, there are cases where the boundary between the double (multiple) gyroid structure and the single gyroid structure cannot be clearly distinguished, but in such cases, the resin sheet can be evaluated as including at least one of a single gyroid structure and a double (multiple) gyroid structure. Even when the resin sheet in this embodiment has a single gyroid structure and / or a double (multiple) gyroid structure, a sharp peak (maximum value) is typically measured in the pore diameter range of 0.010 μm or more and 10.0 μm or less in the Log differential pore volume distribution.

[0025] The resin sheet of this embodiment may include two or more phases with different compositions. In this specification, the "composition" of a phase includes both the resin that is the main component of the phase and the components other than the main component contained in the phase, and further takes into consideration the blending ratio of these. Therefore, the microphase-separated structure of the resin sheet of this embodiment may include two or more phases in which at least one of the resin that is the main component of the phase and the components other than the main component contained in the phase are different from each other, and typically includes two or more phases in which at least one or more of the structure, average molecular weight, and functional group of the resin that is the main component of the phase are different.

[0026] Examples of two phases with different compositions include a case where the types of resins constituting one phase are different from those constituting the other phase; a case where the amount of additives contained in one phase is different from those constituting the other phase; and a case where the resin sheet is made of an AB block polymer, and one phase is a phase mainly composed of the A block and the other phase is a phase mainly composed of the B block.

[0027] Typical examples of microphase-separated structures containing two phases with different compositions include a first phase formed by the curing of a predetermined prepolymer and a predetermined curing agent, and a second phase formed by the curing of a prepolymer different from the prepolymer in the first phase and the curing agent in the first phase; a first phase formed by the curing of a predetermined prepolymer and a predetermined curing agent, and a second phase formed by the curing of a prepolymer in the first phase and a curing agent different from the curing agent in the first phase; and a first phase formed by the curing of a predetermined prepolymer and a predetermined curing agent, and a second phase formed by the curing of a prepolymer different from the prepolymer in the first phase and a curing agent different from the curing agent in the first phase.

[0028] The resin sheet in this embodiment may have voids resulting from microphase separation. Such voids may be referred to as voids constituting a microphase-separated structure, and specific examples thereof include, but are not limited to, voids defined by a resin skeleton that gives a gyroid structure. In this specification, the voids may be derived from pores or from interconnected pores formed by interconnecting a plurality of pores.

[0029] The resin sheet having the microphase-separated structure of this embodiment can be obtained, for example, by the method for producing a wrapping pad of this embodiment described later. Furthermore, whether the resin sheet has the microphase-separated structure can be confirmed by observing it with a scanning electron microscope (SEM) at a magnification of about 300 to 3000 times.

[0030] The fact that the resin sheet has a microphase separation structure containing two or more phases with different compositions or that it has the above-mentioned voids can be observed using optical methods such as an optical microscope and a phase contrast microscope, methods using electron microscopes such as a scanning electron microscope and a transmission electron microscope, methods using particle scattering such as light scattering, small-angle neutron scattering, and small-angle X-ray scattering, X-ray diffraction methods, fluorescence methods, and pulsed NMR measurement methods.

[0031] (Average pore diameter of resin sheet) In the resin sheet of this embodiment, the average pore size measured for pores of 10 μm or more is not particularly limited, but is preferably 50 μm or more and 300 μm or less, and more preferably 50 μm or more and 200 μm or less. The average pore size can be measured, for example, by the method described in the Examples below. The average pore size can be adjusted to the above-mentioned range by, for example, adjusting the type and / or amount of foaming agent and foam stabilizer.

[0032] (average thickness of resin sheet) The average thickness of the resin sheet in this embodiment is not particularly limited, but is preferably 0.5 mm or more and 10.0 mm or less, more preferably 0.6 mm or more and 8.0 mm or less, and even more preferably 0.7 mm or more and 5.0 mm or less.

[0033] (Physical properties of resin sheet) The compressibility of the resin sheet in this embodiment is not particularly limited, but is preferably 0.1% or more and 5.0% or less, and more preferably 0.3% or more and 3.0% or less. The compressibility of the resin sheet can be determined using a Schopper-type thickness gauge (pressure surface: circular with a diameter of 1 cm) in accordance with Japanese Industrial Standards (JIS L 1021). Specifically, the thickness t0 is measured after applying an initial load from an unloaded state for 30 seconds, and then the thickness t1 is measured after applying a final pressure from the thickness t0 state for 30 seconds, and the compressibility can be calculated from the following formula. The initial load is 100 g / cm 2 , final pressure is 1120g / cm 2 is. Compression ratio (%) = 100 × (t0-t1) / t0

[0034] The compressive elastic modulus of the resin sheet in this embodiment is not particularly limited, but is preferably 70% or more and 100% or less, and more preferably 75% or more and 95% or less. The compressive elastic modulus of the resin sheet can be determined using a Schopper-type thickness gauge (pressure surface: circular, 1 cm diameter) in accordance with Japanese Industrial Standards (JIS L 1021). Specifically, the thickness t0 is measured after applying an initial load for 30 seconds from an unloaded state, then the thickness t1 is measured after applying a final pressure for 30 seconds from the thickness t0 state, and then all loads are removed from the thickness t1 state, the sheet is left for 5 minutes (unloaded state), and the thickness t0' is measured after applying the initial load again for 30 seconds, and the compressive elastic modulus can be calculated using the following formula. The initial load is 100 g / cm 2 , final pressure is 1120g / cm 2 is. Compression ratio (%) = 100 × (t0'-t1) / (t0-t1)

[0035] The Shore D hardness of the resin sheet in this embodiment is not particularly limited, but is preferably 10 or more and 70 or less, and more preferably 20 or more and 60 or less. The Shore D hardness of the resin sheet can be determined using a D-type hardness tester in accordance with Japanese Industrial Standards (JIS K 7311).

[0036] (Resin sheet material) The material of the resin sheet in this embodiment is not particularly limited. Examples of materials for the resin sheet include polyurethane resins. Examples of polyurethane resins include, but are not particularly limited to, polyester-based polyurethane resins, polyether-based polyurethane resins, and polycarbonate-based polyurethane resins. These may be used alone or in combination of two or more.

[0037] Among these, the resin sheet material in this embodiment preferably contains at least one of a polyester-based polyurethane resin and a polyether-based polyurethane resin. In particular, the resin sheet preferably contains a polyurethane resin that is a cured product of a mixed solution containing a urethane prepolymer and at least two curing agents, as described later in the method for manufacturing the wrapping pad of this embodiment. By using such a resin, the density and pore size distribution tend to be easily adjusted within the above-mentioned ranges.

[0038] The resin sheet of the present embodiment may contain, in addition to the resin component, components derived from additives, such as antifoaming agents, catalysts, foaming agents, foam stabilizers, abrasive grains, dyes, pigments, solid fine particles, flame retardants, hydrophilizing agents, hydrophobicizing agents, light resistance agents, antioxidants, and antistatic agents, which will be described later in the method for producing a lapping pad of the present embodiment.

[0039] [Wrapping pad manufacturing method] The method for producing a lapping pad of this embodiment includes a step of curing a mixed solution of at least one prepolymer and at least two curing agents to obtain a resin sheet having a microphase-separated structure. This method allows the lapping pad of this embodiment to be produced easily. Each step of the method for producing a lapping pad is described in detail below.

[0040] (Mixing process) The method for manufacturing a lapping pad according to the present embodiment may include a mixing step of preparing a mixed solution of at least one prepolymer and at least two curing agents. By using at least two curing agents in the mixing step, a resin sheet having a microphase-separated structure can be obtained in the molding step following the mixing step. In particular, by forming a microphase-separated structure using two or more curing agents, it is easier to control the curing reaction and the shape of the microphase-separated structure than when forming a microphase-separated structure using two or more prepolymers.

[0041] In the mixing step, for example, at least one prepolymer and at least two curing agents heated to 30°C to 90°C are placed in a temperature-adjustable jacketed mixer and stirred at 30°C to 130°C. At this time, the mixed solution may be transferred to a tank with a jacket equipped with a stirrer and aged, if necessary. The stirring time is adjusted appropriately depending on the number of teeth, rotation speed, clearance, etc. of the mixer, but is, for example, 0.1 to 60 seconds.

[0042] (hardening agent) The curing agent used in the mixing step is not particularly limited, but examples thereof include amino group-containing compounds and hydroxyl group-containing compounds. Examples of the amino group-containing compound include, but are not particularly limited to, 4,4'-methylenebis(2-chloroaniline) (MOCA), ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, 4-methyl-2,6-bis(methylthio)-1,3-benzenediamine, 2-methyl-4,6-bis(methylthio)-1,3-benzenediamine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 2,2-bis[3- Examples of the amino group-containing compound include 2,2-bis[3-(1-methylpropylamino)-4-hydroxyphenyl]propane, 2,2-bis[3-(1-methylpentylamino)-4-hydroxyphenyl]propane, 2,2-bis(3,5-diamino-4-hydroxyphenyl)propane, 2,6-diamino-4-methylphenol, trimethylethylenebis-4-aminobenzoate, and polytetramethyleneoxide-di-p-aminobenzoate. The amino group-containing compound is preferably 4,4'-methylenebis(2-chloroaniline).

[0043] The hydroxyl group-containing compound is not particularly limited, but examples thereof include ethylene glycol, propylene glycol, diethylene glycol, trimethylene glycol, tetraethylene glycol, triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 1,2-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol, and tetramethylene glycol. Examples of suitable hydroxyl group-containing compounds include glycol, 3-methyl-4,3-pentanediol, 3-methyl-4,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, trimethylolpropane, trimethylolethane, trimethylolmethane, polytetramethylene glycol, polyethylene glycol, and polypropylene glycol. From the viewpoint of controlling the reaction, it is preferable to use a bifunctional (diol) hydroxyl group-containing compound rather than a trifunctional or higher functional compound. Furthermore, polytetramethylene glycol is more preferred as the hydroxyl group-containing compound.

[0044] The curing agents may be used in combination of two or more. The combination of curing agents is not particularly limited, but the combinations described below are preferred.

[0045] The active hydrogen equivalent (e.g., NH equivalent and OH equivalent) of the curing agent is not particularly limited and may be, for example, 50 to 5,000, 100 to 4,000, or 130 to 3,000. The OH equivalent of a curing agent that is a hydroxyl group-containing compound may be 100 to 5,000, 200 to 4,000, or 300 to 3,000. The NH equivalent of a curing agent that is an amino group-containing compound may be 50 to 2,000, 75 to 1,000, or 100 to 300.

[0046] In the mixing step, at least two curing agents are used. It is preferable to use a combination of curing agents that have low compatibility with each other, and / or different reactivities, and / or different active hydrogen equivalents. This embodiment tends to more reliably obtain a microphase-separated structure. Examples of combinations of curing agents with different reactivities include combinations of curing agents with different active hydrogen groups, and more specifically, combinations of an amino group-containing compound and a hydroxyl group-containing compound.

[0047] When two or more curing agents having the same active hydrogen group are used, that is, when two or more hydroxyl group-containing compounds or two or more amino group-containing compounds are used, the two or more curing agents preferably include two curing agents whose difference in active hydrogen equivalent is 500 or more and 2000 or less. More preferably, the two or more curing agents include a curing agent whose active hydrogen equivalent is 200 or more and 500 or less and a curing agent whose active hydrogen equivalent is 1000 or more and 2000 or less.

[0048] When two or more curing agents having the same active hydrogen group are used, and the two or more curing agents include two curing agents whose difference in active hydrogen equivalent is 500 or more and 2000 or less, the ratio of the amount of the curing agent with the smaller active hydrogen equivalent to the amount of the curing agent with the larger active hydrogen equivalent, in terms of the ratio of the number of active hydrogen groups, "curing agent with the smaller active hydrogen equivalent:curing agent with the larger active hydrogen equivalent," is preferably 1:1 to 1:15, and more preferably 1:1 to 1:10.

[0049] When two or more curing agents having the same active hydrogen group are used, and the two or more curing agents include one curing agent with an active hydrogen equivalent of 200 or more and 500 or less and another curing agent with an active hydrogen equivalent of 1000 or more and 2000 or less, the ratio of the amount of the curing agent with an active hydrogen equivalent of 200 or more and 500 or less to the amount of the curing agent with an active hydrogen equivalent of 1000 or more and 2000 or less, in terms of the number of active hydrogen groups, is preferably 1:1 to 1:15, and more preferably 1:1 to 1:10.

[0050] As a specific preferred combination of curing agents, the at least two curing agents preferably include an amino group-containing compound and a hydroxyl group-containing compound. The at least two curing agents more preferably include one amino group-containing compound and two or more hydroxyl group-containing compounds, or two or more amino group-containing compounds and one hydroxyl group-containing compound. The at least two curing agents even more preferably include one amino group-containing compound and two or more hydroxyl group-containing compounds.

[0051] When the at least two curing agents contain an amino group-containing compound and a hydroxyl group-containing compound, the difference between the NH equivalent of the amino group-containing compound and the OH equivalent of the hydroxyl group-containing compound is not particularly limited, but it is preferable that the OH equivalent of the hydroxyl group-containing compound is larger, and it is more preferable that the OH equivalent of the hydroxyl group-containing compound is larger by 100 or more and 2000 or less than the NH equivalent of the amino group-containing compound.

[0052] When the at least two types of curing agents include an amino group-containing compound and a hydroxyl group-containing compound, the ratio of the amount of the curing agent that is the amino group-containing compound used to the total amount of the curing agents used is preferably 35% or more and 95% or less, and more preferably 40% or more and 90% or less, in terms of the ratio of the number of functional groups.

[0053] An example of a preferred combination of curing agents includes at least two curing agents, a first curing agent (amino group-containing compound) having an NH equivalent of 100 to 300 and a second curing agent (hydroxyl group-containing compound) having an OH equivalent of 1000 to 2000. The ratio of the amount of the first curing agent to the amount of the second curing agent used is not particularly limited, but the amount of the first curing agent used is preferably 35% to 98% in terms of functionality, more preferably 35% to 95%, and even more preferably 40% to 90%. The amount of the second curing agent used is preferably 2% to 60% in terms of functionality, more preferably 3% to 60%, and even more preferably 5% to 50% in terms of functionality, relative to the total amount of curing agents used. The amount of the first curing agent used is preferably 10% to 90% by mass, and more preferably 15% to 80% by mass, of the total amount of curing agents used. The amount of the second curing agent used is preferably 10% to 50% by mass, and more preferably 15% to 40% by mass, of the total amount of curing agents used.

[0054] Generally, the total amount of curing agent used is determined by the R value, which is the equivalent ratio of the active hydrogen groups (amino groups and hydroxyl groups) present in the curing agent when the number of functional groups in the prepolymer is taken as 1. The total amount of curing agent used is preferably adjusted so that the R value is 0.7 or more and 1.3 or less. The R value is more preferably 0.8 or more and 1.2 or less.

[0055] By using the above-mentioned preferred combination of curing agents in appropriate amounts, it is possible to more reliably obtain a pore distribution measured by mercury intrusion porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm, in which the cumulative pore volume V in the pore diameter range of 0.010 μm to 1.0 μm is 0.21 cm 3 / g or more 1.00cm 3 / g or less, and / or a resin sheet having a microphase-separated structure can be obtained. As a combination of curing agents, two or more curing agents having low compatibility with each other, two or more curing agents having different reactivities, and / or curing agents having different active hydrogen equivalents can be used. Even if a resin sheet having a clear microphase-separated structure cannot be obtained by such a combination, a resin sheet having a microphase-separated structure tends to be obtained by adjusting the type of curing agent so that they are mutually compatible, changing the curing agent so that their reactivities are similar, and / or changing the curing agent so that their active hydrogen equivalents are close to each other.

[0056] (prepolymer) The prepolymer used in the mixing step is not particularly limited, but examples thereof include urethane prepolymers. Examples of urethane prepolymers include an adduct of hexamethylene diisocyanate and hexanetriol; an adduct of 2,4-tolylene diisocyanate and prenzcatechol; an adduct of 2,4-tolylene diisocyanate, poly(oxytetramethylene) glycol, and diethylene glycol; an adduct of tolylene diisocyanate and hexanetriol; an adduct of tolylene diisocyanate and trimethylolpropane; an adduct of xylylene diisocyanate and trimethylolpropane; an adduct of hexamethylene diisocyanate and trimethylolpropane; and an adduct of isocyanuric acid and hexamethylene diisocyanate. Other isocyanate group-containing compounds prepared by reacting a polyisocyanate compound with a polyol compound, as well as various commercially available urethane prepolymers, may also be used.

[0057] The polyisocyanate compound used in preparing the isocyanate group-containing compound is not particularly limited as long as it has two or more isocyanate groups in the molecule. For example, diisocyanate compounds having two isocyanate groups in the molecule include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate (2,6-TDI), 2,4-tolylene diisocyanate (2,4-TDI), naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate (MDI), 4,4'-methylene-bis(cyclohexyl isocyanate) (hydrogenated MDI), 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'-dimethyl ... Examples of the isocyanate include ethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, p-phenylene diisothiocyanate, xylylene-1,4-diisothiocyanate, and ethylidine diisothiocyanate.

[0058] These polyisocyanate compounds may be used alone or in combination of two or more. As the polyisocyanate compound, a diisocyanate compound is preferred, and 2,4-TDI, 2,6-TDI, and MDI are more preferred.

[0059] Examples of polyol compounds used in preparing isocyanate group-containing compounds include diol compounds and triol compounds such as ethylene glycol, diethylene glycol (DEG), and butylene glycol; polyether polyol compounds such as polypropylene glycol (PPG) and poly(oxytetramethylene) glycol (PTMG); polyester polyol compounds such as the reaction product of ethylene glycol and adipic acid or the reaction product of butylene glycol and adipic acid; polycarbonate polyol compounds, and polycaprolactone polyol compounds. Trifunctional propylene glycol with added ethylene oxide can also be used. Polyol compounds may be used alone or in combination of two or more.

[0060] The NCO equivalent of the urethane prepolymer is preferably 150 or more and 700 or less, more preferably 200 or more and 600 or less, and even more preferably 200 or more and 500 or less. The "NCO equivalent" is a numerical value indicating the molecular weight of the urethane prepolymer per NCO group, calculated by (parts by mass of polyisocyanate compound + parts by mass of polyol compound) / [(number of functional groups per molecule of polyisocyanate compound × parts by mass of polyisocyanate compound / molecular weight of polyisocyanate compound) - (number of functional groups per molecule of polyol compound × parts by mass of polyol compound / molecular weight of polyol compound)].

[0061] In the mixing step, at least one prepolymer is used. Two or more of the above prepolymers may be used in combination, but preferably one prepolymer is used alone. According to such an embodiment, the curing reaction tends to be easily controlled, and the shape of the microphase-separated structure tends to be easily controlled. As the prepolymer, it is preferable to use a urethane prepolymer containing tolylene diisocyanate as the main component alone.

[0062] The amount of prepolymer used is not particularly limited, but is preferably 30 parts by mass or more and 80 parts by mass or less, and more preferably 40 parts by mass or more and 75 parts by mass or less, based on the total amount of the mixed liquid.

[0063] (additives) In the mixing step, components other than the prepolymer and the curing agent may be mixed as additives. Examples of additives include solvents (diluents) such as polypropylene glycol; antifoaming agents such as silicone-based antifoaming agents; catalysts; foaming agents such as water and hollow fine particles; foam stabilizers such as silicone-based foam stabilizers; and fillers (abrasive grains) such as cerium oxide; dyes; pigments; solid fine particles; flame retardants; hydrophilizing agents; hydrophobic agents; light-resistant agents; antioxidants; and antistatic agents. The density of the resulting resin sheet is 0.3 g / cm. 3 More than 0.9g / cm 3 From the viewpoints below, it is preferable to add a foaming agent to adjust the density, and it is more preferable to adjust the amount of foaming agent added.

[0064] In the mixing step, by adjusting the type and amount of catalyst added, the reaction rate of the curing reaction can be controlled, and the microphase-separated structure formed can be controlled.

[0065] (molding process) The molding step is a step of obtaining a resin sheet having a microphase-separated structure by curing the mixed liquid obtained as described above. In the molding step, for example, the mixed liquid obtained in the mixing step is poured into a mold preheated to 30°C to 150°C and heated at about 30°C to 150°C for about 10 minutes to 5 hours. This causes the prepolymer and the curing agent to react to form a resin, thereby curing the mixed liquid. Furthermore, secondary curing may be performed by further heating in an oven at about 50°C to 180°C for about 10 minutes to 10 hours. In the method for producing a wrapping pad according to this embodiment, since the mixed liquid is the above-described liquid, a resin block having a microphase-separated structure can be obtained.

[0066] The reaction temperature when curing the mixed solution in the molding step can be adjusted appropriately depending on the types and compounding ratios of the prepolymer, curing agent, and additives used, and adjusting the reaction temperature tends to control the reaction rate of the curing reaction and the microphase-separated structure that is formed.

[0067] In the molding process, a resin sheet having a microphase-separated structure is obtained by cutting a resin sheet of an appropriate thickness from the resin block obtained as described above. The obtained resin sheet may be aged at 30°C to 150°C for about 1 hour to 24 hours.

[0068] The resin sheet thus obtained has a double-sided tape attached to one side thereof, and is then cut into a predetermined shape, preferably a disk, to complete the wrapping pad of this embodiment. The double-sided tape is not particularly limited, and any double-sided tape known in the art can be selected and used.

[0069] The wrapping pad of this embodiment may have a single-layer structure consisting of only a resin sheet, or may have a multi-layer structure in which another layer (a cushion layer or a substrate layer) is attached to one side of the resin sheet. In the case of a multi-layer structure, the layers may be bonded and fixed together using double-sided tape or an adhesive, while applying pressure as necessary. The double-sided tape and adhesive used are not particularly limited, and may be selected from conventionally known double-sided tapes and adhesives.

[0070] Furthermore, the wrapping pad of this embodiment may have grooves, embossing, and / or holes (punching) on ​​the surface, as needed. The shape of the grooves and embossing is not particularly limited, and examples thereof include a lattice shape, a concentric circle shape, and a radial shape.

[0071] The lapping pad may be dressed (grinded) on the front and / or back surfaces of the resin sheet. The resin sheet in the method for producing a lapping pad of this embodiment has high density but has interconnected pores, so it has excellent dressability and can be dressed under easy conditions. The dressing method is not particularly limited, and can be performed by a known method such as grinding with a diamond dresser.

[0072] [Method of manufacturing lapped products] The method for producing a lapped product of this embodiment includes a lapping step in which a workpiece is lapped using the lapping pad in the presence of a slurry to obtain a lapped product.

[0073] In the method for manufacturing a lapped product according to this embodiment, the workpiece is pressed against the lapping pad by the holding platen while the holding platen and the lapping platen are rotated relative to each other while supplying the slurry. The workpiece surface is lapped by the action of the lapping pad. The holding platen and the lapping platen may rotate in the same direction at different rotational speeds, or in opposite directions. Furthermore, the workpiece may be lapped while moving (rotating) inside the frame during the lapping process.

[0074] The slurry may contain liquid components such as water and oil, additives, and abrasive grains (polishing particles; for example, diamond, SiC, B4C, and Al2O3), depending on the workpiece and lapping conditions.

[0075] The workpiece is not particularly limited, but examples thereof include optical materials such as lenses, plane-parallel plates, and reflective mirrors, semiconductor wafer materials such as SiC disks, crystals, metals, stone, wood, resin materials, and ceramics. [Example]

[0076] The present embodiment will be described in more detail below using examples and comparative examples, but the present embodiment is not limited to the following examples.

[0077] [Measurement of cumulative pore volume (pore distribution) by mercury intrusion method] The cumulative pore volume (pore distribution) of the resin sheet was measured by mercury intrusion porosimetry. A 10 mm square sample was cut from a 2 mm thick resin sheet and used for the measurement. The cumulative pore volume was measured using a Micromeritics Auto Pore III under conditions of a contact angle of 130° and a mercury surface tension of 485 dyn / cm. The cumulative pore volume was calculated for pores with diameters ranging from 360 μm to 0.005 μm by sweeping the mercury pressure from 0.5 psia to 30,000 psia. The pore distribution was calculated using data processing software for porosimetry (Shimadzu Corporation, product name POREPLOT-PCW). The pore distribution for each measurement result is shown for pores with diameters ranging from 360 μm to 0.010 μm.

[0078] [Observation of resin sheet] Whether or not the resin sheet has a microphase-separated structure was confirmed by observation with a scanning electron microscope (SEM) at a magnification of about 300 to 3000 times.

[0079] [Measurement of average pore size] A 1.3mm square area on the surface of the lapping pad was observed at 175x magnification using a microscope (VH-6300, manufactured by KEYENCE), and the resulting image was binarized using image processing software (Image Analyzer V20LAB Ver.1.3, manufactured by Nikon) to confirm the number of bubbles. The equivalent circle diameter was calculated from the area of ​​each pore, and the average of these was taken as the average pore diameter (μm). The cutoff value (lower limit) for the pore diameter was set to 10μm, and the average pore diameter was obtained as the average of pore diameters of 10μm or more.

[0080] [Example 1] A urethane prepolymer with an NCO equivalent of 407, primarily composed of 2,4-tolylene diisocyanate (TDI), was prepared. 61.83 parts by weight of this urethane prepolymer was mixed with 15.18 parts by weight of 4,4'-methylenebis(2-chloroaniline) (MOCA) (NH2 equivalent: 134) and 5.65 parts by weight of polypropylene glycol (OH equivalent: 1345). 0.15 parts by weight of a silicone foam stabilizer (Dow Corning Toray Co., Ltd., product name "SH193"), 0.03 parts by weight of a catalyst (Tosoh Corporation, product name "Toyocat ET"), 0.16 parts by weight of water as a foaming agent, and 17 parts by weight of calcium carbonate filler as an abrasive, to obtain a mixture that would serve as a precursor to the resin sheet. The R value of the mixture was 0.9.

[0081] The resulting mixture was poured into a mold preheated to 50°C and subjected to a primary cure at 50°C for 15 minutes. The resulting block-shaped molded product was removed from the mold and subjected to a secondary cure at 120°C for 8 hours in an oven to obtain a urethane resin block. The resulting urethane resin block was allowed to cool to 25°C and then sliced ​​to obtain a 2.0 mm thick resin sheet.

[0082] The density was calculated from the volume and weight of the sample cut out from the resin sheet, and the density of the obtained resin sheet was 0.55 g / cm 3 The measurement results of the pore size distribution are shown in Figure 1. Table 1 also shows the cumulative pore volume V in the pore size range of 0.010 μm to 1.0 μm, the cumulative pore volume V0 in the pore size range of 0.010 μm to 360 μm, the ratio V / V0, the average pore size, and the peak position of the maximum peak in the pore size range of 0.010 μm to 360 μm, all of which were determined from the pore size distribution.

[0083] Furthermore, when the surface of the resin sheet was observed with a scanning electron microscope, it was confirmed that it had a microphase-separated structure (three-dimensional network structure). Examples of SEM images are shown in Figure 2 (500x magnification) and Figure 3(A) (2000x magnification). As shown by the dashed line in Figure 3(B), it was confirmed that the resin sheet had an amorphous void cross section and a resin skeleton / resin skeleton cross section, particularly in the upper left part of the figure. Therefore, it was evaluated as having at least a single gyroid structure.

[0084] [Example 2] A urethane prepolymer with an NCO equivalent of 382, ​​primarily composed of 2,4-tolylene diisocyanate (TDI), was prepared. 55.26 parts by weight of this urethane prepolymer was mixed with 15.27 parts by weight of 4,4'-methylenebis(2-chloroaniline) (MOCA) (NH2 equivalent: 134), 7.04 parts by weight of polytetramethylene glycol (OH equivalent: 972), and 4.24 parts by weight of polypropylene glycol (OH equivalent: 1345). To this mixture, 0.11 parts by weight of a silicone foam stabilizer (Dow Corning Toray Co., Ltd., product name "SH193"), 0.03 parts by weight of a catalyst (Tosoh Corporation, product name "Toyocat ET"), 0.05 parts by weight of water as a foaming agent, and 18 parts by weight of calcium carbonate filler as an abrasive were further added to obtain a mixture that would serve as a resin sheet precursor. The R value of the mixture was 0.9.

[0085] The resulting mixture was poured into a mold preheated to 50°C and subjected to a primary cure at 50°C for 15 minutes. The resulting block-shaped molded product was removed from the mold and subjected to a secondary cure at 120°C for 8 hours in an oven to obtain a urethane resin block. The resulting urethane resin block was allowed to cool to 25°C and then sliced ​​to obtain a 2.0 mm thick resin sheet.

[0086] The density was calculated from the volume and weight of the sample cut out from the resin sheet, and the density of the obtained resin sheet was 0.89 g / cm 3The measurement results of the pore size distribution are shown in Figure 4. Table 1 also shows the cumulative pore volume V in the pore size range of 0.010 μm to 1.0 μm, the cumulative pore volume V0 in the pore size range of 0.010 μm to 360 μm, the ratio V / V0, the average pore size, and the peak position of the maximum peak in the pore size range of 0.010 μm to 360 μm, all of which were determined from the pore size distribution. Figure 5 shows an example of an SEM image.

[0087] [Comparative Example 1] 61.59 parts by weight of the same urethane prepolymer as in Example 1 was mixed with 9.24 parts by weight of 4,4'-methylenebis(2-chloroaniline) (MOCA) (NH2 equivalent: 134) and 9.24 parts by weight of crude MOCA (NH2 equivalent: 189). To this mixture, 0.18 parts by weight of a silicone foam stabilizer (manufactured by Dow Corning Toray Co., Ltd., product name "SH193"), 2.58 parts by weight of a polyether (OH equivalent: 1007) as a diluent, 0.04 parts by weight of a catalyst (manufactured by Tosoh Corporation, product name "Toyocat ET"), 0.13 parts by weight of water as a foaming agent, and 17 parts by weight of calcium carbonate filler as an abrasive were further added to obtain a mixture that would serve as a resin sheet precursor. The R value of the mixture was 0.9.

[0088] The resulting mixture was poured into a mold preheated to 50°C and subjected to a primary cure at 50°C for 15 minutes. The resulting block-shaped molded product was removed from the mold and subjected to a secondary cure at 120°C for 8 hours in an oven to obtain a urethane resin block. The resulting urethane resin block was allowed to cool to 25°C and then sliced ​​to obtain a 2.0 mm thick resin sheet.

[0089] The density was calculated from the volume and weight of the sample cut out from the resin sheet, and the density of the obtained resin sheet was 0.53 g / cm 3 The measurement results of the pore size distribution are shown in Figure 6. Table 1 also shows the cumulative pore volume V in the pore size range of 0.010 μm to 1.0 μm, the cumulative pore volume V0 in the pore size range of 0.010 μm to 360 μm, the ratio V / V0, the average pore size, and the peak position of the maximum peak in the pore size range of 0.010 μm to 360 μm, all of which were determined from the pore size distribution.

[0090] Furthermore, when the surface of the resin sheet of Comparative Example 1 was observed with a scanning electron microscope, no microphase-separated structure was confirmed. An example of an SEM image is shown in Fig. 7. In Comparative Example 1, it is believed that the desired curing reaction did not proceed due to at least an insufficient amount of curing agent having an OH equivalent of 1000 or more and 2000 or less, and therefore microphase separation did not occur.

[0091] [Table 1]

[0092] In Example 1, the position of the maximum peak in the range of 1.0 μm or more and 360 μm or less is 129 μm, and its height is 0.40 cm 3 The maximum peak in the pore diameter range of 0.010 μm to 360 μm was at 0.0822 μm and its height was 1.65 cm. 3 / g. From the above measurement results, it was confirmed that the resin sheet of Example 1 contains both voids derived from the foaming agent and voids derived from the microphase separation structure, and that the latter voids are interconnected throughout the entire wrapping pad.

[0093] In Example 2, the position of the maximum peak in the range of 1.0 μm to 360 μm is 77 μm, and its height is 0.075 cm 3 The maximum peak position in the pore diameter range of 0.010 μm to 360 μm was 0.0411 μm, and its height was 0.447 cm 3 / g. From the above measurement results, it was confirmed that the resin sheet of Example 2 contains both voids derived from the foaming agent and voids derived from the microphase separation structure, and that the latter voids are interconnected throughout the entire wrapping pad.

[0094] A lapping test and an evaluation test of affinity with a slurry were conducted using the lapping pads of Examples 1 and 2. As a control, a lapping test and an evaluation test of affinity with a slurry were conducted under the same conditions using the lapping pad of Comparative Example 1. As a result, it was found that the lapping pads of the Examples can impart good flatness to the workpiece and have excellent affinity with a slurry compared to the lapping pad of Comparative Example. [Industrial Applicability]

[0095] The lapping pad of the present invention has industrial applicability as a lapping pad used for lapping optical materials such as lenses, plane-parallel plates, and reflective mirrors, semiconductor wafer materials such as SiC disks, crystals, metals, stone, wood, resin materials, and ceramics.

Claims

1. A wrapping pad comprising a resin sheet having fine holes, In the pore distribution of the resin sheet measured by mercury intrusion porosimetry with a contact angle of 130° and a mercury surface tension of 485 dyn / cm, the cumulative pore volume V in the pore diameter range of 0.010 μm or more and 1.0 μm or less was 0.21 cm 3 / g or more 1.00cm 3 / g or less, The density of the resin sheet is 0.3 g / cm 3 0.9g / cm or more 3 Below is the wrapping pad.

2. In the pore distribution of the resin sheet, the cumulative pore volume V in the pore diameter range of 0.010 μm or more and 360 μm or less 0 2. The lapping pad according to claim 1, wherein the ratio of the cumulative pore volume V to the cumulative pore volume V is 50% or more.

3. 3. The wrapping pad according to claim 1, wherein an average pore diameter measured for pores of 10 μm or more in the resin sheet is 50 μm or more and 200 μm or less.

4. In the pore distribution of the resin sheet, the peak position of the maximum peak in the pore diameter range of 0.010 μm or more and 360 μm or less is within the pore diameter range of 0.010 μm or more and 1.0 μm or less. The lapping pad according to any one of claims 1 to 3.

5. The wrapping pad according to any one of claims 1 to 4, wherein the resin sheet has a microphase separation structure.

6. The wrapping pad according to any one of claims 1 to 5, wherein the resin sheet contains polyurethane.

7. A method for producing the lapping pad according to any one of claims 1 to 6, comprising the steps of: A method for producing a lapping pad, comprising a step of curing a mixed liquid of at least one prepolymer and at least two curing agents to obtain a resin sheet having a microphase-separated structure.

8. The curing agent is NH 2 8. The method of claim 7, comprising a first curing agent having an equivalent weight of 100 or more and 300 or less, and a second curing agent having an OH equivalent weight of 1000 or more and 2000 or less.

9. A method for producing a lapped product, comprising a lapping step of lapping a workpiece using the lapping pad according to any one of claims 1 to 6 in the presence of a slurry.

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