US20230116900A1

US20230116900A1 - Abrasive Article

Info

Publication number: US20230116900A1
Application number: US17/906,362
Authority: US
Inventors: Junting LI; Yuyang Liu; Moses M. David; Jaime A. Martinez
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2020-03-18
Filing date: 2021-03-15
Publication date: 2023-04-13
Also published as: WO2021186326A1; EP4121249A1

Abstract

The disclosure relates to an abrasive article that includes a fabric substrate comprising strands forming first void spaces between the strands. The fabric substrate comprising an abrasive side and an attachment side. The abrasive article also includes a coating on the attachment side. The abrasive article also includes a make layer joined to the fabric substrate on the abrasive side. The abrasive article also includes abrasive particles joined to the make layer. The abrasive article also includes a plurality of second void spaces extending through the make layer coinciding with first void spaces in the fabric substrate. The coating on the fabric substrate is both hydrophobic and lipophobic. The attachment side of the fabric substrate is substantially free of make layer.

Description

BACKGROUND

It is very common for dry sanding operations to generate a significant amount of airborne dust. To minimize this airborne dust, it is common to use abrasive discs on a tool while vacuum is drawn through the abrasive disc, from the abrasive side through the backside of the disc, and into a dust-collection system. For this purpose, many abrasives are available with holes converted into them, to facilitate this dust extraction. As an alternative to converting dust-extraction holes into abrasive discs, commercial products exist in which the abrasive is coated onto fibers of a net-type knit backing in which loops are knit into the backside of the abrasive article. The loops serve as the loop-portion of a hook-and-loop attachment system for attachment to a tool. Net type products are known to provide superior dust extraction and/or anti-loading properties, when used with substrates known to severely load traditional abrasives. However, cut and/or life performance are still lacking. Thus, there is a need for a net type product that provides enhanced cut and/or life performance while demonstrating superior dust extraction.

SUMMARY

A disclosure relates to an abrasive article that includes a fabric substrate comprising strands forming first void spaces between the strands. The fabric substrate comprising an abrasive side and an attachment side. The abrasive article also includes a coating on the attachment side. The abrasive article also includes a make layer joined to the fabric substrate on the abrasive side. The abrasive article also includes abrasive particles joined to the make layer. The abrasive article also includes a plurality of second void spaces extending through the make layer coinciding with first void spaces in the fabric substrate. The coating on the fabric substrate is both hydrophobic and lipophobic. The attachment side of the fabric substrate is substantially free of make layer.
The above Summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure. Further features and advantages are disclosed in the embodiments that follow. The Drawings and the Detailed Description that follow more particularly exemplify certain embodiments using the principles disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

FIG. 1 is a perspective view of an abrasive article according to one example of the present disclosure.

FIG. 2 is a side cross-sectional view of abrasive articles according to various embodiments of the present disclosure.

FIG. 3 is a schematic showing the step-wise construction of abrasive articles according to various embodiments of the present disclosure.

FIGS. 4A-4I are side cross-sectional views of a portion of an abrasive article according to various embodiments of the present disclosure.

FIGS. 5-7 are side cross-sectional views of abrasive articles according to embodiments of the present disclosure.

FIG. 8 is a close-up view of an abrasive article made with heat activated adhesive according to embodiments of the present disclosure.

FIG. 9 is a schematic illustration of a method of making an abrasive article with heat activated adhesive according to embodiments of the present disclosure.

FIG. 10 is a method of making an abrasive article using heat activated adhesive according to embodiments of the present disclosure.

FIGS. 11A-11C illustrate steps in a method of making an abrasive article using heat activated adhesive according to embodiments of the present disclosure.

FIGS. 12A-12B illustrate close-up views of abrasive articles made with heat activated adhesive according to embodiments of the present disclosure.

FIGS. 13-15 illustrate examples of another method of making an abrasive article with shaped agglomerate abrasive structures according to embodiments of the present disclosure.

FIG. 16 illustrates a schematic of an abrasive article according to embodiments of the present disclosure.

FIGS. 17A-F illustrates coated abrasive articles according to embodiments of the present disclosure.

FIG. 18 illustrates a method of making coated abrasive articles according to embodiments of the present disclosure.

FIG. 19 illustrates coated abrasive articles described in the Examples.

It should be understood that numerous other modifications and examples can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. Figures may not be drawn to scale.

DESCRIPTION

Embodiments described herein are directed to an abrasive article that not only retains the dust-extraction advantages of an abrasive on a net-type backing, but also demonstrates abrasive performance (cut and/or life) advantages of a conventional abrasive. This combination of benefits (dust extraction and cut and/or life) is possible because the construction of the abrasive articles described herein allows for pattern-coating abrasive on a fabric backing to form well-defined areas of abrasive coating as well as open areas devoid of any abrasive coating. The patterned abrasive area can therefore be designed independent of any pattern present on the fabric substrate, to optimize both abrasive performance and dust extraction. Embodiments herein also apply to direct coating of abrasive articles, particularly net-type backed abrasive articles.
FIG. 1 is a perspective view of one example of an abrasive article referred to by the numeral 100. As shown, the abrasive article 100 includes: a fabric substrate 110 comprising strands forming first void spaces 270 between the strands (see FIG. 2 ); and an abrasive layer 120 joined to the fabric substrate 110; abrasive particles joined to the resin; and a plurality of void spaces extending through the fabric substrate 110 and the abrasive layer. The plurality of void spaces coinciding with void spaces in the fabric substrate 110 allow for an air flow through the article 100 at a rate of, e.g., at least 0.1 L/s (e.g. at least 0.2 Us, at least 0.4 L/s, at least 0.6 L/s, at least 1 L/s; or about 0.1 L/s to about 1 L/s, about 0.25 Us to about 0.75 L/s, about 0.5 L/s to about 1 L/s, about 1 L/s to about 2 L/s, about 1.5 L/s or about 3 L/s), such that, when in use, dust can be removed from an abraded surface through the abrasive article.
FIG. 1 illustrates one example of an abrasive article with large void spaces, according to PCT Application with Ser. No. 2020/050984, filed on Feb. 11, 2020, incorporated herein by reference. Said application discusses the benefits of a laminate, as illustrated in FIG. 1 . One such benefit of a laminate layer for a mesh backing is the prevention of bleed-through of the make resin to the attachment side of the abrasive article. However, methods and articles described herein illustrate that bleed-through can be avoided without a laminate layer. As described herein, it is possible to prevent bleed-through by treating an attachment side of the mesh with a hydro-lipophobic treatment that can repel the make coat, allowing for a continuous surface to form on the abrasive side.
FIG. 1 shows a relatively simple pattern that can be created with the abrasive layers 120. But the conceivable patterns are many. For example, abrasive articles 100 having various patterns in the abrasive layer 120 are shown in PCT Application with Ser. No. 2020/050984, filed on Feb. 11, 2020. As can be seen, the abrasive layers 120 can comprise a plurality of pattern elements 121, which may or may not be repeated across the surface of the abrasive article 100. Each pattern element 121 can be comprised of one or more sub-elements. Different pattern elements 121 within the same abrasive article may be provided with the same or different abrasive particles 250 or other additives (for example, different abrasive grades, blends of abrasive particles 250, fillers, grinding aids, etc.) as desired for a given application. Although the articles depicted are presented in the form of circular discs, it should be understood that abrasive articles could take any form (for example, sheets or belts).
FIG. 2 shows a cross-section of an abrasive article referred to by the numeral 100 taken on the line 2-2 of FIG. 1 looking in the direction of the arrows. As shown in FIG. 2 , the abrasive article 100 includes: a fabric substrate 110 comprising strands 260 forming first void spaces 270 between the strands 260; a hydro-lipophobic coating 230 joined to the fabric substrate 110 on an attachment side of substrate 110. A cured resin composition 240 (e.g., the cured product of a phenolic resin) is joined on the opposite side of the fabric substrate 110 from the hydro-lipophobic coating; abrasive particles 250 joined to the cured resin composition 240; and a plurality of second void spaces 280 extending through the coating and the make coat, coinciding with first void spaces 270 in the fabric substrate 110.
The abrasive particles 250 are at least partially embedded in the cured resin composition 240. As used herein, the term “at least partially embedded” generally means that at least a portion of an abrasive particle is embedded in the cured resin composition, such that, the abrasive particle is anchored in the cured resin composition. In some embodiments, abrasive particles 250 are coated in the form of a slurry composition. Abrasive particles 250 can optionally be oriented by influence of a magnetic field prior to the resin 240A being cured. See, for example, commonly-owned PCT Pub. Nos. 2018/080703, 2018/080756, 2018/080704, 2018/080705, 2018/080765, 2018/080784, 2018/136271, 2018/134732, 2018/080755, 2018/080799, 2018/136269, 2018/136268. In some other embodiments, abrasive particles 250 can optionally be placed using tools for controlled orientation and placement of abrasive particles. See, for example, commonly-owned PCT Pub. Nos. 2012/112305, 2015/100020, 2015/100220, 2015/100018, 2016/028683, 2016/089675, 2018/063962, 2018/063960, 2018/063958, 2019/102312, 2019/102328, 2019/102329, 2019/102330, 2019/102331, 2019/102332, 2016/205133, 2016/205267, 2017/007714, 2017/007703, 2018/118690, 2018/118699, 2018/118688, U.S. Pat. Pub. No. 2019-0275641, and U.S. Provisional Pat. Appl. Nos. 62/751,097, 62/767,853, 62/767,888, 62/780,987, 62/780,988, 62/780,994, 62/780,998, 62/781,009, 62/781,021, 62/781,037, 62/781,043, 62/781,057, 62/781,072, 62/781,077, 62/781,082, 62/825,938, 62/781,103.
Making reference to FIG. 2 , the abrasive article 100 comprises a first side 210 and a second side 212 opposite the first side 210. The second side 212 can include one part of a two-part hook and loop attachment system 213. The first side can include the abrasive particles within or embedded on a make resin layer. Bleed-through is prevented, in some embodiments, by coating the first side with a hydro-lipophobic coating layer that prevents the make resin from bleeding through, as discussed in greater detail below.
FIG. 3 shows an example of one method by which the abrasive article 100 shown in FIG. 1 can be constructed in step-wise fashion.
In a first step, a hydro-lipophobic coating layer is applied to fabric substrate 110 comprising strands 260 forming first void spaces 270 between the strands 260. The hydro-lipophobic coating can be applied to the fabric substrate 110 by any suitable means, including a plasma treatment, a spray coating, or a foam, such as a fluoro-chemical based foam.
In a second step, uncured resin composition 240A is joined to the fabric substrate 110 on a side opposite the hydro-lipophobic coating layer. The uncured resin composition 240A can be applied in any suitable method including by using a (rotary) stencil/screen printing roll, flatbed screen/stencil printing or by directly printing the uncured resin composition 240A onto the fabric substrate or by using combinations of two or more suitable methods (e.g., extrusion die coating, curtain coating, knife coating, gravure coating, and spray coating) for joining the uncured resin composition 240A to the fabric substrate 110.
In a third step, abrasive particles 250 are joined to the uncured resin composition 240A by any suitable method, including drop, pattern electrostatic, magnetic, and other mechanical methods of mineral coating. For example, abrasive particles 250 can be deposited onto uncured resin composition 240A by simply dropping the abrasive particles 250 onto the uncured resin composition 240A; by electrostatically depositing abrasive particles 250 onto the uncured resin composition 240A; or by using combinations of two or more suitable methods for joining the abrasive particles 250 to the uncured resin composition 240A. In some embodiments, the abrasive particles 250 can optionally be oriented under the influence of a magnetic field prior to the resin 240A being cured, as earlier indicated. The abrasive particles 250 may also be pattern coated on the uncured or partially cured resin composition.
In a fourth step, the uncured resin composition 240A is cured, this way abrasive particles 250 are at least partially embedded in the cured resin composition 240 and are substantially permanently attached. Uncured resin composition 240A can be cured to form cured resin 240 by any applicable curing mechanism, including thermal cure, photochemical cure, moisture-cured or combinations of two or more curing mechanism. But if the uncured resin composition 240A is cured by any means that does not include heating, a fifth step (not shown) may be necessary to fully open the void spaces 270 between strands 260.
During the curing process, at least a portion of cured resin composition 240 migrates away from the first void spaces 270 between strands 260, thereby opening a plurality of second void spaces 280 coinciding with first void spaces 270. Cured resin composition 240 is absent above the first void spaces 270. Although FIG. 3 shows an example of one method by which the abrasive article 100 shown in FIG. 1 can be constructed in step-wise fashion, methods are also contemplated where one or more of the steps described herein can be accomplished in a single step or wherein certain steps can be performed in an order different than what is shown in FIG. 3 .
In step 1, a coating 230 is applied to a first side of substrate 110. First side may be an attachment side including, for example, one part of a hook and loop attachment system. The coating may be a hydrophobic coating, for embodiments where the resin to be applied is a water-based resin. The coating may be a lipophobic coating, for embodiments where the resin to be applied is an organic-based resin. The hydro-lipophobic coating can be applied as a plasma treatment, for example. The hydrophobic coating may include fluorinated compounds, in some embodiments. The coating, in some embodiments, is a low-surface-energy coating features both hydrophobic and lipophobic features. The coating may be a fluorochemical coating, a silane coating, a silicone coating, or nano-surface treatment.
In step 2, make resin is applied to a second side of the substrate. Make resin may be pattern coated, as illustrated in FIG. 3 .
In step 3, abrasive particles 250 are coupled to the make resin.
FIGS. 4A-4I show the various permutations (not exhaustive) that can occur when the cured resin composition 240 is coated or otherwise migrates away from the first void spaces 270 between strands 260. For example, the cured resin 240 can at least partially wrap around the strands 260 to create second void spaces 280, thus leaving open the first void spaces 270 as shown in FIGS. 4B, 4D, 4F, 4G, 4H, and 4I. In such instances, the resin composition 240 extends over only the strands 260, not over first void spaces 270. And in some instances, the resin composition 240 can wrap around some stands 260 and not others, as shown in FIG. 4I.
FIG. 5 shows one example of an abrasive article referred to by the numeral 200, which incorporates all of the features shown in FIG. 1 , which will not be discussed again for the sake of brevity, but also a size coat 510 having size coat void spaces 520, which coincide with second void spaces 280. FIG. 6 shows one example of an abrasive article referred to by the numeral 300, which incorporates all of the features shown in FIG. 5 , which will not be discussed again for the sake of brevity, but also a supersize coat 610 having supersize coat void spaces 620, which coincide with size coat void spaces 520 and second void spaces 280.
The layer configurations described herein are not intended to be exhaustive, and it is to be understood that layers can be added or removed with respect to any of the examples depicted in FIGS. 1-3 .
The abrasive article of the various embodiments described herein include fabric substrate 110. Fabric substrate 110 may be constructed from any of a number of materials known in the art for making coated abrasive articles. Although not necessarily so limited, fabric substrate 110 can have a thickness of at least 0.02 millimeters, at least 0.03 millimeters, 0.05 millimeters, 0.07 millimeters, or 0.1 millimeters. The backing could have a thickness of up to 5 millimeters, up to 4 millimeters, up to 2.5 millimeters, up to 1.5 millimeters, or up to 0.4 millimeters.
Fabric substrate 110 can be flexible and has voids spaces (e.g., void spaces 270 between strands 260) such that it is porous. Flexible materials from which fabric substrate 110 can be made include cloth (e.g., cloth made from fibers or yarns comprising polyester, nylon, silk, cotton, and/or rayon, which may be woven, knit or stitch bonded) and scrim. The fabric substrate 110 can comprise a loop backing.
The abrasive layer of the abrasive article of the various embodiments described herein is made from a curable composition (e.g., uncured or partially cured resin composition 240A). In some instances, therefore, this specification makes reference to cured (e.g., cured resin composition 240) or uncured compositions (e.g., uncured or partially cured resin composition 240A), where the cured composition is synonymous with the abrasive layer 120.
The nature of the uncured or partially cured resin composition 240A that is converted to cured resin composition 240 is non-limiting, and can include, for example, any suitable additives or formulations described in PCT Application with Ser. No. IB2020/050984, filed Feb. 7, 2020.
In some embodiments, the curable compositions can contain one or more fiber reinforcement materials. The use of a fiber reinforcement material can provide an abrasive layer having improved cold flow properties, limited stretchability, and enhanced strength. Preferably, the one or more fiber reinforcement materials can have a certain degree of porosity that enables a photoinitiator, when present, to be dispersed throughout, to be activated by UV light, and properly cured without the need for heat. Further options and advantages of the fiber reinforcement materials are described in U.S. Patent Publication No. 2002/0182955 (Weglewski et al.).
While resin-based methods have been described thus far for attaching abrasive particles to a nonwoven abrasive article, it is also expressly contemplated that other methods may be possible. For example, FIGS. 8-12 illustrate another embodiment of the present invention in which a heat-activated adhesive is used to attach abrasive particles to a fiber backing.
FIG. 8 is a close-up view of an abrasive article made with heat activated adhesive according to embodiments of the present disclosure. FIG. 8 illustrates a mesh abrasive 1100 with a mesh backing 1110 onto which a heat activated adhesive 1120 has been applied. The heat activated adhesive can be applied on a nonwoven web and used to adhere abrasive particles without the use of an additional resin material. In one embodiment, an adhesive with a melting point above 170° is used. However, in other embodiments, adhesives with lower melting points can be used. The adhesive should have a melting point high enough that the adhesive will not melt during use of an abrasive article.
FIG. 9 is a schematic illustration of a method of making an abrasive article with heat activated adhesive according to embodiments of the present disclosure. Schematic images 1201A and 1251A illustrate a side view of backing showing the loops as attached to a single fiber. Schematic images 1201B and 1251B illustrate front views of three fibers in a mesh backing. While schematic images 1201A-B and 1251A-B illustrate only a few fibers 1230 for ease of understanding, it is understood that the concept applies to larger arrangements of fibers 1230.
A plurality of fibers 1230, each with one or more attached loops 1220, can be coated with a heat activated adhesive 1240. In one embodiment a heat activated adhesive film 1240 is laminated to fibers 1230. Adhesive film 1240 can be heated to a melting temperature, to ensure adhesion to fibers 1230, and cooled back down to room temperature. Abrasive particles 1210 can be applied to adhesive film 1240. For example, abrasive particles 1210 may be heated to a temperature high enough to soften adhesive film 1240, allowing abrasive particles 1210 to embed within adhesive layer 1240, as illustrated in schematic images 1251A and 1251B. Adhesive particles that do not attach to adhesive layer 1240 may fall through the voids in the fiber backing, as illustrated in FIG. 1251B.
While crushed abrasive particles are illustrated in FIG. 9 , it is expressly contemplated that the method illustrated can be applied to other abrasive particles, such as platey, formed, shaped, or partially shaped particles.
FIG. 10 is a method of making an abrasive article using heat activated adhesive according to embodiments of the present disclosure. Method 1300 may be useful for making abrasive articles.
In block 1310, a heat activated adhesive is applied to a backing. In one embodiment, the backing is a mesh backing. Applying a heat activated adhesive to a backing can include laminating the adhesive as a film, as indicated in block 1302, or directly coating the adhesive, as indicated in block 1304, or roll-coating the adhesive, as indicated in block 1306. Other application methods may also be used, as indicated in block 1308. Applying a heat-activated adhesive to a backing may also involve first heating the adhesive layer, as indicated in block 312, and then cooling the adhesive layer, as indicated in block 314.
In block 1320, abrasive grains are applied to the adhesive backing. Applying adhesive grains to the adhesive layer can include drop-coating methods, as indicated in block 1322, using a transfer tool, as indicated in block 1324, or other methods, as indicated in block 1326. For example, magnetically coated abrasive particles may be aligned on an adhesive-coated backing by applying a magnetic force. Additionally, abrasive particles may be coated using electrostatic forces.
The abrasive grains can be embedded into the adhesive layer by partially melting the heat-activated adhesive. This can be done by pre-heating the abrasive grains to a temperature higher than the melting point of the heat-activated adhesive, as indicated in block 1327. The potential cooling of the abrasive particles during transfer to the adhesive should be considered. Therefore, in some embodiments, the abrasive grains are heated to a temperature several degrees higher than the melting point to allow for cooling during the coating process. The adhesive-coated backing can be heated, either in addition to or as an alternative to heating the abrasive particles, as indicated in block 1328.
In block 1330, additives are applied. For example, multiple types of abrasive grains can be applied to the adhesive layer, as indicated in block 1332. For example, both precision shaped grains and crushed grains may be adhered to the adhesive layer. Alternatively, two different sizes of precision shaped grains may be applied to the adhesive layer. Additional functional layers may also be applied over the adhered abrasive grains, such as a size coat, as indicated in block 1334, or a supersize coat, as indicated in block 1336. Additional layers may also be included, as indicated in block 1338, such as a grinding aid or lubrication aid.
FIGS. 11A-11C illustrate steps in a method of making an abrasive article using heat activated adhesive according to embodiments of the present disclosure. FIG. 11A illustrates a mesh backing 1400 with a plurality of fibers 1410. FIG. 11B illustrates a mesh backing 1450 where a heat activated adhesive 1420 has been applied to portions of fibers 1410 of mesh backing 1450. FIG. 11C illustrates a mesh backing 1480 coated with precision-shaped abrasive particles 1430. The precision-shaped particles 1430 of FIG. 11C are triangle-shaped, however other shapes are also expressly envisioned for other embodiments.
FIGS. 12A-12B illustrate close-up views of abrasive articles made with heat activated adhesive according to embodiments of the present disclosure. FIG. 12A illustrates a view of a mesh backing coated with P100 aluminum-zirconia abrasive particles. FIG. 12B illustrates a mesh backing coated with precision-shaped grain that was applied by heating the mesh backing to 155° C. before drop-coating the particles. However, it is also expressly contemplated that the particles, instead of or in addition to the mesh backing, could be pre-heated before application.
A wide variety of abrasive particles may be utilized in the various embodiments described herein. The particular type of abrasive particle (e.g. size, shape, chemical composition) is not considered to be particularly significant to the abrasive article, so long as at least a portion of the abrasive particles are suitable for the intended end-use application. Suitable abrasive particles may be formed of, for example, cubic boron nitride, zirconia, alumina, silicon carbide and diamond.
The abrasive particles may be provided in a variety of sizes, shapes and profiles, including, for example, random or crushed shapes, regular (e.g. symmetric) profiles such as square, star-shaped or hexagonal profiles, and irregular (e.g. asymmetric) profiles.
The abrasive article may include a mixture of abrasive particles that are inclined on the backing (i.e. stand upright and extend outwardly from the backing) as well as abrasive particles that lie flat on their side (i.e. they do not stand upright and extend outwardly from the backing).
The abrasive article may include a mixture of different types of abrasive particles. For example, the abrasive article may include mixtures of platey and non-platey particles, crushed, agglomerated, and shaped particles (which may be discrete abrasive particles that do not contain a binder or agglomerate abrasive particles that contain a binder), conventional non-shaped and non-platey abrasive particles (e.g. filler material) and abrasive particles of different sizes.
Examples of different types of agglomerate based abrasive articles on a mesh backing can be seen in FIGS. 13-15 . FIGS. 13A-13D illustrate abrasive agglomerate particles on a mesh backing. As illustrated in FIG. 13A, an agglomerate abrasive particle 1700 includes abrasive grains 1710 and can have one or more agglomerate shape features. Agglomerate abrasive particle 1700, as illustrated in FIG. 13A, may also include a second type of abrasive particle 1720.
In one embodiment, abrasive agglomerate 1700 can be defined as having a width, w, a thickness, h, with a ratio of w/h being higher than 2. In a preferred embodiment, the width is higher than 5. In some embodiments, the width of the agglomerate is larger than 1000 μm. The abrasive agglomerates, as illustrated in FIGS. 13A-13D may be at least partially precisely shaped. The shapes may include, but are not limited to, nonagon, octagon, heptagon, hexagon, triangle (scalene, acute, obtuse, isosceles, equilateral, or right), parallelogram, rhombus, rectangle, square, pentagon, circle, oval, heart, cross, arrow, star (with any number of points from 3, as illustrated in FIG. 13A, to 10), or crescent.
Abrasive agglomerate particles such as those illustrated in FIGS. 13A-13D may be especially useful for making mesh abrasive articles. As illustrated in FIG. 13B, at least one dimension of the abrasive particle 1700 is greater than the gaps in mesh backing 1750, ensuring that abrasive agglomerates do not fall through the mesh backing.
As illustrated in FIGS. 13C and 13D, abrasive agglomerate particles 1760 may comprise abrasive particles 1764 within a resin bond 1762. The abrasive agglomerate particles may be placed on a backing 1750 in a pattern, or dropped in a random configuration. This can give the benefit of a ‘patterned’ abrasive structure, as each individual agglomerate has a shape, but also the benefits of random placement, which may reduce scratches or cut patterns on an abraded worksurface. Additionally, systems and methods herein can also apply to direct coating methods of abrasives and resins.
FIG. 14 illustrates one schematic method of making a mesh abrasive article with agglomerate abrasive particles. The agglomerates 1830 may be premade, for example, using methods of making agglomerates described in U.S. PAP 2019/0283216, published on Sep. 19, 2019 and U.S. PAP 2017/058254 (describing vitrified shaped agglomerates), and PCT Publication WO 2019/0167022, published Sep. 6, 2019 (describing siliceous bond agglomerates), as well as US PAP 2019/0270922, published Sep. 5, 2019, all of which are incorporated herein by reference. Once made, the agglomerates may proceed, as indicated in direction 1850, on a conveyance mechanism 1840. While a horizontal conveyance mechanism 1840 is illustrated, it is expressly contemplated that a tilted conveyance mechanism 1840, or other suitable deposition mechanisms, such as a drop coater or other suitable mechanism for depositing the agglomerates 1830 in a pattern or random configuration.
A backing 1810 proceeds, also in direction 1850 in one embodiment, on a conveyance mechanism. Backing 1810 may have a make coat 1820 applied such that deposited abrasive agglomerates 1830. Make coat 1820 may include a make resin, a blown melty film, or a hot melt adhesive, for example.
FIGS. 15A and 15B illustrate linear abrasive agglomerates that may also be useful in mesh abrasive article formation. As illustrated in FIG. 15B, the linear abrasive agglomerate has at least one dimension that is longer than a gap between mesh fibers, ensuring that the abrasive agglomerate will adhere to a make resin layer on the abrasive article.
Examples of suitable shaped abrasive particles can be found in, for example, U.S. Pat. No. 5,201,916 (Berg) and U.S. Pat. No. 8,142,531 (Adefris et al.) A material from which the shaped abrasive particles may be formed comprises alpha alumina. Alpha alumina shaped abrasive particles can be made from a dispersion of aluminum oxide monohydrate that is gelled, molded to shape, dried to retain the shape, calcined, and sintered according to techniques known in the art.
Examples of suitable shaped abrasive particles can also be found in Published U.S. Appl. No. 2015/0267097, which is incorporated herein by reference. Published U.S. Appl. No. 2015/0267097 generally describes abrasive particles comprising alpha alumina having an average crystal grain size of 0.8 to 8 microns and an apparent density that is at least 92 percent of the true density. Each shaped abrasive particle can have a respective surface comprising a plurality of smooth sides that form at least four vertexes.
U.S. Pat. No. 8,034,137 (Erickson et al.) describes alumina abrasive particles that have been formed in a specific shape, then crushed to form shards that retain a portion of their original shape features. In some embodiments, shaped alpha alumina particles are precisely-shaped (i.e., the particles have shapes that are at least partially determined by the shapes of cavities in a production tool used to make them). Details concerning such shaped abrasive particles and methods for their preparation can be found, for example, in U.S. Pat. No. 8,142,531 (Adefris et al.); U.S. Pat. No. 8,142,891 (Culler et al.); and U.S. Pat. No. 8,142,532 (Erickson et al.); and in U.S. Pat. Appl. Publ. Nos. 2012/0227333 (Adefris et al.); 2013/0040537 (Schwabel et al.); and 2013/0125477 (Adefris).
Examples of suitable crushed abrasive particles include crushed abrasive particles comprising fused aluminum oxide, heat-treated aluminum oxide, white fused aluminum oxide, ceramic aluminum oxide materials such as those commercially available as 3M CERAMIC ABRASIVE GRAIN from 3M Company, St. Paul, Minn., brown aluminum oxide, blue aluminum oxide, silicon carbide (including green silicon carbide), titanium diboride, boron carbide, tungsten carbide, titanium carbide, diamond, cubic boron nitride, garnet, fused alumina zirconia, iron oxide, chromia, zirconia, titania, tin oxide, quartz, feldspar, flint, emery, sol-gel-derived ceramic (e.g., alpha alumina), and combinations thereof. Further examples include crushed abrasive composites of abrasive particles (which may be platey or not) in a binder matrix, such as those described in U.S. Pat. No. 5,152,917 (Pieper et al.).
Examples of sol-gel-derived abrasive particles from which crushed abrasive particles can be isolated, and methods for their preparation can be found in U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951 (Monroe et al.). It is also contemplated that the crushed abrasive particles could comprise abrasive agglomerates such as, for example, those described in U.S. Pat. No. 4,652,275 (Bloecher et al.) or U.S. Pat. No. 4,799,939 (Bloecher et al.).
The crushed abrasive particles comprise ceramic crushed abrasive particles such as, for example, sol-gel-derived polycrystalline alpha alumina particles. Ceramic crushed abrasive particles composed of crystallites of alpha alumina, magnesium alumina spinel, and a rare earth hexagonal aluminate may be prepared using sol-gel precursor alpha alumina particles according to methods described in, for example, U.S. Pat. No. 5,213,591 (Celikkaya et al.) and U.S. Publ. Pat. Appln. Nos. 2009/0165394 A1 (Culler et al.) and 2009/0169816 A1 (Erickson et al.).
Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Pat. No. 4,314,827 (Leitheiser); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,435,816 (Spurgeon et al.); U.S. Pat. No. 5,672,097 (Hoopman et al.); U.S. Pat. No. 5,946,991 (Hoopman et al.); U.S. Pat. No. 5,975,987 (Hoopman et al.); and U.S. Pat. No. 6,129,540 (Hoopman et al.); and in U.S. Patent Publication No. 2009/0165394 A1 (Culler et al.). Examples of suitable platey crushed abrasive particles can be found in, for example, U.S. Pat. No. 4,848,041 (Kruschke).
The abrasive particles may be surface-treated with a coupling agent (e.g., an organosilane coupling agent) or other physical treatment (e.g., iron oxide or titanium oxide) to enhance adhesion of the crushed abrasive particles to the binder.
The abrasive layer, in some embodiments, includes a particulate mixture comprising a plurality of formed abrasive particles (e.g., precision shaped grain (PSG) mineral particles available from 3M, St. Paul, Minn., which are described in greater detail herein; not shown in FIGS. 1-3 ) and a plurality of abrasive particles 250, or only formed abrasive particles, adhesively secured to the abrasive layer.
In some embodiment, the abrasive particles may be formed abrasive particles. As used herein, the term “formed abrasive particles” generally refers to abrasive particles (e.g., formed ceramic abrasive particles) having at least a partially replicated shape. Non-limiting examples of formed abrasive particles are disclosed in Published U.S. Patent Appl. No. 2013/0344786, which is incorporated by reference as if fully set forth herein. Non-limiting examples of formed abrasive particles include shaped abrasive particles formed in a mold, such as triangular plates as disclosed in U.S. Pat. Nos. RE 35,570; U.S. Pat. Nos. 5,201,916, and 5,984,998 all of which are incorporated by reference as if fully set forth herein; or extruded elongated ceramic rods/filaments often having a circular cross section produced by Saint-Gobain Abrasives an example of which is disclosed in U.S. Pat. No. 5,372,620, which is incorporated by reference as if fully set forth herein. Formed abrasive particle as used herein excludes randomly sized abrasive particles obtained by a mechanical crushing operation.
Formed abrasive particles also include shaped abrasive particles. As used herein, the term “shaped abrasive particle,” generally refers to abrasive particles with at least a portion of the abrasive particles having a predetermined shape that is replicated from a mold cavity used to form the shaped precursor abrasive particle. Except in the case of abrasive shards (e.g. as described in U.S. patent publication US 2009/0169816), the shaped abrasive particle will generally have a predetermined geometric shape that substantially replicates the mold cavity that was used to form the shaped abrasive particle. Shaped abrasive particle as used herein excludes randomly sized abrasive particles obtained by a mechanical crushing operation.
Formed abrasive particles also include precision-shaped grain (PSG) mineral particles, such as those described in Published U.S. Appl. No. 2015/267097, which is incorporated by reference as if fully set forth herein.
Examples of suitable abrasive particles include, for example, fused aluminum oxide, heat treated aluminum oxide, white fused aluminum oxide, black silicon carbide, green silicon carbide, titanium diboride, boron carbide, silicon nitride, tungsten carbide, titanium carbide, diamond, cubic boron nitride, hexagonal boron nitride, garnet, fused alumina zirconia, alumina-based sol gel derived abrasive particles, silica, iron oxide, chromia, ceria, zirconia, titania, tin oxide, gamma alumina, and mixtures thereof. The alumina abrasive particles may contain a metal oxide modifier. The diamond and cubic boron nitride abrasive particles may be monocrystalline or polycrystalline.
In some examples, the formed abrasive particles have a substantially monodisperse particle size of from about 1 micrometers to about 5000 micrometers, from about 1 micrometers to about 2500, from about 1 micrometers to about 1000, from about 10 micrometers to about 5000, from about 10 micrometers to about 2500, from about 10 micrometers to about 1000, from about 50 micrometers to about 5000, from about 50 micrometers to about 2500, from about 50 micrometers to about 1000. As used herein, the term “substantially monodisperse particle size” is used to describe formed abrasive particles having a size that does not vary substantially. Thus, for example, when referring to formed abrasive particles (e.g., a PSG mineral particles) having a particle size of 100 micrometers, greater than 90%, greater than 95% or greater than 99% of the formed abrasive particles will have a particle having its largest dimension be 100 micrometers.
In some embodiments, the abrasive particles can have a range or distribution of particle sizes. Such a distribution can be characterized by its median particle size. For instance, the median particle size of the abrasive particles may be at least 0.001 micrometers, at least 0.005 micrometers, at least 0.01 micrometers, at least 0.015 micrometers, or at least 0.02 micrometers. In some instances, the median particle size of the abrasive particles may be up to 300 micrometers, up to 275 micrometers, up to 250 micrometers, up to 150 micrometers, or up to 100 micrometers. In some examples, the median particle size of the abrasive particles is from about 1 micrometers to about 600 micrometers, from about 1 micrometers to about 300 micrometers, from about 1 micrometers to about 150 micrometers, from about 10 micrometers to about 600 micrometers, from about 10 micrometers to about 300 micrometers, from about 10 micrometers to about 150 micrometers, from about 50 micrometers to about 600 micrometers, from about 50 micrometers to about 300 micrometers, from about 50 micrometers to about 150 micrometers.
In some examples, the abrasive particle of the present disclosure may include formed abrasive particles. The formed abrasive particles may be present from 0.01 wt. percent to 100 wt, percent, from 0.1 wt. percent to 100 wt, percent, from 1 wt. percent to 100 wt, from 10 wt. percent to 100 wt, percent, from 0.01 wt. percent to 90 wt, percent, from 0.1 wt. percent to 90 wt, percent, from 1 wt. percent to 90 wt, from 10 wt. percent to 90 wt, percent, from 0.01 wt. percent to 75 wt, percent, from 0.1 wt. percent to 75 wt, percent, from 1 wt. percent to 75 wt, from 10 wt. percent to 75 wt, percent, based on the total weight of the abrasive particles.
In some examples, the particulate mixture comprises from about greater than 90 wt. % to about 99 wt. % abrasive particles (e.g., from about 91 wt. % to about 97 wt. %; about 92 wt. % to about 97 wt. %; about 95 wt. % to about 97 wt. %; or greater than about 90 wt. % to about 97 wt. %).
In some embodiments, the abrasive article of the various embodiments described herein include a size coat 510. See FIG. 5 . In some examples, the size coat comprises the cured product of a phenolic size composition. In other examples, the size coat comprises the cured (e.g., photopolymerized) product of a bis-epoxide (e.g., 3,4-epoxy cyclohexylmethyl-3,4-epoxy cyclohexylcarboxylate, available from Daicel Chemical Industries, Ltd., Tokyo, Japan); a trifunctional acrylate (e.g., trimethylol propane triacrylate, available under the trade designation “SR351” from Sartomer USA, LLC, Exton, Pa.); an acidic polyester dispersing agent (e.g., “BYK W-985” from Byk-Chemie, GmbH, Wesel, Germany); a filler (e.g., a sodium-potassium alumina silicate filler, obtained under the trade designation “MINEX 10” from The Cary Company, Addison, Ill.); a photoinitiator (e.g., a triarylsulfonium hexafluoroantimonate/propylene carbonate photoinitiator, obtained under the trade designation “CYRACURE CPI 6976” from Dow Chemical Company, Midland, Mich.; and an α-Hydroxyketone photoinitiator, obtained under the trade designation “DAROCUR 1173” from BASF Corporation, Florham Park, N.J.).
In some embodiments, the abrasive article of the various embodiments described include a supersize coat 610. See FIG. 6 . In general, the supersize coat is the outermost coating of the abrasive article and directly contacts the workpiece during an abrading operation. The supersize coat is, in some examples, substantially transparent.
The term “substantially transparent” as used herein refers to a majority of, or mostly, as in at least about 30%, 40%, 50%, 60%, or at least about 70% or more transparent. In some examples, the measure of the transparency of any given coat described herein (e.g., the supersize coat) is the coat's transmittance. In some examples, the supersize coat displays a transmittance of at least 5 percent, at least 20 percent, at least 40 percent, at least 50 percent, or at least 60 percent (e.g., a transmittance from about 40 percent to about 80 percent; about 50 percent to about 70 percent; about 40 percent to about 70 percent; or about 50 percent to about 70 percent), according to a Transmittance Test that measures the transmittance of 500 nm light through a sample of 6 by 12 inch by approximately 1-2 mil (15.24 by 30.48 cm by 25.4-50.8 μm) clear polyester film, having a transmittance of about 98%.
One component of supersize coats can be a metal salt of a long-chain fatty acid (e.g., a C₁₂-C₂₂fatty acid, a C₁₄-C₁₈fatty acid, and a C₁₆-C₂₀fatty acid). In some examples, the metal salt of a long-chain fatty acid is a stearate salt (e.g., a salt of stearic acid). The conjugate base of stearic acid is C₁₇H₃₅COO—, also known as the stearate anion. Useful stearates include, but are not limited to, calcium stearate, zinc stearate, and combinations thereof.
The metal salt of a long-chain fatty acid can be present in an amount of at least 10 percent, at least 50 percent, at least 70 percent, at least 80 percent, or at least 90 percent by weight based on the normalized weight of the supersize coat (i.e., the average weight for a unit surface area of the abrasive article). The metal salt of a long-chain fatty acid can be present in an amount of up to 100 percent, up to 99 percent, up to 98 percent, up to 97 percent, up to 95 percent, up to 90 percent, up to 80 percent, or up to 60 percent by weight (e.g., from about 10 wt. % to about 100 wt. %; about 30 wt. % to about 70 wt. %; about 50 wt. % to about 90 wt. %; or about 50 wt. % to about 100 wt. %) based on the normalized weight of the supersize coat.
Another component of the supersize coat is a polymeric binder, which, in some examples, enables the supersize coat to form a smooth and continuous film over the abrasive layer. In one example, the polymeric binder is a styrene-acrylic polymer binder. In some examples, the styrene-acrylic polymer binder is the ammonium salt of a modified styrene-acrylic polymer, such as, but not limited to, JONCRYL® LMV 7051. The ammonium salt of a styrene-acrylic polymer can have, for example, a weight average molecular weight (Mw) of at least 100,000 g/mol, at least 150,000 g/mol, at least 200,000 g/mol, or at least 250,000 g/mol (e.g., from about 100,000 g/mol to about 2.5×106 g/mol; about 100,000 g/mol to about 500,000 g/mol; or about 250,000 to about 2.5×106 g/mol).
The minimum film-forming temperature, also referred to as MFFT, is the lowest temperature at which a polymer self-coalesces in a semi-dry state to form a continuous polymer film. In the context of the present disclosure, this polymer film can then function as a binder for the remaining solids present in the supersize coat. In some examples, the styrene-acrylic polymer binder (e.g., the ammonium salt of a styrene-acrylic polymer) has an MFFT that is up to 90° C., up to 80° C., up to 70° C., up to 65° C., or up to 60° C.
In some examples, the binder is dried at relatively low temperatures (e.g., at 70° C. or less). The drying temperatures are, in some examples, below the melting temperature of the metal salt of a long-chain fatty acid component of the supersize coat. Use of excessively high temperatures (e.g., temperatures above 80° C.) to dry the supersize coat is undesirable because it can induce brittleness and cracking in the backing, complicate web handling, and increase manufacturing costs. By virtue of its low MFFT, a binder comprised of, e.g., the ammonium salt of a styrene-acrylic polymer allows the supersize coat to achieve better film formation at lower binder levels and at lower temperatures without need for added surfactants such as DOWANOL® DPnP.
The polymeric binder can be present in an amount of at least 0.1 percent, at least 1 percent, or at least 3 percent by weight, based on the normalized weight of the supersize coat. The polymeric binder can be present in an amount of up to 20 percent, up to 12 percent, up to 10 percent, or up to 8 percent by weight, based on the normalized weight of the supersize coat. Advantageously, when the ammonium salt of a modified styrene acrylic copolymer is used as a binder, the haziness normally associated with a stearate coating is substantially reduced.
The supersize coats of the present disclosure optionally contain clay particles dispersed in the supersize coat. The clay particles, when present, can be uniformly mixed with the metal salt of a long chain fatty acid, polymeric binder, and other components of the supersize composition. The clay can bestow unique advantageous properties to the abrasive article, such as improved optical clarity and improved cut performance. The inclusion of clay particles can also enable cut performance to be sustained for longer periods of time relative to supersize coats in which the clay additive is absent.
The clay particles, when present, can be present in an amount of at least 0.01 percent, at least 0.05 percent, at least 0.1 percent, at least 0.15 percent, or at least 0.2 percent by weight based on the normalized weight of the supersize coat. Further, the clay particles can be present in an amount of up to 99 percent, up to 50 percent, up to 25 percent, up to 10 percent, or up to 5 percent by weight based on the normalized weight of the supersize coat.
The clay particles may include particles of any known clay material. Such clay materials include those in the geological classes of the smectites, kaolins, illites, chlorites, serpentines, attapulgites, palygorskites, vermiculites, glauconites, sepiolites, and mixed layer clays. Smectites in particular include montmorillonite (e.g., a sodium montmorillonite or calcium montmorillonite), bentonite, pyrophyllite, hectorite, saponite, sauconite, nontronite, talc, beidellite, and volchonskoite. Specific kaolins include kaolinite, dickite, nacrite, antigorite, anauxite, halloysite, indellite and chrysotile. Illites include bravaisite, muscovite, paragonite, phlogopite and biotite. Chlorites can include, for example, corrensite, penninite, donbassite, sudoite, pennine and clinochlore. Mixed layer clays can include allevardite and vermiculitebiotite. Variants and isomorphic substitutions of these layered clays may also be used.
As an optional additive, abrasive performance may be further enhanced by nanoparticles (i.e., nanoscale particles) interdispersed (e.g., in the clay particles) in the supersize coat. Useful nanoparticles include, for example, nanoparticles of metal oxides, such as zirconia, titania, silica, ceria, alumina, iron oxide, vanadia, zinc oxide, antimony oxide, tin oxide, and alumina-silica. The nanoparticles can have a median particle size of at least 1 nanometer, at least 1.5 nanometers, or at least 2 nanometers. The median particle size can be up to 200 nanometers, up to 150 nanometers, up to 100 nanometers, up to 50 nanometers, or up to 30 nanometers.
Other optional components of the supersize composition include curing agents, surfactants, antifoaming agents, biocides, and other particulate additives known in the art for use in supersize compositions.
The supersize coat can be formed, in some examples, by providing a supersize composition in which the components are dissolved or otherwise dispersed in a common solvent. In some examples, the solvent is water. After being suitably mixed, the supersize dispersion can be coated onto the underlying layers of the abrasive article and dried to provide the finished supersize coat. If a curing agent is present, the supersize composition can be cured (e.g., hardened) either thermally or by exposure to actinic radiation at suitable wavelengths to activate the curing agent.
The coating of the supersize composition onto, e.g., the abrasive layer can be carried out using any known process. In some examples, the supersize composition is applied by spray coating at a constant pressure to achieve a pre-determined coating weight. Alternatively, a knife coating method where the coating thickness is controlled by the gap height of the knife coater can be used.
FIG. 16 illustrates schematic views of a strand 2020 within a coated abrasive article 2000. A single strand 2020 has a make coat 2030 deposited on one side, to which abrasive particles 2040 are adhered. In one embodiment, a fabric substrate 202 has an attachment system, such as looks 2010, adhered to a side opposing the abrasive particles.
Abrasive articles can be made using fabric substrates with strands, such as strand 2020 of FIG. 16 , in an open weave, with large openings separating adjoining strands. Applying a standard make resin 2030 is difficult on an open backing without complex coating equipment or process. Systems and methods are desired to allow placement of make resin 2030 on an open mesh backing 2020 using knife or roller coating.
One problem with applying traditional coating methods to an open mesh backing is the force of gravity 2050 applied on the make coat 2030 during application and curing, causing make coat 2030 to bleed through backing 2020 and onto the loop attachment system 2010. This can interfere with attachment system 2010 functionally coupling article 2000 to an abrading system.
In some embodiments described herein, a coating or treatment is applied to a backing of an abrasive article to induce partial, temporary, or permanent hydro-lipophobicity that can reduce the surface energy of the backside of the backing and prevent the make resin from wicking the backside of the backing and the sidewalls of individual strands within the backing. Hydrophobicity is desired for make resins that are at least partially aqueous in nature. Lipophobic is desired for make resins that are at least partially lipid in nature. A hydro-lipophobic coating can be applied using a variety of materials, including, for example, tetramethylsilane, titanium oxide, or using a treatment a fluorine based functional group, such as Perfluorobutanesulfonic acid (such as Scotchgard® from 3M) or a treatment with a perfluoroalkyl group (such as AG-E500D from Mitsubishi®). In some embodiments, a wax coating would also be suitable, however was may be susceptible to wetting by epoxy or some liquid resins.
FIG. 17A-D illustrate coated abrasive articles made with a hydro-lipophobic coating applied to an attachment side of a backing prior to a make coat being applied on an abrasive side of the backing. FIG. 17A illustrates a mesh backing 2100 coated with a make resin 2110. FIG. 17B illustrates a mesh backing 2100 with precision shaped abrasive particles 2120 adhered to a make coat on the mesh backing. FIG. 17C illustrates a mesh backing 2100 with crushed abrasive grains 2130 coated on a make resin. FIG. 17D illustrates a view of the back 2160 of the abrasive article of FIG. 17C. As illustrated, there is substantially no make coat bleeding through onto the attachment side of the backing. Loops 2140 and backside 2150 of mesh are substantially free of make resin.
FIGS. 17E and 17F illustrate a comparative backing coated with a make resin without an applied hydrophobic coating. FIG. 17E illustrates a coated side 2170 and FIG. 17F illustrates a loop side 2180. As illustrated, make resin has permeated through from the coated side 2170 to loop side 2180.
FIG. 18 illustrates a method of making a coated abrasive article. Method 2200 may allow for more efficient and cheaper manufacturing of coated abrasive articles on open substrates, such as an open mesh backing.
In block 2210, a loop side coating is applied to a backing substrate. The loop side coating is a hydrophobic coating 2202, for example, such as tetramethyl silane, titanium oxide, or treatment with a fluorinated compound. Another treatment 2206 may also be applied. For example, a plasma treatment may be used to make a loop-side of a backing hydrophobic. The hydrophobic coating applied in block 2210 may be a temporary coating that dissipates over time or is otherwise removed during use, in one embodiment. In another embodiment, the hydrophobic coating is a layer applied to the backing that is maintained through manufacturing and abrading of a workpiece using the coated abrasive article.
In block 2220, a make coat is applied to the abrasive side of the backing, opposite the hydrophobic coated side of the backing. The make coat may be a resin coating 2212 or a hot melt adhesive coating 2214, as described herein. Applying a make coat may also comprise applying a separate laminate coating layer 2216, as described herein. The laminate layer may be a blown melty film 2218, or another coating layer 2222.
The make coat may be applied using a roll coating method, as illustrated in block 2224, or using a knife coating method, as illustrated in block 2226. Other suitable methods may also be used, as illustrated in block 2228.
The hydrophobic coating on the loop side of the backing prevents the make coat, when applied to the backing, from bleeding through the substrate and onto the loop side. In some embodiments, the loop side of the backing is substantially free of make coat.
In block 2230, abrasive particles are applied to the make layer. The abrasive particles may be shaped abrasive particles 2231, crushed abrasive particles, 2232, agglomerates 2234, or other particles 2236 as described herein. The abrasive particles may embed within the make resin and thus adhere to the backing.
Additional coating layers may also be applied to the adhered particles, including a size coat, a supersize coat, grinding aid or additional functional layers.
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.
Unless specified otherwise herein, 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.
Unless specified otherwise herein, the term “substantially no” as used herein refers to a minority of, or mostly no, as in less than about 10%, 5%, 2%, 1%, 0.5%, 0.01%, 0.001%, or less than about 0.0001% or less.
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 were 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. 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. Further, information that is relevant to a section heading may occur within or outside of that particular section. Furthermore, all publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.
In the methods described herein, the steps can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Furthermore, specified steps can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed step of doing X and a claimed step 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.
Select embodiments of the present disclosure include, but are not limited to, the following: An abrasive article is presented that includes a fabric substrate comprising strands forming first void spaces between the strands, the fabric substrate comprising an abrasive side and an attachment side. The abrasive article also includes a coating on the attachment side, and a make layer joined to the fabric substrate on the abrasive side, and abrasive particles joined to the make layer. The abrasive article also includes a plurality of second void spaces extending through the make layer coinciding with first void spaces in the fabric substrate. The coating on the fabric substrate reduces the surface energy and features both hydrophobic and lipophobic properties. The attachment side of the fabric substrate is substantially free of make layer.
The abrasive article may be implemented such that the coated attachment side includes one part of a two-part hook and loop attachment system.
The abrasive article may be implemented such that the fabric substrate comprises a woven or knitted material.
The abrasive article may be implemented such that the abrasive particles comprise shaped abrasive particles.
The abrasive article may be implemented such that the abrasive particles comprise agglomerate abrasive particles, and wherein the agglomerate abrasive particles comprise shaped abrasive particles.
The abrasive article may be implemented such that the agglomerate abrasive particles are shaped agglomerate abrasive particles, and wherein the shape comprises an nonagon, an octagon, a heptagon, a hexagon, a triangle, a parallelogram, a rhombus, a rectangle, a square, a pentagon, a circle, an oval, a heart, a cross, an arrow, a star, or a crescent.
The abrasive article may be implemented such that the agglomerate abrasive particles are arranged in a pattern on the fabric substrate.
The abrasive article may be implemented such that the agglomerate abrasive particles are arranged randomly on the fabric substrate.
The abrasive article may be implemented such that air flows through the article at a rate of at least 0.5 L/s, such that, when in use, dust can be removed from an abraded surface through the abrasive article.
The abrasive article may be implemented such that the make coat comprises a resin or a hot melt.
The abrasive article may be implemented such that the coating comprises applying a plasma treatment in a hydrophobic and lipophobic atmosphere.
The abrasive article may be implemented such that the plasma treatment comprises a fluorochemical or a silane.
The abrasive article may be implemented such that the coating comprises a hydrophobic and lipophobic chemical.
The abrasive article may be implemented such that the chemical is a fluorinated compound, a silane or a silicone.
The abrasive article may be implemented such that the coating comprises nanoparticles.
The abrasive article may be implemented such that the nanoparticles are silica nanoparticles or carbon nanotubes.
The abrasive article may be implemented such that it includes a size coat.
The abrasive article may be implemented such that it includes a supersize coat.
The abrasive article may be implemented such that the supersize coat is a stearate coating.
A method of making an abrasive article is presented that includes coating an attachment side of a fabric substrate with a hydrophobic coating material, joining a make layer composition to the fabric substrate on an abrasive side of the fabric substrate and joining abrasive particles to the make layer composition. The fabric substrate comprises strands forming first void spaces between the strands.
The method may be implemented such that it also includes curing the curable resin composition to provide a cured resin composition.
The method may be implemented such that it also includes the curing creates a plurality of second void spaces coinciding with first void spaces in the fabric substrate.
The method may be implemented such that the abrasive particles comprise agglomerate abrasive particles, and wherein the agglomerate abrasive particles comprise shaped abrasive particles.
The method may be implemented such that the agglomerate abrasive particles are shaped agglomerate abrasive particles, and wherein the shape comprises an nonagon, an octagon, a heptagon, a hexagon, a triangle, a parallelogram, a rhombus, a rectangle, a square, a pentagon, a circle, an oval, a heart, a cross, an arrow, a star, or a crescent.
The method may be implemented such that joining the abrasive agglomerates to the curable resin composition comprises depositing the abrasive agglomerates in a pattern.
The method may be implemented such that joining the abrasive agglomerates to the curable resin composition comprises depositing the abrasive agglomerates randomly.
The method may be implemented such that the make coat comprises a resin or a hot melt.
The method may be implemented such that the coating comprises a plasma treatment.
The method may be implemented such that the coating comprises a fluorinated compound.
The method may be implemented such that it also includes joining a size layer composition to the abrasive particle layer.
The method may be implemented such that it also includes joining a supersize layer composition to the size layer.
An abrasive article is presented that includes a fabric substrate comprising a plurality of strands forming first void spaces between the strands, an adhesive layer comprising adhesive bonded to the plurality of strands and abrasive particles embedded within the adhesive layer.
The abrasive article may be implemented such that the adhesive layer comprises a heat activated adhesive.
The abrasive article may be implemented such that the abrasive particles are crushed abrasive particles, platey abrasive particles, formed abrasive particles, shaped abrasive particles, or partially shaped abrasive particles.
The abrasive article may be implemented such that the abrasive particles comprise agglomerate abrasive particles, and wherein the agglomerate abrasive particles comprise shaped abrasive particles.
The abrasive article may be implemented such that the agglomerate abrasive particles are shaped agglomerate abrasive particles, and wherein the shape comprises an nonagon, an octagon, a heptagon, a hexagon, a triangle, a parallelogram, a rhombus, a rectangle, a square, a pentagon, a circle, an oval, a heart, a cross, an arrow, a star, or a crescent.
The abrasive article may be implemented such that the abrasive agglomerates are embedded in the adhesive layer in a pattern.
The abrasive article may be implemented such that the abrasive agglomerates are embedded in the adhesive layer randomly.
The abrasive article may be implemented such that the adhesive layer is bonded to the plurality of strands on an adhesive side of the fabric substrate, and wherein, on an attachment side, the fabric substrate is coated with a hydrophobic coating.
The abrasive article may be implemented such that the hydrophobic coating comprises a plasma treatment.
The abrasive article may be implemented such that the hydrophobic coating comprises fluorinated compound.
A method of making an abrasive article is presented that includes applying a hydrophobic coating to an attachment side of a fabric substrate and applying an adhesive layer to an abrasive side of the fabric substrate. The fabric substrate comprises strands forming first void spaces between the strands. The adhesive layer is applied such that adhesive adheres substantially only to the strands and does not substantially extend into the void spaces. The method also includes applying a plurality of abrasive particles to the adhesive layer such that the abrasive particles are partially embedded within the adhesive layer.
The method may be implemented such that the adhesive layer comprises a heat activated adhesive.
The method may be implemented such that applying an adhesive layer comprises laminating the fabric substrate with an adhesive layer.
The method may be implemented such that it also includes heating the adhesive layer.
The method may be implemented such that applying the plurality of abrasive particles comprises drop-coating the abrasive particles.
The method may be implemented such that the abrasive particles are heated.
The method may be implemented such that the adhesive layer is heated.
The method may be implemented such that it also includes applying a size coat.
The method may be implemented such that it also includes applying a supersize coat.
The method may be implemented such that the abrasive particles comprise agglomerate abrasive particles. The agglomerate abrasive particles comprise shaped abrasive particles.
The method may be implemented such that the agglomerate abrasive particles are shaped agglomerate abrasive particles, and wherein the shape comprises an nonagon, an octagon, a heptagon, a hexagon, a triangle, a parallelogram, a rhombus, a rectangle, a square, a pentagon, a circle, an oval, a heart, a cross, an arrow, a star, or a crescent.
The method may be implemented such that applying the abrasive agglomerates to the adhesive layer comprises depositing the abrasive agglomerates in a pattern.
The method may be implemented such that applying the abrasive agglomerates to the adhesive layer comprises depositing the abrasive agglomerates randomly.

Examples

The examples described herein are intended solely to be illustrative, rather than predictive, and variations in the manufacturing and testing procedures can yield different results. All quantitative values in the Examples section are understood to be approximate in view of the commonly known tolerances involved in the procedures used. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom.
Unless stated otherwise, all reagents were obtained or are available from chemical vendors such as Sigma-Aldrich Company, St. Louis, Mo., or may be synthesized by known methods. Unless otherwise reported, all ratios are by dry weight.
Unit Abbreviations used in the Examples: gsm=grams per square meter; cm=centimeter; μm=micron.
Materials used in the Examples are reported in Table 1, below:

TABLE 1

MESH	Net Mesh GR150 H100 (150 gsm) with loops knitted on one
	side available from SitiP, S.p.A., Cene, Italy.
PFR1	Phenol-formaldehyde resin having a phenol to formaldehyde
	molar ratio of 1:1.5-2.1, and catalyzed with 2.5 percent by
	weight potassium hydroxide.
PRR2	Water-based phenol-formaldehyde resin supplied by Georgia-
	Pacific Chemicals LLC, Atlanta, GA, with 75% solid.
CACO	Calcium carbonate commercially available as HUBERCARB
	Q325 from Hubercarb Engineered Materials, Atlanta Georgia.
RED	Red synthetic iron oxide pigment supplied by Venator Americas
	LLC, The Woodlands, TX, under the trademark KROMA ®.
Interwet	Surfactant supplied by Valtris Specialty Chemicals, Walton
	Hills, OH.
SIL	Silicon Dioxide Cabosil M5 from ET HORN CO, La Mirada
	California.
MKR1	Phenolic make resin 1, prepared by mixing 55 parts by weight of
	PFR, 44.5 parts by weight of CACO, and 0.5 parts by weight of
	SIL.
MKR2	Phenolic make resin 2, prepared by mixing 97.2 parts by weight
	of PFR2, 1 parts by weight of water, 1.6 parts by weight of
	RED, and 0.2 parts by weight of Interwet.
MKR3	Phenolic make resin 2, prepared by mixing 50.5 parts by weight
	of PFR2, 40 parts by weight of CACO, 1.6 parts by weight of
	RED, 7.7 parts by weight of water, and 0.2 parts by weight of
	Interwet.
SAP	Shaped abrasive particles, prepared according to the disclosure
	of U.S. Pat. No. 8,142,531 (Adefris et al.). The SAP used in the
	examples were about 200 μm (side length) × 50 μm (thickness),
	with a draft angle approximately 98 degrees.
AOP	Fused and fired Aluminum oxide particles of size P180,
	produced by Triebacher, Austria
SiC	Silicon Carbide abrasive mineral supplied by Jiangsu Leyuan
	New Materials Group Co., Ltd, Lianyungang City, China.
SLU	Slurry, prepared by mixing 39.5 parts by weight of PFR, 0.5
	parts by weight of SIL, 12 parts by weight of SAP, and 48 parts
	by weight of AOP.

A. Plasma-Treatment Examples

A sheet of MESH of about 22.9 cm×22.9 cm were mounted on the powered electrode of Reactor One with the loop side facing up to the chamber atmosphere. The reactor chamber was pumped down to a base pressure of less than 1.3 Pa (10 mTorr). Then tetramethylsilane (TMS, available as a liquid from Aldrich Chemical Company, Milwaukee, Wis.) was introduced into the chamber at a flow rate of 25 standard cubic centimeters per minute (sccm). When the TMS flow was established, oxygen (O₂, available in gas cylinders from Oxygen Service Company, Minneapolis, Minn.) was metered into the chamber at a flow rate of 500 sccm. The total chamber pressure was 23.9 Pa (180 mTorr). Then, a plasma was ignited with radio frequency (RF) power of 450 watts. An ion sheath formed around the powered electrode, extended approximately 10-15 mm outward and thus encompassed the porous article. Plasma treatment was continued for two minutes. After extinguishing the plasma, the gas flows were stopped, the chamber pressure brought down to below 10 mTorr, after which the chamber was vented to atmosphere. Details related to plasma processing and operation can be found in U.S. Pat. No. 6,878,419 (David et al.) Multiple sheets were treated by repeating this process.
The first abrasive example was prepared with abrasive particles only coated on the raised yarns of the coat side of the plasma-treated MESH: MKR was roll coated on the coat side of a treated MESH as mentioned above with about 76 μm controlled gap, and followed by drop coat of 4 grams of SAP on the top of MKR. Then the abrasive sample was put in oven for resin cure.
The second abrasive example was prepared with pattern-coated abrasive slurry on the coat side of the plasma-treated MESH: a 0.15 mm thick hexagon-patterned stencil, which has staggered hexagons as open areas with 2 mm of side and adjacent distance, was put on the top of the coat side of a treated MESH as mentioned above. All the edges were taped tightly to the MESH to ensure there was no space between the stencil and mesh web. Then SLU was coated through the stencil using a rubber squeegee. The stencil was removed after coating, and the abrasive sample was put in oven for resin cure.
Creating Hydrophobicity on Loop Side with Hydrophobic Coating
A composition comprising 0.2 g AG-E500D (ASAHI GUARD E-SERIES AG-E500D, 30%, from AGC Chemicals Americas Inc. Exton, Pa.), 1.0 g sodium carboxymethyl cellulose (CMC, average Mw 90K, Sigma-Aldrich Company), 20.0 g hexanes (98.5% from Sigma-Aldrich Company), and 78.0 g water was blended with a high speed shearer (IKA EUROSTAR 200 Overhead Stirrer, IKA Works, Inc. Wilmington, N.C.) at a speed of 1500 rpm for 20 min to form a temporary stable foam solution.
The foam solution was applied onto the loop side of the MESH backing with a knife coater with the add-on of 11.8 g on 250 square centimeters area. The sample was dried at 80 C for 5 minutes and then cured at 105 C for 1 minute. Optionally, the treated MESH backing was rinsed with 60 C water and then dried at 105 C for 1 minute.

Making Coated MESH Abrasive Articles Comprising SAP

MKR2 was applied to the non-loop side of the treated MESH backing with knife coating. Pressurized air was then applied from the loop side to open the pores on the MESH backing. P150 grade SAP was drop coated onto the make resin and then the sample was dried at 90 C for 60 minutes.
MKR2 on treated MESH backing is illustrated in FIG. 17A.
P150 SAP coated on MESH backing is illustrated in FIG. 17B.

Making Coated MESH Abrasive Articles Comprising SiC

The same procedure was used except that MR3 and P220 grade SiC was used. P220 grade SiC coated on the MESH backing is illustrated in FIG. 17C, with a backside illustrated in FIG. 17D.

COMPARATIVE EXAMPLE

For comparative purposes, on a piece of MESH backing with the size of 23×28 cm, half of the MESH backing was treated with hydrophobic coating and half of the backing remain untreated. MKR2 was applied onto the non-loop side of the backing with knife coater. Due to the repellent property of the treated loop side, the make resin can only sit on the non-loop side of the MESH backing. On the untreated MESH backing, the make resin wicked through the MESH backing and contaminated the loop side of the MESH backing. The result is illustrated in FIG. 19 .

Claims

1. An abrasive article comprising:

a fabric substrate comprising strands forming first void spaces between the strands, the fabric substrate comprising an abrasive side and an attachment side;

a coating on the attachment side;

a make layer joined to the fabric substrate on the abrasive side;

abrasive particles joined to the make layer;

a plurality of second void spaces extending through the make layer coinciding with first void spaces in the fabric substrate; and

wherein the coating on the fabric substrate reduces the surface energy and features both hydrophobic and lipophobic properties, and wherein the attachment side of the fabric substrate is substantially free of make layer.

2. The abrasive article of claim 1, wherein the coated attachment side includes one part of a two-part hook and loop attachment system.

3. The abrasive article of claim 1, wherein the fabric substrate comprises a woven or knitted material.

4. The abrasive article of claim 1, wherein the abrasive particles comprise shaped abrasive particles.

5-7. (canceled)

8. The abrasive article of claim 1, wherein the make coat comprises a resin or a hot melt.

9. The abrasive article of claim 1, wherein the coating comprises applying a plasma treatment in a hydrophobic and lipophobic atmosphere.

10. (canceled)

11. The abrasive article of claim 1, wherein the coating comprises a hydrophobic and lipophobic chemical.

12. The abrasive article of claim 1, wherein the chemical is a fluorinated compound, a silane or a silicone.

13. The abrasive article of claim 1, wherein the coating comprises nanoparticles.

14-17. (canceled)

18. A method of making an abrasive article comprising:

coating an attachment side of a fabric substrate with a hydrophobic coating material;

joining a make layer composition to the fabric substrate on an abrasive side of the fabric substrate; and

joining abrasive particles to the make layer composition;

wherein the fabric substrate comprises strands forming first void spaces between the strands.

19. The method of claim 18, and further comprising curing the curable resin composition to provide a cured resin composition and, wherein the curing creates a plurality of second void spaces coinciding with first void spaces in the fabric substrate.

20-23. (canceled)

24. The method of claim 18, wherein the make coat comprises a resin or a hot melt.

25. The method of claim 18, wherein the coating comprises a plasma treatment.

26. The method of claim 18, wherein the coating comprises a fluorinated compound.

27. (canceled)

28. An abrasive article comprising:

a fabric substrate comprising a plurality of strands forming first void spaces between the strands;

an adhesive layer comprising adhesive bonded to the plurality of strands; and

abrasive particles embedded within the adhesive layer.

29. The abrasive article of claim 28, wherein the adhesive layer comprises a heat activated adhesive.

30. The abrasive article of claim 28, wherein the abrasive particles comprise agglomerate abrasive particles, and wherein the agglomerate abrasive particles comprise shaped abrasive particles.

31. The abrasive article of claim 28, wherein the adhesive layer is bonded to the plurality of strands on an adhesive side of the fabric substrate, and wherein, on an attachment side, the fabric substrate is coated with a hydrophobic coating.

32. The abrasive article of claim 31, wherein the hydrophobic coating comprises a plasma treatment.

33. The abrasive article of claim 31, wherein the hydrophobic coating comprises fluorinated compound.

34-40. (canceled)