Abrasive article

Abstract

An abrasive article that includes a backing having a first major side opposite a second major side. The abrasive article also includes a primer layer directly coupled to the first major side of the backing. The abrasive article also includes a plurality of abrasive particles coupled directly to the primer layer. The abrasive article also includes a coating layer applied over the plurality of abrasive particles.

Description

PA101628W002ABRASIVE ARTICLEBACKGROUND

[0001] Abrasive articles generally comprise abrasive particles (also known as "grains") retained within a binder. During manufacture of various types of abrasive articles, the abrasive particles are deposited on a binder material precursor in an oriented manner (e.g., by electrostatic coating or by some mechanical placement technique). Typically, the most desirable orientation of the abrasive particles is substantially perpendicular to the surface of the backing.

[0002] In the case of certain coated abrasive articles (e.g., grinding discs), a make layer precursor (or make coat) containing a first binder material precursor is applied to a backing material, and then abrasive particles are partially embedded into the make layer precursor. Frequently, the abrasive particles are embedded in the make layer precursor with a degree of orientation; e.g., by electrostatic coating or by a mechanical placement technique. Size and or supersize coats may be applied over the abrasive particles.BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0004] FIG. 1 is a schematic view showing the configuration of a super finishing apparatus in which embodiments herein may be useful.

[0005] FIG. 2 is a cross-sectional side view of a traditional coated abrasive article.

[0006] FIG. 3 illustrates a coated abrasive article in accordance with embodiments herein.

[0007] FIG. 4 illustrates a method of forming a coated abrasive article in accordance with embodiments herein.

[0008] FIGS. 5A-5H illustrate example patterns for pattern coated abrasive particles in accordance with embodiments herein.

[0009] FIGS. 6-7 illustrate abrasive articles described in greater detail in the Examples.

[0010] It should be understood that numerous other modifications and examples can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. Figures may not be drawn to scale.DESCRIPTION

[0011] In general, coated abrasive articles have abrasive particles secured to a backing. Coated abrasive articles can include a backing having two major opposed surfaces and an abrasive layer secured to one of the major surfaces. The abrasive layer typically includes abrasive particles and a binding layer for securing the abrasive particles to the backing.

[0012] ‘ ‘Orientation” refers to a desired alignment of an abrasive particle on a surface. “% orientation” refers to a percentage of abrasive particles that are properly aligned on the backing material after curing;

[0013] “properly oriented abrasive particles” refer to abrasive particles that are + / - X% of a desired orientation angle with respect to a backing.

[0014] "weight percent" and "percent by weight" are interchangeable.

[0015] The term "length" refers to the maximum extent of an object along its greatest dimension.

[0016] The term "width" refers to the maximum extent of something along a dimension orthogonal to the length.

[0017] The term "thickness" refers to the maximum extent of something along a dimension orthogonal to both the length and the width.

[0018] Embodiments herein describe abrasive articles that may used in a number of applications. However, one area where embodiments herein may be particularly useful in micro-finishing applications. Micro finishing film (MFF) is an area of abrasive article manufacture where users are looking for increasing performance. Embodiments herein may be particularly useful for MFF applications. Embodiments herein differ from conventional coated abrasive articles in that abrasive particles are secured directly to a primed backing, without the presence of a phenolic make resin.

[0019] Some embodiments herein utilize polyethylene terephthalate (PET) film as a backing material. Traditional phenolic resins, often used as make coats to adhere / secure abrasive particles to the backing, do not bond well to plain, untreated polyester or PET films. Priming the backing, and replacing the make coat layer altogether result in lower manufacturing cost with similar or improved cut performance.

[0020] Additionally, the use of primers described herein also allow for the pattern coating of abrasive particles by, for example, flexographic printing of a UV ink pattern on theprimed film. The areas of the backing where UV ink is printed are free of abrasive particles in the final construction.

[0021] However, it is expressly contemplated that, while embodiments herein are discussed in the context of micro finishing applications, the same or similar embodiments may be useful for other applications as well.

[0022] FIG. 1 is a schematic view showing the configuration of a super finishing apparatus in which embodiments herein may be useful. An abrasive material product 11 is fed out of a feeding roll 12 and wound up on a rolling roll 14 via a contact roll 13. The contact roll is pushed to the outer circumferential face of the cylindrical work piece 16 by an air cylinder 15. While the cylindrical work piece 16 is rotated in the direction of the arrow, the abrasive material product is fed to the direction opposed to the direction of movement of the object face to be abraded to carry out abrading. However, while FIG. 1 illustrates one example of a super finishing apparatus, it is expressly contemplated that other machine arrangements may be used.

[0023] Contact-wheel based sanding systems present an alternative to sanding disc systems, as they can be used in a role-to-role system and allow for a long abrasive life. Contactwheel based systems have a small contact area which can result in an applied unit pressure become too high a pressure for a given operation. As more and more sanding and finishing operations are moving to robotic solutions, it is required that a system be compliant for surfaces that have curvature.

[0024] The abrasive articles described herein may be used in either a continuous feed or an intermittent feed method. In a continuous feed setup, dynamic friction is created. Therefore, the system may result in lower polishing performance and / or require equipment with stronger feeding power.

[0025] FIG. 2 is a cross-sectional side view of a traditional coated abrasive article. Coated abrasive article 100 has backing 120 and abrasive layer 130. Abrasive layer 130 includes abrasive particles 140 secured to major surface 170 of backing 120 (substrate) by make layer 150 and size layer 160.

[0026] Coated abrasive articles often include additional layers such as, for example, an optional supersize layer 180 that is superimposed on the abrasive layer, or a backing antistatic treatment layer may also be included.

[0027] Shaped abrasive particles are often designed to have a tip or an edge configured to engage worksurface - e.g. abrasive particles 140 illustrated in FIG. 2 have cutting tips and edges. If, however, the abrasive particles are not oriented correctly, the cutting efficacy can be significantly reduced.

[0028] FIG. 3 illustrates a coated abrasive article in accordance with embodiments herein. Coated abrasive article 200 has a backing 210. Backing 210 may be any suitable backing, such as a film, a cloth, or paper.

[0029] A primer layer 220 has been applied to backing 210. A plurality of abrasive particles 230 are embedded in primer layer 220. Primer layer 220 secures abrasive particles 230 to backing 210. Abrasive particles 230 may be coated on primer layer 220 in any suitable manner including electrostatic coating, pattern coating, or another suitable process.

[0030] Abrasive particles 230 are directly coupled to primer layer 220, in some embodiments herein. During formation of the abrasive article 200, abrasive particles 200 are coated directly onto primer layer 220. In some embodiments herein, primer layer 220 is an ethylene / acrylic acid (EAA) primer layer. In some embodiments herein, primer layer 220 is a polyethylene layer. In some embodiments herein, primer layer 220 is a thermoplastic polyurethane layer, primer layer 220 is ethylene-vinyl acetate. However, it is expressly contemplated that other suitable thermoplastics could be used.

[0031] In some embodiments, as in traditional coated abrasive articles, one or more additional layers 240 are coated over the deposited abrasive particles. For example, in contrast to conventional coated abrasive articles, in embodiments herein a make coat may be applied over the abrasive particles 230. For example, a phenolic resin layer 240 may be applied over abrasive particles 230 and primer layer 220, in some embodiments. In some embodiments a hot melt layer 240, for example formed of, may be applied over abrasive particles 230 and primer layer 220. Size layer 240 may also be formed of other suitable materials, for example thermal epoxy, a UV-cured epoxy resin, a UV epoxy / acrylate, or a urea-formaldehyde .

[0032] In some embodiments, a size layer 240 is applied over abrasive particles 230 and primer layer 220 instead of, or in addition to, a make layer. Size layer 240 may be a UV curable epoxy resin layer or a phenolic resin layer.

[0033] In some embodiments, a backsize layer 250 is present. As used here, a backsize layer 250 is a coating on the major surface of the backing opposite the major surface havingthe abrasive layer. In some embodiments, the backsize includes filler particles in a polymeric carrier. The polymeric carrier may be any suitable polymer, such as a thermoset epoxy, a polyurethane, a phenolic resun, a urea formaldehyde, a melamine formaldehyde, etc. The backsize can be applied before or after a primer layer as described herein. In some embodiments, the backsize layer provides friction during use.

[0034] The filler particles may include any suitable non-functional particle that can provide friction. For example, the filler particles may include any of: 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; quartz; vermiculite; wood flour; aluminum trihydrate; metal oxides, such as calcium oxide (lime), aluminum oxide, titanium dioxide, and metal sulfites, such as calcium sulfite.

[0035] Additional layers may also be present, such as a supersize layer (not shown in FIG. 3).

[0036] The abrasive particles 230 are at least partially embedded in the primer layer 220. As used herein, the term “at least partially embedded” generally means that at least a portion of an abrasive particle is embedded in the primer layer 220, such that, the abrasive particle is anchored in the primer layer 220? In such embodiments, abrasive particles 230 can optionally be oriented by influence of a magnetic field prior to the primer layer 220 being cured. See, for example, U.S. Pat. Pub. Nos. 2018 / 080703, 2018 / 080756, 2018 / 080704, 2018 / 080705, 2018 / 080765, 2018 / 080784, 2018 / 136271, 2018 / 134732, 2018 / 080755, 2018 / 080799, 2018 / 136269, 2018 / 136268.

[0037] FIG. 3 illustrates an embodiment where abrasive particles 230 are pattern-coated, with areas of primer layer 220 being free of abrasive particles 230 before layer 240 is applied. In some embodiments herein a mask is used to limit where abrasive particles are coated on, and embedded into, primer layer 220. The mask may be a physical mask, in some embodiments. In other embodiments pattern coating is achieved by applying a mask to the primer layer 220 prior to deposition of abrasive particles 230. For example, in someembodiments a printable ink is provided over primer layer 220, covering areas where abrasive particles 230 are not desired. In some embodiments the ink is a UV-curable ink.

[0038] Other suitable pattern coating mechanisms are also envisioned.

[0039] FIG. 4 illustrates a method of forming a coated abrasive article in accordance with embodiments herein. Method 400 may be useful, for example, for forming an abrasive article 200.

[0040] At block 410, a backing material is prepared. A suitable backing substrate may be constructed from any of a number of materials known in the art for making coated abrasive articles. For example, backing substrate can be any of fabric, open-weave cloth, knitted fabric, porous cloth, loop materials, unsealed fabrics, open or closed cell foams, a nonwoven fabric, a spun fiber, a film, a perforated film or any other suitable backing material. A fabric backing may include cloth (e.g., cloth made from fibers or yams comprising polyester, nylon, silk, cotton, and / or rayon, which may be woven, knit or stitch bonded) or scrim. Many of these materials can have an uneven or rough surface. Applying a laminate to a backing material prior to applying a make coat can create a more continuous, flatter and smoother surface for abrasive coating than would be available without a laminate.

[0041] Abrasive articles according to the present disclosure and / or made by the process of the present disclosure including a polyester backing. Useful polyester films may be manufactured from various types of thermoplastic polyester resins, including polyethylene terephthalate, polytetramethylene terephthalate, polyethylene-2, 6-naphthalate, and poly- 1,4-cyclohexylene dimethyl terephthalate. Polyester copolymers (e.g., polyethylene terephthalate / isophthalate, polyethylene terephthalate / adipate, polyethylene terephthalate / sebacate, polyethylene terephthalate / sulfoisophthalate, and polyethylene terephthalate / azelate) may also be useful.

[0042] For abrasive articles the polyester backing can be a fdm backing. In addition to the dense, monolithic fdm backing, fibrous backings are also useful in the abrasive articles described herein. In some embodiments, the polyester backing is a nonwoven. Nonwoven abrasive articles, such as a spunbound backing, typically include an open porous lofty polymer filament structure having abrasive particles distributed throughout the structure and adherently bonded therein by an organic binder, in some embodiments, a phenolic resin as described above in any of its embodiments. Examples of filaments include polyester fibersmade from any of the polyesters described above in connection with the polyester fdm backing.

[0043] Polyester fdm backings useful for practicing some aspects of the present disclosure can have a variety of thicknesses. In some embodiments, the thickness of the polyester fdm backing is in a range from 1 micrometer to 500 micrometers, 10 micrometers to 350 micrometers, 25 micrometers to 250 micrometers, or 35 micrometers to 200 micrometers.

[0044] In some embodiments herein, the backing material is a fdm that includes polyethylene terephthalate (PET). In some embodiments, the polyester fdm backing has a uniform composition throughout its thickness. In other embodiments, PET or any other suitable polyesters described above may be included in a layer of a multilayer fdm backing.

[0045] In polyester fdm backings useful for practicing some aspects the present disclosure, the fdm backing would be considered monolithic (that is, having a generally uniform fdm composition) and is not fibrous. Particularly, the fdm backing is not a nonwoven material. The polyester fdm backing can be described as a dense fdm and not an open, lofty, fibrous web.

[0046] The polyester film backing useful for practicing the present disclosure may be oriented, either uniaxially or biaxially . Orientation of a film at a temperature above its glass transition temperature can be useful for enhancing at least one of the stiffness, modulus, or creep resistance of the film. Orientation can conveniently be carried out by conventional methods such as mechanical stretching (drawing) or tubular expansion with heated air or gas. Examples of useful draw ratios are in the range of 2.5 to 6 times in the machine, crossmachine direction, or both the machine and cross-machine directions. Larger draw ratios (for example, up to about 8 times) may also be useful if the film is oriented in only one direction. For biaxially oriented film backings, the film may be stretched equally in the machine and cross-machine directions or unequally in the machine and cross-machine directions.

[0047] Preparing a backing may include any suitable treatment of the backing. Some examples of typical backing treatments are a backsize layer (that is, a coating on the major surface of the backing opposite the abrasive layer), a presize layer or a tie layer (that is, a coating on the backing disposed between the abrasive layer and the backing), and / or a saturant that saturates the backing. A subsize is similar to a saturant, except that it is applied to a previously treated backing.

[0048] The purpose of optional backing treatments (that is, saturant, pre size layer, backsize layer) is typically to seal the backing and / or promote adhesion of other layer(s) to the backing. Typically, at least one of these backing treatments is used, although this is not a requirement. Materials useful as backing treatments include, for example, phenolics resins (especially, resole resins), epoxy resins, acrylate resins, acrylic latexes, urethane resins, aminoplasts, glue, starch, and combinations thereof. Additional materials useful as backing treatments include, for example, those described in U.S. Pat. Appl. Publ. Nos. 2005 / 0100739 Al (Thurber et al); 2004 / 0002951 Al (Kincaid et al); and 2005 / 0282029 Al, (Keipert et al.); and U.S. Pat. Nos. 5,108,463 (Buchanan et al.); 5,137,542 (Buchanan et al.); 5,328,716 (Buchanan); 5,560,753 (Buchanan et al.); 6,372,336 Bl (Clausen et al.); 6,936,083 B2 (Thurber et al.); 7,344,574 B2 (Thurber et al.); and 7,344,575 B2 (Thurber et al.).

[0049] The inclusion of a presize layer or backsize layer may additionally result in a "smoother" surface on either the front and / or the backside of the backing. Materials useful as backing treatments include, for example, phenolics resins.

[0050] Coating of a backing treatment composition can be performed in a variety of ways including brushing, spraying, roll coating, curtain coating, gravure coating, and knife coating. The coated backing may then be processed for a time at a temperature sufficient to dry and at least partially crosslink the coating to form the treatment layer on the backing.

[0051] In some embodiments, a backing material undergoes a surface treatment. Useful surface treatments include electrical discharge in the presence of a suitable reactive or non- reactive atmosphere (e.g., plasma, glow discharge, corona discharge, dielectric barrier discharge or atmospheric pressure discharge); ultraviolet light exposure, electron beam exposure, flame discharge, and scuffing. The surface treatment can be applied as the polyester film backing is being made or in a separate process. In some embodiments, the polyester film backing is surface-treated using corona discharge. An example of a useful corona discharge process is described in U.S. Pat. No. 5,972,176 (Kirk et al.).

[0052] At block 420, a primer layer is applied. A primer layer is applied, in embodiments herein, directly to the (treated or untreated) backing layer. In embodiments herein, the primer layer is applied as curable polymeric compound. The primer layer, in some embodiments herein, includes an ethylene / acrylic acid polymer precursor. In someembodiments, the primer layer includes a polyurethane precursor. In some embodiments, the primer layer includes a polyethylene precursor.

[0053] Some examples of primer treatments are described in co-owned pending PCT application IB2019 / 056300, fried on July 23, 2019, which claims priority to US Provisional 62 / 702029, filed on July 23, 2018, which is herein incorporated by reference. However, in contrast to the primer treatments of the noted application, primers in embodiments herein, are applied as a hot melt. Primers herein include thermoplastic resins that at least partially melt when heated, allowing for them to be coated on a surface, such as a film backing such as, for example, ethyl -vinyl acetate (EVA, ethyl acrylic acid (EAA). In some embodiments, a second primer layer is applied to a backing prior to the hot melt primer. In some embodiments herein, the thermoplastic primer layer is applied as a continuous primer layer substantially free of gaps or holes.

[0054] The primer layer can include one or more additives, if desired. In some embodiments, the primer layer includes at least one of an organic solvent, a surfactant, an emulsifier, a dispersant, a catalyst, a rheology modifier, a density modifier, a cure modifier, a diluent, an antioxidant, a heat stabilizer, a flame retardant, a plasticizer, filler, a polishing aid, a pigment, a dye, an adhesion promoter, antistatic additives. In various embodiments, the presence or lack of certain of these additives can reduce cost, control viscosity, or improve physical properties. In some embodiments, the primer layer comprises a surfactant. Such additives may be homogeneous or heterogeneous with one or more components in the composition. Heterogenous additives may be discrete (e.g., particulate) or continuous in nature.

[0055] Aforementioned additives can include, for example, surfactants (e.g., antifoaming agents such as ethoxylated nonionic surfactants such as DYNOL 604), pigments (e.g., carbon black pigment such as C-SERIES BLACK 7 LCD4115), fillers (e.g. silicon dioxide Cabosil M5), synthetic waxes (e.g., synthetic paraffin MP22), stabilizers, plasticizers, tackifiers, flow control agents, cure rate retarders, adhesion promoters (for example, silanes such as (3-glycidoxypropyl)trimethoxysilane (GPTMS), and titanates), adjuvants, impact modifiers, expandable microspheres, thermally conductive particles, electrically conductive particles, and the like, such as silica, glass, clay, talc, colorants, glass beads or bubbles, and antioxidants, so as to, e.g., reduce the weight and / or cost of the structural layer composition, adjust viscosity, and / or provide additional reinforcement or modify the thermal conductivityof compositions and articles used in the provided methods or so that a more rapid or uniform cure may be achieved.

[0056] In some embodiments herein, the primer layer is a thin primer layer, having a thickness of less than 1 mm, or even less than 0.8 mm, or even less than 0.6 mm, or even less than 0.4 mm, or even less than 0.3 mm.

[0057] At block 430, in embodiments where abrasive particles are pattern coated onto the primer layer, a masking agent is applied. Applying a masking layer, in some embodiments, includes application or placement of a physical mask, which is removed after the abrasive particles are deposited onto the primer layer. The physical mask may be placed above, but not in contact with, the primer layer in some embodiments. In other embodiments, the physical mask is removably applied to the primer layer.

[0058] In some embodiments herein, the masking layer is a curable compound. The masking layer curable compound, in embodiments herein, cures through a different process than the primer layer such that, as described with respect to block 440, the masking layer curable compound is at least partially cured while the primer layer is sufficiently tacky such that abrasive particles can embed therein. In some embodiments, the masking layer includes a UV-curable ink that is printed onto the surface of the primer layer. A number of UV- curable inks are available that would be suitable for embodiments herein. For example, a large variety of UV curable inks are available from Nazdar Ink Technologies under there 9300 Series UV Flexo Ink.

[0059] At block 440, in embodiments where a curable masking agent is used, the curable masking agent is at least partially cured. In some embodiments herein, two curable compounds are applied to the backing - a curable primer layer compounds and a masking compound. The curable primer layer compound needs to be sufficiently tacky that abrasive particles, when applied in block 440, will embed into or stick thereto. At block 440, curing of the curable masking agent is at least initiated.

[0060] In some embodiments, curing of the curable masking agent is initiated using a photo initiator and exposure to light in the UV or IR spectrum. In some embodiments, curing of the curable masking agent is initiated using heat. In some embodiments, the curable masking agent includes a catalyst such that curing proceeds automatically, such that the steps described in blocks 430 and 440 happen in parallel.

[0061] At block 450, abrasive particles are applied. In embodiments herein, abrasive particles are applied directly to the at least partially uncured primer layer. In embodiments where a masking agent is used, the masking agent is sufficiently solid such that the portions of the primer layer where abrasive particles are not desired are not tacky enough for abrasive particles to embed, or are physically covered. For example, a curable masking agent may be cured or mostly cured when abrasive particles are applied in block 450.

[0062] A wide variety of abrasive particles may be used in the various embodiments described herein. The particular type of abrasive particle (e.g. size, shape, chemical composition) is not considered to be particularly significant to the abrasive article, so long as at least a portion of the abrasive particles are suitable for the intended end-use application. Suitable abrasive particles may be formed of, for example, cubic boron nitride, zirconia, alumina, silicon carbide and diamond.

[0063] The abrasive particles may be provided in a variety of sizes, shapes and profiles, including, for example, random or crushed shapes, regular (e.g. symmetric) profiles such as square, star-shaped or hexagonal profiles, and irregular (e.g. asymmetric) profiles.

[0064] The abrasive article may include a mixture of abrasive particles that are inclined on the backing (i.e. stand upright and extend outwardly from the backing) as well as abrasive particles that lie flat on their side (i.e. they do not stand upright and extend outwardly from the backing).

[0065] The abrasive article may include a mixture of different types of abrasive particles. For example, the abrasive article may include mixtures of platey and non-platey particles, crushed, agglomerated, and shaped particles (which may be discrete abrasive particles that do not contain a binder or agglomerate abrasive particles that contain a binder), conventional non-shaped and non-platey abrasive particles (e.g. filler material) and abrasive particles of different sizes.

[0066] Examples of suitable shaped abrasive particles can be found in, for example, U.S. Patent Nos. 5,201,916 (Berg) and 8,142,531 (Adefris et al.) A material from which the shaped abrasive particles may be formed comprises alpha alumina. Alpha alumina shaped abrasive particles can be made from a dispersion of aluminum oxide monohydrate that is gelled, molded to shape, dried to retain the shape, calcined, and sintered according to techniques known in the art.

[0067] As used herein, the term “shaped abrasive particle,” generally refers to abrasive particles with at least a portion of the abrasive particles 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 U.S. patent publication US 2009 / 0169816), 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 randomly sized abrasive particles obtained by a mechanical crushing operation.

[0068] Examples of suitable shaped abrasive particles can also be found in Published U.S. Appl. No. 2015 / 0267097, which is incorporated herein by reference. Published U.S. Appl. No. 2015 / 0267097 generally describes abrasive particles comprising alpha alumina having an average crystal grain size of 0.8 to 8 microns and an apparent density that is at least 92 percent of the true density. Each shaped abrasive particle can have a respective surface comprising a plurality of smooth sides that form at least four vertexes.

[0069] U.S. Patent No. 8,034,137 (Erickson et al.) describes alumina 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 shaped abrasive particles and methods for their preparation can be found, for example, in U.S. Patent Nos. 8,142,531 (Adefris et al.); 8,142,891 (Culler et al.); and 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).

[0070] Examples of suitable crushed 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, Minnesota, brown aluminum oxide, blue aluminum oxide, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina zirconia, iron oxide, chromia, zirconia, titania, tin oxide, quartz, feldspar, flint, emery, sol-gel-derived ceramic (e.g., alpha alumina), and combinations thereof. Further examples include crushed abrasive composites of abrasive particles (whichmay be platey or not) in a binder matrix, such as those described in U.S. Patent No. 5,152,917 (Pieper et al.).

[0071] Examples of sol-gel-derived abrasive particles from which crushed abrasive particles can be isolated, and methods fortheir preparation can be found in U.S. Patent 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.). It is also contemplated that the crushed abrasive particles could comprise abrasive agglomerates such as, for example, those described in U.S. Patent Nos. 4,652,275 (Bloecher et al.) or 4,799,939 (Bloecher et al.).

[0072] The 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. Patent No. 5,213,591 (Celikkaya et al.) and U.S. Publ. Pat. Appln. Nos. 2009 / 0165394 Al (Culler et al.) and 2009 / 0169816 Al (Erickson et al.).

[0073] Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Patent Nos. 4,314,827 (Leitheiser); 5,152,917 (Pieper et al.); 5,435,816 (Spurgeon et al.); 5,672,097 (Hoopman et al.); 5,946,991 (Hoopman et al.); 5,975,987 (Hoopman et al.); and 6, 129,540 (Hoopman et al.); and in U.S. Patent Publication No. 2009 / 0165394 Al (Culler et al.). Examples of suitable platey crushed abrasive particles can be found in, for example, U.S. Patent No. 4,848,041 (Kruschke).

[0074] The 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 the binder.

[0075] The abrasive layer, in some embodiments, includes a particulate mixture comprising a plurality of formed abrasive particles (e.g., precision shaped grain (PSG) mineral particles available from 3M, St. Paul, MN) and a plurality of abrasive particles 450, or only formed abrasive particles, adhesively secured to the abrasive layer.

[0076] In some embodiment, the abrasive particles may be formed abrasive particles. As used herein, the term “formed abrasive particles” generally refers to abrasive particles (e.g., formed ceramic abrasive particles) having at least a partially replicated shape. Non-limiting examples of formed abrasive particles are disclosed in Published U.S. Patent Appl. No.2013 / 0344786, which is incorporated by reference as if fully set forth herein. Non-limiting examples of formed abrasive particles include shaped abrasive particles formed in a mold, such as triangular plates as disclosed in U.S. Pat. Nos. RE 35,570; 5,201,916, and 5,984,998 all of which are incorporated by reference as if fully set forth herein; or extruded elongated ceramic rods / fdaments often having a circular cross section produced by Saint-Gobain Abrasives an example of which is disclosed in U.S. Pat. No. 5,372,620, which is incorporated by reference as if fully set forth herein. Formed abrasive particle as used herein excludes randomly sized abrasive particles obtained by a mechanical crushing operation.

[0077] Formed abrasive particles also include shaped abrasive particles. Formed abrasive particles also include precision-shaped grain (PSG) mineral particles, such as those described in Published U.S. Appl. No. 2015 / 267097, which is incorporated by reference as if fully set forth herein.

[0078] Examples of suitable abrasive particles include, for example, fused aluminum oxide, heat treated aluminum oxide, white fused aluminum oxide, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, silicon nitride, tungsten carbide, titanium carbide, diamond, cubic boron nitride, hexagonal boron nitride, garnet, fused alumina zirconia, alumina-based sol gel derived abrasive particles, silica, iron oxide, chromia, ceria, zirconia, titania, tin oxide, gamma alumina, and mixtures thereof. The alumina abrasive particles may contain a metal oxide modifier. The diamond and cubic boron nitride abrasive particles may be monocrystalline or poly crystalline.

[0079] In some examples, the formed abrasive particles have a substantially monodisperse particle size of from about 1 micrometers to about 5000 micrometers, from about 1 micrometers to about 2500, from about 1 micrometers to about 1000, from about 10 micrometers to about 5000, from about 10 micrometers to about 2500, from about 10 micrometers to about 1000, from about 50 micrometers to about 5000, from about 50 micrometers to about 2500, from about 50 micrometers to about 1000. As used herein, the term “substantially monodisperse particle size” is used to describe formed abrasive particles having a size that does not vary substantially. Thus, for example, when referring to formed abrasive particles (e.g., a PSG mineral particles) having a particle size of 100 micrometers, greater than 90%, greater than 95% or greater than 99% of the formed abrasive particles will have a particle having its largest dimension be 100 micrometers.

[0080] In some embodiments, the abrasive particles can have a range or distribution of particle sizes. Such a distribution can be characterized by its median particle size. For instance, the median particle size of the abrasive particles may be at least 0.001 micrometers, at least 0.005 micrometers, at least 0.01 micrometers, at least 0.015 micrometers, or at least 0.02 micrometers. In some instances, the median particle size of the abrasive particles may be up to 300 micrometers, up to 275 micrometers, up to 250 micrometers, up to 150 micrometers, or up to 100 micrometers. In some examples, the median particle size of the abrasive particles is from about 1 micrometers to about 600 micrometers, from about 1 micrometers to about 300 micrometers, from about 1 micrometers to about 150 micrometers, from about 10 micrometers to about 600 micrometers, from about 10 micrometers to about 300 micrometers, from about 10 micrometers to about 150 micrometers, from about 50 micrometers to about 600 micrometers, from about 50 micrometers to about 300 micrometers, from about 50 micrometers to about 150 micrometers.

[0081] In some examples, the abrasive particle of the present disclosure may include formed abrasive particles. The formed abrasive particles may be present from 0.01 wt. percent to 100 wt, percent, from 0.1 wt. percent to 100 wt, percent, from 1 wt. percent to 100 wt, from 10 wt. percent to 100 wt, percent, from 0.01 wt. percent to 90 wt, percent, from 0.1 wt. percent to 90 wt, percent, from 1 wt. percent to 90 wt, from 10 wt. percent to 90 wt, percent, from 0.01 wt. percent to 75 wt, percent, from 0.1 wt. percent to 75 wt, percent, from 1 wt. percent to 75 wt, from 10 wt. percent to 75 wt, percent, based on the total weight of the abrasive particles.

[0082] In some examples, the particulate mixture comprises from about greater than 90 wt.% to about 99 wt.% abrasive particles (e.g., from about 91 wt.% to about 97 wt.%; about 92 wt.% to about 97 wt.%; about 95 wt.% to about 97 wt.%; or greater than about 90 wt.% to about 97 wt.%).

[0083] Abrasive particles are at least partially embedded (for example, by electrostatic coating) in the primer layer using any suitable method including electrostatic coating, drop coating, pattern coating using a production tool, as described for example in US PAP 2016 / 0311084, published on October 17, 2016, or any other suitable mechanical methods of mineral coating. In some embodiments, the abrasive particles can optionally be oriented under the influence of a magnetic field prior to the primer layer being cured.

[0084] In one method of electrostatic coating, as described in US PAP 2001 / 0049911, published December 13, 2001, which is incorporated herein by reference in its entirety, an (e.g. abrasive grain) particle can be deposited on an uncured or partially cured binder material. One common deposition technique involves electrostatic deposition in which the grain is projected upwards under the influence of an electrostatic field into contact with the binder. These processes may be described as UP (for upward projection) processes.

[0085] At block 460, the primer layer is cured. The curable primer layer may be thermally cured, UV-cured, or cured using another suitable technique. In embodiments where the masking agent is also a curable composition, the masking agent and the primer layer may cure using the different paced curing mechanisms, such that the masking agent is sufficiently cured so that the abrasive particles can be deposited onto the tacky primer layer. Alternatively, in some embodiments, the curable masking layer has a first curing mechanism while the curable primer layer has a second curing mechanism. The first and / or second curing mechanism may include UV-curing, IR-curing, thermal curing, or another suitable curing mechanism.

[0086] In some embodiments, the primer layer is applied to the backing as a hot melt extrusion and is heated to a temperature where it becomes tacky. The abrasive particles are then applied, and curing the primer layer in block 460 then involves allowing the primer to cool to a temperature where it is no longer tacky.

[0087] In embodiments where a removable masking agent is used, it may be removed prior to application of additional coatings over the cured primer layer.

[0088] At block 470, a make and / or size coat may be applied over the at least partially cured primer layer. The optional make coat and / or size coat in the abrasive articles of the present disclosure in any of their embodiments may be made from the same or different materials. Examples of these materials include amino resins, alkylated urea-formaldehyde resins, melamine-formaldehyde resins, and alkylated benzoguanamine-formaldehyde resin, acrylate resins (including acrylates and methacrylates) such as vinyl acrylates, acrylated epoxies, acrylated urethanes, acrylated polyesters, acrylated acrylics, acrylated polyethers, vinyl ethers, acrylated oils, and acrylated silicones, alkyd resins such as urethane alkyd resins, polyester resins, reactive urethane resins, epoxy resins such as bisphenol epoxy resins, isocyanates, isocyanurates, polysiloxane resins (including alkylalkoxysilane resins), reactive vinyl resins, phenolic resins (resole and novolac), and phenolic / latex resins. Theresins may be provided as monomers, oligomers, polymers, or combinations thereof. The primer layer improves adhesion between the polyester backing and the make layer. In some embodiments, the make layer is an alkylated urea-formaldehyde resin, and the size layer can be made from any of the resins described above. In some embodiments, the make layer is a phenolic layer as described above in any of its embodiments, and the size layer can be made from any of the resins described above. In some embodiments, both the make layer and the size layer are made from phenolic resins, which may be combined with a latex including any of those described above in any of the ratios described above.

[0089] Suitable phenolic resins are generally formed by condensation of phenol or an alkylated phenol (e.g., cresol) 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.

[0090] 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.

[0091] 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 Bostik of Ashland, Ohio 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). The uncured or partially cured resin composition 240A that is converted to cured resin composition 240 can compriseadditional components, including polyurethane dispersions, such as aliphatic and / or aromatic polyurethane dispersions. For example, polyurethane dispersions can comprise a polycarbonate polyurethane, a polyester polyurethane, or polyether polyurethane. The polyurethane can comprise a homopolymer or a copolymer.

[0092] Examples of commercially available polyurethane dispersions include aqueous aliphatic polyurethane emulsions available as NEOREZ R-960, NEOREZ R-966, NEOREZ R-967, NEOREZ R-9036, and NEOREZ R-9699 from DSM Neo Resins, Inc., Wilmington, Massachusetts; aqueous anionic polyurethane dispersions available as ESSENTIAL CC4520, ESSENTIAL CC4560, ESSENTIAL R4100, and ESSENTIAL R4188 from Essential Industries, Inc., Merton, Wisconsin; polyester polyurethane dispersions available as SANCURE 843, SANCURE 898, and SANCURE 12929 from Lubrizol, Inc. of Cleveland, Ohio; an aqueous aliphatic self-crosslinking polyurethane dispersion available as TURBOSET 2025 from Lubrizol, Inc.; and an aqueous anionic, co-solvent free, aliphatic self-crosslinking polyurethane dispersion, available as BAYHYDROL PR240 from Bayer Material Science, LLC of Pittsburgh, Pennsylvania.

[0093] Additional suitable commercially available aqueous polyurethane dispersions include:

[0094] 1) Alberdingk U 6150, a solvent-free, aliphatic polycarbonate polyurethane dispersion available from Alberdingk Boley GmbH, Krefeld, Germany, having a viscosity ranging from 50-500 mPa’s (according to ISO 1652, Brookfield RVT Spindle 1 / rpm 20 / factor 5), an elongation at break of about 200%, and a Koenig hardness after curing of about 65-70 s;

[0095] 2) Alberdingk U 6800, an aqueous, solvent-free, colloidal, low viscosity dispersion of an aliphatic polycarbonate polyurethane without free isocyanate groups available from Alberdingk Boley GmbH, Krefeld, Germany, having a viscosity ranging from 20-200 mPa-s (according to ISO 2555, Brookfield RVT Spindle 1 / rpm 50 / factor 2), an elongation at break of about 500%, and a Koenig hardness after curing of about 45 seconds;

[0096] 3) Alberdingk U 6100, an aqueous, colloidal, anionic, low viscosity dispersion of an aliphatic polyester-polyurethane without free isocyanate groups available from Alberdingk Boley GmbH, Krefeld, Germany, having a viscosity of 20-200 mPa-s (according to ISO 1652, Brookfield RVT Spindle 1 / rpm 50 factor 2), an elongation at break of about 300%, and a Koenig hardness after curing of about 50 s;

[0097] 4) Alberdingk U9800 - a solvent-free aliphatic polyester polyurethane dispersion available from Alberdingk Boley GmbH, Krefeld, Germany having a viscosity of 20-200 mPa’s (according to ISO 1652, Brookfield RVT Spindle 1 / rpm 20 / factor 5), and elongation at break of about 20-50%, and a Koenig hardness after curing of about 100-130 s; and

[0098] 5) Adiprene BL 16 - a liquid urethane elastomer with blocked isocyanate curing sites available from Chemtura, Middlebury, Connecticut.

[0099] Optional additives for polyurethane dispersions, as well as for curable compositions in general, include rheological modifiers, anti-foaming agents, water-based latexes and crosslinkers may be added to the aqueous polyurethane dispersion. Suitable crosslinkers include, for example, polyfimctional aziridine, methoxymethylolated melamine, urea resin, carbodiimide, polyisocyanate and blocked isocyanate. Additional water may also be added to dilute the formulation of the aqueous polyurethane dispersion, the phenolic resin, or combinations thereof. Curable compositions can be made, for example, from an aqueous polyurethane dispersion and a water-based latex.

[0100] The aqueous polyurethane dispersion contains less than about 20%, 10%, 5% or 2% organic solvent. In a specific embodiment, the aqueous polyurethane dispersion is substantially free of organic solvent. In some embodiments, it has been found that the aqueous polyurethane dispersion comprises at least about 7%, 15%, or 20% solids, and no greater than about 50% or 60% solids. The aqueous polyurethane dispersion may comprise no greater than about 80%, 85%, or 93% water. In some embodiments, it has been found that the aqueous polyurethane dispersion forms a film having a Koenig hardness of at least about 30 and no greater than about 200 seconds when measured according to ASTM 4366- 16. Further, in some embodiments, it has been found that the aqueous polyurethane dispersion may have a surface tension that is at least about 50% of the surface tension of water and no greater than about 300% of the surface tension of water. And in some embodiments, the aqueous polyurethane dispersion may have a viscosity of at least about 10 mPa s to no greater than about 600 mPa s, or at least about 70%, 80% or 90% of the viscosity of water and no greater than about 600%, 500% or 400% of the viscosity of water.

[0101] In addition, in some embodiments, the aqueous polyurethane dispersion may comprise at least about 100, 1000, or even at least about 10000 parts per million (ppm) of dimethylolpropionic acid. Optional additives including rheological modifiers, anti-foaming agents, and crosslinkers may be added to the aqueous polyurethane dispersion, for example. Suitable crosslinkers include, for example, polyfimctional aziridine, methoxymethylolated melamine, urea resin, carbodiimide, polyisocyanate and blocked isocyanate. Additional water may be added to reduce viscosity of the aqueous polyurethane dispersion. Likewise, addition of up to 10 percent by weight of organic solvent (e.g., propyl methyl ether or isopropanol) to the aqueous polyurethane dispersion may be used to reduce viscosity and / or improve the miscibility of ingredients.

[0102] The dispersed polyurethane can include at least one polycarbonate segment, although this is not a requirement.

[0103] The phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 91 to 99 percent by weight phenolic resin to 9 to 1 percent by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 56 to 91 percent by weight phenolic resin to 44 to 9 percent by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 62 to 91 percent by weight phenolic resin to 38 to 9 percent by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 69 to 91 percent by weight phenolic resin to 31 to 9 percent by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 56 to 83 percent by weight phenolic resin to 44 to 17 percent by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 56 to 76 percent by weight phenolic resin to 44 to 24 percent by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed in a solids weight ratio of 56 to 69 percent by weight phenolic resin to 44 to 31 percent by weight of polyurethane.

[0104] The make and / or size coat of the various embodiments described herein may further contain any of a number of additives. Such additives may be homogeneous orheterogeneous with one or more components in the composition. Heterogenous additives may be discrete (e.g., particulate) or continuous in nature.

[0105] Aforementioned additives can include, for example, surfactants (e.g., antifoaming agents such as ethoxylated nonionic surfactants such as DYNOL 604), pigments (e.g., carbon black pigment such as C-SERIES BLACK 7 LCD4115), fdlers (e.g. silicon dioxide Cabosil M5), synthetic waxes (e.g., synthetic paraffin MP22), stabilizers, plasticizers, tackifiers, flow control agents, cure rate retarders, adhesion promoters (for example, silanes such as (3-glycidoxypropyl)trimethoxysilane (GPTMS), and titanates), adjuvants, impact modifiers, expandable microspheres, thermally conductive particles, electrically conductive particles, and the like, such as silica, glass, clay, talc, colorants, glass beads or bubbles, and antioxidants, so as to, e.g., reduce the weight and / or cost of the structural layer composition, adjust viscosity, and / or provide additional reinforcement or modify the thermal conductivity of compositions and articles used in the provided methods or so that a more rapid or uniform cure may be achieved.

[0106] In some embodiments, the make and / or size coat can contain one or more fiber reinforcement materials. The use of a fiber reinforcement material can provide an abrasive layer having improved cold flow properties, limited stretchability, and enhanced strength. Preferably, the one or more fiber reinforcement materials can have a certain degree of porosity that enables a photoinitiator, when present, to be dispersed throughout, to be activated by UV light, and properly cured without the need for heat.

[0107] The one or more fiber reinforcements may comprise one or more fibercontaining webs including, but not limited to, woven fabrics, nonwoven fabrics, knitted fabrics, and a unidirectional array of fibers. The one or more fiber reinforcements could comprise a nonwoven fabric, such as a scrim.

[0108] Materials for making the one or more fiber reinforcements may include any fiber-forming material capable of being formed into one of the above-described webs. Suitable fiber-forming materials include, but are not limited to, polymeric materials such as polyesters, polyolefins, and aramids; organic materials such as wood pulp and cotton; inorganic materials such as glass, carbon, and ceramic; coated fibers having a core component (e.g., any of the above fibers) and a coating thereon; and combinations thereof.

[0109] Further options and advantages of the fiber reinforcement materials are described in U.S. Patent Publication No. 2002 / 0182955 (Weglewski et al.).

[0110] In some embodiments, the abrasive article of the various embodiments described herein include a size coat. In some examples, the size coat comprises the cured product of a phenolic size composition. In other examples, the size coat comprises the cured (e.g., photopolymerized) product of a bis-epoxide (e.g., 3,4-epoxy cyclohexylmethyl-3,4- epoxy cyclohexylcarboxylate, available from Daicel Chemical Industries, Ltd., Tokyo, Japan); a trifunctional acrylate (e.g., trimethylol propane triacrylate, available under the trade designation “SR351” from Sartomer USA, LLC, Exton, PA); an acidic polyester dispersing agent (e.g., “BYK W-985” from Byk-Chemie, GmbH, Wesel, Germany); a fdler (e.g., a sodium-potassium alumina silicate fdler, obtained under the trade designation “MINEX 10” from The Cary Company, Addison, IL.); a photoinitiator (e.g., a triarylsulfonium hexafluoroantimonate / propylene carbonate photoinitiator, obtained under the trade designation “CYRACURE CPI 6976” from Dow Chemical Company, Midland, MI; and an a-Hydroxyketone photoinitiator, obtained under the trade designation “DAROCUR 1173” from BASF Corporation, Florham Park, NJ).

[0111] At block 480, a supersize coat may be applied. Such additional coats may provide additional functionality, such as lubrication or grinding aid. In some embodiments, a supersize layer may be applied to at least a portion of the size layer. In general, the supersize coat is the outermost coating of the abrasive article and directly contacts the workpiece during an abrading operation.

[0112] One component of supersize coats can be a metal salt of a long-chain fatty acid (e.g., a C12-C22 fatty acid, a C14-C18 fatty acid, and a C16-C20 fatty acid). In some examples, the metal salt of a long-chain fatty acid is a stearate salt (e.g., a salt of stearic acid). The conjugate base of stearic acid is C17H35COO-, also known as the stearate anion. Usreful stearates include, but are not limited to, calcium stearate, zinc stearate, and combinations thereof.

[0113] The metal salt of a long-chain fatty acid can be present in an amount of at least 10 percent, at least 50 percent, at least 70 percent, at least 80 percent, or at least 90 percent by weight based on the normalized weight of the supersize coat (i.e., the average weight for a unit surface area of the abrasive article). The metal salt of a long -chain fatty acid can be present in an amount of up to 100 percent, up to 99 percent, up to 98 percent, up to 97 percent, up to 95 percent, up to 90 percent, up to 80 percent, or up to 60 percent by weight (e.g., from about 10 wt.% to about 100 wt.%; about 30 wt.% to about 70 wt.%; about50 wt.% to about 90 wt.%; or about 50 wt.% to about 100 wt.%) based on the normalized weight of the supersize coat.

[0114] Another component of the supersize coat is a polymeric binder, which, in some examples, enables the supersize coat to form a smooth and continuous fdm over the abrasive layer. In one example, the polymeric binder is a styrene-acrylic polymer binder. In some examples, the styrene-acrylic polymer binder is the ammonium salt of a modified styrene-acrylic polymer, such as, but not limited to, JONCRYL® LMV 7051. The ammonium salt of a styrene-acrylic polymer can have, for example, a weight average molecular weight (Mw) of at least 100,000 g / mol, at least 150,000 g / mol, at least 200,000 g / mol, or at least 250,000 g / mol (e.g., from about 100,000 g / mol to about 2.5 x 106 g / mol; about 100,000 g / mol to about 500,000 g / mol; or about 250,000 to about 2.5 x 106 g / mol).

[0115] The supersize coat may also have 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.

[0116] While grinding aids are described herein as used in the supersize layer, they may also be applied as part of the laminate layer.

[0117] 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.

[0118] Preferred grinding aids include halide salts, particularly potassium tetrafluoroborate (KBF4), cryolite (Na3AlF6), and ammonium cryolite [(NH4)3 A1F6] . 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.).

[0119] 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.).

[0120] 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. Nos. 3,833,346 (Wirth), 3,868,232 (Sioui et al.), and 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).

[0121] 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.

[0122] The supersize layer may also comprise other components and / or additives, such as abrasive particles, fillers, diluents, 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.

[0123] The minimum film-forming temperature, also referred to as MFFT, is the lowest temperature at which a polymer self-coalesces in a semi-dry state to form a continuous polymer film. In the context of the present disclosure, this polymer film can then function as a binder for the remaining solids present in the supersize coat. In some examples, the styrene-acrylic polymer binder (e.g., the ammonium salt of a styrene-acrylic polymer) has an MFFT that is up to 90°C, up to 80°C, up to 70°C, up to 65°C, or up to 60°C.

[0124] In some examples, the binder is dried at relatively low temperatures (e.g., at 70°C or less). The drying temperatures are, in some examples, below the melting temperature of the metal salt of a long-chain fatty acid component of the supersize coat. Use of excessively high temperatures (e.g., temperatures above 80°C) to dry the supersize coat is undesirable because it can induce brittleness and cracking in the backing, complicate web handling, and increase manufacturing costs. By virtue of its low MFFT, a binder comprised of, e.g., the ammonium salt of a styrene-acrylic polymer allows the supersize coat to achieve better film formation at lower binder levels and at lower temperatures without need for added surfactants such as DOWANOL® DPnP.

[0125] The polymeric binder can be present in an amount of at least 0.1 percent, at least 1 percent, or at least 3 percent by weight, based on the normalized weight of the supersize coat. The polymeric binder can be present in an amount of up to 20 percent, up to 12 percent, up to 10 percent, or up to 8 percent by weight, based on the normalized weight of the supersize coat. Advantageously, when the ammonium salt of a modified styrene acrylic copolymer is used as a binder, the haziness normally associated with a stearate coating is substantially reduced.

[0126] The supersize coats of the present disclosure optionally contain clay particles dispersed in the supersize coat. The clay particles, when present, can be uniformly mixed with the metal salt of a long chain fatty acid, polymeric binder, and other components of the supersize composition. The clay can bestow unique advantageous properties to the abrasive article, such as improved optical clarity and improved cut performance. The inclusion of clay particles can also enable cut performance to be sustained for longer periods of time relative to supersize coats in which the clay additive is absent.

[0127] The clay particles, when present, can be present in an amount of at least 0.01 percent, at least 0.05 percent, at least 0. 1 percent, at least 0.15 percent, or at least 0.2 percent by weight based on the normalized weight of the supersize coat. Further, the clay particles can be present in an amount of up to 99 percent, up to 50 percent, up to 25 percent, up to 10 percent, or up to 5 percent by weight based on the normalized weight of the supersize coat.

[0128] The clay particles may include particles of any known clay material. Such clay materials include those in the geological classes of the smectites, kaolins, illites, chlorites, serpentines, attapulgites, palygorskites, vermiculites, glauconites, sepiolites, and mixed layer clays. Smectites in particular include montmorillonite (e.g., a sodium montmorillonite or calcium montmorillonite), bentonite, pyrophyllite, hectorite, saponite, sauconite, nontronite, talc, beidellite, and volchonskoite. Specific kaolins include kaolinite, dickite, nacrite, antigorite, anauxite, halloysite, indellite and chrysotile. Illites include bravaisite, muscovite, paragonite, phlogopite and biotite. Chlorites can include, for example, corrensite, penninite, donbassite, sudoite, pennine and clinochlore. Mixed layer clays can include allevardite and vermiculitebiotite. Variants and isomorphic substitutions of these layered clays may also be used.

[0129] As an optional additive, abrasive performance may be further enhanced by nanoparticles (i.e., nanoscale particles) interdispersed (e.g., in the clay particles) in the supersize coat. Useful nanoparticles include, for example, nanoparticles of metal oxides, such as zirconia, titania, silica, ceria, alumina, iron oxide, vanadia, zinc oxide, antimony oxide, tin oxide, and alumina-silica. The nanoparticles can have a median particle size of at least 1 nanometer, at least 1.5 nanometers, or at least 2 nanometers. The median particle size can be up to 200 nanometers, up to 150 nanometers, up to 100 nanometers, up to 50 nanometers, or up to 30 nanometers.

[0130] Other optional components of the supersize composition include curing agents, surfactants, antifoaming agents, biocides, and other particulate additives known in the art for use in supersize compositions.

[0131] The supersize coat can be formed, in some examples, by providing a supersize composition in which the components are dissolved or otherwise dispersed in a common solvent. In some examples, the solvent is water. After being suitably mixed, the supersize dispersion can be coated onto the underlying layers of the abrasive article and dried to provide the finished supersize coat. If a curing agent is present, the supersize composition can be cured (e.g., hardened) either thermally or by exposure to actinic radiation at suitable wavelengths to activate the curing agent.

[0132] The coating of the supersize composition onto, e.g., the abrasive layer can be carried out using any known process. In some examples, the supersize composition is applied by spray coating at a constant pressure to achieve a pre-determined coating weight. Alternatively, a knife coating method where the coating thickness is controlled by the gap height of the knife coater can be used.

[0133] FIGS. 5A-5H illustrate example patterns for pattern coated abrasive particles in accordance with embodiments herein. However, while FIGS. 5A-5H illustrate some examples of patterns that may be used for depositing abrasive articles, it is expressly contemplated that these are by example only and that many other patterns are possible. Depositing abrasive particles onto a coated abrasive article in a pattern may provide a number of benefits. Spacing between abrasive particles may, for example, reduce loading on an abrasive article. Different patterns may also produce different finish quality - e.g. reduced haze, scratches, etc., depending on a substrate material. Pattern coating may also be useful as an anticounterfeit measure or as an indication of make / model of an abrasive article.

[0134] Abrasive articles according to the present disclosure may be converted, for example, into a belt, roll (e.g., tape roll), disc (e.g., perforated disc), or sheet. They may be used by hand or in combination with a machine such as a belt grinder. For belt applications, the two free ends of an abrasive sheet are joined together and spliced, thus forming an endless belt.

[0135] 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.

[0136] Unless specified otherwise herein, 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.

[0137] Unless specified otherwise herein, the term “substantially no” as used herein refers to a minority of, or mostly no, as in less than about 10%, 5%, 2%, 1%, 0.5%, 0.01%, 0.001%, or less than about 0.0001% or less.

[0138] Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range were explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Uikewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.

[0139] In this document, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting. Further, information that is relevant to a section heading may occur within or outside of that particular section. Furthermore, all publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.

[0140] In the methods described herein, the steps can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified steps can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed step of doing X and a claimed step of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0141] An abrasive article is presented that includes a backing having a first major side opposite a second major side, a primer layer directly coupled to the first major side of the backing, a plurality of abrasive particles coupled directly to the primer layer, and a coating layer applied over the plurality of abrasive particles.

[0142] The backing may include a film substrate, a paper substrate, or a cloth substrate.

[0143] The backing may include PET.

[0144] The primer layer may be extruded over the backing.

[0145] The primer layer may have a thickness less than 0.5 mm.

[0146] The primer layer may have a thickness less than 0.1 mm.

[0147] The primer layer may have a thickness less than 0.05 mm.

[0148] The primer layer may have a thickness greater than 0.02 mm.

[0149] The primer layer may include EAA or EVA.

[0150] The primer layer may include polyurethane.

[0151] The primer layer may include polyethylene.

[0152] The abrasive particles may be pattern coated.

[0153] The abrasive article may further include a masking component.

[0154] The masking component may include an ink.

[0155] The ink may be a UV -cured ink.

[0156] The coating layer may include a make coat.

[0157] The coating layer may include a size coat.

[0158] The coating layer may include a supersize coat.

[0159] The coating layer may include a phenolic resin.

[0160] The coating layer may include a grinding aid.

[0161] The coating layer may include a make coat, and the abrasive article may further include a size coat applied over the make coat.

[0162] The plurality of shaped abrasive particles may be oriented with respect to the backing.

[0163] The plurality of shaped abrasive particles may be aligned with respect to each other.

[0164] The abrasive article may further include a backsize applied to the second major side of the backing.

[0165] The backsize may include quartz.

[0166] The backsize may include calcium carbonate.

[0167] A method of making an abrasive article is presented that includes applying a primer layer to a first major side of a backing substrate. A masking component is applied to a first portion of the primer layer. A plurality of abrasive particles are deposited directly to the primer layer, with the deposition involving adhering the plurality of abrasive particles to a second portion of the primer layer. A coating layer is then coated over the deposited plurality of abrasive particles.

[0168] The masking component may be a curable masking component, and the method may further include at least partially curing the curable masking component.

[0169] Applying the primer layer may involve an extruded primer component.

[0170] The method may further include treating the backing substrate.

[0171] Treating the backing substrate may involve applying a backsize to the backing substrate.

[0172] The backsize may include quartz.

[0173] The backsize may include calcium carbonate.

[0174] The primer layer may include EAA or EVA.

[0175] The primer layer may include polyurethane.

[0176] The primer layer may include polyethylene.

[0177] The at least partially cured masking component may be sufficiently nontacky so that deposited abrasive particles are not coupled thereto.

[0178] The backing substrate may include a film substrate, a paper substrate, or a cloth substrate.

[0179] The backing substrate may include PET.

[0180] The primer layer may have a coating weight of less than 0.5 mm.

[0181] The primer layer may have a coating weight of less than 0. 1 mm.

[0182] The primer layer may have a coating weight of less than 0.05 mm.

[0183] The primer layer may have a coating weight of at least 0.02 mm.

[0184] Depositing the abrasive particles may involve pattern coating the abrasive particles.

[0185] The curable masking component may include an ink.

[0186] The ink may be a UV -cured ink.

[0187] The coating layer may include a make coat.

[0188] The coating layer may include a size coat.

[0189] The coating layer may include a supersize coat.

[0190] The coating layer may include a phenolic resin.

[0191] The coating layer may include a grinding aid.

[0192] The coating layer may include a make coat, and the method may further include coating a size coat applied over the make coat.

[0193] The plurality of shaped abrasive particles may be oriented with respect to the backing.

[0194] The plurality of shaped abrasive particles may be aligned with respect to each other.

[0195] A micro-finishing film is presented that includes a film backing includes a primer layer directly coupled to a first major surface of the film backing, a plurality of abrasive particles directly coupled to the primer layer, with the plurality of abrasive particles being pattern coated onto the primer layer, and a coating layer applied over the plurality of abrasive particles.

[0196] The film backing may include PET.

[0197] The primer layer may be extruded over the backing.

[0198] The primer layer may have a thickness of less than 0.5 mm.

[0199] The primer layer may include EAA or EVA.

[0200] The primer layer may include polyurethane.

[0201] The primer layer may include polyethylene.

[0202] The abrasive particles may be pattern coated.

[0203] The micro-finishing film may further include a masking component.

[0204] The masking component may include an ink.

[0205] The ink may be a UV -cured ink.

[0206] The coating layer may include a make coat.

[0207] The coating layer may include a size coat.

[0208] The coating layer may include a supersize coat.

[0209] The coating layer may include a phenolic resin.

[0210] The coating layer may include a grinding aid.

[0211] The coating layer may include a make coat, and the film may further include a size coat applied over the make coat.

[0212] The plurality of shaped abrasive particles may be oriented with respect to the backing.

[0213] The plurality of shaped abrasive particles may be aligned with respect to each other.

[0214] The micro-finishing film may further include a backsize.

[0215] The backsize may include quartz.

[0216] The backsize may include calcium carbonate.EXAMPLES

[0217] The examples described herein are intended solely to be illustrative, rather than predictive, and variations in the manufacturing and testing procedures can yield different results. All quantitative values in the Examples section are understood to be approximate in view of the commonly known tolerances involved in the procedures used. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom.

[0218] Unless stated otherwise, all reagents were obtained or are available from chemical vendors such as Sigma-Aldrich Company, St. Louis, Missouri, or may be synthesized by known methods. Unless otherwise reported, all ratios are by dry weight.

[0219] Materials used in the following Examples are described in Table 1, below.TABLE 1Example PreparationExample 1

[0220] Example 1 was prepared by the following flexographic printing method. A 22.9 cm by 22.9 cm piece of flexographic pattern 85 pm T / l 15 pm S 45°, where T refers to the “trace” or portion of the pattern covered with UV ink INK P, S refers to the length of the pattern uncovered by UV ink, and 45° refers to the angle of the stripes. The inked flexographic pattern was transferred to the ethylene acrylic acid copolymer primed side of a 30.5 cm wide roll of FILM 1. Next, the ink side of sample was irradiated with Fusion UV light, D bulb, 600 Watt / cm2at 7 meters per minute. The irradiate side of the sample was electrostatically coated with MN at 20 KV. Next, the sample was heated to 105°C for 1 hour and then cooled to room temperature. The loose mineral was removed with a 7.5 cm paint brush resulting in a coated mineral pattern with a mineral weight of about 20 gsm. Finally, the sample was coated with SR at a coat weight of about 12 gsm and cured at 90°C for 60 minutes and 102°C for 12 hours.Examples 2 & 3

[0221] Examples 2 & 3 were prepared using the same procedure as in Example 1 except for changes in flexographic pattern and UV ink, as shown in Table 2.Table 2

[0222] SEM images of Example 1 are shown in FIGS. 6A-6B. SEM images of Example 3 are shown in FIGS. 6C-6D.Comparative Example PreparationComparative Example A

[0223] Comparative Example A by prepared by taking a 30.5 cm x 30.5 cm sample of FILM 1 and electrostatically coating the ethylene acrylic acid copolymer primed side with MN. Next, the sample was heated to 105 °C for 1 hour and then cooled to room temperature. The loose mineral was removed with 75 mm paint brush resulting in a random mineral pattern with a mineral weight of about 33 gsm. Finally, the sample was coated with SR at a coat weight of about 12 gsm and cured at 90°C for 60 minutes and 102°C for 12 hours.Comparative Example B

[0224] Comparative Example B is 372L 20 um Lot OR2 Microfmishing Film commercially available from 3M, St Paul, MN.

[0225] FIGS. 6E-6F illustrate SEM images of Comparative Example A.Abrasive Performance Test

[0226] Comparative Example B and Examples 1,2 and 3 were cut into 1.9 cm x 15.5 cm samples for testing. The abrasive performance test consists of taking a 5150-alloy steel ring with a 10.2 cm diameter center hole of 6.4 cm and thickness of 1.6 cm, The ring was precondition with 372L 40 pm Micro Finishing Film, available from 3M Company™ prior to each test. The preconditions rings were weighed prior to each test. The ring was placedonto a shaft and secured with a nut. Abrasive samples were threaded into an arch shaped holder with sample contacting 25% of ring top. The pressure for sample contacting ring was set to 10 psi, the ring is spun at 120 rpm, and water is dripped slowly onto ring. Samples were placed in contact with rotating ring and the test was complete when the ring rotated clockwise for 7 seconds and counterclockwise for 7 seconds. The machine was stopped, the ring was removed, wiped with dry cloth, weighed and surface finish Ra and Rtm were measured in three different locations with a Surtronic® profilometer and recorded. This test was conducted on Comparative B and Examples 1, 2, and 3. The abrasive performance results are displayed in Table 3, which shows Example 1 exceeding the total cut performance of Comparative Example B.Table 3

[0227] SEM images of Example 1 after testing are illustrated in FIGS. 7A-7B. SEM images of Example 2 after testing are illustrated in FIGS. 7C-7D. SEM images of Example 3 are illustrated in FIGS. 7E-7F.

Claims

What is claimed is:

1. An abrasive article comprising: a backing having a first major side opposite a second major side; a primer layer directly coupled to the first major side of the backing; a plurality of abrasive particles coupled directly to the primer layer; and a coating layer applied over the plurality of abrasive particles.

2. The abrasive article of claim 1, wherein the backing comprises a film substrate, a paper substrate, or a cloth substrate.

3. The abrasive article of claim 1 or 2, wherein the backing comprises PET.

4. The abrasive article of any of claims 1-3, wherein the primer layer is extruded over the backing.

5. The abrasive article of any of claims 1-4, wherein the primer layer has a thickness less than 0.5 mm.

6. The abrasive article of any of claims 1-5, wherein the primer layer has a thickness less than 0.1 mm.

7. The abrasive article of any of claims 1-6, wherein the primer layer has a thickness less than 0.05 mm.

8. The abrasive article of any of claims 1-7, wherein the primer layer has a thickness greater than 0.02 mm.

9. The abrasive article of any of claims 1-8, wherein the primer layer comprises EAA or EVA.

10. The abrasive article of any of claims 1-9, wherein the primer layer comprises polyurethane.

11. The abrasive article of any of claims 1-10, wherein the primer layer comprises polyethylene.

12. The abrasive article of any of claims 1-11, wherein the abrasive particles are pattern coated.

13. The abrasive article of any of claims 1-12, and further comprising a masking component.

14. The abrasive article of claim 13, wherein the masking component comprises an ink.

15. The abrasive article of claim 14, wherein the ink is a UV-cured ink.

16. The abrasive article of any of claims 1-15, wherein the coating layer comprises a make coat.

17. The abrasive article of any of claims 1-16, wherein the coating layer comprises a size coat.

18. The abrasive article of any of claims 1-17, wherein the coating layer comprises a supersize coat.

19. The abrasive article of any of claims 1-18, wherein the coating layer comprises a phenolic resin.

20. The abrasive article of any of claims 1-19, wherein the coating layer comprises a grinding aid.

21. The abrasive article of any of claims 1-20, wherein the coating layer comprises a make coat, and further comprising a si ze coat applied over the make coat.

22. The abrasive article of any of claims 1-21, wherein the plurality of shaped abrasive particles are oriented with respect to the backing.

23. The abrasive article of any of claims 1-22, wherein the plurality of shaped abrasive particles are aligned with respect to each other.

24. The abrasive article of any of claims 1-23, and further comprising a backsize applied to the second major size of the backing.

25. The abrasive article of claim 24, wherein the backsize comprises quartz.

26. The abrasive article of claim 24, wherein the backsize comprises calcium carbonate.

27. A method of making an abrasive article, the method comprising: applying a primer layer to a first major side of a backing substrate; applying a masking component to a first portion of the primer layer; depositing a plurality of abrasive particles directly to the primer layer, wherein depositing comprises adhering the plurality of abrasive particles to a second portion of the primer layer; and coating a coating layer over the deposited plurality of abrasive particles.

28. The method of claim 27, wherein the masking component is a curable masking component and wherein the method at least further comprises: at least partially curing the curable masking component.

29. The method of claim 27 or 28, wherein applying the primer layer comprises an extruded primer component.

30. The method of any of claims 27-29, and further comprising; treating the backing substrate.

31. The method of claim 30, wherein treating comprises applying a backsize to the backing substrate.

32. The method of claim 31, wherein the backsize comprises quartz.

33. The method of claim 31, wherein the backsize comprises calcium carbonate.

34. The method of any of claims 27-33, wherein the primer layer comprises EAA or EVA.

35. The method of any of claims 27-34, wherein the primer layer comprises polyurethane.

36. The method of any of claims 27-35, wherein the primer layer comprises polyethylene.

37. The method of any of claims 28-36, wherein the at least partially cured masking component is sufficiently nontacky that deposited abrasive particles are not coupled thereto.

38. The method of any of claims 27-37, wherein the backing substrate comprises a film substrate, a paper substrate, or a cloth substrate.

39. The method of any of claims 27-38, wherein the backing substrate comprises PET.

40. The method of any of claims 27-39, wherein the primer layer has a thickness less than 0.5 mm.

41. The method of any of claims 27-40, wherein the primer layer has a thickness less than 0.1 mm.

42. The method of any of claims 27-41, wherein the primer layer has a thickness less than 0.05 mm.

43. The method of any of claims 27-42, wherein the primer layer has a thickness of at least 0.25 mm.

44. The method of any of claims 27-43, wherein depositing the abrasive particles comprises pattern coating the abrasive particles.

45. The method of any of claims 28-44, wherein the curable masking component comprises an ink.

46. The method of claim 45, wherein the ink is a UV-cured ink.

47. The method of any of claims 27-46, wherein the coating layer comprises a make coat.

48. The method of any of claims 27-47, wherein the coating layer comprises a size coat.

49. The method of any of claims 27-48, wherein the coating layer comprises a supersize coat.

50. The method of any of claims 27-49, wherein the coating layer comprises a phenolic resin.

51. The method of any of claims 27-50, wherein the coating layer comprises a grinding aid.

52. The method of any of claims 27-51, wherein the coating layer comprises a make coat, and further comprising: coating a size coat applied over the make coat.

53. The method of any of claims 27-52, wherein the plurality of shaped abrasive particles are oriented with respect to the backing.

54. The method of any of claims 27-53, wherein the plurality of shaped abrasive particles are aligned with respect to each other.

55. A micro-finishing film comprising: a film backing; a primer layer directly coupled to a first major surface of the film backing; a plurality of abrasive particles directly coupled to the primer layer, the plurality of abrasive particles being pattern coated onto the primer layer; and a coating layer applied over the plurality of abrasive particles.

56. The micro-finishing film of claim 55, wherein the backing comprises PET.

57. The micro-finishing film of claim 55 or 56, wherein the primer layer is extruded over the backing.

58. The micro-finishing film of any of claims 55-57, wherein the primer layer has thickness of less than 0.5 mm.

59. The micro-finishing film of any of claims 55-58, wherein the primer layer has thickness of less than 0.1 mm.

60. The micro-finishing film of any of claims 55-59, wherein the primer layer has thickness of less than 0.05 mm.

61. The micro-finishing film of any of claims 55-60, wherein the primer layer has thickness of at least 0.02 mm.

62. The micro-finishing film of any of claims 55-61, wherein the primer layer comprises EAA or EVA.

63. The micro-finishing film of any of claims 55-62, wherein the primer layer comprises polyurethane.

64. The micro-finishing film of any of claims 55-63, wherein the primer layer comprises polyethylene.

65. The micro-finishing film of any of claims 55-64, wherein the abrasive particles are pattern coated.

66. The micro-finishing film of any of claims 55-65, and further comprising a masking component.

67. The micro-finishing film of claim 66, wherein the masking component comprises an ink.

68. The micro-finishing film of claim 67, wherein the ink is a UV-cured ink.

69. The micro-finishing film of any of claims 55-68, wherein the coating layer comprises a make coat.

70. The micro-finishing film of any of claims 55-69, wherein the coating layer comprises a size coat.

71. The micro-finishing film of any of claims 55-70, wherein the coating layer comprises a supersize coat.

72. The micro-finishing film of any of claims 55-71, wherein the coating layer comprises a phenolic resin.

73. The micro-finishing film of any of claims 55-72, wherein the coating layer comprises a grinding aid.

74. The micro-finishing film of any of claims 55-73, wherein the coating layer comprises a make coat, and further comprising a size coat applied over the make coat.

75. The micro-finishing film of any of claims 55-74, wherein the plurality of shaped abrasive particles are oriented with respect to the backing.

76. The micro-finishing film of any of claims 55-75, wherein the plurality of shaped abrasive particles are aligned with respect to each other.

77. The micro-finishing film of any of claims 55-76, and further comprising abacksize.

78. The micro-finishing film of claim 77, wherein the backsize comprises quartz.

79. The micro-finishing film of claim 77, wherein the backsize comprises calcium carbonate.

Images