Mesh abrasive article with slit pattern and method of making same

Abstract

Aspects of the present disclosure relate to a method of making a mesh abrasive article involving providing an abrasive sheet having a continuous substrate-impermeable base layer, and cutting the sheet in a pattern to create a slotted abrasive sheet. The slotted abrasive sheet is then tensioned until it reaches a strain up to a variable flat strain threshold, opening the slit into a stressed region and forming a plurality of openings, thereby forming an opened abrasive sheet.

Description

Background Art

[0001] It is common for dry sanding operations to generate large amounts of airborne dust. To minimize this airborne dust, abrasive disc tools are typically used while a vacuum is drawn through the abrasive disc from the abrading side, through the back of the disc, and into a dust collection system. To this end, many abrasives have holes incorporated into them to facilitate this dust removal. As an alternative to incorporating dust removal holes into the abrasive disc, there are commercial products in which the abrasive is coated onto the fibers of a mesh knit backing into which loops are knitted into the back of the abrasive article. The loops serve as the loop portion of a hook and loop attachment system for attachment to the tool. Mesh products are known to provide excellent dust removal and / or anti-filling properties when used with substrates known to heavily fill with traditional abrasives.

[0002] Conventional reticulated abrasive products have a uniform distribution of abrasive particles on the surface of the reticulated sheet, but may have uneven flatness due to the raised portion-forming nature of the knitted fiber bundles. Summary of the Invention

[0003] One aspect of the present disclosure describes a method for producing a reticulated abrasive article. The method involves starting with an abrasive sheet having a base layer, which is a continuous, impermeable substrate. The sheet is then cut in a pattern to produce a slit abrasive sheet, wherein the slits penetrate a first surface of the abrasive sheet. The slit abrasive sheet is subjected to tension until it reaches a strain that reaches a flattening strain threshold, thereby opening the slits into stressed regions and forming a plurality of openings.

[0004] In one embodiment, this produces an open abrasive sheet having a specific height to average material thickness ratio in the range of 0.6 to 1.7 when tested using a topography profilometry method.

[0005] Additional aspects of the present disclosure relate to a web-like abrasive article made using the aforementioned method.

[0006] Additional aspects of the present disclosure describe a reticulated abrasive article comprising a planar coated abrasive sheet and an attachment layer. The coated abrasive sheet comprises a plurality of strands and a plurality of openings formed by tensioning a plurality of slits in the sheet. A plurality of bridging regions are formed between the ends of the openings in a first direction, and the strands extend diagonally between the plurality of bridging regions. In addition, the strands are attached to each other at the bridging regions, and some of them are separated from each other by the plurality of openings. The tensioning is performed in such a manner that no strands fold after lamination. The coated abrasive sheet is laminated to the attachment layer, which produces a breathable reticulated abrasive article. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] To easily identify the discussion of any particular element or act, the most significant digit(s) in a reference number refers to the figure numeral that first introduces that element.

[0008] Figure 1 An abrasive sheet of the subject matter according to one embodiment is shown.

[0009] Figure 2 A slotted abrasive sheet of the subject matter is shown according to one embodiment.

[0010] Figure 3 A slotted abrasive sheet according to one embodiment is shown.

[0011] Figure 4 An opened abrasive sheet according to one embodiment is shown.

[0012] Figure 5A A first surface of a web-shaped abrasive article according to one embodiment is shown.

[0013] Figure 5B A slotted abrasive sheet according to one embodiment is shown.

[0014] Figure 6 A flow chart illustrating a method of making a web-shaped abrasive article according to one embodiment is shown.

[0015] Figure 7 An apparatus for winding a slit abrasive sheet according to one embodiment is shown.

[0016] Figure 8A 、 Figure 8B 、 Figure 9A 、 Figure 9B Abrasive sheets having diamond slit patterns of varying degrees of size and extension are shown according to one embodiment.

[0017] Figure 10A A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0018] Figure 10B A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0019] Figure 11A A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0020] Figure 11BA networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0021] Figure 12A A networked abrasive article is shown having openings of three different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0022] Figure 12B A networked abrasive article is shown having openings of three different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0023] Figure 13A A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0024] Figure 13B A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0025] Figure 14A A networked abrasive article is shown having openings of three different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0026] Figure 14B A networked abrasive article is shown having openings of three different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0027] Figure 15A A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0028] Figure 15B A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0029] Figure 16A A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0030] Figure 16B A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0031] Figure 17A Aspects of the subject matter according to one embodiment are shown.

[0032] Figure 17B Aspects of the subject matter according to one embodiment are shown.

[0033] Figure 18A A networked abrasive article is shown having openings of three different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0034] Figure 18B A networked abrasive article is shown having openings of three different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0035] Figure 19A A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0036] Figure 19B A non-diamond slit pattern is shown that provides for expansion of the slit abrasive sheet in at least one direction.

[0037] Figure 20A A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0038] Figure 20B A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least one direction.

[0039] Figure 21A A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least two directions.

[0040] Figure 21B A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least two directions.

[0041] Figures 22A to 22C A networked abrasive article is shown having a plurality of populations of expandable regions that provide expansion of the networked abrasive article in at least two directions, such as radial expansion.

[0042] Figure 23A A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least two directions.

[0043] Figure 23B A networked abrasive article is shown having openings of two different sizes and / or shapes that provide expansion of the networked abrasive article in at least two directions.

[0044] FIG. 24A to FIG. 24B A networked abrasive article is shown having openings of three different sizes and / or shapes that converge to provide expansion of the networked abrasive article in at least three directions.

[0045] Figure 25 An exemplary web-shaped abrasive article according to one embodiment is shown. DETAILED DESCRIPTION

[0046] Aspects of the present disclosure may be directed to a web-like abrasive article formed using an expandable pattern of slits on a coated abrasive sheet. When the slit abrasive sheet is tensioned, the slits expand to open and form a plurality of strands on the resulting slit abrasive sheet.

[0047] The pattern can be a single slit pattern, a multi-slit pattern, a composite pattern, or a combination thereof. In some embodiments, the pattern can include skipped slits and the height variation of the abrasive surface (after lamination) relative to the average material thickness of the abrasive sheet when subjected to a strain up to a flattenable strain threshold is in the range of 0.6 to 1.7 using a topographic profile method.

[0048] Additionally, tensioning can induce at least one twist in the strands when subjected to strain up to a flattenable strain threshold, but no folding occurs when the slit abrasive sheet is laminated or flattened. In one embodiment, no folding occurs when the slit abrasive sheet is subjected to strain up to a flattenable strain threshold and flattened. In one embodiment, after tensioning, less than 5% of the surface area of ​​the plurality of edges of the abrasive sheet protrudes out of the plane of the abrasive sheet.

[0049] The method may also involve laminating the base layer to the attachment layer to form the webbed abrasive article.

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

[0051] The lamination process may involve applying an adhesive to the base layer or the attachment layer, or applying pressure or heat to the base layer or the attachment layer.The attachment layer may be a mesh support interwoven with knitted loops or a pressure sensitive adhesive attached directly (to a backing pad).

[0052] Other steps in the method may include wrapping the slit abrasive sheet around a core member multiple times for tensioning, slitting the webbed abrasive article in the transverse and / or longitudinal directions, and securing the opened abrasive sheet. A webbed abrasive article formed by the method is also disclosed.

[0053] In some embodiments of the method, the first surface of the abrasive sheet is a functional layer, such as a structured abrasive, and the second surface is a base layer. The base layer can be a polymeric material, such as a stretchable elastic polymeric material having an elongation at break of at least 100%, or it can be a coated paper.

[0054] In at least one embodiment, the tensioning process occurs by wrapping the slit abrasive sheet around a core member extending in the axial direction a plurality of times, and may occur in the longitudinal direction, such that tension on the slit abrasive sheet causes plastic deformation of the slit abrasive sheet. The tension may be at least 1 pound per square inch. The method may also involve securing the opened abrasive sheet using heat, pressure, or both. Securing results in a secured open area of ​​an opening in the plurality of openings being at least 10% of the stressed open area of ​​the opening.

[0055] Heat can be applied via an in-line oven to secure the plurality of openings, and the applied heat can be at least 120 degrees Celsius and applied via blown hot air. The pressure applied during the securement can be at least 5 kg / linear centimeter and applied using a roller gap. The method also includes a reticulated abrasive article formed by the process disclosed herein, and can include cutting the reticulated abrasive article in the transverse and / or longitudinal directions.

[0056] Each of the plurality of slits is a slit when the web-like abrasive article is in an unstressed state, but at least some of the slits become open when the web-like abrasive article is in a stressed state. In summary, the disclosed method of making a web-like abrasive article includes providing an abrasive sheet having a continuous, impervious substrate as a base layer.

[0057] The abrasive sheet has a first surface and a second surface opposite the first surface. The method further includes cutting the abrasive sheet in a pattern and tensioning the slit abrasive sheet to a strain up to a flattenable strain threshold to create a plurality of openings, thereby forming an opened abrasive sheet. The web-like abrasive article may also involve attaching the base layer of the abrasive sheet to the attachment layer using an adhesive, heat, pressure, or any combination thereof.

[0058] Additionally, aspects of the present disclosure may be directed to a method of making a web-shaped abrasive article. The method includes providing an abrasive sheet having a first major surface and a second major surface opposite the first major surface. The abrasive sheet includes a base layer comprising an elastic polymer material having an elongation at break of at least 100%.

[0059] The method further includes skip-cutting the abrasive sheet in a longitudinal or transverse direction to form a slitted abrasive sheet having a plurality of slits formed therein, the plurality of slits penetrating the first surface.

[0060] The method includes tensioning a slit abrasive sheet to form an open abrasive sheet. The tensioning causes a plurality of slits in the slit abrasive sheet to form a plurality of openings having stressed open areas.

[0061] In one embodiment, tensioning the slit abrasive sheet occurs by winding the slit abrasive sheet multiple times around a core member extending in an axial direction to form an open abrasive sheet. The winding occurs in the longitudinal direction so that the tension on the slit abrasive sheet causes plastic deformation of the slit abrasive sheet.

[0062] The method also includes fixing the opened abrasive sheet to form a reticulated abrasive article. In one embodiment, applying heat can at least partially fix the opened pores to provide a fixed open area. In one embodiment, pressure can also be applied to at least partially fix the opened pores. Aspects of the present disclosure also relate to a reticulated abrasive article prepared according to the methods described herein.

[0063] Aspects of the present disclosure relate to a reticulated abrasive article comprising a planar coated abrasive sheet and an attachment layer. The coated abrasive sheet comprises a plurality of strands and a plurality of openings formed by tensioning a plurality of slits through the coated abrasive sheet. Bridging regions are formed between the ends of the openings in either the transverse or longitudinal direction, and the plurality of strands extend diagonally between the bridging regions. At least some of the plurality of strands are separated from one another by the plurality of openings and tensioned such that no strands fold after lamination. The coated abrasive sheet is laminated to the attachment layer, thereby producing a breathable reticulated abrasive article.

[0064] In some embodiments, the webbed abrasive article has an air permeability greater than 377 cubic feet per minute per square foot as measured via ASTM D737-18 (2023).The coated abrasive sheet can have an abrasive major surface and a non-abrasive back major surface without any back major surface exposed on the abrasive major surface.

[0065] In summary, the disclosed web-like abrasive article comprises a planar coated abrasive sheet having a plurality of strands and openings formed by tensioning a plurality of slits. The coated abrasive sheet is laminated to an attachment layer to obtain an air-permeable web-like abrasive article having a specific air permeability and an abrasive major surface.

[0066] Aspects of the present disclosure provide a kit comprising a first webbed abrasive article having a particular grit size and a first open area, and a second webbed abrasive article having the same grit size but a different second open area. The first webbed abrasive article and the second webbed abrasive article have different cut rates or finish characteristics, thereby allowing a user to select an appropriate webbed abrasive article for their particular application.

[0067] Aspects of the present disclosure relate to a method for making a webbed abrasive article and apparatus therefor. The method may include: pattern-cutting a flexible abrasive sheet; tensioning the slitted abrasive sheet to open the slits; and securing the opened abrasive material such that the slits remain at least partially open, thereby forming a webbed abrasive article (which may be a coated abrasive article). In one embodiment, securing the opened abrasive sheet may include applying heat at a temperature of at least 120 degrees Celsius to the opened abrasive sheet.

[0068] While some references discuss the use of slits to form open pores, such pores are not practical in the context of a reticulated abrasive article. In at least one embodiment, it has been found that the use of a flexible base layer known in the context of flexible abrasive sheets is advantageously adapted to stretch and does not break when subjected to tension. Thus, the resulting reticulated abrasive article forms pores useful for dust removal while maintaining structural integrity useful for abrasive applications, rather than the sheet breaking when tension is applied.

[0069] The present disclosure can be beneficial in several ways when manufacturing. First, as opposed to cutting holes or coating a mesh with abrasive particles, the method of creating slits in an abrasive sheet eliminates the need to remove burrs or other debris when converting an abrasive article precursor into its slit counterpart. This can save time and resources in the manufacturing process.

[0070] Second, using a web abrasive article made from a slit abrasive sheet allows for a flatter abrasive surface, which results in a finer finish and more abrasive in contact with the work surface.

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

[0072] Finally, the slits can be adjusted based on the application, allowing the product to be more versatile. For example, for a given grit size, a slit abrasive sheet can be stretched or tightened beyond a certain point to allow for a larger open area and reduce the cut rate without having to change the abrasive grit. This design flexibility can make the product more adaptable to different uses.

[0073] Figure 1An abrasive article 101 is shown for illustrating the construction of an exemplary abrasive article. The abrasive article 101 can be a coated abrasive article having an attachment layer. Various examples of the abrasive article 101 are commercially available in the form of film discs under the trade name "Hookit" from 3M Company (Saint Paul, MN).

[0074] For example, the abrasive article 101 can include a functional layer 102, which can be a coated abrasive layer for abrading a material. The functional layer 102 can also include a supersize coating.

[0075] The functional layer 102 can be disposed on a base layer 104. The base layer 104 can be formed of a material configured to deform in response to tension while having a degree of toughness to provide integrity to the functional layer 102.

[0076] In some embodiments, base layer 104 includes an elastomeric film. The elastomeric film can be integral, or it can itself be a composite film with multiple layers produced by coextrusion, thermal lamination or adhesive bonding. Examples of materials that can be used for elastomeric films include polyolefins, polyesters (e.g., those available under the trade name "HYTREL" from E.I. du Pont de Nemours & Co., Wilmington, Delaware), polyamides, styrene / butadiene copolymers (e.g., those available under the trade name "KRATON" from Kraton Polymers, Houston, Texas), and polyurethane elastomers (e.g., those available 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, or EPDM rubber; and combinations thereof. Additional examples of useful elastomeric films include those described in U.S. Pat. Nos. 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 RE 33353 (Heinecke). Still other useful elastomeric films include pressure-sensitive adhesive-coated polyurethane elastomeric films commercially available from 3M Company, St. Paul, Minnesota, under the trade name "TEGADERM."

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

[0078] In an exemplary embodiment, the substrate layer 104 has an elongation at break of at least 100%, at least 200%, at least 300%, at least 400%, or at least 500%, as measured under ambient conditions. Optionally, the substrate layer 104 has an elongation at break of at most 1000%, at most 800%, at most 700%, at most 600%, or at most 500%, as measured under ambient conditions.

[0079] In this patent application, elongation at break is determined according to ASTM International Test Method D882-12, "Standard Test Method for Tensile Properties of Thin Plastic Sheeting," published in September 2012 by ASTM International, West Conshohocken, Pennsylvania, using an extension rate of 10% of the gauge length per minute.

[0080] Preferred materials for base layer 104 are non-sticky under ambient conditions. For the purposes of this disclosure, the term "non-sticky" refers to a material that meets the Dahlquist criterion for a non-sticky substance, meaning it has a viscosity of less than about 3×10 5 Storage modulus (G') in Pascals (measured at 10 radians per second at ambient temperature), as described in U.S. Pat. No. 6,884,504 (Liu et al.). Also cited: Dahlquist Criterion, "Handbook of Pressure Sensitive Adhesive Technology," 2nd ed. (1989), pp. 172-176. Materials having a storage modulus less than or equal to this threshold value will be considered to exhibit tack as defined by the Dahlquist Criterion.

[0081] Preferred materials for the base layer 104 may have an elastic modulus between 5 MPa and 20,000 MPa, or alternatively between 10 MPa and 10,000 MPa, or alternatively 20 MPa to 5,000 MPa, or alternatively 30 MPa to 1,000 MPa, or alternatively 30 MPa to 500 MPa. One way to measure the elastic modulus is to expose a cross section of the layer and perform an indentation test. The indentation test may follow the principles of ASTM E2546 Standard Practice for Instrumented Indentation Testing, except that the contact stiffness may be determined via a continuous stiffness method such as found on the Agilent G200, which has a higher accuracy in determining the contact stiffness than using the slope of the unloading curve, particularly for soft materials where creep causes distortion of the unloading curve.

[0082] In one embodiment, the upper glass transition temperature Tg of the base layer 104 is selected to be higher than the operating temperature of the functional layer 102 to reduce the possibility of relaxation due to the heat generated by sanding, which may cause the material to deform. In one embodiment, this can be achieved by blending various polymers with different glass transition temperatures.

[0083] A fused silica calibration standard (with a nominal E of 72 GPa) can be tested before and after sample testing to verify tip integrity. All tests can be performed on an Aglient G200 nanoindenter with a DCM head and a Berkovich diamond probe in 0.05 s. -1 The test is performed at a constant strain rate of 500 nm, assuming a Poisson's ratio of 0.3. Sample cross-sections can be exposed via microtomy, mounting in one-inch diameter epoxy disks, and subsequently polishing to a final finish with a 0.1 μm diamond-shaped lapping film. The following test parameters can be used: 1) surface approach distance 5000 nm; 2) surface approach speed 30 nm / s; 3) harmonic amplitude 1 nm; 4) harmonic oscillation 75 Hz; 5) depth setpoint 200 nm; 6) surface positioning contact stiffness 200 N / m. In some cases, testing may need to be continued beyond the 200 nm setpoint if steady-state has not yet been achieved.

[0084] Preferred materials for base layer 104 may have a hardness between 1 MPa and 2,000 MPa, or alternatively between 2 MPa and 1,000 MPa, or alternatively 4 MPa to 500 MPa, or alternatively 5 MPa to 100 MPa, or alternatively 5 MPa to 30 MPa. This test may be performed using the indentation method described above.

[0085] In at least one embodiment, the base layer 104 can be formed of a coated paper or a polymeric material that is a continuous, impermeable substrate. For example, the continuous, impermeable substrate should be unbroken (before cutting), and will typically exclude uncoated woven and nonwoven substrates.

[0086] The base layer 104 preferably has a substantially uniform thickness across its major surface. The average thickness of the base layer 104 can be at least 50 microns, at least 60 microns, at least 70 microns, at least 90 microns, at least 100 microns, or at least 120 microns. At the upper end, the average thickness can be at most 300 microns or at most 150 microns.

[0087] To enhance adhesion between the base layer 104 and its adjacent layers, the base layer 104 can be chemically primed or otherwise surface treated, such as by corona treatment, ultraviolet radiation treatment, electron beam treatment, flame treatment, or surface roughening. For example, aspects of the present disclosure relate to a base layer 104 having an elastomeric primer / make coat layer disposed thereon, which is further covered with a conventional coated abrasive formulation in the functional layer 102. One aspect of the present disclosure is that this continuous elastomeric primer layer can prevent the abrasive in the functional layer 102 from shelling during the tensioning process.

[0088] The base layer 104 may have an optional adhesive layer 106 for attaching the attachment layer 108 thereto. For example, the adhesive layer 106 may be any moisture-curable adhesive. In one embodiment, the adhesive layer 106 may be a spray-on adhesive to allow the fabric to cover the holes while maintaining sufficient porosity to allow dust ventilation from the front. It is suggested that a moisture-curable polyurethane adhesive applied by a starvation die or gravure coating would be a better way to achieve this lamination. The adhesive should become non-tacky during the cooling, drying, or curing process to prevent dust adhesion and subsequent sticking of the loop fabric.

[0089] The attachment layer 108 can be a layer used to attach the abrasive article 101 to a sanding tool. In at least one embodiment, the attachment layer 108 is a knitted loop structure corresponding to a hook-and-loop type system. In one embodiment, the attachment layer 108 can be an adhesive layer 106. For example, the attachment layer 108 can include a pressure-sensitive adhesive for attaching the abrasive article 101 to a separate back-up pad, such as the back-up pad commercially available under the trade name "Stikit" as an adhesive-based film abrasive.

[0090] In one embodiment, the attachment layer 108 can be an adhesive that attaches the abrasive article 101 to a substrate. In one embodiment, the substrate can include a foam (such as a sanding block) or another abrasive sheet 101 to form a dual abrasive.

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

[0092] In some embodiments, the functional layer 102 covers no more than about 40%, no more than about 50%, no more than about 60%, no more than about 70%, no more than about 80%, no more than about 90%, no more than 95%, or even no more than about 98% of the first major surface of the attachment layer 108. In some embodiments, the functional layer 102 covers from about 50% to about 98%, from about 50% to about 95%, from about 50% to about 90%, from about 50% to about 85%, from about 50% to about 80%, from about 60% to about 98%, from about 60% to about 95%, from about 60% to about 90%, from about 60% to about 85%, from about 60% to about 80%, from about 70% to about 98%, from about 70% to about 95%, from about 70% to about 90%, from about 70% to about 85%, or even from about 70% to about 80% of the first major surface of the attachment layer 108. In some cases, this means that although the edge of adhesive layer 106 substantially overlaps the edge of attachment layer 108, e.g. Figure 1 As shown, the area of ​​the void is such that the third major surface of the functional layer 102 covers no more than 98% of the first major surface of the attachment layer 108 .

[0093] exist Figure 2 , a slit abrasive sheet 200 is shown, illustrating an exemplary configuration in which the abrasive article 101 (including the attachment layer) is cut through the attachment layer 108. For example, the attachment layer 108 can have a plurality of slits formed therein (exemplary slits 202 and slits 204 are shown, but the plurality of slits can include either type of slit or a combination of both).

[0094] In at least one embodiment, a slit abrasive sheet can be produced without an attachment layer 108, wherein the abrasive sheet (without the attachment layer 108) is cut in a pattern and then laminated to the attachment layer 108. For example, a slit abrasive sheet can be produced without an attachment layer 108, wherein the abrasive sheet (without the attachment layer 108) is cut in a pattern and then laminated to the attachment layer 108 in a separate step.

[0095] like Figure 2As further shown, the slitted abrasive sheet 200 has slits 202 and slits 204 extending across the first surface 110. In one embodiment, the slits 202 extend completely through the functional layer 102, the base layer 104, the optional adhesive layer 106, and at least partially through the attachment layer 108. For example, the slits 202 may extend at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% through the attachment layer 108 without extending through the attachment layer 108.

[0096] In one embodiment, the slits 204 can also extend completely through the entire slotted abrasive sheet 200, including the attachment layer 108. For example, the slits 204 can penetrate all layers (functional layer 102, base layer 104, adhesive layer 106, and attachment layer 108) from the first surface 110 to the second surface 112. In one exemplary embodiment, the slotted abrasive sheet 200 has a plurality of slits that are evenly spaced apart from one another and extend across most, if not all, of the major first surface 110.

[0097] When the slit abrasive sheet 200 is in the relaxed configuration, the plurality of slits preferably have a maximum width that is substantially zero or near zero, but for illustrative purposes, Figure 2 Each slit has a pair of matching and substantially continuous slit surfaces. The slit surfaces may contact each other along the entire depth dimension of the slit (as is possible in slit 204), at various points along the depth dimension, or at the base (i.e., deepest point) of the slit (as is possible in slit 202).

[0098] Providing a plurality of slits in the slit abrasive sheet 200 is also advantageous from a manufacturing perspective, as opposed to cutting holes, because no burrs or other debris need to be removed when converting an abrasive article precursor, such as the abrasive sheet 101, into its slit counterpart. The slits 230 can be produced by mechanically cutting the abrasive sheet 101 at the first surface 110 and / or the second surface 112 of the abrasive sheet 101 using a blade or by converting using a laser.

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

[0100] Figure 3Another view of the slit 204 is shown. The slit 204 can have multiple slit dimensions, such as dimension 302 in a transverse direction 304. The slit 204 can have at least two edges 306, 308 formed therein on each side of the slit. The edges 306, 308 of the slit 204 can be in contact in the relaxed configuration. In one embodiment, multiple edges can be present on the slit abrasive sheet 200. In one embodiment, when the slit abrasive sheet 200 is in a stressed state, the edges 306, 308 can form strands of the open abrasive sheet.

[0101] exist Figure 4 In the embodiment, the open abrasive sheet 400 can be formed when tension is applied in at least one direction (eg, longitudinal direction 406 is shown), which tension causes the slits 204 (formed by the slits 204 in the embodiment) to open. Figure 3 302 ). The opening 402 may be formed by the edges 306, 308 of the slit 204. In one embodiment, the opening 402 may have a rhombus or oval shape with two pointed ends. For example, the opening 402 may have a major diagonal 404 and a minor diagonal 408, both of which are smaller than the dimension 302.

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

[0103] In one embodiment, the unstressed open area may be no greater than 40%, no greater than 30%, no greater than 20%, no greater than 15%, no greater than 10%, no greater than 5% of the stressed open area.

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

[0105] In one embodiment, the Fixed Open Area is at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 100% or at least 150% greater than the Unstressed Open Area.

[0106] In one embodiment, the Fixed Open Area is at least 2 times, at least 3 times, at least 4 times, at least 5 times, at least 6 times, at least 7 times, at least 8 times, at least 9 times, at least 10 times the Unstressed Open Area of ​​the (same) abrasive sheet.

[0107] In one embodiment, the opened abrasive sheet 400 is shown in a skipped slit or staggered pattern where the diagonal 408 of one opening 402 in a row 410 in the machine direction 406 is not aligned with the diagonal of another opening in an adjacent row 412 .

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

[0109] In one embodiment, the pattern of the plurality of slits can be arranged such that, when subjected to tension up to a flattenable strain threshold, no more than 15%, no more than 10%, or no more than 5% of the surface area of ​​the plurality of edges of the abrasive sheet protrudes out of the plane of the abrasive sheet. Thus, due to the tension, a twist may form that causes a portion of the edge to protrude out of plane and lift. However, the twist does not necessarily form a fold, as the lamination process or flattening can flatten the twist if the twist is not significantly prominent. Thus, in one embodiment, when subjected to strain up to the flattenable strain threshold, tensioning results in at least one twist in the strands of the unfolded abrasive sheet, and lamination does not result in any folding.

[0110] In one embodiment, the edges 306, 308 (which may also be strands) of the slits 204 do not protrude beyond the plane of the abrasive sheet when under tension or strain up to the flattenable strain threshold. Thus, in one embodiment, when the slit abrasive sheet or the opened abrasive sheet is subjected to strain up to the flattenable strain threshold, no torsion is formed and no folds are formed.

[0111] Figure 5A and Figure 5B A skipped slit pattern is shown with multiple slits. The slits shown extend in the transverse direction. However, it should be understood that the multiple slits can be arranged to extend in the longitudinal direction, thereby allowing tension in the transverse direction to stretch the abrasive sheet with slits. Figure 5A As shown, a plurality of openings 86 are formed in the abrasive sheet 84a (equivalent to the abrasive sheet 200 with slits) and penetrate the abrasive sheet 84a in the thickness direction. Figure 7 The apparatus shown winds up the abrasive sheet 84 and widens the slit 6 to form the opening 16. The opening 86 appears on the first surface 83c of the functional layer 83.

[0112] The opening 86 has a slit shape extending in the first direction D1. Specifically, the opening 86 has a shape such as an ellipse, an ellipse with pointed ends, or a roughly rectangular shape including a rhombus, because they are initially produced in the form of a slit, and the slit 6 is formed by widening them. The opening 86 has end portions 86a on both end sides in the first direction D1. The end portions 86a correspond to the two ends of the slit 6 in the first direction D1 before widening. The opening 86 is arranged at a prescribed interval in the first direction D1 and at a prescribed interval in the second direction D2 perpendicular to the first direction D1. In this embodiment, the first direction D1 corresponds to the axial direction in which the central axis CL extends in the transverse direction. In one embodiment, the opening formed can be a random configuration. For example, changes in tension in both the transverse and longitudinal directions can produce an opening 86 with a random shape and orientation.

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

[0114] The abrasive sheet 84 constituting the functional layer 83 may be divided into a plurality of regions 3 extending in the first direction D1 and arranged in the second direction. A boundary 4 extending in the first direction D1 is formed between a pair of regions 3. Figure 5B , virtual lines corresponding to some of the boundaries 4 are shown. When viewed laterally, the boundaries 4 form a straight line extending in the first direction D1. The boundaries 4 are defined as reference lines set for the openings 86 aligned at a predetermined interval in the first direction D1 among the plurality of openings 86. The reference lines of the boundaries 4 are defined as lines passing through the center of each of the openings 86 aligned in the first direction D1 and through the end 86a. However, due to manufacturing errors, the position of the end 86a may deviate, and the virtual line of the boundaries 4 does not necessarily completely overlap with the end 86a.

[0115] As described above, when a virtual line is set to pass substantially through the center positions of the plurality of openings 86 aligned in the first direction, the "boundary" corresponds to the virtual line. In addition, the "region" is a portion virtually defined by the boundary 4 and the boundary 4. When the abrasive sheet 84 is in an unwound state, the boundary 4 is defined by a virtual line passing through the linear slit 6, as shown in FIG. Figure 5B The region 3 is defined as a region where no slits 6 are formed in the extending direction of the abrasive sheet 84 .

[0116] As described above, the boundary 4 is defined based on the openings 86 arranged in the first direction D1. Thus, a plurality of openings 86 extending in the first direction are formed at the boundary 4. At the boundary 4, the plurality of openings 86 are arranged spaced apart from one another in the first direction D1. The locations where the openings 86 are spaced apart serve as connecting portions 7 that connect the regions 3 to one another. Thus, a pair of regions 3 adjacent to one another in the second direction D2 are connected to one another via the connecting portion 7 (or bridging region) formed between the openings 86.

[0117] Specifically, the "connecting portion" corresponds to a portion on the virtual line of the boundary 4 where the opening 86 is not formed. The term connecting portion may also be referred to herein as a bridging region. The connecting portion 7 is a portion attached so that when a force is applied to widen each region 3 in the second direction, its opening does not widen as much as the opening 86, and the adjacent regions 3 do not separate from each other.

[0118] In one embodiment, the spaces between the openings 86 in the diagonal direction can be referred to as strands. Thus, a strand 5 can extend from the midpoint of a connection 7 to the midpoint of a diagonal connection 7 on a different column or boundary 4. In one embodiment, a strand 5 can be formed from an edge adjacent to a slit between columns in the longitudinal direction, and a connection 7 can be formed from a portion between slits within the same column in the first direction D1.

[0119] Relative to the region 3, the opening 86 of the boundary 4 formed on one side in the second direction D2 and the opening 86 of the boundary 4 formed on the other side are arranged at different positions in the first direction D1. Specifically, for mutually adjacent boundaries 4, the opening 86 of one boundary has a staggered positional relationship with the opening 86 of the other boundary 4. Therefore, sometimes the structure in which multiple openings 86 (slits 6 before winding) are arranged in a staggered manner is called a "jump slit". In this embodiment, in the adjacent boundary 4 with one jump, the opening 86 and the boundary 4 are arranged at the same position. Specifically, a pair of boundaries 4 are set to form an opening 86 of a staggered pattern.

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

[0121] Figure 6 A flow chart of a method 600 of making a web-like abrasive article is shown. Figure 7 The device in.

[0122] In block 602, an abrasive sheet may be provided. As previously described, abrasive sheets including an attachment layer are commercially available from 3M Company. The abrasive sheet may be provided as a jumbo roll, and any of blocks 604, 606, or 614 may be performed.

[0123] In block 604, the abrasive sheet may have a plurality of slits formed therein that penetrate in the thickness direction. Figure 5B A slit abrasive sheet is shown in which the slits are arranged in a staggered manner (ie, skipped slits). In one embodiment, the slit abrasive sheet can be formed into a roll for further processing at a later time or continuously in a roll-to-roll manufacturing process.

[0124] As described above, the substrate layer contains a plurality of cuts or slits arranged in a pattern. In some embodiments, the pattern can be random, while in other embodiments, the pattern is arranged along at least one axis. The two-dimensional surface of the substrate layer can be considered to have two main orthogonal axes, commonly referred to as the x-axis and the y-axis. Due to the way the film is made, the x-axis is usually described as the "machine direction" or MD, and the orthogonal y-axis is described as the "cross direction" or CD. In one embodiment, the plurality of slits are arranged in a pattern along the machine direction. This means that the lengths of the plurality of cuts are aligned along the machine direction of the substrate layer. In one embodiment, the plurality of slits are aligned in the cross direction.

[0125] A plurality of slits arranged in a certain pattern are gaps, but when the substrate is in a stress-free state, these gaps are substantially invisible to the naked eye. When the abrasive article is in a stressed state, at least some of the gaps become visible to the naked eye. As used herein, the term "stress state" includes stretching, bending, or a combination thereof. Because the slits are very thin (i.e., substantially no width) in a stress-free state, they are typically described by their length and depth. Typically, the cut extends through the entire thickness of the substrate, so the depth is the same as the thickness of the substrate. A parameter that can describe the relationship between the length and width of the cut is the aspect ratio. The term "aspect ratio" is typically used to describe particles, but as used herein, the term is used to describe the pore size or void area in which no material exists. In some embodiments, the aspect ratio (ratio of length to width) of the cut is greater than 1000. When stress is applied, the aspect ratio of the slit decreases. An example of a suitable cut is a cut that is 1 cm long and 5 microns wide.

[0126] In some embodiments, the plurality of slits can include at least some continuous slits. By "continuous" is meant that the cuts extend from edge to edge of the surface. When stress is applied, these slits separate to form gaps in the backing that extend from edge to edge, and thus effectively divide the backing layer into two.

[0127] The slits can be more complex than the simple linear shapes described above. The slits can have various two-dimensional shapes, such as a cross, an asterisk, a wave, a mountain, letters, numbers, and the like.

[0128] In some embodiments, the slits are arranged in a pattern along the longitudinal direction of the substrate. Typically, the slits are formed by a process known as "jump cutting." In this process, a series of discontinuous slits are formed in the substrate in a linear manner. If you follow the slit line along the surface of the substrate, you will encounter a slit, the slit will end, and there will be an area that is not a slit. Then you will encounter a new slit, which will end, and you will encounter an area that is not a slit, and so on. This type of pattern is described in PCT Publication No. WO19 / 043621. In these patterns, the area between the end of one slit and the beginning of the next slit is called a bridging area. While a variety of patterns are suitable, in some embodiments, the pattern has a 50% offset. This means that when two linear arrays are present in the longitudinal direction, when viewed in the transverse direction, the bridging area of ​​the first array corresponds to the slits in the second array, and vice versa. Another example of a jump slit pattern is described in U.S. Patent Application No. 62 / 952,789.

[0129] A skipped slot abrasive sheet (i.e., an abrasive sheet having a plurality of slots ... Figures 5A to 5B In an abrasive sheet having a plurality of strands (a skipped slit pattern as shown), the abrasive sheet may include discontinuous slits interrupted by complete bridge regions. In an initial state, the plurality of strands and the discontinuous slits extend in a first direction to form a plane and are attached to each other at the complete bridge regions that are staggered in a second direction transverse to the first direction.

[0130] The thickness of the skipped slit sheet, and therefore the thickness of the plurality of strands, can be up to about 1 mm. In some embodiments, the thickness of the skipped slit sheet or strand can be up to about 400 microns, 250 microns, 150 microns, or 100 microns. In some embodiments, the thickness of the skipped slit sheet or strand can be in the range of 30 microns to about 225 microns, about 50 microns to about 200 microns, or about 100 microns to about 150 microns.

[0131] In a particular direction of the interrupted slits, the bridge region of the skipped slit sheet may have a length of at least 0.5 mm, 0.75 mm, or 1 mm.

[0132] Spreading can be performed to increase the width of the skip slit sheet in the CD (e.g., in the cross-web direction) to a sufficient degree that the minimum strands twist out of plane or onto themselves so that no folding occurs after lamination. Depending on the composition of the sheet base layer, the thickness of the sheet, the length of the slit portion of the intermittent slits, the length of the bridge area, and the distance between the slits, increasing the width of the skip slit sheet by at least 5% may be sufficient. In some embodiments, the width of the skip slit sheet may be increased by at least 10%, 15%, 20%, 25%, 30%, 40%, or 50%. Depending on various factors, the width of the skip slit sheet may be increased by as much as 100% or more.

[0133] In some embodiments, the plurality of slits are arranged in a pattern along more than one axis. This means that the lengths of at least some of the slits are not aligned with the machine direction of the substrate layer, but are deviated from alignment by an angle of up to 90°. Lengths that deviate from alignment by 90° with the MD of the substrate layer are considered to be aligned in the cross direction.

[0134] A plurality of slits can be made in a variety of different ways, as long as the method does not involve removing a large amount of material from the base layer, and the slits form gaps that are essentially invisible to the naked eye in an unstressed state, and when the abrasive article is in a stressed state, at least some of the gaps become visible to the naked eye. Among these methods, there is the following method: when the base layer is formed, for example, by extrusion, molding, machining, etc., the slits are introduced into the layer. Other methods are wherein after the base layer is formed, such as by cutting using a cutting tool (such as a knife, a linear blade, a rotary die blade, a water jet or a laser beam), or by punching the base layer using a stamping tool, the slits are introduced into the base layer. In some embodiments, the slits are made by feeding the base layer into a roller gap containing a rotary die blade and an anvil so that the die cuts through the base layer to form a cutting pattern.

[0135] Conceptually, a slit is a cut through a material with minimal thickness. In practice, the forming technique can involve the removal of material or the formation of a gap between the edges of the slit. Most cutting techniques produce a "groove" or a cut of some physical width. For example, a laser cutter can ablate some material to produce a slit, a router can cut away material to produce a slit, and even crush cutting can produce some deformation on the edge of the material forming the physical gap. Molding techniques require material between the opposing sides of the slit, thereby producing a gap or groove at the slit. In most cases, the gap or groove of the slit will be less than the thickness of the material. For example, a slit pattern cut into a 0.007 inch (178 micron) thick paper can have a gap of approximately 0.007 inch (178 micron) or less. However, it should be understood that the physical gap of the slit can be increased to many times the thickness of the substrate. As described above, the slit is formed in the backing layer in a manner that minimizes material removal. In this way, when the product is in a stress-free state, the slit is invisible and therefore no permanent opening is formed in the backing.

[0136] In one embodiment, the height difference to material thickness ratio may be within a certain range. For example, the value may be no greater than 0.6, 0.7, 0.8, 0.9, 1.10, 1.2, 1.3, 1.4, 1.5, 1.6, or 1.7, as determined by topography profiling. In one embodiment, the range may be 0.6 to 1.7.

[0137] In block 606, after the plurality of slits are formed during the cutting process, the slit abrasive sheet can be tensioned (i.e., the slit abrasive sheet is placed under stress, which can induce strain), which can form an open abrasive sheet. In at least one embodiment, tensioning can refer to stretching or straining the slit abrasive sheet, and the term "tensioning" can be used interchangeably with "tensioning."

[0138] In one embodiment, tensioning may be achieved using a variety of techniques, such as winding one end of the slotted abrasive sheet multiple times around a core member extending in an axial direction. In one embodiment, the winding may cause the strain applied to the slotted abrasive sheet to reach a flattenable strain threshold. In one embodiment, strain may also be applied in the transverse direction to tension the slotted abrasive sheet perpendicular to the longitudinal direction. In one embodiment, the winding may occur in the longitudinal direction such that the tension applied to the slotted abrasive sheet causes plastic and / or elastic deformation of the slotted abrasive sheet and further causes the multiple slits of the slotted abrasive sheet to form multiple openings, such as in Figure 4 and Figure 5A As described in.

[0139] In one embodiment, the flattenable strain threshold may depend on the material used and the pattern of the plurality of slits. As an example, as little as one pound per square inch (PSI) (6.8 kPa) may be used to open the plurality of slits in a skipped slit configuration. In one embodiment, 5 PSI (34.4 kPa) or 50 PSI (68 kPa) may be used to fully open the slits to a fully open opening with a stressed open area.

[0140] In one embodiment, the flattenable strain threshold can be reached at the point where the maximum open area percentage in the opened abrasive sheet is achieved without folding after lamination. For example, if the maximum open area percentage is 35%, but the web abrasive article has folds, the flattenable strain threshold is exceeded.

[0141] In one embodiment, tensioning can use a tentering process where a set of clamps are fastened to either side of a slit abrasive sheet and the clamps are moved away from each other in opposite directions, thereby forming a plurality of openings, each having a stressed open area.

[0142] In one embodiment, the tensioning in block 606 may utilize a web handling process in which the slit abrasive sheet is accelerated by controlling the relative speeds of adjacent nip rolls or pulling rolls, thereby creating tension between two points in the slit abrasive sheet. The web handling process may operate in tandem with the winding process described herein.

[0143] In one embodiment, block 606 can occur at an elevated stretching temperature. For example, tensioning can occur above ambient conditions to allow for a greater degree of opening of the plurality of slits when forming an opening having a stressed open area. In one embodiment, the elevated temperature can be above the highest glass transition temperature of the substrate layer. For example, the stretching temperature can be at least 60 degrees Celsius, at least 70 degrees Celsius, at least 80 degrees Celsius, at least 90 degrees Celsius, at least 100 degrees Celsius, at least 110 degrees Celsius, or at least 120 degrees Celsius.

[0144] As an example, Figure 7 As shown, the step of winding the abrasive sheet 84 around the core member 82 extending in the axial direction is performed multiple times. Figure 7 The winding device 50 shown performs dry winding. The winding device 50 includes a drum body 51 that holds an abrasive sheet 84 in which the slits 6 are formed. The winding device 50 feeds the abrasive sheet 84 from the drum body 51 and guides the abrasive sheet 84 to the winding section 52 via a plurality of rollers. The winding section 52 winds the abrasive sheet 84 around the core member 82 multiple times to form the drum body 54. It should be noted that at this time, the abrasive sheet 84 is applied with tension to form the slits 6 (see FIG. 1 ). Figure 5A) is wound in a widened state. It is also noted that the wound abrasive sheet 84 can be attached to remain on the roll body 54 by a prescribed method.

[0145] The tension can be set based on the tensioner 704 applied to the abrasive sheet 84. For example, the tensioner 704 (in conjunction with the winding of the core member 12) can establish tension on the abrasive sheet 84 by moving relative to one or more components (e.g., moving upward or downward relative to the mandrel 51). In one embodiment, the tension can be measured at any two points in the sheet within the region 706 (e.g., after unwinding from the mandrel 51 but before any securing or attachment of the attachment layer). Thus, forming a plurality of openings from the plurality of slits can form an open abrasive sheet in the region 706. The abrasive sheet 84 can be further stretched, causing the plurality of openings to become larger and forming a maximum open area from the boundaries of the plurality of slits.

[0146] In one embodiment, the open area of ​​one or more of the plurality of openings can be a stressed open area that occurs adjacent the web 51 (at area 710) when tension is applied to the slit abrasive sheet. If the tension is reduced or stopped (before any securing process), the stressed open area can shrink to an unstressed open area that occurs adjacent the web 51 (at securing area 710).

[0147] In block 608, the opened abrasive sheet formed in block 606 can be fixed using a fixing process for the plurality of openings. For example, the fixing in block 608 can be performed on the opened abrasive sheet so that at least some of the plurality of openings retain at least 10% of their stressed open areas while having unstressed open areas. After fixing in block 608, the opened abrasive sheet becomes a web-like abrasive article.

[0148] Securing may include various processes, such as in blocks 610, 612, and 614, which are not meant to be exhaustive. Block 608 may include any combination of blocks 610, 612, and 614. For example, securing may include applying both heat and pressure using one or more components of a manufacturing apparatus (e.g., winding apparatus 50).

[0149] Heat may be applied to the opened abrasive sheet to relieve any elastic deformation in the opened abrasive sheet in block 610. In one embodiment, heat may be applied in an in-line oven 708 that also at least partially holds / secures at least some of the plurality of openings as the stressed open regions of the openings return to secured open regions.

[0150] In one embodiment, heat may be applied by forced hot air. In one embodiment, the heat applied is at least 100 degrees Celsius, at least 110 degrees Celsius, and at least 120 degrees Celsius. The heating of the opened abrasive sheet in block 610 may be performed separately from the elevated stretching temperature in block 606 described herein.

[0151] In block 614 , the winding device 50 may apply pressure to the unwound abrasive sheet to form a webbed abrasive article.

[0152] In one embodiment, the applied pressure can be applied with at least one roller (e.g., using nip 702). Nip 702 can subject the opened abrasive sheet to heat and / or pressure (e.g., with a heated roller) and can secure the openings so that spring forces do not cause the openings to revert to slits.

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

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

[0155] although Figure 7 Only one set of roller nips 702 is shown, but any number of roller nips 702 are possible. Depending on the linear speed of the abrasive sheet 84, the abrasive sheet 84 may be exposed to the applied heat and / or applied pressure for no more than 10 seconds, no more than 30 seconds, no more than 45 seconds, or no more than 1 minute. In one embodiment, the opened abrasive sheet may be flattened to secure the opening.

[0156] Fixing can also include block 614, which includes applying a carrier pad to the non-functional side of the opened abrasive sheet. The carrier pad can provide an additional surface to fix the opened opening. The carrier pad can be commercially available from 3M Company (St. Paul, Minnesota) under the trade name 602197 PET film.

[0157] In one embodiment, one or more of blocks 610, 612, or 614 can be performed concurrently or simultaneously within the method 600. In one embodiment, heat can be applied simultaneously with pressure and / or the carrier pad. For example, the abrasive sheet 84 can be allowed to cool and collect on the roll body 54. In one embodiment, the pressed abrasive sheet can be quenched at a temperature below the glass transition temperature of the base layer to fix the stressed configuration.

[0158] In block 615, the abrasive sheet can be attached to the attachment layer. In one embodiment, the base layer of the uncut abrasive sheet can be attached to the attachment layer before cutting the abrasive sheet in block 604. In block 615, the attachment can be performed by laminating the opened abrasive sheet and the attachment layer (such as a hook and loop fastener). Lamination refers to the process of attaching two or more material layers (e.g., an opened abrasive sheet and an attachment layer) together by heat, pressure, or adhesive, which can be further described herein. In one embodiment, the base layer of the opened abrasive sheet can be laminated (directly) to the attachment layer (e.g., without using a release liner intermediate).

[0159] The lamination process of the functional layer onto the attachment layer typically begins with the preparation of the two layers. For example, the attachment layer can be a pressure sensitive adhesive, hook and loop material, or other mechanical fastening means. The two layers can be aligned and compressed together using a laminating device that can apply heat and pressure to the functional layer and the attachment layer similar to block 608. For example, the applied pressure can occur at a pressure of less than 1 MPa, such as at least 0.1 MPa. Figure 7 As shown, the lamination process is not shown, but a separate sheet of attached layers may be introduced just before the in-line oven 708.

[0160] The lamination process can be achieved using a variety of techniques, including hot melt, solvent-based, and water-based adhesives. Additionally, variations of the lamination process can include the use of a release liner to allow for easier handling and storage of the abrasive sheet prior to use.

[0161] The attachment layer can be breathable. For example, the resulting mesh abrasive article or attachment layer can have an air permeability greater than 100 cubic feet per minute per square foot, 200 cubic feet per minute per square foot, 300 cubic feet per minute per square foot, or greater than 377 cubic feet per minute per square foot, as measured by ASTM D737-18 (2023). The attachment layer can be a mesh or mesh backing. The mesh backing can be distinguished from other fabrics based on the size of the holes formed therein. In at least one embodiment, the holes in the mesh backing can be formed by yarn (if knitted or woven) or by polymer vertical and horizontal strands (if extruded). Due to the properties of knitted products, the holes can have different sizes. In at least one embodiment, the mesh backing 102 can have an average size of 0.5 square millimeters. In at least one embodiment, the mesh backing 102 can have an open area of ​​at least 20%, at least 30%, at least 40%, at least 45%, or at least 50%, or even at least 60%. In at least one embodiment, the mesh backing 102 can have an initial open area of ​​between 40% and 60%, inclusive.

[0162] In at least one embodiment, the web backing may further include an adhesive.

[0163] If the mesh backing is a fabric (woven, nonwoven, or knitted), the fabric may have the following properties. Various fabric mesh backings are commercially available from Sipip SpA (Cene, Italy) or Scott and Fyfe Ltd. (Tayport, UK).

[0164] In at least one embodiment, the backing can have a yarn thickness of at least 100 microns, at least 150 microns, at least 300 microns, at least 300 microns or at least 350 microns. In another measurement, the yarn can have a total denier of not more than 3000 deniers, not more than 1000 deniers, not more than 500 deniers. In at least one embodiment, the yarn can have a breaking toughness of at least 300mN / tex as measured by ASTM D2256. The backing can also have a fabric weight of not more than 300gsm (grams per square meter), not more than 220gsm or not more than 120gsm. The backing 102 can have a fabric weight of at least 40gsm.

[0165] In at least one embodiment, the mesh backing can be mostly planar, and the Kawabata evaluation system can be used to establish the surface friction and roughness of the plane of the mesh backing. Therefore, in one embodiment, the attachment layer is planar and flat. In the context of mesh fabrics such as knitted fabrics, "flat" or "planar" refers to the property of the fabric surface when the fabric surface is free of any visible lumps, bumps or ridges or is otherwise not configured to follow the contours of the body. In this context, flatness is caused by the yarns used to form the mesh fabric being evenly distributed without any waves or thick areas that could cause unevenness. This is a desired quality for many types of mesh fabrics because it can provide a smoother appearance and a more uniform texture.

[0166] In at least one embodiment, a plane can be established based on the majority of the surface area or cross-sectional area of ​​the yarn or other material in a single plane. For example, if a fabric has a solid surface area of ​​50% in a first plane, but a solid surface area of ​​30% in a second plane, the first plane can be the reference plane. Thus, the loops (if knitted) can be elevated relative to the reference plane. The reference plane can be approximately parallel to the flat surface on which the mesh backing rests. In at least one embodiment, the plane of a woven fabric can be established by the weft yarns.

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

[0168] In block 616, the winding device 50 may further cut / package the abrasive sheet 84. Additional processing in block 616 may include converting steps, such as cutting the roll 54 into smaller units. For example, the web abrasive article may be cut in the transverse and / or longitudinal directions to form different form factors.

[0169] Figures 8 to 24 show a range of slit patterns, with "A" panels showing the film in a cut and unstressed / non-networked state, and "B" panels showing the same film pattern in a stressed / networked state. References to figure numbers may include either Figure A or Figure B unless otherwise specified.

[0170] In Figures 8, 9, 10, 13, 15, 16, 17, and 19, a networked abrasive article 10 is shown having a longitudinal direction and a width direction, and comprising a plurality of strands 16 attached to each other at bridge or connecting regions 18 in the abrasive material and separable from each other between the bridge regions 18 to provide openings 22 in the abrasive material, wherein the openings 22 provide a variable stretchable region, and wherein each of the openings 22 has a longitudinal dimension 12, a width dimension 14, and each of the plurality of strands 16 has a thickness 15, and wherein the networked abrasive article 10 is stretchable in at least one direction. In some embodiments, the stretching direction is the longitudinal direction, such that stretching occurs along an axis parallel to the longitudinal dimension 12 of the networked abrasive article 10. In some embodiments, the stretching direction is the width direction, such that stretching occurs along an axis parallel to the width dimension 14 of the networked abrasive article 10.

[0171] In some embodiments, the openings 22 are larger in the longitudinal direction 12 than in the width dimension. For example, in some embodiments, such as those depicted in Figures 8, 9, and 17, the openings 22 have a diamond shape. In some embodiments, such as those depicted in Figures 10, 13, 15, 16, and 19, the openings have shapes other than diamond shapes. As shown in Figures 8, 9, 10, 13, 15, 16, and 17, a slit 11 or perforation of a specific size is present in the network-like abrasive article 10, which produces the openings 22 shown in Figures 8, 9, 10, 13, 15, 16, and 17.

[0172] In one embodiment, Figures 8-9 may be considered a "simple slit," which is defined herein as a slit having exactly two ends.

[0173] Now referring to Figures 11 to 14, 19, and 20, in some embodiments, the network-shaped abrasive article 10 disclosed herein provides two sets of openings to achieve more complex extensibility. For example, Figure 14AAs shown, there are two slits 11, 31 or perforations of specific sizes in the network-like abrasive product 10, which produce Figure 14B Openings 22, 16 are shown.

[0174] Referring now to Figures 12, 14 and 18, in some embodiments, the networked abrasive sheet 10 disclosed herein provides more than two sets of openings to achieve more complex extensibility. Figure 12A 、 Figure 14A 、 Figure 18A As shown, there are slits 11, 21, 31 or perforations of various sizes or shapes in the network-like abrasive sheet 10, which produce Figure 12B 、 Figure 14B 、 Figure 18B Openings 22, 23 are shown.

[0175] In some embodiments, the networked abrasive sheet 10 can be described by the relationship of one slit to another slit before the article is stretched and after the article is stretched and has at least partially returned to its pre-stretched state. If not specified, any degree of overlap or lack thereof refers to at least the degree of overlap measured before the networked abrasive sheet has been stretched (e.g., in a pre-stretched state). Specifically, the degree of overlap of slits that are offset relative to an axis perpendicular to the longitudinal dimension 12 (or offset relative to an axis perpendicular to the width dimension).

[0176] In at least one embodiment, the abrasive sheet 10 depicted in FIG12 can be a multi-slit pattern. As used herein, a "multi-slit pattern" is defined as a pattern that forms a first set of adjacent rows of individual slits across the transverse (i.e., cross) direction of the sheet, wherein the individual slits within the first set of adjacent rows are aligned in the transverse direction. In a multi-slit pattern, the first set of adjacent rows form a repeating pattern with at least a second row along the axial length (i.e., longitudinal direction) of the sheet, wherein the slits in the first set of adjacent identical rows are offset in the transverse direction relative to the slits in the second row. The term "multi-slit pattern" can include, for example, a double-slit pattern, a triple-slit pattern, and a quad-slit pattern.

[0177] Figure 16A A pattern characterized by a single slit pattern comprising sinusoidally skipped slits is shown. For example, each midpoint of a slit is approximately aligned with the space between two adjacent slits in different columns. Figure 16B When the slits are opened, the pattern advantageously produces a high degree of flatness when tensioned to the flattenable strain threshold of the slit abrasive sheet. As used herein, a wavy pattern can be a two-dimensional slit pattern having a series of alternating ridges and valleys, which can be regular or irregular. A sinusoidal pattern can be a smooth and periodic type of wavy pattern with valleys and peaks alternating above and below a baseline.

[0178] In an alternative embodiment, at least a portion of the slits can be "compound slits," which are slits with more than two ends. In Figure 23, a straight imaginary line extends between and connects these ends. In this embodiment, the straight imaginary line extending between and connecting the ends of a first slit is substantially collinear with the imaginary line extending between and connecting the ends of directly adjacent rows of slits. In this exemplary embodiment, all straight imaginary lines extending between and connecting the ends of the slits in a single row are roughly collinear. However, the area between the ends of each slit in the slit is not collinear with the imaginary line connecting the ends of the slits in each row.

[0179] Referring now to Figures 21-24, in some embodiments, the networked abrasive article 100 is stretchable in more than one direction.

[0180] In some embodiments, the networked abrasive article 100 has a longitudinal direction and a width direction, and has a plurality of abrasive material regions 116 that are separable from one another to provide openings 122 in the abrasive material, wherein each of the openings 122 has a longitudinal dimension 112 and a width dimension 114, and wherein the networked abrasive article 100 is stretchable in at least two directions.

[0181] In some embodiments, the disclosed article 100 further comprises a group 124 of a plurality of regions 116 extending radially from a common intersection 125. In some embodiments, the disclosed article 100 provides a first abrasive brightness when separated into a first width dimension between the plurality of regions 116 of abrasive material 20, and provides a second reflective brightness when separated into a second width dimension between the plurality of regions 116 of reflective material 20.

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

[0183] FIG21 and FIG23 illustrate an alternative slit configuration known as a biaxial multi-slit pattern. While the slits in the previously described multi-slit patterns (such as the dual-slit pattern of FIG12) are parallel to one another, some slits may have an orientation that is non-parallel to the orientation of the other slits in the pattern. In one embodiment, the abrasive sheet 100 has a slit pattern in which half of the slits 121 are oriented in the longitudinal direction and the remaining half of the slits 111 are oriented in the transverse direction or cross direction. Slits 121 and 111 otherwise collectively provide a multi-slit pattern as previously described.

[0184] Figure 21A The biaxial multi-slit pattern enables the abrasive sheet to be unfolded into Figure 21BThe three-dimensional stressed configuration shown. By tensioning along both the longitudinal and transverse orthogonal tension axes Figure 21A Abrasive sheet 100, obtained Figure 21B The stressed configuration.

[0185] Optionally, and as shown, the tension axis corresponds exactly to the longitudinal and transverse directions. Applying tension along the tension axis can occur simultaneously or sequentially. In some cases, tensioning along a single axis is sufficient to stretch the abrasive sheet, especially when that axis is angled with both slits 121 and 111 (e.g., at a 45-degree angle to both).

[0186] In some embodiments, a biaxial multi-slit pattern Figure 21A or Figure 23A The abrasive sheet is auxetic, that is, when stretched along one axis, it will stretch along the orthogonal axis. Expansion can also be achieved by applying tension along any axis that includes a combination of these two vectors, for example, tension applied along a 45-degree angle can be effective.

[0187] As shown in Figure 24, at least a portion of the slits can be "compound slits," which are slits with more than two ends. In the current example, a straight imaginary line extends between and connects these ends. In this embodiment, the straight imaginary line extending between and connecting the ends of a first slit is substantially collinear with the imaginary line extending between and connecting the ends of directly adjacent rows of slits. In this exemplary embodiment, all straight imaginary lines extending between and connecting the ends of the slits in a single row are roughly collinear. However, the area between the ends of each slit in the slit is not collinear with the imaginary line connecting the ends of the slits in each row.

[0188] Figure 24A An abrasive sheet 100 having a six-axis multi-slit pattern is depicted, wherein the slits 131, 121, and 111 are aligned along six different directions along the plane of the abrasive sheet 100, each direction forming a 60° angle relative to each of the other two directions. Each pattern of slits 111, 121, 131 is aligned along a given direction, and they may intersect with each other at their ends to form a repeating pattern of composite slits, each composite slit comprising a pair of slits oriented at a 60° angle relative to each other.

[0189] Figure 24B The abrasive sheet 100 is shown partially unrolled by applying tension, wherein components of the tension are aligned along the six tension axes shown.

[0190] definition

[0191] "Abrasive article" refers to an abrasive article that is stretched and configured to be laminated to or bonded to an attachment layer. In one embodiment, the abrasive article may refer to an intermediate and may exist on a roll (prior to conversion / cutting into finished products).

[0192] "Abrasive sheet" refers to an intermediate abrasive product that has not yet been cut, stretched, or attached to an attachment layer.

[0193] "Abrasive sheet plane" refers to the plane of the abrasive sheet (when not in a strained configuration) as determined by the maximum median height of the edge across the entire abrasive sheet.

[0194] "Breathable" refers to a material or structure that allows air or gas to pass through its surface or volume. The air permeability of a material can be quantified using various methods, including the Gurley method.

[0195] "Continuous impermeable substrate" refers to an unbroken layer of material that is impermeable to air (before cutting), which can include coated paper and polymer films, but generally excludes uncoated nonwovens and paper. The continuous impermeable substrate generally has less than 1% void space or has an air permeability rating of less than 2 cfm / sqft according to ASTM D737-18 (2023).

[0196] "Incision" refers to the surface area of ​​the sheet removed from the sheet when a slit intersects itself. However, it should be understood that many forming techniques result in the removal of some surface area of ​​the sheet which is not considered a "incision" for the purposes of this application.

[0197] “Different positions” means that the center positions of the connection portions in the second direction need to be different from each other, and as long as at least a part of the connection portions are different from each other, they may partially overlap.

[0198] "Elastomer" refers to any material that is capable of returning to its original shape when a deforming force is removed.

[0199] "Fixed open area" refers to the open area of ​​the opening after the fixing process has been performed and the webbed abrasive sheet is neither under strain nor subjected to tension.

[0200] "Fixing" refers to a process in which an article is transformed into a more dimensionally stable article or form. For example, fixing may refer to heating and / or applying pressure to a stressed slit abrasive sheet so that the openings do not return to their shape without fixing and applying stress. In some embodiments, fixing may refer to a process distinct from laminating.

[0201] "Flat" refers to the property of having a smooth and uniform surface without any protrusions, waves, wrinkles or other irregularities that may affect the accuracy or performance of the sheet. In one embodiment, flatness is established by the planar surface of the functional layer having a uniform thickness without the abrasive particles themselves. In one embodiment, flatness can be based on a height difference / average thickness ratio of less than 2, or less than 1.5, or less than 1.1 as determined by topographic profiling methods.

[0202] "Flat pressing" refers to compression in a direction normal to the plane of the sheet such that when the slit abrasive sheet is opened under tension, no portion of the strands overlaps any other abrasive portion of the sheet as such compression occurs.

[0203] "Flattenable strain threshold" refers to the maximum applied strain along the primary tension axis under certain conditions. In one embodiment, the conditions may be such that a slit abrasive sheet can be flattened onto a substrate orthogonal to the initial, untensioned plane of the sheet while maintaining the overall nominal strain of the sheet. In one embodiment, the conditions are such that when subjected to the maximum applied strain, the strain does not cause folding in the laminated web abrasive article, even if there is torsion in the strands of the unfolded abrasive sheet.

[0204] "Fold" refers to areas of the abrasive backing that are unintentionally folded during the tensioning process and secured after laminating the abrasive sheet to the attachment layer. Folds expose the non-abrasive backing surface on top of the functional abrasive surface. For example, folds can be caused by twisting that does not flatten after lamination or heat / pressure processes.

[0205] "Web abrasive article" refers to a continuous sheet of coated abrasive having holes formed therein to allow extracted dust to pass through and capable of being attached to the planar surface of a motorized sanding tool.

[0206] "Opening" refers to the open area created by subjecting a slit to tension. The opening can have a stressed open area, an unstressed open area, and / or a fixed open area, depending on whether the opened abrasive sheet is unstressed or stressed.

[0207] "Network-like" refers to a network-like formation of strands or areas joined at certain points.

[0208] In some embodiments, the present disclosure provides a networked abrasive article having a longitudinal direction and a width direction, and comprising a plurality of abrasive material strands attached to each other at bridge regions in the abrasive material and separable from each other between the bridge regions to provide openings in the abrasive material, wherein the openings provide a variably stretchable region, and wherein the abrasive material comprises a functional major surface and a less functional major surface, and wherein each of the openings has a longitudinal dimension, a width dimension, and each of the plurality of strands has a thickness, and wherein the networked abrasive article is stretchable in at least one direction.

[0209] In the present disclosure, stretching of a networked abrasive article is considered to be a change in the open area in the networked abrasive article. The networked abrasive articles disclosed herein can provide different amounts of open area when stretched in one or more directions.

[0210] As the networked abrasive article is stretched, the amount of open area increases, resulting in lower brightness and increased permeability. In some embodiments, stretching can be performed before the networked abrasive article is mounted on a substrate. In some embodiments, stretching occurs due to the user's movement, such as, for example, when the networked abrasive article is mounted on the elbow or knee area of ​​an active garment.

[0211] A "single slit pattern" refers to slits forming separate rows, each row extending transversely across the sheet, wherein the rows form a repeating pattern of separate rows along the axial length of the sheet, and wherein the pattern of slits in each row differs from the pattern of slits in an immediately adjacent row. For example, the slits in one row may be axially offset or out of phase with the slits in an immediately adjacent row. In some embodiments, each slit in the plurality of slits may include a plurality of peaks and valleys within the plane of the sheet.

[0212] "Jumping slits" refers to a pattern of multiple slits in which the midpoint of any slit in a slit column is not aligned with the midpoint of any slit in an adjacent slit column (along the vertical axis of the slit column).

[0213] "Slit" refers to a long, narrow slit or opening. As used herein, a "slit" is defined as a narrow slit that passes through an article to form at least one line, which can be straight or curved and has at least two ends. In one embodiment, perforation is a specific type of slit produced by making a series of small, regularly spaced slits along a line. These slits are designed to weaken the material along the perforated line, allowing it to be easily torn or separated along the line. Slits are generally not incisions. Specifically, many cutting techniques produce "grooves" or slits with a certain physical width. For example, a laser cutter will ablate some surface area of ​​a sheet to produce a slit, a router will remove some surface area of ​​the material to produce a slit, and even extrusion cutting will produce some deformation on the edge of the material, which deformation forms a physical gap on the surface area of ​​the material. In addition, molding techniques require material between the opposing sides of the slit, thereby producing a gap or groove at the slit. In various embodiments, the gap or groove of the slit will be less than or equal to the thickness of the material. For example, a slit pattern cut into a 0.18 mm thick metal foil may have slits with a gap of approximately 0.18 mm or less. However, it should be understood that the width of the slits can be increased to many times the thickness of the material and be consistent with the technology disclosed herein.

[0214] "Strain" refers to the deformation of a solid due to stress and can be measured as the change in length divided by the initial length of the material.

[0215] "Stressed open area" refers to the open area of ​​the opening when the opened abrasive sheet is under strain or subjected to tension.

[0216] "Stressed state" refers to the property of an abrasive sheet when it is subjected to tension along at least one axis up to a flattenable strain threshold.

[0217] The “topography profile method” refers to a method of comparing a flat surface of a base material with a raised portion of the base material, and is similar to the method described in WO2023037272.

[0218] "Twisted" refers to strands of an opened abrasive sheet that are twisted or bent out of the plane of the opened abrasive sheet, thereby forming a curved or convex shape or a partial helical shape.

[0219] "Unstressed open area" refers to the open area of ​​the opening of the open abrasive sheet that is unsecured and / or unstrained.

[0220] "Unstressed state" refers to the state of the abrasive sheet when no tension is acting upon it.

[0221] Example

[0222] Test Method

[0223] Topological Contour Method

[0224] The topological profile was determined using a Keyence VKX1100 confocal 3D measurement confocal microscope (Keyence Corporation, Osaka, Japan). A 4-inch × 4-inch combined strip was placed on a sample tray and evaluated at 2.5x magnification using annular and axial illumination. Four images of a 2" × 2" square were taken at 2.5x magnification and stitched together to form a single image for analysis. The resulting images were analyzed using VK Series Analyzer software (Keyence Corporation, Osaka, Japan). The associated height difference was determined by taking the difference between the height of the raised portion and the height of the adjacent portion and dividing the difference by the average thickness of the sample.

[0225] Abrasion test method

[0226] A 3" diameter disc was cut from each heat laminated flexible abrasive sample. The 3" disc was attached to a Festool LEX 377 / 2,5 sander connected to a Festool CT 36E dust extraction system. Compressed air was supplied to the sander such that the dynamic air pressure was 50 psi when the sander was operated with the throttle valve fully open. Each abrasive disc was tested on an unsanded portion of an 18" high by 24" wide motorized test panel (purchased from ACT Test Laboratories, LLC., Hillsdale, Mich.) by manually moving the operating sander in a linear motion in a single 18" high channel on the test panel using approximately 4 kg of down force for 30 seconds. The weight of the test panel was taken before and after the test and the difference was recorded as the cut value.

[0227] Surface finish measurement

[0228] After sanding, the finish (Ra, Rz, Rz max) of each sanding pass was measured at 5 locations using an S100 series profilometer equipped with a PK-03 diamond stylus available from Taylor-Hobson, Leicester, UK. The average of 5 measurements was recorded for each sample.

[0229] The samples were further visually evaluated under light to determine the finish, scratch density, and q-ing.

[0230] Air permeability measurement

[0231] The air permeability of abrasive articles is measured using a Gurley 4301 air permeability tester according to ASTM D737-18 (2023). The results of the air permeability test are expressed in cubic feet per minute per square foot (cfm / ft 2 ) is reported in units of . When

[0232] Fold determination method

[0233] Folding occurs when the laser-cut sample is stretched beyond the point where it can be heat laminated in a flat state. Folding can occur primarily along the strands, but can also occur in the bridge areas. In this case, the twist of the stretched laser-cut sample folds during lamination, exposing the non-abrasive backside of the abrasive backing on top of the abrasive surface. The number of folds on each sample was counted by viewing each 3" disc sample through a 2.75x magnification lens and manually counting the folds on each sample.

[0234] Abrasive area percentage

[0235] The % Abrasive Area of ​​the cut / tensile samples was determined gravimetrically using the following formula:

[0236] % Abrasive Area = (B / A) * 100%, where:

[0237] A = Mass of the parent unstretched 3" abrasive disc

[0238] B = Mass of the cut / stretched 3" abrasive disc

[0239] % Open Area = 100% - % Abrasive Area = (1-(B / A))*100%

[0240] "Stretch" refers to the value of strain + 100%.

[0241] Strain percentage determination

[0242] The percent strain is determined by taking a rectangular sample 78 mm long by 152 mm wide, stretching the rectangular sample in the longitudinal direction of the pattern, and measuring the final length with a ruler. The percent strain is the difference between the final length and the initial length of 78 mm divided by the initial length of 78 mm.

[0243] Sample preparation

[0244] The objects and advantages of the present disclosure are further illustrated by the following non-limiting examples. However, the specific materials and amounts thereof, as well as other conditions and details, recited in these examples should not be construed as unduly limiting the present disclosure. The following abbreviations are used to describe the examples:

[0245] ℃: degrees Celsius

[0246] cm: centimeters

[0247] g / eq.: grams / equivalent

[0248] g / m 2 : g / m²

[0249] g / mol: grams / mole

[0250] kg: kilogram

[0251] mil: 10 -3 inch

[0252] mm: millimeters

[0253] μm: micrometer

[0254] UV: Ultraviolet

[0255] W / in: Watts / inch

[0256] W / cm: Watt / cm

[0257] Unless otherwise noted, all reagents were obtained or purchased from chemical suppliers such as Sigma-Aldrich Company, St. Louis, Mo., or can be synthesized by known methods. Unless otherwise reported, all ratios are by weight.

[0258] The abbreviations of materials and reagents used in the examples are as follows:

[0259] ACR: trimethylolpropane triacrylate.

[0260] AMOX: di-tert-amyl oxalate.

[0261] BKG1: Backing 1; 120g / m 2 Heavy mesh netting was purchased from Sitip Technical Textiles of Cene, Italy.

[0262] CHDM: 1,4-cyclohexanedimethanol.

[0263] EP1: a bisphenol-A epichlorohydrin-based epoxy resin having an epoxy equivalent weight of 525-550 g / eq and an average epoxy functionality of 2, available as "EPON 1001F" from Momentive Specialty Chemicals, Inc., Columbus, Ohio.

[0264] EP2: a bisphenol-A epoxy resin having an epoxy equivalent weight of 185-192 g / eq and an average epoxy functionality of 2, available as "EPON 828" from Momentive Specialty Chemicals, Columbus, Ohio.

[0265] EP3: (3',4'-epoxycyclohexylmethyl) 3',4'-epoxycyclohexanecarboxylate.

[0266] ESTANE: a thermoplastic polyether-based polyurethane resin available under the trade designation "ESTANE 58887NAT 021" from Lubrizol Advanced Materials, Cleveland, Ohio.

[0267] FLL: an inorganic micronized functional filler obtained under the trade designation "MINEX 3" from Unimin Corp, New Canaan, Conn.

[0268] P600: P600 grade aluminum oxide abrasive mineral, available from Treibacher Industrie AG under the trade designation "ALODUR BFRPL."

[0269] PC1: A mixture of 4-phenylthiophenyldiphenylsulfonium hexafluoroantimonate and bis(hexafluoroantimonate)bis[4-(diphenylsulfonium)phenyl]sulfide in propylene carbonate, obtained from Aceto Corporation, Port Washington, NY, under the trade designation CPI 6976.

[0270] PC2: 2,2-dimethoxy-2-phenylacetophenone, obtained under the trade designation "IRGACURE 651" from BASF, Wyandotte, Mich.

[0271] PC3: η 6 -[Xylene (mixed isomers)]η 5 -cyclopentadienyl iron (1+) hexafluoroantimonate (1-).

[0272] PC4: ethyl (2,4,6-trimethylbenzoyl)phenylphosphinate, obtained from BASF Corporation, Wyandotte, Michigan, under the trade designation IRGACURE TPO-L.

[0273] PEP: a high molecular weight hydroxyl terminated saturated linear semicrystalline copolyester having a weight average molecular weight of 35,000 g / mol, purchased as "DYNAPOL 5 1227" from Evonik Industries, Parsippany, NJ.

[0274] PET: 1.97 mil (50 μm) thick polyester terephthalate film available from 3M Company under the trade designation 602197 PET FILM.

[0275] PI: 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0276] Prop Carb: Propylene glycol carbonate, available under the trade designation JEFFSOL PC from Huntsman Corp, Woodlands, Tex.

[0277] "ZNST": a 39 to 41 wt% aqueous zinc stearate soap dispersion available from eChem LTD, Leeds, UK. under the trade designation EC994C.

[0278] Preparation of primer resin

[0279] A series of primer resins were prepared as follows, based on the compositions listed in Table 1. AMOX, EP1, EP2, CHDM, and PEP were metered directly into a twin-screw extruder operating at 300 rpm at temperature zones of 30°C, 105°C, 110°C, 100°C, 65°C, and 60°C. This mixed resin was then fed into a spike mixer operating at 1750 rpm, and ACR, PC2, PC3, PC4, and PropCarb were metered directly into the spike mixer. The output of the spike mixer was fed into a heated coating die where the spike mixer flow rate was controlled to achieve the primer resin target on the abrasive backing.

[0280] Table 1

[0281]

[0282] Preparation of resin

[0283] Table 2 below lists the components and amounts used to formulate Size Resins 1 and 2. Each size resin was prepared by combining EP2, EP3, and ACR, and optionally FLL, in a container and mixing. Prior to abrasive fabrication, PC1 and PI were added to the premixed resin batch and stirred at room temperature for 30 minutes until homogeneous.

[0284] Table 2

[0285]

[0286] Method for making abrasive sheet

[0287] ESTANE resin was extrusion cast as the first thermoplastic polyurethane film onto 1.97 mil (50.04 μm) PET using a single screw extruder at an average thickness of 5 mils (127 μm). The primer resin was applied to the ESTANE film at a nominal coat weight of 16.5 g / m2, and the film assembly was passed under a Fusion UV Systems with one set of D-shaped bulbs and one set of V-shaped bulbs, both operating at 600 W / in (236 W / cm2). Abrasive ore P600 was then applied to the primer resin at a nominal coat weight of 28 g / m2, and the web was then heated under an infrared heater at a nominal web temperature setting of 100°C for approximately 7 seconds. The size resin was then roll-coated onto the make coat and abrasive grain at a nominal dry coat weight of 13 g / m² and passed under a fusion UV system with one set of H-shaped bulbs and two sets of D-shaped bulbs, all operating at 600 W / in (236 W / cm²). It was then processed through an infrared oven with a target exit web temperature of 125°C. ZNST was then applied to the size coat at a nominal coat weight of 9 g / m² and passed through a drying oven with a target exit web temperature of 135°C.

[0288] The abrasive web is then bent by wrapping it around a first 1 / 4 inch (6.35mm) diameter round metal rod, with the adhesive backing of the abrasive in contact with the rod. The rod is oriented at a 45° angle relative to the web direction. The web is wrapped around a 1 / 4 inch (6.35mm) diameter rod so that approximately half of the rod is in contact with the adhesive backing of the web. This produces a configuration in which the web movement before the rod is opposite to the direction of web movement after the rod. Once the web moves past the first rod, the abrasive web is wrapped around a second 1 / 4 inch (6.35mm) diameter round metal rod, with the back side of the abrasive in contact with the rod. The second rod is also oriented at a 45° angle relative to the web direction and is oriented at 90° to the first rod. The winding angles for the first and second rods are the same, and in both cases, the adhesive backing of the abrasive is in contact with the rod.

[0289] The resulting coated abrasive web was then kept at room temperature (ie, 20°C to 24°C) until used in subsequent examples.

[0290] Method of lamination to mesh web

[0291] The PET liner was removed from the abrasive and heat laminated to BKG1 using a SteamFast Model SF-680 iron purchased from Vornado Air LLC, Andover, Kansas. The iron was set to the "linen" setting and allowed to heat to a steady state. A 12" x 12" square of BKG1 was cut and placed onto a rigid cardboard substrate with the loop side in contact with the cardboard. A 7" x 7" square of abrasive was placed on top of BKG1 with the abrasive facing up, and the abrasive and BKG1 were secured to the rigid cardboard substrate. A cardboard / BKG1 / abrasive multilayer sample was placed on the bottom surface of the SteamFast iron with the cardboard side down. A sheet of paper release liner was placed on top of the abrasive with the release side down in contact with the abrasive. The iron was closed onto the multilayer sample and held in that position for 1 minute and 30 seconds. Thereafter, the multilayer sample was removed from the iron and allowed to cool to room temperature for 1 minute. Once cooled, the BKG1 and abrasive layer are now laminated together and removed from the rigid paperboard substrate.

[0292] Comparative Example C1 was prepared by cutting 3" diameter discs from each heat-laminated flexible abrasive sample before any cutting occurred as described below.

[0293] Making abrasive sheets with slits

[0294] The PET backing laminate was removed from the abrasive and laser cut according to a pattern using an Epilogue Fusion Laser Model 13000 operating at 75 watts, 100% speed, 70% power, and 50% frequency. A 12" x 12" square of BKG1 was cut and placed onto a rigid cardboard substrate with the loop side in contact with the cardboard. A 6" x 6" square of slit abrasive sheet was cut, manually stretched, and secured to BKG1 on a rigid cardboard substrate in the stretched position with the abrasive facing away from BKG1. The resulting multi-layer sample was placed in an iron and heat laminated to a mesh web as described above.

[0295] Flattenable strain threshold determination

[0296] Examples EX1, EX2, and Comparative Examples C2 and C3 were prepared by cutting 3-inch diameter discs from each heat-laminated flexible, slotted abrasive sample. Figure 16A Each of Examples EX1, EX2 and Comparative Examples C2 and C3 was laser cut and the pattern shown was applied to each sample. Figure 16BEach was prepared at different levels of strain similar to those shown. Comparative Example C3 was unstrained (thus, under zero tension). Each of the strained samples was pressed flat against a flat substrate while maintaining the overall nominal strain, and any portion of the sheet was evaluated for folding. Comparative Example C2 represents the amount of strain at which initial folding was observed.

[0297] The folds were counted, the % abrasive area calculated, and the Densometer measurements were performed according to the test method above. Table 3 summarizes the samples produced, percent strain, percent abrasive area, height difference / thickness via topography profilometry, open area, and number of folds.

[0298] For the 3 inch diameter sample, Comparative Example C2 was stretched beyond one fold, indicating that the flattenable strain threshold was reached.

[0299] Table 3 - Dimensions for different tension levels

[0300]

[0301] Surface finish of the sample

[0302] The samples were subjected to wear testing and surface finish measurements and the results are summarized in Table 4. Comparative Example C4 is commercially available from Mirka Ltd. (Finlan) as Abranet Ace P600.

[0303] Table 4 - Wear testing and surface finish measurements

[0304]

[0305] *A small amount of air leaks through the space between the loop fabric and the clamp, resulting in a non-zero measurement.

[0306] Thus, EX1 and EX2 have an air permeability of the web abrasive article greater than 377 cubic feet per minute-square feet (when measured according to the Air Permeability Measurement Method described herein), as well as an acceptable visual finish and a low overall cut volume.

[0307] P1200 Grit Example

[0308] A disc of commercially available 3M Purple Dressing Film P1200 (Part No. 30668) was hand laminated at room temperature to a 12 inch x 12 inch square of 3M Adhesive Transfer Tape 9453LE adhesive with the abrasive side of the disc facing away from the adhesive and a paper release liner on the opposite side of the adhesive. An Epilogue Fusion Laser Model 13000 was operated at 75 watts, 50% speed, 100% power, 50% frequency, according to Figure 16AThe abrasive / adhesive / paper backing is laser cut in the pattern shown.

[0309] Cut a 12 inch x 12 inch square of BKG1 and place it onto a rigid cardboard substrate with the loop side in contact with the cardboard. Remove the paper backing from the abrasive / adhesive / paper backing sample and secure one end to BKG1 on the rigid cardboard substrate with the other side as shown. Figure 16B The abrasive layer is shown stretched to 34% strain and secured to BKG1 on a rigid cardboard substrate in a stretched position with the abrasive facing away from BKG1. The BKG1 and abrasive layer are now laminated together and removed from the rigid cardboard substrate and cut into 3 inch discs. An example of P1200 abrasive grain is shown in Figure 25 000 abrasive grains. The final product uses P1200 abrasive grains, which are significantly finer than the currently commercially available P1000 abrasive grain products. Using the methods described herein, a finer abrasive surface can be obtained in the coated abrasive product compared to the current state-of-the-art methods. This allows the use of abrasive grains having a significantly finer particle size than P1000 abrasive grains while maintaining the dust removal properties of the mesh abrasive product, thereby providing a smoother finish with finer scraping, which improves the overall quality of the abrasive product. Other potential abrasive particle sizes used may be those less than or equal to P1200, P1500, P2000 or P2500 abrasive grain sizes.

Claims

1. A method for making a reticulated abrasive product, the method comprising: providing an abrasive sheet having a first surface and a second surface opposite the first surface, wherein the abrasive sheet includes a base layer, the base layer being a continuous, impermeable substrate; cutting the abrasive sheet in a pattern to form a slitted abrasive sheet having a plurality of slits formed therein, the plurality of slits penetrating at least the first surface; The slitted abrasive sheet is tensioned to a flattenable strain threshold, which causes the plurality of slits of the slitted abrasive sheet to form a plurality of openings having stressed open areas, thereby forming an opened abrasive sheet.

2. The method of claim 1 , wherein edges are formed adjacent to slits in the plurality of slits, wherein the pattern is arranged in such a manner that less than 5% of the surface area of ​​the plurality of edges of the abrasive sheet protrudes out of the plane of the abrasive sheet when under tension up to the flattenable strain threshold. 3 . The method of claim 1 , wherein the pattern is a single slit pattern, a multi-slit pattern, a composite pattern, or a combination thereof.

4. The method of claim 1, wherein the single slit pattern comprises skip slits having bridge regions between the skip slits in a cutting direction and having a plurality of strands formed therein between the bridge regions after tensioning. The method of claim 4 , wherein the pattern is a wavy pattern.

6. The method according to claim 1, further comprising: The base layer is laminated to the attachment layer to form the webbed abrasive article.

7. The method of claim 6, wherein the opened abrasive sheet has a height to average material thickness ratio in the range of 0.6 to 1.7 after lamination using a topography profiling method when subjected to the flattenable strain threshold.

8. The method of claim 6, wherein the tensioning causes at least one twisting in the strands of the unfolded abrasive sheet when subjected to strain up to the flattenable strain threshold, and the laminating does not cause any folding.

9. The method of claim 6, wherein air flows through the attachment layer at a rate of at least 1.0 L / s so that, in use, dust can be removed from the abrading surface by the web-like abrasive article.

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

11. The method according to claim 1 , further comprising: The attachment layer is laminated to the abrasive sheet prior to jump cutting the abrasive sheet, wherein the tensioning causes the portion of the attachment layer associated with the slit to tear to form an opening.

12. The method of claim 1 , further comprising fixing the opened abrasive sheet, wherein the fixing results in a fixed open area of ​​an opening of the plurality of openings being at least 10% of the stressed open area of ​​the opening, wherein fixing comprises applying heat or pressure to the opened abrasive sheet.

13. A first web-shaped abrasive article formed by the method of any one of claims 1 to 12, wherein the tensioning creates a first open area and the abrasive sheet has an abrasive grit size.

14. A second web abrasive product formed by the method of any one of claims 1 to 12, wherein the tensioning is different from the first web abrasive product according to claim 13 and produces a second open area different from the first open area, and the second web abrasive product has the same abrasive size, pattern and slit size as the first web abrasive product.

15. A reticulated abrasive article, comprising: a planar coated abrasive sheet comprising a plurality of strands and a plurality of openings formed therein by tensioning a plurality of slits through the coated abrasive sheet, wherein a plurality of bridge regions are formed between ends of the openings in a first direction, wherein the plurality of strands extend diagonally between the bridge regions, wherein the plurality of strands are attached to each other at the bridge regions, wherein at least some of the plurality of strands are separated from each other by the plurality of openings and tensioned such that none of the strands fold when laminated to the attachment layer; and An attachment layer, wherein the coated abrasive sheet is laminated to the attachment layer, wherein the resulting reticulated abrasive article is breathable.

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

17. The web-like abrasive article of claim 15, wherein the coated abrasive sheet has an abrasive major surface and a non-abrasive back major surface, and none of the back major surface is exposed on the abrasive major surface.

18. The webbed abrasive article of claim 15, wherein the coated abrasive sheet comprises: basal layer; A functional layer is disposed on the base layer, wherein the functional layer has abrasive particles having a size smaller than or equal to the P1200 abrasive particle size.

19. The webbed abrasive article of claim 15, wherein the base layer comprises an elastic polymeric material having an elongation at break of at least 30%.

20. The webbed abrasive article of claim 15, wherein the attachment layer has an open area of ​​at least 20%.

21. The webbed abrasive article of claim 15, wherein the plurality of slits form a skipped slit sinusoidal pattern.

22. A kit comprising: The first webbed abrasive article of claim 15, the first webbed abrasive article having an abrasive particle size, a pattern, and a first open area; and A second web abrasive article having the same abrasive particle size and pattern as the first web abrasive article and the same construction as the first web abrasive article, except that the second web abrasive article has a second open area that is different from the first open area, wherein the first web abrasive article and the second web abrasive article have different cut rate or finish characteristics.

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