Abstract:
A laminate is provided for forming an aesthetically pleasing fire worthy exterior surface on an object, for example a decorative interior sidewall used in a commercial aircraft. A first film layer forms an exterior surface of the sidewall, and an ink layer is disposed adjacent to the first film layer to provide color and/or images in an aesthetically pleasing manor, and to protect the subsequent layer from damaging UV light exposure. An embossing resin layer is disposed adjacent to the ink layer to improve the fire worthiness of the laminate by being situated adjacent to the exterior surface of the laminate. A second film layer is disposed adjacent to the embossing resin layer and a surface of the sidewall. The location of the embossing resin layer enhances the fire worthiness of the laminate by operating to absorb thermal energy released by the sidewall in the event the sidewall is exposed to fire or to a high temperature sufficient to otherwise cause higher thermal energy release of a conventional laminate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is related in general subject matter to pending U.S. patent application Ser. No. 10/882,047, filed Jun. 30, 2004, assigned to The Boeing Company, and hereby incorporated by reference into the present application. Additionally, the subject matter of the present application claims priority from U.S. Provisional Patent Application Ser. No. 60/688,414, filed Jun. 8, 2005, entitled “Method and Apparatus for Forming a Laminate with Improved Fire Worthiness,” the disclosure of which is also hereby incorporated by reference into the present application, and U.S. Provisional Patent Application Ser. No. 60/688,413, filed Jun. 8, 2005, entitled “Method and Apparatus for Forming Fireworthy Laminate.” 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to laminates, and more particularly to a system and method for forming laminates with improved fire worthiness. 
     BACKGROUND OF THE INVENTION 
     Certain mobile platforms, such as aircraft, trains and automobiles, may generally employ laminate structures to form various surfaces. Laminate structures serve to provide visually appealing surfaces to the objective viewer. For example, in a commercial aircraft, a plurality of laterally aligned overhead stowage bin doors is typically included along the port and starboard sides of the passenger cabin of the aircraft. These stowage bin doors each generally include a laminate disposed on the front of the stowage bin door to create a visually appealing interface for the customer. Further, the sidewalls or other monuments in the passenger cabin may be lined with laminates to create a lightweight visually appealing surface. Advantageously, these laminates used for the sidewalls may also include patterns or other visually pleasing images. In addition, many other surfaces may be coated with a laminate to increase the visual appeal of the surface, such as doors, ceiling tiles and the like. Further, in some instances, laminates may also be used to display information to potential viewers, such as safety hazards or use instructions. 
     As many mobile platforms are subject to fire worthiness standards, it would be advantageous if the laminates could absorb thermal energy in the event of a fire. Such laminates could be affixed to any desired structure to reduce the amount of thermal energy released by the desired structure during a combustion event. Thus, the laminates may increase the fire worthiness of the desired structure while providing an aesthetically pleasing surface. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a laminate for forming an aesthetically pleasing, fire worthy exterior surface on an object, and is ideally suited for interior use in various mobile platforms and especially in commercial aircraft. The laminate comprises a first film layer which forms an exterior surface of the laminate. An ink layer is disposed adjacent the first film layer. An embossing resin layer is disposed adjacent the ink layer, to be proximate to the exterior surface of the laminate. A second film layer is disposed adjacent the embossing resin layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a simplified perspective view of a portion of an interior passenger cabin area of a commercial aircraft illustrating a laminate disposed on a sidewall and additionally on a plurality of overhead stowage bin doors of the interior passenger cabin, in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is a perspective, enlarged view of a sidewall including a laminate according to the principles of the present invention; 
         FIG. 3  is a side, cross sectional view of the surface of  FIG. 2  taken in accordance with section line  3 - 3  in  FIG. 2  showing the various layers of a fixed laminate secured to the sidewall; 
         FIG. 4  is a side, cross sectional view of the sidewall of  FIG. 2  taken in accordance with section line  3 - 3  in  FIG. 2  showing the various layers of the fixed laminate of  FIG. 1  according to an alternate embodiment; 
         FIG. 5  is a side, cross sectional view of the sidewall of  FIG. 2  taken in accordance with section line  3 - 3  in  FIG. 2  showing the various layers of the fixed laminate of  FIG. 3  according to a second alternate embodiment; 
         FIG. 6  is a side, cross sectional view of the sidewall of  FIG. 2  taken in accordance with section line  3 - 3  in  FIG. 2  showing the various layers of the fixed laminate of  FIG. 3  according to a third alternate embodiment; and 
         FIG. 7  is a side, cross sectional view of the sidewall of  FIG. 2  taken in accordance with section line  3 - 3  in  FIG. 2  showing the various layers of the fixed laminate of  FIG. 3  according to a fourth alternate embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring to  FIGS. 1 and 2 , there is shown a laminate  10 . The laminate  10  may form an outer surface  12  of a suitable structure such as a panel or sidewall  14  on a mobile platform  8 , however, the laminate  10  may be applied to the surface of any structure desiring an aesthetically pleasing surface such as a stowage bin door  15 . In this example, the mobile platform comprises a commercial aircraft having a fuselage with an interior area  8   a , seats  8   b , ceiling panels  8   c , a floor (not visible in the figure), etc. It will be appreciated that laminate  10  could be used to help form a variety of structural or decorative panels able to be used in a mobile platform, such as a train, automobile or aircraft, or even in a fixed (i.e., non-mobile) structure. 
     With reference now to  FIG. 3 , laminate  10  is comprised of a first film layer  16 . The first film layer  16 , in one preferred form, comprises a very thin polyvinyl fluoride film, such as Tedlar® PVF film, having a thickness of preferably about one mil. The first film layer  16  is also preferably a clear gloss or a semi-gloss layer, but in either event it is substantially translucent or clear. Adjacent to the first film layer  16  is an ink layer  18 . 
     Ink layer  18  represents the ink that may comprise an image  19 . The ink layer  18  is formed on an inside surface  16   b  of the first film layer  16 . This eliminates the need to place a protective, separate layer over the ink layer  18 , since the first film layer  16 , itself, forms a protective covering for the ink on its inside surface  16   b . Ink layer  18  may be comprised of opaque, metallic or pearlescent ink which may be deposited by a suitable print technology, and more preferably by screen printing. Also, since the ink layer  18  is deposited on the inside surface  16   b , it will be appreciated that the image  19  will need to be transposed during the printing process so that it appears correct when being viewed from the opposite side (i.e., outer surface  16   a ) of first film layer  16 . 
     The laminate  10  further includes a layer  24  comprised of an embossing resin and a second film layer  26 . The second film layer  26  preferably comprises a very thin polyvinyl fluoride film, such as Tedlar® PVF film, having a thickness of preferably around two mils. Second film layer  26  is preferably white in color. The layer of embossing resin  24  may vary significantly, but in one preferred form comprises an areal weight of 0.023 pounds/square foot (lb/ft 2 ) to 0.031 lb/ft 2 . 
     The laminate  10  is formed in a conventional multi-opening press which uses heat and pressure to consolidate the individual layers making up laminate  10  together as a single, decorative, laminate structure. A texture of some kind may be imparted into the laminate as to be clearly visible on outer surface  16   a  of the first film layer  16 . The texture is maintained by the embossing resin of layer  24  as the resin cures in the multi-opening press during manufacture. 
     With reference to Table 1 below, test data is shown illustrating the improved fire worthiness of the laminate  10  incorporating the embossing resin layer  24  adjacent to the ink layer  18 . The samples below were tested according to Ohio State University Heat Release Test Method. There are two main requirements for federal fire worthiness, the peak release value must be below 65 kilowatts per square meter (kW/sq meter), and the two minute total heat released must be below 65 kilowatt minute per square meter (kW-min/sq meter). The values below are given in percent reduction in heat release as compared to baseline laminates. Baseline 1 is a laminate similar to laminate  10  except layer  24  and  26  are transposed (layer  26  is now in contact with ink layer  18 ) and the first film layer  16  has a heat seal adhesive applied to inside surface  16   b . Baseline 2 is similar to Baseline 1 except for the addition of another film layer (third film layer) disposed to the outside surface of embossing layer  24 . The third film layer is the same material as layer  26 . Values are given for a laminate  10  incorporating a second film layer  26  (indicated as “NG-Dec” in Table 1) formed of polyvinyl fluoride film, such as a Tedlar® PVF film (PVF), fluorinated ethylenepropylene (FEP), or tetrafluoroethylene, hexaflouropropylene and vinylidene fluoride (THV™) as will be described in greater detail below. 
     
       
         
               
             
               
               
               
             
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Test Data for Laminate Panel with Embossing Resin Layer Adjacent to 
               
               
                 First Film Layer 
               
             
          
           
               
                   
                 OSU Peak 
                 OSU 2-min 
               
               
                   
                 Heat Release 
                 Total Heat Release 
               
               
                 Laminate 
                 (% Reduction 
                 (% Reduction 
               
               
                 Construction 
                 From Baseline) 
                 From Baseline) 
               
             
          
           
               
                 (Back Film) 
                 Baseline 1 
                 Baseline 2 
                 Baseline 1 
                 Baseline 2 
               
               
                   
               
             
          
           
               
                 NG-Dec (PVF) 
                 16.4 
                 19.0 
                 18.2 
                 22.4 
               
               
                 NG-Dec (FEP) 
                 36.1 
                 38.1 
                 36.4 
                 39.7 
               
               
                 NG-Dec (THV) 
                 44.3 
                 46.0 
                 41.8 
                 44.8 
               
               
                   
               
             
          
         
       
     
     Thus, by placing the embossing resin layer  24  closer to a possible source of flame (i.e., the outside surface  16   a  of the laminate  10 ) the embossing resin layer  24  serves to slow the combustion process and reduce the intensity of the burn, resulting in a reduced heat release value for the laminate  10 . 
     The decorative textured laminate  10  may then be secured to the desired outer surface  12  through various techniques, such as the use of spray adhesive, layer  28 , applied to the outer surface  12  and through the use of an infrared (IR) oven to form the laminate  10  to the outer surface  12  of sidewall  14 . Some trimming of excess material or edge wrapping of laminate  10  may be required to achieve maximum aesthetic appeal. 
     An alternate composition of the laminate  10  is shown as laminate  20  in  FIG. 4 . As only the composition of the second film layer  126  has been altered, only this feature will be discussed. The second film layer  126  may comprise tetrafluoroethylene, hexaflouropropylene and vinylidene fluoride (THV™) to further reduce the heat released by the laminate  10 . The use of THV™ film reduces the heat released by the laminate  10  because the chemical composition of the THV™ film creates a material with desirable physical properties while providing a high Limiting Oxygen Index (LOI) material. The LOI is a measurement of the minimum percentage of oxygen required to sustain ignition and combustion. Generally, materials with a high LOI, such as an LOI of greater than 30 percent, are considered to be self-extinguishing polymers. THV™ film generally has a LOI greater than 75%. 
     The second film layer  126  may generally be opaque, white, and generally has a thickness of two mils, however, slight variation in thickness and color may be employed. Similar to the laminate  10 , the second film layer  126  may be disposed adjacent to the embossing resin layer  24 , and the alternative laminate  20  may also be formed in substantially the same way as the laminate  10 . 
     A second alternate composition of the laminate  10  is shown as laminate  30  in  FIG. 5 . As only the composition of the second film layer  226  has been altered, only this feature will be discussed. The second film layer  226  may comprise fluoroethylene-propylene (FEP) to further reduce the heat released by the laminate  10 . The use of FEP film reduces the heat released by the laminate  10  because the chemical composition of the FEP film creates a material with desirable physical properties while providing a high Limiting Oxygen Index (LOI) material. The LOI is a measurement of the minimum percentage of oxygen required to sustain ignition and combustion. Generally, materials with a high LOI, such as an LOI of greater than 30 percent, are considered to be self-extinguishing polymers. FEP film generally has a LOI greater than 95%. 
     The second film layer  226  may generally be opaque, white, and generally has a thickness of two mils, however, slight variation in thickness and color may be employed. Similar to the laminate  10 , the second film layer  226  may be disposed adjacent to the embossing resin layer  24 , and the alternative laminate  30  may also be formed in substantially the same way as the laminate  10 . 
     With reference now to  FIG. 6 , a third alternate laminate  40  is shown. The laminate  40  is similar to laminate  10 . The laminate  40  includes a first film layer  116  having a first side  116   a  which forms the outside surface of the laminate  40 . The first film layer  116  is generally comprised of substantially transparent polyvinyl fluoride film, such as a Tedlar® PVF film, having a thickness of approximately one mil and including an ultraviolet (UV) blocker. Adjacent to the first film layer  116  may be an ink layer  118 . The ink layer  118  may be used to form the image  19  on the laminate  40 , however, the ink layer  118  is optional. If included in the formation of the laminate  40 , then the ink layer  118  may be comprised of UV cured ink jet ink which may be printed on a second side  116   b  of the first film layer  116  using any appropriate ink jet printer. 
     The ink used to form ink layer  118 , which makes up the image  19 , preferably comprises an ultraviolet (UV) curable and stable ink (black or colored) that is deposited directly on the first film layer surface  116   b . The ink is cured virtually immediately after being deposited by the ink jet printer via a UV light associated with the digital ink jet printer that passes over the newly deposited ink just after the ink is deposited. The use of UV curable ink allows the ink to be deposited directly on the first film layer  116  without the need for some type of receptive coating to be placed over the first film layer  116 , which would be necessary with water or solvent based digital ink jet inks. The ability of the UV curable ink to be cured virtually immediately after being deposited on the first film layer also simplifies and expedites the manufacturing of the laminate  40 . In addition, UV curable inks allow ink loadings on the Tedlar® PVF in excess of 300% which is difficult, or impossible, to obtain using water or solvent based digital ink jet inks. 
     The laminate  40  further includes a layer  24  comprised of an embossing resin and a second film layer  26 . The second film layer  26  also preferably comprises a very thin polyvinyl fluoride film, such as Tedlar® PVF film, having a thickness of preferably around two mils. Second film layer  26  is also preferably white in color. The layer of embossing resin  24  may vary significantly, but in one preferred form comprises an areal weight of 0.023 pounds/square foot (lb/ft 2 ) to 0.031 lb/ft 2 . 
     As described above, the ink layer  118  is most preferably applied by a suitable ink jet printer or printing process. Companies making suitable ink jet printers or printing equipment are Vutek of Meredith, N.H. and Leggett &amp; Platt Inc. of Jacksonville Beach, Fla. Other suitable inks are available from 3M Corp. of Minneapolis, Minn., and Sunjet of Bath, England. The color image formed by the image  19 , in one preferred form, comprises a high contrast color image which is highly aesthetically pleasing to view. 
     If the ink layer  118  is employed in the formation of the laminate  40 , then an embossing resin layer  24  may be positioned adjacent to the ink layer  118 . Otherwise, the embossing resin layer  24  may be disposed against the first film layer  116 . As the embossing resin layer  24  generally includes a fire retardant material as part of the formulation of the embossing resin, the embossing resin layer  24  may be layered closer to the outside surface  116  of the laminate  40  to improve the heat resistance of the material, as discussed previously. The embossing resin layer  24  may further be preferably white or opaque in color as the ink jet printing is a subtractive printing process which requires an opaque or white background to create the image  19 . In addition, the use of the UV blocker in the first film layer  116  further serves to protect an ink jet printed image as without the UV blocker in the first film layer  116 , the exposure of the laminate  40  to UV light may cause the embossing resin layer  24  to yellow over time. 
     The embossing resin layer  24  may be disposed adjacent to a second film layer  26 . The second film layer  26  may generally comprise opaque or white polyvinyl fluoride film, such as a Tedlar® PVF film, having a thickness of approximately two mils. 
     The laminate  40  is formed in a conventional multi-opening press which uses heat and pressure to consolidate the individual layers making up laminate  40  together as a single, decorative, laminate structure. A texture of some kind may be imparted into the laminate as to be clearly visible on outer surface  116   a  of the first film layer  116 . The texture is maintained by the embossing resin of layer  24  as the resin cures in the multi-opening press during manufacture. 
     With reference to  FIG. 7 , a fourth alternate composition laminate  50  is shown. The alternative composition laminate  50  is substantially similar to the laminate  40 , except the second film layer  126  is comprised of different material. Thus, only the altered composition will be discussed. The alternative composition laminate  50  includes a second film layer  126 . The second film layer  126  may comprise tetrafluoroethylene, hexaflouropropylene and vinylidene fluoride (THV™) to further reduce the heat released by the laminate  40 . The use of THV™ film reduces the heat released by the laminate  40  because the chemical composition of the THV™ film creates a material with desirable physical properties while providing a high Limiting Oxygen Index (LOI) material. The LOI is a measurement of the minimum percentage of oxygen required to sustain ignition and combustion. Generally, materials with a high LOI, such as an LOI of greater than 30 percent, are considered to be self-extinguishing polymers. THV™ film generally has a LOI greater than 75%. 
     While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.