CN114555296A

CN114555296A - Coated abrasive article and method of making same

Info

Publication number: CN114555296A
Application number: CN202080071950.7A
Authority: CN
Inventors: 刘玉阳; 安·M·霍金斯; 杰弗里·I·威尔逊; 布赖恩·G·克特; 欧内斯特·L·瑟伯; 尼格斯·B·艾德弗里斯; 李军廷; 费伊·T·萨蒙
Original assignee: 3M Innovative Properties Co
Current assignee: 3M Innovative Properties Co
Priority date: 2019-10-17
Filing date: 2020-10-09
Publication date: 2022-05-27
Also published as: WO2021074756A1; US20220339761A1; EP4045230B1; EP4045230A1

Abstract

A method of making a coated abrasive article, the method comprising: depositing a precisely shaped abrasive sheet into a precisely shaped cavity in a production tool; depositing diluted abrasive particles onto the production tool; contacting the precisely shaped abrasive flakes and the diluted abrasive particles with a curable make layer precursor disposed on a major surface of a backing; separating the tool from the precisely shaped abrasive sheet and the diluted abrasive particles; and at least partially curing the curable make layer precursor to provide an at least partially cured make layer precursor. Coated abrasive articles that can be made by the method are also disclosed.

Description

Coated abrasive article and method of making same

Technical Field

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

Background

Coated abrasive articles include abrasive particles adhered to a backing by a material comprising a first crosslinked polymeric resin, commonly referred to as a make coat or make coat. In most cases, a second cross-linked polymer resin (often referred to as a size coat or size coat) is disposed over the make coat and abrasive particles. Optionally, a third layer (referred to as a supersize layer or supersize) is disposed on the size layer. The supersize, if present, typically comprises a grinding aid and/or an anti-loading component.

In recent years, there has been a trend to use shaped abrasive particles (e.g., triangular flakes), and attempts have been made to position the particles in various desired orientations relative to the backing. However, in many cases, the shaped abrasive particles are substantially tilted from their original orientation prior to curing of the make layer precursor resin that forms the make layer.

Disclosure of Invention

It would be desirable to have methods of making coated abrasive articles in which the abrasive particles substantially retain their original orientation, and coated abrasive articles that can be made by these methods. Advantageously, the present disclosure provides a practical solution to both of these problems.

In one aspect, the present disclosure provides a method of making a coated abrasive article, the method comprising the sequential steps of:

a) providing a production tool comprising a carrier member having a dispensing surface, the production tool having precisely shaped cavities extending into the carrier member from cavity openings at the dispensing surface;

b) depositing precisely-shaped abrasive flakes into at least some of the precisely-shaped cavities;

c) depositing diluted abrasive particles on the dispensing surface;

d) contacting the precisely shaped abrasive flakes and the diluted abrasive particles with a curable make layer precursor disposed on a major surface of a backing;

e) optionally separating the tool from the precisely shaped abrasive sheet and the diluted abrasive particles; and

f) at least partially curing the curable make layer precursor to provide an at least partially cured make layer precursor.

In some preferred embodiments, the sequential steps further comprise:

g) disposing a curable size coat precursor onto the at least partially cured make coat precursor, the precisely shaped abrasive flakes, and the diluted abrasive particles; and

h) at least partially curing the curable size layer precursor.

In another aspect, the present disclosure provides a coated abrasive article made according to the foregoing method.

In another aspect, the present disclosure provides a coated abrasive article comprising:

a backing having a first major surface;

a make layer disposed on and secured to the backing;

an abrasive layer in contact with and secured to the make coat, wherein the abrasive layer comprises a precisely shaped abrasive sheet and diluted abrasive particles, wherein the precisely shaped abrasive sheet comprises a second major surface disposed at a dihedral angle less than or equal to 60 degrees relative to the first major surface of the backing, and wherein at least a majority of the precisely shaped abrasive sheet each overhangs a respective plurality of the diluted abrasive particles; and

and the compound glue layer is arranged on the bottom glue layer and the abrasive layer.

In yet another aspect, the present disclosure provides a coated abrasive article comprising:

a backing having a major surface;

a make layer disposed on and secured to the backing;

an abrasive layer in contact with and secured to the make coat, wherein the abrasive layer comprises islands, each island comprising at least one precisely shaped sheet of abrasive material and diluted abrasive particles, and wherein the islands are separated from each other; and

As used herein:

the term "generally aligned with a longitudinal axis" when used with respect to a precisely shaped sheet of abrasive material means that the longitudinal axis of each precisely shaped abrasive particle is similarly or identically aligned with respect to the longitudinal axis of a coated abrasive article (e.g., coated abrasive tape).

The term "generally aligned with the axis of rotation" when used with respect to a precisely shaped abrasive sheet means that the longitudinal axis of each precisely shaped abrasive particle is similarly or identically aligned with respect to the axis of rotation of the coated abrasive article (e.g., coated abrasive disk).

The term "closed abrasive coating" means that the abrasive layer is closely packed with substantially no space between adjacent abrasive particles of sufficient size to deposit another abrasive particle of comparable size.

The term "open abrasive coating" means not a closed abrasive coating. The open coating may be characterized by regions having few, if any, abrasive particles.

The term "precisely shaped abrasive particles" refers to abrasive particles that are substantially in the shape of the cavity portion of a mold or production tool, wherein the particle precursors are dried prior to optional calcination and then sintering.

As used herein with respect to precisely shaped abrasive particles and cavities, the term "length" refers to the largest dimension of the abrasive particle or cavity. "width" refers to the largest dimension of the abrasive particle perpendicular to the length. The term "thickness" or "height" refers to the dimension of the precisely shaped abrasive particles or cavities perpendicular to the length and width.

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

Drawings

Fig. 1 is a schematic process flow diagram of an exemplary process 100 according to the present disclosure.

Fig. 2 is a schematic process flow diagram of an exemplary process 200 according to the present disclosure.

Fig. 3 is a schematic process flow diagram of an exemplary process 300 according to the present disclosure.

Fig. 4 is a schematic process flow diagram of an exemplary process 400 according to the present disclosure.

Fig. 5 is a schematic process flow diagram of an exemplary process 500 according to the present disclosure.

Fig. 6 is a schematic side view of an exemplary coated abrasive article 600 according to the present disclosure.

Fig. 7A is a schematic side view of an exemplary coated abrasive article 700 according to the present disclosure.

Fig. 7B is a schematic top view of an exemplary coated abrasive article 700 according to the present disclosure.

Fig. 8 is a schematic top view of an exemplary coated abrasive disc 800 according to the present disclosure.

Fig. 9A and 9B are optical micrographs of the coated abrasive article prepared in example 1.

Fig. 10A and 10B are optical micrographs of the coated abrasive article prepared in comparative example a.

Fig. 11A and 11B are optical micrographs of the coated abrasive article prepared in example 2.

Fig. 12A and 12B are optical micrographs of the coated abrasive article prepared in comparative example B.

Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure. The figures may not be drawn to scale.

Detailed Description

Referring now to fig. 1, an exemplary method 100 of making a coated abrasive article according to the present disclosure provides a production tool 110 including a carrier member 115 and a dispensing surface 112. A precisely shaped cavity 120 extends from the cavity opening 114 at the dispensing surface 112 and into the carrier member 115. Such tools are well known and used to produce coated abrasive articles and typically take the form of metal rolls, polymeric sheets, polymeric roll sleeves or polymeric tapes.

Next, the precisely shaped abrasive sheets 130 are positioned within the precisely shaped cavities 120 so that they are oriented. The diluted abrasive particles 140 are then disposed on the distribution surface 112 of the production tool 110.

The abrasive particle-laden dispensing surface 112 of the production tool 110 is then brought into contact with a make layer precursor 150 disposed on a backing 160. The make layer precursor 150 is sufficiently adherent that separation of the backing and make layer precursor combination from the dispensing surface 112 transfers the precisely shaped abrasive flakes 130 and the diluted abrasive particles 140 from the production tool 110 to the make layer precursor 150. The make layer precursor is then cured (not shown) and the size layer precursor is applied and cured to provide a coated abrasive article (not shown).

In a variation of method 100, an exemplary method 200 (see fig. 2) of making a coated abrasive article according to the present disclosure provides a production tool 210 including a carrier member 205 and a dispensing surface 212. The precisely shaped cavities 220 extend from the cavity openings 214 at the dispensing surface 212 and extend into the carrier member 205 in an inclined manner.

Next, precisely shaped abrasive sheets 230 are positioned within the precisely shaped cavities 220 such that they are oriented, in some preferred embodiments in an oblique manner. The diluted abrasive particles 240 are then disposed on the dispensing surface 212 of the production tool 210 such that some of the diluted abrasive particles become lodged within the precisely shaped cavities and accumulate on top of the dispensing surface.

The abrasive particle-laden dispensing surface 212 of the production tool 210 is then brought into contact with the make layer precursor 250 disposed on the backing 260. The make layer precursor 250 is sufficiently adherent that optional separation of the backing and make layer precursor combination from the dispensing surface 212 transfers the precisely shaped abrasive flakes 230 and the diluted abrasive particles 240 from the production tool 210 to the make layer precursor 250. The make layer precursor is then cured (not shown) and the size layer precursor is applied and cured to provide a coated abrasive article (not shown).

Variations in cavity and particle size and shape can lead to many related processes.

For example, referring now to fig. 3, an exemplary method 300 of making a coated abrasive article according to the present disclosure, similar to

processes

100 and 200, provides a production tool 310. The precisely shaped cavity 320 has a cavity opening 314. A precisely shaped sheet of abrasive 330 is disposed within the precisely shaped cavities 320. The diluted abrasive particles 340 are then placed in the cavities alongside the precisely shaped sheet of abrasive 330. After transfer to the make layer precursor 350, the precisely shaped abrasive flakes 330 and the diluted abrasive particles 340 are positioned adjacent to each other. The make layer precursor is then cured (not shown) and the size layer precursor is applied and cured to provide a coated abrasive article (not shown).

Referring now to fig. 4, an exemplary method 400 of making a coated abrasive article according to the present disclosure, similar to

processes

100 and 200, provides a production tool 410. The precisely shaped cavity 420 has a cavity opening 414. Precisely shaped abrasive sheets 430 are disposed within the precisely shaped cavities 420 to aid in their vertical orientation. The diluted abrasive particles 440 are then placed in the cavities alongside the precisely shaped abrasive sheet 430. After transfer to the make layer precursor 450, the precisely shaped abrasive flakes 430 and the diluted abrasive particles 440 are positioned adjacent to each other. The make layer precursor is then cured (not shown) and the size layer precursor is applied and cured to provide a coated abrasive article (not shown).

Referring now to fig. 5, an exemplary method 500 of making a coated abrasive article according to the present disclosure, similar to

processes

100 and 200, provides a production tool 510. The precisely shaped cavity 520 has a cavity opening 514. Precisely shaped abrasive sheets 530 are disposed within the precisely shaped cavities 520 to help them orient vertically. The diluted abrasive particles 540 are then placed in the cavities alongside precisely shaped abrasive sheets 530. After transfer to the make layer precursor 550, the precisely-shaped abrasive flakes 530 and the diluted abrasive particles 540 are disposed adjacent to one another. The make layer precursor is then cured (not shown) and the size layer precursor is applied and cured to provide a coated abrasive article (not shown).

Useful production tools and methods for their preparation are well known in the art and have been practiced. Typically, the openings of the precisely shaped cavities are arranged in a rectangular or rotationally symmetric array, but this is not essential. For example, the cavity may be shaped as a regular rectangular pyramid, a regular truncated pyramid, a cone or a truncated cone cavity.

Typically, the opening of the cavity at the dispensing surface is rectangular; however, this is not essential. The length, width and depth of the cavities in the carrier member will generally be determined at least in part by the shape and size of the abrasive particles with which they are used. For example, if the precisely shaped abrasive sheet is shaped as an equilateral triangular sheet, the length of each cavity is preferably 1.1 to 1.2 times the maximum length of the edge of the precisely shaped abrasive sheet, the width of each cavity is preferably 1.1 to 2.5 times the thickness of the precisely shaped abrasive sheet, and if the precisely shaped abrasive sheet is fully contained within the cavity, the corresponding depth of the cavity should preferably be 1.0 to 1.2 times the width of the precisely shaped abrasive sheet, and if not fully contained within the cavity, the corresponding depth of the cavity should be smaller. Also, larger sizes may be useful if it is desired to fill the cavity with precisely shaped abrasive flakes and diluted abrasive particles, and will be apparent to those skilled in the art.

Alternatively, for example, if the precisely shaped abrasive sheet is shaped as a triangular or rectangular sheet, the length of each cavity may preferably be less than the length of the edge of the precisely shaped abrasive sheet, and/or if the precisely shaped abrasive sheet is to protrude from the cavity, the respective depth of the cavity should be less than the width of the abrasive particles. Similarly, the width of the cavities should be selected such that a single abrasive particle fits within each cavity. Similarly, the width of the cavities should be selected such that at least a single precisely shaped abrasive particle fits within each cavity. The cavity openings may be angled and offset from adjacent openings.

The carrier member may be in the form of an endless belt, a sheet, a continuous sheet or web, a coating roll, a sleeve mounted on a coating roll, or a die. If the production tool is in the form of a belt, sheet, web or sleeve, it will have a contact surface and a non-contact surface. If the production tool is in the form of a roll, it will only have a contact surface.

The support member may be prepared, for example, according to the following procedure. A master tool is first provided. The master tool is typically made of or plated with a metal such as nickel. The master tool can be made by any conventional technique, such as, for example, engraving, hobbing, knurling, electroforming, diamond turning, or laser machining. If a pattern on the surface of the production tool is desired, the master tool should have a pattern that is the inverse of the pattern on the surface of the production tool. The thermoplastic material can be embossed with a master tool to form a pattern. The embossing may be performed with the thermoplastic material in a flowable state. After embossing, the thermoplastic material may be cooled to cause solidification.

The carrier member may also be formed by embossing a pattern into a heat-softened shaped polymer film. In this case, the film thickness may be less than the cavity depth. This is advantageous for improving the flexibility of the carrier with deep cavities.

Preferably, the support member comprises a metal and/or an organic polymer. Such organic polymers are preferably moldable, have low cost, and are reasonably durable when used in the abrasive particle deposition process of the present disclosure. Examples of organic polymers suitable for making the carrier member may be thermosets and/or thermoplastics, including: polypropylene, polyethylene, vulcanized rubber, polycarbonate, polyamide, Acrylonitrile Butadiene Styrene (ABS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyimide, Polyetheretherketone (PEEK), Polyetherketone (PEK), as well as polyoxymethylene plastics (POM, acetal), poly (ethersulfone), poly (methyl methacrylate), polyurethane, polyvinyl chloride, and combinations thereof.

The carrier member may also be prepared from a cured thermosetting resin. A production tool made of a thermosetting material can be prepared according to the following procedure. Uncured thermosetting resin is applied to a master tool of the type described above. When the uncured resin is on the surface of the master tool, the uncured resin can be cured or polymerized by heating so that it solidifies to have the inverse shape of the pattern of the surface of the master tool. The cured thermosetting resin is then removed from the surface of the master tool. The production tool may be prepared from a cured radiation curable resin, such as, for example, an acrylated urethane oligomer. Radiation-cured production tools are prepared in the same manner as production tools prepared from thermosetting resins, except that curing is performed by exposure to radiation (e.g., ultraviolet radiation).

The carrier member may have any thickness as long as it has sufficient depth to contain the abrasive particles and sufficient flexibility and durability to be used in the manufacturing process. If the carrier member comprises an endless belt, a carrier member having a thickness of about 0.5 to about 10 millimeters may generally be employed; however, this is not essential.

The resiliently compressible layer may be secured to the non-dispensing surface of the carrier member regardless of whether the cavity extends through to the back surface. This may facilitate web handling and/or removal of abrasive particles from the cavities. For example, in embodiments where the resiliently compressible layer includes a shaped recess aligned with the respective second opening of each of at least a portion of the cavities, the abrasive particles extending into the cavities in the shaped recesses can be mechanically urged out of the cavities by pressure applied against the resiliently compressible layer. This may occur, for example, by compression at a nip roll, where the abrasive particle positioning system contacts the make coat precursor on the backing during the manufacture of the coated abrasive article. The resiliently compressible layer, if present, can have any thickness, with the particular choice of abrasive particles and equipment conditions determining the choice of thickness, composition, and/or hardness. If the resiliently compressible layer comprises an endless belt, a resiliently compressible layer having a thickness of about 1mm to about 25 mm may typically be employed, but this is not required.

Exemplary materials suitable for the resilient compressible layer include resilient foams (e.g., polyurethane foams), rubbers, silicones, and combinations thereof.

The pattern of the contact surface of the production tool is generally characterized by a plurality of cavities or depressions. The openings of the cavities may have any regular or irregular shape, such as, for example, rectangular, semicircular, circular, triangular, square, hexagonal, or octagonal.

The walls of the cavity may be vertical or tapered. The pattern formed by the cavities may be arranged according to a predetermined plan or may be randomly arranged. In some embodiments, the cavities may abut one another. In other embodiments, the lumens may be separated from each other by a distance (e.g., at least 0.1mm, at least 0.2mm, at least 0.3mm, at least 0.4mm, at least 0.5mm, at least 1mm, at least 2mm, at least 3mm, at least 4mm, or even at least 5 mm).

Preferably, the orientation and any inclination of the cavities will be selected such that the finished coated abrasive will align the precisely shaped abrasive sheet such that the abrading performance will be significantly optimized in its intended use.

More details on the manufacture of useful production tools can be found in, for example, U.S. Pat. No. 9,776,302B2 (Keipirt), U.S. patent application publication No. 2016/0311084A1(Culler et Al), and PCT patent publication Nos. WO 2019/102331(Hanschen et Al), WO 2019/102332 Al (Hanschen et Al), WO 2019/102330A 1(Hanschen et Al), WO 2019/102329 Al (Hanschen et Al), and WO 2019/102325A 1(Hanschen et Al).

Abrasive particles (e.g., precisely shaped abrasive flakes and diluted abrasive particles) have sufficient hardness and surface roughness to act as abrasive particles during the abrading process.

The abrasive particles may include organic and/or inorganic particles.

Examples of suitable inorganic abrasive particles include: a molten alumina; heat treated alumina; white fused alumina; CERAMIC alumina materials such as those commercially available under the trade designation 3M CERAMIC ABRASIVE GRAIN from 3M Company (3M Company, st. paul, MN), st paul, MN; brown aluminum oxide; blue alumina; silicon carbide (including green silicon carbide); titanium diboride; boron carbide; tungsten carbide; garnet; titanium carbide; diamond; cubic boron nitride; a garnet; fused alumina-zirconia; iron oxide; chromium oxide; zirconium oxide; titanium dioxide; tin oxide; quartz; feldspar; flint; emery; sol-gel derived abrasive particles (e.g., including both precisely shaped and crushed forms); and combinations thereof.

Preferably, the abrasive particles (particularly precisely shaped abrasive flakes) comprise sol-gel derived α -alumina particles.

Abrasive particles composed of crystallites of alpha alumina, magnesium aluminate spinel, and rare earth hexagonal aluminate can be prepared using sol-gel precursor alpha alumina particles according to the methods described in, for example, U.S. patent No. 5,213,591(Celikkaya et al) and U.S. published patent application nos. 2009/0165394a1(Culler et al) and 2009/0169816a1(Erickson et al).

Precisely shaped abrasive particles based on alpha-alumina can be prepared according to well known multi-step methods. Briefly, the method comprises the steps of: preparing a seeded or unseeded sol-gel alpha-alumina precursor dispersion that can be converted to alpha-alumina; filling one or more mold cavities having a desired profile of precisely shaped abrasive particles with a sol-gel, drying the sol-gel to form precisely shaped ceramic abrasive particle precursors; removing the precisely shaped ceramic abrasive particle precursor from the mold cavity; the method includes calcining a precursor precisely shaped ceramic abrasive particle to form a calcined precursor precisely shaped ceramic abrasive particle, and then sintering the calcined precursor precisely shaped ceramic abrasive particle to form the precisely shaped ceramic abrasive particle. Additional details regarding the process of making sol-gel derived abrasive particles can be found, for example, in U.S. Pat. Nos. 4,314,827(Leitheiser), 5,152,917(Pieper et Al), 5,435,816(Spurgeon et Al), 5,672,097(Hoopman et Al), 5,946,991(Hoopman et Al), 5,975,987(Hoopman et Al), and 6,129,540(Hoopman et Al), as well as in U.S. published patent application No. 2009/0165394Al (Culler et Al). Additional examples of sol-gel derived precisely shaped alpha-alumina (i.e., ceramic) abrasive particles can be found in U.S. Pat. Nos. 5,201,916(Berg), 5,366,523(Rowenhorst (Re 35,570)), 5,984,988(Berg), 8,142,531(Adefris et al), 8,142,891(Culler et al) and 8,142,532(Erickson et al), and U.S. patent application publication Nos. 2012/0227333(Adefris et al), 2013/0040537(Schwabel et al) and 2013/0125477 (Adefris).

In some embodiments, the bottom and top of the precisely shaped abrasive particles are substantially parallel, resulting in a prismatic or truncated pyramidal shape, but this is not required. In some embodiments, the sides of the truncated trigonal pyramid are of equal size and form a dihedral angle of about 82 degrees with the base. However, it should be understood that other dihedral angles (including 90 degrees) may be used. For example, the dihedral angle between the base and each of the sides may independently be in the range of 45 to 90 degrees, typically 70 to 90 degrees, more typically 75 to 85 degrees.

Suitable organic abrasive particles (particularly as dilute abrasive articles) may be formed from thermoplastic polymers and/or thermoset polymers. The organic abrasive particles may be formed from thermoplastic materials such as polycarbonates, polyetherimides, polyesters, polyvinyl chloride (PVC), polymethacrylates, polymethylmethacrylate, polyethylene, polysulfone, polystyrene, acrylonitrile-butadiene-styrene block copolymer, polypropylene, acetal polycondensates, polyurethanes, polyamides, and combinations thereof. The organic abrasive particles may be a mixture of thermoplastic and thermoset polymers. Other suitable organic abrasive particles include natural products such as nutshells.

It is also contemplated that the abrasive particles may comprise abrasive agglomerates, such as, for example, those described in U.S. Pat. Nos. 4,652,275(Bloecher et al), 4,799,939(Bloecher et al), 6,521,004(Culler et al), or 6,881,483(McArdle et al). It is also contemplated that the abrasive particles may comprise precisely shaped polymeric particles comprising an organic binder and optionally abrasive particles such as those described in US 5,714,259(Holmes et al). Additional examples include shaped abrasive composites of abrasive particles in a binder matrix, such as those described in U.S. Pat. No. 5,152,917(Pieper et al). Many such abrasive particles, agglomerates, and composites are known in the art.

In some embodiments, the abrasive particles may be surface treated with a coupling agent (e.g., an organosilane coupling agent) or subjected to other physical treatments (e.g., iron oxide or titanium oxide) to enhance adhesion of the abrasive particles to the binder. The abrasive particles may be treated prior to their combination with the binder, or they may be surface treated in situ by including a coupling agent into the binder.

In some embodiments, the abrasive particles have a mohs hardness of at least 4, at least 5, at least 6, at least 7, or even at least 8.

In some preferred embodiments, the abrasive particles comprise shaped ceramic abrasive particles (e.g., shaped sol-gel derived polycrystalline alpha-alumina particles) that are generally triangular in shape (e.g., triangular prisms or truncated three-sided pyramids).

The length of the abrasive particles is typically selected to be in the range of 1 micron to 4 millimeters, more typically 10 microns to about 3 millimeters, and still more typically 150 microns to 2600 microns, although other lengths may also be used.

The width of the abrasive particles is typically selected to be in the range of 0.1 microns to 3500 microns, more typically 100 microns to 3000 microns, and more typically 100 microns to 2600 microns, although other lengths may also be used.

The thickness of the abrasive particles is typically selected to be in the range of 0.1 to 1600 microns, more typically 1 to 1200 microns, although other thicknesses may also be used.

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

Surface coatings on abrasive particles can be used to improve adhesion between the shaped ceramic abrasive particles and a binder in a coated abrasive article, or can be used to aid in electrostatic deposition of the shaped ceramic abrasive particles. In one embodiment, the surface coating described in U.S. Pat. No. 5,352,254(Celikkaya) may be used in an amount of 0.1% to 2% of the surface coating relative to the weight of the abrasive particles. Such surface coatings are described in U.S. Pat. Nos. 5,213,591(Celikkaya et al), 5,011,508(Wald et al), 1,910,444(Nicholson), 3,041,156(Rowse et al), 5,009,675(Kunz et al), 5,085,671(Martin et al), 4,997,461(Markhoff-Matheny et al) and 5,042,991(Kunz et al). In addition, the surface coating may prevent plugging of the shaped abrasive particles. The term "plugging" is used to describe the phenomenon in which metal particles from the workpiece being abraded are welded to the tops of the shaped ceramic abrasive particles. Surface coatings that perform the above functions are known to those skilled in the art.

The abrasive particles can be independently sized according to a specified nominal grade recognized by the abrasives industry. Exemplary abrasive industry recognized grading standards include those promulgated by ANSI (american national standards institute), FEPA (european producers of abrasives alliance), and JIS (japanese industrial standards). ANSI grade designations (i.e., specified nominal grades) include, for example: ANSI 4, ANSI 6, ANSI 8, ANSI 16, ANSI 24, ANSI 36, ANSI 46, ANSI 54, ANSI 60, ANSI 70, ANSI 80, ANSI 90, ANSI 100, ANSI 120, ANSI 150, ANSI 180, ANSI 220, ANSI 240, ANSI 280, ANSI 320, ANSI 360, ANSI 400, and ANSI 600. FEPA grade designations include F4, F5, F6, F7, F8, F10, F12, F14, F16, F16, F20, F22, F24, F30, F36, F40, F46, F54, F60, F70, F80, F90, F100, F120, F150, F180, F220, F230, F240, F280, F320, F360, F400, F500, F600, F800, F1000, F1200, F1500, and F2000. JIS grade designations include: JIS8, JIS12, JIS16, JIS24, JIS36, JIS46, JIS54, JIS60, JIS80, JIS100, JIS150, JIS180, JIS220, JIS240, JIS280, JIS320, JIS360, JIS400, JIS600, JIS800, JIS1000, JIS1500, JIS2500, JIS4000, JIS6000, JIS8000 and JIS10,000.

According to embodiments of the present disclosure, the average diameter of the abrasive particles may be in a range of 260 microns to 4000 microns according to FEPA grades F60 to F24.

Alternatively, the abrasive particles may be graded to a nominal screening grade using a U.S. Standard Test Sieve conforming to ASTM E11-17, "Steel Wire mesh Test Woven screen Cloth and Test Sieves (Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves)". ASTM E11-17 specifies the design and construction requirements for a test screen that uses a medium of wire mesh woven screen cloth mounted in a frame to sort materials by a specified particle size. A representative designation may be represented as-18 +20, which means that the abrasive particles pass through a test sieve meeting ASTM E11-17 specification for 18 mesh screens and remain on a test sieve meeting ASTM E11-17 specification for 20 mesh screens. In one embodiment, the shaped abrasive particles have a particle size of: so that a majority of the particles pass through the 18 mesh test sieve and may be retained on the 20, 25, 30, 35, 40, 45 or 50 mesh test sieve. In various embodiments, the abrasive particles may have the following nominal sieve grades: -18+20, -20/+25, -25+30, -30+35, -35+40, 5-40+45, -45+50, -50+60, -60+70, -70/+80, -80+100, -100+120, -120+140, -140+170, -170+200, -200+230, -230+270, -270+325, -325+400, -400+450, -450+500, or-500 + 635. Alternatively, a custom mesh size such as-90 +100 may be used.

The precisely shaped abrasive particles can be deposited into the cavities by any suitable method, including, for example, dropping and/or wiping, preferably with vibration or air assistance of the production tool. Typically, an excess of precisely shaped abrasive particles is deposited onto the dispensing surface by an abrasive particle feeder, such that there are more precisely shaped abrasive particles per unit length of the production tool cavity. Providing an excess of precisely shaped abrasive particles helps to ensure that substantially all of the cavities within the production tool are eventually filled with precisely shaped abrasive particles. Since the support area and spacing of precisely shaped abrasive particles is typically designed into the production tool for a particular grinding application, it is desirable not to create too many unfilled cavities. Abrasive particle feeders typically have the same width as the production tool (especially if the production tool includes a roller, sleeve, or endless belt) and supply precisely shaped abrasive particles across the width of the production tool. The abrasive particle feeder may be, for example, a vibratory feeder, a hopper, a chute, a silo, a drip coater, or a screw feeder.

Optionally, a fill assist member is provided after the abrasive particle feeder to move the precisely shaped abrasive particles back and forth over the surface of the production tool and to help orient or slide the precisely shaped abrasive particles into the cavities. The filling aid member may be, for example, a doctor blade, a felt wiper, a brush with a plurality of bristles, a vibrating system, a blower or air knife, a vacuum box, or a combination thereof. The fill assist member moves, translates, aspirates, or shakes the precisely shaped abrasive particles over the dispensing surface to place more of the precisely shaped abrasive particles into the cavities. Without the filling aid member, at least some of the precisely shaped abrasive particles that would normally fall onto the dispensing surface would fall directly into the cavity and need no further movement, but other abrasive particles would then require some additional movement to enter the cavity.

Optionally, the filling aid member may be oscillated laterally in a direction transverse to the longitudinal direction, or otherwise subjected to relative motion, such as circular or elliptical motion relative to the surface of the production tool using a suitable driving force, to help completely fill each cavity in the production tool with abrasive particles. Generally, if a brush is used as the filling aid, the bristles can cover a portion of the dispensing surface, cover a length of 2-4 inches (5.0-10.2 cm) in the longitudinal direction, preferably cover all or almost all of the width of the dispensing surface, and rest gently on or directly above the dispensing surface with moderate flexibility. Vacuum boxes, if used as a fill assist member, are typically used in conjunction with production tools having cavities that extend completely through the production tool; however, even a production tool with a solid back surface may be advantageous as it will flatten the production tool and pull it flatter to improve filling of the cavity.

If the production tool is an endless belt, the belt has a positive slope to advance to a higher elevation as it moves through the abrasive particle feeder. If the production tool is a roller, the abrasive particle feeder may be positioned such that it applies abrasive particles to the roller before the top dead center of the outer circumference of the roller, such as between 270 and 350 degrees on the face of the roller, with the top dead center when traveling clockwise around the roller being 0 degrees (the roller rotating clockwise in operation).

Optionally, an abrasive particle removal member may be provided to help remove excess precisely shaped abrasive particles from the surface of the production tool when most or all of the cavities have been filled with abrasive particles. The abrasive particle removal member may be, for example, an air source such as an air wand (air wand), air shower, air knife, coanda effect nozzle, or blower for blowing off excess precisely shaped abrasive particles from the dispensing surface of the production tool. A contact device, such as a brush, a scraper, a wiper, or a doctor blade, may be used as the abrasive particle removal member. A vibrator, such as an ultrasonic horn, may be used as the abrasive particle removal member.

Alternatively, for production tools having cavities extending completely through the production tool, a vacuum source, such as a vacuum box or vacuum roll, positioned along a portion of the first web path after the abrasive particle feeder may be used to retain the precisely-shaped abrasive particles in the cavities. In this span or section of the first web path, the dispensing surface of the production tool may be reversed or have a large upward or downward slope approaching or exceeding 90 degrees to remove excess precisely shaped abrasive particles using gravity, slide or drop them off of the dispensing surface while holding the precisely shaped abrasive particles placed in the cavities by vacuum until the dispensing surface returns to an orientation that holds the precisely shaped abrasive particles in the cavities (due to gravity) or is released from the cavities onto the resin coated backing.

In embodiments where the abrasive particles are completely contained within the cavities of the production tool, the abrasive particle removal member can slide excess precisely shaped abrasive particles across the dispensing surface of the production tool and away from the production tool without interfering with the precisely shaped abrasive particles contained within the cavities. The removed excess precisely shaped abrasive particles can be collected and returned to the abrasive particle feeder for reuse. Alternatively, excess precisely shaped abrasive particles may be moved in a direction opposite to the direction of travel of the production tool through or toward the abrasive particle feeder, whereby they may fill unoccupied cavities.

Further details regarding the deposition of precisely shaped abrasive particles into the cavities of a production tool can be found, for example, in U.S. patent application publication number 2016-.

The diluted abrasive particles may be applied by any suitable means that does not remove the precisely shaped abrasive particles from the cavities; however, it is also possible to allow diluted abrasive particles to become stuck in the cavities together with precisely shaped abrasive particles. The diluted abrasive particles may be applied using an abrasive feeder. The abrasive particle feeder may be, for example, a vibratory feeder, a hopper, a chute, a silo, a drip coater, or a screw feeder. One preferred deposition method is drop coating. An abrasive particle removal member (e.g., as discussed above) may be used to help remove excess diluted abrasive particles from the surface of the production tool.

Typically, the minimum average size (e.g., average particle diameter) of the diluted abrasive particles is less than the longest dimension of the precisely shaped abrasive flakes. For example, the ratio of the average particle size of the diluted abrasive particles to the average longest dimension of the precisely shaped abrasive flakes can be less than 1/2, less than 1/3, less than 1/4, less than 1/5, less than 1/6, or even less than 1/8, however, this is not required.

If desired, grinding aid particles can be deposited with the diluted abrasive particles using a simultaneous or sequential procedure. Useful grinding aids include cryolite, fluoroborate salts (e.g., potassium tetrafluoroborate), fatty acid metal salts (e.g., zinc stearate or calcium stearate), salts of phosphate esters (e.g., potassium behenyl phosphate), phosphate esters, urea-formaldehyde resins, mineral oils, crosslinked silanes, crosslinked silicones, and/or fluorine-containing compounds.

Once the diluted abrasive particles have been deposited (as an open coating, a closed coating, or a patterned coating) on the dispensing surface of the production tool, they are contacted with a make layer precursor disposed on the backing. Once contacted, the abrasive particles adhere to the make layer precursor and remain adhered to the make layer precursor after the backing and make layer precursor are optionally separated from the production tool.

Referring now to fig. 2, wherein the oblique orientation of precisely shaped abrasive flakes is shown, at least a majority (e.g., at least 50%, at least 60%, at least 70%, at least 80%, or even at least 90%) of the precisely shaped abrasive flakes overhang the respective plurality of diluted abrasive particles after transfer.

Various methods may be employed to transfer the abrasive particles from the cavities of the production tool to the make layer precursor. Without being in a particular order, various methods include, for example: gravity assist, wherein the production tool and the dispensing surface are inverted such that the abrasive particles fall under gravity from the cavities onto the make layer precursor; a push assist, wherein each cavity in the production tool has two open ends, whereby abrasive particles can reside in the cavity and a portion of the abrasive particles extend through the back surface of the production tool; vibration assist, wherein the abrasive particle transfer roll or production tool is vibrated by a suitable source, such as an ultrasonic device, to shake the abrasive particles out of the cavity and onto the resin coated backing; and pressure assist, wherein each cavity in the production tool has two open ends or back surfaces or the entire production tool has a suitable porous structure, and the abrasive particle transfer roll has a plurality of pores and an internal source of pressurized air. The various embodiments listed above are not limited to use alone, and they may be mixed and matched as needed to more efficiently transfer abrasive particles from the cavities to the make layer precursor.

The make layer precursor is then at least partially cured (in an amount at least sufficient to fix the abrasive particles for further processing) to form a make layer. Thereafter, the make layer and abrasive particles are coated with the size layer precursor, and the size layer precursor is then at least partially cured (in an amount at least sufficient to fix the abrasive particles for the intended abrading process). Optionally, other process steps are known to those skilled in the art of making coated abrasive articles.

It will be apparent to those skilled in the art that the make layer precursor, optional size layer precursor, and optional make layer can be coated using conventional techniques, such as, for example, gravure coating, curtain coating, knife coating, spray coating, roll coating, reverse roll gravure coating, or rod coating.

Exemplary backings include those known in the art for making coated abrasive articles, including conventional seal-tape coated abrasive backings and apertured non-seal backings. Typically, the backing has two opposing major surfaces, but this is not required. The backing typically has a thickness in the range of about 0.02 millimeters to about 5 millimeters, advantageously in the range of about 0.05 millimeters to about 2.5 millimeters, and more advantageously in the range of about 0.1 millimeters to about 0.4 millimeters, although thicknesses outside of these ranges may also be used.

The backing may be flexible or rigid. Preferably, the backing is flexible. Exemplary backings include polymeric films (including primed films) (such as polyolefin films (e.g., polypropylene including biaxially oriented polypropylene, polyester films, polyamide films, cellulose ester films)), metal foils, meshes, foams (e.g., natural sponge materials or polyurethane foams), cloths (e.g., cloths made from fibers or yarns including polyester, nylon, silk, cotton, and/or rayon), paper, vulcanized fiber, nonwovens, combinations thereof, and treated versions thereof. The cloth backing may be woven, knitted or stitch-bonded, for example. The backing can also be a laminate of two materials (e.g., paper/film, cloth/paper, film/cloth).

The backing can be treated to include a presize layer (i.e., a barrier coating overlying the major surface of the backing on which the abrasive layer is applied), a backsize layer (i.e., a barrier coating overlying the major surface of the backing opposite the major surface on which the abrasive layer is applied), an impregnant (i.e., a barrier coating coated on all exposed surfaces of the backing), or a combination thereof. Useful pre-coat, backsize, and impregnant compositions include glues, phenolic resins, latex, epoxy resins, urea-formaldehyde, polyurethane, melamine-formaldehyde, neoprene, butyl acrylate, styrene, starch, and combinations thereof. Other optional layers known in the art may also be used (e.g., bonding layers; see, e.g., U.S. patent 5,700,302(Stoetzel et al)).

The backing treatment may contain additional additives such as fillers and/or antistatic materials (e.g., carbon black particles, vanadium pentoxide particles). The addition of the antistatic material reduces the tendency of the coated abrasive article to accumulate static electricity when sanding wood or wood-like materials. Additional details regarding antistatic backings and backing treatments can be found, for example, in U.S. Pat. Nos. 5,108,463(Buchanan et al), 5,137,542(Buchanan et al), 5,328,716(Buchanan), and 5,560,753(Buchanan et al).

Typically, at least one major surface of the backing is smooth (e.g., this surface may serve as the first major surface). The second major surface of the backing may include a non-slip or friction coating. Examples of such coatings include inorganic particles (e.g., calcium carbonate or quartz) dispersed within a binder.

The backing may comprise various additives. Examples of suitable additives include colorants, processing aids, reinforcing fibers, heat stabilizers, ultraviolet stabilizers, and antioxidants. Examples of useful fillers include clay, calcium carbonate, glass beads, talc, clay, mica, wood flour, and carbon black.

The backing may be a fiber reinforced thermoplastic such as, for example, the fiber reinforced thermoplastic described in U.S. patent 5,417,726(Stout et al), or may be an endless, endless belt such as, for example, the endless belt described in U.S. patent 5,573,619(Benedict et al). Likewise, the backing may be a polymeric substrate having hook stems protruding therefrom, such as, for example, the polymeric substrate described in U.S. Pat. No. 5,505,747(Chesley et al). Similarly, the backing may be a loop fabric, such as, for example, the loop fabric described in U.S. Pat. No. 5,565,011(Follett et al).

The make layer precursor and size layer precursor comprise respective curable binder precursor compositions, which may be the same or different.

Examples of curable binder precursor compositions used in the make layer precursor and/or size layer precursor include phenolic resins, urea-formaldehyde resins, acrylate resins, polyurethane resins, epoxy resins, aminoplast resins, and combinations thereof. The curable binder precursor composition may also include various additives including, for example, plasticizers, fillers, fibers, lubricants, surfactants, wetting agents, dyes, pigments, defoamers, dyes, coupling agents, plasticizers, and suspending agents.

Depending on any curable binder precursor composition selected, a suitable curing agent may be added to promote curing. Such curing agents will be apparent to those skilled in the art and may be, for example, thermally activated, photochemically activated, or both.

Optionally, a supersize layer may be applied to at least a portion of the size layer. When present, the supersize typically includes a grinding aid and/or an anti-loading material. The optional supersize layer may help prevent or reduce the accumulation of swarf (material abraded from the workpiece) between the abrasive particles, which accumulation may significantly reduce the cutting ability of the coated abrasive belt. Useful topcoats typically include grinding aids such as cryolite, tetrafluoroborate (e.g., potassium tetrafluoroborate), fatty acid metal salts (e.g., zinc stearate or calcium stearate), salts of phosphate esters (e.g., potassium behenyl phosphate), phosphate esters, urea-formaldehyde resins, mineral oils, crosslinked silanes, crosslinked silicones, and/or fluorine-containing compounds. Useful capstock materials are additionally described, for example, in U.S. patent 5,556,437(Lee et al). Typically, the amount of grinding aid incorporated into the coated abrasive product is from about 50 to about 400gsm, more typically from about 80 to about 300 gsm. The top coat may contain a binder, such as, for example, those used to prepare the size coat or the make coat, but it need not have any binder.

Further details regarding coated abrasive belts comprising an abrasive layer secured to a backing are well known, wherein the abrasive layer comprises abrasive particles and a make layer, a size layer, and optionally a supersize layer, and such details can be found, for example, in U.S. Pat. Nos. 4,734,104(Broberg), 4,737,163(Larkey), 5,203,884(Buchanan et al), 5,152,917(Pieper et al), 5,378,251(Culler et al), 5,417,726(Stout et al), 5,436,063(Follett et al), 5,496,386(Broberg et al), 5,609,706(Benedict et al), 5,520,711(Helmin), 5,954,844(Law et al), 5,961,674(Gagliardi et al), 4,751,138(Bange et al), 5,766,277(DeVoe et al), 6,077,601(DeVoe et al), 6,228,133(Thur et al), and 5,975,988 (Christiserson).

The coated abrasive tape according to the present invention can be used for abrading a workpiece. Preferred workpieces include metals (e.g., aluminum, nickel alloys, stainless steel, mild steel), composites, plastics, and wood.

Referring now to fig. 6, in one exemplary embodiment, a coated abrasive article 600 includes a backing 610 having a major surface 612. A make layer 630 is disposed on and secured to the backing 610. Abrasive layer 620 contacts make layer 630 and is secured to the make layer. The abrasive layer 620 includes a precisely shaped sheet 632 of abrasive material and dilute abrasive particles 624. Precisely shaped abrasive sheet 622 is disposed at a dihedral angle β of less than or equal to 60 degrees relative to major surface 612 of backing 610. At least a majority (e.g., at least 50%, at least 60%, at least 70%, at least 80%, or even at least 90%) of the precisely shaped abrasive sheets 632 are each suspended above a respective plurality of diluted abrasive particles 624. Size layer 670 is disposed on make layer 630 and abrasive layer 620.

Referring now to fig. 7, in another exemplary embodiment, a coated abrasive article 700 includes a coated abrasive article 700 having a backing 710 with a major surface 712. Primer layer 730 is disposed on and secured to backing 710. The abrasive layer 720 contacts the make coat 730 and is secured to the make coat. Abrasive layer 720 includes islands 725. Each island 725 contains at least one precisely shaped abrasive sheet 722 and dilute abrasive particles 724. The islands 725 are separated from each other. A size layer 770 is disposed on the make layer 730 and the abrasive layer 720. The precisely-shaped abrasive sheet 722 is generally aligned with respect to the longitudinal axis 790 of the coated abrasive article 700.

For coated abrasive articles 800 that are used with a rotational motion (e.g., the coated abrasive disk shown in fig. 8), the precisely-shaped abrasive sheet 822 is generally aligned with respect to the rotational axis (875, perpendicular to the page) of the coated abrasive article 800.

Coated abrasive articles according to the present invention may be used to abrade a workpiece. One such method includes frictionally contacting at least a portion of an abrasive layer of a coated abrasive article with at least a portion of a surface of a workpiece, and moving at least one of the coated abrasive article or the workpiece relative to the other to abrade at least a portion of the surface.

Examples of workpiece materials include metals, metal alloys, dissimilar metal alloys, ceramics, glass, wood-like materials, composites, painted surfaces, plastics, reinforced plastics, stone, and/or combinations thereof. The workpiece may be flat or have a shape or profile associated therewith. Exemplary workpieces include metal parts, plastic parts, particle board, camshafts, crankshafts, furniture, and turbine blades.

Coated abrasive articles according to the present invention may be used manually and/or in conjunction with a machine. When abrading, it is common to move at least one of the coated abrasive article and the workpiece relative to the other, or both, relative to each other.

The milling may be performed under wet or dry conditions. Exemplary liquids for wet milling include water, water containing conventional rust inhibiting compounds, lubricants, oils, soaps, and cutting fluids. The liquid may also contain defoamers, degreasers and/or the like.

Selected embodiments of the present disclosure

In a first embodiment, the present disclosure provides a method of making a coated abrasive article comprising the sequential steps of:

a) providing a production tool comprising a carrier member having a dispensing surface, the production tool having a precisely shaped cavity therein;

c) depositing diluted abrasive particles on the dispensing surface;

In a second embodiment, the present disclosure provides the method according to the first embodiment, wherein the sequential steps further comprise:

h) at least partially curing the curable size layer precursor.

In a third embodiment, the present disclosure provides a method according to the first or second embodiment, wherein said steps a) to e) are continuous.

In a fourth embodiment, the present disclosure provides a method according to any one of the first to third embodiments, wherein after step b) and before step c), at least a majority of the precisely shaped abrasive sheets are oriented at respective dihedral angles less than or equal to 60 degrees relative to the dispensing surface of the tool.

In a fifth embodiment, the present disclosure provides a method according to any one of the first to fourth embodiments, wherein after step c), at least a majority of the precisely-shaped abrasive sheets overhang a corresponding plurality of the diluted abrasive particles.

In a sixth embodiment, the present disclosure provides a method according to any one of the first to fifth embodiments, wherein the diluted abrasive particles comprise crushed abrasive particles.

In a seventh embodiment, the present disclosure provides a method according to any one of the first to sixth embodiments, wherein after step c), the precisely-shaped abrasive flakes and the diluted abrasive particles form a closed abrasive coating.

In an eighth embodiment, the present disclosure provides a method according to any one of the first to seventh embodiments, wherein after step c), the precisely-shaped abrasive flakes and the diluted abrasive particles form an open abrasive coating.

In a ninth embodiment, the present disclosure provides a coated abrasive article made according to the method of any one of the first to eighth embodiments.

In a tenth embodiment, the present disclosure provides a coated abrasive article comprising:

a backing having a first major surface;

a make layer disposed on and secured to the backing;

In an eleventh embodiment, the present disclosure provides a coated abrasive article according to the tenth embodiment, wherein the precisely-shaped abrasive sheet is generally aligned with respect to a longitudinal axis of the coated abrasive article.

In a twelfth embodiment, the present disclosure provides a coated abrasive article according to the tenth embodiment, wherein the precisely-shaped abrasive sheet is generally aligned with respect to the rotational axis of the coated abrasive article.

In a thirteenth embodiment, the present disclosure provides the coated abrasive article of any one of the tenth to twelfth embodiments, wherein the precisely-shaped abrasive sheet comprises a triangular sheet.

In a fourteenth embodiment, the present disclosure provides the coated abrasive article of any one of the tenth to thirteenth embodiments, wherein after step c), the precisely-shaped abrasive sheet comprises a rectangular sheet.

In a fifteenth embodiment, the present disclosure provides the coated abrasive article of any one of the tenth to fourteenth embodiments, wherein the diluted abrasive particles comprise crushed abrasive particles.

In a sixteenth embodiment, the present disclosure provides the coated abrasive article of any one of the tenth to fifteenth embodiments, wherein the precisely-shaped abrasive sheet and the diluted abrasive particles form a closed abrasive coating.

In a seventeenth embodiment, the present disclosure provides the coated abrasive article of any one of the tenth to fifteenth embodiments, wherein the precisely-shaped abrasive sheets and the diluted abrasive particles form an open abrasive coating.

In an eighteenth embodiment, the present disclosure provides the coated abrasive article of any one of the tenth to seventeenth embodiments, wherein the precisely-shaped abrasive sheets are positioned substantially according to a predetermined pattern.

In a nineteenth embodiment, the present disclosure provides a coated abrasive article comprising:

a backing having a major surface;

a make layer disposed on and secured to the backing;

In a twentieth embodiment, the present disclosure provides the coated abrasive article of the nineteenth embodiment, wherein the diluted abrasive particles are disposed primarily beneath respective overhangs of at least a majority of the precisely-shaped abrasive flakes.

In a twenty-first embodiment, the present disclosure provides the coated abrasive article of the nineteenth or twentieth embodiment, wherein the islands are separated from each other by a distance that is at least twice the minimum distance between nearest precisely-shaped abrasive sheets of adjacent islands.

In a twenty-second embodiment, the present disclosure provides the coated abrasive article of any one of the nineteenth to twenty-first embodiments, wherein the precisely-shaped abrasive sheets are positioned substantially according to a predetermined pattern.

In a twenty-third embodiment, the present disclosure provides the coated abrasive article of any one of the nineteenth to twenty-second embodiments, wherein the precisely-shaped abrasive sheet is generally aligned with respect to a longitudinal axis of the coated abrasive article.

In a twenty-fourth embodiment, the present disclosure provides the coated abrasive article of any one of the nineteenth to twenty-second embodiments, wherein the precisely-shaped abrasive sheet is generally aligned with respect to the rotational axis of the coated abrasive article.

In a twenty-fifth embodiment, the present disclosure provides a method of abrading a workpiece, the method comprising:

providing a coated abrasive article according to any one of the ninth to twenty-fourth embodiments;

frictionally contacting at least a portion of the coated abrasive article with at least a portion of a surface of the workpiece; and

moving at least one of the coated abrasive article or the workpiece relative to the other to abrade at least a portion of the surface.

Objects and advantages of this disclosure are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this disclosure.

Examples

All parts, percentages, ratios, and the like in the examples and the remainder of the specification are by weight unless otherwise indicated.

Unless otherwise indicated, all other reagents were obtained or purchased from fine chemical suppliers such as Sigma Aldrich Company of st.

Abbreviations of units used in the examples: DEG C: c, centigrade degree; cm is equal to centimeter; g is gram; g/m²Grams per square meter; rpm is the revolutions per minute; mm is millimeter; wt.% ═ weight percent.

The materials used in the examples are described in table 1 below:

TABLE 1

Example 1

Coated abrasive article with 90 degree SAP orientation

A production tool with vertically oriented triangular openings, typically configured as described in U.S. patent application publication No. 2016/0311081 a1(Culler et al) (1.875 mm long, 0.785mm wide, 1.62mm deep, 0.328mm wide at the base), arranged in a rectangular array (1.978 mm longitudinal spacing, 0.886mm transverse spacing, all long dimensions in the same direction) was used to place the abrasive particles.

In a first step, most of the cavities of the production tool are filled with P36 grade SAP. Using 3 inches (240-cm)²) Wooster Spiffy brush carefully removed excess SAP. About 9.2 grams of SAP particles were loaded onto a 37 square inch area of the tool surface.

In the second step, the gap between SAP and the lumen wall was filled with P80 grade crushed garnet particles. The excess crushed garnet grains were carefully removed with a 3 inch Wooster Spiffy brush. About 4.4g of crushed garnet granule particles were loaded onto a 37 square inch area of the tool surface.

Primer layer precursor

The fiber disc backing was coated with primer resin 1 by brush to a weight of 3.0 grams to 3.1 grams.

Transfer of abrasive ore to make layer precursor

The fiber disc backing with make layer precursor is then flipped over and brought into contact with the abrasive particle-laden surface of the production tool. The assembly is clamped together with a binder and then flipped over to facilitate gravity transfer of the abrasive particles to the make layer precursor. The vibration of the production tool further promotes the transfer of the abrasive particles. The production tool is separated from the make layer precursor and abrasive particles such that both the SAP and the crushed abrasive particles have been transferred to the make resin layer. The make layer precursor of the coated disc was pre-cured at 90 ℃ for 1 hour and then at 103 ℃ for 3 hours.

Coating with compound glue

The pre-cured disc was then coated with curable size resin 1 by brush. Excess size resin was removed with a dry brush until the immersed glossy appearance was reduced to a matte appearance. The size compounding pan was weighed to determine the size compounding resin weight. The size resin is added in an amount of 11.5g to 13.0g of size resin coating (i.e., size layer precursor). The discs were cured at 90 ℃ for 90 minutes and then at 103 ℃ for 16 hours. The cured discs were flexed orthogonally on a 1.5 inch (3.8cm) diameter roll. The surface of the resulting coated abrasive article was characterized by optical microscopy. The results are shown in fig. 9A and 9B.

Comparative example A

Coated abrasive article with 90 degree SAP orientation

The procedure of example 1 was repeated except that the SAP loaded on the production tool was first transferred to the make layer precursor and then the P80 grade crushed garnet particles were directly coated onto the fibrous disk substrate by drop coating (the abrasive particles fall by gravity onto the make layer precursor). The results are shown in fig. 10A and 10B.

Example 2

Coated abrasive article with 60 degree SAP orientation

The procedure of example 1 was repeated except that: (1) production tools with 60 ° oriented triangular openings (length 1.875mm, width 1.1775mm, depth 1.62mm, base width 0.328mm) arranged in rectangular arrays (longitudinal spacing 1.978mm, transverse spacing 1.229mm, all long dimensions in the same direction); and (2) loading 8.3g of SAP, then 6.8g P80 grade crushed garnet grains onto a production tool. The results are shown in fig. 11A and 11B.

Comparative example B

Coated abrasive article with 60 degree SAP vertical orientation

The procedure of example 2 was repeated except that the SAP loaded on the production tool was first transferred onto the make layer precursor and then 8.2g P80 grade crushed garnet particles were directly coated on the make layer precursor by drop coating. The results are shown in fig. 12A and 12B.

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

Claims

1. A method of making a coated abrasive article comprising the sequential steps of:

c) depositing diluted abrasive particles on the dispensing surface;

2. The method of claim 1, wherein the sequential steps further comprise:

h) at least partially curing the curable size layer precursor.

3. The method of claim 1, wherein the steps a) through e) are continuous.

4. The method of claim 1, wherein after step b) and before step c), at least a majority of the precisely shaped abrasive sheets are oriented at respective dihedral angles less than or equal to 60 degrees relative to the dispensing surface of the tool.

5. The method of claim 1, wherein after step c), at least a majority of the precisely-shaped abrasive flakes overhang a corresponding plurality of the diluted abrasive particles.

6. The method of claim 1, wherein the diluted abrasive particles comprise crushed abrasive particles.

7. The method of claim 1, wherein after step c), the precisely-shaped abrasive flakes and the diluted abrasive particles form a closed abrasive coating.

8. The method of claim 1, wherein after step c), the precisely-shaped abrasive flakes and the diluted abrasive particles form an open abrasive coating.

9. A coated abrasive article made by the method of claim 1.

10. A coated abrasive article, comprising:

a backing having a first major surface;

a make layer disposed on and secured to the backing;

the compound glue layer is arranged on the bottom glue layer and the abrasive material layer.

11. The coated abrasive article of claim 10 wherein the precisely-shaped abrasive sheet is generally aligned with respect to a longitudinal axis of the coated abrasive article.

12. The coated abrasive article of claim 10 wherein the precisely-shaped abrasive sheet is generally aligned with respect to an axis of rotation of the coated abrasive article.

13. The coated abrasive article of claim 10 wherein the precisely-shaped abrasive flakes comprise triangular flakes.

14. The coated abrasive article of claim 10 wherein after step c), the precisely-shaped abrasive sheet comprises a rectangular sheet.

15. The coated abrasive article of claim 10 wherein the diluted abrasive particles comprise crushed abrasive particles.

16. The coated abrasive article of claim 10 wherein the precisely-shaped abrasive flakes and the diluted abrasive particles form a closed abrasive coating.

17. The coated abrasive article of claim 10 wherein the precisely-shaped abrasive flakes and the diluted abrasive particles form an open abrasive coating.

18. The coated abrasive article of claim 10 wherein the precisely-shaped abrasive sheet is positioned substantially according to a predetermined pattern.

19. A coated abrasive article comprising:

a backing having a major surface;

a make layer disposed on and secured to the backing;

20. The coated abrasive article of claim 19 wherein the diluted abrasive particles are disposed primarily under respective overhangs of at least a majority of the precisely-shaped abrasive flakes.

21. The coated abrasive article of claim 19 wherein the islands are separated from each other by a distance that is at least twice the minimum distance between nearest precisely-shaped abrasive sheets of adjacent islands.

22. The coated abrasive article of claim 19 wherein the precisely-shaped abrasive sheet is positioned substantially according to a predetermined pattern.

23. The coated abrasive article of claim 19 wherein the precisely-shaped abrasive sheet is generally aligned with respect to a longitudinal axis of the coated abrasive article.

24. The coated abrasive article of claim 19 wherein the precisely-shaped abrasive sheet is generally aligned with respect to an axis of rotation of the coated abrasive article.