Patent Description:
<CIT> discloses abrasive articles wherein the make layer, abrasive particle layer, and size layer are coated onto a backing according to a coating pattern of discrete islands, wherein further a pervasive uncoated area extending across the backing is provided. <CIT> discloses an abrasive sheet formed by uniformly painting a slurry made of a mixture of abrasive particles and adhesives on a surface of a base sheet with a pattern of irregularities formed by embossing. The slurry layer on the sheet hardens by drying to form an abrasive layer, which has high and low abrasive parts, corresponding to the irregularities of the base sheet. <CIT> describes an abrasive pad, which includes a hydrophobic polymer as a base material and in which a graft-polymer chain having a hydrophilic group is introduced into the surface of the hydrophobic polymer.

There is a continuing need for abrasive articles that provide enhanced cut and/or useful abrading life while demonstrating superior dust extraction. The present invention provides an abrasive article according to claim <NUM> and a method according to claim <NUM>. Advantageously, abrasive articles according to the present disclosure provide dust-extraction benefits of an abrasive with a porous construction, but also provides superior abrasive performance such as cut, surface finish and/or useful abrading life.

As used herein:
The term "surface free energy" refers to a quantitative measure of the surface tension of a solid, caused by intermolecular interactions at an interface, such as London dispersive force, Debye inductive force, Keesom orientational forces, hydrogen bonding, Lewis acid-base interactions, and energetically homogeneous and heterogeneous interactions.

The term "portion" refers to a part of a whole. A portion can be a section, a plurality of areas, or a set of sections that having localized properties.

The term "hydrophobic" describes an observed tendency of substances to aggregate in an aqueous medium and exclude water molecules. The hydrophobic effect can describe the segregation of water, which maximizes hydrogen bonding between molecules of water and minimizes the area of contact between water and nonpolar molecules. If a water droplet on a surface of a material has a static contact angle of more than <NUM> degrees, the surface of the material is considered hydrophobic.

The term "hydrophilic" describes an observed tendency of substances to mix with, dissolve in, or be wet by water. Interactions of a hydrophilic molecule, or part of a molecule, with water and other polar substances are more thermodynamically favorable than their interactions with oil or other hydrophobic substances. If a water droplet on a surface of a material has a static contact angle of less than or equal to <NUM> degrees, preferably less than <NUM> degrees, and more preferably less than <NUM> degrees, the surface of the material is considered hydrophilic.

The term "ambient conditions" refers to a temperature of <NUM> degrees Celsius (<NUM> Kelvins, <NUM> degrees Fahrenheit) and an absolute pressure of <NUM> Standard atmospheric pressure (<NUM> atm, <NUM> kilopascals).

Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope of the present invention as defined by the claims.

Embodiments described herein are directed to abrasive articles that have the dust-extraction advantages of an abrasive on a net-type backing, but also provides superior abrasive performance (cut, surface finish and/or useful abrading life) advantages of a conventional abrasive.

This combination of benefits is possible because the construction of the abrasive articles described herein allows for a non-coextensive abrasive coating on a porous backing to form patterned areas of abrasive coating as well as open areas devoid of any abrasive coating. The abrasive area can be randomly and sporadically distributed across the abrasive article, or according to a predetermined pattern. The abrasive area can be designed independently of any abrasive layer pattern present on the porous substrate, optimizing both abrasive performance and dust extraction.

Embodiments herein also apply to method of making abrasive articles, particularly mesh-type backed abrasive articles.

Referring now to <FIG>, the abrasive article <NUM> includes a porous substrate <NUM> comprising strands forming first void spaces <NUM> between the strands (see <FIG>). Abrasive element <NUM> comprises cured resin <NUM> and abrasive particles <NUM> attached to cured resin <NUM>. Abrasive element <NUM> is joined to porous substrate <NUM>. A plurality of void spaces extends through the porous substrate <NUM> adjacent to and/or between abrasive element(s) <NUM>.

The plurality of void spaces coinciding with void spaces in the porous substrate <NUM> allow for an air flow through the article <NUM> during normal use at a rate of, e.g., at least <NUM>/s (e.g., at least <NUM>/s, at least <NUM>/s, at least <NUM>/s, at least <NUM>/s; or about <NUM>/s to about <NUM>/s, about <NUM>/s to about <NUM>/s, about <NUM>/s to about <NUM>/s, about <NUM>/s to about <NUM>/s, about <NUM>/s or about <NUM>/s), such that, when in use, dust can be removed from an abraded surface through the abrasive article.

Referring to <FIG>, abrasive article <NUM> includes a porous substrate <NUM> comprising strands <NUM> forming first void spaces <NUM>. Laminate <NUM> is joined to porous substrate <NUM> through first surface <NUM> of laminate <NUM>. Cured make resin <NUM> is joined to laminate <NUM> opposite porous substrate <NUM> through second surface <NUM>. Abrasive particles <NUM> are joined to make resin <NUM>. A plurality of second void spaces <NUM> extends through the laminate coinciding with first void spaces <NUM>.

In some instances, the abrasive article comprises laminate 230A, which does not comprise a cured make resin joined to laminate 230A.

In some embodiments, the abrasive particles are at least partially embedded in the cured resin composition. As used herein, the term "at least partially embedded" generally means that at least a portion of an abrasive particle is embedded in the cured resin composition, such that, the abrasive particle is anchored in the cured resin composition. In some embodiments, abrasive particles are coated onto the laminate together in the form of a slurry composition.

Referring now to <FIG>, abrasive article <NUM> incorporates all of the features shown in <FIG>, which will not be discussed again for the sake of brevity. Abrasive article <NUM> comprises first side <NUM> joined to laminate <NUM>. Second side <NUM> is opposite first side <NUM>. In some embodiments, the second side <NUM> can include at least a part of an attachment system <NUM>. In some embodiments, the attachment system <NUM> can be a two-part mechanical fastening system. For example, <FIG> depicts a loop layer of a two-part hook and loop attachment system. In some embodiments, abrasive article <NUM> also include size layer <NUM> having size layer void spaces <NUM>, which coincide with second void spaces <NUM>. In some embodiments, abrasive article <NUM> also includes optional supersize layer <NUM> overlaying size layer <NUM>. The optional supersize layer <NUM> has supersize layer void spaces <NUM>, which coincide with size coat void spaces <NUM> and second void spaces <NUM>.

The layer configurations described herein are not intended to be exhaustive, and it is to be understood that layers can be added or removed with respect to any of the examples depicted in <FIG>. It should also be understood that abrasive articles could take any form, for example, circular discs, sheets or belts.

<FIG> show the various embodiments (not exhaustive) of the possible structures of the laminate <NUM>, cured resin composition <NUM>, abrasive particles <NUM>, and strands <NUM>. For example, the laminate <NUM> can at least partially wrap around the strands <NUM> to create second void spaces <NUM>. And in some instances, the laminate <NUM> can wrap around some stands <NUM> and not others. In various instances, the laminate <NUM> can be at least partially covered by cured resin composition <NUM>, or may not be covered by cured resin composition <NUM>.

The abrasive articles of the various embodiments described herein include a porous substrate. The porous substrate may be constructed from any of a number of materials known in the art for making coated abrasive articles. Although not necessarily so limited, porous substrate <NUM> can have a thickness of at least <NUM> millimeters, at least <NUM> millimeters, <NUM> millimeters, <NUM> millimeters, or <NUM> millimeters. The backing could have a thickness of up to <NUM> millimeters, up to <NUM> millimeters, up to <NUM> millimeters, up to <NUM> millimeters, or up to <NUM> millimeters.

The porous substrate can be flexible and has voids spaces (e.g., void spaces between strands) such that it is porous. Flexible materials from which the porous substrate can be made include cloth (e.g., cloth made from fibers or yarns comprising polyester, nylon, silk, cotton, and/or rayon, which may be woven, knit or stitch bonded) and scrim. The porous substrate can comprise a loop backing.

Exemplary porous substrates include knit fabrics (e.g., knit fabrics having a volume porosity of at least <NUM> percent, at least <NUM> percent, at least <NUM> percent, at least <NUM> percent, at least <NUM> percent, or even at least <NUM> percent), open weave fabrics, woven meshes/screens (e.g., wire mesh or fiberglass mesh), porous nonwoven fabrics, unitary meshes (e.g., unitary continuous plastic screens), perforated polymeric films, and perforated nonporous (e.g., sealed) fabrics. In some embodiments, the porous substrate may comprise an integral loop substrate, especially in the case of knit fabrics.

Porous fabric substrates can be made from any known fibers, whether natural, synthetic, or a blend of natural and synthetic fibers. Examples of useful fiber materials include fibers or yarns comprising polyester (e.g., polyethylene terephthalate), polyamide (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, vinyl chloride-acrylonitrile copolymers, graphite, polyimide, silk, cotton, linen, jute, hemp, and/or rayon. Useful fibers may be of virgin materials or of recycled or waste materials reclaimed from garment cuttings, carpet manufacturing, fiber manufacturing, or textile processing, for example. Useful fibers may be homogenous or a composite such as a bicomponent fiber (for example, a co-spun sheath-core fiber). The fibers may be tensilized and crimped, but may also be continuous filaments such as those formed by an extrusion process.

Porous film substrates may comprise perforated polymer films comprising, for example, polyester (e.g., polyethylene terephthalate), polyamide (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, and/or vinyl chloride-acrylonitrile copolymers. Perforation may be provided by die punching, needle punching, knife cutting, laser perforating, and slitting as described in <CIT>) and <CIT>), for example. Perforation may also be provided by applying a flame, a heat source, or pressurized fluid, as described in <CIT>) and <CIT>), for example.

The porous substrate can be rigid, semi-rigid, or flexible. The porous substrate has openings that extend through its body between two opposed major surfaces. The openings may be perforations or spaces between fiber strands of a porous, for example.

The openings in the porous substrate should be of sufficient size, which may be the same or different, that swarf generated during abrading operations can be drawn by vacuum through the openings and away from the surface of a workpiece being abraded. In some embodiments, the openings are of sufficient size that some or all of them allow passage of swarf particles with an average diameter of less than or equal to <NUM> millimeter (mm), less than or equal to <NUM>, less than or equal to <NUM>, less than or equal to <NUM>, less than or equal to <NUM>, less than or equal to <NUM>, less than or equal to <NUM>, or even less than or equal to <NUM> through the porous substrate.

The porous substrate can have a thickness of at least <NUM>, at least <NUM>, at least <NUM>, at least <NUM>, or even at least <NUM>, although this is not a requirement. Likewise, the porous substrate may have a thickness of up to <NUM>, up to <NUM>, up to <NUM>, up to <NUM>, or up to <NUM> in any combination with the preceding lower limits, although this is not a requirement.

Generally, the strength of the porous substrate should be sufficient to resist tearing or other damage during abrading processes. The thickness and smoothness of the porous substrate should also be suitable to provide the desired thickness and smoothness of the abrasive article; for example, depending on the intended application or use of the abrasive article.

The porous substrate may have any basis weight; for example, in a range of from <NUM> to <NUM> grams per square meter (gsm), more typically <NUM> to <NUM> gsm, and even more typically <NUM> to <NUM> gsm. To promote adhesion of the functional layer to the porous substrate, one or more surfaces of the porous substrate may be modified by known methods including corona discharge, ultraviolet light exposure, electron beam exposure, flame discharge, and/or scuffing.

In some embodiments, the porous substrate may be treated using, e.g., chemical treatment, corona treatment such as air or nitrogen corona, plasma, flame, or actinic radiation. The benefit of the treatment can be, for example, enhancing adhesion between the backing and an applied layer, such as a make layer or a laminate. It is expressly contemplated that such pretreatments can also be applied to a backing layer of abrasive articles described herein in addition to, or prior to, application of a laminate. Some examples of substrate treatments are described in commonly-owned pending PCT Pat. No. <CIT> (Koenig et al. ), and <CIT>.

The nature of the laminate is also non-limiting. Generally speaking, the laminate can be in any form (e.g., a nonwoven or woven web or a film) that provides a substantially flat landing for uncured (or partially cured) resin composition 240A, such that uncured resin composition 240A that is deposited on the laminate <NUM> remains on the surface and does not have an opportunity to, for example, move into the void spaces <NUM> between strands <NUM> of porous substrate <NUM>; but at the same time migrates away from the void spaces <NUM> between strands <NUM>, for example, during the curing process that forms cured resin composition <NUM>, thereby opening a plurality of second void spaces <NUM> extending through the laminate coinciding with first void spaces <NUM>.

The laminate may be provided, for example, in the form of a continuous non-apertured sheet, or as a continuous apertured sheet whereby apertures are provided in areas adjacent to or surrounding the abrasive element(s). In either case, the laminate provides a substantially flat landing for uncured (or partially cured) resin composition 240A. The laminate <NUM> used herein may be opaque or transparent or translucent to visible light. They may be flexible or inflexible. For example, the laminate <NUM> may be a flexible sheet made using conventional filmmaking techniques such as extrusion of a laminate resin into a sheet and optional uniaxial or biaxial orientation.

The laminate <NUM> in this disclosure includes a second surface <NUM>, where a make resin <NUM> joined to and generally opposite to a first surface <NUM> of the laminate <NUM>. The second surface <NUM> comprises at least two portions having different surface free energies. For example, a first portion of the surface of the laminate has a first surface free energy, a second portion of the surface of the laminate has a second surface free energy, and the first surface free energy is different from the second surface free energy. In some embodiments, each of the first portion and the second portion can comprise a plurality of discrete surface areas. In some other embodiments, each of the first portion and the second portion can comprise interconnected surface sections. In some embodiments, the first portion and the second portion can be arrayed in at least one pattern on the second surface <NUM>. In some of these embodiments, the pattern can be predetermined or controlled.

Surface free energy is commonly calculated through contact angle measurements using known measurement methods. A static contact angle is the angle that connects the solid-liquid interface and the liquid-gas interface when the contact area between liquid and solid is not changed from the outside during the measurement. In these methods, the static contact angle of a surface is measured with liquids, such as water-based liquids or organic solvent-based liquids, usually by a static contact angle meter. For example, surface free energy can be obtained according to ASTM D <NUM> - (<NUM>) (Reapproved <NUM>) "Standard Test Method for Surface Wettability and Absorbency of Sheeted Materials Using an Automated Contact Angle Tester", ASTM International, West Conshohocken, Pennsylvania. Static contact angle measurement gives an indication on how a liquid wet the surface. At ambient conditions, when a static contact angle is smaller than <NUM> degree, high wetting occurs, while when a static contact angle is larger than <NUM> degree but less than <NUM> degree, low wetting occurs. When a static contact angle is <NUM> degree, it is considered the surface is not wetted as all. Surfaces with high surface free energy are more easily wetted than surfaces with low surface free energy.

The surface free energies of various portions of laminate surface are typically different. In some embodiments, the difference of between surface free energies of two different portions can be at least about <NUM> millinewton per meter (mN/m), <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, and preferably about <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m, <NUM> mN/m <NUM> mN/m, or even at least about <NUM> mN/m at ambient conditions.

Suitable materials for the laminate can be non-limiting. A variety of laminate materials that include an organic polymer can be used herein. The entire laminate may be made of organic polymer materials, or the laminate may have a surface of such polymer materials. Whether just on a surface of a laminate or forming the entire laminate, the laminate materials provide phases of separation on the surface, resulting in portions with localized properties, such as surface free energies. In various embodiments, the laminate comprises hot-melt materials, for example, polyester hot-melt materials (e.g., PE85 Polyester Hot Melt Web Adhesive available from Bostik, Wauwatosa, Wisconsin). In many embodiments, the laminate comprises at least two different polymers, i.e., a first polymer and a second polymer. A first portion of the surface with a first surface free energy is formed of the first polymer, a second portion of the surface with a second surface free energy is formed of the second polymer. In some embodiments, the laminate comprises three or more laminate materials, forming additional portions with different second surface free energies.

The terms "polymer" and "polymer material" include, but are not limited to, organic homopolymers, copolymers, such as for example, block, graft, random, and copolymers, terpolymers, etc., and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometrical configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic symmetries.

A variety of polymer materials can be used herein. In one embodiment, the laminate comprises a hot-melt polymer. Examples include polyamides, polyesters, poly(ethylene-acrylic acid) copolymers, poly(ethylene-acrylate) copolymers, poly(ethylene-methyl acetate) copolymers, polyolefins, polyurethane-polyethylene-vinyl acetate terpolymers, polyethylene acrylate copolymers, ethylene methacrylic acid copolymers, acid-modified ethylene terpolymers, anhydride-modified ethylene acylates, vinyl acetate polymer, and combinations thereof. The laminate may also contain an additive, such as ethyl acetoacetate. In one embodiment, the laminate contains at least <NUM>% ethyl acetoacetate.

In one embodiment, the laminate material has a melting temperature between about <NUM> to about <NUM>. In another embodiment the laminate material has a melting temperature between about <NUM> to about <NUM>.

In many embodiments, the laminate comprises hydrophobic or hydrophilic polymer materials. In some embodiments, the laminate comprises both hydrophobic and hydrophilic polymers.

Illustrative examples of suitable (hydrophobic) materials include organic polymers such as polyesters (such as polyethylene terephthalate, polybutylene terephthalate, polycarbonates, allyl diglycol carbonate, polyacrylates (e.g., polymethyl methacrylate), polystyrenes, polyvinyl chlorides, polysulfones, polyethersulfones, polyphenylethersulfones, polyethers, epoxy addition polymers with polydiamines or polydithiols, polyolefins (polypropylene, polyethylene, and polyethylene copolymers), fluorinated polymers (e.g., tetrafluoroethylene/hexafluoropropylene/vinylidene fluoride terpolymers, polyvinylidene fluorides, and polyvinyl fluorides), and cellulose esters (e.g., cellulose acetates or cellulose butyrates), and combinations thereof (e.g., including blends and laminates thereof). A preferred material comprises polyethylene terephthalate.

Illustrative examples of other suitable (more hydrophilic) materials include organic polymers such as homopolymers and copolymers of N-isopropylacrylamide homopolymers and copolymers (e.g., poly(N-isopropylacrylamide-co-butyl acrylate) and poly(N-isopropylacrylamide-co-methacrylic acid)), polyacrylamide and copolymers (such as poly(acrylamide-co-acrylic acid)), polyoxazolines (e.g., poly(-methyl-<NUM>-oxazoline) and poly(-ethyl-<NUM>-oxazoline)), polyamides, homopolymers and copolymers of poly(acrylic acid) (e.g., poly(acrylic acid-co-maleic acid)), poly(methacrylic acid) copolymers (e.g., poly(N-isopropylacrylamide-co-methacrylic acid)), polymethacrylates (e.g., poly(hydroxypropyl methacrylate)), homopolymers and copolymers of ethylene glycol (e.g., polyethylene glycol, polyethylene-block-poly(ethylene glycol) and polyethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol)), poly(vinyl alcohol) and related copolymers (such as poly(vinyl alcohol-co-ethylene)), poly(vinyl pyrrolidinone) and copolymers (e.g., poly(<NUM>-vinylpyrrolidone-co-styrene) and poly(<NUM>-vinylpyrrolidone-co-vinyl acetate)), maleic anhydride copolymers (e.g., poly(ethylene-alt-maleic anhydride)), polyether (such as poly(methyl vinyl ether)) and copolymers (e.g., poly(methyl vinyl ether-alt-maleic acid)).

The surface of the laminate can also comprise a superhydrophilic portion in some embodiments. A superhydrophilic surface is defined as having a static contact angle of water of <NUM> degrees or less under ambient conditions. In these embodiments, the laminate can comprise suitable superhydrophilic materials prepared from compositions that include one or more compounds with hydrophilic-functional group(s). The hydrophilic groups render hydrophilicity to the surface. Suitable hydrophilic functional groups may include sulfonate groups, sulfate groups, phosphate groups, phosphonate groups, carboxylate groups, gluconamide-containing groups, sugar-containing groups, polyvinyl alcohol-containing groups, and quaternary ammonium groups. In certain embodiments, the hydrophilic groups are selected from sulfur-based acids and/or their conjugate bases (e.g., -SO<NUM>- or -SO<NUM>H), phosphorus-based acids and/or their conjugate bases (e.g., -OPO<NUM><NUM>-, -OPO<NUM>H- -OPO<NUM>H<NUM>, -PO<NUM>H, or -PO<NUM><NUM>-), and carboxylic acids and/or their conjugate bases (e.g., -CO<NUM>H or -CO<NUM>-). In certain embodiments, the superhydrophilic surface layer includes sulfonate groups (i.e., sulfonate functionality). These materials can also have alkoxysilane-functional and/or silanol-functional groups. For certain embodiments, the hydrophilic-containing compounds are zwitterionic and for certain embodiments, they are non-zwitterionic. Other superhydrophilic materials are disclosed in commonly-owned U. No. <NUM>/<NUM> (Jing et al.

In some embodiments, the second surface of laminate may be treated using, for example, chemical treatment, corona treatment such as air or nitrogen corona, plasma, flame, or actinic radiation. The purpose of surface treatment may vary. One example of the purpose can be to improve adhesion to an overlying coating or to a substrate, or to change a property of the surface, such as surface free energy. Examples of changing the surface free energy by chemical treatment include the application of metal salt paraffin dispersion, polysiloxane, fluorocarbon polymers, and the combination thereof.

In some embodiments, the laminate can comprise inorganic materials. Examples of inorganic materials include, but not limited to, siliceous materials, silica (including organo-modified silica and unmodified nonporous spherical silica), ceramics, metal salts, inorganic composite, glass, minerals, and the combination thereof.

A variety of other ingredients may also be incorporated in the laminate compositions.

In one embodiment the coating weight of the laminate is between about <NUM> and about <NUM> grams per square meter (gsm). In one embodiment the coating weight of the laminate is between about <NUM> gsm and about <NUM> gsm. In one embodiment, the coating weight of the laminate is between about <NUM> gsm and about <NUM> gsm. The coating thickness of the laminate, in one embodiment, is between about <NUM> microns and about <NUM> microns. In one embodiment the coating thickness of the laminate is between about <NUM> microns and about <NUM> microns.

The abrasive elements comprise a make layer made from a curable composition (e.g., uncured or partially cured resin composition. In some instances, therefore, this specification makes reference to cured (e.g., cured resin composition) or uncured compositions (e.g., uncured or partially cured resin composition).

The nature of make layer comprising the uncured or partially cured resin composition that is converted to cured resin composition is non-limiting.

In preferred embodiments, the make layer precursor comprises a phenolic resin (e.g., PREFERE <NUM>5077A from Arclin, Mississauga, Ontario, Canada). 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 <NUM>: <NUM>. 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 <NUM> and <NUM>, thus presenting pendant methylol groups. Alkaline catalysts suitable for catalyzing the reaction between aldehyde and phenolic components of resole phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, and sodium carbonate, all as solutions of the catalyst dissolved in water.

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

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

The make layer precursor can comprise additional 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.

Examples of commercially available polyurethane dispersions include aqueous aliphatic polyurethane emulsions available as NEOREZ R-<NUM>, NEOREZ R-<NUM>, NEOREZ R-<NUM>, NEOREZ R-<NUM>, and NEOREZ R-<NUM> 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 <NUM>, SANCURE <NUM>, and SANCURE <NUM> from Lubrizol, Inc. of Cleveland, Ohio; an aqueous aliphatic self-crosslinking polyurethane dispersion available as TURBOSET <NUM> 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. Examples of additional suitable aqueous polyurethane dispersions are described in the specification of commonly-owned <CIT>.

The make layer can comprise a crosslinked binder composition and is typically prepared by at least partially curing a curable make layer precursor. In such embodiments, the make layer preferably comprises a photocured crosslinked acrylic polymer, although any crosslinked polymeric binder material can be used. Details concerning photocurable acrylic monomers can be found, for example, in commonly-owned <CIT>.

In some embodiments, the make layer may be a structured abrasive element comprising a plurality of shaped abrasive composites. Details concerning the molding and curing steps involved in making structured abrasive composites can be found, for example, in <CIT> (Pieper et al. ) and <CIT> (Woo et al.

The abrasive particles are dispersed throughout the make layer, or are partially embedded in the make layer.

Useful abrasive particles may be the result of a crushing operation (e.g., crushed abrasive particles that have been sorted for shape and size) or the result of a shaping operation (i.e., shaped abrasive particles) in which an abrasive precursor material is shaped (e.g., molded), dried, and converted to ceramic material. Combinations of abrasive particles resulting from crushing with abrasive particles resulting from a shaping operation may also be used. The abrasive particles may be in the form of, for example, individual particles, agglomerates, composite particles, and mixtures thereof.

The abrasive particles should have sufficient hardness and surface roughness to function as crushed abrasive particles in abrading processes. Preferably, the abrasive particles have a Mohs hardness of at least <NUM>, at least <NUM>, at least <NUM>, at least <NUM>, or even at least <NUM>.

Suitable abrasive particles include, for example, 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 <NUM> CERAMIC ABRASIVE GRAIN from <NUM> Company, St. Paul, Minnesota, brown aluminum oxide, blue aluminum oxide, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, garnet, titanium carbide, diamond, cubic boron nitride, 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. Examples of sol-gel-derived abrasive particles from which the abrasive particles can be isolated, and methods for their preparation can be found, in <CIT> (Leitheiser et al. ); <CIT> (Cottringer et al. ); <CIT> (Schwabel), <CIT> (Monroe et al. ); and <CIT> (Monroe et al. It is also contemplated that the abrasive particles could comprise abrasive agglomerates such, for example, as those described in <CIT>) or <CIT>). In some embodiments, 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. The abrasive particles may be treated before combining them with the binder, or they may be surface treated in situ by including a coupling agent to the binder.

Preferably, the abrasive particles (and especially the abrasive particles) comprise ceramic abrasive particles such as, for example, sol-gel-derived polycrystalline alpha alumina particles. Ceramic 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, <CIT>) and <CIT>) and <CIT>). Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, <CIT>); <CIT>); <CIT>); <CIT>); <CIT>); <CIT>); and <CIT>); and in <CIT>).

In some preferred embodiments, 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. Useful abrasive particles may be formed abrasive particles can be found in <CIT>); <CIT>(<CIT>)); and <CIT>). <CIT>) 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.

Formed abrasive particles also include shaped abrasive particles. 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. Shaped abrasive particle as used herein excludes randomly sized abrasive particles obtained by a mechanical crushing operation. Details concerning such abrasive particles and methods for their preparation can be found, for example, in <CIT>); <CIT>); <CIT>); <CIT>); and in <CIT>); <CIT>); <CIT>); and <CIT>). One particularly useful precisely-shaped abrasive particle shape is that of a platelet having three-sidewalls, any of which may be straight or concave, and which may be vertical or sloping with respect to the platelet base; for example, as set forth in the above cited references.

It is expressly contemplated that the method illustrated can be applied to other abrasive particles, such as platey, or partially shaped particles.

Surface coatings on the abrasive particles may be used to improve the adhesion between the abrasive particles and a binder material, or to aid in electrostatic deposition of the abrasive particles. In one embodiment, surface coatings as described in <CIT> (Celikkaya) in an amount of <NUM> to <NUM> percent surface coating to abrasive particle weight may be used. Such surface coatings are described in <CIT> (Celikkaya et al. ); <CIT> (Wald et al. ); <CIT>(Nicholson); <CIT> (Rowse et al. );<CIT> (Kunz et al. ); <CIT> (Martin et al. );<CIT> (Markhoff-Matheny et al. ); and <CIT> (Kunz et al. Additionally, the surface coating may prevent shaped abrasive particles from capping. Capping is the term to describe the phenomenon where metal particles from the workpiece being abraded become welded to the tops of the abrasive particles. Surface coatings to perform the above functions are known to those of skill in the art.

In some embodiments, the abrasive particles may be selected to have a length and/or width in a range of from <NUM> micrometers to <NUM> millimeters (mm), more typically <NUM> to <NUM>, and more typically <NUM> to <NUM>, although other lengths and widths may also be used.

The abrasive particles may be selected to have a thickness in a range of from <NUM> micrometer to <NUM>, more typically from <NUM> micrometer to <NUM>, although other thicknesses may be used. In some embodiments, abrasive particles may have an aspect ratio (length to thickness) of at least <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more.

Abrasive particles may be independently sized according to an abrasives industry recognized specified nominal grade. Exemplary abrasive industry recognized grading standards include those promulgated by ANSI (American National Standards Institute), FEPA (Federation of European Producers of Abrasives), and JIS (Japanese Industrial Standard). Such industry accepted grading standards include, for example: ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, ANSI <NUM>, and ANSI <NUM>; FEPA P8, FEPA P12, FEPA P16, FEPA P24, FEPA P30, FEPA P36, FEPA P40, FEPA P50, FEPA P60, FEPA P80, FEPA P100, FEPA P120, FEPA P150, FEPA P180, FEPA P220, FEPA P320, FEPA P400, FEPA P500, FEPA P600, FEPA P800, FEPA P1000, FEPA P1200; FEPA F8, FEPA F12, FEPA F16, and FEPA F24;. and JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, JIS <NUM>, and JIS <NUM>,<NUM>. More typically, the crushed aluminum oxide particles and the non-seeded sol-gel derived alumina-based abrasive particles are independently sized to ANSI <NUM> and <NUM>, or FEPA F36, F46, F54 and F60 or FEPA P60 and P80 grading standards.

Alternatively, the abrasive particles can be graded to a nominal screened grade using U. Standard Test Sieves conforming to ASTM E-<NUM> "Standard Specification for Wire Cloth and Sieves for Testing Purposes". ASTM E-<NUM> prescribes the requirements for the design and construction of testing sieves using a medium of woven wire cloth mounted in a frame for the classification of materials according to a designated particle size. A typical designation may be represented as -<NUM>+<NUM> meaning that the shaped abrasive particles pass through a test sieve meeting ASTM E-<NUM> specification for the number <NUM> sieve and are retained on a test sieve meeting ASTM E-<NUM> specification for the number <NUM> sieve. In one embodiment, the shaped abrasive particles have a particle size such that most of the particles pass through an <NUM>-mesh test sieve and can be retained on a <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> mesh test sieve. In various embodiments, the shaped abrasive particles can have a nominal screened grade comprising: <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, <NUM>+<NUM>, or <NUM>+<NUM>. Alternatively, a custom mesh size could be used such as <NUM>+<NUM>.

Abrasive agglomerate particles such as those described in the specification of commonly-owned <CIT> may be especially useful for making abrasive articles described herein. At least one dimension of the abrasive agglomerate particles can be greater than the gaps in porous substrates, ensuring that abrasive agglomerate particles do not fall through the pores on the porous substrates during the making process of the abrasive articles.

The abrasive particles <NUM> can optionally be oriented by influence of a magnetic field prior to the make layer precursor being cured. See, for example, commonly-owned <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

In some embodiments, the abrasive particles can optionally be placed using tools for controlled orientation and placement of abrasive particles. See, for example, commonly-owned <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, and <CIT>.

In embodiments shown in <FIG>, a size layer <NUM> comprising polymeric binder is disposed on at least a portion of, preferably at least substantially all of the make layer. While it is permissible for minimal amounts of the size layer to extend beyond the make layer, it is preferred that the size layer resides substantially completely on the make layer and abrasive particles.

The size layer can be prepared in the same manner from a size layer precursor comprising any of the foregoing curable materials in the make layer, which may be the same as or different from the size layer. In preferred embodiments the size layer comprises a cured phenolic resin; e.g., as described hereinabove. The size layer precursor may be applied to the make layer and cured to form the size layer by any suitable technique, including those used for applying and curing the make layer precursor.

In addition to other components, the make and size layers and their precursors may further contain optional additives, for example, to modify performance and/or appearance. Exemplary additives include grinding aids, fillers, plasticizers, wetting agents, surfactants, pigments, coupling agents, fibers, lubricants, thixotropic materials, antistatic agents, suspending agents, and/or dyes.

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. A combination of different grinding aids can be used. Exemplary antistatic agents include electrically conductive material such as vanadium pentoxide (e.g., dispersed in a sulfonated polyester), humectants, carbon black and/or graphite in a binder.

Examples of useful fillers for this disclosure include silica such as 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; carbon black; aluminum oxide; titanium dioxide; cryolite; chiolite; and metal sulfites such as calcium sulfite.

The abrasive article may optionally also include a supersize layer <NUM>. In general, the supersize layer is the outermost coating of the abrasive article and directly contacts the workpiece during an abrading operation. It may be disposed on the size layer, the make layer if there is no size layer, and uncoated portions of the porous substrate, for example. The optional supersize layer may serve to prevent or reduce the accumulation of swarf (the material abraded from a workpiece) between abrasive particles, which can dramatically reduce the cutting ability of the coated abrasive disc. Useful supersize layers typically include a grinding aid (e.g., potassium tetrafluoroborate), metal salts of fatty acids (e.g., zinc stearate or calcium stearate), salts of phosphate esters (e.g., potassium behenyl phosphate), phosphate esters, ureaformaldehyde resins, mineral oils, crosslinked silanes, crosslinked silicones, and/or fluorochemicals. Useful supersize materials are further described, for example, in <CIT>). Typically, the amount of grinding aid incorporated into coated abrasive articles is about <NUM> to about <NUM> gsm, more typically about <NUM> to about <NUM> gsm. The supersize may contain a binder such as for example, those used to prepare the size or make layer, but it need not have any binder.

In some embodiments, the abrasive articles can contain one or more fiber reinforcement materials. The use of a fiber reinforcement material can provide an abrasive element 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.

The one or more fiber reinforcements may comprise one or more fiber-containing 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 porous, such as a scrim.

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.

Further options and advantages of the fiber reinforcement materials are described in <CIT>).

Methods of making an abrasive article generally comprise joining a laminate to a porous substrate, joining a curable resin composition to the laminate opposite the porous substrate; and joining abrasive particles to the curable resin composition.

In a first step, a laminate is joined to a porous substrate comprising strands forming first void spaces between the strands (e.g., as described hereinabove). The laminate can be joined to the porous substrate by any suitable means, including by first applying a suitable adhesive layer (not shown) onto the substrate, followed by applying the laminate (e.g., by melting the laminate material onto the porous substrate; printing the laminate onto the porous substrate; or combinations of any of the foregoing methods for joining the laminate) to the porous substrate.

Several examples of applying the laminate to substrate using hot press lamination are shown in <FIG>. In these examples, although two polymers (i.e. 530A and 530B) are demonstrated as laminate materials <NUM>, it is to be understood that the laminate materials can be non-limiting, as described hereinabove. The starting laminate materials <NUM> could be in a form of nonwoven fibers (for example, <FIG>), pellet (for example, <FIG>), or films (<FIG>, details can be found in, for example, as described in commonly-owned <CIT>). After the hot press lamination on the substrate, a first portion <NUM> and a second portion <NUM> could be formed on the surface of the laminate. In some embodiments, at least one starting laminate material can comprise a structural pattern (for example, 503B in <FIG>), or at least one starting laminate material can be laminated with a predetermined pattern by using any suitable means of pattern coating, for example, with a screen or a stencil. This can result in lamination with patterns, i.e., the first portion <NUM> and the second portion <NUM> can be arrayed in at least one pattern on the laminate surface.

The laminate functions to, among other things, provide a substantially flat landing for uncured (or partially cured) resin composition, such that uncured resin composition that is deposited on the laminate remains on the surface and does not have an opportunity to, e.g., move into the spaces between strands of the porous substrate.

In a second step, uncured resin composition is joined to the laminate opposite the porous substrate. The uncured resin composition can be joined to the laminate by any suitable means; for example, by directly coating the uncured resin composition onto the laminate or by using combinations of two or more suitable methods (e.g., extrusion die coating, curtain coating, knife coating, gravure coating, and spray coating) for joining the uncured resin composition to the laminate opposite the porous substrate. In some embodiments, the uncured resin composition can be applied onto the laminate by using a (rotary) stencil/screen printing roll, or flatbed screen/stencil printing.

In various embodiments, an uncured make resin composition is liquid based. For example, the uncured make resin composition can be in a form of suspension, solution, or emulsion. When the uncured make resin composition is applied to the laminate, the uncured make resin composition have a tendency of migrating to the portions with relatively high surface free energy from the portions with relatively low surface free energy on the laminate surface. The rate of migrating may depend on the viscosity of the uncured make resin composition, and on the surface free energy on the laminate surface. An uncured make resin composition with a low viscosity may migrate to the portion with relatively high surface free energy less than seconds, while an uncured make resin composition with a higher viscosity may take longer time (e.g., seconds, minutes, or hours) to migrate to the portion with relatively high surface free energy. In preferred embodiments, an uncured make resin composition can form a plurality of discrete areas or interconnected sections on the laminate surface.

In some embodiments, an uncured make resin composition is aqueous based, and the laminate comprises hydrophobic and hydrophilic materials. After the aqueous uncured make resin composition is applied, it tends to shrink away from the hydrophobic surface potion and gather on the hydrophilic surface potion on the laminate surface to form a plurality of discrete areas or interconnected sections.

In a third step, abrasive particles are joined to the uncured resin composition by any suitable method, including drop, electrostatic, magnetic, and other mechanical methods of mineral coating. For example, abrasive particles can be deposited onto uncured resin composition by simply dropping the abrasive particles onto the uncured resin composition; by electrostatically depositing abrasive particles onto the uncured resin composition; or by using combinations of two or more suitable methods for joining the abrasive particles to the uncured resin composition. In some embodiments, the abrasive particles can optionally be oriented under the influence of a magnetic field, or with a placement tool, prior to the resin being cured, as earlier indicated.

In a fourth step, the uncured resin composition is cured, this way abrasive particles are at least partially embedded in the cured resin composition and are substantially permanently attached. Uncured resin composition can be cured to form cured resin by any applicable curing mechanism, including thermal cure, photochemical cure, moisture-cured or combinations of two or more curing mechanism. But if the uncured resin composition is cured by any means that does not include heating, a fifth step (not shown) may be necessary to effect migration of the laminate away from the void spaces between the strands.

During the curing process, at least a portion of the laminate that is not covered by cured resin composition migrates away from the first void spaces between the strands, thereby opening a plurality of the second void spaces extending through the laminate coinciding with the first void spaces. The laminate therefore avoids the first void spaces when the cured resin composition is absent above the first void spaces. Moreover, the laminate covers the first void spaces when the cured resin composition is above the first void spaces. The cured resin composition supports the laminate above the first void spaces.

<CIT>) and <CIT>) describes methods and materials for heating a laminate on a porous substrate to cause retraction and pore formation. Preferably, the melting temperature of the laminate is below the curing temperature of the make resin.

Methods by which the abrasive article is made are also contemplated where one or more of the steps described herein can be accomplished in a single step or wherein certain steps can be performed in an order different from described hereinabove. For example, uncured or partially cured resin composition could be joined/deposited to the laminate first to form a first composite. The first composite material comprising uncured or partially cured resin and the laminate could then be joined in a single step to the porous substrate, followed by Steps <NUM> and <NUM>. Alternatively, the laminate and uncured or partially cured resin composition could be co-deposited (e.g., co-extruded) onto porous substrate <NUM>, followed by Steps <NUM> and <NUM>.

In yet another alternative, abrasive particles can be joined with uncured or partially cured resin composition first to form a second composite. In this instance, uncured or partially cured resin composition could be joined/deposited on a removable liner first. The abrasive particles <NUM> could then be joined/deposited onto the uncured or partially cured resin composition to form the second composite. The second composite material comprising abrasive particles joined with uncured or partially cured resin composition could then be joined/deposited to laminate to make a third composite material. The third composite material comprising abrasive particles joined with uncured or partially cured resin composition, which is in turn joined to laminate, could then be joined in a single step to porous substrate, followed by Steps <NUM> and <NUM>. Examples of method of making abrasive articles can be further found in commonly-owned <CIT>, <CIT>, <CIT>, <CIT> <CIT>, <CIT>, <CIT>, <CIT> and <CIT>.

Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention, which is defined by the claims.

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. Unit Abbreviations used in the Examples: gsm = grams per square meter; cm = centimeter; µm = micrometer; °C = degree Celsius. Materials used in the Examples are described in Table <NUM>, below.

A backing MESH with a diameter of <NUM>,<NUM> (<NUM> inch) was placed on the hot-plate of a steam press (available as STEAMFAST Model SF-<NUM> from Vornado air, LLC, Andover, Kansas). PE-MELTY and PET-MELTY strips were randomly placed on non-loop side of the mesh backing to cover the surface of the mesh backing. PE-MELTY covered about <NUM>% of the surface, and PET-MELTY covered about <NUM>% of the surface. The weight of the PE-MELTY used in the example was about <NUM> gsm by calculation. The mesh backing together with the melty layer was pressed at <NUM> for about <NUM> seconds to laminate the melty layer onto the mesh backing. The sample was then cooled down to around <NUM>.

A piece of Laminated Substrate <NUM> was placed on a balance. Make resin MKR1 was applied onto the laminate with a putty knife with the target add-on of <NUM>-<NUM> grams per <NUM>,<NUM> square cm (<NUM> square inches). As MKR1 was applied, it immediately de-wetted on portions of the laminated surface and formed randomly distributed areas on the laminated backing, as shown in <FIG>.

The procedure described in Laminated Substrate <NUM> was generally repeated, except that PP-MELTY was used to cover about <NUM>% of the mesh surface, and PET-MELTY covered about <NUM>% of the surface. The hot-press was conducted at <NUM>. The weight of the PP-MELTY used in the example was about <NUM> gsm by calculation.

MKR1 was applied with a brush onto a <NUM>-inch (<NUM>-cm) diameter disc of Laminated Substrate <NUM>. About <NUM> P400 grade AO abrasive mineral was applied onto the mesh backing through drop coating. The disc was pre-cured at <NUM> for <NUM> hour and then cured at <NUM> for <NUM> hours. The mesh abrasive disc having randomly distributed abrasive areas is shown in <FIG>.

A backing MESH with a diameter of <NUM> inches (<NUM>) was placed on the hot-plate of a steam press (available as STEAMFAST Model SF-<NUM> from Vornado air, LLC, Andover, Kansas). PET-MELTY was placed on the top of the mesh backing to fully cover the surface of the mesh backing. A pre-pattern-cut PE-MELTY (with <NUM> × <NUM> square shaped opens) was placed on the top of the PET-MELTY, and the pre-pattern-cut PE-MELTY covered about <NUM>% of the surface of PET-MELTY. The sample was pressed at <NUM>-<NUM> for about <NUM> seconds to laminate the laminate layer onto MESH. The sample was then cooled down to about <NUM>.

MKR2 was applied onto the mesh backing with a brush with target add-on of <NUM> grams per <NUM>,<NUM> square cm (<NUM> square inches).

MKR2 de-wetted on PE-MELTY portion and gathered on the PET-MELTY portion on the laminate surface, forming make resin patterns. A blend of abrasive particles comprising <NUM> % P220 grade SAP and <NUM>% P220 grade AO particles (total mineral weight of <NUM> grams) was applied onto the mesh backing through drop coating. A top view of the resulting coated abrasive disc with patterned abrasive layers is shown as <FIG>.

Claim 1:
An abrasive article (<NUM>) comprising:
a substrate (<NUM>) comprising strands (<NUM>) forming first void spaces (<NUM>) between strands;
a laminate (<NUM>) joined to the substrate, wherein the laminate comprises a surface opposite to the substrate;
a resin composition (<NUM>) joined to the surface of the laminate, wherein a first portion (<NUM>) of the surface of the laminate has a first surface free energy, wherein a second portion (<NUM>) of the surface of the laminate has a second surface free energy, and wherein the first surface free energy is different from the second surface free energy; and
abrasive particles (<NUM>) joined to the resin composition, wherein
a plurality of second void spaces (<NUM>) extends through the laminate coinciding with first void spaces (<NUM>) in the porous substrate.