Surface conditioning article

Abstract

A surface conditioning article is presented, which includes a hub portion containing a first material. The first material does not contain abrasive particles. Further, the article includes a plurality of elongated abrasive elements, each extending along an element axis, and each of the primary elongated abrasive elements contains a second material.

Description

Background Art

[0001] Surface conditioning disks and brushes are commonly known for various cleaning, finishing, and deburring applications. Some surface conditioning articles contain abrasive particles.

Summary of the Invention

[0002] Brushes have been used to polish, clean, and grind various substrates. These brush products typically have a plurality of brush bristles that contact the substrate. Abrasive particles can be added to the brush bristles to improve their abrasiveness. However, abrasive particles are not required for all surface conditioning applications.

[0003] The systems and methods described herein form a brush product in a two-step operation to improve and control the characteristics of a hub portion that is different from the bristle portion of a radial brush bristle brush.

[0004] A surface conditioning article is presented, which includes a hub portion containing a first material. The first material does not contain abrasive particles. Further, the article includes a plurality of elongated abrasive elements, each extending along an element axis, and each of the primary elongated abrasive elements contains a second material.

[0005] A method of forming an abrasive article is presented, which includes causing a first material to fill a first mold, and the step of forming a hub with the first material within the first mold. Further, the method includes causing a second material to fill a second mold. The second material forms a plurality of elongated abrasive elements extending from the hub. Further, the mixture is solidified so that the elongated abrasive elements are bonded to the hub, and the step of bonding the second material to the first material is included. The first material does not contain abrasive particles, and the second material contains abrasive particles.

[0006] The above summary is not intended to explain each embodiment or all examples of the invention described in this specification. Rather, it is intended that the invention be understood and evaluated by referring to the following description and claims based on the accompanying drawings and figures.

[0007] These and other aspects of the invention will become apparent from the following detailed description. However, the above summary should not be construed as limiting the scope of the claimed subject matter, which is defined only by the appended claims that may be amended during the pendency of the application.

Brief Description of the Drawings

[0008]

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[0009] The terms "preferred" and "preferably" refer to the embodiments described herein that may provide certain benefits under certain circumstances. However, other embodiments may be preferred under the same or different circumstances. Further, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

[0010] As used in this specification and the appended claims, the singular forms "a", "an", and "the" are to be construed as including plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a" or "the" component may include one or more components and their equivalents known to those skilled in the art. Further, the term "and / or" means any one or all of the listed elements or any combination of any two or more of the listed elements.

[0011] It should also be noted that "comprises" and variations thereof do not have a limiting meaning in the descriptions provided herein. Further, "a", "an", "the", "at least one", and "one or more" are used interchangeably herein.

[0012] Relative terms such as left, right, front, rear, top, bottom, side, upper side, lower side, horizontal, and vertical, as used herein, are from the perspective in a particular drawing. These terms are used only to simplify the description and do not limit the scope of the present invention in any way.

[0013] References throughout this specification to "one embodiment", "certain embodiments", "one or more embodiments", or "an embodiment" mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one or more embodiments", "in certain embodiments", "in one embodiment", or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0014] The "surface conditioning articles" described herein may include articles used for cleaning, debris removal, surface polishing (e.g., grinding, texturing, refining, deburring, sanding), or other suitable operations. Some of the surface conditioning articles described herein may include abrasive particles in one or more components. However, in the embodiments of this specification, it is explicitly contemplated that many surface conditioning articles are formed without including abrasive particles.

[0015] The surface conditioning article 10 and assembly according to the present disclosure can, as described herein, take the form of a brush hair brush (rotary or otherwise), a disk, or a component of a brush or disk.

[0016] Referring to FIGS. 1 and 2, the surface conditioning article 10 may include a hub 104. A plurality of primary elongate elements 100 (e.g., brush hairs 14) may project outwardly from the hub 104 from the root 22 of the element (i.e., the end closest to the hub 104) to the end 106 of the element (i.e., the end farthest from the hub 104). There may be a space between the roots 22 of the elements, and the outer edge 23 of the hub 104 may be exposed. Alternatively, adjacent elements 100 may be in contact with each other at the roots 22. However, in FIGS. 1 and 2, although the brush hairs 14 are shown extending from the hub 104 and the brush hairs 14 and the hub 104 are in the same plane, it is explicitly contemplated that the brush hairs 14 may extend from the hub 104 at any suitable angle. For example, in certain embodiments, the brush hairs 14 may extend perpendicular to the hub 104. Also, in other embodiments, the brush hairs 14 may extend from the hub 104 at any angle within the range of 0 degrees to 90 degrees.

[0017] The article 10 may be integrally molded such that the primary elongate element 100 and the hub 104 are continuous with each other. The connection point between the brush hair 14 and the hub 104, e.g., the root 22 of the element, is vulnerable to breakage, which may cause premature wear and a shortened service life of the surface conditioning article 10.

[0018] In certain embodiments, the article 10 is an abrasive article and may include a composition of abrasive particles. The abrasive particles may be integrated into, coated on, or embedded in the surface of the brush hairs 14 such that when the abrasive article 10 contacts the surface, the surface can be abraded. FIG. 1 shows an abrasive article rotating in the direction indicating the direction of rotation, but other forms of abrasive articles that benefit from the embodiments described herein, such as a vibrating brush, are also explicitly contemplated.

[0019] Incorporating abrasive particles into the brush bristles 14 or coating the brush bristles 14 presents manufacturing challenges because it increases the wear rate of the manufacturing parts during the manufacturing process of the abrasive article 16. For example, the abrasive particles may cause wear on containers that hold or transport the molten abrasive particle - resin mixture, or on parts that extrude the abrasive particle - resin mixture onto a substrate or pour it into a mold. It is desired to reduce wear and damage during manufacturing by reducing the amount of material containing the abrasive particles required for forming the article 10.

[0020] The abrasive article according to the present disclosure may optionally include an elongated abrasive element that includes a combination of formed abrasive particles and other abrasive or non - abrasive particles (e.g., crushed abrasive particles, filler particles, abrasive aids, etc.).

[0021] A plurality of articles 10 may be assembled on a spindle to form an abrasive assembly. Such an example is as shown and described in relation to FIGS. 3A and 3B of U.S. Patent No. 5,903,951 by Ionta et al. Any number of articles 10 may be assembled together to provide an abrasive assembly of a desired width. Preferably, the articles 10 are adjacent to each other with substantially no gap between the articles. On the other hand, the articles 10 may be assembled axially with a space provided between adjacent articles. For example, 5 to 10,000 articles 10 may be assembled to form an abrasive assembly, although more or fewer may be used as needed. Engagement means may be provided between the segments to reduce or eliminate the rotation of adjacent articles relative to each other. Such engagement means may include, for example, a mating serrated pattern on the surface of the hub 104 or a pattern of holes and dimples.

[0022] The materials, manufacturing processes, and configurations of the articles are determined according to the desired finishing applications. As used herein, the term "refine" includes at least one of removing a portion of the workpiece surface, applying a surface finish to the workpiece, removing surface scale, removing surface burrs, cleaning the workpiece surface (including removing paint and other coatings, gasket materials, corrosion, oil residues, or other foreign matter or debris), or combinations thereof. In some applications, it may be desirable to provide aggressive polishing characteristics, in which case the article may include polishing particles, larger-sized polishing particles, harder polishing particles, sharper polishing particles, more easily crushed polishing particles, particles of a shape suitable for a particular operation, a higher polishing particle-to-binder ratio, or combinations thereof. In other applications, it may be desirable to provide a surface finish such as precision finishing or to clean the surface without removing the surface material itself, in which case the article may use smaller polishing particles, softer polishing particles, a lower polishing particle-to-binder ratio, or combinations thereof. To obtain the desired polishing characteristics, it is possible to use formed polishing particles 200 of various compositions and hardnesses or a mixture of formed polishing particles and conventional polishing particles.

[0023] However, it is also possible to achieve the desired surface conditioning using a surface conditioning article that does not include polishing particles. For example, a harder resin may be sufficient to form brush bristles to remove surface features or clean the surface. For example, using a hard resin, gaskets can be removed from a metal surface.

[0024] In some embodiments of this specification, the polishing article 10 may have a hub 104 from which a number of brush bristles 14 may extend. As shown in FIG. 1, in one embodiment, the hub 104 is generally a planar continuous circumferential portion. However, the hub may have a contoured shape or a curved surface. For example, the hub 104 may be convex, concave, or conical. When the hub 104 is conical, the primary elongated polishing element 100 may extend parallel to the conical surface defined by the hub.

[0025] The article 10 may optionally have an attachment mechanism such as a channel, a keyway, or a base for mechanically coupling a plurality of articles to a drive mechanism (e.g., a shaft) as part of the hub 104. The hub 104 may include one or more attachment holes into which a lock rod and / or a shaft can be inserted. Thereafter, the shaft and / or the lock rod may be attached to a suitable rotational drive mechanism.

[0026] The thickness of the hub 104 is preferably about 0.5 - 25 mm, more preferably about 1.0 - 10 mm, still more preferably about 1.5 - 6 mm, and most preferably about 1.5 - 3 mm. As shown in FIGS. 1 and 2, the hub 104 may be circular. The diameter of the outer edge 23 of the hub 104 is preferably about 2.5 - 61.0 cm (1.0 - 24.0 inches), although smaller or larger hubs are also included within the scope of the present invention. In one preferred embodiment, the hub 104 is composed of a suitable flexible material and thickness to help more brush bristles contact an uneven or irregular workpiece. The hub 104 can preferably be bent by at least 10°, more preferably at least 20°, still more preferably at least 45° without damage or substantial permanent deformation. Hub shapes other than circular are also included within the scope of the present invention. This includes, but is not limited to, elliptical, rectangular, square, triangular, rhombic, and other polygonal shapes. Also included are relatively hard or non-flexible hubs.

[0027] The hub 104 may instead be a ring sector bounded on each side by a radial edge. Such a ring sector is described in U.S. Patent No. 5,903,951 by Ionta et al. Preferably, the ring sector has an angular width such that an integer number of ring sectors can be assembled as a circumferential article. For example, four 90° ring sectors can be arranged to create a 360° circumferential article.

[0028] In some embodiments, the hub 104 is integrally molded with the primary elongated abrasive element 100 to provide a single unitary article. As such, no adhesive or mechanical attachment means are required to attach the primary elongated abrasive element 100 to the hub 22. In such embodiments, the hub 104 and the primary elongated abrasive element 100 may be molded simultaneously.

[0029] A surface conditioning article according to the embodiments described herein may be formed in a two-step process. First, the hub 104 is formed, and then the brush filaments 14 containing abrasive particles are formed. However, molding the brush filaments first and then the hub is also explicitly contemplated. In some embodiments, the hub 22 and the brush filaments 14 may be formed using a co-injection molding process. In this case, the second material is injected into the mold while the first material is still in a fluid state. For example, after injecting the material for the brush filaments, the material for the hub can be injected and the material for the brush filaments can be pushed into the void portions of the mold.

[0030] Figures 4A and 4B illustrate the first step of the abrasive article forming process. A mixture 400 is supplied to a mold 410 through a gate 420. The material 400 does not contain abrasive particles. The material 400 may be a single polymer or other resin, or a mixture of polymer and resin materials. The material 400 may be a curable mixture, a molten mixture, or a suitable compound that can be injected, extruded, injected, or otherwise supplied to the mold 410 through the gate 420.

[0031] As a result, a first component 450 may be formed, which includes a hub portion 460, and in certain embodiments, at least a portion of the material 400 may be used to form a portion of the elongated abrasive element 100. As shown in FIG. 4B, a brush hair connection point 470 extends outwardly from the hub 460.

[0032] The first component 450 is, in the embodiments described herein, an integral structure and has a consistent composition throughout the structure.

[0033] The first component 450 may be used in a second mold, as shown in FIG. 5A. In this case, an integrally formed hub 540 is disposed within the mold 530, and a material 510 containing abrasive particles 512 flows through a gate 520 to coat the first component 540. However, although two separate molds are shown with respect to FIGS. 4A - 4B, it is expressly contemplated that co - injection molded parts or a single mold that accepts multiple injections simultaneously or sequentially are also possible.

[0034] Furthermore, FIGS. 5A and 5B show the system 500 completely coating the entire first component 540 with the second material 510, but it is also expressly contemplated that the second material 510 may coat only a portion of the first component 540, such as the brush hair connection portion 570.

[0035] As shown in FIG. 5B, the brush hair connection portion 570 may extend into an elongated portion 560 of the second mold 550. By having the first material extend into the brush hair forming portion 560 of the mold 550, the performance characteristics can be adjusted for a particular application. For example, the first material 400 may have a stiffness coefficient and may result in a reduction in the flexibility of the resulting brush hairs. Alternatively, the first material 400 may impart other attributes. Also, the bond between the first material 400 and the second material 510 can be improved, potentially reducing premature breakage of the brush hairs during use.

[0036] The material 500 may be a single polymer or other resin, or a mixture of polymer and resin materials. The material 500 may be a curable mixture, a molten mixture, or a suitable compound that can be injected, extruded, injected, or supplied to the mold 510 through the gate 520 by other methods.

[0037] As described herein, in certain embodiments, the difference between the first material 400 and the second material 510 may only be that the second material 510 contains abrasive particles 512. However, it is also contemplated that the first material 400 may have a completely different composition from the second material 510. However, by limiting the abrasive particles 512 to the second step (material 510), the amount of abrasive particles 512 passing through the system 500 is reduced, reducing the overall wear and tear of the system 500.

[0038] Furthermore, within the scope of the present invention, it is also possible to include abrasive particles in both insertion steps. The first insertion may include abrasive particles having a specific size, material, and / or hardness, and the second insertion may include different abrasive particles. During polishing, the abrasive particles near the end or distal end are used first, and then the abrasive particles near the proximal end (i.e., near the end connected to the hub 22) are used.

[0039] The primary elongated polishing element 100 extends from the outer edge 23 of the hub 22, starting at the root 104 of the element and ending at the end 106 of the element located away from the hub 22. In one preferred embodiment, the primary elongated polishing element 100 extends radially from the outer edge 23 of the hub 22 and is in the same plane as the hub 22. To facilitate shaping (detailed below), it may be preferable to arrange the primary elongated polishing elements 100 in a single row around the outer edge 23 of the hub 22. Also, two rows of brush bristles may be formed. The primary elongated polishing element 100 may extend from the outer edge 23 in a plane parallel to the plane of the hub 22, regardless of whether the hub 22 is planar, conical, or other shape. Alternatively, the primary elongated polishing element 100 may extend from the outer edge 23 at any oblique angle with respect to the applied plane of the hub 22.

[0040] The first elongated abrasive element 100 may optionally have a cross-sectional area A. This cross-sectional area includes, but is not limited to, circular, star-shaped, semi-circular, four semi-circular, elliptical, rectangular, square, triangular, diamond-shaped, or other polygonal shapes. In one embodiment, the first elongated abrasive element 100 has a constant cross-section along its length. In other embodiments, the first elongated abrasive element 100 may have a non-constant or variable cross-section along its length.

[0041] The first elongated abrasive element 100 may be formed in a tapered shape such that the cross-sectional area A decreases from the base 104 of the element towards the end 106 of the element. The tapered first elongated abrasive element 100 may have any of the cross-sectional shapes described above. The first elongated abrasive element 100 may be subject to bending stress when the article 10 rotates relative to the workpiece. This bending stress may be highest at the base 104 (position of the outer edge 23) of the first elongated abrasive element 100. Therefore, in certain embodiments, a tapered element may be more resistant to bending stress than an element having a constant cross-sectional area A. The first elongated abrasive element 100 may have a taper over its entire length, or may have a taper in a portion adjacent to the base 104 of the element and a constant cross-sectional area A in other portions. The taper may include any suitable angle. Also, the article 10 may include a fillet radius at the connection portion between the base 104 of the element and the outer edge 23 of the hub 22.

[0042] The first elongated abrasive element 100 has an aspect ratio defined as the value of the length from the root 104 of the outer element to the end 106 of the element divided by the width of the element. In the case of a tapered element, the width is defined as the average width along the length. In the case of a non-circular cross-section, the width is measured as the longest width in the plane (e.g., the diagonal in the case of a square cross-section). The aspect ratio of the first elongated abrasive element 100 is preferably at least 2, more preferably about 5 to 100, and even more preferably about 50 to 75. The size of the first elongated abrasive element 100 is selected according to the specific use of the article 10 and the brush. The length of the first elongated abrasive element 100 is preferably about 0.2 to 50 cm, more preferably about 1 to 25 cm, and even more preferably about 5 to 15 cm. The width of the first elongated abrasive element 100 is preferably about 0.25 to 10 mm, more preferably about 0.5 to 5.0 mm, even more preferably about 0.75 to 3.0 mm, and most preferably about 1.0 to 2.0 mm. The width of the first elongated abrasive element 100 may be the same as or different from the thickness of the hub 22. In one preferred embodiment, all the first elongated abrasive elements 100 have the same dimensions. On the other hand, the first elongated abrasive elements 100 on a brush including a plurality of articles 10 may have different dimensions, such as different lengths, widths, or cross-sectional areas. For example, the article 10 may have two groups of short first elongated abrasive elements and two groups of long first elongated abrasive elements, which is similar to that shown in FIG. 9 of U.S. Patent No. 5,903,951 by Ionta et al. It is also possible to arrange ring sector segments having elements of different lengths. Regarding the brush polishing assembly, adjacent articles 10 may have different elements. Similarly, in some embodiments, two different groups of brush bristles may differ in hardness (e.g., resin durometer). For example, a set of "soft" brush bristles may be alternately arranged with a set of "hard" brush bristles. By alternately arranging soft and hard brush bristles, high-speed finishing and cleaning are possible, and in some cases, the quality of the surface finish may also be improved.

[0043] The density and arrangement of the primary elongate abrasive elements 100 are selected according to the particular use of the article 10 and the brush. The primary elongate abrasive elements 100 may be evenly arranged around the outer edge 23 of the hub 22. Alternatively, the primary elongate abrasive elements 100 may be arranged in groups, with gaps between the groups. Also, in the plane of the hub 22, they may be arranged at an angle other than radially outward (i.e., an angle other than zero with respect to the radius of the hub 22). Thus, the article 10 may have a portion that does not include the primary elongate abrasive elements 100 on a part of the outer edge 23 of the hub 22. The elements may be present only on a part of the outer edge 23 of the hub 22 or substantially throughout. The primary elongate abrasive elements 100 may or may not be in contact with adjacent elements.

[0044] The material, length, and configuration of the primary elongate abrasive elements 100 are preferably selected to have sufficient flexibility to assist in finishing an uneven or irregular workpiece. The primary elongate abrasive elements 100 can be bent up to at least 25°, more preferably at least 45°, even more preferably at least 90°, and most preferably about 180° without causing damage or substantial permanent deformation to the elements.

[0045] In addition to the reinforcement that the first material 400 may provide, it is also possible to reinforce the primary elongate abrasive elements 100 with any suitable structure. For example, it is possible to place reinforcing fibers or wires in the mold cavity of the element and inject the material 400 around the reinforcing wires. Thereby, an element 100 with the reinforcing wires or fibers embedded therein is obtained.

[0046] In one embodiment, the primary elongated abrasive element 100 is inclined rearwardly at an angle with respect to the radius of the hub in a direction opposite to the rotational direction of the article. Such an arrangement can minimize breakage of the primary elongated abrasive element 100 near the root where the brush bristles are attached to the outer edge 23 of the hub 22. When the article rotates and the ends of the brush bristles contact the workpiece, the brush bristles tend to bend in a direction opposite to the rotational direction (see FIG. 9). If this bending force becomes excessive, the element 100 may break at its root. When the article described in this embodiment rotates about an axis that is perpendicular to the hub 22 and passes through the center of the attachment means, the rearwardly inclined primary elongated abrasive element 100 is subject to centrifugal force. This force causes the element 100 to bend toward a radial line. The bending due to this centrifugal force acts in a direction opposite to the bending caused by the contact of the brush bristles with the workpiece. Therefore, the brush bristles can withstand greater bending caused by the workpiece than the brush bristles initially arranged along the radius. The angle at which the element is inclined rearwardly is preferably up to 45°, more preferably about 5° - 35°, still more preferably about 10° - 30°, and most preferably about 22.5°. However, other angles can be used if necessary. In one embodiment, the hub 22 of the article 10 has an outer diameter of about 2.5 cm (1 inch) and a thickness of about 2.5 mm (0.1 inch) at the outer edge 23, and includes 30 primary elongated abrasive elements 100 extending outwardly from the outer edge 23 within the plane of the hub 22. Each element 100 has a length of about 2.25 cm (0.88 inch) and tapers from a thickness of about 3.0 mm (0.12 inch) at the root to a thickness of about 2.0 mm (0.08 inch) at the end, and generally has a square cross-section. The dimensions of the article 10 and the number of primary elongated abrasive elements 100 described as such are merely examples of one preferred embodiment and the present invention is not limited thereto.

[0047] In some embodiments, the primary elongated abrasive element 100 has an angle β with respect to the plane of the hub 22 (shown and described in FIGS. 21 and 22 of U.S. Patent No. 5,903,951 by Ionta et al.). The disclosure of this patent is incorporated herein by reference in its entirety.

[0048] As used herein, the term "abrasive particles" may mean any suitable abrasive particles, including crushed abrasive particles, rod-shaped abrasive particles, shaped abrasive particles, partially shaped abrasive particles, precisely shaped abrasive particles, fragments of abrasive particles, and other suitable abrasive elements.

[0049] As used herein, the term "shaped abrasive particles" means abrasive particles intentionally formed so that at least a portion thereof has a predetermined shape. This shape is often replicated from a mold cavity or other shaping tool used to form the precursor shaped abrasive particles. Shaped abrasive particles generally have a predetermined geometric shape that substantially reproduces the shape of the mold cavity or shaping tool used. The cavity or tool may be present on the surface of an embossing roll or may be included within a flexible belt or production tool. Also, shaped abrasive particles can be extruded and cut to a predetermined length or precisely cut from a sheet of dried sol-gel (or other precursor or cured material if not ceramic-based) by a laser beam to obtain the desired geometric shape. Additionally, shaped abrasive particles may be manufactured by injection molding or 3D printing.

[0050] Shaped abrasive particles have a maximum dimension "M", a thickness "T" orthogonal to the maximum dimension M, a particle axis defined along the maximum dimension M, and a particle plane that includes the particle axis and is orthogonal to the thickness T. As described in U.S. Patent Publication No. 2022 / 0016745, published on January 20, 2022, in certain embodiments, the abrasive particles are precisely directionally aligned along the brush bristles, and the particle plane of a first abrasive particle may be parallel to the particle plane of a second abrasive particle. In some embodiments, the shaped abrasive particles may be more precisely directionally aligned along the element axis than when they are random. In some embodiments, at least 50% of the shaped abrasive particles may be precisely directionally aligned along the element axis. Also, in some embodiments, at least 66% of the shaped abrasive particles may be precisely directionally aligned along the element axis.

[0051] As described above, in addition to, or alternatively to, a certain amount of the formed abrasive particles being accurately directionally aligned, in some embodiments, the formed abrasive particles may generally be directionally aligned along the element axis (as described in U.S. Patent Publication No. 2022 / 0016745, published on January 20, 2022). "Generally directionally aligned" means that the particle plane is oriented within 60° from parallel to the element axis. In some embodiments, at least 50% of the formed abrasive particles may generally be directionally aligned along the element axis. Further, in some embodiments, at least 66%, at least 75%, at least 90%, at least 95%, or at least 96% of the formed abrasive particles may generally be directionally aligned along the element axis.

[0052] As can be understood from the above, the formed abrasive particles that are accurately directionally aligned are also generally directionally aligned, but the formed abrasive particles that are generally directionally aligned are not necessarily accurately directionally aligned. In one embodiment, at least a majority of the formed abrasive particles are accurately directionally aligned, and at least 75% of the formed abrasive particles may generally be directionally aligned. Also, in other embodiments, at least a majority of the formed abrasive particles are accurately directionally aligned, and at least 90% or 95% of the formed abrasive particles may generally be directionally aligned. Further, in one embodiment, at least 66% of the formed abrasive particles are accurately directionally aligned, and at least 95% of the formed abrasive particles may generally be directionally aligned.

[0053] In addition to, or in combination with, the above-described embodiments in which the formed abrasive particles are generally or accurately directionally aligned, in some embodiments, the particle axes of at least 40% of the formed abrasive particles may be within 5° from parallel to the element axis 101, or the particle axes of at least 60% of the formed abrasive particles may be within 10° from parallel to the element axis.

[0054] It should be understood that these combinations are merely examples and that any suitable combination within the scope applicable within the present disclosure can be selected.

[0055] The orientation of the abrasive particles formed within the elongated abrasive element can be achieved by any method capable of achieving the orientation to the extent and frequency described herein. For example, methods described in U.S. Patent Publication No. 2022 / 0016745, published on January 20, 2022, are exemplified, but are not limited thereto.

[0056] The hub 22 may further have reinforcing properties such as a fiber-reinforced substrate. The reinforcing means can include, for example, cloth, non-woven sheet, mat, mesh, screen, etc., and may also include individual fibers mixed into a moldable polymer and dispersed throughout the article. The reinforcing means may optionally be subjected to a process that changes its physical properties. The purpose of the reinforcing means is to improve the bending strength and tensile strength of the article 10 and suppress the progression of cracks. Examples of reinforcing fibers suitable for the present invention include glass fibers, metal fibers, carbon fibers, wire mesh, mineral fibers, fibers formed from heat-resistant organic materials, thermoplastic or thermosetting fibers, fibers made from ceramic materials, etc. The reinforcing fibers may have an adhesion promoter or compatibilizer on the fiber surface. Examples of other organic fibers include polyvinyl alcohol fibers, nylon fibers, polyester fibers, and phenol fibers. In some embodiments, the moldable polymer mixture preferably includes a coupling agent such as a silane coupling agent, a phosphate coupling agent, a zirconate coupling agent, or a titanate adhesion promoter, thereby improving adhesion to the thermoplastic material.

[0057] The materials 400 and 510 may be any suitable materials that can be molded, extruded, or otherwise formed as in the embodiments described herein. The material 400 may be the same as or different from the material 510.

[0058] Materials 400 and / or 510 may contain a formable polymer material, which are organic binder materials that are formable, i.e., deformable under heating to form a desired shape. The formable polymer may be a thermoplastic polymer, a thermosetting polymer, a thermoplastic elastomer, or a combination thereof. In the case of a thermoplastic polymer, when the organic binder is heated to a temperature above its melting point, the polymer flows. As a result, the thermoplastic polymer flows into the mold cavity to form the article 10. Thereafter, the article is cooled and the thermoplastic binder solidifies. In the case of reaction injection molding, the thermosetting polymer is in a thermoplastic state during molding and flows into the mold cavity when heated to a temperature above its melting point. Thereafter, the organic binder crosslinks at room temperature or high temperature. Examples of suitable thermosetting polymers include styrene-butadiene rubber, polyurethane, urea-formaldehyde, epoxy, and phenolic resin.

[0059] Materials 400 and / or 510 may contain a thermoplastic polymer. Examples of suitable thermoplastic polymers include polycarbonate, polyetherimide, polyester, polyethylene, polysulfone, polystyrene, polybutylene, acrylonitrile-butadiene-styrene block copolymer, polypropylene, acetal polymer, polyurethane, polyamide, and combinations thereof. Generally, the thermoplastic polymers preferred in the present invention are those having a high melting point and good heat resistance characteristics. Thermoplastic polymers may be preferably used in low-speed applications of the article 10 where the stress during operation is relatively low. An example of a commercially available thermoplastic polymer suitable for the present invention is GRILON CR9, which is a copolymer of NYLON 6,12 available from EMS-American Grilon, Inc. (Sumter, South Carolina).

[0060] As a specific thermoplastic polymer suitable for the embodiments of this specification, a polyamide resin material having an amide group (--C(O)NH--) can be mentioned. Various types of polyamide resin materials, namely nylon, can be used. For example, nylon 6 / 6 and nylon 6 are included. Nylon 6 / 6 is a condensation product of adipic acid and hexamethylenediamine. Nylon 6 / 6 has a melting point of about 264 °C and a tensile strength of about 770 kg / cm 2 ². Nylon 6 is a polymer of ε-caprolactam. Nylon 6 has a melting point of about 220 °C and a tensile strength of about 700 kg / cm 2 ². Examples of commercially available nylon resins that can be used as a backing material for the articles of the present invention include "VYDYNE" from Ascend Performance Materials (Houston, Texas), "ZYTEL" and "MINION" from Du Pont (Wilmington, Delaware), "TROGANMID" from Evonik (Allentown, Pennsylvania), and "ULTRAMID" from BASF Corp. (Parsippany, New Jersey).

[0061] The material 400 and / or the material 510 may include a thermoplastic elastomer. For example, in applications where high stress is applied at high speed, it is preferable that the moldable polymer is a thermoplastic elastomer or includes a thermoplastic elastomer. Thermoplastic elastomers (TPEs) are defined and described in Thermoplastic Elastomers, A Comprehensive Review (Editors: N.R. Legge, G. Holden, H.E. Schroeder, 1987, Hanser Publishers, New York), the entire content of which is incorporated herein by reference. A thermoplastic elastomer is a reaction product of a low equivalent weight polyfunctional monomer and a high equivalent weight polyfunctional monomer. The low equivalent weight polyfunctional monomer has a functionality of up to about 2 and an equivalent weight of up to about 300 and can form hard segments (and crystalline hard regions or domains that bind to other hard segments) by polymerization. On the other hand, the high equivalent weight polyfunctional monomer has a functionality of at least about 2 and an equivalent weight of at least about 350 and forms flexible chains by polymerization and binds the hard regions or domains. Unlike "thermoplastic" and "elastomer" (a substance that mimics natural rubber, stretches when pulled, has high tensile strength, rapidly contracts, and almost returns to its original dimensions), when heated to a temperature above the melting point of the hard regions, a thermoplastic elastomer forms a homogeneous melt and can be processed by thermoplastic techniques such as injection molding, extrusion, and blow molding. Thereafter, upon cooling, the hard and soft regions separate again, and a material with elastomeric properties is obtained.

[0062] Commercially available thermoplastic elastomers include segmented polyester TPEs, segmented polyurethane TPEs, segmented polyamide TPEs, blends of thermoplastic elastomers and thermoplastic polymers, and ionomer TPEs.

[0063] As used herein, "segmented thermoplastic elastomer" refers to a subclass of thermoplastic elastomers based on the reaction product of a high equivalent weight polyfunctional monomer and a low equivalent weight polyfunctional monomer. These are condensation reaction products of a high equivalent weight polyfunctional monomer having at least 2 average functionality and an equivalent weight of at least about 350, and a low equivalent weight polyfunctional monomer having at least 2 average functionality and an equivalent weight of less than about 300. Segmented thermoplastic elastomers useful in the present invention include polyester TPE, polyurethane TPE, polyamide TPE, silicone elastomer / polyimide block copolymer TPE, and high and low equivalent weight polyfunctional monomers appropriately selected to produce the corresponding TPEs are used.

[0064] Segmented TPEs preferably contain a "chain extender", which is usually a low molecular weight compound having an equivalent weight of less than 300. This compound has an active hydrogen functionality of about 2 - 8 and is known in the TPE art. Particularly preferred examples include ethylenediamine and 1,4 - butanediol.

[0065] "Ionomeric thermoplastic elastomers" refers to a subclass of thermoplastic elastomers based on ionic polymers (ionomers). Ionomeric thermoplastic elastomers are composed of two or more flexible polymer chains joined at multiple positions by ionic bonds or clusters. Ionomers are usually produced by copolymerization of a functionalized monomer and an olefinically unsaturated monomer, or by direct functionalization of a pre - formed polymer. Carboxyl - functionalized ionomers are obtained by direct copolymerization by free - radical copolymerization of acrylic acid or methacrylic acid with ethylene, styrene, or a similar copolymer. The resulting copolymer is generally obtained in the form of the free acid and can be neutralized to the desired extent with metal hydroxides, metal acetates, or similar salts. A review of the history of ionomers and related patents is described in Legge et al. (pp. 231 - 243).

[0066] "Thermoplastic polymer" or "TP" as used herein has a more restrictive definition than the general definition. In the general definition, it refers to "a material that softens and flows upon the application of pressure and heat." Of course, TPE meets this general definition of TP because TPE also flows upon the application of pressure and heat. Therefore, for the purposes of the present invention, it is necessary to make the definition of "thermoplastic" more specific. As used herein, "thermoplastic" means a material that flows upon the application of pressure and heat but does not have the elastic properties of an elastomer below its melting point.

[0067] Blends of TPE (thermoplastic elastomer) and TP (thermoplastic polymer) materials are also included within the scope of the present invention, thereby making it possible to further flexibly adjust the mechanical properties of the polishing filaments of the present invention. The hardness range may be 20 to 100 on the durometer Shore D.

[0068] Preferred commercially available segmented polyesters include "HYTREL 4056", "HYTREL 5526", "HYTREL 5556", "HYTREL 6356", "HYTREL 7246", "HYTREL 8238" available from E.I. Du Pont de Nemours and Company, Inc. (Wilmington, Delaware), with "HYTREL 5526", "HYTREL 5556", "HYTREL 6356" being particularly preferred. As a similar family of thermoplastic polyesters, there is one offered under the trade name "RITEFLEX" of Hoechst Celanese Corporation. Further useful polyester TPEs include "ECDEL" of Eastman Chemical Products, Inc. (Kingsport, Tennessee), "ARNITEL" of DSM Engineered Plastics, and "BEXLOY" of Du Pont. Other useful polyester TPEs include "LUBRICOMP" of SABIC (Exton, Pennsylvania), and those containing lubricants, glass fiber reinforcement, and carbon fiber reinforcement are commercially available.

[0069] Commercially available segmented polyamides include "PEBAX" and "RILSAN" offered by Arkema (King of Prussia, Pennsylvania).

[0070] Commercially available segmented polyurethanes include "ESTANE" offered by Lubrizol (Brecksville, Ohio). Other segmented polyurethanes include "PELLETHANE" and "ISOPLAST" offered by The Dow Corning Company (Midland, Michigan), and "ELASTOLLAN" offered by BASF Corporation.

[0071] Thermoplastic elastomers are further described in U.S. Patent No. 5,427,595 (Pihl et al.), which is assigned to the assignee of the present application, and the entire content thereof is incorporated herein by reference.

[0072] FIG. 6 shows a method of forming a polishing article in accordance with an embodiment of the present specification. Method 600 may be used to create any of the polishing articles 10 shown in FIGS. 1-3.

[0073] In block 610, a hub is formed. The hub may be formed from a hub material 612, which may be any suitable polymeric material such as a thermoplastic polymer, a thermosetting polymer, a thermoplastic elastomer, etc.

[0074] The hub material 612 may be formed, for example, using a mold. As shown in block 614, the material 612 is heated to a molten or semi-molten state and then moved into the mold. The material 612 may be supplied into the mold by injection molding, extrusion molding, or other methods. For example, a shearing force 616 may be applied by an extruder. The hub is then cooled so that it can be removed from the mold. Other steps 618 may also be included, such as mixing of components for forming the hub material 612 and other steps.

[0075] In block 620, an elongated component (e.g., brush bristles) is formed. The brush bristle material 622 may include any suitable polymer or resin material mixed with abrasive particles. As described herein, the abrasive particles may be crushed, formed, shaped, or other suitable abrasive particles. As shown in block 624, the material 622 may be heated. Also, as shown in block 626, shear force may be applied using an extruder. Other processes 628 may also be performed, for example, the abrasive particles may undergo a process of alignment 632 or orientation 634. For example, an electrostatic or magnetic alignment process can be used as described in the published PCT applications (WO 2018 / 080703, WO 2018 / 080755, WO 2018 / 136268, WO 2019 / 207415, WO 2019 / 207416, WO 2019 / 207417, WO 2019 / 079331, WO 2019 / 074768, and WO 2020 / 261112).

[0076] Alignment or orientation may also be achieved by depositing the elongated material as a slurry containing a liquid (e.g., in a molten or uncured state) material and abrasive particles. In this case, when extruding the slurry from the die, the liquid binder is adapted to align the abrasive particles in the direction of the liquid flow by the flow passing through the die along the flow axis. Thereafter, by cooling and / or curing the elongated material, an elongated abrasive element with the abrasive particles directionally aligned along the element axis is formed.

[0077] Alternatively, the material 622 of the elongated component may be supplied as a slurry containing a liquid (e.g., in a molten or uncured state) binder and abrasive particles. This material is injected into an elongated mold cavity, where the liquid binder is adapted to align the abrasive particles in the direction of the liquid flow by the flow passing through the elongated cavity along the flow axis. Thereafter, by cooling and / or curing the material 622, an elongated abrasive element containing the formed abrasive particles and directionally aligned along the element axis is formed.

[0078] Alternatively, the elongated component material 622 may be supplied as a slurry containing a liquid (e.g., molten or uncured) binder and abrasive particles, and deposited within the elongated mold cavity 300 if the formed abrasive particles themselves are magnetizable or have a magnetizable surface coating. The slurry deposited in this manner may be exposed to a magnetic field adapted to align the formed abrasive particles. By this method, the abrasive particles are aligned along the elongated dimension of the mold cavity (or along another dimension determined by the interaction with the magnetic field). Thereafter, the binder is cooled and / or cured to form an elongated abrasive element containing abrasive particles aligned along the element axis.

[0079] Or, the elongated component material 622 may be supplied as a slurry containing a liquid (e.g., molten or uncured) binder 220 and formed abrasive particles 200, and may be deposited within the elongated mold cavity 300. In this case as well, the abrasive particles are magnetizable or have a magnetizable surface coating. The slurry is exposed to a magnetic field adapted to align the formed abrasive particles after extrusion or while present within the mold. By this method, the abrasive particles are aligned along the elongated dimension of the resulting elongated abrasive element (or along another dimension determined by the interaction with the magnetic field). Thereafter, the binder is cooled and / or cured to form an elongated abrasive element containing abrasive particles aligned along the element axis.

[0080] Figures 7A and 7B show abrasive articles comprising elongated components according to embodiments described herein. Figure 7A shows an abrasive article 700 including a hub 710, which is composed of a first material that does not contain abrasive particles. This first material may be a more rigid or stronger material. As shown in Figure 7, the first material also extends within the brush filaments, which may thereby reduce breakage of the brush filaments.

[0081] The polishing article further includes a plurality of brush bristles 720, which are made of a second material. The second material may be a polymer or a polymer resin containing abrasive particles. The second material may extend over the entire length of the brush bristles 720, or may extend over half of the length, or may extend over other portions based on the desired properties of the final polishing article.

[0082] In some embodiments, the polishing article 700 is formed by co-injection molding, thereby forming a strong bond between the hub material 710 and the brush bristle material 720. This forms an integral bond between the brush bristles 720 and the hub 710, reducing premature breakage of the brush bristles. However, other manufacturing processes may also be appropriate. For example, in some embodiments, an overmolding process may be used. Further, in some embodiments, a chemical bond between the materials 710 and 720 may be appropriate. Also, a mechanical bond between the materials 710 and 720, such as protrusions on the material 710, a lock and key structure, or other suitable options, may be appropriate.

[0083] FIG. 7B shows a schematic view of brush bristles 750 extending from a hub 780. The hub 780 is made of a first material 760, which extends at least partially into the brush bristles 750. The brush bristles 750 have a length 752 of the brush bristles extending from the connection point 782 to the hub, measured to the end. Both the first material 760 and the second material 770 extend at least partially along the brush bristle length 752.

[0084] As shown in FIG. 7B, the first material 760 extends from the hub connection point 782 towards the end of the brush bristles 750. However, in the embodiment of FIG. 7B, the first material 760 does not extend 100% to the end of the brush bristles 750. In some embodiments, the first material 760 may extend only 10%, 20%, or 25% of the length 752. However, in other embodiments, the first material 760 may extend along substantially the entire length of the brush bristles 750, for example, over at least 80%, at least 90%, or at least 95% of the length 752. Also, in some applications, it may be appropriate for the first material 760 to extend such that it approaches the midpoint between the connection point 782 and the full length 752, for example, where the length 762 is at least 30%, at least 40%, at least 50%, at least 60%, or at least 70% of the length 752.

[0085] The second material 770 covers the length 772 of the brush bristles 750. The second material 770 contains abrasive particles. The second material 770 may contain the same or a different polymer or resin as the first material 760, and may further contain abrasive particles. The second material 770 may be bonded to the first material 760 by any suitable method such as chemical bonding, mechanical bonding, etc. The second material 770 may be deposited using overmolding, injection molding, or other suitable lamination processes on top of the first material 760. As shown in FIG. 7B, in some embodiments, the material 770 extends along a portion of the brush bristle length 752. The second material may extend over more than half of the brush bristle length 752, for example, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90%. In some embodiments, the second material 770 may actually extend along the entire brush bristle length 752 or cover a portion of the hub 780, such that the second material extends over 100% of the brush bristle length 752. However, in some embodiments, the second material 770 may cover less than half of the brush bristle length 752, for example, less than 50%, less than 40%, less than 30%, or less than 20%.

[0086] By using the multi-shot injection molding method, a radial brush disk can be manufactured that has a resin composition or properties different from the portion where the central hub extends from the brush bristles. This method can reduce costs and has the potential to create more durable products. In some prior art products, HYTREL(R) resin (provided by DUPONT(R)) is used due to its excellent flex fatigue properties. This allows the bending of the brush bristles during use without accompanying breakage. Other resin types provide higher wear resistance and excellent cutting speeds but have been shown to cause premature bristle breakage after excessive bending. In some embodiments, the central hub and the base of the brush bristles can be manufactured from different thermoplastic elastomers. For example, the hub portion and a part of each brush bristle (e.g., the brush bristle connection portion) may be formed from a flex fatigue resistant material such as polyester (e.g., HYTREL(R), etc.), and the brush bristles may be manufactured from a more durable and wear-resistant material such as polyamide (e.g., Vestamid(R), etc.). The brush bristle connection portion may extend up to at least 5%, 10%, 20%, 30%, 40%, or 50% of the length of the brush bristles.

[0087] In some embodiments, the first resin (e.g., hub-forming material without abrasive) may be softer and have higher flex fatigue resistance than the second resin. On the other hand, the second resin (e.g., brush bristle-forming material with abrasive) may have wear resistance, reinforcement, low wear, high rigidity, and higher heat resistance than the first resin.

[0088] However, both the first resin and the second resin may be manufactured from the same type of resin, or may consist of the same base material with performance improvers (e.g., lubricants, grinding aids, abrasives, and / or reinforcing materials) added. In other embodiments, the first and second materials may be selected for their respective excellent properties.

[0089] In some embodiments, the outer layer containing minerals is hard and made of wear-resistant resin, and the inner core of the brush bristles may or may not contain minerals and is made of a soft material with excellent flex fatigue characteristics. This configuration can prevent the brush bristles from breaking prematurely.

[0090] Breakage of the brush bristles often occurs at the base of the brush bristles, which is the hub connection point. By using the two-shot injection molding method, a strengthened hub and brush bristle base can be formed. In some embodiments, the hub of the brush bristle product is strengthened with a filler component. The filler may be composed of a screen, short fibers, non-woven fabric, etc.

[0091] FIG. 8 shows a lamination pattern that can be used according to the embodiments of this specification. The brush bristles may be formed using a concept obtained from the structure of a samurai sword. FIG. 8 shows lamination patterns that can be created using three different materials. In the manufacture of a samurai sword, steels with three different hardness levels, hard steel 800, medium-hard steel 810, and soft steel 820, may be used.

[0092] By laminating different types of steel, different properties can be obtained. Similarly, by using the co-injection molding method described in this specification, it may be possible to achieve more complex lamination patterns using two or more materials and manufacture abrasive articles suitable for various operations.

[0093] If the structure of the brush bristles is similar to that of a samurai sword, further performance advantages can be obtained. For example, the kobuse or wariha tetsu structure is considered to be the most useful because of its ease of manufacture, core layer, and excellent working / abrasive layer. In some embodiments, the trailing edge of the brush bristles may be reinforced with a different material than the leading edge of the tip where most of the polishing is done. The material of the trailing edge has a high elastic modulus and gives rigidity to the brush bristles, while the material of the leading edge is softer and provides a desirable finish to the workpiece.

[0094] In another structure, the trailing edge may be made of a material that is more flexible and resistant to bending fatigue, and the leading edge may be harder, more wear-resistant, and provide a high cutting rate for an RBD (Radial Bristle Disc) product.

[0095] Figure 9 shows a polishing article in operation according to an embodiment described herein. The polishing article 900 is pressed against the work surface 950 by a downward force 902. The polishing article 900 rotates with respect to the workpiece 950, and the leading edge 910 contacts the work surface 950.

[0096] In some embodiments, a comb-type radial brush disk may be manufactured using multiple injection molding. In this disk, some brush bristles contain a resin with property set 1, and the remaining brush bristles contain a resin with property set 2. Such a disk may be similar to a comb flap disk or wheel that creates flaps alternately with a coating abrasive and a non-woven abrasive. In some embodiments, the brush bristles may have different compositions alternately (or for every certain integer). For example, the properties of the resin may differ between groups of brush bristles, or the size and properties of the minerals may differ. This allows the RBD to provide a "soft" feel and excellent finish while achieving a high cutting rate and reducing the end-user's process steps.

[0097] In some embodiments, the stiffness of the fibers may vary along the length, and the stiffness may be higher at the hub connection end of the brush bristles. Such a structure may be useful for detecting the end of the RBD life within a robot cell. When the length of the brush bristles shortens due to wear, the stiffness increases. The robot polishing system can detect this change in stiffness through a strain gauge or the like and recognize the timing for replacement with a new product, or the timing for adjustment to perform more optimal polishing, such as an increase in RPM or an adjustment of the force.

[0098] In some embodiments, the first and second resin types are selected to have different heat shrinkage rates, which may induce a curved shape in the brush filaments. Similarly, in some embodiments, the brush filaments may be formed to curl, and as the polishing article cools, three-dimensional brush filaments curved in multiple planes may be formed.

[0099] In some embodiments, the brush filaments may be formed with one or more annular reinforcing portions. The annular reinforcing portion may be disposed along the length of the brush filament, for example, at a position a distance X from the tip. The annular reinforcing portion may be, for example, helical. By varying the elasticity of the annular reinforcing portion, the adaptability of the brush filament to bending may be adjustable.

[0100] By using the techniques described herein, polishing articles with brush filaments having various shapes and physical properties can be formed. For example, the polishing article may have brush filaments that include a material for indicating the end of life. This may use various mechanisms such as sound, vibration, color, electrical continuity, heat, etc., which are described in U.S. Provisional Patent Applications (Serial Nos. 63 / 366802, 63 / 366803, and 63 / 366806, all filed on June 22, 2022).

[0101] In some embodiments, the surface conditioning article described herein may include properties that induce breakdown at specific locations of the brush filaments. This may include notches provided in the sidewalls of the formed brush filaments, fine or coarse textures at specific locations along the length of the brush filament portion mold, or one or more slits or cuts.

[0102] Depending on the shape, position, and size of the introduced features, breakdown of the brush filaments may occur without complete failure of the surface conditioning article. When the brush filaments contain polishing particles, new minerals may be exposed by the breakdown, and the profile of the formed part may be refreshed.

[0103] In addition to the case where the induced features are formed on the brush bristles, it is also explicitly envisioned that after the initial forming process, laser treatment, surface treatment, die cutting, and other secondary treatments are applied to the formed surface conditioning article.

[0104] In some embodiments, microreplication or specific mold textures may be included, which can improve the flow and solidification of the polymer and may eliminate or reduce knit lines and flow fronts.

[0105] In some embodiments, the abrasive article may be formed using insert molding. For example, it may be achieved by introducing a sheet material containing minerals (such as films, non-woven fabrics, etc.) into a mold cavity, closing the mold, and molding resin around it. In this case, the resin may be introduced from one side or multiple sides.

[0106] Furthermore, although many examples describe being formed using co-injection molding, in some embodiments, overmold molding is used, and it is explicitly envisioned that brush bristles with multiple resin layers can be obtained. For example, after the first resin is injected into the mold, the second resin may be injected over the first resin over a specific area or the entire part. In some embodiments, highly reflective polymers are used for the hub forming material or the brush bristle forming material. Such abrasive articles, when used in combination with a light source, can better illuminate the workpiece during polishing. The highly reflective polymer is included as an additive, and the hub forming material or the brush bristle forming material may be a mixture. For example, metal powders and particles (such as titanium oxides) can be added. Also, glass powder may improve reflectivity. Reflective thermoplastic polyurethane elastomers may also have reflective properties.

[0107] In this specification, a single polishing article 10 is described, for example, as shown in FIGS. 1, 7A, and 9. However, it is explicitly contemplated that a plurality of polishing articles 10 may be stacked to form a brush.

[0108] Article 10 may include attachment means as shown, for example, in U.S. Patent No. 5,903,951. For example, a plurality of articles may be joined to form an assembly, or one or more articles 10 may be attached to a support means such as another hub or shaft as described therein. Hub 22 may have an inner edge configured to engage a shaft, or alternatively (or in addition) may include attachment holes for receiving one or more locking rods. Hub 22 may also include grooves or keyways configured for a suitably configured key to engage within the shaft. Further, hub 22 may be continuous and may not include an opening defined by the inner edge. Attachment means may be provided at the center of hub 22. This type of attachment means is suitable for a 360° circular article. Suitable attachment means are described in U.S. Patent Nos. 3,562,968, 3,667,170, 3,270,467, the entire contents of which are incorporated herein by reference. One preferred attachment means is an integrally molded threaded stud adapted for a screw type engagement with a rotary tool as described in U.S. Patent No. 3,562,968. In such an embodiment, it is preferred that the attachment means is molded integrally with hub 22 and is centered with respect to hub 22 for proper rotation of article 10. The attachment means may be made of the same material as the remainder of article 10 and may include abrasive particles. Alternatively, the attachment means may be made by injection of a separate binder 220, with or without abrasive particles.

[0109] In other embodiments, a hook and loop type attachment mechanism is provided on the hub 22, and the article 10 may be attached to the backup pad of a power rotary tool. Suitable hook and loop fasteners include those described in U.S. Patent No. 5,077,870, "Mushroom-Type Hook Strip for Mechanical Fasteners" (Melbye et al.) (incorporated herein by reference), and SCOTCHMATE® commercially available from 3M Company (St. Paul, Minnesota). Also, it is possible to use hermaphroditic fasteners such as DUAL LOCK® fasteners commercially available from 3M Company to secure the shaped article to the backup pad. Further, it is possible to use mating structural surfaces such as those described in U.S. Patent No. 4,875,259, "Engageable Articles" (Appeldorn) (incorporated herein by reference).

[0110] Within the scope of the present invention, it also includes using an attachment system that includes a layer of pressure-sensitive adhesive on either the hub of the shaped article or the backup pad of the driving tool, and the other article or backup pad has a surface to which the pressure-sensitive adhesive adheres removably with a desired adhesive strength. Examples of suitable pressure-sensitive adhesives include acrylic polymers and copolymers such as latex crepe, rosin, polybutyl acrylate, and polyacrylate esters, vinyl ethers such as polyvinyl n-butyl ether, alkyd adhesives, natural rubber, synthetic rubber, chlorinated rubber, and rubber-based adhesives such as mixtures thereof. The adhesive is selected to provide the desired adhesive properties. One preferred surface to which the abrasive article is removably fixed is a vinyl sheet.

[0111] Also, it is possible to provide one or more straight or threaded holes or openings in the hub of the shaped article. Thereby, the abrasive article can be mechanically fixed to the backup pad with bolts, nuts, etc. In such holes, inserts of materials different from the central portion of the shaped article may be attached.

[0112] In some embodiments, there may be provided a mating attachment mechanism within each hub material. This mechanism allows the abrasive articles 10 to be stacked and the formed brush filament layers to be integrated to create a brush. The mating mechanism allows the brush to be rotated as a unit. During acceleration and deceleration, large forces can be applied to the individual brush filaments. By creating an alternative coupling mechanism, it may be possible to adjust local forces by coupling the brush filament plate during rotation to resist the working portion and releasing the coupling during deceleration.

[0113] Other abrasive brush, brush filament, and / or filament configurations are described, for example, in the following U.S. patents: Patent Nos. 5,045,091 (Abrahamson et al.), 5,233,719 (Young et al.), 5,400,458 (Rambosek), 5,679,067 and 5,903,951 (Ionta et al.), 5,427,595 (Pihl et al.), 5,460,883 (Barber et al.), 3,618,154 (Muhler et al.), and 3,233,272 (Pambello).

[0114] Abrasive particles generally include crushed abrasive particles, shaped abrasive particles, and / or precision shaped abrasive particles. Examples of basic shaped abrasive particles are described in U.S. Patent Nos. 5,201,916 (Berg et al.) and 5,366,523 (Rowenhorst et al.), and it is generally disclosed that these particles can be used in abrasive brushes. Examples of precision shaped abrasive particles include CUBITRON II® provided by 3M Company (St. Paul, Minnesota). Examples of precision shaped abrasive particles are also described in U.S. Patent Nos. 8,142,531 (Adefris et al.) and 8,728,185 (Adefris), and it is generally disclosed that these particles can be used in abrasive brushes. Other useful shaped abrasive particles are disclosed in U.S. Provisional Patent Application No. 62 / 669,568 (Mevissen et al., "Abrasive Articles Containing Soft Shaped Abrasive Particles"), the content of which is incorporated herein by reference.

[0115] Although the present invention has been described based on specific embodiments, it should be understood that these embodiments are illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the methods and apparatuses of the present invention without departing from the spirit and scope of the invention. Accordingly, the present invention is intended to cover modifications and variations within the scope of the appended claims and their equivalents.

[0116] Surface conditioning articles are proposed, which include a hub portion using a first material. This first material does not contain abrasive particles. Also, the article includes a plurality of elongated abrasive elements, each extending along an element axis, and each of these primary elongated abrasive elements contains a second material.

[0117] The surface conditioning article can be implemented such that the second material contains a plurality of abrasive particles.

[0118] The surface conditioning article can be implemented such that the abrasive particles are crushed abrasive particles, shaped abrasive particles, partially shaped abrasive particles, precision shaped abrasive particles, or fragments of abrasive particles.

[0119] The surface conditioning article can be implemented such that the first material contains a polymer and the second material also contains that polymer.

[0120] The surface conditioning article can be implemented such that the first material contains a first polymer and the second material contains a second polymer different from the first polymer.

[0121] The surface conditioning article can be implemented such that the first material or the second material contains a filler.

[0122] The surface conditioning article can be implemented such that the filler includes a screen, fiber, particle, non-woven material.

[0123] The surface conditioning article can be implemented such that the plurality of elongated elements also contain a third material.

[0124] The surface conditioning article can be implemented such that each of a plurality of elongated elements includes a first material and a second material is bonded to the first material.

[0125] The surface conditioning article can be implemented such that the second material is overmolded onto the first material.

[0126] The surface conditioning article can be implemented such that the second material is injection molded onto the first material.

[0127] The surface conditioning article can be implemented such that the second material is chemically or mechanically bonded to the first material.

[0128] The surface conditioning article can be implemented such that each elongated element has a length and the first material has a length that is shorter than its length.

[0129] The surface conditioning article can be implemented such that each elongated element has a length and the second material has a length that is shorter than its length.

[0130] The surface conditioning article can be implemented such that the length of the second material exceeds 50% of the total length.

[0131] The surface conditioning article can be implemented such that the second material is tougher than the first material.

[0132] The surface conditioning article can be implemented such that the second material has a higher durometer than the first material.

[0133] The surface conditioning article can be implemented such that the first material is polyester and the second material is polyamide.

[0134] The surface conditioning article can be implemented such that the first material has a first rigidity, the second material has a second rigidity, and the first rigidity is different from the second rigidity.

[0135] The surface conditioning article can be implemented such that a first material has a first glass transition temperature, a second material has a second glass transition temperature, and the first glass transition temperature is different from the second glass transition temperature.

[0136] The surface conditioning article can be implemented such that a first material has a first melting point, a second material has a second melting point, and the first melting point is different from the second melting point.

[0137] The surface conditioning article can be implemented such that the stiffness of each elongate element varies along its length.

[0138] The surface conditioning article can be implemented such that the hub stiffness at the hub connection point is higher than the stiffness of the tip opposite the hub connection point.

[0139] The surface conditioning article may be implemented such that the plurality of elongate elements are a first plurality of elongate elements, and the surface conditioning article further includes a second plurality of elongate elements each including a third material different from the second material.

[0140] The surface conditioning article can be implemented such that the third material includes a second group of abrasive particles different from the first group of abrasive particles.

[0141] The surface conditioning article can be implemented such that the third material includes a third polymer different from the second polymer of the second material.

[0142] The surface conditioning article can be implemented such that each elongate element has a leading edge that includes a leading edge material having a first modulus of elasticity, and a trailing edge that includes a trailing edge material having a second modulus of elasticity, and the second modulus of elasticity is higher than the first modulus of elasticity.

[0143] The surface conditioning article can be implemented such that each elongate element has a leading edge that includes a leading edge material, a trailing edge that includes a trailing edge material, and the second material is softer than the first material.

[0144] The surface conditioning article can be implemented such that the first and second materials include components selected from the group consisting of thermoplastic polymers, thermosetting polymers, and thermoplastic elastomers.

[0145] The surface conditioning article can be implemented such that the hub includes a hub axis.

[0146] The surface conditioning article can be implemented such that a plurality of primary elongate elements extend radially from the hub.

[0147] The surface conditioning article can be implemented such that a plurality of primary elongate elements extend axially from the hub generally parallel to the hub axis.

[0148] The surface conditioning article can be implemented such that a portion of the plurality of primary elongate elements extend axially from the hub generally parallel to the hub axis and a portion of the plurality of primary elongate elements extend radially from the hub.

[0149] The surface conditioning article can be implemented such that a portion of the plurality of primary elongate elements extend radially and axially from the hub.

[0150] The surface conditioning article can be implemented such that the article includes a brush and the plurality of elongate elements are bristles of the brush.

[0151] The surface conditioning article can be implemented such that the article includes a rotary brush and the plurality of elongate elements are bristles of the rotary brush.

[0152] The surface conditioning article can be implemented such that one or more of the elongate elements include an end-of-life indicator.

[0153] The surface conditioning article can be implemented such that the end-of-life indicator includes an indication that represents a portion of the remaining useful life.

[0154] The surface conditioning article can be implemented such that the elongate elements include breakage characteristics.

[0155] The surface conditioning article can be implemented to have fracture characteristics including notches, textured surfaces, slits, etching, or a diameter smaller than the average diameter of the elongated elements.

[0156] A method of forming a polishing article is presented, the method including filling a first mold with a first material such that the first material forms a hub within the first mold. The method also includes filling a second mold with a second material such that the second material forms a plurality of elongated polishing elements extending from the hub. The method further includes curing a mixture such that the elongated polishing elements are bonded to the hub and the second material is bonded to the first material. The first material does not include abrasive particles and the second material includes abrasive particles.

[0157] The method can be implemented such that the first mold is the same as the second mold and the second material is injected first, followed by injection of the first material.

[0158] The method can be implemented such that the first material is injected while the second material remains in a flowable state.

[0159] The method of flowing the first material into the first mold can be implemented to include heating the first material and flowing it into the first mold.

[0160] The method can be implemented such that the first mold includes a cavity having a negative shape of the hub and a plurality of extension features, the first material forms an integral body including the hub and the plurality of extension features, and the second material coats at least a portion of the plurality of extension features within the second mold.

[0161] The method can be implemented such that each of the elongated polishing elements has an element length extending from a hub connection point to a tip opposite the hub connection point, and each of the plurality of extension features has a feature length that is shorter than the element length.

[0162] This method can be implemented such that the characteristic length is less than 50% of the element length.

[0163] This method can be implemented such that the characteristic length is 50% or more of the element length.

[0164] This method can be implemented such that the second material covers each coating length of the elongated abrasive element, the coating length is measured from the tip towards the hub connection point, and the coating length is shorter than the element length.

[0165] This method can be implemented such that the coating length is less than 80% of the element length.

[0166] This method can be implemented such that the coating length is less than 50% of the element length.

[0167] This method can be implemented such that the first material has a first rigidity, the second material has a second rigidity, and the first and second rigidities are different.

[0168] This method can be implemented such that the first material includes a filler.

[0169] This method can be implemented such that the filler includes a non-woven material, short fibers, or a scrim.

[0170] This method can be implemented such that the second material includes a first component and a second component, the first component forms a leading edge, and the second component forms a trailing edge.

[0171] This method can be implemented such that the second component has a higher elastic modulus than the first component.

[0172] This method can be implemented such that the second component is softer than the first component.

[0173] This method can be implemented such that the first component is more wear-resistant than the second component.

[0174] This method can be implemented such that the rigidity of the elongated polishing element varies from the tip towards the hub connection point.

[0175] This method can be implemented such that the plurality of elongated polishing elements are the first plurality of elongated polishing elements, and further includes filling a third mold with a third material, and the third material forms a second plurality of elongated polishing elements extending from the hub.

[0176] This method can be implemented such that the third mold is the same as the second mold and the second material and the first material flow in substantially simultaneously.

[0177] This method can be implemented such that the second material has different properties from the third material.

[0178] This method can be implemented such that the first material and the second material include components selected from the group consisting of thermoplastic polymers, thermosetting polymers, and thermoplastic elastomers.

[0179] This method can be implemented such that the first material or the second material includes an end-of-life indicator.

[0180] This method can be implemented such that the end-of-life indicator includes a display indicating a part of the remaining useful life.

[0181] This method can be implemented such that the second mold includes fracture characteristics.

[0182] This method can be implemented such that the fracture characteristics impart a surface texture to the elongated element.

[0183] This method can be implemented such that the surface texture is a notch, a depression, a slit, or a limited diameter.

Claims

1. A surface conditioning article comprising: a hub portion, said hub portion comprising a first material, said first material being free of abrasive particles, and a plurality of elongated abrasive elements, each elongated abrasive element extending along an element axis, each of said primary elongated abrasive elements comprising a second material. The surface conditioning article as described above.

2. The surface conditioning article of claim 1, wherein said second material comprises a plurality of abrasive particles.

3. The surface conditioning article of claim 1 or 2, wherein said first material comprises a polymer and said second material also comprises a polymer.

4. The surface conditioning article of any one of claims 1 to 3, wherein said first material comprises a first polymer and said second material comprises a second polymer different from said first polymer.

5. The surface conditioning article of any one of claims 1 to 4, wherein said first material or said second material comprises a filler.

6. The surface conditioning article of any one of claims 1 to 5, wherein said plurality of elongated elements further comprises a third material.

7. The surface conditioning article of any one of claims 1 to 6, wherein each of said plurality of elongated elements comprises said first material and said second material is bonded to said first material.

8. The surface conditioning article of claim 7, wherein each of said plurality of elongated elements has a length and said first material has a first material length shorter than said length.

9. The surface conditioning article of any one of claims 1 to 8, wherein said second material is tougher than said first material.

10. The surface conditioning article of any one of claims 1 to 9, wherein said second material has a higher durometer than said first material.

11. The surface conditioning article of any one of claims 1 to 10, wherein said first material is polyester and said second material is polyamide.

12. The surface conditioning article of any one of claims 1 to 11, wherein said first material has a first rigidity, said second material has a second rigidity, and said first rigidity is different from said second rigidity.

13. The surface conditioning article of any one of claims 1 to 12, wherein said first material has a first glass transition temperature, said second material has a second glass transition temperature, and said first glass transition temperature is different from said second glass transition temperature.

14. The surface conditioning article according to any one of claims 1 to 13, wherein the rigidity of each of the elongated elements varies along the length of the elongated element.

15. The surface conditioning article according to claim 14, wherein the hub rigidity at the hub connection point is higher than the tip rigidity on the opposite side of the hub connection point.

16. The plurality of elongated elements are a first plurality of elongated elements, and the surface conditioning article further includes a second plurality of elongated elements, each including a third material different from the second material, the third material including a second plurality of abrasive particles different from the first plurality of abrasive particles. The surface conditioning article according to any one of claims 2 to 15, wherein the third material includes a second plurality of abrasive particles different from the first plurality of abrasive particles.

17. Each of the elongated elements has a tip edge including a tip material having a first modulus and a rear edge including a rear material having a second modulus, and the second modulus is higher in rigidity than the first modulus. The surface conditioning article according to any one of claims 1 to 16.

18. Each of the elongated elements has a tip edge including a tip material and a rear edge including a rear material, and the second material is softer than the first material. The surface conditioning article according to any one of claims 1 to 17.

19. The surface conditioning article according to claim 1, wherein a part of the plurality of primary elongated elements extends radially and axially from the hub.

20. The surface conditioning article according to any one of claims 1 to 19, wherein one or more of the elongated elements further include an end-of-life indicator.

21. The surface conditioning article according to claim 20, wherein the end-of-life indicator includes an indication indicating a remaining useful life portion.

22. The surface conditioning article according to any one of claims 1 to 21, wherein the elongated element includes a failure feature.

23. The surface conditioning article according to claim 22, wherein the failure feature includes a notch, a textured surface, a slit, an etching, or a diameter smaller than an average diameter of the elongated element.

24. A method of forming an abrasive article, comprising: filling a first mold with a first material, the first material forming a hub within the first mold; filling a second mold with a second material, the second material forming a plurality of elongated abrasive elements extending from the hub. Allow the mixture to solidify, bond the plurality of elongated abrasive elements to the hub, and bond the second material to the first material, A method wherein the first material does not contain abrasive particles and the second material contains abrasive particles.

25. The method according to claim 24, wherein filling the first mold with the first material includes heating the first material and flowing the first material into the first mold.

26. The method according to claim 24 or 25, wherein the first mold includes a cavity having a negative shape of the hub and a plurality of extension features, the first material forms a unitary body including the hub and the plurality of extension features, and in the second mold, the second material coats at least a portion of each of the plurality of extension features.

27. The method according to claim 26, wherein the second material covers a coating length of each of the plurality of elongated abrasive elements, the coating length is measured from the tip toward the hub connection point, and the coating length is shorter than the element length.

28. The method according to claim 27, wherein the coating length is less than 80% of the element length.

29. The method according to claim 27, wherein the coating length is less than 50% of the element length.

30. The method according to any one of claims 24 to 29, wherein the first material includes a filler, and the filler includes a non-woven material, chopped fibers or a scrim.

31. The method according to any one of claims 24 to 30, wherein the second material includes a first component and a second component, the first component forms a tip edge, and the second component forms a rear edge.

32. The method according to any one of claims 24 to 31, wherein the rigidity of the elongated abrasive element varies from the tip to the hub connection point.

33. The plurality of elongated abrasive elements are a first plurality of elongated abrasive elements, and the method includes filling a third mold with a third material, the third material forming a second plurality of elongated abrasive elements extending from the hub, the method according to any one of claims 24 to 32.

34. The method according to claim 33, wherein the third mold is the second mold, and the steps of filling with the second material and the first material are performed substantially simultaneously.

35. The method according to claim 33, wherein the second material has properties different from those of the third material. **Claim 36** The method according to any one of claims 24 to 35, wherein the first material or the second material includes an end-of-life indicator. **Claim 37** The method according to claim 36, wherein the end-of-life indicator includes a display indicating a remaining useful life portion. **Claim 38** The method according to any one of claims 24 to 37, wherein the second mold includes a breakage feature. **Claim 39** The method according to claim 38, wherein the breakage feature provides a surface texture to the elongated element. **Claim 40** The method according to claim 38, wherein the surface texture includes a notch, a depression, a slit, or a restricted diameter.

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