Abrasive article and method of making the same

Abstract

An abrasive article includes a porous substrate having openings extending through the porous substrate between opposing first and second major surfaces. An abrasive coating is disposed on only a portion of the first major surface of the porous substrate. The abrasive coating includes a functional layer disposed on only a portion of the first major surface of the porous substrate, a make layer disposed on at least a portion of the functional layer opposite the porous substrate, and abrasive particles. The functional layer and the make layer each include a chemically crosslinked binder. The functional layer completely plugs a first portion of the openings and incompletely plugs a second portion of the openings, which allows swarf being abraded to pass through the abrasive article. Methods of making the abrasive article are also disclosed.

Description

Background Technology

[0001] Coated abrasive articles have an abrasive layer fixed to a substrate. The substrate can be porous or non-porous. Examples of coated abrasive discs include sandpaper, abrasive pads, and abrasive belts.

[0002] Dry grinding operations commonly generate significant amounts of airborne dust. To minimize this airborne dust, it is known to use porous abrasive articles on the tool while simultaneously drawing a vacuum through the back of the article from the grinding side into a dust collection system. For this purpose, numerous thin-film-backed grinding discs with added perforations to facilitate vacuum dust removal are available.

[0003] As an alternative to converting the dust removal holes into the grinding disc, there are also commercial products in which an abrasive layer is coated onto a porous knitted fabric having loops integrally formed on one side as part of the porous knitted fabric. These loops are used as part of a hook-and-loop attachment system for attachment to power tools. Summary of the Invention

[0004] There has been a persistent need for a new coated abrasive product that offers enhanced cutting and / or life performance while exhibiting excellent dust removal capabilities.

[0005] This disclosure provides a combination of multiple benefits (combination of dust removal with cutting and / or service life) by patterning a functional layer onto a portion of the main surface of a porous substrate and then setting an abrasive layer on the patterned functional layer. Therefore, the patterned abrasive layer can be designed independently of any pattern present on the porous substrate to balance abrasive performance and dust removal.

[0006] In one aspect, this disclosure provides an abrasive article comprising:

[0007] A porous substrate having an opening extending through the porous substrate between opposing first and second main surfaces;

[0008] An abrasive coating is disposed on only a portion of a first primary surface of a porous substrate, wherein the abrasive coating comprises:

[0009] A functional layer disposed on only a portion of a first main surface of a porous substrate, wherein the functional layer contains a first chemically cross-linked adhesive, wherein the functional layer completely blocks a first portion of an opening and does not completely block a second portion of an opening;

[0010] A primer layer disposed on at least a portion of the functional layer opposite the porous substrate, wherein the primer layer comprises a second chemically cross-linked adhesive composition; and

[0011] Abrasive particles, which are dispersed in or at least partially embedded in the primer layer.

[0012] The second part of the opening allows the grinding debris to pass through the abrasive material.

[0013] In some embodiments, the abrasive article also includes a component of a two-piece hook-and-loop attachment system that is fixed to the porous substrate relative to the functional layer.

[0014] In another aspect, the present invention provides a method for preparing abrasive articles, the method comprising:

[0015] A porous substrate is provided having an opening extending through the porous substrate between opposing first and second main surfaces;

[0016] A crosslinkable functional layer precursor is disposed on a first main surface of a porous substrate, wherein the crosslinkable functional layer precursor completely blocks a first portion of the opening and does not completely block a second portion of the opening.

[0017] Crosslink the crosslinkable functional layer precursor to provide a crosslinked functional layer;

[0018] A curable primer precursor is disposed on at least a portion of a crosslinked functional layer opposite to a porous substrate, wherein the curable primer precursor has abrasive particles dispersed therein.

[0019] And at least partially cure the first curable adhesive composition,

[0020] The second part of the opening allows the grinding debris to pass through the abrasive material.

[0021] In another aspect, this disclosure provides a method for preparing abrasive articles, the method comprising:

[0022] A porous substrate is provided having an opening extending through the porous substrate between opposing first and second main surfaces;

[0023] A crosslinkable functional layer precursor is disposed on a first main surface of a porous substrate, wherein the crosslinkable functional layer precursor completely blocks a first portion of the opening and does not completely block a second portion of the opening.

[0024] Crosslink the crosslinkable functional layer precursor to provide a crosslinked functional layer;

[0025] A curable primer precursor is disposed on at least a portion of the crosslinked functional layer opposite the porous substrate;

[0026] The abrasive particles are partially embedded in a curable primer precursor;

[0027] The curable primer precursor is at least partially cured to provide the primer layer;

[0028] A curable adhesive precursor is disposed on at least a portion of the primer layer and the abrasive particles; and

[0029] At least partially cure the curable adhesive layer precursor to provide abrasive articles.

[0030] The second part of the opening allows the grinding debris to pass through the abrasive material.

[0031] The features and advantages of this disclosure will be further understood upon consideration of the specific embodiments and the appended claims. Attached Figure Description

[0032] Figure 1 This is a schematic perspective view of an exemplary abrasive article 100 according to the present disclosure.

[0033] Figure 1A It is a schematic cross-sectional side view of the abrasive product 100 taken along line 1A-1A.

[0034] Figure 2 This is a schematic perspective view of an exemplary abrasive article 100 according to the present disclosure.

[0035] Figure 2A It is a schematic cross-sectional side view of the abrasive product 200 taken along line 2A-2A.

[0036] Figure 3 This is a 50x optical micrograph of a portion of the non-circular side of the mesh substrate used in Example 1.

[0037] Figure 4 This is a 50x optical micrograph of the patterned edge portion of the patterned coating side of the patterned coated mesh substrate in Example 1.

[0038] Figure 5 This is a 50x optical micrograph of a portion of the coated side of the abrasive-coated mesh substrate in Example 1.

[0039] Figure 6 This is a 50x optical micrograph of a portion of the coated side of the abrasive article of Example 1.

[0040] It should be understood that those skilled in the art can devise many other modifications and embodiments that fall within the scope and spirit of the principles of this disclosure. The accompanying drawings may not be drawn to scale.

[0041] manual

[0042] exist Figure 1Exemplary embodiments of abrasive articles according to this disclosure are depicted. See now. Figure 1 An exemplary abrasive article 100 has a porous substrate 110 (shown as a mesh) having opposing first main surfaces 112 and second main surfaces 114. The first main surface 112 has an abrasive coating 116 disposed on only a portion of the porous substrate according to a predetermined pattern 125.

[0043] like Figure 1A As shown, the porous substrate 110 has a first portion 115a of openings that extend through the abrasive article and are completely blocked by the functional layer 118, thereby preventing dust from passing through these openings. For the second portion 115b of openings, these openings are not completely blocked, thus allowing dust to pass through. The abrasive coating includes the functional layer 118 and a primer layer 130 disposed on the functional layer. The primer layer 130 includes abrasive particles 140 dispersed in a crosslinked binder composition 135. An optional topcoat layer 150 covers the primer layer 130.

[0044] The optional attachment interface layer 160, fixed to the second primary surface of the porous substrate, includes one half of a two-piece mechanical fastening system, shown as an annular portion of a hook-and-loop fastening system. The optional attachment interface layer may include one half of any two-piece mechanical fastening system, including, for example, hook-and-loop fastening systems and mushroom stem web mechanical fasteners.

[0045] exist Figure 2 Exemplary embodiments of abrasive articles according to this disclosure are depicted. See now. Figure 2 An exemplary abrasive article 200 has a porous substrate 210 having opposing first main surfaces 212 and second main surfaces 214. The first main surface 212 has an abrasive coating 216 disposed on only a portion of the porous substrate according to a predetermined pattern 225.

[0046] like Figure 2A As shown, the porous substrate 210 has a first portion 215a of openings that extend through the abrasive article and are completely blocked by the functional layer 218, thereby preventing dust from passing through these openings. For the second portion 215b of openings, these openings are not completely blocked, thereby allowing dust to pass through these openings.

[0047] The abrasive coating 216 includes a functional layer 218 and a primer layer 230 disposed on the functional layer. Abrasive particles 240 are partially embedded in the primer layer 230. A topcoat layer 250 covers the primer layer 230 and the abrasive particles 240. An optional topcoat layer 260 covers the topcoat layer 250.

[0048] The optional attachment interface layer 270, which is fixed to the second primary surface of the porous substrate, includes one half of a two-piece mechanical fastening system, shown as the annular portion of a hook-and-loop fastening system.

[0049] Exemplary porous substrates include knitted fabrics (e.g., knitted fabrics having a volumetric porosity of at least 20%, 30%, 40%, 50%, 60%, or even 70%), mesh fabrics, woven meshes / screens (e.g., wire mesh or fiberglass mesh), porous nonwoven fabrics, monolithic meshes (e.g., monolithic continuous plastic screens), perforated polymer membranes, and perforated non-porous (e.g., sealing) fabrics. In some embodiments, the porous substrate may include a monolithic loop substrate, particularly in the case of knitted fabrics.

[0050] The porous fabric substrate can be made from any known fiber, whether natural, synthetic, or a blend of natural and synthetic fibers. Examples of usable fiber materials include fibers or yarns comprising polyester (e.g., polyethylene terephthalate), polyamide (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic acid, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymer, vinyl chloride-acrylonitrile copolymer, graphite, polyimide, silk, cotton, linen, jute, hemp, and / or rayon. Usable fibers can be natural materials or recycled or waste materials, for example, recovered from garment cutting, carpet manufacturing, fiber manufacturing, or textile processing. Usable fibers can be homogeneous or composite materials such as bicomponent fibers (e.g., co-spun sheath-core fibers). These fibers can be stretched and crimped, but can also be continuous filaments, such as those formed by extrusion processes.

[0051] Porous membrane substrates may include perforated polymer membranes, including, for example, polyesters (e.g., polyethylene terephthalate), polyamides (e.g., hexamethylene adipamide, polycaprolactam), polypropylene, acrylic acid, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, and / or vinyl chloride-acrylonitrile copolymers. Perforation can be provided, for example, by die punching, needle punching, knife cutting, laser perforation, and trimming as described in U.S. Patent Nos. 9,168,636 (Wald et al.) and 9,138,031 (Wood et al.). Perforation can also be provided by applying flames, heat sources, or pressurized fluids, for example, as described in U.S. Patent Application No. 2016 / 0009048A1 (Slama et al.) and U.S. Patent No. 7,037,100 (Strobel et al.).

[0052] Porous substrates can be rigid, semi-rigid, or flexible. A porous substrate has an opening extending through its body between two opposing main surfaces. The opening can be, for example, a perforation or space between fiber strands of a fabric.

[0053] The openings in the porous substrate should be of sufficient size, which may be identical or different, to allow dust generated during the grinding operation to be vacuum-drawn through the openings and removed from the surface of the workpiece being ground. In some embodiments, these openings are of sufficient size such that some or all of them allow dust particles with an average diameter less than or equal to 0.01 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.3 mm, 0.5 mm, 1 mm, or even 2 mm to pass through the porous backing.

[0054] The porous substrate may have a thickness of at least 0.02 mm, at least 0.03 mm, at least 0.05 mm, at least 0.07 mm, or even at least 0.1 mm, but this is not required. Similarly, the porous substrate may have a thickness of up to 5 mm, up to 4 mm, up to 2.5 mm, up to 1.5 mm, or up to 0.4 mm in any combination with the aforementioned lower limits, but this is not required.

[0055] Generally speaking, the strength of the porous substrate should be sufficient to resist tearing or other damage during the grinding process. The thickness and smoothness of the porous substrate should also be suitable for providing the desired thickness and smoothness of the abrasive article; for example, this depends on the intended application or use of the abrasive article.

[0056] The porous substrate can have any basis weight; for example, in the range of 25 g / m² to 1000 g / m², more typically in the range of 50 g / m² to 600 g / m², and even more typically in the range of 100 g / m² to 300 g / m². To promote adhesion of the functional layer to the porous substrate, one or more surfaces of the porous substrate can be modified by known methods, including corona discharge, ultraviolet light irradiation, electron beam irradiation, flame discharge, and / or texturing.

[0057] The functional layer is disposed on only a portion of the first primary surface of the porous substrate, thereby also allowing some of the openings in the porous substrate to allow dust to pass through the abrasive article during grinding. The functional layer includes a crosslinked binder, which is typically provided by curing a corresponding functional layer precursor comprising a curable (i.e., chemically crosslinkable) resin. Available binder precursors include thermosetting resins, moisture-curing resins, and radiation-curing resins, which can be cured, for example, by exposure to heat, moisture, and / or particulate or electromagnetic radiation. Sources of particulate and electromagnetic radiation may include electron beams and ultraviolet and / or visible light.

[0058] Examples of suitable curable resins that can be used in functional layer precursors include, for example, phenolic resins, urea-formaldehyde resins, amino plastic resins, urethane resins, melamine-formaldehyde resins, cyanate ester resins, isocyanurate ester resins, (meth)acrylate resins (e.g., (meth)acrylate-modified polyurethanes, (meth)acrylate-modified epoxy resins, olefinically unsaturated radical polymerizable compounds, amino plastic derivatives having α,β-unsaturated carbonyl side groups, isocyanurate derivatives having at least one acrylate side group, and isocyanate derivatives having at least one acrylate side group), vinyl ethers, epoxy resins, and combinations thereof. As used herein, the term "(meth)acryloyl" encompasses acryloyl or methacryloyl. In some embodiments, radiation-curable resins are preferred.

[0059] Phenolic resins possess good thermal properties, availability, and relatively low cost, and are easy to handle. There are two types of phenolic resins: soluble phenolic resins and linear phenolic resins. Soluble phenolic resins have a formaldehyde to phenol molar ratio greater than or equal to 1:1, typically ranging from 1.5:1.0 to 3.0:1.0. Linear phenolic resins have a formaldehyde to phenol molar ratio less than 1:1. Examples of commercially available phenolic resins include those with the following known trade names: DUREZ and VARCUM, from Occidental Chemicals Corp., Dallas, Texas; RESINOX, from Monsanto Co., Saint Louis, Missouri; and AEROFENE and AROOTAP, from Ashland Specialty Chemical Co., Dublin, Ohio.

[0060] (Meth)acrylated polyurethanes comprise di(meth)acrylates of hydroxyl-terminated NCO-chain-extended polyesters or polyethers. Examples of commercially available acrylated polyurethanes include those from Cytec Industries, West Paterson, New Jersey, as CMD 6600, CMD 8400, and CMD 8805.

[0061] (Meth)acrylated epoxy resins include di(meth)acrylates of epoxy resins, such as diacrylates of bisphenol A epoxy resins. Examples of commercially available acrylated epoxy resins include those that can be obtained from Cytec Industries, such as CMD 3500, CMD 3600, and CMD 3700.

[0062] Alkenyl-bonded unsaturated radical polymerizable compounds include monomeric and polymeric compounds containing carbon, hydrogen, and oxygen atoms, and optionally nitrogen and halogens. Oxygen or nitrogen atoms, or both, are typically present in ethers, esters, polyurethanes, amides, and urea groups. Alkenyl-bonded unsaturated radical polymerizable compounds typically have a molecular weight below about 4,000 g / mol and are generally esters produced by reacting compounds containing a single or multiple aliphatic hydroxyl groups with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid. Representative examples of (meth)acrylate resins include methyl methacrylate, ethyl methacrylate, styrene, divinylbenzene, vinyltoluene, ethylene glycol diacrylate, ethylene glycol methacrylate, hexanediol diacrylate, triethylene glycol diacrylate, trimethylolpropane triacrylate, glycerol triacrylate, pentaerythritol triacrylate, pentaerythritol methacrylate, pentaerythritol tetraacrylate, and pentaerythritol tetrastearate. Other olefinically unsaturated resins include monoallyl, polypropylene, and polymethylallyl esters and carboxylic amides, such as diallyl phthalate, diallyl adipate, and N,N-diallyl adipamide. Other nitrogen-containing compounds include tris(2-acryloyloxyethyl)isocyanurate, 1,3,5-tris(2-methacryloyloxyethyl)triazine, acrylamide, n-methacrylamide, N,N-dimethylacrylamide, n-vinylpyrrolidone, and n-vinylpiperidone.

[0063] Each molecule or oligomer of the available amino-based plastic resins has at least one α,β-unsaturated carbonyl side group. These unsaturated carbonyl groups can be acrylate, methacrylate, or acrylamide-type groups. Examples of such materials include N-hydroxymethylacrylamide, N,N'-oxydimethylbisacrylamide, ortho-acrylamide-methylated phenol and para-acrylamide-methylated phenol, acrylamide-methylated linear phenolic resins, and combinations thereof. These materials are further described in U.S. Patent Nos. 4,903,440 and 5,236,472 (both granted to Kirk et al.).

[0064] Isocyanurate derivatives having at least one acrylate side group and isocyanate derivatives having at least one acrylate side group are further described in U.S. Patent No. 4,652,274 (Boettcher et al.). An example of an isocyanurate material is a triacrylate of tris(hydroxyethyl)isocyanurate.

[0065] Epoxy resins have one or more epoxy groups and can be polymerized via ring-opening reactions of the epoxy groups. Such epoxy resins include monomeric epoxy resins and oligomeric epoxy resins. Examples of available epoxy resins include: 2,2-bis[4-(2,3-epoxypropoxy)-phenylpropane] (a diglycidyl ether of bisphenol) and materials obtained as EPON 828, EPON 1004, and EPON 1001F from Hexion Inc., Houston, Texas; and materials obtained as DER-331, DER-332, and DER-334 from Dow Chemical Co., Midland, Michigan. Other suitable epoxy resins include glycidyl ethers of linear phenolic resins commercially available from Dow Chemical Co., Ltd., as DEN-431 and DEN-428.

[0066] Epoxy resins can be polymerized via a cationic mechanism by adding a suitable cationic curing agent. The cationic curing agent generates an acid source to initiate the polymerization of the epoxy resin. These cationic curing agents may include salts having ononium cations and halogens containing complex anions of metals or metalloids. Other curing agents (e.g., amine curing agents and guanidines) used for epoxy and phenolic resins may also be used.

[0067] Other cationic curing agents include salts having organometallic complex cations and halogens containing metal or metalloid complex anions, which are further described in U.S. Patent No. 4,751,138 (Tumey et al.). Another example is organometallic salts and onium salts, which are described in U.S. Patent Nos. 4,985,340 (Palazzotto et al.), 5,086,086 (Brown-Wensley et al.), and 5,376,428 (Palazzotto et al.). Other cationic curing agents include ionic salts of organometallic complexes, wherein the metal is selected from elements of Groups IVB, VB, VIB, VIIB, and VIIIB of the periodic table as described in U.S. Patent No. 5,385,954 (Palazzotto et al.).

[0068] Examples of free radical thermal initiators include peroxides, such as benzoyl peroxide and azo compounds.

[0069] Compounds that generate free radical sources when exposed to photochemical electromagnetic radiation are commonly referred to as photoinitiators. Examples of photoinitiators include benzoin and its derivatives such as α-methylbenzoin; α-phenylbenzoin; α-allylbenzoin; α-benzylbenzoin; benzoin ethers such as benzoin dimethyl ketal (commercially available as IRGACURE 651 from BASF, Ludwigshafen, Germany), benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and its derivatives such as 2-hydroxy-2-methyl-1-phenyl-1-propanone (obtained as DAROCUR 1173 from BASF) and 1-hydroxycyclohexylphenyl ketone (e.g., obtained as IRGACURE 184 from BASF); 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholino)-1-propanone (e.g., obtained as IRGACURE 184 from BASF) 907 is obtained from BASF; 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-1-butanone (e.g., IRGACURE 369 is obtained from BASF). Other available photoinitiators include, for example: pivaloin ether, anethole ether, anthraquinones (e.g., anthraquinone, 2-ethylanthraquinone, 1-chloroanthraquinone, 1,4-dimethylanthraquinone, 1-methoxyanthraquinone, or benzoanthraquinone), halomethyltriazines, benzophenone and its derivatives, iodonium salts and sulfonium salts, titanium complexes such as bis(n5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrolo-1-yl)phenyl]titanium (e.g., obtained from BASF as CGI 784DC); halomethylnitrobenzene (e.g., 4-bromomethylnitrobenzene), monoacylphosphine and diacylphosphine (e.g., all obtained from BASF as IRGACURE 1700, IRGACURE 1800, IRGACURE 1850 and DAROCUR 4265)). Combinations of photoinitiators can be used. One or more spectral sensitizers (e.g., dyes) can be used with the photoinitiator, for example, to improve the sensitivity of the photoinitiator to a specific photochemical radiation source.

[0070] To ensure crosslinking / curing of the curable resin, it should generally contain at least one polymerizable monomer having at least two, three, or even four polymerizable groups, but post-treatment (e.g., using ionizing radiation) can also effectively induce crosslinking.

[0071] The aforementioned curable resin may be combined with one or more of a catalyst, initiator (e.g., a free radical thermal initiator or a free radical photoinitiator), synergist, sensitizer, filler, coupling agent, colorant, or antioxidant. The amount and selection of any catalyst and / or initiator will vary depending on the curable resin selected and are within the capabilities of those skilled in the art. Typically, an amount of less than or equal to 10% by weight, preferably 5% by weight or less, is sufficient to achieve curing of the curable resin to a degree sufficient to provide a functional layer.

[0072] Thermocuring can be achieved by heating or exposure to radio frequency or infrared radiation, while photocuring can be achieved, for example, by exposure to photochemical radiation (e.g., visible light and / or ultraviolet electromagnetic radiation).

[0073] The functional layer and functional layer precursors can be modified by various additives, including, for example: surfactants (e.g., defoamers such as ethoxylated nonionic surfactants such as DYNOL 604), pigments (e.g., carbon black pigments such as C-SERIES BLACK 7LCD4115), fillers (e.g., silica such as CABOSIL M5), synthetic waxes (e.g., synthetic paraffin MP22), stabilizers, plasticizers, tackifiers, flow control agents, curing rate retarders, adhesion promoters (e.g., silanes such as (3-epoxypropoxypropyl)trimethoxysilane (GPTMS) and titanates), additives, impact modifiers, rheology modifiers, expanded microspheres, thermally conductive particles, electrically conductive particles, fillers such as silica, glass, clay, talc, colorants, glass beads and / or bubbles, and antioxidants.

[0074] The functional layer can be prepared by patterning a functional layer precursor onto a porous substrate and then curing it. Available patterning methods include, for example, gravure roll coating, spray coating, flexographic printing, jet printing, stencil printing, slot coating, and inkjet printing. Alternatively, the functional layer can be prepared by patterning a functional layer precursor onto a spacer sheet, covering it with a porous substrate, at least partially curing the precursor, and then removing the spacer sheet.

[0075] Preferably, the functional layer precursor is viscous enough during the patterning coating process to block the openings it coats without significant penetration, at least until it is cured. However, lower viscous formulations that penetrate the openings and thus block them can also be used.

[0076] In some implementations, the thickness of the functional layer can be from 5 micrometers to 200 micrometers, preferably from 20 micrometers to 200 micrometers; however, this is not required.

[0077] Functional layers can be randomly or arranged on a porous substrate according to a predetermined pattern (e.g., dots, grids, stripes, and / or wavy stripes). The pattern can be adjacent or non-adjacent.

[0078] The primer layer, comprising a cross-linked polymer material, is disposed on at least a portion of the functional layer opposite the porous substrate, preferably at least substantially all of it.

[0079] exist Figure 1 and Figure 1A In the illustrated embodiment, the abrasive particles are dispersed throughout the base coat. Figure 2 and Figure 2A In the embodiment shown, the abrasive particles are partially embedded in the base coat.

[0080] The primer layer comprises a first crosslinked adhesive composition and is typically prepared by at least partially curing a curable primer layer precursor, which may be the same as or different from the functional layer precursor.

[0081] In a preferred embodiment, the primer precursor comprises a phenolic resin (e.g., PREFERE 80 5077A from Arclin, Mississauga, Ontario, Canada). Suitable phenolic resins are typically formed by the condensation of phenol or alkylated phenol (e.g., cresol) and formaldehyde, and are generally classified as methyl phenolic resins or linear phenolic resins. Phenolic varnishes use acid-catalyzed phenolic resins with a formaldehyde to phenol molar ratio of less than 1:1. Resole / resol phenolic resins can be catalyzed with a basic catalyst, and the formaldehyde to phenol molar ratio is greater than or equal to one, typically between 1.0 and 3.0, thus exhibiting hydroxymethyl side groups. Suitable basic catalysts for catalyzing the reaction between the aldehyde and phenolic components of resole / resol phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines, and sodium carbonate, all as catalyst solutions dissolved in water.

[0082] Acetylated phenolic resins are typically coated as solutions containing water and / or organic solvents (e.g., alcohols). Typically, the solution contains solids of about 70% to about 85% by weight, but other concentrations can be used. If the solids content is very low, more energy is required to remove the water and / or solvent. If the solids content is very high, the resulting phenolic resin has excessively high viscosity, which often leads to processing problems.

[0083] Phenolic resins are well known and readily available from commercial sources. Examples of commercially available methyl phenolic resins that can be used to implement this disclosure include those sold by Durez Corporation under the trade name VARCUM (e.g., 29217, 29306, 29318, 29338, 29353); those sold by Ashland Chemical Co., Bartow, Florida under the trade name AEROFENE (e.g., AEROFENE 295); and those sold by Kangnam Chemical Company Ltd. of Seoul, South Korea under the trade name PHENOLITE (e.g., PHENOLITE TD-2207).

[0084] The primer precursor may include additional components, including polyurethane dispersions such as aliphatic and / or aromatic polyurethane dispersions. For example, the polyurethane dispersion may comprise polycarbonate polyurethane, polyester polyurethane, or polyether polyurethane. The polyurethane may include homopolymers or copolymers.

[0085] Examples of commercially available polyurethane dispersions include aqueous aliphatic polyurethane emulsions from DSM Neo Resins, Inc., Wilmington, Massachusetts, namely NEOREZ R-960, NEOREZ R-966, NEOREZ R-967, NEOREZ R-9036, and NEOREZ R-9699; aqueous anionic polyurethane dispersions from Essential Industries, Inc., Merton, Wisconsin, namely ESSENTIAL CC4520, ESSENTIAL CC4560, ESSENTIAL R4100, and ESSENTIAL R4188; and aqueous anionic polyurethane dispersions from SANCURE 843, SANCURE 898, and SANCURE 899. 12929 was a polyester-type polyurethane dispersion purchased from Lubrizol, Inc. (Cleveland, Ohio); TURBOSET 2025 was a waterborne aliphatic self-crosslinking polyurethane dispersion purchased from Lubrizol, Inc.; and BAYHYDROL PR240 was a co-solvent-free waterborne anionic aliphatic self-crosslinking polyurethane dispersion purchased from Bayer Material Science, LLC (Pittsburgh, Pennsylvania).

[0086] Additional suitable commercially available aqueous polyurethane dispersions include:

[0087] 1) Alberdingk U 6150, a solvent-free aliphatic polycarbonate polyurethane dispersion, purchased from Alberdingk Boley GmbH, Krefeld, Germany, has a viscosity of 50 mPa·s-500 mPa·s (according to ISO 1652, Brookfield RVT mandrel 1 / rpm 20 / factor 5), an elongation at break of approximately 200%, and a Koenig hardness of approximately 65s-70s after curing;

[0088] 2) Alberdingk U 6800, an aqueous, solvent-free, colloidal low-viscosity dispersion of aliphatic polycarbonate polyurethane without free isocyanate groups, purchased from Alberdingk Boley GmbH, Krefeld, Germany, has a viscosity of approximately 20 mPa·s-200 mPa·s (according to ISO 2555, Brookfield RVT mandrel 1 / rpm 50 / factor 2), an elongation at break of approximately 500%, and a Koenig hardness of approximately 45s after curing;

[0089] 3) Alberdingk U 6100, an aqueous, colloidal, anionic, low-viscosity dispersion of aliphatic polyester-polyurethane without free isocyanate groups, purchased from Alberdingk Boley GmbH, Krefeld, Germany, has a viscosity of approximately 20 mPa·s-200 mPa·s (according to ISO 1652, Brookfield RVT mandrel 1 / rpm 50 / factor 2), an elongation at break of approximately 300%, and a Koenig hardness of approximately 50s after curing;

[0090] 4) Alberdingk U9800, a solvent-free aliphatic polyester polyurethane dispersion, purchased from Alberdingk Boley GmbH, Krefeld, Germany, has a viscosity of approximately 20 mPa·s-200 mPa·s (according to ISO 1652, Brookfield RVT mandrel 1 / rpm 20 / factor 5), and an elongation at break of approximately 20%-50% and a Koenig hardness of approximately 100s-130s after curing; and

[0091] 5) Adiprene BL16 - a liquid polyurethane elastomer with capped isocyanate curing sites, purchased from Chemtura, Middlebury, Connecticut.

[0092] Optional additives (including rheology modifiers, defoamers, water-based latexes, and crosslinking agents) for use in polyurethane dispersions and, generally, for curable compositions, for use in curable compositions, can be added to the aqueous polyurethane dispersion. Suitable crosslinking agents include, for example, polyfunctional aziridines, methoxymethylated melamine, urea resins, carbodiimides, polyisocyanates, and capped isocyanates. Additional water may also be added to dilute the aqueous polyurethane dispersion, phenolic resin, or a combination thereof. The curable composition may be made, for example, from the aqueous polyurethane dispersion and the water-based latex.

[0093] The aqueous polyurethane dispersion may contain less than 20%, less than 10%, less than 5%, or less than 2% organic solvent. In specific embodiments, the aqueous polyurethane dispersion is substantially free of organic solvent. In some embodiments, the aqueous polyurethane dispersion has been found to contain at least about 7%, 15%, or 20% solids, and no more than about 50% or 60% solids. The aqueous polyurethane dispersion may contain no more than about 80%, 85%, or 93% water.

[0094] In some embodiments, it has been found that, when measured according to ASTM 4366-16, the aqueous polyurethane dispersion forms a film with a Koenig hardness of at least about 30 seconds and no more than about 200 seconds. Furthermore, in some embodiments, it has been found that the surface tension of the aqueous polyurethane dispersion can be at least about 50% and no more than about 300% of the surface tension of water. And in some embodiments, the aqueous polyurethane dispersion can have a viscosity of at least about 10 mPa⁻¹ to no more than about 600 mPa⁻¹, or at least about 70%, 80%, or 90% of the viscosity of water and no more than about 600%, 500%, or 400% of the viscosity of water.

[0095] Furthermore, in some embodiments, the aqueous polyurethane dispersion may contain at least about 100 parts per million parts (ppm), 1000 ppm, or even at least about 10000 ppm of dimethylolpropionic acid. For example, optional additives (including rheological modifiers, defoamers, and crosslinking agents) may be added to the aqueous polyurethane dispersion. Suitable crosslinking agents include, for example, polyfunctional aziridine, methoxymethylated melamine, urea resins, carbodiimides, polyisocyanates, and capped isocyanates. Additional water may be added to reduce the viscosity of the aqueous polyurethane dispersion. Similarly, adding up to 10% by weight of an 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 the components.

[0096] Dispersed polyurethane may contain at least one polycarbonate segment, but this is not a necessary condition.

[0097] The phenolic resin and aqueous polyurethane dispersion components are mixed at a solid weight ratio of 91% to 99% by weight of phenolic resin and 9% to 1% by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed at a solid weight ratio of 56% to 91% by weight of phenolic resin and 44% to 9% by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed at a solid weight ratio of 62% to 91% by weight of phenolic resin and 38% to 9% by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed at a solid weight ratio of 69% to 91% by weight of phenolic resin and 31% to 9% by weight of polyurethane. In some embodiments, the phenolic resin and aqueous polyurethane dispersion components are mixed at a solid weight ratio of 56% to 83% by weight of phenolic resin and 44% to 17% by weight of polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed at a solid weight ratio of 56% to 76% by weight of phenolic resin to 44% to 24% by weight of polyurethane. In some embodiments, the phenolic resin and the aqueous polyurethane dispersion component are mixed at a solid weight ratio of 56% to 69% by weight of phenolic resin to 44% to 31% by weight of polyurethane.

[0098] exist Figure 1 In some embodiments of the type shown, the primer layer may be a structured abrasive layer comprising multiple shaped (e.g., precision-shaped) abrasive compounds. In such embodiments, the primer layer preferably comprises a photocurable crosslinked acrylic polymer, but any crosslinked polymer binder material may be used. Details regarding photocurable acrylic monomers have been discussed above. Details regarding the molding and curing steps involved in preparing the structured abrasive compound can be found, for example, in U.S. Patent No. 5,152,917 (Pieper et al.) and U.S. Patent Application Publication No. 2011 / 0065362A1 (Woo et al.).

[0099] The abrasive particles available can be the result of a pulverizing operation (e.g., pulverized abrasive particles already classified according to shape and size) or a forming operation (i.e., shaped abrasive particles), wherein the abrasive precursor material is shaped (e.g., molded), dried, and transformed into a ceramic material. A combination of pulverized abrasive particles and forming abrasive particles can also be used. Abrasive particles can be in the form of, for example, single particles, agglomerates, composite particles, and mixtures thereof.

[0100] The abrasive particles should have sufficient hardness and surface roughness to function as pulverizing abrasive particles in the grinding process. Preferably, the abrasive particles have a Mohs hardness of at least 4, at least 5, at least 6, at least 7, or even at least 8.

[0101] Suitable abrasive particles include, for example, pulverized abrasive particles comprising: molten alumina, heat-treated alumina, white molten alumina, ceramic alumina materials (such as ceramic alumina materials commercially available from 3M Company, St. Paul, Minnesota as 3M CERAMIC ABRASIVE GRAIN), brown alumina, blue alumina, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, garnet, titanium carbide, diamond, cubic boron nitride, garnet, molten alumina-zirconia, iron oxide, chromium oxide, zirconium oxide, titanium dioxide, tin oxide, quartz, feldspar, flint, corundum, ceramics prepared by the sol-gel method (e.g., α-alumina), and combinations thereof. Examples of sol-gel derived abrasive particles from which abrasive particles can be separated, and methods for their 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 envisioned that the abrasive particles may comprise abrasive agglomerates, such as those described in U.S. Patent Nos. 4,652,275 (Bloecher et al.) or 4,799,939 (Bloecher et al.). In some embodiments, the abrasive particles may be surface-treated with a coupling agent (e.g., an organosilane coupling agent) or otherwise physically treated (e.g., iron oxide or titanium oxide) to enhance the adhesion of the pulverized abrasive particles to the binder. The abrasive particles may be treated prior to their bonding with the binder, or they may be surface-treated in situ by incorporating the coupling agent into the binder.

[0102] Preferably, the abrasive particles (and especially abrasive particles) comprise ceramic abrasive particles, such as polycrystalline α-alumina particles prepared, for example, by a sol-gel method. Ceramic pulverizing abrasive particles composed of microcrystals of α-alumina, magnesium aluminum spinel, and rare earth hexaaluminates can be prepared using sol-gel α-alumina particle precursors according to methods described, for example, in U.S. Patent No. 5,213,591 (Celikkaya et al.) and U.S. Publication Patent Applications 2009 / 0165394A1 (Culler et al.) and 2009 / 0169816A1 (Erickson et al.). Further details regarding methods for manufacturing abrasive particles derived from the sol-gel process can be found in, for example, U.S. Patents 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.), as well as U.S. Publication Patent Application 2009 / 0165394A1 (Culler et al.).

[0103] In some preferred embodiments, the available abrasive particles (particularly in the case of abrasive particles) can be shaped abrasive particles, as seen in U.S. Patent Nos. 5,201,916 (Berg), 5,366,523 (Rowenhorst (Re 35,570)), and 5,984,988 (Berg). U.S. Patent No. 8,034,137 (Erickson et al.) describes alumina abrasive particles that have been shaped to a specific form and then pulverized to form fragments that retain a portion of their initial shape characteristics. In some embodiments, the abrasive particles are precisely shaped (i.e., the shape of the particles is at least partially determined by the shape of the cavity in the production tool used to prepare them). Details regarding such 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.), 8,142,532B2 (Erickson et al.), and 9,771,504 (Adefris); and U.S. Patent Application Publications 2012 / 0227333 (Adefris et al.), 2013 / 0040537 (Schwabel et al.), and 2013 / 0125477 (Adefris). A particularly useful, precisely shaped abrasive particle is a lamellar shape with three sidewalls, any one of which can be straight or concave, and can be perpendicular or inclined relative to the lamellar base; for example, shapes described in the references cited above.

[0104] Surface coatings on abrasive particles can be used to improve adhesion between the abrasive particles and the binder material, or to facilitate electrostatic deposition of the abrasive particles. In one embodiment, the surface coating described in U.S. Patent No. 5,352,254 (Celikkaya) may be used in an amount of 0.1% to 2% of the weight of the abrasive particles. Such surface coatings are described in U.S. Patent Nos. 5,213,591 (Celikkaya et al.); 5,011,508 (Wald et al.); 1,910,444 (Nicholson); 3,041,156 (Rowse et al.); 5,009,675 (Kunz et al.); 5,085,671 (Martin et al.); 4,997,461 (Markhoff-Matheny et al.); and 5,042,991 (Kunz et al.). Additionally, the surface coating can prevent the shaped abrasive particles from being capped. "Capping" is a term used to describe the phenomenon where metal particles from a workpiece being ground are welded to the top of the abrasive grains. Surface coatings that perform the above function are known to those skilled in the art.

[0105] In some implementations, the length and / or width of the abrasive particles may be selected to be in the range of 0.1 micrometers to 3.5 millimeters (mm), more typically in the range of 0.05 mm to 3.0 mm, and more typically in the range of 0.1 mm to 2.6 mm, but other lengths and widths may also be used.

[0106] Abrasive particles with a thickness ranging from 0.1 micrometers to 1.6 millimeters, and more typically from 1 micrometer to 1.2 millimeters, can be selected, but other thicknesses are also possible. In some embodiments, the abrasive particles may have an aspect ratio (the ratio of length to thickness) of at least 2, 3, 4, 5, 6, or greater.

[0107] Abrasive particles can be independently classified by size according to industry-recognized grading standards. Exemplary industry-recognized grading standards include those issued by ANSI (American National Standards Institute), FEPA (Federation of European Abrasive Manufacturers), and JIS (Japanese Industrial Standards). Such industry-accepted grading standards include, for example: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 30, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400, and ANSI 600; 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, and FEPA P150. P320, FEPA P400, FEPA P500, FEPA P600, FEPA P800, FEPA P1000, FEPA P1200; FEPA F8, FEPA F12, FEPA F16 and FEPA F24; and JIS 8, JIS 12, JIS 16, JIS 24, JIS 36, JIS 46, JIS 54, JIS 60. JIS 80, JIS 100, JIS 150, JIS 180, JIS 220, JIS 240, JIS 280, JIS 320, JIS 360, JIS 400, JIS 600, JIS 800, JIS 1000, JIS 1500, JIS 2500, JIS 4000, JIS6000, JIS 8000 and JIS 10,000. More typically, the size of pulverized alumina particles and alumina-based abrasive particles prepared by seedless sol-gel methods are independently set to ANSI 60 and 80 or FEPA F36, F46, F54 and F60 or FEPA P60 and P80 grading standards.

[0108] Alternatively, abrasive particles can be classified into nominal sieve sizes using American standard test sieves conforming to ASTM E-11, "Standard Specification for Wire Cloth and Sieves for Testing Purposes." ASTM E-11 specifies the design and construction requirements for test sieves that use a medium of woven wire mesh mounted in a frame to classify materials according to a specified particle size. Typical designations can be -18 or +20, meaning that shaped abrasive particles can pass through an ASTM E-11 18-mesh test sieve but may remain on an ASTM E-11 20-mesh test sieve. In one embodiment, the shaped abrasive particles have a particle size such that most particles pass through an 18-mesh test sieve and may remain on 20, 25, 30, 35, 40, 45, or 50-mesh test sieves. In various implementation schemes, the shaped abrasive articles may have the following nominal sieve grades, including: -18+20, -20+25, -25+30, -30+35, -35+40, -40+45, -45+50, -50+60, -60+70, -70+80, -80+100, -100+120, -120+140, -140+170, -170+200, -200+230, -230+270, -270+325, -325+400, -400+450, -450+500, or -500+635. Alternatively, custom mesh sizes such as -90+100 may be used.

[0109] Prior to the curing of the primer precursor, the abrasive particles may optionally be oriented by the influence of a magnetic field. See, for example, the jointly owned PCT publications WO 2018 / 080703, WO 2018 / 080756, WO 2018 / 080704, WO 2018 / 080705, WO2018 / 080765, WO 2018 / 080784, WO 2018 / 136271, WO 2018 / 134732, WO 2018 / 080755, WO2018 / 080799, WO 2018 / 136269 and WO 2018 / 136268.

[0110] In some implementations, the abrasive particles may optionally be placed using tools for controlled orientation and placement of the abrasive particles. See, for example, the commonly owned PCT publications WO 2012 / 112305, WO 2015 / 100020, WO 2015 / 100220, WO 2015 / 100018, WO 2016 / 028683, WO 2016 / 089675, WO 2018 / 063962, WO 2018 / 063960、WO 2018 / 063958、WO 2019 / 102312、WO 2019 / 102328、WO 2019 / 102329、WO 2019 / 102330、WO 2019 / 102331、WO 2019 / 102332、WO 2016 / 205133、WO 2016 / 205267、WO 2017 / 007714、WO 2017 / 007703、WO 2018 / 118690、WO 2018 / 118699、WO U.S. Patent Publication 2018 / 118688, U.S. Patent Publication 2019 / 0275641, and U.S. Provisional Patent Applications 62 / 751097, 62 / 767853, 62 / 767888, 62 / 780987, 62 / 780988, 62 / 780994, 62 / 780998, 62 / 781009, 62 / 781021, 62 / 781037, 62 / 781043, 62 / 781057, 62 / 781072, 62 / 781077, 62 / 781082, 62 / 825938, and 62 / 781103.

[0111] exist Figure 2 and Figure 2A In the illustrated embodiment, a re-adhesive layer comprising a crosslinked polymer binder is disposed on at least a portion of the primer layer opposite the functional layer, preferably at least substantially all of it. While a minimum amount of the re-adhesive layer is permitted to extend beyond the primer layer, it is preferred that the re-adhesive layer reside substantially entirely on the primer layer and the abrasive particles.

[0112] The re-adhesive layer can be prepared in the same manner from a re-adhesive layer precursor, which includes any of the aforementioned curable materials in the primer layer and / or functional layer, which may be the same as or different from the re-adhesive layer. In a preferred embodiment, the re-adhesive layer comprises a cured phenolic resin; for example, as described above. The re-adhesive layer precursor can be applied to the primer layer and cured to form the re-adhesive layer by any suitable technique, including those used for applying and curing the primer layer precursor and / or functional layer precursor.

[0113] In addition to other components, the base coat and top coat, as well as their precursors, may also contain optional additives to, for example, modify properties 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.

[0114] Exemplary grinding aids can be organic or inorganic, including waxes, halogenated organic compounds such as chlorinated waxes like tetrachlorinated naphthalene, pentachlorinated naphthalene, and polyvinyl chloride; halide salts such as sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluoride, 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, organosulfur compounds, graphite, and metal sulfides. Combinations of different grinding aids can be used. Exemplary antistatic agents include conductive materials such as vanadium pentoxide (e.g., dispersed in sulfonated polyester), wetting agents, carbon black and / or graphite in a binder.

[0115] Examples of fillers that can be used in this disclosure include silica, such as quartz, glass beads, glass bulbs and glass fibers; silicates, such as talc, clay, (montmorillonite) feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate; metal sulfates (such as calcium sulfate, barium sulfate, sodium sulfate, sodium aluminum sulfate, aluminum sulfate); gypsum; vermiculite; wood flour; aluminum trihydrate; carbon black; alumina; titanium dioxide; cryolite; cone cryolite; and metal sulfites (such as calcium sulfite).

[0116] Abrasive articles may optionally include a top coat. Generally, the top coat is the outermost coating of the abrasive article and comes into direct contact with the workpiece during the grinding operation. For example, it may be applied over a top coat, or over a base coat if no top coat is available, and on uncoated portions of a porous substrate. The optional top coat can prevent or reduce the accumulation of dust (material ground off the workpiece) between abrasive particles, which can significantly reduce the cutting ability of the coated grinding disc. Suitable top coats typically include grinding aids (e.g., potassium tetrafluoroborate), metal salts of fatty acids (e.g., zinc stearate or calcium stearate), salts of phosphate esters (e.g., potassium dodecyl phosphate), phosphate esters, urea-formaldehyde resins, mineral oils, crosslinked silanes, crosslinked silicones, and / or fluorinated compounds. Suitable top coat materials are further described, for example, in U.S. Patent No. 5,556,437 (Lee et al.). Typically, the amount of grinding aid incorporated into coated abrasive articles is from about 50 gsm to about 400 gsm, and more commonly from about 80 gsm to about 300 gsm. The topcoat may contain binders, such as those used to prepare the topcoat or basecoat, but it need not have any binders.

[0117] To facilitate good dust removal, the abrasive article according to this disclosure allows airflow to pass through the abrasive article at a rate of, for example, at least 0.1 L / s (e.g., at least 0.2 L / s, at least 0.4 L / s, at least 0.6 L / s, at least 1 L / s; or about 0.1 L / s to about 1 L / s, about 0.25 L / s to about 0.75 L / s, about 0.5 L / s to about 1 L / s, about 1 L / s to about 2 L / s, about 1.5 L / s, or about 3 L / s), such that when in use and attached to a vacuum source (e.g., less than or equal to 40 Torr (5.3 kPa)), dust can be removed from the grinding surface through the abrasive article.

[0118] The objects and advantages of this disclosure are further illustrated by the following non-limiting embodiments, but the specific materials and quantities referenced in these embodiments, as well as other conditions and details, should not be regarded as undue limitations on this disclosure. Example

[0119] The object and advantages of this disclosure are further illustrated by the following non-limiting examples. The specific materials and quantities mentioned in these embodiments, as well as other conditions and details, should not be construed as undue limitation of the invention. Unless otherwise specified, all parts, percentages, ratios, etc., in the examples and the remainder of this specification are by weight.

[0120] Example 1

[0121] A 50cm × 30cm template of a 5-mil (127 μm) thick polyester film was prepared, featuring a continuous wavy pattern 3 mm wide, 4 mm spaced, 21 mm wavelength, and 4.9 mm amplitude. The wavy pattern was cut into the polyester film using a VLS675W CO2 laser (available from Universal Laser Systems Inc., Scottsdale, Arizona). The template was secured to the top of a release liner (commercially available as Silicon Secondary Release Liner 4999 from 3M Company, Saint Paul, Minnesota) by gluing the top ends together. A chemically crosslinkable functional layer composition was prepared by mixing the components shown in Table 1 below at room temperature for 5 minutes using a spatula in a black 16 oz (0.48 L) container.

[0122] Table 1

[0123]

[0124] Apply the composition to the top of the stencil and force it through by hand using a polyurethane rubber scraper. Remove the stencil, leaving a wavy pattern coating of the functional layer composition on the release liner. Then, cover the patterned coating with a non-circular side of a mesh substrate (GR150 H100 polyester / polyamide mesh backing, Net Mesh from SitiP (SitiP, SpA, Cene, Italy)) to form the laminate. Cur the laminate by passing it once through a UV processor (American Ultraviolet Company, Murray Hill, New Jersey) using two V-bulbs at 400 watts / inch sequentially. 2 (157.5W / cm 2 The process was carried out at a web speed of 30 ft / min (9.1 m / min) with a distance of 2 inches (5.1 cm) between the bulb and the laminate. The spacer was then removed to obtain a patterned coated mesh substrate.

[0125] The coating composition was prepared by mixing the components shown in Table 2 in a 16-ounce (0.48-liter) container with a spatula at room temperature for 5 minutes, followed by adding water to achieve a viscosity of approximately 2200 centipoise (mPa·s).

[0126] Table 2

[0127]

[0128] A coating composition is applied to a patterned stencil substrate using a 2-roll coater at a speed of approximately 9 m / min via a coincident coating operation. In the coincident coating operation, the patterned stencil substrate is passed through the roll gap between a steel top roller (pressed against the uncoated side of the patterned stencil substrate) and a silane rubber bottom roller with a Shore A hardness of 30 (partially immersed in the coating composition in an immersion pan). An excess coating composition is removed from the bottom roller using a doctor blade before contact with the patterned stencil substrate. This coincident coating operation produces a primer-coated stencil substrate.

[0129] The 80+ mineral blend was prepared by blending 90 wt% P80 (80 grade alumina mineral, traded under the name "BFRPL" from Treibacher Industrie AG, Althofen, Austria) with 10 wt% 80+ precision-formed particulate mineral (Cubitron II from 3M). The 80+ mineral blend was uniformly spread on a 14-inch × 20-inch (35.6 cm × 50.8 cm) plastic mineral tray to form a mineral bed. The mineral tray was inserted into the positive terminal of the DC power supply of an electrostatic mineral coater. A primer-coated mesh substrate, in contact with the negative terminal of the mineral coater (with the coated surface exposed), was suspended one inch (25.4 mm) above the mineral bed. The mineral was electrostatically transferred to the coating surface by applying a DC current of 20 kV to 25 kV to both ends of the metal plate and the primer-coated mesh substrate. The coated mesh substrate is then partially cured in a 200℉ (93℃) oven for 30 minutes to produce an abrasive-coated mesh substrate.

[0130] Then, using the matching coating operation described above, the abrasive-coated mesh substrate was coated again with the coating composition. The coated mesh substrate was then finally cured in an oven at 230℉ (110℃) for 2 hours to prepare Example 1.

[0131] like Figures 3 to 6 As shown in the optical microscope image, a chemically cross-linked, patterned coated functional layer covers a portion of the opening in the mesh substrate, and subsequent primer, abrasive particles, and top coat are placed on top of the patterned coated functional layer.

[0132] Example 2

[0133] Example 2 was prepared according to the same process as described in Example 1, except that a template with a regularly repeating square array pattern measured to be 4 mm wide, 4 mm high, and 6 mm spaced was used. A chemically cross-linked, patterned coated functional layer covered a portion of the opening in the mesh substrate, such that the subsequent primer, abrasive particles, and top coat were placed on top of the patterned coated functional layer.

[0134] All references, patents, and patent applications cited in the above-mentioned patent-certified applications are incorporated herein by reference in their entirety. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail. The foregoing description, given to enable those skilled in the art to practice this disclosure protected by the claims, should not be construed as a limitation on the scope of this disclosure, which is defined by the claims and all their equivalents.

Claims

1. An abrasive product, comprising: A porous substrate having an opening extending through the porous substrate between opposing first and second main surfaces; An abrasive coating is disposed on only a portion of a first primary surface of the porous substrate, wherein the abrasive coating comprises: A non-adjacent patterned functional layer, the functional layer being disposed on only a portion of a first main surface of the porous substrate, wherein the functional layer comprises a first chemically cross-linked adhesive, wherein the functional layer completely blocks a first portion of the opening and does not completely block a second portion of the opening; A primer layer disposed on at least a portion of the functional layer opposite the porous substrate, wherein the primer layer comprises a second chemically cross-linked adhesive composition; and Abrasive particles, said abrasive particles being dispersed in or at least partially embedded in the primer layer, The second portion of the opening allows the abrasive particles to pass through the abrasive article.

2. The abrasive article according to claim 1, wherein the abrasive particles are dispersed in the base adhesive layer.

3. The abrasive article according to claim 1, wherein the porous substrate comprises a mesh woven fabric.

4. The abrasive article according to claim 1, wherein the porous substrate comprises a knitted fabric having a volumetric porosity of at least 20%.

5. The abrasive article according to claim 1, wherein the porous substrate comprises a metal wire mesh screen.

6. The abrasive article according to claim 1, wherein the porous substrate comprises a perforated polymer membrane.

7. The abrasive article according to claim 1, wherein the first chemically crosslinked binder comprises a crosslinked acrylic polymer.

8. The abrasive article according to claim 1, wherein the second chemically crosslinked binder composition comprises a phenolic resin.

9. The abrasive article of claim 1, wherein the abrasive particles are partially embedded in the base layer, and further comprising a top layer disposed on at least a portion of the base layer, wherein the top layer comprises a third crosslinked adhesive composition.

10. The abrasive article according to claim 9, wherein the third crosslinked binder composition comprises a phenolic resin.

11. The abrasive article according to claim 1, further comprising a component of a two-piece hook-and-loop attachment system fixed to the porous substrate opposite to the functional layer.

12. A method for manufacturing abrasive articles, the method comprising: A porous substrate is provided having an opening extending through the porous substrate between opposing first and second main surfaces; A crosslinkable functional layer precursor is disposed on the first main surface of the porous substrate, wherein the crosslinkable functional layer precursor completely blocks a first portion of the opening and does not completely block a second portion of the opening; The crosslinkable functional layer precursor is crosslinked to provide a crosslinked functional layer, wherein the crosslinked functional layer is non-adjacent and patterned. A curable primer precursor is disposed on at least a portion of the crosslinked functional layer opposite to the porous substrate, wherein the curable primer precursor has abrasive particles dispersed therein. And at least partially cure the curable primer precursor, The second portion of the opening allows the abrasive particles to pass through the abrasive article.

13. A method for manufacturing abrasive articles, the method comprising: A porous substrate is provided having an opening extending through the porous substrate between opposing first and second main surfaces; A crosslinkable functional layer precursor is disposed on the first main surface of the porous substrate, wherein the crosslinkable functional layer precursor completely blocks a first portion of the opening and does not completely block a second portion of the opening; The crosslinkable functional layer precursor is crosslinked to provide a crosslinked functional layer, wherein the crosslinked functional layer is non-adjacent and patterned. A curable primer precursor is disposed on at least a portion of the crosslinked functional layer opposite to the porous substrate; The abrasive particles are partially embedded in the curable primer precursor; The curable primer precursor is at least partially cured to provide the primer layer; A curable adhesive layer precursor is disposed on at least a portion of the base adhesive layer and the abrasive particles; as well as The curable adhesive precursor is at least partially cured to provide the abrasive article. The second portion of the opening allows the abrasive particles to pass through the abrasive article.

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