EP4658450A1 - Article abrasif maillé à motifs fendus et son procédé de fabrication - Google Patents

Article abrasif maillé à motifs fendus et son procédé de fabrication

Info

Publication number
EP4658450A1
EP4658450A1 EP24710231.2A EP24710231A EP4658450A1 EP 4658450 A1 EP4658450 A1 EP 4658450A1 EP 24710231 A EP24710231 A EP 24710231A EP 4658450 A1 EP4658450 A1 EP 4658450A1
Authority
EP
European Patent Office
Prior art keywords
abrasive
abrasive sheet
sheet
slits
mesh
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24710231.2A
Other languages
German (de)
English (en)
Inventor
Christopher J. Carter
Anne C.F. Gold
Paul D. Graham
Silvia G. Guttmann
Jungyong Park
Sally E. LEWIS
Abhishek Srivastava
Tien Yi T.H. WHITING
Michael J. Annen
Priya VENKATRAMAN
Cory M. ARTHUR
Brian K. Daniels
Thomas R. J. Corrigan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Innovative Properties Co
Original Assignee
3M Innovative Properties Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 3M Innovative Properties Co filed Critical 3M Innovative Properties Co
Publication of EP4658450A1 publication Critical patent/EP4658450A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
    • B24D11/001—Manufacture of flexible abrasive materials
    • B24D11/005—Making abrasive webs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
    • B24D11/008—Finishing manufactured abrasive sheets, e.g. cutting, deforming
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D11/00—Constructional features of flexible abrasive materials; Special features in the manufacture of such materials
    • B24D11/02—Backings, e.g. foils, webs, mesh fabrics

Definitions

  • MESH ABRASIVE ARTICLE WITH SLIT PATTERNS BACKGROUND It is very common for dry sanding operations to generate a significant amount of airborne dust. To minimize this airborne dust, it is common to use abrasive discs on a tool while vacuum is drawn through the abrasive disc, from the abrasive side through the backside of the disc, and into a dust-collection system. For this purpose, many abrasives are available with holes converted into them, to facilitate this dust extraction.
  • Aspect of the present disclosure describes a method for producing a mesh abrasive article that involves starting with an abrasive sheet having a base layer that is a continuous impermeable substrate. The sheet is then slit in a pattern to create a slitted abrasive sheet, where the slits penetrate the first surface of the abrasive sheet. The slitted abrasive sheet undergoes tension until it reaches a strain up to a flattenability strain threshold, thereby causing the slits to open up into stressed areas and form a plurality of openings.
  • Additional aspects of the present disclosure relate to a mesh abrasive article made using the aforementioned method.
  • Additional aspects of the present disclosure describe a mesh abrasive article that comprises a planar coated abrasive sheet and an attachment layer.
  • the coated abrasive sheet includes a plurality of strands and a plurality of openings formed by straining a plurality of slits on the sheet.
  • a plurality of bridging regions are formed between end parts of openings in a first direction, and the strands extend diagonally between the plurality of bridging regions. Additionally, 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 straining is done in such a way that none of the strands foldover after laminating.
  • the coated abrasive sheet is laminated onto the attachment layer, which results in an air-permeable mesh abrasive article.
  • FIG. 1 illustrates an abrasive sheet of the subject matter in accordance with one embodiment.
  • FIG. 2 illustrates a slitted abrasive sheet of the subject matter in accordance with one embodiment.
  • FIG. 3 illustrates a slitted abrasive sheet in accordance with one embodiment.
  • FIG. 4 illustrates an opened abrasive sheet in accordance with one embodiment.
  • FIG. 12 illustrates an opened abrasive sheet in accordance with one embodiment.
  • FIG. 5A illustrates a first surface of a mesh abrasive article in accordance with one embodiment.
  • FIG. 5B illustrates a slitted abrasive sheet in accordance with one embodiment.
  • FIG. 6 illustrates a flow chart of a method of making the mesh abrasive article in accordance with one embodiment.
  • FIG. 7 illustrates an apparatus for winding a slitted abrasive sheet in accordance with one embodiment.
  • FIG. 8A, FIG. 8B, FIG. 9A, FIG. 9B illustrate an abrasive sheet having a diamond slit pattern in variety of degrees of size and expansion in accordance with one embodiment.
  • FIG. 8A, FIG. 8B, FIG. 9A, FIG. 9B illustrate an abrasive sheet having a diamond slit pattern in variety of degrees of size and expansion in accordance with one embodiment.
  • FIG. 10A illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 10B illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 11A illustrates a reticulated abrasive article having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 11B illustrates a reticulated abrasive article having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 11A illustrates a reticulated abrasive article having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 11B illustrates a reticulated abrasive article having
  • FIG. 12A illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 12B illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 13A illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 13B illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 13B illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 14A illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 14B illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 15A illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 15B illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 15A illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 15B illustrates a non-diamond slit pattern that provide expansion of the slitted a
  • FIG. 16A illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 16B illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 17A illustrates an aspect of the subject matter in accordance with one embodiment.
  • FIG. 17B illustrates an aspect of the subject matter in accordance with one embodiment.
  • FIG. 18A illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 18A illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 18B illustrates a reticulated abrasive article having three different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 19A illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 19B illustrates a non-diamond slit pattern that provide expansion of the slitted abrasive sheet in at least one direction.
  • FIG. 20A illustrates a reticulated abrasive article having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 20A illustrates a reticulated abrasive article having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 20B illustrates a reticulated abrasive article having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least one direction.
  • FIG. 21A illustrates reticulated abrasive articles having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least two directions.
  • FIG. 21B illustrates reticulated abrasive articles having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least two directions.
  • FIG. 22C illustrates reticulated abrasive articles having a multitude of a plurality of expandable regions that provide expansion of the reticulated abrasive articles in at least two directions, such as radial expansion.
  • FIG. 23A illustrates reticulated abrasive articles having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least two directions.
  • FIG. 23B illustrates reticulated abrasive articles having two different size and/or shape openings that provide expansion of the reticulated abrasive articles in at least two directions.
  • FIG. 24B illustrate reticulated abrasive articles having three different size and/or shape openings that converge to provide expansion of' the reticulated abrasive articles in at least three directions.
  • FIG. 25 illustrates an example mesh abrasive article in accordance with one embodiment. DETAILED DESCRIPTION [0046] Aspects of the present disclosure can relate to a mesh abrasive article created using expandable patterns of slits on a coated abrasive sheet. As the slitted abrasive sheet is strained, the slits expand into openings and form a plurality of strands on the resulting slitted abrasive sheet.
  • the pattern may be a single slit pattern, multi-slit pattern, compound pattern, or combination thereof.
  • the pattern may include skip slits, and the change in height of an abrasive surface (after lamination) to average material thickness of the abrasive sheet ranges from 0.6 to 1.7 when subjected to a strain up to the flattenability strain threshold using the Topographical Profile Method.
  • the tensioning can result in at least one twist in the strands when subjected to strain up to the flattenability strain threshold but no foldovers occur when the slitted abrasive sheet is laminated or flat compressed.
  • no foldovers occur when the slitted abrasive sheet is subjected to strain up to the flattenability strain threshold and flat compression occurs. In one embodiment, less than 5% of the surface area for a plurality of edges for the abrasive sheet protrude outside of an abrasive sheet plane after tensioning.
  • the method may also involve laminating the base layer onto an attachment layer to form the mesh abrasive article.
  • the attachment layer may 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, allowing dust to be removed from an abraded surface through the mesh abrasive article.
  • the resulting mesh abrasive article can have an air permeability of greater than 377 cubic feet per minute per square foot as measured via ASTM D737-18 (2023).
  • the laminating process can 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 direct-attachment (to a backup pad) pressure-sensitive adhesive.
  • Other steps in the method may include winding the slitted abrasive sheet a plurality of times around a core member for tensioning, cutting the mesh abrasive article in a cross-direction and/or machine direction, and fixing the opened abrasive sheet.
  • the abrasive sheet's first surface is a functional layer, such as a structured abrasive, while the second surface is the base layer.
  • the base layer may be a polymeric material such as a stretchable elastic polymer material having an elongation until break of at least 100%, or it may be a coated paper.
  • the tensioning process takes place by winding the slitted abrasive sheet a plurality of times around a core member extending in an axial direction and may occur in a machine direction such that a tensile force on the slitted abrasive sheet causes plastic deformation of the slitted abrasive sheet.
  • the tensile force may be at least 1 pound per square inch.
  • the method may also involve fixing the opened abrasive sheet using heat, pressure, or both. The fixing results in the fixed opened area of an opening from the plurality of openings being at least 10% of the stressed opened area of the opening.
  • the heat may be applied via an in-line oven to fix the plurality of openings, and the applied heat may be at least 120 degrees Celsius and applied via blown hot air.
  • the pressure applied in fixing may be at least 5 kg per linear centimeter and applied with a roll nip.
  • the method also encompasses a mesh abrasive article formed by the process disclosed herein and may include cutting the mesh abrasive article in a cross-direction and/or machine direction.
  • Each of the plurality of slits is a slit when the mesh abrasive article is in an unstressed state, but in a stressed state, at least some of the slits become openings.
  • the disclosed method of making a mesh abrasive article includes providing an abrasive sheet having a continuous impermeable substrate as a base layer.
  • the abrasive sheet has a first surface and a second surface opposite the first surface.
  • the method further includes slitting the abrasive sheet in a pattern and tensioning the slitted abrasive sheet to a strain up to a flattenability strain threshold to create a plurality of openings, forming an opened abrasive sheet.
  • the mesh abrasive article may also involve attaching the base layer of the abrasive sheet onto an attachment layer using adhesive, heat, pressure, or any combination.
  • aspects of the present disclosure can relate to a method of making a mesh abrasive article.
  • the method includes providing an abrasive sheet having a first surface and a second surface opposite the first surface.
  • the abrasive sheet comprises a base layer comprising an elastic polymer material having an elongation until break of at least 100%.
  • the method also includes skip slitting the abrasive sheet in a machine or cross-direction to form a slitted abrasive sheet having a plurality of slits formed therein, the plurality of slits penetrating the first surface.
  • the method includes tensioning the slitted abrasive sheet to form an opened abrasive sheet.
  • the tensioning causes the plurality of slits of the slitted abrasive sheet to form a plurality of openings having a stressed opened area.
  • the tensioning the slitted abrasive sheet occurs by winding the slitted abrasive sheet a plurality of times around a core member extending in an axial direction to form an opened abrasive sheet. The winding occurs in a machine direction such that a tensile force on the slitted abrasive sheet causes plastic deformation of the slitted abrasive sheet.
  • the method also includes fixing the opened abrasive sheet to form the mesh abrasive article.
  • the application of heat can at least partially fix the opened holes to have a fixed opened area.
  • pressure can also be applied to at least partially fix the opened holes.
  • Aspects of the present disclosure also relate to a mesh abrasive article prepared according to the method described herein. [0063] Aspects of the present disclosure relate to a mesh abrasive article comprising a planar coated abrasive sheet and an attachment layer.
  • the coated abrasive sheet includes a plurality of strands and a plurality of openings formed by straining a plurality of slits on the coated abrasive sheet.
  • the bridging regions are formed between end parts of openings in a cross or machine direction, and the plurality of strands extend diagonally between these bridging regions. At least some of the plurality of strands are separated from each other by the plurality of openings and strained such that none of the strands foldover after lamination.
  • the coated abrasive sheet is laminated onto the attachment layer, resulting in an air-permeable mesh abrasive article.
  • the mesh abrasive article has an air permeability of greater than 377 cubic feet per minute per square foot, as measured via ASTM D737-18 (2023).
  • the coated abrasive sheet may have an abrasive major surface and a non-abrasive backside major surface, and none of the backside major surface is exposed on the abrasive major surface.
  • the disclosed mesh abrasive article includes a planar coated abrasive sheet with a plurality of strands and openings formed by straining a plurality of slits.
  • the coated abrasive sheet is laminated onto an attachment layer, resulting in an air-permeable mesh abrasive article that may have a specific air permeability and abrasive major surface.
  • aspects of the present disclosure provide for a kit that comprises a first mesh abrasive article having a specific grit size and first open area, and a second mesh abrasive article with the same grit size but a different second open area.
  • the first and second mesh abrasive articles have different cut rates or finish properties, allowing the user to select the appropriate mesh abrasive article for their specific application.
  • Aspects of the present disclosure relate to a method of making a mesh abrasive article, and apparatus thereof.
  • the method can include pattern slitting a flexible abrasive sheet, tensioning the slitted abrasive sheet to open the slits, and fixing the opened abrasive such that the slits remain at least partially open, thereby forming the mesh abrasive article (which can be a coated abrasive article).
  • the fixing can include applying heat to the opened abrasive sheet at a temperature of at least 120 degrees Celsius.
  • the use of a flexible base layer known in the context of flexible abrasive sheets, was found to be advantageously suited to stretching and not breaking when subjected to tensile force.
  • the mesh abrasive article formed has formed holes useful in dust extraction while maintaining the structural integrity useful in abrading applications.
  • the disclosure proves to be beneficial in manufacturing in several ways. Firstly, the method of creating slits in the abrasive sheet, as opposed to cutting holes or coating mesh with abrasive particles, eliminates the need to remove pips or other debris when converting the abrasive article precursors into slitted counterparts. This can save time and resources in the manufacturing process.
  • a mesh abrasive article made from a slitted abrasive sheet can allow for a flatter abrasive surface which can lead to a finer finish and more abrasive in contact with the work surface.
  • the slits can be produced by mechanically cutting the abrasive sheet or by using a laser, which can be more efficient and precise than other methods.
  • the slits can be adjusted according to the application, allowing for a more versatile product.
  • FIG. 1 illustrates an abrasive article 101 used to illustrate the construction of an example abrasive article.
  • the abrasive article 101 can be a coated abrasive article having an attachment layer.
  • Various examples of abrasive article 101 are commercially available as film discs under the trade designation “Hookit” from 3M (Saint Paul, MN).
  • the abrasive article 101 can include a functional layer 102, which can be a coated abrasive layer used to abrade materials.
  • the functional layer 102 can further include a supersize coating.
  • the functional layer 102 can be disposed on a base layer 104.
  • the base layer 104 can be formed from a material configured to deform in response to a tensile force while having some toughness to provide integrity to the functional layer 102.
  • the base layer 104 comprises an elastomeric film.
  • the elastomeric film may be monolithic or may itself be a composite film having multiple layers produced by coextrusion, heat lamination, or adhesive bonding.
  • Examples of materials that may be used in the elastomeric film include polyolefin, polyester (e.g., those available under the trade designation "HYTREL” from E.I. du Pont de Nemours & Co., Wilmington, Delaware), polyamide, styrene/butadiene copolymer (e.g., those available under the trade designation "KRATON” from Kraton Polymers, Houston, Texas), and polyurethane elastomers (e.g., those polyurethane elastomers available under the trade designation "ESTANE 5701" and “ESTANE 5702” and “ESTANE 58887”); chloroprene rubber, ethylene/propylene rubbers, polybutadiene rubber, polyisoprene rubber, natural or synthetic rubber, butyl rubber, silicone rubber, or EPDM rubber; and combinations thereof.
  • polyolefin polyester
  • polyester e.g., those available under the trade designation "HYTREL” from E.I. du Pont de
  • useful elastomeric films include those described in U.S. Patent 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 RE33353 (Heinecke). Still other useful elastomeric films include pressure sensitive adhesive coated polyurethane elastomer films, commercially available from 3M Company, St.
  • the base layer 104 may be made from a polymer derived from: 0-50 wt% carboxylic acid resins (for example, acrylate acid); 0-50 wt% of alkyl acrylates, alkyl methacrylates, and alkyl ethacrylates (for example, ethyl acrylate); 0-50 wt% unsaturated acetate (for example, vinyl acetate); and ⁇ -olefins (for example, ethylene) making up the balance.
  • carboxylic acid resins for example, acrylate acid
  • alkyl acrylates alkyl methacrylates
  • alkyl ethacrylates for example, ethyl acrylate
  • unsaturated acetate for example, vinyl acetate
  • ⁇ -olefins for example, ethylene
  • the base layer 104 has a percent elongation at break of at least 100 percent, at least 200 percent, at least 300 percent, at least 400 percent, or at least 500 percent, as measured under ambient conditions.
  • the base layer 104 has a percent elongation at break of at most 1000 percent, at most 800 percent, at most 700 percent, at most 600 percent, or at most 500 percent, as measured under ambient conditions.
  • 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 ten percent of the gauge length per minute.
  • non-tacky refers to a material that satisfies the Dahlquist criterion for a non-tacky substance, implying it has a storage modulus (G') of less than about 3 ⁇ 10 5 pascals (measured at 10 radians/second at ambient temperature), described in U.S. Patent No. 6,884,504 (Liu et al.). Also cited in: Dahlquist Criterion, "Handbook of Pressure Sensitive Adhesive Technology," 2nd ed. (1989), pp. 172-176.
  • Preferred materials for the base layer 104 can have an elastic modulus of between 5 and 20,000 MPa, or alternatively between 10 and 10,000 MPa, or alternatively from 20 to 5,000 MPa, or alternatively from 30 to 1,000 MPa, or alternatively from 30 to 500 MPa.
  • One way to measure the elastic modulus is to expose a cross-section of the layer and perform indentation testing.
  • the upper glass transition temperature Tg of the base layer 104 is chosen to be higher than the working temperature of the functional layer 102 to reduce the possibility of relaxation due to heat generated by sanding which could distort the material. In one embodiment, this can be achieved by blending various polymers with different glass transition temperatures.
  • a fused silica calibration standard (having a nominal E of 72 GPa) can be tested before and after sample testing to verify tip integrity. All testing can be conducted on an Aglient G200 nanoindenter with DCM head and Berkovich diamond probe at a constant strain rate of 0.05 s -1 with an assumed Poisson ratio of 0.3. Sample cross-sections can be exposed via microtoming, mounting in one inch diameter epoxy pucks and subsequently polishing to a final finish with 0.1 ⁇ m diamond lapping film.
  • test parameters may be used: 1) surface approach distance 5000 nm; 2) surface approach velocity 30 nm/s; 3) harmonic amplitude 1 nm; 4) harmonic oscillation 75 Hz; 5) depth set point 200 nm; 6) surface find contact stiffness 200 N/m. In some cases, the testing may need to continue past the 200 nm set point, if a steady-state has not been reached.
  • Preferred materials for the base layer 104 can have a hardness of between 1 and 2,000 MPa, or alternatively between 2 and 1,000 MPa, or alternatively from 4 to 500 MPa, or alternatively from 5 to 100 MPa, or alternatively from 5 to 30 MPa. This testing can be performed used the indentation method described above.
  • the base layer 104 can be formed of coated paper, or polymeric materials that are continuous impermeable substrates.
  • a continuous impermeable substrate would be unbroken (prior to slitting) and would generally exclude uncoated woven and non-woven substrates.
  • the base layer 104 preferably has a thickness that is generally uniform across its major surfaces.
  • the average thickness of the base layer 104 may be at least 50 micrometers, at least 60 micrometers, at least 70 micrometers, at least 90 micrometers, at least 100 micrometers, or at least 120 micrometers. On the upper end, the average thickness may be at most 300 micrometers, or at most 150 micrometers.
  • the base layer 104 may be chemically primed or otherwise surface treated, for example by corona treatment, ultraviolet radiation treatment, electron beam treatment, flame treatment, or surface roughening.
  • aspects of the present disclosure relate to a base layer 104 with an elastic primer/make layer disposed thereon which is further overlain with a conventional coated abrasive formulation in the functional layer 102.
  • This continuous elastic primer layer can prevent the abrasive in the functional layer 102 from shelling during the tensioning process.
  • the base layer 104 can have an optional adhesive layer 106 used to attach the attachment layer 108 thereon.
  • the adhesive layer 106 can be any moisture curable adhesive.
  • the adhesive layer 106 can be used as a spray adhesive to allow the fabric to both cover the holes whilst remaining porous enough to allow ventilation of dust from the face-side. It is suggested that a starved die or gravure-coated moisture-curing polyurethane adhesive will be a better way to achieve this lamination.
  • the adhesive should become non-tacky during the cooling, drying, or curing process to prevent dust attachment and consequent blocking of the loop fabric.
  • the attachment layer 108 can be a layer used to attach the abrasive article 101 to a sanding tool.
  • the attachment layer 108 is a knit loop structure corresponding to a hook-and-loop style system.
  • the attachment layer 108 can be the adhesive layer 106.
  • the attachment layer 108 can include a pressure sensitive adhesive for attaching the abrasive article 101 to a separate backup pad such as that commercially available as an adhesive-based film abrasive under the trade designation "Stikit”.
  • the attachment layer 108 can be an adhesive that attaches the abrasive article 101 to a substrate.
  • the substrate can include foam (such as a sanding block) or another abrasive sheet 101 to form a double-abrasive.
  • the abrasive article 101 can have a first surface 110 and a second surface 112.
  • the first surface 110 can correspond to the functional layer 102 and the second surface 112 can correspond to the attachment layer 108.
  • functional layer 102 covers no greater than about 40%, no greater than about 50%, no greater than about 60%, no greater than about 70%, no greater than about 80%, no greater than about 90%, no greater than 95% or even no greater than about 98% of the first major surface of the attachment layer 108.
  • 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 instances, this means that although edges of the adhesive layer 106 substantially overlap with edges of the attachment layer 108, as shown in FIG.
  • a slitted abrasive sheet 200 is shown that shows an example construction where the abrasive article 101 (including an attachment layer) is slit through the attachment layer 108.
  • the attachment layer 108 can have a plurality of slits formed therein (exemplary slit 202 and slit 204 are shown but the plurality of slits can include either type of slit or a combination of both slits).
  • a slitted abrasive sheet can be produced without the attachment layer 108, wherein an abrasive sheet (without attachment layer 108) is slit in a pattern and then laminated onto an attachment layer 108.
  • a slitted abrasive sheet can be produced without the attachment layer 108, wherein an abrasive sheet (without attachment layer 108) is slit in a pattern and then laminated onto an attachment layer 108 in a separate step.
  • the slitted abrasive sheet 200 has slits 202 and slit 204 extending across the first surface 110.
  • the slit 202 fully penetrates through the functional layer 102, the base layer 104, the optional adhesive layer 106, and at least partially through the attachment layer 108.
  • the slit 202 may extend at least 10 percent, at least 20 percent, at least 30 percent, at least 40 percent, at least 50 percent, at least 60 percent, at least 70 percent, at least 80 percent, or at least 90 percent through the attachment layer 108 but not extend through the attachment layer 108.
  • the slit 204 may also extend entirely through the entire slitted abrasive sheet 200, including the attachment layer 108.
  • the slit 204 can penetrate all the layers (functional layer 102, base layer 104, adhesive layer 106, and attachment layer 108) from the first surface 110 through the second surface 112.
  • the slitted abrasive sheet 200 has a plurality of slits that are evenly spaced from each other and extend across most if not all of the major first surface 110.
  • the plurality of slits preferably have a maximum width that is essentially zero or near zero when the slitted abrasive sheet 200 is in a relaxed configuration, although a finite width is shown in FIG. 2 for illustrative purposes.
  • Each slit has a pair of matching and generally contiguous slit surfaces.
  • the slit surfaces may touch each other along the entire depth dimension of the slit (as possible in slit 204), at various points along the depth dimension, or at the base (i.e. the deepest point) of the slit (as possible in slit 202).
  • disposing the plurality of slits on the slitted abrasive sheet 200 is also advantageous from a manufacturing perspective because there is no need to remove pips or other debris when converting the abrasive article precursors (such as abrasive sheet 101) into slitted counterparts.
  • 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 conversion using a laser.
  • the slit (not shown) can extend only through the functional layer 102 and at least part of the base layer 104. In one embodiment, the slit can extend all the way through the base layer 104 but not the adhesive layer 106 or attachment layer 108.
  • FIG. 3 illustrates another view of the slit 204.
  • the slit 204 can have plurality of slit dimensions, such as dimension 302 in the cross-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 touching in this relaxed configuration.
  • a plurality of edges can exist on the slitted abrasive sheet 200.
  • the edges 306, 308 can form the strand of the opened abrasive sheet when the slitted abrasive sheet 200 is in a stressed state.
  • an opened abrasive sheet 400 can be formed when a tensile force is applied in at least one direction (e.g., machine direction 406 is shown) which causes a slit 204 (shown by its previous location in FIG.
  • the opening 402 can be formed from the edges 306, 308 of the slit 204.
  • the opening 402 can have the shape of a rhomboid or vesica piscis.
  • the opening 402 can have a major diagonal 404 and a minor diagonal 408, where both are less than the dimension 302. [0102]
  • the dimensions of the opening 402 can define an opened area 414 of the opening 402.
  • the opened area 414 of the opening 402 can vary depending on the state of the manufacturing step.
  • the opened area 414 can vary from a stressed opened area (which may be a maximum opened area) to fixed opened area to an unstressed opened area.
  • the unstressed opened area can be no greater than 40 percent, no greater than 30 percent, no greater than 20 percent, no greater than 15 percent, no greater than 10 percent, no greater than 5 percent of the stressed opened area.
  • the fixed opened area can be at least 5 percent, at least 10 percent, at least 15 percent, at least 20 percent, at least 25 percent, at least 30 percent, at least 35 percent, at least 40 percent, at least 45 percent, at least 50 percent, at least 60 percent, at least 70 percent, at least 80 percent, or at least 90 percent of the stressed opened area.
  • the fixed opened area is at least 5 percent, at least 10 percent, at least 15 percent, at least 20 percent, at least 25 percent, at least 30 percent, at least 35 percent, at least 40 percent, at least 45 percent, at least 50 percent, at least 60 percent, at least 70 percent, at least 80 percent, at least 90 percent, at least 100 percent, or at least 150 percent greater than the unstressed opened area.
  • the fixed opened 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 opened area of the (same) abrasive sheet.
  • the opened abrasive sheet 400 is shown in a skip slit or a staggered pattern where a diagonal 408 in the machine direction 406 of one opening 402 in one row 410 is not aligned with a diagonal of another opening in an adjacent row 412.
  • the edges 306, 308 can be formed adjacent to the slit 204 from the plurality of slits.
  • the pattern of the plurality of slits can be arranged such that, when under tension up to the flattenability strain threshold, no greater than 15%, no greater than 10%, or no greater than 5% of the surface area for a plurality of edges for the abrasive sheet protrudes outside of the abrasive sheet plane.
  • a twist can form that has some portion of the edges protrude beyond the plane and lift.
  • a foldover does not necessarily form from the twist since a lamination process or flat compression can flatten a twist if the twist does not protrude significantly.
  • the tensioning results in at least one twist in the strands of the opened abrasive sheet when subjected to strain up to the flattenability strain threshold and the laminating does not result in any foldovers.
  • the edges 306, 308 of the slit 204 (which can also be the strands), when under tension or strain up to the flattenability strain threshold, do not protrude past the abrasive sheet plane.
  • no twists are formed when the slitted abrasive sheet or opened abrasive sheet is subjected to strain up to the flattenability strain threshold, and no foldovers are formed.
  • FIG. 5A and 5B illustrate a skip slit pattern of a plurality of slits.
  • the slits as shown are extending in the cross-direction. However, it is understood that the plurality of slits can be arranged to extend in the machine direction, thereby allowing tension in the cross-direction to expand the slitted abrasive sheet.
  • a plurality of openings 86 which penetrate in the thickness direction of the abrasive sheet 84a are formed in the abrasive sheet 84a (which is comparable to slitted abrasive sheet 200) .
  • the openings 16 are formed by winding the abrasive sheet 84 using the apparatus illustrated in FIG.
  • the openings 86 appear on the first surface 83c of the functional layer 83.
  • the openings 86 have a slit shape that extends in a first direction D1.
  • the openings 86 have a shape such as an oval, or vesica piscis shape or a substantially rectangular shape including rhombus shapes, because they are originally created in a slit form and formed into the slits 6 by widening them.
  • the openings 86 have end parts 86a on the two end sides in the first direction D1.
  • the end parts 86a correspond to the two ends of the slits 6 in the first direction D1 prior to widening.
  • the openings 86 are provided at a prescribed pitch in the first direction D1, and are provided at a prescribed pitch in a second direction D2 perpendicular to the first direction D1.
  • the first direction D1 corresponds to the axial direction in which the center axis line CL extends in the cross-direction.
  • the openings formed can be a random configuration. For example, variations in the tension in both the cross-direction and machine direction can produce openings 86 having a random shape and orientation.
  • the second direction D2 corresponds to the winding direction or the machine direction, which is the direction in which the abrasive sheet is wound.
  • the abrasive sheet 84 which constitutes the functional layer 83 can be segmented into a plurality of regions 3 extending in the first direction D1 and arranged in the second direction.
  • a boundary 4 is formed extending in the first direction D1 between a pair of regions 3.
  • FIG. 5B virtual lines corresponding to some of the boundaries 4 are shown. When viewed from the cross- direction, the boundaries 4 form straight lines which extend straight in the first direction D1.
  • a boundary 4 is defined as a reference line set for the openings 86 that are aligned at a prescribed pitch in the first direction D1, among the plurality of openings 86.
  • the boundary 4 as a reference line is a line set so as to pass through the center position of each opening 86 aligned in the first direction D1 and to pass through the end parts 86a.
  • the positions of the end parts 86a may deviate and the virtual lines of the boundaries 4 do not have to completely overlap the end parts 86a due to manufacturing error.
  • the “boundary” corresponds to that virtual line.
  • a “region” is a portion virtually delimited by a boundary 4 and a boundary 4.
  • the boundary 4 is defined by a virtual line that passes through the linear slits 6, as illustrated in FIG. 5B.
  • the region 3 is set as a region in the direction of extension of the abrasive sheet 84 where no slits 6 are formed.
  • the boundary 4 is set based on the openings 86 aligned in the first direction D1.
  • a plurality of openings 86 are formed extending in the first direction at the boundaries 4.
  • a plurality of openings 86 are disposed separated from each other in the first direction D1. The position at which the openings 86 are separated can function as a connecting part 7 which connects the regions 3 to each other.
  • a pair of regions 3 adjoining in the second direction D2 are mutually connected by a connecting part 7 (or bridging region) formed between openings 86.
  • a “connecting part” corresponds to a portion on the virtual line of the boundaries 4 where no openings 86 are formed.
  • the term connecting part can also be referred to as a bridging region herein.
  • the connecting part 7 is a portion affixed such that when a force is applied so as to widen each region 3 in the second direction, the opening thereof does not widen like the openings 86 and adjoining regions 3 do not separate from each other.
  • the space between the openings 86 in the diagonal direction can be referred to as a strand.
  • the strand 5 can be from the midpoint of the connecting part 7 to the midpoint of a kitty-corner connecting part 7 on a different column or boundary 4.
  • the strands 5 can be formed from the edge adjacent to a slit between columns in the machine direction and the connecting part 7 can be formed from the parts between slits within the same column in the first direction D1.
  • the opening 86 of a boundary 4 formed on one side in the second direction D2 and the opening 86 of the boundary 4 formed on the other side, relative to a region 3, are disposed at different positions in the first direction D1. Specifically, for mutually adjoining boundaries 4, the opening 86 of one of the boundaries and the opening 86 of the other boundary 4 have a staggered positional relationship.
  • a structure in which a plurality of openings 86 (slits 6 before winding) are disposed in a staggered manner is sometimes called “skipping slits.”
  • the opening 86 and the boundary 4 are disposed at the same position.
  • the pair of boundaries 4 are set to form a staggered pattern of openings 86.
  • the dimensions of the region 3, opening 86, and connecting part 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 from 1 to 100 mm or from 5 to 50 mm.
  • FIG. 6 illustrates a flowchart of a method 600 of making a mesh abrasive article. Reference to the apparatus in FIG. 7 will also be made.
  • an abrasive sheet can be provided. As described earlier, the abrasive sheet can be commercially available from 3M which includes the attachment layer. The abrasive sheet can be provided as a jumbo roll and any of block 604, block 606, or block 614 can be performed.
  • the abrasive sheet can have a plurality of slits formed therein which penetrate in the thickness direction.
  • a slitted abrasive sheet in which a plurality of slits arranged in a staggered manner (i.e., skip slits) are prepared as illustrated in FIG. 5B.
  • the slitted abrasive sheet can be formed as a roll to be further processed at a later time or continuously in a roll-to-roll manufacturing method.
  • the base layer contains a plurality of cuts or slits arrayed in a pattern, in some embodiments the pattern may be random, in other embodiments, the pattern is arrayed along at least one axis.
  • the two-dimensional surface of the base layer can be viewed as having two primary orthogonal axes, frequently referred to as an x axis and a y axis. Because of how films are made, often the x axis is described as the “Machine Direction”, or MD and the orthogonal y axis is described as the “Cross Direction” or CD.
  • the plurality of slits are arrayed in a pattern along the Machine Direction.
  • the lengths of the plurality of cuts are aligned along the Machine Direction of the base layer.
  • the plurality of slits are aligned along the cross-direction.
  • the plurality of slits arrayed in a pattern are gaps, but these gaps are essentially not visible to the naked eye when the base layer is in an unstressed state. At least some of the gaps become visible to the naked eye when the abrasive article is in a stressed state.
  • stressed state comprises stretching, bending or a combination thereof. Because the slits are very thin (i.e. have essentially no width) in the unstressed state, they are typically described by their length and a depth.
  • the cut extends through the full thickness of the base layer, so the depth is the same as the thickness of the base layer.
  • One parameter that can be descriptive of the relationship of the length to the width of the cut is the aspect ratio.
  • the term “aspect ratio” is typically used to describe particles, but as used herein it is used to describe hole size or void regions where material is not present.
  • the aspect ratio (the ratio of length to width) for the slits is greater than 1000. Upon application of a stress, the aspect ratio for the slits decreases.
  • An example of a suitable cut is one that is 1 centimeter long and 5 micrometers wide. [0126]
  • the plurality of slits may include at least some slits that are continuous.
  • the slits may be more complex than the simple linear shape described above.
  • the slits may have a variety of two-dimensional shapes such as crosses, asterisks, waves, chevrons, letters, numbers, and the like.
  • the slits are arrayed in a pattern along the Machine Direction of the substrate. Often the slits are formed by a process known as “skip slitting”. In this process, a series of discontinuous slits are formed in the substrate in a linear manner.
  • the multiple strands and interrupted slits extend in the first direction, creating a plane, and are attached to each other at the intact bridging regions that are staggered in a second direction transverse to the first direction.
  • the thickness of the skip slit sheet, and consequently the thickness of multiple strands can be up to about 1 mm. In some embodiments, the thickness of the skip slit sheet or strands can be up to about 400, 250, 150, or 100 micrometers. In some embodiments, the thickness of the skip slit sheet or strands can be in a range from 30 to about 225 micrometers, from about 50 to about 200 micrometers, or from about 100 to about 150 micrometers.
  • the skip slit sheet's bridging regions, in a particular direction of the interrupted slits, can have a length of at least 0.5mm, 0.75mm, or 1 mm.
  • Spreading can be carried out to increase the width (e.g., in the cross-web direction) of the skip slit sheet in the CD to an extent sufficient such there are minimal strands twisting out-of-plane or onto itself such that no foldovers occur after lamination.
  • Increasing the width of the skip slit sheet by at least 5 percent can be sufficient, depending on the composition of the sheet base layer, sheet's thickness, the length of the slit portions of interrupted slits, the length of the bridging regions, and the distance between slits.
  • the width of the skip slit sheet can be increased at least 10, 15, 20, 25, 30, 40, or 50 percent.
  • the width of the skip slit sheet can be increased by up to 100 percent or more, depending on various factors.
  • the plurality of slits is arrayed in a pattern along more than one axis. By this it is meant that at least some of the slits have lengths that are not aligned with the Machine Direction of the base layer but are offset from alignment by an angle of up to 90°. Lengths that are offset from alignment with the MD of the base layer by 90° are considered aligned in the Cross Direction.
  • the plurality of slits can be made in a number of different ways as long as the method does not involve removing substantial amounts of material from the base layer and the slits form gaps that are essentially not visible to the naked eye in the unstressed state and at least some of gaps become visible to the naked eye when the abrasive article is in a stressed state.
  • the methods are those in which the slits are introduced into the base layer when the layer is formed for example by extrusion, molding, machining and the like.
  • slits are introduced into the base layer 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 waterjet, or a laser beam, or by stamping using a stamping tool.
  • the slits are made by feeding the base layer into a nip containing a rotary die blade and an anvil such that the die cuts through the base layer to form the cut pattern.
  • a slit is a cut through material with minimal thickness.
  • forming techniques may involve the removal of material, or the formation of a gap between the edges of a slit.
  • a laser cutter can ablate some material to create a slit
  • a router can cut away material to create the slit
  • even crush cutting can create some deformation on the edges of the material that forms a physical gap.
  • Molding techniques require material between opposing faces of the slit, creating a gap or kerf at the slit.
  • the gap or kerf of the slit will be less than the thickness of the material.
  • a slit pattern cut into paper that is .007 inch (178 micrometers) thick might have slits with a gap that is approximately .007 inch (178 micrometers) or less.
  • the physical gap of the slit could be increased to a factor that is many times larger than the thickness of the substrate.
  • the slits are formed in the backing layer in such a way as to minimize the removal of material. In this way, the slits are not visible when the article is in an unstressed state, and thus do not form permanent openings in the backing.
  • the height differential to material thickness ratio can be within a certain range.
  • the value can 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 the Topographical Profile Method.
  • the range can be from 0.6 to 1.7.
  • the slitted abrasive sheet can be tensioned (i.e., the slitted abrasive sheet is in a stressed state which can cause strain) which can form the opened abrasive sheet.
  • the tensioning can refer to stretching or straining the slitted abrasive sheet and the term “straining” can be used interchangeably with “tensioning.”
  • the tensioning can be accomplished using a variety of techniques such as winding one end of the slitted abrasive sheet a plurality of times around a core member extending in an axial direction.
  • the winding can result in strain being applied to the slitted abrasive sheet up to the flattenability strain threshold.
  • the strain can also be applied in the cross-direction to tension the slitted abrasive sheet perpendicular to the machine direction.
  • the winding can occur in a machine direction such that a tensile force applied to the slitted abrasive sheet causes plastic and/or elastic deformation of the slitted abrasive sheet and further causes the plurality of slits of the slitted abrasive sheet to form a plurality of openings as described in FIG. 4 and FIG. 5A.
  • the flattenability strain threshold can depend on the material used and the pattern of the plurality of slits. As an example, as little one pound per square inch (PSI)(6.8 kPa) could open the plurality of slits in a skip slit configuration. In one embodiment, 5 PSI (34.4 kPa) or 50 PSI (68 kPa) can be used to sufficiently open the slits into a fully opened opening having a stressed opened area. [0140] In one embodiment, the flattenability strain threshold can be reached at point where the maximum percent open area in the opened abrasive sheet is achieved without foldovers after lamination.
  • the tensioning can use a tentering process in which a set of clips fasten to both sides of a slitted abrasive sheet and the clips move away from each other in opposite directions, thus forming the plurality of openings each having a stressed opened area.
  • the tensioning in block 606 can use a web handling process in which the slitted abrasive sheet is accelerated by controlling the relative speed of adjacent nip rolls or pull rolls thus causing tension between two points in the slitted abrasive sheet.
  • block 606 can occur at an elevated stretch temperature.
  • tensioning can occur at higher than ambient conditions to allow for a greater degree of opening of the plurality of slits when forming the opening with a stressed opened area.
  • the elevated temperature can be above the highest glass transition temperature of the base layer.
  • the stretch 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.
  • a step of winding an abrasive sheet 84 a plurality of times around the core member 82 extending in the axial direction is executed.
  • dry winding is performed by the winding apparatus 50 illustrated in FIG. 7.
  • the winding apparatus 50 includes a part that holds a roll body 51 of the abrasive sheet 84 in which slits 6 have been formed.
  • the winding apparatus 50 feeds the abrasive sheet 84 from the roll body 51 and guides the abrasive sheet 84 to a winding part 52 via a plurality of rollers.
  • the winding part 52 winds the abrasive sheet 84 around the core member 82 a plurality of times to form a roll body 54.
  • the abrasive sheet 84 is wound in a state where tensile force so as to widen the slits 6 (refer to FIG. 5A) is applied. Also note that the wound abrasive sheet 84 may be affixed by a prescribed method so as to stay on the roll body 54. [0145]
  • the tensile force can be set based on the tensioner 704 applied to the abrasive sheet 84.
  • the tensioner 704 in combination with the winding of the core member 12
  • the tensile force can be measured at any two points in the sheet within the region 706 (e.g., after unwinding from the roll body 51 but before any fixing or attachment of an attachment layer).
  • the forming of the plurality of openings from the plurality of slits can form the opened abrasive sheet in region 706.
  • the abrasive sheet 84 can be further stretched such that the plurality of openings become larger and form a maximum open area from the borders of the plurality of slits.
  • the opened area of one or more of the plurality of openings can be a stressed opened area that occurs adjacent the roll body 51 (at region 710) as the tensile force is applied to the slitted abrasive sheet.
  • the opened abrasive sheet formed in block 606 can be fixed using a fixing process to the plurality of openings.
  • the fixing in block 608 can occur to the opened abrasive sheet such that at least some of the plurality of openings retain at least 10% of their stressed opened area when having the unstressed opened area.
  • the opened abrasive sheet becomes the mesh abrasive article.
  • the fixing can include various processes such as in block 610, block 612, block 614 which are not meant to be exhaustive.
  • Block 608 can include any combination of block 610, block 612, and block 614.
  • fixing can include applying both heat and pressure using one or more components of a manufacturing apparatus (e.g., winding apparatus 50).
  • a manufacturing apparatus e.g., winding apparatus 50.
  • heat can be applied to the opened abrasive sheet to mitigate any elastic deformation in the opened abrasive sheet.
  • the heat can be applied in an in-line oven 708 that also at least partially retains/fix at least some of the plurality of openings when the stressed opened area of an opening is reverted to a fixed opened area.
  • the heat can be applied via forced blown hot air.
  • the applied heat 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 can occur separately from the elevated stretch temperature in block 606 described herein.
  • the winding apparatus 50 can apply pressure to the opened abrasive sheet to form the mesh abrasive article.
  • the pressure applied can be applied with at least one roller (e.g., using roll nip 702).
  • the roll nip 702 can subject the opened abrasive sheet to heat and/or pressure (e.g., with heated rollers) and can fix the openings such that elastic forces do not cause the plurality of openings to revert back to a plurality of slits.
  • the pressure can be applied using two flat platens.
  • 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.
  • any number of roll nips 702 are possible.
  • the time that the abrasive sheet 84 is exposed to the applied heat and/or applied pressure can be no greater than 10 seconds, no greater than 30 seconds, no greater than 45 seconds, or no greater than 1 minute.
  • the opened abrasive sheet can be flat pressed to fix the openings.
  • the fixing can also include block 614 which includes applying a carrier liner to the non- functional side of the opened abrasive sheet.
  • the carrier liner can provide an additional surface to fixing the opened openings.
  • the carrier liner can be commercially obtained under the trade designation 602197 PET FILM from 3M ( Saint Paul, MN).
  • one or more of block 610, block 612, or block 614 can be performed concurrently or simultaneously within method 600.
  • the heat can be applied simultaneously with the pressure, and/or the carrier liner.
  • the abrasive sheet 84 can be allowed to cool and be collected on the roll body 54.
  • the pressed abrasive sheet can be quenched at a temperature below the glass transition temperature of the base layer to fixing the stressed state configuration.
  • the abrasive sheet can be attached to an attachment layer.
  • the base layer of the unslit abrasive sheet can be attached to the attachment layer prior to slitting the abrasive sheet in block 604.
  • the attaching can be performed by lamination of the opened abrasive sheet and the attachment layer (such as a hook and loop fastener).
  • Lamination refers to a process of attaching two or more layers of material (e.g., an opened abrasive sheet and an attachment layer) together by means of heat, pressure, or adhesive which can be further described herein.
  • the base layer of the opened abrasive sheet can be (directly) laminated onto the attachment layer (e.g., without the use of a release liner intermediate).
  • the lamination process of the functional layer onto an attachment layer typically begins with the preparation of both layers.
  • the attachment layer can be a pressure-sensitive adhesive, a hook and loop material, or other mechanical fastening means.
  • the two layers can be aligned and compressed together using a laminating apparatus, which can apply heat and pressure to the functional and attachment layers similar to block 608.
  • the applied pressure can occur at lower pressures than 1 MPa, such as at least 0.1 MPa.
  • FIG. 7 there is no lamination process shown, but a separate sheet of attachment layer can be introduced just before line oven 708.
  • the lamination process can be achieved using a variety of techniques, including hot melt, solvent-based, and water-based adhesives. Additionally, variations in the lamination process can include the use of release liners to allow for easier handling and storage of the abrasive sheets prior to use.
  • the attachment layer can be air permeable.
  • resulting mesh abrasive article or the attachment later can have an air permeability of greater than 100, 200, 300 or greater than 377 cubic feet per minute per square foot as measured via ASTM D737-18 (2023).
  • the attachment layer can be a mesh or net backing.
  • the mesh backing can be distinguished from other fabrics based on the size of the holes formed therein.
  • the holes in the mesh backing can be formed by the yarns (if knitted or woven) or by the polymer vertical and horizontal strands (if extruded).
  • the holes can be of varying size due to the nature of knitted articles.
  • the mesh backing 102 can have an average size of 0.5 square millimeters.
  • 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%, 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 mesh backing can also include a sizing agent. [0163] If the mesh backing is a fabric (either woven fabric, nonwoven, or knitted fabric), then the fabric can have the following properties. Various fabric mesh backings can be commercially available from Sitip S.p.A. (Cene, Italy) or Scott and Fyfe Ltd. (Tayport, UK).
  • the mesh backing can have a yarn thickness of at least 100 micrometers, at least 150 micrometers, at least 300 micrometers, at least 300 micrometers, or at least 350 micrometers.
  • the yarn can have a total denier of no greater than 3000 deniers, no greater than 1000 deniers, no greater than 500 deniers.
  • the yarn can have a breaking tenacity of at least 300 mN/tex as measured by ASTM D2256.
  • the mesh backing can also have a fabric weight of no greater than 300 gsm (gram per square meter), no greater than 220 gsm, or no greater than 120 gsm.
  • the mesh backing 102 can have a fabric weight of at least 40 gsm.
  • the mesh backing can be mostly planar, and a plane of mesh backing can be established using a Kawabata evaluation system for surface friction and roughness.
  • the attachment layer is planar and flat.
  • "flat” or “planar” refers to the characteristic of the fabric's surface when it does not have any visible lumps, bumps, or ridges or is otherwise not configured to follow the contours of a body. Flatness in this context results from the even distribution of the yarns used to create the mesh fabric, without any waves or thick areas that could cause unevenness.
  • the plane can be established based on a majority of surface area or cross-sectional area of a yarn or other material in a single plane. For example, if a fabric has 50% of the solid surface area in a first plane, but 30% of the solid surface area in a second plane, then the first plane can be the reference plane. Thus, the loops (if knitted) can be raised relative to the reference plane.
  • the reference plane can be generally parallel to a flat surface on which the mesh backing rests.
  • the plane of a woven fabric can be established by the weft.
  • the laminating in block 615 can include applying an adhesive to the base layer or the attachment layer and applying pressure or heat to the base layer or the attachment layer.
  • the winding apparatus 50 can further cut/package the abrasive sheet 84. Additional processing in block 616 can include converting steps such as cutting the roll body 54 into smaller units.
  • the mesh abrasive article can be cut in the cross-direction and/or machine direction to form different form factors.
  • FIGS. 8-24 illustrate a range of slit patterns, with the "A" figures showing the film in slit and unstressed/unreticulated state, and with the "B" figures showing the same film patterns in a stressed/reticulated state.
  • FIGs 8, 9, 10, 13, 15,16, 17, and 19 there is shown a reticulated abrasive article 10 having a longitudinal direction and a width direction, and including a plurality of strands 16 of an abrasive material attached to one another at bridging or connecting regions 18 in the abrasive material and separable from one another between the bridging regions 18 to provide openings 22 in the abrasive material, where the openings 22 provide a variably expandable area, also where 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 also where the reticulated abrasive article 10 is expandable in at least one direction.
  • the direction of expansion is the longitudinal direction, such that expansion occurs along the axis parallel to the longitudinal dimension 12 of the reticulated abrasive article 10.
  • the direction of expansion is the width direction such that expansion occurs along the axis parallel to the width dimension 14 of the reticulated abrasive article 10.
  • 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 FIGs 8, 9, 17, the openings 22 have a diamond shape. In some embodiments, such as those depicted in FIGs 10, 13, 15, 16, 19, the openings have a shape other than a diamond shape.
  • FIG. 8- 9 can be considered “simple slits,” which are defined herein as slits having exactly two terminal ends.
  • FIGS. 11-14, 19, 20, in some embodiments the presently disclosed reticulated abrasive articles 10 provide two sets of openings for more complex expandability. For example, as shown in FIG.
  • the presently disclosed reticulated abrasive sheets 10 provide more than two sets of openings for more complex expandability.
  • FIG. 12A, FIG. 14A, FIG. 18A there are multi- dimensioned or shaped slits 11, 21, 31 or perforations in the reticulated abrasive sheet 10 that result- in the openings 22, 23 shown in FIG. 12B, FIG. 14B, FIG. 18B.
  • the reticulated abrasive sheet 10 can be described by the relation of one slit to another slit before the article is stretched and after the article is stretched and it has returned, at least in part, to its pre-stretched state. If not specified, any degree of overlap or lack thereof is referring at least to the degree of overlap that is measured before a reticulated abrasive sheet has been stretched, e.g., in a pre-stretched state. Specifically, the degree of overlap of slits that are offset with respect to an axis perpendicular to the longitudinal dimension 12 (or offset with respect to an axis perpendicular to the width dimension).
  • the abrasive sheet 10 that is depicted in FIG. 12 can be a multi-slit pattern.
  • a “multi-slit pattern” is defined as a pattern of individual slits that form a first set of adjacent rows across the transverse (i.e., cross) direction of the sheet, where the individual slits within the first set of adjacent rows are aligned in the transverse direction.
  • the first set of adjacent rows form a repeating pattern with at least a second row along the axial length of the sheet (i.e., machine direction), where the slits in the first set of adjacent identical rows are offset from the slits in the second row in the transverse direction.
  • multi-slit pattern can include double slit patterns, triple slit patterns, and quadruple slit patterns, for example.
  • FIG. 16A illustrates a pattern featuring a single slit pattern that comprises sinusoidal skip slits. For example, each midpoint of a slit is roughly aligned with the space between two adjacent slits in different columns. When opened in FIG. 16B, this pattern advantageously resulted in a high flatness when strained up to a flattenability strain threshold for the slitted abrasive sheet.
  • a wavy pattern, as used herein can be a two-dimensional slit pattern having a series of alternating ridges and valleys which may be regular or irregular.
  • a sinusoidal pattern can be type of wavy pattern that is smooth and periodic having troughs and peaks that alternate above and below a baseline.
  • at least a portion of the slits can be “compound slits,” which are slits having more than two terminal ends.
  • a straight, imaginary line extends between and connects these terminal ends.
  • the straight, imaginary line extending between and connecting the terminal ends of a first slit is substantially colinear with the straight, imaginary line extending between and connecting the terminal ends of a directly adjacent slit.
  • all of the straight, imaginary lines extending between and connecting the slit terminal ends in a single row are approximately colinear.
  • the reticulated abrasive articles 100 are expandable in more than one direction.
  • the reticulated abrasive articles 100 have a longitudinal direction and a width direction, and have a plurality of regions 116 of an abrasive material 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 reticulated abrasive article 100 is expandable in at least two directions.
  • the presently disclosed article 100 also includes a multitude 124 of the plurality of regions 116 extending radially from a common intersection 125.
  • the presently disclosed articles 100 provide a first abrasive brightness when separated into a first width dimension between the plurality of regions 116 of abrasive material 20 and a second reflective brightness when separated into a second width dimension between the plurality of regions 116 of reflective material 20.
  • the slits 11, 21, 31, perforations, or combinations thereoef can be made using any known techniques, such as rotary die cutting, laser cutting, ultrasonic slitting, and the like.
  • FIG. 21 and 23 illustrate an alternative slit configuration referred to as a biaxial multi-slit pattern. While the plurality of slits in previously described multi-slit patterns, such as the double slit pattern of FIG.
  • the abrasive sheet 100 has a slit pattern in which half of the slits 121 are oriented along a machine direction and the remaining half of the slits 111 are oriented along the transverse or cross direction.
  • the slits 121 and 111 otherwise collectively provide a multi-slit pattern as previously described.
  • the tension axes exactly correspond to the machine and cross directions.
  • the application of tension along the tension axes can occur simultaneously or sequentially.
  • tensioning along a single axis is sufficient to expand the abrasive sheet, especially if that axis is at an angle to both the slits 121 and 111, e.g., at a 45-degree angle to both of them.
  • the biaxial multi- slit pattern is auxetic—that is, when stretched along one axis, it will expand along an orthogonal axis. Deployment can also be achieved by applying tension along any axis including a combination of those two vectors—for example, tension applied along a 45-degree angle can be effective.
  • at least a portion of the slits can be “compound slits,” which are slits having more than two terminal ends. In the current example, a straight, imaginary line extends between and connects these terminal ends.
  • the straight, imaginary line extending between and connecting the terminal ends of a first slit is substantially colinear with the straight, imaginary line extending between and connecting the terminal ends of a directly adjacent slit.
  • all of the straight, imaginary lines extending between and connecting the slit terminal ends in a single row are approximately colinear. However, a region of each of the slits between the terminal ends are not colinear with the imaginary straight line connecting the slit terminal ends in each row.
  • FIG. 24A depicts an abrasive sheet 100 having a hexaxial multi-slit pattern in which slits 131, 121, and 111 are aligned along six different directions along the plane of the abrasive sheet 100, each direction forming an angle of 60o relative to each of the other two directions.
  • Each pattern of slits 111, 121, 131 are aligned along a given direction which can intersect with each other at their terminal ends to form a repeating pattern of compound slits each comprised of a pair of slits oriented at an angle of 60o relative to each other.
  • FIG. 24B shows the abrasive sheet 100 partially deployed through the application of tension, where tension components are aligned along six tension axes shown.
  • Abrasive article refers to an abrasive good that is expanded and configured to be laminated onto an attachment layer or is bonded to an attachment layer. In one embodiment, the abrasive article can refer to an intermediate and can exist on a roll (prior to converting/cutting into the finished good).
  • Abrasive sheet refers to an intermediate abrasive product that is not yet slitted, expanded, or attached to an attachment layer.
  • Abrasive sheet plane refers to a plane of the abrasive sheet established by the maximum median height of the edges across the entire abrasive sheet (when not in a strained configuration).
  • Air permeable refers to a material or structure that allows for the passage of air or gas through its surface or volume.
  • the air permeability of a material can be quantified with various methods, including the Gurley method.
  • Continuous impermeable substrate refers to an unbroken layer of material (before slitting) that is not air permeable which can include coated paper and polymeric films, but generally excludes uncoated non-wovens and paper.
  • the continuous impermeable substrate can generally have less than 1% void space or have an air permeability rating of less than 2 cfm/sqft according to ASTM D737-18 (2023).
  • Cut-out refers to a surface area of the sheet that is removed from the sheet when a slit intersects itself. It is understood, however, that many forming techniques result in the removal of some surface area of the sheet that is not considered a “cut-out” for the purposes of the present application.
  • “Different positions” means that the center positions in the connecting parts in the second direction needs to differ each other, and can partially overlap as long as at least some of the connecting parts differ from each other.
  • “Elastomeric” refers to any material that is able to resume its original shape when deforming forces are removed.
  • “Fixed opened area” refers to an open area of the opening after a fixing process has been performed and the mesh abrasive sheet is not under strain nor subjected to a tensile force.
  • “Fixing” refers to a process where an article is transformed into a more dimensionally stable article or form.
  • fixing can refer to heating and/or applying pressure to a stressed slitted abrasive sheet such that the openings do not return to their shape in the absence of fixing and applied stress.
  • fixing can refer to a process distinct from lamination.
  • “Flat” refers to a characteristic of having a smooth and uniform surface without any bumps, waves, wrinkles or other irregularities that may affect the sheet's accuracy or performance.
  • flat is established by the plane of the functional layer having uniform thickness without the abrasive particles themselves.
  • flat can be based on a ratio of height difference/average thickness of less than 2, or less than 1.5, or less than 1.1 as determined with the topological profile method.
  • “Flat Compressed” refers to compression in the orthogonal direction to a plane of a sheet, such that, as the slitted abrasive sheet is opened under tension, no portion of the strand overlaps any other abrasive portion of the sheet when this compression occurs.
  • condition refers to a maximum applied strain along the primary tension axis where a condition occurs.
  • condition can be where the slitted abrasive sheet can be Flat Compressed orthogonal to the original, untensioned plane of the sheet onto a substrate while maintaining the overall nominal strain of the sheet.
  • the condition is where the strain results in no foldovers in a laminated mesh abrasive article even if there were twists in the strands of the opened abrasive sheet when subjected to the maximum applied strain.
  • “Foldover” refers to a region of the abrasive backing that has been inadvertently folded over during the tensioning process and set after the abrasive sheet has been laminated onto the attachment layer. The foldover results in exposure of the non-abrasive backside on the top of the functional abrasive surface. For example, a foldover can be caused by a twist that does not flatten after lamination or a heat/pressure process.
  • “Mesh abrasive article” refers to a continuous sheet of coated abrasive having holes formed therein to allow extracted dust to pass through and capable of attachment to a planar surface of a motorized sanding tool.
  • Opening refers to an open area created by subjecting a slit to a tensile force. An opening can have a stressed opened area, unstressed opened area, and/or a fixed opened area depending on whether the opened abrasive sheet is unstressed or stressed.
  • Reticulated refers to a net like formation of strands or regions that are joined at certain points.
  • the present disclosure provides a reticulated abrasive article having a longitudinal direction and a width direction, and including a plurality of strands of an abrasive material attached to one another at bridging regions in the abrasive material and separable from one another between the bridging regions to provide openings in the abrasive material, where the openings provide a variably expandable area, and where the abrasive material comprises a functional major surface and a less functional major surface, also where each of the openings has a longitudinal dimension, a width dimension, and each of the plurality of strands has a thickness, and also where the reticulated abrasive article is expandable in at least one direction.
  • expansion of the reticulated abrasive article is considered as a change in the area of the openings in the reticulated abrasive article.
  • Presently disclosed reticulated abrasive articles can provide varying amounts of open area when expanded in one or more directions.
  • As the reticulated abrasive articles are expanded the amount of open area is increased, resulting in lower brightnesses and increased permeabilities.
  • expansion can be conducted before the reticulated abrasive article is mounted on a substrate.
  • expansion occurs due to motion of a user, such as for example, when the reticulated reflective article is mounted on an elbow or knee region of active wear.
  • Single slit pattern refers to slits that form individual rows each extending across the sheet transversely, where the rows form a repeating pattern of individual rows along the axial length of the sheet, and the pattern of slits in each row is different than the pattern of slits in the directly adjacent rows.
  • the slits in one row may be axially offset or out of phase with the slits in the directly adjacent rows.
  • Each of the slits in the plurality of slits can, in some embodiments, include multiple peaks and valleys within the plane of the sheet.
  • “Skip slit” refers to a pattern of a plurality of slits where a midpoint of any of a column of slits is not aligned (along a perpendicular axis to the column of slits) with a midpoint of any of an adjacent column of slits.
  • “Slit” refers to a long narrow cut or opening. As used herein, a “slit” is defined as a narrow cut through the article forming at least one line, which may be straight or curved, having at least two terminal ends. In one embodiment, perforations are a specific type of slit that are created by making a series of small, regularly spaced slits along a line.
  • slits are designed to weaken the material along the perforation line, allowing it to be easily torn or separated along that line.
  • a slit is generally not a cut-out.
  • many cutting technologies produce a “kerf,” or a cut having some physical width.
  • a laser cutter will ablate some surface area of the sheet to create the slit
  • a router will cut away some surface area of the material to create the slit
  • crush cutting creates some deformation on the edges of the material that forms a physical gap across the surface area of the material.
  • molding techniques require material between opposing faces of the slit, creating a gap or kerf at the slit.
  • the gap or kerf of the slit will be less than or equal to the thickness of the material.
  • a slit pattern cut into a metal foil that is 0.18 millimeters thick might have slits with a gap that is approximately 0.18 millimeters or less.
  • the width of the slit could be increased to a factor that is many times larger than the thickness of the material and be consistent with the technology disclosed herein.
  • strain refers to deformation of a solid due to stress and can be measured as a change in length divided by the original length of the material.
  • “Stressed opened area” refers to an open area of the opening while the opened abrasive sheet is under strain or subjected to a tensile force.
  • “Stressed state” refers to a property of the abrasive sheet when it is subjected to tensile force along at least one axis up to the flattenability strain threshold.
  • “Topographical Profile Method” refers to a method where the plane of the base material is compared to the raised portions of the base material and similar to the method described in WO2023037272.
  • “Twist” refers to a strand of the opened abrasive sheet that twists or bends out of plane of the opened abrasive sheet, forming a bent or raised shape, or partial helix shape.
  • "Unstressed opened area” refers to open area of an opening of an opened abrasive sheet that is unfixed and/or unstrained.
  • "Unstressed state” refers to a state of the abrasive sheet when no tensile force acts upon it.
  • Topological Profile Method [0221] The topological profile was determined using a Keyence VKX1100 confocal 3D measuring confocal microscope (Keyence Corporation, Osaka, Japan). A 4-inch by 4-inch swath of the combination was placed on the sample tray and at 2.5x magnification, with ring and axial lighting was used for the evaluation. Four images in a 2” x 2” square were taken at 2.5x magnification and stitched together to form a single image for analysis. The resulting image was analyzed using VK Series Analyzer Software (Keyence Corporation, Osaka, Japan).
  • Abrasion Test Method A 3” diameter disc was cut out of each heat-laminated, flexible abrasive sample. The 3” disc was attached to a Festool LEX 377/2,5 sander which was connected to a Festool CT 36 E dust extraction system. The sander was provided with compressed air such that the dynamic air pressure was at 50 psi pressure while the sander was operating with the throttle valve fully open.
  • Each abrasive disc was tested on an unsanded section of an 18” tall x 24” wide automotive test panel, available from ACT Test Laboratories, LLC., Hillsdale, Mich., by manually moving the running sander in a linear motion in a single 18” tall lane on the test panel for 30 seconds, using approximately 4 kg of downforce. The weight of the test panel was taken before and after the test, the difference was recorded as the cut value.
  • Surface Finish Measurements [0226] After sanding, the finish (Ra, Rz, Rz max) of each sanded lane was measured in 5 locations using a S100 Series profilometer equipped with a PK-03 diamond stylus, available from Taylor-Hobson, Sheffield, UK.
  • Air permeability Measurements Air permeability measurements of the abrasive article were determined in accordance with ASTM D737-18 (2023) using a Gurley 4301 permeometer. The results of the air permeability testing are reported in cubic feet per minute per square foot (cfm/ft2)." A sample may be considered “air permeable” when the [0230] Foldover Determination Method [0231] Foldovers occur when a laser-slit sample is stretched beyond the point at which it can be heat laminated in a flattened state.
  • the foldovers can occur primarily to the strands but can also happen to the bridging regions. In this case, the twists of the stretched, laser-slit sample foldover during lamination, such that the non-abrasive backside of the abrasive backing is exposed on top of the abrasive surface.
  • the number of foldovers was counted for each sample by viewing each 3” disc sample through a 2.75 magnification lens and manually counting the foldovers on each sample.
  • Percent Strain Determination The percent strain was determined by taking a rectangular sample 78 mm in length by 152 mm wide and stretching the rectangular sample in the machine direction of the pattern and measuring the final length with a ruler. Percent strain is the difference between the final length and the original length of 78 mm divided by the original length of 78 mm.
  • Sample Preparation Objects and advantages of this disclosure are further illustrated by the following non- limiting examples. Particular materials and amounts thereof recited in these examples, however, as well as other conditions and details, should not be construed to unduly limit this disclosure.
  • ACR Trimethylolpropane triacrylate.
  • AMOX Di-t-amyl oxalate.
  • BKG1 Backing 1; 120 g/m 2 weight net mesh available from Sitip Technical Textiles, Cene, Italy.
  • CHDM 1,4-cyclohexanedimethanol.
  • 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.
  • EP2 Abisphenol-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, Inc., Columbus, Ohio.
  • EP3 (3',4'-epoxycyclohexylmethyl) 3',4'-epoxycyclohexanecarboxylate.
  • ESTANE A thermoplastic polyether-based polyurethane resin, obtained under the trade designation "ESTANE 58887 NAT 021" from Lubrizol Advanced Materials, Cleveland, Ohio.
  • FLL An inorganic micronized functional filler, obtained under the trade designation "MINEX 3" from Unimin Corp, New Canaan, Conn.
  • P600 A grade P600 aluminum oxide abrasive mineral, obtained under the trade designation "ALODUR BFRPL” from Treibacher Industrie AG.
  • PC1 Mixture of 4-thiophenylphenyl diphenyl sulfonium hexafluoroantimonate, and bis[4- (diphenylsulfonio)phenyl]sulfide bis(hexafluoroantimonate) in propylene carbonate, obtained under the trade designation CPI 6976 from Aceto Corporation, Port Washington, N.Y
  • PC2 2,2-dimethoxy-2-phenylacetophenone, obtained under trade designation IRGACURE 651 from BASF, Wyandotte, Mich.
  • PC3 ⁇ 6 -[xylene(mixed-isomers)] ⁇ 5 -cyclopentadienyliron (1+) hexafluoro antimonate(1-).
  • PC4 Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate, obtained under the trade designation IRGACURE TPO-L from BASF, Wyandotte, Mich.
  • PEP A high molecular weight, hydroxyl-terminated, saturated, linear, semi-crystalline, copolyester, with a weight average molecular weight of 35,000 g/mol, available as "DYNAPOL 5 1227" from Evonik Industries, Parsippany, N.J.
  • PET A 1.97 mil (50 ⁇ m) thick polyester terephthalate film, obtained under the trade designation 602197 PET FILM from 3M Company.
  • PI 2-hydroxy-2-methyl-1-phenyl-1-propanone.
  • Prop Carb Propylene carbonate, obtained under the trade designation JEFFSOL PC from Huntsman Corp, Woodlands, Tex.
  • ZNST A 39-41 percent by weight aqueous zinc stearate soap dispersion obtained under trade designation EC994C from eChem LTD, Leeds, UK.
  • Preparation of the make resin [0246] A series of make resins were prepared as follows, according to the compositions listed in Table 1.
  • AMOX, EP1, EP2, CHDM and PEP were directly metered to a twin-screw extruder running at 300 rpm with temperature zones of 30, 105, 110, 100, 65, and 60 °C. This mixed resin was then fed to a pin mixer running at 1750 rpm, and ACR, PC2, PC3, PC4, and PropCarb were directly metered into the pin mixer. The output from the pin mixer was fed to a heated coating die, where the flow rate from the pin mixer was controlled so as to achieve the make resin target on the abrasive backing.
  • Size Resin [0247] [0248] Preparation of Size Resin [0249] Table 2 below lists the components and the amounts used to formulate the Size Resins 1 and 2. Each size resin was prepared by combining and mixing EP2, EP3 and ACR, and optionally FLL, in a container. Prior to abrasive making, PC1 and PI were added to the premixed resin batch and stirred for 30 minutes at room temperature until homogeneous. [0250] [0251] Method of making the abrasive sheet [0252] ESTANE resin was extrusion cast as a first thermoplastic polyurethane film, at an average thickness of 5 mils (127 ⁇ m), onto the 1.97 mil (50.04 ⁇ m) PET by means of single-screw extruder.
  • Make Resin was coated onto the ESTANE film at a nominal coating weight of 16.5 g/m2 and the film assembly passed under a Fusion UV Systems with one set of D-bulbs and one set of V-bulbs, both operating at 600 W/in (236 W/cm).
  • Abrasive mineral P600 was then coated onto the make resin at a nominal coating weight of 28 g/m2 and the web was then heated under infrared heaters, at a nominal web temperature setting of 100° C., for about 7 seconds.
  • the Size Resin was then roll coated onto the make layer and abrasive particles at a nominal dry coating weight of 13 g/m2 and passed under a Fusion UV Systems with one set of H-bulbs, and two sets of D-bulbs, all three operating at 600 W/in (236 W/cm). It was then processed through infrared ovens having a target exit web temperature of 125° C. ZNST at a nominal coating weight of 9 g/m2 was then coated onto the size layer and processed through a drying oven with a target exit web temperature of 135° C.
  • the abrasive web was then flexed by wrapping it around a first 1 ⁇ 4 inch (6.35 mm) diameter round metal bar with the backside of the abrasive in contact with the metal bar.
  • the bar was oriented at a 45° angle relative to the web direction.
  • the web was wrapped around the 1 ⁇ 4 inch (6.35 mm) diameter bar such that approximately one half of the bar was in contact with the backside of the web. This resulted in a configuration in which the web movement prior to the bar was opposite the direction of web movement after the bar.
  • the abrasive web was wrapped around a second 1/4 inch (6.35 mm) diameter round metal bar with the backside of the abrasive in contact with the metal bar.
  • This second bar was also at a 45° angle relative to the web direction, and a 90° orientation from the first bar.
  • the wrap angle for the first and second bars was the same, and in both cases the backside of the abrasive was in contact with the bar.
  • the resultant coated abrasive web was then maintained at room temperature (i.e., 20-24° C.) until used in subsequent examples.
  • Method of laminating to a net mesh [0256] The PET liner was removed from the abrasive and heat-laminated to BKG1 using a SteamFast Model SF-680 iron, available from Vornado Air LLC, Andover, Kansas. The iron was set to the “linen” setting and allowed to heat up to steady state.
  • a 12” by 12” square of BKG1 was cut out and placed onto a rigid cardboard substrate with the loop side in contact with cardboard.
  • a 7” by 7” square of the abrasive was placed on top of the BKG1, abrasive facing up, and the abrasive and BKG1 were pinned to the rigid cardboard substrate.
  • the 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 was held in that position for 1 minute and 30 seconds. After this time, the multilayer sample was removed from the iron and cooled to room temperature for 1 minute.
  • Comparative Example C1 was prepared by cutting a 3” diameter disc out of each heat- laminated, flexible abrasive sample before any slitting occurred as described below.
  • Making slitted abrasive sheets [0259] The PET liner laminate was removed from the abrasive, and the abrasive was laser-slit according to a pattern using an Epilogue Fusion laser model 13000 operating at 75 watts, 100% speed, 70% power, 50% frequency conditions. A 12” by 12” square of BKG1 was cut out and placed onto a rigid cardboard substrate with the loop side in contact with cardboard.
  • Comparative Example C3 was not strained (thus under zero tension). Each of the strained samples were flat compressed against a flat substrate while maintaining the overall nominal strain and foldover was assessed in any part of the sheet. Comparative example C2 represents the amount of strain where the initial foldover was observed. [0262] Foldovers were counted, % abrasive area calculated and air permeometer measurements made per the test methods described above. Table 3 summarizes the samples made, Percent Strain, Percent Abrasive Area, Height differential/thickness via the Topographical Profile Method, Open Area, Number of Foldovers.
  • Comparative Example C2 was stretched to above one foldover for the 3 inch diameter sample which indicates that the flattenability strain threshold was reached.
  • Table 3 - Dimensions of varying degrees of tension Height % open % abrasive # of Example % Strain differential/Thickness area area foldovers C1 0 N/A 0 100 0 C2 143.6 2.09 52.8 47.2 60 EX1 53.8 0.84 39.6 60.4 0 EX2 39.7 1.02 34.0 66.0 0 C3 0 0.57 7.5 92.4 0
  • Surface finish of samples [0266] Abrasion tests and surface finish measurements were taken for the samples and the results summarized in Table 4.
  • Comparative example C4 is commercially available as Abranet Ace P600, from Mirka Ltd. (Finland). [0267] Table 4 - Abrasion tests and surface finish measurements Air avg Ra avg Rz avg rmax Visual total cut Example Permeability ( ⁇ m) ( ⁇ m) ( ⁇ m) Finish (g) C1 1.2* 0.88 5.63 6.46 Acceptable 0.69 C2 >377 1.01 6.18 7.72 Acceptable 0.11 EX1 >377 0.79 5.22 6.24 Acceptable 0.37 EX2 >377 0.86 5.52 7.04 Acceptable 0.62 C3 128 0.86 5.48 6.86 Acceptable 0.67 C4 >377 0.35 2.38 3.04 Acceptable 0.38 *A small amount of air leaked through the space between the loop fabric and the clamps leading to a non-zero measurement.
  • EX1, EX2 have air permeability of the mesh abrasive article of greater than 377 cubic feet/min-square feet) when measured according to the air permeability measurement method described herein and an acceptable visual finish as well as a lower total cut.
  • P1200 grit example A commercially available disc of 3M Purple Finishing Film, P1200, part number 30668 was hand laminated at room temperature onto a 12 inch by 12 inch square of 3M Adhesive Transfer Tape 9453LE adhesive with the abrasive side of the disc facing away from the adhesive, on the opposite side of the adhesive was the paper release liner.
  • the abrasive/adhesive/paper liner was laser-slit according to the pattern shown in FIG. 16A using an Epilogue Fusion laser model 13000 operating at 75 watts, 50% speed, 100% power, 50% frequency conditions.
  • a 12 inch by 12 inch square of BKG1 was cut out and placed onto a rigid cardboard substrate with the loop side in contact with cardboard.
  • the paper liner was removed from the abrasive/adhesive/paper liner sample and one end was pinned to the BKG1 on the rigid cardboard substrate, the other side was expanded to 34% strain as illustrated in FIG. 16B and pinned to the BKG1 on the rigid cardboard substrate while in the stretched position with the abrasive facing away, from the BKG1.
  • the BKG1 and abrasive layer were now laminated together and were removed from the rigid cardboard substrate and cut into a 3inch disc.
  • the P1200 grit example is shown on FIG. 25 as having a a sinusoidal pattern).
  • the final product used P1200 grit which is significantly finer than the P1000 grit number mesh products that are currently commercially available. Using the method described herein, it is possible to achieve a more refined abrasive surface in a coated abrasive product when compared to current state-of-the-art methods.
  • grits with a significantly finer particle size than P1000 grit while maintaining the dust extraction properties of a mesh abrasive article, thereby providing a smoother finish with finer scratching that improves the overall quality of the abrasive product.
  • Other potential abrasive particle sizes used can be those finer than or equal to P1200, P1500, P2000, or P2500 grit size.

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Abstract

Des aspects de la présente invention concernent un procédé de fabrication d'un article abrasif à mailles qui consiste à fournir une feuille abrasive ayant une couche de base de substrat imperméable continue et à fendre la feuille selon un motif pour créer une feuille abrasive fendue. La feuille abrasive fendue est ensuite tendue jusqu'à ce qu'elle atteigne une contrainte allant jusqu'à un seuil de contrainte d'aplatissement, amenant les fentes à s'ouvrir dans des zones contraintes et à former une pluralité d'ouvertures, formant ainsi une feuille abrasive ouverte.
EP24710231.2A 2023-01-30 2024-01-30 Article abrasif maillé à motifs fendus et son procédé de fabrication Pending EP4658450A1 (fr)

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PCT/US2024/013467 WO2024163414A1 (fr) 2023-01-30 2024-01-30 Article abrasif maillé à motifs fendus et son procédé de fabrication

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Publication number Priority date Publication date Assignee Title
US2871218A (en) 1955-12-01 1959-01-27 Goodrich Co B F Simulated vulcanizates of polyurethane elastomers
NO134790C (no) 1968-07-09 1984-03-22 Smith & Nephew Klebende,; trykkfoelsomt, vanndamp-permeabelt produkt for bruk paa hud hos mennesker.
ES477698A1 (es) * 1978-02-17 1979-12-01 Minnesota Mining & Mfg Un metodo de fabricar un producto abrasivo de baja densidad,esponjoso, no tejido.
AU560088B2 (en) 1982-04-08 1987-03-26 Smith & Nephew Associated Companies Plc Surgical adhesive dressing
USRE33353E (en) 1985-01-24 1990-09-25 Minnesota Mining And Manufacturing Company Thin film surgical dressing with delivery system
US5088483A (en) 1988-11-04 1992-02-18 Minnesota Mining And Manufacturing Co. Adhesive frame bandage
US6884504B2 (en) 2001-05-04 2005-04-26 3M Innovative Properties Company Repositionable adhesive label for optical recording media
US6838589B2 (en) 2003-02-19 2005-01-04 3M Innovative Properties Company Conformable wound dressing
CN101115584B (zh) * 2004-12-30 2012-04-04 3M创新有限公司 磨料制品及其制造方法
US7285146B2 (en) * 2005-12-28 2007-10-23 3M Innovative Properties Company Resilient abrasive article
CA3074408A1 (fr) 2017-09-01 2019-03-07 3M Innovative Properties Company Materiau reflechissant reticule
WO2023037272A1 (fr) 2021-09-08 2023-03-16 3M Innovative Properties Company Article abrasif à combinaison calandrée

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