Patent Publication Number: US-2022234427-A1

Title: Composite material vehicle component construct

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority of U.S. Provisional Patent Application Ser. No. 62/859,796 filed Jun. 11, 2019, which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention in general relates to composite materials and in particular to a vehicle door or body component formed with a composite open area core sandwich structure and a window formed of a transparent resin. 
     BACKGROUND OF THE INVENTION 
     Lightweight and heavy duty all terrain and all-purpose vehicles, such as vans and sport utility vehicles have become increasingly popular for both business and personnel use. These vehicles are typically equipped with a liftgate or rear hatch door that opens and closes to expose and enclose a trunk space or cargo compartment of the vehicle. Additionally, some such vehicles include sliding side doors that slide on a track to open and close to expose and enclose portions of the passenger compartment of the vehicle. Typical liftgates, doors, and body panels also form structural body components of the vehicle, providing energy absorption and impact resistance in rear or side impact crashes, respectively. Typical liftgates, doors, and body panels are formed of aluminum or steel, in order to provide the high strength that is required of vehicle structural parts. Typical liftgates, doors, and body panels additionally often include a window through which a driver is able to see. Such windows are formed of glass, such as laminated glass which is formed to two layers of glass with a thin layer of vinyl therebetween. The windows are formed separately and subsequently attached to frame structure that forms the liftgate, door, or body panel. 
     Weight savings in the automotive, transportation, and logistics-based industries has been a major focus in order to make more fuel-efficient vehicles. In order to achieve weight savings in vehicles, light weight composite materials have been introduced to take the place of typical metal structural and surface body components and panels. Composite materials are materials made from two or more constituent materials with significantly different physical or chemical properties, that when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure. A composite material may be preferred for many reasons: common examples include materials which are stronger, lighter, or less expensive when compared to traditional materials. 
     A sandwich-structured composite is a special class of composite material that is fabricated by attaching two thin but stiff skins to a lightweight but thick core. The core material is normally a low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density. While sandwich structures have previously been developed to provide strength and reduced weight, the ability to obtain a vehicle exterior quality high gloss surface has remained a challenge, regardless of whether the surface outermost layer is thermoset resin or thermoplastic. Exemplary of these efforts are U.S. Pat. Nos. 5,087,500A; 4,803,108A; 8,091,286B2; 4,369,608A; 3,553,054A; and WO2018/202473. It is conventional to either not use such sandwich structures in settings where vehicle high surface gloss is required, for example, liftgates, doors, and body panels, or resort to an additional outer layer to provide a high gloss outermost layer. Such outermost layers can be applied after structure production or through in mold coatings, both of which add to the cost and complexity of production. 
     Still another conventional problem with sandwich structures is that the edges are ineffective and allow for infiltration of humidity or moisture that becomes entrained within the core and often inconsistent with finished vehicle surface requirements. With temperature extremes this entrained moisture can reduce the operational lifetime of the structure, while increasing the weight thereof. These problems of moisture infiltration are particularly pronounced in instances when the core is formed of cellulosic materials such as paper. Accordingly, such composite sandwich structures have been unsuitable for forming liftgates and doors given that such areas of a vehicle are exposed to the elements. 
     Even when liftgates, doors, and body panels are formed of light weight composite materials, the glass window portions are heavy, thereby limiting the amount by which the weight of such components may be reduced. Additionally, the windows being formed separately from the structure of the liftgate, door, or body panel and thus requiring a separate joining or attachment step in order to form a completed liftgate, door, or body panel results in low manufacturing throughputs, added costs, and added tooling. 
     Thus, there exists a need for a light weight, high strength vehicle component construct formed of light weight composite materials having a window section formed by streamlined manufacturing processes with increased manufacturing throughputs and reduced costs. 
     SUMMARY OF THE INVENTION 
     The present invention provides a light weight, high strength vehicle component construct formed of light weight composite materials having a window section formed by streamlined manufacturing processes with increased manufacturing throughputs and reduced costs. According to embodiments, an inventive vehicle component construct includes a frame formed of a composite sandwich panel material and a window formed of a transparent resin within the frame. The composite sandwich panel material of the frame includes an open area core defining a plurality of pores, a high gloss surface sheet adhered to a first face of the open area core by a first adhesive layer, and a structural skin adhered to a second face of the open area core by a second adhesive layer. The frame defines a through opening that extends from an exterior surface of the frame to an oppositely opposed interior surface of the frame. The window is formed within the through opening of the frame. According to embodiments, the vehicle component construct is a tailgate, liftgate, or hatch door of a vehicle. 
     The present invention also provides a process for forming the inventive vehicle component construct described. The process includes placing a sheet of the composite sandwich panel material in a mold, cutting the sheet of composite sandwich panel material into a predetermined shape of the frame, and injecting a transparent resin into the mold to form the window in the through opening of the frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is further detailed with respect to the following drawings that are intended to show certain aspects of the present invention but should not be construed as a limit on the practice of the present invention. 
         FIG. 1  is a rear perspective view of a vehicle featuring several embodiments of an inventive vehicle component construct; 
         FIG. 2  is a rear perspective view of the vehicle of  FIG. 1  with a liftgate or tailgate according to embodiments of the present invention in an opened position; 
         FIG. 3  shows a perspective view of an inventive vehicle component construct according to embodiments of the present invention; 
         FIG. 4  is a partial cutaway, perspective view of a composite sandwich panel material used to form embodiments of the inventive component construct; 
         FIG. 5  is an enlarged partial cutaway, side view of the composite sandwich panel material of  FIG. 4  along a line bisecting the hexagonal pores; 
         FIGS. 6A-6D  are cross-sectional views of edges of a composite sandwich panel material; and 
         FIG. 7  is a partial cutaway, perspective view of a composite sandwich panel material containing a conduit used to form embodiments of the inventive component construct. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     The present invention has utility as a light weight, high strength liftgate, door, or body panel construct formed of light weight composite open area core sandwich structure, formed by streamlined manufacturing processes with increased manufacturing throughputs and reduced costs. The use of the composite sandwich structure allows for replacement of traditional materials such as steel or aluminum, without a loss of strength. Additionally, the present invention has utility as a liftgate, door, or body panel construct having a transparent window section simultaneously formed therein to further reduce the weight of the liftgate, door, or body panel construct while also improving manufacturing cycle time and throughput. 
     According to embodiments, a liftgate, door, or body panel construct is formed of a sandwich composite structure as detailed in co-pending U.S. Provisional Patent Application No. 62/774,600, filed on Dec. 3, 2018, the contents of which are hereby incorporated by reference. As described therein, embodiments of the sandwich composite structure provide a high gloss surface sheet and structural skin that are adhered to the open area core with an adhesive or glue that is viscous when applied. The viscosity of the adhesive as applied allows for contact with the interior volume of the open area core to create more adhesion surface area yet without excessively running into the pores defined in the open area core before the adhesive cured or hardens thereby providing greater adhered contact area between the components of the sandwich composite structure. As a result, reduced delamination of the components of the sandwich composite structure is observed as well as precluding bond line readthrough into the high gloss surface sheet. It is appreciated that providing a high gloss exterior surface without resort to an additional outmost layer requires a balancing of opposing surface tension properties of the composite sandwich panel structures to avoid a loss in tolerances associated with bowing of the structure. Embodiments of the present invention also have utility as watertight and waterproof composite sandwich panel structures. 
     The present invention will now be described with reference to the following embodiments. As is apparent by these descriptions, this invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. For example, features illustrated with respect to one embodiment can be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from the embodiment. In addition, numerous variations and additions to the embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure, which do not depart from the instant invention. Hence, the following specification is intended to illustrate some particular embodiments of the invention, and not to exhaustively specify all permutations, combinations, and variations thereof. 
     It is to be understood that in instances where a range of values are provided that the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of the range. By way of example, a recited range of from 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4. 
     Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. 
     Unless indicated otherwise, explicitly or by context, the following terms are used herein as set forth below. 
     As used in the description of the invention and the appended claims, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. 
     Also as used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative (“or”). 
     As used herein, the term “high gloss surface” refers to a surface having minimal perceptible surface defects when visually inspected for about three seconds from about 24-28 inches from the viewer and normal to the part surface +/−90 degrees in a well-lit area. That is, the term “high gloss surface” refers to a surface capable of being painted and accepted as a “Class A” autobody part. This is commonly measured by ASTM D523. In the automotive industry, a Class A surface is a surface a consumer can see without functioning the vehicle (e.g., opening the hood or decklid), while a Class A surface finish generally refers to painted outer panels and specifically to the distinctness of image (DOI) and gloss level on the part. It is appreciated that a surface layer may be subjected to sanding, trimming, and priming prior to receiving a paint coating that imparts high gloss, yet must retain dimensionality and adhesion uniformity to primer and paint so as to achieve a high gloss finish. 
       FIGS. 1 and 2  show rear perspective views of a vehicle  50  featuring several embodiments of an inventive vehicle component construct  52 ,  52 ′,  52 ″,  52 ′″,  52 ″″. According to embodiments, the inventive vehicle component construct is a tailgate, liftgate, or hatch door  52 ; a sliding door  52 ′; a body panel  52 ″,  52 ″″; or a roof panel  52 ′″, for example having a moon roof. For the sake of clarity in the figures, reference numerals regarding the features of embodiments of the inventive vehicle component construct are generally shown with regard to vehicle component construct  52 , unless otherwise indicated; however, it will be understood that the described and referenced features may be present in all of the embodiments of the inventive vehicle component construct  52 ,  52 ′,  52 ″,  52 ′″,  52 ″″. According to embodiments, an inventive vehicle component construct includes a frame  54  formed of a composite sandwich panel material  10  and a window  56 . The frame  54  has an exterior surface  58  and an oppositely opposed interior surface  60 . The frame  54  defines a through opening  62  therein that extends from the exterior surface  58  of the frame  54  to the interior surface  60  of the frame  54 . The window  56  is formed within the through opening  62  of the frame  54 . The window  56  is formed of a transparent material, such as a transparent resin or glass 
     According to embodiments, the window  56  is formed by injection molding. In such embodiments, a transparent resin that forms the window  56  is injected into a mold, preferably the same mold that is used to form the shape of the frame  54 . Thus, the entire vehicle component construct is capable of being formed as a single unit from a single mold or manufacturing device. This presents significant time and monetary savings for manufacturers. 
     According to embodiments, the transparent resin of the window  56  is a thermoplastic resin having high impact resistance and toughness, such as acrylonitrile butadiene styrene (ABS). Additionally, the window  56  formed by a resin is significantly lighter in weight than a typical glass window, thereby significantly reducing the weight of the vehicle component construct. According to embodiments, the ABS resin includes from 15 to 35% acrylonitrile, 5 to 30% butadiene, and 40 to 60% styrene. Components formed from ABS resin have high impact resistance and toughness, making ABS particularly well suited for forming a vehicle window. The transparent resin can be tuned to improve impact resistance, toughness, and heat resistance. For example, impact resistance can be amplified by increasing the proportions of polybutadiene in relation to styrene and also acrylonitrile, although this causes changes in other properties. Impact resistance does not fall off rapidly at lower temperatures. The transparent resin can be further tuned by modifying the conditions under which the material is processed to the final product. For example, molding at a high temperature improves the gloss and heat resistance of the product whereas the highest impact resistance and strength are obtained by molding at low temperature. Fibers (usually glass fibers) and additives can be mixed in the resin pellets to make the final product strong and raise the maximum operating temperature as high as 80° C. (176° F.). According to embodiments, particles are added to the transparent resin such that the window  56  is tinted to provide UV protection within the vehicle. According to embodiments, additives are provided in the transparent resin to increase the window&#39;s  56  ability to withstand the harmful effects of ultraviolet radiation. 
     According to embodiments, the window  56  is formed of glass. In such embodiments, a glass window  56  may be positioned in such a way that the frame  54  is molded around the glass window  56 . Alternatively, the glass window  56  is bonded to a lip that surrounds the through opening  62  formed in the frame  54 . 
     According to embodiments, the window  56 , formed of either glass or a transparent resin, includes window defroster elements that are molded into the window  56 . According to embodiments, the window defroster elements are a plurality of wires that are configured to be electrically heated such that any frost, fog, or ice that forms on the window  56  can be removed by the heating of the wires. According to embodiments, the window defroster elements of the window  56  include a connector that is positioned outside of the window  56 . The connector is configured to be connected with a corresponding connector positioned on the frame  54 . 
     As noted above, the frame  54  is formed of a composite sandwich panel material  10 . The composite sandwich panel material  10  includes an open area core  12  with walls  26  defining an ordered array of pores  24  terminating in faces  17  and  17 ′, a high gloss surface sheet  14  adhered to a first face  17  of the open area core  12  by a first adhesive layer  20 , and a structural skin  16  adhered to a second face  17 ′ of the open area core  12  by a second adhesive layer  22 . The high gloss surface sheet  14  has a high gloss finish suitable as an auto body exterior surface. According to embodiments, the exterior surface  58  of the frame  54  is defined by the high gloss surface sheet  14  of the composite sandwich panel material  10  and the oppositely opposed interior surface  60  of the frame  54  is defined by the structural skin  16  of the composite sandwich panel material  10 . Thus, the frame  54  is formed as a structural part and simultaneously as a decorative part with no additional high gloss panel separate from the frame  54  being needed to complete the vehicle component. 
     As shown in  FIG. 4 , a portion of the surface sheet  14  is cutaway to reveal the adhesive  20 , a cloth, if present; and the open area core  12 . The surface sheet  14  is adhered to a first side of the open area core  12  by a first adhesive layer  20 . According to embodiments, the surface sheet  14  presents an outwardly facing high gloss surface  15 .  FIG. 5  is an enlarged cross-sectional view of a composite sandwich panel material  10  used to form the inventive vehicle component construct  52  according to embodiments of the invention.  FIG. 5  shows further details of the various layers making up the composite sandwich panel material  10 . In some embodiments, a cloth  19  is present intermediate between the face  17  of the open area core  12  and the surface sheet  14 , the cloth  19  being embedded within the adhesive  20 . The structural skin  16  is adhered to an opposing second side of the open area core  12  by a second adhesive layer  22 . In some embodiments, a cloth  19 ′ is present intermediate between the face  17 ′ of open area core  12  and the structural skin  16 , the cloth  19 ′ being embedded within the adhesive  22 . 
     According to embodiments, the open area core  12  is formed of a lightweight material that defines a plurality of pores  24  so as to reduce the overall density of the open area core  12 . The open area core  12  is formed from a variety of materials that include cellulosics such as corrugated fiberboard, paper board, paper stock; thermoplastics such as poly(methyl methacrylate) (PMMA), acrylonitrile butadiene styrene (ABS), polyamides, polylactides, polybenzimidazoles, polycarbonates, polyether sulfones, polyethylene, polypropylene, polystyrene, polyvinyl chloride, and block copolymers of any one of the aforementioned where at least one of the aforementioned makes up the majority by weight of the copolymer and regardless of the tacticity of the polymer or copolymer; thermosets such as polyesters, polyureas, polyurethanes, polyurea/polyurethanes, epoxies, vinyl esters; metal such as aluminum, magnesium, and alloys of any one of the aforementioned where at least one of the aforementioned metals constitutes the majority by weight of the alloy; a foam formed from polyurethane, polyethylene, ethylene vinyl acetate, polypropylene, polystyrene, polyvinyl chloride, oraerogels, regardless of whether the foam is open-celled or closed-celled. The top edges of the walls  26  that define the pores  24  in certain embodiments of the open area core such as  12  form an array of various shapes, such as hexagonal, circular, rhomboidal, triangular, parallelogram quadrilateral, and regular quadrilateral, honeycombs, diamonds, squares, triangles, parallelograms, circles, or a combination thereof. In some embodiments, the ratio of the thickness of a wall  26  to the maximal linear extent between faces  17  and  17 ′ is between 0.01-10:1. A wall thickness ranges from 0.1 mm to 100 mm in such embodiments. 
     The adhesive layers  20 ,  22  are formed of either a thermoplastic or curable formulation, a polyurethane or polyurethane prepolymer adhesive, which may be in the form of glue, a moisture cure adhesive, a reactive hot melt adhesive, or a polyurethane resin. As shown in  FIG. 5 , due to the compressive force applied to the adhesive layers  20 ,  22  between the surface sheet  14  and the open area core  12  and the structural skin  16  and the open area core  12 , the adhesive  20 ,  22  is engineered to have an initial viscosity on contact with the face  17  and the walls  26  so as partially fill the pores  24  of the open area core  12 . The viscosity of the adhesive layers  20 ,  22  ensures that the adhesive does not excessively run into the pores defined in the open area core before the adhesive attains final strength. Accordingly, the adhesive surface area for adhesion between a surface sheet and structural skin and the open area core is at least 5% more than surface area of the walls at the face. This increased surface area of adhesion reduces delamination of the components of the composite sandwich  10  and surprisingly allows for the use of thinner surface sheets that do not exhibit bond line read through. As a result of increasing the adhesive surface area coverage from 10 to 50 surface area percent allows for the comparatively expensive high gloss surface sheet to be reduced in thickness from 1.5 mm to between 1.3 and 0.8 mm while still preventing of bond line read through. 
     The high gloss surface sheet  14  of the composite sandwich panel  10  is formed from sheet molding compound (SMC), thermoplastic, dicyclopentadiene (DCPD), overmolded polyurethane (PU), or a combination thereof. According to embodiments, the surface sheet  14  is a high gloss surface sheet having a high gloss surface  15 . The surface sheet  14  can include a filler material  30  to reinforce and/or serve to decrease the weight of the high gloss surface sheet  14 . The filler material  30  is any of glass fibers, carbon fibers, natural fibers, hollow or solid glass microspheres, or a combination thereof. The fibers may be oriented or non-oriented. In some inventive embodiments in which SMC forms the high gloss surface, a resin package sold by Continental Structural Plastics, Inc. under the tradenames TCA® and TCA® ULTRA-LITE™ are used herein. Exemplary formulations of which are detailed in U.S. Pat. No. 7,700,670; WO2017/184761; and U.S. Pat. No. 7,524,547B2. It is appreciated that the high gloss sheet routinely includes additives to retain dimensionality. Such additives routinely including glass fiber; carbon fiber; inorganic particulate fillers such as calcium carbonate, talc, and carbon black; glass microspheres; carbon nanotubes; graphene; low profile additives; moisture scavengers; and combinations thereof. Typical thicknesses of the high gloss surface sheet in the present invention range from 0.5 to 5 millimeters (mm) without regard to edges. 
     According to embodiments, a colorant is added to the sheet molding compound (SMC), thermoplastic, dicyclopentadiene (DCPD), overmolded polyurethane (PU), or a combination thereof that forms the high gloss surface sheet  14  of the composite sandwich panel  10 . Thus, the exterior surface  58  of a frame  54  formed of such a composite sandwich panel  10  is provided with the color of the vehicle exterior, thereby eliminating additional component finishing processes, such as priming and painting. 
     As will be understood by a person having ordinary skill in the art, the high gloss surface sheet tends to be a comparatively dense component and an expensive portion to manufacture given the materials used and necessary forming processes to maintain minimal perceptible surface defects suitable for a Class A autobody part. To reduce costs and weight of the composite sandwich panel material  10 , it is accordingly desirable to reduce the thickness of the high gloss surface sheet  14 , making it as thin as possible. It will also be understood that as the thickness of the high gloss surface sheet  14  is decreased the high gloss surface sheet  14  tends to deform when supported by limited portions of the face  17  above the open area core  12 . While result to a large contact surface area of the first adhesive layer  20  is advantageous, in some inventive embodiments a cloth  19  is embedded in the first adhesive layer  20 . 
     The structural skin  16  is adhered to the second side of the open area core  12  by the second adhesive layer  22 . The structural skin  16  is formed of a fiber mat having non-oriented, non-woven fibers, unidirectional, or woven fibers, a thermoplastic sheet, or an SMC. The structural skin  16  provides a robust and durable surface. In some embodiments, the structural skin  16  terminates against the backside of the surface sheet  14  to encapsulate the open area core  12 . 
     According to certain embodiments, the composite sandwich panel material  10  provides sound damping, fire retardancy, thermal insulation, or a combination thereof by placing a sound and/or heat absorbing material within the pores  24  of the open area core  12 . According to embodiments, the pores  24  of the open area core  12  are at least partially filled with a fill  49 . The fill illustratively including foam pellets, fire retardant, or a phase change material. Phase change materials operative herein include waxes or an inorganic salt hydrates. 
     The surface sheet  14  and the structural skin  16  are joined together along an edge  33 A- 33 D of the composite sandwich panel material  10  to form a seal, as shown in  FIGS. 6A-6D , respectively. In certain embodiments in which all of the edges of the composite sandwich panel assembly  10  are sealed, the open area core  12  is fully enclosed and moisture is inhibited from entering the interior of the composite sandwich panel assembly  10 . Given that the components of the inventive vehicle component construct  52  formed of the composite sandwich panel assembly  10  are exposed to natural elements including sun, snow, humidity, and rain, preventing moisture from entering the interior of the composite sandwich panel material  10  is important given that freeze thaw cycles of moisture within the part cause expansion and potentially failure of the composite sandwich panel material  10 , leading to damage to the vehicle component construct  52 . Additionally, in embodiments in which the open area core  12  is formed of a hydrophilic material such as paper, moisture within the composite sandwich panel assembly  10  would destroy the open are core  12  and cause the part to fail. 
       FIGS. 6A-6D  show various embodiments of ways in which the surface sheet  14  and the structural skin  16  are joined together to form a sealed edge  33 A- 33 D, respectively according to the present disclosure. In some inventive embodiments an elastomeric gasket  34  is disposed between the surface sheet  14  and the structural skin  16  at the  33 C to make the edge  33 C more water resistant. It is appreciated that a gasket is readily included in the other edge joinder  33 A,  33 B, and  33 D. The gasket  35  enhances maintenance of the edge seal over a wider range of use conditions. 
     As will be understood by one having ordinary skill in the art, to form an edge seal between the surface sheet  14  and the structural skin  16 , at least one of the surface sheet  14  and the structural skin  16  requires enough material to wrap around the edge of the composite sandwich  10 . According to embodiments, at least one of the surface sheet  14  and the structural skin  16  is provided in dimensions greater than the dimensions of the final composite part such that the material is able to wrap around the final edge composite sandwich  10 . According to certain embodiments, the at least one of the surface sheet  14  and the structural skin  16  is preformed such that it has edges extending generally perpendicularly from the plane of the sheet material. 
     According to embodiments, excess material is cut from the composite sandwich once the edge seal is formed. As shown in  FIG. 6A , excess material of the structural skin  16  has been trimmed from the composite sandwich assembly  10  by a knife or router that presses against the divot  35 A that is formed by the surface sheet  14 . In  FIG. 6B , the edge  33 B formed by removing excess material for tool engagement against a shoulder  35 B of the surface sheet  14 . In  FIG. 6C , the edge  33 C formed by removing excess material for tool engagement against a shoulder  35 C of the surface sheet  14 . Also, as shown in  FIG. 6D , excess material of one or both the surface sheet  14  and the structural skin  16  are trimmed with tool pressure against shoulder  35 D. 
     Given that the surface sheet  14  and the structural skin  16  of the composite sandwich panel material  10  are joined together to form sealed edges  33 A- 33 D, thereby protecting the open area core  12  within the surface sheet  14  and the structural skin  16 , the frame  54  of an inventive vehicle component construct  52 ,  52 ′,  52 ″,  52 ′″,  52 ″″ according to embodiments is submerged in paint for finishing. According to embodiments, the frame  54  is e-coated, that is the frame  54  is submerged in an electrically charged coating that is attracted to the frame  54  to evenly coat the frame. 
     Referring again to  FIGS. 1-3 , embodiments of an inventive vehicle component include a tailgate, liftgate, or hatch door  52 ; a sliding door  52 ′; a body panel  52 ″,  52 ″″; or a roof panel  52 ′″, for example having a moon roof. According to embodiments, a tailgate, liftgate, or hatch door  52  or a sliding door  52 ′ include a locking mechanism  64 . The locking mechanism  64  is positioned on the interior surface  60  of the frame  54  that is defined by the structural skin  16  of the composite sandwich panel material  10 . According to embodiments, the locking mechanism is attached to the frame  54  after the frame  54  is shaped and formed, which may include cutting an opening in the interior surface  60  of the frame that corresponds to the shape and desired location of the locking mechanism  64 . The locking mechanism  64  may include a latch and a catch that are configured to cooperate with one another in order to hold the tailgate, liftgate, or hatch door  52 , or sliding door  52 ′ in a closed position relative to the vehicle frame. 
     As shown in  FIG. 7 , embodiments of an inventive tailgate, liftgate, or hatch door  52 ; a sliding door  52 ′; a body panel  52 ″,  52 ″″; or a roof panel  52 ′″ include a conduit system  120  embedded within the composite sandwich panel material  10  of the frame  54  of each vehicle component. As shown in  FIG. 7 , the conduit system  120  is embedded in the open area core  12  of composite sandwich panel assembly  10  that forms the frame  54  of the inventive tailgate, liftgate, or hatch door  52 ; a sliding door  52 ′; a body panel  52 ″,  52 ″″; or a roof panel  52 ′″. According to embodiments, the conduit system  120  comprises tubing or wires that are molded into the open area core  12  of the composite sandwich  10  before the frame  54  of a vehicle component is formed. According to embodiments, the conduit system  120  includes electrical wiring, ventilation ducts, or heating elements. Accordingly, embodiments of the inventive tailgate, liftgate, or hatch door  52 ; a sliding door  52 ′; a body panel  52 ″,  52 ″″; or a roof panel  52 ′″ are capable of including features such as speakers, lights, air vents for regulating the climate within the vehicle, and defrosting elements for removing ice or snow present on the vehicle component or the window formed therein. The conduit systems  120  of various vehicle components are configured to align with one another to form a single connected conduit system throughout the vehicle to connect electrical wiring, ventilation ducts, and/or heating elements of each of an inventive tailgate, liftgate, or hatch door  52 ; a sliding door  52 ′; a body panel  52 ″,  52 ″″; or a roof panel  52 ′″ with like electrical wiring, ventilation ducts, and/or heating elements of the vehicle to function. 
     According to embodiments, a tailgate, liftgate, or hatch door  52  or a sliding door  52 ′ include a handle  66 . The handle  66  is positioned on the exterior surface  58  of the frame  54  that is defined by the high gloss surface sheet  14  of the composite sandwich panel material  10 . According to embodiments, the handle  66  is attached to the frame  54  after the frame  54  is shaped and formed, which may include drilling attachment holes in the exterior surface  58  of the frame that corresponds to the shape and desired location of the handle  66 . 
     According to embodiments, a tailgate, liftgate, or hatch door  52  include a plurality of hinges  68  that movably attach the tailgate, liftgate, or hatch door  52  to the vehicle frame. According to embodiments, the hinges  68  are attached to the interior surface  60  of the frame  58  of the composite construct. According to embodiments, the frame includes a plurality of cutouts  70  that correspond in shape and desired location to the hinges  68 . Such cutouts  70  are formed in the frame  54  by either cutting the cutouts  70  out from the material of the frame  54  or by forming the cutouts  70  in the frame by molding when the frame  54  is formed. According to embodiments, the cutouts  70  are positioned along an upper or top edge of the frame  54 , as shown in  FIG. 3 . In such a case, the tailgate, liftgate, or hatch door  52  pivots about the hinges  68  to move upward to an open position, as shown in  FIG. 2 . According to embodiments, the hinges are positioned along a side edge of the frame  54 , such that the tailgate, liftgate, or hatch door  52  pivots about the hinges  68  to move upward to an open position. 
     According to embodiments, a tailgate, liftgate, or hatch door  52  includes a wiper blade  72  pivotably mounted to the exterior surface  60  of the frame  54 . The wiper blade  72  is configured to engage with the window  56  to wipe liquid, debris, and dirt from the surface of the window  56 . According to embodiments, the wiper blade  72  is attached to the frame  54  after the frame  54  is formed. Accordingly, attaching the wiper blade  72  may include drilling an attachment hole into the exterior surface  58  of the frame  54  and attaching the wiper blade  72  thereto with a fastener. 
     As shown in  FIG. 2 , embodiments of a tailgate, liftgate, or hatch door  52  includes a safety cable  51  that is configured to be attached between the tailgate, liftgate, or hatch door  52  and the vehicle body. According to embodiments, the safety cable  51  is embedded in the tailgate, liftgate, or hatch door  52  at a first end of the safety cable  51  and is attachable at the opposite end of the safety cable  51  to the frame of the vehicle body. The safety cable  51  thus connects the tailgate, liftgate, or hatch door  52  to the vehicle body at a point in addition to the hinges  68 . Thus, in the event of a crash or failure of the hinges  68 , the tailgate, liftgate, or hatch door  52  is remains connected to the vehicle body. According to embodiments, a vehicle component construct, such a sliding door  52 ′, includes a roller system (not shown) positioned on the interior surface  60  of the frame  54 . The roller system is configured to glide in a track  74  positioned on or formed in an exterior surface  58  of a body panel  52 ″ of the vehicle  50 . 
     Patent documents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the invention pertains. These documents and publications are incorporated herein by reference to the same extent as if each individual document or publication was specifically and individually incorporated herein by reference. 
     The foregoing description is illustrative of particular embodiments of the invention but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.