Patent Publication Number: US-2006019051-A1

Title: Method and system for applying a finely registered printed laminated overlay to a substrate

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application claims priority to U.S. provisional application Ser. No. 60/578,423 filed Jun. 9, 2004, which is herein incorporated by reference. 
    
    
     BACKGROUND  
      1. Field of the Invention  
      The present invention relates to a method and system for laminating a finely registered overlay using a double coated adhesive system, and applying same to a substrate.  
      2. Background of the Art  
      Current technology in this area relies upon printing one or more layers of colored ink (usually white) as a flood coating by screen printing and subsequently drying by convection or ultraviolet (UV) light to produce white background on second surface printed graphics. Such designs are printed primarily on clear polyethylene terephthalate (PET) or polycarbonates (e.g., LEXAN® polycarbonate resin, available from GE Structured Plastics, a division of GE). The graphics and ink printed often require a solid color background to intensify the other printed colors and to provide white areas on which the graphics can be overlaid to provide greater visibility or to incorporate and mask radio frequency identification (RFID) devices under the printed surface.  
      This process is usually followed by the application of a pressure sensitive adhesive by lamination to allow end users to easily adhere the finished graphic or overlay to different substrates such as the control panels for appliances, electronic devices, machinery or vehicles, as well as signs, nameplates, and the like.  
      Users may require indicator lamps, LED (light emitting diode) displays or other types of media to be visible without interference by ink or adhesive. For these areas the removal of white or colored sections and adhesive is required.  
      Presently, adhesive application where certain clear adhesive-free areas are required follows printing and flood coating, this is accomplished by creating a dual liner sheet of the adhesive, die cutting the sheet using a laser or rotary or steel rule dies, removing the excess liner and adhesive, and then removing one layer of release liner and hand registering the resulting die cut sheet to the printed image. Flood coat inks are kept from about 0.010″ to 0.015″ away from the edge of clear areas to allow for mis-registration. Adhesive is often kept at a similar or greater distance to allow for mis-alignment. Off register patterns destroy the workpiece, thereby resulting in undesirable process losses.  
      What is needed is a lamination process wherein flood coating is eliminated and adhesive application results in accurate fine registration to the printed image.  
     SUMMARY  
      A method for applying a printed laminated overlay to a substrate is provided herein. The method comprises (a) providing a first assembly including (i) a first sheet of polymeric material having a coating of adhesive on each of first and second opposite sides, and (ii) a first release liner disposed along the adhesive coating on the first side of the first sheet of polymeric material and a second release liner disposed along the adhesive coating on the second side of the first sheet of polymeric material; (b) providing a second sheet of synthetic polymeric material having a first surface with indicia printed thereon; (c) adhering a peripheral portion of the first side of the first sheet of polymeric material to a peripheral portion of the first surface of the second sheet of synthetic polymeric material; (d) cutting out and removing at least one selected portion of the first assembly to provide at least one aperture therein; (e) removing the first release liner from the first sheet of polymeric material; and, (f) adhering the remainder of the first side of the first sheet of polymeric material to the first surface of the second sheet of polymeric material to provide the laminated overlay. The method further optionally includes (g) removing the second release liner; and (h) affixing the second side of the first sheet of polymeric material to a substrate.  
      The flood coating process is eliminated altogether, replacing both ink and adhesive systems with a double sided adhesive coated carrier film. The adhesives on each side can be the same or different. The carrier film can be colored with various degrees of translucency. The method and system described herein provide consistency of coloration and ease of lamination with precise registration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Various embodiments are described below with reference to the drawings wherein:  
       FIG. 1  is a sectional view of the double coated backing component assembly of the invention;  
       FIG. 2  is a sectional view illustrating attachment of the backing component to a printed overlay sheet;  
       FIG. 3  illustrates kiss cutting of the double coated backing component to create windows;  
       FIGS. 4 and 5  illustrate, respectively, removal of a release liner from the double coated backing component assembly and pressure lamination to the printed overlay sheet to provide a laminated overlay assembly; and,  
       FIG. 6  is a sectional view illustrating registration and attachment between the laminated overlay assembly to a substrate. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)  
      Referring to  FIG. 1 , a backing assembly  100  includes a carrier sheet  110  of synthetic polymer such as polyethylene terephthalate (PET) or polypropylene with adhesive layers  120  and  130  attached thereto on opposite sides of the carrier  110 . The adhesives  120  and  130  are preferably pressure sensitive adhesives, and may be the same or different types of adhesives. Adhesives suitable for use in the invention are well known in the art. The carrier sheet  110  is preferable colored with a solid color, preferably (and most often) white, and can be opaque or translucent. Carrier sheet  110  provides a solid color background to render the printing of the laminated overlay assembly more visible. A first release liner  150  is attached to one adhesive coated side of the carrier sheet and a second release liner  140  is attached to the opposite adhesive coated side of the liner. Sheet  110  is preferably flexible.  
      Referring to  FIG. 2 , a portion of the second liner  140  is removed from peripheral region  102  in the vicinity of the edge of the backing assembly  100 , which is adhered to printed overlay sheet  200  (e.g., to a corresponding peripheral region on sheet  200 ). The peripheral region  102  is typically about ½ inch wide to allow a narrow strip of adhesive to bond to the printed overlay sheet  200 . More particularly, overlay sheet  200  includes a surface  220  containing printed graphics, lettering, numerals, signs or other type of indicia and optionally various colors, and a transparent body portion  210 . Clear body portion  210  of the overlay sheet  200  is preferably uncolored, but may optionally be tinted, provided that the tinting does not obscure visibility or transparency. Printed overlay sheet  200  is preferably fabricated from a flexible film of PET or polycarbonate resin. The backing assembly  100  is attached to printed surface  220  of the overlay sheet  200 . Optionally, printed surface  220  may be provided with areas  221  without any printing, areas  221  being aligned with features of the substrate, as described below.  
      Referring now to  FIG. 3 , the backing assembly  100  is kiss cut to provide apertures  104 A and  104 B ( FIG. 4 ). To accomplish the kiss cutting, dies  301  and  302  cut through layers  150 ,  130 ,  110  and  120  of the backing assembly, but not release liner  140 . The plug sections cut out by the dies  301  and  302  can then be removed to provide the apertures  104 A and  104 B ( FIG. 4 ). These apertures will be oriented with electronic components or other features of a substrate which require visibility and/or multiple intermittent contacts between the overlay sheet  200  and the substrate, and must not contain white backing or adhesive. As shown herein, the windows are optionally aligned with non-printed areas  221  of the printed sheet  200 .  
      Alternatively, the pattern may be die cut or laser cut all the way through the backing assembly  100 . However, this will require a barrier interposed between the backing assembly  100  and the overlay sheet  200  to prevent cutting into the printed surface  220 . Kiss cutting is preferred.  
      Referring now to  FIG. 4 , the second release liner  140  is removed from the backing assembly  100  taking with it residual portions of any adhesive  120  from windows  104 A and  104 B.  
      Referring now to  FIG. 5 , with second release liner  140  fully removed, the remainder of the backing assembly  100  can then be laminated to the printed overlay sheet  200  by, for example, by pressing together through rollers  310 , or by any other suitable means. The pressure sensitive adhesive layer  120  serves as the interface adhesive between the carrier sheet  110  of the backing assembly  100  and the printed surface  220  of the laminated sheet  200  to provide a laminated overlay assembly.  
      Referring now to  FIG. 6 , the laminated overlay assembly can be manually applied to a substrate  400  with accurate registration. The substrate can be a control panel for appliances, automobiles, or electronic devices, or the substrate can be a sign, label, nameplate, container, or any other product having a surface to which a printed laminate is to be applied. As shown in  FIG. 6 , substrate  400  includes a light emitting diode (LED)  410  and a pressure actuated switch  420 , both of which require a window such as  104 A and  104 B. Pressure actuated switch  420  includes an upper electrode layer  421  and a lower electrode layer  423  separated by a spacer  422 . When the upper electrode layer  421  is manually pressed into physical contact with the lower electrode layer  423  (e.g., by finger pressing) electrical current is allowed to flow through the switch  420 , thereby turning on, or off, or controlling some feature of an appliance or electrically controlled equipment. Other electrically operable devices can also be incorporated into the substrate.  
      To apply the laminated overlay assembly, the release liner  150  is removed and the pressure sensitive adhesive layer  130  is placed into contact with the surface of the substrate such that windows  104 A and  104 B are aligned with the appropriate features  410  and  420  of the substrate  400 . As can be seen, the carrier sheet  110  is beneath the overlay sheet  200  and provides a white or solid color background for the printing on surface  220 . Clear body portion  210  provides a protective cover layer. The printed overlay sheet  200  can be easily provided with convex domed portions  205  to facilitate tactile operation of the devices of the substrate aligned therewith.  
      While the above description contains many specifics, these specifics should not be construed as limitations of the invention, but merely as exemplifications of preferred embodiments thereof. Those skilled in the art will envision other embodiments within the scope and spirit of the invention as defined by the claims appended hereto.