ES2578064T3 - Microfiber reinforcement for abrasive tools - Google Patents

Abstract

An abrasive article, comprising: an organic binder material; an abrasive material, dispersed in the binder organic material; chopped strand fibers dispersed in the binder organic material, the chopped strand fibers comprising about 0.1% by volume to about 10% by volume in the abrasive article; mineral wool microfibers that are uniformly dispersed in the binder organic material, wherein said microfibers are individual filaments; and one or more charges, including the one or more charges a manganese compound.

Description

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DESCRIPTION

Microfiber reinforcement for abrasive tools Technical field

Chopped strand fibers are used to reinforce grinding wheels based on resins. The chopped strand fibers, typically 3-4 mm in length, are a plurality of filaments. The number of filaments may vary depending on the manufacturing process, but typically consists of 400 to 6,000 filaments per bundle. The filaments are held together by an adhesive known as sizing, binder or coating, which must be basically compatible with the resin matrix. An example of a fiber of chopped strands is called 183 Cratec®, available from Owens Corning.

The incorporation of chopped strand fibers into a dry grinding wheel mixture is generally carried out by mixing the chopped strand fibers, resin, fillers and abrasive grain for a specified time and then molding, curing or otherwise processing the mixture. until a grinding wheel is finished.

In any such case, the wheels reinforced with chopped strand fibers typically suffer from several problems, including lower strength, poor grinding performance, as well as inadequate grinding wheel life, presumably due to incomplete dispersion of the filaments within the bundle. of chopped strand fibers.

There is a need, therefore, for improved reinforcement techniques for abrasive processing tools without compromising grinding performance.

US 2008/0072500 A1 proposes an abrasive article comprising an organic binder material, an abrasive material dispersed in the binder organic material, a plurality of microfibers uniformly dispersed in the binder organic material, wherein the microfibers are individual filaments, and a or more fillers that include a manganese compound.

Compendium of the invention

The present invention provides an abrasive article according to claim 1 and a method for abrasively processing a workpiece according to claim 9. The dependent claims describe further embodiments of the invention.

An embodiment of the present invention provides a composition, comprising an organic binder material (eg, thermosetting resin, thermoplastic resin or rubber), an abrasive material dispersed in the binder organic material, and microfibers uniformly dispersed in the binder organic material . Microfibers are Individual filaments, and may include, for example, mineral wool fibers, slag wool fibers, rock wool fibers, stone wool fibers, glass fibers, and in particular ground glass fibers, fiber fibers. ceramics, ground basalt fibers, carbon fibers, aramid fibers and polyamide fibers, and combinations thereof. The microfibers may have an average length, for example, less than about 1,000 pm. In a particular case, the microfibers have an average length in the range of about 100 to 500 pm and a diameter of less than about 10 micrometers. In some embodiments, chopped strand fibers are also present, e.g., fiberglass chopped strand fibers. In many cases the composition also includes one or more charges, being at least one active charge, capable of chemically reacting with the microfibers at the temperatures that occur during grinding. These chemical reactions of active loading and microfibers provide various benefits for abrasive processing (eg, improved wheel life, higher G ratio, and / or anti-loading of the abrasive face of the tool). Examples of suitable active fillers include manganese compounds, silver compounds, boron compounds, phosphorus compounds and combinations thereof. In such a specific case, the one or more active charges include manganese dichloride. Other charges that do not chemically react with microfibers can also be incorporated.

The composition may include, for example, from 10% by volume to 50% by volume of the organic binder material, from 30% by volume to 65% by volume of the abrasive material, and from 1% by volume to 20% by volume of the microfibers In another particular case, the composition includes from 25% by volume to 40% by volume of the organic binder material, from 50% by volume to 60% by volume of the abrasive material, and from 2% by volume to 10% by volume of the microfibers In another particular case, the composition includes from 30% by volume to 40% by volume of the organic binder material, from 50% by volume to 60% by volume of the abrasive material, and from 3% by volume to 8% by volume of the microfibers In some cases, the composition also contains chopped strand fibers, eg, in an amount within the range of about 0.1 to about 10% by volume, for example, about 2 to about 8% by volume.

In another embodiment, the composition is in the form of an abrasive article used in the abrasive processing of a workpiece. In such a case, the abrasive article is a grinding wheel or other suitable form for abrasive processing. Typically, the composition is an agglutinated abrasive article, eg, a grinding wheel or other type of tool, in which abrasive grains are contained in a three-dimensional binder organic matrix.

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In one aspect, an abrasive article includes an organic binder material; an abrasive material, dispersed in the binder organic material; chopped strand fibers dispersed in the binder organic material; mineral wool microfibers that are uniformly dispersed in the binder organic material, wherein said microfibers are individual filaments; and one or more charges. In specific implementations, the one or more charges include a manganese compound. In some cases, an abrasive article contains chopped strand fibers, microfibers of mineral wool, a manganese compound and, optionally, other fillers such as, for example, lime, pyrites and others, however it does not include potassium salts (e.g. e.g., potassium sulfate and / or potassium chloride).

Another embodiment of the present invention provides a method for abrasively processing a workpiece. The method includes mounting the workpiece in a machine capable of facilitating abrasive processing, and operatively attaching an abrasive article to the machine. The abrasive article includes an organic binder material, an abrasive material dispersed in the binder organic material, and microfibers uniformly dispersed in the binder organic material, wherein the microfibers are individual filaments, e.g., having an average length, for example , less than about 1,000 pm. The abrasive article may further include chopped strand fibers, dispersed in the binder organic material. In specific implementations, the abrasive article contains one or more fillers, eg, which include a manganese compound. In some cases, the abrasive article does not include potassium salts. The method continues by contacting the abrasive article with a workpiece surface.

The abrasive article may be reinforced, eg, internally reinforced, containing, for example, one or more fiberglass reinforcements. For example, an abrasive article comprises an organic binder material; an abrasive material, dispersed in the binder organic material; mineral wool microfibers that are uniformly dispersed in the binder organic material, wherein said microfibers are individual filaments; one or more charges, including the one or more charges a manganese compound; and at least one glass sheet reinforcement.

Aspects of the invention provide compositions in the form of abrasive articles such as, for example, grinding wheels or other agglutinated abrasive tools that exhibit improved strength (reflected, eg, by the maximum speed that characterizes the tool) and resistance to impact, the tools according to the embodiments of the invention being robust and less prone to breakage. The abrasive articles according to the embodiments of the invention also show improved grinding wheel wear speed, improved G ratio and longer tool life. Examples of the agglutinated articles described herein may exhibit good resistance to thermal shock, with little or no thermal cracking being observed. Abrasive articles containing glass sheet reinforcements, and, optionally, chopped strand fibers, typically show improved impact properties.

The features and advantages described herein are not fully inclusive and, in particular, many additional features and advantages will be apparent to a person skilled in the art in view of the drawings, specification and claims. In addition, it should be noted that the language used in the specification has been selected primarily for ease of reading and instructional purposes, and not to limit the scope of the content of the invention.

Brief description of the drawings

Figure 1 is a graphical representation depicting the resistance analysis of compositions configured in accordance with various embodiments of the present invention.

Figure 2 is a graphical representation depicting the grinding performance of a tool according to embodiments described herein.

Description of the realizations

As mentioned above, fibers of strands chopped in grinding wheels based on dense resin can be used to increase hardness and impact resistance, where the incorporation of fibers of chopped strands into a dry grinding wheel mixture is carried out. generally conducted by mixing the fibers of chopped strands, resin, fillers and abrasive grain for a specified time. However, the combination or mixing time plays a significant role in achieving usable mixing quality. Improper mixing may result in non-uniform mixtures that make filling and spreading molds difficult, and leads to non-homogeneous composite materials with inferior properties and high variability. On the other hand, excessive mixing leads to the formation of "diffuse balls" (clusters of multiple fibers of chopped strands) that cannot be redispersed in the mixture. In addition, the chopped strand itself is effectively a bundle of filaments linked together. In each case, such bunches or bunches effectively decrease the homogeneity of the grinding mixture and make it more difficult to transfer and spread in a mold. In addition, the presence of such clusters or bundles within the composite material decreases the properties of the composite material, such as strength and modulus, and increases the variability of the properties. Additionally, high concentrations of glass, such as chopped strands or bundles thereof, have a detrimental effect on the life of the grinding wheel. Increasing the level of strand fibers chopped in the wheel can also decrease the grinding performance (e.g., measured

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by the G and / or WWR Relationship).

In a particular embodiment of the present invention, producing microfiber reinforced composite materials involves the complete dispersion of individual filaments within a dry mixture of suitable binder material (eg, organic resins) and fillers. The full dispersion can be defined, for example, by the maximum properties of the composite material (such as strength) after molding and curing of a suitably combined / mixed combination of microfibers, binder material and fillers. For example, a poor mixture results in low resistance, but a good mixture results in high resistance. Another way to evaluate the dispersion is to isolate and weigh the non-dispersed (eg, material that resembles the original microfiber before mixing) using screening techniques. In practice, the dispersion of the microfiber reinforcements can be evaluated by visual inspection (eg, with or without a microscope) of the mixture before molding and curing. As will be apparent in the light of this description, incomplete or inadequate microfiber dispersion otherwise generally results in lower composite material properties and grinding performance.

According to various embodiments of the present invention, the microfibers are small and short individual filaments that have high tensile modulus and can be inorganic or organic. In one example, microfibers are microfibers of mineral wool, also known as scum or rock wool microfibers. Examples of other microfibers that may be used include, but are not limited to, ground glass fibers, ground basalt fibers, ceramic fibers, carbon fibers, aramid fibers or aramid pulp, polyamide or aromatic polyamide fibers.

A particular embodiment of the present invention uses a microfiber that is an individual inorganic filament with an average length that is less than or equal to about 4,000 micrometers and a filament diameter less than or equal to 40 micrometers, and a reinforcing aspect ratio ( length to diameter or L / d) of at least 10. For example, an average length of approximately 100 micrometers and filament diameter of approximately 10 micrometers results in a reinforcing aspect ratio of 10. A filament length of approximately 50 micrometers With a filament diameter of approximately 5 micrometers it has a reinforcing aspect ratio of 10. Similarly, a filament length of approximately 20 with a filament diameter of approximately 2 micrometers has a reinforcing aspect ratio of 10.

In addition, the microfiber of this example has a high melting or decomposition temperature (eg, above 800 ° C), a tensile modulus greater than about 50 GPa, and has little or no adhesive coating. Preferably, the microfibers are highly dispersible as discrete filaments, and resistant to the formation of bundles of fibers. Typically, the microfibers will chemically bind to the binder material that is used (eg, organic resin).

In contrast, a fiber of chopped strands and their variations includes a plurality of filaments held together by adhesive and have aspect ratios less than 10. However, some fibers of chopped strands may be ground or otherwise broken to discrete filaments, and such filaments can be used as a microfiber according to an embodiment of the present invention. In some such cases, the resulting filaments can be significantly weakened by the grinding / breakage procedure (eg, due to heating procedures required to remove the adhesive or binder that holds the filaments together in the chopped strand or bundle). Thus, the type of microfiber used in the binder composition will depend on the application in question and the desired strength qualities.

Mineral wool microfibers, in the form of individual filaments, may be present in the compositions and / or tools described herein in an amount within the range of about 0.4 to several volume percent, for example, within the range of about 0.4 to about 12% by volume. Some abrasive articles according to aspects of the invention contain mineral wool microfibers in an amount of about 0.5 to about 10% by volume. In specific implementations, the abrasive article contains mineral wool microfibers in an amount within the range of about 0.8 to about 8 percent by volume, eg, within the range of about 0.8 to about 4% by volume .

In such an embodiment, the microfibers suitable for use in the present invention are mineral wool fibers such as those available from Sloss Industries Corporation, AL, and sold under the name of PMF®. Similar mineral wool fibers are available from Fibertech Inc, MA, under the product designation of Mineral wool FLM. Fibertech also sells fiberglass (eg, Microglass 9110 and Microglass 9132). These glass fibers, as well as other natural or synthetic mineral fibers or individual vitreous filament fibers, such as stone wool, glass and ceramic fibers having similar attributes can also be used. Mineral wool generally includes fibers prepared from minerals or metal oxides. An example composition and a set of properties for a microfiber that can be used in the binder of a reinforced grinding tool, in accordance with an embodiment of the present invention, are summarized in Tables 1 and 2, respectively. Numerous other microfiber compositions and sets of properties will be apparent in light of this description, and it is not intended that the present invention be limited to any particular subset or subset.

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 Oxides

 % in weigh

 Si02

 34-52

 AI203

 5-15

 CaO

 20-23

 MgO

 4-14

 Na20

 0-1

 K20

 0-2

 Ti02

 0-1

 Fe203

 0-2

 Others

 0-7

Table 2: Physical properties of Sloss PMF® fibers

 Hardness

 7.0 mohs

 Fiber diameters

 4-6 micrometers on average

 Fiber length

 0.1-4.0 mm average

 Tensile strength of the fibers

 3,489 MPa (506,000 psi)

 Specific gravity

 2.6

 Melting point

 1,260 ° C

 Temp. devitrification

 815.5 ° C

 Expansion coefficient

 54.7 E-7 ° C

 Annealing point

 638 ° C

 Deformation point

 612

The composition may further include chopped strand fibers, for example fiberglass strand fibers, such as those described above. The chopped strand fibers may have a length of, for example, 3-4 mm, each strand being formed from a plurality of filaments held together by an adhesive known as sizing, binder or coating. The number of filaments and filament diameters may vary depending on the manufacturing process, but typically consists of 400 to 6,000 filaments per bundle, the filament diameters being 10 micrometers or greater. The average reinforcing aspect ratio is less than 3. An example of a chopped strand fiber material that can be used is called 183 Cratec®, available from Owens Corning.

Based on the total volume of the composition or abrasive article, the chopped strand fibers can be added at levels that represent a few percent by volume. Higher or lower levels may be selected based, for example, on desired properties, eg, impact resistance, on the finished abrasive article. In some embodiments, the abrasive article contains the minimum level of chopped strand fibers determined to provide one or more such desired properties. In specific implementations, the chopped strand fibers are present in an amount of about 0.1 to about 10% by volume, for example from about 2 to about 8% by volume, such as from about 3 to about 6% by volume.

The binder materials that can be used in the grinding tool binder configured in accordance with an embodiment of the present invention include organic resins such as epoxy, polyester, phenolic and cyanate ester resins, and other suitable thermosetting or thermoplastic resins. In a particular embodiment, polyphenolic resins (eg, such as Novolaca resins) are used. Specific examples of resins that can be used include the following: resins sold by Durez Corporation, TX, under the following catalog / product numbers: 29722, 29344 and 29717; resins sold by Dynea Oy, Finland, under the trade name Peracit® and available under catalog / product numbers 8522G, 8723G and 8680G; and resins sold by Hexion Specialty Chemicals, OH, under the trade name Rutaphen® and available under the

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catalog / product numbers 9507P, 8686SP and 8431SP. Numerous other suitable binder materials will be apparent in light of this description (eg, rubber), and it is not intended that the present invention be limited to any particular subset or subset.

Abrasive materials that can be used to produce grinding tools configured in accordance with the embodiments of the present invention include commercially available materials, such as alumina (e.g., extruded bauxite, sintered alumina and sintered by sol-gel, fused alumina), silicon carbide and alumina-zirconia grains. Super-abrasive grains such as diamond and cubic boron nitride (cBN) can also be used depending on the given application. In a particular embodiment, the abrasive particles have a Knoop hardness of between 1,600 and 2,500 kg / mm2 and have a size between about 10 millimeters and 3,000 micrometers, or even more specifically, between about 5 millimeters and about 2,000 micrometers. Combinations of two or more types of abrasive grains can also be used. In one case, the composition from which grinding tools are prepared comprises more than or equal to about 50% by weight of abrasive material.

In specific embodiments, the composition further includes one or more active charges, at least one charge being able to chemically react with the microfibers at the temperatures that occur during grinding. In such a case, the active load reactive with the microfibers is selected from: manganese compounds, silver compounds, boron compounds, phosphorus compounds, and any combinations thereof. In specific implementations, the active load used is a manganese compound, eg, a manganese halide, such as, for example, manganese dichloride, complex salts of metal compounds containing manganese, combinations containing one or more compounds of manganese, etc. The amounts of active loading of manganese compound present in the composition and / or abrasive article may be within the range of about 1 to about 10% by volume, eg, within the range of about 2 to about 4% by volume . Other quantities can be used.

Thus, a composition for abrasive articles is provided which includes a mixture of microfibers, eg, mineral wool microfibers, and active fillers. The benefits of the composition include, for example, improvements in both strength and grinding performance.

Other charges that do not chemically react with microfibers can also be incorporated. These additional charges can be added to facilitate dispersion of microfibers or increase grinding performance by conventional mechanisms known to those skilled in the art, such as resin degradation, workpiece degradation, abrasive degradation, anti-load qualities, and lubrication. . Suitable examples include pyrite, zinc sulfide, cryolite, calcium fluoride, potassium aluminum fluoride, potassium fluoroborate, potassium chloride and combinations thereof.

During the manufacture of abrasive articles, the charges are often provided as a "package" of charge, also referred to herein as "component" of charge, which contains a combination of compounds that act as processing aids, to disperse the microfibers, provide lubrication during the pressing cycle, absorb moisture or volatiles during curing, and so on. Such fillers may, for example, reduce friction between a finished abrasive article and a workpiece, protect used abrasive grains, and / or provide other benefits, known in the art. Charging components that can be used in the compositions and / or articles described herein include, for example, lime, pyrites, potassium sulfate (K2S04), potassium chloride (KCI), zinc sulphide, cryolite, calcium fluoride, potassium aluminum fluoride, potassium fluoroborate, combinations thereof, as well as active fillers such as the manganese compounds discussed above, and so on. In some aspects described herein, the charge package does not include potassium salts.

In one implementation, the composition and / or abrasive article includes abrasive grains, an organic binder, mineral wool microfibers that are uniformly dispersed in the organic binder, the mineral wool microfibers being individual filaments, chopped strand fibers, a manganese compound and, optionally, other charges. The composition and / or abrasive article, however, does not include potassium salts such as, for example, potassium sulfate and / or potassium chloride. It has been found that omitting potassium salts in some of the compositions and / or abrasive articles described herein may result in improved grinding performance of the tool, relative to a comparative tool containing potassium sulfate and / or other potassium salts As used herein, the term "comparatives" refers to articles or compositions that are similar to the experimental article or composition in all aspects except the quantity, property, and / or compound or component being investigated.

In specific implementations, the abrasive composition or article includes (based on the total volume of the abrasive composition or article) from about 10 to about 50% by volume, eg, from about 38 to about 41% by volume of organic binder ; from about 30 to about 65% by volume, eg, from about 49 to about 59% by volume of abrasive grain; from about 0.4 to about 12% by volume, eg, from 0.8 to about 8% by volume of mineral wool microfibers; from about 0 to about 10% by volume, for example from about 0.1 to about 10% by volume, eg, from about 2 to about 8 or

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from about 3 to about 6% by volume of chopped strand fibers; and from about 1 to about 10, eg, from about 2 to about 4% by volume active loading of manganese compound.

Optionally, one or more other fillers such as those described above are also present, eg, lime, iron pyrite, potassium sulfate, potassium chloride, and the like. Suitable amounts used can be selected as is known in the art. In some cases, the volume% of potassium salts is 0.

Optionally also, the abrasive composition or article may further include secondary abrasive grains capable of acting as fillers. Examples include silicon carbide, molten brown alumina and others, known in the art.

Some of the abrasive articles described herein may contain abrasive grains, a binder, microfibers that are individual filaments, eg, mineral wool microfibers, an active filler, for example a manganese compound, one or more reinforcements and , opclonally fibers of chopped strands. As used herein, terms such as "reinforced" or "reinforcement" refer to discrete layers or inserts or other components such as a reinforcing material that is different from the binder and abrasive materials used to prepare the bonded abrasive tool. Terms such as "internal reinforcement" or "internally reinforced" indicate that these components are inside or embedded in the tool body. Background details related to reinforcement techniques and materials are described, for example, in US Pat. No. 3,838,543, issued October 1, 1974 to Lakhanl. Reinforced wheels are also described in US Pat. Nos. 6,749,496, issued to Mota, et al. on June 15, 2004 and 6,942,561, issued to Mota, et al. on September 13, 2005.

In many cases, internally reinforced grinding wheels include discs cut from nylon, carbon, glass or cotton cloth. In specific implementations, the abrasive article includes a fiberglass reinforcement that is in the form of a sheet, eg, a material woven from very thin glass fibers, also referred to herein as glass cloth. One, two or more than two such fiberglass sheets can be used, and they can be arranged in the bonded abrasive tool in any suitable manner.

The fiberglass used can be E glass (alumino borosilicate glass with less than 1% by weight of alkali metal oxides). Other types of fiberglass can be used, eg, glass A (alkali-lime glass with little or no boron oxide), glass E-CR (alumino-lime silicate with less than 1% by weight of alkaline oxides, with high acid resistance), glass C (alkali glass with high boron oxide content, used for example for cut glass fibers), glass D (borosilicate glass with high dielectric constant), glass R (alumlnoslllcato glass without MgO and CaO with high mechanical requirements), and S glass (aluminosilicate glass without CaO but with high MgO content with high tensile strength), fiberglass sheets, and so on.

Compositions in the form of abrasive articles may include porosity, eg, at levels suitable for a given application. In specific examples, the porosity is less than 30% by volume, for example within the range of about 2% to about 8% by volume.

Without wishing to be subject to any particular interpretation, it is believed that manganese compounds chemically interact with mineral wool microfibers, providing multiple benefits for the abrasive process, such as, for example, increased tool strength and grinding performance and / or benefits for the life of the tooth. In contrast to chopped strand fibers, the high aspect ratio of microfibers (eg, mineral wool, ground glass or ground basalt) offers an increased surface area, resulting in synergistic reactions with the active load or charges employed The presence of discrete filaments with very low coating levels, together with one or more manganese compounds, provides optimum benefits to the composite material and grinding as opposed to bundles of fibers with high coating levels. Furthermore, it has been observed that the presence of potassium salts such as potassium chloride or potassium sulfate interferes with this "synergistic" interaction of manganese salts and discrete filaments. Abrasive articles containing glass sheet reinforcements, and / or chopped strand fibers, typically show improved impact properties. The combination of mineral wool microfibers that are individual filaments (as opposed to bundles of fibers), preferably in the presence of an active filler, e.g., a manganese compound, with chopped strand fibers (in bundles) and / or Fiber sheet products (reinforcements) provide increased tool strength, increased grinding performance and / or improved tool life, as well as increased impact resistance, decreasing the abrasive article's tendency to break.

Several examples of microfiber reinforced abrasive composite materials are now provided to further show features and benefits of a composite material for an abrasive tool configured in accordance with embodiments of the present invention. In particular, Example 1 shows composite material properties for binder bars and mixing bars with and without mineral wool; Example 2 shows properties of composite material as a function of mixing quality; Example 3 shows grinding performance data as a function of mixing quality; and Example 4 shows the grinding performance based on active loads with and without mineral wool. Example 5 compares the synergistic effects on grinding performance obtained by adding an active charge of a manganese compound to mineral wool microfibers in relation to adding the

active loading of manganese compound to chopped strand fibers. Example 6 shows the grinding performance as a function of active loads with mineral wool microfibers used in combination with glass fibers of chopped strands.

Examples

5 Example 1

Example 1, which includes Tables 3, 4 and 5, shows properties of binder bars and composite bars with and without mineral wool fibers. Note that the binder bars do not contain grinding agent, while composite bars include a grinding agent and reflect a grinding wheel composition. As can be seen in Table 3, the components of eight sample binder compositions (in percent by volume, or% vol) are provided. Some of the binder samples do not include reinforcement (samples Nos. 1 and 5), some include ground glass fibers or chopped strand fibers (samples Nos. 3, 4, 7 and 8), and some include Sloss PMF® mineral wool (samples Nos. 2 and 6) according to an embodiment of the present invention. Other types of individual filament fibers (eg, ceramic or glass fibers) may also be used, as will be apparent in light of this description. Note that the molten brown alumina 15 (grain 220) in the binder is used as a charge in these binder samples, but it can also function as a secondary abrasive (the primary abrasive can be, for example, extruded bauxite, grain 16). Note also that SaranTM 506 is a polyvinylidene chloride binder produced by Dow Chemical Company, molten brown alumina was obtained from Washington Mills.

Table 3: Example binders with and without mineral wool

 Samples -> J Components,

 N ° 1 N ° 2 N ° 3 N ° 4 N ° 5 N ° 6 N ° 7 N ° 8

 Hardness 29722

 48.11 48.11 48.11 48.11 42.09 42.09 42.09 42.09

 Saran 506

 2.53 2.53 2.53 2.53 2.22 2.22 2.22 2.22

 Fused brown alumina - 220 grit

 12.66 6.33 6.33 6.33 18.99 9.50 9.50 9.50

 Sloss PMF®

   6.33 9.50

 Ground fiberglass

     6.33 9.50

 Chopped strand

       6.33 9.50

 Iron pyrite

 20.4 20.4 20.4 20.4 20.4 20.4 20.4 20.4

 Potassium Chloride / Sulfate (mix 60:40)

 9.8 9.8 9.8 9.8 9.8 9.8 9.8 9.8

 Lime

 6.5 6.5 6.5 6.5 6.5 6.5 6.5 6.5

For the set of sample binders 1 to 4 of Table 3, the compositions are equivalent, except for the type of reinforcement used. In samples 1 and 5, where there is no reinforcement, the% in volume of charge (in this case, molten brown alumina) was correspondingly increased. Also, for the set of samples 5 to 8 of Table 3, the compositions are equivalent, except for the type of reinforcement used.

25 Table 4 shows properties of the binder bar (without abrasive agent), including tension and elastic modulus (E-Mod) for each of the eight samples in Table 3.

Table 4: Properties of the binder bar (3-point bending)

 Samples —►

 N ° 1 N ° 2 N ° 3 N ° 4 N ° 5 N ° 6 N ° 7 N ° 8

 Voltage (MPa)

 90.1 115.3 89.4 74.8 103.8 118.4 97 80.7

 Dev. its T. (MPa)

 8.4 8.3 8.6 17 8 6.5 8.6 10.8

 E-Mod (MPa)

 17,831 17,784 17,197 16,686 21,549 19,574 19,191 19,131

 Dev. its T. (MPa)

 1,032 594 1,104 1,360 2,113 1,301 851 1,242

Table 5 shows properties of the composite bar (which includes the binders in Table 3 plus an abrasive, such as extruded bauxite), including tension and elastic modulus (E-Mod) for each of the eight samples of Table 3. As can be seen in each of Tables 4 and 5, the binder / composite material reinforced with mineral wool (samples 2 and 6) has greater resistance in relation to the other samples shown.

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 Samples ->

 N ° 1 N ° 2 N ° 3 N ° 4 N ° 5 N ° 6 N ° 7 N ° 8

 Voltage (MPa)

 59.7 66.4 61.1 63.7 50.1 58.2 34 34

 Dev. its T. (MPa)

 8.1 10.2 8.5 7.2 9.8 4.6 4.4 4.1

 E-Mod (MPa)

 6,100 6,236 6,145 6,199 5,474 5,544 4,718 4,427

 Dev. its T. (MPa)

 480 424 429 349 560 183 325 348

In each of the samples of abrasive composite material 1 to 8, approximately 44% by volume is binder (including the targeted binder components, minus the abrasive), and approximately 56% by volume is abrasive (e.g., extruded bauxite, or other suitable abrasive grain). In addition, a small but sufficient amount of furfural (approximately 1% by volume or less of the total abrasive) was used to wet the abrasive particles. Sample compositions 1 to 8 were mixed with the furfural moistened abrasive grains aged for 2 hours before molding. Each mixture was preweighed, then transferred to a 3-cavity mold (26 mm x 102.5 mm) (1.5 mm x 114.5 mm) and hot pressed at 160 ° C for 45 minutes under 140 kg / cm2, followed after 18 hours of curing in a convection oven at 200 ° C. The resulting composite bars were tested in 3-point flexion (5: 1 depth arc ratio) using the ASTM D790-03 procedure.

Example 2

Example 2, which includes Tables 6, 7 and 8, shows properties of the composite material as a function of mixing quality. As can be seen in Table 6, components of eight sample compositions (in% by volume) are provided. Sample A does not include reinforcement, and samples B to H include Sloss PMF® mineral wool in accordance with an embodiment of the present invention. Other types of single filament microfiber (eg, ceramic fiber or glass) can also be used, as described above. The binder material of sample A Includes silicon carbide (grain 220) as the filler, and the binders of samples B to H use molten brown alumina (grain 220) as the filler. As noted above, such charges help dispersion and can also function as secondary abrasives. In each of samples A to H, the primary abrasive used is a combination of molten brown alumina of grain 60 and grain 80. Note that a single abrasive grain can also be mixed priming with the binder, and may vary in grain size (eg, grain 6 to grain 220), depending on factors such as the desired removal and surface finishing rates.

Table 6: Composite materials of the example with and without mineral wool

 Samples —►

 A B C D E F G H

 J. Components

 Hardness 29722

 17.77 16.88 16.88 16.88 16.88 16.88 16.88 16.88

 Saran 506

 1.69 1.57 1.57 1.57 1.57 1.57 1.57 1.57

 Silicon carbide - 220 grit

 5.92 0.00 0.00 0.00 0.00 0.00 0.00 0.00

 Fused brown alumina - 220 grit

 0.00 3.98 3.98 3.98 3.98 3.98 3.98 3.98

 Sloss PMF®

 0.00 3.81 3.81 3.81 3.81 3.81 3.81 3.81

 Iron pyrite

 10.15 9.64 9.64 9.64 9.64 9.64 9.64 9.64

 Potassium sulfate

 4.23 4.02 4.02 4.02 4.02 4.02 4.02 4.02

 Lime

 2.54 2.41 2.41 2.41 2.41 2.41 2.41 2.41

 Fused Brown Alumina - 60 Grain

 28.5 28.5 28.5 28.5 28.5 28.5 28.5 28.5

 Fused brown alumina - 80 grit

 28.5 28.5 28.5 28.5 28.5 28.5 28.5 28.5

 Furfural

 ~ 1% by weight or less of total abrasive

As can be seen, samples B to H are equivalent in composition. In sample A, where there is no reinforcement, the volume% of other binder components is correspondingly increased as shown.

 Samples ->

 A B C D E F G H

 Mixing method

 Hobart with Hobart blades with Hobart blades with Hobart whisk with blades and Interlator at 6,500 rpm Eirich Interlator at 3,500 rpm Interlator at 6,500 rpm Eirich and Interlator at 3,500 rpm

 Mixing time

 30 minutes 15 minutes N / A 15 minutes

 Mineral wool not dispersed

 N / A 0.9 g 0.6 g 0 0.5 0

Table 7 indicates the mixing procedures used for each of the samples. Samples A and B were each mixed for 30 minutes with a Hobart mixer using shovels. Sample C was mixed for 30 minutes with a Hobart type mixer using a whisk. Sample D was mixed for 30 minutes

with a Hobart type mixer using a shovel, and then processed by an lnterlator (or other suitable hammer mill apparatus) at 6,500 rpm. Sample E was mixed for 15 minutes with an Eirich mixer. Sample F was processed by an Interlator 3,500 rpm. Sample F was processed by an Interlator at 6,500 rpm. The H mixture was mixed for 15 minutes with an Eirich mixer, and then processed by an Interlator at 3,500 rpm. A dispersion test was used to calibrate the amount of mineral wool not

dispersed for each of samples B to H. The dispersion test was as follows: the amount of residue that resulted after 100 grams of the mixture was stirred for one minute using the Rototap method followed by screening through a sieve No. 20. As can be seen, it was observed that sample B had a residue of 0.9 grams of mineral wool that remained in the sieve mesh, sample C a residue of 0.6 grams, and sample E a residue 15 of 0.5 grams. Each of samples D, F, G and H left no significant residual fiber in the screen mesh. Therefore, depending on the desired mineral wool dispersion, various mixing techniques can be used.

Mixing compositions A to H were mixed with furfural moistened abrasive grains aged for 2 hours before molding. Each mixture was preweighed, then transferred to a 3-cavity mold (26 mm x 102.5 mm) (1.5 mm x 114.5 mm) and hot pressed at 160 ° C for 45 minutes under 140 20 kg / cm2, followed after 18 hours of curing in a convection oven at 200 ° C. The resulting composite bars were tested in 3-point flexion (5: 1 depth arc ratio) using the ASTM D790-03 procedure.

Table 8: Means and standard deviations

 Sample

 No. of tests Average Desv. its T. Average of err. its T. Less than 95% Greater than 95%

 TO

 18 77,439 9.1975 2,1679 73.16 81.72

 B

 18 86,483 9.2859 2,1887 82.16 90.81

 C

 18 104,133 10,2794 2,4229 99.35 108.92

 D

 18 126,806 5,9801 1,4095 124.02 129.59

 AND

 18 126,700 5.5138 1.2996 124.13 129.27

 F

 18 127,678 4,2142 0.9933 125.72 129.64

 G

 18 122,983 4.8834 1.1510 120.71 125.26

 H

 33 123,100 6,4206 1,1177 120.89 125.31

Figure 1 is an ANOVA analysis of a composite strength factor for each of samples A to H. Table 8 shows the means and standard deviations. The standard error uses a pooled estimate of error variance. As can be seen, the strength of the composite material for each of samples B to H (each reinforced with mineral wool, according to an embodiment of the present invention) is significantly better than that of sample A not reinforced.

30 Example 3

Example 3, which includes Tables 9 and 10, shows the grinding performance as a function of the mixing quality. As can be seen in Table 9, the components of two sample formulations (in% in

volume). The formulations are identical, except that Formulation 1 was mixed for 45 minutes and Formulation 2 was mixed for 15 minutes (the mixing method used was identical as well, except for the mixing time as noted). Each formulation includes Sloss PMF® mineral wool, in accordance with an embodiment of the present invention. Other types of single filament fiber microfiber (eg, 5 fiberglass or ceramic), described above, can also be used.

Table 9: Grinding performance based on mix quality

 Sequence

 Formulation 1 component (% by volume) Formulation 2 (% by volume)

 Stage 1: Preparation of the binder

 Hardness 29722 22.38 22.38

 Fused brown alumina - 220 grit

 3.22 3.22

 Sloss PMF®

 3.22 3.22

 Iron pyrite

 5.06 5.06

 Zinc sulphide

 1.19 1.19

 Cryolite

 3.28 3.28

 Lime

 1.19 1.19

 Tridecyl alcohol

 1.11 1.11

 Stage 2: Mix

   45 minutes 45 minutes

 Binder Quality Evaluation

 % by weight of mineral wool not dispersed by the Rototap method 1.52 2.36

 Stage 3: Preparation of the composite material

 Abrasive 48 48

 Varcum 94-906

 4.37 4.37

 Furfural

 1% by weight of the total abrasive

 Stage 4: Filling the mold and cold pressing

 Porosity target 8% 8%

 Stage 5: Cured

   30 h ramp up to 175 ° C followed by 17 h stabilization at 175 ° C

As can also be seen from Table 9, the manufacturing sequence of a microfiber reinforced abrasive composite material configured in accordance with an embodiment of the present invention includes five steps: preparation of the binder; mixing, preparation of the composite material; mold filling and cold pressing; and cured An evaluation of the quality of the binder was made after the stages of preparation of the binder and mixing. As discussed above, one way to assess the quality of the binder is to perform a dispersion test to determine the percentage by weight of mineral wool not dispersed by the Rototap method. In this particular case, the Rototap method included adding 50 g-100 g of binder sample to a 40 mesh screen and then measuring the amount of residue in the 40 mesh screen after 5 minutes of Rototap agitation. The abrasive used in both formulations in Stage 3 was extruded bauxite (grain 16). Molten brown alumina (grain 220) is used as a filler in the preparation of the Stage 1 binder, but can function as a secondary abrasive as explained above. Note that Varcum 94-906 is a furfurol-based resol available from Durez Corporation.

20 Table 10 shows the grinding performance of reinforced grinding wheels prepared both from Formulation 1 and Formulation 2, at various cutting speeds, including 0.75, 1.0 and 1.2 s / cutting.

Table 10: Shows grinding performance

 Formulation

 Cut rate (s / cut) MRR cm3 / min (in3 / min) WWR cm3 / min (in3 / min) G Ratio

 Formulation 1

 0.75 516.68 (31.53) 71.28 (4.35) 6.37

 Formulation 1

 1.0 385.75 (23.54) 53.91 (3.29) 7.15

 Formulation 1

 1.2 327.25 (19.97) 42.93 (2.62) 7.63

 Formulation 2

 0.75 518.98 (31.67) 121.59 (7.42) 4.27

5

10

fifteen

twenty

25

30

 Formulation 2

 1.0 389.19 (23.75) 81.28 (4.96) 4.79

 Formulation 2

 1.2 325.77 (19.88) 59.65 (3.64) 5.47

As you can see, the material removal rate (MRR), which is measured in cubic centimeters per minute (cubic inches per minute), of Formulation 1 was relatively similar to that of Formulation 2. However, the wheel wear rate (WWR), which is measured in cubic centimeters per minute (cubic inches per minute), of Formulation 1 is consistently lower than that of Formulation 2. Also note that the G ratio , which is computed by dividing MRR by WWR, of Formulation 1 is consistently higher than that of Formulation 2. Recall from Table 9 that the example binder of Formulation 1 was mixed for 45 minutes, and Formulation 2 was mixed 15 minutes. Therefore, the mixing time has a direct correlation with the grinding performance. In this particular example, the 15-minute mixing time used for Formulation 2 was effectively too short when compared to the improved performance of Formulation 1 and its 45-minute mixing time.

Example 4

Example 4, which includes Tables 11, 12 and 13, shows the grinding performance as a function of active loads with and without mineral wool. As can be seen in Table 11, the components of four sample composites (in% by volume) are provided. Samples of composite material A and B are identical, except that sample A includes chopped strand fiber, and does not include molten brown alumina (220 grit) or Sloss PMF® mineral wool. Sample B, on the other hand, includes Sloss PMF® mineral wool and molten brown alumina (220 grit), and does not include chopped strand fiber. The density of the composite material (measured in grams per cubic centimeter) is slightly higher for sample B in relation to sample A. The samples of composite material C and D are identical, except that sample C includes strand fiber chopped and does not include Sloss PMF® mineral wool. Sample D, on the other hand, includes Sloss PMF® mineral wool and does not include chopped strand fiber. The density of the composite material is slightly higher for sample C in relation to sample D. In addition, a small but sufficient amount of furfural (approximately 1% by volume or less of the total abrasive) was used to wet the abrasive particles, which in this case they were alumina grains for samples C and D and alumina-zirconia grains for samples A and B.

Table 11: Grinding performance based on active loads

 Component

 Composite material content (% by volume)

 A B C D

 Alumina grain

 0.00 0.00 52.00 52.00

 Alumina-zirconia grain

 54.00 54.00 0.00 0.00

 Hardness 29722

 20.52 20.52 19.68 19.68

 Iron pyrite

 7.20 7.20 8.36 8.36

 Potassium Sulfate (K2S04)

 0.00 0.00 3.42 3.42

 K2S04 / KCI (mix 60:40)

 3.60 3.60 0.00 0.00

 MKC-S

 3.24 3.24 3.42 3.42

 Lime

 1.44 1.44 1.52 1.52

 Fused brown alumina - 220 grit

 0.00 3.52 0.00 0.00

 Porosity

 2.00 2.00 2.00 2.00

 Sloss PMF

 0.00 8.00 0.00 8.00

 Fiber of chopped strands

 8.00 0.00 8.00 0.00

 Furfural

 1% by weight of the total abrasive

 Density (g / cc)

 3.07 3.28 3.09 3.06

 Wheel dimensions (mm)

 760x76x203 760x76x203 610x63x203 610x63x203

Table 12 shows tests performed to compare the grinding performance between samples B and D, both of which were prepared with a mixture of mineral wool and the active loading of example manganese dichloride (MKC-S, available from Washington Mills) , and samples A and C, which were prepared with chopped strands in

place of mineral wool.

Table 12: Shows grinding performance

 Test number

 Sample MRR block material (kg / h) WWR (dm3 / h) G ratio (kg / dm3) Improvement percentage

 one

 A Austenitic Stainless Steel 193.8 0.99 196 27.77%

 B

 222.6 0.89 250

 2

 A Ferritic Stainless Steel 210 1.74 121 27.03%

 B

 208.5 1.36 153

 3

 C Austenitic Stainless Steel 833.1 4.08 204 35.78%

 D

 808.8 2.92 277

 4

 C Carbon steel 812.4 2.75 296 30.07%

 D

 784.1 2.03 385

As you can see, grinding wheels prepared from each sample were used to rectify various 5 pieces of work, called blocks. In more detail, samples A and B were tested on blocks prepared from austenitic stainless steel and ferritic stainless steel, and samples C and D were tested on blocks prepared from austenitic stainless steel and carbon steel. As can also be seen in Table 12, using a mixture of mineral wool and manganese dichloride, samples B and D, provided approximately 27% to 36% improvement in relation to samples A and C (prepared with chopped strands in place 10 of mineral wool). This clearly shows improvements in grinding performance due to a positive reaction between mineral wool and the filler (in this case, manganese dichloride). No such positive reaction occurred with the combination of chopped strand and manganese dichloride. Table 13 lists the conditions under which composite materials A to D were tested.

Table 13: Shows the grinding conditions

 Test number

 Grinding power (kw) Block material Block condition

 one

 First road to 120 and followed by 85 Cold austenitic stainless steel

 2

 First path to 120 and followed by 85 Cold ferritic stainless steel

 3

 105 Hot austenitic stainless steel

 4

 105 Hot carbon steel

fifteen

Example 5

Experiments were undertaken to explore the effects of fiber type and MKCS levels on grinding wheel performance. Wheels were prepared as in Example 4 and only differed with respect to the type of fibers and level of MKCS present. Specifically, the wheels included 8% by volume of chopped strand fibers 20 (CSF) (glass) or 8% by volume of mineral wool microfibers (MW). For each category, the level of MKCS was 0 or 3.42% by volume.

As seen in Table 14, the G ratio for wheels containing 8% by volume of CSF was decreased by approximately 10% when MKCS was added (from 330 kg / dm3 with nothing from MKCS to 296 kg / dm3 with MKCS) . An opposite trend was observed with the molars prepared with mineral wool, where adding MKCS resulted in an approximately 20% increase in the G ratio (from 311 kg / dm3 to novels 0 of MKCS to 385 kg / dm3 when 3 was added , 42% by volume of MKCS). This clearly demonstrates that the MKCS interacts differently with the two types of fiber, and that a synergistic effect is obtained by combining MW microfibers with MKCS. No such effect was observed with the MKCS-CSF combination. In contrast, adding MKCS to compositions containing CSF had a negative effect on the G ratio.

5

10

fifteen

twenty

25

30

Table 14: Effects of MKCS levels and fiber types on G relationships

 Fiber type

 G ratio (kg / dm3)

 MKCS level (% by volume)

 0.00

 3.42

 CSF (8% by volume)

 330.00 296.00 (Std.)

 MW (8% by volume)

 311.00 385.00

Example 6

Example 6, which includes Table 15 and Figure 2, shows the grinding performance as a function of the active loads in combination with mineral wool and chopped strand fibers. As can be seen in Table 15, the components of eight sample composites (in% by volume) are provided.

All samples (Exp 1 to Exp 8) included the same type and quantity of abrasive grain. Two levels of fiberglass strands (CSF) of glass fiber were used: a high level of 6% by volume (Exp 1, Exp 2, Exp 5 and Exp 6) and a low level of 4% by volume (Exp 3 , Exp 4, Exp 7 and Exp 8).

In all cases, the binder included resin (organic), microflora of mineral wool (MW) Sloss PMF®, iron compound (pyrite), lime, and the active charge, manganese dichloride (MKCS). The Exp 5 to Exp 8 samples also included potassium sulfate loading, while the remaining samples (Exp 1 to Exp 4) did not include it.

The synergy between mineral wool microfibers and the active loading of manganese compound was particularly significant in samples that had low levels of CSF (fiberglass). As the fiberglass level was increased, the advantage of the MKCS / MW was less pronounced. These results demonstrated that the active loading of manganese compound does not provide the same benefits with respect to glass CSF as it does with MW microfibers.

The data also showed that adding potassium sulfate (Exp 5 to Exp 8) had a detrimental effect on the cumulative G ratio. In general, the values of cumulative Q ratio (defined as removed metal (kg or lbs) / tooth wear (kg or Ibs)) were observed for samples that did not contain potassium sulfate, and this was particularly significant. low levels of CSF (fiberglass). (See, e.g., Exp 3 and Exp 4). Compared to the effects of MKCS, potassium sulfate did not provide an increase in grinding performance, or provided a decreased grinding performance.

The results showed that the grinding performance increased as MKCS and MW were increased, and that the slippery effects observed with these two ingredients did not extend to the fibers of chopped strands of glass fiber or other fillers (e.g., sulfate of potassium). Experiments showed that there is an unexpected performance advantage when the combination of MW and MKCS is used in a grinding wheel.

The data also indicates that potassium salts have an increased effect on performance in compositions that include the highest levels of fiber of chopped glass strands, mineral wool microfibers and a manganese compound, and less effect on compositions that include microfibers. of mineral wool, a compound of manganese and lower levels of chopped strand fibers.

Table 15: Tool performance with MW, CSF and combined loads

 Component

 Composite material content (% by volume)

 1 2 3 4 5 6 7 8

 Grain

 55.5 55.5 55.5 55.5 55.5 55.5 55.5 55.5

 Fiber of chopped strands

 6.0 6.0 4 4 6.0 6.0 4 4

 Binder

 38.5 38.5 40.5 40.5 38.5 38.5 40.5 40.5

 Resin

 19.25 19.48 20.23 20.49 19.25 19.48 20.23 20.49

 Sloss PMF

 1.44 0.97 1.52 1.02 1.25 0.84 1.31 0.88

 MKC-S

 3.65 3.69 3.83 3.88 2.50 2.53 2.63 2.66

 Iron pyrite

 12.66 12.82 13.31 13.48 11.85 11.99 12.46 12.61

 Lime

 1.52 1.54 1.60 1.62 1.15 1.16 1.21 1.22

 Potassium sulfate

 0.00 0.00 0.00 0.00 2.50 2.53 2.63 2.66

 Cumulative Q Ratio

 70.1 68.4 84.0 71.4 69.4 65.4 68.0 55.3

Claims (15)

5 10 fifteen twenty 25 30 35 40 Four. Five 1. An abrasive article, comprising: an organic binder material; an abrasive material, dispersed in the binder organic material; chopped strand fibers dispersed in the binder organic material, the pounds of chopped strands comprising about 0.1% by volume to about 10% by volume in the abrasive article; mineral wool microfibers that are uniformly dispersed in the binder organic material, wherein said microfibers are individual filaments; Y one or more charges, including the one or more charges a manganese compound. 2. The abrasive article of claim 1, wherein the manganese compound is manganese dichloride, and 2% by volume to 8% by volume fibers of chopped strands in the abrasive article. 3. The abrasive article of claim 1, wherein the manganese compound is present in the abrasive article in an amount within the range of about 1 to about 10% by volume. 4. The abrasive article of claim 1, wherein the mineral wool microfibers are present in the abrasive article in an amount within the range of about 0.5 to about 10% by volume. 5. The abrasive article of claim 1, wherein the abrasive article does not include potassium salts. 6. The abrasive article of claim 1, wherein the chopped strand fibers are chopped strand fiberglass fibers, and the abrasive article includes one or more glass sheet reinforcements. 7. The abrasive article of claim 1, wherein the mineral wool microfibers have a reinforcing aspect ratio of at least 10 and the chopped strand fibers have an aspect ratio less than 3. 8. The abrasive article of claim 1, wherein the abrasive article includes: from 25% by volume to 40% by volume of the organic binder material; from 50% by volume to 60% by volume of the abrasive material; from 0.5% by volume to 10% by volume of microfibers; from 3% by volume to 6% by volume of chopped strand fibers; and from 1% by volume to 10% by volume of manganese compound. 9. A method for abrasively processing a workpiece, the method comprising: mount the workpiece on a machine capable of facilitating abrasive processing; operatively coupling an abrasive article to the machine, the abrasive article comprising an organic binder material; an abrasive material dispersed in the binder organic material; chopped strand fibers dispersed in the binder organic material comprising from 0.1% by volume to 10% by volume of the abrasive article; mineral wool microfibers, uniformly dispersed in the binder organic material, wherein said microfibers are individual filaments; Y one or more charges, including the one or more charges a manganese compound; and contacting the abrasive article with a surface of the workpiece. 10. The method of claim 9, wherein the manganese compound is manganese dichloride, and the abrasive article does not include potassium salts. 11. The method of claim 9, wherein the manganese compound is present in the abrasive article in an amount within the range of about 1 to about 10% by volume, and from 2% by volume to 8% by volume fibers of chopped strands in the abrasive article. 12. The method of claim 9, wherein the mineral wool microfibers are present in the abrasive article in an amount within the range of about 0.5 to about 10% by volume. 13. The method of claim 9, wherein the chopped strand fibers are chopped strands of fiberglass fibers, and the abrasive article includes one or more glass sheet reinforcements. 14. The method of claim 9, wherein the mineral wool microfibers have an aspect ratio reinforcer of at least 10 and chopped strand fibers have an aspect ratio less than 3. 15. The method of claim 9, wherein the abrasive article includes: from 25% by volume to 40% by volume of the organic binder material; from 50% by volume to 60% by volume of the abrasive material; from 0.5% by volume to 10% by volume of microfibers; from 3% by volume to 6% by volume of chopped strand fibers; and from 1% 5 by volume to 10% by volume of manganese compound.