Mesh abrasive article having a slit pattern and method of manufacturing the same

Abstract

Aspects of the present disclosure relate to a method for making a mesh abrasive article, comprising providing an abrasive sheet having a base layer of a continuous impermeable substrate and forming a pattern of slits in the sheet to create a slitted abrasive sheet, which is then stretched until a strain up to a flattening strain threshold is reached, causing the slits to open as stressed regions, forming a plurality of apertures, thereby forming an apertured abrasive sheet.

Description

[Background technology]

[0001] 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 an abrasive disc attached to the tool and then draw a vacuum through the disc, i.e., from the abrasive side to the backside of the disc, and into a dust collection system. For this purpose, many abrasives are supplied with holes drilled into them to facilitate dust extraction. As an alternative to drilling holes into abrasive discs for dust extraction, there are commercially available products in which the abrasive is coated onto the fibers of a net-like knitted support, with loops woven into the backside. These loops function as the loop portion of a hook-and-loop (Velcro) attachment system for attachment to the tool. Net-type products are known to offer superior dust extraction and / or anti-clogging properties when used on substrates where conventional abrasives are significantly more susceptible to clogging.

[0002] Conventional mesh abrasive articles have a uniform distribution of abrasive particles on the surface of the mesh sheet, but the woven nature of the fiber bundles to form ridges can result in uneven flatness. Summary of the Invention

[0003] One aspect of the present disclosure describes a method for producing a mesh abrasive article, starting with an abrasive sheet having a base layer with a continuous, impermeable substrate. The sheet is slit in a pattern to obtain a slitted abrasive sheet. The slits extend through a first surface of the abrasive sheet. The slitted abrasive sheet is subjected to a tensile stress until it reaches a flattening strain threshold, which results in the slits opening into stressed regions and forming a plurality of openings.

[0004] In one embodiment, this process results in an apertured abrasive sheet that, when tested using a topographical profile method, has a specific height to average material thickness ratio (0.6 to 1.7).

[0005] A further aspect of the present disclosure relates to mesh abrasive articles made using the above method.

[0006] A further aspect of the present disclosure describes a mesh abrasive article comprising a planar coated abrasive sheet and an adhesive layer. The coated abrasive sheet comprises a plurality of strands and a plurality of openings formed by straining a plurality of slits formed in the sheet. A plurality of bridge regions are formed between the ends of the openings in a first direction, and the strands extend diagonally between the plurality of bridge regions. Furthermore, the strands are connected to each other in the bridge regions, and some strands are separated from each other by the plurality of openings. This straining is performed so that none of the strands overlap after lamination. The coated abrasive sheet is laminated to the adhesive layer, thereby obtaining a breathable mesh abrasive article. [Brief explanation of the drawings]

[0007] To easily identify a description of a particular element or operation, the most significant digit(s) of a reference number indicates the number of the figure in which that element is first introduced.

[0008] [Figure 1] FIG. 1 shows a polishing sheet according to one embodiment of the present invention.

[0009] [Figure 2] FIG. 2 shows a slit abrasive sheet according to one embodiment of the present invention.

[0010] [Figure 3] FIG. 3 shows a slit abrasive sheet according to one embodiment.

[0011] [Figure 4] FIG. 4 shows an apertured abrasive sheet according to one embodiment.

[0012] [Figure 5A] FIG. 5A shows a first side of a mesh abrasive article according to one embodiment.

[0013] [Figure 5B] FIG. 5B shows a slitted abrasive sheet according to one embodiment.

[0014] [Figure 6] FIG. 6 shows a flow chart of a method for making a mesh abrasive article according to one embodiment.

[0015] [Figure 7] FIG. 7 shows a take-up device for a slit abrasive sheet according to one embodiment.

[0016] [Figure 8A] FIG. 8A shows a polishing sheet with diamond slit patterns of varying size and expansion, according to one embodiment. [Figure 8B] FIG. 8B shows a polishing sheet with diamond slit patterns of varying size and expansion, according to one embodiment. [Figure 9A] FIG. 9A shows a polishing sheet with diamond slit patterns of varying size and expansion, according to one embodiment. [Figure 9B] FIG. 9B shows a polishing sheet with diamond slit patterns of varying size and expansion, according to one embodiment.

[0017] [Figure 10A] FIG. 10A shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0018] [Figure 10B] FIG. 10B shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0019] [Figure 11A] FIG. 11A shows a reticulated abrasive article having openings of two different sizes and / or shapes that allow it to be expandable in at least one direction.

[0020] [Figure 11B] FIG. 11B shows a screen abrasive article with openings of two different sizes and / or shapes that allow it to be expandable in at least one direction.

[0021] [Figure 12A] FIG. 12A shows a screen abrasive article with openings of three different sizes and / or shapes that allow it to be expandable in at least one direction.

[0022] [Figure 12B] FIG. 12B shows a screen abrasive article with openings of three different sizes and / or shapes that allow it to be expandable in at least one direction.

[0023] [Figure 13A] FIG. 13A shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0024] [Figure 13B] FIG. 13B shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0025] [Figure 14A] FIG. 14A shows a screen abrasive article having openings of three different sizes and / or shapes that allow it to be expandable in at least one direction.

[0026] [Figure 14B]FIG. 14B shows a screen abrasive article with openings of three different sizes and / or shapes that allow it to be expandable in at least one direction.

[0027] [Figure 15A] FIG. 15A shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0028] [Figure 15B] FIG. 15B shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0029] [Figure 16A] FIG. 16A shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0030] [Figure 16B] FIG. 16B shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0031] [Figure 17A] FIG. 17A illustrates one aspect of the subject matter according to one embodiment of the present invention.

[0032] [Figure 17B] FIG. 17B illustrates one aspect of the subject matter according to one embodiment of the present invention.

[0033] [Figure 18A] FIG. 18A shows a screen abrasive article with openings of three different sizes and / or shapes that allow it to be expandable in at least one direction.

[0034] [Figure 18B] FIG. 18B shows a screen abrasive article with openings of three different sizes and / or shapes that allow it to be expandable in at least one direction.

[0035] [Figure 19A] FIG. 19A shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0036] [Figure 19B] FIG. 19B shows a non-diamond slit pattern that allows for expansion of the abrasive sheet slit in at least one direction.

[0037] [Figure 20A] FIG. 20A shows a screen abrasive article with openings of two different sizes and / or shapes that allow it to be expandable in at least one direction.

[0038] [Figure 20B] FIG. 20B shows a screen abrasive article with openings of two different sizes and / or shapes that allow it to be expandable in at least one direction.

[0039] [Figure 21A] FIG. 21A shows a screen abrasive article having openings of two different sizes and / or shapes that allow it to be expandable in at least two directions.

[0040] [Figure 21B] FIG. 21B shows a screen abrasive article having openings of two different sizes and / or shapes that allow it to be expandable in at least two directions.

[0041] [Figure 22A] FIG. 22A shows a screen abrasive article that includes multiple expandable regions that allow it to be expandable in at least two directions (eg, radially). [Figure 22B] FIG. 22B shows a screen abrasive article that includes multiple expandable regions that allow it to be expandable in at least two directions (eg, radially). [Figure 22C] FIG. 22C shows a screen abrasive article that includes multiple expandable regions that allow it to be expandable in at least two directions (eg, radially).

[0042] [Figure 23A] FIG. 23A shows a screen abrasive article having openings of two different sizes and / or shapes that allow it to be expandable in at least two directions.

[0043] [Figure 23B] FIG. 23B shows a screen abrasive article with openings of two different sizes and / or shapes that allow it to be expandable in at least two directions.

[0044] [Figure 24A] FIG. 24A shows a screen abrasive article having apertures of three different sizes and / or shapes that converge to allow expansion in at least three directions. [Figure 24B] FIG. 24B shows a screen abrasive article having apertures of three different sizes and / or shapes that converge to allow expansion in at least three directions.

[0045] [Figure 25] FIG. 25 shows an example of a mesh abrasive article according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0046] Aspects of the present disclosure relate to mesh abrasive articles made with an expandable slit pattern on a coated abrasive sheet, whereby when the slitted abrasive sheet is strained, the slits expand into openings, thereby forming multiple strands on the slitted abrasive sheet.

[0047] The pattern may be a single slit pattern, a multiple slit pattern, a composite pattern, or a combination thereof. In some embodiments, the pattern may include skip slits, and when the polishing sheet is strained to a flattening strain threshold, the ratio of the height of the polishing surface after lamination to the average material thickness of the polishing sheet is in the range of 0.6 to 1.7, as measured using a topographical profile method.

[0048] Furthermore, the tensioning may induce at least one twist in the strands when strained up to a flattening strain threshold, but no folds of the strands occur when the slitted abrasive sheet is stacked or pressed flat. In one embodiment, no folds occur when the slitted abrasive sheet is strained up to a flattening strain threshold and pressed flat. Also, in one embodiment, after tensioning, less than 5% of the surface area of ​​the edges of the abrasive sheet protrudes outside the plane of the abrasive sheet.

[0049] The method may further include laminating the base layer to an adhesive layer to form a mesh abrasive article.

[0050] The adhesive layer may be planar and have an open area of ​​at least 20%. In some embodiments, air can flow through the adhesive layer at a rate of at least 1.0 L / s, allowing the mesh abrasive article to remove dust from the abrasive surface. The resulting mesh abrasive article may have an air permeability of greater than 377 cubic feet per minute per square foot, as measured according to ASTM D737-18(2023).

[0051] The lamination process may include applying an adhesive to the base layer or the adhesive layer, or applying pressure or heat to the base layer or the adhesive layer. The adhesive layer may be a mesh support with woven loops or a pressure-sensitive adhesive layer that can be attached directly to a back-up pad.

[0052] Other steps in the method may include wrapping the slit abrasive sheet multiple times around a core member for tensioning, cutting the mesh abrasive article in the cross and / or machine direction, and securing the apertured abrasive sheet. Mesh abrasive articles formed by this method are also disclosed herein.

[0053] In some embodiments of the method, the first surface of the polishing sheet may be a functional layer, e.g., a structured abrasive, while the second surface may be a base layer, which may be a polymeric material, such as a stretchable, elastic polymeric material having an elongation to break of at least 100%, or may be a coated paper.

[0054] In at least one embodiment, the tensioning step may be performed by wrapping the slitted abrasive sheet multiple times around an axially extending core member, exerting a tension force on the slitted abrasive sheet in the machine direction, thereby causing plastic deformation of the slitted abrasive sheet. The tension force may be at least 1 lb / in2. The method may also include fixing the apertured abrasive sheet using heat, pressure, or both. The fixation results in a fixed aperture area of ​​at least 10% of the stressed aperture area of ​​one of the plurality of apertures.

[0055] The heat may be applied via an in-line oven to secure the plurality of apertures, and the heat may be at least 120°C and may be applied by blown hot air. The pressure applied during the securing may be at least 5 kg / cm (linear) and may be applied by a roll nip. The method also includes a mesh abrasive article formed by the processes disclosed herein, and may also include cutting the mesh abrasive article in the cross direction and / or the machine direction.

[0056] The plurality of slits are slits when the mesh abrasive article is in an unstressed state, but at least some of the slits become openings when the mesh abrasive article is in a stressed state. Briefly, the method of making a mesh abrasive article disclosed herein includes providing an abrasive sheet having a continuous impermeable backing as a base layer.

[0057] The abrasive sheet has a first surface and a second surface opposite the first surface. The method further includes forming a pattern of slits in the abrasive sheet and stretching the slit abrasive sheet until a flattening strain threshold is reached to form a plurality of apertures, forming an apertured abrasive sheet. The mesh abrasive article may also include attaching the base layer of the abrasive sheet to an adhesive layer using an adhesive, heat, pressure, or any combination thereof.

[0058] Further aspects of the present disclosure relate to a method for making a mesh abrasive article. The method includes providing an abrasive sheet having a first surface and a second surface opposite the first surface. The abrasive sheet includes a base layer comprising a resilient polymeric material having an elongation to break of at least 100%.

[0059] The method also includes forming skip slits in the polishing sheet along the machine direction or the cross direction to obtain a slitted polishing sheet having a plurality of slits formed therein, the plurality of slits extending through the first surface.

[0060] The method further includes tensioning the slitted abrasive sheet to form an apertured abrasive sheet, wherein the tensioning causes the slits in the slitted abrasive sheet to form apertures having stressed open areas.

[0061] In one embodiment, the slit abrasive sheet is wrapped multiple times around an axially extending core member to form a stretched, open abrasive sheet, the wrapping being in the machine direction and tensioning the slit abrasive sheet to cause plastic deformation of the abrasive sheet.

[0062] The method also includes fixing the apertured abrasive sheet to form a mesh abrasive article. In one embodiment, the apertures may be at least partially fixed to have a fixed aperture area by applying heat. In one embodiment, the apertures may also be at least partially fixed by applying pressure. Aspects of the present disclosure also relate to mesh abrasive articles made by the methods described herein.

[0063] An aspect of the present disclosure relates to a mesh abrasive article comprising a planar coated abrasive sheet and an adhesive layer. The coated abrasive sheet comprises a plurality of strands and a plurality of openings formed by straining a plurality of slits in the coated abrasive sheet. The bridge regions are formed between the ends of the openings in the cross direction or machine direction, and the strands extend diagonally between the bridge regions. At least some of the strands are separated from one another by the openings and are strained to prevent any of the strands from folding over after lamination. The coated abrasive sheet is laminated to the adhesive layer, resulting in a breathable mesh abrasive article.

[0064] In some embodiments, the mesh abrasive article has an air permeability of greater than 377 cubic feet per minute per square foot as measured in accordance with ASTM D737-18(2023). The coated abrasive sheet may have an abrasive major surface and a non-abrasive back major surface, wherein no portion of the back major surface is exposed above the abrasive major surface.

[0065] In summary, the mesh abrasive article disclosed herein comprises a planar coated abrasive sheet having a plurality of strands and openings formed by distorting a plurality of slits, the coated abrasive sheet being laminated to an adhesive layer to provide a breathable mesh abrasive article having predetermined breathability and a major abrasive surface.

[0066] Aspects of the present disclosure also relate to a kit including a first mesh abrasive article having a particular grit size and a first opening area, and a second mesh abrasive article having the same grit size but a different second opening area, where the first and second mesh abrasive articles have different cutting speeds or finishing characteristics, allowing a user to select an appropriate mesh abrasive article for a particular application.

[0067] Aspects of the present disclosure also relate to a method and apparatus for manufacturing a mesh abrasive article. The method may include forming a pattern of slits in a flexible abrasive sheet, stretching the slitted abrasive sheet to open the slits, and clamping the apertured abrasive sheet so that the slits are held at least partially open to form a mesh abrasive article (which may be a coated abrasive article). In one embodiment, the clamping may include applying heat to the apertured abrasive sheet at a temperature of at least 120°C.

[0068] Some prior art has discussed using slits to form openings, but these openings have not been known to be useful in the context of mesh abrasive articles.In at least one embodiment, it has been discovered that the use of a flexible base layer, as known in flexible abrasive sheets, is suitable for stretching rather than breaking when subjected to tensile force.Therefore, instead of the sheet breaking when tensile force is applied, the formed mesh abrasive article will have openings that are useful for dust removal while maintaining structural integrity.

[0069] The present disclosure has been proven to offer several manufacturing advantages. First, the present method of forming slits in an abrasive sheet, unlike traditional methods of punching holes or applying abrasive particles to a mesh, eliminates the need to remove burrs and other debris when converting the precursor abrasive article into a slit form, thereby saving time and resources in the manufacturing process.

[0070] Second, the use of mesh abrasive articles made from slit abrasive sheets can result in a flatter abrasive surface, which can produce a finer finish and allow more abrasive material to contact the work surface.

[0071] Third, the slits can be generated by mechanically cutting the abrasive sheet or by using a laser, which may be more efficient and precise than other techniques.

[0072] Finally, the slits can be adjusted depending on the application, allowing for more versatile product design. For example, a slitted abrasive sheet can be expanded or distorted beyond a certain threshold to increase the open area and reduce the cutting speed while maintaining the same abrasive grain size. This design flexibility allows the product to be adapted to a variety of applications.

[0073] 1 shows an abrasive article 101, which is used to illustrate the construction of an exemplary abrasive article 101. The abrasive article 101 may be a coated abrasive article with an adhesive layer. Various examples of the abrasive article 101 are provided as film disc products commercially available under the trademark "Hookit" from 3M Company (Saint Paul, Minnesota, USA).

[0074] For example, the abrasive article 101 may include a functional layer 102, which is a coated abrasive layer used to abrade materials. The functional layer 102 may also include a supersize coating (anti-clogging layer).

[0075] The functional layer 102 may be disposed on a base layer 104. The base layer 104 may be formed from a material configured to deform in response to a tensile force and may have a degree of strength to provide structural integrity to the functional layer 102.

[0076] In some embodiments, the base layer 104 may comprise an elastomeric film. The elastomeric film may be monolithic or may be a multilayer composite film manufactured by coextrusion, thermal lamination, or adhesive lamination. Examples of materials that can be used for the elastomeric film include polyolefins, polyesters (e.g., those known under the trade name "HYTREL" from EI du Pont de Nemours & Co., Wilmington, Delaware, USA), polyamides, styrene / butadiene copolymers (e.g., "KRATON" from Kraton Polymers, Houston, Texas, USA), polyurethane elastomers (e.g., those known under the trade names "ESTANE 5701," "ESTANE 5702," and "ESTANE 58887"), chloroprene rubber, ethylene / propylene rubber, polybutadiene rubber, polyisoprene rubber, natural or synthetic rubber, butyl rubber, silicone rubber, EPDM rubber, or combinations thereof. Further examples of useful elastomeric films include those described in the following U.S. Patents: 2,871,218 (Schollenberger), 3,645,835 (Hodgson), 4,595,001 (Potter et al.), 5,088,483 (Heinecke), 6,838,589 (Liedtke et al.), and Reissue Patent No. RE33353 (Heinecke). Further useful examples include polyurethane elastomer films coated with a pressure-sensitive adhesive known under the trade name "TEGADERM," available from 3M Company (Saint Paul, Minnesota, USA).

[0077] Alternatively, the base layer 104 may be formed from a polymer derived from 0-50% by weight of a carboxylic acid resin (e.g., acrylic acid), 0-50% by weight of an alkyl acrylate, alkyl methacrylate, and alkyl ethacrylate (e.g., ethyl acrylate), 0-50% by weight of an unsaturated acetate (e.g., vinyl acetate), and the remainder an α-olefin (e.g., ethylene). These resins may be fully or partially neutralized with a metal hydroxide or other suitable basic material.

[0078] In preferred embodiments, the base layer 104 may have an elongation at break measured at room temperature of at least 100%, at least 200%, at least 300%, at least 400%, or at least 500%. Optionally, the base layer 104 may have an elongation at break at room temperature of up to 1000%, up to 800%, up to 700%, up to 600%, or up to 500%.

[0079] As used herein, elongation at break is measured in accordance with test method D882-12, "Standard Test Method for Tensile Properties of Thin Film Plastics," published by ASTM International (published September 2012), at an elongation rate of 10% of the gauge length per minute.

[0080] Materials suitable for the base layer 104 are preferably non-tacky at room temperature. In this disclosure, "non-tacky" refers to a material that meets the Dahlquist Criterion, which means that the storage modulus (G') is about 3 x 10 5 This means that the storage modulus is less than 10 Pascals (10 rad / sec, measured at room temperature). This definition is also found in U.S. Patent No. 6,884,504 (Liu et al.) and in "Handbook of Pressure Sensitive Adhesive Technology," 2nd Edition (1989), pp. 172-176. Materials with a storage modulus below this threshold are considered tacky by the Dahlquist criteria.

[0081] Suitable materials for the base layer 104 can have a modulus of elasticity ranging from 5 to 20,000 MPa, or alternatively from 10 to 10,000 MPa, or from 20 to 5,000 MPa, or from 30 to 1,000 MPa, or from 30 to 500 MPa. One method for measuring the modulus of elasticity is to expose a cross section of the layer and perform an indentation test. This indentation test can be performed according to the principles of ASTM E2546, "Standard Practice for Instrumental Indentation Testing." However, instead of using the slope of the unload curve to determine contact stiffness, especially for soft materials susceptible to creep, the Continuous Stiffness Method on an Agilent G200 can be used, which provides a more accurate determination of contact stiffness.

[0082] In one embodiment, the upper glass transition temperature (Tg) of the base layer 104 is set higher than the operating temperature of the functional layer 102 to limit thermal relaxation caused by polishing and prevent deformation of the material. Such control of Tg can be achieved by blending various polymers with different glass transition temperatures.

[0083] To verify the integrity of the chip, a calibration standard of fused silica with a nominal modulus of 72 GPa may be tested before and after testing. All tests were performed using an Agilent G200 nanoindenter with a DCM head and a Berkovich diamond probe at a strain rate of 0.05 s. -1 The test is performed assuming a constant σ and a Poisson's ratio of 0.3. The specimen cross section is exposed by microtoming, mounted in a 1-inch diameter epoxy pack, and finally polished with a 0.1 μm diamond lapping film. The following test conditions may be used: (1) surface approach distance: 5000 nm, (2) approach speed: 30 nm / s, (3) harmonic amplitude: 1 nm, (4) harmonic frequency: 75 Hz, (5) depth setpoint: 200 nm, and (6) contact stiffness setpoint: 200 N / m. In some cases, the test may need to be continued beyond the 200 nm setpoint if steady state is not reached.

[0084] Suitable materials for the base layer 104 can have a hardness in the range of 1 to 2,000 MPa, or 2 to 1,000 MPa, or 4 to 500 MPa, or 5 to 100 MPa, or 5 to 30 MPa. This hardness testing is performed using the indentation testing method described above.

[0085] In at least one embodiment, the base layer 104 may be formed from a coated paper or polymeric material that is a continuous impermeable substrate, e.g., a continuous impermeable substrate refers to a structure that does not have any tears or gaps prior to slitting, and generally does not include uncoated woven or nonwoven substrates.

[0086] Preferably, base layer 104 has a generally uniform thickness across its major surface. Base layer 104 may have an average thickness of at least 50 μm, at least 60 μm, at least 70 μm, at least 90 μm, at least 100 μm, or at least 120 μm. As an upper limit, the average thickness may be up to 300 μm, or up to 150 μm.

[0087] To improve adhesion between the base layer 104 and its adjacent layers, the base layer 104 may be chemically primed or subjected to other surface treatments (e.g., corona treatment, UV treatment, electron beam treatment, flame treatment, or surface roughening treatment). For example, embodiments of the present disclosure include a configuration in which a resilient primer / make layer is disposed on the base layer 104, which is then overlaid with a conventional coated abrasive formulation in the functional layer 102. In one embodiment of the present disclosure, this continuous resilient primer layer prevents abrasive particles in the functional layer 102 from shedding (shelling) during the pulling process.

[0088] The base layer 104 may optionally be provided with an adhesive layer 106, which may be used to attach the adhesive layer 108. For example, the adhesive layer 106 may be any moisture-curing adhesive. In one embodiment, the adhesive layer 106 is used as a spray adhesive, allowing the fabric to cover the opening while remaining breathable enough to allow dust to ventilate from the front side. The use of a moisture-curing polyurethane adhesive with a starve dye or gravure coat is considered preferable for achieving this lamination. The adhesive should become non-tacky during the cooling, drying, or curing process to prevent dust from adhering and clogging the loop fabric.

[0089] Adhesive layer 108 may be a layer used to attach abrasive article 101 to an abrasive tool. In at least one embodiment, adhesive layer 108 may be a woven loop structure that corresponds to a hook-and-loop system. In one embodiment, adhesive layer 108 may be adhesive layer 106. For example, adhesive layer 108 may include a pressure-sensitive adhesive for attaching abrasive article 101 to a separate back-up pad, similar to adhesive film abrasives sold commercially under the trademark "Stikit."

[0090] In one embodiment, adhesive layer 108 may be an adhesive for attaching abrasive article 101 to a substrate. In one embodiment, the substrate may be foam (e.g., a sanding block) or may be another abrasive sheet 101, thereby forming a dual-layer abrasive article.

[0091] The abrasive article 101 may have a first surface 110 and a second surface 112. For example, the first surface 110 may correspond to the functional layer 102, and the second surface 112 may correspond to the adhesive layer 108.

[0092] In some embodiments, the functional layer 102 may cover about 40% or less, about 50% or less, about 60% or less, about 70% or less, about 80% or less, about 90% or less, 95% or less, or about 98% or less of the area of ​​the first major surface of the adhesive layer 108. In other embodiments, the functional layer 102 may cover about 50%-98%, 50%-95%, 50%-90%, 50%-85%, 50%-80%, 60%-98%, 60%-95%, 60%-90%, 60%-85%, 60%-80%, 70%-98%, 70%-95%, 70%-90%, 70%-85%, or 70%-80% of the area of ​​the first major surface of the adhesive layer 108. In one example, as shown in Figure 1, even if the end of adhesive layer 106 is approximately aligned with the end of adhesive layer 108, the presence of voids may result in a configuration in which the third major surface of functional layer 102 covers only 98% or less of the first major surface of adhesive layer 108.

[0093] 2, slit abrasive sheet 200 shows an example of a configuration in which adhesive layer-containing abrasive article 101 is slit together with adhesive layer 108. For example, adhesive layer 108 has multiple slits (e.g., slits 202 and 204) formed therein, and the multiple slits may include any one of these slits or a combination thereof.

[0094] In at least one embodiment, a slit-processed abrasive sheet may be manufactured without adhesive layer 108, and then laminated to adhesive layer 108 in a separate process. For example, a process may be performed in which patterned slits are formed in an abrasive sheet without adhesive layer 108, and then laminated to adhesive layer 108.

[0095] 2, the slitted polishing sheet 200 has slits 202 and 204 extending along the first surface 110. In one embodiment, the slits 202 extend through the functional layer 102, the base layer 104, the optional adhesive layer 106, and may also extend at least partially through the adhesive layer 108. For example, the slits 202 may extend at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the depth of the adhesive layer 108, but may not extend completely through.

[0096] In one embodiment, the slits 204 may extend completely through the entire slitted polishing sheet 200, including the adhesive layer 108. For example, the slits 204 may extend all the way through the functional layer 102, the base layer 104, the adhesive layer 106, and the adhesive layer 108, from the first surface 110 to the second surface 112. By way of example, the slitted polishing sheet 200 has a plurality of evenly spaced slits that extend across most or nearly the entire first major surface 110.

[0097] The slits preferably have a maximum width of substantially zero or close to zero when the slitted abrasive sheet 200 is in a relaxed state, although a finite width is shown in Figure 2 for clarity. Each slit has a corresponding pair of substantially continuous slit surfaces that may meet throughout the entire depth of the slit (as in slit 204), midway through the depth, or at the bottom (deepest) portion of the slit (as in slit 202).

[0098] Placing multiple slits in the slitted abrasive sheet 200, compared to punching holes, is advantageous from a manufacturing standpoint because burrs and other debris do not need to be removed when converting a precursor abrasive article (e.g., abrasive sheet 101) into a slitted article. The slits 230 may be formed by mechanically cutting the first surface 110 and / or the second surface 112 of the abrasive sheet 101 using a blade or by laser conversion.

[0099] In at least one embodiment, the slits (not shown) may only extend through at least a portion of the functional layer 102 and the base layer 104. In one embodiment, the slits may extend entirely through the base layer 104 but not through the adhesive layer 106 or the adhesive layer 108.

[0100] 3 shows another view of the slit 204. The slit 204 may have multiple slit dimensions, such as a dimension 302 along the lateral direction 304. The slit 204 may have at least two edges 306, 308 formed on each side of the slit. In a relaxed state, the edges 306, 308 of the slit 204 may contact one another. In one embodiment, there may be multiple edges on the slitted abrasive sheet 200. In one embodiment, the edges 306, 308 may form open strands of the abrasive sheet when the slitted abrasive sheet 200 is under stress.

[0101] In Figure 4, an apertured abrasive sheet 400 is shown to be formed when a tensile force is applied in at least one direction (e.g., machine direction 406 is shown). This tensile force opens the slits 204 shown in Figure 3, forming apertures 402. The apertures 402 are formed from edges 306, 308 of the slits 204. In one embodiment, the apertures 402 may be diamond-shaped or vicica piscis (fish-shaped). For example, the apertures 402 may have a major diagonal 404 and a minor diagonal 408, both of which may be smaller than the dimensions 302.

[0102] The dimensions of the aperture 402 may define an open area 414 of the aperture 402. The open area 414 may vary depending on the conditions of the manufacturing process. For example, the open area 414 may vary from a stressed open area (which may be the maximum open area) to a fixed open area to an unstressed open area.

[0103] In one embodiment, the unstressed open area may be 40% or less, 30% or less, 20% or less, 15% or less, 10% or less, or 5% or less of the stressed open area.

[0104] In one embodiment, the fixed open area may be at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, or 90% of the stressed open area.

[0105] In one embodiment, the fixed open area may be at least 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, 100%, or 150% greater than the open area in the unstressed state.

[0106] In one embodiment, the fixed open area may be at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 times the open area in the unstressed state in the same abrasive sheet.

[0107] In one embodiment, the apertured polishing sheet 400 may be formed in a skip slit or staggered pattern such that the diagonal 408 in the machine direction 406 of an aperture 402 in one row 410 does not coincide with the diagonal of another aperture in an adjacent row 412.

[0108] In one embodiment, edges 306, 308 may be formed adjacent to slit 204 of the plurality of slits.

[0109] In one embodiment, the pattern of slits may be arranged so that when tensioned to the flattening strain threshold, no more than 15%, 10%, or 5% of the surface area of ​​the edges of the abrasive sheet protrudes from the surface of the abrasive sheet. Thus, tensioning may result in a "twist" in which a portion of the edge protrudes out of the plane, but not necessarily a "foldover," because the lamination or flattening process may flatten out any twists that do not protrude significantly. Thus, in one embodiment, when strained to the flattening strain threshold, at least one twist occurs in the strands of the open abrasive sheet, but lamination does not result in any foldovers.

[0110] In one embodiment, the edges 306, 308 of the slits 204 (which are also strands) do not protrude beyond the plane of the abrasive sheet when stretched or strained to the flattening strain threshold. Thus, in one embodiment, no kinks or folds form when the slitted or apertured abrasive sheet is strained to the flattening strain threshold.

[0111] 5A and 5B show a skip-slit pattern consisting of multiple slits. While the illustrated slits extend in the cross direction, those skilled in the art will recognize that multiple slits may be arranged to extend in the machine direction, thereby allowing the slitted abrasive sheet to be expandable by cross-directional tension. As shown in FIG. 5A, abrasive sheet 84a (corresponding to slitted abrasive sheet 200) has multiple openings 86 formed therethrough in the thickness direction. These openings 86 are formed by rolling up abrasive sheet 84 and widening slits 6 using the apparatus shown in FIG. 7. The openings 86 appear on a first surface 83c of functional layer 83.

[0112] The openings 86 have a slit shape extending along the first direction D1. Specifically, the openings 86 may have an oval, a visca pisces, or a generally rectangular shape, including a diamond shape, because the openings 86 are originally formed as slits and then expanded to form the slits 6. The openings 86 have end portions 86a at both ends in the first direction D1. The end portions 86a correspond to both ends of the slits 6 in the first direction D1 before expansion. The openings 86 are arranged at a predetermined pitch in the first direction D1 and also at a predetermined pitch in a second direction D2 perpendicular to the first direction D1. In this embodiment, the first direction D1 is an axial direction corresponding to the central axis CL extending in the transverse direction. In one embodiment, the formed openings may have a random configuration. For example, variations in tension in the transverse direction and the machine direction may produce openings 86 with random shapes and orientations.

[0113] The second direction D2 corresponds to the winding direction or machine direction, which is the direction in which the abrasive sheet is wound.

[0114] The polishing sheet 84 constituting the functional layer 83 extends along the first direction D1 and can be divided into multiple regions 3 arranged in the second direction. A boundary 4 extending along the first direction D1 is formed between each pair of regions 3. FIG. 5B shows a virtual line corresponding to part of the boundary 4. When viewed from the side, the boundary 4 is a straight line extending straight along the first direction D1. The boundary 4 is a reference line set to pass through the center position and end 86a of each of the multiple openings 86 aligned at a predetermined pitch in the first direction D1. However, the position of the end 86a may be shifted due to manufacturing errors, and the virtual line of the boundary 4 does not need to perfectly coincide with the end 86a.

[0115] As described above, when an imaginary line passing through the center positions of the multiple openings 86 is set so that they are aligned along the first direction, the imaginary line corresponds to a "boundary." Furthermore, a "region" refers to a portion virtually separated by a boundary 4 and another adjacent boundary 4. When the abrasive sheet 84 is not wound up, the boundary 4 is defined by an imaginary line passing through the linear slit 6, as shown in FIG. 5B. Region 3 is set as a region in the extension direction of the abrasive sheet 84 where no slit 6 is formed.

[0116] As described above, the boundary 4 is set based on the openings 86 aligned along the first direction D1. Therefore, the multiple openings 86 are formed extending in the first direction along the boundary 4. At the boundary 4, the openings 86 are spaced apart from one another in the first direction D1. The positions at which these openings 86 are spaced apart can function as connecting portions 7 that connect the regions 3 to one another. Therefore, a pair of regions 3 adjacent to one another in the second direction D2 are connected to one another by connecting portions 7 (or bridge regions) formed between the openings 86.

[0117] Specifically, the "connecting portion" corresponds to a portion on the imaginary line on the boundary 4 where no opening 86 is formed. In this specification, the "connecting portion" may also be referred to as a "bridge region." The connecting portion 7 is a portion that does not open like the opening 86 when a force is applied to each region 3 to expand in the second direction, and connects adjacent regions 3 so that they do not separate.

[0118] In one embodiment, the space between the openings 86 in the diagonal direction may be referred to as a "strand." Thus, a strand 5 may be the region from the midpoint of a connector 7 to the midpoint of a diagonal connector 7 on a different row or boundary 4. In one embodiment, a strand 5 may be formed from an edge adjacent to a slit located between rows in the machine direction, and a connector 7 may be formed from a portion between slits in the same row in the first direction D1.

[0119] The openings 86 on the boundary 4 formed on one side in the second direction D2 and the openings 86 on the boundary 4 formed on the other side are arranged at different positions in the first direction D1. Specifically, between adjacent boundaries 4, the openings 86 on one boundary and the openings 86 on the other boundary 4 are in a staggered arrangement. Therefore, a configuration in which a plurality of openings 86 (slits 6 before winding) are arranged in a staggered manner is also called a "skip slit." In this embodiment, the openings 86 and the boundary 4 are arranged at the same position, with adjacent boundaries 4 being spaced apart. In other words, a pair of boundaries 4 are set so that the openings 86 are arranged in a staggered arrangement.

[0120] The dimensions of the region 3, opening 86, and connecting portion 7 configured as described above are not particularly limited, and may be set as follows, for example: The dimension of the region 3 in the second direction D2 may be 1 to 100 mm, or 5 to 50 mm. The dimension of the opening 86 in the first direction D1 may be 1 to 100 mm, or 5 to 50 mm. The dimension of the connecting portion 7 in the first direction D1 may be 1 to 100 mm, or 5 to 50 mm.

[0121] 6 shows a flow chart of a method 600 for manufacturing a mesh abrasive article. Reference is also made to the apparatus shown in FIG.

[0122] In block 602, an abrasive sheet is provided. As mentioned above, the abrasive sheet may be commercially available from 3M, including an adhesive layer. The abrasive sheet may be provided in a jumbo roll, and either block 604, block 606, or block 614 may be performed.

[0123] At block 604, a plurality of slits may be formed through the thickness of the abrasive sheet. At block 604, a slitted abrasive sheet having a plurality of staggered (i.e., skip slit) slits is provided, as shown in FIG. 5B. In one embodiment, the slitted abrasive sheet may be formed into a roll and processed further or continuously in a roll-to-roll manufacturing process.

[0124] As previously mentioned, the substrate may include a plurality of cuts or slits arranged in a pattern, which in some embodiments may be random and in other embodiments may be arranged along at least one axis. The two-dimensional surface of the substrate is typically viewed as having two major, orthogonal axes (x and y). For purposes of film manufacturing, the x-axis is often referred to as the "machine direction (MD)" and the orthogonal y-axis is referred to as the "cross-direction (CD)." In one embodiment, the slits may be aligned along the machine direction, meaning that the lengths of the slits are aligned in the machine direction of the substrate. In another embodiment, the slits may be aligned in the cross-direction.

[0125] The multiple slits arranged in a pattern are "gaps," but when the substrate is in an unstressed state, these gaps are substantially invisible to the naked eye. At least some of the gaps become visible to the naked eye when the abrasive article is in a stressed state. As used herein, "stressed state" includes tension, bending, or a combination thereof. Because slits are very thin (i.e., have virtually no width in an unstressed state), they are typically described by their length and depth. Typically, the incisions penetrate the entire thickness of the substrate, so their depth is the same as the thickness of the substrate. The "aspect ratio" is a parameter that indicates the relationship between the length and width of the incisions. While the term "aspect ratio" is typically used for particles, it is used herein to describe the size of holes or void regions where no material is present. In some embodiments, the aspect ratio (length / width ratio) of the slits exceeds 1000. When stress is applied, this aspect ratio decreases. An example of a suitable incision is one that is 1 cm long and 5 μm wide.

[0126] In some embodiments, at least some of the slits may be "continuous slits," meaning that the cuts extend across the surface. These slits, when stressed, become gaps that separate the backing layer from end to end, essentially dividing the backing layer in two.

[0127] The slits may have shapes more complex than the simple linear shapes described above. The slits may have a variety of two-dimensional shapes, such as crosses, asterisks, waves, chevrons, letters, numbers, etc.

[0128] In some embodiments, the slits are arranged in a pattern along the machine direction of the substrate. Often, the slits are formed using a technique known as "skip slitting." This method creates a linear array of discontinuous slits in the substrate. As the array of slits is traced across the surface, a slit appears, ends, is replaced by a non-slit area, then appears again, ends, is replaced by a non-slit area, and so on. Such patterns are described in International Patent Publication WO 19 / 043621. In these patterns, the area between the end of one slit and the beginning of the next slit is called the "bridge area." While various patterns are possible, in some embodiments, a 50% offset pattern is used. This means that when there are two linear arrays in the machine direction, the bridge areas of one array correspond to the slits of the other array, and vice versa, when viewed crosswise. Further examples of skip slit patterns are described in U.S. Provisional Application No. 62 / 952,789.

[0129] The strands of a slitted abrasive sheet having a skip slit pattern (such as the slits having a skip slit pattern as shown in FIGS. 5A-5B) may include discontinuous slits interrupted by bridge regions. Initially, the strands and discontinuous slits extend in a first direction to form a surface, are connected to each other by non-slit bridge regions extending in the first direction, and are staggered in a second direction.

[0130] The thickness of the skip-slit sheet, and therefore the thickness of the strands, may be up to about 1 mm. In some embodiments, the thickness of the skip-slit sheet or strands may be up to about 400 μm, 250 μm, 150 μm, or 100 μm. In other embodiments, the thickness may range from about 30 to 225 μm, about 50 to 200 μm, or about 100 to 150 μm.

[0131] The bridge regions in the skip-slit sheet may be at least 0.5 mm, 0.75 mm, or 1 mm in length in the particular direction in which the slits are interrupted.

[0132] Spreading may be performed to increase the width (e.g., cross-direction, or CD) of the skip-slit sheet to prevent strands from twisting and folding out of plane and causing foldover after lamination. Increasing the width of the skip-slit sheet by at least 5% may be sufficient, depending on factors such as the sheet's base layer composition, thickness, length of the discontinuous slits, length of the bridge regions, and inter-slit distance. In some embodiments, the sheet width may be increased by at least 10%, 15%, 20%, 25%, 30%, 40%, or 50%. The width of the skip-slit sheet may be increased by 100% or more depending on the conditions.

[0133] In some embodiments, the slits may be arranged in a pattern along one or more axes, meaning that the length of at least some of the slits does not coincide with the machine direction of the substrate, but is arranged at an angle of up to 90°. Slits that are 90° offset from the machine direction (MD) of the substrate are considered to be arranged along the cross direction (CD).

[0134] The slits may be formed in a variety of ways, so long as they do not substantially remove material from the substrate, and the slits are barely visible to the naked eye in an unstressed state and partially visible to the naked eye in a stressed state. These methods include introducing the slits while the substrate is being formed, such as by extrusion, molding, or machining. Alternatively, the slits may be introduced after the substrate is formed by cutting with a cutting tool, such as a knife, straight blade, rotary die blade, water jet, or laser beam, or a punching tool. In some embodiments, the substrate may be fed into a nip having a rotary die blade and anvil, where a die cuts the substrate to form the pattern.

[0135] Conceptually, a slit is a cut into a material with minimal thickness. In practice, processing techniques may involve material removal or the creation of a gap between the edges of the slit. Many cutting techniques result in a "kerf," or physical cut. For example, laser cutters ablate the material to create the slit, routers remove material, and crush cuts create a physical gap by deforming the edges of the material. Forming techniques require material to remain between the opposing surfaces of the slit, resulting in a gap or kerf in the slit. Typically, the kerf or gap in the slit is smaller than the material thickness. For example, when creating a slit pattern in paper that is 0.007 inches (approximately 178 μm) thick, the slit gap may be approximately 0.007 inches (178 μm) or less. However, gaps much larger than the thickness of the substrate may also result. As mentioned above, the slits are formed in the backing layer in a manner that minimizes material removal, so that in a stress-free state, the slits are not visible and do not form permanent openings.

[0136] In one embodiment, the ratio of height difference (unevenness) to material thickness falls within a certain range. For example, the ratio may be 0.6 or less, 0.7 or less, 0.8 or less, 0.9 or less, 1.10 or less, 1.2 or less, 1.3 or less, 1.4 or less, 1.5 or less, 1.6 or less, or 1.7 or less, as measured by a topographical profile method. In one embodiment, the ratio may be in the range of 0.6 to 1.7.

[0137] In block 606, after the slitting process has formed the plurality of slits, the slitted abrasive sheet may be tensioned (i.e., placed under stress) to form an apertured abrasive sheet. In at least one embodiment, "tensioning" refers to stretching or straining the slitted abrasive sheet, and the term "straining" may be used synonymously with "tensioning."

[0138] In one embodiment, tensioning may be accomplished by winding one end of the slitted abrasive sheet multiple times around an axially extending core member. This winding applies strain to the slitted abrasive sheet up to a flattening strain threshold. Alternatively, tensioning may be performed in the transverse direction to impart stress to the slitted abrasive sheet in a direction cross-machine. Winding may be performed in the machine direction, where the tension applied to the slitted abrasive sheet causes plastic and / or elastic deformation of the slitted abrasive sheet, transforming the slits into openings (as depicted in FIGS. 4 and 5A).

[0139] In one embodiment, the flattening strain threshold depends on the material and slit pattern used. For example, in a skip slit configuration, a force on the order of 1 pound per square inch (PSI) (6.8 kPa) can open the slit. In another embodiment, 5 PSI (34.4 kPa) or 50 PSI (68 kPa) may be sufficient to fully open the slit and form a stressed open area.

[0140] In one embodiment, the flattening strain threshold is reached at the point where the maximum open area is achieved in the apertured abrasive sheet without folding over after lamination. For example, if the maximum open area is 35% but the mesh abrasive article folds over, the flattening strain threshold is exceeded.

[0141] In one embodiment, the tensioning may be accomplished using a tentering process, in which a pair of clips secures opposite sides of a slitted abrasive sheet and moves in opposite directions to open the slits and form a plurality of apertures with stressed open areas.

[0142] In one embodiment, the tensioning at block 606 may be accomplished by a web transport process in which the slitted abrasive sheet is accelerated by controlling the relative speeds of adjacent nip or pulling rolls to create tension between two points on the abrasive sheet. The web transport process may also be used in conjunction with the winding process described herein.

[0143] In one embodiment, block 606 may be performed at a heated stretching temperature. For example, when forming multiple apertures with stressed aperture areas, stretching may be performed at temperatures above room temperature to obtain larger apertures. In one embodiment, the heating temperature may be above the maximum glass transition temperature of the substrate. For example, the stretching temperature may be at least 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, or 120°C.

[0144] As illustrated in FIG. 7, a step of winding an abrasive sheet 84 multiple times around an axially extending core member 82 is performed. For example, dry winding is performed using a winding device 50 shown in FIG. 7. The winding device 50 includes a member for holding a roll 51 of the abrasive sheet 84 having a slit 6 formed therein. The winding device 50 supplies the abrasive sheet 84 from the roll 51 and guides it via multiple rollers to a winding section 52. The winding section 52 winds the abrasive sheet 84 multiple times around the core member 82 to form a roll 54. At this time, the abrasive sheet 84 is wound under tension such that the slit 6 (see FIG. 5A) is enlarged. The wound abrasive sheet 84 may be fixed to the roll 54 by a predetermined method.

[0145] The tension may be set by a tensioner 704 applied to the abrasive sheet 84. For example, the tensioner 704 (in combination with the winding of the core member 12) may move up and down relative to other components to apply tension to the abrasive sheet 84. In one embodiment, the tension may be measured between any two points on the abrasive sheet within region 706 (e.g., after it has been released from the roll 51 and before the adhesive layer is fixed or applied). Thus, multiple openings are formed from the multiple slits, forming an apertured abrasive sheet in region 706. As the abrasive sheet 84 is further stretched, the multiple openings may become larger, and the maximum aperture ratio may be achieved from the boundaries of the multiple slits.

[0146] In one embodiment, the open area of ​​one or more of the apertures may be a stressed open area when tension is applied to the slit abrasive sheet near the roll 51 (region 710). When tension is reduced or removed (prior to the clamping step), the stressed open area may shrink back to an unstressed open area near the roll 51 (clamping region 710).

[0147] At block 608, the apertured abrasive sheet formed at block 606 may be subjected to a fixation process to fix the plurality of apertures. For example, the fixation process at block 608 may be performed on the apertured abrasive sheet such that at least a portion of the plurality of apertures retain at least 10% of their stressed open area in the unstressed state. After the fixation process at block 608, the apertured abrasive sheet becomes a mesh abrasive article.

[0148] The fixation process may include various process steps, such as blocks 610, 612, and 614, which are not exhaustive. Block 608 may include any combination of blocks 610, 612, and 614. For example, the fixation process may include applying both heat and pressure using one or more components of the manufacturing equipment (e.g., winding apparatus 50).

[0149] Heat may be applied to the apertured abrasive sheet at block 610 to relieve elastic deformation within the apertured abrasive sheet. In one embodiment, the heating is performed by an in-line oven 708, which may partially fix / hold at least a portion of the plurality of apertures as the stressed aperture areas return to fixed aperture areas.

[0150] In one embodiment, the heating may be performed with forced hot air. In one embodiment, the heating temperature may be at least 100° C., 110° C., and 120° C. The application of heat to the apertured abrasive sheet in block 610 may be performed separately from the high temperature stretching condition in block 606 described herein.

[0151] At block 614, the reel device 50 may apply pressure to the apertured abrasive sheet to form a mesh abrasive article.

[0152] In one embodiment, pressure may be applied using at least one roller (e.g., roll nip 702), which applies heat and / or pressure (e.g., a heated roller) to the apertured abrasive sheet, and can secure the apertures by elastic forces to prevent them from returning to their slits.

[0153] In one embodiment, pressure may be applied using two flat platens.

[0154] In one embodiment, the pressure applied may be at least 0.1 MPa, 1.5 MPa, 2.0 MPa, or 2.5 MPa.

[0155] 7 shows only one set of roll nips 702, any number of roll nips 702 may be used. Depending on the line speed of the abrasive sheet 84, the abrasive sheet 84 may be exposed to heat and / or pressure for up to 10 seconds, 30 seconds, 45 seconds, or 1 minute. In one embodiment, the apertured abrasive sheet may be flat-pressed to fix the apertures.

[0156] The securing process may also include applying a carrier liner to the non-functional side of the apertured abrasive sheet, as shown in block 614. The carrier liner may provide an additional surface for securing the apertures. Carrier liners may be available from 3M Company, St. Paul, Minnesota, USA, under the trademark "602197 PET FILM."

[0157] In one embodiment, one or more of blocks 610, 612, and 614 may be performed simultaneously or in parallel within method 600. In one embodiment, heat may be applied simultaneously with the pressure and / or carrier liner. For example, the abrasive sheet 84 may be cooled and wound onto the roll 54. In one embodiment, the pressed abrasive sheet may be quenched at a temperature below the glass transition temperature of the substrate to freeze the stressed configuration.

[0158] In block 615, the abrasive sheet may be attached to the adhesive layer. In one embodiment, the base layer of the pre-slit abrasive sheet may be attached to the adhesive layer before being slit in block 604. In block 615, bonding may be performed by laminating the apertured abrasive sheet to the adhesive layer (e.g., hook-and-loop fastener). Lamination refers to the process of joining two or more layers of material (e.g., the apertured abrasive sheet and the adhesive layer) using heat, pressure, or adhesives, as further described herein. In one embodiment, the base layer of the apertured abrasive sheet may be laminated directly to the adhesive layer (without an intermediate layer such as a release liner).

[0159] The process of laminating a functional layer to an adhesive layer typically begins with preparation of both layers. For example, the adhesive layer may be a pressure-sensitive adhesive, a hook-and-loop fastener material, or other mechanical fastening means. The two layers are aligned and pressed together using a lamination device, which may apply heat and pressure to the functional layer and adhesive layer, similar to block 608. For example, the applied pressure may be less than 1 MPa, e.g., 0.1 MPa or greater. While the lamination process is not shown in FIG. 7, a sheet of adhesive layer may be provided just prior to line oven 708.

[0160] The lamination process may be accomplished using a variety of techniques, including hot melt adhesives, solvent-based adhesives, water-based adhesives, etc. Additionally, variations in the lamination process may include the use of a release liner to facilitate handling and storage of the abrasive sheet prior to use.

[0161] The adhesive layer may be breathable. For example, the final mesh abrasive article or adhesive layer may have a breathability of greater than 100, 200, 300, or 377 cubic feet per minute per square foot, as measured according to ASTM D737-18(2023). The adhesive layer may be a mesh or netting support. Mesh supports may be distinguished from other woven fabrics by the size of the holes formed therein. In at least one embodiment, the holes in the mesh support are formed by the yarns (if knitted or woven) or by the polymer warp and weft (if extruded). In knitted fabrics, the hole size may vary. In at least one embodiment, the mesh support 102 may have an average open area of ​​0.5 square millimeters. The open area may be at least 20%, 30%, 40%, 45%, 50%, or 60% or more. The initial open area may be between 40% and 60% (inclusive).

[0162] In at least one embodiment, the mesh support may include a sizing agent.

[0163] When the mesh support is a fabric (woven, nonwoven, or knitted), the fabric may have the following properties: Various fabric-like mesh supports are commercially available from Sitip SpA (Cene, Italy) or Scott and Fyfe Ltd. (Tayport, UK).

[0164] In at least one embodiment, the mesh support yarn thickness may be at least 100 μm, 150 μm, 300 μm, or 350 μm. On other scales, the yarn total denier may be up to 3000 denier, 1000 denier, or 500 denier. In at least one embodiment, the yarn breaking strength may be at least 300 mN / tex as measured by ASTM D2256. The mesh support may also have a fabric weight of up to 300 g / m. 2 , 220g / m 2 , or 120 g / m 2 and may be at least 40 g / m 2 may be.

[0165] In at least one embodiment, the mesh support is substantially flat, and flatness may be defined using the Kawabata rating system for surface friction and roughness. Thus, in some embodiments, the adhesive layer is flat and planar. In mesh fabrics, such as knitted fabrics, "flat" or "planar" refers to a fabric surface that lacks noticeable bumps, bulges, or ripples, or that is not designed to conform to the contours of the body. Flatness in this context is achieved when the yarns that make up the mesh fabric are uniformly distributed, without waviness or thickness variations. This property is a desirable quality in many types of mesh fabrics because it provides a smooth appearance and uniform texture.

[0166] In at least one embodiment, a plane may be defined based on a single plane containing the majority of the surface or cross-sectional area of ​​a yarn or other material. For example, if 50% of the solid surface area of ​​a fabric lies in a first plane and 30% in a second plane, the first plane is considered the reference plane. Thus, loops (if knitted) may be elevated relative to the reference plane. The reference plane may be generally parallel to a flat surface on which the mesh support rests. In at least one embodiment, the plane of a woven fabric may be defined by the weft.

[0167] In one embodiment, lamination at block 615 may include applying an adhesive to the base layer or adhesive layer and applying pressure or heat to the base layer or adhesive layer.

[0168] At block 616, the reel 50 may further cut / package the abrasive sheet 84. Additional processing at block 616 may include converting, such as cutting the roll 54 into smaller units. For example, the mesh abrasive article may be cut in the cross direction (CD) and / or machine direction (MD) to form various shapes.

[0169] Figures 8-24 show various slit patterns, with "A" showing the film in a slit and unstressed / unreticulated state and "B" showing the same film pattern in a stressed / reticulated state. References to figure numbers include either Figure A or Figure B unless otherwise specified.

[0170] 8, 9, 10, 13, 15, 16, 17, and 19 show a reticulated abrasive article 10 having a length and a width direction, comprising a plurality of strands 16 of abrasive material connected to one another at bridges or connecting regions 18 in the abrasive material and separable between the connecting regions 18 to form openings 22 in the abrasive material, which provide variably expandable regions. Each opening 22 has a length dimension 12 and a width dimension 14, and each strand 16 has a thickness 15. The reticulated abrasive article 10 is expandable in at least one direction. In some embodiments, the direction of expansion is lengthwise, i.e., expansion occurs along an axis parallel to the lengthwise dimension 12 of the reticulated abrasive article 10. In other embodiments, the direction of expansion is widthwise, i.e., expansion occurs along an axis parallel to the widthwise dimension 14.

[0171] In some embodiments, the openings 22 are longer in the machine direction 12 than they are in the width direction. For example, in the embodiments shown in Figures 8, 9, and 17, the openings 22 are diamond-shaped. In the embodiments shown in Figures 10, 13, 15, 16, and 19, the openings have a shape other than a diamond. As shown in Figures 8-10, 13, and 15-17, the screen abrasive article 10 has slits 11 or perforations of one size that form the openings 22.

[0172] In one embodiment, Figures 8 and 9 are considered "simple slits," which is defined as a slit that has exactly two ends.

[0173] 11-14 and 19-20, in some embodiments, the screen abrasive article 10 disclosed herein provides two sets of apertures for more complex expandability. For example, as shown in Figure 14A, the screen abrasive article 10 is provided with two slits 11, 31 or perforations of different sizes, thereby forming the apertures 22, 16 shown in Figure 14B.

[0174] 12, 14, and 18, in some embodiments, the screen abrasive sheet 10 disclosed herein provides two or more sets of apertures for more complex scalability. For example, as shown in Figures 12A, 14A, and 18A, the screen abrasive sheet 10 is provided with slits 11, 21, 31 or perforations of multiple sizes or shapes, thereby forming the apertures 22, 23 shown in Figures 12B, 14B, and 18B.

[0175] In some embodiments, the screen abrasive sheet 10 may be described in terms of the relationship of the slits to one another before and after stretching. Unless otherwise specified, slit overlap refers to the degree of overlap measured at least before stretching (i.e., in the pre-stretched state). Specifically, it refers to whether the slits are offset relative to an axis perpendicular to the longitudinal dimension 12 (or an axis perpendicular to the width direction).

[0176] In at least one embodiment, the polishing sheet 10 shown in FIG. 12 may have a multi-slit pattern. As used herein, a "multi-slit pattern" refers to a pattern of individual slits forming a first row of adjacent slits along the transverse (i.e., cross) direction, with each slit in the first row aligned in the transverse direction. In a multi-slit pattern, the first adjacent row of slits forms a repeating pattern with at least a second row along the axial (i.e., machine) direction of the sheet, with the slits in the first row offset laterally from the slits in the second row. A "multi-slit pattern" can include, for example, double-slit, triple-slit, and quadruple-slit patterns.

[0177] Figure 16A shows a pattern featuring a single slit pattern with sinusoidal skip slits. For example, the midpoint of each slit is approximately aligned with the space between two adjacent slits in different rows. When opened, this pattern has the advantage of exhibiting high flatness when the slitted abrasive sheet is stretched to the flattening strain threshold, as shown in Figure 16B. A "wavy pattern" is a two-dimensional slit pattern with alternating peaks and valleys, which may be regular or irregular. A "sinusoidal pattern" refers to a smooth, periodic pattern with alternating peaks and valleys centered around a baseline.

[0178] In other embodiments, at least some of the slits may be "compound slits," which are slits with more than two ends. In FIG. 23, imaginary lines extend between and connect these ends. In this embodiment, the imaginary line connecting the ends of a first slit is substantially collinear with the imaginary line connecting the ends of an adjacent slit. In this example, all of the imaginary lines between the slit ends in each row are generally collinear. However, the region between the ends of each slit is not collinear with the imaginary line connecting the respective slit ends.

[0179] Referring to Figures 21-24, in some embodiments, the screen abrasive article 100 is expandable in multiple directions.

[0180] In some embodiments, the screen abrasive article 100 has a length direction and a width direction and includes multiple regions 116 of abrasive material that are separable from one another to form openings 122 in the abrasive material. Each opening 122 has a length direction dimension 112 and a width direction dimension 114, such that the screen abrasive article 100 is expandable in at least two directions.

[0181] In some embodiments, the article 100 disclosed herein may further include a collection 124 of multiple regions 116 radiating from a common intersection 125. In some embodiments, the disclosed article 100 provides a first abrasive brightness when the multiple regions 116 of abrasive material 20 are separated by a first width dimension, and a second reflective brightness when the multiple regions 116 of reflective material 20 are separated by a second width dimension.

[0182] In some embodiments, the slits 11, 21, 31, perforations, or combinations thereof may be made using known techniques such as rotary die cutting, laser cutting, ultrasonic slitting, and the like.

[0183] 21 and 23 show another slit configuration called a "biaxial multi-slit pattern." While the slits in previous multi-slit patterns, such as the double-slit pattern of FIG. 12, are parallel to one another, this embodiment allows some slits in the pattern to be oriented non-parallel to the other slits. In one embodiment, the polishing sheet 100 has a slit pattern in which half of the slits 121 are oriented in the machine direction and the other half, the slits 111, are oriented in the transverse (cross) direction. The slits 121 and 111 otherwise have similar characteristics to the previous multi-slit patterns.

[0184] The biaxial multi-slit pattern of Figure 21A allows the abrasive sheet to develop a three-dimensional stress state, as shown in Figure 21B, which is achieved by tensioning the abrasive sheet 100 of Figure 21A along two orthogonal tension axes, the machine direction and the cross direction.

[0185] Optionally, and as shown, the tension axes may be exactly aligned with the machine and cross directions. Tension may be applied along both tension axes simultaneously or sequentially. In some cases, pulling along a single axis is sufficient to expand the sheet, especially when that axis is oblique (e.g., 45 degrees) to both slits 121 and 111.

[0186] In some embodiments, the biaxial multi-slit patterned polishing sheet of Figure 21A or 23A is "auxetic," meaning that when stretched along one axis, it also expands in the orthogonal axis. Unfolding can also be achieved by applying tension along any combination of these two vectors, e.g., a 45° angle.

[0187] As shown in FIG. 24, at least some of the slits may be "compound slits," which are slits with more than two ends. In the current example, imaginary lines extend between and connect these ends. In this embodiment, the imaginary line connecting the ends of a first slit is substantially collinear with the imaginary line connecting the ends of an adjacent slit. In this example, all of the imaginary lines between the slit ends in each row are generally collinear. However, the region between the ends of each slit is not collinear with the imaginary lines connecting the ends within that row.

[0188] 24A shows that abrasive sheet 100 has a six-axis multi-slit pattern, with slits 131, 121, and 111 aligned in six different directions within the plane of abrasive sheet 100. Each of these directions forms a 60-degree angle between any two of the other directions. Each pattern of slits 111, 121, and 131 is aligned along a specific direction and intersects at its ends to form a repeating compound slit pattern consisting of pairs of slits at 60-degree angles to each other.

[0189] FIG. 24B shows the polishing sheet 100 partially unfolded by application of tension along the six tension axes.

[0190] [Definition] "Abrasive article" means an abrasive product that is expanded and configured to be laminated or adhered to an adhesive layer. In one embodiment, "abrasive article" refers to an intermediate product, which may exist in roll form (before being converted / cut into a finished product).

[0191] "Abrasive sheet" means an intermediate abrasive product that has not yet been slit, expanded, or adhered to an adhesive layer.

[0192] "Abrasive sheet surface" means the surface of the abrasive sheet defined by the maximum median edge height across the abrasive sheet in its unstrained state.

[0193] "Air permeable" means a material or structure that allows air or gas to pass through its surface or volume. Breathability can be quantified in various ways, such as the Gurley method.

[0194] "Continuous impermeable substrate" means a monolithic, unslit layer of material that is impermeable to air, including coated paper and polymeric films, but generally excluding uncoated nonwoven fabrics and papers. This substrate generally has a void content of less than 1% or an air permeability of less than 2 cfm / sqft per ASTM D737-18(2023).

[0195] "Cut-out" means the surface area removed from the sheet by the intersection of a slit. Note that many forming techniques may remove a portion of the surface area of ​​the sheet, but these are not considered "cut-outs" for purposes of this application.

[0196] "Different positions" means that the central positions of the connecting portions in the second direction are different from each other, and as long as they are at least partially different, they may partially overlap.

[0197] "Elastomeric" means a material that is able to return to its original shape when a deforming force is removed.

[0198] "Fixed opened area" refers to the open area of ​​the opening after the fixing process when it is not subjected to strain or tension.

[0199] "Fixing" refers to a process that converts an article into a more dimensionally stable form, such as applying heat and pressure to a slit and stressed abrasive sheet to prevent the openings from returning to their original shape when the stress or strain is removed. In some embodiments, fixing is a separate process from lamination.

[0200] "Flat" refers to the property of having a smooth, uniform surface without irregularities, undulations, wrinkles, etc. In one embodiment, flatness is defined by the uniform thickness of the functional layer excluding the abrasive particles. It can also be defined by a ratio of height difference to average thickness of less than 2, less than 1.5, or less than 1.1, as determined by the topological profile method.

[0201] "Flat compressed" means compression perpendicular to the plane of the sheet, which prevents the strands from overlapping with other abrasive sections after the slit abrasive sheet has been stretched open.

[0202] "Flattenability strain threshold" refers to the maximum strain applied along the primary tension axis at which a condition occurs. In one embodiment, this condition refers to the point at which a slit abrasive sheet can be compressed flat in a direction perpendicular to the plane of the original shape and laminated to a substrate while maintaining overall strain. In another embodiment, this condition refers to the point at which a twist in the strands occurs without causing a fold.

[0203] "Foldover" refers to an area where a portion of the polished substrate unintentionally folds over during tensioning and remains after lamination to the adhesive layer. This results in the non-polished side being exposed to the functional surface. For example, this can occur when a twist is left unflattened after lamination or heat and pressure treatment.

[0204] "Mesh abrasive article" means a continuous sheet of coated abrasive material having openings to allow dust to pass through that can be attached to the flat surface of a power sander.

[0205] "Opening" refers to the open area created by applying a tensile force to a slit. Depending on the strain state, the opening can have a stressed open area, a non-stressed open area, and a fixed open area.

[0206] "Reticulated" means a net-like structure in which strands or regions are connected at specific points.

[0207] In some embodiments, a reticulated abrasive article having a length and a width direction may be provided. The article is composed of a plurality of strands connected to each other at bridging regions and separated from each other to form apertures, which provide variably expandable regions. The abrasive material has a major functional surface and a major less functional surface, each aperture has a length and a width dimension, the strands have a thickness, and the article is expandable in at least one direction.

[0208] As used herein, expanding a reticulated abrasive article refers to varying areas of openings. Reticulated abrasive articles according to the present disclosure can be expanded in one or more directions to provide different opening ratios.

[0209] When the reticulated abrasive article is expanded, the open area ratio increases, brightness decreases, and breathability increases. In some embodiments, the reticulated abrasive article is expanded before being attached to a substrate. In other embodiments, the reticulated abrasive article is expanded by the movement of the user when worn on activewear, such as on the elbow or knee.

[0210] A "single slit pattern" is a pattern in which slits form rows across the sheet that are repeated axially along the sheet, and in which adjacent rows have different slit arrangements, e.g., the slits in a row are axially offset or out of phase.

[0211] "Skip slit" means a pattern of slits such that the midpoint of any row of slits is not aligned (along the vertical axis) with the midpoint of an adjacent row of slits.

[0212] A "slit" refers to a narrow, elongated cut or opening. A slit is defined herein as a thin, straight or curved cut with at least two ends. In one embodiment, a perforation is a specific type of slit consisting of a series of small slits. Many cutting techniques create a "kerf," or a cut with a physical width, and therefore the slit also has a width. In various forming methods, the slit gap or kerf is generally equal to or less than the material thickness.

[0213] "Strain" means the deformation of a solid caused by stress, measured as the change in length relative to the original length of the material.

[0214] "Stressed opened area" means the open area of ​​an opened abrasive sheet when it is under strain or tension.

[0215] By "stressed state" is meant a state in which the abrasive sheet is under tension along at least one axis up to the flattening strain threshold.

[0216] The "Topographical Profile Method" is a method for comparing the surface of a substrate with raised portions formed thereon, and is similar to the method described in WO2023037272.

[0217] By "twist" it is meant that the strands of the apertured abrasive sheet bend or twist out of the plane to form a curved or partial helical shape.

[0218] "Unstressed opened area" means the open area of ​​an opened abrasive sheet when it is not under strain or tension.

[0219] "Unstressed state" means that the abrasive sheet is not under tension.

[0220] [example] Test Method

[0221] Topological Profile Method

[0222] The topological profile was measured using a Keyence VKX1100 confocal 3D measurement confocal microscope (Keyence Corporation, Osaka, Japan). A 4" x 4" combined sample was placed on a sample tray and evaluated using ring and axial illumination at 2.5x magnification. Four images were taken of a 2" x 2" square area at 2.5x magnification and merged to create a single image for analysis. The resulting images were analyzed using VK Series analysis software (Keyence Corporation, Osaka, Japan). The relative height difference was calculated by determining the difference between the height of a ridge and its neighboring area and dividing the difference by the average thickness of the sample.

[0223] Abrasion test method

[0224] A 3-inch diameter disk was punched from each heat-laminated, flexible, abrasive sample. The 3-inch disk was mounted on a Festool LEX 3 77 / 2.5 sander, which was connected to a Festool CT 36 E dust collection system. The sander was supplied with compressed air and set to a dynamic air pressure of 50 psi while operating with the throttle valve fully open. Each abrasive disk was tested on an unsanded portion of an 18-inch high x 24-inch wide automotive test panel, available from ACT Test Laboratories, LLC (Hillsdale, Michigan), by manually moving the sander in a linear motion across the 18-inch vertical span of the panel for 30 seconds and applying a downward load of approximately 4 kg. The test panel was weighed before and after testing, and the difference was recorded as the "cut value."

[0225] Surface Finish Measurement

[0226] After polishing, the finish (Ra, Rz, Rz max) of each polished lane was measured at five locations using a Taylor-Hobson (Leicester, UK) S100 series profilometer and a PK-03 diamond stylus. The average of five measurements is reported for each sample.

[0227] Each sample was then visually evaluated under lighting to determine finish, scratch density, and the presence or absence of "q-ing" (irregular scratch direction).

[0228] Measurement of breathability

[0229] The permeability of the abrasive article was measured in accordance with ASTM D737-18(2023) using a Gurley 4301 Permeometer. The permeability test results are reported in cubic feet per minute per square foot (cfm / ft 2 ) A sample is considered "air permeable" if it meets the following criteria:

[0230] Foldover determination method

[0231] Foldovers occur when laser-slit samples are stretched beyond the limit of flat processing during the thermal lamination process. Foldovers occur primarily in the strands, but can also occur in bridge regions. In this case, a twist in the stretched laser-slit sample causes it to fold during lamination, exposing the unpolished side of the polished support above the polished surface. For each sample, a 3-inch diameter disk sample was observed through a 2.75 magnification lens, and the number of foldovers was manually counted.

[0232] Polishing area ratio

[0233] The % abrasive area of ​​the slit and stretched samples was calculated gravimetrically using the following formula:

[0234] % abrasive area = (B / A) × 100%,

[0235] A = Mass of the parent unstretched 3-inch abrasive disc

[0236] B = Mass of a slit and stretched 3-inch abrasive disc

[0237] The % open area is calculated as 100% - polished area: % open area = (1 - (B / A)) × 100%.

[0238] "Stretch" means the value obtained by adding 100% to the strain value.

[0239] How to calculate strain

[0240] The % strain was determined by stretching a rectangular sample (78 mm long x 152 mm wide) along the machine direction of the slit pattern and measuring the final length with a ruler. The % strain was calculated by dividing the difference between the final length and the original length of 78 mm by the original length of 78 mm.

[0241] Sample preparation

[0242] The objects and advantages of the present disclosure are further illustrated by the following non-limiting examples, although the particular materials and amounts thereof described in these examples, as well as other conditions and details, should not be construed as unduly limiting the present disclosure. The following abbreviations are used in the description of the examples: °C: Degrees Celsius cm: centimeters g / eq.: gram per equivalent g / m 2 : grams per square meter g / mol: gram per mole kg: kilograms mil: 1 / 1000 inch mm: millimeters μm: micrometer UV: Ultraviolet light W / in: Watts per inch W / cm: Watts per centimeter

[0243] Unless otherwise noted, all reagents were obtained from chemical vendors such as Sigma-Aldrich Company (St. Louis, MO, USA) or synthesized by known methods. All proportions are by weight unless otherwise noted.

[0244] Abbreviations for materials and reagents used in the examples are as follows: ACR: Trimethylolpropane triacrylate AMOX: Di-tert-amyl oxalate BKG1: Backing 1; 120g / m 2 Net mesh with a mass of 1000, manufactured by Sitip Technical Textiles (Cene, Italy) CHDM: 1,4-cyclohexanedimethanol EP1: Bisphenol A-based epichlorohydrin epoxy resin with an epoxy equivalent weight of 525-550 g / eq. and an average epoxy functionality of 2, available as "EPON 1001F" from Momentive Specialty Chemicals (Columbus, Ohio, USA). EP2: Bisphenol A epoxy resin with an epoxy equivalent weight of 185-192 g / eq. and an average epoxy functionality of 2, available from the company as "EPON 828" EP3: (3',4'-epoxycyclohexylmethyl) 3',4'-epoxycyclohexanecarboxylate ESTANE: Polyether-based thermoplastic polyurethane resin, obtained as "ESTANE 58887 NAT 021" from Lubrizol Advanced Materials (Cleveland, Ohio, USA) FLL: inorganic fine powder functional filler, obtained as "MINEX 3" from Unimin Corp (New London, Connecticut, USA) P600: P600 grain size aluminum oxide abrasive mineral, obtained from Treibacher Industrie AG as "ALODUR BFRPL" PC1: A mixture of 4-thiophenylphenyl diphenylsulfonium hexafluoroantimonate and bis[4-(diphenylsulfonio)phenyl]sulfide bis(hexafluoroantimonate) (solvent: propylene carbonate), obtained as "CPI 6976" from Aceto Corporation (Port Washington, NY, USA). PC2: 2,2-dimethoxy-2-phenylacetophenone, obtained as "IRGACURE 651" from BASF (Wyandotte, Michigan, USA). PC3:η 6 -Xylene (mixed isomers) η 5 -Cyclopentadienyl iron (1 + ) Hexafluoroantimonate (1 - ) PC4: Ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, obtained from BASF as "IRGACURE TPO-L" PEP: A high molecular weight, hydroxyl-terminated, saturated, linear, semi-crystalline copolyester with a molecular weight of 35,000 g / mol, obtained from Evonik Industries (Parsippany, NJ, USA) as "DYNAPOL 51227." PET: Polyester terephthalate film, 1.97 mil (50 μm) thick, obtained from 3M as "602197 PET FILM" PI: 2-hydroxy-2-methyl-1-phenyl-1-propanone Prop Carb: Propylene carbonate, obtained as "JEFFSOL PC" from Huntsman Corp (The Woodlands, Texas, USA) ZNST: Zinc stearate soap dispersion (39-41% by weight), obtained from eChem LTD (Leeds, UK) as "EC994C"

[0245] Preparation of make resin

[0246] A series of make resins were prepared according to the compositions listed in Table 1. AMOX, EP1, EP2, CHDM, and PEP were mixed directly into a twin-screw extruder set at temperature zones of 30, 105, 110, 100, 65, and 60°C at 300 rpm. The mixed resins were fed into a pin mixer (1750 rpm) to which ACR, PC2, PC3, PC4, and PropCarb were added directly. The output from the pin mixer was fed into a heated coating die, and the flow rate from the pin mixer was controlled to achieve the target amount of make resin on the abrasive backing.

[0247] [Table 1]

[0248] Preparation of sizing resin

[0249] Table 2 below shows the ingredients and amounts used in formulating size resins 1 and 2. Each size resin was prepared by mixing EP2, EP3, and ACR, and optionally FLL, in a container. Prior to producing abrasives, PC1 and PI were added to the premixed resin batch and homogenized by stirring at room temperature for 30 minutes.

[0250] [Table 2]

[0251] Manufacturing method of abrasive sheet

[0252] The ESTANE resin was extruded using a single screw extruder as a first thermoplastic polyurethane film having an average thickness of 5 mils (127 μm) and cast onto a 1.97 mil (50.04 μm) thick PET film. The make resin was applied to the ESTANE film at a nominal coating weight of 16.5 g / m. 2The film structure was then passed under Fusion UV Systems equipped with one set of D bulbs and one set of V bulbs operating at 600 W / in (236 W / cm). Abrasive Mineral P600 was applied to the make resin at a nominal coating weight of 28 g / m. 2 The web was then heated under an infrared heater for approximately 7 seconds at a web temperature setting of 100°C. The size resin was then roll coated onto the make layer and abrasive particles at a nominal dry coating weight of 13 g / m. 2 The coating was applied at a nominal coating weight of 9 g / m² and passed under Fusion UV Systems with one set of H bulbs and two sets of D bulbs operating at 600 W / in² (236 W / cm²). It was then passed through an infrared oven with a target outlet temperature of 125°C. 2 The mixture was applied onto the size layer and then processed in a drying oven with a target outlet temperature of 135°C.

[0253] The resulting coated abrasive web was then flexed by wrapping the abrasive sheet around a 1 / 4-inch (6.35 mm) diameter circular metal bar with the backside of the abrasive sheet in contact with the metal bar. The metal bar was positioned at a 45-degree angle relative to the web direction. The web was wrapped approximately halfway around the metal bar, with the web moving in the opposite direction before and after passing the bar. After the web passed the first metal bar, it was wrapped around a second 1 / 4-inch (6.35 mm) diameter metal bar, also positioned at a 45-degree angle, with the backside in contact with the metal bar. However, the second metal bar was positioned at a 90-degree angle relative to the first metal bar. The wrap angles around the first and second metal bars were identical, with the abrasive backside in contact with the metal bar on both sides.

[0254] The resulting coated abrasive web was kept at room temperature (ie, 20-24°C) until used in the following examples.

[0255] Lamination method onto net mesh

[0256] The PET liner was removed from the abrasive and heat-laminated to BKG1 using a SteamFast Model SF-680 iron (Vornado Air LLC, Andover, Kansas). The iron was set to the "linen" setting and heated to steady state. A 12" x 12" square of BKG1 was cut and placed with the loop side in contact with the cardboard substrate. A 7" x 7" square of abrasive was cut and placed on BKG1 with the abrasive side facing up, and the abrasive and BKG1 were pinned to the cardboard substrate. The cardboard / BKG1 / abrasive multilayer was placed cardboard-side down on the lower heated surface of the SteamFast iron. A paper release liner was placed on the abrasive surface with the release side facing down. The iron clamped the multilayer and held it in place for 1 minute and 30 seconds. The multilayer was then removed from the iron and allowed to cool at room temperature for 1 minute. After cooling, the laminated BKG1 and polishing layer were removed from the cardboard substrate.

[0257] Comparative Example C1 was prepared by cutting a 3 inch diameter disc from heat laminated flexible abrasive before it was slit as described below.

[0258] Preparation of slit polishing sheets

[0259] The PET liner laminate was removed from the abrasive and laser slit according to the pattern using an Epilogue Fusion laser (Model 13000, 75 watts, 100% speed, 70% power, 50% frequency). A 12" x 12" square of BKG1 was cut and placed with the loop side in contact with a cardboard substrate. A 6" x 6" square of the slit abrasive sheet was cut and manually stretched and pinned in tension onto BKG1, with the abrasive side facing away from BKG1. The resulting multilayer was heat laminated with an iron using the same lamination method described above.

[0260] How to determine the flattening distortion threshold

[0261] Examples EX1, EX2, and Comparative Examples C2 and C3 were prepared by cutting 3-inch diameter disks from the heat-laminated, flexible, pre-slit, polished samples. Each sample was laser-slit according to the pattern shown in FIG. 16A and prepared with different levels of applied strain, as shown in FIG. 16B. Comparative Example C3 was prepared with no applied strain (i.e., unstressed). Each stretched sample was compressed flat on a flat substrate while maintaining a nominal overall strain, and the sheet was evaluated for foldover at any point. Comparative Example C2 represents the strain at which the first foldover was observed.

[0262] The number of foldovers was counted, and the % polished area was calculated according to the test method described above. Air permeability measurements were then performed. Table 3 summarizes the samples prepared, their strain rate, polished area rate, height difference / thickness ratio (based on the topographical profile method), open area, and number of foldovers.

[0263] Comparative Example C2 was stretched to the point where one or more foldovers occurred for the 3 inch diameter sample, indicating that the flattening strain threshold had been reached.

[0264] Table 3 - Dimensions for various degrees of tension [Table 3]

[0265] Sample surface finish

[0266] The samples were subjected to abrasion tests and surface finish measurements, the results of which are summarized in Table 4. Comparative Example C4 is a commercially available product, Abranet Ace P600, manufactured by Mirka (Finland).

[0267] Table 4 - Abrasion tests and surface finish measurements [Table 4]

[0268] Thus, EX1 and EX2 are mesh abrasive articles with an air permeability greater than 377 cubic feet per minute per square foot when measured according to the Air Permeability Measurement Method described herein, and have an acceptable cosmetic finish and low total cut.

[0269] Example of P1200 particle size

[0270] A disc of commercially available 3M "Purple Finishing Film" P1200, part number 30668, was manually laminated at room temperature to the adhesive side of a 12" x 12" piece of 3M Adhesive Transfer Tape 9453LE, with the abrasive side facing away from the adhesive. A paper release liner was placed opposite the adhesive. The abrasive / adhesive / paper liner laminate was laser slit using an Epilogue Fusion Laser Model 13000 (75 watts power, 50% speed, 100% power, 50% frequency) according to the pattern shown in Figure 16A.

[0271] A 12" x 12" BKG1 sample was cut and placed on a rigid cardboard substrate with the looped surface in contact with the cardboard. The paper liner was removed from the abrasive / adhesive / paper liner sample, and one end was pinned to BKG1 on the cardboard substrate. The other end was stretched to 34% strain, as shown in Figure 16B, and pinned to BKG1 in the stretched state with the abrasive surface facing away from BKG1. The BKG1 and abrasive layer were then laminated, removed from the rigid cardboard substrate, and cut into a 3" diameter circle. An example of the P1200 grit sample has a sinusoidal pattern, as shown in Figure 25. This final product uses a P1200 grit, which is much finer than the P1000 grit mesh currently available on the market. Using the method described herein, it is possible to obtain a more precise abrasive surface in a coated abrasive product compared to previous state-of-the-art methods. This allows the use of abrasive particles significantly finer than P1000 grit while maintaining the dust removal properties of the mesh abrasive article, resulting in a smoother finish, finer scratches, and an overall improved quality of the abrasive product. Other possible grit sizes include P1200, P1500, P2000, or P2500 grits and smaller.

Claims

1. 1. A method for making a mesh abrasive article, comprising: providing a polishing sheet having a first surface and a second surface opposite the first surface, the polishing sheet including a base layer that is a continuous impermeable substrate; forming a pattern of slits in the abrasive sheet to form a slitted abrasive sheet having a plurality of slits, the plurality of slits extending through at least the first surface; stretching the slitted abrasive sheet to a flattening strain threshold such that the plurality of slits in the slitted abrasive sheet form a plurality of apertures having stressed open areas, thereby forming an apertured abrasive sheet; A method comprising:

2. 2. The method of claim 1, wherein an edge is formed adjacent to one of the plurality of slits, and the pattern is configured such that when stretched to a flattening strain threshold, less than 5% of the surface area of ​​the plurality of edges of the polishing sheet protrudes outside the plane of the polishing sheet.

3. The method of claim 1 , wherein the pattern is a single slit pattern, a multiple slit pattern, a composite pattern, or a combination thereof.

4. 2. The method of claim 1, wherein the single slit pattern includes skip slits with bridge regions between the skip slits along the slit direction, and multiple strands are formed between the bridge regions after tensioning.

5. The method of claim 4 , wherein the pattern is a wave pattern.

6. The method of claim 1 , further comprising laminating the base layer to an adhesive layer to form the mesh abrasive article.

7. 7. The method of claim 6, wherein the laminated apertured abrasive sheet has an average material height to thickness ratio in the range of 0.6 to 1.7 when subjected to the planarization strain threshold, as measured using a topographical profile method.

8. 7. The method of claim 6, wherein the tensioning causes at least one twist in the strands of the apertured abrasive sheet and the lamination does not cause the strands to fold over.

9. 7. The method of claim 6, wherein air is flowed through the adhesive layer at a flow rate of at least 1.0 L / s to remove dust from the abrasive surface through the mesh abrasive article during use.

10. 7. The method of claim 6, wherein the mesh abrasive article has an air permeability of greater than 377 cubic feet per minute per square foot as measured according to ASTM D737-18(2023).

11. 10. The method of claim 1, further comprising laminating the adhesive layer to the polishing sheet before skip-slitting the polishing sheet, wherein the pulling causes portions of the adhesive layer corresponding to the slits to break and form openings.

12. 10. The method of claim 1, further comprising clamping the apertured abrasive sheet, wherein the clamping results in a fixed aperture area of ​​at least 10% of the stressed aperture area of ​​one of the plurality of apertures, and wherein the clamping comprises applying heat or pressure to the apertured abrasive sheet.

13. 13. A first mesh abrasive article formed by the method of any one of claims 1 to 12, wherein the tensioning forms a first open area and the abrasive sheet has a grain size.

14. 13. A second mesh abrasive article formed by the method of any one of claims 1 to 12, wherein the tensioning is different from the tensioning of the first mesh abrasive article of claim 13 to form a second open area that is different from the first open area, and wherein the second mesh abrasive article has the same grit size, pattern, and slit dimensions as the first mesh abrasive article.

15. a planar coated abrasive sheet including a plurality of strands and a plurality of openings formed by straining a plurality of slits on the coated abrasive sheet, wherein a plurality of bridge regions are formed between ends of the plurality of openings along a first direction, the plurality of strands extending diagonally between the bridge regions, the plurality of strands being connected to one another at the bridge regions, at least some of the plurality of strands being separated from one another by the plurality of openings, and the planar coated abrasive sheet being strained so as not to overlap one another when laminated to the adhesive layer; an adhesive layer to which the coated abrasive sheet is laminated, thereby providing a mesh abrasive article that is breathable; and A mesh abrasive article comprising:

16. 16. The mesh abrasive article of claim 15, wherein the adhesive layer has an air permeability of greater than 377 cubic feet per minute per square foot as measured according to ASTM D737-18(2023).

17. 16. The mesh abrasive article of claim 15, wherein the coated abrasive sheet has an abrasive major surface and a non-abrasive back major surface, and no portion of the back major surface is exposed above the abrasive major surface.

18. The coated abrasive sheet is The base layer and a functional layer disposed on the base layer, the functional layer comprising abrasive particles having a size equal to or less than P1200 grit; 16. The mesh abrasive article of claim 15, comprising:

19. 16. The mesh abrasive article of claim 15, wherein the base layer comprises a resilient polymeric material having an elongation to break of at least 30%.

20. 16. The mesh abrasive article of claim 15, wherein the adhesive layer has an open area ratio of at least 20%.

21. 16. The mesh abrasive article of claim 15, wherein the plurality of slits form a sinusoidal pattern of skip slits.

22. 16. A first mesh abrasive article according to claim 15, having a grit size, a pattern, and a first open area; a second mesh abrasive article having the same grit size and pattern as the first mesh abrasive article and the same construction as the first mesh abrasive article, but having a second open area different from the first open area; Equipped with The kit, wherein the first mesh abrasive article and the second mesh abrasive article have different cutting rates or finishing characteristics.

Images