Abstract:
A masking article includes a bendable backing layer having first and second opposed major surfaces, an adhesive arranged on at least a portion of at least one of the first and second major surfaces, wherein the adhesive has a thickness, and a raised element arranged on the same major surface as the adhesive, wherein the raised element extends beyond the thickness of the adhesive such that the masking article can be moved along an application surface to a desired location without having the adhesive adhere to the application surface, and such that the masking article can be secured to the application surface by pressing the backing layer in the region opposite the adhesive, thereby forcing the adhesive into contact with the application surface to secure the masking article to the application surface at the desired location.

Description:
BACKGROUND 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61,161,242, filed Mar. 18, 2009, the disclosure of which is incorporated by reference herein in its entirety. 
         [0002]    The present invention relates generally to paint masking and, more particularly, to a sheet-like adhesive article that can be selectively secured to a mounting surface by a pressure sensitive adhesive. More particularly, the present invention relates to an adhesive article, such as a paint masking sheet assembly, that can be manually slid across a mounting surface and, once properly positioned, easily secured in place by manually pressing the article against the mounting surface. 
         [0003]    When painting or staining a surface, care must be taken so that the paint does not get on the surfaces adjacent the area to be painted. This can be accomplished by carefully painting the surface, or by masking off the area around the area to be painted. To facilitate the masking process, masking tape articles having specific sizes and shapes tailored to specific masking applications have been developed. 
         [0004]    Paint masking articles are known in the prior art. U.S. Pat. No. 6,579,587 (Schnoebelen, Jr.), for example, discloses a paint mask for masking corners. The paint mask if formed of a thin, flexible sheet having opposite faces. The paint mask includes a first leg and a second leg that are generally rectangular in shape, and the legs intersect to form a right angle adapted for masking a corner adjacent an area. U.S. Pat. No. 6,852,408 (Hansen et. al.) discloses a masking device including a substantially rigid body, the body having an underside and adjoining first and second edges and an adhesive portion positioned on the underside adjacent to one or more of the first and second edges. 
         [0005]    The need exists for an inexpensive masking article that is lightweight, easy to make, and easy to use. In particular, the need exists for a masking article that can be accurately positioned at a selected location prior to securing it to the surface to be masked. 
       SUMMARY 
       [0006]    Windows are often masked to keep the window glass from being splattered with paint, and to create sharp clear paint lines. Conventional techniques, such as taping, tend to be very time consuming, taking as much as half the time for the total painting project. The present invention addresses this problem in that it provides a faster, easier, and more accurate technique for masking windows for painting, especially small windows. 
         [0007]    In one embodiment, the present invention provides a masking article including a bendable backing layer having first and second opposed major surfaces, an adhesive having a defined thickness arranged on at least a portion of at least one of the first and second major surfaces, and a raised element arranged on the same major surface as the adhesive, wherein the raised element extends beyond the thickness of the adhesive such that the masking article can be moved along an application surface to a desired location without having the adhesive adhere to the application surface, and further such that the masking article can be secured to the application surface by pressing the backing layer in the region opposite the adhesive, thereby forcing the adhesive into contact with the application surface to secure the masking article to the application surface at the desired location. 
         [0008]    In another aspect, the present invention provides a masking sheet having a base substrate layer having a front side and an opposite back side. The front side of the substrate allows paint to adhere to it. A securing mechanism is arranged on the back side of the substrate layer. The securing mechanism includes a raised element and a pressure sensitive adhesive. The adhesive may be disposed between the raised element and the backside of the substrate layer. The pressure sensitive adhesive has an exposed surface along at least a portion of the perimeter edge of the back side of the substrate. The height of the adhesive, as measured from its exposed surface to the front side of the substrate is shorter than the height of the raised element, as measured from its application surface to the front side of the substrate. The thickness of the raised element, stiffness of the substrate material, and exposed surface area prevents the adhesive from contacting and/or adhering to a surface abutting the back side of the substrate layer in the absence of the application of pressure against the outer edges of the front side of the substrate layer. 
         [0009]    When the masking sheet has its back side surface abutting another surface, such as another masking sheet, it will not adhere thereto because the pressure sensitive adhesive thereon is spaced from that surface. The unattached sheets can then be stacked like a deck of playing cards for easy transportation and use. When pressure is applied to the front side of the substrate opposite the pressure sensitive adhesive thereon, the sheet bearing the adhesive is sufficiently flexible and deformable so that at least a portion of the exposed adhesive is brought into contact with an adjacent surface. In this manner, a plurality of sheets may be formed into a pad. The plurality of sheets may also be attached together to form a pad or roll using various means. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective top view of a stack masking articles according to the invention. 
           [0011]      FIGS. 2A  is a perspective bottom view of a stack of masking articles according to the invention. 
           [0012]      FIG. 2B  is an exploded perspective bottom view of a stack of masking articles. 
           [0013]      FIG. 3  is a bottom plan view of a single sheet in the stack of  FIG. 2B . 
           [0014]      FIG. 4  is a sectional view taken along line  4 - 4  of  FIG. 3 . 
           [0015]      FIG. 5  is a sectional view of a plurality of unattached sheets in a stack of the present invention. 
           [0016]      FIG. 6  is a sectional view of another embodiment of the invention showing a release layer. 
           [0017]      FIG. 7A  is a top perspective view of  FIG. 6 . 
           [0018]      FIG. 7B  is a perspective view of a variation on the embodiment of  FIG. 6 . 
           [0019]      FIG. 8A  is a bottom perspective view of  FIG. 6  as viewed from the opposite side of either  FIG. 7A  or  7 B. 
           [0020]      FIG. 8B  is a bottom perspective view of a variation of the embodiment of  FIG. 6 . 
           [0021]      FIG. 9  is a sectional view of a pad of sheets. 
           [0022]      FIGS. 10A-D  are bottom plan views of  FIG. 3 , showing raised elements having various designs. 
           [0023]      FIG. 11  is a perspective top view of another embodiment of the invention showing a pad of attached sheets. 
           [0024]      FIG. 12  is a bottom plan view of a single sheet in the pad of  FIG. 11 . 
           [0025]      FIG. 13  is a perspective view of another embodiment of the invention showing unattached sheets on a release liner. 
           [0026]      FIGS. 14A and 14B  are perspective views of another embodiment of the invention showing sheets in roll form in which individual sheets are separated at perforation lines ( FIG. 14A ), or dispensed using a cutting blade ( FIG. 14B ). 
           [0027]      FIGS. 15A and 15B  are sectional side views showing the adhesive article being applied to a window pane. 
           [0028]      FIG. 16  is a diagrammatic plan view showing a single sheet being slid across a window pane, and into the corner of the window. 
           [0029]      FIG. 17  is a perspective plan view of the invention showing four masking sheets covering glass in a window frame. 
           [0030]      FIG. 18  is a plan view of another embodiment of the invention. 
           [0031]      FIGS. 19A-19C  are perspective views of another embodiment of the invention showing the release liner acting as the raised element. 
           [0032]      FIG. 20A  is a sectional view taken along line  20 A- 20 A of  FIG. 19B . 
           [0033]      FIG. 20B  is a sectional view taken along line  20 B- 20 B of  FIG. 19C . 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIG. 1  is a perspective top view of a stack  100  of masking articles or sheets  105  according to one embodiment of the invention. The stack  100  includes a plurality of individual sheets  105 , which may be loosely arranged (i.e. not connected, affixed, or attached to each other) to form a stack similar to a deck of playing cards, or the individual sheets may be connected or affixed to form a pad of sheets. As explained in greater detail below, each sheet  105  includes a substrate  125 , and a securing mechanism. 
         [0035]      FIG. 2A  is a perspective bottom view of the stack  100 . That is,  FIG. 2A  is similar to  FIG. 1  except the stack  100  has been flipped over to show the securing mechanism, which includes a raised element  120  and a pressure sensitive adhesive  115 . 
         [0036]      FIG. 2B  is similar to  FIG. 2A , and shows the stack  100  with the plurality of sheets  105  not attached to each other. That is, the individual sheets  105  can be readily moved relative to each other. A stack  100  of individual sheets  105  is a convenient way of transporting and handling. 
         [0037]      FIG. 3  is a bottom plan view of an individual sheet  105 . In the illustrated embodiment, the bottom surface of the sheet  105  includes a pressure sensitive adhesive  115  arranged along the entire perimeter edge of the substrate  125  ( FIG. 4 ), and a raised element  120  arranged on a central region of the sheet  105 . It will be recognized that the configuration of the pressure sensitive adhesive  115  and the raised element  120  is not critical, so long as it allows the masking article  105  to be slid across a surface to a desired location by a user, and then affixed at the selected position by pressing the masking article against the surface. For example, the pressure sensitive adhesive  115  may be arranged along only selected portions of the perimeter edge region of the substrate  125 , or the raised element  120  may be provided along the perimeter edge region of the substrate  125 , and the pressure sensitive adhesive  115  may be provided on a selected interior (or regions) of the substrate. 
         [0038]    In the illustrated embodiment, the pressure sensitive adhesive  115  is disposed between raised element  120  and base substrate  125  ( FIG. 4 ). That is, the pressure sensitive adhesive  115  is a continuous coating on the back side of substrate  125 . The raised element  120  is arranged directly on top of pressure sensitive adhesive  115  except for along edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4 . The raised element  120  may be a coating layer coated over the pressure sensitive adhesive  115  that serves to detackify the pressure sensitive adhesive  115 , or the raised element  120  may be, for example, a film layer arranged over the pressure sensitive adhesive  115 . 
         [0039]    In various embodiments, the exposed adhesive regions, such as edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4 , may have a width of at least about 1 millimeters (mm), at least about 2 mm, at least about 3 mm, or at least about 4 mm, and a width of no greater than about 16 mm, no greater than about 14 mm, no greater than about 12 mm, and no greater than about 10 mm. It has been found that, depending on the type of adhesive  115  used and depending on the height of the raised element  120 , adhesive regions having widths less than about 3 mm may have difficulty staying adhered to an application surface. In addition, it has been found that adhesive regions having widths greater than about 13 mm may have difficulty sliding across the application surface. In one specific embodiment, the adhesive regions are perimeter edge regions, and the adhesive edges have a width of from about 4 mm to about 9 mm. 
         [0040]      FIG. 4  is a cross-sectional view of the sheet  105  of  FIG. 3 . The sheet  105  includes a base layer or substrate  125 , and a securing mechanism including a pressure sensitive adhesive  115  and a raised element  120 . The sheet  105  has a top side  130  and a bottom side  135 . The top side  130  may also be referred to as the paint adhering side. The bottom side  135  may also be referred to as the application side. Exposed adhesive edges  1 - 1  and  2 - 2  are also shown in  FIG. 4 . 
         [0041]      FIG. 5  shows a cross-sectional view of a plurality of sheets  105   a - d  stacked, but not attached. Raised elements  120   a - d  serve to (i) overlay and detackify the pressure sensitive adhesive  115   a - d  except for edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4  as seen in  FIG. 3 , and (ii) provide a thickness  140   a - d  to prevent the pressure sensitive adhesive  115   a - d  from contacting a surface abutting the back side of the substrate layers in the absence of a force sufficient to otherwise cause the pressure sensitive adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4  to contact the back side of the adjacent substrate layer. 
         [0042]    In certain embodiments, the raised element  120  may have a thickness of at least about 0.005 mm, at least about 0.01 mm, or at least about 0.02 mm, and a thickness of no greater than about 0.4 mm, no greater than about 0.35 mm, or no greater than about 0.3 mm. In this manner, the raised element  120  allows the individual unattached sheets  105  to be easily slide over each other, similar to a deck of playing cards. Raised element  120  also allows sheet  105  to slide across an application surface without adhering to the application surface (in the absence of the application of pressure against the adhesive outer edges of the front side of the substrate layer sufficient to cause the adhesive outer edges to contact the application surface). Although  FIG. 5  shows a single raised element, in some embodiments, two or more raised elements may be provided, as shown and further described, for example, in  FIGS. 10A-D . 
         [0043]      FIG. 6  is a sectional view of another embodiment of the present invention. Sheet assembly  205  has a base substrate  125 , a release coating layer  145 , and a securing mechanism including a pressure sensitive adhesive  115  and a raised element  120 .  FIG. 6  is similar to  FIG. 4  except release layer  145  is coated on the front side of substrate  125 . Release layer  145  allows pressure sensitive adhesive  115  to be easily removed from the front side of substrate  125  if stacked and pressure is applied against the outer edges of the front side of substrate  125 . 
         [0044]      FIG. 7A  is the top perspective view of  FIG. 6 . As illustrated, the release coating  145  is coated over the entire front side of substrate  125 . The release coating  145  allows exposed adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4  (as shown in  FIG. 3  and partially shown in  FIG. 7A ) of pressure sensitive adhesive  115  to be easily removed from the front side of substrate  125  if stacked and pressure is applied against the outer edges of the front side of substrate  125 . 
         [0045]      FIG. 7B  is a bottom perspective view of a variation of the embodiment shown in  FIG. 6 . In this embodiment, release coating  145  is coated on the front side of substrate  125  along perimeter edges  5 - 5 ,  6 - 6 ,  7 - 7 , and  8 - 8 . Release coating  145  allows exposed pressure sensitive adhesive  115  edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4  (as shown in  FIG. 3 ) to easily remove from the front side of substrate  125  if stacked and pressure is applied against the outer edges of the front side of substrate  125 . In order to provide tolerances for misalignments of the sheet assembly when sheets are stacked, release coating edges  5 - 5 ,  6 - 6 ,  7 - 7 , and  8 - 8  are coated wider than the adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4 . 
         [0046]      FIG. 8A  is a bottom perspective view of a variation of the embodiment illustrated in  FIG. 6 , as viewed from the opposite side of either  FIGS. 7A  or  7 B, showing raised element  120  as a solid square. 
         [0047]      FIG. 8B  is a bottom perspective view of another variation of the embodiment illustrated in  FIG. 6 , as viewed from the opposite side of either  FIGS. 7A  or  7 B, showing the raised element  120  as a hollowed square. That is, the raised element  120  does not cover the interior region of the sheet  205 , thereby leaving the substrate  125  exposed in the interior region of the sheet  205 . 
         [0048]      FIG. 9  is a cross-sectional view of a plurality of sheets  205   a - d,  as seen in  FIG. 6 , stacked together to form a pad. Pad  200  includes a plurality of sheets  205   a - d  stacked together in which sheet  205   a  attaches to sheet  205   b,  and sheet  205   b  attaches to sheet  205   c,  and so on, to form a pad when pressure  150  is applied to adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4  (as shown in, for example,  FIG. 8B ) of the front side along release coating edges  5 - 5 ,  6 - 6 ,  7 - 7 , and  8 - 8  (as shown in, for example,  FIG. 7B ) of the substrate  125  of sheet  205   a.  Substrate  125  bearing the adhesive is sufficiently flexible and deformable so that at least a portion of the exposed adhesive along edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4  are brought into contact with the surface to adhere thereto, and so on. When an individual sheet  205   a - d  is needed, release layer  145  allows the sheet  205   a - d  to be peeled away from pad along edges with exposed pressure sensitive adhesive  120 . 
         [0049]      FIGS. 10A-D  show several variations for the embodiment illustrated in  FIG. 3 . In particular,  FIGS. 10A-D  showing various designs for the raised elements  160 ,  165 ,  170 ,  175 . In each of the illustrated embodiments, the sheets  205  are shown with various designs of two or more raised elements  160 ,  165 ,  170 ,  175 .  FIG. 10A  shows raised element  160  in a grid pattern.  FIG. 10B  shows raised element  165  in a solid diamond pattern.  FIG. 10C  shows raised element  170  in a horizontal line pattern.  FIG. 10D  shows raised element  175  in a dashed horizontal pattern. The spacing between raised elements can range from about 2.0 inches or less to allow the sheet to adhere to the application surface but still allow the sheet to slide across an application surface without adhering in the absence of the application of pressure against the front side of the substrate layer. As shown in the diagrams, exposed pressure sensitive adhesive  115  perimeter edges still exist. 
         [0050]      FIG. 11  is a perspective view of another embodiment of the invention. Pad  300  includes a plurality of sheets  305  stacked and attached together at end  180 . Each individual sheet in the pad  300  may include a perforation  185  proximate to end  180 . The securing mechanism of sheet  125  may be similar to sheets in stack  100  described in reference to  FIG. 1 . 
         [0051]      FIG. 12  shows a bottom plan view of one sheet  305  of pad  300 . The sheets in the pad are attached together using mechanical means, such as staples  190 . The sheet assembly is functionally similar to sheets in stack  100 ,  FIG. 1 . 
         [0052]      FIG. 13  is a perspective view of another embodiment of the present invention. In this embodiment, individual sheets  405  are attached to release liner  195  at adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4 , as referenced in  FIG. 3 . Individual sheets  405  are detached from the release liner  195  by peeling the sheet off the liner. Assembly  400  may be in roll format or long sheet format (one long sheet may contain several individual masking sheets). Each masking sheet is functionally similar to sheets in stack  100 ,  FIG. 1 . 
         [0053]      FIG. 14A  is a perspective view of another embodiment of the present invention. In this embodiment, individual sheets  510  are manually separated from roll  500  at perforation  515 . Each sheet assembly is functionally similar to sheets in stack  100 ,  FIG. 1 . 
         [0054]      FIG. 14B  is a perspective view of another embodiment of the present invention. In this embodiment, individual sheets  610  are manually dispensed on a cutting blade  605  from roll  600 . Each sheet assembly is functionally similar to sheets in stack  100 ,  FIG. 1 . 
         [0055]      FIG. 15A-C  show a cross-sectional view of a sheet assembly that allows the masking sheet to manually slide across a mounting surface, such as a window  650 , and when properly aligned into position, easily secure the sheet in place by pressing against the substrates outer edges of the front side of the substrate layer with fingers. 
         [0056]      FIG. 16  is a plan view of the invention showing a single sheet being slid across window glass into a corner of the window. 
         [0057]      FIG. 17  is a plan view of the invention, showing four masking sheets covering the glass in a window frame. 
         [0058]      FIG. 18  is a plan view of another embodiment of the present invention showing masking articles having an L-shape being used to mask the four corners of a window pane. It will be recognized that the adhesive article can be formed into any desirable size or shape, depending on the end use application. Regardless of the size or shape, the masking article may have a function and construction similar to those described herein. 
         [0059]      FIGS. 19A-19C  are plan views of another embodiment of the present invention wherein a release liner  730  acts as the raised element  120 .  FIG. 19A  shows base substrate  125 .  FIG. 19B  is the opposite side of  FIG. 19A  showing release liner  730  with die cut area  740 . Release liner  730  is the same material on either side of die cut area  740 . The release liner material outside the die cut area may be referred to as the outer release liner  750 . The release liner material inside the die cut area may be referred to as the inner release liner  760 .  FIG. 19C  shows outer release liner  750  removed to expose the underlying adhesive  115 , and leaving inner release liner  760  which now becomes raised element  120 . This embodiment allows unattached individual sheets to be easily transportable while protecting adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4 , as referenced in  FIG. 3 . 
         [0060]      FIG. 20A  is a sectional side view of  FIGS. 19B  showing release liner  730  with die cut area  740 . 
         [0061]      FIG. 20B  is a sectional side view of  FIG. 19C  showing outer release liner  730  removed at die cut area  740 , thus exposing adhesive edges  1 - 1 ,  2 - 2 ,  3 - 3 , and  4 - 4 , as referenced in  FIG. 3 , and attached to the adhesive is raised element  120 , which was part of release liner  730 . 
         [0062]    In any embodiment described herein, the substrate or backing layer  125  should be formed of a material that is sufficiently stiff so that it will not curl when detaching a sheet from a stack, a release liner sheet or roll format, nor allow edges of the sheet to flex, drape or sag such that it will contact and grab onto the application surface when sliding the sheet across the surface into proper position. In addition, the substrate  125  should be formed of a material that is sufficiently flexible to allow the exposed adhesive edges to contact the application surface when securing the masking sheet in place by pressing against the adhesive regions edges with fingers. The substrate is generally somewhat deformable, and does not allow paint to creep under the sheets in areas where sheets are shingled or overlapped as shown in  FIG. 17 . Suitable examples of substrate materials include, but are not limited to, paper, synthetic plastic materials, metal foils, and combination thereof. The substrate may have a thickness of 0.0005 inch to about 0.10 inch. In certain embodiment, the sheet assemblies (i.e. the combination of the substrate, the adhesive, and the raised element(s)) may vary from about 1.0 inch to about 36 inches in width, to about 1 inch to about 36 inches in length, depending on the particular end use application. 
         [0063]    The raised elements can be made from a variety of material. Suitable examples include applying ultraviolet (UV) curable or water based coatings, which would form the raised elements. Other suitable materials for the raised element include plastic, paper, or nonwoven materials, where the plastic, paper or nonwoven material is disposed on the pressure sensitive adhesive. Another suitable material for the raised element is tape, where the adhesive side of the tape is disposed on the pressure sensitive adhesive. In certain embodiments, the substrate may have a thickness of at least about 0.005 mm, at least about 0.01 mm, or at least about 0.02 mm, and a thickness of no greater than about 0.4 mm, no greater than about 0.35 mm, or no greater than about 0.3 mm. If the masking article includes more than one raised element per sheet, the spacing between one raised element and an adjacent raised element is generally no greater than about 5 centimeters. 
         [0064]    Suitable pressure sensitive adhesives (PSA) are known to those skilled in the art. The adhesive may be, for example, rubber-based adhesive, acrylic-based adhesive, silicone-based adhesive, polyurethane adhesive, and combinations thereof, and may be solvent based, water based, or can be a solventless, hot melt adhesive. The adhesive may be a repositionable adhesive or a permanent adhesive. 
         [0065]    Persons of ordinary skill in the art may appreciate that various changes and modifications may be made to the invention described above without deviating from the inventive concept. Thus, the scope of the present invention should not be limited to the structures described in this application, but only by the structures described by the language of the claims and the equivalents of those structures.