WO2022221646A1 - Structures linéaires de particules abrasives alignées - Google Patents

Structures linéaires de particules abrasives alignées Download PDF

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Publication number
WO2022221646A1
WO2022221646A1 PCT/US2022/024992 US2022024992W WO2022221646A1 WO 2022221646 A1 WO2022221646 A1 WO 2022221646A1 US 2022024992 W US2022024992 W US 2022024992W WO 2022221646 A1 WO2022221646 A1 WO 2022221646A1
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Prior art keywords
abrasive particles
filament
shaped abrasive
particles
abrasive
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PCT/US2022/024992
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English (en)
Inventor
Yuyang LIU
Ernest L. Thurber
Joseph B. Eckel
Thomas J. Nelson
Mark A. LUKOWSKI
Dwight D. Erickson
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3M Innovative Properties Company
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Application filed by 3M Innovative Properties Company filed Critical 3M Innovative Properties Company
Priority to EP22789001.9A priority Critical patent/EP4323149A1/fr
Publication of WO2022221646A1 publication Critical patent/WO2022221646A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00—Materials not provided for elsewhere
    • C09K3/14—Anti-slip materials; Abrasives
    • C09K3/1409—Abrasive particles per se

Definitions

  • abrasive particles and abrasive articles including abrasive particles are useful for abrading, finishing, or grinding a wide variety of materials and surfaces in the manufacturing of goods. As such, there continues to be a need for improving the cost, performance, or life of abrasive particles or abrasive articles.
  • SUMMARY [0002] Lineal aligned abrasive particle structures are presented. The structure includes a plurality of shaped abrasive particles. Each of the shaped abrasive particles comprises a perimeter and a thickness. The perimeter of each of the shaped abrasive particles is substantially similar.
  • each of the shaped abrasive particles is substantially similar.
  • the structure also includes a filament coupled to each of the plurality of shaped abrasive particles.
  • the plurality of shaped abrasive particles are regularly spaced along the filament.
  • Lineal aligned abrasive particle structures described herein provide improved orientation of precision shaped abrasive particles in coated, bonded and nonwoven abrasive articles.
  • Lineal aligned abrasive particle structures may exhibit regular spacing, which may provide improved cutting behavior.
  • FIGS.1A-1C illustrate lineal aligned abrasive particle structures in accordance with embodiments herein.
  • FIGS. 2A and 2B are illustrative schematics of lineal aligned abrasive particle structures on a coated abrasive article in accordance with an embodiment of the present invention.
  • FIGS. 3A-3C illustrate different configurations of lineal aligned abrasive particle structures on a backing in accordance with embodiments herein.
  • FIGS.4A-4B illustrate lineal aligned abrasive particle structures in bonded abrasive articles in accordance with embodiments herein.
  • FIGS.9 illustrate lineal aligned abrasive particle structures in bonded abrasive articles in accordance with embodiments herein.
  • FIGS. 5A-5B illustrate methods of making an abrasive article in accordance with embodiments herein.
  • FIGS. 6A-6E illustrate lineal aligned particles in accordance with embodiments herein.
  • FIG. 7 illustrates a method of forming an abrasive article in accordance with embodiments herein.
  • FIG. 8 illustrates a schematic of a coated abrasive article in accordance with embodiments herein.
  • FIG. 9 illustrates a method of using an abrasive article in accordance with embodiments herein.
  • FIGS. 10-11 illustrate abrasive particles, lineal aligned abrasive particles, and abrasive articles formed in Examples.
  • the term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.
  • the term “substantially” as used herein refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.
  • shaped abrasive particle means an abrasive particle with at least a portion of the abrasive particle having a predetermined shape that is replicated from a mold cavity used to form the shaped precursor abrasive particle. Except in the case of abrasive shards (e.g. as described in US Patent Application Publication Nos. 2009/0169816 and 2009/0165394), the shaped abrasive particle will generally have a predetermined geometric shape that substantially replicates the mold cavity that was used to form the shaped abrasive particle. Shaped abrasive particle as used herein excludes abrasive particles obtained by a mechanical crushing operation.
  • geometric shapes having at least one vertex include polygons (including equilateral, equiangular, star-shaped, regular and irregular polygons), lens- shapes, lune-shapes, circular shapes, semicircular shapes, oval shapes, circular sectors, circular segments, drop-shapes and hypocycloids (for example super elliptical shapes).
  • geometric shapes are also intended to include regular or irregular polygons or stars wherein one or more edges (parts of the perimeter of the face) can be arcuate (either of towards the inside or towards the outside, with the first alternative being preferred).
  • triangular shapes also include three- sided polygons wherein one or more of the edges (parts of the perimeter of the face) can be arcuate.
  • the second side may comprise (and preferably is) a second face.
  • the second face may have a perimeter of a second geometric shape.
  • shaped abrasive particles also include abrasive particles comprising faces with different shapes, for example on different faces of the abrasive particle.
  • Some embodiments include shaped abrasive particles with different shaped opposing sides.
  • the different shapes may include, for example, differences in surface area of two opposing sides, or different polygonal shapes of two opposing sides.
  • shaped abrasive particles also include abrasive particles with openings, for example an open hole in the central of the shaped abrasive particles.
  • abrasive particles with openings for example an open hole in the central of the shaped abrasive particles.
  • Examples of shaped abrasive grains with open structures were described in U.S. Pat. No.8,142,532 (Erickson, et al).
  • the shaped abrasive particles are typically selected to have an edge length in a range of from 0.001 mm to 26 mm, more typically 0.1 mm to 10 mm, and more typically 0.5 mm to 5 mm, although other lengths may also be used.
  • the shaped abrasive particle may have a “sharp portion” which is used herein to describe either a sharp tip or a sharp edge of an abrasive article.
  • the sharp portion may be defined using a radius of curvature, which is understood in this disclosure, for a sharp point, to be the radius of a circular arc which best approximates the curve at that point.
  • the radius of curvature is understood to be the radius of the curvature of the profile of the edge on the plane perpendicular to the tangent direction of the edge. Further, the radius of curvature is the radius of a circle which best fits a normal section, or an average of sections measured, along the length of the sharp edge.
  • FIGS.1A-1C illustrate lineal aligned abrasive particle structures in accordance with embodiments herein.
  • “lineal aligned abrasive particle structures” refer to a plurality of abrasive particles coupled together by, or to, a connecting filament.
  • the connecting filament may be a compliant or rigid filament and may be coupled to the abrasive particles during particle formation or after firing.
  • the filament may be coupled directly to the abrasive particles, such as a hot-melt filament applied to the abrasive particles before curing, or fastened to the abrasive particles, using an adhesive. Illustrated in FIGS. 1A-1C are triangular precision shaped abrasive particles. However, it is expressly contemplated that other shapes of precision shaped abrasive particles are possible, so long as they can couple to a filament. [0027]
  • Lineal aligned abrasive particle structures 100 as illustrated in FIG. 1A, include precision shaped abrasive particles 102 connected to each other by a filament 104. In the embodiment of FIG. 1A, filament 104 extends through each a face of each particle 102.
  • FIG. 1A illustrates another example of lineal aligned abrasive particle structures 110.
  • a plurality of abrasive particles 112 are coupled by a filament 114.
  • Each particle 112 is at an angle 116 with respect to filament 114.
  • Angle 116 may be substantially similar for each particle 112, in some embodiments.
  • a first and second particle 112 are separated by space 118a while a third and a fourth particle 112 are separated by a space 118b.
  • Spaces 118a and 118b may be the same, in some embodiments, or different, in other embodiments. Spaces 118a and 118b may be set during formation of lineal aligned abrasive particle structures 110, as described below with respect to FIGS.5-6.
  • FIG. 1C illustrates lineal aligned abrasive particle structures 120 that include a plurality of particles 122 joined to a filament 124. Each particle 122, as illustrated in FIGS.1A-1C, can couple to a filament along, or through, a face 132, along an edge 134, or at a vertex 136.
  • Designing abrasive particles with improved cutting ability has been a goal in the abrasive industry for decades.
  • Lineal aligned abrasive particle structures provide shaped abrasive particles in a form that allows for easier alignment. Particle size correlates to the ease of alignment. The smaller the particle size, the more difficult alignment becomes. However, lineal aligned abrasive particle structures 100, 110 and 120 are all easier to align than individual particles 102, 112 or 122 because they behave like a particle larger in size. [0032] Individual abrasive particles are oriented with respect to adjacent particles and, as illustrated, are coplanar.
  • each abrasive particle is aligned such that faces of adjacent particles are parallel.
  • Orientation of abrasive particles is particularly important for the efficacy of an abrasive article.
  • a shaped abrasive particle may have a sharp tip or a sharp edge that should be oriented away from a backing material. Sharp edges, as discussed in greater detail below, may have a preferred abrading orientation and may have different abrading properties depending on whether a cutting surface is leading or trailing during an abrading operation.
  • Orientation of the abrasive particles in coated abrasive articles generally has an influence on abrading properties.
  • the abrasive particles are precisely-shaped (e.g., into triangular platelets or conical particles)
  • this effect of orientation can be especially important as discussed in U. S. Pat. Appl. Publ. No.2013/0344786 A1 (Keipert), incorporated by reference herein.
  • Lineal abrasive particles described herein provide improved ease of alignment because they behave like a particle with a structure the length of the filament 124 and the width of a particle face 132, referring to FIG.1C instead of a particle with the thickness of edge 134 and the length of particle 132.
  • agglomerate particles which have individual abrasive particles oriented to each other in three dimensions.
  • Agglomerate particles often comprised of abrasive particles within a binder structure, are often used where it is desired to have multiple sharp tips available during an abrasive operation. As the overall agglomerate structure wears away, new abrasive particles, and new tips are made available for abrading. However, generally abrasive particles are randomly oriented within an agglomerate structure.
  • lineal aligned abrasive particle structures using methods and systems described in greater detail herein, allow for tailoring of individual particle orientation, and particle- particle spacing, based on an application.
  • a filament connecting abrasive particles within the structure of lineal aligned abrasive particle structures can be made of a variety of materials depending on a desired operation.
  • a stiff filament such as ceramic, glass, etc.
  • more flexible or compliant materials can be used, such as nylon, polyester, rubber, etc.
  • a filament is made of a material that will melt, sublime or otherwise change form during an abrasive article’s formation, after placement of the lineal aligned abrasive particle structures. For example, there are many considerations in the bonded abrasive article space that may be addressed using lineal abrasive articles, as described in greater detail with regard to FIGS.4A-4B.
  • fibers that may be suitable include natural fibers, synthetic fibers, and mixtures of natural and/or synthetic fibers.
  • synthetic fibers include those made from polyester (e.g., polyethylene terephthalate), nylon (e.g., nylon-6,6, polycaprolactam), polypropylene, acrylonitrile (e.g., acrylic), rayon, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymer, and vinyl chloride-acrylonitrile copolymer.
  • suitable natural fibers include cotton, wool, jute, and hemp.
  • the fiber may be of virgin material or of recycled or waste material, for example, reclaimed from garment cuttings, carpet manufacturing, fiber manufacturing, or textile processing.
  • the fiber may be homogenous or a composite such as a bicomponent fiber (e.g., a co-spun sheath-core fiber).
  • the fibers can be tensilized and crimped staple fibers.
  • a solution is needed that allows for more easy alignment of shaped particles.
  • the solution should also be able to orient precision shaped abrasive particles as needed based on particle geometry (such as with a forward to backward tilt to achieve a desired rake angle), intended abrasive article (such as compliant or rigid filament).
  • Lineal aligned abrasive particle structures described herein allow for tailored placement and alignment of shaped abrasive particles on or within an abrasive article.
  • FIGS. 2A-2B are illustrative schematics of lineal aligned abrasive particle structures on a coated abrasive article in accordance with an embodiment of the present invention.
  • the larger size of lineal aligned abrasive particle structures 220 may make it easier to align them on a backing 210 to form a coated abrasive article 200.
  • the coated abrasive article 200 may have any suitable material for backing 210 depending on an abrasive application. While a belt is illustrated in FIGS. 2A-2B, it is expressly contemplated that other abrasive articles are possible, including abrasive discs, pads, etc.
  • Lineal aligned abrasive particle structures 220 are each composed of a plurality of abrasive particles 224 coupled together by a filament 222. Filament 222 may coupled directly to each of particles 224, or may be coupled using adhesive.
  • an abrasive article 250 may be used in a first direction 252 as well as in a second direction 254. For at least some abrasive particles, an abrading efficiency may differ if used in a first direction as opposed to a second direction.
  • a benefit to using lineal aligned abrasive particle structures 220 is that, once placed, abrasive particle tips are exposable and available for abrading.
  • methods of forming lineal aligned abrasive particle structures also provide structures with regular spacing between particles. In some embodiments, spacing between adjacent particles may be substantially similar. In other embodiments, there may be channels built in between at least some abrasive particles, potentially for swarf removal or lubricant provision. However, at least some lineal aligned abrasive particle structures 220 will have the same particle spacing as each other. [0044] FIGS.
  • FIG. 3A-3C illustrate different configurations of lineal aligned abrasive particle structures on a backing in accordance with embodiments herein.
  • FIG. 3A illustrates a coated abrasive article 300 that alternates lineal aligned abrasive particle structures 310 with crushed abrasive particles 304 on a backing 302.
  • precision shaped abrasive grains can provide higher cut rate than crushed grain, the improvement diminishes as the percentage of precision shaped abrasive grain increases. Adding crushed grain can reduce cost and also provide robustness and shelling resistance.
  • crushed grain may also help retain orientation of individual shaped abrasive particles in embodiments where a filament is made of a material that can dissolve, vaporize, melt or sublime in an oven. Crushed grain applied after particle structures 310 are laid on a backing may fall between individual abrasive particles and maintain orientation after a filament is gone.
  • FIG.3B illustrates a coated abrasive article 320 with lineal aligned abrasive particle structures 330 on a backing 322. Structures 330 are lined such that each is angled with respect to the next. Connecting a series of precision shaped abrasive particles with a filament causes structures 330 to behave like a macro structure.
  • FIG.3C illustrates another coated abrasive article 350 with lineal aligned abrasive particle structures 360 and 370 placed at angles with respect to each other. As illustrated by FIGS. 3A-3C, placement of lineal aligned abrasive particle structures can be done in a variety of patterns, with or without crushed grain or other abrasive particles. [0049] Discussed herein thus far are the use of lineal aligned abrasive particle structures in coated abrasive articles.
  • Lineal aligned abrasive particle structures described herein can be used in other abrasive articles, and may provide specific benefits in the bonded abrasive article space.
  • Lineal aligned abrasive particle structures, as described herein are composed of a filament coupled to a plurality of shaped abrasive particles.
  • the filament can be made from any number of suitable materials.
  • Nextel fibers may be useful in bonded abrasive articles because they do not experience significant volume change. Additionally, filaments that survive the bonded abrasive article processing still attached to the abrasive particles may be useful in maintaining the structure of the abrasive article.
  • bonded abrasive wheels include one or more scrim layers that are used to hold the wheel together. Scrims are known to provide resistance to a wheel breaking a part but provide a detriment to abrasive performance. In some embodiments, filaments can provide a similar function to a scrim, as illustrated in FIG.4B. [0051] Orienting abrasive particles within a bonded matrix can be difficult, as generally a mixture of abrasive particles and a bonding precursor are mixed and cured under pressure and temperature. During that process, abrasive particles in an initial orientation may be forced into a second orientation.
  • FIGS.4A-4B illustrate lineal aligned abrasive particle structures in bonded abrasive articles in accordance with embodiments herein.
  • FIG.4A illustrates a lineal aligned abrasive particle structure 400, composed of a plurality of abrasive particles 402 coupled to a filament 404. As illustrated in FIG.4A, particles 402 are substantially coplanar to each other, however they may not be linear in arrangement as filament 404 may be flexible or curved.
  • FIG.4B illustrates a cutaway view of a portion of a bonded abrasive article 420.
  • lineal aligned abrasive particle structures 400 may be coplanar, causing filaments 404 to provide internal structure to the bonded abrasive structure, acting similarly to a scrim.
  • filaments 404 are made of a material designed to melt during the bond formation process.
  • filaments 404 may be glass fibers that, during formation of a vitreous bond, melt into and form part of the vitreous bond matrix.
  • filaments 404 may be a polymeric or other material that melts into and forms a resin bond matrix in a resin bonded abrasive article.
  • Another issue in bonded abrasive construction is the introduction of porosity throughout the structure.
  • Naphthalene is a known compound that sublimes out during the bond formation process.
  • naphthalene is a known carcinogen. It is desired to find alternative methods and compounds for the introduction of pores within a bonded abrasive structure, such as wheel 420.
  • a filament 404 may be made of a material that sublimes out of the structure, leaving voids of similar structure and shape behind.
  • lineal aligned abrasive particle structures 400 may provide better abrasive particle spacing and orientation within a bonded structure. Additionally, lineal abrasive particle structures 400 may be tailored to suit needs of a particular bonded abrasive article product, for example with a longer length and filament 404 that will survive processing and perform like a scrim.
  • FIGS. 5A-5B illustrate schematics of making lineal aligned abrasive particle structures in accordance with embodiments herein. As described herein, lineal aligned abrasive particle structures are composed of a plurality of abrasive particles coupled to a filament. [0059] FIG.
  • FIG. 5A illustrates an example method 500 of making a lineal aligned abrasive particle structure.
  • a tool 502 is provided.
  • the tool has multiple cavities 504 that can receive an abrasive particle 506.
  • the cavities 504 are sized such that the abrasive particles 506 are received in a specific orientation and with a specific spacing between adjacent particles 506.
  • abrasive particles 506 fill more cavities 504 of tool 502. While FIG. 5B illustrates every cavity being full, it is expressly contemplated that only 70% of cavities 504 may be full, or only 80% or only 90% or only 95% may be full. In some embodiments, significantly fewer cavities are filled, e.g. only 30%, or 40% or 50%.
  • a spacing such as spacing 512a, 512b, or 512c.
  • Spacings 512a, 512b and 512c may be substantially the same, in some embodiments, or may differ. For example, it may be desired to have different spacing based on how a final abrasive article might be used. For example, it may be desired to build in extra spacing for debris removal or lubricant provision. For example, a spacing 512a may be up to 50% wider, or up to 100% wider, or up to 200% wider than spacing 512b.
  • an applicator 524 deposits a filament 522 on abrasive particles 506 within tool 502.
  • Filament 522 is illustrated as being printed by applicator 524, however it is expressly contemplated that other deposition methods are possible. Additionally, while it is illustrated in previous figures that filament 522 contacts the abrasive particles at tips, or along an edge, at a point in the center of each abrasive particle, it is expressly contemplated that filament 522 may contact at an asymmetrical position, which may aid in orienting lineal aligned abrasive particles. [0063] In step 540 the filament is cured, dried, or an adhesive is set such that the lineal aligned abrasive particle 532 is formed and ready to be used in an abrasive article.
  • filament 522 may be a material designed to sublime out or form part of the bond matrix. It is important to take into account the size of filament 522 in order to account for final porosity and / or bond matrix material.
  • FIG. 5B illustrates a different method of printing a filament onto a plurality of abrasive particles. While FIG.5A illustrated a method 500 for depositing a filament onto an edge of abrasive particles, FIG.5B illustrates a method 550 for depositing a filament onto a face of each abrasive particle.
  • a tool 562 is provided with cavities 564 that are sized to receive abrasive particles 566 such that a face of the abrasive particles 566 are parallel to the bottom surface of cavities 564.
  • all cavities 564 of tool 562 are filled with particles 566. However, it is expressly contemplated that, in some embodiments, not all cavities 564 will contain particles.
  • a filament 572 is deposited along the faces of abrasive particles 566 by an applicator 574. Filament 572 may be extruded, printed, or otherwise deposited. In some embodiments, filament is adhered to particles 566 using an adhesive.
  • a lineal aligned abrasive particle 582 is ready to be used in an abrasive article.
  • the abrasive particles 566 are separated by spacings 588, which may be the same or different between adjacent particles 566.
  • Each abrasive particle has a width 586, and filament has a length 584.
  • a filament length 548 may be up to 10 times longer than abrasive particle width 586, up to 50 times, up to 100 times or even longer.
  • FIGS.5A and 5B illustrate embodiments with a printed filament.
  • the filament can be comprised of any extrudable or printed material including a thermoplastic (such as polycarbonate, polyetherimide, polysulfone, polystyrene, polybutylene, acrylonitrile-butadiene-styrene block copolymer, polypropylene, acetal polymers, polyurethanes, polyamide, polyester, polyethylene or combinations thereof), a hot melt adhesive, glass etc.
  • a thermoplastic such as polycarbonate, polyetherimide, polysulfone, polystyrene, polybutylene, acrylonitrile-butadiene-styrene block copolymer, polypropylene, acetal polymers, polyurethanes, polyamide, polyester, polyethylene or combinations thereof
  • the filament may be another material that is adhered to the abrasive particles, including glass filaments, such as glass fiver provided by Vetrotex, Saint-Gobain; fiber filaments, ceramic filaments, such as 3M NextelTM; metal filaments such as BASF UltrafuseTM 316L metal 3D printing filament; etc.
  • glass filaments such as glass fiver provided by Vetrotex, Saint-Gobain
  • fiber filaments such as 3M NextelTM
  • metal filaments such as BASF UltrafuseTM 316L metal 3D printing filament
  • lineal aligned abrasive particle structure 100 can be formed by aligning particles 102 in a tool and inserting filament 104 into existing apertures.
  • FIG.6A illustrates a filament 10 with a number of abrasive particles 20 adhered thereto.
  • the abrasive filament 10 may be any suitable extruded or printed filament.
  • the abrasive particles 20 may be any suitable abrasive particles as described herein.
  • abrasive particles 20 are precisely shaped particles spaced apart along filament 10.
  • particles 20 are spaced roughly equally apart both along a length 22 of filament 10 and a perimeter of filament 10.
  • FIG.6B illustrates precisely positioned P36+ triangularly shaped abrasive grains in a spiral pattern about a filament.
  • FIG.6C illustrates precisely positioned P36+ triangularly shaped abrasive grains positioned about a circumference of a filament.
  • FIG.6D illustrates precisely positioned P60+ triangularly shaped abrasive grains in a spiral pattern about a filament.
  • the filament may be any suitable material selected to either survive abrasive article formation or be destroyed during abrasive article formation (e.g.
  • the filament may be Nylon (polyamide), Polyester (polyethylene terephthalate glycol PTEG), High Density Polyethylene (HDPE), Acrylonitrile Butadiene Styrene (ABS), Polypropylene, Poly Vinyl Acetate (PVA), Polylactic Acid (PLA), TPU (thermoplastic polyurethane), Carbon Fiber or another suitable material.
  • FIG.6E illustrates a schematic illustrating how lineal aligned abrasive particles may be formed. Tool 50 extends into the page, as illustrated by signifier. Filaments 52 are coated in an adhesive 54 and drawn through the indentations in tool 50.
  • Filaments 52 are rotated, as illustrated by arrow 60, for example either clockwise or counterclockwise, such that particles 56 can be dropped into position.
  • the distance between particles 56 along a perimeter of filaments 52 is dictated by a speed of rotation of filaments 52, as well as a speed at which particles 56 are dropped.
  • FIGS. 6A-6E illustrate abrasive particles coupled to a filament along a thickness, it is expressly contemplated that, as described herein, abrasive particles may also be coupled along a face, vertex or edge, in other embodiments.
  • FIG. 7 illustrates a method of making an abrasive article in accordance with embodiments herein.
  • the abrasive particles are formed, linked and then used to form an abrasive article.
  • precision shaped abrasive particles are formed.
  • the abrasive particles are formed from a ceramic material, in one embodiment.
  • the ceramic material may be an alumina- based material, or a zirconia-based material, or another suitable material. It is also expressly contemplated that the abrasive particle material may be a doped material, as described herein.
  • the abrasive particle material may be continuous composed of a single material or a blend of materials.
  • the abrasive particles may also contain discrete portions, which may be doped more heavily, formed of a different material, or have a different blend of material, for example. Additionally, the abrasive particles may contain one or more phases of different materials. [0077] While FIGS. 1-5 illustrate triangles, it is expressly contemplated that other polygonal shapes can serve as the basis for an abrasive particle. For example, another triangle shape, such as a scalene, isosceles, equilateral, right, acute or obtuse triangle may also serve as a polygonal shape for an abrasive particle. Additionally, a parallelogram, rectangle, square or other four-sided shape may also serve as a theoretical polygonal basis for an abrasive particle.
  • each face of an abrasive particle can be controlled, in part, by varying the length of either a height, a width, or a radius.
  • each edge can have any suitable length
  • each edge can generally have a length in a range of from about 0.01 mm to about 10 mm, about 0.03 mm to about 5 mm, less than, equal to, or greater than about 0.01 mm, 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or about 10 mm.
  • Abrasive particles can be formed from many suitable materials or combinations of materials.
  • shaped abrasive particle can comprise a ceramic material or a polymeric material.
  • Useful ceramic materials include, for example, fused aluminum oxide, heat treated aluminum oxide, white fused aluminum oxide, ceramic aluminum oxide materials such as those commercially available as 3M CERAMIC ABRASIVE GRAIN from 3M Company of St.
  • aluminosilicates e.g., mullite, cordierite
  • perovskite silicon carbide, silicon nitride, titanium carbide, titanium nitride, aluminum carbide, aluminum nitride, zirconium carbide, zirconium nitride, iron carbide, aluminum oxynitride, silicon aluminum oxynitride, aluminum titanate, tungsten carbide, tungsten nitride, steatite, diamond, cubic boron nitride, sol-gel derived ceramics (e.g., alumina ceramics doped with an additive), silica (e.g., quartz, glass beads, glass bubbles and glass fibers) and the like, or a combination thereof.
  • silica e.g., quartz, glass beads, glass bubbles and glass fibers
  • sol-gel derived crushed ceramic particles can be found in U.S. Pat. Nos.4,314,827 (Leitheiser et al.), 4,623,364 (Cottringer et al.); 4,744,802 (Schwabel), 4,770,671 (Monroe et al.); and 4,881,951 (Monroe et al.).
  • a modifying additive can function to enhance some desirable property of the abrasive or increase the effectiveness of the subsequent sintering step.
  • Modifying additives or precursors of modifying additives can be in the form of soluble salts, typically water soluble salts.
  • They typically consist of a metal-containing compound and can be a precursor of oxide of magnesium, zinc, iron, silicon, cobalt, nickel, zirconium, hafnium, chromium, calcium, strontium, yttrium, praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, titanium, and mixtures thereof.
  • concentrations of these additives that can be present in the abrasive dispersion can be varied based on skill in the art. Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Pat. Nos.
  • Shaped abrasive particles that include a polymeric material can be characterized as soft abrasive particles.
  • Soft shaped abrasive particles can include any suitable material or combination of materials.
  • the soft shaped abrasive particles can include a reaction product of a polymerizable mixture including one or more polymerizable resins.
  • the one or more polymerizable resins are chosen from a phenolic resin, a urea formaldehyde resin, a urethane resin, a melamine resin, an epoxy resin, a bismaleimide resin, a vinyl ether resin, an aminoplast resin (which may include pendant alpha, beta unsaturated carbonyl groups), an acrylate resin, an acrylated isocyanurate resin, an isocyanurate resin, an acrylated urethane resin, an acrylated epoxy resin, an alkyl resin, a polyester resin, a drying oil, or mixtures thereof.
  • the polymerizable mixture can include additional components such as a plasticizer, an acid catalyst, a cross-linker, a surfactant, a mild-abrasive, a pigment, a catalyst and an antibacterial agent.
  • additional components such as a plasticizer, an acid catalyst, a cross-linker, a surfactant, a mild-abrasive, a pigment, a catalyst and an antibacterial agent.
  • the polymerizable resin or resins may be in a range of from about 35 wt% to about 99.9 wt% of the polymerizable mixture, about 40 wt% to about 95 wt%, or less than, equal to, or greater than about 35 wt%, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, or about 99.9 wt%.
  • the cross-linker may be in a range of from about 2 wt% to about 60 wt% of the polymerizable mixture, from about 5 wt% to about 10 wt%, or less than, equal to, or greater than about 2 wt%, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt%.
  • suitable cross- linkers include a cross-linker available under the trade designation CYMEL 303 LF, of Allnex USA Inc., Alpharetta, Georgia, USA; or a cross-linker available under the trade designation CYMEL 385, of Allnex USA Inc., Alpharetta, Georgia, USA.
  • the mild-abrasive may be in a range of from about 5 wt% to about 65 wt% of the polymerizable mixture, about 10 wt% to about 20 wt%, or less than, equal to, or greater than about 5 wt%, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, or about 65 wt%.
  • suitable mild-abrasives include a mild-abrasive available under the trade designation MINSTRON 353 TALC, of Imerys Talc America, Inc., Three Forks, Montana, USA; a mild-abrasive available under the trade designation USG TERRA ALBA NO.1 CALCIUM SULFATE, of USG Corporation, Chicago, Illinois, USA; Recycled Glass (40-70 Grit) available from ESCA Industries, Ltd., Hatfield, Pennsylvania, USA, silica, calcite, nepheline, syenite, calcium carbonate, or mixtures thereof.
  • MINSTRON 353 TALC of Imerys Talc America, Inc., Three Forks, Montana, USA
  • USG TERRA ALBA NO.1 CALCIUM SULFATE of USG Corporation, Chicago, Illinois, USA
  • Recycled Glass (40-70 Grit) available from ESCA Industries, Ltd., Hatfield, Pennsylvania, USA, silica, calcite, nep
  • the plasticizer may be in a range of from about 5 wt% to about 40 wt% of the polymerizable mixture, about 10 wt% to about 15 wt%, or less than, equal to, or greater than about 5 wt%, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or about 40 wt%.
  • suitable plasticizers include acrylic resins or styrene butadiene resins.
  • acrylic resins include an acrylic resin available under the trade designation RHOPLEX GL-618, of DOW Chemical Company, Midland, Michigan, USA; an acrylic resin available under the trade designation HYCAR 2679, of the Lubrizol Corporation, Wickliffe, Ohio, USA; an acrylic resin available under the trade designation HYCAR 26796, of the Lubrizol Corporation, Wickliffe, Ohio, USA; a polyether polyol available under the trade designation ARCOL LG-650, of DOW Chemical Company, Midland, Michigan, USA; or an acrylic resin available under the trade designation HYCAR 26315, of the Lubrizol Corporation, Wickliffe, Ohio, USA.
  • the acid catalyst may be in a range of from 1 wt% to about 20 wt% of the polymerizable mixture, about 5 wt% to about 10 wt%, or less than, equal to, or greater than about 1 wt%, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 wt%.
  • suitable acid catalysts include a solution of aluminum chloride or a solution of ammonium chloride.
  • the surfactant can be in a range of from about 0.001 wt% to about 15 wt% of the polymerizable mixture about 5 wt% to about 10 wt%, less than, equal to, or greater than about 0.001 wt%, 0.01, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt%.
  • Suitable surfactants include a surfactant available under the trade designation GEMTEX SC-85-P, of Innospec Performance Chemicals, Salisbury, North Carolina, USA; a surfactant available under the trade designation DYNOL 604, of Air Products and Chemicals, Inc., Allentown, Pennsylvania, USA; or a surfactant available under the trade designation XIAMETER AFE 1520, of DOW Chemical Company, Midland, Michigan, USA.
  • an antimicrobial agent may be in a range of from 0.5 wt% to about 20 wt% of the polymerizable mixture, about 10 wt% to about 15 wt%, or less than, equal to, or greater than about 0.5 wt%, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or about 20 wt%.
  • An example of a suitable antimicrobial agent includes zinc pyrithione.
  • a pigment may be in a range of from about 0.1 wt% to about 10 wt% of the polymerizable mixture, about 3 wt% to about 5 wt%, less than, equal to, or greater than about 0.1 wt%, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or about 10 wt%.
  • Suitable pigments include a pigment dispersion available under the trade designation SUNSPERSE BLUE 15, of Sun Chemical Corporation, Parsippany, New Jersey, USA; a pigment dispersion available under the trade designation SUNSPERSE VIOLET 23, of Sun Chemical Corporation, Parsippany, New Jersey, USA; a pigment dispersion available under the trade designation SUN BLACK, of Sun Chemical Corporation, Parsippany, New Jersey, USA; or a pigment dispersion available under the trade designation BLUE PIGMENT B2G, of Clariant Ltd., Charlotte, North Carolina, USA.
  • SUNSPERSE BLUE 15 a pigment dispersion available under the trade designation SUNSPERSE VIOLET 23, of Sun Chemical Corporation, Parsippany, New Jersey, USA
  • SUN BLACK of Sun Chemical Corporation, Parsippany, New Jersey, USA
  • BLUE PIGMENT B2G of Clariant Ltd., Charlotte, North Carolina, USA.
  • a shaped abrasive particle is free of a binder and is not an agglomeration of abrasive particles held together by a binder or other adhesive material.
  • Shaped abrasive particle can be formed in many suitable manners for example, the shaped abrasive particle can be made according to a multi-operation process. The process can be carried out using any material or precursor dispersion material.
  • the process can include the operations of making either a seeded or non-seeded precursor dispersion that can be converted into a corresponding (e.g., a boehmite sol-gel that can be converted to alpha alumina); filling one or more mold cavities having the desired outer shape of shaped abrasive particle with a precursor dispersion; drying the precursor dispersion to form precursor shaped abrasive particle; removing the precursor shaped abrasive particle from the mold cavities; calcining the precursor shaped abrasive particle to form calcined, precursor shaped abrasive particle; and then sintering the calcined, precursor shaped abrasive particle to form shaped abrasive particle.
  • a seeded or non-seeded precursor dispersion that can be converted into a corresponding (e.g., a boehmite sol-gel that can be converted to alpha alumina)
  • the mold cavities may be filled with a melamine to form melamine shaped abrasive particles.
  • Shaped abrasive particles may also be formed using a non-hydrated alumina method, for example as described in WO 2014/070468, published on May 8, 2014, incorporated herein by reference.
  • the process can include the operation of providing either a seeded or non-seeded dispersion of a precursor that can be converted into ceramic. In examples where the precursor is seeded, the precursor can be seeded with an oxide of an iron (e.g., FeO).
  • the precursor dispersion can include a liquid that is a volatile component.
  • the volatile component is water.
  • the dispersion can include a sufficient amount of liquid for the viscosity of the dispersion to be sufficiently low to allow filling mold cavities and replicating the mold surfaces, but not so much liquid as to cause subsequent removal of the liquid from the mold cavity to be prohibitively expensive.
  • the precursor dispersion includes from 2 percent to 90 percent by weight of the particles that can be converted into ceramic, such as particles of aluminum oxide monohydrate (boehmite), and at least 10 percent by weight, or from 50 percent to 70 percent, or 50 percent to 60 percent, by weight, of the volatile component such as water.
  • the precursor dispersion in some embodiments contains from 30 percent to 50 percent, or 40 percent to 50 percent solids by weight.
  • suitable precursor dispersions include zirconium oxide sols, vanadium oxide sols, cerium oxide sols, aluminum oxide sols, and combinations thereof.
  • Suitable aluminum oxide dispersions include, for example, boehmite dispersions and other aluminum oxide hydrates dispersions. Boehmite can be prepared by known techniques or can be obtained commercially. Examples of commercially available boehmite include products having the trade designations “DISPERAL” and “DISPAL”, both available from Sasol North America, Inc., or “HIQ-40” available from BASF Corporation.
  • the physical properties of the resulting shaped abrasive particle can generally depend upon the type of material used in the precursor dispersion. As used herein, a “gel” is a three- dimensional network of solids dispersed in a liquid.
  • the precursor dispersion can contain a modifying additive or precursor of a modifying additive.
  • the modifying additive can function to enhance some desirable property of the abrasive particles or increase the effectiveness of the subsequent sintering step.
  • Modifying additives or precursors of modifying additives can be in the form of soluble salts, such as water-soluble salts.
  • They can include a metal-containing compound and can be a precursor of an oxide of magnesium, zinc, iron, silicon, cobalt, nickel, zirconium, hafnium, chromium, yttrium, praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, titanium, and mixtures thereof.
  • concentrations of these additives that can be present in the precursor dispersion can be varied.
  • the introduction of a modifying additive or precursor of a modifying additive can cause the precursor dispersion to gel.
  • the precursor dispersion can also be induced to gel by application of heat over a period of time to reduce the liquid content in the dispersion through evaporation.
  • the precursor dispersion can also contain a nucleating agent.
  • Nucleating agents suitable for this disclosure can include fine particles of alpha alumina, alpha ferric oxide or its precursor, titanium oxides and titanates, chrome oxides, or any other material that will nucleate the transformation. The amount of nucleating agent, if used, should be sufficient to effect the transformation of alpha alumina.
  • a peptizing agent can be added to the precursor dispersion to produce a more stable hydrosol or colloidal precursor dispersion.
  • Suitable peptizing agents are monoprotic acids or acid compounds such as acetic acid, hydrochloric acid, formic acid, and nitric acid. Multiprotic acids can also be used, but they can rapidly gel the precursor dispersion, making it difficult to handle or to introduce additional components.
  • Some commercial sources of boehmite contain an acid titer (such as absorbed formic or nitric acid) that will assist in forming a stable precursor dispersion.
  • the precursor dispersion can be formed by any suitable means; for example, in the case of a sol-gel alumina precursor, it can be formed by simply mixing aluminum oxide monohydrate with water containing a peptizing agent or by forming an aluminum oxide monohydrate slurry to which the peptizing agent is added.
  • Defoamers or other suitable chemicals can be added to reduce the tendency to form bubbles or entrain air while mixing. Additional chemicals such as wetting agents, alcohols, or coupling agents can be added if desired.
  • a further operation can include providing a mold having at least one mold cavity, or a plurality of cavities formed in at least one major surface of the mold.
  • the mold is formed as a production tool, which can be, for example, a belt, a sheet, a continuous web, a coating roll such as a rotogravure roll, a sleeve mounted on a coating roll, or a die.
  • the production tool can include polymeric material.
  • suitable polymeric materials include thermoplastics such as polyesters, polycarbonates, poly(ether sulfone), poly(methyl methacrylate), polyurethanes, polyvinylchloride, polyolefin, polystyrene, polypropylene, polyethylene or combinations thereof, or thermosetting materials.
  • the entire tooling is made from a polymeric or thermoplastic material.
  • the surfaces of the tooling in contact with the precursor dispersion while the precursor dispersion is drying include polymeric or thermoplastic materials, and other portions of the tooling can be made from other materials.
  • a suitable polymeric coating can be applied to a metal tooling to change its surface tension properties, for example.
  • a polymeric or thermoplastic production tool can be replicated off a metal master tool.
  • the master tool can have the inverse pattern of that desired for the production tool.
  • the master tool can be made in the same manner as the production tool.
  • the master tool is made out of metal (e.g., nickel) and is diamond-turned.
  • the master tool is at least partially formed using stereolithography.
  • the polymeric sheet material can be heated along with the master tool such that the polymeric material is embossed with the master tool pattern by pressing the two together.
  • a polymeric or thermoplastic material can also be extruded or cast onto the master tool and then pressed.
  • the thermoplastic material is cooled to solidify and produce the production tool. If a thermoplastic production tool is utilized, then care should be taken not to generate excessive heat that can distort the thermoplastic production tool, limiting its life.
  • Access to cavities can be from an opening in the top surface or bottom surface of the mold. In some examples, the cavities can extend for the entire thickness of the mold. Alternatively, the cavities can extend only for a portion of the thickness of the mold.
  • the top surface is substantially parallel to the bottom surface of the mold with the cavities having a substantially uniform depth.
  • At least one side of the mold, the side in which the cavities are formed, can remain exposed to the surrounding atmosphere during the step in which the volatile component is removed.
  • the cavities have a specified three-dimensional shape to make shaped abrasive particle.
  • the depth dimension is equal to the perpendicular distance from the top surface to the lowermost point on the bottom surface.
  • the depth of a given cavity can be uniform or can vary along its length and/or width.
  • the cavities of a given mold can be of the same shape or of different shapes.
  • a further operation involves filling the cavities in the mold with the precursor dispersion (e.g., by a conventional technique).
  • a knife roll coater or vacuum slot die coater can be used.
  • a mold release agent can be used to aid in removing the particles from the mold if desired.
  • mold release agents include oils such as peanut oil or mineral oil, fish oil, silicones, polytetrafluoroethylene, zinc stearate, and graphite.
  • a mold release agent such as peanut oil, in a liquid, such as water or alcohol, is applied to the surfaces of the production tooling in contact with the precursor dispersion such that from about 0.1 mg/in 2 (0.6 mg/cm 2 ) to about 3.0 mg/in 2 (20 mg/cm 2 ), or from about 0.1 mg/in 2 (0.6 mg/cm 2 ) to about 5.0 mg/in 2 (30 mg/cm 2 ), of the mold release agent is present per unit area of the mold when a mold release is desired.
  • the top surface of the mold is coated with the precursor dispersion. The precursor dispersion can be pumped onto the top surface.
  • a scraper or leveler bar can be used to force the precursor dispersion fully into the cavity of the mold.
  • the remaining portion of the precursor dispersion that does not enter the cavity can be removed from the top surface of the mold and recycled.
  • a small portion of the precursor dispersion can remain on the top surface, and in other examples the top surface is substantially free of the dispersion.
  • the pressure applied by the scraper or leveler bar can be less than 100 psi (0.6 MPa), or less than 50 psi (0.3 MPa), or even less than 10 psi (60 kPa). In some examples, no exposed surface of the precursor dispersion extends substantially beyond the top surface.
  • a further operation involves removing the volatile component to dry the dispersion.
  • the volatile component can be removed by fast evaporation rates. In some examples, removal of the volatile component by evaporation occurs at temperatures above the boiling point of the volatile component. An upper limit to the drying temperature often depends on the material the mold is made from. For polypropylene tooling, the temperature should be less than the melting point of the plastic.
  • the drying temperatures can be from about 90° C to about 165° C, or from about 105° C to about 150° C, or from about 105° C to about 120° C. Higher temperatures can lead to improved production speeds but can also lead to degradation of the polypropylene tooling, limiting its useful life as a mold.
  • the precursor dispersion shrinks, often causing retraction from the cavity walls. For example, if the cavities have planar walls, then the resulting shaped abrasive particle can tend to have at least three concave major sides.
  • a further operation involves removing resultant precursor shaped abrasive particle from the mold cavities.
  • the precursor shaped abrasive particle can be removed from the cavities by using the following processes alone or in combination on the mold: gravity, vibration, ultrasonic vibration, vacuum, or pressurized air to remove the particles from the mold cavities.
  • the precursor shaped abrasive particle can be further dried outside of the mold.
  • a further operation involves calcining the precursor shaped abrasive particle. During calcining, essentially all the volatile material is removed, and the various components that were present in the precursor dispersion are transformed into metal oxides.
  • the precursor shaped abrasive particle are generally heated to a temperature from 400° C to 800° C and maintained within this temperature range until the free water and over 90 percent by weight of any bound volatile material are removed.
  • a water-soluble salt can be introduced by impregnation into the pores of the calcined, precursor shaped abrasive particle. Then the precursor shaped abrasive particle are pre- fired again.
  • a further operation can involve sintering the calcined, precursor shaped abrasive particle to form the abrasive particles. In some examples where the precursor includes rare earth metals, however, sintering may not be necessary.
  • the calcined, precursor shaped abrasive particle Prior to sintering, the calcined, precursor shaped abrasive particle are not completely densified and thus lack the desired hardness to be used as shaped abrasive particle. Sintering takes place by heating the calcined, precursor shaped abrasive particle to a temperature of from 1000° C to 1650° C. The length of time for which the calcined, precursor shaped abrasive particle can be exposed to the sintering temperature to achieve this level of conversion depends upon various factors, but from five seconds to 48 hours is possible. [00114] In another embodiment, the duration of the sintering step ranges from one minute to 90 minutes.
  • the shaped abrasive particle 14 can have a Vickers hardness of 10 GPa (gigaPascals), 16 GPa, 18 GPa, 20 GPa, or greater.
  • Additional operations can be used to modify the described process, such as, for example, rapidly heating the material from the calcining temperature to the sintering temperature, and centrifuging the precursor dispersion to remove sludge and/or waste. Moreover, the process can be modified by combining two or more of the process steps if desired.
  • the polymerizable mixtures described herein can be deposited in a cavity.
  • the cavity can have a shape corresponding to the negative impression of the desired shaped abrasive particle.
  • the polymerizable mixture is cured therein. Curing can occur at room temperature (e.g., about 25 °C) or at any temperature above room temperature. Curing can also be accomplished by exposing the polymerizable mixture to a source of electromagnetic radiation or ultraviolet radiation.
  • Shaped abrasive particles can be independently sized according to an abrasives industry recognized specified nominal grade. Abrasive industry recognized grading standards include those promulgated by ANSI (American National Standards Institute), FEPA (Federation of European Producers of Abrasives), and JIS (Japanese Industrial Standard).
  • ANSI grade designations include, for example: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 36, ANSI 46, ANSI 54, ANSI 60, ANSI 70, ANSI 80, ANSI 90, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400, and ANSI 600.
  • FEPA grade designations include F4, F5, F6, F7, F8, F10, F12, F14, F16, F18, F20, F22, F24, F30, F36, F40, F46, F54, F60, F70, F80, F90, F100, F120, F150, F180, F220, F230, F240, F280, F320, F360, F400, F500, F600, F800, F1000, F1200, F1500, and F2000.
  • JIS grade designations include JIS8, JIS12, JIS16, JIS24, JIS36, JIS46, JIS54, JIS60, JIS80, JIS100, JIS150, JIS180, JIS220, JIS240, JIS280, JIS320, JIS360, JIS400, JIS600, JIS800, JIS1000, JIS1500, JIS2500, JIS4000, JIS6000, JIS8000, and JIS10,000.
  • Any one of the surfaces of a shaped abrasive particle can include a surface feature such as a substantially planar surface; a substantially planar surface having a triangular, rectangular, hexagonal, or other polygonal perimeter; a concave surface; a convex surface; an aperture; a ridge; a line or a plurality of lines; a protrusion; a point; or a depression.
  • the surface feature can be chosen to change the cut rate, reduce wear of the formed abrasive particles, or change the resulting finish of an abrasive article.
  • a shaped abrasive particle 300 can have a combination of the above shape elements (e.g., convex sides, concave sides, irregular sides, and planar sides).
  • the shaped abrasive particles can have at least one sidewall, which may be a sloping sidewall. In some embodiments, more than one (for example two or three) sloping sidewall can be present and the slope or angle for each sloping sidewall may be the same or different. In other embodiments, the sidewall can be minimized for particles where the first and the second faces taper to a thin edge or point where they meet instead of having a sidewall.
  • the sloping sidewall can also be defined by a radius, R (as illustrated in Fig 5B of US Patent Application No.2010/0151196).
  • the radius, R can be varied for each of the sidewalls.
  • Specific examples of shaped particles having a ridge line include roof-shaped particles, for example particles as illustrated, in Fig.4A to 4C of WO 2011/068714.
  • roof- shaped particles include particles having the shape of a hip roof, or hipped roof (a type of roof wherein any sidewalls facets present slope downwards from the ridge line to the first side.
  • a hipped roof typically does not comprise vertical sidewall(s) or facet(s)).
  • Shaped abrasive particles can have one or more shape features selected from: an opening (preferably one extending or passing through the first and second side); at least one recessed (or concave) face or facet; at least one face or facet which is shaped outwardly (or convex); at least one side comprising a plurality of grooves; at least one fractured surface; a cavity, a low roundness factor; or a combination of one or more of said shape features.
  • Shaped abrasive particles 300 can also comprise a plurality of ridges on their surfaces.
  • the plurality of grooves can be formed by a plurality of ridges (or grooves) in the bottom surface of a mold cavity that have been found to make it easier to remove the precursor shaped abrasive particles from the mold.
  • the plurality of grooves (or ridges) is not particularly limited and can, for example, comprise parallel lines which may or may not extend completely across the side. Preferably, the parallel lines intersect with the perimeter along a first edge at a 90° angle.
  • the cross-sectional geometry of a groove or ridge can be a truncated triangle, triangle, or other geometry as further discussed in the following.
  • the depth, of the plurality of grooves can be between about 1 micrometer to about 400 micrometers.
  • the plurality of grooves comprises a cross hatch pattern of intersecting parallel lines which may or may not extend completely across the face.
  • the cross hatch pattern can use intersecting parallel or non-parallel lines, various percent spacing between the lines, arcuate intersecting lines, or various cross-sectional geometries of the grooves.
  • the number of ridges (or grooves) in the bottom surface of each mold cavity can be between 1 and about 100, or between 2 to about 50, or between about 4 to about 25 and thus form a corresponding number of grooves (or ridges) in the shaped abrasive particles.
  • Methods for making shaped abrasive particles having at least one sloping sidewall are for example described in US Patent Application Publication No. 2009/0165394.
  • Methods for making shaped abrasive particles having an opening are for example described in US Patent Application Publication No.2010/0151201 and 2009/0165394.
  • Methods for making shaped abrasive particles having grooves on at least one side are for example described in US Patent Application Publication No.2010/0146867.
  • Methods for making dish-shaped abrasive particles are for example described in US Patent Application Publication Nos.2010/0151195 and 2009/0165394.
  • Methods for making shaped abrasive particles with low Roundness Factor are for example described in US Patent Application Publication No.2010/0319269.
  • Methods for making shaped abrasive particles with at least one fractured surface are for example described in US Patent Application Publication Nos. 2009/0169816 and 2009/0165394.
  • Methods for making abrasive particles wherein the second side comprises a vertex (for example, dual tapered abrasive particles) or a ridge line (for example, roof shaped particles) are for example described in WO 2011/068714.
  • at least one magnetic material may be included within or coated to shaped abrasive particle.
  • magnétique materials examples include iron; cobalt; nickel; various alloys of nickel and iron marketed as Permalloy in various grades; various alloys of iron, nickel and cobalt marketed as Fernico, Kovar, FerNiCo I, or FerNiCo II; various alloys of iron, aluminum, nickel, cobalt, and sometimes also copper and/or titanium marketed as Alnico in various grades; alloys of iron, silicon, and aluminum (about 85:9:6 by weight) marketed as Sendust alloy; Heusler alloys (e.g., Cu 2 MnSn); manganese bismuthide (also known as Bismanol); rare earth magnetizable materials such as gadolinium, dysprosium, holmium, europium oxide, alloys of neodymium, iron and boron (e.g., Nd 2 Fe 14 B), and alloys of samarium and cobalt (e.g., SmCo 5 ); MnSb; MnOFe 2 O 3
  • the magnetizable material is an alloy containing 8 to 12 weight percent aluminum, 15 to 26 wt% nickel, 5 to 24 wt% cobalt, up to 6 wt% copper, up to 1 % titanium, wherein the balance of material to add up to 100 wt% is iron.
  • a magnetizable coating can be deposited on an abrasive particle 100 using a vapor deposition technique such as, for example, physical vapor deposition (PVD) including magnetron sputtering.
  • PVD physical vapor deposition
  • Including these magnetizable materials can allow shaped abrasive particle to be responsive a magnetic field. Any of shaped abrasive particles can include the same material or include different materials.
  • the magnetic coating may be a continuous coating, for example that coats an entire abrasive particle, or at least coats an entire surface of an abrasive particle.
  • a continuous coating refers to a coating present with no uncoated portions on the coated surface.
  • the coating is a unitary coating – formed of a single layer of magnetic material and not as discrete magnetic particulates.
  • the magnetic coating is provided on an abrasive particle while the particle is still in a mold cavity, such that the magnetic coating directly contacts an abrasive particle precursor surface.
  • the thickness of the magnetic coating is at most equal to, or preferably less than, a thickness of the abrasive particle.
  • the magnetic coating is not more than about 20 wt.% of the final particle, or not more than about 10 wt.% of the final particle, or not more than 5 wt.% of the final particle.
  • a filament is coupled to the abrasive particles prior to the sintering, calcining or drying step, such that the filament is placed prior to the complete processing of the abrasive particles.
  • the filament is added post-firing.
  • the filament may be composed of a material that cannot survive the temperatures required to sinter the abrasive particles.
  • the aligning step 620 may not be necessary as the PSG may already be aligned during formation.
  • the shaped abrasive particles are aligned. As described with respect to FIGS.5A and 5B, in one embodiment, the abrasive particles are aligned using a tool with cavities 622. The abrasive particles may be dropped, blown, or otherwise provided to the tool cavities. In another embodiment the abrasive particles are aligned using electrostatic force 624. In a further embodiment, the abrasive particles are aligned using a magnetic force 626. However other alignment procedures 628 are expressly contemplated.
  • a filament is added that connects the aligned abrasive particles.
  • the abrasive particles may be aligned in any suitable fashion for coupling to a filament. While FIGS. 5A and 5B illustrate a colinear alignment, it is expressly contemplated that other arrangements are possible. For example, a curve may be preferred in embodiments where the filament cures into a rigid structure and is to be used in a bonded abrasive article.
  • the filament may be composed of any number of materials, depending on the abrasive article it will be incorporated into.
  • the filament is flexible in some embodiments the filament is rigid, in some embodiments the filament is compliant, in some embodiments the filament expands or contracts under heat.
  • the filament may have any suitable melting or sublimation point, depending on the specifications of the final abrasive article.
  • the filament may be placed using any suitable mechanism such as printing 632, extrusion 634, using an adhesive 636, or another method 638.
  • abrasive particles Illustrated herein are embodiments where abrasive particles are parallel to each other, but it is expressly contemplated that abrasive particles may be coupled to the filament at an angle other than perpendicular to the fiber as well. Additionally, the angle of the abrasive particles may be changed during processing, for example if the filament requires curing or cooling the abrasive particle position can be changed, for example pushed in one direction or another, or pulled using surface tension.
  • the orientation possibilities are many – particles could alternate perpendicularly or at a different angle, for example.
  • the abrasive particles are extruded with the filament, such that steps 620 and 630 occur simultaneously. It may then be possible to at least partially melt the filament, causing abrasive particles to protrude through.
  • an abrasive article is formed using the lineal aligned abrasive particle structures.
  • the lineal aligned abrasive particle structures may be aligned using any suitable method including machine placement, pattern coating, electrostatic alignment, or magnetic alignment.
  • the abrasive article may be a coated abrasive article 642, illustrated in FIG. 7, a nonwoven abrasive article 644, illustrated in the Examples, a bonded abrasive article 646 as described in FIGS.4A and 4B, or another suitable abrasive article 648.
  • Magnetically aligning or orienting the lineal aligned abrasive particles requires the particles to be magnetizable.
  • the magnetizable lineal aligned abrasive particles are deposited onto an abrasive backing while being subjected to a magnetic field.
  • the magnetic field can be supplied by any external magnet (e.g., a permanent magnet or an electromagnet) or set of magnets.
  • the magnetic field typically ranges from 0.1 to 1 Tesla.
  • the magnetic field is substantially uniform on the scale of individual magnetizable lineal aligned abrasive particle structures. Magnetically aligning the lineal aligned abrasive particles with respect to each other generally requires two steps. First, providing the magnetizable abrasive particles described herein on a substrate having a major surface. Second, applying a magnetic field to the magnetizable lineal aligned abrasive particles such that a majority of the magnetizable lineal aligned abrasive particles are oriented substantially perpendicular to the major surface.
  • the magnetic field can be supplied by any external magnet (e.g., a permanent magnet or an electromagnet) or set of magnets. In some embodiments, the magnetic field typically ranges from 0.5 to 1.5 kOe. Preferably, the magnetic field is substantially uniform on the scale of individual magnetizable lineal aligned abrasive particle structures.
  • Magnetically responsive particles may include a magnetic coating applied before particle firing, as described in U.S. Provisional Nos. 62/914,778 filed on October 14, 2019 and 62/875,700 filed July 18, 2019, and 62/924,956, filed October 23, 2019, or after firing, as described in PCT Pat.
  • magnetically responsive element 670 may be part of material 650, or may be another treatment of abrasive particle 600 such that abrasive particle 600 is responsive to an applied magnetic field.
  • no magnetic coating is necessary as particles with some shapes herein may self-align, or may be aligned electrostatically.
  • a magnetic field can optionally be used to place and/or orient the lineal aligned abrasive particle structures prior to curing a binder (e.g., vitreous or organic) precursor to produce the abrasive article.
  • a binder e.g., vitreous or organic
  • the magnetic field may be substantially uniform over the magnetizable abrasive particles before they are fixed in position in the binder or continuous over the entire, or it may be uneven, or even effectively separated into discrete sections.
  • the orientation of the magnetic field is configured to achieve alignment of the magnetizable abrasive particles according to a predetermined orientation.
  • a coated abrasive article 642 the particles are adhered to a backing.
  • Any abrasive article such as abrasive belt or abrasive disc can include a make coat to adhere shaped abrasive particles, or a blend of shaped abrasive particles and crushed abrasive particles, to backing.
  • the backing is a nonwoven material.
  • the particles are adhered within a resin structure.
  • FIG.7 illustrates a coated abrasive article in accordance with embodiments herein.
  • the coated abrasive article 700 includes a backing 750 defining a substantially planar major surface along an x-y direction.
  • Backing 750 has a first layer of binder 740, which may be referred to as a make coat 740, applied over a first surface of the backing 750.
  • Attached or partially embedded in the make coat 740 are a plurality of lineally aligned abrasive particles 702, viewed end- on.
  • a second layer of binder 730 hereinafter referred to as a size coat 730, is dispersed over the shaped abrasive particles.
  • the coated abrasive article 700 can be formed to be any suitable abrasive article.
  • Backing 750 can be flexible or rigid. Examples of suitable materials for forming a flexible backing include a polymeric film, a metal foil, a woven fabric, a knitted fabric, paper, vulcanized fiber, a staple fiber, a continuous fiber, a nonwoven, a foam, a screen, a laminate, and combinations thereof. Backing 750 can be shaped to allow coated abrasive article 300 to be in the form of sheets, discs, belts, pads, or rolls.
  • backing 350 can be sufficiently flexible to allow coated abrasive article 700 to be formed into a loop to make an abrasive belt that can be run on suitable grinding equipment.
  • Make coat 740 secures the lineal aligned abrasive particle structures to backing 750, and a size coat 730 can help to reinforce particles within size make coat 740.
  • Make coat 740 and/or the size coat 730 can include a resinous adhesive.
  • the resinous adhesive can include one or more resins chosen from a phenolic resin, an epoxy resin, a urea-formaldehyde resin, an acrylate resin, an aminoplast resin, a melamine resin, an acrylated epoxy resin, a urethane resin, and mixtures thereof.
  • lineal aligned abrasive particle structures 702 may be beneficial because the filament is likely to help retain particles within the make coat. Additionally, in some embodiments, the filament is formed of a material more likely to bond with make resin 740.
  • the coated abrasive article 700 can be formed by applying make coat 740 on backing 750. Make coat 740 can be applied by any suitable technique such as roll coating. Lineal aligned abrasive particle structures 702 can then be deposited on make coat 740.
  • coated abrasive article 300 includes other shaped abrasive particles, crushed abrasive particles, and secondary shaped abrasive particles, those particles can be applied as discrete groups sorted by particle type, or together.
  • Lineal aligned abrasive particle structures 702 are deposited on backing 750, make coat 740 is cured at an elevated temperature or at room temperature for a set amount of time and lineal aligned abrasive particle structures 702 adhere to backing 750.
  • a size coat 730 can then be optionally applied over the coated abrasive article 700.
  • Abrasive particles 302 can be deposited on backing 350 through any suitable technique.
  • abrasive particles 302 can be deposited through a drop-coating technique or an electrostatic-coating technique onto backing 750.
  • lineal aligned abrasive particle structures 702 are free-form deposited on make coat 740.
  • an electrostatic -coating technique an electrostatically charged vibratory feeder can be used to propel lineal aligned abrasive particle structures 702 off of a feeding surface towards a conductive member located behind backing 750.
  • the feeding surface can be substantially horizontal and the coated backing can be traveling substantially vertically.
  • Lineal aligned abrasive particle structures 702 pick up a charge from the feeder and are drawn towards the backing by the conductive member.
  • Lineal aligned abrasive particle structures 702 can account for 100 wt% of the abrasive particles in any abrasive article. Alternatively, lineal aligned abrasive particle structures 702 can be part of a blend of abrasive particles distributed on backing 750.
  • shaped abrasive particles may be in a range of from about 5 wt% to about 95 wt% of the blend, about 10 wt% to about 80 wt%, about 30 wt% to about 50 wt%, or less than, equal to, or greater than about, 5 wt%, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or about 95 wt%, of the blend.
  • the balance of the abrasive particles may include conventional crushed abrasive particles. Crushed abrasive particles are generally formed through a mechanical crushing operation and have no replicated shape.
  • the balance of the abrasive particles can also include other shaped abrasive particles, that may for example, include an equilateral triangular shape (e.g., a flat triangular shaped abrasive particle or a tetrahedral shaped abrasive particle in which each major face of the tetrahedron is an equilateral triangle).
  • the make coat, size coat, or both can include any suitable resin such as a phenolic resin, an epoxy resin, a urea-formaldehyde resin, an acrylate resin, an aminoplast resin, a melamine resin, an acrylated epoxy resin, a urethane resin, or mixtures thereof.
  • the make coat, size coat, or both can include a filler, a grinding aid, a wetting agent, a surfactant, a dye, a pigment, a coupling agent, an adhesion promoter, or a mixture thereof.
  • fillers may include calcium carbonate, silica, talc, clay, calcium metasilicate, dolomite, aluminum sulfate, or a mixture thereof.
  • a distribution tool may also be used to apply lineal aligned abrasive particle structures 702 to backing 350.
  • the distribution tool including lineal aligned abrasive particle structures 702 may be the same tool illustrated in FIGS.5A and 5B used to form the lineal aligned abrasive particle structures 702 and may be left in contact with the backing for any suitable amount of time as lineal aligned abrasive particle structures 702 adhere to the make coat. After sufficient time has passed for good adhesion between shaped abrasive particles and the make coat, the production tool is removed and a size coat is optionally disposed over the shaped abrasive particles. [00149] Alignment of abrasive particles may be accomplished using electrostatic coating or magnetic coating, as described in PCT Pat. Appl. Publ. Nos.
  • WO2018/080703 (Nelson et al.), WO2018/080756 (Eckel et al.), WO2018/080704 (Eckel et al.), WO2018/080705 (Adefris et al.), WO2018/080765 (Nelson et al.), WO2018/080784 (Eckel et al.), WO2018/136271 (Eckel et al.), WO2018/134732 (Nienaber et al.), WO2018/080755 (Martinez et al.), WO2018/080799 (Nienaber et al.), WO2018/136269 (Nienaber et al.), WO2018/136268 (Jesme et al.), WO2019/207415 (Nienaber et al.), WO2019/207417 (Eckel et al.), WO2019/207416 (Nienaber e
  • Magnetic coatings may be applied before a firing process or after a firing process.
  • the magnetic coating may cause the lineal aligned abrasive particle structures to align in a magnetic field.
  • the shaped abrasive particles may align such that one of the vertices are pointing away from the backing.
  • additional magnetizable and/or non-magnetizable particles can be applied to the make layer precursor prior to curing.
  • the curable binder precursor includes a make layer precursor
  • the magnetizable particles include magnetizable abrasive particles.
  • a size layer precursor may be applied over the at least partially cured make layer precursor and the magnetizable abrasive particles, although this is not a requirement. If present, the size layer precursor is then at least partially cured at a second curing station, optionally with further curing of the at least partially cured make layer precursor.
  • FIG. 8 illustrates a method of using an abrasive article in accordance with an embodiment of the present invention.
  • Method 810 can be used to abrade a number of different workpieces. Upon contact, one of the abrasive article and the workpiece is moved relative to one another in a direction of use and a portion of the workpiece is removed.
  • workpiece materials include metal, metal alloys, steel, steel alloys, aluminum exotic metal alloys, ceramics, glass, wood, wood-like materials, composites, painted surfaces, plastics, reinforced plastics, stone, and/or combinations thereof.
  • the workpiece may be flat or have a shape or contour associated with it.
  • Exemplary workpieces include metal components, plastic components, particleboard, camshafts, crankshafts, furniture, and turbine blades.
  • Abrasive articles according to the present disclosure are useful for abrading a workpiece. Methods of abrading range from snagging (i.e., high pressure high stock removal) to polishing (e.g., polishing medical implants with coated abrasive belts), wherein the latter is typically done with finer grades of abrasive particles.
  • One such method includes the step of frictionally contacting an abrasive article (e.g., a coated abrasive article, a nonwoven abrasive article, or a bonded abrasive article) with a surface of the workpiece, and moving at least one of the abrasive article or the workpiece relative to the other to abrade at least a portion of the surface.
  • an abrasive article is provided.
  • the abrasive article includes a plurality of lineal aligned abrasive particle structures that are designed with a first direction of use and a second direction of use.
  • moving an abrasive article in a first direction of use 254 refers to moving an abrasive article such that an edge with a steeper slope encounters a workpiece first.
  • a second direction of use 252 refers to moving an abrasive article in an opposite direction.
  • a method of using an abrasive article such as abrasive belt or abrasive disc includes contacting shaped abrasive particles with a workpiece or substrate.
  • a cutting depth into the substrate or workpiece can be at least 1 ⁇ m about 10 ⁇ m, at least about 20 ⁇ m, at least about 30 ⁇ m, at least about 40 ⁇ m, at least about 50 ⁇ m, or at least about 60 ⁇ m.
  • the cutting depth may depend, in part, on the size of the abrasive particles. For example, smaller particles may have an even smaller cutting depth, such as less than 1 ⁇ m, or less than 0.5 ⁇ m, or less than 0.1 ⁇ m.
  • a portion of the substrate or workpiece is removed by the abrasive article as a swarf.
  • the abrasive articles described herein can have several advantages when moved in a preferred direction of use. For example, at the same applied force, cutting speed, or a combination thereof, an amount of material removed from the workpiece, length of a swarf removed from the workpiece, depth of cut in the workpiece, surface roughness of the workpiece or a combination thereof is greater in the first direction than in any other second direction.
  • At least about 10% more material is removed from the substrate or workpiece in the first direction of use, or at least about 15%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 100%, at least about 120%, at least about 130%, at least about 140%, at least about 150%.
  • about 15% to about 500% more material is removed in the first direction of use, or about 30% to about 70%, or about 40% to about 60%, or less than, equal to, or greater than about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, 150%, 155%, 160%, 165%, 170%, 175%, 180%, 185%, 190%, 195%, 200%, 205%, 210%, 215%, 220%, 225%, 230%, 235%, 240%, 245%, 250%, 255%, 260%, 265%, 270%, 275%, 280%, 285%, 290%, 295%, 300%, 305%, 310%, 315%, 320%, 325%, 330%, 335%, 340%, 345%, 350%, 355%, 360%, 365%, 370%, 375%, 40%,
  • a depth of cut into the substrate or workpiece may be at least about 10% deeper in the first direction of use, or at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 100%, at least about 120%, at least about 130%, at least about 140%, at least about 150%.
  • about 10% to about 500% deeper in the first direction of use or about 30% to about 70%, or about 40% to about 60%, or less than, equal to, or greater than about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, 140%, 145%, 150%, 155%, 160%, 165%, 170%, 175%, 180%, 185%, 190%, 195%, 200%, 205%, 210%, 215%, 220%, 225%, 230%, 235%, 240%, 245%, 250%, 255%, 260%, 265%, 270%, 275%, 280%, 285%, 290%, 295%, 300%, 305%, 310%, 315%, 320%, 325%, 330%, 335%, 340%, 345%, 350%, 355%, 360%, 365%, 370%, 375%, 380%
  • an arithmetical mean roughness value (Sa) of the workpiece or substrate cut by moving the abrasive article in first direction of use 254 can be higher than a corresponding substrate or workpiece cut under the exact same conditions but in the second direction of movement.
  • the surface roughness can be about 30% greater when the workpiece or substrate is cut in the first direction or about 40% greater, about 50% greater, about 60% greater, about 70% greater, about 80% greater, about 90% greater, about 100% greater, about 110% greater, about 120% greater, about 130% greater, about 140% greater, about 150% greater, about 160% greater, about 170% greater, about 180% greater, about 190% greater, about 200% greater, about 210% greater, about 220% greater, about 230% greater, about 240% greater, about 250% greater, about 260% greater, about 270% greater, about 280% greater, about 290% greater, about 300% greater, about 310% greater, about 320% greater, about 330% greater, about 340% greater, about 350% greater, about 360% greater, about 370% greater, about 380% greater, about 390% greater, about 400% greater, about 410% greater, about 420% greater, about 430% greater, about 440% greater, about 450% greater, about 460% greater, about 470% greater, about 480% greater, about 490% greater, or about 500% greater.
  • the arithmetical mean roughness value can be in a range of from about 1000 to about 2000, about 1000 to about 1100, or less than, equal to, or greater than about 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, or about 2000.
  • the abrasive article it is possible for the abrasive article to be moved in a second direction that is different than the first direction of use.
  • the second direction can be in a direction rotated about 1 degree to 360 degrees relative to the first direction of use, about 160 degrees to about 200 degrees, less than, equal to, or greater than about 1 degree, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 230, 240, 250, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 315, 320, 325, 330, 335, 340, 350, 355, or about 360 degrees.
  • lineal aligned abrasive particle structures described herein can be included in a random orbital sander or vibratory sander.
  • a lineal aligned abrasive particle structure includes a plurality of shaped abrasive particles.
  • Each of the shaped abrasive particles has a perimeter and a thickness.
  • the perimeter of each of the shaped abrasive particles is substantially similar.
  • the thickness of each of the shaped abrasive particles is substantially similar.
  • the lineal aligned abrasive particle structure also includes a filament coupled to each of the plurality of shaped abrasive particles.
  • the plurality of shaped abrasive particles are regularly spaced along the filament.
  • the structure may be implemented such that the shape includes a corner, a straight edge, a curved edge, a convex feature or a concave feature.
  • the structure may be implemented such that regularly spaced includes substantially similar spacing between adjacent particles. [00167] The structure may be implemented such that regularly spaced includes a pattern of spacing between a set of particles. [00168] The structure may be implemented such that the filament is coupled to a face of each of the plurality of abrasive particles. [00169] The structure may be implemented such that the filament is coupled to an edge of each of the plurality of abrasive particles. [00170] The structure may be implemented such that the filament is coupled to a vertex of each of the plurality of shaped abrasive particles. [00171] The structure may be implemented such that adjacent abrasive particles are coupled to the filament such that the adjacent abrasive particles have the same orientation.
  • the structure may be implemented such that adjacent abrasive particles are coupled to the filament such that the adjacent abrasive particles have different orientations.
  • the structure may be implemented such that the shaped abrasive particle includes a continuous composition throughout a portion of the shaped abrasive particle.
  • the structure may be implemented such that the portion is a whole of the shaped abrasive particle.
  • the structure may be implemented such that the filament includes a flexible material.
  • the structure may be implemented such that the filament is a cured material.
  • the structure may be implemented such that the filament is a compliant material.
  • the structure may be implemented such that the filament is a rigid material.
  • the structure may be implemented such that the filament includes a metal, a polymer, a ceramic or a fibrous material.
  • the structure may be implemented such that the filament includes a material that melts, volatizes, sublimes or decomposes during a curing step.
  • the structure may be implemented such that the filament is directly coupled to each of the plurality of abrasive particles.
  • the structure may be implemented such that the filament is adhered to each of the plurality of abrasive particles by an adhesive material.
  • the structure may be implemented such that the perimeter includes an equilateral shape, an equiangular shape, a star shape, a lens-shape, a lune-shape, a circular sector or a circular segment, an arcuate shape.
  • the structure may be implemented such that the perimeter includes a triangle, a parallelogram, a rectangle, a square, a star, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, a cross, a dog-bone, or a rod.
  • a method of making lineal aligned abrasive particle structures includes providing a plurality of shaped abrasive particles. Each of the plurality of shaped abrasive particles include a perimeter and a thickness. The method also includes orienting the plurality of shaped abrasive particles. The method also includes coupling a filament to each of the plurality of shaped abrasive particles. The plurality of shaped abrasive particles, when coupled to the filament, are oriented and regularly spaced. [00186] The method may also include curing the filament. [00187] The method may be implemented such that the filament is coupled to the particles with an adhesive or binder.
  • the method may be implemented such that providing the plurality of shaped abrasive particles includes providing a shaped abrasive particle precursor material. The method further includes drying the plurality of shaped abrasive particles. [00189] The method may be implemented such that the plurality of shaped abrasive particles are sintered abrasive particles. [00190] The method may be implemented such that orienting the plurality of shaped abrasive particles includes: providing a tool with a plurality of cavities. Each of the plurality of cavities is sized to receive one of the plurality of shaped abrasive particles. A shape of each of the plurality of cavities indicates the orientation of the corresponding particle.
  • the method may be implemented such that includes providing the plurality of shaped abrasive particles to the plurality of cavities.
  • the method may be implemented such that a spacing between adjacent shaped abrasive particles is similar to a spacing between adjacent cavities.
  • the method may be implemented such that an orientation of adjacent shaped abrasive particles is the same.
  • the method may be implemented such that an orientation of adjacent shaped abrasive particles is different.
  • the method may be implemented such that the filament has a preset shape.
  • the method may be implemented such that the filament is a curved filament.
  • the method may be implemented such that the filament includes a first portion and a second portion.
  • the first and second portions are coupled at a vertex.
  • the first and second portions form an angle at the vertex.
  • the angle is an acute angle, a right angle or an obtuse angle.
  • the method may be implemented such that orienting the plurality of shaped abrasive particles includes exposing the plurality of shaped abrasive particles to an electrostatic force.
  • the method may be implemented such that the lineal aligned shaped abrasive particle structure is magnetic responsive. Orienting the plurality of shaped abrasive particles includes exposing the lineal aligned shaped abrasive particles to a magnetic force.
  • the method may be implemented such that a face of a first shaped abrasive particle is parallel to a corresponding face of a second shaped abrasive particle.
  • the method may be implemented such that the lineal aligned shaped abrasive particle structure also includes a second plurality of particles. The second plurality of particles are different from the plurality of particles.
  • the method may be implemented such that coupling the filament to the plurality of abrasive particles includes dispensing a curable material across each of the plurality of shaped abrasive particles and curing the curable material to form the filament.
  • the method may be implemented such that coupling the filament to the plurality of abrasive particles includes adhering the filament to each of the plurality of shaped abrasive particles.
  • the method may be implemented such that the perimeter includes an equilateral shape, an equiangular shape, a star shape, a lens-shape, a lune-shape, a circular sector or a circular segment, an arcuate shape.
  • a bonded abrasive article precursor mixture is presented that includes a plurality of lineal aligned abrasive particle structures.
  • Each of the lineal aligned abrasive particle structure includes a plurality of shaped abrasive particles and a filament that is coupled to each of the shaped abrasive particles.
  • Each of the shaped abrasive particles are spaced apart along the filament.
  • the precursor mixture also includes a bond precursor material.
  • the precursor mixture may be implemented such that the bond precursor material is a resin bond precursor material.
  • the precursor mixture may be implemented such that the bond precursor material is a vitreous bond precursor material.
  • the precursor mixture may be implemented such that the filament is coupled to each of the shaped abrasive particles along a face of the shaped abrasive particles.
  • the precursor mixture may be implemented such that the filament is coupled to each of the shaped abrasive particles along an edge of the shaped abrasive particles.
  • the precursor mixture may be implemented such that the filament is coupled to each of the shaped abrasive particles at a vertex of the shaped abrasive particles.
  • the precursor mixture may be implemented such that a subset of the plurality of shaped abrasive particles are spaced apart according to a spacing pattern. [00213] The precursor mixture may be implemented such that the spacing pattern is substantially similar spacing between adjacent particles along the filament. [00214] The precursor mixture may be implemented such that the filament includes a material that sublimes in a temperature range required to cure the bond precursor material. [00215] The precursor mixture may be implemented such that the filament includes a material that melts in a temperature range required to cure the bond precursor material. [00216] The precursor mixture may be implemented such that the lineal aligned abrasive particle structures each include at least 4 shaped abrasive particles.
  • the precursor mixture may be implemented such that the lineal aligned abrasive particle structures each include at least 10 shaped abrasive particles. [00218] The precursor mixture may be implemented such that the lineal aligned abrasive particle structures each include at least 50 shaped abrasive particles. [00219] The precursor mixture may also includes a pore inducing material. [00220] The precursor mixture may be implemented such that the perimeter of each of the plurality of abrasive particles includes an equilateral shape, an equiangular shape, a star shape, a lens-shape, a lune-shape, a circular sector or a circular segment, an arcuate shape.
  • the precursor mixture may be implemented such that the perimeter includes a triangle, a parallelogram, rectangle, a square, a star, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, a cross, a dog-bone, or a rod.
  • a coated abrasive article is presented that includes a backing and a plurality of lineal aligned abrasive particle structures each coupled to the backing.
  • Each of the lineal aligned abrasive particle structures includes a filament and a plurality of shaped abrasive particles coupled to the filament. The plurality of shaped abrasive particles are spaced apart along the filament.
  • the coated abrasive article may be implemented such that it includes a make coat coupled to the backing.
  • the lineal aligned abrasive particle structures are embedded into the make coat.
  • the make coat includes a resin.
  • the coated abrasive article may be implemented such that the filament is at least partially melted into the make coat.
  • the coated abrasive article may be implemented such that the filament is at least partially covered by make coat.
  • the coated abrasive article may be implemented such that the plurality of shaped abrasive particles are spaced apart along the filament in a spacing pattern.
  • the coated abrasive article may be implemented such that the spacing pattern includes regular spacing between adjacent particles.
  • the coated abrasive article may be implemented such that each of the plurality of shaped abrasive particles has a face.
  • the plurality of shaped abrasive particles are aligned such that adjacent faces are aligned.
  • the coated abrasive article may be implemented such that the faces of adjacent particles are substantially parallel.
  • the coated abrasive article may be implemented such that the plurality of shaped abrasive particles are aligned with respect to the filament.
  • the coated abrasive article may be implemented such that the plurality of shaped abrasive particles are substantially orthogonal to the filament.
  • the coated abrasive article may be implemented such that the plurality of shaped abrasive particles are angled with respect to the filament. [00233] The coated abrasive article may also include secondary particles embedded in the make coat. [00234] The coated abrasive article may also include a size coat. [00235] The coated abrasive article may also include a supersize coat. [00236] The coated abrasive particle may be implemented such that the filament is coupled to each of the shaped abrasive particles along a face of the shaped abrasive particles.
  • the coated abrasive particle may be implemented such that the filament is coupled to each of the shaped abrasive particles along an edge of the shaped abrasive particles.
  • the coated abrasive particle may be implemented such that the filament is coupled to each of the shaped abrasive particles at a vertex of the shaped abrasive particles.
  • the coated abrasive particle may be implemented such that each of the plurality of shaped abrasive particles includes a perimeter of an equilateral shape, an equiangular shape, a star shape, a lens-shape, a lune-shape, a circular sector or a circular segment, an arcuate shape.
  • the coated abrasive particle may be implemented such that each of the plurality of shaped abrasive particles includes a perimeter includes a triangle, a parallelogram, a rectangle, a square, a star, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, a cross, a dog- bone, or a rod.
  • a method of making an abrasive article is presented. The method includes providing a plurality of lineal aligned abrasive particle structures. Each of the lineal aligned abrasive particle structures includes a filament coupled to each of a plurality of abrasive particles.
  • Each of the abrasive particles have a shape.
  • the abrasive particles are spaced along the filament according to a spacing pattern.
  • the method also includes embedding the lineal aligned abrasive particle structures within a make coat on a backing.
  • the method also includes curing the make coat. [00242]
  • the method may be implemented such that the lineal aligned abrasive particle structures are place on the make coat prior to complete curing of the make coat.
  • the method may be implemented such that the filament at least partially melts into the make coat during curing.
  • the method may also include applying a size coat.
  • the method may be implemented such that the filament is adhered to the size coat.
  • the method may also include applying a supersize coat. [00247] The method may be implemented such that the spacing pattern includes regular spacing between adjacent shaped abrasive particles. [00248] The method may be implemented such that each of the plurality of shaped abrasive particles has a face. The plurality of shaped abrasive particles are aligned such that adjacent faces are aligned. [00249] The method may be implemented such that the faces of adjacent particles are substantially parallel. [00250] The method may be implemented such that the plurality of shaped abrasive particles are aligned with respect to the filament. [00251] The method may be implemented such that the plurality of shaped abrasive particles are substantially orthogonal to the filament.
  • the method may be implemented such that the plurality of shaped abrasive particles are angled with respect to the filament. [00253] The method may also include having secondary particles embedded in the make coat. [00254] The method may be implemented such that the filament is coupled to each of the shaped abrasive particles along a face of the shaped abrasive particles. [00255] The method may be implemented such that the filament is coupled to each of the shaped abrasive particles along an edge of the shaped abrasive particles. [00256] The method may be implemented such that the filament is coupled to each of the shaped abrasive particles at a vertex of the shaped abrasive particles.
  • the method may be implemented such that the each of the shaped abrasive particles has a perimeter that includes an equilateral shape, an equiangular shape, a star shape, a lens-shape, a lune-shape, a circular sector or a circular segment, an arcuate shape.
  • the method may be implemented such that the each of the shaped abrasive particles has a perimeter that includes a triangle, a parallelogram, rectangle, square a star, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, a cross, a dog-bone, or a rod.
  • the method may also include coating the abrasive particles with a magnetically responsive material and orienting the abrasive particles by providing a magnetic field such that a majority of the abrasive particles are each oriented with a cutting face in the same direction.
  • a magnetically responsive material such that a majority of the abrasive particles are each oriented with a cutting face in the same direction.
  • SAP shaped abrasive particles
  • SAP Shaped abrasive particles
  • LAPS lineal abrasive particle structures
  • SAP in excess of those accommodated into the tool's cavities were removed by brushing.
  • a clear polyester string obtained from Maxcatch, Qingdao, CN under trade designation M Maxiumcatch) with about 0.2mm diameter was drawn carefully to pass through the central open of the SAP to form a SAP string.
  • a phenolic make resin comprising 49.2 parts phenolic resin (Phenol-formaldehyde resin having a phenol to formaldehyde molar ratio of 1:1.5- 2.1, and catalyzed with 2.5 percent by weight potassium hydroxide.); 40.6 parts by weight of calcium carbonate (calcium carbonate commercially available as Hubercarb Q325 from Hubercarb Engineered Materials, Atlanta Georgia.); and 10.2 parts by weight of deionized water, was applied to the string with a paint brush. The sample was dried at 90 degree Celsius for 20 minutes, and then the string was pulled out from the production tool, cured at 102 degree Celsius for 8 hours. [00263] FIG.
  • FIG. 9A illustrates an image of lineal abrasive particle comprising SAP with an open before applying make resin.
  • FIG.9B illustrates an image of lineal abrasive particle comprising SAP with an open after applying make resin.
  • Example 2 LAPS Formed Using a Tool [00264] Shaped abrasive particles (SAP) were prepared according to the disclosure of U.S. Pat.
  • No.8,142,531 (Adefris et al.) having nominal equal side lengths of approximately 1.30 mm and a thickness of 0.27 mm, and a sidewall angle of 98 degrees
  • LAPS lineal abrasive particle structures
  • SAP in excess of those accommodated into the tool's cavities were removed by brushing.
  • SAP in the production tool are illustrated in FIGS.9C and 9D.
  • Threads of hot melt resin 3792LM, 3M Company, Saint Paul, MN
  • a hot melt glue gun (3M Scotch-Weld Hot Melt Applicator LT, 3M Company, Saint Paul, MN) onto the pre-aligned SAP to join the SAP onto the thread.
  • the treads together with the SAP were removed from the production tool to form the LAPS.
  • SAP shaped abrasive particles
  • SAP shaped abrasive particles
  • LAPS lineal abrasive particle structures
  • hot melt glue gun 3M Scotch-Weld Hot Melt Applicator LT, 3M Company, Saint Paul, MN
  • a continuous filament nonwoven web was made similarly to that of Example 1 of U.S. Pat. No.4,227,350.
  • Polycaprolactam Nylon 6, available commercially under the trade designation “B27 E” from BASF Corporation, Polymers Division of Mt.
  • Filaments extruded from the spinneret were permitted to fall into the quench bath where they undulated and coiled between 4 inch (10.16 cm) diameter, 60 inch (1.52 m) long smooth-surfaced rolls. Both rolls were positioned in the bath with their axes of rotation about 2 inches (5.1 cm) below the surface of the bath, and the rolls were rotated in opposite directions at a rate of about 9 feet/minute (2.74 m/minute) surface speed. The rolls were spaced to lightly compress the surfaces of the resultant extruded web, providing a flattened but not densified surface on both sides. The polymer was extruded at a rate of about 700 lb./hr.
  • the resulting web weighed about 14.8 g/24 in 2 (0.956 kg/m 2 ) and had a void volume of about 95%.
  • the filament diameter averaged about 0.38 cm (0.015 in).
  • the web was carried from the quench bath around one of the rolls and excess water was removed from the web by drying with a room temperature (about 23° C) air blast. [00270] The dried web thus formed was later converted to an abrasive composition by applying a make coating, LAAPS coating, and size coating.
  • the make and size coating used the same resin which was Alberdingk U 6150, a solvent-free, aliphatic polycarbonate polyurethane dispersion available from Alberdingk Boley GmbH, Krefeld, Germany.
  • the make coating was applied to the web using a paint roller to achieve a coating weight of 522 gsm.
  • LAAPS were drop coated on the wet web at 176 gsm and dried in an oven at 75° Celsius for 5 minutes.
  • the sample was then taken out of the oven and a size coating was applied using a paint roller at a coating weight of 94 gsm and fully dried in an oven at 75° Celsius for 3 hours.
  • the resultant nonwoven abrasive is shown in Figure 10.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Polishing Bodies And Polishing Tools (AREA)

Abstract

Une structure linéaire de particules abrasives alignées est présentée. La structure comprend une pluralité de particules abrasives façonnées. Chaque particule abrasive façonnée comprend un périmètre et une épaisseur. Le périmètre de chaque particule abrasive façonnée est sensiblement le même. L'épaisseur de chaque particule abrasive façonnée est sensiblement la même. La structure comprend également un filament accouplé à chaque particule de la pluralité de particules abrasives façonnées. La pluralité de particules abrasives façonnées sont régulièrement espacées le long du filament.
PCT/US2022/024992 2021-04-16 2022-04-15 Structures linéaires de particules abrasives alignées WO2022221646A1 (fr)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5863305A (en) * 1996-05-03 1999-01-26 Minnesota Mining And Manufacturing Company Method and apparatus for manufacturing abrasive articles
US8142531B2 (en) * 2008-12-17 2012-03-27 3M Innovative Properties Company Shaped abrasive particles with a sloping sidewall
US20130125477A1 (en) * 2010-08-04 2013-05-23 3M Innovative Properties Company Intersecting plate shaped abrasive particles
WO2018057465A1 (fr) * 2016-09-26 2018-03-29 3M Innovative Properties Company Articles abrasifs non tissés ayant des particules abrasives à orientation électrostatique et leurs procédés de fabrication
US20190233694A1 (en) * 2012-04-04 2019-08-01 3M Innovative Properties Company Abrasive particles, method of making abrasive particles, and abrasive articles
WO2020084483A1 (fr) * 2018-10-26 2020-04-30 3M Innovative Properties Company Article abrasif comprenant une bande souple
WO2021245494A1 (fr) * 2020-06-04 2021-12-09 3M Innovative Properties Company Particules abrasives façonnées et leurs procédés de fabrication

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5863305A (en) * 1996-05-03 1999-01-26 Minnesota Mining And Manufacturing Company Method and apparatus for manufacturing abrasive articles
US8142531B2 (en) * 2008-12-17 2012-03-27 3M Innovative Properties Company Shaped abrasive particles with a sloping sidewall
US20130125477A1 (en) * 2010-08-04 2013-05-23 3M Innovative Properties Company Intersecting plate shaped abrasive particles
US20190233694A1 (en) * 2012-04-04 2019-08-01 3M Innovative Properties Company Abrasive particles, method of making abrasive particles, and abrasive articles
WO2018057465A1 (fr) * 2016-09-26 2018-03-29 3M Innovative Properties Company Articles abrasifs non tissés ayant des particules abrasives à orientation électrostatique et leurs procédés de fabrication
WO2020084483A1 (fr) * 2018-10-26 2020-04-30 3M Innovative Properties Company Article abrasif comprenant une bande souple
WO2021245494A1 (fr) * 2020-06-04 2021-12-09 3M Innovative Properties Company Particules abrasives façonnées et leurs procédés de fabrication

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