Patent Application
20240091908
Abrasive particles and abrasive articles made from the abrasive particles are useful for abrading, finishing, or grinding a wide variety of materials and surfaces in the manufacturing of goods. As such, there continues to be a need for improving the cost, performance, or life of abrasive particles or abrasive articles.
The present disclosure provides an abrasive article. The abrasive article includes a spunbond web. The spunbond web includes a first major surface and an opposite second major surface and a fiber component. The article further includes a binder dispensed on the fiber component. The article further includes abrasive particles substantially retained by the binder and dispersed about the first major surface of the nonwoven web and substantially forming a predetermined pattern.
The present disclosure provides a method for forming an abrasive article. The abrasive article includes a spunbond web. The spunbond web includes a first major surface and an opposite second major surface and a fiber component. The article further includes a binder dispensed on the fiber component. The article further includes abrasive particles substantially retained by the binder and dispersed about the first major surface of the nonwoven web and substantially forming a predetermined pattern. The method includes positioning the first major surface or the second major surface of the spunbond web substantially in-line with a perforated screen. The method further includes dispersing the binder through individual perforations of the perforated screen to form a plurality of binder pockets arranged in a predetermined pattern on the first major surface of the second major surface. The method further includes contacting the plurality of binder pockets with the abrasive particles. An initial viscosity of the binder prior to and during dispersing is less than a final viscosity of the binder upon contact with the first major surface or the second surface.
The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.
Reference will now be made in detail to certain embodiments of the disclosed subject matter, examples of which are illustrated in part in the accompanying drawings. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.
Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.
In this document, the terms “a”, “an”, or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.
In the methods described herein, the acts can be carried out in any order without departing from the principles of the disclosure, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.
The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.
The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%.
As used herein “shaped abrasive particle” means an abrasive particle having a predetermined or non-random shape. One process to make a shaped abrasive particle such as a shaped ceramic abrasive particle includes shaping the precursor ceramic abrasive particle in a mold having a predetermined shape to make ceramic shaped abrasive particles. Ceramic shaped abrasive particles, formed in a mold, are one species in the genus of shaped ceramic abrasive particles. Other processes to make other species of shaped ceramic abrasive particles include extruding the precursor ceramic abrasive particle through an orifice having a predetermined shape, printing the precursor ceramic abrasive particle through an opening in a printing screen having a predetermined shape, or embossing the precursor ceramic abrasive particle into a predetermined shape or pattern. In other examples, the shaped ceramic abrasive particles can be cut from a sheet into individual particles. Examples of suitable cutting methods include mechanical cutting, laser cutting, or water-jet cutting. Non-limiting examples of shaped ceramic abrasive particles include shaped abrasive particles, such as triangular plates, or elongated ceramic rods/filaments. Shaped ceramic abrasive particles are generally homogenous or substantially uniform and maintain their sintered shape without the use of a binder such as an organic or inorganic binder that bonds smaller abrasive particles into an agglomerated structure and excludes abrasive particles obtained by a crushing or comminution process that produces abrasive particles of random size and shape. In many embodiments, the shaped ceramic abrasive particles comprise a homogeneous structure of sintered alpha alumina or consist essentially of sintered alpha alumina.
Backing 102 can include a spunbond or nonwoven fiber web that includes a fiber component, such that abrasive article 100 is a nonwoven abrasive article. The fiber component ranges from about 5 wt % to about 95 wt % of abrasive article 100, about 50 wt % to about 95 wt %, less than, equal to, or greater than about 5 wt %, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or about 95 wt %. Backing 102 can be compressed or non-compressed. The fiber component can include continuous fibers, staple fibers, or a combination thereof. For example, the fiber web may comprise staple fibers having a length of at least about 20 millimeters (mm), at least about 30 mm, or at least about 40 mm, and less than about 110 mm, less than about 85 mm, or less than about 65 mm, although shorter and longer fibers (e.g., continuous filaments) may also be useful. The fibers may have a fineness or linear density of at least about 1.7 decitex (dtex, i.e., grams/1000 meters), at least about 6 dtex, or at least about 17 dtex, and less than about 560 dtex, less than about 280 dtex, or less than about 120 dtex, although fibers having lesser and/or greater linear densities may also be useful. Mixtures of fibers with differing linear densities may be useful, for example, to provide an abrasive article that upon use will result in a specifically preferred surface finish.
The fiber web can be reinforced, for example, using a saturant or prebond resin (e.g., a phenolic, urethane, styrene butadiene or acrylic resin), by including core-sheath melty fibers, and/or by mechanical entanglement (e.g., hydroentanglement, or needletacking) using methods well-known in the art. The fiber web can optionally incorporate or be secured to a scrim and/or backing (e.g., using glue or a hot-melt adhesive or by needletacking), if desired, for additional reinforcement. Nonwoven fiber webs can be selected to be suitably compatible with adhering binders and abrasive particles while also being processable in combination with other components of the article, and typically can withstand processing conditions (e.g., temperatures) such as those employed during application and curing of the curable composition. The fibers may be chosen to affect properties of the abrasive article such as, for example, flexibility, elasticity, durability or longevity, abrasiveness, and finishing properties. Examples of fibers that may be suitable include natural fibers, synthetic fibers, and mixtures of natural and/or synthetic fibers. Examples of synthetic fibers include those made from polyester (e.g., polyethylene terephthalate), nylon (e.g., hexamethylene adipamide, or polycaprolactam), polypropylene, acrylonitrile (i.e., acrylic), rayon, cellulose acetate, polyvinylidene chloride-vinyl chloride copolymers, and vinyl chloride-acrylonitrile copolymers. Examples of suitable natural fibers include cotton, wool, jute, and hemp. The fiber may be of virgin material or of recycled or waste material, for example, reclaimed from garment cuttings, carpet manufacturing, fiber manufacturing, or textile processing. The fiber may be homogenous or a composite such as a bicomponent fiber (e.g., a co-spun sheath-core fiber). The fibers may be tensilized and crimped. Combinations of fibers may also be used. Although the nonwoven fiber web is shown as a single layer, it is possible for the web to include multiple layers. Each layer can have the same composition or a different composition.
Prior to coating with binder 104, the nonwoven fiber web can have a weight per unit area (e.g., basis weight) of at least about 50 grams per square meter (gsm), at least about 100 gsm, or at least about 200 gsm; and/or less than about 500 gsm, less than about 450 gsm, or less than about 400 gsm, as measured prior to any coating (e.g., with the curable composition or optional pre-bond resin) in a range of from about 50 gsm to about 500 gsm, 80 gsm to about 120 gsm, less than, equal to, or greater than about, 50 gsm, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, or about 500 gsm, although greater and lesser basis weights may also be used. In addition, prior to impregnation with the curable composition, the fiber web typically has a thickness of at least about 0.05 millimeters (mm), 1 mm, at least about 0.1 mm, at least about 0.5 mm, at least about 1 mm at least about 2 mm, or at least about 3 mm; and/or less than about 100 mm, less than about 50 mm, or less than about 25 mm, although greater and lesser thicknesses may also be useful, or in a range of from about 0.05 mm to about 100 mm, about 0.1 to about 0.5 mm. A machine direction tensile strength of the nonwoven fiber web can be in a range of from about 300 N/5 cm to about 1000 N/5 cm, about 400 N/5 cm to about 700 N/5 cm, or less than, equal to, or greater than about 300 N/5 cm, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or about 1000 N/5 cm. A cross direction tensile strength of the nonwoven fiber web can be in a range of from about 200 N/5 cm to about 1000 N/5 cm, about 400 N/5 cm to about 700 N/5 cm, or less than, equal to, or greater than about 200 N/5 cm, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, or about 1000 N/5 cm. The machine direction elongation at break can be in a range of from about 1% to about 13%, 5% to about 10%, less than greater than, or equal to about 1%, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, or about 13%. The cross direction elongation at break can be in a range of from about 1% to about 13%, 5% to about 10%, less than greater than, or equal to about 1%, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, or about 13%.
It can be useful to apply a saturant to the nonwoven fiber web prior to coating with binder 104. The saturant serves, for example, to help maintain the nonwoven fiber web integrity during handling, and may also facilitate bonding of the binder resin to the nonwoven fiber web. Moreover, the saturant can help to seal off pores in the individual fibers that can affect the visual perception of abrasive article 100. Also the presence of pores can result in an unstable platform to attach abrasive particles 300 or 400 to. If the pores are substantially sealed, abrasive particles 300 or 400 can have a level or otherwise clean surface of backing 102 to contact. Following application of the saturant, a porosity of the fibers can be in a range of from about 10% to about 70%, about 20% to about 50%, less than, equal to, or greater than about 10%, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70%.
Examples of suitable saturants include phenolic resins, urethane resins, styrene butadiene, hot glue, acrylic resins, urea-formaldehyde resins, melamine-formaldehyde resins, epoxy resins, and combinations thereof. In some embodiments, the saturant can further include a urea formaldehyde resin and a compatible latex. The latex can include an acrylic emulsion. The amount of saturant used in this manner is typically adjusted toward the minimum amount consistent with bonding the fibers together at their points of crossing contact. In those cases, wherein the nonwoven fiber web includes thermally bondable fibers, thermal bonding of the nonwoven fiber web may also be helpful to maintain web integrity during processing. Various other optional conventional treatments and additives may be used in conjunction with the nonwoven fiber web such as, for example, application of antistatic agents, lubricants, or corona treatment.
Binder 104 secures shaped abrasive particles 300 or 400 to backing 102, and size coat 106 can help to reinforce shaped abrasive particles 300 or 400. Binder 104 can range from about 10 wt % to about 70 wt % of abrasive article 100, about 30 wt % to about 50 wt %, less than, equal to, or greater than about 10 wt %, 20, 30, 40, 50, 60, or 70 wt %.
Binder 104 and/or size coat 106 can include a resinous adhesive. The resinous adhesive can include one or more resins chosen from phenolic resins, melamine resins, aminoplast resins having pendant α-, β-unsaturated carbonyl groups, urethane resins, epoxy resins, ethylenically unsaturated resins, acrylated isocyanurate resins, urea-aldehyde resins, isocyanurate resins, acrylated urethane resins, acrylated epoxy resins, bismaleimide resins, fluorene-modified epoxy resins, a urea formaldehyde resin, a phenolic formaldehyde resin, and a melamine formaldehyde resin, and combinations thereof. The rheological properties of binder 104 can be controlled through the addition of various additives. For example, binder 104 can include fumed silica particles. The fumed silica particles can be in a range of from about 1 wt % to about 15 wt % of abrasive article 100, about 2 wt % to about 5 wt %, less than, equal to, or greater than about 1 wt %, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt %. The fumed silica particles can alter the viscosity of binder 104 such that an initial viscosity of binder upon application is low enough that it can pass through a screen but that a final viscosity of the binder 104 after contact with backing 102 is high enough that it remains in place on backing 102. The initial and final viscosity values can independently be in a range of from about 10,000 cps at about 30° C. to about 1,000,000 cps, about 50,000 cps to about 350,000 cps, or less than, equal to, or greater than about 20,000 cps, 50,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000, 450,000, 500,000, 550,000, 600,000, 650,000, 700,000, 750,000, 800,000, 850,000, 900,000, 950,000, or about 1,000,000 cps.
Other additives to binder 104, size coat 106, or both can include a wax or a latex. Examples of suitable latex materials can include a latex having natural rubber, butadiene rubber, styrene-butadiene rubber, styrene-butadieneacrylonitrile rubber, chloroprene rubber and methyl-butadiene rubber, cellulose and acrylic and vinyl acetate emulsions.
Binder 104 is not applied over the entire surface area of either the first or second major surfaces of backing 102. Instead quantities of binder 104 are selectively applied to certain regions of backing 102 to form binder pockets 200 across backing 102 in the x-y direction. Each binder pocket 200 includes binder 104, abrasive particle 300 or 400, and optionally size coat 106. The selective inclusion of binder pockets 200 on backing leaves some portions of backing 102 uncovered. The total surface area of either first or second major surface that is covered by binder pockets 200 can be in a range of from about 10% to about 90% of the total surface are of the first or second major surfaces, about 30% to about 50%, less than, equal to, or greater than about 10%, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or about 90%. Individual binder pockets 200 can include the same or a different composition.
Selectively forming binder pockets 200 allows for abrasive particles 300 or 400 to be deployed on backing 102 in a variety of predetermined three-dimensional patterns. For example,
The abrasive properties of abrasive article 100 can further be a function of the type of abrasive particle 300 or 400 located therein. For example, binding pockets 200 can include what are referred to as shaped abrasive particles. As an example,
In the embodiment shown in
As another example,
Referring now to
Referring now to
Referring now to
Deviations from the depictions in
In any of shaped abrasive particles 400A-400E, the edges can have the same length or different lengths. The length of any of the edges can be any suitable length. As an example, the length of the edges can be in a range of from about 0.5 μm to about 2000 μm, about 150 μm to about 200 μm, or less than, equal to, or greater than about 0.5 μm, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, or about 2000 μm. shaped abrasive particles 400A-400E can be the same size or different sizes.
Any of shaped abrasive particles 300 or 400 can include any number of shape features. The shape features can help to improve the cutting performance of any of shaped abrasive particles 300 or 400. Examples of suitable shape features include an opening, a concave surface, a convex surface, a groove, a ridge, a fractured surface, a low roundness factor, or a perimeter comprising one or more corner points having a sharp tip. Individual shaped abrasive particles can include any one or more of these features.
Shaped abrasive particle 300 or 400 can be formed in many suitable manners for example, the shaped abrasive particle 300 or 400 can be made according to a multi-operation process. The process can be carried out using any material or precursor dispersion material. Briefly, for embodiments where shaped abrasive particles 300 or 400 are monolithic ceramic particles, the process can include the operations of making either a seeded or non-seeded precursor dispersion that can be converted into a corresponding (e.g., a boehmite sol-gel that can be converted to alpha alumina); filling one or more mold cavities having the desired outer shape of shaped abrasive particle 300 or 400 with a precursor dispersion; drying the precursor dispersion to form precursor shaped abrasive particle; removing the precursor shaped abrasive particle from the mold cavities; calcining the precursor shaped abrasive particle to form calcined, precursor shaped abrasive particle 300 or 400; and then sintering the calcined, precursor shaped abrasive particle 300 or 400 to form shaped abrasive particle 300 or 400. The process will now be described in greater detail in the context of alpha-alumina-containing shaped abrasive particle 300 or 400. In other embodiments, the mold cavities may be filled with a melamine to form melamine shaped abrasive particles.
The process can include the operation of providing either a seeded or non-seeded dispersion of a precursor that can be converted into ceramic. In examples where the precursor is seeded, the precursor can be seeded with an oxide of an iron (e.g., FeO). The precursor dispersion can include a liquid that is a volatile component. In one example, the volatile component is water. The dispersion can include a sufficient amount of liquid for the viscosity of the dispersion to be sufficiently low to allow filling mold cavities and replicating the mold surfaces, but not so much liquid as to cause subsequent removal of the liquid from the mold cavity to be prohibitively expensive. In one example, the precursor dispersion includes from 2 percent to 90 percent by weight of the particles that can be converted into ceramic, such as particles of aluminum oxide monohydrate (boehmite), and at least 10 percent by weight, or from 50 percent to 70 percent, or 50 percent to 60 percent, by weight, of the volatile component such as water. Conversely, the precursor dispersion in some embodiments contains from 30 percent to 50 percent, or 40 percent to 50 percent solids by weight.
Examples of suitable precursor dispersions include zirconium oxide sols, vanadium oxide sols, cerium oxide sols, aluminum oxide sols, and combinations thereof. Suitable aluminum oxide dispersions include, for example, boehmite dispersions and other aluminum oxide hydrates dispersions. Boehmite can be prepared by known techniques or can be obtained commercially. Examples of commercially available boehmite include products having the trade designations “DISPERAL” and “DISPAL”, both available from Sasol North America, Inc., or “HIQ-40” available from BASF Corporation. These aluminum oxide monohydrates are relatively pure; that is, they include relatively little, if any, hydrate phases other than monohydrates, and have a high surface area.
The physical properties of the resulting shaped abrasive particle 300 or 400 can generally depend upon the type of material used in the precursor dispersion. As used herein, a “gel” is a three-dimensional network of solids dispersed in a liquid.
The precursor dispersion can contain a modifying additive or precursor of a modifying additive. The modifying additive can function to enhance some desirable property of the abrasive particles or increase the effectiveness of the subsequent sintering step. Modifying additives or precursors of modifying additives can be in the form of soluble salts, such as water-soluble salts. They can include a metal-containing compound and can be a precursor of an oxide of magnesium, zinc, iron, silicon, cobalt, nickel, zirconium, hafnium, chromium, yttrium, praseodymium, samarium, ytterbium, neodymium, lanthanum, gadolinium, cerium, dysprosium, erbium, titanium, and mixtures thereof. The particular concentrations of these additives that can be present in the precursor dispersion can be varied.
The introduction of a modifying additive or precursor of a modifying additive can cause the precursor dispersion to gel. The precursor dispersion can also be induced to gel by application of heat over a period of time to reduce the liquid content in the dispersion through evaporation. The precursor dispersion can also contain a nucleating agent. Nucleating agents suitable for this disclosure can include fine particles of alpha alumina, alpha ferric oxide or its precursor, titanium oxides and titanates, chrome oxides, or any other material that will nucleate the transformation. The amount of nucleating agent, if used, should be sufficient to effect the transformation of alpha alumina.
A peptizing agent can be added to the precursor dispersion to produce a more stable hydrosol or colloidal precursor dispersion. Suitable peptizing agents are monoprotic acids or acid compounds such as acetic acid, hydrochloric acid, formic acid, and nitric acid. Multiprotic acids can also be used, but they can rapidly gel the precursor dispersion, making it difficult to handle or to introduce additional components. Some commercial sources of boehmite contain an acid titer (such as absorbed formic or nitric acid) that will assist in forming a stable precursor dispersion.
The precursor dispersion can be formed by any suitable means; for example, in the case of a sol-gel alumina precursor, it can be formed by simply mixing aluminum oxide monohydrate with water containing a peptizing agent or by forming an aluminum oxide monohydrate slurry to which the peptizing agent is added.
Defoamers or other suitable chemicals can be added to reduce the tendency to form bubbles or entrain air while mixing. Additional chemicals such as wetting agents, alcohols, or coupling agents can be added if desired.
A further operation can include providing a mold having at least one mold cavity, or a plurality of cavities formed in at least one major surface of the mold. In some examples, the mold is formed as a production tool, which can be, for example, a belt, a sheet, a continuous web, a coating roll such as a rotogravure roll, a sleeve mounted on a coating roll, or a die. In one example, the production tool can include polymeric material. Examples of suitable polymeric materials include thermoplastics such as polyesters, polycarbonates, poly(ether sulfone), poly(methyl methacrylate), polyurethanes, polyvinylchloride, polyolefin, polystyrene, polypropylene, polyethylene or combinations thereof, or thermosetting materials. In one example, the entire tooling is made from a polymeric or thermoplastic material. In another example, the surfaces of the tooling in contact with the precursor dispersion while the precursor dispersion is drying, such as the surfaces of the plurality of cavities, include polymeric or thermoplastic materials, and other portions of the tooling can be made from other materials. A suitable polymeric coating can be applied to a metal tooling to change its surface tension properties, by way of example.
A polymeric or thermoplastic production tool can be replicated off a metal master tool. The master tool can have the inverse pattern of that desired for the production tool. The master tool can be made in the same manner as the production tool. In one example, the master tool is made out of metal (e.g., nickel) and is diamond-turned. In one example, the master tool is at least partially formed using stereolithography. The polymeric sheet material can be heated along with the master tool such that the polymeric material is embossed with the master tool pattern by pressing the two together. A polymeric or thermoplastic material can also be extruded or cast onto the master tool and then pressed. The thermoplastic material is cooled to solidify and produce the production tool. If a thermoplastic production tool is utilized, then care should be taken not to generate excessive heat that can distort the thermoplastic production tool, limiting its life.
Access to cavities can be from an opening in the top surface or bottom surface of the mold. In some examples, the cavities can extend for the entire thickness of the mold. Alternatively, the cavities can extend only for a portion of the thickness of the mold. In one example, the top surface is substantially parallel to the bottom surface of the mold with the cavities having a substantially uniform depth. At least one side of the mold, the side in which the cavities are formed, can remain exposed to the surrounding atmosphere during the step in which the volatile component is removed.
The cavities have a specified three-dimensional shape to make shaped abrasive particle 300 or 400. The depth dimension is equal to the perpendicular distance from the top surface to the lowermost point on the bottom surface. The depth of a given cavity can be uniform or can vary along its length and/or width. The cavities of a given mold can be of the same shape or of different shapes.
A further operation involves filling the cavities in the mold with the precursor dispersion (e.g., by a conventional technique). In some examples, a knife roll coater or vacuum slot die coater can be used. A mold release agent can be used to aid in removing the particles from the mold if desired. Examples of mold release agents include oils such as peanut oil or mineral oil, fish oil, silicones, polytetrafluoroethylene, zinc stearate, and graphite. In general, a mold release agent such as peanut oil, in a liquid, such as water or alcohol, is applied to the surfaces of the production tooling in contact with the precursor dispersion such that from about 0.1 mg/in2 (0.6 mg/cm2) to about 3.0 mg/in2 (20 mg/cm2), or from about 0.1 mg/in2 (0.6 mg/cm2) to about 5.0 mg/in2 (30 mg/cm2), of the mold release agent is present per unit area of the mold when a mold release is desired. In some embodiments, the top surface of the mold is coated with the precursor dispersion. The precursor dispersion can be pumped onto the top surface.
In a further operation, a scraper or leveler bar can be used to force the precursor dispersion fully into the cavity of the mold. The remaining portion of the precursor dispersion that does not enter the cavity can be removed from the top surface of the mold and recycled. In some examples, a small portion of the precursor dispersion can remain on the top surface, and in other examples the top surface is substantially free of the dispersion. The pressure applied by the scraper or leveler bar can be less than 100 psi (0.6 MPa), or less than 50 psi (0.3 MPa), or even less than 10 psi (60 kPa). In some examples, no exposed surface of the precursor dispersion extends substantially beyond the top surface.
In those examples where it is desired to have the exposed surfaces of the cavities result in planar faces of the shaped abrasive particles, it can be desirable to overfill the cavities (e.g., using a micronozzle array) and slowly dry the precursor dispersion.
A further operation involves removing the volatile component to dry the dispersion. The volatile component can be removed by fast evaporation rates. In some examples, removal of the volatile component by evaporation occurs at temperatures above the boiling point of the volatile component. An upper limit to the drying temperature often depends on the material the mold is made from. For polypropylene tooling, the temperature should be less than the melting point of the plastic. In one example, for a water dispersion of from about 40 to 50 percent solids and a polypropylene mold, the drying temperatures can be from about 90° C. to about 165° C., or from about 105° C. to about 150° C., or from about 105° C. to about 120° C. Higher temperatures can lead to improved production speeds but can also lead to degradation of the polypropylene tooling, limiting its useful life as a mold.
During drying, the precursor dispersion shrinks, often causing retraction from the cavity walls. For example, if the cavities have planar walls, then the resulting shaped abrasive particle 300 or 400 can tend to have at least three concave major sides. It is presently discovered that by making the cavity walls concave (whereby the cavity volume is increased) it is possible to obtain shaped abrasive particle 300 or 400 that have at least three substantially planar major sides. The degree of concavity generally depends on the solids content of the precursor dispersion.
A further operation involves removing resultant precursor shaped abrasive particle 300 or 400 from the mold cavities. The precursor shaped abrasive particle 300 or 400 can be removed from the cavities by using the following processes alone or in combination on the mold: gravity, vibration, ultrasonic vibration, vacuum, or pressurized air to remove the particles from the mold cavities.
The precursor shaped abrasive particle 300 or 400 can be further dried outside of the mold. If the precursor dispersion is dried to the desired level in the mold, this additional drying step is not necessary. However, in some instances it can be economical to employ this additional drying step to minimize the time that the precursor dispersion resides in the mold. The precursor shaped abrasive particle 300 or 400 will be dried from 10 to 480 minutes, or from 120 to 400 minutes, at a temperature from 50° C. to 160° C., or 120° C. to 150° C.
A further operation involves calcining the precursor shaped abrasive particle 300 or 400. During calcining, essentially all the volatile material is removed, and the various components that were present in the precursor dispersion are transformed into metal oxides. The precursor shaped abrasive particle 300 or 400 is generally heated to a temperature from 400° C. to 800° C. and maintained within this temperature range until the free water and over 90 percent by weight of any bound volatile material are removed. In an optional step, it can be desirable to introduce the modifying additive by an impregnation process. A water-soluble salt can be introduced by impregnation into the pores of the calcined, precursor shaped abrasive particle 300 or 400. Then the precursor shaped abrasive particle 300 or 400 are pre-fired again.
A further operation can involve sintering the calcined, precursor shaped abrasive particle 300 or 400 to form particles 300 or 400. In some examples where the precursor includes rare earth metals, however, sintering may not be necessary. Prior to sintering, the calcined, precursor shaped abrasive particle 300 or 400 are not completely densified and thus lack the desired hardness to be used as shaped abrasive particle 300 or 400. Sintering takes place by heating the calcined, precursor shaped abrasive particle 300 or 400 to a temperature of from 1000° C. to 1650° C. The length of time for which the calcined, precursor shaped abrasive particle 300 or 400 can be exposed to the sintering temperature to achieve this level of conversion depends upon various factors, but from five seconds to 48 hours is possible.
In another embodiment, the duration of the sintering step ranges from one minute to 90 minutes. After sintering, the shaped abrasive particle 14 can have a Vickers hardness of 10 GPa (gigaPascals), 16 GPa, 18 GPa, 20 GPa, or greater.
Additional operations can be used to modify the described process, such as, for example, rapidly heating the material from the calcining temperature to the sintering temperature, and centrifuging the precursor dispersion to remove sludge and/or waste. Moreover, the process can be modified by combining two or more of the process steps if desired.
In addition to the materials already described, at least one magnetic material may be included within or coated to shaped abrasive particle 300 or 400. Examples of magnetic materials include iron; cobalt; nickel; various alloys of nickel and iron marketed as Permalloy in various grades; various alloys of iron, nickel and cobalt marketed as Fernico, Kovar, FerNiCo I, or FerNiCo II; various alloys of iron, aluminum, nickel, cobalt, and sometimes also copper and/or titanium marketed as Alnico in various grades; alloys of iron, silicon, and aluminum (about 85:9:6 by weight) marketed as Sendust alloy; Heusler alloys (e.g., Cu2MnSn); manganese bismuthide (also known as Bismanol); rare earth magnetizable materials such as gadolinium, dysprosium, holmium, europium oxide, alloys of neodymium, iron and boron (e.g., Nd2Fe14B), and alloys of samarium and cobalt (e.g., SmCo5); MnSb; MnOFe2O3; Y3Fe5O12; CrO2; MnAs; ferrites such as ferrite, magnetite; zinc ferrite; nickel ferrite; cobalt ferrite, magnesium ferrite, barium ferrite, and strontium ferrite; yttrium iron garnet; and combinations of the foregoing. In some embodiments, the magnetizable material is an alloy containing 8 to 12 weight percent aluminum, 15 to 26 wt % nickel, 5 to 24 wt % cobalt, up to 6 wt % copper, up to 1% titanium, wherein the balance of material to add up to 100 wt % is iron. In some other embodiments, a magnetizable coating can be deposited on an abrasive particle 300 or 400 using a vapor deposition technique such as, for example, physical vapor deposition (PVD) including magnetron sputtering.
Including these magnetizable materials can allow shaped abrasive particle 300 or 400 to be responsive a magnetic field. Any of shaped abrasive particles 300 or 400 can include the same material or include different materials.
In addition to shaped abrasive particles, binder pockets 200 of abrasive article 100 can also include conventional (e.g., crushed) abrasive particles. Examples of useful abrasive particles include fused aluminum oxide-based materials such as aluminum oxide, ceramic aluminum oxide (which can include one or more metal oxide modifiers and/or seeding or nucleating agents), and heat-treated aluminum oxide, silicon carbide, co-fused alumina-zirconia, diamond, ceria, titanium diboride, cubic boron nitride, boron carbide, garnet, flint, emery, sol-gel derived abrasive particles, and mixtures thereof. In some embodiments, binder pockets 200 can exclusively include conventional abrasive particles and are free of shaped abrasive particles.
The conventional abrasive particles can, for example, have an average diameter ranging from about 10 μm to about 2000 μm, about 20 μm to about 1300 μm, about 50 μm to about 1000 μm, less than, equal to, or greater than about 10 μm, 20, 30, 40, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1650, 1700, 1750, 1800, 1850, 1900, 1950, or 2000 μm. For example, the conventional abrasive particles can have an abrasives industry-specified nominal grade. Such abrasives industry-accepted grading standards include those known as the American National Standards Institute, Inc. (ANSI) standards, Federation of European Producers of Abrasive Products (FEPA) standards, and Japanese Industrial Standard (HS) standards Exemplary ANSI grade designations (e.g., specified nominal grades) include: ANSI 12 (1842 μm), ANSI 16 (1320 μm), ANSI 20 (905 μm), ANSI 24 (728 μm), ANSI 36 (530 μm), ANSI 40 (420 μm), ANSI 50 (351 μm), ANSI 60 (264 μm), ANSI 80 (195 μm), ANSI 100 (141 μm), ANSI 120 (116 μm), ANSI 150 (93 μm), ANSI 180 (78 μm), ANSI 220 (66 μm), ANSI 240 (53 μm), ANSI 280 (44 μm), ANSI 320 (46 μm), ANSI 360 (30 μm), ANSI 400 (24 μm), and ANSI 600 (16 μm). Exemplary FEPA grade designations include P12 (1746 μm), P16 (1320 μm), P20 (984 μm), P24 (728 μm), P30 (630 μm), P36 (530 μm), P40 (420 μm), P50 (326 μm), P60 (264 μm), P80 (195 μm), P100 (156 μm), P120 (127 μm), P120 (127 μm), P150 (97 μm), P180 (78 μm), P220 (66 μm), P240 (60 μm), P280 (53 μm), P320 (46 μm), P360 (41 μm), P400 (36 μm), P500 (30 μm), P600 (26 μm), and P800 (22 μm). An approximate average particles size of reach grade is listed in parenthesis following each grade designation.
Shaped abrasive particles 300 or 400 or crushed abrasive particles can include any suitable material or mixture of materials. For example, shaped abrasive particles 300 or 400 can include a material chosen from an alpha-alumina, a fused aluminum oxide, a heat-treated aluminum oxide, a ceramic aluminum oxide, a sintered aluminum oxide, a silicon carbide, a titanium diboride, a boron carbide, a tungsten carbide, a titanium carbide, a diamond, a cubic boron nitride, a garnet, a fused alumina-zirconia, a sol-gel derived abrasive particle, a cerium oxide, a zirconium oxide, a titanium oxide, and combinations thereof. In some embodiments, shaped abrasive particles 300 or 400 and crushed abrasive particles can include the same materials. In further embodiments, shaped abrasive particles 300 or 400 and crushed abrasive particles can include different materials.
Filler particles can also be included in binder pockets 200 or abrasive article 100. Examples of useful fillers include metal carbonates (such as calcium carbonate, calcium magnesium carbonate, sodium carbonate, magnesium carbonate), silica (such as quartz, glass beads, glass bubbles and glass fibers), silicates (such as talc, clays, montmorillonite, feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate), metal sulfates (such as calcium sulfate, barium sulfate, sodium sulfate, aluminum sodium sulfate, aluminum sulfate), gypsum, vermiculite, sugar, wood flour, a hydrated aluminum compound, carbon black, metal oxides (such as calcium oxide, aluminum oxide, tin oxide, titanium dioxide), metal sulfites (such as calcium sulfite), thermoplastic particles (such as polycarbonate, polyetherimide, polyester, polyethylene, poly(vinylchloride), polysulfone, polystyrene, acrylonitrile-butadiene-styrene block copolymer, polypropylene, acetal polymers, polyurethanes, nylon particles) and thermosetting particles (such as phenolic bubbles, phenolic beads, polyurethane foam particles and the like). The filler may also be a salt such as a halide salt. Examples of halide salts include sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroborate, sodium tetrafluoroborate, silicon fluorides, potassium chloride, magnesium chloride. Examples of metal fillers include tin, lead, bismuth, cobalt, antimony, cadmium, iron and titanium Other miscellaneous fillers include sulfur, organic sulfur compounds, graphite, lithium stearate and metallic sulfides. In some embodiments, individual shaped abrasive particles 300 or 400 or individual crushed abrasive particles can be at least partially coated with an amorphous, ceramic, or organic coating. Examples of suitable components of the coatings include, a silane, glass, iron oxide, aluminum oxide, or combinations thereof. Coatings such as these can aid in processability and bonding of the particles to a resin of a binder.
Including shaped abrasive particles 300 or 400 can allow for further tuning of the abrasive properties of abrasive article 100 in conjunction with the selective placement of binder pockets 200. For example, as shown in
As further shown in
The specific z-direction rotational orientation of formed abrasive particles can be achieved through use of a precision apertured screen that positions shaped abrasive particles 300 or 400 into a specific z-direction rotational orientation such that shaped abrasive particle 300 or 400 can only fit into the precision apertured screen in a few specific orientations such as less than or equal to 4, 3, 2, or 1 orientations. For example, a rectangular opening just slightly bigger than the cross section of shaped abrasive particle 300 or 400 comprising a rectangular plate will orient shaped abrasive particle 300 or 400 in one of two possible 180 degree opposed z-direction rotational orientations. The precision apertured screen can be designed such that shaped abrasive particles 300 or 400, while positioned in the screen's apertures, can rotate about their z-axis (normal to the screen's surface when the formed abrasive particles are positioned in the aperture) less than or equal to about 30, 20, 10, 5, 2, or 1 angular degrees.
The precision apertured screen having a plurality of apertures selected to z-directionally orient shaped abrasive particles 300 or 400 into a pattern, can have a retaining member such as adhesive tape on a second precision apertured screen with a matching aperture pattern, an electrostatic field used to hold the particles in the first precision screen or a mechanical lock such as two precision apertured screens with matching aperture patterns twisted in opposite directions to pinch particles 300 or 400 within the apertures. The first precision aperture screen is filled with shaped abrasive particles 300 or 400, and the retaining member is used to hold shaped abrasive particles 300 or 400 in place in the apertures. In one embodiment, adhesive tape on the surface of a second precision aperture screen aligned in a stack with the first precision aperture screen causes shaped abrasive particles 300 or 400 to stay in the apertures of the first precision screen stuck to the surface of the tape exposed in the second precision aperture screen's apertures.
Following positioning in apertures, coated backing 102 having binder 104 is positioned parallel to the first precision aperture screen surface containing the shaped abrasive particles 300 or 400 with binder 104 facing shaped abrasive particles 300 or 400 in the apertures. Thereafter, coated backing 102 and the first precision aperture screen are brought into contact to adhere shaped abrasive particles 300 or 400 to the binder 104. The retaining member is released such as removing the second precision aperture screen with taped surface, untwisting the two precision aperture screens, or eliminating the electrostatic field. Then the first precision aperture screen is then removed leaving the shaped abrasive particles 300 or 400 having a specified z-directional rotational orientation on the abrasive article 100 for further conventional processing such as applying a size coat 106 and curing the binder and size coat 104 and 106.
Abrasive article 100 can be manufactured according to many suitable procedures. As an example of a suitable procedure, backing 102, manufactured for example as described herein, can be provided. A saturant can optionally be applied to at least one of the first and second major surfaces of backing 102. Whether a saturant is applied or not, a subsequent step can include positioning a stencil or screen proximate to or in contact with the first or second major surface of backing 102.
The stencil or screen can generally be described as a mesh network. The mesh network defines a plurality of perforations or openings. The perforations or openings substantially correspond to the negative impression of the profile of binder pockets 200. Areas of the mesh network that are not open effectively serve as a mask for backing 102.
Once the stencil or screen is positioned over backing 102, a quantity of binder 104 is applied to the stencil or screen. Binder 104 is able to flow through the openings and adhere to backing 102 and create binding pockets 200 arranged in any of the predetermined patterns discussed herein. As mentioned herein, the rheological properties (e.g., viscosity) of the binder are controlled in such a manner that the viscosity of the binder is low enough to pass through the openings without adhering to the mesh network, but upon contact with backing 102, or shortly thereafter, it is able to adhere backing 102 and remain in the desired location.
After binder 104 is contacted with backing 102, any of the abrasive particles described herein are contacted with binder 104. In some examples, the abrasive particles can simply be drop-coated to binder 104. In other examples, orientation of abrasive particles can be controlled to a degree by electrostatic coating or through the use of the additional screens described herein that only allow an abrasive particle to pass through in a single orientation. According to various embodiments, it is possible to apply shaped abrasive particles 300 or 400 directly to backing 102 because shaped abrasive particles will only adhere to binder 104. Any abrasive particles 300 or 400 that contact an area of backing 102 that is free of a binder pocket 200 will not adhere to backing 102. Size coat 106 can optionally be applied to abrasive particles 300 or 400. The whole assembly can then be heated if needed to aid in curing any of binder 104 or size layer 106.
Various embodiments of the present disclosure can be better understood by reference to the following Examples which are offered by way of illustration. The present disclosure is not limited to the Examples given herein.
The components of the formulations used to prepare the abrasive articles described herein are listed in the following table.
A curable composition of a make coat and a size coat was prepared, under high speed dispersion, using a high shear blade between 600 rpm (revolutions per minute) to 900 rpm at room temperature, until a homogeneous mix was obtained, by blending Phenolic BB-077 with ALBERDINGK U 6150, then under shear adding GEO FM LTX, Black colorant, MINEX 10, MP22, Silane A187 and slowly adding CABOSIL M5.
A curable composition of make coat and size coat was prepared, under high speed dispersion, using a high shear blade between 600 revolutions per minute (rpm) to 900 rpm at room temperature, until a homogeneous mix was obtained, by blending ARCLIN 65-2024 with PERMAX 202, then under shear adding ADVANTAGE AM1512A anti-foamer, Black colorant, MINEX 10, MP22, Silane A187 and slowly adding CABOSIL M5. The catalyst aluminum chloride and salt ammonium chloride were added to the composition before coating of make coat or size coat.
A stencil printing process was used to make coat P80 grade abrasive. A patterned 10 mil polyester stencil film was placed over the PET spunbond fiber backing to produce the pattern shown in
In the case of Examples did need a size coat, the entire construction was then thermally pre-cured in a batch oven at 80° C. for 30 minutes and partially cured in a batch oven at 95° C. for one hour.
A stencil printing process was used to make coat P80 grade abrasive. Using a patterned 10 mil polyester stencil film placed over the PET spunbond fiber backing to produce the pattern shown in
In the case of Examples where a size coating is required, the entire construction was then thermally pre-cured in a batch oven at 65° C. for 30 minutes and partially cured.
For P120 grade abrasive prototypes a patterned 6 mils polyester film was used instead, the amount of curable composition was 120 gsm, having a film thickness of 150 microns, then 30 gram blend of 90% AlOx and 10% Kazbek PSG are electrostatically coated (Spellman SL 150). The following process are the same curing process previously described herein.
In the cases of Examples where a size coating is required, after the previously described process is performed, the prototypes are then kiss coated using PF Size coat in a two or three roll coater arrangement where 30 gsm of was used. The entire construction was then thermally pre-cured in a batch oven at 80° C. for 30 minutes and final cured in a batch oven at 103° C. for three hours
In the cases of Examples where size coating was required, after the processes described previously were done, the prototypes were then kiss coated using UF Size coat in a two or three roll coater arrangement where 30 gram is used. The entire construction was then thermally pre-cured in a batch oven at 65° C. for 30 minutes and final cured in a batch oven at 80° C. for three hours.
The rheological analysis in
A 5 inch (12.7 cm) diameter abrasive disc to be tested was mounted on an electric rotary tool that was disposed over an X-Y table having a plastic panel measuring 15 inches×21 inches×0.375 inch (38.1 m×53.3 cm×0.95 cm) secured to the X-Y table. The tool was then set to traverse at a rate of 5.5 inches/second (14.0 cm/sec) in the X direction along the length of the panel, and traverse along the width of the panel at a rate of 3 inches/second (7.6 cm/sec). The rotary tool was then activated to rotate at 8000 rpm under no load. The abrasive article was then urged at an angle of 2.5 degrees against the panel at a load of 10 lbs (4.54 kg). The tool was then activated to move along the length and width of the board. The tool was then raised, and returned to the starting point. Ten such grinding-and-return passes along the length of the panel were completed in each cycle for a total of 10 cycles. The mass of the panel was measured before and after each cycle to determine the total mass loss in grams after each cycle. A cumulative mass loss (total cut) was determined at the end of 10 cycles. The abrasive disc was weighed before and after the completion of the test (10 cycles) to determine the wear. The total cut and cut durability data for each Example provided in the Tables is an average of three samples that were tested. Cut durability was calculated: Cut Durability (%)=Final cut (Cycle 10)/Initial cut (Cycle 1)×100.
PET Fiber Spunbond (110 gram/square meter) are produced by depositing extruded, spun filaments onto a collecting belt in a uniform random manner followed by bonding the fibers. The fibers are separated during the web laying process by air jets or electrostatic charges.
Treatment of PET Fiber Substrate Samples with Saturant (SS)
The saturant solution was applied via a 2-roll coater for a wet add-on weight of 4 gram/24 in2. The saturated substrate was cured to a non-tacky condition by passing the 3M 5 coated web through a convection oven at 130° C. for 5 minutes, yielding a Saturated PET fiber spunbond substrate.
PET Fiber spunbond Substrate can be either treated with saturant or none treated. Abrasive discs were prepared with 80 and 120 grit abrasive particles, make coats and size coats or no size coats. Formulation PF1-PF4 phenolic-formaldehyde, filler, sheer thinning and wax based composition formulations according to the methods described above.
Phenolic-formaldehyde, filler, sheer thinning and wax based composition formulations Abrasive discs The make and size composition formulations are provided in Table 3.
PET Fiber spunbond Substrate can be either treated with saturant or none treated. Abrasive discs were prepared with 80 and 120 grit abrasive particles, make coats and size coats or no size coats. Formulation UF1-UF3 Urea-formaldehyde, filler, sheer thinning and wax based composition formulations according to the methods described above.
The make and size composition formulations are provided in Table 5.
The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the embodiments of the present disclosure. Thus, it should be understood that although the present disclosure has been specifically disclosed by specific embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of embodiments of the present disclosure.
The following exemplary embodiments are provided, the numbering of which is not to be construed as designating levels of importance:
Embodiment 1 provides an abrasive article comprising:
Embodiment 2 provides the abrasive article according to Embodiment 1, wherein the fiber component ranges from about 5 wt % to about 95 wt % of the abrasive article.
Embodiment 3 provides the abrasive article according to any one of Embodiments 1 or 2, wherein the fiber component ranges from about 50 wt % to about 95 wt % of the abrasive article.
Embodiment 4 provides the abrasive article according to any one of Embodiments 1-3, wherein individual fibers of the fiber component comprise a material chosen from a polyester, a nylon, a polypropylene, a polyethylene, a polyurethane, a polylactic acid, an acrylic, a rayon, a cellulose acetate, a polyvinylidene chloride-vinyl chloride copolymer, a vinyl chloride-acrylonitrile copolymer, and combinations thereof.
Embodiment 5 provides the abrasive article according to Embodiment 4, wherein the individual fibers of the fiber component comprise a polyethylene terephthalate.
Embodiment 6 provides the abrasive article according to any one of Embodiments 1-5, wherein the abrasive article is a non-compressed abrasive article.
Embodiment 7 provides the abrasive article according to any one of Embodiments 1-6, wherein the binder is chosen from a polyurethane resin, a polyurethane-urea resin, an epoxy resin, a urea-formaldehyde resin, a phenol-formaldehyde resin, and combinations thereof.
Embodiment 8 provides the abrasive article according to any one of Embodiments 1-7, wherein the binder ranges from about 10 wt % to about 70 wt % of the abrasive article.
Embodiment 9 provides the abrasive article according to any one of Embodiments 1-8, wherein the binder ranges from about 30 wt % to about 50 wt % of the abrasive article.
Embodiment 10 provides the abrasive article according to any one of Embodiments 1-9, wherein the first major surface or the second major surface independently comprise a substantially non-planar surface.
Embodiment 11 provides the abrasive article according to any one of Embodiments 1-10, wherein the abrasive particles range from about 5 wt % to about 70 wt % of the abrasive article.
Embodiment 12 provides the abrasive article according to any one of Embodiments 1-11, wherein the abrasive particles range from about 10 wt % to about 15 wt % of the abrasive article.
Embodiment 13 provides the abrasive article according to any one of Embodiments 1-12, wherein the abrasive particles are homogenously distributed throughout the abrasive article.
Embodiment 14 provides the abrasive article according to any one of Embodiments 1-13, wherein the abrasive particles are chosen from an alpha-alumina, a fused aluminum oxide, a heat-treated aluminum oxide, a ceramic aluminum oxide, a sintered aluminum oxide, a silicon carbide, a titanium diboride, a boron carbide, a tungsten carbide, a titanium carbide, a diamond, a cubic boron nitride, a garnet, a fused alumina-zirconia, a sol-gel derived abrasive particle, a cerium oxide, a zirconium oxide, a titanium oxide, and combinations thereof.
Embodiment 15 provides the abrasive article according to any one of Embodiments 1-14, wherein the abrasive particles are silicon carbide.
Embodiment 16 provides the abrasive article according to any one of Embodiments 1-15, wherein the abrasive particles are at least one of individual abrasive particles and agglomerates of abrasive particles.
Embodiment 17 provides the abrasive article according to any one of Embodiments 1-16, wherein the abrasive particles comprise a plurality of shaped abrasive particles.
Embodiment 18 provides the abrasive article according to Embodiment 17, wherein at least one of the shaped abrasive particles is tetrahedral and comprises four faces joined by six edges terminating at four tips, each one of the four faces contacting three of the four faces.
Embodiment 19 provides the abrasive article according to Embodiment 18, wherein at least one of the four faces is substantially planar.
Embodiment 20 provides the abrasive article according to any one of Embodiments 18 or 19, wherein at least one of the four faces is concave.
Embodiment 21 provides the abrasive article according to Embodiment 18, wherein all of the four faces are concave.
Embodiment 22 provides the abrasive article according to any one of Embodiments 18 or 21, wherein at least one of the four faces is convex.
Embodiment 23 provides the abrasive article according to Embodiment 18, wherein all of the four faces are convex.
Embodiment 24 provides the abrasive article according to any one of Embodiments 18-23, wherein at least one of the tetrahedral abrasive particles has equally-sized edges.
Embodiment 25 provides the abrasive article according to any one of Embodiments 18-24, wherein at least one of the tetrahedral abrasive particles has different-sized edges.
Embodiment 26 provides the abrasive article according to any one of Embodiments 1-25, wherein at least one of the shaped abrasive particles of the plurality of shaped abrasive particles comprises a first side and a second side separated by a thickness t, the first side comprises a first face having a triangular perimeter and the second side comprises a second face having a triangular perimeter, wherein the thickness t is equal to or smaller than the length of the shortest side-related dimension of the particle.
Embodiment 27 provides the abrasive article according to Embodiment 26, further comprising at least one sidewall connecting the first side and the second side.
Embodiment 28 provides the abrasive article according to Embodiment 27, wherein the at least one sidewall is a sloping sidewall.
Embodiment 29 provides the abrasive article according to any one of Embodiments 27 or 28, wherein a draft angle α of the sloping sidewall is in a range of from about 95 degrees and about 130 degrees.
Embodiment 30 provides the abrasive article according to any one of Embodiments 26-29, wherein the first face and the second face are substantially parallel to each other.
Embodiment 31 provides the abrasive article according to any one of Embodiments 26-30, wherein the first face and the second face are substantially non-parallel to each other.
Embodiment 32 provides the abrasive article according to any one of Embodiments 26-31, wherein at least one of the first and the second face are substantially planar.
Embodiment 33 provides the abrasive article according to any one of Embodiments 26-32, wherein at least one of the first and the second face is a non-planar face.
Embodiment 34 provides the abrasive article according to any one of Embodiments 1-33, wherein at least one of the shaped abrasive particles comprises at least one shape feature comprising: an opening, a concave surface, a convex surface, a groove, a ridge, a fractured surface, a low roundness factor, or a perimeter comprising one or more corner points having a sharp tip.
Embodiment 35 provides the abrasive article according to any one of Embodiments 1-34, wherein the abrasive particles comprise crushed abrasive particles.
Embodiment 36 provides the abrasive article according to Embodiment 35, wherein the abrasive article comprises a blend of shaped abrasive particles and crushed abrasive particles.
Embodiment 37 provides the abrasive article according to any one of Embodiments 35 or 36, wherein the shaped abrasive particles comprise 1 wt % to about 30 wt % of the blend.
Embodiment 38 provides the abrasive article according to any one of Embodiments 35 or 37, wherein the shaped abrasive particles comprise 5 wt % to about 15 wt % of the blend.
Embodiment 39 provides the abrasive article according to any one of Embodiments 1-38, wherein a portion of the abrasive particles form a predetermined pattern on the fibrous web.
Embodiment 40 provides the abrasive article according to Embodiment 39, wherein the portion of the abrasive particles that form a predetermined pattern are in a range of from about 25 wt % to about 100 wt % of the abrasive particles.
Embodiment 41 provides the abrasive article according to any one of Embodiments 39 or 40, wherein the portion of the abrasive particles that form a predetermined pattern are in a range of from about 50 wt % to about 80 wt % of the abrasive particles.
Embodiment 42 provides the abrasive article according to any one of Embodiments 39-41, wherein the predetermined pattern comprises a plurality of circles, substantially parallel lines, substantially curved lines, a plurality of hatchings, or a combination thereof.
Embodiment 43 provides the abrasive article according to any one of Embodiments 1-42, wherein a z-direction rotational angle about a line perpendicular to a major surface of the fibrous web and passing through individual shaped abrasive particles of the plurality of shaped abrasive particles is substantially the same for a portion of the plurality of shaped abrasive particles.
Embodiment 44 provides the abrasive article according to Embodiment 43, wherein the portion of the shaped abrasive particles having substantially the same z-direction rotational angle are in a range of from about 25 wt % to about 100 wt % of the plurality of shaped abrasive particles.
Embodiment 45 provides the abrasive article according to any one of Embodiments 43 or 44, wherein the portion of the shaped abrasive particles having substantially the same z-direction rotational angle are in a range of from about 50 wt % to about 80 wt % of the plurality of shaped abrasive particles.
Embodiment 46 provides the abrasive article according to any one of Embodiments 1-45, wherein about 50 wt % to about 100 wt % of the abrasive particles are oriented such that individual tip of an individual abrasive particle is oriented substantially upward relative to the first major surface or second major surface.
Embodiment 47 provides the abrasive article according to any one of Embodiments 1-46, wherein about 70 wt % to about 90 wt % of the abrasive particles are oriented such that individual tip of an individual abrasive particle is oriented substantially upward relative to the first major surface or second major surface.
Embodiment 48 provides the abrasive article according to any one of Embodiments 1-47, further comprising a saturant applied to the spunbond web.
Embodiment 49 provides the abrasive article according to Embodiment 48, wherein the saturant comprises a phenolic resin, an acrylic, a urea resin, or a mixture thereof.
Embodiment 50 provides the abrasive article according to any one of Embodiments 48 or 49, wherein the saturant includes a urea formaldehyde resin.
Embodiment 51 provides the abrasive article according to any one of Embodiments 48-50, wherein the saturant includes a urea formaldehyde resin and a compatible latex.
Embodiment 52 provides the abrasive article according to Embodiment 51, wherein the compatible latex comprises an acrylic emulsion.
Embodiment 53 provides the abrasive article according to any one of Embodiments 1-52, further comprising a size layer applied at least partially to the abrasive particles.
Embodiment 54 provides the abrasive article according to Embodiment 53, wherein the size layer comprises a size binder comprising phenolic resins, melamine resins, aminoplast resins having pendant α-, β-unsaturated carbonyl groups, urethane resins, epoxy resins, ethylenically unsaturated resins, acrylated isocyanurate resins, urea-aldehyde resins, isocyanurate resins, acrylated urethane resins, acrylated epoxy resins, bismaleimide resins, fluorene-modified epoxy resins, a urea formaldehyde resin, a phenolic formaldehyde resin, and a melamine formaldehyde resin, and combinations thereof.
Embodiment 55 provides the abrasive article according to any one of Embodiments 53 or 54, wherein the size layer further comprises wax.
Embodiment 56 provides the abrasive article according to any one of Embodiments 53-55, wherein the size layer further comprises a latex comprising natural rubber, butadiene rubber, styrene-butadiene rubber, styrene-butadieneacrylonitrile rubber, chloroprene rubber and methyl-butadiene rubber, cellulose and acrylic and vinyl acetate emulsions.
Embodiment 57 provides the abrasive article according to any one of Embodiments 1-56, further comprising a plurality of fumed silica particles.
Embodiment 58 provides the abrasive article according to Embodiment 57, wherein the plurality of fumed silica particles are in a range of from about 1 wt % to about 15 wt % of the abrasive article.
Embodiment 59 provides the abrasive article according to any one of Embodiments 57 or 58, wherein the plurality of fumed silica particles are in a range of from about 2 wt % to about 5 wt % of the abrasive article.
Embodiment 60 provides the abrasive article according to any one of Embodiments 1-59, wherein an average porosity of the fiber component is in a range of from about 10% to about 70%.
Embodiment 61 provides the abrasive article according to any one of Embodiments 1-60, wherein an average porosity of the fiber component is in a range of from about 20% to about 50%.
Embodiment 62 provides a method of forming the abrasive article according to any one of Embodiments 1-61, the method comprising:
Embodiment 63 provides the method according to Embodiment 62, further comprising applying the saturant to the spunbond web.
Embodiment 64 provides the method according to Embodiment 63, wherein the saturant is applied to the spunbond web before the binder is applied to the spunbond web.
Embodiment 65 provides the method according to any one of Embodiments 62-64, further comprising applying the size layer to the abrasive particles.
Embodiment 66 provides the method according to any one of Embodiments 62-65, wherein the abrasive particles are applied to the binder by drop coating or electrostatic coating.
Embodiment 67 provides the method according to any one of Embodiments 62-66, wherein the abrasive particles are passed through a second screen to achieve a desired orientation of the abrasive particles.
Embodiment 68 provides the method according to any one of Embodiments 62-67, wherein the screen comprises a continuous mesh that defines a plurality of perforations for the binder to pass through.
Embodiment 69 provides the method according to any one of Embodiments 62-68, wherein the initial viscosity is in a range of from about 10,000 cps to about 50,000 cps.
Embodiment 70 provides the method according to any one of Embodiments 62-69, wherein the initial viscosity is in a range of from about 10,000 cps to about 15,000 cps.
Embodiment 71 provides the method according to any one of Embodiments 62-70, wherein the final viscosity is in a range of from about 50,000 cps to about 1,000,000 cps.
Embodiment 72 provides the method according to any one of Embodiments 62-71, wherein the final viscosity is in a range of from about 150,000 cps to about 250,000 cps.
Embodiment 73 provides the method according to any one of Embodiments 62-72, further comprising applying a biasing member to the screen to force the binder through the screen.
Embodiment 74 provides the method according to any one of Embodiments 62-73, further comprising heating the binder.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/060866 | 11/18/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62937602 | Nov 2019 | US |
