WO2005072913A1 - Abrasive tools of composite materials and methods of making the same - Google Patents

Abstract

An abrasive composite material that includes a polymer layer comprising one or more polyarylene sulfides, particularly polyphenylene sulfide, and a plurality of abrasive particles at least partially embedded in the polymer layer. The composite material has enhanced strength and flexibility, and the abrasive particles are held in place within the polymer layer without the need for an additional bonding material. Abrasive tools manufactured from the composite material according to various embodiments of the invention have surprisingly high material removal rates, as well as enhanced durability and mechanical strength.

Description

ABRASIVE TOOLS OF COMPOSITE MATERIALS AND METHODS OF MAKING THE SAME CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to and the benefit of U.S. Patent Application Serial No. 10/765,365 filed January 27, 2004, as well as U.S. Provisional Application Serial No. 60/562,098 filed April 14, 2004, the entire disclosures of both applications being incorporated herein by reference.

FIELD OF THE INVENTION [0002] The present invention relates generally to the field of abrasive composite materials. More particularly, the invention relates to composite materials comprising polyarylene sulfide polymers with abrasive particles dispersed therein, as well as to abrasive tools manufactured using such materials.

BACKGROUND OF THE INVENTION [0003] Conventional sheet abrasives and other abrasive elements generally include abrasive particles bonded to the surface of a paper or cloth base material. These types of coated sheet abrasives, however, suffer from several disadvantages. Typically, a coated sheet abrasive contains a single layer of abrasive particles coated on the base material, which itself is non-abrasive. During use, the abrasive particles are either worn down or become detached from the surface of the base material, leaving only bare base material in contact with the work surface. Thus, the useful life of these types of sheet abrasives is limited by the thickness of the abrasive particle layer and by the strength of the bond between the abrasive particles and the base material. In addition, the flexibility of conventional coated sheet abrasives is limited because bending or stretching the sheets can dislodge the abrasive particles from the base material and crack, crease, or otherwise damage the sheet. [0004] Also known are sheet abrasives made of abrasive particles dispersed within a polymer. In some cases, these sheets are formed by mixing the abrasive particles and the polymer in an organic solvent, and subsequently evaporating the solvent. Storing, handling, and transporting the organic solvents used in this process pose a significant inconvenience and health hazard to operators. Furthermore, evaporating the organic solvents can make the process more costly and time consuming. In other cases, abrasive particles are mixed with a polymer in solid form, and the mixture is compression molded to form a pad with a plurality of abrasive protrusions. The compression molding process is time consuming because the process in non-continuous, i.e., each mold can only produce one abrasive pad at a time. [0005] Abrasive tools, such as sheets, strips or straps, manufactured using thermoplastic abrasive composite materials that include a granular abrasive material embedded homogeneously throughout a thermoplastic polymer have been disclosed in, for example, U.S. Patent Nos. 5,129,197; 5,155,945; 5,170,593; 5,187,904; 5,279,079; 5,318,603; 5,423,718; and 6,379,238. The abrasive material usually comprises about 30 to 45% by weight of the composite material. In addition, thermoplastic abrasives manufactured from nylon monofilaments having abrasive grains homogeneously embedded therein are presently commercially available, for instance from Specialty Filaments, Inc. of Andover, MA. Abrasive composites based on conventional thermoplastic materials, such as nylon, however, perform poorly in many applications involving abrading or cutting of metals, particularly hard metals and alloys, such as stainless steel.

[0006] Further, conventional brushes used for sanding, polishing, or otherwise acting on a work surface are typically produced by attaching abrasive bristles to a suitable substrate. The bristles are generally time consuming and expensive to produce, as is the process of attaching the bristles to the substrate. In the case of floor care and metal finishing brushes, the point of attachment between the bristles and the substrate is an area of stress concentration that often leads to bristle breakage at the base of the brush during use, which can damage the work surface. Furthermore, the bristles are not readily replaced when worn out, which precludes reuse of the brushes. [0007] Also known in the art are rotary abrasive tools that include a plastic strap or tape having granular abrasive particles embedded homogeneously throughout. Each strap or tape is secured to a central rotatable hub through relatively complex wire, strap and adhesive constructions. [0008] Therefore, there is a need in the art for flexible sheet abrasives and other abrasive elements having increased durability and mechanical strength that can be produced in an efficient, cost-effective manner and can be incorporated into reusable abrasive tools.

SUMMARY OF THE INVENTION [0009] In general, in one aspect, the present invention is directed to an abrasive composite material that includes a polymer layer comprising one or more polyarylene sulfides, particularly polyphenylene sulfide (PPS), and a plurality of abrasive particles at least partially embedded in the polymer layer. The composite material has enhanced strength and flexibility, and the abrasive particles are held firmly in place within the polymer layer without the need for an additional bonding material. The abrasive composite materials of the invention are useful in discrete sheet form and can also be used to make any of the conventional abrasive tools, for instance, discs, flapwheels, and belts. Abrasive tools manufactured from the composite material according to various embodiments of the invention have surprisingly high cut rates and enhanced durability and mechanical strength when compared to nylon-based and other conventional thermoplastic abrasive composites, as well as commercially available non-woven coated abrasives, such as Scotch Brite^tm multi-flex abrasive sheet available from 3M Company of St. Paul, MN. [0010] In various embodiments of the invention, the abrasive particles are granular and include, but are not limited to, silicon carbide, aluminum oxide, diamond, ceramic aluminum oxide, ceramic, zirconia aluminum, garnet, cubic boron nitride, talc, and combinations thereof. In some embodiments, the abrasive particles are dispersed substantially uniformly within the polymer layer. The abrasive particles may comprise from about 1% to about 40% by volume of the polymer layer. In certain embodiments of the invention, the polymer layer of the abrasive composite material is shaped to form a sheet abrasive having thickness ranging from about 0.010 inches to about 0.125 inches, preferably, from about 0.025 inches to about 0.060 inches. In some embodiments, the polymer layer may comprise foamed polymer.

[0011] In some embodiments of the invention, the abrasive composite material contains an auxiliary polymer layer, adjacent to the layer comprising one or more polyarylene sulfides and abrasive particles. The auxiliary layer may also comprise at least one polyarylene sulfide, for example, polyphenylene sulfide, and may contain a plurality of abrasive particles at least partially embedded therein. An adhesive layer may be disposed between the polyarylene sulfide layer and the auxiliary layer. In various embodiments of the invention, the polymer layer and/or the auxiliary layer include polyamides, polyurethanes, acetals, thermoplastic polyimides, liquid crystal polymers, polyetheramides, polyetheresters, polyethylene, or combinations thereof.

[0012] In general, in further aspects, the present invention features methods of forming abrasive composite materials that include the steps of providing a volume of molten polymer material comprising one or more polyarylene sulfides, particularly, polyphenylene sulfide, dispersing a plurality of abrasive particles in the volume of the polymer material and causing the polymer material having the plurality of abrasive particles at least partially embedded therein to assume a predetermined shape, for example, by either extruding or molding the resulting mixture. The extruded composite material can be oriented either uni-axially or bi- axially, for example, by stretching. Composites materials of the invention can be formed into various shapes, such as a sheet, a strip, a continuous belt, a flap wheel, and a disc.

[0013] In a particular embodiment, a volume of polyarylene sulfide polymer is combined with granular abrasive material, heated above the melting point of the polymer, and extruded through a conventional sheet extrusion die. The extrudate is solidified and conveyed to a collection system. The collection system can be a winder, which collects the product on rolls, or it can be a cutter to cut the extrudate into discrete lengths. The rolls or lengths can then be processed into a variety of shapes and formed into a variety of tools. [0014] The abrasive composite material may also include an auxiliary layer disposed adjacent to the polymer layer. The auxiliary layer can be co-extruded with the polymer layer, or be adhered thereto with an adhesive. Alternatively, the auxiliary layer can be co-molded with the polymer layer, or the auxiliary layer can be present within the mold prior to injecting the molten polymer material therein. Finally, the auxiliary layer can be adhered to the molded polymer layer with or without an adhesive.

[0015] In general, in still another aspect, the present invention features an abrasive element that includes a base and one or more flaps extending from and integrally formed with the base. The base and the flaps include an abrasive composite material comprising a plurality of abrasive particles at least partially embedded within a polymer layer comprising one or more polyarylene sulfides, for example, polyphenylene sulfide. The base of the abrasive element may have a larger cross-sectional width than the flap. The flap may include first and second ends, where the first end has a larger cross-sectional width than the second end. In these embodiments, the flap may taper from the first end to the second end.

[0016] An alternative embodiment of the abrasive element includes a flap having first and second ends. The flap is made of an abrasive composite material comprising a plurality of abrasive particles at least partially embedded within a polymer layer comprising one or more polyarylene sulfides, for example, polyphenylene sulfide, with the first end of the flap having a larger cross-sectional width than the second end.

[0017] The present invention also provides methods of forming abrasive elements of the invention that include the steps of dispersing a plurality of abrasive particles in a volume of a molten polymer and causing the resulting mixture to assume a predetermined shape, for example, by either extruding the volume of the resulting mixture to form an extruded abrasive element or molding the resulting mixture to form a molded abrasive element. Either compression or injection molding may be used to form the molded abrasive elements.

[0018] The invention also features abrasive tools that include one or more abrasive elements of the invention and a support that contains one or more connecting structures for associating the bases of the abrasive elements with the support. The flaps of the one or more abrasive elements extend away from a surface of the support. The support may be planar, for example, circular. Alternatively, the support may be cylindrical. The support may be adapted to rotate about a rotational axis. The connecting structure may include one or more grooves or raised ridges on a surface of the support. The tool may also contain a retaining structure for maintaining contact between the connecting structures and the one or more abrasive elements, such as, for example, a retaining ring.

BRIEF DESCRIPTION OF THE DRAWINGS [0019] The invention is pointed out with particularity in the appended claims. The invention can be better understood by reference to the description taken in conjunction with the accompanying drawings. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the drawings, like reference characters generally refer to the same parts throughout the different views.

[0020] FIG. 1A is a schematic cross-sectional view of a sheet abrasive comprising an abrasive composite material according to one embodiment of the invention.

[0021] FIG. 1 B is a schematic cross-sectional view of the sheet abrasive of FIG. 1A after using it to abrade a work surface.

[0022] FIG. 2 is a schematic cross-sectional view of a sheet abrasive comprising an abrasive composite material according to another embodiment of the invention. [0023] FIG. 3 is a schematic representation of an embodiment of an extruder suitable for producing abrasive elements comprising an abrasive composite material according to various embodiments of the invention.

[0024] FIG. 4 is a schematic cross-sectional view of a multi-layer sheet abrasive comprising an abrasive composite material according to yet another embodiment of the invention.

[0025] FIGS. 5A and 5B are schematic cross-sectional views of embodiments of abrasive elements that include a base and a plurality of flaps.

[0026] FIG. 6 is a schematic cross-sectional view of another embodiment of an abrasive element that includes a base and a flap.

[0027] FIGS. 7A and 7B are schematic cross-sectional views of other embodiments of abrasive elements that include a base and a flap.

[0028] FIG. 8 is a schematic cross-sectional view of yet another embodiment of an abrasive element that includes a base and a flap. [0029] FIG. 9 is a schematic cross-sectional view of an embodiment of an abrasive element that includes a flap.

[0030] FIGS. 10A and 10B are perspective views of abrasive elements that include a base and a flap.

[0031] FIGS. 11 A and 11 B are schematic cross-sectional views of embodiments of abrasive elements that include a base, a reinforcing member, and a flap.

[0032] FIG. 12A is a perspective view of an embodiment of an abrasive tool that includes a planar support and a plurality of abrasive elements.

[0033] FIG. 12B is a side view of the abrasive tool of FIG. 12A.

[0034] FIG. 13 is a perspective view of another embodiment of an abrasive tool that includes a planar support and a plurality of abrasive elements.

[0035] FIG. 14 is a perspective view of an embodiment of an abrasive tool that includes a cylindrical support and a plurality of abrasive elements. [0036] FIGS. 15A and 15B are schematic cross-sectional views of embodiments of supports that include connecting members. [0037] Fig. 16 is a plot representing the results from the experiment comparing metal removal rates of the sheet abrasive, manufactured from an abrasive _, composite material according to one embodiment of the invention, with the Scotch-Brite™ A CRS product.

DETAILED DESCRIPTION OF THE INVENTION [0038] Throughout the description, where compositions are described as having, including, or comprising specific components, or where processes are described as having, including, or comprising specific steps, it is contemplated that compositions of the invention also consist essentially of, or consist of, the recited components, and that the processes of the invention also consist essentially of, or consist of, the recited steps. [0039] Referring to FIG. 1A, in various embodiments of the invention, a sheet abrasive 2 is formed from an abrasive composite material that includes a plurality of abrasive particles 4A, 4B at least partially embedded within a polymer layer 6. The abrasive particles can be dispersed substantially uniformly throughout the thickness of the polymer layer, or they can be dispersed in a non-uniform fashion. For example, in some embodiment, the concentration of abrasive particles may be greater near one or more surfaces of the polymer layer. [0040] With continued reference to FIG. 1A, a portion of the plurality of abrasive particles may be located at or near a surface 8 of the polymer layer 6 (e.g., abrasive particle 4A) with other abrasive particles located in the interior 10 of the polymer layer 6 (e.g., abrasive particle 4B). Preferably, some of the particles disposed proximate to the surface 8 of the polymer layer 6 are exposed. In some embodiments, during use, friction between the surface of the sheet abrasive manufactured from the abrasive composite material and a work surface wears away portions of the polymer layer and any abrasive particles embedded therein. Referring now to FIG. 1 B, as the polymer layer 6 is worn away, the abrasive particle 4B that was previously in the interior 10 of the polymer layer 6 is exposed. Thus, unlike conventional coated sheet abrasives, whose utility greatly decreases once their topmost abrasive layers have worn away, sheet abrasives, as well as other abrasive tools, manufactured from composite materials according to various embodiments of the invention, maintain their abrasive qualities after portions of the polymer layer are worn away, thereby increasing the useful life of the sheet abrasive or other abrasive tool.

[0041] In some embodiments of the abrasive composite material, abrasive particles 4A, 4B are located at more than one surface of the polymer layer 6. For example, in the illustrative embodiment shown in FIG. 2, the abrasive particle 4A is located at one surface 8 of the polymer layer 6, and the abrasive particle 4C is located at the other surface 12. Another abrasive particle 4B is located in the interior 10 of the polymer layer 6. In this embodiment, both surfaces 8, 12 of the sheet abrasive 2 can be used to abrade one or more work surfaces. [0042] In various embodiments of the invention, the polymer layer is at least partially formed from one or more polyarylene sulfide polymers. As skilled artisans would appreciate, polyarylene sulfide polymers include a repeating unit -(Ar-S-)-, wherein Ar is a substituted or unsubstituted arylene group. The arylene group may comprise, for example, p-phenylene, m-phenylene, o-phenylene, p,p'-biphenylene, p,p'-diphenylene sulfone, p,p'-diphenylene carbonyl, p,p'-diphenylene ether, a naphthalene, or a substituted phenylene

wherein Y_n is alkyl, preferably CrC₆ alkyl, or phenyl, and n is an integer of 1 to 4.

[0043] The polyarylene sulfide may comprise a homopolymer or copolymer (inclusive of terpolymers and higher polymers) of polyarylene sulfide units. Thus, the expression "polyarylene sulfide" as used herein includes not only homopolymers of arylene sulfide units, but also copolymers including such units. The polyarylene sulfide is preferably linear and may be cross-linked.

[0044] In a particular embodiment of the invention, the polyarylene sulfide is polyphenylene sulfide. Thus, the term "polyphenylene sulfide" includes not only homopolymers of phenylene sulfide units, but also copolymers including phenylene sulfide units. Copolymers may comprise two or more different arylene sulfide units, such as p-phenylene sulfide and m-phenylene sulfide. In a preferred embodiment of the invention, the polyarylene sulfide is a substantially linear homopolymer comprising p-phenylene sulfide as the repeating unit, or a copolymer comprising at least about 50 mol %, more preferably at least about 70 mol %, p- phenylene sulfide units. The comonomer is preferably m-phenylene sulfide.

[0045] In some embodiments, one or more polymer layers of the abrasive composite material in accordance with the invention, in addition to polyarylene sulfides, may also include in a combination, blend or alloy of one or more of the thermoplastic polymers known in the art, such as, for example, polyamides, polyesters, polyoxymethylenes, polyethylene, ethylene copolymers, ethylene acrylic acid copolymers, ethylene acrylate copolymers, ethylene methacrylic acid copolymers, ethylene vinyl alcohol copolymer, ethylene vinyl acetate copolymers, polyphenylene ether, polyphenylene oxide, polyphthalamide, polystyrene, polyacrylonitrile, polyurethanes, rubbery polymers (such as, for example, ethylene propylene rubbers and ethylene propylene diene rubbers), polyvinyl chloride, styrene acrylonitrile, acrylonitrile butadiene styrene, styrene butadiene, styrene maleic anhydride, polycarbonate, polyurethanes, acetals, acrylics, cellulosics, cellulose acetate butyrate, cellulose acetate propionate, fluoropolymers (such as, for example, polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), chlorotrifluoroethylene (CTFE), and polytetrafluoroethylene (PTFE)), ionomers, liquid crystal polymers, polyamide imide, thermoplastic polyimides, polyarylate, polybutylene, polyaryletherketone, polyetherether ketone, polyetherketones, polyetherimides, polyethersulfone, polysulfone, thermoplastic elastomers, polyetheramides, polyetheresters, diallyl phthalate, melamine phenolic, phenolics, and unsaturated polyesters. Such polymer blends or alloys can include one or more polymers suspended in another polymer, one or more polymers dissolved in another polymer, or a mixture of suspended and dissolved polymers. In one embodiment, the polymer layer may include a blend of a thermoplastic polymer, such as polyaryelene sulfide, and a polydimethylsiloxane polymer. The blends or alloys can be miscible or immiscible. Abrasive composite materials according to various embodiments of the invention can also be formulated such that the polymer layer can be subsequently cross-linked or cured in a secondary operation, if desired, in order to maximize certain properties such as heat resistance, toughness or elasticity.

[0046] In some embodiments, one or more polymer layers is foamed. Foaming makes the polymer material lightweight and shock-absorptive. One method for foaming a polymer is by the addition of one or more blowing agents to the polymer prior to forming an abrasive composite material. A blowing agent is a solid or a fluid that causes bubbles, for example, gas bubbles, to form within the polymer, which expand as the molten polymer cools. Examples of blowing agents include foaming agents such as Foamazol^® 72 and Foamazol^® XO-227, both available from Bergen International of Rochelle Park, New Jersey. Gaseous blowing agents include inert gases such as nitrogen and argon.

[0047] Abrasive particles suitable for use in the abrasive composite material according to various embodiments of the invention generally have a Knoop scale hardness value greater than any polymer component of the composite material, particularly polyarylene sulfide. Suitable abrasive particles include, for example, aluminum oxide, silicon carbide, zirconia alumina, ceramic aluminum oxide, natural and artificial diamond, glass beads, talc, calcium oxide, clay, ceramic, fiberglass, silica, wood fillers, nut shells, apatite, feldspar, tool steel, quartz, chromium, zirconium carbide, alumina, beryllium carbide, titanium carbide, aluminum boride, cubic boron carbide, cubic boron nitride, emery, spinel, flint, and mixtures thereof. In addition, aggregates or multiple abrasive particles fused together by a bonding agent can be used. In a particular embodiment, a suitable mixture of abrasive particles is a mixture of silicon carbide and aluminum oxide.

[0048] The abrasive particles may be partially or completely coated with an inorganic or metallic coating material, such as, for example, nickel-coated diamond and copper-coated diamond. The abrasive particles may also be coated with coupling agents to increase the adhesion of the abrasive particles to the polymer layer. One example of a class of useful coupling agents is any of a variety of silane coupling agents, for example, 3-aminopropyl-triethoxysilane.

[0049] The abrasive particles can have any size or shape, although preferably the abrasive particles are small enough to be contained entirely within the thickness of the polymer layer. In various embodiments of the invention, abrasive particles are granular. Mixtures of different sized of abrasive particles can be used, such as, for example, a mixture of 46 mesh and 120 mesh silicon carbide.

[0050] The abrasive particles may comprise from about 1% to about 50% by volume of the polymer layer within which they are at least partially embedded, for example, up to 25% by volume, or, more preferably, up to 35% or 45% by volume. In certain embodiments, the amount of abrasive particles in one or more layers of the abrasive composite material may be higher than 50% by volume depending on the particular characteristics of the abrasive particles and/or the polyarylene sulfide, and possibly other polymers, used to form the composite material.

[0051] In addition to the abrasive particles, one or more additives known in the art can be included in one or more polymer layers of the abrasive composite material, such as lubricants, colorants, toughening agents, plasticizers, fillers reinforcements, anti-blocking compounds, process aids, stabilizers and foaming agents. Examples of lubricants include mineral oils, silicone oils, other processing oils, polydimethyl siloxane polymers, fluoropolymers, fluoropolymer oils, molybdenum disulfide, metal stearate salts, fatty amide lubricants, and other lubricants commonly used in polymer compositions and abrasives. [0052] The one or more polymer layers of the abrasive composite material of the invention can be produced by any conventional polymer processing methods, including molding and extrusion. It should be understood that in any of the methods described, the steps can be performed in any order, or one or more steps can be performed simultaneously, as long as the method remains operable.

[0053] In some embodiments, abrasive elements of various shapes are produced by extrusion. For example, abrasive elements in a shape of a monofilament or a sheet of any length can be produced, and then can be cut into discrete lengths or else wound onto rolls. The extrusion process generally involves adding one or more base polymer materials, abrasive particles, and any additional polymers and/or additives into a melt-mixing device to form an abrasive composite material. The material is then transported through the extrusion device, for example, using a screw, toward a die (which has an orifice in the desired shape). As the base polymer material moves through the device it softens and melts and at least one polymer layer is intimately mixed with the abrasive particles and other components. The mixture is then forced through a die, yielding a polymer extrudate. The extrudate is then quenched or solidified, typically using a rollstack sheet quenching device. Alternatively the extrudate may be quenched in water or air. Additional finishing steps may include removing excess water, applying coatings (anti-static, lubricants, etc) and driving the extrudate through rolls or belts to control the sheet speed. It is then wound onto rolls or cut into desired shapes or lengths.

[0054] Referring to FIG. 3, in a particular embodiment, the polymer material including one or more polyarylene sulfides is added to the rear of an extruder 30 through a primary feeder 32, and the abrasive particles are added through a secondary feeder 34. Examples of suitable extrusion devices include single screw extruders, twin screw extruders, Brabender type mixers, and kneaders, some of which are commercially available from Battenfeld Gloucester (Gloucester, Massachusetts) and Davis Standard (Pawcatuck, Connecticut). The surfaces of the extruder and other processing equipment that come into contact with the extrudate can be modified with wear resistant surfaces or liners to reduce wear and increase the useful life of the extruder. The components are transported through the extruder 30 toward a die 38, for example, a standard 6-inch film type die 38 with an adjustable die gap available from Extrusion Dies Inc. of Chippewa Falls, Wisconsin. The mixture is then forced through the die 38, yielding a polymer extrudate 36. In one version of this embodiment, the die gap is set at 0.058 inch for all examples. The extrudate 36 exits a die 38 vertically downward into a water quench bath 40 where the extrudate 36 is solidified. The extrudate 36 is pulled by a set of slow group orientation rolls 42, and passed through an orientation oven 44 and then onto a set of fast group orientation rolls 46. Next, the extrudate 36 is passed through a relaxation oven 48, a set of crimp rolls 50 to provide crimp, and then through a set of lube rolls 52 coated with a lubricant. The extrudate 36 then is passed onto a set of relaxation group rolls 54, which are typically set at the same speed as the fast group orientation rolls 46. Finally, the extrudate 36 is wound onto a collection reel 56.

[0055] In some embodiments, after the abrasive composite material is extruded to form a sheet abrasive or other abrasive element and quenched or solidified, it is subjected to an orientation process to increase the tensile strength of the sheet abrasive. Orientation generally involves stretching or compressing the sheet abrasive at a temperature above the glass transition temperature of the polymer or polymers therein, but below the crystalline melting temperature. Orientation can be uni-axial, typically by stretching or compressing the sheet abrasive along its length (i.e. , in the casting machine direction), or bi-axial, typically by also stretching or compressing the sheet abrasive in a transverse direction (i.e., in a cross machine direction). Bi-axial orientation is typically done using a tenter frame or compression or nip rolls. In some embodiments, the entire sheet abrasive can be oriented, while in other embodiments, one or more portions or layers of the sheet abrasive are oriented and other portions or layers are not. Suitable equipment for orienting sheet abrasives is commercially available from Marshall and Williams Plastics of Woonsocket, Rhode Island, Battenfeld Gloucester of Gloucester, Massachusetts, and Davis Standard of Pawcatuck, Connecticut.

[0056] The rolls or lengths of the abrasive composite material can then be processed into a variety of shapes and formed into a variety of abrasive tools, such as those discussed in United States Patents: 5,129,197; 5,155,945; 5,170,593; 5,187,904; 5,279,079; 5,318,603; 5,423,718; and 6,379,238, all incorporated herein by reference. As one specific example, discs can be formed and attached to threaded inserts for use in powered tools.

[0057] In some embodiments, sheet abrasives and other abrasive elements can be formed from the abrasive composite material of the invention by compression or injection molding. In a compression molding process, a polymer is placed into a mold, which is subsequently closed and held at a high pressure. The mold is heated to fuse the thermoplastic polymer, and after an appropriate time, the mold is opened and the product removed. In contrast, injection molding involves injecting a molten thermoplastic polymer into a closed mold. The molten polymer cools and hardens into shape within the mold, which then is opened to remove the product. Any materials and methods used in compression or injection molding known in the art may be used to form sheet abrasives in accordance with the invention. [0058] The cross-sectional shape of abrasive elements, such as monofilaments or sheet abrasives, manufactured from the composite material of the invention can be tailored to suit their particular applications. For abrasive elements produced by an extrusion process, the cross-sectional shape is determined by the shape of the extrusion die. For a molding process, the shape of the mold determines the cross-sectional shape of abrasive material. In either process, the cross-sectional shape can be further modified by thermal, chemical, and/or mechanical means after the polymer layer or layers of the abrasive composite material has or have been extruded or molded.

[0059] In some embodiments, the abrasive element is a sheet abrasive having the shape of a film, strip, or tape, i.e., its width and length are greater than its thickness. In some embodiments, the sheet abrasive has a width of from about 3 - to 1000 or more times its thickness. However, sheet abrasives can be formed into any shape to adapt to any particular application, for example, a block or o-ring shape. A sheet abrasive can have any cross-sectional shape, including, for example, quadrilateral, round, and oval.

[0060] In various embodiments, a sheet abrasive manufactured from the abrasive composite material according to various embodiments of the invention has thickness ranging from about 0.0005 inch to about 0.25 inch. In certain embodiments, the sheet abrasive has thickness ranging from about 0.001 inch to about 0.25 inch, preferably from about 0.010 inch to about 0.125 inch and even more preferably from about 0.025 inches to about 0.060 inches. In other embodiments, the sheet abrasive has thickness ranging from about 0.001 inch to about 0.05 inch, preferably from about 0.005 inch to about 0.03 inch.

[0061] In the illustrative embodiment shown in FIG. 4, a sheet abrasive 20 includes an auxiliary layer 22 adjacent to a polymer layer 24, which comprises one or more polyarylene sulfides and a plurality of abrasive particles 26 at least partially embedded therein. The auxiliary layer can serve to enhance various properties of the abrasive tool, such as sheet abrasive, including, for example, stiffness, toughness, resilience, abrasion resistance, coefficient of friction, heat stability, chemical resistance, hydrolysis resistance, oxidative stability, heat conductivity, anti-static properties, electrical conductivity, and/or thermal coefficient of expansion. The auxiliary layer can be made of any material, including, for example, paper, cloth, metal, polymer, or combinations thereof. The auxiliary layer can have various forms, including, for example, a continuous sheet, a fibrous woven or non-woven belt, a web or mesh, or a layer of abrasive particles.

[0062] Suitable metals for use in the auxiliary layer include, for example, aluminum, chromium, steel, and alloys thereof. Any of the polymers or combination of polymers described above in connection with the polymer layer can be used to form the auxiliary layer. In addition, the auxiliary layer can include any of the abrasive particles and/or additives described above. In some embodiments, the auxiliary layer contains the same type and/or amount of abrasive particles and /or additives as one or more polymer layers in the abrasive composite material of the present invention. In other embodiments, the auxiliary layer and one or more polymer layers in the abrasive composite material of the present inventioncontain different types and/or amounts of abrasive particles and/or additives.

[0063] The auxiliary layer can be bonded to the polymer layer using an adhesive, or the auxiliary layer can be coated or sprayed onto to the polymer layer. In cases where the auxiliary layer includes a polymer, the auxiliary layer can be extruded onto the polymer layer, or the auxiliary layer and an extruded thermoplastic polymer layer can be co-extruded. A co-extrusion process involves extruding two or more layers simultaneously by combining the extrudates from multiple extruders into a manifold and extruding through a special multi-layer die. Alternatively, the auxiliary layer can be present within a mold prior to injecting a molten layer into the mold. Each layer can have the same or different widths, and the layers may be offset.

[0064] The auxiliary layer can have the same thickness as the polymer layer comprising one or more polyarylene sulfides and a plurality of abrasive particles embedded therein, or the two layers can have different thicknesses. That is, the polymer layer can have a thickness greater than the thickness of the auxiliary layer, or the polymer layer can have a thickness less than the thickness of the auxiliary layer. The auxiliary layer and the polymer layer can have the same shape and/or size, or their shapes and/or sizes may differ. In some embodiments, the auxiliary layer and the polymer layer are aligned so that the auxiliary layer is adjacent to substantially all of a surface of the polymer layer. In other embodiments, the auxiliary layer and the polymer layer are offset, so that at least one portion of the polymer layer is not adjacent to the auxiliary layer. This embodiment is particularly useful for abrasive composite materials that are extruded and wound into rolls. [0065] The present invention also contemplates abrasive tools that contain further layers in addition to the auxiliary layer and the polymer layer comprising one or more polyarylene sulfides and a plurality of abrasive particles embedded therein. The additional layers can be disposed adjacent to any other layer. For example, in a sheet abrasive that contains a polymer layer, an auxiliary layer, and an additional layer, the additional layer can be adjacent to either the polymer layer or the auxiliary layer. The additional layers can have some or all of the characteristics and properties described above for the auxiliary layer and can be made by the same processes and techniques described above. [0066] Sheet abrasives manufactured using abrasive composite materials in accordance with the invention can be used in a variety of ways similar to conventional coated abrasives, such as emery cloth or sand paper. In addition, the sheet abrasives can be thermoformed into a variety of shapes heretofore unobtainable with conventional coated abrasives to create new tools engineered to fit specific applications. Thermoforming involves applying heat and/or pressure to the sheet abrasive to form the sheet into a different three-dimensional shape. For example, in one embodiment according to the invention, a sheet abrasive is thermoformed to fit over the end of a pipe (e.g., similar to the shape of a lid for a disposable drinking cup). The resulting thermoformed sheet abrasive then can be used as a de-burring or polishing tool for the end of like-sized metal pipes.

[0067] In one embodiment, an adhesive polymer layer is disposed between a polymer layer and an auxiliary layer that provides reinforcement, toughening or other attributes. In a variation of this embodiment, the auxiliary layer is a removable backing or liner, which, when removed, exposes the adhesive layer which remains disposed on the polymer layer. The sheet abrasive can then be adhered to another surface using the adhesive layer. In a related embodiment, the auxiliary layer is a fastening system, for example, a hook and loop device (e.g., Velcro®), which can be used to fasten the sheet abrasive to another surface.

[0068] In other embodiments of a sheet abrasive, the polymer layer includes a thermoplastic elastomer, including, but not limited to, soft polyurethanes, polyetheresters, or polyetheramide esters. The sheet abrasive is very flexible and can be used on curved surfaces (e.g., contours of molding, metal rods, etc.) that cannot effectively be sanded by conventional coated abrasives.

[0069] In some embodiments, the auxiliary layer is foamed to provide for shock absorption, insulation, or sound damping qualities. In other embodiments, the auxiliary layer includes fiberglass or clay to provide enhanced stiffness. The auxiliary layer may include a high thermal conductivity filler to enhance cooling of the sheet abrasive. In other embodiments, the auxiliary layer includes tungsten or other high-density fillers to provide a sheet abrasive with increased weight for use in abrasive tools, such as, for example, flap wheels. In yet other embodiments, an intermediate layer is extruded between two thermoplastic polymer layers containing a plurality of abrasive particles to produce an abrasive sheet construction with abrasive on the top and bottom with a reinforcing or toughening layer in between. It is to be understood that, in addition to the embodiments described above, a sheet abrasive in accordance with the present invention can have any configuration of thermoplastic polymer layer, auxiliary layer, and/or additional layers.

[0070] A variety of abrasive tools can be manufactured from the abrasive composite material of the invention. For example, sheet abrasives manufactured using composite materials in accordance with the invention can be cut to any desired length or shape and used directly, like conventional sand paper, or they can be formed into implements or tools. In a particular implement, a sheet abrasive can be cut and the ends joined using conventional bonding or joining techniques to form belts. Alternatively, a sheet abrasive can be cut into flaps and formed into star pads, cross pads, square pads, flap wheels, flap discs, cartridge rolls, spiral bands, overlap discs, overlap cones, and other implements known in the art. Examples of implements that can be formed using sheet abrasives manufactured using abrasive composite materials in accordance with the invention can be found in the catalogue, entitled "3M Grindline Express Coated Abrasive, Surface Conditioning, and Superabrasive Products 1996" (3M Company, Minneapolis, Minnesota). Also, various abrasive implements, including those mentioned above, can be manufactured from abrasive composite materials of the invention by extrusion, molding or other conventional methods without an intermediate step of producing sheet abrasives. [0071] Referring to FIG. 5A, in one embodiment, an abrasive element 100 manufactured from the composite material of invention includes a base 102 from which one or more flaps 104 extend outward. The flaps 104 are integrally formed with the base 102. Although the abrasive element 100 depicted in FIG. 5A includes four flaps 104, abrasive elements of the invention can include any number of flaps (e.g., one, two, three, four, five, six, seven, or eight flaps). The flaps 104 extend outward from the base 102. The flaps 104 can be substantially perpendicular to the base 102, or the flaps 104 can be non-perpendicular. For example, the flaps 104 may extend from the base 102 at an angle, or the flaps 104 may be curved. The flaps 104 can be substantially parallel to one another, as shown in FIG. 5A, or one or more flaps 104 can be non-parallel, as shown in FIG. 5B.

[0072] The cross-sectional width of each flap 104 can be substantially uniform throughout the length of the flap 104, yielding a flap 104 with a substantially rectangular cross-sectional shape, as shown in FIGS. 5A-5B. In other embodiments, the abrasive element 200 includes a flap 202 that is wider at its first end 204 nearest the base 206 than at its second end 208 away from the base 206, and the flap 202 tapers down from the first end 204 to the second end 208, as shown in FIG. 6. Also, the configuration depicted in FIG. 6 can be inverted, yielding a flap that is wider at the end furthest away from the base. The cross- sectional shape of the flaps can be tailored to have any cross-sectional shape that suits the particular application to which the abrasive element will be applied. In multi-flap abrasive elements, each flap may have substantially the same shape and/or dimensions, or one or more flaps may have different shapes and/or dimensions. [0073] Referring to FIGS. 7A and 7B, in some embodiments, the base 302 of the abrasive element 300 has a larger cross-sectional width W_b than the cross-sectional width W_f of the flap 304. The base 302 depicted in FIG. 7A has a rectangular cross-sectional shape; however, the base may have any cross-sectional shape, including, but not limited to, circular (as shown in FIG. 7B), semicircular, oval, square, and quadrilateral.

[0074] In other embodiments, the base has substantially the same cross- sectional width as the flap. Referring FIG. 8, in some embodiments, an abrasive element 400 includes a base 402 connected to a flap 404 by a connecting section 406. The base 402 has substantially the same cross-sectional width W_b as the cross-sectional width W_f of the flap 404, while the cross-sectional width of the connecting section 406 is smaller than Wf and wt,.

[0075] Referring to FIG. 9, in yet another embodiment, an abrasive element 500 includes a flap 502 that has a first end 504 and a second end 506. The first end 504 has a larger cross-sectional width Wi than the cross-sectional width w₂ of the second end 506, and the flap 502 tapers down from the first end 504 to the second end 506. In this embodiment, the first end 504 functions as the base that is present in the embodiments described above.

[0076] Referring to FIG. 10A, in still another embodiment, in an abrasive element 600, length L_f of a flap 602 may be substantially equal to length U of a base 604. In these embodiments, a front edge 606 and a back edge 608 of the flap 602 are aligned and substantially continuous with a front edge 610 and a back edge 612 of the base 604, respectively. In other embodiments, the length L of the flap 604 may be less than the length U of the base 604, as shown in FIG. 10B. In the abrasive element 600 depicted in FIG. 10B, neither the front edge 606 nor the back edge 608 of the flap 602 is aligned and substantially continuous with the front edge 610 and the back edge 612 of the base 604, respectively. In other embodiments, only one of the front edge 606 and the back edge 608 of the flap 602 is aligned and substantially continuous with the front edge 610 or the back edge 612 of the base 604, respectively, while the other edges are not aligned. [0077] As mentioned above, in various embodiments of the invention, the flaps and/or the base are fabricated from a polymer material having a plurality of abrasive particles embedded therein. The abrasive particles can be dispersed substantially uniformly throughout the abrasive element, or they can be dispersed in a non-uniform fashion. For example, the concentration of abrasive elements may be greater in the flaps than in the base. In certain embodiments, the polymer material comprises one or more polyarylene sulfides, for example, a polyphenylene sulfide.

[0078] In the illustrative embodiments shown in FIG. 11 A and 11 B, an abrasive element 700 includes a reinforcing member 702 adjacent to or embedded within the base 704. The reinforcing member 702 can serve to enhance various properties of the base, including, for example, stiffness, toughness, resilience, and/or thermal coefficient of expansion. The reinforcing member 702 can be made of any material, including, for example, paper, cloth, metal, polymer, or combinations thereof. The reinforcing member 702 can have various forms (e.g., a continuous sheet, a wire or fiber, a fibrous woven or non-woven belt, or a web or mesh) provided the reinforcing member 702 is shape-compatible with the base 704. Suitable metals for use in a reinforcing member 702, for example, aluminum, chromium, steel, and alloys thereof. Any of the thermoplastic polymers or combination of polymers described above can be used to form the reinforcing member 702. In addition, the reinforcing member 702 can include any of the abrasive particles and/or additives described above.

[0079] In embodiments where the reinforcing member 702 is disposed adjacent to the base 704, the reinforcing member 702 can be bonded to the base 704 using an adhesive, or the reinforcing member 702 can be coated or sprayed onto to the base 704. In cases where the reinforcing member 702 includes a polymer, the reinforcing member 702 can be extruded onto the base 704, or the reinforcing member 702 can be co-extruded with the abrasive element 700. A co-extrusion process involves extruding two or more layers simultaneously by combining the extrudates from multiple extruders into a manifold and extruding through a special multi-layer die. Alternatively, the reinforcing member 702 can be present within a mold prior to injecting a molten thermoplastic layer into the mold. Each layer can have the same or different widths, and the layers may be offset.

[0080] Abrasive elements of the invention can be incorporated into abrasive tools for sanding, polishing, and/or cleaning various surfaces and materials. FIGS. 12A and 12B depict an illustrative embodiment of an abrasive tool 800 that includes a support 802 and a plurality of abrasive elements 804 of the invention. Although the abrasive tool 800 depicted in FIGS. 12A and 12B contains eight abrasive elements 804, any number of abrasive elements may be incorporated into an abrasive tool of the invention, including abrasive tools that contain a single abrasive element. Any embodiment of an abrasive element described herein may be incorporated into an abrasive tool of the invention. For example, the illustrative embodiment of FIGS. 12A and 12B show an abrasive element 804 that contain four flaps 806, while FIGS. 13 shows an alternative embodiment of an abrasive tool 900, wherein the abrasive elements 902 each contain a single flap 904 extending outward from a support 906.

[0081] Referring again to FIGS. 12A and 12B, the support 802 is planar and circular. Other shapes of planar supports may also be incorporated into abrasive tools of the invention, including, for example, oval, rectangular, square, and irregular shapes. The shape of the planar support can be tailored to suit the application to which the abrasive tool will be applied. The support may also be non-planar, such as, for example, a cylindrical support 1002 depicted in FIG.14.

[0082] Abrasive elements may be attached to the support by any method known in the art. Examples include nailing or screwing, affixing with an adhesive, clamping, or using a hook-and-loop fastener (e.g., Velcro®). Preferably, the abrasive elements are reversibly attached to the support. Referring again to. FIGS. 12A and 12B, in some embodiments, the support 802 contains connecting structures 808 adapted for receiving the bases 810 of the abrasive elements 804. The connecting structures 808 are slots or grooves in the surface of the support 802 that correspond to the shape of the base 810. FIG. 15A depicts another embodiment of a connecting structure 1100 that includes two raised ridges 1102 that are connected to a support 1104. The raised ridges 1102 may have any shape, such as, for example, the inverted L-shaped raised ridges 1102 depicted in FIG. 15B, provided the raised ridges 1102 are complimentary to the shape of the abrasive element's base. In order to attach an abrasive element 804 to the support 802, the base 810 of the abrasive element 804 is inserted into the connecting structure 808. In some embodiments, a retaining structure is used to maintain contact between the base 810 of the abrasive element 804 and the connecting structure 808. For example, a retaining ring 812 may be positioned around the outer rim 814 of the support 802 to prevent the abrasive elements 804 from sliding back out of the connecting structures 808. Any type of retaining structure known in the art may be used in abrasive tools of the invention, including, for example, clamps and screws. After use, the retaining structure may be disengaged and the abrasive elements removed from the support. [0083] In various embodiments, the supports 802, 906, and 1002 are adapted for rotation. For example, referring to FIGS. 12A and 12B, the connecting members 808 are arranged radially around the axis labeled A-A so that when the abrasive tool 800 is rotated about the A-A axis, the flaps 806 abrasive elements 804 are aligned perpendicularly to the direction of rotation. In other embodiments, the support may be adapted for other motions, such as lateral or irregular motions. In these embodiments, the connecting members and abrasive elements need not be arranged radially about an axis; the connecting members and abrasive elements may be arranged in any order or pattern compatible with the motion of the support (e.g., with the flaps aligned perpendicular to the motion of the support).

[0084] The following examples are provided for illustration purposes only and are not intended to limit the invention in any way.

[0085] The experimental samples of thermoplastic sheet abrasives (TSA) tested as described below were prepared on a 70 mm single screw extruder with a downstream solids addition port. The extruder barrel temperatures were set to about 260° C for nylon and to about 280° C for polyphenylene sulfide. A 6-inch wide sheet die on a conventional coat hanger sheet manifold (with an internal sheet thickness adjustment bar) was used for extruding samples containing abrasive grains as coarse as 36 mesh. The particular 6-inch sheet manifold and die used for this work had channels too narrow to pass abrasive grains coarser than 36 mesh. Therefore a simple slot die, with adequate clearance, was used for the 20 mesh abrasive extrusion experimental samples (without a sheet manifold). The sheet extrudate exited vertically downward into a heated water bath and threaded around a few rods and was brought back up out of the water, through a set of vacuum strippers and then through a set of speed controlled rolls. The material was then cut into sections after exiting the rolls for collection and testing.

[0086] The nylons used for the comparative examples were Zytel® Fe3071 (supplied by the DuPont Company, www.dupont.com) and Nilit N-100 (purchased from Nilit, www.nilit.com). The PPS was Fortran® 0320 extrusion grade (supplied by Ticona, www.ticona.com). The aluminum oxide abrasive grains were obtained from the AGSCO Corporation. The polydimethyl siloxane was a 350 centistoke grade purchased from Path Silicones (no longer doing business) but equivalent grades can readily be obtained from Dow Corning Silicones. The 350 centistoke polydimethylsiloxane was used because it was on hand, it is not an especially preferred viscosity grade for this application. Generally, higher molecular weight siloxanes are expected to work better provided they can be conveniently incorporated into the compound. The 3M Company's Scotch-Brite™ Roloc™ Surface Conditioning Disc TR 3 inch and 2 inch A CRS (coarse) were purchased from W.W. Grainger, Inc. (Grainger, 20 Gregory Drive, South Burlington, VT). [0087] The percent abrasive for the nylon TSA was determined by ashing the nylon in a furnace (% abrasive= 100 X (ash weight/sample weight). The percent abrasive for the polyphenylene sulfide was determined by measuring feed rates to the extruder because the polyphenylene sulfide TSA will not burn.

[0088] The nylon and polyphenylene TSA discs were cut from the extruded sheet and Roloc™ style threaded connectors were glued to the center of the discs with a two-part epoxy glue for testing. The epoxy used was purchased from Fielco Industries of Huntingdon Valley, Pa. The epoxy grades were MW 5977 A-50 and MW977B.

[0089] The testing device was custom made and consists of an electric motor driven spindle that controls speed to 21 ,000 rpm without substantial speed variation for loads up to 10 lbs against the spindle. The abrasive discs with attached, threaded Roloc™ style fasteners were screwed onto a two or three inch rubber backing pad equipped with a shaft to mount to the spindle. The work-piece (stainless steel) is mounted on an air-pressurized slide that slides forward when pressurized with air to bring the work-piece into contact with the test abrasive mounted on the spindle. The air pressure controls the force of the work piece against the spinning tool. The force is measured before the test directly with a 20 lb Berkley electronic fish scale. The 1 inch wide by 6 inch long (by 0.25 inch thick) rectangular work piece is attached to the sliding mechanism by screws. In addition to sliding the workpiece forward to contact the tool, the slide also cycles horizontally back and forth (in a perpendicular direction to the axis of the slide). For the disc testing discussed in this work the work-piece (slide) is positioned at a 30° angle to the disc plane of the spinning tool. The work-piece moves over a 4.25 inch path (in the same direction as the major axis of the work-piece) in 3 seconds and then returns to its' initial position over the next 3 seconds. It repeats this back and forth motion continuously for the duration of the test at which time the air pressure is released and the work piece is drawn back from the tool and the test is ended.

[0090] The work piece weight is measured before and after the test to measure the amount of metal removed. In a similar manner, the tool is weighed before and after the test to determine how much the tool has been degraded. The cut rate is a measure of how many grams of metal were removed per minute of test cycle. The grind ratio is a measure of the weight of metal removed divided by the weight of tool lost. Cut rate is a measure of how fast the tool works while the grind ratio can be interpreted as a measure of how long the tool will last. Smear is a term used to describe any visible residue left on the work piece from the tool. Smear is undesirable and was qualitatively, visually judged relative to smear from the 3M Company's Scotch-Brite™ Roloc™ Surface Conditioning Disc TR. Surface finish was measured with a Mitutoyo SurfTest 301. [0091] Table 1 lists abrasive sample compositions. TSA-N-1 and TSA-N-2 are nylon abrasive comparison samples. TSA-PPS-3 and TSA-PPS-4 are polyphenylene sulfide abrasive compositions of the current invention. Table 2 lists the sample extrusion conditions. TABLE 1

TABLE 2

[0092] Table 3 shows a comparison of cut rates of two-inch diameter discs made from TSA-N-1 and TSA-PPS-3 with Scotch-Brite™ A CRS (coarse). The polyarylene sulfide disc, TSA-PPS-3, surprisingly has an average cut rate 3.5 times higher than nylon disc, TSA-N-1 , even though both have the same 20 mesh coarse abrasive grain. The polyarylene sulfide TSA, TSA-PPS-3, also has an average cut rate 1.2 times higher than the state of the art commercial abrasive, Scotch-Brite™ A CRS. The TSA-PPS-3 material also has superior grind ratio to either the nylon TSA-N-1 or the Scotch-Brite™ A CRS.

TABLE 3

[0093] Table 4 lists experimental results comparing a 3-inch disc of nylon containing 36 mesh aluminum oxide abrasive, TSA-N2, with a 3-inch disc of Scotch- Brite™ A CRS. The 3 inch nylon TSA disc has far inferior cut compared with the 3- inch Scotch-Brite™ A CRS. This result is similar to the results obtained with the 2- inch nylon discs. The nylon TSA has inferior cut rate to the state of the art Scotch- Brite™ A CRS product. TABLE 4

[0094] Table 5 lists the results of an experiment comparing cutting rates of the polyarylene sulfide 3-inch abrasive disc containing 36 mesh aluminum oxide abrasive grain, TSA-PPS-4, with 3-inch Scotch-Brite™ A CRS, both on a 3 inch back pad. These results are graphically depicted in FIG. 16. As shown in FIG. 16, the cut rates and durability of the abrasive disk manufactured from TSA-PPS-4 abrasive composite material exceed those of the Scotch-Brite™ A CRS product. The final surface finish for the TSA-PPS-4 was the same as the Scotch-Brite™ A CRS as indicated by the same final Ra number for each of 15 μin. [0095] Still referring to FIG. 16, unlike the Scotch-Brite™ A CRS product, TSA- PPS-4 abrasive disk continues to cut effectively beyond the initial 3 four-minute cycles, whereas after 12 minutes of operation, the Scotch-Brite™ A CRS pad showed surface smear on the metal because the abrasive contact layer had worn away. The Scotch-Brite™ A CRS disc cannot be conveniently dressed due to its physical non-woven structure. Dressing is a term used to define a process by which the worn out outside of the disk is rapidly abraded away in several seconds by running it on edge (disc plane perpendicular to the plane of the sandpaper or other sharp cutting surface) to give a fresh outside surface for continued work. Dressing reduces the disc diameter a small amount. The TSA-PPS-4 abrasive disk could be rapidly and conveniently dressed, when its cut rate substantially decreased. Each time the disc was dressed, its cut rate increased dramatically over the last cycle. So, TSA-PPS-4 disk was dressed each time the total cut for a four-minute cycle reached about 0.5 grams of stainless steel. The disc could then be used to do more and more work. After the first dressing, a 2-inch back pad was used for the remainder of the test. Each time the disc diameter was reduced by 0.25 inches due to dressing, the test speed was increased proportionately in an effort to keep the same disc surface speed, until a speed of 21 ,400 rpm was reached, which was the maximum operating speed for the tester. The test was ended when the TSA disc reached about 2 inches overall diameter.

TABLE 5

[0096] The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

CLAIMS1. An abrasive composite material comprising: a polymer layer comprising one or more polyarylene sulfides; and a plurality of abrasive particles at least partially embedded therein.

2. The abrasive composite material of claim 1 , wherein at least one of the polyarylene sulfides comprises polyphenylene sulfide.

3. The abrasive composite material of claim 1 , wherein the plurality of abrasive particles is selected from the group consisting of silicon carbide, aluminum oxide, diamond, ceramic aluminum oxide, ceramic, zirconia aluminum, garnet, cubic boron nitride, and talc.

4. The abrasive composite material of claim 1 , wherein the plurality of abrasive particles is dispersed substantially uniformly throughout the polymer layer.

5. The abrasive composite material of claim 1 , wherein the abrasive particles comprise from about 1% to about 40% by volume of the polymer layer.

6. The abrasive composite material of claim 1 , wherein the polymer layer comprises a foamed polymer.

7. An abrasive element comprising the abrasive composite material of claim 1 , the abrasive element is selected from the group consisting of: a disc, a flap wheel, and a continuous belt.

8. A sheet abrasive comprising the abrasive composite material of claim 1 , the sheet abrasive having thickness ranging from about 0.01 inch to about 0.125 inch.

9. The abrasive composite material of claim 1 , further comprising an auxiliary layer adjacent to the polymer layer.

10. The abrasive composite material of claim 9, wherein the auxiliary layer comprises at least one polyarylene sulfide.

11. The abrasive composite material of claim 10, wherein the auxiliary layer further comprises a plurality of abrasive particles at least partially embedded therein.

12. The abrasive composite material of claim 9, further comprising an adhesive layer disposed between the polymer layer and the auxiliary layer.

13. A method of forming an abrasive composite material comprising the steps of: (a) providing a volume of molten polymer material comprising one or more polyarylene sulfides, (b) dispersing a plurality of abrasive particles in the molten polymer material; and (c) causing the polymer material having the plurality of abrasive particles at least partially embedded therein to assume a predetermined shape.

14. The method of claim 13, wherein the step (c) comprises extruding the polymer material.

15. The method of claim 14, wherein polymer material is extruded to form a sheet abrasive having thickness ranging from about 0.01 inch to about 0.125 inch.

16. The method of claim 14, further comprising, after step (c), orienting the extruded polymer material in a uni-axial or bi-axial direction thereby a polymer layer.

17. The method of claim 16, wherein the step of orienting the extruded polymer material comprises stretching thereof.

18. The method of claim 16, further comprising providing an auxiliary layer adjacent to the polymer layer.

19. The method of claim 18, wherein the auxiliary layer comprises a plurality of abrasive particles.

20. The method of claim 18, wherein the auxiliary layer comprises at least one polyarylene sulfide.

21. The method of claim 18, wherein the step of providing the auxiliary layer comprises co-extruding the polymer layer and the auxiliary layer.

22. The method of claim 20, wherein the step of providing the second layer comprises adhering the auxiliary layer to the extruded polymer layer.

23. The method of claim 13, wherein the step (c) comprises molding.

24. An abrasive element comprising: a base; and at least one flap integrally formed with and extending from the base, the base and the at least one flap comprising an abrasive composite material, the abrasive composite material comprising a plurality of abrasive particles at least partially embedded within a polymer layer comprising one or more polyarylene sulfides.

25. The abrasive element of claim 24, wherein at least one of the polyarylene sulfides comprises polyphenylene sulfide.

26. The abrasive element of claim 24, wherein the base has a larger cross- sectional width than the flap.

27. The abrasive element of claim 24, wherein the flap comprises a first end adjacent to the base and a second end distal to the base, the first end of the flap having a larger cross-sectional width than the second end of the flap.

' 28. The abrasive element of claim 27, wherein the flap tapers from the first end to the second end.

29. An abrasive element comprising: a flap having a first end and a second end, wherein the first end of the flap has a larger cross-sectional width than the second end of the flap, and the flap comprising an abrasive composite material, the abrasive composite material comprising a plurality of abrasive particles at least partially embedded within a polymer layer comprising at least one polyarylene sulfide.

30. The abrasive element of claim 29, wherein the polyarylene sulfide comprises polyphenylene sulfide.

31. An abrasive tool comprising at least one abrasive element of claim 24 and a support comprising one or more connecting structures for associating the base of the abrasive element with the support, wherein the at least one flap of the abrasive element extend away from a surface of the support.

32. The abrasive tool of claim 31 , wherein the support comprises a planar structure.

33. The abrasive tool of claim 32, wherein the planar support is circular.

34. The abrasive tool of claim 31 , wherein the support comprises a cylinder.

35. The abrasive tool of claim 31 , wherein the support is rotatable.

36. The abrasive tool of claim 31 , wherein the at least one connecting structure defines one or more grooves in the support.

37. The abrasive tool of claim 31 , wherein the connecting structure comprises one or more raised ridges disposed on a surface of the support.

38. The abrasive tool of claim 31 , further comprising a retaining structure for maintaining contact between the connecting member and the abrasive element.

39. The abrasive tool of claim 38, wherein the retaining structure comprises a retaining ring.