CN111448033B

CN111448033B - Bonded abrasive article and method of making same

Info

Publication number: CN111448033B
Application number: CN201880079314.1A
Authority: CN
Inventors: 梅利莎·C·席洛-阿姆斯特朗
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2017-12-08
Filing date: 2018-12-06
Publication date: 2022-05-03
Anticipated expiration: 2038-12-06
Also published as: EP3720656A1; WO2019111210A1; CN111448033A; US20200290174A1

Abstract

The present invention provides a bonded abrasive article comprising a bonded abrasive matrix. The bonded abrasive matrix comprises: 10 to 30 wt% of a phenolic resin binder, based on the total weight of the bonded abrasive matrix; abrasive particles retained in the phenolic resin binder; and 0.001 to 9 wt% of ethyl maltol. Methods of manufacture and use are also disclosed.

Description

Bonded abrasive article and method of making same

Technical Field

The present disclosure broadly relates to bonded abrasive articles and methods of making and using the same.

Background

Bonded abrasives include abrasive particles retained in a binder. Bonded abrasive types include, for example, grinding wheels, cutting wheels, fine grindstones, and grindstones. Two types of binders are commonly used. These binders include glassy inorganic binders (vitreous binding) and resinous organic binders (resin binding). Many bonded abrasive articles include a phenolic binder comprising the reaction product of one or more curable phenolic resins.

Such phenolic resin bonded abrasive products typically have an unpleasant odor during grinding/cutting because the formaldehyde by-product of the phenol and resin is released and because other components of the wheel, including but not limited to the fiberglass reinforcement, labels, and filler materials, reach a temperature at which burning, sublimation, or evaporation occurs. In such cases, the odor may be a complex mixture of aromatic components. The interaction between the various odors often produces the overall odor in a complex manner.

Disclosure of Invention

To counteract this unpleasant odor, fragrance additives that emit a more pleasant odor during use of the wheel may be included in the phenolic resin bonding formulation. Although many fragrances may be used, the present inventors have discovered, by chance, that ethyl maltol provides a pleasant aroma in phenolic resin bonded abrasive wheels, thereby producing an aroma that resembles the taste of baked bread during use, which overcomes the problem of unpleasant odors during grinding.

Accordingly, in a first aspect, the present disclosure provides a bonded abrasive article comprising a bonded abrasive matrix, wherein the bonded abrasive matrix comprises, based on the total weight of the bonded abrasive matrix:

10 to 30 wt% of a phenolic resin binder;

abrasive particles retained in the phenolic resin binder; and

0.001 to 9% by weight of ethyl maltol.

In a second aspect, the present disclosure provides a method of making a bonded abrasive article, the method comprising:

mixing components comprising:

a curable phenolic binder precursor;

abrasive particles; and

ethyl maltol; and

curing the curable phenolic binder precursor to provide a bonded abrasive matrix,

wherein the bonded abrasive matrix comprises: 10 to 30 weight percent phenolic resin binder, abrasive particles retained in the phenolic resin binder, and 0.001 to 9 weight percent of the ethyl maltol, based on the total weight of the bonded abrasive matrix.

As used herein:

the term "bonded abrasive matrix" refers to a unitary mass of abrasive particles, binder resin, and optional additives such as, for example, fillers, pore formers, fragrances, reinforcing fibers and scrims, and antiloading compounds. It does not include the external components of the bonded abrasive article, such as, for example, the hub, shaft, and label.

The features and advantages of the present disclosure will be further understood upon consideration of the detailed description and appended claims.

Drawings

Fig. 1 is a schematic perspective view of an exemplary bonded abrasive cutoff wheel according to one embodiment of the present disclosure; and is

FIG. 2 is a schematic cross-sectional side view of the exemplary bonded abrasive cutoff wheel shown in FIG. 1 taken along line 2-2.

Repeat use of reference characters in the present specification and drawings is intended to represent 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 that will fall within the scope and spirit of the principles of this disclosure.

The figures may not be drawn to scale.

Detailed Description

Bonded abrasive articles according to the present disclosure include abrasive particles retained in a bonded abrasive matrix (also referred to as a bond). The bonded abrasive matrix comprises a phenolic binder formed by curing a curable resole, novolac epoxy, or preferably a combination of resole and novolac epoxy.

Novolac epoxy resins are characterized by being acid catalyzed and a formaldehyde to phenol ratio of less than one, typically between 0.5:1 and 0.8: 1. The resole phenolic resin is characterized by being base catalyzed and having a formaldehyde to phenol ratio of greater than or equal to one, typically from 1:1 to 3: 1. Novolac epoxy resins and resole phenolic resins may be chemically modified (e.g., by reaction with an epoxy compound), or they may be unmodified.

Curable phenolic resins are well known and readily available from commercial sources. Examples of commercially available novolac epoxy RESINs include DUREZ 1364, a two-step powdered phenolic RESIN sold under the trade name VARCUM (e.g., 29302) by dorez Corporation of idesan, Texas, or HEXION AD5534 rein (HEXION Specialty Chemicals, inc., Louisville, Kentucky). Examples of commercially available resoles that may be used in the practice of the present disclosure include those sold under the tradename VARCUM (e.g., 29217, 29306, 29318, 29338, 29353) by Durez Corporation (Durez Corporation); those sold under the trade name aerofen (e.g., aerofen 295) by Ashland Chemical company of barton, Florida, usa; and those sold under the trade name PHENOLITE (e.g., PHENOLITE TD-2207) by South of the river Chemical ltd, Seoul, South Korea, Seoul.

The curable phenolic resin may comprise at least one catalyst to facilitate curing. Exemplary acidic catalysts suitable for curing phenolic resins include sulfuric acid, hydrochloric acid, phosphoric acid, oxalic acid, and p-toluenesulfonic acid. Suitable basic catalysts for curing phenolic resins include sodium hydroxide, barium hydroxide, potassium hydroxide, calcium hydroxide, organic amines or sodium carbonate. A catalyst and/or initiator may be added to the bonded abrasive matrix precursor (i.e., the material that forms the bonded abrasive matrix upon curing) depending on the desired organic binder material. Typically, heat is applied to promote curing of the bonded abrasive matrix precursor material; however, other energy sources (e.g., microwave radiation, ultraviolet light, visible light) may also be used. The particular curing agent and amount used will be apparent to those skilled in the art.

The bonded abrasive matrix comprises 10 to 30 wt.%, preferably 15 to 25 wt.%, of a phenolic resin binder, based on the total weight of the bonded abrasive matrix. In some preferred embodiments, the curable phenolic resin comprises a mixture of 4 to 8 parts by weight of a resole resin per 8 to 16 parts by weight of novolac epoxy resin, preferably 5 to 7 parts by weight of a resole resin per 9 to 15 parts by weight of novolac epoxy resin, and more preferably about 6 parts by weight of a resole resin per 10 to 14 parts by weight of novolac epoxy resin.

Phenolic resins can be used both in powder form and in liquid form. Although phenolic resins are widely used, it is within the scope of the present disclosure to include other organic binder materials including, for example, epoxy resins, urea-formaldehyde resins, aminoplasts, and epoxy-reactive acrylic binders. The organic binder material may also be modified with other binder materials to improve or alter the properties of the binder material.

In some embodiments, the bonded abrasive article (e.g., a wheel) includes about 10 wt% to about 70 wt% abrasive particles (e.g., shaped and/or crushed abrasive particles), typically 30 wt% to 65 wt%, and more typically 45 wt% to 65 wt%, based on the total weight of the binder material and abrasive particles.

The bonded abrasive article may comprise crushed abrasive particles, either by themselves or in combination with shaped abrasive particles. If both shaped abrasive particles and crushed abrasive particles are used, the crushed abrasive particles typically have one or more size grades finer than the shaped abrasive particles (e.g., if multiple size grades are used), although this is not required.

Useful crushed abrasive particles include, for example, the following crushed particles: fused aluminum oxide, heat treated aluminum oxide, white fused aluminum oxide, CERAMIC aluminum oxide materials such as those commercially available under the trade designation 3M CERAMIC ABRASIVE GRAIN from 3M Company (st. paul, Minnesota) of saint paul, Minnesota, usa, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, tungsten carbide, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina zirconia, sol-gel process-prepared abrasive particles, iron oxide, chromium oxide (chromia), ceria, zirconia, titanium dioxide, silicates, tin oxide, silica (such as quartz, glass beads, glass bubbles, and glass fibers), silicates (such as talc, clay (e.g., montmorillonite), feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate), flint, and emery. Examples of sol-gel prepared abrasive particles can be found in U.S. Pat. Nos. 4,314,827(Leitheiser et al), 4,623,364(Cottringer et al), 4,744,802(Schwabel), 4,770,671(Monroe et al), and 4,881,951(Monroe et al). It is also contemplated that the abrasive particles may comprise abrasive agglomerates such as, for example, those described in U.S. Pat. No. 4,652,275(Bloecher et al) or U.S. Pat. No. 4,799,939(Bloecher et al).

Abrasive particles (e.g., shaped and/or crushed abrasive particles) comprised of crystallites of alpha alumina, magnesium aluminate spinel, and rare earth hexaaluminates can be prepared using sol-gel alpha alumina particle precursors according to methods described in, for example, U.S. patent 5,213,591(Celikkaya et al) and U.S. patent application publications 2009/0165394 a1(Culler et al) and 2009/0169672 a1(Erickson et al).

In some embodiments, the alpha alumina-based abrasive particles (e.g., shaped abrasive particles) can be made according to a multi-step process. In brief, the method comprises the steps of: producing a sol-gel alpha alumina precursor dispersion that can be converted to alpha alumina, either seeded or unseeded; filling one or more mold cavities of shaped abrasive particles having a desired profile with a sol-gel, drying the sol-gel to form abrasive particle precursors; removing the shaped abrasive particle precursor from the mold cavity; the shaped abrasive particle precursor is calcined to form a calcined shaped abrasive particle precursor, and the calcined shaped abrasive particle precursor is then sintered to form a shaped abrasive particle. The process will now be described in more detail.

The first process step involves providing a seeded or unseeded alpha alumina precursor dispersion that can be converted to alpha alumina. The alpha alumina precursor dispersion typically comprises a liquid that is a volatile component. In one embodiment, the volatile component is water. The dispersion should contain a sufficient amount of liquid to make the viscosity of the dispersion low enough to fill the mold cavity and replicate the mold surface, but not so much liquid as to result in excessive costs for subsequent removal of the liquid from the mold cavity. In one embodiment, the alpha alumina precursor dispersion comprises from 2% to 90% by weight of particles convertible to alpha alumina, such as particles of alumina monohydrate (boehmite), and at least 10%, or from 50% to 70%, or from 50% to 60% by weight of a volatile component, such as water. Conversely, the alpha alumina precursor dispersion in some embodiments contains from 30 wt% to 50 wt%, or from 40 wt% to 50 wt% solids.

Alumina hydrates other than boehmite can also be used. Boehmite can be prepared by known techniques or is commercially available. Examples of commercially available boehmite include products having the trade names "DISPERAL" and "DISPAL", both available from Sasol North America corporation of Houston, Texas (Sasol North America, inc., Houston, Texas); or a product having the trade designation "HiQ-40" available from Basff Corporation of Fremom Park, N.J. (BASF Corporation, Florham Park, N.J.). These alumina monohydrate are relatively pure; that is, they contain relatively few, if any, other hydrate phases in addition to a monohydrate, and have a high surface area.

The physical properties of the resulting shaped abrasive particles will generally depend on the type of material used in the alpha alumina precursor dispersion. In one embodiment, the alpha alumina precursor dispersion is in a gel state. As used herein, a "gel" is a three-dimensional network of solids dispersed in a liquid.

The alpha alumina precursor dispersion may contain a modifying additive or a precursor of a modifying additive. Modifying additives may be used to enhance certain desired characteristics of the abrasive particles or to increase the efficiency of subsequent sintering steps. The modifying additive or precursor of the modifying additive may be in the form of a soluble salt, typically a water soluble salt. They generally consist of metal-containing compounds and can be precursors of the oxides of: magnesium, zinc, iron, silicon, cobalt, nickel, zirconium, hafnium, chromium, yttrium, praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, titanium, and mixtures thereof. The specific concentrations of these additives that may be present in the alpha alumina precursor dispersion may vary based on the skilled artisan.

Typically, the introduction of a modifying additive or precursor of a modifying additive will cause the alpha alumina precursor dispersion to gel. The alpha alumina precursor dispersion may also be caused to gel by the application of heat for more than a certain period of time. The alpha alumina precursor dispersion may also contain a nucleating agent (seed) to promote the conversion of hydrated alumina or calcined alumina to alpha alumina. Nucleating agents suitable for use in the present disclosure include alpha-alumina, alpha-iron oxide or precursors thereof, titanium dioxide and titanates, fine particles of chromium oxide, or any other material that nucleates a conversion product. If a nucleating agent is used, it should be present in sufficient quantity to convert the alpha alumina. Methods of nucleating such alpha alumina precursor dispersions are disclosed in U.S. patent 4,744,802 (Schwabel).

A peptizing agent can be added to the alpha alumina precursor dispersion to produce a more stable hydrosol or colloidal alpha alumina precursor dispersion. Suitable peptizing agents are monoprotic acids or acidic compounds, such as acetic acid, hydrochloric acid, formic acid and nitric acid. Polyprotic acids can also be used, but they can rapidly gel the alpha alumina precursor dispersion, making it difficult to handle or introduce additional components thereto. Certain commercial sources of boehmite have an acid titer (such as absorbed formic or nitric acid) that helps to form stable alpha alumina precursor dispersions.

The alpha alumina precursor dispersion can be formed by any suitable method, such as, for example, by simply mixing the alumina monohydrate with water containing a peptizing agent, or by forming a slurry of the alumina monohydrate to which the peptizing agent has been added.

An anti-foaming agent or other suitable chemical may be added to reduce the tendency of air bubbles or entrained air to form during mixing. Other chemicals such as wetting agents, alcohols, or coupling agents may be added if desired. Alpha alumina abrasive particles may contain silica and iron oxide as disclosed in U.S. patent 5,645,619(Erickson et al). The alpha alumina abrasive particles may contain zirconia as disclosed in U.S. Pat. No. 5,551,963 (Larmie). Alternatively, the alpha alumina abrasive particles may have a microstructure or additives as disclosed in U.S. Pat. No. 6,277,161 (Castro).

The second process step involves providing a mold having at least one mold cavity, preferably a plurality of cavities. The mold may have a substantially planar bottom surface and a plurality of mold cavities. The plurality of cavities may be formed in a production tool. The production tool may be a ribbon, a sheet, a continuous web, a coating roll (such as a rotogravure roll), a sleeve mounted on a coating roll, or a mold. In one embodiment, the production tool comprises a polymeric material. Examples of suitable polymeric materials include thermoplastics such as polyesters, polycarbonates, poly (ether sulfone), poly (methyl methacrylate), polyurethanes, polyvinyl chloride, polyolefins, polystyrene, polypropylene, polyethylene, or combinations thereof, or thermosets. In one embodiment, the entire mold is made of a polymeric or thermoplastic material. In another embodiment, the surface of the mold that comes into contact with the sol-gel when dried (such as the surface of the plurality of cavities) comprises a polymeric or thermoplastic material, and other portions of the mold may be made of other materials. By way of example, a suitable polymer coating may be applied to the metal mold to alter its surface tension characteristics.

Polymeric or thermoplastic tools can be replicated from a metal master tool. The master tool will have the inverse pattern desired for the production tool. The master tool can be made in the same manner as the production tool. In one embodiment, the master tool is made of a metal, such as nickel, and is diamond turned. The polymeric sheet material can be heated along with the master tool such that the master tool pattern is imprinted on the polymeric material by pressing the two together. A polymer or thermoplastic material can also be extruded or cast onto the master tool and then pressed. The thermoplastic material is cooled to harden it, thereby producing the production tool. If a thermoplastic production tool is utilized, care should be taken not to generate excessive heat, which can deform the thermoplastic production tool, thereby limiting its life. More information on the design and manufacture of production or master tools can be found in U.S. Pat. No. 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).

The cavity is accessible from an opening in either the top or bottom surface of the mold. In some cases, the cavity may extend through the entire thickness of the mold. Alternatively, the cavity may extend only a portion of the thickness of the mold. In one embodiment, the top surface is substantially parallel to the bottom surface of the mold, wherein the mold cavities have a substantially uniform depth. At least one side of the mold, i.e., the side in which the cavity is formed, may remain exposed to the ambient atmosphere during the step of removing the volatile component.

The cavities have a particular three-dimensional shape to produce shaped abrasive particles. The depth dimension is equal to the vertical distance from the top surface to the lowest point on the bottom surface. The depth of a given cavity may be uniform or may vary along its length and/or width. The cavities of a given mold may have the same shape or different shapes.

The third process step involves filling the cavities in the mold with an alpha alumina precursor dispersion (e.g., by conventional techniques). In some embodiments, a knife roll coater or a vacuum slot die coater may be used. If desired, a release agent may be used to aid in the removal of the particles from the mold. Typical release agents include oils (such as peanut or mineral oil, fish oil), silicones, polytetrafluoroethylene, zinc stearate and graphite. Generally, a release agent such as peanut oil in a liquid such as water or alcohol is applied to the surface of the production mold in contact with the sol-gel such that when release is desired, between about 0.1mg/in is present per unit area of mold²(0.02mg/cm²) To about 3.0mg/in²(0.46mg/cm²) Or between about 0.1mg/in²(0.02mg/cm²) To about 5.0mg/in²(0.78mg/cm²) A release agent therebetween. In some embodiments, the top surface of the mold is coated with an alpha alumina precursor dispersion. The alpha alumina precursor dispersion may be pumped onto the top surface.

Next, the alpha alumina precursor dispersion can be pressed completely into the cavity of the mold using a doctor blade or a leveling bar. The remainder of the alpha alumina precursor dispersion that does not enter the cavity can be removed from the top surface of the mold and recycled. In some embodiments, a small portion of the alpha-alumina precursor dispersion may remain on the top surface, and in other embodiments, the top surface is substantially free of dispersion. The pressure applied by the doctor blade or smoothing bar is typically less than 100psi (0.7MPa), less than 50psi (0.3MPa), or even less than 10psi (69 kPa). In some embodiments, the unexposed surface of the alpha alumina precursor dispersion extends substantially beyond the top surface to ensure uniformity in the thickness of the resulting shaped abrasive particles.

The fourth process step involves the removal of volatile components to dry the dispersion. Advantageously, the volatile components are removed at a fast evaporation rate. In some embodiments, the removal of the volatile components by evaporation is performed at a temperature above the boiling point of the volatile components. The upper limit of the drying temperature generally depends on the material from which the mold is made. For polypropylene molds, the temperature should be below the melting point of the plastic. In one embodiment, the drying temperature may be between about 90 ℃ to about 165 ℃, or between about 105 ℃ to about 150 ℃, or between about 105 ℃ to about 120 ℃ for aqueous dispersions containing between about 40% to 50% solids and polypropylene molds. Higher temperatures can lead to improved production speeds, but can also lead to degradation of the polypropylene mold, thereby limiting its useful life as a mold.

The fifth process step involves removing the resulting precursor shaped abrasive particles from the mold cavities. The shaped abrasive particle precursor may be removed from the cavity by: the following processes are used on the mold, either alone or in combination: gravity operated, vibratory, ultrasonic vibratory, vacuum operated or pressurized air processes remove particles from the mold cavity.

The abrasive particle precursor may be further dried outside the mold. This additional drying step is not necessary if the alpha alumina precursor dispersion is dried to the desired level in the mold. However, it is in some cases economical to employ this additional drying step to minimize the residence time of the alpha alumina precursor dispersion in the mold. Typically, the shaped abrasive particle precursor will be dried at a temperature of 50 ℃ to 160 ℃ or 120 ℃ to 150 ℃ for 10 minutes to 480 minutes or 120 minutes to 400 minutes.

The sixth process step involves calcining the precursor shaped abrasive particles. During calcination, substantially all of the volatile materials are removed and the various components present in the alpha alumina precursor dispersion are converted to metal oxides. Typically, the shaped abrasive particle precursor is heated to a temperature of 400 ℃ to 800 ℃ and maintained within this temperature range until the free water and 90 wt.% or more of any bound volatile materials are removed. In an optional step, it may be desirable to introduce the modifying additive by an impregnation process. The water-soluble salt may be introduced by injecting it into the pores of the calcined precursor shaped abrasive particles. The shaped abrasive particle precursor is then pre-fired again. This optional step is further described in us patent 5,164,348 (Wood).

The seventh process step involves sintering the calcined precursor shaped abrasive particles to form alpha alumina particles. Prior to sintering, the calcined precursor shaped abrasive particles are not fully densified and, therefore, lack the hardness required to function as shaped abrasive particles. The sintering is carried out according to the following steps: the calcined precursor shaped abrasive particles are heated to a temperature of 1000 ℃ to 1650 ℃ and held within this temperature range until substantially all of the alpha-alumina monohydrate (or equivalent) is converted to alpha-alumina and the porosity is reduced to less than 15 volume percent. The length of time that the calcined precursor shaped abrasive particles must be exposed to the sintering temperature to achieve this level of conversion depends on a number of factors, but is typically from five seconds to 48 hours.

In another embodiment, the duration of the sintering step is in the range of one minute to 90 minutes. After sintering, the shaped abrasive particles can have a Vickers hardness of 10GPa, 16GPa, 18GPa, 20GPa, or greater.

Other steps may be used to modify the process such as, for example, rapidly heating the material from the calcination temperature to the sintering temperature, centrifuging the alpha alumina precursor dispersion to remove sludge and/or waste. Furthermore, the method can be modified, if desired, by combining two or more of the method steps. Conventional process steps that may be used to modify the process of the present disclosure are more fully described in U.S. patent 4,314,827 (leithiser).

More information regarding the method of making shaped abrasive particles is in U.S. patent application publication 2009/0165394 Al (Culler et Al).

The shaped abrasive particles are preferably made using a tool (i.e., a die) that is cut using a diamond die, which provides higher feature definition than other manufacturing alternatives such as, for example, stamping or punching. Typically, the cavities in the tool surface have planes that meet along sharp edges and form the sides and top of a truncated pyramid. The resulting shaped abrasive particles have respective nominal average shapes that correspond to the shape of the cavities in the tool surface (e.g., truncated pyramids); however, variations (e.g., random variations) in the nominal average shape can occur during manufacture, and shaped abrasive particles exhibiting such variations are included within the definition of shaped abrasive particles as used herein.

Preferably, the base and top of the shaped abrasive particles are substantially parallel, resulting in a prismatic or truncated pyramidal shape, and the dihedral angle between the base and each side may independently range from 45 degrees to 90 degrees, typically from 70 degrees to 90 degrees, more typically from 75 degrees to 85 degrees, although these are not required.

As used herein, the term "length" when referring to shaped abrasive particles refers to the largest dimension of the shaped abrasive particles. "width" refers to the largest dimension of the shaped abrasive particle perpendicular to the length. "thickness" or "height" refers to the dimension of the shaped abrasive particle perpendicular to the length and width.

The shaped abrasive particles are typically selected to have a length in the range of 0.001mm to 26mm, more typically 0.1mm to 10mm, and more typically 0.5mm to 5mm, although other lengths may also be used. In some embodiments, the length may be expressed as a portion of the thickness of the bonded abrasive article (e.g., wheel) having abrasive particles contained therein. For example, the shaped abrasive particles can have a length greater than half the thickness of the bonded abrasive wheel. In some embodiments, the length of the shaped abrasive particles can be greater than the thickness of the bonded abrasive wheel.

The shaped abrasive particles are typically selected to have a width in the range of 0.001mm to 26mm, more typically 0.1mm to 10mm, and more typically 0.5mm to 5mm, although other lengths may also be used.

The shaped abrasive particles are typically selected to have a thickness in the range of 0.005mm to 1.6mm, more typically 0.2mm to 1.2 mm.

In some embodiments, the shaped abrasive particles can have an aspect ratio (length to thickness) of at least 2, 3, 4, 5,6, or more.

Surface coatings on the shaped abrasive particles can be used to improve adhesion between the shaped abrasive particles and the binder material in the abrasive article, or can be used to aid in electrostatic deposition of the shaped abrasive particles. In one embodiment, the surface coating described in U.S. Pat. No. 5,352,254(Celikkaya) can be used in an amount of 0.1% to 2% relative to the weight of the shaped abrasive particles. Such surface coatings are described in U.S. patent 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). In addition, the surface coating may prevent plugging of the shaped abrasive particles. The term "capping" is used to describe the phenomenon in which metal particles from the workpiece being abraded weld to the tops of the shaped abrasive particles. Surface coatings that perform the above functions are known to those skilled in the art.

Typically, the crushed abrasive particles are individually 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 (european union of manufacturers of abrasives), and JIS (japanese industrial standard). Such industry accepted grading standards include: for example, ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI24, ANSI 30, ANSI 36, ANSI 40, ANSI 50, ANSI 60, ANSI 80, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI240, 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, 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 8, JIS 12, JIS 16, JIS 24, JIS36, 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, JIS 6000, JIS 8000 and JIS10,000. More typically, the size of the comminuted alumina particles and the alumina-based abrasive particles prepared by the seedless sol-gel process are independently set to ANSI 60 and 80 or FEPA F36, F46, F54 and F60 or FEPA P60 and P80 classification standards.

Alternatively, the abrasive particles may be classified into a nominal screen grade using a U.S. Standard test Sieve conforming to ASTM E-11, "Standard Specifications for Wire Cloth and Sieves for Testing Purposes". Astm e-11 specifies the design and construction requirements for a test screen that uses a woven screen cloth media mounted in a frame to sort materials according to a specified particle size. Typical designations are 18+20, which means that the shaped abrasive particles pass through a test sieve number 18, which conforms to ASTM E-11 specifications, but remain on a test sieve number 20, which conforms to ASTM E-11 specifications. In one embodiment, the shaped abrasive particles have a particle size of: such that a majority of the particles pass through the 18 mesh test sieve and may be retained on the 20, 25, 30, 35, 40, 45 or 50 mesh visual test sieve. In various embodiments, the shaped abrasive particles can have a nominal sieve rating comprising: -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, a custom mesh size such as-90 +100 may be used.

For example, the abrasive particles can be uniformly or non-uniformly distributed throughout the bonded abrasive article. For example, if the bonded abrasive wheel is a grinding or cutting wheel, the abrasive particles may be concentrated toward an intermediate region (e.g., located away from the outer surface of the grinding or cutting wheel), or only at the outer edge, i.e., periphery, of the grinding or cutting wheel. The central portion may contain a relatively small amount of abrasive particles. In another variation, the first abrasive particle may be on one side of the wheel and the different abrasive particle may be on the other side. However, typically all of the abrasive particles are uniformly distributed among each other because the wheel is easier to manufacture.

Bonded abrasive articles according to the present disclosure may include additional abrasive particles beyond those described above, but are limited by the weight range requirements that other components are intended to meet. Examples include fused aluminum oxide (including fused alumina-zirconia), brown aluminum oxide, blue aluminum oxide, silicon carbide (including green silicon carbide), garnet, diamond, cubic boron nitride, boron carbide, chromia, ceria, and combinations thereof.

Ethyl maltol (i.e., 2-ethyl-3-hydroxy-4H-pyran-4-one; CAS number 4940-11-8) is available from a number of fragrance and fine Chemical sources (e.g., Sigma-Aldrich Chemical Co., St. Louis, Missouri), St. Louis, Mo.). Ethyl maltol is present in an amount of 0.001 to 9 wt%, preferably 0.001 to 5 wt%, and preferably 0.01 to 2 wt%, based on the total weight of the bonded abrasive matrix (i.e., the solidification matrix). Ethyl maltol may be included, for example, as a solid or as a dispersion or solution in a solvent. If included in solid form, it is preferably ground to a small size, such as, for example, 1 micron to 3 millimeters, preferably 0.1 micron to 1 millimeter, or 0.5 millimeters to 1 millimeter, although this is not required.

Although ethyl maltol has limited solubility in water (1 g/l to 2 g/l at room temperature), the solubility is higher in hot water and alkaline aqueous solutions. Thus, depending on the conditions, ethyl maltol will typically be partially or completely dissolved in the bonded abrasive matrix precursor prior to curing. Without being bound by theory, the inventors believe that at least a portion of the ethyl maltol dissolves throughout the bonded abrasive matrix when cured. This will potentially reduce porosity and in some cases may result in improved grinding characteristics.

In a preferred embodiment, the bonded abrasive matrix is free of vitreous bond. This means that, at most, there is not enough glassy binder to hold the abrasive particles, and/or the glassy binder is not sufficiently uniformly distributed to hold the abrasive particles. Most preferably, no glassy binder is present at all. Exemplary glassy binders include silicon-containing glasses. Likewise, the bonded abrasive matrix precursor may be free of silicon-containing glass.

FIG. 1 illustrates an exemplary bonded abrasive article. Referring now to fig. 1, a bonded abrasive cutoff wheel 100. The bonded abrasive matrix 110 forms an endless belt around the central aperture 112 for attaching the cutting wheel 100 to, for example, a power driven tool (not shown).

Referring now to fig. 2, a cutoff wheel 100 contains shaped abrasive particles 20 and optionally conventional crushed abrasive particles 30 and a phenolic resin binder 25. Cutoff wheel 100 has an optional first scrim 115 and an optional second scrim 116 disposed on opposite

major surfaces

132, 134 of cutoff wheel 100.

In some embodiments, a bonded abrasive article according to the present disclosure comprises an additional grinding aid, such as, for example, polytetrafluoroethylene particles, cryolite, sodium chloride, FeS₂(iron disulfide), potassium aluminum fluoride, or KBF₄(ii) a The amount of grinding aid is typically from 1 to 25 weight percent, more typically from 4 to 10 weight percent, based on the total weight of the bonded abrasive matrix, but is limited by the weight range requirements to be met by the other components. Grinding aids are added to improve the cutting characteristics of the cutting wheel, typically by lowering the temperature of the cutting interface. The grinding aid can be in the form of individual particles or agglomerates of grinding aid particles. An example of precisely shaped grinding aid particles is taught in U.S. patent publication 2002/0026752A1(Culler et al).

In some embodiments, the bonded abrasive matrix contains a plasticizer, such as, for example, those commercially available under the trade designation "SANTICIZER 154 plasticizer" from united states ewingier ltd, Chicago, Illinois.

Bonded abrasive articles according to the present disclosure may include additional components such as, for example, filler particles, but are limited by the weight range requirements that the other components are intended to meet. Filler particles may be added to occupy space and/or provide porosity. The porosity allows the bonded abrasive article to be used in a flaked-off manner, or to wear away abrasive particles to expose new or fresh abrasive particles. Bonded abrasive articles (e.g., wheels) according to the present disclosure have any range of porosity; for example, about 1 to 50 volume%, typically 1 to 40 volume%. Examples of fillers include bubbles and beads (e.g., glass, ceramic (alumina), clay, polymer, metal), cork, gypsum, marble, limestone, flint, silica, aluminum silicate, and combinations thereof.

At least some of the abrasive particles may be surface treated with a coupling agent to enhance adhesion of the abrasive particles to the phenolic binder. The abrasive particles may be treated prior to combining them with the curable phenolic resin or may be surface treated in situ by including a coupling agent in the bonded abrasive matrix precursor. In one suitable method, the abrasive particles are coated with a coupling agent (e.g., an epoxy-functional silane coupling agent) and then mixed with a curable phenolic resin. The amount of coupling agent is generally selected to be an effective amount. For example, the epoxy functional silane is present in an amount of 0.01 to 3 parts, preferably 0.1 to 0.3 parts per 100 parts of abrasive particles, although amounts outside of this range may also be used. Useful epoxy-functional silane coupling agents are disclosed in PCT application publication WO 2017/062482(Schillo-Armstrong et al).

Bonded abrasive wheels according to the present disclosure may be used, for example, in cut-off wheels and center-recessed grinding wheels of type 27 (e.g., section 1.4.14 of american national standards institute standard ANSI B7.1-2000 (2000)) in the abrasives industry.

The cutting wheel is typically 0.80 millimeters (mm) to 16mm thick, more typically 1mm to 8mm, and typically has a diameter of between 2.5cm and 100cm, more typically between about 7cm and 13cm, although other sizes may be used (e.g., wheels up to 100cm in diameter are known). An optional central aperture may be used to attach the cutting wheel to the power driven tool. The central bore, if present, is typically 0.5cm to 2.5cm in diameter, although other dimensions may be used. Optional central holes may be reinforced; for example by means of metal flanges. Alternatively, a mechanical fastener may be axially fixed to one surface of the cutting wheel. Examples include screws, nuts, Tinnerman nuts, and bayonet retaining rods.

Optionally, bonded abrasive wheels, particularly cutoff wheels, according to the present disclosure may further include a scrim and/or backing for reinforcing the bonded abrasive wheel; for example, on one or both major surfaces of the bonded abrasive wheel, or in the bonded abrasive wheel. Examples include paper, polymeric films, metal foils, vulcanized fibers, synthetic and/or natural fiber nonwovens (e.g., advanced apertured nonwoven synthetic webs and meltspun scrims), synthetic and/or natural fiber knits, synthetic and/or natural fiber wovens (e.g., woven glass/scrims, woven polyester fabrics, treated versions thereof, and combinations thereof). Examples of suitable porous reinforcing scrims include porous fiberglass scrims and porous polymeric scrims (e.g., comprising polyolefins, polyamides, polyesters, cellulose acetate, polyimides, and/or polyurethanes) that may be, for example, melt spun, melt blown, wet laid, or air laid. In some instances, it is desirable to include reinforcing staple fibers within the bonding medium so that the fibers are uniformly dispersed throughout the cutting wheel.

The selection of the porosity and basis weight of the various reinforcing members (e.g., scrim and backing) described herein is within the ability of those skilled in the abrasive art and generally depends on the intended use.

Bonded abrasive articles (e.g., grinding wheels and cutting wheels) according to the present disclosure are typically made by a molding process. During molding, binder material precursors, i.e., liquid organics, powdered inorganics, powdered organics, or combinations thereof, are mixed with the abrasive particles. In some cases, a liquid medium (resin or solvent) is first applied to the abrasive particles to wet their outer surfaces, and the wetted particles are then mixed with a powdered medium. Bonded abrasive articles (e.g., bonded abrasive wheels) according to the present disclosure can be made by compression molding, injection molding, transfer molding, and the like. The moulding may be done by hot or cold pressing or any suitable means known to the person skilled in the art.

The curing temperature of the organic binder precursor material will vary depending on the material selected and the type and design (e.g., wheel design) of the bonded abrasive article. The selection of suitable conditions is within the ability of one of ordinary skill in the art. Exemplary conditions for the phenolic binder may include: about 20 tons (244 kg/cm) per 4 inch diameter were applied at room temperature²) And then heating the temperature to up to about 185 c for a time sufficient to cure the organic binder precursor material.

Bonded abrasive wheels according to the present disclosure may be used, for example, to abrade a workpiece. For example, they may be formed into grinding or cutting wheels that exhibit good grinding characteristics while maintaining relatively low operating temperatures that avoid thermal damage to the workpiece.

The cutting wheel may be used on any right angle grinding tool, such as those available, for example, from england (Ingersoll-Rand), soxhlet (Sioux), Milwaukee (Milwaukee), and the ashex brand of ashex, North Carolina (Apex Brands, Apex, North Carolina). The tool may be electric or pneumatic, typically at a speed of about 1000RPM to 50000 RPM.

In use, the bonded abrasive wheel can be used for dry or wet grinding. In wet milling, the wheel is used in combination with water, an oil-based lubricant, or a water-based lubricant. Bonded abrasive wheels according to the present disclosure are particularly useful on a variety of workpiece materials, such as, for example, carbon steel sheet or bar stock and more exotic metals (e.g., stainless steel or titanium) or softer ferrous metals (e.g., mild steel, low alloy steel, or cast iron).

Selected embodiments of the present disclosure

In a first embodiment, the present disclosure provides a bonded abrasive article comprising a bonded abrasive matrix, wherein the bonded abrasive matrix comprises, based on the total weight of the bonded abrasive matrix:

10 to 30 wt% of a phenolic resin binder;

abrasive particles retained in the phenolic resin binder; and

0.001 to 9% by weight of ethyl maltol.

In a second embodiment, the present disclosure provides the bonded abrasive article of the first embodiment, wherein the bonded abrasive matrix is free of vitreous bond precursors.

In a third embodiment, the present disclosure provides the bonded abrasive article of the second embodiment, wherein the vitreous bond precursor comprises a silicon-containing glass or a precursor thereof.

In a fourth embodiment, the present disclosure provides the bonded abrasive article of any one of the first to third embodiments, wherein the phenolic binder comprises a resole and a novolac epoxy component.

In a fifth embodiment, the present disclosure provides the bonded abrasive article of any one of the first to fourth embodiments, wherein the ethyl maltol is at least partially dissolved in the phenolic resin binder.

In a sixth embodiment, the present disclosure provides the bonded abrasive article of any one of the first to fifth embodiments, wherein the ethyl maltol is present in an amount of 0.1 to 2 wt.%, based on the total weight of the bonded abrasive matrix.

In a seventh embodiment, the present disclosure provides the bonded abrasive article of any one of the first to sixth embodiments, wherein the bonded abrasive matrix comprises an annulus disposed about a central aperture.

In an eighth embodiment, the present disclosure provides a method of making a bonded abrasive article, the method comprising:

mixing components comprising:

a curable phenolic binder precursor;

abrasive particles; and

ethyl maltol; and

In a ninth embodiment, the present disclosure provides a method of making a bonded abrasive article according to the eighth embodiment, wherein the bonded abrasive matrix is free of vitreous bond precursors.

In a tenth embodiment, the present disclosure provides a method of making a bonded abrasive article according to the ninth embodiment, wherein the vitreous bond precursor comprises a silicon-containing glass or a precursor thereof.

In an eleventh embodiment, the present disclosure provides a method of making a bonded abrasive article according to any one of the eighth to tenth embodiments, wherein the phenolic resin binder comprises a resole phenolic resin binder.

In a twelfth embodiment, the present disclosure provides the method of making a bonded abrasive article of any one of the eighth to eleventh embodiments, wherein the ethyl maltol is at least partially dissolved in the curable phenolic resin binder precursor.

In a thirteenth embodiment, the present disclosure provides a method of making a bonded abrasive article according to any one of the eighth to twelfth embodiments, wherein the ethyl maltol is present in an amount of 0.1 to 2 wt.%, based on the total weight of the bonded abrasive matrix.

In a fourteenth embodiment, the present disclosure provides a method of making a bonded abrasive article according to any one of the eighth to thirteenth embodiments, wherein the bonded abrasive matrix comprises an annulus belt disposed about a central aperture.

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 disclosure.

Examples

All parts, percentages, ratios, and the like in the examples and the remainder of the specification are by weight unless otherwise indicated. In these examples, grams are abbreviated as "g" and wt% means weight percent based on total weight unless otherwise specified.

Table 1 below lists the various materials used in the examples.

TABLE 1：

Preparation of abrasive particles SAP1 and SAP2

The precisely shaped alpha alumina abrasive particles SAP1 and SAP2 of the examples were prepared by molding an alumina sol-gel in an equilateral triangular polypropylene mold cavity according to the disclosure of example 1 of U.S. Pat. No. 8,142,531(Adefris et al). In addition, SAP1 and SAP2 had a coating of fine (about 0.5 micron) alumina particles (HYDRAL COAT 5, available from Almatis, Pittsburgh, Pennsylvania) applied according to the method of U.S. Pat. No. 5,213,591(Celikkaya et al).

Preparation of abrasive particle SAP3

The precisely shaped alpha alumina abrasive particles SAP3 in the examples were prepared by molding a slurry of a dispersion of non-colloidal solid alumina particles in an equilateral triangular polypropylene mold cavity according to the disclosure of example 1 of U.S. patent application publication 2015/0267097(Rosenflanz et al).

Example 1

100g of SAP1, 50g of SAP2, and 450g of AM1 abrasive particles were combined and mixed by hand. RP (60g) was added to the combined abrasive particles and the combination was mixed in a chenbo (kitchen aid) commercial mixer (model KSM C50S) at speed 1 for 7 minutes.

PP (340g) was combined with 6g of EM and mixed manually. The abrasive particle mixture was then combined with 340g of a combined PP-EM mixture and mixed for an additional 7 minutes. In the middle of the second mixing step, 5mL of PO was added to the mixture.

Example 2

Example 1 was repeated except that a PP-EM mixture was made by combining 340g PP and 12g EM. The abrasive particle mixture was still combined with a total of 340g of the combined PP-EM mixture.

Example 3

Example 1 was repeated except that a PP-EM mixture was made by combining 340g PP and 30g EM. The abrasive particle mixture was still combined with a total of 340g of the combined PP-EM mixture.

Example 4

Example 1 was repeated except that a PP-EM mixture was made by combining 340g PP and 60g EM. The abrasive particle mixture was still combined with a total of 340g of the combined PP-EM mixture.

Comparative example A

Example 1 was repeated except that no EM was used, thus combining the abrasive particle mixture with 340g PP.

Example 5

185.5g of SAP3, 87g of AM2, and 346g of AM3 of abrasive particles were combined and mixed by hand. EM (3g) was added to 60g RP and heated to 50 ℃ to dissolve the EM in the RP. The RP was then cooled to 20 ℃. The EM and RP mixture was added to the combined abrasive particles and the combination was mixed in a chembap (KitchenAid) commercial mixer (model KSM C50S) at speed 1 for 7 minutes. The abrasive particle mixture was then combined with 320g of PP and mixed for an additional 7 minutes. In the middle of the second mixing step, 6mL of PO was added to the mixture.

Example 6

Example 6 was repeated, except that 6g of EM was combined with 60g of RP.

Example 7

Example 6 was repeated, except that 12g of EM was combined with 60g of RP.

Example 8

Example 6 was repeated, except that 18g of EM was combined with 60g of RP.

Example 9

Example 6 was repeated, except that 6g of EM was combined with 60g of RP.

Comparative example B

Example 6 was repeated, except that 12g of EM was added to 320g of PP. The combined 332g was mixed with the abrasive particles and RP mixture for 7 minutes. In the middle of the second mixing step, 6mL of PO was added to the mixture.

Preparation of abrasive particles

The mixtures of examples 1 to 9, comparative example a and comparative example B were left for 20 hours at ambient conditions. Subsequently, each mixture was screened through a 14 mesh screen (+ 14/tray) to remove aggregates. A 125mm diameter disc of SCRIM2 was placed at the bottom of a 125mm diameter mold cavity. The die had an internal diameter of 23 mm. The fill mixture from example 1 (27.0g to 27.5g) was spread on top of SCRIM 2. SCRIM1 was then placed on top of the fill mixture and a small diameter experimental label was placed on top of the SCRIM. From Polish Wavowal (

Poland) a metal flange of 28mm by 22.45mm by 1.2mm of Lumet PPUH was placed on top of each label. The mold was closed and pressed at 30 tons (244.5 kg/cm) at room temperature²) The scrim-fill-scrim interlayer was pressed for 3 seconds. Three wheels were made for each mixture. After pressing, the cutting wheel precursor was removed from the mold and placed on the stack between the aluminum plate and the PTFE sheet for curingThe shape is maintained. The wheels were then cured in a stack with a 30 hour cure cycle: raising the temperature to 75 ℃ for 2 hours, raising the temperature to 90 ℃ for 2 hours, raising the temperature to 110 ℃ for 5 hours, raising the temperature to 135 ℃ for 3 hours, raising the temperature to 188 ℃ for 3 hours, keeping the temperature at 188 ℃ for 13 hours, and then cooling the mixture to 60 ℃ for 2 hours. The final thickness of the wheel was about 0.053 inches (1.35 mm).

Cutting test method

A40 inch (101.6cm) long, 1/8 inch (3.2mm) thick stainless steel sheet was held with its major surface inclined at an angle of 35 degrees to the horizontal. The guide rail is fixed along the downwardly inclined top surface of the inclined thin plate. A 4.5 inch (11.4 cm)/5 inch (12.7 cm) cutting wheel angle grinder model DeWalt D28114 was secured to the rail so that the tool was guided along a downward path under the force of gravity.

The cutting wheel for evaluation was mounted on the tool such that when the cutting wheel tool was released to shift down the rail under gravity, the cutting wheel encountered the entire thickness of the stainless steel sheet. The cutting wheel tool was activated to rotate the cutting wheel at 10000rpm, the tool was released to start lowering and the resulting cut length in the stainless steel sheet was measured after 60 seconds (one minute cut). The cutting wheel was sized before and after the cut test to determine wear. Three cutting wheels from example 1 to example 9 and comparative example a and comparative example B were tested.

One minute cut is measured as the distance ground on the stainless steel sheet in one minute of the cutting wheel. Wear rate is the loss of wheel volume as a function of wheel cutting time. The engineering property is the cut length multiplied by the wheel thickness and then divided by the mass change of the wheel. The results of the cutting tests of examples 1 to 9 and comparative examples a and B are reported in table 3 below.

The composition of the mixture for each example is reported in table 2 below.

TABLE 2

TABLE 3

Table 3 shows the performance results. Examples 1-4 and comparative example a show that the performance of the thin cutter wheel decreases as the ethyl maltitol amount increases from 1% to 5.15% and the novolac epoxy resin decreases from 13.42% to 11.52%. Examples 5 to 9 and comparative example B show that the performance of the thin cutting wheel decreases as the amount of ethyl maltol increases from 1% to 2%, but it is better to add EM to PP instead of to RP or to avoid heating the RP. The wheels made from examples 1 to 9 emitted a pleasant smell during the cutting test.

All cited references, patents, and patent applications in the above application for letters patent are incorporated by reference herein in their entirety in a consistent manner. In the event of inconsistencies or contradictions between the incorporated reference parts and the present application, the information in the preceding description shall prevail. The preceding description, given to enable one of ordinary skill in the art to practice the claimed disclosure, is not to be construed as limiting the scope of the disclosure, which is defined by the claims and all equivalents thereto.

Claims

1. A bonded abrasive article comprising a bonded abrasive matrix, wherein the bonded abrasive matrix comprises, based on the total weight of the bonded abrasive matrix:

10 to 30 wt% of a phenolic resin binder;

abrasive particles retained in the phenolic resin binder; and

0.001 to 9% by weight of ethyl maltol,

wherein the ethyl maltol is partially or completely dissolved in the precursor of the bonded abrasive matrix prior to curing and at least a portion of the ethyl maltol is dissolved throughout the bonded abrasive matrix upon curing.

2. The bonded abrasive article of claim 1, wherein the bonded abrasive matrix is free of vitreous bond precursors.

3. The bonded abrasive article of claim 2, wherein the vitreous bond precursor comprises a silicon-containing glass or a precursor thereof.

4. The bonded abrasive article of claim 1, wherein the phenolic binder comprises a resole and a novolac epoxy component.

5. The bonded abrasive article of claim 1, wherein the ethyl maltol is at least partially dissolved in the phenolic resin binder.

6. The bonded abrasive article of claim 1, wherein the ethyl maltol is present in an amount of 0.1 to 2 wt%, based on the total weight of the bonded abrasive matrix.

7. The bonded abrasive article of claim 1, wherein the bonded abrasive matrix comprises an annulus disposed around a central aperture.

8. A method of making a bonded abrasive article, the method comprising:

mixing components comprising:

a curable phenolic binder precursor;

abrasive particles; and

ethyl maltol; and

wherein the bonded abrasive matrix comprises: 10 to 30 weight percent of a phenolic resin binder, abrasive particles retained in the phenolic resin binder, and 0.001 to 9 weight percent of the ethyl maltol, based on the total weight of the bonded abrasive matrix, wherein the ethyl maltol is partially or completely dissolved in the precursor of the bonded abrasive matrix prior to curing and at least a portion of the ethyl maltol is dissolved throughout the bonded abrasive matrix upon curing.

9. The method of claim 8, wherein the bonded abrasive matrix is free of vitreous bond precursors.

10. The method of claim 9, wherein the vitreous bond precursor comprises a silicon-containing glass or a precursor thereof.

11. The method of claim 8, wherein the phenolic binder comprises a resole binder.

12. The method of claim 8, wherein the ethyl maltol is at least partially dissolved in the curable phenolic binder precursor.

13. The method of claim 8, wherein the ethyl maltol is present in an amount of 0.1 to 2 wt%, based on the total weight of the bonded abrasive matrix.

14. The method of claim 8, wherein the bonded abrasive matrix comprises an annulus disposed about a central aperture.