Abstract:
A process for applying an adhesion primer to a window. The process includes the steps of directing light ( 11 ) onto the window ( 10 ) to illuminate a portion ( 13 ) of the window and then applying an adhesion primer along the illuminated portion of the window. If the adhesion primer contains a component that evaporates, then the process can further include the step of forming an infrared image ( 19 ) of the window as the component evaporates to indicate the area of application ( 20 ) of the adhesion primer. If the adhesion primer contains a component that fluoresces when illuminated by ultraviolet light, then the process can further include the step of illuminating the window with ultraviolet light ( 22 ) to indicate the area of application ( 23 ) of the adhesion primer.

Description:
RELATED APPLICATION  
       [0001]    The instant application claims the benefit of U.S. Provisional Patent Application No. 60/388,088 filed Jun. 12, 2002. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The instant invention relates to a process for applying an adhesion primer to a window, the adhesion primer to increase the bond strength between the glass of the window and an adhesive or polymer molded to the window, or to increase the bond strength between a paint film on the window and an adhesive or to increase the bond strength between a polymer molded on the window and an adhesive.  
         BACKGROUND  
         [0003]    As discussed in U.S. Pat. No. 5,792,811, the fixed glass windows (such as the windshield) of a modern automobile are bonded to the painted steel body of the automobile using an adhesive (such as a urethane adhesive). The periphery of the window is usually already coated with black cosmetic paint called the “enamel band”. A primer is applied to the enamel band along the area of the window to be bonded to the automobile to improve the strength of the bond between the enamel band and the cured adhesive.  
           [0004]    The area of the enamel band to be primed can be controlled using a mechanical means, such as an edge guide or a template. Alternatively, the area of the enamel band to be primed can be indicated by a pattern printed or otherwise marked on the enamel band. If the primer is applied robotically, then the robot can be programmed to apply the primer to the desired area of the enamel band.  
           [0005]    The primer is often not visually detectable after it has been applied to the enamel band. Thus, it is difficult to determine if an area of the enamel band requiring the primer has been properly primed. It would be an advance in the art of applying an adhesion primer to the enamel band of such a window if a process were developed that indicated the area to be primed and then confirmed that such area had been primed.  
         SUMMARY OF THE INVENTION  
         [0006]    The instant invention provides an improved process for applying an adhesion primer to a window. In addition, the instant invention also provides an improved process for confirming that such area has been primed. More specifically, the instant invention is a process for applying an adhesion primer to a window, comprising the steps of: (a) directing light onto the window to illuminate a portion of the window; (b) applying an adhesion primer along the illuminated portion of the window. If the adhesion primer contains a component that evaporates, then the process can further include the step of forming an infrared image of the window as the component evaporates to indicate the area of application of the adhesion primer. If the adhesion primer contains a component that fluoresces when illuminated by ultraviolet light, then the process can further include the step of illuminating the window with ultraviolet light to indicate the area of application of the adhesion primer. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0007]    [0007]FIG. 1 shows a vehicle windshield being repeatedly scanned with a beam of light to form a luminous line near the edge of the windshield;  
         [0008]    [0008]FIG. 2 shows an adhesion primer being applied to the vehicle windshield of FIG. 1 along the luminous line;  
         [0009]    [0009]FIG. 3 shows a vehicle windshield being inspected with an infrared imaging system; and  
         [0010]    [0010]FIG. 4 shows a vehicle windshield being illuminated by ultraviolet light. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    Referring now to FIG. 1, therein is shown a vehicle windshield  10 . The periphery of the windshield  10  is coated with a black cosmetic paint band  10   a  called the “enamel band”. The window  10  is being repeatedly scanned with a beam of light  11  from a laser light scanner  12 . The laser light scanner  12  repeatedly scans the band  10   a  of the windshield  10  to form a luminous line  13  on the band  10   a.    
         [0012]    Referring now to FIG. 2, therein is shown the vehicle windshield, the beam of light  11 , the laser light scanner  12  and the luminous line  13  of FIG. 1. An adhesion primer applicator  14  is shown being used to apply a band  15  of an adhesion primer along the luminous line  13 . The applicator  14  can be manually manipulated or the applicator  14  can be manipulated by a robot programmed to follow the line  13 .  
         [0013]    Referring now to FIG. 3, therein is shown the windshield  10  of FIG. 2 after the adhesion primer has been applied. The adhesion primer contains a solvent that evaporates after the adhesion primer has been applied. The evaporation of the solvent cools the area of the windshield  10  where the adhesion primer was applied. An infrared camera system  16 , electrically connected to a monitor  17  by wires  18 , is directed at the windshield  10  to form an infrared image  19  of the windshield  10 . The infrared image  19  of the windshield  10  shows the band of drying adhesion primer as a region  20  of the infrared image  19  of lower temperature. The infrared imaging system shown in FIG. 3 is used as a quality control check to confirm the proper application of the adhesion primer.  
         [0014]    Referring now to FIG. 4, therein is shown the windshield  10  of FIG. 2 after the adhesion primer has been applied. The adhesion primer contains a fluorescing component that fluoresces when illuminated by ultraviolet light. A source of ultraviolet light  21  is used to direct ultraviolet light  22  at the windshield  10  causing the fluorescing component of the band of adhesion primer on the windshield  10  to fluoresce and be apparent as a region  23  on the windshield  10 . The ultraviolet illuminating system shown in FIG. 4 is used as a quality control check to confirm the proper application of the adhesion primer.  
         [0015]    Referring again to FIG. 1, the laser light scanner  12  can be the system described in PCT Patent Application WO 01/82634 A2 (PCT/US01/12751 claiming priority to U.S. patent application Ser. No. 09/553,235 filed Apr. 19, 2000). Such a laser light scanner can be readily programmed to scan a contoured glass object such as a vehicle windshield. However, it should be understood that any suitable system can be used to direct light onto the glass object to illuminate and make apparent the portion of the glass object to be treated. For example, a digital “slide show” projector can be used in combination with a general purpose digital computer programmed, for example, in Microsoft PowerPoint brand projection software, such a combination configured to illuminate the desired portion of the window to be treated with the adhesion primer. An additional important benefit of the instant invention is the capability of projecting a unique indicia (such as an array of dots or other geometric shapes) at various points on the enamel band of a window to correspond with indicia printed or otherwise indicated on the enamel band of the window (such as by a void in the enamel band) to confirm proper location of the window relative to the light projector or scanner and/or to confirm the proper specification of the window to be primed.  
         [0016]    Much of the description above related to the application of an adhesion primer to a vehicle windshield. However, it should be understood that other glass treatments can be used in the instant invention. For example, the glass treatment can be cleaning to remove, for example, oil and grease. The glass object to be treated can be of any shape. An adhesion primer is defined herein as a composition that is applied to the enamel band (or to bare glass) to increase the strength of the bond between the enamel band (or the bare glass) and the cured adhesive as determined by SAE test J 1529 or ASTM test D 1002.  
         [0017]    The glass object to be treated can also be “encapsulated”, for example a window having a polymer molded to the window at the periphery of the window. The window can be treated according to the instant invention with an adhesion primer to increase the strength of the bond between the glass and the cured polymer. Thus, the term adhesion primer is also defined herein as a composition that is applied to the window to increase the strength of the bond between the glass and the cured polymer as determined by SAE test J 1529 or ASTM test D 1002. And, the exposed cured polymer portion of an encapsulated window can then in turn be treated according to the instant invention with an adhesion primer to increase the strength of the bond between the cured polymer and an adhesive used to bond the encapsulated window to an automobile body. Thus, the term adhesion primer is also defined herein as a composition that is applied to at least a portion of the cured polymer of an encapsulated window to increase the strength of the bond between the cured polymer and the cured adhesive as determined by SAE test J 1529 or ASTM test D 1002.  
         [0018]    The specific infrared imaging system and the specific ultraviolet light illuminating system used are not critical in the instant invention. The infrared imaging system and the ultraviolet light illuminating system of the instant invention are readily available from numerous sources, for example Edmund Industrial Optics, Barrington, N.J. (USA). As a specific example, the infrared imaging system can be the Model 760 system available from Inframetrics, Inc., Billerica, Mass. (USA). The ultraviolet light illuminating system can be a Blak-Ray brand model B 100A ultraviolet lamp assembly available from the Entela Co., Upland, Calif. (USA).  
         [0019]    Fluorescing components are readily available from numerous sources, for example Aldrich Chemical Co., Milwaukee Wis. As a specific example, the fluorescing component can be Uvitex OB brand fluorescing agent available from Ciba Specialty Chemicals, Tarrytown, N.Y. (USA). The amount of fluorescing agent added to the adhesion primer must be sufficient so that the area of the window treated with the primer is apparent when the window is illuminated with the ultraviolet light. As a specific example, Betaseal 43518 brand adhesion primer available from The Dow Chemical Company, Midland, Mich. (USA) can contain 0.05 weight percent of Uvitex OB brand fluorescing agent. The specific evaporating solvent used in the adhesion primer is not critical in the instant invention as long as the solvent evaporates at a rate sufficient to cause a degree of cooling sufficient to be detectable using the infrared imaging system. As a specific example, Betaseal 43518 brand adhesion primer available from The Dow Chemical Company, Midland, Mich. (USA) already contains such a solvent.  
       EXAMPLE 1  
       [0020]    A Kodak DCS Pro 14n model digital camera and a Sony model SVGA VPL-CS1 LCD projector are mounted above an adhesive application workstation. The protective packaging is removed from a quarter glass widow for a 2003 Ford Mustang (Harmon Auto Glass, Minneapolis, Minn. (USA)) and the window is positioned on the locator jig of the workstation. A general purpose digital computer equipped with an Intel Pentium 4 brand processor, programmed with Microsoft Windows XP brand operating system and Windows PowerPoint brand projection software, is connected to the projector and the camera. The image from the digital camera is downloaded into the computer and used to program the Windows PowerPoint brand projection software to project a ten point green line around the periphery of the window where it is desired to apply an adhesion primer to the window.  
         [0021]    A Dow Automotive aftermarket replacement glass wool dauber (available from The Dow Chemical Company, Midland, Mich. (USA)) is saturated with Dow Betaseal 43518 brand clear adhesion primer and used to manually apply the primer along the line projected on the window. The primed area of the window is then wiped with a lint-free cloth and Dow Betaseal 43520A brand blackout primer is applied along the line projected on the window using a two and one half centimeter wide natural hair brush. Then, Dow Betaseal 57302 brand adhesive is applied along the line projected on the window using a Milwaukee model 6550-20 caulking gun (available from Milwaukee Tool Works, Brookfield, Wis. (USA)). The window is removed from the workstation and bonded to the quarter glass window opening of a 2003 Ford Mustang.  
       EXAMPLE 2  
       [0022]    A Kodak DCS Pro 14n model digital camera, a Sony model SVGA VPL-CS1 LCD projector and a Blak-Ray model B 100A UV lamp are mounted above an adhesive application workstation. The protective packaging is removed from a quarter glass widow for a 2003 Ford Explorer SUV (Harmon Auto Glass, Minneapolis, Minn. (USA)) and the window is positioned on the locator jig of workstation. A general purpose digital computer equipped with an Intel Pentium 4 brand processor, programmed with Microsoft Windows XP brand operating system and Windows PowerPoint brand projection software, is connected to the projector and the camera. The image from the digital camera is downloaded into the computer and used to program the Windows PowerPoint brand projection software to project a ten point green line around the periphery of the window where it is desired to apply an adhesion primer to the window.  
         [0023]    Twenty five milligrams of Uvitex OB brand fluorescing agent (Ciba Geigy) is mixed with one hundred grams of Dow Betaseal 43518 brand clear adhesion primer and manually applied along the line projected on the window. The primed area of the window is apparent by the blue-white florescence of the primed area. Dow Betaseal 57302 brand adhesive is applied along the line projected on the window using a Milwaukee model 6550-20 caulking gun. The window is removed from the workstation and bonded to the quarter glass window opening of a 2003 Ford Explorer.  
       EXAMPLE 3  
       [0024]    Kodak DCS Pro 14n model digital camera, a Sony model SVGA VPL-CS1 LCD projector and An Inframetrics Model 760 infrared camera system are mounted above an adhesive application workstation. A windshield for a 2003 Ford F250 pickup truck (Harmon Auto Glass, Minneapolis, Minn. (USA) is positioned on the locator jig of an adhesive application workstation. A general purpose digital computer equipped with an Intel Pentium 4 brand processor, programmed with Microsoft Windows XP brand operating system and Windows PowerPoint brand projection software, is connected to the projector and the camera. The image from the digital camera is downloaded into the computer and used to program the Windows PowerPoint brand projection software to project a ten point green line around the periphery of the windshield where it is desired to apply an adhesion primer to the windshield.  
         [0025]    Dow Betaseal 43518 brand clear adhesion primer is manually applied along the line projected on the windshield. The primed area of the windshield is apparent in the monitor of the infrared camera system by the color change of the primed area as the primer dries (especially when using the image subtraction feature of the infrared camera system). Dow Betaseal 57302 brand adhesive is applied along the line projected on the windshield using a Milwaukee model 6550-20 caulking gun. The windshield is removed from the workstation and bonded to the windshield opening of a 2003 Ford F250 pickup truck.