COATED ABRASIVE ARTICLES AND METHODS OF MAKING COATED ABRASIVE ARTICLES

Abstract

A coated abrasive article is presented. The coated abrasive article includes a backing having first and second opposed major surfaces. The coated abrasive article also includes a make layer bonded to the first major surface. The coated abrasive article also includes abrasive particles directly bonded to the make layer. The abrasive particles are at least partially embedded in the make layer. The coated abrasive article also includes a size layer directly bonded to the make layer, and abrasive particles. One of the make layer and size layer comprise a patterned coating.

Description

BACKGROUND

Coated abrasive articles are broadly useful for abrading, finishing, or grinding a wide variety of materials and surfaces in the manufacturing of goods. Generally, coated abrasive articles comprise a backing, a first layer of cured resinous adhesive layer (make layer) applied over one major surface of the backing, abrasive particles, a second cured resinous adhesive layer (size layer), and optionally a third cured resinous adhesive layer (supersize layer). In some situations, grinding aids are used to improve abrasion performance and are typically used as an additive in the formulation of at least one of the foregoing resinous adhesive layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of an exemplary coated abrasive article according to the present disclosure.

FIG. 1B is a top view of an exemplary coated abrasive article.

FIGS. 2A and 2B illustrate methods and results of pattern coating an abrasive article in accordance with embodiments described herein.

FIG. 3 is a diagrammatic view of a method of making a pattern coated abrasive article in accordance with embodiments described herein.

FIGS. 4A-4D illustrate pattern coated abrasive articles in accordance with embodiments described herein.

FIG. 5 illustrates a method of using a pattern coated abrasive article in accordance with embodiments described herein.

FIG. 6 illustrates a coated abrasive article in accordance with embodiments described herein.

FIGS. 7A-7I illustrate coated abrasive articles made in accordance with the Examples.

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale.

DETAILED DESCRIPTION

Coated abrasive articles are known in the art, and often include abrasive particles embedded in a make coat layer on a backing and coated with a size coat that can reduce shelling of the abrasive particles from the backing. Supersize or other functional layers, including functional layers as well as primer or laminate layers, can also be added to add functionality and/or change parameters of a coated abrasive article.

Generally, pattern coated abrasive articles exhibit better abrading efficiency than non-patterned coated abrasive articles. This may result from more efficient swarf removal from a workpiece, judicious engineering of the abrasive area, or the facilitation of lubricant and/or grinding aid to the work surface.

As used herein, a “pattern” on a coated abrasive article refers to an intentional placement of material on a backing, such that a portion of the backing, or a portion of the previous layer, remains uncoated. A patterned make coat, therefore, covers some, but not all, of a backing, such that portions of backing remain uncovered. A patterned layer of abrasive particles, similarly, may result in some, but not all, of a make coat being covered with abrasive particles. A pattern includes intentional designs with or without a repeating unit. A pattern may extend from a center of an abrasive disc, or a center axis of an abrasive belt, to an edge of an abrasive disc or abrasive belt. Pattern-coating is intended to include any suitable method of forming well-defined areas of a given material coating as well as open areas devoid of a given material coating. The patterned abrasive area can therefore be designed independent of any pattern present on the fabric substrate, to optimize both abrasive performance, dust extraction and antiloading properties. A pattern may include lines, swirls, polygonal shapes, letters, or numbers. Additionally, other text or product information could also be provided on the coated abrasive article. A pattern may also include color, such that portions of a final coated abrasive article have a first color, and portions of a final coated abrasive article have a second color.

It is also known in the art that abrasive particles may be pattern coated and/or aligned on a backing surface. In some embodiments, patterned drop coating can be achieved using an alignment tool by methods analogous to that described in PCT Pat. Appl. Publ. Nos. 2016/205133 (Wilson et al.), 2016/205267 (Wilson et al.), 2017/007703 (Wilson et al.), 2017/007714 (Liu et al.). Transfer coating using a tool having patterned cavities can be analogous to that described in U.S. Pat. Appln. Publ. No. 2016/0311081 A1 (Culler et al.). In some embodiments, abrasive particles can be applied onto the make layer through a patterned mesh or sieve.

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 et al.), and U.S. Provisional Nos. 62/914,778 filed on Oct. 14, 2019 and 62/875,700 filed Jul. 18, 2019, and 62/924,956, filed Oct. 23, 2019.

The terms “cured”, “curing” and “curable” refer to joining polymer chains together by covalent chemical bonds, usually via crosslinking molecules or groups, to form a network. Therefore, in this disclosure the terms “cured” and “crosslinked” may be used interchangeably.

FIGS. 1A and 1B illustrate views of a coated abrasive article in accordance with embodiments described herein.

Referring now to FIG. 1A, coated abrasive article 100 comprises backing 110 having first major surface 112 and second major surface 114 opposite first major surface 112. Make layer 120 is disposed on and bonded to first major surface 112. Abrasive particles 130 and abrasive particles 130 are bonded to make layer 120. A size layer 140 is disposed over and bonded to make layer 120, and abrasive particles 130. Optional supersize layers or other functional layers are disposed over and bonded to size layer 140.

Referring now to FIG. 1B, one example form of a coated abrasive article is a coated abrasive disc 150. However, other coated abrasive articles are also envisioned, such as abrasive belts.

Exemplary suitable materials for the backing include polymeric films, metal foils, woven fabrics, knitted fabrics, paper, vulcanized fiber, nonwovens, foams, screens, mesh, laminates, combinations thereof, and treated versions thereof. The coated abrasive article may be in the form of a sheet, disc, belt, pad, or roll. The backing may be rigid, semi-rigid, or flexible. In some embodiments, the backing should be sufficiently flexible to allow the coated abrasive article to be formed into a loop to make an abrasive belt that can be run on suitable grinding equipment. For applications where stiffness of the backing is desired, a flexible backing may also be used by affixing it to a rigid backup pad mounted to the grinding tool. For off-hand grinding applications where stiffness and cost are concerns, vulcanized fiber backings are typically preferred. In some embodiments, the backing may be circular and may comprise a continuous uninterrupted disc, while in others it may have a central arbor hole for mounting. Likewise, the circular backing may be flat or it may have a depressed central hub, for example, a Type 27 depressed center disc. In some embodiments, the backing has a mechanical fastener, or adhesive fastener securely attached to a major surface opposite the abrasive layer.

The make layer, size layer and the optional supersize layer comprise a resinous binder which may be the same or different. Exemplary suitable binders can be prepared from corresponding binder precursors such as thermally curable resins, radiation-curable resins, and combinations thereof.

Binder precursors (e.g., make layer precursors and/or size layer precursors) may comprise, for example, glue, phenolic resin, aminoplast resin, urea-formaldehyde resin, melamine-formaldehyde resin, urethane resin, free-radically polymerizable polyfunctional (meth)acrylate (e.g., aminoplast resin having pendant α,β-unsaturated groups, acrylated urethane, acrylated epoxy, acrylated isocyanurate), epoxy resin (including bis-maleimide and fluorene-modified epoxy resins), isocyanurate resin, and mixtures thereof. Of these, phenolic resins are preferred, especially when used in combination with a vulcanized fiber backing.

Phenolic resins are generally formed by condensation of phenol and formaldehyde, and are usually categorized as resole or novolac phenolic resins. Novolac phenolic resins are acid-catalyzed and have a molar ratio of formaldehyde to phenol of less than 1:1. Resole (also resol) phenolic resins can be catalyzed by alkaline catalysts, and the molar ratio of formaldehyde to phenol is greater than or equal to one, typically between 1.0 and 3.0, thus presenting pendant methylol groups. Alkaline catalysts suitable for catalyzing the reaction between aldehyde and phenolic components of resole phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, and sodium carbonate, all as solutions of the catalyst dissolved in water.

Resole phenolic resins are typically coated as a solution with water and/or organic solvent (e.g., alcohol). Typically, the solution includes about 70 percent to about 85 percent solids by weight, although other concentrations may be used. If the solids content is very low, then more energy is required to remove the water and/or solvent. If the solids content is very high, then the viscosity of the resulting phenolic resin is too high which typically leads to processing problems.

Phenolic resins are well-known and readily available from commercial sources. Examples of commercially available resole phenolic resins useful in practice of the present disclosure include those marketed by Durez Corporation under the trade designation VARCUM (e.g., 29217, 29306, 29318, 29338, 29353); those marketed by Ashland Chemical Co. of Bartow, Fla. under the trade designation AEROFENE (e.g., AEROFENE 295); and those marketed by Kangnam Chemical Company Ltd. of Seoul, South Korea under the trade designation PHENOLITE (e.g., PHENOLITE TD-2207).

Binder precursors can further comprise optional additives such as, for example, fillers (including grinding aids), fibers, lubricants, wetting agents, surfactants, pigments, dyes, coupling agents, resin curatives, plasticizers, antistatic agents, and suspending agents. Examples of fillers suitable for this invention include wood pulp, vermiculite, and combinations thereof, metal carbonates, such as calcium carbonate, e.g., chalk, calcite, marl, travertine, marble, and limestone, calcium magnesium carbonate, sodium carbonate, magnesium carbonate; silica, such as amorphous silica, quartz, glass beads, glass bubbles, and glass fibers; silicates, such as talc, clays (montmorillonite), feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate; metal sulfates, such as calcium sulfate, barium sulfate, sodium sulfate, aluminum sodium sulfate, aluminum sulfate; gypsum; vermiculite; wood flour; aluminum trihydrate; metal oxides, such as calcium oxide (lime), aluminum oxide, titanium dioxide, and metal sulfites, such as calcium sulfite.

Binder precursors may be applied by any known coating method, including, for example, including roll coating, extrusion die coating, curtain coating, knife coating, gravure coating, and spray coating.

The basis weight of the make layer utilized may depend, for example, on the intended use(s), type(s) and grade(s) of abrasive particles, and nature of the coated abrasive disc being prepared, but typically will be in the range of from 1, 2, 5, 10, or 15 grams per square meter (gsm) to 20, 25, 100, 200, 300, 400, or even 600 gsm.

FIG. 2A is a method of making a pattern coated abrasive article in accordance with embodiments described herein. Method 200 may be useful for providing a pattern coated abrasive article.

Details concerning general manufacture of coated abrasive articles can be found in, for example, U.S. Pat. No. 4,734,104 (Broberg); U.S. Pat. No. 4,737,163 (Larkey); U.S. Pat. No. 5,203,884 (Buchanan et al.); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,378,251 (Culler et al.); U.S. Pat. No. 5,417,726 (Stout et al.); U.S. Pat. No. 5,436,063 (Follett et al.); U.S. Pat. No. 5,496,386 (Broberg et al.); U.S. Pat. No. 5,609,706 (Benedict et al.); U.S. Pat. No. 5,520,711 (Helmin); U.S. Pat. No. 5,954,844 (Law et al.); U.S. Pat. No. 5,961,674 (Gagliardi et al.); U.S. Pat. No. 4,751,138 (Bange et al.); U.S. Pat. No. 5,766,277 (DeVoe et al.); U.S. Pat. No. 6,077,601 (DeVoe et al.); U.S. Pat. No. 6,228,133 (Thurber et al.); and U.S. Pat. No. 5,975,988 (Christianson).

As described above, it may be helpful to have an abrasive article with abrasive particles applied in a pattern. It is contemplated that, in some embodiments, it may be more efficient to apply some layers in a coated abrasive article evenly, and only a subset of the layers with the desired pattern. It may also be helpful to have the pattern applied in all, or almost all layers. However, applying the pattern in a subset of layers may provide functional differences in abrasive efficiency, or it may serve to associate an abrasive article with a specific manufacturer, or to detect counterfeit products from a different manufacturer. Additionally, pattern coating may require special tooling. Reducing a number of coatings that require a pattern may, therefore, reduce the cost of manufacturing. However, improvements of pattern coating can still be seen when only a subset of the coatings are patterned. For example, a patterned make coat with a full size coat helps resist shelling.

In block 210, a backing is provided. Exemplary suitable materials for the backing include polymeric films, metal foils, woven fabrics, knitted fabrics, paper, vulcanized fiber, nonwovens, foams, screens, mesh, laminates, combinations thereof, and treated versions thereof. Optionally, coated abrasive articles may further comprise, for example, a backsize (that is, a coating on the major surface of the backing opposite the major surface having the abrasive coat), a presize or a tie layer (that is, a coating between the abrasive coat and the major surface to which the abrasive coat is secured), and/or a saturant which coats both major surfaces of the backing. The backing may also have a laminate applied, as described, for example, in co-owned, pending U.S. Provisional Applications 62/945,242 and 62/945,244, both filed on Dec. 9, 2019.

In block 220, a make coat is provided. The make coat may is applied as a curable make layer deposited on a major surface of a backing. Applying the make coat may be accomplished by any suitable method including, for example, spray coating, curtain coating, slot coating, roll coating, and/or knife coating. Coating weights will depend on the application, and will be apparent to those of skill in the art. In one embodiment, the make coat precursor is applied on the backing with a pattern, as indicated in block 222. For example, a make coat precursor may be spray coated through a mask, such that make coat precursor contacts and covers the backing substrate in a desired pattern. However, in other embodiments, the make coat precursor is applied as an even coating, as indicated in block 224, such that the entire backing substrate receives a substantially even coating of make coat precursor. Other methods are also possible including gravure coating, flexographic printing, patterned roll-coating, screen printing or stencil printing, in some embodiments.

In block 230, abrasive particles are provided. As discussed herein, abrasive particles can include crushed abrasive particles, platey abrasive particles, and/or shaped abrasive particles. Applying abrasive particles may include, in some embodiments, providing abrasive particles of a first size, and a second size. Providing abrasive particles may also include, in some embodiments, providing multiple types of abrasive particles, such as shaped abrasive particles and crushed abrasive particles.

In some preferred embodiments, at least some of the abrasive particles can be deposited according to a predetermined pattern. Examples of patterns include rectangular grids, parallel stripes, hexagonal grids, parallel wavy lines, checkerboard, spiral, and an array of partially-filled circles. Some example patterns are illustrated in U.S. Provisional Applications 62/945,242, filed on Dec. 9, 2019.

In an embodiment where a patterned make coat precursor is applied in block 220, it may not be necessary to deposit abrasive particles in a pattern, as particles landing on areas of the backing without make coat precursor will not adhere to the backing. Therefore, it may be possible to apply abrasives evenly over a make coat precursor, as indicated in block 234.

However, it is also expressly contemplated that, regardless of whether a make coat is applied evenly or in a pattern, there may be benefits to applying abrasive particles in a pattern, as indicated in block 232. For example, particles may be applied more densely in different areas of an abrasive article. Additionally, particles of different sizes may be applied in different patterns. Further, shaped abrasive particles may be applied in a different pattern, on the same article, than crushed abrasive particles. As used herein, the term “pattern” refers to the overall pattern formed by the abrasive particles, not to the individual abrasive particles that make up the pattern.

After, or during, deposition of abrasive particles, the curable make layer precursor is sufficiently cured (e.g., using heat and/or electromagnetic radiation) such that the make layer and the abrasive particles are secured to the backing.

In block 240, a size layer is applied. Applying a size layer may include, in some embodiments, applying a size layer precursor that is later cured to create the size layer. The size layer may be applied on a fully, or at least partially cured make layer. Coating may be accomplished by any suitable method including, for example, spray coating, curtain coating, slot coating, roll coating, and/or knife coating. Coating weights will depend on the application, and will be apparent to those of skill in the art. The curable size layer precursor is cured, for example, using heat and/or electromagnetic radiation. The size coat, in one embodiment, is applied in a pattern, as indicated in block 242. The size coat may be applied as a pattern regardless of whether the make coat or abrasive particles are pattern coated. For example a size coat may be applied in a pattern to indicate a manufacturer or grade of the abrasive article. Additionally, a size coat may be applied as an even coating, as indicated in block 244, over a pattern coated layer of abrasive particles and/or a pattern coated make coat layer. Because of the relative size of abrasive particles compared to an abrasive article, an evenly coated size coat may at least partially obfuscate patterning of the abrasive particles, creating an abrasive article that looks similar to a non-pattern coated abrasive article.

In block 250, an additional functional layer may be provided. A functional layer may be applied in addition to, or as, a supersize coat. The functional layer may be deposited in a pattern, as indicated in block 252, which may be the same or different from any abrasive particle pattern layer. Additionally, in some embodiments, the functional layer is applied in an even coating, as indicated in block 254. For example, it may be desired to have grinding aid, for example, evenly deposited on an article. Additionally, the functional layer may also include grinding aids and/or anti-loading materials. For example, a supersize coat may be applied in a pattern to indicate a manufacturer or grade of the abrasive article.

A grinding aid is defined as particulate material, the addition of which to an abrasive article has a significant effect on the chemical and physical processes of abrading. In particular, it is believed that the grinding aid may: (1) decrease the friction between the abrasive particles and the workpiece being abraded; (2) prevent the abrasive particles from “capping”, i.e., prevent metal particles from becoming welded to the tops of the abrasive particles; (3) decrease the interface temperature between the abrasive particles and the workpiece; (4) decrease the grinding forces; and/or (5) have a synergistic effect of the mechanisms mentioned above. In general, the addition of a grinding aid increases the useful life of the coated abrasive article. Grinding aids encompass a wide variety of different materials and can be inorganic or organic.

Exemplary grinding aids may include inorganic halide salts, halogenated compounds and polymers, and organic and inorganic sulfur-containing materials. Exemplary grinding aids, which may be organic or inorganic, include waxes, halogenated organic compounds such as chlorinated waxes like tetrachloronaphthalene, pentachloronaphthalene, and polyvinyl chloride; halide salts such as sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluorides, potassium chloride, magnesium chloride; and metals and their alloys such as tin, lead, bismuth, cobalt, antimony, cadmium, iron, and titanium. Examples of other grinding aids include sulfur, organic sulfur compounds, graphite, and metallic sulfides, organic and inorganic phosphate-containing materials. A combination of different grinding aids may be used.

Preferred grinding aids include halide salts, particularly potassium tetrafluoroborate (KBF₄), cryolite (Na₃AlF₆), and ammonium cryolite [NH₄)₃AlF₆]. Other halide salts that can be used as grinding aids include sodium chloride, potassium cryolite, sodium tetrafluoroborate, silicon fluorides, potassium chloride, and magnesium chloride. Other preferred grinding aids are those in U.S. Pat. No. 5,269,821 (Helmin et al.), which describes grinding aid agglomerates comprised of water soluble and water insoluble grinding aid particles. Other useful grinding aid agglomerates are those wherein a plurality of grinding aid particles are bound together into an agglomerate with a binder. Agglomerates of this type are described in U.S. Pat. No. 5,498,268 (Gagliardi et al.).

Examples of halogenated polymers useful as grinding aids include polyvinyl halides (e.g., polyvinyl chloride) and polyvinylidene halides such as those disclosed in U.S. Pat. No. 3,616,580 (Dewell et al.); highly chlorinated paraffin waxes such as those disclosed in U.S. Pat. No. 3,676,092 (Buell); completely chlorinated hydrocarbons resins such as those disclosed in U.S. Pat. No. 3,784,365 (Caserta et al.); and fluorocarbons such as polytetrafluoroethylene and polytrifluorochloroethylene as disclosed in U.S. Pat. No. 3,869,834 (Mullin et al.).

Inorganic sulfur-containing materials useful as grinding aids include elemental sulfur, iron(II) sulfide, cupric sulfide, molybdenum sulfide, potassium sulfate, and the like, as variously disclosed in U.S. Pat. No. 3,833,346 (Wirth), U.S. Pat. No. 3,868,232 (Sioui et al.), and U.S. Pat. No. 4,475,926 (Hickory). Organic sulfur-containing materials (e.g., thiourea) for use in the invention include those mentioned in U.S. Pat. No. 3,058,819 (Paulson).

It is also within the scope of this disclosure to use a combination of different grinding aids and, in some instances, this may produce a synergistic effect. The above-mentioned examples of grinding aids are meant to be a representative showing of grinding aids, and they are not meant to encompass all grinding aids.

A coated abrasive article may also include grinding aid particles arranged randomly, in a single predetermined pattern, or in multiple different patterns. At least a portion of the grinding aid particles may be positioned such that a pattern formed by these grinding aid particles includes a plurality of parallel lines and/or a grid pattern. As a further example, at least a portion of grinding aid particles can be positioned such that a pattern formed by these grinding aid particles includes a plurality of circles (hollow or filled). Likewise, at least a portion of grinding aid particles may be arranged in a spiral, checkerboard, or striped (in any orientation). The pattern of grinding aid particles may be the same, or different, as the pattern of the abrasive particles. Grinding aid particles, whether patterned or not, may be deposited as part of the abrasive particle deposition, discussed above with respect to step 230, or as part of a supersize coating, applied as part of the functional coating described in block 250.

FIG. 2B is a flow chart 260 illustrating the results of including patterns in different applied layers on a backing. Flow chart 260 assumes a single pattern is applied at any of the layers, and that, for multiple layers, the same pattern is applied. However, it is expressly contemplated that a pattern of abrasive particles may differ than a patterned size coat, for example. Additionally, FIG. 2B only illustrates the resulting abrasive article 270 from applying patterned or evenly coated make layer 262, abrasive particle layer 264, or size layer 266. However, it is expressly contemplated that supersize or additional functional layers are also contemplated, which may be treated similarly to the size layer 266.

FIG. 3 is a diagrammatic view of a method of making a pattern coated abrasive article in accordance with embodiments described herein. FIG. 3 illustrates a diagram 300 showing deposition of different layers on a backing 320. Layers are deposited from one of several dispensers 310. However, while several dispensers 310 are discussed, it is contemplated that, in some embodiments, one dispenser 310 may dispense multiple layers of material.

An abrasive article has a backing 320 that may undergo one or more pre-treatments or receive one or more primer layers. Primer layers and pretreatments may change a property of backing 320, for example changing a stiffness of backing 320 to be more, or less stiff than without a pretreatment or primer layer.

A first dispenser 310 dispenses a make coat 330, or a make coat precursor that can be cured into make coat 330, onto backing 320. Make coat 330 may be deposited directly onto backing 320, or may be deposited onto a laminate which is directly deposited onto backing 320, as described, for example, in U.S. Provisional Applications 62/945,242 and 62/945,244, both filed on Dec. 9, 2019. Make coat 330, or make coat precursor, may be deposited on backing 320 as an even coating, or as an even layer over the surface of backing 320, in one embodiment. In another embodiment, make coat 330, or make coat precursor, may be deposited in a pattern, such that some portions of backing 320 receive no make coat 330 or make coat precursor.

A second dispenser 310 dispenses abrasive particles 340. Abrasive particles 340 may be shaped abrasive particles, formed abrasive particles, crushed abrasive particles and/or platey abrasive particles. Dispensing abrasive particles 340 from a second dispenser 310 may include dispensing a first set of abrasive particles 340 and a second set of abrasive particles 340.

Abrasive particles 340 may be dispensed in a pattern by dispenser 310, such that some areas of an applied make layer 330, or some areas of applied backing 320 remain uncovered. It is expressly contemplated, as illustrated in FIG. 2B, that abrasive particles 340 may be deposited in a pattern regardless of whether make layer 330 is deposited in a pattern. However, if make layer 330 is applied in a pattern, and abrasive particles 340 are applied evenly, only abrasive particles 340 that embed within the pattern of make coat 330 will adhere to and become incorporated into the final abrasive article.

It is also contemplated that, while only one type and size of abrasive particles 340 is illustrated in FIG. 3, that, in some embodiments, a first and second set of abrasive particles are deposited. For example, the first and second set of abrasive particles may vary in type, selected from shaped, formed crushed, platey, or agglomerate. Additionally, or alternatively, the first and second set of abrasive particles may vary in size, composition, or deposition pattern.

A size coat 350, or size coat precursor is deposited on top of abrasive particles 340. Many size coats, either naturally or through the inclusion of a pigment, impart a color to an abrasive particle. Pattern coating a size coat 350 may, therefore, result in a visual pattern clearly visible to a user of the abrasive article. While it may be possible to detect a pattern of abrasive particles 340, in some embodiments abrasive particles 340 are small enough that the pattern is not readily visible. Since the pattern of abrasive particles 340 may change a quality or behavior of an abrasive article, a patterned size coat may be helpful to indicate to a user one or more attributes on the abrasive article, such as a grade or size of the abrasive particles.

One or more supersize coats 360 may be applied over size coat 350. Supersize coats may impart additional functionality, such as grinding aids, lubricants, or other particulates to the abrasive article. Supersize coats 360 may also impart a color or visual indication to the final abrasive article.

FIGS. 4A-4D illustrate pattern coated abrasive articles in accordance with embodiments described herein. 4A and 4B illustrate pattern coated abrasive discs coated with a supersize layer. FIG. 4C illustrates a mesh abrasive with an evenly coated size coating. FIG. 4D illustrates a mesh abrasive with a pattern coated size coating.

Abrasive particles used in embodiments herein, whether crushed or shaped, should have sufficient hardness and surface roughness to function as abrasive particles in an abrading process. Preferably, the abrasive particles have a Mohs hardness of at least 4, at least 5, at least 6, at least 7, or even at least 8.

Useful abrasive 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. Paul, Minn., black silicon carbide, green silicon carbide, titanium diboride, boron carbide, tungsten carbide, titanium carbide, cubic boron nitride, garnet, fused alumina zirconia, sol-gel derived ceramics (e.g., alumina ceramics doped with chromia, ceria, zirconia, titania, silica, and/or tin oxide), silica (e.g., quartz, glass beads, glass bubbles and glass fibers), feldspar, or flint. Examples of sol-gel derived crushed ceramic particles can be found in U.S. Pat. No. 4,314,827 (Leitheiser et al.), U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951 (Monroe et al.).

As discussed previously, the abrasive particles may be shaped (e.g., precisely-shaped) or random (e.g., crushed). Shaped abrasive particles and precisely-shaped abrasive particles can be prepared, for example, by a molding process using sol-gel technology as described in U.S. Pat. No. 5,201,916 (Berg); U.S. Pat. No. 5,366,523 (Rowenhorst (Re 35,570)); and U.S. Pat. No. 5,984,988 (Berg). U.S. Pat. No. 8,034,137 (Erickson et al.) describes alumina particles that have been formed in a specific shape, then crushed to form shards that retain a portion of their original shape features. Exemplary shapes of abrasive particles include crushed, pyramids (e.g., 3-, 4-, 5-, or 6-sided pyramids), truncated pyramids (e.g., 3-, 4-, 5-, or 6-sided truncated pyramids), cones, truncated cones, rods (e.g., cylindrical, vermiform), and prisms (e.g., 3-, 4-, 5-, or 6-sided prisms).

The abrasive particles may be independently sized according to an abrasives industry recognized specified nominal grade. Exemplary 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 (i.e., specified nominal grades) 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, 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, F2000, P12, P16, P20, P24, P30, P36, P40, P50, P60, P80, P100, P120, P150, P180, P220, P240, P280, P320, P360, P400, P500, P600, P800, P1000, P1200, P1500, P2000, and P2500. 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.

Examples of shaped abrasive particles can be found in U.S. Pat. No. 5,201,916 (Berg); U.S. Pat. No. 5,366,523 (Rowenhorst (Re 35,570)); and U.S. Pat. No. 5,984,988 (Berg). U.S. Pat. No. 8,034,137 (Erickson et al.) describes alumina crushed abrasive particles that have been formed in a specific shape, then crushed to form shards that retain a portion of their original shape features. In some embodiments, shaped alpha alumina particles are precisely-shaped (i.e., the particles have shapes that are at least partially determined by the shapes of cavities in a production tool used to make them. Details concerning such precisely-shaped abrasive particles and methods for their preparation can be found, for example, in U.S. Pat. No. 8,142,531 (Adefris et al.); U.S. Pat. No. 8,142,891 (Culler et al.); and U.S. Pat. No. 8,142,532 (Erickson et al.); and in U.S. Pat. Appl. Publ. Nos. 2012/0227333 (Adefris et al.); 2013/0040537 (Schwabel et al.); and 2013/0125477 (Adefris).

In embodiments wherein the abrasive particles are shaped as triangular platelets (or triangular frustopyramids), they may have a major surface with a vertex of 90 degrees (corresponding to a right triangle), or they may have a major surface with a vertex of greater than 90 degrees (corresponding to an obtuse triangle), although this is not a requirement. Examples include at least 91 degrees, at least 95 degrees, at least 100 degrees, at least 110 degrees, at least 120 degrees, or even at least 130 degrees.

In some preferred embodiments, the abrasive particles comprise platey crushed abrasive particles. Such abrasive particles can be obtained by known methods, from commercial suppliers, and/or by shape sorting such crushed abrasive particles; for example, using a shape-sorting table as is known in the art.

Examples of suitable abrasive particles include crushed abrasive particles comprising 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, St. Paul, Minn., brown aluminum oxide, blue aluminum oxide, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, garnet, titanium carbide, diamond, cubic boron nitride, fused alumina zirconia, iron oxide, chromia, zirconia, titania, quartz, feldspar, flint, emery, sol-gel-derived ceramic (e.g., alpha alumina), and combinations thereof. Further examples include crushed abrasive composites of abrasive particles (which may be platey or not) in a binder matrix, such as those described in U.S. Pat. No. 5,152,917 (Pieper et al.). Many such abrasive particles, agglomerates, and composites are known in the art.

Preferably, crushed abrasive particles comprise ceramic crushed abrasive particles such as, for example, sol-gel-derived polycrystalline alpha alumina particles. Ceramic crushed abrasive particles composed of crystallites of alpha alumina, magnesium alumina spinel, and a rare earth hexagonal aluminate may be prepared using sol-gel precursor alpha alumina particles according to methods described in, for example, U.S. Pat. No. 5,213,591 (Celikkaya et al.) and U.S. Publ. Pat. Appln. Nos. 2009/0165394 A1 (Culler et al.) and 2009/0169816 A1 (Erickson et al.).

Examples of sol-gel-derived abrasive particles from which crushed abrasive particles can be isolated, and methods for their preparation can be found, in U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951 (Monroe et al.). It is also contemplated that the crushed abrasive particles could comprise abrasive agglomerates such, for example, as those described in U.S. Pat. No. 4,652,275 (Bloecher et al.) or U.S. Pat. No. 4,799,939 (Bloecher et al.). In some embodiments, the crushed abrasive particles may be surface-treated with a coupling agent (e.g., an organosilane coupling agent) or other physical treatment (e.g., iron oxide or titanium oxide) to enhance adhesion of the crushed abrasive particles to a binder. The crushed abrasive particles may be treated before combining them with the binder, or they may be surface treated in situ by including a coupling agent to the binder.

Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Pat. No. 4,314,827 (Leitheiser); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,435,816 (Spurgeon et al.); U.S. Pat. No. 5,672,097 (Hoopman et al.); U.S. Pat. No. 5,946,991 (Hoopman et al.); U.S. Pat. No. 5,975,987 (Hoopman et al.); and U.S. Pat. No. 6,129,540 (Hoopman et al.); and in U.S. Publ. Pat. Appln. No. 2009/0165394 A1 (Culler et al.).

Surface coatings on the various abrasive particles may be used to improve the adhesion between the abrasive particles and a binder in abrasive articles, or can be used to aid in electrostatic deposition. In one embodiment, surface coatings as described in U.S. Pat. No. 5,352,254 (Celikkaya) in an amount of 0.1 to 2 percent surface coating to abrasive particle weight may be used. Such surface coatings are described in U.S. Pat. No. 5,213,591 (Celikkaya et al.); U.S. Pat. No. 5,011,508 (Wald et al.); U.S. Pat. No. 1,910,444 (Nicholson); U.S. Pat. No. 3,041,156 (Rowse et al.); U.S. Pat. No. 5,009,675 (Kunz et al.); U.S. Pat. No. 5,085,671 (Martin et al.); U.S. Pat. No. 4,997,461 (Markhoff-Matheny et al.); and U.S. Pat. No. 5,042,991 (Kunz et al.). Additionally, the surface coating may prevent the shaped abrasive particle from capping. Capping is the term to describe the phenomenon where metal particles from the workpiece being abraded become welded to the tops of the crushed abrasive particles. Surface coatings to perform the above functions are known to those of skill in the art.

Crushed abrasive particles used in practice of the present disclosure are preferably selected to have a length and/or width in a range of from 0.1 micron to 3500 microns, more typically 100 microns to 3000 microns, and more typically 100 microns to 2600 microns, although other lengths and widths may also be used.

Crushed abrasive particles may be selected to have a thickness in a range of from 0.1 micron to 1600 microns, more typically from 1 micron to 1200 microns, although other thicknesses may be used. In some embodiments, platey crushed abrasive particles may have an aspect ratio (length to thickness) of at least 2, 3, 4, 5, 6, or more.

Length, width, and thickness of the abrasive particles can be determined on an individual or average basis, as desired. Suitable techniques may include inspection and measurement of individual particles, as well as using automated image analysis techniques (e.g., using a dynamic image analyzer such as a CAMSIZER XT image analyzer from Retsch Technology Gmbh of Haan, Germany) according to test method ISO 13402-2:2006 “Particle size analysis—Image analysis methods—Part 2: Dynamic image analysis methods”.

FIG. 5 illustrates a method of using a pattern coated abrasive article in accordance with embodiments described herein. FIG. 5 may be referred to in conjunction with abrasive article 600 of FIG. 6. As illustrated in FIG. 6, at least some shaped abrasive particles have an asymmetric profile when viewed from the side. This causes each abrasive particle 630 to have a cutting face. In some embodiments, as described for example in 62/924,956, filed Oct. 23, 2019, shaped abrasive particles are oriented such that cutting faces of at least some abrasive particles 630 are aligned, and such that a cutting tip is oriented away from the backing. Abrasive particles 630 may be embedded within a make coat 620 such that particles 630 are aligned perpendicularly to backing 610, or such that a rake angle 660 is present. A size coat 640 may also be present.

Method 500 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.

Examples of 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.

In block 510, an abrasive article is provided. In one embodiment, the abrasive article includes a plurality of abrasive particles that are designed with a first direction of use and a second direction of use. For example, referring to FIG. 6, moving an abrasive article in a first direction of use refers to moving an abrasive article in direction 650, such that cutting faces 630 encounters a workpiece first. A second direction of use refers to moving an abrasive article in direction 660. According to various embodiments, a method of using an abrasive article such as abrasive belt or abrasive disc includes contacting shaped abrasive particles with a workpiece or substrate.

According to various embodiments, a cutting depth into the substrate or workpiece can be at least about 10 μm, at least about 20 μm, at least about 30 μm, at least about 40 μm, at least about 50 μm, or at least about 60 μm. A portion of the substrate or workpiece is removed by the abrasive article as a swarf.

In block 520, the abrasive article is moved against a workpiece in a first direction as indicated as indicated as direction 650 in FIG. 6, for example.

According to various embodiments, 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, 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.

For example, 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%. In some embodiments, 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%, 380%, 385%, 390%, 395%, 400%, 405%, 410%, 415%, 420%, 425%, 430%, 435%, 440%, 445%, 450%, 455%, 460%, 465%, 470%, 475%, 480%, 485%, 490%, 495%, or about 500%. The amount of material removed can be in reference to an initial cut (e.g., the first cut of a cutting cycle) or a total cut (e.g., a sum of the amount of material removed over a set number of cutting cycles).

As a further example, 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%. In some embodiments, 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%, 385%, 390%, 395%, 400%, 405%, 410%, 415%, 420%, 425%, 430%, 435%, 440%, 445%, 450%, 455%, 460%, 465%, 470%, 475%, 480%, 485%, 490%, 495%, or about 500%.

As a further example an arithmetical mean roughness value (Sa) of the workpiece or substrate cut by moving the abrasive article in first direction of use can be higher than a corresponding substrate or workpiece cut under the exact same conditions but in the second direction of movement. For example, 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.

Alternatively, as illustrated in block 530, it is possible for the abrasive article to be moved in a second direction 660 that is different than direction of use 650. While FIG. 6 illustrates a second direction 660 that is 180 degrees different from first direction 650, second direction 660 can be in a direction rotated about 1 degree to 360 degrees relative to direction of use 650, 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.

Although it may be desirable to move the abrasive article in first direction of use 650, there are some reasons to move the abrasive article in a second direction 660. For example, contacting the substrate or workpiece with the abrasive article and moving the abrasive article in second direction 660 may be beneficial for finishing the substrate or workpiece. While not intending to be bound to any particular theory, the inventors hypothesize that movement in the second direction may expose the substrate or workpiece to an angle other than a rake angle of the abrasive particle, which is more suited for finishing applications.

Coated abrasive articles made according to the methods of present disclosure are useful, for example, for abrading a workpiece. Examples of workpiece materials include metal, metal alloys, 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. The applied force during abrading typically ranges from about 1 kilogram to about 100 kilograms.

Coated abrasive articles made according to the methods of present disclosure may be used by hand and/or used in combination with a machine. At least one of the coated abrasive article and the workpiece is moved relative to the other when abrading. Abrading may be conducted under wet or dry conditions. Exemplary liquids for wet abrading include water, water containing conventional rust inhibiting compounds, lubricant, oil, soap, and cutting fluid. The liquid may also contain defoamers, degreasers, for example.

All cited references, patents, and patent applications in this application that are incorporated by reference, are incorporated in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the this application shall control. The preceding description, given in order to enable one of ordinary skill in the art to practice the claimed disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereto.

A coated abrasive article is presented. The coated abrasive article includes a backing having first and second opposed major surfaces. The coated abrasive article includes a make layer bonded to the first major surface. The coated abrasive article also includes abrasive particles directly bonded to the make layer. The abrasive particles are at least partially embedded in the make layer. The coated abrasive article also includes a size layer directly bonded to the make layer, and abrasive particles. One of the make layer and size layer comprise a patterned coating.

The article may be implemented such that the patterned coating comprises any of lines, swirls, polygonal shapes, letters, or numbers.

The article may be implemented such that the make layer comprises the patterned coating, and wherein the size layer comprises an even coating such that, for a portion of the backing, the size layer directly contacts the backing.

The article may be implemented such that both the make layer and size layer comprise the patterned coating.

The article may be implemented such that the size layer comprises the patterned coating, and wherein the coated abrasive article comprises a first color and a second color, and wherein the first color is a size layer color.

The article may also include a supersize coating.

The article may be implemented such that the supersize coating comprises a supersize pattern.

The article may be implemented such that the make layer comprises a cured resin.

The article may be implemented such that the size layer comprises a cured resin.

The article may be implemented such that the backing comprises a polymeric film, a metal foil, a woven fabric, a knitted fabric, paper, vulcanized fiber, a nonwoven, a foam, a screen, a mesh, or a combination thereof.

The article may be implemented such that it also includes a laminate coated directly to the first major surface of the backing, and wherein the make layer is bonded to the laminate.

The article may be implemented such that the backing is pretreated with a backsize, a presize, or a saturant.

The article may be implemented such that the abrasive particles are shaped abrasive particles.

The article may be implemented such that at least some of the shaped abrasive particles are aligned with respect to each other.

The article may be implemented such that at least some of the shaped abrasive particles are aligned such that a cutting face of each of the shaped abrasive particles are aligned and such that a base of each of the shaped abrasive particles is embedded within the make layer.

The article may be implemented such that the abrasive particles are magnetically coated.

The article may be implemented such that the patterned coating comprises a repeating unit.

The article may be implemented such that the patterned coating extends from a center of the abrasive article to an edge of the abrasive article.

The article may be implemented such that the abrasive article is an abrasive disc or an abrasive belt.

A method of making a coated abrasive article. The method includes depositing a curable make layer precursor on a major surface of a backing. The method also includes depositing a plurality of abrasive particles onto the curable make layer precursor. The method also includes at least partially curing the curable make layer precursor. The method also includes depositing a curable size layer precursor on the plurality of abrasive particles. The method also includes at least partially curing the curable size layer precursor. One of the curable make layer precursor and the curable size layer are deposited in a pattern on the major surface of the backing.

The method may be implemented such that the pattern comprises a repeating unit.

The method may be implemented such that the pattern comprises a line, a swirl, a polygonal shape, a letter, or a number.

The method may be implemented such that the pattern comprises a first color and a second color.

The method may be implemented such that the first color is a color of a cured size layer.

The method may be implemented such that the method also comprises depositing a supersize layer.

The method may be implemented such that the supersize layer is deposited in a supersize pattern, and wherein the second color comprises a supersize color.

The method may be implemented such that the plurality of abrasive particles are deposited such that only a first portion of each abrasive particle embeds within the curable make layer precursor, and a second portion of each abrasive particle is free of make layer precursor.

The method may be implemented such that the backing comprises a polymeric film, a metal foil, a woven fabric, a knitted fabric, paper, vulcanized fiber, a nonwoven, a foam, a screen, a mesh, or a combination thereof.

The method may also include depositing a laminate coated directly to the first major surface of the backing, and wherein the make layer bonds to the laminate.

The method may also include pretreating the backing with a backsize, a presize, or a saturant.

The method may be implemented such that the abrasive particles are deposited in a particle pattern.

The method may be implemented such that the particle pattern differs from the pattern.

The method may be implemented such that the abrasive particles comprise crushed, platey, formed or shaped abrasive particles.

The method may be implemented such that the abrasive particles are shaped abrasive particles, and wherein each of the shaped abrasive particles comprise at least one polygonal face.

The method may be implemented such that each of the shaped abrasive particles comprise at least one asymmetric face.

The method may be implemented such that the abrasive particles are magnetically coated.

The method may be implemented such that the abrasive particles are aligned on the backing such that the at least one polygonal face of some of the shaped abrasive particles are aligned with respect to each other.

The method may be implemented such that the at least one polygonal face of some of the shaped abrasive particles are aligned with respect to the backing.

The method may be implemented such that the abrasive particles are angled with respect to the backing.

Examples

Unless otherwise noted, all parts, percentages, ratios, etc. in the Examples and the rest of the specification are by weight.

Unless stated otherwise, all other reagents were obtained, or are available from fine chemical vendors such as Sigma-Aldrich Company, St. Louis, Mo., or may be synthesized by known methods.

Unit Abbreviations used in the Examples:

° C.: degrees Centigrade

Ø: Diameter

cm: centimeter

in: inch

g: gram

g/m²: grams per square meter

rpm: revolutions per minute

mm: millimeter

wt. %: weight percent

Acronym      Description
PR1          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.
CACO         Calcium Carbonate commercially available as HUBERCARB Q325 from
             Hubercarb Engineered Materials, Atlanta Georgia.
CRY          Cryolite, obtained as CRYOLITE RTN-C from Freebee A/S, Ullerslev,
             Denmark.
IO           Red iron oxide pigment, obtained as KROMA RO-3097 from Elementis
             Specialties, Inc., East Saint Louis, Illinois.
Make Resin 1 A phenolic curable make resin prepared by mixing 49.2 parts by weight
             of PR1; 40.6 parts by weight of CACO; and 10.2 parts by weight of
             deionized water.
Size Resin 1 A phenolic curable size resin prepared by mixing 40.6 parts by weight of
             PR1; 69.9 parts by weight of CRY; 2.5 parts by weight IO; and 25 parts
             by weight deionized water.
EC 1428      Zinc stearate dispersion in water with additives supplied by eChem
             Limited, Leeds, UK.
CMC          Carboxymethylcellulose sodium salt, obtained from Alfa Aesar,
             Haverhill, MA.
Anti-load    A mix of water, CMC, and EC 1428 by the weight ratio of 19.5:0.5:80.
NET MESH     Net Mesh GR150 H100 available from SitiP, S.p.A., Cene, Italy.
BCA          Black silicon carbide abrasive grits, P180 grade, supplied by GNP
             CERAMICS, LLC, NY
FRPL P220    P220 grade Semi-friable fused aluminum oxide abrasive mineral,
             obtained from Imerys, Paris, France.

Procedure of Making Mesh Abrasives

Mesh backing was cut into small discs with 6-inch diameters or 3.5-inch diameters before use.

Even make coating was achieved by applying 2.36 g make resin onto the 6-inch Ø mesh backing with a 3M hand rubber roller or applying 1.32 g make resin onto the 3.5-inch Ø mesh backing.

Pattern make coating was achieved by applying make resin onto the mesh backing through a patterned stencil described in U.S. Provisional Applications 62/945,242 filed on Dec. 9, 2019. with 3M hand rubber roller.

Mineral drop coating was achieved by spread abrasive mineral grits onto the make resin layer.

Curing process: the mesh abrasive sample was pre-cured at 90° C. for 2 hrs and then cured at 102° C. for at least 6 hrs.

FIG. 7A illustrates a 3.5-inch Ø mesh backing. and FIG. 7B illustrates a 3.5-inch Ø mesh backing with pattern make and mineral coating. FIG. 7C illustrates a 3.5-inch Ø mesh abrasive with patterned make, mineral and size coating.

FIG. 7D illustrates a 3.5-inch Ø mesh backing with an even make coat and even mineral coat. FIG. 7E illustrates a 3.5-inch Ø mesh abrasive with an even make coat, even mineral coat and patterned size coat. FIG. 7F illustrates a 3.5-inch Ø mesh abrasive with a pattern make coating, pattern mineral coating and even size coating.

FIG. 7G illustrates a 3.5-inch Ø backing with an even make coat and patterned mineral coating of BCA and FRPL 220. FIG. 7H illustrates a close up view of the article of FIG. 7G.

FIG. 7I illustrates a 6-inch Ø mesh abrasive article with an even make coat, even mineral coat and patterned anti-load coating.

Claims

1. A coated abrasive article comprising:

a backing having first and second opposed major surfaces;

a make layer bonded to the first major surface;

abrasive particles directly bonded to the make layer, wherein the abrasive particles are at least partially embedded in the make layer;

a size layer directly bonded to the make layer, and abrasive particles; and

wherein one of the make layer and size layer comprise a patterned coating.

2. (canceled)

3. The article of claim 1, wherein the make layer comprises the patterned coating, and wherein the size layer comprises an even coating such that, for a portion of the backing, the size layer directly contacts the backing.

4. The article of claim 1, wherein both the make layer and size layer comprise the patterned coating.

5. The article of claim 1, wherein the size layer comprises the patterned coating, and wherein the coated abrasive article comprises a first color and a second color, and wherein the first color is a size layer color.

6. The article of claim 1, and further comprising a supersize coating and wherein the supersize coating comprises a supersize pattern.

7-10. (canceled)

11. The abrasive article of claim 1, and further comprising a laminate coated directly to the first major surface of the backing, and wherein the make layer is bonded to the laminate.

12. The abrasive article of claim 1, wherein the backing is pretreated with a backsize, a presize, or a saturant.

13-16. (canceled)

17. The abrasive article of claim 1, wherein the patterned coating comprises a repeating unit.

18. The abrasive article of claim 1, wherein the patterned coating extends from a center of the abrasive article to an edge of the abrasive article.

19. (canceled)

20. A method of making a coated abrasive article, the method comprising sequentially:

depositing a curable make layer precursor on a major surface of a backing;

depositing a plurality of abrasive particles onto the curable make layer precursor;

at least partially curing the curable make layer precursor;

depositing a curable size layer precursor on the plurality of abrasive particles; and

at least partially curing the curable size layer precursor; and

wherein one of the curable make layer precursor and the curable size layer are deposited in a pattern on the major surface of the backing.

21. The method of claim 20, wherein the pattern comprises a repeating unit.

22. (canceled)

23. The method of claim 20, wherein the pattern comprises a first color and a second color.

24. The method of claim 23, wherein the first color is a color of a cured size layer.

25. The method of claim 23, wherein the method also comprises depositing a supersize layer and, wherein the supersize layer is deposited in a supersize pattern, and wherein the second color comprises a supersize color.

26. (canceled)

27. The method of claim 20, wherein the plurality of abrasive particles are deposited such that only a first portion of each abrasive particle embeds within the curable make layer precursor, and a second portion of each abrasive particle is free of make layer precursor.

28. (canceled)

29. The method of claim 20, and further comprising depositing a laminate coated directly to the first major surface of the backing, and wherein the make layer bonds to the laminate.

30. (canceled)

31. The method of claim 20, wherein the abrasive particles are deposited in a particle and, wherein the particle pattern differs from the pattern.

32. (canceled)

33. (canceled)

34. The method of claim 33, wherein the abrasive particles are shaped abrasive particles, and wherein each of the shaped abrasive particles comprise at least one polygonal face.

35. The method of claim 34, wherein each of the shaped abrasive particles comprise at least one asymmetric face.

36. (canceled)

37. The method of claim 34, wherein the abrasive particles are aligned on the backing such that the at least one polygonal face of some of the shaped abrasive particles are aligned with respect to each other.

38. (canceled)

39. (canceled)