Patent Application
20060091574
1. Field of the Invention
The invention relates to interior vehicle trim panel having a sprayed expanded polyurethane layer, and to a method and system of making such parts.
2. Background Art
One example of a relatively typical vehicle interior trim panel comprises a relatively rigid substrate having a relatively flexible thin plastic skin disposed over at least an interior facing portion of a surface of the substrate. For some panels where a softer touch is desired, foam has been provided between the substrate and the skin. For these types of panels, a foam in place process is often times used to provide the foam. In this type of process, the skin and the substrate are positioned spaced apart in a mold while foam is molded there between. After the foam is molded, the foam extends between and secures the skin to the substrate.
There are occasions where trim panels having a soft feel are desired but because of design constraints are not easily manufacturable. One example is of a door panel having a soft feel above the belt line to match the appearance and feel of the instrument panel. Another example is of a trim panel, such as a door panel or instrument panel, that has undercuts, sharp radii, or other design configuration that results in relatively small, or somewhat significantly uneven, clearances between the skin and the substrate. In these, and other, types of designs, foam in place may have drawbacks that could prevent such a technique from being a suitable option.
Under the invention, a method of making a vehicle interior trim panel is provided. In at least one embodiment, the method includes providing a skin layer on a spray tool, providing a source of polyol, and providing a source of isocyanate, wherein at least one of the sources contains a nucleated component. The method of this embodiment further comprises combining polyol and isocyanate from their sources to form expandable polyurethane reactive component, spraying the expandable polyurethane reactive component onto the skin layer to form a resilient layer, and securing a rigid substrate to the resilient layer to form the vehicle interior trim part.
In at least one embodiment of the invention, the resilient layer has a density of 0.1 to 0.75 g/cm3. In at least another embodiment of the invention, the nucleated component is nucleated polyol having a specific gravity of 0.7 to 0.95. In at least yet another embodiment of the invention, the resilient layer comprises 35-90% closed cell structures.
The present invention also provides a system for making vehicle interior trim panel for use with a motor vehicle. In at least one embodiment, the system comprises a spray tool for receiving a skin layer, a source of polyol, and a source of isocyanate, with at least one of the sources containing a nucleated component and each source is capable of delivering a stream of material combinable with the other stream to form expandable polyurethane reactive component. The system of this embodiment further comprising a spraying device for spraying the expandable polyurethane reactive component onto the skin layer to form a resilient layer, and a device for securing a rigid substrate to the resilient layer to form the vehicle interior trim part.
In at least one embodiment, the present invention also provides a vehicle interior panel for a vehicle interior made in accordance with at least one method and/or system of the present invention.
While exemplary embodiments in accordance with the invention are illustrated and disclosed, such disclosure should not be construed to limit the claims. It is anticipated that various modifications and alternative designs may be made without departing from the scope of the invention.
As required, detailed embodiments of the present invention are disclosed herein. However, it is to be understood that disclosed embodiments are merely exemplary of the invention that may be embodied in various alternative forms. The figures are not necessarily to scale, some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or a representative basis for teaching one skilled in the art to variously employ the present invention.
Moreover, except where otherwise expressly indicated, all numerical quantities in this description and in the claims indicating amounts of materials or conditions of reactions and/or use are to be understood as modified by the word “about” in describing the broadest scope of this invention. Practice within the numeral limit stated is generally preferred. Also, unless expressly stated to the contrary, percent, “parts of,” and ratio values are by weight and the description of a group or class of materials as suitable or preferred for a given purpose in connection with the invention implies that mixtures of any two or more members of the group or class may be equally suitable or preferred.
As shown in
The substrate 20 is a structural member that provides support for the remainder of the instrument panel 10, and may comprise any suitable material. For example, the substrate 20 may be made of plastic or reinforced plastic, such as fiberglass reinforced polyurethane (GRU). Additional examples of suitable plastics, besides polyurethane, include polypropylene, polyethylene, acrylonitrile butadiene styrene (ABS), polycarbonate (PC), and ABS/PC blends. In at least one embodiment, the substrate 20 may have an average thickness between 0.5 to 5 mm, in another embodiment 1.0 to 3.5 mm, and in yet another embodiment 2.0 to 3.0 mm.
In at least one embodiment, the resilient layer 22 is adhered to the substrate 20 and the skin layer 24 and may be configured to help provide a soft feel to the instrument panel 10. The resilient layer 22 may comprise any suitable sprayed expanded polyurethane material. For example, the resilient layer 22 may comprise an expanded aromatic polyurethane elastomer. In at least one embodiment, the density of the resilient layer 22 can be in the range of 0.10 to 0.75 grams per cubic centimeter (g/cm3), in another embodiment between 0.15 to 0.5 g/cm3, and in yet another embodiment 0.2 to 0.3 g/cm3. In at least one embodiment, the resilient layer may have a shore A hardness of 30 to 50.
In at least one embodiment, the resilient layer 22 primarily may comprise a low permeable, relatively closed cell material. In at least one embodiment, the resilient layer 22 may comprise 35 to 90 percent closed cell structures, in at least another embodiment 40 to 75 percent closed cell structures, and in yet at least another embodiment 45 to 60 percent closed cell structures, based upon the entire resilient layer 22.
In at least one embodiment, the resilient layer 22 may have varying closed cell density throughout the resilient layer. In at least one embodiment, the top portion (the portion closer to the skin layer 24) and the lower portion (the portion closer to the substrate 20) may independently comprise at least 85 percent closed cell structures, in other embodiments between 90 to 100 percent closed cell structures, and in yet other embodiments between 95 and 100 percent closed cell structures. In at least one embodiment, the top and bottom portions may independently comprise between 2.5 to 25 percent, in other embodiments between 5 to 20 percent, and in yet other embodiments between 10 to 15 percent, of the thickness t of the resilient layer 22. The remaining intermediate layer (the portion between the top and bottom portion) of the resilient layer 22 may comprise between 40 to 95 percent closed cell structures, in at least another embodiment between 50 to 90 percent closed cell structures, and in yet another embodiment between 60 to 85 percent closed cell structures. In at least one embodiment, the average cell structure size can vary between 0.05 mm to 3.0 mm, and in yet other embodiment between 0.5 mm to 1.0 mm.
The skin layer 24 is adhered to the resilient layer 22 and optional coating 26. Moreover, the skin layer 24 is configured to provide a covering over the resilient layer 22 and may comprise any sufficiently dense material. For example, the skin layer 24 may be a solid layer that comprises an aromatic or aliphatic compound. As a more specific example, the skin layer 24 may be made of an elastomer such as polyurethane. Furthermore, the skin layer 24 may have any suitable thickness and density. For example, the skin layer 24 may have a thickness in the range of 0.4 to 2 mm, and a density in the range of 0.85 to 1.2 g/cm3. In one embodiment of the invention, the skin layer 24 has a thickness in the range of 0.5 to 1.2 mm, and a density in the range of 0.95 to 1.1 g/cm3.
The optional coating 26 may be used to protect the skin layer 24 and/or to provide a decorative surface for the upper door portion 14. For example, the coating 26 may be used to inhibit sunlight and/or other ultraviolet light from reaching the skin layer 24. As another example, the coating 26 may be used as a paint to provide a desired color and/or texture to the upper door portion 14. While the coating 26 may comprise any suitable material, in at least one embodiment of the invention, the coating 26 is made of an aliphatic polyurethane composition. Furthermore, the coating 26 may have any suitable thickness, such as a thickness of approximately 0.5 to 1.0 mil.
Alternatively, the coating 26 may be omitted if not required for a particular application. For example, the skin layer 24 may be configured to provide a sufficiently durable and attractive surface such that the coating 26 is not needed.
Referring to
Next, referring to
As mentioned above, the coating 26 may be omitted from the upper door portion 14. In such a case, the skin layer forming material may be sprayed directly onto the tool 30, or onto a mold release agent that is applied on the tool 30, to form the skin layer 24. In this embodiment, the polyurethane skin layer 24 is preferably aliphatic.
Referring to
As is well known in the art, the primary components of polyurethane are polyol and isocyanate. As such, it should be understood that the nucleated component could be nucleated polyol, nucleated isocyanate, or both. A “nucleated material” should be understood to mean a “frothed material” or a material having a lower density compared to the unnucleated material caused at least in part by the mechanical mixing of liquid and/or gaseous low boiling point gas/bubble generating agent (such as carbon dioxide), into the material. In at least one preferred embodiment, the nucleated component material is nucleated polyol. As such, in the remainder of this description, the nucleated component will be referred to in a non-limiting manner as nucleated polyol, however it should be understood that the nucleated component may be something other than that, such as nucleated isocyanate, as described above. In at least one embodiment, the expandable polyurethane material comprises nucleated polyol from nucleated polyol source 40, isocyanate from isocyanate source 42, and any other necessary components for forming polyurethane.
In at least one embodiment, nucleated polyol is polyol that has experienced a 5 to 25% reduction in specific gravity. In certain embodiments, the nucleated polyol has a specific gravity of 0.70 to 0.95, and in other embodiments of 0.75 to 0.85.
As shown in
In at least one embodiment, the expandable polyurethane material may be sprayed with the same type of robotic spray assembly 36 as used in
It should be understood that the expandable polyurethane material may be sprayed to achieve any desired thickness t at any location, such that the thickness of the resilient layer 22 may be varied. Thus, the expandable polyurethane material may be more lightly applied in certain areas such as where there is less clearance between substrate 20 and skin 24, and more heavily applied in areas, where there is more clearance between substrate 20 and skin 24. Furthermore, an optional embodiment, a layer (not shown) of conventional foam-in-place foam could be conventionally disposed between resilient layer 22 and substrate 20.
Referring to
In at least one embodiment, the expandable polyurethane material may be sprayed with the same type of robotic spray assembly 36 as used in
In yet another embodiment, nucleation fluid, polyol and isocyanate could be mixed together (not shown) in a spray assembly to form an expandable polyurethane material that can be sprayed onto the skin layer 24 to form resilient layer 22.
Next, the method involves securing the substrate 20 to the expanded polyurethane layer 22. In one embodiment, this can be done by removing the coating 26, skin layer 24 and resilient expanded polyurethane layer 22 from the tool 30 and positioning the layers 22, 24 and 26 in a mold having first and second mold portions. The mold portions may then be closed together, with material being injected into the mold through one or more injection passages (not shown) to form substrate 20, which bonds to the resilient layer 22. Alternatively, the material may be poured into the mold, and then the mold portions may be closed together.
While the substrate material may comprise any suitable substance or substances, in one embodiment, the material includes polyol and isocyanate such that the substrate 20 is formed of polyurethane. Other suitable materials include polypropylene, polyethylene, ABS, PC, ABS/PC blends, GRU and RRIM.
Whether the material is injected or poured into the mold, such a process may be referred to as reaction injection molding (RIM). Reinforcing material such as milled glass or glass fibers may also be added during the RIM process to provide reinforcement to the substrate 20. As another example, a reinforcing mat or preform, such as a fiberglass preform, may be positioned in the mold prior to the RIM process. This process may be referred to as structural reaction injection molding (SRIM). RRIM is the process where milled glass is mixed with polyol before reacting the polyol with the isocyanate.
In at least one embodiment, the substrate 20 could be a preformed substrate that is secured to the layer 22 by suitable means, such as adhesively.
Examples of other vehicle parts that may be manufactured by the above method include instrument panels, door panels, door covers, package shelves, pillar trim panels, trim covers, and console covers.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
