Vehicular window assembly

Details Vehicular window assembly Vehicular window assembly

2000-07-17

2001-09-25

Pape, Joseph D. (Department: 3612)

Land vehicles: bodies and tops

Bodies

Door or window with specified vehicle feature

C296S093000, C052S204591

Reexamination Certificate

active

06293609

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to panel assemblies, and more particularly, to window panel assemblies having a gasket mounted on one or more sides of a sheet of glass or plastic and used as a panel or window in a vehicle, building or other structure, as well as a method for making such window assemblies. Such window assemblies are commonly known in the vehicle industry as “modular windows.”
Modern modular vehicle windows include a gasket attached by molding or extrusion directly onto the glass panel. In manufacturing molded, modular window panels, a sheet of glass is closed within a molding tool, and a polymeric material is injected around the peripheral edge on opposing surfaces or on a single surface of the sheet edge, thereby attaching the polymeric material to the peripheral edge of the glass panel. After the material is cured, the mold is opened and the panel assembly is removed. To retain the modular window assembly within the vehicle, studs or clips may be molded within or attached to the gasket and panel and used to engage the pinch weld flange forming the vehicle opening. Alternately, or in addition thereto, a bead of adhesive can be applied to bond the panel assembly directly to the pinch weld flange.
One category of modular windows includes assemblies having an exposed peripheral edge on the glass panel known as “flush-mounted” window assemblies. One such flush-mounted vehicle includes an extruded gasket of thermosetting material deposited directly on the surface of a glass sheet. In other assemblies, the extrusion includes two adhesive beads of polyurethane compounds, one deposited by the panel assembly manufacturer and the other applied by the vehicle assembler. Such assemblies require a long cure time for the first bead, adding cycle time to manufacturing. In addition, the gasket material used in the forming the extruded gasket is typically not ultraviolet radiation stabilized by itself and can degrade over time upon exposure to the elements. Moreover, the extrusion process does not easily adapt itself to receiving mounting studs or clips, or to forming in variable cross sections. Extrusion is also expensive, and requires special storage and handling after manufacture.
Other window assemblies intended for use in flush-mounted applications include a gasket of thermosetting material molded directly to a single surface of panel in a molding machine using reaction injection molded (RIM) urethane. Although variable cross sections can be formed using this method, RIM urethane gaskets still degrade when subjected to prolonged exposure to UV light, require a long cycle time during manufacture, and have increased material costs compared with other materials. In addition, it is often found that the tension or shear force applied to the glass and RIM molded gasket results in failure of the adhesive seal between the gasket and the glass panel.
Additionally, gaskets formed with materials including urethane, RIM urethane, PVC and the like, often require the use of additional seals or sealants between the modular window assembly and the pinch weld flange of the vehicle in order to effectively exclude water, dirt, dust and the like from entering the vehicle. However, the use of such additional seals adds complexity, labor and expense to the vehicle assembly process.
Accordingly, a need exists in the vehicle industry for a modular vehicle window assembly which incorporates a gasket material suitable for formation of gaskets on one, two or three sides of the sheet window panel, for incorporation of fasteners which allow attachment of the assembly mechanically to the vehicle, and for elimination of the need for additional seals. In addition, the gasket material desirably should allow for a reduction in costs, and provide a reliable, high-strength bond between the window panel surface and gasket for long-term security in attachment of windows to the vehicles and wherein the gasket materials exhibit low to moderate compression set, good flexibility and resiliency, good low temperature operating characteristics, and good creep resistance.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a vehicular window assembly having a gasket bonded to one or more surfaces of a window panel wherein the gasket is formed from a polymeric material which can be attached to the window panel with a high strength bond, allows the incorporation of fasteners for mechanical securement of the window assembly to the vehicle without failure due to material creep, and has a consistency and resiliency sufficient to avoid the need for additional seals apart from the gasket itself. Preferably, the gasket is molded from a thermoplastic elastomer such a thermoplastic olefin. More preferably, the gasket is molded from an olefinic-styrenic copolymer. Most preferably, the gasket is molded from an ethylene-styrene copolymer, one example of which is ethylene-styrene interpolymer (ESI) formed from a melt-processible, low halogen or halogen free polymer resin material, such as a resin based on polyolefin and produced using a metallocene catalysis and having a durometer within the range of between about 30 and 110 on the Shore A scale, more preferably 65 to 95 Shore A, and most preferably 65 to 85 Shore A.
In one form, the vehicle window assembly of this invention includes a sheet-like panel having a pair of surfaces terminating in a peripheral edge. A primer layer is applied to a predetermined area of one panel surface. Applied to the panel on at a least a portion of the panel surface including the primer layer is a polymeric gasket. The gasket is formed from an olefinic-styrenic copolymer and is bonded to the primed panel portion.
In another form of the vehicle window assembly, the gasket may be molded to have a variable cross section around the same panel. Furthermore, the gasket may be molded about and partially encapsulate guiding or mounting hardware used to locate and/or fix the panel assembly in the vehicle window opening. In addition, the sheet glass or other window panel may include a layer of opaque, ceramic frit material on which the gasket is molded which conceals and hides the attachment area of the gasket when the window assembly is viewed from the exterior, such as when it is assembled in a vehicle.
Preferably, the primer layer has a transition temperature at or above which improved adhesion and bonding occurs. With this type of primer, the olefinic-styrenic copolymer such as the ethylene-styrene copolymer is molded on the glass panel while the panel and primer are at or above the transition temperature, which preferably is approximately 93° C. (200° F.) or greater.
Alternately, other primer materials can be used and achieve improved high temperature resistance. Such primers are cross-linkable primers consisting of functionalized polyolefins, thermoplastic elastomers (TPE's) including ethylene-styrene copolymer (inter-polymer), or urethanes, acrylics and epoxies which can be heat cured, ambient cured by cross linkers, or ambient moisture. Such a primer can be further activated by post heating the injection molded assembly with an external energy source, such as a controlled focus infrared (CFIR) source, a controlled area infrared (CAIR) source, or other heat sources.
According to yet another aspect of the invention, a vehicle window assembly is made according to the method of providing a panel having a primer coating having a known primer transition temperature applied to at least a portion of the panel surface. Subsequently, the panel and primer coating are heated to raise the temperature of the primer to at least the transition temperature of the primer. While maintaining the temperature of the panel and primer greater than the primer transition temperature, an olefinic-styrenic copolymer such as an ethylene-styrene copolymer gasket is molded onto the primer coating. The melt temperature of the polymeric material is preferably at a temperature at least equal to the transition temperature of the primer.
Alternately, a panel is coated with a cross-linkable primer

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