Substrate-less abrasive material and method for manufacturing the same

Abstract

The present invention employs a configuration without a base material, and provides a base material-less abrasive material that flexibly deforms to conform to the surface of the object to be polished, especially if the surface has a curved shape, and has good polishing characteristics. The substrate-less abrasive material 1 of the present invention does not have a substrate, and a plurality of abrasive grains 2 are held in a dispersed state in a base portion 3 which contains a total of 60 volume% or more of at least one of the base components of resin and elastomer. The type A durometer hardness measured in accordance with the hardness test specified in JIS K7311-1995 is 50 to 80, the tensile strength is 70 to 250 MPa, and the tensile elongation is 10 to 360%.

Description

Technical Field

[0001] The present invention relates to a substrate-free abrasive and a method for producing the same.

Background Art

[0002] As shown in FIG. 7, a conventional abrasive 100 includes a substrate 104 made of a sheet-like material such as paper, cloth, film, or non-woven fabric, and a plurality of abrasive grains (abrasive particles) 102 that are adhesively fixed via an adhesive 103 in a state of being dispersed on the surface of the substrate 104.

[0003] Generally, the reason a substrate is required for an abrasive is to fix the abrasive grains. By fixing the abrasive grains to the substrate, their shape (posture) is maintained, making them easier to handle. Additionally, compared to free abrasive grains, faster polishing becomes possible.

[0004] However, an abrasive 100 having a substrate 104 has problems such as not conforming to the surface irregularities of the surface to be polished of the object to be polished when using a hard substrate, resulting in over-scratching or accidental scratches. Also, when using a soft substrate, wrinkles are likely to occur in the abrasive during manufacturing or polishing, making it difficult to achieve uniform polishing and increasing the defect rate.

[0005] In particular, in the manufacture of automobiles, there is a process of polishing a coating film formed on the outer surface (surface to be polished) of the outer panel of an automobile body. However, the automobile body is formed in a curved shape called an R surface or an inverse R surface rather than a flat surface.

[0006] When polishing such a curved surface to be polished using an abrasive 100 having a substrate 104, although an operator tries to suppress polishing unevenness by using a urethane foam cushioning material between the abrasive and a support (such as a sander or a file), or by using a flexible substrate such as a sponge pad like the polishing sheet described in Patent Document 1, sufficient polishing performance has not been obtained at present.

[0007] Furthermore, such conventional abrasives 100 have a laminated structure in which an abrasive layer 105 composed of abrasive grains and adhesive 103 is bonded and fixed to the surface of a base material 104. Because an adhesive interface exists between the base material 104 and the abrasive layer 105, there is a risk that the abrasive layer 105 may peel off from the base material 104 at the adhesive interface during polishing. If the abrasive layer 105 peels off, the abrasive material's original polishing properties cannot be obtained.

[0008] Furthermore, the thickness ratio of the base material 104 to the abrasive material 100 is usually around 30-40%, and in the state of used abrasive material that is disposed of after abrasive use, the abrasive layer 105 is considerably worn down, so the thickness ratio of the base material to the used abrasive material is expected to be even higher, at 50% or more. In particular, the use of abrasive material 100 that uses a film or sheet made of plastic such as PET as the base material 104 is undesirable because it leads to an increase in the amount of waste.

[0009] Therefore, it is desirable to use a so-called base material-less abrasive material that does not use base material 104 as the abrasive material.

[0010] Conventional substrate-less abrasives include, for example, a polishing film made of a cured product of a resin composition containing epoxy resin (A), a curing accelerator (B), and abrasive particles (C), as described in Patent Document 2.

[0011] However, the polishing film described in Patent Document 2 uses epoxy resin, a relatively hard resin, as the resin constituting the base portion. Therefore, it does not anticipate cases where the surface to be polished has a curved shape, such as the outer panel of an automobile body, or a complex uneven curved shape called an R surface or reverse R surface. As a result, the polishing film cannot flexibly deform to follow the curved shape of the surface to be polished during polishing. Consequently, with the polishing film described in Patent Document 2, for example, when polishing a painted surface (coating) formed on the curved surface of an automobile's outer panel, there is a problem that the coating is partially and excessively removed, making uniform polishing impossible. In addition, when manufacturing a polishing film using epoxy resin with a film manufacturing apparatus (die coater) using a role-to-role type carrier film, the hardness of the polishing film leads to problems such as poor workability, difficulty in handling, and impracticality.

[0012] Furthermore, while conventional abrasives exist that use a soft urethane resin as a base material, which has low bending rigidity, these abrasives, although capable of flexibly deforming to conform to the curved shape of the surface to be polished, are too flexible as a whole and cannot maintain their shape, and have low tensile strength, resulting in problems in obtaining good polishing properties. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Japanese Patent Application Publication No. 9-123065 [Patent Document 2] Japanese Patent Publication No. 2023-28400 [Overview of the project] [Problems that the invention aims to solve]

[0014] The object of the present invention is to provide a substrate-less abrasive material and a method for manufacturing the same, which employs a configuration without a base material and flexibly deforms to conform to the surface of the workpiece, even if the surface of the workpiece has a curved shape or a complex uneven curved shape, thereby having good polishing characteristics. [Means for solving the problem]

[0015] To solve the above problems, the characteristic configuration of the present invention is as follows.

[0016] (1) A sheet-like substrate-less abrasive material comprising a base portion containing a total of 60% or more by volume of at least one of the base components of resin and elastomer, wherein a plurality of abrasive grains are held in a dispersed state in a base portion without a substrate, and the substrate-less abrasive material has a Type A durometer hardness of 50 to 80, a tensile strength of 70 to 250 MPa, and a tensile elongation of 10 to 360% when measured in accordance with the hardness test specified in JIS K7311-1995. (2) The base material-less abrasive material according to (1) above, wherein the base component of the base portion is urethane resin. (3) The base portion is composed of two layers, a lower base layer and an upper base layer, wherein the base component of the lower base layer is urethane resin and the base component of the upper base layer is soft epoxy resin, as described in (1) above. (4) The base material-less abrasive material according to (3) above, wherein the ratio of the thickness of the lower base layer to the thickness of the upper base layer is in the range of 30:1 to 2:1. (5) The base portion further contains a filler having the property of increasing the tensile strength and decreasing the tensile elongation of the base material-less abrasive material according to any one of (1) to (4) above. (6) A method for manufacturing the substrate-less abrasive according to any one of (1) to (5) above, comprising: applying a first adhesive containing at least one base component of resin and elastomer on the surface of a support having peelability to form a first adhesive layer; attaching a plurality of abrasive grains in a dispersed state to the first adhesive layer; applying a second adhesive having the same or different composition as the first adhesive on the first adhesive layer having the plurality of abrasive grains attached in a dispersed state to form a second adhesive layer, thereby forming a first composite film corresponding to a sheet-like substrate-less abrasive on the surface of the support; and peeling the first composite film from the support to obtain the substrate-less abrasive.

Effect of the Invention

[0017] According to the present invention, a configuration without a substrate is adopted, and even when the surface to be polished of the workpiece to be polished has a particularly curved surface shape or a surface with a complex uneven shape, it can be flexibly deformed to follow the surface to be polished, and a substrate-less abrasive having good polishing characteristics and a method for manufacturing the same can be provided.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a substrate-less abrasive according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a substrate-less abrasive according to a second embodiment. [Figure 3] FIG. 3 is a cross-sectional view schematically showing a substrate-less abrasive according to a third embodiment. [Figure 4] FIG. 4 is a cross-sectional view schematically showing a substrate-less abrasive according to a fourth embodiment. [Figure 5] FIG. 5 is a cross-sectional view schematically showing a substrate-less abrasive according to a fifth embodiment. [Figure 6] FIG. 6 is a diagram for explaining each step of the method for manufacturing the substrate-less abrasive shown in FIG. 1. [Figure 7] FIG. 7 is a cross-sectional view schematically showing a conventional abrasive.

Embodiments for Carrying Out the Invention

[0019] Next, several embodiments according to the present invention will be described in detail below. (1) First Embodiment The substrate - free abrasive of the first embodiment is a sheet - shaped substrate - free abrasive in which a plurality of abrasive grains are held in a dispersed state in a base portion containing at least 60% by volume in total of at least one of resin and elastomer as base components, and the substrate - free abrasive has a Type A durometer hardness of 50 - 80, a tensile strength of 70 - 250 MPa, and a tensile elongation of 10 - 360% when measured in accordance with the hardness test defined in JIS K7311 - 1995.

[0020] <Substrate - free abrasive> FIG. 1 schematically shows the substrate - free abrasive according to the first embodiment. The illustrated substrate - free abrasive 1 is mainly composed of a plurality of abrasive grains 2 and a base portion 3 without a substrate. More specifically, it is formed as a composite film in which at least a part of the abrasive grains 2 are embedded in a base portion 3 having at least one of resin and elastomer as a main component (containing 60% by volume or more in total). Here, the "composite film" means a sheet or film that does not have a material (substrate) to support it.

[0021] <Abrasive grains>[ As shown in FIG. 1, the plurality of abrasive grains 2 are held in a dispersed state in the base portion 3. A part of the abrasive grains 2 is exposed on the film surface to function as an abrasive material. Examples of the material of the abrasive grains 2 include inorganic materials such as alumina (Al2O3), silicon carbide (SiC), cubic boron nitride (cBN), diamond, emery, silica (SiO2), zirconia (ZrO2), and glass, but it is not particularly limited.

[0022] The average particle size of the abrasive grains 2 is preferably in the range of 0.1 to 125 μm, and more preferably in the range of 3 to 100 μm. If the average particle size is larger than 125 μm, it will result in hard, coarse polishing, and sufficient polishing performance may not be ensured without a base material. Also, if the abrasive grains are smaller than 0.1 μm, handling during the manufacturing of the abrasive material may become difficult. The particle size of the abrasive grains can be measured by laser diffraction or the Coulter method (electrical detection band method).

[0023] The material and particle size of the abrasive grains 2 are appropriately selected according to the material of the workpiece (object to be polished) and the required finishing accuracy. In this case, the particle size of the abrasive grains 2 is preferably within the range of -10 to +10% of the selected average particle size, and more preferably within the range of -5 to +5%. Using abrasive grains 2 with a uniform particle size allows for uniform polishing performance.

[0024] Furthermore, the content of abrasive grains 2 in the abrasive material 1 is preferably in the range of 1 to 70 volume%, and more preferably in the range of 10 to 50 volume%. The content of abrasive grains 2 is adjusted to an appropriate level depending on its average particle size and the thickness of the abrasive material.

[0025] <Base section> The base portion 3 is a sheet-like member that contains a total of 60% or more of at least one of the base components, resin and elastomer, and holds a plurality of abrasive grains 2 in a dispersed state.

[0026] [Base ingredients] The base component is at least one component of either a resin or an elastomer.

[0027] Examples of resins include urethane resins, silicone resins, polyester resins, polyol resins, and epoxy resins (limited to soft types). Examples of elastomers include polyurethane and polyester thermoplastic elastomers.

[0028] The base component is preferably a urethane-based resin, and more preferably a polyester-based urethane resin, from the viewpoint of handling during manufacturing.

[0029] • Urethane resin In the urethane resin used in this invention, an isocyanate-based crosslinking agent is preferably used.

[0030] [Mechanical properties of abrasives] The substrate-less abrasive material of this embodiment has mechanical properties such as a Type A durometer hardness of 50 to 80, a tensile strength of 70 to 250 MPa, and a tensile elongation of 10 to 360%, as measured in accordance with the hardness test specified in JIS K7311-1995.

[0031] (I) Durometer hardness The base material-less abrasive of this embodiment has a Type A durometer hardness of 50 to 80 when measured in accordance with the durometer hardness test method specified in JIS K7215-1986. If the Type A durometer hardness is less than 50, the abrasive is too soft, and good polishing performance cannot be obtained even when performing polishing work aimed at flattening the coating film, such as deburring or surface preparation. If the Type A durometer hardness exceeds 80, the abrasive becomes too hard and cannot deform to follow the curved shape of the surface to be polished. The durometer hardness of the base material-less abrasive can be measured by stacking, for example, 20 mm x 20 mm test pieces to a thickness of 2.5 mm or more, and slowly pressing a durometer (model number: GS-706N (manufactured by Teclock Co., Ltd.)) so that the indenter is perpendicular to the measurement surface.

[0032] (II) Tensile strength The substrate-less abrasive material of this embodiment has a tensile strength of 70 to 250 MPa. If the tensile strength is less than 70 MPa, there is insufficient force to fix the abrasive grains during polishing, making it impossible to suppress the (relative) movement of the abrasive grains 2 relative to the base portion 3 that constitutes the abrasive material 1, and thus good polishing performance cannot be achieved. Also, if the tensile strength exceeds 250 MPa, the flexibility of the abrasive material is impaired, making it prone to tearing and breakage. The method for measuring the tensile strength of a base material-less abrasive material is to cut the prepared base material-less abrasive material into a 25 mm x 150 mm test piece, and using a Tensilon universal testing machine RTG-1225 (manufactured by A&D Co., Ltd.), pull the test piece in the longitudinal direction under the conditions of a chuck distance of 100 mm and a tensile speed of 200 mm / min, and measure the maximum point load at that time as the tensile strength (MPa).

[0033] (III) Tensile elongation The substrate-less abrasive material of this embodiment has a tensile elongation of 10 to 360%. If the tensile elongation is less than 10%, tearing and breakage are more likely to occur. Also, if the tensile elongation exceeds 360%, there is insufficient force to fix the abrasive grains during polishing, and the (relative) movement of the abrasive grains relative to the base cannot be suppressed, resulting in poor polishing performance. The method for measuring the tensile elongation of a substrate-less abrasive is to cut the prepared substrate-less abrasive into a 25mm x 150mm test piece, and then pull the test piece in the longitudinal direction using a Tensilon universal testing machine RTG-1225 (manufactured by A&D Co., Ltd.) with a chuck distance of 100mm and a tensile speed of 200mm / min, and measure the maximum elongation at that time as the tensile elongation (%).

[0034] (2) Second embodiment A substrate-less abrasive material according to a second embodiment will be described. Figure 2 schematically shows a substrate-less abrasive material according to the second embodiment. The base material-less abrasive material 1A shown in the figure has the same basic structure as the abrasive material 1 according to the first embodiment, the only difference being that the base portion 3A is composed of two layers: a lower base layer 3a and an upper base layer 3b. The base portion 3A may consist of a lower base layer 3a and an upper base layer 3b made of the same composition, or they may be made of different compositions. The ratio of the thickness of the lower base layer 3a to the upper base layer 3b of the base portion 3A is preferably in the range of 30:1 to 2:1. For example, the lower base layer 3a of the base portion 3A may be made of a urethane resin, and the upper base layer 3b may be made of a resin that firmly fixes abrasive grains, such as a soft epoxy resin (Type A durometer hardness: 70 to 80).

[0035] (3) Third Embodiment A third embodiment of a substrate-less abrasive material will be described. Figure 3 schematically shows a substrate-less abrasive material according to the third embodiment. The base material-less abrasive material 1B shown in the figure has the same basic structure as the abrasive material 1 according to the first embodiment, the difference being that the base portion 3 further contains a filler 4 which has the properties of increasing the tensile strength and decreasing the tensile elongation of the base material-less abrasive material. The substrate-less abrasive material 1B containing filler 4 is preferable to the substrate-less abrasive material 1 that does not contain filler 4 because its tensile strength is 5 to 160 MPa higher and its tensile elongation is 30 to 90% lower, which allows for a better balance between good polishing performance and conformability.

[0036] By further incorporating filler 4 into the base portion 3, the flexibility of the base portion can be maintained while suppressing the movement of abrasive grains in the base portion 3 during polishing, thereby improving polishing performance.

[0037] The filler 4 can be any material that has the property of increasing the tensile strength without significantly reducing the flexibility of the abrasive material 1, or more precisely, the base portion 3, and suppressing (fixing) the movement of abrasive grains 2 in the base portion 3 during polishing. There are no particular limitations, but examples include calcium carbonate (CaCO3), titanium dioxide (TiO2), potassium titanate, and wollastonite.

[0038] The filler 4 preferably has an average particle size in the range of 0.1 μm to 100 μm, and an aspect ratio in the range of 1.0 to 40, which more effectively suppresses the movement of abrasive grains in the base portion 3 during polishing and improves polishing performance.

[0039] The proportion of filler 4 in the base portion 3 is preferably in the range of 1 to 40 volume%, and more preferably in the range of 10 to 25 volume%. If the proportion of filler 4 is less than 1 volume%, the effect of suppressing the movement of abrasive grains in the base portion 3 during polishing cannot be sufficiently obtained, and it is necessary to adjust the physical properties of the resin or elastomer base component itself, which is a component other than the filler that makes up the base portion, so that the physical properties such as hardness, tensile strength, and tensile elongation are within the range of the present invention. Furthermore, if it exceeds 40 volume%, the entire base portion 3 tends to become too hard, making it unsuitable for polishing curved surfaces.

[0040] (4) Fourth Embodiment A substrate-less abrasive material according to a fourth embodiment will be described. Figure 4 schematically shows a substrate-less abrasive material according to the fourth embodiment. The illustrated substrate-less abrasive material 1C has the same basic structure as the abrasive material 1 according to the first embodiment, the difference being that the base portion 3C is composed of two layers, a lower base layer 3c and an upper base layer 3d, and that the lower base layer 3c constituting the base portion 3 further contains a filler 4. The base portion 3C may have the same composition for the base component 5 of the lower base layer 3c and the upper base layer 3d, or it may have different compositions. The ratio of the thickness of the lower base layer 3a and the upper base layer 3b of the base portion 3C is preferably in the range of 30:1 to 2:1. For example, the base portion 3A may have the lower base layer 3a made of a urethane resin and the upper base layer 3b made of a resin that firmly fixes abrasive grains, such as a soft epoxy resin (Type A durometer hardness: 70 to 80).

[0041] (5) Fifth embodiment A substrate-less abrasive material according to a fifth embodiment will be described. Figure 5 schematically shows a substrate-less abrasive material according to the fifth embodiment. The base material-less abrasive material 1D shown in the figure has the same basic structure as the abrasive material 1 according to the first embodiment, the difference being that the abrasive grains 2D are distributed in multiple layers within the base portion 3D.

[0042] Furthermore, the substrate-less abrasive material according to the fourth embodiment can be manufactured, for example, by mixing a plurality of abrasive grains into a solution containing at least one base component of resin and elastomer and a crosslinking agent to prepare a mixed solution, applying this mixed solution to the surface of a releaseable support (release sheet), drying it to form a second composite film corresponding to a sheet-like substrate-less abrasive material which is a coating film, and then peeling the second composite film from the release sheet.

[0043] (6) Other embodiments The substrate-less abrasive material of this embodiment can also be coated with an anti-clogging agent or bonded with loop material in other forms. In a preferred embodiment, the abrasive material of this embodiment can further form a base portion by forming an anti-clogging layer on top of a layer of a base component made of a highly flexible resin. Here, the "anti-clogging layer" refers to a layer that has the function of making it difficult for shavings generated during polishing to enter the space between the abrasive materials and cause the so-called "clogging phenomenon" that hinders polishing. As long as the anti-clogging layer has such a function, there are no particular restrictions on the material, but mainly aliphatic metal salts such as calcium stearate and zinc stearate can be used. The anti-clogging layer can be formed on top of a layer of a base component made of a highly flexible resin by a commonly used method such as roll coating.

[0044] In another preferred embodiment, the abrasive material of this embodiment may further have loop material (not shown) formed on the back surface of the base portion 3. This embodiment makes it easier to use the abrasive material of this embodiment by attaching it to a sponge pad or the like. Here, "loop material" means a member such as that provided in hook-and-loop fasteners to maintain engagement force. To form the loop material on the back surface of the base portion 3, a commonly used adhesive or tack can be used.

[0045] <Method for manufacturing abrasive material without a substrate>

[0046] Figure 6 is a schematic flowchart illustrating an example of a method for manufacturing the substrate-less abrasive material according to the first embodiment shown in Figure 1. The method for manufacturing a substrate-less abrasive material according to the first embodiment includes a first adhesive layer formation step S1, an abrasive particle dispersion and adhesion step S2, a first composite film formation step S3, and a support peeling step S4.

[0047] (1) Preparation of release sheet (S0) First, a release sheet 10, which is a support with release properties, is prepared (Figure 6(a)). The release sheet 10 can be any support that can be peelably supported on its surface, and is not particularly limited, but examples include silicone-based release treated paper, silicone-based release treated film, fluorine-based release treated paper, fluorine-based release treated film, olefin-based release treated film, and olefin-based release treated paper. It is particularly preferable to use a silicone-based release treated film for the release sheet 10.

[0048] (2) First adhesive layer forming step (S1) After preparing the release sheet, the first adhesive layer formation step (S1) is performed. The first adhesive layer formation step S1 is a step of applying a first adhesive containing at least one of a resin and an elastomer as a base component to the surface of the release sheet 10 to form a first adhesive layer 3a' corresponding to the lower base layer that constitutes the base portion 3 of the substrate-less abrasive material 1 (Figure 6(b)). The first adhesive can be prepared, for example, by blending a base component, a crosslinking agent, a diluent solvent, and a filler as needed in appropriate proportions and stirring and mixing them using a stirrer. The stirrer is not particularly limited, but examples include a disper mixer, an ultra mixer, a homogenizer, and a planetary stirring defoamer.

[0049] (3) Abrasive grain dispersion and adhesion process S2 After the first adhesive layer formation step (S1), the abrasive particle dispersion and adhesion step S2 is performed. The abrasive particle dispersion and adhesion step S2 is a step in which multiple abrasive particles 2 are attached to the first adhesive layer 3a' in a dispersed state (Figure 6(c)). The method for attaching the abrasive particles 3 to the first adhesive layer 3a' can be electrostatic electrodeposition or drop coating. After the abrasive grains are attached, the first adhesive layer 3a' can be solidified (hardened) by drying it in a constant-temperature drying oven, for example, thereby fixing the abrasive grains 2 to the lower base layer of the base.

[0050] (4) First composite film formation step S3 After the abrasive particle dispersion and adhesion process S2, the first composite film formation process S3 is performed. The first composite film formation step S3 is a step in which a first composite film corresponding to a sheet-like substrate-less abrasive is formed on the surface of the support 10 by further applying a second adhesive having the same or different composition as the first adhesive on a first adhesive layer 3a' on which a plurality of abrasive grains 2 are attached in a dispersed state, thereby forming a second adhesive layer 3b' corresponding to the upper base layer that constitutes the base portion 3 of the substrate-less abrasive (Figure 6(d)). The second adhesive can be prepared, for example, by blending a base component, a crosslinking agent, a diluent solvent, and a filler as needed in appropriate proportions and stirring and mixing them using a stirrer. The stirrer is not particularly limited, but examples include a disper mixer, an ultra mixer, a homogenizer, and a planetary stirring defoamer. Furthermore, if the base components constituting the first adhesive layer 3a' and the second adhesive layer 3b' have the same composition, the first composite film is formed as a single film with substantially no interface, as shown in the substrate-less abrasive material 1 in Figure 1. If the first adhesive layer 3a' and the second adhesive layer 3b' have different compositions, it is formed as a two-layer composite film in the form of a sheet, as shown in the substrate-less abrasive material 1A in Figure 2.

[0051] (5) Support peeling process S4 The support peeling step S4 is a step in which the first composite film is peeled off from the release sheet 10, which is the support, to obtain a substrate-less abrasive material 1 (Figure 6(e)).

[0052] The thickness of the release sheet 10 is not particularly limited, but it is preferably in the range of 25 to 100 μm. <Application> The substrate-less abrasive material of this embodiment is used, for example, by cutting it into tape, disc, or other shapes for polishing materials such as metals, ceramics, glass, and single crystals, or surfaces such as magnetic hard disks, magnetic heads, semiconductor substrate surface magnetic heads, lenses, or optical fiber end faces. In particular, the polishing film of this embodiment is suitable for polishing curved exterior painted surfaces, such as the exterior panels of an automobile body.

[0053] Furthermore, since the abrasive material of this embodiment does not have a base material, problems such as the peeling of the abrasive layer from the base material do not occur. In addition, compared to abrasive materials that use a film or sheet made of plastic such as PET as the base material, the amount of waste can be reduced.

[0054] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and includes all aspects included in the concept and claims of the present invention, and can be modified in various ways within the scope of the present invention. [Examples]

[0055] Next, examples and comparative examples will be described to further clarify the effects of the present invention, but the present invention is not limited to these examples.

[0056] (Example 1) Example 1 had the cross-sectional structure shown in Figure 1. The first adhesive was prepared by blending 100 parts by mass of polyester urethane resin, 4 parts by mass of a crosslinking agent (isocyanate-based curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and mixing them uniformly using a stirrer. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains onto the surface of the lower base layer of the base, a second adhesive was prepared by mixing 100 parts by mass of polyester urethane resin, 75 parts by mass of a crosslinking agent (isocyanate-based curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and uniformly stirring it with a stirrer. This second adhesive was then applied using a roll-coating method and dried and cured in a constant-temperature drying oven (120°C) to form the upper base layer (thickness: 7 μm) of the base, and a first composite film corresponding to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains (vertical distance from the bottom surface of the base portion 3 to the tip (vertex) of the abrasive grain 2): 55 μm).

[0057] (Example 2) Example 2 had the cross-sectional structure shown in Figure 2. The first adhesive was prepared by blending 100 parts by mass of polyester urethane resin, 4 parts by mass of a crosslinking agent (isocyanate-based curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and mixing them uniformly using a stirrer. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains to the surface of the lower base layer of the base, a soft epoxy resin mixture (composed of soft epoxy resin, epoxy hardener, and diluent) was applied using a roll-coating method and dried and cured in a constant-temperature dryer (120°C) to form the second adhesive layer, which is the upper base layer (thickness: 7 μm) of the base, and a first composite film equivalent to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. The type A durometer hardness of the soft epoxy resin used in the second adhesive layer was 75. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains: 55 μm).

[0058] (Example 3) Example 3 had the cross-sectional structure shown in Figure 4. The base components were 100 parts by mass of polyester urethane resin, 25 parts by mass of filler (calcium carbonate), 4 parts by mass of crosslinking agent (isocyanate-based curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent. The mixture was then uniformly stirred using a stirrer to prepare the first adhesive. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains to the surface of the lower base layer of the base, a soft epoxy resin mixture (composed of soft epoxy resin, epoxy hardener, and diluent) was applied using a roll-coating method and dried and cured in a constant-temperature dryer (120°C) to form the second adhesive layer, which is the upper base layer (thickness: 7 μm) of the base, and a first composite film equivalent to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. The type A durometer hardness of the soft epoxy resin used in the second adhesive layer was 75. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains: 55 μm).

[0059] (Example 4) Example 4 had the cross-sectional structure shown in Figure 4. The first adhesive was prepared by blending 100 parts by mass of polyester urethane resin, 25 parts by mass of filler (wollonite), 4 parts by mass of crosslinking agent (isocyanate curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and mixing them uniformly using a stirrer. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains to the surface of the lower base layer of the base, a soft epoxy resin mixture (composed of soft epoxy resin, epoxy hardener, and diluent) was applied using a roll-coating method and dried and cured in a constant-temperature dryer (120°C) to form the second adhesive layer, which is the upper base layer (thickness: 7 μm) of the base, and a first composite film equivalent to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. The type A durometer hardness of the soft epoxy resin used in the second adhesive layer was 75. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains: 55 μm).

[0060] (Example 5) Example 5 had the cross-sectional structure shown in Figure 4. The first adhesive was prepared by blending 100 parts by mass of polyester urethane resin, 15 parts by mass of filler (titanium dioxide), 4 parts by mass of crosslinking agent (isocyanate-based curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and mixing them uniformly using a stirrer. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains to the surface of the lower base layer of the base, a soft epoxy resin mixture (composed of soft epoxy resin, epoxy hardener, and diluent) was applied using a roll-coating method and dried and cured in a constant-temperature dryer (120°C) to form the second adhesive layer, which is the upper base layer (thickness: 7 μm) of the base, and a first composite film equivalent to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. The type A durometer hardness of the soft epoxy resin used in the second adhesive layer was 75. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains: 55 μm).

[0061] (Example 6) Example 6 had the cross-sectional structure shown in Figure 4. The base components were 100 parts by mass of polyester urethane resin, 15 parts by mass of filler (potassium titanate), 4 parts by mass of crosslinking agent (isocyanate curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent. The mixture was then uniformly stirred using a stirrer to prepare the first adhesive. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains to the surface of the lower base layer of the base, a soft epoxy resin mixture (composed of soft epoxy resin, epoxy hardener, and diluent) was applied using a roll-coating method and dried and cured in a constant-temperature dryer (120°C) to form the second adhesive layer, which is the upper base layer (thickness: 7 μm) of the base, and a first composite film equivalent to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. The type A durometer hardness of the soft epoxy resin used in the second adhesive layer was 75. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains: 55 μm).

[0062] (Example 7) Example 7 had the cross-sectional structure shown in Figure 4. The first adhesive was prepared by blending 100 parts by mass of polyester urethane resin, 15 parts by mass of filler (potassium titanate), 4 parts by mass of crosslinking agent (isocyanate curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and stirring uniformly using a stirrer. Next, a first adhesive layer was formed by uniformly applying the first adhesive to a silicone-released carrier film (release sheet) using the comma method, so that the film thickness after drying would be 25 μm. Subsequently, alumina abrasive grains with a particle size of P400 (ds-50 particle size: 35 μm) were attached to the first adhesive layer by electrostatic electrodeposition, and dried using a constant-temperature drying oven (temperature: 120°C) to form the lower base layer (thickness: 25 μm) of the base portion. The carrier film used was Nan Ya Plastics Corp. model number: H375A, with a thickness of 75 μm. Next, to more firmly fix the abrasive grains onto the surface of the lower base layer of the base, a second adhesive was prepared by mixing 100 parts by mass of polyester urethane resin, 75 parts by mass of a crosslinking agent (isocyanate-based curing agent), and an appropriate amount of methyl ethyl ketone (MEK) as a diluent, and uniformly stirring it with a stirrer. This second adhesive was then applied using a roll-coating method and dried and cured in a constant-temperature drying oven (120°C) to form the upper base layer (thickness: 7 μm) of the base, and a first composite film corresponding to a sheet-like substrate-less abrasive was formed on the surface of the release sheet. Then, the first composite film was peeled off from the release sheet to obtain the substrate-less abrasive material of Example 1 (total thickness including abrasive grains: 55 μm).

[0063] (Conventional example 1) Conventional Example 1 is an abrasive material having a base material and a cross-sectional structure as shown in Figure 7. The base material is PET (Toyobo A-4360) with a thickness of 75 μm, and the abrasive layer formed on the base material consists of alumina abrasive grains with a grit size of P400 (ds-50 particle size: 35 μm). The first adhesive is a urethane resin, and the thickness of the first adhesive layer is 6 μm. The second adhesive is a phenolic resin that is harder than a hard epoxy resin (Type A durometer hardness: 96), and the thickness of the second adhesive layer is 30 μm.

[0064] (Conventional example 2) Conventional Example 2 has the configuration shown in Figure 7 and is an abrasive material having a base material, the base material being thermoplastic polyurethane (TPU) with a thickness of 35 μm, and the abrasive layer formed on the base material being alumina abrasive grains with a grit size of P400 (ds-50 particle size: 35 μm), the first adhesive being urethane resin, and the thickness of the first adhesive layer being 14 μm. The second adhesive being urethane resin, and the thickness of the second adhesive layer being 25 μm.

[0065] (Comparative Example 1) Comparative Example 1 was manufactured using the same method as in Example 1, except that a hard epoxy resin (Type A durometer hardness: 96) was used instead of a polyester-based urethane resin as the base component of the first adhesive and the second adhesive layer.

[0066] <Evaluation of the mechanical properties of abrasive materials> (I) Durometer hardness The durometer hardness of a substrate-less abrasive can be measured by stacking test pieces, for example, 20 mm x 20 mm in size, to a thickness of 2.5 mm or more, and slowly pressing a durometer (model number: GS-706N (manufactured by Teclock Co., Ltd.)) so that the indenter is perpendicular to the measurement surface.

[0067] (II) Tensile strength The method for measuring the tensile strength of a substrate-less abrasive involves cutting the prepared substrate-less abrasive into a 25mm x 150mm test piece, and using a Tensilon universal testing machine RTG-1225 (manufactured by A&D Company, Limited), pulling the test piece in the longitudinal direction under conditions of a chuck distance of 100mm and a tensile speed of 200mm / min. The maximum point load at that time can be measured as the tensile strength (MPa).

[0068] (III) Tensile elongation The method for measuring the tensile elongation of a substrate-less abrasive involves cutting the prepared substrate-less abrasive into a 25mm x 150mm test piece, and using a Tensilon universal testing machine RTG-1225 (manufactured by A&D Co., Ltd.), the test piece is pulled in the longitudinal direction under conditions of a chuck distance of 100mm and a tensile speed of 200mm / min. The maximum elongation at that time can be measured as the tensile elongation (%).

[0069] <Performance evaluation of abrasive materials> The abrasives were evaluated for their abrasive properties and conformability. (i) Abrasiveness A loop material with an adhesive layer was laminated to the carrier film release surface of the abrasive to obtain a φ125mm abrasive disc. A stainless steel (SUS) flat plate (size: 200mm x 400mm) spray-painted with nax Multi Eco [3:1] 20LX Clear (manufactured by Nippon Paint) was prepared as the workpiece to be polished. As a preliminary step to the test, it was polished back and forth 5 times by hand using CLOG FREE #320 (manufactured by Sankyo Rikagaku Co., Ltd.). As a test step, the abrasive was attached to a Double Action Sander 914L (manufactured by Compact Tool Co., Ltd.) and a cushion pad Super Asile Pad (manufactured by KOVAX Co., Ltd.), and polished back and forth 10 times at an air pressure of 0.45 Pa. The removal of polishing marks from the previous step was checked every 5 back and forth. The polishing performance was evaluated in three stages based on the following evaluation criteria. The evaluation results are shown in Table 1. In this example, a polishing performance evaluation of "1" and "2" was considered to be good and an acceptable level, while "3" was considered to be an unacceptable level of polishing performance.

[0070] [Evaluation Criteria] If polishing marks can be removed in 1:5 back-and-forth strokes If polishing marks could not be removed with 2:5 back-and-forth strokes, but were removed with 10 back-and-forth strokes: If polishing marks cannot be removed even after 3:10 round trips

[0071] (ii) Followability To evaluate the conformability of the test, a car hood panel (size: 1350mm x 700mm) with a gentle R-shaped surface, spray-painted with nax Multi Eco [3:1] 20LX Clear (manufactured by Nippon Paint), was prepared as the workpiece. Using a double-action sander 914L (manufactured by Compact Tool Co., Ltd.) and abrasive material attached to a cushion pad Super Asile Pad (manufactured by KOVAX Co., Ltd.), the sander was moved back and forth in a linear trajectory perpendicular to the R-shaped surface at a constant speed (0.3m / s) for a constant time (2 seconds (1 reciprocation)) at an air pressure of 0.45 Pa. If there was a difference in the finish after polishing between the center and the outer edge of the workpiece (exterior panel), this was defined as polishing unevenness. The degree of polishing unevenness within the polished area (area size: 125mm x 300mm) was measured, and the conformability of the test when polishing uneven curved surfaces was evaluated on a three-point scale as follows. The evaluation results are shown in Table 1. In this embodiment, a polishing performance rating of "1" or "2" was considered acceptable, while a rating of "3" was considered unacceptable.

[0072] [Evaluation Criteria] 1: Whether or not there are any uneven polishing marks, If the polished area is less than 5%. 2: If polishing unevenness occurs in 5% to less than 20% of the polished area. 3. If polishing inconsistencies occur in 20% or more of the polished area.

[0073] [Table 1]

[0074] As shown in Table 1, all of the substrate-less abrasives in Examples 1 to 7 exhibited good conformability to uneven curved surfaces (the ability to deform to conform to the surface being polished) and had excellent polishing properties. On the other hand, both Conventional Example 1 and Comparative Example 1 exhibited poor conformability to uneven curved surfaces of the surface to be polished. Furthermore, since both Conventional Example 1 and Conventional Example 2 are abrasives with a base material, the amount of waste increased, and during polishing, the polishing layer containing the grinding wheel sometimes peeled off from the base material at the adhesive interface, resulting in insufficient polishing performance. [Explanation of symbols]

[0075] 1. Abrasive material without substrate 2, 2B abrasive grains 3, 3A, 3B Base section 3a Lower base layer constituting the base portion 3A 3b Upper base layer constituting the base portion 3A Lower base layer constituting base section 3C Upper base layer constituting the 3D base section 3C 3a' First adhesive layer 3b' Second adhesive layer 4 Filler 5. Resin or elastomer 10 Release sheets 100 Abrasive 102 abrasive grains 103 Adhesive 104 Base material 105 Polishing layer

Claims

1. A base portion containing a total of 60% by volume or more of at least one of the base components of resin and elastomer, The base portion contains a plurality of abrasive grains held in a dispersed state and It consists only of a sheet-like composite film having the following properties: The composite film is The Type A durometer hardness measured according to the hardness test specified in JIS K7311-1995 is 50 to 80. The tensile strength is 70 to 250 MPa, and, Abrasive material with a tensile elongation of 10 to 360%.

2. The abrasive material according to claim 1, wherein the base component of the base portion is urethane resin.

3. The base portion is composed of two layers: a lower base layer and an upper base layer. The base component of the lower base layer is urethane resin, and The abrasive material according to claim 1, wherein the base component of the upper base layer is a soft epoxy resin.

4. The abrasive material according to claim 3, wherein the ratio of the thickness of the lower base layer to the thickness of the upper base layer is in the range of 30:1 to 2:

1.

5. The abrasive material according to claim 1, wherein the base portion further contains a filler having the property of increasing the tensile strength and decreasing the tensile elongation of the abrasive material.

6. A method for producing an abrasive material according to any one of claims 1 to 5, A step of forming a first adhesive layer by applying a first adhesive containing at least one base component of resin and elastomer to the surface of a releaseable support, The first adhesive layer is formed by a step of attaching a plurality of abrasive particles in a dispersed state, The process involves forming a sheet-like composite film equivalent to an abrasive on the surface of the support by further applying a second adhesive having the same or different composition as the first adhesive to the first adhesive layer on which the plurality of abrasive particles are attached in a dispersed state, thereby forming a second adhesive layer. The process of peeling the composite film from the support to obtain the abrasive, A method for manufacturing abrasives, including the method described above.

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